Experiencias de la instauración de normas relativas al contenido de plomo en aire y el agua, en los Estados Unidos de América Establishing lead in air and water standards in the United States of America

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J Michael Davis

2003-01-01

Full Text Available En los Estados Unidos de América se ha logrado una disminución de la exposición a plomo de la población en general, gracias al establecimiento de diversas normas. En este artículo se destaca parte de los conocimientos adquiridos a través de la experiencia obtenida en este país en materia de plomo, en particular respecto al aire y al agua. Uno de los aspectos fundamentales es la posibilidad de contar con una base científica sólidamente establecida y claramente entendida, a partir de la cual se tomarán las medidas correspondientes. Los efectos secundarios de ciertas normas concernientes al aire ponen de manifiesto de qué manera los esfuerzos orientados a solucionar un problema pueden aportar beneficios en otras áreas, si bien pueden surgir consecuencias no deseadas, debido a la falta de previsión y de evaluación. Asimismo, en este documento se discuten las diferencias entre los enfoques centralizados y los descentralizados para el manejo de la exposición a plomo.Lead regulations and standards have resulted in a lower exposure to lead in the general population of the United States of America. This paper highlights some of the know-how developed through lead-containing experiences, particularly regarding lead content in air and water. The availability of a solid and clear scientific knowledge is central to the success of these policies. Collateral effects of some air-related standards show the extent to which problem-oriented efforts may be beneficial in other areas, inasmuch as they may have untoward consequences if careful planning and evaluation are not considered. Finally, this paper presents a discussion of the differences between centralized and decentralized approaches to lead exposure control.

Acumulación de plomo en hueso y sus efectos en la salud

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Sanín Luz Helena

1998-01-01

Full Text Available Los efectos nocivos del plomo han sido conocidos desde tiempos antiguos por su amplia gama; este metal afecta prácticamente todos los órganos y sistemas del cuerpo humano. Recientemente se han documentado efectos tóxicos crónicos en los sistemas cardiovascular y nervioso, con niveles que antes se consideraban seguros. El sitio primario de almacenamiento de plomo en el organismo es el hueso, pero sólo hasta fechas recientes se ha clarificado la significancia toxicológica de este hecho. En este artículo se analiza el papel del plomo en hueso como fuente de exposición endógena, como biomarcador de exposición crónica y como tejido blanco. Se presentan además los avances recientes para la medición de plomo en hueso mediante los rayos X-fluorescentes (XRF. Finalmente se revisa la importancia, para la salud pública, de estudiar y medir el plomo en hueso en lugares con una historia de exposición crónica como la Ciudad de México y en los ambientes ocupacionales, especialmente como fuente remanente de exposición. Se analiza especialmente el caso de mujeres en edad reproductiva, quienes pueden convertirse en fuentes de exposición para el feto y para el niño amamantado.

Exposición a plomo en trabajadores de fábricas informales de baterías

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Augusto V Ramírez

2008-06-01

Full Text Available Introducción: El problema del trabajo industrial con plomo es universal, sobretodo cuando se trabaja sin criterios de higiene ocupacional. En el Perú la industria minero metalúrgica del plomo mantiene programas de gestión en salud ocupacional de buena calidad, pero no sucede lo mismo en la industria informal del plomo. Objetivos: Investigar el estado de salud de trabajadores de fábricas artesanales e informales de baterías, usando como indicador de exposición nivel de plomo en sangre. Diseño: Estudio de tipo observacional y transversal. Lugar de estudio: Fábricas de baterías del sector informal en el sur del Perú y en el Servicio de Salud Ocupacional Hospital Ilo, Perú. Participantes: Trabajadores de cuatro fábricas de baterías del sector informal. Intervenciones: La información se obtuvo mediante entrevista directa a 41 trabajadores. El estudio fue realizado entre agosto 1999 y enero 2000. Para medir plomo sanguíneo, se utilizó espectrofotometría de absorción atómica con horno de grafito y para hemoglobina, microhematocrito. Se obtuvo datos en porcentajes, promedios, rangos y desviaciones estándar. Se comparó los resultados de niveles de plomo sanguíneo con variables de salud e higiene ocupacional. Principales medidas de los resultados: Asociación entre plomo sanguíneo y síntomas de saturnismo. Resultados: La edad promedio del grupo fue 35 años (rango: 16 a 52, media de tiempo de trabajo, 6,5 años. El promedio de plomo sanguíneo fue 37,7 ug/dL (rango: 13,5 a 72,3, desviación estándar: 15,7, hemoglobina media 11,2 g/dL (rango: 8,9 - 13,2, desviación estándar 1,1. Se halló asociación estadística significativa entre plomo sanguíneo elevado y síntomas de saturnismo (p<0,05, trabajo como soldador-fundidor (p<0,001 y malos hábitos de higiene ocupacional (p<0,05. Conclusiones: La salud del trabajador en este grupo ocupacional se encontró afectada. El valor medio de plomo sanguíneo encontrado fue 37,7 ug/dL y la

Uso de cerámica vidriada como fuente de exposición a plomo en niños indígenas de zonas marginadas de Oaxaca, México

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Martha Ma. Téllez Rojo Solís

2015-05-01

Full Text Available Objetivo. Conocer si el uso de lozo de barro vidriada (LBV se asocia con concentraciones de plomo en sangre en niños de zonas rurales de Oaxaca, México. Material y métodos. Se evaluó el uso de LBV en el hogar como principal fuente de exposición al plomo en 387 niños escolares indígenas de Oaxaca durante mayo de 2001. Resultados. Se encontró una diferencia ajustada de plomo en sangre (PbS (evaluada por Environmental Testing and Consulting [LeadCare] de 3.9μg/ dl (p<0.01 mayor en niños que reportaron usar (82% LBV en el hogar contra los que reportaron no usarlo. Además, 60 y 27% de los niños tuvieron concentraciones de PbS mayores o iguales a 10 y 20µg/dl, respectivamente. Conclusión. La intoxicación por plomo por el uso de LBV podría seguir siendo una preocupación para la salud pública en México

Niveles de plomo sanguíneo en recién nacidos de La Oroya, 2004-2005

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Godofredo Pebe

2008-10-01

Full Text Available Objetivo. Determinar los niveles de plomo en sangre de los recién nacidos (RN de menos de 12 horas de vida, en la ciudad de La Oroya. Material y métodos. Estudio descriptivo, transversal y prospectivo realizado entre junio de 2004 a junio de 2005 de una muestra de recién nacidos (RN de La Oroya, se usó un cuestionario para la madre gestante y se determinó los niveles de plomo en sangre venosa (2 mL utilizando la espectrofotometría por absorción atómica con llama de aire de acetileno. Los valores se expresan en microgramos de plomo por decilitro de sangre (μg/dL. Resultados. Se evaluσ 93 RN; el nivel promedio de plomo en sangre fue de 8,84 ± 0,57 μg/dL. El 75,3% (70/ RN tuvo niveles de plomo en sangre entre 6 a 10 μg/dL, y 24,7% (23 RN tuvo mαs de 10 μg/dL. Los RN de madres que viven en La Oroya Nueva tienen menos niveles de plomo que los que viven en La Oroya Antigua (p=0,002. Conclusiones. Los RN de la ciudad de La Oroya presentan elevados niveles de plomo en sangre, por lo que se requiere iniciar programas de prevención en las madres gestantes para evitar futuros daños a la salud de los recién nacidos.

Efecto del fotoperiodo en la remoción de plomo por Lemna gibba L. (Lemnaceae

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Guadalupe Miranda

2015-08-01

Full Text Available El plomo llega a las aguas provenientes de las industrias de baterías, soldaduras, pinturas, etc. causando daños a los seres vivos, por lo que es necesario promover el desarrollo de tecnologías que ayuden a mejorar la calidad de los efluentes y que al mismo tiempo sean adecuadas al contexto socioeconómico del país. En este trabajo se plantea el uso de una angiosperma acuática, la especieLemna gibbade la familia Lemnaceae que tiene un crecimiento exponencial y su cultivo es fácil en laboratorio. Para absorber el plomo (PbNO32 se prepararon cinco concentraciones, a nivel de bioensayo en el laboratorio y bajo el efecto de dos diferentes condiciones de fotoperiodo (luz continua y 12 h luz/12 h oscuridad durante cuatro días, ya que a partir de este día libera el Pb al medio. Los resultados indican que en las dos concentraciones de Pb más bajas (30 y 50 mgl-1, el fotoperiodo 12/12 es más favorable para su absorción (9405 µgl-1más y 18,895 µgl-1 más respectivamente mientras que en las tres restantes (100, 200 y 300 mgl-1 lo fue la condición de luz continua. (6600 µgl-1, 1949 µgl-1, 5587 µgl-1 más respectivamente. Los conocimientos que se derivan de este estudio, permiten optimizar el uso deL. gibbaen el tratamiento terciario de aguas residuales.

Estudios de bioadsorción de plomo por Saccharomyces cereviceae en soluciones acuosas

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Juan José Pauro Roque

2009-01-01

Full Text Available El ecosistema del lago Titicaca (Puno, Perú y sus tributarios, viene siendo perturbado por metales pesados producto de la actividad minera emergente. Para controlar y reducir la contaminación existen procesos biológicos llevados a cabo por microorganismos como las levaduras (biorremediación. Este trabajo de investigación tiene como objetivos evaluar la capacidad de bioadsorción de plomo mediante  Saccharomyces cereviceae en soluciones acuosas y la influencia de dos niveles de pH durante la bioadsorción. Para esto se ensayaron dos concentraciones de S. cereviceae (cel/mL, las cuales fueron cuantificadas por un hemocitómetro y luego traspasadas a una solución con concentraciones conocidas de plomo (5 y 25 mg/L. Se realizaron lecturas de las concentraciones de plomo a los 5, 60 y 120 minutos. La mayor capacidad de bioadsorción resultó cuando S. cereviceae estaba a una concentración de 5 x 106 cel/mL, y el pH óptimo fue de 5,14. Se concluye que S. cereviceae constituye una buena alternativa para la bioadsorción de plomo, quedando abierta su validación en condiciones de campo en el altiplano peruano.

Lake Chapala, Mexico: lead distribution in water, sediment and bacteria; Escenarios de la distribucion de plomo en agua, sedimentos y bacterias del lago de Chapala, Mexico

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Hansen, Anne M. [Instituto Mexicano de Tecnologia del Agua, Jiutepec, Morelos (Mexico); Villa-Navia, Adriana [Interventor Ambiental de Occidental de Colombia, Inc. (Colombia); Afferden, Manfred van [Instituto Mexicano de Tecnologia del Agua, Jiutepec, Morelos (Mexico)

2006-04-15

To evaluate the distribution of lead in the natural resources of lake Chapala, the adsorption of this metal in bacteria was analyzed and, through published data and the application of a chemical equilibrium model, the risk associated with the consumption of fish and water was estimated. Adsorption experiments of lead in three bacterial strains and simulations of the distribution of lead in the water-sediment-bacteria system indicate that the distribution of lead in the lake depends on variations of water quality such as suspended solids, lead and biomass concentrations. Considering only the lead contained in the bottom sediments, the simulations suggest that concentrations do not exceed the limits nor the criteria for use and protection of water, sediments, and biota. Considering an additional source of lead that locally increases the concentration by a factor of ten, the amount of lead in water and sediments may exceed these limits. The bioaccumulation of lead in lake Chapala was evaluated through calculation of bioconcentration and biomagnification factors, using simulated and published data on lead in fish (Ayla Jay y Ford, 2001). The results indicate that lead may be concentrated 721 and 6,195 times in bacteria and fish, respectively. Furthermore, bioaccumulation of lead in the lake may occur mainly as bioconcentration in fish rather than biomagnification in the food chain. [Spanish] Para evaluar la distribucion de plomo en los recursos naturales en el lago de Chapala se analizo la adsorcion de este metal en bacterias y, mediante datos publicados en la literatura y modelacion numerica, se estimo el riesgo asociado al consumo de peces y agua. Experimentos de adsorcion en tres cepas de bacterias y simulaciones de la distribucion en un sistema agua-sedimentos-bacterias indican que la distribucion del plomo en el lago depende de variaciones en calidad del agua tales como solidos suspendidos totales, plomo total y biomasa. Considerando unicamente el plomo contenido

Exposición ocupacional a plomo y pesticidas órganofosforados: efecto sobre la salud reproductiva masculina

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Sandra Yucra

2008-10-01

Full Text Available Actualmente, la exposición ocupacional a contaminantes como metales pesados y plaguicidas ha crecido por la actividad industrial, minera y agrícola. Los efectos adversos en la salud humana se presentan en el sistema respiratorio, renal, nervioso, endocrino, reproductor, siendo este último muy sensible a muchos agentes físicos y químicos generados por la actividad industrial o agrícola. Estos agentes están presentes en algunas actividades ocupacionales y en el ambiente en general. Las evidencias de estudios toxicológicos, epidemiológicos, bioquímicos y fisiológicos, demuestran que el plomo tiene efectos adversos en la salud humana de los trabajadores ocupacionalmente expuestos a diferentes concentraciones pudiendo causar infertilidad masculina. El impacto de la exposición crónica al plomo en el varón incluye reducción de la libido, alteración en la espermatogénesis (reducción en cantidad y motilidad, e incremento de formas anormales de los espermatozoides, daño cromosómico, función prostática anormal y cambios en los niveles de testosterona. Para el caso de los plaguicidas órganofosforados (OP hay un alto riesgo de exposición ocupacional y no ocupacional de estos químicos debido a su extenso uso en la agricultura y en el ambiente doméstico, se ha demostrado, que afectan también el sistema reproductor masculino actuando como tóxicos testiculares que causan alteraciones citotóxicas y citocinéticas reversibles en las células germinales, alteran la síntesis de andrógenos y la calidad seminal en los trabajadores expuestos a OP, sobre todo los individuos dedicados a la actividad agrícola. En la presente revisión se ha recopilado diferente información de los efectos adversos de la exposición ocupacional al plomo y a los plaguicidas órganofosforados sobre la función reproductiva.

Tendencia de los niveles de plomo en la atmósfera de la zona metropolitana de la Ciudad de México: 1988-1998

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Cortez-Lugo Marlene

2003-01-01

Full Text Available OBJETIVO: Describir las tendencias del plomo atmosférico asociadas a la eliminación paulatina del plomo de la gasolina y el uso de convertidores catalíticos en el auto transporte de la Ciudad de México, de 1988 a 1998. MATERIAL Y MÉTODOS: Estudio de series de tiempo que incluye las mediciones atmosféricas de plomo que se obtuvieron, entre 1988 y 1998, de nueve estaciones de la red manual de monitoreo atmosférico de la Ciudad de México. Las intervenciones evaluadas fueron la introducción de gasolina Magnasin, el uso de convertidores catalíticos y el descenso en la concentración de plomo hasta su eliminación total de la gasolina utilizada en los auto transportes. Se describen las tendencias de plomo por monitor, por zona geográfica, utilizando un modelo de regresión que incorpora una estructura de auto-correlación. RESULTADOS: La introducción de gasolina sin plomo y de los convertidores catalíticos se asoció con un descenso en la concentración de plomo atmosférico en 23%, la reducción paulatina del plomo en la gasolina ocasionó una reducción acumulada de 89% en todas las zonas estudiadas. CONCLUSIONES: La introducción de la gasolina sin plomo ha logrado abatir las concentraciones ambientales de este contaminante de una manera importante.

¿Es el plomo empleado en deportes (caza, tiro y pesca deportiva un problema de salud pública infravalorado?

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Raimon Guitart

2005-01-01

Full Text Available La munición y los pesos empleados en actividades recreativas como la caza, el tiro y la pesca deportiva han sido fabricados tradicionalmente con plomo. En España la caza y el tiro son responsables de la dispersión en la naturaleza de cerca de 6.000 toneladas anuales del metal pesado, mientras que podemos estimar en 100 las aportadas por pescadores deportivos a las zonas acuáticas. Las pocas medidas legales que varios países han adoptado en contra del uso del plomo en esos deportes se han basado en las pruebas irrefutables que indicaban que cada año fallecían intoxicadas millones de aves, que ingerían inadvertidamente esos pequeños objetos de plomo hallados abandonados en sus hábitats naturales. En este trabajo se discute si el enfoque conservacionista que se ha dado hasta ahora al problema resulta adecuado, y si las evidencias de los daños sobre los seres humanos son o no suficientes para extender todavía más esas medidas de prohibición, en especial teniendo en cuenta que en niños se considera que no hay dosis de exposición segura. Se concluye que en algunos aspectos los datos ya existen, aunque en otros los estudios tóxico-epidemiológicos son todavía escasos, sugiriendo que al tema se le ha prestado poca atención. En cualquier caso, resulta preocupante constatar que el principio de precaución no se ha aplicado para solucionar un problema cuyos efectos sanitarios serán más a largo plazo que inmediatos.

Fitoextracción De Plomo, Zinc y Cadmio de Relaves Mineros Utilizando Helianthus annuus L. (Girasol)

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Lizarbe Asmat, Katherine; Rivera López, Yaslin; Mendoza Bobadilla, Jorge; Vera Herrera, Manuel; Rodríguez Espinoza, Ronald

2017-01-01

Objetivo: Evaluar el crecimiento de Helianthus annuus L. (girasol), especie bioacumuladora de metales pesados, mediante la adición de acondicionadores orgánicos e inorgánicos al relave minero artesanal, para la fitoextracción de plomo, zinc y cadmio. Métodos: Se probaron cuatro tratamientos de diferentes proporciones relave – acondicionador (100 - 0%, 75 - 25%, 50 – 50%, 25 – 75% respectivamente), con seis repeticiones cada uno, para periodos de tiempo de 30, 60 y 90 días y mediante dos métod...

USO POTENCIAL DEL HUIZACHE (Acacia farnesiana L. Will EN LA FITORREMEDIACIÓN DE SUELOS CONTAMINADOS CON PLOMO

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Oscar Landeros-Márquez

2011-01-01

Full Text Available Se ha realizado un gran número de estudios para identificar los efectos de los metales pesados en plantas cultivadas y en algunas especies consideradas como hiperacumuladoras. Sin embargo, pocos esfuerzos se han dedicado a la evaluación de especies vegetales nativas de zonas áridas para fitorremediación. Este estudio se llevó a cabo ex situ para evaluar la tasa de fitoextracción de plomo en Acacia farnesiana L. Will. Se utilizaron árboles jóvenes (n=48, colocados en macetas plásticas, en donde se agregó una combinación de tres concentraciones de plomo (0, 250 y 500 mg·kg-1 en forma de Pb(NO32 y cuatro dosis de nitrógeno (0, 100, 300 y 500 mg·kg-1 en forma de Fosfo-Nitrato (33-03-00. Se evaluó la tasa fotosintética y la concentración de plomo en raíz, tallo y hoja. Las dosis de nitrógeno y las concentraciones de plomo por separado no produjeron diferencias significativas en la tasa fotosintética de las plantas de huizache, pero la interacción entre esos dos factores fue estadísticamente significativa (P=0.0074, encontrándose que la mayor acumulación de plomo ocurrió en la parte aérea de la planta con una media de 352.34 mg·kg-1.

El entorno de los plomos: historiografía y linaje

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García-Arenal, Mercedes

2003-12-01

Full Text Available The aim of this article is to propose new ideas concerning the authorship of the Lead Tablets from the Sacromonte, locating them, on the one hand, in the political context of the years in which they were forged, and on the other, in connection with the genealogical and historiographic works that were produced in the same period. This study proposes that the Lead Tablets were inserted into these historiographical and genealogical literature in response to their polemical nature, by making use of both History and the Arabic language as a means for ennobling Arab descent, principally by presenting the main Spanish heroes of the moment, the Christian martyrs, as Arabs. This particular use of History favours the noble lineages of the Grenadine new converts, and must have been encouraged or supported by members of those lineages. The thesis of this article is that the most likely involved in the Lead forgeries is the family Granada Venegas. This thesis is supported by showing the connections between the affair of the Lead Tablets with various members of the literary society that used to meet at the home of don Alonso Granada Venegas.

Este artículo intenta aportar nuevas ideas acerca de la autoría de los Plomos del Sacromonte y de sus objetivos poniéndolos, por un lado, en el contexto político de los años en los que fueron realizados y por otro en conexión con la historiografía y la escritura genealógica que se producen en ese mismo período. Propone que los Plomos, una fabricación morisca, se insertan en esa producción escrita, que tiene un cariz polémico al que intenta dar respuesta por medio de ennoblecer el origen árabe y la lengua árabe, presentando como árabes a los máximos héroes cristianos del momento, es decir, los mártires. Dicha escritura tiene el fin principal de favorecer a los linajes moros de Granada en un momento en que sus privilegios se veían amenazados e incluso arriesgaban ser expulsados. Debió de ser por

Exposición a plomo en niños de 6 a 12 años de edad

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Jiménez-Gutiérrez Carlos

1999-01-01

Full Text Available Objetivo. Identificar los factores de exposición asociados a las concentraciones de plomo en niños de escuelas primarias públicas y privadas de la ciudad de México. Material y métodos. Se realizó un estudio transversal en 340 niños que asistían a la escuela primaria. Las escuelas se seleccionaron por conveniencia y los niños en forma aleatoria. Se aplicó un cuestionario y se tomaron muestras de sangre venosa. Los niveles de plomo se determinaron por espectrofotometría de absorción atómica. Se compararon medias mediante la prueba t de Student-Fisher y ANDEVA; y para el análisis multivariado, regresión lineal múltiple. Debido a que los niveles de plomo no seguían una distribución normal, se transformó con logaritmo neperiano, con la que se trabajó en todo el análisis estadístico. Resultados. Las medias geométricas para escuelas privadas y públicas fueron: MG=8.76 µg/dl, IC95%=9.1-10.5; MG=11.5 µg/dl, IC95%=9.4-13.5, respectivamente. Los niveles de plomo son más elevados en los niños que asisten a la escuela pública y que presentan las siguientes características: ser varones, tener entre seis y ocho años de edad y cursar el primer o segundo grado de primaria; las madres de estos niños son profesionistas; en sus hogares se utiliza la cerámica vidriada y cerca de sus domicilios existen diferentes tipos de talleres contaminantes con plomo. Conclusiones. Los factores de exposición que predicen las concentraciones de plomo en sangre son: tener entre seis y ocho años de edad, la ocupación de la madre, la utilización de cerámica vidriada, la cercanía de diferentes tipos de talleres contaminantes con plomo a los domicilios y cursar el segundo año de primaria.

Método práctico para determinar protoporfirina libre eritrocitaria como marcador biológico ante la exposición a plomo inorgánico

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Gloria Marilé Ávalos Ávalos

2014-10-01

Full Text Available Introducción: para la evaluación de la exposición ocupacional a plomo inorgánico se utilizan diversos biomarcadores de exposición, entre ellos la determinación de plomo en sangre y la de protoporfirina libre eritrocitaria. Objetivo: determinar la fiabilidad práctica y comparativa de un método espectrofotométrico sencillo para determinar protoporfirina libre en eritrocitos como marcador biológico de la exposición a plomo inorgánico. Métodos: se estudiaron a 40 trabajadores expuestos a plomo con diferentes niveles, a cada uno de ellos se les tomó una muestra de sangre para determinar protoporfirina libre eritrocitaria y plomo, y una muestra de orina para determinar ácido aminolevulínico. Se seleccionó un grupo control de 20 trabajadores no expuestos, donde se correlacionaron las concentraciones halladas de protoporfirina libre eritrocitaria y de ácido aminolevulínico con las de plomo en sangre. Resultados: la correlación entre las concentraciones de protoporfirina libre eritrocitaria y las de plomo en sangre fue mayor y más significativa estadísticamente en los trabajadores expuestos, que la encontrada entre el ácido aminolevulínico y el plomo en sangre de los no expuestos. La técnica propuesta de determinación de protoporfirina libre eritrocitaria, además de resultar exacta, precisa y sensible, es sencilla de realizar en, prácticamente cualquier laboratorio químico con un mínimo de recursos. Conclusiones: la técnica propuesta es confiable y puede ser utilizada en una primera opción en el control higiénico-sanitario de la exposición ocupacional a plomo inorgánico, acudiéndose solamente, de ser imprescindible, a la determinación de plomo en sangre cuando las concentraciones de protoporfirina libre eritrocitaria resulten significativamente altas.

Niveles de plomo en sangre en niños de 8 a 10 años y su relación con la alteración en el sistema visomotor y del equilibrio Relationship of blood lead levels with visual-motor and equilibrium disturbances in children aged 8 to 10 years

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María Isabel Azcona-Cruz

2000-08-01

equilibrio. CONCLUSIONES: La relación negativa entre el plomo y la habilidad visomotora concuerda con los resultados encontrados en niños en otros países. Al parecer las concentraciones de plomo en sangre, que son comunes en los niños de Oaxaca, son suficientes para ocasionar una limitación visomotora de naturaleza sutil. Los resultados de este estudio señalan la necesidad de reforzar la iniciativa de reducir la exposición de los niños a las fuentes de exposición conocidas, en especial barro vidriado y, por lo tanto, reducir los niveles poblacionales de plomo en sangre.OBJECTIVE: To assess the association betwen blood lead concentrations and visual-motor coordination and equilibrium in school age children. MATERIAL AND METHODS: In November-December 1998, a cross-sectional study was conducted among 255 children aged 8-10, who attended public schools in Sector 1 of the Oaxaca State Public Education Institute. Data were collected using the Frostig Evaluation of Visual Perception test and the equilibrium subscale of the Frostig Movement Skills Test Battery. A blood sample was taken to measure lead levels by atomic absorption spectrometry. Socioeconomic data and health histories were collected for use as control variables. Statistical analysis consisted of multiple regression models to test the relationship between blood lead level and the visual-motor and equilibrium tests. We assessed the efect of lead within the model using 1 000 Montecarlo simulations. RESULTS: The geometric mean of blood lead concentrations was 11.5 µg/dl (geometric standard deviation +6.3, -5.2. After adjusting for control variables, the visual-motor integration subscale was significantly related to blood lead concentration (p> 0.042. The visual-motor integration value decreased 1.78 (95% CI -3.51, -0.06 points for each 10 µg/dl increase in blood lead concentration. Among the four sub-tests comprising the visual-motor integration subscale, only eye-hand coordination (p=0.045 and spatial relations

Niveles de plomo en sangre en niños de 8 a 10 años y su relación con la alteración en el sistema visomotor y del equilibrio

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Azcona-Cruz María Isabel

2000-01-01

equilibrio. CONCLUSIONES: La relación negativa entre el plomo y la habilidad visomotora concuerda con los resultados encontrados en niños en otros países. Al parecer las concentraciones de plomo en sangre, que son comunes en los niños de Oaxaca, son suficientes para ocasionar una limitación visomotora de naturaleza sutil. Los resultados de este estudio señalan la necesidad de reforzar la iniciativa de reducir la exposición de los niños a las fuentes de exposición conocidas, en especial barro vidriado y, por lo tanto, reducir los niveles poblacionales de plomo en sangre.

Manejo de la intoxicación por plomo en la niñez Managing childhood lead poisoning

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Morri E Markowitz

2003-01-01

Full Text Available El presente artículo hace una revisión del manejo clínico de la intoxicación por plomo en la niñez. Se menciona las definiciones de las diferentes técnicas de medición usadas para la determinación de plomo, y se destacan sus ventajas y posibles limitaciones. La medición de los niveles de plomo sanguíneo puede realizarse utilizando muestra de sangre anticoagulada por espectrofotometría de absorción atómica voltametría anódica. Sin embargo, un método más eficiente para medir las concentraciones de plomo en hueso es mediante fluorescencia de Rayos X o para la determinación sistémica en un nivel bioquímico una técnica adecuada es la determinación de los niveles de plomo en orina. El tratamiento incluye la eliminación de la fuente de exposición, cambios en los hábitos de los niños y una dieta adecuada en calcio y hierro. La quelación con edetato de calcio y succimer elimina el plomo del esqueleto, el cual es eliminado por riñón; puede salvar vidas cuando la intoxicación es importante, y existe una reducción a corto plazo seguida de un aumento subsecuente de los niveles de plomo sanguíneo. En casos graves suele requerirse de dosis repetidas. La terapia de quelación puede ser necesaria en casos de niveles de plomo sanguíneo por arriba de 45 µg/dl. La quelación reduce los niveles de plomo sanguíneo y los síntomas asociados, sin embargo, la disminución cognoscitiva puede ser irreversible, por lo que la utilización de medidas preventivas es mucho mejor que las de curación.This paper reviews the clinical management of children with lead poisoning. A first step is to define the measures to be used in their assessment and be aware of the limitations. Measurements of blood lead levels can be made on anti-coagulated whole blood samples using either: atomic absorption spectroscopy or anodic stripping voltametry. However a more accurate method is fluorescent RX'ray of the skeleton or systematic biochemical tests of lead

Modelo sistémico para evaluar la recuperación de suelos contaminados por plomo en el distrito de Concepción

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Yarasca Bejarano, José Luis

2015-01-01

La fitorremediación se considera una tecnología viable y rentable emergente que tiene como responsabilidad limpiar los elementos traza de metales pesados como es el caso del plomo. Este método no ha sido muy propagada por la existencia de diversas dudas al respecto. Estos pueden resumirse como la incertidumbre del sistema de comportamientos en diferentes escenarios, tales como: contaminante, la concentración de contaminante y el comportamientos de la fisiología de la planta. Enfoques ante...

Influencia de algunas variables en la biosorción de plomo con residuos agrícolas

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Hernáinz Bermúdez de Castro, Francisco; Blázquez García, Gabriel; Calero de Hoces, Mónica; Martín-Lara, Mª Ángeles

2008-01-01

En este trabajo se ha estudiado la biosorción de plomo presente en medios acuosos utilizando como sólidos sorbentes hueso de aceituna, alpeorujo y ramón del olivo, analizando la influencia sobre el proceso del pH, concentración de biosorbente, tamaño de partícula y tiempo de contacto. Los resultados muestran que en medios muy ácidos no se produce retirada de plomo con ninguno de los sólidos, aumentando el porcentaje de plomoretirado a medida que se eleva el pH del medio hastaalcanzar un valor...

Asociación entre plomo en sangre y parámetros sociodemográficos en población infantil

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Maritza Rojas

2003-08-01

Full Text Available OBJETIVO: Establecer la relación entre concentración de plomo en sangre (Pb-S y parámetros demográficos y socioeconómicos, en una población infantil. METODOS: Se estableció la relación entre la concentración de plomo en sangre (Pb-S, de 243 niños (promedio de edad 5,94±2,78 años, que asistieron al Centro de Investigaciones Toxicológicas de la Universidad de Carabobo (CITUC, Venezuela (periodo 1998-2000. Se utilizó tecnología de Sistemas Geográficos de Información (SGI, ubicando espacialmente a los niños, asociando de forma gráfica la procedencia de éstos con los resultados analíticos. RESULTADOS: El promedio de Pb-S de la población total (11,62 ug/dl, fue significativamente superior al límite permisible (CDC=10 ug/dl. El número de niños con valores superiores al límite permisible de Pb-S (VSLP [150; 61,7%], fue significativamente alto (p<0,01 con respecto a la población total. Al asociar mediante regresión logística, la frecuencia de niños con VSLP con los sectores de procedencia, se demostró que los sectores 12, 16 y 28 presentaron correlaciones parciales directas significativas (R=0,1189; p<0,01; R=0,1202, p<0,01 y R=0,1189; p<0,01 respectivamente. Al asociar la frecuencia de niños con VSLP y su categorización socioeconómica, el análisis de regresión logística reveló que para los niños con VSLP, la probabilidad de pertenecer a la categorización C se incrementa en un factor de 7.286. CONCLUSIÓNS: El estudio confirma que la utilización de SGI y métodos epidemiológico-estadísticos, extiende las posibilidades de prevención de enfermedades producidas por contaminantes como el Pb y que correlacionando datos geográficos y de salud, se pueden identificar áreas de "alto riesgo", conduciendo a una acción pro-activa de salud pública.

Exposición ocupacional a plomo inorgánico en una imprenta de la Ciudad de México Occupational exposure to inorganic lead in a printing plant in Mexico City

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Guadalupe Aguilar-Madrid

1999-01-01

�mbito de la exposición ocupacional al plomo no existen estudios publicados que permitan establecer niveles máximos permisibles tanto ambientales como biológicos. Por medio de este estudio se intenta contribuir al establecimiento de una normatividad de plomo en sangre, que actualmente está en discusión en México.Objective. To describe occupational lead exposure and its biological indicators in workers in a printing company. Material and methods. An epidemiological and industrial hygiene research was undertaken. Lead was measured in the air of work environment and on the hands of the participants; additionally, subjects underwent a venous blood samples for the determination of whole blood lead by atomic absorption spectrophotometry; and a bone lead measurement using a spot-source 109Cd K-X-ray fluorescence instrument. Also, a standardized questionnaire was applied. We obtained information on demographic and life styles factors, work history, type of work, position and activity within the company. Results. Of the 209 workers, 117 agreed to participate and 90 (83.3% males and 16.7% females completed all phases of the study. The average lead concentrations were: in air samples, of 0.94 mg/m³; in hands before washing, of 6 802 mg/m²; in hands after washing, of 194 mg/m²; in whole blood, of 12.3 mg/dl; and in tibia and fibula, of 25.9 and 43.3 mg Pb/g of bone mineral, respectively. Important variations in these measurements were observed according to the workers post. Conclusions. Worldwide, lead exposure levels have been used to evaluate acute exposures being in the workplace. The higher lead levels find in the bone of the workers in this study are similar to other occupational studies in the United States of America and suggest that the accumulated metal in bone may be an important endogenous exposure source, and here its measurement importance. However in developing countries because its high costs per application, the measurements in bone lead become limited to

Evaluación de plomo en el ambiente ocupacional de una industria de baterías

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Lina V. Hernández

2011-03-01

Full Text Available Se realizó un estudio de evaluación de riesgo ocupacional por la presencia de plomo en el aire, en una mediana industria de reciclaje y fabricación de baterías eléctricas ubicada en Bogotá, Colombia. Se tomaron muestras de aire en la zona de respiración de las personas, mediante bombas de muestreo personal con filtros de acetato de celulosa para captación de partículas, y se aplicó la metodología de muestreo parcial con muestras consecutivas. El contenido de plomo fue determinado por absorción atómica con llama. Se encontraron concentraciones de plomo en el aire entre no detectable y 6,23 mg Pb/m3 de aire. Los resultados indican que se supera el valor límite umbral (TLV de 0,04 mg Pb/m3 de aire, corregido para la jornada laboral de 48 horas, en actividades de fundición, formación de placas, empaste y oficios varios. La evaluación de riesgo ocupacional confirma el riesgo en todos los puestos de trabajo y en las actividades señaladas durante la mayoría de los muestreos realizados.

Intervención ambiental en sitios contaminados por plomo: la experiencia en los Estados Unidos de América

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Ceto Nicholas

2003-01-01

Full Text Available Durante una década, los organismos estatales y federales han trabajado de manera conjunta con las comunidades a lo largo del territorio estadounidense, con el objeto de valorar el riesgo a la salud que implica la contaminación por plomo en las zonas residenciales. A menudo dichas comunidades han estado vinculadas con instalaciones destinadas anteriormente a actividades como la minería y la metalurgia; sin embargo, existen otras industrias como por ejemplo la fabricación de pinturas y el reciclaje de baterías, también identificadas como fuentes de contaminación por este metal. La vasta experiencia en las tareas de limpieza de los sitios contaminados ha puesto de manifiesto que los amplios programas destinados a identificar y manejar las vías de exposición pueden ayudar, de manera efectiva, a disminuir los niveles de plomo en sangre de las poblaciones más suceptibles, como la de los de niños en edades tempranas. Los programas de intervención ambiental son más efectivos cuando en las localidades afectadas se ejecutan programas de educación/intervención en salud, orientados al desarrollo de estrategias individualizadas para manejar el riesgo que implica la presencia de dicho metal en el ambiente.

Análisis hidrodinámico de la inyección de partículas durante la refinación de plomo Análisis hidrodinámico de la inyección de partículas durante la refinación de plomo

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Antonio Romero Serrano

2012-02-01

Full Text Available Pyro-refining is one of the techniques used in recycling lead. Two significant stages in theprocess are decopperization and desilverization, which are traditionally done by addingpowdered Sulfer and Zinc at the surface of the lead bath and then mixing it with a propeller.The efficiency of this process has been improved by using a submerged lance to injectthe reactants into the interior of the lead bath, but the hydrodynamics of this new methodhas not yet been studied until now. The aim of this study was to refine the techniquesfor injecting particles into lead baths by performing mathematical simulations using theCOMSOL 3.4 software. Residence and mixing times were produced for different injectionvelocities, and the simulation results for residence times were validated by experimentaldata obtained in the laboratory.Una técnica en el reciclaje de plomo es la piro-refinación, en donde las etapas de interés son: el decobrizado y el deplatado; que consisten en adicionar azufre y zinc en polvo, respectivamente en la superficie del baño de plomo y posteriormente se agita con una hélice. Este procedimiento ineficiente, se optimizo al inyectar los reactivos a través de una lanza en el seno del baño, lo cual incremento la eficiencia del proceso. El aspecto hidrodinámico del proceso de inyección no ha sido aún estudiado, por lo que en este trabajo, se estudio el comportamiento hidrodinámico de la inyección de partículas a través de una lanza sumergida en baños de plomo mediante simulación matemática con la aplicación del software COMSOL 3.4. Se obtuvieron los tiempos de residencia y mezclado a diferentes velocidades de inyección. Los resultados del tiempo de residencia de la simulación se validaron con datos obtenidos experimentalmente en pruebas realizadas a nivel laboratorio obteniendo una buena similitud entre ambos.

Validación de la metodología para la determinación cuantitativa de plomo en tintes cosméticos disponibles en el mercado nacional por espectroscopia de absorción atómica con llama

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Paulina Silva Trejos

2008-04-01

Full Text Available Se validó la metodología analítica para determinar cuantitativamente plomo en tintes cosméticos disponibles en el mercado nacional, por el método de espectroscopia de absorción atómica con llama. Las muestras se digirieron por digestión húmeda con HNO3 al 65 % m/men horno de microondas; el porcentaje de recuperación para la digestión de muestras de 0,25 g y 0,45 g en 5,00 mL fue de 100,5±0,5. El ámbito de linealidad óptimo fue del límite de detección a 5,0 mg/L con un coeficiente de correlación de 0,9998.Los límites de detección y los límites de cuantificación determinados gráficamente por el método de corredor de errores para regresión lineal fueron de 0,12 ±0,02 mg/L y 0,21±0,02 mg/L, respectivamente. Se evaluó la precisión determinando la repetitividad como desviación estándar de 5 réplicas de un tinte positivo para plomo, de acuerdo con la definición de la ISO,2√2*σ, y se obtuvo un valor de 2,3. La veracidad se determinó por medio de los porcentajes de recuperación evaluados, agregando alícuotas de patrones de plomo a muestras de tinte y comparándolo con muestras de igual masa a las que no se les realizó adición. Las muestras de tintes se obtuvieron en puestos de venta, tales como farmacias, suplidoras de belleza,supermercados, centros de ventas de productos naturales y el mercado central de San José. De los tintes analizados, de marca Youthair, de fabricación norteamericana, Doni, Mont D’Or, Matador y Siempre Joven, producidos localmente, contienen acetato de plomo como ingrediente activo

Niveles de plomo sanguíneo en madres y recién nacidos derechohabientes del Instituto Mexicano del Seguro Social

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Navarrete-Espinosa Joel

2000-01-01

Full Text Available OBJETIVO: Establecer la relación entre el nivel de plomo sanguíneo materno (PSM y el de sangre en cordón umbilical (PSC al momento del parto, así como determinar los principales predictores del PSM en derechohabientes del Instituto Mexicano del Seguro Social (IMSS, en el Distrito Federal (D.F.. MATERIAL Y MÉTODOS: Se realizó un estudio transversal en el que se reclutaron voluntarias con embarazo normoevolutivo y se les tomaron muestras de sangre al momento del parto, en cuatro hospitales del IMSS en el D.F., de 1991 a 1993. Se tomó, además, muestra de sangre de cordón umbilical. Los datos fueron analizados mediante regresión lineal simple y múltiple. RESULTADOS: Se estudiaron un total de 1 404 binomios madre-hijo; el promedio de edad de las madres fue de 25 años. La media de PSM fue 10.7 ± 6.5 µg/dl; no se encontraron variaciones significativas por hospital, edad o estado civil. Para el PSC la media fue de 10.4 ± 6.2 µg/dl. Por cada aumento en una unidad logarítmica de PSM, el PSC aumenta 0.62 (p<0.01 unidades logarítmicas. La correlación entre ambos fue de 0.61 (p<0.01. Los principales predictores de PSM fueron el uso de loza vidriada, el consumo de leche y jugo de naranja, estos últimos se asociaron inversamente con el PSM. Un 47% de las madres y 50% de los niños tuvieron valores superiores a 10 µg/dl. En 578 recién nacidos se registraron niveles de plomo superiores a los de la madre. CONCLUSIONES: Se sugiere continuar la línea de investigación para proponer tipos de intervención.

PLOMO Y ARSÉNICO EN LA SUBCUENCA DEL ALTO ATOYAC EN TLAXCALA, MÉXICO

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Edelmira García-Nieto

2011-01-01

Full Text Available Se evaluaron indicadores ambientales en el sistema hidrológico Zahuapan-Atoyac (SH:ZA, en Tlaxcala, México. Una región impactada por descargas de aguas residuales de origen urbano, agrícola e industrial. Las muestras fueron colectadas en la primavera del año 2008, época de estiaje. Se seleccionaron 16 estaciones de muestreo; abarcando desde el nacimiento del río Zahuapan, incluyendo tres muestras del río Atoyac, hasta su salida del estado de Tlaxcala. En las muestras de agua se midieron arsénico, plomo, pH y temperatura, en sedimentos; arsénico, plomo, textura, contenido de materia orgánica, carbono orgánico total, pH y conductividad eléctrica de acuerdo con NMX-AA-051-SCFI-2001, Goyberg-Reín y Vázquez, 2003 y la NOM-021-SEMARNAT-2000. Los resultados mostraron que el intervalo de concentraciones de arsénico osciló de 0.06 a 0.87 mg·L-1 en agua y de 1.3 a 127 mg·kg-1 en sedimento. Mientras que el plomo alcanzó niveles hasta de 1.05 mg·L-1 en agua del sitio denominado El Ojito y 89.5 mg·kg-1 en sedimento de la estación Apizaco. Estos niveles superaron las normas nacionales e internacionales establecidas para agua de consumo humano y protección de la vida acuática. Los resultados sugieren un aporte antropogénico en algunas estaciones que se suma a la contaminación de origen natural.

Intoxicación por plomo y otros problemas de salud en niños de poblaciones aledañas a relaves mineros

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Jonh Astete

2009-01-01

Full Text Available Objetivos. Determinar los niveles de plomo y otros problemas de salud en menores de 10 años residentes en las comunidades de Quiulacocha y Champamarca, Pasco. Materiales y métodos. Estudio transversal realizado en septiembre de 2005. Se incluyó a todos los niños de ambas comunidades altoandinas aledañas a relaves mineros. Se realizó medición de los niveles de plomo y hemoglobina en sangre así como la evaluación antropométrica y del desarrollo psicomotor. Resultados. La prevalencia de intoxicación por plomo (Pb>10 µg/dL fue de 84,7%, la media de plumbemia fue 15,79 ± 4,85 µg/dL (rango: 6,17-34,53 µg/dL. La mayoría (55,8% de los niños de ambas comunidades estaban con desnutrición crónica, 23,0% tenían anemia, y 5,9% tenían retardo mental. Los niños de Quiulacocha tenían un desarrollo psicomotor normal en 79,2% de los casos y en Champamarca 85,4%. Conclusiones. Cuatro de cada cinco niños de estas comunidades tiene intoxicación plúmbica. Los relaves mineros son una fuente de contaminación por plomo para los niños que viven en zonas aledañas, se deben realizar intervenciones en estas comunidades.

Evaluación del efecto tóxico del acetato plomo y el cloruro de cromo sobre el metabolismo bacterial anaerobio

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Beatriz Wills

2004-01-01

Full Text Available Se presentan los resultados del estudio de toxicidad del cloruro de cromo (CrCl3 y el acetato de plomo (CH3COO2Pb del lodo de un reactor anaerobio de flujo ascendente y manto de lodos (UASB, aclimatado y estabilizado en el laboratorio con una solución de suero en polvo sintético; los ensayos de toxicidad se realizaron en botellas serológicas de 60 mL, se utilizaron como sustratos soluciones de ácido fórmico y suero en polvo sintético y se ensayaron concentraciones de cloruro de cromo en el rango de 1.000 a 5.000 mg/L, y de 1.000 a 10.000 mg/L para el acetato de plomo. Durante 72 horas se valoró la producción de metano en mL y el comportamiento del potencial redox en mV.Se presentaron reducciones del 50% en la producción de metano a concentraciones de 3.322 mg/L para cloruro de cromo y 1.415 mg/L para el acetato de plomo cuando el sustrato fue ácido fórmico, y a 2.291 mg/L para el cloruro de cromo y 1.982 mg/L para el acetato de plomo cuando el sustrato fue suero en polvo sintético.En síntesis, el artículo demuestra que las bacterias metanogénicas tienen un grado de resistencia cuantificable con respecto a las diferentes concentraciones de metales aplicados

Lead exposure among young urban women Exposición a plomo en mujeres jóvenes residentes en zonas urbanas

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Jacqueline M. Moline

1999-11-01

estudio de cohorte. Material y métodos. Las mujeres elegibles fueron aquellas que acudieron al centro de salud de la ciudad de Nueva York durante 1995-1998, tenían entre 18 y 25 años de edad y estaban sanas. El reclutamiento se llevó a cabo por los proveedores de salud, el coordinador del estudio y las mismas mujeres. Se administraron cuestionarios detallados y se obtuvieron muestras sanguíneas en donde se determinaron los niveles de plomo en sangre total, ferritina y hematocrito. Resultados. A la fecha se han reclutado 239 mujeres. La población es predominantemente de grupos minoritarios: 62% africanas-americanas, 33% hispánicas y 5% caucásicas-asiáticas. El promedio de edad es de 19.3 años. El reclutamiento de las participantes se hace invitando a las mujeres que previamente han aceptado participar en el estudio (55%. Algunas se enteraron del estudio por los proveedores de salud. El nivel medio de plomo fue de 2.1±1.7 µg/dl, el cual es consistente con las encuestas nacionales más recientes de Estados Unidos. Conclusiones. Los niveles de plomo en sangre son bajos en mujeres de grupos minoritarios, jóvenes, en edad reproductiva, que residen en zonas urbanas de la ciudad de Nueva York. En esta población el reclutamiento se incrementó sustancialmente con la ayuda de las participantes y la comunidad de proveedores de salud.

Methodological issues related to studies of lead mobilization during menopause Consideraciones metodológicas relacionadas con estudios sobre movilización de plomo durante la menopausia

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Gertrud S. Berkowitz

1999-11-01

Full Text Available While there has been a substantial decline in lead exposure in the United States during the past two decades, mobilization of existing lead stored in bone potentially represents an important endogenous source of exposure for menopausal women. It has been hypothesized that lead may be mobilized from skeletal stores during conditions of high bone turnover, such as during menopause. However, such mobilization has not been documented in prospective studies. This discussion is focussed on some of the methodological difficulties to be anticipated in longitudinal studies of lead mobilization specific to menopause and the issues that need to be taken into account when evaluating the results of such studies. To evaluate whether lead mobilization occurs during menopause, a prospective repeated measures design is needed using X-ray fluorescence analysis of lead in bone and serial measurements of blood lead. Potential confounders and effect modifiers also need to be taken into account in the statistical analysis.Mientras que la exposición a plomo ha declinado sustancialmente en Estados Unidos durante las dos décadas pasadas, la mobilización del plomo almacenado en los huesos representa potencialmente una importante fuente de exposición endógena en mujeres menopáusicas. No obstante, tal movilización no ha sido documentada por estudios prospectivos. La presente discusión se enfoca en algunas de las dificultades metodológicas a se anticipadas en estudios longitudinales de mobilización de plomo específicamente en la menopausia, y los aspectos que necesitan ser considerados cuando se evalúan los resultados de tales estudios. Para evaluar si durante la menopausia el plomo es mobilizado, se requiere de un diseño prospectivo con mediciones repetidas utilizando análisis de fluorescencia de rayos-X para determinar el plomo en hueso y una serie de mediciones de plomo en sangre. Los potenciales confusores y modificadores del efecto también deben tomarse

Optimización de la recuperación del sulfuro de plomo fino y su impacto económico en Volcan Compañía Minera concentradora Victoria

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Guerreros Meza, Julio Emilio

2015-01-01

El proceso del tratamiento de los minerales sulfurados tiene diferentes operaciones unitarias. Se inicia desde el desbroce del mineral, pasando luego por la planta concentradora para obtener el concentrado. Durante estos procesos el mineral se va reduciendo de tamaño con la finalidad de liberarlos y posterior concentración en un proceso de flotación diferencial, pero los minerales que contienen el sulfuro de plomo son por su característica frágiles al impacto, por este inconveniente el tra...

Cuantificación de plomo, cadmio y cromo mediante sialoquímica

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GONZÁLEZ MIREYA

1997-01-01

Full Text Available Objetivo. Determinar las concentraciones de plomo, cadmio y cromo, y establecer su posible asociación con diferentes factores sociodemográficos. Material y métodos. Se seleccionó una muestra representativa de 100 estudiantes de posgrado de la Facultad de Odontología de la Universidad Nacional Autónoma de México (UNAM, a los cuales se les colectó saliva total no estimulada. Dichas muestras fueron analizadas por espectrofotometría de absorción atómica con horno de grafito. Resultados. Metales pesados como el plomo, el cadmio y el cromo se encuentran en concentraciones mucho más altas que las informadas en la literatura: Pb, = 3.10 m g/dL-1, máxima: 16.8 my g/dL-1, y mínima: 0.04 my g/dL-1; Cd, = 0.25 my g/dL-1, máxima: 2.04 my g/dL-1, y mínima: 0.004 my g/dL-1; y Cr, = 1.43 my g/dL-1, máxima: 4.82 my g/dL-1, y mínima: 0.05 my g/dL-1. Asimismo, variables como la zona de residencia, el sexo, la edad y la ingesta de comida enlatada no influyen en los niveles de plomo y cromo. Sin embargo, en el caso del cadmio y la edad existe una asociación inversa (ji²= 5.9012, p<= 0.05; gamma = -0.5224, p<= 0.05. Conclusiones. La sialoquímica juega un papel importante en la detección de contaminantes, fármacos, drogas y enfermedades locales y sistémicas. La contaminación por metales pesados sigue siendo un problema de salud pública, por lo que el gobierno debe consolidar un programa cuyo objetivo sea eliminar los diferentes contaminantes del ambiente. Asimismo, se deben realizar otros estudios para verificar la asociación de variables como sexo, edad, uso de cerámica vidriada, alimentación y zona de residencia con las concentraciones de metales pesados en saliva.

Neurotoxicity and aggressiveness triggered by low-level lead in children: a review Neurotoxicidad y agresividad desencadenadas por bajos niveles de plomo en niños: una revisión

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Kelly Polido Kaneshiro Olympio

2009-09-01

Full Text Available Lead-induced neurotoxicity acquired by low-level long-term exposure has special relevance for children. A plethora of recent reports has demonstrated a direct link between low-level lead exposure and deficits in the neurobehavioral-cognitive performance manifested from childhood through adolescence. In many studies, aggressiveness and delinquency have also been suggested as symptoms of lead poisoning. Several environmental, occupational and domestic sources of contaminant lead and consequent health risks are largely identified and understood, but the occurrences of lead poisoning remain numerous. There is an urgent need for public health policies to prevent lead poisoning so as to reduce individual and societal damages and losses. In this paper we describe unsuspected sources of contaminant lead, discuss the economic losses and urban violence possibly associated with lead contamination and review the molecular basis of lead-induced neurotoxicity, emphasizing its effects on the social behavior, delinquency and IQ of children and adolescents.La neurotoxicidad adquirida inducida por la exposición prolongada a bajos niveles de plomo tiene una importancia especial en los niños. Una plétora de publicaciones recientes ha demostrado el vínculo directo existente entre la exposición a bajos niveles de plomo y el déficit en el desempeño neuroconductual-cognitivo manifestado desde la infancia hasta el final de la adolescencia. En numerosos estudios, la agresividad y la delincuencia juvenil también se han considerado síntomas de la intoxicación por plomo. Se han identificado y explicado ampliamente varias fuentes ambientales, laborales y domésticas de contaminación por plomo y los riesgos resultantes para la salud, pero aún son numerosos los casos de intoxicación por plomo. Se necesitan urgentes políticas de salud pública para prevenir la intoxicación por plomo de manera de reducir los daños y las pérdidas, tanto individuales como para la

Estudio de los niveles de plomo, cadmio, zinc y arsénico, en aguas de la provincia de Salamanca

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Blanco Hernández Angel Luis

1998-01-01

Full Text Available FUNDAMENTOS: Conocer el grado de contaminación por plomo, cadmio, cinc y arsénico de las aguas de la provincia de Salamanca y su relación con la zona de procedencia de las muestras y el punto de recogida de las mismas. MÉTODO: Estudio epidemiológico transversal, observacional y descriptivo. Se han estudiado aguas procedentes de redes de abastecimiento, fuentes, manantiales, pozos, ríos, riveras y lagunas de la provincia de Salamanca, analizándose los contenidos de plomo, cadmio, zinc y arsénico de 180 muestras, mediante espectroscopía de absorción atómica. Se han comparado los niveles de contaminación por los cuatro elementos de las muestras de agua entre las cuatro unidades comarcales de la provincia. Se han comparado los niveles de contaminación por los cuatro elementos entre las aguas procedentes de redes de abastecimiento y aquellas muestras de pozos, fuentes, manantiales y aguas de superficie. RESULTADOS: Los resultados indican que un 56% de las muestras analizadas superan las concentraciones máximas admisibles de cadmio, y un 28% del total de muestras analizadas supera las concentraciones máximas admisibles de plomo, según la legislación vigente presentando niveles tolerables de zinc y arsénico. No se han observado diferencias importantes en el grado de contaminación de las aguas por los elementos estudiados entre las cuatro unidades comarcales de la provincia. No se han observado diferencias en los niveles de contaminación por los cuatro elementos entre las aguas procedentes de redes de abastecimientos y aquellas muestras de pozos, fuentes, manantiales y aguas de superficie. CONCLUSIONES: Los resultados sugieren que las aguas de la provincia de Salamanca presentan de forma "natural" altos contenidos de cadmio y plomo, probablemente debido a las características geológicas del terreno.

Acumulación de plomo en hueso y sus efectos en la salud Lead storage in bone and its effects on health

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Luz Helena Sanín

1998-07-01

Full Text Available Los efectos nocivos del plomo han sido conocidos desde tiempos antiguos por su amplia gama; este metal afecta prácticamente todos los órganos y sistemas del cuerpo humano. Recientemente se han documentado efectos tóxicos crónicos en los sistemas cardiovascular y nervioso, con niveles que antes se consideraban seguros. El sitio primario de almacenamiento de plomo en el organismo es el hueso, pero sólo hasta fechas recientes se ha clarificado la significancia toxicológica de este hecho. En este artículo se analiza el papel del plomo en hueso como fuente de exposición endógena, como biomarcador de exposición crónica y como tejido blanco. Se presentan además los avances recientes para la medición de plomo en hueso mediante los rayos X-fluorescentes (XRF. Finalmente se revisa la importancia, para la salud pública, de estudiar y medir el plomo en hueso en lugares con una historia de exposición crónica como la Ciudad de México y en los ambientes ocupacionales, especialmente como fuente remanente de exposición. Se analiza especialmente el caso de mujeres en edad reproductiva, quienes pueden convertirse en fuentes de exposición para el feto y para el niño amamantado.The adverse effects of lead have been known for long since the metal affects practically all organs and systems of the human body. Recently, toxic effects have been reported in the cardiovascular and nervous systems at lead levels previously considered to be secure. The main lead storage site in the body is bone. The toxicologic significance of this fact has been clarified only recently. The present study analyzes the role of lead as an endogenous source of exposure, as a chronic exposure biomarker and as a target organ. Recent advances to measure bone lead through fluorescent X-Rays are discussed. Additionally, the importance of bone lead from a public health perspective in places with a chronic history of exposure such as Mexico City, and in some occupational

Evolución temporal de la contaminación por plomo y cadmio en la zona intermareal de la ría de Vigo

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M. Pérez López

2004-12-01

Full Text Available En el presente trabajo se han recogido muestras de lapa (Patella vulgata L. y alga verde (Ulva lactuca en un mismo punto de muestreo de la ría de Vigo, con una periodicidad mensual, a lo largo de un año, analizándose por medio de voltamperometría de redisolución anódica la concentración en dos metales pesados con claras repercusiones toxicológicas, cadmio y plomo, en estas muestras, así como en el agua marina. Los resultados obtenidos mostraron la mayor concentración de ambos metales en los tejidos blandos de las lapas frente a las valvas de estos moluscos, con valores máximos en el caso del plomo próximos a 3 ppm (valva de lapa, mientras que para el cadmio se situó en torno a 1,1 ppm (alga verde. El estudio estadístico permitió poner en evidencia una clara correlación estadística entre los valores de cadmio y plomo cuantificados en las muestras de algas.

Niveles sanguíneos de plomo en neonatos hijos de madres consumidoras de "basuco": estudio comparativo

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Martha Piedad Restrepo

1988-02-01

Full Text Available

Obtention of cocaine clorhydrate from coca leaves requires the use of gasoline; therefore residues such as lead may remain in the base paste (basuca; the latter is smoked, under the name basuco, mixed with tobacco or marijuana; It is conceivable that the smoker takes up lead residues that Increase lead blood levels; we wanted to determine whether the use of basuco during pregnancy could produce such effect In the newborn infant. Serum lead concentrations were measured In 19 newborn children and In 18 of their mothers. The latter were basuco consumers. They were compared to those of 20 non consuming delivering women along with 19 of their newborn Infants. Measurements were performed on a Perkin-Palmer model 2380 atomic absorption

spectrophotometer. Women were divided in four groups according to the degree of consumption, as follows: mild, moderate, Intense or non existent. Mean levels and SDs in the children were respectively: 13.5 ± 9.4; 15.8 ± 6.5; 16.6 ± 7.8; 6.9 ± 5.0 ug/dl; and In their mothers: 13.3 ± 4.6; 13.5 ± 6.9; 16.2 ± 4.9; 8.4 ± 4.6 ug/dl Statistic analysis revealed highly significant differences between mothers and children exposed to basuco and those that were not exposed. No difference was observed ac. cording to the degree of consumption. In conclusion: newborn from basuco consuming mothers have Increased lead blood levels; the long term effects of such alteration should be the subject of further studies.

Análisis de Cadmio y Plomo en aguas superficiales por potenciometría de Stripping

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Juan Miguel Arias

2010-12-01

Full Text Available Se realizó la implementación y validación de una metodología analítica para determinar la presencia de cadmio y plomo en aguas supjerficiales como herramienta para la descripción del estado actual y el control cualitativo y cuantitativo de las descargas de estos metales peligrosos en los cuerpos de agua.

Asociación entre plomo en sangre y parámetros sociodemográficos en población infantil Association between blood lead and sociodemographic parameters among children

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Maritza Rojas

2003-08-01

Full Text Available OBJETIVO: Establecer la relación entre concentración de plomo en sangre (Pb-S y parámetros demográficos y socioeconómicos, en una población infantil. METODOS: Se estableció la relación entre la concentración de plomo en sangre (Pb-S, de 243 niños (promedio de edad 5,94±2,78 años, que asistieron al Centro de Investigaciones Toxicológicas de la Universidad de Carabobo (CITUC, Venezuela (periodo 1998-2000. Se utilizó tecnología de Sistemas Geográficos de Información (SGI, ubicando espacialmente a los niños, asociando de forma gráfica la procedencia de éstos con los resultados analíticos. RESULTADOS: El promedio de Pb-S de la población total (11,62 ug/dl, fue significativamente superior al límite permisible (CDC=10 ug/dl. El número de niños con valores superiores al límite permisible de Pb-S (VSLP [150; 61,7%], fue significativamente alto (pOBJECTIVE: To determine the relationship between blood lead concentration (Pb-S, and sociodemographic parameters among children. METHODS: Blood lead concentration (Pb-S was determined in 243 children (aged 5.94±2.78 years in the district of Valencia. The required analysis was performed at the Center for Toxicological Investigations of University of Carabobo (CITUC, Venezuela, between January 1st, 1998 to December 31st, 2000. Geographical Information Systems (GIS technology was used for data mapping. RESULTS: Average Pb-S (11.62 ug/dl was significantly higher than the allowed levels. One hundred and fifty (61.7% children had Pb-S levels above the allowed concentration (VSLP and this amount was significantly high in relation to the total number of subjects studied. The logistic regression analysis showed a significant association of sectors 12 (status A and 16 and 28 (status C with VSLP (R=0.1189; p<0,01; R=0.1202, p<0,01 and R=0.1189; p<0.01, respectively. Odds ratio showed that children from status C are 7,286 times more likely to have Pb-S VSLP than those from A or B. CONCLUSIONS: This

Tendencia de los niveles de plomo en la atmósfera de la zona metropolitana de la Ciudad de México: 1988-1998 Trends in atmospheric concentrations of lead in the Metropolitan Area of Mexico City: 1988-1998

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Marlene Cortez-Lugo

2003-01-01

Full Text Available OBJETIVO: Describir las tendencias del plomo atmosférico asociadas a la eliminación paulatina del plomo de la gasolina y el uso de convertidores catalíticos en el auto transporte de la Ciudad de México, de 1988 a 1998. MATERIAL Y MÉTODOS: Estudio de series de tiempo que incluye las mediciones atmosféricas de plomo que se obtuvieron, entre 1988 y 1998, de nueve estaciones de la red manual de monitoreo atmosférico de la Ciudad de México. Las intervenciones evaluadas fueron la introducción de gasolina Magnasin, el uso de convertidores catalíticos y el descenso en la concentración de plomo hasta su eliminación total de la gasolina utilizada en los auto transportes. Se describen las tendencias de plomo por monitor, por zona geográfica, utilizando un modelo de regresión que incorpora una estructura de auto-correlación. RESULTADOS: La introducción de gasolina sin plomo y de los convertidores catalíticos se asoció con un descenso en la concentración de plomo atmosférico en 23%, la reducción paulatina del plomo en la gasolina ocasionó una reducción acumulada de 89% en todas las zonas estudiadas. CONCLUSIONES: La introducción de la gasolina sin plomo ha logrado abatir las concentraciones ambientales de este contaminante de una manera importante.OBJECTIVE: To describe the trends in airborne lead levels and their association with the control measures implemented from 1988 to 1998 to phase out lead from gasoline that included the introduction of a lead-free gasoline and the use of catalytic converters in automobiles in Mexico City. MATERIAL AND METHODS: Data of atmospheric lead levels were obtained from the 9 field stations included in the local air quality monitoring network (RMMA. Trends for airborne lead are shown by monitor, monitoring area and for the entire metropolitan zone. Analysis of data was performed using linear regression models including autocorrelation analysis. The models were validated by standard diagnostic

Uso de los datos de plumbemia para evaluar y prevenir el envenenamiento infantil por plomo en Latinoamérica Use of blood lead data in epidemiological studies to assess and prevent childhood lead poisoning in Latin America

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Isabelle Romieu

2003-01-01

Full Text Available La exposición al plomo es una amenaza seria para la salud de los niños, que se encuentra ampliamente distribuida en la Región de América Latina. Los funcionarios de salud pública necesitan identificar fuentes de exposición al plomo, así como sus efectos en la salud, para poder diseñar, implantar y evaluar las actividades preventivas y de control. Para evaluar la magnitud del problema del plomo es necesario definir tres elementos clave: a las fuentes potenciales de exposición, b los indicadores que se utilizarán para evaluar los efectos en la salud y la exposición en el medio ambiente, y c las estrategias de muestreo de la población en riesgo. Se pueden utilizar varias estrategias con el fin de seleccionar la población blanco dependiendo de los objetivos del estudio, el tiempo límite y los recursos disponibles. Si el objetivo es evaluar la magnitud y las fuentes del problema pueden emplearse los siguientes métodos de muestreo: a el muestreo al azar basado en la población; b el muestreo al azar basado en las facilidades dentro de los hospitales, las guarderías o las escuelas; c el muestreo objetivo de los grupos de alto riesgo; d el muestreo de conveniencia (de voluntarios, y e el reporte de los casos (éste puede conducir a la identificación de las poblaciones en riesgo, además de las fuentes de exposición. Para todos los diseños de muestreo, la información debe incluir tanto el uso de un cuestionario para el informe general de los participantes y de las fuentes potenciales locales de exposición, como la recolección de las muestras biológicas. En la interpretación de los datos se debe considerar el tipo de muestreo utilizado, el porcentaje de falta de respuesta y los factores que pueden influir en las mediciones del plomo en sangre, como la edad y la variación de la temporada. Las mediciones del plomo en la sangre se deben integrar dentro de una estrategia general para la prevención de toxicidad.Exposure to lead is a

Estudio de la evolución de la exposición a plomo en la población infantil española en los últimos 20 años: ¿Un ejemplo no reconocido de «salud en todas las políticas»? Trend in lead exposure in the Spanish child population in the last 20 years: An unrecognized example of health in all policies?

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Sabrina Llop

2013-04-01

Full Text Available Objetivo: Describir la evolución temporal de las concentraciones de plomo en el aire en España, desde antes de su prohibición como aditivo de la gasolina hasta la actualidad, así como estudiar la evolución de la carga corporal de plomo en la población infantil española. Métodos: Se obtuvieron las concentraciones medias anuales de plomo en el aire en diversas ciudades españolas, desde la década de 1980 hasta la actualidad. Se realizó una búsqueda bibliográfica con el fin de identificar estudios publicados sobre concentraciones de plomo en la población infantil española. Resultados: En general se observó una disminución de las concentraciones de plomo, de mayor magnitud entre 1991 y 1999. Esta evolución decreciente se asocia con una disminución de las concentraciones de plomo en la población infantil española, desde 1989 (año en que se publica el primer estudio sobre exposición infantil al plomo hasta hoy. La disminución, tanto en el aire como en la población infantil, es muy probable que sea consecuencia de las medidas legislativas que han regulado la cantidad máxima de plomo en la gasolina, desde 1987 hasta su prohibición total en agosto de 2001. Conclusiones: Desde el punto de vista de la salud pública, la prohibición del uso de gasolina con plomo fue una acción que aumentó la protección de la salud de la población española.Objective: To describe the time trend in atmospheric lead concentrations in Spain, from before lead was banned as a gasoline additive to the present, and to determine the trend in lead body burden in the Spanish child population. Methods: We obtained the annual average for atmospheric lead levels in several Spanish cities from the 1980s to the present. A literature search was conducted to identify published studies on lead concentrations in populations of Spanish children. Results: Overall, atmospheric lead levels decreased, particularly between 1991 and 1999. This downward trend was related

El plomo español a comienzos del siglo xx: un análisis de competitividad a partir de los informes del Crédit Lyonnais

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Escudero, Antonio; Sánchez Picón, Andrés

2018-01-01

La documentación que hemos descubierto en el archivo histórico del Crédit Lyonnais de París posibilita estimar los costes de las fábricas españolas de plomo a principios del siglo xx, lo que permite profundizar en el éxito de Peñarroya y en el declive de los distritos de la Sierra de Cartagena y Linares. Esa misma documentación posee además un valor añadido, ya que informa sobre las razones por las que sobrevivían las fundiciones de los viejos distritos: altos precios del plomo metal en Londr...

Efectos en la calidad espermática del ciervo de la exposición a plomo y otros metales pesados: aplicación de modelos de exposición in vitro con espermatozoides.

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Castellanos Expósito, Pilar

2016-01-01

El plomo (Pb) uno de los tóxicos ambientales e industriales más difundidos en el planeta debido al uso con muy variados fines que se ha hecho de este metal por diferentes civilizaciones a lo largo de la historia, lo que explica la intensa actividad de extracción minera de Pb que se ha tenido que asegurar cantidades suficientes de este metal. En lo que a nuestro país se refiere, la comarca minera del Valle de Alcudia y Sierra Madrona durante los siglos XX y XX se encontraba a la cabeza de pr...

Correlación de protoporfirina zinc y plomo en sangre en trabajadores de fábricas de baterías, de Bogotá, Colombia

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Cárdenas-Bustamante Omayda

2001-01-01

Full Text Available Objetivo. Determinar la utilidad de la protoporfirina zinc en sangre (PPz como indicador de exposición a plomo en trabajadores de fábricas de baterías. Material y métodos. Se hizo un estudio transversal en 116 trabajadores de fábricas de baterías del sector informal en Bogotá, Colombia. La información sobre variables generales, ocupacionales y de salud fue obtenida por medio de una entrevista con los trabajadores. Se establecieron dos categorías para los valores de PPz: aquellos por debajo del valor límite de (70 µg/dl, y aquellos por arriba de este valor. Se empleó análisis de regresión lineal para medir la correlación entre los valores logarítmicos de PPz (>70 µg/dl y plomo en sangre (PbS (>38 µg/dl. Resultados. Se encontró un coeficiente de correlación semilogarítmica r=0.54, además de posibles asociaciones estadísticamente significativas entre los niveles elevados de PPz y el oficio actual de exposición directa (RM:3.35, IC 95% 1.02-11.91; p:0.02, emplear plomo como materia prima (RM:7.80, IC 95% 2.96-21.03; phttp://www.insp.mx/salud/index.html

FITOEXTRACCIÓN DE PLOMO Y CADMIO EN SUELOS CONTAMINADOS USANDO QUELITE (Amaranthus hybridus L. Y MICORRIZAS

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H. G. Ortiz-Cano

2009-01-01

Full Text Available Las actividades mineras y metalúrgicas practicadas en la Comarca Lagunera, México han contaminado el suelo, el aire y el agua. El uso de plantas es una de las estrategias para la remediación de suelos contaminados con metales pesados. Sin embargo, son pocos los estudios sobre remediación con plantas de zonas áridas y su asociación con micorrizas. El objetivo de este estudio fue evaluar la capacidad extractora de Plomo (Pb y Cadmio (Cd del quelite (Amaranthus hybridus L. al adicionar una mezcla de micorrizas arbusculares (Entrophospora columbiana, Glomus intraradices, G. etunicatum, G clarum al sustrato contaminado con Pb o Cd. Dos experimentos, uno por cada metal, con diseño experimental de bloques al azar con cuatro repeticiones fueron desarrollados. En el primero se adicionaron tres cantidades de micorrizas (0, 2.5 y 5.0 g·kg-1 en suelos con 300 mg·kg-1 de Pb. En el segundo experimento, las mismas cantidades de micorrizas fueron probadas en suelos contaminados con 15 mg·kg-1 de Cd. Las concentraciones de Pb y Cd en raíz, hoja y tallo a los 65, 95 y 125 días de edad de la planta se determinaron con un espectrofotómetro de absorción atómica. Los resultados indican que la adición de micorrizas incrementó significativamente (P<0.05 la concentración de Pb y Cd en raíz, tallo y hoja de quelite. Las concentraciones de estos metales se incrementaron significativamente conforme la edad de la planta.

Investigación epidemiológica sobre niveles de plomo en la población infantil y en el medio ambiente domiciliario de Ciudad Juárez, Chihuahua, en relación con una fundición de El Paso, Texas Epidemiologic study of lead levels in children and in the household environment in Ciudad Juárez, Chihuahua, México, and an area near a foundry in El Paso, Texas, USA

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Blanca Raquel Ordóñez

2003-01-01

Full Text Available Se estudió una muestra representativa de los hogares de Ciudad Juárez y el 100% de los situados al noroeste de esa ciudad, cercanos a la fundición de El Paso, Texas, a determinar niveles de plomo en sangre por lo menos un niño de 1 a 9 años de edad de cada hogar, así como el plomo del polvo intradomiciliario y de la tierra de patios, jardines de la misma casa. Se estudió riesgo ocupacional y el de ingestión de plomo por uso de loza. Se encontró que los niveles de plomo en sangre eran mayores en los niños cuyos hogares se encontraban más próximos a la fundición. Hubo una correlación positiva entre niveles de plomo en sangre y el contenido del metal en el polvo intradomiciliario y en la tierra de sus patios o jardines, estos hechos no influyeron el riesgo ocupacional ni el uso de utensilios de loza que desprendieran plomo.A representative overall sampling of households in Ciudad Juárez, plus 100 per cent of the households in an area northwest of that city near a foundry in El Paso, Texas, were studied to determine the bloodlead level of at least one child within the 1-to-9 year age range in each home and the lead content of the dust inside the house and the dirt on its yard or grounds. The occupational risk was studied, as was the risk of lead intake from food prepared in enamel cooking utensils. Bloodlead levels were found to be highest in children whose homes were closest to the foundry. There was a positive correlation between bloodlead levels and the lead content of the dust in the home and the dirt in its yard or grounds. No association was established between the higher lead levels and occupational hazards or the use of enamel cooking utensils that give of lead.

MODELO CONCEPTUAL DE RIESGO AMBIENTAL POR ARSÉNICO Y PLOMO EN EL DISTRITO MINERO DE SANTA MARÍA DE LA PAZ, SAN LUIS POTOSÍ, MÉXICO

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Carlos Chávez T.

2011-01-01

Full Text Available Con el fin de caracterizar el riesgo ambiental de un sitio contaminado en México, que se localizaen un distrito minero del estado de San Luis Potosí, se construyó su modelo conceptual. El sitio presenta niveles altos de plomo y arsénico en medios ambientales por la dispersión ambiental de residuos y emisiones de la actividad minera histórica y del presente. En la elaboración del modelo, se utilizaron procedimientos sistemáticos aprobados por la normatividad internacional e información histórica del sitio sobre contaminación, impacto y riesgo ambiental para el periodo 1995-2008. El modelo sirvió para 1 establecer conexiones Fuente-Ruta-Receptor, 2 detectar zonas donde ocurren rutas completas de exposición al arsénico y al plomo, y 3 confirmar zonas de mayor riesgo susceptibles de aplicar criterios de remediación de suelos contaminados conforme a la normatividad mexicana. Según indica el estudio, la zona de mayor potencial de riesgo corresponde a la nombrada como Villa de la Paz, destacando al arsénico como el problema principal. Modelos conceptuales en sitios mineros contaminados de EE.UU., Portugal, Irlanda y Australia han servido como herramientas para describir fuentes potenciales, rutas y posibles receptores, realizar el proceso de evaluación de riesgo, y para evaluar la factibilidad de remediación del sitio, entre otros. La normatividad mexicana recomienda elaborar el modelo conceptual en estudios de evaluación de riesgo ambiental y para la remediación del sitio. No obstante, no existen casos documentados en revistas científicas sobre la construcción de estos modelos en sitios mineros de México. Uno de los beneficios potenciales del uso del modelo propuesto, es que, una vez que ha sido simplificada la información, puede ser una herramienta básica para el desarrollo de evaluaciones ambientales del sitio estudiado y una guía para la construcción de modelos en otros sitios mineros de México.

REMOCIÓN DE PLOMO EN AGUA A PARTIR DE MATERIAL NANOESTRUCTURADO, NANOTUBOS DE CARBONO SOPORTADOS EN ZEOLITA NATURAL

Directory of Open Access Journals (Sweden)

Holanda I. Cruz

2017-01-01

Full Text Available En este trabajo se realizó la cinética de remoción de plomo en agua con un material nanoestructurado, nanotubos de carbono soportados en zeolita (NTC-ZN, y con zeolita natural (ZN. La zeolita utilizada proviene de los Valles Centrales de Oaxaca, México. El material nanoestructurado se sintetizó por el método de aspersión pirolítica bajo condiciones especificas; se caracterizó por microscopía electrónica de barrido y de transmisión (SEM y TEM y determinación de área superficial (BET. Los materiales se probaron con una solución de plomo a una concentración de 10 ppm bajo condiciones de agitación y filtrado a vacío. El filtrado se caracterizó por espectrometría de masas con plasma acoplado inductivamente (ICP-MS. Los porcentajes de remoción fueron de 99.96% para NTC-ZN y 99.27% para la zeolita natural en 120 minutos. Sin embargo un 94.5% de remoción se presenta en un tiempo 6 veces menor con el híbrido que con ZN.

Exposición a plomo en niños de 6 a 12 años de edad Lead exposure in children from 6 to 12 years old

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Carlos Jiménez-Gutiérrez

1999-11-01

Full Text Available Objetivo. Identificar los factores de exposición asociados a las concentraciones de plomo en niños de escuelas primarias públicas y privadas de la ciudad de México. Material y métodos. Se realizó un estudio transversal en 340 niños que asistían a la escuela primaria. Las escuelas se seleccionaron por conveniencia y los niños en forma aleatoria. Se aplicó un cuestionario y se tomaron muestras de sangre venosa. Los niveles de plomo se determinaron por espectrofotometría de absorción atómica. Se compararon medias mediante la prueba t de Student-Fisher y ANDEVA; y para el análisis multivariado, regresión lineal múltiple. Debido a que los niveles de plomo no seguían una distribución normal, se transformó con logaritmo neperiano, con la que se trabajó en todo el análisis estadístico. Resultados. Las medias geométricas para escuelas privadas y públicas fueron: MG=8.76 µg/dl, IC95%=9.1-10.5; MG=11.5 µg/dl, IC95%=9.4-13.5, respectivamente. Los niveles de plomo son más elevados en los niños que asisten a la escuela pública y que presentan las siguientes características: ser varones, tener entre seis y ocho años de edad y cursar el primer o segundo grado de primaria; las madres de estos niños son profesionistas; en sus hogares se utiliza la cerámica vidriada y cerca de sus domicilios existen diferentes tipos de talleres contaminantes con plomo. Conclusiones. Los factores de exposición que predicen las concentraciones de plomo en sangre son: tener entre seis y ocho años de edad, la ocupación de la madre, la utilización de cerámica vidriada, la cercanía de diferentes tipos de talleres contaminantes con plomo a los domicilios y cursar el segundo año de primaria.Objective. To identify exposure factors contributing to lead poisoning in school children from Mexico City. Material and methods. Cross-sectional study of 340 children. A convenience sample of schools and a random sample of children were selected. A questionnaire

Estudio sobre la incorporación y retención de plomo en zeolita natural

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Abraham Mendoza Córdoba

2014-12-01

Full Text Available Las zeolitas son un grupo de minerales que corresponden a la clase de los silicatos (tectosilicatos, entre las diversas utilidades que tienen estos minerales está la resolución de problemas ambientales, particularmente en la eliminación de contaminantes, entre estos se encuentran los metales pesados, los cuales están presentes en los suelos de zonas industriales, en el agua potable, en los afluentes de aguas procedentes de la industria y de la actividad minera, o bien procedentes de mantos acuíferos. Su utilidad se debe en parte por tener una gran capacidad de intercambio iónico, así como también por tener una estructura con cavidades de dimensiones nanométricas, eso le da la capacidad de incorporar elementos ajenos al mineral dentro de dichas cavidades. En el presente trabajo se ha experimentado con Pb incorporándolo en zeolitas (chabazita como acetato de plomo (Pb(CH3COO2 3H2O con el fin de conocer, por una parte, la capacidad del mineral para alojar dicho metal después de activarla, y por otra parte, conocer la capacidad de retención del metal después de un proceso reversible a la incorporación de Pb (activación.

Contenido de plomo y cadmio en aceites de girasol

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López Martínez, M. C.

2001-08-01

Full Text Available We have studied the lead and cadmium content in 21 samples of sunflower oil from Andalucía (Southern Spain. These elements are toxicological importance and the sunflower oil is widely consumed in Spain. Samples were mineralized with nitric acid and vanadium pentoxide as catalyst, and ana lyzed using electrothermal atomization atomic absorption spectroscopy. The temperature-time programme for the graphite furnace was optimized for each element, and the accuracy, precision, sensitivity and detection limit of the method were evaluated. Concentrations of lead ranged from not detectable to 167.58 μg/kg and cadmium concentrations ranged from 0.87 to 8.30 μg/kg. The data obtained are not excessive and similar to those mentioned by other authors; however, one sample of the total analyzed surpassed the limit of 0.1 ppm of lead proposed by the Spanish and European Legislation. A statistical significative correlation has been established between Pb and Cd levels (p Se ha determinado el contenido de plomo y cadmio en 21 muestras de aceite de girasol, todas ellas producidas en Andalucía (Sur de España. Ambos elementos tienen una gran importancia toxicológica y el aceite de girasol es muy consumido en España. Las muestras han sido mineralizadas con ácido nítrico, utilizando pentóxido de vanadio como catalizador, y analizadas mediante espectroscopia de absorción atómica con atomización electrotérmica. Se ha optimizado el programa temperatura-tiempo del horno de grafito para cada elemento y se ha evaluado la exactitud, precisión, sensibilidad y límite de detección del método. Las concentraciones de plomo han oscilado entre no detectables y 167.58 μg/kg y las concentraciones de cadmio entre 0.87 y 8.30 μg/kg. Estos datos no resultan excesivos y concuerdan con los aportados por otros autores; no obstante, una de las muestras analizadas supera el límite máximo de 0.1 ppm de Pb establecido en las Legislaciones Española y Europea. Se

Benefits and costs of alcoholic relationships and recovery through Al-Anon.

Science.gov (United States)

Young, Lance Brendan; Timko, Christine

2015-01-01

Codependence is an ambiguous and disputed term often used to characterize both those who maintain relationships with alcoholics and those who seek help through resources such as Al-Anon Family Groups. The purpose of this article is to better understand non-pathological reasons for maintaining alcoholic relationships and for help-seeking by detailing the costs and benefits of those choices. The costs and benefits both of remaining in an alcoholic relationship and of seeking help in Al-Anon were identified through a review of available research on alcoholic family systems, Al-Anon, and other mutual-support groups. Alcoholic relationships may benefit concerned others by preserving self-identity, social identity, values, security, stability, and hope. Costs of alcoholic relationships include physical symptoms, injury, mental problems, financial difficulty, legal troubles, and relational distress. Al-Anon is perceived beneficial for six primary reasons: Al-Anon philosophy, format, social support, accessibility, effectiveness, and potential to change the drinker's behavior. Possible costs of Al-Anon include marginalization of the concerned other, blame, codependent pathology, sexist stereotyping, substitute dependency, and perpetuating victimization. Conclusions/Importance: The identified costs and benefits of alcoholic relationships and help-seeking in Al-Anon can help to model decision-making processes using existing behavioral health frameworks without defaulting to the stigmatized and ambiguous codependence terminology.

Tratamientos postfermentativos del vinagre: conservación en botella, envejecimiento acelerado y eliminación del plomo

OpenAIRE

Labbé Pino, Mariela Alejandra

2007-01-01

La presente investigación se ha dividido en tres temas, el primero de ellos ha estudiado los efectos de diferentes condiciones de almacenamiento sobre las características de vinagres comerciales. El segundo, ha estudiado el envejecimiento de vinagres con virutas de roble. Finalmente, se ha estudiado la reducción de plomo en vinagres a nivel trazas mediante el uso de una resina de intercambio catiónico. En el estudio de conservación, se han empleado vinagres de manzana y de vino chardonnay, ca...

Factores asociados al estado de salud de adolescentes con exposición continua a plomo, arsénico y flúor, que viven cerca de una zona metalúrgica en la ciudad de San Luis Potosí

OpenAIRE

Cossío Torres, Patricia Elizabeth

2011-01-01

identificar los factores individuales, familiares, sociales y de exposición a agentes contaminantes; que intervienen en el estado de salud actual (nutricional, cognitivo, salud mental y rendimiento escolar) y conductas de riesgo para la salud (agresión/delincuencia, consumo riesgoso y dañino de alcohol, consumo de tabaco y uso/abuso de sustancias) de un grupo de adolescentes expuestos crónicamente a plomo, arsénico y flúor. Tesis de Posgrado de la Universidad Autonoma de San Luis Pot...

Determinants of blood-lead levels in children in Callao and Lima metropolitan area Determinación de los niveles de plomo en sangre de niños de El Callao y del área metropolitana de Lima

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Rocío Espinoza

2003-01-01

. En esta zona se detectó un área de almacenamiento de minerales como una fuente importante de exposición. Los niños que viven cerca de esta área tenían en promedio un exceso de 13 µg/dl en sangre. Para los participantes de la zona de Lima el riesgo de presentar niveles por encima de 10 µg/dl se asoció con la exposición a tráfico vehicular. CONCLUSIONES: Para Lima Metropolitana se puede concluir que los niveles de plomo en sangre no representan un problema urgente, sin embargo, el reducir el plomo de la gasolina se acompaña de un beneficio importante. En contraste, para el área cercana al puerto de El Callao, nuestro estudio demuestra la presencia de sitios de almacenamiento de minerales que representan un riesgo importante para la salud de los niños que viven en esta zona.

Adsorción de plomo y cadmio en sistema continuo de lecho fijo sobre residuos de cacao

OpenAIRE

Jose Lara; Candelaria Tejada; Angel Villabona; Alfonso Arrieta; Clemente Granados Conde

2016-01-01

Se evaluó el desempeño de la cáscara de cacao como material residual adsorbente de metales pesados (Plomo y Cadmio) en solución acuosa sintética, mediante un sistema continuo de lecho fijo. El trabajo experimental consistió en determinar el efecto de la altura del lecho en la remoción de estos contaminantes, manteniendo constantes parámetros como el pH, velocidad de flujo y concentración inicial de los metales. Las pruebas de adsorción presentaron una remoción de 91,32 y 87,80%...

Fracciones biodisponibles de arsénico, plomo, cadmio y mercurio en sedimentos de corrientes superficiales seleccionadas

OpenAIRE

Hernández Peñalver, María Teresa; García Melián, Maricel; Cañas Pérez, Regla; Sardiñas Peña, Olivia

1999-01-01

Se realizó la determinación de las fracciones biodisponibles de arsénico, cadmio, plomo y mercurio en los sedimentos de 10 ríos seleccionados, los cuales abastecen a comunidades de más de 5 000 habitantes en Cuba. Se efectuó la extracción en la fracción compuesta por partículas menores de 63 mym, con ácido clorhídrico 0,5 mol/L. En los casos de arsénico y cadmio, todas las muestras presentaron niveles inferiores a los límites de cuantificación de los métodos de ensayo. Las medianas de las con...

Humoral immune alterations caused by lead: studies on an adult toad model Alteraciones inmunes humorales causadas por plomo: estudios en un modelo de sapo adulto

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Carolina E. Rosenberg

2007-07-01

(heteroaglutininas naturales fueron también cuantificados contra EO. Ambas evaluaciones fueron llevadas a cabo empleando un método de ELISA desarrollado a este fin, midiendo la absorbancia (A. Para los anticuerpos anti-EO naturales, tanto en sapos controles (C como en sapos tratados con Pb (T, hubo una tendencia significativa a incrementar las absorbancias iniciales (C inicial: 0,69±0,39 A; T inicial: 0,54±0,30 A; la relación T/C tampoco mostró cambios. La única diferencia significativa se encontró entre las muestras inicial y final de los sapos tratados con plomo (p<0,014. Los niveles de anticuerpos anti-EO inmune de sapos inmunizados con EO mostraron un bajo incremento significativo (p<0,05 en los animales tratados con plomo (T final: 0,66±0,36 A, al compararse con sapos control (C final: 0,91±0,50 A al final del experimento. De este modo, se concluye que los cambios debidos a las dosis analizadas de Pb en los niveles de anticuerpos no pueden explicarse sólo sobre la base de un único mecanismo de acción del metal, sino como resultado de una conjunción de efectos sobre diferentes subpoblaciones de células inmunocompetentes. Estas diferentes respuestas sugieren que los factores que afectan los animales expuestos a un estímulo externo son diferentes de aquellos que influyen la respuesta en los animales silvestres.

Adsorción de plomo y cadmio en sistema continuo de lecho fijo sobre residuos de cacao

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Jose Lara

2016-12-01

Full Text Available Se evaluó el desempeño de la cáscara de cacao como material residual adsorbente de metales pesados (Plomo y Cadmio en solución acuosa sintética, mediante un sistema continuo de lecho fijo. El trabajo experimental consistió en determinar el efecto de la altura del lecho en la remoción de estos contaminantes, manteniendo constantes parámetros como el pH, velocidad de flujo y concentración inicial de los metales. Las pruebas de adsorción presentaron una remoción de 91,32 y 87,80% respectivamente para Pb y Cd después de transcurridos 4,5 h La medición de las concentraciones en solución acuosa de los iones metálicos se hizo por adsorción atómica. Se evaluó el ajuste de los modelos matemáticos de Thomas, Dosis-Respuesta, Adams-Bohart y BDST (Bed-Depht Service Time analysis, para predecir el comportamiento dinámico de la columna y obtener los parámetros cinéticos correspondientes. Para los modelos de Thomas y de Dosis-Respuesta, se observó que los valores de la capacidad inicial de adsorción, q0, disminuyeron al aumentar la altura del lecho, esto pudo deberse a una transferencia de masa más lenta, concentración más baja y aumento dela capacidad de adsorción, mientras que los modelos de Adams-Bohart y BDST, la capacidad de adsorción volumétrica, N0, decrece al aumentar el bioadsorbente en la columna. Los resultados presentados en este estudio indican que los residuos de cacao pueden ser usados para la remoción de metales pesados presentes en aguas residuales satisfactoriamente.

Awortwi et al.: Mixing and stratification relationship on phytoplankton ...

African Journals Online (AJOL)

Awortwi et al.: Mixing and stratification relationship on phytoplankton of Lake Bosomtwe (Ghana) 43 West African Journal of Applied Ecology, vol. 23(2), 2015: 43–62. The Relationship Between Mixing and Stratification Regime on the Phytoplankton of Lake Bo.

Niveles de plomo y cadmio en agua marina y lapas (Patella vulgata L.) de la Ría de Vigo

OpenAIRE

M. Pérez López; M.C Nóvoa; J. Alonso; M. A. García Fernández; M.J. Melgar

2003-01-01

El empleo de seres vivos para monitorizar la contaminación por metales pesados en los ecosistemas acuáticos es de extremo interés en el campo de la ecotoxicología. En el presente estudio se han recogido muestras de agua marina y de lapas (Patella vulgata L.) de distintos puntos de la Ría de Vigo, con la intención de determinar en ellos los niveles de plomo y cadmio, por medio de una técnica de voltamperometría. Los resultados obtenidos mostraron una relación estrecha entr...

Fricción interna en plomo de muy alta pureza (99,9999% a temperaturas medias

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Gallego, I.

2001-04-01

Full Text Available Internal friction spectra of high purity lead (99.9999% at medium temperatures exhibit a main relaxation peak at 230 K (P₁ which depends strongly on the dislocation arrangement. The mechanism associated to P₁ relaxation has an activation area between 500b² and 2000b² and its activation energy is 0.65±0.05 eV (63±5 KJ/mol, which is only 0,6 times the autodiffusion energy of lead. The behaviour of P₁ peak and its dependence on thermomechanical treatments has allowed us to conclude that it is associated to the sliding of dislocations controlled by the climbing of jogs by diffusion of vacancies along the dislocation lines. At a slightly higher temperature, another relaxation (P₁ turns up in the spectra, which can be associated to different mechanisms.

El espectro de fricción interna, a medias temperaturas, del plomo de muy alta pureza (99,9999% presenta una relajación principal a 230 K (P₁, cuya intensidad depende fuertemente del estado de organización de las dislocaciones. La medida de los parámetros de activación de P₁ indica que el mecanismo asociado a esta relajación tiene un área de activación comprendida entre 500b² y 2.000b² y un valor de la energía de activación de 0,65 ±0,05 eV (63±5 KJ/mol, que es sólo 0,6 veces la energía de autodifusión del plomo. El comportamiento de esta relajación y su dependencia con los tratamientos termomecánicos, nos ha permitido concluir que P₁ está originado por el deslizamiento de dislocaciones controlado por la escalada de escalones a lo largo de la línea de dislocación. A temperaturas ligeramente superiores, aparece otra relajación (P₁, cuyo origen puede estar ligado a diferentes mecanismos.

Determinación de los niveles de plomo y cadmio en leche procesada en la ciudad de Bogotá D.C.

OpenAIRE

Pinzon Choque, Carlos Giovanni

2015-01-01

La leche y los productos lácteos han sido reconocidos en todo el mundo por su influencia beneficiosa sobre la salud humana. Los niveles de metales en concentraciones tóxicas son un componente importante de la seguridad y la calidad de la leche. Se desarrolló un método sencillo de extracción (digestión) asistida por microondas para la determinación posterior de los niveles de cadmio (Cd) y plomo (Pb) en leche líquida por espectrofotometría de absorción atómica (AAE) con horno de grafito. Se ap...

Bioadsorción de iones de plomo y cromo procedentes de aguas residuales utilizando la cáscara de la mandarina (Citrus Reticuata Var. Clementina)

OpenAIRE

Verdugo Vergara, José Francisco

2017-01-01

El presente trabajo tiene el objetivo de evaluar la capacidad de bioadsorción de plomo y cromo mediante la cáscara de la mandarina, la cual es considerada un residuo, con esta investigación lo que se desea es aprovechar este residuo, empleándolo como bioadsorbente en el tratamiento de las aguas residuales contaminadas con metales pesados. En los procesos de bioadsorción se variaron algunos parámetros. The objective of this work assignment is to evaluate the bioadsorption capacity of lead a...

Niveles de plomo en gestantes y neonatos en la ciudad de la Oroya, Perú

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Jorge Castro-Bedriñana

Full Text Available Objetivos. Determinar los niveles de plomo (Pb en gestantes y neonatos en la ciudad de La Oroya, Perú. Materiales y métodos. Se realizó un estudio transversal. La población estuvo conformada por gestantes residentes durante al menos dos años en la ciudad de La Oroya, cuando operaban normalmente las fundiciones de Pb, cobre y zinc. Se obtuvo muestras de sangre de la gestante antes del parto y luego del parto se tomaron muestras de placenta y sangre del cordón umbilical. El nivel de Pb de dichas muestras fue evaluado por espectrometría de absorción atómica con horno de grafito. Se determinaron regresiones cuadráticas y correlaciones de Pearson. Resultados. Se evaluó cuarenta partos normales. Los niveles promedio de Pb en la sangre materna, cordon umbilical y placenta fueron 27,4 ± 15,6 ug/dL; 19,0 ± 12,6 ug/dL y 319,0 ± 215,9 ug/100 g, respectivamente. El 67,5% de los neonatos tuvieron más de 10 ug/dL de Pb. El nivel de Pb de la sangre del cordón umbilical representó el 69,4% del nivel de Pb en sangre materna. Los coeficientes de correlación entre el Pb de la sangre materna y cordón umbilical, sangre materna y placenta, placenta y sangre del cordón umbilical fueron 0,36; 0,48 y 0,33, respectivamente. Conclusiones. Cuando funcionaba la fundición, las gestantes y recién nacidos tenían concentraciones elevadas de Pb en sangre. Las concentraciones de Pb en la placenta y cordón umbilical tuvieron una correlación moderada con el Pb de la sangre materna. El Pb de la sangre materna y cordón umbilical fue 1,5 veces más alto que los de zonas más alejadas

Communication: a relationship between hardness and flow stress of ordered Zr3Al polycrystals

International Nuclear Information System (INIS)

Schulson, E.M.; Roy, J.A.

1977-01-01

The purpose of this note is to describe a relationship between hardness and flow stress for the ordered L1$sub 2$ phase Zr$sub 3$Al, a possible structural material for use in nuclear power reactors. Experimental data obtained with the Zr-8.9% Al alloy lead to the conclusion that the hardness of polycrystalline Zr$sub 3$Al obeys an expression of the Hall-Petch form. When combined with a similar expression for flow stress, established previously, a simple relationship is obtained for flow stress in terms of hardness of well annealed material. Hardness measurements thus provide a rapid and inexpensive assessment of the strength of Zr$sub 3$Al. 8 refs

Estudio experimental de la adhesión interfacial del sistema Sn/Pb - Al2O3 asistido con láser

OpenAIRE

Guerrero, A; Puerta, J; Lira, J

2006-01-01

En el presente trabajo se propuso y construyó un diseño de cámara de experimentación que permitió realizar diferentes mediciones del ángulo de contacto. El substrato cerámico (Sn/Pb - Al2O3) fue previamente tratado con un láser de CO2 y sobre el mismo se depositó una aleación de Estaño-Plomo fundido empleando el método de la gota en reposo en alto vacío. Estas mediciones experimentales se realizaron con el fin de conocer el comportamiento físico-químico de la mojabilidad del sistema metal-cer...

Cuantificación de plomo, cadmio y cromo mediante sialoquímica Quantification of lead, cadmium and chromium through sialochemistry

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MIREYA GONZÁLEZ

1997-05-01

Full Text Available Objetivo. Determinar las concentraciones de plomo, cadmio y cromo, y establecer su posible asociación con diferentes factores sociodemográficos. Material y métodos. Se seleccionó una muestra representativa de 100 estudiantes de posgrado de la Facultad de Odontología de la Universidad Nacional Autónoma de México (UNAM, a los cuales se les colectó saliva total no estimulada. Dichas muestras fueron analizadas por espectrofotometría de absorción atómica con horno de grafito. Resultados. Metales pesados como el plomo, el cadmio y el cromo se encuentran en concentraciones mucho más altas que las informadas en la literatura: Pb, = 3.10 m g/dL-1, máxima: 16.8 my g/dL-1, y mínima: 0.04 my g/dL-1; Cd, = 0.25 my g/dL-1, máxima: 2.04 my g/dL-1, y mínima: 0.004 my g/dL-1; y Cr, = 1.43 my g/dL-1, máxima: 4.82 my g/dL-1, y mínima: 0.05 my g/dL-1. Asimismo, variables como la zona de residencia, el sexo, la edad y la ingesta de comida enlatada no influyen en los niveles de plomo y cromo. Sin embargo, en el caso del cadmio y la edad existe una asociación inversa (ji²= 5.9012, pObjective. To determine the concentration of lead (Pb, cadmium (Cd, and chromium (Cr and establish the possible association of these heavy metals with some sociodemographic factors. Material and methods. A representative sample of one hundred dental students from the National Autonomous University of Mexico living in Mexico City participated in this study. Unstimulated human whole saliva samples were analyzed by Atomic Absorption Spectroscopy. Results. Concentrations of Pb, Cd, and Cr were higher than those reported elsewhere: Pb ( or = 3.10 m g/dL-1; Maximum: 16.8 mu g/dL-1 and Minimum: 0.04 mu g/dL-1, Cd ( or = 0.25 mu g/dL-1; Maximum: 2.04 mu g/dL-1 and Minimum: 0.004 mu g/dL-1 and Cr ( or = 1.43 mu g/dL-1; Maximum: 4.82 mu g/dL-1 and Minimum: 0.05 mu g/dL-1. No association was found between the variables studied (age, sex, geographic area and canned food consumption

Temporal trending of lead and cadmium contamination in the Vigo estuary intertidal area Evolución temporal de la contaminación por plomo y cadmio en la zona intermareal de la ría de Vigo

Directory of Open Access Journals (Sweden)

J. Alonso Díaz

2004-12-01

Full Text Available At the present work, limpet (Patella vulgata L. and seaweed (Ulva lactuca specimens have been monthly sampled at the same point from the Vigo estuary, during a year. Heavy metal (cadmium and lead content has been determined by means of differential pulse anodic stripping voltammetry in both limpet and seaweed tissues, as well as in seawater. The obtained results have shown the main heavy metal content in limpet soft tissues with respect to shell, with maximum concentrations of 3 ppm (limpet shell for lead, whereas the highest content for cadmium was identified in seaweed samples (1.1 ppm. The statistical study revealed the existence of a clear correlation between cadmium and lead concentrations in seaweed samples.En el presente trabajo se han recogido muestras de lapa (Patella vulgata L. y alga verde (Ulva lactuca en un mismo punto de muestreo de la ría de Vigo, con una periodicidad mensual, a lo largo de un año, analizándose por medio de voltamperometría de redisolución anódica la concentración en dos metales pesados con claras repercusiones toxicológicas, cadmio y plomo, en estas muestras, así como en el agua marina. Los resultados obtenidos mostraron la mayor concentración de ambos metales en los tejidos blandos de las lapas frente a las valvas de estos moluscos, con valores máximos en el caso del plomo próximos a 3 ppm (valva de lapa, mientras que para el cadmio se situó en torno a 1,1 ppm (alga verde. El estudio estadístico permitió poner en evidencia una clara correlación estadística entre los valores de cadmio y plomo cuantificados en las muestras de algas.

Intervención ambiental en sitios contaminados por plomo: la experiencia en los Estados Unidos de América Environmental intervention in sites contaminated by lead: the United States of America experience

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Nicholas Ceto

2003-01-01

Full Text Available Durante una década, los organismos estatales y federales han trabajado de manera conjunta con las comunidades a lo largo del territorio estadounidense, con el objeto de valorar el riesgo a la salud que implica la contaminación por plomo en las zonas residenciales. A menudo dichas comunidades han estado vinculadas con instalaciones destinadas anteriormente a actividades como la minería y la metalurgia; sin embargo, existen otras industrias como por ejemplo la fabricación de pinturas y el reciclaje de baterías, también identificadas como fuentes de contaminación por este metal. La vasta experiencia en las tareas de limpieza de los sitios contaminados ha puesto de manifiesto que los amplios programas destinados a identificar y manejar las vías de exposición pueden ayudar, de manera efectiva, a disminuir los niveles de plomo en sangre de las poblaciones más suceptibles, como la de los de niños en edades tempranas. Los programas de intervención ambiental son más efectivos cuando en las localidades afectadas se ejecutan programas de educación/intervención en salud, orientados al desarrollo de estrategias individualizadas para manejar el riesgo que implica la presencia de dicho metal en el ambiente.For a decade, state and federal agencies have worked jointly with communities throughout the USA, with the objective of measuring the health-risk from lead pollution in residential zones. Often these communities have been linked with facilities previously associated with activities like mining and metallurgy; nevertheless, there are other industries like paint manufacturing and battery recycling, that have also been identified as lead pollution sources. The vast experience in cleaning up the contaminated sites has shown that ample programs designed to identify and handle the exposure routes can help, in an effective manner, to diminish blood lead levels (BLL in susceptible populations, such as in young children. Environmental intervention

Validation of the methodology for the quantitative determination of lead in cosmetics dyes available in the national market by atomic absorption spectroscopy with flame; Validacion de la metodologia para la determinacion cuantitativa de plomo en tintes cosmeticos disponibles en el mercado nacional por espectroscopia de absorcion atomica con llama

Energy Technology Data Exchange (ETDEWEB)

Silva Trejos, Paulina [Univ. de Costa Rica, Escuela de Quimica, telefono 2511-4870, fax 2253-5020 (Costa Rica)], E-mail: stpaulinita@gmail.com

2008-07-15

The analytical methodology was validated to quantify lead in cosmetics dyes available on the national market, by the method of atomic absorption spectroscopy with flame. The samples were digested by wet digestion with HNO{sub 3} to 65% m/m in a microwave oven, the percentage of recovery for the digestion of samples of 0,25 g and 0,45 g in 5,00 mL was of 100,5{+-}0,5. The field of optimal linearity detection limit was 5,0 mg/L with a correlation coefficient of 0,9998. The limits of detection and quantification limits determined graphically by the method of row errors for linear regression of 0,12{+-}0,02 mg/L and 0,21{+-}0,02 mg/L, respectively. Precision was evaluated determining the repeatability as standard deviation of five replicas of a positive dye for lead, according to the definition of the ISO, 2{radical}2*, and obtained a value of 2,3. The veracity was determined through percentages of recovery assessed, adding aliquots of lead patterns to dye samples and compared with the same mass to which they are not make additions. The dye samples were obtained at point of sale, such as pharmacies, beauty suppliers, supermarkets, sales of natural products and the central market of San Jose. The dyes tested contain lead acetates active ingredient, these are: Doni, Mont D'Or, Matador y Siempre Joven; they are produced locally, Youthair brand and American manufacturing. (author) [Spanish] La metodologia analitica fue validada para determinar cuantitativamente el plomo en tintes cosmeticos disponibles en el mercado nacional, por el metodo de espectroscopia de absorcion atomica con llama. Las muestras se dirigieron por digestion humeda con HNO{sub 3} al 65% m/m en horno de microondas; el porcentaje de recuperacion para la digestion de muestras de 0,25 g y 0,45 g en 5,00 mL fue de 100,5{+-}0,5. El ambito de linialidad optimo fue del limite de deteccion de 5,0 mg/L con un coeficiente de correlacion de 0,9998. Los limites de deteccion y los limites de cuantificacion

The relationship between the hardness and the point-defect-density in neutron-irradiated MgO·3.0Al2O3 and AlN

International Nuclear Information System (INIS)

Suematsu, H.; Yatsui, K.; Yano, T.

2001-01-01

MgO·3.0Al 2 O 3 single crystals and sintered AlN polycrystals were irradiated with fast neutrons in various conditions and the hardness of the irradiated and unirradiated samples was measured with a Vickers hardness tester. The hardness of as-irradiated MgO·3.0Al 2 O 3 and AlN samples increased by 23 and 51%, respectively. After isochronal annealing, the hardness gradually decreased and mostly recovered to that of the unirradiated one up to 1400degC. Volume of the sample also increased after the irradiation and changed in the same way as the hardness by annealing. A relationship between the hardness and the density of point defects is proposed and the experimental results agree with the relationship. It implies that the point defects generated by the irradiation pin down dislocations and increase the hardness of neutron irradiated MgO·3.0Al 2 O 3 samples. (author)

Algunas consideraciones sobre saturnismo entre los trabajadores de una fundición

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César E Carlín

1956-07-01

Full Text Available Este estudio fué realizado en los trabajadores de una fundición que estaban expuestos, entre otros contaminantes atmosféricos, principalmente a humos de plomo. Entre 1,468 trabajadores observados, se encontró 138 casos de plumbismo, 3 de los cuales tenían sólo 30 días de trabajo. Los resultados más importantes del estudio clínico y de laboratorio en los 138 casos de plumbismo fueron: dolor abdominal (61.6%, cefalea (42.0%, debilidad (33.3%, vómitos (18.8%, ribete de Burton (56.5%, ictericia (42.0%, palidez (41.3%, hiperreflexia (21.0%, disminución de la fuerza muscular (15.9% . Del estudio comparado con un grupo patrón de 100 trabajadores no expuestos a humos de plomo y sanos al examen médico, se ha encontrado disminución significante en la hemoglobina, hematocrito, y hematíes de los individuos con plumbismo. La media aritmética de plomo en sangre total fué de 0. 162 mgrs. por 100 grs. y de 0.507 mgrs. por litro de orina, en muestras de 100 cc. Existen trabajadores intoxicados por plomo, con incapacidad potencial, desempeñando sus ocupaciones.

Relationship between the Al resistance of grasses and their adaptation to an infertile habitat.

Science.gov (United States)

Poozesh, Vahid; Cruz, Pablo; Choler, Philippe; Bertoni, Georges

2007-05-01

Original data on Al resistance, relative growth rate and leaf traits of five European grasses as well as literature data on Al resistance, habitat preference and traits of grasses were considered to determine whether (a) Al resistance is correlated to a growth conservative strategy and (b) species occurrence could be useful to assess Al toxicity in meadows on acid soils. The Al resistance of 15 species was represented by the Al activity in nutrient solution that resulted in a 50 % decrease in root length, [Al(3+)](50), or, for published values, in root or plant biomass. The correlations between Al resistance and acidity or nitrogen indices and the correlation between Al resistance and selected traits (relative growth rate, leaf dry matter content, specific leaf area and leaf thickness) were calculated. Principal component analysis was used for the characterization of the relationships between Al resistance and measured traits. The [Al(3+)](50) values of the resistant species Molinia caerulea and Sieglingia decumbens were 13 and 26 microm [Al(3+)](50), respectively. The known Al resistance of 15 species that were mainly of the intermediate strategy competitor-stress tolerator-ruderal (C-S-R) type and of the S type was correlated with Ellenberg's nitrogen and acidity indices. For the whole set of species, the correlation between Al resistance and traits was not significant. The Al resistance of the C-S-R species was variable and independent of their traits. S-type species, adapted to acid soils and with traits of conservative strategy, displayed Al resistance. The large difference in Al resistance between grasses may help assess Al soil toxicity by using the abundance of grasses.

The relationship between viscosity and refinement efficiency of pure aluminum by Al-Ti-B refiner

Energy Technology Data Exchange (ETDEWEB)

Yu Lina [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, 73 Jingshi Road, Jinan 250061 (China); Liu Xiangfa [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, 73 Jingshi Road, Jinan 250061 (China)]. E-mail: xfliu@sdu.edu.cn

2006-11-30

The relationship between viscosity and refinement efficiency of pure aluminum with the addition of Al-Ti-B master alloy was studied in this paper. The experimental results show that when the grain size of solidified sample is finer the viscosity of the melt is higher after the addition of different Al-Ti-B master alloys. This indicates that viscosity can be used to approximately estimate the refinement efficiency of Al-Ti-B refiners in production to a certain extent. The main reason was also discussed in this paper by using transmission electron microscopy (TEM) analysis and differential scanning calorimetry (DSC) experiment.

Acumulación de metales (cadmio, zinc, cobre, cromo, níquel y plomo) en especies del género Pelargonium, suministro desde el suelo, ubicación en la planta y toxicidad

OpenAIRE

Orroño, Daniela Inés

2011-01-01

La acción antrópica puede causar la contaminación de los suelos con metales. Para la remediación de pequeñas áreas contaminadas se sugirió el uso de plantas ornamentales. En esta tesis, inicialmente se estudió la capacidad de fitorremediación de tres especies del género Pelargonium en un suelo contaminado con cadmio, zinc, cobre, cromo, níquel y plomo, y se seleccionó la más tolerante (Pelargonium hortorum). Los objetivos fueron estudiar en qué fracciones químicas y físicas del suelo se ubica...

Trace elements in ALS patients and their relationships with clinical severity.

Science.gov (United States)

Oggiano, Riccardo; Solinas, Giuliana; Forte, Giovanni; Bocca, Beatrice; Farace, Cristiano; Pisano, Andrea; Sotgiu, Maria Alessandra; Clemente, Simonetta; Malaguarnera, Michele; Fois, Alessandro Giuseppe; Pirina, Pietro; Montella, Andrea; Madeddu, Roberto

2018-04-01

An exploratory study of trace elements in ALS and their relationships with clinical severity was detected. Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that causes irreversible damage in humans, with the consequent loss of function of motoneurons (MNs), with a prognosis up to 5 years after diagnosis. Except to genetic rare cases it is not known the etiology of the disorder. Aim of our research is to investigate the possible role of heavy metals in the severity of the disease. In this study, by the use of plasma mass (ICP-MS), we have analyzed the content of essential and heavy metals such: Pb, Cd, Al, Hg, Mn, Fe, Cu, Zn, Se, Mg, and Ca, in blood, urine and hair of ALS patients and controls; moreover we divided the patients in two groups for disease severity and analyzed the difference among the groups, in order to study a possible involvement of metals in the severity of the damage. Our results suggest a protective role of Selenium, involved in protective antioxidant mechanisms, and a risk factor in the case of presence of Lead in blood. The levels of the other metals are not easy to interpret, because these may be due to life style and for essential metals a consequence of the disease condition, not a cause. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microstructures and phase relationships in the Ti3Al + Nb system

International Nuclear Information System (INIS)

Kestner-Weykamp, H.T.; Kaufman, M.J.

1989-01-01

Alloys based on the α 2 -Ti 3 Al compound (hexagonal) DO 19 are currently experiencing limited use as advanced aerospace materials. To date, the alloys with the most desirable properties contain additions of β stabilizers, such as Nb, Mo and V, which promote the formation of a two-phase mixture of α 2 +β or α 2 +B2 (where B2 refers to the ordered CsCl structure). Unfortunately, the phase relationships in these systems have not been established in sufficient detail to allow their more widespread application. Recently, there has been a series of investigations aimed at alleviating this deficiency in the ternary Ti-Al-Nb system. These studies have clearly indicated the existence of the ordered B2 phase, which, in the higher Nb alloys, can be retained at room temperature by rapid cooling from the liquid or solid state. The authors describe (TiNb) 3 Al alloys (from 0 to 30 at. pct. Nb) were studies after conventional and nonequilibrium (i.e., rapid solidification) processing with an emphasis on providing further insight into the transformation sequences and phase equilibria in these alloys

Efecto del BiFeO3 en las propiedades del sistema ferroeléctrico libre de plomo K0.5Na0.5NbO3

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Pinza, Billy N.

2014-10-01

Full Text Available In order to obtain a multiferroic material, powders and ceramic pieces, of the lead-free ferroelectric (1-x-x K0.5Na0.5NbO3 (Bi0.8La0.2FeO3 (KNN-BLFO (x = 0.005, 0.010, 0.015, 0.020, 0.025 system were prepared using the combustion reaction method. For all the studied perovskite phase, stoichiometries feature KNN was obtained. Using characterisation techniques, it was determined that the BLFO is incorporated in the crystal structure of KNN without modifying present a phase transition. Moreover, It was also proved that the addition of the BLFO to KNN, alters the particle size of the obtained powders and generates magnetic behavior in this ferroelectric.En la búsqueda de un material multiferroico, se prepararon polvos y piezas cerámicas del sistema ferroeléctrico libre de plomo (1-xK0.5Na0.5NbO3-x(Bi0.8La0.2FeO3 (KNN-BLFO (x=0.005, 0.010, 0.015, 0.020, 0.025, mediante el método de reacción por combustión. Para todas las estequiometrias estudiadas se obtuvo la fase perovskita característica del KNN. Con las diferentes caracterizaciones se determinó que el BLFO se incorpora en la estructura cristalina del KNN modificándola sin que se presente una transición de fase. Se comprobó además que la adición del BLFO al KNN, altera el tamaño de partícula de los polvos obtenidos y genera comportamiento magnético en este ferroeléctrico.

Phase relationships in the Al-rich region of the Al-Cu-Er system

International Nuclear Information System (INIS)

Zhang Ligang; Masset, Patrick J.; Cao Fuyong; Meng Fangui; Liu Libin; Jin Zhanpeng

2011-01-01

Research highlights: → One ternary phase τ 1 -Al 8 Cu 4 Er in Al-rich region with a composition of 59.4-60.4 at.% Al, 32.2-33.8 at.% Cu, and 6.4-7.7 at.% Er is observed in both as-cast and annealed alloys. At 673 K, the binary Al 3 Er phase dissolves about 3.51 at.% Cu. → The calculated solidification paths (based on the CALPHAD method) of as-cast alloys are in agreement with the experimental results. → It can be found that the resultant thermodynamic database can be applied to case studies of as-cast alloys, showing that the literature thermodynamic description of the Al-Cu-Er system is reliable as a working basis for computer-assisted alloy design. - Abstract: The Al-rich region of the ternary Al-Cu-Er system is investigated using the method of X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy. Phase equilibria in the Al-rich region of the Al-Cu-Er system at 673 K have been obtained, and the microstructures of as-cast alloys in the Al-rich region are also investigated. One ternary phase τ 1 -Al 8 Cu 4 Er with a composition of 59.4-60.4 at.% Al, 32.2-33.8 at.% Cu, and 6.4-7.7 at.% Er is observed in both as-cast and annealed alloys. At 673 K, the binary Al 3 Er phase dissolves about 3.51 at.% Cu. The calculated solidification paths (based on the CALPHAD method) of as-cast alloys are in agreement with the experimental results.

Correlación de protoporfirina zinc y plomo en sangre en trabajadores de fábricas de baterías, de Bogotá, Colombia Correlation of zinc protoporphyrin with blood lead levels in car battery industry workers in Bogota, Colombia

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Omayda Cárdenas-Bustamante

2001-06-01

Full Text Available Objetivo. Determinar la utilidad de la protoporfirina zinc en sangre (PPz como indicador de exposición a plomo en trabajadores de fábricas de baterías. Material y métodos. Se hizo un estudio transversal en 116 trabajadores de fábricas de baterías del sector informal en Bogotá, Colombia. La información sobre variables generales, ocupacionales y de salud fue obtenida por medio de una entrevista con los trabajadores. Se establecieron dos categorías para los valores de PPz: aquellos por debajo del valor límite de (70 µg/dl, y aquellos por arriba de este valor. Se empleó análisis de regresión lineal para medir la correlación entre los valores logarítmicos de PPz (>70 µg/dl y plomo en sangre (PbS (>38 µg/dl. Resultados. Se encontró un coeficiente de correlación semilogarítmica r=0.54, además de posibles asociaciones estadísticamente significativas entre los niveles elevados de PPz y el oficio actual de exposición directa (RM:3.35, IC 95% 1.02-11.91; p:0.02, emplear plomo como materia prima (RM:7.80, IC 95% 2.96-21.03; phttp://www.insp.mx/salud/index.htmlObjective. To determine the usefulness of zinc protoporphyrin in blood (PPz as an indicator of lead exposure in workers of the homemade car battery industry. Material and methods. A cross-sectional study was performed in 116 workers of the car battery industry in Bogotá, Colombia. Data on general, occupational, and health variables were collected by interview. Two categories of PPz values were established: Those below the cutoff value (70 µg/dL and those above it. A linear regression analysis was performed to measure the correlation between logarithm values of PPz (>70 µg/dL and lead in blood (PbB (>38 µg/dL. Results. A semi-logarithmic correlation coefficient of r=0.54 was found, and statistically significant associations between high levels of PPz and direct exposure to lead were observed (OR:3.35, 95% IC 1.02-11.91; p:0.02; for workers who often use lead as a raw material

Relationship between Al content and substitution mechanism of Al-bearing anhydrous bridgmanites

Science.gov (United States)

Noda, M.; Inoue, T.; Kakizawa, S.

2017-12-01

It is considered that two substitution mechanisms, Tschermak substitution and oxygen vacancy substitution, exist in MgSiO3 bridgmanite for the incorporation of Al in anhydrous condition. Kubo and Akaogi (2000) has conducted the phase equilibrium experiment in the system MgSiO3-Al2O3, and established the phase diagram up to 28 GPa. However the careful observation in the bridgmanite shows that the chemical compositions are slightly deviated from Tschermak substitution join. The same tendency can be also observed in the run products by Irifune et al. (1996). This result indicates that pure Tschermak substitution bridgmanite cannot be stable even in the MgSiO3-Al2O3 join experiment. However, the previous studies used powder samples as the starting materials, so the absorbed water may affect the results. Therefore, we tried to conduct the experiment in the join MgSiO3-Al2O3 in extremely anhydrous condition to clarify whether the pure Tschermak substitution bridgmanite can be stable or not. In addition, we also examined the stability of oxygen vacancy bridgmanite in the extremely anhydrous condition for the comparison. The high pressure synthesis experiments were conducted at 28 GPa and 1600-1700° for 1hour using a Kawai-type multi-anvil apparatus. Four different Al content samples were prepared as the starting materials along the ideal substitution line of Tschermak (Al=0.025, 0.05, 0.1, 0.15 mol) and oxygen-vacancy (Al=0.025, 0.05, 0.075, 0.1 mol) substitutions, respectively (when total cation of 2). The glass rods were used as the starting materials to eliminate the absorbed water on the sample surface. The chemical compositions of the synthesized bridgmanite could not be measured by EPMA because of small grain size less than submicron. Therefore the chemical compositions were estimated from the result of the XRD pattern by subtracting the amount of the other phases. The estimated chemical compositions of Tschermak substitution bridgmanites were consistent with the

Internet Addiction and Its Relationship with Self-Efficacy Level among Al-Hussein Bin Talal University Students

Science.gov (United States)

Alrekebat, Amjad Farhan

2016-01-01

The aim of this study was to identify the Internet addiction and its relationship to self-efficacy level among Al-Hussein Bin Talal University students. The study sample consisted of 300 female and male students, who were selected randomly. The participants completed a questionnaire that consisted of two scales: Internet addiction which was…

Informe final: desarrollo de la tecnología de inmovilización: estabilización / solidificación de desechos peligrosos en Costa Rica

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Luis Guillermo Romero Esquivel

2009-01-01

Full Text Available Se evaluó la tecnología de inmovilización en un lodo proveniente del tratamiento del agua residual del proceso de electrodeposición de cromo y níquel sobre cobre; dos reactivos químicos vencidos de metales tóxicos (plomo y cadmio; y dos residuos sólidos resultantes del tratamiento de desechos líquidos del Instituto Tecnológico de Costa Rica. Para la inmovilización de un lodo proveniente del tratamiento del agua residual del proceso de electrodeposición de cromo y níquel sobre cobre de la empresa Prolex S. A., se evaluó la eficacia de tres tipos de materiales cementantes: cemento Pórtland / carbonato de calcio (50/50 y 75/25; y cemento Pórtland/puzolana (85/15. Con el fin de determinar si el lodo se puede disponer en un relleno sanitario, se determinaron las características toxicas de lixiviación del lodo mediante el método Toxicity Characteristic Leaching Procedure (TCLP, determinándose que los niveles de lixiviación del níquel están por encima de la norma nacional. Se encontró que todos los cementos logran la inmovilización satisfactoria del níquel, pero la mezcla cemento Pórtland/puzolana (85/15 presenta las mejores resistencias mecánicas para la disposición del material tratado en un relleno sanitario; por lo tanto es la más recomendable para el tratamiento. Este tipo de material cementante también se evaluó a nivel piloto, utilizando una mezcladora del tipo empleado en construcción. La resistencia mecánica del material así preparado está cuatro veces por encima de la formulación que utilizaba la empresa Prolex S. A., que incluye un aditivo importado, cemento convencional y piedra. La tecnología de inmovilización también resultó satisfactoria en el tratamiento de reactivos vencidos de metales tóxicos (plomo y cadmio. En este caso, los cementos convencional, Pórtland y Pórtland con puzolanas fueron eficaces al inmovilizar acetato de cadmio en un 11%�

Origin of the modified orientation relationship for S(S'')-phase in Al-Mg-Cu alloys

International Nuclear Information System (INIS)

Kovarik, L.; Miller, M.K.; Court, S.A.; Mills, M.J.

2006-01-01

The formation of S-phase with a modified orientation relationship (OR) has been previously observed in several Al-Cu-Mg alloys. In this paper, high-resolution transmission electron microscopy and Z-contrast imaging have been used to study the origin of the modified OR in an alloy with low Cu/Mg ratio and small Si addition. Based on the observations, and supported by ab initio simulations, the formation is governed by coherency at the (0 2 1) S //(0 1 4) Al S-phase/matrix interface, which is shown to coexist with the more commonly reported (0 0 1) S //(0 2 1) Al interface. This new (0 2 1) S //(0 1 4) Al S-phase/matrix interface explanation is compared with previously published explanations based on the invariant line concept and establishment of a different S-phase/matrix interface. Energy dispersive X-ray spectroscopy and atom probe tomography indicate that the S-phase is slightly enriched in Si. The role of Si as well as the overall alloy composition is discussed. Because of the similarities between our results and the early work of Bagaryatsky, the S''-phase notation is adopted for this early-forming, strained version of the S-phase

Niveles de plomo en la población de alto riesgo y su entorno en San Ignacio, Fresnillo, Zacatecas, México Lead levels in high-risk populations and the surrounding environment in San Ignacio, Fresnillo, Zacatecas, México

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Eduardo Manzanares-Acuña

2006-06-01

Full Text Available OBJETIVO: Determinar la concentración de plomo en la sangre de niños y mujeres, en periodo de lactancia o embarazadas, de la comunidad de San Ignacio, Fresnillo, en Zacatecas, así como en matrices de suelo, plantas, ceniza y barro vidriado, para determinar la exposición que genera una empresa recicladora de metales. MATERIAL Y MÉTODOS: El estudio se realizó de diciembre de 2004 al mes de abril de 2005. El Pb en sangre se midió por voltamperometría de redisolución anódica, mientras que se utilizó energía dispersa de fluorescencia por rayos X para las otras matrices. RESULTADOS: Con base en los criterios de la Norma Oficial Mexicana (NOM se encontró que 90% de los menores está en la categoría I, 5% se encuentra en la categoría II y el otro 5% se ubica en la categoría III. El suelo de los terrenos aledaños a la recicladora tiene en promedio 4 940 µg/g, en un intervalo de 73 a 84 238 µg/g. Las mayores concentraciones se localizan en los puntos más cercanos a la empresa. El suelo de San Ignacio tiene en promedio 109 µg/g. Se encontraron valores altos en el barro vidriado y la concentración del Pb en las plantas es superior a los 300 µg/g. CONCLUSIONES: A pesar de que la mayoría de los niños analizados presenta niveles de plomo en sangre que la Norma Mexicana señala como aceptables, varios estudios indican que existen efectos nocivos aun a concentraciones bajas. Los terrenos aledaños a la empresa están contaminados, y en esa medida los alimentos que ahí se producen, al ser consumidos, son una fuente de contaminación, que se agudiza con el uso de barro vidriado.OBJECTIVE:To determine the lead concentration in the blood of children and nursing or pregnant women from San Ignacio, Fresnillo, in Zacatecas, Mexico as well as in soil, plants, ash and lead-glazed pottery, in order to determine exposure due to a metal-recycling facility. MATERIAL AND METHODS: The study was carried out from December 2004 to April 2005. Lead in

CONTENIDO Y TRASLOCACIÓN DE PLOMO EN AVENA (Avena sativa, L. Y HABA (Vicia faba, L. DE UN SUELO CONTAMINADO

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Elizabeth García-Gallegos

2011-01-01

Full Text Available Un experimento en invernadero se estableció para determinar la concentración de plomo (Pb en suelo, raíz y parte aérea de haba y avena; se calculó el factor de bioconcentración y traslocación en las dos especies. Se probaron 50, 100 y 150 mg·Pb·kg-1 de suelo, incluyendo un control. Las plantas se colectaron a los 60 días después de la siembra y se midieron altura de planta (AP, volumen radical (VR y biomasa seca total (BST, además del contenido de Pb en suelo, raíz y parte aérea. La cuantificación de Pb se realizó por espectrofotometría de absorción atómica. El suelo cultivado con haba presentó un 28.48 % de PbEDTA. Las variables AP, VR y BST no fueron afectadas de manera drástica por las concentraciones de Pb probadas. Las plantas de haba y avena absorbieron un total de 55 mg·kg-1 y 45.3 mg·kg-1, respectivamente, las cuales se consideran tóxicas para plantas cultivadas. Los resultados pueden servir de base para ampliar el conocimiento del contenido de Pb absorbido y traslocado en plantas de haba y avena, ya que la capacidad de tolerar y absorber Pb es específica de la especie, inclusive de la variedad de planta.

Prácticas y Cambios Contables en la Minería del Plomo de la Carolina (Jaén: Estudio de la Empresa Minera el Guindo en los Años Finales del S. XIX y Primer Cuarto del S. XX

Directory of Open Access Journals (Sweden)

José M.ª Carlos Álvarez López

2006-06-01

Full Text Available Hemos investigado sobre los libros contables de la sociedad minera El Guindo (sucursal de la Carolina, situada en el sur de España y dedicada a la extracción de plomo, con el fin de examinar sus prácticas contables y los avances producidos en ellas. Destacamos, como cambios esenciales, en el primer periodo analizado (1899-1925, el paso del criterio de caja al criterio de devengo en los libros principales y, fundamentalmente, la introducción de un criterio de valoración para minerales basado en precios de mercado. Considerando que la admisión a cotización en Bolsa en 1921 fue el hecho más determinante de dichos cambios.With the aim of examining accounting practices and the progress made in this field, we have investigated the accounts books of the mining company El Guindo situated in the south of Spain (the branch in La Carolina, which dealt in the business of the extraction of lead. During the first period analyzed (1899-1925 the most notable changes were the move from a cash-based accounting system to an accrual-based accounting system in the main books and, fundamentally, the introduction of an valuation criterion for minerals based on market prices. Considering the most significant factor that gave rise to these changes to be its listing on the Stock Market in 1921.

Las mineralizaciones argentíferas de Plasenzuela, Cáceres. España

OpenAIRE

Lago Rodríguez, A.; Castroviejo Bolibar, Ricardo; Nodal Ramos, T.

1989-01-01

En el distrito de Plasenzuela, constituido por cinco minas reconocidas y numerosas labores menores, se desarrolló, especialmente en el siglo XIX y a comienzos del XX, una intensa actividad minera para la extracción de menas de plata y plomo. Estas cementan brechas y rellenan fracturas, principalmente de dirección N-S, con buzamientos fuertes al oeste, que ocupan una faja N-S, de unos 10 X 3 Km., próxima al borde occidental del macizo granítico de Plasenzuela. Los materiales encajantes están e...

Microstructure, process, and tensile property relationships in an investment cast near-γTiAl alloy

International Nuclear Information System (INIS)

Jones, P.E.; Porter, W.J. III.; Keller, M.M.; Eylon, D.

1992-01-01

The brittle nature of near-γ TiAl alloys makes fabrication difficult. This paper reports on developing near-net shape technologies, such as investment casting, for these alloys which is one of the essential approached to their commercial introduction. The near-γ TiAl alloy Ti-48Al-2Nb-2Cr (a%) is investment cast with two cooling rates. The effect of casting cooling rate on the fill and surface integrity was studied for complex shape thin walled components. Block and bar castings are hot isostatically pressed (HIP'd) and heat treated to produce duplex (lamellar + equiaxed) microstructures for mechanical property evaluation. The relationships between the casting conditions, microstructures, and tensile properties are studied. The strength and elongation below the ductile to brittle transition temperature are dependent on the casting cooling rate and section size. The tensile properties improved with faster cooling during the casting process as a result of microstructural refinement. Faster cooled castings are more fully transformed to a duplex structure during post-casting heat treatments. Above the ductile to brittle transition temperature the effect of casting cooling rate on tensile properties is less pronounced

La "historia de los omeyas de al-Andalus" en los Masalik al-Absar

OpenAIRE

Molina, Luis

2005-01-01

[ES]Los Masalik al-absar de Ibn Fadl Allah al-`Umari incluyen un breve resumen de la Historia de los omeyas de al-Andalus. En este trabajo se analizan las relaciones textuales entre ese pasaje y el Muqtabis de Ibn Hayyan, crónica que resulta ser la fuente casi única utilizada por al-`Umari para redactar ese capítulo. [EN]The Masalik al-absar by Ibn Fadl Allah al-`Umari contains a brief summary of the Umayyad history in al-Andalus. In this article, the textual relationship between this p...

Refinement of the Fe4Al13 structure and its relationship to the quasihomological homeotypical structures

International Nuclear Information System (INIS)

Grin, J.; Burkhardt, U.; Ellner, M.; Peters, K.

1994-01-01

The crystal structure of Fe 4 Al 13 was refined using single crystal diffractometer data: pearson symbol mC102, space group C2/m; a=15.492(2) A, b=8.078(2) A, c=12.471(1) A, β=107.69(1) ; R F =0.053, R F (w)=0.044 for 1127 reflections and 137 refined parameters. The coordination numbers of atoms are 9, 10, 11 for iron and 10, 12, 13, 14 for aluminium. The shortest interatomic distances are: Fe-Fe - 2.902 A, Fe-Al - 2.374 A, Al-Al - 2.533 A. A preferred occupation of pentagonal prismatic coordinated positions by aluminium was found. The structural relationship between the Fe 4 Al 13 structure and chemically homologous and homeotypical structures of aluminium and gallium containing systems with the 3d transition metals is discussed. The greatest similarity was found concerning the coordination polyhedra, especially that of transition metal atoms. The main common feature of these homeotypical structures is the presence of pentagonal ''channels'', which is strongly dependent on the chemical composition. With increasing atomic number of the 3d transition metal, the stability range of these structures shifts to the transition metal-rich concentration. It is concluded that there is a connection between the occurrence of aluminium and gallium-containing decagonal and icosahedral phases and the existence of the infinite one-dimensional pentagonal channels in the intermetallic compounds showing a similar chemical composition. (orig.)

Bankole et al (2)

African Journals Online (AJOL)

DELL

Relationships of Clay-filled Channels on the Delta Flanks (Modified after Doust and Omatsola, 1990 and Lawrence et al., 2002). ... and in the Indo-Malaysian area (Germeraad et al.,. 1968). The genus ..... Upper Cretaceous of British Guiana.

Mecanismos de movilidad de dislocaciones a temperaturas medias en plomo de muy alta pureza (99.9999 %

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Gallego, I.

1998-05-01

Full Text Available The internal friction spectrum of high purity lead (99.9999 % at medium temperatures has been studied. A new peak (P₁ has been found at 240 K, which has not been studied up to now. The activation energy of the process associated with F, has been determined and its experimental behaviour has also been systematically studied. The comparison between the results and the theoretical predictions of the models of dislocation mobility allows us to attribute the P₁ peak to the sliding of dislocations, controlled by the climbing of jogs induced by the diffusion of vacancies along the dislocation line. This conclusion is analogue to that obtained in previous works for the P₁v peak in very high purity aluminium (99.9999 %.

Se ha realizado un estudio sistemático del espectro de fricción interna del plomo de muy alta pureza (99,9999 % a temperaturas medias, encontrándose un pico a 240 K (P₁ que no ha sido estudiado en la bibliografía hasta el momento. Los análisis mediante fricción interna nos han permitido evaluar la energía de activación del proceso ligado a P₁ y determinar el comportamiento de este pico en función de diversos parámetros. La comparación de los resultados experimentales con las predicciones teóricas de varios modelos microscópicos de movilidad de dislocaciones nos ha permitido concluir que el pico P₁ está asociado con el deslizamiento de dislocaciones controlado por la escalada de escalones mediante la difusión de vacantes a lo largo de, la línea de dislocación. Esta interpretación es análoga a la realizada en trabajos previos para el pico P₁ del aluminio de muy alta pureza (99,9999 %.

Structural and electrical characterization of AuPtAlTi ohmic contacts to AlGaN/GaN with varying annealing temperature and Al content

OpenAIRE

Fay, Mike W.; Han, Y.; Brown, Paul D.; Harrison, Ian; Hilton, K.P.; Munday, A.; Wallis, D.; Balmer, R.S.; Uren, M.J.; Martin, T.

2008-01-01

The effect of varying annealing temperature and Al layer thickness on the structural and electrical characteristics of AuPtAlTi/AlGaN/GaN ohmic contact structures has been systematically investigated. The relationship between annealing temperature, Al content, interfacial microstructure, surface planarity and contact resistance is\\ud examined. In particular, the presence of a detrimental low temperature Pt-Al reaction is identified. This is implicated in both the requirement for a higher Al:T...

The Relationship between Virtue and Happiness in Aristotle and Al-Fārābī’s Views

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Ali Sabri

2016-09-01

Full Text Available Throughout the history, different schools including both descriptive and non-descriptive ones, have been concerned with revealing relationship between happiness and virtue. As the First and Second teachers, Aristotle and Al-Fārābī can be named as having very important roles in this sense. So, the main tenet of ethics for these two philosophers is happiness, which is mostly derived from virtue. Considering theories of these two philosophers, it became evident that Aristotle had significant effects on Islamic thinkers. In other words, they claim they have been strongly influenced by Aristotle’s ideas. An obvious example for this can be ‘Nicomachean Ethics’ which attracted the attention of both western and eastern thinkers. As the greatest and the most salient commentator, Al-Fārābī could elaborate on Aristotle’s ideas on ethics and so suggest a comprehensive theory of ultimate happiness and Utopia' ('al-madīnat al-fāḍilah'. On the other hand, following Aristotle, Al-Fārābī divided ethics into two theoretical and practical branches. Hence, basis of ethical theories introduced by the two of these philosophers is based on happiness; However, Al-Fārābī added notions of Islam and mysticism to happiness. The most straightforward definition that Aristotle offers for happiness concerns an ultimate goal which humans are eagerly seeking to acquire it. He considers the best life as a happy life which can be reached by reasoning about humans’ actions and reactions and through adopting a viewpoint. In this sense, Aristotle introduced three types of lives, namely life with pleasure, political life, and life with intellect; he knows the third type of life better and more sublime than the other two. In his book on ethics, Aristotle defined happiness as soul’s performance according to perfect virtue. Regarding soul, Aristotle divided virtues into moral and rational ones. He believed that virtue is inasmuch as its genus is a hexis (habit

Microstructure/processing relationships in high-energy high-rate consolidated powder composites of Nb-stabilized Ti3Al+TiAl

Energy Technology Data Exchange (ETDEWEB)

Persad, C.; Lee, B.; Hou, C.; Eliezer, Z.; Marcus, H.L.

1989-01-01

A new approach to powder processing is employed in forming titanium aluminide composites. The processing consists of internal heating of a customized powder blend by a fast electrical discharge of a homopolar generator. The high-energy high-rate '1MJ in 1s' pulse permits rapid heating of an electrically conducting powder mixture in a cold wall die. This short time at temperature approach offers the opportunity to control phase transformations and the degree of microstructural coarsening not readily possible with standard powder-processing approaches. This paper describes the consolidation results of titanium aluminide-based powder-composite materials. The focus of this study was the definition of microstructure/processing relationships for each of the composite constituents, first as monoliths and then in composite forms. Non-equilibrium phases present in rapidly solidified TiAl powders are transformed to metastable intermediates en route to the equilibrium gamma phase.

Basílica del Real Monasterio de San Lorenzo de El Escorial. Restauración de las cubiertas y fachadas laterales de la nave central

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Esther de Vega García

2005-12-01

Full Text Available Las patologías del plomo empleado en las cubiertas de la nave central de este templo tan significativo constituían un riesgo para la integridad de las pinturas al fresco de sus bóvedas internas. El artículo relata e ilustra con detalle el montaje de la sobrecubierta de protección para la realización de los trabajos sin exponer al monumento, el proceso de sustitución de los emplomados existentes, la reconstrucción de las buhardillas y, por último, la restauración de las fachadas laterales de la iglesia.

Environmental study on ecological lead risks in soils

OpenAIRE

Maritza Reyes Guzmán; Gerardo Avendaño Prieto

2012-01-01

Rev.esc.adm.neg En el contexto de la Ingeniería Ambiental es bien conocido que el plomo es un metal altamente tóxico que genera problemas graves para la salud humana. La Agencia de Protección Ambiental de los Estados Unidos, indica que una cantidad de 15 µg de plomo por litro, es preocupante, porque puede causar daño en el cerebro y el sistema nervioso. En algunos suelos de la Sabana de Bogotá, se han encontrado concentraciones altas de plomo, que en algunos casos superan los promedios mu...

Low Blood Lead Levels and educational achievement in 7-8 year old children in the Community of Madrid (Spain Bajos niveles de plomo en sangre y rendimiento escolar en niños de 7-8 años en la Comunidad de Madrid (España Baixos níveis de chumbo no sangue e sucesso escolar nas crianças entre os 7-8 anos na Comunidade de Madrid (Espanha

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María José Martínez García

2013-06-01

rendimiento académico de los niños. Los padres rellenaron a su vez una encuesta relativa a las variables sociodemográficas de los niños y su familia.Resultados: El nivel medio de plomo en sangre fue de 4,1 μg/dL DE 1,6 μg/dL (log transformado 3,8 μg/dL, DE 0,2 μg/dL. El análisis multivariado controlando por cofactores sociodemográficos relevantes (entre otros, sexo, edad y nivel de educación de los padres mostró una asociación negativa, pero sin significación estadística.Conclusiones: A pesar de las bajas concentraciones de plomo encontradas en la sangre de los niños de la Comunidad de Madrid y de las limitaciones del diseño, los resultados obtenidos sugieren la existencia de un efecto nocivo del plomo en sangre sobre la conducta y el rendimiento académico de los niños, no significativo.Enquadramento: O chumbo afeta as funções comportamentais e cognitivas das crianças. Não há consenso acerca do atual nível de segurança do chumbo que visa evitar estes efeitos adversos.Métodos: Estudo transversal com 511 crianças de 23 escolas primárias da Comunidade de Madrid, Espanha (Região de Madrid -incluindo a cidade de Madrid e a aglomeração urbano-industrial das cidades satélites que a rodeiam. O nível de chumbo no sangue das crianças foi determinado por espectrofotometria de absorção atómica. Além disso, os professores responderam a um questionário de oito itens sobre o comportamento das crianças e desempenho escolar. Os pais preencheram um questionário sobre as variáveis sociodemográficas das crianças e da família.Resultados: O nível médio de chumbo no sangue das crianças foi de 4,1 μg/dL SD 1,6 μg/dL (log transformado 3,8 μg/dL SD 0,2 μg/ dL. A análise multivariada controlada pelas variáveis sociodemográficas (idade, sexo e nível de escolaridade dos pais, entre outros mostrou uma associação negativa, mas esta não foi estatisticamente significativa.Conclusões: Apesar dos baixos níveis de chumbo encontrados no sangue das

Effect of Al and AlP on the microstructure of Mn-30 wt.%Si alloy

Energy Technology Data Exchange (ETDEWEB)

Wu Yuying [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jing Shi Road 73, Jinan 250061 (China); Liu Xiangfa [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jing Shi Road 73, Jinan 250061 (China)], E-mail: xfliu@sdu.edu.cn

2008-04-15

Effect of Al and AlP particles on the microstructure of near eutectic Mn-Si alloy (Mn-30 wt.%Si) was studied by Electron Probe Micro-analyzer (EPMA) and Differential Scanning Calorimeter (DSC). Crystal lattice correspondence analyses show that both Al and AlP have good lattice matching coherence relationships with MnSi phase, and the addition of Al and AlP particles results in an abnormal eutectic structure, i.e. the eutectic constitution MnSi and Mn{sub 5}Si{sub 3} precipitate separately: MnSi precipitates firstly, and then the Mn{sub 5}Si{sub 3} phase.

[Relationship between Fe, Al oxides and stable organic carbon, nitrogen in the yellow-brown soils].

Science.gov (United States)

Heng, Li-Sha; Wang, Dai-Zhang; Jiang, Xin; Rao, Wei; Zhang, Wen-Hao; Guo, Chun-Yan; Li, Teng

2010-11-01

The stable organic carbon and nitrogen of the different particles were gained by oxidation of 6% NaOCl in the yellow-brown soils. The relationships between the contents of selective extractable Fe/Al and the stable organic carbon/nitrogen were investigated. It shown that amounts of dithionite-citrate-(Fe(d)) and oxalate-(Fe(o)) and pyrophosphate extractable (Fe(p)) were 6-60.8 g x kg(-1) and 0.13-4.8 g x kg(-1) and 0.03-0.47 g x kg(-1) in 2-250 microm particles, respectively; 43.1-170 g x kg(-1) and 5.9-14.0 g x kg(-1) and 0.28-0.78 g x kg(-1) in soils than in arid yellow-brown soils, and that of selective extractable Al are lower in the former than in the latter. Amounts of the stable organic carbon and nitrogen, higher in paddy yellow-brown soils than in arid yellow-brown soils, were 0.93-6.0 g x kg(-1) and 0.05-0.36 g x kg(-1) in 2-250 microm particles, respectively; 6.05-19.3 g x kg(-1) and 0.61-2.1 g x kg(-1) in stabilization index (SI(C) and SI(N)) of the organic carbon and nitrogen were 14.3-50.0 and 11.9-55.6 in 2-250 microm particles, respectively; 53.72-88.80 and 40.64-70.0 in soils than in paddy yellow-brown soils. The organic carbon and nitrogen are advantageously conserved in paddy yellow-brown soil. An extremely significant positive correlation of the stable organic carbon and nitrogen with selective extractable Fe/Al is observed. The most amounts between the stable organic carbon and nitrogen and selective extractable Fe/Al appear in clay particles, namely the clay particles could protect the soil organic carbon and nitrogen.

DETERMINACIÓN DE LA ENTALPIA DE INMERSIÓN Y CAPACIDAD DE ADSORCION DE UN CARBON ACTIVADO EN SOLUCIONES ACUOSAS DE PLOMO

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Liliana Giraldo

2008-03-01

Full Text Available Para un carbón activado comercial se determinan las cantidades de sitios ácidos y básicos totales con valores de 0,45 y 0,55 meqg-1 respectivamente, la entalpía de inmersión en solución 0,1 M de NaOH con un valor de –15,26 Jg-1, la entalpía de inmersión en solución 0,1 M de HCl  con un resultado de –36,63 Jg-1 y el punto de carga cero, PCZ, para un pH de 8,9.  De estos resultados se establece el carácter básico del sólido. Se determina la isoterma de adsorción a 298 K, del carbón activado en soluciones de Pb2+, y se obtiene una capacidad de adsorción de alrededor de 40 mg g-1, para la máxima adsorción. Se determina las entalpías de inmersión del carbón activado en soluciones acuosas de Pb2+, de diferente concentración, en un rango de 10 a 120 mg L-1 y se obtiene valores para la entalpías de inmersión en un rango de 5,12 a 48,7 Jg-1. Se estudia la superficie del carbón activado por microscopía electrónica de barrido antes y después de la adsorción del plomo, lo que permite observar la colocación del metal sobre el sólido.  

Anales de la Estación Experimental de Aula Dei 16 (1-2)

OpenAIRE

CSIC - Estación Experimental de Aula Dei (EEAD)

1982-01-01

187 Págs. Índice: Contribución al conocimiento de la flora micológica de Navarra. IV / L.M. García Bona, pp. 5-39.-- Primary Trisomic Series: Theoretical Sample Size / I. Romagosa y R. Leiva, pp. 40-44.-- Determinación de plomo por espectrofotometría a absorción atómica con atomización electrotérmica después de la extracción con 1-pirrolidín-ditiocarbonato amónico. Aplicación al análisis de agua natural y material vegetal / J. Aznarez, F. Palacios y J.C. Vidal, pp. 45-54.-- Estudio botá...

ALS-based hummock size-distance relationship assessment of Mt Shasta debris avalanche deposit, Northern California, USA

Science.gov (United States)

Tortini, Riccardo; Carn, Simon; van Wyk de Vries, Benjamin

2015-04-01

The failure of destabilized volcano flanks is a likely occurrence during the lifetime of a stratovolcano, generating large debris avalanches and drastically changing landforms around volcanoes. The significant hazards associated with these events in the Cascade range were demonstrated, for example, by the collapse of Mt St Helens (WA), which triggered its devastating explosive eruption in 1980. The rapid modification of the landforms due to these events makes it difficult to estimate the magnitude of prehistoric avalanches. However, the widespread preservation of hummocks along the course of rockslide-debris avalanches is highly significant for understanding the physical characteristics of these landslides. Mt Shasta is a 4,317 m high, snow-capped, steep-sloped stratovolcano located in Northern California. The current edifice began forming on the remnants of an ancestral Mt Shasta that collapsed ~300-380k years ago producing one of the largest debris avalanches known on Earth. The debris avalanche deposit (DAD) covers a surface of ~450 km2 across the Shasta valley, with an estimated volume of ~26 km3. We analyze ALS data on hummocks from the prehistoric Shasta valley DAD in northern California (USA) to derive the relationship between hummock size and distance from landslide source, and interpret the geomorphic significance of the intercept and slope coefficients of the observed functional relationships. Given the limited extent of the ALS survey (i.e. 40 km2), the high-resolution dataset is used for validation of the morphological parameters extracted from freely available, broader coverage DTMs such as the National Elevation Dataset (NED). The ALS dataset also permits the identification of subtle topographic features not apparent in the field or in coarser resolution datasets, including a previously unmapped fault, of crucial importance for both seismic and volcanic hazard assessment in volcanic areas. We present evidence from the Shasta DAD of neotectonic

The Relationship between Virtue and Happiness in Aristotle and Al-Fārābī’s Views

OpenAIRE

Ali Sabri; Seyed Mohammad Kazem Alavi

2016-01-01

Throughout the history, different schools including both descriptive and non-descriptive ones, have been concerned with revealing relationship between happiness and virtue. As the First and Second teachers, Aristotle and Al-Fārābī can be named as having very important roles in this sense. So, the main tenet of ethics for these two philosophers is happiness, which is mostly derived from virtue. Considering theories of these two philosophers, it became evident that Aristotle had significant eff...

Attacking al Qaeda’s Operational Centers of Gravity

Science.gov (United States)

2008-01-01

have allied themselves with al Qaeda.7 The Taliban in Afghanistan have a close relationship with al Qaeda. In Iraq, there are two major insurgent... consanguinity , the ideological affinity between al Qaeda and local insurgents and populations. By designating consanguinity as a decisive point at the...people, materiel, or facilities. Links connect nodes and are behavioral or functional; they could be a command relationship or an ideology. A deci

An??lisis geoestad??stico en el estudio de la explotaci??n de los recursos minerales

OpenAIRE

Chica Olmo, Mario

1987-01-01

La Tesis Doctoral del Sr. Chica Olmo constituye una aproximaci??n geoestad??stica al estudio de explotaci??n de los recursos minerales de modo que en la memoria se recogen las principales conclusiones metodol??gicas te??ricas y practicas alcanzadas a trav??s de diferentes estudios y proyectos llevados a cabo en el dominio minero referentes a dep??sitos de naturaleza variada como carb??n uranio plomo plata... En gran medida los anteriores estudios han sido realizados en el centro de geoestad??...

BASURA ELECTRÓNICA: CUANDO EL PROGRESO ENFERMA AL FUTURO

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Hernán Urbina Joiro

2015-03-01

Full Text Available Es una sombría paradoja que los aparatos que surgieron para apuntalar el futuro hayan empezado a enfermar al futuro mismo: madres embarazadas, niños y jóvenes en regiones vulnerables, como son la mayoría de regiones en el mundo. INTRODUCCIÓN Basura electrónica es todo desecho de un dispositivo diseñado para funcionar con energía eléctrica de redes públicas, baterías u otros campos electromagnéticos. También se conoce como Residuos de Aparatos Eléctricos y Electrónicos (RAEE o Waste Electrical (e-Waste (1. Los aparatos electrónicos funcionales, en estado íntegro, no son basura electrónica, ni fuentes activas de residuos peligrosos, que en ese estado de funcionabilidad están convenientemente empaquetados y en estado no dispersivo. Habría que destrozar e incinerar estos aparatos funcionales, tal como se hace en el reciclaje primitivo, para que sean liberados esos residuos peligrosos. ¿Qué son los residuos peligrosos –la gran amenaza que encarna la basura electrónica–? El Convenio de Basilea (2 establece que son residuos peligrosos, entre otros, los desechos que contengan retardantes de llama policlorados y polibromados; metales pesados como el cromo hexavalente, cadmio, plomo, mercurio, o cobre, también tóxicos derivados de la incineración como los dibenzofuranos y dibenzoparadioxinas –todos típicos de la basura electrónica– e incluso señala como residuo peligroso a la basura con montajes eléctricos y electrónicos –incluidos los cables eléctricos. De modo que toda basura electrónica contiene y genera residuos peligrosos y debe manejarse toda como tal: como basura peligrosa. Por ello la Directiva vigente de la Unión Europea sobre residuos eléctricos y electrónicos (3 exige que todos los aparatos eléctricos y electrónicos lleven un símbolo que impida que vayan al cesto de la basura.

Subsolidus phase relationships of the {beta}-sialon solid solution in the oxygen-rich part of the Nd-Si-Al-O-N system

Energy Technology Data Exchange (ETDEWEB)

Kaiser, A.; Telle, R. [Rheinisch Westfaelische Technische Hochschule Aachen (Germany). Inst. fuer Gesteinshuettenkunde; Herrmann, M.; Richter, H.J.; Hermel, W. [Fraunhofer Inst. Keramische Technologien und Sinterwerkstoffe, Dresden (Germany)

2001-10-01

The subsolidus phase relationships in the Nd{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-SiO{sub 2} system and in the Si{sub 6-z}Al{sub z}O{sub z}N{sub 8-z} (0 {<=} z {<=} 4)-''Al{sub 2}O{sub 3}:AlN''-Al{sub 2}O{sub 3}-Nd{sub 2}O{sub 3}-SiO{sub 2}-range of the Nd-Si-Al-O-N system have been determined. 50 three- and four-phase equilibria were established in this phase region. The phase equilibria define the regions of stable coexistence between {beta}-sialon Si{sub 6-z}Al{sub z}O{sub z}N{sub 8-z} (0 {<=} z {<=} 4) and oxide or oxynitride compounds, which are potential grain boundary phases for silicon nitride ceramics. {beta}-Si{sub 3}N{sub 4} coexists with N-melilite (Nd{sub 2}Si{sub 3-x}Al{sub x}N{sub 4-x} (0 {<=} x {<=} 1)), N-{alpha}-wollastonite NdSi{sub 2}ON, a nitrogen-rich (Al, N)-apatite solid solution and Nd{sub 2}Si{sub 2}O{sub 7}. Between 0 {<=} z {<=} 0.8 {beta}-sialon (Si{sub 6-z}Al{sub z}O{sub z}N{sub 8-z}) is compatible with N-melilite (Nd{sub 2}Si{sub 3-x}Al{sub x}N{sub 4-x} (x = 1)), an (Al,N)-apatite of intermediate composition and Nd{sub 2}Si{sub 2}O{sub 7}. The equilibrium phases between z = 0.8 to z = 4 are NdAlO{sub 3} and the U-phase (Nd{sub 3}Si{sub 3-x}Al{sub 3+x}O{sub 12+x}N{sub 2-x}) as well as NdAl{sub 11+x}O{sub 18}N{sub x} (x = 1) and corundum at the Al-rich terminal composition (z = 4). (orig.)

Niveles intelectuales y ansiedad en niños con intoxicación plúmbica crónica: Colegio "María Reiche". Callao-Perú, 2002

Directory of Open Access Journals (Sweden)

Julián Vega

2005-06-01

Full Text Available Objetivo: Determinar la asociación entre intoxicación plúmbica crónica y niveles intelectuales, y la asociación entre intoxicación plúmbica crónica y ansiedad, en niños del colegio "María Reiche"-Callao. Materiales y Métodos: Se realizó un estudio observacional transversal en 39 niños que participaron en el dosaje de plomo en sangre hecho por la Dirección General de Salud Ambiental en el año 2002. Se midió el coeficiente intelectual y determinó el nivel intelectual, y se aplicó la lista de chequeo de ansiedad. Se categorizó a los niños, según sus niveles de plomo en sangre, en no intoxicados (niveles o = 10 myg/dL. Se aplicó las pruebas chi-cuadrado y prueba t con un p <0,05. Resultados: El coeficiente intelectual de los niños intoxicados fue 85,51±12,56, los niveles de plomo fueron 26,54±9,42 myg/dL en los niños con nivel intelectual bajo (fronterizo e inferior. Los niveles intelectuales y las categorías de plomo en sangre se asociaron con un p=0,355. Los grados de ansiedad y las categorías de plomo en sangre se asociaron con un p=0,03. La distribución t encontró diferencia de medias entre los niveles de plomo en los grupos con ansiedad leve y marcada (p=0,024. Conclusiones: Se encontró asociación entre la intoxicación plúmbica crónica y el grado de ansiedad; sin embargo, no se encontró asociación entre los niveles intelectuales y la intoxicación plúmbica crónica.

Phase relationship in AL-Cu-Sc alloys at 450-500 deg C

International Nuclear Information System (INIS)

Kharakterova, M.L.

1991-01-01

Al-Cu-Sc alloys containing up to 40% Cu and up to 6% Sc at 450 deg C and 500 deg C are studied using light microscopy, X-ray-spectral microanalysis, X-ray diffraction analysis, scanning electron microscopy, measurement of microhardness and electric resistance. It is determined, that in equilibrium with aluminium solid solution under the given temperature ther are Al 3 Sc, CuAl 2 phases of the respective binary systems and W (ScCu 6.6-4 Al 5.4-8 ) ternary phase. Isothermal cross sections of Al-Cu-Sc system at 450 and 500 deg C are plotted. Microhardness of equilibrium phases is measured. Combined solubility of copper and scandium in aluminium is determined

Materiales piezoeléctricos: formas de presentación ventajas y desventajas en las aplicaciones

OpenAIRE

Jiménez, B.

1995-01-01

El enorme desarrollo que han experimentado las aplicaciones de los materiales piezoeléctricos en las nuevas tecnologías se ha debido, fundamentalmente, al descubrimiento de las propiedades ferroeléctricas en los materiales con estructura tipo perovskita de composiciones basadas en el Titanato de Plomo. La posibilidad de preparar soluciones sólidas en forma cerámica y más recientemente el polímero PVDF y los materiales compuestos por una fase activa piezoeléctrica y otra fase no activa , "comp...

Evaluation of Functional Disability in ALS

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Akbar Soltan-Zadeh

2002-06-01

Full Text Available Objective: Amyotrophic Lateral Sclerosis (ALS is a progressive degenerative fatal disorder of motor neuron. In this research course of functional disability and possible underlying factors affecting disability were studied. Materials & Methods: First 59 patients with definite ALS were selected and for each patient ALSFRS (ALS Functional Rating Scale was determined at Initial and the end of a six month period. Results: During this period 9 patients expired. Bulbar onset localization showed a more rapid course than non-bulbar onset group. Conclusion: There was no significant relationship between the age group or gender with progression of disability. In expired group, mean survival in bulbar onset and older patients were significantly less than those with non-bulbar onset and younger ones. There was no significant relationship between survival and gender.

The Relationship between Cognitive Dissonance and Decision-Making Styles in a Sample of Female Students at the University of Umm Al Qura

Science.gov (United States)

Allahyani, Mariam Hameed Ahmed

2012-01-01

The aim of this study is to determine the magnitude of cognitive dissonance present in a sample of female students at Umm Al Qura University, and clarifying the relationship between the cognitive dissonance and decision-making styles. It also aimed to identify differences between female students with high cognitive dissonance and those with low…

Potenciales evocados somatosensitivos en una poblacion cronicamente intoxicada con plomo

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O. M. Genovese

1990-03-01

Full Text Available Once pacientes con cifras elevadas de plombemia y disminuidas de delta aminolevulínico dehidrasa (ALA D, fueron estudiados mediante la realización de potenciales evocados somatosensitivos obtenidos por estimulación del nervio mediano, midiendo el ingreso medular, el arribo cortical v el tiempo de conducción central (TCC. Los datos fueron comparados con controles. Se correlacionaron con las deterniinaciones bioquímicas y con el tiempo de exposición al tóxico. Por encima dei limite superior control, se encontro el ingreso medular en tres pacientes, el arribo cortical en cuatro y el TCC en tres. Los valores de N13,N20 y TCC no mostraron correlación con los parâmetros bioquímicos ni con el tiempo de exposición al tóxico. Estos hallazgos sugieren que, si bien la neuropatía periférica condiciona el retraso dei ingreso medular y del arribo cortical, es probable que exista también compromiso de la mielina central en algunos de los pacientes crónicamente expuestos.

Searching for consensus in molt terminology 11 years after Howell et al.'s "first basic problem"

Science.gov (United States)

Jared D. Wolfe; Erik I. Johnson; Ryan S. Terrill

2014-01-01

Howell et al. (2003) published an innovative augmentation to terminology proposed by Humphrey and Parkes (1959) that classified bird molt on the basis of perceived evolutionary relationships. Despite apparent universal applicability, Howell et al.’s (2003) proposed terminological changes were met with criticism that cited a failure to verify the evolutionary...

Advantage and choice: social relationships and staff assistance in assisted living.

Science.gov (United States)

Burge, Stephanie; Street, Debra

2010-05-01

OBJECTIVES. To understand how "cumulative inequality" (CI), expressed as individual advantage and choice, and "external social supports" contribute to the quality of social relationships and perceptions of staff assistance for older individuals in different assisted living (AL) settings. Data are from 429 cognitively intact AL residents aged 60 years and older interviewed for the Florida Study of Assisted Living. Bivariate and multivariate statistical analyses show how individual advantage and choice and external social networks influence respondents' social relationships and staff assistance in AL. Controlling for resident and facility characteristics, being able to pay privately enhances resident satisfaction with staff assistance and having control over the move to AL is positively associated with perceptions of staff relationships and assistance. Maintaining contact with pre-AL friends predicts quality of coresident relationships, as does family contact. Regular contact with family buffers some of the disadvantages associated with CI for perceptions of staff relationships but not perceptions of staff assistance. Discussion. Individual advantage and choice influence the quality of staff relationships and assistance for AL residents but matter little for coresident relationships. External social relationships buffer some of the risks associated with CI for perceptions of staff relationships but not perceived quality of staff assistance. Findings highlight outcomes associated with CI, including predictable risks that disadvantaged elders face in particular types of AL settings, differential advantages others enjoy that influence positive perceptions of staff relationships and staff assistance, and the enduring importance of supportive social relationships.

The structure-property relationships of powder processed Fe-Al-Si alloys

Energy Technology Data Exchange (ETDEWEB)

Prichard, Paul D. [Iowa State Univ., Ames, IA (United States)

1998-02-23

Iron-aluminum alloys have been extensively evaluated as semi-continuous product such as sheet and bar, but have not been evaluated by net shape P/M processing techniques such as metal injection molding. The alloy compositions of iron-aluminum alloys have been optimized for room temperature ductility, but have limited high temperature strength. Hot extruded powder alloys in the Fe-Al-Si system have developed impressive mechanical properties, but the effects of sintering on mechanical properties have not been explored. This investigation evaluated three powder processed Fe-Al-Si alloys: Fe-15Al, Fe-15Al-2.8Si, Fe-15Al-5Si (atomic %). The powder alloys were produced with a high pressure gas atomization (HPGA) process to obtain a high fraction of metal injection molding (MIM) quality powder (D₈₄ < 32 μm). The powders were consolidated either by P/M hot extrusion or by vacuum sintering. The extruded materials were near full density with grain sizes ranging from 30 to 50 μm. The vacuum sintering conditions produced samples with density ranging from 87% to 99% of theoretical density, with an average grain size ranging from 26 μm to 104 μm. Mechanical property testing was conducted on both extruded and sintered material using a small punch test. Tensile tests were conducted on extruded bar for comparison with the punch test data. Punch tests were conducted from 25 to 550 C to determine the yield strength, and fracture energy for each alloy as a function of processing condition. The ductile to brittle transition temperature (DBTT) was observed to increase with an increasing silicon content. The Fe-15Al-2.8Si alloy was selected for more extensive testing due to the combination of high temperature strength and low temperature toughness due to the two phase α + DO₃ structure. This investigation provided a framework for understanding the effects of silicon in powder processing and mechanical property behavior of Fe-Al-Si alloys.

Optical phonon scattering on electronic mobility in Al2O3/AlGaN/AlN/GaN heterostructures

Science.gov (United States)

Zhou, X. J.; Qu, Y.; Ban, S. L.; Wang, Z. P.

2017-12-01

Considering the built-in electric fields and the two-mode property of transverse optical phonons in AlGaN material, the electronic eigen-energies and wave functions are obtained by solving Schrödinger equation with the finite difference method. The dispersion relations and potentials of the optical phonons are given by the transfer matrix method. The mobility of the two dimensional electron gas influenced by the optical phonons in Al2O3/AlGaN/AlN/GaN heterostructures is investigated based on the theory of Lei-Ting force balance equation. It is found that the scattering from the half-space phonons is the main factor affecting the electronic mobility, and the influence of the other phonons can be ignored. The results show that the mobility decreases with increasing the thicknesses of Al2O3 and AlN layers, but there is no definite relationship between the mobility and the thickness of AlGaN barrier. The mobility is obviously reduced by increasing Al component in AlGaN crystal to show that the effect of ternary mixed crystals is important. It is also found that the mobility increases first and then decreases as the increment of the fixed charges, but decreases always with increasing temperature. The heterostructures constructed here can be good candidates as metal-oxide-semiconductor high-electron-mobility-transistors since they have higher electronic mobility due to the influence from interface phonons weakened by the AlN interlayer.

El estrés oxidativo como mecanismo de acción del plomo: Implicancias terapéuticas Oxidative stress as a mechanism of action of lead: Therapeutic implications

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Samanta Andrea Martínez

2011-12-01

Full Text Available El plomo (Pb es un metal no esencial altamente tóxico que afecta a diversos órganos y tejidos. Si bien aún no ha sido descripto un mecanismo único mediante el cual este metal ejerce sus efectos tóxicos, un gran número de estudios han puesto en evidencia el rol fundamental del estrés oxidativo en la intoxicación por Pb. A este respecto, ha sido informado que en la intoxicación por Pb el estrés oxidativo puede ocurrir a diferentes niveles: por generación de ácido ä-aminolevulínico (ä-ALA, por la capacidad per se que posee el Pb para inducir peroxidación lipídica en presencia de ión ferroso (Fe2+, o por depleción de glutatión (GSH y enzimas antioxidantes. Sobre la base de estos antecedentes, el objetivo de esta revisión es presentar evidencias recientes sobre la implicancia del estrés oxidativo en los efectos adversos ocasionados por Pb, destacar la posibilidad de utilización de biomarcadores de estrés oxidativo como un método complementario al diagnóstico temprano de exposición y revelar la importancia de los compuestos antioxidantes como nuevas herramientas en la prevención y tratamiento de la intoxicación por este metal.Lead (Pb is a highly toxic non-essential metal that affects different organs and tissues. Although at the present a unique mechanism by which this metal exerts its toxic effects has not been described, a large number of studies have highlighted the fundamental role of oxidative stress in the pathophysiology of Pb poisoning. In this regard, it has been reported that Pb-induced oxidative stress can occur at different levels: by the generation of ä-aminolevulinic acid (ä-ALA, through its ability to induce lipid peroxidation in the presence of ferrous ion (Fe2+, or via glutathione (GSH or antioxidant enzyme depletion. On the basis of these antecedents, the aim of this review is to present recent evidence regarding the implication of oxidative stress in the adverse effects caused by Pb, to emphasize the

Exposición ocupacional y ambiental al arsénico: actualización bibliográfica para investigación científica

OpenAIRE

Augusto V. Ramírez

2013-01-01

El arsénico (As) es un metaloide presente en minerales complejos que contienen cobre, plomo y otros; en el trabajador causa arsenicismo ocupacional y la principal exposición ocurre en metalurgia del cobre. Sus compuestos trivalentes tienen tendencia acumulativa e ingresan por las vías respiratoria, digestiva o cutánea y se transforman en los ácidos dimetilarsínico y metilarsónico. En la mitocondria, con el azufre de los grupos mercapto forma enlaces covalentes y desacopla la fosforilación oxi...

Diseño de una instalación fotovoltaica autónoma para la finca "Mis Delirios" en Pereira - Colombia

OpenAIRE

Santa García, Pedro Andrés

2014-01-01

El objetivo principal del trabajo estará enfocado al diseño, dimensionado y estudio de viabilidad económica de una instalación fotovoltaica aislada, soportada por baterías de plomo-ácido. El emplazamiento para el cual se hará el diseño, es una pequeña finca de descanso de uso privado, la cual también sostiene pequeñas actividades agropecuarias. La ubicación de este emplazamiento se encuentra en Pereira, Colombia, zona de clima templado. El interés de realizar este proyecto, ...

Análisis geoestadístico en el estudio de la explotación de los recursos minerales

OpenAIRE

Chica Olmo, Mario

2013-01-01

La Tesis Doctoral del Sr. Chica Olmo constituye una aproximación geoestadística al estudio de explotación de los recursos minerales de modo que en la memoria se recogen las principales conclusiones metodológicas teóricas y practicas alcanzadas a través de diferentes estudios y proyectos llevados a cabo en el dominio minero referentes a depósitos de naturaleza variada como carbón uranio plomo plata... En gran medida los anteriores estudios han sido realizados en el centro de geoestadística de ...

Structure–activity relationships of Pt/Al₂O₃ catalysts for CO and NO oxidation at diesel exhaust conditions

DEFF Research Database (Denmark)

Boubnov, Alexey; Dahl, Søren; Johnson, Erik

2012-01-01

Structure–performance relationships for Pt/Al2O3 catalysts with mean Pt particle sizes of 1, 2, 3, 5 and 10nm are investigated for the catalytic oxidation of CO and NO under lean-burning diesel exhaust conditions. The most active catalysts for CO oxidation exhibit Pt particles of 2–3nm, having...

Successful Separationists in a Unity Fan Society: Al-Hirak Al-Janubi Social Movement in the Republic of Yemen

Science.gov (United States)

2013-12-01

Al-Janubi’s popularity and motivations. Jennifer Earl uses three key typology dimensions to categorize repression of a given movement. Those...use Earl’s typology of repression as an attempt to understand the effects on the relationship between the government and Al-Hirak Al-Janubi in Yemen...let him invest in Aden; then he would sell him the sea area to dump rocks onto it to make it suitable as a tourist site. Finally, he would sell him

Thermodynamic assessments and inter-relationships between systems involving Al, Am, Ga, Pu, and U

Energy Technology Data Exchange (ETDEWEB)

Perron, A., E-mail: perron1@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Turchi, P.E.A.; Landa, A. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Oudot, B.; Ravat, B.; Delaunay, F. [CEA-Centre de Valduc, 21120, Is sur Tille (France)

2016-12-15

A newly developed self-consistent CALPHAD thermodynamic database involving Al, Am, Ga, Pu, and U is presented. A first optimization of the slightly characterized Am-Al and completely unknown Am-Ga phase diagrams is proposed. To this end, phase diagram features as crystal structures, stoichiometric compounds, solubility limits, and melting temperatures have been studied along the U-Al → Pu-Al → Am-Al, and U-Ga → Pu-Ga → Am-Ga series, and the thermodynamic assessments involving Al and Ga alloying are compared. In addition, two distinct optimizations of the Pu-Al phase diagram are proposed to account for the low temperature and Pu-rich region controversy. The previously assessed thermodynamics of the other binary systems (Am-Pu, Am-U, Pu-U, and Al-Ga) is also included in the database and is briefly described in the present work. Finally, predictions on phase stability of ternary and quaternary systems of interest are reported to check the consistency of the database.

Exposición ocupacional y ambiental al arsénico: actualización bibliográfica para investigación científica

Directory of Open Access Journals (Sweden)

Augusto V. Ramírez

2013-07-01

Full Text Available El arsénico (As es un metaloide presente en minerales complejos que contienen cobre, plomo y otros; en el trabajador causa arsenicismo ocupacional y la principal exposición ocurre en metalurgia del cobre. Sus compuestos trivalentes tienen tendencia acumulativa e ingresan por las vías respiratoria, digestiva o cutánea y se transforman en los ácidos dimetilarsínico y metilarsónico. En la mitocondria, con el azufre de los grupos mercapto forma enlaces covalentes y desacopla la fosforilación oxidativa, sugiriendo una acción inhibitoria no hidrolítica a ese nivel. Es cancerígeno para varios órganos. Se excreta por orina, heces y piel. Los peces y mariscos contienen arsénico orgánico. En sujetos no expuestos, dependiendo de la dieta, el As inorgánico en orina es < 5 ug/L. El índice de exposición biológica para trabajadores medido al final de la semana laboral es 35 µg/g creatinina y el valor límite umbral para ambientes de trabajo es 0,01mg/m³. La arsina es el compuesto arsenical más tóxico. El arsénico contenido en el agua de ciertas regiones produce la enfermedad ambiental llamada hidroarsenicismo crónico regional endémico.

Insulator-semiconductor interface fixed charges in AlGaN/GaN metal-insulator-semiconductor devices with Al2O3 or AlTiO gate dielectrics

Science.gov (United States)

Le, Son Phuong; Nguyen, Duong Dai; Suzuki, Toshi-kazu

2018-01-01

We have investigated insulator-semiconductor interface fixed charges in AlGaN/GaN metal-insulator-semiconductor (MIS) devices with Al2O3 or AlTiO (an alloy of Al2O3 and TiO2) gate dielectrics obtained by atomic layer deposition on AlGaN. Analyzing insulator-thickness dependences of threshold voltages for the MIS devices, we evaluated positive interface fixed charges, whose density at the AlTiO/AlGaN interface is significantly lower than that at the Al2O3/AlGaN interface. This and a higher dielectric constant of AlTiO lead to rather shallower threshold voltages for the AlTiO gate dielectric than for Al2O3. The lower interface fixed charge density also leads to the fact that the two-dimensional electron concentration is a decreasing function of the insulator thickness for AlTiO, whereas being an increasing function for Al2O3. Moreover, we discuss the relationship between the interface fixed charges and interface states. From the conductance method, it is shown that the interface state densities are very similar at the Al2O3/AlGaN and AlTiO/AlGaN interfaces. Therefore, we consider that the lower AlTiO/AlGaN interface fixed charge density is not owing to electrons trapped at deep interface states compensating the positive fixed charges and can be attributed to a lower density of oxygen-related interface donors.

Niveles de plomo sanguíneo en madres y recién nacidos derechohabientes del Instituto Mexicano del Seguro Social Blood lead levels in newborn children and mothers covered by the Mexican Institute of Social Security

Directory of Open Access Journals (Sweden)

Joel Navarrete-Espinosa

2000-09-01

Full Text Available OBJETIVO: Establecer la relación entre el nivel de plomo sanguíneo materno (PSM y el de sangre en cordón umbilical (PSC al momento del parto, así como determinar los principales predictores del PSM en derechohabientes del Instituto Mexicano del Seguro Social (IMSS, en el Distrito Federal (D.F.. MATERIAL Y MÉTODOS: Se realizó un estudio transversal en el que se reclutaron voluntarias con embarazo normoevolutivo y se les tomaron muestras de sangre al momento del parto, en cuatro hospitales del IMSS en el D.F., de 1991 a 1993. Se tomó, además, muestra de sangre de cordón umbilical. Los datos fueron analizados mediante regresión lineal simple y múltiple. RESULTADOS: Se estudiaron un total de 1 404 binomios madre-hijo; el promedio de edad de las madres fue de 25 años. La media de PSM fue 10.7 ± 6.5 µg/dl; no se encontraron variaciones significativas por hospital, edad o estado civil. Para el PSC la media fue de 10.4 ± 6.2 µg/dl. Por cada aumento en una unidad logarítmica de PSM, el PSC aumenta 0.62 (pOBJECTIVE: To establish the relation between maternal blood lead (MBL and umbilical cord blood lead (CBL levels during delivery, and to determine the major predictors for MBL in women covered by the Mexican Institute of Social Security (MISS, in Mexico City. MATERIAL AND METHODS: From 1991 to 1993, a cross-sectional study was conducted in four MISS hospitals, among normal pregnant women who volunteered to participate. Blood samples were taken from women and from the umbilical cord during delivery. Statistical analysis consisted of descriptive statistics and simple and multiple linear regression. RESULTS: A total of 1 404 mother-newborn pairs were studied. Mean maternal age was 25 years. MBL average was 10.7 ± 6.5 µg/dl; no significant differences were found by hospital, age, or marital status. Mean CBL was 10.4 ± 6.2 µg/dl. A log unit increase in MBL corresponded to a log increase of 0.62 in CBL (p< 0.01. Pearson's correlation was 0

Experimental and thermodynamic investigation of Al-Cu-Nd ternary system

Energy Technology Data Exchange (ETDEWEB)

Bai, W.M. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Jiang, Y. [Hunan Sushi Guangbo Testing Techniques Co. LTD, Changsha (China); Guo, Z.Y.; Zeng, L.J.; Tan, M.Y. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Meggs, C. [School of Metallurgy and Materials, The University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Zhang, L.G., E-mail: ligangzhang@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Liu, L.B., E-mail: pdc@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China); Jin, Z.P. [School of Materials Science and Engineering, Central South University, Changsha, 410083 (China)

2017-07-01

The phase relationships in the Al–Cu-Nd ternary system at 673 K have been investigated by X-ray powder diffraction (XRD) and scanning electron microscope (SEM) with energy disperse X-ray spectroscopy (EDS) in backscattered electron imaging (BSE) modes. The existence of six ternary Stoichiometric compounds, namely τ{sub 1}-Al{sub 8}Cu{sub 4}Nd, τ{sub 2}-Al{sub 9}Cu{sub 8}Nd{sub 2}, τ{sub 3}-Al{sub 6}Cu{sub 7}Nd, τ{sub 4}-Al{sub 2.4}Cu{sub 8.6}Nd, τ{sub 5}-Al{sub 3}CuNd, τ{sub 6}-AlCuNd, have been confirmed. A complete thermodynamic description of the Al–Cu-Nd ternary system coupled with the CALPHAD method is obtained based on experimental results and first-principles calculations. The calculated phase equilibria were in agreement with the available experimental data. - Highlights: • Phase relationships in the Al-Cu-Nd system has been systematically investigated. • 9 three-phase regions and 4 two-phase regions are confirmed. • A complete thermodynamic description of the Al-Cu-Nd system is obtained. • Results of first-principle calculation consist with thermodynamic calculation.

On the Correlation between Morphology of alpha and Its Crystallographic Orientation Relationship with TiB and Beta in Boron Containing Ti-5Al-5Mo-5V-3Cr-0.5Fe Alloy (Preprint)

Science.gov (United States)

2012-01-01

orientation microscopy studies on a boron containing version of the commercial Ti- 5Al-5Mo-5V-3Cr-0.5Fe ( Ti5553 ) alloy. 15. SUBJECT TERMS Ti5553 ...of the commercial Ti-5Al-5Mo-5V-3Cr-0.5Fe ( Ti5553 ) alloy. Keywords: Ti5553 , TiB, EBSD, crystallography, orientation relationship. Paper There has...absence of orientation relationships between the α, β and TiB phases, on the morphology of α nucleating from TiB in the Ti5553 alloy.. The base

Valores referenciales de plombemia en el área de Buenos Aires.: Población adulta sana no expuesta laboralmente

OpenAIRE

Clara Magdalena, López; Adriana Emilce, Piñeiro; Valeria, Pongelli; Villaamil Lepori, Edda Cristina; Roses, Otmaro Enrique

2005-01-01

Los niveles de plomo en sangre fueron determinados en una población adulta sana y no expuesta laboralmente al metal, habitantes de la Ciudad Autónoma de Buenos Aires y del Gran Buenos Aires. Las muestras de sangre venosa provenientes de sujetos de ambos sexos (n = 278) fueron procesadas por absorción atómica-atomización electrotérmica a 283,3 nm. Los valores de plombemia obtenidos para la población total fueron de 2,27 a 17,35 µg/dL. La población femenina estudiada (n = 123) tuvo valores comp...

Structure-property relationships in an Al matrix Ca nanofilamentary composite conductor with potential application in high-voltage power transmission

Science.gov (United States)

Tian, Liang

This study investigated the processing-structure-properties relationships in an Al/Ca composites using both experiments and modeling/simulation. A particular focus of the project was understanding how the strength and electrical conductivity of the composite are related to its microstructure in the hope that a conducting material with light weight, high strength, and high electrical conductivity can be developed to produce overhead high-voltage power transmission cables. The current power transmission cables (e.g., Aluminum Conductor Steel Reinforced (ACSR)) have acceptable performance for high-voltage AC transmission, but are less well suited for high-voltage DC transmission due to the poorly conducting core materials that support the cable weight. This Al/Ca composite was produced by powder metallurgy and severe plastic deformation by extrusion and swaging. The fine Ca metal powders have been produced by centrifugal atomization with rotating liquid oil quench bath, and a detailed study about the atomization process and powder characteristics has been conducted. The microstructure of Al/Ca composite was characterized by electron microscopy. Microstructure changes at elevated temperature were characterized by thermal analysis and indirect resistivity tests. The strength and electrical conductivity were measured by tensile tests and four-point probe resistivity tests. Predicting the strength and electrical conductivity of the composite was done by micro-mechanics-based analytical modeling. Microstructure evolution was studied by mesoscale-thermodynamics-based phase field modeling and a preliminary atomistic molecular dynamics simulation. The application prospects of this composite was studied by an economic analysis. This study suggests that the Al/Ca (20 vol. %) composite shows promise for use as overhead power transmission cables. Further studies are needed to measure the corrosion resistance, fatigue properties and energized field performance of this composite.

Microstructure and Tensile/Corrosion Properties Relationships of Directionally Solidified Al-Cu-Ni Alloys

Science.gov (United States)

Rodrigues, Adilson V.; Lima, Thiago S.; Vida, Talita A.; Brito, Crystopher; Garcia, Amauri; Cheung, Noé

2018-03-01

Al-Cu-Ni alloys are of scientific and technological interest due to high strength/high temperature applications, based on the reinforcement originated from the interaction between the Al-rich phase and intermetallic composites. The nature, morphology, size, volume fraction and dispersion of IMCs particles throughout the Al-rich matrix are important factors determining the resulting mechanical and chemical properties. The present work aims to evaluate the effect of the addition of 1wt%Ni into Al-5wt%Cu and Al-15wt%Cu alloys on the solidification rate, macrosegregation, microstructure features and the interrelations of such characteristics on tensile and corrosion properties. A directional solidification technique is used permitting a wide range of microstructural scales to be examined. Experimental growth laws relating the primary and secondary dendritic spacings to growth rate and solidification cooling rate are proposed, and Hall-Petch type equations are derived relating the ultimate tensile strength and elongation to the primary dendritic spacing. Considering a compromise between ultimate tensile strength and corrosion resistance of the examined alloys samples from both alloys castings it is shown that the samples having more refined microstructures are associated with the highest values of such properties.

La «historia de los omeyas de al-Andalus» en los Masālik al-Abṣār

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Molina, Luis

2005-06-01

Full Text Available The Māsilik al-abṣār by Ibn Faḍl Allāh al-'Umarī contains a brief summary of the Umayyad history in al-Andalus. In this article, the textual relationship between this passage and the Muqtabis by Ibn Ḥayyān is analysed. Ibn Ḥayyān's chronicle has proved to be the most important source used by al-'Umarī to compose this chapter.

Los Māsilik al-abṣār de Ibn Faḍl Allāh al-'Umarī incluyen un breve resumen de la Historia de los omeyas de al-Andalus. En este trabajo se analizan las relaciones textuales entre ese pasaje y el Muqtabis de Ibn Ḥayyān, crónica que resulta ser la fuente casi única utilizada por al-'Umarī para redactar ese capítulo.

The Impact of Al-Islam on the African American Population.

Science.gov (United States)

Lumumba, Hakeem

2003-01-01

This article explores different aspects of the Islamic religion, or Al-Islam, including the beliefs and religious practices of Muslims; the historical relationship among Africa, African Americans, and Al-Islam; and the current and future implications for African Americans. (Contains 25 references.) (GCP)

Propuesta de intervención en las condiciones ambientales de trabajo

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Urueña Téllez William

1993-12-01

Full Text Available

En Colombia, según el informe de enfermedad profesional 1990, de la División de Salud Ocupacional del Instituto de Seguros Sociales, el sector de construcción de maquinaria eléctrica ocupó el primer puesto de las intoxicaciones por plomo con el 50.4% siendo la construcción de baterías la generadora de esta patología, por utilizar el plomo como una de las materias primas esenciales.

Theory and X-ray Absorption Spectroscopy for Aluminum Coordination Complexes – Al K-Edge Studies of Charge and Bonding in (BDI)Al, (BDI)AlR2, and (BDI)AlX2 Complexes.

Science.gov (United States)

Altman, Alison B; Pemmaraju, C D; Camp, Clément; Arnold, John; Minasian, Stefan G; Prendergast, David; Shuh, David K; Tyliszczak, Tolek

2015-08-19

its valence electronic structure from that of the formally trivalent compounds (BDI)AlX2 and (BDI)AlR2. The work shows that Al K-edge XANES spectroscopy can be used to provide valuable insight into electronic structure and reactivity relationships for main-group coordination compounds.

ATXN2 trinucleotide repeat length correlates with risk of ALS.

Science.gov (United States)

Sproviero, William; Shatunov, Aleksey; Stahl, Daniel; Shoai, Maryam; van Rheenen, Wouter; Jones, Ashley R; Al-Sarraj, Safa; Andersen, Peter M; Bonini, Nancy M; Conforti, Francesca L; Van Damme, Philip; Daoud, Hussein; Del Mar Amador, Maria; Fogh, Isabella; Forzan, Monica; Gaastra, Ben; Gellera, Cinzia; Gitler, Aaron D; Hardy, John; Fratta, Pietro; La Bella, Vincenzo; Le Ber, Isabelle; Van Langenhove, Tim; Lattante, Serena; Lee, Yi-Chung; Malaspina, Andrea; Meininger, Vincent; Millecamps, Stéphanie; Orrell, Richard; Rademakers, Rosa; Robberecht, Wim; Rouleau, Guy; Ross, Owen A; Salachas, Francois; Sidle, Katie; Smith, Bradley N; Soong, Bing-Wen; Sorarù, Gianni; Stevanin, Giovanni; Kabashi, Edor; Troakes, Claire; van Broeckhoven, Christine; Veldink, Jan H; van den Berg, Leonard H; Shaw, Christopher E; Powell, John F; Al-Chalabi, Ammar

2017-03-01

We investigated a CAG trinucleotide repeat expansion in the ATXN2 gene in amyotrophic lateral sclerosis (ALS). Two new case-control studies, a British dataset of 1474 ALS cases and 567 controls, and a Dutch dataset of 1328 ALS cases and 691 controls were analyzed. In addition, to increase power, we systematically searched PubMed for case-control studies published after 1 August 2010 that investigated the association between ATXN2 intermediate repeats and ALS. We conducted a meta-analysis of the new and existing studies for the relative risks of ATXN2 intermediate repeat alleles of between 24 and 34 CAG trinucleotide repeats and ALS. There was an overall increased risk of ALS for those carrying intermediate sized trinucleotide repeat alleles (odds ratio 3.06 [95% confidence interval 2.37-3.94]; p = 6 × 10 -18 ), with an exponential relationship between repeat length and ALS risk for alleles of 29-32 repeats (R 2  = 0.91, p = 0.0002). No relationship was seen for repeat length and age of onset or survival. In contrast to trinucleotide repeat diseases, intermediate ATXN2 trinucleotide repeat expansion in ALS does not predict age of onset but does predict disease risk. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Fragility and structure of Al-Cu alloy melts

International Nuclear Information System (INIS)

Lv Xiaoqian; Bian Xiufang; Mao Tan; Li Zhenkuan; Guo Jing; Zhao Yan

2007-01-01

The dynamic viscosity measurements are performed for Al-Cu alloy melts with different compositions using an oscillating-cup viscometer. The results show that the viscosities of Al-Cu alloy melts increase with the copper content increasing, and also have a correlation with the correlation radius of clusters, which is measured by the high-temperature X-ray diffractometer. It has also been found that the fragilities of superheated melts (M) of hypereutectic Al-Cu alloys increase with the copper content increasing. There exists a relationship between the fragility and the structure in Al-Cu alloy melts. The value of the M reflects the variation of activation energy for viscous flow

Phytoremediation capacity of five high andean species from soils contaminated with heavy metals

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Enoc Jara-Peña

2014-10-01

Full Text Available La fitorremediación consiste en el uso de plantas para remediar in situ suelos, sedimentos, agua y aire contaminados por desechos orgánicos, nutrientes o metales pesados, eliminando los contaminantes del ambiente o haciéndolos inocuos. El trabajo fue realizado en condiciones de invernadero en el distrito de Lachaqui, Provincia de Canta, Departamento de Lima, de octubre de 2011 a octubre de 2012. Fueron evaluados veinte tratamientos con un diseño factorial completo 5 x 4: 5 especies alto andinas, y 4 sustratos con 30%, 60%,100% de relave de mina (RM y suelo sin RM. La producción de biomasa disminuyó significativamente en Solanum nitidum, Brassica rapa, Fuertesimalva echinata y Urtica urens y Lupinus ballianus, con el tratamiento de 100% de relave de mina. La mayor eficiencia de acumulación de plomo y zinc fue obtenida en las raíces de Fuertesimalva echinata con el tratamiento de 100% de relave de mina, obteniendo 2015.1 mg de plomo kg-1 MS y 1024.2 mg de zinc kg-1 MS. En las raíces de L. ballianus fue obtenida la más alta acumulación de cadmio, con una concentración de 287.3 mg kg-1 MS con el tratamiento de 100% de relave de mina. Fuertesimalva echinata presentó el mayor índice de tolerancia (IT al tratamiento de 100% de relave de mina, con un IT de 41.5%, pero, S. nitidum y L. ballianus presentaron el mayor IT al tratamiento de 60% de relave de mina con IT de 68.5% y 67.9.

Avances en los métodos de recuperación de oro y plata de minerales refractarios

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Parga, J. R.

1996-08-01

Full Text Available Recent research work in hydrometallurgical processes for precious metals recovery from refractory ores is analyzed. Advantages and applications are discussed. Likewise, two methods, one stage direct pressure oxidation/cyanidation and pyrometallurgical recovery, are also described. In the first one, gold and silver oxidation and recovery can be carried out in the same reactor simultaneously. A higher than 96 % recovery in less than 90 min can be achieved. As for the pyrometallurgical recovery method, lead paste from automotive discharged batteries is use and no sulfur dioxide is generated. A precious metals recovery higher than 96 % is reached.

En este artículo se analizan algunos de los avances introducidos en los procedimientos hidrometalúrgicos para la recuperación de los metales preciosos contenidos en minerales refractarios y se describen sus ventajas y aplicaciones específicas. Asimismo, se muestran dos procedimientos, la cianuración oxidante a presión en una etapa y la recuperación pirometalúrgica con plomo de metales preciosos. En el proceso de cianuración oxidante a presión, la oxidación y disolución del oro y de la plata se realizan simultáneamente en el mismo reactor, con recuperaciones de ambos superiores al 96 % en 90 min. Con respecto al método de recuperación pirometalúrgica, se emplea pasta de plomo de baterías de automóviles desechadas, sin que se genere dióxido de azufre, obteniéndose también elevados valores de recuperación de los metales preciosos (> 96 %.

Off-state electrical breakdown of AlGaN/GaN/Ga(AlN HEMT heterostructure grown on Si(111

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Shuiming Li

2016-03-01

Full Text Available Electrical breakdown characteristics of AlxGa1−xN buffer layers grown on Si(111 are investigated by varying the carbon concentration ([C]: from ∼1016 to 1019 cm−3, Al-composition (x = 0 and 7%, and buffer thickness (from 1.6 to 3.1 μm. A quantitative relationship between the growth conditions and carbon concentration ([C] is established, which can guide to grow the Ga(AlN layer with a given [C]. It is found that the carbon incorporation is sensitive to the growth temperature (T (exponential relationship between [C] and 1/T and the improvement of breakdown voltage by increasing [C] is observed to be limited when [C] exceeding 1019 cm−3, which is likely due to carbon self-compensation. By increasing the highly resistive (HR Al0.07Ga0.93N buffer thickness from 1.6 to 3.1 μm, the leakage current is greatly reduced down to 1 μA/mm at a bias voltage of 1000 V.

Social Relationships and Allostatic Load in the MIDUS Study

Science.gov (United States)

Brooks, Kathryn P.; Gruenwald, Tara; Karlamanga, Arun; Hu, Peifung; Koretz, Brandon; Seeman, Teresa E.

2014-01-01

OBJECTIVE This study examines how the social environment is related to allostatic load (AL), a multi-system index of biological risk. METHODS A national sample of adults (N = 949) aged 34-84 rated their relationships with spouse, family, and friends at two time points 10 years apart. At the second time point, participants completed a biological protocol in which indices of autonomic, hypothalamic-pituitary-adrenal axis, cardiovascular, inflammatory, and metabolic function were obtained and used to create an AL summary score. Generalized estimating equations were used to examine the associations among three aspects of social relationships – social support, social negativity, and frequency of social contact – and AL. RESULTS Higher levels of spouse negativity, family negativity, friend contact, and network level contact were each associated with higher AL, and higher levels of spouse support were associated with lower AL, independent of age, sociodemographic factors, and health covariates. Tests for age interactions suggested that friend support and network support were each associated with higher AL among older adults, but at younger ages there appeared to be no association between friend support and AL and a negative association between network support and AL. For network negativity, there was a marginal interaction such that network negativity was associated with higher AL among younger adults but there was no association among older adults. CONCLUSIONS These findings demonstrate that structural and functional aspects of the social environment are associated with AL, and extend previous work by demonstrating that these associations vary based on the type of relationship assessed and by age. PMID:24447186

Geographic Trajectories of Al-Qaida and Taliban Terrorist Groups in Pakistan

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Syed Manzar Abbas Zaidi

2010-01-01

Full Text Available Though Western analysts tend to mention al-Qaida and Taliban in Pakistan in the same context, the dynamics of their relationship are far more complex than a cursory examination would reveal. The context of this relationship is best understood within the overarching paradigm of militant activities of post 9/11 Taliban and al-Qaida remnants in Pakistan's tribal areas, where these groups flourish. The military struggle in Afghanistan has significantly influenced the formation of a loosely structured alQaida/Taliban "nexus" that was forged in Pakistan's Federally Administered Tribal Areas (FATA, particularly Waziristan. In order to survive the ongoing North Atlantic Treaty Organization (NATO military operations to flush them out, these groups rapidly devised a symbiotic strategy that characterizes al-Qaida's ability to subsume itself within the ranks of different militant organizations in Pakistan.

A TEM study of martensite habit planes and orientation relationships in Cu-Al-Ni shape memory alloys using a fast Δg-based method

International Nuclear Information System (INIS)

No, M.L.; Caillard, D.; San Juan, J.

2009-01-01

Shape memory alloys undergo a martensitic transformation, where thermomechanical properties are basically controlled by the austenite-martensite interphases, exhibiting complex orientation relationships and irrational habit planes. They are usually determined by the phenomenological theory. In this work an experimental study of nine different habit planes and orientation relationships is first realized. Then, an analysis of the interphases in the reciprocal space shows that they cannot be univocally determined by the usual two-dimensional edge-to-edge matching method. Finally, we propose a new method, based on the three-dimensional edge-to-edge matching of dense planes across the interface, to determine the habit planes and the orientation relationships. This method requires only one selected area diffraction pattern on the edge-on interface and a three-dimensional simulation of the reciprocal lattices of both structures. The habit planes determined on CuAlNi by this method agree with the values proposed by the phenomenological theory

Variación espacial y temporal en los contenidos de mercurio, plomo, cromo y materia orgánica en sedimento del complejo de humedales de Ayapel, Córdoba, noroccidente colombiano

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Alex Fernando Rúa Cardona

2013-01-01

Full Text Available Las planicies de inundación atlánticas colombianas están impactadas por la minería aurífera artesanal desarrollada durante las últimas décadas. Sin embargo, la contaminación local por mercurio ha sido comparada con niveles de acción de otras latitudes y no se han incluido otros metales de interés sanitario en las investigaciones. El presente estudio contribuyó al conocimiento de la respuesta geoquímica espacial inducida por el pulso hidrológico y la composición de materia orgánica (MO en el área de influencia del complejo de humedales de Ayapel. Se evaluó la distribución espacial y temporal de mercurio (Hg, plomo (Pb, cromo (Cr y MO en el sedimento reciente del complejo cenagoso de Ayapel y se contrastó con el nivel de referencia de contaminación local por Hg (0,032 μg g-1, Pb (2,39 μg g-1 y Cr (89,58 μg g-1 determinado en la Formación Betulia. Los rangos de los tres metales fueron: 0,008-0,117 μg Hg g-1; 1,090-11,870 μg Pb g-1 y 5,350- 93,430 μg Cr g-1. El Hg mostró la mayor variabilidad espacial (0,083 ± 0,064 μg g-1 y niveles superiores en el afluente del frente de explotación aurífera en la década del 80. En comparación con el nivel de referencia, el 91 % del sedimento reciente presentó enriquecimiento por Pb (6,376 ± 4,048 μg g-1 y el 66,6 % enriquecimiento por Hg. En contraste, el contenido de Cr fue relativamente bajo (96,325 ± 29,868 μg g-1 y presentó tendencia a disminuir de oriente a occidente. El sedimento fue predominantemente inorgánico, con porcentajes medios de cenizas de 88,154 ± 3,822 % y escasos niveles de MO (11,846 ± 3,822 %. Se presume el aumento en la movilidad del Hg debido a la alta tasa de respiración de MO en la zona central del espejo de agua principal de la ciénaga de Ayapel. La resuspensión y migración de sedimentos contaminados es facilitada por la inestabilidad térmica de la columna de agua influenciada por la acción del viento.

Atomistic simulation of solid solution hardening in Mg/Al alloys: Examination of composition scaling and thermo-mechanical relationships

International Nuclear Information System (INIS)

Yi, Peng; Cammarata, Robert C.; Falk, Michael L.

2016-01-01

Dislocation mobility in a solid solution was studied using atomistic simulations of an Mg/Al system. The critical resolved shear stress (CRSS) for the dislocations on the basal plane was calculated at temperatures from 0 K to 500 K with solute concentrations from 0 to 7 at%, and with four different strain rates. Solute hardening of the CRSS is decomposed into two contributions: one scales with c 2/3 , where c is the solute concentration, and the other scales with c 1 . The former was consistent with the Labusch model for local solute obstacles, and the latter was related to the athermal plateau stress due to the long range solute effect. A thermo-mechanical model was then used to analyze the temperature and strain rate dependences of the CRSS, and it yielded self-consistent and realistic results. The scaling laws were confirmed and the thermo-mechanical model was successfully parameterized using experimental measurements of the CRSS for Mg/Al alloys under quasi-static conditions. The predicted strain rate sensitivity from the experimental measurements of the CRSS is in reasonable agreement with separate mechanical tests. The concentration scaling and the thermo-mechanical relationships provide a potential tool to analytically relate the structural and thermodynamic parameters on the microscopic level with the macroscopic mechanical properties arising from dislocation mediated deformation.

Saturnismo: a propósito de un caso Lead poisoning: A case report

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Pablo Honorio Labanda Urbano

2012-06-01

Full Text Available Profesora de pintura sobre vidrio y restauración de vidrieras de 65 años acude a la Unidad Médica de Valoración de Incapacidades del Instituto Nacional de la Seguridad Social (INSS con diagnóstico de exposición laboral a plomo. La paciente ha permanecido en Incapacidad Temporal por astenia durante varios meses, y se le detecta tras una reincorporación al trabajo plumbemia elevada, asociada a otros síntomas típicos de la intoxicación por plomo, por lo que se la separa de su ambiente de trabajo. Finalmente, el Equipo de Valoración de Incapacidades, reunido para valorar su caso resuelve Incapacidad Laboral Permanente Total derivada de enfermedad profesional para trabajos en que haya exposición a plomo y otros ototóxicos, exposición a ruidos de riesgo, y para aquellos trabajos en que sea necesaria una comunicación verbal fluida en frecuencias conversacionales normales. Con este caso clínico pretendemos revisar los síntomas del cuadro clínico de saturnismo, así como hacer una reflexión sobre los efectos de la prevención de riesgos para el trabajador.Lead poisoning is most commonly caused by occupational exposure. We report a case of a 65-year-old woman, paint teacher, which was working in reparation of stained glass window. She consults the Medical Incapacity Valoration Unit of National Institute of Social Security with diagnosis of lead occupational intoxication. The patient was not able to word for several months because of presenting asthenia. After reporting for work high lead blood levels were detected, in association with physical symptoms. She was evaluated by a tribunal which settled total long sick-leave due to occupational lead exposure and was restricted for loud works and other ones that need verbal communication in conversational frequencies. With this clinical case we try to check the symptoms of lead poisoning, as well as to think about the effects of prevention of occupational hazards.

PRECIPITATION BEHAVIOR OF Co PHASES IN B2-ORDERED(Ni,Co)Al COMPOUND

Institute of Scientific and Technical Information of China (English)

W.H. Tian; A.L. Fan; M. Nemoto

2002-01-01

The precipitation behavior of Co phases in B2-ordered (Ni, Co)Al has been investigatedin terms of transmission electron microscopy. Fine precipitation off cc-Co occurs in(Ni, Co)Al by aging at temperature over 973K. The orientation relationship betweenthe fcc-Co precipitates and the B2-(Ni, Co)Al matrix follows the Kurdjumow-Sachs(K-S) orientation relation. But when the aging temperature is under 873K the Coprecipitates have a hcp crystal structure. The orientation relationship between thehcp-Co precipitates and the B2-(Ni, Co)Al matrix follows the Burgers orientation re-lation. (Ni, Co)Al is hardened appreciably by the fine precipitation of both the fcc-Coand hcp-Co phases. The temperature dependence of the yield strength of precipitate-containing B2-ordered (Ni, Co)Al was investigated by compression tests over the rangeof 298-1273K. The fine precipitation of Co phases enhances greatly the low and in-termediate temperature yield strength. When the deformation temperature was over873K, the strength of precipitate-containing (Ni, Co)Al is comparable to ternary dual-phase (Ni, Co)Al+Ni3Al alloy.

Microestructura y propiedades de materiales cerámicos PZT con control de crecimiento de grano

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Celi, L. A.

1999-10-01

Full Text Available Lead zirconate titanate ceramic powders have been surface modified by using phosphor esther 0.3% in volume. The phosphorous modification gave higher densities at lower temperatures associated with a reduction of the weight losses during the densification process. From the relationships between ceramic processing and microstructure, it was established that the phosphorous surface modification allows the effective grain growth control as well a higher homogeneity in the grain size distribution.

Se ha realizado un proceso de modificación superficial con ester fosfato al 0.3% en volumen, sobre polvo cerámico de titanato circonato de plomo, PZT. Se observa que el material modificado con fósforo presenta una mayor densificación aparente a una temperatura menor unida a una reducción de las pérdidas de peso durante el proceso de densificación. Se han establecido las relaciones entre el procesamiento y las microestructuras del material PZT sin modificar y el modificado. Se evidencia un control del crecimiento de grano y una mayor homogeneidad en la distribución de tamaños de grano en el material modificado.

Biosorción de Cd (II) y Pb (II) en columna de lecho fijo con cáscara de cacao

OpenAIRE

Vera, L.; Bermejo, D.; Uguña, M.F.; García, N.; Flores, M.; Brazales, D.

2018-01-01

En este trabajo se presentan los resultados de la biosorcion de Pb (II) y Cd (II) de aguas sintéticas con cáscara de cacao en columnas de lecho fijo. Los datos experimentales fueron ajustados a varios modelos que describen la curva de ruptura para sistemas monocomponentes y bicomponentes. Los porcentajes de remoción de plomo y cadmio en sistemas monocomponentes son 91% y 90% respectivamente. En sistemas bicomponentes Pb-Cd el porcentaje de remoción de plomo 88% y cadmio 90%. El modelo de Dosi...

The Relationship between Language Functions and Character Types in Noon val-Ghalam by Jalal Al Ahmad

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Sayyed Ahmad Parsa

2013-11-01

Full Text Available Abstract Making harmony among language functions of story characters with their character types is one of the characteristics and advantages of modern and successful story writing. In traditional fictional literature in Iran (prose and verse, this point is not considered important and story characters, generally, speak in the voice of narrator or writer since there is the narrators statement on their speech, they are not the representative of their class and character type. Not paying attention to this subject, causes disorder in either making supposition of reality or personifying, which are both important principals of story telling. This study views from this point the story of Noon val-Ghalam of Jalal Al Ahmad who is a contemporary writer. The methodology is qualitative, and data collection is based on content–analysis and document- analysis. As Al Ahmad was one of the Iranian contemporary writers and was familiar with western and Iranian writers, it is expected that the language and way of describing story characters he made, be based on their social classes. But this study, by stating different proofs, shows that this writer ignores the relationship necessary for language functions and character type among characters in the story and because of the imposition of his knowledge, statement and political and social view, the independence of the protagonists in his story is not well-considered.  The inflection of political and social thoughts of each writer among his works, is not a shortfall by itself, but representing of speeches in protagonists, in the way which is not in harmony with their characters, underestimates them as an instrument for specific social and political representatives. This not only displays the character like a personified ideas, but also distructs processing of fictional dialogue as an important element in storytelling . Since in each language people from different social groups, use almost the same vocabularies that

AL JAZEERA AND QATARI FOREIGN POLICY: A CRITICAL APPROACH

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Karim Pourhamzavi

2016-01-01

Full Text Available Our paper explores the Al-Jazeera network and its relationship to the state which set it up and continues to fund it.  We suggest that, while the network may provide perspectives for Western viewers that other large, but Western-owned networks do not, it is far from immune from the problems of state influence.  Behind a cultivated veneer of providing perspectives from 'the Arab street', the network reflects foreign policy perspectives of the Qatari state and the small elite which controls it.  This paper surveys Al-Jazeera Arabic news coverage (August 2014-August 2015 of conflict in Iraq and three AJA current affairs programmes coverage (January 2014-August 2015 of conflict in Iraq, Syria and Egypt.  The results indicate that, on foreign policy issues which the Qatari elite regards as particularly important, the network promotes the perspectives of the state.  The relationship between the Qatari state and Al-Jazeera also constrains the network's independence and objectivity.

Al-induced root cell wall chemical components differences of wheat ...

African Journals Online (AJOL)

Root growth is different in plants with different levels of Al-tolerance under Al stress. Cell wall chemical components of root tip cell are related to root growth. The aim of this study was to explore the relationship between root growth difference and cell wall chemical components. For this purpose, the cell wall chemical ...

Species delimitation and interspecific relationships of the genus Orychophragmus (Brassicaceae inferred from whole chloroplast genomes

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Huan Hu

2016-12-01

Full Text Available IntroductionIt is rather difficult to delimit recently diverged species and construct their interspecific relationships because of insufficient informative variations of sampled DNA fragments (Schluter, 2000; Arnold, 2006. The genome-scale sequence variations were found to increase the phylogenetic resolutions of both high- and low-taxonomic groups (e.g., Yoder et al., 2013; Lamichhaney et al., 2015. It is still expensive to collect nuclear genome variations between species for most none-model genera without the reference genome. However, chloroplast genomes (plastome are relatively easy to be assembled to examine interspecific relationships for phylogenetic analyses, especially in addressing unresolved relationship at low taxonomic levels (Wu et al., 2010; Nock et al., 2011; Yang et al., 2013; Huang et al., 2014; Carbonell-Caballero et al., 2015. Plastomes are haploid with maternal inheritance in most angiosperms (Corriveau and Coleman, 1988; Zhang and Liu, 2003; Hagemann, 2004 and are highly conservative in gene order and genome structure with rare recombinations (Jansen et al., 2007; Moore et al., 2010. In this study, we aimed to examine species delimitation and interspecific relationships in Orychophragmus through assembling chloroplast genomes of multiple individuals of tentatively delimited species (Hu et al., 2015a. Orychophragmus is a small genus in the mustard family (Brassicaceae, Cruciferae distributed in northern, central, and southeastern China (Zhou et al., 2001. Its plants have been widely cultivated as ornamentals, vegetables, or source of seed oil (Sun et al., 2011. Despite controversial species delimitations in the genus (Zhou et al., 1987; Tan et al., 1998; Wu and Zhao, 2003; Al-Shehbaz and Yang, 2000; Zhou et al., 2001; Sun et al., 2012, our recent study based on nuclear (nr ITS sequence variations suggested the recognition of seven species (Hu et al., 2015a. Orychophragmus is sister to Sinalliaria, which is a genus endemic

Sibling Relationships Cognition in Japanese Female University Students

Science.gov (United States)

Sawai, Misae; Kato, Daiki

2017-01-01

This study examined the factor structure of sibling relationships in Japanese female university students. Two hundred and fifteen Japanese female university students participated in this study. The Adult Sibling Relationship Scale (ASRQ, Stocker et al., 1997) was used to measure sibling relationship cognition. The model was constructed as a result…

More Questions than Answers: Continued Critical Reanalysis of Fredrickson et al.'s Studies of Genomics and Well-Being.

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Nicholas J L Brown

Full Text Available We critically re-examine Fredrickson et al.'s renewed claims concerning the differential relationship between hedonic and eudaimonic forms of well-being and gene expression, namely that people who experience a preponderance of eudaimonic well-being have gene expression profiles that are associated with more favorable health outcomes. By means of an extensive reanalysis of their data, we identify several discrepancies between what these authors claimed and what their data support; we further show that their different analysis models produce mutually contradictory results. We then show how Fredrickson et al.'s most recent article on this topic not only fails to adequately address our previously published concerns about their earlier related work, but also introduces significant further problems, including inconsistency in their hypotheses. Additionally, we demonstrate that regardless of which statistical model is used to analyze their data, Fredrickson et al.'s method can be highly sensitive to the inclusion (or exclusion of data from a single subject. We reiterate our previous conclusions, namely that there is no evidence that Fredrickson et al. have established a reliable empirical distinction between their two delineated forms of well-being, nor that eudaimonic well-being provides any overall health benefits over hedonic well-being.

The Ulama and the Al Saud: A Relationship Between Elites in Saudi Arabia

OpenAIRE

Permuy, Alexandra

2016-01-01

The origins of the Kingdom of Saudi Arabia date back to the alliance forged between the AlSaud and the preacher Muhammad Ibn AbdulWahhab in the 18th century, and the subsequent establishment of the first Saudi state. Since then, the religious scholars, or ulama, have played an important role that is still vital to the continued survival of the Saudi regime’s credentials. However, that role has changed overtime. Historically, the AlSaud and the ulama were elites of equal standing, but oil reso...

FEM modeling on the compaction of Fe and Al composite powders

Directory of Open Access Journals (Sweden)

Han P.

2015-01-01

Full Text Available The compaction process of Fe and Al composite powders subjected to single action die compaction was numerically modeled by FEM method. The relationship between the overall relative density and compaction pressure of the compacts with various Al contents was firstly identified, and the influences of Al content on the local relative density, stress, and their distributions were studied. Then the compaction pressure effects on the above properties with fixed Al content were discussed. Furthermore, detailed flow behaviors of the composite powders during compaction and the relationship between the compaction pressure and the ejection force/spring back of the compact were analyzed. The results show that: (1 With each compaction pressure, higher relative density can be realized with the increase of Al content and the relative density distribution tends to be uniform; (2 When the Al content is fixed, higher compaction pressure can lead to composite compact with higher relative density, and the equivalent Von Mises stress in the central part of the compact increases gradually; (3 Convective flow occurs at the top and bottom parts of the compact close to the die wall, each indicates a different flow behavior; (4 The larger the compaction pressure for each case, the higher the residual elasticity, and the larger the ejection force needed.

Effect of the addition of Al-Ti-C master alloy on the microstructure and microhardness of a cast Al-10Mg alloy

Institute of Scientific and Technical Information of China (English)

无

2006-01-01

The microstructure and microhardness of a cast Al-10wt%Mg (henceforth Al-l0Mg) alloy with 0.2wt% addition of Al-5Ti-0.25C master alloy were compared with those of a refiner-free alloy of similar chemical composition.It was found that this level of the master alloy addition not only caused an effective grain refinement, but also caused a significant increase in the microhardness of the Al-10Mg alloy.Microchemical analysis revealed that TiC particles existed in the grain center.The relationship between the holding time and grain size was also studied.It shows that the grain refining efficiency is faded observably with the holding time.This is explained in terms of the instability of TiC particles.

The Relationship between Language Functions and Character Types in Noon val-Ghalam by Jalal Al Ahmad

Directory of Open Access Journals (Sweden)

Sadi Haji

2013-10-01

Full Text Available Abstract Making harmony among language functions of story characters with their character types is one of the characteristics and advantages of modern and successful story writing. In traditional fictional literature in Iran (prose and verse, this point is not considered important and story characters, generally, speak in the voice of narrator or writer since there is the narrators statement on their speech, they are not the representative of their class and character type. Not paying attention to this subject, causes disorder in either making supposition of reality or personifying, which are both important principals of story telling. This study views from this point the story of Noon val-Ghalam of Jalal Al Ahmad who is a contemporary writer. The methodology is qualitative, and data collection is based on content–analysis and document- analysis. As Al Ahmad was one of the Iranian contemporary writers and was familiar with western and Iranian writers, it is expected that the language and way of describing story characters he made, be based on their social classes. But this study, by stating different proofs, shows that this writer ignores the relationship necessary for language functions and character type among characters in the story and because of the imposition of his knowledge, statement and political and social view, the independence of the protagonists in his story is not well-considered.  The inflection of political and social thoughts of each writer among his works, is not a shortfall by itself, but representing of speeches in protagonists, in the way which is not in harmony with their characters, underestimates them as an instrument for specific social and political representatives. This not only displays the character like a personified ideas, but also distructs processing of fictional dialogue as an important element in storytelling . Since in each language people from different social groups, use almost the same vocabularies

The influence of the sustainability agenda on buyer-supplier relationships

DEFF Research Database (Denmark)

Jørsfeldt, Liliyana Makarowa; Wæhrens, Brian Vejrum

2013-01-01

The positive effect of supplier-buyer relationships on supply chain performance has al-ready been supported by previous studies. Yet, little empirical research has explored how the sustainability agenda influences these relationships. Thus, this study investi-gates how supplier-buyer relationships...

length-weight relationship of hepsetus odoe in lapai - agaie ...

African Journals Online (AJOL)

Ibrahim Usman

biometric relationship so that data collected from the field can be transform into appropriate indices (Ecoutin et al., 2005). Length and weight are two useful parameters used especially in fisheries assessment. This relationship known as length-weight relationship (LWR), is commonly used in the analysis of fisheries data.

The relationship between Al and Si in biogenic silica as determined by PIXE and XAS

International Nuclear Information System (INIS)

Beck, L.; Gehlen, M.; Flank, A.-M.; Bennekom, A.J. van; Beusekom, J.E.E. van

2002-01-01

Biogenic silica, one of the major constituents of marine sediments, is a potentially powerful paleoceanographic tool, revealing information on past productivity. Interpreting the sedimentary records of the biogenic silica requires, however, an understanding of its preservation. Dissolution of biogenic silica is controlled by the presence of trace elements such as Al. The work in this paper focuses on the association of Al and Si in biogenic silica. The composition and the atomic structure of cultured and natural diatoms were determined by using PIXE and XAS techniques. This study provides the first evidence for a structural association of Al and Si in biogenic silica

Degradation of AlGaN/GaN High Electron Mobility Transistors with Different AlGaN Layer Thicknesses under Strong Electric Field

International Nuclear Information System (INIS)

Ling, Yang; Yue, Hao; Xiao-Hua, Ma; Jing-Jing, Ma; Cheng, Zhu

2010-01-01

The degradation of AlGaN/GaN high electron mobility transistors (HEMTs) has a close relationship with a model of traps in AlGaN barriers as a result of high electric field. We mainly discuss the impacts of strong electrical field on the AlGaN barrier thickness of AlGaN/GaN HEMTs. It is found that the device with a thin AlGaN barrier layer is more easily degraded. We study the degradation of four parameters, i.e. the gate series resistance R Gate , channel resistance R channel , gate current I G,off at V GS = −5 and V DS = 0.1 V, and drain current I D,max at V GS = 2 and V DS = 5 V. In addition, the degradation mechanisms of the device electrical parameters are also investigated in detail. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Ti2Al(C, N) Solid Solution Reinforcing TiAl-Based Composites: Evolution of a Core-Shell Structure, Interfaces, and Mechanical Properties.

Science.gov (United States)

Song, Xiaojie; Cui, Hongzhi; Han, Ye; Ding, Lei; Song, Qiang

2018-05-16

In this work, Ti 2 Al(C, N) solid solution with lamellar structure-enhanced TiAl matrix composites was synthesized by vacuum arc melting, using bulk g-C 3 N 4 , Ti, and Al powders as raw materials. The phases, microstructures, interfaces, and mechanical properties were investigated. MAX phase of Ti 2 Al(C, N) solid solution with lamellar structure was formed. During the melting process, first, C 3 N 4 reacted with Ti to form Ti(C, N) by Ti + C 3 N 4 → Ti(C, N). Then Ti 2 Al(C, N) was formed by a peritectic reaction of TiAl(l) + Ti(C, N)(s) → Ti 2 Al(C, N). C 3 N 4 is the single reactant that provides C and N simultaneously to final product of Ti 2 Al(C, N). The interfaces of TiAl//Ti 2 Al(C, N) and Ti 2 Al(C, N)//Ti(C, N) display perfect orientation relationships with low misfit values. The microhardness, compressive strength, and strain of best-performing TiAl-10 mol % Ti 2 Al(C, N) composite were improved by 45%, 55.7%, and 50% compared with the TiAl alloy, respectively. Uniformly distributed Ti 2 Al(C, N) and unreacted Ti(C, N) particles contributed to the grain refinement and reinforcement of the TiAl matrix. Laminated tearing, particle pull-out, and the crack-arresting of Ti 2 Al(C, N) are crucial for the improvement in compressive strength and plasticity of the composites.

Comparative study of phase structure and dielectric properties for K0.5Bi0.5TiO3-BiAlO3 and LaAlO3-BiAlO3

International Nuclear Information System (INIS)

Hou, Yudong; Zheng, Mupeng; Si, Meiju; Cui, Lei; Zhu, Mankang; Yan, Hui

2013-01-01

In this work, two perovskite-type compounds, K 0.5 Bi 0.5 TiO 3 and LaAlO 3 , have been selected as host material to incorporate with BiAlO 3 using a solid-state reaction route. The phase evolution and dielectric properties for both systems have been investigated in detail. For the K 0.5 Bi 0.5 TiO 3 -BiAlO 3 system, it is interesting to find that when using Bi 2 O 3 , Al 2 O 3 , K 2 CO 3 , and TiO 2 as starting materials, the formed compounds are K 0.5 Bi 0.5 TiO 3 -K 0.5 Bi 4.5 Ti 4 O 15 and Al 2 O 3 only plays a dopant role. There are two distinct dielectric peaks appearing in the patterns of temperature dependence of dielectric constant, corresponding to the phase-transition points of perovskite-type K 0.5 Bi 0.5 TiO 3 and Aurivillius-type K 0.5 Bi 4.5 Ti 4 O 15 , independently. In comparison, using Bi 2 O 3 , Al 2 O 3 , and La 2 O 3 as starting materials, the pure perovskite phase LaAlO 3 -BiAlO 3 can be obtained. Compared to the inherent paraelectric behavior in LaAlO 3 , the diffuse phase-transition phenomena can be observed in the LaAlO 3 -BiAlO 3 binary system, which corresponds well to the Vogel-Fulcher (VF) relationship. Moreover, compared to pure LaAlO 3 , the synthesized LaAlO 3 -BiAlO 3 compound shows enhanced dielectric properties, which are promising in application as gate dielectric materials. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

High-pressure modifications of CaZn2, SrZn2, SrAl2, and BaAl2: Implications for Laves phase structural trends

International Nuclear Information System (INIS)

Kal, Subhadeep; Stoyanov, Emil; Belieres, Jean-Philippe; Groy, Thomas L.; Norrestam, Rolf; Haeussermann, Ulrich

2008-01-01

High-pressure forms of intermetallic compounds with the composition CaZn 2 , SrZn 2 , SrAl 2 , and BaAl 2 were synthesized from CeCu 2 -type precursors (CaZn 2 , SrZn 2 , SrAl 2 ) and Ba 21 Al 40 by multi-anvil techniques and investigated by X-ray powder diffraction (SrAl 2 and BaAl 2 ), X-ray single-crystal diffraction (CaZn 2 ), and electron microscopy (SrZn 2 ). Their structures correspond to that of Laves phases. Whereas the dialuminides crystallize in the cubic MgCu 2 (C15) structure, the dizincides adopt the hexagonal MgZn 2 (C14) structure. This trend is in agreement with the structural relationship displayed by sp bonded Laves phase systems at ambient conditions. - Graphical abstract: CeCu 2 -type polar intermetallics can be transformed to Laves phases upon simultaneous application of pressure and temperature. The observed structures are controlled by the valence electron concentration

A reply to Iversen et al.'s comment “Monitoring of animal abundance by environmental DNA - An increasingly obscure perspective”

Science.gov (United States)

Klymus, Katy E.; Richter, Catherine A.; Chapman, Duane C.; Paukert, Craig

2015-01-01

We appreciate the conversation put forward by Iversen et al. (2015) in their response to our article “Quantification of eDNA shedding rates from invasive bighead carp Hypophthalmichthys nobilis and silver carp Hypophthalmichthys molitrix” in the 2015 environmental DNA special issue of Biological Conservation.We agree with Iversen et al.'s concern about overly optimistic conclusions that could be drawn from the current eDNA literature. One hope for eDNA technology is that it can be used in estimating abundance or population density. Evidence suggests that eDNA measurements correlate with total biomass (Takahara et al., 2012) rather than abundance. We demonstrate a similar relationship between biomass and eDNA shedding rates. Nevertheless, without field testing of these methods and specific survey protocols, we cannot make strong conclusions regarding the technique's field applicability. In our manuscript, we attempted to point out areas in which more research is needed.

26Al in the interstellar medium

International Nuclear Information System (INIS)

Clayton, D.D.; Leising, M.D.

1987-01-01

Several different lines of physical reasoning have converged on the importance of the radioactive nucleus 26 Al. The sciences of meteoritics, nucleosynthesis, gamma-ray astronomy, galactic chemical evolution, solar system formation, and interstellar chemistry all place this nucleus in a central position with possible profound implications. Perhaps more importantly the study of this radioactivity can unite these diverse fields in a complicated framework which will benefit all of them. This review traces the evolution of ideas concerning 26 Al in the context of these disciplines. 26 Al was first discussed for the possibility that its decay energy could melt meteorite parent bodies, and its daughter, 26 Mg, was later found in meteorites with enhanced abundance. It was also among the first radioactivities expected to be synthesized in interestingly large quantities in nulceosynthetic events. The first definitive detection of gamma-rays from an interstellar radioactivity is that of 1.809 MeV gamma-rays from 26 Al. This discovery has many implications, some of which are outlined here. The whole problem of isotopic anomalies in meteorites is greatly influenced by the specific issues surrounding excess 26 Mg, whether it represents in situ decay of 26 Al or memory of conditions of the ISM. The relationships among these ideas and their implications are examined. (orig.)

Fabrication-process-induced variations of Nb/Al/AlOx/Nb Josephson junctions in superconductor integrated circuits

International Nuclear Information System (INIS)

Tolpygo, Sergey K; Amparo, Denis

2010-01-01

Currently, superconductor digital integrated circuits fabricated at HYPRES, Inc. can operate at clock frequencies approaching 40 GHz. The circuits present multilayered structures containing tens of thousands of Nb/Al/AlO x /Nb Josephson junctions (JJs) of various sizes interconnected by four Nb wiring layers, resistors, and other circuit elements. In order to be fully operational, the integrated circuits should be fabricated such that the critical currents of the JJs are within the tight design margins and the proper relationships between the critical currents of JJs of different sizes are preserved. We present experimental data and discuss mechanisms of process-induced variations of the critical current and energy gap of Nb/Al/AlO x /Nb JJs in integrated circuits. We demonstrate that the Josephson critical current may depend on the type and area of circuit elements connected to the junction, on the circuit pattern, and on the step in the fabrication process at which the connection is made. In particular, we discuss the influence of (a) the junction base electrode connection to the ground plane, (b) the junction counter electrode connection to the ground plane, and (c) the counter electrode connection to the Ti/Au or Ti/Pd/Au contact pads by Nb wiring. We show that the process-induced changes of the properties of Nb/Al/AlO x /Nb junctions are caused by migration of impurity atoms (hydrogen) between the different layers comprising the integrated circuits.

Kinematics of Disease Progression in Bulbar ALS

Science.gov (United States)

Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne

2010-01-01

The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…

Grain refinement efficiency and mechanism of aluminium carbide in Mg-Al alloys

International Nuclear Information System (INIS)

Lu, L.; Dahle, A.K.; StJohn, D.H.

2005-01-01

Detailed microscopic examination using optical and electron microscopes suggests that Al 4 C 3 , often observed in the central regions of magnesium grains on polished sections, is a potent substrate for primary Mg. Calculations of the crystallographic relationships between magnesium and Al 4 C 3 further support the experimental observations

Local heteroepitaxy as an adhesion mechanism in aluminium coatings cold gas sprayed on AlN substrates

International Nuclear Information System (INIS)

Wüstefeld, Christina; Rafaja, David; Motylenko, Mykhaylo; Ullrich, Christiane; Drehmann, Rico; Grund, Thomas; Lampke, Thomas; Wielage, Bernhard

2017-01-01

Cold gas sprayed Al coatings deposited onto wurtzitic AlN substrates show excellent adhesion. As a possible adhesion mechanism, the local heteroepitaxy between Al and AlN was considered and verified experimentally in Al coatings, which were deposited using magnetron sputtering or cold gas spraying on single-crystalline and polycrystalline AlN substrates. Analysis of the local orientation relationships at the Al/AlN interfaces revealed that preferentially such lattice planes of Al align parallel with the upright lattice planes of AlN, which possess similar interplanar distances. The matching lattice planes in the Al coatings grew as continuations of the lattice planes in the AlN substrates. In all samples under study, the parallel alignment of the lattice planes {220}_A_l and {110}_A_l_N was found. Additional orientation relationships between Al and AlN arose if parallel lattice planes with similar interplanar spacing could be found in both counterparts via rotation of the lattice planes {220}_A_l around their normal direction. Still, the oriented growth of Al on AlN is only possible if Al atoms in the deposited coatings are mobile enough to rearrange along the AlN surface. Whereas the mobility of Al atoms in a magnetron sputtering process is expected to be sufficiently high, the intrinsic mobility of Al atoms in the cold gas sprayed particles is anticipated to be low. However, the auxiliary microstructure analyses have shown that local recrystallization and partial melting are two phenomena, which can facilitate the rearrangement of Al atoms within the cold gas sprayed coating.

Unexpected Relationships and Inbreeding in HapMap Phase III Populations

Science.gov (United States)

Stevens, Eric L.; Baugher, Joseph D.; Shirley, Matthew D.; Frelin, Laurence P.; Pevsner, Jonathan

2012-01-01

Correct annotation of the genetic relationships between samples is essential for population genomic studies, which could be biased by errors or omissions. To this end, we used identity-by-state (IBS) and identity-by-descent (IBD) methods to assess genetic relatedness of individuals within HapMap phase III data. We analyzed data from 1,397 individuals across 11 ethnic populations. Our results support previous studies (Pemberton et al., 2010; Kyriazopoulou-Panagiotopoulou et al., 2011) assessing unknown relatedness present within this population. Additionally, we present evidence for 1,657 novel pairwise relationships across 9 populations. Surprisingly, significant Cotterman's coefficients of relatedness K1 (IBD1) values were detected between pairs of known parents. Furthermore, significant K2 (IBD2) values were detected in 32 previously annotated parent-child relationships. Consistent with a hypothesis of inbreeding, regions of homozygosity (ROH) were identified in the offspring of related parents, of which a subset overlapped those reported in previous studies (Gibson et al. 2010; Johnson et al. 2011). In total, we inferred 28 inbred individuals with ROH that overlapped areas of relatedness between the parents and/or IBD2 sharing at a different genomic locus between a child and a parent. Finally, 8 previously annotated parent-child relationships had unexpected K0 (IBD0) values (resulting from a chromosomal abnormality or genotype error), and 10 previously annotated second-degree relationships along with 38 other novel pairwise relationships had unexpected IBD2 (indicating two separate paths of recent ancestry). These newly described types of relatedness may impact the outcome of previous studies and should inform the design of future studies relying on the HapMap Phase III resource. PMID:23185369

Microstructure/Oxidation/Microhardness Correlations in Gamma-Based and Tau-Based Al-Ti-Cr Alloys

Science.gov (United States)

Brady, Michael P.; Smialek, J. L.; Humphrey, D. L.

1994-01-01

The relationships between alloy microstructure and air oxidation kinetics and alloy microstructure and microhardness in the Al-Ti-Cr system for exposures at 800 C and 1000 C were investigated. The relevant phases were identified as tau (Ll2), gamma (LIO), r-Al2Ti, TiCrAl (laves), and Cr2AI. Protective alumina formation was associated with tau, Al-rich TiCrAl, and gamma/TiCrAl mixtures. Brittleness was associated with the TiCrAl phase and tau decomposition to A12Ti + Cr2AI. It was concluded that two-phase gamma + TiCrAl alloys offer the greatest potential for oxidation resistance and room temperature ductility in the Al-Ti-Cr system.

Presencia de metales pesados en cultivo de cacao (Theobroma cacao L. orgánico

Directory of Open Access Journals (Sweden)

Hugo Alfredo Huamaní-Yupanqui

2012-12-01

Full Text Available La presencia de metales pesados en el cultivo de cacao (Theobroma cacao L. es actualmente un grave problema para agricultores y cooperativas de las regiones Huánuco y Ucayali, Perú. En el presente trabajo se evaluaron los contenidos de cadmio y plomo en suelos y hojas del cacao en estas regiones. Para el efecto se recolectaron y analizaron en laboratorio muestras tomadas en 22 parcelas con cultivos orgánicos de esta especie, 17 en la región Huánuco y cinco en la región Ucayali. Se realizaron análisis de correlación de Pearson entre los contenidos de plomo y cadmio disponibles en el suelo con variables foliares (P, Mg, Ca, Zn, Cd, Pb y del suelo (arena, arcilla y K. En los suelos, sólo en el caso de potasio se presentan deficiencias; mientras que en el tejido foliar se presentaron deficiencias de N, P, K, Mg y Zn. Los valores promedio de cadmio y plomo disponible en los suelos fueron 0.53 y 3.02 ppm y en las hojas de cacao de 0.21 y 0.58 ppm respectivamente.

Experimental determination of the phase relationships in Zr/2.5 8.0 at% Nb/0 6.7 at% Al alloys with 750 at ppm 0 and 250 at ppm N between 730 900° C

Science.gov (United States)

Peruzzi, A.; Bolcich, J.

1990-11-01

Zr alloys with 2.5 to 8.0 at% Nb and 0 to 6.7 at% Al were subjected to dynamic and static treatments between 730-900° C and studied by qualitative and quantitative optical metallography, electrical resistance, X-ray diffractometry and electron microanalysis. The experimental data were analyzed by taking into account the effects of oxygen and nitrogen impurities. The main results for Zn-Nb-Al alloys with 750 at ppm O and 250 at ppm N are the following: (i) Equilibrium relationships are established between the α (hcp), β (bcc) and Zr 3Al (Cu 3Au) phases along isothermal sections at 730, 771 and 800°C. (ii) The β/ α + β boundaries are determined along iso-aluminum vertical sections at 6.7, 3.3 and 0 at% Al. (iii) The addition of Al to Zr-Nb alloys increases the solubility of Nb in the α phase, its maximum value at 730° C being about 0.7-0.8 at% for 4 at% Al. (iv) Solubility values for Al in the α-phase of Zr-Al were estimated by extrapolation from ternary alloys. These estimates help to solve an existing discrepancy in the Zr-Al system.

Experimental determination of the phase relationships in Zr/2.5-8.0 at% Nb/0-6.7 at% Al alloys with 750 at ppm O and 250 at ppm N between 730-900deg C

International Nuclear Information System (INIS)

Peruzzi, A.; Bolcich, J.

1990-01-01

Zr alloys with 2.5 to 8.0 at% Nb and 0 to 6.7 at% Al were subjected to dynamic and static treatments between 730-900deg C and studied by qualitative and quantitative optical metallography, electrical resistance, X-ray diffractometry and electron microanalysis. The experimental data were analyzed by taking into account the effects of oxygen and nitrogen impurities. The main results for Zn-Nb-Al alloys with 750 atppm O and 250 atppm N are the following: (i) Equilibrium relationships are established between the α (hcp), β (bcc) and Zr 3 Al (Cu 3 Au) phases along isothermal sections at 730, 771 and 800deg C. (ii) The β/α+β boundaries are determined along iso-aluminum vertical sections at 6.7, 3.3 and 0 at% Al. (iii) The addition of Al to Zr-Nb alloys increases the solubility of Nb in the α phase, its maximum value at 730deg C being about 0.7-0.8 at% for 4 at% Al.(iv) Solubility values for Al in the α-phase of Zr-Al were estimated by extrapolation from ternary alloys. These estimates help to solve an existing discrepancy in the Zr-Al system. (orig.)

Spanish lead at the beginning of the 20th century: a competitiveness analysis based on records from the Crédit Lyonnais bank

OpenAIRE

Escudero, Antonio; Sánchez Picón, Andrés

2018-01-01

La documentación que hemos descubierto en el archivo histórico del Crédit Lyonnais de París posibilita estimar los costes de las fábricas españolas de plomo a principios del siglo xx, lo que permite profundizar en el éxito de Peñarroya y en el declive de los distritos de la Sierra de Cartagena y Linares. Esa misma documentación posee además un valor añadido, ya que informa sobre las razones por las que sobrevivían las fundiciones de los viejos distritos: altos precios del plomo metal en...

Improved phylogenomic taxon sampling noticeably affects nonbilaterian relationships.

Science.gov (United States)

Pick, K S; Philippe, H; Schreiber, F; Erpenbeck, D; Jackson, D J; Wrede, P; Wiens, M; Alié, A; Morgenstern, B; Manuel, M; Wörheide, G

2010-09-01

Despite expanding data sets and advances in phylogenomic methods, deep-level metazoan relationships remain highly controversial. Recent phylogenomic analyses depart from classical concepts in recovering ctenophores as the earliest branching metazoan taxon and propose a sister-group relationship between sponges and cnidarians (e.g., Dunn CW, Hejnol A, Matus DQ, et al. (18 co-authors). 2008. Broad phylogenomic sampling improves resolution of the animal tree of life. Nature 452:745-749). Here, we argue that these results are artifacts stemming from insufficient taxon sampling and long-branch attraction (LBA). By increasing taxon sampling from previously unsampled nonbilaterians and using an identical gene set to that reported by Dunn et al., we recover monophyletic Porifera as the sister group to all other Metazoa. This suggests that the basal position of the fast-evolving Ctenophora proposed by Dunn et al. was due to LBA and that broad taxon sampling is of fundamental importance to metazoan phylogenomic analyses. Additionally, saturation in the Dunn et al. character set is comparatively high, possibly contributing to the poor support for some nonbilaterian nodes.

Epitaxial growth of AlN on single crystal Mo substrates

International Nuclear Information System (INIS)

Okamoto, Koichiro; Inoue, Shigeru; Nakano, Takayuki; Kim, Tae-Won; Oshima, Masaharu; Fujioka, Hiroshi

2008-01-01

We have grown AlN films on single-crystalline Mo(110), (100), and (111) substrates using a low temperature pulsed laser deposition (PLD) growth technique and investigated their structural properties. Although c-axis oriented AlN films grow on Mo(100), the films contain 30 o rotated domains due to the difference in the rotational symmetry between AlN(0001) and Mo(100). AlN films with only poor crystalline quality grow on Mo(111) substrates, probably due to the poor surface morphology and high reactivity of the substrates. On the other hand, single crystal AlN films grow epitaxially on Mo(110) substrates with an in-plane relationship of AlN[11-20] // Mo[001]. Reflection high-energy electron diffraction or electron backscattered diffraction analysis has revealed that neither in-plane 30 deg. rotated domains nor cubic phase domains exist in the AlN films. X-ray reflectivity measurements have revealed that the heterointerface between AlN and Mo prepared by PLD at 450 deg. C is quite abrupt. These results indicate that PLD epitaxial growth of AlN on single crystal Mo substrates is quite promising for the fabrication of future high frequency filter devices

Epitaxial growth of AlN on single crystal Mo substrates

Energy Technology Data Exchange (ETDEWEB)

Okamoto, Koichiro; Inoue, Shigeru [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505 (Japan); Nakano, Takayuki; Kim, Tae-Won [Kanagawa Academy of Science and Technology (KAST) KSP east 301, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012 (Japan); Oshima, Masaharu [Department of Applied Chemistry, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656 (Japan); Fujioka, Hiroshi [Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505 (Japan); Kanagawa Academy of Science and Technology (KAST) KSP east 301, 3-2-1 Sakado, Takatsu-ku, Kawasaki, Kanagawa, 213-0012 (Japan)], E-mail: hfujioka@iis.u-tokyo.ac.jp

2008-06-02

We have grown AlN films on single-crystalline Mo(110), (100), and (111) substrates using a low temperature pulsed laser deposition (PLD) growth technique and investigated their structural properties. Although c-axis oriented AlN films grow on Mo(100), the films contain 30{sup o} rotated domains due to the difference in the rotational symmetry between AlN(0001) and Mo(100). AlN films with only poor crystalline quality grow on Mo(111) substrates, probably due to the poor surface morphology and high reactivity of the substrates. On the other hand, single crystal AlN films grow epitaxially on Mo(110) substrates with an in-plane relationship of AlN[11-20] // Mo[001]. Reflection high-energy electron diffraction or electron backscattered diffraction analysis has revealed that neither in-plane 30 deg. rotated domains nor cubic phase domains exist in the AlN films. X-ray reflectivity measurements have revealed that the heterointerface between AlN and Mo prepared by PLD at 450 deg. C is quite abrupt. These results indicate that PLD epitaxial growth of AlN on single crystal Mo substrates is quite promising for the fabrication of future high frequency filter devices.

Relationship between microstructure, cytotoxicity and corrosion properties of a Cu-Al-Ni shape memory alloy.

Science.gov (United States)

Colić, Miodrag; Rudolf, Rebeka; Stamenković, Dragoslav; Anzel, Ivan; Vucević, Dragana; Jenko, Monika; Lazić, Vojkan; Lojen, Gorazd

2010-01-01

Cu-Al-Ni shape memory alloys (SMAs) have been investigated as materials for medical devices, but their biomedical application is still limited. The aim of this work was to compare the microstructure, corrosion and cytotoxicity in vitro of a Cu-Al-Ni SMA. Rapidly solidified (RS) thin ribbons, manufactured via melt spinning, were used for the tests. The control alloy was a permanent mould casting of the same composition, but without shape memory effect. The results show that RS ribbons are significantly more resistant to corrosion compared with the control alloy, as judged by the lesser release of Cu and Ni into the conditioning medium. These results correlate with the finding that RS ribbons were not cytotoxic to L929 mouse fibroblasts and rat thymocytes. In addition, the RS ribbon conditioning medium inhibited cellular proliferation and IL-2 production by activated rat splenocytes to a much lesser extent. The inhibitory effects were almost completely abolished by conditioning the RS ribbons in culture medium for 4 weeks. Microstructural analysis showed that RS ribbons are martensitic, with boron particles as a minor phase. In contrast, the control Cu-Al-Ni alloy had a complex multiphase microstructure. Examination of the alloy surfaces after conditioning by energy dispersive X-ray and Auger electron spectroscopy showed the formation of Cu and Al oxide layers and confirmed that the metals in RS ribbons are less susceptible to oxidation and corrosion compared with the control alloy. In conclusion, these results suggest that rapid solidification significantly improves the corrosion stability and biocompatibility in vitro of Cu-Al-Ni SMA ribbons.

Al-Qurû’ fi Al-Qur’an ‘Inda Al-Anbary fi Al-Adhdâd

Directory of Open Access Journals (Sweden)

Raushani Azza

2018-03-01

Full Text Available This study examines about the term al-Qurû in the Qur’an. Al-Qurû is one of the most popular discussions among muslim scholars and mufasir, both in terms of language and fiqh. However, there is a bate among muslim scholar and mufasir about the meaning of al-Qurû. It’s because al-Qurû is one of the sentence of al-Adhdâd wich has two meaning, especially in the Qur’an, namely haid (menstruation and thahr. One of the most popular muslim scholar who concern in Qur’an and Arabic is al-Anbari with his book al-Adhdâd. Al-Anbari explains that Qurû has two meanings, First, al-Qurû in etymology is the form of Jama’ from aqra and qurû. Second, al-Qurû has a meaning of menstruation, thahr, or the period of iddah as a sign of being allowed to remarry after certain period of time.

Desarrollo de un plan de intervención integral para reducir la exposición al plomo y otros contaminantes en el centro minero de la Oroya, perú

OpenAIRE

Instituto Nacional de Salud

2005-01-01

Fuente: Centros de Control y Prevención de Enfermedades; Centro Nacional para la Salud Ambiental; Agencia para el Registro de Sustancias Tóxicas y Enfermedades. USAID Misión Perú. La Oroya, Perú es la sede de una fundición de metales que ha estado funcionado por más de 80 años. En octubre de 2003, la Agencia para el Desarrollo Internacional del gobierno de los Estados Unidos (U.S. Agency for Internacional Development, USAID) le pidió al Centro para el control y la Prevención de Enfermedade...

The relationship between rumination, PTSD, and depression symptoms.

Science.gov (United States)

Roley, Michelle E; Claycomb, Meredith A; Contractor, Ateka A; Dranger, Paula; Armour, Cherie; Elhai, Jon D

2015-07-15

Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are highly comorbid (Elhai et al., 2008. J. Clin. Psychiatry, 69, (4), 597-602). Rumination is a cognitive mechanism found to exacerbate and maintain both PTSD and MDD (Elwood et al., 2009. Clin. Psychol. Rev. 29, (1), 87-100; Olatunji et al., 2013. Clin. Psychol.: Sci. Pract. 20, (3), 225-257). Assess whether four rumination subtypes moderate the relationship between comorbid PTSD and MDD symptoms. We consecutively sampled patients (N=45) presenting to a mental health clinic using self-report measures of PTSD and MDD symptoms, and rumination in a cross-sectional design. Repetitive rumination moderates the relationship between PTSD and MDD symptoms at one standard deviation above the mean (β=.044, p=.016), while anticipatory rumination moderates the relationship between PTSD and MDD symptoms at mean levels and higher levels of anticipatory rumination (mean β=.030, p=.042; higher β=.060, p=.008). Repetitive and anticipatory rumination should be assessed in the context of comorbid PTSD and MDD and interventions should focus on reducing these rumination subtypes. Results should be replicated with other trauma populations because the number and complexity of traumatic events may impact the assessed symptoms. Constructs should also be assessed longitudinally, in order to establish causality. We are unable to confirm why rumination styles moderated the relationship between PTSD and depression or why counterfactual thinking and problem-focused thinking did not moderate the relationship between the two constructs. Copyright © 2015 Elsevier B.V. All rights reserved.

Al-Âyah al-Mutasyâbihât al-Lafzhiyyah fi Sûrah al-An’âm ‘Inda al-Kirmâny

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Hikmatiar Pasya

2017-07-01

Full Text Available This paper discusses about the verses of mutasyâbihât in the Quran. The debate of this verses caused various opinions. The meaning of the mutasyâbihât in this paper is the similarity and difference of the words in the Qur'an. Mufasir have different opinion about the meaning of the verse of mutasyâbihât al-lafdzi. In addition, many Hufadz of the Quran who are confused from one verse to another, or one chapter to another. It’s because similarity of verses in the Qur'an with other verses. So the writer wants to explain the verses mutasyâbihât al-lafdzi in the perspective of Hamzh al-Karmani in Surah al-An'âm. In this discussion the author discovers some passages in mutasyâbihât al-lafdzi, namely Asrâru al-balaghah fi mutasyabih al-lafdzi, Asrar al-balaghah fi mutasyabih al-hurf, and murâ'ah al-ikhtilâfmurâd bi al-lafdzi al-mukarrar.

THE MEDIATING ROLE OF ROMANTIC RELATIONSHIPS BETWEEN OPTIMISM AND DEPRESSION IN EMERGING ADULTS

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Elena Cattelino

2014-04-01

Full Text Available The existing literature showed that higher depression is linked to less optimism and to poor quality of romantic relationship, but studies considering the role of both optimism and romantic relationship on depression among emerging adults are lacking. The aims of the study were: 1 to describe the quality of romantic relationship, optimism and depression in a group of Italian emerging adults; 2 to examine the relation between optimism and depression; 3 to investigate the possible mediating role of quality of romantic relationship on the relation between optimism and depression. The study involved 228 emerging adults (59% girls, aged from 18 to 22 (mean age= 19.5, standard deviation=1.2. Optimism was assessed through the Life Orientation Test-Revised (LOT-R; Scheier et al., 1994, depression through the Center for Epidemiologic Studies Short Depression Scale (CES-D 10; Andresen et al., 1994 and quality of romantic relationships through the Romance Qualities Scale (RQS; Ponti et al., 2010. Main results showed a partial mediating effect of quality of romantic relationship between optimism and depression: less optimistic emerging adults reported higher depression, but the effect of lack of optimism was mediated by a good relationship with the partner. Implications for theory and practice were discussed.

Weight-length Relationships, Gonadosomatic Indeces, Sex Ratios and Relative Weight of the Omani-Indian Oil sardine, Sardinella longiceps (Valenciennes1847) from Al-Seeb Area; Sultanate of Oman

OpenAIRE

Al-Jufaili Saud

2011-01-01

This study presents the weight-length relationship and spawning period of the Omani Indian Oil sardine Sardinella longiceps (Valenciennes 1847) which inhabits the near shore zone along the Omani coast. A total of 1744 specimens were collected between January 1997 to February 1998 from Al-Seeb; a suburban area situated by the sea in Muscat, Oman. Samples were obtained on a monthly basis from beach seine and gillnet catches. The female to male sex ratio was obtained to be 0.6. The monthly varia...

Al-Mawardi dan Konsep Kenegaraan dalam Islam

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Rashda Diana

2017-05-01

Full Text Available Al-Mawardi was known as the first Moslem thinker of political theory in 11th century AD, five centuries before westerc scholars found their polical concept. Al-Mawardi’s concept of nation put religion in the centre of legitimacy source for political reality. He tried to compromise the political reality with the ideal of politics based on the law of religion and to make the religion as a justification way for political appropriateness. He said that leadership of nation would be an instrument to transmit prophetic mission in order to maintain the religion and to control the world. Meanwhile, al-Mawardi preferred institutional approach to manage a nation. He intensified the institutional function maximally and stabilized nation’s structure. His idea is surely interesting which is used by modern society today. They call it by social contract theory which means to make relationship between Ahl al-Ikhtiyâr dan Ahl al-Imâmah, that led rights and obligation to each others. If the khalîfah or the imâm wants to be obeyed by his people and asking their loyalty, he has to fulfil his duties such as protecting them and managing their concerns with full responsibility. Therefore, al-Mawardi is one of Moslem thinker of Islamic politics in the medieval who considers that the head of nation could be or changed if he does not have capability anymore to fulfil his duty. Then, the author of this article conclude that al-Mawardi’s theory could be an antithesis of the failed democracy theory.

Prediction of U-Mo dispersion nuclear fuels with Al-Si alloy using artificial neural network

International Nuclear Information System (INIS)

Susmikanti, Mike; Sulistyo, Jos

2014-01-01

Dispersion nuclear fuels, consisting of U-Mo particles dispersed in an Al-Si matrix, are being developed as fuel for research reactors. The equilibrium relationship for a mixture component can be expressed in the phase diagram. It is important to analyze whether a mixture component is in equilibrium phase or another phase. The purpose of this research it is needed to built the model of the phase diagram, so the mixture component is in the stable or melting condition. Artificial neural network (ANN) is a modeling tool for processes involving multivariable non-linear relationships. The objective of the present work is to develop code based on artificial neural network models of system equilibrium relationship of U-Mo in Al-Si matrix. This model can be used for prediction of type of resulting mixture, and whether the point is on the equilibrium phase or in another phase region. The equilibrium model data for prediction and modeling generated from experimentally data. The artificial neural network with resilient backpropagation method was chosen to predict the dispersion of nuclear fuels U-Mo in Al-Si matrix. This developed code was built with some function in MATLAB. For simulations using ANN, the Levenberg-Marquardt method was also used for optimization. The artificial neural network is able to predict the equilibrium phase or in the phase region. The develop code based on artificial neural network models was built, for analyze equilibrium relationship of U-Mo in Al-Si matrix

Lattice stabilities, mechanical and thermodynamic properties of Al3Tm and Al3Lu intermetallics under high pressure from first-principles calculations

Science.gov (United States)

Xu-Dong, Zhang; Wei, Jiang

2016-02-01

The effects of high pressure on lattice stability, mechanical and thermodynamic properties of L12 structure Al3Tm and Al3Lu are studied by first-principles calculations within the VASP code. The phonon dispersion curves and density of phonon states are calculated by using the PHONONPY code. Our results agree well with the available experimental and theoretical values. The vibrational properties indicate that Al3Tm and Al3Lu keep their dynamical stabilities in L12 structure up to 100 GPa. The elastic properties and Debye temperatures for Al3Tm and Al3Lu increase with the increase of pressure. The mechanical anisotropic properties are discussed by using anisotropic indices AG, AU, AZ, and the three-dimensional (3D) curved surface of Young’s modulus. The calculated results show that Al3Tm and Al3Lu are both isotropic at 0 GPa and anisotropic under high pressure. In the present work, the sound velocities in different directions for Al3Tm and Al3Lu are also predicted under high pressure. We also calculate the thermodynamic properties and provide the relationships between thermal parameters and temperature/pressure. These results can provide theoretical support for further experimental work and industrial applications. Project supported by the Scientific Technology Plan of the Educational Department of Liaoning Province and Liaoning Innovative Research Team in University, China (Grant No. LT2014004) and the Program for the Young Teacher Cultivation Fund of Shenyang University of Technology, China (Grant No. 005612).

Diffusion-induced quadrupole relaxation of 27Al nuclei in dilute Al-Ti, Al-Cr, Al-Mn, and Al-Cu alloys at high temperatures

International Nuclear Information System (INIS)

Bottyan, L.; Beke, D.L.; Tompa, K.

1983-01-01

The temperature dependence of the laboratory frame spin-lattice relaxation time of 27 Al nuclei is measured in 5N Al and in dilute Al-Ti, Al-Cr, Al-Mn, and Al-Cu alloys at 5.7 and 9.7 MHz resonance frequencies. The relaxation in pure aluminium is found to be purely due to the conduction electrons. An excess T 1 -relaxation contribution is detected in all Al-3d alloys investigated above 670 K. The excess relaxation rate is proportional to the impurity content and the temperature dependence of the excess contribution is of Arrhenius-type with an activation energy of (1.3 +- 0.3) eV for all of the investigated alloys. The relaxation contribution is found to be quadrupolar in origin and is caused by the relative diffusional jumps of solute atoms and Al atoms relatively far from the impurity. (author)

Predicting the Extent of Inundation due to Sea-Level Rise: Al Hamra Development, Ras Al Khaimah, UAE. A Pilot Project

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Arthur Robert M.

2016-06-01

Full Text Available As new information is received, predictions of sea-level rise resulting from global warming continue to be revised upwards. Measurements indicate that the rise in sea-level is continuing at, or close to, the worst case forecasts (Kellet et al. 2014. Coastal areas are coming under increasing risk of inundation and flooding as storms are predicted to increase in frequency and severity, adding to the risk of inundation due to higher sea levels. Stakeholders, government agencies, developers and land owners require accurate, up to date information to be able to protect coastal areas. Geographic Information Systems (GIS along with accurate remote sensing technologies such as LiDAR provides the best means for delivering this information. Using these technologies, this paper predicts the risk posed to a large multi-use development in the emirate of Ras Al Khaimah, UAE. This development, Al Hamra Village, is situated on the coast of the Arabian Gulf. Al Hamra’s physical relationship to the Gulf is in common with other developments in Ras Al Khaimah in its and for this reason has been used as a pilot project. The resulting GIS model shows that Al Hamra is indeed at risk from predicted flood events. How this information can be used as a planning tool for numerous strategies is discussed in this paper.

The Effect of Si Morphology on Machinability of Al-Si Alloys

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Muhammet Uludağ

2015-12-01

Full Text Available Many of the cast parts require some sort of machining like milling, drilling to be used as a finished product. In order to improve the wear properties of Al alloys, Si is added. The solubility of Si in Al is quite low and it has a crystallite type structure. It behaves as particulate metal matrix composite which makes it an attractive element. Thus, the wear and machinability properties of these type of alloys depend on the morphology of Si in the matrix. In this work, Sr was added to alter the morphology of Si in Al-7Si and Al-12Si. Cylindrical shaped samples were cast and machinability characteristics of Sr addition was studied. The relationship between microstructure and machinability was evaluated.

Interfacial phenomena in the reactions of Al-B, Al-Ti-B, and Al-Zr-B alloys with KF-AlF3 and NaF-AlF3 melts

International Nuclear Information System (INIS)

Lee, M.S.; Terry, B.S.; Grieveson, P.

1993-01-01

The interfacial phenomena occurring during the contacting of liquid Al-B, Al-Ti-B, and Al-Zr-B melts with KF-AlF 3 liquid fluxes have been investigated by optical examination of quenched metal drops previously immersed in the liquid fluxes. Reactions in the Al-B/KF-AlF 3 system involve the formation of metastable AlB 12 at the metal/flux interface. At high KBF 4 levels in the flux, the AlB 12 is dispersed in the flux and also at low KBF 4 levels in the metal. Reactions in the Al-Ti-B/KF-AlF 3 system involve the formation of TiB 2 , which may be dispersed in either the metal or the flux depending upon the composition of the flux. The results obtained for the Al-Ti-B/NaF-AlF 3 and Al-Zr-B/KF-AlF 3 systems were similar to those observed for the Al-Ti-B/KF-AlF 3 system

Thermal shock behavior of nano-sized SiC particulate reinforced AlON composites

Energy Technology Data Exchange (ETDEWEB)

Zhao, X.J. [Department of Materials Science and Engineering, School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Ru, H.Q., E-mail: ruhq@smm.neu.edu.cn [Department of Materials Science and Engineering, School of Materials and Metallurgy, Northeastern University, Shenyang, Liaoning 110004 (China); Chen, D.L., E-mail: dchen@ryerson.ca [Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Ontario M5B 2K3 (Canada); Zhang, N.; Liang, B. [Key Laboratory of Advanced Materials Manufacturing Technology of Liaoning Province, Shenyang University, Shenyang, Liaoning 110044 (China)

2012-03-25

Highlights: Black-Right-Pointing-Pointer Addition of nano-SiC particles enhances residual strength and critical temperature. Black-Right-Pointing-Pointer Young's modulus decreases with increasing quenching temperature. Black-Right-Pointing-Pointer Linear relationship between residual strength and thermal shock times is obtained. Black-Right-Pointing-Pointer Rougher fracture surfaces in the SiC-AlON composites are observed. - Abstract: Aluminum oxynitride (AlON) has been considered as a potential ceramic material for high-performance structural and advanced refractory applications. Thermal shock resistance is a major concern and an important performance index of high-temperature ceramics. While silicon carbide (SiC) particles have been proven to improve mechanical properties of AlON ceramic, the high-temperature thermal shock behavior was unknown. The aim of this investigation was to identify the thermal shock resistance and underlying mechanisms of AlON ceramic and 8 wt% SiC-AlON composites over a temperature range between 175 Degree-Sign C and 275 Degree-Sign C. The residual strength and Young's modulus after thermal shock decreased with increasing quenching temperature and thermal shock times due to large temperature gradients and thermal stresses caused by abrupt water-quenching. A linear relationship between the residual strength and thermal shock times was observed in both pure AlON and SiC-AlON composites. The addition of nano-sized SiC particles increased both residual strength and critical temperature from 200 Degree-Sign C in the monolithic AlON to 225 Degree-Sign C in the SiC-AlON composites due to the toughening effect, the lower coefficient of thermal expansion and higher thermal conductivity of SiC. The enhancement of the thermal shock resistance in the SiC-AlON composites was directly related to the change of fracture mode from intergranular cracking along with cleavage-type fracture in the AlON to a rougher fracture surface with ridge

Correlative characterization of primary Al{sub 3}(Sc,Zr) phase in an Al–Zn–Mg based alloy

Energy Technology Data Exchange (ETDEWEB)

Li, J.H., E-mail: jie-hua.li@hotmail.com [Institute of Casting Research, Montanuniversität Leoben, A-8700 Leoben (Austria); Wiessner, M. [Materials Center Leoben Forschung GmbH, A-8700 Leoben (Austria); Albu, M. [Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Center for Electron Microscopy (Austria); Wurster, S. [Department of Materials Physics, Montanuniversität Leoben, Erich Schmid Institute of Materials Science of the Austrian Academy of Sciences, A-8700 Leoben (Austria); Sartory, B. [Materials Center Leoben Forschung GmbH, A-8700 Leoben (Austria); Hofer, F. [Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Center for Electron Microscopy (Austria); Schumacher, P. [Institute of Casting Research, Montanuniversität Leoben, A-8700 Leoben (Austria); Austrian Foundry Research Institute, A-8700 Leoben (Austria)

2015-04-15

Three-dimensional electron backscatter diffraction, focused ion beam, transmission electron microscopy and energy filtered transmission electron microscopy were employed to investigate the structural information of primary Al{sub 3}(Sc,Zr) phase, i.e. size, shape, element distribution and orientation relationship with the α-Al matrix. It was found that (i) most primary Al{sub 3}(Sc,Zr) phases have a cubic three-dimensional morphology, with a size of about 6–10 μm, (ii) most primary Al{sub 3}(Sc,Zr) phases are located within the α-Al matrix, and exhibit a cube to cube orientation relationship with the α-Al matrix, and (iii) a layer by layer growth was observed within primary Al{sub 3}(Sc,Zr) phases. Al, Cu, Si and Fe are enriched in the α-Al matrix between the layers of cellular eutectic Al{sub 3}(Sc,Zr) phase, while Sc, Ti and Zr are enriched in small Al{sub 3}(Sc,Zr) phases. A peritectic reaction and subsequent eutectic reaction between Al{sub 3}Sc and Al was proposed to interpret the observed layer by layer growth. This paper demonstrates that the presence of impurities (Fe, Si, Cu, Ti) in the diffusion field surrounding the growing Al{sub 3}(Sc,Zr) particle enhances the heterogeneous nucleation of Al{sub 3}(Sc,Zr) phases. - Highlights: • Most fine cubic primary Al{sub 3}(Sc,Zr) phases were observed within the α-Al matrix. • A layer by layer growth within primary Al{sub 3}(Sc,Zr) phase was observed. • A peritectic and subsequent eutectic reaction between Al{sub 3}Sc and Al was proposed. • Impurities in diffusion fields enhance heterogeneous nucleation of Al{sub 3}(Sc,Zr)

Al-Anon family groups' newcomers and members: Concerns about the drinkers in their lives.

Science.gov (United States)

Timko, Christine; Cronkite, Ruth; Laudet, Alexandre; Kaskutas, Lee Ann; Roth, Jeffrey; Moos, Rudolf H

2014-01-01

Despite Al-Anon's widespread availability and use, knowledge is lacking about the drinkers in attendees' lives. We filled this gap by describing and comparing Al-Anon newcomers' and members' reports about their "main drinker" (main person prompting initial attendance). Al-Anon's World Service Office mailed a random sample of groups, yielding completed surveys from newcomers (N = 362) and stable members (N = 265). Newcomers' and members' drinkers generally were comparable. They had known their drinker for an average of 22 years and been concerned about his or her's drinking for 9 years; about 50% had daily contact with the drinker. Most reported negative relationship aspects (drinker gets on your nerves; you disagree about important things). Newcomers had more concern about the drinker's alcohol use than members did, and were more likely to report their drinkers' driving under the influence. Drinkers' most frequent problem due to drinking was family arguments, and most common source of help was 12-step groups, with lower rates among drinkers of newcomers. Concerns spurring initial Al-Anon attendance were the drinker's poor quality of life, relationships, and psychological status; goals for initial attendance reflected these concerns. The drinker's alcohol use was of less concern in prompting initial Al-Anon attendance, and, accordingly, the drinker's reduced drinking was a less frequently endorsed goal of attendance. Family treatments for substance use problems might expand interventions and outcome domains beyond abstinence and relationship satisfaction to include the drinker's quality of life and psychological symptoms and in turn relieve concerns of family members. © American Academy of Addiction Psychiatry.

Synthesizing (ZrAl3 + AlN)/Mg-Al composites by a 'matrix exchange' method

Science.gov (United States)

Gao, Tong; Li, Zengqiang; Hu, Kaiqi; Han, Mengxia; Liu, Xiangfa

2018-06-01

A method named 'matrix exchange' to synthesize ZrAl3 and AlN reinforced Mg-Al composite was developed in this paper. By inserting Al-10ZrN master alloy into Mg matrix and reheating the cooled ingot to 550 °C, Al and Mg atoms diffuse to the opposite side. As a result, liquid melt occurs once the interface areas reach to proper compositions. Then dissolved Al atoms react with ZrN, leading to the in-situ formation of ZrAl3 and AlN particles, while the Al matrix is finally replaced by Mg. This study provides a new insight for preparing Mg composites.

Rare-earth transition-metal intermetallics: Structure-bonding-property relationships

Energy Technology Data Exchange (ETDEWEB)

Han, M. K. [Iowa State Univ., Ames, IA (United States)

2006-01-01

The explorations of rare-earth, transition metal intermetallics have resulted in the synthesis and characterization, and electronic structure investigation, as well as understanding the structure-bonding property relationships. The work has presented the following results: (1) Understanding the relationship between compositions and properties in LaFe_13-xSi_x system: A detailed structural and theoretical investigation provided the understanding of the role of a third element on stabilizing the structure and controlling the transformation of cubic NaZn{sub 13}-type structures to the tetragonal derivative, as well as the relationship between the structures and properties. (2) Synthesis of new ternary rare-earth iron silicides Re_2-xFe₄Si_14-y and proposed superstructure: This compound offers complex structural challenges such as fractional occupancies and their ordering in superstructure. (3) Electronic structure calculation of FeSi₂: This shows that the metal-semiconductor phase transition depends on the structure. The mechanism of band gap opening is described in terms of bonding and structural distortion. This result shows that the electronic structure calculations are an essential tool for understanding the relationship between structure and chemical bonding in these compounds. (4) Synthesis of new ternary rare-earth Zinc aluminides Tb₃Zn_3.6Al_7.4: Partially ordered structure of Tb₃Zn_3.6Al_7.4 compound provides new insights into the formation, composition and structure of rare-earth transition-metal intermetallics. Electronic structure calculations attribute the observed composition to optimizing metal-metal bonding in the electronegative (Zn, Al) framework, while the specific ordering is strongly influenced by specific orbital interactions. (5) Synthesis of new structure type of Zn₃₉(Cr_xAl_1-x)₈₁

Rare-Earth Transition-Metal Intermetallics: Structure-bonding-Property Relationships

Energy Technology Data Exchange (ETDEWEB)

Han, Mi-Kyung [Iowa State Univ., Ames, IA (United States)

2006-01-01

Our explorations of rare-earth, transition metal intermetallics have resulted in the synthesis and characterization, and electronic structure investigation, as well as understanding the structure-bonding-property relationships. Our work has presented the following results: (1) Understanding the relationship between compositions and properties in LaFe_13-xSi_x system: A detailed structural and theoretical investigation provided the understanding of the role of a third element on stabilizing the structure and controlling the transformation of cubic NaZn₁₃-type structures to the tetragonal derivative, as well as the relationship between the structures and properties. (2) Synthesis of new ternary rare-earth iron silicides RE_2-xFe₄Si_14-y and proposed superstructure: This compound offers complex structural challenges such as fractional occupancies and their ordering in superstructure. (3) Electronic structure calculation of FeSi₂: This shows that the metal-semiconductor phase transition depends on the structure. The mechanism of band gap opening is described in terms of bonding and structural distortion. This result shows that the electronic structure calculations are an essential tool for understanding the relationship between structure and chemical bonding in these compounds. (4) Synthesis of new ternary rare-earth Zinc aluminides Tb₃Zn_3.6Al_7.4: Partially ordered structure of Tb_3.6Zn_13-xAl_7.4 compound provides new insights into the formation, composition and structure of rare-earth transition-metal intermetallics. Electronic structure calculations attribute the observed composition to optimizing metal-metal bonding in the electronegative (Zn, Al) framework, while the specific ordering is strongly influenced by specific orbital interactions. (5) Synthesis of new structure type of Zn₃₉(Cr_xAl_1-x

Coupled growth of Al-Al2Cu eutectics in Al-Cu-Ag alloys

International Nuclear Information System (INIS)

Hecht, U; Witusiewicz, V; Drevermann, A

2012-01-01

Coupled eutectic growth of Al and Al 2 Cu was investigated in univariant Al-Cu-Ag alloys during solidification with planar and cellular morphology. Experiments reveal the dynamic selection of small spacings, below the minimum undercooling spacing and show that distinct morphological features pertain to nearly isotropic or anisotropic Al-Al 2 Cu interfaces.

AL ITTIJAHAT AL MUNHARIFAH FI AT TAFSIR LI BADLI ASHAB AL MADZAHIB AL NAHWIYYAH WA BADL MAN YAJHALUNA QAWAID AL LUGHAH AL ARABIYYAH FI NADHAR MUHAMMAD HUSAIN AL DZAHABIY

Directory of Open Access Journals (Sweden)

Misbakhudin Misbakhudin

2017-06-01

Full Text Available One of the most precious achievement in qur’anic studies was the book of Al-Ittijâhât al-Munharifah fî al-Tafsîr: Dawâfi’uha wa Daf’uha written by A great Islamic scholar, Muhammad Husein al-Dzahabî. He was succeeded in discussing several issues of corruptions of the exegesis of the holy Qur’an. This article is aimed to explain and to describe his analysis toward several corrupted linguist interpretations in their originations and such corrupted linguistic interpretations of the holy Qur’an which are ignoring Arabic structures and grammers

Modeling of mechanical properties of as-cast Mg-Li-Al alloys based on PSO-BP algorithm

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Li Ming

2012-05-01

Full Text Available Artificial neural networks have been widely used to predict the mechanical properties of alloys in material research. This study aims to investigate the implicit relationship between the compositions and mechanical properties of as-cast Mg-Li-Al alloys. Based on the experimental collection of the tensile strength and the elongation of representative Mg-Li-Al alloys, a momentum back-propagation (BP neural network with a single hidden layer was established. Particle swarm optimization (PSO was applied to optimize the BP model. In the neural network, the input variables were the contents of Mg, Li and Al, and the output variables were the tensile strength and the elongation. The results show that the proposed PSO-BP model can describe the quantitative relationship between the Mg-Li-Al alloy’s composition and its mechanical properties. It is possible that the mechanical properties to be predicted without experiment by inputting the alloy composition into the trained network model. The prediction of the influence of Al addition on the mechanical properties of as-cast Mg-Li-Al alloys is consistent with the related research results.

Calculation of Al2O3 contents in Al2O3-PTFE composite thick films fabricated by using the aerosol deposition

International Nuclear Information System (INIS)

Kim, Hyung-Jun; Kim, Yoon-Hyun; Nam, Song-Min; Yoon, Young-Joon; Kim, Jong-Hee

2010-01-01

Low-temperature fabrication of Al 2 O 3 -PTFE (poly tetra fluoro ethylene) composite thick films for flexible integrated substrates was attempted by using the aerosol deposition method. For optimization of composite thick films, a novel calculation method for the ceramic contents in the composites was attempted. Generally, a thermogravimetry (TG) analysis is used to calculate the ceramic contents in the ceramic-polymer composites. However, the TG analysis requires a long measurement time in each analysis, so we studied a novel calculation method that used a simple dielectric measurement. We used Hashin-Shtrikman bounds to obtain numerical results for the relationship between the dielectric constant of the composites and the contents of Al 2 O 3 . A 3-D electrostatic simulation model similar to the deposited Al 2 O 3 -PTFE composite thick films was prepared, and the simulation result was around the lower bound of the Hashin-Shtrikman bounds. As a result, we could calculate the Al 2 O 3 contents in the composites with a low error of below 5 vol.% from convenient dielectric measurements, and the Al 2 O 3 contents ranged from 51 vol.% to 54 vol.%.

Characterizing lake water quality, cyanotoxins, and Amyotrophic Lateral Sclerosis (ALS).

Science.gov (United States)

Torbick, N.; Ziniti, B.; Stommel, E.; Linder, E.; Andrew, A.; Bradley, W.; Shi, X.

2016-12-01

Concern over toxins and public health threats resulting from Cyanobacterial Harmful Algal Blooms (CHABs) have gained attention as reoccurring and seasonal blooms persist in many waters. Concordantly, climate change has been suggested to increase the intensity, duration, and frequency of CHAB events. Humans may be exposed to the cyanotoxins produced by cyanobacteria via the food chain, drinking water, recreational use of waterbodies and by aerosolization. Exposure to the cyanobacterial neurotoxin, β-N-methylamino-L-alanine (BMAA) that has been found in the brains of ALS patients is a hypothesized mechanism. The goals of this research initiative are to investigate spatiotemporal relationships between inland lake water quality and ALS across northern New England (NNE). Multiscale satellite remote sensing was integrated with in situ lake and toxin sampling to provide robust spatiotemporal exposure risk metrics characterizing CHAB. Semi-analytical, shape, and empirical algorithms were bldned together tp generate spatiotemporal measures of chl-a and PC with R2 ranging from 0.65-0.92 using withheld samples. Postmortem aerosolization analysis found 85% of high risk patients to express phycobillin in lung tissue using fluroesence microscopy. To scal eup to the region we employed complementing spatial statistics and a Bayesian hierarchical framework to model relationships between lake risk metrics and ALS case location across NNE. The eco-epidemiolgical modeling results show that on average poorer water quality conditions and higher measures of cyanobacteria are associated with increased odds of belonging to a normalized ALS hot spots and risk of ALS. This has broad societal impacts as the frequency, duration, and magnitude of cyanobacterial harmful algal blooms are expanding and this work helps characterize lake ecosystem services and human health.

Structure, thermal and mechanical properties of in situ Al-based metal matrix composite reinforced with Al2O3 and TiC submicron particles

International Nuclear Information System (INIS)

Yu Peng; Mei Zhi; Tjong, S.C.

2005-01-01

We report herein the structure and characterization of in situ Al-based metal matrix composites (MMCs) prepared from the Al-10 wt.% TiO 2 and Al-10 wt.% TiO 2 -1.5 wt.% C systems via hot isostatic pressing (HIP) at 1000 deg C and 100 MPa. The structure, morphology and thermal behavior of HIPed samples were studied by means of the X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results indicated that fined Al 2 O 3 particles and large intermetallic Al 3 Ti plates were in situ formed in the Al-10 wt.% TiO 2 sample during HIPing. However, the introduction of C to the Al-TiO 2 system was beneficial to eliminate large intermetallic Al 3 Ti plates. In this case, Al 2 O 3 and TiC submicron particles were in situ formed in the Al-10 wt.% TiO 2 -1.5 wt.% C sample. Three-point-bending test showed that the strength and the strain-at-break of the HIPed Al-10 wt.% TiO 2 -1.5 wt.% C sample were significantly higher than those of its Al-10 wt.% TiO 2 counterpart. The improvement was derived from the elimination of bulk Al 3 Ti intermetallic plates and from the formation of TiC submicron particles. DSC measurements and thermodynamic analyses were carried out to reveal the reaction formation mechanisms of in situ reinforcing phases. The DSC results generally correlated well with the theoretical predictions. Finally, the correlation between the structure-property relationships of in situ composites is discussed

INTERAKSI EDUKATIF MENURUT PEMIKIRAN AL-GHAZALI

Directory of Open Access Journals (Sweden)

Harizal Anhar

2013-08-01

Full Text Available Education is an interaction activity between teachers and students in a classroom learning. Harmonious interaction between teachers and students greatly affect the success of learning. But in reality, the issue of today's educational interaction is less attention of the education stakeholder. The evidence is that some educators develop bad relationship with the students as being arrogant and violent means in resolving problems in the classroom. These conditions depreciate the relation between the teacher and the students in or outside the class that it is not surprising some students attack the teachers. In fact, the problem of educational interaction is not a new problem in educational world. Al-Ghazali is an Islamic education leaders who concentrated on the issue since the 5th century H. This article aims at examining a depth theory of al-Ghazali on educational interaction in a number of work related to education. This research is library research through ccontent analysis to find its relevance to the world of Islamic education at the moment. The results show that Al-Ghazali has a major contribution in developing the concept of educational interaction in Islamic education. The concept of Al-Ghazali can be reference in overcoming the problems of educational interaction nowadays through an approach which is in line with the the latest developments.

Al-Si-Re Alloys Cast by the Rapid Solidification Process / Stopy Al-Si-Re Odlewane Metodą Rapid Solidification

Directory of Open Access Journals (Sweden)

Szymanek M.

2015-12-01

Full Text Available The aim of the studies described in this article was to present the effect of rare earth elements on aluminium alloys produced by an unconventional casting technique. The article gives characteristics of the thin strip of Al-Si-RE alloy produced by Rapid Solidification (RS. The effect of rare earth elements on structure refinement, i.e. on the size of near-eutectic crystallites in an aluminium-silicon alloy, was discussed. To determine the size of crystallites, the Scherrer X-ray diffraction method was used. The results presented capture relationships showing the effect of variable casting parameters and chemical composition on microstructure of the examined alloys. Rapid Solidification applied to Al-Si alloys with the addition of mischmetal (Ce, La, Ne, Pr refines their structure.

Analyses of TmAl{sub 2} and ErAl{sub 2} composite for use as an active magnetic regenerator close to liquid helium temperature

Energy Technology Data Exchange (ETDEWEB)

Souza, M.V. de, E-mail: marcos_vinicios@hotmail.com [Núcleo de Pós-Graduação em Física, Campus prof. José Aluísio de Campos, UFS, 49100-000, São Cristóvão, SE (Brazil); Silva, J.A. da [Núcleo de Pós-Graduação em Física, Campus prof. José Aluísio de Campos, UFS, 49100-000, São Cristóvão, SE (Brazil); Silva, L.S. [Núcleo de Pós-Graduação em Física, Campus prof. José Aluísio de Campos, UFS, 49100-000, São Cristóvão, SE (Brazil); Instituto Federal de Tocantins, IFTO – Campus Colinas do Tocantins, AV. Bernardo Sayao S/N, Chácara Raio de Sol, Setor Santa Maria, CEP 77760-000, Colinas do Tocantins, TO (Brazil)

2017-07-01

Highlights: • Modeling of the thermodynamics quantities in RAl{sub 2} (R = Er, Tm) single crystal and polycrystal. • An optimal hybrid magnetocaloric material using TmAl{sub 2} and ErAl{sub 2} compounds. • Suppression of the ferromagnetic canted order in the compound TmAl{sub 2} in single crystal form. - Abstract: We report the thermodynamic properties of selected intermetallic RAl{sub 2} (R = Er, Tm) compounds calculated by using a model Hamiltonian, including the Zeeman-exchange interactions and the crystalline electrical field, which are responsible for the magnetic anisotropy. The relationship between the behavior of the temperature-dependent magnetization, calculated in different crystallographic directions for several magnetic fields, and the influence of spin reorientation on the magnetocaloric effect, is discussed. In order to validate the obtained theoretical results, experimental data are compared to calculated data. Also, an optimum molar fraction of the ErAl{sub 2} and TmAl{sub 2} composite was determined theoretically, showing a high potential for use in a regenerative thermal cycle, especially close to the liquid helium temperature range.

Examining the language and behavioural profile in FTD and ALS-FTD.

Science.gov (United States)

Saxon, Jennifer A; Thompson, Jennifer C; Jones, Matthew; Harris, Jennifer M; Richardson, Anna Mt; Langheinrich, Tobias; Neary, David; Mann, David Ma; Snowden, Julie S

2017-08-01

A proportion of patients with behavioural variant frontotemporal dementia (bvFTD) develop amyotrophic lateral sclerosis (ALS). It is currently unknown whether the behavioural and cognitive syndrome in bvFTD with ALS (ALS-FTD) is indistinguishable from that of bvFTD alone. A retrospective cohort of 241 patients with clinical diagnoses of bvFTD (n=185) or ALS-FTD (n=56) was examined with respect to behavioural, cognitive and neuropsychiatric symptoms. Features were rated as present or absent based on information recorded from clinical interviews and detailed neuropsychological assessment. A number of behavioural and affective changes were reported more frequently in bvFTD than ALS-FTD: social disinhibition (pALS-FTD than bvFTD (pALS-FTD than bvFTD: agrammatism (pALS-FTD. In particular, while changes in social behaviour are prominent in bvFTD alone, there may be a comparatively greater degree of language impairment in ALS-FTD. Prospective exploration of the pattern of differences between these groups will be essential. Identification of a distinct neuropsychological phenotype in ALS-FTD may have clinical implications for early diagnosis, disease management and care planning and theoretical implications for our understanding of the relationship between ALS and FTD. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Interaction and actors‘ identities in business relationships

OpenAIRE

La Rocca, Antonella; Snehota, Ivan

2011-01-01

The existence of continuous buyer-seller relationships in business-to- business markets has been evidenced in numerous empirical studies and more recently acknowledged in marketing in general. Research shows that the critical process in the development of business relationships is interaction (Håkansson et al., 2009). This study deals with the interactive behaviours of actors and focuses on how actors interpret each other’s identities. We review three fields of research that offer impul...

Relationships among the Microstructure, Mechanical Properties, and Fatigue Behavior in Thin Ti6Al4V

Directory of Open Access Journals (Sweden)

Y. Fan

2016-01-01

Full Text Available The microstructures of Ti6Al4V are complex and strongly affect its mechanical properties and fatigue behavior. This paper investigates the role of microstructure on mechanical and fatigue properties of thin-section Ti6Al4V sheets, with the aim of reviewing the effects of microstructure on fatigue properties where suboptimal microstructures might result following heat treatment of assemblies that may not be suited to further annealing, for example, following laser welding. Samples of Ti6Al4V sheet were subjected to a range of heat treatments, including annealing and water quenching from temperatures ranging from 650°C to 1050°C. Micrographs of these samples were inspected for microstructure, and hardness, 0.2% proof stress, elongation, and fracture strength were measured and attributed back to microstructure. Fractography was used to support the findings from microstructure and mechanical analyses. The strength ranking from high to low for the microstructures of thin Ti6Al4V sheets observed in this study is as follows: acicular α′ martensite, Widmanstätten, bimodal, and equiaxed microstructure. The fatigue strength ranking from high to low is as follows: equiaxed, bimodal, Widmanstätten, and acicular α′ martensite microstructure.

Lead exposure among children from native communities of the Peruvian Amazon basin Exposición al plomo en niños de comunidades indígenas de la cuenca del Amazonas en el Perú

Directory of Open Access Journals (Sweden)

Cynthia Anticona

2012-04-01

Full Text Available OBJECTIVE: To assess potential risk factors associated with elevated blood lead levels (BLLs among children in two communities from the Corrientes River basin in the Peruvian Amazon. METHODS: Children aged 0-17 years were screened for BLLs, hemoglobin levels, and anthropometric measures. Dwelling, family, and child data were collected through a parental questionnaire. Statistical analysis included descriptive and bivariate analysis. Multiple linear and logistic regressions using generalized estimating equations were also conducted to determine associated risk factors. A map of each community was drawn to examine the spatial distribution of BLLs. RESULTS: Of 208 children (88 from 23 households of the Peruanito community and 120 from 28 households of Santa Isabel, 27.4% had BLLs > 10 µg/dL. The geometric mean (± standard deviation BLL was 8.7 ± 4.0 µg/dL (range 3.0-26.8 µg/dL. In the total population, linear regression analysis indicated that age was positively associated with BLLs (P 10 µg/dL than girls (P 10 µg/dL had 45.0% higher odds of presenting BLLs > 10 µg/dL than children whose mothers had BLLs 10 µg/dL were the main risk factors for elevated BLLs. The higher risk in boys 7-17 years suggests that exposure could be related to specific activities in this group, such as fishing and hunting. Continuous monitoring of BLLs in the Corrientes River population is recommended.OBJETIVO: Evaluar los potenciales factores de riesgo asociados con niveles elevados de plomo en sangre (Pbs en niños de dos comunidades de la cuenca del río Corrientes en la Amazonia peruana. MÉTODOS: Se estudiaron de manera sistemática los niveles de PbS, la concentración de hemoglobina y las medidas antropométricas en niños de 0 a 17 años. A través de un cuestionario efectuado a los padres se recopilaron datos sobre la vivienda, la familia y los niños. El análisis estadístico incluyó el análisis descriptivo y de dos variables. También se llevaron a

Relationship between bias voltage and microstructure as well as properties of CrAlYN films

International Nuclear Information System (INIS)

Fu Ying-Ying; Li Hong-Xuan; Ji Li; Liu Xiao-Hong; Zhou Hui-Di; Chen Jian-Min; Liu Liu

2015-01-01

In this work, a series of CrAlYN films doped with 1 at.% yttrium were deposited by unbalanced reactive magnetron sputtering under different bias voltages. The effects of bias voltage on microstructure and properties of the CrAlYN films were subsequently investigated. It is found that all the as-deposited films have similar chemical composition and crystalline structure. However, the bias voltage has significant impact on the mechanical properties and oxidation resistance of the resulting films. Namely, the film deposited at 100 V has the highest hardness and best oxidation resistance, which are mainly attributed to its denser structure and higher Al content than others. In addition, the film obtained at 100 V exhibits superior oxidation resistance even at 1000 °C, and good friction and wear properties at 600 and 800 °C, and the latter two are mainly ascribed to the formation of compact transfer layer on the worn surfaces. However, this film experienced obvious wear loss at low testing temperatures (i.e., 200 and 400 °C) due to the serious abrasive wear. (paper)

Perils of correlating CUSUM-transformed variables to infer ecological relationships (Breton et al. 2006; Glibert 2010)

Science.gov (United States)

Cloern, James E.; Jassby, Alan D.; Carstensen, Jacob; Bennett, William A.; Kimmerer, Wim; Mac Nally, Ralph; Schoellhamer, David H.; Winder, Monika

2012-01-01

We comment on a nonstandard statistical treatment of time-series data first published by Breton et al. (2006) in Limnology and Oceanography and, more recently, used by Glibert (2010) in Reviews in Fisheries Science. In both papers, the authors make strong inferences about the underlying causes of population variability based on correlations between cumulative sum (CUSUM) transformations of organism abundances and environmental variables. Breton et al. (2006) reported correlations between CUSUM-transformed values of diatom biomass in Belgian coastal waters and the North Atlantic Oscillation, and between meteorological and hydrological variables. Each correlation of CUSUM-transformed variables was judged to be statistically significant. On the basis of these correlations, Breton et al. (2006) developed "the first evidence of synergy between climate and human-induced river-based nitrate inputs with respect to their effects on the magnitude of spring Phaeocystis colony blooms and their dominance over diatoms."

Phylogenetic relationship among Kenyan sorghum germplasms ...

African Journals Online (AJOL)

Mr Kiboi

phylogenetic relationships based on 10 DNA fragments at AltSB loci with SbMATE, ORF9 and MITE primers. .... estimate the overall genetic diversity in Kenyan sorghum lines: Cheprot et al. 3529 ..... EARN project and Generation Challenge (GCP), ... genetics and molecular biology of plant aluminum resistance and toxicity.

Influence of Al addition on phase transformation and thermal stability of nickel silicides on Si(0 0 1)

International Nuclear Information System (INIS)

Huang, Shih-Hsien; Twan, Sheng-Chen; Cheng, Shao-Liang; Lee, Tu; Hu, Jung-Chih; Chen, Lien-Tai; Lee, Sheng-Wei

2014-01-01

Highlights: ► The presence of Al slows down the Ni 2 Si–NiSi phase transformation but significantly promotes the NiSi 2−x Al x formation. ► The behavior of phase transformation strongly depends on the Al concentration of the initial Ni 1−x Al x alloys. ► The Ni 0.91 Al 0.09 /Si system exhibits remarkably improved thermal stability, even after high temperature annealing for 1000 s. ► The relationship between microstructures, electrical property, and thermal stability of Ni(Al) silicides is discussed. -- Abstract: The influence of Al addition on the phase transformation and thermal stability of Ni silicides on (0 0 1)Si has been systematically investigated. The presence of Al atoms is found to slow down the Ni 2 Si–NiSi phase transformation but significantly promote the NiSi 2−x Al x formation during annealing. The behavior of phase transformation strongly depends on the Al concentration of the initial Ni 1−x Al x alloys. Compared to the Ni 0.95 Pt 0.05 /Si and Ni 0.95 Al 0.05 /Si system, the Ni 0.91 Al 0.09 /Si sample exhibits remarkably enhanced thermal stability, even after high temperature annealing for 1000 s. The relationship between microstructures, electrical property, and thermal stability of Ni silicides is discussed to elucidate the role of Al during the Ni 1−x Al x alloy silicidation. This work demonstrated that thermally stable Ni 1−x Al x alloy silicides would be a promising candidate as source/drain (S/D) contacts in advanced complementary metal–oxide-semiconductor (CMOS) devices

Mechanical and microstructural characterization of dispersion strengthened Al-C system nanocomposites

International Nuclear Information System (INIS)

Santos-Beltran, A.; Gallegos-Orozco, V.; Reyes, R. Goytia; Miki-Yoshida, M.; Estrada-Guel, I.; Martinez-Sanchez, R.

2010-01-01

Al and different amounts of C and C-Cu mixtures were used to produce Al-C and Al-C-Cu powder samples by mechanical milling. Microhardness tests were carried out to evaluate the mechanical properties of the nanocomposites in the as-milled condition. In general, the measured values were considerably higher than pure Al. In order to determine the causes of this hardening, the crystallite size and dislocation density were measured by means of X-ray analyses coupled with a convolutional multiple whole profile (CMWP) fitting program and a comparison with atomic force microscopy (AFM) observations. In Al-C samples, the hardening is mainly due to the decrease of the crystallite size, however for the Al-C-Cu, an additional strengthening mechanism appears and it seems that it is due by a dispersion of graphite nanoparticles in the Al matrix. The strengthening contributions of dislocation density, crystallite size and particle dispersion were modeled by superposing of every single contribution to strengthening (via hardness analyses). We found a direct relationship between the mechanical properties and the nominal amount of C-Cu, where Cu apparently acts as C nanoparticles integration and dispersion agent.

The Coach-Athlete Relationship Questionnaire (CART-Q): development and initial validation.

Science.gov (United States)

Jowett, Sophia; Ntoumanis, Nikos

2004-08-01

The purpose of the present study was to develop and validate a self-report instrument that measures the nature of the coach-athlete relationship. Jowett et al.'s (Jowett & Meek, 2000; Jowett, in press) qualitative case studies and relevant literature were used to generate items for an instrument that measures affective, cognitive, and behavioral aspects of the coach-athlete relationship. Two studies were carried out in an attempt to assess content, predictive, and construct validity, as well as internal consistency, of the Coach-Athlete Relationship Questionnaire (CART-Q), using two independent British samples. Principal component analysis and confirmatory factor analysis were used to reduce the number of items, identify principal components, and confirm the latent structure of the CART-Q. Results supported the multidimensional nature of the coach-athlete relationship. The latent structure of the CART-Q was underlined by the latent variables of coaches' and athletes' Closeness (emotions), Commitment (cognitions), and Complementarity (behaviors).

Familial ALS

Science.gov (United States)

Boylan, Kevin

2015-01-01

Synopsis Genes linked to ALS susceptibility are being identified at an increasing rate owing to advances in molecular genetic technology. Genetic mechanisms in ALS pathogenesis appear to exert major effects in ~10% of patients, but genetic factors at some level may be important components of disease risk in most ALS patients. Identification of gene variants associated with ALS has informed concepts of the pathogenesis of ALS, aided the identification of therapeutic targets, facilitated research to develop new ALS biomarkers, and supported the establishment of clinical diagnostic tests for ALS-linked genes. Translation of this knowledge to ALS therapy development is ongoing. PMID:26515623

Malamih al-Ashwat al-'Arabiyyah wa Makharijaha

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Amrah Muhammad Kasim

2015-12-01

Full Text Available This writing discusses on al-ashwat al-‘arabiyyah that is known with “phonetic” term. It talks and interprets makharij al-huruf or place for producing sounds and also processing production of sounds by parts of mouth in Arabic language. The problems of sounds and its systems in Arabic language have been conducted by the scholars of al-ashwat al-‘arabiyyah attractively, neatly, and detail and gotten ahead the phonetic western scholars. Part of their analysis results formulate the study about al-ashwat al-sakinah (al-Shamit is known with vocal and consonant sounds in research questions shawait – shawamit. Ibnu Jinni has formulated “harakat”(wowel in Arabic language and dimension of letter  mad and liyn on alif  letter - waw - ya’ (ا و ي, from these letters create  harakat fathah, dammah, and kasrah. Moreover, in this writing also exist the description of hija’i letters and its makhraj that are correct from parts of mouth and the unity of coordinative sounds that produce sounds in morphemes arrangement, in one word that produces meaning. The result of phonological study has divided al-ashwat to be kinds of sound like the pronounced sounds, produced sounds from mouth, and heard sound.

A Framework for Assessing and Managing Large Purchaser - Minority Supplier Relationships in Supplier Diversity Initiatives

OpenAIRE

Theodorakopoulos, Nicholas; Ram, Monder

2008-01-01

Supplier diversity initiatives can function as platforms for EMSs strategic learning (Theodorakopoulos et al., 2005; Theodorakopoulos & Ram, 2006) and the scant research in supplier diversity underscores the importance of relationship factors to the success of supplier diversity/development programmes (e.g. Pearson et al., 1993). However, purchaser-supplier relationship management as a vehicle for enhancing EMSs learning and supply capabilities has not been examined to any length within the c...

Al-Anon newcomers: benefits of continuing attendance for six months.

Science.gov (United States)

Timko, Christine; Laudet, Alexandre; Moos, Rudolf H

2016-07-01

Al-Anon Family Groups, a 12-step mutual-help program for people concerned about another person's drinking, is the most widely used form of help by Concerned Others. This longitudinal study examined newcomers' outcomes of attending Al-Anon. Aims were to better understand early gains from Al-Anon to inform efforts in the professional community to facilitate concerned others' attendance of and engagement in Al-Anon. We compared two groups of Al-Anon newcomers who completed surveys at baseline and 6 months later: those who discontinued attendance by the 6-month follow-up (N = 133), and those who were still attending Al-Anon meetings (N = 97); baseline characteristics were controlled in these comparisons. Newcomers who sustained participation in Al-Anon over the first 6 months of attendance were more likely than those who discontinued participation during the same period to report gains in a variety of domains, such as learning how to handle problems due to the drinker, and increased well-being and functioning, including reduced verbal or physical abuse victimization. Newcomers to Al-Anon reported more personal gains than drinker-related gains. The most frequent drinker gain was a better relationship with the Concerned Other; attendees were more likely to report this, as well as daily, in-person contact with the drinker. Al-Anon participation may facilitate ongoing interaction between Concerned Others and drinkers, and help Concerned Others function and feel better. Thus, short-term participation may be beneficial. Health-care professionals should consider providing referrals to Al-Anon and monitoring early attendance.

The ALS Gun Electronics system

International Nuclear Information System (INIS)

Lo, C.C.

1993-05-01

The ALS Gun Electronics system has been designed to accommodate gun with a custom made socket and high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters

The ALS gun electronics system

International Nuclear Information System (INIS)

Lo, C.C.

1993-01-01

The ALS Gun Electronics system has been designed to accommodate the gun with a custom made socket and a high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters

Mechanical, dynamical and thermodynamic properties of Al-3wt%Mg from first principles

Energy Technology Data Exchange (ETDEWEB)

Yang, Rong [Chongqing Jiaotong Univ., Chongqing (China). College of Materials Science and Engineering; Tang, Bin [Chongqing City Management College, Chongqing (China). Inst. of Finance and Trade; Gao, Tao [Sichuan Univ., Chengdu (China). Inst. of Atomic and Molecular Physics

2017-09-01

The mechanical, dynamical and thermodynamic properties of Al-3wt%Mg have been investigated using the first-principles method. The calculated structural parameter is in good agreement with previous works. Results for the elastic modulus, stress-strain relationships, ideal tensile and shear strengths are presented. Al-3wt%Mg is found to have larger moduli and higher strengths than Al, which is consistent with its exploitation in Al precipitate-hardening mechanisms. The partial density of states (PDOS) show that the partly covalent-like bonding through Al p-Mg s hybridization is the origin of excellent mechanical properties of Al-3wt%Mg. The phonon dispersion curves indicate that Al-3wt%Mg is dynamically stable at ambient pressure and 0 K. Furthermore, the Helmholtz free energy ΔF, the entropy S, the constant-volume specific heat C{sub V} and the phonon contribution to the internal energy ΔE are predicted using the phonon density of states. We expect that our work can provide useful guidance to help with the performance of Al-3wt%Mg.

Mechanical, dynamical and thermodynamic properties of Al-3wt%Mg from first principles

International Nuclear Information System (INIS)

Yang, Rong; Tang, Bin; Gao, Tao

2017-01-01

The mechanical, dynamical and thermodynamic properties of Al-3wt%Mg have been investigated using the first-principles method. The calculated structural parameter is in good agreement with previous works. Results for the elastic modulus, stress-strain relationships, ideal tensile and shear strengths are presented. Al-3wt%Mg is found to have larger moduli and higher strengths than Al, which is consistent with its exploitation in Al precipitate-hardening mechanisms. The partial density of states (PDOS) show that the partly covalent-like bonding through Al p-Mg s hybridization is the origin of excellent mechanical properties of Al-3wt%Mg. The phonon dispersion curves indicate that Al-3wt%Mg is dynamically stable at ambient pressure and 0 K. Furthermore, the Helmholtz free energy ΔF, the entropy S, the constant-volume specific heat C_V and the phonon contribution to the internal energy ΔE are predicted using the phonon density of states. We expect that our work can provide useful guidance to help with the performance of Al-3wt%Mg.

Transient oxidation of Al-deposited Fe-Cr-Al alloy foil

International Nuclear Information System (INIS)

Andoh, A.

1997-01-01

The oxide phases formed on an Al-deposited Fe-Cr-Al alloy foil and an Fe-Cr-Al alloy foil of the same levels of Al and (La+Ce) contents, and their oxidation kinetics have been studied in air at 1173 and 1373 K using TGA, XRD and SEM. Al deposition promotes the growth of metastable aluminas (θ-Al 2 O 3 , γ-Al 2 O 3 ). Scales consisting of θ-Al 2 O 3 and a small amount of α-Al 2 O 3 develop on the Al-deposited foil at 1173 K and exhibit the whisker-type morphology. In the early stage of oxidation at 1373 K, thick scales consisting of θ-Al 2 O 3 and α-Al 2 O 3 grow rapidly on the Al-deposited foil. The transformation from θ-Al 2 O 3 to α-Al 2 O 3 is very fast, and the scales result in only α-Al 2 O 3 . In contrast, α-Al 2 O 3 scales containing a minor amount of FeAl 2 O 4 develop on the alloy foil. The growth rate of α-Al 2 O 3 scales on the Al-deposited foil is smaller than that on the alloy foil and very close to that on NiAl at 1373 K. (orig.)

Structural characteristics of single crystalline GaN films grown on (111) diamond with AlN buffer

DEFF Research Database (Denmark)

Pécz, Béla; Tóth, Lajos; Barna, Árpád

2013-01-01

Hexagonal GaN films with the [0001] direction parallel to the surface normal were grown on (111) oriented single crystalline diamond substrates by plasma-assisted molecular beam epitaxy. Pre-treatments of the diamond surface with the nitrogen plasma beam, prior the nucleation of a thin AlN layer......, eliminated the inversion domains and reduced the density of threading dislocations in the GaN epilayers. The films have an in-plane epitaxial relationship [1010]GaN//[110]diamond. Thus GaN (0001) thin films of single epitaxial relationship and of single polarity were realised on diamond with AlN buffer....

PREDICTING NORMATIVE AND PROBLEMATIC FAMILY PATHWAYS TO THE TRANSITION TO SIBLINGHOOD: COMMENTARY ON VOLLING ET AL.'S MONOGRAPH.

Science.gov (United States)

Howe, Nina

2017-09-01

Volling et al.'s monograph provides a rich, thoughtful, and rigorous account of how the transition to siblinghood is experienced by the first-born child and the family. In their comprehensive longitudinal study, they followed 241 families from the prenatal period before the second-born's birth until this child was 12-months old. Siblings are a critical, but understudied, relationship in children's development; the challenges posed in researching sibling dynamics in the context of the family are discussed. Prior psychodynamic and developmental research literature is critiqued, which places the current study into perspective and indicates the important theoretical frameworks (i.e., developmental psychopathology and developmental ecological systems) employed by Volling et al. to advance our understanding of this critical transition in the life of the family. The longitudinal study design, sample characteristics, identification of possible trajectories of adjustment (or not) to the birth of the sibling, and selection of family and child variables are addressed. The sophisticated statistical methods (Growth Mixture Modeling and data mining procedures) employed to predict child adjustment in association with parenting variables over time and sibling relationship quality at 12 months identified low- and high-risk trajectories on the seven subscales of the Child Behavior Check List (CBCL). This afforded a nuanced investigation of a variety of potentially problematic child behaviors (e.g., aggression, withdrawal, negative emotionality, somatic problems) in association with parenting behaviors. A final discussion included study limitations, significant strengths, and implications for clinicians and other professionals. The study's conclusion is that most children and families are resilient, take the birth of a sibling in their stride, and do not exhibit empirical evidence of a developmental crisis, as argued by earlier psychodynamic authors. © 2017 The Society for Research

Composition-Structure-Property Relationships in Boroaluminosilicate Glasses

DEFF Research Database (Denmark)

Zheng, Qiuju; Potuzak, M.; Mauro, J.C.

2012-01-01

boroaluminosilicate glasses from peralkaline to peraluminous compositions by substituting Al2O3 for SiO2. Our results reveal a pronounced change in all the measured physical properties (density, elastic moduli, hardness, glass transition temperature, and liquid fragility) around [Al2O3]–[Na2O]=0. The structural......The complicated structural speciation in boroaluminosilicate glasses leads to a mixed network former effect yielding nonlinear variation in many macroscopic properties as a function of chemical composition. Here we study the composition–structure–property relationships in a series of sodium...

First-principles molecular dynamics investigation of thermal and mechanical stability of the TiN(001)/AlN and ZrN(001)/AlN heterostructures

International Nuclear Information System (INIS)

Ivashchenko, V.I.; Veprek, S.; Turchi, P.E.A.; Shevchenko, V.I.; Leszczynski, J.; Gorb, L.; Hill, F.

2014-01-01

First-principles quantum molecular dynamics investigations of TiN(001)/AlN and ZrN(001)/AlN heterostructures with one and two monolayers (1 ML and 2 ML) of AlN interfacial layers were carried out in the temperature range of 0–1400 K with subsequent static relaxation. It is shown that the epitaxially stabilized cubic B1-AlN interfacial layers are preserved in all TiN(001)/AlN heterostructures over the whole temperature range. In the ZrN(001)/AlN heterostructures, the B1-AlN(001) interfacial layer exists at 0 K, but it transforms into a distorted one at 10 K consisting of tetrahedral AlN 4 , octahedral AlN 6 , and AlN 5 units. The thermal stability of the interfaces was investigated by studying the phonon dynamic stability of the B1-AlN phase with different lattice parameters. The calculations showed that the B1-AlN interface should be unstable in ZrN(001)/AlN heterostructures and nanocomposites, and in those based on transition metal nitrides with lattice parameters larger than 4.4 Å. Electronic band structure calculations showed that energy gap forms around the Fermi energy for all interfaces. The formation of the interfacial AlN layer in TiN and ZrN crystals reduces their ideal tensile and shear strengths. Upon tensile load, decohesion occurs between Ti (Zr) and N atoms adjacent to the 1 ML AlN interfacial layer, whereas in the case of 2 ML AlN it occurs inside the TiN and ZrN slabs. The experimentally reported strength enhancement in the TiN/AlN and ZrN/AlN heterostructures is attributed to impeding effect of the interfacial layer on the plastic flow. - Highlights: • First-principles quantum molecular dynamics studies were conducted. • TiN- and ZrN-based heterostructures with one and two AlN interfacial layers. • Stability and structural transformation between 0 and 1400 K have been calculated. • Stress–strain relationships and ideal strengths determined. • Systems which may form stable superhard heterostructures are identified

First-principles molecular dynamics investigation of thermal and mechanical stability of the TiN(001)/AlN and ZrN(001)/AlN heterostructures

Energy Technology Data Exchange (ETDEWEB)

Ivashchenko, V.I., E-mail: ivash@ipms.kiev.ua [Institute of Problems of Material Science, National Academy of Science of Ukraine, Krzhyzhanosky str. 3, 03142 Kyiv (Ukraine); Veprek, S., E-mail: stan.veprek@lrz.tum.de [Department of Chemistry, Technical University Munich, Lichtenbergstrasse 4, D-85747 Garching (Germany); Turchi, P.E.A. [Lawrence Livermore National Laboratory (L-352), P.O. Box 808, Livermore, CA 94551 (United States); Shevchenko, V.I. [Institute of Problems of Material Science, National Academy of Science of Ukraine, Krzhyzhanosky str. 3, 03142 Kyiv (Ukraine); Leszczynski, J. [Department of Chemistry and Biochemistry, Interdisciplinary Center for Nanotoxicity, Jackson State University, Jackson, MS 39217 (United States); Gorb, L. [Department of Chemistry and Biochemistry, Interdisciplinary Center for Nanotoxicity, Jackson State University, Jackson, MS 39217 (United States); U.S. Army ERDC, Vicksburg, MS 39180 (United States); Hill, F. [U.S. Army ERDC, Vicksburg, MS 39180 (United States)

2014-08-01

First-principles quantum molecular dynamics investigations of TiN(001)/AlN and ZrN(001)/AlN heterostructures with one and two monolayers (1 ML and 2 ML) of AlN interfacial layers were carried out in the temperature range of 0–1400 K with subsequent static relaxation. It is shown that the epitaxially stabilized cubic B1-AlN interfacial layers are preserved in all TiN(001)/AlN heterostructures over the whole temperature range. In the ZrN(001)/AlN heterostructures, the B1-AlN(001) interfacial layer exists at 0 K, but it transforms into a distorted one at 10 K consisting of tetrahedral AlN{sub 4}, octahedral AlN{sub 6}, and AlN{sub 5} units. The thermal stability of the interfaces was investigated by studying the phonon dynamic stability of the B1-AlN phase with different lattice parameters. The calculations showed that the B1-AlN interface should be unstable in ZrN(001)/AlN heterostructures and nanocomposites, and in those based on transition metal nitrides with lattice parameters larger than 4.4 Å. Electronic band structure calculations showed that energy gap forms around the Fermi energy for all interfaces. The formation of the interfacial AlN layer in TiN and ZrN crystals reduces their ideal tensile and shear strengths. Upon tensile load, decohesion occurs between Ti (Zr) and N atoms adjacent to the 1 ML AlN interfacial layer, whereas in the case of 2 ML AlN it occurs inside the TiN and ZrN slabs. The experimentally reported strength enhancement in the TiN/AlN and ZrN/AlN heterostructures is attributed to impeding effect of the interfacial layer on the plastic flow. - Highlights: • First-principles quantum molecular dynamics studies were conducted. • TiN- and ZrN-based heterostructures with one and two AlN interfacial layers. • Stability and structural transformation between 0 and 1400 K have been calculated. • Stress–strain relationships and ideal strengths determined. • Systems which may form stable superhard heterostructures are identified.

Ideal shear strength and deformation behaviours of L10 TiAl from ...

Indian Academy of Sciences (India)

Guangxi Teachers Education University, Nanning 530023, China. MS received 18 October 2014; accepted 11 April 2016. Abstract. The stress–strain relationships for four different shear processes of L10 TiAl have been .... aThis work; bRef.

Mechanical properties and oxidation behaviour of (Al,Cr)N and (Al,Cr,Si)N coatings for cutting tools deposited by HPPMS

Energy Technology Data Exchange (ETDEWEB)

Bobzin, K.; Bagcivan, N.; Immich, P. [Surface Engineering Institute, RWTH Aachen University, Augustinerbach 4-22, D-52056 Aachen (Germany); Bolz, S. [Surface Engineering Institute, RWTH Aachen University, Augustinerbach 4-22, D-52056 Aachen (Germany)], E-mail: info1@iot.rwth-aachen.de; Cremer, R.; Leyendecker, T. [CemeCon AG, Wuerselen (Germany)

2008-12-01

Hard coatings with high hardness, high oxidation resistance and thermal stability are used for economical machining. In this regard nanostructured (Cr,Al)N and nc-(Cr,Al)N/a-Si{sub 3}N{sub 4} films were sputtered on tungsten carbide tools and WC/Co samples by using the HPPMS (High Power Pulse Magnetron Sputtering) technology. The relationship between coating composition, microstructure and mechanical properties was investigated by using X-ray diffraction, Scanning Electron Microscopy (SEM), and Nanoindentation. The maximum hardness value was about 40 GPa. For the coatings the Al-content was varied from 10-90 at.% while the silicon content was about 5 at.% for the (Cr,Al,Si)N. As this study focuses on oxidation behaviour of the deposited coatings, annealing tests were carried out in air at 1000 deg. C . HPPMS is a promising technology to ensure a uniform coating distribution, especially for complex shaped substrates like cutting tools or moulds. SEM pictures of the cross section have been taken around the cutting edge to determine the deposition rate and the film growth. The coatings morphology has been compared to m. f. (middle frequency)- and d. c. (direct current)-sputtered nanocomposite (Cr,Al,Si)N films indicating enhanced properties due to the application of the HPPMS-technology with regard to denser structure, higher hardness, favourable surface topography and better thickness uniformity.

Proton irradiation studies on Al and Al5083 alloy

Science.gov (United States)

Bhattacharyya, P.; Gayathri, N.; Bhattacharya, M.; Gupta, A. Dutta; Sarkar, Apu; Dhar, S.; Mitra, M. K.; Mukherjee, P.

2017-10-01

The change in the microstructural parameters and microhardness values in 6.5 MeV proton irradiated pure Al and Al5083 alloy samples have been evaluated using different model based techniques of X-ray diffraction Line Profile Analysis (XRD) and microindendation techniques. The detailed line profile analysis of the XRD data showed that the domain size increases and saturates with irradiation dose both in the case of Al and Al5083 alloy. The corresponding microstrain values did not show any change with irradiation dose in the case of the pure Al but showed an increase at higher irradiation doses in the case of Al5083 alloy. The microindendation results showed that unirradiated Al5083 alloy has higher hardness value compared to that of unirradiated pure Al. The hardness increased marginally with irradiation dose in the case of Al5083, whereas for pure Al, there was no significant change with dose.

Enhanced heterogeneous nucleation on oxides in Al alloys by intensive shearing

International Nuclear Information System (INIS)

Li, H T; Wang, Y; Fan, Z

2012-01-01

Oxides, in liquid aluminium alloys, can cause severe difficulties during casting, contribute to the formation of cast defects and degrade the mechanical properties of cast components. In this paper, microstructural characteristics of naturally occurring oxides in the melts of commercial purity aluminium and Al-Mg binary alloys have been investigated. They are characterised by densely populated oxide particles within liquid oxide films. With intensive shearing, the particle agglomerates are dispersed into uniformly distributed individual particles. It was found that with intensive melt shearing, grain refinement of α-Al can be achieved by the dispersed oxide particles. The smaller lattice misfit between the oxide particles and the α-Al phase is characterised by a well defined crystallographic orientation relationship. And the mechanisms of grain refinement are discussed.

KONSELING PERKAWINAN DALAM PERSPEKTIF AL-QUR’AN

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Abdul Basit

2017-02-01

source in the development of counseling because in the Qur'an, there are a lot of discussion about people and their relationships with God, among others, and with the universe. The views of the Al-Qur’an on human being comprehensivelyand it can be an alternative to cover the weaknesses in some of the existing counseling approach. Marriage counseling in the Qur'an includes the process of education, advocacy, development, and problem solving of marital. Furthermore, marriage counseling in the Qur'an also does not separate between family counseling, individual counseling and marriage counseling itself. Everything becomes a unity in marriage counseling, begins from premarital education, the process of marriage, after marriage, the family formation, to the process of divorce (if it happens. The approach of the Qur'an in performing marriage counseling is comprehensive and multi-functional, i.e, a combination of approaches premarital counseling, structured modalities, multifamily group counseling, and marital therapy. Key words: counseling, marriage, Al-Qur’an, family, and Islam

PEMBARUAN MASLAḤAH DALAM MAQĀṢID AL- SHARĪ‘AH: TELAAH HUMANISTIS TENTANG AL-KULLIYYĀT AL-KHAMSAH

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Zaenuddin Mansyur

2012-06-01

Full Text Available Abstract:   In order to answer a variety of issues faced by human being in the current era, such as human rights abuses, social disintegration, and terrorism, the renewal of Islamic law in the level of theoretical and practical aspects is very urgent. This paper aims to examine one of the Islamic legal reform efforts, namely to build a more technical understanding of the concept of maṣlaḥah contained in the maqāṣīd sharī‘ah, called the al-kulliyat al-khamsah. Therefore, the concept of maṣlaḥah in ḥifẓ al-dīn is technically defined as al-ḥurriyah al-i‘tiqād (freedom of religion and schools; in ḥifẓ al-nafs as al-karamat al-insān (human being breeding; in ḥifẓ al-nasl as ḥifẓ al-usrah (wholeness and harmony of the family; in ḥifẓ al-māl as al-taḍammun al-insān (social solidarity , and in ḥifẓ al-‘aql as al-ḥuqūq as al-tarbiyāt (increasing human resources quality.Abstrak: Demi menjawab aneka persoalan zaman yang dihadapi manusia era sekarang, seperti penyelewengan terhadap HAM, disintegrasi sosial, dan terorisme, maka pembaharuan hukum Islam dalam tataran teoretis dan praktis urgen dilakukan. Tulisan ini bertujuan untuk mengkaji salah satu upaya pembaruan hukum Islam, yaitu membangun pemahaman yang lebih teknis terhadap konsep maṣlaḥah yang terkandung dalam maqāṣīd sharī‘ah, yang disebut dengan al-kulliyāt al-khamsah. Oleh karena itu, konsep maṣlaḥah dalam ḥifẓu al-dīn secara teknis dimaknai sebagai ḥurriyah al-i‘tiqād (kebebasan untuk beragama dan beraliran; dalam ḥifẓu al-nafs sebagai al-karāmāt al-insān (pemuliaan kemanusiaan; dalam ḥifẓu al-nasl sebagai ḥifẓu al-usrah (keutuhan dan keharmonisan keluarga; dalam ḥifẓu al-māl sebagai al-taḍammun al-insān (solidaritas sosial; dan dalam ḥifẓu al-‘aql sebagai al-ḥuqūq al-tarbiyāt (peningkatan sumber daya manusia.

Intoxicación plúmbica crónica y alteraciones del crecimiento y desarrollo cognitivo-emocional en niños

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Julián Vega

2003-06-01

Full Text Available Objetivo: Determinar la asociación entre intoxicación plúmbica crónica y alteraciones del crecimiento y desarrollo cognitivo-emocional en niños del colegio "María Reiche"- Callao. Diseño: Estudio observacional de corte transversal. Material y Métodos: A 70 niños de 8 a 12 años de edad del C.E. Nº 5045 "María Reiche" del A.A.H.H. "Puerto Nuevo"- Callao, que participaron en el estudio de dosaje de plomo en sangre hecho por la Dirección General de Salud Ambiental en 1999, se les aplicó pruebas de seguimiento de instrucciones, habilidades motoras, comunicativas, manipulativas, académicas y la lista de chequeo de ansiedad. Se midió el coeficiente intelectual e índice de masa corporal. Para el procesamiento de los datos se empleó las pruebas chi-cuadrado, t de Student, correlación y regresión lineal simple, usando el paquete estadístico SPSS versión 11.0, con un nivel de confianza de 95%. Resultados: Los niveles de plomo en sangre y los grados de ansiedad se relacionaron significativamente mediante la prueba chi-cuadrado (p=0,025; se encontró diferencias significativas entre las medias del puntaje de la lista de chequeo de ansiedad y la categorización de los niveles de plomo, mediante la prueba t de Student (p= 0,031. La relación entre los niveles de plomo en sangre y el coeficiente intelectual, las habilidades académicas, motoras, comunicativas, manipulativas, seguimiento de instrucciones e índice de masa corporal no resultaron significativos. Conclusiones: Se encontró asociación significativa entre la intoxicación plúmbica crónica y el grado de ansiedad (desarrollo emocional. Sin embargo, no se encontró asociación con el crecimiento ni con el desarrollo cognitivo.

Combustion synthesis of AlB2-Al2O3 composite powders with AlB2 nanowire structures

Science.gov (United States)

Yang, Pan; Xiao, Guoqing; Ding, Donghai; Ren, Yun; Yang, Shoulei; Lv, Lihua; Hou, Xing

2018-05-01

Using of Al and B2O3 powders as starting materials, and Mg-Al alloy as additives, AlB2-Al2O3 composite powders with AlB2 nanowire structures were successfully fabricated via combustion synthesis method in Ar atmosphere at a pressure of 1.5 MPa. The effect of different amount of Mg-Al alloy on the phase compositions and morphology of the combustion products was investigated. The results revealed that AlB2 and Al2O3 increased, whereas Al decreased with the content of Mg-Al alloy increasing. The impurities MgAl2O4 and AlB12 would exist in the sample with adding of 18 wt% Mg-Al alloy. Interestingly, FESEM/TEM/EDS results showed that AlB2 nanowires were observed in the products when the content of Mg-Al alloy is 6 wt% and 12 wt%. The more AlB2 nanowires can be found as the content of Mg-Al alloy increased. And the yield of AlB2 nanowires with the diameter of about 200 nanometers (nm) and the length up to several tens of micrometers (μm) in the combustion product is highest when the content of Mg-Al alloy is 12 wt%. The vapor, such as Mg-Al (g), B2O2 (g), AlO (g) and Al2O (g), produced during the process of combustion synthesis, reacted with each other to yield AlB2 nanowires by vapor-solid (VS) mechanism and the corresponding model was also proposed.

The effects of boron in TiAl/Ti3Al

International Nuclear Information System (INIS)

Feng, C.R.; Michel, D.J.; Crowe, C.R.

1989-01-01

The authors discuss the TiAl/Ti 3 Al interfacial misfit dislocations structures investigated by TEM in Ti-45Al alloy and Ti-45Al/TiB 2 composite. For TiAl with c/a = 1.02, only a single set of misfit dislocation arrays are crystallographically possible; these were observed in Ti-45Al alloy. However, the observation of three sets of misfit dislocation arrays in the Ti-45Al/TiB 2 composite suggests that the occupation of octahedral sites in the TiAl structure by excess boron was responsible for a decrease in the c/a ratio leading to an increased fcc character of the TiAl at the TiAl/Ti 3 Al interface

Determination of the load state of lead-acid batteries using neural networks; Determinacion del estado de carga de baterias plomo-acido utilizando redes neuronales

Energy Technology Data Exchange (ETDEWEB)

Cristin V, Miguel A; Ortega S, Cesar A [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2005-07-01

The charge of lead-acid batteries (LAB), as in any other type of batteries, consists of replacing the energy consumed during the discharge. Nevertheless, as no physical or chemical process is good enough to totality recharge a battery, it is necessary to supply to it more than the 100% of the energy demanded during its discharge. A critical factor to make a suitable load control of the batteries is to determine its own state of load. That is to say, to have an efficient load control, it is necessary to count on means that allow to accurately determining the residual capacity of the battery to deliver load. This one is the one of the aspects of greater interest in the research centers around world. For this reason, in this work it was pretended to develop a calculation algorithm of the state of load of batteries based on a fuzzy-neural network that could calculate the state of load without using the battery current as an input. This is because one of the main problems for the designers of battery load controllers is the correct supervision of the current that circulates around the system in all the rank of operation of the same one because the sensors do not have a linear behavior. [Spanish] La recarga de baterias plomo-acido (BPA), como cualquier otro tipo de baterias, consiste en reponer la energia consumida durante la descarga. Sin embargo, como ningun proceso fisico o quimico es lo bastante eficiente para recargar a totalidad una bateria, es necesario suministrarle mas del 100% de la energia demandada durante su descarga. Un factor critico para realizar un adecuado control de carga de las baterias, es determinar su propio estado de carga. Es decir, para tener un control de carga eficiente, es necesario contar con un medio que permita determinar con precision la capacidad remanente de la bateria para entregar carga. Este es uno de los aspectos de mayor interes en los centros de investigacion alrededor el mundo. Por tal razon, en este trabajo se propuso

Nocturnal hypoxia in ALS is related to cognitive dysfunction and can occur as clusters of desaturations.

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Su-Yeon Park

Full Text Available Amyotrophic lateral sclerosis (ALS is a neurodegenerative disease that leads to progressive weakness of the respiratory and limb muscles. Consequently, most patients with ALS exhibit progressive hypoventilation, which worsens during sleep. The aim of this study was to evaluate the relationship between nocturnal hypoxia and cognitive dysfunction and to assess the pattern of nocturnal hypoxia in patients with ALS.Twenty-five patients with definite or probable ALS underwent neuropsychologic testing, nocturnal pulse oximetry, and capnography. Patients were grouped according to the presence of nocturnal hypoxia (SpO2<95% for ≥10% of the night and their clinical characteristics and cognitive function were compared.Compared to patients without nocturnal hypoxia, those with nocturnal hypoxia (n = 10, 40% had poor memory retention (p = 0.039 and retrieval efficiency (p = 0.045. A cluster-of-desaturation pattern was identified in 7 patients (70% in the Hypoxia Group.These results suggest that nocturnal hypoxia can be related to cognitive dysfunction in ALS. In addition, a considerable number of patients with ALS may be exposed to repeated episodes of deoxygenation-reoxygenation (a cluster-of-desaturation pattern during sleep, which could be associated with the generation of reactive oxygen species. Further studies are required to define the exact causal relationships between these phenomena, the exact manifestations of nocturnal cluster-of-desaturation patterns, and the effect of clusters of desaturation on ALS progression.

In Situ Fabrication of AlN Coating by Reactive Plasma Spraying of Al/AlN Powder

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Mohammed Shahien

2011-10-01

Full Text Available Reactive plasma spraying is a promising technology for the in situ formation of aluminum nitride (AlN coatings. Recently, it became possible to fabricate cubic-AlN-(c-AlN based coatings through reactive plasma spraying of Al powder in an ambient atmosphere. However, it was difficult to fabricate a coating with high AlN content and suitable thickness due to the coalescence of the Al particles. In this study, the influence of using AlN additive (h-AlN to increase the AlN content of the coating and improve the reaction process was investigated. The simple mixing of Al and AlN powders was not suitable for fabricating AlN coatings through reactive plasma spraying. However, it was possible to prepare a homogenously mixed, agglomerated and dispersed Al/AlN mixture (which enabled in-flight interaction between the powder and the surrounding plasma by wet-mixing in a planetary mill. Increasing the AlN content in the mixture prevented coalescence and increased the nitride content gradually. Using 30 to 40 wt% AlN was sufficient to fabricate a thick (more than 200 µm AlN coating with high hardness (approximately 1000 Hv. The AlN additive prevented the coalescence of Al metal and enhanced post-deposition nitriding through N₂ plasma irradiation by allowing the nitriding species in the plasma to impinge on a larger Al surface area. Using AlN as a feedstock additive was found to be a suitable method for fabricating AlN coatings by reactive plasma spraying. Moreover, the fabricated coatings consist of hexagonal (h-AlN, c-AlN (rock-salt and zinc-blend phases and certain oxides: aluminum oxynitride (Al₅O₆N, cubic sphalerite Al₂₃O₂₇N₅ (ALON and Al₂O₃. The zinc-blend c-AlN and ALON phases were attributed to the transformation of the h-AlN feedstock during the reactive plasma spraying. Thus, the zinc-blend c-Al

Aprovechamiento de semillas de Dipteryx odorata (Aublet. Willd. (Shihuahuaco como producto alimenticio

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Aparicio Limache Alonzo

2015-12-01

Full Text Available Considerando la necesidad de contribuir a la diversificación de insumos alimenticios mediante el aprovechamiento masivo de las partes no maderables de las especies forestales tropicales con énfasis en la región Ucayali - Perú, se exploró la posibilidad de utilizar a las semillas o almendras del Dipteryx odorata como producto alimenticio de consumo humano. Para ello, se sometió a un análisis nutricional, determinación de contenido de minerales y se complementó con una investigación bibliográfica para identificar los antecedentes de uso y exigencias que implica su conversión en un bionegocio. Así, se determinaron la materia seca, extracto etéreo, fibra cruda y proteína cruda en 88,89 %, 19 %, 16,75 % y 1,51 % respectivamente. Al cuantificar los oligoelementos como el zinc, hierro, cobre, sodio, plomo, magnesio se encontraron valores de 39,29; 25,86; 12,36; 4,79; 3,04; 1,31 ppm respectivamente. La investigación bibliográfica, demostró que en áreas rurales dichas almendras son utilizadas en la dieta alimenticia de la población. En Europa, son consideradas gourmet básico para la coctelería e ideal para repostería exótica. Se concluye indicando que por su contenido nutricional y de minerales las almendras de shihuahuaco en cantidades pequeñas, son aptas para consumo humano. Como limitante para su aprovechamiento en bionegocio, es el contenido de plomo que requiere desarrollo de estudios previos para neutralizar su efecto nocivo que genera problemas gastrointestinales por exceso de consumo.

Instability of TiC and TiAl3 compounds in Al-10Mg and Al-5Cu alloys by addition of Al-Ti-C master alloy

Institute of Scientific and Technical Information of China (English)

无

2006-01-01

The performance of Al-Ti-C master alloy in refining Al-10Mg and A1-5Cu alloys was studied by using electron probe micro-analyzer (EPMA) and X-ray diffractometer (XRD) analysis.The results indicate that there are obvious fading phenomena in both Al-10Mg and Al-5Cu alloys with the addition of Al-5Ti-0.4C refiner which contains TiC and TiAl3 compounds.Mg element has no influence on the stability of TiC and TiAl3, while TiC particles in Al-10Mg alloy react with Al to form Al4C3 particles, resulting in the refinement fading.However, TiC particles are relatively stable in Al-5Cu alloy, while TiAl3 phase reacts with Al2Cu to produce a new phase Ti(Al, Cu)2, which is responsible for the refinement fading in Al-5Cu alloy.These indicate that the refinement fading will not occur only when both the TiC particles and TiAl3 compound of Al-Ti-C refiner are stable in Al alloys.

PEMAHAMAN HADITS TARBAWI BURHAN AL ISLAM AL ZARNUJI DALAM KITAB TA’LIM AL MUTA’ALLIM

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Benny Afwadzi

2017-01-01

Full Text Available This paper explores the understanding of tarbawi (education hadith from one of the major influential clerics in the Islamic educational system, especially in pesantren. He is Burhan al Islam al Zarnuji with his landmark book Ta’lim al Muta’allim. The conclusion that can be drawn is that al Zarnuji has shades of sufistical view in understanding tarbawi hadith. This can be seen in his understanding of hadith on obligation to seek knowledge (thalab al ilmi faridhatun ‘ala kulli muslimin wa muslimatin, which is interpreted as ilm al hal, the science concerning the condition of the human religious or simplistically said as the religious sciences; and the hadith of intention of studying (innama al a’malu bi al niyyat with the intention for the sake of the hereafter and religion, not mundane. Such an understanding is not something taken for granted, but it can be reinterpreted and perfected in accordance with the spirit of the times of context.

Microstructural evaluation of interfacial intermetallic compounds in Cu wire bonding with Al and Au pads

International Nuclear Information System (INIS)

Kim, Hyung Giun; Kim, Sang Min; Lee, Jae Young; Choi, Mi Ri; Choe, Si Hyun; Kim, Ki Hong; Ryu, Jae Sung; Kim, Sangshik; Han, Seung Zeon; Kim, Won Yong; Lim, Sung Hwan

2014-01-01

A comparative study on the difference in interfacial behavior of thermally aged Cu wire bonding with Al and Au pads was conducted using transmission electron microscopy. During high-temperature lifetime testing of Cu wire bonding with Al and Au pads at 175 °C for up to 2000 h, different growth rates and growth characteristics were investigated in the Cu–Al intermetallic compounds (IMCs), including CuAl 2 , CuAl and Cu 9 Al 4 , and in the Cu–Au IMCs, including (Au,Cu), Cu 3 Au and (Cu,Au). Because of the lower growth rates and greater ductility of Cu–Au IMCs compared to those of Cu–Al IMCs, the Cu wire bonding with the Au pad showed relatively better thermal aging properties of bond pull strength and ball shear strength than those with the Al pad counterpart. In this study, the coherent interfaces were found to retard the growth of IMCs, and a variety of orientation relationships between wire, pad and interfacial IMCs were identified

Calculation of Gibbs energy of Zr-Al-Ni, Zr-Al-Cu, Al-Ni-Cu and Zr-Al-Ni-Cu liquid alloys based on quasiregular solution model

International Nuclear Information System (INIS)

Li, H.Q.; Yang, Y.S.; Tong, W.H.; Wang, Z.Y.

2007-01-01

With the effects of electronic structure and atomic size being introduced, the mixing enthalpy as well as the Gibbs energy of the ternary Zr-Al-Cu, Ni-Al-Cu, Zr-Ni-Al and quaternary Zr-Al-Ni-Cu systems are calculated based on quasiregular solution model. The computed results agree well with the experimental data. The sequence of Gibbs energies of different systems is: G Zr-Al-Ni-Cu Zr-Al-Ni Zr-Al-Cu Cu-Al-Ni . To Zr-Al-Cu, Ni-Al-Cu and Zr-Ni-Al, the lowest Gibbs energy locates in the composition range of X Zr 0.39-0.61, X Al = 0.38-0.61; X Ni = 0.39-0.61, X Al = 0.38-0.60 and X Zr = 0.32-0.67, X Al = 0.32-0.66, respectively. And to the Zr-Ni-Al-Cu system with 66.67% Zr, the lowest Gibbs energy is obtained in the region of X Al = 0.63-0.80, X Ni = 0.14-0.24

Experimental determination of the constitution and the phase relationships in Zr (2.5-8.0)at.%Nb (0-6.7)at.%Al alloys with 750at.ppm0 and 250at.ppmN, between 730-900 deg C

International Nuclear Information System (INIS)

Peruzzi Bardella, A.; Bolcich, J.C.

1990-01-01

Zr alloys with 2.5 to 8.0 at%Nb and 0 to 6.7 at%Al, were subjected to dynamic and static treatments between 730-900 deg C and studied by qualitative and quantitative optical metallography, electrical resistance, X-ray diffractometry and electron microanalysis. The experimental data were analyzed by taking into account the effects of oxygen and nitrogen impurities. The main results for Zr-Nb-Al alloys with 750 at.ppm0 and 250 at.ppmN are the following: a) Equilibrium relationships are established between α (hcp), β (bcc) and Zr 3 Al (Cu 3 Au) phases along isothermal sections at 730, 771 and 800 deg C. b) β/α+β boundaries are determined along iso-aluminium vertical sections at 6.7, 3.3 and 0 at%Al. As for the first two iso-aluminium sections, the β/α+β equilibrium boundary corresponding to the binary Zr-Nb system is found to have a positive curvature, which is contrary to what has been reported in the literature. The increase in the Al content shifts the T β/α+β at a rate of 5.1 to 8.5 deg C/at.%Al, depending on Nb content. c) The addition of Al to Zr-Nb alloys increases the partial solubility of Nb in the α phase, its maximum value at 730 deg C being about 0.7-0.8 at% for 4 at%Al. d) Solubility values for Al in α-phase of Zr-Al were estimated by extrapolation from ternary alloys. These estimates help to solve an existing discrepancy on the Zr-Al system. (Author)

Bipolar characteristics of AlGaN/AlN/GaN/AlGaN double heterojunction structure with AlGaN as buffer layer

International Nuclear Information System (INIS)

Peng, Enchao; Wang, Xiaoliang; Xiao, Hongling; Wang, Cuimei; Yin, Haibo; Chen, Hong; Feng, Chun; Jiang, Lijuan; Hou, Xun; Wang, Zhanguo

2013-01-01

Highlights: •2DEG and 2DHG coexist in the AlGaN/AlN/GaN/AlGaN DH-structure. •The sheet densities of 2DEG and 2DHG vary with buffer Al content and GaN thickness. •The conditions for the disappearance of 2DHG are discussed. •Increasing buffer Al content provides better electron confinement. •Dislocation scattering is reduced in the DH-structure. -- Abstract: This is a theoretical study of AlGaN/AlN/GaN/AlGaN double heterojunction (DH) structure with AlGaN as buffer layer. Our calculation shows that as the buffer Al content increases, though two-dimensional electron gas (2DEG) sheet density decreases, the channel back-barrier caused by polarization-induced electric field in GaN provides better electron confinement. And under certain conditions the DH-structure shows bipolar characteristics, with an additional two-dimensional hole gas (2DHG) formed at GaN/AlGaN interface. The influence of the buffer Al content and GaN channel thickness on the 2DEG and 2DHG sheet densities are investigated, and the conditions for the disappearance of 2DHG are discussed. Also, the mobility inhibited by dislocation scattering is enhanced in DH-structure due to the enhancement of screening effect of the 2DEG

Low temperature route synthesis of SiC–Al2O3 hetero-structural nanofibers

International Nuclear Information System (INIS)

Dai, Xiao; Wang, Hao; Cao, Fengfeng; Yi, Qinghua; Cong, Shan; Wang, Yun; Song, Pingyuan; Zhai, Pengfei; Zou, Guifu; Dong, Chao

2014-01-01

SiC–Al 2 O 3 hetero-structural nanofibers have been synthesized by the chemical solution approach at 200 ° C. The diameters of nanofibers are in the range of 60–100 nm while the lengths are from tens of micrometers to hundreds of micrometers. The microstructural analysis shows that the fibers possess a like-epitaxial relationship between (104) of hexagonal Al 2 O 3 and (111) of cubic SiC. Additionally, the optical investigation of the nanofibers suggests there are some defects in the low annealing temperature synthesized SiC–Al 2 O 3 nanofibers. (paper)

The code of light: al-ghazali and al-suhrawardi

OpenAIRE

Gediminaitė, Barbora

2017-01-01

The Code of Light: Al-Ghazali and Al-Suhrawardi The Bachelor’s thesis The Code of Light in Islam: al-Ghazali and al-Suhrawardi presents a comparative study of light. The study analyses the philosophical systems of al-Ghazali and al-Suhrawardi through the reconstruction of the image of light and its operation principles. The main subject of the thesis are the attributes of light. The main problem of the research is the semantics and contextuality of light in Islamic theology and philosophy. Th...

Compressive Properties of PTFE/Al/Ni Composite Under Uniaxial Loading

Science.gov (United States)

Wang, Huai-xi; Li, Yu-chun; Feng, Bin; Huang, Jun-yi; Zhang, Sheng; Fang, Xiang

2017-05-01

To investigate the mechanical properties of pressed and sintered PTFE/Al/Ni (polytetrafluoroethylene/aluminum/nickel) composite, uniaxial quasi-static and dynamic compression experiments were conducted at strain rates from 10-2 to 3 × 103/s. The prepared samples were tested by an electrohydraulic press with 300 kN loading capacity and a split Hopkinson pressure bar (SHPB) device at room temperature. Experimental results show that PTFE/Al/Ni composite exhibits evident strain hardening and strain rate hardening. Additionally, a bilinear relationship between stress and {{log(}}\\dot{ɛ} ) is observed. The experimental data were fit to Johnson-Cook constitutive model, and the results are in well agreement with measured data.

La relación lenguaje y conocimiento y su aplicación al aprendizaje escolar The relationship between language and knowledge and its application to school learning

Directory of Open Access Journals (Sweden)

Ángela Camargo Uribe

2010-06-01

Full Text Available Este artículo expone tres aproximaciones teóricas que han sido propuestas para la comprensión de la relación entre el lenguaje y conocimiento: la del cognitivismo, la del socio constructivismo y la del socio constructivismo discursivo. Posteriormente, presenta secuencias de aula que ilustran cada uno de estos enfoques, a fin de analizar y evaluar cada postura desde el punto de vista del aprendizaje escolar. Finalmente, llega a conclusiones sobre las relaciones entre los tres enfoques considerados respecto de su aplicación específica al contexto pedagógico y didácticoThis paper explains three theoretical approaches that have been proposed to explain the relationship between language and knowledge: cognitivism, social constructivism and discursive constructivism. Later on, the paper presents different classroom dialogues and speech sequences that illustrate each approach to analyze and evaluate them from the point of view of school learning. Finally, some statements are about the relationships among the three approaches and with respect to their application to the classroom context

Pemikiran Filosofis Sadra Dalam Tafsir Al-Qur’an Al-Karim : Surah Al-’A‘la

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Kerwanto Kerwanto

2014-12-01

Full Text Available Abstrak : Dalam tafsir atas Surah al-’A‘lā, Mulla Sadra, melalui karyanya Tafsīr al Qur’ān al-Karīm, mengajak jiwa kita berpetualang menuju lapisan makna terdalam untuk mengenali realitas ketauhidan (al- mabdā’, kenabian (shirāth atau nubuwwah dan kebangkitan (ma‘ād dan mengulasnya secara filosofis. Penelitian ini merupakan suatu upaya untuk menggali manfaat dari aspek-aspek penting dari sumber-sumber keagamaan yang tergali dari petunjuk al Qur’an yang berpadu dengan prinsip- prinsip rasional filosofis dan pengalaman mistik (intuitif Sadra. Setiap bab pada tafsir ini diberikan judul dengan tasbīḥ (pernyataan pemujian dan pensucian, dengan tetap memaparkan beragam pokok persoalan terkait metafisika al-Qur’an. Prinsip-prinsip filosofis yang digunakan dalam risalah tafsir ini bisa menjadi salah satu bukti ketidakberjarakan antara filsafat dengan teks-teks keagamaan. Sadra menggunakan metode tafsir yang tetap menerima sisi lahiriah al-Qur’an, dan selanjutnya mencari misteri-misteri, rahasia-rahasia, dan dengan bantuan intelek (akal, intuisi dan iluminasi Tuhan untuk memperoleh realitas-realitas dan makna- makna dibalik selaput ekternalnya (aspek literalnyaKata kunci : Ḥikmah Muta’āliyah, irfan, al-mabdā’, kebangkitan setelah mati, nubuwwah, takwīl, gerak substansial (ḥarakah jawhariyyah, denotasi utama (al-maqshūd al-ashlī, penyempurnaan diri (takammul, tasbīḥ.  Abstract : In his commentary on Surah al-’ A‘lā, Mulla Sadra, through his Tafsīr al-Qur’ān al-Karīm invites our souls to ventureinto the deepest layers of meaning to recognize the reality of Divinity (al- mabdā’, prophethood (Ṣirāṭ or nubuwwah and resurrection (ma‘ād and discusses it in a more philosophical manner. This study is an attempt to explore the benefits of these important aspects of religious sources unearthed from Qur’anic injunctions combined with rational principles of philosophical and mystical experiences

A united refinement technology for commercial pure Al by Al-10Ti and Al-Ti-C master alloys

International Nuclear Information System (INIS)

Ma Xiaoguang; Liu Xiangfa; Ding Haimin

2009-01-01

Because flake-like TiAl 3 particles in Al-Ti-C master alloys prepared in a melt reaction method dissolve slowly when they are added into Al melt at 720 deg. C, Ti atoms cannot be released rapidly to play the assistant role of grain refinement, leading to a poor refinement efficiency of Al-Ti-C master alloys. A united refinement technology by Al-10Ti and Al-Ti-C master alloys was put forward in this paper. The rational combination of fine blocky TiAl 3 particles in Al-10Ti and TiC particles in Al-Ti-C can improve the nucleation rate of α-Al. It not only improves the grain refinement efficiency of Al-Ti-C master alloys, but also reduces the consumption

The Relationship between Compulsive Behaviour and Internet Addiction

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Maria Rosita Cecilia

2013-08-01

Full Text Available A variety of behavioural and emotional problems among university students is due to Internet Addiction (Alavi et al. 2012, Rusconi et al. 2012. In 2013 a survey is conducted on a sample of 532 students of University of L’Aquila. The purpose is to investigate Internet use patterns and the correlation between Internet Addiction disorder and compulsive behaviour. Two self-administered questionnaires are used: the Internet Addiction Test and the Cognitive Behavioural Assessment 2.0. 517 students show signs of Internet Addiction, which is moderate for 31% of respondents and severe for 1% of them. 5% shows intrusive thoughts and compulsive behaviours. The symptoms of obsessive-compulsive disorder are statistically associated with Internet Addiction (chi² test=23.53, p=0.000. Among young people there is a relationship between compulsive behaviour and Internet Addiction. This relationship has significant effects on treatment of Internet Addiction.

Liquidus projection of the Nb-Cr-Al system near the Al3(Nb,Cr) + Cr(Al,Nb) eutectic region

International Nuclear Information System (INIS)

Souza, S.A.; Ferrandini, P.L.; Nunes, C.A.; Coelho, A.A.; Caram, R.

2006-01-01

The system Nb-Cr-Al was investigated in the region near the Al 3 (Nb,Cr) + Cr(Al,Nb) eutectic and the liquidus projection of that region was determined based on the microstructural characterization of arc melted alloys. The characterization utilized scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), differential thermal analysis (DTA) and X-ray diffraction (XRD). The results allowed one to determine three primary solidification liquidus surfaces ((Cr,Al) 2 Nb, Cr(Al,Nb) and Al 3 (Nb,Cr)), that are originated from the binary systems Cr-Nb, Cr-Al and Al-Nb. It is proposed the occurrence of the invariant reaction L + (Cr,Al) 2 Nb ↔ Al 3 (Nb,Cr) + Cr(Al,Nb) and of a point of minimum, which involves a three phase reaction, L ↔ Al 3 (Nb,Cr) + Cr(Al,Nb). All alloys studied showed formation of the Al 3 (Nb,Cr) + Cr(Al,Nb) eutectic as the last solidification step with Al(Nb)Cr 2 precipitating from Cr(Al,Nb)

InAlN high electron mobility transistor Ti/Al/Ni/Au Ohmic contact optimisation assisted by in-situ high temperature transmission electron microscopy

International Nuclear Information System (INIS)

Smith, M. D.; Parbrook, P. J.; O'Mahony, D.; Conroy, M.; Schmidt, M.

2015-01-01

This paper correlates the micro-structural and electrical characteristics associated with annealing of metallic multi-layers typically used in the formation of Ohmic contacts to InAlN high electron mobility transistors. The multi-layers comprised Ti/Al/Ni/Au and were annealed via rapid thermal processing at temperatures up to 925 °C with electrical current-voltage analysis establishing the onset of Ohmic (linear IV) behaviour at 750–800 °C. In-situ temperature dependent transmission electron microscopy established that metallic diffusion and inter-mixing were initiated near a temperature of 500 °C. Around 800 °C, inter-diffusion of the metal and semiconductor (nitride) was observed, correlating with the onset of Ohmic electrical behaviour. The sheet resistance associated with the InAlN/AlN/GaN interface is highly sensitive to the anneal temperature, with the range depending on the Ti layer thickness. The relationship between contact resistivity and measurement temperature follow that predicted by thermionic field emission for contacts annealed below 850 °C, but deviated above this due to excessive metal-semiconductor inter-diffusion

Phase relationships in Cu-rich corner of the Cu-Cr-Zr phase diagram

International Nuclear Information System (INIS)

Zeng, K.J.; Haemaelaeinen, M.; Lilius, K.

1995-01-01

In the available experimental information on the Cu-Cr-Zr ternary system, there exist different opinions concerning the phase relationships in the Cu-rich corner of Cu-Cr-Zr phase diagram. Glazov et al. and Zakharov et al. investigated the Cu-rich corner of the Cu-Cr-Zr phase diagram within the composition range up to 3.5 Cr and 3.5 Zr (wt. %). A quasi-eutectic reaction L → (Cu) + αCr 2 Zr was observed to occur at 1,020 C and several isothermal sections were constructed within the temperature range from 600 to 1,000 C to show the (Cu)-αCr 2 Zr two phase equilibrium. Therefore, a pseudobinary Cu-Cr 2 Zr system was supposed. Afterwards, Dawakatsu et al, Fedorov et al, and Kuznetsov et al studied the cu-rich corner of the phase diagram in a wider composition range up to 5 Cr and 20 Zr (at.%). Contrary to Glazov et al. and Zakharov et al., they found no Cr 2 Zr phase in their samples. Hence, the pseudobinary Cu-Cr 2 Zr system does not exist. In this study an experimental investigation is presented on the phase relationships in Cu-rich corner of the Cu-Cr-Zr phase diagram at 940 C in order to clear up the confusion

PRÁCTICAS DE CONSUMO DE BEBIDAS ETÍLICAS EN UNA “CASA DE NEGOCIOS” PAMPEANA DE FINES DEL SIGLO XIX. ANÁLISIS DE PRECINTOS DE PLOMO Y DE FRAGMENTOS VÍTREOS (POSTA EL CALDÉN, DEPARTAMENTO DE REALICÓ, LA PAMPA / Alcohol consumption practices at a pampa´s ge

Directory of Open Access Journals (Sweden)

Virginia Pineau

2014-11-01

Full Text Available En el marco del proyecto Ubacyt F 095 que tiene como parte de sus objetivos estudiar y comprender el poblamiento del norte de la provincia de La Pampa posterior a las campañas militares de fines del siglo XIX, se presenta el análisis de los precintos de plomo y fragmentos vítreos provenientes del sitio Posta el Caldén (sección I, fracción A, lote 24. Dicho sitio se trata de una posta de caminos y casa de negocios ocupada hacia fines del siglo XIX. La misma pertenecía a una línea de postas entre las ciudades de Victorica (Provincia de La Pampa y General Villegas (Provincia de Buenos Aires. Se realizarán análisis morfológico – funcional, metalográfico mediante microscopia óptica (LM y electrónica de barrido (SEM y químico utilizando espectroscopia de rayos X dispersiva en energía (EDS de las piezas bajo estudio. El objetivo fue determinar tipos de bebidas alcohólicas consumidas y procedencia de las mismas. Se identificaron diversos tipos y marcas de bebidas de tenor etílico, se determinó que el material de confección de los precintos era de plomo recubierto con estaño típico de la técnica de confección denominada roll bonding. Esta información será de utilidad a la hora de estudiar las prácticas sociales de estos nuevos grupos de inmigrantes en combinación con las fuentes escritas y la historia oral.   Palabras Clave: Bebidas alcohólicas, Siglo XIX, La Pampa.     Abstract Within the framework of Ubacyt F 095 project that has as part of its aims to study the settlement of the northern province of La Pampa after the military campaigns of the late nineteenth century. We present the analysis of lead seals and fragments vitreous from the site Posta Caldén (Section I, Dept A, lot 24. This site is a crossroad post and a grocery store in the late nineteenth century. It belonged to a line of posts between the cities of Victorica (Province of La Pampa and General Villegas (Province of Buenos Aires. Morphological and

A united refinement technology for commercial pure Al by Al-10Ti and Al-Ti-C master alloys

Energy Technology Data Exchange (ETDEWEB)

Ma Xiaoguang [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Liu Xiangfa [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)], E-mail: xfliu@sdu.edu.cn; Ding Haimin [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China)

2009-03-05

Because flake-like TiAl{sub 3} particles in Al-Ti-C master alloys prepared in a melt reaction method dissolve slowly when they are added into Al melt at 720 deg. C, Ti atoms cannot be released rapidly to play the assistant role of grain refinement, leading to a poor refinement efficiency of Al-Ti-C master alloys. A united refinement technology by Al-10Ti and Al-Ti-C master alloys was put forward in this paper. The rational combination of fine blocky TiAl{sub 3} particles in Al-10Ti and TiC particles in Al-Ti-C can improve the nucleation rate of {alpha}-Al. It not only improves the grain refinement efficiency of Al-Ti-C master alloys, but also reduces the consumption.

Some morphometric relationships of hatchery reared male ...

African Journals Online (AJOL)

ajl yemi

2011-11-28

Nov 28, 2011 ... distributed exotic fishes in the world (Canonico et al.,. 2005). ... factor of a fish species are the two most significant biological .... and presented for 1773 marine and freshwater species by Froese .... size from the same and different habitats to validate ... relationships of fish species from Aegean Sea (Greece).

The Lost Caravan: The Rise and Fall of Al Qaeda in Iraq, 2003-2007

Science.gov (United States)

2010-06-01

classes and religious backgrounds and Sunnis took full advantage of the Ottoman educational system, sending their sons through the system to become...hostile environment.”93 Intercessory wasta on the other hand, “involves a protagonist intervening on behalf of a client to obtain an advantage for...known as al Qaeda in Iraq (AQI). The relationship of al Qaeda to AQI is similar to that of a corporation and an independent franchisee . The

Thermodynamic description of the Al-Cu-Yb ternary system supported by first-principles calculations

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Huang G.

2016-01-01

Full Text Available Phase relationships of the ternary Al-Cu-Yb system have been assessed using a combination of CALPHAD method and first principles calculations. A self-consistent thermodynamic parameter was established based on the experimental and theoretical information. Most of the binary intermetallic phases, except Al3Yb, Al2Yb, Cu2Yb and Cu5Yb, were assumed to be zero solubility in the ternary system. Based on the experimental data, eight ternary intermetallic compounds were taken into consideration in this system. Among them, three were treated as line compounds with large homogeneity ranges for Al and Cu. The others were treated as stoichiometric compounds. The calculated phase diagrams were in agreement with available experimental and theoretical data.

Relationships between brightness of nighttime lights and population density

Science.gov (United States)

Naizhuo, Z.

2012-12-01

Brightness of nighttime lights has been proven to be a good proxy for socioeconomic and demographic statistics. Moreover, the satellite nighttime lights data have been used to spatially disaggregate amounts of gross domestic product (GDP), fossil fuel carbon dioxide emission, and electric power consumption (Ghosh et al., 2010; Oda and Maksyutov, 2011; Zhao et al., 2012). Spatial disaggregations were performed in these previous studies based on assumed linear relationships between digital number (DN) value of pixels in the nighttime light images and socioeconomic data. However, reliability of the linear relationships was never tested due to lack of relative high-spatial-resolution (equal to or finer than 1 km × 1 km) statistical data. With the similar assumption that brightness linearly correlates to population, Bharti et al. (2011) used nighttime light data as a proxy for population density and then developed a model about seasonal fluctuations of measles in West Africa. The Oak Ridge National Laboratory used sub-national census population data and high spatial resolution remotely-sensed-images to produce LandScan population raster datasets. The LandScan population datasets have 1 km × 1 km spatial resolution which is consistent with the spatial resolution of the nighttime light images. Therefore, in this study I selected 2008 LandScan population data as baseline reference data and the contiguous United State as study area. Relationships between DN value of pixels in the 2008 Defense Meteorological Satellite Program's Operational Linescan System (DMSP-OLS) stable light image and population density were established. Results showed that an exponential function can more accurately reflect the relationship between luminosity and population density than a linear function. Additionally, a certain number of saturated pixels with DN value of 63 exist in urban core areas. If directly using the exponential function to estimate the population density for the whole brightly

United modification of Al-24Si alloy by Al-P and Al-Ti-C master alloys

Institute of Scientific and Technical Information of China (English)

韩延峰; 刘相法; 王海梅; 王振卿; 边秀房; 张均艳

2003-01-01

The modification effect of a new type of Al-P master alloy on Al-24Si alloys was investigated. It is foundthat excellent modification effect can be obtained by the addition of this new type of A1-P master alloy into Al-24Simelt and the average primary Si grain size is decreased below 47 μm from original 225 μm. It is also found that theTiC particles in the melt coming from Al8Ti2C can improve the modification effect of the Al-P master alloy. Whenthe content of TiC particles in the Al-24Si melt is 0.03 %, the improvement reaches the maximum and keeps steadywith increasing content of TiC particles. Modification effect occurs at 50 min after the addition of the Al-P master al-loy and TiC particles, and keeps stable with prolonging holding time.

Nanoporous Al sandwich foils using size effect of Al layer thickness during Cu/Al/Cu laminate rolling

Science.gov (United States)

Yu, Hailiang; Lu, Cheng; Tieu, A. Kiet; Li, Huijun; Godbole, Ajit; Kong, Charlie

2018-06-01

The roll bonding technique is one of the most widely used methods to produce metal laminate sheets. Such sheets offer interesting research opportunities for both scientists and engineers. In this paper, we report on an experimental investigation of the 'thickness effect' during laminate rolling for the first time. Using a four-high multifunction rolling mill, Cu/Al/Cu laminate sheets were fabricated with a range of thicknesses (16, 40, 70 and 130 μm) of the Al layer. The thickness of the Cu sheets was a constant 300 μm. After rolling, TEM images show good bonding quality between the Cu and Al layers. However, there are many nanoscale pores in the Al layer. The fraction of nanoscale pores in the Al layer increases with a reduction in the Al layer thickness. The finite element method was used to simulate the Cu/Al/Cu rolling process. The simulation results reveal the effect of the Al layer thickness on the deformation characteristics of the Cu/Al/Cu laminate. Finally, we propose that the size effect of the Al layer thickness during Cu/Al/Cu laminate rolling may offer a method to fabricate 'nanoporous' Al sandwich laminate foils. Such foils can be used in electromagnetic shielding of electrical devices and noisy shielding of building.

Synthesis of c-axis oriented AlN thin films on different substrates: A review

International Nuclear Information System (INIS)

Iriarte, G.F.; Rodriguez, J.G.; Calle, F.

2010-01-01

Highly c-axis oriented AlN thin films have been deposited by reactive sputtering on different substrates. The crystallographic properties of layered film structures consisting of a piezoelectric layer, aluminum nitride (AlN), synthesized on a variety of substrates, have been examined. Aluminum nitride thin films have been deposited by reactive pulsed-DC magnetron sputtering using an aluminum target in an Ar/N 2 gas mixture. The influence of the most critical deposition parameters on the AlN thin film crystallography has been investigated by means of X-ray diffraction (XRD) analysis of the rocking curve Full-Width at Half Maximum (FWHM) of the AlN-(0 0 0 2) peak. The relationship between the substrate, the synthesis parameters and the crystallographic orientation of the AlN thin films is discussed. A guide is provided showing how to optimize these conditions to obtain highly c-axis oriented AlN thin films on substrates of different nature.

Structural stability and electronic properties of AlCu3, AlCu2Zr in AlZr3: Stabilnost strukture in elektronske lastnosti AlCu3, AlCu2Zr in AlZr3:

OpenAIRE

Cheng, Rong; Wu, Xiao-Yu

2013-01-01

First-principles calculations were performed to study the alloying stability and electronic structure of the Al-based intermetallic compounds AlCusub3, AlCusub{2}Zr and AlZrsub3. The results show that the lattice parameters obtained after the full relaxation of the crystalline cells are consistent with the experimental data, and these intermetallics have a strong alloying ability and structural stability due to their negative formation energies and their cohesive energies. A further analysis ...

Ventajas Del Perenox. Fungicida de la Casa COOPER sobre el Caldo Bordelés y otros productos a base de cobre.

Directory of Open Access Journals (Sweden)

Universidad Nacional de Colombia Facultad de Ciencias Agrarias

1941-10-01

Full Text Available "Perenox" es un Oxido de Cobre especialmente preparado, presentado en la forma de un polvo dispersivo extraordinariamente soluble en agua. Contiene 50 % de Cobre, mientras que los cristales del Sulfato de Cobre sólo contienen 25%, Una libra de "Perenox" reemplaza a lo menos 4 libras de Sulfato de Cobre y la correspondiente cantidad de cal y adherentes necesarios para la preparación del Caldo Bordelés. El "Perenox" se puede usar en todos esos casos en que entra el empleo del Caldo Bordelés, como por ejemplo para fumigar contra la "Gota" de la papa, la "Sigatoka" del banano, enfermedades de los cafetos, árboles de cacao, árboles frutales, etc. Se puede agregar al "Perenox" arseniato de plomo u otras substancias cuando se desee también controlar plagas de insectos.

Nonlinear relationship between the Product Consistency Test (PCT) response and the Al/B ratio in a soda-lime aluminoborosilicate glass

Energy Technology Data Exchange (ETDEWEB)

Farooqi, Rahmat Ullah, E-mail: rufarooqi@postech.ac.kr [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Hrma, Pavel [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Pacific Northwest National Laboratory, Richland, WA (United States)

2016-06-15

We have investigated the effect of Al/B ratio on the Product Consistency Test (PCT) response. In an aluminoborosilicate soda-lime glass based on a modified International Simple Glass, ISG-3, the Al/B ratio varied from 0 to 0.55 (in mole fractions). In agreement with various models of the PCT response as a function of glass composition, we observed a monotonic increase of B and Na releases with decreasing Al/B mole ratio, but only when the ratio was higher than 0.05. Below this value (Al/B < 0.05), we observed a sharp decrease that we attribute to B in tetrahedral coordination.

Gray matter perfusion correlates with disease severity in ALS.

Science.gov (United States)

Rule, Randall R; Schuff, Norbert; Miller, Robert G; Weiner, Michael W

2010-03-09

The goal of this study is to determine if regional brain perfusion, as measured by arterial spin labeling (ASL) MRI, is correlated with clinical measures of amyotrophic lateral sclerosis (ALS) disease severity. The presence of such a relationship would indicate a possible role for ASL perfusion as a marker of disease severity and upper motor neuron involvement in ALS. Disease severity was assessed in 16 subjects with ALS (age 54 +/- 11) using the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS) and the pulmonary function measure, forced vital capacity (FVC). Upper motor neuron involvement was assessed by testing rapid tapping of the fingers and feet. Magnetic resonance perfusion images were coregistered with structural T1-weighted MRI, corrected for partial volume effects using the structural images and normalized to a study-specific atlas. Correlations between perfusion and ALS disease severity were analyzed, using statistical parametric mapping, and including age as a factor. Analyses were adjusted for multiple clusters. ALS severity, as measured by the ALSFRS and FVC, was correlated with gray matter perfusion. This correlation was predominantly observed in the hemisphere contralateral to the more affected limbs. ALSFRS scores correlated with perfusion in the contralateral frontal and parietal lobe (p frontal lobe (p frontal lobe (p Upper motor neuron involvement, as measured by rapid finger tapping, correlated bilaterally with perfusion in the middle cingulate gyrus (p < 0.001). Amyotrophic lateral sclerosis (ALS) severity is correlated with brain perfusion as measured by arterial spin labeling (ASL) perfusion. This correlation appears to be independent of brain atrophy. ASL perfusion may be a useful tool for monitoring disease progression and assessing treatment effects in ALS.

The Relationship between Anterior Chamber Depth, Axial Length and Intraocular Lens Power among Candidates for Cataract Surgery.

Science.gov (United States)

Sedaghat, Mohammad Reza; Azimi, Ali; Arasteh, Peyman; Tehranian, Naghmeh; Bamdad, Shahram

2016-10-01

Basic anatomical parameters in ophthalmology are variable in different countries according to ethnic groups, genetics and some environmental factors. The aim of this study was to determine the relationship between axial length (AL), anterior chamber depth (ACD) and intraocular lens power (IOL) in a referral center from eastern Iran among patients who had cataract surgery, in comparison to studies from other regions of the world. In a cross-sectional retrospective study from 2011 to 2013, the records of 698 cataract patients referring to Khatam Al Anbia general hospital in Mashhad, Iran were evaluated. We divided patients, based on their AL and ACD, into three separate groups and compared their results. The SPSS software was used for data analysis. The Chi-Square test and the Independent-samples t-test were used to compare qualitative and quantitative data between two groups, respectively. The Kendall and the Pearson product-moment correlation tests were used to assess the relationship between AL and ACD. The linear Regression model was used to obtain a mathematical model to estimate ACD, using AL, age and sex. Among individuals who had normal AL (between 22-24.5mm), there was a positive correlation between AL and ACD (p24.5mm), no significant correlation was detected. We also found that older people have shorter AL (p=0.001 and r=-0.287). Men have an average longer AL (23.7±2.4mm vs. 22.9±2.1mm; pworld and although some anatomical variations may exist regarding ophthalmic anatomy, factors like race and geographical area have little effect on the relationship between ACD, AL and IOL power calculation, furthermore our results support the use of third and fourth generation formulas for IOL power calculation.

Precipitation of grain boundary α in a laser deposited compositionally graded Ti-8Al-xV alloy - an orientation microscopy study

International Nuclear Information System (INIS)

Banerjee, R.; Bhattacharyya, D.; Collins, P.C.; Viswanathan, G.B.; Fraser, H.L.

2004-01-01

A graded ternary Ti-8Al-xV alloy (all compositions in wt%) has been deposited using the laser engineered net-shaping (LENS TM ) process. A compositional gradient in the alloy, from binary Ti-8Al to Ti-8Al-20V, has been achieved within a length of ∼25 mm. The feedstock used for depositing the graded alloy consisted of elemental Ti, Al, and V powders. Due to the columnar growth morphology of the β grains in these LENS TM deposited Ti alloys, the same prior β grain boundary often extends across lengths ∼10 mm. Using orientation microscopy techniques in a scanning electron microscope, the crystallography of precipitation of grain boundary α across the same boundary with changing composition has been investigated in detail. It was observed that while most grain boundary α precipitates maintain a Burgers or near-Burgers orientation relationship with only one of the β grains, a few of these precipitates develop a Burgers orientation relationship with the other β grain. In some rare instances, the grain boundary α did not develop a Burgers or near-Burgers orientation relationship with either β grains. Interestingly, in many cases while the grain boundary α maintained Burgers relationship with one of the β grains, precipitates of two different variants decorated the boundary, in a near-alternate fashion

/Cu-Al System

Science.gov (United States)

Kish, Orel; Froumin, Natalya; Aizenshtein, Michael; Frage, Nachum

2014-05-01

Wettability and interfacial interaction of the Ta2O5/Cu-Al system were studied. Pure Cu does not wet the Ta2O5 substrate, and improved spreading is achieved when relatively a high fraction of the active element (~40 at.% Al) was added. The Al2O3 and AlTaO4 phases were observed at the Ta2O5/Cu-Al interface. A thermodynamic evaluation allowed us to suggest that the lack of wetting bellow 40 at.% Al is due to the presence of a native oxide, which covers the drop. The conditions of the native oxide decomposition and the formation of the volatile Al2O suboxide strongly depend on the vacuum level during sessile drop experiments and the composition of the Cu-Al alloy. In our case, Al contents greater than 40% provides thermodynamic conditions for the formation of Al2O (as a result of Al reaction with Al2O3) and the drop spreading. It was suggested that the final contact angle in the Ta2O5/Cu-Al system (50°) is determined by Ta adsorption on the newly formed alumina interlayer.

Review article: RE-SiAlONa¤b- composites. Formation, thermal stability, phase relationships, reaction densification Artigo revisão: compósitos TR a¤b SiAlON. Formação, estabilidade térmica, relações de fases, densificação por reação

Directory of Open Access Journals (Sweden)

V. A. Izhevskiy

1999-02-01

Full Text Available In view of the considerable progress that has been made over the last several years on the fundamental understanding of phase relationships, microstructural design, and tailoring of properties for specific applications of rare-earth doped SiAlONs, a clear review of current understanding of the basic regularities lying behind the processes that take place during sintering of SiAlONs is timely. Alternative secondary phase development, mechanism and full reversibility of thea«btransformation in relation with the phase assemblage evolution are elucidated. Reaction sintering of multicomponent SiAlONs is considered with regard of wetting behavior of silicate liquid phases formed on heating. Regularities of SiAlON’s behavior and stability are tentatively explained in terms of RE-element ionic radii and acid/base reaction principle.Em vista do considerável progresso obtido nos últimos anos quanto à relação entre fases, o design microestrutural e a otimização de propriedades para aplicações específicas de SiAlONs dopados com elementos de terras-raras, se faz necessário uma clara revisão dos mecanismos envolvidos nos processos que ocorrem durante a sinterização dos SiAlONs. O desenvolvimento de segundas fases alternativas, os mecanismos e a completa reversibilidade da transformaçãoa«b, em relação ao conjunto das fases são elucidados. Sinterização por reação de SiAlONs multi-componentes é analisada em relação à molhabilidade da fase líquida a base de silicato formada no aquecimento. Propõe-se uma explicação para a regularidade e estabilidade do comportamento dos SiAlONs em termos do raio iônico dos elementos de terras-raras e do princípio de reação ácido/base.

Metodologi Kitab Ma‘alim al-Tanzil Karya Al-Bagawiy

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M. Rusydi Khalid

2017-12-01

This study aims to describe the metodology of Ma'a> lim al-tanzi>l book by al-Bagawi. The book is one of the books of exegesis written on the basis of hadith, which by the commentary scholars recognized avoided from heresy and weak hadith. The author of this book is Imam Abu Humaid Hussein bin Mas‘u>d al-Farra>’ Al-Bagawi al-Syafi‘i>, died in the year 510 H. This exegesis book combines the interpretation of the companions, tabi‘i>n, and tabi‘i> tabi‘i>n. Interpretation is broken down with easy, simple, and concise diction choices. The stoning of the interpretation of the salaf scholars without mentioning the sanad as already mentioned in the introduction to his book. This book was first printed in one edition with the exegesis book of Ibn Kas}i>r and al-kha>zin. This book interprets the Qur'an analytically from the beginning to the end of the surah by using the method of interpretation based on the hadith, namely by mentioning the arguments of the hadith sahih, the fatwa of the companions and the tabi‘i>n. The characteristic or purpose of this book is fiqh oriented, which tends to the Shafi‘i fiqh.   Abstrak Tulisan ini mendeskripsikan metode penafsiran dalam kitab Ma’a>lim al-tanzi>l karya al-bagawi. Kitab tafsir ini merupakan salah satu di antara kitab-kitab tafsir yang ditulis berdasarkan riwayat, yang oleh para ulama tafsir diakui terhindar dari bid’ah dan hadis dhaif (lemah. Penulis buku ini adalah Imam Abu Muhammad Husain bin Mas‘u>d al-Farra>‘ al-Bagawi al-Syafi‘i>, wafat pada tahun 510 H. Kitab ini adalah kitab pertengahan yang mengutip penafsiran para Sahabat, ta>bi‘i>n, dan tabi‘i ta>bi‘i>n. Penafsiran diuraikan dengan pilihan diksi yang mudah, sederhana, dan ringkas. Penukilan dari interpretasi ulama salaf tanpa menyebutkan sanad karena telah disebutkan dalam pendahuluan bukunya. Buku ini pertama kali dicetak dalam satu edisi dengan tafsir Ibn Kas\\i>r dan tafsir al-Kha>zin. Kitab ini menafsirkan al-Qur’an secara

EVALUACIÓN DE LA ELECTRORREMEDIACIÓN DE ANDISOLES CONTAMINADOS, MEDIANTE EL ANÁLISIS DE LAS SOLUCIONES DE LAVADO

Directory of Open Access Journals (Sweden)

Juan A. Rodríguez V.

2003-06-01

Full Text Available Se analizó la composición de soluciones de lavado provenientes de las cámaras de electrodos de una celda de remediación a nivel de laboratorio. Se estudió el movimiento de iones nitrato y plomo como contaminantes de suelos de la región (Andisol.Para los estudios se analizaron conjuntamente medidas de pH, conductiVidad, turbidez, concentración de contaminantes y corriente dé electrólisis.Se comprueba que, para las condiciones experimentales empleadas, los iones nitrato se mueven libremente y son fácilmente removidos del suelo, mientras que el catión plomo es parcialmente retenido, y la cantidad de metal que se moviliza es obtenido finalmente bajo formas insolubles dado el valor de pH generado en la cámara del cátodo.

ALS Association

Science.gov (United States)

... toward a world without ALS! Walk to Defeat ALS® Walk to Defeat ALS® draws people of all ... We need your help. I Will Advocate National ALS Registry The National ALS Registry is a congressionally ...

AlN nanoparticle-reinforced nanocrystalline Al matrix composites: Fabrication and mechanical properties

International Nuclear Information System (INIS)

Liu, Y.Q.; Cong, H.T.; Wang, W.; Sun, C.H.; Cheng, H.M.

2009-01-01

To improve the specific strength and stiffness of Al-based composites, AlN/Al nanoparticles were in-situ synthesized by arc plasma evaporation of Al in nitrogen atmosphere and consolidated by hot-pressing to fabricate AlN nanoparticle-reinforced nanocrystalline Al composites (0-39 vol.% AlN). Microstructure characterization shows that AlN nanoparticles homogeneously distribute in the matrix of Al nanocrystalline, which forms atomically bonded interfaces of AlN/Al. The hardness and the elastic modulus of the nanocomposite have been improved dramatically, up to 3.48 GPa and 142 GPa, respectively. Such improvement is believed to result from the grain refinement strengthening and the interface strengthening (load transfer) between the Al matrix and AlN nanoparticles

Comparison of one and two-neutron transfer near the Coulomb barrier for the 27Al(18O, 16O)29Al, 27Al(18O, 17O)28Al and 27Al(13C, 12C)28Al reactions

International Nuclear Information System (INIS)

Schiller, S.A.; Eck, J.S.

1975-01-01

Total reaction cross sections for the transfer reactions 27 Al( 18 O, 16 O) 29 Al, 27 Al( 18 O, 17 O) 28 Al and 27 Al( 13 C, 12 C) 28 Al are reported for center-of-mass energies between 13 and 20 MeV for 18 O projectiles and between 11 and 17.5 MeV for 13 C projectiles. The reaction products, 29 Al, and 28 Al, beta decay to 29 Si and 28 Si, respectively, and the subsequent γ decays of 29 Si and 28 Si were measured. Due to the relatively long beta decay half lives, data were taken in a beam-off mode, resulting in very clean spectra. Total cross sections were calculated and compared with a theoretical model for barrier penetration proposed by C.Y. Wong. Differences between 18 O induced one and two-neutron total transfer reaction cross sections are discussed. (orig.) [de

Synchrotron-based XPS studies of AlGaN and GaN surface chemistry and its relationship to ion sensor behaviour

Energy Technology Data Exchange (ETDEWEB)

Khir, Farah Liyana Muhammad, E-mail: 21001899@student.uwa.edu.au [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); Myers, Matthew, E-mail: Matt.Myers@csiro.au [School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); CSIRO Earth Science and Resource Engineering, Kensington, Western Australia 6151 (Australia); Podolska, Anna [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); Department of Exploration Geophysics, Curtin University of Technology, 26 Dick Perry Avenue, ARRC, Kensington, Western Australia 6151 (Australia); Sanders, Tarun Maruthi [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); Baker, Murray V., E-mail: murray.baker@uwa.edu.au [School of Chemistry and Biochemistry, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); Nener, Brett D., E-mail: brett.nener@uwa.edu.au [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia); Parish, Giacinta, E-mail: giacinta.parish@uwa.edu.au [School of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Hwy., Crawley, Western Australia 6009 (Australia)

2014-09-30

Highlights: • Soft X-ray was used to study the surface chemistry of GaN and AlGaN. • The surface chemistry and sensor behaviour were investigated. • The oxide of aluminum is significantly more reactive than gallium. • The Cl{sup −} ions are greater in GaN samples compared to AlGaN samples. - Abstract: Soft X-ray photoelectron spectroscopy was used to investigate the fundamental surface chemistry of both AlGaN and GaN surfaces in the context of understanding the behaviour of AlGaN/GaN heterostructures as chemical field-effect transistor (CHEMFET) ion sensors. AlGaN and GaN samples were subjected to different methods of oxide growth (native oxide and thermally grown oxide) and chemical treatment conditions. Our investigations indicate that the etching of the oxide layer is more pronounced with AlGaN compared to GaN. Also, we observed that chloride ions have a greater tendency to attach to the GaN surface relative to the AlGaN surface. Furthermore, chloride ions are comparatively more prevalent on surfaces treated with 5% HCl acid solution. The concentration of chloride ions is even higher on the HCl treated native oxide surface resulting in a very clear deconvolution of the Cl 2p{sub 1/2} and Cl 2p{sub 3/2} peaks. For GaN and AlGaN surfaces, a linear response (e.g. source-drain current) is typically seen with variation in pH of buffered solutions with constant reference electrode voltage at the surface gate; however, an inverted bath-tub type response (e.g. a maximum at neutral pH and lower values at pH values away from neutral) and a general tendency to negative charge selectivity has been also widely reported. We have shown that our XPS investigations are consistent with the different sensor response reported in the literature for these CHEMFET devices and may help to explain the differing response of these materials.

The preferential orientation and lattice misfit of the directionally solidified Fe-Al-Ta eutectic composite

Science.gov (United States)

Cui, Chunjuan; Wang, Pei; Yang, Meng; Wen, Yagang; Ren, Chiqiang; Wang, Songyuan

2018-01-01

Fe-Al intermetallic compound has been paid more attentions recently in many fields such as aeronautic, aerospace, automobile, energy and chemical engineering, and so on. In this paper Fe-Al-Ta eutectic was prepared by a modified Bridgman directional solidification technique, and it is found that microstructure of the Fe-Al-Ta eutectic alloy transforms from the broken-lamellar eutectic to cellular eutectic with the increase of the solidification rate. In the cellular eutectic structure, the fibers are parallel to each other within the same grain, but some fibers are deviated from the original orientation at the grain boundaries. To study the crystallographic orientation relationship (OR) between the two phases, the preferential orientation of the Fe-Al-Ta eutectic alloy at the different solidification rates was studied by Selected Area Electron Diffraction (SAED). Moreover, the lattice misfit between Fe2Ta(Al) Laves phase and Fe(Al,Ta) matrix phase was calculated.

Al-matrix composite materials reinforced by Al-Cu-Fe particles

International Nuclear Information System (INIS)

Bonneville, J; Laplanche, G; Joulain, A; Gauthier-Brunet, V; Dubois, S

2010-01-01

Al-matrix material composites were produced using hot isostatic pressing technique, starting with pure Al and icosahedral (i) Al-Cu-Fe powders. Depending on the processing temperature, the final reinforcement particles are either still of the initial i-phase or transformed into the tetragonal ω-Al0 0.70 Cu 0.20 Fe 0.10 crystalline phase. Compression tests performed in the temperature range 293K - 823K on the two types of composite, i.e. Al/i and Al/ω, indicate that the flow stress of both composites is strongly temperature dependent and exhibit distinct regimes with increasing temperature. Differences exist between the two composites, in particular in yield stress values. In the low temperature regime (T ≤ 570K), the yield stress of the Al/ω composite is nearly 75% higher than that of the Al/i composite, while for T > 570K both composites exhibit similar yield stress values. The results are interpreted in terms of load transfer contribution between the matrix and the reinforcement particles and elementary dislocation mechanisms in the Al matrix.

Piezo-tunnel effect in Al/Al2O3/Al junctions elaborated by atomic layer deposition

Science.gov (United States)

Rafael, R.; Puyoo, E.; Malhaire, C.

2017-11-01

In this work, the electrical transport in Al/Al2O3/Al junctions under mechanical stress is investigated in the perspective to use them as strain sensors. The metal/insulator/metal junctions are elaborated with a low temperature process (≤200 °C) fully compatible with CMOS back-end-of-line. The conduction mechanism in the structure is found to be Fowler-Nordheim tunneling, and efforts are made to extract the relevant physical parameters. Gauge factors up to -32.5 were found in the fabricated devices under tensile stress. Finally, theoretical mechanical considerations give strong evidence that strain sensitivity in Al/Al2O3/Al structures originates not only from geometrical deformations but also from the variation of interface barrier height and/or effective electronic mass in the tunneling oxide layer.

Structure-property relationships of mullite-SiC-Al{sub 2}O{sub 3}–ZrO{sub 2} composites developed during carbothermal reduction of aluminosilicate minerals

Energy Technology Data Exchange (ETDEWEB)

Seifollahzadeh, P., E-mail: Pseifollahzadeh.mat@stu.yazd.ac.ir; Kalantar, M.; Ghasemi, S.S.

2015-10-25

Evolution of SiC and ZrO{sub 2} in the matrix of Al{sub 2}O{sub 3} or mullite have been reported to enhance a higher toughness, good thermal shock resistance (lowering thermal expansion and improving thermal conductivity) and improved creep resistance of composite materials. In this study, the structure-property relationships of mullite-Al{sub 2}O{sub 3} matrix composites have been investigated in conjunction with the evolution of reinforcing phases such as SiC–ZrO{sub 2} by an economical heat treatment process called carbothermal reduction of inorganic minerals (Kaolinite, Andalusite, Zircon). The influence of starting materials in relation with the variation in molar ratio of C/SiO{sub 2} on the phase composition, microstructures, physical and mechanical properties have been studied. Light microscopy has been supplemented with scanning electron microscopy, XRD analysis, differential thermal and thermal gravity analysis to follow the structure-property relationships. The experimental results show that with increasing of C/SiO{sub 2} ratio in starting materials, very fine SiC whiskers have been formed in the microstructures. Moreover, the densification and strength are considerable higher for ZrO{sub 2} + SiC containing composites in comparison to that of only SiC added ones. Furthermore, it has been found that the appropriate ratio of C/SiO{sub 2} with the associated firing temperature to develop a higher densification and SiC crystallization have been related to the 3.5, 1550 °C for kaolinite, 3.5, 1450 °C for zircon and 5.5, 1600 °C for andalusite containing composite samples, respectively. - Highlights: • In-situ formation of SiC whiskers in matrix of alumina + mullite composites. • Advantage of availability, abundance and economical for starting materials. • Lack of environmental problems in comparable of utilization of whiskers directly. • A mixture of coke and alumina as a protective layer instead of inert atmosphere. • Fabrication of advanced

Study on superheat of TiAl melt during cold crucible levitation melting. TiAl no cold crucible levitation yokai ni okeru yoto kanetsudo no kenkyu

Energy Technology Data Exchange (ETDEWEB)

Miwa, K.; Kobayashi, K.; Ninomiya, M. (Government Industrial Research Institute, Nagoya, Nagoya (Japan))

1992-06-20

Investigations were given on effects of test sample weights and sample positions in cold crucibles on superheat of melts when the intermetallic compound TiAl is melted using cold crucible levitation melting process, one of noncontaminated melting processes. The cold crucibles used in the experiment are a water-cooled copper crucible with an inner diameter of 42 mm and a length of 140 mm, into which a column-like ingot sample with an outer diameter of 32 mm (Al containing Ti at 33.5% by mass) was put and melted using the levitation melting. Comparisons and discussions were given on the relationship between sample weights and melt temperatures, the relationship between positions of the inserted samples and melt temperatures, and the state of contamination at melting of casts obtained from the melts resulted from the levitation melting and high-frequency melting poured into respective ceramic dies. Elevating the superheat temperature of the melts requires optimizing the sample weights and positions. Melt temperatures were measured using a radiation thermometer and a thermocouple, and the respective measured values were compared. 7 refs., 4 figs., 1 tab.

Generation and evolution of nanoscale AlP and Al{sub 13}Fe{sub 4} particles in Al-Fe-P system

Energy Technology Data Exchange (ETDEWEB)

Qiao, Huan; Gao, Tong; Zhu, Xiangzhen; Wu, Yuying; Qian, Zhao; Liu, Xiangfa, E-mail: xfliu@sdu.edu.cn

2015-02-15

Highlights: • Diffusion and gradual solid reactions between Al and Fe{sub x}P phases in Al-Fe-P alloy were investigated. • Nanoscale AlP clusters are in-situ generated and evolve during the whole process. • This novel Al-Fe-P alloy has an excellent low-temperature refining performance on hypereutectic Al-Si alloy. - Abstract: In this paper, the gradual solid reactions between Al and Fe{sub x}P phases in Al-Fe-P alloy were investigated. The results show that the whole reaction process undergoes four main stages: the diffusion of Al atom, the generation of (Al, Fe, P) intermediate compound, the precipitation of nano AlP and Al{sub 13}Fe{sub 4} clusters and their growth to submicron particles. The microstructure of Fe-P particles evolves from the “egg-type”, the “sponge-type” to the “sesame-cake” structure. AlP and Al{sub 13}Fe{sub 4} nano phases have in-situ generated and evolved during the whole process. The gradual reaction mechanism has been discussed. Furthermore, a novel Al-Fe-P alloy which contains (Al, Fe, P) intermediate compounds and nano AlP particles has been synthesized and its low-temperature refining performance on A390 alloy has also been investigated.

Lead Poisoning (For Parents)

Science.gov (United States)

... Staying Safe Videos for Educators Search English Español Lead Poisoning KidsHealth / For Parents / Lead Poisoning What's in ... Print en español La intoxicación por plomo About Lead Poisoning If you have young kids, it's important ...

Japanese version of the ALS-FTD-Questionnaire (ALS-FTD-Q-J).

Science.gov (United States)

Watanabe, Yasuhiro; Beeldman, Emma; Raaphorst, Joost; Izumi, Yuishin; Yoshino, Hiide; Masuda, Michihito; Atsuta, Naoki; Ito, Satoru; Adachi, Tadashi; Adachi, Yoshiki; Yokota, Osamu; Oda, Masaya; Hanashima, Ritsuko; Ogino, Mieko; Ichikawa, Hiroo; Hasegawa, Kazuko; Kimura, Hideki; Shimizu, Toshio; Aiba, Ikuko; Yabe, Hayato; Kanba, Makoto; Kusumi, Kimiyoshi; Aoki, Tetsuya; Hiroe, Yu; Watanabe, Hirohisa; Nishiyama, Kazutoshi; Nomoto, Masahiro; Sobue, Gen; Nakashima, Kenji

2016-08-15

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) share common clinical, genetic and neuropathological features. Some ALS patients have behavioral/personality changes, which could result in significant obstacles in the care provided by family members and caregivers. An easy screening tool would contribute greatly to the evaluation of these symptoms. We translated the ALS-FTD-Questionnaire, developed in the Netherlands, into Japanese (ALS-FTD-Q-J) and examined the clinimetric properties (internal consistency, construct and clinical validity). Patients with ALS and/or behavioral variant FTD (bvFTD) were evaluated alongside healthy controls in this multicenter study. All ALS patients, regardless of bvFTD status, were further evaluated by the frontal behavioral inventory (FBI) and for frontal/executive function, cognition, anxiety/depression, and motor functions. Data from 146 subjects were analyzed: ALS (92), ALS-bvFTD (6), bvFTD (16), and healthy controls (32). The internal consistency of the ALS-FTD-Q-J was good (Cronbach α=0.92). The ALS-FTD-Q-J showed construct validity as it exhibited a high correlation with the FBI (r=0.79). However, correlations were moderate with anxiety/depression and low with cognitive scales, in contrast to the original report, i.e. a moderate correlation with cognition and a low correlation with anxiety/depression. The ALS-FTD-Q-J discriminated ALS patients from (ALS-)bvFTD patients and controls. Thus, the ALS-FTD-Q-J is useful for evaluating Japanese ALS/FTD patients. Copyright © 2016 Elsevier B.V. All rights reserved.

Radiation detection with Nb/Al-AlOx/Al/Nb superconducting tunnel junctions

International Nuclear Information System (INIS)

Matsumura, Atsuki; Takahashi, Toru; Kurakado, Masahiko

1992-01-01

Superconductor radiation detectors have the possibility of 20-30 times better energy resolution than that of a high resolution Si detector. We fabricated Nb/Al-AlOx/Al/Nb superconducting tunnel junctions with low leakage current. X rays were detected with large area junctions of 178x178 μm 2 . High energy resolution of 160 eV for 5.9 keV was obtained. We also fabricated series connected junctions which covers a rather large area of 4x4 mm 2 . α particles injected into the rear substrate were detected using nonthermal phonons induced by the radiations in the substrate. (author)

ALS-Plus Syndrome: Non-Pyramidal Features in a Large ALS Cohort

Science.gov (United States)

McCluskey, Leo; Vandriel, Shannon; Elman, Lauren; Van Deerlin, Vivianna M.; Powers, John; Boller, Ashley; Wood, Elisabeth McCarty; Woo, John; McMillan, Corey T.; Rascovsky, Katya; Grossman, Murray

2014-01-01

Objective Autopsy studies show widespread pathology in amyotrophic lateral sclerosis (ALS), but clinical surveys of multisystem disease in ALS are rare. We investigated ALS-Plus syndrome, an understudied group of patients with clinical features extending beyond pyramidal and neuromuscular systems with or without cognitive/behavioral deficits. Methods In a large, consecutively-ascertained cohort of 550 patients with ALS, we documented atypical clinical manifestations. Genetic screening for C9orf72 hexanucleotide expansions was performed in 343 patients, and SOD1, TARDBP, and VCP were tested in the subgroup of patients with a family history of ALS. Gray matter and white matter imaging was available in a subgroup of 30 patients. Results Seventy-five (13.6%) patients were identified with ALS-Plus syndrome. We found disorders of ocular motility, cerebellar, extrapyramidal and autonomic functioning. Relative to those without ALS-Plus, cognitive impairment (8.0% vs 2.9%, p=0.029), bulbar-onset (49.3% vs 23.2%, pALS-Plus. Survival was significantly shorter in ALS-Plus (29.66 months vs 42.50 months, p=0.02), regardless of bulbar-onset or mutation status. Imaging revealed significantly greater cerebellar and cerebral disease in ALS-Plus compared to those without ALS-Plus. Conclusions ALS-Plus syndrome is not uncommon, and the presence of these atypical features is consistent with neuropathological observations that ALS is a multisystem disorder. ALS-Plus syndrome is associated with increased risk for poor survival and the presence of a pathogenic mutation. PMID:25086858

Tailoring ultrafine grained and dispersion-strengthened Ti 2 AlC/TiAl ...

Indian Academy of Sciences (India)

In situ Ti 2 AlC/TiAl composite was fabricated by hot-pressing method via the reaction system of Ti 3 AlC 2 and Ti-Al pre-alloyed powders at low temperature of 1150 ∘ C. The composite mainly consisted of TiAl, Ti 3 Al and Ti 2 AlC phases. Fine Ti 2 AlC particles were homogeneously distributed and dispersed in the matrix.

Phase constitution and interface structure of nano-sized Ag-Cu/AlN multilayers: Experiment and ab initio modeling

Energy Technology Data Exchange (ETDEWEB)

Pigozzi, Giancarlo; Janczak-Rusch, Jolanta; Passerone, Daniele; Antonio Pignedoli, Carlo; Patscheider, Joerg; Jeurgens, Lars P. H. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Antusek, Andrej [Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Faculty of Materials Science and Technology, Slovak University of Technology in Bratislava, Paulinska 16, 917 24 Trnava (Slovakia); Parlinska-Wojtan, Magdalena [Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); University of Rzeszow, Institute of Physics, ul. Rejtana 16a, 35-959 Rzeszow (Poland); Bissig, Vinzenz [Kirsten Soldering AG, Hinterbergstrasse 32, CH-6330 Cham (Switzerland)

2012-10-29

Nano-sized Ag-Cu{sub 8nm}/AlN{sub 10nm} multilayers were deposited by reactive DC sputtering on {alpha}-Al{sub 2}O{sub 3}(0001) substrates. Investigation of the phase constitution and interface structure of the multilayers evidences a phase separation of the alloy sublayers into nanosized grains of Ag and Cu. The interfaces between the Ag grains and the quasi-single-crystalline AlN sublayers are semi-coherent, whereas the corresponding Cu/AlN interfaces are incoherent. The orientation relationship between Ag and AlN is constant throughout the entire multilayer stack. These observations are consistent with atomistic models of the interfaces as obtained by ab initio calculations.

Uslûb al-Hiwâr al-Qur’âni bayna al-Muslimîn wa al-Nasâra ‘inda Badî’uzzamân Sa’îd al-Nursi

Directory of Open Access Journals (Sweden)

Sujiat Zubaidi Saleh

2014-11-01

Full Text Available In order to solve some issues, the scholars’ dialogue often generates new ideas as it works to clarify the values of al-Qur’an and to enrich their understanding about it. Therefore, Nursi pointed to unite at present not only with the Muslim community and even with Christians, aside from the differences and disputes over union issues. It is possible to do so when the Muslims and the Christians refrain from their controversies among them. Nursi’s idea does not mean that he does not recognize any differences between them. There are some significant differences between the Christian and the Muslim faith, but those differences should not prevent them from the most important goal to provide new humanitarian look for human life, where God is the axis and the divine will for the moral values of this point. Nursi believes that the current religious relationship marred by erroneous thought as the result of post-modernism worldview. In fact, al-Qur’an recommended a mutual awareness of the communities that shapes them to gain a common goal in God witnesses as the divine values of this modern civilization in opposition to “clash of civilizations”, but this task needs some efforts to discuss on Quranic Dialogue. This dialogue could be undertaken well, as long as it sets out with full love and affection rather than with the fierce conflict and distress. Thus, Nursi introduced new ideas into interfaith dialogue between Muslims and Christians, to build a true civilization based on mutual relations of love.

Assessing behavioural changes in ALS: cross-validation of ALS-specific measures.

Science.gov (United States)

Pinto-Grau, Marta; Costello, Emmet; O'Connor, Sarah; Elamin, Marwa; Burke, Tom; Heverin, Mark; Pender, Niall; Hardiman, Orla

2017-07-01

The Beaumont Behavioural Inventory (BBI) is a behavioural proxy report for the assessment of behavioural changes in ALS. This tool has been validated against the FrSBe, a non-ALS-specific behavioural assessment, and further comparison of the BBI against a disease-specific tool was considered. This study cross-validates the BBI against the ALS-FTD-Q. Sixty ALS patients, 8% also meeting criteria for FTD, were recruited. All patients were evaluated using the BBI and the ALS-FTD-Q, completed by a carer. Correlational analysis was performed to assess construct validity. Precision, sensitivity, specificity, and overall accuracy of the BBI when compared to the ALS-FTD-Q, were obtained. The mean score of the whole sample on the BBI was 11.45 ± 13.06. ALS-FTD patients scored significantly higher than non-demented ALS patients (31.6 ± 14.64, 9.62 ± 11.38; p ALS-FTD-Q was observed (r = 0.807, p ALS-FTD-Q. Good construct validity has been further confirmed when the BBI is compared to an ALS-specific tool. Furthermore, the BBI is a more comprehensive behavioural assessment for ALS, as it measures the whole behavioural spectrum in this condition.

Laughter, crying and sadness in ALS.

Science.gov (United States)

Thakore, Nimish J; Pioro, Erik P

2017-10-01

Pseudobulbar affect (PBA) is prevalent in amyotrophic lateral sclerosis (ALS), but there is limited information on its associations and course. Explore prevalence, associations, course and manifestations of PBA in outpatient cohort of patients with ALS and examine its relationship to depression. Self-reported measures of PBA and depression (Center for Neurologic Study-Lability Scale (CNS-LS) and Patient Health Questionnaire (PHQ-9), respectively) were obtained from consecutive patients with ALS using tablet devices in waiting rooms (Knowledge Program). PBA (CNS-LS ≥13) was seen in 209/735 patients (28.4%). PBA was associated with bulbar onset and dysfunction, upper motor neuron dysfunction, cognitive impairment, depression and lower quality of life. A multivariable model that included lower bulbar and gross motor subscores, female gender, younger age and shorter duration of disease predicted PBA with 74% accuracy. CNS-LS scores increased only slowly with time. Women with PBA reported more crying than men. Crying (but not laughter) correlated with depression, and crying was associated with poorer quality of life. Exploratory factor analysis of pooled questions of CNS-LS and PHQ-9 identified three underlying factors (laughter, crying and depression) loaded on appropriate questions of the respective instruments. This study identifies associations of PBA and additionally finds PBA (especially crying-predominant PBA) more prevalent in women with ALS. Although the two self-report instruments (CNS-LS and PHQ-9) discriminate well between PBA and depression, there is significant overlap between depression and crying in PBA. Studies of PBA should stratify for gender, examine crying and laughter as separate outcomes and adjust for depression. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Plastic deformation of Al13Fe4 particles in Al-Al13Fe4 by high-speed compression

International Nuclear Information System (INIS)

Yoneyama, N.; Mizoguchi, K.; Kumai, S.; Sato, A.; Kiritani, M.

2003-01-01

Spray-formed Al-Fe alloys having undergone high-speed deformation were examined under a high-voltage electron microscope. Two types of specimens were examined; one containing fine Al 13 Fe 4 particles, and the other containing large particles. In the former specimen, deformation is found to proceed in three patterns, depending on specimen thickness and strain rate: (1) without deformation of the Al 13 Fe 4 ; (2) breaking of the Al 13 Fe 4 ; or (3) melting of the Al 13 Fe 4 . Local melting is found to alter some of the Al 13 Fe 4 particles, to impart five-fold symmetry in diffraction or an amorphous structure. In the latter specimen, introduction of glide dislocations enabled us to determine a shear system in the mc102 monoclinic c2/m crystal of Al 13 Fe 4 . On the bases of these observations, the mechanism of high-speed deformation is discussed while taking into account the highly stressed and/or heated states of Al 13 Fe 4 embedded in Al matrix

Synthesis and characterization of pillared bentonite with Al, AL/Fe and impregnated with Pd; Sintese e caracterizacao de bentonitas pilarizadas com Al, AL/Fe e impregnadas com Pd

Energy Technology Data Exchange (ETDEWEB)

Silva, Marcus Vinicius Costa; Pizarro, Alejandro Herrero; Molina, Carmen Belen, E-mail: marcus.ufpa@yahoo.com.br [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Instituto de Tecnologia. Faculdade de Engenharia Quimica; Seccion de Ingenieria Quimica, Facultad de Ciencias, Universidad Autonoma de Madri (Spain)

2017-10-01

In this work, a north american bentonite was pillared with Al and Al/Fe, creating the Al-PILC and Al-Fe-PILC, respectively. Then the Pd was impregnated in the materials, generating Pd-Al-PILC and Pd-Al-Fe-PILC, respectively. The samples were characterized by X-ray diffraction, differential thermal analysis and thermogravimetric and N{sub 2} adsorption at 77 K to determine the specific surface area by BET method (Brunauer - Emmett - Teller). There was an increase in the basal spacing of bentonite from 12.4Å in the original sample to 17.81Å in the Al-Fe-PILC, 17.20Å in Pd-Al-PILC and 17.05Å in the Pd-Al-Fe-PILC. The specific surface area increased from 19.05m{sup 2}/g in the original sample to 173.49m{sup 2}/g in Al-Fe-PILC, 101.31m{sup 2}/g to Pd-Al-PILC and 92m{sup 2}/g in Pd-Al-Fe-PILC. The pillaring process was successful and the synthesized materials have great potential for use as catalysts. (author)

Longitudinal predictors of psychological distress and self-esteem in people with ALS.

Science.gov (United States)

Goldstein, L H; Atkins, L; Landau, S; Brown, R G; Leigh, P N

2006-11-14

To identify predictors of psychological distress (measured by anxiety and depression) and low self-esteem and to determine whether these change over time in people with ALS. We interviewed 50 patients with ALS living with a spouse/partner; further interviews were held at median intervals of 6 and then 5 months. Although carers were interviewed, we report the patients' data. Patients completed measures about their social support and marital relationship; the functional impact of ALS; everyday cognitive, emotional, and behavioral changes; symptoms of anxiety and depression; and self-esteem. The ALS Severity Scale was also completed. From the initial sample of 50, 26 patients were interviewed on all three occasions. At the first interview, negative social support and bulbar impairment were most predictive of psychological distress; pre-illness marital intimacy was the best predictor of patients' self-esteem. Over time, negative social support and pre-illness marital intimacy retained an ability to predict patients' affective state and self-esteem. Social factors are important in determining longer-term psychological well-being in people with ALS who are in the relatively early stages of the disease.

Contenido de metales pesados en pescados comercializados en Iquitos, Nauta y Requena

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Dora García de Sotero

2013-06-01

Full Text Available En este trabajo se presenta la evaluación de la concentración de metales pesados en el músculo de los  pescados colectados en los mercados de las ciudades de Iquitos (Cuenca del Ríos Amazonas; Nauta (Cuenca del Río Marañón y Requena (Cuenca del Río Ucayali en el año 2011. Para la muestra de cada lugar se consideró cinco individuos por cada especie. La metodología empleada para la determinación de Hierro, Cobre, Plomo, Cadmio, Cromo y Cinc fue el método de espectrofotometría de absorción atómica (EEA, y para la determinación de Mercurio se efectuó por la EEA acoplado la Cámara de vapor frio.  De acuerdo a los resultados se observó que en todas las especies estudiadas de las Cuencas de los Ríos Amazonas y Marañón, tanto en creciente como en vaciante, superaron los límites máximos permisibles con respecto a la acumulación de plomo y cromo comparados con los Límites Máximos Permisibles reportados por las Normas Internacionales. Para las especies de la Cuenca del Río Ucayali, en creciente algunas especies (lisa, boquichico y paco pasaron el límite máximo permisible con respecto a la acumulación de cromo; pero en vaciante todas las especies pasaron ese límite. Con respecto al mercurio, ninguna de las especies en estudio, de las tres Cuencas pasaron el límite máximo permisible cuando fueron comparados con los valores reportados por las Normas Internacionales.

Contenido de metales pesados en pescados comercializados en Iquitos, Nauta y Requena

Directory of Open Access Journals (Sweden)

Dora García de Sotero

2013-06-01

Full Text Available En este trabajo se presenta la evaluación de la concentración de metales pesados en el músculo de los pescados colectados en los mercados de las ciudades de Iquitos (Cuenca del Ríos Amazonas; Nauta (Cuenca del Río Marañón y Requena (Cuenca del Río Ucayali en el año 2011. Para la muestra de cada lugar se consideró cinco individuos por cada especie. La metodología empleada para la determinación de Hierro, Cobre, Plomo, Cadmio, Cromo y Cinc fue el método de espectrofotometría de absorción atómica (EEA, y para la determinación de Mercurio se efectuó por la EEA acoplado la Cámara de vapor frio.  De acuerdo a los resultados se observó que, en todas las especies estudiadas de las Cuencas de los Ríos Amazonas y Marañón, tanto en creciente como en vaciante, superaron los límites máximos permisibles con respecto a la acumulación de plomo y cromo comparados con los Límites Máximos Permisibles reportados por las Normas Internacionales. Para las especies de la Cuenca del Río Ucayali, en creciente algunas especies (lisa, boquichico y paco pasaron el límite máximo permisible con respecto a la acumulación de cromo; pero en vaciante todas las especies pasaron ese límite. Con respecto al mercurio, ninguna de las especies en estudio, de las tres Cuencas pasaron el límite máximo permisible cuando fueron comparados con los valores reportados por las Normas Internacionales.

Reducing Mg acceptor activation-energy in Al(0.83)Ga(0.17)N disorder alloy substituted by nanoscale (AlN)₅/(GaN)₁ superlattice using Mg(Ga) δ-doping: Mg local-structure effect.

Science.gov (United States)

Zhong, Hong-xia; Shi, Jun-jie; Zhang, Min; Jiang, Xin-he; Huang, Pu; Ding, Yi-min

2014-10-23

Improving p-type doping efficiency in Al-rich AlGaN alloys is a worldwide problem for the realization of AlGaN-based deep ultraviolet optoelectronic devices. In order to solve this problem, we calculate Mg acceptor activation energy and investigate its relationship with Mg local structure in nanoscale (AlN)5/(GaN)1 superlattice (SL), a substitution for Al(0.83)Ga(0.17)N disorder alloy, using first-principles calculations. A universal picture to reduce acceptor activation energy in wide-gap semiconductors is given for the first time. By reducing the volume of the acceptor local structure slightly, its activation energy can be decreased remarkably. Our results show that Mg acceptor activation energy can be reduced significantly from 0.44 eV in Al(0.83)Ga(0.17)N disorder alloy to 0.26 eV, very close to the Mg acceptor activation energy in GaN, and a high hole concentration in the order of 10(19) cm(-3) can be obtained in (AlN)5/(GaN)1 SL by Mg(Ga) δ-doping owing to GaN-monolayer modulation. We thus open up a new way to reduce Mg acceptor activation energy and increase hole concentration in Al-rich AlGaN.

Reducing Mg Acceptor Activation-Energy in Al0.83Ga0.17N Disorder Alloy Substituted by Nanoscale (AlN)5/(GaN)1 Superlattice Using MgGa δ-Doping: Mg Local-Structure Effect

Science.gov (United States)

Zhong, Hong-Xia; Shi, Jun-Jie; Zhang, Min; Jiang, Xin-He; Huang, Pu; Ding, Yi-Min

2014-10-01

Improving p-type doping efficiency in Al-rich AlGaN alloys is a worldwide problem for the realization of AlGaN-based deep ultraviolet optoelectronic devices. In order to solve this problem, we calculate Mg acceptor activation energy and investigate its relationship with Mg local structure in nanoscale (AlN)5/(GaN)1 superlattice (SL), a substitution for Al0.83Ga0.17N disorder alloy, using first-principles calculations. A universal picture to reduce acceptor activation energy in wide-gap semiconductors is given for the first time. By reducing the volume of the acceptor local structure slightly, its activation energy can be decreased remarkably. Our results show that Mg acceptor activation energy can be reduced significantly from 0.44 eV in Al0.83Ga0.17N disorder alloy to 0.26 eV, very close to the Mg acceptor activation energy in GaN, and a high hole concentration in the order of 1019 cm-3 can be obtained in (AlN)5/(GaN)1 SL by MgGa δ-doping owing to GaN-monolayer modulation. We thus open up a new way to reduce Mg acceptor activation energy and increase hole concentration in Al-rich AlGaN.

Fórmulas de Insecticidas y Fungicidas.

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Universidad Nacional de Colombia Facultad de Ciencias Agrarias

1942-08-01

Full Text Available Un gran número de casas americanas y europeas preparan insecticidas de gran eficacia y de relativa baratura. El uso de estos preparados se puede, frecuentemente, recomendar como de mayor eficacia que los compuestos en las fincas, pero por la dificultad de conseguirlos en Guatemala, damos a continuación algunas fórmulas para preparar los de uso más corriente y útil. Prácticamente, todos los venenos estomacales de uso corriente son compuestos arsenicales como el verde de París, el arseniato de plomo y el arseniato de calcio. La sustancia por preferir depende del costo, de la naturaleza de la planta y de la clase de insecto. La dificultad con todos esos compuestos es el peligro de quemar el follaje. El verde de París es el que en mayor grado tiene este inconveniente que se minora, en parte, agregando una lechada de cal a la dilución del veneno. La lechada de cal debe colarse previamente para evitar obstrucciones de la boquilla del pulverizador. El Arseniato de plomo, que generalmente se prefiere al verde de París, se consigue en pasta o en polvo. La dilución se hace con una libra de polvo o dos de la pasta para 50 galones de agua. Una lata de gasolina cuya capacidad es de 5 galones constituye un recipiente a propósito para medir las cantidades de agua. El arscniato de calcio en pasta, debe mezclarse en la proporción de 2 libras para 50 galones de agua; del polvo, sólo se necesitan 3/1 de libra para los mismos 50 galones de agua. Con cualquiera de los ingredientes citados se prepara la dilución insecticida usando primero una pequeña cantidad de agua agitando enérgicamente para incorporar íntimamente el polvo o la pasta al agua y luego agregando el resto de agua. Conviene agregar algo de jabón a la dilución para que humedezca y se adhiera mejor a las hojas. Cualquier jabón barato de lavar, puede servir para este caso en la cantidad de una a tres libras para 50 galones de agua.

Electrodeposition of Al from a 1-butylpyrrolidine-AlCl3 ionic liquid

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Giridhar Pulletikurthi

2015-12-01

Full Text Available The addition of 1-butylpyrrolidine to AlCl3 results in the formation of an electrolyte that is suited to Al deposition. The feasibility of electrodepositing Al from the synthesized electrolyte was investigated. Several compositions of AlCl3 and 1-butylpyrrolidine were prepared for this purpose. These mixtures show a different phase behavior at various compositions of AlCl3 and 1-butylpyrrolidine. IR, Raman and NMR spectroscopy were employed to characterize the synthesized liquids. Among the prepared compositions, 1:1.2 mol ratio of 1-butylpyrrolidine:AlCl3 and the upper phase of 1:1.3 mol ratio of 1-butylpyrrolidine:AlCl3 were found to be suitable for Al electrodeposition at room temperature (RT. Uniform and thick (~µm thick layers of Al were obtained on copper at RT. Al deposition occured from the cationic species of AlCl3−xLy+ (where x≤2, y=1–2, and L=1-butylpyrrolidine in this electrolyte. This behavior is contrary to the well investigated classic AlCl3 based ionic liquids, where the deposition of Al occurs mainly from anionic Al2Cl7− ions.

Orientation of Al3Ti platelets in Al-Al3Ti functionally graded material manufactured by centrifugal method

International Nuclear Information System (INIS)

Watanabe, Y.; Fukui, Y.

1997-01-01

Al-Al 3 Ti functionally graded materials (FGMs) were manufactured by the centrifugal method with a commercial ingot of Al-5 mass% Ti master alloy. The alloy was melted at a liquid/solid coexisting temperature, at which Al 3 Ti remains as a solid, and then it was cast into a thick-walled ring. It was found that the Al-Al 3 Ti functionally graded material can be successfully fabricated by the centrifugal method. It was also found that the volume fraction of the Al 3 Ti can be increased by repetition of the centrifugal method. Since the shape of Al 3 Ti particles in a commercial alloy ingot is that of a platelet, the Al 3 Ti particles are arranged with their platelet planes nearly perpendicular to the radial direction. The orientation effects become stronger when the G number becomes larger. Although the final centrifugal casting was conducted under a very large centrifugal force for the specimen cast three times, the orientation effects were weaker than those in the specimen cast one time. From these observations, it is concluded that the origin of orientation of Al 3 Ti platelets can be attributed to the angular velocity gradient of the melt along the radial direction produced by the difference in the viscosity. (orig.)

In situ synthesis of Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite by vacuum sintering mechanically alloyed TiAl powder coated with CNTs

Energy Technology Data Exchange (ETDEWEB)

Wang, Jian [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Zhao, Naiqin, E-mail: nqzhao@tju.edu.cn [State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin (China); Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Nash, Philip [Thermal Processing Technology Center, Illinois Institute of Technology, IL (United States); Liu, Enzuo; He, Chunnian; Shi, Chunsheng; Li, Jiajun [Department of Materials Science and Engineering of Tianjin University, Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

2013-11-25

Highlights: •Using zwitterionic surfactant to enhance the dispersion of the CNTs on the powder surface. •CNTs as carbon source decreased the formation temperature of Ti{sub 2}AlC. •Al{sub 2}O{sub 3} was generated in situ from the oxygen atoms introduced in the drying procedure. •Nanosized Ti{sub 3}Al was precipitated at 1250 °C and distribute in the TiAl matrix homogeneously. •Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composite was synthesized in situ by sintering pre-alloy Ti–Al coated with CNTs. -- Abstract: Bulk Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were in situ synthesized by vacuum sintering mechanically alloyed Ti–50 at.% Al powders coated with carbon nanotubes (CNTs). The pre-alloyed Ti–50 at.% Al powder was obtained by ball milling Ti and Al powders. The multi-walled carbon nanotubes as the carbon resource were covered on the surface of the pre-alloyed powders by immersing them into a water solution containing the CNTs. A zwitterionic surfactant was used to enhance the dispersion of the CNTs on the powder surface. The samples were cold pressed and sintered in vacuum at temperatures from 950 to 1250 °C, respectively. The results show that the reaction of forming Ti{sub 2}AlC can be achieved below 950 °C, which is 150 °C lower than in the Ti–Al–TiC system and 250 °C lower than for the Ti–Al–C system due to the addition of CNTs. Additionally, the reinforcement of Al{sub 2}O{sub 3} particles was introduced in situ in Ti{sub 2}AlC/TiAl by the drying process and subsequent sintering of the composite powders. Dense Ti{sub 2}AlC–Al{sub 2}O{sub 3}/TiAl composites were obtained by sintering at 1250 °C and exhibited a homogeneous distribution of Ti{sub 2}AlC, Al{sub 2}O{sub 3} and precipitated Ti{sub 3}Al particles and a resulting high hardness.

27Al NMR studies of NpPd5Al2

International Nuclear Information System (INIS)

Chudo, H.; Sakai, H.; Tokunaga, Y.; Kambe, S.; Aoki, D.; Homma, Y.; Shiokawa, Y.; Haga, Y.; Ikeda, S.; Matsuda, T.D.; Onuki, Y.; Yasuoka, H.

2009-01-01

We present 27 Al NMR studies for a single crystal of the Np-based superconductor NpPd 5 Al 2 (T c =4.9K). We have observed a five-line 27 Al NMR spectrum with a center line and four satellite lines separated by first-order nuclear quadrupole splittings. The Knight shift clearly drops below T c . The temperature dependence of the 27 Al nuclear spin-lattice relaxation rate shows no coherence peak below T c , indicating that NpPd 5 Al 2 is an unconventional superconductor with an anisotropic gap. The analysis of the present NMR data provides evidence for strong-coupling d-wave superconductivity in NpPd 5 Al 2 .

Magnetic tunnel junctions with AlN and AlNxOy barriers

International Nuclear Information System (INIS)

Schwickert, M. M.; Childress, J. R.; Fontana, R. E.; Kellock, A. J.; Rice, P. M.; Ho, M. K.; Thompson, T. J.; Gurney, B. A.

2001-01-01

Nonoxide tunnel barriers such as AlN are of interest for magnetic tunnel junctions to avoid the oxidation of the magnetic electrodes. We have investigated the fabrication and properties of thin AlN-based barriers for use in low resistance magnetic tunnel junctions. Electronic, magnetic and structural data of tunnel valves of the form Ta (100 Aa)/PtMn (300 Aa)/CoFe 20 (20 Aa - 25 Aa)/barrier/CoFe 20 (10 - 20 Aa)/NiFe 16 (35 - 40 Aa)/Ta (100 Aa) are presented, where the barrier consists of AlN, AlN x O y or AlN/AlO x with total thicknesses between 8 and 15 Aa. The tunnel junctions were sputter deposited and then lithographically patterned down to 2 x 2μm 2 devices. AlN was deposited by reactive sputtering from an Al target with 20% - 35% N 2 in the Ar sputter gas at room temperature, resulting in stoichiometric growth of AlN x (x=0.50±0.05), as determined by RBS. TEM analysis shows that the as-deposited AlN barrier is crystalline. For AlN barriers and AlN followed by natural O 2 oxidation, we obtain tunnel magnetoresistance >10% with specific junction resistance R j down to 60Ωμm 2 . [copyright] 2001 American Institute of Physics

Size Class Dependent Relationships between Temperature and Phytoplankton Photosynthesis-Irradiance Parameters in the Atlantic Ocean

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Alex Robinson

2018-01-01

Full Text Available Over the past decade, a number of methods have been developed to estimate size-class primary production from either in situ phytoplankton pigment data or remotely-sensed data. In this context, the first objective of this study was to compare two methods of estimating size class specific (micro-, nano-, and pico-phytoplankton photosynthesis-irradiance (PE parameters from pigment data. The second objective was to analyse the relationship between environmental variables (temperature, nitrate and PAR and PE parameters in the different size-classes. A large dataset was used of simultaneous measurements of the PE parameters (n = 1,260 and phytoplankton pigment markers (n = 2,326, from 3 different institutes. There were no significant differences in mean PE parameters of the different size classes between the chemotaxonomic method of Uitz et al. (2008 and the pigment markers and carbon-to-Chl a ratios method of Sathyendranath et al. (2009. For both methods, mean maximum photosynthetic rates (PmB for micro-phytoplankton were significantly lower than those for pico-phytoplankton and nano-phytoplankton. The mean light limited slope (αB for nano-phytoplankton were significantly higher than for the other size taxa. For micro-phytoplankton dominated samples identified using the Sathyendranath et al. (2009 method, both PmB and αB exhibited a significant, positive linear relationship with temperature, whereas for pico-phytoplankton the correlation with temperature was negative. Nano-phytoplankton dominated samples showed a positive correlation between PmB and temperature, whereas for αB and the light saturation parameter (Ek the correlations were not significant. For the Uitz et al. (2008 method, only micro-phytoplankton PmB, pico-phytoplankton αB, nano- and pico-phytoplankton Ek exhibited significant relationships with temperature. The temperature ranges occupied by the size classes derived using these methods differed. The Uitz et al. (2008 method

A study of the Al-rich part of the Al-Re alloy system

International Nuclear Information System (INIS)

Balanetskyy, S.; Grushko, B.

2008-01-01

The Al-rich part of the Al-Re phase diagram was reinvestigated by scanning and transmission electron microscopy, powder X-ray diffraction and differential thermal analysis. The earlier reported Al 12 Re, Al 6 Re, and Al 11 Re 4 phases were confirmed. Close to the Al 4 Re composition a high-temperature h-Al 4 Re and a low-temperature l-Al 4 Re phase were found to be formed at slightly different compositions. Both exhibited compositional ranges. A new phase was revealed close to the Al 3 Re composition. The Al 11 Re 4 phase is formed congruently at 1650 deg. C, Al 3 Re peritectically at 1610 deg. C, h-Al 4 Re peritectically at 1410 deg. C, l-Al 4 Re peritectically at ∼1000 deg. C, Al 6 Re peritectically at 813 deg. C and Al 12 Re peritectically at 746 deg. C. Finally, the Al 12 Re-(Al) eutectic is formed at 658 deg. C. The Al 3 Re and h-Al 4 Re are decomposed by eutectoid reactions at ∼946 and 833 deg., respectively. The structure of the h-Al 4 Re phase has not yet been clarified, but it is distinctly different from the Al 4 W phase suggested earlier. The structure of l-Al 4 Re was confirmed. The Al 3 Re phase was found to have a monoclinic structure with a = 0.5180(4) nm, b = 3.97641(9) nm, c = 0.4955(3) nm and β = 99.55(7) o

Blood Test: Lead (For Parents)

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... Staying Safe Videos for Educators Search English Español Blood Test: Lead KidsHealth / For Parents / Blood Test: Lead What's ... español Análisis de sangre: plomo What Is a Blood Test? A blood test is when a sample of ...

The relationships between academic self-efficacy, intrinsic motivation, and perceived competence

OpenAIRE

Buch, Robert; Säfvenbom, Reidar; Boe, Ole

2015-01-01

© 2015 Buch et al. This is an open access article. This study investigated the moderating role of intrinsic motivation for military studies on the relationship between academic self-efficacy and change in perceived military competence. We present two concurrent hypotheses based on theoretical interaction effects of intrinsic motivation. Data from 245 cadets from three military academies revealed a positive relationship between self-efficacy and an increase in perceived military competence ...

INTER-RELATIONSHIP BETWEEN DRUG USE, ANOMIE, ALIENATION AND AUTTHORITARIANISM AMONGST UNIVERSITY STUDENTS

Science.gov (United States)

Agarwal, Ravi K.; Varma, Vijoy K.; Dang, Ravinder

1980-01-01

SUMMARY The degree of addictive substance usage score and three personality variables, namely, authoritarianism, alienation, and anomie were measured in 197 university students through a self-administered questionnaire. WHO's Youth Survey Questionnaire for drag use, Varma et al.'s scale of Authoritarianism, Srole's scale of Anomie, and Pearlin's scale of Alienation, were used. A study of the relationship between the co-variables was studied and is discussed. PMID:22058449

Abu al-Layth al-Libi

Science.gov (United States)

2015-02-01

success. As an Arab participant acknowledged very early on, “the situation was really harsh. All the brothers were tired,” as they lacked food and... glorious battles that occurred during the early Islamic period.133 He stressed the importance of the battlefield as the path to achieve honor and dignity...diaspora in Waziristan. In the words of Walid Othmani, a French jihadi trained by al-Qa`ida in Waziristan in 2008, “[Al-Libi] was someone well-known and

SAP-like ultrafine-grained Al composites dispersion strengthened with nanometric AlN

International Nuclear Information System (INIS)

Balog, M.; Krizik, P.; Yan, M.; Simancik, F.; Schaffer, G.B.; Qian, M.

2013-01-01

This paper reports the development of novel Sinter-Aluminum-Pulver (SAP)-like Al–AlN nanocomposites via replacing the native Al 2 O 3 thin films on fine Al powder with a large volume fraction of in situ formed nanometric AlN dispersoids. Fine gas-atomized Al powder (d 50 =1.3 µm) compacts were first partially nitrided at 590 °C in flowing nitrogen, controlled by a small addition of Sn (0.3–0.4 wt%), and subsequently consolidated by hot direct extrusion. The resulting Al–AlN composites consisted of submicrometric Al grains reinforced with nanometric AlN dispersoids together with some nanometric Al 2 O 3 dispersoids. An Al–13 vol% AlN nanocomposite fabricated this way achieved exceptional ultimate tensile strength of 227 MPa, yield strength of 195 MPa and Young's modulus of 66 GPa at 300 °C, superior to typical SAP materials and coarse grained Al–AlN composites. In addition, the Al–13 vol% AlN nanocomposite exhibited good thermal stability up to 500 °C. The strengthening mechanism is discussed

Analisis Kecenderungan Manhaj Akidah Shaykh Shams al-Din al-Sumatera’i

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MOHD HAIDHAR KAMARZAMAN

2016-12-01

Full Text Available Shaykh Shams al-Din al-Sumatera'i is a very great and respected scholar during 16th and 17th century of Acheh. His knowledge in various fields recognized by local and international scholars. He had been a Qadi Malik al-’Adil, a religious leader, who became a referred by communities and country during the reign of the three Sultans of Aceh. He has authored nearly 40 pieces of books related to the theology and sufism. This study focuses on the methods used by Shaykh Shams al-Din al-Sumatera'i in his theological writings. This study found that Shaykh Shams al-Din al-Sumatera'i had used six methods in the such writings.

Ultrasonic spot welding of Al/Mg/Al tri-layered clad sheets

International Nuclear Information System (INIS)

Macwan, A.; Patel, V.K.; Jiang, X.Q.; Li, C.; Bhole, S.D.; Chen, D.L.

2014-01-01

Highlights: • The optimal welding condition is achieved at 100 J and 0.1 s. • Failure load first increases and then decreases with increasing welding energy. • The highest failure load after welding is close to that of the clad sheets. • At low energy levels failure occurs in the mode of interfacial failure. • At high energy levels failure takes place at the edge of nugget region. - Abstract: Solid-state ultrasonic spot welding (USW) was used to join Al/Mg/Al tri-layered clad sheets, aiming at exploring weldability and identifying failure mode in relation to the welding energy. It was observed that the application of a low welding energy of 100 J was able to achieve the optimal welding condition during USW at a very short welding time of 0.1 s for the tri-layered clad sheets. The optimal lap shear failure load obtained was equivalent to that of the as-received Al/Mg/Al tri-layered clad sheets. With increasing welding energy, the lap shear failure load initially increased and then decreased after reaching a maximum value. At a welding energy of 25 J, failure occurred in the mode of interfacial failure along the center Al/Al weld interface due to insufficient bonding. At a welding energy of 50 J, 75 J and 100 J, failure was also characterized by the interfacial failure mode, but it occurred along the Al/Mg clad interface rather than the center Al/Al weld interface, suggesting stronger bonding of the Al/Al weld interface than that of the Al/Mg clad interface. The overall weld strength of the Al/Mg/Al tri-layered clad sheets was thus governed by the Al/Mg clad interface strength. At a welding energy of 125 J and 150 J, thinning of weld nugget and extensive deformation at the edge of welding tip caused failure at the edge of nugget region, leading to a lower lap shear failure load

L-J phase in a Cu2.2Mn0.8Al alloy

Science.gov (United States)

Jeng, S. C.; Liu, T. F.

1995-06-01

A new type of precipitate (designated L-J phase) with two variants was observed within the (DO3 + L21) matrix in a Cu2.2Mn0.8Al alloy. Transmission electron microscopy examinations indicated that the L-J phase has an orthorhombic structure with lattice parameters a = 0.413 nm, b = 0.254 nm and c = 0.728 nm. The orientation relationship between the L-J phase and the matrix is (100)L-J//(011) m , (010)L-J//(111) m and (001)L-J//(211) m . The rotation axis and rotation angle between two variants of the L-J phase are [021] and 90 deg. The L-J phase has never been observed in various Cu-Al, Cu-Mn, and Cu-Al-Mn alloy systems before.

New Insights into c-Ret Signalling Pathway in the Enteric Nervous System and Its Relationship with ALS

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M. J. Luesma

2014-01-01

Full Text Available The receptor tyrosine kinase Ret (c-Ret transduces the glial cell line-derived neurotrophic factor (GDNF signal, one of the neurotrophic factors related to the degeneration process or the regeneration activity of motor neurons in amyotrophic lateral sclerosis (ALS. The phosphorylation of several tyrosine residues of c-Ret seems to be altered in ALS. c-Ret is expressed in motor neurons and in the enteric nervous system (ENS during the embryonic period. The characteristics of the ENS allow using it as model for central nervous system (CNS study and being potentially useful for the research of human neurological diseases such as ALS. The aim of the present study was to investigate the cellular localization and quantitative evaluation of marker c-Ret in the adult human gut. To assess the nature of c-Ret positive cells, we performed colocalization with specific markers of cells that typically are located in the enteric ganglia. The colocalization of PGP9.5 and c-Ret was preferentially intense in enteric neurons with oval morphology and mostly peripherally localized in the ganglion, so we concluded that the c-Ret receptor is expressed by a specific subtype of enteric neurons in the mature human ENS of the gut. The functional significance of these c-Ret positive neurons is discussed.

New insights into c-Ret signalling pathway in the enteric nervous system and its relationship with ALS.

Science.gov (United States)

Luesma, M J; Cantarero, I; Álvarez-Dotu, J M; Santander, S; Junquera, C

2014-01-01

The receptor tyrosine kinase Ret (c-Ret) transduces the glial cell line-derived neurotrophic factor (GDNF) signal, one of the neurotrophic factors related to the degeneration process or the regeneration activity of motor neurons in amyotrophic lateral sclerosis (ALS). The phosphorylation of several tyrosine residues of c-Ret seems to be altered in ALS. c-Ret is expressed in motor neurons and in the enteric nervous system (ENS) during the embryonic period. The characteristics of the ENS allow using it as model for central nervous system (CNS) study and being potentially useful for the research of human neurological diseases such as ALS. The aim of the present study was to investigate the cellular localization and quantitative evaluation of marker c-Ret in the adult human gut. To assess the nature of c-Ret positive cells, we performed colocalization with specific markers of cells that typically are located in the enteric ganglia. The colocalization of PGP9.5 and c-Ret was preferentially intense in enteric neurons with oval morphology and mostly peripherally localized in the ganglion, so we concluded that the c-Ret receptor is expressed by a specific subtype of enteric neurons in the mature human ENS of the gut. The functional significance of these c-Ret positive neurons is discussed.

Role of microstructure in the mean stress dependence of fatigue strength in Ti-6Al-4V alloy

Energy Technology Data Exchange (ETDEWEB)

Ivanova, S.G.; Cohen, F.S.; Biederman, R.R.; Sisson, R.D. Jr.

1999-07-01

The high cycle fatigue properties of Ti-6Al-4V alloy with six different microstructure/texture combinations were investigated. Only materials with lamellar and fine bimodal microstructures exhibited linear Goodman relationship on the constant fatigue life diagram. Materials with coarse bimodal and equiaxed microstructures had anomalous mean stress dependency, with HCF strength at intermediate mean stresses being significantly lower than predicted by Goodman relationship, regardless of whether material was forged or cross-rolled. The role of microstructure in mean stress sensitivity behavior of Ti-6Al-4V is studied. Cyclic strain tests were conducted for all microstructures, and the results of strain-controlled and stress-controlled cyclic tests are compared and discussed.

The relationship between Business Strategy, IT Strategy and Alignment Capability

NARCIS (Netherlands)

Drs. A.J.G. Silvius

2009-01-01

Aligning business and IT strategy is a prominent area of concern. Organizations that successfully align their business strategy and their IT strategy, outperform their non-aligned peers (Chan et al., 1997). This chapter explores the relationship between business strategy, IT strategy and alignment

KITAB AL-SANĪ AL-MAṬĀLIB: INTERKONEKSI NAHWU DAN TASAWUF

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Zakiyah Zakiyah

2012-12-01

Tulisan ini mereview buku yang berjudul al-Sanī al-Maṭālib yang ditulis oleh Kiai Nur Iman Mlangi Yogyakarta. Buku ini ditulis dalam bahasa Arab yang me­ngandung interkoneksi antara ilmu Nahwu (tata bahasa Arab dengan mis­tisis­me. Buku ini sangat menarik karena kenyataan bahwa kedua pengetahuan tersebut memiliki aturan sendiri-sendiri. Selain itu, sangat sedikit penulis yang menulis dengan gaya seperti itu. Salah satunya adalah Syaikh Abdul Qadir bin Ahmad al-Kuhany dengan karyanya yang berjudul Manniyat al-Fāqir al-Munjarid wa Sayrat al-Murīd al-Mutafarrid. Buku al-Saniy al-Muthalib diduga telah ditulis pada akhir abad ke-18 atau awal abad ke-19, menurut periode kehidupan Kiai Nur Iman yaitu sekitar pertengahan abad ke-18. Aturan Nahwu dalam buku ini dijelaskan secara teosofi yang dimulai dengan penjelasan mengenai tauhid (keesaan Tuhan sebagai kajian dasar bagi orang Islam, yang diikuti dengan makna dari masing-masing aturan bahasa Arab dalam aspek mistiknya.

Thermophysical Properties of Cold and Vacuum Plasma Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings. Part 1; Electrical and Thermal Conductivity, Thermal Diffusivity, and Total Hemispherical Emissivity

Science.gov (United States)

Raj, S. V.

2017-01-01

This two-part paper reports the thermophysical properties of several cold and vacuum plasma sprayed monolithic Cu and Ni-based alloy coatings. Part I presents the electrical and thermal conductivity, thermal diffusivity, and total hemispherical emissivity data while Part II reports the specific heat capacity data for these coatings. Metallic copper alloys, stoichiometric NiAl and NiCrAlY coatings were fabricated by either the cold sprayed or the vacuum plasma spray deposition processes for thermal property measurements between 77 and 1223 K. The temperature dependencies of the thermal conductivities, thermal diffusivities, electrical conductivities and total hemispherical emissivities of these cold and vacuum sprayed monolithic coatings are reported in this paper. The electrical and thermal conductivity data correlate reasonably well for Cu-8%Cr-1%Al, Cu-23%Cr-5%Al and NiAl in accordance with the Wiedemann-Franz (WF) law although a better fit is obtained using the Smith-Palmer relationship. The Lorentz numbers determined from the WF law are close to the theoretical value.

Rekonstruksi Konsep Ijtihad: Studi Pemikiran Ben’umar tentang al-Ijtihad fi al-Waqi’

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Duski Ibrahim

2015-10-01

Full Text Available This paper is the result of a research that evaluating the reconstruction the concept of ijtihad, by discuss the idea of al-Ijtihad Ben'umar fi al-waqi’. This paper concludes that Al-Ijtihad fi al-waqi’ is actually a form of collective ijtihad (al ijtihad al-jama'i, by gathering the experts of shari'ah law (fuqaha` ash-shar'i and experts Researchers and scientists (khubara` al-'ashr. Because experts know the nash purposes, while researchers and scientists (al-khubara` know the reality (al-waqi’, the effects in the future (ma'alat = future effect and challenges (tahaddiyat. The idea of formulating the concept of al-ijtihad fi al-waqi’ emerged based on a premise that ijtihad is a creation of experts to implement Islamic law in society. Therefore, the concept of ijtihad experienced a significant development, start from using the nash from the language aspects, continue to the using of logic. At the moment when the situation people are increasingly develop, then the creation of ijtihad become a necessary to developed, for example in the form of al-ijtihad fi al-waqi’ . About the source of the formation of the concept of al -ijtihad fi al-waqi’ comes from theory about the functions of nash, al-manath theory in Islamic law, and supported by the theory of al-mashlalah al-mursalah.

Effect of the thermal evaporation rate of Al cathodes on organic light emitting diodes

International Nuclear Information System (INIS)

Shin, Hee Young; Suh, Min Chul

2014-01-01

Graphical abstract: - Highlights: • The TOF-SIMS analysis to investigate cathode diffusion during evaporation process. • Performance change of OLEDs prepared with different evaporation rate of Al cathode. • Change of electron transport behavior during thermal evaporation process. - Abstract: The relationship between the thermal evaporation rate of Al cathodes and the device performance of organic light-emitting diodes (OLEDs) was investigated to clarify the source of leakage current. Time-of-flight secondary ion mass spectrometry was applied to identify the diffusion of Li and Al fragments into the underlying organic layer during the thermal evaporation process. We prepared various OLEDs by varying the evaporation rates of the Al cathode to investigate different device performance. Interestingly, the leakage current level decreased when the evaporation rate reached ∼25 Å/s. In contrast, the best efficiency and operational lifetime was obtained when the evaporation rate was 5 Å/s

Dynamic tensile response of alumina-Al composites

International Nuclear Information System (INIS)

Atisivan, R.; Bandyopadhyay, A.; Gupta, Y. M.

2002-01-01

Plate impact experiments were carried out to examine the high strain-rate tensile response of alumina-aluminum (Al) composites with tailored microstructures. A novel processing technique was used to fabricate interpenetrating phase alumina-aluminum composites with controlled microstructures. Fused deposition modeling (FDM), a commercially available rapid prototyping technique, was used to produce the controlled porosity mullite ceramic preforms. Alumina-Al composites were then processed via reactive metal infiltration of porous mullite ceramics. With this approach, both the micro as well as the macro structures can be designed via computer aided design (CAD) to tailor the properties of the composites. Two sets of dynamic tensile experiments were performed. In the first, the metal content was varied between 23 and 39 wt. percent. In the second, the microstructure was varied while holding the metal content nearly constant. Samples with higher metal content, as expected, displayed better spall resistance. For a given metal content, samples with finer metal diameter showed better spall resistance. Relationship of the microstructural parameters on the dynamic tensile response of the structured composites is discussed here

Relationship between the catalytic activity of Pt/alumina and the relaxation process of the photoexcited electrons

International Nuclear Information System (INIS)

Ito, Junji; Hanaki, Yasunari; Shen, Qing; Toyoda, Taro

2012-01-01

Highlights: ► We determined the decay time of photoexcited electrons of Pt/Al 2 O 3 . ► Faster decay of excited electrons in Pt/Al 2 O 3 leads to its faster oxidation rate. ► Decreasing excited electron lifetime in Pt/Al 2 O 3 may decrease Pt consumption in catalytic convertors. - Abstract: In order to decrease the consumption of precious metals used in the catalytic converters used in automobiles, we studied the relationship between the catalytic activity of Pt/alumina (Pt/Al 2 O 3 ) and the relaxation process of photoexcited electrons. Firstly, we studied the relationship between the size of the Pt particles in Pt/Al 2 O 3 and catalytic performance. Secondly, the relationship between the size of the Pt particles in Pt/Al 2 O 3 and the decay time of the excited electrons was studied using an improved transient grating (TG) technique. The results showed that faster decay of the excited electrons leads to greater oxidation rates. The decay time obtained with the improved TG technique gives an indication of the time that the exited electrons take to return to the ground state. According to studies utilizing FT-IR, one of the processes necessary for quickly generating CO 2 with Pt is that the electron in the Pt-O bond moves to the Pt side and that the Pt + becomes Pt metal. Thus, the decay time obtained with the improved TG technique corresponds to the process whereby Pt + returns to Pt metal. Thus, we found that the consumption of precious metals can be reduced by increasing the speed of the decay of the excited electrons.

Decision-making among patients and their family in ALS care: a review.

Science.gov (United States)

Foley, Geraldine; Hynes, Geralyn

2018-05-01

Practice guidelines in ALS care emphasise the role of the patient and their family in the decision-making process. We aimed to examine the ALS patient/family relationship in the decision-making process and to ascertain how patients and their family can shape one another's decisions pertaining to care. We conducted a review of peer-reviewed empirical research, published in full and in English between January 2007 and January 2017, relating to care decision-making among ALS patients and their family. Database sources included: Medline; CINAHL; AMED; PsycINFO; PsycARTICLES; and Social Sciences Full Text. A narrative synthesis was undertaken. Forty-seven studies from the empirical literature were extracted. The family viewpoint was captured primarily from family members with direct care-giving duties. Patients' cognitive status was not routinely assessed. The findings revealed that the decision-making process in ALS care can be contoured by patients' and family caregivers' perceived responsibilities to one another and to the wider family. Greater attention to family member roles beyond the primary caregiver role is needed. Strategies that integrate cognitively-impaired patients into the family decision-making process require investigation. Identification of the domains in which ALS patients and their family members support one another in the decision-making process could facilitate the development of patient/family decision-making tools in ALS care.

Inter-relationship between scaling exponents for describing self-similar river networks

Science.gov (United States)

Yang, Soohyun; Paik, Kyungrock

2015-04-01

Natural river networks show well-known self-similar characteristics. Such characteristics are represented by various power-law relationships, e.g., between upstream length and drainage area (exponent h) (Hack, 1957), and in the exceedance probability distribution of upstream area (exponent ɛ) (Rodriguez-Iturbe et al., 1992). It is empirically revealed that these power-law exponents are within narrow ranges. Power-law is also found in the relationship between drainage density (the total stream length divided by the total basin area) and specified source area (the minimum drainage area to form a stream head) (exponent η) (Moussa and Bocquillon, 1996). Considering that above three scaling relationships all refer to fundamental measures of 'length' and 'area' of a given drainage basin, it is natural to hypothesize plausible inter-relationship between these three scaling exponents. Indeed, Rigon et al. (1996) demonstrated the relationship between ɛ and h. In this study, we expand this to a more general ɛ-η-h relationship. We approach ɛ-η relationship in an analytical manner while η-h relationship is demonstrated for six study basins in Korea. Detailed analysis and implications will be presented. References Hack, J. T. (1957). Studies of longitudinal river profiles in Virginia and Maryland. US, Geological Survey Professional Paper, 294. Moussa, R., & Bocquillon, C. (1996). Fractal analyses of tree-like channel networks from digital elevation model data. Journal of Hydrology, 187(1), 157-172. Rigon, R., Rodriguez-Iturbe, I., Maritan, A., Giacometti. A., Tarboton, D. G., & Rinaldo, A. (1996). On Hack's Law. Water Resources Research, 32(11), 3367-3374. Rodríguez-Iturbe, I., Ijjasz-Vasquez, E. J., Bras, R. L., & Tarboton, D. G. (1992). Power law distributions of discharge mass and energy in river basins. Water Resources Research, 28(4), 1089-1093.

Study of the 26Al(n,p)26Mg and 26Al(n,α)23Na reactions using the 27Al(p,p')27Al inelastic scattering reaction

International Nuclear Information System (INIS)

Benamara, S; De Séréville, N; Hammache, F; Stefan, I; Roussel, P; Ancelin, S; Assié, M; Guillot, J; Le Crom, B; Lefebvre, L; Adsley, P; Laird, A M; Barton, C; Diget, C; Fox, S; Coc, A; Deloncle, I; Hamadache, C; Kiener, J; Lefebfre-Schuhl, A

2016-01-01

26 Al was the first cosmic radioactivity ever detected in the galaxy as well as one of the first extinct radioactivity observed in refractory phases of meteorites. Its nucleosynthesis in massive stars is still uncertain mainly due to the lack of nuclear information concerning the 26 Al(n,p) 26 Mg and 26 Al(n,α) 23 Na reactions. We report on a single and coincidence measurement of the 27 Al(p,p') 27 Al(p) 26 Mg and 27 Al(p,p') 27 Al(α) 23 Na reactions performed at the Orsay TANDEM facility aiming at the spectroscopy study of 27 Al above the neutron threshold. Fourteen states are observed for the first time within 350 keV above the 26 Al+n threshold. (paper)

AlN/Al dual protective coatings on NdFeB by DC magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Li Jinlong; Mao Shoudong; Sun Kefei [Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Li Xiaomin [Shanghai Institute of Ceramics Chinese Academy of Sciences, Shanghai 200050 (China); Song Zhenlun [Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)], E-mail: songzhenlun@nimte.ac.cn

2009-11-15

AlN/Al dual protective coatings were prepared on NdFeB by DC magnetron sputtering in a home-made industrial apparatus. Comparing with Al coating, AlN/Al coatings have a denser structure of an outmost AlN amorphous layer following an inner Al columnar crystal layer. The coatings and NdFeB substrate combine well, and moreover, there is occurrence of metallurgy bonding in the interface layer. Both Al and AlN/Al coatings have a good protective ability to NdFeB. Especially, the corrosion resistance of AlN/Al coated NdFeB is improved largely. AlN/Al and Al protective coatings not only do not deteriorate the magnetic properties of NdFeB, but contribute to their slight increase.

AlN/Al dual protective coatings on NdFeB by DC magnetron sputtering

International Nuclear Information System (INIS)

Li Jinlong; Mao Shoudong; Sun Kefei; Li Xiaomin; Song Zhenlun

2009-01-01

AlN/Al dual protective coatings were prepared on NdFeB by DC magnetron sputtering in a home-made industrial apparatus. Comparing with Al coating, AlN/Al coatings have a denser structure of an outmost AlN amorphous layer following an inner Al columnar crystal layer. The coatings and NdFeB substrate combine well, and moreover, there is occurrence of metallurgy bonding in the interface layer. Both Al and AlN/Al coatings have a good protective ability to NdFeB. Especially, the corrosion resistance of AlN/Al coated NdFeB is improved largely. AlN/Al and Al protective coatings not only do not deteriorate the magnetic properties of NdFeB, but contribute to their slight increase.

The Relationship of Children's Predicted Behaviour to their Observed

African Journals Online (AJOL)

Dr Olaleye

The objective of this study was to assess the relationship of some Nigerian children's predicted behaviour to their observed behaviour ... study of children from low socio- economic families during their first dental visit, Hawley et al, ... An assessment of the behaviour of each child was made using Frankl's. Behaviour Rating ...

Comment on "Worldwide evidence of a unimodal relationship between productivity and plant species richness"

Science.gov (United States)

Tredennick, Andrew T.; Adler, Peter B.; Grace, James B.; Harpole, W Stanley; Borer, Elizabeth T.; Seabloom, Eric W.; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori A.; Brown, Cynthia S.; Buckley, Yvonne M.; Chu, Cheng-Jin; Collins, Scott L.; Crawley, Michael J.; Fay, Philip A.; Firn, Jennifer; Gruner, Daniel S.; Hagenah, Nicole; Hautier, Yann; Hector, Andy; Hillebrand, Helmut; Kirkman, Kevin P.; Knops, Johannes M. H.; Laungani, Ramesh; Lind, Eric M.; MacDougall, Andrew S.; McCulley, Rebecca L.; Mitchell, Charles E.; Moore, Joslin L.; Morgan, John W.; Orrock, John L.; Peri, Pablo L.; Prober, Suzanne M.; Risch, Anita C.; Schuetz, Martin; Speziale, Karina L.; Standish, Rachel J.; Sullivan, Lauren L.; Wardle, Glenda M.; Williams, Ryan J.; Yang, Louie H.

2016-01-01

Fraser et al. (Reports, 17 July 2015, p. 302) report a unimodal relationship between productivity and species richness at regional and global scales, which they contrast with the results of Adler et al. (Reports, 23 September 2011, p. 1750). However, both data sets, when analyzed correctly, show clearly and consistently that productivity is a poor predictor of local species richness.

Al-Si/Al2O3 in situ composite prepared by displacement reaction of CuO/Al system

Directory of Open Access Journals (Sweden)

Zhang Jing

2010-02-01

Full Text Available Al2O3 particle-reinforced ZL109 composite was prepared by in situ reaction between CuO and Al. The microstructure was observed by means of OM, SEM and TEM. The Al2O3 particles in sub-micron sizes distribute uniformly in the matrix, and the Cu displaced from the in situ reaction forms net-like alloy phases with other alloy elements. The hardness and the tensile strength of the composites at room temperature have a slight increase as compared to that of the matrix. However, the tensile strength at 350 ℃ has reached 90.23 MPa, or 16.92 MPa higher than that of the matrix. The mechanism of the reaction in the CuO/Al system was studied by using of differential scanning calorimetry(DSC and thermodynamic calculation. The reaction between CuO and Al involves two steps. First, CuO reacts with Al to form Cu2O and Al2O3 at the melting temperature of the matrix alloy, and second, Cu2O reacts with Al to form Cu and Al2O3 at a higher temperature. At ZL109 casting temperature of 750–780 ℃, the second step can also take place because of the effect of exothermic reaction of the first step.

AlGaN nanocolumns and AlGaN/GaN/AlGaN nanostructures grown by molecular beam epitaxy

Energy Technology Data Exchange (ETDEWEB)

Ristic, J.; Sanchez-Garcia, M.A.; Ulloa, J.M.; Calleja, E. [Departamento de Ingenieria Electronica, ETSI Telecomunicacion, Universidad Politecnica de Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Sanchez-Paramo, J.; Calleja, J.M. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Jahn, U.; Trampert, A.; Ploog, K.H. [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, 10117 Berlin (Germany)

2002-12-01

This work reports on the characterization of hexagonal, single crystal AlGaN nanocolumns with diameters in the range of 30 to 100 nm grown by molecular beam epitaxy on Si(111) substrates. The change of the flux ratio between the Al and the total III-element controls the alloy composition. The Al composition trend versus the Al flux is consistent both with the E{sub 2} phonon energy values measured by inelastic light scattering and the luminescence emission peaks position. High quality low dimensional AlGaN/GaN/AlGaN heterostructures with five GaN quantum discs, 2 and 4 nm thick, embedded into the AlGaN columns, were designed in order to study the quantum confinement effects. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

Mechanical Properties and Melt Quality Relationship of Sr-modified Al-12Si Alloy

Directory of Open Access Journals (Sweden)

Uludağa M.

2015-12-01

Full Text Available The formation of oxide film on the surface of aluminium melts, i.e. bifilms, are known to be detrimental when they are incorporated into the cast part. These defects causes premature fractures under stress, or aid porosity formation. In this work, Al-12 Si alloy was used to cast a step mould under two conditions: as-received and degassed. In addition, 10 ppi filters were used in the mould in order to prevent bifilm intrusion into the cast part. Reduced pressure test samples were collected for bifilm index measurements. Samples were machined into standard bars for tensile testing. It was found that there was a good agreement with the bifilm index and mechanical properties.

KONSEPSI AL-QURAN DAN AL-HADITS TENTANG OPERASIONAL BANK SYARIAH

Directory of Open Access Journals (Sweden)

Muhammad Ardy Zaini

2015-01-01

Full Text Available Islam hadir dengan beberapa tujuan, diantaranya adalah terciptanya khoirul ummah dan rahmatan lil’alamin dengan al-Qur’an dan al-Hadits sebagai penuntun umat Islam demi tercapainya tujuan tersebut. Sebagai pedoman hidup, al-Qur’an dan al-Hadits memberikan berbagai petunjuk tentang keteraturan dan permasalahan hidup, termasuk didalamnya mengenai perbankan yang telah memenuhi hampir separuh sisi-sisi kehidupan manusia. Untuk memaksimal ajaran syariah secara kaffah, maka nilai-nilai yang terdapat dalam al-Quran harus mampu diturunkan pada tataran praktis. Salah satu usaha dan langkah dalam rangka menemukan formula perbankan masa depan, al-Quran dan Hadits memiliki konsepsi dalam kegiatan operasional Bank Syariah. Hal ini dilakukan untuk membentuk sikap mental atau watak yang terjabarkan dalam pola berpikir, cara berbicara, dan etika bertingkah laku, sebagai ekspresi jiwa dari manusia yang beriman dan bertakwa kepada Allah Swt. Agar umat Islam mampu menjadi umat yang unggul (khayr ummah.

Fabrication of AlN-TiC/Al composites by gas injection processing

Institute of Scientific and Technical Information of China (English)

YU Huashun; CHEN Hongmei; MA Rendian; MIN Guanghui

2006-01-01

The fabrication of AlN-TiC/Al composites by carbon-and nitrogen-containing gas injection into Al-Mg-Ti melts was studied. It was shown that AlN and TiC particles could be formed by the in situ reaction of mixture gas (N2+C2H2+NH3) with Al-Mg-Ti melts. The condition for the formation of AlN was that the treatment temperature must be higher than 1373 K, and the amounts of AlN and TiC increased with the increase of the treatment temperature and the gas injection time.It was considered that AlN was formed by the direct reaction of Al with nitrogen-containing gas at the interface of the gas bubble and the melt. However, the mechanism of TiC formation is a combination mechanism of solution-precipitation and solid-liquid reaction.

Epitaxial growth of higher transition-temperature VO2 films on AlN/Si

Directory of Open Access Journals (Sweden)

Tetiana Slusar

2016-02-01

Full Text Available We report the epitaxial growth and the mechanism of a higher temperature insulator-to-metal-transition (IMT of vanadium dioxide (VO2 thin films synthesized on aluminum nitride (AlN/Si (111 substrates by a pulsed-laser-deposition method; the IMT temperature is TIMT ≈ 350 K. X-ray diffractometer and high resolution transmission electron microscope data show that the epitaxial relationship of VO2 and AlN is VO2 (010 ‖ AlN (0001 with VO2 [101] ‖   AlN   [ 2 1 ̄ 1 ̄ 0 ] zone axes, which results in a substrate-induced tensile strain along the in-plane a and c axes of the insulating monoclinic VO2. This strain stabilizes the insulating phase of VO2 and raises TIMT for 10 K higher than TIMT single crystal ≈ 340 K in a bulk VO2 single crystal. Near TIMT, a resistance change of about four orders is observed in a thick film of ∼130 nm. The VO2/AlN/Si heterostructures are promising for the development of integrated IMT-Si technology, including thermal switchers, transistors, and other applications.

Konsep Kepribadian Anak yang Shalihah dalam Kitab Al Akhlaq Lil Banat

Directory of Open Access Journals (Sweden)

Ulin Nadlifah Ummul Khoir

2015-12-01

research to find, collect, read, and analyze the books with no relevance to the research problem. To achieve success in the educational process, the material in the book al-Akhlaq lil Banat can be used as a reference in order to achieve educational success. The material presented in this book is not only refers to the relationship between man and God (transcendental, but also on the relationship between humans (anthropocentric, such as morality to parents, relatives, neighbors, peers and also to the adab or ordinances, such manners visit, walking, traveling, and so forth.   Kata kunci:    konsep pendidikan Islam, al-Akhlaq lil Banat, pribadi shalihah

The formation of AlB2 in an Al-B master alloy

International Nuclear Information System (INIS)

Wang Xiaoming

2005-01-01

The formation of borides in an Al-3 wt.%B master alloy, produced via chemical reactions of KBF 4 and aluminium has been investigated. The chemical reactions produce boron, which dissolves into molten aluminium and subsequently forms aluminium borides. Backscattered electron imaging (BEI) of the Al-3 wt.%B master alloy under a scanning electron microscope (SEM) revealed the presence of two types of phases that contain different levels of boron. Combined with X-ray diffraction (XRD) results, the two types of phases are identified as AlB 2 on AlB 12 . This gives a direct evidence for a peritectic reaction of AlB 12 and aluminium, which produces AlB 2 . The thermodynamic properties of the reactions that may be involved are examined, and the presence of AlB 12 phase in the master alloy explained. The observed microstructure is explained according to the peritectic reaction in an Al-B phase diagram. The stability of AlB 2 and AlB 12 at lower temperature than 975 deg. C is clarified

Construction and evaluation of multi-component Zn-Al based bearing alloys (Zn-Al-Si, Zn-Al-Cu)

International Nuclear Information System (INIS)

Shahmiri, M.; Shahin, K.

2001-01-01

Zn-Al based alloys, with excellent mechanical properties, are finding increasing applications in various industries, especially bearing and bushing fields. Observed dimensional instabilities, in their multicomponent systems, (e. g. Zn-Al-Si and, Zn-Al Si-Cu), is believed to be as the result of some kinds of phase transformation, due to the temperature variations, while in service. Profound understanding of the phase transformations due to the temperature variation, requires detailed evaluations of the isothermal sections of the multi-components phase diagrams of Zn-Al-Si and, Zn-Al-Si-Cu alloy systems. In the present article, the isothermal sections of the aforementioned ternary and quaternary systems in the solid state regions have been investigated and observed phase transitions have been critically evaluated

The Existence of a Designer Al=Al Double Bond in the LiAl2 H4- Cluster Formed by Electronic Transmutation.

Science.gov (United States)

Lundell, Katie A; Zhang, Xinxing; Boldyrev, Alexander I; Bowen, Kit H

2017-12-22

The Al=Al double bond is elusive in chemistry. Herein we report the results obtained via combined photoelectron spectroscopy and ab initio studies of the LiAl 2 H 4 - cluster that confirm the formation of a conventional Al=Al double bond. Comprehensive searches for the most stable structures of the LiAl 2 H 4 - cluster have shown that the global minimum isomer I possesses a geometric structure which resembles that of Si 2 H 4 , demonstrating a successful example of the transmutation of Al atoms into Si atoms by electron donation. Theoretical simulations of the photoelectron spectrum discovered the coexistence of two isomers in the ion beam, including the one with the Al=Al double bond. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quasicrystalline and crystalline phases in Al65Cu20(Fe, Cr)15 alloys

International Nuclear Information System (INIS)

Liu, W.; Koester, U.; Mueller, F.; Rosenberg, M.

1992-01-01

Two types of icosahedral quasicrystals are observed in Al 65 Cu 20 Fe 15-x Cr x (0 ≤ x ≤ 15) alloys, the face-centred AlCuFe-type icosahedral phase with dissoluted Cr and the primitive AlCuCr-type icosahedral phase with dissoluted Fe. In the vicinity of Al 65 Cu 20 Fe 8 Cr 7 a stable decagonal phase (a=0.45 nm and c=1.23 nm) forms competitively with the icosahedral quasicrystals. All these three quasicrystalline phases can be regarded as Hume-Rothery phases stabilized by the energy band factor. The density is measured to be 4.57, 4.44, and 4.11 g/cm 3 for the icosahedral Al 65 Cu 20 Fe 15 , the decagonal Al 65 Cu 20 Fe 8 Cr 7 , and the icosahedral Al 65 Cu 20 Cr 15 alloys, respectively. Depending on the composition in the range between Al 65 Cu 20 Fe 8 Cr 7 and Al 65 Cu 20 Cr 15 , several crystalline phases are observed during the transormation of the AlCuCr-type icosahedral phase: the 1/1-3/2-type orthorhombic (o) and the 1/0-3/2-type tetragonal (t) approximants of the decagonal phase, a hexagonal (h) phase, as well as a long-range vacancy ordered τ 3 -phase derived from a CsCl-type structure with a=0.2923 nm. The structures of all the crystalline phases are closely related to those of the icosahedral (i) and decagonal (d) quasicrystals, which leads to a definite orientation relationship as follows: i5 parallel d10 parallel o[100] parallel t[100] parallel h[001] parallel τ 3 [110]. (orig.)

Characterization of N-polar AlN in GaN/AlN/(Al,Ga)N heterostructures grown by metal-organic chemical vapor deposition

Science.gov (United States)

Li, Haoran; Mazumder, Baishakhi; Bonef, Bastien; Keller, Stacia; Wienecke, Steven; Speck, James S.; Denbaars, Steven P.; Mishra, Umesh K.

2017-11-01

In GaN/(Al,Ga)N high-electron-mobility transistors (HEMT), AlN interlayer between GaN channel and AlGaN barrier suppresses alloy scattering and significantly improves the electron mobility of the two-dimensional electron gas. While high concentrations of gallium were previously observed in Al-polar AlN interlayers grown by metal-organic chemical vapor deposition, the N-polar AlN (Al x Ga1-x N) films examined by atom probe tomography in this study exhibited aluminum compositions (x) equal to or higher than 95% over a wide range of growth conditions. The also investigated AlN interlayer in a N-polar GaN/AlN/AlGaN/ S.I. GaN HEMT structure possessed a similarly high x content.

KRITIK ATAS KRITIK EPISTEMOLOGI TAFSIR M. ABIED AL JABIRI: Studi Kritis atas Madkhal ila al Quran al Karim

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Ahmad Fawaid

2015-12-01

Full Text Available This paper critically views the epistemology of Muhammad Abid al Jabiri’s interpretation in his book, Madkhal ila al Quran al Karim. His latest work is projected to make the Quran relevant to mankind today and with certainly critiquing classical Quranic studies that have been constructed by previous scholars. Starting from Arab criticism, which is expected to synergize the gap between Turath and modernity, al Jabiri tried out his theory in the realm of Quranic studies oriented to maintain its originality and interpretation from sectarian influence. Focusing on al Jabiri’s review on the Quran, this paper examines and associates some of the problems with the epistemology of critique in Arab reasoning. Finally, it is inferred that the epistemologic offer of al Jabiri used in Turath is not fully applicable in Quranic studies for several reasons. First, the Quranic studies existed within the chain of sanad in its formation. Secondly, at the application stage, al Jabri often overlooked the sanad and narrations from the companions.

Electron irradiation response on Ge and Al-doped SiO 2 optical fibres

Science.gov (United States)

Yaakob, N. H.; Wagiran, H.; Hossain, I.; Ramli, A. T.; Bradley, D. A.; Hashim, S.; Ali, H.

2011-05-01

This paper describes the thermoluminescence response, sensitivity, stability and reproducibility of SiO 2 optical fibres with various electron energies and doses. The TL materials that comprise Al- and Ge-doped silica fibres were used in this experiment. The TL results are compared with those of the commercially available TLD-100. The doped SiO 2 optical fibres and TLD-100 are placed in a solid phantom and irradiated with 6, 9 and 12 MeV electron beams at doses ranging from 0.2 to 4.0 Gy using the LINAC at Hospital Sultan Ismail, Johor Bahru, Malaysia. It was found that the commercially available Al- and Ge-doped optical fibres have a linear dose-TL signal relationship. The intensity of TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre.

Electron irradiation response on Ge and Al-doped SiO2 optical fibres

International Nuclear Information System (INIS)

Yaakob, N.H.; Wagiran, H.; Hossain, I.; Ramli, A.T.; Bradley, D.A; Hashim, S.; Ali, H.

2011-01-01

This paper describes the thermoluminescence response, sensitivity, stability and reproducibility of SiO 2 optical fibres with various electron energies and doses. The TL materials that comprise Al- and Ge-doped silica fibres were used in this experiment. The TL results are compared with those of the commercially available TLD-100. The doped SiO 2 optical fibres and TLD-100 are placed in a solid phantom and irradiated with 6, 9 and 12 MeV electron beams at doses ranging from 0.2 to 4.0 Gy using the LINAC at Hospital Sultan Ismail, Johor Bahru, Malaysia. It was found that the commercially available Al- and Ge-doped optical fibres have a linear dose-TL signal relationship. The intensity of TL response of Ge-doped fibre is markedly greater than that of the Al-doped fibre.

[On the relationship between emotional dependency and abuse].

Science.gov (United States)

Leemans, C; Loas, S

2016-01-01

Abuse is a complex psychosocial issue with multiple implications. This paper takes a look at the physical and psychological manifestations of domestic violence, i.e. between adult (romantic) partners as well as abuse of the elderly. Past studies have looked at the relationship between emotional dependency, the occurence and sustainability of abuse and the likehood that a victimized person will terminate a relationship. Indeed, individuals with Dependent Personality Disorder (DPD) or with dependent characteristics present a higher risk of becoming abusive (both physically and mentally) as well as becoming a victim of abuse. Regarding the elderly, the concept of "reverse violence"--where the current abuser was the victim of the senior who is being abused-, also entails dependent relationships. We identified three concepts that are necessary in the understanding of how dependent relationships underpin abuse: Rusbult's model of commitment in intimate relationships, the notion of dependency-possessiveness and Murphy et al's notion of escalating affective dependency. Thus, it is imperative that future studies in the field of domestic violence look at the dynamics of dyads rather than the individuals alone.

Study on adsorption of rhodamine B onto Beta zeolites by tuning SiO2/Al2O3 ratio.

Science.gov (United States)

Cheng, Zhi-Lin; Li, Yan-Xiang; Liu, Zan

2018-02-01

The exploration of the relationship between zeolite composition and adsorption performance favored to facilitate its better application in removal of the hazardous substances from water. The adsorption capacity of rhodamine B (RB) onto Beta zeolite from aqueous solution was reported. The relationship between SiO 2 /Al 2 O 3 ratio and adsorption capacity of Beta zeolite for RB was explored. The structure and physical properties of Beta zeolites with various SiO 2 /Al 2 O 3 ratios were determined by XRD, FTIR, TEM, BET, UV-vis and so on characterizations. The adsorption behavior of rhodamine B onto Beta zeolite matched to Langmuir adsorption isotherm and more suitable description for the adsorption kinetics was a pseudo-second-order reaction model. The maximum adsorption capacity of the as-prepared Beta zeolite with SiO 2 /Al 2 O 3 = 18.4 was up to 27.97mg/g. Copyright © 2017 Elsevier Inc. All rights reserved.

Structural and electronic properties of ScxAl1−xN: First principles study

International Nuclear Information System (INIS)

Berkok, Houria; Tebboune, Abdelghani; Saim, Asmaa; Belbachir, Ahmed H

2013-01-01

The structural and electronic properties of Sc x Al 1−x N ternary semiconductor alloys are investigated in the rocksalt, zinc blend and wurtzite structures using the full potential linear muffin tin orbitals (FP-LMTO) method. The local density approximation (LDA) was used for the exchange and correlation energy density functional. In particular, the lattice constant, bulk modulus and band gap energies of ScN and AlN compounds and their ternary alloys Sc x Al 1−x N are calculated in rocksalt, zinc blend and wurtzite structures and discussed. A linear relationship has obtained for equilibrium lattice constants versus Sc concentration for rocksalt and zinc blend structures. The band gap is decreased with the increasing of Sc concentration in the rocksalt phase. For ZB-Sc x Al 1−x N, the band gap is the largest one at x=0.25 and changes from indirect to direct when x is more than 0.25

Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

International Nuclear Information System (INIS)

Li, Shuo; Bhushan, Bharat

2016-01-01

Highlights: • Mg/Al-, Zn/Al- and Zn/Mg/Al-layered double hydroxide were synthesized. • Mg/Al-LDH had superior tribological performance compared to other LDHs. • The best thermal stability of Mg/Al-LDH was responsible for its friction property. - Abstract: Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

Energy Technology Data Exchange (ETDEWEB)

Li, Shuo [School of Materials Science and Technology, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian Distract, Beijing 100083 (China); Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States); Bhushan, Bharat, E-mail: bhushan.2@osu.edu [Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States)

2016-08-15

Highlights: • Mg/Al-, Zn/Al- and Zn/Mg/Al-layered double hydroxide were synthesized. • Mg/Al-LDH had superior tribological performance compared to other LDHs. • The best thermal stability of Mg/Al-LDH was responsible for its friction property. - Abstract: Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

Dakwah Kultural Bayt al-Qur’an al-Akbar Ukiran Kayu Khas Melayu Palembang

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Reza Pahlevi

2016-07-01

Full Text Available Penelitian ini berusaha mengungkap berbagai fenomena yang menggambarkan serangkaian kegiatan dakwah kultural Bayt al-Qur’an al-Akbar Ukiran Khas Melayu Palembang. Sehingga dapat diperoleh sejumlah informasi mengenai berbagai upaya penerapan program yang dimaksud. Penelitian ini dapat disimpulkan, pertama kontribusi Bayt al-Qur’an al-Akbar Ukiran Khas Melayu Palembang terhadap perkembangan metode dakwah kultural adalah dakwah melalui seni. Kedua, Bayt al-Qur’an al-Akbar Ukiran Khas Melayu Palembang sebagai tempat Wisata Religi yang sangat signifikan.   This research tries to reveal the various phenomenon that describe a series of cultural propaganda activities Bayt al-Qur’an al-Akbar Ukiran Khas Melayu Palembang. In order to obtain some informations about the efforts of the implementation of the program in question. It can be concluded, the first contribution of Bayt al-Qur’an al-Akbar Ukiran Khas Melayu Palembang on the development of methods of cultural propaganda is propaganda through art. Second Bayt al-Qur’an al-Akbar Ukiran Khas Melayu Palembang as a very significant Religious Tourism.

Al2O3 adherence on CoCrAl alloys

International Nuclear Information System (INIS)

Kingsley, L.M.

1980-04-01

Adherence of protective oxides on NiCrAl and CoCrAl superalloys has been promoted by a dispersion of a highly oxygen reactive element or its oxide being produced within the protection system. Two aspects of this subject are investigated here: the use of Al 2 O 3 as both the dispersion and protective oxide; and the production of an HfO 2 dispersion while simultaneously aluminizing the alloy. It was found that an Al 2 O 3 dispersion will act to promote the adherence of an external scale of Al 2 O 3 to a degree comparable to previously tested dispersions and an HfO 2 dispersion comparable to that produced by a Rhines pack treatment is produced during aluminization

Tracing Al Shabaab’s Decision to Cooperate with Al Qaeda in Somalia (2008

Directory of Open Access Journals (Sweden)

Adlini Ilma Ghaisany Sjah

2014-02-01

Full Text Available 'Al Shabaab, a Somali insurgent with predominantly nationalistic causes (alongside transnational [global Jihad] and Islamic goals made the choice to fight on behalf of Al Qaeda in 2008. The decision to do so contrasted with Al Shabaab’s previous behaviour of actively denying cooperation and distancing itself from Al Qaeda. This study aims to uncover factors that contributed to Al Shabaab’s decision through the use of process-tracing. The results show that Al Shabaab’s declaration of cooperation with Al Qaeda in August 2008 was brought about by a series of events that traced back to four factors: public reactions to the implementation of a Salafi ideology, the shift to a radical leadership, Al Shabaab’s inability to maintain stability in areas under its control and its increasing attacks by Al Shabaab on the Somali public. Al Shabaab pursued cooperation with Al Qaeda after realizing that their nationalistic preference was no longer achievable in the near future.' ' '

Reconstructing Data Flow Diagrams from Structure Charts Based on the Input and Output Relationship

OpenAIRE

YAMAMOTO, Shuichiro

1995-01-01

The traceability of data flow diagrams against structure charts is very important for large software development. Specifying if there is a relationship between a data flow diagram and a structure chart is a time consuming task. Existing CASE tools provide a way to maintain traceability. If we can extract the input-output relationship of a system from a structure chart, the corresponding data flow diagram can be automatically generated from the relationship. For example, Benedusi et al. propos...

All About ALS

Science.gov (United States)

... Subscribe August 2015 Print this issue All About ALS Understanding a Devastating Disorder En español Send us ... Sports Concussions Wise Choices How Can I Help ALS Research? If you have ALS, join the National ...

Atomistic simulations of diffusion mechanisms in off-stoichiometric Al-rich Ni3Al

International Nuclear Information System (INIS)

Duan, Jinsong

2007-01-01

This paper presents dynamics simulation results of diffusion in off-stoichiometric Al-rich Ni 3 Al (Ni 73 Al 27 ) at temperature ranging from 1300 to 1550 K. The interatomic forces are described by the Finnis-Sinclair type N-body potentials. Particular attention is devoted to the effect of the extra 2% of Al atoms sitting on the Ni sublattice as antisite point defects (Al Ni ) on diffusion. Simulation results show that Ni atoms mainly diffuse through the Ni sublattice at the temperatures investigated. Al atoms diffuse via both the intrasublattice and antistructure bridge (ASB) mechanisms. The contribution to Al diffusion from the ASB mechanism decreases at the lower temperature (T Ni ) enhances both Al and Ni diffusion in Ni 73 Al 27 . The Ni-Al coupled diffusion effect is observed and understood at the atomic level for the first time

Hypermetabolism in ALS is associated with greater functional decline and shorter survival.

Science.gov (United States)

Steyn, Frederik J; Ioannides, Zara A; van Eijk, Ruben P A; Heggie, Susan; Thorpe, Kathryn A; Ceslis, Amelia; Heshmat, Saman; Henders, Anjali K; Wray, Naomi R; van den Berg, Leonard H; Henderson, Robert D; McCombe, Pamela A; Ngo, Shyuan T

2018-04-29

To determine the prevalence of hypermetabolism, relative to body composition, in amyotrophic lateral sclerosis (ALS) and its relationship with clinical features of disease and survival. Fifty-eight patients with clinically definite or probable ALS as defined by El Escorial criteria, and 58 age and sex-matched control participants underwent assessment of energy expenditure. Our primary outcome was the prevalence of hypermetabolism in cases and controls. Longitudinal changes in clinical parameters between hypermetabolic and normometabolic patients with ALS were determined for up to 12 months following metabolic assessment. Survival was monitored over a 30-month period following metabolic assessment. Hypermetabolism was more prevalent in patients with ALS than controls (41% vs 12%, adjusted OR=5.4; pALS. Mean lower motor neuron score (SD) was greater in hypermetabolic patients when compared with normometabolic patients (4 (0.3) vs 3 (0.7); p=0.04). In the 12 months following metabolic assessment, there was a greater change in Revised ALS Functional Rating Scale score in hypermetabolic patients when compared with normometabolic patients (-0.68 points/month vs -0.39 points/month; p=0.01). Hypermetabolism was inversely associated with survival. Overall, hypermetabolism increased the risk of death during follow-up to 220% (HR 3.2, 95% CI 1.1 to 9.4, p=0.03). Hypermetabolic patients with ALS have a greater level of lower motor neuron involvement, faster rate of functional decline and shorter survival. The metabolic index could be important for informing prognosis in ALS. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Methodology and Characteristics of Zad al-masir fi ‘ilm al-tafsirby AllamaIbn al-Jawzī (Urdu

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Dr. Muhammad Riaz al Azhari

2017-01-01

Full Text Available This article describes the methodology and characteristics of Zad al-masir fi ‘ilm al-tafsir. This is one the finest work of AllamaIbn al-Jawzī, a 6th century prominent Interpreter. Several editions of this Tafsir have been published. However, the edition of dar al-kitab al-‘arbi, Beirut published in four volumes is selected for this study. This exegesis is based on conventional narrations, authentic quotations from the Islamic Scholars and lingual & grammatical discussions. As a witness, causes of verses (asbabal-Nuz┴l,Makki and MadaniSurah’s (chapters, the abrogating and abrogated verses (al-nasikhwal-mans┴kh and Islamic jurisprudence have been discussed in it where needed. The quality of this translation which is admirable is that mostly authentic Ahadith from original sources, and references to well known basic books in relevant discussions have been described. `

Phenotypic and genotypic studies of ALS cases in ALS-SMA families.

Science.gov (United States)

Corcia, Philippe; Vourc'h, Patrick; Blasco, Helene; Couratier, Philippe; Dangoumau, Audrey; Bellance, Remi; Desnuelle, Claude; Viader, Fausto; Pautot, Vivien; Millecamps, Stephanie; Bakkouche, Salah; Salachas, FranÇois; Andres, Christian R; Meininger, Vincent; Camu, William

2018-03-01

Amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are the most frequent motor neuron disorders in adulthood and infancy, respectively. There is a growing literature supporting common pathophysiological patterns between those disorders. One important clinical issue for that is the co-occurrence of both diseases within a family. To collect families in which ALS and SMA patients co-exist and describe the phenotype and the genotype of ALS patients. Nine families with co-occurrence of SMA and ALS have been gathered over the last 15 years. Epidemiological, phenotype and genetic status were collected. Out of the nine families, six corresponded to the criteria of familial ALS (FALS). Clinical data were available for 11 patients out of the 15 ALS cases. Mean age of onset was 58.5 years, site of onset was lower limbs in nine cases (81.8%), median duration was 22 months. Four ALS patients carried a mutation: three mutations in SOD1 gene (G147N in two cases and one with E121G) and one repeat expansion in the C9ORF72 gene. Three patients had abnormal SMN1 copy numbers. While the high proportion of familial history of ALS cases in these ALS-SMA pedigrees could have suggested that these familial clusters of the two most frequent MND rely on a genetic background, we failed to exclude that this occurred by chance.

Eutectic microstructures of Al-ThA13 and Al-UA14 alloys

International Nuclear Information System (INIS)

Vieira, R.R.; Ambrozio Filho, F.

1990-01-01

This paper deals on the microstructures of systems Al-ThAl3 and Al-UAL4, which are composed by a non faceted phase (aluminium) and an intermetallic phase (ThAl3 or UAL4) which is normally faceted phase. (C.M.)

Relationship between the catalytic activity of Pt/alumina and the relaxation process of the photoexcited electrons

Energy Technology Data Exchange (ETDEWEB)

Ito, Junji, E-mail: j-itou@mail.nissan.co.jp [Advanced Materials Laboratory, Nissan Research Center, NISSAN MOTOR CO., LTD., 1 Natsushima-cho, Yokosuka-shi, Kanagawa 237-8523 (Japan); Department of Applied Physics and Chemistry, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Hanaki, Yasunari [Advanced Materials Laboratory, Nissan Research Center, NISSAN MOTOR CO., LTD., 1 Natsushima-cho, Yokosuka-shi, Kanagawa 237-8523 (Japan); Shen, Qing [Department of Applied Physics and Chemistry, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Department of Engineering Science, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Toyoda, Taro [Department of Applied Physics and Chemistry, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan); Department of Engineering Science, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan)

2012-12-15

Highlights: Black-Right-Pointing-Pointer We determined the decay time of photoexcited electrons of Pt/Al{sub 2}O{sub 3}. Black-Right-Pointing-Pointer Faster decay of excited electrons in Pt/Al{sub 2}O{sub 3} leads to its faster oxidation rate. Black-Right-Pointing-Pointer Decreasing excited electron lifetime in Pt/Al{sub 2}O{sub 3} may decrease Pt consumption in catalytic convertors. - Abstract: In order to decrease the consumption of precious metals used in the catalytic converters used in automobiles, we studied the relationship between the catalytic activity of Pt/alumina (Pt/Al{sub 2}O{sub 3}) and the relaxation process of photoexcited electrons. Firstly, we studied the relationship between the size of the Pt particles in Pt/Al{sub 2}O{sub 3} and catalytic performance. Secondly, the relationship between the size of the Pt particles in Pt/Al{sub 2}O{sub 3} and the decay time of the excited electrons was studied using an improved transient grating (TG) technique. The results showed that faster decay of the excited electrons leads to greater oxidation rates. The decay time obtained with the improved TG technique gives an indication of the time that the exited electrons take to return to the ground state. According to studies utilizing FT-IR, one of the processes necessary for quickly generating CO{sub 2} with Pt is that the electron in the Pt-O bond moves to the Pt side and that the Pt{sup +} becomes Pt metal. Thus, the decay time obtained with the improved TG technique corresponds to the process whereby Pt{sup +} returns to Pt metal. Thus, we found that the consumption of precious metals can be reduced by increasing the speed of the decay of the excited electrons.

Are Clusters Races? A Discussion of the Rhetorical Appropriation of Rosenberg et al.'s “Genetic Structure of Human Populations”

Directory of Open Access Journals (Sweden)

Melissa Wills

2017-01-01

Full Text Available Noah Rosenberg et al.'s 2002 article “Genetic Structure of Human Populations” reported that multivariate genomic analysis of a large cell line panel yielded reproducible groupings (clusters suggestive of individuals' geographical origins. The paper has been repeatedly cited as evidence that traditional notions of race have a biological basis, a claim its authors do not make. Critics of this misinterpretation have often suggested that it follows from interpreters' personal biases skewing the reception of an objective piece of scientific writing. I contend, however, that the article itself to some degree facilitates this misrepresentation. I analyze in detail several verbal and visual features of the original article that may predispose aspects of its racial interpretation; and, tracing the arguments of one philosopher and one popular science writer, I show how these features are absorbed, transformed into arguments for a biological basis of race, and re-attributed to the original. The essay demonstrates how even slight ambiguities can enable the misappropriation of scientific writing, unintentionally undermining the authors' stated circumspection on the relationship between cluster and race.

Piaget's Geographical Spatial Stages: An Examination of Their Relationship to Elementary Children's Classification-Class Inclusion Abilities.

Science.gov (United States)

Rand, David C.; Towler, John O.

This study examines the relationship between a child's concept of geographic and territorial relationships and his competence on classification and class inclusion measures. Jean Piaget's stages of development and studies conducted by other investigators (Jahoda, 1964; Stoltman, 1971; Rand and Towler, 1973; Flavell, 1963; Asher, et al, 1971;…

Interface reactions in the Al-Si-SiC and Mg-Al-Al{sub 2}O{sub 3} composite systems

Energy Technology Data Exchange (ETDEWEB)

Johnson, P.K. [Commission of the European Communities, Petten (Netherlands). Inst. for Advanced Materials; Fazal-Ur-Rehman [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials; Fox, S. [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials; Flower, H.M. [Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Materials; West, D.R.F.

1995-12-31

Structural and compositional observations are reported on the influence of the interfaces on the mechanisms and kinetics of liquid metal-ceramic reactions in Al-SiC, Al-Si-SiC, Mg-Al{sub 2}O{sub 3} and Mg-Al-Al{sub 2}O{sub 3} composites. The aluminium based materials contained up to 20 vol% SiC in particulate form, and were produced by a spray casting process; subsequently the interface reactions were studied in samples heated to temperatures up to 1100 C. The reaction product was Al{sub 4}C{sub 3} in both Al-SiC and Al-Si-SiC composites. The influence of the crystallography and topology of the SiC particle surfaces on the nucleation of the Al{sub 4}C{sub 3} has been demonstrated; surface asperities play an important role. Growth of nuclei proceeds to form continuous reaction product layers which control the subsequent kinetics. The magnesium based composites contained 5 vol% Al{sub 2}O{sub 3} fibres (3 {mu}m in diameter), and were produced by a liquid infiltration process. SD Safimax fibres with relatively low and high porosity, and also RF Saffil fibres, with a silica binder, were investigated. Fibre porosity plays a major role in accelerating the penetration of Mg into the fibres with reaction to form MgO. Silica binder on the fibre surface transforms to MgO. The reaction rate was reduced by the presence of aluminium in the matrix. The factors controlling the reactions in the aluminium and magnesium based composites are compared. (orig.)

Progress of the relationship between serum uric acid and neurodegenerative diseases

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Yang FU

2018-04-01

Full Text Available Serum uric acid (sUA, a natural antioxidant in human body, has been found to be related to the occurrence and development of various neurodegenerative diseases in recent years, including Parkinson's disease (PD, multiple system atrophy (MSA, Alzheimer's disease (AD and amyotrophic lateral sclerosis (ALS. Increasing of sUA level has been found to reduce the incidence of PD and ALS, but the relationship between sUA and AD, MSA remains largely unknown. The in vitro studies and animal experiments revealed that sUA can enhance the antioxidant capacity of neurons and delay neurodegeneration and apoptosis. This paper mainly reviews the progress in epidemiological and basic studies of the relationship between sUA and neurodegenerative diseases in recent years, and aims to provide a reference for future novel prevention and treatment strategies for neurodegenerative diseases. DOI: 10.3969/j.issn.1672-6731.2018.03.010

Effect of temperature and hydroxy-Al interlayers on Cs selectivity and fixation in river suspensions and soils. Final report

International Nuclear Information System (INIS)

Zelazny, L.W.; Martens, D.C.; El-Prince, A.M.; Rich, C.I.

1978-01-01

The adsorption of 137/sub Cs/ by sediments from the Savannah River Plant follows a theoretically expected linear relationship between ln Kd and l/T where kd and T are the equilibrium distribution coefficient and the temperature in kelvins, respectively. The slope of these plots decreases after removal of hydroxy Al interlayers. Hydroxy Al interlayers thus make Cs + adsorption more temperature dependent. The phenomenon is explained by considering hydroxy Al interlayers as a source of hydronium ions H 3 O + , which compete with Cs for exchange positions in wedge zones. An increase in temperature favors an increase in H 3 O ions, which in turn favors less adsorption of Cs + . Aside from their thermal effect the positively charged hydroxy aluminum polymeric groups drastically decrease the cation exchange capacity and, consequently, the adsorption of cesium. The adsorption of trace radioactive cesium by sediments from the Savannah River Plant area also follows a theoretically expected linear relationship between ln Kd and the pH of the equilibrium solution. Theoretically, the slope of these plots is proportional to the fraction of surface area occupied by pH dependent charges. Experimentally, the slope becomes zero after removal of hydroxy Al interlayers. Hydroxy Al interlayers are thus the main source for the pH dependent charges, making Cs + adsorption pH dependent also

Evaluation of liquid fragility and thermal stability of Al-based metallic glasses by equivalent structure parameter

International Nuclear Information System (INIS)

Li Xuelian; Bian Xiufang; Hu Lina

2010-01-01

Based on extended Ideal-Atomic-Packing model, we propose an equivalent structure parameter '6x+11y' to evaluate fragility and thermal stability of Al-TM-RE metallic glasses, where x and y are composition concentrations of transition metal (TM) and rare earth (RE), respectively. Experimental results show that glass forming compositions with '6x+11y' near 100 have the smallest fragility parameter and best structure stability. In addition, '6x+11y' parameter has a positive relationship with onset-crystallization temperature, T x . Al-TM-RE glassy alloys with (6x+11y)≤100 undergo primary crystallization of fcc-Al nanocrystals, while alloys with (6x+11y)>100 exhibit nanoglassy or glassy crystallization behavior.

KONSTRUKSI FIQH BUKHARI DALAM KITAB AL-JAMI’ AL-SHAHIH

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Abdul Sattar

2011-06-01

Popularitas Imam Bukhari sebagai penyusun kitab Hadits memiliki posisi yang tinggi di kalangan masyarakat muslim. Kitab Al-Jami ‘al-Shahih karya Imam  Bukhari dianggap sebagai koleksi hadits terbaik setelah Quran. Namun, tidak ada banyak informasi tentang kemampuannya di bidang Hukum Islam (fiqh. Ada beberapa pertanyaan yang dapat diajukan dalam hal tersebut;  pertama, apakah pemikiran Imam Bukhari dipengaruh salah satu dari empat fuqaha Sunni saat menulis al-Jami ‘al-Shahih?. Kedua, apa yang diupayakan Imam Bukhari untuk mengartikulasikan pemikirannya tentang hukum Islam? Dengan menggunakan pendekatan eksploratif, verifikatif dan hermenetical, artikel ini akan mengungkapkan bahwa Imam Bukhari tidak berada di bawah pengaruh madhab tertentu dalam mengartikulasikan pemikirannya tentang hukum Islam. Dia mengartikulasikan pandangannya dengan cara yang unik dan execelent berdasarkan kapasitasnya sebagai muhaddits.

The Complex Interplay Between Depression/Anxiety and Executive Functioning: Insights From the ECAS in a Large ALS Population

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Solca, Federica; Faini, Andrea; Madotto, Fabiana; Lafronza, Annalisa; Monti, Alessia; Zago, Stefano; Doretti, Alberto; Ciammola, Andrea; Ticozzi, Nicola; Silani, Vincenzo; Poletti, Barbara

2018-01-01

Introduction: The observed association between depressive symptoms and cognitive performances has not been previously clarified in patients with amyotrophic lateral sclerosis (pALS). In fact, the use of cognitive measures often not accommodating for motor disability has led to heterogeneous and not conclusive findings about this issue. The aim of the present study was to evaluate the relationship between cognitive and depressive/anxiety symptoms by means of the recently developed Edinburgh Cognitive and Behavioral ALS Screen (ECAS), a brief assessment specifically designed for pALS. Methods: Sample included 168 pALS (114 males, 54 females); they were administered two standard cognitive screening tools (FAB; MoCA) and the ECAS, assessing different cognitive domains, including ALS-specific (executive functions, verbal fluency, and language tests) and ALS non-specific subtests (memory and visuospatial tests). Two psychological questionnaires for depression and anxiety (BDI; STAI/Y) were also administered to patients. Pearson’s correlation coefficient was used to assess the degree of association between cognitive and psychological measures. Results: Depression assessment negatively correlated with the ECAS, more significantly with regard to the executive functions subdomain. In particular, Sentence Completion and Social Cognition subscores were negatively associated with depression levels measured by BDI total score and Somatic-Performance symptoms subscore. Conversely, no significant correlations were observed between depression level and cognitive functions as measured by traditional screening tools for frontal abilities (FAB) and global cognition (MoCA) assessment. Finally, no significant correlations were observed between state/trait anxiety and the ECAS. Discussion and conclusion: This represents the first study focusing on the relationship between cognitive and psychological components in pALS by means of the ECAS, the current gold standard for ALS cognitive

Relationships between central and peripheral corneal thickness in different degrees of myopia.

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Ortiz, Sara; Mena, Laura; Rio-San Cristobal, Ana; Martin, Raul

2014-01-01

To analyze the relationship between the central corneal thickness (CCT) and mid-peripheral corneal thickness (PCT) with the degree of myopia [axial length (AL) and spherical equivalent refractive error (SE)]. 175 right myopic eyes from 175 patients were divided according to the degree of SE: group #1 (n=76, 12.00 D). The CCT and PCT (3mm from the apex to the superior, inferior, nasal and temporal locations) were measured with the Orbscan-II. Relative peripheral index (RPI) was calculated by dividing the PCT by the CCT. The AL was measured with the IOL Master, and the SE was obtained with subjective refraction. AL was 25.18±1.16 mm, 26.59±1.26 mm and 29.45±2.58 mm and SE was -3.31±1.40 D, -8.32±1.64 D and -16.44±4.48 D for groups #1, #2 and #3, respectively. Non-statistically significant differences in central and peripheral corneal thickness were found between groups (P>0.05 ANOVA). Non-significant relationship was found between central and peripheral corneal thickness with the AL and SE in the three study groups and in the total sample (r0.05). The RPI values were similar between groups without significant difference between groups (P>0.05 ANOVA). Linear relationship was found between RPI superior location in group #2 (r=-0.23; P=0.04) and RPI nasal location in group #3 with the EE (r=0.41; P=0.03). There are no significant differences among low, moderate and extremely myopic eyes related to the CCT and PCT. Corneal thickness is very similar in myopic eyes with small differences that are not clinically relevant to myopic patient management. Copyright © 2012 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

Studying the Relationship between Organizational Innovation and System thought in Service Organization

OpenAIRE

Ali Margir; Nahid Tereh Eiduzehi; Zakaria Surizehi; Naser Kamaly Pur

2014-01-01

In this research, we study the relationship and effect of organizational innovation and its dimensions on system thought and the relationship between these two variables have been evaluated in better adaption process of service organizations with the environment and society. To collect data after defining validity and reliability, organizational innovation questionnaire of choopani & et al (2012) and system thought have been used the case statistical society includes all employees of water an...

The features of family relationship experience, style of parental bonding and relationship with family members of convicts

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Daiva Karkockienė

2016-01-01

Full Text Available The aim of this article is to reveal the features of family relationship, style of parental bonding and relationship with family members of convicts. The tasks of the research: 1 to analyse the relationships experienced in families of convicts and the subjectively perceived style of parental bonding in their childhood; 2 to assess the relationships of convicts (men and women with their families; 3 to compare the attachment styles of convicts analysing different close relationships (with parents, relatives, partner or a close friend. The research was carried out in Panevėžys Correctional Facility and Lukiškės Remand Prison – Closed Prison. In total, the research involved 63 subjects, out of whom 33 were men and 30 women. The female subjects were 18–64 years old, males – 18–45 years old. The following tools were used: Parental Bonding Instrument (Parker G. et al., 1997, Familial Relationship Quality Measure (Ryan & Willits, 2007, Experiences in Close Relationships-Revised (ECR – RS; Fraley, Waller, & Brennan, 2000 and demographic questionnaire. The findings have showed that were no statistically significant differences with regard to gender were established assessing the subjectively perceived style of parental bonding, satisfaction with familial relationships and the attachment style in different close relationships. Both male and female subjects attributed the subjectively perceived upbringing style of a father to “overprotection”, that of a mother – to “care”. The attachment style of males characterised as “avoidance” is insignificantly higher than females, whereas the “anxiety” style of attachment in samples of males and females showed almost no differences. A positive relationship was established between the satisfaction with experienced familial relationships and the “caring” style of upbringing of both parents. Satisfaction with familial relationships positively correlates with the importance of

Crystal Structure, Spectroscopic Investigations, and Physical Properties of the Ternary Intermetallic REPt2Al3 (RE = Y, Dy–Tm and RE2Pt3Al4 Representatives (RE = Tm, Lu

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Fabian Eustermann

2018-04-01

Full Text Available The REPt2Al3 compounds of the late rare-earth metals (RE = Y, Dy–Tm were found to crystallize isostructural. Single-crystal X-ray investigations of YPt2Al3 revealed an orthorhombic unit cell (a = 1080.73(6, b = 1871.96(9, c = 413.04(2 pm, wR2 = 0.0780, 942 F2 values, 46 variables with space group Cmmm (oC48; q2pji2hedb. A comparison with the Pearson database indicated that YPt2Al3 forms a new structure type, in which the Pt and Al atoms form a [Pt2Al3]δ− polyanion and the Y atoms reside in the cavities within the framework. Via a group-subgroup scheme, the relationship between the PrNi2Al3-type structure and the new YPt2Al3-type structure was illustrated. The compounds with RE = Dy–Tm were characterized by powder X-ray diffraction experiments. While YPt2Al3 is a Pauli-paramagnet, the other REPt2Al3 (RE = Dy–Tm compounds exhibit paramagnetic behavior, which is in line with the rare-earth atoms being in the trivalent oxidation state. DyPt2Al3 and TmPt2Al3 exhibit ferromagnetic ordering at TC = 10.8(1 and 4.7(1 K and HoPt2Al3 antiferromagnetic ordering at TN = 5.5(1 K, respectively. Attempts to synthesize the isostructural lutetium compound resulted in the formation of Lu2Pt3Al4 (Ce2Ir3Sb4-type, Pnma, a = 1343.4(2, b = 416.41(8, c = 1141.1(2 pm, which could also be realized with thulium. The structure was refined from single-crystal data (wR2 = 0.0940, 1605 F2 values, 56 variables. Again, a polyanion with bonding Pt–Al interactions was found, and the two distinct Lu atoms were residing in the cavities of the [Pt3Al4]δ– framework. X-ray photoelectron spectroscopy (XPS measurements were conducted to examine the electron transfer from the rare-earth atoms onto the polyanionic framework.

[The Terminal Phase of an Intractable Neurological Disease from the Viewpoint of Nursing Care: The Importance of the Promotion of a Barrier-Free Mind for ALS Care].

Science.gov (United States)

Muraoka, Koko

2015-08-01

Amyotrophic lateral sclerosis (ALS) is a particularly serious intractable neurological disease. Patients with ALS have high mortality rates if they are not put on an artificial respirator. Even with an artificial respirator, individuals with ALS are forced to witness their own physical deterioration. Because 24 hour care is usually required, an intense relationship ofter develops between patients with ALS and family caregivers. This relationship forms an invisible barrier and can impede a smooth introduction of external services. As a result, there can be a degradation in the quality of care. The purpose of this paper is to describe the voluntary efforts of patients and family caregivers in order to break down this barrier and to discuss what types of care support are available to promote barrier-free minds.

Relationship between Matern al Nutritional Status and Infant Birth Weight of Vegetarians in DKI Jakarta

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Sandra Fikawati

2012-06-01

Full Text Available Infant’s birth weight, especially low birth weight (LBW, areintergenerational issues that will affect the cycle of life.Vegetarian diets are at risk because limited food consumption could cause nutrient deficiencies. This retrospective studyaims to determine the relationship between maternal nutritional status (pre-pregnancy body mass index (BMI and weight gain during pregnancy and infant’s birth weight among vegetarians in Jakarta. The total sample of 85 children aged 1 month to 5 years was selected purposively. Results showed that the mean of pre-pregnancy BMI of vegetarian mothers is 20.2 kg/m2 (±2.2 kg/m2, pregnancy weight gain is 15.5 kg (±6.4 kg and infant’s birth weight is 3212 gs (±417.7 gs. Pre-pregnancy BMI and pregnancy weight gain were significantly associated with infant’s birth weight of vegetarians. There is no relationship between pre-pregnancy BMI and pregnancy weight gain. Multivariate analysis found that pre-pregnancy BMI, protein, vitamin B12, iron, and Zn intakes and sex has relationship with infant’s birthweight. It is recommended that vegetarian mothers should get information about the importance of pre-pregnancy nutrition, optimal pregnancy weight gain, and maintaining adequate intake of protein, vitamin B12, iron, and Zn during pregnancy

Cryptanalysis of Lin et al.'s Efficient Block-Cipher-Based Hash Function

NARCIS (Netherlands)

Liu, Bozhong; Gong, Zheng; Chen, Xiaohong; Qiu, Weidong; Zheng, Dong

2010-01-01

Hash functions are widely used in authentication. In this paper, the security of Lin et al.'s efficient block-cipher-based hash function is reviewed. By using Joux's multicollisions and Kelsey et al.'s expandable message techniques, we find the scheme is vulnerable to collision, preimage and second

From Kitāb al-ḥadā’iq to Kitāb al-dawā’ir: Reconsidering Ibn al-Sīd al-Batalyawsī’s Philosophical Treatise

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Eliyahu, Ayala

2015-06-01

Full Text Available The philosophical treatise known as Kitāb al-ḥadā’iq is generally ascribed to the 12th century Andalusian author Ibn al-Sīd al-Batalyawsī, although this attribution is sometimes contested. This paper offers a new interpretation of the title, textual history, authorship, sources, and literary genre of this treatise, on the basis of new textual evidence, a reexamination of known evidence, and a comparison between the treatise and Batalyawsī’s works. The conclusions of this study are first, that Kitāb al-ḥadā’iq was not the treatise’s original title, and therefore it should be renamed Kitāb al-dawā’ir; second, that Kitāb al-dawā’ir was originally part of (one of the versions of Batalyawsī’s Kitāb al-masā’il; and third, that the textual and stylistic similarities between this treatise and Batalyawsī’s other works prove the authenticity of the treatise’s attribution to Batalyawsī. In addition, new findings regarding Batalyawsī’s use of formulas from the Rasā’il Ikhwān al-Safā, in Kitāb al-dawā’ir and Kitāb al-masā’il provide further evidence for the deep impact of the Ikhwān on Batalyawsī’s thought, as well as for the close connection between Kitāb al-dawā’ir and Kitāb al-masā’il. This connection is further highlighted according to the attribution of both treatises to the genre of questions and answers in Arabic literature. The evidence gathered in this paper supports the claim that Batalyawsī’s Kitāb al-dawā’ir should be seen as an integral part of his literary oeuvre, as well as of Andalusian philosophical literature in general.Generalmente el tratado filosófico conocido como Kitāb al-ḥadā’iq se asocia al autor andalusí del siglo XII Ibn al-Sid al-Batalyawsī, aunque esta atribución ha sido discutida en ocasiones. Este artículo ofrece una nueva interpretación del título, la historia del texto, la autoría, las fuentes e incluso del género literario al que se

Exploring the relationship between caring, love and intimacy in nursing.

Science.gov (United States)

Dowling, Maura

This article uses the five distinct perspectives on caring proposed by Morse et al (1990) to illustrate the relationship between love, intimacy and caring. Two distinct types of love, namely Agape (altruism/charity) and filia (brother love) are utilized in nursing. Only some caring relationships with patients reach an intimate level, and this is determined by patient characteristics to which the nurse responds. It is concluded that caring as a moral imperative is the most relevant to discussions on caring in nursing and the perspective on which the other four viewpoints hinge.

Heteroepitaxial growth of Fe{sub 2}Al{sub 5} inhibition layer in hot-dip galvanizing of an interstitial-free steel

Energy Technology Data Exchange (ETDEWEB)

Wang, Kuang-Kuo [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Chang, Liuwen, E-mail: lwchang@mail.nsysu.edu.t [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Gan, Dershin; Wang, Hung-Ping [Department of Materials and Optoelectronic Science, Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China)

2010-02-01

This work presents characterization results on inhibition layers formed on a TiNb-stabilized interstitial-free steel after short time galvanizing. The Fe-Al and steel interface was free from oxide, so that the Fe-Al intermetallic compound could directly nucleate on ferrite grains. Electron diffraction performed in a transmission electron microscope showed that only Fe{sub 2}Al{sub 5} was formed and it had a well-defined orientation relationship of [110]{sub Fe(sub/2)Al(sub/5)}// [111]{sub Fe}, (001){sub Fe(sub/2)Al(sub/5)}//(011){sub Fe} and (110){sub Fe(sub/2)Al(sub/5)}//(211){sub Fe} with Fe substrate. The structure of the interfaces between Fe{sub 2}Al{sub 5} and Fe is discussed. The epitaxially nucleated Fe{sub 2}Al{sub 5} grains on Fe substrate had very small grain size, 20 nm or less, and several variants were intimately mixed. The grains grew rapidly to hundreds of nanometers toward the Zn side.

The Spanish external quality assessment scheme for lead in blood.

Science.gov (United States)

Marcuello, D

1996-01-01

In 1985 the Instituto Nacional de Seguridad e Higiene en el Trabajo (INSHT) established the "Programa Interlaboratorios de Control de Calidad de Plomo en Sangre (PICC-PbS)". The operation of this scheme is explained, criteria for evaluation of laboratory performance are defined and some results obtained are reviewed.

Development of a TiAl Alloy by Spark Plasma Sintering

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Couret, Alain; Voisin, Thomas; Thomas, Marc; Monchoux, Jean-Philippe

2017-12-01

Spark plasma sintering (SPS) is a consolidated powder metallurgy process for which the powder sintering is achieved through an applied electric current. The present article aims to describe the method we employed to develop a TiAl-based alloy adjusted for this SPS process. Owing to its enhanced mechanical properties, this alloy was found to fully match the industrial specifications for the aeronautic and automotive industries, which require a high strength at high temperature and a reasonably good ductility at room temperature. A step-by-step method was followed for this alloy development. Starting from a basic study on the as-SPSed GE alloy (Ti-48Al-2Cr-2Nb) in which the influence of the microstructure was studied, the microstructure-alloy composition relationships were then investigated to increase the mechanical properties. As a result of this study, we concluded that tungsten had to be the major alloying element to improve the resistance at high temperature and a careful addition of boron would serve the properties at room temperature. Thus, we developed the IRIS alloy (Ti-48Al-2W-0.08B). Its microstructure and mechanical properties are described here.