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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. Diseño de un sistema de descanso a partir del reproceso del poliestireno expandido industrial desechado

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    Urrea Restrepo, Alejandra

    2009-01-01

    Una de las problemáticas ambientales que se viven actualmente es el gran número desechos sólidos que se generan a diario, uno de estos desechos es el poliestireno expandido (su siglas en ingles EPS) o icopor como es conocido en Colombia. Actualmente se conoce que una de las industrias donde se emplea a gran escala este material es en la construcción y el embalaje, por lo que se produce, se usa y se desecha rápidamente, contando con un ciclo de vida corto e impactante para el medio ambiente, d...

  3. Evaluación de la producción de pintura a partir de los residuos de Poliestireno expandido utilizando un solvente amigable con el ambiente

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    Arcila Arcila, Isabel Cristina; Miranda Giraldo, Juliana

    2016-01-01

    Con la evaluación de la producción de pintura a partir de los residuos de poliestireno expandido (EPS) utilizando un solvente amigable con el ambiente, se pretende dar uso post industrial a los desechos de poliestireno expandido que cada vez se acumulan más en los rellenos sanitarios, lo que genera un descontento debido a su volumen -- Además de darle un trato más amigable a la fabricación de pintura buscando un solvente que no resulte tan tóxico para el trato humano y para el ambiente -- El ...

  4. 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.

  5. 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...

  6. Comportamento do consumidor da Comunidade de Marca Harley-Davidson e a influência do self-expandido

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    Edna de Souza Machado Santos

    2017-03-01

    Full Text Available Esta pesquisa tem por objetivo avaliar a influência das atitudes e desejos sobre self-expandido e este sobre o comportamento do consumidor na comunidade de marca Harley-Davidson. A relevância deste estudo aponta para o fato de que as comunidades de marca representam papel fundamental de estudo para a área de marketing no Brasil, pois oferecem condições para se investigar e compreender, com mais profundidade, aspectos relacionados ao comportamento do consumidor, a compreensão sobre a influência e o tipo de cultura que o consumidor brasileiro recebe no que se refere à Brand equity (ATKIN, 2007; YOO & DONTHU, 2001; AAKER, 1998. O corpus da pesquisa contou com uma survey com 193 participantes de comunidades de marca. A abordagem metodológica utilizada foi quantitativa com a utilização do SmartPLS para análise dos dados. Os resultados obtidos mostram que as relações intergrupais, no que tange às atitudes, desejos e emoções positivas, são sentimentos compartilhados e que ampliam o desejo em participar das atividades dessa comunidade de marca, o que culmina com a expansão do self do participante da comunidade Harley-Davidson, pelo comportamento de grupo (pertencimento, pela interação social (envolvimento, identidade social e comportamento com a marca. 

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

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    Roderick Peter Steel

    2014-12-01

    Full Text Available Esta pesquisa apresenta uma produção autoral e reflexão crítica sobre registros de experiências e relatos documentais em imagens para evidenciar como as novas tecnologias modificam a prática religiosa. Propósitos de refletir sobre imagens sagradas do candomblé quando transitam entre meios audiovisuais e seus processos. A pesquisa objetiva seguir trajetórias de registros do corpo humano em transe, por diferentes dispositivos em diversos meios eletrônicos, para reuni-los em um documentário expandido em múltiplas telas dentro de uma instalação. O estudo examina as fronteiras entre o registro documental do evento religioso e sua reconstrução dentro do espaço expositivo, criando teias de relações entre as linguagens do cinema, fotografia, artes visuais e antropologia em espaços arquitetônicos complexos para potencializar uma experiência imersiva e sensorial.

  8. 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

  9. 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.

  10. 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

  11. Estudio de la superficie de limas de endodoncia sometidas a desinfección química mediante microscopia electrónica de barrido

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    Navarro Majó, G.; Mateos, M.; Navarro, J.L.; Canalda Sahli, Carlos

    1991-01-01

    Se observaron al microscopio electró nico de barrido 40 limas de endodoncia de acero inoxidable después de ser sometidas a 10 ciclos de desinfección de 10 minutos cada ciclo, sumergidas en diferentes desinfectantes químicos. No se observó corrosión en la superficie de las limas en las circunstancias en que se realizó ese estudio.

  12. 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.

  13. 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.

  14. Doblemente sometidas: las «mujeres de color» en la república de Cuba (1902-1959

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    Ramírez Chicharro, Manuel

    2014-12-01

    Full Text Available This study analyzes the development of afro-descendant women during the Republic of Cuba (1902-1959. First of all, works dedicated to Cuban women as a gender are assessed on one hand and to Afro culture on the other in order to show the extent to which Afro-Cuban women have been neglected by historiography. Then black and mixed-race women are studied in relation to the entire male population and white women. The text is divided into three parts: educational areas, vocational integration and political mobility. The data enables us to affirm that Afro-Cuban women were doubly subjugated throughout the Republican period, because of their gender against men, and because of race against white women.El estudio analiza la trayectoria de las mujeres afrodescendientes durante la República de Cuba (1902-1959. En primer lugar, se realiza una valoración de las obras dedicadas a las mujeres cubanas como género, por un lado, y a la cultura afro, por otro, para demostrar hasta qué punto las mujeres afrocubanas han sido desatendidas por la historiografía. Después se pasa a examinar a las mujeres negras y mestizas en relación con la población masculina total y las mujeres blancas. El texto se divide en tres apartados: campo educativo, inserción laboral y movilidad política. Los datos permiten afirmar que las mujeres afrocubanas estuvieron doblemente sometidas durante todo el período republicano, por género frente a los hombres negros, por «raza» frente a las mujeres blancas.

  15. 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

  16. 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”.

  17. Seroconversión reversa y hepatitis B fulminante en paciente sometida a tratamiento quimioterápico por Linfoma no Hodgkina

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    Milagros Bécares Lozano

    2013-01-01

    RESUMEN La pérdida de HBsAg en la hepatitis B aguda indica buen pronóstico, si bien el virus puede permanecer en el hígado con bajos niveles de DNA y HBcAc (+). El tratamiento inmunosupresor induce reactivación viral en estos pacientes, sobre todo el Rituximab y los corticoides, dando lugar a la reaparición de HBsAg en el llamado fenómeno de seroconversión reversa. Presentamos una paciente portadora de HBsAg (-), HBsAc (+) y HBcAc (+), sometida a tratamiento inmunosupresor por presenta...

  18. Factores que afectan la preñez en vacas Brahman sometidas a inseminación artificial a tiempo fijo

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    Adriana Correa-Orozco; Luis Uribe-Velásquez; Erik Pulgarín-Velásquez

    2013-01-01

    RESUMENObjetivo. Evaluar la relación entre la condición corporal (CC), la manifestación de estro, las concentraciones plasmáticas de estradiol, el diámetro del folículo mayor y la preñez, en vacas Bos indicus amamantando, sometidas a un protocolo de inseminación artificial a tiempo fijo (IATF). Materiales y métodos. Treinta y ocho vacas Brahman recibieron un dispositivo intravaginal de progesterona + benzoato de estradiol en el día 0; retiro del dispositivo + dinoprost + gonadotropina corióni...

  19. Calidad de vida relacionada con la salud en pacientes con cáncer de mama sometidas a linfadenectomia axilar y en pacientes con linfedema tras tratamiento quirúrgico por cáncer de mama

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    Belmonte Martínez, Roser

    2012-01-01

    El impacto de la linfadenectomía axilar en la calidad de vida de las pacientes con cáncer de mama no se ha demostrado de manera concluyente. Por otro lado, se ha constatado que no hay suficientes estudios sobre la calidad de vida de estas pacientes en nuestro medio. El objetivo principal de este estudio fue comparar la calidad de vida de las pacientes con cáncer de mama sometidas a linfadenectomia axilar (LA), con las pacientes sometidas a biopsia selectiva del ganglio centinela (BSGC), utili...

  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

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    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. Factores que afectan la preñez en vacas Brahman sometidas a inseminación artificial a tiempo fijo

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    Adriana Correa-Orozco

    2013-03-01

    Full Text Available Objetivo. Evaluar la relación entre la condición corporal (CC, la manifestación de estro, las concentraciones plasmáticas de estradiol, el diámetro del folículo mayor y la preñez, en vacas Bos indicus amamantando, sometidas a un protocolo de inseminación artificial a tiempo fijo (IATF. Materiales y métodos. Treinta y ocho vacas Brahman recibieron un dispositivo intravaginal de progesterona + benzoato de estradiol en el día 0; retiro del dispositivo + dinoprost + gonadotropina coriónica equina en el día 9 y la IATF en el día 12. La preñez fue diagnosticada 90 días después de la IATF. Resultados. No hubo efecto de la CC sobre la manifestación de estro, las concentraciones plasmáticas de estradiol o el diámetro del folículo mayor (p>0.05. El diámetro del folículo mayor no influenció las concentraciones plasmáticas de estradiol (p>0.05. El diámetro del folículo mayor y las concentraciones plasmáticas de estradiol no influenciaron la manifestación de estro (p>0.05. La tasa de preñez por IATF no fue afectada (p>0.05 por la CC, la manifestación de estro o las concentraciones plasmáticas de estradiol. Hubo una tendencia (p=0.10 de una relación directa entre el diámetro del folículo mayor y la tasa de preñez por IATF. Conclusiones. La CC, las concentraciones plasmáticas de estradiol y la manifestación de estro no influenciaron la tasa de preñez por IATF en vacas Brahman sometidas a un protocolo de sincronización basado en progesterona. Sin embargo, el diámetro del folículo mayor presentó tendencia al impacto positivo sobre la tasa de preñez por IATF.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Seroconversión reversa y hepatitis B fulminante en paciente sometida a tratamiento quimioterápico por Linfoma no Hodgkina

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    Milagros Bécares Lozano

    2013-12-01

    Presentamos una paciente portadora de HBsAg (-, HBsAc (+ y HBcAc (+, sometida a tratamiento inmunosupresor por presentar un LNH-B de células grandes. La ausencia de profilaxis con nucleósidos/nucleótidos precipitó la replicación de VHB con desarrollo de hepatitis aguda seguida de hepatitis fulminante y exitus. Se realiza revisión de la literatura al respecto. ABSTRACT Loss of HBsAg in acute Hepatitis B is a sign of good prognosis ,though the virus can remain in the liver in the presence of HBc Ac and low serum levels of HBV DNA. However immunosuppressive therapy can induce viral reactivation in these patients, mainly when rituximab and or corticosteroids are administered ,with subsequent reappearance of HBs Ag (reverse seroconversion.Here we report a case of a B-cell non Hodgkin lymphoma female patient who was negative for HBs Ag but positive for both HBs Ac and HBc Ac just at the time of therapy. Lack of prophylactic treatment with nucleotide/nucleoside analogues allowed the development of acute HBV reactivation and fulminant hepatitis. A review of scientific literature is also included.

  5. 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.

  6. Application of expanded inert polytetrafluorethylene membrane in prevention of post laminectomy fibrosis in wistar rats Estudo do uso da membrana de politetrafluoroetileno inerte expandido para a prevenção da fibrose pós laminectomia em ratos wistar

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    Tarcísio Eloy Pessoa Barros Filho

    2003-04-01

    Full Text Available Post laminectomy fibrosis in spine surgery has been responsible for a high rate of failure in a short or long term. Many of this patients develop chronic or recurrent pain after surgery of discal herniation, canal stenosis etc. Although there some doubts about the etiology of this problem, it was known that fibrosis interfere with the normal mobility of roots and spinal cord. This factor is considered as the most important aspect in the genesis of the surgical failures. To avoid postoperative fibrosis, a lot of materials of interposition between posterior spine muscles and dura mater were studied, without good response. This paper studied comparatively post laminectomy fibrosis in Wistar rats with the addition of the following materials to avoid it: control group (without interposition and expanded inert polytetrafluoroethylene membrane (Preclude Spinal Membrane®. It was observed that accurate surgical technique apparently is an important factor to prevent the formation of abundant scar tissue and that the expanded inert polytetrafluoroethylene membrane is an inert material.A fibrose pós laminectomia em cirurgias da coluna vertebral tem sido responsabilizada por um grande percentual das falhas nestas cirurgias, tanto a curto quanto a longo prazo. Muitos dos pacientes desenvolvem sintomas de dor crônica ou recorrente após tratamento cirúrgico de hérnias de disco, estenose de canal, etc. Apesar de ainda existirem dúvidas quanto à fisiopatologia do problema, sabe-se que a fibrose interfere na mobilidade normal das raízes e da medula espinal, fator este responsabilizado como o principal na gênese das falhas cirúrgicas. Para se evitar a fibrose pós-cirúrgica, vários materiais de interposição entre a musculatura posterior da coluna e a dura-máter foram estudados, sem grandes resultados. Neste trabalho foi feito o estudo da membrana de politetrafluoroetileno inerte expandido (Preclude Spinal Membrane® comparando-se a mesma com grupo

  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

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    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. 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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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.

  11. Extended-spectrum beta-lactamase production among ampicillin-resistant Escherichia coli strains from chicken in Enugu State, Nigeria Produção de beta-lactamase de espectro expandido por cepas de Escherichia coli resistentes a ampicilina isoladas de frango em Enugu State, Nigéria

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    K.F. Chah

    2007-12-01

    Full Text Available One hundred and seventy-two ampicillin-resistant E. coli strains isolated from commercial chickens in Enugu State, Nigeria, were screened for beta-lactamase production using the broth method with nitrocefin® as the chromogenic cephalosporin to detect enzyme production. Beta-lactamase producing strains were further examined for extended-spectrum beta-lactamase (ESBL production using the Oxoid combination discs method. One hundred and seventy (98.8% of the 172 ampicillin-resistant E. coli strains produced beta-lactamase enzyme. Sixteen (9.4% beta-lactamase producers were phenotypically confirmed to produce ESBLs. Six of the ESBL producing strains were only detected with ceftazidime versus ceftazidime/clavulanate combination while ten of the ESBL producers were detected with cefotaxime versus cefotaxime/clavulanate combination. Chicken may serve as a reservoir of ESBL-producing E. coli strains which could be transferred to man and other animals.Cento e setenta e duas cepas de Escherichia coli resistentes a ampicilina isoladas de frangos em Enugu State, Nigéria, foram avaliadas quanto à produção de beta-lactamase através do uso de método em caldo com nitrocefin® como indicador cromogênico da produção da enzima. Em seguida, as cepas produtoras de beta-lactamase foram examinadas quanto à produção de beta-lactamase de espectro expandido (ESBL através do método de discos combinados Oxoid. Entre as cepas de Escherichia coli resistentes a ampicilina, cento e setenta (98,8% produziram beta-lactamase. Testes fenotípicos indicaram que dezesseis (9,4% das cepas produtoras de beta-lactamase produziram ESBL. Seis cepas produtoras de ESBL foram detectadas apenas com a combinação ceftazidima versus cefotaxime/clavulanato, enquanto dez cepas produtoras de ESBL foram detectadas com a combinação cefotaxime versus cefotaxime/clavulanato. Frangos podem ser reservatório de cepas de E.coli produtoras de ESBL, que podem ser transferidos para o homem

  12. 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...

  13. 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

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    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

  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

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    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. Metallated metal-organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-07

    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.

  16. 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.

  17. 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

  18. 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

  19. 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......M hip implant. A Danish surveillance programme has been initiated addressing these problems....

  20. ESTUDO DA VIABIBILIDADE DO EMPREGO DE PÓ DE MÁRMORE PARA PRODUÇÃO DE CONCRETO AUTO-ADENSÁVEL E SUBSTITUIÇÃO PARCIAL DOS AGREGADOS POR PÉROLAS DE POLIESTIRENO EXPANDIDO (EPS (doi:10.5216/reec.V10i2.33117

    Directory of Open Access Journals (Sweden)

    Rosemarie Kumayama

    2015-09-01

    Full Text Available RESUMO: Este trabalho estuda a viabilidade técnica da utilização do pó de mármore como finos na confecção de concreto autoadensável (CAA, juntamente com a substituição de parte dos agregados graúdos e miúdos por poliestireno expandido (EPS. Adotando a relação fíler-cimento igual a 0,15, foi otimizada uma composição de referência sem a substituição de EPS, e para fins de comparação foram otimizadas composições com substituição, adotando-se as porcentagens de 10%, 20%, 30% e 40% em substituição. Alguns ensaios foram realizados no estado fresco para fins da validação do CAA, e no estado endurecido para a avaliação do desempenho em função das substituições. Os ensaios no estado fresco incluíam os seguintes: Slump Flow Test, Slump Flow T50 Test, V- Funnel Test, L- Box Test, Ensaio de Peneiramento, e Ensaio da Massa Específica Aparente. No estado endurecido foram realizados os ensaios de avaliação da resistência à compressão simples e da resistência à compressão diametral, além dos ensaios de absorção d’água. Dos ensaios no estado fresco observou-se influencias no sentido de que a incorporação gradativa de isopor junto ao pó de mármore contribuiu para o aumento dos valores das propriedades que dependem da viscosidade do concreto, de modo a minimizar os efeitos de segregação e de exsudação, compensado a baixa retenção de água pelo pó de mármore. Os resultados no estado fresco se apresentaram de modo a validar as propriedades requeridas para o CAA. No estado endurecido observou-se a diminuição dos valores de resistência à compressão simples e diametral, e o aumento dos valores da absorção, com o incremento do teor de EPS em substituição. Percebeu-se que a variação dos valores das propriedades mecânicas se deu de modo aproximadamente linear, oferecendo o indicativo de um modelo previsional para a variação do comportamento mecânico, quando considerado o teor de EPS adotado em

  1. 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.)

  2. Evaluación del efecto analgésico postoperatorio de infusiones intraoperatorias de tramadol y tramadol/lidocaína/ketamina en comparación con morfina/lidocaína/ketamina en hembras caninas sometidas a ovariohisterectomía Evaluation of postoperative analgesic effect of intraoperative infusions of tramadol and tramadol/lidocaine/ketamine compared with morphine/lidocaine/ketamine in female dogs undergoing ovariohysterectomy

    OpenAIRE

    MA Fajardo; MA Lesmes; LA Cardona

    2012-01-01

    El objetivo de este estudio fue evaluar y comparar la eficacia analgésica postoperatoria de infusiones intraoperatorias de tramadol y tramadol/lidocaína/ketamina en comparación con morfina/lidocaína/ketamina en hembras caninas sometidas a ovariohisterectomía. Se usaron 30 hembras caninas sin distinción de raza con una edad entre 1 y 10 años y un peso entre 2,5 y 37 kilogramos, conformando tres grupos aleatorios de 10 animales cada uno: grupo tramadol, grupo tramadol/lidocaína/ ketamina y grup...

  3. Metal lagging

    International Nuclear Information System (INIS)

    Lemercier, Guy.

    1974-01-01

    The metal lagging described is characterized by the fact that it is formed of closed sacks composed of an elastic metal mass, compressed in an outer envelope made of a fine mesh metal fabric. The metal mass is composed of stainless steel wool stuffed into the envelope. This lagging is particularly intended for the thermal protection of the end slab of LMFBR type reactors [fr

  4. 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.

  5. 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.

  6. VLSI metallization

    CERN Document Server

    Einspruch, Norman G; Gildenblat, Gennady Sh

    1987-01-01

    VLSI Electronics Microstructure Science, Volume 15: VLSI Metallization discusses the various issues and problems related to VLSI metallization. It details the available solutions and presents emerging trends.This volume is comprised of 10 chapters. The two introductory chapters, Chapter 1 and 2 serve as general references for the electrical and metallurgical properties of thin conducting films. Subsequent chapters review the various aspects of VLSI metallization. The order of presentation has been chosen to follow the common processing sequence. In Chapter 3, some relevant metal deposition tec

  7. Heavy metal

    African Journals Online (AJOL)

    of spawning, resistance to diseases and social acceptability (Pillay, 1993). This study aimed at determining the carbohydrate reserves and heavy metal accumulation of the Nile tilapia, Oreochromis miloticus after treatment with heavy metals such as lead, copper and zinc. 2. Materials and Methods. Test organism: Nile tilapia ...

  8. 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)

  9. Metals 2000

    Energy Technology Data Exchange (ETDEWEB)

    Allison, S.W.; Rogers, L.C.; Slaughter, G. [Oak Ridge National Lab., TN (United States); Boensch, F.D. [6025 Oak Hill Lane, Centerville, OH (United States); Claus, R.O.; de Vries, M. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)

    1993-05-01

    This strategic planning exercise identified and characterized new and emerging advanced metallic technologies in the context of the drastic changes in global politics and decreasing fiscal resources. In consideration of a hierarchy of technology thrusts stated by various Department of Defense (DOD) spokesmen, and the need to find new and creative ways to acquire and organize programs within an evolving Wright Laboratory, five major candidate programs identified are: C-17 Flap, Transport Fuselage, Mach 5 Aircraft, 4.Fighter Structures, and 5. Missile Structures. These results were formed by extensive discussion with selected major contractors and other experts, and a survey of advanced metallic structure materials. Candidate structural applications with detailed metal structure descriptions bracket a wide variety of uses which warrant consideration for the suggested programs. An analysis on implementing smart skins and structures concepts is given from a metal structures perspective.

  10. Metal carbides

    International Nuclear Information System (INIS)

    Wells, A.F.

    1988-01-01

    From the viewpoint of general crystal chemistry principles and on the base of modern data the structural chemistry of metal carbides is presented. The classification deviding metal carbides into 4 groups depending on chemical and physical properties is presented. The features of the crystal structure of carbides of alkali alkaline earth, transition, 4 f- and 5f-elements and their effect on physical and chemical properties are considered

  11. metal alkoxides

    Indian Academy of Sciences (India)

    substituent effects in the head-to-tail double insertion reactions observed ... an internal standard. The yield of diphenyl carbodii- mide was further verified by isolating it as diphenyl urea after hydrolysis. The organic fraction obtained in the catalytic metathesis .... insertion of PhNCO into metal alkoxide 1a to generate. Table 1.

  12. Metallic glasses

    NARCIS (Netherlands)

    Schaafsma, Arjen Sybren

    1981-01-01

    It is shown in section 7.1. that the influence of topological disorder on the range of magnetic interactions in ferromagnetic transition metal-metalloid (TM-M) glasses, is much less than often assumed. This is demonstrated via a study of the temperature dependence of the average iron hyperfine field

  13. 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.

  14. 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

  • 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

  • Metal phosphides

    International Nuclear Information System (INIS)

    Uehlls, A.

    1987-01-01

    The structure of phosphides of the most of elements: alkali, alkaline earth, rare earth, transition metals, actinides, indium, beryllium, cadmium forming the variety of formulae and types of structures, is considered. The ways of P atom combination in phosphides vary from single atoms (ions P 3- in compounds of electropositive elements) through one-, two-dimensional complexes P n up to three-dimensional (charged) grids. In all phosphides, containing the systems of bound atoms of phosphorus, certain or all from these atoms form less than three bonds P-P. The formation of one bond P-P by every atom leads to group P 2 found as P 2 4- ion in diphosphides of transition metals with the structure of the pyrite or marcasite type (RuP 2 ). LaP, SmP, ThP, UP, ZrP form structural type NaCl

  • 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.

     

    O sentido da sexualidade de mulheres submetidas a histerectomia: uma contribuição da enfermagem para a integralidade da assistência ginecológica El sentido de la sexualidad de mujeres sometidas a histerectomia: una contribución de la enfermería a la integralidad de la asistencia ginecológica The meaning of women´s sexuality that were submited to the histerectomy: a nursing contribution for the completeness of the gynecological assistance

    Directory of Open Access Journals (Sweden)

    Anna Maria de Oliveira Salimena

    2008-12-01

    Full Text Available A histerectomia é um procedimento cirúrgico irreversível, realizado por indicação médica, com a finalidade de restabelecer a saúde ou mesmo salvar a vida da mulher. Ser submetida a esta cirurgia acarreta modificações em seu cotidiano porque as recomendações pertinentes ao pós-operatório de histerectomia impõem implicações em seu mundo-vida. Este estudo de natureza qualitativa teve como objetivo analisar o sentido da sexualidade de mulheres após a histerectomia à luz do pensamento de Martin Heidegger. Foram depoentes 25 mulheres submetidas à retirada total do útero; a entrevista fenomenológica ocorreu num tempo variado, de 4 a 19 meses após o procedimento cirúrgico. A interpretação da estrutura de significação "a atividade sexual foi considerada" desvelou que na dinâmica assistencial, médica e de enfermagem, as rotineiras orientações de abstinência sexual determinadas pelo pós-operatório devem ser consideradas a partir da subjetividade da mulher que será/foi submetida à histerectomia.La histerectomia es un procedimiento quirúrgico irreversible realizado por indicación médica con la finalidad de restablecer la salud o mismo salvar la vida de la mujer. Ser sometida a esta cirurgía acarrea modificaciones en su cotidiano porque las recomendaciones para después de una operación de histerectomia imponen implicaciones en su mundo-vida. Este estudio de naturaleza cualitativa tuvo como objetivo analizar el sentido de la sexualidad de mujeres tras la histerectomia a la luz del pensamiento de Martin Heidegger. Fueron oídas 25 mujeres sometidas a la retirada total de útero siendo que la encuesta fenomenológica ocurrió en un tiempo entre cuatro y diecinueve meses tras el procedimiento quirúrgico. La interpretación de la estructura de la significación "la actividad sexual fue considerada" enseñó que en la dinámica asistencial médica y de enfermería, las orientaciones de rutina de abstinencia sexual

  • 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.

  • Mechanochemical processing for metals and metal alloys

    Science.gov (United States)

    Froes, Francis H.; Eranezhuth, Baburaj G.; Prisbrey, Keith

    2001-01-01

    A set of processes for preparing metal powders, including metal alloy powders, by ambient temperature reduction of a reducible metal compound by a reactive metal or metal hydride through mechanochemical processing. The reduction process includes milling reactants to induce and complete the reduction reaction. The preferred reducing agents include magnesium and calcium hydride powders. A process of pre-milling magnesium as a reducing agent to increase the activity of the magnesium has been established as one part of the invention.

    1. Metal filled porous carbon

      Science.gov (United States)

      Gross, Adam F [Los Angeles, CA; Vajo, John J [West Hills, CA; Cumberland, Robert W [Malibu, CA; Liu, Ping [Irvine, CA; Salguero, Tina T [Encino, CA

      2011-03-22

      A porous carbon scaffold with a surface and pores, the porous carbon scaffold containing a primary metal and a secondary metal, where the primary metal is a metal that does not wet the surface of the pores of the carbon scaffold but wets the surface of the secondary metal, and the secondary metal is interspersed between the surface of the pores of the carbon scaffold and the primary metal.

    2. 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

    3. 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

    4. 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

    5. Neurotoxicity of metals.

      Science.gov (United States)

      Caito, Samuel; Aschner, Michael

      2015-01-01

      Metals are frequently used in industry and represent a major source of toxin exposure for workers. For this reason governmental agencies regulate the amount of metal exposure permissible for worker safety. While essential metals serve physiologic roles, metals pose significant health risks upon acute and chronic exposure to high levels. The central nervous system is particularly vulnerable to metals. The brain readily accumulates metals, which under physiologic conditions are incorporated into essential metalloproteins required for neuronal health and energy homeostasis. Severe consequences can arise from circumstances of excess essential metals or exposure to toxic nonessential metal. Herein, we discuss sources of occupational metal exposure, metal homeostasis in the human body, susceptibility of the nervous system to metals, detoxification, detection of metals in biologic samples, and chelation therapeutic strategies. The neurologic pathology and physiology following aluminum, arsenic, lead, manganese, mercury, and trimethyltin exposures are highlighted as classic examples of metal-induced neurotoxicity. © 2015 Elsevier B.V. All rights reserved.

    6. 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...

    7. Metal polish poisoning

      Science.gov (United States)

      Metal polishes are used to clean metals, including brass, copper, or silver. This article discusses the harmful effects from swallowing metal polish. This article is for information only. DO NOT use ...

    8. Metal-phosphate binders

      Science.gov (United States)

      Howe, Beth Ann [Lewistown, IL; Chaps-Cabrera, Jesus Guadalupe [Coahuila, MX

      2009-05-12

      A metal-phosphate binder is provided. The binder may include an aqueous phosphoric acid solution, a metal-cation donor including a metal other than aluminum, an aluminum-cation donor, and a non-carbohydrate electron donor.

    9. Comportamiento mecánico del poliestireno expandido (EPS) bajo carga de compresión /

      OpenAIRE

      Ossa López, Alexandra sustentante.

      2009-01-01

       tesis que para obtener el grado de Doctor en Ingeniería Civil, presenta Alexandra Ossa López ; asesor Miguel Pedro Romo Organista. vii, 79 páginas : ilustraciones. Doctorado en Ingeniería Civil UNAM, Instituto de Ingeniería, 2009

    10. Fragmentos expandidos para a reconstrução da Shoah

      Directory of Open Access Journals (Sweden)

      Larissa Vaz

      2015-05-01

      Full Text Available A Shoah em um romance de ficção põe em questão algumas fronteiras entre o literário e o fictício. Este artigo analisa o romance Tudo se ilumina, 2005, de Jonathan Safran Foer, verificando a utilização de recursos narrativos, como a lista e a enumeração como uma estratégia de expansão do fragmento da memória.

    11. Encofrado perdido constituido por paja cohesionada con micelio como sustituto del poliestireno expandido

      Directory of Open Access Journals (Sweden)

      Román-Ramos, J. D.

      2014-12-01

      Full Text Available This paper presents some of the physical and mechanical properties of a material made of mycelium within wheat straw. The aim of this study is to take advantage of the excellent properties of the cellular walls of fungi, made of chitin, an organic substance very abundant in the nature that presents notable mechanical properties both to compete with very contaminant plastics usually used in construction, like expanded polystyrene, and to substitute them, as this new material is biodegradable too. First simple compression essays carried out on the mentioned conglomerate made of mycelium within wheat straw provide promising mechanical strength results.En esta publicación se presentan algunas de las cualidades físicas y mecánicas de un material constituido por micelio sobre sustrato a base de paja de trigo. El objetivo es aprovechar las bondades de las paredes celulares del hongo, compuestas por quitina, una sustancia orgánica muy abundante en la naturaleza y que presenta unas excelentes propiedades mecánicas que convierten este material en idóneo, no sólo para competir con los contaminantes plásticos tan tradicionalmente empleados en construcción, tales como el poliestireno, sino para sustituirlos, puesto que el compuesto es totalmente biodegradable. Los primeros ensayos a compresión simple efectuados sobre este conglomerado formado por el sustrato y la quitina arrojan resultados de resistencia mecánica prometedores.

    12. 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.

    13. 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

    14. Metals and metal derivatives in medicine.

      Science.gov (United States)

      Colotti, Gianni; Ilari, Andrea; Boffi, Alberto; Morea, Veronica

      2013-02-01

      Several chemical elements are required by living organisms in addition to the four elements carbon, hydrogen, nitrogen and oxygen usually present in common organic molecules. Many metals (e.g. sodium, potassium, magnesium, calcium, iron, zinc, copper, manganese, chromium, molybdenum and selenium) are known to be required for normal biological functions in humans. Disorders of metal homeostasis and of metal bioavailability, or toxicity caused by metal excess, are responsible for a large number of human diseases. Metals are also extensively used in medicine as therapeutic and/or diagnostic agents. In the past 5000 years, metals such as arsenic, gold and iron have been used to treat a variety of human diseases. Nowadays, an ever-increasing number of metal-based drugs is available. These contain a broad spectrum of metals, many of which are not among those essential for humans, able to target proteins and/or DNA. This mini-review describes metal-containing compounds targeting DNA or proteins currently in use, or designed to be used, as therapeutics against cancer, arthritis, parasitic and other diseases, with a special focus on the available information, often provided by X-ray studies, about their mechanism of action at a molecular level. In addition, an overview of metal complexes used for diagnosing diseases is presented.

    15. 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...

    16. Glassy metallic plastics

      Science.gov (United States)

      Li, Jianfu; Wang, Junqiang; Liu, Xiaofeng; Zhao, Kun; Zhang, Bo; Bai, Haiyang; Pan, Mingxiang; Wang, Weihua

      2010-03-01

      This paper reports a class of bulk metallic glass including Ce-, LaCe-, CaLi-, Yb-, and Sr-based metallic glasses, which are regarded as glassy metallic plastics because they combine some unique properties of both plastics and metallic alloys. These glassy metallic plastics have very low glass transition temperature ( T g ˜25°C to 150°C) and low Young’s modulus (˜20 GPa to 35 GPa). Similar to glassy plastics, these metallic plastics show excellent plastic-like deformability on macro-, micro- and even nano-scale in their supercooled liquid range and can be processed, such as elongated, compressed, bent, and imprinted at low temperatures, in hot water for instance. Under ambient conditions, they display such metallic properties as high thermal and electric conductivities and excellent mechanical properties and other unique properties. The metallic plastics have potential applications and are also a model system for studying issues in glass physics.

    17. Metal phthalocyanine catalysts

      Science.gov (United States)

      Ellis, Jr., Paul E.; Lyons, James E.

      1994-01-01

      As a new composition of matter, alkali metal or ammonium or tetraalkylammonium diazidoperfluorophthalocyanatoferrate. Other embodiments of the invention comprise compositions wherein the metal of the coordination complex is cobalt, manganese and chromium.

    18. 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...... 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....

    19. 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....

    20. 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.

    1. Novel Ammonium Metal Borohydrides

      DEFF Research Database (Denmark)

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

      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...

    2. Multiple allergies to metal alloys

      Directory of Open Access Journals (Sweden)

      Mei-Eng Tu

      2011-06-01

      Conclusions: Metal alloys may induce multiple metal allergies. Patients suspected of having a metal allergy should be patch tested with an extended series of metals. We recommend adding palladium and gold, at least, to the standard series.

    3. Conducting metal oxide and metal nitride nanoparticles

      Energy Technology Data Exchange (ETDEWEB)

      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.

    4. 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

    5. 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....

    6. Metal Detecting in Denmark

      DEFF Research Database (Denmark)

      Dobat, A.S.

      2016-01-01

      Since the early 1980s, metal detector surveying conducted by non-professional volunteers (amateur archaeologists) has contributed significantly to archaeological research and heritage practice in Denmark. Metal detecting has always been legal in Denmark, and official stakeholders have from...... the beginning of metal detector archaeology pursued a liberal model, focusing on cooperation and inclusion rather than confrontation and criminalization. Like no other surveying method, the metal detector has contributed to increasing enormously the amount of data and sites from metal-rich periods. Virtually...... 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. Metal Borohydrides synthesized from metal borides and metal hydrides

      DEFF Research Database (Denmark)

      Sommer, Sanna

      2014-01-01

      Metal Borohydrides Synthesized from Metal Borides and Metal Hydrides Alexander Fogha, Sanna Sommera, Kasper T. Møllera, T. R. Jensena aCenter for Materials Crystallography (CMC), Interdisciplinary Nanoscience Center (iNANO) and Chemistry Department, Aarhus University, Langelandsgade 140, DK-8000...... 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...... and Ca(BH4)2, respectively [3,4]. An attempt to synthesize alkali and alkaline earth metal borohydrides from various borides by ball milling under high hydrogen pressure is presented here. MgB2, AlB2 and CaB6 have been milled with MHx (M = Li, Na, Mg, Ca) at p(H2) = 110 bar for 24 hours. All samples were...

    8. Thin Metallic Films from Solvated Metal Atoms.

      Science.gov (United States)

      1987-07-14

      research has developed over the past two decades that deals with the generation of atoms of metals (by metal evaporation, and the interaction of these...Departamento de Quimica , Universidad de Concepcion, Cassilla 3-:, c oncepcion, Chile. -I{ - ~ *~.’JS*~M 4 .~4\\ 821 19 the gold particles were negatively...flocculation were observed, as shown in table a Generally about 0.1 g In was Suspended in 100-200 nl solvent. Several approacies to characterization of

    9. 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.

    10. 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.

    11. Efeitos adversos do sufentanil associado ao anestésico local pelas vias subaracnóidea e peridural em pacientes submetidas à analgesia de parto Efectos adversos del sufentanil asociado al anestésico local por las vías subaracnoidea y peridural en pacientes sometidas a la analgesia de parto Side effects of subarachnoid and epidural sufentanil associated with a local anesthetic in patients undergoing labor analgesia

      Directory of Open Access Journals (Sweden)

      Isabel C.F. Salem

      2007-04-01

      utilizadas, administrado por via subaracnóidea ou peridural, associado aos anestésicos locais, determinou similaridade na duração do trabalho de parto após analgesia e no Apgar dos recém-nascidos. A sedação foi o efeito adverso mais freqüente nas pacientes que receberam o opióide pela via peridural.JUSTIFICATIVA Y OBJETIVOS: La asociación del opioide con el anestésico local mejora la calidad de la analgesia de parto y reduce el riesgo de toxicidad sistémica por el anestésico local. Los opioides, sin embargo, pueden determinar efectos colaterales. El objetivo de esta investigación fue comparar los efectos adversos determinados por el sufentanil, administrado por vía subaracnoidea, asociado a la bupivacaína, con aquel determinado por el sufentanil por vía peridural, asociado a la ropivacaína, en las dosis utilizadas en el Servicio de Anestesia, en embarazadas sometidas a la analgesia de parto. MÉTODO: Participaron del estudio 60 pacientes, estado físico ASA I y II, con edad entre los 15 y los 42 años, con embarazo en tiempo y fetos saludables, sometidas a la analgesia de parto. Se distribuyeron aleatoriamente en de los grupos: G1 Doble bloqueo bupivacaína a 0,5% (2,5 mg y sufentanil (5 µg por vía subaracnoidea, G2 Peridural ropivacaína a 0,2% (20 mg y sufentanil (10 µg por vía peridural. Para dosis complementarias fue administrada ropivacaína a 0,2% (12 mg y para resolución del parto, ropivacaína a 1% (50 mg. Las pacientes se evaluaron después de la analgesia (M1 con relación a la hipotensión arterial, bradicardia materna, prurito, náusea, vómito, depresión respiratoria y sedación. En el postoperatorio (M2, en cuanto a la presencia de náusea, vómito, prurito, sedación, retención urinaria y dolor. Los recién nacidos se evaluaron por el índice de Apgar. Para análisis estadístico, se utilizaron la prueba t de Student, Mann-Whitney y Qui-cuadrado. RESULTADOS: Los grupos fueron similares con relación a la edad, al peso, a la altura, a

    12. 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.)

    13. 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.

    14. 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...

    15. 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

    16. Supported metal alloy catalysts

      Science.gov (United States)

      Barrera, Joseph; Smith, David C.

      2000-01-01

      A process of preparing a Group IV, V, or VI metal carbonitride including reacting a Group IV, V, or VI metal amide complex with ammonia to obtain an intermediate product; and, heating the intermediate product to temperatures and for times sufficient to form a Group IV, V, or VI metal carbonitride is provided together with the product of the process and a process of reforming an n-alkane by use of the product.

    17. 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

    18. 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.)

    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. 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)

    1. 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

    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. 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)

    4. Metal weight table

      International Nuclear Information System (INIS)

      1995-03-01

      This book is comprised of two parts about metallic material weight table. the first part deals with steel on weight table of section steel and bar steel, hexagonal steel, equal angle steel, unequal angle steel, channel steel, T steel, H steel, CT steel, light gauge steel, light rail, stainless steel weight calculation, carbon steel pipe for general rescue a circular nail, zinc galvanizing and wire lope. The second part is about nonferrous metal on weight calculation for nonferrous metal nonferrous metal plates, steel pipe, brass copper bar and aluminum.

    5. Metal-on-Metal Hip Resurfacing Arthroplasty

      Science.gov (United States)

      Sehatzadeh, S; Kaulback, K; Levin, L

      2012-01-01

      Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the

    6. Silicon metal-semiconductor-metal photodetector

      Science.gov (United States)

      Brueck, Steven R. J.; Myers, David R.; Sharma, Ashwani K.

      1995-01-01

      Silicon MSM photodiodes sensitive to radiation in the visible to near infrared spectral range are produced by altering the absorption characteristics of crystalline Si by ion implantation. The implantation produces a defected region below the surface of the silicon with the highest concentration of defects at its base which acts to reduce the contribution of charge carriers formed below the defected layer. The charge carriers generated by the radiation in the upper regions of the defected layer are very quickly collected between biased Schottky barrier electrodes which form a metal-semiconductor-metal structure for the photodiode.

    7. Hardness of metallic crystals

      Indian Academy of Sciences (India)

      Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China; Henan Key Laboratory of Advanced Non-ferrous Metals, Luoyang 471003, China; School of Materials Science and Engineering, Henan University of Science and Technology, ...

    8. Bioaccumulation of Heavy Metals

      African Journals Online (AJOL)

      komla

      between amounts of metals in the aquatic insects and the surrounding water medium,. Materials and methods indicating that most of the accumulated. Test animals metals were from the water medium. Tympanotonus fuscatus var. radula L. The significance of bioaccumulation. (Periwinkle) (Mollusca; Gastropoda, studies lies ...

    9. 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

    10. 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

    11. 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....

    12. Virus templated metallic nanoparticles

      Science.gov (United States)

      Aljabali, Alaa A. A.; Barclay, J. Elaine; Lomonossoff, George P.; Evans, David J.

      2010-12-01

      Plant viruses are considered as nanobuilding blocks that can be used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. used as synthons or templates for novel materials. Cowpea mosaic virus (CPMV) particles have been shown to template the fabrication of metallic nanoparticles by an electroless deposition metallization process. Palladium ions were electrostatically bound to the virus capsid and, when reduced, acted as nucleation sites for the subsequent metal deposition from solution. The method, although simple, produced highly monodisperse metallic nanoparticles with a diameter of ca. agarose gel electrophoresis results, energy dispersive X-ray spectra, ζ-potential measurements, dynamic light scattering data, nanoparticle tracking analysis and an atomic force microscopy image of Ni-CPMV. See DOI: 10.1039/c0nr00525h

    13. 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.

    14. Metal borohydrides and derivatives

      DEFF Research Database (Denmark)

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

      2017-01-01

      review new synthetic strategies along with structural, physical and chemical properties for metal borohydrides, revealing a number of new trends correlating composition, structure, bonding and thermal properties. These new trends provide general knowledge and may contribute to the design and discovery......A wide variety of metal borohydrides, MBH4, have been discovered and characterized during the past decade, revealing an extremely rich chemistry including fascinating structural flexibility and a wide range of compositions and physical properties. Metal borohydrides receive increasing interest...... 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...

    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. 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.

    17. Evaluation of the Quality of Life of Gynecological Cancer Patients Submitted to Antineoplastic Chemotherapy Evaluación de la calidad de vida de portadoras de cáncer ginecológico, sometidas a quimioterapia antineoplásica Avaliação da qualidade de vida de portadoras de câncer ginecológico, submetidas à quimioterapia antineoplásica

      Directory of Open Access Journals (Sweden)

      Lívia Loamí Ruyz Jorge

      2010-10-01

      Full Text Available This study aimed to evaluate the quality of life of female gynecological cancer patients submitted to antineoplastic chemotherapy Between August 2007 and April 2009, 50 patients who were undergoing chemotherapy at an outpatient chemotherapy unit in Uberaba - MG were interviewed, by applying the instrument of evaluation of Quality of Life of the World Health Organization, WHOQOL-BREF. The results showed that the domain most affected was the Physical and the more preserved, the Social, with the mean of the general quality of life above the means obtained in other studies. All domains correlated significantly with the general quality of life. It was evident then that the quality of life of these women is satisfactory, however it is suggested that the domains with lower scores be the targets of more accurate observations during multi-professional interventions in order to provide a better quality of life during the chemotherapy treatment.Este estudio tuvo como objetivo evaluar la calidad de vida de mujeres portadoras de cáncer ginecológico sometidas a quimioterapia antineoplásica. Fueron entrevistadas 50 pacientes en el período de agosto de 2007 a abril de 2009 que estaban en tratamiento quimioterapéutico en un ambulatorio de quimioterapia de Uberaba-MG, mediante la aplicación del instrumento de evaluación de Calidad de Vida de la Organización Mundial de la Salud-WHOQOL-bref. Los resultados apuntaron que el dominio más comprometido fue el físico y el más preservado, el social, siendo que la calidad de vida general obtuvo un promedio superior al obtenido en otros estudios. Todos los dominios se correlacionaron significativamente con la calidad de vida general. Se puede evidenciar, entonces, que la calidad de vida de esas mujeres fue satisfactoria; sin embargo se sugiere que los dominios con puntajes más bajos sean examinados con observaciones más exactas durante las intervenciones multiprofesionales, a fin de proporcionar una mejor

    18. Framework for Metals Risk Assessment

      Science.gov (United States)

      The Framework for Metals Risk Assessment is a science-based document that addresses the special attributes and behaviors of metals and metal compounds to be considered when assessing their human health and ecological risks.

    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. 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.

    1. 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.

    2. Nanoporous metal-carbon composite

      Energy Technology Data Exchange (ETDEWEB)

      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.

    3. Preparation of uniform nanoparticles of ultra-high purity metal oxides, mixed metal oxides, metals, and metal alloys

      Science.gov (United States)

      Woodfield, Brian F.; Liu, Shengfeng; Boerio-Goates, Juliana; Liu, Qingyuan; Smith, Stacey Janel

      2012-07-03

      In preferred embodiments, metal nanoparticles, mixed-metal (alloy) nanoparticles, metal oxide nanoparticles and mixed-metal oxide nanoparticles are provided. According to embodiments, the nanoparticles may possess narrow size distributions and high purities. In certain preferred embodiments, methods of preparing metal nanoparticles, mixed-metal nanoparticles, metal oxide nanoparticles and mixed-metal nanoparticles are provided. These methods may provide tight control of particle size, size distribution, and oxidation state. Other preferred embodiments relate to a precursor material that may be used to form nanoparticles. In addition, products prepared from such nanoparticles are disclosed.

    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. 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.

    7. 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.

    8. Triple Point Topological Metals

      Directory of Open Access Journals (Sweden)

      Ziming Zhu

      2016-07-01

      Full Text Available Topologically protected fermionic quasiparticles appear in metals, where band degeneracies occur at the Fermi level, dictated by the band structure topology. While in some metals these quasiparticles are direct analogues of elementary fermionic particles of the relativistic quantum field theory, other metals can have symmetries that give rise to quasiparticles, fundamentally different from those known in high-energy physics. Here, we report on a new type of topological quasiparticles—triple point fermions—realized in metals with symmorphic crystal structure, which host crossings of three bands in the vicinity of the Fermi level protected by point group symmetries. We find two topologically different types of triple point fermions, both distinct from any other topological quasiparticles reported to date. We provide examples of existing materials that host triple point fermions of both types and discuss a variety of physical phenomena associated with these quasiparticles, such as the occurrence of topological surface Fermi arcs, transport anomalies, and topological Lifshitz transitions.

    9. 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

    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. Quasicrystalline metallic adlayers

      Indian Academy of Sciences (India)

      ugc

      Quasicrystalline metallic adlayers. S. R. Barman. UGC-DAE Consortium for Scientific Research, Indore. 23rd Mid-year Meeting of the Indian Academy of Sciences,. July 13-14, 2012,. Indian Institute of Science, Bangalore.

    13. Atmospheric Heavy Metal Pollution

      Indian Academy of Sciences (India)

      Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 4. Atmospheric Heavy Metal Pollution - Development of Chronological Records and Geochemical Monitoring. Rohit Shrivastav. General Article Volume 6 Issue 4 April 2001 pp 62-68 ...

    14. Hydrogen in metals

      CSIR Research Space (South Africa)

      Carter, TJ

      2001-04-01

      Full Text Available of hydrogen in metals processing and treatment identified, and mechanisms for hydrogen entry into a ferritic surface are discussed. The differences between hydrogen attack of ferritic steels and copper alloys are contrasted, and an unusual case study...

    15. 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...

    16. Hardness of metallic crystals

      Indian Academy of Sciences (India)

      Administrator

      -known Hall–Petch relationship predicts that the strength or hardness of conventional metal alloys increases with decreasing grain sizes. However, the rela- tionship fails when the grain size is down to nanometers as many experimental results ...

    17. 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)

    18. Metal-Semiconductor Contacts

      Science.gov (United States)

      Pugh, D. I.

      Metal-semiconductor contacts display a range of electrical characteristics from strongly rectifying to ohmic, each having its own applications. The rectifying properties of metal points on metallic sulphides were used extensively as detectors in early radio experiments, while during the second world war the rectifying point contact diode became important as a frequency detector and low level microwave radar detector [1]. Since 1945 the development of metal semiconductor contacts has been stimulated by the intense activity in the field of semiconductor physics and has remained vital in the ohmic connection of semiconductor devices with the outside world. The developments in surface science and the increased use of Schottky barriers in microelectronics has lead to much research with the aim of obtaining a full understanding of the physics of barrier formation and of current transport across the metal-semiconductor interface. Large gain spin electronic devices are possible with appropriate designs by incorporating ferromagnetic layers with semiconductors such as silicon [2]. This inevitably leads to metal-semiconductor contacts, and the impact of such junctions on the device must be considered. In this section we aim to look simply at the physical models that can be used to understand the electrical properties that can arise from these contacts, and then briefly discuss how deviations of these models can occur in practical junctions.

    19. Metals in fungal virulence.

      Science.gov (United States)

      Gerwien, Franziska; Skrahina, Volha; Kasper, Lydia; Hube, Bernhard; Brunke, Sascha

      2018-01-01

      Metals are essential for life, and they play a central role in the struggle between infecting microbes and their hosts. In fact, an important aspect of microbial pathogenesis is the 'nutritional immunity', in which metals are actively restricted (or, in an extended definition of the term, locally enriched) by the host to hinder microbial growth and virulence. Consequently, fungi have evolved often complex regulatory networks, uptake and detoxification systems for essential metals such as iron, zinc, copper, nickel and manganese. These systems often differ fundamentally from their bacterial counterparts, but even within the fungal pathogens we can find common and unique solutions to maintain metal homeostasis. Thus, we here compare the common and species-specific mechanisms used for different metals among different fungal species-focusing on important human pathogens such as Candida albicans, Aspergillus fumigatus or Cryptococcus neoformans, but also looking at model fungi such as Saccharomyces cerevisiae or A. nidulans as well-studied examples for the underlying principles. These direct comparisons of our current knowledge reveal that we have a good understanding how model fungal pathogens take up iron or zinc, but that much is still to learn about other metals and specific adaptations of individual species-not the least to exploit this knowledge for new antifungal strategies. © FEMS 2017.

    20. Heavy Metal - Exploring a magnetised metallic asteroid

      Science.gov (United States)

      Wahlund, Jan-Erik; Andrews, David; Futaana, Yoshifumi; Masters, Adam; Thomas, Nicolas; De Sanctis, Maria Cristina; Herique, Alain; Retherford, Kurt; Tortora, Paolo; Trigo-Rodriguez, Joseph; Ivchenko, Nickolay; Simon, Sven

      2017-04-01

      We propose a spacecraft mission (Heavy Metal) 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, 2.7×10(19) kg make it one of the largest and densest of asteroids, 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. The M5 mission Heavy Metal will investigate if (16) Psyche is the exposed metallic core of a planetesimal, formed early enough to melt and differentiate. High-resolution mapping of the surface in optical, IR, UV and radar wavebands, along with the determination of the shape and gravity field will be used to address the formation and subsequent evolution of (16) Psyche, determining the origin of metallic asteroids. It is conceivable that a cataclysmic collision with a second body led to the ejection of all or part of the differentiated core of the parent body. Measurements at (16) Psyche therefore provide a possibility to directly examine an iron-rich planetary core, similar to that expected at the center of all the major planets including Earth. A short-lived dynamo producing a magnetic field early in the life of (16) Psyche could have led to a remnant field (of tens of micro Tesla) being preserved in the body today. (16) Psyche is embedded in the variable flow of the solar wind. Whereas planetary magnetospheres and induced magnetospheres are the result of intense dynamo fields and dense conductive ionospheres presenting obstacles to the solar wind, (16) Psyche may show an entirely new 'class' of interaction as a consequence of its lack of a significant atmosphere, the extremely high bulk electrical conductivity of the asteroid, and the possible presence of intense magnetic fields retained in iron-rich material. The small characteristic scale of (16) Psyche ( 200 km) firmly places any solar wind interaction in the "sub-MHD" scale, in which kinetic

    1. Electrochemical nitridation of metal surfaces

      Science.gov (United States)

      Wang, Heli; Turner, John A.

      2015-06-30

      Electrochemical nitridation of metals and the produced metals are disclosed. An exemplary method of electrochemical nitridation of metals comprises providing an electrochemical solution at low temperature. The method also comprises providing a three-electrode potentiostat system. The method also comprises stabilizing the three-electrode potentiostat system at open circuit potential. The method also comprises applying a cathodic potential to a metal.

    2. Toxic metals and autophagy.

      Science.gov (United States)

      Chatterjee, Sarmishtha; Sarkar, Shuvasree; Bhattacharya, Shelley

      2014-11-17

      The earth's resources are finite, and it can no longer be considered a source of inexhaustible bounty for the human population. However, this realization has not been able to contain the human desire for rapid industrialization. The collateral to overusing environmental resources is the high-level contamination of undesirable toxic metals, leading to bioaccumulation and cellular damage. Cytopathological features of biological systems represent a key variable in several diseases. A review of the literature revealed that autophagy (PCDII), a high-capacity process, may consist of selective elimination of vital organelles and/or proteins that intiate mechanisms of cytoprotection and homeostasis in different biological systems under normal physiological and stress conditions. However, the biological system does survive under various environmental stressors. Currently, there is no consensus that specifies a particular response as being a dependable biomarker of toxicology. Autophagy has been recorded as the initial response of a cell to a toxic metal in a concentration- and time-dependent manner. Various signaling pathways are triggered through cellular proteins and/or protein kinases that can lead to autophagy, apoptosis (or necroptosis), and necrosis. Although the role of autophagy in tumorigenesis is associated with promoting tumor cell survival and/or acting as a tumor suppressive mechanism, PCDII in metal-induced toxicity has not been extensively studied. The aim of this review is to analyze the comparative cytotoxicity of metals/metalloids and nanoparticles (As, Cd, Cr, Hg, Fe, and metal-NP) in cells enduring autophagy. It is noted that metals/metalloids and nanoparticles prefer ATG8/LC3 as a potent inducer of autophagy in several cell lines or animal cells. MAP kinases, death protein kinases, PI3K, AKT, mTOR, and AMP kinase have been found to be the major components of autophagy induction or inhibition in the context of cellular responses to metals/metalloids and

    3. 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.

    4. 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.

    5. Effects of metal-inlay thickness in polyethylene cups with metal-on-metal bearings.

      NARCIS (Netherlands)

      Verdonschot, N.J.J.; Vena, P.; Stolk, J.; Huiskes, R.

      2002-01-01

      A way to prevent polyethylene wear in total hip replacements is to use metal-on-metal bearings. The cup design of these bearings may be a metal inlay in a polyethylene cup. However, these metal inlays are relatively thin and may deform on loading. The purpose of the current study was to determine

    6. Self-reported neurological clinical manifestations of metal toxicity in metal-on-metal hip arthroplasty

      NARCIS (Netherlands)

      van Lingen, Christiaan P.; Ettema, Harmen B.; Van Der Straeten, Catherine; Kollen, Bouwdewijn J.; Verheyen, Cees C. P. M.

      2014-01-01

      Adverse reactions to metal particle debris have been increasingly reported as a complication following large head metal-on-metal (MoM) hip arthroplasty. Elevated metal ion levels are a cause for concern. The aim of this study is to evaluate whether exposure to cobalt is associated with patient

    7. Dissimilar metals joint evaluation

      Science.gov (United States)

      Wakefield, M. E.; Apodaca, L. E.

      1974-01-01

      Dissimilar metals tubular joints between 2219-T851 aluminum alloy and 304L stainless steel were fabricated and tested to evaluate bonding processes. Joints were fabricated by four processes: (1) inertia (friction) weldings, where the metals are spun and forced together to create the weld; (2) explosive welding, where the metals are impacted together at high velocity; (3) co-extrusion, where the metals are extruded in contact at high temperature to promote diffusion; and (4) swaging, where residual stresses in the metals after a stretching operation maintain forced contact in mutual shear areas. Fifteen joints of each type were prepared and evaluated in a 6.35 cm (2.50 in.) O.D. size, with 0.32 cm (0.13 in.) wall thickness, and 7.6 cm (3.0 in) total length. The joints were tested to evaluate their ability to withstand pressure cycle, thermal cycle, galvanic corrosion and burst tests. Leakage tests and other non-destructive test techniques were used to evaluate the behavior of the joints, and the microstructure of the bond areas was analyzed.

    8. 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.

    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. 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...

    11. Ultralight metal foams.

      Science.gov (United States)

      Jiang, Bin; He, Chunnian; Zhao, Naiqin; Nash, Philip; Shi, Chunsheng; Wang, Zejun

      2015-09-08

      Ultralight (battery electrodes; catalyst supports; and acoustic, vibration, or shock energy damping. However, most of these ultralight materials, especially ultralight metal foams, are fabricated using either expensive materials or complicated procedures, which greatly limit their large-scale production and practical applications. Here we report a simple and versatile method to obtain ultralight monolithic metal foams. These materials are fabricated with a low-cost polymeric template and the method is based on the traditional silver mirror reaction and electroless plating. We have produced ultralight monolithic metal foams, such as silver, nickel, cobalt, and copper via this method. The resultant ultralight monolithic metal foams have remarkably low densities down to 7.4 mg/cm3 or 99.9% porosity. The metal foams have a long flat stress-train curve in compression tests and the densification strain εD of the Ni/Ag foam with a porosity of 99.8% can reach 82%. The plateau stress σpl was measured and found to be in agreement with the value predicted by the cellular solids theory.

    12. LEVELING METAL COATINGS

      Science.gov (United States)

      Gage, H.A.

      1959-02-10

      A method is described for applying metallic coatings to a cylinder of uranium. An aluminum-silicon coat is applied by a process consisting of first cleaning the article by immersion for 5 minutes in 50% nitric acid at 65 C. The article then is dipped through a flux, prepared by adding 10% sodium fluoride to 90% of a flux comprising 53% potassium chloride, 42% lithium chloride, and 5% sodium chloride at 560 for 2 minutes and then directly into a molten metal bath comprising 99% aluminun and 12% silicon at 620 C for 3 minutes. While the coating is yet molten the article is transferred to a pair of steel rollers and rolled until the coating solidifies. By varying the composition of the flux other metals such as zinc, lead or the like may be coated on uranium in a similar manner.

    13. 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

    14. 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

    15. Noble metal ionic catalysts.

      Science.gov (United States)

      Hegde, M S; Madras, Giridhar; Patil, K C

      2009-06-16

      Because of growing environmental concerns and increasingly stringent regulations governing auto emissions, new more efficient exhaust catalysts are needed to reduce the amount of pollutants released from internal combustion engines. To accomplish this goal, the major pollutants in exhaust-CO, NO(x), and unburned hydrocarbons-need to be fully converted to CO(2), N(2), and H(2)O. Most exhaust catalysts contain nanocrystalline noble metals (Pt, Pd, Rh) dispersed on oxide supports such as Al(2)O(3) or SiO(2) promoted by CeO(2). However, in conventional catalysts, only the surface atoms of the noble metal particles serve as adsorption sites, and even in 4-6 nm metal particles, only 1/4 to 1/5 of the total noble metal atoms are utilized for catalytic conversion. The complete dispersion of noble metals can be achieved only as ions within an oxide support. In this Account, we describe a novel solution to this dispersion problem: a new solution combustion method for synthesizing dispersed noble metal ionic catalysts. We have synthesized nanocrystalline, single-phase Ce(1-x)M(x)O(2-delta) and Ce(1-x-y)Ti(y)M(x)O(2-delta) (M = Pt, Pd, Rh; x = 0.01-0.02, delta approximately x, y = 0.15-0.25) oxides in fluorite structure. In these oxide catalysts, Pt(2+), Pd(2+), or Rh(3+) ions are substituted only to the extent of 1-2% of Ce(4+) ion. Lower-valent noble metal ion substitution in CeO(2) creates oxygen vacancies. Reducing molecules (CO, H(2), NH(3)) are adsorbed onto electron-deficient noble metal ions, while oxidizing (O(2), NO) molecules are absorbed onto electron-rich oxide ion vacancy sites. The rates of CO and hydrocarbon oxidation and NO(x) reduction (with >80% N(2) selectivity) are 15-30 times higher in the presence of these ionic catalysts than when the same amount of noble metal loaded on an oxide support is used. Catalysts with palladium ion dispersed in CeO(2) or Ce(1-x)Ti(x)O(2) were far superior to Pt or Rh ionic catalysts. Therefore, we have demonstrated that the

    16. Heavy Metal Pumps in Plants

      Energy Technology Data Exchange (ETDEWEB)

      Harper, J.F.

      2000-10-01

      The long term goal of the funded research is to understand how heavy metals are taken up from the soil and translocated throughout the plant. The potential application of this research is to create plants with better heavy metal uptake systems and thereby improve the ability of these plants to help clean up toxic metals from soils. A rate limiting step is using plant for bioremediation is the normally poor capacity of plants to concentrate toxic metals. Our interest in metal ion transport systems includes those for essential mineral nutrients such as molybdenum, copper, iron, manganese, as well as toxic metals such as cerium, mercury, cesium, cadmium, arsenic and selenium. Understanding the pathways by which toxic metals accumulate in plants will enable the engineering of plants to exclude toxic metals and create healthier food sources, or to extract toxic metals from the soil as a strategy to clean up polluted lands and water.

    17. 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

    18. 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)

    19. 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.

    20. 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)

    1. 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

    2. 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

    3. Metallic coating of microspheres

      Energy Technology Data Exchange (ETDEWEB)

      Meyer, S.F.

      1980-08-15

      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.

    4. 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)

    5. 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.)

    6. FFTF metal fuel pin fabrication

      International Nuclear Information System (INIS)

      Dittmer, J.O.; Benecke, M.W.; Feigenbutz, L.V.

      1989-01-01

      A major new initiative to develop, irradiate, and qualify a binary uranium/zirconium metal-fuel system in the Fast Flux Test Facility (FFTF) has been implemented by the Westinghouse Hanford Company for the US Department of Energy. Metal-fuel test assemblies have been designed and fabricated, and are now being irradiated in FFTF to provide the data needed to support the potential use of binary metal fuels in FFTF and other liquid-metal reactors. These development efforts support licensing activities for metal-fuel use in near-term advanced liquid-metal reactors

    7. 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

    8. Metals in Metal Salts: A Copper Mirror Demonstration

      Science.gov (United States)

      Pike, Robert D.

      2010-01-01

      A simple lecture demonstration is described to show the latent presence of metal atoms in a metal salt. Copper(II) formate tetrahydrate is heated in a round-bottom flask forming a high-quality copper mirror.

    9. Metal-on-metal bearings a clinical practicum

      CERN Document Server

      Jones, Lynne C; Greenwald, A Seth

      2014-01-01

      This book addresses the background and significance of factors potentially influencing clinical and biological outcomes of metal-on-metal hip implants. Includes discussion of reported complications including pseudotumors and other lymphocytic-based responses.

    10. 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

    11. Interações no rádio musical expandido: Um aporte etnográfico

      Directory of Open Access Journals (Sweden)

      Marcelo Kischinhevsky

      2014-12-01

      Full Text Available Interactions on expanded musical radio: An ethnographic contribution – This paper investigates interactional practices on expanded musical radio (from Hertzian airwaves to the Internet, taking as a case study the podcast Muqueca de Siri, which is dedicated to samba. Throughout the text, we discuss the pertinence of the ethnographic approach in researches about the reception/consumption of music radio in a new media environment with continually multiplying possibilities of sound production and circulation, shaping communities of listeners who switch between online and offline worlds.

    12. ANÁLISE DAS PROPRIEDADES FÍSICAS E MECÂNICAS DO CONCRETO PRODUZIDO COM POLIESTIRENO EXPANDIDO (EPS

      Directory of Open Access Journals (Sweden)

      Bruno Peruqui Guidio

      2014-12-01

      Full Text Available Currently, concrete is the most utilized material in construction and their weight itself compared to applied loads is high. Therefore reducing your weight through lightweight aggregates, the target of several studies aiming at the production of lightweight concrete, known by the low specific weight and high capacity for thermal and acoustic insulation is becoming. The mechanical behavior of different traits in concrete was compared with a gradual replacement of natural coarse aggregates for Expanded Polystyrene (EPS, evaluating the density and mechanical resistance to compression. The reference concrete had resistance to compression of 27MPa at 28 days of age, since the concrete produced with EPS showed lower results, and with 10% substitution showed resistance 20,71MPa to 28 days. The concrete EPS is lighter checked by reducing the specific weight, which may be favorable in some situations.

    13. 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.

    14. Degradación de disolventes orgánicos de uso industrial en un reactor anaerobio de lecho expandido

      OpenAIRE

      Lafita Lopez, Carlos

      2016-01-01

      La contaminación atmosférica constituye actualmente una seria amenaza para el medio ambiente y la salud. En este sentido, las emisiones de compuestos orgánicos volátiles (COV) pueden contribuir de forma importante a la contaminación atmosférica. Una gran parte de estos compuestos se emiten en procesos productivos en los que se utilizan disolventes, de forma que las industrias que realizan estas actividades han de reducir su emisión hasta los límites establecidos en la legislación mediante cam...

    15. El campo expandido de la crítica de arte: análisis discursivo de un debate

      Directory of Open Access Journals (Sweden)

      Elkin Rubiano

      2014-01-01

      Full Text Available El propósito de este artículo es entender qué sucedió con el debate que se dio entre el portal de crítica Esferapublica.org y los medios informativos escritos entre el 26 de agosto y el 23 de septiembre de 2009, en torno al performance de Tania Bruguera: Sin título (Bogotá, 2009. En él, la artista cubana puso a circular algunas bandejas de cocaína entre el público asistente, mientras tres actores del conflicto armado colombiano hablaban sobre la construcción política del héroe. A partir de un análisis discursivo se establece qué tipo de crítica se pone en práctica en un medio alternativo.

    16. Metal separation from multi metallic solutions by grape stalks

      OpenAIRE

      Stevens, Bas

      2016-01-01

      With the rapid development of various industries such as mine and metallurgy, wastewaters containing metals are directly or indirectly discharged into the environment. One of the most dangerous effluents discharged are Acid Mine Drainage (AMD), the outflows of acidic waters from metal mines. This water needs to be treated so it can be reused and the metal ions in this polluted water can be recuperated. The metals that occur in the polluted water are difficult to eliminate. To e...

    17. 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.

    18. Atmospheric Heavy Metal Pollution

      Indian Academy of Sciences (India)

      within and below cloud scavenging, whereby the wet aerosol particles are collected by falling raindrops. In occult deposition, wetted particles (fog and mist) are deposited by impaction or turbulent transfer [3]. A high proportion of atmospheric heavy metals entering aquatic systems is in small particulate « IJlm) or soluble ...

    19. 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 ...

    20. Wings of Stretched Metal

      Science.gov (United States)

      Nelken, Miranda

      2010-01-01

      This article presents a lesson that allows students to make bird ornaments using a metal tooling as it can be textured, cut, and colored. In this lesson, students choose a bird and sketch it on a piece of paper. Once the sketches are complete, students copy their pictures on a second piece of paper by taping the sketch over a sheet of blank paper…

    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. 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...

    3. 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.

    4. Metal Organic Framework

      Indian Academy of Sciences (India)

      IAS Admin

      X-ray crystallography is the most comprehensive character- ization tool to gain a molecular level understanding of a range of crystalline materials. One of the recent areas in which research with the aid of crystallography has exploded, is the metal organic frameworks (MOFs). These are porous crystal- line solids with ...

    5. 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.

    6. Hardness of metallic crystals

      Indian Academy of Sciences (India)

      This paper presents a new formula for calculating the hardness of metallic crystals, resulted from the research on the critical grain size with stable dislocations. The formula is = 6 /[(1 – )], where is the hardness, the coefficient, the shear modulus, the Poisson's ratio, a function of the radius of an atom () ...

    7. 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...

    8. 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...

    9. Monolithic metal oxide transistors.

      Science.gov (United States)

      Choi, Yongsuk; Park, Won-Yeong; Kang, Moon Sung; Yi, Gi-Ra; Lee, Jun-Young; Kim, Yong-Hoon; Cho, Jeong Ho

      2015-04-28

      We devised a simple transparent metal oxide thin film transistor architecture composed of only two component materials, an amorphous metal oxide and ion gel gate dielectric, which could be entirely assembled using room-temperature processes on a plastic substrate. The geometry cleverly takes advantage of the unique characteristics of the two components. An oxide layer is metallized upon exposure to plasma, leading to the formation of a monolithic source-channel-drain oxide layer, and the ion gel gate dielectric is used to gate the transistor channel effectively at low voltages through a coplanar gate. We confirmed that the method is generally applicable to a variety of sol-gel-processed amorphous metal oxides, including indium oxide, indium zinc oxide, and indium gallium zinc oxide. An inverter NOT logic device was assembled using the resulting devices as a proof of concept demonstration of the applicability of the devices to logic circuits. The favorable characteristics of these devices, including (i) the simplicity of the device structure with only two components, (ii) the benign fabrication processes at room temperature, (iii) the low-voltage operation under 2 V, and (iv) the excellent and stable electrical performances, together support the application of these devices to low-cost portable gadgets, i.e., cheap electronics.

    10. Pile on the metal

      Science.gov (United States)

      Lee, Dung-Hai

      2008-09-01

      Discovering superconductivity above room temperature is a dream for modern science and technology. Now, theorists propose that for certain types of superconductors, contact with a metal layer could greatly increase the transition temperatures of these materials—in some cases by as much as an order of magnitude.

    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. 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.

    13. 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 ...

    14. 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.

    15. 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 ...

    16. 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 ...

    17. 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...

    18. 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

    19. 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....... These insights provide an answer to the question why blackletter scripts have become part of the visual repertoire of metal music and why so many famous metal band logotypes are based on blackletter....

    20. Birch's Law for fluid metals

      International Nuclear Information System (INIS)

      Shaner, J.W.; Hixson, R.S.; Winkler, M.A.; Boness, D.A.; Brown, J.M.

      1987-01-01

      By comparing acoustic velocities in fluid metals over a very wide range of densities we have established Birch's Law as an approximate representation over the entire liquid range. For a given liquid metal the acoustic velocity is close to linear in density, with a slope determined by the atomic weight. The measurements include isobaric expansion to less than half normal density, ultrasonics on molten metals at 1 atmosphere, and shock melted metals to greater than twice normal density

    1. 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.

    2. 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.

    3. Metal allergy and second-generation metal-on-metal arthroplasties.

      Science.gov (United States)

      Cousen, Philippa J; Gawkrodger, David J

      2012-02-01

      There are concerns about the induction of metal allergy with second-generation metal-on-metal prostheses, and the role that this may play in the development of complications such as 'pseudotumours' or failure of the implant. In this review, we attempt to set out the current knowledge on this subject. From a review of the literature, it is apparent that the first-generation metal-on-metal replacement hips did cause metal sensitization, and that joint failure was associated with this, although it is still not clear which one led to the other. Highly engineered second-generation metal-on-metal arthroplasties used in joint resurfacings are now increasingly employed. Several studies have recently shown an association between metal sensitization and peri-implant hypersensitivity reactions and implant loosening and failure, although the overall risk appears to be low. The pragmatic approach adopted by most contact dermatologists for patients known to be allergic to nickel, cobalt or chromium and who require joint replacement is to recommend prostheses made of titanium-based alloys. Patch testing continues to be a useful tool as laboratory investigations for metal hypersensitivity continue to emerge. The development of guidelines on the management of patients receiving metal-on-metal arthroplasties suspected of being metal-allergic is desirable. © 2011 John Wiley & Sons A/S.

    4. Neurotoxicity of Metal Mixtures.

      Science.gov (United States)

      Andrade, V M; Aschner, M; Marreilha Dos Santos, A P

      2017-01-01

      Metals are the oldest toxins known to humans. Metals differ from other toxic substances in that they are neither created nor destroyed by humans (Casarett and Doull's, Toxicology: the basic science of poisons, 8th edn. McGraw-Hill, London, 2013). Metals are of great importance in our daily life and their frequent use makes their omnipresence and a constant source of human exposure. Metals such as arsenic [As], lead [Pb], mercury [Hg], aluminum [Al] and cadmium [Cd] do not have any specific role in an organism and can be toxic even at low levels. The Substance Priority List of Agency for Toxic Substances and Disease Registry (ATSDR) ranked substances based on a combination of their frequency, toxicity, and potential for human exposure. In this list, As, Pb, Hg, and Cd occupy the first, second, third, and seventh positions, respectively (ATSDR, Priority list of hazardous substances. U.S. Department of Health and Human Services, Public Health Service, Atlanta, 2016). Besides existing individually, these metals are also (or mainly) found as mixtures in various parts of the ecosystem (Cobbina SJ, Chen Y, Zhou Z, Wub X, Feng W, Wang W, Mao G, Xu H, Zhang Z, Wua X, Yang L, Chemosphere 132:79-86, 2015). Interactions among components of a mixture may change toxicokinetics and toxicodynamics (Spurgeon DJ, Jones OAH, Dorne J-L, Svendsen C, Swain S, Stürzenbaum SR, Sci Total Environ 408:3725-3734, 2010) and may result in greater (synergistic) toxicity (Lister LJ, Svendsen C, Wright J, Hooper HL, Spurgeon DJ, Environ Int 37:663-670, 2011). This is particularly worrisome when the components of the mixture individually attack the same organs. On the other hand, metals such as manganese [Mn], iron [Fe], copper [Cu], and zinc [Zn] are essential metals, and their presence in the body below or above homeostatic levels can also lead to disease states (Annangi B, Bonassi S, Marcos R, Hernández A, Mutat Res 770(Pt A):140-161, 2016). Pb, As, Cd, and Hg can induce Fe, Cu, and Zn

    5. Fabrication of metallic glass structures

      Science.gov (United States)

      Cline, C.F.

      1983-10-20

      Amorphous metal powders or ribbons are fabricated into solid shapes of appreciable thickness by the application of compaction energy. The temperature regime wherein the amorphous metal deforms by viscous flow is measured. The metal powders or ribbons are compacted within the temperature regime.

    6. Bygningsmaterialer - Metallære

      DEFF Research Database (Denmark)

      Nielsen, Anders

      Textbook on basic metallurgy for civil engineering students on their first courses. The basic properties and corrosion properties of metals are treated in common. Steel and the heat treatments of steel, light metals and other metals used in the civil engineering are described....

    7. 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…

    8. 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.

    9. 21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

      Science.gov (United States)

      2010-04-01

      ... constrained cemented prosthesis. 888.3640 Section 888.3640 Food and Drugs FOOD AND DRUG ADMINISTRATION... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

    10. 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.

    11. Electrodynamics of Metallic Superconductors

      Directory of Open Access Journals (Sweden)

      M. Dressel

      2013-01-01

      Full Text Available The theoretical and experimental aspects of the microwave, terahertz, and infrared properties of superconductors are discussed. Electrodynamics can provide information about the superconducting condensate as well as about the quasiparticles. The aim is to understand the frequency dependence of the complex conductivity, the change with temperature and time, and its dependence on material parameters. We confine ourselves to conventional metallic superconductors, in particular, Nb and related nitrides and review the seminal papers but also highlight latest developments and recent experimental achievements. The possibility to produce well-defined thin films of metallic superconductors that can be tuned in their properties allows the exploration of fundamental issues, such as the superconductor-insulator transition; furthermore it provides the basis for the development of novel and advanced applications, for instance, superconducting single-photon detectors.

    12. 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.

    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. 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)

    16. 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

    17. 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.

    18. 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...

    19. 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

    20. Electron energies in metals

      Energy Technology Data Exchange (ETDEWEB)

      Mahan, G.D. (Oak Ridge National Lab., TN (United States) Tennessee Univ., Knoxville, TN (United States). Dept. of Physics and Astronomy)

      1991-07-10

      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{sub e}. This should be compared to the band mass found from optical conductivity m*/m{sub e} = 1.01 {plus minus} 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.

    1. 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

    2. 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...... the supersaturated alloy, into a diverse carbide network. Finally, the foils turn into metal dust accompanied by a thinning and disappearance of the foils. Investigations of TEM samples, prepared by means of FIB, on the carbide network revealed a lamellar structure with carbides and austenite. Finally, the mutual...... influence of oxygen and carbon on the metal dusting corrosion is explored. The results indicate that exposure to metal dusting conditions have a detrimental effect on the resistance against oxidation and, conversely, that exposure to oxidation has a detrimental effect on the resistance towards metal dusting...

    3. Reduction of Metal Oxide to Metal using Ionic Liquids

      Energy Technology Data Exchange (ETDEWEB)

      Dr. Ramana Reddy

      2012-04-12

      A novel pathway for the high efficiency production of metal from metal oxide means of electrolysis in ionic liquids at low temperature was investigated. The main emphasis was to eliminate the use of carbon and high temperature application in the reduction of metal oxides to metals. The emphasis of this research was to produce metals such as Zn, and Pb that are normally produced by the application of very high temperatures. The reduction of zinc oxide to zinc and lead oxide to lead were investigated. This study involved three steps in accomplishing the final goal of reduction of metal oxide to metal using ionic liquids: 1) Dissolution of metal oxide in an ionic liquid, 2) Determination of reduction potential using cyclic voltammetry (CV) and 3) Reduction of the dissolved metal oxide. Ionic liquids provide additional advantage by offering a wide potential range for the deposition. In each and every step of the process, more than one process variable has been examined. Experimental results for electrochemical extraction of Zn from ZnO and Pb from PbO using eutectic mixtures of Urea ((NH2)2CO) and Choline chloride (HOC2H4N(CH3)3+Cl-) or (ChCl) in a molar ratio 2:1, varying voltage and temperatures were carried out. Fourier Transform Infra-Red (FTIR) spectroscopy studies of ionic liquids with and without metal oxide additions were conducted. FTIR and induction coupled plasma spectroscopy (ICPS) was used in the characterization of the metal oxide dissolved ionic liquid. Electrochemical experiments were conducted using EG&G potentiostat/galvanostat with three electrode cell systems. Cyclic voltammetry was used in the determination of reduction potentials for the deposition of metals. Chronoamperometric experiments were carried out in the potential range of -0.6V to -1.9V for lead and -1.4V to -1.9V for zinc. The deposits were characterized using XRD and SEM-EDS for phase, morphological and elemental analysis. The results showed that pure metal was deposited on the cathode

    4. Corrosion protective coating for metallic materials

      Science.gov (United States)

      Buchheit, R.G.; Martinez, M.A.

      1998-05-26

      Corrosion protective coatings for metallic materials, particularly aluminum and aluminum alloys, produced with simple, low-cost equipment and materials other than toxic metals or metal salts, or metal cyanides is disclosed. The metallic material is cleaned, degreased, and deoxidized, the surface is converted to a substantially alkaline condition, and the surface is chemically sealed with inorganic metal compounds. 1 fig.

    5. 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

    6. Study of concentrated metal-ammonia solutions: magnetic properties and non metal-metal transition

      International Nuclear Information System (INIS)

      Lelieur, Jean-Pierre

      1972-01-01

      The magnetic susceptibility of alkali metal-liquid ammonia solutions has been measured in the concentration range where the solutions show a progressive passage toward the metallic state. The Knight shift of the metal nuclei and the nitrogen nucleus have been determined as a function of concentration and temperature, in Na-NH 3 and Cs-NH 3 solutions. A phenomenological analysis of the transport properties of metal-ammonia solutions is also presented. This analysis permits the presentation of a model for the mechanism of the transition to the metallic state. (author) [fr

    7. 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.)

    8. Desempeño de semillas de crambe sometidas a tratamientos pre-germinativos

      OpenAIRE

      Rebeca Rocha Cardoso; Danúbia Aparecida Costa Nobre; Andréia Márcia Santos de Souza David; Hugo Tiago Ribeiro Amaro; Renato Antônio Borghetti; Márcia Regina Costa

      2014-01-01

      Encouraging the production and use of biodiesel, seeds of crambe today constitute one of the best options for the supply of raw material, is also an excellent alternative for autumn-winter crop rotation order. The aim of this study was to evaluate the efficiency of combined pre-germination treatments on the seed behavior of crambe. From a seed sample of FMS Brilhante cultivar, an experimental design completely randomized with a 2 x 5 factorial arrangement was performed. It was formed from com...

    9. 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.

    10. Comportamiento de cimentaciones superficiales sobre suelos granulares sometidas a solicitaciones dinámicas.

      OpenAIRE

      Estaire Gepp, José

      2011-01-01

      Se analiza el comportamiento dinámico de cimentaciones superficiales sobre suelos granulares mediante ensayos en modelo físico a escala reducida sobre mesa vibratoria. Estos ensayos se interpretan mediante un modelo de cálculo que incorpora una ecuación constitutiva enmarcada en la Teoría Generalizada de Plasticidad.

    11. Desempeño de semillas de crambe sometidas a tratamientos pre-germinativos

      Directory of Open Access Journals (Sweden)

      Rebeca Rocha Cardoso

      2014-05-01

      Full Text Available El objetivo del trabajo fue evaluar la eficiencia de los tratamientos pre-germinativos en el desempeño de las semillas de crambe (Crambe abyssinica Hochst.. El diseño experimental fue completamente al azar, con arreglo factorial 2 x 5, los tratamientos están constituidos por la combinación de dos lotes de semillas y cinco tratamientos pre-germinativos, con cuatro repeticiones de 50 semillas. Los lotes fueron formados por dos condiciones físicas: con y sin pericarpio. Los tratamientos empleados fueron: control (sin tratamiento; semillas pre-embebidas en solución de ácido giberélico a 4%, por 24 horas en diferentes concentraciones (400, 500 y 600 mg.L-1, y semillas pre-embebidas en agua destilada por 24 h como control (0,0. Se determinó el contenido de agua, porcentaje de germinación, primer contaje de germinación, emergencia de plántulas e índice de velocidad de emergencia. La remoción del pericarpio en semillas de crambe acelera la velocidad de germinación, pero, disminuye su porcentaje final. La pre-imbibición en ácido giberélico (400, 500 e 600 mg.L-1 por 24 horas proporcionó incrementos en la germinación y en el vigor de las semillas de crambe con pericarpio.

    12. 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.

    13. 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

    14. Enhanced Structural Support of Metal Sites as Nodes in Metal-Organic Frameworks Compared to Metal Complexes

      OpenAIRE

      Das, Sanjit

      2013-01-01

      Metal-organic frameworks are a new class of crystalline, porous solid-state materials with metal ions periodically linked by organic linkers. This gives rise to one-, two- or three-dimensional structures. Here, we compare the stability of similar metal sites toward external ligand (solvent) induced disruption of the coordination environment in metal complexes and in metal-organic frameworks. Our experimental results show that a metal site as node of a metal-organic framework retains much high...

    15. 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...

    16. 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.

    17. 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.

    18. 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

    19. 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

    20. Oxidation by metal salts

      International Nuclear Information System (INIS)

      Makhon'kov, D.I.; Cheprakov, A.V.; Rodkin, M.A.; Mil'chenko, A.Yu.; Beletskaya, I.P.

      1986-01-01

      Oxidation of toluene and para-substituted toluenes containing electron acceptor groups: p-toluic acid, p-methyltoluylate and p-nitrotoluene by ammonium cerium (4) nitrate and ammonium cerium (4) sulfate in aqueous solutions of trifluoroacetic acid in the presence of chlorides and bromides of alkali metals is studied. The rate and selectivity of oxidative halogenation in side chain and/or aromatic ring under the conditions studied depend both on the nature of substrate and halogenide-ion and on the reaction conditions and ligand surrounding of cerium (4) atom

    1. 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.

    2. 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.

    3. Metals removal from spent salts

      Science.gov (United States)

      Hsu, Peter C.; Von Holtz, Erica H.; Hipple, David L.; Summers, Leslie J.; Brummond, William A.; Adamson, Martyn G.

      2002-01-01

      A method and apparatus for removing metal contaminants from the spent salt of a molten salt oxidation (MSO) reactor is described. Spent salt is removed from the reactor and analyzed to determine the contaminants present and the carbonate concentration. The salt is dissolved in water, and one or more reagents may be added to precipitate the metal oxide and/or the metal as either metal oxide, metal hydroxide, or as a salt. The precipitated materials are filtered, dried and packaged for disposal as waste or can be immobilized as ceramic pellets. More than about 90% of the metals and mineral residues (ashes) present are removed by filtration. After filtration, salt solutions having a carbonate concentration >20% can be spray-dried and returned to the reactor for re-use. Salt solutions containing a carbonate concentration ion exchange column, which yields salt solutions that contain less than 1.0 ppm of contaminants.

    4. Epidemiological Approaches to Metal Toxicology

      DEFF Research Database (Denmark)

      Grandjean, Philippe; Budtz-Jørgensen, Esben

      2014-01-01

      Epidemiological methods are crucial to extract as much valid information as possible from human metal exposures. Thus, modern epidemiological approaches have elucidated human health effects that were not apparent in the past. At the same time, metal toxicology has served as a useful arena...... 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...... to their propensity to cause chronic or delayed toxicity, epidemiological studies of metal toxicity have focused on a wide variety of organ systems, subtle effects as well as mortality, and differences in susceptibility. Toxic metals often serve as paradigms of environmental and occupational toxicity...

    5. A red metallic oxide photocatalyst

      Science.gov (United States)

      Xu, Xiaoxiang; Randorn, Chamnan; Efstathiou, Paraskevi; Irvine, John T. S.

      2012-07-01

      Light absorption across the bandgap in semiconductors is exploited in many important applications such as photovoltaics, light emitting diodes and photocatalytic conversion. Metals differ from semiconductors in that there is no energy gap separating occupied and unoccupied levels; however, it is still possible to excite electrons between bands. This is evidenced by materials with metallic properties that are also strongly coloured. An important question is whether such coloured metals could be used in light harvesting or similar applications. The high conductivity of a metal would preclude sufficient electric field being available to separate photocarriers; however, the high carrier mobility in a metal might also facilitate kinetic charge separation. Here we clearly demonstrate for the first time the use of a red metallic oxide, Sr1-xNbO3 as an effective photocatalyst. The material has been used under visible light to photocatalyse the oxidation of methylene blue and both the oxidation and reduction of water assisted by appropriate sacrificial elements.

    6. Supported molten-metal catalysts

      Science.gov (United States)

      Datta, Ravindra; Singh, Ajeet; Halasz, Istvan; Serban, Manuela

      2001-01-01

      An entirely new class of catalysts called supported molten-metal catalysts, SMMC, which can replace some of the existing precious metal catalysts used in the production of fuels, commodity chemicals, and fine chemicals, as well as in combating pollution. SMMC are based on supporting ultra-thin films or micro-droplets of the relatively low-melting (metals and semimetals from groups 1, 12, 13, 14, 15 and 16, of the periodic table, or their alloys and intermetallic compounds, on porous refractory supports, much like supported microcrystallites of the traditional solid metal catalysts. It thus provides orders of magnitude higher surface area than is obtainable in conventional reactors containing molten metals in pool form and also avoids corrosion. These have so far been the chief stumbling blocks in the application of molten metal catalysts.

    7. 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.

    8. Metal-metal interactions among dietary toxic and essential trace metals in the rat

      Energy Technology Data Exchange (ETDEWEB)

      Elsenhans, B.; Schmolke, G.; Kolb, K.; Stokes, J.; Forth, W.

      1987-12-01

      Exposure to toxic and essential metals is thought to be reflected by corresponding metal concentrations in tissues. However, toxic and essential metals may influence each other in regard to their retention in the body. Therefore, a basic diet containing four toxic metals (As 7, Cd 9, Ni 13, and Pb 20 ppm) and adequate amounts of essential metals was fed to rats for 2 weeks. Test groups received the basic diet with increasing concentrations of one of the toxic metals (up to 90 ppm As, 180 ppm Cd, 365 ppm Ni, and 394 ppm Pb). As, Cd, Ni, Pb, Cu, Fe, Mn, and Zn were determined by atomic emission spectroscopy in liver, kidney, intestine, brain, muscle, bone, skin, hair, and blood. A linear relationship between diet and tissue concentration is observed for As and Ni in the kidney, for Cd in the liver, and for Pb in the bone. In other tissues saturation was observed. While Cd-Fe interactions were common to most of the tissues, other interactions were detected only in specific tissues, e.g., As-Cu in the kidney, Cd-Zn in the liver, and As-Mn, Cd-Mn, or Ni-Cu in the intestine. Increases of renal Pb and intestinal Cd by dietary Ni, and a decrease in bone As by dietary Pb were the most pronounced interactions between the toxic metals. The results demonstrate that potential target organs for the evaluation of metal exposure need to be carefully analyzed for interfering metal-metal interactions.

    9. 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

    10. 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.)

    11. 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.

    12. Method for preparing porous metal hydride compacts

      Science.gov (United States)

      Ron, M.; Gruen, D.M.; Mendelsohn, M.H.; Sheft, I.

      1980-01-21

      A method for preparing porous metallic-matrix hydride compacts which can be repeatedly hydrided and dehydrided without disintegration. A mixture of a finely divided metal hydride and a finely divided matrix metal is contacted with a poison which prevents the metal hydride from dehydriding at room temperature and atmospheric pressure. The mixture of matrix metal and poisoned metal hydride is then compacted under pressure at room temperature to form porous metallic-matrix hydride compacts.

    13. 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.

    14. Magnetic metallic multilayers

      Energy Technology Data Exchange (ETDEWEB)

      Hood, Randolph Quentin [Univ. of California, Berkeley, CA (United States)

      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.

    15. Autoradiography of metallic matrices

      International Nuclear Information System (INIS)

      Keller, N.A.

      1982-04-01

      One of the container designs being considered for the disposal of irradiated CANDU fuel bundles consists of a cylindrical titanium shell approximately 1.10 m in height and 0.84 m in diameter, into which is placed a basket fabricated from a close-packed array of thirty-seven 10 cm (4 in.) schedule 40 steel pipes. Two fuel bundles would be stacked into all but the central pipe, and the entire container filled with a low melting point metal. There is concern that shrinkage during solidification of this metal matrix may result in voids being present in the matrix near the outer shell of the container. One of the methods being considered to determine the presence of such voids is autoradiography. A theoretical study was carried out to determine the limitations of this technique. The results are discussed in detail in this report. It is concluded that while autoradiography appears feasible, it will require using a complex multi-detector system to detect voids of a reasonable size

    16. Vitrified metal finishing wastes

      Energy Technology Data Exchange (ETDEWEB)

      Bingham, P.A. [Immobilisation Science Laboratory, Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)]. E-mail: p.a.bingham@sheffield.ac.uk; Hand, R.J. [Immobilisation Science Laboratory, Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom)

      2005-03-17

      Durable phosphate glasses were formed by vitrifying waste filter cakes from two metal finishing operations. Some melts formed crystalline components during cooling. Compositional analysis of dried, heat treated and vitrified samples was made using energy-dispersive X-ray spectroscopy, X-ray fluorescence spectroscopy, inductively-coupled plasma spectroscopy and Leco induction furnace combustion analysis. Hydrolytic dissolution, measured by an adapted product consistency test, was reduced by up to 3 orders of magnitude upon heat treatment or vitrification, surpassing the performance of borosilicate glass in some cases. This was attributed to the high levels of iron and zinc in the wastes, which greatly improve the durability of phosphate glasses. One of the wastes arose from a metal phosphating process and was particularly suitable for vitrification due to its high P{sub 2}O{sub 5} content and favourable melting behaviour. The other waste, which arose from a number of processes, was less suitable as it had a low P{sub 2}O{sub 5} content and during heating it emitted harmful corrosive gases and underwent violent reactions. Substantial volume reductions were obtained by heat treatment and vitrification of both wastes. Compositions and performances of some vitrified wastes were comparable with those of glasses which are under consideration for the immobilisation of toxic and nuclear wastes.

    17. 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.

    18. 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.

    19. 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)

    20. 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

    1. Simulations of Recrystallization in Metals

      DEFF Research Database (Denmark)

      Godiksen, Rasmus Brauner

      2007-01-01

      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...... 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...... that improve the processing and properties of metals....

    2. Metal deposition using seed layers

      Science.gov (United States)

      Feng, Hsein-Ping; Chen, Gang; Bo, Yu; Ren, Zhifeng; Chen, Shuo; Poudel, Bed

      2013-11-12

      Methods of forming a conductive metal layers on substrates are disclosed which employ a seed layer to enhance bonding, especially to smooth, low-roughness or hydrophobic substrates. In one aspect of the invention, the seed layer can be formed by applying nanoparticles onto a surface of the substrate; and the metallization is achieved by electroplating an electrically conducting metal onto the seed layer, whereby the nanoparticles serve as nucleation sites for metal deposition. In another approach, the seed layer can be formed by a self-assembling linker material, such as a sulfur-containing silane material.

    3. 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...

    4. Antimicrobial Polymers with Metal Nanoparticles

      Directory of Open Access Journals (Sweden)

      Humberto Palza

      2015-01-01

      Full Text Available 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.

    5. 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

    6. 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 capacitor.

    7. 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)

    8. 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...

    9. Catalytic dehydrogenation of light alkanes on metals and metal oxides

      NARCIS (Netherlands)

      Sattler, Jesper J H B|info:eu-repo/dai/nl/328235601; Ruiz-Martinez, Javier|info:eu-repo/dai/nl/341386405; Santillan-Jimenez, Eduardo|info:eu-repo/dai/nl/323171958; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397

      2014-01-01

      A study is conducted to demonstrate catalytic dehydrogenation of light alkanes on metals and metal oxides. The study provides a complete overview of the materials used to catalyze this reaction, as dehydrogenation for the production of light olefins has become extremely relevant. Relevant factors,

    10. Making A Noble-Metal-On-Metal-Oxide Catalyst

      Science.gov (United States)

      Miller, Irvin M.; Davis, Patricia P.; Upchurch, Billy T.

      1989-01-01

      Catalyst exhibits superior performance in oxidation of CO in CO2 lasers. Two-step process developed for preparing platinum- or palladium-on-tin-oxide catalyst for recombination of CO and O2, decomposition products that occur in high-voltage discharge region of closed-cycle CO2 laser. Process also applicable to other noble-metal/metal-oxide combinations.

    11. 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

    12. 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

    13. Metal-in-metal localized surface plasmon resonance

      International Nuclear Information System (INIS)

      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.

    14. 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

    15. 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.

    16. [Metal ion concentrations in patients with metal-metal bearings in prostheses].

      Science.gov (United States)

      Kretzer, J P; Van Der Straeten, C; Sonntag, R; Müller, U; Streit, M; Moradi, B; Jäger, S; Reinders, J

      2013-08-01

      Increased wear leads to elevated systemic and local metal ion concentrations for patients treated with metal-on-metal bearings. The local metal ion content in the close environment of the joint replacement (e.g. joint aspirate or tissue) is several times higher compared to the systemic metal content (e.g. in blood or serum). As a result of increased metal ion levels, local and systemic effects, such as osteolysis, pseudotumors, sensitization or in rare cases toxicity may occur. Although the definition of a specific threshold to define clinical problems is difficult due to a lack of sensitivity, the systemic metal concentration is frequently measured clinically. Currently a threshold for cobalt and chromium between 4 µg/l and 7 µg/l is under debate. Very high levels (≥ 20 µg/l) or a steady increase over time should be a warning sign; however, metal ion levels should not be interpreted as a single diagnostic tool but rather in the entire context of the clinical, radiological and cross-sectional imaging, metal artefact reduction sequence (MARS) magnetic resonance imaging (MRI), ultrasound and computed tomography (CT) findings.

    17. Thin film hydrous metal oxide catalysts

      Science.gov (United States)

      Dosch, Robert G.; Stephens, Howard P.

      1995-01-01

      Thin film (metal oxide catalysts are prepared by 1) synthesis of a hydrous metal oxide, 2) deposition of the hydrous metal oxide upon an inert support surface, 3) ion exchange with catalytically active metals, and 4) activating the hydrous metal oxide catalysts.

    18. Creating bulk nanocrystalline metal.

      Energy Technology Data Exchange (ETDEWEB)

      Fredenburg, D. Anthony (Georgia Institute of Technology, Atlanta, GA); Saldana, Christopher J. (Purdue University, West Lafayette, IN); Gill, David D.; Hall, Aaron Christopher; Roemer, Timothy John (Ktech Corporation, Albuquerque, NM); Vogler, Tracy John; Yang, Pin

      2008-10-01

      Nanocrystalline and nanostructured materials offer unique microstructure-dependent properties that are superior to coarse-grained materials. These materials have been shown to have very high hardness, strength, and wear resistance. However, most current methods of producing nanostructured materials in weapons-relevant materials create powdered metal that must be consolidated into bulk form to be useful. Conventional consolidation methods are not appropriate due to the need to maintain the nanocrystalline structure. This research investigated new ways of creating nanocrystalline material, new methods of consolidating nanocrystalline material, and an analysis of these different methods of creation and consolidation to evaluate their applicability to mesoscale weapons applications where part features are often under 100 {micro}m wide and the material's microstructure must be very small to give homogeneous properties across the feature.

    19. 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)

    20. 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.

    1. 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.

    2. 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.

    3. 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)

    4. 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)

    5. 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,…

    6. 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..

    7. Superconductivity of metallic aluminum antimonide.

      Science.gov (United States)

      Wittig, J

      1967-02-10

      The high-pressure metallic phase of aluminunm antimnonide is super conducting [critical temperature T(c) (P approximately 125 kilobars) = 2.8 degrees +/-0.2 degrees K]. This transition temperature is significantly lower than the transition temperature of metallic germanium under an equivalent high pressure. A similar result had been previously found for superconducting indiumantimonide in comparison to tin.

    8. Electrochemical analysis of metal complexes

      NARCIS (Netherlands)

      Jong, de H.G.

      1987-01-01

      The present study is concerned with the electroanalytical chemistry of complexes of metals with large ligands. The main purpose was to develop quantitative descriptions of the voltammetric current-potential relation of metal complex systems with different diffusion coefficients of the

    9. Imaging metals in Caenorhabditis elegans.

      Science.gov (United States)

      Aschner, M; Palinski, C; Sperling, M; Karst, U; Schwerdtle, T; Bornhorst, J

      2017-04-19

      Systemic trafficking and storage of essential metal ions play fundamental roles in living organisms by serving as essential cofactors in various cellular processes. Thereby metal quantification and localization are critical steps in understanding metal homeostasis, and how their dyshomeostasis might contribute to disease etiology and the ensuing pathologies. Furthermore, the amount and distribution of metals in organisms can provide insight into their underlying mechanisms of toxicity and toxicokinetics. While in vivo studies on metal imaging in mammalian experimental animals are complex, time- and resource-consuming, the nematode Caenorhabditis elegans (C. elegans) provides a suitable comparative and complementary model system. Expressing homologous genes to those inherent to mammals, including those that regulate metal homeostasis and transport, C. elegans has become a powerful tool to study metal homeostasis and toxicity. A number of recent technical advances have been made in the development and application of analytical methods to visualize metal ions in C. elegans. Here, we briefly summarize key findings and challenges of the three main techniques and their application to the nematode, namely sensing fluorophores, microbeam synchrotron radiation X-ray fluorescence as well as laser ablation (LA) coupled to inductively coupled plasma-mass spectrometry (ICP-MS).

    10. Metal imaging in neurodegenerative diseases

      Science.gov (United States)

      Bourassa, Megan W.

      2014-01-01

      Metal ions are known to play an important role in many neurodegenerative diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), and prion diseases. In these diseases, aberrant metal binding or improper regulation of redox active metal ions can induce oxidative stress by producing cytotoxic reactive oxygen species (ROS). Altered metal homeostasis is also frequently seen in the diseased state. As a result, the imaging of metals in intact biological cells and tissues has been very important for understanding the role of metals in neurodegenerative diseases. A wide range of imaging techniques have been utilized, including X-ray fluorescence microscopy (XFM), particle induced X-ray emission (PIXE), energy dispersive X-ray spectroscopy (EDS), laser ablation inductively coupled mass spectrometry (LA-ICP-MS), and secondary ion mass spectrometry (SIMS), all of which allow for the imaging of metals in biological specimens with high spatial resolution and detection sensitivity. These techniques represent unique tools for advancing the understanding of the disease mechanisms and for identifying possible targets for developing treatments. In this review, we will highlight the advances in neurodegenerative disease research facilitated by metal imaging techniques. PMID:22797194

    11. (17) ACCUMULATION OF HEAVY METAL

      African Journals Online (AJOL)

      Adeyinka Odunsi

      . *Adelasoye, K. A. ... cassava leaf and assessed the effects of the metals on microbial populations along Ogbomoso-‐Oyo, high traffic density (HTD) (A) and Ogbomoso-‐Ife ..... Kumar (2014). Leaves of higher plants as indicators of heavy metal.

    12. 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.

    13. Model pseudopotential in simple metals

      International Nuclear Information System (INIS)

      Khanna, K.N.; Sharma, P.K.

      1980-01-01

      The model potential proposed by Sharma and Srivastava has been used to study the various properties of simple metals. New core radii have also been reported corresponding to three dielectric functions. For most metals, the model potential successfully describes the atomic properties. (author)

    14. 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...

    15. 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.

    16. 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.

    17. Joining ceramics, glass and metal

      International Nuclear Information System (INIS)

      Kraft, W.

      1989-01-01

      In many areas of electronics, engine manufacturing, machine and apparatus construction and aearospace, different combinations of materials such as ceramics/metal and glass/metal are gaining increasingly in importance. The proceedings cover the 53 papers presented to the 3rd International Conference on Joining Ceramics, Glass and Metal, held in Bad Nauheim (FRG) from April 26 to 28, 1989. The papers discuss problems and results under the following main topics of the conference: (1) Active brazing applied to non-oxide ceramics and oxide ceramics. (2) Diffusion bonding of metals and ceramics. (3) Friction welding, reaction bonding, and other joining methods. (4) Properties of metal-ceramic joints (as e.g. residual stress, fracture toughness, thermal stress) and various investigation methods for their determination. (MM) [de

    18. Heavy metal sorption by microalgae

      Energy Technology Data Exchange (ETDEWEB)

      Sandau, E. [IGV - Inst. fuer Getreideverarbeitung GmbH, Bergholz-Rehbruecke (Germany); Sandau, P. [IGV - Inst. fuer Getreideverarbeitung GmbH, Bergholz-Rehbruecke (Germany); Pulz, O. [IGV - Inst. fuer Getreideverarbeitung GmbH, Bergholz-Rehbruecke (Germany)

      1996-12-31

      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. [Detection of metal ions in hair after metal-metal hip arthroplasty].

      Science.gov (United States)

      Hernandez-Vaquero, D; Rodríguez de la Flor, M; Fernandez-Carreira, J M; Sariego-Muñiz, C

      2014-01-01

      There is an increase in the levels of metals in the serum and urine after the implantation of some models of metal-metal hip prosthesis. It has recently been demonstrated that there is an association between these levels and the levels found in hair. The aim of this study is to determine the presence of metals in hair, and to find out whether these change over time or with the removal of the implant. The levels of chromium, cobalt and molybdenum were determined in the hair of 45 patients at 3, 4, 5, and 6 years after a hip surface replacement. The mean age was 57.5 years, and two were female. Further surgery was required to remove the replacement and implant a new model with metal-polyethylene friction in 11 patients, 5 of them due to metallosis and a periarticular cyst. The mean levels of metals in hair were chromium 163.27 ppm, cobalt 61.98 ppm, and molybdenum 31.36 ppm, much higher than the levels found in the general population. A decrease in the levels of chromium (43.8%), molybdenum (51.1%), and cobalt (91.1%) was observed at one year in the patients who had further surgery to remove the prosthesis. High concentrations of metals in the hair are observed in hip replacements with metal-metal friction, which decrease when that implant is removed. The determination of metal ions in hair could be a good marker of the metal poisoning that occurs in these arthroplasty models. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

    1. 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.

    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. How to build a Bad Metal from good metal components

      Science.gov (United States)

      Arnason, Stephen; Hebard, Arthur

      1998-03-01

      One of the most fascinating sub-fields of contemporary condensed matter physics is the study of bad metals. A distinguishing characteristic of a bad metal is that its resistivity as a function of temperature increases linearly past the scale where one wou ld infer a scattering length comparable to the inter-atomic spacing (at this range the Boltzmann transport theory ceases to be self consistent). By contrast, good metals exhibit resistive saturation when the resistivity approaches this scale. We have grow n thin films composed of a good metal, Ag, that mimic the characteristics of bad metals, very high resistivities and lack of resistive saturation. We have characterised the microstructure that leads to this behavior with a novel application of electrostat ic force microscopy, EFM. This microstructure leads to an anomalous negative magnetoresistance, which is quadratic in the applied field.. Finally, we have identified a criterion which can be used to distinguish this mimicry from intrinsic bad metallicity, a criterion that is met by A_3C_60 (A=K,Rb), indicating that caution should be exercised before classifying these materials as bad metals.

    4. Method of making spherical metallic oxide and metallic carbide particles

      International Nuclear Information System (INIS)

      Zimmer, E.

      1976-01-01

      A method is described for making spherical metallic oxide and metallic carbide particles, especially particles consisting of fuel or breeder material such as oxide or carbide compounds of uranium, plutonium, thorium and the like with a diameter of from 0.1 to 1.5 millimeters, according to which an aqueous solution of a metallic nitrate or a metallic chloride or a mixture of metallic nitrates or metallic chlorides in which the metallic ions and anions are in a stoichiometric ratio to each other, is added dropwise to an organic phase. The method is characterized primarily in that the drops formed from the aqueous solution after congealing are washed in an aqueous solution containing ammonia and from 0.001 percent to 0.1 percent of a non-ionic surface active agent, especially an ethylene oxide condensate, enveloping the particles and preventing them from clumping during the following drying step. The hardened particles are dried in an air current having a temperature of from 150 to 300 0 C and an atmospheric moisture content corresponding to the degree of saturation of the air at a temperature of about from 20 to 50 0 C, and sintered at about 1300 0 C

    5. Method for preparing metal powder, device for preparing metal powder, method for processing spent nuclear fuel

      Science.gov (United States)

      Park, Jong-Hee [Clarendon Hills, IL

      2011-11-29

      A method for producing metal powder is provided the comprising supplying a molten bath containing a reducing agent, contacting a metal oxide with the molten bath for a time and at a temperature sufficient to reduce the metal in the metal oxide to elemental metal and produce free oxygen; and isolating the elemental metal from the molten bath.

    6. Blood metal ion concentrations in metal-on-metal total hip arthroplasty.

      Science.gov (United States)

      Ohtsuru, Tadahiko; Morita, Yuji; Murata, Yasuaki; Shimamoto, Shuji; Munakata, Yutaro; Kato, Yoshiharu

      2017-05-01

      The hip placement with a metal-on-metal (MOM) bearing has been used for both surface replacement and total hip arthroplasty (THA). Use of MOM bearing for hip replacement reduces the wear compared to conventional bearings. We prospectively assessed 30 patients who underwent unilateral MOM THA. A control group of 30 patients who underwent metal-on-polyethylene THA using the implants as the other group, except for bearing, were accessed. Blood samples were collected preoperatively and at 3- , 6- , 9- , 12- , 15- , 18- , and 24-month intervals. Changes in mean blood metal ion concentration were compared between the MOM and metal-on-polyethylene groups. A statistically significant positive correlation was observed between blood cobalt and chromium concentrations in all of the patients. The mean blood ion concentrations of the MOM were significantly higher than those of the metal-on-polyethylene. A statistically significant negative correlation was found between maximum blood cobalt concentration and cup version angle. The maximum blood chromium concentrations in the patients who had larger cup version angles were more likely to decrease. We considered that cup version angle is one of the factors that have the greatest effect on blood metal ion concentration, and the target cup version angle that did not induce an increase in blood metal ion concentrations was approximately 20°.

    7. Thermal conductivity of metal-metal microlaminate composites

      Science.gov (United States)

      Radhakrishna, M. C.; Doerr, H. J.; Deshpandey, C. V.; Bunshah, R. F.

      1989-01-01

      Microlaminate composites consisting of alternate layers of metal-metal, metal-ceramic and ceramic-ceramic exhibit anisotropy in thermal conductivity. Thermal conductivity in the direction perpendicular to the laminate plane is significantly lower than in the plane of the laminate. Results of the study on thermal conductivity of Ni-NiCoCrAlY and Ti-CoCrAlY microlaminate composites are presented. A semi-quantitative model explaining the thermal conductivity variation in the above systems as a function of number of layers is discussed. An expression correlating the experimental data with the calculated data for the above system is presented.

    8. 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.

    9. Catalysis using hydrous metal oxide ion exchanges

      Science.gov (United States)

      Dosch, Robert G.; Stephens, Howard P.; Stohl, Frances V.

      1985-01-01

      In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

    10. 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

    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. 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...

    13. PDTI metal alloy as a hydrogen or hydrocarbon sensitive metal

      Science.gov (United States)

      Hunter, Gary W. (Inventor)

      1996-01-01

      A hydrogen sensitive metal alloy contains palladium and titanium to provide a larger change in electrical resistance when exposed to the presence of hydrogen. The alloy can be used for improved hydrogen detection.

    14. Tensions on rare metals

      International Nuclear Information System (INIS)

      Rigaud, Ch.

      2010-01-01

      Rare earths that are used in the high or green technologies are facing short term shortages due to the steadily increasing demand and to the fact that some countries are reluctant to export them. For instance neodymium is used to make permanent magnets for the new generation of wind turbines. A year ago the price of neodymium was 14 dollar a kg while today it is priced at 40 dollar a kg, its production stagnates at 24000 tonnes a year which is just enough to meet the demand. The fear of shortage is high for thin layers in which tellurium, indium and germanium are involved. It is possible to act at any level of the production chain: to optimize the industrial production processes, to reduce the thickness of the thin layers, to recycle discarded equipment, to propose alternative solution: for instance the kesterite ore is studied in view of replacing indium in photovoltaic applications. The issue of rare earths or other rare metals begins to appear on government agenda. (A.C.)

    15. Diffusion welding of metals

      International Nuclear Information System (INIS)

      Susei, Shuzo; Matsui, Shigetomo; Yamada, Takeshi

      1978-01-01

      Recently, the materials with high heat resistance, corrosion resistance or strength have been developed, and some of them cannot be welded by ordinary method. Thereupon solid phase joining method is noticed, the mechanism of which is entirely different from conventional fusion welding. Among various solid phase joining methods, diffusion welding has many features. In case of joining same material, the joint can be made chemically and mechanically same as the parent material, and in case of joining different materials, joining can be made without forming any harmful compound, and the embrittlement of joints can be avoided. Kawasaki Heavy Industries Corp. has carried out a series of research on the diffusion welding of various metals, but in this paper, the characteristics of the joints of same material and different materials in titanium alloys are reported. The diffusion welding apparatus used adopts radiation heating using a tungsten heater and a hydraulic cylinder for pressing. The atmosphere of welded materials is kept in vacuum. The tested materials were industrial pure titanium TB 35 and Ti-6 Al-4 V alloy. The weldability of these materials by diffusion welding was studied, and it was confirmed that the joint efficiency of 100% was able to be obtained. However, for the practical application, more studies are required. (Kako, I.)

    16. Mixed valent metals

      Science.gov (United States)

      Riseborough, P. S.; Lawrence, J. M.

      2016-08-01

      We review the theory of mixed-valent metals and make comparison with experiments. A single-impurity description of the mixed-valent state is discussed alongside the description of the nearly-integer valent or Kondo limit. The degeneracy N of the f-shell plays an important role in the description of the low-temperature Fermi-liquid state. In particular, for large N, there is a rapid cross-over between the mixed-valent and the Kondo limit when the number of f electrons is changed. We discuss the limitations on the application of the single-impurity description to concentrated compounds such as those caused by the saturation of the Kondo effect and those due to the presence of magnetic interactions between the impurities. This discussion is followed by a description of a periodic lattice of mixed-valent ions, including the role of the degeneracy N. The article concludes with a comparison of theory and experiment. Topics covered include the single-impurity Anderson model, Luttinger’s theorem, the Friedel sum rule, the Schrieffer-Wolff transformation, the single-impurity Kondo model, Kondo screening, the Wilson ratio, local Fermi-liquids, Fermi-liquid sum rules, the Noziéres exhaustion principle, Doniach’s diagram, the Anderson lattice model, the Slave-Boson method, etc.

    17. Thermal conductivity of metals

      Science.gov (United States)

      Kazem, Sayyed M.

      1990-01-01

      The objective is to familiarize students with steady and unsteady heat transfer by conduction and with the effect of thermal conductivity upon temperature distribution through a homogeneous substance. The elementary heat conduction experiment presented is designed for associate degree technology students in a simple manner to enhance their intuition and to clarify many confusing concepts such as temperature, thermal energy, thermal conductivity, heat, transient and steady flows. The equipment set is safe, small, portable (10 kg) and relatively cheap (about $1200): the electric hot plate 2 kg (4.4 lb) for $175: the 24 channel selector and Thermocouple Digital Readout (Trendicator) 4.5 kg (10 lb) for about $1000; the three metal specimens (each of 2.5 cm diameter and 11 cm length), base plate and the bucket all about 3 kg (7 lb) for about $25. The experiment may take from 60 to 70 minutes. Although the hot plate surface temperature could be set from 90 to 370 C (maximum of 750 watts) it is a good practice to work with temperatures of 180 to 200 C (about 400 watts). They may experiment in squads of 2, 3 or even 4, or the instructor may demonstrate it for the whole class.

    18. Transition Metal Compounds Towards Holography

      Directory of Open Access Journals (Sweden)

      Volker Dieckmann

      2012-06-01

      Full Text Available We have successfully proposed the application of transition metal compounds in holographic recording media. Such compounds feature an ultra-fast light-induced linkage isomerization of the transition-metal–ligand bond with switching times in the sub-picosecond regime and lifetimes from microseconds up to hours at room temperature. This article highlights the photofunctionality of two of the most promising transition metal compounds and the photophysical mechanisms that are underlying the hologram recording. We present the latest progress with respect to the key measures of holographic media assembled from transition metal compounds, the molecular embedding in a dielectric matrix and their impressive potential for modern holographic applications.

    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. Metal-clad waveguide sensors

      DEFF Research Database (Denmark)

      Skivesen, Nina

      by Qi et al [Zm Qi et al, Sens. Actuators B 81, 2002] before, however the sensing principle we present results in a broad detection range from gasses to solid materials and is different from the principle suggested by Qi et al with a highlylimited detection range. Metal-clad waveguide sensors......, where single cell detection isshown by use of the metal-clad waveguide sensors.......This work concerns planar optical waveguide sensors for biosensing applications, with the focus on deep-probe sensing for micron-scale biological objects like bacteria and whole cells. In the last two decades planar metal-clad waveguides have been brieflyintroduced in the literature applied...

    2. 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....

    3. 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....

    4. Novel metals and metal complexes as platforms for cancer therapy.

      Science.gov (United States)

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

      2010-06-01

      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, coordination complexes, either as drugs or prodrugs, become very attractive probes as potential anticancer agents. The use of metals and their salts for medicinal purposes, from iatrochemistry to modern day, has been present throughout human history. The discovery of cisplatin, cis-[Pt(II) (NH(3))(2)Cl(2)], was a defining moment which triggered the interest in platinum(II)- and other metal-containing complexes as potential novel anticancer drugs. Other interests in this field address concerns for uptake, toxicity, and resistance to metallodrugs. This review article highlights selected metals that have gained considerable interest in both the development and the treatment of cancer. For example, copper is enriched in various human cancer tissues and is a co-factor essential for tumor angiogenesis processes. However the use of copper-binding ligands to target tumor copper could provide a novel strategy for cancer selective treatment. The use of nonessential metals as probes to target molecular pathways as anticancer agents is also emphasized. Finally, based on the interface between molecular biology and bioinorganic chemistry the design of coordination complexes for cancer treatment is reviewed and design strategies and mechanisms of action are discussed.

    5. Microgravity metal processing: from undercooled liquids to bulk metallic glasses

      Science.gov (United States)

      Hofmann, Douglas C; Roberts, Scott N

      2015-01-01

      Bulk metallic glasses (BMGs) are a novel class of metal alloys that are poised for widespread commercialization. Over 30 years of NASA and ESA (as well as other space agency) funding for both ground-based and microgravity experiments has resulted in fundamental science data that have enabled commercial production. This review focuses on the history of microgravity BMG research, which includes experiments on the space shuttle, the ISS, ground-based experiments, commercial fabrication and currently funded efforts. PMID:28725709

    6. 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.

    7. 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.

    8. Organic Superconductor, Made without Metals.

      Science.gov (United States)

      Science News, 1980

      1980-01-01

      The discovery of a superconducting organic compound is reported. The compound, (TMTSF)-2, has no metal in its composition, and the author believes that it is the precursor of a family of superconducting organics. (Author/SA)

    9. Metal structures with parallel pores

      Science.gov (United States)

      Sherfey, J. M.

      1976-01-01

      Four methods of fabricating metal plates having uniformly sized parallel pores are studied: elongate bundle, wind and sinter, extrude and sinter, and corrugate stack. Such plates are suitable for electrodes for electrochemical and fuel cells.

    10. Metals and Ceramics Information Center.

      Science.gov (United States)

      1981-07-01

      Specialization CURRENT AWARENESS BULLETIN (Continued) Noton, B. R. Program Manager Report on Conference Pattee , H. E. Staff Metallurgist Metals...Welding Duckworth, W. H. Staff Engineer Ceramics Pattee , H. Staff Engineer Welding HANDBOOKS /DATABOOKS Hucek, H. J. Staff Metallurgist Mechanical

    11. 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

    12. 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

    13. 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...

    14. 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.

    15. 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.

    16. The structure of expanding metals

      International Nuclear Information System (INIS)

      Winter, R.; Hensel, F.; Bodensteiner, T.; Glaeser, W.

      1985-01-01

      The liquid metal structure is investigated by neutron diffraction up to 2000 K and 200 bar by determining the structure factor SCQJ for liquid cesium and rubidium. The rather complicated experimental equipment is described. (BHO)

    17. Transition metal contacts to graphene

      Energy Technology Data Exchange (ETDEWEB)

      Politou, Maria, E-mail: Maria.Politou@imec.be; De Gendt, Stefan; Heyns, Marc [KU Leuven, 3001 Leuven (Belgium); imec, Kapeldreef 75, 3001 Leuven (Belgium); Asselberghs, Inge; Radu, Iuliana; Conard, Thierry; Richard, Olivier; Martens, Koen; Huyghebaert, Cedric; Tokei, Zsolt [imec, Kapeldreef 75, 3001 Leuven (Belgium); Lee, Chang Seung [SAIT, Samsung Electronics Co., Suwon 443-803 (Korea, Republic of); Sayan, Safak [imec, Kapeldreef 75, 3001 Leuven (Belgium); Intel Corporation, 2200 Mission College Blvd, Santa Clara, California 95054 (United States)

      2015-10-12

      Achieving low resistance contacts to graphene is a common concern for graphene device performance and hybrid graphene/metal interconnects. In this work, we have used the circular Transfer Length Method (cTLM) to electrically characterize Ag, Au, Ni, Ti, and Pd as contact metals to graphene. The consistency of the obtained results was verified with the characterization of up to 72 cTLM structures per metal. Within our study, the noble metals Au, Ag and Pd, which form a weaker bond with graphene, are shown to result in lower contact resistance (Rc) values compared to the more reactive Ni and Ti. X-ray Photo Electron Spectroscopy and Transmission Electron Microscopy characterization for the latter have shown the formation of Ti and Ni carbides. Graphene/Pd contacts show a distinct intermediate behavior. The weak carbide formation signature and the low Rc values measured agree with theoretical predictions of an intermediate state of weak chemisorption of Pd on graphene.

    18. Fluoropolymer metallization for microelectronic applications

      Science.gov (United States)

      Sacher, E.

      1994-11-01

      One of the most important requirements for the fastest microelectronic devices in present use, and for the even faster devices for future use, is the reduction of the signal interconnection delay time to a small fraction of all the switching delay times. The interconnection delay time is the product of the resistance of the metal interconnection and the capacitance of the associated dielectric. One method of lowering this delay time is the use of multilayer devices incorporating low resistivity metals (e.g., Cu) and low capacitance dielectrics (e.g. fluoropolymers). Among the many problems faced in the construction of multilayer devices from these materials is the lack of metal adhesion to flouropolymers. This article attempts to put into perspective the problem of metal adhesion to fluoropolymers by addressing the reason for its necessity. Reviewing the critical properties and techniques and discussing the presently available results.

    19. 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.

    20. Toxic metal pollution in Africa.

      Science.gov (United States)

      Nriagu, J O

      1992-06-30

      The available information suggests that the concentrations of toxic metals in many ecosystems of Africa are reaching unprecedented levels. Because of the heavy load of contaminated dusts in the air of the overcrowded cities, the ambient concentrations of toxic metals are now among the highest being reported anywhere. Lead pollution from the increasing number of automobiles and cottage industries represents a major health hazard, and it is estimated that 15-30% of the infants in some urban areas may already be suffering from lead poisoning. The cultural and lifestyle determinants of lead exposure and the greater susceptibility of African populations to environmental metal poisoning are highlighted. The suggestion is made that the environmental health criteria for toxic metals in the developed countries may not provide adequate protection for many African communities.

    1. 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.

    2. 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

    3. 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)

    4. 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....

    5. Metal complexes of phosphinic acids

      International Nuclear Information System (INIS)

      Das, P.N.M.; Kuchen, W.; Keck, H.; Haegele, G.

      1977-01-01

      Pr(III), Nd(III) and Eu(III) complexes of dimethyldithiophosphinic acid have been prepared. Their properties and structures have been studied using elemental analysis, molecular weight determination, IR, UV, mass, NMR, magnetic studies, etc. It is found that these metals form neutral complexes of the type ML 3 where L is a deprotonated bidentate dimethyldithiophosphinic acid molecule. The coordination number exhibited by these metals in this case is six. Octahedral structures have been assigned to these complexes. (author)

    6. Transport Properties of Liquid Metals

      International Nuclear Information System (INIS)

      Kart, H.H.

      2004-01-01

      Transport properties of Pd, Ag pure metals and their binary alloys are investigated by using molecular dynamics simulation. Quantum Sutton-Chen (Q-SC) many-body potential is used to define the interactions between the atoms. The effects of temperature and concentration on the transport properties such as diffusion and viscosity of the metals are analysed. The simulation results are in good agreement with the experimental and theoretical values

    7. Actively convected liquid metal divertor

      Science.gov (United States)

      Shimada, Michiya; Hirooka, Yoshi

      2014-12-01

      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.

    8. 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...

    9. 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....

    10. 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

    11. 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.

    12. 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.

    13. 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.

    14. Optical transmissivity of metallic nanowires

      Science.gov (United States)

      Nairat, Mazen S.

      2017-08-01

      Optical transmissivity and reflectivity of one dimensional array of metallic nanowires embedded in transparent dielectric is characterized. i employ wave optics simulation to analyze the optical field distribution in both the dielectric and the nanowires. The results indicate that the transmissivity and reflectivity depend on the polarization states of the incident light. The metallic nanowires matrix transmit in-plane polarization but block light out at of-plane polarization.

    15. 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

    16. 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.

    17. 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.

    18. 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.

    19. 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.

    20. Horizontal electromagnetic casting of thin metal sheets

      Science.gov (United States)

      Hull, John R.; Lari, Robert J.; Praeg, Walter F.; Turner, Larry R.

      1987-01-01

      Thin metal sheets are cast by magnetically suspending molten metal deposited within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled to form a solid metal sheet. Magnetic flux increases as the molten metal sheet moves downward and decreases as the molten metal sheet moves upward to stabilize the sheet and maintain it in equilibrium as it is linearly displaced and solidified by cooling gases. A conducting shield is electrically coupled to the molten metal sheet by means of either metal sheet engaging rollers or brushes on the solidified metal, and by means of an electrode in the vessel containing the molten metal thereby providing a return path for the eddy currents induced in the metal sheet by the AC coil generated magnetic flux. Variation in the geometry of the conducting shield allows the magnetic flux between the metal sheet and the conducting shield to be varied and the thickness in surface quality of the metal sheet to be controlled. Side guards provide lateral containment for the molten metal sheet and stabilize and shape the magnetic field while a leader sheet having electromagnetic characteristics similar to those of the metal sheet is used to start the casting process and precedes the molten metal sheet through the magnet and forms a continuous sheet therewith. The magnet may be either U-shaped with a single racetrack coil or may be rectangular with a pair of facing bedstead coils.

    1. Horizontal electromagnetic casting of thin metal sheets

      Energy Technology Data Exchange (ETDEWEB)

      Hull, John R. (Hinsdale, IL); Lari, Robert J. (Aurora, IL); Praeg, Walter F. (Palos Park, IL); Turner, Larry R. (Naperville, IL)

      1988-01-01

      Thin metal sheets are cast by magnetically suspending molten metal deposited within a ferromagnetic yoke and between AC conducting coils and linearly displacing the magnetically levitated liquid metal while it is being cooled to form a solid metal sheet. Magnetic flux increases as the molten metal sheet moves downward and decreases as the molten metal sheet moves upward to stabilize the sheet and maintain it in equilibrium as it is linearly displaced and solidified by cooling gases. A conducting shield is electrically coupled to the molten metal sheet by means of either metal sheet engaging rollers or brushes on the solidified metal, and by means of an electrode in the vessel containing the molten metal thereby providing a return path for the eddy currents induced in the metal sheet by the AC coil generated magnetic flux. Variation in the geometry of the conducting shield allows the magnetic flux between the metal sheet and the conducting shield to be varied and the thickness in surface quality of the metal sheet to be controlled. Side guards provide lateral containment for the molten metal sheet and stabilize and shape the magnetic field while a leader sheet having electromagnetic characteristics similar to those of the metal sheet is used to start the casting process and precedes the molten metal sheet through the magnet and forms a continuous sheet therewith. The magnet may be either U-shaped with a single racetrack coil or may be rectangular with a pair of facing bedstead coils.

    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. Dispersion enhanced metal/zeolite catalysts

      Science.gov (United States)

      Sachtler, Wolfgang M. H.; Tzou, Ming-Shin; Jiang, Hui-Jong

      1987-01-01

      Dispersion stabilized zeolite supported metal catalysts are provided as bimetallic catalyst combinations. The catalyst metal is in a reduced zero valent form while the dispersion stabilizer metal is in an unreduced ionic form. Representative catalysts are prepared from platinum or nickel as the catalyst metal and iron or chromium dispersion stabilizer.

    4. Metal salt catalysts for enhancing hydrogen spillover

      Science.gov (United States)

      Yang, Ralph T; Wang, Yuhe

      2013-04-23

      A composition for hydrogen storage includes a receptor, a hydrogen dissociating metal doped on the receptor, and a metal salt doped on the receptor. The hydrogen dissociating metal is configured to spill over hydrogen to the receptor, and the metal salt is configured to increase a rate of the spill over of the hydrogen to the receptor.

    5. 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.

    6. 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

    7. Embrittlement by liquid and solid metals

      International Nuclear Information System (INIS)

      Kamdar, M.H.

      1984-01-01

      This volume presents research on the phenomena of both liquid- and solid-metal induced embrittlement of metals and their occurrence in many important industries. In this book, review papers are presented on liquid-metal embrittlement, solid-metal embrittlement, and liquid- and solid-metal embrittlement of industrial metals and alloys. In addition, several papers presented cover parts of extensive investigations at the General Electric Company concerning liquid- and solid-metal embrittlement of zirconium nuclear fuel cladding tubes and possible means for preventing embrittlement of zirconium

    8. Valence-Bond Concepts in Coordination Chemistry and the Nature of Metal-Metal Bonds.

      Science.gov (United States)

      Pauling, Linus; Herman, Zelek S.

      1984-01-01

      Discusses the valence-bond method, applying it to some coordination compounds of metals, especially those involving metal-metal bonds. Suggests that transition metals can form as many as nine covalent bonds, permitting valence-theory to be extended to transition metal compounds in a more effective way than has been possible before. (JN)

    9. A Rh III-N-heterocyclic carbene complex from metal-metal singly ...

      Indian Academy of Sciences (India)

      Metal-metal singly bonded [Rh2(CO)4(acac)2][OTf]2 (1) has been synthesized and characterized by spectroscopic and analytical techniques. A density functional theory ... to each rhodium. This work demonstrates the general utility of the metal-metal bonded compounds for the easy synthesis of metal-NHC compounds.

    10. Mesoporous metal oxide graphene nanocomposite materials

      Energy Technology Data Exchange (ETDEWEB)

      Liu, Jun; Aksay, Ilhan A.; Kou, Rong; Wang, Donghai

      2016-05-24

      A nanocomposite material formed of graphene and a mesoporous metal oxide having a demonstrated specific capacity of more than 200 F/g with particular utility when employed in supercapacitor applications. A method for making these nanocomposite materials by first forming a mixture of graphene, a surfactant, and a metal oxide precursor, precipitating the metal oxide precursor with the surfactant from the mixture to form a mesoporous metal oxide. The mesoporous metal oxide is then deposited onto a surface of the graphene.

    11. Method of bonding metals to ceramics

      Science.gov (United States)

      Maroni, V.A.

      1991-04-23

      A ceramic or glass having a thin layer of silver, gold or alloys thereof at the surface thereof is disclosed. A first metal is bonded to the thin layer and a second metal is bonded to the first metal. The first metal is selected from the class consisting of In, Ga, Sn, Bi, Zn, Cd, Pb, Tl and alloys thereof, and the second metal is selected from the class consisting of Cu, Al, Pb, Au and alloys thereof. 3 figures.

    12. Plant transporters involved in heavy metal homeostasis

      OpenAIRE

      Dorina Podar

      2010-01-01

      Transition metal ions (predominately manganese, iron, cobalt, nickel, copper and zinc) havean array of catalytic and regulatory roles in the growth and development of all living organisms.However, an excess of these metal ions can also be toxic to any life form and therefore every cell andwhole organism needs to maintain the concentration of these essential nutrient metals within a narrowrange: a process known as metal homeostasis. Heavy metal ions are taken up into cells by selectivetranspor...

    13. Metal-induced crystallization fundamentals and applications

      CERN Document Server

      Wang, Zumin; Mittemeijer, Eric J

      2014-01-01

      Introduction to Metal-Induced CrystallizationAtomic Mechanisms and Interface Thermodynamics of Metal-Induced Crystallization of Amorphous Semiconductors at Low TemperaturesThermodynamics and Kinetics of Layer Exchange upon Low-Temperature Annealing Amorphous Si/Polycrystalline Al Layered StructuresMetal-Induced Crystallization by Homogeneous Insertion of Metallic Species in Amorphous SemiconductorsAluminum-Induced Crystallization: Applications in Photovoltaic TechnologiesApplications of Metal-Induced Crystallization for Advanced Flat-Panel DisplaysLaser-Assisted Meta

    14. 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

    15. Laser welding of sheet metals

      Science.gov (United States)

      Xie, Jian

      Laser welding of sheet metals is an important application of high power lasers, and has many advantages over conventional welding techniques. Laser welding has a great potential to replace other welding technique in the car-body manufacturing because of high laser weld quality and relatively low manufacturing cost associated with the laser technique. However, a few problems related to the laser welding of sheet metals limit its applications in industries. To have a better understanding of the welding process, laser welding experimental studies and theoretical analysis are necessary. Temperature-dependent absorptivities of various metals are obtained theoretically for COsb2, COIL (Chemical Oxygen-Iodine Laser) and Nd:YAG lasers. It is found that the absorptivities for COIL and Nd:YAG lasers are 2.84 and 3.16 times higher than for the COsb2 laser, and the absorptivity increases with increasing temperature of the metals. Surface roughness and oxide films can enhance the absorption significantly. The reflectivity of as-received steel sheets decreases from 65-80% to 30-40% with surface oxide films for COsb2 lasers. Laser welding experiments show that the tensile strengths of the weld metals are higher than the base metals. For samples with surface oxide films, the oxygen concentration in the weld metals is found to be higher than in the specimens without oxidation, and the toughness of the weld metals is degraded. When steel powders are added to bridge the gap between two sheets, the oxygen content in the weld metals decreases and the toughness increases. A mathematical model is developed for the melt depth due to a stationary laser beam. The model results show that the melt depth increases rapidly with time at the beginning of laser irradiation and then increases slowly. Also, the melt depth is found to increase rapidly with laser intensities and then increases slowly for higher intensity. The average rate of melting and the times to reach the melting and boiling

    16. Zone refining of plutonium metal

      International Nuclear Information System (INIS)

      Blau, M.S.

      1994-08-01

      The zone refining process was applied to Pu metal containing known amounts of impurities. Rod specimens of plutonium metal were melted into and contained in tantalum boats, each of which was passed horizontally through a three-turn, high-frequency coil in such a manner as to cause a narrow molten zone to pass through the Pu metal rod 10 times. The impurity elements Co, Cr, Fe, Ni, Np, U were found to move in the same direction as the molten zone as predicted by binary phase diagrams. The elements Al, Am, and Ga moved in the opposite direction of the molten zone as predicted by binary phase diagrams. As the impurity alloy was zone refined, δ-phase plutonium metal crystals were produced. The first few zone refining passes were more effective than each later pass because an oxide layer formed on the rod surface. There was no clear evidence of better impurity movement at the slower zone refining speed. Also, constant or variable coil power appeared to have no effect on impurity movement during a single run (10 passes). This experiment was the first step to developing a zone refining process for plutonium metal

    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. Plasmon filters and resonators in metal-insulator-metal waveguides.

      Science.gov (United States)

      Neutens, P; Lagae, L; Borghs, G; Van Dorpe, P

      2012-02-13

      We present the numerical and experimental demonstration of plasmonic Bragg filters and resonators inside metal-insulator-metal (MIM) waveguides. The presented filters and resonators are fabricated using standard top down lithography methods. The optical bandgap of the integrated Bragg filters is experimentally observed and its optical properties are investigated as a function of the grating pitch and the number of grating periods. Transmission filters based on a nanocavity resonance were measured, obtaining Q-factors above 30. Tuning of the cavity wavelength was experimentally achieved by varying the cavity length.

    19. 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

    20. 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.

    1. [Application of UV spectroscopy in structural studies of metal centre of metal-protein].

      Science.gov (United States)

      Liang, H; Zhou, Y; Shen, P

      1997-02-01

      The principle of UV spectroscopy applied in structural studies of metal centre of complexes is introduced in this paper. Several examples prove that such spectroscopy is an effective technical method in structural studies of metal centre of metal-protein.

    2. 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...

    3. 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...

    4. Anodematerials for Metal Hydride Batteries

      DEFF Research Database (Denmark)

      Jensen, Jens Oluf

      1997-01-01

      This report describes the work on development of hydride forming alloys for use as electrode materials in metal hydride batteries. The work has primarily been concentrated on calcium based alloys derived from the compound CaNi5. This compound has a higher capacity compared with alloys used in today...... was developed. The parameters milling time, milling intensity, number of balls and form of the alloying metals were investigated. Based on this a final alloying technique for the subsequent preparation of electrode materials was established. The technique comprises milling for 4 hours twice possibly followed...... by annealing at 700°C for 12 hours. The alloys appeared to be nanocrystalline with an average crystallite size around 10 nm before annealing. Special steel containers was developed for the annealing of the metal powders in inert atmosphere. The use of various annealing temperatures was investigated...

    5. 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.

    6. 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

    7. 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

    8. Nuclear acoustic resonance in metals

      International Nuclear Information System (INIS)

      Mueller, V.; Bartell, U.

      1979-01-01

      A comprehensive quantum theoretical treatment of nuclear acoustic resonance (NAR) in metals is presented for the first time. Basic equations describing the NAR-absorption and NAR-dispersion are derived from the sound induced perturbation Hamiltonian ih(t) by applying a generalized form of the 'Kubo susceptibility'. It is shown that in metals, where a sound wave may induce nuclear magnetic dipole and nuclear electric quadrupole transitions simultaneously, the appearance of interference terms enables one to determine not only the absolute values but also the signs of the gradient-elastic tensor components. Explicit expressions are displayed for the dipolar, quadrupolar and interference contributions to the generalized NAR susceptibility in cubic metals. As an example the derivative of the expected 93 Nb NAR-absorption line ( Δm =1) is calculated for different signs of the gradient elastic tensor component S 44 . (orig.) [de

    9. Thin films of mixed metal compounds

      Science.gov (United States)

      Mickelsen, R.A.; Chen, W.S.

      1985-06-11

      Disclosed is a thin film heterojunction solar cell, said heterojunction comprising a p-type I-III-IV[sub 2] chalcopyrite substrate and an overlying layer of an n-type ternary mixed metal compound wherein said ternary mixed metal compound is applied to said substrate by introducing the vapor of a first metal compound to a vessel containing said substrate from a first vapor source while simultaneously introducing a vapor of a second metal compound from a second vapor source of said vessel, said first and second metals comprising the metal components of said mixed metal compound; independently controlling the vaporization rate of said first and second vapor sources; reducing the mean free path between vapor particles in said vessel, said gas being present in an amount sufficient to induce homogeneity of said vapor mixture; and depositing said mixed metal compound on said substrate in the form of a uniform composition polycrystalline mixed metal compound. 5 figs.

    10. 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.

    11. 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)

    12. 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.

    13. BioMe: biologically relevant metals

      Science.gov (United States)

      Tus, Alan; Rakipović, Alen; Peretin, Goran; Tomić, Sanja; Šikić, Mile

      2012-01-01

      In this article, we introduce BioMe (biologically relevant metals), a web-based platform for calculation of various statistical properties of metal-binding sites. Users can obtain the following statistical properties: presence of selected ligands in metal coordination sphere, distribution of coordination numbers, percentage of metal ions coordinated by the combination of selected ligands, distribution of monodentate and bidentate metal-carboxyl, bindings for ASP and GLU, percentage of particular binuclear metal centers, distribution of coordination geometry, descriptive statistics for a metal ion–donor distance and percentage of the selected metal ions coordinated by each of the selected ligands. Statistics is presented in numerical and graphical forms. The underlying database contains information about all contacts within the range of 3 Å from a metal ion found in the asymmetric crystal unit. The stored information for each metal ion includes Protein Data Bank code, structure determination method, types of metal-binding chains [protein, ribonucleic acid (RNA), deoxyribonucleic acid (DNA), water and other] and names of the bounded ligands (amino acid residue, RNA nucleotide, DNA nucleotide, water and other) and the coordination number, the coordination geometry and, if applicable, another metal(s). BioMe is on a regular weekly update schedule. It is accessible at http://metals.zesoi.fer.hr. PMID:22693222

    14. Homogeneous catalysis by transition metals

      International Nuclear Information System (INIS)

      Masters, K.

      1983-01-01

      Fundamentals of homogeneous catalysis by metal complex aAe presented in the monograph along with the mechanisms of practically all types of catalytic reactions proceeding in the presence of transition metal complexes. In particular, considered are: catalytic cycles for olefin hydrogenation in the presence of Ru(2) complex; for alkene epoxidation catalyzed by Mo(6); for alkene metathesis reaction catalyzed by Ta and W compounds. Catalytic systems on the basis of Zr, Mo, W, Ru complexes being in the stage of development of the processes of nitrogen fixation reductive oligomerization alkene activation are described. Bibliography contains more than 400 references

    15. Recent advances in metal carcinogenesis

      Energy Technology Data Exchange (ETDEWEB)

      Sunderman, F.W. Jr.

      Recent advances in metal carcinogenesis are comprehensively reviewed, including (a) epidemiological and clinical aspects, (b) carcinogenesis bioassays, (c) bacterial mutagenesis, (d) mammalian cell mutagenesis, (e) chromosomal damage, (f) mammalian cell transformation, (g) microsomal metabolism, (h) DNA strandbreaks and crosslinks, (i) DNA polymerase infidelity, (j) RNA strand initiation, and (k) helical transition of B-DNA to Z-DNA. Based upon these observations, several hypotheses are proposed for the molecular pathogenesis of carcinogenesis by metal compounds. These hypotheses are amenable to experimental test by existing techniques of molecular biology.

    16. MOD silver metallization for photovoltaics

      Science.gov (United States)

      Vest, G. M.; Vest, R. W.

      1985-01-01

      The feasibility of utilizing metallo-organic decomposition (MOD) silver inks were investigated for front contact metallization of solar cells. Generic synthesis procedures were developed for all metallo-organic compounds investigated. Silver neodecanoate was found to be the most suitable silver metallo-organic compound for use in thick film inks, but the quality of the inks was found to be highly dependent on its purity. Although neither the process nor inks were completely optimized for solar cell front contact metallization, they show great promise for this application.

    17. 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.

    18. 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)

    19. 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

    20. Stabilization of electrocatalytic metal nanoparticles at metal-metal oxide-graphene triple junction points.

      Science.gov (United States)

      Kou, Rong; Shao, Yuyan; Mei, Donghai; Nie, Zimin; Wang, Donghai; Wang, Chongmin; Viswanathan, Vilayanur V; Park, Sehkyu; Aksay, Ilhan A; Lin, Yuehe; Wang, Yong; Liu, Jun

      2011-03-02

      Carbon-supported precious metal catalysts are widely used in heterogeneous catalysis and electrocatalysis, and enhancement of catalyst dispersion and stability by controlling the interfacial structure is highly desired. Here we report a new method to deposit metal oxides and metal nanoparticles on graphene and form stable metal-metal oxide-graphene triple junctions for electrocatalysis applications. We first synthesize indium tin oxide (ITO) nanocrystals directly on functionalized graphene sheets, forming an ITO-graphene hybrid. Platinum nanoparticles are then deposited, forming a unique triple-junction structure (Pt-ITO-graphene). Our experimental work and periodic density functional theory (DFT) calculations show that the supported Pt nanoparticles are more stable at the Pt-ITO-graphene triple junctions. Furthermore, DFT calculations suggest that the defects and functional groups on graphene also play an important role in stabilizing the catalysts. These new catalyst materials were tested for oxygen reduction for potential applications in polymer electrolyte membrane fuel cells, and they exhibited greatly enhanced stability and activity.

    1. 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.)

    2. Relevance of Orbital Interactions and Pauli Repulsion in the Metal-Metal Bond of Coinage Metals.

      Science.gov (United States)

      Brands, Maria B; Nitsch, Jörn; Guerra, Célia Fonseca

      2018-03-05

      The importance of relativity and dispersion in metallophilicity has been discussed in numerous studies. The existence of hybridization in the bonding between closed shell d 10 -d 10 metal atoms has also been speculated, but the presence of attractive MO interaction in the metal-metal bond is still a matter of an ongoing debate. In this comparative study, a quantitative molecular orbital analysis and energy decomposition is carried out on the metallophilic interaction in atomic dimers (M + ···M + ) and molecular perpendicular [H 3 P-M-X] 2 (where M = Cu, Ag, and Au; X = F, Cl, Br, and I). Our computational studies prove that besides the commonly accepted dispersive interactions, orbital interactions and Pauli repulsion also play a crucial role in the strength and length of the metal-metal bond. Although for M + ···M + the orbital interaction is larger than the Pauli repulsion, leading to a net attractive MO interaction, the bonding mechanism in perpendicular [H 3 P-M-X] dimers is different due to the larger separation between the donor and acceptor orbitals. Thus, Pauli repulsion is much larger, and two-orbital, four-electron repulsion is dominant.

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

      Indian Academy of Sciences (India)

      Thin films based on two very different metal-organic systems are developed and some nonlinear optical ... capability of the nanoparticle-embedded polymer film is demonstrated. Keywords. Polar crystal; uniaxial ... systems promising candidates for a wide range of electronic, magnetic and optical applications. However ...

    4. Synthesis of arsenic transition metal sulfides and metal arsenides

      Energy Technology Data Exchange (ETDEWEB)

      Singhal, G.H.; Brown, L.D.; Ryan, D.F. [Exxon Research & Development Labs, Baton Rouge, LA (United States)

      1993-12-31

      One of the chief problems in upgrading shale oil is the presence of inherent arsenic which is known to poison downstream catalysts. Highly dispersed transition metal sulfides formed in situ from the decomposition of dithiocarbamate (DTC) complexes of transition metals show excellent potential as dearsenation agents. The authors have studied the reaction of these sulfides with various arsenic compositions and characterized the metal arsenides and arsenic metal sulfides formed as well as the ease of their formation. Thus, the reaction of bis(butyldithiocarbamato)Ni, (NiBuDTC) with model compounds was very facile and gave NiAs, NiAsS, and NiAs2=xSx. In general the effectiveness of the sulfides for dearsenation followed the sequence Ni>Mo{much_gt}Co, while iron sulfides were totally ineffective. Based upon these results, tests were run in autoclaves (as well as a fixed-bed flow-through unit) with NiBuDTC and shale oil having 73 ppm inherent As. Under optimum conditions, dearsenation down to les than 1 ppm was obtained.

    5. Studies of Metal-Metal Bonded Compounds in Catalysis

      Energy Technology Data Exchange (ETDEWEB)

      Berry, John [University of Wisconsin-Madison

      2018-01-19

      The focus in this grant period has been on the preparation and study of compounds containing two metals (M) and a reactive main group fragment (E) aligned in a M–M=E linear array. These structures contain multiple bonds that interconnect the M and E groups, and are structures that had been proposed, but never observed, before our work.

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

      Indian Academy of Sciences (India)

      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 form perfectly polar assemblies in their crystalline state are found to organize as uniaxially oriented crystallites in vapor deposited thin films on glass substrate.

    7. Accumulation of heavy metals from single and mixed metal solutions ...

      African Journals Online (AJOL)

      The usefulness of the intertidal gastropod Tympanotonus fuscatus L as a biomonitor of heavy metals in tropical estuaries was assessed. The periwinkles were collected from a site in the upper Bonny Estuary, Southern Nigeria and exposed in a series of experiments either singly or binary mixtures to copper, zinc and ...

    8. Eficácia da N-butilescopolamina e dipirona sódica associadas ao cetoprofeno no alívio da dor pós-operatória de pacientes submetidas a duas técnicas diferentes de laqueadura por laparoscopia Eficacia de la N-butilescopolamina y dipirona sódica asociadas al cetoprofeno en el alivio del dolor pos-operatorio de pacientes sometidas a dos técnicas diferentes de laqueadura por laparoscopia Efficacy of N-butylscopolamine and sodium dipirone associated to ketoprofen for postoperative pain relief of patients submitted to two different laparoscopic sterilization techniques

      Directory of Open Access Journals (Sweden)

      Eliana Marisa Ganem

      2005-08-01

      de G1 e 16% de G2 necessitaram de tramadol em algum momento do estudo. CONCLUSÕES: A N-butilescopolamina e a dipirona sódica associadas ao cetoprofeno mostraram ser alternativa de analgesia pós-operatória quando a laqueadura é realizada com a técnica de diatermia.JUSTIFICATIVA Y OBJETIVOS: La laqueadura laparoscópica (LL es uno de los procedimientos más dolorosos y la intensidad del dolor varia con la técnica seleccionada, siendo más intensa con la técnica de oclusión de las trompas uterinas con anillo. Las pacientes sometidas a la LL refieren dolor en cólico en el período PO y la N-butilescopolamina y la dipirona sódica, por sus propiedades anti-espasmódicas y analgésicas, asociadas a las propiedades antiinflamatorias del cetoprofeno, pueden ser opción para la prevención y tratamiento del dolor. No existen, en la literatura, trabajos que comprueben la eficiencia de la N-butilescopolamina y de la dipirona sódica en el tratamiento del dolor PO de laqueadura laparoscópica. El objetivo de ésta fue estudiar la eficacia de la N-butilescopolamina y de la dipirona sódica asociadas al cetoprofeno, en la prevención del dolor PO en pacientes sometidas a la LL, con dos técnicas diferentes - diatermia y pinzamiento con anillo. MÉTODO: Participaron del estudio 50 pacientes, estado físico ASA I y II, con edad entre 23 y 47 años. Las pacientes fueron distribuidas eventualmente en dos grupos: G1 - oclusión de las trompas uterinas con anillos, G2 - oclusión de las trompas uterinas con diatermia. Todas las pacientes recibieron N-butilescopolamina (20 mg y dipirona sódica (2500 mg y cetoprofeno (100 mg, por vía venosa, inmediatamente antes de la inducción de la anestesia. El dolor fue evaluado por el criterio de escala numérica verbal, variando de 0 a 10, siendo 0 ausencia de dolor y 10 el máximo de dolor, a cada 10 minutos en la primera hora, en la sala de recuperación pos-anestésica (SRPA y en la 1ª, 2ª, 3ª y 4ª horas después del alta de la

    9. 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

    10. Electrical transport through a metal-molecule-metal junction

      International Nuclear Information System (INIS)

      Kergueris, Ch.

      1998-01-01

      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 kinds of molecules were adsorbed on the two facing gold electrodes, dodecane-thiol (DT) and bis-thiol-ter-thiophene (α,ω 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 α,ω 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-α,ω 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)

    11. 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.

    12. Method for producing metal oxide nanoparticles

      Science.gov (United States)

      Phillips, Jonathan [Santa Fe, NM; Mendoza, Daniel [Santa Fe, NM; Chen, Chun-Ku [Albuquerque, NM

      2008-04-15

      Method for producing metal oxide nanoparticles. The method includes generating an aerosol of solid metallic microparticles, generating 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 into metal vapor. The metal vapor is directed away from the hot zone and into the cooler plasma afterglow where it oxidizes, cools and condenses to form solid metal oxide nanoparticles.

    13. Comparison of metal ion concentrations and implant survival after total hip arthroplasty with metal-on-metal versus metal-on-polyethylene articulations

      OpenAIRE

      Dahlstrand, Henrik; Stark, André; Wick, Marius C; Anissian, Lucas; Hailer, Nils P; Weiss, Rüdiger J

      2017-01-01

      Background and purpose Large metal-on-metal (MoM) articulations are associated with metal wear and corrosion, leading to increased metal ion concentrations and unacceptable revision rates. There are few comparative studies of 28-mm MoM articulations with conventional metal-on-polyethylene (MoP) couplings. We present a long-term follow-up of a randomized controlled trial comparing MoM versus MoP 28-mm articulations, focused on metal ions and implant survival. Patients and methods 85 patients w...

    14. 19 CFR 19.22 - Withdrawal of metal refined in part from imported crude metal and in part from crude metal...

      Science.gov (United States)

      2010-04-01

      ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Withdrawal of metal refined in part from imported crude metal and in part from crude metal produced from imported materials. 19.22 Section 19.22 Customs... § 19.22 Withdrawal of metal refined in part from imported crude metal and in part from crude metal...

    15. Heavy metals in Antarctic organisms

      Energy Technology Data Exchange (ETDEWEB)

      Moreno, J.E.A. de; Moreno, V.J. [Universidad Nacional de Mar del Plata (Argentina); Gerpe, M.S.; Vodopivez, C. [Instituto Antartico Argentino, Buenos Aires (Argentina)

      1997-02-01

      To evaluate levels of essential (zinc and copper) and non-essential (mercury and cadmium) heavy metals, 34 species of organisms from different areas close to the Antarctic Peninsula were analysed. These included algae, filter-feeders, omnivorous invertebrates and vertebrates. Mercury was not detected, while cadmium was found in the majority of organisms analysed (detection limit was 0.05 ppm for both metals). The highest cadmium concentration was observed in the starfish Odontaster validus. Anthozoans, sipunculids and nudibranchs showed maximum levels of zinc, while the highest copper level was found in the gastropod Trophon brevispira. Mercury and cadmium levels in fishes were below the detection limit. Concentrations of essential and non-essential metals in birds were highest in liver followed by muscle and eggs. Cadmium and mercury levels in muscle of southern elephant seals were above the detection limit, whereas in Antarctic fur seals they were below it. The objective of the study was to gather baseline information for metals in Antarctic Ocean biota that may be needed to detect, measure and monitor future environmental changes. 46 refs., 7 figs., 8 tabs.

    16. The Danish fabricated metal industry:

      DEFF Research Database (Denmark)

      Hansen, Teis

      2010-01-01

      . This is less the case for low-tech industries, but their economic importance continues to be large, however. It is thus interesting to analyse how they manage to remain competitive. The analysis focuses on a case study of the fabricated metal industry by identifying the innovation strategies followed by firms...

    17. Metals near a magnetic instability

      Indian Academy of Sciences (India)

      Abstract. Zero-temperature magnetic phase transitions exhibit an abundance of nearly critical magnetic fluctuations that allow to probe the traditional concepts of the metallic state. For the proto- typical heavy-fermion compound, CeCu6−xAux , a breakdown of the Fermi-liquid properties may be tuned by Au concentration, ...

    18. Plastic Deformation of Metal Surfaces

      DEFF Research Database (Denmark)

      Hansen, Niels; Zhang, Xiaodan; Huang, Xiaoxu

      2013-01-01

      Plastic deformation of metal surfaces by sliding and abrasion between moving parts can be detrimental. However, when the plastic deformation is controlled for example by applying different peening techniques hard surfaces can be produced which can increase the fracture resistance and fatigue life...

    19. Lightweight, Wearable, Metal Rubber Sensor

      Science.gov (United States)

      Hill, Andrea

      2015-01-01

      For autonomous health monitoring. NanoSonic, Inc., has developed comfortable garments with multiple integrated sensors designed to monitor astronaut health throughout long-duration space missions. The combined high electrical conductivity, low mechanical modulus, and environmental robustness of the sensors make them an effective, lightweight, and comfortable alternative to conventional use of metal wiring and cabling.

    20. 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...

    1. 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.

    2. 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...

    3. CELLULAR COMPARTMENTALIZATION AND HEAVY METAL ...

      African Journals Online (AJOL)

      CELLULAR COMPARTMENTALIZATION AND HEAVY METAL LOAD IN THE MOSS. Barbula lambarenensis AROUND A MEGA CEMENT FACTORY IN SOUTHWEST NIGERIA. *. Ogunkunle, C. O. and Fatoba, P. O.. Department of Plant Biology, University of Ilorin .... the free transport of Zn across the cell wall as it.

    4. Metals Separation by Liquid Extraction.

      Science.gov (United States)

      Malmary, G.; And Others

      1984-01-01

      As part of a project focusing on techniques in industrial chemistry, students carry out experiments on separating copper from cobalt in chloride-containing aqueous solution by liquid extraction with triisoctylamine solvent and search the literature on the separation process of these metals. These experiments and the literature research are…

    5. 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...

    6. 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.)

    7. 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 mu...

    8. 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.

    9. 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)

    10. 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)

    11. Transition Metal Complexes and Catalysis

      Indian Academy of Sciences (India)

      Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 9. Transition Metal Complexes and Catalysis. Balaji R Jagirdar. General Article Volume 4 Issue 9 ... Author Affiliations. Balaji R Jagirdar1. Department of Inorganic & Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India.

    12. 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

    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. Metal Casting--Industry of the Future

      Energy Technology Data Exchange (ETDEWEB)

      NONE

      2001-01-23

      This 8-page brochure describes the Office of Industrial Technologies Metal Casting Industry of The Future; a partnership between the Department of Energy and the metal casting industry established to increase industrial energy and cost efficiency.

    16. Metals: In Sickness and in Health

      Science.gov (United States)

      ... Posted February 1, 2012 We're not quite Iron Man, but metals are intricately entwined with our bodies. They make vital functions like respiration, circulation and reproduction possible. Metals like iron (Fe), zinc (Zn) and copper (Cu) are essential ...

    17. Bandstructure calculations for metal hydrogen systems

      International Nuclear Information System (INIS)

      Switendick, A.C.

      1979-01-01

      The factors contributing to hydride stability are discussed for a variety of metal hydride systems. The formation of a low-lying hydrogen associated state is a common feature. A significant transition metal character is also found in these states

    18. Joining porous components to solid metal structures

      Science.gov (United States)

      Fortini, A.; Tulisiak, G.

      1972-01-01

      Process for joining porous metal material to solid metal structure without cracking or blockage of porous component is described. Procedures of electron beam welding and electroforming are discussed. Illustration of microstructure resulting from process is included.

    19. Strategic surfaces in sheet metal forming

      DEFF Research Database (Denmark)

      Olsson, David Dam; Andreasen, Jan Lasson; Bay, Niels

      Out-line: Introduction to tribology in sheet metal forming Developed strategic surfaces Tribological testing of strategic surfaces Conclusion......Out-line: Introduction to tribology in sheet metal forming Developed strategic surfaces Tribological testing of strategic surfaces Conclusion...

    20. 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

    1. Safety consideration when handling metal powders

      CSIR Research Space (South Africa)

      Benson, JM

      2012-03-01

      Full Text Available Metal powder compaction offers unique advantages in the manufacture of net-shape components using techniques such as laser sintering, conventional press and sintering, metal injection moulding, direct rolling, direct forging, and hot isostatic...

    2. Heavy metals in Mindhola river estuary, India

      Digital Repository Service at National Institute of Oceanography (India)

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

      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...

    3. Metal Ions Analysis with Capillary Zone Electrophoresis.

      Science.gov (United States)

      Malik, Ashok Kumar; Aulakh, Jatinder Singh; Kaur, Varinder

      2016-01-01

      Capillary electrophoresis has recently attracted considerable attention as a promising analytical technique for metal ion separations. Significant advances that open new application areas for capillary electrophoresis in the analysis of metal species occurred based on various auxiliary separation principles. These are mainly due to complexation, ion pairing, solvation, and micellization interactions between metal analytes and electrolyte additives, which alter the separation selectivity in a broad range. Likewise, many separation studies for metal ions have been concentrated on the use of preelectrophoresis derivatization methodology. Approaches suitable for manipulation of selectivity for different metal species including metal cations, metal complexes, metal oxoanions, and organometallic compounds, are discussed, with special attention paid to the related electrophoretic system variables using illustrative examples.

    4. 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.

    5. 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.

    6. 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...

    7. 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.

    8. 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...

    9. 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).

    10. Metal ion adsorption characteristics of tea leaves

      OpenAIRE

      Takao, Hiromitsu; Kawahigashi, Tatsuo

      2016-01-01

      [Abstract] For effective use of tea leaves, this study experimentally evaluated metal ion adsorption by tea leaves. The experiment described herein was conducted by measuring the ionic solution at a constant density using a fluorescence X-ray device. The metallic ion concentration in the solution and the fluorescence X-ray output intensity showed good correlation. Tea leaves were put into solution adjusted with density of an already-known metallic ion. Then the decrease of the metal ion was m...

    11. 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)

    12. Bi-metallic nanoparticles as cathode electrocatalysts

      Energy Technology Data Exchange (ETDEWEB)

      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.

    13. Albumin as marker for susceptibility to metal ions in metal-on-metal hip prosthesis patients.

      Science.gov (United States)

      Facchin, F; Catalani, S; Bianconi, E; Pasquale, D De; Stea, S; Toni, A; Canaider, S; Beraudi, A

      2017-04-01

      Metal-on-metal (MoM) hip prostheses are known to release chromium and cobalt (Co), which negatively affect the health status, leading to prosthesis explant. Albumin (ALB) is the main serum protein-binding divalent transition metals. Its binding capacity can be affected by gene mutations or modification of the protein N-terminal region, giving the ischaemia-modified albumin (IMA). This study evaluated ALB, at gene and protein level, as marker of individual susceptibility to Co in MoM patients, to understand whether it could be responsible for the different management of this ion. Co was measured in whole blood, serum and urine of 40 MoM patients. A mutational screening of ALB was performed to detect links between mutations and metal binding. Finally, serum concentration of total ALB and IMA were measured. Serum total ALB concentration was in the normal range for all patients. None of the subjects presented mutations in the investigated gene. Whole blood, serum and urine Co did not correlate with serum total ALB or IMA, although IMA was above the normal limit in most subjects. The individual susceptibility is very important for patients' health status. Despite the limited results of this study, we provide indications on possible future investigations on the toxicological response to Co.

    14. 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

    15. Liquid-metal embrittlement of refractory metals by molten plutonium

      International Nuclear Information System (INIS)

      Lesuer, D.R.; Bergin, J.B.; McInturff, S.A.; Kuhn, B.A.

      1980-07-01

      Embrittlement by molten plutonium of the refractory metals and alloys W-25 wt % Re, tantalum, molybdenum, and Ta-10 wt % W was studied. At 900 0 C and a strain rate of 10 -4 s -1 , the materials tested may be ranked in order of decreasing susceptibility to liquid-plutonium embrittlement as follows: molybdenum, W-25 wt % Re, Ta-10 wt % W, and tantalum. These materials exhibited a wide range in susceptibility. Embrittlement was found to exhibit a high degree of temperature and strain-rate dependence, and we present arguments that strongly support a stress-assisted, intergranular, liquid-metal corrosion mechanism. We also believe microstructure plays a key role in the extent of embrittlement. In the case of W-25 wt % Re, we have determined that a dealloying corrosion takes place in which rhenium is selectively withdrawn from the alloy

    16. Super high conductivity effect in metal-polymer-metal structures

      Science.gov (United States)

      Ionov, Alexander N.; Zakrevskii, V. A.; Svetlichny, V. M.; Rentzsch, R.

      2003-06-01

      We have observed that films of a polyimide precursor of poly[4,4'-bis(4"-N-phenoxy)diphenyl-sulfone] amid acid of 1,3-bis(3',4-dicarboxyphenoxy) benzene which is called type (1) polymer- or co-poly[4,4'-bis(4"-N-phenoxy)diphenyl-sulfone-α,ω-bis(η-amino propyl)oligodimethylsiloxane]imide of 1,3-bis(3',4-dicarboxyphenoxy)benzene type (2) polymer, placed between two metallic electrodes become highly conducting in a relatively small electric field (E<1 V/cm). If the metallic electrodes (Sn, Nb) in sandwich structures were in the superconducting state an effective resistance of zero was recorded. A typical current-voltage characteristic of an S-P-S structure looks like a Josephson type. We hve experimentally shown that for a S-P-S structure, a point contact between the superconductor and the polymer film plays the role of a weak link.

    17. 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.

    18. Local Oxidation Nanolithography on Metallic Transition Metal Dichalcogenides Surfaces

      Directory of Open Access Journals (Sweden)

      Elena Pinilla-Cienfuegos

      2016-09-01

      Full Text Available The integration of atomically-thin layers of two dimensional (2D materials in nanodevices demands for precise techniques at the nanoscale permitting their local modification, structuration or resettlement. Here, we present the use of Local Oxidation Nanolithography (LON performed with an Atomic Force Microscope (AFM for the patterning of nanometric motifs on different metallic Transition Metal Dichalcogenides (TMDCs. We show the results of a systematic study of the parameters that affect the LON process as well as the use of two different modes of lithographic operation: dynamic and static. The application of this kind of lithography in different types of TMDCs demonstrates the versatility of the LON for the creation of accurate and reproducible nanopatterns in exfoliated 2D-crystals and reveals the influence of the chemical composition and crystalline structure of the systems on the morphology of the resultant oxide motifs.

    19. 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

    20. METHOD OF PRODUCING DENSE CONSOLIDATED METALLIC REGULUS

      Science.gov (United States)

      Magel, T.T.

      1959-08-11

      A methcd is presented for reducing dense metal compositions while simultaneously separating impurities from the reduced dense metal and casting the reduced parified dense metal, such as uranium, into well consolidated metal ingots. The reduction is accomplished by heating the dense metallic salt in the presence of a reducing agent, such as an alkali metal or alkaline earth metal in a bomb type reacting chamber, while applying centrifugal force on the reacting materials. Separation of the metal from the impurities is accomplished essentially by the incorporation of a constricted passageway at the vertex of a conical reacting chamber which is in direct communication with a collecting chamber. When a centrifugal force is applled to the molten metal and slag from the reduction in a direction collinear with the axis of the constricted passage, the dense molten metal is forced therethrough while the less dense slag is retained within the reaction chamber, resulting in a simultaneous separation of the reduced molten metal from the slag and a compacting of the reduced metal in a homogeneous mass.

    1. Different interactions of fungi with toxic metals

      OpenAIRE

      Fanelli, Corrado; Fabbri, Anna Adele; Pilo, Giuseppina; Luongo, Laura; Corazza, Luciana; Melis, Pietro

      1994-01-01

      Many papers have reported the uptake and translocation of toxic metals and radionuclides to fruit bodies of edible fungi and also to mycelia biomass. Our aim is to study how to reduce the metal phytotoxicity by mychorrizal fungi pointing at land reclamation and at the detoxification of metal/radionuclides-containing industrial effluents.

    2. 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.

    3. 77 FR 20649 - Silicon Metal From China

      Science.gov (United States)

      2012-04-05

      ... COMMISSION Silicon Metal From China Determination On the basis of the record \\1\\ developed in the subject... order on silicon metal from China would be likely to lead to continuation or recurrence of material... Publication 4312 (March 2012), entitled Silicon Metal from China: Investigation No. 731-TA-472 (Third Review...

    4. 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.

    5. 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.

    6. Refractory metals extraction, processing and applications

      International Nuclear Information System (INIS)

      Liddell, K.C.; Sadoway, D.R.; Bautista, R.G.

      1990-01-01

      This book covers the following topics regarding refractory metals: process flowsheet development; high temperature extraction processes; chemical and thermal processing; electrolytic processing; preparation of ceramic precursors and application of aqueous chemistry to metal recovery; processing and properties. Some of the metals covered include: hafnium, vanadium, niobium, zirconium, and tantalum

    7. Structural sound absorption in liquid metals

      International Nuclear Information System (INIS)

      Niyazov, S.

      1993-01-01

      Present article is devoted to structural sound absorption in liquid metals. The study of sound absorption in liquid metals shown that in all studied objects the structural absorption of sound was observed. The mechanism of structural relaxation in molten metal was revealed.

    8. 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...

    9. SYNTHESIS AND CHARACTERIZATION OF TRANSITION METAL ...

      African Journals Online (AJOL)

      a

      The metal complexes separated out were filtered through the sintered glass crucible ... All the metal complexes (Table 2) are colored, stable to air at room temperature ... Table 2. Physical characteristics and conductivity data of metal complexes and ligands. Ligand/complex. Color. Melting/decomposition temperature, 0C.

    10. 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

    11. 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....

    12. 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

    13. 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....

    14. Critical loads of heavy metals for soils

      NARCIS (Netherlands)

      Vries, de W.; Groenenberg, J.E.; Lofts, S.; Tipping, E.; Posch, M.

      2012-01-01

      To enable a precautionary risk assessment for future inputs of metals, steady-state methods have been developed to assess critical loads of metals avoiding long-term risks to food quality and eco-toxicological effects on organisms in soils and surface waters. A critical load for metals equals the

    15. Liquid metal engineering and technology. Volume 3

      International Nuclear Information System (INIS)

      1988-01-01

      These proceedings of the fourth international conference on liquid metal engineering and technology, volume 3, are divided into 3 sections bearing on: - materials and structures in liquid metal environment (16 conferences) - impurity monitoring and removal (37 conferences) - operating experience with liquid metals (15 conferences) [fr

    16. Metal-support bonds in supported metal catalysts

      Energy Technology Data Exchange (ETDEWEB)

      Gates, B.C.

      1990-01-01

      This research project, now in its third year, is an investigation of the synthesis, structure, and bonding of a family of metal complexes, clusters, and particles on the surfaces of high-area metal oxide supports. The focus is the structure of the metal-support interface. Surface species have been prepared by synthetic organometallic chemistry on the support surfaces. The organometallic precursors are complexes of W, Re, Os, Ir, and Pt, including W(CO){sub 6}, HRe(CO){sub 5}, Re{sub 2}(CO){sub 10}, H{sub 3}Re{sub 3}(CO){sub 12}, H{sub 2}Os(CO){sub 4}, Ir({eta}{sup 3}-C{sub 3}H{sub 5}){sub 3}, and Pt({eta}{sup 3}-C{sub 3}H{sub 5}){sub 2}. The supports are primarily MgO and {gamma}-Al{sub 2}O{sub 3}. The surface species have been characterized by infrared and EXAFS spectroscopies, among other techniques. 7 refs., 5 figs., 4 tabs.

    17. Metals and Neuronal Metal Binding Proteins Implicated in Alzheimer's Disease

      Science.gov (United States)

      2016-01-01

      Alzheimer's disease (AD) is the most prevalent age-related dementia affecting millions of people worldwide. Its main pathological hallmark feature is the formation of insoluble protein deposits of amyloid-β and hyperphosphorylated tau protein into extracellular plaques and intracellular neurofibrillary tangles, respectively. Many of the mechanistic details of this process remain unknown, but a well-established consequence of protein aggregation is synapse dysfunction and neuronal loss in the AD brain. Different pathways including mitochondrial dysfunction, oxidative stress, inflammation, and metal metabolism have been suggested to be implicated in this process. In particular, a body of evidence suggests that neuronal metal ions such as copper, zinc, and iron play important roles in brain function in health and disease states and altered homeostasis and distribution as a common feature across different neurodegenerative diseases and aging. In this focused review, we overview neuronal proteins that are involved in AD and whose metal binding properties may underlie important biochemical and regulatory processes occurring in the brain during the AD pathophysiological process. PMID:26881049

    18. 21 CFR 888.3210 - Finger joint metal/metal constrained cemented prosthesis.

      Science.gov (United States)

      2010-04-01

      ... prosthesis. 888.3210 Section 888.3210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/metal constrained cemented prosthesis. (a) Identification. A finger joint metal/metal constrained cemented prosthesis is a device intended to be implanted to replace a metacarpophalangeal (finger) joint...

    19. 21 CFR 888.3550 - Knee joint patellofemorotibial polymer/metal/metal constrained cemented prosthesis.

      Science.gov (United States)

      2010-04-01

      ... constrained cemented prosthesis. 888.3550 Section 888.3550 Food and Drugs FOOD AND DRUG ADMINISTRATION... § 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...

    20. 21 CFR 888.3200 - Finger joint metal/metal constrained uncemented prosthesis.

      Science.gov (United States)

      2010-04-01

      ... prosthesis. 888.3200 Section 888.3200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal/metal constrained uncemented prosthesis. (a) Identification. A finger joint metal/metal constrained uncemented prosthesis is a device intended to be implanted to replace a metacarpophalangeal or...

    1. Asymptomatic pseudotumours after metal-on-metal hip resurfacing show little change within one year

      NARCIS (Netherlands)

      van der Weegen, W.; Brakel, K.; Horn, R. J.; Hoekstra, H. J.; Sijbesma, T.; Pilot, P.; Nelissen, R. G. H. H.

      2013-01-01

      The aim of this study was to establish the natural course of unrevised asymptomatic pseudotumours after metal-on-metal (MoM) hip resurfacing during a six- to 12-month follow-up period. We used repeated metal artefact reduction sequence (MARS)-magnetic resonance imaging (MRI), serum metal ion

    2. Systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions

      Science.gov (United States)

      Cooks, Robert Graham; Li, Anyin; Luo, Qingjie

      2017-08-01

      The invention generally relates to systems and methods for producing metal clusters; functionalized surfaces; and droplets including solvated metal ions. In certain aspects, the invention provides methods that involve providing a metal and a solvent. The methods additionally involve applying voltage to the solvated metal to thereby produce solvent droplets including ions of the metal containing compound, and directing the solvent droplets including the metal ions to a target. In certain embodiments, once at the target, the metal ions can react directly or catalyze reactions.

    3. Breast milk metal ion levels in a young and active patient with a metal-on-metal hip prosthesis.

      Science.gov (United States)

      Nelis, Raymond; de Waal Malefijt, Jan; Gosens, Taco

      2013-01-01

      Metal-on-metal resurfacing arthroplasty of the hip has been used increasingly over the last 10 years in younger active patients. The dissolution of the metal wear particles results in measurable increases in cobalt and chromium ions in the serum and urine of patients with a metal-on-metal bearing. We measured the cobalt, chromium, and molybdenum ion levels in urine; serum; and breast milk in a young and active patient with a metal-on-metal hip prosthesis after a pathologic fracture of the femoral neck. Metal-on-metal hip prosthesis leads to increasing levels of molybdenum in breast milk in the short-term follow-up. There are no increasing levels of chromium and cobalt ions in breast milk. Besides the already known elevated concentrations in serum of chromium and cobalt after implantation of a metal-on-metal hip prosthesis, we found no increasing levels of chromium and cobalt in urine. Copyright © 2013 Elsevier Inc. All rights reserved.

    4. Metal Hydrides for Rechargeable Batteries

      Energy Technology Data Exchange (ETDEWEB)

      Valoeen, Lars Ole

      2000-03-01

      Rechargeable battery systems are paramount in the power supply of modern electronic and electromechanical equipment. For the time being, the most promising secondary battery systems for the future are the lithium-ion and the nickel metal hydride (NiMH) batteries. In this thesis, metal hydrides and their properties are described with the aim of characterizing and improving those. The thesis has a special focus on the AB{sub 5} type hydrogen storage alloys, where A is a rare earth metal like lanthanum, or more commonly misch metal, which is a mixture of rare earth metals, mainly lanthanum, cerium, neodymium and praseodymium. B is a transition metal, mainly nickel, commonly with additions of aluminium, cobalt, and manganese. The misch metal composition was found to be very important for the geometry of the unit cell in AB{sub 5} type alloys, and consequently the equilibrium pressure of hydrogen in these types of alloys. The A site substitution of lanthanum by misch metal did not decrease the surface catalytic properties of AB{sub 5} type alloys. B-site substitution of nickel with other transition elements, however, substantially reduced the catalytic activity of the alloy. If the internal pressure within the electrochemical test cell was increased using inert argon gas, a considerable increase in the high rate charge/discharge performance of LaNi{sub 5} was observed. An increased internal pressure would enable the utilisation of alloys with a high hydrogen equivalent pressure in batteries. Such alloys often have favourable kinetics and high hydrogen diffusion rates and thus have a potential for improving the high current discharge rates in metal hydride batteries. The kinetic properties of metal hydride electrodes were found to improve throughout their lifetime. The activation properties were found highly dependent on the charge/discharge current. Fewer charge/discharge cycles were needed to activate the electrodes if a small current was used instead of a higher

    5. Nanotoxicity: the toxicity research progress of metal and metal-containing nanoparticles.

      Science.gov (United States)

      Ding, Lingling; Liu, Zhidong; Aggrey, Mike Okweesi; Li, Chunhua; Chen, Jing; Tong, Ling

      2015-01-01

      Along with the exuberant development of nanotechnology, a large number of nanoformulations or non materials are successfully applied in the clinics, biomedicine, cosmetics and industry. Despite some unique advantages of nanoformulations, there exist potentially worrying toxic effects, particularly those related to metal and metal-containing nanoparticles (NPs). Although various researches have been conducted to assess the metallic and metal-containing nanoparticles toxic effects, only little is known about the toxicity expressive types and evaluation, reasons and mechanisms, influencing factors and research methods of metal and metal-containing nanotoxicity. Therefore, it is of importance to acquire a better understanding of metal and metal-containing nanoparticles toxicity for medical application. This review presents a summary on the metal and metal-containing nanoparticles toxicity research progress consulting relevant literature.

    6. Separating and recycling metals from mixed metallic particles of crushed electronic wastes by vacuum metallurgy.

      Science.gov (United States)

      Zhan, Lu; Xu, Zhenming

      2009-09-15

      During the treatment of electronic wastes, a crushing process is usually used to strip metals from various base plates. Several methods have been applied to separate metals from nonmetals. However, mixed metallic particles obtained from these processes are still a mixture of various metals, including some toxic heavy metals such as lead and cadmium. With emphasis on recovering copper and other precious metals, there have hitherto been no satisfactory methods to recover these toxic metals. In this paper, the criterion of separating metals from mixed metallic particles by vacuum metallurgy is built. The results show that the metals with high vapor pressure have been almost recovered completely, leading to a considerable reduction of environmental pollution. In addition, the purity of copper in mixed particles has been improved from about 80 wt % to over 98 wt %.

    7. Noble metal alloys for metal-ceramic restorations.

      Science.gov (United States)

      Anusavice, K J

      1985-10-01

      A review of the comparative characteristics and properties of noble metal alloys used for metal-ceramic restorations has been presented. Selection of an alloy for one's practice should be based on long-term clinical data, physical properties, esthetic potential, and laboratory data on metal-ceramic bond strength and thermal compatibility with commercial dental porcelains. Although gold-based alloys, such as the Au-Pt-Pd, Au-Pd-Ag, and Au-Pd classes, may appear to be costly compared with the palladium-based alloys, they have clearly established their clinical integrity and acceptability over an extended period of time. Other than the relatively low sag resistance of the high gold-low silver content alloys and the potential thermal incompatibility with some commercial porcelain products, few clinical failures have been observed. The palladium-based alloys are less costly than the gold-based alloys. Palladium-silver alloys require extra precautions to minimize porcelain discoloration. Palladium-copper and palladium-cobalt alloys may also cause porcelain discoloration, as copper and cobalt are used as colorants in glasses. The palladium-cobalt alloys are least susceptible to high-temperature creep compared with all classes of noble metals. Nevertheless, insufficient clinical data exist to advocate the general use of the palladium-copper and palladium-cobalt alloys at the present time. One should base the selection and use of these alloys in part on their ability to meet the requirements of the ADA Acceptance Program. A list of acceptable or provisionally acceptable alloys is available from the American Dental Association and is published annually in the Journal of the American Dental Association. Dentists have the legal and ethical responsibility for selection of alloys used for cast restorations. This responsibility should not be delegated to the dental laboratory technician. It is advisable to discuss the criteria for selection of an alloy with the technician and the

    8. Metals used in maxillofacial surgery.

      Science.gov (United States)

      Pacifici, L; DE Angelis, F; Orefici, A; Cielo, A

      2016-01-01

      The goal of maxillofacial surgery is to restore the shape and functionality of maxillofacial region. In the past years, there has been a tremendous progress in this field because of significant advances in biotechnology that provided innovative biomaterials to efficiently reconstruct the maxillofacial injured region. By using appropriate selection of the implant biomaterial, it is possible to reconstruct the native tissue, both in form and function. The ideal biomaterial should mimic native tissues regarding density, strength, and modulus of elasticity. Autografts are currently the gold standard for replacement of missing tissues, but synthetic biomaterials have been widely used because they eliminate the discomfort to take the replacement tissue from the donor site. Among synthetic biomaterials, different metals may be utilized to efficiently reconstruct the maxillofacial injured region. This article makes an effort to summarize the most important metals in use in maxillofacial surgery, and point out advantages and disadvantage of each type.

    9. Noble-Metal Chalcogenide Nanotubes

      Directory of Open Access Journals (Sweden)

      Nourdine Zibouche

      2014-10-01

      Full Text Available We explore the stability and the electronic properties of hypothetical noble-metal chalcogenide nanotubes PtS2, PtSe2, PdS2 and PdSe2 by means of density functional theory calculations. Our findings show that the strain energy decreases inverse quadratically with the tube diameter, as is typical for other nanotubes. Moreover, the strain energy is independent of the tube chirality and converges towards the same value for large diameters. The band-structure calculations show that all noble-metal chalcogenide nanotubes are indirect band gap semiconductors. The corresponding band gaps increase with the nanotube diameter rapidly approaching the respective pristine 2D monolayer limit.

    10. Relaxation Pathways in Metallic Glasses

      Science.gov (United States)

      Gallino, Isabella; Busch, Ralf

      2017-11-01

      At temperatures below the glass transition temperature, physical properties of metallic glasses, such as density, viscosity, electrical resistivity or enthalpy, slowly evolve with time. This is the process of physical aging that occurs among all types of glasses and leads to structural changes at the microscopic level. Even though the relaxation pathways are ruled by thermodynamics as the glass attempts to re-attain thermodynamic equilibrium, they are steered by sluggish kinetics at the microscopic level. Understanding the structural and dynamic pathways of the relaxing glassy state is still one of the grand challenges in materials physics. We review some of the recent experimental advances made in understanding the nature of the relaxation phenomenon in metallic glasses and its implications to the macroscopic and microscopic properties changes of the relaxing glass.

    11. Amorphous metal based nanoelectromechanical switch

      KAUST Repository

      Mayet, Abdulilah M.

      2013-04-01

      Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

    12. Mechanical pumps for liquid metals

      International Nuclear Information System (INIS)

      Baumier, J.; Gollion, H.J.

      1964-01-01

      The pumping of liquid metals by centrifugal pumps poses two principal problems. These are hermetic sealing of the rotating shaft and, its guidance where immersed in liquid metal. The solutions to the problems used on 13 experimental pumps are given here. The resolution of the guidance problem consists in the majority of cases in the utilisation of hydrostatic bearings. Accordingly, a theoretical study was instituted for the first time to calculate the bearings of the earlier pumps. After this, an experimental study was carried out, to check the theory by water tests. A relation for bearing calculation of pumps with diffusers is proposed. Finally the influence of the bearing elasticity on the shafts critical speed is studied. (authors) [fr

    13. Metal extrusion using hydrostatic pressures

      International Nuclear Information System (INIS)

      Sauve, Ch.

      1965-01-01

      The main problems connected with the deformation of metals due to extrusion are described. A method is put forward for calculating the rational rate of percentage deformation in the case of bar extrusion using a cylindrical container; reference is made to previous work on extrusion using a hydrostatic pressure with or without back-pressure. An extrusion process is described using hydrostatic pressure, without back-pressure, and using the lubricant for transmitting the thrust. This process has been used for eight years by the C.E.A. for the extrusion of a very wide range of metals, from beryllium to uranium and including steels; it leads to excellent surface textures. A very fine crystallization can be obtained on extruded products when the rate of extrusion is very low. There appears to be nothing against the use of high extrusion rates using this method. (author) [fr

    14. Composite pipe to metal joint

      Science.gov (United States)

      Leslie, James C.; Leslie, II, James C.; Heard, James; Truong, Liem V.; Josephson, Marvin

      2017-06-27

      A method for making a metal to composite tube joint including selecting an elongated interior fitting constructed with an exterior barrel, reduced in exterior diameter to form a distally facing annular shoulder and then projecting still further distally to form an interior sleeve having a radially outwardly facing bonding surface. Selecting an elongated metal outer sleeve formed proximally with a collar constructed for receipt over the barrel and increased in interior diameter and projecting distally to form an exterior sleeve having a radially inwardly facing bonding surface cooperating with the first bonding surface to form an annulus receiving an extremity of a composite tube and a bond bonding the extremity of the tube to the bonding surfaces.

    15. Synchrotron tomography on metallic foams

      International Nuclear Information System (INIS)

      Haibel, A.; Banhart, J.

      2003-01-01

      Metallic foams are a class of materials with unique properties. In contrast to most aqueous foams which are stable due to surface active agents, the liquid state of metallic foams can be stabilized by admixing small non-soluble particles. We present the results of our investigations on such materials consisting three different components: an aluminium alloy, silicon carbide particles for foam stabilization, and titanium hydride acting as blowing agent. By means of synchrotron-tomography we visualized the three dimensional distribution of the silicon carbide and the titanium hydride particles in the unfoamed cast solid precursor, in the fully foamed liquid state, and in the solidified final state of the foam. We analyzed the silicon carbide formation in these three foaming stages and its influence of the pore stability

    16. Fundamentals of metal oxide catalysis

      Science.gov (United States)

      Nair, Hari

      The properties of metal oxide catalysts and hence, catalytic activity are highly dependent on the composition and structure of these oxides. This dissertation has 3 parts -- all directed towards understanding relationships between structure, composition and activity in metal oxide catalysts. The first part of this dissertation focuses on supported metal oxide catalysts of tungsten, vanadium and molybdenum. Mechanisms are proposed for ethanol oxidative dehydrogenation which is used to probe the acidity and reducibility of these oxide catalysts. These studies are then used to develop a novel method to quantify active redox sites and determine the nature of the active site on these catalysts -- our results show that the intrinsic redox turn-over frequency is independent of the nature of the metal oxide and its loading and that the actual rate obtained over an oxide is only a function of the number of removable oxygen atoms linking the metal to the support. The extension of Ultraviolet-visible Diffuse Reflectance Spectroscopy (UV-vis DRS) to the study of active oxide domains in binary oxide catalysts is demonstrated for distinguishing between interacting and non-interacting domains in binary MoO x-WOx catalysts on alumina. We show also how the rigorous analysis of pre-edge features, absorption white-line intensity and the full width at half maximum of the white-line in X-ray Absorption Spectra provide determinants for metal atom coordination and domain size in supported metal oxide catalysts. The second part of this work looks at effects of structure variations on the activity of polyoxometalate catalysts that are promising for the production of Methacrylic Acid from Isobutane. The use of these catalysts is limited by structural changes that impact their performance -- an "activation" period is required before the catalysts become active for methacrylic acid production and structural changes also lead to degradation of the catalyst, which are also seen during thermal

    17. Fullerenes doped with metal halides

      International Nuclear Information System (INIS)

      Martin, T.P.; Heinebrodt, M.; Naeher, U.; Goehlich, H.; Lange, T.; Schaber, H.

      1993-01-01

      The cage-like structure of fullerenes is a challenge to every experimental to put something inside - to dope the fullerenes. In fact, the research team that first identified C 60 as a football-like molecule quickly succeeded in trapping metal atoms inside and in shrinking the cage around this atom by photofragmentation. In this paper we report the results of ''shrink-wrapping'' the fullerenes around metal halide molecules. Of special interest is the critical size (the minimum number of carbon atoms) that can still enclose the dopant. A rough model for the space available inside a carbon cage gives good agreement with the measured shrinking limits. (author). 8 refs, 6 figs

    18. Inflammatory pseudotumor causing deep vein thrombosis after metal-on-metal hip resurfacing arthroplasty.

      LENUS (Irish Health Repository)

      Memon, Adeel Rasool

      2013-01-01

      Metal-on-metal hip resurfacings have recently been associated with a variety of complications resulting from adverse reaction to metal debris. We report a case of extensive soft tissue necrosis associated with a huge pelvic mass causing extensive deep vein thrombosis of the lower limb secondary to mechanical compression of the iliac vein. This is a rare and unusual cause of deep vein thrombosis after metal-on-metal hip resurfacing arthroplasty.

    19. Recent materials compatibility studies in refractory metal-alkali metal systems for space power applications.

      Science.gov (United States)

      Harrison, R. W.; Hoffman, E. E.; Davies, R. L.

      1972-01-01

      Advanced Rankine and other proposed space power systems utilize refractory metals in contact with both single-phase and two-phase alkali metals at elevated temperatures. A number of recent compatibility experiments are described which emphasize the excellent compatibility of refractory metals with the alkali metals, lithium, sodium, and potassium, under a variety of environmental conditions. The alkali metal compatibilities of tantalum-, columbium-, molybdenum-, and tungsten-base alloys are discussed.

    20. Metal Nanoparticles in Ionic Liquids.

      Science.gov (United States)

      Wegner, Susann; Janiak, Christoph

      2017-08-01

      During the last years ionic liquids (ILs) were increasingly used and investigated as reaction media, hydrogen sources, catalysts, templating agents and stabilizers for the synthesis of (monometallic and bimetallic) metal nanoparticles (M-NPs). Especially ILs with 1,3-dialkyl-imidazolium cations featured prominently in the formation and stabilization of M-NPs. This chapter summarizes studies which focused on the interdependencies of the IL with the metal nanoparticle and tried to elucidate, for example, influences of the IL-cation, -anion and alkyl chain length. Qualitatively, the size of M-NPs was found to increase with the size of the IL-anion. The influence of the size of imidazolium-cation is less clear. The M-NP size was both found to increase and to decrease with increasing chain lengths of the 1,3-dialkyl-imidazolium cation. It is evident from such reports on cation and anion effects of ILs that the interaction between an IL and a (growing) metal nanoparticle is far from understood. Factors like IL-viscosity, hydrogen-bonding capability and the relative ratio of polar and non-polar domains of ILs may also influence the stability of nanoparticles in ionic liquids and an improved understanding of the IL-nanoparticle interaction would be needed for a more rational design of nanomaterials in ILs. Furthermore, thiol-, ether-, carboxylic acid-, amino- and hydroxyl-functionalized ILs add to the complexity by acting also as coordinating capping ligands. In addition imidazolium cations are precursors to N-heterocyclic carbenes, NHCs which form from imidazolium-based ionic liquids by in situ deprotonation at the acidic C2-H ring position as intermediate species during the nanoparticle seeding and growth process or as surface coordinating ligand for the stabilization of the metal nanoparticle.