Influência de três modos de fotopolimerização sobre a microdureza de três resinas compostas

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Andréa Cristina Schneider

2016-01-01

Full Text Available Resumo A adequada fotopolimerização das resinas compostas é fundamental para obtenção de uma boa dureza capaz de resistir aos esforços mastigatórios. Assim, o objetivo deste estudo foi avaliar a influência das técnicas de fotopolimerização - Convencional (CONV, Soft-start (SS e Pulso atrasado (PA na microdureza Knoop de três resinas compostas. Para a confecção dos corpos-de-prova foram utilizadas as resinas compostas Filtek Z350 (3M ESPE, Empress Direct (IvoclarVivadent e P90 (3M ESPE. Foram obtidos nove grupos experimentais em função da técnica de polimerização e resina composta. Vinte e quatro horas após a fotopolimerização foi realizado o teste de microdureza Knoop nas superfícies de base e topo de cada corpo-de-prova. Assim, os valores obtidos foram submetidos ao teste de Kruskall Wallis, seguido do teste de Dunn, p < 0,05. A eficácia da polimerização na superfície de topo das resinas compostas testadas não foi afetada pelos diferentes modos de polimerização. A resina composta Empress Direct apresentou os mais baixos valores de dureza para todos os modos de polimerização quando comparada às demais resinas compostas avaliadas.

Documento de Idoneidad Técnica, Granulite CD.U.: 693621 S.F.B. Un 6 - Convalidación n.° 5 Agrément del C.S.T.B. n."2.117 Fecha: 28 de julio de 1965 - revestimiento interior de muros

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Nadal, J.

1965-10-01

Full Text Available Not availableEl revestimiento interior de muros GRANULITE se obtiene por aplicación, sobre la superficie a revestir, de una capa de pasta compuesta de un árido mineral y de im conglomerante constituido por una emulsión acuosa de resina sintética.

Resistência à flexão de resinas de metacrilato de metila e bisacrilato de metila submetidas à termociclagem

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Ataís Bacchi

Full Text Available OBJETIVO: Verificar a resistência à flexão de quatro resinas utilizadas para a confecção de restaurações temporárias submetidas à termociclagem. MÉTODO: Foram utilizadas as resinas da marcas Luxatemp e Structur 2, à base de bisacrilato de metila, e as resinas das marcas Duralay e Alike, à base de metacrilato de metila. Vinte espécimes de cada material foram confeccionados e divididos em dois grupos, para serem submetidos às seguintes condições: (I - 24 horas de armazenagem em saliva artificial, e (II - 24 horas de armazenagem em saliva artificial seguida de termociclagem (2000 ciclos, 5 °C-55°C. Cada amostra foi levada ao teste de resistência à flexão em uma Máquina de Ensaios Universal (EMIC DL 10000 e os dados obtidos foram analisados pelo teste ANOVA (dois fatores e, em seguida, pelo teste Tukey (p < 0,05. RESULTADO: As resinas de bisacrilato apresentaram resultados superiores de resistência à flexão após ambos os tempos de armazenagem, não diferindo estatisticamente entre si após 24 horas (p = 0,3594. A resina Luxatemp apresentou os maiores valores de resistência à flexão após a termociclagem, sendo estatisticamente superior às demais. A termociclagem alterou as propriedades mecânicas de todas as resinas, diminuindo a sua resistência à flexão (p = 0,001. CONCLUSÃO: As resinas de bisacrilato apresentam maior resistência à flexão do que as resinas de metacrilato para os fatores estudados. Todos os materiais utilizados neste estudo tiveram sua resistência reduzida pela ciclagem térmica.

Resinas quelantes amidoxímicas Amidoxime chelating resins

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Fernanda M. B. Coutinho

1999-12-01

Full Text Available Resinas quelantes com grupos amidoxima foram sintetizadas por copolimerização em suspensão de acrilonitrila (AN e divinilbenzeno (DVB e subsequente modificação química dos grupos ciano por reação com hidroxilamina. Na copolimerização, a proporção de divinilbenzeno e o grau de diluição foram variados. Gelatina e carbonato de cálcio foram usados como estabilizadores de suspensão e sulfato de sódio foi adicionado para reduzir a solubilidade da acrilonitrila em água, por meio do efeito salting out. Os copolímeros de AN/DVB e as resinas amidoxímicas obtidos foram caracterizados por meio de densidade aparente, área específica, volume de poros e teor de nitrogênio. As resinas amidoxímicas foram também avaliadas em relação a capacidade de complexação de íons cobre.Chelating resins with amidoxime groups were synthesized by suspension copolymerization of acrylonitrile (AN and divinylbenzene (DVB and subsequent chemical modification of cyano groups by reaction with hydroxylamine. In the copolymerization, the proportion of divinylbenzene and the dilution degree were varied. Gelatin and calcium carbonate were used as suspension stabilizers and sodium sulphate was added in order to reduce acrylonitrile solubility in water, by salting out effect. The AN/DVB copolymers and amidoxime resins obtained were characterized by apparent density, surface area, pore volume and by the content of nitrogen. The amidoxime resins were also evaluated in relation to the complexation capacity of copper ion.

Sensibilización a bisfenol A y bisfenol F en trabajadores expuestos a resinas epoxi

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L. Jiménez Bajo

2008-06-01

Full Text Available Las aplicaciones de las diferentes resinas epoxi basadas en bisfenol A y F son extensas. Las resinas epoxi basadas en bisfenol F son más nuevas y resistentes que las de bisfenol A, y ambas son causa conocida de dermatitis de contacto alérgica. Se estudian 39 casos de sensibilización a resinas epoxi en los últimos 5 años. Los resultados obtenidos son: prevalencia de sensibilización a resinas epoxi entre los pacientes estudiados del 2%, 27 varones y 8 mujeres, con una edad media de 42.77, un período de medio sensibilización de 23,8 meses. La sensibilización a bisfenol F desde que se incluye para las pruebas del parche en la batería de resinas epoxi es del 100% para los casos sensibilizados a la resina. La localización mayoritaria se dio en las manos, con una relevancia actual del 84%. Se recomendó un cambio de puesto en el trabajo al 46% de estos pacientes. El aumento de la sensibilización encontrada a bisfenol F puede explicarse por una sensibilización concomitante con bisfenol A, una declaración incorrecta de la composición de la resina o una reactividad cruzada de ambos.The applications of epoxy resins based on bisphenol A and F are extensive. Epoxy resins based on bisphenol F are new and more resistant than epoxy resins based on bisphenol A. Both of them cause allergic contact dermatitis. In the last 5 years, we have studied 39 cases of sensitization to epoxy resin. The results of our study were these: the global prevalence of epoxy resin sensitization was 2%, 27 men and 8 women. The mean age was 42.77 years and the sensitization period was 23.8 months. The most frequent localization of the lesions were hands (84% of the patients. Since bisphenol F was included in epoxy resin battery for patch testing, a 100% of positives responses in patients sensitized to epoxy resin have been found. Sensitization to epoxy resins was a cause of change in workplace in 46% of cases in our series. There has been an increase in sensitization of

Evaluación del efecto citotóxico de una resina dental a base de siloranos sobre fibroblastos L929

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Milena Guerrero F

2016-04-01

Full Text Available Introducción: Las resinas dentales basadas en siloranos, son el resultado de la unión química de siloxanos y oxiranos. Dentro del proceso de evolución de las resinas, se han modificado sus formulaciones para optimizar sus propiedades físicas, mecánicas y estéticas. Sin embargo, aún presentan problemas como la contracción de polimerización, problemas alérgicos y toxicológicos. Objetivo: Determinar el potencial efecto citotóxico de las resinas a base de siloranos sobre la viabilidad celular en un cultivo de fibroblastos de la línea L929. Metodología: Se estudió la exposición de fibroblastos de ratón L929 a resinas dentales a base de siloranos Filtek p90 y metacrilatos Filtek p60 en tres tiempos de fotocurado durante 6 días. Se evaluó el efecto sobre la viabilidad celular mediante pruebas de exclusión vital, micrografías electrónicas y composición elemental de superficie (Mg, Na, K y Ca por ESEM/EDAX. Resultados: La resina Filtek p90 mostró un mayor efecto citotóxico a tiempos de fotocurado prolongados (20 segundos o más respecto a la resina Filtek p60. El efecto resultó más marcado para 20 segundos de fotocurado, ya que las concentraciones de Ca y K en la superficie celular fueron las más afectadas. Conclusiones: La resina dental Filtek p90 ejerce un efecto citotóxico relativamente bajo sobre las células de fibroblastos L929 (p <0.01. Su uso en la práctica odontológica se puede considerar bioseguro, pero un tiempo de fotocurado prolongado con la resina dental a base de siloranos puede afectar significativamente la viabilidad de los tejidos dentales

Avaliação in vitro da microinfiltração em cavidades classe II de molares decíduos, restaurados com resina composta auto e fotopolimerizável

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CAVALCANTI Alessandro Leite; CHELOTTI Adolpho

1999-01-01

Estudou-se a microinfiltração marginal presente na interface da parede gengival de cavidades classe II em molares decíduos, restaurados com resina composta (auto e fotopolimerizável), através da penetração de uma solução corante. Os preparos cavitários apresentavam a parede gengival em esmalte e foram restaurados segundo 4 diferentes técnicas: 1) resina composta fotopolimerizável; 2) resina composta autopolimerizável; 3) resina composta auto e fotopolimerizável; e 4) ionômero de vidro/resina ...

FUNCIONALIZACIÓN DE UNA RESINA DE INTERCAMBIO IONICO PARA LA PRECONCENTRACION DE Hg(II

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Cecilia De Asmundis

2011-01-01

Full Text Available Se estudiaron las condiciones óptimas para funcionalizar una resina aniónica (Dowex 1X8 con un reactivo (difenilcarbazida específicamente adecuado para la determinación de Hg(II en soluciones acuosas. Se llevo a cabo el ajuste de las condiciones para la determinac ión del complejo Hg-DFC, las que permiten lograr un método eficaz, rápido y de bajo costo para detectar concentraciones de Hg en matrices complejas, mediante la realización de espectrofotometría de absorción UV-Vis en fase sólida. La resina puede ser utilizada para pre- concentrar Hg(II durante el pretratamiento para el análisis con métodos instrumentales específicos (absorción/emisión atómica. La intensidad del color desarrollado por la resina funcionalizada se encuentra estrechamente ligada con las concentraciones de Hg(II presentes en las muestras, lo que conduce a que el método pueda realizarse aún si no se tiene el equipamiento necesario, aplicando técnicas semi-cuantitativas como, colorimetria visual (naked eye.

The anticancer effects of Resina Draconis extract on cholangiocarcinoma.

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Wen, Feng; Zhao, Xiangxuan; Zhao, Yun; Lu, Zaiming; Guo, Qiyong

2016-11-01

Cholangiocarcinoma (CCA) is a relatively rare, heterogeneous malignant tumor with poor clinical outcomes. Because of high insensitivity to chemotherapy and radiotherapy, there are no effective treatment options. Efforts to identify and develop new agents for prevention and treatment of this deadly disease are urgent. Here, we assessed the apoptotic cytotoxicity of Resina Draconis extract (RDE) using in vitro and in vivo assays and identified the mechanisms underlying antitumor effects of RDE. RDE was obtained via vacuum distillation of Resina Draconis with 75 % ethanol. The ethanol extract could inhibit CCA cell proliferation and trigger apoptotic cell death in both QBC939 and HCCC9810 cell lines in a time- and concentration-dependent manner. RDE treatment resulted in intracellular caspase-8 and poly (ADP-ribose) polymerase protease activation. RDE significantly downregulated antiapoptotic protein survivin expression and upregulated proapoptotic protein Bak expression. RDE also inhibited CCA tumor growth in vivo. We observed that human CCA tissues had much higher survivin expression than did paired adjacent normal tissue. Taken together, the current data suggested that RDE has anticancer effects on CCA, and that RDE could function as a novel anticancer agent to benefit patients with CCA.

PROPRIEDADES FÍSICAS E MECÂNICAS DE PAINÉIS MDF DE DIFERENTES MASSAS ESPECÍFICAS E TEORES DE RESINA

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Jackson Roberto Eleotério

2000-08-01

Full Text Available Painéis MDF foram preparados, em escala laboratorial, com base em fibras de Pinus spp. com diferentes teores de resina (6, 8, 10, 12 e 14% e massas específicas (600 a 800 kg/m3 com o objetivo de avaliar suas propriedades físicas e mecânicas. Os efeitos da massa específica e do teor de resina, bem como sua interação foram avaliados tendo como base as propriedades físicas e mecânicas dos painéis MDF. As propriedades mecânicas avaliadas foram módulo de elasticidade e de ruptura e adesão interna, enquanto as propriedades físicas foram absorção de água e inchamento em espessura. Todas as variáveis se relacionaram significativamente com os fatores massa específica e teor de resina e a interação foi significativa a 1% apenas no inchamento em espessura. Foram propostos modelos para avaliar as propriedades físicas e mecânicas em razão da massa específica e do teor de resina.

Análise de peças anatômicas preservadas com resina de poliester para estudo em anatomia humana

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Ítalo Martins de Oliveira

Full Text Available OBJETIVO: avaliar o uso da resina de poliéster na preservação de peças anatômicas para estudo da anatomia humana. MÉTODOS: foram utilizadas 150 peças anatômicas, sendo as mesmas não fixadas (frescas, fixadas em formol a 10% e moldes vasculares de órgãos injetados com acetato de vinil e a resina de poliéster. A solução utilizada foi composta de resina de poliéster com seu diluente monômero de estireno e catalisador (peroxol. Foram obtidos, após a inclusão nesta solução, modelos em resina transparente, que permitiam a plena observação das estruturas e conservação da peça utilizada. RESULTADOS: na avaliação das peças, foi observado grau de extrema transparência, promovendo uma completa visualização das estruturas com a perfeita preservação da anatomia. A duração média para a completa finalização da inclusão foi 48 horas. Apenas 14 peças (9,3% foram inutilizadas durante o preparo. CONCLUSÃO: a resina de poliéster pode ser utilizada para a preservação de peças anatômicas para o ensino da anatomia humana, de maneira prática, estética e duradoura.

Bond strength of hard chairside reline resins to a rapid polymerizing denture base resin before and after thermal cycling Resistência de união de resinas rígidas para reembasamento imediato a resina para base de prótese de rápida polimerização antes e após termociclagem

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Karin Hermana Neppelenbroek

2006-12-01

Full Text Available PURPOSE: This study assessed the shear bond strength of 4 hard chairside reline resins (Kooliner, Tokuso Rebase Fast, Duraliner II, Ufi Gel Hard to a rapid polymerizing denture base resin (QC-20 processed using 2 polymerization cycles (A or B, before and after thermal cycling. MATERIALS AND METHODS: Cylinders (3.5 mm x 5.0 mm of the reline resins were bonded to cylinders of QC-20 polymerized using cycle A (boiling water-20 minutes or B (boiling water; remove heat-20 minutes; boiling water-20 minutes. For each reline resin/polymerization cycle combination, 10 specimens (groups CAt e CBt were thermally cycled (5 and 55 ºC; dwell time 30 seconds; 2,000 cycles; the other 10 were tested without thermal cycling (groups CAwt ad CBwt. Shear bond tests (0.5 mm/min were performed on the specimens and the failure mode was assessed. Data were analyzed by 3-way ANOVA and Newman-Keuls post-hoc test (alpha=.05. RESULTS: QC-20 resin demonstrated the lowest bond strengths among the reline materials (POBJETIVO: Esse estudo avaliou a resistência de união ao cisalhamento de 4 resinas rígidas para reembasamento imediato (Kooliner, Tokuso Rebase Fast, Duraliner II, Ufi Gel Hard a uma resina para base de prótese de rápida polimerização (QC-20 submetida a 2 ciclos de polimerização (A e B, antes e após termociclagem. MATERIAIS E MÉTODOS: Cilindros (3,5 mm x 5,0 mm das resinas reembasadoras foram unidas aos cilindros de resina QC-20 polimerizados pelo ciclo A (água fervente - 20 minutos ou B (água fervente; remoção do calor-20 minutos; água fervente-20 minutos. Para cada combinação resina reembasadora/ciclo de polimerização, 10 corpos-de-prova (grupos CAt e CBt foram termociclados (5 e 55 ºC; intervalo de tempo 30 segundos; 2.000 ciclos; os outros 10 foram testados sem termociclagem (grupos CAwt e CBwt. Os testes de resistência de união ao cisalhamento (0,5 mm/min foram realizados sobre os corpos-de-prova e o tipo de falha avaliado. Os dados foram

ANÁLISE AO MICROSCÓPIO ELETRÔNICO DE VARREDURA DAS PROJEÇÕES DE RESINA ("TAGS" EM DENTES RESTAURADOS APÓS INTERVENÇÃO ENDODÔNTICA

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SHIMABUKO Danilo Minor

1998-01-01

Full Text Available Avaliou-se in vitro, em 25 caninos humanos restaurados em nível coronário com resina composta fotopolimerizável após sofrerem intervenção endodôntica, a formação de projeções de resina ("tags" quanto a sua uniformidade e quantidade, variando-se o modo de aplicação, e a influência do ataque ácido e do uso de adesivos dentinários nas superfícies restauradas. Através da avaliação qualitativa por 3 observadores de fotomicrografias obtidas ao microscópio eletrônico de varredura, observou-se que houve formação de "tags" com melhor uniformidade no grupo em que se aplicou a resina fluida com bolinhas de algodão e imediata colocação da resina composta, sendo os dois materiais polimerizados conjuntamente, e com maior quantidade no grupo em que a resina fluida foi homogeneizada com jateamento de ar. A ausência de ataque ácido ou a não aplicação do sistema de adesão à dentina podem prejudicar a formação dos "tags" de resina.

Microdureza de caries incipientes artificiales infiltradas con resinas de baja viscosidad antes y después del termociclado

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X. Zamorano Pino; V. Valenzuela Aránguiz; C. Vial Prado; M. Vidal Tardón

2015-01-01

Introducción: En Odontología Mínimamente Invasiva, el procedimiento denominado Infiltración de caries, pretende detener la progresión de las caries incipientes mediante el sellado de las microporosidades del esmalte afectado. Este tratamiento se realiza con la aplicación de resinas de baja viscosidad. El objetivo de este trabajo fue evaluar la microdureza superficial de caries incipientes artificiales infiltradas con resinas de baja viscosidad antes y después del proceso de termociclado. Meto...

Avaliação in vitro da microinfiltração em cavidades classe II de molares decíduos, restaurados com resina composta auto e fotopolimerizável

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CAVALCANTI Alessandro Leite

1999-01-01

Full Text Available Estudou-se a microinfiltração marginal presente na interface da parede gengival de cavidades classe II em molares decíduos, restaurados com resina composta (auto e fotopolimerizável, através da penetração de uma solução corante. Os preparos cavitários apresentavam a parede gengival em esmalte e foram restaurados segundo 4 diferentes técnicas: 1 resina composta fotopolimerizável; 2 resina composta autopolimerizável; 3 resina composta auto e fotopolimerizável; e 4 ionômero de vidro/resina composta. Após a análise estatística dos resultados, concluiu-se que todos os grupos apresentaram microinfiltração em graus variados; todavia, os grupos 2, 3 e 4 apresentaram os menores graus de infiltração.

Análise da Fragilidade do Core - Quando reconstruído com diferentes resinas e pinos pré-fabricados não metálicos

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Ávilal, Gisseli Bertozzi; Dias, Sérgio Cândido; Ribeiro, José Carlos Rabelo; Gomes, Priscila Nogueira; Moysés, Marcos Ribeiro

2016-01-01

Para realização deste estudo vinte condutos artificiais foram construídos em blocos formados por esmalte e dentina, a partir de dentes bovinos. Dez pinos de fibra de vidro e dez de fibra de carbono foram cimentados nos condutos com cimento resinoso C&B. Empregou-se matriz de policarbonato para confecção do core em resina composta, perfazendo quatro grupos: Grupo (1) pino de fibra de vidro e core com resina composta Charisma; Grupo (2) pino de fibra de carbono e core com resina composta Charis...

Efecto del oxígeno y la glucosa en la metanogénesis y mineralización de resinas poliméricas

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Ulises Durán Hinojosa

2010-01-01

Full Text Available En el presente trabajo se evaluó el efecto de la concentración de oxígeno disuelto (OD y la presencia de la glucosa en la metanogénesis y mineralización de los compuestos de resinas poliméricas, mediante cultivos en lote. El inóculo utilizado para los cultivos fueron lodos procedentes de un reactor de lecho de lodos con flujo ascendente UASB (por sus siglas en inglés, alimentado con glucosa y aguas residuales de resinas poliméricas, y 1,0 mg L-1 d-1 de oxígeno disuelto en estado estacionario. Todas las pruebas fueron realizadas con 1500 mg L-1 de demanda química de oxígeno, a 30±2° C, con 23,8 g L-1 de sólidos suspendidos volátiles como inóculo y una relación demanda química de oxígeno / sólidos suspendidos volátiles de 1. El efecto de diferentes concentraciones de oxígeno disuelto mostró que, para la glucosa, con bajas concentraciones (0,6 y 1,0 mg L-1 la eficiencia de remoción de la demanda química de oxígeno y la actividad metanogénicas permanecieron constantes, pero la eficiencia de remoción de la demanda química de oxígeno para los compuestos de resinas poliméricas aumentó 58,1±1% y el rendimiento de metano disminuyó, debido a que una mayor fracción del carbono alimentado fue mineralizada a dióxido de carbono, posiblemente por una ruta aerobia. Los resultados con diferentes proporciones de glucosa / compuestos de resinas poliméricas (CRP en presencia de 0,6 mg L-1 de oxígeno disuelto mostraron que la presencia de glucosa no mejoró la eliminación de los compuestos de resinas poliméricas. Sin embargo, la actividad metanogénica disminuyó en un 75% cuando solamente se usó a los compuestos de resinas poliméricas como sustrato, al compararla con la actividad metanogénica con glucosa como única fuente de carbono, sugiriendo que la glucosa no favorece la eliminación de los compuestos de resinas poliméricas, pero proporciona una mejor tolerancia al oxígeno. Se concluye que la presencia de bajas

Análise por imagem digital dos níveis de cinza de fibras de reforço associadas a uma resina composta = Digital image analysis of the gray levels of reinforcement fibers associated with composite resin

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Mussatto, Cristiane Maria Boniatti

2005-01-01

Full Text Available Mensurar a densidade óptica das fibras de reforço Connect, Ribbond e Interlig incluídas em resina composta Filtek Z250, no sistema DenOptix. Materiais e método: Foram confeccionados 10 blocos de resina composta associadas a cada tipo de fibra e dois blocos de resina Z250 pura (controle não-reforçado, totalizando 32 corpos-de-prova. Foram obtidas 3 radiografias digitais de cada corpo-de-prova, sobre uma placa óptica do sistema DenOptix, para cada posição: (A face lateral da fibra exposta aos raios -X; (B face tramada da fibra exposta aos raios-X. Em cada uma foram realizadas 3 leituras ópticas dos níveis de cinza em cada corpo-de-prova, em pontos aleatórios, sendo obtida uma média. Os valores médios dos níveis de cinza foram analisados pelo teste t de Student, ANOVA e teste de Tukey, ao nível de significância de 1%. Resultados e conclusões: Com relação à associação da resina + fibra na posição (A, observou-se a maior média de níveis de cinza para a resina pura, seguido por resina + Connect, resina + Interlig (que não diferiram entre si, e resina + Ribbond. Com relação à associação da resina + fibra na posição (B, observou-se que a resina pura apresentou maior média, seguida por resina + Connect, resina + Interlig e resina + Ribbond, sendo que as duas últimas não foram diferentes entre si. Os resultados sugerem que os níveis de cinza variaram em função do tipo de fibra de reforço e da posição na radiografia

O Uso de Resina de Poliéster em Trabalho de Campo para Recobrir Espécimes Fragmentados

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Helder de Paula

2005-01-01

Full Text Available Freqüentemente, fósseis de vertebrados são encontrados como partes de esqueletos erodidos superficialmente. Em vários casos, os ossos estão demasiadamente danificados para suportar os estresses decorrentes das etapas de coleta e transporte. Não é incomum o fato de fósseis nesta situação serem deixados no campo ou mesmo serem perdidos devido a sua fragilidade. Aqui, descrevemos um simples procedimento que pode ser utilizado no campo para recobrir fósseis danificados. Aplicamos este procedimento com grande sucesso no fêmur de um dinossauro saurópoda coletado no sítio Confusão (município de Tesouro, uma localidade recentemente descoberta no estado do Mato Grosso. O material é preservado numa matriz conglometrática correlacionável com o Grupo Bauru. O fêmur (MN 6813-V possui aproximadamente 110 cm de largura e tinha a metade distal parcialmente exposta devido as periódicas enchentes do rio Confusão. Ele possui uma Saliên cia lateral bem desenvolvida a qual é considerada como uma característica titanossauriforme. A porção distal, incluindo a articulação, estava preservada principalmente como uma impressão na rocha, juntamente com alguns fragmentos da parte mais cortical do osso. Esta porção do fêmur estava demasiadamente friável para ser coletada como uma peça única. Após uma limpeza geral da superficie, recobrimos as porções mais frágeis da parte distal do fêmur (incluindo as impressões com diversas camadas finas de resina de poliéster que foram gentilmente aplicadas com um pincel. Usamos 0,75% de metil etil cetona (MEK como catalisador para a resina de poliéster e esperamos até que cada camada de resina secasse lentamente. Na seqüência, uma camada mais espessa de resina com gaze foi utilizada para fazer esta região mais resistente e forte o bastante para se manter por si só. As demais partes do processo de coleta seguiram os procedimentos tradicionais incluindo o uso de uma jaqueta de gesso. Entre os

Polymerization shrinkage evaluation of three packable composite resins using a gas pycnometer Avaliação da contração de polimerização de três resinas compactáveis, medida por picnômetro a gás

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Ricardo Amore

2003-09-01

Full Text Available Modern restorative dentistry has been playing an outstanding role lately since composite resins, allied to adhesive systems, have been widely applied on anterior and posterior teeth restorations. The evolution of composite resins has mostly been verified due to the improvement of their aesthetic behavior and the increase in their compressive and abrasive strengths. In spite of these developments, the polymerization shrinkage inherent to the material has been a major deficiency that, so far, has been impossible to avoid. Using a gas pycnometry, this research investigated the polymerization shrinkage of three packable composite resins: Filtek P60 (3M, Prodigy Condensable (Kerr, and SureFil (Dentsply/Caulk, varying the distance from the light source to the surface of the resins (2 mm or 10 mm. The pycnometer Accupyc 1330 (Micromeritics, USA precisely records helium displacement, allowing fast and reliable measurements of the volume of composite resin immediately before and after polymerization, without interference of temperature or humidity. Results were not found to be statistically different for the three tested resins, either for 2 mm or 10 mm-distance from the light source to the composite surface.A Odontologia Restauradora moderna tem se destacado nos últimos anos e as resinas compostas, aliadas aos sistemas adesivos, têm sido muito empregadas para restaurações de dentes anteriores e posteriores. A evolução das resinas compostas tem sido constatada na melhoria do seu comportamento estético e no aumento da sua resistência à compressão e à abrasão. Apesar dos avanços mencionados, a contração de polimerização, inerente a esse material, continua sendo uma grande deficiência e, por enquanto, impossível de ser evitada. Nesta pesquisa a contração de polimerização de três resinas compostas compactáveis, Filtek P60 (3M, Prodigy Condensável (Kerr e SureFil (Dentsply/Caulk, variando-se a distância entre a fonte de luz e a

Evaluación de resinas de intercambio iónico para el control del hierro en soluciones de electro-obtención de cobre

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Parada, F.

2010-08-01

Full Text Available Two commercial resins were evaluated for the extraction of iron from a copper electrowinning solution. Both resins efficiently extract iron. TheMonophosphonic resin has a greater charge capacity than the Diphonix resin and the Diphonix resin shows faster kinetics. Experimental results of the interrupted test and tests with different particle size of resins have demonstrated that extraction kinetics is controlled by diffusion into the particle in both resins. A good agreement with Fick’s model for diffusion inside the particles confirms the proposed mechanism. Finally, temperature favors the process kinetics and its effect on the diffusion coefficient follows Arrhenius law, obtaining a value of 4,89 kcal/mol for theMonophosphonic resin and 4,94 kcal/mol for the Dphonix resin. The aforementioned values are close to typical values for the proposed diffusional control which are 6 to 10 kcal/mol.

Se evaluaron dos resinas comerciales para la extracción del hierro desde una solución de electro-obtención de cobre. Ambas resinas extraen en forma eficiente el hierro, pero se diferencian en que la resina Monophosphonic tiene una mayor capacidad de carga que la resina Diphonix, mientras que la Diphonix muestra una cinética más rápida. Los resultados de la prueba interrumpida y de las pruebas para determinar el efecto del tamaño de partícula permiten concluir que el control más probable para la cinética de extracción es por la difusión en la partícula en ambas resinas. Un buen ajuste al modelo de Fick para difusión en la partícula confirman el tipo de control propuesto. Finalmente, la temperatura favorece la cinética del proceso de extracción y su efecto en el coeficiente de difusión sigue la ley de Arrhenius obteniendo un valor para la energía de activación de 4,89 kcal/mol para la resina Monophosphonic y 4,94 kcal/mol para la resina Diphonix. Estos valores están cercanos al valor típico para el control propuesto que es de 6 a

Estudo de resistência à tração de três sistemas adesivos associados a resina composta em superfícies dentinárias

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MATOS Adriana Bona

2001-01-01

Full Text Available Este trabalho teve como objetivo comparar a resistência à tração de três sistemas adesivos associados a resina composta aderidos à superfície dentinária. Quarenta e cinco superfícies de dentina foram obtidas a partir de molares humanos extraídos, sobre elas foi preparado "smear layer" e foram divididas em 3 grupos: G1 adesivo autocondicionante + resina micro-híbrida; G2 adesivo de componente único + ácido e resina micro-híbrida e G3 adesivo convencional (ácido + "primer" + bond + resina micro-híbrida, aplicados de acordo com as instruções dos fabricantes. Os corpos-de-prova foram preparados para teste de tração, imersos em água destilada por 24 horas a 37ºC. Findo este tempo, o teste de tração foi realizado em máquina de ensaio Inströn com velocidade constante de 0,5 mm/min. Os resultados foram expressos em MPa e submetidos a análise de variância (p < 0,05. Os autores concluíram que: o tipo de sistema adesivo influenciou na resistência à tração das resinas compostas testadas; o sistema adesivo de componente único apresentou os melhores resultados de resistência adesiva.

Avaliação das propriedades elétricas de barras estatóricas fabricadas com resina do tipo éter diglicidílico do bisfenol F (DGEBF contendo nanopartículas de silica

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Rafael Novaes da Conceição

Full Text Available Resumo O presente trabalho visa apresentar resultados da aplicação de uma resina epóxi bisfenólica (DGEBF à base de nanopartículas de sílica (RN e comparar suas propriedades com a resina convencional de referência epóxi bisfenólica (DGEBA (RE, atualmente utilizada. Neste sentido fabricaram-se protótipos de barras estatórica, destinadas a hidrogeradores, através do sistema VPI (Vácuo-Pressão-Impregnação e avaliaram-se as propriedades elétricas pelas técnicas de fator de dissipação e envelhecimento acelerado. Dentre os resultados para as resinas observou-se que: (i o fator de dissipação e de envelhecimento são praticamente os mesmos para ambas as resinas; (ii o valor de tip-up resultaram em 0,014% para RE e 0,020% para a resina RN e (iii a estimativa do tempo de vida útil esta em cerca de 40 anos, o que é aplicável para a maioria das aplicações industriais. Neste sentido sugere-se que a resina RN pode ser uma alternativa a resina RE, com um desempenho elétrico equivalente.

Influência do tempo de fotopolimerização de diferentes resinas compostas na sorpção de água = Influence of polymerization time of different composites on water sorption

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Guimarães, Fabrício Barbosa Rocha

2008-01-01

Full Text Available Objetivo: Verificar a influência do tempo de polimerização de resinas compostas na absorção de água por diferentes resinas compostas. Metodologia: As resinas multiuso Z250®, compactável P60® e de micropartículas A110® foram utilizadas para a confecção de corpos-de-prova (n=5 por grupo de acordo com o tempo de fotopolimerização (o indicado pelo fabricante, a metade e o dobro do tempo preconizado. A quantidade de água absorvida pelos espécimes foi medida pela variação da massa dos mesmos, que foram pesados imediatamente após sua confecção, a cada 24h por 10 dias, e após 15 e 30 dias. Os dados foram analisados por ANOVA e teste de Tukey. Resultados: A absorção de água das resinas compostas foi diferente quando o tempo de polimerização foi alterado. A resina de micropartículas teve o melhor comportamento perante a mudança no tempo de fotopolimerização, enquanto que a resina de multiuso foi a que mais absorveu água quando o tempo foi alterado para menos (P<0,05. Conclusão: O tempo de polimerização sugerido pelo fabricante deve ser respeitado para assegurar a manutenção das propriedades desses materiais, independentemente do tipo de resina utilizado

Atenuação da intensidade de luz e profundidade de polimerização de resinas compostas

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Werlang, Jean Felipe Garlet; Dalfovo, Ricardo João; Neiva, Ivana Froede; Obici, Andresa Carla

2016-01-01

Objetivo: Avaliar a atenuação da luz através de diferentes espessuras de resina composta e a profundidade de polimerização. Materiais e Métodos: Foram utilizadas as resinas Opallis e Llis de esmalte (E) e de dentina (D), na cor A3. Para atenuação da luz foram empregadas matrizes metálicas (6,0mm de diâmetro e espessuras de 0,5, 1,0, 1,5 e 2,0mm), as quais foram posicionadas na janela de leitura do radiômetro e a intensidade de luz medida antes e após a interposição do material. A profundidade...

Intensidade de fluorescência em resina composta: influência do polimento superficial e dos meios de armazenagem

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Ângela Dalla Nora

Full Text Available INTRODUÇÃO: A resina composta é um material versátil em Odontologia Estética, principalmente por suas propriedades ópticas, dentre as quais a fluorescência. Poucos são os estudos que avaliaram esta propriedade e a comparação dos resultados encontrados torna-se difícil em função da inexistência de padronização nas metodologias na confecção e na armazenagem dos corpos de prova. OBJETIVO: Verificar a influência do polimento superficial e do meio de armazenagem, em estudos in vitro, em que se avalia a propriedade óptica de fluorescência em resinas compostas. MATERIAL E MÉTODO: Foram preparados 70 corpos de prova circulares (10 mm × 2 mm com resina composta microhíbrida (Opallis,- A2E - FGM. Os meios de armazenagem foram: água deionizada, água da torneira e saliva artificial. Os protocolos de polimento superficial, realizados em politriz após a obtenção dos corpos de prova, utilizaram lixas de granulações 600, 1200 e 2500. Os valores de intensidade de fluorescência foram avaliados através do espectrofotômetro Cary Eclipse, após 1, 7 e 21 dias. RESULTADO: Não houve diferença estatisticamente significativa na Intensidade de Fluorescência entre os grupos submetidos aos diferentes protocolos de polimento. Quanto aos meios de armazenagem, a partir do sétimo dia, a variação de fluorescência foi significativamente maior em água da torneira e deionizada, quando comparada à variação observada em saliva artificial, resultado que se manteve após 21 dias. CONCLUSÃO: O protocolo de polimento superficial não promoveu alterações significativas na fluorescência da resina composta avaliada. Quanto ao meio de armazenagem, a intensidade de fluorescência foi menos afetada quando em saliva artificial.

Avaliação da toxicidade aguda e potencial neurotóxico do óleo-resina de copaíba (Copaifera reticulata Ducke, Fabaceae

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Camile Giaretta Sachetti

Full Text Available O óleo-resina de copaíba obtido do gênero Copaifera L., Fabaceae, é largamente utilizado na medicina popular como antiinflamatório, antimicrobiano e antitumoral. Porém, informações sobre seu potencial tóxico são escassos na literatura. O objetivo deste estudo foi estabelecer a toxicidade oral aguda e os possíveis efeitos neurotóxicos relacionados à ingestão do óleo-resina de Copaifera reticulata Ducke, Fabaceae, em ratas Wistar. O estudo foi conduzido com quinze ratas nulíparas distribuídas nos grupos de doses 300 e 2000 mg/kg pc de óleo-resina administrado por gavagem. Os resultados obtidos mostraram que nestas doses não houve sinais clínicos de toxicidade ou neurotoxicidade, alteração no consumo de ração ou alteração no peso corpóreo. A dose letal aguda foi estimada como maior que 2000 mg/kg pc e classificada como categoria 5, segundo o Guia OECD 423. Estes resultados indicam que existe uma relativa margem de segurança para o uso do óleo-resina de copaíba como agente terapêutico, embora estudos toxicológicos adicionais sejam ainda necessários, principalmente com a administração repetida de baixas doses.

La oración compuesta en guambiano

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1994-01-01

Full Text Available L'ÉNONCÉ COMPLEXE EN GUAMBIANO. Le document est divisé en deux parties. La première partie, à titre d'introduction illustrative présente une synthèse générale de l'énoncé simple en Guambiano. La deuxième partie développe le thème central de l'article : l'énoncé complexe. Les différentes classes d'énoncés sont présentées dans l'ordre, les énoncés complexes par juxtaposition, par coordination par subordination. El documento está organizado en dos partes. En la primera, a manera de introducción ilustrativa, se hace una síntesis general sobre la oración simple en guambiano. En la segunda se desarrolla el tema objeto del artículo: la oración compuesta. En él se presentan las diferentes clases de oraciones complejas identificadas hasta el momento en su orden: oraciones yuxtapuestas, coordinadas y subordinadas. THE COMPOUND SENTENCE IN GUAMBIANO. The document is organized in two parts. In the first, as an introductive illustration, a general synthesis of the simple sentence in Guambiano is done. In the second, the core theme of the article is developed: the compound sentence. There, the different kinds of complex sentences identified up to the moment are presented. They are in their order: juxtaposed, coordinated and subordinated sentences.

RESINAS COMPOSTAS EM DENTES POSTERIORES: UMA REVISÃO SISTEMÁTICA

OpenAIRE

Lima, Cláudia Fonseca de Albuquerque; de Souza, Fábio Barbosa; da Silva, Claudio Heliomar Vicente

2016-01-01

As resinas compostas vêm sendo largamente utilizadas em dentes posteriores. Objetivou-se realizar uma revisão sistemática acerca das publicações de avaliações clínicas do emprego deste material em restaurações que envolvessem a superfície oclusal e/ou proximal de pré-molares e molares de forma a avaliar os critérios empregados para execução das mesmas. As publicações foram selecionadas aleatoriamente a partir de uma pesquisa bibliográfica a partir dos pré-requisitos: publicação em revista ind...

Rugosidade e microscopia de força atômica de resinas compostas submetidas a diferentes métodos de polimento

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Larissa Márcia Martins Alves

2013-01-01

Full Text Available Este trabalho avaliou a rugosidade e a topografia de superfície de resinas compostas submetidas a diferentes métodos de polimento. Foram utilizadas 5 resinas (Filtek Z350, Master Fill, Vênus, Charisma e Durafill VS e confeccionou-se 90 corpos de prova distribuídos em 6 grupos (n:15: SP: sem polimento; TB: ponta de borracha abrasiva; DL: disco de lixa em três granulações; FP: disco de feltro com pasta diamantada; ECS: escova de carbeto de silício; PS: ponta de silicone abrasiva. Após os polimentos, foram realizadas as análises da rugosidade com auxílio de um rugosímetro e da topografia de superfície com a microscopia de força atômica. Os valores foram tabulados e analisados estatisticamente pelos testes de Kruskal-Wallis, DUNN e ANOVA (α = 0,05. As médias variaram entre 0,01 µm (Filtek Z 350 - TB e 0,27 µm (Charisma - ECS. Concluiu-se que para todas as resinas testadas o melhor método de polimento foi o feltro com pasta diamantada (FP.

Avaliação in vitro da atividade antibacteriana de um cimento odontológico à base de óleo-resina de Copaifera multijuga Hayne

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Kátia Regina Felizardo Vasconcelos

Full Text Available Um dos materiais utilizados para a adequação do meio bucal no serviço público é o cimento produzido a partir de óxido de zinco e eugenol. Entretanto, o eugenol é uma substância citotóxica que pode desencadear alguns efeitos adversos. Por essa razão, procura-se substituir o eugenol por uma substância que apresente baixa toxicidade, mantendo ou mesmo melhorando as propriedades do cimento. O óleo-resina de copaíba é um produto natural, utilizado pelas populações amazônicas e reconhecido por suas propriedades medicinais. Baseando-se nas propriedades desse óleo-resina, na ação antimicrobiana comprovada do hidróxido de cálcio e na ação anti-séptica do óxido de zinco, propôs-se formular um cimento odontológico obtido da associação do ZnO, Ca(OH2 e óleo-resina de Copaifera multijuga Hayne e avaliar sua atividade antibacteriana através do teste de diluição em meio líquido frente às cepas padrão de Streptococcus mutans (ATCC 25175 e S. sanguinis (ATCC 15300. Nesse ensaio, utilizaram-se os seguintes grupos experimentais: o cimento contendo ZnO, Ca(OH2 e óleo-resina de copaíba (G1 e cada um dos constituintes isoladamente, ZnO (G2, Ca(OH2 (G3 e óleo-resina de copaíba (G4. Todos os grupos analisados demonstraram atividade antibacteriana, o G4 apresentou os melhores resultados e o G1 mostrou-se um cimento promissor a ser utilizado em odontologia.

EFECTO DE LOS OBSTÁCULOS TIPO POLIMERO RESINA EN RENDIMIENTO DE REDES TCP/IP/IEEE 802.11g MODO AD-HOC

OpenAIRE

Márquez Barriobero, David

2011-01-01

La investigación tiene como objetivo primordial el desarrollo de un modelo matemático para evaluar el efecto de los obstáculos de tipo polímero resina en el rendimiento de redes TCP/IP/IEEE 802.11g modo ad-hoc; esto con el propósito de establecer la relación existente entre el diámetro de los obstáculos de tipo polímero resina y el rendimiento de una red inalámbrica en modo ad-hoc, al transmitir datos vía protocolo FTP. El tipo de investigación es explicativa con un diseño experimental. Los t...

Avaliação em curto e médio prazo da sorção e da solubilidade de resinas compostas à base de metacrilato e de silorano em saliva artificial

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Isabel Cristina Celerino de Moraes Porto

Full Text Available INTRODUÇÃO: A absorção/adsorção de moléculas de água por monômeros hidrofílicos dentro de materiais resinosos expostos à umidade da boca pode resultar em degradação. OBJETIVO: Este estudo avaliou sorção e solubilidade de resinas compostas à base de metacrilato e silorano em contato com saliva artificial, nos períodos de um dia (curto prazo, e 30 e 90 dias (médio prazo. MATERIAL E MÉTODO: Sessenta corpos de prova foram confeccionados com as resinas Filtek® Z250 e Filtek® P90 Silorano (3M/ESPE, e depois imersos em saliva artificial a 37 ± 1 ºC durante um, 30 e 90 dias. Os dados foram analisados usando-se ANOVA um fator/dois fatores seguido dos testes Tukey ou Tamhane (α = 0,05. RESULTADO: As médias de sorção das duas resinas aumentaram com o tempo (p = 0,001. A sorção de Z250 (1 e 90 d foi significativamente maior do que de P90 (p = 0,008, com valores semelhantes após 30 dias. A solubilidade das resinas também aumentou com o tempo, com diferença significativa entre todos os períodos (p = 0,001, exceto para a resina P90 (entre 1 e 30 d. Não houve diferença estatística significante entre os grupos Z250 (1 d e P90 (1 dia, Z250 (1 d e P90 (30 d, e Z250 (30 d e P90 (90 d. Para os demais pares, comprovaram-se diferenças significativas (p < 0,001. CONCLUSÃO: As propriedades de sorção e solubilidade das resinas compostas testadas foram influenciadas pelo tempo de exposição à saliva artificial. O silorano teve desempenho ora melhor ora semelhante à resina de metacrilato.

Resinas acetálicas: diversas aplicaciones en odontoestomatología

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Puigpelat Martí, Ana M.; Casanellas Bassols, Josep M. (Josep Maria)

1994-01-01

La resina acetálica o Polioxime­tileno (POM) es un nuevo material estético de reciente aplicación en el campo de la Odontoestomatolo­gía. En este artículo presentamos al­gunas de las aplicaciones donde la estética desempeña una función importante. Una de las aplicaciones de las re­sinas acetálicas es el campo de la Prótesis Parcial Removible, cuan­do queremos sustituir los retene­dores vestibulares convencionales (metálicos) por retenedores más es­téticos. Otra posible aplicación puede ser la...

TRATAMENTO DA CASCA DE QUEIJO CANASTRA COM RESINA E SEUS EFEITOS DURANTE A MATURAÇÃO E NA QUALIDADE COMO FORMA DE MELHORAR O ASPECTO E AGREGAR VALOR AO PRODUTO

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Paulo Henrique Costa Paiva

2012-08-01

Full Text Available O principal objetivo deste trabalho foi testar uma alternativa para melhorar o aspecto de apresentação e a qualidade do queijo Minas artesanal da Canastra sem comprometer as suas características peculiares. Assim, foram comparados queijos Minas artesanais da Canastra ao longo da maturação com aplicação de resina de grau alimentar na casca em relação àqueles sem aplicação, quanto aos aspectos físico-químicos, microbiológicos e sensoriais, durante as quatro estações do ano. Nos ensaios preliminares foram definidas a forma de aplicação (emprego das mãos e a quantidade (5 g de resina pura/unidade de queijo, sem necessidade da adição de sorbato de potássio. Durante o período de maturação estudado (2, 15, 30 e 45 dias não observou-se diferença significativa entre os queijos com e sem aplicação de resina na casca em relação às características físico-químicas como pH, atividade de água, teor de umidade, teor de gordura no extrato seco, extensão e profundidade de proteólise. E aos 15 e 30 dias de maturação, a Análise Descritiva Quantitativa Modificada (ADQM não indicou diferença entre os tratamentos com e sem aplicação de resina quanto aos atributos sensoriais avaliados, exceto para o aspecto global após 15 dias. Os queijos com aplicação de resina na casca tiveram um escore referente ao aspecto global maior em relação àqueles sem aplicação, após 15 dias de maturação, devido ao menor crescimento de mofos durante esse período. A partir dos escores obtidos no teste de aceitação mediante o uso de escala hedônica de 9 pontos, também não houve diferença significativa entre os queijos com e sem aplicação de resina na casca durante as quatro estações do ano. Entretanto, observou-se diferenças significativas nos queijos ao longo do ano, em relação às características físico-químicas pH, teor de gordura no extrato seco e profundidade de proteólise, e em relação aos atributos sensoriais

Biodetoxification of toxins generated from lignocellulose pretreatment using a newly isolated fungus, Amorphotheca resinae ZN1, and the consequent ethanol fermentation

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Wang Wei

2010-11-01

Full Text Available Abstract Background Degradation of the toxic compounds generated in the harsh pretreatment of lignocellulose is an inevitable step in reducing the toxin level for conducting practical enzymatic hydrolysis and ethanol fermentation processes. Various detoxification methods have been tried and many negative outcomes were found using these methods, such as the massive freshwater usage and wastewater generation, loss of the fine lignocellulose particles and fermentative sugars and incomplete removal of inhibitors. An alternate method, biodetoxification, which degrades the toxins as part of their normal metabolism, was considered a promising option for the removal of toxins without causing the above problems. Results A kerosene fungus strain, Amorphotheca resinae ZN1, was isolated from the microbial community growing on the pretreated corn stover material. The degradation of the toxins as well as the lignocelluloses-derived sugars was characterized in different ways, and the results show that A. resinae ZN1 utilized each of these toxins and sugars as the sole carbon sources efficiently and grew quickly on the toxins. It was found that the solid-state culture of A. resinae ZN1 on various pretreated lignocellulose feedstocks such as corn stover, wheat straw, rice straw, cotton stalk and rape straw degraded all kinds of toxins quickly and efficiently. The consequent simultaneous saccharification and ethanol fermentation was performed at the 30% (wt/wt solid loading of the detoxified lignocellulosic feedstocks without a sterilization step, and the ethanol titer in the fermentation broth reached above 40 g/L using food crop residues as feedstocks. Conclusions The advantages of the present biodetoxification by A. resinae ZN1 over the known detoxification methods include zero energy input, zero wastewater generation, complete toxin degradation, processing on solid pretreated material, no need for sterilization and a wide lignocellulose feedstock spectrum

Avaliação das características da resina epóxi com diferentes aditivos desaerantes

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Alexsandro Oliveira

2015-04-01

Full Text Available Este trabalho tem por objetivo a busca por técnicas alternativas para diminuir a incidência de vazios em resinas poliméricas e, por consequência, em materiais compósitos. Foram produzidas formulações diferentes utilizando resina epóxi à base de éter diglicidílico do Bisfenol A, endurecedor de poliamina alifática com e sem a adição de diferentes aditivos desaerantes a base de éteres e ésteres modificados. As formulações produzidas foram submetidas a condições extremas de agitação e processamento, sendo posteriormente avaliadas quanto a incidência de bolhas e vazios, densidade, propriedades mecânicas, morfológicas e térmicas. Os resultados foram bastante positivos quanto à diminuição da quantidade e do tamanho de poros pela utilização de técnicas de desgaseificação a vácuo e pelo uso de aditivos desaerantes.

Resistência à microtração entre uma cerâmica hidrotérmica, silanizada ou não, aderida à uma resina composta por um cimento resinoso

OpenAIRE

Lopes, Angela; Leite, Fabiola; Valandro, Luis Felipe; Siqueira, Luciana; Pimenta, Luiz André; Neisser, Maximiliano Piero

2010-01-01

Esse trabalho teve como objetivo avaliar a resistência adesiva entre uma cerâmica hidrotérmica (Symbio ceram, Degussa), silanizada ou não e aderida à uma resina composta (Filtec Z100- 3M ESPE) por um cimento resinoso (Panavia F, Kuraray). Foram confeccionados 2 blocos, divididos em 2 grupos assim constituídos: Grupo I-tratamento de superfície da cerâmica com ácido fluorídrico a 10% e união a um substrato (resina compost...

Síntesis intermatricial y comparación de nanopartículas metálicas de Pd y Co soportadas en resinas catiónicas y aniónicas

OpenAIRE

Bastos Arrieta, Julio; Universitat Autònoma de Barcelona. Departament de Química

2010-01-01

Esta memoria de investigación es producto del trabajo experimental que se realizó con resinas de intercambio iónico para la síntesis intermatricial de nanopartículas metálicas de Co y Pd. Los estudios que se realizaron correspondieron a la iniciación en esta modalidad de síntesis de nanopartículas. En ellos se contemplaron las propiedades intrínsecas de la resina como: la capacidad de intercambio iónico, y funcionalidad química, tanto antes como después de la síntesis. Uno de los objetivos...

Knoop hardness of enamel and shear bond strength of brackets bonded with composite resin with and without fluoride Dureza Knoop do esmalte e resistência ao cisalhamento de braquetes colados com resina composta com e sem flúor

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Silvia Amélia Scudeler Vedovello

2012-08-01

Full Text Available OBJECTIVE: The aim of this study was to evaluate the Knoop hardness of enamel, shear bond strength and failure pattern (adhesive, bracket/resin interface or mixed after bonding and debonding brackets, using resin composite with fluoride (Ortho Lite Cure, Ortho Source® and without fluoride (Orthobond, Morelli®. METHODS: Fragments (6 mm x 6 mm of 40 bovine incisor crowns were embedded in acrylic self-polymerizing resin. The Knoop hardness measurements were performed before and after bonding metal brackets. The specimens were divided into two groups, according to composite resin: with fluoride (Ortho Lite Cure, Ortho Source® and without fluoride (Orthobond, Morelli®. After bonding, the specimens were submitted to demineralization and remineralization cycling for 14 days. Shear bond strength testing was performed in a universal test machine (EMIC, at 5 mm/min crosshead speed. RESULTS: There was no significant difference in shear bond strength between Groups I and II. After demineralization and remineralization procedures (DE/RE, the specimens bonded with Ortho Lite Cure showed higher Knoop hardness than Orthobond. For both groups there was predominance of failure at bracket/resin interface. CONCLUSION: specimens bonded with fluoride resin composite showed higher microhardness after DE/RE cycling than those bonded with resin composite without fluoride, although no difference in shear bond strength was found.OBJETIVO: o propósito deste estudo foi avaliar a dureza Knoop do esmalte, resistência ao cisalhamento e padrão de falha (adesiva; interface braquete/resina; e mista após a colagem e descolagem de braquetes, utilizando uma resina composta com flúor (Ortho Lite Cure, Ortho Source® e uma sem flúor (Orthobond, Morelli®. MÉTODOS: fragmentos (6mm x 6mm de 40 coroas de incisivos bovinos foram embutidos em resina acrílica autopolimerizável. A dureza Knoop foi avaliada antes e após a colagem dos braquetes metálicos. Os corpos de prova

Obtención de nano-estructuras bi-dimensionales de SnO2 utilizando el método pechini: estudio de la conformación de la resina

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Rodriguez Paez, J. E.

2008-10-01

Full Text Available Pechini method has been widely used in the synthesis of oxides, but the physicochemical process that happens during this one have not been discussed in detail, for example the resin conformation that is obtained in one of the stages of the process. Knowing the resin evolution and since the most important parameter of this one are modified, it could determinate the most appropriate conditions to conform thin films though the Pechini method. In this work the resin evolution of the tin system considering parameters like pH, viscosity, time and temperature of heating were studied. Infrared spectroscopy (FTIR and viscosity measures in differents steps of the process were used. The IR spectroscopy results shows that as it advances the aging time of the resin, to a temperature between 80 and 100ºC and a pH of 6,5, Sn-O bonds are strengthen. Films were conformed with the resin obtained during the pechini process, it being defined a value of 110cP as the most appropriate to favor the homogeneity and adherence of this ones. The grain size film was of ∼110nm what indicates that the realized process allows to obtain bidimensional nano-structures.A pesar que el método de precursor polimérico, Pechini es ampliamente utilizado en la síntesis de óxidos, los procesos fisicoquímicos que ocurren durante el mismo no se han discutido en detalle; tal es el caso de la conformación de la resina que se obtiene en una de las etapas del proceso. Conociendo la evolución de esta resina, y como se modifican los parámetros más importantes de la misma, se podrían determinar las condiciones más adecuadas para conformar películas delgadas a través de este método. En este trabajo se estudio la evolución de la resina del sistema de estaño considerando parámetros como pH, viscosidad, tiempo y temperatura de calentamiento de la misma. Para este estudio se utilizó espectroscopía infrarroja (FTIR y medidas de viscosidad de la resina en diferentes instantes del

Complejación de la resina de intercambio de iones: enmascaramiento del sabor amargo de cefuroxime acetil Ion-exchange resin complexation: Masking the bitter taste of cefuroxime axetil

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Inderbir Singh

2011-06-01

Full Text Available OBJECTIVE: the purpose of this research was to formulate taste masked complexes of cefuroxime axetil and to evaluate them for taste, drug loading and characterized by FTIR, XRD. Tablets were formulated of selected batches and evaluated for drug release and physical parameters. METHODS: complexation technique is used to prepare complexes of drug where ion exchange resins such as Indion® 214, Indion® 234 and Indion® 414 were used with a drug-resin ratio of 1:0.5, 1:1, 1:2. The drug resinates were characterized by Infrared Spectroscopy, DSC and X-Ray Diffraction pattern and evaluated for drug loading and taste. Direct compression method was used to formulate tablets. In vitro dissolution was carried out using USP II apparatus. RESULT: potential taste masking increased with increasing concentration of resin. Indion® 214 resin showed better taste masking effect as compared to Indion® 234 and Indion® 414. Percent of drug loading was maximum at drug : resin ratio of 1:1, after that it decreased. Prolonged (upto 5 h and slow drug release was observed with resin 214 at higher concentration. CONCLUSIONS: out of three resins chosen, Indion® 214 at higher concentration exhibit excellent taste masking as well as sustained drug release action.OBJETIVO: el objetivo de esta investigación fue formular los complejos con sabor amargo de cefuroxime acetil y evaluarlos por sabor, carga medicamentosa y caracterización por FTIR, XRD. Las tabletas fueron formuladas a partir de lotes seleccionados y evaluados en busca de la liberación medicamentosa y parámetros físicos. MÉTODOS: la técnica de complejación se utilizó para preparar complejos farmacológicos donde las resinas de intercambio iónico como Indion® 214, Indion® 234 y el Indion® 414 se emplearon a una proporción resina-medicamento de 1:0.5, 1:1, 1:2. Los resinados medicamentosos fueron caracterizados mediante espectroscopia infrarroja, DSC y el patrón de difracción-rayos-X, y evaluados

Análise de custo de materiais utilizados em restaurações dentárias em resina composta

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Eduardo Hebling

Full Text Available INTRODUÇÃO: As resinas compostas são materiais usualmente utilizados em restaurações dentárias diretas de dentes posteriores. O custo dos materiais faz parte do cálculo do valor dos honorários odontológicos. OBJETIVO: O objetivo deste trabalho foi determinar e analisar o valor total do custo dos materiais utilizados para a confecção de restaurações dentárias diretas de dentes posteriores em resina composta. MATERIAL E MÉTODO: O cálculo dos custos foi baseado no método de sistema de custeio variável. A lista dos materiais foi obtida por meio de consulta a uma banca de juízes e baseada nos padrões de excelência comprovados na literatura para atendimento em equipe. Os valores dos materiais foram obtidos de uma média dos valores consultados no mercado fornecedor. As repetições foram obtidas de preparos cavitários Classes I e II em dentes pré-molares e molares artificiais pré-fabricados. Os materiais foram quantificados para cada tipo de preparo. As resinas compostas utilizadas foram pesadas em balança de precisão após a sua inserção em cada tipo de preparo. Os dados foram avaliados por estatística descritiva e pelos testes de Mann-Whitney e Kruskal-Wallis. RESULTADO: O custo encontrado para restauração de Classe I foi de R$17,56 e, para a de Classe II, de R$17,73. Não houve diferença estatística no custo entre os tipos de preparo e de dentes, sendo a média total de R$17,65. CONCLUSÃO: Os valores encontrados podem ser utilizados no cálculo do valor final do procedimento restaurador, auxiliando na gestão de serviços odontológicos públicos ou privados.

Lograr estética y función en el sector posterior con resinas compuestas

OpenAIRE

García Crimi, Graciela Edith

2014-01-01

La operatoria dental actual cuenta con un conocimiento más profundo de las diferentes estructuras dentarias que sumado al gran adelanto tecnológico y científico en la ciencia de los biomateriales; fruto de innumerables investigaciones, nos permiten contar hoy, con una nueva generación de materiales restauradores, lo que hace más crítico y exigente el conocimiento y análisis por parte del profesional, de las técnicas a efectuar, la realización depurada de procedimientos y l...

Resistência à compressão entre uma resina composta direta e dois cerômeros = Resistence of compression between a direct composite resin and two “cerômeros”

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Gouvêa, Cresus Vinícius Depes de

2007-01-01

Full Text Available Esse estudo avaliou a resistência à fratura de duas resinas laboratoriais que se encontram no mercado, a Artglass® e a Targis® e como grupo comparador, a resina composta direta TPH®. Foram utilizados cinco corpos de prova de cada resina a ser testada. Com o auxílio de matrizes em aço inoxidável com forma de um cone segmentado, com medidas internas de 8,0 mm de diâmetro na base, 9,0 mm na porção superior e 4,0 mm de altura, foram confeccionados os corpos de prova. As amostras foram mantidas em água destilada por 72 horas e submetidas a uma carga axial por ação de uma ponta de extremidade arredondada de 2 mm diâmetro, adaptada a uma máquina de teste universal EMIC 500. A velocidade foi de 0,5 mm/min, com uma célula de capacidade de carga de 200 kgf. A carga e o ponto de fratura foram registrados na máquina. As médias foram calculadas em kgf, sendo o Artglass® apresentando A = 223,46; Targis® T = 204,13; TPH® Tp = 98,26. Os dados foram submetidos à análise estatística. Observou-se que a resina TPH obteve significativamente menor resistência à compressão enquanto Targis e Artiglass não apresentaram diferença estaticamente significativamente entre si; o conteúdo de carga inorgânica influencia positivamente na resistência à compressão

Comparação dos valores de desgaste abrasivo e de microdureza de 13 resinas compostas usadas em odontologia através do método do disco retificado

OpenAIRE

Bianchi,Eduardo C.; Aguiar,Paulo R. de; Alves,Manoel C. S.; Freitas,César A. de; Rodrigues,Ana R.; Carvalho Jr.,Oscar B. de

2007-01-01

Atualmente tem-se buscado simplificar a tarefa de caracterização da vida útil de restaurações dentárias realizadas por resinas compostas através de métodos laboratoriais, que são mais rápidos e não sofrem influência de variáveis pessoais inerentes às análises clínicas. Com este propósito, este trabalho apresenta uma nova metodologia de ensaio laboratorial para a avaliação do desgaste abrasivo de resinas compostas através do método do disco retificado. Realizaram-se ensaios de resistência ao d...

Evaluación de la dispersión de pigmento en resinas acrílicas para la fabricación de dientes artificiales

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Germán Ricaurte Avella

2010-01-01

Full Text Available En la primera etapa de fabricación de dientes artificiales los pigmentos se dispersan en seco en un polvo de resina acrílica conformado por finas partículas esféricas. Esta dispersión tiene características especiales diferentes a la dispersión de pigmentos en resinas líquidas usual en el campo de las pinturas y recubrimientos o en la fabricación de plásticos. No hay muchos reportes sobre los métodos de análisis y control de este tipo de procesos. En este trabajo se pretende evaluar el método de poder colorante, usual en la industria de recubrimientos, contrastando sus resultados con el porcentaje de área de pigmento adherida a las esferas de resina aplicando técnicas de procesamiento digital de imágenes (PDI a micrografías SEM. Se proponen y discuten, además, otros tres métodos alternativos basados en análisis de curvas de reflectancia, que permiten una evaluación rápida del proceso de dispersión, e incluso determinar el valor de la energía de la banda prohibida del pigmento. El método de poder colorante resulta ser el más sensible a las diferencias de dispersión. Finalmente, se aplican los cuatro métodos a una comparación entre tres procesos de molienda con diferentes energías y se discuten los resultados y las limitaciones de cada uno.

Avaliação do monômero residual de resinas acrílicas utilizadas para prótese ocular, polimerizadas convencionalmente e por energia de microondas = Evaluation of residual monomer between conventional and microwave heat-cured acrylic resins used for ocular prostheses

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Moroni, Pedro Alexandre

2005-01-01

Full Text Available Este trabalho objetivou comparar a quantidade de monômero residual das resinas acrílicas utilizadas para confecção de prótese ocular, termopolimerizável incolor (grupo controle e Onda-Cryll incolor após a polimerização convencional (MC e com energia de microondas (MW respectivamente. Para o experimento foram confeccionados três corpos-de-prova para cada tipo de resina e período de investigação, num total de 30 corpos-de-prova, os quais foram submetidos a ensaios titulométricos nos períodos de 5, 30 60, 120 e 1. 440 minutos (24 horas após a demuflagem. A resina acrílica termopolimerizável incolor apresentou índice inferiores de concentração de monômero residual em relação à resina acrílica Onda-Cryll incolor. A resina acrílica polimerizada por microondas apresentou baixos indíces de concentração de monômero residual, porém um pouco superiores (até 120 minutos em relação à resina termopolimerizável incolor. Ambos os materiais apresentaram valores numéricos estatisticamente semelhantes de concentração de monômero residual no período de 1440 minutos (24horas. Uma técnica de confecção de prótese ocular através de forno de microondas é exeqüível, pois os acrílicos apresentam concentrações normais de monômero residual após 120 minutos da sua polimerização, em relação ao grupo controle

PRODUÇÃO DE CHAPAS DE PARTÍCULAS ORIENTADAS “OSB” DE Eucalyptus grandis COM DIFERENTES TEORES DE RESINA, PARAFINA E COMPOSIÇÃO EM CAMADAS

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Setsuo Iwakiri

2002-10-01

Full Text Available Este trabalho foi desenvolvido com o objetivo de avaliar a influência dos seguintes parâmetros de processo de produção sobre as propriedades das chapas “OSB”: composição das chapas em camadas cruzadas com proporções face-miolo-face de 30-40-30 e 20-60-20 em relação à composição homogênea; e, quantidades de 3, 4,5 e 6,0% de resina fenol-formaldeído, com incorporação de 0,5 e 1,0% de emulsão de parafina. Os resultados demonstraram que a composição das chapas, com a relação 20-60-20, apresentou melhor balanço das propriedades de flexão estática entre os sentidos de ensaios paralelo e perpendicular ao plano da chapa. A quantidade de 6,0% de resina foi a que resultou em melhores propriedades físico-mecânicas das chapas “OSB”. A produção de chapas “OSB” de Eucalyptus grandis, com 4,5 e 6,0% de resina fenol-formaldeído, superou as exigências mínimas de propriedades mecânicas das chapas “OSB” referendadas pela norma canadense CSA 0437-0 (1993.

Gradually varied flow in compound open channels; Flujo gradualmente variado en canales de seccion compuesta

Energy Technology Data Exchange (ETDEWEB)

Sotela Avila, Gilberto [Universidad Nacional Autonoma de Mexico (Mexico)

2001-03-01

The author shows that the computation of gradually-varied-flow profiles in prismatic compound channels involves the solution of the dynamic equation, but using the compound channel Froude number defined by Blalock and Sturm. The same equation is used for non-prismatic channels by dividing the channel into short reaches and carrying the computation step by step through an iterative process. [Spanish] El autor demuestra que los perfiles del flujo gradualmente variado en canales prismaticos de seccion compuesta se pueden determinar mediante la integracion de la llamada ecuacion dinamica, pero usando el numero de Froude definido por Blalock y Sturm para este tipo de canales. Cuando no son prismaticos, tambien se aplica la ecuacion de la energia por tramos y el calculo sigue un proceso iterativo una vez definidos los tirantes criticos multiples y la zona en que se desarrolla el perfil.

Condensation model for the ESBWR passive condensers

International Nuclear Information System (INIS)

Revankar, S. T.; Zhou, W.; Wolf, B.; Oh, S.

2012-01-01

In the General Electric's Economic simplified boiling water reactor (GE-ESBWR) the passive containment cooling system (PCCS) plays a major role in containment pressure control in case of an loss of coolant accident. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure following a design basis accident. There are three PCCS condensation modes depending on the containment pressurization due to coolant discharge; complete condensation, cyclic venting and flow through mode. The present work reviews the models and presents model predictive capability along with comparison with existing data from separate effects test. The condensation models in thermal hydraulics code RELAP5 are also assessed to examine its application to various flow modes of condensation. The default model in the code predicts complete condensation well, and basically is Nusselt solution. The UCB model predicts through flow well. None of condensation model in RELAP5 predict complete condensation, cyclic venting, and through flow condensation consistently. New condensation correlations are given that accurately predict all three modes of PCCS condensation. (authors)

RECICLAGEM DE PLACAS DE CIRCUITO IMPRESSO DE COMPUTADORES SUCATADOS PARA A RECUPERAÇÃO DE ESTANHO POR ELETROELUIÇÃO DE RESINAS POLIMÉRICAS DE TROCA IÔNICA

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Afonso Henriques Martins

2014-08-01

Full Text Available Este trabalho apresenta os resultados experimentais para a recuperação de estanho presente em soluções aquosas a parir da reciclagem de computadores sucatados, através da técnica de eletroeluição de resina polimérica catiônica Amberlite IR-120®(Merck, USA. A resina foi carregada pela passagem de 200ml de solução aquosa 0,2g/l de Sn em 2,18N H2SO4 (concentração do licor de lixiviação de placas de circuito impresso-PCI de microcomputadores sucatados através do leito de 10g de resina. A realização dos experimentos foi baseada em um planejamento estatístico pelo método fatorial completo replicado de três variáveis a dois níveis. A otimização foi feita pelo método do passo ascendente. As condições consideradas ótimas visando a eletrorrecuperação de estanho foram 150A/m2 de densidade de corrente catódica, tempo de eletroeluição de 45 minutos e intensidade de agitação moderada do eletrólito (100rpm.

Condensers

International Nuclear Information System (INIS)

Andrieux, M.B.

1984-01-01

Characteristics of the condenser cooling waters of various French 900 MW nuclear power plants. Design and description of various types of condensers: condensers feeded directly with river water, condensers feeded by cooling towers, condensers feeded with sea water of brackish water. Presentation of the main problems encountered with the brass bundles (ammoniacal corrosion, erosion of the peripheral tubes, vibrations of the tubes), with the titanium bundles, with the tubular plates, the tubes-tubular plates assemblies, the coatings of the condenser water chamber (sea water), the vapor by-pass and with the air inlet. Analysis of the in service performances such as condensation pressure, oxygen content and availability [fr

Dermatosis profesional por resina epoxi: Presentación de un caso clínico Professional dermatosis for epoxy resin: A clinical case report

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S Gaviola

2008-06-01

Full Text Available Mostramos un caso de dermatosis profesional originado por plásticos (resinas epoxi y la importancia de la detección precoz. Las resinas epoxi son de gran utilización en todo tipo de industrias (artes graficas, construcción, electrónica, componentes de prótesis traumatológicas, prótesis odontológicas, etc. y sus componentes pueden ser causa de dermatitis de contacto irritativa y por sensibilización.We describe a case of professional dermatosis caused by exposition to plastic products (epoxy resin and importance of early detection. The epoxy resins are widely used in all types of industries (graphics arts, construction, electronics, traumathological and odontological prothesis, etc. and their components may be the cause of contact dermatitis and sensitivity. Risk factors at work with epoxy resins are present during the production base resins, hardening agents, plasticizers and dilutants increase the risk of exposition at work. This requires preventive measures and early diagnosis.

Frecuencia de restauraciones plásticas directas en dientes posteriores en tres centros públicos de Asunción

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Isolde Fischer

2015-08-01

Full Text Available En la selección del material de restauración, para rehabilitar una pieza dentaria posterior que ha sufrido una lesión, el operador puede optar entre la amalgama o la resina compuesta, equilibrando las ventajas y desventajas de cada una. Este estudio de enfoque mixto, de diseño descriptivo, retrospectivo y transversal, tuvo como objetivo determinar la frecuencia en el uso de los biomateriales restauradores en dientes posteriores. Se utilizó un cuestionario aplicado a una muestra de 164 sujetos tratados previamente en tres centros públicos de referencia en Asunción en 2.013 y 2.014. El trabajo se complementó con una técnica cualitativa, la entrevista a grupo focal, en dos grupos distintos; por un lado a docentes y por el otro, a comerciantes de artículos dentales. Se observó que la resina es el material de uso más frecuente (77,7% seguido del ionómero de vidrio (18,4%, siendo la amalgama el menos utilizado (4,2%. Docentes y comerciantes entrevistados coincidieron en opinar que la resina es el material más utilizado por el factor estético, y que la amalgama se halla francamente en desuso, sea por su falta de estética o por efectos tóxicos, aunque pocos docentes conocían los criterios actuales sobre los efectos adversos de amalgamas y resinas, emitidos por entes sanitarios internacionales. Se propone tener en cuenta estos resultados para la reorientación del curriculum en la educación odontológica respecto a los biomateriales restauradores si fuese necesario, sobre fundamentos válidos y coherentes con las necesidades del contexto.

Comportamiento de canales como conectores de cortante para un sistema de Sección compuesta usando lámina colaborante

OpenAIRE

Huertas Muñoz, Juan Carlos

2013-01-01

Las secciones compuestas de acero y concreto se emplean con el fin de aprovechar las ventajas del acero a la tensión y el buen comportamiento del concreto ante esfuerzos de compresión. Lo que permite que ambos materiales trabajen al mismo tiempo y de forma eficiente son los conectores de cortante. Para realizar la función de conector de cortante se usan elementos como los espigos, canales, varilla en forma de bastón y en forma de U, entre otros que están siendo objeto de invest...

Utilização de resinas de troca-iônica em efluentes de galvanoplastia.

OpenAIRE

Josiane Costa Riani

2008-01-01

A crescente industrialização acompanhada do uso de metais pesados nos processos industriais nas últimas décadas resultou num aumento da contaminação do meio ambiente, principalmente em ambientes aquáticos. Assim, sendo a água um recurso natural de suma importância para a vida, métodos de tratamento de efluentes tornam-se indispensáveis para empresas geradoras de efluentes. O objetivo desse trabalho é a utilização de um sistema de troca iônica constituído por micro-colunas de resinas catiônica...

Utilização de ligninas em resinas fenólicas: 1. Preparação de novolacas a partir de lignossulfonatos Use of lignins in phenolic resins: 1. Preparation of novolacs from lignosulfonates 49

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Fernando dos Santos

1999-01-01

Full Text Available Este trabalho descreve uma utilização mais nobre para a lignina obtida de processos industriais de polpação. Foram preparadas resinas fenólicas tipo novolaca, utilizando-se lignossulfonato de amônio e lignossulfonato de sódio (com diferentes teores de açúcares residuais como correagentes, em substituição parcial ao fenol. As resinas foram preparadas mantendo-se o processo utilizado industrialmente. As resinas foram caracterizadas por análises químicas, quanto à distribuição de massa molar e análises térmicas. As resinas preparadas com lignossulfonatos apresentaram maior reatividade com hexametilenotetramina (agente de reticulação. Isto é uma vantagem, pois pode-se ter ciclos de moldagem de peças mais curtos, o que economicamente é favorável.This work describes the production of high value products using lignins obtained from industrial pulping processes. Novolac phenolic resins were prepared employing ammonium lignosulfonates and sodium lignosulfonates (with different residual sugar contents in a partial replacement of phenol. The resins were prepared using the same conditions employed in the industrial phenolic resins production. The lignin based resins were characterized by chemical analysis, molecular weight distribution and thermal analysis. The resins prepared using lignosulfonates showed higher reactivity with hexamethylenetetramine (crosslink agent. This behavior lead to another economic advantage as consequence of the reduction in the expended time for molding cycles.

Avaliação em MEV da fenda resultante da contração de polimerização da resina composta aplicada sobre diferentes materiais protetores pulpares = A sem evaluation of the gap resulting from the polymerization shrinkage of composite resins applied to different pulp protective materials

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Unfer, Daniele Taís

2006-01-01

Full Text Available Introdução: A resina composta sofre contração como resultado da reação de polimerização que pode deslocar os materiais protetores pulpares, caso estes apresentem deficiente ou nenhuma adesão a dentina. Objetivo: avaliar o comportamento de dois materiais de proteção pulpar (CIV e CaOH2 cement em relação presença de fenda, quando submetidos a estresse de contração da resina composta e avaliar a fenda resultante da contração de polimerização entre dentina e resina composta. Metodologia: Foram confeccionados preparos classe V nas faces vestibular e lingual de 12 dentes molares humanos os quais foram divididos em quatro grupos de estudo, conforme a técnica restauradora e os materiais utilizados: G1 (SA + RC; G2 (HC + SA + RC; G3 (CIV + SA + RC e G4 (HC + CIV + SA + RC. Os corpos de prova foram avaliados em MEV e os dados obtidos foram submetidos análise não-paramétrica. Resultados: Os resultados obtidos mostram que os materiais de proteção pulpar utilizados são deslocados pela contração gerada pela polimerização da resina composta. Os melhores resultados (não presença de fenda foram demonstrados no grupo em que o sistema adesivo foi o único material entre a dentina e a resina composta. Quando do uso do CIV e do HC, associados ou não, foi encontrado o maior percentual de fendas. Conclusão: Os materiais de proteção pulpar continuarão a ser deslocados pela contração de polimerização das resinas compostas enquanto sua união à estrutura dental não apresentar suficiente resistência ou não se evitar a contração da resina composta

Retention of oral microorganisms on conventional and resin-modified glass-ionomer cements Retenção de microrganismos bucais em cimentos de ionômero de vidro convencionais e modificados por resina

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Denise PEDRINI

2001-09-01

Full Text Available Secondary caries are a worldwide public and socioeconomic problem. The placement of restorations can lead to the development of environmental conditions favorable to microbial colonization, especially on the tooth/restoration interface, which is a predisposing factor for secondary caries. The aim of this study was to evaluate microbial retention on conventional (Chelon-Fil and Vidrion R and resin-modified (Vitremer and Fuji II LC glass-ionomer cements, in situ, using a hybrid composite resin (Z100 as a control. Twelve volunteers wore Hawley appliances with specimens made of all tested filling materials for 7 days. The specimens were then removed from the appliances and transferred to tubes containing 2.0 ml of Ringer-PRAS. Microorganisms from the samples were inoculated onto blood agar and Mitis Salivarius Bacitracin agar and incubated under anaerobiosis (90% N2, 10% CO2, at 37°C, for 10 and 2 days, respectively. The resin-modified glass-ionomer cements and the composite resin retained the same levels of microorganisms on their surfaces. The resin-modified glass-ionomers retained less mutans streptococci than the composite resin and conventional glass-ionomer cements. The conventional glass-ionomer cements retained less mutans streptococci than the composite resin, but that difference was not statistically significant.A cárie secundária representa problema de saúde pública e socioeconômico no mundo. A restauração de dentes acometidos por cárie pode criar condições favoráveis à proliferação microbiana na superfície do material restaurador ou na interface dente/restauração, criando ambiente propício para o estabelecimento de cárie secundária. O objetivo deste estudo foi avaliar a capacidade de retenção de placa bacteriana em cimentos de ionômero de vidro convencionais (Chelon-Fil e Vidrion R e modificados por resina (Vitremer e Fuji II LC e de resina composta híbrida (Z100, utilizada como controle. Nos testes de reten

Tableros de partículas de bambú (Bambusa vulgaris Schrad y resina poliuretana a base de aceite de rícino (Ricinus communis L.

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Flávio Januário José

Full Text Available Esta investigación tiene como objetivo la elaboración y la evaluación de tableros de partículas homogéneas aglomeradas, utilizándose dos materiales alternativos en la búsqueda de la sustentabilidad del proceso productivo. Fueron utilizadas partículas de Bambusa vulgaris Schrad por la rapidez del ciclo de producción de esta especie de bambú. Como pegante fue utilizada la resina poliuretana a base de aceite de ricino (Ricinus communis L., por su origen parcialmente renovable, y por ser considerada no tóxica. Para la caracterización del material, fueron fabricadas, en escala de laboratorio, tableros de partículas de bambú con dimensiones inferiores al 2.4 mm, combinadas con 5%, 10% y 15% de resina en relación a la masa de partículas de bambú. Probetas fueron evaluadas de acuerdo con las especificaciones de la norma NBR 14810 - Tableros de madera aglomerada. Antes de los ensayos de compresión las probetas fueron evaluadas por medio del ensayo no destructivo por ultra-sonido. Los resultados obtenidos indicaron que los tableros con el contenido de 10% de resina no fue estadísticamente diferente al contenido de 15%, siendo ambos superiores al contenido de 5%. La mayoría de las propiedades de los tableros fueron inferiores a aquellas de los tableros comerciales. No fue posible correlacionar la velocidad del pulso de ultra-sonido con la resistencia a la compresión longitudinal.

Bioactivity-Guided Fractionation of the Traditional Chinese Medicine Resina Draconis Reveals Loureirin B as a PAI-1 Inhibitor

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Yu Jiang

2017-01-01

Full Text Available Thrombotic diseases have become a global burden due to morbidity, mortality, and disability. Traditional Chinese medicine has been proven effective in removing blood stasis and promoting blood circulation, but the exact mechanisms remain unclear. Plasminogen activator inhibitor-1 (PAI-1 is a natural inhibitor of tissue-type and urokinase-type plasminogen activators. In this study, we screened four fractions of Resina Draconis (a traditional Chinese medicine extract for PAI-1 inhibitory activity. Bioactivity-guided purification and chromogenic substrate-based assay led to the identification of loureirin B as the major PAI-1 inhibitor, with an IC50 value of 26.10 μM. SDS-PAGE analysis showed that formation of the PAI-1/uPA complex was inhibited by loureirin B, and the inhibitory effect of loureirin B on PAI-1 was also confirmed by clot lysis assay. In vivo studies showed that loureirin B significantly prolonged the tail bleeding time and reduced the weight and size of arterial thrombus, reduced hydroxyproline level, and partly cured liver fibrosis in mice. Taken together, the results revealed loureirin B as a PAI-1 inhibitor, adding a new pharmacological target for loureirin B and uncovering a novel mechanism underlying the antithrombotic property of Resina Draconis, which might be useful in the treatment of cardiovascular diseases such as thrombosis and fibrosis.

Influência da ciclagem térmica na resistência à flexão de resinas laboratoriais = The effect of thermo-cycling on flexural strength of laboratorial resins

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Oliveira, Karla Mychellyne Costa

2007-01-01

Full Text Available Introdução: Uma nova geração de resinas laboratoriais contendo micro-partículas cerâmicas em sua composição tem sido introduzida no mercado com a finalidade de melhorar suas propriedades mecânicas. Objetivo: O objetivo deste estudo foi avaliar o efeito da termociclagem na resistência à flexão de três resinas laboratoriais. Materiais e método: Foram confeccionadas 48 barras com medidas de 2 mm × 2 mm × 25 mm, utilizando as resinas laboratoriais: G1 - RESILAB MASTER (Wilcos, Brasil, G2 - VITA VM LC (Vita Zanhfabrik, Germany, G3 - VITA ZETA LC (Vita Zanhfabrik, Germany. A metade das barras de cada grupo foi submetida a 3000 ciclos térmicos (5ºC/55ºC ± 1, com banhos de 30 s. Os ensaios mecânicos foram efetuados em máquina de ensaio universal EMIC com capacidade de carga de 100 kg e velocidade de 0,5 mm/min. Resultados: Os dados obtidos foram analisados estatisticamente pelo teste de ANOVA (two-way e Tukey (p < 0,05. As médias (± DP observadas para os grupos sem ciclagem foram: G1(112,6 ± 25,39, G2(116,5 ± 18,51 e G3(136,1 ± 24,34; e para os grupos com ciclagem: G1(91,8 ± 18,86, G2(101,9 ± 20,61 e G3(89,9 ± 23,05. Conclusão: Concluiu-se que a diminuição da resistência à flexão em MPa está diretamente dependente da ciclagem térmica nos grupos testados, sendo que os maiores valores foram obtidos pela resina VITA VM LC. Entretanto, na condição sem ciclagem térmica a VITA ZETA apresentou os maiores valores

Resistência à tração entre amálgama e resina composta em diferentes condições de oxidação - estudo in vitro

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YOUSSEF Michel Nicolau

1999-01-01

Full Text Available Este trabalho estuda in vitro a resistência à tração de corpos-de-prova de amálgama-resina composta unidos pelo adesivo dental Scotchbond Multi-Uso Plus. Os corpos-de-prova foram divididos em três grupos de dez, sendo que cada corpo era o resultado da união de dois discos, um de amálgama e outro de resina composta. Esses discos foram obtidos dentro de cilindros de baquelite e sofreram acabamento superficial com lixa de grana 600. Pretendeu-se simular a técnica do amalcomp e verificar a resistência à tração entre o amálgama e a resina composta em diferentes condições de oxidação do amálgama. Dos resultados obtidos e mediante análise de variância e teste de Tukey a 5%, pôde-se concluir que: o Grupo 3, que ficou na saliva artificial por trinta dias e portanto sofreu maior oxidação, apresenta resistência à tração superior e estatisticamente significante em relação aos grupos 1 e 2; o Grupo 2, que ficou na saliva por sete dias e sofreu menor oxidação, não apresenta resistência à tração estatisticamente superior ao Grupo 1 de amálgama recém-condensado.

Obtención y caracterización de harinas compuestas de endospermo - germen de maíz y su uso en la preparación de arepas

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HERNÁNDEZ Blanca D.

1999-01-01

Full Text Available La arepa, pan de maíz, es un producto elaborado a partir de harina precocida de endospermo de maíz, de elevado consumo en Colombia y Venezuela. Al obtener la harina de endospermo queda como subproducto el germen del que se extrae aceite que deja como residuo el germen desgrasado (GD. En el presente trabajo se formularon harinas compuestas del endospermo - GD. Se hicieron mezclas sustituyendo la harina precocida en 6, 8, 10 y 12%. Se evaluaron las propiedades físico - químicas, funcionales, sensoriales y nutricionales. Se encontró que al agregar el germen no aumenta significativamente la cantidad de proteína pero si mejora en más de un 300% la calidad nutricional de la misma, en la cual la relación de eficiencia proteica pasa de 0,16 hasta 1,04 en las harinas compuestas. La digestibilidad en las mezclas (> 89,5%, fue superior al valor obtenido para la harina precocida (84,02%. El contenido en fibra y grasa no varió significativamente en la harina compuesta, así mismo el color, peso específico, pH, separación de agua, adhesividad, absorción y solubilidad en agua no mostraron variaciones significativas. Sustituciones mayores a 6% mostraron pequeñas desviaciones respecto al rango establecido (3-5 cm para la expansión, sin afectar el amasado. Se prepararon arepas evaluándose su aceptabilidad. Se encontró que las arepas con 6% de GD fueron de mayor preferencia al compararlas con arepas de harina precocida, por lo que se concluyó que este porcentaje de sustitución sería el más viable, para enriquecer la harina precocida.

Produção de chapas de partículas orientadas “OSB” de Eucalyptus grandis com diferentes teores de resina, parafina e composição em camadas.

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Setsuo Ivakiri

2010-08-01

Full Text Available Este trabalho foi desenvolvido com o objetivo de avaliar a influência dos seguintes parâmetros de processo de produção sobre as propriedades das chapas "OSB": composição das chapas em camadas cruzadas com proporções face-miolo-face de 30-40-30 e 20-60-20 em relação à composição homogênea; e, quantidades de 3, 4,5 e 6,0% de resina fenol-formaldeído, com incorporação de 0,5 e 1,0% de emulsão de parafina. Os resultados demonstraram que a composição das chapas, com a relação 20-60-20, apresentou melhor balanço das propriedades de flexão estática entre os sentidos de ensaios paralelo e perpendicular ao plano da chapa. A quantidade de 6,0% de resina foi a que resultou em melhores propriedades físico-mecânicas das chapas "OSB". A produção de chapas "OSB" de Eucalyptus grandis, com 4,5 e 6,0% de resina fenol-formaldeído, superou as exigências mínimas de propriedades mecânicas das chapas "OSB" referendadas pela norma canadense CSA 0437-0 (1993.

Alternativas técnicas para o controle das alterações dimensionais das resinas acrílicas em prótese total

OpenAIRE

GOMEZ Tomas; MORI Matsuyoshi; CORRÊA Gerson de Arruda; MATSON Edmir

1998-01-01

Os autores propõem uma nova técnica para diminuição dos problemas provenientes das alterações dimensionais das resinas acrílicas utilizadas na confecção das próteses totais. Com essa proposta, conseguiu-se praticamente eliminar essas alterações dimensionais tão prejudiciais às próteses totais.

Implante de um floculado de resina de mamona em alvéolo dental de rato

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CALIXTO Romeu Felipe Elias

2001-01-01

Full Text Available Os objetivos do presente trabalho foram: 1 testar a biocompatibilidade de uma resina natural, derivada do óleo de mamona, implantada na cavidade de extração dental de ratos, e 2 estudar a possível interferência do material na cronologia do reparo alveolar. O material (AUG-EX, Poliquil Araraquara Polímeros Químicos Ltda., Araraquara - SP foi implantado no alvéolo imediatamente após a extração do incisivo superior direito e os ratos foram sacrificados de 1 a 6 semanas após a extração ou extração + implante. As hemimaxilas foram descalcificadas e processadas para inclusão em parafina e obtenção de cortes semi-seriados, corados com hematoxilina-eosina. Os flocos da resina, de forma irregular e tamanho variável, localizaram-se entre os terços alveolares médio e cervical, inicialmente circundados por tecido de granulação e a seguir por quantidade progressivamente maior de tecido ósseo, no geral com a presença de um tecido conjuntivo interposto, mas em algumas áreas estabelecendo aparente osseointegração direta. Não houve persistência da reação inflamatória, mas observou-se pequena quantidade de células gigantes aderidas à superfície do material, em todos os períodos. A análise histométrica (contagem diferencial de pontos do terço apical mostrou um atraso de 13% a 20% no reparo alveolar dos ratos implantados, com menor neoformação óssea associada a maiores volumes percentuais de tecido conjuntivo e de remanescentes do coágulo sangüíneo.

Análise de peças anatômicas preservadas com resina de poliester para estudo em anatomia humana Analysis of anatomical pieces preservation with polyester resin for human anatomy study

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Ítalo Martins de Oliveira

2013-02-01

Full Text Available OBJETIVO: avaliar o uso da resina de poliéster na preservação de peças anatômicas para estudo da anatomia humana. MÉTODOS: foram utilizadas 150 peças anatômicas, sendo as mesmas não fixadas (frescas, fixadas em formol a 10% e moldes vasculares de órgãos injetados com acetato de vinil e a resina de poliéster. A solução utilizada foi composta de resina de poliéster com seu diluente monômero de estireno e catalisador (peroxol. Foram obtidos, após a inclusão nesta solução, modelos em resina transparente, que permitiam a plena observação das estruturas e conservação da peça utilizada. RESULTADOS: na avaliação das peças, foi observado grau de extrema transparência, promovendo uma completa visualização das estruturas com a perfeita preservação da anatomia. A duração média para a completa finalização da inclusão foi 48 horas. Apenas 14 peças (9,3% foram inutilizadas durante o preparo. CONCLUSÃO: a resina de poliéster pode ser utilizada para a preservação de peças anatômicas para o ensino da anatomia humana, de maneira prática, estética e duradoura.OBJECTIVE: To evaluate the use of polyester resin in preserving anatomical specimens for the study of human anatomy. METHODS: We used 150 anatomical specimens, comprised of unfixed (fresh, fixed in 10% formalin and vascular casts of organs injected with vinyl acetate and polyester resin. The solution used consisted of polyester resin with the diluent styrene monomer and catalyst (peroxol. After embedding in this solution, models in transparent resin were obtained, allowing full observation of structures and conservation of the specimens used. RESULTS: upon evaluation of the specimens, we observed a high degree of transparency, which promoted a complete visualization of structures with perfect preservation of the anatomy. The average time for the completion of the embedding was 48 hours. Only 14 specimens (9.3% were lost during the preparation. CONCLUSION

Infiltração marginal em restaurações de resina composta com diferentes materiais adesivos intermediários = Marginal leakage in resin composite restorations lined with different adhesive materials

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Moraes, Rafael Stanziona de

2007-01-01

Full Text Available Este estudo avaliou a capacidade de selamento de restaurações de resina composta com diferentes materiais adesivos intermediários. Cavidades Classe V padronizadas, com margens em esmalte e dentina/cemento, foram confeccionadas em incisivos bovinos. A resina de alto escoamento Fill Magic (Vigodent e o cimento ionomérico Vitremer (3M ESPE foram empregados como intermediários de restaurações com os compósitos Charisma e Solitaire (Heraeus Kulzer, formando 6 grupos (n = 14: [C1] – compósito microhíbrido Charisma; [C2] – Fill Magic + Charisma; [C3] – Vitremer + Charisma; [S1] – compósito condensável Solitaire; [S2] – Fill magic + Solitaire; [S3] – Vitremer + Solitaire. Após acabamento e polimento, as amostras foram armazenadas em solução fisiológica a 37ºC, por 30 dias, e então imersas em solução de fucsina básica a 0,5% por 24h. Os dentes foram longitudinalmente seccionados e a penetração do corante avaliada sob magnificância (40×, por dois examinadores, com escores padronizados. Os dados foram submetidos ao teste estatístico não-paramétrico de Kruskal-Wallis. Nas margens em esmalte, diferenças significativas foram verificadas apenas para a associação de intermediários à resina Solitaire, com os grupos S2 (p < 0,05 e S3 (p < 0,001 apresentando escores de infiltração significativamente maiores em relação aos demais. As margens em dentina/cemento apresentaram maior penetração em relação às margens em esmalte (p < 0,001. Apenas a associação do Vitremer às duas resinas melhorou o selamento deste substrato, com os grupos C3 (p < 0,001 e S3 (p < 0,05 apresentando os menores escores de infiltração

Estudo do comportamento fotofísico de prepregs de fibra de vidro e resina fenólica.

OpenAIRE

Rogério da Silva Rosa

2007-01-01

O objetivo desse trabalho é a aplicação da Espectroscopia de Luminescência em modo estacionário para o estudo do processo de cura de pré-impregnados (prepregs) de fibra de vidro e resina fenólica, tratadas termicamente em três diferentes temperaturas 90, 120 e 150 C. O processo de cura dos prepregs também foi monitorado por Espectroscopia de absorção na região do Infravermelho com transformada de Fourier (FT-IR). Os espectros de luminescência dos prepregs mostram mudanças significativas atrib...

Sal de iodônio aumenta a resistência coesiva de uma resina adesiva experimental na presença de solvente

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Fernanda B. Leal

2013-01-01

Full Text Available Este estudo avaliou o efeito da concentração de solvente na resistência coesiva de um adesivo experimental contendo um derivado do difeniliodônio. Uma blenda monomérica baseada em Bis-GMA, TEGDMA e HEMA foi utilizada como resina adesiva modelo. Foram avaliados dois sistemas de fotoiniciação: um sistema bináriocanforquinona (CQ e etil 4-dimetilamino benzoato (EDAB] e um sistema ternário [CQ, EDAB e hexafluorfosfato de difeniliodônio (DPI]. Nestas resinas foram adicionadas diferentes concentrações de etanol, 0, 5, 10, 20, 30, 40% e teste de resistência coesiva foi utilizado para investigar o efeito deste solvente sobre as propriedades do material. A presença de solvente reduziu a resistência coesiva do polímero, independentemente do sistema de fotoiniciação utilizado. Além disso, o uso do sal de iodônio no sistema de fotoiniciação aumentou a resistência coesiva quando comparado com o sistema binário, e independentemente da concentração de solvente, a resistência coesiva dos polímeros contendo difeniliodônio foi superior à do sistema binário de fotoiniciação.

CONDENSATION OF WATER VAPOR IN A VERTICAL TUBE CONDENSER

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Jan Havlík

2015-10-01

Full Text Available This paper presents an analysis of heat transfer in the process of condensation of water vapor in a vertical shell-and-tube condenser. We analyze the use of the Nusselt model for calculating the condensation heat transfer coefficient (HTC inside a vertical tube and the Kern, Bell-Delaware and Stream-flow analysis methods for calculating the shell-side HTC from tubes to cooling water. These methods are experimentally verified for a specific condenser of waste process vapor containing air. The operating conditions of the condenser may be different from the assumptions adopted in the basic Nusselt theory. Modifications to the Nusselt condensation model are theoretically analyzed.

Estabilidade dimensional de uma resina acrílica para coroas provisórias em função de diferentes técnicas de processamento ao longo do tempo

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David Alejandro García-López

Full Text Available INTRODUÇÃO: A estabilidade dimensional das resinas acrílicas influencia na adaptação das coroas provisórias e, consequentemente, no resultado do tratamento reabilitador. OBJETIVO: Avaliar a estabilidade dimensional, ao longo do tempo, de uma resina acrílica processada de diferentes maneiras. MATERIAL E MÉTODO: Cinco técnicas de polimerização da resina acrílica foram testadas: I - polimerização térmica utilizando líquido de polimerização rápida em mufla; II - autopolimerização sob pressão; III - autopolimerização utilizando pincel; IV - autopolimerização após mistura (pó + líquido em pote Dappen e inserção em matriz de aço na fase arenosa; V - autopolimerização após mistura em pote Dappen com inserção na matriz metálica na fase plástica. Foram confeccionados dez corpos de prova para cada tipo de processamento. Avaliou-se a estabilidade dimensional por meio de matriz de aço inox confeccionada segundo a especificação nº19 da ADA. Os corpos de prova foram armazenados em água destilada a 37ºC e examinados nos períodos de 1 hora, 1, 7, 15, 10, 90 e 180 dias após a polimerização, com o auxílio de um microscópio óptico com aumento de 20×. Os resultados foram submetidos à análise de dupla variância (Teste de Tukey para Tempo e Técnica de processamento em nível de 5% de significância. RESULTADO: Todos os grupos experimentais apresentaram alterações dimensionais entre o sétimo e o 15º dia; após esse período de tempo, houve alterações dimensionais estatisticamente significantes, para as diferentes técnicas estudadas. CONCLUSÃO: A estabilidade dimensional da resina acrílica não sofreu influência das diferentes técnicas de processamento avaliadas; entretanto, foi influenciada pelo tempo de armazenamento.

Steam condenser

International Nuclear Information System (INIS)

Masuda, Fujio

1980-01-01

Purpose: To enable safe steam condensation by providing steam condensation blades at the end of a pipe. Constitution: When high temperature high pressure steam flows into a vent pipe having an opening under water in a pool or an exhaust pipe or the like for a main steam eacape safety valve, non-condensable gas filled beforehand in the steam exhaust pipe is compressed, and discharged into the water in the pool. The non-condensable gas thus discharged from the steam exhaust pipe is introduced into the interior of the hollow steam condensing blades, is then suitably expanded, and thereafter exhausted from a number of exhaust holes into the water in the pool. In this manner, the non-condensable gas thus discharged is not directly introduced into the water in the pool, but is suitable expanded in the space of the steam condensing blades to suppress extreme over-compression and over-expansion of the gas so as to prevent unstable pressure vibration. (Yoshihara, H.)

Preventing freezing of condensate inside tubes of air cooled condenser

International Nuclear Information System (INIS)

Joo, Jeong A; Hwang, In Hwan; Lee, Dong Hwan; Cho, Young Il

2012-01-01

An air cooled condenser is a device that is used for converting steam into condensate by using ambient air. The air cooled condenser is prone to suffer from a serious explosion when the condensate inside the tubes of a heat exchanger is frozen; in particular, tubes can break during winter. This is primarily due to the structural problem of the tube outlet of an existing conventional air cooled condenser system, which causes the backflow of residual steam and noncondensable gases. To solve the backflow problem in such condensers, such a system was simulated and a new system was designed and evaluated in this study. The experimental results using the simulated condenser showed the occurrence of freezing because of the backflow inside the tube. On the other hand, no backflow and freezing occurred in the advanced new condenser, and efficient heat exchange occurred

Condensate subcooling near tube exit during horizontal in-tube condensation

International Nuclear Information System (INIS)

Hashizume, K.; Abe, N.; Ozeki, T.

1992-01-01

In-tube condensation is encountered in various applications for heat exchangers, such as domestic air-conditioning equipment, industrial air-cooled condensers, and moisture separator reheaters (MSRs) for nuclear power pants. Numerous research work has been conducted to predict the condensation heat transfer coefficient, and we have now enough information for thermal design of heat exchangers with horizontal in-tube condensation. Most of the research is analytical and/or experimental work in the annular or stratified flow regime, or experimental work on bulk condensation, i.e., from saturated vapor to complete condensation. On the other hand, there exist few data about the heat transfer phenomena in the very lower-quality region near the tube exit. The purpose of this paper is to clarify the condensation heat transfer phenomena near the tube exit experimentally and analytically, and to predict the degree of condensate subcooling

Influence of different kinds of rosins and hydrogenated resins on the setting time of Grossman cements Influência de diferentes tipos de breus e resinas hidrogenadas sobre o tempo de endurecimento dos cimentos do tipo Grossman

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Manoel Damião SOUSA NETO

1999-01-01

Full Text Available In this study, the effect on the setting time by the addition of different kinds of rosin and hydrogenated resin on the Grossman cement powder was evaluated. The experiments were carried out following the American Dental Association’s specification number 57 for root canal sealers. For this analysis, different Grossman cement powders were prepared using different rosins (X, WW and WG and hydrogenated resins (Staybelite and Staybelite ester 10. The study of the physicochemical properties of the Grossman cements obtained the different kinds of rosins and hydrogenated resins interference on the cement’s setting time. The hydrogenated resin, having a higher pH, increased the setting time of the cement when compared to the X, WW and WG rosins.No presente estudo, analisou-se o efeito da adição de diferentes tipos de breus e resinas hidrogenadas ao pó do cimento de GROSSMAN sobre o tempo de endurecimento. Os experimentos foram realizados de acordo com a Especificação 57 para materiais obturadores de canais radiculares da American Dental Association (ADA. Para análise, foram aviados pós do cimento de GROSSMAN com diferentes tipos de breu (X, WW e WG e resinas hidrogenadas (Stabylite e Stabylite éster 10. Os estudos das propriedades físico-químicas dos cimentos tipo GROSSMAN obtidos de diferentes tipos de breus e resinas hidrogenadas interferem no tempo de endurecimento do cimento. A resina hidrogenada, obtida do processo de hidrogenação tem o pH mais alto, provocando um aumento do tempo de endurecimento do cimento em relação aos breus tipo X, WW e WG, que têm pH mais ácido.

Comparação dos valores de desgaste abrasivo e de microdureza de 13 resinas compostas usadas em odontologia através do método do disco retificado Comparing abrasive wear and microhardness of 13 dental composite resins

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Eduardo C. Bianchi

2007-06-01

Full Text Available Atualmente tem-se buscado simplificar a tarefa de caracterização da vida útil de restaurações dentárias realizadas por resinas compostas através de métodos laboratoriais, que são mais rápidos e não sofrem influência de variáveis pessoais inerentes às análises clínicas. Com este propósito, este trabalho apresenta uma nova metodologia de ensaio laboratorial para a avaliação do desgaste abrasivo de resinas compostas através do método do disco retificado. Realizaram-se ensaios de resistência ao desgaste abrasivo com 13 resinas compostas odontológicas e buscou-se analisar o comportamento da resistência ao desgaste abrasivo em relação à microdureza dessas resinas. Com a análise dos resultados concluiu-se que o método de discos retificados é eficiente para a obtenção da resistência ao desgaste abrasivo. Notou-se também ser extremamente pequeno o nível de correlação entre microdureza e desgaste abrasivo o que indica que cada resina composta tem características próprias e que o desgaste é dependente também de outros fatores.It is now commonplace to search for methods to assess the useful lifetime of dental restorations made of resins, which are quicker and less subjective than clinical analyses. With this purpose, this work presents a new methodology based on the grinding disk for evaluating the abrasive wear of composed resins. Resistance tests to the abrasive wear were made with 13 composed resins used as dental material, and a comparison was done with the hardness of those resins. From the data analysis, we concluded that the method of rectified disks is efficient for obtaining the resistance to the abrasive wear. Furthermore, the correlation between hardness and abrasive wear was very small, which indicates that each composed resin has its own characteristics and that the wear also depends on other factors.

Water Condensation

DEFF Research Database (Denmark)

Jensen, Kasper Risgaard; Fojan, Peter; Jensen, Rasmus Lund

2014-01-01

The condensation of water is a phenomenon occurring in multiple situations in everyday life, e.g., when fog is formed or when dew forms on the grass or on windows. This means that this phenomenon plays an important role within the different fields of science including meteorology, building physics......, and chemistry. In this review we address condensation models and simulations with the main focus on heterogeneous condensation of water. The condensation process is, at first, described from a thermodynamic viewpoint where the nucleation step is described by the classical nucleation theory. Further, we address...

Regeneración de una resina de cambio iónico para su uso en la disminución de la dureza del agua. Simulación animada del proceso.

OpenAIRE

Milla González, Miguel

2015-01-01

Mediante una sencilla animación se muestra la sustitución de los iones metálicos (calcio) por protones en la regeneración con HCl de una resina catiónica para su uso posterior en el ablandamiento de una muestra de agua.

Dureza knoop de resinas compostas em função do número relativo de radicais livres Relative number of free radicals and knoop hardness of composites

Directory of Open Access Journals (Sweden)

Marco Aurélio de MENEZES

1998-07-01

Full Text Available A pesquisa teve a finalidade de determinar o número relativo de radicais livres e a dureza Knoop de três resinas compostas (Z100, Silux Plus e Heliomolar RO. Para o ensaio dos radicais livres, as irradiações foram: 110, 180, 300, 580 mW/cm2, pelos tempos de 10, 20, 30, 40, 50, 60, 80 e 90 segundos. As durezas foram determinadas com as cores claras com irradiação de 110 e 300 mW/cm2, por 20, 40, 60 e 80 segundos, nas faces da frente e do fundo, nas idades de 5 minutos, 1 hora, 1 dia, 1 semana e 1 mês. As conclusões foram: a resina Z100 apresentou cerca de 3 vezes mais radicais livres do que as outras; o número relativo de radicais livres aumenta com a intensidade e tempo de exposição; maior intensidade de luz aumentou a dureza; maior tempo de exposição aumentou as durezas das resinas Silux Plus e Heliomolar, mas não da Z100; a dureza aumentou com a idade até 1 mês; o lado da irradiação apresentou maior dureza do que o do fundo; a resina Z100 foi bem mais dura e sofreu menos a influência da irradiação.The present study had the purpose of determining the relative number of free radicals of three composites with clear and dark colors. Intensities of irradiation were: 110, 180, 300, and 580 mW/cm2, for 10, 20, 30, 40, 50, 60, 80 and 90 seconds. Hardness was determined for the clear colors of the composites, using 110 and 300 mW/cm2 irradiation intensities, for 20, 40, 60, and 80 seconds, on front and deep surfaces, at the ages of 5 minutes, 1 hour, 1 day, 1 week, and 1 month. The conclusions were that: depending on the resin, clear colors present more free radicals; the number of free radicals increases with higher intensity and longer irradiation time; composite Z100 is much richer in free radicals than Silux Plus and Heliomolar RO; higher intensity of irradiation leads to increasing hardness; longer irradiation time increases hardness of Silux Plus and Heliomolar RO, but not that of Z100; hardness increases with age; in depth

Evaluation of the surface hardness of composite resins before and after polishing at different times Avaliação da dureza superficial de resinas compostas antes e após o polimento em diferentes tempos

Directory of Open Access Journals (Sweden)

Michelle Alexandra Chinelatti

2006-06-01

Full Text Available PURPOSE: The aim of this study was to evaluate the surface hardness of six composite resins: Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (microfilled and Z100 (minifilled before and after polishing at different times. MATERIALS AND METHODS: For this purpose, 240 specimens (5mm diameter, 1.4mm high were prepared. Vickers hardness was determined before and after polishing at different times: immediately, 24h, 7 and 21 days after preparation of the samples. Statistical analysis was performed by ANOVA and Tukey test. RESULTS: There was no difference in the hardness of flowable resins, which had lower hardness than the minifilled resin. The minifilled resin showed the highest surface hardness as compared to the other materials (pPROPOSIÇÃO: O objetivo deste estudo foi avaliar a dureza superficial de seis resinas compostas - Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (micropartículas e Z100 (híbrida - antes e após o polimento realizado em diferentes tempos. MATERIAL E MÉTODO: Foram confeccionados 240 corpos-de-prova circulares (5mm de diâmetro e 1,4mm de altura. A dureza Vickers foi obtida antes e após o polimento realizado em diferentes tempos: imediatamente, 24 horas, 7 dias e 21 dias após a confecção do corpo-de-prova. Os dados foram analisados estatisticamente por meio da ANOVA e do Teste de Tukey. RESULTADOS: Não houve diferença entre as resinas compostas flowable, as quais apresentaram os menores valores de dureza. A resina composta híbrida demonstrou os melhores resultados. Todos os materiais exibiram aumento de dureza após a realização do polimento, que foi mais evidente após 7 dias. CONCLUSÃO: Pôde-se concluir que, independente do tipo de resina composta, a dureza superficial foi consideravelmente maior quando o polimento foi realizado 1 semana após a confecção dos corpos-de-prova.

Endogenous or exogenous spreading of HIV-1 in Nordrhein-Westfalen, Germany, investigated by phylodynamic analysis of the RESINA Study cohort.

Science.gov (United States)

Lawyer, Glenn; Schülter, Eugen; Kaiser, Rolf; Reuter, Stefan; Oette, Mark; Lengauer, Thomas

2012-08-01

HIV's genetic instability means that sequence similarity can illuminate the underlying transmission network. Previous application of such methods to samples from the United Kingdom has suggested that as many as 86% of UK infections arose outside of the country, a conclusion contrary to usual patterns of disease spread. We investigated transmission networks in the Resina cohort, a 2,747 member sample from Nordrhein-Westfalen, Germany, sequenced at therapy start. Transmission networks were determined by thresholding the pairwise genetic distance in the pol gene at 96.8% identity. At first blush the results concurred with the UK studies. Closer examination revealed four large and growing transmission networks that encompassed all major transmission groups. One of these formed a supercluster containing 71% of the sex with men (MSM) subjects when the network was thresholded at levels roughly equivalent to those used in the UK studies, though methodological differences suggest that this threshold may be too generous in the current data. Examination of the endo- versus exogenesis hypothesis by testing whether infections that were exogenous to Cologne or to Dusseldorf were endogenous to the greater region supported endogenous spread in MSM subjects and exogenous spread in the endemic transmission group. In intravenous drug using group subjects, it depended on viral strain, with subtype B sequences appearing to have origin exogenous to the Resina data, while non-B sequences (primarily subtype A) were almost completely endogenous to their local community. These results suggest that, at least in Germany, the question of endogenous versus exogenous linkages depends on subject group.

Utilização de uma resina preparada pelo método da solução líquida de citratos como ligante durante a preparação de filtros cerâmicos à base de alumina

OpenAIRE

Gouvêa,D.; Savaglia Neto,W. A.; Capocchi,J. D. T.

1999-01-01

Este trabalho propõe a preparação de filtros cerâmicos macroporosos pela técnica da impregnação de espumas de poliuretano e utilização de uma resina preparada pelo método Pechini contendo íons alumínio e manganês como ligante. Nas temperaturas inferiores à de combustão da resina a parte orgânica age com ligante. Após a decomposição térmica, o produto da combustão, ou seja, alumina contendo íons Mn, passa a ser um ligante inorgânico mas apresentando composição química semelhante à do filtro. O...

Performance of evaporative condensers

Energy Technology Data Exchange (ETDEWEB)

Ettouney, Hisham M.; El-Dessouky, Hisham T.; Bouhamra, Walid; Al-Azmi, Bader

2001-07-01

Experimental investigation is conducted to study the performance of evaporative condensers/coolers. The analysis includes development of correlations for the external heat transfer coefficient and the system efficiency. The evaporative condenser includes two finned-tube heat exchangers. The system is designed to allow for operation of a single condenser, two condensers in parallel, and two condensers in series. The analysis is performed as a function of the water-to-air mass flow rate ratio (L/G) and the steam temperature. Also, comparison is made between the performance of the evaporative condenser and same device as an air-cooled condenser. Analysis of the collected data shows that the system efficiency increases at lower L/G ratios and higher steam temperatures. The system efficiency for various configurations for the evaporative condenser varies between 97% and 99%. Lower efficiencies are obtained for the air-cooled condenser, with values between 88% and 92%. The highest efficiency is found for the two condensers in series, followed by two condensers in parallel and then the single condenser. The parallel condenser configuration can handle a larger amount of inlet steam and can provide the required system efficiency and degree of subcooling. The correlation for the system efficiency gives a simple tool for preliminary system design. The correlation developed for the external heat transfer coefficient is found to be consistent with the available literature data. (Author)

Condensation of steam

International Nuclear Information System (INIS)

Prisyazhniuk, V.A.

2002-01-01

An equation for nucleation kinetics in steam condensation has been derived, the equation taking into account the concurrent and independent functioning of two nucleation mechanisms: the homogeneous one and the heterogeneous one. The equation is a most general-purpose one and includes all the previously known condensation models as special cases. It is shown how the equation can be used in analyzing the process of steam condensation in the condenser of an industrial steam-turbine plant, and in working out new ways of raising the efficiency of the condenser, as well as of the steam-turbine plant as a whole. (orig.)

Modelling of condensation phenomena

International Nuclear Information System (INIS)

Jeong, Jae Jun; Chang, Won Pyo

1996-07-01

Condensation occurs when vapor is cooled sufficiently below the saturation temperature to induce the nucleation of droplets. Such nucleation may occur homogeneously within the vapor or heterogeneously on entrained particular matter. Heterogeneous nucleation may occur on the walls of the system, where the temperature is below the saturation temperature. There are two forms of heterogeneous condensation, drop-wise and film-wise. Another form of condensation occurs when vapor directly contacts to subcooled liquid. In nuclear power plant systems, all forms of condensation may occur during normal operation or accident conditions. In this work the modelling of condensation is surveyed, including the Nusselts' laminar film condensation theory in 1916, Rohsenow's turbulent film condensation model in 1950s, and Chen's models in 1987. Major attention is paid on the film condensation models among various research results because of its importance in engineering applications. It is found that theory, experiment, and empirical correlations for film condensation are well established, but research for drop-wise and direct-contact condensation are not sufficient yet. Condensation models in the best-estimate system codes such as RELAP5/MOD3 and CATHARE2 are also investigated. 3 tabs., 11 figs., 36 refs. (Author)

Improved condenser design and condenser-fan operation for air-cooled chillers

International Nuclear Information System (INIS)

Yu, F.W.; Chan, K.T.

2006-01-01

Air-cooled chillers traditionally operate under head pressure control via staging constant-speed condenser fans. This causes a significant drop in their coefficient of performance (COP) at part load or low outdoor temperatures. This paper describes how the COP of these chillers can be improved by a new condenser design, using evaporative pre-coolers and variable-speed fans. A thermodynamic model for an air-cooled screw-chiller was developed, within which the condenser component considers empirical equations showing the effectiveness of an evaporative pre-cooler in lowering the outdoor temperature in the heat-rejection process. The condenser component also contains an algorithm to determine the number and speed of the condenser fans staged at any given set point of condensing temperature. It is found that the chiller's COP can be maximized by adjusting the set point based on any given chiller load and wet-bulb temperature of the outdoor air. A 5.6-113.4% increase in chiller COP can be achieved from the new condenser design and condenser fan operation. This provides important insights into how to develop more energy-efficient air-cooled chillers

Proceedings: Condenser technology conference

International Nuclear Information System (INIS)

Tsou, J.L.; Mussalli, Y.G.

1991-08-01

Seam surface condenser and associated systems performance strongly affects availability and heat rate in nuclear and fossil power plants. Thirty-six papers presented at a 1990 conference discuss research results, industry experience, and case histories of condenser problems and solutions. This report contains papers on life extension, performance improvement, corrosion and failure analysis, fouling prevention, and recommendation for future R ampersand D. The information represents recent work on condenser problems and solutions to improve the procurement, operation, and maintenance functions of power plant personnel. Several key points follow: A nuclear and a fossil power plant report show that replacing titanium tube bundles improves condenser availability and performance. One paper reports 10 years of experience with enhanced heat transfer tubes in utility condensers. The newly developed enhanced condenser tubes could further improve condensing heat transfer. A new resistance summation method improves the accuracy of condenser performance prediction, especially for stainless steel and titanium tubed condensers. Several papers describe improved condenser fouling monitoring techniques, including a review of zebra mussel issues

Tratamiento de protección para tuberías de hormigón pretensado a base de resinas sintéticas (epoxi y poliuretano

Directory of Open Access Journals (Sweden)

Soria Santamaría, Francisco

1977-12-01

Full Text Available Amongst the different systems of protection used against the corrosion phenomenon under stress, we find those which physically try to prevent the corrosive agent from reaching the prestressed steel. Such is the case of water-proofing by means of synthetic resin-base membranes. The article describes the different tests to which this type of membrane should be submitted, with regard to the type of concrete used. It is also necessary to take into consideration the peculiarities of each job. The object of the tests made was to show the ideal characteristics of epoxy and polyurethane synthetic resins, especially formulated for specific functions. Three kinds of solutions are established with the use of these resins in those cases of protection against «aggressive» liquids, coming from water pipe exteriors, subjected to high pressures, where prestressed concrete piping has been used to solve this problem. Details are given on a specific job carried out in which one of the mentioned solutions was used.Entre los distintos sistemas de protección contra el fenómeno de corrosión bajo tensión, se encuentran aquellos que tratan de impedir físicamente que el agente corrosivo llegue al acero pretensado. Este es el caso de las impermeabilizaciones mediante membranas a base de resinas sintéticas. En el artículo se describen distintos ensayos a que deben someterse este tipo de membranas en lo que respecta al hormigón soporte. Es preciso, además, adaptarse a las particularidades propias del tipo de obra a que van destinadas. El objetivo de los ensayos ha sido el mostrar la idoneidad de resinas sintéticas de epoxi y de poliuretano, específicamente formuladas para unas funciones concretas. Se establecen tres tipos de soluciones mediante el empleo de las citadas resinas, en el caso de protección, respecto a líquidos «agresivos» provenientes del exterior en conducciones de agua, sometidas a altas presiones, en tuberías de hormig

Condensate cleaning systems

International Nuclear Information System (INIS)

Yamamoto, Michiyoshi; Oosumi, Katsumi; Takashima, Yoshie; Mitani, Shinji.

1982-01-01

Purpose: To decrease the frequency for the backwash and regeneration operations due to the increase in the differential pressure resulted from claddings captured in a mixed floor type desalter, and decrease the amount of radioactive liquid wastes of claddings from the condensate systems by removing claddings with electromagnetic filters. Constitution: In an existent plant, a valves is disposed between a condensate pump and a mixed floor type desalter. A pipeway is branched from a condensate pipe between the condensate pipe and the valve, through which condensates are transferred by a pump to an electromagnetic filter such as of a high gradient type electromagntic filter to remove claddings, then returned to a condensate pipe between the valve and the mixed floor type desalter and, thereafter, are removed with ionic components in the mixed floor type desalter and fed to the reactor. (Yoshino, Y.)

Condensation coefficient of water in a weak condensation state

International Nuclear Information System (INIS)

Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo

2008-01-01

The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].

Condensation coefficient of water in a weak condensation state

Science.gov (United States)

Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo

2008-07-01

The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].

Exposure to creosote bush phenolic resin causes avoidance in the leaf-cutting ant Acromyrmex lobicornis (Formicidae: Attini La exposición a la resina fenólica de jarilla causa deterrencia en la hormiga cortadora de hojas Acromyrmex lobicornis (Formicidae: Attini

Directory of Open Access Journals (Sweden)

ANA I MEDINA

2012-06-01

Full Text Available We focused our study on the effects of Larrea cuneifolia phenolic resin on leaf-cutting ants from two populations (Sierra de las Quijadas National Park and San Roque of Acromyrmex lobicornis in San Luis, Argentina. We conducted two bioassays of food choice (field and laboratory to compare the effects of phenolic resin on ant workers from these two populations. Results of the field experiment indicated that there were no differences in preference for either leaves treated with resin or untreated leaves among colonies from both localities. However, results of the laboratory experiments with individual ants indicated a significant effect of population and treatment on the time spent in different treatments. While leaf-cutting individual workers from Quijadas preferred the phenolic resin, workers from San Roque avoided it. These results evidence that ants respond according to time of exposure to chemicals from plants (presence or absence and that the effects of resin among a population can be observed and measured on individual ant workers, even in the absence of fungus garden influences in the nest.Este estudio se ha centrado en los efectos que produce la resina fenólica de Larrea cuneifolia sobre dos poblaciones distintas (Parque Nacional de Sierra de las Quijadas y la localidad de San Roque de Acromyrmex lobicornis en San Luis, Argentina. Se disenaron dos tipos de bioensayos (a campo y en laboratorio para comparar los efectos de la resina fenólica sobre las hormigas obreras de estas dos poblaciones. Los resultados de los experimentos de elección de la oferta alimentaria en el campo, indicaron que no hubo ninguna diferencia de preferencia entre las colonias, ni por las hojas tratadas con resina ni por las hojas sin tratar para ambas localidades. Sin embargo, los resultados de los experimentos de laboratorio con las hormigas obreras individualmente indicaron efectos significativos entre las poblaciones y entre los tratamientos. Mientras que las

Maintaining steam/condensate lines

International Nuclear Information System (INIS)

Russum, S.A.

1992-01-01

Steam and condensate systems must be maintained with the same diligence as the boiler itself. Unfortunately, they often are not. The water treatment program, critical to keeping the boiler at peak efficiency and optimizing operating life, should not stop with the boiler. The program must encompass the steam and condensate system as well. A properly maintained condensate system maximizes condensate recovery, which is a cost-free energy source. The fuel needed to turn the boiler feedwater into steam has already been provided. Returning the condensate allows a significant portion of that fuel cost to be recouped. Condensate has a high heat content. Condensate is a readily available, economical feedwater source. Properly treated, it is very pure. Condensate improves feedwater quality and reduces makeup water demand and pretreatment costs. Higher quality feedwater means more reliable boiler operation

Efecto del pH de los sitemas adhesivos autoacondicionantes sobre las características adhesivas de resinas compuestas.

OpenAIRE

Azócar Cabello, Teresa

2015-01-01

Objetivo: El presente estudio tiene como propósito analizar la ultraestructura microscópica de la dentina tratada con sistemas adhesivos autoacondicionantes de distinto pH. Métodos: 8 terceros molares humanos sanos fueron cortados horizontalmente para exponer dentina superficial y fueron distribuidos al azar en 4 grupos (n=2): Adper Single Bond 2 (SB), 3M ESPE, Go!, SDI (Go), pH leve, Adper Prompt L Pop, 3M ESPE (PLP), moderado, Xeno III, Dentsply (XE), fuerte. Se talló una cavidad clase I co...

Enhanced Condensation Heat Transfer

Science.gov (United States)

Rose, John Winston

The paper gives some personal observations on various aspects of enhanced condensation heat transfer. The topics discussed are external condensation (horizontal low-finned tubes and wire-wrapped tubes), internal condensation (microfin tubes and microchannels) and Marangoni condensation of binary mixtures.

Avaliação da interação entre resina composta e diferentes adesivos dentinários Evaluation of the interaction between composite resin and different dentin adhesives

Directory of Open Access Journals (Sweden)

Luciana Lourenço RIBEIRO

1999-01-01

Full Text Available O objetivo deste estudo foi avaliar a resistência à tração de quatro diferentes sistemas adesivos. Scotchbond Multi Purpose Plus, 3M (Grupo 1, Prime & Bond 2.0, Dentsply (Grupo 2 ProBOND, Dentsply (Grupo 3, PAAMA 2, (Grupo 4 foram usados com a resina composta Glacier (SDI. Um grupo sem a utilização de qualquer sistema adesivo serviu como controle (Grupo 5. Cinqüenta espécimes foram divididos em cinco grupos com dez espécimes cada. Uma matriz de aço inoxidável com 6,0 mm de diâmetro e 1,0 mm de profundidade foi usada para se obterem dois discos de resina composta. A resina composta foi inserida em uma metade da matriz em pequenas porções e fotopolimerizada por 40 segundos. Os adesivos foram então aplicados na superfície dos discos de resina, seguindo a instrução dos fabricantes. A segunda parte da matriz foi colocada em posição e preenchida com a resina composta. Após uma hora, a matriz foi adaptada em um dispositivo especial na máquina de ensaios Kratos para determinar a resistência de união, a uma velocidade de 0,05 mm/min. Os resultados, expressos em kgf, foram: Grupo 1 (3,99 ± 1,47, Grupo 2 (4,24 ± 2,00, Grupo 3 (3,84 ± 0,88, Grupo 4 (4,33 ± 1,23 e Grupo 5 (4,21 ± 1,38. Os resultados foram analisados pelo teste estatístico ANOVA a um critério. Não houve diferença estatisticamente significante (p The purpose of this study was to evaluate the tensile bond strength of four different adhesive systems. Scotchbond Multi-Purpose Plus, 3M (Group 1, Prime & Bond 2.0, Dentsply (Group 2, ProBOND, Dentsply (Group 3, PAAMA 2, SDI (Group 4 were used with GLACIER (SDI composite resin. One group without any adhesive was used as control (Group 5. Fifty specimens were divided into 5 groups of 10 each. A stainless steel split matrix with 6.00 mm diameter and 1.00 mm depth was used to obtain two discs of composite resin. The composite resin was applied into one half of the matrix in small portions and light cured for 40 seconds

The removal of toxic metals from liquid effluents by ion exchange resins. Part IV: Chromium(III)/H+ /Lewatit SP112; La eliminación de metales tóxicos presentes en efluentes líquidos mediante resinas de cambio iónico. Parte IV: cromo(III)/H+/Lewatit SP112

Energy Technology Data Exchange (ETDEWEB)

Alguacil, F.J.

2017-09-01

This investigation presented results on the removal of chromium(III), from aqueous solution in the 0-5 pH range, using Lewatit SP112 cationic exchange resin. Several aspects affecting the ion exchange process were evaluated, including: the influence of the stirring speed, temperature, pH of the solution, resin dosage and aqueous ionic strength. The selectivity of the system was tested against the presence of other metals in the aqueous solution, whereas the removal of chromium(III) from solutions was compared with results obtained using multiwalled carbon nanotubes as adsorbents. From the batch experimental data, best fit of the results is obtained with the Langmuir model, whereas the ion exchange process is best explained by the pseudo-second order model, moreover, experimental data responded well to the film-diffusion controlled model. Elution of the chromium(III) loaded into the resin is well accomplished by the use of sodium hydroxide solutions. [Spanish] En este trabajo se presentan los resultados obtenidos en la eliminación de cromo(III) de disoluciones acuosas (pH 0-5) mediante la resina de intercambio catiónico Lewatit SP112. Se han investigado algunas variables que pueden afectar al sistema: influencia de la agitación, temperatura, pH y fuerza iónica del medio acuoso y cantidad de resina; también se ha investigado acerca de la selectividad del sistema cuando otros metales están presentes en el medio acuoso, comparándose los resultados de la eliminación del cromo(III) usando la resina con los resultados obtenidos cuando se emplea otro adsorbente como son los nanotubos de carbono de pared múltiple. Los resultados experimentales indican que la carga del cromo(III) en la resina responde mejor al modelo de Langmuir, mientras que los modelos cinéticos indican que la carga del metal en la resina responde al modelo de pseudo-segundo orden y difusión en la capa límite. La elución del cromo(III) se realiza con disoluciones de hidróxid.

Comportamiento de vigas de sección compuesta con perfiles de acero laminado y losa de concreto empleando conectores de cortante tipo tornillo grado dos (2)

OpenAIRE

García Zamora, Alejandro; Molina Herrera, Maritzabel

2008-01-01

En el presente artículo, partiendo de un análisis teórico-experimental, se determinan y caracterizan los parámetros de diseño que rigen el comportamiento de las vigas compuestas de perfiles de acero y losa de concreto empleando conectores de cortante tipo tornillo, dado que para esta clase de conector no existe un estudio específico de su comportamiento, además en la actualidad su diseño no está definido en las NSR-98, aunque es uno de los tipos de conectores más empleados en la construcción ...

Comportamiento de vigas de sección compuesta con perfiles de acero laminado y losa de concreto empleando conectores de cortante tipo tornillo grado dos (2)

OpenAIRE

García Zamora, Alejandro; Molina Herrera, Maritzabel

2010-01-01

En el presente artículo, partiendo de un análisis teórico-experimental, se determinan y caracterizan los parámetros de diseño que rigen el comportamiento de las vigas compuestas de perfiles de acero y losa de concreto empleando conectores de cortante tipo tornillo, dado que para esta clase de conector no existe un estudio específico de su comportamiento, además en la actualidad su diseño no está definido en las NSR-98, aunque es uno de los tipos de conectores más empleados en la construcción ...

Measurement of liquid-liquid equilibria for condensate + glycol and condensate + glycol + water systems

DEFF Research Database (Denmark)

Riaz, Muhammad; Kontogeorgis, Georgios; Stenby, Erling Halfdan

2011-01-01

,2-ethanediol (MEG) + condensate and MEG + water + condensate systems at temperatures from (275 to 323) K at atmospheric pressure. The condensate used in this work is a stabilized natural gas condensate from an offshore field in the North Sea. Compositional analysis of the natural gas condensate was carried out...... by gas chromatography, and detailed separation of individual condensate's components has been carried out. Approximately 85 peaks eluting before nonane were identified by their retention time. Peak areas were converted to mass fraction using 1-heptene as an internal standard. The components were divided...... into boiling range groups from hexane to nonane. Paraffinic (P), naphthenic (N), and aromatic (A) distributions were obtained for the boiling point fractions up to nonane. The average molar mass and the overall density of the condensate were measured experimentally. For the mutual solubility of MEG...

Low pressure lithium condensation

International Nuclear Information System (INIS)

Wadkins, R.P.; Oh, C.H.

1985-01-01

A low pressure experiment to evaluate the laminar film condensation coefficients of lithium was conducted. Some thirty-six different heat transfer tests were made at system pressures ranging from 1.3 to 26 Pa. Boiled lithium was condensed on the inside of a 7.6-cm (ID), 409 stainless-steel pipe. Condensed lithium was allowed to reflux back to the pool boiling region below the condensing section. Fourteen chromel/alumel thermocouples were attached in various regions of the condensing section. The thermocouples were initially calibrated with errors of less than one degree Celsius

SLAC synchronous condenser

International Nuclear Information System (INIS)

Corvin, C.

1995-06-01

A synchronous condenser is a synchronous machine that generates reactive power that leads real power by 90 degrees in phase. The leading reactive power generated by the condenser offsets or cancels the normal lagging reactive power consumed by inductive and nonlinear loads at the accelerator complex. The quality of SLAC's utility power is improved with the addition of the condenser. The inertia of the condenser's 35,000 pound rotor damps and smoothes voltage excursions on two 12 kilovolt master substation buses, improving voltage regulation site wide. The condenser absorbs high frequency transients and noise in effect ''scrubbing'' the electric system power at its primary distribution source. In addition, the condenser produces a substantial savings in power costs. Federal and investor owned utilities that supply electric power to SLAC levy a monthly penalty for lagging reactive power delivered to the site. For the 1993 fiscal year this totaled over $285,000 in added costs for the year. By generating leading reactive power on site, thereby reducing total lagging reactive power requirements, a substantial savings in electric utility bills is achieved. Actual savings of $150,000 or more a year are possible depending on experimental operations

Conditions for maximum isolation of stable condensate during separation in gas-condensate systems

Energy Technology Data Exchange (ETDEWEB)

Trivus, N.A.; Belkina, N.A.

1969-02-01

A thermodynamic analysis is made of the gas-liquid separation process in order to determine the relationship between conditions of maximum stable condensate separation and physico-chemical nature and composition of condensate. The analysis was made by considering the multicomponent gas-condensate fluid produced from Zyrya field as a ternary system, composed of methane, an intermediate component (propane and butane) and a heavy residue, C/sub 6+/. Composition of 5 ternary systems was calculated for a wide variation in separator conditions. At each separator pressure there is maximum condensate production at a certain temperature. This occurs because solubility of condensate components changes with temperature. Results of all calculations are shown graphically. The graphs show conditions of maximum stable condensate separation.

Effects of non-condensable gas on the condensation of steam

International Nuclear Information System (INIS)

Jackson, J.D.; An, P.; Reinert, A.; Ahmadinejad, M.

2000-01-01

The experimental work reported here was undertaken with the aim of extending the database currently available on the condensation of steam in the presence of non-condensable gases and thereby improving the empirical input to thermal-hydraulic codes which might be used for design and safety assessment of advanced water-cooled nuclear reactors. Heat was removed from flowing mixtures of steam and air in a test section by means of a water-cooled condensing plate. The test facility constructed for the study incorporates a degassing unit which supplies water to a boiler. This delivers steam steadily to a mixing chamber where it joins with a flow of preheated air. The mixture of steam and air is supplied to the bottom of a cylindrical test section in which it flows upwards over a double sided condensing plate which can be vertical, inclined or horizontal, The rate at which heat is removed by cooling water flowing through internal passages in the plate can de determined calorimetrically knowing the flow rate of the water and its temperature rise. After commissioning experiments had shown that reliable measurements of condensation heat transfer rate could be made using the test facility, a programme of development work followed in the course of which three different designs of condensing plate were evaluated in turn. The version eventually used in the main programme of experiments which followed was made from copper. However, its surfaces were coated with a thin layer of nickel and then with one of chromium. It was found that such a surface consistently promoted dropwise condensation and showed no signs of deterioration after lengthy periods of use. The rate of heat removal from pure steam and from mixtures of steam and air in varying proportions was measured as a function of plate sub-cooling for a variety of plate orientations. (author)

Purification method for condensate

International Nuclear Information System (INIS)

Shimoda, Akiyoshi.

1996-01-01

Condensates generated in secondary coolant circuits of a PWR type reactor are filtered using a hollow thread separation membranes comprising aromatic polyether ketone. Preferably, condensates after passing through a turbine are filtered at a place between a condensator and a steam generator at high temperature as close as a temperature of the steam generator. As the hollow thread membrane, partially crystalline membrane comprising aromatic polyether ketone is used. When it is used at high temperature, the crystallinity is preferably not less than 15wt%. Since a hollow thread membrane comprising the aromatic polyether ketone of excellent heat resistance is used, it can filter and purify the condensates at not lower than 70degC. Accordingly, impurities such as colloidal iron can be removed from the condensates, and the precipitation of cruds in the condensates to a steam generator and a turbine can be suppressed. (I.N.)

Simple Simulations of DNA Condensation

Energy Technology Data Exchange (ETDEWEB)

STEVENS,MARK J.

2000-07-12

Molecular dynamics simulations of a simple, bead-spring model of semiflexible polyelectrolytes such as DNA are performed. All charges are explicitly treated. Starting from extended, noncondensed conformations, condensed structures form in the simulations with tetravalent or trivalent counterions. No condensates form or are stable for divalent counterions. The mechanism by which condensates form is described. Briefly, condensation occurs because electrostatic interactions dominate entropy, and the favored Coulombic structure is a charge ordered state. Condensation is a generic phenomena and occurs for a variety of polyelectrolyte parameters. Toroids and rods are the condensate structures. Toroids form preferentially when the molecular stiffness is sufficiently strong.

Condensation shocks in high momentum two-phase flows in condensing injectors

International Nuclear Information System (INIS)

Anand, G.; Christensen, R.N.

1993-01-01

This study presents a phenomenological and mathematical model of condensation shocks in high momentum two-phase flows in condensing injectors. The characteristics of the shock were related to the mode of vapor bubble collapse. Using cavitation terminology, the bubble collapse can be classified as inertially controlled or thermally controlled. Inertial bubble collapse occurs rapidly whereas, a thermally controlled collapse results in a significantly longer collapse time. The interdependence between the bubble collapse mode and the momentum and pressure of the flow, was analyzed in this study. For low-temperature-high-velocity flows a steep pressure rise with complete condensation was obtained. For a high-temperature-low velocity flow with noncondensables, low pressure recovery with incomplete condensation was observed. These trends are in agreement with previous experimental observations

Condensation in complex geometries

International Nuclear Information System (INIS)

Lauro, F.

1975-01-01

A mathematical evaluation of the condensation exchange coefficient can only succeds for well specified cases: small upright or inclined plates, horizontal tubes, small height vertical tubes. Among the main hypotheses accounted for this mathematical development in the case of the condensate, a laminar flow and uniform surface temperature are always considered. In practice certain shapes of surfaces significantly increase the heat transfer during the vapor condensation on a surface wet by the condensate. Such surfaces are rough surfaces such as the condensate is submitted to surface tension effects, negligeable for plane or large curvature surfaces, and the nature of the material may play an important role (temperature gradients). Results from tests on tubes with special shapes, performed in France or out of France, are given [fr

Sedimentary condensation and authigenesis

Science.gov (United States)

Föllmi, Karl

2016-04-01

Most marine authigenic minerals form in sediments, which are subjected to condensation. Condensation processes lead to the formation of well individualized, extremely thin ( 100ky), and which experienced authigenesis and the precipitation of glaucony, verdine, phosphate, iron and manganese oxyhydroxides, iron sulfide, carbonate and/or silica. They usually show complex internal stratigraphies, which result from an interplay of sediment accumulation, halts in sedimentation, sediment winnowing, erosion, reworking and bypass. They may include amalgamated faunas of different origin and age. Hardgrounds may be part of condensed beds and may embody strongly condensed beds by themselves. Sedimentary condensation is the result of a hydrodynamically active depositional regime, in which sediment accumulation, winnowing, erosion, reworking and bypass are processes, which alternate as a function of changes in the location and intensity of currents, and/or as the result of episodic high-energy events engendered by storms and gravity flow. Sedimentary condensation has been and still is a widespread phenomenon in past and present-day oceans. The present-day distribution of glaucony and verdine-rich sediments on shelves and upper slopes, phosphate-rich sediments and phosphorite on outer shelves and upper slopes, ferromanganese crusts on slopes, seamounts and submarine plateaus, and ferromanganese nodules on abyssal seafloors is a good indication of the importance of condensation processes today. In the past, we may add the occurrence of oolitic ironstone, carbonate hardgrounds, and eventually also silica layers in banded iron formations as indicators of the importance of condensation processes. Besides their economic value, condensed sediments are useful both as a carrier of geochemical proxies of paleoceanographic and paleoenvironmental change, as well as the product of episodes of paleoceanographic and paleoenvironmental change themselves.

Possibility of removing condensate and scattered oil from gas-condensate field during bed flooding

Energy Technology Data Exchange (ETDEWEB)

Belkina, N.A.; Yagubov, M.S.

1984-01-01

The problem is set of evaluating the possible removal from the bed of scattered oil and condensate during flooding of the bed. For this purpose, an experimental study was made of the displacement by water from the porous medium of the oil and condensate saturating it. The obtained experimental results permit evaluation of the possible removal from the gas-condensate bed of scattered oil and condensate during flooding of the bed.

Research progress of control of condensate depression for condenser

Science.gov (United States)

Liu, Ying; Liang, Run; Li, Fengyu

2017-08-01

It is introduced that significance and structure of the condensate depression control system. In accordance with controller devised procedure, we analyze and elaborate how to construct the lumped parameter and dynamic mathematical model which possesses distinct physics significance. Neural network model being called black-box model is also introduced. We analyze and contrast the control technique of condensate depression as conventional PI control, fuzzy PI control and fuzzy control. It is indicated that if the controller of condensate depression were devised inappropriate, while the steam discharged of turbine varying by a large margin, would result in the rotation rate of cooling water circulating pump accelerating at a great lick even to trigger the galloping danger which is less impressive for the units operating safely.

Biochemical analysis of the Hormoconis resinae fungal mycelium in the corrosion of aeronautical aluminium alloys

International Nuclear Information System (INIS)

Araya, R.; Bobadilla, C.; Vera, R.; Rosales, B. M.

2007-01-01

Biochemical analyses of the Hormoconis resinae fungal mycelium would explain behaviour differences of corrosive and non-corrosive strains of Al and its aeronautical alloys. In previous works its aggressiveness had been studied through SEM-EDX surface analysis, electrochemical techniques and immersion testing. In this paper separation of the proteins of the mycelium produced by a non-corrosive strain and its culture along three generations was performed. cultures were prepared in batch in the presence and absence of pure Al and AA 2024, AA 7005 and AA 7075 alloys. The mycelia grown throughout the three generations increasingly recovered usual characteristics at the third replication, included their corrosiveness on Al and its alloys previously shown by all out strains. Among the bio-molecule fractions isolated and analysed during this preliminary study only the proteins revealed changes with the generation grown. When this fungal strain was cultured in the presence of alloy metal sheets electrophoresis of the protean fraction was correlative with the distinct mycelia behaviour observed, including corrosiveness on Al and its alloys. (Author) 30 refs

Universal Themes of Bose-Einstein Condensation

Science.gov (United States)

Proukakis, Nick P.; Snoke, David W.; Littlewood, Peter B.

2017-04-01

Foreword; List of contributors; Preface; Part I. Introduction: 1. Universality and Bose-Einstein condensation: perspectives on recent work D. W. Snoke, N. P. Proukakis, T. Giamarchi and P. B. Littlewood; 2. A history of Bose-Einstein condensation of atomic hydrogen T. Greytak and D. Kleppner; 3. Twenty years of atomic quantum gases: 1995-2015 W. Ketterle; 4. Introduction to polariton condensation P. B. Littlewood and A. Edelman; Part II. General Topics: Editorial notes; 5. The question of spontaneous symmetry breaking in condensates D. W. Snoke and A. J. Daley; 6. Effects of interactions on Bose-Einstein condensation R. P. Smith; 7. Formation of Bose-Einstein condensates M. J. Davis, T. M. Wright, T. Gasenzer, S. A. Gardiner and N. P. Proukakis; 8. Quenches, relaxation and pre-thermalization in an isolated quantum system T. Langen and J. Schmiedmayer; 9. Ultracold gases with intrinsic scale invariance C. Chin; 10. Berezinskii-Kosterlitz-Thouless phase of a driven-dissipative condensate N. Y. Kim, W. H. Nitsche and Y. Yamamoto; 11. Superfluidity and phase correlations of driven dissipative condensates J. Keeling, L. M. Sieberer, E. Altman, L. Chen, S. Diehl and J. Toner; 12. BEC to BCS crossover from superconductors to polaritons A. Edelman and P. B. Littlewood; Part III. Condensates in Atomic Physics: Editorial notes; 13. Probing and controlling strongly correlated quantum many-body systems using ultracold quantum gases I. Bloch; 14. Preparing and probing chern bands with cold atoms N. Goldman, N. R. Cooper and J. Dalibard; 15. Bose-Einstein condensates in artificial gauge fields L. J. LeBlanc and I. B. Spielman; 16. Second sound in ultracold atomic gases L. Pitaevskii and S. Stringari; 17. Quantum turbulence in atomic Bose-Einstein condensates N. G. Parker, A. J. Allen, C. F. Barenghi and N. P. Proukakis; 18. Spinor-dipolar aspects of Bose-Einstein condensation M. Ueda; Part IV. Condensates in Condensed Matter Physics: Editorial notes; 19. Bose

Assessment of TRACE Condensation Model Against Reflux Condensation Tests with Noncondensable Gases

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyung Won; Cheong, Ae Ju; Shin, Andong; Suh, Nam Duk [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2015-05-15

The TRACE is the latest in a series of advanced, best-estimated reactor systems code developed by U.S. Nuclear Regulatory Commission for analyzing transient and steady-state neutronic-thermal-hydraulic behavior in light water reactors. This special model is expected to replace the default model in a future code release after sufficient testing has been completed. This study assesses the special condensation model of TRACE 5.0-patch4 against the counter-current flow configuration. For this purpose, the predicted results of special model are compared to the experimental and to those of default model. The KAST reflux condensation test with NC gases are used in this assessment. We assessed the special model for film condensation of TRACE 5.0-patch4 against the data of the reflux condensation test in the presence of NC gases. The special condensation model of TRACE provides a reasonable estimate of HTC with good agreement at the low inlet steam flow rate.

Assessment of TRACE Condensation Model Against Reflux Condensation Tests with Noncondensable Gases

International Nuclear Information System (INIS)

Lee, Kyung Won; Cheong, Ae Ju; Shin, Andong; Suh, Nam Duk

2015-01-01

The TRACE is the latest in a series of advanced, best-estimated reactor systems code developed by U.S. Nuclear Regulatory Commission for analyzing transient and steady-state neutronic-thermal-hydraulic behavior in light water reactors. This special model is expected to replace the default model in a future code release after sufficient testing has been completed. This study assesses the special condensation model of TRACE 5.0-patch4 against the counter-current flow configuration. For this purpose, the predicted results of special model are compared to the experimental and to those of default model. The KAST reflux condensation test with NC gases are used in this assessment. We assessed the special model for film condensation of TRACE 5.0-patch4 against the data of the reflux condensation test in the presence of NC gases. The special condensation model of TRACE provides a reasonable estimate of HTC with good agreement at the low inlet steam flow rate

Implementation of non-condensable gases condensation suppression model into the WCOBRA/TRAC-TF2 LOCA safety evaluation code

Energy Technology Data Exchange (ETDEWEB)

Liao, J.; Cao, L.; Ohkawa, K.; Frepoli, C. [LOCA Integrated Services I, Westinghouse Electric Company, 1000 Westinghouse Drive, Cranberry Township, PA 16066 (United States)

2012-07-01

The non-condensable gases condensation suppression model is important for a realistic LOCA safety analysis code. A condensation suppression model for direct contact condensation was previously developed by Westinghouse using first principles. The model is believed to be an accurate description of the direct contact condensation process in the presence of non-condensable gases. The Westinghouse condensation suppression model is further revised by applying a more physical model. The revised condensation suppression model is thus implemented into the WCOBRA/TRAC-TF2 LOCA safety evaluation code for both 3-D module (COBRA-TF) and 1-D module (TRAC-PF1). Parametric study using the revised Westinghouse condensation suppression model is conducted. Additionally, the performance of non-condensable gases condensation suppression model is examined in the ACHILLES (ISP-25) separate effects test and LOFT L2-5 (ISP-13) integral effects test. (authors)

Effect of flow velocity on the process of air-steam condensation in a vertical tube condenser

Science.gov (United States)

Havlík, Jan; Dlouhý, Tomáš

2018-06-01

This article describes the influence of flow velocity on the condensation process in a vertical tube. For the case of condensation in a vertical tube condenser, both the pure steam condensation process and the air-steam mixture condensation process were theoretically and experimentally analyzed. The influence of steam flow velocity on the value of the heat transfer coefficient during the condensation process was evaluated. For the condensation of pure steam, the influence of flow velocity on the value of the heat transfer coefficient begins to be seen at higher speeds, conversely, this effect is negligible at low values of steam velocity. On the other hand, for the air-steam mixture condensation, the influence of flow velocity must always be taken into account. The flow velocity affects the water vapor diffusion process through non-condensing air. The presence of air significantly reduces the value of the heat transfer coefficient. This drop in the heat transfer coefficient is significant at low velocities; on the contrary, the decrease is relatively small at high values of the velocity.

Condensation: the new deal; Condensation: la nouvelle donne

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-06-01

The principle of condensation boilers is based on the recovery of the latent heat of the steam generated by the combustion of natural gas. This technology was introduced in France at the end of the 80's but failed in its promise because of the complexity of the equipments available at that time. Today, constructors' offer is more mature and reliable and the context has changed. This technology can conciliate three goals: a mastery of energy consumptions, the comfort of the user and the respect of environment. This meeting organized by the research center of Gaz de France (Cegibat), was a good opportunity to makes a status of the market of individual condensation systems in France and in Europe, to present the situation of this technology today and the 10 golden rules for the fitting and maintenance of individual condensation boilers, and to present some technical references, examples and results of today's offer. (J.S.)

Born-Kothari Condensation for Fermions

Directory of Open Access Journals (Sweden)

Arnab Ghosh

2017-09-01

Full Text Available In the spirit of Bose–Einstein condensation, we present a detailed account of the statistical description of the condensation phenomena for a Fermi–Dirac gas following the works of Born and Kothari. For bosons, while the condensed phase below a certain critical temperature, permits macroscopic occupation at the lowest energy single particle state, for fermions, due to Pauli exclusion principle, the condensed phase occurs only in the form of a single occupancy dense modes at the highest energy state. In spite of these rudimentary differences, our recent findings [Ghosh and Ray, 2017] identify the foregoing phenomenon as condensation-like coherence among fermions in an analogous way to Bose–Einstein condensate which is collectively described by a coherent matter wave. To reach the above conclusion, we employ the close relationship between the statistical methods of bosonic and fermionic fields pioneered by Cahill and Glauber. In addition to our previous results, we described in this mini-review that the highest momentum (energy for individual fermions, prerequisite for the condensation process, can be specified in terms of the natural length and energy scales of the problem. The existence of such condensed phases, which are of obvious significance in the context of elementary particles, have also been scrutinized.

Condensation in Nanoporous Packed Beds.

Science.gov (United States)

Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

2016-05-10

In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization.

Comparison of Heat Transfer Coefficients of Silver Coated and Chromium Coated Copper Tubes of Condenser in Dropwise Condensation

OpenAIRE

Er. Shivesh Kumar; Dr. Amit Kumar

2016-01-01

Since centuries steam is being used in power generating system. The steam leaving the power unit is reconverted into water in a condenser designed to transfer heat from the steam to the cooling water as rapidly and as efficiently as possible. The efficiency of condenser depends on rate of condensation and mode of condensation of steam in the condenser. The increase in efficiency of the condenser enhances the heat transfer co-efficient which in turn results in economic design of condenser and ...

Bio-oil fractionation and condensation

Science.gov (United States)

Brown, Robert C; Jones, Samuel T; Pollard, Anthony

2013-07-02

A method of fractionating bio-oil vapors which involves providing bio-oil vapors comprising bio-oil constituents is described. The bio-oil vapors are cooled in a first stage which comprises a condenser having passages for the bio-oil separated by a heat conducting wall from passages for a coolant. The coolant in the condenser of the first stage is maintained at a substantially constant temperature, set at a temperature in the range of 75 to 100.degree. C., to condense a first liquid fraction of liquefied bio-oil constituents in the condenser of the first stage. The first liquid fraction of liquified bio-oil constituents from the condenser in the first stage is collected. Also described are steps for subsequently recovering further liquid fractions of liquefied bio-oil constituents. Particular compositions of bio-oil condensation products are also described.

Condenser performance monitoring and cleaning

International Nuclear Information System (INIS)

Walden, J.V.

1998-01-01

The main condenser at Ginna Station was retubed from admiralty brass to 316 stainless steel. A condenser performance monitoring spreadsheet was developed using EPRI guidelines after fouling was discovered. PEPSE computer models were used to determine the power loss and confirm the spreadsheet results. Cleaning of the condenser was performed using plastic scrubbers. Condenser performance improved dramatically following the cleaning. PEPSE, condenser spreadsheet performance, and actual observed plant data correlated well together. The fouling mechanism was determined to be a common lake bacteria and fungus growth which was combined with silt. Chlorination of the circulating water system at the allowable limits is keeping the biofouling under control

Chromosome condensation and segmentation

International Nuclear Information System (INIS)

Viegas-Pequignot, E.M.

1981-01-01

Some aspects of chromosome condensation in mammalians -humans especially- were studied by means of cytogenetic techniques of chromosome banding. Two further approaches were adopted: a study of normal condensation as early as prophase, and an analysis of chromosome segmentation induced by physical (temperature and γ-rays) or chemical agents (base analogues, antibiotics, ...) in order to show out the factors liable to affect condensation. Here 'segmentation' means an abnormal chromosome condensation appearing systematically and being reproducible. The study of normal condensation was made possible by the development of a technique based on cell synchronization by thymidine and giving prophasic and prometaphasic cells. Besides, the possibility of inducing R-banding segmentations on these cells by BrdU (5-bromodeoxyuridine) allowed a much finer analysis of karyotypes. Another technique was developed using 5-ACR (5-azacytidine), it allowed to induce a segmentation similar to the one obtained using BrdU and identify heterochromatic areas rich in G-C bases pairs [fr

Characteristic aspects of pion-condensed phases

International Nuclear Information System (INIS)

Takatsuka, Tatsuyuki; Tamagaki, Ryozo; Tatsumi, Toshitaka.

1993-01-01

Characteristic aspects of pion-condensed phases are described in a simple model, for the system involving only nucleons and pions which interact through the π-N P-wave interaction. We consider one typical version in each of three kinds of pion condensation; the one of neutral pions (π 0 ), the one of charged pions (π C ) and the combined one in which both the π 0 and π C condensations are coexistent. Emphasis is put on the description to clarify the novel structures of the nucleon system which are realized in the pion-condensed phases. At first, it is shown that the π 0 condensation is equivalent to the particular nucleonic phase realized by a structure change of the nucleon system, where the attractive first-order effect of the one-pion-exchange (OPE) tensor force is brought about coherently. The aspects of this phase are characterized by the layered structure with a specific spin-isospin order with one-dimensional localization (named the ALS structure in short), which provides the source function for the condensed π 0 field. We utilize both descriptions with use of fields and potentials for the π 0 condensation. Next, the π C condensation realized in neutron-rich matter is described by adopting a version of the traveling condensed wave. In this phase, the nucleonic structure becomes the Fermi gas consisting of quasi-neutrons described by a superposition of neutron and proton. In this sense the structure change of the nucleon system for the π C condensation is moderate, and the field description is suitable. Finally, we describe a coexistent pion condensation, in which both the π 0 and π C condensations coexist without interference in such a manner that the π C condensation develops in the ALS structure. The model adopted here provides us with the characteristic aspects of the pion-condensed phases persisting in the realistic situation, where other ingredients affecting the pion condensation are taken into account. (author)

Systematic text condensation

DEFF Research Database (Denmark)

Malterud, Kirsti

2012-01-01

To present background, principles, and procedures for a strategy for qualitative analysis called systematic text condensation and discuss this approach compared with related strategies.......To present background, principles, and procedures for a strategy for qualitative analysis called systematic text condensation and discuss this approach compared with related strategies....

Avaliação in vitro da efetividade de polimerização da resina acrílica dental ativada através de energia de microondas, quando em contato com metal Use of microwave energy for processing acrylic resin near metal

Directory of Open Access Journals (Sweden)

Katia Olmedo BRAUN

1998-04-01

Full Text Available Com o objetivo de verificar a efetividade da energia de microondas na polimerização da resina acrílica próxima ao metal, foram confeccionados 36 corpos-de-prova cilíndricos com 30,0 mm de diâmetro x 4,0 mm de espessura, contendo no seu interior uma sela metálica com 28,0 mm x 8,0 mm x 0,5 mm, divididos aleatoriamente em 3 grupos e submetidos aos seguintes processamentos: G1 resina Clássico polimerizada em ciclo curto; G2 resina Acron-MC polimerizada em forno de microondas por 3 minutos a 500 W; G3 resina Clássico polimerizada em forno de microondas por 3 minutos a 500 W. Após a polimerização, cada amostra foi dividida em duas partes aproximadamente iguais, sendo que uma das partes foi utilizada para a avaliação de monômero residual, enquanto a outra foi submetida aos testes de dureza e porosidade. A dosagem de monômero liberada na água durante doze dias consecutivos foi avaliada através da espectrofotometria. A dureza Knoop foi verificada nas distâncias de 50, 100, 200, 400 e 800 mm da sela metálica, e a porosidade interna e externa foi avaliada a olho nu e com auxílio de microscópio com aumento de 100 X. Diante dos resultados obtidos, concluiu-se que a energia de microondas pode ser utilizada para a polimerização da resina acrílica contendo sela metálica no seu interior e que as resinas acrílicas convencionais, quando polimerizadas através da energia de microondas, apresentaram maior quantidade de poros.The conventional method to process acrylic resin is a time consuming step to construct removable prosthodontics. Microwave energy could provide a solution, but there are still questions regarding this process taking place in the presence of metal. The aim of this study was, therefore, to compare residual monomer, microhardness and porosity of two acrylic resins cured by different methods in the presence of a metal framework. The conditions evaluated were: Group 1 - Acrylic resin Clássico, short cycle heatcured for 3

Steam generators, turbines, and condensers. Volume six

International Nuclear Information System (INIS)

Anon.

1986-01-01

Volume six covers steam generators (How steam is generated, steam generation in a PWR, vertical U-tube steam generators, once-through steam generators, how much steam do steam generators make?), turbines (basic turbine principles, impulse turbines, reaction turbines, turbine stages, turbine arrangements, turbine steam flow, steam admission to turbines, turbine seals and supports, turbine oil system, generators), and condensers (need for condensers, basic condenser principles, condenser arrangements, heat transfer in condensers, air removal from condensers, circulating water system, heat loss to the circulating water system, factors affecting condenser performance, condenser auxiliaries)

Relationship between filler content and selected mechanical properties of six microhybrid composites = Relação entre o conteúdo de carga e propriedades mecânicas de seis resinas compostas microhíbridas

Directory of Open Access Journals (Sweden)

Mota, Eduardo Gonçalves

2011-01-01

Conclusão: A resina Z2 teve a maior resistência à compressão; Z2 e TC apresentaram maiores módulo de elasticidade, VHN e conteúdo de carga em peso. O conteúdo de carga em peso teve uma forte influência nas propriedades mecânicas avaliadas (0,78

A CFD study of wave influence on film steam condensation in the presence of non-condensable gas

Energy Technology Data Exchange (ETDEWEB)

Wang, Xianmao, E-mail: xm-wang11@mails.tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Chang, Huajian, E-mail: changhj@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Corradini, Michael, E-mail: corradini@engr.wisc.edu [Department of Engineering Physics, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, WI 53706 (United States)

2016-08-15

Highlights: • A condensation model is incorporated in the ANSYS FLUENT. • Different turbulence models are evaluated for flows over wavy surfaces. • Wavy surfaces with and without moving velocities are used to model the wave. • Various wavy surfaces with different wave heights and wavelengths are selected. • Wave influence on film steam condensation is investigated. - Abstract: Steam condensation plays an important role in removing heat from the containment of a nuclear plant during postulated accidents. However, due to the presence of non-condensable gases such as air and hydrogen in the containment, the condensation rate can decrease dramatically. Under certain conditions, the condensate film on the cold containment walls can affect the overall heat transfer rate. The wavy interface of the condensate film is a factor and is usually believed to enhance the condensation rate, since the waves can both increase the interfacial area and disturb the non-condensable gas boundary layer. However, it is not clear how to properly account for this factor and what is its quantitative influence in experiments. In this work, a CFD approach is applied to study the wave effects on film condensation in the presence of non-condensable gas. Wavy surfaces with and without moving velocities are used to replace the wavy interface of the falling film. A condensation model is incorporated in the ANSYS FLUENT simulation and a realizable k–ε turbulence model is applied. Various wavy surfaces with different wave heights and wavelengths are selected to conduct numerical experiments with a wide range of gas velocities. The results show that the wave structure can enhance condensation rate up to ten percent mainly due to the alteration of local flow structures in the gas phase. The increments of the condensation rate due to the wavy interface can vary with different gas velocities. The investigation shows that a multiplication factor accounts for the wave effects on film

Assessment of horizontal in-tube condensation models using MARS code. Part I: Stratified flow condensation

Energy Technology Data Exchange (ETDEWEB)

Jeon, Seong-Su [Department of Engineering Project, FNC Technology Co., Ltd., Bldg. 135-308, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Department of Nuclear Engineering, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Hong, Soon-Joon, E-mail: sjhong90@fnctech.com [Department of Engineering Project, FNC Technology Co., Ltd., Bldg. 135-308, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Park, Ju-Yeop; Seul, Kwang-Won [Korea Institute of Nuclear Safety, 19 Kuseong-dong, Yuseong-gu, Daejon (Korea, Republic of); Park, Goon-Cherl [Department of Nuclear Engineering, Seoul National University, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

2013-01-15

Highlights: Black-Right-Pointing-Pointer This study collected 11 horizontal in-tube condensation models for stratified flow. Black-Right-Pointing-Pointer This study assessed the predictive capability of the models for steam condensation. Black-Right-Pointing-Pointer Purdue-PCCS experiments were simulated using MARS code incorporated with models. Black-Right-Pointing-Pointer Cavallini et al. (2006) model predicts well the data for stratified flow condition. Black-Right-Pointing-Pointer Results of this study can be used to improve condensation model in RELAP5 or MARS. - Abstract: The accurate prediction of the horizontal in-tube condensation heat transfer is a primary concern in the optimum design and safety analysis of horizontal heat exchangers of passive safety systems such as the passive containment cooling system (PCCS), the emergency condenser system (ECS) and the passive auxiliary feed-water system (PAFS). It is essential to analyze and assess the predictive capability of the previous horizontal in-tube condensation models for each flow regime using various experimental data. This study assessed totally 11 condensation models for the stratified flow, one of the main flow regime encountered in the horizontal condenser, with the heat transfer data from the Purdue-PCCS experiment using the multi-dimensional analysis of reactor safety (MARS) code. From the assessments, it was found that the models by Akers and Rosson, Chato, Tandon et al., Sweeney and Chato, and Cavallini et al. (2002) under-predicted the data in the main condensation heat transfer region, on the contrary to this, the models by Rosson and Meyers, Jaster and Kosky, Fujii, Dobson and Chato, and Thome et al. similarly- or over-predicted the data, and especially, Cavallini et al. (2006) model shows good predictive capability for all test conditions. The results of this study can be used importantly to improve the condensation models in thermal hydraulic code, such as RELAP5 or MARS code.

Off gas condenser performance modelling

International Nuclear Information System (INIS)

Cains, P.W.; Hills, K.M.; Waring, S.; Pratchett, A.G.

1989-12-01

A suite of three programmes has been developed to model the ruthenium decontamination performance of a vitrification plant off-gas condenser. The stages of the model are: condensation of water vapour, NO x absorption in the condensate, RuO 4 absorption in the condensate. Juxtaposition of these stages gives a package that may be run on an IBM-compatible desktop PC. Experimental work indicates that the criterion [HNO 2 ] > 10 [RuO 4 ] used to determine RuO 4 destruction in solution is probably realistic under condenser conditions. Vapour pressures of RuO 4 over aqueous solutions at 70 o -90 o C are slightly lower than the values given by extrapolating the ln K p vs. T -1 relation derived from lower temperature data. (author)

Potencial de produção de óleo-resina de copaíba (Copaifera spp de populações naturais do sudoeste da Amazônia Oil resin production potential of Copaifera spp natural populations in the Southwestern Brazilian Amazon

Directory of Open Access Journals (Sweden)

Onofra Cleuza Rigamonte-Azevedo

2006-08-01

Full Text Available O potencial de produção de óleo-resina extraído de Copaífera spp foi avaliado em duas populações naturais do sudoeste da Amazônia brasileira (municípios de Tarauacá e Xapuri, nos anos de 2000 e 2001. Foram selecionadas 388 árvores adultas de copaíbas das duas populações, sendo identificados em cada árvore o diâmetro à altura do peito (DAP, a produção de óleo-resina, a posição da árvore no relevo local (baixio ou terra firme e a tipologia florestal local (floresta aberta ou densa, além do nome regional da copaíba, com base em características morfológicas da casca: Copaifera reticulata: copaíba-branca, vermelha, amarela e preta e Copaifera paupera: mari-mari. Os resultados indicam que a copaíba mari-mari possui maior proporção de indivíduos produtivos (80%, enquanto os demais morfotipos apresentaram apenas de 22 a 40% de seus indivíduos produtivos. Com relação a todas as árvores amostradas, a produção de óleo-resina variou de 0 a 18 L árvore-1, com a copaíba mari-mari tendo a maior produção média (1,33 L árvore-1, porém sem diferir significativamente dos demais morfotipos. Após excluir da análise as árvores não produtivas, a copaíba-preta apresentou significativamente a maior produção média de óleo-resina (2,92 L árvore-1. A tipologia florestal, posição da árvore no relevo e o DAP não se mostraram relacionados a produção de óleo-resina.The potential for production of oil resin extracted from Copaifera spp natural populations was studied in two natural populations (municipalities of Tarauacá and Xapuri in the Southwestern Brazilian Amazon, in 2000 and 2001. Three hundred and eighty-eight adult trees were selected within these two populations. DBH, oil production, topographic position, regional common names (based on bark appearance; White, Red, Yellow, Black for Copaifera reticulata, and Mari-Mari for C. paupera and forest typology were recorded for each individual. Copaiba Mari

Biochemical analysis of the Hormoconis resinae fungal mycelium in the corrosion of aeronautical aluminium alloys

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Araya, R.

2007-06-01

Full Text Available Biochemical analyses of the Hormoconis resinae fungal mycelium would explain behaviour differences of corrosive and non-corrosive strains on Al and its aeronautical alloys. In previous works its aggressiveness had been studied through SEM-EDX surface analysis, electrochemical techniques and immersion testing. In this paper separation of the proteins of the mycelium produced by a non-corrosive strain and its culture along three generations was performed. Cultures were prepared in batch in the presence and absence of pure Al and AA 2024, AA 7005 and AA 7075 alloys. The mycelia grown throughout the three generations increasingly
recovered usual characteristics at the third replication, included their corrosiveness on Al and its alloys previously shown by all our strains. Amongst the bio-molecule fractions isolated and analysed during this preliminary study only the proteins revealed changes with the generation grown. When this fungal strain was cultured in the presence of alloy metal sheets electrophoresis of the protean fraction was correlative with the distinct mycelia behaviour observed, including corrosiveness on Al and its alloys.

Las diferencias entre el comportamiento corrosivo y no corrosivo de una cepa del hongo Hormoconis resinae sobre aluminio y sus aleaciones aeronáuticas se explicarían a través de análisis bioquímicos del micelio. En trabajos previos, el comportamiento corrosivo se estudió mediante análisis de superficie SEM-EDX, técnicas electroquímicas y ensayos de inmersión. En este trabajo, se llevó a cabo la separación de proteínas del micelio producido por una cepa que perdió su corrosividad y su cultivo a través de tres generaciones. Cultivos en batch, en presencia y ausencia de aluminio y sus aleaciones AA 2024, AA 7005 y AA 7075, a través de tres generaciones del micelio crecido, fueron recuperando sus características, incluida su habitual corrosividad, en la tercera replicaci

Condensate from a two-stage gasifier

DEFF Research Database (Denmark)

Bentzen, Jens Dall; Henriksen, Ulrik Birk; Hindsgaul, Claus

2000-01-01

Condensate, produced when gas from downdraft biomass gasifier is cooled, contains organic compounds that inhibit nitrifiers. Treatment with activated carbon removes most of the organics and makes the condensate far less inhibitory. The condensate from an optimised two-stage gasifier is so clean...... that the organic compounds and the inhibition effect are very low even before treatment with activated carbon. The moderate inhibition effect relates to a high content of ammonia in the condensate. The nitrifiers become tolerant to the condensate after a few weeks of exposure. The level of organic compounds...... and the level of inhibition are so low that condensate from the optimised two-stage gasifier can be led to the public sewer....

Assessment of RELAP5/MOD3.3 condensation models for the tube bundle condensation in the PCCS of ESBWR

International Nuclear Information System (INIS)

Zhou, W.; Wolf, B.; Revankar, S.T.

2011-01-01

The passive containment condenser system (PCCS) in an ESBWR reactor consists of vertical tube bundle submerged in a large pool of water. The condensation model for the PCCS in a thermalhydraulics code RELAP5/MOD3.3 consists of the default Nusselt model and an alternate condensation model from UCB condensation correlation. An assessment of the PCCS condensation model in RELAP5/MOD3.3 was carried out using experiments conducted on a single tube and tube bundle PCCS tests at Purdue University. The experimental conditions were simulated with the default and the alternate condensation models in the REALP5/MOD3.3 beta version of the code. The default model and the UCB model (alternate model) give quite different results on condensation heat transfer for the PCCS. The default model predicts complete condensation well whereas the UCB model predicts the through flow condensation well. Based on this study it was found that none of the models in REALP5 can predict complete condensation as well as the through flow condensation well. (author)

Assessment of RELAP5/MOD3.3 condensation models for the tube bundle condensation in the PCCS of ESBWR

Energy Technology Data Exchange (ETDEWEB)

Zhou, W., E-mail: wenzzhou@cityu.edu.hk [Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong (China); Wolf, B. [Purdue University, West Lafayette, IN 47907 (United States); Revankar, S. [Purdue University, West Lafayette, IN 47907 (United States); POSTECH, Pohang (Korea, Republic of)

2013-11-15

The passive containment condenser system (PCCS) in an ESBWR reactor consists of vertical tube bundle submerged in a large pool of water. The condensation model for the PCCS in a thermalhydraulics code RELAP5/MOD3.3 consists of the default Nusselt model and an alternate condensation model from UCB condensation correlation. An assessment of the PCCS condensation model in RELAP5/MOD3.3 was carried out using experiments conducted on a single tube and tube bundle PCCS tests at Purdue University. The experimental conditions were simulated with the default and the alternate condensation models in the REALP5/MOD3.3 beta version of the code. The default model and the UCB model (alternate model) give quite different results on condensation heat transfer for the PCCS. The default model predicts complete condensation well whereas the UCB model predicts the through flow condensation well. Based on this study it was found that none of the models in REALP5 can predict complete condensation as well as the through flow condensation well.

The Effect of Capillary Number on a Condensate Blockage in Gas Condensate Reservoirs

OpenAIRE

Saifon DAUNGKAEW; Alain C GRINGARTEN

2004-01-01

In the petroleum industry, gas condensate reservoirs are becoming more common as exploration targets. However, there is a lack of knowledge of the reservoir behaviour mainly due to its complexity in the near wellbore region, where two phases, i.e. reservoir gas and condensate coexist when the wellbore pressure drops below the dew point pressure. The condensation process causes a reduction of the gas productivity (1). It has been reported in the literature that there is an increasing gas mobil...

Resistencia al cizallamiento de una resina compuesta al aplicar diferentes agentes blanqueadores y su efecto sobre la microestructura del esmalte

OpenAIRE

Cornejo Peña, María Antonieta

2014-01-01

Muchos han sido los estudios que se han reportado acerca del efecto de sustancias aclaradoras sobre la adhesión y estructura del esmalte, sin embargo, poco se ha reportado sobre las alteraciones morfológicas de la estructura exterior del esmalte después del blanqueamiento. A pesar de la reducción de la microdureza del esmalte se ha informado que esta alteración no es sólo por el procedimiento de blanqueamiento, sino también por el pH de la fórmula utilizada. Algunos estudios no han encontrado...

Efeito da técnica de polimento na topografia de superfície e na transmitância da resina composta

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Marina Moura de Azevedo Souza

Full Text Available Introdução: Clinicamente, é comum observar os efeitos de estratificação de restaurações de compósito apenas após o polimento. Objetivo: Avaliar o efeito da técnica de polimento na transmitância de luz e na topografia de superfície de uma resina composta. Material e método: Amostras da resina Filtek Z-350 XT (cor A1E foram confeccionadas em matriz metálica. Uma das superfícies das amostras recebeu acabamento com brocas de 12 lâminas e polimento através de uma das seguintes técnicas: SL (Sof-Lex, EH (Enhance e DH (DHPro. Ausência de polimento foi usada como controle. Após o polimento, as amostras deviam apresentar espessura final de 1 mm. A transmitância de luz foi avaliada através do espectrofotômetro, sendo considerada apenas a luz no espectro visível. A topografia de superfície foi avaliada através de interferometria a laser, com os parâmetros Sdq (híbrido, St (amplitude máxima e As (média de picos e vales. Os dados (n=5 foram submetidos a ANOVA e teste SNK. O teste de correlação de Pearson correlacionou Sdq, St e Sa à transmitância (α=0,05. Resultado: Todos os sistemas de polimento aumentaram a transmitância de luz em relação ao controle, não havendo diferença entre estes. Apenas as amostras polidas com SL e DH apresentaram maiores valores de Sdq que o Controle. Já para os parâmetros St e Sa, EH mostrou menores valores que o controle. Sdq e St mostraram correlação significativa com transmitância. Conclusão: Todos os sistemas de polimento foram efetivos em aumentar a transmitância, sendo a redução dos valores Sdq e St relacionada a esta modificação.

Ghost condensate and generalized second law

International Nuclear Information System (INIS)

Mukohyama, Shinji

2009-01-01

Dubovsky and Sibiryakov recently proposed a scenario in which particles of different species propagate with different speeds due to their direct couplings to ghost condensate. It was argued that this extended version of ghost condensate allows a gedanken experiment leading to violation of the generalized second law. However, in the original ghost condensate scenario, difference in propagation speeds is suppressed by M 2 /M Pl 2 , where M is the order parameter of spontaneous Lorentz breaking and M Pl is the Planck scale. In this case the energy transfer necessary for the gedanken experiment is so slow that the timescale of decrease of entropy, if any, is always longer than the Jeans timescale of ghost condensate. Hence the generalized second law is not violated by the gedanken experiment in the original ghost condensate scenario. This conclusion trivially extends to gauged ghost condensation by taking into account accretion of gauged ghost condensate into a black hole.

Black holes in the ghost condensate

International Nuclear Information System (INIS)

Mukohyama, Shinji

2005-01-01

We investigate how the ghost condensate reacts to black holes immersed in it. A ghost condensate defines a hypersurface-orthogonal congruence of timelike curves, each of which has the tangent vector u μ =-g μν ∂ ν φ. It is argued that the ghost condensate in this picture approximately corresponds to a congruence of geodesics. In other words, the ghost condensate accretes into a black hole just like a pressureless dust. Correspondingly, if the energy density of the ghost condensate at large distance is set to an extremely small value by cosmic expansion then the late-time accretion rate of the ghost condensate should be negligible. The accretion rate remains very small even if effects of higher derivative terms are taken into account, provided that the black hole is sufficiently large. It is also discussed how to reconcile the black-hole accretion with the possibility that the ghost condensate might behave like dark matter

Comparação da influência entre tempos de polimerização em resinas compostas polimerizadas com LED e Luz Incandescente Comparison of the influence of curing times applied to composite resins cured with LED and Incandescent Light

Directory of Open Access Journals (Sweden)

Michele P. M. Ulhoa

2007-09-01

Full Text Available O propósito deste trabalho é fazer uma comparação entre resinas poliméricas dentárias, polimerizadas por aparelhos baseados em lâmpada halógena e diodo emissor de Luz (LED, utilizando-se o método do disco retificado aperfeiçoado para odontologia e os respectivos valores de microdureza. Foram realizados testes em amostras de resinas compostas de 5 diferentes marcas, polimerizadas a tempos de 10, 20 e 40 s, pelos dois aparelhos. A análise estatística dos valores de microdureza e agressividade permitiu concluir que estatisticamente não há correlação entre essas propriedades. Na análise de microdureza, a heterogeneidade característica do material implicou em resultados com valores de desvio padrão relativamente altos, de forma que não foi encontrada diferença estatística entre as amostras avaliadas. Na análise estatística dos ensaios baseados no método do disco retificado, a resina que apresentou maior desgaste nos ensaios, foi a Tetric Ceram, polimerizada pelo aparelho de LED por 10 s, cujo valor médio de agressividade obtido foi 0,170 mm³/N.m. A resina que sofreu menor desgaste foi a Charisma, polimerizada por Lâmpada Incandescente, por um tempo de 20 s, cuja média dos valores de agressividade foi 0,057 mm³/N.m.The purpose of this work was to compare polymeric dental resins cured with halogen lamp and with light emission diode (LED devices, using the grinding disk method customized for dentistry and the corresponding microhardness values. Tests were carried out on resin samples of five brands, which were cured for 10, 20 and 40 s with the two devices. The analysis of microhardness and aggressiveness has allowed us to conclude that there is no correlation between these properties. In Microhardness tests, the material heterogeneity has produced relative high standard deviation values and has not shown statistical differences between the analyzed samples. In the statistical analysis for the results with the grinding disk

Effect of repeated microwave disinfection on surface roughness and baseplate adaptation of denture resins polymerized by different techniques = Efeito da desinfecção repetida por microondas sobre rugosidade superficial e adaptação de bases de resinas polimerizadas por diferentes técnicas

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Campos, Maria Agnese Pinto de

2009-01-01

Full Text Available Objetivo: Avaliar o efeito cumulativo de dois protocolos de desinfecção por energia de micro-ondas (Protocolo 1: 690 W/6 min; Protocolo 2: 345 W/6 min na rugosidade superficial (Ra e adaptação de bases de dentadura de duas resinas polimerizadas por micro-ondas (Onda Cryl ou banho de água quente (QC-20. Metodologia: Para Ra, espécimes retangulares foram fabricados e divididos de acordo com o tratamento de desinfecção (n=8/grupo: 1 Controle (sem desinfecção, 2 Protocolo 1, e 3 Protocolo 2. Para medir Ra usou-se um rugosímetro no baseline (T0 e após 2 procedimentos de desinfecção (T1, T2 com intervalo de 7 dias de imersão em água destilada. Para avaliar a estabilidade dimensional, bases maxilares foram divididas nos 3 grupos (n=6 e a adaptação foi medida por pesagem de uma película de silicone que reproduzia o espaço entre a base de resina e um modelo-mestre metálico. Resultados: Para Ra, houve interação significativa entre tipo de resina e técnica de polimerização, tratamento de desinfecção, e número de procedimentos desinfecção (P<0,001. Os grupos Protocolo 2 e controle apresentaram aumento semelhante de Ra ao longo do tempo, mas os grupos Protocolo 1 tiveram uma redução significativa de Ra em T2. A adaptação da base foi afetada por uma interação significante entre tratamento de desinfecção e número de procedimentos de desinfecção (P<0,001; o Protocolo 1 apresentou a maior média em T2. Conclusão: Onda Cryl teve maiores alterações de Ra e adaptação que QC-20. O Protocolo 1 promoveu dano geral para ambos os tipos de resina após dois procedimentos de desinfecção

Physics of condensed matter

CERN Document Server

Misra, Prasanta K

2012-01-01

Physics of Condensed Matter is designed for a two-semester graduate course on condensed matter physics for students in physics and materials science. While the book offers fundamental ideas and topic areas of condensed matter physics, it also includes many recent topics of interest on which graduate students may choose to do further research. The text can also be used as a one-semester course for advanced undergraduate majors in physics, materials science, solid state chemistry, and electrical engineering, because it offers a breadth of topics applicable to these majors. The book be

Pion condensation and neutron star dynamics

International Nuclear Information System (INIS)

Kaempfer, B.

1983-01-01

The question of formation of pion condensate via a phase transition in nuclear matter, especially in the core of neutron stars is reviewed. The possible mechanisms and the theoretical restrictions of pion condensation are summarized. The effects of ultradense equation of state and density jumps on the possible condensation phase transition are investigated. The possibilities of observation of condensation process are described. (D.Gy.)

Optimal design of condenser weight

International Nuclear Information System (INIS)

Zheng Jing; Yan Changqi; Wang Jianjun

2011-01-01

The condenser is an important component in nuclear power plants, which dimension and weight will effect the economical performance and the arrangement of the nuclear power plants. In this paper, the calculation model is established according to the design experience. The corresponding codes are also developed, and the sensitivity of design parameters which influence the condenser weight is analyzed. The present design optimization of the condenser, taking the weight minimization as the objective, is carried out with the self-developed complex-genetic algorithm. The results show that the reference condenser design is far from the best scheme, and also verify the feasibility of the complex-genetic algorithm. (authors)

The physics of exciton-polariton condensates

CERN Document Server

Lagoudakis, Konstantinos

2013-01-01

In 2006 researchers created the first polariton Bose-Einstein condensate at 19K in the solid state. Being inherently open quantum systems, polariton condensates open a window into the unpredictable world of physics beyond the “fifth state of matter”: the limited lifetime of polaritons renders polariton condensates out-of-equilibrium and provides a fertile test-bed for non-equilibrium physics. This book presents an experimental investigation into exciting features arising from this non-equilibrium behavior. Through careful experimentation, the author demonstrates the ability of polaritons to synchronize and create a single energy delocalized condensate. Under certain disorder and excitation conditions the complete opposite case of coexisting spatially overlapping condensates may be observed. The author provides the first demonstration of quantized vortices in polariton condensates and the first observation of fractional vortices with full phase and amplitude characterization. Finally, this book investigate...

Avaliação do efeito de tratamentos superficiais sobre a força de adesão de braquetes em provisórios de resina acrílica Assessment of the effect of different surface treatments on the bond strength of brackets bonded to acrylic resin

Directory of Open Access Journals (Sweden)

Deise Lima Cunha Masioli

2011-02-01

Full Text Available OBJETIVO: avaliar a influência do tratamento de superfície de resinas acrílicas na resistência ao cisalhamento de braquetes colados com resina composta. MÉTODOS: foram confeccionados 140 discos de resina acrílica autopolimerizável (Duralay®, divididos aleatoriamente em 14 grupos (n=10. Em cada grupo, os corpos de prova receberam um tipo diferente de tratamento de superfície: grupo 1 = sem tratamento de superfície (controle; grupo 2 = silano; grupo 3 = jato de óxido de alumínio (JOA; grupo 4 = JOA + silano; grupo 5 = broca diamantada; grupo 6 = broca diamantada+ silano; grupo 7 = ácido fluorídrico; grupo 8 = ácido fluorídrico + silano; grupo 9 = ácido fosfórico; grupo 10 = ácido fosfórico + silano; grupo 11 = monômero de metilmetacrilato (MMA; grupo 12 = MMA + silano; grupo 13 = Plastic conditioner (Reliance®; grupo 14 = Plastic conditioner (Reliance® + silano. Após o preparo de superfície, os corpos de prova foram analizados através da rugosimetria. Posteriormente, foram colados braquetes (Morelli® de incisivo central "standard edgewise" com resina fotopolimerizável Transbond XT®; de acordo com as instruções do fabricante. RESULTADOS: o agente umectante à base de silano não teve um efeito estatisticamente significativo sobre os valores de força de adesão; os tratamentos com JOA e broca produziram maiores mudanças topográficas na superfície da resina acrílica, bem como os maiores valores de rugosidade; observou-se uma correlação não linear entre a força de adesão e a rugosidade de superfície; tratamentos com monômero e JOA resultaram nas maiores forças de adesão. CONCLUSÕES: o silano não foi capaz de aumentar a força de adesão entre braquete e resina acrílica. Sugere-se mais estudos sobre este tema, pois a força de adesão obtida foi muito baixa.OBJECTIVE: To evaluate the influence of the surface treatment of acrylic resins on the shear bond strength of brackets bonded with composite resin

Effect of post-polymerization heat treatments on the cytotoxicity of two denture base acrylic resins Efeito de tratamentos térmicos após a polimerização sobre a citotoxicidade de duas resinas acrílicas para base de próteses

Directory of Open Access Journals (Sweden)

Janaina Habib Jorge

2006-06-01

Full Text Available INTRODUCTION: Most denture base acrylic resins have polymethylmethacrylate in their composition. Several authors have discussed the polymerization process involved in converting monomer into polymer because adequate polymerization is a crucial factor in optimizing the physical properties and biocompatibility of denture base acrylic resins. To ensure the safety of these materials, in vitro cytotoxicity assays have been developed as preliminary screening tests to evaluate material biocompatibility. ³H-thymidine incorporation test, which measures the number of cells synthesizing DNA, is one of the biological assays suggested for cytotoxicity testing. AIM: The purpose of this study was to investigate, using ³H-thymidine incorporation test, the effect of microwave and water-bath post-polymerization heat treatments on the cytotoxicity of two denture base acrylic resins. MATERIALS AND METHODS: Nine disc-shaped specimens (10 x 1 mm of each denture base resin (Lucitone 550 and QC 20 were prepared according to the manufacturers' recommendations and stored in distilled water at 37ºC for 48 h. The specimens were assigned to 3 groups: 1 post-polymerization in a microwave oven for 3 min at 500 W; 2 post-polymerization in water-bath at 55º C for 60 min; and 3 without post-polymerization. For preparation of eluates, 3 discs were placed into a sterile glass vial with 9 mL of Eagle's medium and incubated at 37ºC for 24 h. The cytotoxic effect of the eluates was evaluated by ³H-thymidine incorporation. RESULTS: The results showed that the components leached from the resins were cytotoxic to L929 cells, except for the specimens heat treated in water bath (pINTRODUÇÃO: A maioria das resinas acrílicas utilizadas para confecção de bases de próteses é composta pelo polimetacilato de metila. Muitos autores têm discutido o processo de polimerização dessas resinas em relação à conversão do monômero em polímero devido a sua importância na melhora da

Transient direct-contact condensation on liquid droplets

International Nuclear Information System (INIS)

Pasamehmetoglu, K.O.; Nelson, R.A.

1987-01-01

In this paper, direct-contact condensation on subcooled liquid droplets is studied in two parts. In the first part, simple design correlations for the condensation in a steady environment are developed based upon a conduction model. These correlations include the convective heat-transfer coefficient, condensation rate, total condensation, and the droplet-thermalization time. In the second part of the paper, the effect of a time-dependent saturation temperature on the condensation process is investigated. A rapid decrease in saturation temperature is typical of condensation environments in which the steam-supply rate is limited and condensation-induced depressurization becomes important. Design correlations are developed for condensation in an environment in which the saturation temperature decreases linearly with time. These correlations are graphically compared to the design correlations of the first part through a quasi-steady approach. The error associated with this approach is quantified as a function of the rate of change of the saturation temperature

Use of fundamental condensation heat transfer experiments for the development of a sub-grid liquid jet condensation model

Energy Technology Data Exchange (ETDEWEB)

Buschman, Francis X., E-mail: Francis.Buschman@unnpp.gov; Aumiller, David L.

2017-02-15

Highlights: • Direct contact condensation data on liquid jets up to 1.7 MPa in pure steam and in the presence of noncondensable gas. • Identified a pressure effect on the impact of noncondensables to suppress condensation heat transfer not captured in existing data or correlations. • Pure steam data is used to develop a new correlation for condensation heat transfer on subcooled liquid jets. • Noncondensable data used to develop a modification to the renewal time estimate used in the Young and Bajorek correlation for condensation suppression in the presence of noncondensables. • A jet injection boundary condition, using a sub-grid jet condensation model, is developed for COBRA-IE which provides a more detailed estimate of the condensation rate on the liquid jet and allows the use of jet specific closure relationships. - Abstract: Condensation on liquid jets is an important phenomenon for many different facets of nuclear power plant transients and analyses such as containment spray cooling. An experimental facility constructed at the Pennsylvania State University, the High Pressure Liquid Jet Condensation Heat Transfer facility (HPLJCHT), has been used to perform steady-state condensation heat transfer experiments in which the temperature of the liquid jet is measured at different axial locations allowing the condensation rate to be determined over the jet length. Test data have been obtained in a pure steam environment and with varying concentrations of noncondensable gas. This data extends the available jet condensation data from near atmospheric pressure up to a pressure of 1.7 MPa. An empirical correlation for the liquid side condensation heat transfer coefficient has been developed based on the data obtained in pure steam. The data obtained with noncondensable gas were used to develop a correlation for the renewal time as used in the condensation suppression model developed by Young and Bajorek. This paper describes a new sub-grid liquid jet

Use of fundamental condensation heat transfer experiments for the development of a sub-grid liquid jet condensation model

International Nuclear Information System (INIS)

Buschman, Francis X.; Aumiller, David L.

2017-01-01

Highlights: • Direct contact condensation data on liquid jets up to 1.7 MPa in pure steam and in the presence of noncondensable gas. • Identified a pressure effect on the impact of noncondensables to suppress condensation heat transfer not captured in existing data or correlations. • Pure steam data is used to develop a new correlation for condensation heat transfer on subcooled liquid jets. • Noncondensable data used to develop a modification to the renewal time estimate used in the Young and Bajorek correlation for condensation suppression in the presence of noncondensables. • A jet injection boundary condition, using a sub-grid jet condensation model, is developed for COBRA-IE which provides a more detailed estimate of the condensation rate on the liquid jet and allows the use of jet specific closure relationships. - Abstract: Condensation on liquid jets is an important phenomenon for many different facets of nuclear power plant transients and analyses such as containment spray cooling. An experimental facility constructed at the Pennsylvania State University, the High Pressure Liquid Jet Condensation Heat Transfer facility (HPLJCHT), has been used to perform steady-state condensation heat transfer experiments in which the temperature of the liquid jet is measured at different axial locations allowing the condensation rate to be determined over the jet length. Test data have been obtained in a pure steam environment and with varying concentrations of noncondensable gas. This data extends the available jet condensation data from near atmospheric pressure up to a pressure of 1.7 MPa. An empirical correlation for the liquid side condensation heat transfer coefficient has been developed based on the data obtained in pure steam. The data obtained with noncondensable gas were used to develop a correlation for the renewal time as used in the condensation suppression model developed by Young and Bajorek. This paper describes a new sub-grid liquid jet

Computations for a condenser. Experimental results

International Nuclear Information System (INIS)

Walden, Jean.

1975-01-01

Computations for condensers are presented with experimental results. The computations are concerned with the steam flux at the condenser input, and inside the tube bundle. Experimental results are given for the flux inside the condenser sleeve and the flow passing through the tube bundle [fr

Charge Screening in a Charged Condensate

International Nuclear Information System (INIS)

Gabadadze, Gregory; Rosen, Rachel A.

2009-01-01

We consider a highly dense system of helium-4 nuclei and electrons in which the helium-4 nuclei have condensed. We present the condensation mechanism in the framework of low energy effective field theory and discuss the screening of electric charge in the condensate.

Influência da contaminação pela manipulação durante o procedimento restaurador sobre as propriedades mecânicas de duas resinas compostas fotopolimerizáveis

OpenAIRE

Heck, Mary A. Pereira

2006-01-01

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em Odontologia Avaliou-se, in vitro, o efeito da contaminação pela manipulação digital sobre a microdureza e resistência flexural das resinas Tetric Ceram e Filtek Z250, e identificou-se os agentes contaminantes por meio da microanálise por energia dispersiva. Os resultados mostraram que a manipulação com luva contaminada e luva contaminada limpa com álcool diminuiu a microdure...

Polariton condensates

International Nuclear Information System (INIS)

Snoke, David; Littlewood, Peter

2010-01-01

Most students of physics know about the special properties of Bose-Einstein condensates (BECs) as demonstrated in the two best-known examples: superfluid helium-4, first reported in 1938, and condensates of trapped atomic gases, first observed in 1995. (See the article by Wolfgang Ketterle in PHYSICS TODAY, December 1999, page 30.) Many also know that superfluid 3 He and superconducting metals contain BECs of fermion pairs. An underlying principle of all those condensed-matter systems, known as quantum fluids, is that an even number of fermions with half-integer spin can be combined to make a composite boson with integer spin. Such composite bosons, like all bosons, have the property that below some critical temperature--roughly the temperature at which the thermal de Broglie wavelength becomes comparable to the distance between the bosons--the total free energy is minimized by having a macroscopic number of bosons enter a single quantum state and form a macroscopic, coherent matter wave. Remarkably, the effect of interparticle repulsion is to lead to quantum mechanical exchange interactions that make that state robust, since the exchange interactions add coherently.

Comparison of condensation correlations in CATHARE for modelling isolation condenser experiment

International Nuclear Information System (INIS)

Sorjonen, J.; Kalli, H.

1996-01-01

CATHARE is a thermal-hydraulic computer code developed at the Centre d'Etudes Nucleaires de Grenoble (CENG) for nuclear power plant safety analysis. Behaviour of a new Cathare condensation correlation have been studied. The code has been applied to Isolation Condenser (IC) experiment conducted in PIPER-ONE facility. PIPER-ONE simulates a General Electric BWR-6 with volume and height scaling ratios 1/2200 and 1/1, respectively. The facility is installed at Dipartimento di Costruzioni Meccaniche e Nucleari of Pisa University. The facility was equipped with an once-through heat exchanger immersed in a pool of ambient temperature water, installed roughly 10 m above the core, in the aim to reproduce qualitatively the phenomenologies expected for Isolation Condenser in the Simplified BWR (SBWR). Experiment PO-IC-02 included two subsequent power levels with initial pressure of 5.1 MPa. The IC was active during the whole experiment except in the time period between the two different power levels. A previous calculation of above mentioned experiment by Cathare2 V1.3E showed some lacks in the condensation correlation of the code. A new correlation has been developed in Centre d'Etudes Nucleaires de Grenoble (CENG). The new calculation of the PO-IC-02 experiment by Cathare2 Vl.3U 1 with the new correlation gave results consistent with the experiment in the condensing zone of the IC. Also the overall pressure trend was reproduced with estimated heat losses to the environment. A comparison with previously obtained Relap5/Mod3. 1 results is also shown in the present document. (author) (18 refs.)

Characterization of spacecraft humidity condensate

Science.gov (United States)

Muckle, Susan; Schultz, John R.; Sauer, Richard L.

1994-01-01

When construction of Space Station Freedom reaches the Permanent Manned Capability (PMC) stage, the Water Recovery and Management Subsystem will be fully operational such that (distilled) urine, spent hygiene water, and humidity condensate will be reclaimed to provide water of potable quality. The reclamation technologies currently baselined to process these waste waters include adsorption, ion exchange, catalytic oxidation, and disinfection. To ensure that the baseline technologies will be able to effectively remove those compounds presenting a health risk to the crew, the National Research Council has recommended that additional information be gathered on specific contaminants in waste waters representative of those to be encountered on the Space Station. With the application of new analytical methods and the analysis of waste water samples more representative of the Space Station environment, advances in the identification of the specific contaminants continue to be made. Efforts by the Water and Food Analytical Laboratory at JSC were successful in enlarging the database of contaminants in humidity condensate. These efforts have not only included the chemical characterization of condensate generated during ground-based studies, but most significantly the characterization of cabin and Spacelab condensate generated during Shuttle missions. The analytical results presented in this paper will be used to show how the composition of condensate varies amongst enclosed environments and thus the importance of collecting condensate from an environment close to that of the proposed Space Station. Although advances were made in the characterization of space condensate, complete characterization, particularly of the organics, requires further development of analytical methods.

46 CFR 56.50-35 - Condensate pumps.

Science.gov (United States)

2010-10-01

... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-35 Condensate pumps. Two means shall be provided for discharging the condensate from the main condenser, one of which shall be mechanically... suction from the condenser and a discharge to the feed tank, it may be accepted as an independent...

Method for immobilizing invertase by adsorption on Dowex® anionic exchange resin Método para a imobilização da invertase por adsorção em resinas trocadoras de ânions (DOWEX

Directory of Open Access Journals (Sweden)

Ester Junko Tomotani

2006-06-01

Full Text Available This communication describes a method for adsorbing the invertase (EC.3.2.1.26 on DOWEX® anion exchange resin. Among the types of DOWEX® resins studied (1x8:50-400; 1x4:50-400 and 1x2:100-400, 1X4-200 was the most suitable, because it adsorbed the invertase molecules completely and the complex 1X4-200/invertase retained 100% of the catalytic activity. Moreover, no leakage of enzyme from the support was noted at the end of the sucrose hydrolysis.O presente trabalho descreve um método de adsorção da invertase (EC. 3.2.1.26 na resina de troca aniônica do tipo Dowex®. Entre os tipos de resinas Dowex® estudados (1x8:50-400; 1x4:50-400 e 1x2:100-400, 1x4-200 foi a mais apropriada devido à completa adsorção das moléculas de invertase e a sua retenção de atividade catalítica de 100% do complexo 1x4-200/invertase. Salienta-se ainda a ausência do desprendimento da enzima do suporte após o término da hidrólise da sacarose.

Gravitationally Driven Wicking for Enhanced Condensation Heat Transfer.

Science.gov (United States)

Preston, Daniel J; Wilke, Kyle L; Lu, Zhengmao; Cruz, Samuel S; Zhao, Yajing; Becerra, Laura L; Wang, Evelyn N

2018-04-17

Vapor condensation is routinely used as an effective means of transferring heat or separating fluids. Filmwise condensation is prevalent in typical industrial-scale systems, where the condensed fluid forms a thin liquid film due to the high surface energy associated with many industrial materials. Conversely, dropwise condensation, where the condensate forms discrete liquid droplets which grow, coalesce, and shed, results in an improvement in heat transfer performance of an order of magnitude compared to filmwise condensation. However, current state-of-the-art dropwise technology relies on functional hydrophobic coatings, for example, long chain fatty acids or polymers, which are often not robust and therefore undesirable in industrial conditions. In addition, low surface tension fluid condensates, such as hydrocarbons, pose a unique challenge because common hydrophobic condenser coatings used to shed water (with a surface tension of 73 mN/m) often do not repel fluids with lower surface tensions (condensation heat transfer using gravitationally driven flow through a porous metal wick, which takes advantage of the condensate's affinity to wet the surface and also eliminates the need for condensate-phobic coatings. The condensate-filled wick has a lower thermal resistance than the fluid film observed during filmwise condensation, resulting in an improved heat transfer coefficient of up to an order of magnitude and comparable to that observed during dropwise condensation. The improved heat transfer realized by this design presents the opportunity for significant energy savings in natural gas processing, thermal management, heating and cooling, and power generation.

Numerical investigation of convective condensation with the presence of non-condensable gases in a vertical tube

Energy Technology Data Exchange (ETDEWEB)

Fu, Wen [Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Li, Xiaowei, E-mail: lixiaowei@tsinghua.edu.cn [Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Wu, Xinxin [Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Corradini, Michael L. [Department of Engineering Physics, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, WI 53706 (United States)

2016-02-15

Highlights: • Gas mixture convective condensation in vertical tubes were simulated using FLUENT code. • The simulation results matched well with experimental data. • The detailed velocity field and species distribution were investigated. • The suction factors predicted by CFD models were compared with the classical correlations. • The effects of air and helium on steam condensation were compared. - Abstract: Steam condensation is degraded when non-condensable gases are present. Convective condensation of steam–air mixture and steam–helium mixture in vertical tubes were simulated using the CFD code FLUENT. The condensation process was modeled by defining source terms for the mass, momentum, species and energy conservation equations. Several cases with various steam mass fractions were simulated, the results matched well with the experimental data. Detailed velocity field and species distribution were investigated. The radial velocity was clearly represented, and the suction effect was modeled, which needs to be accounted for when using the heat and mass transfer analogy theory. The Nusselt and Sherwood numbers predicted by CFD models were compared with the classical correlations, and the suction effects were analyzed. The suction effect is proportional to steam mass fraction, while the suction factor is little affected by the Reynolds number. For forced convection flow in this work, the buoyant force can be neglected, so the larger diffusion coefficient of steam–helium mixture would improve the steam condensation compared to steam–air mixture. The condensation mass fluxes of steam–helium mixture and steam–air mixture are almost the same at relatively high steam inlet molar fraction (≥90%).

The application of condensate water as an additional cooling media intermittently in condenser of a split air conditioning

Science.gov (United States)

Ardita, I. N.; Subagia, I. W. A.

2018-01-01

The condensate water produced by indoor a split air conditioning is usually not utilized and thrown away into the environment. The result of measurement shows that the temperature of condensate water produced by split air conditioning is quite low, that is 19-22 °C at the rate of 16-20 mL / min and it has PH balance. Under such conditions, Air Condensate produced by split air conditioning should still be recovered as an additional cooling medium on the condenser. This research will re-investigate the use of condensate water as an intermittent additional cooling of the condenser to increase the cooling capacity and performance of the air conditioning system. This research is done by experimental method whose implementation includes; designing and manufacturing of experimental equipment, mounting measuring tools, experimental data retrieval, data processing and yield analysis. The experimental results show that the use of condensate water as an intermittent additional cooling medium on split air conditioning condenser can increase the refrigeration effect about 2%, cooling capacity about 4% and 7% of COP system. Experimental results also show a decrease in power consumption in the system compressor about 3%

Effectiveness of composite resin polymerization using light-emitting diodes (LEDs or halogen-based light-curing units Efetividade de polimerização de uma resina composta fotopolimerizada por diodos emissores de luz (LEDs ou luz halógena

Directory of Open Access Journals (Sweden)

Bianca Micali

2004-09-01

Full Text Available The clinical performance of composite resins is greatly influenced by the quality of the light-curing unit used. The aim of this study was to compare the efficiency of a commercial light-emitting diode (LED with that of a halogen-based light-curing unit by means of dye penetration of a micro hybrid composite resin. The composite resin evaluated was Filtek Z250 (3M Dental. The composite was filled into acrylic moulds that were randomly polymerized for 40 seconds by each of the light-emitting systems: light-emitting diode Ultraled (Dabi Atlante or halogen light Degulux (Degussa Hüls curing units. Immediately after polymerization, each specimen was individually immersed in 1 ml of 2% methylene blue solution at 37°C ± 2°C. After 24 hours, the specimens were rinsed under running distilled water for 1 minute and stored at 37°C ± 2°C at relative humidity for 24 hours. The composite resins were removed from the moulds and individually triturated before being immersed in new test tubes containing 1 ml of absolute alcohol for 24 hours. The solutions were filtered and centrifuged for 3 minutes at 4,000 rpm and the supernatant was used to determine absorbance in a spectrophotometer at 590 nm. To verify the differences between groups polymerized by LED or halogen light t-test was applied. No significant differences were found between composite resins light-cured by LED or halogen light-curing unit (p > 0.05. The commercially LED-based light-curing unit is as effective to polymerize hybrid composite resins as the halogen-based unit.A longevidade clínica das resinas compostas é grandemente influenciada pela qualidade do aparelho fotopolimerizador utilizado. O objetivo deste trabalho foi comparar a eficácia de um aparelho fotopolimerizador de diodos emissores de luz e a de um de luz halógena através do grau de penetração de um corante em uma resina composta micro-híbrida. A resina composta utilizada (Filtek Z250/3M Dental foi inserida em matrizes

Avaliação de monômero residual em resinas acrílicas de uso ortodôntico e protético: análise por espectroscopia Evaluation of residual monomer in autopolymerizing acrylic resins: spectroscopy analysis

Directory of Open Access Journals (Sweden)

Roberto Rocha Filho

2007-04-01

Full Text Available OBJETIVO: duas marcas comerciais de resinas acrílicas ativadas quimicamente (RAAQ, uma de uso ortodôntico (Orto Cril® e outra de uso protético (Jet®, polimerizadas em presença e ausência de pressão, foram analisadas em relação ao conteúdo de monômero (MMA residual liberado em solução, em diferentes intervalos de tempo (0,083; 0,25; 1; 1,25; 2,17; 5; 9; 14 e 21 dias. METODOLOGIA: a espectroscopia de absorção no ultravioleta foi utilizada na análise de soluções aquosas de MMA, com concentrações conhecidas, visando a determinação de uma curva de calibração. Soluções aquosas contendo corpos-de-prova, confeccionados com as citadas RAAQ, foram também submetidas à análise por espectroscopia de absorção no ultravioleta. RESULTADOS E CONCLUSÕES: os resultados foram comparados aos dados da curva de calibração, visando estabelecer a concentração de MMA residual das amostras. Eles permitiram concluir que o nível de MMA residual liberado em solução foi mais elevado durante as primeiras 24 horas, havendo uma tendência à estabilização a partir desse período e que a resina acrílica de uso ortodôntico apresentou níveis mais elevados de MMA em solução do que a de uso protético, em ambas as condições de polimerização empregadas, com presença e ausência de pressão. Além disso, a presença de pressão, durante a polimerização das duas resinas, elevou a concentração de MMA em solução, não havendo, entretanto, efeito da interação entre as marcas das resinas e a presença e ausência de pressão na concentração de MMA em solução, medida ao longo do tempo. Porém, todas as três variáveis (tempo, resina e pressão foram significantes.AIM: Two comercial brands of auto polymerizing acrylic resins (one for orthodontics use, Orto Cril®, and the other for prosthetics use, Jet® were analyzed concerning the amount of methyl methacrilate (MMA monomer dissolved in solution, processed under and not under

A Local Condensation Analysis Representing Two-phase Annular Flow in Condenser/radiator Capillary Tubes

Science.gov (United States)

Karimi, Amir

1991-01-01

NASA's effort for the thermal environmental control of the Space Station Freedom is directed towards the design, analysis, and development of an Active Thermal Control System (ATCS). A two phase, flow through condenser/radiator concept was baselined, as a part of the ATCS, for the radiation of space station thermal load into space. The proposed condenser rejects heat through direct condensation of ATCS working fluid (ammonia) in the small diameter radiator tubes. Analysis of the condensation process and design of condenser tubes are based on the available two phase flow models for the prediction of flow regimes, heat transfer, and pressure drops. The prediction formulas use the existing empirical relationships of friction factor at gas-liquid interface. An attempt is made to study the stability of interfacial waves in two phase annular flow. The formulation is presented of a stability problem in cylindrical coordinates. The contribution of fluid viscosity, surface tension, and transverse radius of curvature to the interfacial surface is included. A solution is obtained for Kelvin-Helmholtz instability problem which can be used to determine the critical and most dangerous wavelengths for interfacial waves.

An experimental study of high pressure steam condensation in a vertical tube of passive secondary condensation system

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Jae; No, Hee Cheon [KAIST, Taejon (Korea, Republic of)

1998-07-01

To investigate the physical parameters of PSCS (Passive Secondary Condensation System) which is a passive residual heat removal system of CP-1300, the high pressure condensation experiments are performed in a small scale experimental facility. The experimental parameters are the local heat flux and the transfer coefficient and the pressure drop in a condensation heat trasnfer. The film condensation heat transfer coefficients in a vertical tube are calculated from the measured wall temperature difference and compared with the analytical models. A new analytical condensation model is developed based on the annular film flow model. The present model gives marginally better results than those from the Shah model in comparison with the experimental data in the database. Also, experimental data are compared with the results of the RELAP5/MOD3.2 thermal hydraulic code. The RELAP5/MOD3.2 underpredicts the condensation heat transfer coefficients of the present experiment by 50 %.

Effect of the surface treatment of plain carbon fiber posts on the retention of the composite core: an in vitro evaluation Efeito do tratamento superficial de pinos de fibra de carbono lisos na retenção da resina de preenchimento: uma avaliação in vitro

Directory of Open Access Journals (Sweden)

Adriana Ferreira QUINTAS

2001-03-01

Full Text Available This study aims to evaluate the role of surface treatments performed on plain carbon fiber posts, in relation to serrated carbon fiber posts, in the retention of the composite core. Fifty carbon fiber posts received surface treatments in order to verify their influence on the retention of the core material. An acrylic resin mold was developed in order to precisely fit the post, leaving a machined space to accommodate a self-curing composite resin. After the surface treatment, a primer was applied on the coronal portion of all posts, which were then dried. They were fitted to the mold and received a 3 mm composite core. All specimens were thermocycled and then stored in distilled water for a week. Tension test was performed at a speed of 0.5 mm/min until there was lack of adhesion or fracture of the core. The conclusions were: a the values of retention related to aluminum oxide spray (group A, depth cutter diamond burs (group C and posts with machined coronal portion (group D were comparable to those of serrated posts (group E, although no statistically significant difference between these groups was found; b the mean values of core retention in group B (medium grit diamond burs were statistically lower than those of other groups.Foi avaliado o possível efeito de tratamentos superficiais em pinos de fibra de carbono lisos, quando comparados aos pinos serrilhados, na retenção à resina composta empregada na confecção de núcleos de preenchimento. Foram utilizados cinqüenta pinos de fibra de carbono, divididos em cinco grupos: os quatro primeiros grupos eram constituídos por pinos do tipo liso, cujas superfícies foram tratadas, e o último grupo por dez pinos do tipo serrilhado. Foram desenvolvidas matrizes de resina acrílica com um leito ajustado para conter o pino, com um alargamento na porção coronária para posterior preenchimento com resina composta. Após o tratamento superficial, todos os pinos receberam camadas de "primer", foram

Condensing boiler applications in the process industry

International Nuclear Information System (INIS)

Chen, Qun; Finney, Karen; Li, Hanning; Zhang, Xiaohui; Zhou, Jue; Sharifi, Vida; Swithenbank, Jim

2012-01-01

Major challenging issues such as climate change, energy prices and fuel security have focussed the attention of process industries on their energy efficiency and opportunities for improvement. The main objective of this research study was to investigate technologies needed to exploit the large amount of low grade heat available from a flue gas condensing system through industrial condensing boilers. The technology and application of industrial condensing boilers in various heating systems were extensively reviewed. As the condensers require site-specific engineering design, a case study was carried out to investigate the feasibility (technically and economically) of applying condensing boilers in a large scale district heating system (40 MW). The study showed that by recovering the latent heat of water vapour in the flue gas through condensing boilers, the whole heating system could achieve significantly higher efficiency levels than conventional boilers. In addition to waste heat recovery, condensing boilers can also be optimised for emission abatement, especially for particle removal. Two technical barriers for the condensing boiler application are corrosion and return water temperatures. Highly corrosion-resistant material is required for condensing boiler manufacture. The thermal design of a 'case study' single pass shell-and-tube condensing heat exchanger/condenser showed that a considerable amount of thermal resistance was on the shell-side. Based on the case study calculations, approximately 4900 m 2 of total heat transfer area was required, if stainless steel was used as a construction material. If the heat transfer area was made of carbon steel, then polypropylene could be used as the corrosion-resistant coating material outside the tubes. The addition of polypropylene coating increased the tube wall thermal resistance, hence the required heat transfer area was approximately 5800 m 2 . Net Present Value (NPV) calculations showed that the choice of a carbon

Design analysis of a Helium re-condenser

Science.gov (United States)

Muley, P. K.; Bapat, S. L.; Atrey, M. D.

2017-02-01

Modern helium cryostats deploy a cryocooler with a re-condenser at its II stage for in-situ re-condensation of boil-off vapor. The present work is a vital step in the ongoing research work of design of cryocooler based 100 litre helium cryostat with in-situ re-condensation. The cryostat incorporates a two stage Gifford McMahon cryocooler having specified refrigerating capacity of 40 W at 43 K for I stage and 1 W at 4.2 K for II stage. Although design of cryostat ensures thermal load for cryocooler below its specified refrigerating capacity at the second stage, successful in-situ re-condensation depends on proper design of re-condenser which forms the objective of this work. The present work proposes design of helium re-condenser with straight rectangular fins. Fins are analyzed for optimization of thermal performance parameters such as condensation heat transfer coefficient, surface area for heat transfer, re-condensing capacity, efficiency and effectiveness. The present work provides design of re-condenser with 19 integral fins each of 10 mm height and 1.5 mm thickness with a gap of 1.5 mm between two fins, keeping in mind the manufacturing feasibility, having efficiency of 80.96 % and effectiveness of 10.34.

Vapor condensation device

International Nuclear Information System (INIS)

Sakurai, Manabu; Hirayama, Fumio; Kurosawa, Setsumi; Yoshikawa, Jun; Hosaka, Seiichi.

1992-01-01

The present invention enables to separate and remove 14 C as CO 3 - ions without condensation in a vapor condensation can of a nuclear facility. That is, the vapor condensation device of the nuclear facility comprises (1) a spray pipe for spraying an acidic aqueous solution to the evaporation surface of an evaporation section, (2) a spray pump for sending the acidic aqueous solution to the spray pipe, (3) a tank for storing the acidic aqueous solution, (4) a pH sensor for detecting pH of the evaporation section, (5) a pH control section for controlling the spray pump, depending on the result of the detection of the pH sensor. With such a constitution, the pH of liquid wastes on the vaporization surface is controlled to 7 by spraying an aqueous solution of dilute sulfuric acid to the evaporation surface, thereby enabling to increase the transfer rate of 14 C to condensates to 60 to 70%. If 14 C is separated and removed as a CO 2 gas from the evaporation surface, the pH of the liquid wastes returns to the alkaline range of 9 to 10 and the liquid wastes are returned to a heating section. The amount of spraying the aqueous solution of dilute sulfuric acid can be controlled till the pH is reduced to 5. (I.S.)

Fluegas condensation of domestic fuels. Kotimaisten polttoaineiden savukaasulauhdutus

Energy Technology Data Exchange (ETDEWEB)

Kankkunen, A; Fagerholm, N E

1988-01-01

The suitability of domestic fuel for condensation heat recovery was studied. With the developed computer program, enthalpies of flue gas as function of temperature were computed and also the theoretical advandages aquired by condensation were compared with different fuels. The maximal advantages of condensation were 39 % with wooden chips and 31 % with peat. The domestic fuels were found to be useful for condensation heat recovery because of the high water content and the high dewpoint of flu egas. Condensation was found to have a purifying effect on flue gases. It was found experimentaly that 30 % the sulfur of the peat dissolved to the condensed liquid. The composition of condensed liquid of peat- and wooden chip flue gases was studied to find out the corrosion and enviromental effects. The risk of corrosion to metallic heat exhanger was concluded from the compositio of peat condensat. Chip condensate was found to be almost neutral. Normally the condensate liquids were fit for sewering without aftertreatment. Heat transfer coefficient from flue gases to the wall of the condenser was measured to be 150-170 W/Km{sup 2}. Heat transfer coefficients were three times higher compared to condensing heat transfer.

Capillary-Condenser-Pumped Heat-Transfer Loop

Science.gov (United States)

Silverstein, Calvin C.

1989-01-01

Heat being transferred supplies operating power. Capillary-condenser-pumped heat-transfer loop similar to heat pipe and to capillary-evaporator-pumped heat-transfer loop in that heat-transfer fluid pumped by evaporation and condensation of fluid at heat source and sink, respectively. Capillary condenser pump combined with capillary evaporator pump to form heat exchanger circulating heat-transfer fluids in both loops. Transport of heat more nearly isothermal. Thermal stress in loop reduced, and less external surface area needed in condenser section for rejection of heat to heat sink.

Emergency condensator for BWR type reactor

International Nuclear Information System (INIS)

Ubakai, Yoichi; Narumi, Yuichi; Sakata, Yuji.

1992-01-01

An emergency condensator is constituted with heat transfer pipes, a steam chamber, an upper pipe plate, a lower pipe plate and a condensate chamber. The upper pipe plate is secured by supports, and a steam pipe is connected to the upper pipe plate. A condensate pipeline and a incondensible gas vent pipe are disposed to the condensate chamber. Taking thermal expansion of the steam pipes and thermal expansion of the heat transfer pipes into consideration, the heat transfer pipe is made as an L-shaped pipe having a vertical portion and a horizontal portion so as to absorb each of the thermal expansion smoothly. The L-shaped heat transfer pipes are constituted as a bundle of pipes having the end portions thereof secured to the upper pipe plate and the lower pipe plate. The emergency condensator is disposed in a emergency condensator pool chamber. Cooling water in contact with the outer side of the L-shaped heat transfer pipes is the pool water in the pool chamber, and the condensator chamber is disposed in concrete walls of the pool chamber. With such a constitution, stress due to thermal expansion of the heat transfer pipes is mitigated, and heat transfer performance, earth quake resistance and maintenancability are improved. (I.N.)

Experimental investigation of non-condensable gases effect on operation of VVER steam generator in condensation mode

International Nuclear Information System (INIS)

Efanov, A. D.; Kalyakin, S. G.; Morozov, A. V.; Remizov, O. V.; Tsyganok, A. A.; Generalov, V. N.; Berkovich, V. M.; Taranov, G. S.

2008-01-01

To provide the safety in new Russian NPP designs, protection passive systems which don't depend upon human errors are widely used. In terms of safety, the design of NPP of new generation (NPP-2006) falls into the class of advanced NPPs. In the event of an beyond design basis accident with the rupture of the reactor primary circuit and accompanied by the loss of ac sources, the use of passive safety systems are provided for necessary core cooling. Among these is passive heat removal system (PHRS). In the case of leakage in the primary circuit this system ensures the transition of steam generators (SG) to operation in the mode of condensation of the primary circuit steam coming to SG piping from the reactor. As a result, the condensate from steam generators arrives at the core providing its additional cooling. The SG condensation capacity can be adversely affected by the presence of non-condensable gases in the primary circuit of the reactor. Their main sources are nitrogen arriving at the circuit, as hydro accumulators actuate, products of radiolysis of water and air drawn in from the containment through the pipeline rupture. The accumulation of non-condensable gases in SG piping can result in degradation of its condensation capacity to the extent that condensation completely terminates. In this case, the core cooling conditions may be impaired. To experimental investigation of the condensation mode of operation of WER steam generator, a large scale HA2M-SG test rig was constructed at the SSC RF IPPE. The test rig incorporates: buffer tank, equipped by steam supply system; SG model with volumetric-power scale is 1:46; PHRS heat exchanger imitator, cooling by process water. The rig main equipment connected by pipelines and equipped by valves. The elevations of the main equipment correspond to those of reactor project. The rig maximum operating parameters: steam pressure - 1.6 MPa, temperature - 200 Celsius degrees. Experiments at the HA2M-SG test rig have been

Titanium application to power plant condensers

International Nuclear Information System (INIS)

Itoh, H.

1987-01-01

Recently, the growth of operating performance and construction plan of titanium-tubed condensers in thermal and unclear power plants has been very impressive. High-quality, thinner welded titanium tubes used for cooling tubes, matching design specifications of condensers, have been stably supplied through mass production. It now can be said that various technical problems for titanium-tubed condensers have been solved, but data on operating performance in large-scale commercial plants are still scarce, and site-by-site information needs be exchanged more frequently and on a larger scale. Projects to replace existing condenser cooling tubes with those of corrosion-resistant titanium have been actively furthered, with the only remaining barrier to full employment being cost effectiveness. It is hoped that condenser and tube manufacturers will conduct more joint value analyses

Bose Condensate in He II

International Nuclear Information System (INIS)

Svensson, E.C.

1984-01-01

The Condensate Saga, now halfway through its fifth decade, is reviewed. The recent neutron-scattering work which has at last convincingly established that there is indeed a Bose Condensate in He II is described

Estudio de eliminación de arsénico con resinas de intercambio iónico en agua potable de Zimapán, Estado de Hidalgo, México

Directory of Open Access Journals (Sweden)

Pérez-Moreno, F.

2006-10-01

Full Text Available Anionic exchange resins were research with respect its capacity for removal arsenic content in water. Water of well V from Zimapán Hidalgo Mexico was used to make this research, because this water have a mean concentration of 480 ± 11 μg·L^-1 of arsenic and it is
available as drinking water. The exchange resins employed were two strong anionic, one macroreticular (IRA-900 and other gel type (IRA-400, as soon as one third anionic weak macroreticular type (IRA-96. The experiments carried with this resins showing that IRA-900 has highest efficient in the process of arsenic removal from drinking water, because, it showed a treatment capacity of 700 V_agua·V_res^-1; while that capacities of IRA-400 e IRA-96 resins were 320 and 52 V_agua·V_res^-1 respectively. The mean concentration of arsenic residue in the treatise water was 24 μg·l^-1 and it is within the maximum level permissible by Mexican official norm for drinking water.

Se investigaron resinas de intercambio aniónico con respecto a su capacidad para la eliminación de arsénico contenido en agua. Se utilizó agua del pozo V de Zimapán, Hidalgo, México, cuya concentración promedio es de 480 ± 11 μg·l^-1 de arsénico y es utilizada para consumo humano. Se emplearon dos reinas aniónicas fuertes; una, de tipo macro reticular (IRA-900 y la otra de tipo gel (IRA-400, así como una tercera, aniónica débil, de tipo macro reticular (IRA-96. Los experimentos realizados con estas resinas muestran que la IRA-900 es la que mostró la más alta eficiencia en la eliminación de arsénico del agua potable, debido a que presentó una capacidad de tratamiento de 700 V_agua·V_res^-1, mientras que las capacidades de las resinas IRA-400 e IRA-96 fueron de 320 y 52 V_agua·V_res^-1, respectivamente. La concentración promedio de ars

Modelling of film condensation in presence of non condensable gases

International Nuclear Information System (INIS)

Genevieve Geffraye; Dominique Bestion; Vladimir Kalitvianski

2005-01-01

Full text of publication follows: This paper presents recent developments in the modelling of the condensation due to heat removal from a wall with a possible presence of hydrogen, nitrogen, or air. This work is mainly concerned with nuclear reactor safety with particular reference to situations related to new reactor design, cold shutdown state and severe accident analysis. Film condensation of steam in presence of nitrogen and helium in a tube has been investigated in the COTURNE experiment in a rather large range of parameters, pressure (from 0.1 to 7 Mpa), heat flux (0.1 to 6 W/cm 2 ), mass fraction of noncondensable gas (0 to 1) and also in presence of superheated steam. The experiment represents a Steam Generator tube of a Pressurised Water Reactor and can simulate both co-current or countercurrent flow of steam and water.The models are implemented in the CATHARE code used for nuclear reactor thermal-hydraulics. The code uses two mass balance equations for liquid and gas, two momentum balance equations for liquid and gas and two energy balance equations for liquid and gas. Additional mass transport equations can be added for each non condensable gas. Heat transfers from wall to liquid film, from liquid to interface and gas to interface are modelled. The liquid film heat transfer coefficient is first investigated in pure saturated steam conditions in the pressure range from 0.1 to 7 Mpa. The CATHARE film condensation model in pure steam conditions is derived from Chen's correlation. Chen proposes a general correlation for the film condensation, covering the wavy-laminar and the turbulent film regimes and taking into account the interfacial friction effect. A large data base of laminar film regime was used including COTURNE data other available data found in the literature. The analysis of these data base suggests an influence of the liquid Reynolds number, according to the Nusselt theory, and also of the Eoetvoes number, with surface tension effects. A

QCD condensates in ADS/QCD

DEFF Research Database (Denmark)

Bechi, Jacopo

2009-01-01

This paper focuses on some issues about condensates and renormalization in AdS/QCD models. In particular we consider the consistency of the AdS/QCD approach for scale dependent quantities as the chiral condensate questioned in some recent papers and the 4D meaning of the 5D cosmological constant...... in a model in which the QCD is dual to a 5D gravity theory. We will be able to give some arguments that the cosmological constant is related to the QCD gluon condensate....

Bose condensation in (random traps

Directory of Open Access Journals (Sweden)

V.A. Zagrebnov

2009-01-01

Full Text Available We study a non-interacting (perfect Bose-gas in random external potentials (traps. It is shown that a generalized Bose-Einstein condensation in the random eigenstates manifests if and only if the same occurs in the one-particle kinetic-energy eigenstates, which corresponds to the generalized condensation of the free Bose-gas. Moreover, we prove that the amounts of both condensate densities are equal. This statement is relevant for justification of the Bogoliubov approximation} in the theory of disordered boson systems.

Condensed matter physics

CERN Document Server

Isihara, A

2007-01-01

More than a graduate text and advanced research guide on condensed matter physics, this volume is useful to plasma physicists and polymer chemists, and their students. It emphasizes applications of statistical mechanics to a variety of systems in condensed matter physics rather than theoretical derivations of the principles of statistical mechanics and techniques. Isihara addresses a dozen different subjects in separate chapters, each designed to be directly accessible and used independently of previous chapters. Topics include simple liquids, electron systems and correlations, two-dimensional

Utilização de uma resina preparada pelo método da solução líquida de citratos como ligante durante a preparação de filtros cerâmicos à base de alumina Utilization of a resin, prepared by the citrate liquid solution method, as binder during the manufacturing of alumina-based ceramic filters

OpenAIRE

D. Gouvêa; W. A. Savaglia Neto; J. D. T. Capocchi

1999-01-01

Este trabalho propõe a preparação de filtros cerâmicos macroporosos pela técnica da impregnação de espumas de poliuretano e utilização de uma resina preparada pelo método Pechini contendo íons alumínio e manganês como ligante. Nas temperaturas inferiores à de combustão da resina a parte orgânica age com ligante. Após a decomposição térmica, o produto da combustão, ou seja, alumina contendo íons Mn, passa a ser um ligante inorgânico mas apresentando composição química semelhante à do filtro. O...

Experimental hydraulic analysis in conduction tunnels at the trunk section working as a channel considering compound roughness; Analisis hidraulico experimental en tuneles de conduccion en seccion baul trabajando como canal, considerando rugosidades compuestas

Energy Technology Data Exchange (ETDEWEB)

Marengo-Mogollon, Humberto; Cortes-Cortes, Carlos [Comision Federal de Electricidad (Mexico); Arreguin-Cortes, Felipe I [Comision Nacional del Agua (Mexico)

2008-01-15

This paper presents the roughness coefficients of a conduction tunnel at the trunk section working as a channel obtained experimentally using a hydraulic model of the diversion tunnel of the Hydroelectric Project called El Cajon (Mexico). A comparative analysis between experimental and theoretical coefficients obtained in the literature is shown. [Spanish] Se presentan los coeficientes de rugosidad compuesta de un tunel de conduccion en seccion baul trabajando como canal obtenidos en forma experimental en un modelo hidraulico del tunel de desvio del Proyecto Hidroelectrico El Cajon (Mexico). Se muestra un analisis comparativo entre los coeficientes experimentales y los teoricos obtenidos en la literatura.

Dual approaches for defects condensation

Energy Technology Data Exchange (ETDEWEB)

Rougemont, Romulo; Grigorio, Leonardo de Souza; Wotzasek, Clovis [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Guimaraes, Marcelo Santos [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

2009-07-01

Full text. Due to the fact that the QCD running coupling constant becomes larger as we go into the low energy (or large distance) limit of the theory, a perturbative treatment of its infrared (IR) region is impossible. In particular, a formal mathematical demonstration of color confinement and a complete physical understanding of the exact mechanism that confines quarks and gluons are two missing points in our current knowledge of the IR-QCD. It was known that due to the Meissner effect of expulsion of magnetic fields in a electric condensate that usual superconductors should confine magnetic monopoles. That point led to the conjecture that the QCD vacuum could be a condensate of chromomagnetic monopoles, a dual superconductor (DSC). Such a chromomagnetic condensate should be responsible for the dual Meissner effect which is expected to lead to the confinement of color charges immersed in this medium. In dual superconductor models of color confinement, magnetic monopoles appear as topological defects in points of the space where the abelian projection becomes singular. Also, condensation of other kinds of defects such as vortices in superfluids and line-like defects in solids are responsible for a great variety of phase transitions, which once more proves the relevance of the subject. In the present work we review two methods that allow us to approach the condensation of defects: the Kleinert Mechanism (KM) and the Julia-Toulouse Mechanism (JTM). We show that in the limit where the vortex gauge field goes to zero, which we identify as the signature of the condensation of defects in the dual picture, these are two equivalent dual prescriptions for obtaining an effective theory for a phase where defects are condensed, starting from the fundamental theory defined in the normal phase where defects are diluted. (author)

Development of balanced downflow type surface condensers, (2)

International Nuclear Information System (INIS)

Tomida, Akira; Oshima, Yoshikuni; Okochi, Isao; Izumi, Kenkichi.

1976-01-01

As the size of the condensers for power generation plants grew large, the new balanced downflow type condenser was developed and completed on the basis of the experiment on steam flow according to the two-dimensional flow model, the analysis of the performance in a tube nest with a computer, and the studies on the effect of outside liquid film and the reheating deaeration of condensate. When the balanced downflow type condensers were adopted for actual plants, the construction, strength and production method were examined, and the reliability of the new condenser was confirmed by the thermal characteristic experiment with the model similar to the actual machine. The condenser comprises a condenser body, supporting plates, cooling tubes, tube plates, water chambers, and reinforcements, and the cooling tubes are arranged so as to exchange heat effectively. The arrangement of tubes is divided into three regions, namely radiation portion, densely arranged portion, and air cooling portion. In the balanced downflow type condensers, the dilution by utilizing condensate is provided against ammonia attack. The apparatuses for the thermal characteristic experiment and the experimental results, and the results of the performance test on the actual balanced downflow type condenser are reported. (Kako, I.)

A Study on Condensation Heat Transfer at the Exterior Surface of S.A.M. Coated Titanium Tube Using in Steam Condensers

Energy Technology Data Exchange (ETDEWEB)

Im, Sung-Gu; Lee, Sang-Hyup; Ji, Dae-Yun; Park, Hyun-Gyu; Lee, Kwon-Yeong [Handong Global University, Pohang (Korea, Republic of)

2016-10-15

Condensation occurs when the temperature of a steam is reduced below its saturation temperature. There exist two forms of condensation on cooling surface: dropwise, and film condensations. Usually, dropwise condensation has a better heat transfer performance than film condensation, but it has limit of short period. Ma et al. executed heat transfer experiment in dropwise condensation with non-condensable gas, and studied how the amount of air and pressure difference affect condensation heat transfer coefficient. The more non-condensable gas exist, the condensation heat transfer coefficient is decreased. As a result, surface modified brass tube and stainless tube showed higher condensation heat transfer coefficient as much as 1.3 and 1.4 times comparing with their bare tubes in 70 kPa vacuum condition respectively. Most of power plants use sea water as coolant, so the surface of metal tubes could be corroded by the coolant. We had researched an experimental study related to condensation heat transfer on surface modified titanium tube. Our experimental facility was designed to show how two kinds of tube's heat transfer performances are different in a same condition. We changed the range of saturation pressure and coolant flow rate to observe tube's performance change. When saturation pressure and coolant flow rate increase, overall heat transfer coefficients were increased. When residue of non-condensable gases was decreased, the overall heat transfer coefficients were increased. S.A.M. coated tube's overall heat transfer coefficients were lower than those of bare tube, because the droplets didn't have a tendency of frequently falling down.

Fermion condensation and gapped domain walls in topological orders

Energy Technology Data Exchange (ETDEWEB)

Wan, Yidun [Department of Physics and Center for Field Theory and Particle Physics, Fudan University,Shanghai 200433 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University,Nanjing 210093 (China); Perimeter Institute for Theoretical Physics,Waterloo N2L 2Y5, Ontario (Canada); Wang, Chenjie [Perimeter Institute for Theoretical Physics,Waterloo N2L 2Y5, Ontario (Canada)

2017-03-31

We study fermion condensation in bosonic topological orders in two spatial dimensions. Fermion condensation may be realized as gapped domain walls between bosonic and fermionic topological orders, which may be thought of as real-space phase transitions from bosonic to fermionic topological orders. This picture generalizes the previous idea of understanding boson condensation as gapped domain walls between bosonic topological orders. While simple-current fermion condensation was considered before, we systematically study general fermion condensation and show that it obeys a Hierarchy Principle: a general fermion condensation can always be decomposed into a boson condensation followed by a minimal fermion condensation. The latter involves only a single self-fermion that is its own anti-particle and that has unit quantum dimension. We develop the rules of minimal fermion condensation, which together with the known rules of boson condensation, provides a full set of rules for general fermion condensation.

Models of coherent exciton condensation

International Nuclear Information System (INIS)

Littlewood, P B; Eastham, P R; Keeling, J M J; Marchetti, F M; Simons, B D; Szymanska, M H

2004-01-01

That excitons in solids might condense into a phase-coherent ground state was proposed about 40 years ago, and has been attracting experimental and theoretical attention ever since. Although experimental confirmation has been hard to come by, the concepts released by this phenomenon have been widely influential. This tutorial review discusses general aspects of the theory of exciton and polariton condensates, focusing on the reasons for coherence in the ground state wavefunction, the BCS to Bose crossover(s) for excitons and for polaritons, and the relationship of the coherent condensates to standard lasers

Models of coherent exciton condensation

Energy Technology Data Exchange (ETDEWEB)

Littlewood, P B [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Eastham, P R [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Keeling, J M J [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Marchetti, F M [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Simons, B D [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Szymanska, M H [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom)

2004-09-08

That excitons in solids might condense into a phase-coherent ground state was proposed about 40 years ago, and has been attracting experimental and theoretical attention ever since. Although experimental confirmation has been hard to come by, the concepts released by this phenomenon have been widely influential. This tutorial review discusses general aspects of the theory of exciton and polariton condensates, focusing on the reasons for coherence in the ground state wavefunction, the BCS to Bose crossover(s) for excitons and for polaritons, and the relationship of the coherent condensates to standard lasers.

ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: NEW CONDENSATOR, INC.--THE CONDENSATOR DIESEL ENGINE RETROFIT CRANKCASE VENTILATION SYSTEM

Science.gov (United States)

EPA's Environmental Technology Verification Program has tested New Condensator Inc.'s Condensator Diesel Engine Retrofit Crankcase Ventilation System. Brake specific fuel consumption (BSFC), the ratio of engine fuel consumption to the engine power output, was evaluated for engine...

Quality factors to consider in condensate selection

Energy Technology Data Exchange (ETDEWEB)

Lywood, B. [Crude Quality Inc., Edmonton, AB (Canada)

2009-07-01

Many factors must be considered when assessing the feasibility of using condensates as a diluent for bitumen or heavy crude production blending. In addition to commercial issues, the effect of condensate quality is a key consideration. In general, condensate quality refers to density and viscosity. However, valuation decisions could be enhanced through the expansion of quality definitions and understanding. This presentation focused on the parameters that are important in choosing a diluent grade product. It also reviewed pipeline and industry specifications and provided additional information regarding general properties for bitumen and condensate compatibility; sampling and quality testing needs; and existing sources of information regarding condensate quality. tabs., figs.

Advances in modelling of condensation phenomena

Energy Technology Data Exchange (ETDEWEB)

Liu, W.S.; Zaltsgendler, E. [Ontario Hydro Nuclear, Toronto (Canada); Hanna, B. [Atomic Energy of Canada Limited, Pinawa, Manitoba (Canada)

1997-07-01

The physical parameters in the modelling of condensation phenomena in the CANDU reactor system codes are discussed. The experimental programs used for thermal-hydraulic code validation in the Canadian nuclear industry are briefly described. The modelling of vapour generation and in particular condensation plays a key role in modelling of postulated reactor transients. The condensation models adopted in the current state-of-the-art two-fluid CANDU reactor thermal-hydraulic system codes (CATHENA and TUF) are described. As examples of the modelling challenges faced, the simulation of a cold water injection experiment by CATHENA and the simulation of a condensation induced water hammer experiment by TUF are described.

Advances in modelling of condensation phenomena

International Nuclear Information System (INIS)

Liu, W.S.; Zaltsgendler, E.; Hanna, B.

1997-01-01

The physical parameters in the modelling of condensation phenomena in the CANDU reactor system codes are discussed. The experimental programs used for thermal-hydraulic code validation in the Canadian nuclear industry are briefly described. The modelling of vapour generation and in particular condensation plays a key role in modelling of postulated reactor transients. The condensation models adopted in the current state-of-the-art two-fluid CANDU reactor thermal-hydraulic system codes (CATHENA and TUF) are described. As examples of the modelling challenges faced, the simulation of a cold water injection experiment by CATHENA and the simulation of a condensation induced water hammer experiment by TUF are described

Condensation on Superhydrophobic Copper Oxide Nanostructures

OpenAIRE

Enright, Ryan; Miljkovic, Nenad; Dou, Nicholas; Nam, Youngsuk; Wang, Evelyn N.

2013-01-01

Condensation is an important process in both emerging and traditional power generation and water desalination technologies. Superhydrophobic nanostructures promise enhanced condensation heat transfer by reducing the characteristic size of departing droplets via a surface-tension-driven mechanism [1]. In this work, we investigated a scalable synthesis technique to produce oxide nanostructures on copper surfaces capable of sustaining superhydrophobic condensation and characterized the growth an...

Condensation heat transfer coefficient of air-cooled condensing heat exchanger of emergency cooldown tank in long-term passive cooling system

International Nuclear Information System (INIS)

Huh, Seon Jeong; Lee, Hee Joon; Moon, Joo Hyung; Bae, Youngmin; Kim, Young In

2017-01-01

For the design purpose of air-cooled condensing heat exchanger of emergency cooldown tank, average condensation heat transfer coefficient inside a circular tube was reduced by a thermal sizing program using the experimental data of Kim et al. It was compared to the existing condensation heat transfer correlations. Moreover, a sensitivity analysis of both inside condensation and outside air natural convection correlations was performed. Although condensation heat transfer did not play a great role to design over 10 3 W/m 2 /K, the improved Shah's correlation gives the best prediction for the design. Consequently, air natural convection coefficient significantly affects the design of air-cooled condensing heat exchanger. (author)

Molecular equilibrium with condensation

International Nuclear Information System (INIS)

Sharp, C.M.; Huebner, W.F.

1990-01-01

Minimization of the Gibbs energy of formation for species of chemical elements and compounds in their gas and condensed phases determines their relative abundances in a mixture in chemical equilibrium. The procedure is more general and more powerful than previous abundance determinations in multiphase astrophysical mixtures. Some results for astrophysical equations of state are presented, and the effects of condensation on opacity are briefly indicated. 18 refs

Continuous condensation in nanogrooves

Science.gov (United States)

Malijevský, Alexandr

2018-05-01

We consider condensation in a capillary groove of width L and depth D , formed by walls that are completely wet (contact angle θ =0 ), which is in a contact with a gas reservoir of the chemical potential μ . On a mesoscopic level, the condensation process can be described in terms of the midpoint height ℓ of a meniscus formed at the liquid-gas interface. For macroscopically deep grooves (D →∞ ), and in the presence of long-range (dispersion) forces, the condensation corresponds to a second-order phase transition, such that ℓ ˜(μcc-μ ) -1 /4 as μ →μcc - where μc c is the chemical potential pertinent to capillary condensation in a slit pore of width L . For finite values of D , the transition becomes rounded and the groove becomes filled with liquid at a chemical potential higher than μc c with a difference of the order of D-3. For sufficiently deep grooves, the meniscus growth initially follows the power law ℓ ˜(μcc-μ ) -1 /4 , but this behavior eventually crosses over to ℓ ˜D -(μ-μc c) -1 /3 above μc c, with a gap between the two regimes shown to be δ ¯μ ˜D-3 . Right at μ =μc c , when the groove is only partially filled with liquid, the height of the meniscus scales as ℓ*˜(D3L) 1 /4 . Moreover, the chemical potential (or pressure) at which the groove is half-filled with liquid exhibits a nonmonotonic dependence on D with a maximum at D ≈3 L /2 and coincides with μc c when L ≈D . Finally, we show that condensation in finite grooves can be mapped on the condensation in capillary slits formed by two asymmetric (competing) walls a distance D apart with potential strengths depending on L . All these predictions, based on mesoscopic arguments, are confirmed by fully microscopic Rosenfeld's density functional theory with a reasonable agreement down to surprisingly small values of both L and D .

Influência do tipo de ponteira condutora de luz na microdureza de uma resina composta Influence of the different light-curing TIPS in the microhardness of a composite resin

Directory of Open Access Journals (Sweden)

Máx Dobrovolski

2010-01-01

Full Text Available O objetivo desta pesquisa foi avaliar a influência do tipo de ponteira condutora de luz na microdureza de uma resina composta micro-híbrida. Foram confeccionados 14 corpos de prova da resina composta Opallis (FGM com dimensões: 5 x 2 mm, divididos em dois grupos de acordo com a ponteira condutora de luz do aparelho fotoativador de lâmpada halógena Optilight Plus - GNATUS/300 mW.cm-2. GI - ponteira condutora de luz de fibra óptica; GII - ponteira condutora de luz de polímero. Após 24 horas, as medidas de microdureza foram efetuadas com um microdurômetro HMV 2000 (Shimadzu Japão. Cinco penetrações foram efetuadas em cada superfície (topo e base totalizando 10 penetrações para cada corpo de prova. A análise estatística dos resultados realizada por meio do teste de ANOVA não apresentou diferenças significativas entre os tipos de ponta condutora de luz nas superfícies avaliadas. A análise estatística demonstrou diferença significativa nos valores médios de microdureza superficial entre as superfícies de topo e de base, para ambas as ponteiras. Com base nos resultados obtidos, foi possível concluir que as ponteiras de luz não interferem na microdureza da resina composta, e que ambas apresentaram diferenças estatisticamente significativas nos valores de microdureza das superfícies topo e base.The aim of this study is to evaluate the influence of the light-curing tips on the microhardness of a micro-hybrid composite resin. Fourteen samples of Opallis (FGM composite resin with 5 x 2 mm were prepared. The specimens were divided into two groups according to the light-curing tips from a halogen light curing unit (Optilight Plus -GNATUS/300 mW.cm-2: GI - optical fiber light-curing; GII - polymer light-curing. After 24 hours, the microhardness measurements were determined using the HMV 2000 (Shimadzu Japan. Five measurements were made on each surface (top and bottom totalizing 10 indentations for each sample. Statistical analysis

Direct contact condensation in packed beds

Energy Technology Data Exchange (ETDEWEB)

Li, Yi; Klausner, James F.; Mei, Renwei; Knight, Jessica [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)

2006-12-15

A diffusion driven desalination process was recently described where a very effective direct contact condenser with a packed bed is used to condense water vapor out of an air/vapor mixture. A laboratory scale direct contact condenser has been fabricated as a twin tower structure with two stages, co-current and countercurrent. Experiments have been operated in each stage with respective saturated air inlet temperatures of 36, 40 and 43{sup o}C. The temperature and humidity data have been collected at the inlet and exit of the packed bed for different water to air mass flow ratios that vary between 0 and 2.5. A one-dimensional model based on conservation principles has been developed, which predicts the variation of temperature, humidity, and condensation rate through the condenser stages. Agreement between the model and experiments is very good. It is observed that the countercurrent flow stage condensation effectiveness is significantly higher than that for the co-current stage. The condensation heat and mass transfer rates were found to decrease when water blockages occur within the packed bed. Using high-speed digital cinematography, it was observed that this problem can occur at any operating condition, and is dependent on the packing surface wetting characteristics. This observation is used to explain the requirement for two different empirical constants, depending on packing diameter, suggested by Onda for the air side mass transfer coefficient correlation. (author)

Organic condensation: a vital link connecting aerosol formation to cloud condensation nuclei (CCN) concentrations

Science.gov (United States)

Riipinen, I.; Pierce, J. R.; Yli-Juuti, T.; Nieminen, T.; Häkkinen, S.; Ehn, M.; Junninen, H.; Lehtipalo, K.; Petäjä, T.; Slowik, J.; Chang, R.; Shantz, N. C.; Abbatt, J.; Leaitch, W. R.; Kerminen, V.-M.; Worsnop, D. R.; Pandis, S. N.; Donahue, N. M.; Kulmala, M.

2011-04-01

Atmospheric aerosol particles influence global climate as well as impair air quality through their effects on atmospheric visibility and human health. Ultrafine (<100 nm) particles often dominate aerosol numbers, and nucleation of atmospheric vapors is an important source of these particles. To have climatic relevance, however, the freshly nucleated particles need to grow in size. We combine observations from two continental sites (Egbert, Canada and Hyytiälä, Finland) to show that condensation of organic vapors is a crucial factor governing the lifetimes and climatic importance of the smallest atmospheric particles. We model the observed ultrafine aerosol growth with a simplified scheme approximating the condensing species as a mixture of effectively non-volatile and semi-volatile species, demonstrate that state-of-the-art organic gas-particle partitioning models fail to reproduce the observations, and propose a modeling approach that is consistent with the measurements. We find that roughly half of the mass of the condensing mass needs to be distributed proportional to the aerosol surface area (thus implying that the condensation is governed by gas-phase concentration rather than the equilibrium vapour pressure) to explain the observed aerosol growth. We demonstrate the large sensitivity of predicted number concentrations of cloud condensation nuclei (CCN) to these interactions between organic vapors and the smallest atmospheric nanoparticles - highlighting the need for representing this process in global climate models.

Scrutinizing the pion condensed phase

Energy Technology Data Exchange (ETDEWEB)

Carignano, Stefano; Mammarella, Andrea; Mannarelli, Massimo [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Lepori, Luca [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito-L' Aquila (Italy); Pagliaroli, Giulia [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gran Sasso Science Institute, L' Aquila (Italy)

2017-02-15

When the isospin chemical potential exceeds the pion mass, charged pions condense in the zero-momentum state forming a superfluid. Chiral perturbation theory provides a very powerful tool for studying this phase. However, the formalism that is usually employed in this context does not clarify various aspects of the condensation mechanism and makes the identification of the soft modes problematic. We re-examine the pion condensed phase using different approaches within the chiral perturbation theory framework. As a first step, we perform a low-density expansion of the chiral Lagrangian valid close to the onset of the Bose-Einstein condensation. We obtain an effective theory that can be mapped to a Gross-Pitaevskii Lagrangian in which, remarkably, all the coefficients depend on the isospin chemical potential. The low-density expansion becomes unreliable deep in the pion condensed phase. For this reason, we develop an alternative field expansion deriving a low-energy Lagrangian analog to that of quantum magnets. By integrating out the ''radial'' fluctuations we obtain a soft Lagrangian in terms of the Nambu-Goldstone bosons arising from the breaking of the pion number symmetry. Finally, we test the robustness of the second-order transition between the normal and the pion condensed phase when next-to-leading-order chiral corrections are included. We determine the range of parameters for turning the second-order phase transition into a first-order one, finding that the currently accepted values of these corrections are unlikely to change the order of the phase transition. (orig.)

Demonstration of Nautilus Centripetal Capillary Condenser Technology

Science.gov (United States)

Wheeler, RIchard; Tang, Linh; Wambolt, Spencer; Golliher, Eric; Agui, Juan

2016-01-01

This paper describes the results of a proof of concept effort for development of a Nautilus Centripetal Capillary Condenser (NCCC or NC3) used for microgravity compatible water recovery from moist air with integral passive phase separation. Removal of liquid condensate from the air stream exiting a condenser is readily performed here on Earth. In order to perform this function in space however, without gravity or mechanical action, other tactics including utilization of inertial, drag and capillary forces are required. Within the NC3, liquid water forms via condensation on cold condenser surfaces as humid air passes along multiple spiral channels, each in its own plane, all together forming a stacked plate assembly. Non-mechanical inertial forces are employed to transfer condensate, as it forms, via centripetal action to the outer perimeter of each channel. A V-shaped groove, constructed on this outer edge of the spiral channel, increases local capillary forces thereby retaining the liquid. Air drag then pulls the liquid along to a collection region near the center of the device. Dry air produced by each parallel spiral channel is combined in a common orthogonal, out-of-plane conduit passing down the axial center of the stacked device. Similarly, the parallel condensate streams are combined and removed from the condenser/separator through yet another out-of-plane axial conduit. NC3 is an integration of conventional finned condenser operation, combined with static phase separation and capillary transport phenomena. A Mars' transit mission would be a logical application for this technology where gravity is absent and the use of vibrating, energy-intensive, motor-driven centrifugal separators is undesired. Here a vapor stream from either the Heat Melt Compactor or the Carbon dioxide Reduction Assembly, for example, would be dried to a dew point of 10 deg using a passive NC3 condenser/separator with the precious water condensate recycled to the water bus.

Efecto de surfactantes polimerizables en la distribución de tamaño de partícula, pH, viscosidad, contenidos de sólidos y de monómero residual de una resina estireno-butilacrilato Effect of polymerizable surfactants on particle size distribution, pH, viscosity, contents of solids and residual monomer of a styrene-butylacrylate resin

Directory of Open Access Journals (Sweden)

Luis A. Rios

2013-01-01

Full Text Available Se presentan los resultados de la polimerización en emulsión de una resina acrílica estirenada usando surfactantes polimerizables, los cuales presentan ventajas técnicas como baja formación de espuma, alta resistencia de la película al contacto con agua y buena estabilidad en la polimerización. Se evaluó el efecto de estos surfactantes polimerizables en la distribución de tamaños de partícula de la resina; además se determinaron propiedades finales de la resina tales como porcentaje de sólidos, porcentaje de monómero libre, viscosidad y pH. Estos resultados se compararon con los obtenidos usando surfactantes convencionales no polimerizables del tipo alquil fenol etoxilado y alquilarilpoliglicol éter sulfato de sodio. Los resultados indican que que se pueden remplazar totalmente los surfactantes convencionales no polimerizables por los surfactantes poliméricos evaluados sin afectar significativamente las propiedades de la resina, mientras que la sustitución parcial de los surfactantes no polimerizables por los polimerizables induce, en algunos casos, a la formación de partículas con mayor tamaño a las presentes en la muestra estándar.Results on the emulsion polymerization of a styrenated acrylic resin using polymerizable surfactants are presented. These surfactants exhibit low foaming, high film strength upon contact with water and good stability in the polymerization. A comparison was made with results for conventional non-polymerizable alkyl aryl polyglycol ether sulphate, sodium salt and nonylphenolethoxylate surfactants. The effect of these polymerizable surfactants on the particle size distribution of the resin was evaluated; in addition to determining the final properties of the resin such as solids content, free monomer content, viscosity and pH. It is feasible to totally replace non-polymerizable surfactants by the polymerizable surfactants evaluated without affecting significantly the properties of the resin, while

Bose-Einstein condensation of light: general theory.

Science.gov (United States)

Sob'yanin, Denis Nikolaevich

2013-08-01

A theory of Bose-Einstein condensation of light in a dye-filled optical microcavity is presented. The theory is based on the hierarchical maximum entropy principle and allows one to investigate the fluctuating behavior of the photon gas in the microcavity for all numbers of photons, dye molecules, and excitations at all temperatures, including the whole critical region. The master equation describing the interaction between photons and dye molecules in the microcavity is derived and the equivalence between the hierarchical maximum entropy principle and the master equation approach is shown. The cases of a fixed mean total photon number and a fixed total excitation number are considered, and a much sharper, nonparabolic onset of a macroscopic Bose-Einstein condensation of light in the latter case is demonstrated. The theory does not use the grand canonical approximation, takes into account the photon polarization degeneracy, and exactly describes the microscopic, mesoscopic, and macroscopic Bose-Einstein condensation of light. Under certain conditions, it predicts sub-Poissonian statistics of the photon condensate and the polarized photon condensate, and a universal relation takes place between the degrees of second-order coherence for these condensates. In the macroscopic case, there appear a sharp jump in the degrees of second-order coherence, a sharp jump and kink in the reduced standard deviations of the fluctuating numbers of photons in the polarized and whole condensates, and a sharp peak, a cusp, of the Mandel parameter for the whole condensate in the critical region. The possibility of nonclassical light generation in the microcavity with the photon Bose-Einstein condensate is predicted.

Condensation Enhancement by Surface Porosity: Three-Stage Mechanism.

Science.gov (United States)

Yarom, Michal; Marmur, Abraham

2015-08-18

Surface defects, such as pores, cracks, and scratches, are naturally occurring and commonly found on solid surfaces. However, the mechanism by which such imperfections promote condensation has not been fully explored. In the current paper we thermodynamically analyze the ability of surface porosity to enhance condensation on a hydrophilic solid. We show that the presence of a surface-embedded pore brings about three distinct stages of condensation. The first is capillary condensation inside the pore until it is full. This provides an ideal hydrophilic surface for continuing the condensation. As a result, spontaneous condensation and wetting can be achieved at lower vapor pressure than on a smooth surface.

CO2 capture by Condensed Rotational Separation

NARCIS (Netherlands)

Benthum, van R.J.; Kemenade, van H.P.; Brouwers, J.J.H.; Golombok, M.

2010-01-01

Condensed Rotational Separation (CRS) technology is a patented method to upgrade gas mixtures. A novel application is thecapture of CO2 from coal-combustion fired power stations: Condensed Contaminant Centrifugal Separation in Coal Combustion(C5sep). CRS involves partial condensation of a gas

Vortex sorter for Bose-Einstein condensates

International Nuclear Information System (INIS)

Whyte, Graeme; Veitch, John; Courtial, Johannes; Oehberg, Patrik

2004-01-01

We have designed interferometers that sort Bose-Einstein condensates into their vortex components. The Bose-Einstein condensates in the two arms of the interferometer are rotated with respect to each other through fixed angles; different vortex components then exit the interferometer in different directions. The method we use to rotate the Bose-Einstein condensates involves asymmetric phase imprinting and is itself new. We have modeled rotation through fixed angles and sorting into vortex components with even and odd values of the topological charge of two-dimensional Bose-Einstein condensates in a number of states (pure or superposition vortex states for different values of the scattering length). Our scheme may have applications for quantum information processing

Condensate treatment and oxygen control in power plants

International Nuclear Information System (INIS)

Sakai, Toshiaki; Iida, Kei; Ohashi, Shinichi.

1997-01-01

In thermal and nuclear power stations, the steam that operated turbines is cooled and condensed with condensers. The condensate is heated again with boilers, nuclear reactors or steam generators, but if corrosion products or impurities are contained in the condensate, corrosion and scale formation occur in boilers and others. The filtration facility and the desalting facility for condensate are installed to remove impurities, but water quality control is different in thermal, BWR and PWR plants, therefore, the treatment facilities corresponding to respective condensates have been adopted. In order to reduce the amount of clud generation, the treatment of injecting a small quantity of oxygen into condensate has been adopted. In thermal power plants, all volatile treatment is carried out, in which corrosion is prevented by the addition of ammonia and hydrazine to boiler feedwater. The condensate filters of various types and the NH 4 type condensate desalter for thermal power plants are described. In BWR power plants, steam is generated in nuclear reactors, therefore, the addition of chemicals into water is never carried out, and high purity neutral water is used. In PWR power plants, the addition of chemicals to water is done in the primary system, and AVT is adopted in the secondary system. Also the condensate treatment facilities are different for both reactors. (K.I.)

Boilers, evaporators, and condensers

International Nuclear Information System (INIS)

Kakac, S.

1991-01-01

This book reports on the boilers, evaporators and condensers that are used in power plants including nuclear power plants. Topics included are forced convection for single-phase side heat exchangers, heat exchanger fouling, industrial heat exchanger design, fossil-fuel-fired boilers, once through boilers, thermodynamic designs of fossil fuel-first boilers, evaporators and condensers in refrigeration and air conditioning systems (with respect to reducing CFC's) and nuclear steam generators

Avaliação da disponibilidade de manganês e ferro em solos pelo uso do método modificado da resina de troca iônica Evaluation of manganese and iron availability in soils by a modified ion exchange resin method

Directory of Open Access Journals (Sweden)

C. A. Abreu

2004-06-01

Full Text Available A avaliação do método modificado da resina de troca de íons para extração de Mn e Fe dos solos foi o objetivo desta pesquisa. Foram utilizadas 44 amostras de solo, cujos teores de Mn variaram de baixos a altos e de Fe de médios a altos. Como plantas-teste, utilizaram-se o milho e a soja, cultivadas em casa de vegetação. O Fe e o Mn do solo foram determinados, usando o método modificado da resina de troca de íons, DTPA, AB-DTPA, Mehlich-1 e Mehlich-3. Os coeficientes de correlação entre Mn no solo e Mn acumulado na parte aérea da soja foram: resina (0,62*, DTPA (0,58*, Mehlich-3 (0,54*, Mehlich-1 (0,51* e AB-DTPA (0,26NS. Para o milho, houve correlação entre Mn-solo e Mn-planta somente nas amostras de solo com baixos teores desse elemento, para todos os extratores, exceto para AB-DTPA. Concluiu-se que a resina foi tão eficiente quanto os extratores DTPA, M-1 e M-3 em avaliar a disponibilidade de Mn para a soja, e que nenhum extrator foi eficiente em avaliar a disponibilidade de Fe para as plantas de milho e soja, com 53 dias de idade, cultivadas em casa de vegetação.The objective of this research was to evaluate a modified ion exchange resin method for Mn and Fe extraction from soils. Forty-four soil samples presenting low, medium, and high Mn and medium to high Fe concentrations were used. Maize and soybeans plants were grown as test plants in a pot experiment in a greenhouse. Soil samples were analyzed for Mn and Fe using the modified ion exchange resin, DTPA, AB-DTPA, Mehlich-1, and Mehlich-3 methods. The correlation coefficients between soil Mn and Mn accumulated in the soybean shoot were: ion exchange resin (0.62*, DTPA (0.57*, Mehlich-3 (0.54*, Mehlich-1 (0.51*, and AB-DTPA (0.26. For maize, significant correlation coefficients between soil Mn and plant-Mn were obtained only when low-initial Mn soil samples were considered for all extractants, except for AB-DTPA. For soybeans, the modified ion exchange resin method was as

Condensed matter physics in electrochemistry

International Nuclear Information System (INIS)

Kornyshev, A.A.

1991-01-01

Some topics in electrochemistry are considered from the condensed matter physics viewpoint in relation to the problems discussed in this book. Examples of the successful application of condensed matter physics to electrochemistry are discussed together with prospective problems and pressing questions. (author). 127 refs, 4 figs

Competition between Bose-Einstein Condensation and Spin Dynamics.

Science.gov (United States)

Naylor, B; Brewczyk, M; Gajda, M; Gorceix, O; Maréchal, E; Vernac, L; Laburthe-Tolra, B

2016-10-28

We study the impact of spin-exchange collisions on the dynamics of Bose-Einstein condensation by rapidly cooling a chromium multicomponent Bose gas. Despite relatively strong spin-dependent interactions, the critical temperature for Bose-Einstein condensation is reached before the spin degrees of freedom fully thermalize. The increase in density due to Bose-Einstein condensation then triggers spin dynamics, hampering the formation of condensates in spin-excited states. Small metastable spinor condensates are, nevertheless, produced, and they manifest in strong spin fluctuations.

21 CFR 886.1380 - Diagnostic condensing lens.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic condensing lens. 886.1380 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1380 Diagnostic condensing lens. (a) Identification. A diagnostic condensing lens is a device used in binocular indirect ophthalmoscopy (a procedure...

The dynamics of Affleck-Dine condensate collapse

International Nuclear Information System (INIS)

Enqvist, Kari; McDonald, John

2000-01-01

In the MSSM, cosmological scalar field condensates formed along flat directions of the scalar potential (Affleck-Dine condensates) are typically unstable with respect to formation of Q-balls, a type of non-topological soliton. We consider the dynamical evolution of the Affleck-Dine condensate in the MSSM. We discuss the creation and linear growth, in F- and D-term inflation models, of the quantum seed perturbations which in the non-linear regime catalyse the collapse of the condensate to non-topological soliton lumps. We study numerically the evolution of the collapsing condensate lumps and show that the solitons initially formed are not in general Q-balls, but Q-axitons, a pseudo-breather which can have very different properties from Q-balls of the same charge. We calculate the energy and charge radiated from a spherically symmetric condensate lump as it evolves into a Q-axiton. We also discuss the implications for baryogenesis and dark matter

A study on passive containment cooling condensers in SBWR

International Nuclear Information System (INIS)

Kuran, S.; Soekmen; C. N.

2001-01-01

The passive containment cooling condensers (PCCC) are the crucial part of several new reactor designs, like European Simplified Boiling Water Reactor (ESBWR) and the SBWR. In a hypothetical accident, the pressurised steam non-condensable mixture from drywell is condensed in PCCCs, and condensate is returned to reactor vessel while non-condensable is vented through wet well. In this study, in order to examine the performance of PCCCs, condensation with presence of noncondensable is investigated. Condensation with different noncondensable types and conditions is studied on a PCCC model, which is developed by using RELAP5 Mod3.2 computer code

Polymerization time for a microwave-cured acrylic resin with multiple flasks Tempo de polimerização de resina acrílica em microondas, utilizando múltiplas muflas

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Daniela Maffei Botega

2004-03-01

Full Text Available This study aimed at establishing the polymerization time of a microwave-cured acrylic resin (AcronTM MC, simultaneously processing 2, 4, and 6 flasks. Required time was measured according to the parameters: monomer release in water, Knoop hardness, and porosity. Samples were made with AcronTM MC in different shapes: rectangular (32 x 10 x 2.5 mm for monomer release and porosity; and half-disc (30 mm in diameter x 4 mm in height for Knoop hardness. There were four experimental groups (n = 24 per group: G1 one flask (control; G2 two flasks; G3 four flasks, and G4 six flasks. At first, polymerization protocol was similar for all groups (3 min/450 W. Time was then adjusted for G2, G3, and G4, based on monomer release evaluation in the control group, obtained by spectrophotometer Beckman DU-70, with emitting wave of 206 nm. Knoop hardness test was performed using a Shimadzu HMV 2000 hardness tester, and 10 indentations were performed on each specimen's surface. Porosity was assessed after specimens were immersed in black ink and the pores counted in a microscope. Results showed that the complete polymerization of the resin occurred in 4.5 min for two flasks (G2; 8.5 min for four flasks (G3; and 13 min for six flasks (G4, all with 450 W. Statistical analysis revealed that the number of flasks does not interfere with polymerization, Knoop hardness, and porosity of the resin. Results showed that polymerization of microwave-curing resin with more than one flask is a viable procedure, as long as polymerization time is adjusted.O objetivo deste estudo foi o de determinar os tempos necessários para a polimerização padrão de uma resina acrílica em microondas, utilizando várias muflas simultaneamente. Os tempos necessários foram aferidos por parâmetros como monômeros liberados em água, dureza Knoop e porosidade. As amostras, confeccionadas em resina AcronTM MC, apresentavam as seguintes dimensões: para os parâmetros monômero residual e porosidade

Coherence and chaos in condensed matter

International Nuclear Information System (INIS)

Bishop, A.R.

1989-01-01

This paper discusses the following topics: nonlinearity in condensed matter; coherence and chaos in spatially extended condensed matter systems; nonlinearity and magnetism; and solitons and conducting polymers. 52 refs., 7 figs

Molecular simulation of steady-state evaporation and condensation in the presence of a non-condensable gas

Science.gov (United States)

Liang, Zhi; Keblinski, Pawel

2018-02-01

Using molecular dynamics simulations, we study evaporation and condensation of fluid Ar in the presence of a non-condensable Ne gas in a nanochannel. The evaporation and condensation are driven by the temperature difference, ΔTL, between the evaporating and condensing liquid surfaces. The steady-state evaporation and condensation fluxes (JMD) are also affected by the Ne concentration, ρNe, and the nanochannel length. We find that across a wide range of ΔTL and ρNe, JMD is in good agreement with the prediction from Stefan's law and from Schrage relationships. Furthermore, for ΔTL less than ˜20% of the absolute average temperature, we find that both steady-state heat and mass fluxes are proportional to ΔTL. This allows us to determine the interfacial resistance to the heat and mass transfer and compare it with the corresponding resistances in the gas phase. In this context, we derive an analytical expression for the effective thermal conductivity of the gas region in the nanochannel and the mass transport interfacial resistance equivalent length, i.e., the length of the nanochannel for which the resistance to the mass flow is the same as the interfacial resistance to the mass flow.

Recuperación de oro desde un medio amoniaco-tiosulfato con resina de intercambio iónico Amberlite IRA-410

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Navarro, P.

2006-10-01

Full Text Available The adsorption and elution of gold in thiosulfate-ammonia media were studied at laboratory level using the Amberlite IRA-410 ionic exchange resin. Tests were carried out in a stirred reactor, maintaining constant temperature (25 ºC, with a volume of solution/mass of resin ratio of 833,3 ml/g and during 3 h. The variables tested were the following: pH (9-11, thiosulfate concentration (0-0,5 M, ammonia concentration (0-0,5 M and selectivity in the presence of cupric ion. The obtained results indicate that gold adsorption was quick; the presence of thiosulfate decreased strongly the adsorption; and the presence of ammonia did not affect the adsorption mostly. The copper was in a certain measure a competitor of the gold, but its biggest negative effect was that acted as catalyst of the oxidizing reaction of thiosulfate (S₂O₃ ^2– to tetrathionate (S₄O₆ ^2– and trithionate (S₃O₆ ^2–, which can cause a partial elution of gold during the load stage. Also, the behavior of ClO– ₄, SO₃ ^2– and ClO– as eluents was studied in both gold and copper elution. These tests were also carried out in a stirred reactor, to constant temperature (25 ºC, with a volume of aqueous solution/mass of resin ratio of 200 ml/g and for 3 h. Results demonstrated that the copper was eluted more quickly that the gold in all the cases.

Se estudió, a nivel de laboratorio, la adsorción y desorción de oro utilizando la resina de intercambio iónico Amberlite IRA-410 en medio tiosulfato-amoniaco. Los ensayos se realizaron en un reactor agitado, manteniendo constante la temperatura en 25 ºC y con una razón volumen de disolución/masa de resina de 833,3 ml/g durante 3 h. Las variables evaluadas fueron las siguientes: pH de 9 a 11, concentración de tiosulfato de 0 a 0,5 M, concentración de amoniaco de 0 a 0,5 M y selectividad frente al i

The phase transition to an inhomogeneous condensate state

International Nuclear Information System (INIS)

Voskresensky, D.N.

1984-01-01

The Lagrangian (free energy) of the model with a complex scalar order parameter in which the phase transition to an inhomogeneous condensate state exists is constructed in the coordinate representation. In the case of condensation of charged particles (for example paired electrons) interaction with the electromagnetic field is included. The excitation spectrum in the presence of the condensate is found. The oscillations are strongly anisotropic. It is shown that superfluidity is absent for an uncharged system but that the charged one has the property of superconductivity. The important role of thermal fluctuations is demonstrated. They drastically change the behaviour of the condensate system. The condensation in a finite system is considered. A study is carried out for the behaviour of an inhomogeneous condensate in magnetic field. It is shown that the inhomogeneous condensate is a type II superconductor with Ginzburg-Landau parameter kappa >> 1, but that the structure of the mixed state of the system is unusual - consisting of plane layers of the normal phase, when Hsub(c1)< H< H'sub(c2). The distribution of condensate in the strong magnetic field H'sub(c2)< H< Hsub(c2) is also studied. (Auth.)

Deepak Condenser Model (DeCoM)

Science.gov (United States)

Patel, Deepak

2013-01-01

Development of the DeCoM comes from the requirement of analyzing the performance of a condenser. A component of a loop heat pipe (LHP), the condenser, is interfaced with the radiator in order to reject heat. DeCoM simulates the condenser, with certain input parameters. Systems Improved Numerical Differencing Analyzer (SINDA), a thermal analysis software, calculates the adjoining component temperatures, based on the DeCoM parameters and interface temperatures to the radiator. Application of DeCoM is (at the time of this reporting) restricted to small-scale analysis, without the need for in-depth LHP component integrations. To efficiently develop a model to simulate the LHP condenser, DeCoM was developed to meet this purpose with least complexity. DeCoM is a single-condenser, single-pass simulator for analyzing its behavior. The analysis is done based on the interactions between condenser fluid, the wall, and the interface between the wall and the radiator. DeCoM is based on conservation of energy, two-phase equations, and flow equations. For two-phase, the Lockhart- Martinelli correlation has been used in order to calculate the convection value between fluid and wall. Software such as SINDA (for thermal analysis analysis) and Thermal Desktop (for modeling) are required. DeCoM also includes the ability to implement a condenser into a thermal model with the capability of understanding the code process and being edited to user-specific needs. DeCoM requires no license, and is an open-source code. Advantages to DeCoM include time dependency, reliability, and the ability for the user to view the code process and edit to their needs.

Condensing and water supplying systems in an atomic power plant

International Nuclear Information System (INIS)

Shinmura, Akira.

1975-01-01

Object: To reduce heat loss and eliminate accumulation of drain in water supplying and heating units in an atomic power plant by providing a direct contact type drain cooler between a gland-exhauster vapor condenser and a condensing and de-salting means, the drain from each water supplying and heating unit being collected in said cooler for heating the condensed water. Structure: Condensed water from a condenser is fed by a low pressure condensing pump through an air ejector and gland-exhauster vapor condenser to the direct-contact type drain cooler and is condensed in each water supply heater. Next, it is heated by drain fed through a drain level adjuster valve and an orifice and then forced by a medium pressure condenser pump into the condensing and de-salting means. It is then supplied by a high pressure condensing pump into the successive water supply heater. (Kamimura, M.)

Keeping condensers clean

Energy Technology Data Exchange (ETDEWEB)

Wicker, K.

2006-04-15

The humble condenser is among the biggest contributors to a steam power plant's efficiency. But although a clean condenser can provide great economic benefit, a dirty one can raise plant heat rate, resulting in large losses of generation revenue and/or unnecessarily high fuel bills. Conventional methods for cleaning fouled tubes range form chemicals to scrapers to brushes and hydro-blasters. This article compares the available options and describes how one power station, Omaha Public Power District's 600 MW North Omaha coal-fired power station, cleaned up its act. The makeup and cooling water of all its five units comes from the Missouri River. 6 figs.

Systematic text condensation: a strategy for qualitative analysis.

Science.gov (United States)

Malterud, Kirsti

2012-12-01

To present background, principles, and procedures for a strategy for qualitative analysis called systematic text condensation and discuss this approach compared with related strategies. Giorgi's psychological phenomenological analysis is the point of departure and inspiration for systematic text condensation. The basic elements of Giorgi's method and the elaboration of these in systematic text condensation are presented, followed by a detailed description of procedures for analysis according to systematic text condensation. Finally, similarities and differences compared with other frequently applied methods for qualitative analysis are identified, as the foundation of a discussion of strengths and limitations of systematic text condensation. Systematic text condensation is a descriptive and explorative method for thematic cross-case analysis of different types of qualitative data, such as interview studies, observational studies, and analysis of written texts. The method represents a pragmatic approach, although inspired by phenomenological ideas, and various theoretical frameworks can be applied. The procedure consists of the following steps: 1) total impression - from chaos to themes; 2) identifying and sorting meaning units - from themes to codes; 3) condensation - from code to meaning; 4) synthesizing - from condensation to descriptions and concepts. Similarities and differences comparing systematic text condensation with other frequently applied qualitative methods regarding thematic analysis, theoretical methodological framework, analysis procedures, and taxonomy are discussed. Systematic text condensation is a strategy for analysis developed from traditions shared by most of the methods for analysis of qualitative data. The method offers the novice researcher a process of intersubjectivity, reflexivity, and feasibility, while maintaining a responsible level of methodological rigour.

The effect of non-condensable gas on direct contact condensation of steam/air mixture

International Nuclear Information System (INIS)

Lee, H. C.; Park, S. K.; Kim, M. H.

1998-01-01

To investigate the effects of noncondensable gas on the direct contact film condensation of vapor mixture, a series of experiments has been carried out. The rectangular duct inclined 87.deg. to the horizontal plane was used for this experiment. The average heat transfer coefficient of the steam-air mixture was obtained at the atmospheric pressure with four main parameters, air-mass fraction, vapor velocity, film Reynolds number,and the degree of water film subcooling having an influence on the condensation heat transfer coefficient. With the analysis on 88 cases of experiments, a correlation of the average Nusselt number for direct contact film condensation of steam-air mixture at a vertical wall proposed as functions of film Reynolds number, mixture Reynolds number, air mass fraction, and Jacob number. The average heat transfer coefficient for steam-air mixture condensation decreased significantly while air mass fraction increases with the same inlet mixture velocity and inlet film temperature. The average heat transfer coefficients also decreased with the degree of film subcooling increasing and were scarcely affected by film Reynolds number below the mixture Reynolds number about 30,000

Some issues in the ghost condensation scenario

International Nuclear Information System (INIS)

Anisimov, A.

2004-01-01

In the recently proposed 'ghost condensation' scenario a model of consistent infrared modification of gravity was suggested. We first review the basic ideas of this scenario. We discuss various phenomenological aspects of the ghost condensation, such as stability of the condensate, bounds on the UV cut-off scale of the corresponding effective field theory and other issues. (author)

Thermodynamic entanglement of magnonic condensates

Science.gov (United States)

Yuan, H. Y.; Yung, Man-Hong

2018-02-01

Over the past decade, significant progress has been achieved to create Bose-Einstein condensates (BECs) of magnetic excitations, i.e., magnons, at room temperature, which is a novel quantum many-body system with a strong spin-spin correlation, and contains potential applications in magnonic spintronics. For quantum information science, the magnonic condensates can become an attractive source of quantum entanglement, which plays a central role in most of the quantum information processing tasks. Here we theoretically study the entanglement properties of a magnon gas above and below the condensation temperature. We show that the thermodynamic entanglement of the spins is a manifestation of the off-diagonal long-range order; the entanglement of the condensate does not vanish, even if the spins are separated by an infinitely long distance, which is fundamentally distinct from the normal magnetic ordering below the Curie temperature. In addition, the phase-transition point occurs when the derivative of the entanglement changes abruptly. These results provide a theoretical foundation for a future investigation of the magnon BEC in terms of quantum entanglement.

Análise dos níveis de cinza de 4 resinas compostas micro-híbridas utilizando um sistema de radiografia digital direto =Analisys of the gray scale levels for 4 micro-hibrids composite resins using a radiograph direct digital system

Directory of Open Access Journals (Sweden)

Pereira, Ary Salazar Rubim et al.

2005-01-01

Full Text Available O objetivo deste estudo foi analisar os diferentes níveis de cinza de quatro resinas compostas micro-híbridas, através do sistema de radiografia digital direto Sens-a-Ray. As resinas utilizadas foram: Concept (Vigodent, Herculite (Sybron/Kerr, IntenS (Ivoclar Vivadent e Z 100 (3MESPE, na cor A2. Foram confeccionadas 3 placas de acrílico para cada espessura 2, 3 e 4 mm que possuíam dimensões de um filme periapical. Em todas as placas foram feitos quatro orifícios eqüidistantes com 4 mm de diâmetro onde as resinas compostas foram inseridas, esses orifícios apresentavam 4mm de diâmetro. As amostras foram radiografadas a 30 cm de distância foco-filme do sistema Sens-a-Ray por 0,8 segundo com aparelho de Raios-X (Dabi Atlante de 70 kV e 10 mA. A quantidade dos níveis de cinza, das resinas, foi aferida em pixels pelo sistema Sens-a-Ray. Foram obtidas as seguintes médias: Concept – 2 mm com 79,6; 3 mm com 85,4 e 4 mm com 96,7; Herculite – 2 mm com 65,1; 3 mm com 72,5 e 4 mm com 85,4; IntenS – 2 mm com 138,5; 3 mm com 147,3 e 4 mm com 153,7; Z 100 – 2 mm com 133,5; 3 mm com 143,8 e 4 mm com 150,6. Após os resultados foram submetidos ao teste estatístico ANOVA-Tukey com um nível de significância (p 0,05. A colorimetria foi utilizada para ilustrar a densidade óptica dos compósitos, com cores vermelho, verde e azul, representando, respectivamente do mais radiopaco para o menos radiopaco. Podemos concluir que na medida em que aumentou a espessura das placas os níveis de cinza também aumentaram. A resina Herculite apresentou os menores níveis de cinza, diferindo estatisticamente das demais. As resinas IntenS e Z 100 apresentaram maiores níveis de cinza que as demais. The aim of this study was analysed the different gray scale levels for 4 micro-hybrids composite resins, throught the direct digital radiography device, Sens-a-Ray. The composites used in this study were: Concept (Vigodent, Herculite (Sybron/Kerr, IntenS (Ivoclar

TRACE assessment on local condensation heat transfer in presence of non-condensable gas inside a vertical tube

Energy Technology Data Exchange (ETDEWEB)

Cho, Yong Jin; Ahn, Seung Hoon; Kim, Kap; Kim, Hho Jung [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2009-07-01

TRACE assessment was performed to investigate local condensation heat transfer coefficients in the presence of a noncondensable gas inside a vertical tube. The data obtained from pure steam and steam/nitrogen mixture condensation experiments were compared to study the effects of noncondensable nitrogen gas on the annular film condensation phenomena. The condenser tube had a small inner diameter of 13mm (about 1/2-in.) and this experiment had been performed to prove the effectiveness of the a Passive Residual Heat Removal System (PRHRS) of SMART (System-integrated Modular Advanced ReacTor), which is a small modular integral-type pressurized water reactor that is developed for the dual purposes of seawater desalination and small-scaled power generation. In the case of nitrogen presence, TRACE results show the converged results but the prediction is different from experimental data. The candidate reasons can be focused on several models, such as the film thickness calculation, surface area, and condensation heat transfer correlations, etc. In the case of pure steam condensation case, TRACE results shows large oscillations and do not converge. This should be investigated in detail to identify the reason. Until now, the oscillation in thermal hydraulic parameters results from the film thickness calculation and surface area calculation. For future works, the whole sets of the experiment will be assessed and the improvement of TRACE will be performed.

TRACE assessment on local condensation heat transfer in presence of non-condensable gas inside a vertical tube

International Nuclear Information System (INIS)

Cho, Yong Jin; Ahn, Seung Hoon; Kim, Kap; Kim, Hho Jung

2009-01-01

TRACE assessment was performed to investigate local condensation heat transfer coefficients in the presence of a noncondensable gas inside a vertical tube. The data obtained from pure steam and steam/nitrogen mixture condensation experiments were compared to study the effects of noncondensable nitrogen gas on the annular film condensation phenomena. The condenser tube had a small inner diameter of 13mm (about 1/2-in.) and this experiment had been performed to prove the effectiveness of the a Passive Residual Heat Removal System (PRHRS) of SMART (System-integrated Modular Advanced ReacTor), which is a small modular integral-type pressurized water reactor that is developed for the dual purposes of seawater desalination and small-scaled power generation. In the case of nitrogen presence, TRACE results show the converged results but the prediction is different from experimental data. The candidate reasons can be focused on several models, such as the film thickness calculation, surface area, and condensation heat transfer correlations, etc. In the case of pure steam condensation case, TRACE results shows large oscillations and do not converge. This should be investigated in detail to identify the reason. Until now, the oscillation in thermal hydraulic parameters results from the film thickness calculation and surface area calculation. For future works, the whole sets of the experiment will be assessed and the improvement of TRACE will be performed

Entropy generation in a condenser and related correlations

Directory of Open Access Journals (Sweden)

Askowski Rafał

2015-06-01

Full Text Available The paper presents an analysis of relations describing entropy generation in a condenser of a steam unit. Connections between entropy generation, condenser ratio, and heat exchanger effectiveness, as well as relations implied by them are shown. Theoretical considerations allowed to determine limits of individual parameters which describe the condenser operation. Various relations for average temperature of the cold fluid were compared. All the proposed relations were verified against data obtained using a simulator and actual measurement data from a 200 MW unit condenser. Based on data from a simulator it was examined how the sum of entropy rates, steam condenser effectiveness, terminal temperature difference and condenser ratio vary with the change in the inlet cooling water temperature, mass flow rate of steam and the cooling water mass flow rate.

Condensational theory of stationary tornadoes

International Nuclear Information System (INIS)

Makarieva, A.M.; Gorshkov, V.G.; Nefiodov, A.V.

2011-01-01

Using the Bernoulli integral for air streamline with condensing water vapor a stationary axisymmetric tornado circulation is described. The obtained profiles of vertical, radial and tangential velocities are in agreement with observations for the Mulhall tornado, world's largest on record and longest-lived among the three tornadoes for which 3D velocity data are available. Maximum possible vortex velocities are estimated. -- Highlights: → Water vapor condensation causes a logarithmic drop of air pressure towards tornado center. → The first ever theoretical description of tornado velocities is obtained. → The maximum vortex velocity grows logarithmically with decreasing tornado eye radius. → Air motion with high velocities can only develop in sufficiently large condensation areas.

Dynamics of inhomogeneous chiral condensates

Science.gov (United States)

Carlomagno, Juan Pablo; Krein, Gastão; Kroff, Daniel; Peixoto, Thiago

2018-01-01

We study the dynamics of the formation of inhomogeneous chirally broken phases in the final stages of a heavy-ion collision, with particular interest on the time scales involved in the formation process. The study is conducted within the framework of a Ginzburg-Landau time evolution, driven by a free energy functional motivated by the Nambu-Jona-Lasinio model. Expansion of the medium is modeled by one-dimensional Bjorken flow and its effect on the formation of inhomogeneous condensates is investigated. We also use a free energy functional from a nonlocal Nambu-Jona-Lasinio model which predicts metastable phases that lead to long-lived inhomogeneous condensates before reaching an equilibrium phase with homogeneous condensates.

Study on corrosion of thermal power plant condenser tubes

Energy Technology Data Exchange (ETDEWEB)

Mohammadi, Abdolreza Rashidi; Zhaam, Ali Akbar [Niroo Research Institute, end of Poonak Bakhtari blvd., Shahrak Ghods, Tehran (Iran)

2004-07-01

The aim of this investigation is to study kinds of corrosion mechanisms in thermal power plant condenser tubes. Condenser is a shell and tube heat exchanger in which cooling water flows through its tubes. While the steam from low pressure turbine passes within condenser tubes, it is condensed by cooling water. The exhausted steam from low pressure turbine is condensed on external surface of condenser tubes and heat is transferred to cooling water which flow into tubes. Tubes composition is usually copper-based alloys, stainless steel or titanium. Annual damages due to corrosion cause much cost for replacement and repairing metallic equipment and installations in electric power industry. Because of existence of different contaminants in water and steam cycle, condenser tubes surfaces are exposed to corrosion. Contaminants like oxygen, carbon dioxide, chloride ion and ammonia in water and steam cycle originate several damages such as pitting and crevice corrosion, erosion, galvanic attack, SCC, condensed corrosion, de-alloying in thermal power plant condenser. The paper first states how corrosion damage takes place in condensers and then introduces types of usual alloys used in condensers and also their corrosion behavior. In continuation, a brief explanation is presented about kinds of condenser failures due to corrosion. Then, causes and locations of different mechanisms of corrosion events on condenser tubes and effects of different parameters such as composition, temperature, chloride and sulfide ion concentration, pH, water velocity and biological precipitation are examined and finally protection methods are indicated. Also some photos of tubes specimens related to power plants are studied and described in each case of mentioned mechanisms. (authors)

Strangeness condensation and ''clearing'' of the vacuum

International Nuclear Information System (INIS)

Brown, G.E.; Kubodera, Kuniharu; Rho, M.; State Univ. of New York, Stony Brook

1987-01-01

We show that a substantial amount of strange quark-antiquark pair condensates in the nucleon required by the πN sigma term implies that kaons could condense in nuclear matter at a density about three times that of normal nuclear matter. This phenomenon can be understood as the ''cleansing'' of qanti q condensates from the QCD vacuum by a dense nuclear matter, resulting in a (partial) restoration of the chiral symmetry explicitly broken in the vacuum. It is suggested that the condensation signals a new phase distinct from that of quark plasma and that of ordinary dense hadronic matter. (orig.)

Status of the full scale component testing of the KERENA TM emergency condenser and Containment Cooling Condenser

International Nuclear Information System (INIS)

Leyer, S.; Maisberger, F.; Herbst, V.; Doll, M.; Wich, M.; Wagner, T.

2010-01-01

KERENA TM (SWR1000) is an innovative boiling water reactor concept with passive safety systems. In order to verify the functionality of the passive components required for the transient and accident management, the test facility INKA (Integral-Versuchstand Karlstein) is build in Karlstein (Germany). The key elements of the KERENA TM passive safety concept -the Emergency Condenser, the Containment Cooling Condenser, the Passive Core Flooding System and the Passive Pressure Pulse Transmitter - will be tested at INKA. The Emergency Condenser system transfers heat from the reactor pressure vessel to the core flooding pools of the containment. The heat introduced into the containment during accidents will be transferred to the main heat sink for passive accident management (Shielding/Storage Pool) via the Containment Cooling Condensers. Therefore both systems are part of the passive cooling chain connecting the heat source RPV (Reactor Pressure Vessel) with the heat sink. At the INKA test facility both condensers are tested in full scale setup, in order to determine the heat transfer capacity as function of the main input parameters. For the EC these are the RPV pressure, the RPV water level, the containment pressure and the water temperature of the flooding pools. For the Containment Cooling Condenser the heat transfer capacity is a function of the containment pressure, the water temperature of the Shielding/Storage Pool and the fraction of non -condensable gases in the containment. The status of the test program and the available test data will be presented. An outlook of the future test of the passive core flooding system and the integral system test including also the passive pressure pulse transmitter will be given. (authors)

Tensile bond strength between different glass ionomer cement and composite resin using three adhesive systems Avaliação da resistência de união interfacial entre diferentes cimentos de ionômero de vidro e resina composta, usando três sistemas adesivos

Directory of Open Access Journals (Sweden)

Patrícia Dias

2005-10-01

Full Text Available The purpose of this study was to evaluate the tensile bond strength (TBS among a Composite Resin (Filtek Z250 and six conventional Glass Ionomer Cements, three used for lining (Bioglass F, Vidrion F and Glass Ionomer L.C. and three for restorations (Ketac Fil, Vidrion R and Glass Ionomer type II etched and non etched, using three adhesive systems (Single Bond, Bond 1 and Stae. Thirty-six groups were made, ten samples for each group, totalizing 360 specimens. There were significant differences on TBS among groups. Group 31 (Glass Ionomer Cement type II showed the highest TBS (9.65 MPa in comparison to other tested groups. Group 16 (Glass Ionomer L.C presented the lowest TBS (2.72 MPa in comparison to all the other groups. Therefore, it can be concluded that the acid etching of the Glass Ionomer Cement is not necessary. Foi avaliada, ">in vitro, a resistência de união, por tração, entre uma Resina Composta micro-híbrida (Filtek Z-250 e seis Cimentos de Ionômero de Vidro (CIV convencionais: três utilizados para base/forramento (Bioglass F, Vidrion F e Glass Ionomer Lining Cement e três para restauração (Ketac Fil, Vidrion R e Glass Ionomer Cement type II, sem e com condicionamento ácido ortofosfórico a 37%, usando três sistemas adesivos (Single Bond, Bond 1 e Stae. Foram confeccionados 36 grupos de 10 corpos-de-prova cada, totalizando 360 espécimes. Para análise estatística, foi utilizado o teste de Tukey-Kramer. Dentre os três CIV de base/forramento, os grupos 2 e 5 (Bioglass F apresentaram valores mais altos de adesividade à resina (7,24 e 6,03 MPa respectivamente. Quanto aos três CIV de restauração, todos apresentaram maior resistência de união, superior aos de base/forramento, sendo que o Glass Ionomer Cement type II (Grupo 31 e Vidrion R apresentaram maior força de adesão (9,65 e 7,47 MPa à resina composta. O grupo 16 (Glass Ionomer L.C. mostrou menor adesividade à resina (2,72 MPa. Houve diferenças significantes

A Preliminary Study of Transverse Curvature Effects on Condensation Heat Transfer on Vertical Tube in the Presence of Non-condensable Gas

Energy Technology Data Exchange (ETDEWEB)

Lee, Yeon Gun; Kim, Sin [Jeju National Univ., Jeju (Korea, Republic of); Jerng, Dong Wook [Chung Ang Univ., Seoul (Korea, Republic of)

2013-10-15

In this study, the effect of the transverse curvature on the condensation HTC on a vertical tube in the presence of air is preliminarily investigated by using the analysis of boundary layer for free convective heat transfer. The results indicate that the heat transfer performance can be enhanced as the outer diameter of condenser tubes is small. To confirm this curvature effect, an experimental program to obtain the condensation heat transfer data for various values of tube diameter is indispensable. Currently, by a joint research project of Jeju National University and Chung-Ang University, a condensation test facility is being designed and constructed to acquire the condensation HTC data as shown in Fig. 3. From a series of experiment on a single vertical tube, the effects of not only the tube diameter but the inclination, the existence of fins and the local velocity of a bulk mixture by natural circulation will be evaluated precisely. An empirical correlation for the condensation heat transfer of a steam-air mixture will also be developed for design optimization and performance evaluation of the PCCS. The Passive Containment Cooling System (PCCS) provides passive means to remove the decay heat and protect the integrity of the containment during severe accidents. Korea, in which all the NPPs employ the concrete containment, may adopt a PCCS using internal condensers. In the event of the loss-of-coolant accident (LOCA), steam released from the reactor coolant system is mixed with air inside the containment and condensed on the outer surface of inclined condenser tubes. It is noted that, among previous theoretical and empirical models for condensation on outer wall in the presence of non-condensable gas, no one took into account the effect of a tube diameter. Though the condensation heat transfer coefficient may vary with transverse curvature of condenser tubes, such a curvature effect has not been reported so far. In this study, a preliminary analysis is conducted

A Preliminary Study of Transverse Curvature Effects on Condensation Heat Transfer on Vertical Tube in the Presence of Non-condensable Gas

International Nuclear Information System (INIS)

Lee, Yeon Gun; Kim, Sin; Jerng, Dong Wook

2013-01-01

In this study, the effect of the transverse curvature on the condensation HTC on a vertical tube in the presence of air is preliminarily investigated by using the analysis of boundary layer for free convective heat transfer. The results indicate that the heat transfer performance can be enhanced as the outer diameter of condenser tubes is small. To confirm this curvature effect, an experimental program to obtain the condensation heat transfer data for various values of tube diameter is indispensable. Currently, by a joint research project of Jeju National University and Chung-Ang University, a condensation test facility is being designed and constructed to acquire the condensation HTC data as shown in Fig. 3. From a series of experiment on a single vertical tube, the effects of not only the tube diameter but the inclination, the existence of fins and the local velocity of a bulk mixture by natural circulation will be evaluated precisely. An empirical correlation for the condensation heat transfer of a steam-air mixture will also be developed for design optimization and performance evaluation of the PCCS. The Passive Containment Cooling System (PCCS) provides passive means to remove the decay heat and protect the integrity of the containment during severe accidents. Korea, in which all the NPPs employ the concrete containment, may adopt a PCCS using internal condensers. In the event of the loss-of-coolant accident (LOCA), steam released from the reactor coolant system is mixed with air inside the containment and condensed on the outer surface of inclined condenser tubes. It is noted that, among previous theoretical and empirical models for condensation on outer wall in the presence of non-condensable gas, no one took into account the effect of a tube diameter. Though the condensation heat transfer coefficient may vary with transverse curvature of condenser tubes, such a curvature effect has not been reported so far. In this study, a preliminary analysis is conducted

Code-experiment comparison on wall condensation tests in the presence of non-condensable gases-Numerical calculations for containment studies

Energy Technology Data Exchange (ETDEWEB)

Malet, J., E-mail: jeanne.malet@irsn.fr [Institut de Radioprotection et de Surete Nucleaire (IRSN), PSN-RES, SCA, BP 68, 91192 Gif-sur-Yvette (France); Porcheron, E.; Dumay, F.; Vendel, J. [Institut de Radioprotection et de Surete Nucleaire (IRSN), PSN-RES, SCA, BP 68, 91192 Gif-sur-Yvette (France)

2012-12-15

Highlights: Black-Right-Pointing-Pointer Steam condensation on walls has been investigated in the TOSQAN vessel. Black-Right-Pointing-Pointer Experiments on 7 different tests have been performed. Black-Right-Pointing-Pointer Different steam injections and wall temperatures are used. Black-Right-Pointing-Pointer Simulations are performed in 2D using the TONUS code. Black-Right-Pointing-Pointer Code-experiments comparisons at many different locations show a good agreement. - Abstract: During the course of a severe Pressurized Water Reactor accident, pressurization of the containment occurs and hydrogen can be produced by the reactor core oxidation and distributed in the containment according to convection flows and wall condensation. Filmwise wall condensation in the presence of non-condensable gases is a subject of many interests and extensive studies have been performed in the past. Some empirical correlations have demonstrated their limit for extrapolation under different thermal-hydraulic conditions and at different geometries/scales. The French Institute for Radiological Protection and Nuclear Safety (IRSN) has developed a numerical tool and an experimental facility in order to investigate free convection flows in the presence of condensation. The objective of this paper is to present numerical results obtained on different wall condensation tests in 7 m{sup 3} volume vessel (TOSQAN facility), and to compare them with the experimental ones. Over eight tests are considered here, and code-experiment comparison is performed on many different locations, giving an extensive insight of the code assessment for air-steam mixture flows involving wall condensation in the presence of non-condensable gases.

SUSTENTAÇÃO DE ESMALTE COM IONÔMEROS DE VIDRO E RESINA COMPOSTA: EFEITO NA RESISTÊNCIA À FRATURA DAS CÚSPIDES DE DENTES RESTAURADOS SUPPORTING ENAMEL WITH GLASS IONOMER CEMENT AND COMPOSITE RESIN: EFFECT ON FRACTURE RESISTANCE OF CUSPS OF RESTORED TEETH

Directory of Open Access Journals (Sweden)

Angelo Stefano SECCO

1997-10-01

Full Text Available Este estudo determinou a resistência e o tipo de fratura do esmalte suportado pelos materiais restauradores ionômeros de vidro convencional e modificado por resina e resina composta, bem como a influência dessa técnica restauradora na resistência das cúspides dos dentes. A remoção da estrutura dental para o preparo de cavidades tipo classe II e a presença de esmalte socavado diminuiram significativamente a resistência das cúspides dos dentes em relação ao dente hígido (p This study determined the resistance to fracture and its pattern for enamel supported with conventional and modified glass ionomer cements, and composite resin restorative materials, as well as the influence of these restorative techniques on cuspal strength of teeth. Removal of dental structure by class II cavity preparations and unsupported enamel had decreased significantly the cuspal strength in relation to healthy teeth (p < 0.01. Restorative materials used to support enamel reduced the fracture rate of restored cusps, but did not increase the fracture resistance values statistically. All tested groups presented alterations in the fracture pattern

Avaliação da transmissão de luz através de zircónia: translucidez e polimerização de um cimento de resina: um estudo piloto

OpenAIRE

Pomares, Vânia Alexandra Cândido

2011-01-01

Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2011 O presente estudo laboratorial foi realizado com o objectivo de avaliar a influência da cerâmica de zircónia na polimerização de um cimento de resina fotopolimerizável, sendo igualmente avaliada a transmissão de luz através da mesma. Foram avaliadas três cerâmicas de zircónia: Lava (3M ESPE), Zirconia Traslucent (Zirkonzahn) e Zirconia Prettau (Zirkonzahn). De cada uma das cerâmicas mencionada...

Estimation of the Influence of Operational Factors on the Oxygen Content of the Turbine Condensate at the Outlet from the Condenser of Steam Turbine

Directory of Open Access Journals (Sweden)

Shempelev A. G.

2017-08-01

Full Text Available The aim of the article is to analyze the influence of different factors on the oxygen content in the condensate using the example of the condenser of the steam turbine unit T-110/120-130. For the first time, the authors of the article analyze in details how the basic parameters of the condenser's operation (the condenser heat load, the flow and temperature of the cooling water, the air inflow in the condenser, the condition of the heat exchange surface influence the oxygen content of the condensate. The authors come to the conclusion that with standard air inflow in the vacuum system, the equilibrium oxygen content, which corresponds to the norms in the condensate at the condenser outlet, is only possible in its operation modes when the steam flow to the condenser is more than 50% of the nominal flow and cooling water temperatures are equal to or greater than calculated for this type of condenser. The conclusions are confirmed by the experimental material. The results of the research are the basis for the development of measures aimed to increase the deaerating capacity of condensers depending on specific operating conditions.

Vortices in trapped Bose-Einstein condensates

International Nuclear Information System (INIS)

Jackson, B.

2000-09-01

In this thesis we solve the Gross-Pitaevskii equation numerically in order to model the response of trapped Bose-Einstein condensed gases to perturbations by electromagnetic fields. First, we simulate output coupling of pulses from the condensate and compare our results to experiments. The excitation and separation of eigenmodes on flow through a constriction is also studied. We then move on to the main theme of this thesis: the important subject of quantised vortices in Bose condensates, and the relation between Bose-Einstein condensation and superfluidity. We propose methods of producing vortex pairs and rings by controlled motion of objects. Full three-dimensional simulations under realistic experimental conditions are performed in order to test the validity of these ideas. We link vortex formation to drag forces on the object, which in turn is connected with energy transfer to the condensate. We therefore argue that vortex formation by moving objects is intimately related to the onset of dissipation in superfluids. We discuss this idea in the context of a recent experiment, using simulations to provide evidence of vortex formation in the experimental scenario. Superfluidity is also manifest in the property of persistent currents, which is linked to vortex stability and dynamics. We simulate vortex line and ring motion, and find in both cases precessional motion and thermodynamic instability to dissipation. Strictly speaking, the Gross-Pitaevskii equation is valid only for temperatures far below the BEC transition. We end the thesis by describing a simple finite-temperature model to describe mean-field coupling between condensed and non-condensed components of the gas. We show that our hybrid Monte-Carlo/FFT technique can describe damping of the lowest energy excitations of the system. Extensions to this model and future research directions are discussed in the conclusion. (author)

Analysis of experiments for vertical out-tube steam condensation in presence of non-condensable gases

International Nuclear Information System (INIS)

Su Jiqiang; Sun Zhongning; Fan Guangming; Guo Zixuan

2014-01-01

In order to investigate the influence of various parameters in the steam condensation heat transfer process with non-condensable gas, and to get a more suitable empirical correlation, the wall under-cooling, pressure and the content of non-condensable gas were studied outside a vertical tube by experiments. The results showed that: at the same pressure, the relationship between wall sub-cooling and HTC is exponential, and helium stratification does not happen within the experimental range. Based on the analysis of various experimental variables, combined with a large number of experimental data, a wider scope of application of the empirical correlation associated is obtained with the experimental value of the error within ±20%. (authors)

Continuous condensation device for vapors in the atmosphere

International Nuclear Information System (INIS)

Tricot, M.

1983-01-01

The continuous condensation device for vapors from the atmosphere is such those in which this atmosphere circulates in contact with a cold source involving the condensation of these vapors. It includes a thermoelectric module using the Peltier effect; the hot side is bonded to a heat sink and the cold side is in contact with an insulated condensation chamber in which flows the atmosphere charged with vapors to be condensated. The condensation chamber has a metallic structure through which a low voltage direct current is passed; this structure has small blades with holes, through which the condensate flows under gravity in the lower part of the chamber which have a hole to evacuate this liquid. The thermoelectric module comprises an assembly of thermocouples made of an array of alloy plates. The temperature inside the condensation chamber is maintained at just above 0 0 C. This device is used for the sampling of atmosphere water especially in the determination of tritium content of the atmosphere around nuclear installations [fr

Temporal dynamics of Bose-condensed gases

Energy Technology Data Exchange (ETDEWEB)

Trujillo Martinez, Mauricio

2014-03-19

We perform a detailed quantum dynamical study of non-equilibrium trapped, interacting Bose-condensed gases. We investigate Josephson oscillations between interacting Bose-Einstein condensates confined in a finite size double-well trap and the non-trivial time evolution of a coherent state placed at the center of a two dimensional optical lattice. For the Josephson oscillations three time scales appear. We find that Josephson junction can sustain multiple undamped oscillations up to a characteristic time scale τ{sub c} without exciting atoms out of the condensates. Beyond the characteristic time scale τ{sub c} the dynamics of the junction are governed by fast, non-condensed particles assisted Josephson tunnelling as well as the collisions between non-condensed particles. In the non-condensed particles dominated regime we observe strong damping of the oscillations due to inelastic collisions, equilibrating the system leading to an effective loss of details of the initial conditions. In addition, we predict that an initially self-trapped BEC state will be destroyed by these fast dynamics. The time evolution of a coherent state released at the center of a two dimensional optical lattice shows a ballistic expansion with a decreasing expansion velocity for increasing two-body interactions strength and particle number. Additionally, we predict that if the two-body interactions strength exceeds a certain value, a forerunner splits up from the expanding coherent state. We also observe that this system, which is prepared far from equilibrium, can evolve to a quasistationary non-equilibrium state.

Asymmetric condensed dark matter

Energy Technology Data Exchange (ETDEWEB)

Aguirre, Anthony; Diez-Tejedor, Alberto, E-mail: aguirre@scipp.ucsc.edu, E-mail: alberto.diez@fisica.ugto.mx [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA, 95064 (United States)

2016-04-01

We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate must be lighter than a few tens of eV so that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large dark matter-to-photon ratios and very weak interactions with standard model particles.

Decay of non-equilibrium polariton condensate in semiconductors

International Nuclear Information System (INIS)

Beloussov, I.V.; Shvera, Y.M.

1993-08-01

Excitation dynamics of polariton quantum fluctuations arising in direct-gap semi-conductor as a result of parametric decay of non-equilibrium polariton condensate with non-zero wave vector is studied. The predominant mechanism of polariton scattering is supposed to be exciton-exciton interaction. Steady state which corresponds to the case of dynamic equilibrium between the polariton condensate and quantum fluctuations is obtained. Distribution functions of non-condensate polaritons are localized in the resonant regions, corresponding to two-particle excitation of polaritons from the condensate. The spectrum of elementary excitations in steady state coincides with usual polariton energy with the shift proportional to initial density of polariton condensate. (author). 25 refs

Biomolecular condensates: organizers of cellular biochemistry.

Science.gov (United States)

Banani, Salman F; Lee, Hyun O; Hyman, Anthony A; Rosen, Michael K

2017-05-01

Biomolecular condensates are micron-scale compartments in eukaryotic cells that lack surrounding membranes but function to concentrate proteins and nucleic acids. These condensates are involved in diverse processes, including RNA metabolism, ribosome biogenesis, the DNA damage response and signal transduction. Recent studies have shown that liquid-liquid phase separation driven by multivalent macromolecular interactions is an important organizing principle for biomolecular condensates. With this physical framework, it is now possible to explain how the assembly, composition, physical properties and biochemical and cellular functions of these important structures are regulated.

Active condensation of water by plants

Directory of Open Access Journals (Sweden)

Prokhorov Alexey Anatolievich

2013-10-01

Full Text Available This paper is devoted to some peculiarities of water condensation on the surface of plants . Arguments in support of the hypothesis that in decreasing temperature of leaves and shoots below the dew point, the plant can actively condense moisture from the air, increasing the duration of dewfall are presented. Evening dewfall on plant surfaces begins before starting the formation of fog. Morning condensation continues for some time after the air temperature exceeds the dew point . The phenomenon in question is found everywhere, but it is particularly important for plants in arid ecosystems.

Landau-Migdal parameters and pion condensation

Energy Technology Data Exchange (ETDEWEB)

Tatsumi, Toshitaka [Department of Physics, Kyoto Univ., Kyoto (Japan)

1999-08-01

The possibility of pion condensation, one of the long-standing issues in nuclear physics, is reexamined in the light of the recent experimental data on the giant Gamow-Teller resonance. The experimental result tells that the coupling of nucleon particle-hole states with {delta} isobar-hole states in the spin-isospin channel should be weaker than that previously believed. It, in turn, implies that nuclear matter has the making of pion condensation at low densities. The possibility and implications of pion condensation in the heavy-ion collisions and neutron stars should be seriously reconsidered. (author)

Titanium condenser tubes. Problems and their solution for wider application to large surface condensers. [PWR

Energy Technology Data Exchange (ETDEWEB)

Sato, S; Sugiyama, S; Nagata, K; Nanba, K; Shimono, M [Sumitomo Light Metal Industries Ltd., Tokyo (Japan)

1977-06-01

The corrosion resistance of titanium in sea water is extremely excellent, but titanium tubes are expensive, and the copper alloy tubes resistant in polluted sea water were developed, therefore they were not used practically. In 1970, ammonia attack was found on the copper alloy tubes in the air-cooled portion of condensers, and titanium tubes have been used as the countermeasure. As the result of the use, the galvanic attack on copper alloy tube plates with titanium tubes as cathode and the hydrogen absorption at titanium tube ends owing to excess electrolytic protection was observed, but the corrosion resistance of titanium tubes was perfect. These problems can be controlled by the application of proper electrolytic protection. The condensers with all titanium tubes adopted recently in USA are intended to realize perfectly no-leak condensers as the countermeasure to the corrosion in steam generators of PWR plants. Regarding large condensers of nowadays, three problems are pointed out, namely the vibration of condenser tubes, the method of joining tubes and tube plates, and the tubes of no coolant leak. These three problems in case of titanium tubes were studied, and the problem of the fouling of tubes was also examined. The intervals of supporting plates for titanium tubes should be narrowed. The joining of titanium tubes and titanium tube plates by welding is feasible and promising. The cleaning with sponge balls is effective to control fouling.

Collapsing dynamics of attractive Bose-Einstein condensates

DEFF Research Database (Denmark)

Bergé, L.; Juul Rasmussen, J.

2002-01-01

The self-similar collapse of 3D and quasi-2D atom condensates with negative scattering length is examined. 3D condensates are shown to blow up following the scenario of weak collapse, for which 3-body recombination weakly dissipates the atoms. In contrast, 2D condensates undergo a strong collapse......, that absorbs a significant amount of particles. (C) 2002 Elsevier Science B.V. All rights reserved....

Assessment of RELAP5/MOD3 with condensation experiment for pure steam condensation in a vercal tube

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Jae; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1999-12-31

The film condensation models in RELAP5/MOD3.1 and RELAP5/MOD3.2 are assessed with the data of experiment performed in the scaled down condensation experimental facility with a single vertical tube of inner diameter of 46 mm in the range of pressure 0.1 {approx} 7.5 MPa for the PSCS(Passive Secondary Condenser System). Both MOD3.1 and MOD3.2 don`t shows any reliable predictions of the experimental data. The RELAP5/MOD3.1 overpredicts the heat transfer coefficients of experiment, whereas the RELAP5/MOD3.2 underpredicts those data. It is recommended that the film condensation model in RELAP5/MOD3.2 should be modified to have a larger heat transfer coefficient than those of the present model to give the reliable predictions. 7 refs., 6 figs., 1 tab. (Author)

Assessment of RELAP5/MOD3 with condensation experiment for pure steam condensation in a vercal tube

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Jae; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1998-12-31

The film condensation models in RELAP5/MOD3.1 and RELAP5/MOD3.2 are assessed with the data of experiment performed in the scaled down condensation experimental facility with a single vertical tube of inner diameter of 46 mm in the range of pressure 0.1 {approx} 7.5 MPa for the PSCS(Passive Secondary Condenser System). Both MOD3.1 and MOD3.2 don`t shows any reliable predictions of the experimental data. The RELAP5/MOD3.1 overpredicts the heat transfer coefficients of experiment, whereas the RELAP5/MOD3.2 underpredicts those data. It is recommended that the film condensation model in RELAP5/MOD3.2 should be modified to have a larger heat transfer coefficient than those of the present model to give the reliable predictions. 7 refs., 6 figs., 1 tab. (Author)

Method and apparatus for controlled condensation isotope separation

International Nuclear Information System (INIS)

Sullivan, J.A.; Lee, J.T. Jr.; Kim, K.C.

1981-01-01

The invention provides a method for producing controlled homogeneous condensation of a molecular feed gas containing several isotopes. The feed gas flows at supersonic rates through an expansion nozzle under conditions at which the gas would normally condense. The gas is irradiated with laser radiation of a wavelength that selectively excites those molecules in the feed gas that contain a particular isotope, thus preventing their condensation. Condensate particles may be aerodynamically separated from the flowing gas stream

Bose-Einstein condensation and indirect excitons: a review.

Science.gov (United States)

Combescot, Monique; Combescot, Roland; Dubin, François

2017-06-01

We review recent progress on Bose-Einstein condensation (BEC) of semiconductor excitons. The first part deals with theory, the second part with experiments. This Review is written at a time where the problem of exciton Bose-Einstein condensation has just been revived by the understanding that the exciton condensate must be dark because the exciton ground state is not coupled to light. Here, we theoretically discuss this missed understanding before providing its experimental support through experiments that scrutinize indirect excitons made of spatially separated electrons and holes. The theoretical part first discusses condensation of elementary bosons. In particular, the necessary inhibition of condensate fragmentation by exchange interaction is stressed, before extending the discussion to interacting bosons with spin degrees of freedom. The theoretical part then considers composite bosons made of two fermions like semiconductor excitons. The spin structure of the excitons is detailed, with emphasis on the crucial fact that ground-state excitons are dark: indeed, this imposes the exciton Bose-Einstein condensate to be not coupled to light in the dilute regime. Condensate fragmentations are then reconsidered. In particular, it is shown that while at low density, the exciton condensate is fully dark, it acquires a bright component, coherent with the dark one, beyond a density threshold: in this regime, the exciton condensate is 'gray'. The experimental part first discusses optical creation of indirect excitons in quantum wells, and the detection of their photoluminescence. Exciton thermalisation is also addressed, as well as available approaches to estimate the exciton density. We then switch to specific experiments where indirect excitons form a macroscopic fragmented ring. We show that such ring provides efficient electrostatic trapping in the region of the fragments where an essentially-dark exciton Bose-Einstein condensate is formed at sub-Kelvin bath

Condenser Design for the Proposed AM600 NPP

Energy Technology Data Exchange (ETDEWEB)

Rahman, Md. Mizanur; Abdallah, Khaled Atya Ahmed; Field, Robert M. [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

2015-10-15

The design goals are to make the condenser more robust and compact with a reduced component count. The AM600 condenser design also has new features as described below. Considering that the minimum heat sink temperature for potentially emergent nuclear countries is on the order of 21.deg. C or higher, a turbine design with a single low pressure rotor can be considered without sacrificing thermal efficiency. The condenser back pressure range for the considered markets is on the order of 2 to 3 in-HgA. With these boundary conditions, the AM600 condenser duty can be met with a single pressure zone design with a total of eight (8) titanium tube bundles (four (4) per pass) divided into four isolable sections. Due to the compact design (i.e., accepting exhaust from only one low pressure cylinder), both axial ends of the condenser are unobstructed and available for attachment of extended flash chambers, diverting inflows away from the tube bundles. The single shell design of this condenser then allows for an innovative design feature, namely the extended flash chambers. This permits the routing of dump, drain, vent, and bypass flows directly to these chambers, bypassing the condenser shell. Within the condenser shell, this design eliminates impingement plates, impingement boxes, and spargers. Failure of these components represents an ongoing source of condenser tube damage in operating nuclear units, requiring significant resources for outage inspections. The extended flash chamber approach also has a number of other advantages as delineated above.

Study on UF6 condensing receiving system improvement

International Nuclear Information System (INIS)

Zhang Zhenxing; Li Yingfeng; Li Zhenfeng; He Ping; Wang Yanping; Tian Yushan

2012-01-01

In order to improve receiving capacity of UF 6 condensing system, the pressure release mode is changed through modifying gas phase inlet of the first-grade condenser, thus pressure release time is reduced from 13.1 h to 8.1 h. Be- cause of improvement of utility condensers of the two product lines, both the flexibility of feeding nitrogen and the emergency capacity of condensers are improved greatly. And modification of fluid transferring and sampling system make the remains in system transfer flexibly. The practise shows that metal direct recovery rises to the extent, and capacity of the first-grade condensing receiving system improves 8.4%, which strongly guarantees fluorination production safely, continuously and stably run. (authors)

Oxidación catalítica de a-pineno con metiltrioxorenio inmovilizado en resinas

Directory of Open Access Journals (Sweden)

Lina María González R.

2004-01-01

Full Text Available Se investigó la inmovilización del catalizador homogéneo metiltrioxorenio (MTO, CH3ReO3, en resinas basadas en vinilpiridina sintetizadas por diferentes procedimientos. Los catalizadores se caracterizaron por espectroscopia IR y UV-Vis y la composición elemental de nitrógeno y renio se determinó por ICP-MS. Los análisis FTIR indicaron la presencia de grupos ReO3 y ReO en los catalizadores heterogeneizados; en los análisis UV-Vis se observaron nuevas bandas después de tratar los soportes con MTO. La eficiencia de incorporación de renio fue mayor en PVP comercial y en el copolímero preparado en suspensión. Además, la oxidación del soporte disminuyó la incorporación del MTO. Los catalizadores se evaluaron en la oxidación de α-pineno con peróxido de hidrógeno. Los catalizadores soportados en PVP presentaron baja conversión del α-pineno (7%, pero la selectividad al epóxido de α-pineno fue alta (92%. Además, la más alta conversión del α-pineno (50% se obtuvo con el MTO en los soportes copolimerizados y oxidados; con MeCN/DCM como solvente se obtuvieron principalmente aldehído canfolénico y sobrerol, productos de rearreglo del epóxido. En general, la eficiencia del oxidante fue baja y ésta se favoreció en terbutanol y acetato de etilo como solventes

Condenser design for AMTEC power conversion

Science.gov (United States)

Crowley, Christopher J.

1991-01-01

The condenser and the electrodes are the two elements of an alkali metal thermal-to-electric conversion (AMTEC) cell which most greatly affect the energy conversion performance. A condenser is described which accomplishes two critical functions in an AMTEC cell: management of the fluid under microgravity conditions and optimization of conversion efficiency. The first function is achieved via the use of a controlled surface shape, along with drainage grooves and arteries to collect the fluid. Capillary forces manage the fluid in microgravity and dominate hydrostatic effects on the ground so the device is ground-testable. The second function is achieved via a smooth film of highly reflective liquid sodium on the condensing surface, resulting in minimization of parasitic heat losses due to radiation heat transfer. Power conversion efficiencies of 25 percent to 30 percent are estimated with this condenser using present technology for the electrodes.

Relações entre fósforo extraído por resina e respostas da cultura do alho vernalizado à adubação fosfatada em cinco solos com e sem adubação orgânica

Directory of Open Access Journals (Sweden)

L. T. Büll

1998-09-01

Full Text Available Estudaram-se respostas à adubação fosfatada pelo alho vernalizado cv. Roxo Pérola de Caçador em cinco solos com diferentes classes texturais, com e sem adubação orgânica, visando contribuir para o estabelecimento de curva de calibração para fósforo extraído por resina de troca iônica. Foram instalados dois experimentos entre maio e outubro de 1995 e 1996, em vasos (16 L, em casa de vegetação telada do Departamento de Ciência do Solo da Faculdade de Ciências Agronômicas/UNESP, município de Botucatu (SP. Cada experimento constituiu um fatorial com cinco solos e seis doses de fósforo (original, 50, 100, 200, 400 e 800 mg dm-3 de P. A adubação orgânica foi aplicada apenas no primeiro ano, na dosagem de 40 t ha-1 de esterco bovino decomposto. Verificou-se que a aplicação de matéria orgânica dificultou a discriminação dos níveis de fósforo extraído pela resina entre os tratamentos com menores doses de adubação fosfatada. A elevação nos níveis de fósforo aumentou a concentração de clorofila e de N, P, K e Mn e reduziu a concentração de Mg nas folhas; não foram observados efeitos antagônicos do P sobre a absorção de Zn. O nível crítico de fósforo extraído pela resina para os solos utilizados situou-se em torno de 50 mg dm-3 de P, enquanto a concentração foliar crítica de fósforo nas plantas de alho foi de 2,5 g kg-1 de P. A adubação orgânica, na dosagem recomendada para o estado de São Paulo, pode substituir a adubação fosfatada na cultura do alho vernalizado.

Capillary Condensation in 8 nm Deep Channels.

Science.gov (United States)

Zhong, Junjie; Riordon, Jason; Zandavi, Seyed Hadi; Xu, Yi; Persad, Aaron H; Mostowfi, Farshid; Sinton, David

2018-02-01

Condensation on the nanoscale is essential to understand many natural and synthetic systems relevant to water, air, and energy. Despite its importance, the underlying physics of condensation initiation and propagation remain largely unknown at sub-10 nm, mainly due to the challenges of controlling and probing such small systems. Here we study the condensation of n-propane down to 8 nm confinement in a nanofluidic system, distinct from previous studies at ∼100 nm. The condensation initiates significantly earlier in the 8 nm channels, and it initiates from the entrance, in contrast to channels just 10 times larger. The condensate propagation is observed to be governed by two liquid-vapor interfaces with an interplay between film and bridging effects. We model the experimental results using classical theories and find good agreement, demonstrating that this 8 nm nonpolar fluid system can be treated as a continuum from a thermodynamic perspective, despite having only 10-20 molecular layers.

Condensate cosmology: Dark energy from dark matter

International Nuclear Information System (INIS)

Bassett, Bruce A.; Parkinson, David; Kunz, Martin; Ungarelli, Carlo

2003-01-01

Imagine a scenario in which the dark energy forms via the condensation of dark matter at some low redshift. The Compton wavelength therefore changes from small to very large at the transition, unlike quintessence or metamorphosis. We study cosmic microwave background (CMB), large scale structure, supernova and radio galaxy constraints on condensation by performing a four parameter likelihood analysis over the Hubble constant and the three parameters associated with Q, the condensate field: Ω Q , w f and z t (energy density and equation of state today, and redshift of transition). Condensation roughly interpolates between ΛCDM (for large z t ) and SCDM (low z t ) and provides a slightly better fit to the data than ΛCDM. We confirm that there is no degeneracy in the CMB between H and z t and discuss the implications of late-time transitions for the Lyman-α forest. Finally we discuss the nonlinear phase of both condensation and metamorphosis, which is much more interesting than in standard quintessence models

Modeling of Kerena Emergency Condenser

Science.gov (United States)

Bryk, Rafał; Schmidt, Holger; Mull, Thomas; Wagner, Thomas; Ganzmann, Ingo; Herbst, Oliver

2017-12-01

KERENA is an innovative boiling water reactor concept equipped with several passive safety systems. For the experimental verification of performance of the systems and for codes validation, the Integral Test Stand Karlstein (INKA) was built in Karlstein, Germany. The emergency condenser (EC) system transfers heat from the reactor pressure vessel (RPV) to the core flooding pool in case of water level decrease in the RPV. EC is composed of a large number of slightly inclined tubes. During accident conditions, steam enters into the tubes and condenses due to the contact of the tubes with cold water at the secondary side. The condensed water flows then back to the RPV due to gravity. In this paper two approaches for modeling of condensation in slightly inclined tubes are compared and verified against experiments. The first approach is based on the flow regime map. Depending on the regime, heat transfer coefficient is calculated according to specific semi-empirical correlation. The second approach uses a general, fully-empirical correlation. The models are developed with utilization of the object-oriented Modelica language and the open-source OpenModelica environment. The results are compared with data obtained during a large scale integral test, simulating loss of coolant accident performed at Integral Test Stand Karlstein (INKA). The comparison shows a good agreement.Due to the modularity of models, both of them may be used in the future in systems incorporating condensation in horizontal or slightly inclined tubes. Depending on his preferences, the modeller may choose one-equation based approach or more sophisticated model composed of several exchangeable semi-empirical correlations.

In-stack condensible particulate matter measurement and permitting issues

International Nuclear Information System (INIS)

Corio, L.A.; Sherwell, J.

1997-01-01

Based on the results of recent epidemiological studies and assessments of the causes of visibility degradation, EPA is proposing to regulate PM2.5 emissions. PM can be classified as either filterable or condensible PM. Condensible PM includes sulfates, such as sulfuric acid. Sulfates typically account for at least half of the total dry fine PM mass in the atmosphere. Power plant SO x -based emissions make a significant contribution to ambient fine PM levels in the eastern US. Although much of this mass is derived from secondary chemical reactions in the atmosphere, a portion of this sulfate is emitted directly from stacks as condensible PM. The potential condensible PM fraction associated with coal-burning boiler emissions is somewhat uncertain. The characterization of PM emissions from these sources has been, until recently, based on in-stack filterable PM measurements only. To determine the relative magnitude of condensible PM emissions and better understand condensible PM measurement issues, a review and analysis of actual EPA Method 202 results and state-developed hybrid condensible PM methods were conducted. A review of available Method 202 results for several coal-burning boilers showed that the condensible PM, on average, comprises 60% of the total PM10. A review of recent results for state-developed measurement methods for condensible PM for numerous coal-burning boilers indicated that condensible PM accounted for, on average, approximately 49% of total PM. Caution should be exercised in the use of these results because of the seemingly unresolved issue of artifact formation, which may bias the Method 202 and state-developed methods results on the high side. Condensible PM10 measurement results and issues, and potential ramifications of including condensible PM10 emissions in the PSD permit review process are discussed. Selected power plants in Maryland are discussed as examples

Cold Vacuum Drying facility condensate collection system design description

International Nuclear Information System (INIS)

PITKOFF, C.C.

1999-01-01

This document describes the Cold Vacuum Drying Facility (CVDF) condensate collection system (CCS). The function of the CCS is to collect cooling coil condensate from air-handling units in the CVDF and to isolate the condensate in collection tanks until the condensate is determined to be acceptable to drain to the effluent drain collection basin

Condensation in Microchannels

National Research Council Canada - National Science Library

Ameel, Timothy

1999-01-01

.... Evaporators and condensers for meso-scale energy systems will most likely be constructed of microchannels due to the microfabrication constraints that limit most structures to two-dimensional planar geometries...

Condensation Analysis of Steam/Air Mixtures in Horizontal Tubes

International Nuclear Information System (INIS)

Lee, Kwon Yeong; Bae, Sung Won; Kim, Moo Hwan

2008-01-01

Perhaps the most common flow configuration in which a convective condensation occurs is a flow in a horizontal circular tube. This configuration is encountered in air-conditioning and refrigeration condensers as well as condensers in Rankine power cycles. Although a convective condensation is also sometimes contrived to occur in a co-current vertical downward flow, a horizontal flow is often preferred because the flow can be repeatedly passed through the heat exchanger core in a serpentine fashion without trapping liquid or vapor in the return bends. Many researchers have investigated a in-tube condensation for horizontal heat exchangers. However, almost all of them obtained tube section-averaged data without a noncondensable gas. Recently, Wu and Vierow have experimentally studied the condensation of steam in a horizontal heat exchanger with air present. In order to measure the condenser tube inner surface temperatures and to calculate the local heat fluxes, they developed an innovative thermocouple design that allowed for nonintrusive measurements. Here we developed a theoretical model using the heat and mass analogy to analyze a steam condensation with a noncondensable gas in horizontal tubes

Local condensate depletion at trap center under strong interactions

Science.gov (United States)

Yukalov, V. I.; Yukalova, E. P.

2018-04-01

Cold trapped Bose-condensed atoms, interacting via hard-sphere repulsive potentials are considered. Simple mean-field approximations show that the condensate distribution inside a harmonic trap always has the shape of a hump with the maximum condensate density occurring at the trap center. However, Monte Carlo simulations at high density and strong interactions display the condensate depletion at the trap center. The explanation of this effect of local condensate depletion at trap center is suggested in the frame of self-consistent theory of Bose-condensed systems. The depletion is shown to be due to the existence of the anomalous average that takes into account pair correlations and appears in systems with broken gauge symmetry.

Bose-Einstein condensation in real space

International Nuclear Information System (INIS)

Valencia, J.J.; Llano, M. de; Solis, M.A.

2004-01-01

We show how Bose-Einstein condensation (BEC) occurs not only in momentum space but also in coordinate (or real) space. Analogies between the isotherms of a van der Waals classical gas of extended (or finite-diameter) identical atoms and the point (or zero-diameter) particles of an ideal BE gas allow concluding that, in contrast with the classical case, the volume per particle vanishes in the pure BE condensate phase precisely because the boson diameters are zero. Thus a BE condensate forms in real space without exhibiting a liquid branch as does the classical gas. (Author)

Enhanced Evaporation and Condensation in Tubes

Science.gov (United States)

Honda, Hiroshi

A state-of-the-art review of enhanced evaporation and condensation in horizontal microfin tubes and micro-channels that are used for air-conditioning and refrigeration applications is presented. The review covers the effects of flow pattern and geometrical parameters of the tubes on the heat transfer performance. Attention is paid to the effect of surface tension which leads to enhanced evaporation and condensation in the microfin tubes and micro-channels. A review of prior efforts to develop empirical correlations of the heat transfer coefficient and theoretical models for evaporation and condensation in the horizontal microfin tubes and micro-channels is also presented.

Open string decoupling and tachyon condensation

International Nuclear Information System (INIS)

Chalmers, G.

2001-01-01

The amplitudes in perturbative open string theory are examined as functions of the tachyon condensate parameter. The boundary state formalism demonstrates the decoupling of the open string modes at the non-perturbative minima of the tachyon potential via a degeneration of open world-sheets and identifies an independence of the coupling constants g s and g YM at general values of the tachyon condensate. The closed sector is generated at the quantum level; it is also generated at the classical level through the condensation of the propagating open string modes on the D-brane degrees of freedom.

Dynamics of capillary condensation in aerogels.

Science.gov (United States)

Nomura, R; Miyashita, W; Yoneyama, K; Okuda, Y

2006-03-01

Dynamics of capillary condensation of liquid 4He in various density silica aerogels was investigated systematically. Interfaces were clearly visible when bulk liquid was rapidly sucked into the aerogel. Time evolution of the interface positions was consistent with the Washburn model and their effective pore radii were obtained. Condensation was a single step in a dense aerogel and two steps in a low density aerogel. Crossover between the two types of condensation was observed in an intermediate density aerogel. Variety of the dynamics may be the manifestation of the fractal nature of aerogels which had a wide range of distribution of pore radii.

Quark virtuality and QCD vacuum condensates

International Nuclear Information System (INIS)

Zhou Lijuan; Ma Weixing

2004-01-01

Based on the Dyson-Schwinger equations (DSEs) in the 'rainbow' approximation, the authors investigate the quark virtuality in the vacuum state and quantum-chromodynamics (QCD) vacuum condensates. In particular, authors calculate the local quark vacuum condensate and quark-gluon mixed condensates, and then the virtuality of quark. The calculated quark virtualities are λ u,d 2 =0.7 GeV 2 for u, d quarks, and λ s 2 =1.6 GeV 2 for s quark. The theoretical predictions are consistent with empirical values used in QCD sum rules, and also fit to lattice QCD predictions

Efficient, Long-Life Biocidal Condenser, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Environmental control systems for manned lunar and planetary bases will require condensing heat exchangers to control humidity. Condensing surfaces must be...

21 CFR 573.200 - Condensed animal protein hydrolysate.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Condensed animal protein hydrolysate. 573.200... ANIMALS Food Additive Listing § 573.200 Condensed animal protein hydrolysate. (a) Identity. The condensed animal protein hydrolysate is produced from the meat byproducts scraped from cured (salted) hides taken...

Condensation induced non-condensable accumulation in a non-vented horizontal pipe connected with an elbow and a vertical pipe

International Nuclear Information System (INIS)

Stevanovic, V.D.; Stosic, Z.V.; Stoll, U.

2005-01-01

In this paper the radiolytic gases (hydrogen and oxygen) accumulation is investigated numerically for the pipe geometry consisting of a horizontal pipe closed at one end, and connected via a downward directed elbow with a vertical pipe open at its bottom end. This configuration is a typical part of many pipeline systems or measuring lines. The steam inside the pipes is condensed due to heat losses to the surrounding atmosphere, the condensate is drained and the concentration of the remaining noncondensable radiolytic gases is increased. Three dimensional numerical simulations are performed with the thermal-hydraulic and physico-chemical code HELIO, especially developed for the simulation and analyses of radiolytic gases accumulation in pipelines. The HELIO code model is based on the mass, momentum and energy conservation equations for the gas mixture and wall condensate film flow, as well as on the transport equations for non-condensable diffusion and convection. At the liquid film surface, the phases are coupled through the no-slip velocity condition and the mass transfer due to steam condensation and non-condensable absorption and degassing. Obtained numerical results show the gas mixture and condensate liquid film flow fields. In case of here analyzed geometry, the gas mixture circulates in the elbow and the horizontal pipe due to buoyancy forces induced by concentration and related density differences. The circulation flow prevents the formation of the radiolytic gases concentration front. The non-condensable radiolytic gases are transported from the pipe through the open end by the mechanisms of diffusion and convection. The analyzed geometry is the same as in case of venting pipe mounted on the steam pipeline. The results are of practical importance since they show that radiolytic gases accumulation does not occur in the geometry of the venting pipes. (authors)

Theory of decoherence in Bose-Einstein condensate interferometry

Energy Technology Data Exchange (ETDEWEB)

Dalton, B J [ARC Centre for Quantum-Atom Optics and Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne, Victoria 3122 (Australia)

2007-05-15

A full treatment of decoherence and dephasing effects in BEC interferometry has been developed based on using quantum correlation functions for treating interferometric effects. The BEC is described via a phase space distribution functional of the Wigner type for the condensate modes and the positive P type for the non-condensate modes. Ito equations for stochastic condensate and non-condensate field functions replace the functional Fokker-Planck equation for the distribution functional and stochastic averages of field function products determine the quantum correlation functions.

Leak detection in turbo group condensers using helium

International Nuclear Information System (INIS)

Gomez Cores, C.; Lloret, J.

1997-01-01

This method allows a rapid location of leaks (small or not) in the pipelines of a turbo group condenser, before opening the condenser boxes and no need of stooping the turbo group operation. This operation can last two hours maximum depending on the volume of the box or semi box. The technique consists of injecting helium into the water side and detecting it in the steam side, in the outlet of not condensable gases of the ejector. In the same way, probable air inlet to the condenser can be proved (auxiliary systems, turbo group joints to the condenser, etc.) in order to improve the vacuum and/or reduce the quantity of oxygen dissolved in the water of the steam side. (author) [es

Integral Reactor Containment Condensation Model and Experimental Validation

Energy Technology Data Exchange (ETDEWEB)

Wu, Qiao [Oregon State Univ., Corvallis, OR (United States); Corradini, Michael [Univ. of Wisconsin, Madison, WI (United States)

2016-05-02

This NEUP funded project, NEUP 12-3630, is for experimental, numerical and analytical studies on high-pressure steam condensation phenomena in a steel containment vessel connected to a water cooling tank, carried out at Oregon State University (OrSU) and the University of Wisconsin at Madison (UW-Madison). In the three years of investigation duration, following the original proposal, the planned tasks have been completed: (1) Performed a scaling study for the full pressure test facility applicable to the reference design for the condensation heat transfer process during design basis accidents (DBAs), modified the existing test facility to route the steady-state secondary steam flow into the high pressure containment for controllable condensation tests, and extended the operations at negative gage pressure conditions (OrSU). (2) Conducted a series of DBA and quasi-steady experiments using the full pressure test facility to provide a reliable high pressure condensation database (OrSU). (3) Analyzed experimental data and evaluated condensation model for the experimental conditions, and predicted the prototypic containment performance under accidental conditions (UW-Madison). A film flow model was developed for the scaling analysis, and the results suggest that the 1/3 scaled test facility covers large portion of laminar film flow, leading to a lower average heat transfer coefficient comparing to the prototypic value. Although it is conservative in reactor safety analysis, the significant reduction of heat transfer coefficient (50%) could under estimate the prototypic condensation heat transfer rate, resulting in inaccurate prediction of the decay heat removal capability. Further investigation is thus needed to quantify the scaling distortion for safety analysis code validation. Experimental investigations were performed in the existing MASLWR test facility at OrST with minor modifications. A total of 13 containment condensation tests were conducted for pressure

The Dynamics of Aerosols in Condensational Scrubbers

DEFF Research Database (Denmark)

Johannessen, Jens Tue; Christensen, Jan A.; Simonsen, Ole

1997-01-01

A mathematical model for the simulation of the dynamics of aerosol change in condensational scrubbers and scrubbing condensers is proposed. The model is applicable for packed column gas/liquid contact when plug flow can be assumed. The model is compared with experimental data for particle removal...... for their estimation is proposed. The behaviour of scrubbers and condensers for some important technical applications is demonstrated by model simulations. (C) 1997 Elsevier Science Ltd....

Comportamiento mecánico de mezclas de resina furanopoxídica con polisulfuros para su uso como adhesivos de alta resistencia. Acción de las cargas estáticas. // Mechanical behaviour of epoxi-modified furan polymer blends with polysulfyde for use as high st

Directory of Open Access Journals (Sweden)

D. Díaz Batista

1999-01-01

Full Text Available La modificación de polímeros furánicos con otros de diferentes propiedades ha sido una vía para lograr el mejoramiento deestos impartiéndoles propiedades específicas. La incorporación de polisulfuros como tiokol caucho a la resina furfural-acetonamodificada con grupos epoxídicos es estudiada en base a ensayos estáticos observándose un incremento discreto sobre laadhesividad de las mezclas y un aumento notable en el módulo elástico. Se estudió el comportamiento de estos adhesivos sobreun grupo de substratos de uso estructural.Palabras claves: resinas, pol isul furos, adhesivos de al ta resi st encia.__________________________________________________________________________AbstractModification of furan polymers with other ones having different behaviour has been an alternative to improve them developingspecific properties. Blends of polysulfide in the rubbery form with epoxi-modified furan resin are studied based on static tests.It has been observed a small increase in adhesive strength and a higher elastic modulus. Four substrates commonly used instructural parts were evaluated.Key words: Resin, polysul fyde, high strength adhesive.

Propriedades mecânicas de materiais compósitos à base de cimento Portland e resina epoxi Mechanical properties of composite materials based on portland cement and epoxy resin

Directory of Open Access Journals (Sweden)

T. H. Panzera

2010-03-01

Full Text Available O estudo de materiais de alto desempenho e multifuncionais, como os compósitos poliméricos cimentícios, tem sido o foco de inúmeras pesquisas na indústria da construção civil. Este trabalho investiga o efeito da combinação de uma fase polimérica termorrígida, uma resina epóxi, com cimento Portland branco estrutural, seguido da avaliação da resistência à compressão e módulo de elasticidade. Este compósito, quando comparado individualmente com as suas matérias-prima originais, promove um aumento da resistência mecânica à compressão, redução da massa específica e, também uma mudança significativa do comportamento mecânico. As mudanças nas propriedades mecânicas estão associadas à hidratação da fase cimentícia na presença da resina, fato comprovado através da análise espectroscópica na região do infravermelho.The study of multi-functional materials of high performance, as the polymeric-cementitious composites, has been the focus of several researches in the industry of the civil engineering. This work investigates the effect of the combination of a thermorigid epoxy phase and the white Portland cement, followed by the evaluation of its compressive strength and modulus of elasticity. This composite, when the phases are individually compared, provides an increase of the compressive strength, a reduction of the density, and a significant change of the mechanical behaviour. The changes in mechanical behaviour are associated with the hydration of cement in the presence of resin, which was evident after infrared spectroscopy analysis.

Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

KAUST Repository

Gemici, Zekeriyya; Schwachulla, Patrick I.; Williamson, Erik H.; Rubner, Michael F.; Cohen, Robert E.

2009-01-01

Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

KAUST Repository

Gemici, Zekeriyya

2009-03-11

Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

Targeted functionalization of nanoparticle thin films via capillary condensation.

Science.gov (United States)

Gemici, Zekeriyya; Schwachulla, Patrick I; Williamson, Erik H; Rubner, Michael F; Cohen, Robert E

2009-03-01

Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane).

Comparative study during condensation of R152 a and R134 a with presence of non-condensable gas inside a vertical tube

Science.gov (United States)

Charef, Adil; Feddaoui, M'barek; Najim, Monssif; Meftah, Hicham

2018-04-01

A computational study of the liquid film condensation from vapour-gas mixtures of HFC refrigerants inside a vertical tube is performed. The external wall of the tube is subjected to constant temperature. The model uses an implicit finite difference method to solve the governing equations for the liquid film and gas flow together including the boundary and interfacial matching conditions. Parametric computations were realised to examine the effects of inlet Reynolds number, tube length, and inlet temperature of the gas mixtures on the condensation mechanism. A comparative study between the results obtained for studied R152 a and R134 a with presence of non-condensable gas is made. The predicted results indicate that the condensation of R152 a-air corresponds to a higher accumulated condensation m c d and local heat transfer coefficient h T when compared to R134 a-air in the same conditions. Increasing the inlet Reynolds number or the tube length improve the condensation. Additionally, lower non-condensable gas in R152 a - a i r substantially enhances the heat and mass exchanges.

Condensate growth in trapped Bose gates

NARCIS (Netherlands)

Bijlsma, M.J.; Zaremba, E.; Stoof, H.T.C.

2000-01-01

We study the dynamics of condensate fromation in an inhomogeneous trapped Bose gas with a positive interatomic scattering length. We take into account both the nonequilibrium kinetics of the thermal cloud and the Hartree-Fock mean-field efects in the condensed and the noncondensed parts of the gas.

Condensate growth in trapped Bose gases

NARCIS (Netherlands)

Bijlsma, M.J.; Zaremba, E.; Stoof, H.T.C.

2000-01-01

We study the dynamics of condensate formation in an inhomogeneous trapped Bose gas with a positive interatomic scattering length. We take into account both the nonequilibrium kinetics of the thermal cloud and the Hartree-Fock mean-field effects in the condensed and the noncondensed parts of the gas.

Accretion of Ghost Condensate by Black Holes

Energy Technology Data Exchange (ETDEWEB)

Frolov, A

2004-06-02

The intent of this letter is to point out that the accretion of a ghost condensate by black holes could be extremely efficient. We analyze steady-state spherically symmetric flows of the ghost fluid in the gravitational field of a Schwarzschild black hole and calculate the accretion rate. Unlike minimally coupled scalar field or quintessence, the accretion rate is set not by the cosmological energy density of the field, but by the energy scale of the ghost condensate theory. If hydrodynamical flow is established, it could be as high as tenth of a solar mass per second for 10MeV-scale ghost condensate accreting onto a stellar-sized black hole, which puts serious constraints on the parameters of the ghost condensate model.

Nonlinear behavior of the radiative condensation instability

International Nuclear Information System (INIS)

McCarthy, D.; Drake, J.F.

1991-01-01

An investigation of the nonlinear behavior of the radiative condensation instability is presented in a simple one-dimensional magnetized plasma. It is shown that the radiative condensation is typically a nonlinear instability---the growth of the instability is stronger once the disturbance reaches finite amplitude. Moreover, classical parallel thermal conduction is insufficient by itself to saturate the instability. Radiative collapse continues until the temperature in the high density condensation falls sufficiently to reduce the radiation rate

Modeling of Kerena Emergency Condenser

Directory of Open Access Journals (Sweden)

Bryk Rafał

2017-12-01

Full Text Available KERENA is an innovative boiling water reactor concept equipped with several passive safety systems. For the experimental verification of performance of the systems and for codes validation, the Integral Test Stand Karlstein (INKA was built in Karlstein, Germany. The emergency condenser (EC system transfers heat from the reactor pressure vessel (RPV to the core flooding pool in case of water level decrease in the RPV. EC is composed of a large number of slightly inclined tubes. During accident conditions, steam enters into the tubes and condenses due to the contact of the tubes with cold water at the secondary side. The condensed water flows then back to the RPV due to gravity. In this paper two approaches for modeling of condensation in slightly inclined tubes are compared and verified against experiments. The first approach is based on the flow regime map. Depending on the regime, heat transfer coefficient is calculated according to specific semi-empirical correlation. The second approach uses a general, fully-empirical correlation. The models are developed with utilization of the object-oriented Modelica language and the open-source OpenModelica environment. The results are compared with data obtained during a large scale integral test, simulating loss of coolant accident performed at Integral Test Stand Karlstein (INKA. The comparison shows a good agreement.Due to the modularity of models, both of them may be used in the future in systems incorporating condensation in horizontal or slightly inclined tubes. Depending on his preferences, the modeller may choose one-equation based approach or more sophisticated model composed of several exchangeable semi-empirical correlations.

Confirmatory tests of full-scale condensers for SBWR

International Nuclear Information System (INIS)

Masoni, P.; Botti, S.; Fitzsimmons, G.W.

1993-01-01

A full-scale isolation condenser and a full-scale passive containment cooling condenser for the Simplified Boiling Water Reactor (SBWR) will be tested to confirm the thermal-hydraulic and structural design characteristics of these components. The condensers provide vital roles in removing heat from the reactor vessel and the containment during certain design basis events. This paper describes the condensers and the test facilities which are under construction and summarizes the test objectives, the planned instrumentation, and the conditions to be tested. The results of some pre-test performance predictions, calculated with the TRACG code are presented. The results of the testing program are expected to demonstrate that the condenser designs will provide the required heat removal capacity and will survive the design basis temperature/pressure cycles without structural damage

Condensate and feedwater systems, pumps, and water chemistry. Volume seven

International Nuclear Information System (INIS)

Anon.

1986-01-01

Subject matter includes condensate and feedwater systems (general features of condensate and feedwater systems, condenser hotwell level control, condensate flow, feedwater flow), pumps (principles of fluid flow, types of pumps, centrifugal pumps, positive displacement pumps, jet pumps, pump operating characteristics) and water chemistry (water chemistry fundamentals, corrosion, scaling, radiochemistry, water chemistry control processes, water pretreatment, PWR water chemistry, BWR water chemistry, condenser circulating water chemistry

CONVECTION IN CONDENSIBLE-RICH ATMOSPHERES

Energy Technology Data Exchange (ETDEWEB)

Ding, F. [Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637 (United States); Pierrehumbert, R. T., E-mail: fding@uchicago.edu [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom)

2016-05-01

Condensible substances are nearly ubiquitous in planetary atmospheres. For the most familiar case—water vapor in Earth’s present climate—the condensible gas is dilute, in the sense that its concentration is everywhere small relative to the noncondensible background gases. A wide variety of important planetary climate problems involve nondilute condensible substances. These include planets near or undergoing a water vapor runaway and planets near the outer edge of the conventional habitable zone, for which CO{sub 2} is the condensible. Standard representations of convection in climate models rely on several approximations appropriate only to the dilute limit, while nondilute convection differs in fundamental ways from dilute convection. In this paper, a simple parameterization of convection valid in the nondilute as well as dilute limits is derived and used to discuss the basic character of nondilute convection. The energy conservation properties of the scheme are discussed in detail and are verified in radiative-convective simulations. As a further illustration of the behavior of the scheme, results for a runaway greenhouse atmosphere for both steady instellation and seasonally varying instellation corresponding to a highly eccentric orbit are presented. The latter case illustrates that the high thermal inertia associated with latent heat in nondilute atmospheres can damp out the effects of even extreme seasonal forcing.

New state of matter: Bose-Einstein condensation

International Nuclear Information System (INIS)

Anon.

1995-01-01

70 years after work by the Indian physicist Satyendra Nath Bose led Einstein to predict the existence of a new state of matter, the Bose-Einstein condensate has finally been seen. The discovery was made in July by a team from Colorado, and was followed one month later by a second sighting at Rice University at Houston, Texas. It is Bose's theoretical framework governing the behaviour of the particles we now call bosons which led to Einstein's prediction. Unlike fermions, which obey the Pauli exclusion principle of only one resident particle per allowed quantum state, any number of bosons can pack into an identical quantum state. This led Einstein to suggest that under certain conditions, bosons would lose their individual identities, condensing into a kind of 'superboson'. This condensate forms when the quantum mechanical waves of neighbouring bosons overlap, hiding the identity of the individual particles. Such a condition is difficult to achieve, since most long-lived bosons are composite particles which tend to interact and stick together before a condensate can emerge. Extremely low temperatures and high densities are required to overcome this problem. As bosons lose energy and cool down, their wavelengths become longer, and they can be packed close enough together to merge into a condensate. Up until now, however, the extreme conditions needed have not been attainable. Nevertheless, hints of the Bose- Einstein condensate have been inferred in phenomena such as superconductivity and liquid helium superfluidity. Condensates could also play an important role in particle physics and cosmology, explaining, for example, why the pion as a bound quark-antiquark state is so much lighter than the three-quark proton. A hunt to create a pure Bose- Einstein condensate has been underway for over 15 years, with different groups employing different techniques to cool their bosons. The two recent successes have been achieved by incorporating several

Condensed images for evaluating gastric motility patterns

Energy Technology Data Exchange (ETDEWEB)

Tatsch, K.; Schroettle, W.; Kirsch, C.-M. (Munich Univ. (Germany, F.R.). Dept. of Radiology)

1991-04-01

A condensed imaging technique was applied to gastric emptying studies to investigate (a) whether different types of motility disorders may be distinguished by characteristic image patterns and (b) whether the findings obtained provide additional information compared to standard quantitative measurements. Condensed images and quantitative data of gastric emptying were evaluated in 75 consecutive patients with normal function and various disorders such as peptic ulcer, postvagotomy, pyloric obstruction, dumping syndrome, gastoparesis etc. Condensed images were generated from a gastric region of interest. They display the distribution and behaviour of a radioactive test meal in a space-time matrix, whose horizontal and vertical dimensions are temporal and spatial, respectively. As shown in a series of representative examples condensed images disclose a variety of well-defined image patterns reflecting different pathophysiological mechanisms. This qualitative characterization of gastric emptying patterns provided in 34 of the 75 patients (45%) important new information compared to quantitative data. The application of condensed imaging techniques to gastric emptying studies (complementary to quantitative measurements) may, therefore, enhance the diagnostic value of scintigraphic techniques. (author).

Condensation on a cooled plane upright wall

International Nuclear Information System (INIS)

Fortier, Andre.

1975-01-01

The vapor condensation along a cooled upright plane wall was studied. The theoretical and experimental results obtained in the simple case, give the essential characteristics of the phenomenon of condensation along a cold wall that keeps the vapor apart from the coolant inside a surface condenser. The phenomenon presents two different appearances according as the wall is wetted or not by the liquid. In the first case a continuous liquid film runs down the wall and a conventional Nusselt calculation gives the film thickness and the heat exchange coefficient between a pure saturated vapor and the cold wall. The calculation is developed in detail and the effect of a vapor flow along the film is discussed as well as that of the presence of a noncondensable gas inside the vapor. In the second case, separated liquid drops are formed on the wall, the phenomenon is called ''dropwise condensation'' and the heat exchange coefficients obtained are much higher than with film condensation. The theoretical aspects of the problem are discussed with some experimental results [fr

Influence of a cobalt-chromium metal framework on surface roughness and Knoop hardness of visible light-polymerized acrylic resins Influência de estrutura metálica de cobalto-cromo na rugosidade e dureza Knoop superficiais de resinas acrílicas polimerizadas por luz visível

Directory of Open Access Journals (Sweden)

Joane Augusto de Souza Júnior

2006-06-01

Full Text Available Although visible light-polymerized acrylic resins have been used in removable partial dentures, it is not clear whether the presence of a metal framework could interfere with their polymerization, by possibly reflecting the light and affecting important properties, such as roughness and hardness, which would consequently increase biofilm accumulation. The aim of this study was to compare the roughness and Knoop hardness of a visible light-polymerized acrylic resin and to compare these values to those of water-bath- and microwave-polymerized resins, in the presence of a metal framework. Thirty-six specimens measuring 30.0 x 4.0 ± 0.5 mm of a microwave- (Onda Cryl, a visible light- (Triad and a water-bath-polymerized (Clássico (control acrylic resins containing a cobalt-chromium metal bar were prepared. After processing, specimens were ground with 360 to 1000-grit abrasive papers in a polishing machine, followed by polishing with cloths and 1-µm diamond particle suspension. Roughness was evaluated using a profilometer (Surfcorder SE 1700 and Knoop hardness (Kg/mm² was assayed using a microhardness tester (Shimadzu HMV 2000 at distances of 50, 100, 200, 400 and 800 µm from the metal bar. Roughness and Knoop hardness means were submitted to two-way ANOVA and compared by Tukey and Kruskal Wallis tests at a 5% significance level Statistically significant differences were found (p0.05. Within the limitations of this in vitro study, it was concluded that the presence of metal did not influence roughness and hardness values of any of the tested acrylic resins.Resinas acrílicas polimerizadas por luz visível têm sido indicadas para a confecção de próteses parciais removíveis. Entretanto, não há estudos determinando se a presença de estrutura metálica interfere ou não na polimerização, considerando que essa estrutura pode refletir a luz e afetar propriedades como rugosidade e dureza e, consequentemente, facilitar o acúmulo de biofilme

Dimensioning of emergency condensers in accordance with safety requirements

Energy Technology Data Exchange (ETDEWEB)

Palavecino, C [SIEMENS, Energieerzeugung, Offenbach (Germany)

1996-12-01

The emergency condensers are heat exchangers consisting of a parallel arrangement of horizontal U-tubes between two common heads. The tope header is connected via piping to the reactor vessel steam space, while the lower header is connected to the reactor vessel below the reactor vessel water level. The heat exchangers are located in a pool filled with cold water. The emergency condensers and the reactor vessel thus form a system of communicating pipes. At normal reactor water level, the emergency condensers are flooded with cold, non-flowing water. No heat transfer takes place in this condition. If there is a drop in the reactor water level, the heat exchanging surfaces are gradually uncovered and the incoming steam condenses on the cold surfaces. The cold condensate in returned to the reactor vessel. In this way, heat is removed from the reactor vessel and water simultaneously supplied to the reactor vessel. This means that the emergency condensers function as a heat removal system while at the same time serving as HP and LP coolant injection systems. The emergency condensers operate with the highest possible degree of passivity imaginable, namely through a drop in the reactor vessel water level alone, requiring neither control systems nor power supply. The design of the emergency condensers must meet the requirements dictated by the thermal and the hydraulic conditions. Taking into consideration a redundancy degree of N + 2, a specific thermal rating of 63 MW per emergency condenser results for a reactor with an output of 2778 MW. The total performance of the emergency condenser system in thus 252 MW, or 9.1% of reactor output. The probability of failure of the emergency condenser of Siemens SWR 1000 is approximately 10{sup -4} per demand, while that of the older emergency condenser designs is approximately 2 to 3 x 10{sup -3} per demand. (author). 7 figs, 2 tabs.

Condensates in quantum chromodynamics and the cosmological constant

Science.gov (United States)

Brodsky, Stanley J.; Shrock, Robert

2011-01-01

Casher and Susskind [Casher A, Susskind L (1974) Phys Rev 9:436–460] have noted that in the light-front description, spontaneous chiral symmetry breaking is a property of hadronic wavefunctions and not of the vacuum. Here we show from several physical perspectives that, because of color confinement, quark and gluon condensates in quantum chromodynamics (QCD) are associated with the internal dynamics of hadrons. We discuss condensates using condensed matter analogues, the Anti de Sitter/conformal field theory correspondence, and the Bethe–Salpeter–Dyson–Schwinger approach for bound states. Our analysis is in agreement with the Casher and Susskind model and the explicit demonstration of “in-hadron” condensates by Roberts and coworkers [Maris P, Roberts CD, Tandy PC (1998) Phys Lett B 420:267–273], using the Bethe–Salpeter–Dyson–Schwinger formalism for QCD-bound states. These results imply that QCD condensates give zero contribution to the cosmological constant, because all of the gravitational effects of the in-hadron condensates are already included in the normal contribution from hadron masses.

Effect on non-condensable gas on steam injector

International Nuclear Information System (INIS)

Kawamoto, Y.; Abe, Y.; Iwaki, C.; Narabayashi, T.; Mori, M.; Ohmori, S.

2004-01-01

Next-generation reactor systems have been under development aiming at simplified system and improvement of safety and credibility. A steam injector has a function of a passive pump without large motor or turbo-machinery, and has been investigated as one of the most important component of the next-generation reactor. Its performance as a pump depends on direct contact condensation phenomena between a supersonic steam and a sub-cooled water jet. Although non-condensable gases are well known for reducing heat transfer, the effect of the non-condensable gas on the condensation of supersonic steam on high-speed water jet has not been cleared. The present paper presents an experimental study of condensation of supersonic steam around turbulent water jet with model steam injector made by transparent plastic. The experimental apparatus is described. The visual observation was carried out by using high-speed camera. The non-condensable gas effect on the pump performance and flow characteristics are clarified by the image processing technique for the jet shape and gas-liquid interface behavior. (authors)

Steam blowdown experiments with the condensation pool test rig

International Nuclear Information System (INIS)

Purhonen, H.; Puustinen, M.; Laine, J.; Raesaenen, A.; Kyrki-Rajamaeki, R.; Vihavainen, J.

2005-01-01

During a possible loss-of-coolant accident (Local) a large amount of non-condensable (nitrogen) and condensable (steam) gas is blown from the upper drywell of the containment to the condensation pool through the blowdown pipes at the boiling water reactors (BWRs). The wet well pool serves as the major heat sink for condensation of steam. The blowdown causes both dynamic and structural loads to the condensation pool. There might also be a risk that the gas discharging to the pool could push its way to the emergency core cooling systems (ECCS) and undermine their performance. (author)

Gas condensate--raw material for producing liquid paraffin hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Aliyeva, R.B.; Alikishi-Zade, G.Yu.; Kuliyev, A.M.; Leonidov, A.N.; Pereverzev, A.N.

1980-01-01

The problem of efficient utilization of gas condensates as raw material for removal of a valuable product, liquid paraffins, is examined. A classification of gas condensates is given which is used as raw material for removing these hydrocarbons: gas condensate with high content of n-alkanes (25-40 mass percent), with average content (18-25 mass percent), with low content (12-18 mass percent), light weight fractions compositions, which do not contain fractions up to 200/sup 0/, and also, content ofless than 12% n-alkanes. Gas condensate I-III groups are 30% of the total reserve of gas condensate. Liquid paraffins hydrocarbons, produced from fractions of diesel fuel, which has been removed from Shatlyk gas condensate under conditions which simulate virtual processes of caramide deparaffinization meet all requirements without additional refining.

Calcium ions function as a booster of chromosome condensation.

Science.gov (United States)

Phengchat, Rinyaporn; Takata, Hideaki; Morii, Kenichi; Inada, Noriko; Murakoshi, Hideji; Uchiyama, Susumu; Fukui, Kiichi

2016-12-02

Chromosome condensation is essential for the faithful transmission of genetic information to daughter cells during cell division. The depletion of chromosome scaffold proteins does not prevent chromosome condensation despite structural defects. This suggests that other factors contribute to condensation. Here we investigated the contribution of divalent cations, particularly Ca 2+ , to chromosome condensation in vitro and in vivo. Ca 2+ depletion caused defects in proper mitotic progression, particularly in chromosome condensation after the breakdown of the nuclear envelope. Fluorescence lifetime imaging microscopy-Förster resonance energy transfer and electron microscopy demonstrated that chromosome condensation is influenced by Ca 2+ . Chromosomes had compact globular structures when exposed to Ca 2+ and expanded fibrous structures without Ca 2+ . Therefore, we have clearly demonstrated a role for Ca 2+ in the compaction of chromatin fibres.

Influence of the distribution of non-condensables on passive containment condenser performance in PANDA

International Nuclear Information System (INIS)

Bandurski, Th.; Huggenberger, M.; Dreier, J.; Aubert, C.; Putz, F.; Gamble, R.E.; Yadigaroglu, G.

2001-01-01

Recently passive cooling systems have been designed for the long-term decay heat removal from the containment of Advanced Light Water Reactors. In particular, the long-term LOCA response of the Passive Containment Cooling System (PCCS) for the General Electric European Simplified Boiling Water Reactor (ESBWR) has been tested in the large-scale PANDA facility. The PANDA tests achieved the dual objectives of improving confidence in the performance of the passive heat removal mechanisms underlying the design of the system, and extending the database available for containment analysis code qualification. The tests conducted subject the PCCS to a variety of conditions representing design-basis and beyond-design-basis accident conditions. These include operation in the presence of both heavier and lighter than steam non-condensable gases, as well as a variety of asymmetric and challenging start-up conditions. The present paper addresses the transient distribution of non-condensables in PANDA, and their effect on (passive) condenser performance. (author)

Influence of the distribution of non-condensables on passive containment condenser performance in PANDA

Energy Technology Data Exchange (ETDEWEB)

Bandurski, Th.; Huggenberger, M.; Dreier, J.; Aubert, C.; Putz, F.; Gamble, R.E.; Yadigaroglu, G

2001-03-01

Recently passive cooling systems have been designed for the long-term decay heat removal from the containment of Advanced Light Water Reactors. In particular, the long-term LOCA response of the Passive Containment Cooling System (PCCS) for the General Electric European Simplified Boiling Water Reactor (ESBWR) has been tested in the large-scale PANDA facility. The PANDA tests achieved the dual objectives of improving confidence in the performance of the passive heat removal mechanisms underlying the design of the system, and extending the database available for containment analysis code qualification. The tests conducted subject the PCCS to a variety of conditions representing design-basis and beyond-design-basis accident conditions. These include operation in the presence of both heavier and lighter than steam non-condensable gases, as well as a variety of asymmetric and challenging start-up conditions. The present paper addresses the transient distribution of non-condensables in PANDA, and their effect on (passive) condenser performance. (author)

Vortices in a rotating dark matter condensate

International Nuclear Information System (INIS)

Yu, Rotha P; Morgan, Michael J

2002-01-01

We examine vortices in a self-gravitating dark matter Bose-Einstein condensate (BEC), consisting of ultra-low mass scalar bosons that arise during a late-time cosmological phase transition. Rotation of the dark matter BEC imprints a background phase gradient on the condensate, which establishes a harmonic trap potential for vortices. A numerical simulation of vortex dynamics shows that the vortex number density, n v ∝ r -1 , resulting in a flat velocity profile for the dark matter condensate. (letter to the editor)

Experimental Investigation of Flow Condensation in Microgravity

Science.gov (United States)

Lee, Hyoungsoon; Park, Ilchung; Konishi, Christopher; Mudawar, Issam; May, Rochelle I.; Juergens, Jeffery R.; Wagner, James D.; Hall, Nancy R.; Nahra, Henry K.; Hasan, Mohammed M.;

Chromosome condensation and radiation-induced G2 arrest studied by the induction of premature chromosome condensation following cell fusion

International Nuclear Information System (INIS)

Mitchell, J.B.; Bedford, J.S.

1978-01-01

When mitotic and interphase cells are fused together, the chromosomes of the interphase cell sometimes condense prematurely. The phenomenon of premature chromosome condensation (PCC) was utilized in investigating the problem of whether the chromosomes of cells suffering a radiation-induced G 2 delay are capable of condensation. Colcemide-arrested mitotic cells were fused with synchronized G 2 cells, and with irradiated cells suffering a G 2 delay. The frequency of PCC in mitotic X G 2 binucleate cells was determined. This was compared to the PCC frequency in an unirradiated synchronized population rich in G 2 cells after fusion with mitotic cells. Flash-labelling with 3 HTdR and autoradiography allowed S-phase cells to be eliminated. The frequency of G 2 PCCs was not significantly different for the irradiated G 2 -delayed or unirradiated cells. From these results it was concluded that the chromosomes of cells suffering a G 2 arrest are capable of condensation, although the involvement of the condensation process in radiation-induced G 2 delay could not be ruled out. (author)

Evaporation and Condensation Flows of a Vapor-Gas Mixture from or onto the Condensed Phase with an Internal Structure

National Research Council Canada - National Science Library

Onishi, Yoshimoto; Yamada, Ken

2005-01-01

Transient motions of a vapor-gas mixture due to the evaporation and condensation processes from or onto the plane condensed phase, with a temperature field as its internal structure, have been studied...

Water condensation on ultrahydrophobic flexible micro pillar surface

Science.gov (United States)

Narhe, Ramchandra

2016-05-01

We investigated the growth dynamics of water drops in controlled condensation on ultrahydrophobic geometrically patterned polydimethylsiloxane (PDMS) cylindrical micro pillars. At the beginning, the condensed drops size is comparable to the pattern dimensions. The interesting phenomenon we observe is that, as the condensation progresses, water drops between the pillars become unstable and enforced to grow in the upward direction along the pillars surface. The capillary force of these drops is of the order of μ\\text{N} and acts on neighboring pillars. That results into bending of the pillars. Pillars bending enhances the condensation and favors the most energetically stable Wenzel state.

The condensation of water on adsorbed viruses.

Science.gov (United States)

Alonso, José María; Tatti, Francesco; Chuvilin, Andrey; Mam, Keriya; Ondarçuhu, Thierry; Bittner, Alexander M

2013-11-26

The wetting and dewetting behavior of biological nanostructures and to a greater degree single molecules is not well-known even though their contact with water is the basis for all biology. Here, we show that environmental electron microscopy (EM) can be applied as a means of imaging the condensation of water onto viruses. We captured the formation of submicrometer water droplets and filaments on single viral particles by environmental EM and by environmental transmission EM. The condensate structures are compatible with capillary condensation between adsorbed virus particles and with known droplet shapes on patterned surfaces. Our results confirm that such droplets exist down to condensation/evaporation cycle as expected from their stability in air and water. Moreover we developed procedures that overcome problems of beam damage and of resolving structures with a low atomic number.

Spin polarized semimagnetic exciton-polariton condensate in magnetic field.

Science.gov (United States)

Król, Mateusz; Mirek, Rafał; Lekenta, Katarzyna; Rousset, Jean-Guy; Stephan, Daniel; Nawrocki, Michał; Matuszewski, Michał; Szczytko, Jacek; Pacuski, Wojciech; Piętka, Barbara

2018-04-27

Owing to their integer spin, exciton-polaritons in microcavities can be used for observation of non-equilibrium Bose-Einstein condensation in solid state. However, spin-related phenomena of such condensates are difficult to explore due to the relatively small Zeeman effect of standard semiconductor microcavity systems and the strong tendency to sustain an equal population of two spin components, which precludes the observation of condensates with a well defined spin projection along the axis of the system. The enhancement of the Zeeman splitting can be achieved by introducing magnetic ions to the quantum wells, and consequently forming semimagnetic polaritons. In this system, increasing magnetic field can induce polariton condensation at constant excitation power. Here we evidence the spin polarization of a semimagnetic polaritons condensate exhibiting a circularly polarized emission over 95% even in a moderate magnetic field of about 3 T. Furthermore, we show that unlike nonmagnetic polaritons, an increase on excitation power results in an increase of the semimagnetic polaritons condensate spin polarization. These properties open new possibilities for testing theoretically predicted phenomena of spin polarized condensate.

Review of steam jet condensation in a water pool

International Nuclear Information System (INIS)

Kim, Y. S.; Song, C. H.; Park, C. K.; Kang, H. S.; Jeon, H. G.; Yoon, Y. J.

2002-01-01

In the advanced nuclear power plants including APR1400, the SDVS is adopted to increase the plant safety using the concept of feed-and-bleed operation. In the case of the TLOFW, the POSRV located at the top of the pressurizer is expected to open due to the pressurization of the reactor coolant system and discharges steam and/or water mixture into the water pool, where the mixture is condensed. During the condensation of the mixture, thermal-hydraulic loads such as pressure and temperature variations are induced to the pool structure. For the pool structure design, such thermal-hydraulic aspects should be considered. Understanding the phenomena of the submerged steam jet condensation in a water pool is helpful for system designers to design proper pool structure, sparger, and supports etc. This paper reviews and evaluates the steam jet condensation in a water pool on the physical phenomena of the steam condensation including condensation regime map, heat transfer coefficient, steam plume, steam jet condensation load, and steam jet induced flow

ANÁLISE CLÍNICA E HISTOLÓGICA DA UTILIZAÇÃO DA RESINA ACRÍLICA AUTOPOLIMERIZÁVEL NAS FRATURAS DE MANDÍBULA E MAXILA E SEPARAÇÃO DA SÍNFISE MENTONIANA EM CÃES E GATOS CLINICAL AND HISTOLOGICAL EVALUATION OF ACRYLIC RESIN IN THE FRACTURE OF THE MANDIBLE AND MAXILLA AND SEPARATION OF MANDIBULAR SYMPHISIS IN DOGS AND CATS

Directory of Open Access Journals (Sweden)

Marco Antonio Gioso

2001-04-01

Full Text Available O trabalho foi desenvolvido em duas fases. A primeira constou de aplicação de resina acrílica autopolimerizável sobre dentes de cães experimentais, sem condicionamento ácido do esmalte dental; a gengiva foi analisada histologicamente nos períodos de um, três, sete, 14, 21 e 30 dias. A segunda fase foi conduzida em 20 cães e 10 gatos com fraturas do sistema estomatognático, atendidos no Ambulatório Central da FMVZ/USP. Nessa segunda fase, clínica, foi aplicado condicionamento ácido do esmalte. A resina era usada nas fraturas rostrais às raízes distais do primeiro molar inferior e do quarto pré-molar superior, bem como na separação da sínfise mentoniana. Os resultados da primeira fase mostraram que mesmo sem o condicionamento ácido houve aderência da resina acrílica sobre os dentes, embora houvesse necessidade de maior volume do material, o que provocou ulcerações dos tecidos moles da boca. Essa fase também evidenciou, à sondagem, que o epitélio de aderência sulcular permaneceu aderido, além de gengivite, ulceração da gengiva, língua e mucosa alveolar. A análise histológica revelou predominantemente ulceração dos tecidos em contato com a resina. Na segunda fase, todos os animais evidenciaram consolidação óssea das fraturas, além de gengivite e ulceração. Lesões periodontais foram encontradas em dois animais dos quais a resina foi removida tardiamente, com quatro e 12 meses após a aplicação, respectivamente. Em ambas as fases, os animais adaptaram-se bem à resina sobre os dentes.This paper was performed in two phases. In the first one, the stability of the acrylic resin over the teeth of dogs, without enamel acid conditioning, the clinical and histological reaction on the gingiva were analyzed in periods of 1, 3, 7, 14, 21 and 30 days. The second phase was conducted in 20 dogs and 10 cats, with acid etching technique. The resin was used in the rostral fractures to the distal roots of the lower first

On inflation in the presence of a gaugino condensate

International Nuclear Information System (INIS)

Lebedev, Oleg; Papineau, Chloe

2009-07-01

We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe. (orig.)

On inflation in the presence of a gaugino condensate

International Nuclear Information System (INIS)

Lebedev, Oleg; Papineau, Chloe; Postma, Marieke

2010-01-01

We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model-independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe.

On inflation in the presence of a gaugino condensate

Energy Technology Data Exchange (ETDEWEB)

Lebedev, Oleg; Papineau, Chloe [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Postma, Marieke [NIKHEF, Amsterdam (Netherlands)

2009-07-15

We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe. (orig.)

On inflation in the presence of a gaugino condensate

Energy Technology Data Exchange (ETDEWEB)

Lebedev, Oleg [DESY Theory Group, Notkestrasse 85, D-22607 Hamburg (Germany); Papineau, Chloe, E-mail: chloe.papineau@desy.d [DESY Theory Group, Notkestrasse 85, D-22607 Hamburg (Germany); Postma, Marieke [NIKHEF, Kruislaan 409, 1098 Amsterdam (Netherlands)

2010-02-08

We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model-independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe.

A transport-based condensed history algorithm

International Nuclear Information System (INIS)

Tolar, D. R. Jr.

1999-01-01

Condensed history algorithms are approximate electron transport Monte Carlo methods in which the cumulative effects of multiple collisions are modeled in a single step of (user-specified) path length s 0 . This path length is the distance each Monte Carlo electron travels between collisions. Current condensed history techniques utilize a splitting routine over the range 0 le s le s 0 . For example, the PEnELOPE method splits each step into two substeps; one with length ξs 0 and one with length (1 minusξ)s 0 , where ξ is a random number from 0 0 is fixed (not sampled from an exponential distribution), conventional condensed history schemes are not transport processes. Here the authors describe a new condensed history algorithm that is a transport process. The method simulates a transport equation that approximates the exact Boltzmann equation. The new transport equation has a larger mean free path than, and preserves two angular moments of, the Boltzmann equation. Thus, the new process is solved more efficiently by Monte Carlo, and it conserves both particles and scattering power

Scattering of atoms on a Bose-Einstein condensate

International Nuclear Information System (INIS)

Poulsen, Uffe V.; Moelmer, Klaus

2003-01-01

We study the scattering properties of a Bose-Einstein condensate held in a finite depth well when the incoming particles are identical to the ones in the condensate. We calculate phase shifts and corresponding transmission and reflection coefficients, and we show that the transmission times can be negative, i.e., the atomic wave packet seemingly leaves the condensate before it arrives

Capillary Condensation in Confined Media

OpenAIRE

Charlaix, Elisabeth; Ciccotti, Matteo

2009-01-01

28 pages - To appear in 2010 in the Handbook of Nanophysics - Vol 1 - Edited by Klaus Sattler - CRC Press; We review here the physics of capillary condensation of liquids in confined media, with a special regard to the application in nanotechnologies. The thermodynamics of capillary condensation and thin film adsorption are first exposed along with all the relevant notions. The focus is then shifted to the modelling of capillary forces, to their measurements techniques (including SFA, AFM and...

Capillary condensation between disks in two dimensions

DEFF Research Database (Denmark)

Gil, Tamir; Ipsen, John Hjorth

1997-01-01

Capillary condensation between two two-dimensional wetted circular substrates (disks) is studied by an effective free energy description of the wetting interface. The interfacial free-energy potential is developed on the basis of the theory for the wetting of a single disk, where interfacial...... capillary fluctuations play a dominant role. A simple approximative analytical expression of the interfacial free energy is developed and is validated numerically. The capillary condensation is characterized by the analysis of the coverage of the condensed phase, its stability, and asymptotic behaviors...

Dropwise condensation on inclined textured surfaces

CERN Document Server

Khandekar, Sameer

2014-01-01

Dropwise Condensation on Textured Surfaces presents a holistic framework for understanding dropwise condensation through mathematical modeling and meaningful experiments. The book presents a review of the subject required to build up models as well as to design experiments. Emphasis is placed on the effect of physical and chemical texturing and their effect on the bulk transport phenomena. Application of the model to metal vapor condensation is of special interest. The unique behavior of liquid metals, with their low Prandtl number and high surface tension, is also discussed. The model predicts instantaneous drop size distribution for a given level of substrate subcooling and derives local as well as spatio-temporally averaged heat transfer rates and wall shear stress.

Cytoskeletal Reorganization Drives Mesenchymal Condensation and Regulates Downstream Molecular Signaling.

Directory of Open Access Journals (Sweden)

Poulomi Ray

Full Text Available Skeletal condensation occurs when specified mesenchyme cells self-organize over several days to form a distinctive cartilage template. Here, we determine how and when specified mesenchyme cells integrate mechanical and molecular information from their environment, forming cartilage condensations in the pharyngeal arches of chick embryos. By disrupting cytoskeletal reorganization, we demonstrate that dynamic cell shape changes drive condensation and modulate the response of the condensing cells to Fibroblast Growth Factor (FGF, Bone Morphogenetic Protein (BMP and Transforming Growth Factor beta (TGF-β signaling pathways. Rho Kinase (ROCK-driven actomyosin contractions and Myosin II-generated differential cell cortex tension regulate these cell shape changes. Disruption of the condensation process inhibits the differentiation of the mesenchyme cells into chondrocytes, demonstrating that condensation regulates the fate of the mesenchyme cells. We also find that dorsal and ventral condensations undergo distinct cell shape changes. BMP signaling is instructive for dorsal condensation-specific cell shape changes. Moreover, condensations exhibit ventral characteristics in the absence of BMP signaling, suggesting that in the pharyngeal arches ventral morphology is the ground pattern. Overall, this study characterizes the interplay between cytoskeletal dynamics and molecular signaling in a self-organizing system during tissue morphogenesis.

Studies of condensation/evaporation processes in the Glowworm Cave, New Zealand

Directory of Open Access Journals (Sweden)

de Freitas Chris R.

2006-07-01

Full Text Available The condensation/evaporation process is important in caves, especially in tourist caves where there is carbon dioxide enriched air caused by visitors. The cycle of condensation and evaporation of condensate is believed to enhance condensation corrosion. The problem is condensation is difficult to measure. This study addresses the problem and reports on a method for measuring and modelling condensation rates in a limestone cave. Electronic sensors for measuring condensation and evaporation of the condensate as part of a single continuous process of water vapour flux are tested and used to collect 12 months of data. The study site is the Glowworm tourist cave in New Zealand. The work describes an explanatory model of processes leading to condensation using data based on measurements of condensation and evaporation as part of a single continuous process of water vapour flux. The results show that the model works well. However, one of the most important messages from the research reported here is the introduction of the condensation sensor. The results show that condensation in caves can actually be measured and monitored, virtually in real time. In conjunction with the recent developments in data logging equipment, this opens exciting perspectives in cave climate studies, and, more generally, in hydrogeological studies in karst terrains.

Soliton resonance in bose-einstein condensate

Science.gov (United States)

Zak, Michail; Kulikov, I.

2002-01-01

A new phenomenon in nonlinear dispersive systems, including a Bose-Einstein Condensate (BEC), has been described. It is based upon a resonance between an externally induced soliton and 'eigen-solitons' of the homogeneous cubic Schrodinger equation. There have been shown that a moving source of positive /negative potential induces bright /dark solitons in an attractive / repulsive Bose condensate.

Bose condensation in 4He and neutron scattering

International Nuclear Information System (INIS)

Silver, R.N.

1997-01-01

The discovery of superfluidity in liquid 4 He below T λ = 2.17 K, and its phenomenological characterization since then, has been one of the great success stories of condensed matter physics. The relation of superfluidity to the behavior of atoms was conjectured by F. London in 1938. Superfluidity is a manifestation of the Bose condensation of helium atoms, the extensive occupation of the zero momentum state. Ever since 4 He has been the paradigm in the search for Bose condensates in other systems. At the Pune meeting scientists have heard exciting new evidence for Bose condensates of laser cooled alkali atoms in magnetic traps, of excitons in Cu 2 O, and possibly pre-formed Cooper pairs of electrons in the high T c perovskite superconductors. There remains the holy-grail of forming a Bose condensate in spin-polarized hydrogen. In the current excitement for new types of Bose condensates, and new phenomena such as atom lasers, it may be useful to recall the older story of the experimental verification of a relation between superfluidity and Bose condensation in 4 He. This topic has been investigated over many years by neutron scattering experiments and quantum many-body theory. The authors goal is to illustrate the difficulties of establishing the existence of a Bose condensate in a strongly interacting system, even though its macroscopic effects are manifest. The author assumes readers have access to a review by Silver and Sokol which emphasizes the neutron scattering theory through 1990 and a review by Snow and Sokol of the deep inelastic neutron scattering (DINS) experiments through 1995

Bose-Einstein condensation in atomic alkali gases

Science.gov (United States)

Dodd, Robert J.

1998-05-01

I present a review of the time-independent Gross-Pitaevskii (GP), Bogoliubov, and finite-temperature Hartree-Fock-Bogoliubov (HFB) mean-field theories used to study trapped, Bose-Einstein condensed alkali gases. Numerical solutions of the (zero-temperature) GP equation are presented for attractive (negative scattering length) and repulsive (positive scattering length) interactions. Comparison is made with the Thomas-Fermi and (variational) trial wavefunction appr oximations that are used in the literature to study condensed gases. Numerical calculations of the (zero-temperature) Bogoliubov quasi-particle excitation frequencies are found to be in excellent agreement with the experimental results. The finite-temperature properties of condensed gases are examined using the Popov approximation (of the HFB theory) and a simple two-gas model. Specific, quantitative comparisons are made with experimental results for finite-temperature excitation frequencies. Qualitative comparisons are made between the results of the Popov approximation, two-gas model, and other published models for condensate fraction and thermal density distribution. The time-independent mean-field theories are found to be in excellent agreement with experimental results at relatively low temperatures (high condensate fractions). However, at higher temperatures (and condensate fractions of less than 50%) there are significant discrepancies between experimental data and theoretical calculations. This work was undertaken at the University of Maryland at College Park and was supported in part by the National Science Foundation (PHY-9601261) and the U.S. Office of Naval Research.

Some concepts in condensed phase chemical kinetics

International Nuclear Information System (INIS)

Adelman, S.A.

1986-01-01

Some concepts in condensed phase chemical kinetics which have emerged from a recent rigorous statistical mechanical treatment of condensed phase chemical reaction dynamics (S.A. Adelman, Adv. Chem. Phys.53:61 (1983)) are discussed in simple physical terms

Dropwise condensation on hydrophobic bumps and dimples

Science.gov (United States)

Yao, Yuehan; Aizenberg, Joanna; Park, Kyoo-Chul

2018-04-01

Surface topography plays an important role in promoting or suppressing localized condensation. In this work, we study the growth of water droplets on hydrophobic convex surface textures such as bumps and concave surface textures such as dimples with a millimeter scale radius of curvature. We analyze the spatio-temporal droplet size distribution under a supersaturation condition created by keeping the uniform surface temperature below the dew point and show its relationship with the sign and magnitude of the surface curvature. In particular, in contrast to the well-known capillary condensation effect, we report an unexpectedly less favorable condensation on smaller, millimeter-scale dimples where the capillary condensation effect is negligible. To explain these experimental results, we numerically calculated the diffusion flux of water vapor around the surface textures, showing that its magnitude is higher on bumps and lower on dimples compared to a flat surface. We envision that our understanding of millimetric surface topography can be applied to improve the energy efficiency of condensation in applications such as water harvesting, heating, ventilation, and air conditioning systems for buildings and transportation, heat exchangers, thermal desalination plants, and fuel processing systems.

Diagnosis of condensation-induced waterhammer: Case studies

International Nuclear Information System (INIS)

Izenson, M.G.; Rothe, P.H.; Wallis, G.B.

1988-10-01

This guidebook provides reference material and diagnostic procedures concerning condensation-induced waterhammer in nuclear power plants. Condensation-induced waterhammer is the most damaging form of waterhammer, and its diagnosis is complicated by the complex nature of the underlying phenomena. In Volume 1, the guidebook groups condensation-induced waterhammers into five event classes which have similar phenomena and levels of damage. Diagnostic guidelines focus on locating the event center where condensation and slug acceleration take place. Diagnosis is described in three stages: an initial assessment, detailed evaluation and final confirmation. Graphical scoping analyses are provided to evaluate whether an event from one of the event classes could have occurred at the event center. Examples are provided for each type of waterhammer. Special instructions are provided for walking down damaged piping and evaluating damage due to waterhammer. To illustrate the diagnostic methods and document past experience, six case studies have been compiled in Volume 2. These case studies, based on actual condensation-induced waterhammer events at nuclear plants, present detailed data and work through the event diagnosis using the tools introduced in the first volume. 20 refs., 21 figs., 6 tabs

Energy condensed packaged systems. Composition, production, properties

Directory of Open Access Journals (Sweden)

Igor L. Kovalenko

2015-03-01

Full Text Available In this paper it is presented the substantiation of choice of fuel phase composition and optimal technology of emulsion production on the basis of binary solution of ammonium and calcium nitrates, which provide the obtaining of energy condensed packaged systems with specified properties. The thermal decomposition of energy condensed systems on the basis of ammonium nitrate is investigated. It is shown that the fuel phase of emulsion systems should be based on esters of polyunsaturated acids or on combinations thereof with petroleum products. And ceresin or petroleum wax can be used as the structuring additive. The influence of the technology of energy condensed systems production on the physicochemical and detonation parameters of emulsion explosives is considered. It is shown the possibility of obtaining of emulsion systems with dispersion of 1.3...1.8 microns and viscosity higher than 103 Pa∙s in the apparatus of original design. The sensitizing effect of chlorinated paraffin CP-470 on the thermolysis of energy condensed emulsion system is shown. The composition and production technology of energy condensed packaged emulsion systems of mark Ukrainit-P for underground mining in mines not dangerous on gas and dust are developed.

Design of spiral fin type condenser for hydrogen cryogenic distillation column

International Nuclear Information System (INIS)

Iwai, Yasunori; Nishi, Masataka; Yamanishi, Toshihiko

2005-08-01

The purpose of this paper is the proposal of new concept condenser for hydrogen cryogenic distillation column of Hydrogen Isotope Separation System (ISS) in a fusion reactor, and the establishment of numerical evaluation method of the hydrogen isotope inventory in the condenser. A large amount of hydrogen isotopes including high concentration of tritium, radioactive hydrogen isotope, has been handled in the cryogenic distillation column. Therefore, from the safety point of view, cryogenic coolant tube was commonly arranged to surround the condensed area to prevent the mixing of tritium into the coolant. This inevitable arrangement leads the difficulty in the minimization of the condenser. The scale of condenser has influence on the scale of the ISS and its earthquake-resistance. The spiral fin type condenser, which introduces fins inside it and in coolant tube to enhance heat exchange, is proposed as a new concept condenser for hydrogen cryogenic distillation column to miniaturize the condenser. The volume of spiral fin type condenser is estimated to become less than half of that of coil tube type condenser currently in use. Accordingly, it is found that the adoption of spiral fin type condenser realizes the significant miniaturization of the ISS. Moreover, the numerical evaluation method of the hydrogen isotope inventory in the condenser is proposed. The validity of this method was confirmed by the experimental data. The synthetic design of the condenser for the hydrogen cryogenic distillation column is achieved by the combination of the proposed new concept condenser with the numerical evaluation method of the hydrogen isotope inventory. (author)

Containment condensing heat transfer

International Nuclear Information System (INIS)

Gido, R.G.; Koestel, A.

1983-01-01

This report presents a mechanistic heat-transfer model that is valid for large scale containment heat sinks. The model development is based on the determination that the condensation is controlled by mass diffusion through the vapor-air boundary layer, and the application of the classic Reynolds' analogy to formulate expressions for the transfer of heat and mass based on hydrodynamic measurements of the momentum transfer. As a result, the analysis depends on the quantification of the shear stress (momentum transfer) at the interface between the condensate film and the vapor-air boundary layer. In addition, the currently used Tagami and Uchida test observations and their range of applicability are explained

Experimental study of condensate subcooling with the use of a model of an air-cooled condenser

Science.gov (United States)

Sukhanov, V. A.; Bezukhov, A. P.; Bogov, I. A.; Dontsov, N. Y.; Volkovitsky, I. D.; Tolmachev, V. V.

2016-01-01

Water-supply deficit is now felt in many regions of the world. This hampers the construction of new steam-turbine and combined steam-and-gas thermal power plants. The use of dry cooling systems and, specifically, steam-turbine air-cooled condensers (ACCs) expands the choice of sites for the construction of such power plants. The significance of condensate subcooling Δ t as a parameter that negatively affects the engineering and economic performance of steam-turbine plants is thereby increased. The operation and design factors that influence the condensate subcooling in ACCs are revealed, and the research objective is, thus, formulated properly. The indicated research was conducted through physical modeling with the use of the Steam-Turbine Air-Cooled Condenser Unit specialized, multipurpose, laboratory bench. The design and the combined schematic and measurement diagram of this test bench are discussed. The experimental results are presented in the form of graphic dependences of the condensate subcooling value on cooling ratio m and relative weight content ɛ' of air in steam at the ACC inlet at different temperatures of cooling air t ca ' . The typical ranges of condensate subcooling variation (4 ≤ Δ t ≤ 6°C, 2 ≤ Δ t ≤ 4°C, and 0 ≤ Δ t ≤ 2°C) are identified based on the results of analysis of the attained Δ t levels in the ACC and numerous Δ t reduction estimates. The corresponding ranges of cooling ratio variation at different temperatures of cooling air at the ACC inlet are specified. The guidelines for choosing the adjusted ranges of cooling ratio variation with account of the results of experimental studies of the dependences of the absolute pressure of the steam-air mixture in the top header of the ACC and the heat flux density on the cooling ratio at different temperatures of cooling air at the ACC inlet are given.

Modeling the Phase Composition of Gas Condensate in Pipelines

Science.gov (United States)

Dudin, S. M.; Zemenkov, Yu D.; Shabarov, A. B.

2016-10-01

Gas condensate fields demonstrate a number of thermodynamic characteristics to be considered when they are developed, as well as when gas condensate is transported and processed. A complicated phase behavior of the gas condensate system, as well as the dependence of the extracted raw materials on the phase state of the deposit other conditions being equal, is a key aspect. Therefore, when designing gas condensate lines the crucial task is to select the most appropriate methods of calculating thermophysical properties and phase equilibrium of the transported gas condensate. The paper describes a physical-mathematical model of a gas-liquid flow in the gas condensate line. It was developed based on balance equations of conservation of mass, impulse and energy of the transported medium within the framework of a quasi-1D approach. Constitutive relationships are given separately, and practical recommendations on how to apply the research results are provided as well.

Steam condensation modelling in aerosol codes

International Nuclear Information System (INIS)

Dunbar, I.H.

1986-01-01

The principal subject of this study is the modelling of the condensation of steam into and evaporation of water from aerosol particles. These processes introduce a new type of term into the equation for the development of the aerosol particle size distribution. This new term faces the code developer with three major problems: the physical modelling of the condensation/evaporation process, the discretisation of the new term and the separate accounting for the masses of the water and of the other components. This study has considered four codes which model the condensation of steam into and its evaporation from aerosol particles: AEROSYM-M (UK), AEROSOLS/B1 (France), NAUA (Federal Republic of Germany) and CONTAIN (USA). The modelling in the codes has been addressed under three headings. These are the physical modelling of condensation, the mathematics of the discretisation of the equations, and the methods for modelling the separate behaviour of different chemical components of the aerosol. The codes are least advanced in area of solute effect modelling. At present only AEROSOLS/B1 includes the effect. The effect is greater for more concentrated solutions. Codes without the effect will be more in error (underestimating the total airborne mass) the less condensation they predict. Data are needed on the water vapour pressure above concentrated solutions of the substances of interest (especially CsOH and CsI) if the extent to which aerosols retain water under superheated conditions is to be modelled. 15 refs

Model of a chromomagnetic condensate in QCD

International Nuclear Information System (INIS)

Vladimirsky, V.V.

1996-01-01

The simplest form of the effective Lagrangian of a gluon field leads to a deep degeneracy of a magnetic condensate that arises when the stability of the standard perturbative vacuum is violated by quantum effects. The inclusion of terms in the effective Lagrangian that conserve color and Lorentz invariance enables the possible types of Abelian and non-Abelian condensate fields to be classified. The degeneracy is partially removed. One of the four types of the condensate permits the emergence of closed vortex lines that correspond to cyclic permutations of colors upon circumventions around stringlike singularities

Finite-momentum condensation in a pumped microcavity

International Nuclear Information System (INIS)

Brierley, R. T.; Eastham, P. R.

2010-01-01

We calculate the absorption spectra of a semiconductor microcavity into which a nonequilibrium exciton population has been pumped. We predict strong peaks in the spectrum corresponding to collective modes analogous to the Cooper modes in superconductors and fermionic atomic gases. These modes can become unstable, leading to the formation of off-equilibrium quantum condensates. We calculate a phase diagram for condensation and show that the dominant instabilities can be at a finite momentum. Thus we predict the formation of inhomogeneous condensates, similar to Fulde-Ferrel-Larkin-Ovchinnikov states.

Capillary condensation of adsorbates in porous materials.

Science.gov (United States)

Horikawa, Toshihide; Do, D D; Nicholson, D

2011-11-14

Hysteresis in capillary condensation is important for the fundamental study and application of porous materials, and yet experiments on porous materials are sometimes difficult to interpret because of the many interactions and complex solid structures involved in the condensation and evaporation processes. Here we make an overview of the significant progress in understanding capillary condensation and hysteresis phenomena in mesopores that have followed from experiment and simulation applied to highly ordered mesoporous materials such as MCM-41 and SBA-15 over the last few decades. Copyright © 2011 Elsevier B.V. All rights reserved.

Optimisation of condenser design in waste immobilisation plants (WIP`s)

Energy Technology Data Exchange (ETDEWEB)

Rajani, G; Ozarde, P D; Gandhi, P M [Waste Management Projects Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

The situation under study is vertical heat exchanger with steam as the condensing vapour and NO{sub x} gases as the non condensible gas. The presence of even a small quantity of non-condensible gas in the condensible vapour has a profound influence on the resistance to heat transfer in the region of liquid-vapour heat transfer. Heat transfer coefficients go on reducing progressively, making condensers prohibitively bulky and hence optimisation of condensers is necessary for carrying out design calculations. The condenser has been divided into segments and for each segment, momentum and energy equations have been established and solved. Finally the average value for overall mass transfer coefficients has been calculated. Parametric studies giving the influence of sub cooling gases, water temperature, exit temperature etc. have been studied. (author). 5 refs., 5 figs., 2 tabs.

A macrothermodynamic approach to the limit of reversible capillary condensation.

Science.gov (United States)

Trens, Philippe; Tanchoux, Nathalie; Galarneau, Anne; Brunel, Daniel; Fubini, Bice; Garrone, Edoardo; Fajula, François; Di Renzo, Francesco

2005-08-30

The threshold of reversible capillary condensation is a well-defined thermodynamic property, as evidenced by corresponding states treatment of literature and experimental data on the lowest closure point of the hysteresis loop in capillary condensation-evaporation cycles for several adsorbates. The nonhysteretical filling of small mesopores presents the properties of a first-order phase transition, confirming that the limit of condensation reversibility does not coincide with the pore critical point. The enthalpy of reversible capillary condensation can be calculated by a Clausius-Clapeyron approach and is consistently larger than the condensation heat in unconfined conditions. Calorimetric data on the capillary condensation of tert-butyl alcohol in MCM-41 silica confirm a 20% increase of condensation heat in small mesopores. This enthalpic advantage makes easier the overcoming of the adhesion forces by the capillary forces and justifies the disappearing of the hysteresis loop.

Interesantes aplicaciones de las resinas sintéticas en obras de ingeniería civil

Directory of Open Access Journals (Sweden)

Vié, G.

1970-12-01

Full Text Available The author describes the growing importance of epoxy resins in construction, especially in public works. A brief account is given of the physical and chemical properties, such as almost total resistance to chemical action; high anticorrosive strength; better mechanical strength than concrete; insensibility to icing-deicing cycles and thermal changes; high bond with most materials; no changes due to ageing; great resistance to wearing and abrasive actions; good aspect; high electrical resistance; and others. The article also describes some of its most common uses, including fillings, injections, fixings, industrial floorings, tunnel facing, and waterproofing of cracks. Examples of some recent uses in France are also cited.El autor describe la importancia creciente que han adquirido las resinas epoxi en la construcción y, particularmente, en las obras públicas. Hace una exposición sucinta de sus propiedades físicas y químicas más destacadas: resistencia química prácticamente total, poder anticorrosivo elevado, mejores características mecánicas que el hormigón, insensibilidad a los ciclos hielo-deshielo y a las variaciones térmicas, poder adhesivo notable para todos los materiales, ninguna modificación por envejecimiento, gran resistencia al desgaste y a la abrasión, efecto decorativo, y gran resistividad eléctrica; así como de las utilizaciones más usuales: recrecidos, inyecciones, empotramientos, suelos industriales, revestimientos en túneles, impermeabilización de fisuras, etc. Se añaden algunos ejemplos recientes de su empleo en Francia.

Bose-Einstein Condensation

Indian Academy of Sciences (India)

absolute zero. These ideas had ... Everybody is talking about Bose-Einstein condensation. This discovery ... needed if we want to find the probability distribution of the x- ... Boltzmann took two approaches to the problem, both of them deep and ...

Enhancement of Condensation Heat Transfer Rate of the Air-Steam Mixture on a Passive Condenser System Using Annular Fins

Directory of Open Access Journals (Sweden)

Yeong-Jun Jang

2017-11-01

Full Text Available This paper presents an experimental investigation on the enhancement of the heat transfer rate of steam condensation on the external surfaces of a vertical tube with annular fins. A cylindrical condenser tube, which is 40 mm in outer diameter and 1000 mm in length, with annular disks of uniform cross-sectional area is fabricated in the manner of ensuring perfect contact between the base surface and fins. A total of 13 annular fins of 80 mm diameter were installed along the tube height in order to increase the effective heat transfer area by 85%. Through a series of condensation tests for the air-steam mixture under natural convection conditions, the heat transfer data was measured in the pressure range of between 2 and 5 bar, and the air mass fraction from 0.3 to 0.7. The rates of heat transfer of the finned tube are compared to those that are measured on a bare tube to demonstrate the enhanced performance by extended surfaces. In addition, based on the experimental results and the characteristics of steam condensation, the applicability of finned tubes to a large condenser system with a bundle layout is evaluated.

40 CFR 405.110 - Applicability; description of the condensed whey subcategory.

Science.gov (United States)

2010-07-01

... condensed whey subcategory. 405.110 Section 405.110 Protection of Environment ENVIRONMENTAL PROTECTION... Condensed Whey Subcategory § 405.110 Applicability; description of the condensed whey subcategory. The... whey and condensed acid whey. ...

Suppression/reducing method for total organic carbon in feedwater/condensate

International Nuclear Information System (INIS)

Maeda, Katsuharu.

1993-01-01

The present invention suppresses/reduces the concentration of the total organic carbon before the startup of a reactor, to decrease (TOC) which is brought into the reactor upon startup of the operation and suppress/moderate degradation of water quality of reactor water. That is, in-service period of a condensate desalting tower is shortened, to avoid concentration increase of TOC in feed water/condensate which is leached out from the condensate desalting tower. The condensate desalting towers are put to in-service for the entire towers after increasing the vacuum degree of the condensator, to suppress leaching of TOC from the condensate desalting tower. Further, upon startup of a nuclear power plant, when the condensate desalting tower is put to in-service, condensate filters of the entire towers are previously back-washed and regenerated to remove TOC efficiently. By these procedures, TOC brought from a water supply system upon startup of the plant is thermally decomposed or radiolyzed in the reactor, thereby enabling to suppress/avoid worsening of water quality of reactor water caused by generated ion impurities. (I.S.)

Introduction. Cosmology meets condensed matter.

Science.gov (United States)

Kibble, T W B; Pickett, G R

2008-08-28

At first sight, low-temperature condensed-matter physics and early Universe cosmology seem worlds apart. Yet, in the last few years a remarkable synergy has developed between the two. It has emerged that, in terms of their mathematical description, there are surprisingly close parallels between them. This interplay has been the subject of a very successful European Science Foundation (ESF) programme entitled COSLAB ('Cosmology in the Laboratory') that ran from 2001 to 2006, itself built on an earlier ESF network called TOPDEF ('Topological Defects: Non-equilibrium Field Theory in Particle Physics, Condensed Matter and Cosmology'). The articles presented in this issue of Philosophical Transactions A are based on talks given at the Royal Society Discussion Meeting 'Cosmology meets condensed matter', held on 28 and 29 January 2008. Many of the speakers had participated earlier in the COSLAB programme, but the strength of the field is illustrated by the presence also of quite a few new participants.

Theory of laminar film condensation

CERN Document Server

Fujii, Tetsu

1991-01-01

Since the petroleum crisis in the 1970s, a lot of effort to save energy was made in industry, and remarkable achievements have been made. In the research and development concerning thermal energy, however, it was clar­ ified that one of the most important problems was manufacturing con­ densing systems with smaller size and higher performance. To solve this problem we need a method which synthesizes selections_ of the type of con­ denser, cooling tube and its arrangement, assessment of fouling on the cooling surfaces, consideration of transient characteristics of a condenser, etc. The majority of effort, however, has been to devise a surface element which enhances the heat transfer coefficient in condensation of a single or multicomponent vapor. Condensation phenomena are complexly affected by a lot of physical property values, and accordingly the results of theo­ retical research are expressed with several dimensionless parameters. On the other hand, the experimental research is limited to those with som...

A Robust, Gravity-Insensitive, High-Temperature Condenser for Water Recovery

Science.gov (United States)

Chen, Weibo; Conboy, Thomas; Ewert, Michael

2016-01-01

Regenerative life support systems are vital for NASA's future long-duration human space exploration missions. A Heat Melt Compactor (HMC) system is being developed by NASA to dry and compress trash generated during space missions. The resulting water vapor is recovered and separated from the process gas flow by a gravity-insensitive condenser. Creare is developing a high-temperature condenser for this application. The entire condenser is constructed from metals that have excellent resistance to chemical attack from contaminants and is suitable for high-temperature operation. The metal construction and design configuration also offer greatest flexibility for potential coating and regeneration processes to reduce biofilm growth and thus enhancing the reliability of the condenser. The proposed condenser builds on the gravity-insensitive phase separator technology Creare developed for aircraft and spacecraft applications. This paper will first discuss the design requirements for the condenser in an HMC system that will be demonstrated on the International Space Station (ISS). Then, it will present the overall design of the condenser and the preliminary thermal test results of a subscale condenser. Finally, this paper will discuss the predicted performance of the full-size condenser and the development plan to mature the technology and enhance its long-term reliability for a flight system.

Condensed State Spaces for Symmetrical Coloured Petri Nets

DEFF Research Database (Denmark)

Jensen, Kurt

1996-01-01

equivalence classes of states and equivalence classes of state changes. It is then possible to construct a condensed state space where each node represents an equivalence class of states while each arc represents an equivalence class of state changes. Such a condensed state space is often much smaller than...... the full state space and it is also much faster to construct. Nevertheless, it is possible to use the condensed state space to verify the same kind of behavioural properties as the full state space. Hence, we do not lose analytic power. We define state spaces and condensed state spaces for a language......-nets (or Petri nets in general) - although such knowledge will, of course, be a help. The first four sections of the paper introduce the basic concepts of CP-nets. The next three sections deal with state spaces, condensed state spaces and computer tools for state space analysis. Finally, there is a short...

CFD simulation on condensation inside a Hybrid SIT

Energy Technology Data Exchange (ETDEWEB)

Jeon, Byong Guk; Ryu, Sung Uk; Kim, Seok; Euh, Dong Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2016-10-15

The concept of Hybrid Safety Injection Tank system (Hybrid SIT) was proposed by Korea Atomic Energy Research Institute (KAERI) aiming at Advanced Power Reactor Plus. The main advantage of the system is the ready injection of coolant into the reactor coolant system at high pressure. In this paper, a CFD simulation is conducted as a preliminary study. In Hybrid SITs, condensation inside the tank affects its pressure rise and injection time. In an attempt to explore the condensation in detail, we manufactured a dedicated experimental facility for visualization of condensation-induced thermal mixing and conducted a preliminary CFD simulation. Its condensation models were validated first and then computational domain was constructed. The water region was modeled as a solid for stable calculation. The CFD results gave less condensation and excessive pressurization because of lack of steam penetration into the water. In the future, the water region will be modeled as liquid using a VOF model.

Atom loss resonances in a Bose-Einstein condensate.

Science.gov (United States)

Langmack, Christian; Smith, D Hudson; Braaten, Eric

2013-07-12

Atom loss resonances in ultracold trapped atoms have been observed at scattering lengths near atom-dimer resonances, at which Efimov trimers cross the atom-dimer threshold, and near two-dimer resonances, at which universal tetramers cross the dimer-dimer threshold. We propose a new mechanism for these loss resonances in a Bose-Einstein condensate of atoms. As the scattering length is ramped to the large final value at which the atom loss rate is measured, the time-dependent scattering length generates a small condensate of shallow dimers coherently from the atom condensate. The coexisting atom and dimer condensates can be described by a low-energy effective field theory with universal coefficients that are determined by matching exact results from few-body physics. The classical field equations for the atom and dimer condensates predict narrow enhancements in the atom loss rate near atom-dimer resonances and near two-dimer resonances due to inelastic dimer collisions.

Temperature dependence of the coherence in polariton condensates

Science.gov (United States)

Rozas, E.; Martín, M. D.; Tejedor, C.; Viña, L.; Deligeorgis, G.; Hatzopoulos, Z.; Savvidis, P. G.

2018-02-01

We present a time-resolved experimental study of the temperature effect on the coherence of traveling polariton condensates. The simultaneous detection of their emission both in real and reciprocal space allows us to fully monitor the condensates' dynamics. We obtain fringes in reciprocal space as a result of the interference between polariton wave packets (WPs) traveling with the same speed. The periodicity of these fringes is inversely proportional to the spatial distance between the interfering WPs. In a similar fashion, we obtain interference fringes in real space when WPs traveling in opposite directions meet. The visibility of both real- and reciprocal-space interference fringes rapidly decreases with increasing temperature and vanishes. A theoretical description of the phase transition, considering the coexistence of condensed and noncondensed particles, for an out-of-equilibrium condensate such as ours is still missing, yet a comparison with theories developed for atomic condensates allows us to infer a critical temperature for the BEC-like transition when the visibility goes to zero.

Ferroelectricity by Bose-Einstein condensation in a quantum magnet.

Science.gov (United States)

Kimura, S; Kakihata, K; Sawada, Y; Watanabe, K; Matsumoto, M; Hagiwara, M; Tanaka, H

2016-09-26

The Bose-Einstein condensation is a fascinating phenomenon, which results from quantum statistics for identical particles with an integer spin. Surprising properties, such as superfluidity, vortex quantization or Josephson effect, appear owing to the macroscopic quantum coherence, which spontaneously develops in Bose-Einstein condensates. Realization of Bose-Einstein condensation is not restricted in fluids like liquid helium, a superconducting phase of paired electrons in a metal and laser-cooled dilute alkali atoms. Bosonic quasi-particles like exciton-polariton and magnon in solids-state systems can also undergo Bose-Einstein condensation in certain conditions. Here, we report that the quantum coherence in Bose-Einstein condensate of the magnon quasi particles yields spontaneous electric polarization in the quantum magnet TlCuCl 3 , leading to remarkable magnetoelectric effect. Very soft ferroelectricity is realized as a consequence of the O(2) symmetry breaking by magnon Bose-Einstein condensation. The finding of this ferroelectricity will open a new window to explore multi-functionality of quantum magnets.

EVALUATION OF SOLVENTS EFFICIENCY IN CONDENSATE BANKING REMOVAL

OpenAIRE

CORREA, TOMAS; TIAB, DJEBBAR; RESTREPO, DORA PATRICIA

2009-01-01

This work describes experimental design and tests performed to simulate gas condensate reservoir conditions below dew point in the laboratory using three different compositions of synthetic gas condensate. Methanol, propanol and methylene chloride are the solvents used to remove the condensate banking and improve the gas effective permeability near to the wellbore. Solvents are injected in Berea sandstone rock with similar petrophysical properties in order to compare the efficiency at removin...

Excitations of Bose-Einstein condensates at finite temperatures

International Nuclear Information System (INIS)

Rusch, M.

2000-01-01

Recent experimental observations of collective excitations of Bose condensed atomic vapours have stimulated interest in the microscopic description of the dynamics of a Bose-Einstein condensate confined in an external potential. We present a finite temperature field theory for collective excitations of trapped Bose-Einstein condensates and use a finite-temperature linear response formalism, which goes beyond the simple mean-field approximation of the Gross-Pitaevskii equation. The effect of the non-condensed thermal atoms we include using perturbation theory in a quasiparticle basis. This presents a simple scheme to understand the interaction between condensate and non-condensed atoms and enables us to include the effect the condensate has on collision dynamics. At first we limit our treatment to the case of a spatially homogeneous Bose gas. We include the effect of pair and triplet anomalous averages and thus obtain a gapless theory for the excitations of a weakly interacting system, which we can link to well known results for Landau and Beliaev damping rates. A gapless theory for trapped systems with a static thermal component follows straightforwardly. We then investigate finite temperature excitations of a condensate in a spherically symmetric harmonic trap. We avoid approximations to the density of states and thus emphasise finite size aspects of the problem. We show that excitations couple strongly to a restricted number of modes, giving rise to resonance structure in their frequency spectra. Where possible we derive energy shifts and lifetimes of excitations. For one particular mode, the breathing mode, the effects of the discreteness of the system are sufficiently pronounced that the simple picture of an energy shift and width fails. Experiments in spherical traps have recently become feasible and should be able to test our detailed quantitative predictions. (author)

Analysis study of the condensation heat transfer coefficient in the presence of noncondensable on PCCS vertical condenser tube using MARS-KS

Energy Technology Data Exchange (ETDEWEB)

Choi, Dong jae; Jang, Yeong jun; Lee, Yeon-Gun [Jeju National University, Jeju (Korea, Republic of); Kim, Sin [Chung-Ang University, Seoul (Korea, Republic of)

2015-10-15

The Passive Containment Cooling System (PCCS) to be introduced in advanced LWRs removes released energy to an external heat sink by a naturally driven flow. Containment through the condensation heat transfer phenomenon in the event of the loss of coolant accident (LOCA) or main steam line break (MSLB). As the released steam pressurizes the containment, the PCCS will activate to transport the decay heat In this study, a numerical analysis of the condensation heat transfer coefficients on the PCCS condenser tube is conducted using the MARS-KS code. The condensation heat transfer coefficients are obtained from JNU condensation tests performed on a 1000 long and 40 mm O.D. tube. The analysis condition covers 2 and 4 bar for the air mass fraction ranging from 0.1 to 0.8. The JNU single vertical condensation experimental results, Uchida's and Dehbi's correlation compared with the MARS-KS code's results at 2 and 4 bar. Experimental results and MARS-KS predicted heat transfer coefficient is different from the thermal resistances and Wall subcooling. An average relative error is 18.8% and 15% at 2 and 4 bar, respectively. Uchida's correlation is considered the noncondensable gas mass fraction only. Therefore, that is lower than MARS-KS results at 4 bar. Dehbi's correlation affected by ratio of the height-to-diameter, so its results are higher condensation heat transfer coefficient than MARS-KS predicted results.

Experimental study of EHD pseudo-dropwise condensation

International Nuclear Information System (INIS)

Yabe, A.; Taketani, T.; Yoshizawa, Y.; Sunada, K.

1991-01-01

This paper reports that in order to realize a higher performance heat pump, an electrohydrodynamical (EHD) condenser utilizing a combination of two kinds of EHD phenomena has been researched. In this study, to maximize the augmentation effect, an experimental study has been carried out to clarify the details of an EHD pseudo-dropwise condensation. The diameter of the drops has decreased with the increase of the electric field. The condensation heat transfer coefficients have increased in proportion to the electric field strength, realizing the maximum local heat transfer coefficients of over 9000 W/m 2 K for CFC113 and over 11000W/m 2 K for HCFC123. Furthermore, the heat transfer coefficients have become the same for the same electric field strength, independent of the surface temperature of the heat transfer plate, if the amount of the falling condensate is the same

Droplet condensation in rapidly decaying pressure fields

International Nuclear Information System (INIS)

Peterson, P.F.; Bai, R.Y.; Schrock, V.E.; Hijikata, K.

1992-01-01

Certain promising schemes for cooling inertial confinement fusion reactors call for highly transient condensation in a rapidly decaying pressure field. After an initial period of condensation on a subcooled droplet, undesirable evaporation begins to occur. Recirculation within the droplet strongly impacts the character of this condensation-evaporation cycle, particularly when the recirculation time constant is of the order of the pressure decay time constant. Recirculation can augment the heat transfer, delay the onset of evaporation, and increase the maximum superheat inside the drop by as much as an order of magnitude. This numerical investigation identifies the most important parameters and physics characterizing transient, high heat flux droplet condensation. The results can be applied to conceptual designs of inertial confinement fusion reactors, where initial temperature differences on the order of 1,500 K decay to zero over time spans the order of tens of milliseconds

Simulating the transient regime for main condensate system at Cernavoda NPP

International Nuclear Information System (INIS)

Nita, Iulian; Gheorghiu, Mihai; Prisecaru, Ilie; Dupleac, Daniel

2005-01-01

The purpose of this project is to make a Thermal Hydraulic Analysis of Main Condensate System for getting real-time answer of installation during regimes occurring during normal and abnormal operation. To obtain the analyses the MMS code was used. The boundaries of the systems analysis are extended to Main Feedwater System in order to get a realistic response of Deaerator equipment which are situated between those two systems and have entrances from both systems. In this way we made a complex analysis with main condenser and steam generators as boundaries. We obtained a model for the entire chain of condensate and feedwater preheater with interface just turbine bleed steam. From that we could reduce the number of assumptions necessary to make the analysis. The analyses consist in hydraulics and thermal hydraulics analyses, respectively. For the first case analysed are: - the nominal operation regime with main condensate pumps; - start-up regime with total circulate of condensate to condenser; - 25% MCR (Maximum Continuous Rate) regime (this regime was used in designing the condensate regulating valves at low flow; - 40% MCR regime (with circulate of some condensate flow to condenser); - operating regime of 60% MCR with one main condensate pump operating; - operating regime with auxiliary condensate pump; - operating regime with discharging a condensate flow to condensate storage tank. The thermal hydraulic analyses deal with normal and abnormal operating regimes, respectively. In the first case analysed are the following regimes: - nominal operating regime with main condensate pump operating 100% MCR; - transient regime, 100-80% MCR; - transient regime, 100-80-60% MCR with two pumps in operation and 60 % MCR with one main condensate pump in operation; - transient regime, 100-80-60-60-40 % MCR; - shut-down regime; - start-up regime from Hot zero power to rated power regime. Finally, for the abnormal operating regimes the analyses concerned: - transient regime 100

Hysteresis phenomenon during operation of gas condensate fields

Energy Technology Data Exchange (ETDEWEB)

Sadykh-Zade, E S; Karakashev, V K; Ismailov, D Kh

1966-01-01

Hysteresis behavior of gas-condensate mixtures was studied with a PVT apparatus. The study was conducted at 26 and 80/sup 0/C, with recombined samples having gas factors of 3,000, 6,500, and 10,000 cu meters per ton. Pressure on samples was decreased or increased at rates of 0.2; 0.1; 0.05; and 0.025 atm per sec. Composition of gas- condensate is given. It is reported that different amounts of liquid were produced by condensation and evaporation processes, i.e., results depended on whether pressure was being increased or decreased. It is suggested that the effect of hysteresis should be considered in operation of gas-condensate fields.

Implementation and validation of a condensation model in ANSYS

International Nuclear Information System (INIS)

Lehmkuhl, J.; Kelm, S.; Allelein, H.J.; Forschungszentrum Juelich

2012-01-01

During design-based beyond-design accidents large amounts of steam and hydrogen are released onto the containment. The knowledge on the local distribution of gases and atmospheric conditions is therefore necessary for the design of safety systems or emergency measures. Condensation processes have a significant influence on the thermal hydraulics, the hydrogen combustion and the aerosol behavior in the containment. The presented one-phase condensation model was developed for an effective CFD modeling of condensation processes in ANSYS CFX for accident analyses. Based on the assumption that wall condensation is mainly determined by the mass transport the assumption of thermal equilibrium can be used for one-phase calculations. The modeling concept is applicable for wall and volume condensation and has been implemented.

Optimal design of condenser volume in nuclear power plant

International Nuclear Information System (INIS)

Zheng Jing; Yan Changqi; Wang Jianjun

2011-01-01

The condenser is an important component in the nuclear power plant,whose dimension will influence the economy and the arrangement of the nuclear power plant.In this paper, the calculation model was established according to the design experience. The corresponding codes were also developed. The sensitivity of design parameters which influence the condenser Janume was analyzed. The present optimal design of the condenser, aiming at the volume minimization, was carried out with the self-developed complex-genetic algorithm. The results show that the reference condenser design is far from the best scheme. In addition, the results also verify the feasibility of the complex-genetic algorithm. Furthermore, the results of this paper can provide reference for the design of the condenser. (authors)

Method and apparatus for high-efficiency direct contact condensation

Science.gov (United States)

Bharathan, Desikan; Parent, Yves; Hassani, A. Vahab

1999-01-01

A direct contact condenser having a downward vapor flow chamber and an upward vapor flow chamber, wherein each of the vapor flow chambers includes a plurality of cooling liquid supplying pipes and a vapor-liquid contact medium disposed thereunder to facilitate contact and direct heat exchange between the vapor and cooling liquid. The contact medium includes a plurality of sheets arranged to form vertical interleaved channels or passageways for the vapor and cooling liquid streams. The upward vapor flow chamber also includes a second set of cooling liquid supplying pipes disposed beneath the vapor-liquid contact medium which operate intermittently in response to a pressure differential within the upward vapor flow chamber. The condenser further includes separate wells for collecting condensate and cooling liquid from each of the vapor flow chambers. In alternate embodiments, the condenser includes a cross-current flow chamber and an upward flow chamber, a plurality of upward flow chambers, or a single upward flow chamber. The method of use of the direct contact condenser of this invention includes passing a vapor stream sequentially through the downward and upward vapor flow chambers, where the vapor is condensed as a result of heat exchange with the cooling liquid in the contact medium. The concentration of noncondensable gases in the resulting condensate-liquid mixtures can be minimized by controlling the partial pressure of the vapor, which depends in part upon the geometry of the vapor-liquid contact medium. In another aspect of this invention, the physical and chemical performance of a direct contact condenser can be predicted based on the vapor and coolant compositions, the condensation conditions. and the geometric properties of the contact medium.

Steam condensation on finned tubes, in the presence of non-condensable gases and aerosols: Influence of impaction, diffusiophoresis and settling on aerosol deposition

International Nuclear Information System (INIS)

Munoz-Cobo, J.L.; Pena, J.; Herranz, L.E.; Perez-Navarro, A.

2005-01-01

This paper presents a mechanistic model to predict the steam condensation on containment finned tube heat exchangers in the presence of non-condensable gases (NC) and aerosols. The total thermal resistance from the bulk gas to the coolant is formulated as a parallel combination of the convective and condensation gas resistances coupled in series to those of condensate layer, the aerosol fouling layer, the wall, and the coolant. The condensate layer thermal resistance is calculated by means of an Adamek-based condensation model. The aerosol fouling layer is computed based on diffusiophoresis, settling and impaction mechanisms. The gas mixture (steam plus NC) thermal resistance is formulated based on a diffusion layer modeling. Finally, this paper presents a Montecarlo method implemented in the FORTRAN code TAEROSOL that is able to compute the amount of aerosol mass that is deposited by impaction on the top of the finned tubes. The model results are compared with the available experimental data of the CONGA European project

Preoperational test report, primary ventilation condensate system

Energy Technology Data Exchange (ETDEWEB)

Clifton, F.T.

1997-01-29

Preoperational test report for Primary Ventilation Condensate System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides a collection point for condensate generated by the W-030 primary vent offgas cooling system serving tanks AYIOI, AY102, AZIOI, AZI02. The system is located inside a shielded ventilation equipment cell and consists of a condensate seal pot, sampling features, a drain line to existing Catch Tank 241-AZ-151, and a cell sump jet pump. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

Bose condensates make quantum leaps and bounds

International Nuclear Information System (INIS)

Castin, Y.; Dum, R.; Sinatra, A.

1999-01-01

Since the first observation in 1995 of Bose-Einstein condensation in dilute atomic gases, atomic physicists have made extraordinary progress in understanding this unusual quantum state of matter. BOSE-EINSTEIN condensation is a macroscopic quantum phenomenon that was first predicted by Albert Einstein in the 1920s, at a time when quantum theory was still developing and was being applied to microscopic systems, such as individual particles and atoms. Einstein applied the new concept of Bose statistics to an ideal gas of identical atoms that were at thermal equilibrium and trapped in a box. He predicted that at sufficiently low temperatures the particles would accumulate in the lowest quantum state in the box, giving rise to a new state of matter with many unusual properties. The crucial point of Einstein's model is the absence of interactions between the particles in the box. However, this makes his prediction difficult to test in practice. In most real systems the complicating effect of particle interactions causes the gas to solidify well before the temperature for Bose-Einstein condensation is reached. But techniques developed in the past four years have allowed physicists to form Bose-Einstein condensates for a wide range of elements. In this article the authors describe the latest advances in Bose-Einstein condensation. (UK)

Bose-Einstein condensates in atomic gases: simple theoretical results

International Nuclear Information System (INIS)

Castin, Y.

2001-01-01

The author presents the theory of the Bose-Einstein condensation along with a discussion of experimental tests. The author deals successively with the following topics: - the ideal Bose gas in a trap (first in a harmonic trap and then in a more general trap), - a model for the atomic interaction, - interacting Bose gas in the Hartree-Fock approximation, - properties of the condensate wavefunction, - the Gross-Pitaevskii equation, - Bogoliubov approach and thermodynamical stability, - phase coherence properties at the Bose-Einstein condensate, and - symmetry-breaking description of condensates. (A.C.)

BWR condensate filtration studies

International Nuclear Information System (INIS)

Wilson, J.A.; Pasricha, A.; Rekart, T.E.

1993-09-01

Poor removal of particulate corrosion products (especially iron) from condensate is one of the major problems in BWR systems. The presence of activated corrosion products creates ''hot spots'' and increases piping dose rates. Also, fuel efficiency is reduced and the risk of fuel failure is increased by the deposit of corrosion products on the fuel. Because of these concerns, current EPRI guidelines call for a maximum of 2 ppb of iron in the reactor feedwater with a level of 0.5 ppb being especially desirable. It has become clear that conventional deep bed resins are incapable of meeting these levels. While installation of prefilter systems is an option, it would be more economical for plants with naked deep beds to find an improved bead resin for use in existing systems. BWR condensate filtration technologies are being tested on a condensate side stream at Hope Creek Nuclear Generating Station. After two years of testing, hollow fiber filters (HFF) and fiber matrix filters (FMF), and low crosslink cation resin, all provide acceptable results. The results are presented for pressure drop, filtration efficiency, and water quality measurements. The costs are compared for backwashable non-precoat HFF and FMF. Results are also presented for full deep bed vessel tests of the low crosslink cation resin

Bosonization with inclusion of the gluon condensate

International Nuclear Information System (INIS)

Ebert, D.; Volkov, M.K.

1994-01-01

The effects of the gluon condensate on the quark condensate and on masses and coupling constants of composite mesons are discussed within a QCD-motivated Nambu-Jona-Lasinio model for zero temperature as well as for the case of finite temperature and baryon number density. (orig.)

Bose–Einstein condensation in the Rindler space

Directory of Open Access Journals (Sweden)

Shingo Takeuchi

2015-11-01

Full Text Available Based on the Unruh effect, we calculate the critical acceleration of the Bose–Einstein condensation in a free complex scalar field at finite density in the Rindler space. Our model corresponds to an ideal gas performing constantly accelerating motion in a Minkowski space–time at zero-temperature, where the gas is composed of the complex scalar particles and it can be thought to be in a thermal-bath with the Unruh temperature. In the accelerating frame, the model will be in the Bose–Einstein condensation state at low acceleration; on the other hand, there will be no condensation at high acceleration by the thermal excitation brought into by the Unruh effect. Our critical acceleration is the one at which the Bose–Einstein condensation begins to appear in the accelerating frame when we decrease the acceleration gradually. To carry out the calculation, we assume that the critical acceleration is much larger than the mass of the particle.

Bose-condensation through resonance decay

International Nuclear Information System (INIS)

Ornik, U.; Pluemer, M.; Strottman, D.

1993-04-01

We show that a system described by an equation of state which contains a high number of degrees of freedom (resonances) can create a considerable amount of superfluid (condensed) pions through the decay of short-lived resonances, if baryon number and entropy are large and the dense matter decouples from chemical equilibrium earlier than from thermal equilibrium. The system cools down faster in the presence of a condensate, an effect that may partially compensate the enhancement of the lifetime expected in the case of quark-gluon-plasma formation. (orig.). 3 figs

Dentine bond strength of a composite resin polymerized with conventional light and argon laser Resistência de união à dentina de resina composta polimerizada com luz halógena e laser de argônio

Directory of Open Access Journals (Sweden)

Patricia Ramos Lloret

2004-09-01

Full Text Available The use of argon laser (488 nm has been suggested as a new alternative for polymerizing adhesive materials. This study aimed to evaluate the tensile bond strength of a microfilled composite (A110, 3M inserted by incremental technique (3 increments of 1 mm and by single increment (3 mm polymerized by argon laser for 10, 20 and 30 seconds and halogen light for 40 seconds. Eighty (8 groups of 10 teeth freshly extracted bovine teeth were stored in a freezer in distilled water for one week. The crowns were cross-sectioned from the roots. Pulpectomy was performed and the pulp chambers were sealed with wax. The buccal surfaces of the teeth were ground with wet sandpaper (grains: 120, 400, and 600 to expose the surface dentin, and the teeth were then included in acrylic resin. A metal device was used to fix each sample and a black propylene matrix25 (3 mm high with an internal millimetric delimitation was used to insert the material according to the groups studied. The polymerization intervals were of 10, 20 and 30 seconds for the laser polymerization and 40 seconds for the conventional polymerization. Tensile tests were performed by a Universal Testing Machine 4442 (Instron at a speed of 0.5 mm/min and 500 N load. According to the methodology used, the incremental technique increased bond strength values. There was no difference between the studied polymerization techniques when resin was filled in 3 increments.O uso do laser de argônio (488 nm tem sido sugerido como uma nova alternativa para polimerização de materiais adesivos. Este estudo tem o objetivo de avaliar a resistência adesiva de uma resina composta microparticulada (A110, 3M inserida pela técnica incremental (3 incrementos de 1 mm e de incremento único (3 mm polimerizada com laser de argônio por 10, 20 e 30 segundos e com luz halógena por 40 segundos. Oitenta (8 grupos com 10 dentes dentes bovinos recém-extraídos foram armazenados em geladeira, em água destilada, por uma semana

Disposal of aqueous condensate from high efficiency gas boilers

Energy Technology Data Exchange (ETDEWEB)

Hardwick, G J; Pattison, J R

1984-01-01

If highly efficient gas-fired condensing heating appliances are installed in Britain, the aqueous condensate produced can be conveniently run into existing sewage drains. The part of the drainage system that is most vulnerable to corrosion from the mildly acid condensate is that portion adjacent to the domestic premises. The tests described indicate that this is not at risk and the only precaution that might be considered necessary is to avoid running the condensate over galvanized drain covers in order to prevent unsightly staining. Water authorities in Britain and detailed studies in the US and Holland confirm that the condensate - after dilution by domestic waste, sewage, and rainwater - would be harmless to municipal sewage systems and would not, either in volume or chemical composition, affect the working of existing sewage treatment plants.

Accretion of a ghost condensate by black holes

International Nuclear Information System (INIS)

Frolov, Andrei V.

2004-01-01

The intent of this paper is to point out that the accretion of a ghost condensate by black holes could be extremely efficient. We analyze steady-state spherically symmetric flows of the ghost fluid in the gravitational field of a Schwarzschild black hole and calculate the accretion rate. Unlike minimally coupled scalar field or quintessence, the accretion rate is set not by the cosmological energy density of the field, but by the energy scale of the ghost condensate theory. If hydrodynamical flow is established, it could be as high as a tenth of a solar mass per second for 10 MeV scale ghost condensate accreting onto a stellar-sized black hole, which puts serious constraints on the parameters of the ghost condensate model

Interference of an array of independent Bose-Einstein condensates

International Nuclear Information System (INIS)

Hadzibabic, Zoran; Stock, Sabine; Battelier, Baptiste; Bretin, Vincent; Dalibard, Jean

2004-01-01

We have observed high-contrast matter wave interference between 30 Bose-Einstein condensates with uncorrelated phases. Interferences were observed after the independent condensates were released from a one-dimensional optical lattice and allowed to overlap. This phenomenon is explained with a simple theoretical model, which generalizes the analysis of the interference of two condensates

Uso de resíduo industrial a base de resina fenólica como carga para o polipropileno Use of industrial waste based on phenolic resin as filler for polypropylene

Directory of Open Access Journals (Sweden)

André P. Cavalcante

2012-01-01

Full Text Available O objetivo deste estudo foi analisar a viabilidade técnica do uso de resíduo industrial composto de resina fenólica, lignocelulose, carbonato de cálcio, talco, mica e negro de fumo como carga para o polipropileno (PP. Compósitos de PP com 10, 15 e 20% em massa do resíduo foram processados em extrusora de rosca dupla e moldados por injeção. Os compósitos moldados foram caracterizados por microscopia eletrônica de varredura (MEV, análises térmicas (DSC e TGA, ensaios mecânicos (tração, flexão e impacto e ensaio termo-mecânico (HDT. Os compósitos moldados apresentaram partículas do resíduo com tamanhos inferiores a 500 µm dispersas na matriz de polipropileno. As partículas do resíduo atuaram como agentes de nucleação da cristalização do PP. Os compósitos apresentaram maior resistência à degradação térmica, balanço de rigidez e resistência com aumento do módulo sob flexão e diminuição da resistência à tração, manutenção da resistência ao impacto sob entalhe, e aumento da temperatura de distorção ao calor (HDT. O desempenho dos compósitos demonstrou que o resíduo industrial de resina fenólica pode ser empregado como carga funcional para o PP. Além disso, os compósitos desenvolvidos representam uma alternativa para a reciclagem do resíduo industrial de resina fenólica.The aim of this study was to assess the technical feasibility of using industrial waste composed of phenolic resin, lignocellulose, calcium carbonate, talc, mica and carbon black as filler for polypropylene (PP. Composites of PP with 10, 15 and 20 wt% of the waste were processed in a twin-screw extruder followed by injection molding. Molded composites were characterized by scanning electron microscopy (SEM, thermal analyses (DSC and TGA, mechanical tests (tensile, flexural and impact and thermo-mechanical test (HDT. The composites showed residue particles with sizes less than 500 µm dispersed in the PP matrix. The residue particles

Contact condensation effects in the main coolant pipe

International Nuclear Information System (INIS)

Haefner, W.; Fischer, K.

1990-01-01

Contact condensation effects may occur in a pressurized water reactor (PWR) after a loss of coolant accident (LOCA) when emergency core cooling (ECC) water is injected contact with escaping steam which is generated within the core. The condensation which takes place may cause a sudden depressurization leading to the formation of water slugs. The interaction between the transient condensation and the inertia of the flow may also result in large amplitude flow and pressure oscillations. These contact condensation effects are of great importance for the mass flow distribution and the coolant water supply to the reactor core. To examine those complex processes, large computer codes are necessary. The development and verification of analytical models requires greatly simplified flow boundary conditions from experiments and a sufficiently large base of experimental data. Separate models have been developed for interfacial exchange of mass, momentum and energy with respect to the associated flow regime. Therefore, an adequate description of the condensation process requires the modeling of two different topics: the prediction of the flow regime and the calculation of the interfacial exchange. (author)

Analysis of water microdroplet condensation on silicon surfaces

Science.gov (United States)

Honda, Takuya; Fujimoto, Kenya; Yoshimoto, Yuta; Mogi, Katsuo; Kinefuchi, Ikuya; Sugii, Yasuhiko; Takagi, Shu; Univ. of Tokyo Team; Tokyo Inst. of Tech. Team

2016-11-01

We observed the condensation process of water microdroplets on flat silicon (100) surfaces by means of the sequential visualization of the droplets using an environmental scanning electron microscope. As previously reported for nanostructured surfaces, the condensation process of water microdroplets on the flat silicon surfaces also exhibits two modes: the constant base (CB) area mode and the constant contact angle (CCA) mode. In the CB mode, the contact angle increases with time while the base diameter is constant. Subsequently, in the CCA mode, the base diameter increases with time while the contact angle remains constant. The dropwise condensation model regulated by subcooling temperature does not reproduce the experimental results. Because the subcooling temperature is not constant in the case of a slow condensation rate, this model is not applicable to the condensation of the long time scale ( several tens of minutes). The contact angle of water microdroplets ( several μm) tended to be smaller than the macro contact angle. Two hypotheses are proposed as the cause of small contact angles: electrowetting and the coalescence of sub- μm water droplets.

Physics through the 1990s: Condensed-matter physics

International Nuclear Information System (INIS)

1986-01-01

In this survey of condensed-matter physics we describe the current status of the field, present some of the significant discoveries and developments in it since the early 1970s, and indicate some areas in which we expect that important discoveries will be made in the next decade. We also describe the resources that will be required to produce these discoveries. This volume is organized as follows. The first part is devoted to a discussion of the importance of condensed-matter physics; to brief descriptions of several of the most significant discoveries and advances in condensed-matter physics made in the 1970s and early 1980s, and of areas that appear to provide particularly exciting research opportunities in the next decade; and to a presentation of the support needs of condensed-matter physicists in the next decade and of recommendations aimed at their provision. Next, the subfields of condensed-matter physics are reviewed in detail. The volume concludes with several appendixes in which new materials, new experimental techniques, and the National Facilities are reviewed

Pion condensation in symmetric nuclear matter

Science.gov (United States)

Kabir, K.; Saha, S.; Nath, L. M.

1988-01-01

Using a model which is based essentially on the chiral SU(2)×SU(2) symmetry of the pion-nucleon interaction, we examine the possibility of pion condensation in symmetric nucleon matter. We find that the pion condensation is not likely to occur in symmetric nuclear matter for any finite value of the nuclear density. Consequently, no critical opalescence phenomenom is expected to be seen in the pion-nucleus interaction.

Refrigeration. Heat Transfer. Part I: Evaporators and Condensers

DEFF Research Database (Denmark)

Knudsen, Hans-Jørgen Høgaard

2002-01-01

The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation.......The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation....

MARS-KS Code Assessment for Condensation Heat Transfer in Horizontal Tube with the Presence of Non-Condensable Gas using Purdue Experiment

International Nuclear Information System (INIS)

Jeon, Seong Su; Lee, Byung Chul; Park, Ju Yeop; Seul, Kwang Won

2011-01-01

In South Korea, advanced power reactor plus (APR+), as a Korean specific reactor, is currently under development for the export strategy. In order to raise competitiveness of the APR+ in the world market, it is necessary to develop the original technology for the improved technology, economics, and safety features. For this purpose, a passive auxiliary feedwater system (PAFS) was adopted as an improved safety design concept of APR+: and then there have been many efforts to develop the PAFS. According to PAFS design concept, PAFS can completely replace the auxiliary feedwater system. When the design basis accident, in which feedwater is unavailable, occurs, the PAFS can remove the residual heat in the core and then prevent the core damage. In the PAFS with the horizontal type heat exchanger, two-phase natural circulation, condensation heat transfer in tube, boiling heat transfer in pool, natural convection in pool, etc. are considered as very important thermalhydraulic phenomena (see Fig. 1). Compared with the vertical heat exchanger from these phenomena, the major difference of the horizontal heat exchanger is the condensation heat transfer phenomena in the tube side. There have been many efforts to understand the condensation heat transfer with in the presence of NC gas in tube but most researches focused on the condensation heat transfer in vertical tube. Therefore the details of the condensation heat transfer in the presence of NC gas in horizontal condenser tubes are not well understood. In order to develop the safety evaluation system for APR+ PAFS, it is required to evaluate the capability and applicability of the MARS-KS code for modeling the condensation heat transfer in the horizontal tube with NC gas because many heat transfer correlations in MARS-KS are known to have much uncertainty. In particular, there is no reliable model for the condensation phenomena in horizontal tube with NC gas. In order to assess the MARS-KS code results and identify the

Condensed matter analogues of cosmology

Science.gov (United States)

Kibble, Tom; Srivastava, Ajit

2013-10-01

It is always exciting when developments in one branch of physics turn out to have relevance in a quite different branch. It would be hard to find two branches farther apart in terms of energy scales than early-universe cosmology and low-temperature condensed matter physics. Nevertheless ideas about the formation of topological defects during rapid phase transitions that originated in the context of the very early universe have proved remarkably fruitful when applied to a variety of condensed matter systems. The mathematical frameworks for describing these systems can be very similar. This interconnection has led to a deeper understanding of the phenomena in condensed matter systems utilizing ideas from cosmology. At the same time, one can view these condensed matter analogues as providing, at least in a limited sense, experimental access to the phenomena of the early universe for which no direct probe is possible. As this special issue well illustrates, this remains a dynamic and exciting field. The basic idea is that when a system goes through a rapid symmetry-breaking phase transition from a symmetric phase into one with spontaneously broken symmetry, the order parameter may make different choices in different regions, creating domains that when they meet can trap defects. The scale of those domains, and hence the density of defects, is constrained by the rate at which the system goes through the transition and the speed with which order parameter information propagates. This is what has come to be known as the Kibble-Zurek mechanism. The resultant scaling laws have now been tested in a considerable variety of different systems. The earliest experiments illustrating the analogy between cosmology and condensed matter were in liquid crystals, in particular on the isotropic-to-nematic transition, primarily because it is very easy to induce the phase transition (typically at room temperature) and to image precisely what is going on. This field remains one of the

Dry coolers and air-condensing units (Review)

Science.gov (United States)

Milman, O. O.; Anan'ev, P. A.

2016-03-01

The analysis of factors affecting the growth of shortage of freshwater is performed. The state and dynamics of the global market of dry coolers used at electric power plants are investigated. Substantial increase in number and maximum capacity of air-cooled condensers, which have been put into operation in the world in recent years, are noted. The key reasons facilitating the choice of developers of the dry coolers, in particular the independence of the location of thermal power plant from water sources, are enumerated. The main steam turbine heat removal schemes using air cooling are considered, their comparison of thermal efficiency is assessed, and the change of three important parameters, such as surface area of heat transfer, condensate pump flow, and pressure losses in the steam exhaust system, are estimated. It is shown that the most effective is the scheme of direct steam condensation in the heat-exchange tubes, but other schemes also have certain advantages. The air-cooling efficiency may be enhanced much more by using an air-cooling hybrid system: a combination of dry and wet cooling. The basic applied constructive solutions are shown: the arrangement of heat-exchange modules and the types of fans. The optimal mounting design of a fully shopassembled cooling system for heat-exchange modules is represented. Different types of heat-exchange tubes ribbing that take into account the operational features of cooling systems are shown. Heat transfer coefficients of the plants from different manufacturers are compared, and the main reasons for its decline are named. When using evaporative air cooling, it is possible to improve the efficiency of air-cooling units. The factors affecting the faultless performance of dry coolers (DC) and air-condensing units (ACU) and the ways of their elimination are described. A high velocity wind forcing reduces the efficiency of cooling systems and creates preconditions for the development of wind-driven devices. It is noted that

Specific interactions versus counterion condensation. 2. Theoretical treatment within the counterion condensation theory.

Science.gov (United States)

Donati, Ivan; Benegas, Julio C; Cesàro, Attilio; Paoletti, Sergio

2006-05-01

Polyuronates such as pectate and alginate are very well-known examples of biological polyelectrolytes undergoing, upon addition of divalent cations, an interchain association that acts as the junction of an eventually formed stable hydrogel. In the present paper, a thermodynamic model based on the counterion condensation theory has been developed to account for this cation-induced chain pairing of negatively charged polyelectrolytes. The strong interactions between cross-linking ions and uronate moieties in the specific binding site have been described in terms of chemical bonding, with complete charge annihilation between the two species. The chain-pairing process is depicted as progressively increasing with the concentration of cross-linking counterions and is thermodynamically defined by the fraction of each species. On these bases, the total Gibbs energy of the system has been expressed as the sum of the contributions of the Gibbs energy of the (single) chain stretches and of the (associated) dimers, weighted by their respective fractions 1 - theta and theta. In addition, the model assumes that the condensed divalent counterions exhibit an affinity free-energy for the chain, G(C)(aff,0), and the junction, G(D)(aff,0), respectively. Moreover, a specific Gibbs energy of chemical bonding, G(bond,0), has been introduced as the driving force for the formation of dimers. The model provides the mathematical formalism for calculating the fraction, theta, of chain dimers formed and the amount of ions condensed and bound onto the polyelectrolyte when two different types of counterions (of equal or different valence) are present. The effect of the parameter G(bond,0) has been investigated and, in particular, its difference from G(C,D)(aff,0) was found to be crucial in determining the distribution of the ions into territorial condensation and chemical bonding, respectively. Finally, the effect of the variation of the molar ratio between cross-linking ions and uronic groups

Spectroscopy of dark soliton states in Bose-Einstein condensates

International Nuclear Information System (INIS)

Bongs, K; Burger, S; Hellweg, D; Kottke, M; Dettmer, S; Rinkleff, T; Cacciapuoti, L; Arlt, J; Sengstock, K; Ertmer, W

2003-01-01

Experimental and numerical studies of the velocity field of dark solitons in Bose-Einstein condensates are presented. The formation process after phase imprinting as well as the propagation of the emerging soliton are investigated using spatially resolved Bragg spectroscopy of soliton states in Bose-Einstein condensates of 87 Rb. A comparison of experimental data to results from numerical simulations of the Gross-Pitaevskii equation clearly identifies the flux underlying a dark soliton propagating in a Bose-Einstein condensate. The results allow further optimization of the phase imprinting method for creating collective excitations of Bose-Einstein condensates

49 CFR 1243.2 - Condensed balance sheet.

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Condensed balance sheet. 1243.2 Section 1243.2... § 1243.2 Condensed balance sheet. Commencing with reports for the 3 months beginning January 1, 1972, and... hereby, required to compile and file quarterly reports of balance sheet items in accordance with...

Finite temperature effects in Bose-Einstein condensed dark matter halos

International Nuclear Information System (INIS)

Harko, Tiberiu; Madarassy, Enikö J.M.

2012-01-01

Once the critical temperature of a cosmological boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. Zero temperature condensed dark matter can be described as a non-relativistic, Newtonian gravitational condensate, whose density and pressure are related by a barotropic equation of state, with barotropic index equal to one. In the present paper we analyze the effects of the finite dark matter temperature on the properties of the dark matter halos. We formulate the basic equations describing the finite temperature condensate, representing a generalized Gross-Pitaevskii equation that takes into account the presence of the thermal cloud. The static condensate and thermal cloud in thermodynamic equilibrium is analyzed in detail, by using the Hartree-Fock-Bogoliubov and Thomas-Fermi approximations. The condensed dark matter and thermal cloud density and mass profiles at finite temperatures are explicitly obtained. Our results show that when the temperature of the condensate and of the thermal cloud are much smaller than the critical Bose-Einstein transition temperature, the zero temperature density and mass profiles give an excellent description of the dark matter halos. However, finite temperature effects may play an important role in the early stages of the cosmological evolution of the dark matter condensates

Accelerators for condensed matter research

International Nuclear Information System (INIS)

Williams, P.R.

1990-01-01

The requirement for high energy, high luminosity beams has stimulated the science and engineering of accelerators to a point where they open up opportunities for new areas of scientific application to benefit from the advances driven by particle physics. One area of great importance is the use of electron or positron storage rings as a source of intense VUV or X-ray synchrotron radiation. An accelerator application that has grown in prominence over the last 10 years has been spallation neutron sources. Neutrons offer an advantage over X-rays as a condensed matter probe because the neutron energy is usually of the same order as the room temperature thermal energy fluctuations in the sample being studied. Another area in which accelerators are playing an increasingly important role in condensed matter research concerns the use of Mu mesons, Muons, as a probe. This paper also presents a description of the ISIS Spallation Neutron Source. The design and status of the facility are described, and examples are given of its application to the study of condensed matter. (N.K.)

Condensation During Nuclear Reactor Loca

International Nuclear Information System (INIS)

Rihan, Y.; Teamah, M.; Sorour, M.; Soliman, S.

2008-01-01

Two-phase channel flow with condensation is a common phenomenon occurs in a number of nuclear reactor accident scenarios. It also plays an important role during the operation of the safety coolant injection systems in advanced nuclear reactors. Semiempirical correlations and simple models based on the analogy between heat and mass transfer processes have been previously applied. Rigorous models, compatible with the state-of-the-art numerical algorithms used in thermal-hydraulic computer codes, are scare, and are of great interest. The objective of this research is to develop a method for modeling condensation, with noncondensable gases, compatible with the state-of-the-art numerical methods for the solution of multi-phase field equations. A methodology for modeling condensation, based on the stagnant film theory, and compatible with the reviewed numerical algorithms, is developed. The model treats the coupling between the heat and mass transfer processes, and allows for an implicit treatment of the mass and momentum exchange terms as the gas-liquid interphase, without iterations. The developed model was used in the application of loss of coolant in pressurized water reactor accidents

Scandinavian experience of titanium condensers

International Nuclear Information System (INIS)

Multer, I.; Hedstroem, M.

1985-01-01

The Albrass condenser tubing in Sweden and Finnish nuclear power plants has caused much concern. After the appearance of the first tube leak, the deterioration has been very rapid. A typical development is represented by the Ringhals unit 2 eddy current (EC) measurements. They are, despite the difference in salinity, almost identical with Forsmark units 1 and 2 and units 1 and 2 of the TVO power company at Olkiluoto, Finland. For instance, in summer 1984, 3000 tubes were plugged in TVO 2 after four years of operation. The cause was pitting and/or erosion-corrosion. The failure rate, although the plugging criteria have been different from the EPRI concept, has exceeded that reported in the US and UK; and it has been necessary, especially with the strict feed water chemistry requirements in the PWR's, to arrange for retubing after a very short time, approximately 3 years after the first leak. The history of the nuclear plant condensers is shown; the average condenser life span has been approximately 6.5 years

Limitations of the condensed history method for low-energy electrons

International Nuclear Information System (INIS)

Martin, W.R.; Ballinger, C.T.; Rathkopf, J.A.

1991-01-01

A systematic evaluation of the conventional, condensed history electron transport methodology has been performed through comparisons with more accurate single-scatter Monte Carlo calculations. These comparisons highlight the inaccuracies associated with the condensed history method and indicate its range of validity. The condensed history method is used in codes such as MCNP4, SANDYL, ETRAN, ITS, and EGS and requires a number of restrictive assumptions about the scattering characteristics to make tractable the analytical solution to the infinite-medium transport equation. Distributions describing electron characteristics after multiple collisions (multiscatter distributions) are constructed from such solutions and serve as the heart of the condensed history codes. A two-level approach is taken to quantify the errors inherent in condensed history. First, conventional condensed history multiscattering distributions in energy and angle are compared directly with analogous distributions generated with a single-scatter Monte Carlo code. This recently developed code directly simulates individual electron interactions. Second, the conventional distributions are replaced in the condensed history code by distributions constructed via a single-scatter Monte Carlo simulation

Assessment of Condenser Design in the Cooling System of PWR

International Nuclear Information System (INIS)

Sukmanto Dibyo

2008-01-01

This paper explains various cases related to the problem of condenser design principle. Condenser equipment is circuit component of cooling that is very important. Steam that goes down from the turbine, flowing to the condenser and the steam is condensate to be water. Step of design is beginning from identification of problem until mechanic design. Usually, the condenser is designed by conservative certain levels, as well as thermal aspect or mechanic. Beside that, the design analysis is also anticipated to the existing of degradation due to aging therefore safety aspect and requirement are accepted. The assessment that related to the condenser design has been discussed. Most important aspect is obtaining of performances. Beside that, the discussion is also described about design method and that complication should consider aspect of thermal design, physics, economic, aspect of corrosion and others factors. (author)

Heat transfer from a high temperature condensable mixture

International Nuclear Information System (INIS)

Chan, S.H.; Cho, D.H.; Condiff, D.W.

1978-01-01

A new development in heat transfer is reported. It is concerned with heat transfer from a gaseous mixture that contains a condensable vapor and is at very high temperature. In the past, heat transfer associated with either a condensable mixture at low temperature or a noncondensable mixture at high temperature has been investigated. The former reduces to the classical problem of fog formation in, say, atmosphere where the rate of condensation is diffusion controlled (molecular or conductive diffusions). In the presence of noncondensable gases, heat transfer to a cooler boundary by this mechanism is known to be drastically reduced. In the latter case, where the high temperature mixture is noncondensable, radiative transfer may become dominant and a vast amount of existing literature exists on this class of problem. A fundamentally different type of problem of relevance to recent advances in open cycle MHD power plants and breeder reactor safety is considered. In the advanced coal-fired power plant using MHD as a topping cycle, a condensable mixture is encountered at temperatures of 2000 to 3000 0 . Condensation of the vaporized slag and seed materials at such a high temperature can take place in the MHD generator channel as well as in the radiant boiler. Similarly, in breeder reactor accident analyses involving hypothetical core disruptive accidents, a UO 2 vapor mixture at 400 0 K or higher is often considered. Since the saturation temperature of UO 2 at one atmosphere is close to 4000 0 K, condensation is also likely at a very high temperature. Accordingly, an objective of the present work is to provide an understanding of heat transfer and condensation mechanics insystems containing a high temperature condensable mixture. The results of the study show that, when a high temperature mixture is in contact with a cooler surface, a thermal boundary layer develops rapidly because of intensive radiative cooling from the mixture

Condensate fluctuations of interacting Bose gases within a microcanonical ensemble.

Science.gov (United States)

Wang, Jianhui; He, Jizhou; Ma, Yongli

2011-05-01

Based on counting statistics and Bogoliubov theory, we present a recurrence relation for the microcanonical partition function for a weakly interacting Bose gas with a finite number of particles in a cubic box. According to this microcanonical partition function, we calculate numerically the distribution function, condensate fraction, and condensate fluctuations for a finite and isolated Bose-Einstein condensate. For ideal and weakly interacting Bose gases, we compare the condensate fluctuations with those in the canonical ensemble. The present approach yields an accurate account of the condensate fluctuations for temperatures close to the critical region. We emphasize that the interactions between excited atoms turn out to be important for moderate temperatures.

Increasing the efficiency of the condensing boiler

Science.gov (United States)

Zaytsev, ON; Lapina, EA

2017-11-01

Analysis of existing designs of boilers with low power consumption showed that the low efficiency of the latter is due to the fact that they work in most cases when the heating period in the power range is significantly less than the nominal power. At the same time, condensing boilers do not work in the most optimal mode (in condensing mode) in the central part of Russia, a significant part of their total operating time during the heating season. This is due to existing methods of equipment selection and joint operation with heating systems with quantitative control of the coolant. It was also revealed that for the efficient operation of the heating system, it is necessary to reduce the inertia of the heat generating equipment. Theoretical patterns of thermal processes in the furnace during combustion gas at different radiating surfaces location schemes considering the influence of the very furnace configuration, characterized in that to reduce the work condensing boiler in conventional gas boiler operation is necessary to maintain a higher temperature in the furnace (in the part where spiral heat exchangers are disposed), which is possible when redistributing heat flow - increase the proportion of radiant heat from the secondary burner emitter allow Perey For the operation of the condensing boiler in the design (condensation) mode practically the entire heating period.

Condensation in a two-phase pool

International Nuclear Information System (INIS)

Duffey, R.B.; Hughes, E.D.

1991-01-01

We consider the case of vapor condensation in a liquid pool, when the heat transfer is controlled by heat losses through the walls. The analysis is based on drift flux theory for phase separation in the pool, and determines the two-phase mixture height for the pool. To our knowledge this is the first analytical treatment of this classic problem that gives an explicit result, previous work having established the result for the evaporative case. From conservation of mass and energy in a one-dimensional steady flow, together with a void relation between the liquid and vapor fluxes, we determine the increase in the mixture level from the base level of the pool. It can be seen that the thermal and hydrodynamic influences are separable. Thus, the thermal influence of the wall heat transfer appears through its effect on the condensing length L*, so that at high condensation rates the pool is all liquid, and at low rates overflows (the level swell or foaming effect). Similarly, the phase separation effect hydrodynamically determines the height via the relative velocity of the mixture to the entering flux. We examine some practical applications of this result to level swell in condensing flows, and also examine some limits in ideal cases

Re-distribution (condensation) of magnons in a ferromagnet under pumping

International Nuclear Information System (INIS)

Zvyagin, A.A.

2008-01-01

In recent years several experiments have been performed to study the Bose-Einstein condensation of quasiparticles, in particular, magnons in magnetically ordered systems. Recently the Bose-Einstein condensation of magnons was observed at room temperatures in a ferromagnetic film. A theory of the condensation (redistribution) of magnons under the conditions of pumping, which explains many features of that experiment, is presented. The use of the term 'Bose-Einstein condensation of magnons' is discussed

All welded titanium condenser adopted in atomic power plants

International Nuclear Information System (INIS)

Iwai, Nagao; Itabashi, Yukihiko

1980-01-01

Condensers in power plants are shell-and-tube type heat exchangers. Most condensers use seawater as a coolant. Their tube and tube Sheets have usually been made of brass, which resists corrosion but cannot completely prevent it; as a result, tubes sometimes corrode or erode, allowing seawater to leak into the turbine cycle. As is well known, titanium has almost complete corrosion resistance against seawater; for this reason titanium tubes have replaced brass ones in some condensers operating in Europe and the USA. Even in such condensers, though, the tube plates have still been made of brass, tightly fitted to the titanium tubes, and it has proved impossible to eliminate seawater leakage at the junctions between tubes and tube Sheets. In order to eliminate such leakage completely, the tube Sheets must be made of titanium too, and the tubes and plates must be welded together. However, the welding of titanium requires an extremely celan atmosphere, a condition very difficult to fulfill at power plant construction sites, and the use of whole welded titanium tube condensers has long been considered a practical impossibility. Such all-titanium welded condensers have now been successfully constructed and installed in two 600 MW fossil power plants and one 1100 MW nuclear power plant. This paper describes the techniques used, add in addition reviews the various materials that have been used in condenser tubes. (author)

Fermion masses through four-fermion condensates

Energy Technology Data Exchange (ETDEWEB)

Ayyar, Venkitesh [Department of Physics, Duke University,Science Drive, Durham, NC 27708 (United States); Chandrasekharan, Shailesh [Department of Physics, Duke University,Science Drive, Durham, NC 27708 (United States); Center for High Energy Physics, Indian Institute of Science,C.V. Raman Avenue, Bangalore, 560012 (India)

2016-10-12

Fermion masses can be generated through four-fermion condensates when symmetries prevent fermion bilinear condensates from forming. This less explored mechanism of fermion mass generation is responsible for making four reduced staggered lattice fermions massive at strong couplings in a lattice model with a local four-fermion coupling. The model has a massless fermion phase at weak couplings and a massive fermion phase at strong couplings. In particular there is no spontaneous symmetry breaking of any lattice symmetries in both these phases. Recently it was discovered that in three space-time dimensions there is a direct second order phase transition between the two phases. Here we study the same model in four space-time dimensions and find results consistent with the existence of a narrow intermediate phase with fermion bilinear condensates, that separates the two asymptotic phases by continuous phase transitions.

Assessment and improvement of condensation model in RELAP5/MOD3

Energy Technology Data Exchange (ETDEWEB)

Rho, Hui Cheon; Choi, Kee Yong; Park, Hyeon Sik; Kim, Sang Jae [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Lee, Sang Il [Korea Power Engineering Co., Inc., Seoul (Korea, Republic of)

1997-07-15

The objective of this research is to remove the uncertainty of the condensation model through the assessment and improvement of the various heat transfer correlations used in the RELAP5/MOD3 code. The condensation model of the standard RELAP5/MOD3 code is systematically arranged and analyzed. A condensation heat transfer database is constructed from the previous experimental data on various condensation phenomena. Based on the constructed database, the condensation models in the code are assessed and improved. An experiment on the reflux condensation in a tube of steam generator in the presence of noncondensable gases is planned to acquire the experimental data.

40 CFR 63.447 - Clean condensate alternative.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Clean condensate alternative. 63.447... alternative. As an alternative to the requirements specified in § 63.443(a)(1)(ii) through (a)(1)(v) for the... HAP emissions reductions achieved by this clean condensate alternative technology are equal to or...

The shear viscosity of a trapped Bose-condensed gas

International Nuclear Information System (INIS)

Shahzamanian, M.A.; Yavary, H.

2006-01-01

By obtaining Kubo formula type and using nonequilibrium Green's functions, we calculate the shear viscosity of a trapped Bose-condensed gas below and above the Bose-Einstein condensation temperature (T BEC ). The contributions of the interactions between condensate and noncondensate atoms and between noncondensate atoms take into account to the viscous relaxation time, by evaluating second order self-energies in Beliaev approximation

Pion condensation in symmetric nuclear matter

International Nuclear Information System (INIS)

Kabir, K.; Saha, S.; Nath, L.M.

1987-09-01

Using a model which is based essentially on the chiral SU(2)xSU(2) symmetry of the pion-nucleon interaction, we examine the possibility of pion condensation in symmetric nucleon matter. We find that the pion condensation is not likely to occur in symmetric nuclear matter for any finite value of the nuclear density. Consequently, no critical opalescence phenomenon is expected to be seen in the pion-nucleus interaction. (author). 20 refs

Vector condensate model of electroweak interactions

International Nuclear Information System (INIS)

Cynolter, G.; Pocsik, G.

1997-01-01

Motivated by the fact that the Higgs is not seen, a new version of the standard model is proposed where the scalar doublet is replaced by a vector doublet and its neutral member forms a nonvanishing condensate. Gauge fields are coupled to the new vector fields B in a gauge invariant way leading to mass terms for the gauge fields by condensation. The model is presented and some implications are discussed. (K.A.)

Use of steam condensate exchange process for recovery of deuterium from condensate of ammonia plant as adopted at Heavy Water Plant, Talcher (Paper No. 2.5)

International Nuclear Information System (INIS)

Saha, S.; Saha, P.

1992-01-01

This paper highlights the use of steam-condensate exchange system for recovery of deuterium from condensate of ammonia plant, which is adopted at Heavy Water Plant, Talcher. Deuterium concentration in the condensate leaving the steam-condensate exchange column can be brought down very close to the deuterium concentration in water thereby achieving practically complete deuterium recovery. (author). 2 tabs., 1 fig

Condensed matter applied atomic collision physics, v.4

CERN Document Server

Datz, Sheldon

1983-01-01

Applied Atomic Collision Physics, Volume 4: Condensed Matter deals with the fundamental knowledge of collision processes in condensed media.The book focuses on the range of applications of atomic collisions in condensed matter, extending from effects on biological systems to the characterization and modification of solids. This volume begins with the description of some aspects of the physics involved in the production of ion beams. The radiation effects in biological and chemical systems, ion scattering and atomic diffraction, x-ray fluorescence analysis, and photoelectron and Auger spectrosc

Investigation of the condensing vapor bubble behavior through CFD simulation

International Nuclear Information System (INIS)

Sablania, Sidharth; Verma, Akash; Goyal, P.; Dutta, Anu; Singh, R.K.

2013-09-01

In nuclear systems the sub-cooled boiling flow is an important problem due to the behavior of condensing vapor bubble which has a large effect on the heat transfer characteristics as well as pressure drops and flow instability. The sub-cooled boiling flows become very complex and dynamic phenomena by the vapor bubble-water interaction. This happens due to the boiling/condensation, break-up, and coalescence of the bubble and needs to be addressed for characterizing the above mentioned flow parameters. There have been many researches to analyze the behavior of bubble experimentally and analytically. However, it is very difficult to get complete information about the behavior of bubble because of ever changing interface between vapor and water phase due to bubble condensation/evaporation Therefore, it is necessary to carry out a CFD simulation for better understanding the complex phenomenon of the bubble behavior. The present work focuses on the simulation of condensing bubble in subcooled boiling flow using (Volume of Fluid) VOF method in the CFD code CFD-ACE+. In order to simulate the heat and mass transfer through the bubble interface, CFD modeling for the bubble condensation was developed by modeling the source terms in the governing equations of VOF model using the User-Defined Function (UDF) in CFD-ACE+ code. The effect of condensation on bubble behavior was analyzed by comparing the behavior of condensing bubble with that of adiabatic bubble. It was observed that the behavior of condensing bubble was different from that of non condensing bubble in respect of bubble shape, diameter, velocity etc. The results obtained from the present simulation in terms of various parameters such as bubble velocity, interfacial area and bubble volume agreed well with the reported experimental results verified with FLUENT code in available literature. Hence, this CFD-ACE+ simulation of single bubble condensation will be a useful computational fluid dynamics tool for analyzing the

Reflux condensation behavior in SBLOCA tests of ATLAS facility

International Nuclear Information System (INIS)

Kim, Yeon-Sik; Park, Hyun-Sik; Cho, Seok; Choi, Ki-Yong; Kang, Kyoung-Ho

2017-01-01

Highlights: • Behavior of a reflux condensation heat transfer was investigated for SBLOCA tests. • Behavior of the reflux condensate in HL, SG inlet plenum, and U-tubes were evaluated. • Concept of a steam moisturizing phenomenon was introduced and discussed. • Test data and MARS calculations were compared and discussed on the reflux condensate. - Abstract: The behavior of the reflux condensation heat transfer in a hot side steam generator (SG) U-tubes during a cold leg (CL) pipe and a direct vessel injection (DVI) line break in small break loss-of-coolant accident (SBLOCA) tests of the ATLAS facility was investigated including MARS code calculations. Among the SBLOCA tests, a 6″-CL pipe and 50%-DVI line break SBLOCA test were selected to investigate the behavior of the reflux condensation. A reflux condensation heat transfer seemed to occur from the time the SG U-tubes were half-empty to near the loop seal clearing (LSC). It was found that a transition regime existed between the reflux condensation heat transfer and reverse heat transfer. The remaining reflux condensate in SG U-tubes owing to the counter-current flow limit (CCFL) phenomenon and a separating effect of liquid carry-over and/or entrainment with steam moisturizing seemed to affect the thermal-hydraulic behavior of the transition regime. It was also found that the steam flowrate of the loop pipings and SG U-tubes seemed to have a strong effect on the duration time of the transition regime, e.g., a larger steam flowrate results in a longer duration. From a comparison of the reflux condensation behavior between the ATLAS tests and MARS code calculations, overall qualitative agreements were found between the two cases. The largest discrepancies were found in the SG inlet plenum water level between the two cases, and the authors suggest that the combination effects of the remaining reflux condensate in SG U-tubes and a separating effect of liquid carry-over and/or entrainment with steam

Characterizing DNA condensation and conformational changes in organic solvents.

Directory of Open Access Journals (Sweden)

Fuyou Ke

Full Text Available Organic solvents offer a new approach to formulate DNA into novel structures suitable for gene delivery. In this study, we examined the in situ behavior of DNA in N, N-dimethylformamide (DMF at low concentration via laser light scattering (LLS, TEM, UV absorbance and Zeta potential analysis. Results revealed that, in DMF, a 21bp oligonucleotide remained intact, while calf thymus DNA and supercoiled plasmid DNA were condensed and denatured. During condensation and denaturation, the size was decreased by a factor of 8-10, with calf thymus DNA forming spherical globules while plasmid DNA exhibited a toroid-like conformation. In the condensed state, DNA molecules were still able to release the counterions to be negatively charged, indicating that the condensation was mainly driven by the excluded volume interactions. The condensation induced by DMF was reversible for plasmid DNA but not for calf thymus DNA. When plasmid DNA was removed from DMF and resuspended in an aqueous solution, the DNA was quickly regained a double stranded configuration. These findings provide further insight into the behavior and condensation mechanism of DNA in an organic solvent and may aid in developing more efficient non-viral gene delivery systems.

Polymorphism of Lysozyme Condensates.

Science.gov (United States)

Safari, Mohammad S; Byington, Michael C; Conrad, Jacinta C; Vekilov, Peter G

2017-10-05

Protein condensates play essential roles in physiological processes and pathological conditions. Recently discovered mesoscopic protein-rich clusters may act as crucial precursors for the nucleation of ordered protein solids, such as crystals, sickle hemoglobin polymers, and amyloid fibrils. These clusters challenge settled paradigms of protein condensation as the constituent protein molecules present features characteristic of both partially misfolded and native proteins. Here we employ the antimicrobial enzyme lysozyme and examine the similarities between mesoscopic clusters, amyloid structures, and disordered aggregates consisting of chemically modified protein. We show that the mesoscopic clusters are distinct from the other two classes of aggregates. Whereas cluster formation and amyloid oligomerization are both reversible, aggregation triggered by reduction of the intramolecular S-S bonds is permanent. In contrast to the amyloid structures, protein molecules in the clusters retain their enzymatic activity. Furthermore, an essential feature of the mesoscopic clusters is their constant radius of less than 50 nm. The amyloid and disordered aggregates are significantly larger and rapidly grow. These findings demonstrate that the clusters are a product of limited protein structural flexibility. In view of the role of the clusters in the nucleation of ordered protein solids, our results suggest that fine-tuning the degree of protein conformational stability is a powerful tool to control and direct the pathways of protein condensation.

Condensation of exciton polaritons

International Nuclear Information System (INIS)

Kasprzak, J.

2006-10-01

Because of their unique property of bringing pure quantum effects into the real world scale, phase transitions towards condensed phases - like Bose-Einstein condensation (BEC), superfluidity, and superconductivity - have always fascinated scientists. The BEC, appearing upon cooling a gas of bosons below a critical temperature, has been given a striking demonstration in dilute atomic gases of rubidium atoms at temperatures below 200 nK. By confining photons in a semiconductor micro-cavity, and strongly coupling them to electronic excitations, one may create polaritons. These bosonic quasi-particles are 10 9 times lighter than rubidium atoms, thus theoretically allowing a BEC at standard cryogenic temperatures. Here we detail a comprehensive set of experiments giving compelling evidence for a BEC of polaritons. Above a critical density, we observe massive occupation of the ground state, developing from a thermalized and saturated distribution of the polariton population at (16-20) K. We demonstrate as well the existence of a critical temperature for this transition. The spontaneous onset of a coherent state is manifested by the increase of temporal coherence, the build-up of long-range spatial coherence and the reduction of the thermal noise observed in second order coherence experiments. The marked linear polarization of the emission from the condensate is also measured. All of these findings indicate the spontaneous onset of a macroscopic quantum phase. (author)

Quantum condensates and topological bosons in coupled light-matter excitations

Energy Technology Data Exchange (ETDEWEB)

Janot, Alexander

2016-02-29

Motivated by the sustained interest in Bose Einstein condensates and the recent progress in the understanding of topological phases in condensed matter systems, we study quantum condensates and possible topological phases of bosons in coupled light-matter excitations, so-called polaritons. These bosonic quasi-particles emerge if electronic excitations (excitons) couple strongly to photons. In the first part of this thesis a polariton Bose Einstein condensate in the presence of disorder is investigated. In contrast to the constituents of a conventional condensate, such as cold atoms, polaritons have a finite life time. Then, the losses have to be compensated by continued pumping, and a non-thermal steady state can build up. We discuss how static disorder affects this non-equilibrium condensate, and analyze the stability of the superfluid state against disorder. We find that disorder destroys the quasi-long range order of the condensate wave function, and that the polariton condensate is not a superfluid in the thermodynamic limit, even for weak disorder, although superfluid behavior would persist in small systems. Furthermore, we analyze the far field emission pattern of a polariton condensate in a disorder environment in order to compare directly with experiments. In the second part of this thesis features of polaritons in a two-dimensional quantum spin Hall cavity with time reversal symmetry are discussed. We propose a topological invariant which has a nontrivial value if the quantum spin Hall insulator is topologically nontrivial. Furthermore, we analyze emerging polaritonic edge states, discuss their relation to the underlying electronic structure, and develop an effective edge state model for polaritons.

Evaluation of Advanced Models for PAFS Condensation Heat Transfer in SPACE Code

Energy Technology Data Exchange (ETDEWEB)

Bae, Byoung-Uhn; Kim, Seok; Park, Yu-Sun; Kang, Kyung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Ahn, Tae-Hwan; Yun, Byong-Jo [Pusan National University, Busan (Korea, Republic of)

2015-10-15

The PAFS (Passive Auxiliary Feedwater System) is operated by the natural circulation to remove the core decay heat through the PCHX (Passive Condensation Heat Exchanger) which is composed of the nearly horizontal tubes. For validation of the cooling and operational performance of the PAFS, PASCAL (PAFS Condensing Heat Removal Assessment Loop) facility was constructed and the condensation heat transfer and natural convection phenomena in the PAFS was experimentally investigated at KAERI (Korea Atomic Energy Research Institute). From the PASCAL experimental result, it was found that conventional system analysis code underestimated the condensation heat transfer. In this study, advanced condensation heat transfer models which can treat the heat transfer mechanisms with the different flow regimes in the nearly horizontal heat exchanger tube were analyzed. The models were implemented in a thermal hydraulic safety analysis code, SPACE (Safety and Performance Analysis Code for Nuclear Power Plant), and it was evaluated with the PASCAL experimental data. With an aim of enhancing the prediction capability for the condensation phenomenon inside the PCHX tube of the PAFS, advanced models for the condensation heat transfer were implemented into the wall condensation model of the SPACE code, so that the PASCAL experimental result was utilized to validate the condensation models. Calculation results showed that the improved model for the condensation heat transfer coefficient enhanced the prediction capability of the SPACE code. This result confirms that the mechanistic modeling for the film condensation in the steam phase and the convection in the condensate liquid contributed to enhance the prediction capability of the wall condensation model of the SPACE code and reduce conservatism in prediction of condensation heat transfer.

Evaporation and condensation at a liquid surface. II. Methanol

Science.gov (United States)

Matsumoto, Mitsuhiro; Yasuoka, Kenji; Kataoka, Yosuke

1994-11-01

The rates of evaporation and condensation of methanol under the vapor-liquid equilibrium condition at the temperature of 300 and 350 K are investigated with a molecular dynamics computer simulation. Compared with the argon system (reported in part I), the ratio of self-reflection is similar (˜10%), but the ratio of molecule exchange is several times larger than the argon, which suggests that the conventional assumption of condensation as a unimolecular process completely fails for associating fluids. The resulting total condensation coefficient is 20%-25%, and has a quantitative agreement with a recent experiment. The temperature dependence of the evaporation-condensation behavior is not significant.

Prótese intra-ocular de resina acrílica em cães e gatos Acrylic resin intraocular prosthesis in dogs and cats

Directory of Open Access Journals (Sweden)

S.C. Rahal

2000-08-01

Full Text Available Foram atendidos no Hospital Veterinário da Faculdade de Medicina Veterinária e Zootecnia da Unesp - Campus de Botucatu, 11 animais (oito cães e três gatos, com alterações oftálmicas unilaterais graves que levaram à perda total da função ocular (protrusão de globo com injúria nervosa e estrutural, perfurações de córnea com perda de conteúdo intra-ocular e endoftalmites, entre outras. Os animais, com idades entre dois meses e 10 anos, foram submetidos à evisceração e posterior inclusão de esfera de resina acrílica (metilmetacrilato na capa córneo-escleral ou escleral. As esferas foram previamente confeccionadas e esterilizadas por autoclavagem. No pós-operatório foram utilizados antiinflamatórios e antibioticoterapia tópica combinada ou não a sistêmica. O período de observação variou de 2 meses a 3 anos e os aspectos avaliados foram secreção ocular, blefarospasmo, sinais de desconforto e estética. Obtiveram-se resultados satisfatórios em oito casos. Concluiu-se que a resina acrílica pode ser uma alternativa para uso como inclusão em cavidade anoftálmica.Eleven animals (eight dogs and three cats, aged between two months and ten years were referred to the Veterinary Hospital of Faculty of Veterinary Medicine and Animal Science - Unesp, Botucatu, Brazil. These animals presented severe unilateral ophthalmic changes that lead to a total loss of ocular function, such as prolapsed eyes with nervous and structural injury, corneal damage with loss of intraocular contents or endophthalmitis among others. They were submitted to evisceration followed by the insertion of an acrylic resin prosthesis (methylmethacrylate in the corneoscleral or scleral shell. The spheres were previously made and sterilized by autoclave. The postoperative medical therapy included topical and systemic broad-spectrum antibiotics for seven days and anti-inflammatory drugs. The follow-up time varied from two months to three years. The evaluated

Preoperational test report, recirculation condenser cooling systems

Energy Technology Data Exchange (ETDEWEB)

Clifton, F.T.

1997-11-04

This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

Preoperational test report, recirculation condenser cooling systems

International Nuclear Information System (INIS)

Clifton, F.T.

1997-01-01

This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System

Conditioned random walks and interaction-driven condensation

International Nuclear Information System (INIS)

Szavits-Nossan, Juraj; Evans, Martin R; Majumdar, Satya N

2017-01-01

We consider a discrete-time continuous-space random walk under the constraints that the number of returns to the origin (local time) and the total area under the walk are fixed. We first compute the joint probability of an excursion having area a and returning to the origin for the first time after time τ . We then show how condensation occurs when the total area constraint is increased: an excursion containing a finite fraction of the area emerges. Finally we show how the phenomena generalises previously studied cases of condensation induced by several constraints and how it is related to interaction-driven condensation which allows us to explain the phenomenon in the framework of large deviation theory. (paper)

A simple air-cooled reflux condenser for laboratory use

International Nuclear Information System (INIS)

Boult, K.A.

1979-10-01

This Memorandum describes the design of a simple compact air-cooled reflux condenser suitable for gloveboxes, cells or other locations where the provision of cooling water presents a problem. In a typical application the condenser functioned satisfactorily when used to condense water from a flask heated by a 100 watt mantle. There was no measurable loss of water from the boiling flask in 100 hours. (author)

Diagnosis of condensation-induced waterhammer: Methods and background

International Nuclear Information System (INIS)

Izenson, M.G.; Rothe, P.H.; Wallis, G.B.

1988-10-01

This guidebook provides reference material and diagnostic procedures concerning condensation-induced waterhammer in nuclear power plants. Condensation-induced waterhammer is the most damaging form of waterhammer and its diagnosis is complicated by the complex nature of the underlying phenomena. In Volume 1, the guidebook groups condensation-induced waterhammers into five event classes which have similar phenomena and levels of damage. Diagnostic guidelines focus on locating the event center where condensation and slug acceleration take place. Diagnosis is described in three stages: an initial assessment, detailed evaluation and final confirmation. Graphical scoping analyses are provided to evaluate whether an event from one of the event classes could have occurred at the event center. Examples are provided for each type of waterhammer. Special instructions are provided for walking down damaged piping and evaluating damage due to waterhammer. To illustrate the diagnostic methods and document past experience, six case studies have been compiled in Volume 2. These case studies, based on actual condensation-induced waterhammer events at nuclear plants, present detailed data and work through the event diagnosis using the tools introduced in the first volume. 65 figs., 8 tabs

Condensed matter physics

International Nuclear Information System (INIS)

1990-01-01

This is a summary of condensed matter physics in Brazil. It discusses as well, the perspectives and financing evolved in this research area for the next decade. It is specially concerned with semiconductors, magnetic materials, superconductivity, polymers, glasses, crystals ceramics, statistical physics, magnetic resonance and Moessbauer spectroscopy. (A.C.A.S.)

Nucleation and condensation in the primitive solar nebula

International Nuclear Information System (INIS)

Cameron, A.G.W.; Fegley, M.B.

1982-01-01

It is pointed out that the primitive solar nebula may be modeled using the frictionally induced transport theory of Lynden-Bell and Pringle (1974) if the principal frictional mechanism within the nebula is turbulent viscosity. The present investigation is concerned with the construction of a model of a section of the primitive solar nebula as a basis for the study of nucleation and condensation processes within this section. The construction involves a relatively simple application of the Lynden-Bell and Pringle theory subject to steady mass flow conditions. The calculations which are conducted in connection with the investigation indicate that by the time the gas in the primitive solar nebula has become sufficiently supercooled to nucleate condensation centers, several different compounds, including the magnesium silicates forsterite and enstatite (MgSiO 3 ), will probably be able to condense on the growing condensation center

1D models for condensation induced water hammer in pipelines

International Nuclear Information System (INIS)

Bloemeling, Frank; Neuhas, Thorsten; Schaffrath, Andreas

2013-01-01

Condensation induced water hammer (CIWH) are caused by contact of steam and subcooled water. Thus, modeling the direct contact condensation is a crucial step towards the simulation of condensation induced water hammer with 1D pressure surge codes. Therefore, also the TUeV NORD SysTec GmbH and Co. KG inhouse pressure surge code DYVRO has been equipped with a new contact condensation model. The validation of DYVRO against an experiment dealing with CIWH is presented in this contribution. (orig.)

1D models for condensation induced water hammer in pipelines

Energy Technology Data Exchange (ETDEWEB)

Bloemeling, Frank; Neuhas, Thorsten; Schaffrath, Andreas [TUEV NORD SysTec GmbH und Co. KG, Hamburg (Germany)

2013-03-15

Condensation induced water hammer (CIWH) are caused by contact of steam and subcooled water. Thus, modeling the direct contact condensation is a crucial step towards the simulation of condensation induced water hammer with 1D pressure surge codes. Therefore, also the TUeV NORD SysTec GmbH and Co. KG inhouse pressure surge code DYVRO has been equipped with a new contact condensation model. The validation of DYVRO against an experiment dealing with CIWH is presented in this contribution. (orig.)

Collision of Bose Condensate Dark Matter structures

International Nuclear Information System (INIS)

Guzman, F. S.

2008-01-01

The status of the scalar field or Bose condensate dark matter model is presented. Results about the solitonic behavior in collision of structures is presented as a possible explanation to the recent-possibly-solitonic behavior in the bullet cluster merger. Some estimates about the possibility to simulate the bullet cluster under the Bose Condensate dark matter model are indicated.

Hydrophilic structures for condensation management in appliances

Science.gov (United States)

Kuehl, Steven John; Vonderhaar, John J.; Wu, Guolian; Wu, Mianxue

2016-02-02

An appliance that includes a cabinet having an exterior surface; a refrigeration compartment located within the cabinet; and a hydrophilic structure disposed on the exterior surface. The hydrophilic structure is configured to spread condensation. The appliance further includes a wicking structure located in proximity to the hydrophilic structure, and the wicking structure is configured to receive the condensation.

Development of a condenser for the dual catalyst water recovery system

Science.gov (United States)

Budinikas, P.; Rasouli, F.; Rabadi, N.

1983-01-01

Conceptual evaporation/condensation systems suitable for integration with the catalytic water recovery method were evaluated. The primary requirements for each concept were its capability to operate under zero-gravity conditions, condense recovered water from a vapor-noncondensable gas mixture, and integrate with the catalytic system. Specific energy requirements were estimated for concepts meeting the primary requirements, and the concept most suitable for integration with the catalytic system was proposed. A three-man rate condenser capable of integration with the proposed system, condensing water vapor in presence of noncondensables and transferring the heat of condensation to feed urine was designed, fabricated, and tested. It was treated with steam/air mixtures at atmospheric and elevated pressures and integrated with an actual catalytic water recovery system. The condenser has a condensation efficiency exceeding 90% and heat transfer rate of approximately 85% of theoretical value at coolant temperature ranging from 7 to 80 deg C.

Investigating tunable KRb gases and Bose-Einstein condensates

DEFF Research Database (Denmark)

Jørgensen, Nils Byg

2015-01-01

We present the production of dual-species Bose-Einstein condensates of 39K and 87Rb with tunable interactions. A dark spontaneous force optical trap was used for 87Rb to reduce the losses in 39K originating from light-assisted collisions in the magneto optical trapping phase. Using sympathetic...... for dual-species condensates with tunable interactions. Employing the dual-species condensates, the miscible to immiscible phase transition was investigated. By applying an empirical model, the transition was used to determine the background scattering length. Two species quantum gases with tunable...

Condensation induced water hammer in steam supply system

International Nuclear Information System (INIS)

Andrews, P.B.; Antaki, G.A.; Rawls, G.B.; Gutierrez, B.J.

1995-01-01

The accidental mixing of steam and water usually leads to condensation induced water hammer. This phenomenon is not uncommon in the power and process industries, and is of particular concern due to the high energies which accompany steam transients. The paper discusses the conditions which lead to a recent condensation induced water hammer in a 150 psig steam supply header. The ensuing structural damage, inspection and repairs are described. Finally, a list of design, maintenance and operational cautions are presented to help minimize the potential for condensation induced water hammer in steam lines

Condensation induced water hammer in steam supply system

International Nuclear Information System (INIS)

Andrews, P.B.; Antaki, G.A.; Rawls, G.B.; Gutierrez, B.J.

1995-01-01

The accidental mixing of steam and water usually leads to condensation induced water hammer. THis phenomenon is not uncommon in the power and process industries, and is of particular concern due to the high energies which accompany steam transients. The paper discusses the conditions which lead to a recent condensation induced water hammer in a 150 psig steam supply header. The insuing structural damage, inspection and repairs are described. Finally, a list of design cautions are presented to help minimize the potential for condensation induced water hammer in steam lines

Method for extending the unrestricted operating range of condensing steam turbines

International Nuclear Information System (INIS)

Csaba, G.; Bannerth, Cs.

2009-01-01

The allowed condenser temperature of the condensing steam turbines is determined by the design parameters of the steam turbine (casing geometry, exhaust area, blade length, blade angle, blade profile etc.). The fluctuations of condenser temperature may lead to reduced power output of the condensing steam turbine. Solutions where the low pressure turbine casings have the same exhaust area can be kept in operation at narrow condenser temperature range without restrictions. Exceeding the mentioned temperature range the exhaust hood temperature restriction, undergoing the temperature range choking point restriction appears causing increased operation cost. The aim of the paper is to present a condensing steam turbine - direct-contact condenser system that can extend the unrestricted operating range. The examined system consists of more parallelly connected low pressure turbine casings so-called diabolo that having at least two exhausts separated at the steam side. The exhausts, utilizing varying input-temperature coolant, are connected to the condensers that are separated at the steam side and serially connected at the coolant side. The casings have the same inlet areas while the exhausts have different areas resulting different volume flows and temperature operating range. The economic advantage of this solution approaches the savings between the serially connected direct-contact condensers and condensers in parallel of a dry cooling system. It can be proven by a simple calculation using the ambient air temperature duration diagram that is presented in the paper. (author)

An analysis of some basic studies on the condensation in the presence of non-condensable along a plane plate

International Nuclear Information System (INIS)

Vernier, P.; Dalbe, M.

1984-01-01

Our study aims at facilitating the calculation of vapour condensation rate in the containment vessel of a PWR system in the event of a LOCA. Emphasis is placed on filmwise condensation because of its prime importance in such events. We have restricted ourselves to the steady-state regimes. The previous studies consider a laminar film, coupled with a vapour-air mixture laminar boundary layer, which are developed under the action of body and/or pressure forces. It has been show that, depending on the air mass fraction, the condensation rate reduces drastically as a result of the diffusion phenomena. Moreover the effects of the vapour superheating have been discussed. When film and/or boundary layer are turbulents, there is no satisfactory theory but only experimental correlations. Owing to the effect of suction (condensation), the correlations for the various transfers from the boundary layer must be corrected by some factors stemming from the ''film theory''. One should be able to treat the coupling between the turbulent film and the boundary layer by the integral method [fr

Improvements to TRAC models of condensing stratified flow. Pt. 1

International Nuclear Information System (INIS)

Zhang, Q.; Leslie, D.C.

1991-12-01

Direct contact condensation in stratified flow is an important phenomenon in LOCA analyses. In this report, the TRAC interfacial heat transfer model for stratified condensing flow has been assessed against the Bankoff experiments. A rectangular channel option has been added to the code to represent the experimental geometry. In almost all cases the TRAC heat transfer coefficient (HTC) over-predicts the condensation rates and in some cases it is so high that the predicted steam is sucked in from the normal outlet in order to conserve mass. Based on their cocurrent and countercurrent condensing flow experiments, Bankoff and his students (Lim 1981, Kim 1985) developed HTC models from the two cases. The replacement of the TRAC HTC with either of Bankoff's models greatly improves the predictions of condensation rates in the experiment with cocurrent condensing flow. However, the Bankoff HTC for countercurrent flow is preferable because it is based only on the local quantities rather than on the quantities averaged from the inlet. (author)

Heat Transfer Enhancement During Water and Hydrocarbon Condensation on Lubricant Infused Surfaces.

Science.gov (United States)

Preston, Daniel J; Lu, Zhengmao; Song, Youngsup; Zhao, Yajing; Wilke, Kyle L; Antao, Dion S; Louis, Marcel; Wang, Evelyn N

2018-01-11

Vapor condensation is routinely used as an effective means of transferring heat or separating fluids. Dropwise condensation, where discrete droplets form on the condenser surface, offers a potential improvement in heat transfer of up to an order of magnitude compared to filmwise condensation, where a liquid film covers the surface. Low surface tension fluid condensates such as hydrocarbons pose a unique challenge since typical hydrophobic condenser coatings used to promote dropwise condensation of water often do not repel fluids with lower surface tensions. Recent work has shown that lubricant infused surfaces (LIS) can promote droplet formation of hydrocarbons. In this work, we confirm the effectiveness of LIS in promoting dropwise condensation by providing experimental measurements of heat transfer performance during hydrocarbon condensation on a LIS, which enhances heat transfer by ≈450% compared to an uncoated surface. We also explored improvement through removal of noncondensable gases and highlighted a failure mechanism whereby shedding droplets depleted the lubricant over time. Enhanced condensation heat transfer for low surface tension fluids on LIS presents the opportunity for significant energy savings in natural gas processing as well as improvements in thermal management, heating and cooling, and power generation.

Condensing heat transfer following a loss-of-coolant accident