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Sample records for metal expandido sometidas

  1. O uso de politetrafluoroetileno expandido em tireoplastia tipo I

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    Mello-Filho Francisco Veríssimo de

    2003-01-01

    Full Text Available A paralisia unilateral de prega vocal (PUPV em abdução é uma alteração que produz grande desconforto ao paciente, principalmente pelos distúrbios fonatórios causados. Atualmente dispomos de uma variedade de métodos para seu tratamento. OBJETIVO: Verificar a eficiência, vantagens e desvantagens do uso da fita de politetrafluoretileno expandido (PTFE-e, na medialização de prega vocal (PV paralisada, em abdução. FORMA DE ESTUDO: Coorte Longitudinal. MATERIAL E MÉTODOS: Foram estudados quatro pacientes com diagnóstico clínico-laringoscópico de disfonia por PPVU, em abdução há pelo menos um ano. Os pacientes foram submetidos a avaliação fonoaudiológica e a tireoplastia tipo I para medialização da PV com fita de PTFE-e. Durante o seguimento pós-operatório procedeu-se videolaringoscopia, tomografia computadorizada e fonoterapia. RESULTADOS: Todos os pacientes estão satisfeitos com a qualidade vocal, apresentam medialização estável da PV com a fonocirurgia e bons resultados à avaliação fonoaudiológica. Um paciente apresentou extrusão intra-operatória da fita de PTFE-e, sendo feito um segundo procedimento, sem complicações, seis meses depois. CONCLUSÃO: Na opinião dos autores a fita de PTFE-e se presta com eficiência ao tratamento da PUPV, sem apresentar riscos importantes.

  2. Dolor postoperatorio en mujeres sometidas a cesárea

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    Borges, Natalia Carvalho; Silva, Brunna Costa e; Pedroso, Charlise Fortunato; Silva, Tuany Cavalcante; Tatagiba, Brunna Silva Ferreira; Pereira, Lílian Varanda

    2017-01-01

    RESUMEN Objetivo Estimar la incidencia, intensidad y calidad del dolor postoperatorio en mujeres sometidas a cesárea. Método Estudio de corte transversal. Fueron entrevistadas 1062 mujeres sometidas a cesárea en el periodo pre y post cirugía inmediatos. La intensidad del dolor y la calidad fueron evaluadas por la Escala Numérica del Dolor (0-10) y el Test de Dolor de McGill. Las variables se analizaron utilizando medidas descriptivas y la incidencia de dolor postoperatorio calculado con u...

  3. Produtos extrusados expandidos de misturas de canjiquinha e soja para uso como petiscos

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    Fernandes Marilene dos Santos

    2002-01-01

    Full Text Available O objetivo deste trabalho foi estudar o efeito da temperatura de barril (TB do extrusor no índice de expansão (IE e no índice de solubilidade em água (ISA dos produtos extrusados expandidos de misturas de canjiquinha e soja (80:20 e 70:30, e verificar suas características sensoriais, quando aromatizado para uso como petiscos. Foi usado o extrusor Brabender de dupla-rosca, com velocidade de alimentação constante de 20,8 kg/h, velocidade da rotação de parafuso de 100 rpm e diâmetro de matriz de 5 mm. As temperaturas de barril do extrusor foram constantes na zona 1 (60masculineC e na zona 2 (90masculineC e variáveis na zona 3 (90, 110, 130 e 150masculineC e na zona 4 (110, 130 e 150masculineC. O IE e o ISA dos produtos extrusados expandidos aumentaram com o aumento da TB na zona 3 até 110masculineC; acima desta temperatura, observou-se diminuição desses índices. O aumento da TB na zona 4 resultou em aumento no IE e ISA, exceto quando os produtos haviam sido submetidos a 130 e 150masculineC na zona 3. O produto extrusado expandido contendo 80% de canjiquinha e 20% de soja, submetido às temperaturas de barril de 60, 90, 110 e 150masculineC e aromatizado com cebola, apresentou melhor aparência, textura e sabor, e foi preferido pelos consumidores. Não houve atividade do inibidor de tripsina nos produtos estudados.

  4. Produtos extrusados expandidos de misturas de canjiquinha e soja para uso como petiscos.

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    FERNANDES, M. dos S.; WANG, S.; ASCHERI, J.L.R.; OLIVEIRA, M.F. de; COSTA, S.A.J.

    2003-01-01

    O objetivo deste trabalho foi estudar o efeito da temperatura de barril (TB) do extrusor no índice de expansão (IE) e no índice de solubilidade em água (ISA) dos produtos extrusados expandidos de misturas de canjiquinha e soja (80:20 e 70:30), e verificar suas características sensoriais, quando aromatizado para uso como petiscos. Foi usado o extrusor Brabender de dupla-rosca, com velocidade de alimentação constante de 20,8 kg/h, velocidade da rotação de parafuso de 100 rpm e diâmetro de matri...

  5. Perspectiva de uso del poliestireno expandido, como alternativa de impermeabilizante, para electrodos empleados en la soldadura subacuática mojada

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    Lorenzo Perdomo González

    2012-01-01

    Full Text Available La soldadura subacuática mojada, usando el proceso manual con electrodorevestido (SMAW, es actualmente la técnica más empleada para realizar trabajos de reparación en condiciones subacuática (mojada, debido a las características de maniobrabilidad propias del proceso. El revestimiento es la parte estructural del electrodo que más influye sobre su campo de aplicación, por tanto su impermeabilización es requisito indispensable, la cual se realiza mediante la aplicación de capas impermeables sobre el mismo, utilizándose habitualmente para esta operación resinas, ceras, parafinas o barnices. En eltrabajo se presenta una evaluación preliminar, acerca del uso del poliestireno reciclado como alternativa para la fabricación de un impermeabilizante para estos electrodos, abordándose las características principales de su preparación y forma de aplicación. Para realizar la evaluación de este nuevo impermeabilizante, se realizaron depósitos de soldadura en lámina de aguay a 50 m de profundidad, comparándose el desempeño de los electrodos impermeabilizados con el barniz tradicional y con la nueva formulación, fundamentalmente en lo referido a la apariencia superficial del cordón y a la formación de poros en el metal depositado a 50 m de profundidad, además fue realizada la caracterización química a los depósitos obtenidos en lámina de agua. La evaluación preliminar evidenció la factibilidad de emplear el poliestireno expandido como material alternativo para la fabricación de impermeabilizante para los electrodos empleados en operaciones de soldadura subacuática mojada.

  6. Comunidades de atingidos, o comum e o dom expandido Affected communities, the ordinary and the expanded gift

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    Antonio Lafuente

    2011-07-01

    Full Text Available Este artigo examina a relação entre a tecnologia e os bens comuns e, a partir daí, propõe uma nova valência para o comum. O novo comum deve ser entendido como uma economia do dom que assiste, a cada novo ciclo de relações assimétricas, ao surgimento de uma questão que preocupa uma comunidade de afeto ou de atingidos. A economia do dom expandido retém a produtividade conceitual da famosa teoria do dom de Marcel Mauss, mas é adaptada a um mundo em que quem doa e quem recebe tendem a permanecer anônimos e as expectativas de retribuição, indefinidas. Finalmente, o artigo defende a noção de um dom expandido, cuja economia de reciprocidade possa, em um único gesto, fazer aparecer novas formas de comunidade e inaugurar protocolos inovadores de mobilização social.The article investigates the relationship between technology and ordinary goods in order to propose a new valence for the ordinary. The new ordinary should be understood as a gift economy that witnesses, within every new cycle of asymmetrical relations, the rise of a matter that regards a community of shared affections, or affected community. The expanded gift economy retains the conceptual productivity of Marcel Mauss’s famous theory about the gift, except that it is adapted to a world in which giver and receiver tend to remain anonymous, and the retribution expectations, undefined. At long last, the article argues for a notion of an expanded gift, whose reciprocity economy may - in a single gesture - make appear new forms of community and launch innovative social mobilization protocols.

  7. Incertidumbre, calidad de vida e imagen corporal en mujeres sometidas a mastectomía

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    Mejía Rojas, María Elena

    2012-01-01

    Estudio analítico, observacional, no experimental, correlacional, que analizó la relación entre incertidumbre, calidad de vida e imagen corporal con los instrumentos; (incertidumbre frente a la enfermedad Mishel 1988, calidad de vida en mujeres sobrevivientes al cáncer QOL Betty Ferrell 1995, y escala de imagen corporal de Hopwood 1983), en 76 mujeres sobrevivientes al cáncer de mama sometidas a mastectomía; con cirugía reconstructiva (37) y sin cirugía reconstructiva (39), de Cali Colombia e...

  8. Validación del KDRI/KPDI para la selección de donantes renales con criterios expandidos

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    Raimundo M García del Moral Martín

    2018-05-01

    Full Text Available Resumen: Introducción: El KDRI y su variante KDPI son dos herramientas utilizadas para la valoración del donante renal. Se ha propuesto la utilidad del KDPI como sustituto/complementario a la biopsia renal preimplantación. Estos scores no están validados en España. Objetivo: 1 Investigar la concordancia entre los scores KDPI e histológico (biopsia renal preimplantación, y 2 valorar la relación entre el KDRI, KDPI y la puntuación histológica sobre la supervivencia del injerto, en donantes con criterios expandidos (ECD. Metodología: Estudio de cohortes, unicéntrico, retrospectivo desde el 1 de enero de 1998 hasta el 31 de diciembre de 2010. Resultados: Se reclutaron 120 donantes y 220 biopsias preimplantación. Ciento cuarenta y cuatro (65,5% injertos fueron aptos para trasplante. Setenta y seis (34,5% fueron descartados. Tiempo medio de seguimiento 6,4 años (ds 3,9. Edad media de los donantes 63,1 años (ds 8,2, varones (145; 65,9%, no diabéticos (191; 86,8% y sin otros factores de riesgo cardiovascular (173; 78,6%. Causa de muerte mayoritaria ACV hemorrágico (153; 69,5%. La puntuación KDPI media entre los grupos riñón válido (1,56/89; ds 0,22 y no válido (1,66/93; ds 0,15 es estadísticamente significativa (p < 0,01. El KDPI mostró una concordancia y correlación moderadas con el score histológico (AUC 0,64/coeficiente de correlación 0,24, p < 0,01. Los scores KDPI (HR 24,3, p < 0,01 y KDRI (HR 23,3, p < 0,01 están relacionados con la supervivencia del injerto en el análisis multivariante. Conclusión: 1 Los scores KDPI e histológico presentan una concordancia moderada. 2 Las puntuaciones KDPI, y sobre todo KDRI, son válidas para estimar la supervivencia de los injertos y pueden ser utilizadas de forma combinada con la biopsia para la toma de decisiones individualizadas en el grupo de donantes con criterios expandidos. Abstract: Introduction: KDRI / KDPI are tools use in kidney donor evaluation. It has been proposed as

  9. EFEITOS DA TELA DE POLITETRAFLUOROETILENO EXPANDIDO COLOCADA NO ESPAÇO PRÉ-PERITONEAL POR VIDEOLAPAROSCOPIA EM SUÍNOS

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    Sandra Crippa Brandão

    1998-07-01

    Full Text Available Com o objetivo de observar os efeitos produzidos pela tela de politetrafluoroetileno expandido (PTFE-e, no espaço pré-peritoneal, foram utilizados 20 suínos (n=20 da raça Large White, todos machos, distribuídos em dois grupos de dez animais. A técnica operatória utilizada foi a videolaparoscopia transabdominal. De um lado, na região inguinal, o espaço pré-peritoneal foi dissecado e a tela fixada; na região contralateral, o procedimento foi o mesmo, sem a colocação da tela, servindo como controle. O peritônio parietal local foi aproximado com uma sutura contínua de poliglactina 910. A eutanásia foi realizada aos sete e vinte um dias de pós-operatório. No primeiro grupo, um animal apresentou aderência no local de implantação da tela e, no segundo grupo, um animal também apresentou aderência, mas no lado controle. Concluiu-se, baseado na presente pesquisa, que a tela de PTFE-e não provocou a formação de aderências, quando colocada no espaço pré-peritoneal em suínos.Twenty (20 Large White male pigs (n=20 divided in groups of ten were used to observe the effects produced by the use of expanded polytetrafluoroethylene (e-PTFE mesh, in the preperitoneal space. The operative approach was the laparoscopic transabdominal technique. On one side, in the inguinal region, the preperitoneal space was dissected and the mesh was fixed. On the other side, as a control, the same procedure has been done without the utilization of mesh. The local parietal peritoneum was approximated with a polyglactin 910 continuous suture. The animals were submitted to euthanasia at the 7th and the 21th days of postoperative evolution. In the first group, one animal presented adhesion formation where the mesh was placed and, in the second group, there was also one animal with adhesion formation but in the control side. It was concluded that e-PTFE mesh did not incited significant adhesion formation when placed in the preperitoneal space in a swine

  10. Comportamiento de la adherencia en menas lateríticas sometidas a secado solar natural

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    Naísma Hernández-Jatib

    2009-03-01

    Full Text Available El alto contenido de humedad de la mena laterítica provoca su adherencia a las paredes de las tolvas donde es almacenada y, por consiguiente, disminuye la cantidad alimentada a los secaderos e incrementa el consumo de combustible durante el secado térmico en los tambores rotarios. Para evaluar el comportamiento de la adherencia en menas sometidas a secado solar natural se estudiaron experimentalmente dos pilas expuestas a condiciones ambientales naturales. Los experimentos consistieron en verter (para valores conocidos de humedad 300 g de mena desde una altura de 0,5 m sobre una placa de cristal con distinta inclinación (20 y 25 grados. Se tamizaron las muestras de una de las pilas para evaluar la influencia de la granulometría sobre la adherencia. Se encontró que la adherencia de la mena no está determinada solamente por el contenido de humedad, sino además por su granulometría y por el ángulo de inclinación de la superficie de contacto. El menor porcentaje de adherencia para granulometría heterogénea se obtuvo para valores de humedad igual o inferior a 32%. También se evidenció que para contenido de humedad igual a 35% o mayor, el ángulo de inclinación de la superficie de contacto con la mena no influye notablemente en la adherencia cuando la mena es previamente tamizada.

  11. Comportamiento psicológico, social y familiar de la mujer sometida a mastectomía

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    Verdugo Sánchez, Adriana Elizabeth

    2007-01-01

    Determinar el comportamiento psicológico, social y familiar de la mujer sometida a mastectomía. Pregunta central: ¿Por qué para la mujer, la mama es tan fundamental? Se trabajó con las siguientes categorías: Noticia ante el diagnóstico de cáncer, mastectomía, impacto inmediato, conflictos tempranos, relaciones con la pareja, familia y entorno, respuestas a mediano plazo, visión de futuro. Material y Métodos: es un estudio cualitativo: fenomenológico y hermenéutico que utilizó el estudio ...

  12. Ventajas del colgajo frontal expandido para la reconstrucción nasal Advantages of the expanded frontal flap for nasal reconstruction

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    Julio César Gálvez Chávez

    2010-12-01

    Full Text Available INTRODUCCIÓN. Desde 1957 la expansión tisular se ha convertido en una técnica muy utilizada en cirugía reconstructiva, pues permite obtener gran cantidad de tejido blando para corregir defectos cutáneos. En Cuba se ha publicado muy poco sobre la utilización de expansores cutáneos de la región frontal para la reconstrucción nasal. El objetivo de este trabajo fue caracterizar la utilidad del colgajo frontal expandido, para la reconstrucción de defectos nasales distales de espesor total en pacientes con frente corta. MÉTODOS. Se realizó un estudio descriptivo, prospectivo, con pacientes con defectos nasales secundarios a cirugía oncológica, traumatismos y otras causas, a los que se les practicó una reconstrucción nasal con colgajo frontal expandido en el Instituto Nacional de Oncología y Radiobiología y el Hospital «Hermanos Ameijeiras», entre junio de 1999 y mayo de 2007. RESULTADOS. Hubo una ganancia promedio de 1,0 cm en longitud del colgajo frontal expandido con respecto al diseño oblicuo sin expansión. Se logró la reconstrucción de la cubierta cutánea en todos los casos, incluso en los defectos más distales, como los del ala nasal. El cierre de la zona donante siempre fue de forma directa. CONCLUSIONES. Se pudo caracterizar la utilidad del colgajo frontal expandido en la muestra estudiada y se encontró entre sus ventajas fundamentales la ganancia en longitud con respecto a la distancia vertical de la frente. Concordamos con la mayoría de los autores en cuanto a su utilidad, siempre que esté indicado y disponible, y en que es un recurso alternativo cuando existe poco tejido disponible para la reconstrucción de los defectos nasales.INTRODUCTION. From 1957, the tissues expansion has becomes a very used technique in reconstructive surgery, since allows to obtain abundant soft tissue to correct cutaneous defects. In Cuba there aren't much publications on the use of cutaneous expanders of frontal region to nasal

  13. Consenso expandido do BCTRIMS para o tratamento da esclerose múltipla: III. Diretrizes baseadas em evidências e recomendações

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    Lana-Peixoto Marco Aurélio

    2002-01-01

    Full Text Available Em razão dos avanços no conhecimento da esclerose múltipla (EM, dos novos critérios diagnósticos e ensaios terapêuticos publicados, a atualização e expansão das diretrizes para orientação do neurologista brasileiro em relação ao tratamento da EM se tornam necessárias. O Consenso Expandido do BCTRIMS enfatiza a individualização do tratamento a critério do neurologista, e a necessidade de informação do paciente quanto aos potenciais benefícios e riscos das drogas, assim como do Consentimento Informado e compromisso de realização de controles periódicos. Na ausência de evidências científicas favorecendo uma determinada droga o médico deve considerar o custo diferencial dos imunomoduladores ao fazer sua opção terapêutica. As várias situações clínicas e os diferentes agentes modificadores da doença, assim como as outras intervenções terapêuticas de eficácia no tratamento são consideradas à luz das classes de evidências científicas e dos tipos de recomendação, aceitos pela comunidade científica internacional. O Consenso Expandido do BCTRIMS pode servir de modelo para outros países em desenvolvimento.

  14. Identificación de las propiedades dinámicas de una estructura sometida a vibración ambiental empleando análisis espectral

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    Henao Ángel, David

    2013-01-01

    1 CD-ROM Se adopta una metodología basada en la teoría de procesos estocásticos para la determinación de frecuencias, formas modales y amortiguamientos de una estructura sometida a vibraciones ambientales. El procedimiento se lleva a cabo mediante el uso del análisis espectral, el cual utiliza espectros de potencia, funciones de transferencia, funciones de coherencia, entre otros, para describir el comportamiento de una estructura sometida a cualquier tipo de excitación. A partir del análi...

  15. Influencia del espesor de adhesivo de poliuretano en la resistencia de uniones sometidas a cortadura

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    García-Ledesma, R.

    2005-02-01

    Full Text Available The thickness of adhesive layers in metallic bonded joints has direct influence in the performance and mechanical behaviour of these joints. The aim of this study was to analyse the strength and strain properties of steel overlap joints bonded with polyurethane adhesive layers with different thickness. The results show that the strength is maximum when the thickness of the adhesive layer is very thin, 0.1 mm. When the thickness growth to 1 mm the strength goes down rapidly. For layers from 1 to 1.5 mm the strength goes down slower and from 1.5 to 4 mm the strength is nearly constant. In other hand, the joint strain increase uniformly with adhesive layer thickness growth.

    El espesor de la capa de adhesivo en las uniones por adhesión de materiales metálicos, tiene una influencia notable en el comportamiento y las propiedades mecánicas de dichas uniones. El objeto de este trabajo fue analizar las propiedades de resistencia y desplazamiento, presentadas por uniones a solape de acero, unidas con capas de diferentes espesores de un adhesivo de poliuretano. Los resultados obtenidos muestran que la resistencia mecánica es máxima para capas de adhesivo de espesor muy delgado: 0,1 mm. Cuando el espesor crece de 0,1 hasta 1 mm la resistencia disminuye rápidamente. Para capas desde 1 hasta 1,5 mm la resistencia disminuye más lentamente y, a partir de 1,5 mm, la resistencia permanece prácticamente constante. Por otro lado, los desplazamientos de la unión aumentan uniformemente a medida que crece el espesor de la capa de adhesivo.

  16. RECUENTO DE COLIFORMES Y Escherichia coli EN CANALES BOVINAS SOMETIDAS A TRATAMIENTOS FÍSICOS Y QUÍMICOS

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    EDUARDO JAVID CORPAS-IGUARÁN

    Full Text Available Se evaluó el recuento de coliformes totales y Escherichia coli en canales bovinas sometidas a diferentes tratamientos que incluyeron combinaciones de los métodos de lavado, desinfección y vaporización, utilizando el diseño completamente aleatorizado de un factor con 3 repeticiones. El muestreo se realizó mediante frotis de superficie en tres áreas diferentes de la muestra (espalda, pecho y anca, que fueron posteriormente analizadas mediante el método de recuento en placa. Al aplicar secuencialmente los métodos de remoción microbiana se apreció la disminución progresiva en el recuento de coliformes totales y E. coli, y en la variabilidad de los datos, principalmente en los tratamientos C, D y E. La prueba de contrastes múltiples de Friedman mostró la inexistencia de diferencias estadísticas entre los recuentos de los tratamientos C y E en la muestra 2, indicando la ineficacia de la vaporización como coadyuvante de la acidificación para disminuir el recuento de los microorganismos de estudio. Las pruebas de comparación en muestras independientes mostraron resultados idénticos a la prueba de Friedman, excepto para el recuento de E. coli entre los tratamientos D y E, sugiriendo que la vaporización tiene efecto significativo para potenciar la disminución del recuento del microorganismo en las canales.

  17. Mezclas de residuos de poliestireno expandido (EPS conglomerados con yeso o escayola para su uso en la construcción

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    González Madariaga, Francisco Javier

    2008-03-01

    Full Text Available This research project looks for to innovate in the management of expanded plastic materials wastes and to propose techniques that take advantage of the properties that those plastics still have at the time they are discarded to the urban wastes flow, such is the case of the expanded polystyrene wastes (EPS which after being transformed in small particles and mixed with pastes made of standard gypsum and water in diverse proportions allows the production of different construction products. At the end of this paper two specific mixtures are described; the first useful for gypsum wallboard production, and the second one to manufacture a flat board for thermal isolation material. The EPS is a stiff cell plastic material produced from the molding of little spheres or pearls of expansible polystyrene that shows a closed structure made of this thermoplastic which contains trapped air in a 96-98% proportion of the volume of the pearls. Packaging is one of the main applications for this material hence EPS is a plenty waste in our society, it is also very popular in building construction where it is installed in air wall cameras and indoors covers; finally in a small proportion the plastic has other kind of applications like sport protections and commercial display.Se ha logrado ofrecer un grupo de 8 propuestas concretas para reciclaje de poliestireno expandido (EPS que consiste en mezclar yeso o escayola y agua para constituir pastas que contienen residuos de EPS que se moldean como placas y paneles para la construcción. Se ha ensayado con muestras de pastas que van desde aquellas que contienen proporciones extremas de residuos hasta otras donde la presencia de agua para la preparación de las mezclas es inusualmente rica, también se han ensayado mezclas compuestas por proporciones intermedias de sus ingredientes. De las pastas con los mejores comportamientos en ensayos previos se han aplicado sus fórmulas en la fabricación de muestras de placas y

  18. La brecha de la “complejidad”: perfil eAprendiz como propuesta de adecuación personal al nuevo entorno “vital”, expandido y complejo

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    Rubio Royo, Enrique

    2011-12-01

    ón con un nivel de interconexión e interdependencia sin precedentes (causa de su complejidad, con nuevas estructuras (redes y con nuevas tecnologías sociales, que configuran a Internet como infraestructura digital de transformación (disruptiva y, también, de adecuación. Como resultado de todo ello, un “nuevo ENTORNO vital, expandido y complejo”, impacta notablemente en la manera en que nos relacionamos, vivimos, trabajamos y aprendemos. Nos encontramos, pues, ante una nueva clase de situaciones o problemas (complejos que, a la hora de enfrentarnos a los mismos, nos requiere no solo cambiar nuestra forma de pensar y percibir la realidad (pensamiento sistémico, sino también la adopción de una nueva cultura digital, de interdependencia y sostenibilidad. Denominamos como “brecha de la complejidad”, a la dificultad que conlleva la asimilación y práctica de dichos requerimientos y que, a su vez, constituye el principal reto al que nos enfrentamos en la actualidad. Por último, desde una perspectiva de desarrollo orgánico (“bottom- up”, y considerando a la persona como “sistema complejo adaptativo”, se propone el perfil “eAprendiz” como estrategia de adecuación y empoderamiento personal, y profesional, en el actual entorno global, “extendido y complejo”.

  19. Relación entre el consumo de anticonceptivos orales y la endometriosis en pacientes sometidas a laparoscopia. Profamilia, Medellín, 1998-1999

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    Luis Serna

    2001-04-01

    Full Text Available Determinar la relación entre el consumo de anticonceptivos orales y la prevalencia y severidad de la endometriosis en pacientes sometidas a laparoscopia por cualquier causa en Profamilia Medellín, entre julio de 1998 y abril de 1999. El 24.8% del grupo que recibió anticonceptivos tenía endometriosis comparado con el 44.5% del grupo que no los recibió. No hubo asociación entre el consumo de
    anticonceptivos y el grado, tipo o localización de las lesiones. Tampoco se encontró asociación entre tiempo de uso, dosis y tiempo de suspensión de los anticonceptivos con la prevalencia de endometriosis.

  20. Daño por contacto de cerámicas Y-TZP sometidas a degradación hidrotérmica

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    Trinel, Jérémy

    2009-01-01

    Este trabajo evalúa el comportamiento del daño por contacto en cerámicas de circona 3Y-TZP sometida a diferentes tiempos de degradación hidrotérmica (0, 5, 10, 30 y 60 horas), mediante la utilización de metodologías de indentación esférica (hertziana) Se analiza el comportamiento plástico del material mediante la evaluación del daño que se genera producto de la aplicación de cargas monotónicas en la superficie. Así mismo se desarrolla un mapa de daño y se evalúa el comportamie...

  1. Innovación en la reconstrucción del pabellón auricular disgenésico con tejido expandido e implante Innovation in congenital auricular anomaly reconstruction using expanded tissue and prosthetic material

    Directory of Open Access Journals (Sweden)

    P. Iwanyk

    2007-06-01

    Full Text Available En la reconstrucción de un pabellón auricular disgenésico se plantean, básicamente, dos desafíos, reproducir un esqueleto cartilaginoso auricular de forma, tamaño y proyección similar al pabellón auricular normal, y obtener piel suficiente que combine color, textura y grosor semejante a la circundante. Debido a la escasa cantidad de piel útil en esta localización y a la dificultad en el tallado del esqueleto cartilaginoso auricular, iniciamos en 2005 en nuestro Hospital la reconstrucción auricular mediante combinación de tejidos expandidos locales y materiales protésicos, logrando un excelente resultado de apariencia natural.Reconstruction of congenital auricular anomalies includes two essential challenges. The first one is to sculpt an auricular cartilaginous structure that matches the shape, size and projection of a standard ear. The second challenge arises from the scarcity of the usable skin in the area. Because of the difficulty of sculpting a proper cartilage framework and the scarce quantity of skin in the area, in 2005 we began in our hospital auricular reconstruction procedure combining tissue expanders and prosthetic materials achieving a natural appearance and an excellent result.

  2. Cálculo de desplazamientos en placas de vidrio laminado sometidas a carga estática mediante el concepto de módulo de elasticidad efectivo

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    Ismael García García

    2015-03-01

    Full Text Available En los últimos años, el uso de vidrio laminado como elemento estructural se ha incrementado considerablemente en construcciones arquitectónicas, sobre todo en fachadas, cubiertas, escaleras o ventanas de seguridad. El cálculo de estos elementos tipo sándwich no es sencillo debido a la combinación de las propiedades mecánicas del vidrio (elástico-lineales con las del polímero interior (viscoelástico-lineales. Recientemente, algunos autores han propuesto el concepto de espesor efectivo para el cálculo simplificado de elementos de vidrio laminado bajo carga estática, utilizando un modelo monolítico con una rigidez equivalente igual a la del elemento laminado. Debido a la variación de propiedades del laminado con la temperatura, introducidas por el polímero viscoelástico, para cada cambio de temperatura se tiene un espesor efectivo diferente, lo que conlleva un mayor número de evaluaciones para cada una de las situaciones de trabajo del elemento laminado. En este trabajo se propone el concepto de módulo de elasticidad efectivo como una alternativa más eficiente para el cálculo con modelos de elementos finitos. La metodología propuesta se valida mediante ensayos experimentales realizados en placas de vidrio laminado sometidas a una carga uniformemente distribuida.

  3. Vivência de mulheres submetidas à cesiomoldagem Vivencia de mujeres sometidas a radiación de cuello uterino Experiences by women submitted to sealed internal radiotherapy

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    Maria José Clapis

    1996-07-01

    Full Text Available O presente estudo se propôs a identificar as dificuldades e problemas vivenciados pelas pacientes submetidas ao tratamento de cesiomoldagem. Pretendeu ainda oferecer subsídios às enfermeiras para melhor compreensão dessa vivência, quando atuarem como elemento de apoio durante a assistência prestada. Verificou-se que os problemas e dificuldades observados e relatados pelas mulheres estavam relacionados, principalmente, às imposições inerentes ao tratamento, como: isolamento, proibição de visitas, hospitalização, restrição ao leito, restrição de movimentos, uso de sonda vesical de demora e higiene corporal limitada. O medo relacionado à doença, ao tratamento e à anestesia, as orientações parciais ou inexistentes, as lesões na pele, foram queixas que estiveram presentes nas falas da maioria das pacientes deste estudo. O papel da enfermeira torna-se importante no planejamento da assistência de enfermagem em cesiomoldagem, a partir da compreensão dos problemas e dificuldades vivenciados pelas mulheres submetidas a este tratamento.El presente estudio se propone la identificación de las dificultades y problemas vividos por pacientes sometidas al tratamiento de radiación de cuello uterino. Además, pretendió ofrecer conocimientos a las enfermeras, para que puedan identificar mejor las dificultades vividas por las pacientes y actuar como elemento de apoyo en esta asistencia. Las autoras han comprobado que los problemas y dificultades observados y relatados por las mujeres están relacionados, principalmente, con las imposiciones inherentes al tratamiento, como: aislamiento, prohibición de visita, hospitalización, restricción al lecho, restricción de movimientos, uso de sonda vesical de demora e higiene corporal limitada. El miedo relacionado con la enfermedad, el tratamiento y la anestesia, las orientaciones parciales o inexistentes, las lesiones en la piel fueron quejas que estuvieron presentes en las declaraciones de la

  4. Un estudio histórico del problema de las piezas prismáticas rectas sometidas a compresión. Parte I

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    de la Rosa, Emilio

    2007-09-01

    Full Text Available This article presents a historical overview of the key questions that have marked the evolution of the study of straight prismatic elements subjected to compression loads. Straight prismatic elements are researched considering the practical problems on the basis of which models and the theory explaining their behaviour have been developed.The problems that give rise to the origin of the theory of the beam-column are reviewed in the fi rst section (buckling loads and stability and their subsequent developments: imperfections, large deformations, shear deformation and asymmetries. On the other hand, new problems in relationship to the behavior of the material (plasticity, rheology and its three dimensional nature are considered. Finally, the application of fracture and damage theory to the study of the behaviour of the columns is mentioned.En el presente artículo se recogen, desde una perspectiva histórica, las cuestiones básicas que han marcado la evolución del estudio de piezas prismáticas rectas sometidas a compresión. Dicho estudio se lleva a cabo considerando los problemas prácticos en relación con los cuales se han desarrollado tanto los modelos como la teoría que explica su comportamiento.En un primer apartado se recogen los primeros problemas que dan origen al nacimiento de la teoría de la viga-columna (cargas de pandeo y estabilidad y sus posteriores desarrollos: imperfecciones, grandes deformaciones, deformación por cortante y asimetrías. Por otra parte se recogen nuevos problemas en relación con el comportamiento de los materiales (plasticidad, reología y su carácter tridimensional. Por último se menciona la aplicación de la teoría de la fractura y daño al estudio del comportamiento de los pilares.

  5. Análise da absorção de água em dois polímeros expandidos: desenvolvimento do módulo de flutuabilidade de um mini-robô submarino Study of expanded polymers water absorption for buoyancy modulus development of a submarine mini-robot

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    Nadège Bouchonneau

    2010-09-01

    Full Text Available Polímeros expandidos são bastante competitivos para serem utilizados como materiais de flutuabilidade, devido a sua baixa densidade. Em particular, eles se apresentam muito eficientes no desenvolvimento de módulos de flutuabilidade de robôs submarinos do tipo ROV (Remote Operated Vehicle. Este trabalho descreve um estudo da absorção de água em dois diferentes tipos de polímeros expandidos (poliuretano e poliestireno expandido, em diferentes meios aquosos (água do mar e água destilada. Estudo sobre o efeito da geometria das amostras com relação à cinética de absorção de água demonstrou que as amostras com maior área de contato com a água se apresentam mais susceptíveis à absorção de água. Os estudos também revelaram que o poliuretano expandido sofreu uma importante perda de material devido ao seu manuseio durante os ensaios de absorção. A influência do meio aquoso foi também bastante notável para este material, no qual apresentou uma maior taxa de absorção nos ensaios com água destilada em comparação com os ensaios utilizando água do mar. Os resultados das análises demonstraram que o melhor material para ser utilizado como módulo de flutuabilidade do robô submarino é o poliestireno expandido, pois este material não apresentou uma notável degradação e perda de material durante os ensaios de absorção.Owing to the low density and relative low price, expanded polymers appear to be competitive for buoyancy systems. Expanded polymers are particularly efficient to develop buoyancy modules of submarine robots such as ROV (Remote Operated Vehicle. This work describes water absorption mechanisms of two expanded polymers (expanded polyurethane and expanded polystyrene, in various aqueous media (seawater and distilled water. The influence of the samples geometry on the water absorption kinetics was studied. The samples with a larger contact area with water were found to be more susceptible to water absorption

  6. Effect of sugar and water contents on non-expanded cassava flour extrudates Efeitos dos teores de açúcar e água em produtos extrusados não expandidos de farinha de mandioca

    Directory of Open Access Journals (Sweden)

    Juan Antonio Ruano Ortiz

    2010-03-01

    ciclo de gelatinização/retrogradação usando-se um analisador rápido de viscosidade (viscosidade a frio (CV, pico de viscosidade (PV, breakdown e setback. SME e WSI diminuíram em função dos teores de água e açúcar. WAI e as propriedades de pasta foram influenciadas pelo teor de água. Não foi observado o efeito antiplastificante da sacarose nas propriedades de pasta, indicando que a adição de açúcar na mistura de farinha de mandioca não reduziu a capacidade da água em gelatinizar o amido durante o processo de extrusão. A natureza do ponto ótimo para o WAI, PV e BD foi uma sela, enquanto que para SME foi máximo e para CV e SB foi mínimo. Estes resultados podem ser usados na fabricação de produtos extrusados não expandidos de farinha de mandioca contendo açúcar com desejáveis propriedades funcionais para fins específicos.

  7. Utilizacion de tubo laríngeo S® en pacientes sometidas a cirugía laparoscópica ginecológica, Clínica Del Prado, Medellín, Colombia

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    Juliana María Mendoza Villa

    2008-02-01

    Full Text Available

    INTRODUCCIÓN: se ha utilizado con éxito el Tubo Laríngeo Succión (TLS en muchos procedimientos quirúrgicos, incluyendo cirugías con riesgo mayor de broncoaspiración. Con el objetivo de corroborar la eficacia de este dispositivo para prevenir la broncoaspiración diseñamos un estudio descriptivo, observacional y prospectivo utilizando dicho tubo en pacientes sometidas a cirugía laparoscópica ginecológica.

    POBLACIÓN Y METODOLOGÍA: se utilizó el TLS en pacientes ASA I - II sometidas a cirugía ginecológica laparoscópica que cumplieron los criterios de inclusión. Se realizó fibrobroncoscopia por el tubo de drenaje y por el tubo ventilatorio del dispositivo luego de la inducción del neumoperitoneo y al finalizar la cirugía, para determinar la presencia o no de secreción de origen gástrico.

    RESULTADOS: un total de 110 pacientes ingresaron al estudio. No se presentó ningún caso de regurgitación o de broncoaspiración. El éxito en la inserción del dispositivo fue de 94,5% (104 de 110.

    CONCLUSIONES: en el presente estudio encontramos que el

  8. Sentimentos vivenciados por mulheres submetidas a tratamento para Papillomavirus Humano Sentimientos vivenciados por mujeres sometidas a Tratamiento para el Papillomavirus Humano Feelings experienced by women submitted to a treatment for Human Papillomavirus

    Directory of Open Access Journals (Sweden)

    Ana Luiza Santos de Carvalho

    2007-06-01

    Full Text Available A carência de informações sobre o papillomavirus humano pode gerar idéias errôneas sobre o tratamento, o que interfere no contexto sócio-familiar da mulher. Com o objetivo de conhecer os sentimentos vivenciados por mulheres submetidas a tratamento de lesões por papillomavirus humano, foi realizada uma pesquisa qualitativa de natureza exploratória com 12 mulheres, baseada na obtenção e análise de depoimentos por meio de entrevista semi-estruturada. As informações foram analisadas de acordo com a literatura e dispostas em duas temáticas: Reações emocionais e Repercussões no relacionamento. Conclui-se que a mulher que está sendo submetida a tratamento de lesões por papillomavirus humano necessita de cuidados, por parte dos enfermeiros, como forma de melhor enfrentar esse período a qual está vivenciando.La carencia de informaciones sobre el papillomavirus humano puede generar ideas erradas sobre el tratamiento, lo que interfiere en el contexto social y familiar de la mujer. Con el objetivo de conocer los sentimientos vividos por mujeres sometidas a tratamiento de lesiones por papillomavirus humanos, fue realizada una investigación cualitativa de naturaleza exploratoria con 12 mujeres, basada en la obtención y análisis de deposiciones por medio de entrevistas medio-estructurada. Las informaciones fueran analizadas conforme con la literatura y dispuestas en dos temáticas: Reacciones emocionales y Repercusiones en el reracionamiento. Concluyese que la mujer que esta siendo sometida al tratamiento de lesiones por papillomavirus humano necesita de cuidados, por parte de los enfermeros, como forma de mejor enfrentar ese periodo el cual esta viviendo.The lack of information on the papillomavirus human can generate misconception on the treatment interfering in the familiar and social context of the woman. With the purpose to know the feelings experienced by women submitted to treatment of lesions by human papillomavirus, was carried

  9. Un criterio propuesto para distinguir las competencias de control de la Sala Constitucional de la Corte Suprema de Justicia y del Tribunal Supremo de Elecciones en el caso de las normas sometidas a referéndum en Costa Rica

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    Alejandro Robles Leal

    2009-01-01

    Full Text Available El proceso referendario de 2007, previo a la aprobación del Tratado de Libre Comercio entre Centroamérica, significó una gran fiesta cívica para nuestro país, fue la primera vez que, a nivel nacional, el pueblo fue llamado a decidir sobre una propuesta normativa. Sin embargo, entrañó también enormes dudas respecto de las competencias para controlar la constitucionalidad de las normas sometidas a referéndum, y hasta que punto ese control podría acarrear una invasión en el ámbito de competencias por parte de la Sala Constitucional de la Corte Suprema de Justicia al Tribunal Supremo de Elecciones, o viceversa. En este breve trabajo se pretende esbozar un posible criterio para distinguir las competencias de control de ambos órganos, en aras de evitar una invasión, por parte de cualquiera de los dos órganos, en la esfera competencial del otro.

  10. La sexualidad en pacientes con cáncer de mama o cérvix sometidas a tratamiento quirúrgico en el Hospital General, Hospital San Vicente de Paúl e Instituto de Cancerología de la Clínica las Américas, Medellín, 1999

    OpenAIRE

    Fernández S. de S, María Stella; Ospina de González, Bernarda; Múnera Garcés, Adela María

    2002-01-01

    Es necesario tener en cuenta la sexualidad, cuando se va a dar un cuidado de salud integral a la mujer sometida a una mastectomía o histerectomía, a partir del holón erótico y de vinculación afectiva interpersonal, especialmente en la relación de pareja, siendo éste el objeto de esta investigación. Para ella se empleó el método cualitativo de enfoque etnográfico; participaron 27 mujeres, con vida de pareja activa y un año de haber sido sometidas a la cirugía. Se presentó una alteración en el ...

  11. Consenso expandido do BCTRIMS para o tratamento da esclerose múltipla: II. As evidências para o uso de glicocorticóides e imunomoduladores The BCTRIMS expanded consensus on treatment of multiple sclerosis: II. The evidences for the use of glucocorticoids and immunomodulatory treatments

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    Marcos Aurélio Moreira

    2002-09-01

    Full Text Available A esclerose múltipla (EM é doença inflamatória em que mecanismos imunológicos desempenham importante papel na patogênese das lesões do sistema nervoso central. Drogas que agem em diferentes etapas destes mecanismos têm sido usadas em seu tratamento. O presente artigo analisa com base nas classes de evidências científicas e tipos de recomendações propostos pela comunidade científica, os mais importantes ensaios clínico-terapêuticos com os glicocorticóides e os imunomoduladores, incluindo a imunoglobulina humana endovenosa, no tratamento da esclerose múltipla. Ele tem por objetivo fornecer subsídios para a formulação do Consenso Expandido para o Tratamento da Esclerose Múltipla.Multiple sclerosis is an inflammatory disease in which immunological mechanisms play an important role in causing demyelinating lesions in the central nervous system. A number of drugs acting in different stages of these mechanisms have been tested for its treatment. This paper analyses the most important clinical trials with glucocorticoids and immunomodulatory treatments, including human immunoglobulin, using the classes of evidences and types of recommendations as have been defined and widely accepted by the international scientific community. It aims to provide sufficient information to support the BCTRIMS Expanded Consensus on Treatment of MS.

  12. Efecto del almacenamiento al ambiente en semillas de Leucaena leucocephala cv. Cunningham sometidas a hidratación parcial Effect of storage under ambient conditions on seeds from Leucaena leucocephala cv. Cunningham subject to partial hydration

    Directory of Open Access Journals (Sweden)

    Yolanda González

    2012-12-01

    Full Text Available El objetivo del trabajo fue estudiar el efecto del almacenamiento al ambiente en la germinación de las semillas de Leucaena leucocephala cv. Cunningham sometidas a hidratación parcial. Los tratamientos fueron: control, sin escarificación (T0; escarificación térmica (ET con H2O a 80°C, durante dos minutos (T1; ET más hidratación parcial, en bandeja con agua corriente por 28 horas (T2; ET más hidratación parcial, en saco de yute humedecido con agua corriente por 28 horas (T3; ET más hidratación parcial, en bandeja con agua corriente y TMTD al 0,1% (plaguicida por 28 horas (T4; ET más hidratación parcial, en saco de yute humedecido con agua corriente y TMTD al 0,1% (plaguicida por 28 horas (T5. Las semillas hidratadas se deshidrataron durante 72 horas al aire y a la sombra, antes de almacenarlas. Se midió la germinación y la viabilidad a 0, 1, 2, 3, 4, 6, 18, 30 y 42 meses. Se utilizó un diseño totalmente aleatorizado y cuatro réplicas por tratamiento. Hubo diferencias significativas (PThe objective of the work was to study the effect of storage under ambient conditions on the germination of seeds from Leucaena leucocephala cv. Cunningham subject to partial hydration. The treatments were: control, no scarification (T0; thermal scarification (TS with H2O at 80ºC, for two minutes (T1; TS plus partial hydration, on tray with tap water for 28 hours (T2; TS plus partial hydration, in jute sac moist with tap water for 28 hours (T3; TS plus partial hydration in tray with tap water and TMTD at 0,1% (pesticide for 28 hours (T4; TS plus partial hydration, in jute sac moist with tap water and TMTD at 0,1% (pesticide for 28 hours (T5. The hydrated seeds were dehydrated during 72 hours exposed to air and under shade, before being stored. Germination and viability were measured after 0, 1, 2, 3, 4, 6, 18, 30 and 42 months. A completely randomized design and four replications per treatment were used. There were significant differences (P<0

  13. Ambivalência em mulheres submetidas a laqueadura tubária Ambivalencia en mujeres sometidas a ligación de trompas Ambivalence in women submitted to tubal ligation

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    Gleice Adriana Araújo Gonçalves

    2008-12-01

    Full Text Available Pesquisa exploratória, em que se utilizou o banco de dados de pesquisa envolvendo mulheres submetidas a laqueadura tubária, para determinar, mais acuradamente, a freqüência de mulheres ambivalentes e analisar a distribuição estatística dessas mulheres segundo variáveis selecionadas e o modo como haviam se classificado originalmente em relação ao procedimento (totalmente ou moderadamente satisfeitas, ambivalentes, totalmente ou moderadamente arrependidas. O pressuposto do estudo é que, fazendo-se uma avaliação mais precisa das respostas a várias das questões que lhes foram formuladas, o número de mulheres ambivalentes poderia ser superior ao revelado previamente. Esse pressuposto foi confirmado, observando-se um aumento expressivo de mulheres que tanto tinham motivo para satisfação quanto para arrependimento em relação à laqueadura tubária (mulheres ambivalentes. A análise dos resultados permitiu a compreensão de que a ambivalência em relação à laqueadura tubária é um fenômeno que, embora sujeito a múltiplas determinações, envolve uma parcela muito grande da subjetividade da mulher, tornando complexa sua interpretação.Estudio exploratorio, en que se utilizó la base de datos de una investigación con mujeres sometidas a ligadura de trompas, para determinar, con mayor precisión, la frecuencia de mujeres ambivalentes y analizar la distribución estadística de estas mujeres de acuerdo con variables seleccionadas y la forma en que originalmente se habían clasificado en respecto al procedimiento (totalmente o moderadamente satisfecha, ambivalente, moderada o totalmente arrepentida, en un intento de ampliar la comprensión del fenómeno. El presupuesto del estudio era que, haciéndose una evaluación más precisa de las respuestas a varias de las cuestiones que se plantearon, el número de mujeres ambivalente podría ser superior al previamente divulgado. Esta hipótesis se confirmó, señalándose un aumento

  14. Tendências de pesquisas brasileiras sobre mulheres mastectomizadas Tendencias en la investigación sobre la mujer brasileña sometida a mastectomía Trends in research with Brazilian women after mastectomy

    Directory of Open Access Journals (Sweden)

    Elisângela Braga de Azevedo

    2012-12-01

    Full Text Available Objetivou-se analisar as tendências das pesquisas realizadas no Brasil sobre mulheres mastectomizadas. Trata-se de um estudo bibliográfico de abordagem quantitativa, realizado de 15 de junho a 31 de julho de 2009. Para coleta dos dados empíricos utilizou-se um instrumento estruturado, posteriormente os dados foram tabulados, analisados, transformados em porcentagens e agrupados em uma tabela para facilitar a visualização das informações. A amostra foi constituída por resumos adquiridos através de busca eletrónica, utilizando-se as bases de dados da BIREME, LILACS, SciELO, MEDLINE e BDENF. Foram encontrados 111 artigos e após os critérios de inclusão chegou-se à amostra final de 69 artigos. Identificaram-se tendências a pesquisas qualitativas na maioria dos resumos, sendo o maior enfoque dado à reabilitação. A região que mais desenvolveu pesquisas foi a Sudeste, seguida pelo Nordeste. Muitos artigos não apresentavam dados informativos metodológicos essenciais para o entendimento do leitor, dificultando a busca nos referidos bancos de dados.Se ha fijado el objetivo de analizar las tendencias de la investigación realizada en Brasil en mujeres sometidas a mastectomías. Este es un estudio bibliográfico de enfoque cuantitativo, realizado entre el 15 junio y el 31 julio 2009. Para recolectar los datos empíricos, se utilizó un instrumento estructurado, posteriormente los datos fueron tabulados, analizados, transformados en porcentajes y se agrupan en una tabla para facilitar la visualización de la información. La muestra consistió en resúmenes obtenidos mediante una búsqueda electrónica, utilizando las bases de datos de BIREME, LILACS, SciELO, MEDLINE y BDENF. Se encontraron 111 artículos y tras aplicar los criterios de inclusión se llegó a una muestra final de 69 artículos. Se identificó una tendencia hacia la investigación cualitativa en la mayoría de los resúmenes, siendo que el foco principal fue dado a la

  15. Metal-metal-hofteproteser

    DEFF Research Database (Denmark)

    Ulrich, Michael; Overgaard, Søren; Penny, Jeannette

    2014-01-01

    In Denmark 4,456 metal-on-metal (MoM) hip prostheses have been implanted. Evidence demonstrates that some patients develope adverse biological reactions causing failures of MoM hip arthroplasty. Some reactions might be systemic. Failure rates are associated with the type and the design of the Mo...

  16. Influência do substrato e do tamanho da célula de bandejas de poliestireno expandido no desenvolvimento de mudas e produção de calêndula (Calendula officinalis L. Influence of substrate and cell size of expanded polystyrene tray on the development and production of marigold (Calendula officinalis L. seedlings

    Directory of Open Access Journals (Sweden)

    C.K.R Barbosa

    2010-03-01

    Full Text Available A calêndula (Calendula officinalis L. é uma planta medicinal anual de origem Mediterrânica que apresenta propriedades antiinflamatórias, antivirais, antigenotóxicas. A propagação desta planta normalmente é feita por sementes, sendo o uso de bandejas de poliestireno uma forma econômica de produção de mudas. Foram conduzidos dois experimentos com o objetivo de avaliar a interferência de dois tamanhos de célula em bandeja de poliestireno expandido (40 cm³ e 12 cm³ e de dois substratos (solo + esterco bovino curtido e substrato comercial tipo Plantmax para hortaliças® sobre a qualidade de mudas e a produção de calêndula. O delineamento estatístico nos dois experimentos foi em blocos casualizados, dispostos em arranjo fatorial 2 x 2 (dois substratos e dois tamanhos de células com seis repetições. Os tratamentos, referentes aos tamanhos das células foram bandeja com 128 células (40 cm³ de volume e, bandeja com 288 células (12 cm³ de volume. Os substratos utilizados foram solo de cerrado + esterco bovino curtido (1:1 e substrato comercial tipo "Plantmax para hortaliças®". Parte das mudas foi transplantada para avaliação da produção de capítulos. Houve diferenças significativas entre os substratos para as variáveis: matéria seca de parte aérea, matéria seca da raiz e matéria seca total. O uso do substrato formulado com solo de cerrado e esterco bovino proporcionou o melhor desenvolvimento das mudas de calêndula. Contudo, os diferentes tipos de substrato e bandejas de poliestireno não influenciaram significativamente a produção de capítulos das mudas transplantadas.Marigold Calendula (Calendula officinalis L. is an annual medicinal plant of Mediterranean origin which presents anti-inflammatory, antiviral and antigenotoxic properties. This species normally propagates through seeds, and the use of polystyrene trays is an economic way to produce its seedlings. Two experiments were carried out to evaluate the

  17. Estudo comparativo das reações teciduais ao implante de pericárdio bovino e a inclusão de politetrafluoroetileno expandido em ratos A comparison of tissue reactions to bovine pericardial implants and expanded polytetrafluoroethylene inclusions in a rat model

    Directory of Open Access Journals (Sweden)

    Douglas Haddad Filho

    2004-04-01

    Full Text Available OBJETIVO: Comparar a reação tecidual à inclusão de politetrafluoroetileno-expandido com a reação tecidual ao implante de pericárdio bovino. MÉTODOS: Vinte ratos foram divididos em dois grupos iguais: 7 e 30 dias. Um disco de cada material foi introduzido no dorso de cada animal. As peças e o tecido reacional foram retirados 7 e 30 dias após a introdução, para a realização do estudo morfométrico. Para análise estatística foram aplicados os testes de Mann-Whitney e Wilcoxon. RESULTADOS: No PTFE-E, no grupo 30 dias, houve um aumento significante no número de fibroblastos e uma diminuição significante no número de neutrófilos, linfócitos e apilares. Em relação ao pericárdio bovino, ocorreu uma diminuição significante no número de fibroblastos. Quando os mesmos períodos foram comparados, o número de fibroblastos foi significativamente maior no PTFE-E, aos 30 dias, assim como o número de plasmócitos e linfócitos no grupo 30 dias , no pericárdio bovino. CONCLUSÕES: A reposta inflamatória foi menor e menos durável no PTFE-E; a reparação foi menor no PTFE-E e não houve reação de corpo estranho para ambos os materiais.PURPOSE: It is to compare tissue reactions of the expanded polytetrafluoroethyele (E-PTFE implantation and the tissue reaction of the bovine pericardium implants. METHODS: Twenty male rats were divided into two equal groups: 7 and 30 days. A disc-shaped specimen of test material was introduced into each animal's paraspinal region. The material and the tissue were resected 7 and 30 days after the introduction, for morphometric analysis. The Mann-Whitney and Wilcoxon tests were applied for statistical analysis of the results. RESULTS: E-PTFE demonstrated a significant increase in the number of fibroblast at 30 days. A significant drop was noted in the number of neutrophils, lymphocytes and porcentage of capilaries within the time periods. Bovine pericadium displayed a strinking drop in the number of

  18. Metallated metal-organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Bury, Wojciech; Farha, Omar K.; Hupp, Joseph T.; Mondloch, Joseph E.

    2017-08-22

    Porous metal-organic frameworks (MOFs) and metallated porous MOFs are provided. Also provided are methods of metallating porous MOFs using atomic layer deposition and methods of using the metallated MOFs as catalysts and in remediation applications.

  19. Heavy metals

    OpenAIRE

    Adriano, Domy; VANGRONSVELD, Jaco; Bolan, N.S.; Wenzel, W.W.

    2005-01-01

    - Sources of Metals in the Environment - Environmental Contamination - Retention and Dynamics of Metals in Soils - Adsorption - Complexation - Precipitation - Bioavailability–Natural Attenuation Interactions - Biological Response to Metals - Soil Remediation

  20. New metals

    International Nuclear Information System (INIS)

    Bergqvist, U.

    1983-12-01

    The aim of this report is to estimate the exposure to various metals and metal compounds and discuss the available information of the possible toxic effects of these metals and compounds. In the first section, some metals are defined as those with either a large or a fast increasing exposure to living organisms. The available information on toxicity is discussed in the second section. In the third section interesting metals are defined as compounds having a large exposure and an apparent insufficient knowledge of their possible toxic effects. Comments on each of these metals are also to be found in the third section. (G.B.)

  1. Silicone metalization

    Energy Technology Data Exchange (ETDEWEB)

    Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  2. Metallic nanomesh

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Zhifeng; Sun, Tianyi; Guo, Chuanfei

    2018-02-20

    A transparent flexible nanomesh having at least one conductive element and sheet resistance less than 300.OMEGA./.quadrature. when stretched to a strain of 200% in at least one direction. The nanomesh is formed by depositing a sacrificial film, depositing, etching, and oxidizing a first metal layer on the film, etching the sacrificial film, depositing a second metal layer, and removing the first metal layer to form a nanomesh on the substrate.

  3. Plasma metallization

    International Nuclear Information System (INIS)

    Crowther, J.M.

    1997-09-01

    Many methods are currently used for the production of thin metal films. However, all of these have drawbacks associated with them, for example the need for UHV conditions, high temperatures, exotic metal precursors, or the inability to coat complex shaped objects. Reduction of supported metal salts by non-isothermal plasma treatment does not suffer from these drawbacks. In order to produce and analyse metal films before they become contaminated, a plasma chamber which could be attached directly to a UHV chamber with XPS capability was designed and built. This allowed plasma treatment of supported metal salts and surface analysis by XPS to be performed without exposure of the metal film to the atmosphere. Non-equilibrium plasma treatment of Nylon 66 supported gold(lll) chloride using hydrogen as the feed gas resulted in a 95% pure gold film, the remaining 5% of the film being carbon. If argon or helium were used as the feed gases during plasma treatment the resultant gold films were 100% pure. Some degree of surface contamination of the films due to plasma treatment was observed but was easily removed by argon ion cleaning. Hydrogen plasma reduction of glass supported silver(l) nitrate and palladium(ll) acetate films reveals that this metallization technique is applicable to a wide variety of metal salts and supports, and has also shown the ability of plasma reduction to retain the complex 'fern-like' structures seen for spin coated silver(l) nitrate layers. Some metal salts are susceptible to decomposition by X-rays. The reduction of Nylon 66 supported gold(lll) chloride films by soft X-rays to produce nanoscopic gold particles has been studied. The spontaneous reduction of these X-ray irradiated support gold(lll) chloride films on exposure to the atmosphere to produce gold rich metallic films has also been reported. (author)

  4. Estabilidad de ciertas ondas solitarias sometidas a perturbaciones estocasticas

    Science.gov (United States)

    Rodriguez Plaza, Maria Jesus

    The rampant success of quantum theory is the result of applications of the 'new' quantum mechanics of Schrodinger and Heisenberg (1926-7), the Feynman-Schwinger-Tomonaga Quantum Electro-dynamics (1946-51), the electro-weak theory of Salaam, Weinberg, and Glashow (1967-9), and Quantum Chromodynamics (1973-); in fact, this success of 'the' quantum theory has depended on a continuous stream of brilliant and quite disparate mathematical formulations. In this carefully concealed ferment there lie plenty of unresolved difficulties, simply because in churning out fabulously accurate calculational tools there has been no sensible explanation of all that is going on. It is even argued that such an understanding is nothing to do with physics. A long-standing and famous illustration of this is the paradoxical thought-experiment of Einstein, Podolsky and Rosen (1935). Fundamental to all quantum theories, and also their paradoxes, is the location of sub-microscopic objects; or, rather, that the specification of such a location is fraught with mathematical inconsistency. This project encompasses a detailed, critical survey of the tangled history of Position within quantum theories. The first step is to show that, contrary to appearances, canonical quantum mechanics has only a vague notion of locality. After analysing a number of previous attempts at a 'relativistic quantum mechanics', two lines of thought are considered in detail. The first is the work of Wan and students, which is shown to be no real improvement on the iisu.al 'nonrelativistic' theory. The second is based on an idea of Dirac's - using backwards-in-time light-cones as the hypersurface in space-time. There remain considerable difficulties in the way of producing a consistent scheme here. To keep things nicely stirred up, the author then proposes his own approach - an adaptation of Feynman's QED propagators. This new approach is distinguished from Feynman's since the propagator or Green's function is not obtained by Feynman's rule. The type of equation solved is also different: instead of an initial-value problem, a solution that obeys a time-symmetric causality criterion is found for an inhomogeneous partial differential equation with homogeneous boundary conditions. To make the consideration of locality more precise, some results of Fourier transform theory are presented in a form that is directly applicable. Somewhat away from the main thrust of the thesis, there is also an attempt to explain, the manner in which quantum effects disappear as the number of particles increases in such things as experimental realisations of the EPR and de Broglie thought experiments.

  5. Estabilidad de papas crisps sometidas a diferentes condiciones de almacenamiento

    Directory of Open Access Journals (Sweden)

    Wittig, Emma

    2001-08-01

    Full Text Available The progression of deterioration of crisps stored at room temperature (day light and darkness, and in darkness at 40ºC and -23ºC (control was evaluated. The samples were obtained from a leader industry of the chilean market. The potatoes were evaluated until the panel detected significant difference (0.05>p for «strange» odour and flavour. Chemical evaluation was performed on the oil extracted from the potatoes. Sensory evaluation showed significant differences (0.05>p against control at 48, 72 and 9 days of storage at daylight and darkness room temperature, and 40ºC respectively. During the frying process about 80% of terbutilhydroquinone (TBHQ was lost, delta and gamma tocopherol decreased around 43 and 30% respectively. Thermic deterioration was the most important during frying while only oxidation increased during storage. A relationship between sensory and chemical deterioration was established. It was found that, for the same polar compound percentage, a period of time around 7 times higher was necessary at room temperature in darkness, than at 40ºC.Se evaluó la progresión del deterioro de papas crisps almacenadas a temperatura ambiente en presencia de luz y en oscuridad, así como 40ºC y –23ºC (control en oscuridad. Se trabajó con muestras que provinieron de una industria líder en el mercado chileno. El deterioro se evaluó sensorialmente sobre las hojuelas hasta que el panel obtuvo significación para olor y sabor extraño y químicamente en el aceite extraído de las mismas. La evaluación sensorial indicó que se obtuvieron diferencias significativas (0.05>p contra el control a los 48, 72 y 9 días de almacenamiento a T ambiente en presencia de luz, en oscuridad y 40ºC, respectivamente. Durante el proceso de fritura se produjo una pérdida del orden de 80% de terbutilhidroquinona (TBHQ, delta y gama tocoferol disminuyeron entre un 43 y 30% respectivamente. El deterioro predominante fue de tipo térmico, en cambio durante el almacenamiento se observó una evolución hacia el deterioro oxidativo. Se estableció una relación entre el deterioro sensorial y químico, obteniéndose que si un valor de compuestos polares se alcanza en un tiempo determinado a 40ºC, se necesitaría aproximadamente 7 veces ese tiempo, para alcanzarlo a temperatura ambiente en oscuridad.

  6. TEORES SÉRICOS DE CORTISOL DE FÊMEAS CANINAS (Canis familiaris – LINNAEUS, 1758 SUBMETIDAS À CESARIANA SERIC LEVELS OF CORTISOL IN BITCHES (Canis familiaris – LINNAEUS, 1758 SUBMITTED TO AESARIAN SECTION Niveles séricos del cortisol en perras (Canis familiaris – Linnaeus, 1758 sometidas a cesárea

    Directory of Open Access Journals (Sweden)

    Diogo José Cardilli

    2009-12-01

    . The reserved serum was used to realization of cortisol measure by radioimmunoassay (on already described periods. The statistics analyzes were made by t test and Tukey. The cortisol levels presented difference (p< 0.05 in the dog of caesarian section (6.83 µg/dL but this didn’t differ (p> 0.05 on subsequent days (1.82 µg/dL, 24 hours later; 1.38 µg/dL, 48 hour later; 1.48 µg/dL, 10 days later. The middle values of control group were 3.43, 2.01, 3.59 e 1.72 µg/dL, in partum day, 24 hours later, 48 hours later and 10 days later. The stress because partum dystocic induced to liberation of cortisol, normalizing in subsequent days, but don’t have variation after cesarian (surgical stress don’t induced bigger liberation of cortisol or partum natural, composed compatible with the one found in the literature.

KEY WORDS: Bitches, caesarian section, cortisol.
Perras sometidas a cesárea por estar en situación distinta de la fisiológica, pueden presentar alteraciones séricas para se adaptaren a esa nueva condición de estrés. Una de las posibles alteraciones, es la concentración de cortisol durante el período peri-parto. Siendo así, el objetivo de ese estudio fue cuantificar los niveles séricos del cortisol en perras sometidas a cesárea en la fase de parto y posparto en la fase de parto y posparto (en el día del acto quirúrgico o parto, 24h, 48h y 10 días después. El método de radioinmunoensayo fue utilizado para la realización del dosaje de cortisol sérico (en los períodos ya descritos. La evaluación estadística fue realizada por medio de los testes t y Tukey. El nivel de cortisol sérico presentó diferencia (p< 0,05 en el día de la cesárea (6,83 µg/dL, pero no hubo diferencia estadística (p> 0,05 en los días consecutivos (1,82 µg/dL, 24 horas después; 1,38 µg/dL, 48 horas después; 1,48 µg/dL 10 días después. Los niveles medios del grupo control

  • Regurgitación y aspiración de contenido gástrico en pacientes sometidas a cirugía laparoscópica ginecológica con tubo laríngeo con succión

    Directory of Open Access Journals (Sweden)

    Juliana María Mendoza Villa

    2008-11-01

    Full Text Available

    OBJETIVO: determinar la incidencia de regurgitación y aspiración de contenido gástrico en pacientes sometidas a laparoscopia ginecológica (LG electiva bajo anestesia general, con la utilización del Tubo laríngeo con succión.

     

    DISEÑO: estudio clínico prospectivo, observacional y descriptivo.

     

    SITIO: Clínica del Prado, Medellín, Antioquia, Colombia.

     

    INTERVENCIONES: manejo de la vía aérea con Tubo laríngeo- S™ (TL-S™; VBM Medizintechnik, Sulz, Alemania.

     

    Metal cyanides

    International Nuclear Information System (INIS)

    Wells, A.F.

    1988-01-01

    From the biewpoint of general crystal T chemistry principles and on the basis of modern data the structural chemistry of metal cyanites is presented. The features of the structure of the following compounds are considered: simple ionic alkali cyanides (Li-Cs) containing CN - ions; molybdenum (4,5), tungsten (4,5), rhenium (5,6) complexes etc, where-CN group is only connected with one metal atom; covalent cyanides of cadmium and other elements in which the CN-group serves as a bridge

  • Resultados perinatales de las mujeres con ruptura de las membranas ovulares entre las semanas 24 y 34 de la gestación sometidas a manejo expectante en el Hospital Universitario San Vicente de Paúl, Medellín-Colombia

    Directory of Open Access Journals (Sweden)

    Álvaro Antonio Araque Fernández

    2008-11-01

    Full Text Available La literatura mundial sobre el manejo de la ruptura prematura de membranas ovulares pretérmino (RPMOP y sobre los resultados perinatales, informa de una disminución de la morbilidad y la mortalidad de los recién nacidos cuyas madres recibieron profilaxis con antibióticos, pero algunos estudios presentan inconsistencias en su metodología, lo que se demuestra con el análisis del estudio ORACLE, por parte del Centro Latinoamericano de Perinatología y de Desarrollo Humano (CLAP. Esta organización consideró sin validez suficiente la conclusión acerca de la disminución de la morbilidad y mortalidad perinatales con el uso de antibióticos en el cual se hizo un análisis general para dos poblaciones distintas, una con RPMOP y otra con APP (amenaza de parto prematuro; el error metodológico estimado fue no realizar análisis por subgrupos como dos poblaciones diferentes. En el Hospital Universitario San Vicente de Paúl (HUSVP de Medellín, Colombia, se hace un manejo expectante de la RPMOP, el cual no incluye uso de antibióticos. El objetivo de esta investigación fue describir los desenlaces perinatales de las mujeres con RPMOP de acuerdo con los diferentes grupos de edad gestacional y los diferentes períodos de latencia, atendidas en el HUSVP y sometidas al protocolo institucional que consiste en manejo expectante, sin antibióticos. Esta investigación fue descriptiva prospectiva con mujeres cuya edad gestacional estaba comprendida entre las 24 y 33semanas + 6 días con diagnóstico de RPMOP. El diagnóstico se efectuó por el examen clínico y/o la prueba de índigo carmín. El seguimiento consistió en evaluación clínica, monitoreo electrónico fetal, perfil biofísico fetal (PBF y reactantes de fase aguda realizados periódicamente. Se evaluaron los siguientes desenlaces primarios: muerte perinatal, corioamnionitis, síndrome de dificultad respiratoria (SDR, sepsis temprana, hemorragia intraventricular (HIV, enterocolitis necrosante

  • EVALUACIÓN DEL COMPORTAMIENTO DE ARCILLAS SOMETIDAS A DIFERENTES TIEMPOS DE EXPOSICIÓN A ALTAS TEMPERATURAS AVALIAÇÃO DO COMPORTAMENTO DE ARGILAS SUBMETIDAS A DIFERENTES TEMPOS DE EXPOSIÇÃO A ALTAS TEMPERATURAS BEHAVIOR EVALUATION OF CLAYS SUBJECTED TO DIFFERENT EXPOSURES TIMES AT HIGH TEMPERATURES

    Directory of Open Access Journals (Sweden)

    Hugo Alexánder Rondón

    2011-12-01

    Full Text Available El artículo presenta el cambio que experimentan dos arcillas en sus propiedades índice, de expansión y resistencia a la compresión inconfinada cuando se someten a altas temperaturas (150, 225 y 300 °C durante tres tiempos de exposición (1, 7 y 15 días. Además se estudió si las arcillas recuperan las propiedades mencionadas después de ser sometidas a altas temperaturas y de ser nuevamente expuestas a la temperatura ambiente durante una semana en el laboratorio. El objetivo general de la investigación es evaluar si la aplicación de temperatura puede utilizarse como mecanismo de estabilización de arcillas o fabricación de llenante mineral. Los resultados muestran que la plasticidad, el potencial de expansión y la resistencia a la compresión simple de las arcillas ensayadas disminuyen cuando se eleva la temperatura de las muestras entre 150 ºC y 300 ºC y se incrementa el tiempo de exposición. También se encontró que la recuperación de las propiedades de las arcillas es nula cuando se someten a 300 °C durante 15 días.O artigo apresenta a mudança que experimentam duas argilas em suas propriedades índice, de expansão e resistência à compressão não confinada quando se submetem a altas temperaturas (150, 225 e 300 °C durante três tempos de exposição (1,7 e 15 dias. Ademais estudou-se se as argilas recuperam as propriedades mencionadas, após ser submetidas a altas temperaturas e de ser novamente expostas à temperatura ambiente durante uma semana no laboratório. O objetivo geral da pesquisa é avaliar se a aplicação de temperatura pode ser utilizada como mecanismo de estabilização de argilas ou fabricação de filler mineral. Os resultados mostram que a plasticidade, o potencial de expansão e a resistência à compressão simples das argilas ensaiadas diminuem quando se eleva a temperatura das mostras entre 150 ºC e 300 ºC e se incrementa o tempo de exposição. Também se encontrou que a recuperação das

  • Cambios en la estructura, la población y la composición de 19 accesiones de Panicum maximum sometidas a pastoreo CIAT-184 Changes in the structure, population and composition of 19 Panicum maximum accessions under grazing conditions

    Directory of Open Access Journals (Sweden)

    R Machado

    2012-06-01

    Full Text Available Este trabajo tuvo como objetivo caracterizar los cambios y la tendencia de indicadores relacionados con la estructura, la población y la composición en 19 accesiones de Panicum maximum cuando fueron sometidas a condiciones de pastoreo simulado. Las rotaciones se hicieron cada 32-40 días en el periodo lluvioso y 60-70 días en el poco lluvioso, con intensidad de pastoreo de 80-135 UGM/ha/día (los dos primeros años y 120-160 UGM/ha/día (tercer año. Se utilizó un diseño de bloques al azar con tres repeticiones. Aunque en todos los tratamientos disminuyó la relación vástagos vivos/vástagos muertos, este cociente fue superior a uno, por lo que el ritmo de sustitución de vástagos fue favorable. En el 84,2% de los tratamientos se incrementó el número de macollas con relación a el estatus inicial. El porcentaje de arvenses aumentó con las rotaciones, pero ninguno de los tratamientos alcanzó un estado de deterioro avanzado. En este indicador se destacaron los tipos gigantes CIH-13, SIH-697, CIH-3, CC-1146 y SIH-10, con valores que variaron entre 4,6 y 14,1%, así como los tipos medianos CIH-15 y Tardío pequeño, con 10 y 12,3%, respectivamente. Se concluye que el germoplasma evaluado mostró valores adecuados, en función de los indicadores relacionados con la estructura de la macolla, la población y el porcentaje de invasión de las especies arvenses, aunque se identificó un alto contraste entre los tipos gigantes y medianos y dentro de estos grupos. Se sugiere analizar el resto de los indicadores productivos y con ello determinar los tipos más sobresalientes, sobre la base de los resultados en todos los indicadores incluidos.The objective of this work was to characterize the changes and trend of indicators related to the structure, population and composition in 19 Panicum maximum accessions under simulated grazing conditions. The rotations took place every 32-40 days in the rainy season and 60-70 days in the dry season, with

  • heavy metals

    African Journals Online (AJOL)

    NICO

    aDepartment of Chemistry, Tshwane University of Technology, P.O. Box 56208, Arcadia, 0007, South Africa. bSchool of Health Systems and Public Health, Faculty of Health Sciences, ... ing the levels of toxic metals in food.15,19 Compared to ET-AAS or .... mum pressure 350 psi and maximum temperature 210 °C. The.

  • Corrosion of valve metals

    International Nuclear Information System (INIS)

    Draley, J.E.

    1976-01-01

    A general survey related to the corrosion of valve metals or film-forming metals. The way these metals corrode with some general examples is described. Valve metals form relatively perfect oxide films with little breakdown or leakage when anodized

  • Glassy metals

    CERN Document Server

    Russew, Krassimir

    2016-01-01

    The topics discussed in this book focus on fundamental problems concerning the structural relaxation of amorphous metallic alloys, above all the possibility of studying it on the basis of viscous flow behavior and its relation to rheological anomalies, such as bend stress relaxation, thermal expansion, specific heat, density changes, and crystallization. Most relaxation studies deal with the relaxation changes of a single definite material property, and not with a wider spectrum of physical properties integrated into a common framework. This book shows that it is possible to describe these property changes on the basis of a more comprehensive theoretical understanding of their mechanism.

  • Características técnicas y resultados maternos y perinatales de las pacientes isoinmunizadas sometidas a transfusión fetal intrauterina Hospital Universitario San Vicente de Paúl, Medellín, Colombia, 1998-2006

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Rebolledo López

    2008-02-01

    Full Text Available

    OBJETIVO: describir las características sociodemográficas, clínicas y técnicas y los resultados maternos y perinatales de las pacientes isoinmunizadas sometidas a transfusión fetal intrauterina (TFI en el Hospital Universitario San Vicente de Paúl (HUSVP de Medellín, Colombia, entre los años 1998 y 2006.

    METODOLOGÍA: se realizó un estudio descriptivo retrospectivo de 13 pacientes isoinmunizadas que requirieron TFI en el HUSVP entre 1998 y 2006. Se analizaron variables como ruptura prematura de membranas ovulares (RPMO, corioamnionitis, sufrimiento fetal agudo (SFA, muerte perinatal e hidropesía fetal; además se describen las características técnicas de las transfusiones así como las complicaciones relacionadas con el procedimiento.

    RESULTADOS: a un total de 13 madres isoinmunizadas se les hicieron 29 TFI. La tasa de supervivencia fetal fue del 77%. Se complicaron 5 de las madres (38,5% así: RPMO en 3 casos (23% y corioamnionitis en 2 (15,4%. Seis fetos (46,1% presentaron al menos una complicación. Tres fetos fallecieron (23%, 2 (15,4% presentaron hidropesía inmune, y en 4 (30,8% hubo SFA. En total se realizaron 29 transfusiones durante las cuales hubo 11complicaciones en 6 fetos así: bradicardia fetal 4 (13,7%, desgarro del cordón 1 (3,4%, hematomas del cordón 2 (6,8% y sangrado postransfusión 4

  • Extracting metals directly from metal oxides

    International Nuclear Information System (INIS)

    Wai, C.M.; Smart, N.G.; Phelps, C.

    1997-01-01

    A method of extracting metals directly from metal oxides by exposing the oxide to a supercritical fluid solvent containing a chelating agent is described. Preferably, the metal is an actinide or a lanthanide. More preferably, the metal is uranium, thorium or plutonium. The chelating agent forms chelates that are soluble in the supercritical fluid, thereby allowing direct removal of the metal from the metal oxide. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is selected from the group consisting of β-diketones, halogenated β-diketones, phosphinic acids, halogenated phosphinic acids, carboxylic acids, halogenated carboxylic acids, and mixtures thereof. In especially preferred embodiments, at least one of the chelating agents is fluorinated. The method provides an environmentally benign process for removing metals from metal oxides without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the metal recovered, to provide an economic, efficient process. 4 figs

  • Metals production

    Science.gov (United States)

    Beck, Theodore S.

    1992-01-01

    Existing procedures for design of electrochemical plants can be used for design of lunar processes taking into consideration the differences in environmental conditions. These differences include: 1/6 Earth gravity, high vacuum, solar electrical and heat source, space radiation heat sink, long days and nights, and different availability and economics of materials, energy, and labor. Techniques have already been developed for operation of relatively small scale hydrogen-oxygen fuel cell systems used in the U.S. lunar landing program. Design and operation of lunar aqueous electrolytic process plants appears to be within the state-of-the-art. Finding or developing compatible materials for construction and designing of fused-magma metal winning cells will present a real engineering challenge.

  • The Sounds of Metal

    DEFF Research Database (Denmark)

    Grund, Cynthia M.

    2015-01-01

    Two, I propose that this framework allows for at least a theoretical distinction between the way in which extreme metal – e.g. black metal, doom metal, funeral doom metal, death metal – relates to its sound as music and the way in which much other music may be conceived of as being constituted...

  • Web-séries no contexto dos Universos Narrativos Expandidos

    Directory of Open Access Journals (Sweden)

    Thiago Altafini

    2010-10-01

    Full Text Available Este artigo aborda o formato web-série por meio do conceito de narrativa transmídia, e contextualiza esse produto audiovisual no panorama da “cultura da convergência”. Como objeto de análise serão utilizadas as produções The Cell, da Fox Int ernational e Flying Kebab, produção nacional independente.

  • Perniola, Mario: La estética contemporánea y El arte expandido.

    Directory of Open Access Journals (Sweden)

    Óscar Ortega Ruiz

    2016-01-01

    Full Text Available Recientemente, han llegado a las librerías dos nuevas publicaciones de una de las grandes personalidades del pensamiento filosófico italiano, el profesor Mario Perniola, catedrático de Estética de la Universidad Tor Vergata de Roma. Este veterano intelectual de origen piamontés, nacido en 1941, ha ddedicado la mayor parte de su carrera a la reflexión acerca de los problemas y retos surgidos en el seno de la disciplina estética de los últimos decenios, tales como la evolución de las vanguardias, el situacionismo –movimiento en el que estuvo directamente involucrado–, los estudios culturales, el postmodernismo, el posthumanismo, etc.

    1. Efeitos da associação entre pequenas doses subaracnóideas de morfina e cetoprofeno venoso e oral em pacientes submetidas à cesariana Efectos de la asociación entre pequeñas dosis subaracnóideas de morfina y cetoprofeno venoso y oral en pacientes sometidas a cesariana Effects of low spinal morphine doses associated to intravenous and oral ketoprofen in patients submitted to cesarean sections

      Directory of Open Access Journals (Sweden)

      Eliana Marisa Ganem

      2003-08-01

      Full Text Available JUSTIFICATIVA E OBJETIVOS: Pequenas doses subaracnóideas de morfina são eficazes em reduzir a dor pós-operatória de pacientes submetidas à cesariana, com menor incidência de efeitos colaterais. O objetivo desta pesquisa foi avaliar a qualidade da analgesia pós-operatória e a ocorrência de efeitos colaterais em pacientes submetidas a cesarianas, sob anestesia subaracnóidea com bupivacaína hiperbárica e morfina nas doses de 0,05 mg e 0,1 mg, associadas ao cetoprofeno pelas vias venosa e oral. MÉTODO: Participaram do estudo 60 gestantes de termo, estado físico ASA I e II, que foram submetidas à cesariana eletiva. As pacientes foram divididas em dois grupos: grupo 1 - morfina 0,1 mg, grupo 2 - 0,05 mg, associada a 15 mg de bupivacaína hiperbárica. Todas receberam cetoprofeno (100 mg por via venosa no per-operatório e por via oral a cada 8 horas no primeiro dia de pós-operatório. As pacientes foram avaliadas 6, 12 e 24 horas após o término da cirurgia, com relação à intensidade da dor e presença de efeitos colaterais (sedação, prurido, náusea e vômito. A presença destes últimos também foi avaliada no per-operatório. RESULTADOS: Ambos os grupos foram idênticos quanto aos dados antropométricos e à duração da cirurgia e da anestesia. Também foram homogêneos com relação à intensidade da dor pós-operatória e à presença de prurido, sedação, náusea e vômito. CONCLUSÕES: A morfina, nas doses de 0,05 mg e 0,1 mg administradas no espaço subaracnóideo, associada ao cetoprofeno pelas vias venosa e oral, apresentou a mesma qualidade de analgesia pós-operatória e determinou a mesma ocorrência de efeitos colaterais.JUSTIFICATIVA Y OBJETIVOS: Pequeñas dosis subaracnóideas de morfina son eficaces en reducir el dolor pos-operatorio de pacientes sometidas a cesariana, con menor incidencia de efectos colaterales. El objetivo de esta pesquisa fue evaluar la calidad de la analgesia pos-operatoria y la ocurrencia

    2. Heavy metal jako subkultura

      OpenAIRE

      KOUTNÁ, Daniela

      2016-01-01

      This bachelor thesis deals with heavy metal subculture. Its aim is to introduce the most important branches and to show broadness of heavy metal. This bachelor thesis describes development and history, briefly shows Czech heavy metal history alongside with the biggest and most popular Czech heavy metal festivals. It shows the most dressing concerns of society against this style.

    3. METAL PRODUCTION AND CASTING

      Science.gov (United States)

      Magel, T.T.

      1958-03-01

      This patent covers a method and apparatus for collecting the molten metal produced by high temperature metal salt reduction. It consists essentially of subjecting the reaction vessel to centrifugal force in order to force the liberatcd molten metal into a coherent molten mass, and allowing it to solidify there. The apparatus is particularly suitable for use with small quantities of rare metals.

    4. Amorphous metal composites

      International Nuclear Information System (INIS)

      Byrne, M.A.; Lupinski, J.H.

      1984-01-01

      This patent discloses an improved amorphous metal composite and process of making the composite. The amorphous metal composite comprises amorphous metal (e.g. iron) and a low molecular weight thermosetting polymer binder. The process comprises placing an amorphous metal in particulate form and a thermosetting polymer binder powder into a container, mixing these materials, and applying heat and pressure to convert the mixture into an amorphous metal composite

    5. Alkali metals and group IIA metals

      International Nuclear Information System (INIS)

      Fenton, D.E.

      1987-01-01

      This chapter on the coordination complexes of the alkali metals of group IIA starts with a historical perspective of their chemistry, from simple monodentate ligands, metal-β-diketonates to the macrocyclic polyethers which act as ligands to the alkali and akaline earth metals. Other macrocyclic ligands include quarterenes, calixarenes, porphyrins, phthalocyanines and chlorophylls. A section on the naturally occurring ionophores and carboxylic ionophores is included. (UK)

    6. Predicting dietborne metal toxicity from metal influxes

      Science.gov (United States)

      Croteau, M.-N.; Luoma, S.N.

      2009-01-01

      Dietborne metal uptake prevails for many species in nature. However, the links between dietary metal exposure and toxicity are not well understood. Sources of uncertainty include the lack of suitable tracers to quantify exposure for metals such as copper, the difficulty to assess dietary processes such as food ingestion rate, and the complexity to link metal bioaccumulation and effects. We characterized dietborne copper, nickel, and cadmium influxes in a freshwater gastropod exposed to diatoms labeled with enriched stable metal isotopes. Metal influxes in Lymnaea stagnalis correlated linearly with dietborne metal concentrations over a range encompassing most environmental exposures. Dietary Cd and Ni uptake rate constants (kuf) were, respectively, 3.3 and 2.3 times higher than that for Cu. Detoxification rate constants (k detox) were similar among metals and appeared 100 times higher than efflux rate constants (ke). Extremely high Cu concentrations reduced feeding rates, causing the relationship between exposure and influx to deviate from linearity; i.e., Cu uptake rates leveled off between 1500 and 1800 nmol g-1 day-1. L. stagnalis rapidly takes up Cu, Cd, and Ni from food but detoxifies the accumulated metals, instead of reducing uptake or intensifying excretion. Above a threshold uptake rate, however, the detoxification capabilities of L. stagnalis are overwhelmed.

    7. Recycling of Metals

      DEFF Research Database (Denmark)

      Damgaard, Anders; Christensen, Thomas Højlund

      2011-01-01

      Metals like iron and aluminium are produced from mineral ore and used for a range of products, some of which have very short lifetimes and thus constitute a major fraction of municipal waste. Packaging in terms of cans, foils and containers are products with a short lifetime. Other products like...... appliances, vehicles and buildings, containing iron and aluminium metals, have long lifetimes before they end up in the waste stream. The recycling of production waste and postconsumer metals has a long history in the metal industry. Some metal smelters are today entirely based on scarp metals. This chapter...... describes briefly how iron and aluminium are produced and how scrap metal is recycled in the industry. Quality requirements and use of recycled products are discussed, as are the resource and environmental issues of metal recycling. Copper and other metals are also found in waste but in much smaller...

    8. Metal-on-metal hip joint tribology.

      Science.gov (United States)

      Dowson, D; Jin, Z M

      2006-02-01

      The basic tribological features of metal-on-metal total hip replacements have been reviewed to facilitate an understanding of the engineering science underpinning the renaissance of these hard-on-hard joints. Metal-on-polymer hip replacements operate in the boundary lubrication regime, thus leading to the design guidance to reduce the femoral head diameter as much as is feasible to minimize frictional torque and volumetric wear. This explains why the gold-standard implant of this form from the past half-century had a diameter of only 22.225 mm (7/8 in). Metal-on-metal implants can operate in the mild mixed lubrication regime in which much of the applied load is supported by elastohydrodynamic films. Correct tribological design leads to remarkably low steady state wear rates. Promotion of the most effective elastohydrodynamic films calls for the largest possible head diameters and the smallest clearances that can reasonably be adopted, consistent with fine surface finishes, good sphericity and minimal structural elastic deformation of the cup on its foundations. This guidance, which is opposite in form to that developed for metal-on-polymer joints, is equally valid for solid (monolithic) metallic heads on metallic femoral stems and surface replacement femoral shells. Laboratory measurements of friction and wear in metal-on-metal joints have confirmed their potential to achieve a very mild form of mixed lubrication. The key lies in the generation of effective elastohydrodynamic lubricating films of adequate thickness compared with the composite roughness of the head and cup. The calculation of the film thickness is by no means easy, but the full procedure is outlined and the use of an empirical formula that displays good agreement with calculations based upon the full numerical solutions is explained. The representation of the lambda ratio, lambda, embracing both film thickness and composite roughness, is described.

    9. Nanochemistry of metals

      International Nuclear Information System (INIS)

      Sergeev, Gleb B

      2001-01-01

      The results of studies on the nanochemistry of metals published in recent years are generalised. Primary attention is centred on the methods for the synthesis of nanoparticles and their chemical reactions. The means of stabilisation of nanoparticles which involve individual metals and incorporate atoms of several metals are considered as well as their physicochemical properties. Self-assembling processes of nanoparticles are described. The prospects of using metal nanoparticles in semiconductor devices, catalysis, biology and medicine are discussed. The bibliography includes 165 references.

    10. Marks of Metal Copenhell

      DEFF Research Database (Denmark)

      2015-01-01

      Planchebaseret udendørs udstilling på musikfestivalen Copenhell 18-20/6 2015. En mindre udgave af udstillingen Marks of Metal - Logodesign og visualitet i heavy metal. Udarbejdet i samarbejde med Mediemuseet.......Planchebaseret udendørs udstilling på musikfestivalen Copenhell 18-20/6 2015. En mindre udgave af udstillingen Marks of Metal - Logodesign og visualitet i heavy metal. Udarbejdet i samarbejde med Mediemuseet....

    11. Cryochemistry of Metal Nanoparticles

      International Nuclear Information System (INIS)

      Sergeev, Gleb B.

      2003-01-01

      The interaction of metal atoms, clusters and nanoparticles with different organic and inorganic substances were studied at low temperature (10-40K). Combination of matrix isolation technique and preparative cryochemistry was applied for the investigation of activity and selectivity of metal particles of different size. Encapsulation of metal nanoparticles in polymers was studied. The metal-polymer films thus obtained exhibited satisfactory sensitivity to ammonia

    12. Cryochemistry of Metal Nanoparticles

      Energy Technology Data Exchange (ETDEWEB)

      Sergeev, Gleb B. [Moscow State University, Laboratory of Low Temperature Chemistry, Chemistry Department (Russian Federation)], E-mail: gbs@kinet.chem.msu.ru

      2003-12-15

      The interaction of metal atoms, clusters and nanoparticles with different organic and inorganic substances were studied at low temperature (10-40K). Combination of matrix isolation technique and preparative cryochemistry was applied for the investigation of activity and selectivity of metal particles of different size. Encapsulation of metal nanoparticles in polymers was studied. The metal-polymer films thus obtained exhibited satisfactory sensitivity to ammonia.

    13. Cryochemistry of Metal Nanoparticles

      Science.gov (United States)

      Sergeev, Gleb B.

      2003-12-01

      The interaction of metal atoms, clusters and nanoparticles with different organic and inorganic substances were studied at low temperature (10-40K). Combination of matrix isolation technique and preparative cryochemistry was applied for the investigation of activity and selectivity of metal particles of different size. Encapsulation of metal nanoparticles in polymers was studied. The metal-polymer films thus obtained exhibited satisfactory sensitivity to ammonia.

    14. Fungitoxicity of metal ions

      Energy Technology Data Exchange (ETDEWEB)

      Somers, E

      1961-01-01

      The in vitro fungistatic activity of some twenty-four metal cations has been determine against Alternaria tenuis and Botrytis fabae. The metal salts, mainly nitrates, were tested in aqueous solution without added spore germination stimulant. The logarithm of the metal ion concentration at the ED 50 value has been found to conform to the exponenttial relationship with electronegativity proposed by Danielli and Davies (1951). These results are discussed in relation to the site of action of metal cations on the fungal cell.

    15. Metallic DFB lasers

      NARCIS (Netherlands)

      Marell, M.J.H.; Nötzel, R.; Smit, M.K.; Hill, M.T.; Pozo, J.; Mortensen, M.; Urbach, P.; Leijtens, X.; Yousefi, M.

      2010-01-01

      In this paper we present our latest results on the design, fabrication and characterization of metal coated DFB lasers. These devices are based on a specialform of the metal-insulator-metal waveguides, which support plasmon gap modes. The distributed feedback provides control over the laser ~

    16. The metal borohydrides

      International Nuclear Information System (INIS)

      Mirsaidov, U.M.

      2004-01-01

      Publications on borohydrides of metals are systematized in the monograph. Special attention is paid to investigation in the field of synthesis and properties of borohydrides of rare-earth metals, which were carried out under author's supervision. The monograph reviews the basic types of chemical reactions, which are inherent to borohydrides of metals, and structural principles account for their molecular and crystal structures

    17. Intoxication with metallic mercury

      International Nuclear Information System (INIS)

      Fichte, B.; Assmann, H.; Ritzau, F.

      1984-01-01

      Intoxications by metallic mercury are extremely rare. Report of a patient, who tried to commit suicide by subcutaneous injection of 500 g of metallic mercury. He died 16 months later in the course of the intoxication. A short review is given of effects and reactions of metallic mercury in the human organism. (orig.) [de

    18. Intoxication with metallic mercury

      Energy Technology Data Exchange (ETDEWEB)

      Fichte, B.; Ritzau, F.; Assmann, H.

      1984-02-01

      Intoxications by metallic mercury are extremely rare. Report is given of a patient who tried to commit suicide by subcutaneous injection of 500 g of metallic mercury. He died 16 months later in the course of the intoxication. A short review is given of effects and reactions of metallic mercury in the human organism.

    19. Intoxication with metallic mercury

      Energy Technology Data Exchange (ETDEWEB)

      Fichte, B.; Assmann, H.; Ritzau, F.

      1984-02-01

      Intoxications by metallic mercury are extremely rare. Report is given of a patient, who tried to commit suicide by subcutaneous injection of 500 g of metallic mercury. He died 16 months later in the course of the intoxication. A short review is given of effects and reactions of metallic mercury in the human organism.

    20. Liquid metal cold trap

      International Nuclear Information System (INIS)

      Hundal, R.

      1976-01-01

      A cold trap assembly for removing impurities from a liquid metal is described. A hole between the incoming impure liquid metal and purified outgoing liquid metal acts as a continuous bleed means and thus prevents the accumulation of cover gases within the cold trap assembly

    1. Conducting metal oxide and metal nitride nanoparticles

      Science.gov (United States)

      DiSalvo, Jr., Francis J.; Subban, Chinmayee V.

      2017-12-26

      Conducting metal oxide and nitride nanoparticles that can be used in fuel cell applications. The metal oxide nanoparticles are comprised of for example, titanium, niobium, tantalum, tungsten and combinations thereof. The metal nitride nanoparticles are comprised of, for example, titanium, niobium, tantalum, tungsten, zirconium, and combinations thereof. The nanoparticles can be sintered to provide conducting porous agglomerates of the nanoparticles which can be used as a catalyst support in fuel cell applications. Further, platinum nanoparticles, for example, can be deposited on the agglomerates to provide a material that can be used as both an anode and a cathode catalyst support in a fuel cell.

    2. Metal Nitrides for Plasmonic Applications

      DEFF Research Database (Denmark)

      Naik, Gururaj V.; Schroeder, Jeremy; Guler, Urcan

      2012-01-01

      Metal nitrides as alternatives to metals such as gold could offer many advantages when used as plasmonic material. We show that transition metal nitrides can replace metals providing equally good optical performance for many plasmonic applications.......Metal nitrides as alternatives to metals such as gold could offer many advantages when used as plasmonic material. We show that transition metal nitrides can replace metals providing equally good optical performance for many plasmonic applications....

    3. Semi-metallic polymers

      DEFF Research Database (Denmark)

      Bubnova, Olga; Khan, Zia Ullah; Wang, Hui

      2014-01-01

      Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties; here we report...... that polymers can also be semi-metallic. Semi-metals, exemplified by bismuth, graphite and telluride alloys, have no energy bandgap and a very low density of states at the Fermi level. Furthermore, they typically have a higher Seebeck coefficient and lower thermal conductivities compared with metals, thus being...... a Fermi glass to a semi-metal. The high Seebeck value, the metallic conductivity at room temperature and the absence of unpaired electron spins makes polymer semi-metals attractive for thermoelectrics and spintronics....

    4. Extraction process for removing metallic impurities from alkalide metals

      Science.gov (United States)

      Royer, Lamar T.

      1988-01-01

      A development is described for removing metallic impurities from alkali metals by employing an extraction process wherein the metallic impurities are extracted from a molten alkali metal into molten lithium metal due to the immiscibility of the alkali metals in lithium and the miscibility of the metallic contaminants or impurities in the lithium. The purified alkali metal may be readily separated from the contaminant-containing lithium metal by simple decanting due to the differences in densities and melting temperatures of the alkali metals as compared to lithium.

    5. Metal Matrix Composite Solar Cell Metallization

      Directory of Open Access Journals (Sweden)

      Wilt David M.

      2017-01-01

      Full Text Available Advanced solar cells are moving to ever thinner formats in order to save mass and in some cases improve performance. As cells are thinned, the possibility that they may fracture or cleave due to mechanical stresses is increased. Fractures of the cell can degrade the overall device performance if the fracture propagates through the contact metallization, which frequently occurs. To address this problem, a novel semiconductor metallization system based on multi-walled carbon nanotube (CNT reinforcement, termed metal matrix composite (MMC metallization is under investigation. Electro-mechanical characterization of MMC films demonstrate their ability to provide electrical conductivity over >40 micron wide cracks in the underlying semiconductor, with the carbon nanotubes bridging the gap. In addition, these materials show a “self-healing” behaviour, electrically reconnecting at ~30 microns when strained past failure. Triple junction (TJ space cells with MMC metallization demonstrated no loss in Jsc after intentional fracture, whereas TJ cells with conventional metallization suffer up to 50% Jsc loss.

    6. Metal Borohydrides synthesized from metal borides and metal hydrides

      DEFF Research Database (Denmark)

      Sommer, Sanna

      2014-01-01

      Aarhus C, Denmark email: gallafogh@hotmail.com / sanna-sommer@hotmail.com Magnesium boride, MgB2, ball milled with MH (M = Li, Na, Ca) followed by hydrogenation under high hydrogen pressure, readily forms the corresponding metal borohydrides, M(BH4)x (M = Li, Na, Ca) and MgH2 according to reaction scheme...

    7. Light metal production

      Science.gov (United States)

      Fan, Qinbai

      2016-04-19

      An electrochemical process for the production of light metals, particularly aluminum. Such a process involves contacting a light metal source material with an inorganic acid to form a solution containing the light metal ions in high concentration. The solution is fed to an electrochemical reactor assembly having an anode side containing an anode and a cathode side containing a cathode, with anode side and the cathode side separated by a bipolar membrane, with the solution being fed to the anode side. Light metal ions are electrochemically transferred through the bipolar membrane to the cathode side. The process further involves reducing the light metal ions to light metal powder. An associated processing system is also provided.

    8. Liquid metal steam generator

      International Nuclear Information System (INIS)

      Wolowodiuk, W.

      1975-01-01

      A liquid metal heated steam generator is described which in the event of a tube failure quickly exhausts out of the steam generator the products of the reaction between the water and the liquid metal. The steam is generated in a plurality of bayonet tubes which are heated by liquid metal flowing over them between an inner cylinder and an outer cylinder. The inner cylinder extends above the level of liquid metal but below the main tube sheet. A central pipe extends down into the inner cylinder with a centrifugal separator between it and the inner cylinder at its lower end and an involute deflector plate above the separator so that the products of a reaction between the liquid metal and the water will be deflected downwardly by the deflector plate and through the separator so that the liquid metal will flow outwardly and away from the central pipe through which the steam and gaseous reaction products are exhausted. (U.S.)

    9. Mesostructured metal germanium sulfides

      Energy Technology Data Exchange (ETDEWEB)

      MacLachlan, M.J.; Coombs, N.; Bedard, R.L.; White, S.; Thompson, L.K.; Ozin, G.A.

      1999-12-29

      A new class of mesostructured metal germanium sulfide materials has been prepared and characterized. The synthesis, via supramolecular assembly of well-defined germanium sulfide anionic cluster precursors and transition-metal cations in formamide, represents a new strategy for the formation of this class of solids. A variety of techniques were employed to examine the structure and composition of the materials. Structurally, the material is best described as a periodic mesostructured metal sulfide-based coordination framework akin to periodic hexagonal mesoporous silica, MCM-41. At the molecular scale, the materials strongly resemble microstructured metal germanium sulfides, in which the structure of the [Ge{sub 4}S{sub 10}]{sup 4{minus}} cluster building-blocks are intact and linked via {mu}-S-M-S bonds. Evidence for a metal-metal bond in mesostructured Cu/Ge{sub 4}S{sub 10} is also provided.

    10. Soil heavy metals

      Energy Technology Data Exchange (ETDEWEB)

      Sherameti, Irena [Jena Univ. (Germany). Inst. fuer Allgemeine Botanik und Pflanzenphysiologie; Varma, Ajit (eds.) [Amity Univ., Uttar Pradesh (India). Amity Inst. of Microbial Technology; Amity Science, Technology and Innovation Foundation, Noida, UP (India)

      2010-07-01

      Human activities have dramatically changed the composition and organisation of soils. Industrial and urban wastes, agricultural application and also mining activities resulted in an increased concentration of heavy metals in soils. How plants and soil microorganisms cope with this situation and the sophisticated techniques developed for survival in contaminated soils is discussed in this volume. The topics presented include: the general role of heavy metals in biological soil systems; the relation of inorganic and organic pollutions; heavy metal, salt tolerance and combined effects with salinity; effects on abuscular mycorrhizal and on saprophytic soil fungi; heavy metal resistance by streptomycetes; trace element determination of environmental samples; the use of microbiological communities as indicators; phytostabilization of lead polluted sites by native plants; effects of soil earthworms on removal of heavy metals and the remediation of heavy metal contaminated tropical land. (orig.)

    11. Metal atom oxidation laser

      International Nuclear Information System (INIS)

      Jensen, R.J.; Rice, W.W.; Beattie, W.H.

      1975-01-01

      A chemical laser which operates by formation of metal or carbon atoms and reaction of such atoms with a gaseous oxidizer in an optical resonant cavity is described. The lasing species are diatomic or polyatomic in nature and are readily produced by exchange or other abstraction reactions between the metal or carbon atoms and the oxidizer. The lasing molecules may be metal or carbon monohalides or monoxides

    12. Alkali metal hydride formation

      International Nuclear Information System (INIS)

      1976-01-01

      The present invention relates to a method of producing alkali metal hydrides by absorbing hydrogen gas under pressure into a mixture of lower alkyl mono amines and alkali metal alkyl amides selected from sodium and potassium amides formed from said amines. The present invention also includes purification of a mixture of the amines and amides which contain impurities, such as is used as a catalytic exchange liquid in the enrichment of deuterium, involving the formation of the alkali metal hydride

    13. Tritium in metals

      International Nuclear Information System (INIS)

      Schober, T.

      1990-01-01

      In this Chapter a review is given of some of the important features of metal tritides as opposed to hydrides and deuterides. After an introduction to the topics of tritium and tritium in metals information will be presented on a variety of metal-tritium systems. Of main interest here are the differences from the classic hydrogen behavior; the so called isotope effect. A second important topic is that of aging effects produced by the accumulation of 3 He in the samples. (orig.)

    14. Ion implantation in metals

      International Nuclear Information System (INIS)

      Vook, F.L.

      1977-02-01

      The application of ion beams to metals is rapidly emerging as a promising area of research and technology. This report briefly describes some of the recent advances in the modification and study of the basic properties of metals by ion implantation techniques. Most of the research discussed illustrates some of the new and exciting applications of ion beams to metals which are under active investigation at Sandia Laboratories, Albuquerque

    15. Liquid Metal Transformers

      OpenAIRE

      Sheng, Lei; Zhang, Jie; Liu, Jing

      2014-01-01

      The room temperature liquid metal is quickly emerging as an important functional material in a variety of areas like chip cooling, 3D printing or printed electronics etc. With diverse capabilities in electrical, thermal and flowing behaviors, such fluid owns many intriguing properties that had never been anticipated before. Here, we show a group of unconventional phenomena occurring on the liquid metal objects. Through applying electrical field on the liquid metals immersed in water, a series...

    16. Economics of Metal Markets

      OpenAIRE

      Tilton, J.E.

      1984-01-01

      Simple economic principles can provide useful insights into the behavior of metal markets. In applying these principles, however, the analyst must take into account technology, market structure, government policies, and other institutional factors influencing the nature of metal supply and demand. Knowledge of both economics and the metal markets is essential. One without the other is likely to lead to sterile or even misleading results. In support of the above conclusion, this study exa...

    17. Hydrogen-metal systems

      International Nuclear Information System (INIS)

      Wenzl, H.; Springer, T.

      1976-01-01

      A survey is given on the alloys of metal crystals with hydrogen. The system niobium-hydrogen and its properties are especially dealt with: diffusion and heat of solution of hydrogen in the host crystal, phase diagram, coherent and incoherent phase separation, application of metal-hydrogen systems in technology. Furthermore, examples from research work in IFF (Institut fuer Festkoerperforschung) of the Nuclear Research Plant, Juelich, in the field of metal-H systems are given in summary form. (GSC) [de

    18. Honeycomb metal panel

      International Nuclear Information System (INIS)

      1979-01-01

      Product constituted by a honeycomb metal panel that can be employed to advantage for manufacturing lagging by sandwiching it between two plane sheets, utilized in particular in the nuclear industry where lagging has to have a very long life strength. The honeycomb metal panel is made of an expanded metal extrusion previously cut so as to form, after additional drawing, a honeycomb structure with square or rectangular cells with a plane surface [fr

    19. Metal interactions with boron clusters

      International Nuclear Information System (INIS)

      Grimes, R.N.

      1982-01-01

      This book presents information on the following topics: the structural and bonding features of metallaboranes and metallacarboranes; transition-metal derivatives of nido-boranes and some related species; interactions of metal groups with the octahydrotriborate (1-) anion, B 3 H 8 ; metallaboron cage compounds of the main group metals; closo-carborane-metal complexes containing metal-carbon and metal-boron omega-bonds; electrochemistry of metallaboron cage compounds; and boron clusters with transition metal-hydrogen bonds

    20. Method of producing homogeneous mixed metal oxides and metal--metal oxide mixtures

      International Nuclear Information System (INIS)

      Quinby, T.C.

      1978-01-01

      Metal powders, metal oxide powders, and mixtures thereof of controlled particle size are provided by reacting an aqueous solution containing dissolved metal values with excess urea. Upon heating, urea reacts with water from the solution to leave a molten urea solution containing the metal values. The molten urea solution is heated to above about 180 0 C, whereupon metal values precipitate homogeneously as a powder. The powder is reduced to metal or calcined to form oxide particles. One or more metal oxides in a mixture can be selectively reduced to produce metal particles or a mixture of metal and metal oxide particles

    1. Application of liquid metals for the extraction of solid metals

      International Nuclear Information System (INIS)

      Borgstedt, H.U.

      1996-01-01

      Liquid metals dissolve several solid metals in considerable amounts at moderate temperatures. The dissolution processes may be based upon simple physical solubility, formation of intermetallic phases. Even chemical reactions are often observed in which non-metallic elements might be involved. Thus, the capacity to dissolve metals and chemical properties of the liquid metals play a role in these processes. Besides the solubility also chemical properties and thermochemical data are of importance. The dissolution of metals in liquid metals can be applied to separate the solutes from other metals or non-metallic phases. Relatively noble metals can be chemically reduced by the liquid phases. Such solution processes can be applied in the extractive metallurgy, for instance to extract metals from metallic waste. The recycling of metals is of high economical and ecological importance. Examples of possible processes are discussed. (author)

    2. Conducting metal dithiolate complexes

      DEFF Research Database (Denmark)

      Underhill, A. E.; Ahmad, M. M.; Turner, D. J.

      1985-01-01

      Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound......Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound...

    3. Physics of amorphous metals

      CERN Document Server

      Kovalenko, Nikolai P; Krey, Uwe

      2008-01-01

      The discovery of bulk metallic glasses has led to a large increase in the industrial importance of amorphous metals, and this is expected to continue. This book is the first to describe the theoretical physics of amorphous metals, including the important theoretical development of the last 20 years.The renowned authors stress the universal aspects in their description of the phonon or magnon low-energy excitations in the amorphous metals, e.g. concerning the remarkable consequences of the properties of these excitations for the thermodynamics at low and intermediate temperatures. Tunneling

    4. Purification of uranium metal

      International Nuclear Information System (INIS)

      Suzuki, Kenji; Shikama, Tatsuo; Ochiai, Akira.

      1993-01-01

      We developed the system for purifying uranium metal and its metallic compounds and for growing highly pure uranium compounds to study their intrinsic physical properties. Uranium metal was zone refined under low contamination conditions as far as possible. The degree of the purity of uranium metal was examined by the conventional electrical resistivity measurement and by the chemical analysis using the inductive coupled plasma emission spectrometry (ICP). The results show that some metallic impurities evaporated by the r.f. heating and other usual metallic impurities moved to the end of a rod with a molten zone. Therefore, we conclude that the zone refining technique is much effective to the removal of metallic impurities and we obtained high purified uranium metal of 99.99% up with regarding to metallic impurities. The maximum residual resistivity ratio, the r.r.r., so far obtained was about 17-20. Using the purified uranium, we are attempting to grow a highly pure uranium-titanium single crystals. (author)

    5. Metal borohydrides and derivatives

      DEFF Research Database (Denmark)

      Paskevicius, Mark; Haarh Jepsen, Lars; Schouwink, Pascal

      2017-01-01

      major classes of metal borohydride derivatives have also been discovered: anion-substituted compounds where the complex borohydride anion, BH4 -, is replaced by another anion, i.e. a halide or amide ion; and metal borohydrides modified with neutral molecules, such as NH3, NH3BH3, N2H4, etc. Here, we...

    6. Explosion metal welding

      International Nuclear Information System (INIS)

      Popoff, A.A.

      1976-01-01

      Process parameters pertaining to welding similar and dissimilar metals using explosives are reviewed. The discussion centers on the interrelationship of physical parameters which play a part in achieving desirable metallurgical results. Present activities in explosion metal welding at LASL are presented and shown how they related to the interests of the ERDA community

    7. Ion implantation of metals

      International Nuclear Information System (INIS)

      Dearnaley, G.

      1976-01-01

      In this part of the paper descriptions are given of the effects of ion implantation on (a) friction and wear in metals; and (b) corrosion of metals. In the study of corrosion, ion implantation can be used either to introduce a constituent that is known to convey corrosion resistance, or more generally to examine the parameters which control corrosion. (U.K.)

    8. Marks of Metal

      DEFF Research Database (Denmark)

      2015-01-01

      Udstilling på Mediemuseet med fokus på den visuelle side af heavy metal: Logoer, pladecovers og lignende.......Udstilling på Mediemuseet med fokus på den visuelle side af heavy metal: Logoer, pladecovers og lignende....

    9. Liquid metals pumping

      International Nuclear Information System (INIS)

      Le Frere, J.P.

      1984-01-01

      Pumps used to pump liquid metals depend on the liquid metal and on the type of application concerned. One deals more particularly with electromagnetic pumps, the main pumps used with mechanical pumps. To pump sodium in the nuclear field, these two types of pumps are used; the pumps of different circuits of Super Phenix are presented and described [fr

    10. PRODUCTION OF PLUTONIUM METAL

      Science.gov (United States)

      Lyon, W.L.; Moore, R.H.

      1961-01-17

      A process is given for producing plutonium metal by the reduction of plutonium chloride, dissolved in alkali metal chloride plus or minus aluminum chloride, with magnesium or a magnesium-aluminum alloy at between 700 and 800 deg C and separating the plutonium or plutonium-aluminum alloy formed from the salt.

    11. Liquid metal monitor

      International Nuclear Information System (INIS)

      Caldwell-Nichols, C.J.; Roach, P.F.

      1982-01-01

      A liquid metal monitor of the by-pass plugging meter kind described in British Patent 1,308,466, is further provided with a pump arranged to oppose flow through a by-pass thereby to provide a constant pressure difference across an orifice and improve the sensitivity of the instrument. The monitor estimates the impurity content in a liquid metal stream. (author)

    12. Extraction of metal values

      Energy Technology Data Exchange (ETDEWEB)

      Dalton, R F

      1988-10-19

      Metal values (especially uranium values) are extracted from aqueous solutions of metal oxyions in the absence of halogen ion using an imidazole of defined formula. Especially preferred extractants are 1-alkyl imidazoles and benzimidazoles having from 7 to 25 carbon atoms in the alkyl group.

    13. Liquid metal purification device

      International Nuclear Information System (INIS)

      Sakai, Takao; Shimoyashiki, Shigehiro.

      1992-01-01

      The device of the present invention concerns a liquid metal purification device for removing and purifying impuries in liquid metal sodium used as coolants of an FBR type reactor. A vessel having a group of pipes made of hydrogen permeable metal at the inside thereof is disposed to the inlet pipeline of a cold trap. The group of hydrogen permeable metal pipes is connected to an exhaust pipe and a vacuum pump, so that the inside of the pipes is exhausted. Liquid metal sodium branched from the main pipeline of a coolant system passes through the outer side of the group of the hydrogen permeable metal pipes. In this cae, hydrogen contained as impurities in the liquid metal sodium diffuses and permeates the hydrogen permeation metal pipes and enters into the pipe group and is discharged out of the system by the vacuum pump. This can mitigate the hydrogen removing burden of the cold trap, to extend the device life time. (I.N.)

    14. Superconductivity in bad metals

      International Nuclear Information System (INIS)

      Emery, V.J.; Kivelson, S.A.

      1995-01-01

      It is argued that many synthetic metals, including high temperature superconductors are ''bad metals'' with such a poor conductivity that the usual mean-field theory of superconductivity breaks down because of anomalously large classical and quantum fluctuations of the phase of the superconducting order parameter. Some consequences for high temperature superconductors are described

    15. Metals and Neurodegeneration

      Science.gov (United States)

      Chen, Pan; Miah, Mahfuzur Rahman; Aschner, Michael

      2016-01-01

      Metals play important roles in the human body, maintaining cell structure and regulating gene expression, neurotransmission, and antioxidant response, to name a few. However, excessive metal accumulation in the nervous system may be toxic, inducing oxidative stress, disrupting mitochondrial function, and impairing the activity of numerous enzymes. Damage caused by metal accumulation may result in permanent injuries, including severe neurological disorders. Epidemiological and clinical studies have shown a strong correlation between aberrant metal exposure and a number of neurological diseases, including Alzheimer’s disease, amyotrophic lateral sclerosis, autism spectrum disorders, Guillain–Barré disease, Gulf War syndrome, Huntington’s disease, multiple sclerosis, Parkinson’s disease, and Wilson’s disease. Here, we briefly survey the literature relating to the role of metals in neurodegeneration. PMID:27006759

    16. Production of magnesium metal

      Science.gov (United States)

      Blencoe, James G [Harriman, TN; Anovitz, Lawrence M [Knoxville, TN; Palmer, Donald A [Oliver Springs, TN; Beard, James S [Martinsville, VA

      2010-02-23

      A process of producing magnesium metal includes providing magnesium carbonate, and reacting the magnesium carbonate to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The carbon dioxide is used as a reactant in a second process. In another embodiment of the process, a magnesium silicate is reacted with a caustic material to produce magnesium hydroxide. The magnesium hydroxide is reacted with a source of carbon dioxide to produce magnesium carbonate. The magnesium carbonate is reacted to produce a magnesium-containing compound and carbon dioxide. The magnesium-containing compound is reacted to produce magnesium metal. The invention further relates to a process for production of magnesium metal or a magnesium compound where an external source of carbon dioxide is not used in any of the reactions of the process. The invention also relates to the magnesium metal produced by the processes described herein.

    17. Chelation in Metal Intoxication

      Directory of Open Access Journals (Sweden)

      Swaran J.S. Flora

      2010-06-01

      Full Text Available Chelation therapy is the preferred medical treatment for reducing the toxic effects of metals. Chelating agents are capable of binding to toxic metal ions to form complex structures which are easily excreted from the body removing them from intracellular or extracellular spaces. 2,3-Dimercaprol has long been the mainstay of chelation therapy for lead or arsenic poisoning, however its serious side effects have led researchers to develop less toxic analogues. Hydrophilic chelators like meso-2,3-dimercaptosuccinic acid effectively promote renal metal excretion, but their ability to access intracellular metals is weak. Newer strategies to address these drawbacks like combination therapy (use of structurally different chelating agents or co-administration of antioxidants have been reported recently. In this review we provide an update of the existing chelating agents and the various strategies available for the treatment of heavy metals and metalloid intoxications.

    18. Method of producing homogeneous mixed metal oxides and metal-metal oxide mixtures

      International Nuclear Information System (INIS)

      Quinby, T.C.

      1980-01-01

      A method for preparing particulate metal or metal oxide of controlled partile size comprises contacting an an aqueous solution containing dissolved metal values with excess urea at a temperature sufficient to cause urea to react with water to provide a molten urea solution containing the metal values; heating the molten urea solution to cause the metal values to precipitate, forming a mixture containing precipitated metal values; heating the mixture containing precipitated metal values to evaporate volatile material leaving a dry powder containing said metal values. The dry powder can be calcined to provide particulate metal oxide or reduced to provide particulate metal. Oxide mixtures are provided when the aqueous solution contains values of more than one metal. Homogeneousmetal-metal oxide mistures for preparing cermets can be prepared by selectively reducing at least one of the metal oxides. (auth)

    19. Ansiedade no período pré-operatório de cirurgias de mama: estudo comparativo entre pacientes com suspeita de câncer e a serem submetidas a procedimentos cirúrgicos estéticos Ansiedad en el período preoperatorio de cirugías de mama: estudio comparativo entre pacientes con sospecha de cáncer a ser sometidas a procedimientos quirúrgicos estéticos Preoperative anxiety in surgeries of the breast: a comparative study between patients with suspected breast cancer and that undergoing cosmetic surgery

      Directory of Open Access Journals (Sweden)

      Maria Luiza Melo Alves

      2007-04-01

      ón de la ansiedad no forma parte de la rutina de la evaluación preanestésica (APA, lo que hace que situaciones especiales en que el estado emocional de los pacientes pueda estar alterado pasen desapercibidas por el anestesiólogo. Este estudio quiso comparar al momento de la APA ambulatorial, factores de riesgo, intensidad y prevalencia de ansiedad en pacientes con sospecha de cáncer de mama a ser sometidas a procedimientos quirúrgicos estéticos de mama. MÉTODO: Después de la aprobación por el Comité de Ética, fueron estudiadas en el ambulatorio de APA, 114 pacientes, ASA I o II, edad > 14 años, divididas en los grupos: GMAMA - pacientes con sospecha de cáncer de mama; GPLAST - pacientes a ser sometidas a cirugía plástica estética. Después del consentimiento aclarado, las pacientes respondieron al la prueba de evaluación de ansiedad (IDATE - Inventario de Ansiedad Trazo-Estado antes de la evaluación preanestésica. Se analizaron: datos sociodemográficos; experiencia con procedimientos quirúrgicos anteriores; número y porcentaje de pacientes con ansiedad baja, moderada y alta (IDATE I y II; promedio de los puntajes de las escalas IDATE I y II. RESULTADOS: Los grupos fueron homogéneos en relación a los datos sociodemográficos y experiencia con procedimientos quirúrgicos anteriores. Se observó diferencia significativa de los niveles y prevalencia de ansiedad-estado (IDATE I. No fueron identificados factores de riesgo para ansiedad-estado y ansiedad-trazo. CONCLUSIONES: Las pacientes con sospecha de cáncer de mama a ser sometidas a la retirada de nódulo o tejido mamario para diagnóstico presentaron niveles y prevalencia de ansiedad-estado alta mayores que las pacientes a ser sometidas a mamoplastías; los niveles y la prevalencia de ansiedad-trazo fueron similares en los de los grupos y no fueron identificados factores de riesgo para ansiedad-estado y ansiedad-trazo.BACKGROUND AND OBJECTIVES: Evaluation of anxiety is not part of the routine pre

    20. Nanoporous metal-carbon composite

      Science.gov (United States)

      Worsley, Marcus A.; Satcher, Joe; Kucheyev, Sergei; Charnvanichborikarn, Supakit; Colvin, Jeffrey; Felter, Thomas; Kim, Sangil; Merrill, Matthew; Orme, Christine

      2017-12-19

      Described here is a metal-carbon composite, comprising (a) a porous three-dimensional scaffold comprising one or more of carbon nanotubes, graphene and graphene oxide, and (b) metal nanoparticles disposed on said porous scaffold, wherein the metal-carbon composite has a density of 1 g/cm.sup.3 or less, and wherein the metal nanoparticles account for 1 wt. % or more of the metal-carbon composite. Also described are methods for making the metal-carbon composite.

    1. Method for producing metallic nanoparticles

      Science.gov (United States)

      Phillips, Jonathan; Perry, William L.; Kroenke, William J.

      2004-02-10

      Method for producing metallic nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating non-oxidizing plasma with a plasma hot zone at a temperature sufficiently high to vaporize the microparticles into metal vapor, and directing the aerosol into the hot zone of the plasma. The microparticles vaporize in the hot zone to metal vapor. The metal vapor is directed away from the hot zone and to the plasma afterglow where it cools and condenses to form solid metallic nanoparticles.

    2. Method for producing metallic microparticles

      Science.gov (United States)

      Phillips, Jonathan; Perry, William L.; Kroenke, William J.

      2004-06-29

      Method for producing metallic particles. The method converts metallic nanoparticles into larger, spherical metallic particles. An aerosol of solid metallic nanoparticles and a non-oxidizing plasma having a portion sufficiently hot to melt the nanoparticles are generated. The aerosol is directed into the plasma where the metallic nanoparticles melt, collide, join, and spheroidize. The molten spherical metallic particles are directed away from the plasma and enter the afterglow where they cool and solidify.

    3. A double metal process

      International Nuclear Information System (INIS)

      Hawley, F.; Vasche, G.; Caywood, J.M.; Houck, B.; Boyce, J.; Tso, L.

      1988-01-01

      A dual layer metallization process is studied using a Tungsten 10% Titanium/Molybdenum sandwich (TiW/Mo) first metal with an Al/.5% Cu for the second metal. This metallization process has: 1) very reliable shallow junction contacts without junction spiking, 2) very high electromigration resistance and (3) A very smooth defect free surface throughout the process. Contact resistance of 50 and 30 ohm-um2 for P and N type silicon respectively is achieved. The TiW/Mo film stress is studied and an optimum condition for low compressive stress is defined. The TiW/Mo is etched using a corrosion free etch process. Electromigration data is presented showing TiW/Mo to be at least an order of magnitude better than Al/Si. The intermetal oxide layer is a planarized sandwich of LTO/SOG/LTO providing a smooth positive slope surface for the Metal 2. Metal l/Metal 2 via resistances are studied with 1.25 ohm-um2 values obtained

    4. Actinide metal processing

      International Nuclear Information System (INIS)

      Sauer, N.N.; Watkin, J.G.

      1992-01-01

      A process for converting an actinide metal such as thorium, uranium, or plutonium to an actinide oxide material by admixing the actinide metal in an aqueous medium with a hypochlorite as an oxidizing agent for sufficient time to form the actinide oxide material and recovering the actinide oxide material is described together with a low temperature process for preparing an actinide oxide nitrate such as uranyl nitrate. Additionally, a composition of matter comprising the reaction product of uranium metal and sodium hypochlorite is provided, the reaction product being an essentially insoluble uranium oxide material suitable for disposal or long term storage

    5. Metal recovery via geobiotechnology

      International Nuclear Information System (INIS)

      Hedrich, Sabrina; Schippers, Axel

      2017-01-01

      Specialized acidophilic bacteria and archaea are able to extract valuable metals such as copper, gold, cobalt, nickel, zinc, and uranium from sulfide ores. This process is known as bioleaching and its application in the mining industry as biomining. Laboratory studies also demonstrated bioleaching of oxide ores such as laterites and of mining residues such as mine tailings as well as metal recycling from waste (secondary mining). Metals being leached have to be recovered from acidic polymetallic solutions (mine and process waters) which is possible via biosorption or biomineralisation.

    6. Metal Detecting in Denmark

      DEFF Research Database (Denmark)

      Dobat, A.S.

      2016-01-01

      questions: 1) Why does the liberal model work in Denmark, 2) which downsides of the liberal model of metal detector archaeology in Denmark can be identified, 30 years after its inception the beginning, and 3) what are possible solutions to these problems. It will be argued that a user-driven national...... all of the spectacular and ground-breaking discoveries of the past decades are owed to metal detectors in the hands of amateur archaeologists. In order to serve as a contribution to the discussion on the upsides and downsides of liberal metal detector archaeology, this article addresses mainly three...

    7. Fabrication of Metallic Hollow Nanoparticles

      Science.gov (United States)

      Kim, Jae-Woo (Inventor); Choi, Sr., Sang H. (Inventor); Lillehei, Peter T. (Inventor); Chu, Sang-Hyon (Inventor); Park, Yeonjoon (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor)

      2016-01-01

      Metal and semiconductor nanoshells, particularly transition metal nanoshells, are fabricated using dendrimer molecules. Metallic colloids, metallic ions or semiconductors are attached to amine groups on the dendrimer surface in stabilized solution for the surface seeding method and the surface seedless method, respectively. Subsequently, the process is repeated with additional metallic ions or semiconductor, a stabilizer, and NaBH.sub.4 to increase the wall thickness of the metallic or semiconductor lining on the dendrimer surface. Metallic or semiconductor ions are automatically reduced on the metallic or semiconductor nanoparticles causing the formation of hollow metallic or semiconductor nanoparticles. The void size of the formed hollow nanoparticles depends on the dendrimer generation. The thickness of the metallic or semiconductor thin film around the dendrimer depends on the repetition times and the size of initial metallic or semiconductor seeds.

    8. Metalcasting: Filtering Molten Metal

      International Nuclear Information System (INIS)

      Lauren Poole; Lee Recca

      1999-01-01

      A more efficient method has been created to filter cast molten metal for impurities. Read about the resulting energy and money savings that can accrue to many different industries from the use of this exciting new technology

    9. Micro metal forming

      CERN Document Server

      2013-01-01

      Micro Metal Forming, i. e. forming of parts and features with dimensions below 1 mm, is a young area of research in the wide field of metal forming technologies, expanding the limits for applying metal forming towards micro technology. The essential challenges arise from the reduced geometrical size and the increased lot size. In order to enable potential users to apply micro metal forming in production, information about the following topics are given: tribological behavior: friction between tool and work piece as well as tool wear mechanical behavior: strength and formability of the work piece material, durability of the work pieces size effects: basic description of effects occurring due to the fact, that the quantitative relation between different features changes with decreasing size process windows and limits for forming processes tool making methods numerical modeling of processes and process chains quality assurance and metrology All topics are discussed with respect to the questions relevant to micro...

    10. Ferrous Metal Processing Plants

      Data.gov (United States)

      Department of Homeland Security — This map layer includes ferrous metal processing plants in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

    11. Nonferrous Metal Processing Plants

      Data.gov (United States)

      Department of Homeland Security — This map layer includes nonferrous metal processing plants in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...

    12. Coating of metals

      International Nuclear Information System (INIS)

      Smith, F.

      1978-01-01

      A method is described for coating the surface of an article of Ti, Zr or Ta, or an alloy thereof, with a tinning metal or alloy, the article having a shape other than that of a sheet. The method comprises contacting the surface of the article at an elevated temperature with the molten tinning metal and moving an ultrasonically excited probe over the surface to be coated, the probe being in contact with the surface of the article and with the tinning metal. The tinning metal may be Sn or Zn or a binary alloy of Sn with Zn, Cd or Bi at a temperature of 300 0 to 450 0 C. The head of the probe may be shaped to conform with the surface of the article. The method may be used to form composite articles, and may be applied to a pre-tinned steel article. (U.K.)

    13. Oligocyclopentadienyl transition metal complexes

      Energy Technology Data Exchange (ETDEWEB)

      de Azevedo, Cristina G.; Vollhardt, K. Peter C.

      2002-01-18

      Synthesis, characterization, and reactivity studies of oligocyclopentadienyl transition metal complexes, namely those of fulvalene, tercyclopentadienyl, quatercyclopentadienyl, and pentacyclopentadienyl(cyclopentadienyl) are the subject of this account. Thermal-, photo-, and redox chemistries of homo- and heteropolynuclear complexes are described.

    14. Crystalline structure of metals

      International Nuclear Information System (INIS)

      Holas, A.

      1972-01-01

      An attempt is made to find the crystalline structure of metals on the basis of the existing theory of metals. The considerations are limited to the case of free crystals, that is, not subjected to any stresses and with T=0. The energy of the crystal lattice has been defined and the dependence of each term on structures and other properties of metals has been described. The energy has been used to find the values of crystalline structure parameters as the values at which the energy has an absolute minimum. The stability of the structure has been considered in cases of volume changes and shearing deformations. A semiqualitative description has been obtained which explains characteristic properties of one-electron metals. (S.B.)

    15. Plutonium metal burning facility

      International Nuclear Information System (INIS)

      Hausburg, D.E.; Leebl, R.G.

      1977-01-01

      A glove-box facility was designed to convert plutonium skull metal or unburned oxide to an oxide acceptable for plutonium recovery and purification. A discussion of the operation, safety aspects, and electrical schematics are included

    16. Genotoxicity of metal nanoparticles.

      Science.gov (United States)

      Xie, Hong; Mason, Michael M; Wise, John Pierce

      2011-01-01

      Nanotechnology is currently used in industry, medicine, and military applications, as well as in more than 300 commercial products. Yet, the same properties that make these particles exciting for technology also make them daunting public health concerns because their toxicity is unknown and relatively unexplored. Increased attention is being placed on the study of metal particle genotoxicity; however, a lot of unknowns remain about their effects and the mechanisms. In this article, we highlight some metal and metal oxide nanoparticles of interest and discuss the current in vivo and in vitro studies of genotoxic effects. Many metal nanoparticles were found to cause chromosomal aberrations, DNA strand breaks, oxidative DNA damage, and mutations. Inconsistencies are found in the literature, however, thus drawing conclusions is difficult due to a variety of factors. Therefore, the areas requiring further attention are highlighted and recommendations to improve our understanding of the genotoxic potential are addressed.

    17. Novel Metals and Metal Complexes as Platforms for Cancer Therapy

      OpenAIRE

      Frezza, Michael; Hindo, Sarmad; Chen, Di; Davenport, Andrew; Schmitt, Sara; Tomco, Dajena; Dou, Q. Ping

      2010-01-01

      Metals are essential cellular components selected by nature to function in several indispensable biochemical processes for living organisms. Metals are endowed with unique characteristics that include redox activity, variable coordination modes, and reactivity towards organic substrates. Due to their reactivity, metals are tightly regulated under normal conditions and aberrant metal ion concentrations are associated with various pathological disorders, including cancer. For these reasons, coo...

    18. Metallic composite materials

      International Nuclear Information System (INIS)

      Frommeyer, G.

      1987-01-01

      The structure and properties of metallic composite materials and composite materials with metallic matrix are considered. In agreement with the morphology of constituent phases the following types of composite materials are described: dispersion-strengthened composite materials; particle-reinforced composite materials; fibrous composite materials; laminar composite materials. Data on strength and electric properties of the above-mentioned materials, as well as effect of the amount, location and geometric shape of the second phase on them, are presented

    19. PRODUCTION OF HAFNIUM METAL

      Science.gov (United States)

      Elger, G.W.; Boubel, R.W.

      1963-01-01

      This patent deals with a process of producing pure Hf metal from oxygen- contaminated gaseous Hf chloride. The oxygen compounds in the chioride gas are halogenated by contacting the gas at elevated temperature with Cl/sub 2/ in the presence of C. The Hf chloride, still in gaseous form, is contacted with molten Mg whereby Hf metal is formed and condensed on the Mg. (AEC)

    20. Radiation effects in metals

      International Nuclear Information System (INIS)

      Leteurtre Jean.

      1978-01-01

      The current understanding of radiation damage in metals is reviewed, simplifying the actual complexity of the effects by considering some aspects separately. The production of point defects in metals, the primary damage state are first studied. The second part of the lecture is devoted to the evolution of this primary damage state as a function of temperature and dose: the steady state concentration of point defects, the nucleation of secondary defects and their growth are successively considered

    1. Metal pollution (Pb, Zn, Ni and Cr) in air, road and soil sediment in a high traffic area; Contaminacion por metales (Pb, Zn, Ni y Cr) en aire, sedimentos viales y suelo en una zona de alto trafico vehicular

      Energy Technology Data Exchange (ETDEWEB)

      Manchado, Anali; Garcia, Neyma; Garcia, Cezar; Acosta, Lorena; Cordova, Alberto; Linares, Maria; Giraldoth, Debora [Centro de Investigaciones CEDEGAS, Facultad de Ingenieria, Universidad del Zulia, Maracaibo (Venezuela)]. E-mail: analimachado@yahoo.com; amachadop@luz.edu.ve; Velasquez, Harvi [Facultad Experimental de Ciencias, Universidad del Zulia, Maracaibo (Venezuela)

      2008-11-15

      sequia y de lluvia, empleando un muestreador de bajo volumen con filtros de fibra de cuarzo -para las muestras de PM10- con una frecuencia de una muestra cada tres dias para un total de 26; para los sedimentos viales y suelo fueron colectadas tres muestras con una frecuencia de 15 dias para un periodo de medicion de mes y medio en epoca seca. Todas las muestras fueron sometidas a un proceso de digestion y analizadas por espectrometria de absorcion atomica. Las concentraciones de las PM10 resultaron 2 veces mas altas en la zona de emision que en la zona de dispersion durante ambas epocas climatologicas, presentando una mejor correlacion entre las zonas para epoca de sequia. Todos los metales analizados presentaron diferencias estadisticamente significativas entre las zonas de muestreo. Por otra parte, para el periodo global existen diferencias significativas entre las zonas y las epocas climatologicas tanto para PM10 como para la totalidad de los metales. El Pb no excedio el estandar de calidad del aire establecido para Venezuela, pero su concentracion promedio en la zona de emision fue de 1.13 {mu}g/m{sup 3}, muy cercano al limite diario permitido en Venezuela y por la EPA; por su parte, tanto Pb como Ni sobrepasaron el limite permisible de la Organizacion Mundial de la Salud (OMS) en ambas zonas durante todo el periodo de muestreo. Para las muestras de sedimento y de suelo se encontraron concentraciones significativamente elevadas de Pb, Zn, Ni y Cr en comparacion con la muestra testigo. Los niveles hallados de Pb y Zn estan por encima de los limites permitidos por el decreto 2635 de la normativa venezolana y la EPA, clasificandose la zona como suelo con alta contaminacion por metales pesados. Adicionalmente, el analisis estadistico demostro la adecuada seleccion de la zona de monitoreo, confirmando que la principal fuente de emision de los contaminantes es el parque automotor.

    2. Magnetic susceptibility of 244Cm metal and 249Cf metal

      International Nuclear Information System (INIS)

      Fujita, D.K.; Parsons, T.C.; Edelstein, N.; Noe, M.; Peterson, J.R.

      1975-07-01

      The first magnetic susceptibility measurements made on the expanded fcc phase of 249 Cf metal are reported. Further measurements are needed on other Cf metal phases. Another measurement of the magnetic susceptibility of 244 Cm metal in a limited temperature range has been reported. The result does not agree with previously reported values. Further work is continuing on the synthesis of 244 Cm metal and 248 Cm metal and magnetic measurements on these samples. (auth)

    3. Porous metal for orthopedics implants

      OpenAIRE

      Matassi, Fabrizio; Botti, Alessandra; Sirleo, Luigi; Carulli, Christian; Innocenti, Massimo

      2013-01-01

      Porous metal has been introduced to obtain biological fixation and improve longevity of orthopedic implants. The new generation of porous metal has intriguing characteristics that allows bone healing and high osteointegration of the metallic implants. This article gives an overview about biomaterials properties of the contemporary class of highly porous metals and about the clinical use in orthopaedic surgery.

    4. Metallic materials for medical use

      OpenAIRE

      Illarionov Anatoly; Belikov Sergey; Grib Stella; Yurovskikh Artem

      2017-01-01

      This article provides a brief overview of the metallic materials used as implants in orthopedics, the alloying system and a complex of the physical-mechanical properties for metallic materials certified for medical use, as well as the advantages and drawbacks of using metallic materials as implants. Approaches to improve the quality of an implant made of metallic materials are noted.

    5. Metal-insulator transitions

      Science.gov (United States)

      Imada, Masatoshi; Fujimori, Atsushi; Tokura, Yoshinori

      1998-10-01

      Metal-insulator transitions are accompanied by huge resistivity changes, even over tens of orders of magnitude, and are widely observed in condensed-matter systems. This article presents the observations and current understanding of the metal-insulator transition with a pedagogical introduction to the subject. Especially important are the transitions driven by correlation effects associated with the electron-electron interaction. The insulating phase caused by the correlation effects is categorized as the Mott Insulator. Near the transition point the metallic state shows fluctuations and orderings in the spin, charge, and orbital degrees of freedom. The properties of these metals are frequently quite different from those of ordinary metals, as measured by transport, optical, and magnetic probes. The review first describes theoretical approaches to the unusual metallic states and to the metal-insulator transition. The Fermi-liquid theory treats the correlations that can be adiabatically connected with the noninteracting picture. Strong-coupling models that do not require Fermi-liquid behavior have also been developed. Much work has also been done on the scaling theory of the transition. A central issue for this review is the evaluation of these approaches in simple theoretical systems such as the Hubbard model and t-J models. Another key issue is strong competition among various orderings as in the interplay of spin and orbital fluctuations. Experimentally, the unusual properties of the metallic state near the insulating transition have been most extensively studied in d-electron systems. In particular, there is revived interest in transition-metal oxides, motivated by the epoch-making findings of high-temperature superconductivity in cuprates and colossal magnetoresistance in manganites. The article reviews the rich phenomena of anomalous metallicity, taking as examples Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Ru compounds. The diverse phenomena include strong spin and

    6. Metal ion transporters and homeostasis.

      OpenAIRE

      Nelson, N

      1999-01-01

      Transition metals are essential for many metabolic processes and their homeostasis is crucial for life. Aberrations in the cellular metal ion concentrations may lead to cell death and severe diseases. Metal ion transporters play a major role in maintaining the correct concentrations of the various metal ions in the different cellular compartments. Recent studies of yeast mutants revealed key elements in metal ion homeostasis, including novel transport systems. Several of the proteins discover...

    7. Peroxotitanates for Biodelivery of Metals

      Energy Technology Data Exchange (ETDEWEB)

      Hobbs, David; Elvington, M.

      2009-02-11

      Metal-based drugs are largely undeveloped in pharmacology. One limiting factor is the systemic toxicity of metal-based compounds. A solid-phase, sequestratable delivery agent for local delivery of metals could reduce systemic toxicity, facilitating new drug development in this nascent area. Amorphous peroxotitanates (APT) are ion exchange materials with high affinity for several heavy metal ions, and have been proposed to deliver or sequester metal ions in biological contexts. In the current study, we tested a hypothesis that APT are able to deliver metals or metal compounds to cells. We exposed fibroblasts (L929) or monocytes (THP1) to metal-APT materials for 72 h in vitro, then measured cellular mitochondrial activity (SDH-MTT method) to assess the biological impact of the metal-APT materials vs. metals or APT alone. APT alone did not significantly affect cellular mitochondrial activity, but all metal-APT materials suppressed the mitochondrial activity of fibroblasts (by 30-65% of controls). The concentration of metal-APT materials required to suppress cellular mitochondrial activity was below that required for metals alone, suggesting that simple extracellular release of the metals from the metal-APT materials was not the primary mechanism of mitochondrial suppression. In contrast to fibroblasts, no metal-APT material had a measurable effect on THP1 monocyte mitochondrial activity, despite potent suppression by metals alone. This latter result suggested that 'biodelivery' by metal-APT materials may be cell type-specific. Therefore, it appears that APT are plausible solid phase delivery agents of metals or metal compounds to some types of cells for potential therapeutic effect.

    8. Separations chemistry of toxic metals

      International Nuclear Information System (INIS)

      Smith, P.; Barr, M.; Barrans, R.

      1996-01-01

      Sequestering and removing toxic metal ions from their surroundings is an increasingly active area of research and is gaining importance in light of current environmental contamination problems both within the DOE complex and externally. One method of separating metal ions is to complex them to a molecule (a ligand or chelator) which exhibits specific binding affinity for a toxic metal, even in the presence of other more benign metals. This approach makes use of the sometimes subtle differences between toxic and non-toxic metals resulting from variations in size, charge and shape. For example, toxic metals such as chromium, arsenic, and technetium exist in the environment as oxyanions, negatively charged species with a characteristic tetrahedral shape. Other toxic metals such as actinides and heavy metals are positively charged spheres with specific affinities for particular donor atoms such as oxygen (for actinides) and nitrogen (for heavy metals). In most cases the toxic metals are found in the presence of much larger quantities of less toxic metals such as sodium, calcium and iron. The selectivity of the chelators is critical to the goal of removing the toxic metals from their less toxic counterparts. The approach was to build a ligand framework that complements the unique characteristics of the toxic metal (size, charge and shape) while minimizing interactions with non-toxic metals. The authors have designed ligands exhibiting specificity for the target metals; they have synthesized, characterized and tested these ligands; and they have shown that they exhibit the proposed selectivity and cooperative binding effects

    9. Polyamorphism in metalic glass.

      Energy Technology Data Exchange (ETDEWEB)

      Sheng, H. W.; Liu, H. Z.; Cheng, Y. Q.; Wen, J.; Lee, P.L.; Luo, W.K.; Shastri, S.D.; Ma, E.; X-Ray Science Division; Johns Hopkins Univ.; Chinese Academy of Sciences

      2007-03-01

      A metal, or an alloy, can often exist in more than one crystal structure. The face-centered-cubic and body-centered-cubic forms of iron (or steel) are a familiar example of such polymorphism. When metallic materials are made in the amorphous form, is a parallel 'polyamorphism' possible? So far, polyamorphic phase transitions in the glassy state have been observed only in glasses involving directional and open (such as tetrahedral) coordination environments. Here, we report an in situ X-ray diffraction observation of a pressure-induced transition between two distinct amorphous polymorphs in a Ce{sub 55}Al{sub 45} metallic glass. The large density difference observed between the two polyamorphs is attributed to their different electronic and atomic structures, in particular the bond shortening revealed by ab initio modeling of the effects of f-electron delocalization. This discovery offers a new perspective of the amorphous state of metals, and has implications for understanding the structure, evolution and properties of metallic glasses and related liquids. Our work also opens a new avenue towards technologically useful amorphous alloys that are compositionally identical but with different thermodynamic, functional and rheological properties due to different bonding and structural characteristics.

    10. Metals in edible seaweed.

      Science.gov (United States)

      Rubio, C; Napoleone, G; Luis-González, G; Gutiérrez, A J; González-Weller, D; Hardisson, A; Revert, C

      2017-04-01

      The concentration levels of 20 metals were analyzed by ICP-OES in edible seaweed (Chondrus, Eisenia, Gelidium, Himanthalia, Laminaria, Palmaria, Porphyra, Undaria), from two origins (Asia vs EU) according to their cultivation practices (conventional vs organic). Red seaweed showed higher concentrations of trace and toxic elements. Porphyra may be used as a potential bioindicator for metals. Significant differences were found between the Asian vs European mean contents. The mean Cd level from the conventional cultivation (0.28 mg/kg) was two points higher than the organic cultivation (0.13 mg/kg). A daily consumption of seaweed (4 g/day) contributes to the dietary intake of metals, mainly Mg and Cr. The average intakes of Al, Cd and Pb were 0.064, 0.001 and 0.0003 mg/day, respectively. Based on obtained results, this study suggests that exposure to the toxic metals analyzed (Al, Cd and Pb) through seaweed consumption does not raise serious health concerns, but other toxic metals should be monitored. Copyright © 2017. Published by Elsevier Ltd.

    11. Novel Ammonium Metal Borohydrides

      DEFF Research Database (Denmark)

      Grinderslev, Jakob; Jepsen, Lars Haahr; Cerny, Radovan

      , it cannot store hydrogen reversibly. Recently, the first ammonium metal borohydride, NH4Ca(BH4)3 was published, which may be considered as substitution of K+ by NH4+ in KCa(BH4)3, due to the similar sizes of NH4+ and K+[1]. This compound successfully stabilizes NH4BH4. In the present work, a series of novel...... halide-free ammonium metal borohydrides is presented, which have the chemical compositions (NH4)xM(BH4)n+x. The ammonium metal borohydrides are synthesized by cryomilling of NH4BH4 – M(BH4)n (M = Li, Na, K, Mg, Sr, Y, Mn, La, Gd) in different ratios. A new range of ammonium metal borohydrides is formed......, and the crystal structures and thermal decompositions are investigated. Mixtures of NH4BH4 - NaBH4 do not react, while solid solutions, K1-x(NH4)xBH4, are formed for NH4BH4 - KBH4. For the other composites, novel ammonium metal borohydrides are formed. Several of these structures have been solved from high...

    12. Análisis de vigas curvas rigidizadas longitudinalmente sometidas a cargas concentradas

      OpenAIRE

      Navarro Delgado, Ana

      2016-01-01

      El trabajo final de máster consiste en el prototipado, análisis y desarrollo experimental y numérico de herramientas de bajo coste y acceso libre que permitan controlar los procesos de lanzamiento de puentes por empujes sucesivos en estructuras metálicas. Se utilizan tanto hardware como software libre y se utilizan herramientas de impresión 3D como soporte. Actualmente hay una gran variedad de procesos constructivos para la construcción de puentes. Uno muy utilizado tanto por sus venta...

    13. Desarrollo radical en plantas de duraznero sometidas a diferentes manejos del suelo

      Directory of Open Access Journals (Sweden)

      GONZALEZ, J.1;

      2012-10-01

      Full Text Available El objetivo de este trabajo fue evaluar la incidencia del sistema de manejo y la textura del suelo sobre el desarrollo del sistema radicular y el diámetro de tronco del duraznero cv Dixiland cultivado sobre un Argiudol vértico de la Serie Ramallo bajo condiciones de secano, en el norte de la provincia de Buenos Aires, Argentina.Se ensayó con tres sistemas de manejo del suelo: labores mecánicas, sin labranza con control químico de malezas y cobertura vegetal. Se caracterizó la distribución de raíces en sentido horizontal y vertical por medio del número de raíces obtenido con el método de “trinchera”. Se determinó la densidad aparente con el método del cilindro, la textura de los horizontes del suelo hasta los 75 cm de profundidad y el diámetro de tronco.Los resultados obtenidos mostraron que, tanto el laboreo mecánico como el no laboreo del suelo con control químico de malezas, están asociados a un mayor desarrollo del diámetro del tronco y del sistema radicular en los primeros 40 cm. de profundidad respecto del tratamiento con cobertura vegetal. El desarrollo del estratosuperficial de raíces se ve restringido, tanto por el laboreo mecánico como por la cobertura vegetal del sueloy la textura explica su desarrollo en profundidad.

    14. Additive manufacturing of metals

      International Nuclear Information System (INIS)

      Herzog, Dirk; Seyda, Vanessa; Wycisk, Eric; Emmelmann, Claus

      2016-01-01

      Additive Manufacturing (AM), the layer-by layer build-up of parts, has lately become an option for serial production. Today, several metallic materials including the important engineering materials steel, aluminium and titanium may be processed to full dense parts with outstanding properties. In this context, the present overview article describes the complex relationship between AM processes, microstructure and resulting properties for metals. It explains the fundamentals of Laser Beam Melting, Electron Beam Melting and Laser Metal Deposition, and introduces the commercially available materials for the different processes. Thereafter, typical microstructures for additively manufactured steel, aluminium and titanium are presented. Special attention is paid to AM specific grain structures, resulting from the complex thermal cycle and high cooling rates. The properties evolving as a consequence of the microstructure are elaborated under static and dynamic loading. According to these properties, typical applications are presented for the materials and methods for conclusion.

    15. Functional memory metals

      International Nuclear Information System (INIS)

      Dunne, D.P.

      2000-01-01

      The field of shape memory phenomena in metals and alloys has developed in a sporadic fashion from a scientific curiosity to a vigorously growing niche industry, over a period close to a full working lifetime. Memory metal research and development is replete with scientist and engineer 'true believers', who can finally feel content that their longstanding confidence in the potential of these unusual functional materials has not been misplaced. This paper reviews the current range of medical and non-medical systems and devices which are based on memory metals and attempts to predict trends in applications over the next decade. The market is dominated by Ni Ti alloys which have proved to exhibit the best and most reproducible properties for application in a wide range of medical and non-medical devices

    16. Theory of normal metals

      International Nuclear Information System (INIS)

      Mahan, G.D.

      1992-01-01

      The organizers requested that I give eight lectures on the theory of normal metals, ''with an eye on superconductivity.'' My job was to cover the general properties of metals. The topics were selected according to what the students would need to known for the following lectures on superconductivity. My role was to prepare the ground work for the later lectures. The problem is that there is not yet a widely accepted theory for the mechanism which pairs the electrons. Many mechanisms have been proposed, with those of phonons and spin fluctuations having the most followers. So I tried to discuss both topics. I also introduced the tight-binding model for metals, which forms the basis for most of the work on the cuprate superconductors

    17. Metal-ligand interactions

      Science.gov (United States)

      Ervin, Kent M.

      Experimental studies of the interactions of small transition-metal cluster anions with carbonyl ligands are reviewed and compared with neutral and cationic clusters. Under thermal conditions, the reaction rates of transition-metal clusters with carbon monoxide are measured as a function of cluster size. Saturation limits for carbon monoxide addition can be related to the geometric structures of the clusters. Both energy-resolved threshold collision-induced dissociation experiments and time-resolved photodissociation experiments are used to measure metal-carbonyl binding energies. For platinum and palladium trimer anions, the carbonyl binding energies are assigned to different geometric binding sites. Platinum and palladium cluster anions catalyse the oxidation of carbon monoxide to carbon dioxide in a full catalytic cycle at thermal energies.

    18. Extinction of metal fires

      International Nuclear Information System (INIS)

      Mellottee, H.

      1977-01-01

      The main points of a large bibliography on liquid and solid metal fires are set out. The various methods used to fight these fires are presented; covering by powders is specially emphasized. Since this method has promising results, the various possible techniques, extinction by cooling the metal, by blanketing, by formation of a continuous insulating layer (by fusion or pyrolysis of a powder) or by a surface reaction between powder and metal are studied. The conditions of conservation and use of powders are outlined, then the various powders are described: inert powders, powders undergoing a physical transformation (fusion or vitrification of an organic compound, fusion of eutectic inorganic mixtures), multiple effect powders. Precise examples are quoted [fr

    19. Metal fuel safety performance

      International Nuclear Information System (INIS)

      Miles, K.J. Jr.; Tentner, A.M.

      1988-01-01

      The current development of breeder reactor systems has lead to the renewed interest in metal fuels as the driver material. Modeling efforts were begun to provide a mechanistic description of the metal fuel during anticipated and hypothetical transients within the context of the SAS4A accident analysis code system. Through validation exercises using experimental results of metal fuel TREAT tests, confidence is being developed on the nature and accuracy of the modeling and implementation. Prefailure characterization, transient pin response, margins to failure, axial in-pin fuel relocation prior to cladding breach, and molten fuel relocation after cladding breach are considered. Transient time scales ranging from milliseconds to many hours can be studied with all the reactivity feedbacks evaluated

    20. Metal-microorganism interactions

      International Nuclear Information System (INIS)

      Andres, Y.; Thouand, G.; Redercher, S.; Boualam, M.; Texier, A.Cl.; Hoeffer, R.

      1997-01-01

      The physico-chemical procedures of treating the metalliferous effluents are not always adapted to de polluting the slightly concentrated industrial wastes. An alternative idea was advanced, implying the ability of some microorganisms to fix in considerable amounts the metal ions present in aqueous solutions, possibly in a selective way. This approach has been investigated thoroughly during the last 30 years, particularly from a mechanistic point of view. The advantage of the microorganisms lies mainly in the large diversity of bacteria and in their chemical state dependent interaction with metals, as well as, in the possibilities of developing their selective and quantitative separation properties. A biomass from Mycobacterium smegmatis, an acidic alcoholic resistant bacteria, has been used to prepare a bio-sorption support allowing the preferential sorption of thorium as compared to uranium and lanthanum. These studies have been extended to biological polymers such as chitosan and to studies related to bioaccumulation mechanisms and/or to the microbial resistances towards metals

    1. Sensor for metal detection

      KAUST Repository

      Kodzius, Rimantas

      2014-06-26

      NOVELTY - The sensor has a microfluidic flow channel that is provided with an inlet port, an outlet port, and a detection chamber. The detection chamber is provided with a group of sensing electrodes (4) having a working electrode (8), a counter electrode (9), and a reference electrode (10). A flow sensor is configured to measure flow in the channel. A temperature sensor (6) is configured to measure temperature in the channel (3). An electrical connection is configured to connect the sensor to a sensing device. USE - Sensor for detecting metal such as toxic metal in sample such as clinical sample such as stool, saliva, sputum, bronchial lavage, urine, vaginal swab, nasal swab, biopsy, tissue, tears, breath, blood, serum, plasma, cerebrospinal fluid, peritoneal fluid, pleural fluid, pericardial fluid, joint fluid, and amniotic fluid, water sample, food sample, air sample, and soil sample (all claimed). ADVANTAGE - The sensor for use with the portable analytical instrument is configured for detection of metalsin samples. The sensor can provide the excellent solution for on-site metal detection, including heavy metal detection. The sensors can provide significant advantages in higher throughput, lower cost, at the same time being less labor intensive and less dependent on individual skills. The disposable design of the sensor, the enhanced reliability and repeatability of measurements can be obtained. The sensors can be widely applied in various industries. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a system for detecting metal in sample; and (2) a method for using sensor for detecting metal in sample. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the sensor prototype. Channel (3) Sensing electrodes (4) Temperature sensor (6) Working electrode (8) Counter electrode (9) Reference electrode (10)

    2. CONFLITOS ENTRE O CORPO RITUAL E O CORPO DIGITAL: NOTAS SOBRE O DOCUMENTÁRIO EXPANDIDO “MARCADORES”

      Directory of Open Access Journals (Sweden)

      Roderick Peter Steel

      2014-12-01

      Full Text Available This research project generates several installations and a critical reflection on how new technologies are changing religious practices. It examines how sacred images in the African-Brazilian religion of candomblé are being re-signified in transit between different electronic and digital media. The research aims to chart the visual documentation of the human body in trance, generated by a wide variety of different devices, as it journeys through different media. The result of this study will generate an exhibition in which a documentary film will roam freely over multiple screens in a video-installation. The study wishes to expand the boundaries between the documentation of a religious event and its reconstruction within the exhibition space, exploring multi-tiered relationships between cinema, photography, visual arts and anthropology in complex environments, in order to maximize the potential of an immersive sensory experience.

    3. Sistema constructivo de paneles aligerados con poliestireno expandido y malla electrosoldada espacial: estudio estructural y optimización

      OpenAIRE

      Cansario Pérez, Maria del Mar

      2005-01-01

      Los sistemas modernos de construcción son asociados a tecnologías innovadoras y a los nuevos materiales, sistemas livianos que ofrecen la posibilidad de una mayor rapidez de ejecución por montaje. Estas características influyen en gran medida en el aprovechamiento de los materiales y de la mano de obra, ya que la planificación se hace más sencilla, pudiendo cumplir las metas fijadas en cuanto a los recursos económicos y de tiempo. La demanda de mayor cantidad de viviendas hace necesaria la in...

    4. Metal Hypersensitivity in Orthodontic Patients

      Directory of Open Access Journals (Sweden)

      Sandhya Maheshwari Sanjeev K

      2015-06-01

      Full Text Available Orthodontic treatment of individuals with metal hypersensitivity is a matter of concern for the orthodontist. Orthodontic appliances contain metals like Nickel, Cobalt and Chromium etc. Metals may cause allergic reactions and are known as allergens. Reaction to these metals is due to biodegradation of metals in the oral cavity. This may lead to the formation of corrosion products and their exposure to the patient. Nickel is the most common metal to cause hypersensitivity reaction. Chromium ranks second among the metals, known to trigger allergic reactions. The adverse biological reactions to these metals may include hypersensitivity, dermatitis and asthma. In addition, a significant carcinogenic and mutagenic potential has been demonstrated. The orthodontist must be familiar with the best possible alternative treatment modalities to provide the safest, most effective care possible in these cases. The present article focuses on the issue of metal hypersensitivity and its management in orthodontic

    5. Liquid metal pump

      Science.gov (United States)

      Pennell, William E.

      1982-01-01

      The liquid metal pump comprises floating seal rings and attachment of the pump diffuser to the pump bowl for isolating structural deflections from the pump shaft bearings. The seal rings also eliminate precision machining on large assemblies by eliminating the need for a close tolerance fit between the mounting surfaces of the pump and the seals. The liquid metal pump also comprises a shaft support structure that is isolated from the pump housing for better preservation of alignment of shaft bearings. The shaft support structure also allows for complete removal of pump internals for inspection and repair.

    6. Liquid metal pump

      International Nuclear Information System (INIS)

      Pennell, W.E.

      1982-01-01

      The liquid metal pump comprises floating seal rings and attachment of the pump diffuser to the pump bowl for isolating structural deflections from the pump shaft bearings. The seal rings also eliminate precision machining on large assemblies by eliminating the need for a close tolerance fit between the mounting surfaces of the pump and the seals. The liquid metal pump also comprises a shaft support structure that is isolated from the pump housing for better preservation of alignment of shaft bearings. The shaft support structure also allows for complete removal of pump internals for inspection and repair

    7. Metallic coating of microspheres

      International Nuclear Information System (INIS)

      Meyer, S.F.

      1980-01-01

      Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates

    8. Liquid metal pump

      International Nuclear Information System (INIS)

      Pennell, W.E.

      1981-01-01

      A liquid metal pump comprising a shaft support structure which is isolated from the pump housing for better preservation of alignment of shaft bearings. The shaft carries an impeller and the support structure carries an impeller cage which is slidably disposed in a diffuser so as to allow complete removal of pump internals for inspection and repair. The diffuser is concentrically supported in the pump housing which also takes up all reaction forces generated by the discharge of the liquid metal from the diffuser, with floating seals arranged between impeller cage and the diffuser. The space between the diffuser and the pump housing permits the incoming liquid to essentially surround the diffuser. (author)

    9. Superductile bulk metallic glass

      International Nuclear Information System (INIS)

      Yao, K.F.; Ruan, F.; Yang, Y.Q.; Chen, N.

      2006-01-01

      Usually, monolithic bulk metallic glasses undergo inhomogeneous plastic deformation and exhibit poor ductility (<2%) at room temperature. We report a newly developed Pd-Si binary bulk metallic glass, which exhibits a uniform plastic deformation and a large plastic engineering strain of 82% and a plastic true strain of 170%, together with initial strain hardening, slight strain softening and final strain hardening characteristics. The uniform shear deformation and the ultrahigh plasticity are mainly attributed to strain hardening, which results from the nanoscale inhomogeneity due to liquid phase separation. The formed nanoscale inhomogeneity will hinder, deflect, and bifurcate the propagation of shear bands

    10. Analysis of metal samples

      International Nuclear Information System (INIS)

      Ramirez T, J.J.; Lopez M, J.; Sandoval J, A.R.; Villasenor S, P.; Aspiazu F, J.A.

      2001-01-01

      An elemental analysis, metallographic and of phases was realized in order to determine the oxidation states of Fe contained in three metallic pieces: block, plate and cylinder of unknown material. Results are presented from the elemental analysis which was carried out in the Tandem Accelerator of ININ by Proton induced X-ray emission (PIXE). The phase analysis was carried out by X-ray diffraction which allowed to know the type of alloy or alloys formed. The combined application of nuclear techniques with metallographic techniques allows the integral characterization of industrial metals. (Author)

    11. Spinning of refractory metals

      International Nuclear Information System (INIS)

      Chang Wenkua; Zheng Han

      1989-01-01

      The effects of spinning process parameters including max. pass percentage reduction, spinning temperature, feed rate, lubricant and annealing technology on the quality of shaped components are summarized and discussed in the present paper. The above mentioned parameters are adopted in the process of spinning of barrel-shaped and specially shaped components of refractory metals and their alloys W, Mo, Nb, Zr, TZM molybdenum alloy, C-103, C-752 niobium alloy etc. The cause of leading to usual defects of spun products of refractory metals such as lamellar as 'scaling', crack, swelling, wrinkle, etc. have been analysed and the ways to eliminate the defects have been put forward. 8 figs., 5 tabs. (Author)

    12. Commodity profiles for selected metals

      International Nuclear Information System (INIS)

      Svoboda, O.; Wilson, B.M.

      1985-01-01

      This report describes the basic characteristics of 35 metals and gives the prices and production of these metals for the period 1979 to 1983/4. The description of each metal includes the ore grades and reserves, the major minerals in which the metal occurs, and the discovery, selected physical properties, sources, uses, substitutes, and effects on the environment of the metal. Graphs showing price and production cover the period 1950 to 1984, and possible future developments in these areas are forecast for each metal until the year 2000

    13. Method of dissolving metal ruthenium

      International Nuclear Information System (INIS)

      Tsuno, Masao; Soda, Yasuhiko; Kuroda, Sadaomi; Koga, Tadaaki.

      1988-01-01

      Purpose: To dissolve and clean metal ruthenium deposited to the inner surface of a dissolving vessel for spent fuel rods. Method: Metal ruthenium is dissolved in a solution of an alkali metal hydroxide to which potassium permanganate is added. As the alkali metal hydroxide used herein there can be mentioned potassium hydroxide, sodium hydroxide and lithium hydroxide can be mentioned, which is used as an aqueous solution from 5 to 20 % concentration in view of the solubility of metal ruthenium and economical merit. Further, potassium permanganate is used by adding to the solution of alkali metal hydroxide at a concentration of 1 to 5 %. (Yoshihara, H.)

    14. Heavy Metal - Exploring a magnetised metallic asteroid

      Science.gov (United States)

      Wahlund, J.-E.; Andrews, D. J.

      2017-09-01

      We propose an ESA/M5 spacecraft mission to orbit and explore (16) Psyche - the largest M-class metallic asteroid in the main belt. Recent estimates of the shape, 279×232×189 km and mass, 2.7×1019 kg of (16) Psyche make it one of the largest and densest of asteroids, 4.5 g cm-3, and together with the high surface radar reflectivity and the spectral data measured from Earth it is consistent with a bulk composition rich in iron-nickel. (16) Psyche orbits the Sun with semi-major axis 2.9 AU, 3º inclination, and is as yet unexplored in-situ.

    15. Understanding how cells allocate metals using metal sensors and metallochaperones.

      Science.gov (United States)

      Tottey, Stephen; Harvie, Duncan R; Robinson, Nigel J

      2005-10-01

      Each metalloprotein must somehow acquire the correct metal. We review the insights into metal specificity in cells provided by studies of ArsR-SmtB DNA binding, metal-responsive transcriptional repressors, and a bacterial copper chaperone. Cyanobacteria are the one bacterial group that have known enzymatic demand for cytoplasmic copper import. The copper chaperone and ATPases that supply cyanobacterial plastocyanin and cytochrome oxidase are reviewed, along with related ATPases for cobalt and zinc. These studies highlight the contributions of protein-protein interactions to metal speciation. Metal sensors and metallochaperones, along with metal transporters and metal-storage proteins, act in concert not only to supply the correct metals but also to withhold the wrong ones.

    16. Performance of metallic fuels in liquid-metal fast reactors

      International Nuclear Information System (INIS)

      Seidel, B.R.; Walters, L.C.; Kittel, J.H.

      1984-01-01

      Interest in metallic fuels for liquid-metal fast reactors has come full circle. Metallic fuels are once again a viable alternative for fast reactors because reactor outlet temperature of interest to industry are well within the range where metallic fuels have demonstrated high burnup and reliable performance. In addition, metallic fuel is very tolerant of off-normal events of its high thermal conductivity and fuel behavior. Futhermore, metallic fuels lend themselves to compact and simplified reprocessing and refabrication technologies, a key feature in a new concept for deployment of fast reactors called the Integral Fast Reactor (IFR). The IFR concept is a metallic-fueled pool reactor(s) coupled to an integral-remote reprocessing and fabrication facility. The purpose of this paper is to review recent metallic fuel performance, much of which was tested and proven during the twenty years of EBR-II operation

    17. Liquid metal level measurement

      International Nuclear Information System (INIS)

      Hale, J.C.; Leyland, K.S.

      1982-01-01

      A liquid metal level indicator is described which can be used to measure, in a stainless steel tank, the level of a nuclear reactor coolant such as sodium. The instrument, which is based on the eddy current induction effect, gives readings over substantially the full depth of the tank and indicates the sense of change of level. (U.K.)

    18. Metal cleaner poisoning

      Science.gov (United States)

      ... do so by poison control or a health care provider. If the chemical is on the skin or in the eyes, flush with lots of water for at least 15 minutes. If the person swallowed the metal cleaner, give them water or milk right away, unless a provider tells you not ...

    19. Memories in Metal

      Science.gov (United States)

      Knepper, Claire A.

      2008-01-01

      In this article, the author shares a classroom project that she introduced to her students. The project involved decorating photographs with some metal materials. The project was inspired by "The Frame," a painting by the artist Frida Kahlo. This project aims to make students think critically and connect art to their lives.

    20. Metallic glasses: structural models

      International Nuclear Information System (INIS)

      Nassif, E.

      1984-01-01

      The aim of this work is to give a summary of the attempts made up to the present in order to discribe by structural models the atomic arrangement in metallic glasses, showing also why the structure factors and atomic distribution functions cannot be always experimentally determined with a reasonable accuracy. (M.W.O.) [pt

    1. Chelation in metal intoxication

      DEFF Research Database (Denmark)

      Aaseth, Jan; Skaug, Marit Aralt; Cao, yang

      2015-01-01

      The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the incon......The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due...... to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment...... of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new...

    2. Complex metal hydrides

      DEFF Research Database (Denmark)

      Ley, Morten Brix

      2014-01-01

      og batterier de to mest lovende energibærere til mobile applikationer. Komplekse metalhydrider er blevet undersøgt i vid udstrækning over de sidste tyve år, siden de gravimetrisk og volumetrisk kan indeholde store mængder brint. Derfor er metal borhydrider velegnet til faststofopbevaring af brint...

    3. Metal forming and lubrication

      DEFF Research Database (Denmark)

      Bay, Niels

      2000-01-01

      Lubrication is essential in most metal forming processes. The lubricant film has two basic functions, [1]: i. to separate the work piece and tool surfaces and ii. to cool the workpiece and the tool. Separation of the two surfaces implies lower friction facilitating deformation and lowering the tool...

    4. Metal sorption on kaolinite

      International Nuclear Information System (INIS)

      Westrich, H.R.; Brady, P.V.; Cygan, R.T.; Nagy, K.L.; Anderson, H.L.

      1997-01-01

      A key issue in performance assessment of low-level radioactive waste sites is predicting the transport and retardation of radionuclides through local soils under a variety of hydrologic and geochemical conditions. Improved transport codes should include a mechanistic model of radionuclide retardation. The authors have been investigating metal sorption (Cs + , Sr 2+ , and Ba 2+ ) on a simple clay mineral (kaolinite) to better understand the geochemical interactions of common soil minerals with contaminated groundwaters. These studies include detailed characterizations of kaolinite surfaces, experimental adsorption measurements, surface complexation modeling, and theoretical simulations of cation sorption. The aluminol edge (010) site has been identified as the most likely site for metal sorption on kaolinite in natural solutions. Relative metal binding strengths decrease from Ba 2+ to Sr 2+ to Cs + , with some portion sorbed on both kaolinite edges and basal surfaces. Some Cs + also appears to be irreversibly sorbed on both sites. Molecular dynamics simulations suggest that Cs + is sorbed at aluminol (010) edge sites as an inner-sphere complex and weakly sorbed as an outer-sphere complex on (001) basal surfaces. These results provide the basis to understand and predict metal sorption onto kaolinite, and a framework to characterize sorption processes on more complex clay minerals

    5. Bioaccumulation of Heavy Metals

      African Journals Online (AJOL)

      komla

      acute toxicity and sublethal chronic action the devastating effects that the accumulation - including ... the laboratory and kept in holding glass (a) Copper as CuSO,.5H,0 ... from 2 psu to 21 psu) depending on time of The choice of heavy metals for this s year. ... serving as substrate and food source for Salinity of test media.

    6. Production of pure metals

      Science.gov (United States)

      Philipp, W. H.; Marsik, S. J.; May, C. E. (Inventor)

      1974-01-01

      A process for depositing elements by irradiating liquids is reported. Ultra pure elements are precipitated from aqueous solutions or suspensions of compounds. A solution of a salt of a metal to be prepared is irradiated, and the insoluble reaction product settles out. Some chemical compounds may also be prepared in this manner.

    7. Novel Ammonium Metal Borohydrides

      DEFF Research Database (Denmark)

      Grinderslev, Jakob; Jepsen, Lars Haahr; Cerny, Radovan

      Ammonium borohydride, NH4BH4, has a very high gravimetric (ρm = 24.5 wt% H2) and volumetric (157.3 g·H2/L) hydrogen content and releases 18.4 wt% H2 below 170 °C. However, NH4BH4 is metastable at RT and ambient pressure, with a half-life of ~6 h. The decomposition is strongly exothermic; therefore......, it cannot store hydrogen reversibly. Recently, the first ammonium metal borohydride, NH4Ca(BH4)3 was published, which may be considered as substitution of K+ by NH4+ in KCa(BH4)3, due to the similar sizes of NH4+ and K+[1]. This compound successfully stabilizes NH4BH4. In the present work, a series of novel...... halide-free ammonium metal borohydrides is presented, which have the chemical compositions (NH4)xM(BH4)n+x. The ammonium metal borohydrides are synthesized by cryomilling of NH4BH4 – M(BH4)n (M = Li, Na, K, Mg, Sr, Y, Mn, La, Gd) in different ratios. A new range of ammonium metal borohydrides is formed...

    8. The magic metal uranium

      International Nuclear Information System (INIS)

      1985-01-01

      ''Magic Metal'' was the first in a range of programmes for the younger secondary student. It is a very simple explanation of how a nuclear reactor works, of the basics of fission and compares nuclear with other fuels. The concepts employed were developed using classroom trials. (author)

    9. Ductile transplutonium metal alloys

      Science.gov (United States)

      Conner, William V.

      1983-01-01

      Alloys of Ce with transplutonium metals such as Am, Cm, Bk and Cf have properties making them highly suitable as sources of the transplutonium element, e.g., for use in radiation detector technology or as radiation sources. The alloys are ductile, homogeneous, easy to prepare and have a fairly high density.

    10. Flexible metal bellows

      CERN Multimedia

      CERN PhotoLab

      1975-01-01

      A set of flexible metal bellows being fatigue-tested by repeated offset motion. Such bellows assemblies were used in the SPS vacuum system at places where , for instance, beam stoppers and collimators had to be moved frequently in and out of the beam path.

    11. Metal Organic Frameworks (MOFs)

      Indian Academy of Sciences (India)

      Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 11. Molecule Matters - Metal Organic Frameworks (MOFs). R Sarvanakumar S Sankararaman. Feature Article Volume 12 Issue 11 November 2007 pp 77-86. Fulltext. Click here to view fulltext PDF. Permanent link:

    12. The Production of Uranium Metal by Metal Hydrides Incorporated

      Energy Technology Data Exchange (ETDEWEB)

      Alexander, P. P.

      1943-01-01

      Metal Hydrides Incorporated was a pioneer in the production of uranium metal on a commercial scale and supplied it to all the laboratories interested in the original research, before other methods for its production were developed. Metal Hydrides Inc. supplied the major part of the metal for the construction of the first experimental pile which, on December 2, 1942, demonstrated the feasibility of the self-sustaining chain reaction and the release of atomic energy.

    13. Direct metal laser sintering: a digitised metal casting technology.

      Science.gov (United States)

      Venkatesh, K Vijay; Nandini, V Vidyashree

      2013-12-01

      Dental technology is undergoing advancements at a fast pace and technology is being imported from various other fields. One such imported technology is direct metal laser sintering technology for casting metal crowns. This article will discuss the process of laser sintering for making metal crowns and fixed partial dentures with a understanding of their pros and cons.

    14. Immunoglobulin classes, metal binding proteins, and trace metals in ...

      African Journals Online (AJOL)

      , IgA and IgM), metal binding proteins (Transferrin, Caeruloplasmin, Alpha-2- Macroglobulin and Haptoglobin) and nutritionally essential trace metals/heavy metals (Zn, Fe, Se, Cu, Mg, Cd and Pb) in Nigerian cassava processors using single ...

    15. Direct Metal Laser Sintering: A Digitised Metal Casting Technology

      OpenAIRE

      Venkatesh, K. Vijay; Nandini, V. Vidyashree

      2013-01-01

      Dental technology is undergoing advancements at a fast pace and technology is being imported from various other fields. One such imported technology is direct metal laser sintering technology for casting metal crowns. This article will discuss the process of laser sintering for making metal crowns and fixed partial dentures with a understanding of their pros and cons.

    16. Thin films of metal-organic compounds and metal nanoparticle

      Indian Academy of Sciences (India)

      Thin films of metal-organic compounds and metal nanoparticle-embedded polymers for nonlinear optical applications. S Philip Anthony Shatabdi Porel D ... Thin films based on two very different metal-organic systems are developed and some nonlinear optical applications are explored. A family of zinc complexes which ...

    17. Purification of alkali metal nitrates

      Science.gov (United States)

      Fiorucci, Louis C.; Gregory, Kevin M.

      1985-05-14

      A process is disclosed for removing heavy metal contaminants from impure alkali metal nitrates containing them. The process comprises mixing the impure nitrates with sufficient water to form a concentrated aqueous solution of the impure nitrates, adjusting the pH of the resulting solution to within the range of between about 2 and about 7, adding sufficient reducing agent to react with heavy metal contaminants within said solution, adjusting the pH of the solution containing reducing agent to effect precipitation of heavy metal impurities and separating the solid impurities from the resulting purified aqueous solution of alkali metal nitrates. The resulting purified solution of alkali metal nitrates may be heated to evaporate water therefrom to produce purified molten alkali metal nitrate suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of alkali metal nitrates.

    18. (17) ACCUMULATION OF HEAVY METAL

      African Journals Online (AJOL)

      Adeyinka Odunsi

      Spectrophotometer (AAS) 2ID using their respective lamp and wavelengths. Calculation ... (Table 2). Concentration of heavy metals in the cassava. Lead and chromium were not significantly ..... Market basket survey for some heavy metals in ...

    19. Radioactive contamination of recycled metals

      International Nuclear Information System (INIS)

      Lubenau, J.O.; Cool, D.A.; Yusko, J.G.

      1996-01-01

      Radioactive sources commingled with metal scrap have become a major problem for the metals recycling industry worldwide. Worldwide there have been 38 confirmed reports of radioactive sources accidentally smelted with recycled metal. In some instances, contaminated metal products were subsequently distributed. The metal mills, their products and byproducts from the metal making process such as slags, crosses and dusts from furnaces can become contaminated. In the U.S., imported ferrous metal products such as reinforcement bars, pipe flanges, table legs and fencing components have been found contaminated with taco. U.S. steel mills have unintentionally smelted radioactive sources on 16 occasions. The resulting cost for decontamination waste disposal and temporary closure of the steel mill is typically USD 10,000,000 and has been as much as USD 23,000,000. Other metal recycling industries that have been affected by this problem include aluminum, copper, zinc, gold, lead and vanadium. (author)

    20. Vapor trap for liquid metal

      Energy Technology Data Exchange (ETDEWEB)

      Watanabe, T

      1968-05-22

      In a pipe system which transfers liquid metal, inert gas (cover gas) is packed above the surface of the liquid metal to prevent oxidization of the liquid. If the metal vapor is contained in such cover gas, the circulating system of the cover gas is blocked due to condensation of liquid metal inside the system. The present invention relates to an improvement in vapor trap to remove the metal vapor from the cover gas. The trap consists of a cylindrical outer body, an inlet nozzle which is deeply inserted inside the outer body and has a number of holes to inject the cove gas into the body, metal mesh or steel wool which covers the exterior of the nozzle and on which the condensation of the metal gas takes place, and a heater wire hich is wound around the nozzle to prevent condensation of the metal vapor at the inner peripheral side of the mesh.

    1. Powder metallurgy of refractory metals

      International Nuclear Information System (INIS)

      Eck, R.

      1979-01-01

      This paper reports on the powder metallurgical methods for the production of high-melting materials, such as pure metals and their alloys, compound materials with a tungsten base and hard metals from liquid phase sintered carbides. (author)

    2. Transition metals in carbohydrate chemistry

      DEFF Research Database (Denmark)

      Madsen, Robert

      1997-01-01

      This review describes the application of transition metal mediated reactions in carbohydrate synthesis. The different metal mediated transformations are divided into reaction types and illustrated by various examples on monosaccharide derivatives. Carbon-carbon bond forming reactions are further ...

    3. Extraterrestrial Metals Processing, Phase II

      Data.gov (United States)

      National Aeronautics and Space Administration — The Extraterrestrial Metals Processing (EMP) system produces iron, silicon, and light metals from Mars, Moon, or asteroid resources in support of advanced human...

    4. Metal semiconductor contacts and devices

      CERN Document Server

      Cohen, Simon S; Einspruch, Norman G

      1986-01-01

      VLSI Electronics Microstructure Science, Volume 13: Metal-Semiconductor Contacts and Devices presents the physics, technology, and applications of metal-semiconductor barriers in digital integrated circuits. The emphasis is placed on the interplay among the theory, processing, and characterization techniques in the development of practical metal-semiconductor contacts and devices.This volume contains chapters that are devoted to the discussion of the physics of metal-semiconductor interfaces and its basic phenomena; fabrication procedures; and interface characterization techniques, particularl

    5. Electroless metal plating of plastics

      Science.gov (United States)

      Krause, L.J.

      1982-09-20

      Process for plating main group metals on aromatic polymers is carried out by the use of a nonaqueous solution of a salt of an alkali metal in a positive valence state and a main group metal in a negative valence state with contact between the solution and polymer providing a redox reaction causing the deposition of the main group metal and the reduction of the polymer. Products from the process exhibit useful decorative and electrical properties.

    6. Upgrading platform using alkali metals

      Science.gov (United States)

      Gordon, John Howard

      2014-09-09

      A process for removing sulfur, nitrogen or metals from an oil feedstock (such as heavy oil, bitumen, shale oil, etc.) The method involves reacting the oil feedstock with an alkali metal and a radical capping substance. The alkali metal reacts with the metal, sulfur or nitrogen content to form one or more inorganic products and the radical capping substance reacts with the carbon and hydrogen content to form a hydrocarbon phase. The inorganic products may then be separated out from the hydrocarbon phase.

    7. Methods of recovering alkali metals

      Science.gov (United States)

      Krumhansl, James L; Rigali, Mark J

      2014-03-04

      Approaches for alkali metal extraction, sequestration and recovery are described. For example, a method of recovering alkali metals includes providing a CST or CST-like (e.g., small pore zeolite) material. The alkali metal species is scavenged from the liquid mixture by the CST or CST-like material. The alkali metal species is extracted from the CST or CST-like material.

    8. Electrical Conductivity in Transition Metals

      Science.gov (United States)

      Talbot, Christopher; Vickneson, Kishanda

      2013-01-01

      The aim of this "Science Note" is to describe how to test the electron-sea model to determine whether it accurately predicts relative electrical conductivity for first-row transition metals. In the electron-sea model, a metal crystal is viewed as a three-dimensional array of metal cations immersed in a sea of delocalised valence…

    9. METHOD OF PURIFYING URANIUM METAL

      Science.gov (United States)

      Blanco, R.E.; Morrison, B.H.

      1958-12-23

      The removal of lmpurities from uranlum metal can be done by a process conslstlng of contacting the metal with liquid mercury at 300 icient laborato C, separating the impunitycontalnlng slag formed, cooling the slag-free liquld substantlally below the point at which uranlum mercurlde sollds form, removlng the mercury from the solids, and recovering metallic uranium by heating the solids.

    10. Bacterial metal resistance genes and metal bioavailability in contaminated sediments

      International Nuclear Information System (INIS)

      Roosa, Stéphanie; Wattiez, Ruddy; Prygiel, Emilie; Lesven, Ludovic; Billon, Gabriel; Gillan, David C.

      2014-01-01

      In bacteria a metal may be defined as bioavailable if it crosses the cytoplasmic membrane to reach the cytoplasm. Once inside the cell, specific metal resistance systems may be triggered. In this research, specific metal resistance genes were used to estimate metal bioavailability in sediment microbial communities. Gene levels were measured by quantitative PCR and correlated to metals in sediments using five different protocols to estimate dissolved, particle-adsorbed and occluded metals. The best correlations were obtained with czcA (a Cd/Zn/Co efflux pump) and Cd/Zn adsorbed or occluded in particles. Only adsorbed Co was correlated to czcA levels. We concluded that the measurement of czcA gene levels by quantitative PCR is a promising tool which may complement the classical approaches used to estimate Cd/Zn/Co bioavailability in sediment compartments. - Highlights: • Metal resistance genes were used to estimate metal bioavailability in sediments. • Gene levels were correlated to metals using 5 different metal extraction protocols. • CzcA gene levels determined by quantitative PCR is a promising tool for Cd/Zn/Co. - Capsule Bacterial czcA is a potential biomarker of Cd, Zn and Co bioavailability in aquatic sediments as shown by quantitative PCR and sequential metal extraction

    11. Plant responses to metal toxicity

      Energy Technology Data Exchange (ETDEWEB)

      Briat, J.F. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie moleculaire des plantes, CNRS, URA 2133; Lebrun, M. [Montpellier-2 Univ., 34 (France). Biochimie et physiologie vegetale appliquee

      1999-01-01

      Increased metal concentration in the soils, up to toxic levels, is becoming an important environmental problem. Safety rule evolution will require solutions in order to cope with food safety rules, and to freeze metal leakage from heavily metal-poisoned soils, such as those from industrial fallows. In this context, plants could serve to develop bio-assays in order to promote new standards, more realistic than the mass of a given metal per kg of soil, that does not consider the metal bio-disponibility. Plants could also be used for phyto-extraction and/or phyto-stabilization. To reach these objectives, a genetic approach could be useful to generate metal-tolerant plants with enough biomass. In this work is more particularly studied the plant responses to metal toxicity. Metal toxicity for living organisms involves oxidative and /or genotoxic mechanisms. Plant protection against metal toxicity occurs, at least in part, through control of root metal uptake and of long distance metal transport. Inside cells, proteins such as ferritins and metallothioneins, and glutathione-derived peptides named phyto-chelatins, participate in excess metal storage and detoxification. Low molecular weight organic molecules, mainly organic acids and amino acids and their derivatives, also play an important role in plant metal homeostasis. When these systems are overloaded, oxidative stress defense mechanisms are activated. Molecular and cellular knowledge of these processes will be necessary to improve plant metal resistance. Occurrence of naturally tolerant plants which hyper accumulate metals provides helpful tools for this research. (authors) 130 refs.

    12. Liquid metal magnetohydrodynamic convertor

      International Nuclear Information System (INIS)

      Aladiev, I.T.; Dzhamardzhashvili, V.A.

      1981-01-01

      This invention relates to the generation of electrical energy by direct conversion from thermal or electrical energy and notably to liquid metal magnetohydrodynamic convertors. The convertor described in this invention can be successfully used as a source of electrical energy for space vessels, for underwater vessels, for aeronautics and for the generation of electrical energy in thermal or atomic power plants. This liquid metal convertor consists of a heat source, a two phase nozzle, a separator, a steam diffuser and a condenser. These elements are connected together hydraulically in series. The condenser is connected hydraulically to a heat source, a liquid diffuser and a magnetohydrodynamic generator. These elements are interconnected hydraulically to the separator and heat source [fr

    13. Superconductivity in transition metals.

      Science.gov (United States)

      Slocombe, Daniel R; Kuznetsov, Vladimir L; Grochala, Wojciech; Williams, Robert J P; Edwards, Peter P

      2015-03-13

      A qualitative account of the occurrence and magnitude of superconductivity in the transition metals is presented, with a primary emphasis on elements of the first row. Correlations of the important parameters of the Bardeen-Cooper-Schrieffer theory of superconductivity are highlighted with respect to the number of d-shell electrons per atom of the transition elements. The relation between the systematics of superconductivity in the transition metals and the periodic table high-lights the importance of short-range or chemical bonding on the remarkable natural phenomenon of superconductivity in the chemical elements. A relationship between superconductivity and lattice instability appears naturally as a balance and competition between localized covalent bonding and so-called broken covalency, which favours d-electron delocalization and superconductivity. In this manner, the systematics of superconductivity and various other physical properties of the transition elements are related and unified. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

    14. Metallic spintronic devices

      CERN Document Server

      Wang, Xiaobin

      2014-01-01

      Metallic Spintronic Devices provides a balanced view of the present state of the art of metallic spintronic devices, addressing both mainstream and emerging applications from magnetic tunneling junction sensors and spin torque oscillators to spin torque memory and logic. Featuring contributions from well-known and respected industrial and academic experts, this cutting-edge work not only presents the latest research and developments but also: Describes spintronic applications in current and future magnetic recording devicesDiscusses spin-transfer torque magnetoresistive random-access memory (STT-MRAM) device architectures and modelingExplores prospects of STT-MRAM scaling, such as detailed multilevel cell structure analysisInvestigates spintronic device write and read optimization in light of spintronic memristive effectsConsiders spintronic research directions based on yttrium iron garnet thin films, including spin pumping, magnetic proximity, spin hall, and spin Seebeck effectsProposes unique solutions for ...

    15. Antibacterial Metallic Touch Surfaces

      Directory of Open Access Journals (Sweden)

      Victor M. Villapún

      2016-08-01

      Full Text Available Our aim is to present a comprehensive review of the development of modern antibacterial metallic materials as touch surfaces in healthcare settings. Initially we compare Japanese, European and US standards for the assessment of antimicrobial activity. The variations in methodologies defined in these standards are highlighted. Our review will also cover the most relevant factors that define the antimicrobial performance of metals, namely, the effect of humidity, material geometry, chemistry, physical properties and oxidation of the material. The state of the art in contact-killing materials will be described. Finally, the effect of cleaning products, including disinfectants, on the antimicrobial performance, either by direct contact or by altering the touch surface chemistry on which the microbes attach, will be discussed. We offer our outlook, identifying research areas that require further development and an overview of potential future directions of this exciting field.

    16. Method of producing homogeneous mixed metal oxides and metal-metal oxide mixtures

      International Nuclear Information System (INIS)

      1980-01-01

      Finely divided powders are prepared by first reacting an aqueous solution containing dissolved metal values with excess urea. After the reaction of water in the solution with urea is complete, the resulting molten urea solution is heated to cause metal values in solution to precipitate. The resulting mixture containing precipitated metal values is heated to evaporate volatile material, leaving a dry powder containing the metal values. Detailed examples are given. (U.K.)

    17. Understanding metals pollutions

      International Nuclear Information System (INIS)

      Bril, H.; Bollinger, J.C.

      2006-01-01

      Either from natural or anthropic origin, be it normal or accidental (Tchernobyl), metallic elements are found everywhere in our environment. After a presentation of their repartition and mobility in water, sediments or soils, the mechanisms allowing their dispersion or their concentration are shown. Finally, transfers between environmental compartments are presented, before evoking the case of polluted sites: diagnostic, remediation and long-time management. (authors)

    18. Submicrometer Metallic Barcodes

      Science.gov (United States)

      Nicewarner-Peña, Sheila R.; Freeman, R. Griffith; Reiss, Brian D.; He, Lin; Peña, David J.; Walton, Ian D.; Cromer, Remy; Keating, Christine D.; Natan, Michael J.

      2001-10-01

      We synthesized multimetal microrods intrinsically encoded with submicrometer stripes. Complex striping patterns are readily prepared by sequential electrochemical deposition of metal ions into templates with uniformly sized pores. The differential reflectivity of adjacent stripes enables identification of the striping patterns by conventional light microscopy. This readout mechanism does not interfere with the use of fluorescence for detection of analytes bound to particles by affinity capture, as demonstrated by DNA and protein bioassays.

    19. PRODUCTION OF ACTINIDE METAL

      Science.gov (United States)

      Knighton, J.B.

      1963-11-01

      A process of reducing actinide oxide to the metal with magnesium-zinc alloy in a flux of 5 mole% of magnesium fluoride and 95 mole% of magnesium chloride plus lithium, sodium, potassium, calcium, strontium, or barium chloride is presented. The flux contains at least 14 mole% of magnesium cation at 600-- 900 deg C in air. The formed magnesium-zinc-actinide alloy is separated from the magnesium-oxide-containing flux. (AEC)

    20. Therapy of metal poisoning

      International Nuclear Information System (INIS)

      Lindenbaum, A.

      1975-01-01

      The following studies were conducted: physical character of lead acetate and other toxic metal compounds as related to tissue distribution, toxicity, and therapeutic removal; interactions of monomeric plutonium with specific components of mouse liver and skeleton; metabolism and therapeutic decorporation of plutonium in mice and dogs; comparative studies of tissue distribution of plutonium isotopes; and microdistribution of monomeric and polymeric plutonium in beagle liver and bone

    1. Ultralight metallic microlattices.

      Science.gov (United States)

      Schaedler, T A; Jacobsen, A J; Torrents, A; Sorensen, A E; Lian, J; Greer, J R; Valdevit, L; Carter, W B

      2011-11-18

      Ultralight (nickel plating, and subsequently etching away the template. The resulting metallic microlattices exhibit densities ρ ≥ 0.9 milligram per cubic centimeter, complete recovery after compression exceeding 50% strain, and energy absorption similar to elastomers. Young's modulus E scales with density as E ~ ρ(2), in contrast to the E ~ ρ(3) scaling observed for ultralight aerogels and carbon nanotube foams with stochastic architecture. We attribute these properties to structural hierarchy at the nanometer, micrometer, and millimeter scales.

    2. Heavy metals in our foodstuffs

      Energy Technology Data Exchange (ETDEWEB)

      1983-11-01

      The special group ''chemistry of food and forensic chemistry'' of the Association of German Analytical Chemists in Munich in 1983 issued a statement on that subject. The publication points out how heavy metals (examples: lead, cadmium and mercury) make their way into the foodstuffs, how many heavy metals are contained in our foodstuffs, which heavy metals are indispensable minerals and which aren't, and which heavy metals are ingested with food. It concludes by discussing how heavy metal contamination of our food can be prevented.

    3. Metallicity in the GC

      International Nuclear Information System (INIS)

      Najarro, Francisco

      2006-01-01

      We review quantitative spectroscopic studies of massive stars in the three Galactic Center clusters: Quintuplet, Arches and Central cluster. Thanks to the impressive evolution of IR detectors and the new generation of line blanketed models for the extended atmospheres of hot stars we are able to accurately derive the physical properties and metallicity estimates of the massive stars in these clusters. For the Quintuplet cluster our analysis of the LBVs provides a direct estimate of a-elements and Fe chemical abundances in these objects. For the Arches cluster, we introduce a method based on the N abundance of WNL stars and the theory of evolution of massive stars. For the Central cluster, new observations reveal IRS 8 as an outsider with respect to the rest of massive stars in the cluster both in terms of age and location. Using the derived properties of IR.S 8, a new method is presented to derive metallicity from the OIII feature at 2.115 μm. Our results indicate solar metallicity in the three clusters

    4. European Metals Conference

      CERN Document Server

      Vereecken, Jean

      1991-01-01

      This volume contains the papers that will be presented at 'EMC '91 '-the European Metals Conference-to be held in Brussels, Belgium, from 15 to 20 September 1991, and organized by Benelux Metallurgie, GDMB (Gesellschaft Deutscher Metallhutten­ und Bergleute) and IMM (the Institution of Mining and Metallurgy). 'EMC '91' is the first of an intended major series organized at the European level with the aim of bringing together all those who are involved with the extraction and processing of non-ferrous metals-European metallurgists and their international colleagues-to provide them with the opportunity to exchange views on the state and evolution of their industry. The programme covers all the different aspects of the metallurgy of non-ferrous metals from mining to fabricated products. Particular attention is being paid to the European non -ferrous industry with respect to changes in demand, the technology used, pressures on the environment and the competitive position of manufacturers. The contributions of the...

    5. PREFACE: Half Metallic Ferromagnets

      Science.gov (United States)

      Dowben, Peter

      2007-08-01

      Since its introduction by de Groot and colleagues in the early 1980s [1], the concept of half metallic ferromagnetism has attracted great interest. Idealized, half-metals have only one spin channel for conduction: the spin-polarized band structure exhibits metallic behavior for one spin channel, while the other spin band structure exhibits a gap at the Fermi level. Due to the gap for one spin direction, the density of states at the Fermi level has, theoretically, 100 & spin polarization. This gap in the density of states in one spin at the Fermi level, for example ↓ so N↓ (EF) = 0, also causes the resistance of that channel to go to infinity. At zero or low temperatures, the nonquasiparticle density of states (electron correlation effects), magnons and spin disorder reduce the polarization from the idealized 100 & polarization. At higher temperatures magnon-phonon coupling and irreversible compositional changes affect polarization further. Strategies for assessing and reducing the effects of finite temperatures on the polarization are now gaining attention. The controversies surrounding the polarization stability of half metallic ferromagnets are not, however, limited to the consideration of finite temperature effects alone. While many novel half metallic materials have been predicted, materials fabrication can be challenging. Defects, surface and interface segregation, and structural stability can lead to profound decreases in polarization, but can also suppress long period magnons. There is a 'delicate balance of energies required to obtain half metallic behaviour: to avoid spin flip scattering, tiny adjustments in atomic positions might occur so that a gap opens up in the other spin channel' [2]. When considering 'spintronics' devices, a common alibi for the study of half metallic systems, surfaces and interfaces become important. Free enthalpy differences between the surface and the bulk will lead to spin minority surface and interface states, as well as

    6. Metallic fuel development

      International Nuclear Information System (INIS)

      Walters, L.C.

      1987-01-01

      Metallic fuels are capable of achieving high burnup as a result of design modifications instituted in the late 1960's. The gap between the fuel slug and the cladding is fixed such that by the time the fuel swells to the cladding the fission gas bubbles interconnect and release the fission gas to an appropriately sized plenum volume. Interconnected porosity thus provides room for the fuel to deform from further swelling rather than stress the cladding. In addition, the interconnected porosity allows the fuel pin to be tolerant to transient events because as stresses are generated during a transient event the fuel flows rather than applying significant stress to the cladding. Until 1969 a number of metallic fuel alloys were under development in the US. At that time the metallic fuel development program in the US was discontinued in favor of ceramic fuels. However, development had proceeded to the point where it was clear that the zirconium addition to uranium-plutonium fuel would yield a ternary fuel with an adequately high solidus temperature and good compatibility with austenitic stainless steel cladding. Furthermore, several U-Pu-Zr fuel pins had achieved about 6 at.% bu by the late 1960's, without failure, and thus the prospect for high burnup was promising

    7. Electron energies in metals

      International Nuclear Information System (INIS)

      Mahan, G.D.; Tennessee Univ., Knoxville, TN

      1991-01-01

      The modern era of electron-electron interactions began a decade ago. Plummer's group initiated a program of using angular resolved photoemission to examine the band structure of the simple metals. Beginning with aluminum, and carrying on to sodium and potassium, they always found that the occupied energy bands were much narrower than expected. For example, the compressed energy bands for metallic potassium suggest a band effective mass of m* = 1.33m e . This should be compared to the band mass found from optical conductivity m*/m e = 1.01 ± 0.01. The discrepancy between these results is startling. It was this great difference which started my group doing calculations. Our program was two-fold. On one hand, we reanalyzed the experimental data, in order to see if Plummer's result was an experimental artifact. On the other hand, we completely redid the electron-electron self-energy calculations for simple metals, using the most modern choices of local-field corrections and vertex corrections. Our results will be reported in these lectures. They can be summarized as following: Our calculations give the same effective masses as the older calculations, so the theory is relatively unchanged; Our analysis of the experiments suggests that the recent measurements of band narrowing are an experimental artifact. 38 refs., 9 figs

    8. Lanthanide metal-organic frameworks

      International Nuclear Information System (INIS)

      Cheng, Peng

      2015-01-01

      This book contains the following nine chapters: lanthanide metal-organic frameworks: syntheses, properties, and potential applications (Stephen Fordham, Xuan Wang, Mathieu Bosch, Hong-Cai Zhou); 2. chiral lanthanide metal-organic frameworks (Weisheng Liu, Xiaoliang Tang); 3. Porous lanthanide metal-organic frameworks for gas storage and separation (Bin Li, Banglin Chen); 4. Luminescent lanthanide metal-organic frameworks (Xue-Zhi Song, Shu-Yan Song, Hong-Jie Zhang); 5. Metal-organic frameworks based on lanthanide clusters (Lian Chen, Feilong Jiang, Kang Zhou, Mingyan Wu, Maochun Hong); 6. metal-organic frameworks with d-f cyanide bridges: structural diversity, bonding regime, and magnetism (Marilena Ferbinteanu, Fanica Cimpoesu, Stefania Tanase); 7. transition-lanthanide heterometal-organic frameworks: synthesis, structures, and properties (Wei Shi, Ke Liu, Peng Cheng); 8: MOFs of uranium and the actinides (Juan Su, Jiesheng Chen); 9. Nanostructured and/or nanoscale lanthanide metal-organic frameworks (Zhonghao Zhang, Zhiping Zheng).

    9. Carbothermic reduction of refractory metals

      International Nuclear Information System (INIS)

      Anderson, R.N.; Parlee, N.A.D.

      1976-01-01

      The reduction of stable refractory metal oxides by carbon is generally unacceptable since the product is usually contaminated with carbides. The carbide formation may be avoided by selecting a solvent metal to dissolve the reactive metal as it is produced and reduce its chemical activity below that required for carbide formation. This approach has been successfully applied to the oxides of Si, Zr, Ti, Al, Mg, and U. In the case where a volatile suboxide, a carbonyl reaction, or a volatile metal occur, the use of the solvent metal appears satisfactory to limit the loss of material at low pressures. In several solute--solvent systems, vacuum evaporation is used to strip the solvent metal from the alloy to give the pure metal

    10. Bulk metallic glass matrix composites

      International Nuclear Information System (INIS)

      Choi-Yim, H.; Johnson, W.L.

      1997-01-01

      Composites with a bulk metallic glass matrix were synthesized and characterized. This was made possible by the recent development of bulk metallic glasses that exhibit high resistance to crystallization in the undercooled liquid state. In this letter, experimental methods for processing metallic glass composites are introduced. Three different bulk metallic glass forming alloys were used as the matrix materials. Both ceramics and metals were introduced as reinforcement into the metallic glass. The metallic glass matrix remained amorphous after adding up to a 30 vol% fraction of particles or short wires. X-ray diffraction patterns of the composites show only peaks from the second phase particles superimposed on the broad diffuse maxima from the amorphous phase. Optical micrographs reveal uniformly distributed particles in the matrix. The glass transition of the amorphous matrix and the crystallization behavior of the composites were studied by calorimetric methods. copyright 1997 American Institute of Physics

    11. Lanthanide metal-organic frameworks

      Energy Technology Data Exchange (ETDEWEB)

      Cheng, Peng (ed.) [Nankai Univ., Tianjin (China). Dept. of Chemistry

      2015-03-01

      This book contains the following nine chapters: lanthanide metal-organic frameworks: syntheses, properties, and potential applications (Stephen Fordham, Xuan Wang, Mathieu Bosch, Hong-Cai Zhou); 2. chiral lanthanide metal-organic frameworks (Weisheng Liu, Xiaoliang Tang); 3. Porous lanthanide metal-organic frameworks for gas storage and separation (Bin Li, Banglin Chen); 4. Luminescent lanthanide metal-organic frameworks (Xue-Zhi Song, Shu-Yan Song, Hong-Jie Zhang); 5. Metal-organic frameworks based on lanthanide clusters (Lian Chen, Feilong Jiang, Kang Zhou, Mingyan Wu, Maochun Hong); 6. metal-organic frameworks with d-f cyanide bridges: structural diversity, bonding regime, and magnetism (Marilena Ferbinteanu, Fanica Cimpoesu, Stefania Tanase); 7. transition-lanthanide heterometal-organic frameworks: synthesis, structures, and properties (Wei Shi, Ke Liu, Peng Cheng); 8: MOFs of uranium and the actinides (Juan Su, Jiesheng Chen); 9. Nanostructured and/or nanoscale lanthanide metal-organic frameworks (Zhonghao Zhang, Zhiping Zheng).

    12. Utility industry evaluation of the metal fuel facility and metal fuel performance for liquid metal reactors

      International Nuclear Information System (INIS)

      Burstein, S.; Gibbons, J.P.; High, M.D.; O'Boyle, D.R.; Pickens, T.A.; Pilmer, D.F.; Tomonto, J.R.; Weinberg, C.J.

      1990-02-01

      A team of utility industry representatives evaluated the liquid metal reactor metal fuel process and facility conceptual design being developed by Argonne National Laboratory (ANL) under Department of Energy sponsorship. The utility team concluded that a highly competent ANL team was making impressive progress in developing high performance advanced metal fuel and an economic processing and fabrication technology. The utility team concluded that the potential benefits of advanced metal fuel justified the development program, but that, at this early stage, there are considerable uncertainties in predicting the net overall economic benefit of metal fuel. Specific comments and recommendations are provided as a contribution towards enhancing the development program. 6 refs

    13. Alkali metal and alkali metal hydroxide intercalates of the layered transition metal disulfides

      International Nuclear Information System (INIS)

      Kanzaki, Y.; Konuma, M.; Matsumoto, O.

      1981-01-01

      The intercalation reaction of some layered transition metal disulfides with alkali metals, alkali metal hydroxides, and tetraalkylammonium hydroxides were investigated. The alkali metal intercalates were prepared in the respective metal-hexamethylphosphoric triamide solutions in vaccuo, and the hydroxide intercalates in aqueous hydroxide solutions. According to the intercalation reaction, the c-lattice parameter was increased, and the increase indicated the expansion of the interlayer distance. In the case of alkali metal intercalates, the expansion of the interlayer distance increased continuously, corresponding to the atomic radius of the alkali metal. On the other hand, the hydroxide intercalates showed discrete expansion corresponding to the effective ionic radius of the intercalated cation. All intercalates of TaS 2 amd NbS 2 were superconductors. The expansion of the interlayer distance tended to increase the superconducting transition temperature in the intercalates of TaS 2 and vice versa in those of NbS 2 . (orig.)

    14. The tribology of metal-on-metal total hip replacements.

      Science.gov (United States)

      Scholes, S C; Unsworth, A

      2006-02-01

      Total hip surgery is an effective way of alleviating the pain and discomfort caused by diseased or damaged joints. However, in the majority of cases, these joints have a finite life. The main reason for failure is osteolysis (bone resorption). It is well documented that an important cause of osteolysis, and therefore the subsequent loosening and failure of conventional metal- or ceramic-on-ultra-high molecular weight polyethylene joints, is the body's immunological response to the polyethylene wear particles. To avoid this, interest has been renewed in metal-on-metal joints. The intention of this paper is to review the studies that have taken place within different laboratories to determine the tribological performance of new-generation metal-on-metal total hip replacements. These types of joint offer a potential solution to enhance the longevity of prosthetic hip systems; however, problems may arise owing to the effects of metal ion release, which are, as yet, not fully understood.

    15. Alkali metal-refractory metal biphase electrode for AMTEC

      Science.gov (United States)

      Williams, Roger M. (Inventor); Bankston, Clyde P. (Inventor); Cole, Terry (Inventor); Khanna, Satish K. (Inventor); Jeffries-Nakamura, Barbara (Inventor); Wheeler, Bob L. (Inventor)

      1989-01-01

      An electrode having increased output with slower degradation is formed of a film applied to a beta-alumina solid electrolyte (BASE). The film comprises a refractory first metal M.sup.1 such as a platinum group metal, suitably platinum or rhodium, capable of forming a liquid or a strong surface adsorption phase with sodium at the operating temperature of an alkali metal thermoelectric converter (AMTEC) and a second refractory metal insoluble in sodium or the NaM.sup.1 liquid phase such as a Group IVB, VB or VIB metal, suitably tungsten, molybdenum, tantalum or niobium. The liquid phase or surface film provides fast transport through the electrode while the insoluble refractory metal provides a structural matrix for the electrode during operation. A trilayer structure that is stable and not subject to deadhesion comprises a first, thin layer of tungsten, an intermediate co-deposited layer of tungsten-platinum and a thin surface layer of platinum.

    16. Economic aspects of metals recover

      Science.gov (United States)

      Wieczorek, Daria; Kwaśniewska, Dobrawa

      2018-03-01

      One of the modern economy models is circular economy in which wastes should be considered as resource and used in an efficient and sustainable way. This also concerns to metals included in scraps. However, the need for metal recovery from waste is not only the result of the latest economic trends but also the result of large and constantly changing demand for metals. Shrinking natural sources of metals, concentrations of ores in small number of countries in the world and resulting from this dependence on import, geopolitical situation, new technologies demands are only a few most important determinants that have been changing the structure of the metal market over years. In this chapter, authors focused on the presentation of economic aspects of metal recovery from various sources. The chapter presents the characteristic of metal market elements (supply, demand and price) and changes that took place over decades, underlining the structure of precious and highly desirable metal market elements. Balance between the demand and supply ensures price stability and rationalizes inflation. However, growing demand on many means that secure supply chains, such as recycling and material recovery, are essential to ensure continuity in the supply chain and guarantee unrestricted technological progress and innovation. The data included in this chapter presents also the concentration of different metals and group of metals in wastes pointing that recycling of waste can become one of the possibilities of acquiring missing and critical metals. Metal-laden wastes include a few groups: waste electrical and electronic equipments, catalysts of different application, introduced on chemical, petrochemical or automotive market, galvanic wastes and wastewaters. The profitability assessment of recycling processes is very complicated. Nevertheless cited data shows that profitability of recovery depends on the metal analyzed and the type of waste. It must be underline that an optimized

    17. Chromium metal organic frameworks and synthesis of metal organic frameworks

      Science.gov (United States)

      Zhou, Hong-Cai; Liu, Tian-Fu; Lian, Xizhen; Zou, Lanfang; Feng, Dawei

      2018-04-24

      The present invention relates to monocrystalline metal organic frameworks comprising chromium ions and carboxylate ligands and the use of the same, for example their use for storing a gas. The invention also relates to methods for preparing metal organic frameworks comprising chromium, titanium or iron ions and carboxylate ligands. The methods of the invention allow such metal organic frameworks to be prepared in monocrystalline or polycrystalline forms.

    18. Metallic nanosystems in catalysis

      International Nuclear Information System (INIS)

      Bukhtiyarov, Valerii I; Slin'ko, Mikhail G

      2001-01-01

      The reactivities of metallic nanosystems in catalytic processes are considered. The activities of nanoparticles in catalysis are due to their unique microstructures, electronic properties and high specific surfaces of the active centres. The problems of increasing the selectivities of catalytic processes are discussed using several nanosystems as examples. The mutual effects of components of bimetallic nanoparticles are discussed. The prospects for theoretical and experimental investigations into catalytic nanosystems and the construction of industrial catalysts based on them are evaluated. The bibliography includes 207 references.

    19. Metallic fuel design development

      Energy Technology Data Exchange (ETDEWEB)

      Hwang, Woan; Kang, H. Y.; Lee, B. O. and others

      1999-04-01

      This report describes the R and D results of the ''Metallic Fuel Design Development'' project that performed as a part of 'Nuclear Research and Development Program' during the '97 - '98 project years. The objectives of this project are to perform the analysis of thermo-mechanical and irradiation behaviors, and preliminary conceptual design for the fuel system of the KALIMER liquid metal reactor. The following are the major results that obtained through the project. The preliminary design requirements and design criteria which are necessary in conceptual design stage, are set up. In the field of fuel pin design, the pin behavior analysis, failure probability prediction, and sensitivity analysis are performed under the operation conditions of steady-state and transient accidents. In the area of assembly duct analysis; 1) KAFACON-2D program is developed to calculate an array configuration of inner shape of assembly duct, 2) Stress-strain analysis are performed for the components of assembly such as, handling socket, mounting rail and wire wrap, 3) The BDI program is developed to analyze mechanical interaction between pin bundle and duct, 4) a vibration analysis is performed to understand flow-induced vibration of assembly duct, 5) The NUBOW-2D, which is bowing and deformation analysis code for assembly duct, is modified to be operated in KALIMER circumstance, and integrity evaluation of KALIMER core assembly is carried out using the modified NUBOW-2D and the CRAMP code in U.K., and 6) The KALIMER assembly duct is manufactured to be used in flow test. In the area of non-fuel assembly, such as control, reflector, shielding, GEM and USS, the states-of-the-arts and the major considerations in designing are evaluated, and the design concepts are derived. The preliminary design description and their design drawing of KALIMER fuel system are prepared based upon the above mentioned evaluation and analysis. The achievement of conceptual

    20. Metallic fuel design development

      International Nuclear Information System (INIS)

      Hwang, Woan; Kang, H. Y.; Lee, B. O. and others

      1999-04-01

      This report describes the R and D results of the ''Metallic Fuel Design Development'' project that performed as a part of 'Nuclear Research and Development Program' during the '97 - '98 project years. The objectives of this project are to perform the analysis of thermo-mechanical and irradiation behaviors, and preliminary conceptual design for the fuel system of the KALIMER liquid metal reactor. The following are the major results that obtained through the project. The preliminary design requirements and design criteria which are necessary in conceptual design stage, are set up. In the field of fuel pin design, the pin behavior analysis, failure probability prediction, and sensitivity analysis are performed under the operation conditions of steady-state and transient accidents. In the area of assembly duct analysis; 1) KAFACON-2D program is developed to calculate an array configuration of inner shape of assembly duct, 2) Stress-strain analysis are performed for the components of assembly such as, handling socket, mounting rail and wire wrap, 3) The BDI program is developed to analyze mechanical interaction between pin bundle and duct, 4) a vibration analysis is performed to understand flow-induced vibration of assembly duct, 5) The NUBOW-2D, which is bowing and deformation analysis code for assembly duct, is modified to be operated in KALIMER circumstance, and integrity evaluation of KALIMER core assembly is carried out using the modified NUBOW-2D and the CRAMP code in U.K., and 6) The KALIMER assembly duct is manufactured to be used in flow test. In the area of non-fuel assembly, such as control, reflector, shielding, GEM and USS, the states-of-the-arts and the major considerations in designing are evaluated, and the design concepts are derived. The preliminary design description and their design drawing of KALIMER fuel system are prepared based upon the above mentioned evaluation and analysis. The achievement of conceptual design technology on metallic fuel

    1. Speciation in Metal Toxicity and Metal-Based Therapeutics

      Directory of Open Access Journals (Sweden)

      Douglas M. Templeton

      2015-04-01

      Full Text Available Metallic elements, ions and compounds produce varying degrees of toxicity in organisms with which they come into contact. Metal speciation is critical to understanding these adverse effects; the adjectives “heavy” and “toxic” are not helpful in describing the biological properties of individual elements, but detailed chemical structures are. As a broad generalization, the metallic form of an element is inert, and the ionic salts are the species that show more significant bioavailability. Yet the salts and other chelates of a metal ion can give rise to quite different toxicities, as exemplified by a range of carcinogenic potential for various nickel species. Another important distinction comes when a metallic element is organified, increasing its lipophilicity and hence its ability to penetrate the blood brain barrier, as is seen, for example, with organic mercury and tin species. Some metallic elements, such as gold and platinum, are themselves useful therapeutic agents in some forms, while other species of the same element can be toxic, thus focusing attention on species interconversions in evaluating metal-based drugs. The therapeutic use of metal-chelating agents introduces new species of the target metal in vivo, and this can affect not only its desired detoxification, but also introduce a potential for further mechanisms of toxicity. Examples of therapeutic iron chelator species are discussed in this context, as well as the more recent aspects of development of chelation therapy for uranium exposure.

    2. PREPARATION OF METAL OXIDE POWDERS FROM METAL LOADED VERSATIC ACID

      OpenAIRE

      KAKIHATA, Takayuki; USAMI, Kensuke; YAMAMOTO, Hideki; SHIBATA, Junji

      1998-01-01

      A production process for metal oxide powders was developed using a solvent extraction method. Versatic Acid 10 and D2EHPA solutions containing copper, zinc and nickel were used for a precipitation-stripping process, where oxalic acid was added to the solution as a precipitation reagent.Copper, zinc and nickel oxalates were easily formed in an aqueous phase, and 99.9% of precipitation was obtained for each metal during this process. These metal oxalates were easily converted to metal oxides by...

    3. Advances in metal forming expert system for metal forming

      CERN Document Server

      Hingole, Rahulkumar Shivajirao

      2015-01-01

      This comprehensive book offers a clear account of the theory and applications of advanced metal forming. It provides a detailed discussion of specific forming processes, such as deep drawing, rolling, bending extrusion and stamping. The author highlights recent developments of metal forming technologies and explains sound, new and powerful expert system techniques for solving advanced engineering problems in metal forming. In addition, the basics of expert systems, their importance and applications to metal forming processes, computer-aided analysis of metalworking processes, formability analysis, mathematical modeling and case studies of individual processes are presented.

    4. Studies of Metal-Metal Bonded Compounds in Catalysis

      Energy Technology Data Exchange (ETDEWEB)

      Berry, John F. [Univ. of Wisconsin, Madison, WI (United States)

      2018-01-19

      The overall goals of this research are (1) to define the fundamental coordination chemistry underlying successful catalytic transformations promoted by metal-metal bonded compounds, and (2) to explore new chemical transformations that occur at metal-metal bonded sites that could lead to the discovery of new catalytic processes. Transformations of interest include metal-promoted reactions of carbene, nitrene, or nitrido species to yield products with new C–C and C–N bonds, respectively. The most promising suite of transition metal catalysts for these transformations is the set of metal-metal bonded coordination compounds of Ru and Rh of the general formula M2(ligand)4, where M = Ru or Rh and ligand = a monoanionic, bridging ligand such as acetate. Development of new catalysts and improvement of catalytic conditions have been stymied by a general lack of knowledge about the nature of highly reactive intermediates in these reactions, the knowledge that is to be supplied by this work. Our three specific objectives for this year have been (A) to trap, isolate, and characterize new reactive intermediates of general relevance to catalysis, (B) to explore the electronic structure and reactivity of these unusual species, and how these two properties are interrelated, and (C) to use our obtained mechanistic knowledge to design new catalysts with a focus on Earth-abundant first-row transition metal compounds.

    5. MetalS(3), a database-mining tool for the identification of structurally similar metal sites.

      Science.gov (United States)

      Valasatava, Yana; Rosato, Antonio; Cavallaro, Gabriele; Andreini, Claudia

      2014-08-01

      We have developed a database search tool to identify metal sites having structural similarity to a query metal site structure within the MetalPDB database of minimal functional sites (MFSs) contained in metal-binding biological macromolecules. MFSs describe the local environment around the metal(s) independently of the larger context of the macromolecular structure. Such a local environment has a determinant role in tuning the chemical reactivity of the metal, ultimately contributing to the functional properties of the whole system. The database search tool, which we called MetalS(3) (Metal Sites Similarity Search), can be accessed through a Web interface at http://metalweb.cerm.unifi.it/tools/metals3/ . MetalS(3) uses a suitably adapted version of an algorithm that we previously developed to systematically compare the structure of the query metal site with each MFS in MetalPDB. For each MFS, the best superposition is kept. All these superpositions are then ranked according to the MetalS(3) scoring function and are presented to the user in tabular form. The user can interact with the output Web page to visualize the structural alignment or the sequence alignment derived from it. Options to filter the results are available. Test calculations show that the MetalS(3) output correlates well with expectations from protein homology considerations. Furthermore, we describe some usage scenarios that highlight the usefulness of MetalS(3) to obtain mechanistic and functional hints regardless of homology.

    6. Ion implantation and amorphous metals

      International Nuclear Information System (INIS)

      Hohmuth, K.; Rauschenbach, B.

      1981-01-01

      This review deals with ion implantation of metals in the high concentration range for preparing amorphous layers (>= 10 at%, implantation doses > 10 16 ions/cm 2 ). Different models are described concerning formation of amorphous phases of metals by ion implantation and experimental results are given. The study of amorphous phases has been carried out by the aid of Rutherford backscattering combined with the channeling technique and using transmission electron microscopy. The structure of amorphous metals prepared by ion implantation has been discussed. It was concluded that amorphous metal-metalloid compounds can be described by a dense-random-packing structure with a great portion of metal atoms. Ion implantation has been compared with other techniques for preparing amorphous metals and the adventages have been outlined

    7. Metal Carbides for Biomass Valorization

      Directory of Open Access Journals (Sweden)

      Carine E. Chan-Thaw

      2018-02-01

      Full Text Available Transition metal carbides have been utilized as an alternative catalyst to expensive noble metals for the conversion of biomass. Tungsten and molybdenum carbides have been shown to be effective catalysts for hydrogenation, hydrodeoxygenation and isomerization reactions. The satisfactory activities of these metal carbides and their low costs, compared with noble metals, make them appealing alternatives and worthy of further investigation. In this review, we succinctly describe common synthesis techniques, including temperature-programmed reaction and carbothermal hydrogen reduction, utilized to prepare metal carbides used for biomass transformation. Attention will be focused, successively, on the application of transition metal carbide catalysts in the transformation of first-generation (oils and second-generation (lignocellulose biomass to biofuels and fine chemicals.

    8. Recent Advances in Antimicrobial Hydrogels Containing Metal Ions and Metals/Metal Oxide Nanoparticles

      Directory of Open Access Journals (Sweden)

      Fazli Wahid

      2017-11-01

      Full Text Available Recently, the rapid emergence of antibiotic-resistant pathogens has caused a serious health problem. Scientists respond to the threat by developing new antimicrobial materials to prevent or control infections caused by these pathogens. Polymer-based nanocomposite hydrogels are versatile materials as an alternative to conventional antimicrobial agents. Cross-linking of polymeric materials by metal ions or the combination of polymeric hydrogels with nanoparticles (metals and metal oxide is a simple and effective approach for obtaining a multicomponent system with diverse functionalities. Several metals and metal oxides such as silver (Ag, gold (Au, zinc oxide (ZnO, copper oxide (CuO, titanium dioxide (TiO2 and magnesium oxide (MgO have been loaded into hydrogels for antimicrobial applications. The incorporation of metals and metal oxide nanoparticles into hydrogels not only enhances the antimicrobial activity of hydrogels, but also improve their mechanical characteristics. Herein, we summarize recent advances in hydrogels containing metal ions, metals and metal oxide nanoparticles with potential antimicrobial properties.

    9. Refractory metal based superalloys

      International Nuclear Information System (INIS)

      Alonso, Paula R.; Vicente, Eduardo E.; Rubiolo, Gerardo H.

      1999-01-01

      Refractory metals are looked as promising materials for primary circuits in fission reactors and even as fusion reactor components. Indeed, superalloys could be developed which take advantage of their high temperature properties together with the benefits of a two- phase (intermetallic compound-refractory metal matrix) coherent structure. In 1993, researchers of the Office National d'Etudes et de Recherches Aerospatiales of France reported the observation of such a coherent structure in the Ta-Ti-Zr-Al-Nb-Mo system although the exact composition is not reported. The intermetallic compound would be Ti 2 AlMo based. However, the formation of this compound and its possible coexistence with a disordered bcc phase in the ternary system Ti-Al-Mo is a controversial subject in the related literature. In this work we develop a technique to obtain homogeneous alloys samples with 50 Ti-25 Al-25 Mo composition. The resulting specimens were characterized by optical and electronic metallography (SEM), microprobe composition measurements (EPMA) and X-ray diffraction (XRD) analyses. The results show the evidence for a bcc (A2→B2) ordering reaction in the Ti-Al-Mo system in the 50 Ti-25 Al-25 Mo composition. (author)

    10. Microbiological metal extraction processes

      International Nuclear Information System (INIS)

      Torma, A.E.

      1991-01-01

      Application of biotechnological principles in the mineral processing, especially in hydrometallurgy, has created new opportunities and challenges for these industries. During the 1950's and 60's, the mining wastes and unused complex mineral resources have been successfully treated in bacterial assisted heap and dump leaching processes for copper and uranium. The interest in bio-leaching processes is the consequence of economic advantages associated with these techniques. For example, copper can be produced from mining wastes for about 1/3 to 1/2 of the costs of copper production by the conventional smelting process from high-grade sulfide concentrates. The economic viability of bio leaching technology lead to its world wide acceptance by the extractive industries. During 1970's this technology grew into a more structured discipline called 'bio hydrometallurgy'. Currently, bio leaching techniques are ready to be used, in addition to copper and uranium, for the extraction of cobalt, nickel, zinc, precious metals and for the desulfurization of high-sulfur content pyritic coals. As a developing technology, the microbiological leaching of the less common and rare metals has yet to reach commercial maturity. However, the research in this area is very active. In addition, in a foreseeable future the biotechnological methods may be applied also for the treatment of high-grade ores and mineral concentrates using adapted native and/or genetically engineered microorganisms. (author)

    11. Towards Strange Metallic Holography

      International Nuclear Information System (INIS)

      2010-01-01

      We initiate a holographic model building approach to 'strange metallic' phenomenology. Our model couples a neutral Lifshitz-invariant quantum critical theory, dual to a bulk gravitational background, to a finite density of gapped probe charge carriers, dually described by D-branes. In the physical regime of temperature much lower than the charge density and gap, we exhibit anomalous scalings of the temperature and frequency dependent conductivity. Choosing the dynamical critical exponent z appropriately we can match the non-Fermi liquid scalings, such as linear resistivity, observed in strange metal regimes. As part of our investigation we outline three distinct string theory realizations of Lifshitz geometries: from F theory, from polarized branes, and from a gravitating charged Fermi gas. We also identify general features of renormalization group flow in Lifshitz theories, such as the appearance of relevant charge-charge interactions when z (ge) 2. We outline a program to extend this model building approach to other anomalous observables of interest such as the Hall conductivity.

    12. Hydrogen in metals

      International Nuclear Information System (INIS)

      1986-01-01

      The report briefly describes the results of the single projects promoted by the German Council of Research (DFG). The subjects deal with diffusion, effusion, permeation and solubility of hydrogen in metals. They are interesting for many disciplines: metallurgy, physical metallurgy, metal physics, materials testing, welding engineering, chemistry, nuclear physics and solid-state physics. The research projects deal with the following interrelated subjects: solubility of H 2 in steel and effects on embrittlement, influence of H 2 on the fatigue strength of steel as well as the effect of H 2 on welded joints. The studies in solid-state research can be divided into methodological and physico-chemical studies. The methodological studies mainly comprise investigations on the analytical determination of H 2 by means of nuclear-physical reactions (e.g. the 15 N method) and the application of the Moessbauer spectroscopy. Physico-chemical problems are mainly dealt with in studies on interfacial reactions in connection with the absorption of hydrogen and on the diffusion of H 2 in different alloy systems. The properties of materials used for hydrogen storage were the subject of several research projects. 20 contributions were separately recorded for the data bank 'Energy'. (MM) [de

    13. Magnetic metallic multilayers

      International Nuclear Information System (INIS)

      Hood, R.Q.

      1994-04-01

      Utilizing self-consistent Hartree-Fock calculations, several aspects of multilayers and interfaces are explored: enhancement and reduction of the local magnetic moments, magnetic coupling at the interfaces, magnetic arrangements within each film and among non-neighboring films, global symmetry of the systems, frustration, orientation of the various moments with respect to an outside applied field, and magnetic-field induced transitions. Magnetoresistance of ferromagnetic-normal-metal multilayers is found by solving the Boltzmann equation. Results explain the giant negative magnetoresistance encountered in these systems when an initial antiparallel arrangement is changed into a parallel configuration by an external magnetic field. The calculation depends on (1) geometric parameters (thicknesses of layers), (2) intrinsic metal parameters (number of conduction electrons, magnetization, and effective masses in layers), (3) bulk sample properties (conductivity relaxation times), (4) interface scattering properties (diffuse scattering versus potential scattering at the interfaces, and (5) outer surface scattering properties (specular versus diffuse surface scattering). It is found that a large negative magnetoresistance requires considerable asymmetry in interface scattering for the two spin orientations. Features of the interfaces that may produce an asymmetrical spin-dependent scattering are studied: varying interfacial geometric random roughness with no lateral coherence, correlated (quasi-periodic) roughness, and varying chemical composition of the interfaces. The interplay between these aspects of the interfaces may enhance or suppress the magnetoresistance, depending on whether it increases or decreases the asymmetry in the spin-dependent scattering of the conduction electrons

    14. Metallic hydrogen research

      International Nuclear Information System (INIS)

      Burgess, T.J.; Hawke, R.S.

      1978-01-01

      Theoretical studies predict that molecular hydrogen can be converted to the metallic phase at very high density and pressure. These conditions were achieved by subjecting liquid hydrogen to isentropic compression in a magnetic-flux compression device. Hydrogen became electrically conducting at a density of about 1.06 g/cm 3 and a calculated pressure of about 2 Mbar. In the experimental device, a cylindrical liner, on implosion by high explosive, compresses a magnetic flux which in turn isentropically compresses a hydrogen sample; coaxial conical anvils prevent escape of the sample during compression. One anvil contains a coaxial cable that uses alumina ceramic as an insulator; this probe allows continuous measurement of the electrical conductivity of the hydrogen. A flash x-ray radiograph exposed during the experiment records the location of the sample-tube boundaries and permits calculation of the sample density. The theoretical underpinnings of the metallic transition of hydrogen are briefly summarized, and the experimental apparatus and technique, analytical methods, and results are described. 9 figures

    15. Clean Metal Casting

      Energy Technology Data Exchange (ETDEWEB)

      Makhlouf M. Makhlouf; Diran Apelian

      2002-02-05

      The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components.

    16. Progress of biodegradable metals

      Directory of Open Access Journals (Sweden)

      Huafang Li

      2014-10-01

      Full Text Available Biodegradable metals (BMs are metals and alloys expected to corrode gradually in vivo, with an appropriate host response elicited by released corrosion products, then dissolve completely upon fulfilling the mission to assist with tissue healing with no implant residues. In the present review article, three classes of BMs have been systematically reviewed, including Mg-based, Fe-based and Zn-based BMs. Among the three BM systems, Mg-based BMs, which now have several systems reported the successful of clinical trial results, are considered the vanguards and main force. Fe-based BMs, with pure iron and Fe–Mn based alloys as the most promising, are still on the animal test stage. Zn-based BMs, supposed to have the degradation rate between the fast Mg-based BMs and the slow Fe-based BMs, are a rising star with only several reports and need much further research. The future research and development direction for the BMs are proposed, based on the clinical requirements on controllable degradation rate, prolonged mechanical stability and excellent biocompatibility, by optimization of alloy composition design, regulation on microstructure and mechanical properties, and following surface modification.

    17. Container for liquid metal

      International Nuclear Information System (INIS)

      Abe, Yoshihito; Imazu, Takayuki; Ueda, Sabuo; Ueya, Katsumi.

      1980-01-01

      Purpose: To arrange a vapor trapping member of a specific structure at the inlet part of a cylindrical gap formed by the inner peripheral surface of the circular opening of a container and the outer peripheral surface of a rotary plug thereby to prevent ingress of vapor in the upper part of the cylindrical gap for a long period of time. Constitution: A sealing material receiving tray is fitted to the container side of the inlet part of a cylindrical gap, and a partition plate is fitted to the rotary plug side. The tray is filled with a sealing material consisting of a large number of steel balls, mesh wire gages and the like, and the partition plate is placed in the tray thereby to carry out sealing of the container. Liquid metal vapor evaporating from the liquid level of the liquid metal adheres to the sealing material to fill the gap, and therefore ingress of vapor to the upper part of the cylindrical gap is prevented, and there is no possibility of causing seal cutting due to the use for a long period. (Sekiya, K.)

    18. Clean Metal Casting; FINAL

      International Nuclear Information System (INIS)

      Makhlouf M. Makhlouf; Diran Apelian

      2002-01-01

      The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components

    19. Trees as metal scavengers

      International Nuclear Information System (INIS)

      Hallman, N.

      2000-01-01

      Full text: Tree roots extract metal ions form wet soils in two different ways. At the soil/root hair interface soluble ions in contact with the cellulose wall move through it and enter the cell through the plasmalemma; the semi permeable membrane that encloses every living cell. Some ions, especially those that are part of cellular metabolic processes eg. Na, K, Fe, Mg, S move into the cytoplasm, are bound into organic complexes and travel from cell to cell within the cytoplasm. This requires energy, and the amount of any of these metabolically active ions taken in tends to be regulated by the plant. The movement of the ions from cell to cell is slow, selective, and regulated by requirements of synthesis of for example Mg in the chlorophyll molecule. This means that more Mg is transported to cells of leaves than of cells of roots. This movement of ions is simplistic, or within the cytoplasm. Other ions are swept along in the transpiration stream and enter the complex plumbing system that brings water to the leaves for metabolism and cooling. Water in this apoplastic pathway travels within the pipes (xylem) of the wood and in the cellulose of the walls. It travels along essentially non-living parts of the plant. Ions such as As, Pb, Ni, Cr accumulate in sites such as leaves and bark. Analysis of plant parts can indicate the presence of heavy metals and can give an indication of ore bodies within the root zone

    20. Nodal-chain metals.

      Science.gov (United States)

      Bzdušek, Tomáš; Wu, QuanSheng; Rüegg, Andreas; Sigrist, Manfred; Soluyanov, Alexey A

      2016-10-06

      The band theory of solids is arguably the most successful theory of condensed-matter physics, providing a description of the electronic energy levels in various materials. Electronic wavefunctions obtained from the band theory enable a topological characterization of metals for which the electronic spectrum may host robust, topologically protected, fermionic quasiparticles. Many of these quasiparticles are analogues of the elementary particles of the Standard Model, but others do not have a counterpart in relativistic high-energy theories. A complete list of possible quasiparticles in solids is lacking, even in the non-interacting case. Here we describe the possible existence of a hitherto unrecognized type of fermionic excitation in metals. This excitation forms a nodal chain-a chain of connected loops in momentum space-along which conduction and valence bands touch. We prove that the nodal chain is topologically distinct from previously reported excitations. We discuss the symmetry requirements for the appearance of this excitation and predict that it is realized in an existing material, iridium tetrafluoride (IrF 4 ), as well as in other compounds of this class of materials. Using IrF 4 as an example, we provide a discussion of the topological surface states associated with the nodal chain. We argue that the presence of the nodal-chain fermions will result in anomalous magnetotransport properties, distinct from those of materials exhibiting previously known excitations.

    1. Metal-ceramic joint assembly

      Science.gov (United States)

      Li, Jian

      2002-01-01

      A metal-ceramic joint assembly in which a brazing alloy is situated between metallic and ceramic members. The metallic member is either an aluminum-containing stainless steel, a high chromium-content ferritic stainless steel or an iron nickel alloy with a corrosion protection coating. The brazing alloy, in turn, is either an Au-based or Ni-based alloy with a brazing temperature in the range of 9500 to 1200.degree. C.

    2. Metallization of some simple systems

      International Nuclear Information System (INIS)

      Ross, M.; McMahan, A.K.

      1981-01-01

      We discuss the metallization of Xe, Ar, He, I 2 , H 2 , and N 2 in terms of some recent theoretical work and shock-wave experiments. New shock-wave data on liquid hydrogen and deuterium leads to a predicted pressure above 3 Mbar for the appearance of a monatomic metal phase. We expect CsI to become metallic near 0.8 Mbar

    3. Electronic structure of metallic glasses

      International Nuclear Information System (INIS)

      Oelhafen, P.; Lapka, R.; Gubler, U.; Krieg, J.; DasGupta, A.; Guentherodt, H.J.; Mizoguchi, T.; Hague, C.; Kuebler, J.; Nagel, S.R.

      1981-01-01

      This paper is organized in six sections and deals with (1) the glassy transition metal alloys, their d-band structure, the d-band shifts on alloying and their relation to the alloy heat of formation (ΔH) and the glass forming ability, (2) the glass to crystal phase transition viewed by valence band spectroscopy, (3) band structure calculations, (4) metallic glasses prepared by laser glazing, (5) glassy normal metal alloys, and (6) glassy hydrides

    4. Air and metal hydride battery

      Energy Technology Data Exchange (ETDEWEB)

      Lampinen, M.; Noponen, T. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Applied Thermodynamics

      1998-12-31

      The main goal of the air and metal hydride battery project was to enhance the performance and manufacturing technology of both electrodes to such a degree that an air-metal hydride battery could become a commercially and technically competitive power source for electric vehicles. By the end of the project it was possible to demonstrate the very first prototype of the air-metal hydride battery at EV scale, achieving all the required design parameters. (orig.)

    5. Superconductivity in inhomogeneous granular metals

      International Nuclear Information System (INIS)

      McLean, W.L.

      1980-01-01

      A model of elongated metal ellipsoids imbedded in a granular metal is treated by an effective medium approach to explain the observed temperature dependence of the normal-state conductivity of superconducting granular aluminum. Josephson tunneling is thus still required to account for the superconductivity. The model predicts the same kind of contrasting behavior on opposite sides of the metal-insulator transition as is found in the recent scaling treatment of Anderson localization

    6. Metals extraction from sea water

      International Nuclear Information System (INIS)

      Chryssostomidis, C.; Larue, G.J.; Morgan, D.T.

      1981-01-01

      A method and system for continuously extracting metals from sea water by deploying adsorber sheets in a suitable current of sea water, recovering the adsorber sheets after they become loaded with metal and eluting the metal from the recovered sheets. The system involves the use of hollow, perforated bobbins on which the sheets are rolled as they are recovered and through which elutant is introduced

    7. Corrosion-resistant metal surfaces

      Science.gov (United States)

      Sugama, Toshifumi [Wading River, NY

      2009-03-24

      The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

    8. Alkali metal hafnium oxide scintillators

      Science.gov (United States)

      Bourret-Courchesne, Edith; Derenzo, Stephen E.; Taylor, Scott Edward

      2018-05-08

      The present invention provides for a composition comprising an inorganic scintillator comprising an alkali metal hafnate, optionally cerium-doped, having the formula A2HfO3:Ce; wherein A is an alkali metal having a valence of 1, such as Li or Na; and the molar percent of cerium is 0% to 100%. The alkali metal hafnate are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

    9. Metal hydride compositions and lithium ion batteries

      Energy Technology Data Exchange (ETDEWEB)

      Young, Kwo; Nei, Jean

      2018-04-24

      Heterogeneous metal hydride (MH) compositions comprising a main region comprising a first metal hydride and a secondary region comprising one or more additional components selected from the group consisting of second metal hydrides, metals, metal alloys and further metal compounds are suitable as anode materials for lithium ion cells. The first metal hydride is for example MgH.sub.2. Methods for preparing the composition include coating, mechanical grinding, sintering, heat treatment and quenching techniques.

    10. Alkali metal ion battery with bimetallic electrode

      Science.gov (United States)

      Boysen, Dane A; Bradwell, David J; Jiang, Kai; Kim, Hojong; Ortiz, Luis A; Sadoway, Donald R; Tomaszowska, Alina A; Wei, Weifeng; Wang, Kangli

      2015-04-07

      Electrochemical cells having molten electrodes having an alkali metal provide receipt and delivery of power by transporting atoms of the alkali metal between electrode environments of disparate chemical potentials through an electrochemical pathway comprising a salt of the alkali metal. The chemical potential of the alkali metal is decreased when combined with one or more non-alkali metals, thus producing a voltage between an electrode comprising the molten the alkali metal and the electrode comprising the combined alkali/non-alkali metals.

    11. Antimicrobial Polymers with Metal Nanoparticles

      Science.gov (United States)

      Palza, Humberto

      2015-01-01

      Metals, such as copper and silver, can be extremely toxic to bacteria at exceptionally low concentrations. Because of this biocidal activity, metals have been widely used as antimicrobial agents in a multitude of applications related with agriculture, healthcare, and the industry in general. Unlike other antimicrobial agents, metals are stable under conditions currently found in the industry allowing their use as additives. Today these metal based additives are found as: particles, ions absorbed/exchanged in different carriers, salts, hybrid structures, etc. One recent route to further extend the antimicrobial applications of these metals is by their incorporation as nanoparticles into polymer matrices. These polymer/metal nanocomposites can be prepared by several routes such as in situ synthesis of the nanoparticle within a hydrogel or direct addition of the metal nanofiller into a thermoplastic matrix. The objective of the present review is to show examples of polymer/metal composites designed to have antimicrobial activities, with a special focus on copper and silver metal nanoparticles and their mechanisms. PMID:25607734

    12. Liquid metal heat transfer issues

      International Nuclear Information System (INIS)

      Hoffman, H.W.; Yoder, G.L.

      1984-01-01

      An alkali liquid metal cooled nuclear reactor coupled with an alkali metal Rankine cycle provides a practicable option for space systems/missions requiring power in the 1 to 100 MW(e) range. Thermal issues relative to the use of alkali liquid metals for this purpose are identified as these result from the nature of the alkali metal fluid itself, from uncertainties in the available heat transfer correlations, and from design and performance requirements for system components operating in the earth orbital microgravity environment. It is noted that, while these issues require further attention to achieve optimum system performance, none are of such magnitude as to invalidate this particular space power concept

    13. Metal shadowing for electron microscopy.

      Science.gov (United States)

      Hendricks, Gregory M

      2014-01-01

      Metal shadowing of bacteria, viruses, isolated molecules, and macromolecular assemblies is another high-resolution method for observing the ultrastructure of biological specimens. The actual procedure for producing a metal shadow is relatively simple; a heavy metal is evaporated from a source at an oblique angle to the specimen. The metal atoms pile up on the surfaces that face the source, but the surfaces away from the source are shielded and receive little metal deposit, creating a "shadow." However, the process of producing biological specimens that are suitable for metal shadowing can be very complex. There are a whole host of specimen preparation techniques that can precede metal shadowing, and all provide superior preservation in comparison to air drying, a required step in negative staining procedures. The physical forces present during air drying (i.e., surface tension of the water-air interface) will literally crush most biological specimens as they dry. In this chapter I explain the development of and procedures for the production of biological specimens from macromolecular assemblies (e.g., DNA and RNA), purified isolated molecules (e.g., proteins), and isolated viruses and bacteria preparations suitable for metal shadowing. A variation on this basic technique is to rotate the specimen during the metal deposition to produce a high-resolution three-dimensional rendering of the specimen.

    14. Structural energetics of noble metals

      International Nuclear Information System (INIS)

      Mujibur Rahman, S.M.

      1982-06-01

      Structural energetics of the noble metals, namely Cu, Ag, and Au are investigated by employing a single-parameter pseudopotential. The calculations show that the lowest energy for all of these metals corresponds to FCC - their observed crystal structure. The one-electron contribution to the free energy is found to dominate the structural prediction for these metals. The present investigation strongly emphasizes that the effects due to band hybridization and core-core exchange play a significant role on the structural stability of the noble metals. (author)

    15. Extraterrestrial Metals Processing, Phase I

      Data.gov (United States)

      National Aeronautics and Space Administration — The Extraterrestrial Metals Processing (EMP) system produces ferrosilicon, silicon monoxide, a glassy mixed oxide slag, and smaller amounts of alkali earth...

    16. Electroless metal plating of plastics

      International Nuclear Information System (INIS)

      Krause, L.J.

      1986-01-01

      The product of an electroless plating process is described for plating at least one main group metal directly on a surface of a polymeric substrate comprising the steps of forming a nonaqueous solution containing a metallic salt of an alkali metal in a positive valence state and at least one main group metal in a negative valence state, the main group metal being selected from the group consisting of Ge, Sn, Pb, As, Sb, Bi, Si and Te, selecting an aromatic polymeric substrate reducible by the solublized salt and resistant to degration during the reaction, and carrying out a redox reaction between the salt in solution and the substrate by contacting the solution with the substrate for a sufficient time to oxidize and deposit the main group metal in elemental form to produce a plated substrate. The product is characterized by the plated metal being directly on the surface of the polymeric substrate and the alkali metal being retained in the plated substrate with the substrate being negatively charged with electrons transferred from the main group metal during the redox reaction

    17. Metals, scraps and opportunities; Metales, chatarras y oportunidades

      Energy Technology Data Exchange (ETDEWEB)

      Roman Ortega, F.

      2003-07-01

      This article attempts to focus on the vision that recuperation and recycling of metals is an activity which must attract attention of Mine Engineers, as much for its increasing importance as the fact that the techniques involved are not anything else but adaptation, in certain conditions of the ones used in the treatment and benefit of the metallic ores. (Author)

    18. Metal decontamination for waste minimization using liquid metal refining technology

      International Nuclear Information System (INIS)

      Joyce, E.L. Jr.; Lally, B.; Ozturk, B.; Fruehan, R.J.

      1993-01-01

      The current Department of Energy Mixed Waste Treatment Project flowsheet indicates that no conventional technology, other than surface decontamination, exists for metal processing. Current Department of Energy guidelines require retrievable storage of all metallic wastes containing transuranic elements above a certain concentration. This project is in support of the National Mixed Low Level Waste Treatment Program. Because of the high cost of disposal, it is important to develop an effective decontamination and volume reduction method for low-level contaminated metals. It is important to be able to decontaminate complex shapes where surfaces are hidden or inaccessible to surface decontamination processes and destruction of organic contamination. These goals can be achieved by adapting commercial metal refining processes to handle radioactive and organic contaminated metal. The radioactive components are concentrated in the slag, which is subsequently vitrified; hazardous organics are destroyed by the intense heat of the bath. The metal, after having been melted and purified, could be recycled for use within the DOE complex. In this project, we evaluated current state-of-the-art technologies for metal refining, with special reference to the removal of radioactive contaminants and the destruction of hazardous organics. This evaluation was based on literature reports, industrial experience, plant visits, thermodynamic calculations, and engineering aspects of the various processes. The key issues addressed included radioactive partitioning between the metal and slag phases, minimization of secondary wastes, operability of the process subject to widely varying feed chemistry, and the ability to seal the candidate process to prevent the release of hazardous species

    19. Plasmons in metallic monolayer and bilayer transition metal dichalcogenides

      DEFF Research Database (Denmark)

      Andersen, Kirsten; Thygesen, Kristian S.

      2013-01-01

      We study the collective electronic excitations in metallic single-layer and bilayer transition metal dichalcogenides (TMDCs) using time dependent density functional theory in the random phase approximation. For very small momentum transfers (below q≈0.02 Å−1), the plasmon dispersion follows the √q...

    20. Nanostructured Anodic Multilayer Dielectric Stacked Metal-Insulator-Metal Capacitors.

      Science.gov (United States)

      Karthik, R; Kannadassan, D; Baghini, Maryam Shojaei; Mallick, P S

      2015-12-01

      This paper presents the fabrication of Al2O3/TiO2/Al2O3 metal-insulator-metal (MIM) capacitor using anodization technique. High capacitance density of > 3.5 fF/μm2, low quadratic voltage coefficient of capacitance of dielectric stack required for high performance MIM capacitor.

    1. Plasma damage in floating metal-insulator-metal capacitors

      NARCIS (Netherlands)

      Ackaert, Jan; Wang, Zhichun; De Backer, E.; Coppens, P.

      2002-01-01

      In this paper, charging induced damage (CID) to metal-insulator-metal capacitors (MIMCs), is reported. CID does not necessarily lead to direct yield loss, but may also induce latent damage leading to reliability losses. The damage is caused by the build up of a voltage potential difference between

    2. Charging damage in floating metal-insulator-metal capacitors

      NARCIS (Netherlands)

      Ackaert, Jan; Wang, Zhichun; De Backer, E.; Coppens, P.

      2002-01-01

      In this paper, charging induced damage (CID) to metal-insulator-metal capacitors (MIMC) is reported. The damage is caused by the build up of a voltage potential difference between the two plates of the capacitor. A simple logarithmic relation is discovered between the damage by this voltage

    3. Plasma Damage in Floating Metal-Insulator-Metal Capacitors

      NARCIS (Netherlands)

      Ackaert, Jan; Wang, Zhichun; Backer, E.; Coppens, P.

      2001-01-01

      In this paper, charging induced damage (CID) to metal-insulator-metal capacitors (MIMCs), is reported. CID does not necessarily lead to direct yield loss, but may also induce latent damage leading to reliability losses. The damage is caused by the build up of a voltage potential difference between

    4. Plasma methods for metals recovery from metal-containing waste.

      Science.gov (United States)

      Changming, Du; Chao, Shang; Gong, Xiangjie; Ting, Wang; Xiange, Wei

      2018-04-27

      Metal-containing waste, a kind of new wastes, has a great potential for recycling and is also difficult to deal with. Many countries pay more and more attention to develop the metal recovery process and equipment of this kind of waste as raw material, so as to solve the environmental pollution and comprehensively utilize the discarded metal resources. Plasma processing is an efficient and environmentally friendly way for metal-containing waste. This review mainly discuss various metal-containing waste types, such as printed circuit boards (PCBs), red mud, galvanic sludge, Zircon, aluminium dross and incinerated ash, and the corresponding plasma methods, which include DC extended transferred arc plasma reactor, DC non-transferred arc plasma torch, RF thermal plasma reactor and argon and argon-hydrogen plasma jets. In addition, the plasma arc melting technology has a better purification effect on the extraction of useful metals from metal-containing wastes, a great capacity of volume reduction of waste materials, and a low leaching toxicity of solid slag, which can also be used to deal with all kinds of metal waste materials, having a wide range of applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

    5. Metal Hydride Compression

      Energy Technology Data Exchange (ETDEWEB)

      Johnson, Terry A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Bowman, Robert [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smith, Barton [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Anovitz, Lawrence [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jensen, Craig [Hawaii Hydrogen Carriers LLC, Honolulu, HI (United States)

      2017-07-01

      Conventional hydrogen compressors often contribute over half of the cost of hydrogen stations, have poor reliability, and have insufficient flow rates for a mature FCEV market. Fatigue associated with their moving parts including cracking of diaphragms and failure of seal leads to failure in conventional compressors, which is exacerbated by the repeated starts and stops expected at fueling stations. Furthermore, the conventional lubrication of these compressors with oil is generally unacceptable at fueling stations due to potential fuel contamination. Metal hydride (MH) technology offers a very good alternative to both conventional (mechanical) and newly developed (electrochemical, ionic liquid pistons) methods of hydrogen compression. Advantages of MH compression include simplicity in design and operation, absence of moving parts, compactness, safety and reliability, and the possibility to utilize waste industrial heat to power the compressor. Beyond conventional H2 supplies of pipelines or tanker trucks, another attractive scenario is the on-site generating, pressuring and delivering pure H2 at pressure (≥ 875 bar) for refueling vehicles at electrolysis, wind, or solar generating production facilities in distributed locations that are too remote or widely distributed for cost effective bulk transport. MH hydrogen compression utilizes a reversible heat-driven interaction of a hydride-forming metal alloy with hydrogen gas to form the MH phase and is a promising process for hydrogen energy applications [1,2]. To deliver hydrogen continuously, each stage of the compressor must consist of multiple MH beds with synchronized hydrogenation & dehydrogenation cycles. Multistage pressurization allows achievement of greater compression ratios using reduced temperature swings compared to single stage compressors. The objectives of this project are to investigate and demonstrate on a laboratory scale a two-stage MH hydrogen (H2) gas compressor with a

    6. Catalytic production of metal carbonyls from metal oxides

      Science.gov (United States)

      Sapienza, Richard S.; Slegeir, William A.; Foran, Michael T.

      1984-01-01

      This invention relates to the formation of metal carbonyls from metal oxides and specially the formation of molybdenum carbonyl and iron carbonyl from their respective oxides. Copper is used here in admixed form or used in chemically combined form as copper molybdate. The copper/metal oxide combination or combined copper is utilized with a solvent, such as toluene and subjected to carbon monoxide pressure of 25 atmospheres or greater at about 150.degree.-260.degree. C. The reducing metal copper is employed in catalytic concentrations or combined concentrations as CuMoO.sub.4 and both hydrogen and water present serve as promoters. It has been found that the yields by this process have been salutary and that additionally the catalytic metal may be reused in the process to good effect.

    7. Heavy metal movement in metal-contaminated soil profiles

      Energy Technology Data Exchange (ETDEWEB)

      Li, Zhenbin; Shuman, L.M. [Univ. of Georgia, Griffin, GA (United States)

      1996-10-01

      Heavy metal movement in soil profiles is a major environmental concern because even slow transport through the soil may eventually lead to deterioration of groundwater quality. In this study, three metal-contaminated soil (Fuquay, Dothan, and Clarendon) were selected from cropland were a high-metal flue dust had been applied annually for 6 years to raise soil pH, with application ending 4 years before sampling. One uncontaminated soil (Tifton) from the same physiographic area was also sampled as a control. Soil samples were collected in 15-cm increments from the surface to 105 cm in depth. Total contents of Zn, Cd, and Pb in the soils samples were determined. To better understand metal movement in relation to metal fractions in the soil profile, soil samples were also extracted sequentially for exchangeable (EXC), organic matter (OM), Mn oxide (MNO), amorphous Fe oxide (AFEO), crystalline Fe oxide (CFEO), and residual (RES) fractions. 35 refs., 6 figs., 2 tabs.

    8. Metal-in-metal localized surface plasmon resonance

      Energy Technology Data Exchange (ETDEWEB)

      Smith, G B; Earp, A A, E-mail: g.smith@uts.edu.au [Department of Physics and Advanced Materials and Institute of Nanoscale Technology, University of Technology, Sydney, PO Box 123, Broadway NSW 2007 (Australia)

      2010-01-08

      Anomalous strong resonances in silver and gold nanoporous thin films which conduct are found to arise from isolated metal nano-islands separated from the surrounding percolating metal network by a thin loop of insulator. This observed resonant optical response is modelled. The observed peak position is in agreement with the observed average dimensions of the silver core and insulator shell. As the insulating ring thickness shrinks, the resonance moves to longer wavelengths and strengthens. This structure is the Babinet's principle counterpart of dielectric core-metal shell nanoparticles embedded in dielectric. Like for the latter, tuning of resonant absorption is possible, but here the matrix reflects rather than transmits, and tuning to longer wavelengths is more practical. A new class of metal mirror occurring as a single thin layer is identified using the same resonances in dense metal mirrors. Narrow band deep localized dips in reflectance result.

    9. Metal-in-metal localized surface plasmon resonance

      Science.gov (United States)

      Smith, G. B.; Earp, A. A.

      2010-01-01

      Anomalous strong resonances in silver and gold nanoporous thin films which conduct are found to arise from isolated metal nano-islands separated from the surrounding percolating metal network by a thin loop of insulator. This observed resonant optical response is modelled. The observed peak position is in agreement with the observed average dimensions of the silver core and insulator shell. As the insulating ring thickness shrinks, the resonance moves to longer wavelengths and strengthens. This structure is the Babinet's principle counterpart of dielectric core-metal shell nanoparticles embedded in dielectric. Like for the latter, tuning of resonant absorption is possible, but here the matrix reflects rather than transmits, and tuning to longer wavelengths is more practical. A new class of metal mirror occurring as a single thin layer is identified using the same resonances in dense metal mirrors. Narrow band deep localized dips in reflectance result.

    10. Infection or metal hypersensitivity? The diagnostic challenge of failure in metal-on-metal bearings.

      LENUS (Irish Health Repository)

      Galbraith, John G

      2011-04-01

      The use of second generation metal-on-metal hip articulations has gained favour in the past few years. A hypersensitivity reaction to the metal-on-metal bearing, although rare, is a reported complication and is a novel mode of failure of these implants. Differentiating failure secondary to infection from failure secondary to metal hypersensitivity represents a significant diagnostic challenge. A retrospective review of all cases of hip arthroplasty using metal-on-metal bearings over a 5-year period at a tertiary referral centre identified 3 cases of failure secondary to metal hypersensitivity. Clinical presentation, serological markers, radiological imaging and histological analysis of all cases identified were evaluated. Histological analysis of periprosthetic tissue in all 3 cases identified characteristic features such as perivascular lymphocytic aggregates and chronic inflammation consistent with aseptic lymphocytic vasculitis-associated lesions (ALVAL). This study highlights that failure secondary to metal hypersensitivity must be considered in patients presenting with the reappearance of persistent pain, marked joint effusion, and the development of early osteolysis in the absence of infection.

    11. Spherical rhenium metal powder

      International Nuclear Information System (INIS)

      Leonhardt, T.; Moore, N.; Hamister, M.

      2001-01-01

      The development of a high-density, spherical rhenium powder (SReP) possessing excellent flow characteristics has enabled the use of advanced processing techniques for the manufacture of rhenium components. The techniques that were investigated were vacuum plasma spraying (VPS), direct-hot isostatic pressing (D-HIP), and various other traditional powder metallurgy processing methods of forming rhenium powder into near-net shaped components. The principal disadvantages of standard rhenium metal powder (RMP) for advanced consolidation applications include: poor flow characteristics; high oxygen content; and low and varying packing densities. SReP will lower costs, reduce processing times, and improve yields when manufacturing powder metallurgy rhenium components. The results of the powder characterization of spherical rhenium powder and the consolidation of the SReP are further discussed. (author)

    12. Expanding hollow metal rings

      Science.gov (United States)

      Peacock, Harold B [Evans, GA; Imrich, Kenneth J [Grovetown, GA

      2009-03-17

      A sealing device that may expand more planar dimensions due to internal thermal expansion of a filler material. The sealing material is of a composition such that when desired environment temperatures and internal actuating pressures are reached, the sealing materials undergoes a permanent deformation. For metallic compounds, this permanent deformation occurs when the material enters the plastic deformation phase. Polymers, and other materials, may be using a sealing mechanism depending on the temperatures and corrosivity of the use. Internal pressures are generated by either rapid thermal expansion or material phase change and may include either liquid or solid to gas phase change, or in the gaseous state with significant pressure generation in accordance with the gas laws. Sealing material thickness and material composition may be used to selectively control geometric expansion of the seal such that expansion is limited to a specific facing and or geometric plane.

    13. Metallic Fuels Handbook

      Energy Technology Data Exchange (ETDEWEB)

      Janney, Dawn E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Papesch, Cynthia A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Burkes, Douglas E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cole, James I. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Fielding, Randall S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Frank, Steven M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hartmann, Thomas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hyde, Timothy A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Keiser, Jr., Dennis D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kennedy, J. Rory [Idaho National Lab. (INL), Idaho Falls, ID (United States); Maddison, Andrew [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mariani, Robert D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Middlemas, Scott C. [Idaho National Lab. (INL), Idaho Falls, ID (United States); O' Holleran, Thomas P. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sencer, Bulent H. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Squires, Leah N. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

      2017-08-07

      This is not a typical External Report--It is a Handbook. No Abstract is involved. This includes both Parts 1 and 2. The Metallic Fuels Handbook summarizes currently available information about phases and phase diagrams, heat capacity, thermal expansion, and thermal conductivity of elements and alloys in the U-Pu-Zr-Np-Am-La-Ce-Pr-Nd system. Although many sections are reviews and updates of material in previous versions of the Handbook [1, 2], this revision is the first to include alloys with four or more elements. In addition to presenting information about materials properties, the handbook attempts to provide information about how well each property is known and how much variation exists between measurements. Although it includes some results from models, its primary focus is experimental data.

    14. Vacancies in transition metals

      International Nuclear Information System (INIS)

      Allan, G.; Lannoo, M.

      1976-01-01

      A calculation of the formation energy and volume for a vacancy in transition metals is described. A tight-binding scheme is used for the d band and a Born-Mayer type potential to account for the repulsive part of the energy at small distances. The results show that the relaxation energy is small in all cases, less than 0.1 eV. This seems to be coherent with the good agreement obtained for the theoretical and experimental values of the formation energy Esub(F)sup(V) of the vacancy, without including relaxation. The center of the transitional series is found to give a contraction (Formation volume of order -0.4 at.vol.) whereas the edges are found to produce dilations. (author)

    15. Alkaline earth metals

      International Nuclear Information System (INIS)

      Brown, Paul L.; Ekberg, Christian

      2016-01-01

      The beryllium ion has a relatively small ionic radius. As a consequence of this small size, its hydrolysis reactions begin to occur at a relatively low pH. To determine the stability and solubility constants, however, the Gibbs energy of the beryllium ion is required. In aqueous solution calcium, like the other alkaline earth metals, only exists as a divalent cation. The size of the alkaline earth cations increases with increasing atomic number, and the calcium ion is bigger than the magnesium ion. The hydrolysis of barium(II) is weaker than that of strontium(II) and also occurs in quite alkaline pH solutions, and similarly, only the species barium hydroxide has been detected. There is only a single experimental study on the hydrolysis of radium. As with the stability constant trend, it would be expected that the enthalpy of radium would be lower than that of barium due to the larger ionic radius.

    16. Closed metal supports

      Energy Technology Data Exchange (ETDEWEB)

      Dolotov, N P; Afanas' yev, Yu V; Brednev, V A; Nuzhadikhin, A G; Tsiplakov, B V; Uskov, I T

      1980-08-30

      A closed metal support system that has a specific profile includes roof timber, ledger and roof timber. For convenience of transport, assembly, disassembly and repeated use during operation of an extraction powered system, the uprights in the central part are made sectional and are connected to one another by a hinge for folding into transport position. Longitudinal openings are made at the ends of the uprights in order to provide strength by creating flexibility in the hinged connections. The hinged connections of the sectional uprights have elastic gaskets. For convenience in folding the reinforcement, the ends of the uprights of the roof timber and ledger have the shape of a channel at junctions of their hinged connection.

    17. Metallic Magnetic Nanoparticles

      Directory of Open Access Journals (Sweden)

      A. Hernando

      2005-01-01

      Full Text Available In this paper, we reviewed some relevant aspects of the magnetic properties of metallic nanoparticles with small size (below 4 nm, covering the size effects in nanoparticles of magnetic materials, as well as the appearance of magnetism at the nanoscale in materials that are nonferromagnetic in bulk. These results are distributed along the text that has been organized around three important items: fundamental magnetic properties, different fabrication procedures, and characterization techniques. A general introduction and some experimental results recently obtained in Pd and Au nanoparticles have also been included. Finally, the more promising applications of magnetic nanoparticles in biomedicine are indicated. Special care was taken to complete the literature available on the subject.

    18. Flexible Laser Metal Cutting

      DEFF Research Database (Denmark)

      Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

      2014-01-01

      This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...... possess, despite their wide use in industry, limitations regarding speed and geometry. Research trends point towards remote laser cutting techniques which can improve speed and geometrical freedom and hereby the competitiveness of laser cutting compared to fixed-tool-based cutting technology...... such as punching. This paper presents the concepts and preliminary test results of the ROBOCUT laser cutting technology, a technology which potentially can revolutionise laser cutting....

    19. Synthesis metal nanoparticle

      Science.gov (United States)

      Bunge, Scott D.; Boyle, Timothy J.

      2005-08-16

      A method for providing an anhydrous route for the synthesis of amine capped coinage-metal (copper, silver, and gold) nanoparticles (NPs) using the coinage-metal mesityl (mesityl=C.sub.6 H.sub.2 (CH.sub.3).sub.3 -2,4,6) derivatives. In this method, a solution of (Cu(C.sub.6 H.sub.2 (CH.sub.3).sub.3).sub.5, (Ag(C.sub.6 H.sub.2 (CH.sub.3).sub.3).sub.4, or (Au(C.sub.6 H.sub.2 (CH.sub.3).sub.3).sub.5 is dissolved in a coordinating solvent, such as a primary, secondary, or tertiary amine; primary, secondary, or tertiary phosphine, or alkyl thiol, to produce a mesityl precursor solution. This solution is subsequently injected into an organic solvent that is heated to a temperature greater than approximately 100.degree. C. After washing with an organic solvent, such as an alcohol (including methanol, ethanol, propanol, and higher molecular-weight alcohols), oxide free coinage NP are prepared that could be extracted with a solvent, such as an aromatic solvent (including, for example, toluene, benzene, and pyridine) or an alkane (including, for example, pentane, hexane, and heptane). Characterization by UV-Vis spectroscopy and transmission electron microscopy showed that the NPs were approximately 9.2.+-.2.3 nm in size for Cu.degree., (no surface oxide present), approximately 8.5.+-.1.1 nm Ag.degree. spheres, and approximately 8-80 nm for Au.degree..

    20. Blackletter logotypes and metal music

      DEFF Research Database (Denmark)

      Vestergaard, Vitus

      2016-01-01

      Text and band logos based on blackletter scripts are a common sight in visual metal music culture such as on album covers. This article develops a framework for analysing the affinity between blackletter script and metal music. The analytical framework includes five themes: genre tradition, relig...

    1. Metal Working and Welding Operations.

      Science.gov (United States)

      Marine Corps Inst., Washington, DC.

      This student guide, one of a series of correspondence training courses designed to improve the job performance of members of the Marine Corps, deals with the skills needed by metal workers and welders. Addressed in the six individual units of the course are the following topics: weldable metals and their alloys, arc welding, gas welding,…

    2. Behavior of Metals in Soils

      Science.gov (United States)

      One of the major issues of concern to the Forum is the mobility of metals in soils as related to subsurface remediation. For the purposes of this Issue Paper, those metals most commonly found at Superfund sites will be discussed in terms of the processes..

    3. Radioactive materials in recycled metals.

      Science.gov (United States)

      Lubenau, J O; Yusko, J G

      1995-04-01

      In recent years, the metal recycling industry has become increasingly aware of an unwanted component in metal scrap--radioactive material. Worldwide, there have been 35 instances where radioactive sources were unintentionally smelted in the course of recycling metal scrap. In some cases contaminated metal consumer products were distributed internationally. In at least one case, serious radiation exposures of workers and the public occurred. Radioactive material appearing in metal scrap includes sources subject to licensing under the Atomic Energy Act and also naturally occurring radioactive material. U.S. mills that have smelted a radioactive source face costs resulting from decontamination, waste disposal, and lost profits that range from 7 to 23 million U.S. dollars for each event. To solve the problem, industry and the government have jointly undertaken initiatives to increase awareness of the problem within the metal recycling industry. Radiation monitoring of recycled metal scrap is being performed increasingly by mills and, to a lesser extent, by scrap processors. The monitoring does not, however, provide 100% protection. Improvements in regulatory oversight by the government could stimulate improved accounting and control of licensed sources. However, additional government effort in this area must be reconciled with competing priorities in radiation safety and budgetary constraints. The threat of radioactive material in recycled metal scrap will continue for the foreseeable future and, thus, poses regulatory policy challenges for both developed and developing nations.

    4. Water tube liquid metal control

      International Nuclear Information System (INIS)

      Campbell, J.W.E.

      1981-01-01

      An improved heat exchanger for use in liquid metal cooled nuclear power reactors is described in which the heat is transferred between the flow of liquid metal which is to be cooled and a forced flow of liquid which is wholly or partly evaporated. (U.K.)

    5. Metal footprint linked to economy

      Science.gov (United States)

      Burke, Paul J.

      2018-04-01

      The annual quantity of metal being used by humans has been on the rise. A new analysis of 43 major economies reveals the extent to which year-to-year fluctuations in metal footprints have been in lockstep with countries' economic growth and changes in investment spending.

    6. Knowledge-based metals & materials

      OpenAIRE

      Sasson, Amir

      2011-01-01

      This study presents the Norwegian metal and material industry (defined as all metal and material related firms located in Norway, regardless of ownership) and evaluates the industry according to the underlying dimensions of a global knowledge hub - cluster attractiveness, education attractiveness, talent attractiveness, R&D and innovation attractiveness, ownership attractiveness, environmental attractiveness and cluster dynamics.

    7. Zirconium based bulk metallic glasses

      International Nuclear Information System (INIS)

      Dey, G.K.; Neogy, S.; Savalia, R.T.; Tewari, R.; Srivastava, D.; Banerjee, S.

      2006-01-01

      Metallic glasses have come into prominence in recent times because their nanocrystalline atomic arrangement imparts many useful and unusual properties to these metallic solids. In this study, bulk glasses have been obtained in Zr based multicomponent alloy by induction melting these alloys in silica crucibles and casting these in form of rods 3 and 6 mm in diameter in a copper mould

    8. Epidemiological Approaches to Metal Toxicology

      DEFF Research Database (Denmark)

      Grandjean, Philippe; Budtz-Jørgensen, Esben

      2014-01-01

      for testing and further refining methods for study design and data analysis. In contrast to most organic compounds, metals are not broken down, and many of them are retained in the body for long periods, thereby facilitating exposure assessment. In conjunction with the use of inexpensive metal analytical...

    9. Liquid metal cooled nuclear reactor

      International Nuclear Information System (INIS)

      Leigh, K.M.

      1980-01-01

      A liquid metal cooled nuclear reactor is described, wherein coolant is arranged to be flowed upwardly through a fuel assembly and having one or more baffles located above the coolant exit of the fuel assembly, the baffles being arranged so as to convert the upwardly directed motion of liquid metal coolant leaving the fuel assembly into a substantially horizontal motion. (author)

    10. Nanostructured metal-polyaniline composites

      Science.gov (United States)

      Wang, Hsing-Lin; Li, Wenguang; Bailey, James A.; Gao, Yuan

      2010-08-31

      Metal-polyaniline (PANI) composites are provided together with a process of preparing such composites by an electrodeless process. The metal of the composite can have nanoscale structural features and the composites can be used in applications such as catalysis for hydrogenation reactions and for analytical detection methods employing SERS.

    11. Heavy metals and soil microbes

      NARCIS (Netherlands)

      Giller, K.E.; Witter, E.; McGrath, S.

      2009-01-01

      The discovery in the early 1980s that soil microorganisms, and in particular the symbiotic bacteria Rhizobium, were highly sensitive to heavy metals initiated a new line of research. This has given us important insights into a range of topics: ecotoxicology, bioavailability of heavy metals, the role

    12. General aspects of metal toxicity.

      Science.gov (United States)

      Kozlowski, H; Kolkowska, P; Watly, J; Krzywoszynska, K; Potocki, S

      2014-01-01

      This review is focused on the general mechanisms of metal toxicity in humans. The possible and mainly confirmed mechanisms of their action are discussed. The metals are divided into four groups due to their toxic effects. First group comprises of metal ions acting as Fenton reaction catalyst mainly iron and copper. These types of metal ions participate in generation of the reactive oxygen species. Metals such as nickel, cadmium and chromium are considered as carcinogenic agents. Aluminum, lead and tin are involved in neurotoxicity. The representative of the last group is mercury, which may be considered as a generally toxic metal. Fenton reaction is a naturally occurring process producing most active oxygen species, hydroxyl radical: Fe(2+) + He2O2 ↔ Fe(3+) + OH(-) + OH(•) It is able to oxidize most of the biomolecules including DNA, proteins, lipids etc. The effect of toxicity depends on the damage of molecules i.e. production site of the hydroxyl radical. Chromium toxicity depends critically on its oxidation state. The most hazardous seems to be Cr(6+) (chromates) which are one of the strongest inorganic carcinogenic agents. Cr(6+) species act also as oxidative agents damaging among other nucleic acids. Redox inactive Al(3+), Cd(2+) or Hg(2+) may interfere with biology of other metal ions e.g. by occupying metal binding sites in biomolecules. All these aspects will be discussed in the review.

    13. Decomposition of metal nitrate solutions

      International Nuclear Information System (INIS)

      Haas, P.A.; Stines, W.B.

      1982-01-01

      Oxides in powder form are obtained from aqueous solutions of one or more heavy metal nitrates (e.g. U, Pu, Th, Ce) by thermal decomposition at 300 to 800 deg C in the presence of about 50 to 500% molar concentration of ammonium nitrate to total metal. (author)

    14. Low-dimensional molecular metals

      CERN Document Server

      Toyota, Naoki; Muller, Jens

      2007-01-01

      Assimilating research in the field of low-dimensional metals, this monograph provides an overview of the status of research on quasi-one- and two-dimensional molecular metals, describing normal-state properties, magnetic field effects, superconductivity, and the phenomena of interacting p and d electrons.

    15. Electric field gradients in metals

      International Nuclear Information System (INIS)

      Schatz, G.

      1979-01-01

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

    16. Metal chemistry of the transactinides

      International Nuclear Information System (INIS)

      Eichler, B.

      2000-12-01

      The elements with atomic numbers between 104 and 116 are expected to behave as metals. Their interaction with metal surfaces is of uppermost importance both to design experimental separation procedures as well as for their chemical characterization. This interaction is quantified by the net adsorption enthalpy. The determination of the net adsorption enthalpy requires the calculation of the solution enthalpy of transactinides in the bulk-phases of the solid adsorbent metals. These solution enthalpies have been calculated with the Miedema-model. For that purpose the necessary parameters of the transactinides: the metal radius, the molar volume, the electronic density at the Wigner-Seitz-Cell boundary and the electronegativity (Miedema Scale) have been obtained on the basis of empirical correlations starting from the entropies of solid transactinides. These entropies were estimated by extrapolations as a function of atomic masses along the groups of the periodic table. The results of the calculations show a strong dependence on the cohesion energy of the solid adsorbent metals as well as on the solution enthalpies of transactinides in the bulk-phase of these metals. The enthalpies of segregation of transactinides from the metallic bulk-phases as the 'driving forces' of the surface enrichment process were calculated. The calculated data allow the selection of the best suitable materials for the gas phase transport as well as of the adsorbent metal for chromatographic separations, for sampling and for electrochemical deposition in experiments with the transactinides. (author)

    17. Machine for dismantling metal parts

      Energy Technology Data Exchange (ETDEWEB)

      Prokopov, O.I.; Loginovskiy, V.I.; Yagudin, S.Z.

      1982-01-01

      The purpose of the invention is to reduce the outlays of time for dismantling metal parts under conditions of eliminating open gas and oil gushers in operational drilling. This goal is achieved because the machine for dismantling the metal parts is equipped with a set of clamping elements arranged on the chassis, where each of them has a drive.

    18. Heavy metal sorption by microalgae

      International Nuclear Information System (INIS)

      Sandau, E.; Sandau, P.; Pulz, O.

      1996-01-01

      Viable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small-scale cultivation tests (50 l) with Cd-resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died. Non-viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by-products changes only insignificantly. Their low price makes them economical. (orig.)

    19. Durability of metals from archaeological objects, metal meteorites, and native metals

      International Nuclear Information System (INIS)

      Johnson, A.B. Jr.; Francis, B.

      1980-01-01

      Metal durability is an important consideration in the multi-barrier nuclear waste storage concept. This study summarizes the ancient metals, the environments, and factors which appear to have contributed to metal longevity. Archaeological and radiochemical dating suggest that human use of metals began in the period 6000 to 7000 BC. Gold is clearly the most durable, but many objects fashioned from silver, copper, bronze, iron, lead, and tin have survived for several thousand years. Dry environments, such as tombs, appear to be optimum for metal preservation, but some metals have survived in shipwrecks for over a thousand years. The metal meteorites are Fe-base alloys with 5 to 60 wt% Ni and minor amounts of Co, I, and S. Some meteoritic masses with ages estimated to be 5,000 to 20,000 years have weathered very little, while other masses from the same meteorites are in advanced stages of weathering. Native metals are natural metallic ores. Approximately five million tonnes were mined from native copper deposits in Michigan. Copper masses from the Michigan deposits were transported by the Pleistocene glaciers. Areas on the copper surfaces which appear to represent glacial abrasion show minimal corrosion. Dry cooling tower technology has demonstrated that in pollution-free moist environments, metals fare better at temperatures above than below the dewpoint. Thus, in moderate temperature regimes, elevated temperatures may be useful rather than detrimental for exposures of metal to air. In liquid environments, relatively complex radiolysis reactions can occur, particularly where multiple species are present. A dry environment largely obviates radiolysis effects

    20. Durability of metals from archaeological objects, metal meteorites, and native metals

      Energy Technology Data Exchange (ETDEWEB)

      Johnson, A.B. Jr.; Francis, B.

      1980-01-01

      Metal durability is an important consideration in the multi-barrier nuclear waste storage concept. This study summarizes the ancient metals, the environments, and factors which appear to have contributed to metal longevity. Archaeological and radiochemical dating suggest that human use of metals began in the period 6000 to 7000 BC. Gold is clearly the most durable, but many objects fashioned from silver, copper, bronze, iron, lead, and tin have survived for several thousand years. Dry environments, such as tombs, appear to be optimum for metal preservation, but some metals have survived in shipwrecks for over a thousand years. The metal meteorites are Fe-base alloys with 5 to 60 wt% Ni and minor amounts of Co, I, and S. Some meteoritic masses with ages estimated to be 5,000 to 20,000 years have weathered very little, while other masses from the same meteorites are in advanced stages of weathering. Native metals are natural metallic ores. Approximately five million tonnes were mined from native copper deposits in Michigan. Copper masses from the Michigan deposits were transported by the Pleistocene glaciers. Areas on the copper surfaces which appear to represent glacial abrasion show minimal corrosion. Dry cooling tower technology has demonstrated that in pollution-free moist environments, metals fare better at temperatures above than below the dewpoint. Thus, in moderate temperature regimes, elevated temperatures may be useful rather than detrimental for exposures of metal to air. In liquid environments, relatively complex radiolysis reactions can occur, particularly where multiple species are present. A dry environment largely obviates radiolysis effects.

    1. Metal Contacts to Gallium Arsenide.

      Science.gov (United States)

      Ren, Fan

      1991-07-01

      While various high performance devices fabricated from the gallium arsenide (GaAs) and related materials have generated considerable interest, metallization are fundamental components to all semiconductor devices and integrated circuits. The essential roles of metallization systems are providing the desired electrical paths between the active region of the semiconductor and the external circuits through the metal interconnections and contacts. In this work, in-situ clean of native oxide, high temperature n-type, low temperature n-type and low temperature p-type ohmic metal systems have been studied. Argon ion mill was used to remove the native oxide prior to metal deposition. For high temperature process n-type GaAs ohmic contacts, Tungsten (W) and Tungsten Silicide (WSi) were used with an epitaxial grown graded Indium Gallium Arsenide (InGaAs) layer (0.2 eV) on GaAs. In addition, refractory metals, Molybdenum (Mo), was incorporated in the Gold-Germanium (AuGe) based on n-type GaAs ohmic contacts to replace conventional silver as barrier to prevent the reaction between ohmic metal and chlorine based plasma as well as the ohmic metallization intermixing which degrades the device performance. Finally, Indium/Gold-Beryllium (In/Au-Be) alloy has been developed as an ohmic contact for p-type GaAs to reduce the contact resistance. The Fermi-level pinning of GaAs has been dominated by the surface states. The Schottky barrier height of metal contacts are about 0.8 V regardless of the metal systems. By using p-n junction approach, barrier height of pulsed C-doped layers was achieved as high as 1.4 V. Arsenic implantation into GaAs method was also used to enhance the barrier height of 1.6 V.

    2. Metal artifact reduction method using metal streaks image subtraction

      International Nuclear Information System (INIS)

      Pua, Rizza D.; Cho, Seung Ryong

      2014-01-01

      Many studies have been dedicated for metal artifact reduction (MAR); however, the methods are successful to varying degrees depending on situations. Sinogram in-painting, filtering, iterative method are some of the major categories of MAR. Each has its own merits and weaknesses. A combination of these methods or hybrid methods have also been developed to make use of the different benefits of two techniques and minimize the unfavorable results. Our method focuses on the in-paitning approach and a hybrid MAR described by Xia et al. Although in-painting scheme is an effective technique in reducing the primary metal artifacts, a major drawback is the reintroduction of new artifacts that can be caused by an inaccurate interpolation process. Furthermore, combining the segmented metal image to the corrected nonmetal image in the final step of a conventional inpainting approach causes an issue of incorrect metal pixel values. Our proposed method begins with a sinogram in-painting approach and ends with an image-based metal artifact reduction scheme. This work provides a simple, yet effective solution for reducing metal artifacts and acquiring the original metal pixel information. The proposed method demonstrated its effectiveness in a simulation setting. The proposed method showed image quality that is comparable to the standard MAR; however, quantitatively more accurate than the standard MAR

    3. Do constructed wetlands remove metals or increase metal bioavailability?

      Science.gov (United States)

      Xu, Xiaoyu; Mills, Gary L

      2018-07-15

      The H-02 wetland was constructed to treat building process water and storm runoff water from the Tritium Processing Facility on the Department of Energy's Savannah River Site (Aiken, SC). Monthly monitoring of copper (Cu) and zinc (Zn) concentrations and water quality parameters in surface waters continued from 2014 to 2016. Metal speciation was modeled at each sampling occasion. Total Cu and Zn concentrations released to the effluent stream were below the NPDES limit, and the average removal efficiency was 65.9% for Cu and 71.1% for Zn. The metal-removal processes were found out to be seasonally regulated by sulfur cycling indicated by laboratory and model results. High temperature, adequate labile organic matter, and anaerobic conditions during the warm months (February to August) favored sulfate reduction that produced sulfide minerals to significantly remove metals. However, the dominant reaction in sulfur cycling shifted to sulfide oxidation during the cool months (September to next March). High concentrations of metal-organic complexes were observed, especially colloidal complexes of metal and fulvic acid (FA), demonstrating adsorption to organic matter became the primary process for metal removal. Meanwhile, the accumulation of metal-FA complexes in the wetland system will cause negative effects to the surrounding environment as they are biologically reactive, highly bioavailable, and can be easily taken up and transferred to ecosystems by trophic exchange. Copyright © 2018 Elsevier Ltd. All rights reserved.

    4. 21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

      Science.gov (United States)

      2010-04-01

      ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Knee joint patellofemorotibial polymer/metal/metal... § 888.3550 Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis. (a) Identification. A knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis is a device...

    5. Metal Matrix Composite Material by Direct Metal Deposition

      Science.gov (United States)

      Novichenko, D.; Marants, A.; Thivillon, L.; Bertrand, P. H.; Smurov, I.

      Direct Metal Deposition (DMD) is a laser cladding process for producing a protective coating on the surface of a metallic part or manufacturing layer-by-layer parts in a single-step process. The objective of this work is to demonstrate the possibility to create carbide-reinforced metal matrix composite objects. Powders of steel 16NCD13 with different volume contents of titanium carbide are tested. On the base of statistical analysis, a laser cladding processing map is constructed. Relationships between the different content of titanium carbide in a powder mixture and the material microstructure are found. Mechanism of formation of various precipitated titanium carbides is investigated.

    6. Alkali metal and alkali earth metal gadolinium halide scintillators

      Science.gov (United States)

      Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

      2016-08-02

      The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

    7. Deposition of metal Islands, metal clusters and metal containing single molecules on self-assembled monolayers

      NARCIS (Netherlands)

      Speets, Emiel Adrianus

      2005-01-01

      The central topic of this thesis is the deposition of metals on Self-Assembled Monolayers (SAMs). Metals are deposited in the form of submicron scale islands, nanometer scale clusters, and as supramolecular, organometallic coordination cages. Several SAMs on various substrates were prepared and

    8. Mycobacteria, Metals, and the Macrophage

      Science.gov (United States)

      Niederweis, Michael; Wolschendorf, Frank; Mitra, Avishek; Neyrolles, Olivier

      2015-01-01

      Summary Mycobacterium tuberculosis is a facultative intracellular pathogen that thrives inside host macrophages. A key trait of M. tuberculosis is to exploit and manipulate metal cation trafficking inside infected macrophages to ensure survival and replication inside the phagosome. Here we describe the recent fascinating discoveries that the mammalian immune system responds to infections with M. tuberculosis by overloading the phagosome with copper and zinc, two metals which are essential nutrients in small quantities but are toxic in excess. M. tuberculosis has developed multi-faceted resistance mechanisms to protect itself from metal toxicity including control of uptake, sequestration inside the cell, oxidation, and efflux. The host response to infections combines this metal poisoning strategy with nutritional immunity mechanisms that deprive M. tuberculosis from metals such as iron and manganese to prevent bacterial replication. Both immune mechanisms rely on the translocation of metal transporter proteins to the phagosomal membrane during the maturation process of the phagosome. This review summarizes these recent findings and discusses how metal-targeted approaches might complement existing TB chemotherapeutic regimens with novel anti-infective therapies. PMID:25703564

    9. Electronic structure of metal clusters

      International Nuclear Information System (INIS)

      Wertheim, G.K.

      1989-01-01

      Photoemission spectra of valence electrons in metal clusters, together with threshold ionization potential measurements, provide a coherent picture of the development of the electronic structure from the isolated atom to the large metallic cluster. An insulator-metal transition occurs at an intermediate cluster size, which serves to define the boundary between small and large clusters. Although the outer electrons may be delocalized over the entire cluster, a small cluster remains insulating until the density of states near the Fermi level exceeds 1/kT. In large clusters, with increasing cluster size, the band structure approaches that of the bulk metal. However, the bands remain significantly narrowed even in a 1000-atom cluster, giving an indication of the importance of long-range order. The core-electron binding-energy shifts of supported metal clusters depend on changes in the band structure in the initial state, as well as on various final-state effects, including changes in core hole screening and the coulomb energy of the final-state charge. For cluster supported on amorphous carbon, this macroscopic coulomb shift is often dominant, as evidenced by the parallel shifts of the core-electron binding energy and the Fermi edge. Auger data confirm that final-state effects dominate in cluster of Sn and some other metals. Surface atom core-level shifts provide a valuable guide to the contributions of initial-state changes in band structure to cluster core-electron binding energy shifts, especially for Au and Pt. The available data indicate that the shift observed in supported, metallic clusters arise largely from the charge left on the cluster by photoemission. As the metal-insulator transition is approached from above, metallic screening is suppressed and the shift is determined by the local environment. (orig.)

    10. Production of metal particles and clusters

      Science.gov (United States)

      Mcmanus, S. P.

      1982-01-01

      The feasibility of producing novel metals or metal clusters in a low gravity environment was studied. The production of coordinately unsaturated metal carbonyls by thermolysis or photolysis of stable metal carbonyls has the potential to generate novel catalysts by this technique. Laser irradiation of available metal carbonyls was investigated. It is found that laser induced decomposition of metal carbonyls is feasible for producing a variety of coordinately unsaturated species. Formation of clustered species does occur but is hampered by weak metal-metal bonds.

    11. Toxicity of heavy metals in the environment

      National Research Council Canada - National Science Library

      Oehme, F.W

      1978-01-01

      ... as the fundamental mechanisms of toxicity resulting from heavy metal chemicals. The more common toxic heavy metals, along with their biochemistry and associated clinical syndromes, are then described...

    12. Electroplastic effect in metals

      International Nuclear Information System (INIS)

      Sprecher, A.F. Jr.

      1984-01-01

      This report presents the effects of single d-c current pulses (1000-6000 A/mm 2 approx.60 μs) on plastically deforming metals. Polycrystalline wire specimens (D 0 approx. 1/2 mm, L 0 approx. 50 mm) representing the three more common crystal structures were employed: Ti from the HCP structures; Fe, Nb, and W from the bcc structure; and Al, Cu, and Ni from the fcc structure. The tests were carried out under uniaxial tension with an applied strain rate of 1.7 x 10 -4 sec -1 at room temperature. Forced air cooling was employed in order to reduce the principal side effect, heating. As a result of applying a current pulse, there were significant drops in the flow stress (1-35%). These drops not only included an electron dislocation interaction but all side effects as well. The main side effect due to the temperature rise was thermal expansion and could account for 60-90% of the drops. In addition to thermal expansion, some thermally induced plastic flow occurred as indicated by computer simulations. The total side effects (thermal expansion and plastic flow) approximately accounted for the stress drops in Ti, W, and Nb. However, a strong electron dislocation (ed) interaction was observed in Cu and Al since plastic flow from thermal effects was negligible. In Ni and Fe the portion of the stress drops due to (ed) was unclear due to some dynamic aging effects present

    13. Chemical decontamination of metals

      International Nuclear Information System (INIS)

      Partridge, J.A.; Lerch, R.E.

      1979-10-01

      A metal decontamination process based upon removal of contamination by treatment with a cerium (IV)-nitric acid solution (or other redox agent in nitric acid) is feasible and highly promising. The technique is effective in dissolving the surface layer of stainless steel. Dissolution rates of approximately 1.5 mils/h were demonstrated with cerium (IV)-nitric acid solutions. Removal of plutonium contamination from stainless steel was demonstrated in laboratory tests, in which activity levels were reduced from greater than 5 x 10 5 counts per minute to nondetectable levels in approximately one hour at 90 0 C. Removal of paint from stainless steel surfaces was also demonstrated. Advantages of this process over other chemical solutions include: (1) The solutions are not high salt systems; therefore, there is potentially less waste generated. (2) Cerium(IV) in nitric acid is a good dissolution agent for plutonium oxide. (3) Regeneration of Ce(IV) during the decontamination is accomplished by electrolysis. (4) The process should be effective for irregularly shaped equipment. (5) It could be effective as a spray or a flow-through system. 13 figures

    14. Hydriding of metallic thorium

      International Nuclear Information System (INIS)

      Miyake, Masanobu; Katsura, Masahiro; Matsuki, Yuichi; Uno, Masayoshi

      1983-01-01

      Powdered thorium is usually prepared through a combination of hydriding and dehydriding processes of metallic thorium in massive form, in which the hydriding process consists of two steps: the formation of ThH 2 , and the formation of Th 4 H 15 . However, little has yet been known as to on what stage of hydriding process the pulverization takes place. It is found in the present study that the formation of Th 4 H 15 by the reaction of ThH 2 with H 2 is responsible for pulverization. Temperature of 70 deg C adopted in this work for the reaction of formation Th 4 H 15 seems to be much more effective for production of powdered thorium than 200 - 300 deg C in the literature. The pressure-composition-temperature relationships for Th-H system are determined at 200, 300, 350, and 800 deg C. From these results, a tentative equilibrium phase diagram for the Th-H system is proposed, attention being focused on the two-phase region of ThH 2 and Th 4 H 15 . Pulverization process is discussed in terms of the tentative phase diagram. (author)

    15. Crystallochemistry of rhenium compounds with metal-metal bonds

      International Nuclear Information System (INIS)

      Koz'min, P.A.; Surazhskaya, M.D.

      1980-01-01

      A review is presented including a brief description of atomic structure of 59 coordination rhenium compounds with metal-metal bond. The most important bond lengths and valent angles are presented for each compound. The dependence of rhenium-rhenium bond length on its multiplicity is discussed and possible causes of deviations from this dependence (namely, axial ligand presence, steric repulsion of ligands) are considered. On the basis of qualitative comparison of electronegativity of ligands in dimer compounds with quarternary bond of rhenium-rhenium a supposition is made on the influence of formal charge of atomic group and summary electro-negativity of ligands on the possibility of the metal-metal bond formation

    16. Electrical Control of Metallic Heavy-Metal-Ferromagnet Interfacial States

      Science.gov (United States)

      Bi, Chong; Sun, Congli; Xu, Meng; Newhouse-Illige, Ty; Voyles, Paul M.; Wang, Weigang

      2017-09-01

      Voltage-control effects provide an energy-efficient means of tailoring material properties, especially in highly integrated nanoscale devices. However, only insulating and semiconducting systems can be controlled so far. In metallic systems, there is no electric field due to electron screening effects and thus no such control effect exists. Here, we demonstrate that metallic systems can also be controlled electrically through ionic rather than electronic effects. In a Pt /Co structure, the control of the metallic Pt /Co interface can lead to unprecedented control effects on the magnetic properties of the entire structure. Consequently, the magnetization and perpendicular magnetic anisotropy of the Co layer can be independently manipulated to any desired state, the efficient spin toques can be enhanced about 3.5 times, and the switching current can be reduced about one order of magnitude. This ability to control a metallic system may be extended to control other physical phenomena.

    17. Fabrication and Microstructure of Metal-Metal Syntactic Foams

      National Research Council Canada - National Science Library

      Nadler, J

      1998-01-01

      .... The composite microstructure consists of thin-wall, hollow Fe-Cr stainless steel spheres cast in various metal matrices including aluminum alloys 6061, 7075, 413, magnesium alloy AZ31B, and unalloyed...

    18. Subsurface excitations in a metal

      DEFF Research Database (Denmark)

      Ray, M. P.; Lake, R. E.; Sosolik, C. E.

      2009-01-01

      We investigate internal hot carrier excitations in a Au thin film bombarded by hyperthermal and low energy alkali and noble gas ions. Excitations within the thin film of a metal-oxide-semiconductor device are measured revealing that ions whose velocities fall below the classical threshold given...... by the free-electron model of a metal still excite hot carriers. Excellent agreement between these results and a nonadiabatic model that accounts for the time-varying ion-surface interaction indicates that the measured excitations are due to semilocalized electrons near the metal surface....

    19. Metal working and dislocation structures

      DEFF Research Database (Denmark)

      Hansen, Niels

      2007-01-01

      Microstructural observations are presented for different metals deformed from low to high strain by both traditional and new metal working processes. It is shown that deformation induced dislocation structures can be interpreted and analyzed within a common framework of grain subdivision on a finer...... and finer scale down to the nanometer dimension, which can be reached at ultrahigh strains. It is demonstrated that classical materials science and engineering principles apply from the largest to the smallest structural scale but also that new and unexpected structures and properties characterize metals...

    20. LCA of metal nanomaterial production

      DEFF Research Database (Denmark)

      Miseljic, Mirko; Diaz, Elsa Gabriela Alvarado; Olsen, Stig Irving

      The use of engineered nanomaterials (ENMs) in commercial product has reached a new stage, where consumers in their daily life are frequently encountered with products containing this new material class. Metal and metal-oxide nanomaterials are among the most commonly used ENMs in products. Potential......(OH)2 applied as additives in polypropylene (PP), and the production of PP with conventional additives that provide similar properties as the ENMs. Different scenarios of nanoproducts consisting of metal ENMs and PP were compared with current use of additives in PP products through a detailed cradle...

    1. Are Vicinal Metal Surfaces Stable?

      DEFF Research Database (Denmark)

      Frenken, J. W. M.; Stoltze, Per

      1999-01-01

      We use effective medium theory to demonstrate that the energies of many metal surfaces are lowered when these surfaces are replaced by facets with lower-index orientations. This implies that the low-temperature equilibrium shapes of many metal crystals should be heavily faceted. The predicted...... instability of vicinal metal surfaces is at variance with the almost generally observed stability of these surfaces. We argue that the unstable orientations undergo a defaceting transition at relatively low temperatures, driven by the high vibrational entropy of steps....

    2. Hydrogen permeation through metallic foils

      International Nuclear Information System (INIS)

      Bernardi, M.I.B.; Rodrigues, J.A.

      1987-01-01

      The process of electrolytic permeation of hydrogen through metallic foils is studied. A double electrolytic cell, in glass, in which the two compartments of reaction are separated by a metallic foil to be studied, was built. As direct result, the hydrogen diffusion coefficient in the metal is obtained. The hydrogen diffusion coefficients in the palladium and, in austenitic stainless steels 304 and 304 L, used in the Angra-1 reactor, were obtained. Samples of stainless steels with and without welding, were used. (Author) [pt

    3. Nanodisturbances in deformed Gum Metal

      International Nuclear Information System (INIS)

      Gutkin, Mikhail Yu.; Ishizaki, Toshitaka; Kuramoto, Shigeru; Ovid'ko, Ilya A.

      2006-01-01

      Systematic experiments have been performed to characterize defect structures in deformed Gum Metal, a special titanium alloy with high strength, low Young's modulus, excellent cold workability and low resistance to shear in certain crystallographic planes. Results from high-resolution transmission electron microscopy characterization reveal nanodisturbances (planar nanoscopic areas of local shear) as typical elements of defect structures in deformed Gum Metal. A theoretical model is suggested describing nanodisturbances as nanoscale dipoles of non-conventional partial dislocations with arbitrary, non-quantized Burgers vectors. It is shown theoretically that the homogeneous generation of nanodisturbances is energetically favorable in Gum Metal, where they effectively carry plastic flow

    4. Reviewing metallic PEMFC bipolar plates

      Energy Technology Data Exchange (ETDEWEB)

      Wang, H.; Turner, J.A. [National Renewable Energy Laboratory, Golden, CO (United States)

      2010-08-15

      A bipolar plate is one of the most important components in a polymer exchange membrane fuel cell (PEMFC) stack and has multiple functions. Metallic bipolar plate candidates have advantages over composite rivals in excellent electrical and thermal conductivity, good mechanical strength, high chemical stability, very wide alloy choices, low cost and, most importantly, existing pathways for high-volume, high-speed mass production. The challenges with metallic bipolar plates are the higher contact resistance and possible corrosion products, which may contaminate the membrane electrode assembly. This review evaluates the candidate metallic and coating materials for bipolar plates and gives the perspective of the research trends. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

    5. Methods for synthesizing metal oxide nanowires

      Science.gov (United States)

      Sunkara, Mahendra Kumar; Kumar, Vivekanand; Kim, Jeong H.; Clark, Ezra Lee

      2016-08-09

      A method of synthesizing a metal oxide nanowire includes the steps of: combining an amount of a transition metal or a transition metal oxide with an amount of an alkali metal compound to produce a mixture; activating a plasma discharge reactor to create a plasma discharge; exposing the mixture to the plasma discharge for a first predetermined time period such that transition metal oxide nanowires are formed; contacting the transition metal oxide nanowires with an acid solution such that an alkali metal ion is exchanged for a hydrogen ion on each of the transition metal oxide nanowires; and exposing the transition metal oxide nanowires to the plasma discharge for a second predetermined time period to thermally anneal the transition metal oxide nanowires. Transition metal oxide nanowires produced using the synthesis methods described herein are also provided.

    6. Heavy Metal Stars

      Science.gov (United States)

      2001-08-01

      thereafter dies as a burnt-out, dim "white dwarf" . Stars with masses between 0.8 and 8 times that of the Sun are believed to evolve to AGB-stars and to end their lives in this particular way. At the same time, they produce beautiful nebulae like the "Dumbbell Nebula". Our Sun will also end its active life this way, probably some 7 billion years from now. Low-metallicity stars The detailed understanding of the "s-process" and, in particular, where it takes place inside an AGB-star, has been an area of active research for many years. Current state-of-the-art computer-based stellar models predict that the s-process should be particularly efficient in stars with a comparatively low content of metals ("metal-poor" or "low-metallicity" stars) . In such stars - which were born at an early epoch in our Galaxy and are therefore quite old - the "s-process" is expected to effectively produce atomic nuclei all the way up to the most heavy, stable ones, like Lead (atomic number 82 [2]) and Bismuth (atomic number 83) - since more neutrons are available per Iron-seed nucleus when there are fewer such nuclei (as compared to the solar composition). Once these elements have been produced, the addition of more s-process neutrons to those nuclei will only produce unstable elements that decay back to Lead. Hence, when the s-process is sufficiently efficient, atomic nuclei with atomic numbers around 82, that is, the Lead region, just continue to pile up. As a result, when compared to stars with "normal" abundances of the metals (like our Sun), those low-metallicity stars should thus exhibit a significant "over-abundance" of those very heavy elements with respect to Iron, in particular of Lead . Looking for Lead Direct observational support for this theoretical prediction would be the discovery of some low-metallicity stars with a high abundance of Lead. At the same time, the measured amounts of all the heavy elements and their relative abundances would provide very valuable information and

    7. Transition metal nuclear magnetic resonance

      International Nuclear Information System (INIS)

      Pregosin, P.S.

      1991-01-01

      Transition metal NMR spectroscopy has progressed enormously in recent years. New methods, and specifically solid-state methods and new pulse sequences, have allowed access to data from nuclei with relatively low receptivities with the result that chemists have begun to consider old and new problems, previously unapproachable. Moreover, theory, computational science in particular, now permits the calculation of not just 13 C, 15 N and other light nuclei chemical shifts, but heavy main-group element and transition metals as well. These two points, combined with increasing access to high field pulsed spectrometer has produced a wealth of new data on the NMR transition metals. A new series of articles concerned with measuring, understanding and using the nuclear magnetic resonance spectra of the metals of Group 3-12 is presented. (author)

    8. Pair potentials in liquid metals

      International Nuclear Information System (INIS)

      Faber, T.E.

      1980-01-01

      The argument which justifies the use of a pair potential to describe the structure-dependent term in the energy of liquid metals is briefly reviewed. Because there is an additional term in the energy which depends upon volume rather than structure, and because the pair potential itself is volume-dependent, the relationship between pair potential and observable properties such as pressure, bulk modulus and pair distribution function is more complicated for liquid metals than it is for molecular liquids. Perhaps for this reason, the agreement between pair potentials inferred from observable properties and pair potentials calculated by means of pseudo-potential theory is still far from complete. The pair potential concept is applicable only to simple liquid metals, in which the electron-ion interaction is weak. No attempt is made to discuss liquid transition and rare-earth metals, which are not simple in this sense. (author)

    9. Nanotoxicology of Metal Oxide Nanoparticles

      Directory of Open Access Journals (Sweden)

      Amedea B. Seabra

      2015-06-01

      Full Text Available This review discusses recent advances in the synthesis, characterization and toxicity of metal oxide nanoparticles obtained mainly through biogenic (green processes. The in vitro and in vivo toxicities of these oxides are discussed including a consideration of the factors important for safe use of these nanomaterials. The toxicities of different metal oxide nanoparticles are compared. The importance of biogenic synthesized metal oxide nanoparticles has been increasing in recent years; however, more studies aimed at better characterizing the potent toxicity of these nanoparticles are still necessary for nanosafely considerations and environmental perspectives. In this context, this review aims to inspire new research in the design of green approaches to obtain metal oxide nanoparticles for biomedical and technological applications and to highlight the critical need to fully investigate the nanotoxicity of these particles.

    10. Comparative analysis of metal samples

      International Nuclear Information System (INIS)

      Lopez M, J.; Ramirez T, J.J.; Sandoval J, A.R.; Villasenor S, P.; Aspiazu F, J.A.

      2001-01-01

      Metal wastes were analysed to establish its origin with respect to a set of pieces. The elemental analysis was realized using the PIXE technique (Proton induced X-ray emission). Results are presented. (Author)

    11. Metal-insulator-semiconductor photodetectors.

      Science.gov (United States)

      Lin, Chu-Hsuan; Liu, Chee Wee

      2010-01-01

      The major radiation of the sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

    12. Metal-Insulator-Semiconductor Photodetectors

      Directory of Open Access Journals (Sweden)

      Chu-Hsuan Lin

      2010-09-01

      Full Text Available The major radiation of the Sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

    13. Plasticity and creep of metals

      CERN Document Server

      Rusinko, Andrew

      2011-01-01

      Here is a systematic presentation of the postulates, theorems and principles of mathematical theories of plasticity and creep in metals, and their applications. Special attention is paid to analysis of the advantages and shortcomings of the classical theories.

    14. Experiments with activated metal foils

      Energy Technology Data Exchange (ETDEWEB)

      Malati, M A [Medway and Maidstone Coll. of Tech., Chatham (UK)

      1978-09-01

      Experiments based on the activation of metal foils by slow neutron bombardment which can be used to demonstrate various aspects of artificial radioactivity are described and discussed. Suitable neutron sources and foils are considered.

    15. Time domain electromagnetic metal detectors

      International Nuclear Information System (INIS)

      Hoekstra, P.

      1996-01-01

      This presentation focuses on illustrating by case histories the range of applications and limitations of time domain electromagnetic (TDEM) systems for buried metal detection. Advantages claimed for TDEM metal detectors are: independent of instrument response (Geonics EM61) to surrounding soil and rock type; simple anomaly shape; mitigation of interference by ambient electromagnetic noise; and responsive to both ferrous and non-ferrous metallic targets. The data in all case histories to be presented were acquired with the Geonics EM61 TDEM system. Case histories are a test bed site on Molokai, Hawaii; Fort Monroe, Virginia; and USDOE, Rocky Flats Plant. The present limitations of this technology are: discrimination capabilities in terms of type of ordnance, and depth of burial is limited, and ability of resolving targets with small metallic ambient needs to be improved

    16. Technique for joining metal tubing

      Science.gov (United States)

      Wright, H. W.

      1976-01-01

      Uniform wall thickness and uninterrupted heat transfer is achieved by using shaped metal insert as wall material for joint. Insert acts as support during brazing, after which excess material is ground away to bring joint to original tubing size.

    17. Machining of Metal Matrix Composites

      CERN Document Server

      2012-01-01

      Machining of Metal Matrix Composites provides the fundamentals and recent advances in the study of machining of metal matrix composites (MMCs). Each chapter is written by an international expert in this important field of research. Machining of Metal Matrix Composites gives the reader information on machining of MMCs with a special emphasis on aluminium matrix composites. Chapter 1 provides the mechanics and modelling of chip formation for traditional machining processes. Chapter 2 is dedicated to surface integrity when machining MMCs. Chapter 3 describes the machinability aspects of MMCs. Chapter 4 contains information on traditional machining processes and Chapter 5 is dedicated to the grinding of MMCs. Chapter 6 describes the dry cutting of MMCs with SiC particulate reinforcement. Finally, Chapter 7 is dedicated to computational methods and optimization in the machining of MMCs. Machining of Metal Matrix Composites can serve as a useful reference for academics, manufacturing and materials researchers, manu...

    18. Phonon scattering in metallic glasses

      International Nuclear Information System (INIS)

      Black, J.L.

      1979-01-01

      The purpose of this article is to review some recent theoretical and experimental developments in the study of metallic glasses at temperatures near or below 1K. In this temperature regime, it appears that practically all glasses, whether metallic or insulating, behave in a similar fashion. The fact that such similarities occur, despite substantial structural differences between metallic and insulating glasses, constitutes a major theoretical challenge. This challenge, however, is not directly addressed in what follows. Instead, the evidence for universal behavior and the theory which is necessary to understand this evidence are emphasized. It turns out that most of this evidence involves a comparison of phonon scattering in metallic glasses with its counterpart in insulating glasses

    19. Moving Belt Metal Detector (MBMD)

      National Research Council Canada - National Science Library

      Nelson, Carl V; Mendat, Deborah P; Huynh, Toan B

      2006-01-01

      The Johns Hopkins University Applied Physics Laboratory (JHU/APL) has developed a prototype metal detection survey system that will increase the search speed of conventional technology while maintaining high sensitivity...

    20. Organometallic chemistry of metal surfaces

      International Nuclear Information System (INIS)

      Muetterties, E.L.

      1981-06-01

      The organometallic chemistry of metal surfaces is defined as a function of surface crystallography and of surface composition for a set of cyclic hydrocarbons that include benzene, toluene, cyclohexadienes, cyclohexene, cyclohexane, cyclooctatetraene, cyclooctadienes, cyclooctadiene, cycloheptatriene and cyclobutane. 12 figures

    1. Positron annihilation in superconductive metals

      Energy Technology Data Exchange (ETDEWEB)

      Dekhtjar, I.J.

      1969-03-10

      A correlation is shown between the parameters of superconductive metals and those of positron annihilation. Particular attention is paid to the density states obtained from the electron specific heat.

    2. Metal investigation of beams durable

      Directory of Open Access Journals (Sweden)

      Ya.A. Balabukh

      2011-12-01

      Full Text Available Results of metal researches of long-term storage beams are considered. It is determined that the steel of beams meets the requirements of Norms. Their acceptability for construction of bridges is established.

    3. Selenophene transition metal complexes

      Energy Technology Data Exchange (ETDEWEB)

      White, Carter James [Iowa State Univ., Ames, IA (United States)

      1994-07-27

      This research shows that selenophene transition metal complexes have a chemistry that is similar to their thiophene analogs. Selenophene coordination has been demonstrated and confirmed by molecular structure in both the η5- and the η1(Se)-coordination modes. The reaction chemistry of selenophene complexes closely resembles that of the analogous thiophene complexes. One major difference, however, is that selenophene is a better donor ligand than thiophene making the selenophene complexes more stable than the corresponding thiophene complexes. The 77Se NMR chemical shift values for selenophene complexes fall within distinct regions primarily depending on the coordination mode of the selenophene ligand. In the final paper, the C-H bond activation of η1(S)-bound thiophenes, η1(S)-benzothiophene and η1(Se)-bound selenophenes has been demonstrated. The deprotonation and rearrangement of the η1(E)-bound ligand to the carbon bound L-yl complex readily occurs in the presence of base. Reprotonation with a strong acid gives a carbene complex that is unreactive towards nucleophilic attack at the carbene carbon and is stable towards exposure to air. The molecular structure of [Cp(NO)(PPh3)Re(2-benzothioenylcarbene)]O3SCF3 was determined and contains a Re-C bond with substantial double bond character. Methyl substitution for the thienylcarbene or selenylcarbene gives a carbene that rearranges thermally to give back the η1(E)-bound complex. Based on these model reactions, a new mechanism for the H/D exchange of thiophene over the hydrodesulfurization catalyst has been proposed.

    4. Electrode for disintegrating metallic material

      International Nuclear Information System (INIS)

      Persang, J.C.

      1985-01-01

      A graphite electrode is provided for disintegrating and removing metallic material from a workpiece, e.g., such as portions of a nuclear reactor to be repaired while in an underwater and/or radioactive environment. The electrode is provided with a plurality of openings extending outwardly, and a manifold for supplying a mixture of water and compressed gas to be discharged through the openings for sweeping away the disintegrated metallic material during use of the electrode

    5. Actively convected liquid metal divertor

      International Nuclear Information System (INIS)

      Shimada, Michiya; Hirooka, Yoshi

      2014-01-01

      The use of actively convected liquid metals with j × B force is proposed to facilitate heat handling by the divertor, a challenging issue associated with magnetic fusion experiments such as ITER. This issue will be aggravated even more for DEMO and power reactors because the divertor heat load will be significantly higher and yet the use of copper would not be allowed as the heat sink material. Instead, reduced activation ferritic/martensitic steel alloys with heat conductivities substantially lower than that of copper, will be used as the structural materials. The present proposal is to fill the lower part of the vacuum vessel with liquid metals with relatively low melting points and low chemical activities including Ga and Sn. The divertor modules, equipped with electrodes and cooling tubes, are immersed in the liquid metal. The electrode, placed in the middle of the liquid metal, can be biased positively or negatively with respect to the module. The j × B force due to the current between the electrode and the module provides a rotating motion for the liquid metal around the electrodes. The rise in liquid temperature at the separatrix hit point can be maintained at acceptable levels from the operation point of view. As the rotation speed increases, the current in the liquid metal is expected to decrease due to the v × B electromotive force. This rotating motion in the poloidal plane will reduce the divertor heat load significantly. Another important benefit of the convected liquid metal divertor is the fast recovery from unmitigated disruptions. Also, the liquid metal divertor concept eliminates the erosion problem. (letter)

    6. Chain formation of metal atoms

      DEFF Research Database (Denmark)

      Bahn, Sune Rastad; Jacobsen, Karsten Wedel

      2001-01-01

      The possibility of formation of single-atomic chains by manipulation of nanocontacts is studied for a selection of metals (Ni, Pd, Pt, Cu, Ag, Au). Molecular dynamics simulations show that the tendency for chain formation is strongest for Au and Pt. Density functional theory calculations indicate...... that the metals which form chains exhibit pronounced many-atom interactions with strong bonding in low coordinated systems....

    7. Metallizing of machinable glass ceramic

      International Nuclear Information System (INIS)

      Seigal, P.K.

      1976-02-01

      A satisfactory technique has been developed for metallizing Corning (Code 9658) machinable glass ceramic for brazing. Analyses of several bonding materials suitable for metallizing were made using microprobe analysis, optical metallography, and tensile strength tests. The effect of different cleaning techniques on the microstructure and the effect of various firing temperatures on the bonding interface were also investigated. A nickel paste, used for thick-film application, has been applied to obtain braze joints with strength in excess of 2000 psi

    8. Rare earth metal alloy magnets

      International Nuclear Information System (INIS)

      Harris, I.R.; Evans, J.M.; Nyholm, P.S.

      1979-01-01

      This invention relates to rare earth metal alloy magnets and to methods for their production. The technique is based on the fact that rare earth metal alloys (for e.g. cerium or yttrium) which have been crumbled to form a powder by hydride formation and decomposition can be used for the fabrication of magnets without the disadvantages inherent in alloy particle size reduction by mechanical milling. (UK)

    9. Nanostructures via DNA scaffold metallization

      OpenAIRE

      Ning, C.; Zinchenko, A.; Baigl, D.; Pyshkina, O.; Sergeyev, V.; Endo, Kazunaka; Yoshikawa, K.

      2005-01-01

      The critical role of polymers in process of noble metals nanostructures formation is well known, however, the use of DNA chain template in this process is yet largely unknown. In this study we demonstrate different ways of silver deposition on DNA template and report the influence of silver nanostructures formation on DNA conformational state. Metallization of DNA chain proceeds by two different scenarios depending on DNA conformation. If DNA chain is unfolded (elongated) chain, silver reduct...

    10. 3D printing with metals

      OpenAIRE

      Ribeiro, António Fernando

      1998-01-01

      Rapid Prototyping is a recently developed technique that ‘prints’ a component, instead of manufacturing it in traditional terms, by using materials ranging from photopolymers to thermoplastics, including paper. Since these materials are in most cases not suitable for assessement purposes a new approach has been created. It has similar ‘build up’ technique but uses metal as raw material. The process entails the use of a gas metal arc fusion welding robot which deposits successive layers of met...

    11. Experiments on sheet metal shearing

      OpenAIRE

      Gustafsson, Emil

      2013-01-01

      Within the sheet metal industry, different shear cutting technologies are commonly used in several processing steps, e.g. in cut to length lines, slitting lines, end cropping etc. Shearing has speed and cost advantages over competing cutting methods like laser and plasma cutting, but involves large forces on the equipment and large strains in the sheet material.Numerical models to predict forces and sheared edge geometry for different sheet metal grades and different shear parameter set-ups a...

    12. LIQUID METAL COMPOSITIONS CONTAINING URANIUM

      Science.gov (United States)

      Teitel, R.J.

      1959-04-21

      Liquid metal compositions containing a solid uranium compound dispersed therein is described. Uranium combines with tin to form the intermetallic compound USn/sub 3/. It has been found that this compound may be incorporated into a liquid bath containing bismuth and lead-bismuth components, if a relatively small percentage of tin is also included in the bath. The composition has a low thermal neutron cross section which makes it suitable for use in a liquid metal fueled nuclear reactor.

    13. METHOD OF DISSOLVING URANIUM METAL

      Science.gov (United States)

      Slotin, L.A.

      1958-02-18

      This patent relates to an economicai means of dissolving metallic uranium. It has been found that the addition of a small amount of perchloric acid to the concentrated nitric acid in which the uranium is being dissolved greatly shortens the time necessary for dissolution of the metal. Thus the use of about 1 or 2 percent of perchioric acid based on the weight of the nitric acid used, reduces the time of dissolution of uranium by a factor of about 100.

    14. PRETREATING URANIUM FOR METAL PLATING

      Science.gov (United States)

      Wehrmann, R.F.

      1961-05-01

      A process is given for anodically treating the surface of uranium articles, prior to metal plating. The metal is electrolyzed in an aqueous solution of about 10% polycarboxylic acid, preferably oxalic acid, from 1 to 5% by weight of glycerine and from 1 to 5% by weight of hydrochloric acid at from 20 to 75 deg C for from 30 seconds to 15 minutes. A current density of from 60 to 100 amperes per square foot is used.

    15. Metal detector technology data base

      Energy Technology Data Exchange (ETDEWEB)

      Porter, L.K.; Gallo, L.R.; Murray, D.W.

      1990-08-01

      The tests described in this report were conducted to obtain information on the effects target characteristics have on portal type metal detector response. A second purpose of the tests was to determine the effect of detector type and settings on the detection of the targets. Although in some cases comparison performance of different types and makes of metal detectors is found herein, that is not the primary purpose of the report. Further, because of the many variables that affect metal detector performance, the information presented can be used only in a general way. The results of these tests can show general trends in metal detection, but do little for making accurate predictions as to metal detector response to a target with a complex shape such as a handgun. The shape of an object and its specific metal content (both type and treatment) can have a significant influence on detection. Thus it should not be surprising that levels of detection for a small 100g stainless steel handgun are considerably different than for detection of the 100g stainless steel right circular cylinder that was used in these tests. 7 figs., 1 tab.

    16. Titanium metal: extraction to application

      Energy Technology Data Exchange (ETDEWEB)

      Gambogi, Joseph (USGS, Reston, VA); Gerdemann, Stephen J.

      2002-09-01

      In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

    17. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

      International Nuclear Information System (INIS)

      Richard T. Scalettar; Warren E. Pickett

      2005-01-01

      This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals

    18. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

      Energy Technology Data Exchange (ETDEWEB)

      Scalettar, Richard T.; Pickett, Warren E.

      2004-07-01

      This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals.

    19. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

      Energy Technology Data Exchange (ETDEWEB)

      Richard T. Scalettar; Warren E. Pickett

      2005-08-02

      This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (i) Mott transitions in transition metal oxides, (ii) magnetism in half-metallic compounds, and (iii) large volume-collapse transitions in f-band metals.

    20. Metal nanoparticles as a conductive catalyst

      Science.gov (United States)

      Coker, Eric N [Albuquerque, NM

      2010-08-03

      A metal nanocluster composite material for use as a conductive catalyst. The metal nanocluster composite material has metal nanoclusters on a carbon substrate formed within a porous zeolitic material, forming stable metal nanoclusters with a size distribution between 0.6-10 nm and, more particularly, nanoclusters with a size distribution in a range as low as 0.6-0.9 nm.

    1. Metal sponge for cryosorption pumping applications

      International Nuclear Information System (INIS)

      Myneni, G.R.; Kneisel, P.

      1995-01-01

      A system has been developed for adsorbing gases at high vacuum in a closed area. The system utilizes large surface clean anodized metal surfaces at low temperatures to adsorb the gases. The large surface clean anodized metal is referred to as a metal sponge. The metal sponge generates or maintains the high vacuum by increasing the available active cryosorbing surface area. 4 figs

    2. The 'Invisible' Metal Particles in Catalysis

      NARCIS (Netherlands)

      Koningsberger, D.C.; Diaz-Moreno, S.; Muñoz-Paez, A.

      1997-01-01

      An easy, reliable and straightforward method to determine the sizes of small metal particles in supported metal catalyst which are invisible for most techniques (chemisorption, XRD, HRTEM) is presented. The technique we consider more appropriate is EXAFS, because it detects metal metal bonds even

    3. Formation of extremely narrow metallic lines

      International Nuclear Information System (INIS)

      Harris, E.P.; Keyes, R.W.

      1979-01-01

      A method for forming metal lines, particularly lines which are superconductive, involves delineating a pattern on a thin metal film on a substrate by masking techniques, ion implanting the metal film to a desired depth, removing the mask and etching away the unimplanted portion of the metal film to leave the line whose width is equal to the implanted depth. (U.K.)

    4. Heavy metals precipitation in sewage sludge

      NARCIS (Netherlands)

      Marchioretto, M.M.; Rulkens, W.H.; Bruning, H.

      2005-01-01

      There is a great need for heavy metal removal from strongly metal-polluted sewage sludges. One of the advantages of heavy metal removal from this type of sludge is the possibility of the sludge disposal to landfill with reduced risk of metals being leached to the surface and groundwater. Another

    5. Shocked plate metal atom oxidation laser

      International Nuclear Information System (INIS)

      De Koker, J.G.; Rice, W.W. Jr.; Jensen, R.J.

      1975-01-01

      A method and apparatus for producing metal atom oxidation lasing wherein an explosively shocked grooved metal plate produces metal vapor jets directed through an appropriate gaseous oxidizer are described. Reaction of the metal vapor with the oxidizer produces molecular species having a population inversion therein. (U.S.)

    6. Rare-earth metal transition metal borocarbide and nitridoborate superconductors

      Energy Technology Data Exchange (ETDEWEB)

      Niewa, Rainer; Shlyk, Larysa; Blaschkowski, Bjoern [Stuttgart Univ. (Germany). Inst. fuer Anorganische Chemie

      2011-07-01

      Few years after the discovery of superconductivity in high-T{sub c} cuprates, borocarbides and shortly after nitridoborates with reasonably high T{sub c}s up to about 23 K attracted considerable attention. Particularly for the rare-earth metal series with composition RNi{sub 2}[B{sub 2}C] it turned out, that several members exhibit superconductivity next to magnetic order with both T{sub c} above or below the magnetic ordering temperature. Therefore, these compounds have been regarded as ideal materials to study the interplay and coexistence of superconductivity and long range magnetic order, due to their comparably high ordering temperatures and similar magnetic and superconducting condensation energies. This review gathers information on the series RNi{sub 2}[B{sub 2}C] and isostructural compounds with different transition metals substituting Ni as well as related series like RM[BC], RM[BN], AM[BN] and R{sub 3}M{sub 2}[BN]{sub 2}N (all with R = rare-earth metal, A = alkaline-earth metal, M = transition metal) with special focus on synthesis, crystal structures and structural trends in correspondence to physical properties. (orig.)

    7. Optical transmission theory for metal-insulator-metal periodic nanostructures

      Directory of Open Access Journals (Sweden)

      Blanchard-Dionne Andre-Pierre

      2016-11-01

      Full Text Available A semi-analytical formalism for the optical properties of a metal-insulator-metal periodic nanostructure using coupled-mode theory is presented. This structure consists in a dielectric layer in between two metallic layers with periodic one-dimensional nanoslit corrugation. The model is developed using multiple-scattering formalism, which defines transmission and reflection coefficients for each of the interface as a semi-infinite medium. Total transmission is then calculated using a summation of the multiple paths of light inside the structure. This method allows finding an exact solution for the transmission problem in every dimension regime, as long as a sufficient number of diffraction orders and guided modes are considered for the structure. The resonant modes of the structure are found to be related to the metallic slab only and to a combination of both the metallic slab and dielectric layer. This model also allows describing the resonant behavior of the system in the limit of a small dielectric layer, for which discontinuities in the dispersion curves are found. These discontinuities result from the out-of-phase interference of the different diffraction orders of the system, which account for field interaction for both inner interfaces of the structure.

    8. Inert anode containing base metal and noble metal useful for the electrolytic production of aluminum

      Science.gov (United States)

      Ray, Siba P.; Liu, Xinghua

      2000-01-01

      An inert anode for production of metals such as aluminum is disclosed. The inert anode comprises a base metal selected from Cu and Ag, and at least one noble metal selected from Ag, Pd, Pt, Au, Rh, Ru, Ir and Os. The inert anode may optionally be formed of sintered particles having interior portions containing more base metal than noble metal and exterior portions containing more noble metal than base metal. In a preferred embodiment, the base metal comprises Cu, and the noble metal comprises Ag, Pd or a combination thereof.

    9. Role of Bioadsorbents in Reducing Toxic Metals

      OpenAIRE

      Mathew, Blessy Baby; Jaishankar, Monisha; Biju, Vinai George; Krishnamurthy Nideghatta Beeregowda

      2016-01-01

      Industrialization and urbanization have led to the release of increasing amounts of heavy metals into the environment. Metal ion contamination of drinking water and waste water is a serious ongoing problem especially with high toxic metals such as lead and cadmium and less toxic metals such as copper and zinc. Several biological materials have attracted many researchers and scientists as they offer both cheap and effective removal of heavy metals from waste water. Therefore it is urgent to st...

    10. Carbide-reinforced metal matrix composite by direct metal deposition

      Science.gov (United States)

      Novichenko, D.; Thivillon, L.; Bertrand, Ph.; Smurov, I.

      Direct metal deposition (DMD) is an automated 3D laser cladding technology with co-axial powder injection for industrial applications. The actual objective is to demonstrate the possibility to produce metal matrix composite objects in a single-step process. Powders of Fe-based alloy (16NCD13) and titanium carbide (TiC) are premixed before cladding. Volume content of the carbide-reinforced phase is varied. Relationships between the main laser cladding parameters and the geometry of the built-up objects (single track, 2D coating) are discussed. On the base of parametric study, a laser cladding process map for the deposition of individual tracks was established. Microstructure and composition of the laser-fabricated metal matrix composite objects are examined. Two different types of structures: (a) with the presence of undissolved and (b) precipitated titanium carbides are observed. Mechanism of formation of diverse precipitated titanium carbides is studied.

    11. INEL metal recycle radioactive scrap metal survey report

      International Nuclear Information System (INIS)

      Funk, D.M.

      1994-09-01

      DOE requested that inventory and characterization of radioactive scrap metal (RSM) be conducted across the DOE complex. Past studies have estimated the metal available from unsubstantiated sources. In meetings held in FY-1993, with seven DOE sites represented and several DOE-HQ personnel present, INEL personnel discovered that these numbers were not reliable and that large stockpiles did not exist. INEL proposed doing in-field measurements to ascertain the amount of RSM actually available. This information was necessary to determine the economic viability of recycling and to identify feed stock that could be used to produce containers for radioactive waste. This inventory measured the amount of RSM available at the selected DOE sites. Information gathered included radionuclide content and chemical form, general radiation field, alloy type, and mass of metal

    12. THE METAL CARBONYLS.

      Science.gov (United States)

      Blanchard, A A

      1941-10-03

      When the metal carbonyls were first discovered, their properties were startling because they seemed to violate nearly all the previously recognized generalizations of chemistry. Even to-day the existence of the carbonyls is not particularly emphasized in elementary courses of chemistry because it is rather hard to reconcile them with the first presentations of the generalizations of chemistry. Nevertheless, as the student progresses deeper into the knowledge of chemistry it becomes desirable to include the knowledge of the carbonyls both because they become more comprehensible when viewed in the light of Werner's system of coordination and because they themselves contribute to the comprehension of the Werner theory. As long ago as 1931, Reiff in his discussion of cobalt nitrosyl carbonyl recognized the correlation between the effective atomic number and the volatility of carbonyls. A more recent study of charged Werner coordination complexes, that is, of complex ions, has shown a similar role of the effective atomic number. We are standing on fairly firm ground when we point out the correlation between E.A.N. and the volatility of the carbonyl complexes and the existence of complex ions. Be it noted that we have made no postulates as to the arrangement of the electrons in quantum levels. In the inert gases the outer principal quantum group is supposed always to contain eight electrons. In the carbonyls and other Werner complexes there is no compelling reason to suppose that the electrons in the coordinating layer, be this layer of eight, ten, twelve or sixteen electrons, are not all at the same energy level. Although we have confined our discussion almost exclusively to the property of volatility, the carbonyls are very interesting from the standpoint of several other properties, for example, magnetic susceptibility and dielectric constant. Enthusiasts in the interpretation of such properties try to draw conclusions as to the condition of the electrons, sometimes

    13. Trace metal speciation: Finally, correctly addressing trace metal issues

      International Nuclear Information System (INIS)

      Donard, O.F.X.

      2001-01-01

      The history of the development of trace metal speciation was discussed and the reasons behind the relatively slow widespread acceptance of its importance were presented. Partially, this was due to the lack of availability of commercial instrumentation and partly to the drive towards improving sensitivity in analytical chemistry which had focused attention on total concentration determinations. The sophistication and control of analytical instrumentation is now such that the spotlight must be turned onto the chemical species of an element present in a sample since this is what governs its behaviour in the biosphere. Indeed, several companies are currently considering the introduction of instrumentation specifically designed for metal species determination

    14. Metal induced gap states at alkali halide/metal interface

      International Nuclear Information System (INIS)

      Kiguchi, Manabu; Yoshikawa, Genki; Ikeda, Susumu; Saiki, Koichiro

      2004-01-01

      The electronic state of a KCl/Cu(0 0 1) interface was investigated using the Cl K-edge near-edge X-ray absorption fine structure (NEXAFS). A pre-peak observed on the bulk edge onset of thin KCl films has a similar feature to the peak at a LiCl/Cu(0 0 1) interface, which originates from the metal induced gap state (MIGS). The present result indicates that the MIGS is formed universally at alkali halide/metal interfaces. The decay length of MIGS to an insulator differs from each other, mainly due to the difference in the band gap energy of alkali halide

    15. Metal Compression Forming of aluminum alloys and metal matrix composites

      Energy Technology Data Exchange (ETDEWEB)

      Viswanathan, S.; Ren, W.; Porter, W.D.; Brinkman, C.R.; Sabau, A.S.; Purgert, R.M.

      2000-02-01

      Metal Compression Forming (MCF) is a variant of the squeeze casting process, in which molten metal is allowed to solidify under pressure in order to close porosity and form a sound part. However, the MCF process applies pressure on the entire mold face, thereby directing pressure on all regions of the casting and producing a uniformly sound part. The process is capable of producing parts with properties close to those of forgings, while retaining the near net shape, complexity in geometry, and relatively low cost of the casting process.

    16. Decontamination method of contaminated metals

      International Nuclear Information System (INIS)

      Kawamura, Fumio; Ueda, Yoshihiro; Sato, Chikara; Komori, Itaru.

      1980-01-01

      Purpose: To effectively separate radioactive materials from molten metals in dry-processing method by heating metals contaminated with radioactive materials at a temperature below melting point to oxidize the surface thereof, then heating them to melt and include the radioactive materials into the oxides. Method: Metals contaminated with radioactive materials are heated at a temperature below the melting point thereof in an oxidizing atmosphere to oxidize the surface. Thereafter they are heated to melt at temperature above the melting point of the metals, and the molten metals are separated with the radioactive materials included in the oxides. For instance, radiation-contaminated aluminum pipe placed on the bed of an electrical heating furnace, and heated at 500 0 C which is lower than the melting point 660 0 C of aluminum for 1 - 2 hours while supplying air from an air pipe into the furnace, and an oxide film is formed on the surface of the aluminum pipe. Then, the furnace temperature is increased to 750 0 C wherein molten aluminum is flown down to a container and the oxide film is separated by floating it as the slug on the molten aluminum. (Horiuchi, T.)

    17. Gases and carbon in metals

      International Nuclear Information System (INIS)

      Jehn, H.; Fromm, E.; Hoerz, G.

      1978-01-01

      This issue is part of a series of data on 'gases and carbon in metals'. The present survey includes results from papers dealing with gases and carbon in actinides and recommends critically selected data for each element. Firstly data od binary systems are presented, starting with hydrogen and followed by carbon, nitrogen, oxygen, and rare gases. Within one metal-metalloid system the data are listed under topics such as solubility limit, dissociation pressure of compunds, vapour pressure of volatile oxides, thermodynamic data, diffusion, transport parameters (effective valence, heat of transport), permeation of gases through metals, gas adsorption and gas desorption kinetics, compound formation, precipitation kinetics, and property changes. Following the data on binary systems, the data of ternary systems are presented, beginning with systems which contain one metal and two gases or one gas and carbon and continuing with systems with two metals and one gas or carbon. Within a ternary system the topics are arranged in the same way as in binary systems. (HB) [de

    18. FLIT: Flowing LIquid metal Torus

      Science.gov (United States)

      Kolemen, Egemen; Majeski, Richard; Maingi, Rajesh; Hvasta, Michael

      2017-10-01

      The design and construction of FLIT, Flowing LIquid Torus, at PPPL is presented. FLIT focuses on a liquid metal divertor system suitable for implementation and testing in present-day fusion systems, such as NSTX-U. It is designed as a proof-of-concept fast-flowing liquid metal divertor that can handle heat flux of 10 MW/m2 without an additional cooling system. The 72 cm wide by 107 cm tall torus system consisting of 12 rectangular coils that give 1 Tesla magnetic field in the center and it can operate for greater than 10 seconds at this field. Initially, 30 gallons Galinstan (Ga-In-Sn) will be recirculated using 6 jxB pumps and flow velocities of up to 10 m/s will be achieved on the fully annular divertor plate. FLIT is designed as a flexible machine that will allow experimental testing of various liquid metal injection techniques, study of flow instabilities, and their control in order to prove the feasibility of liquid metal divertor concept for fusion reactors. FLIT: Flowing LIquid metal Torus. This work is supported by the US DOE Contract No. DE-AC02-09CH11466.

    19. Optical characterization of metallic aerosols

      International Nuclear Information System (INIS)

      Sun Wenbo; Lin Bing

      2006-01-01

      Airborne metallic particulates from industry and urban sources are highly conducting aerosols. The characterization of these pollutant particles is important for environment monitoring and protection. Because these metallic particulates are highly reflective, their effect on local weather or regional radiation budget may also need to be studied. In this work, light scattering characteristics of these metallic aerosols are studied using exact solutions on perfectly conducting spherical and cylindrical particles. It is found that for perfectly conducting spheres and cylinders, when scattering angle is larger than ∼90 o the linear polarization degree of the scattered light is very close to zero. This light scattering characteristics of perfectly conducting particles is significantly different from that of other aerosols. When these perfectly conducting particles are immersed in an absorbing medium, this light scattering characteristics does not show significant change. Therefore, measuring the linear polarization of scattered lights at backward scattering angles can detect and distinguish metallic particulates from other aerosols. This result provides a great potential of metallic aerosol detection and monitoring for environmental protection

    20. Estudo comparativo de antieméticos e suas associações, na prevenção de náuseas e vômitos pós-operatórios, em pacientes submetidas a procedimentos cirúrgicos ginecológicos Estudio comparativo de antieméticos y sus asociaciones, en la prevención de náusea y vómito postoperatorios, en pacientes sometidas a procedimientos quirúrgicos ginecológicos Comparative study of anti-emetics and their association, in the prevention of postoperative nausea and vomiting in patients undergoing gynecologic surgeries

      Directory of Open Access Journals (Sweden)

      Taylor Brandão Schnaider

      2008-12-01

      . MÉTODO: Setenta pacientes, ASA I y II, fueron sometidas a procedimientos quirúrgicos ginecológicos, bajo bloqueo epidural asociado a la anestesia general. En el Grupo Metoclopramida (GM, se administró 20 mg; en el Grupo Dexametasona (GDe, se inyectó 8 mg; en el Grupo Droperidol (GDr se administró 1,25 mg; en el Grupo Ondansetron (GO se inyectó 8mg; en el Grupo Dexametasona-Ondansetron (GDeO se administró respectivamente 8 mg y 4mg; en el Grupo Droperidol-Ondansetron (GDrO se inyectó 1,25 mg y 4 mg; en el Grupo Dexametasona-Droperidol-Ondansetron (GDeDrO se administró 8mg, 0,625 mg y 4mg. La presencia de náuseas y vómitos fue observada en los momentos de 6, 12, 24 y 36 horas después del término de la operación. RESULTADOS: La incidencia total de episodios de náuseas fue de 4 en el GDeDrO, 6 en el GO, 6 en el GDrO, 11 en el GDe, 11 en el GDeO, 18 en el GM y 22 en el GDr. Al aplicar el test del Chi-cuadrado o el test de Fisher, se comprobó la diferencia estadística significativa entre el GDr y los grupos GDe, GDO, GDrO, GDeO, GDeDrO; entre el GM y los grupos GO, GDrO y GDeDrO; entre el GDeO y el grupo GDeDrO. La incidencia total de episodios de vómitos fue de 3 en el GO, 3 en el GDeDrO, 6 en el GDrO, 7 en el GDe, 7 en el GDeO, 10 en el GDr y 13 en el G. Se comprobó así mismo, la diferencia estadística significativa entre el GDr y los grupos GO y GDeDrO; entre el GM y los grupos GO y GDeDrO. CONCLUSIONES: La asociación dexametasona-droperidol-ondansetron y el ondansetron fueron más eficaces en la profilaxis de náuseas y vómitos.BACKGROUND AND OBJECTIVES: Prophylaxis of postoperative nausea and vomiting has been the subject of several studies. The objective of the present study was to compare anti-emetics, and their association, in the prevention of postoperative nausea and vomiting. METHODS: Seventy patients, ASA I and II, underwent epidural block associated with general anesthesia for gynecologic surgeries. Patients in the Metochlopramide Group

    1. On mechanism of metals modifying

      International Nuclear Information System (INIS)

      Chernov, V.S.; Busol, F.I.

      1975-01-01

      Data from the literature are cited to show that in several cases, the mechanism of modification of metals and alloys by additives soluble in the melt cannot be explained by the adsorption hypothesis based on the surface activity of these additives. It is suggested that the mechanism of modification by soluble additives can be explained by the presence of a layer of liquid enriched (or depleted) in the additives preceding the crystallization front (densification by concentration), formed under actual conditions of crystallization as a result of the different solubilities of the additive in the solid and liquid phases of the base metal, regardless of its surface activity. This densification by concentration leads to the inhibition of crystal growth in the base metal (barrier action) and to concentration overcooling. On the basis of this theory it is suggested that the modifying action of additives can be predicted from some parameters of the phase diagrams. (author)

    2. Metallic mercury recycling. Final report

      Energy Technology Data Exchange (ETDEWEB)

      Beck, M.A.

      1994-07-01

      Metallic mercury is known to be a hazardous material and is regulated as such. The disposal of mercury, usually by landfill, is expensive and does not remove mercury from the environment. Results from the Metallic Mercury Recycling Project have demonstrated that metallic mercury is a good candidate for reclamation and recycling. Most of the potential contamination of mercury resides in the scum floating on the surface of the mercury. Pinhole filtration was demonstrated to be an inexpensive and easy way of removing residues from mercury. The analysis method is shown to be sufficient for present release practices, and should be sufficient for future release requirements. Data from tests are presented. The consistently higher level of activity of the filter residue versus the bulk mercury is discussed. Recommendations for the recycling procedure are made.

    3. Factors controlling metal fuel lifetime

      International Nuclear Information System (INIS)

      Porter, D.L.; Hofman, G.L.; Seidel, B.R.; Walters, L.C.

      1986-01-01

      The reliability of metal fuel elements is determined by a fuel burnup at which a statistically predicted number of fuel breaches would occur, the number of breaches determined by the amount of free fission gas which a particular reactor design can tolerate. The reliability is therefore measured using experimentally determined breach statistics, or by modelling fuel element behavior and those factors which contribute to cladding breach. The factors are fuel/cladding mechanical and chemical interactions, fission gas pressure, fuel phase transformations involving volume changes, and fission product effects on cladding integrity. Experimental data for EBR-II fuel elements has shown that the primary, and perhaps the only significant factor affecting metal fuel reliability, is the pressure-induced stresses caused by fission gas release. Other metal fuel/cladding systems may perform similarly

    4. Irradiation performance of metallic fuels

      International Nuclear Information System (INIS)

      Pahl, R.G.; Lahm, C.E.; Porter, D.L.; Batte, G.L.; Hofman, G.L.

      1989-01-01

      Argonne National Laboratory has been working for the past five years to develop and demonstrate the Integral Fast Reactor (IFR) concept. The concept involves a closed system for fast-reactor power generation and on-site fuel reprocessing, both designed specifically around the use of metallic fuel. The Experimental Breeder Reactor-II (EBR-II) has used metallic fuel for all of its 25-year life. In 1985, tests were begun to examine the irradiation performance of advanced-design metallic fuel systems based on U-Zr or U-Pu-Zr fuels. These tests have demonstrated the viable performance of these fuel systems to high burnup. The initial testing program will be described in this paper. 2 figs

    5. Thermal Conductivity of Metallic Uranium

      Energy Technology Data Exchange (ETDEWEB)

      Hin, Celine

      2018-03-10

      This project has developed a modeling and simulation approaches to predict the thermal conductivity of metallic fuels and their alloys. We focus on two methods. The first method has been developed by the team at the University of Wisconsin Madison. They developed a practical and general modeling approach for thermal conductivity of metals and metal alloys that integrates ab-initio and semi-empirical physics-based models to maximize the strengths of both techniques. The second method has been developed by the team at Virginia Tech. This approach consists of a determining the thermal conductivity using only ab-initio methods without any fitting parameters. Both methods were complementary. The models incorporated both phonon and electron contributions. Good agreement with experimental data over a wide temperature range were found. The models also provided insight into the different physical factors that govern the thermal conductivity under different temperatures. The models were general enough to incorporate more complex effects like additional alloying species, defects, transmutation products and noble gas bubbles to predict the behavior of complex metallic alloys like U-alloy fuel systems under burnup. 3 Introduction Thermal conductivity is an important thermal physical property affecting the performance and efficiency of metallic fuels [1]. Some experimental measurement of thermal conductivity and its correlation with composition and temperature from empirical fitting are available for U, Zr and their alloys with Pu and other minor actinides. However, as reviewed in by Kim, Cho and Sohn [2], due to the difficulty in doing experiments on actinide materials, thermal conductivities of metallic fuels have only been measured at limited alloy compositions and temperatures, some of them even being negative and unphysical. Furthermore, the correlations developed so far are empirical in nature and may not be accurate when used for prediction at conditions far from those

    6. Hidden scale invariance of metals

      DEFF Research Database (Denmark)

      Hummel, Felix; Kresse, Georg; Dyre, Jeppe C.

      2015-01-01

      Density functional theory (DFT) calculations of 58 liquid elements at their triple point show that most metals exhibit near proportionality between the thermal fluctuations of the virial and the potential energy in the isochoric ensemble. This demonstrates a general “hidden” scale invariance...... of metals making the condensed part of the thermodynamic phase diagram effectively one dimensional with respect to structure and dynamics. DFT computed density scaling exponents, related to the Grüneisen parameter, are in good agreement with experimental values for the 16 elements where reliable data were...... available. Hidden scale invariance is demonstrated in detail for magnesium by showing invariance of structure and dynamics. Computed melting curves of period three metals follow curves with invariance (isomorphs). The experimental structure factor of magnesium is predicted by assuming scale invariant...

    7. Elastic properties of Gum Metal

      International Nuclear Information System (INIS)

      Kuramoto, Shigeru; Furuta, Tadahiko; Hwang, Junghwan; Nishino, Kazuaki; Saito, Takashi

      2006-01-01

      In situ X-ray diffraction measurements under tensile loading and dynamic mechanical analysis were performed to investigate the mechanisms of elastic deformation in Gum Metal. Tensile stress-strain curves for Gum Metal indicate that cold working substantially decreases the elastic modulus while increasing the yield strength, thereby confirming nonlinearity in the elastic range. The gradient of each curve decreased continuously to about one-third its original value near the elastic limit. As a result of this decrease in elastic modulus and nonlinearity, elastic deformability reaches 2.5% after cold working. Superelasticity is attributed to stress-induced martensitic transformations, although the large elastic deformation in Gum Metal is not accompanied by a phase transformation

    8. Metal Fluorides, Metal Chlorides and Halogenated Metal Oxides as Lewis Acidic Heterogeneous Catalysts. Providing Some Context for Nanostructured Metal Fluorides.

      Science.gov (United States)

      Lennon, David; Winfield, John M

      2017-01-28

      Aspects of the chemistry of selected metal fluorides, which are pertinent to their real or potential use as Lewis acidic, heterogeneous catalysts, are reviewed. Particular attention is paid to β-aluminum trifluoride, aluminum chlorofluoride and aluminas γ and η, whose surfaces become partially fluorinated or chlorinated, through pre-treatment with halogenating reagents or during a catalytic reaction. In these cases, direct comparisons with nanostructured metal fluorides are possible. In the second part of the review, attention is directed to iron(III) and copper(II) metal chlorides, whose Lewis acidity and potential redox function have had important catalytic implications in large-scale chlorohydrocarbons chemistry. Recent work, which highlights the complexity of reactions that can occur in the presence of supported copper(II) chloride as an oxychlorination catalyst, is featured. Although direct comparisons with nanostructured fluorides are not currently possible, the work could be relevant to possible future catalytic developments in nanostructured materials.

    9. Forces in Liquid Metal Contacts

      DEFF Research Database (Denmark)

      Duggen, Lars; Mátéfi-Tempfli, Stefan

      2014-01-01

      Using rather well known theory about capillary bridges between two electrodes we calculate the tensile force that can be applied to liquid metal contacts in the micrometer regime. Assuming circular symmetry, full wetting of the electrodes, and neglecting gravity, we present a brief review of the ...... of the necessary theory and find numerically the forces to be in the 100μN range for liquid metals as mercury and liquid Gallium suspended between electrodes of 20μm radius.......Using rather well known theory about capillary bridges between two electrodes we calculate the tensile force that can be applied to liquid metal contacts in the micrometer regime. Assuming circular symmetry, full wetting of the electrodes, and neglecting gravity, we present a brief review...

    10. Simulations of Recrystallization in Metals

      DEFF Research Database (Denmark)

      Godiksen, Rasmus Brauner

      2007-01-01

      structures in the deformed metal due to local effects: Inhomogeneous boundary morphologies and dislocation-structure-dependent migration rates are observed. The effects that the dislocation structures have must be taken into account in order to create realistic recrystallization models, and through......The growth of new near-perfect grains during recrystallization of deformed metals is governed by the migration of the grain boundaries surrounding the new grains. The grain boundaries migrate through the deformed metal driven by the excess energy of the dislocation structures created during...... deformation. Recently, it has been found that recrystallization is far more inhomogeneous than previously thought. The purpose of this PhD-project is to study recrystallization by computer simulations with special focus on inhomogeneous growth. Two types of simulations have been employed: geometric...

    11. Mechanisms of metal dusting corrosion

      DEFF Research Database (Denmark)

      Hummelshøj, Thomas Strabo

      In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... deformed stainless steel flakes is transformed to expanded martensite/austenite during low-temperature carburization. Various experimental procedures to experimentally determine the concentration dependent diffusion coefficient of carbon in expanded austenite are evaluated. The most promising procedure...... powders and flakes. The nature of the decomposition products, carbides of the form M23C6 and M7C3, were evaluated by X-ray diffraction, light optical microscopy, scanning electron microscopy and thermodynamic modelling. The decomposition was found to be dependent on several parameters such as thermal...

    12. Structure and properties of metals

      CERN Document Server

      Kurzydlowski, K J

      1999-01-01

      Metals are one of the most widely used types of engineering materials. Some of their properties, e.g. elastic constants, can be directly related to the nature of the metallic bonds between the atoms. On the other hand, macro- and $9 microstructural features of metals, such as point defects, dislocations, grain boundaries, and second phase particles, control their yield, flow, and fracture stress. Images of microstructural elements can be obtained by modern $9 imaging techniques. Modern computer aided methods can be further used to obtain a quantitative description of these microstructures. These methods take advantage of the progress made in recent years in the field of image processing, $9 mathematical morphology and quantitative stereology. Quantitative description of the microstructures are used for modeling processes taking place under the action of applied load at a given temperature and test (service) environment. $9 These model considerations can be illustrated on the example of an austenitic stainless...

    13. Metallic mercury recycling. Final report

      International Nuclear Information System (INIS)

      Beck, M.A.

      1994-01-01

      Metallic mercury is known to be a hazardous material and is regulated as such. The disposal of mercury, usually by landfill, is expensive and does not remove mercury from the environment. Results from the Metallic Mercury Recycling Project have demonstrated that metallic mercury is a good candidate for reclamation and recycling. Most of the potential contamination of mercury resides in the scum floating on the surface of the mercury. Pinhole filtration was demonstrated to be an inexpensive and easy way of removing residues from mercury. The analysis method is shown to be sufficient for present release practices, and should be sufficient for future release requirements. Data from tests are presented. The consistently higher level of activity of the filter residue versus the bulk mercury is discussed. Recommendations for the recycling procedure are made

    14. Infrared plasmonic nano-lasers based on Metal Insulator Metal waveguides

      NARCIS (Netherlands)

      Hill, M.T.

      2010-01-01

      We will present our latest results on metal-insulator-metal waveguide devices, in particular reducing the dimensions of devices and distributed feedback lasers. Also we will examine potential useful applications for metal nano-lasers.

    15. Process for the disposal of alkali metals

      International Nuclear Information System (INIS)

      Lewis, L.C.

      1979-01-01

      The invention describes a method of disposing of alkali metals by forming a solid waste for storage. The method comprises preparing an aqueous disposal solution of at least 55 weight percent alkali metal hydroxide, heating the alkali metal to melting temperature to form a feed solution, and spraying the molten feed solution into the disposal solution. The alkali metal reacts with the water in the disposal solution in a controlled reaction which produces alkali metal hydroxide, hydrogen and heat and thereby forms a solution of alkali metal hydroxides. Water is added to the solution in amounts sufficient to maintain the concentration of alkali metal hydroxides in the solution at 70 to 90 weight percent, and to maintain the temperature of the solution at about the boiling point. Removing and cooling the alkali metal hydroxide solution thereby forms a solid waste for storage. The method is particularly applicable to radioactive alkali metal reactor coolant. (auth)

    16. Synthesis of vertically aligned metal oxide nanostructures

      KAUST Repository

      Roqan, Iman S.

      2016-03-03

      Metal oxide nanostructure and methods of making metal oxide nanostructures are provided. The metal oxide nanostructures can be 1 -dimensional nanostructures such as nanowires, nanofibers, or nanotubes. The metal oxide nanostructures can be doped or undoped metal oxides. The metal oxide nanostructures can be deposited onto a variety of substrates. The deposition can be performed without high pressures and without the need for seed catalysts on the substrate. The deposition can be performed by laser ablation of a target including a metal oxide and, optionally, a dopant. In some embodiments zinc oxide nanostructures are deposited onto a substrate by pulsed laser deposition of a zinc oxide target using an excimer laser emitting UV radiation. The zinc oxide nanostructure can be doped with a rare earth metal such as gadolinium. The metal oxide nanostructures can be used in many devices including light-emitting diodes and solar cells.

    17. Plastic Deformation of Metal Surfaces

      DEFF Research Database (Denmark)

      Hansen, Niels; Zhang, Xiaodan; Huang, Xiaoxu

      2013-01-01

      of metal components. An optimization of processes and material parameters must be based on a quantification of stress and strain gradients at the surface and in near surface layer where the structural scale can reach few tens of nanometers. For such fine structures it is suggested to quantify structural...... parameters by TEM and EBSD and apply strength-structural relationships established for the bulk metal deformed to high strains. This technique has been applied to steel deformed by high energy shot peening and a calculated stress gradient at or near the surface has been successfully validated by hardness...

    18. Mechanical and metal trades handbook

      CERN Document Server

      2012-01-01

      Englische Ausgabe des vielfach bewährten Tabellenbuchs Metall, 45. Auflage. Translation of the 45th edition of the well-known "Tabellenbuch Metall". It is well suited for shop reference, tooling, machine building, maintenance and as a general book of knowledge. It is also useful for educational purposes, especially in practical work or curricula, continuing education programs. The contents of this book include tables and formulae in eight chapters. The tables contain the most important guidelines, designs, types, dimensions and standard values for their subject areas.

    19. Development of metallic fuel fabrication

      Energy Technology Data Exchange (ETDEWEB)

      Kang, Young Ho; Lee, Chong Yak; Lee, Myung Ho and others

      1999-03-01

      With the vacuum melting and casting of the U-10wt%Zr alloy which is metallic fuel for liquid metal fast breeder reactor, we studied the microstructure of the alloy and the parameters of the melting and casting for the fuel rods. Internal defects of the U-10wt%Zr fuel by gravity casting, were inspected by non-destructive test. U-10wt%Zr alloy has been prepared for the thermal stability test in order to estimate the decomposition of the lamellar structure with relation to swelling under irradiation condition. (author)

    20. Liquid metal cooled nuclear reactor

      International Nuclear Information System (INIS)

      Guidez, Joel; Jarriand, Paul.

      1975-01-01

      The invention concerns a fast neutron nuclear reactor cooled by a liquid metal driven through by a primary pump of the vertical drive shaft type fitted at its lower end with a blade wheel. To each pump is associated an exchanger, annular in shape, fitted with a central bore through which passes the vertical drive shaft of the pump, its wheel being mounted under the exchanger. A collector placed under the wheel comprises an open upward suction bell for the liquid metal. A hydrostatic bearing is located above the wheel to guide the drive shaft and a non detachable diffuser into which at least one delivery pipe gives, envelopes the wheel [fr

    1. Microbial Remediation of Metals in Soils

      Science.gov (United States)

      Hietala, K. A.; Roane, T. M.

      Of metal-contaminated systems, metal-contaminated soils present the greatest challenge to remediation efforts because of the structural, physical, chemical, and biological heterogeneities encountered in soils. One of the confounding issues surrounding metal remediation is that metals can be readily re-mobilized, requiring constant monitoring of metal toxicity in sites where metals are not removed. Excessive metal content in soils can impact air, surface water, and groundwater quality. However, our understanding of how metals affect organisms, from bacteria to plants and animals, and our ability to negate the toxicity of metals are in their infancies. The ubiquity of metal contamination in developing and industrialized areas of the world make remediation of soils via removal, containment, and/or detoxification of metals a primary concern. Recent examples of the health and environmental consequences of metal contamination include arsenic in drinking water (Wang and Wai 2004), mercury levels in fish (Jewett and Duffy 2007), and metal uptake by agricultural crops (Howe et al. 2005). The goal of this chapter is to summarize the traditional approaches and recent developments using microorganisms and microbial products to address metal toxicity and remediation.

    2. Transport properties of metal-metal and metal-insulator heterostructures

      Energy Technology Data Exchange (ETDEWEB)

      Fadlallah Elabd, Mohamed Mostafa

      2010-06-09

      In this study we present results of electronic structure and transport calculations for metallic and metal-insulator interfaces, based on density functional theory and the non-equilibrium Green's function method. Starting from the electronic structure of bulk Al, Cu, Ag, and Au interfaces, we study the effects of different kinds of interface roughness on the transmission coefficient (T(E)) and the I-V characteristic. In particular, we compare prototypical interface distortions, including vacancies, metallic impurities, non-metallic impurities, interlayer, and interface alloy. We find that vacancy sites have a huge effect on transmission coefficient. The transmission coefficient of non-metallic impurity systems has the same behaviour as the transmission coefficient of vacancy system, since these systems do not contribute to the electronic states at the Fermi energy. We have also studied the transport properties of Au-MgO-Au tunnel junctions. In particular, we have investigated the influence of the thickness of the MgO interlayer, the interface termination, the interface spacing, and O vacancies. Additional interface states appear in the O-terminated configuration due to the formation of Au-O bonds. An increasing interface spacing suppresses the Au-O bonding. Enhancement of T(E) depends on the position and density of the vacancies (the number of vacancies per unit cell). (orig.)

    3. Thin films of metal-organic compounds and metal nanoparticle ...

      Indian Academy of Sciences (India)

      Optical limiting capability of the nanoparticle-embedded polymer film is demonstrated. Keywords. Polar crystal; uniaxial orientational order; thin film; second harmonic gen- eration; silver ... able content of metal nanoparticles would be of considerable value from an appli- ... polar chain and perpendicular to it [10].

    4. Spectroscopic monitoring of metallic bonding in laser metal deposition

      NARCIS (Netherlands)

      Ya, Wei; Konuk, A.R.; Aarts, Ronald G.K.M.; Pathiraj, B.; Huis in 't Veld, Bert

      2015-01-01

      A new approach is presented in this paper to link optical emission spectrum analysis to the quality of clad layers produced with laser metal deposition (LMD). A Nd:YAG laser (λ = 1.064 μm) was used to produce clad tracks with Metco 42C powder on AISI 4140 steel substrate. The laser power was ramped

    5. Ferrous and common nonferrous metals industries and associated scrap metals: a review

      International Nuclear Information System (INIS)

      Mautz, E.W.

      1975-11-01

      Literature on the common metals industries, scrap metal relationships, and transportation aspects has been reviewed as background information in a study to determine the feasibility of a portable melting facility for radioactively contaminated metals. This report draws substantially on government-sponsored studies. Aluminum, copper, iron and steel, and nickel metal industries are discussed from the viewpoints of the general industry characteristics, primary metal production processes, and secondary metal processing aspects. 46 references, 10 tables

    6. Recent trends in metals extraction

      Directory of Open Access Journals (Sweden)

      Regel-Rosocka, M.

      2013-08-01

      Full Text Available After near 70 years of practical usage, solvent extraction is a perfectly mastered technique of separation, widely used on an industrial scale for the separation of metals mainly from raw materials. However, currently, in the era of depleting natural resources and increasingly less accessible deposits, environmental restrictions, etc., an increasing interest, both from social and economical constrains, is being directed at the extraction of metals from the secondary sources (such as batteries, electronic scrap. In many cases, solvent extraction, due to its operational characteristics, can be considered as the Best Available Technology for the purpose of separating multielemental metal solutions. This paper provides a brief overview of past achievements and present scenario of solvent extraction investigations and developments, describing some recently commissioned solvent extraction plants, whereas the Skorpion Zinc plant (Namibia for zinc extraction from raw materials and caesium removal from radioactive High Level Wastes (HLWs are told over in detail as case studies. The paper also presents some proposals for the use of liquid-liquid extraction to separate metal ions from secondary sources (e.g. cobalt from industrial waste streams. The review highlights the emerging use of ionic liquids as new extractants for metals, providing an insight into this exciting research field. Despite its detractors, solvent extraction has entered in force into XXI century as a leading separation technology for metals.Después de casi 70 años de uso práctico, la extracción líquido-líquido o extracción con disolventes es una técnica de separación muy evolucionada, utilizándose a escala industrial en el beneficio de metales obtenidos de diversas materias primas. Sin embargo, con el agotamiento de los recursos naturales y el aumento de depósitos minerales de más difícil acceso, restricciones medio ambientales, etc., ha aumentado el interés, tanto desde

    7. Stiffness management of sheet metal parts using laser metal deposition

      Science.gov (United States)

      Bambach, Markus; Sviridov, Alexander; Weisheit, Andreas

      2017-10-01

      Tailored blanks are established solutions for the production of load-adapted sheet metal components. In the course of the individualization of production, such semi-finished products are gaining importance. In addition to tailored welded blanks and tailored rolled blanks, patchwork blanks have been developed which allow a local increase in sheet thickness by welding, gluing or soldering patches onto sheet metal blanks. Patchwork blanks, however, have several limitations, on the one hand, the limited freedom of design in the production of patchwork blanks and, on the other hand, the fact that there is no optimum material bonding with the substrate. The increasing production of derivative and special vehicles on the basis of standard vehicles, prototype production and the functionalization of components require solutions with which semi-finished products and sheet metal components can be provided flexibly with local thickenings or functional elements with a firm metallurgical bond to the substrate. An alternative to tailored and patchwork blanks is, therefore, a free-form reinforcement applied by additive manufacturing via laser metal deposition (LMD). By combining metal forming and additive manufacturing, stiffness can be adapted to the loads based on standard components in a material-efficient manner and without the need to redesign the forming tools. This paper details a study of the potential of stiffness management by LMD using a demonstrator part. Sizing optimization is performed and part distortion is taken into account to find an optimal design for the cladding. A maximum stiffness increase of 167% is feasible with only 4.7% additional mass. Avoiding part distortion leads to a pareto-optimal design which achieves 95% more stiffness with 6% added mass.

    8. On the determination of various metallic and nonmetallic impurities in sodium metal

      International Nuclear Information System (INIS)

      Schneider, H.; Gruenhaeuser, M.; Nagel, G.; Nold, E.; Schaefer, A.; Schumann, H.

      1976-04-01

      Methods for the determination of various metallic and nonmetallic impurities in sodium metal were developed or tested. Detection limits, reproducibilities and results of analyses are reported. (orig.) [de

    9. High Re-Operation Rates Using Conserve Metal-On-Metal Total Hip Articulations

      DEFF Research Database (Denmark)

      Mogensen, S L; Jakobsen, Thomas; Christoffersen, Hardy

      2016-01-01

      INTRODUCTION: Metal-on-metal hip articulations have been intensely debated after reports of adverse reactions and high failure rates. The aim of this study was to retrospectively evaluate the implant of a metal-on.metal total hip articulation (MOM THA) from a single manufacture in a two-center st......INTRODUCTION: Metal-on-metal hip articulations have been intensely debated after reports of adverse reactions and high failure rates. The aim of this study was to retrospectively evaluate the implant of a metal-on.metal total hip articulation (MOM THA) from a single manufacture in a two...

    10. Phytoremediation of heavy metal polluted sites

      International Nuclear Information System (INIS)

      Aery, N.C.; Panchal, Jayesh

      2007-01-01

      The nature of soil, the contaminant's chemical and physical characteristics and environmental factors such as climate and hydrology interact to determine the accumulation, mobility, toxicity, and overall significance of the contaminant in any specific instance. Although many metals are essential, all metals are toxic at higher concentrations, because they cause oxidative stress by formation of free radicals. Another reason why metals may be toxic is that they can replace essential metals in enzymes disrupting their function. Thus, metals render the land unsuitable for plant growth and destroy the biodiversity. Metal contaminated soil can be remediated by chemical, physical and biological techniques

    11. Propagation Characteristics of Multilayer Hybrid Insulator-Metal-Insulator and Metal-Insulator-Metal Plasmonic Waveguides

      Directory of Open Access Journals (Sweden)

      M. Talafi Noghani

      2014-02-01

      Full Text Available Propagation characteristics of symmetrical and asymmetrical multilayer hybrid insulator-metal-insulator (HIMI and metal-insulator-metal (HMIM plasmonic slab waveguides are investigated using the transfer matrix method. Propagation length (Lp and spatial length (Ls are used as two figures of merit to qualitate the plasmonic waveguides. Symmetrical structures are shown to be more performant (having higher Lp and lower Ls, nevertheless it is shown that usage of asymmetrical geometry could compensate for the performance degradation in practically realized HIMI waveguides with different substrate materials. It is found that HMIM slab waveguide could support almost long-range subdiffraction plasmonic modes at dimensions lower than the spatial length of the HIMI slab waveguide.

    12. Analysis of autofrettaged metal tubes

      International Nuclear Information System (INIS)

      Malik, M. Afzaal; Khan, Muddasar; Rashid, Badar; Khushnood, Shahab

      2007-01-01

      Thick-walled cylinders are widely used as compressor cylinders, pump cylinders, high pressure tubing, process reactors and vessels, nuclear reactors, isostatic vessels and gun barrels. In practice, cylinders are generally subjected to sudden and frequently drastic pressure fluctuations, such as the pressure generated in a gun barrel upon the firing of the weapon, pressure reversals in pump cylinders or in process reactors employing high-pressure piping, necessitating enhanced strength of such cylinders. A process for enhancing the strength of thick-walled cylinders has been in service, and is referred to as 'autofrettage'. It extends the service life of the cylinder. The autofrettage is achieved by increasing elastic strength of a cylinder with various methods such as hydraulic pressurization, mechanical swaging, or by utilizing the pressure of a powder gas. This research work deals with the hydraulic and mechanical autofrettage of metal tubes with the objective to attain enhanced strength. Five metal tubes are taken randomly for analysis purpose. The experimental data for five metal tubes is obtained to analyze the behavior of different parameters used during, before, and after autofrettage process. For this research, two-stage autofrettage is taken into consideration. The modeling of the metal tube is carried out in WildFire-ProEngineering, and for analysis purpose, finite element software ANSYS7 and COSMOS are used. The graphical analysis of swage autofrettage is carried out using MATLAB7. The results are validated using available experimental and numerical data. (author)

    13. Kolm maailma metallis / Tanel Veenre

      Index Scriptorium Estoniae

      Veenre, Tanel, 1977-

      2011-01-01

      Näitused Tallinnas: Maria Valdma "Võõrastemaja" Iida galeriis 31. jaan.-ni 2012, Kaie Partsi retrospektiivnäitus "Metall ja kivi" Vabaduse galeriis 6. dets.-ni 2011, Ülle Kõutsi "Vesi" A-Galeriis 5. dets.-ni 2011

    14. Plasmon tsunamis on metallic nanoclusters.

      Science.gov (United States)

      Lucas, A A; Sunjic, M

      2012-03-14

      A model is constructed to describe inelastic scattering events accompanying electron capture by a highly charged ion flying by a metallic nanosphere. The electronic energy liberated by an electron leaving the Fermi level of the metal and dropping into a deep Rydberg state of the ion is used to increase the ion kinetic energy and, simultaneously, to excite multiple surface plasmons around the positively charged hole left behind on the metal sphere. This tsunami-like phenomenon manifests itself as periodic oscillations in the kinetic energy gain spectrum of the ion. The theory developed here extends our previous treatment (Lucas et al 2011 New J. Phys. 13 013034) of the Ar(q+)/C(60) charge exchange system. We provide an analysis of how the individual multipolar surface plasmons of the metallic sphere contribute to the formation of the oscillatory gain spectrum. Gain spectra showing characteristic, tsunami-like oscillations are simulated for Ar(15+) ions capturing one electron in distant collisions with Al and Na nanoclusters.

    15. Supersonic bare metal cluster beams

      International Nuclear Information System (INIS)

      Smalley, R.E.

      1991-01-01

      Progress continued this past year on two principal fronts in the study of bare metal clusters: photoelectron spectroscopy of mass selected negative ions, and surface chemisorption of cluster ions levitated in a superconducting magnet as monitored by fourier transform ion cyclotron resonance

    16. Reynolds Metals Company, Massena, NY

      Science.gov (United States)

      The 1,600-acre former Reynolds Metals Facility is located on the St. Lawrence River, approximately eight miles east of the Village of Massena, New York. The facility, which was constructed in 1958 for the production of aluminum, closed in 2014. It is owned

    17. Nanostructured metals. Fundamentals to applications

      International Nuclear Information System (INIS)

      Grivel, J.-C.; Hansen, N.; Huang, X.; Juul Jensen, D.; Mishin, O.V.; Nielsen, S.F.; Pantleon, W.; Toftegaard, H.; Winther, G.; Yu, T.

      2009-01-01

      In the today's world, materials science and engineering must as other technical fields focus on sustainability. Raw materials and energy have to be conserved and metals with improved or new structural and functional properties must be invented, developed and brought to application. In this endeavour a very promising route is to reduce the structural scale of metallic materials, thereby bridging industrial metals of today with emerging nanometals of tomorrow, i.e. structural scales ranging from a few micrometres to the nanometre regime. While taking a focus on metals with structures in this scale regime the symposium spans from fundamental aspects towards applications, uniting materials scientists and technologists. A holistic approach characterizes the themes of the symposium encompassing synthesis, characterization, modelling and performance where in each area significant progress has been made in recent years. Synthesis now covers top-down processes, e.g. plastic deformation, and bottom-up processes, e.g. chemical and physical synthesis. In the area of structural and mechanical characterization advanced techniques are now widely applied and in-situ techniques for structural characterization under mechanical or thermal loading are under rapid development in both 2D and 3D. Progress in characterization techniques has led to a precise description of different boundaries (grain, dislocation, twin, phase), and of how they form and evolve, also including theoretical modelling and simulations of structures, properties and performance. (au)

    18. Green Lubricants for Metal Forming

      DEFF Research Database (Denmark)

      Bay, Niels

      2010-01-01

      The increasing focus on legislation towards diminishing the impact on working environment as well as external environment has driven efforts to develop new, environmentally benign lubricants for metal forming. The present paper gives an overview of these efforts to substitute environmentally...

    19. Model Based Metal Transfer Control

      DEFF Research Database (Denmark)

      Thomsen, Jesper Sandberg

      2006-01-01

      In pulsed gas metal arc welding (pulsed GMAW) current pulses are used for detaching drops at the tip of the electrode. To obtain a high weld quality one drop should be detached for every pulse, and moreover, the amount of energy used for detachment should be kept at a minimum. Thus, each pulse must...

    20. Cellular uptake of metallated cobalamins

      DEFF Research Database (Denmark)

      Tran, Mai Thanh Quynh; Stürup, Stefan; Lambert, Ian Henry

      2016-01-01

      Cellular uptake of vitamin B12-cisplatin conjugates was estimated via detection of their metal constituents (Co, Pt, and Re) by inductively coupled plasma mass spectrometry (ICP-MS). Vitamin B12 (cyano-cob(iii)alamin) and aquo-cob(iii)alamin [Cbl-OH2](+), which differ in the β-axial ligands (CN...

    1. Optical conductivity of metal nanoshells

      International Nuclear Information System (INIS)

      Tomchuk, P.M.; Kulish, V.V.

      2004-01-01

      The expression for optical conductivity of spherical metal nanoshell as a function of internal and external radii of nanoshell and photon energy - Fermi energy ratio is obtained. Quantization of electron energy in nanoshells is shown to lead to the appearance of an oscillating dependence of optical conductivity on the light frequency. An explicit expression of oscillating addends for optical conductivity is obtained

    2. Stress in hard metal films

      NARCIS (Netherlands)

      Janssen, G.C.A.M.; Kamminga, J.D.

      2004-01-01

      In the absence of thermal stress, tensile stress in hard metal films is caused by grain boundary shrinkage and compressive stress is caused by ion peening. It is shown that the two contributions are additive. Moreover tensile stress generated at the grain boundaries does not relax by ion

    3. Metals industry seeks economic comeback

      International Nuclear Information System (INIS)

      Nappi, C.

      1993-01-01

      The North American minerals and metals industry has experienced a shockwave of change during the past two decades but is making a gallant comeback attempt, says Carmine Nappi, a mineral economist at the University of Montreal in Canada. Beginning in the mid-1970s, demand for major metals-aluminum, copper, lead, nickel, and zinc-dropped precipitately as the industrialized world shifted from a products to a services economy and as manufacturers discovered ways to make their products lighter, smaller, and more efficient. At the same time, Nappi says, rising energy and environmental costs pushed mining costs upward and squeezed profit margins, while foreign competitors stepped up their pressure. As a result, more than 7,000 US jobs in the minerals and metals industry were lost between 1980 and 1985. The value of mining production dropped $3.3 billion, and the industry went from $1.9 billion in profits to $900 million in losses. The industry responded to the crisis in different ways, Nappi says. Most zinc producers simply shut down, and many aluminum smelters, especially in the Southeast, also became resigned to their fate. Copper producers, however, fought back, changed the ways they did business, and survived. While conceding that the North American minerals and metals industry may never be as robust again as it was two decades ago, Nappi says the recent changes have slowed, and in some cases reversed, the hemorrhaging

    4. The surface energy of metals

      DEFF Research Database (Denmark)

      Vitos, Levente; Ruban, Andrei; Skriver, Hans Lomholt

      1998-01-01

      We have used density functional theory to establish a database of surface energies for low index surfaces of 60 metals in the periodic table. The data may be used as a consistent starting point for models of surface science phenomena. The accuracy of the database is established in a comparison...

    5. REVIEW ABOUT METAL PARTS RECONDITIONING

      Directory of Open Access Journals (Sweden)

      DAN FLORIN NITOI

      2015-05-01

      Full Text Available Paper realize a presentation of different deposition methods starting with the definition of this procedure including all the advantages and disadvantages. It is presented the welding technology with its different methods, the metalization method, all in order to choose the proper technology for different reconditioning situations in industry.

    6. Metal corrosion inhibitors and ecology

      International Nuclear Information System (INIS)

      Krasts, H.; Svarce, J.; Berge, B.

      1999-01-01

      The use of metal corrosion inhibitors in water is one of the cheapest method to protect metals against corrosion. However, the used inhibitors can come to surface water in the course of time and can become as source of environmental pollution. It is important to co-ordinate amount of substances in the elaborated inhibitors not only with demands for metal protection, but also with demands for quality of surface water and drinking water according to normative statements: 3.5 mg/l (as PO 4 ) for hexametaphosphate, tripolyphosphate and phosphonate; 40 mg/l (as SiO 2 for silicate, up to 1 mg/l for CU 2+ ; up to 5 mg/l for Zn 2+ ; up to 1 mg/l for B; up to 0.5 mg/l for Mo 2+ . The examples of the elaborated inhibitors are given. Many organic substances can be used as corrosion inhibitors, but there is shortage of standard methods for their analysis in water in Latvia. Removing of salt's deposits from boilers needs elaboration of a separate normative statement for dispersing waste water which content chloride at high concentration and heavy metals. (authors)

    7. Melting of contaminated metallic waste

      International Nuclear Information System (INIS)

      Lee, Y.-S.; Cheng, S.-Y.; Kung, H.-T.; Lin, L.-F.

      2004-01-01

      Approximately 100 tons of contaminated metallic wastes were produced each year due to maintenance for each TPC's nuclear power reactor and it was roughly estimated that there will be 10,000 tons of metallic scraps resulted from decommissioning of each reactor in the future. One means of handling the contaminated metal is to melt it. Melting process owns not only volume reduction which saves the high cost of final disposal but also resource conservation and recycling benefits. Melting contaminated copper and aluminum scraps in the laboratory scale have been conducted at INER. A total of 546 kg copper condenser tubes with a specific activity of about 2.7 Bq/g was melted in a vacuum induction melting facility. Three types of products, ingot, slag and dust were derived from the melting process, with average activities of 0.10 Bq/g, 2.33 Bq/g and 84.3 Bq/g respectively. After the laboratory melting stage, a pilot plant with a 500 kg induction furnace is being designed to melt the increasingly produced contaminated metallic scraps from nuclear facilities and to investigate the behavior of different radionuclides during melting. (author)

    8. Transition Metal Complexes and Catalysis

      Indian Academy of Sciences (India)

      approaches towards the study of bonding in transition metal complexes. Despite .... industrial scale reactions for the production of organic compounds using transition ..... It has found several applications as an engineering thermoplastic. .... and processes of interest to the company, that is, applied research. It is this very ...

    9. Liquid metal cooled nuclear reactors

      International Nuclear Information System (INIS)

      Scott, D.

      1981-01-01

      An improved method of constructing the diagrid used to support fuel assemblies of liquid metal fast breeder reactors, is described. The functions of fuel assembly support and coolant plenum are performed by discrete components of the diagrid each of which can serve the function of the other in the event of failure of one of the components. (U.K.)

    10. Formation mechanisms of metal colloids

      Science.gov (United States)

      Halaciuga, Ionel

      Highly dispersed uniform metallic particles are widely used in various areas of technology and medicine and are likely to be incorporated into many other applications in the future. It is commonly accepted that size, shape and composition of the particles represent critical factors in most applications. Thus, understanding the mechanisms of formation of metal particles and the ways to control the physical (e.g. shape, size) and chemical (e.g. composition) properties is of great importance. In the current research, the formation of uniform silver spheres is investigated experimentally. The parameters that influence the formation of silver particles when concentrated iso-ascorbic acid and silver-polyamine complex solutions are rapidly mixed were studied in the absence of dispersants. We found that by varying the nature of the amine, temperature, concentration of reactants, silver/amine molar ratio, and the nature of the silver salt, the size of the resulting silver particles can be varied in a wide range (0.08--1.5 microm). The silver particles were formed by aggregation of nanosize subunits as substantiated by both electron microscopy and X-ray diffraction techniques and by the vivid rapid color changes during the chemical precipitation process. From the practical standpoint, the goal of this research was to prepare well dispersed spherical silver particles having a relatively smooth surface and a diameter of about 1 microm to satisfy the demands of the current electronic materials market. A two stage particle growth model previously developed to explain the narrow size distribution occurring in synthesis of gold spheres was applied to the present experimental system, and the parameters that control the size distribution characteristics were identified. The kinetic parameter required to match the final particle size was found to be in agreement with the one used previously in modeling formation of gold spheres, suggesting that similar kinetics governs the

    11. Liquid metal thermal-hydraulics

      International Nuclear Information System (INIS)

      Kottowski-Duemenil, H.M.

      1994-01-01

      This textbook is a report of the 26 years activity of the Liquid Metal Boiling Working Group (LMBWG). It summarizes the state of the art of liquid metal thermo-hydraulics achieved through the collaboration of scientists concerned with the development of the Fast Breeder Reactor. The first chapter entitled ''Liquid Metal Boiling Behaviour'', presents the background and boiling mechanisms. This section gives the reader a brief but thorough survey on the superheat phenomena in liquid metals. The second chapter of the text, ''A Review of Single and Two-Phase Flow Pressure Drop Studies and Application to Flow Stability Analysis of Boiling Liquid Metal Systems'' summarizes the difficulty of pressure drop simulation of boiling sodium in core bundles. The third chapter ''Liquid Metal Dry-Out Data for Flow in Tubes and Bundles'' describes the conditions of critical heat flux which limits the coolability of the reactor core. The fourth chapter dealing with the LMFBR specific topic of ''Natural Convection Cooling of Liquid Metal Systems''. This chapter gives a review of both plant experiments and out-of-pile experiments and shows the advances in the development of computing power over the past decade of mathematical modelling ''Subassembly Blockages Suties'' are discussed in chapter five. Chapter six is entitled ''A Review of the Methods and Codes Available for the Calculation on Thermal-Hydraulics in Rod-Cluster and other Geometries, Steady state and Transient Boiling Flow Regimes, and the Validation achieves''. Codes available for the calculation of thermal-hydraulics in rod-clusters and other geometries are reviewed. Chapter seven, ''Comparative Studies of Thermohydraulic Computer Code Simulations of Sodium Boiling under Loss of Flow Conditions'', represents one of the key activities of the LMBWG. Several benchmark exercises were performed with the aim of transient sodium boiling simulation in single channels and bundle blockages under steady state conditions and loss of

    12. Electrochemical Applications in Metal Bioleaching.

      Science.gov (United States)

      Tanne, Christoph Kurt; Schippers, Axel

      2017-12-10

      Biohydrometallurgy comprises the recovery of metals by biologically catalyzed metal dissolution from solids in an aqueous solution. The application of this kind of bioprocessing is described as "biomining," referring to either bioleaching or biooxidation of sulfide metal ores. Acidophilic iron- and sulfur-oxidizing microorganisms are the key to successful biomining. However, minerals such as primary copper sulfides are recalcitrant to dissolution, which is probably due to their semiconductivity or passivation effects, resulting in low reaction rates. Thus, further improvements of the bioleaching process are recommendable. Mineral sulfide dissolution is based on redox reactions and can be accomplished by electrochemical technologies. The impact of electrochemistry on biohydrometallurgy affects processing as well as analytics. Electroanalysis is still the most widely used electrochemical application in mineralogical research. Electrochemical processing can contribute to bioleaching in two ways. The first approach is the coupling of a mineral sulfide to a galvanic partner or electrocatalyst (spontaneous electron transfer). This approach requires only low energy consumption and takes place without technical installations by the addition of higher redox potential minerals (mostly pyrite), carbonic material, or electrocatalytic ions (mostly silver ions). Consequently, the processed mineral (often chalcopyrite) is preferentially dissolved. The second approach is the application of electrolytic bioreactors (controlled electron transfer). The electrochemical regulation of electrolyte properties by such reactors has found most consideration. It implies the regulation of ferrous and ferric ion ratios, which further results in optimized solution redox potential, less passivation effects, and promotion of microbial activity. However, many questions remain open and it is recommended that reactor and electrode designs are improved, with the aim of finding options for simplified

    13. Electrical transport through a metal-molecule-metal junction; Transport electrique a travers une jonction metal-molecule-metal

      Energy Technology Data Exchange (ETDEWEB)

      Kergueris, Ch

      1998-12-17

      We investigate the electrical transport through a very few molecules connected to metallic electrodes at room temperature. First, the state of the art in molecular electronics is outlined. We present the most convincing molecular devices reported so far in the literature and the theoretical tools available to analyze the electron transport mechanism through a molecular junction. Second, we describe the use of mechanically controllable break junctions to investigate the electron transport properties through a metal-molecule-metal junction. Two kindsof molecules were adsorbed on the two facing gold electrodes, dodecane-thiol (DT) and bis-thiol-ter-thiophene ({alpha},{omega} T3), that are basically expected to behave as an insulator and as a molecular wire, respectively. In the latter case, we study the chemical reactivity of the molecule and show that {alpha},{omega} T3 is chemically adsorbed on gold electrodes. Current-voltage characteristics of the junction were observed at room temperature. The Gold-DT-Gold junction behaves as a simple metal-insulator-metal junction. On the other hand, the electron transport through a Gold-{alpha},{omega} T3-Gold junction explicitly involves the electronic structure of the molecule which gives rise to step-like features in the current-voltage characteristics. The measured zero bias conductance is interpreted using the scattering theory. At high bias, we discuss two different models: a coherent model where the electron has no time to be completely re-localized in the molecule and a sequential model where the electron is localized in the molecule during the transfer. Finally, we show that the mechanical action of decreasing the inter-electrodes spacing can be used to induce a strong modification of the current-voltage characteristics. (author)

    14. Emerging Science and Research Opportunities for Metals and Metallic Nanostructures

      Science.gov (United States)

      Handwerker, Carol A.; Pollock, Tresa M.

      2014-07-01

      During the next decade, fundamental research on metals and metallic nanostructures (MMNs) has the potential to continue transforming metals science into innovative materials, devices, and systems. A workshop to identify emerging and potentially transformative research areas in MMNs was held June 13 and 14, 2012, at the University of California Santa Barbara. There were 47 attendees at the workshop (listed in the Acknowledgements section), representing a broad range of academic institutions, industry, and government laboratories. The metals and metallic nanostructures (MMNs) workshop aimed to identify significant research trends, scientific fundamentals, and recent breakthroughs that can enable new or enhanced MMN performance, either alone or in a more complex materials system, for a wide range of applications. Additionally, the role that MMN research can play in high-priority research and development (R&D) areas such as the U.S. Materials Genome Initiative, the National Nanotechnology Initiative, the Advanced Manufacturing Initiative, and other similar initiatives that exist internationally was assessed. The workshop also addressed critical issues related to materials research instrumentation and the cyberinfrastructure for materials science research and education, as well as science, technology, engineering, and mathematics (STEM) workforce development, with emphasis on the United States but with an appreciation that similar challenges and opportunities for the materials community exist internationally. A central theme of the workshop was that research in MMNs has provided and will continue to provide societal benefits through the integration of experiment, theory, and simulation to link atomistic, nanoscale, microscale, and mesoscale phenomena across time scales for an ever-widening range of applications. Within this overarching theme, the workshop participants identified emerging research opportunities that are categorized and described in more detail in the

    15. Relationship between metal speciation in soil solution and metal adsorption at the root surface of ryegrass.

      Science.gov (United States)

      Kalis, Erwin J J; Temminghoff, Erwin J M; Town, Raewyn M; Unsworth, Emily R; van Riemsdijk, Willem H

      2008-01-01

      The total metal content of the soil or total metal concentration in the soil solution is not always a good indicator for metal availability to plants. Therefore, several speciation techniques have been developed that measure a defined fraction of the total metal concentration in the soil solution. In this study the Donnan Membrane Technique (DMT) was used to measure free metal ion concentrations in CaCl(2) extractions (to mimic the soil solution, and to work under standardized conditions) of 10 different soils, whereas diffusive gradients in thin-films (DGT) and scanning chronopotentiometry (SCP) were used to measure the sum of free and labile metal concentrations in the CaCl(2) extracts. The DGT device was also exposed directly to the (wetted) soil (soil-DGT). The metal concentrations measured with the speciation techniques are related to the metal adsorption at the root surface of ryegrass (Lolium perenne L.), to be able to subsequently predict metal uptake. In most cases the metal adsorption related pH-dependently to the metal concentrations measured by DMT, SCP, and DGT in the CaCl(2) extract. However, the relationship between metal adsorption at the root surface and the metal concentrations measured by the soil-DGT was not-or only slightly-pH dependent. The correlations between metal adsorption at the root surface and metal speciation detected by different speciation techniques allow discussion about rate limiting steps in biouptake and the contribution of metal complexes to metal bioavailability.

    16. Estudio macroscópico y genético de piezas dentarias sometidas a calor con fines forenses

      OpenAIRE

      Sioli Durán, José Manuel

      2015-01-01

      Introducción: muchos casos forenses precisan la interpretación de cadáveres humanos quemados, carbonizados y/o incinerados, como es el caso de accidentes aéreos, automovilísticos, atentados con bombas, cremaciones ilícitas, y en menor medida, en homicidios, suicidios, e incluso muertes accidentales. En situaciones extremas, donde la acción del fuego daña o degrada excesivamente la totalidad de los tejidos, suelen ser los huesos y más aún los dientes, la única evidencia disponible en los proce...

    17. Comportamiento de tejas de cubierta tipo multicapa fabricadas con asfalto crudo y modificado cuando son sometidas a cargas constantes

      OpenAIRE

      López Bula, Pedro Javier

      2011-01-01

      El presente trabajo, analiza las propiedades viscoelasticas de diferentes materiales asfalticos después de ser sometidos a cargas permanentes y a diferente temperatura -- Estas cargas simulan las que eventualmente se pueden presentar en la aplicacion y fabricación de productos asfalticos ampliamente utilizados en el sector de la construcción -- Para este estudio se utilizó asfalto crudo y modificado con diferentes polímeros: Cera de polietileno (CERA), caucho molido de llanta (CR), copolimero...

    18. Estudio electroencefalográfico de las alteraciones de vigilia y sueño en ratas sometidas a pesticidas.

      OpenAIRE

      Victorio Muñoz, Rut

      2017-01-01

      Resumen: Introducción: En los últimos años existe una gran preocupación por el aumento de la incidencia de los trastornos del aprendizaje y del desarrollo en niños. Por ejemplo, las tasas de prevalencia del trastorno del espectro autista (TEA) y del trastorno por déficit de atención e hiperactividad (TDAH) parecen ir en aumento en todo el mundo. El uso de sustancias químicas (pesticidas) en agricultura y en el hogar para combatir diferentes plagas no sólo tiene beneficios asociados, si...

    19. PLASTICIDAD FENOTÍPICA EN PLANTAS DE LIPPIA DULCIS (VERBENACEAE) SOMETIDAS A DÉFICIT HÍDRICO

      OpenAIRE

      JAVIER MAURICIO VILLAMIZAR CÚJAR; NELSON FACUNDO RODRÍGUEZ LÓPEZ; WILMER TEZARA FERNÁNDEZ

      2012-01-01

      La plasticidad fenotípica (PF) es un mecanismo mediante el cual las plantas pueden responder a la heterogeneidad ambiental con ajustes morfológicos y fisiológicos. En este estudio se cuantificó la PF de plantas de Lippia dulcis en respuesta a la disponibilidad hídrica en el suelo (baja, moderada y alta), en caracteres morfológicos y de asignación de biomasa, durante la ontogenia vegetativa (días 39, 45, 59 y 66). Nuestra hipótesis planteó que como respuesta a la disponibilidad hídrica, deberí...

    20. PLASTICIDAD FENOTÍPICA EN PLANTAS DE Lippia dulcis (VERBENACEAE SOMETIDAS A DÉFICIT HÍDRICO

      Directory of Open Access Journals (Sweden)

      Javier Mauricio Villamizar Cújar

      2012-05-01

      Full Text Available La plasticidad fenotípica (PF es un mecanismo mediante el cual las plantas pueden responder a la heterogeneidad ambiental con ajustes morfológicos y fisiológicos. En este estudio se cuantificó la PF de plantas de Lippia dulcis en respuesta a la disponibilidad hídrica en el suelo (baja, moderada y alta. Se evaluó la PF en caracteres morfológicos y de asignación de biomasa, durante la ontogenia vegetativa de L. dulcis (días 39, 45, 59 y 66. Nuestra hipótesis planteó que como respuesta a la disponibilidad hídrica, debería esperarse una mayor PF en caracteres morfológicos en comparación con caracteres de asignación de biomasa. La fracción de masa foliar, razón del área foliar, longitud de las ramas, número de hojas, así como la razón biomasa de la raíz/biomasa foliar,  presentaron la mayor capacidad de ajuste plástico en las plantas de L dulcis al déficit hídrico, mientras que el área foliar especifica representó el carácter con menor PF a lo largo de la ontogenia vegetativa. La magnitud y patrón de la PF variaron dependiendo del carácter, tratamiento y con el desarrollo ontogénico. Contrario a nuestra hipótesis, el grupo de caracteres morfológicos y de asignación de biomasa, exhibieron una PF equivalentes. Los modelos de asignación y forrajeo óptimo bajo condiciones de déficit hídrico no son mutuamente excluyentes. L.dulcis alteró sus patrones de asignación de biomasa, la morfología foliar y radicular, y como beneficio adaptativo optimizó la asimilación de agua y la eficiencia en el uso del agua. L. dulcis exhibió una notable tolerancia al déficit hídrico.

    1. Macroinfauna en playas arenosas de la costa del Norte Grande de Chile sometidas a diferentes presiones antrópicas

      OpenAIRE

      Acuña, Emilio O; Jaramillo, Eduardo

      2015-01-01

      Las playas arenosas urbanas son afectadas por limpieza artificial y recreación, lo que resulta en perturbación de los sedimentos y la macroinfauna. Durante octubre 2012, se muestrearon 3 playas urbanas y 4 no urbanas a lo largo de la costa del norte de Chile (ca., 20-21°S), para evaluar la estructura comunitaria de la macroinfauna intermareal. Se replicaron 4 transectos perpendiculares a la línea de costa extendidos entre el intermareal superior y el nivel de la marea baja, para recolectar mu...

    2. Implicaciones anestésicas de la obesidad en pacientes sometidas a una cesárea

      OpenAIRE

      Serrano, Mari Luz

      2009-01-01

      La obesidad en la embarazada debe ser considerada una situación de alto riesgo porque se asocia a complicaciones a corto y largo plazo. La obesidad supone un factor de riesgo anestésico. En el informe presentado en 2007 por "The Confidential Enquiry into Maternal and Child Health" (CEMACH) había seis muertes que estaban directamente relacionadas con la anestesia de las que cuatro eran pacientes obesas y dos obesas mórbidas. Además de la patología previa coexistente con la obesidad como ...

    3. Material efficiency: rare and critical metals.

      Science.gov (United States)

      Ayres, Robert U; Peiró, Laura Talens

      2013-03-13

      In the last few decades, progress in electronics, especially, has resulted in important new uses for a number of geologically rare metals, some of which were mere curiosities in the past. Most of them are not mined for their own sake (gold, the platinum group metals and the rare Earth elements are exceptions) but are found mainly in the ores of the major industrial metals, such as aluminium, copper, zinc and nickel. We call these major metals 'attractors' and the rare accompanying metals 'hitch-hikers'. The key implication is that rising prices do not necessarily call forth greater output because that would normally require greater output of the attractor metal. We trace the geological relationships and the functional uses of these metals. Some of these metals appear to be irreplaceable in the sense that there are no known substitutes for them in their current functional uses. Recycling is going to be increasingly important, notwithstanding a number of barriers.

    4. Environmentally friendly preparation of metal nanoparticles

      Science.gov (United States)

      The book chapter summarizes the “state of the art” in the exploitation of various environmentally-friendly synthesis approaches, reaction precursors and conditions to manufacture metal and metal oxide nanoparticles for a vast variety of purposes.

    5. Heavy metals in Mindhola river estuary, India

      Digital Repository Service at National Institute of Oceanography (India)

      Zingde, M.D.; Rokade, M.A; Mandalia, A

      The heavy metal concentrations are studied along the Mindhola river estuary. Surface and bottom water samples were collected using Niskin Sampler. The sediment samples were collected using a Van Veen grab. The heavy metal concentration is estimated...

    6. THE IMPACT OF HEAVY METAL CONCENTRATION ON

      African Journals Online (AJOL)

      Temitope

      Index of geo-accumulation (Igeo), revealed no contamination of the trace metals. ... (Hg), arsenic (As) and cadmium (Cd). ... standards, and to suggest the best remedial methods ..... metal concentrations in urban soil of Ibadan metropolis,.

    7. Liquid metals: fundamentals and applications in chemistry.

      Science.gov (United States)

      Daeneke, T; Khoshmanesh, K; Mahmood, N; de Castro, I A; Esrafilzadeh, D; Barrow, S J; Dickey, M D; Kalantar-Zadeh, K

      2018-04-03

      Post-transition elements, together with zinc-group metals and their alloys belong to an emerging class of materials with fascinating characteristics originating from their simultaneous metallic and liquid natures. These metals and alloys are characterised by having low melting points (i.e. between room temperature and 300 °C), making their liquid state accessible to practical applications in various fields of physical chemistry and synthesis. These materials can offer extraordinary capabilities in the synthesis of new materials, catalysis and can also enable novel applications including microfluidics, flexible electronics and drug delivery. However, surprisingly liquid metals have been somewhat neglected by the wider research community. In this review, we provide a comprehensive overview of the fundamentals underlying liquid metal research, including liquid metal synthesis, surface functionalisation and liquid metal enabled chemistry. Furthermore, we discuss phenomena that warrant further investigations in relevant fields and outline how liquid metals can contribute to exciting future applications.

    8. Metal Ion Controlled Polymorphism of a Peptide

      DEFF Research Database (Denmark)

      Hemmingsen, Lars Bo Stegeager; Jancso, Attila; Szunyogh, Daniel

      2011-01-01

      ions on fully or partially unstructured proteins, or the effect of metal ions on protein aggregation. Metal ions may be employed to fold (or misfold) individual peptides in a controlled manner depending on the potential metal ion coordinating amino acid side chains (Cys, His, Asp, Glu......In this work a metal ion binding model dodecapeptide was investigated in terms of its capacity to adopt different structures depending on the metal ion to peptide stoichiometry. The dodecapeptide is much simpler than real proteins, yet displays sufficient complexity to model the effect of metal......, …) in the peptide, and the ligand and structural preferences of the metal ion (in our studies Zn2+, Cd2+, Hg2+, Cu+/2+). Simultaneously, new species such as metal ion bridged ternary complexes or even oligomers may be formed. In recent previous studies we have observed similar polymorphism of zinc finger model...

    9. Evolution of the liquid metal reactor

      International Nuclear Information System (INIS)

      Till, C.E.; Chang, Y.I.

      1989-01-01

      This paper reports on the integral fat reactor (IFR) concept. A key feature of the IFR concept is the metallic fuel, the original choice in liquid metal reactor development. An IFR development program is detailed by the authors

    10. Trace Metals Bioaccumulation Potentials of Three Indigenous ...

      African Journals Online (AJOL)

      User

      grasses as bioaccumulators of trace metals from polluted soils. Seeds of ... transfer factor (TF) showed that Zn was the most bioaccumulated trace metals by all the grasses followed by. Pb, Mn ... was used to de-contaminate copper (Cu) and.

    11. Method to synthesize metal chalcogenide monolayer nanomaterials

      Science.gov (United States)

      Hernandez-Sanchez, Bernadette A.; Boyle, Timothy J.

      2016-12-13

      Metal chalcogenide monolayer nanomaterials can be synthesized from metal alkoxide precursors by solution precipitation or solvothermal processing. The synthesis routes are more scalable, less complex and easier to implement than other synthesis routes.

    12. Process for making rare earth metal chlorides

      International Nuclear Information System (INIS)

      Kruesi, P.R.

      1981-01-01

      An uncombined metal or a metal compound such as a sulfide, oxide, carbonate or sulfate is converted in a liquid salt bath to the corresponding metal chloride by reacting it with chlorine gas or a chlorine donor. The process applies to metals of groups 1b, 2a, 2b, 3a, 3b, 4a, 5a and 8 of the periodic table and to the rare earth metals. The chlorine donor may be ferric or sulfur chloride. The liquid fused salt bath is made up of chlorides of alkali metals, alkaline earth metals, ammonia, zinc and ferric iron. Because the formed metal chlorides are soluble in the liquid fused salt bath, they can be recovered by various conventional means

    13. Gas adsorption on metal-organic frameworks

      Science.gov (United States)

      Willis, Richard R [Cary, IL; Low, John J. , Faheem, Syed A.; Benin, Annabelle I [Oak Forest, IL; Snurr, Randall Q [Evanston, IL; Yazaydin, Ahmet Ozgur [Evanston, IL

      2012-07-24

      The present invention involves the use of certain metal organic frameworks that have been treated with water or another metal titrant in the storage of carbon dioxide. The capacity of these frameworks is significantly increased through this treatment.

    14. Method of making alkali metal hydrides

      Science.gov (United States)

      Pecharsky, Vitalij K.; Gupta, Shalabh; Pruski, Marek; Hlova, Ihor; Castle, Andra

      2017-05-30

      A method is provided for making alkali metal hydrides by mechanochemically reacting alkali metal and hydrogen gas under mild temperature (e.g room temperature) and hydrogen pressure conditions without the need for catalyst, solvent, and intentional heating or cooling.

    15. A 75 GHz silicon metal-semiconductor-metal Schottky photodiode

      International Nuclear Information System (INIS)

      Alexandrou, S.; Wang, C.; Hsiang, T.Y.; Liu, M.Y.; Chou, S.Y.

      1993-01-01

      The ultrafast characteristics of crystalline-silicon metal-semiconductor-metal (MSM) photodiodes with 300 nm finger width and spacing were measured with a subpicosecond electro-optic sampling system. Electrical responses with full width at half maximum as short as 5.5 and 11 ps, at corresponding 3 dB bandwidths of 75 and 38 GHz, were generated by violet and red photons, respectively. The difference is attributed to the photon penetration depth which is much larger than the diode finger spacing at red, but smaller at violet. Light-intensity dependence was also examined at different wavelengths, indicating a linear relation and a higher sensitivity in the violet. These results not only demonstrated the fastest silicon photodetector reported to date, but also pinpointed the dominant speed-limiting factor of silicon MSM photodiodes. A configuration is suggested to improve the speed of these detectors at long wavelengths

    16. Electronic transport properties of carbon nanotube metal-semiconductor-metal

      Directory of Open Access Journals (Sweden)

      F Khoeini

      2008-07-01

      Full Text Available  In this work, we study electronic transport properties of a quasi-one dimensional pure semi-conducting Zigzag Carbon Nanotube (CNT attached to semi-infinite clean metallic Zigzag CNT leads, taking into account the influence of topological defect in junctions. This structure may behave like a field effect transistor. The calculations are based on the tight-binding model and Green’s function method, in which the local density of states(LDOS in the metallic section to semi-conducting section, and muli-channel conductance of the system are calculated in the coherent and linear response regime, numerically. Also we have introduced a circuit model for the system and investigated its current. The theoretical results obtained, can be a base, for developments in designing nano-electronic devices.

    17. Radiation effects in fine metal media

      International Nuclear Information System (INIS)

      Zaikin, Yu. A.; Aliev, A.B.

      1999-01-01

      The report discusses condition and perspectives of theoretical and experimental research of metal powder material radiation processing influence on their caking, recrystallization and formation of metal and alloy structure obtained by powder metallurgy methods. Radiation processing of metal powders under determined modes causes forming of homogeneous fine metal structure and helps to considerably improve their running abilities (strength, endurance, corrosion resistance) and caking technological conditions

    18. Casimir Repulsion between Metallic Objects in Vacuum

      International Nuclear Information System (INIS)

      Levin, Michael; McCauley, Alexander P.; Rodriguez, Alejandro W.; Reid, M. T. Homer; Johnson, Steven G.

      2010-01-01

      We give an example of a geometry in which two metallic objects in vacuum experience a repulsive Casimir force. The geometry consists of an elongated metal particle centered above a metal plate with a hole. We prove that this geometry has a repulsive regime using a symmetry argument and confirm it with numerical calculations for both perfect and realistic metals. The system does not support stable levitation, as the particle is unstable to displacements away from the symmetry axis.

    19. Bi-metallic nanoparticles as cathode electrocatalysts

      Science.gov (United States)

      Lu, Jun; Amine, Khalil; Wang, Xiaoping; Luo, Xiangyi; Myers, Deborah J.

      2018-03-27

      A lithium-air battery cathode catalyst includes core-shell nanoparticles on a carbon support, wherein: a core of the core-shell nanoparticles is platinum metal; and a shell of the core-shell nanoparticles is copper metal; wherein: the core-shell nanoparticles have a weight ratio of the copper metal to the platinum metal from about 4% to about 6% copper to from about 2% to about 12% platinum, with a remaining percentage being the carbon support.

    20. Titanium metal obtention by fused salts electrolysis

      International Nuclear Information System (INIS)

      Perillo, P.M.; Ares, Osvaldo; Botbol, Jose.

      1989-01-01

      Potassium fluorotitanate dissolved in fused sodium chloride or potassium chloride may be electrolyzed under an inert gas atmosphere. Solid electrolysis products are formed on the cathode which contains titanium metal, sodium chloride, lower fluorotitanates and small quantities of alkali metal fluorotitanate. The extraction of titanium from the electrolysis products may be carried out by aqueous leaching (removal of chloride salts of alkali metals and a certain amount of fluorotitanates). Titanium metal obtained is relatively pure. (Author)

    1. Fabrication of integrated metallic MEMS devices

      DEFF Research Database (Denmark)

      Yalcinkaya, Arda Deniz; Ravnkilde, Jan Tue; Hansen, Ole

      2002-01-01

      A simple and complementary metal oxide semiconductor (CMOS) compatible fabrication technique for microelectromechanical (MEMS) devices is presented. The fabrication technology makes use of electroplated metal layers. Among the fabricated devices, high quality factor microresonators are characteri......A simple and complementary metal oxide semiconductor (CMOS) compatible fabrication technique for microelectromechanical (MEMS) devices is presented. The fabrication technology makes use of electroplated metal layers. Among the fabricated devices, high quality factor microresonators...

    2. Ordered metal nanotube arrays fabricated by PVD.

      Science.gov (United States)

      Marquez, F; Morant, C; Campo, T; Sanz, J M; Elizalde, E

      2010-02-01

      In this work we report a simple method to fabricate ordered arrays of metal nanotubes. This method is based on the deposition of a metal by PVD onto an anodized aluminum oxide (AAO) template. The dimensions of the synthesized nanotubes depend both on the AAO template and on the deposited metal. In fact, it is observed that the aspect ratios of the nanotubes clearly depend significantly on the metal, ranging from 0.6 (Fe) to at least 3 (Zr).

    3. Thermal conductivity of molten metals

      Energy Technology Data Exchange (ETDEWEB)

      Peralta-Martinez, Maria Vita

      2000-02-01

      A new instrument for the measurement of the thermal conductivity of molten metals has been designed, built and commissioned. The apparatus is based on the transient hot-wire technique and it is intended for operation over a wide range of temperatures, from ambient up to 1200 K, with an accuracy approaching 2%. In its present form the instrument operates up to 750 K. The construction of the apparatus involved four different stages, first, the design and construction of the sensor and second, the construction of an electronic system for the measurement and storage of data. The third stage was the design and instrumentation of the high temperature furnace for the melting and temperature control of the sample, and finally, an algorithm was developed for the extraction of the thermal conductivity from the raw measurement data. The sensor consists of a cylindrical platinum-wire symmetrically sandwiched between two rectangular plane sheets of alumina. The rectangular sensor is immersed in the molten metal of interest and a voltage step is applied to the ends of the platinum wire to induce heat dissipation and a consequent temperature rise which, is in part, determined by the thermal conductivity of the molten metal. The process is described by a set of partial differential equations and appropriate boundary conditions rather than an approximate analytical solution. An electronic bridge configuration was designed and constructed to perform the measurement of the resistance change of the platinum wire in the time range 20 {mu}s to 1 s. The resistance change is converted to temperature change by a suitable calibration. From these temperature measurements as a function of time the thermal conductivity of the molten metals has been deduced using the Finite Element Method for the solution of the working equations. This work has achieved its objective of improving the accuracy of the measurement of the thermal conductivity of molten metals from {+-}20% to {+-}2%. Measurements

    4. Impacts of metal and metal oxide nanoparticles on marine organisms

      International Nuclear Information System (INIS)

      Baker, Tony J.; Tyler, Charles R.; Galloway, Tamara S.

      2014-01-01

      Increasing use of metal and metal oxide nanoparticles [Me(O)NPs] in products means many will inevitably find their way into marine systems. Their likely fate here is sedimentation following hetero-aggregation with natural organic matter and/or free anions, putting benthic, sediment-dwelling and filter feeding organisms most at risk. In marine systems, Me(O)NPs can absorb to micro-organisms with potential for trophic transfer following consumption. Filter feeders, especially bivalves, accumulate Me(O)NPs through trapping them in mucus prior to ingestion. Benthic in-fauna may directly ingest sedimented Me(O)NPs. In fish, uptake is principally via the gut following drinking, whilst Me(O)NPs caught in gill mucus may affect respiratory processes and ion transport. Currently, environmentally-realistic Me(O)NP concentrations are unlikely to cause significant adverse acute health problems, however sub-lethal effects e.g. oxidative stresses have been noted in many organisms, often deriving from dissolution of Ag, Cu or Zn ions, and this could result in chronic health impacts. -- Highlights: • Nanoparticle (NP) use increasing, and NPs ultimately discharged to marine systems. • Metal ion dissolution from NPs causes oxidative stress at relevant concentrations. • Bioaccumulation and trophic transfer of NPs likely at all levels of marine food webs. • Biofilms and filter feeders are major NP accumulators, but many Classes lack study. • Current release levels unlikely to cause chronic damage, but may be a future issue. -- Exposure to metal (oxide) nanoparticles causes sub-lethal effects in marine organisms, the extent of which is related principally to the organisms' feeding regime, habitat and lifestyle

    5. Metal Droplet Formation in Gas Metal Arc Welding

      International Nuclear Information System (INIS)

      Haidar, J.

      2000-01-01

      A two-dimensional dynamic treatment has been developed for description of arc and electrode properties in gas metal arc welding (GMAW). The theory is a unified treatment of the arc the welding wire anode and the cathode, and includes a detailed account of sheath effects near the anode. The wire anode is included as a dynamic entity and the volume of fluid method is used to handle the movement of the free surface of the molten metal at the tip of the wire, accounting for effects of surface tension, inertia, gravity, arc pressure, viscous drag force of the plasma, magnetic forces and Marangoni effect, and also for the effects of wire feed rate in GMAW. Results of calculations made for a mild steel wire of diameter 0.16 cm are in good agreement with experimental measurements of droplet diameter and droplet detachment frequency at currents between 150 and 330 A, which includes the transition between ''globular'' and ''spray'' transfer. Quantitative predictions are also made of the amount of metal vapour that is generated from the welding droplets at the tip of the welding wire. (author)

    6. Superconducting Metallic Glass Transition-Edge-Sensors

      Science.gov (United States)

      Hays, Charles C. (Inventor)

      2013-01-01

      A superconducting metallic glass transition-edge sensor (MGTES) and a method for fabricating the MGTES are provided. A single-layer superconducting amorphous metal alloy is deposited on a substrate. The single-layer superconducting amorphous metal alloy is an absorber for the MGTES and is electrically connected to a circuit configured for readout and biasing to sense electromagnetic radiation.

    7. PREPARATIONS AND APPLICATION OF METAL NANOPARTICLES

      OpenAIRE

      Adlim, Adlim

      2010-01-01

      Terminology of metal nanoparticles, the uniqueness properties in terms of the surface atom, the quantum dot, and the magnetism are described. The further elaboration was on the synthesis of nanoparticles. Applications of metal nanoparticles in electronic, ceramic medical and catalysis were overviewed. The bibliography includes 81 references with 99% are journal articles.   Keywords: metal nanoparticles

    8. Novel non-platinum metal catalyst material

      DEFF Research Database (Denmark)

      2014-01-01

      The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

    9. PREPARATIONS AND APPLICATION OF METAL NANOPARTICLES

      Directory of Open Access Journals (Sweden)

      Adlim Adlim

      2010-06-01

      Full Text Available Terminology of metal nanoparticles, the uniqueness properties in terms of the surface atom, the quantum dot, and the magnetism are described. The further elaboration was on the synthesis of nanoparticles. Applications of metal nanoparticles in electronic, ceramic medical and catalysis were overviewed. The bibliography includes 81 references with 99% are journal articles.   Keywords: metal nanoparticles

    10. A Study on Graphene—Metal Contact

      Directory of Open Access Journals (Sweden)

      Hongyu Yu

      2013-03-01

      Full Text Available The contact resistance between graphene and metal electrodes is crucial for the achievement of high-performance graphene devices. In this study, we review our recent study on the graphene–metal contact characteristics from the following viewpoints: (1 metal preparation method; (2 asymmetric conductance; (3 annealing effect; (4 interfaces impact.

    11. Ammonia release method for depositing metal oxides

      Energy Technology Data Exchange (ETDEWEB)

      Silver, G.L.; Martin, F.S.

      1993-12-31

      A method of depositing metal oxides on substrates which is indifferent to the electrochemical properties of the substrates and which comprises forming ammine complexes containing metal ions and thereafter effecting removal of ammonia from the ammine complexes so as to permit slow precipitation and deposition of metal oxide on the substrates.

    12. Combustion of metals, prevention and fire fighting

      International Nuclear Information System (INIS)

      Mellottee, H.

      1991-01-01

      The paper reviews the knowledge on metal combustion. Few works are devoted on metals such as magnesium or titanium. On the contrary liquid metals used as coolants, especially sodium, are much more studied. Results obtained on pool fires and spray fires are briefly given for global safety analysis of LMFBR. 11 refs

    13. Recycling of nonferrous metals from waste materials

      Energy Technology Data Exchange (ETDEWEB)

      Urban, A

      1982-02-01

      Recycling of metals was one of the 9 central subjects of the international symposium on 'Materials and Energy from Refuse', held in Antwerpen on October 20 to 22, 1981. Six of 65 poster sessions papers were on metal recycling; four of them discussed the recycling of nonferrous metals.

    14. A new lubricant carrier for metal forming

      DEFF Research Database (Denmark)

      Arentoft, Mogens; Bay, Niels; Tang, Peter Torben

      2009-01-01

      A lubricant carrier for metal forming processes is developed. Surfaces with pores of micrometer size for entrapping lubricant are generated by electrochemical deposition of an alloy, consisting of two immiscible metals, of which one metal subsequently is etched away leaving 5 mu m layers with a s...... extrusion at high reduction and excessive stroke comparing with conventionally lubrication using phosphate coating and soap....

    15. TREATMENT OF METALS PRIOR TO ELECTROPLATING

      Science.gov (United States)

      Huddle, R.A.U.; Flint, O.

      1958-05-20

      The preparation of certain metal surfaces to receive electrodeposits is described. Surfaces of the metals are subjected to shot blasting by ferrous metal shot, and the surfaces then are given a coating of copper by displacement from a copper salt solution. The method applies to U, Zr, Ti, Ta, Ni, Mo, W, and V.

    16. Regularities of changes of metal melting entropy

      International Nuclear Information System (INIS)

      Kats, S.A.; Chekhovskoj, V.Ya.

      1980-01-01

      Most trustworthy data on temperatures, heats and entropies of fusion of metals have been used as a basis to throw light on the laws governing variations of the entropy of metals fusion. The elaborated procedure is used to predict the entropies of the metals fusion whose thermodynamic properties under high temperatures have not yet been investigated

    17. Superconducting state parameters of ternary metallic glasses

      Indian Academy of Sciences (India)

      Administrator

      to binary metallic glasses. They are of interest since third element can modify the physical properties of binary metallic glasses and can also be used as a probe to study the host. ..... conducting nature in the present case. When we. Figure 6. Variation of transition temperature (TC) with valance (Z) of ternary metallic glasses.

    18. Specificity in liquid metal induced embrittlement

      CSIR Research Space (South Africa)

      Fernandes, PJL

      1996-12-01

      Full Text Available One of the most intriguing features of liquid metal induced embrittlement (LMIE) is the observation that some liquid metal-solid metal couples are susceptible to embrittlement, while others appear to be immune. This is referred to as the specificity...

    19. Liquid Metal Engineering and Technology. Volume 1

      International Nuclear Information System (INIS)

      1988-01-01

      These proceedings of the fourth international conference on liquid metal engineering and technology volume 1, are devided into 3 sections bearing on: - Apparatus and components for liquid metal (29 papers) - Liquid metal leaks, fires and fumes (10 papers) - Cleaning, decontamination, waste disposal (14 papers) [fr

    20. Thin films of mixed metal compounds

      Science.gov (United States)

      Mickelsen, Reid A.; Chen, Wen S.

      1985-01-01

      A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.