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Sample records for al desgaste deslizante

  1. Estudio de Algoritmos 2-Deslizantes Aplicados al Control de Pilas de Combustible

    OpenAIRE

    Cristian Kunusch; Paul F. Puleston; Miguel A. Mayosky

    2008-01-01

    Resumen: En este trabajo se hace un estudio comparativo de tres diferentes técnicas de control por modo deslizante de segundo orden, aplicadas al problema específico del control de respiración de una pila de combustible PEM. Los algoritmos diseñados se contrastan por simulación utilizando el modelo completo del sistema, poniendo particular énfasis en la respuesta transitoria y la robustez frente a perturbaciones. Palabras clave: Pilas de Combustible, Control no lineal, Modo Deslizante

  2. Estudio de Algoritmos 2-Deslizantes Aplicados al Control de Pilas de Combustible

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    Cristian Kunusch

    2008-07-01

    Full Text Available Resumen: En este trabajo se hace un estudio comparativo de tres diferentes técnicas de control por modo deslizante de segundo orden, aplicadas al problema específico del control de respiración de una pila de combustible PEM. Los algoritmos diseñados se contrastan por simulación utilizando el modelo completo del sistema, poniendo particular énfasis en la respuesta transitoria y la robustez frente a perturbaciones. Palabras clave: Pilas de Combustible, Control no lineal, Modo Deslizante

  3. Mecanismos de desgaste en refractarios de colada continua asociados al efecto Marangoni

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    Brandaleze, E.

    2005-12-01

    Full Text Available Nozzle wear during continuous casting process is caused by physical and chemical reasons and also by refractory quality. A post mortem study on a sample of Al2O3 - graphite nozzle with a ZrO2 insert allows to identify the present wear mechanisms. Different cyclic stages are carried out due to recurrent changes of interfacial tension and fluid convection. When the surface tension promote the refractory wetting by the steel, graphite of the nozzle surface is lost. Then, grains of ZrO2 and of Al2O3 are dissolved by slag contact. This type of wear is associated with the Marangoni effect. Light and electronic microscopy was used to observe the refractory structure and by a cathodoluminiscence technique phases transformations under process conditions are determined.

    Las buzas sumergidas se erosionan durante el proceso de la colada continua, debido a causas físicas, químicas y a la calidad del refractario. El estudio post mortem de una buza de Al2O3 -grafito con inserto de ZrO2 permite identificar los mecanismos de desgaste presentes, que ocurren por etapas debido a cambios cíclicos de tensión interfacial y convección de fluidos. Cuando la tensión superficial favorece la mojabilidad del refractario por el acero, la buza pierde grafito de la superficie. Luego, los granos de ZrO2 y de Al2O3 se disuelven al ser mojados por la escoria. Este desgaste está asociado al efecto Marangoni. Se observa la microestructura mediante microscopía óptica y electrónica y, por catodoluminiscencia, se determinan las transformaciones de fases ocurridas en condiciones de proceso.

  4. EFECTO DEL PRECALENTAMIENTO Y LA SEVERIDAD DE TEMPLE SOBRE LA RESISTENCIA AL DESGASTE ADHESIVO DEL ACERO AUSTENÍTICO AL MANGANESO

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    OSCAR FABIÁN HIGUERA COBOS

    2010-01-01

    Full Text Available En este trabajo de investigación se estudió el efecto del precalentamiento y la severidad de temple sobre la resistencia al desgaste adhesivo del acero austenítico al manganeso ASTM A 128 grado C. El material se sometió a ciclos térmicos de temple y revenido con y sin precalentamiento con el fin de evaluar su influencia sobre la resistencia al desgaste. Posteriormente el material fue sometido a prueba según norma ASTM G83 y se determinó que el acero Austenítico al manganeso, es un material que presenta una microestructura metaestable en condiciones estables y no debe ser sometido a tratamiento térmico de revenido a altas temperaturas debido que favorece la descomposición de esta a ferrita (fase blanda de los acero y por ende disminuye su resistencia al desgaste.

  5. Propiedades mecánicas bajo compresión y resistencia al desgaste abrasivo de piezas gruesas de caucho acrilonitrilo

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    Sandra Milena Velásquez-Restrepo

    2015-09-01

    Full Text Available Se estudió la variación de las propiedades mecánicas bajo compresión uniaxial y el desgaste abrasivo en la sección transversal de piezas gruesas de caucho acrilonitrilo (NBR reforzadas con negro de humo, teniendo en consideración que en este tipo de piezas las propiedades obtenidas durante la vulcanización no son homogéneas, debido a la baja difusividad térmica de los cauchos. Se realizaron ensayos de desgaste abrasivo en seco, buscando identificar la relación entre la resistencia al desgaste abrasivo y las propiedades mecánicas en compresión, como el módulo elástico y la dureza. Se evaluaron muestras en estado de entrega tras el proceso de vulcanización, luego expuestas al ambiente durante tres meses y, posteriormente, envejecidas en una cámara UV. El envejecimiento ambiental rigidiza los materiales estudiados, pero disminuye la resistencia al desgaste del material proveniente del núcleo de las piezas. El envejecimiento UV disminuyó el módulo elástico, pero su efecto sobre la resistencia al desgaste depende del estado de envejecimiento previo. La dureza no presentó una relación directa ni con el módulo elástico ni con la resistencia al desgaste, por lo cual no puede usarse como propiedad para la selección de cauchos NBR sometidos a desgaste abrasivo. La información obtenida permite generar criterios para el diseño de componentes basados en este tipo de cauchos.

  6. Comportamiento frente al desgaste en materiales compuestos de aluminio reforzados con partículas cerámicas

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    Busquets-Mataix, D.

    2004-04-01

    Full Text Available The present work deals with the wear behaviour on AA6061 based aluminium matrix composites reinforced with different kinds of ceramic particles: TiB2, B4C, Si3N4, Al2O3 y SiC. Composites were obtained by means of a solid-state consolidation method, combining both powder metallurgy processing and hot extrusion. The study carried out was based on a pin-on-ring apparatus under dry sliding conditions (dry friction. Both friction coefficient and wear rate were measured for each composite. Scanning Electron Microscope (SEM was used to analyse wear and the tribolayer formed. Results show that wear rate is lower in composites than in the unreinforced alloy in every case, as expected. Differences among composites are probably related to different particle size rather than nature of reinforcements. On the other hand, friction coefficient do not show a trend on composites, being lower than the base alloy in some cases and higher in others.

    El presente artículo trata sobre las propiedades tribológicas en materiales compuestos de matriz de aleación de aluminio AA6061, reforzados con partículas cerámicas de diferente naturaleza: TiB2, B4C, Si3N4, SiC y Al2O3. Los materiales compuestos fueron obtenidos mediante un procedimiento de consolidación en estado sólido que combina la pulvimetalurgia con un proceso de extrusión en caliente. El estudio tribológico realizado se basó en una metodología de ensayo del tipo pin-on-ring con deslizamiento en seco (sin lubricación. Se analizaron para cada caso el coeficiente de rozamiento y la tasa de desgaste en función de la distancia de deslizamiento. Asimismo, las muestras ensayadas se observaron mediante microscopía electrónica de barrido. Los resultados obtenidos demuestran que las tasas de desgaste de los compuestos son inferiores en todos los casos a los de la matriz sin reforzar. Entre los compuestos, las diferencias encontradas son debidas al tamaño medio de las partículas de refuerzo, obteni

  7. Resistencia al desgaste de recubrimientos Bi/NbC producidos con el sistema sputtering con magnetrón desbalanceado

    OpenAIRE

    Ardila Rodríguez, Laura Angélica

    2013-01-01

    En este trabajo se produjeron películas nano estructuradas de NbC, Bi y bicapas Bi/NbC sobre acero M2 y 316L mediante la técnica Sputtering con magnetrón desbalanceado, y se evaluó su resistencia frente al desgaste por medio del ensayo pin on disc, la adherencia con una prueba de rayado y la resistencia a la corrosión de las películas depositadas sobre los sustratos 316L mediante técnicas electroquímicas. La microestructura de los recubrimientos se analizó mediante Difracción de rayos X, M...

  8. INFLUENCIA DE LOS RECUBRIMIENTOS DÚPLEX SOBRE LAS PROPIEDADES MECÁNICAS Y RESISTENCIA AL DESGASTE DEL ACERO AISI 4140 BONIFICADO

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    Francisco Javier Bolívar Osorio

    Full Text Available El acero AISI 4140 es un acero de baja aleación al cromo/molibdeno de elevada resistencia mecánica y buena tenacidad, el cual se utiliza para la fabricación de piezas de maquinaria como piñones, cigüeñales, ejes de levas, etc. Sin embargo, su resistencia al desgaste es bastante limitada y suele ser mejorada mediante el tratamiento superficial de la nitruración. El propósito de este trabajo consistió en mejorar las propiedades mecánicas e incrementar la resistencia al desgaste del acero 4140 mediante la aplicación de un tratamiento superficial DUPLEX consistente en la nitruración líquida (conocida como Teniffer seguido del depósito de un recubrimiento duro de nitruro de titanio (TiN. La microestructura cristalina fue evaluada mediante difracción de rayos X, la morfología y la composición química fue determinada por microscopía SEM y espectroscopía de energía dispersiva de rayos X (EDS, las propiedades tribológicas fueron analizadas mediante mediciones en un tribómetro de tipo esfera sobre disco y la microdureza se determinó por el método Vickers. Las muestras tratadas con el recubrimiento dúplex mostraron una resistencia al desgaste 4 veces mayor que la muestra en estado bonificado, lo cual demuestra la aplicación potencial que tiene el acero 4140 sometido a este tratamiento dúplex.

  9. Comportamiento al desgaste por deslizamiento en aceros inoxidables: ferrítico, austenítico, dúplex y martensítico.

    OpenAIRE

    Renedo Rouco, Jordi

    2010-01-01

    En este proyecto se estudia el comportamiento al desgaste por deslizamiento de cuatro aceros representativos de las cuatro grandes familias de aceros inoxidables: ferrítico (AISI 446), austenítico (AISI 316), dúplex (AISI 2205) y martensítico (AISI 420). Para cada uno de ellos se han realizado: caracterización metalográfica, determinación de dureza, densidad y rugosidad, y ensayos de tribología mediante la técnica de bola sobre disco. Esta técnica consiste en deslizar una bola ...

  10. Efecto del tratamiento térmico posterior sobre la resistencia al desgaste por deslizamiento de un recubrimiento base níquel depositado por HVOF

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    Cadenas, P.

    2007-02-01

    Full Text Available In the present research, a nickel base coating was deposited on an AISI 1020 substrate by using high velocity oxy-fuel technique (HVOF. The coating was subsequently post heat -treated by means of an oxyacetylene flame. For the conditions evaluated in the present study, it was found that the CTT coating has 1,15 better wear resistance for the smaller level of the applied load and nearly 50 times for the highest level of the applied load when compared to the STT coatings. These results have been attributed to a better distribution of the hard phases, better cohesion between particles and an increase in hardness, as consequence of the post heat treatment process. A severe wear regime was found for all the samples since the wear rates presented values which were higher than 1·10-5 mm3/m. For the CTT coatings, the wear mechanism was mainly due to the adhesion and oxidation phenomena, meanwhile for the steel counterpart mechanisms such oxidation, grooving and three body abrasion were observed.

    En el presente trabajo, se depositó un recubrimiento base níquel sobre un acero AISI 1020 por la técnica de termorrociado de alta velocidad que utiliza oxígeno como combustible (High Velocity Oxygen Fuel - HVOF y, posteriormente, fue tratado térmicamente mediante llama oxiacetilénica. Para las condiciones evaluadas en este estudio, se encontró que el recubrimiento CTT tiene desde 1,15 veces más resistencia al desgaste, para el menor nivel de carga aplicada y mayor velocidad de deslizamiento y, hasta 50 veces más resistencia al desgaste para el mayor nivel carga aplicada y mayor velocidad de deslizamiento, comparado con el recubrimiento STT. Estos resultados se atribuyeron a una mejor distribución de las fases endurecedoras, una mejor cohesión entre partículas y un aumento en la microdureza del recubrimiento, como consecuencia del tratamiento térmico posterior. El régimen de desgaste presente en todas las muestras fue severo, ya que las

  11. Resistencia al desgaste de recubrimientos de bronce al aluminio producidos con técnica de proyección térmica//Wear resistance of aluminum bronze coatings produced by thermal spray

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    Dayan Carolina Cárdenas-Feria

    2015-09-01

    Full Text Available Se estudió la resistencia al desgaste adhesivo de recubrimientos de bronce al aluminio depositados con la técnica de proyección térmica por llama sobre bronce fosforado SAE 62. Los recubrimientos fueron fabricados variando las presiones parciales de los gases de combustión, oxígeno y acetileno. El material utilizado fue caracterizado estructuralmente mediante difracción de rayosX (X-ray diffraction, XRD y el estudio morfológico mediante microscopía electrónica de barrido (Scanning electron microscopy, SEM. La resistencia al desgaste adhesivo de los recubrimientos se determinó por medio del ensayo de bola sobre disco, utilizando como bola una esférica de acero 100Cr6. Los resultados obtenidos permiten establecer que los recubrimientos proyectados con una presión de oxigeno de 78 psi y una presión de acetileno de 8 psi presentan la mejor resistencia al desgaste en comparación a los tratamientos producidos. El modo de falla de desgaste en los recubrimientos producidos es discutido en esta investigación.Palabras clave: desgaste abrasivo y adhesivo,  proyección térmica,  recubrimientos.______________________________________________________________________________AbstractWe studied the adhesive wear resistance of aluminum bronze coatings deposited by thermal spray on phosphor bronze SAE 62 substrates. The coatings were deposited by varying the partial pressures of the combustion gases: oxygen and acetylene. The structural characterization was made through X-ray diffraction (XRD and the morphological analysis was performed by scanning electron microscopy (SEM. The adhesive wear resistance of the coatings was determined by the bole on disc test using a spherical ball made of steel 100Cr6 and with a diameter of 6 mm. The results obtained show that the coating projected with an oxygen pressure of 78 psi and an acetylene pressure of 8 psi have the better wear resistance compared with the substrate and the others treatments deposited

  12. Resistencia al desgaste de recubrimientos Fe-Nb-Cr-W, Nb, AISI 1020 y AISI 420 producidos por proyección térmica por arco eléctrico

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    López-Covaleda, E. A.

    2013-10-01

    Full Text Available The commercial materials 140MXC (with iron, tungsten, chrome, niobium, 530AS (AISI 1015 steel and 560AS (AISI 420 steel on AISI 4340 steel were deposited using thermal spray with arc. The aim of work was to evaluate the best strategy abrasive wear resistance of the system coating-substrate using the following combinations: (1 homogeneous coatings and (2 coatings depositing simultaneously 140MXC + 530AS and 140MXC + 560AS. The coatings microstructure was characterized using Optical microscopy, Scanning electron microscopy and Laser confocal microscopy. The wear resistance was evaluated through dry sand rubber wheel test (DSRW. We found that the wear resistance depends on the quantity of defects and the mechanical properties like hardness. For example, the softer coatings have the biggest wear rates and the failure mode was characterized by plastic deformation caused by particles indentation, and the other hand the failure mode at the harder materials was grooving. The details and wear mechanism of the coatings produced are described in this investigation.Mediante proyección térmica de arco eléctrico fueron depositados tres materiales comercialmente conocidos como: 140MXC (a base de hierro, wolframio, cromo y niobio, 530AS (acero AISI 1020 y 560AS (acero AISI 420, sobre acero AISI 4340. Con el objetivo de evaluar la mejor estrategia para incrementar la resistencia al desgaste abrasivo, los recubrimientos fueron depositados de dos formas: (1 monocapas homogéneas de cada material y (2 recubrimientos depositando con alambres disimiles de 140MXC + 530AS y 140MXC + 560AS. Los recubrimientos fueron caracterizados microestructuralmente mediante Difracción de rayos X, Microscopía óptica, Microscopía láser confocal y Microscopía electrónica de barrido. La evaluación de la resistencia al desgaste abrasivo se realizó mediante ensayo con arena seca y rueda de caucho (DSRW. Se encontró que la resistencia al desgaste depende entre otras de las

  13. Influencia del contenido de silicio y el tratamiento térmico en la resistencia al desgaste de fundiciones blancas al cromo en condiciones de rápida solidificación

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    Goyos, L.

    2012-08-01

    Full Text Available The influence of silicon content and heat treatment on microstructure, abrasive and dry friction wear resistance of a 3 % C, 12 % Cr cast iron, under fast solidification conditions is studied. The fast solidification condition diminishes the carbide volume and the silicon content increases their dispersion and finesses. All matrixes obtained were perlitics, whit different finesses. No intermediate transformation products were noticed. Hardness had little variation. Austenization treatment show little affectivity, with tendency to increase wear in reference to as cast and maintenance treatments. Behavior under dry friction and abrasive wear were similar under test conditions applied whit more influence of carbide morphology in the abrasive wear conditions.

    Se estudia la influencia del silicio y el tratamiento térmico sobre la microestructura y la resistencia al desgaste abrasivo y por fricción seca de una fundición con 3 % C y 12 % Cr, obtenida en condiciones de rápida solidificación. La rápida solidificación disminuye el volumen de carburos, la finura y dispersión de éstos aumentan con el incremento del silicio. Todas las muestras presentaron matrices perlíticas, variando en finura con el tratamiento. No se apreciaron productos de transformación intermedios. Las durezas tuvieron poca variación. Los tratamientos de austenización mostraron poca efectividad, con tendencia a desgastes más elevados que en estado bruto de colada y con tratamiento de mantenimiento. Los comportamientos ante la abrasión y la fricción seca en las condiciones ensayadas fueron similares. Se evidenció alta influencia de la morfología de los carburos en el desgaste abrasivo.

  14. Efecto del porcentaje de refuerzo frente al desgaste en compuestos de matriz metálica sinterizados con descarga luminiscente anormal

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    Pérez-Velásquez, Sandra

    2016-03-01

    – N2 y tiempo de permanencia de 30 minutos. De acuerdo a los resultados obtenidos se concluye que la mejor condición de fabricación de los MMC, se consigue cuando la mezcla contiene 6% de TiC, alcanzando el menor tamaño de grano, la mayor dureza y el más bajo coeficiente de fricción. En este sentido, se observó que la incorporación de partículas de cerámica (TiC en matriz de acero austenítico (316 presentan mejoras significativas en la resistencia al desgaste.

  15. Relación microestructura resistencia al desgaste de recubrimientos duros ricos en cromo y tungsteno aplicados por soldadura electrica (SMAW

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    Lisys Margarita León Sevilla

    2004-01-01

    Full Text Available Se comparó la microestructura y resistencia a la abrasión de recubrimientos duros depositados por soldadura sobre placas de acero estructural ASTM A36. Se utilizaron cinco electrodos comerciales, dos de bajo cromo, dos de alto cromo aplicados en una y dos capas y uno rico en tungsteno depositado en una capa La resistencia al desgaste fue evaluada en una máquina de rueda de caucho y arena seca construida según la norma ASTM G65-80. Como material abrasivo se utilizaron partículas de sílice con índice de finura AFS 50- 70. La caracterización de las microestructuras se realizó utilizando microscopía óptica y electrónica de barrido. Los resultados mostraron que el parámetro de resistencia a la abrasión no está directamente relacionado con dureza del material pero sí con el tipo, tamaño, forma, composición química y distribución de los carburos presentes en la matriz del recubrimiento. La mejor resistencia a la abrasión se obtuvo en depósitos con microestructura compuesta por carburos primarios (del tipo M7C3 en recubrimientos ricos en Cr o del tipo MC, M6C en recubrimientos ricos en W en una matriz eutéctica.

  16. UN NUEVO ENFOQUE DEL CONTROL POR MODO DESLIZANTE PARA SISTEMAS MULTIVARIABLES

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    Rafael Angel Orellana Prato

    2016-09-01

    Full Text Available Este trabajo presenta el diseño de un sistema de control por modo deslizante (SMCr basado en alimentación adelantada (feedforward aplicado a un sistema multivariable, sintonizado para especificaciones de la respuesta transitoria, usando modelos de primer orden más tiempo muerto (POMTM. Como caso de estudio se presenta el modelo multivariable de dos entradas y dos salidas de una columna de destilación Wood and Berry, la cual presenta un alto índice de interacción. Las pruebas demostraron que la estrategia de control propuesta mejora el desempeño de un sistema de control multivariable ante cambios en los valores de referencia y rechazo a las perturbaciones, sin embargo, el tiempo de establecimiento de las variables controladas aumenta producto de dinámica considerada en el desacoplamiento. Se comprobó que en sistemas con alta interacción las señales de control tienen cambios más suaves lo que indica menor desgaste en los elementos finales de control.

  17. Factores asociados al desgaste profesional en los trabajadores del soporte vital básico del País Vasco: Un estudio cualitativo

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    Sendoa Ballesteros Peña

    Full Text Available Objetivos: Identificar factores de riesgo de desgaste profesional percibidos por los técnicos en emergencias sanitarias de las unidades de soporte vital básico del País Vasco. Metodología: Investigación cualitativa realizada mediante análisis de discurso en ocho entrevistas individuales a trabajadores del soporte vital básico con puntuaciones compatibles con afectación por desgaste profesional en el Inventario de Burnout de Maslach. Las variables estructurales tenidas en cuenta para la elección de los participantes fueron la antigüedad profesional (superior o inferior a 10 años y el centro de trabajo. Resultados: Los trabajadores presentan disconformidad con la actual estructura organizacional del sistema de emergencias y falta de proyección y reconocimiento de su rol profesional. Además manifiestan un progresivo distanciamiento afectivo para con los pacientes, con quienes ha aumentado el número de enfrentamientos debidos a dificultades de entendimiento causadas por situaciones de inadecuación del uso de los recursos asistenciales. Conclusiones: La estructura de organización del sistema de emergencias, el trato con el paciente y su familia y la situación profesional del técnico en emergencias son percibidos como elementos clave predisponentes de desgaste profesional.

  18. Resistencia al desgaste de recubrimientos sol-gel de SiO2 y SiO2 - ZrO2 sobre materiales vitrocerámicos obtenidos por sinterización

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    Soares, V. O.

    2013-10-01

    Full Text Available The sol-gel process is widely used to obtain coatings on glass-ceramic substrates in order to improve the scratch and abrasion resistance, also providing a bright and homogeneous appearance of a glaze avoiding expensive final polishing treatments. This paper describes the preparation of silica and silica / zirconia coatings by sol-gel method on Li2O-Al2O3-SiO2 (LAS glassceramic substrates produced by sintering. The coatings were deposited by dip-coating on LAS substrates and characterized by optical microscopy and spectral ellipsometry. On the other hand, hardness and elastic modulus, coefficient of friction and abrasion and scratch resistance of the coatings were determined and compared with the substrate properties. Coatings deposited on LAS glass-ceramic confere the substrate a bright and homogeneous aspect, similar to a glaze, improving the appearance and avoiding the final polishing. However these coatings do not increase the scratch resistance of the substrate only equaling the properties of the glass-ceramic.El proceso sol-gel es un método interesante para la producción de recubrimientos vítreos sobre sustratos vitrocerámicos con el fin de mejorar su resistencia al rayado y al desgaste, y proporcionando además un aspecto homogéneo, vidriado y brillante que evite los costosos tratamientos finales de pulido. Este trabajo describe la preparación de recubrimientos de sílice y sílice/ circona por el método sol-gel sobre sustratos vitrocerámicos del sistema Li2O-Al2O3-SiO2 (LAS producidos por sinterización. Los recubrimientos se depositaron por la técnica de inmersión y se caracterizaron mediante microscopía óptica de luz reflejada y elipsometría espectral. Por otro lado, se determinó la dureza y el módulo de elasticidad, además del coeficiente de fricción, la resistencia al desgaste y al rayado de los recubrimientos. Estos resultados se compararon con las propiedades del sustrato sin recubrir. Las capas depositadas

  19. Recubrimientos de materiales compuestos metal-cerámico obtenidos por nuevas tecnologías de proyección térmica: Proyección fría (CGS y su resistencia al desgaste

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    Miguel, J. M.

    2011-10-01

    Full Text Available In this paper, composite coatings composed by an aluminum bronze metal matrix and a hard ceramic alumina phase obtained by cold spray technique were obtained in order to increase the tribological properties of the pure bronze coatings. The different processes that occur during the coating formation (hardening of the metal particles, fragmentation of the ceramic particles, shot peening on the metal substrate, etc are described and their effects on the coating properties are studied. Wear tests consisting on Ball-on-Disk tests, abrasion Rubber Wheel tests and erosion tests as well as microhardness and adhesion tests are carried out and the results are correlated with the ceramic phase content of the coatings. It can be concluded that the hard ceramic phase increases the tribological properties with relation of the initial bronze coating. Finally, main wear mechanisms during the tribological tests are described. Keywords

    En este artículo se utiliza la técnica de proyección fría (Cold Gas Spray -CGS- para la obtención y caracterización de materiales compuestos constituidos por una matriz metálica de bronce de aluminio y una fase cerámica de alúmina con la intención de mejorar la resistencia al desgaste de los recubrimientos de bronce metálico puros. Se describen los diferentes procesos que ocurren durante la formación del recubrimiento (acritud de las partículas metálicas, rotura de las partículas cerámicas, efecto de granallado sobre el substrato metálico, entre otros y se analizan cuáles son sus consecuencias sobre las propiedades del recubrimiento. Se han realizado ensayos de desgaste por fricción (ensayo Ball-on-Disk, abrasión (Rubber Wheel y erosión, así como se ha determinado la microdureza y adherencia, y correlacionando los resultados obtenidos con el contenido de fase cerámica del recubrimiento. Se concluye que la fase cerámica reforzante incrementa sustancialmente las propiedades tribológicas con relaci

  20. RESISTENCIA AL DESGASTE EROSIVO-CORROSIVO DE ACEROS AUSTENÍTICOS FERMANAL RESISTÊNCIA AO DESGASTE EROSIVO-CORROSIVO DE AÇOS AUSTENÍTICOS FERMANAL EROSIVE-CORROSIVE WEAR RESISTANCE OF FERMANAL AUSTENITIC STEELS

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    Willian Aperador

    2012-12-01

    Full Text Available Se obtuvieron aleaciones austeníticas del sistema Fe-Mn-Al, en el intervalo Fe-(4,9~11,0 wt% de Al-(17,49~34,3 wt% de Mn-(0,43~1,25 wt% de C, las cuales fueron fundidas en un horno de inducción a partir de materiales de alta pureza. Las aleaciones se evaluaron con respecto a fenómenos de corrosión, erosión en medio húmedo y corrosión-erosión, a un ángulo de impacto de 90º. Para la evaluación de la corrosión se empleó una solución compuesta por 0,5 M de NaCl y partículas de sílice con tamaño entre 210 y 300 µm, con el fin de analizar el efecto del contenido de manganeso y aluminio en la resistencia a la erosión y a la corrosión-erosión de estas aleaciones. Para la caracterización de la respuesta corrosiva se usó la técnica con curvas de polarización potenciodin ámicas y la extrapolación de Tafel, la caracterización microestructural mediante microscopia electrónica de barrido (MEB y los productos de corrosión a través de difracción de rayos X (DRX.Obtiveram-se ligas austeníticas do sistema Fe-Mn-Al, no intervalo Fe-(4,9~11.0 wt% de Al-(17,49~34.3 wt% de Mn-(0, 43~1.25 wt% de C, as quais foram fundidas em um forno de indução a partir de materiais de alta pureza. As ligas avaliaram-se com respeito a fenômenos de corrosão, erosão em médio úmido e corrosão-erosão, a um ângulo de impacto de 90º. Para a avaliação da corrosão empregou-se uma solução composta por 0,5 M de NaCl e partículas de sílice com tamanho entre 210 e 300 µm, com o fim de analisar o efeito do conteúdo de manganês e alumínio na resistência à erosão e à corrosão-erosão destas ligas. Para a caracterização da resposta corrosiva usou-se a técnica com curvas de polarização potenciodinâmicas, a extrapolação de Tafel, a caracteriza ção microestructural mediante microscopia eletrônica de varredura (MEV e os produtos de corrosão através de difração de raios X (DRX.We obtained austenitic alloys of the Fe-Mn-Al, Fe in

  1. Avaliação da resistência ao desgaste de aluminas nanométricas produzidas a partir da decomposição térmica de acetato de alumínio liofilizado Evaluation of wear resistance of nanometric aluminas produced by thermal decomposition of lyophilized aluminum acetate

    Directory of Open Access Journals (Sweden)

    E. Fagury Neto

    2007-12-01

    Full Text Available Ensaios de resistência ao desgaste, na modalidade pino-contra-disco com pares deslizantes, foram realizados em pinos confeccionados a partir de pós de alumina proveniente do processo de decomposição térmica de acetato de alumínio liofilizado. Pós de alumina referentes às fases alfa-Al2O3 e gama-Al2O3, com e sem aditivos de sinterização (MgO e La2O3, foram usados para confeccionar pinos de desgaste. Pinos feitos também a partir de alumina comercial (A1000 SG foram analisados e os resultados foram comparados. Os ensaios foram feitos de acordo com norma ASTM e mostraram que os pinos confeccionados a partir de alfa-Al2O3 têm elevada resistência ao desgaste, comprovada pelos ensaios de perda de massa e microscopia eletrônica. Os pinos de gama-Al2O3 tiveram desempenho intermediário e os pinos de A1000 SG mostraram resultados menos expressivos.Wear resistance tests, using the pin-on-disk test method with sliding pairs, were carried out on pins produced from alumina powders prepared by thermal decomposition of lyophilized aluminum acetate. Alumina powders of alpha-Al2O3 and gamma-Al2O3 phases, with and without sintering additives (MgO and La2O3, were used to produce wear pins. In addition, pins made of commercial alumina (A1000 SG were tested and the results compared. The tests, carried out according to the ASTM standard, indicated that the pins made with alpha-Al2O3 powder showed high wear resistance, a finding corroborated by mass loss tests and scanning electron microscopy. The gamma-Al2O3 pins showed an intermediary performance while the A1000 SG pins showed less interesting results.

  2. Influencia de los tratamientos térmicos en el comportamiento frente al desgaste por abrasión de una fundición de grafito esferoidal obtenida mediante adición de boro

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    Varela, A.

    2008-08-01

    Full Text Available By adding boron to the liquid metal, it is possible to obtain spheroidal graphite cast iron without any need for special inoculants. The boron may be in metallic form; alternatively, borax, ferroboron, boron carbonate or borocalcium can be used. These alloys as cast present a pearlite matrix with more or less spheroidal graphite, which is usually edged in ferrite that has markings in the shape of bull’s eye. With normalising, the ferrite edges are eliminated. Thus, a pearlite matrix is achieved. Annealing results in an entirely ferrite matrix; quenching and tempering produce a tempered martensite matrix.This study measures the behaviour under wear of this alloy as cast, normalised, annealed, quenched and tempered . A “pin on disk” test is employed; load and speed conditions, as well as the pin type, are kept constant. Moreover, wear is calculated through weighing, and the variation for the friction coefficient is determined in each case.

    Mediante la adición de boro al metal líquido, bien en forma metálica o en forma de bórax, ferroboro, carburo de boro o boruro cálcico, se pueden obtener fundiciones de grafito esferoidal sin necesidad de inoculantes especiales. Estas fundiciones en estado bruto de colada presentan una matriz perlítica con grafito más o menos esferoidal que suele estar orlado de ferrita formando ojos de buey. Por tratamiento térmico de normalizado, se consigue eliminar la orla ferrítica y tener una matriz enteramente perlítica. Por recocido, se puede obtener una matriz enteramente ferrítica y por temple y revenido una matriz de martensita revenida. En el presente trabajo se mide el comportamiento frente al desgaste abrasivo de la aleación indicada, en estado bruto de colada, normalizado, recocido y bonificado, utilizando el ensayo pin on disk, manteniendo fijas las condiciones de ensayo en cuanto a carga, velocidad y tipo de pin, calculando el desgaste producido por pesada. También, se

  3. Control por Modos Deslizantes y Planitud Diferencial de un Convertidor de CD/CD Boost: Resultados Experimentales

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    R. Silva-Ortigoza

    2008-10-01

    Full Text Available Resumen: En este trabajo se presenta el control del convertidor de potencia de CD a CD Boost. En este sistema existen dos problemas de control, a saber; la regulación alrededor de un punto de equilibrio y la de seguimiento de trayectoria del voltaje de salida. Nosotros enfocamos nuestra atención al segundo problema de control. Debido a las propiedades de fase que satisface este convertidor, para realizar la tarea de seguimiento de trayectoria se diseña un controlador indirecto basado en modos deslizantes en combinación con planitud diferencial, el cual permite el seguimiento de trayectoria de la variable de fase no mínima (voltaje basado en el seguimiento de trayectoria de la variable de fase mínima (corriente. La síntesis de este controlador se realiza con la ayuda de una tarjeta de adquisición de datos National Instruments™ PCI-6025E junto con el software de aplicación MATLAB®-Simulink®. Se aplica este controlador al prototipo del convertidor Boost desarrollado y se obtienen resultados experimentales satisfactorios. Palabras clave: Control Indirecto, Convertidor de CD/CD Boost, Modos Deslizantes, Planitud Diferencial, Seguimiento de Trayectoria

  4. Desarrollo y optimización de recubrimientos de superaleaciones con adición de cargas cerámicas y elementos reactivos obtenidos por proyección térmica para aplicaciones de resistencia a oxidación a alta temperatura y al desgaste

    OpenAIRE

    Cervera González, Iván

    2011-01-01

    El objetivo principal del presente trabajo es la obtención de recubrimientos con una composición optimizada para aplicaciones de elevada resistencia a alta temperatura y al desgaste, proyectados térmicamente sobre acero al carbono AISI 1110, mediante la técnica de oxifuel, basados en el sistema NiCrAlY/Al2O3. Estos recubrimientos deben ser capaces de proteger adecuadamente a un material de escasa resistencia mecánica y térmica para el rango de temperaturas analizado, que se sitúa entre 850 – ...

  5. EFECTO DEL CONTENIDO DE CARBONO SOBRE LA RESISTENCIA AL DESGASTE ABRASIVO DE RECUBRIMIENTOS DE CrC DEPOSITADOS POR PULVERIZACIÓN CATÓDICA MAGNETRÓN EFEITO DO CONTEÚDO DE CARBONO SOBRE A RESISTÊNCIA AO DESGASTE ABRASIVO DE RECOBRIMENTOS DE CrC DEPOSITADOS POR PULVERIZAÇÃO CATÓDICA MAGNETRÃO EFFECT OF THE CARBON CONTENT IN ABRASIVE WEAR RESISTANCE OF CrC COATINGS DEPOSITED BY MAGNETRON SPUTTERING

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    Maryory Astrid Gómez

    2012-12-01

    Full Text Available Los recubrimientos de carburo de cromo sobre acero son un buen candidato para aplicaciones de conformado y moldes de inyección. La alta resistencia mecánica, resistencia química y estabilidad a alta temperatura de la fase Cr3C2 pueden ser compatibles con el intenso desgaste abrasivo y la corrosión en tales operaciones de fabricación. En este trabajo se depositaron recubrimientos de CrC por pulverización catódica magnetrón RF, los cuales mostraron contenidos de carbono entre el 25 % y el 58 % por análisis EDS. Los valores de dureza de estos recubrimientos fueron entre 15 y 24 GPa; los más duros de las muestras tuvieron contenido de carbono en el rango de 39-53 %. El desgaste abrasivo de los recubrimientos se evaluó utilizando un equipo de disco abrasivo con polvo de diamante. El volumen de las huellas de abrasión se midió con las imágenes obtenidas en el microscopio interferométrico y además se corroboró con el cálculo del volumen geométrico basado en secciones medidas con el perfilómetro. El comportamiento al desgaste abrasivo mostró una marcada dependencia con el contenido de carbono. El desgaste abrasivo más bajo se obtuvo para los recubrimientos con el más alto contenido de carbono.Os recobrimentos de carburo de cromo sobre aço são um bom candidato para aplicações de conformado e moldes de injeção. A alta resistência mecânica, resistência química e estabilidade em alta temperatura da fase Cr3C2 podem ser compatíveis com o intenso desgaste abrasivo e a corrosão em tais operações de fabricação. Neste trabalho depositaram-se recobrimentos de CrC por pulverização catódica magnetrão RF, os quais mostraram conteúdos de carbono entre 25 % e 58 % por análise EDS. Os valores de dureza destes recobrimentos foram entre 15 e 24 GPa; os mais duros das mostras tiveram conteúdo de carbono na faixa de 39-53 %. O desgaste abrasivo dos recobrimentos avaliou-se utilizando uma equipe de disco abrasivo com pó de

  6. Efecto del conteo de nódulos en la resistencia al desgaste por abrasión de los hierros dúctiles austemperados

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    C. J. Diez Cicero

    2009-05-01

    Full Text Available Entre los materiales metálicos de mayor demanda, la producción de hierro con grafito nodular, ocupa en la actualidad, uno de los lugares más importantes entre los hierros fundidos de alta resistencia, y con la introducción del tratamiento térmico de austemperado, aplicado a estas fundiciones, se da lugar a una nueva familia de materiales, caracterizados por su alta resistencia mecánica y elevada tenacidad, que mantienen la economía y facilidad de producción de las fundiciones nodulares.Este trabajo, hace una valoración del comportamiento de hierros nodulares, con diferentes conteos de nódulos, a los que les fue aplicado el tratamiento de austemperado, y posteriormente se les sometió a ensayos de desgaste abrasivo. Con los resultados obtenidos, se hace un análisis de la influencia del conteo de nódulos en dichas propiedades, así como también, de la interrelación del conteo de nódulos, con las variables de tratamiento térmico utilizadas en las muestras ensayadas.Between the metallic materials of greater demand, the iron production with nódular graphite occupies at the present time, one of the most important places between fused irons of high resistance, and with the introduction of the austemperado heat treatment of, applied to these smeltings, gives rise to a new family of materials, characterized by its high resistance mechanical and elevated tenacity, that the economy and facility of production of the smeltings maintain nodulares. This work, makes a valuation of the iron behavior nodulares, with different counts from nodules, to which the austemperado was applied treatment to them of, and later it was put under to them tests of abrasive wearing down. Of the obtained results, an analysis takes control of the influence of the count of nodules in these properties, as well as, of the interrelation of the count of nodules, with the used variables of heat treatment in the tried samples.

  7. Estabilidad para un control borroso en modo deslizante aplicado a un robot paralelo neumático

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    Pablo J. Prieto

    2015-10-01

    Full Text Available Resumen: Se presenta un controlador borroso tipo Mamdani basado en técnicas en modo deslizante para el posicionamiento de un robot paralelo neumático de dos grados de libertad (2 GDL. Es probado que el sistema es asintóticamente estable en el sentido de Lyapunov y se presentan resultados numéricos y experimentales. Ma's aún, el controlador diseñado puede ser aplicado en control de trayectoria al ser retroalimentadas la velocidad y la aceleración del sistema. Se presentan adema's resultados satisfactorios obtenidos en forma experimental para el caso de seguimiento de trayectoria. Abstract: In this paper is reported a Mamdani type fuzzy controller based on sliding mode techniques applied to the regulation of a 2 DOF pneumatic parallel robot. Is is proved that the system is stable in Lyapunov sense, and numerical and experimental results are reported. Moreover, the designed controller can be applied to tracking control if speed and acceleration from the system are feedbacked. Also are reported satisfactory experimental results for the tracking case. Palabras clave: Control borroso, Control de robot, Estabilidad de Lyapunov, Modos deslizantes., Keywords: Fuzzy control, Robot control, Lyapunov stability, Sliding mode.

  8. Comportamiento frente al desgaste y fricción de aceros empleados en líneas de manutención aérea ensayados con y sin lubricación

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    Castro Regal, G.

    2005-06-01

    Full Text Available The sliding friction and wear behaviour of different steel qualities were investigated with and without lubrication conditions. Steel qualities tested are normally used in the overhead conveyor system of many industrial fields, like the automotive sector. Sliding wear tests have been conducted by means of a pin-on-disk machine. A 100Cr6 steel similar to that used within the overhead conveyor trolleys has been employed as a pin. Friction coefficient values obtained under lubrication conditions were three times smaller than those obtained without lubrication. The mechanism that controls wear behaviour under lubrication conditions is an abrasive one and the wear values obtained are almost worthless. On the other hand, mechanism controlling wear during non lubrication tests, was a combination of abrasion and adhesion

    Se ha evaluado el comportamiento frente a fricción y el desgaste de distintas calidades de acero ensayadas bajo condiciones de lubricación y sin lubricación. Las calidades de acero seleccionadas son las que normalmente se emplean en los sistemas de manutención aérea de numerosos procesos de producción, como la fabricación de automóviles. Se han realizado ensayos de desgaste tipo punzón-disco mediante un punzón de acero de calidad100Cr6, empleado en los carros que circulan por las líneas de manutención aérea. Se ha observado que el valor del coeficiente de fricción obtenido bajo condiciones de lubricaciones, aproximadamente, tres veces menor que el obtenido sin lubricación. Por otro lado, el mecanismo que controla el proceso de desgaste de los aceros ensayados con lubricación es un mecanismo de desgaste abrasivo y los valores de desgaste obtenidos son prácticamente despreciables. El desgaste de los aceros ensayados sin lubricación se produjo por combinación de dos mecanismos de desgaste: abrasión y adhesión.

  9. Desgaste por deslizamiento en seco de aceros perlíticos y bainíticos

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    Cristian Camilo Viáfara Arango

    2004-01-01

    Full Text Available El desgaste por deslizamiento tiene una gran influencia sobre el desempeño de los sistemas rueda-riel, en particular, por el deslizamiento de la pestaña de la rueda sobre la parte interna del riel en una pista curva. Dado que el deslizamiento entre la rueda y el riel involucra efectos de adhesión, altos porcentajes de deslizamiento/rodadura afectan fuertemente el desgaste por fatiga de contacto por rodadura, que actúa en las superficies de contacto. En una máquina Pin sobre Disco se llevaron a cabo ensayos de desgaste por deslizamiento para estudiar el comportamiento del acero perlítico AISI 1070 y el bainítico AISI 15B30. La velocidad de deslizamiento fue 1 ms-1 para todas las pruebas y se utilizaron cargas normales de 10, 30 y 50 N. La resistencia al desgaste fue relacionada con la pérdida de masa medida después de las pruebas y las superficies desgastadas, al igual que las partículas removidas, fueron analizadas por medio de los microscopios óptico y electrónico. Se realizaron perfiles de microdureza bajo las superficies de contacto para analizar el efecto del endurecimiento por deformación. El acero perlítico mostró mayor resistencia al desgaste que el acero bainítico, debido al excelente comportamiento de endurecimiento por deformación de la perlita comparado con el de la bainita. En el acero perlítico se observaron regímenes de desgaste oxidativo, mientras que en el bainítico el principal mecanismo de remoción de material fue el adhesivo, llevando a un daño mucho más fuerte en la superficie. De hecho, el régimen de desgaste para las probetas bainíticas fue siempre severo, aún con la menor carga normal aplicada.

  10. Robust control decentralized by sliding ways of electrical of power multi-machines systems; Control robusto descentralizado por modos deslizantes de sistemas electricos de potencia multimaquinas

    Energy Technology Data Exchange (ETDEWEB)

    Huerta Avila, Hector

    2008-09-15

    This work deals with the problem of robust decentralized control of multimachine electric power systems. These systems are subject to different perturbations, such as short circuits, connection and/or disconnection of loads, lines generators, mechanical torque variations, etc. Then, it is necessary controllers which guarantee robustness under those perturbations to provide electrical energy to the loads with admissible stability margins. Moreover, the controller must be robust under parametric variations due to model uncertainties, and other physical reasons. The electrical power systems are modeled as complex great scale nonlinear systems. Then, the controller design is a challenging problem. Thus, the decentralized control schemes enable to avoid these problems. This work proposes three novel robust nonlinear techniques. The first one is based on the block control and integral sliding modes. The second obtains a sliding manifold from the Hamiltonian model of a nonlinear system to use this manifold in the integral sliding modes. The third technique enables to apply the sliding mode technique to a nonlinear block controllable system, by using Lyapunov function in each block. Then, four control schemes for electric power systems are designed. The four control schemes are robust under the perturbations of electric power systems mentioned above. The controllers proposed can be implemented in any electric power system with n generators, m lines and k loads. [Spanish] Este trabajo esta dedicado al diseno de esquemas de control robustos descentralizados que sean capaces de responder satisfactoriamente en sistemas electricos de potencia multimaquinas. Estos sistemas estan sujetos a perturbaciones de diferentes tipos, como cortos circuitos, entrada y salida de lineas de cargas o de generadores. Es evidente la necesidad de controladores que puedan rechazar estas perturbaciones para proveer energia de calidad y sin interrupciones a todos los usuarios conectados a la red

  11. Controlador en Modo Deslizante para Sistemas Fotovoltaicos Conectados a la Red Eléctrica

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    D. Arcos

    2012-11-01

    Full Text Available Se describe el análisis, modelamiento y diseño de un lazo de control para sistemas fotovoltaicos (PV conectados a la red eléctrica. Se aborda el modelado de un panel fotovoltaico; el diseño de un convertidor elevador (Boost y su lazo de control mediante un controlador proporcional-integral PI de corriente y un controlador en modo deslizante; y finalmente el diseño de un inversor DC-AC de una fase. Se realiza una descripción de la dinámica del convertidor Boost y de las ecuaciones para el diseño del controlador en modo deslizante y del inversor de una sola fase. El sistema propuesto ha sido simulado utilizando las herramientas de la librería SimPowerSystems de Matlab/Simulink.

  12. La autoestima como variable moduladora del desgaste profesional en especialistas en Medicina General Integral

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    Lidia Caridad Hernández Gómez

    Full Text Available Introducción: la relevancia otorgada al desgaste profesional (DP como riesgo psicosocial relacionado con el trabajo que afecta la salud del médico, es un hecho creciente, así como sus consecuencias sobre la salud mental, física, la calidad de vida y eficacia de estos profesionales. Igualmente se ha señalado que recursos positivos de la personalidad como la autoestima, pueden ejercer un efecto modulador sobre la aparición del desgaste profesional. Objetivo: identificar la presencia desgaste profesional y su relación con la autoestima en los especialistas en Medicina General Integral. Método: se realizó un estudio descriptivo, de corte transversal, entre enero y junio de 2012. Se seleccionó una muestra de 85 especialistas en Medicina General Integral del municipio Plaza de la Revolución. Se emplearon para el estudio el Cuestionario Breve de Burnout y el de Autoestima (versión para adultos de Cooper-Smith. Resultados: la aplicación de los instrumentos y las pruebas estadísticas permitieron identificar la presencia del DP en los especialistas estudiados, así como la relación que guarda este constructo con la autoestima de los profesionales. Conclusiones. se constató la elevada presencia del desgaste profesional en los especialistas estudiados. Los niveles bajos y medios de autoestima están relacionados con el desgaste profesional y el cansancio emocional en estos especialistas, lo cual apunta a que esta instancia de la personalidad puede modular la aparición del síndrome y sus repercusiones.

  13. Dry sliding wear of Al-Fe-Cr-Mn quasicrystalline phase former alloy obtained by spray forming; Estudo do comportamento ao desgaste de liga Al-Fe-Cr-Mn obtida por conformacao por spray

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, S.M.T.; Rios, C.T.; Botta Filho, W.J.; Bolfarini, C.; Kiminami, C.S. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Gargarella, P.; Mendes, M.A.B., E-mail: marcio.andreato@gmail.co [Universidade Federal de Sao Carlos (PPG-CEMUFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2010-07-01

    Samples from different regions of a spray formed billet of Al{sub 92}Fe{sub 3}Cr{sub 2}Mn{sub 3} quasicrystalline phase former alloy were analyzed and their wear behavior has been studied. The microstructures observed depend on the cooling rate imposed to the material. The border of the billet exhibits a very fine structure with presence of quasicrystalline phase and the base showed a fine structure but without presence of quasicrystalline phase. Dry sliding wear tests were made using three loads and samples of these two different regions. The wear surfaces were analyzed by scanning electron microscopy and X-ray diffraction. Similar wear behavior was observed in the border and the base samples at the same load. The wear mechanism verified is the adhesive and the applied load increases the formation of Al{sub 2}O{sub 3}. These particles can take off the surface and act as abrasive, which can explain the large increase in the wear rate for the samples loaded at 30N.(author)

  14. Estudio del desgaste por deslizamiento en bronces

    OpenAIRE

    Carlos Holguín; John Coronado

    2007-01-01

    Se evaluaron tres bronces: SAE 67, nacional y americano usados típicamente como material de la chumacera en los molinos de caña de azúcar. Se realizaron pruebas desgaste por deslizamiento bajo la norma G77 usando bloques de bronce, anillos de acero SAE 1045 y aceite como lubricante. El tribómetro se calibró usando los anillos de acero SAE 4620 y se usó acero de herramienta SAE O1 para los bloques. Se realizaron metalografías, durezas y rugosidad de los materiales estudiados. El bronce naciona...

  15. Síndrome de Desgaste Emocional en Investigadores Mexicanos

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    Deneb Elí Magaña Medina

    2008-01-01

    Full Text Available El propósito del estudio fue determinar el grado de Síndrome de Desgaste Emocional (burnout en investigadores del estado de Yucatán, México; así como explorar la percepción sobre las condiciones institucionales que pudieran asociarse al mismo. Se administró un cuestionario, que constaba de una escala likert para evaluar las 3 dimensiones del síndrome y una sección de preguntas abiertas al respecto de la institución y su situación laboral, a 109 investigadores. Los resultados muestran ausencia relativa del síndrome, pero tendencia a presentarlo en el periodo de 10 y 20 años de antigüedad. La información cualitativa muestra como factores de estrés laboral la multiplicidad de roles que tienen que asumir, la falta de grupos de trabajo consolidados, de infraestructura administrativa y operativa y los sistemas de evaluación.

  16. Comportamiento del acabado superficial de la pieza y el desgaste de la herramienta al fresar aluminio con altas velocidades de corte en fresadoras cnc convencionales. // Superficial finish behavior and tool wear in aluminium milling with high cutting spee

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    F. Martínez Aneiro

    2006-05-01

    Full Text Available La demanda de componentes mecánicos de alta calidad y gran exactitud para sistemas de elevado desempeño estaaumentando considerablemente en los últimos años a nivel mundial. Este hecho ha provocado el desarrollo de nuevastecnologías aplicadas a los procesos de corte.El desarrollo integral de las máquinas herramientas (controles, husillos de alta velocidad de las herramientas de corte(nuevos materiales para los substratos y capas y de la tecnología de maquinado posibilitó la aplicación del corte con altasvelocidades de corte (High speed Cutting HSC. El aumento de las velocidades de corte es una de las formas de aumentar laeficiencia de los procesos productivos a través de la reducción de los tiempos de fabricación. La reducción en varias vecesde los tiempos de fabricación, se logra no solo por los tiempos de maquinado sino también por la sustitución o minimizarotros procesos de elaboración que forman parte de la cadena productiva, los cuales en ocasiones son relativamente lentoscomo son la electroerosión, el acabado manual en la producción de moldes y troqueles así como los cambios deoperaciones de la pieza.Por ser un proceso relativamente nuevo, introduciéndose a partir de la década de los años 90 aun existen muchas cuestionestecnológicas que están sin respuesta. Es interés del presente trabajo, mostrar los efectos de las altas velocidades de cortesobre la vida útil de la herramienta y el acabado superficial en la pieza, trabajando en máquinas fresadoras de CNC¨convencionales¨. Los resultados muestran que dentro de los parámetros estudiados la durabilidad de la herramienta y elacabado superficial mejoran y que el comportamiento de la máquina es estable a pesar de no estar concebida para el nuevoconcepto de altas velocidades.Palabras Claves: Altas velocidades de corte, HSC, HSM desgaste, acabado superficial.______________________________________________________________________________Abstract.The demand of

  17. Construcción de un pavimento rígido con máquina de encofrado deslizante en la autopista París-Lyon

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    García Meseguer, Álvaro

    1963-12-01

    Full Text Available This article describes the construction of a mass concrete pavement, carried out with the aid of a Gunter-Zimmermann sliding formwork, manufactured in the United States. This device guides itself automatically by means of an electronic control, and does the following set of operations simultaneously: it spreads the concrete over the whole width of the pavement (7.5 ms; vibrates it; shapes it and gives it the final thickness with the aid of the sliding formwork; it provides a longitudinal cut, which serves as a dilation joint; fills this joint with plastic material; places connecting reinforcements across the joint, half way down the depth of the pavement; and smoothes out the final surface. The author refers to the final surface finish; discusses the sawing of the transversal joints, various tests and checks, and the possibilities and limitations of this constructional procedure. He finishes by enumerating some general inferences on this method of road construction.Se describe la ejecución de un pavimento de hormigón en masa con la máquina de encofrado deslizante Gunter-Zimmerman, de fabricación norteamericana. Esta máquina, que se guía automáticamente por medio de contactos electrónicos, realiza, sin solución de continuidad, las siguientes operaciones: reparte el hormigón a todo ancho (7,50 m, lo vibra, le da forma y espesor definitivos en su encofrado deslizante, ejecuta una ranura longitudinal que actúa de junta, rellena esa ranura con una cinta de plástico, introduce unas armaduras de cosido de la junta a medio espesor de la losa e iguala la superficie final. Después de referirse al acabado superficial, al curado, a la ejecución por aserrado de juntas transversales y a diversos ensayos y comprobaciones, analiza el autor las posibilidades y limitaciones de este procedimiento, llegando a las conclusiones que aparecen al final del texto.

  18. Control mediante modos deslizantes en tiempo discreto para el seguimiento de trayectorias de un robot móvil1

    Directory of Open Access Journals (Sweden)

    P.A. Niño-Suárez

    2007-10-01

    Full Text Available Resumen: En este trabajo se presenta una estrategia de control en tiempo discreto para el seguimiento de trayectorias de un robot móvil tipo (2,0 controlado remotamente. La estrategia de control se desarrolló mediante un enfoque de modos deslizantes, considerando el modelo discreto exacto del vehículo en el cual se incluyen los efectos del retardo de transporte causado por la propagación de las señales sobre una red de comunicación. El esquema de control garantiza el seguimiento de trayectorias predeterminadas obteniéndose convergencia asintótica de los errores de seguimiento. La estrategia propuesta es evaluada mediante una serie de resultados por simulación. Palabras clave: Robot móvil, retardos de transporte, control en tiempo discreto, modos deslizantes

  19. Estudio del modelo de desgaste propuesto por Archard

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    FABIO ALEXANDER SUÁREZ BUSTAMANTE

    2005-01-01

    Full Text Available El comportamiento de componentes de máquinas y de materiales necesita ser optimizado para reducir los costos de operación en las plantas industriales. Este hecho ha impulsado la Tribología, un área relacionada con el estudio de la fricción, la lubricación y el desgaste. Uno de los principales objetivos de esta área del conocimiento es elaborar modelos matemáticos para expresar la variación del desgaste durante el contacto de superficies en movimiento, con el fin de predecir la vida útil de los elementos de máquinas. El modelo de Archard para desgaste por deslizamiento en seco, formulado en 1953, es un modelo clásico que plantea una variación del desgaste inversamente proporcional a la dureza del material y directamente proporcional a la carga aplicada. En el presente trabajo, se ha utilizado el método de modelamiento de problemas físicos, propuesto por Asbhy, para analizar los modelos propuestos por Archard (Modelo de contactos múltiples en superficies rugosas y modelo de desgaste mecánico. Con base en él se ha podido realizar un análisis profundo a dichos modelos, mostrando un panorama más amplio del modelo de Archard; se discuten aspectos no mostrados en los textos y artículos de tribología, donde el tratamiento dado a este modelo resulta ser superficial, desconociendo las limitaciones y la perspectiva que tuvo Archard sobre los aspectos que deberían considerarse en un modelo de desgaste.

  20. Desgaste ondulatório em caminhos de ferro

    OpenAIRE

    Martins, Paulo Manuel Caldeira

    2010-01-01

    Trata-se de uma análise técnica completa a um desgaste específico que aparece frequentemente nos sistemas ferroviários, sejam eles comboios (passageiros, carga e alta velocidade), Metropolitanos (ligeiros e pesados) ou mesmo sistemas de carros eléctricos. Anualmente são gastos pelos sistemas ferroviários, consideráveis somas na correcção dos defeitos provocados pelo aparecimento do desgaste ondulatório nos carris de rolamento. Ainda hoje a relativa pouca troca de conhecimentos entre os ...

  1. Predicción del desgaste del flanco de la herramienta de corte durante el torneado en seco de alta velocidad para piezas de acero AISI 316L en la industria minera

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    Yusimit K. Zamora-Hernández

    2015-07-01

    Full Text Available Se realizó un estudio experimental sobre la influencia de los parámetros de corte en el torneado del acero inoxidable AISI 316L con insertos recubiertos de TiCN, Al2O3, TiN. Un microscopio electrónico de barrido fue utilizado para medir y analizar el desgaste de las herramientas de corte. Los resultados fueron comparados utilizando el análisis de varianza y el análisis de regresión múltiple para describir la relación entre el desgaste del flanco de las herramientas de corte, el tiempo de maquinado y el avance de corte, obteniéndose las ecuaciones de los modelos ajustados. La investigación demostró el efecto significativo del avance y del tiempo de maquinado en el desgaste del flanco. El inserto de tres capas no sobrepasó el criterio de fin de vida del desgaste, mientras que el inserto de una capa sufrió un desgaste elevado para la mayor velocidad de corte. El desgaste del flanco tuvo mejor comportamiento para el avance de 0,08 mm/rev en todas las velocidades empleadas en este estudio. Los errores medios absolutos no superaron el 15 %.

  2. Plataforma virtual de péndulo sobre carro deslizante para la enseñanza del control automático

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    Oscar Rodriguez D

    2013-09-01

    Full Text Available En este artículo se presenta el desarrollo de un sistema de plataforma virtual para la enseñanza del control automático basado en el péndulo invertido sobre carro deslizante, el cual se desarrolla herramientas didácticas sobre un prototipo virtual, simulando el modelo no lineal en matlab y presentado en un entorno amigable basado en easy-java. Para el diseño de los controladores, se tienen en cuenta dos aspectos principales como los son el “swing up” (llevar el péndulo a posición vertical y el balanceo (mantener el péndulo en la posición vertical. La interfaz al usuario busca facilitar el aprendizaje de los conceptos básicos de un sistema de control automático para estudiantes de pregrado y posgrado, buscando minimizar costos y tiempo en la enseñanza e implementación de sistemas de control.

  3. DISEÑO E IMPLEMENTACIÓN DE UN CONTROL DUAL POR MODOS DESLIZANTES PARA UN CONVERTIDOR BUCK CD-CA

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    Jaime Ayala Taco

    2015-01-01

    Full Text Available El presente trabajo muestra un análisis orientado a la propuesta de diseño e implementaciónde un doble controlador en modo deslizante para un convertidor Buck CD-CA. Se planteanlas superficies de deslizamiento candidatas de acuerdo con las exigencias de la aplicación y,mediante una lógica de activación de las llaves semiconductoras (MOSFET, se obtiene un controlindependiente en la amplitud de la tensión para el semiciclo positivo y negativo de la onda desalida en CA, con el objetivo de lograr a voluntad un nivel de CD introducido en la señal de alterna.Se ingresan perturbaciones de tensión en la entrada del convertidor y se producen variacionesen la carga con el objetivo de probar la robustez del sistema de control propuesto. El controlse implementa en un microcontrolador AVR Atmega164PA y se prueba de manera práctica.Finalmente, se expone una comparación de los resultados obtenidos de manera experimentalcon las simulaciones realizadas en SCILAB5.

  4. Effects of based Ca O and aluminum ash desulfurization agent on wearing of torpedo car refractories; Acao de agente dessulfurante a base de CaO + Al `ash`sobre o desgaste de refratario de carro torpedo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Sidiney Nascimento; Marques, Oscar Rosa; Delgado, Paulo Roberto Senna [Companhia Siderurgica Nacional, Volta Redonda, RJ (Brazil); Longo, Elson; Varela, Jose Arana [Sao Carlos Univ., SP (Brazil). Dept. de Quimica; Justus, Sergio Murilo [Universidade Estadual de Ponta Grossa, PR (Brazil). Dept. de Engenharia de Materiais

    1996-12-31

    The introduction oa a new desulfurization agent, at Companhia Siderurgica Nacional (CSN) based Ca O and aluminum ash, have been strongly altered the work conditions of slag line refractories of torpedo car. The wearing mechanism of Al{sub 2} O{sub 3}.Si C.C refractories of torpedo car slag line is as follows: graphite and silicon carbide oxidation by the gas present in torpedo car atmosphere and sodium oxide from process slag; as result from these oxidation reactions, there is a increasing of refractory permeability, simultaneously the silica precipitation in the refractory matrix; the refractory matrix, rich in mullite, strongly reacts with the calcium oxide from slag and silica excess, precipitated from oxidation reactions; as consequence, the formation of low melting point phases occurs which accelerates the wearing of material. (author) 12 refs., 6 figs., 8 tabs.

  5. A discreet control of sliding ways of an induction motor; Control discreto de modos deslizantes de un motor de induccion

    Energy Technology Data Exchange (ETDEWEB)

    Rivera Dominguez, Jorge

    2001-12-15

    A control of sliding ways in discreet time for non-linear discreet systems is designed, also the technique of the control by histograms for non-linear discreet systems was developed, and an observer of reduced order was developed for non-linear electromechanical discreet systems. All these techniques are applied to a non-linear discreet model of an induction motor that was found here, that posses electrical and mechanical dynamics, in which the load pair is considered an unknown disturbance. With complete measurements of the states are satisfied the pursuing of the rotor velocity and the amplitude of the magnetic flux of the rotor, where the unknown load does not affect the velocity regulation. Next, an observer of reduced order is implemented where the velocity and current measurements are employed to consider the load pair and the flows that are very difficult to measure. The proposed method has a design and stability procedure of direct analyses, conserving a simple structure of the control law. The simulations predict that the system is robust with respect to several types of load pairs. The responses of velocity and amplitude of the rotor flow and the entrance references evolved very well. These references have a linear dynamics of second order with time constants that can be chosen by the motor user. The practical aspects for a future digital implementation of the control law are considered, including the velocity and currents sensors, the preparation of signals, the transformation of the current in the frame of stationary reference, PWM and inverter modules, which were seen in detail. The experimental results are left as a future work. [Spanish] Se disena un control de modos deslizantes en tiempo discreto para sistemas discretos no lineales, tambien se desarrollo la tecnica del control por bloques para sistemas discretos no lineales, y un observador de orden reducido fue desarrollado para sistemas discretos electromecanicos no lineales. Todas estas tecnicas

  6. Comportamiento a desgaste de recubrimientos de WC proyectados por plasma a partir de polvos micro y nanoestructurados

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    Salvador, M. D.

    2008-06-01

    difracción de rayos X. La caracterización tribológica de los recubrimientos se realiza mediante ensayos pin-on-disc contra bolas cerámicas de alúmina (2.400 HV y nitruro de silicio (1.600 HV, sin lubricación, obteniéndose las tasas de desgaste y la evolución del coeficiente de rozamiento. Las pistas de desgaste y los residuos generados se caracterizaron mediante Microscopía Electrónica de Barrido, MEB. Los resultados muestran diferentes mecanismos de desgaste en cada par de material ensayado en función de la matriz y de la naturaleza de la bola empleada en el ensayo, encontrándose mayores tasas de desgaste con bola de nitruro de silicio. En una segunda fase, se obtienen recubrimientos, con dos polvos base cobalto cuyos tamaños de partícula son micrométrico y nanométrico, respectivamente, con el objetivo de estudiar la influencia del tamaño de partícula inicial sobre las propiedades a desgaste del recubrimiento. Los resultados obtenidos ponen de manifiesto una mayor resistencia al desgaste de los recubrimientos obtenidos con polvos nanoestructurados, bajo condiciones de carga elevadas, mientras que para cargas bajas ambos recubrimientos presentan un comportamiento similar a pesar de las diferencias microestructurales apreciadas.

  7. Factores asociados al desgaste profesional en los trabajadores del soporte vital básico del País Vasco: Un estudio cualitativo Factors associated with professional burnout among basic life support caregivers in the Basque Country: A qualitative research

    Directory of Open Access Journals (Sweden)

    Sendoa Ballesteros Peña

    2012-12-01

    Full Text Available Objetivos: Identificar factores de riesgo de desgaste profesional percibidos por los técnicos en emergencias sanitarias de las unidades de soporte vital básico del País Vasco. Metodología: Investigación cualitativa realizada mediante análisis de discurso en ocho entrevistas individuales a trabajadores del soporte vital básico con puntuaciones compatibles con afectación por desgaste profesional en el Inventario de Burnout de Maslach. Las variables estructurales tenidas en cuenta para la elección de los participantes fueron la antigüedad profesional (superior o inferior a 10 años y el centro de trabajo. Resultados: Los trabajadores presentan disconformidad con la actual estructura organizacional del sistema de emergencias y falta de proyección y reconocimiento de su rol profesional. Además manifiestan un progresivo distanciamiento afectivo para con los pacientes, con quienes ha aumentado el número de enfrentamientos debidos a dificultades de entendimiento causadas por situaciones de inadecuación del uso de los recursos asistenciales. Conclusiones: La estructura de organización del sistema de emergencias, el trato con el paciente y su familia y la situación profesional del técnico en emergencias son percibidos como elementos clave predisponentes de desgaste profesional.Objective: To identify possible factors associated with professional burnout among basic life support caregivers in the Basque Country. Method: A qualitative research was performed. We conducted an analysis of the discus of eight interpretive individual interviews with caregivers in basic life support units who presented scores compatible with burnout on the Maslach Burnout Inventory. The selection of participants was intentional. Results: The data analysis found that ambulance personnel have disagreed with emergency system organizational structure and recognition of their professional role. They show a progressive emotional detachment to patients. An inadequate use

  8. The use of radiotracer techniques to study lubrication and wear in large diesel engines; Emploi des indicateurs radioactifs pour l'etude de la lubrification et de l'usure dans les moteurs diesel de grande puissance; Ispol'zovanie metodov radioaktivnykh indikatorov dlya izucheniya smazki i iznosa bol'shikh dizel'nykh motorov; Aplicacion de los indicadores radiactivos al estudio de la lubricacion y desgaste de los motores diesel de gran potencia

    Energy Technology Data Exchange (ETDEWEB)

    Howes, Jr, J E; Braun, W J; Sunderman, D N [Battelle Memorial Institute, Columbus, OH (United States)

    1962-01-15

    de cylindres ont ete evaluees en fonction des conditions de fonctionnement de diesels ayant une puissance au frein de l'ordre de 1000 HP. On a mis au point des techniques permettant de marquer 200 gallons d'huile de graissage avec 60 mc de zinc-65 et de determiner la consommation d'huile par echantillonnage des gaz d'echappement dans des conditions variables de marche. L'evaluation de la consommation d'huile de graissage a pu etre effectuee en 10 minutes, alors qu'il fallait auparavant de -24 a 48 heures. On a mis au point des techniques d'irradiation pour l'activation neutronique de la partie inferieure d'une chemise de 48 pouces de longueur et de 8 pouces de diametre. Une protection appropriee contre les neutrons thermiques a permis de produire du manganese-54 d'une periode de 300 jours, ce qui a eu pour resultat de donner a la chemise, en vue des etudes sur l'usure, une longevite de 6 a 8 fois superieure a celle d'une chemise comparable exposee a des neutrons thermiques de maniere a produire du fer-59. Le fait qu'on puisse employer d'aussi grandes quantites de substances radioactives dans des installations standard de recherche sur les moteurs diesel ouvre un domaine entierement nouveau pour l'utilisation des indicateurs. L'activation selective et une protection judicieuse contre les neutrons thermiques multiplient les possibilites d'application de la technique des indicateurs parce qu'elles permettent de limiter les mesures aux points les plus interessants, de reduire la quantite totale de substances radioactives requises pour l'etude de l'usure des elements de grandes, dimensions, et de mesurer simultanement, sans grande difficulte, l'usure de diverses pieces dont la composition chimique est identique. (author) [Spanish] Los autores han aplicado indicadores radiactivos al estudio de la lubricacion y desgaste de los motores diesel de gran tamano en una escala que hasta ahora no se consideraba practica; operaron con absoluta seguridad y lograron excelentes

  9. Estudio del desgaste del flanco de carburos recubiertos y cermet durante el torneado de alta velocidad en seco del acero AISI 1045

    Directory of Open Access Journals (Sweden)

    Hernández-González, L. W.

    2011-06-01

    Full Text Available This work deals with the experimental study of the flank wear evolution of two coating carbide inserts and a cermet insert during the dry finishing turning of AISI 1045 steel with 400, 500 and 600 m/min cutting speeds. The results were analyzed using the variance analysis and lineal regression analysis in order to describe the relationship between the flank wear and machining time, obtaining the adjusted model equation. The investigation demonstrated a significant effect of cutting speed and machining time on the flank wear at high speed machining. The three coating layers insert showed the best performance while the two layers insert had the worst behaviour of the cutting tool wear at high cutting speeds.

    El objetivo de este trabajo es el estudio experimental de la evolución del desgaste del flanco respecto al tiempo de dos insertos de carburo recubiertos y un cermet durante el torneado de acabado en seco del acero AISI 1045 con velocidades de corte de 400, 500 y 600 m/min. Los resultados fueron comparados utilizando el análisis de varianza y el análisis de regresión lineal para describir la relación entre el desgaste del flanco y el tiempo de maquinado, obteniéndose la ecuación del modelo ajustado. La investigación demostró un efecto significativo de la velocidad de corte y del tiempo de maquinado en el desgaste del flanco en el maquinado de alta velocidad. El mejor desempeño se obtuvo para el carburo recubierto con tres capas, mientras que el carburo con dos capas sufrió el mayor desgaste a elevadas velocidades de corte.

  10. Estimativa do coeficiente de reaeração da água em canal raso de fundo deslizante

    Directory of Open Access Journals (Sweden)

    Flávia Martins de Queiroz

    2015-03-01

    Full Text Available O coeficiente de reaeração, K2, é a variável de maior influência na autodepuração de corpos hídricos; portanto, estimativas confiáveis são de suma importância. As previsões de K2, por meio de equações, em condições de escoamento raso são, geralmente, superestimadas. Por isso, neste trabalho, os objetivos foram estudar a reoxigenação da água limpa em canal hidráulico de fundo deslizante, com pequenas profundidades de água e diferentes velocidades de escoamento, inferir sobre as principais variáveis hidrodinâmicas intervenientes no processo e, com base nelas, propor equação de estimativa de K2. Com a concentração de oxigênio na água ao longo do tempo, estimou-se K2. Inferiu-se, dos resultados, que as variáveis velocidade média (V e velocidade de corte (u*, profundidade (H, números de Froude (Fr e de Reynolds (R, declividade (S e fator de forma (ff afetaram K2, e a melhor equação foi a que incluiu as três últimas variáveis.

  11. Construcción de silos con encofrados deslizantes - Santa Cruz de Tenerife – España

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    Barrios Martínez, M.

    1976-10-01

    Full Text Available These cereal and oil-cake silos are made up of 10 exterior cylindrical cells, with an inner diameter of 6 m and a height of 31.88 m. The cells are joined together by means of walls whereby four additional octagonal cells are created. Out of these, three are subdivided into four cells and the fourth forms the central silo. Below this unit there is a corridor for the emptying of the silos. The work has been carried out with a travelling form with the following characteristics: mixed with regard to shape and materials; stiff, since the top platforms are connected; and it has a constant cross-section as the dimensions of the silos remain the same throughout the whole height. The form was lifted by means of elevation devices, controlled by a centralized hydraulic mechanism. In view of the characteristics of the travelling form, the concrete used ¡n the work had to fulfill several very special conditions, notably different from these applying to the concrete that is normally used for fixed forms. For this reason, it was submitted to a great number of studies and tests until the requirements had been met. The construction was finished in record time: in the first place, because a detailed programme had been worked out in advance, consisting of a diagram of bars and preference network and secondly, because continuous concreting was applied with day and night shifts, whebery the foreseen two and a half months for finishing the silos were reduced to 12 days.Estos silos, destinados a almacenamiento de cereales y borujo, están formados por 10 celdas exteriores cilíndricas, de 6 m de diámetro interior y 31,88 m de altura, que se unen entre sí por medio de muros, dando lugar a cuatro celdas adicionales de forma octogonal. De éstas, tres están subdivididas en cuatro interceldas, quedando la cuarta como silo central. Debajo del conjunto se ha dispuesto una galería para el vaciado de los silos. La obra se ha realizado con un encofrado deslizante

  12. Resistencia a la corrosión y desgaste de recubrinnientos deTiN obtenidos por PVD

    Directory of Open Access Journals (Sweden)

    Conde, A.

    2005-12-01

    Full Text Available Surface hardening techniques for metallic alloys are widely used to achieve layers of very high hardness and corrosion and wear resistance. In the present paper TiN coatings are obtained by PVD on a tool steel. The films are characterized by SEM, X-ray diffraction and XPS. Corrosion behaviour in NaCl solution showed the importance of the presence of defects on the PVD coating due to the different electrochemical behaviour of the steel base. Pin-on-disk measurements at approximately 40% RH against a corundum (Al2O3 ball showed a significant decrease in the wear rate compared with the results for the standard tool steel.

    Los tratamientos de endurecimiento superficial de aleaciones metálicas se utilizan para lograr capas de muy elevada dureza, resistencia a la corrosión y desgaste. En este trabajo, se estudia el comportamiento de recubrimientos de TiN obtenidos mediante PVD sobre aceros de herramientas. Las capas obtenidas se caracterizan mediante microscopía electrónica de barrido, difracción de rayos X y XPS. Se analiza el comportamiento frente a la corrosión de las capas protectoras, así como la influencia del substrato en su comportamiento en soluciones de NaCl. Finalmente, se realizan ensayos de desgaste por deslizamiento en seco mediante la técnica de pin-on-disk, comprobándose la mayor resistencia de estas capas.

  13. DESGASTE POR ABRASIÓN DEL ACERO API 5L X65 REVESTIDO CON NIOBIO POR ASPERSIÓN TÉRMICA A PLASMA Y CON INCONEL 625 POR SOLDADURA

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    JOSE MATOS

    2012-01-01

    Full Text Available El objetivo de este trabajo fue evaluar y caracterizar el comportamiento mecánico en desgaste del acero API 5L X65, revestido con niobio en comparación al desempeño del revestimiento de la aleación de inconel 625 empleados en la industria de petróleo y gas. El revestimiento de niobio fue obtenido por el proceso de aspersión térmica a plasma de arco no transferido y el revestimiento inconel 625 por soldadura con electrodo revestido. La resistencia al desgaste por abrasión fue evaluada según la norma Petrobras N-2568, en un tribómetro CTER, la rugosidad y el volumen de material desgastado se determinó a través de perfilometría y la dureza de los revestimientos por microscopia Vickers. Los revestimientos obtenidos fueron caracterizados respecto a su morfología por microscopia electrónica de barrido (MEB y microscopía óptica (MO. La mayor dureza del revestimiento con niobio obtenido puede haber contribuido a reducir la tasa de desgaste en comparación con el revestimiento de inconel 625.

  14. Comportamiento de la Resistencia al desgaste erosivo de recubrimientos de alúmina

    Directory of Open Access Journals (Sweden)

    Alfonso Santos Jaimes

    2018-01-01

    Full Text Available This article presents the results of the research related to the experimental behavior of alumina coatings obtained from micrometric size particles and deposited through a thermal spraying by flame process on an AISI 304 stainless steel substrate when it is subjected to erosive wear caused by cavitation through a vibratory apparatus. The methodology used to reach the proposed objective consisted of five phases in the first a morphological and chemical characterization of the materials used, was carried out; the second was the adaptation of UIP1000hd ultrasound equipment to the requirements demanded by the ASTM G32-16 standard (standard test method for erosion by cavitation using vibrating apparatus; afterwards, test pieces of AISI 304 stainless steel were tested to verify the performance of the equipment used, the validation of the wear phenomenon present in the specimens was carried out through scanning electron microscopy tests in order to observe the evolution of the footprint left over the specimen; as a fourth phase, the deposition of the alumina coatings was carried out through a conventional oxyacetylene combustion equipment and an Eutalloy 85 BX gun; finally micro-hardness and erosive wear resistance tests were carried out on AISI 304 stainless steel specimens without and with alumina coatings. The results obtained allowed to validate the operation of the adapted equipment for the performance of the tests since the percentage of average error between the experimental and theoretical data was of 4,5% for AISI 304 stainless steel; regarding the behavior of alumina coatings a 26,23% reduction of material loss was obtained with respect to the AISI 304 stainless steel which represents a significant improvement and encourages its use when mechanical elements are subjected to erosive wear caused by cavitation.

  15. COMPARAÇÃO DO CRESCIMENTO E DO DESGASTE DO CASCO EM BOVINOS TAURINOS E ZEBUÍNOS RATES OF HOOF GROWTH AND WEAR IN ZEBUINE AND TAURINE CATTLE

    Directory of Open Access Journals (Sweden)

    Rüdiger Daniel Ollhoff

    2001-02-01

    Full Text Available No presente trabalho, mediram-se o crescimento e o desgaste do casco dos quatro dígitos laterais, em duas posições (dorsal e lateral, em quatro garrotes da raça Jersey e quatro da raça Gir, mantidos em "tie-stall", sobre piso de cimento recoberto por alta camada de maravalha. O trabalho transcorreu no período de novembro de 1997 a abril de 1998. As medidas de crescimento e desgaste do casco foram obtidas empregando-se a técnica clássica descrita por Hahn et al. (1986. Não ocorreram diferenças significativas no crescimento e no desgaste dos cascos entre as raças estudadas, assim como entre as unhas dos cascos dos membros anteriores e posteriores. Em ambas as raças, foram constatados maiores desgaste e crescimento da região lateral (lado abaxial do casco, em relação à região dorsal, indicando que grande parte do contato e sustentação do corpo ocorre na área lateral do casco. A apara funcional acelera o crescimento do casco, porém não altera a taxa de desgaste.Rates of hoof growth and wear, on both dorsal and lateral surfaces of front and rear outside claws, were measured in four Jersey and four Gir yearling steers kept on a tie-stall system on a concrete ground covered by deep layer of sawdust. Measurements were taken from November 1997 to April 1998 according to the classical technique described by HAHN et al. (1986. No significant differences in the growth and wear of the claws were found between the two breeds. There was no significant difference of growth and wear rates between front and rear claws. Horn of the lateral walls grew and wore faster in taurine and zebuine cattle, indicating that most of the weight-bearing and contact to the soil is given through this region. Functional trimming increases claw horn growth but does not interfere with wear rates.

  16. ESTUDO DO DESGASTE DE REVESTIMENTO INTERNO DE UM MOINHO DE BOLAS OPERANDO COM ROCHA FOSFÁTICA

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    André Carlos Silva

    2014-07-01

    Full Text Available O revestimento interno dos moinhos vem tomando maior proeminência devido à sua influência direta na eficiência de moagem e pelo alto custo agregado relacionado ao seu tempo de operação. Uma vez que o desgaste do revestimento não é uniforme, foi realizado o acompanhamento do desgaste do revestimento interno do moinho de bolas (SAG 4,87 x 6,09 m da empresa Vale Fertilizantes S.A. Unidade Catalão-GO. Tal moinho trabalha com rocha fosfática e o monitoramento se deu através de um dispositivo prático visando à determinação do comportamento do desgaste do revestimento ao longo de toda a extensão do moinho, desde a alimentação até a descarga, bem como a variação em um único perfil de uma placa do revestimento. Observou-se que o desgaste não é uniforme tanto ao longo do moinho quanto em um mesmo perfil, indicando que o maior desgaste ocorre nos primeiros e últimos 1,5 metros, com valores muito próximos. Na alimentação do moinho o desgaste específico foi de 0,60 g/t, na descarga de 0,63 g/t e no do centro do moinho de aproximadamente 0,55g/t.

  17. Inteligencia emocional percibida y desgaste laboral en médicos internos de pregrado

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    R. Ortiz-Acosta

    Full Text Available Objetivo: Analizar la relación entre los niveles de inteligencia emocional percibida y desgaste laboral en médicos internos de pregrado. Sujetos y métodos: Para ello se utilizó la Trait Meta-Mood Scale, que evalúa la inteligencia emocional percibida, y el inventario de burnout de Maslach, en 44 médicos internos de pregrado de tres hospitales de los Servicios de Salud de Sonora. Resultados: El factor de atención emocional se relaciona negativamente con agotamiento. Claridad correlaciona de manera positiva con reparación emocional y realización personal, y de forma negativa con agotamiento y despersonalización. Reparación de las emociones correlaciona de forma negativa con agotamiento y despersonalización, y de manera positiva con realización personal. Los análisis de regresión revelaron que el desgaste laboral del médico de pregrado se explicaba por una baja atención emocional y falta de claridad en sus emociones. Conclusión: Estos hallazgos evidencian que ciertos factores emocionales deben tenerse en cuenta para explicar el desgaste laboral en el médico interno de pregrado.

  18. Scratch resistance of SiO{sub 2} and SiO{sub 2} - ZrO{sub 2} sol-gel coatings on glass-ceramic obtained by sintering; Resistencia al desgaste de recubrimientos sol-gel de SiO{sub 2} y SiO{sub 2} - ZrO{sub 2} sobre materiales vitroceramicos obtenidos por sinterizacion

    Energy Technology Data Exchange (ETDEWEB)

    Soares, V. O.; Soares, P.; Peitl, O.; Zanotto, E. D.; Duran, A.; Castro, Y.

    2013-10-01

    The sol-gel process is widely used to obtain coatings on glass-ceramic substrates in order to improve the scratch and abrasion resistance, also providing a bright and homogeneous appearance of a glaze avoiding expensive final polishing treatments. This paper describes the preparation of silica and silica / zirconia coatings by sol-gel method on Li{sub 2}O-Al{sub 2}O3-SiO{sub 2} (LAS) glassceramic substrates produced by sintering. The coatings were deposited by dip-coating on LAS substrates and characterized by optical microscopy and spectral ellipsometry. On the other hand, hardness and elastic modulus, coefficient of friction and abrasion and scratch resistance of the coatings were determined and compared with the substrate properties. Coatings deposited on LAS glass-ceramic confere the substrate a bright and homogeneous aspect, similar to a glaze, improving the appearance and avoiding the final polishing. However these coatings do not increase the scratch resistance of the substrate only equaling the properties of the glass-ceramic. (Author)

  19. Estudio del desgaste de aceros rápidos pulvimetalúrgicos M3/2 reforzados con carburo de niobio mediante el ensayo pin-on-disk

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    Candela, N.

    2005-10-01

    Full Text Available In this work, composite materials M3/2 high-speed steel reinforced with 5,10 and 15 %, in volume, of niobium carbide have been obtained to improve the wear behaviour. The materials were prepared by powder metallurgy using steel and carbide powders that were mechanically ball milled in a planetary mill, and then hot isostatically pressed. The wear behaviour was determined by pin-on-disk tests. The materials present a microstructure consisting of grains with a few microns in size and fine MC and M6C particles homogeneously dispersed in its interior. In the case of reinforced materials, reinforcing carbides particles are placed mainly at the surface of the prior steel powder particle boundaries. The wear behaviour was evaluated from friction and wear coefficients, and also from weight loss. The addition of niobium carbide improves the wear properties of the tool steel in both martensitic and tempered conditions. A decrease of the weight loss and the wear coefficient is observed with increasing volume fraction of NbC

    En este trabajo se han preparado materiales compuestos de acero rápido M3/2 reforzado con un 5, un 10 y un 15 % en volumen de carburos de niobio con el objeto de mejorar sus propiedades mecánicas y resistencia al desgaste. La fabricación de los distintos materiales compuestos se realizó mediante molienda mecánica de polvo de acero rápido y carburo en un molino de alta energía, y compactación isostática en caliente. El comportamiento al desgaste se determinó a través de ensayos pin-on-disk. El material de partida presenta una microestructura con un tamaño de grano de pocas mieras y pequeños carburos MC y M6C homogéneamente dispersos en su interior. En el caso de los materiales reforzados, las partículas reforzantes de carburo se sitúan mayoritariamente sobre la superficie de las partículas originales de polvo de acero. El comportamiento al desgaste se evaluó a partir del coeficiente

  20. Comportamiento a desgaste de recubrimientos de material compuesto de matriz de aluminio fabricados por proyección térmica

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    Campo, M.

    2007-10-01

    Full Text Available In this work, the wear behaviour of coatings made of aluminium matrix composites reinforced with 20% of SiC particles and manufactured by thermal spray method with oxyacetylene flame has been investigated. The wear behaviour between coatings with uncoated particles and sol-gel silica coated ones heat treated at 500 °C and 725 °C have been compared. The sprayed coatings with silica coated particles are more homogenous and less porous due to increase of wettability by molten aluminium that takes place on coated particles. The microstructure of the sprayed coatings, the wear surfaces and the wear debris have been anlysed using optical microscopy, scanning electron microscopy and microanalysis techniques (EDX. The results show a smaller wear rate, a lower friction coefficient and more reduced loss of mass for the coatings sprayed with particles with sol-gel silica coatings than those made with uncoated particles.

    En este trabajo se ha evaluado el comportamiento a desgaste de recubrimientos de material compuesto reforzado con un 20 % de partículas de SiC fabricados por proyección térmica con llama oxiacetilénica. Se ha comparado el desgaste de los recubrimientos proyectados con partículas sin recubrir y recubiertas con la sílice sol-gel tratada térmicamente a 500 °C y 725 °C. Los recubrimientos proyectados con partículas recubiertas de sílice son más homogéneos y menos porosos debido fundamentalmente al aumento de su mojabilidad por aluminio fundido. La microestructura de los recubrimientos proyectados, de las superficies desgastadas y del material eliminado en los ensayos pin-on-disc se ha analizado por técnicas de microscopía óptica y electrónica de barrido junto a microanálisis EDX. Los resultados obtenidos muestran una menor tasa de desgaste, menor coeficiente de rozamiento y menor pérdida de masa para los recubrimientos proyectados con las partículas con el recubrimiento de sílice sol-gel que para los de las

  1. Análisis experimental del desgaste entre UHMWPE y acero inoxidable 316l empleados en la manufactura de prótesis coxofemorales

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    Ricardo Gustavo Rodríguez Cañizo

    2010-07-01

    Full Text Available Título en inglés: Experimental wear analysis of UHMWPE and stainless 316l used in the manufacturing of coxofemoral prosthesis. Resumen La causa más común de falla en prótesis coxofemorales es el aflojamiento entre los componentes que conforman el sistema, de manera específica la copa acetabular y la cabeza femoral. En esta investigación se presenta un análisis tribológico del desgaste en los componentes mencionados, ya que cuando las superficies en contacto se desgastan, la funcionalidad mecánica del sistema se compromete, debido al cambio de geometría de los mismos, dando como resultado un juego mecánico entre la copa y la cabeza. Los materiales considerados en este estudio son el polietileno de ultra elevado peso molecular (UHMWPE, por sus siglas en inglés para la copa acetabular, y acero inoxidable 316L para la cabeza femoral. Esta combinación de materiales representa hoy en día la recomendación más usual por parte de los cirujanos para pacientes de la tercera edad. La tasa anual de desgaste se determinó de manera experimental y se cuantificó la cantidad de material desprendido durante el contacto. Se establecieron las condiciones de carga de forma analítica, considerando las que actúan sobre la cabeza femoral a lo largo del área de desgaste durante la marcha humana. Posteriormente, se realizó el análisis experimental de desgaste utilizando una máquina tribológica de configuración perno-sobre-disco (pin-on-disk, diseñada de manera específica para este estudio. Las pruebas para determinar la pérdida volumétrica de los componentes se realizaron bajo tres condiciones de operación: en seco, lubricada con agua destilada y lubricada con suero bovino. El marco experimental considerado consistió en pernos de UHMWPE sobre discos de acero inoxidable 316L simulando el desgaste equivalente a diez años de uso de la prótesis. Finalmente, de los resultados obtenidos se puede establecer que el desgaste y la cantidad de part

  2. Medición del desgaste laboral en el ramo comercial

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    Marianna Barrios León

    2013-07-01

    Full Text Available El desempeño del capital humano se ve influido por múltiples factores; uno de ellos es el desgaste laboral. Esta investigación tiene por objeto identificar las dimensiones fundamentales que participarían en la medición del desgaste percibido por los trabajadores que laboran en el ramo comercial. La profundidad de este estudio lo clasifica como explicativo con diseño de campo, usándose una muestra de 64 personas de una empresa comercializadora, donde se realizaron entrevistas estructuradas y se aplicó una adaptación del Maslach Burnout Inventory (MBI. El instrumento fue validado por contenido, criterio y constructo, y el cálculo del alfa de cronbach indicó una fiabilidad adecuada. Por otra parte, el Análisis de Factores, la Extracción de Componentes Principales y el contraste de los resultados con otras aplicaciones en el área, permitieron determinar la existencia de cinco dimensiones: 1 Sensación de Desgaste, 2 Manejo Emocional, 3 Manejo de las Relaciones Laborales, 4 Afinidad en las Relaciones Laborales, y 5 Despersonalización, donde resalta que las relaciones laborales son un factor clave para percibir el desgaste y se mantiene la subescala de despersonalización como en el instrumento inicial. A partir de estas dimensiones se pueden definir estrategias organizacionales para la mejora de la productividad. The human capital performance is influenced by many factors, one of them is burnout. This research aims to identify the key dimensions that participate in the exhasut measurement perceived by employees working in the trade sector. The depth of this study was classified as explanatory design field, using one sample of 64 people in a trading company where structured interviews were conducted and applied an adaptation of the Maslach Burnout Inventory (MBI. The instrument was validated by content, and criterion construct and calculation of Cronbach’s alpha indicated adequate reliability. Moreover, Factor Analysis, Principal

  3. Psychological exhaustion and disorders of health in psychology students Desgaste psíquico y problemas de salud en estudiantes de psicologia Desgaste psíquico e problemas de saúde em estudantes de psicologia

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    Hugo Figueiredo-Ferraz

    2009-06-01

    Full Text Available El objetivo del estudio fue analizar los niveles de Desgaste psíquico y Desencanto en estudiantes de Psicología, la Sobrecarga y su relación con los Problemas de salud. Participaron 154 estudiantes universitarios de Psicología de 3º (48% y 4º (52% grado. Desgaste psíquico y Desencanto se evaluaron mediante el Cuestionario para la Evaluación del Síndrome de Quemarse por el Trabajo, Problemas de salud mediante una escala de once ítems y Sobrecarga mediante un ítem. Los estudiantes de cuarto percibían significativamente mayores niveles de Sobrecarga, Desgaste psíquico y Desencanto que los de tercero.O objectivo deste estudo foi analisar os níveis de desgaste psíquico e desencanto em estudantes de Psicología, a sobrecarga e a sua relação com os problemas de saúde. Participaram 154 estudantes universitários de Psicologia do 3º (48% e 4º (52% anos. Desgaste psíquico e desencanto foram avaliados mediante o Questionario para la Evaluación del Síndrome de Quemarse por el Trabajo, problemas de saúde mediante uma escala de onze itens e sobrecarga mediante um item. Os estudantes do quarto ano sentiam de maneira significativa maiores níveis de sobrecarga, desgaste psíquico e desencanto que os de terceiro ano.The aim of the study was to examine the levels of Psychological Exhaustion and Disillusionment in students of Psychology, the work overload and its relationship with Disorders of Health. The research participants were 154 university students of Psychology from junior (48% and senior. (52%. Psychological Exhaustion and Disillusionment were analysed with the Spanish Burnout Inventory (SBI, Disorders of Health with an eleven-item scale and Work overload with one item. The students from senior perceived higher Work overload, Psychological Exhaustion and Disillusionment than the students from junior.

  4. Mecanismos de desgaste en materiales compuestos de matriz acero rápido fabricados por técnicas pulvimetalúrgicas

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    Gordo, E.

    2001-04-01

    un molino de alta energía, en seco, a 200 r.p.m., durante 40 h. Después de un recocido de eliminación de tensiones, se siguieron dos vías para la consolidación de los polvos: (1 compactación en matriz y sinterización en vacío y (2 compactación isostática en caliente (HIP. El estudio del comportamiento a desgaste de los materiales se evaluó mediante el método ''pin-ondisc”. Los ensayos se realizaron utilizando como disco el material a ensayar, y como “piri” una bola de alúmina. Los resultados indican que, la consolidación del material por HIP mejora considerablemente su resistencia al desgaste, respecto a la consolidación por sinterizado.

  5. El desgaste dental. ¿Un método fiable para la estimación de la edad?

    OpenAIRE

    Trujillo Mederos, Aioze; Calderón Ordóñez, Alejandra

    2011-01-01

    En aquest pòster es qüestiona si la utilització del desgast dental, per sí mateix, com a mètode per estimar l’edat de la mort és realment vàlid en totes les societats o si abans de proposar-se a utilitzar aquest mètode, s’ha de tenir en compte el context cultural de la població a estudiar. Per això, s’han seleccionat part de les restes bioantropològiques procedents del jaciment inca de Chinchero (Cuzco, Perú), l’edat osteològica dels quals no correspon amb l’edat estimada a partir del desgast...

  6. Produtivismo e precariedade subjetiva na universidade pública: o desgaste mental dos docentes

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    Marcia Hespanhol Bernardo

    2014-01-01

    Full Text Available Nos últimos anos, tem-se observado cada vez mais características típicas de mercado presentes na universidade pública. No Brasil, o aspecto com maior destaque nas publicações é o "produtivismo acadêmico", que tem como mote a ênfase na quantidade de produções bibliográficas. Neste artigo, busca-se discutir as características desse modelo, partindo-se do pressuposto que ele conduza a uma situação de precariedade subjetiva para os docentes. Para tal, apresenta-se o resultado de uma pesquisa qualitativa com professores de uma universidade pública, realizada por meio de entrevistas reflexivas. Os resultados indicam que a precariedade subjetiva vivenciada leva a um desgaste mental, o qual, por sua vez, pode ter como consequência o sofrimento psíquico e o adoecimento. Apesar de se mostrarem conscientes do processo que vivenciam, alguns docentes buscam adotar táticas individuais cotidianas de "sobrevivência", enquanto as estratégias coletivas com vistas à transformação são pouco enfatizadas.

  7. Construcción y puesta en funcionamiento de una máquina de cilindros cruzados para la evaluación del desgaste adhesivo

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    Sandro Báez P.

    2004-01-01

    Full Text Available En esta investigación se evaluó el desgaste adhesivo de cuatro metales (fundición gris, latón 60- 40, bronce fosforado y un acero AISI 1020, en un tribómetro de cilindros cruzados, bajo la norma ASTM G- 83-96. Para lograr dicho objetivo, se diseñó, construyó y puso en marcha una máquina de cilindros cruzados, la cual contiene dos probetas cilíndricas (una estática y una giratoria, que fueron maquinadas y pulidas con lijas hasta obtener una superficie con una rugosidad máxima de 0.34 mm. Con el volumen de metal perdido por cada material, se calculó su velocidad promedio de corrosión y se determinó el coeficiente de desgaste. Además, se realizaron ensayos a cada material, para determinar los perfiles de desgaste respectivos (Gramos de metal perdido vs Tiempo. En este trabajo se obtuvo un coeficiente de variación máximo, entre los cuatro metales, de 4.3%, indicando una buena correlación de los resultados obtenidos. Los coeficientes de desgaste se consideraron aceptables, puesto que sus valores corresponden y son del mismo orden a los establecidos en la literatura. Igualmente, los perfiles del desgaste mostraron las tres etapas del proceso, similares a los encontrados en otros trabajos realizados.

  8. Trabalho de jovens estudantes de uma escola pública: fortalecimento ou desgaste? Trabajo de jóvenes estudiantes de una escuela pública: fortalecimiento o desgaste? Work of young students of a public school: strengthening or weakening?

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    Sheila Aparecida Ferreira Lachtim

    2009-04-01

    Full Text Available O objetivo desta pesquisa foi reconhecer os potenciais de desgaste e de fortalecimento de jovens trabalhadores que estudam em uma escola pública de um município da RMSP. Trata-se de um estudo qualitativo, que entrevistou 19 estudantes, de 16 a 20 anos do período noturno. Os principais potenciais de desgaste foram: longa jornada de trabalho, excesso de responsabilidade, falta de estabilidade e trabalho essencialmente manual, fragmentado e repetitivo. Os poucos potenciais de fortalecimento foram: socialização e satisfação de necessidades de reprodução social. Verificou-se o fenômeno da regressão intergeracional. O estudo do binômio desgaste-fortalecimento dos jovens denuncia mais sentidos negativos do que positivos na concomitância trabalho-estudo, intrinsecamente relacionada à necessidade de sobrevivência das famílias. Esse processo é potencialmente desgastante, podendo ocasionar problemas de saúde aos jovens.El objetivo de esta investigación fue reconocer los potenciales de desgaste y de fortalecimiento de jóvenes trabajadores que estudian en un colegio público de una ciudad de RMSP. En este estudio cualitativo, se entrevistó a 19 estudiantes del periodo nocturno, de 16 a 20 años. Los principales potenciales de desgaste fueron: larga jornada de trabajo, exceso de responsabilidad, falta de estabilidad y trabajo principalmente manual, fragmentado y repetitivo. Los pocos potenciales de fortalecimiento fueron: socialización y satisfacción de las necesidades de reproducción social. Se verificó el fenómeno de regresión entre generaciones. El estudio del binomio desgaste-fortalecimiento de los jóvenes denuncia más sentidos negativos en la concomitancia trabajo-estudio, intrínsicamente relacionada a la necesidad de sobrevivencia de las familias. Ese proceso es potencialmente desgastante, pudiendo ocasionar problemas de salud a los jóvenes.The objective of this research was to recognize the strengthening and weakening

  9. Cargas e desgastes de trabalho vivenciados entre trabalhadores de saúde em um hospital de ensino Descripción de cargas de trabajo y el desgaste experimentado entre trabajadores de salud en un hospital universitario Description of workloads and fatigue experienced among health workers in a teaching hospital

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    Leni de Lima Santana

    2013-03-01

    Full Text Available Estudo exploratório, de caráter descritivo e de abordagem quantitativa, alicerçado nas categorias "processo de trabalho", "cargas de trabalho" e "desgaste" em um hospital de ensino em Curitiba, região sul do Brasil. Neste artigo, são caracterizadas as cargas e os desgastes vivenciados em um hospital universitário, captados pelo estudo prévio intitulado "Sistema de monitoramento da saúde do trabalhador de enfermagem" (SIMOSTE. Os resultados demonstram que o gênero feminino foi o mais acometido (85,9%; os profissionais mais afetados foram os auxiliares de enfermagem (53,1%. O maior número de afastamentos ocorreu por doenças do sistema osteoarticular (25,2% e, dentre as cargas apresentadas, as mais expressivas foram as mecânicas e fisiológicas, com 33,06%, cada. Estes resultados poderão subsidiar estratégias de intervenção nas políticas direcionadas à saúde do trabalhador, para assegurar uma melhor qualidade de vida a este profissional e, por consequência, promover melhorias na qualidade da assistência prestada ao usuário.Estudio exploratorio, descriptivo y cuantitativo, basado en el proceso de trabajo, las cargas de trabajo y el desgaste en un hospital universitario en Curitiba, sur de Brasil. En este artículo se caracteriza la carga y el estrés experimentado en un hospital universitario, planteada por un estudio previo titulado "Sistema de vigilancia de la salud de los trabajadores de enfermería". Los resultados muestran que las mujeres (85,9% y los auxiliares de enfermería eran los profesionales más afectados (53,1%. El mayor número de ausencia del trabajo se debieron a enfermedades del sistema musculoesquelético (25,2% y entre los cargos presentados, los más significativos fueron el mecánico y el fisiológico con el 33,06% cada uno. Estos resultados pueden apoyar las estrategias de intervención en las políticas dirigidas a la salud de los trabajadores, para garantizar una mejor calidad de vida a este trabajo y

  10. Síndrome de desgaste profesional en enfermeras/os del área metropolitana de Barranquilla

    OpenAIRE

    Rafael Tuesca-Molina; María Iguarán Urdaneta; Melissa Suárez Lafaurie; Glenda Vargas Torres; Deisy Vergara Serpa

    2006-01-01

    Objetivo: Analizar el grado de desgaste profesional de las/os enfermeras/os que laboran en los área metropolitana de Barranquilla (Colombia). Material y Métodos: Se diseñó un estudio descriptivo exploratorio con participación voluntaria de 103 enfermeras/os, a quienes se los administró el Maslach Burnout Inventory (MBI), en el que se valoran el cansancio emocional, la despersonalización, los logros personales, variables sociodemográficas y laborales. Resultados: La edad medi...

  11. Estudio del comportamiento de los recargues multicapas de depósitos soldados de fundición blanca al cromo // Study of the hard facing weld behavior in deposits of white chromium steels.

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    R. Collazo-Carceller

    2009-05-01

    Full Text Available Se determina la influencia de los parámetros Energía introducida (Hi, Número de capas (Nc yAncho del depósito (Ad, en la morfología y el incremento de la resistencia al desgaste abrasivo decapas depositadas sobre acero 1020 utilizando el electrodo de fundición blanca al cromo UTPLedurit – 61. Empleando la microscopia óptica se identificaron y cuantificaron las fases presentes,analizando su efecto en el desgaste. Siendo determinante la influencia de la inclinación de lasdendritas y su posición con respecto a 90° en el incremento de la resistencia al desgaste abrasivo.Se caracterizaron los posibles mecanismos de daño superficial provocado por desgaste abrasivoempleando la microscopia electrónica de barrido. Se propusieron modelos lineales paracorrelacionar la influencia de la cantidad, tamaño, dispersión de los carburos y el ángulo deinclinación de las dendritas, en el incremento de la resistencia al desgaste.Palabras claves: morfología, desgaste abrasivo, parámetros de soldadura, dendritas, modelos.__________________________________________________________________________AbstractThe influence of different parameters in layer morphology and abrasion resistance of Fe-Cr-Celectrodes UTP Ledurit – 61 on steel 1020 was studied. Introduced Energy (Hi, Number of Layers(Nc, and Deposit Width (Ad were the main parameters considered. The metallographicidentification and quantification of metal phases and the determination of their effect in abrasionresistance were made with optical microscopy. The abrasive wear test characterized by scanningelectron microscopy, defines a possible mechanism of surface damage. It was found that the angleformed between a normal line to the surface and the dendrite inclination is directly related withthe increment of wear resistance. Lineal models that correlate wear resistance with quantity, size,and carbide dispersion and dendrite angle inclination were also developed.Key words: morphology, abrasive

  12. Caracterizacíón del desgaste de electrodos de grafito en electroerosión por penetración

    OpenAIRE

    Margüello Juaristi, Ignacio

    2015-01-01

    Estudio sobre la caracterización del desgaste de electrodos en electroerosión por penetración, así como el estudio del gap y de las dimensiones finales de las cavidades erosionadas en función de la tecnología de erosión empleada.

  13. Control activo de vibraciones en estructuras tipo edificio sometidas a sismos utilizando múltiple retroalimentación positiva de la posición y modos deslizantes

    Directory of Open Access Journals (Sweden)

    Josué Enríquez-Zárate

    2014-01-01

    Full Text Available Este trabajo considera el análisis estructural y dinámico de un a estructura tipo edificio de tres pisos con un absorbedor de v ibraciones pasivo/activo. La base de la estructura se perturba con un gene rador de vibraciones, proporcionando fuerzas de excitación y ru ido emulando transporte terrestre, trenes subterráneos y sismos, c omunes en la Ciudad de México. Se considera un registro sísmico real de magnitud 8.1Mw, conteniendo algunas frecuencias resonantes de l a estructura. La estructura mecánica se modela con la metodolog ía de Euler-Lagrange y se valida con técnicas de análisis modal exper imental. El esquema de control activo se diseña para atenuar la respuesta vibratoria del sistema, ocasionada por las fuerzas armónicas qu e actúan en la base, empleando múltiple retroalimentación posit iva de la posición y control por modos deslizantes para mejorar la robust ez del sistema en lazo cerrado y atenuar tres modos de vibració n. Resultados en simulación y experimentales describen el desempeñ o del sistema completo.

  14. Análisis mecánico y tribológico de los recubrimientos fe-cr-ni-c y ni-al-mo

    Directory of Open Access Journals (Sweden)

    JORGE E. MUÑOZ

    2007-01-01

    Full Text Available En este trabajo de investigación se evaluaron dos recubrimientos aplicados por medio de la técnica de rociado térmico por combustión, la aleación: Ni=89%, Al = 5,5%, Mo=5,5% y la aleación Fe=81,8%, Cr=16%, Ni=2%, C=0,2. La preparación superficial de las probetas se realizó usando chorro de arena. Se realizaron pruebas de resistencia al cortante, adherencia, desgaste abrasivo, desgaste por deslizamiento y flexión en cuatro puntos. El recubrimiento Fe-Cr-Ni-C presentó menor pérdida de masa, tanto para desgaste abrasivo como para el desgaste por deslizamiento. La multicapa presentó una mayor porosidad en el recubrimiento Ni-Al- Mo usado como capa base y la capa exterior de Fe-Cr-Ni-C presentó mayor cantidad de partículas no fundidas y óxidos. La falla ocurrida en el ensayo de adherencia para las probetas con recubrimiento multicapa fue de característica adhesiva y cohesiva. El esfuerzo en el que se presenta la fisura por flexión en el recubrimiento multicapa disminuyó con el aumento del espesor

  15. O desgaste do trabalhador de enfermagem: relação trabalho de enfermagem e saúde do trabalhador

    Directory of Open Access Journals (Sweden)

    Vanda Elisa Felli da Silva

    Full Text Available O estudo busca a compreensão do processo saúde-doença, vivenciado pelos trabalhadores de enfermagem no desempenho de seu trabalho, fundamentado na determinação social desse processo. Evidencia as particularidades da relação trabalho-saúde de uma realidade concreta, decompondo e recompondo as intermediações processo de valorização, processo de trabalho, cargas de trabalho e desgaste, o que permitiu explicitar o perfil de morbidade desses trabalhadores. Nesse perfil, os ferimentos pérfuro-cortantes e as doenças ósteo-músculo-articulares aparecem como danos característicos desse grupo de trabalhadores de enfermagem.

  16. O desgaste do trabalhador de enfermagem: relação trabalho de enfermagem e saúde do trabalhador

    Directory of Open Access Journals (Sweden)

    Vanda Elisa Felli da Silva

    1998-12-01

    Full Text Available O estudo busca a compreensão do processo saúde-doença, vivenciado pelos trabalhadores de enfermagem no desempenho de seu trabalho, fundamentado na determinação social desse processo. Evidencia as particularidades da relação trabalho-saúde de uma realidade concreta, decompondo e recompondo as intermediações processo de valorização, processo de trabalho, cargas de trabalho e desgaste, o que permitiu explicitar o perfil de morbidade desses trabalhadores. Nesse perfil, os ferimentos pérfuro-cortantes e as doenças ósteo-músculo-articulares aparecem como danos característicos desse grupo de trabalhadores de enfermagem.

  17. Estudio del comportamiento de los recargues multicapas de depósitos soldados de fundición blanca al cromo

    Directory of Open Access Journals (Sweden)

    R. Collazo-Carceller

    2009-05-01

    Full Text Available Se determina la influencia de los parámetros Energía introducida (Hi, Número de capas (Nc y Ancho del depósito (Ad, en la morfología y el incremento de la resistencia al desgaste abrasivo de capas depositadas sobre acero 1020 utilizando el electrodo de fundición blanca al cromo UTP Ledurit – 61. Empleando la microscopia óptica se identificaron y cuantificaron las fases presentes, analizando su efecto en el desgaste. Siendo determinante la influencia de la inclinación de las dendritas y su posición con respecto a 90° en el incremento de la resistencia al desgaste abrasivo. Se caracterizaron los posibles mecanismos de daño superficial provocado por desgaste abrasivo empleando la microscopia electrónica de barrido. Se propusieron modelos lineales para correlacionar la influencia de la cantidad, tamaño, dispersión de los carburos y el ángulo de inclinación de las dendritas, en el incremento de la resistencia al desgaste.The influence of different parameters in layer morphology and abrasion resistance of Fe-Cr-C electrodes UTP Ledurit – 61 on steel 1020 was studied. Introduced Energy (Hi, Number of Layers (Nc, and Deposit Width (Ad were the main parameters considered. The metallographic identification and quantification of metal phases and the determination of their effect in abrasion resistance were made with optical microscopy. The abrasive wear test characterized by scanning electron microscopy, defines a possible mechanism of surface damage. It was found that the angle formed between a normal line to the surface and the dendrite inclination is directly related with the increment of wear resistance. Lineal models that correlate wear resistance with quantity, size, and carbide dispersion and dendrite angle inclination were also developed.

  18. Desgaste profesional en el personal sanitario y su relación con los factores personales y ambientales Burnout syndrome in health workers and relationship with personal and environmental factors

    Directory of Open Access Journals (Sweden)

    Armand Grau

    2005-12-01

    Full Text Available Objetivos: Entre los profesionales sanitarios se han hallado altos índices de desgaste profesional. Nuestro objetivo fue estudiar la prevalencia del síndrome de desgaste profesional en los trabajadores sanitarios hospitalarios, y valorar su relación con los factores personales y ambientales. Métodos: Un total de 2.290 trabajadores sanitarios de 5 hospitales de Girona fueron invitados a participar. Se les administró un cuestionario de elaboración propia, una encuesta del clima organizacional, y el Maslach Burnout Inventory, que incluye tres dimensiones: cansancio emocional, despersonalización y baja realización personal. Resultados: Contestaron la encuesta 1.095 trabajadores (con un 47,8% de participación. Un 41,6% presentó un alto nivel de cansancio emocional, sobre todo los médicos y el personal de enfermería; un 23% tuvo un alto nivel de despersonalización, sobre todo los médicos, y un 27,9% tuvo una baja realización personal, en especial los técnicos y los médicos. Mediante un análisis de regresión logística múltiple, se asoció un alto nivel de cansancio emocional al consumo de tranquilizantes o antidepresivos con asiduidad, mientras que el optimismo y la satisfacción profesional mostraron una asociación inversa. Los años de profesión, el optimismo, valorar como útil el trabajo y percibir que se es valorado por los demás se asociaron inversamente con un alto nivel de despersonalización. La baja realización personal se asoció inversamente con el optimismo, la valoración de la utilidad del trabajo y el equipo de trabajo. Conclusiones: A partir de los resultados obtenidos, recomendamos mejorar el clima organizacional y potenciar el optimismo y la autoestima individual, para disminuir el desgaste profesional en los hospitales.Objectives: High rates of professional burnout syndrome have been found among health service professionals. Our objective was to study the prevalence of burnout syndrome in hospital health

  19. Wear studies in the shearing process by means of irradiated tools; Etudes d'usure dans les operations de cisaillement, au moyen d'outils irradies; Issledovaniya problemy iznosa v protsesse skalyvaniya posredstvom obluchennykh instrumentov; Estudios de desgaste en las operaciones de cizallamiento, realizados con ayuda de herramientas irradiadas

    Energy Technology Data Exchange (ETDEWEB)

    Sata, Toshio; Abe, Kunio; Nakajima, Kiyoshi [Institute of Physical and Chemical Research, Komagome, Bunkyo-Ku, Tokyo (Japan)

    1962-01-15

    pastilles, tandis que la radioactivite des trous variait a peine. Cela montre que l'usure de la matrice peut etre mesuree d'apres la radioactivite des pastilles, et celle du poincon d'apres la radioactivite des trous. On a eu recours a cette methode pour suivre le processus d'usure du poincon et de la matrice en employant differents lubrifiants et differentes toles, ce qui a permis de faire les constatations suivantes: 1. Au debut du poinconnage, le taux d'usure du poincon et celui de la matrice sont tres eleves mais diminuent rapidement, pour devenir finalement stationnaires apres decoupage d'environ 4 a 500 pieces. 2. L'usure du poincon est d'environ 20 % plus forte que celle de la matrice. 3. Les lubrifiants contenant des additifs qui resistent aux pressions extremes, tels que le chlore, le phosphore ou le soufre, reduisent l'usure des outils, tandis que les huiles minerales raffinees n'apportent guere d'amelioration. 4. La plus forte usure des outils se produit lors du poinconnage des toles les plus dures. Cette usure est environ trois fois plus forte pour l'acier inoxydable et environ six fois plus forte pour l'acier riche en silicium que pour l'acier pauvre en carbone. (author) [Spanish] Se ha estudiado el desgaste de las herramientas utilizadas en el corte de laminas metalicas con punzones y matrices de acero rapido irradiados en un reactor. Se recortaron a punzon discos de 10 mm de diametro en laminas de acero pobre en carbono, acero inoxidable y acero al silicio de 0,5 mm de espesor en estado seco y lubricado. Despues del punzonamiento, se midio la radiactividad de los discos y de los orificios. Al reemplazar la matriz radiactiva por otra no irradiada, se detecto escasa actividad en los discos, mientras que la radiactividad de los orificios apenas sufrio variacion. Ello demuestra que el desgaste de la matriz y del punzon pueden medirse en funcion de la radiactividad de los discos y de los orificios, respectivamente. Con ayuda de este metodo, se estudio el desgaste

  20. Microcomputer based sliding regime discrete control for synchronous AC motors Control discreto por microordenador basado en regímenes deslizantes para motores de corriente alterna síncronos

    Directory of Open Access Journals (Sweden)

    Eduardo Palomar–Lever

    2007-12-01

    Full Text Available The basic ideas to design discrete algorithms used to calculate unmeasured mechanical or electrical variables, in order to control electrical motors in mechanical systems are presented. The main point of the paper is to simplify the algorithms by using a linear discrete time model without any variable limitations and to reduce the computing capacity requirements of the controller. Limited references, based on the discrete sliding mode for the exception of the influences of variable limitations, are proposed and designed. The main advantage of the controller presented in this paper is that a large control error does not bestow any problems. In such a case, the system always works in an area without the limitations. Original observation algorithms of both position and rotational velocity for exterior permanent magnet synchronous motors are designed. A computer simulation was performed and the results are presented, showing high dynamic accuracy.Se presentan las ideas básicas para diseñar algoritmos discretos para calcular las variables mecánicas o eléctricas, no medidas sino estimadas, para controlar motores eléctricos en sistemas mecánicos. El objetivo principal de este artículo es simplificar los algoritmos usando un modelo de tiempo discreto lineal sin ninguna limitación en las variables y reducir los requisitos de capacidad informática del controlador. Las referencias limitadas, basadas en el modo deslizante discreto para la excepción de las influencias de limitaciones de las variables, se proponen y diseñan. La ventaja principal del controlador presentada en este artículo es que un error de control grande no causa ningún problema. En dicho caso, el sistema trabaja siempre en un área sin limitaciones. Se diseñan los algoritmos de la observación originales de la posición y de la velocidad rotatoria para el imán permanente exterior de motores síncronos. Se llevó a cabo una simulación en computadora y se presentan los

  1. Fabrication and tribological properties of Al reinforced with carbon fibers

    Directory of Open Access Journals (Sweden)

    Estrems Amestoy, Manuel

    2000-10-01

    Full Text Available The present work studies the manufacturing process of Al reinforced with Carbon Fibres (CF by "Squeeze Casting", establishing the variables for obtaining an acceptable product with little Al4C3 at the interface. Friction and wear tests are performed and the necessary conditions for the formation of a tribofilm are established. The tests show an increasing resistance to abrasion due to their own wear mechanism. Certain design criteria for those components subjected to friction are recommended in order to maximise the mechanical performance of the tribological system.

    Este trabajo estudia el proceso de fabricación de composites Al reforzado con fibras de carbono mediante la técnica ''Squeeze Casting'', estableciendo las variables para obtener un producto aceptable que tenga poca cantidad de Al4C3 en la interfase. Se han realizado ensayos de fricción y desgaste y se han establecido las condiciones necesarias para la formación de la tribocapa. Se muestra la alta capacidad de resistencia a la abrasión de las piezas producidas debido a su propio mecanismo de desgaste y se recomiendan ciertos criterios de diseño para componentes mecánicos con el fin de optimizar las prestaciones mecánicas en un sistema tribológico.

  2. Participação nos lucros ou resultados e banco de horas: intensidade do trabalho e desgaste operário

    Directory of Open Access Journals (Sweden)

    José Augusto Pina

    Full Text Available INTRODUÇÃO: As transformações operadas no processo de trabalho na indústria automobilística no Brasil desde os anos 1990 apontam para o fortalecimento da gestão da força de trabalho como um dos determinantes do processo saúde-doença dos trabalhadores. OBJETIVOS: Discutem-se dois elementos da gestão: a participação nos lucros ou resultados (PLR e o banco de horas (BH e assinala-se a relação de ambos com a intensidade do trabalho e o desgaste operário. Métodos: Apóia-se em revisão bibliográfica e em análise dos acordos coletivos dos metalúrgicos do ABC-SP, entre 2001 e 2008. RESULTADOS: A análise realizada mostrou que a reorganização do tempo de trabalho, o prolongamento da jornada e a manutenção do elevado grau de intensidade do trabalho ocasionados pelo BH e as metas vinculadas à PLR exercem pressão sobre o trabalhador para o aumento quantitativo e qualitativo do trabalho, evidenciando que esses instrumentos gerenciais propiciam a intensificação do trabalho e o desgaste operário. Também afetam drasticamente o tempo de não trabalho fora da jornada, inclusive prejudicando a reposição e o desenvolvimento da capacidade biopsíquica do trabalhador. CONCLUSÃO: A PLR e o BH podem ser caracterizados como uma forma de administração por estresse que eleva e potencializa as cargas de trabalho e o desgaste operário.

  3. Comportamiento del hierro nodular austemperizado en condiciones de corrosión y desgaste // Behavior of austempered ductile iron under wear and corrosion conditions

    Directory of Open Access Journals (Sweden)

    L. Goyos Pérez

    1999-07-01

    Full Text Available Los hierros nodulares en general y los austemperizados en particular han sido usados con cada vez mayor frecuencia debido asus relevantes propiedades mecánicas en comparación con su costo.En el presente trabajo se valora el comportamiento del hierro nodular ante el trabajo en condiciones de desgaste y corrosión,luego de ser sometido a diferentes tratamientos de austemperizado.Fueron usados un hierro nodular aleado con níquel y molibdeno y otro no aleado. Ambos hierros fueron sometidos a diferentestratamientos de austemperización con mantenimientos isotérmicos a temperaturas entre 250°C y 425°C por tiempos entre 15 y180 minutos.Las muestras tratadas fueron sometidas a ensayos de desgaste por fricción en condiciones no lubricadas determinando laspendientes de desgaste uniforme para cada caso. La resistencia a la corrosión fue determinada mediante el métodopotenciométrico usando como medio el jugo de caña sintético.A partir de los resultados obtenidos se valora la influencia de los diferentes tratamientos sobre las propiedades estudiadas y sedeterminan los más efectivos desde el punto de vista técnico económico.Palabras claves: Hierro nodular, corrosión, desgaste, austemperizado.____________________________________________________________________________AbstractNodular irons and particularly austempered ductile iron has been used more and more due to their excellent mechanicalproperties in comparison with their cost.Presently work deals on behavior of nodular iron working under wear and corrosion conditions, after being submitted todifferent austempered treatments.A nodular iron alloyed with nickel and molybdenum were used as well as a not alloyed one. Both irons were treated underdifferent austempered treatment combinations using isothermal maintenance to temperatures between 250°C and 425°C andspending times between 15 and 180 minutes.Samples were submitted to non-lubricated wear using a “pin on disk” method evaluating the

  4. Estudio experimental del desgaste del flanco y de la rugosidad superficial en el torneado en seco de alta velocidad del acero AISI 316L

    OpenAIRE

    Morales Tamayo, Yoandrys

    2014-01-01

    La mejora continua de los procesos de fabricación es fundamental para alcanzar niveles óptimos de productividad, calidad y coste en la producción de componentes y productos. Para ello es necesario disponer de modelos que relacionen de forma precisa las variables que intervienen en el proceso de corte. Esta investigación tiene como objetivo determinar la influencia de la velocidad de corte y el avance en el desgaste del flanco de los insertos de carburos recubiertos GC1115 y GC2015 y en la rug...

  5. Sindrome de desgaste profesional (burnout en médicos especialistas de un hospital universitario, de la ciudad de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Robert Ferrel

    2013-10-01

    Full Text Available ResumenDiversas investigaciones han señalado una estrecha relación entre el síndrome de quemarse por el trabajo o de desgaste profesional (burnout y los problemas de salud, relacionando al burnout como una de las causas del deterioro de las condiciones de trabajo y fuente de la accidentalidad y absentismo laboral, especialmente en profesionales de la salud y la educación. La presente investigación tuvo como objetivo establecer y describir la existencia del síndrome de burnout en médicos especialistas que laboran en un Hospital Universitario de tercer nivel de la Ciudad de Santa Marta, Colombia. La población estuvo conformada por 56 médicos especialistas vinculados a dicha Institución, a los cuales se les aplicó el Maslach Burnout Inventory (MBI, teniendo en cuenta la edad, especialización y tiempo de vinculación. Los datos fueron procesados por el Software SPSS, 15.0v, haciendo uso de la estadística descriptiva para establecer el nivel de burnout en esta población. Se encontró un alto nivel de agotamiento emocional (94,6% en comparación con las otras dos variables, estando la despersonalización (53,6% y la falta de realización personal (53,6 en un nivel medio, estableciéndose la presencia del síndrome de burnout en un nivel medio en los médicos especialistas del Hospital Universitario. Estos resultados concuerdan con otros estudios similares. Los autores recomiendan continuar con otros estudios incluyendo nuevas variables, así como acciones organizacionales y personales para prevenir el estrés laboral fuente del burnout y mejorar la calidad de los servicios de salud en el Distrito de Santa Marta. (DUAZARY 2010, 29 - 40Abstract Various studies have indicated a close relationship between the syndrome of burnout or burnout (burnout and health problems, relating to the syndrome as a cause of deteriorating working conditions and the source of accidents and absenteeism workforce, especially in healthcare and education. This

  6. Effect of the blades and seals system wear on steam turbine efficiency and power; Efecto del desgaste del sistema de alabes y sellos sobre la eficiencia y potencia de las turbinas de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Campos Amezcua, Alfonso; Kubiak Szyszka, Janusz [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    The implementation of a method for steam turbine evaluation through the measured geometry in the flow channel and its operating conditions, is presented. This method, previously developed, allows the identification and quantification of the power and efficiency loss due to the wear of its elements (worn or bent blades, worn seals, deposits, etc.); the benefit that is obtained is a more precise knowledge on the turbine behavior and a basis is acquired to give priority to the maintenance work, from the stand point of energy utilization. In this paper, the power and efficiency loss of a 300 MW steam turbine is located and evaluated, a sensibility analysis is presented for the typical elements that cause the deterioration of the efficiency in this type of turbines. [Espanol] Se presenta la implementacion de un metodo de evaluacion de turbinas de vapor a partir de la geometria medida del canal de flujo y sus condiciones de operacion. Este metodo, previamente desarrollado, permite identificar y cuantificar las perdidas de potencia y eficiencia debido al desgaste de sus elementos (alabes desgastados o doblados, sellos desgastados, depositos, etcetera); el beneficio que se obtiene es un conocimiento mas preciso del comportamiento de la turbina y que se tiene una base para dar prioridad a los trabajos de mantenimiento desde el punto de vista de aprovechamiento de la energia. En este articulo se localizan y evaluan las perdidas de potencia y eficiencia de una turbina de vapor de 300 MW, ademas, se presenta un analisis de sensibilidad para los elementos tipicos que originan el deterioro de la eficiencia en este tipo de turbinas.

  7. Effect of the blades and seals system wear on steam turbine efficiency and power; Efecto del desgaste del sistema de alabes y sellos sobre la eficiencia y potencia de las turbinas de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Campos Amezcua, Alfonso; Kubiak Szyszka, Janusz [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1998-12-31

    The implementation of a method for steam turbine evaluation through the measured geometry in the flow channel and its operating conditions, is presented. This method, previously developed, allows the identification and quantification of the power and efficiency loss due to the wear of its elements (worn or bent blades, worn seals, deposits, etc.); the benefit that is obtained is a more precise knowledge on the turbine behavior and a basis is acquired to give priority to the maintenance work, from the stand point of energy utilization. In this paper, the power and efficiency loss of a 300 MW steam turbine is located and evaluated, a sensibility analysis is presented for the typical elements that cause the deterioration of the efficiency in this type of turbines. [Espanol] Se presenta la implementacion de un metodo de evaluacion de turbinas de vapor a partir de la geometria medida del canal de flujo y sus condiciones de operacion. Este metodo, previamente desarrollado, permite identificar y cuantificar las perdidas de potencia y eficiencia debido al desgaste de sus elementos (alabes desgastados o doblados, sellos desgastados, depositos, etcetera); el beneficio que se obtiene es un conocimiento mas preciso del comportamiento de la turbina y que se tiene una base para dar prioridad a los trabajos de mantenimiento desde el punto de vista de aprovechamiento de la energia. En este articulo se localizan y evaluan las perdidas de potencia y eficiencia de una turbina de vapor de 300 MW, ademas, se presenta un analisis de sensibilidad para los elementos tipicos que originan el deterioro de la eficiencia en este tipo de turbinas.

  8. Determinación del desgaste del componente acetabular en prótesis totales de cadera. // Wear determination of acetabular component in total hip prosthesis.

    Directory of Open Access Journals (Sweden)

    G. García del Pino

    2002-01-01

    Full Text Available En este trabajo se realiza un estudio a través del Método de los Elementos Finitos “MEF” sobre el desgaste del componenteacetabular durante el ciclo de marcha y considerando algunos casos extremos de cargas como subir y bajar escaleras,levantarse de una silla, etc. Utilizando el MEF fueron modelados independientemente los componentes acetabular yfemoral de la prótesis total de cadera y puestos en contacto posteriormente. Fueron estudiadas varias posiciones delacetábulo así como diferentes casos de carga simulando pacientes con diferente peso corporal y actividades físicas. Paraevaluar los resultados se crearon rutinas en lenguaje C que organizaron los mismos para un tratamiento estadísticoposterior.Palabras claves: biomecánica, ortopedia, elementos finitos, modelación, desgaste, prótesis de cadera.___________________________________________________________________________Abstract.A wear study of acetabular component during the marching cycle, considering some extreme loads cases as: ascend anddescend stairways, get up from a seat, etc , by means of Finite Elements Method ( FEM , is carried out. The acetabular andfemoral component of the total hip prosthesis were independently modeled and placed in contact lastly. Several acetabulpositions were studied as well as different load cases, simulating patients with different body weight and different physicalactivities. To evaluate the results routines in C language were created in order to organized the same ones for a laterstatistical treatment.Key words. biomechanics, ortophedy, finite elements, modelation, wear, hip bone prosthesis.

  9. Psychic workloads and strain processes in nursing workers of brazilian university hospitals Cargas psíquicas y procesos de desgaste en trabajadores de enfermería de hospitales universitarios brasileños Cargas psíquicas e processos de desgaste em trabalhadores de enfermagem de hospitais universitários brasileiros

    Directory of Open Access Journals (Sweden)

    Vivian Aline Mininel

    2011-04-01

    Full Text Available Objective: to identify the work process, the psychic workloads and the strains generated in nursing workers. Method: the study was developed in five Brazilian university hospitals. The sample was composed by 62 nursing workers and the data collection was done by focal group technique, followed by the application of a collective inquire. The data were quantitatively described and systematized according to a thematic analysis. Results: the study population represented 35,37% of the hospital workforce in national setting. The workers mentioned are exposure to several kinds of psychic workload and link them to with others workloads, highlighting the strain processes resulting from this kind of workload, such stress, fatigue, complaints of gastritis and headaches. Conclusions: nursing workers are exposed to several workloads in the hospital environment, especially psychic workloads. This exposure starts strain processes that compromise the health and quality of life, signaling the necessity of interventions in this reality.El objetivo de este estudio fue identificar el proceso de trabajo, las cargas psíquicas y los desgastes generados en trabajadores de enfermería. Se trata de un estudio desarrollado en cinco hospitales universitarios brasileños. La muestra fue compuesta por 62 trabajadores de enfermería; la recolección fue realizada por medio de la técnica de grupo focal, seguida de la aplicación de encuesta colectiva. Los datos fueron descritos numéricamente y sistematizados según análisis temático. La población de estudio representó 35,37% de la fuerza de trabajo hospitalario en el escenario nacional. Los trabajadores refirieron exposición a diversos tipos de cargas psíquicas y las relacionaron con otras cargas de trabajo, destacando los desgastes provenientes de este tipo de carga, como estrés, fatiga, gastritis y cefalea. Los trabajadores de enfermería están expuestos a las diversas cargas de trabajo en el ambiente hospitalario

  10. Inteligencia emocional percibida y desgaste laboral en médicos internos de pregrado Perceived emotional intelligence and burnout in undergraduate medicine interns

    Directory of Open Access Journals (Sweden)

    R. Ortiz-Acosta

    2011-03-01

    Full Text Available Objetivo: Analizar la relación entre los niveles de inteligencia emocional percibida y desgaste laboral en médicos internos de pregrado. Sujetos y métodos: Para ello se utilizó la Trait Meta-Mood Scale, que evalúa la inteligencia emocional percibida, y el inventario de burnout de Maslach, en 44 médicos internos de pregrado de tres hospitales de los Servicios de Salud de Sonora. Resultados: El factor de atención emocional se relaciona negativamente con agotamiento. Claridad correlaciona de manera positiva con reparación emocional y realización personal, y de forma negativa con agotamiento y despersonalización. Reparación de las emociones correlaciona de forma negativa con agotamiento y despersonalización, y de manera positiva con realización personal. Los análisis de regresión revelaron que el desgaste laboral del médico de pregrado se explicaba por una baja atención emocional y falta de claridad en sus emociones. Conclusión: Estos hallazgos evidencian que ciertos factores emocionales deben tenerse en cuenta para explicar el desgaste laboral en el médico interno de pregrado.Aim: To analyze the relationship between the levels of perceived emotional intelligence and burnout in undergraduate medicine interns. Subjects and methods: For this, we used the Trait Meta-Mood Scale, which evaluates perceived emotional intelligence, the Maslach Burnout Inventory, in 44 undergraduate interns from three hospitals of Sonora Health Services. Results: The factor of emotional attention is related negatively with exhaustion. Clarity correlates in a positive way with emotional repair and self-fulfillment; and negatively with exhaustion and depersonalization. Emotional repair correlates in a negative way with exhaustion and depersonalization, and positively to self-fulfillment. Regression analyses showed that burnout in undergraduate interns was explained by a low emotional attention and a lack of clarity in their emotions. Conclusion: Those

  11. Características sólido-fluido en el crisol del horno alto según el modelo de desgaste nodal (MDN

    Directory of Open Access Journals (Sweden)

    Martín, R.

    2009-08-01

    Full Text Available The coke porosity is one of the most important variables that can affect the pig iron production and the lining corrosion. Up to now, the existing bibliography about lining corrosion always connects a deeper wear to an increase in the fluid flow (pig iron at the blast furnace hearth. However, there is no evidence of any deterministic model that could link, from the theoretical point of view, the following variables: lining corrosion, porosity of dead coke and flow of pig iron at the hearth. Besides justifying the lining corrosion profiles, the Nodal Wear Model (NWM can be an effective instrument to interpret the coke porosity and the pig iron speed rates that are generated inside the hearth.

    La porosidad del coque aparece como unas de las variables que más pueden afectar a la producción de arrabio y a la correspondiente corrosión de los revestimientos. Hasta el momento, en la bibliografía existente sobre la corrosión de los revestimientos, siempre se asocia un mayor desgaste con el correspondiente incremento del flujo del fluido (arrabio en el crisol. No obstante, no se tiene referencia de ningún modelo determinístico que pudiera relacionar, desde el punto de vista teórico, las siguientes variables: corrosión de los revestimientos, porosidad del coque inactivo y flujo del arrabio en el crisol. El Modelo de Desgaste Nodal (MDN, además de justificar los perfiles de corrosión de los revestimientos a lo largo de la campaña, puede ser un instrumento eficaz para interpretar la porosidad del coque y los gradientes de velocidad del arrabio que se generan dentro del crisol.

  12. Resistencia al cizallamiento de amalgama adherida utilizando dos sistemas adhesivos en dientes temporales in vitro

    OpenAIRE

    Chiappe González, Alezandra; Céspedes Porras, Jacqueline

    2006-01-01

    Objetivo general: determinar in Vitro la resistencia al cizallamiento de dos sistemas adhesivos en restauraciones de amalgama adherida en dientes temporales. Material y Método: se evaluó dos sistemas adhesivos de diferente tipo de curado: Un sistema adhesivo de curado dual (Clearfil Liner Bond 2v) y otro de autocurado (Multilink). Treinta molares libres de caries fueron divididas en dos grupos de 15 cada uno. Se incluyeron las piezas en cilindros de resina acrílica, se desgastó ca...

  13. Ausência de desgaste agudo da musculatura esquelética e cardíaca em atletas amadores de triathlon

    Directory of Open Access Journals (Sweden)

    Maria Fátima Glaner

    2009-01-01

    Full Text Available http://dx.doi.org/10.5007/1980-0037.2009v11n1p37 A creatina quinase (CK e a sua fração músculo-cérebro (CK MB podem estar ligadas a danos no tecido muscular e cardíaco, respectivamente, como conseqüência de exercícios prolongados e intensos. O estudo teve como objetivo verificar se a variação aguda da CK e da CK MB reflete algum risco de desgaste acentuado para a musculatura esquelética e cardíaca, de atletas amadores, após o Ironman 70.3. A amostra foi composta por dez atletas voluntários, masculinos (idade= 34,0 ± 9,2 anos. A amostra de sangue venoso (2mL foi coletada antes e após o Ironman 70.3. Os voluntários completaram o percurso em 5h20min à 6h. A CK e a CK MB foram analisadas pelo método enzimático, usando reagentes Wienner lab, em um espectrofotômetro automático (Targa bt 3000. O teste não paramétrico de Wilcoxon indicou diferenças significativas (p <0,05 entre os períodos pré e pós competição nas variáveis estudadas. Os valores médios foram: CK= 112,23 ± 34,9U/L e 458,0 ± 204,9U/L (Δ%= 418,2; CK MB= 7,4 ± 2,6U/L e 10,8 ± 3,9U/L (Δ%= 153,3, respectivamente, para pré e pós. A variação relativa da CK MB em relação à CK, pré (6,9% e pós competição (2,5%, indicou que este não é um fator tão preocupante durante o exercício extenuante de longa duração, como o Ironman 70.3. Conclui-se que a concentração aguda de CK, logo após o término do exercício extenuante de longa duração, indicou desgaste da musculatura esquelética, porém considerado normal para atletas. Quanto à CK MB, o desgaste da musculatura cardíaca foi inexistente.

  14. Condiciones de trabajo psicosociales y desgaste psíquico en trabajadores de diversos sectores empresariales de Centro-Oriente, Suroccidente y región Caribe en Colombia

    Directory of Open Access Journals (Sweden)

    M. Ángeles Carrión García

    2014-01-01

    Full Text Available Objetivo: Determinar la percepción de trabajadores de distintos sectores empresariales de Colombia sobre los factores psicosociales presentes en su entorno laboral y la relación entre los factores psicosociales nocivos y los síntomas subjetivos y alteraciones de la salud. Materiales y métodos: Estudio no experimental, transversal y cuantitativo. Participaron 370 trabajadores, de diferentes sectores empresariales de Colombia (Centro-Oriente, Suroccidente y región Caribe. Instrumento: batería para el estudio de las condiciones de trabajo de carácter psicosocial (CTCPS-MAC, validada para población iberoamericana, permite evaluar cuatro dimensiones: Contexto de trabajo, Contenido de trabajo, Factores individuales y Desgaste psíquico e incluye catorce factores psicosociales. Los datos se analizaron con IBM SPSS statistics 21. Se realizó análisis bivariado y regresión logística multivariante de factores psicosociales nocivos y desgaste psíquico. Resultados: Los factores formación, baja médica, contexto de trabajo, contenido de trabajo y factores individuales están asociados en este estudio con desgaste psíquico. El contexto de trabajo es la variable que infiere mayor riesgo (p=0.000; Exp (B= 5.355 para provocar desgaste psíquico, seguida de la formación técnica o superior y del contenido del trabajo. Conclusiones: Si bien aquellos trabajadores cuya percepción nociva del contexto de trabajo (interrelación trabajo-vida familiar/personal, cultura de la organización, gestión de la empresa, etc., del contenido de trabajo (concepción tareas, carga y ritmo de trabajo, etc. y los que tienen formación técnica o superior tienen mayor probabilidad de padecer desgaste psíquico, se observan aspectos positivos de las condiciones de trabajo psicosocial y su influencia en los trabajadores y en las organizaciones.

  15. Measurement of the wear rate of cast grinding balls using radioactive tracers; Evaluation de l'usure des boulets pour concasseurs, au moyen des indicateurs radioactifs; Izmerenie skorosti iznosa litykh drobil'nykh sharov pri pomoshchi mechenykh atomov; Medicion de la velocidad de desgaste de bolas trituradoras de acero colado con ayuda de indicadores radiactivos

    Energy Technology Data Exchange (ETDEWEB)

    Keys, J D; Eichholz, G G [Department of Mines and Technical Surveys, Ottawa, ON (Canada)

    1962-01-15

    broyeur ayant une charge normale d'environ 75 tonnes et des echantillons ont ete preleves a des intervalles d'une semaine pour la recuperation des boulets radioactifs. Ces boulets etaient alors inspectes et peses, apres quoi on a pu calculer leur taux d'usure. Cette methode s'est revelee tres pratique. pour l'etude de la resistance des boulets a l'usure dans les conditions habituelles d'utilisation. (author) [Spanish] La velocidad de desgaste de las bolas trituradoras empleadas en los molinos suele ser dificil de determinar durante el funcionamiento de la maquina, y solo se poseen escasos conocimientos acerca de los factores que determinan su vida util. Los autores utilizaron con exito indicadores radiactivos para marcar bolas de acero colado, con miras a obtener informacion sobre su vida util en diversas condiciones de empleo y compararlas con otras bolas de composicion o tipo distintos. Tomaron un juego de bolas de acero marcadas, y observaron su comportamiento a lo largo de varias semanas de empleo en el molino, obteniendo asi datos estadisticos sobre el desgaste y la perdida de peso sufridos. En las pruebas experimentales anadieron {sup 60}Co al metal fundido antes de colarlas bolas y observaron su comportamiento utilizandolas en una mina de hierro y en otra de oro. Emplearon las bolas marcadas en un molino cuya carga normal es de 75 toneladas aproximadamente, y extrajeron semanalmente muestras del contenido de la maquina para separar bolas activas. Examinaron estas y las pesaron, calculando asi su velocidad de desgaste. Este procedimiento se ha revelado como un metodo practico para el estudio de la resistencia al desgaste de las bolas en condiciones industriales. (author) [Russian] Skorost' iznosa drobil'nykh sharov, ispol'zuemykh v sharovykh drobilkakh, obychno trudno poddaetsya opredeleniyu v rabochikh usloviyakh; k tomu zhe malo chto izvestno otnositel'no faktorov, opredelyayushchikh srok sluzhby drobil'nykh sharov. Dlya polucheniya svedenij o sroke sluzhby drobil

  16. Desgaste profesional y caracterización de las condiciones laborales de especialistas y posgrados en Medicina Interna

    OpenAIRE

    Goñi, Mabel; Medina, Fernando; Pintos, Marcos; Blanco, Cecilia; Tomasina, Fernando

    2015-01-01

    Introducción: las condiciones y el medio ambiente laboral deberían ser motivo de preocupación en todos los ámbitos de trabajo y en especial en el sector Salud. El particular interés de su estudio en médicos internistas radica en que están enfrentados a múltiples y exigentes escenarios que los exponen al riesgo de padecer afecciones relacionadas con el trabajo. Objetivo: caracterizar las condiciones de trabajo, identificar los principales factores de riesgo laboral, el impacto en la salud del ...

  17. Prevalencia del síndrome de desgaste profesional (burnout) en odontólogos mexicanos del sector educativo y privado Prevalence of the syndrome of professional exhaustion (burnout) in mexican dentists of the education sector and private

    OpenAIRE

    Enrique Castañeda Aguilera; Javier Eduardo García de Alba García

    2012-01-01

    Objetivo: Determinar la prevalencia del síndrome de desgaste profesional (burnout) en odontólogos del sector educativo y privado. Material y métodos: Estudio observacional, descriptivo y transversal, mediante el censo del personal odontológico de la Zona Metropolitana de Guadalajara, México de la Universidad de Guadalajara y los que ejercen la práctica privada, donde participaron 135 de ellos aplicándoseles una ficha de identificación y el Maslach Burnout Inventory-Human Services Survey en fo...

  18. Desgaste físico e mental de auxiliares de enfermagem: uma análise sob o enfoque gerencial Desgaste físico y mental de auxiliares de enfermería: un análisis bajo el enfoque gerencial Mental and physical stress of auxiliary nurses: analysis of management

    Directory of Open Access Journals (Sweden)

    Moema Miranda de Siqueira

    1995-01-01

    Full Text Available Buscando melhor compreender o trabalho em organizações de saúde. Foi realizada uma pesquisa em hospitais gerais contemplando alguns grupos ocupacionais. Supõe-se que a atividade de lidar com dor, sofrimento e morte interfere na organização, gestão, condições de trabalho e que de maneira geral, expõe os trabalhadores dessas organizações a um desgaste físico e mental intenso. Percebeu-se, no entanto, que tanto as organizações quanto os próprios grupos ocupacionais têm ainda pouca consciência sobre estes problemas, desenvolvendo poucas formas de regulação ou atenuação dos conflitos daí decorrentes. O artigo apresenta uma análise específica sobre o grupo de auxiliares de enfermagem e sugere, a título de conclusivo, algumas medidas que podem melhorar essa situação.Buscando comprender mejor el trabajo en organizaciones de salud, fue realizada una investigación en hospitales generales contemplando algunos grupos ocupacionales. Se supone que una actividad ligada a dolor, sufrimiento y muerte interfiere en la organización, gestión, condiciones de trabajo y que de manera general, expone a los trabajadores de esas organizaciones a un desgaste físico y mental intenso. Se notó también, que tanto las organizaciones como los propios grupos ocupacionales aún tienen escasa conciencia sobre estos problemas, desenvolviendo pocas formas de regulación o atenuación de los conflictos decorrentes. El artículo presenta un análisis específico sobre el grupo de auxiliares de enfermería y sugiere, a título de conclusión medidas que pueden mejorar esa situación.Seeking a better understanding of job stress, auxiliary nurses were evaluated in General Hospitals Belo Horizonte. The emotional stress which accompanies auxiliary nurses caring for the sick and easing physical and mental suffering affects their own mental state and physical health. Elements that cause suffering and diseases can be attenuated or intensified depending on

  19. Wear analysis by applying a pin-disc configuration to phemoral head and acetabular cup Análisis del desgaste de la articulación cabeza femoral–copa acetabular mediante simulación experimental con máquina perno-disco

    Directory of Open Access Journals (Sweden)

    Beltrán-Fernandez Juan Alfonso

    2008-07-01

    Full Text Available This work determines a prosthetic hip system’s life-span, focusing on a Mexican phenotype. The total sliding equivalent distance for the system was determined, as well as the loading regime under which the femoral component and the acetabular cup were subjected in normal operating conditions. An experimental tribology essay was then performed to simulate the wearing of the components in a Pin over Disc machine. This assay (for which the test specimens were manufactured in medical grade stainless steel AISI-ASTM 316L for the femoral component and high density polyethylene for the acetabular cup was aimed at simulating wear conditions involved in 10 years of continuous operation. A numerical simulation of operational conditions (using the finite element method was performedIn for establishing assay loading conditions to accurately determine where the loads should be applied. The tribology assay led to quantifying the volumetric loss of materials for the system being analysed. It can be concluded that the methodology proposed in this work for estimating the life-span of a prosthetic hip system was valid and accurate by comparing the results with those found in the literature. A statistical validation of the proposed method is plaaned for the future. Key words: Design life; femoral component; acetabular cup; Mexican phenotype; pin-disc configuration.Este trabajo presenta un estudio que permite establecer la vida útil esperada de un sistema prostético de cadera para el caso del fenotipo mexicano. En primera instancia se determinó la distancia total equivalente de deslizamiento y las condiciones de carga entre el componente femoral y la copa acetabular bajo condiciones normales de carga. Posteriormente, se desarrolló una simulación experimental para la realización de un ensayo tribológico en una máquina de desgaste del tipo Perno sobre Disco (Pin on Disk, POD. Este ensayo sometió al conjunto fabricado en acero inoxidable AISI

  20. Aplicación del MDN al estudio de la corrosión de los convertidores Peirce - Smith

    Directory of Open Access Journals (Sweden)

    Verdeja, L. F.

    2004-04-01

    Full Text Available The Nodal Wear Model (NWM constitutes a tool of applicable work study the processes of differential corrosion in the Peirce – Smith convertor (PSC with the purpose of reaching significant improvements in duration and productivity of the several alternatives that one could utilize of the coating. For the application of the NWM to CPS is necessary of the knowledge the mechanisms of existent waste and the definition of the corrosion equations. With the NWM the outputs of corrosion in the tuyere zone of CPS are interpreted.

    El Modelo de Desgaste Nodal (MDN constituye una herramienta de trabajo aplicable al estudio de los procesos de corrosión diferencial en los convertidores Peirce - Smith (CPS con el propósito de alcanzar mejoras significativas en duración y productividad de las diferentes alternativas que se puedan manejar del revestimiento. La aplicación del MDN al CPS precisa del conocimiento de los mecanismos de desgaste existentes y la definición de las ecuaciones de corrosión. Con el MDN se interpretan los resultados de corrosión en la zona de toberas del CPS.

  1. Atrito e desgaste de recobrimentos de PET, politeraftalato de etileno, pós-consumo processados por aspersão térmica Friction and wear of a thermal sprayed PET - poly(ethylene teraphthalate coating

    Directory of Open Access Journals (Sweden)

    Rogério A. X. Nunes

    2007-09-01

    Full Text Available A aspersão térmica envolve processos de recobrimentos que podem utilizar materiais cerâmicos, poliméricos, metálicos ou misturas destes. O material a ser depositado é fundido total ou parcialmente. As partículas aquecidas são aceleradas e projetadas em direção a uma superfície devidamente preparada, onde se formam camadas com estrutura lamelar. Os efeitos das variáveis do processo de aspersão, pressão dos gases de combustão, taxa de alimentação e gás de arraste no transporte do material, sobre a resistência ao desgaste e atrito de filmes PET foram investigados. Os recobrimentos de PET foram caracterizados através do desgaste micro-abrasivo, utilizando o ensaio de caloteste, e da medida dos coeficientes de atrito, com o ensaio de pino-sobre-disco. Os valores do coeficiente de desgaste abrasivo e do coeficiente de atrito dos recobrimentos são comparados com os valores da garrafa PET utilizada como referência. Os coeficientes de desgaste encontrados foram similares aos valores de garrafas PET da ordem de 10-5. As análises estatísticas dos resultados deste trabalho indicam que os efeitos das interações das três variáveis, pressão dos gases de combustão, taxa de alimentação e gás de arraste foram significativos para o coeficiente de desgaste e não significativos para o coeficiente de atrito.The thermal spray technique involves coating processes that can use ceramic, polymers, metallic materials or a blend of these. The material to be deposited is melted totally or partially, where the heated particles are accelerated and projected toward a prepared surface forming layers with a lamellar structure. The effect of the spray process parameters such as, combustion pressure, feed rate and carrier gas, on the wear resistance and friction of PET films was evaluated. The PET coatings were characterized by measuring the wear coefficient through the calowear type testing and the friction coefficients using pin-on-disk testing

  2. Wear and superficial roughness of glass ionomer cements used as sealants, after simulated toothbrushing Desgaste e rugosidade superficial de cimentos de ionômero de vidro utilizados como selantes, após escovação simulada

    Directory of Open Access Journals (Sweden)

    Daniela Rios

    2002-12-01

    Full Text Available The purpose of this study was to evaluate, in vitro, the properties (wear and roughness of glass ionomer cements that could influence their indication as pit and fissure sealants. The utilized materials were Fuji Plus, Ketac-Molar and Vitremer (in two different proportions: 1:1 and ¼:1. The resin-based sealant Delton was used as control. By means of an electronic balance (precision of 10-4 g, wear was measured in function of weight loss after simulated toothbrushing. Superficial roughness was determined by means of a surface roughness-measuring apparatus. The results revealed that diluted Vitremer and Fuji Plus were less resistant to toothbrushing abrasion and had the greatest increase in superficial roughness.Although in clinical situations luting or diluted ionomer cements are often utilized as alternatives to resin-based sealants, the resultsof this study revealed that the properties of those cements are worse than those of restorative ionomers, whichpresented results similar to those of the evaluated resin sealant.O presente estudo foi conduzido in vitro com o intuito de constatar as propriedades (desgaste e rugosidade dos CIV, as quais influenciam na sua indicação como material selador de fossas e fissuras. Os materiais empregados foram Fuji Plus, Ketac-Molar e Vitremer (duas proporções: 1:1 e ¼:1. O selante Delton foi controle. A determinação do desgaste foi obtida através da quantidade de massa perdida após a escovação e a rugosidade através da análise quantitativa da superfície. Os resultados mostraram que o Vitremer diluído e o Fuji Plus apresentaram maior grau de desgaste e maior aumento de rugosidade. Apesar de clinicamente se encontrar um maior uso dos ionômeros de vidro cimentantes ou diluídos como forma alternativa para material selador; este trabalho permitiu concluir que estes possuem propriedades bastante inferiores quando comparados aos ionômeros restauradores que, por sua vez, possuem resultados semelhantes

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

    OpenAIRE

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

    2007-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Eduardo C. Bianchi

    2007-06-01

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

  5. 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 ...

  6. 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

  7. Caracterización de las propiedades de resistencia a la oxidación y desgaste de recubrimientos de proyección térmica de alta velocidad para la protección de incineradoras de residuos sólidos urbanos

    Directory of Open Access Journals (Sweden)

    Guilermany, J. M.

    2008-08-01

    Full Text Available High Velocity Oxy Fuel (HVOF Thermal Spray Technology produces coatings with high erosion and corrosion resistance. These E-C processes are the most usual problems of municipal solid waste incinerators plants. This work shows the characterisation of the optimal coatings obtained and a further study of their behaviour under wear, erosion, corrosion and E-C tests. These tests reproduce the process that takes place inside this kind of plants. A Ni-based powder alloy was used as a feedstock material for this study. The results show that spraying gas (Hydrogen or Propylene and different spray parameters give better corrosion or erosion properties. The coatings sprayed by Hydrogen shows better corrosion behaviour. The coatings sprayed by Propylene shows better mechanical and tribological properties. In both cases the Ni based HVOF coatings show good protection behaviour for the exchangers on the MSWI.

    En el presente trabajo se muestra la obtención, mediante la proyección térmica de alta velocidad (HVOF, de recubrimientos que presentan buenas prestaciones para la protección contra los procesos de erosión y oxidación que ocurren en el interior de las plantas incineradoras de residuos sólidos urbanos (IRSU. El artículo presenta la caracterización de recubrimientos HVOF optimizados para esta aplicación, así como un estudio detallado de su comportamiento bajo distintos ensayos de desgaste y corrosión que reproducen estos procesos. A través de la variación del gas combustible y las condiciones de proyección se han obtenido, sobre sustrato de acero al carbono, distintos recubrimientos a partir de un polvo del mismo material base níquel como materia prima. Se demuestra que con la variación de las relaciones de gas y las condiciones de proyección se obtienen pequeñas diferencias de comportamiento a la oxidación y a la erosión, de los recubrimientos. Los recubrimientos obtenidos a través de propileno como gas combustible muestran

  8. Desempeño de insertos de WC recubiertos con nanomulticapas de [TiN/TiAlN]n en el mecanizado del acero endurecido AISI 4340

    Directory of Open Access Journals (Sweden)

    Luis Henry Moreno

    2011-01-01

    Full Text Available En el presente trabajo se muestran los resultados de la resistencia al desgaste de insertos de carburo de tungsteno (WC sin recubrir y recubiertos con multinanocapas de [TiN/TiAlN]n con un espesor total promedio del recubrimiento de 4 ¿m, así como de insertos recubiertos con monocapas comerciales de TiCN-Al2O3-TiN (TINAL. Se realizaron ensayos de vida útil, análisis de temperatura en la zona de corte, mediciones de rugosidad superfi cial sobre la pieza y sobre los insertos en la superfi cie de ataque, análisis de huella de contacto entre viruta-insertos y análisis de composición química (EDS. Los ensayos se realizaron sobre piezas de acero AISI 4340 utilizando régimen de corte de acabado y aplicando altas velocidades de corte (HSC. Los resultados de mecanizado de acero, para un recorrido de 8.000 metros con diferentes insertos de carburo de tungsteno (WC, sin recubrimiento y recubiertos presentaron valores de desgaste de 0,117 mm y 0,138 mm; en relación a los insertos recubiertos con 300 y 200 bicapas de TiN/TiAlN, respectivamente. De igual manera, los insertos recubiertos con TINAL exhibieron valores de desgaste de 0,174 mm. Además, los valores de temperatura en la zona de corte y para una velocidad de corte de 176,6 m/mim fueron de 522,6 oC para los recubrimientos con 300 bicapas, de 721,4 oC para aquellos con 200 bicapas, y de 1.327,6 oC para los insertos recubiertos con TINAL. La disminución de la temperatura en la zona de corte, relacionada con un menor coefi ciente de fricción y una menor fuerza de corte, contribuyeron al alargamiento de la vida útil de los insertos.

  9. Identificación y comparación de síntomas de desgaste físico y mental en árbitros, entrenadores y educadores físicos

    Directory of Open Access Journals (Sweden)

    José Luis Prendas

    2007-12-01

    Full Text Available El propósito del estudio fue identificar y comparar los síntomas de desgaste físico y mental en árbitros y jueces deportivos, entrenadores deportivos y profesores (as de educación física. Se trabajó con un total de 44 sujetos (37,93±11,58 años de edad, de los cuales 14 eran entrenadores, 15 profesores (as de educación física y 15 árbitros o jueces deportivos. A todos los sujetos se les aplicó cuatro instrumentos: Perfil de Estados de ánimo (POMS, Cuestionario de Síntomas de Sobreentrenamiento (CSSE y Medida de Burnout (MB y una entrevista diseñada por los investigadores. Los resultados del estudio mostraron que un 25% de los sujetos estaba en situación de riesgo (3 entrenadores, 5 educadores, 3 árbitros y un 4,5% (1 entrenador y 1 árbitro tenían manifestaciones del burnout. Además, se encontró correlaciones significativas entre cuatro estados de ánimo (depresión, hostilidad, tensión y fatiga, tres síntomas de sobreentrenamiento (fatiga generalizada, disminución de la conducta y deseo sexual y alteraciones musculares y falta de apoyo social e irritabilidad y el puntaje de la Escala de Burnout. Mediante análisis de x2, se mostró que no había relación significativa (x2 =0,169; p>0,05 entre el rol y el riesgo de sufrir burnout. Esto se confirmó mediante regresión logística donde se observó que la posibilidad de estar en riesgo o de sufrir el síndrome de burnout eran similares para los tres roles examinados (1,12 veces si se era entrenador; 1,25 veces si se era árbitro y 0,7 veces si se era profesor de educación física. Mediante análisis de varianza se encontró diferencia significativa según el nivel de riesgo en cuatro estados anímicos (depresión, hostilidad, tensión y fatiga y cuatro síntomas de sobre entrenamiento (fatiga generalizada, falta de apoyo social e irritabilidad, deseo de asilamiento y negativismo y disminución de rendimiento. Los sujetos con riesgo o con burnout, tuvieron puntajes promedio

  10. Influencia del desgaste profesional en el gasto farmacéutico de los médicos de atención primaria Influence of burnout on pharmaceutical expediture among primary care physicians

    Directory of Open Access Journals (Sweden)

    J. Cebrià

    2003-12-01

    Full Text Available Objetivo: Determinar la influencia sobre el gasto farmacéutico por asegurado (GFPA en atención primaria de salud de diversos factores relacionados con las características personales y profesionales de los médicos generales, y su nivel de desgaste profesional. Método: Estudio observacional transversal de 220 médicos de atención primaria de la provincia de Barcelona a quienes, por medio de entrevista directa, se administró un cuestionario validado y estructurado en dos partes: datos generales (sociodemográficos y profesionales, y desgaste profesional (Maslach Burnout Inventory [MBI] en el año 2000. De forma paralela, se solicitaron los datos de gasto farmacéutico de los profesionales participantes en las direcciones de atención primaria correspondientes. Resultados: El gasto farmacéutico (GF medio fue de 264.627,22 euros (intervalo de confianza [IC] del 95%, 252.669,82-276.584,63 y el GFPA fue de 152,36 euros (IC del 95%,145,73-158,99. El estudio pormenorizado de las características sociodemográficas y de actividad de los profesionales mostró una asociación positiva con el GFPA en los siguientes casos: conforme la edad del profesional es mayor, cuando el número de años trabajados en la atención primaria aumenta, cuando la plaza laboral es fija, cuando los profesionales trabajaban en varios centros, si los profesionales no trabajaban en centros acreditados para la docencia, en el ámbito de la práctica urbana, y cuando hay un nivel alto de cansancio emocional. Conclusiones: El médico de familia soporta en mayor o menor intensidad tensiones en diferentes niveles de su actividad asistencial. La acumulación de tensiones va provocando un desgaste emocional que complica la toma de decisiones en el momento de la prescripción farmacéutica, lo que tiende a cerrar un círculo vicioso. De este modo, los profesionales con mayor desgaste profesional pueden, en ocasiones, compensar la falta de recursos psicológicos que esta situaci

  11. Ti, Al

    Indian Academy of Sciences (India)

    In the present study, authors report on the effect that substrate bias voltage has on the microstructure and mechanical properties of (Ti, Al)N hard coatings deposited with cathodic arc evaporation (CAE) technique. The coatings were deposited from a Ti0.5Al0.5 powder metallurgical target in a reactive nitrogen atmosphere at ...

  12. Estudo comparativo da resistência ao desgaste abrasivo do revestimento de três ligas metálicas utilizadas na indústria, aplicadas por soldagem com arames tubulares Comparative study of the wear resistance of three metal cored wire welded coatings used in industry

    Directory of Open Access Journals (Sweden)

    Ricardo Vinícius de Melo Leite

    2009-12-01

    Full Text Available As ligas metálicas aplicadas por soldagem em superfícies, objetivando a proteção contra o desgaste e o conseqüente aumento da vida útil de peças e equipamentos, têm sido utilizadas em larga escala nas indústrias de bens de consumo e nos setores de mineração e sucroalcooleiro. O desgaste abrasivo em peças e equipamentos representa, nestas industriais, um dos principais fatores de depreciação de capital e uma importante fonte de despesas com manutenção. Para a aplicação do revestimento por soldagem, os arames tubulares têm sido uma alternativa cada vez mais viável, devido à sua alta produtividade e qualidade de solda, substituindo, em parte, o uso do eletrodo revestido. O objetivo deste trabalho é fazer um estudo comparativo da resistência ao desgaste abrasivo do revestimento aplicado por soldagem com arames tubulares autoprotegidos de três ligas metálicas utilizadas na indústria, uma do tipo Fe-Cr-C, outra do tipo Fe-Cr-C com adição de nióbio e boro e a terceira, do tipo Fe-Cr-C com adição de nióbio. Os revestimentos anti-desgaste, conhecidos como revestimento duro, foram aplicados em chapas de aço carbono, com os mesmos parâmetros e procedimentos de soldagem. Os corpos de prova foram obtidos por corte e retificação e foram submetidos a ensaios de desgaste abrasivo, em um abrasômero Roda de Borracha, conforme procedimento estabelecido pela norma ASTM G65-91. Os resultados obtidos demonstraram que a liga Fe-Cr-C com adição de Nióbio e Boro apresentou desempenho superior em relação ao desgaste abrasivo.The metal alloys deposited by welding on the components surface, with the objective of protection against wear and the consequent increase in the lifetime of parts and equipments, have been used extensively in the consumer products industry and sectors of Mining and Sugar & alcohol. The abrasive wear on parts and equipments represents one of the main depreciation factors of capital and the major source of

  13. Nitrocarburación mediante el proceso TENIFER QDQ de aceros inoxidables austeníticos estabilizados : caracterización química y estudio de su comportamiento frente al desgaste y la corrosión

    OpenAIRE

    Bellas Muiño, Leonardo

    2016-01-01

    [Resumen]La nitrocarburación en baño de sales se utiliza para mejorar las propiedades tribológicas de los aceros inoxidables. Sin embargo, la aparición de carburos y nitruros de elementos de aleación en la capa externa puede tener efectos contraproducentes para su resistencia a la corrosión. Por este motivo, el proceso TENIFER®QPQ introduce una etapa de oxidación a altas temperaturas con objeto de formar una capa de magnetita (Fe3O4) que incrementa la resistencia a la corrosión...

  14. Effect of the percentage of reinforcement on the wear in the metal matrix composites sintered with abnormal glow discharge; Efecto del porcentaje de refuerzo frente al desgaste en compuestos de matriz metalica sinterizados con descarga luminiscente anormal

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Velasquez, S.; Pineda-Triana, Y.; Aguilar-Castro, Y.; Vera-Lopez, E.

    2016-05-01

    In this study an analysis of the behavior of dry wear coefficient of a Metal Matrix Composite (MMC) in 316 stainless steel reinforced with particles of titanium carbide (TiC) according to ASTM G 99 standards, in a pin-on-disk test. In this research it is tested the effect of the percentage of reinforcement in the MMC manufactured with 3, 6 y 9% (vol.) of TiC, in samples compacted at 800 MPa, generating different values of grain size, hardness and density, they are sintered with abnormal glow discharge, at a temperature of 1200 degree centigrade ±5 degree centigrade, with a protection atmosphere H{sub 2} - N{sub 2} and a permanence time of 30 minutes. According to the results obtained it is concluded that the best condition for the MMC manufacturing, in relation to the reinforcement percentage, is the one obtained when the mixture contains 6% of TiC compacted at 800 MPa. In these conditions, it was obtained: achieving smaller grain size, the greater hardness and the lowest coefficient of friction. In this respect, it was observed that the incorporation of the ceramic particles (TiC) in a matrix of austenitic steel (316) shows significant improvements in the resistance to the wear. (Author)

  15. Behaviour of alloys by abrasive erosion and carbide formation by welding; Comportamiento frente al desgaste abrasivo de las aleaciones con tendencias a la formacion de carburos aplicadas por soldadura

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The abrasion of the mechanic elements for cut and extraction of minerals implies high cost because the replacement of the damaged elements and shutdown of the machines high cost because the replacement of the damaged elements and shutdown of the machines. The present article abstracts the results obtained in a project of investigation where the variables determining the quality of antiabrasive recharges have been obtained, and a method of evaluation of the different products of this type of recharges existing in the market have been evaluated. (Author) 9 refs.

  16. Abrasion Wear Resistance, Hardness and Microstructure of Hard Linings Deposited by Means of a Submerged Arc. Dureza, microestructura y resistencia al desgaste por abrasion de recargues duros depositados con arco sumergido

    Energy Technology Data Exchange (ETDEWEB)

    Paranhos, R; Alcoforado, J M; Castillo, J A; Sauer, A

    1989-01-01

    Consumable materials for submerged arc welding of the types alloyed flux-neutral electrode and neutral flux-alloyed electrode were used to form, through multipass welding, a light alloy hard lining of the C-Mn type on ASTM A36 Type structural steel. Emphasis was put on microstructural characterization of the linings surveyed under electron scanning microscopy, and tests were performed to study their hardness and abrasion wear resistance at low pressures. As a result of these tests, a great influence of welding parameters on hardness and abrasion resistance properties of the combination active flux-neutral electrode was noticed. As the results showed no relationship between the hardness and the abrasion wear resistance of the linings surveyed, an attempt was made to relate the resulting microstructure with their abrasion wear resistance. (Author)

  17. Prevalencia del síndrome de desgaste profesional (burnout en odontólogos mexicanos del sector educativo y privado Prevalence of the syndrome of professional exhaustion (burnout in mexican dentists of the education sector and private

    Directory of Open Access Journals (Sweden)

    Enrique Castañeda Aguilera

    2012-09-01

    Full Text Available Objetivo: Determinar la prevalencia del síndrome de desgaste profesional (burnout en odontólogos del sector educativo y privado. Material y métodos: Estudio observacional, descriptivo y transversal, mediante el censo del personal odontológico de la Zona Metropolitana de Guadalajara, México de la Universidad de Guadalajara y los que ejercen la práctica privada, donde participaron 135 de ellos aplicándoseles una ficha de identificación y el Maslach Burnout Inventory-Human Services Survey en forma auto-administrada. Las estadísticas descriptivas y el análisis inferencial se realizaron con apoyo del SPSS 15.0 y Epi-infoV6.1. Resultados: Se logró el 90,0 % de respuesta. Se detectó una frecuencia del síndrome de desgaste profesional (burnout en el 50,3 % de ellos. Se obtuvieron diferencias significativas en función a ser menor de 40 años de edad. Se observó la correlación negativa entre las subescalas agotamiento emocional y despersonalización y positiva entre la falta de realización personal en el trabajo. Conclusiones: El síndrome de desgaste profesional (burnout es frecuente (50,3 % en los odontólogos, sus principales factores de riesgo: laborar en la práctica privada, el ser mujer, menor de 40 años de edad, sin pareja estable y con más de 15 años con pareja, el no trabajar la pareja, sin hijos, ser especialista, con menos de 10 años de antigüedad laboral y en el puesto actual de trabajo más de 10 años, laborar en el turno matutino, contratación definitiva y el tener otro trabajo. La afectación del agotamiento emocional y la despersonalización se comporta como el síndrome. Los niveles medios de las subescalas se encuentran en general cerca de la normalidad. Se encontró una correlación negativa entre las subescalas agotamiento emocional y despersonalización y positiva entre la falta de realización personal en el trabajo con la presencia del síndrome. Es necesario establecer medidas preventivas o de intervenci

  18. Comportamiento de las herramientas de conformado con recubrimientos TiAlN crecido por Magnetrón Sputtering Tríodo

    Directory of Open Access Journals (Sweden)

    Diana Marcela Devia-Narváez

    2015-01-01

    Full Text Available Esta investigación se enfoca en el análisis tribológico de los recubrimientos de nitruro de titanio aluminio (TiAlN depositad os por la técnica Magnetrón Sputtering Tríodo, cuando se utilizan como ca pa protectora en herr amientas de conformado. El análisis se rea liza a partir de las propiedades microestructurales que influyen direc tamente en el comportamiento tribológico. Se observó que los me canismos de desgaste predominantes en la superficie son la delaminación y la tribo-oxidación; se determinó un incremento en la vida úti l de la herramienta siendo lo s recubrimientos duros u na excelente alter nativa en la industria metalmecánica.

  19. Dureza e resistência ao desgaste da camada de ZrN formada por nitretação a plasma sobre zircônia parcialmente estabilizada com ítria Hardness and wear resistance of the ZrN layer made by plasma nitriding of yttria partially-stabilized zirconia

    Directory of Open Access Journals (Sweden)

    R. Milani

    2010-07-01

    Full Text Available Corpos-de-prova de zircônia parcialmente estabilizada com ítria foram moldados por prensagem uniaxial, sinterizados e nitretados em plasma de micro-ondas à pressão atmosférica. A camada de ZrN sobre zircônia formou-se a uma taxa de 4 µm.min-1, podendo atingir uma espessura de 500 µm. As amostras foram caracterizadas por meio de medidas de dureza e resistência ao desgaste. A superfície nitretada apresentou dureza superior e resistência ao desgaste similar ao substrato de zircônia.Samples of yttria partially-stabilized zirconia were molded by uniaxial pressing, sintered and nitrided in an atmospheric pressure microwave plasma. This procedure leads to the formation of a ZrN layer whose growth rate and thickness reached 4 µm.min-1 and 500 µm, respectively. The samples were characterized by means of hardness and wear resistance tests. The nitrided surface exhibits superior hardness and wear resistance similar to that of the zirconia substrate.

  20. Mechanical and tribological properties enhancement of heat treated AISI 4340 steel by using a TiN/TiAlN multilayer coating system

    Directory of Open Access Journals (Sweden)

    Gilberto Bejarano

    2008-01-01

    Full Text Available Multicapas de TiN/TiAlN (nitruro de titanio/nitruro de titanio aluminio se depositaron por la técnica de la pulverización catódica d.c. reactiva utilizando blancos de titanio y de aluminio de 10 cm de diámetro, con una pureza de 99,9%, en una atmósfera de argón y nitrógeno (Ar/N, aplicando una temperatura de 300°C y una presión de 7x10-3 mbar al sustrato. Como sustratos se utilizaron silicio (100 y acero AISI 4340 tratado térmicamente con una dureza de 54 Rockwell C (HRC, aproximadamente 5,4 GPa. Recubrimientos de TiN/TiAlN con un contenido de Al de 70% y un espesor total de 4 um se investigaron en función del número de multicapas y sus propiedades mecánicas y tribológicas se compararon con las de las muestras de acero sin recubrir. La estructura cristalina de las muestras recubiertas se analizó mediante difracción de rayos X, la morfología y topografía con microscopia electrónica de barrido (SEM y microscopia de fuerza atómica (AFM. La dureza se determinó mediante nanoindentación, mientras que la resistencia al desgaste se caracterizó a través de mediciones de pin on disc. Para las 150 multicapas de TiN/TiAlN se obtuvo un incremento en la dureza y en el módulo de Young de 62% y 70% respectivamente, en relación a las 30 bicapas iniciales, y de 740% y 202% respectivamente, comparado con el acero AISI 4340 sin recubrir. Finalmente, el coeficiente de fricción se redujo de 0,55 a 0,20 y la rugosidad de 60 nm a 3,2 nm para las probetas de acero recubiertas con 150 bicapas de TiN/TiAlN, lo cual condujo a una mayor resistencia al desgaste del sistema de recubrimiento.

  1. Fricción y desgaste en elementos circulares empleados en pasadores // Friction and waste in elements circular employees in pins.

    Directory of Open Access Journals (Sweden)

    D. Alcántara-Borges

    2009-05-01

    Full Text Available El presente trabajo tiene como objetivo establecer el comportamiento de los pasadores fabricadosde acero 45 empleados en las esteras de los equipos de laboreo minero, los cuales por su condiciónde trabajo, se desgastan prematuramente producto de la fricción por rodadura, pero que a la vez,este fenómeno trae consigo el endurecimiento superficial de las capas tratadas térmicamente. Paradar cumplimiento al objetivo se utilizaron probetas de los elementos antes de su puesta en marchay retirado después de su función. Fueron preparadas probetas de 30 x 30 mm cortadas conabundante refrigeración para comprobar su composición química con el empleo del espectrómetrocuántico de masa y su dureza inicial y final, así como probetas de 15 x 15 mm para el análisismicroestructural. Se establece el comportamiento de la estructura cristalográfica del pasadortratado térmicamente antes de ser sometido a carga y la estructura después del período de vidaútil. También con el trabajo se demuestra el endurecimiento del acero por acritud cuando elmaterial es sometido a la fricción por rodadura.Palabras claves: pasadores, fricción, rodadura, análisis microestructural, endurecimiento superficial.______________________________________________________________________________AbstractThe present work has as objective to establish the behaviour of the fabricated pins of steel grade 45used in the mats of mining equipment. Due to its working condition, these pieces prematurely wearaway because of the rolling friction. At the same time, this phenomenon produce a superficialhardening of the outside layers thermally heat treated. To accomplish this aim some samples ofnon-used tubes and some used for a period of time were compared. Samples of 30 x 30 mm, cutwith abundant refrigeration, were used for chemical analysis with the employment of a massquantum spectrometer. The initial and final hardness of the different samples were also measured.Samples of 15 x 15 mm

  2. AL Amyloidosis

    Directory of Open Access Journals (Sweden)

    Desport Estelle

    2012-08-01

    Full Text Available Abstract Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig light chains (LC (most commonly of lambda isotype usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and

  3. Fricción y desgaste de baldosas cerámicas de gres de monococción y de gres porcelánico

    Directory of Open Access Journals (Sweden)

    Rincón, Jesús María

    2005-10-01

    , permiten comprobar que existe un fenómeno de abrasión simultánea cuando se usan puntas de alúmina, mostrando un comportamiento diferente según el tipo de plaqueta ensayada. Para sistematizar estos resultados en función del tipo de material considerado, se ha definido un parámetro de abrasión a partir de las curvas: μ - ciclos (expresados en rpm, lo que puede permitir una mejor clasificación de dichos materiales.

  4. Fatores intrínsecos do custo energético da locomoção durante a natação Factores intrínsecos del desgaste energético de locomoción durante la natación Intrinsic factors of the locomotion energy cost during swimming

    Directory of Open Access Journals (Sweden)

    Fabrizio Caputo

    2006-12-01

    Full Text Available A quantidade de energia metabólica gasta em transportar a massa corporal de um sujeito por unidade de distância tem sido definida como custo energético da locomoção, ou especificamente para natação, o custo de nado. As diferenças no custo de nado entre os indivíduos parecem ser influenciadas por dois principais fatores, a resistência hidrodinâmica e habilidade técnica do nadador. O menor custo de nado apresentado pelas mulheres tem sido atribuído a menor resistência hidrodinâmica decorrente de menor tamanho corporal, maior percentagem de gordura e melhor posicionamento horizontal. Porém, essas diferenças no custo de nado entre homens e mulheres desaparecem quando corrigidos para o tamanho corporal. Em relação às crianças, o maior custo de nado comparado com o dos adultos quando corrigidos para o tamanho corporal pode ser explicado principalmente por menor habilidade técnica apresentada por elas. Para indivíduos com as mesmas características antropométricas, melhor habilidade técnica e maior tamanho da superfície de propulsão, associados a aumento na eficiência propulsiva, podem reduzir o custo de nado. Quando se comparam os diferentes estilos, o mais econômico é o crawl seguido pelo de costas em qualquer velocidade de nado. O borboleta é o estilo menos econômico a baixas velocidades (La cantidad de energía metabólica gastada en transportar la masa corporal de un individuo por unidad de distancia ha sido definida como el desgaste energético de locomoción, o específicamente para la natación, el desgaste de nado. Las diferencias en el desgaste de nado entre los individuos parecen ser influenciadas por dos principales factores, la resistencia hidrodinámica y la habilidad técnica del nadador. El menor desgaste de nado presentado por las mujeres ha sido atribuido a una menor resistencia hidrodinámica proveniente de un menor tamaño corporal, mayor porcentaje de grasa, y mejor posicionamiento horizontal. Sin

  5. Estudo das características de revestimentos poliméricos aplicados por aspersão térmica para proteção contra desgaste e corrosão de substratos metálicos Study of the characteristics of thermally sprayed polymer coatings for wear and corrosion protection of metallic substrates

    Directory of Open Access Journals (Sweden)

    Carlos Roberto Camello Lima

    2012-12-01

    Full Text Available Revestimentos poliméricos vêm sendo crescentemente considerados como solução na proteção de materiais metálicos contra corrosão e desgaste. A tecnologia de aspersão térmica permite a aplicação de polímeros sobre diversos materiais de substrato, em diversas espessuras, para várias condições ambientais. Polímeros depositados por este processo têm potencial, tanto para reduzir custos com materiais, como para melhorar o desempenho do revestimento em ambientes agressivos. Neste trabalho, foram aplicados revestimentos poliméricos poli-éter-éter-cetona (PEEK e Poliamida 12 sobre substratos de aço carbono, utilizando o processo de aspersão térmica a chama de baixa velocidade. Revestimentos de alta qualidade foram obtidos por esta técnica. Foram avaliadas as características dos materiais e dos revestimentos obtidos, especialmente quanto às propriedades mecânicas, de desgaste e corrosão. De acordo com os resultados obtidos, pode-se afirmar que os revestimentos estudados podem ser utilizados com sucesso em aplicações que envolvam desgaste e corrosão, com uma pequena vantagem para o polímero PEEK.Polymer coatings have been widely considered as a solution in the protection of metallic substrates against both wear and corrosion. Thermal spray technology allows the deposition of polymers onto several substrate materials for various thicknesses at several environmental conditions. Thermal sprayed polymers have high potential for material cost reduction as well as to improve coating performance in drastic environments. In this work, poly-ether-ether-ketone (PEEK and Polyamide 12 were flame sprayed on carbon steel substrates. High quality coatings were obtained. Several tests were carried out to evaluate the coatings mainly related to wear and corrosion performance. According to the obtained results, it can be stated that the studied coatings can be successfully used in applications involving wear and corrosion, with a slight edge

  6. Comparative study of the wear resistance of Al2O3-coated MA956 superalloy

    Directory of Open Access Journals (Sweden)

    Canahua Loza, Hugo

    2000-10-01

    Full Text Available Preoxidation of the MA956 superalloy, proposed as a prosthetic biomaterial, generates a compact and inert a-alumina surface layer. The aim of this study is to assess the wear resistance provided by this alumina layer on the MA956 alloy in comparison with the same coated alloy and versus high density polyethylene. Comparative wear tests were carried out in both dry and wet conditions using the couples MA956/MA956, MA956/UHMWPE (ultra high molecular weight polyethylene and 316LVM/UHMWPE. The results corresponding to the couples MA956/MA956, with and without alumina layer, show that the load has more significant effect than the rotation speed on the weight loss and on the roughness. On the other hand the alumina surface layer provides a clear wear protection. The weight losses of the MA956 specimen in this couple are ten times lower when testing under wet conditions than under dry conditions. The MA956/UHMWPE couple behaves much better than the 316LVM/UHMWPE, as it presents the lowest values of friction coefíicient and weight losses of the MA956 specimen. These are only detectable after 70,000 cycles under a 70 MPa contact pressure. This couple offers the best guarantee of a prolonged service life for articulated parts in a prosthesis.

    La superaleación MA956, que se ha propuesto como biomaterial para prótesis osteoarticulares genera, mediante un adecuado tratamiento de preoxidación, una capa superficial, compacta e inerte, de alúmina alfa. El objetivo del presente trabajo es el estudio de la resistencia al desgaste de esta capa de alúmina, cuando se encuentra en contacto con la propia aleación recubierta y con polietileno de alta densidad. Se realizaron ensayos comparativos de desgaste, tanto en seco como en húmedo, con los pares MA956/MA956, MA956/UHMWPE (polietileno de muy elevado peso molecular y 316LVM/UHMWPE. Los resultados obtenidos con el par MA956/MA956, con y sin capa de alúmina, indican que la carga es el factor de mayor

  7. Migrant labor and wear-out in manual sugarcane harvesting in São Paulo, Brazil Trabalho e desgaste de migrantes no corte manual de cana de açúcar no Estado de São Paulo, Brasil

    Directory of Open Access Journals (Sweden)

    Verônica Gronau Luz

    2012-10-01

    trabalhadores tiveram perda significativa de gordura corporal e peso na primeira metade da safra. A maioria ganhou massa magra e os mais velhos na atividade ganharam menos. Dezoito trabalhadores apresentaram valores alterados de Creatina Quinase e quatro tiveram uréia alterada dentre os 24 que cederam sangue. O trabalho no corte de cana gera perda de peso e gordura corporal e aumento de massa magra que se desgasta com a história de trabalho em safras sucessivas. Pode ainda causar alteração de marcadores bioquímicos de inflamação crônica sistêmica. Novos estudos permitirão entender a relação esforço, desgaste, longevidade laboral e saúde no corte de cana.

  8. 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 ...

  9. Influence of silicon content and heat treatment on wear resistance of white chromium cast irons under high speed solidification conditions; Influencia del contenido de silicio y el tratamiento termico en la resistencia al desgaste de fundiciones blancas al cromo en condiciones de rapida solidificacion

    Energy Technology Data Exchange (ETDEWEB)

    Goyo, L.; Varela, A.; Verhaege, M.; Garcia, A.; Mier, J.; Moors, M.

    2012-11-01

    The influence of silicon content and heat treatment on microstructure, abrasive and dry friction wear resistance of a 3 % C, 12 % Cr cast iron, under fast solidification conditions is studied. The fast solidification condition diminishes the carbide volume and the silicon content increases their dispersion and finesses. All matrixes obtained were perlitics, whit different finesses. No intermediate transformation products were noticed. Hardness had little variation. Austenization treatment show little effectivity, with tendency to increase wear in reference to as cast and maintenance treatments. Behavior under dry friction and abrasive wear were similar under test conditions applied whit more influence of carbide morphology in the abrasive wear conditions. (Author) 32 refs.

  10. Estudo comparativo da reabsorção radicular apical em pacientes bruxônomos e pacientes sem sinais clínicos de desgaste dentário Comparative study of apical root resorption in patients whith bruxism and without clinical signs of dental wearing

    Directory of Open Access Journals (Sweden)

    Rebeca Odebrech

    2004-05-01

    Full Text Available A reabsorção radicular, assim como o bruxismo, são temas amplamente abordados na literatura, contudo, a associação dos mesmos ainda permanece pouco documentada. Desse modo, esta pesquisa objetiva comparar pacientes portadores de bruxismo e pacientes sem sinais clínicos de desgaste dentário em relação à quantidade de reabsorção radicular apical nos incisivos superiores. Para tanto foram avaliados clínica e radiograficamente 64 pacientes, perfazendo um total de 256 incisivos acompanhados. Os resultados demonstram que há uma correlação positiva entre bruxismo e reabsorção radicular.Root resorption and bruxism are largely study in literature. However their association still remains few documented. The aim of this study is compare the quantity of apical root resorption in upper permanent incisors in patients with bruxism and without clinical signs of dental wearing. 64 patients (256 incisors were evaluated clinical and radiografically. The results shows the correlation between bruxism and root resorption.

  11. /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.

  12. 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.

  13. Lou Gehrig's Disease (ALS)

    Science.gov (United States)

    ... disease. Who Gets ALS? Although this disease can strike anyone, ALS is extremely rare in kids. According ... home to provide care that the family cannot handle alone. Living With Lou Gehrig's Disease Living with ...

  14. Aussprache als motorische Fertigkeit

    DEFF Research Database (Denmark)

    Bonner, Maria

    2013-01-01

    Authentische Aussprache gilt im Fremdsprachenunterricht als schwer erreichbares Ziel, fremdsprachlicher Akzent wird als nahezu unvermeidbar gesehen. Weder die Hypothese einer kritischen Periode für den Erwerb einer authentischen Aussprache noch das Konzept der Fossilierung im Sprachlernprozess...

  15. Amyotrophic lateral sclerosis (ALS)

    Science.gov (United States)

    Lou Gehrig disease; ALS; Upper and lower motor neuron disease; Motor neuron disease ... One out of 10 cases of ALS is due to a genetic defect. The cause is unknown in most other cases. In ALS, motor nerve cells (neurons) waste away ...

  16. 143 - 148_Makeri et al.

    African Journals Online (AJOL)

    USER

    2015-06-01

    Jun 1, 2015 ... Yuan et al., 2003), antimicrobial activity (Sundarrao et al., 1993; Betancur-Galvis et al., 1999; Takashi et al., 2006), anti-parasitic, anti-malarial activities (Alali et al., 1998; Jaramillo et al., 2000; Luna et al.,. 2005). This study evaluates the antibacterial activity of extract of stem –bark and leaf extracts of Annona.

  17. 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

  18. Pornographie als Metapher

    Directory of Open Access Journals (Sweden)

    Caroline Schubarth

    2010-02-01

    Full Text Available In diesem Artikel werden unterschiedliche metaphorische Verwendungen des Pornografiebegriffs und deren Implikationen untersucht. Während die Existenz von Pornografie der feministischen Anti-Porno-Bewegung als Erklärung für die anhaltende Diskriminierung von Frauen in westlichen Gesellschaften dient, nutzen rechtskonservative Kräfte den Pornografievorwurf als Rechtfertigung für die Zensur von als deviant empfundenen Identitäten und sexuellen Praktiken.

  19. Los procesos de estrés laboral y desgaste profesional (burnout: diferenciación, actualización y líneas de intervención Stress and burnout at work: differences, updates and lines of intervention

    Directory of Open Access Journals (Sweden)

    Raquel Rodríguez Carvajal

    2011-01-01

    Full Text Available El escenario laboral actual marcado por la globalidad y la inestabilidad genera unas condiciones que hace que muchos profesionales experimenten frustración y un alto nivel de tensión emocional, que conlleva un aumento de los niveles de estrés laboral y del desgaste profesional. La importancia del estudio del estrés laboral y el burnout ha incrementado en los últimos años la productividad científica en estos temas. Se ha realizado por ello una revisión de la literatura para ofrecer una visión global y actualizada de ambos procesos. Se muestran los principales modelos y las variables de estudio vigentes así como las principales líneas más actuales de intervención que se vienen desarrollando hasta la fecha.Today´s workplace is constantly changing. Organizations are confronted with multiple challenges, brought by globalization and instability. This situation causes many professionals to experience frustration and a high level of emotional tension, which may easily lead to increased levels of occupational stress and burnout. The importance of studying occupational stress and burnout has led to an increase in the scientific productivity in these areas during the last years. The present literature review provides an overview and update of both occupational stress and burnout processes. The main models are presented as well as the current variables in study. The main lines of intervention that have been developed to date are also reviewed.

  20. The use of radioactive tracers in lubrication and wear research; Emploi des indicateurs radioactifs dans les recherches sur la lubrification et l'usure; Ispol'zovanie mechenykh atomov pri issledovanii voprosov smazki i iznosa; Utilizacion de los indicadores radiactivos en los estudios sobre la lubricacion y el desgaste

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, R B; Grunberg, L; Milne, A A; Wright, K H.R. [Lubrication, Wear and Mechanical Engineering Aspects of Corrosion Division, National Engineering Laboratory, Thorntonhall, Glasgow (United Kingdom)

    1962-01-15

    deux surfaces est etudiee en fonction de la vitesse de deplacement, de la rugosite des surfaces en contact et de la presence de lubrifiants. Pour etudier la repartition de l'usure, on insere des chevilles de fonte contenant de l'Ir{sup 192} dans les chemises d'un moteur-diesel et l'on preleve des echantillons d'huile dont on mesure la radioactivite. On utilise des particules radioactives de fer et d'oxyde de fer pour etudier leur role dans le processus d'usure. La reactibilite de surfaces metalliques qui ont travaille est etudiee a l'aide d'acide stearique marque au C{sup 14} et de S{sup 35} en solution. La vitesse de reaction des produits ajoutes a l'huile d'engrenages est etudiee au moyen de courtes impulsions electriques que l'on envoie dans des fils metalliques immerges dans des solutions de composes marques au S{sup 35} et au P{sup 32}. La constitution de pellicules retardant l'usure a la surface des dents d'engrenages est etudiee en fonction de la pression de friction, de la vitesse et du temps de fonctionnement. Un probleme commun a nombre de ces applications est celui de la conversion de l'activite mesuree en quantites absolues de matieres presentes dans les pellicules de surface ou dans les dechets resultant de l'usure. Des methodes de calibrage ont ete mises au point a cette fin. (author) [Spanish] La solucion de muchos de los problemas de lubricacion y desgaste requiere el estudio de procesos que ocurren en escala muy pequena a los que pueden aplicarse con exito metodos de gran sensibilidad basados en el empleo de indicadores radiactivos. Los autores citan varios ejemplos de estas aplicaciones, realizadas en la Lubrication and Wear Division del National Engineering Laboratory (Reino Unido). La memoria estudia la relacion cuantitativa entre la transferencia de metal y la friccion en las capas limite, en funcion de la velocidad de deslizamiento, de la rugosidad de la superficie y de la presencia de lubricantes. A fin de estudiar la distribucion del desgaste

  1. An electrochemical investigation of the corrosion behavior of Al-Si-Cu hypereutectic alloys in alcoholic environments

    Directory of Open Access Journals (Sweden)

    Traldi, S. M.

    2003-12-01

    Full Text Available Al-Si-Cu hypereutetic alloys produced by spray forming are mostly used in the automotive industry, especially for cylinder liners. They have the advantage of low weight associated with low coefficient of thermal expansion and excellent mechanical properties - mainly wear resistance at high temperatures. The corrosion resistance of these alloys in fuels, particularly alcoholic media, however is not yet known. In this investigation, electrochemical impedance spectroscopy (EIS and potentiodynamic polarisation have been used to evaluate the corrosion resistance of a hypereutectic Al-Si-Cu alloy in alcoholic environments. The EIS tests were carried out in pure ethanol, and ethanol with small additions (1 mM of acid and chloride, to investigate the effect of these contaminants on corrosion resistance. The corrosion resistance of a grey cast iron has also been evaluated in pure ethanol for comparison. The Al-Si-Cu alloy showed high corrosion resistance in pure ethanol, far superior to that of grey cast iron in the same medium.

    Aleaciones hipereutécticas producidas por conformación por spray son muy empleadas en la industria automovilística, especialmente en los revestimientos de los cilindros. Tienen la ventaja de añadir menos peso con bajo coeficiente de expansión térmica y excelentes propiedades mecánicas, sobre todo resistencia al desgaste en altas temperaturas. Todavía, la resistencia a la corrosión de estas aleaciones en combustibles no es conocida. En este estudio fueron utilizadas las técnicas de espectroscopia de impedancia electroquímica y polarización potenciodinámica, para evaluar la resistencia a la corrosión de una aleación hipereutéctica Al-Si-Cu en medio alcohólico. Las pruebas fueron conducidas en etanol puro y etanol con pequeñas adiciones (1 mM de ácido y cloruro, con la finalidad de investigar el efecto de estos contaminantes en la resistencia a la corrosión. Hierro fundido gris, también fue

  2. Aventuras da Significação: Bakhtin e Eco à procura do signo deslizante

    Directory of Open Access Journals (Sweden)

    Humberto Ivan Keske

    2008-12-01

    Full Text Available The present work operatons on the possibility of articulation between the conception of enunciation context introduced by Bakhtin and Voloshinov (1997 and the notion of text produced by Umberto Eco (1986. With this goal in mind, a dialogue between some elements presented by both Bakhtin and Voloshinov (1997 and Eco (1986 will be attempted, in order to re-adress the issue of transformation of textual meaning caused by change in enunciation context. From the intertext process and from context influence emerge different narratives which interlace themselves to compose the multiplicity of tissues that complete, collide, confront and veil themselves for the establishing, construction and updating of one or several meanings.

  3. Efeito do consumo excessivo de oxigênio após exercício e da taxa metabólica de repouso no gasto energético Efecto del consumo excesivo de oxígeno después del ejercicio y de la tasa metabólica de reposo en el desgaste energético Effects of excess post-exercise oxygen consumption and resting metabolic rate in energetic cost

    Directory of Open Access Journals (Sweden)

    Giselle Foureaux

    2006-12-01

    Full Text Available A crescente prevalência de obesidade e sobrepeso ressalta a necessidade de intervenções para reverter esse quadro. Nesse contexto, a atividade física pode contribuir com um efeito duplo, por meio de mudanças fisiológicas agudas e crônicas: na primeira condição encontra-se o gasto energético do exercício e recuperação (EPOC - consumo excessivo de oxigênio após o exercício, e na segunda encontra-se a taxa metabólica de repouso (TMR. Dessa forma, o objetivo deste trabalho de revisão foi investigar o efeito do EPOC e da TMR como coadjuvantes nos programas de emagrecimento, buscando discutir os divergentes resultados encontrados na literatura, no que diz respeito à magnitude e duração do EPOC, bem como discutir o efeito do exercício na TMR. Os estudos demonstram, de forma geral, que o exercício de maior intensidade é capaz de promover maior EPOC, se comparado com um exercício de intensidade menor e, quando comparam o exercício resistido com o aeróbio, verifica-se maior EPOC no primeiro. Em relação às alterações da TMR, os resultados agudos mostram aumento significativo, porém os resultados em longo prazo são mais discrepantes, devido à dificuldade de mensurar essa variável, sem superestimá-la. Concluindo, a literatura aponta que a periodização de um treinamento que possa maximizar tanto o EPOC quanto a TMR podem ser importantes fatores para o emagrecimento e, embora, o custo energético dessas variáveis em uma sessão de exercício se mostre pequeno, em longo prazo poderá ser bastante significativo. No entanto, novos estudos deverão ser realizados com o intuito de confirmar essas evidências.La creciente prevalencia de la obesidad y el sobrepeso resalta la necesidad de intervenciones para reverter ese cuadro. En ese contexto, la actividad física puede contribuir con un doble efecto, por medio de cambios fisiológicos agudos y crónicos: en la primera condición se encuentra desgaste energético del ejercicio

  4. Alles is al uitgevonden

    NARCIS (Netherlands)

    J.G.M. van Marrewijk (Charles)

    1996-01-01

    textabstractDe voordelen van vrijhandel zijn zeer beperkt, al-thans als we de empirische schattingen van vooraanstaande economen en internationale organisaties mogen geloven. Zo worden de voordelen van liberalisatie voor de Europese Unie geraamd op ongeveer 0,5% van het bnp 1. De door het IMF

  5. Lukman et al. (5)

    African Journals Online (AJOL)

    DELL

    1 Civil Engineering Department, Obafemi Awolowo University, Ile-Ife- Nigeria and Corresponding author. 2Department of Water Resources and Environmental Engineering, Ahmadu Bello University, Samaru, Zaria- Nigeria s Department of Civil Engineering, University of Hafr Al-Batin, Hafr Al-Batin, Saudi Arabia.

  6. Interview als Text vs. Interview als Interaktion

    Directory of Open Access Journals (Sweden)

    Arnulf Deppermann

    2013-09-01

    Full Text Available Das Interview ist nach wie vor das beliebteste sozialwissenschaftliche Verfahren des Datengewinns. Ökonomie der Erhebung, Vergleichbarkeit und die Möglichkeit, Einsicht in Praxisbereiche und historisch-biografische Dimensionen zu erhalten, die der direkten Beobachtung kaum zugänglich sind, machen seine Attraktivität aus. Zugleich mehren sich Kritiken, die seine Leistungsfähigkeit problematisieren, indem sie auf die begrenzte Reichweite der Explikationsfähigkeiten der Befragten, die Reaktivität der Erhebung oder die Differenz zwischen Handeln und dem Bericht über Handeln verweisen. Im Beitrag wird zwischen Ansätzen, die das Interview als Text, und solchen, die es als Interaktion verstehen, unterschieden. Nach dem Text-Verständnis werden Interviews unter inhaltlichen Gesichtspunkten analysiert und als Zugang zu einer vorgängigen sozialen oder psychischen Wirklichkeit angesehen. Das Interaktions-Verständnis versteht Interviews dagegen als situierte Praxis, in welcher im Hier und Jetzt von InterviewerInnen und Befragten gemeinsam soziale Sinnstrukturen hergestellt werden. Anhand ubiquitärer Phänomene der Interviewinteraktion – Fragen, Antworten und die Selbstpositionierung von InterviewerInnen und Befragten – werden Praktiken des interaktiv-performativen Handelns im Interview dargestellt. Ihre Relevanz für die Interviewkonstitution und ihre Erkenntnispotenziale für die Interviewauswertung werden aufgezeigt. Es wird dafür plädiert, die interaktive Konstitutionsweise von Interviews empirisch zu erforschen und methodisch konsequent zu berücksichtigen. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1303131

  7. "Estudio tribologico de aceros para moldes. Aplicacion al moldeo por inyeccion de polibutilentereftalato reforzado con fibra de vidrio"

    Science.gov (United States)

    Martinez Mateo, Isidoro Jose

    fabricacion del molde, tienen una gran influencia sobre su comportamiento en servicio a lo largo de la vida util del molde. En la primera parte del presente estudio, a partir de ensayos punzon sobre disco, se ha determinado la relacion entre la resistencia al desgaste y la dureza de aceros para moldes obtenidos a partir de bloques de gran espesor, estudiando los principales mecanismos de desgaste que tienen lugar. A continuacion, con el fin de determinar el dano superficial que sufren los aceros para moldes en condiciones reales de inyeccion, se han estudiado distintos tipos de aceros utilizados comercialmente en moldes de inyeccion de polimeros y materiales compuestos, seleccionando las condiciones de operacion para determinar la variacion de la rugosidad superficial del acero en funcion del material inyectado, del numero de operaciones sucesivas de inyeccion y de la orientacion del flujo de inyeccion, mediante tecnicas de perfilometria optica y microscopia electronica de barrido. Ademas del dano superficial sufrido por el acero con el numero de piezas inyectadas, tambien se ha determinado la evolucion de la rugosidad superficial de los materiales inyectados, polibutilentereftalato (PBT) puro y materiales compuestos derivados de PBT por adicion de un 20 o un 50% en peso de fibra de vidrio. En el caso de las piezas inyectadas, se ha caracterizado su microestructura en funcion del flujo de inyeccion y de la densidad de fibra, se han determinado sus propiedades termicas y dinamico-mecanicas, asi como la variacion de la rugosidad superficial de las piezas inyectadas con el numero de operaciones de inyeccion y con la geometria de las distintas secciones de las piezas. Finalmente, se ha evaluado la resistencia a la abrasion de PBT reforzado con un 50% de fibra, en funcion del numero de piezas inyectadas y de la direccion de rayado con respecto a la orientacion del flujo de inyeccion.

  8. Universitat popular al Cabanyal

    OpenAIRE

    Ribés Granell, Juan Miguel

    2012-01-01

    La intención es dotar al barrio de un gran espacio verde y de un edificio de interés para los vecinos que enriquezca al Cabanyal, ya que actualmente se encuentra en proceso de degradación. Se pretende desarrollar un proyecto que signifique una mejora en la predisposición del visitante, cubriendo sus necesidades. Al mismo tiempo, se busca crear un espacio arquitectónico que mejore la relación entre las actividades que incluye y su entorno. El proyecto está condicionado por cuatro aspectos fund...

  9. Advanced Light Source (ALS)

    Data.gov (United States)

    Federal Laboratory Consortium — The Advanced Light Source (ALS), a world leader in soft x-ray science, generates light in the wavelengths needed for examining the atomic and electronic structure of...

  10. Taiwo et al (15)

    African Journals Online (AJOL)

    Timothy Ademakinwa

    geometric rise in preference for commercial aquaculture .... content, malondialdehyde level and lipid content of the muscle of the .... other researchers on the gilthead sea bream (Mnari et al., 2007), the .... 23, Orlando, Florida, USA, pp. 18–28.

  11. Okusanya et al (5)

    African Journals Online (AJOL)

    DELL

    rainfall and number of days with rain per month were obtained from Meteorological Institute, Oshodi, Lagos- ... Central and South America, Australia, West. Indies, Africa, (Orwa et al., 2009) and in Florida .... dominant forest tree species. In this ...

  12. Initial Symptoms of ALS

    Science.gov (United States)

    ... have trouble grasping a pen or lifting a coffee cup, while another person may experience a change ... Start your own fundraising event & help create a world without ALS Start an Event Site Map | Press ...

  13. ALS (Amyotrophic Lateral Sclerosis)

    Science.gov (United States)

    ... FDA) has approved the drugs riluzole (Rilutek) and edaravone (Radicava) to treat ALS. Riluzole is believed to ... reverse the damage already done to motor neurons. Edaravone has been shown to slow the decline in ...

  14. Amyotrophic Lateral Sclerosis (ALS)

    Science.gov (United States)

    ... found for ALS. However, the drugs riluzole and edaravone have approved by the Food and Drug Administration ( ... 2-3 months but does not relieve symptoms. Edaravone can slow the clinical decline in daily functioning ...

  15. Obuotor et al (16)

    African Journals Online (AJOL)

    DELL

    fractions and essential oils from the leaves of Eugenia uniflora were investigated on some multidrug resistant pathogens. ... et al., 1987), a reduction in blood pressure measured ..... from E. uniflora suggests high efficacy against this bacterium.

  16. Fakinle et al (11)

    African Journals Online (AJOL)

    DELL

    management issues; there is however a concern about air emissions from the ... poses risks to humans and animals through ... Nigeria have focused on cement industries. (Adejumo et al. ... based MCA which controls the sample holder and.

  17. Ogunyemi et al (17)

    African Journals Online (AJOL)

    DELL

    The results of physicochemical analysis revealed that the concentrations of ... scientific basis for regulating the discharge of potentially ... method for genotocity evaluation using Allium cepaand it ..... al., 2013). National agency for food and drug.

  18. Omotayo et al (4)

    African Journals Online (AJOL)

    DELL

    using biochemical technique and API 20E identification system. The isolates were .... sulphate, phosphate, ammonia and appearance. Heavy metals ... technique as described by Collee et al. (1989) was ..... enzymatic methods. Water Res. 36,.

  19. David et al (12)

    African Journals Online (AJOL)

    DELL

    larger mesophyll cells, xylem tissues, vascular bundles and bundle sheaths than other cultivars. Thus, larger ... mechanism to cope with drought stress. There was an ... where solar radiation is intense (Løe et al., 2007). Most ecological studies ...

  20. Cartas al editor

    Directory of Open Access Journals (Sweden)

    Facultad de Medicina Revista

    1995-10-01

    Full Text Available Con respecto al ensayo "Evaluación del aprendizaje en la educación superior" de la Dra. Análida Pinilla / Ciencia y conciencia en la medicina colombiana / Farmacovigilancia: Una necesidad urgente

  1. Kulturmorphologie als Zivilisationskritik

    DEFF Research Database (Denmark)

    Peters, Rikke Alberg

    2010-01-01

    Der Untergang des Abendlandes wird oft als dasjenige Werk betrachtet, das am tiefsten die national gefärbte Gegenüberstellung von Kultur und Zivilisation in der Zwischenkriegszeit geprägt und propagiert hat. Wie auch bei anderen Autoren der Konservativen Revolution, vor allem bei Thomas Mann und...... Arthur Moeller van den Bruck, tritt der Begriff ‚Kultur’ bei Spengler als normativer Wertbegriff auf, der im Kontrast zu einer degenerierten und seelenlosen Zivilisation steht....

  2. 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.

  3. Pornographie als Metapher

    Directory of Open Access Journals (Sweden)

    Caroline Schubarth

    2010-03-01

    Full Text Available In diesem Artikel werden unterschiedliche metaphorische Verwendungen des Pornografiebegriffs und deren Implikationen untersucht. Während die Existenz von Pornografie der feministischen Anti-Porno-Bewegung als Erklärung für die anhaltende Diskriminierung von Frauen in westlichen Gesellschaften dient, nutzen rechtskonservative Kräfte den Pornografievorwurf als Rechtfertigung für die Zensur von als deviant empfundenen Identitäten und sexuellen Praktiken.This article examines different metaphorical uses of the term pornography and the resulting implications. While the existence of pornography for the feminist anti-porno movement serves as factor in the continuing discrimination of women in western societies, conservative powers on the right use the allegation of pornography as a justification for censorship of those identities and sexual practices deemed deviant.

  4. Effect of microstructure and microhardness on the wear resistance of zirconia-alumina, zirconia-yttria and zirconia-ceria coatings manufactured by atmospheric plasma spraying; fecto de la microestructura y de la microdureza sobre la resistencia al desgaste de recubrimientos elaborados por proyeccion termica por plasma atmosferico a partir de circona-alumina, circona-itria y circona-ceria

    Energy Technology Data Exchange (ETDEWEB)

    Giovanni Gonzalez, A.; Ageorges, H.; Rojas, O.; Lopez, E.; Milena Hurtado, F.; Vargas, F.

    2015-10-01

    The effect of the structure and microhardness on the wear resistance of zirconia-alumina (ATZ), zirconia-yttria (YSZ) and zirconia-ceria (CSZ) coatings manufactured by atmospheric plasma spraying was studied. The microstructure and the fracture on the cross section of the coatings were analyzed using Scanning Electron Microscopy, the phases were identified using X-Ray Diffraction, the microhardness was measured by Vickers indentation and the wear resistance was evaluated by ball on disc test. The results showed that zirconia-alumina coating exhibits the best performance in the wear test. This behavior is closely related to their microstructure and higher microhardness, despite of its significant quantity of the monoclinic zirconia phase, which has lower mechanical properties than tetragonal zirconia phase. Tetragonal zirconia phase was predominant in the zirconia-yttria and zirconia-ceria coatings and despite this behavior; they did not have a good performance in the wear tests. This low wear resistance was mainly influenced by the columnar structure within their lamellae, which caused a greater detachment of particles in the contact surface during the ball-disc tests, increasing its wear. (Author)

  5. Application of a TiAIN coating for the increase wear resistance of a passage floodgate manufactured in steel T9; Aplicacion de un recubrimiento de TiAIN para el incremento de la resistencia al desgaste de una compuerta de paso fabricada en acero T9

    Energy Technology Data Exchange (ETDEWEB)

    Montes de Oca, J.; Gonzalez, H. J. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, IPN, Unidad Altamira, Km. 14.5 Carretera Tampico-Puerto industrial Altamira, 89600 Altamira, Tamaulipas (Mexico); Solis, E. [Hy-Teck Fluid Power, Blvd. A. Lopez Mateos No. 310, Col. Nuevo Aeropuerto, 89337 Tampico, Tamaulipas (Mexico); Moreno, J. [Departamento de Ingenieria Metalurgica, Escuela Superior de Ingenieria Quimica e Industrias Extractivas, IPN, UPALM Unidad Zacatenco, 07730 Mexico D. F. (Mexico); Munoz S, J. [Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, 76230 Santiago de Queretaro, Queretaro (Mexico)], e-mail: jmontedeocav@ipn.mx

    2009-07-01

    The present work reports a study to increase wear resistance of a ball passage floodgate (steel type T9) trough the application of a thick film (coating). This study have included a material and process selection, synthesis of the coating on steel plates as substrates and spherical device, assembling of the coated floodgate on the ball valves, and finally an evaluation of the valves in the process of a thermoelectric power station. Taking into account the different requirements, a TiAIN coating prepared by cathodic arc evaporation was finally retained. The crystal structure, morphology and chemical composition of the coating were evaluated by x-ray diffraction (XRD) and scanning electron microscopy equipped with an energy dispersive spectrometer (SEM-EDS). Finally, mechanical properties such as hardness and Young modulus were determined by nano indentation. (Author)

  6. Wear resistance of Fe-Nb-Cr-W, Nb, AISI 1020 and AISI 420 coatings produced by thermal spray wire arc; Resistencia al desgaste de recubrimientos Fe-Nb-Cr-W, Nb, AISI 1020 y AISI 420 producidos por proyeccion termica por arco electrico

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Covaleda, E. A.; Mercado-Veladia, J. L.; Olaya-Florez, J. J.

    2013-07-01

    The commercial materials 140MXC (with iron, tungsten, chrome, niobium), 530AS (AISI 1015 steel) and 560AS (AISI 420 steel) on AISI 4340 steel were deposited using thermal spray with arc. The aim of work was to evaluate the best strategy abrasive wear resistance of the system coating-substrate using the following combinations: (1) homogeneous coatings and (2) coatings depositing simultaneously 140MXC + 530AS and 140MXC + 560AS. The coatings microstructure was characterized using Optical microscopy, Scanning electron microscopy and Laser con focal microscopy. The wear resistance was evaluated through dry sand rubber wheel test (DSRW). We found that the wear resistance depends on the quantity of defects and the mechanical properties like hardness. For example, the softer coatings have the biggest wear rates and the failure mode was characterized by plastic deformation caused by particles indentation, and the other hand the failure mode at the harder materials was grooving. The details and wear mechanism of the coatings produced are described in this investigation. (Author)

  7. Metal-ceramic composite coatings obtained by new thermal spray technologies: Cold Gas Spray (CGS) and its wear resistance; Recubrimientos de materiales compuestos metal-ceramico obtenidos por nuevas tecnologias de proyeccion termica: Proyeccion fria (CGS) y su resistencia al desgaste

    Energy Technology Data Exchange (ETDEWEB)

    Miguel, J. M.; Vizcaino, S.; Dosta, S.; Cinca, N.; Lorenzana, C.; Guilemany, J. M.

    2011-07-01

    In this paper, composite coatings composed by an aluminum bronze metal matrix and a hard ceramic alumina phase obtained by cold spray technique were obtained in order to increase the tribological properties of the pure bronze coatings. The different processes that occur during the coating formation (hardening of the metal particles, fragmentation of the ceramic particles, shot peening on the metal substrate, etc) are described and their effects on the coating properties are studied. Wear tests consisting on Ball-on-Disk tests, abrasion Rubber Wheel tests and erosion tests as well as microhardness and adhesion tests are carried out and the results are correlated with the ceramic phase content of the coatings. It can be concluded that the hard ceramic phase increases the tribological properties with relation of the initial bronze coating. Finally, main wear mechanisms during the tribological tests are described. (Author) 21 refs.

  8. BERKELEY: ALS ring

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1993-06-15

    Everybody at Lawrence Berkeley Laboratory's Center for Beam Physics is pleased with the rapid progress in commissioning LBL's Advanced Light Source (ALS) electron storage ring, the foundation for this third-generation synchrotron radiation facility. Designed for a maximum current of 400 mA, the ALS storage ring reached 407 mA just 24 days after storing the first beam on 16 March. ALS construction as a US Department of Energy (DOE) national user facility to provide high-brightness vacuum ultra-violet and soft x-ray radiation began in October 1987. One technical requirement marking project completion was to accumulate a 50-mA current in the storage ring. The ALS passed this milestone on 24 March, a week ahead of the official deadline. Once injected, the electron beam decays quasi-exponentially primarily because of interactions with residual gas molecules in the storage-ring vacuum chamber. Eventually, when the pressure in the vacuum chamber with beam decreases toward the expected operating level of 1 nano Torr, it will only be necessary to refill the storage ring at intervals of four to eight hours. At present the vacuum is improving rapidly as surfaces are irradiated (scrubbed) by the synchrotron radiation itself. At 100 mA, beam lifetime was about one hour (9 April)

  9. Alimba et al (5)

    African Journals Online (AJOL)

    USER

    There was significant (p<0.05) increase in erythrocytes, haemoglobin ... for its anti-hemorrhoid and anti-inflammatory properties (Afolabi et al., 2008), ... genome instability which may lead to genetic related diseases ... membrane, behavioral pattern, morbidity and mortality. ..... extracts of Phyllanthus amarus in mice and rats.

  10. Taiwo et al (8)

    African Journals Online (AJOL)

    DELL

    Ife Journal of Science. (2016) vol. 18, no. 4. SPATIAL ... Ogun State. On the contrary, published work in some parts of Nigeria had ..... Prevalence among. Age Group (%). Cause of Infection. (%). Adeoye et al.,. 2007. Lagos. Kato-Katz. A. lumbricoides =29.7. Hookworm = 0.7. T. Trichiura = 18.4. S. stercoralis =0.3. Total =49.1.

  11. Rossie et al

    African Journals Online (AJOL)

    PUBLICATIONS1

    ing onto the torso for bike riders (Blocken et al., 2013) or it might ... designing new vehicles as well as for drawing up specific training ... These models were chosen because they repre- ..... muscles is relevant since the bio-mechanical workload ...

  12. aboagye et al.2

    African Journals Online (AJOL)

    PUBLICATIONS1

    14 Aboagye et al. wide variety of birds, including chickens, by piercing the quills of feathers and gnawing the epidermis. In doing so, they can spread disease and lower .... evolution. Oikos, 97: 223-228. Nordenfors, H. and Chirico, J. (2001). Evalua- tion of a sampling trap for Dermanyssus gal- linae (Acari: Dermanyssidae).

  13. Fadimu et al

    African Journals Online (AJOL)

    coconut water has the potential to increase growth and nutritional value of S. mombin(Linn.) so that S. mombin ... of plant growth and development, including seed maturation and ... et al., 2000). Auxins are primary regulators of plant form while ...

  14. Bello et al (9)

    African Journals Online (AJOL)

    Timade VENTURE

    family Solanaceae and it is one of the largest and ... al.,2004). The taxonomy of this important genus is of ... importance of numerical taxonomic method in ..... SME. SAE. SAM. SNI. SER. SWR. SMA. SGI. -6.4. -4.8. -3.2. -1.6. 0. 1.6. 3.2. 4.8.

  15. Iraq and Al Qaeda

    National Research Council Canada - National Science Library

    Katzman, Kenneth

    2008-01-01

    .... The Administration assertions were derived from U.S. intelligence showing a pattern of contacts with Al Qaeda when its key founder, Osama bin Laden, was based in Sudan in the early to mid-1990s and continuing after he relocated to Afghanistan in 1996...

  16. Iraq and Al Qaeda

    National Research Council Canada - National Science Library

    Katzman, Kenneth

    2007-01-01

    .... The Administration's assertions were derived from U.S. intelligence showing a pattern of contacts with Al Qaeda when its founder, Osama bin Laden, was based in Sudan in the early to mid-1990s and continuing after he relocated to Afghanistan in 1996...

  17. Ojo et al (2)

    African Journals Online (AJOL)

    DELL

    network geometry hence control how the samples' ... generate different permeability curves from wire- ... occupy in the reservoir pore system (McPhee et. ..... Fig.3. Poroperm cross-plot for a homogenous reservoir. Ojo et al.: Rock Type Based ...

  18. Agwu et al (6)

    African Journals Online (AJOL)

    DELL

    Enterobacteriaceae, the bacteria Escherichia coli is regarded as non-halophilic, and cannot tolerate high salt concentrations (Abdulkarim et al., 2009). Nevertheless, some strains of E. coli are halo- tolerant and survive in high salt concentrations. The ability to demonstrate such high osmotic pressure is possibly due to the ...

  19. Dichtung als Erfahrungsmetaphysik

    DEFF Research Database (Denmark)

    Magnusson, Gisli

    Rilkeforskning. Fordi Rilke ikke – uden at gøre vold mod hans værk – kan fortolkes ud fra et traditionelt religiøst verdensbillede, har man fortolket ham som en antimetafysisk mo­dernist. Afhandlingen Dichtung als Erfahrungsmetaphysik. Esoterische und okkultistische Modernität bei R. M. Rilke argumenterer for...

  20. Nucleosynthesis of 26Al

    International Nuclear Information System (INIS)

    Casse, M.

    1986-07-01

    A burst of interest has followed the discovery in the galactic plane of the 1.8 MeV gamma line attached to the decay of 26 Al. We discuss the relative merits of supernovae, novae, massive and supermassive mass-losing stars as potential sources of this expressive isotope

  1. Njukeng et al. + DOI

    African Journals Online (AJOL)

    confo

    3 Institute of Agricultural Research and Development (IRAD), Bambui, North West Province, Cameroon. ... Potato (Solanum tuberosum L.) is an important cash-food crop, which is widely ... production in Africa nearly tripled over the past 35 years ... Njukeng et al, Prevalence of Viruses in Potato Seed Tubers in the North West ...

  2. Comentarios al Salto Social

    Directory of Open Access Journals (Sweden)

    Facultad de Ciencias Económicas

    1995-06-01

    Full Text Available 1. El Plan considera que la política social es un componente central de la estrategia macroeconómica. A diferencia de la administración Gaviria, lo social ha dejado de ser un asunto marginal, es consustancial al desarrollo y, por tanto, se le confiere una dimensión cualitativamente diferente.

  3. Hamid et al (24)

    African Journals Online (AJOL)

    USER

    acne, and eye problems (Diaz-Bolio, 1975). Cnidoscolus aconitifolius roots and leaves have been taken as a laxative, diuretic, circulation stimulant, to increase digestion, stimulant for lactation, and to harden the fingernails (Rowe, 1994; Kuti, and. Torres, 1996). Oyagbemi et al., (2011) reported the proximate analysis and ...

  4. Esuuman et al (17)

    African Journals Online (AJOL)

    big timmy

    ether (Sathe et al., 2002). Various extraction conditions such as pH, solvent types (NaOH, NaCl or Ethanol), solvent concentration, extraction time, solvent/flour ratio, may affect the final properties of the extracted protein. When many factors and interactions affect desired responses in a certain process design, Response.

  5. BERKELEY: ALS ring

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Everybody at Lawrence Berkeley Laboratory's Center for Beam Physics is pleased with the rapid progress in commissioning LBL's Advanced Light Source (ALS) electron storage ring, the foundation for this third-generation synchrotron radiation facility. Designed for a maximum current of 400 mA, the ALS storage ring reached 407 mA just 24 days after storing the first beam on 16 March. ALS construction as a US Department of Energy (DOE) national user facility to provide high-brightness vacuum ultra-violet and soft x-ray radiation began in October 1987. One technical requirement marking project completion was to accumulate a 50-mA current in the storage ring. The ALS passed this milestone on 24 March, a week ahead of the official deadline. Once injected, the electron beam decays quasi-exponentially primarily because of interactions with residual gas molecules in the storage-ring vacuum chamber. Eventually, when the pressure in the vacuum chamber with beam decreases toward the expected operating level of 1 nano Torr, it will only be necessary to refill the storage ring at intervals of four to eight hours. At present the vacuum is improving rapidly as surfaces are irradiated (scrubbed) by the synchrotron radiation itself. At 100 mA, beam lifetime was about one hour (9 April)

  6. 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.

  7. La interacción de materiales del sistema sílice-alúmina con productos fluorados aluminosos

    Directory of Open Access Journals (Sweden)

    Verdeja, L. F.

    1998-05-01

    Full Text Available The aim of this paper is to get a first approximation of the systematic study of the corrosion mechanisms of the silica-alumina, alumina and rich-alumina refractory by fluoride compounds and molten aluminum. The thermodynamic results support the main role of the chemical attack and the erosive mechanisms in the wear of the silica-alumina materials. The influence of the composition of the crystalline phases in the degree of the ceramic lining attack is also studied. The results suggest not to use either oxide or nitride high-value materials for the lining of furnaces and transport recipients containing molten aluminum, because of the chemical corrosion by compounds such as cryolite or aluminum fluoride and also, because of the avidity of aluminum towards oxygen. The study of corundum-based materials like the best refractory used in order to react with fluoride compounds and molten aluminum is an alternative to be considered. The study of the crusts adhesion like a protection mechanism of the refractory lining is also a possible approach.

    Este trabajo pretende contribuir al estudio sistemático de los mecanismos de corrosión que experimentan los refractarios sílico-aluminosos, aluminosos y de alta alúmina con productos fluorados y aluminio en estado líquido. Se aportan datos termodinámicos que confirman el papel preponderante del ataque químico y de los mecanismos erosivos en el desgaste de materiales del sistema sílice-alúmina. Se discute, asimismo, la influencia de la composición de las fases cristalinas encontradas en el grado de agresión a los revestimientos cerámicos. Se propone, ante la agresividad de agentes químicamente activos, como la criolita o el fluoruro de aluminio, y la gran afinidad del aluminio por el oxígeno, no aconsejar la utilización de materiales oxídicos y nitrurados de alto valor para el revestimiento de hornos y bolsas de transporte de aluminio. Se propone, como línea de trabajo a seguir, la

  8. Factores asociados al bajo peso al nacer

    Directory of Open Access Journals (Sweden)

    Georgina J Peraza Roque

    2001-10-01

    Full Text Available El bajo peso al nacer (BPN ha constituido un enigma en la ciencia a través de los tiempos. Múltiples son las investigaciones realizadas acerca de las causas que lo producen y las consecuencias que provoca. Su importancia no solo radica en lo que significa en la morbilidad y la mortalidad infantil, sino que estos niños tienen habitualmente múltiples problemas posteriores. El Programa para la Reducción del BPN señala que los niños nacidos con un peso inferior a los 2 500 g presentan riesgo de mortalidad 14 veces mayor durante el primer año de vida, en comparación con los niños que nacen con un peso normal a término. Dentro de los factores de riesgo del BPN se han encontrado con mayor frecuencia en estudios realizados por diferentes autores, los siguientes: el embarazo en la adolescencia, la desnutrición en la madre, el hábito de fumar, la hipertensión arterial durante el embarazo, la sepsis cervicovaginal, la anemia y los embarazos gemelares, entre otros. Es innegable la influencia que el BPN tiene sobre las futuras generaciones, por lo que debe constituir la diana de los esfuerzos que el médico y la enfermera deben desarrollar en su prevención, sobre todo en la comunidadLow birth weight has been an enigma for Science through times. A lot of research works have been carried out about its causes and consequences. The importance of LBW not only lies in its meaning for infant mortality and morbidity but also in the many problems that low birth weight children regularly face in the future. The program for the reduction of LBW points out that newborns weighing under 2500g have during his/her first year of life a mortality risk 14 times higher than newborns with a normal weight at term. Among the low birth weight risk factors, a number of studies by various authors have frequently found the following; pregnancy at adolescence; undernourishment in mothers, smoking, blood hypertension during pregnancy, cervix-vaginal sepsis; anemia, twin

  9. De GPS al mapa

    Directory of Open Access Journals (Sweden)

    Esteban Dörries

    2016-03-01

    Full Text Available Las coordenadas Lambert obtenidas a partir de mediciones con equipos GPS de mano, llamados a veces navegadores, en ciertos casos confunden al usuario, por diferir claramente de su posición real al ser graficadas en un mapa del Instituto Geográfico Nacional (IGN: Esto puede resolverse con suficiente exactitud mediante una transformación de Molodensky, seguida de la correspondiente proyección cartográfica. Sin embargo, los tres parámetros necesarios para la transformación, supuestamente válidos para Costa Rica, se encuentran en muchas variantes y producen obviamente resultados diferentes. En este trabajo se analizan los fundamentos del problema y sus posibles soluciones, culminando con un estudio comparativo de ocho casos, que permite seleccionar los valores más adecuados para los parámetros.

  10. ALS insertion devices

    International Nuclear Information System (INIS)

    Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W.V.; Humphries, D.; Kincaid, B.; Lancaster, H.; Plate, D.

    1990-11-01

    The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system. 18 refs., 9 figs., 5 tabs

  11. Adekola et al (7)

    African Journals Online (AJOL)

    Timothy Ademakinwa

    the South Atlantic between Latitudes 31° and 33.5 ... South Atlantic Ocean in the Early Cretaceous, around 136 Ma (Brown et al., 1996; Reeves and de. Wit, 2000 ..... 3244. 3246.70. L o w e r C re ta c e o u s. P e rio d. /E p o c h. 3244. 3246.70. B a ..... moderate counts of forest species such as ... The other, near shore is rich.

  12. Flipped Classroom al laboratori

    OpenAIRE

    Molés Bort, Jaume

    2014-01-01

    L'article presenta una experiència d'aprenentatge de la geologia mitjançant el treball en grups d'experts. Els alumnes han d'indagar i promoure el seu propi aprenentatge per a assolir un repte que se'ls proposa, i consensuar els criteris per els que avaluaran els seus propis resultats mitjançant rúbriques. L'activitat inclou aspectes artístics, TIC i matemàtics, i segueix un esquema similar al de les WebQuest. Els resultats de l'activitat es presenten juntament amb una enquesta realitzada ent...

  13. Teatro al aire libre

    Directory of Open Access Journals (Sweden)

    Philippe Canac

    2016-11-01

    Full Text Available Siendo cada vez más frecuentes y numerosas las peregrinaciones a la basílica de Notre Dame, de Laus (Altos Alpes, su capacidad resultaba hace tiempo insuficiente para acoger a sus peregrinos. Este fue el motivo de crear, en un terreno situado ante el atrio de la basílica, un conjunto, que permitiese celebrar misas al aire libre, ceremonias litúrgicas o representaciones de teatro religioso y que dispusiese de todas las posibilidades para conseguir la libertad del juego escénico.

  14. Architektur als Vermittlung

    OpenAIRE

    Ott, Konrad

    2016-01-01

    Mit Anbruch der Moderne hat sich die Architektur bewußt von den Stilen vorangegangener Epochen losgesagt und sich fortan als Ausdruck einer neuen Kultur, eines neuen Zeitgeistes legitimiert. Der Philosoph Konrad Ott setzt sich mit dem Spannungsfeld zwischen den humanistischen und ästhetischen Ansprüchen der modernen Architektur, wie sie etwa von LeCorbusier formuliert worden sind, und der Realität, die sich etwa in der "Behältnis-Architektur" der Großstädte zeigt, auseinander. Die kritische T...

  15. Salvar al planeta

    OpenAIRE

    Thomas Sancton

    2015-01-01

    El desastre de Exxon Valdez en Canadá (1989)en que derramaron 262 mil barriles de petróleo en las aguas de Alaska cambió la conciencia de los norteamericanos para bien. Comienzan a preocuparse, les gusta ser ecologistas. Se espera que no sea moda o novelería y que asuman el liderazgo para salvar al planeta, pues la deforestación, el incremento de la población, la quema de combustibles fósiles, el calentamiento global, el agujero de ozono sobre la Antártida dejan intuir que la Tierra está en g...

  16. Programa Padres al Colegio

    OpenAIRE

    Viñeglas Fernández, Sandra

    2014-01-01

    El presente trabajo, es un proyecto orientado a la promoción de la salud, en referencia al virus del papiloma humano (VPH), ya que este virus es el causante de una de las infecciones de transmisión sexual más frecuentes en el mundo, el objetivo de este trabajo, es diseñar una serie de intervenciones que contribuyan a sensibilizar e informar a la ciudadanía, para lograr mejorar la prevención del virus del papiloma humano y el cáncer de cérvix. Como ya es sabido, cualquier intervención sobre...

  17. Del Pasadismo al Futurismo

    OpenAIRE

    Agudo-Martínez, M. J.

    2003-01-01

    Uno de los habituales prejuicios a la hora de abordar el análisis del movimiento futurista, al igual que sucede con el constructivismo, es la consideración del contexto político en el que se desarrollaron ambas vanguardias. Sin embargo, y dejando a un lado un enfoque del arte con finalidad política de signo diverso, habría que insistir en el hecho de que posiblemente sean tanto el futurismo italiano como el constructivismo ruso, los movimientos que con mayor entusiasmo se manifestaron, en un ...

  18. 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.

  19. Appiah-Adjei et al

    African Journals Online (AJOL)

    PUBLICATIONS1

    ing, sale of automobile spare parts, and metal fabrication. Some of these activities generate huge ... Keywords: Groundwater quality, pollution, waste disposal, Suame, Ghana ... of fertilizers (Chen et al., 2007; Parris, 2011;. Shen et al., 2011), ...

  20. AL-USRCRN Station Information

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Documentation of United States Alabama Regional Climate Reference Network (AL-USRCRN) installations in 2006. Installations documented are for AL-USRCRN pilot project...

  1. Derivados vinculados al seguro.

    Directory of Open Access Journals (Sweden)

    De Paz Cobo, Sonia

    2003-01-01

    Full Text Available El presente trabajo tiene como objetivo la presentación de los derivados financieros como instrumentos de cobertura de los riesgos del seguro, así como de los principales proyectos que se desarrollan a través de los mismos, como por ejemplo los derivados sobre el clima. Hay que tener presente las pérdidas multimillonarias ocasionadas en casos como el de la banca Baring’s, o el de Orange County, por citar algunas, que si bien ciertos autores afirman que están en relación directa con el uso de estos productos, no podemos olvidar que los instrumentos derivados se desarrollaron con el objetivo principal de proteger al usuario de la posible volatilidad del activo subyacente. Ya en la industria aseguradora los derivados vinculados a tal actividad son instrumentos donde el pago se condiciona a la ocurrencia de su suceso de siniestro, o serie de sucesos múltiples que disparen las pérdidas. Tras el repaso efectuado y la descripción que este tipo de instrumentos puede tener en la gestión del riesgo por parte de la industria aseguradora, concluiremos con la exposición de las relaciones con el reaseguro tradicional así como una breve referencia al futuro de este tipo de instrumentos

  2. Bukti Kebenaran Al-quran

    OpenAIRE

    Aliyah, Sri

    2015-01-01

    Al Quran is the greatest miracles of Muhammad SAW as the direction of humankind in order to reach eternal happiness. Scientific evidences show that Al Quran has the truth massages, although it was released far before the finding of modern sciences. The researches continue to study the truth of Al Quran an it revealed the historical fact.

  3. Evaluación del Deterioro de los Electrodos al Incrementar el Número de Pulsos del Tiempo de Soldadura en Aceros IF y HSLA Galvanizados y la Afectación de las Propiedades Mecánicas en los Puntos de Soldadura

    Directory of Open Access Journals (Sweden)

    Miguel Fernando Delgado-Pamanes

    Full Text Available Resumen: La soldadura de resistencia por puntos, es el método más importante en la industria ensambladora de carrocería autoportante o monocasco debido a su automatización, su rapidez, flexibilidad de soldar piezas con forma compleja, es económico debido a que no requiere metal de aporte, además de la posibilidad de aplicar pulsos de precalentamiento y de postcalentamiento para mejorar la soldabilidad del punto de soldadura, el cual se define como la capacidad de la estructura de proporcionar protección adecuada a los pasajeros contra lesiones en caso de una colisión, principalmente depende de la integridad y rendimiento mecánico del botón de soldadura. Para extender la vida de los vehículos se producen aceros galvanizados. Sin embargo, los recubrimientos de cinc han incrementado la dificultad de soldabilidad, siendo necesarias corrientes mayores en el proceso, pues se presenta una menor resistencia en la interfase de soldadura debido a una mejor conductividad eléctrica. Este trabajo investiga el efecto del galvanizado en la disminución de la vida de los electrodos, por esta razón, se deduce una pérdida en las propiedades mecánicas en los botones de soldadura conforme se aumenta el número de puntos de soldadura. El objetivo principal del presente estudio es correlacionar el desgaste de los electrodos con las propiedades mecánicas de los botones de soldadura. El procedimiento experimental consiste en hacer 1.000 puntos de soldadura; para cada vigésimo quinto punto de soldadura a partir del primero, los cuales se examinaron por estereoscopia, ensayos de dureza, ensayos de desbotonamiento y ensayos de tensión al corte. En el desgaste del electrodo, se evaluó la cara por impresión en papel carbón, microscopia óptica y espectroscopia de rayos-X (EDX.

  4. Salvar al planeta

    Directory of Open Access Journals (Sweden)

    Thomas Sancton

    2015-01-01

    Full Text Available El desastre de Exxon Valdez en Canadá (1989en que derramaron 262 mil barriles de petróleo en las aguas de Alaska cambió la conciencia de los norteamericanos para bien. Comienzan a preocuparse, les gusta ser ecologistas. Se espera que no sea moda o novelería y que asuman el liderazgo para salvar al planeta, pues la deforestación, el incremento de la población, la quema de combustibles fósiles, el calentamiento global, el agujero de ozono sobre la Antártida dejan intuir que la Tierra está en grave peligro. Se recomienda entonces optar por un desarrollo sustentable.

  5. COMENTARIO AL CASO PINOCHET

    Directory of Open Access Journals (Sweden)

    Alberto Contreras Clunes

    2002-01-01

    Full Text Available El fallo en el caso Pinochet tiene distintas formas de ser analizado. De partida, desde un punto de vista político, también constitucional, del derecho penal. Sin embargo, nos abocaremos al estudio desde el punto de vista procesal, en especial a lo referido al Debido Proceso. Para ello se analizará los presupuestos, la solución dada por la Excma. Corte Suprema y las consecuencias del mismo. Además, se criticará la solución dada, desde la óptica de las garantías procesales del imputado, contenidas en el nuevo proceso penal y lo dispuesto en la Constitución y la Convención Americana de Derechos Humanos. Finalmente, se argumentará en favor de una interpretación finalista y armónica de la Constitución y los tratados internacionales de derechos humanos.The verdict of the Pinochet Case has different ways of being analyzed: from the political, the constitutional, and the penal law points of view. However, we will approach this study from the legal point of view, especially to that referred to as the Proper Process. To do this, the budgets, the solution given by the Most Excellent Supreme Court, and its consequences will be analyzed. Furthermore, the given solution will be criticized from the point of view of the legal guarantees of the accused contained in the new penal process and what is contained in the Constitution and in the American Convention of Human Rights. In conclusion, we will argue in favor of a final and harmonious interpretation of the Constitution and the international agreement of human rights.

  6. Carta al Editor

    Directory of Open Access Journals (Sweden)

    Darío Maldonado Romero

    1991-03-01

    Full Text Available

    Bogotá, 01 de Agosto de 1990
    Señores
    Miembros del Consejo Editorial
    Academia Nacional de Medicina
    E.S.D.

    Señores doctores:

    Con toda consideración y respeto me permito agregar algunas anotaciones al escrito del Académico Alberto Cárdenas Escobar, aparecido en el No. 22 de Medicina, para destacar algunos aspectos de la personalidad del doctor Alberto Schweitzer galardonado con el Premio Nobel de la Paz.

    A los 30 años de edad tomó una decisión dramática: Estudiar Medicina para trabajaren el África Ecuatorial. Cuando terminó sus investigaciones sobre enfermedades tropicales y sus prácticas hospitaLarias, partió para el Gabon al pequeño pueblo de Lambarené. La tarea era desconsoladora; La atención médica había que prestarla al aire libre; iba con su esposa, como enfermera y amanuense, y no se encontraba ni un intérprete, ni un ayudante. Cuando le llegaron la medicina y el equipaje hubo que acomodarlos en un viejo gallinero abandonado; el calor era insoportable y le venían enfermos de varias millas a la redonda, a pie o en Canoas.

    Las enfermedades más difundidas eran Malaria, Disentería, estreptococias y la más mortífera, la Tripanosomiasis Gambiense, para la que empezaban a llegar medicinas nuevas eficaces y las medidas preventivas como el suministro de agua potable y enmallado de ventanas impedían muchas contaminaciones.

    Pero la que causaba mayores dificultades y trabajo era la Mycobacteriasis Anestesiante, incurable, de difícil diagnóstico, afectando a varios miembros de la misma familia, de aspecto horripilante, con complicaciones neuríticas muy dolorosas, frecuente ceguera, e invalideces y procesos erisepelatososacrotéricos, que exigían acompañante para el cambio y lavado de vendas y suministro de alimentos.

    A menos de un año de

  7. Idaaratu al Wahdah al Namthiyah li at Tathwiri al Tarbiyah al Islamiyah

    Directory of Open Access Journals (Sweden)

    Ahmad Danusiri

    2016-04-01

    Full Text Available Islam, through the Quran, proclaims that its mission includes the teachings to the whole universe, Everything in the universe is maintained by Islam, and none of the symptoms are ignored. The revelations also include the traditions of the Prophet that are authentic (shahih and good (hasan in quality. Both the Quran and maqbulah hadiths are accepted by Muslims on the basis of faith. When some experts of UIN Walisongo from various disciplines try to understand the sacred words of these two resources, their understanding continues, reaching the paradigm of the unity of science which essentially unites the normative, social, and natural sciences. The effect of this paradigm has brought up an issue for the author. Is there any hadiths or Prophetic traditions that can be used as a grand theory in the management disciplines of Islamic education.To address this issue, the authors conducted a literature research with the title Development of Islamic Education Management Module. Sources of data were focused on nine books of Hadiths : Sahih al-Bukhari, Sahih al-Muslim, Sunan Abu Dawud, Sunan at-Turmudzi, Sunan an-Nasai, Sunan Ibn Majah, Sunan ad-Darimi, Muwatta Malik, and Musnad Imam Ahmad bin Hanbal in the form of digital data Lidwa Reader Software Book 9 Imam Hadith. The findings of the study stated that the meaning of the word Rabb includes: creating, nurturing, maintaining, teaching, educating, and organizing. Thus, in an academic term, the word Rabb implies a manager or leader. Meanwhile, in the concept of comprehensive manager it contains at least 14 nomenclature denotations: planning, responsibility, organization, coordination, system of employee payroll, learning, resources, humanity, principle of making it easier for the manager to the employee, motivated to achieve optimal performance, preventing unproductivity, education participation, institutional costs, monitoring, and evaluation system. Each nomenclature has numerous hadiths that could serve

  8. Malamih al-Ashwat al-'Arabiyyah wa Makharijaha

    Directory of Open Access Journals (Sweden)

    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.

  9. Morton et al. Reply

    Science.gov (United States)

    Morton, Douglas C.; Nagol, Jyoteshwar; Carabajal, Claudia C.; Rosette, Jacqueline; Palace, Michael; Cook, Bruce D.; Vermote, Eric F.; Harding, David J.; North, Peter R. J.

    2016-01-01

    Multiple mechanisms could lead to up-regulation of dry-season photosynthesis in Amazon forests, including canopy phenology and illumination geometry. We specifically tested two mechanisms for phenology-driven changes in Amazon forests during dry-season months, and the combined evidence from passive optical and lidar satellite data was incompatible with large net changes in canopy leaf area or leaf reflectance suggested by previous studies. We therefore hypothesized that seasonal changes in the fraction of sunlit and shaded canopies, one aspect of bidirectional reflectance effects in Moderate Resolution Imaging Spectroradiometer (MODIS) data, could alter light availability for dry-season photosynthesis and the photosynthetic capacity of Amazon forests without large net changes in canopy composition. Subsequent work supports the hypothesis that seasonal changes in illumination geometry and diffuse light regulate light saturation in Amazon forests. These studies clarify the physical mechanisms that govern light availability in Amazon forests from seasonal variability in direct and diffuse illumination. Previously, in the debate over light limitation of Amazon forest productivity, seasonal changes in the distribution of light within complex Amazon forest canopies were confounded with dry-season increases in total incoming photosynthetically active radiation. In the accompanying Comment, Saleska et al. do not fully account for this confounding effect of forest structure on photosynthetic capacity.

  10. Alternativen als Programm

    Directory of Open Access Journals (Sweden)

    Paulina Dobroć

    2018-03-01

    Full Text Available Der vorliegende Artikel soll einen Beitrag zu theoretischen Überlegungen einer Technikfolgenabschätzung (TA der Alternativen leisten. Ausgehend von der Annahme, dass TA seit ihrer Entstehung den Anspruch auf die Entwicklung von (technischen Alternativen erhoben hat, wird hier der Versuch unternommen, die Rolle der TA im Rahmen aktueller Innovationsprozesse zu reflektieren und (neu zu definieren. Dies scheint vor allem im Hinblick auf aktuelle gesellschaftliche Herausforderungen notwendig. Zu diesem Zweck wird eine Grundannahme Lothar Hacks über das Verhältnis von Gesellschaft und Technik herangezogen. Seine Annahme besagt, dass die kontinuierliche Überführung von sozialen Problemen und Leitbildern in enge technische Lösungsansätze in hochindustrialisierten Ländern dominant und Teil der aktuellen gesellschaftlichen Probleme ist. Diese These wird im vorliegenden Artikel im Hinblick auf einen Perspektivenwechsel als Ausgangspunkt eines zukünftigen Forschungsprogramms der TA fruchtbar gemacht. Hierbei bildet das Denken in Alternativen von gesellschaftlichen Zukünften den zentralen Fokus.

  11. Undulators at the ALS

    International Nuclear Information System (INIS)

    Hoyer, E.; Akre, J.; Chin, J.

    1994-07-01

    At Lawrence Berkeley Laboratory's (LBL) Advanced Light Source (ALS), three 4.6 m long undulators have been completed, tested and installed. A fourth is under construction. The completed undulators include two 5.0 cm period length, 89 period devices (U5.0s) which achieve a 0.85 T effective field at a 14 mm minimum gap and a 8.0 cm period length, 55 period device (U8.0) that reaches a 1.2 T effective field at a 14 mm minimum gap. The undulator under construction is a 10.0 cm period length, 43 period device (U10.0) that is designed to achieve 0.98 T at a 23 mm gap. Undulator magnetic gap variation (rms) is within 25 microns over the periodic structure length. Reproducibility of the adjustable magnetic gap has been measured to be within +/- 5 microns. Gap adjusting range is from 14 mm to 210 mm, which can be scanned in one minute. The 5.1 m long vacuum chambers are flat in the vertical direction to within 0.74 mm and straight in the horizontal direction to within 0.08 mm over the 4.6 m magnetic structure sections. Vacuum chamber base pressures after UHV beam conditioning are. in the mid 10 -11 Torr range and storage ring operating pressures with full current are in the low 10 -10 Torr range. Measurements show that the uncorrelated magnetic field errors are 0.23%, and 0.20% for the two U5.Os and the U8.0 respectively and that the field integrals are small over the 1 cm by 6 cm beam aperture. Device description, fabrication, and measurements are presented

  12. Propiedades mecánicas y tribológicas del material antifricción Al-Ni-grafito obtenido mediante extrusión en caliente

    Directory of Open Access Journals (Sweden)

    Cambronero, L. E. G.

    2004-04-01

    Full Text Available Manufacturing and characterization of bearing materials is the object of the present work. Thus, graphite particles are added to an aluminium matrix as lubricant. It was added as nickel coated graphite in order to avoid a strength decreasing. Mixing of powders following by cold compaction and hot extrusion was the manufacturing way. Extruded materials showed good graphite distribution into the aluminium matrix, with densities between 3.11 to 3.75 g/cm3 as a function of the nickel/graphite content. Hardness and radial crushing strength decrease when graphite content is increased. On the contrary, friction properties are improved with the graphite content because it decreases friction coefficient and wear. Diffusion heat treatment on extruded materials improves furthermore these friction properties but it decreases the radial crushing strength.

    El objeto de este trabajo es la obtención y caracterización de materiales compuestos (MMC´s para la fabricación de cojinetes para fricción en seco. Así se incorpora a una matriz de aluminio, partículas de grafito para actuar como lubricante si bien en forma de grafito recubierto de níquel para disminuir la perdida de resistencia que presentan estos materiales. La fabricación de estos materiales se realizó mediante compactación de las mezclas de polvos en matriz y su extrusión en caliente. Los materiales obtenidos presentaron una buena distribución del grafito en la matriz de aluminio, con densidades entre 3.11 g/cm3 y 3.75 g/cm3 según el contenido de níquel/grafito. La dureza y la resistencia al aplastamiento radial disminuyen al aumentar el contenido en grafito. No obstante, un mayor contenido en grafito si mejora las propiedades a fricción del material, disminuyendo el desgaste ocasionado y reduciendo el coeficiente de fricción. El tratamiento térmico de difusión de los materiales extruidos mejora sus propiedades de fricción si bien disminuye su resistencia al aplastamiento

  13. 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)

  14. Deformation mechanisms of nanotwinned Al

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xinghang [Texas A & M Univ., College Station, TX (United States)

    2016-11-10

    The objective of this project is to investigate the role of different types of layer interfaces on the formation of high density stacking fault (SF) in Al in Al/fcc multilayers, and understand the corresponding deformation mechanisms of the films. Stacking faults or twins can be intentionally introduced (via growth) into certain fcc metals with low stacking fault energy (such as Cu, Ag and 330 stainless steels) to achieve high strength, high ductility, superior thermal stability and good electrical conductivity. However it is still a major challenge to synthesize these types of defects into metals with high stacking fault energy, such as Al. Although deformation twins have been observed in some nanocrystalline Al powders by low temperature, high strain rate cryomilling or in Al at the edge of crack tip or indentation (with the assistance of high stress intensity factor), these deformation techniques typically introduce twins sporadically and the control of deformation twin density in Al is still not feasible. This project is designed to test the following hypotheses: (1) Certain type of layer interfaces may assist the formation of SF in Al, (2) Al with high density SF may have deformation mechanisms drastically different from those of coarse-grained Al and nanotwinned Cu. To test these hypotheses, we have performed the following tasks: (i) Investigate the influence of layer interfaces, stresses and deposition parameters on the formation and density of SF in Al. (ii) Understand the role of SF on the deformation behavior of Al. In situ nanoindentation experiments will be performed to probe deformation mechanisms in Al. The major findings related to the formation mechanism of twins and mechanical behavior of nanotwinned metals include the followings: 1) Our studies show that nanotwins can be introduced into metals with high stacking fault energy, in drastic contrast to the general anticipation. 2) We show two strategies that can effectively introduce growth twins in

  15. Deformation mechanisms of nanotwinned Al

    International Nuclear Information System (INIS)

    Zhang, Xinghang

    2016-01-01

    The objective of this project is to investigate the role of different types of layer interfaces on the formation of high density stacking fault (SF) in Al in Al/fcc multilayers, and understand the corresponding deformation mechanisms of the films. Stacking faults or twins can be intentionally introduced (via growth) into certain fcc metals with low stacking fault energy (such as Cu, Ag and 330 stainless steels) to achieve high strength, high ductility, superior thermal stability and good electrical conductivity. However it is still a major challenge to synthesize these types of defects into metals with high stacking fault energy, such as Al. Although deformation twins have been observed in some nanocrystalline Al powders by low temperature, high strain rate cryomilling or in Al at the edge of crack tip or indentation (with the assistance of high stress intensity factor), these deformation techniques typically introduce twins sporadically and the control of deformation twin density in Al is still not feasible. This project is designed to test the following hypotheses: (1) Certain type of layer interfaces may assist the formation of SF in Al, (2) Al with high density SF may have deformation mechanisms drastically different from those of coarse-grained Al and nanotwinned Cu. To test these hypotheses, we have performed the following tasks: (i) Investigate the influence of layer interfaces, stresses and deposition parameters on the formation and density of SF in Al. (ii) Understand the role of SF on the deformation behavior of Al. In situ nanoindentation experiments will be performed to probe deformation mechanisms in Al. The major findings related to the formation mechanism of twins and mechanical behavior of nanotwinned metals include the followings: 1) Our studies show that nanotwins can be introduced into metals with high stacking fault energy, in drastic contrast to the general anticipation. 2) We show two strategies that can effectively introduce growth twins in

  16. Caracterización mecánica y tribológica de recubrimientos diamond-like carbon aplicados por la técnica deposición química de vapor sobre baldosas cerámicas

    Directory of Open Access Journals (Sweden)

    Jessica Gilabert

    2015-09-01

    Tras la obtención de resultados y su posterior evaluación, se observó una mejora en las propiedades del material cerámico con la aplicación del recubrimiento DLC, tales como la resistencia al desgaste y al rayado, así como su microdureza. No se observaron modificaciones importantes en la rugosidad, con respecto al sustrato original. La mejora de propiedades es limitada cuando las condiciones de desgaste son muy severas.

  17. SANANDO AL SANADOR

    Directory of Open Access Journals (Sweden)

    Juan Pablo Acuña, Dr.

    2017-09-01

    Full Text Available RESUMEN: La dependencia o adicción a sustancias de uso profesional es un problema que puede afectar gravemente a médicos de diferentes especialidades. En la anestesiología hay mayor riesgo de dependencia a opioides e hipnóticos que en otras especialidades y puede llegar a afectar al 1% de los médicos anestesiólogos.La fisiopatología del trastorno por uso de sustancias tiene hechos comunes para diferentes drogas. Interactúan la vulnerabilidad genética y factores psicosociales como predisponentes y los efectos psicobiológicos de la sustancia como factor gatillante. En el caso de los anestesiólogos, la sustancia se encuentra en el lugar de trabajo y por lo tanto, el individuo está constantemente expuesto.Una disfunción previa del sistema de recompensa en el circuito mesocorticolímbico o causada por la exposición a la sustancia adictiva es la piedra central de la neurobiología de las adicciones. Los opioides, anfetaminas, canabinoides, alcohol y nicotina, son algunas de las sustancias exógenas que activan el circuito y causan inicialmente un efecto hedónico que reforzará la conducta por repetir la experiencia. Con el tiempo la interacción con la droga será para evitar los síntomas de abstinencia.Dada la exposición laboral de los anestesiólogos, es necesario prevenir, detectar y tratar precozmente a quienes están abusando de sustancias durante su ejercicio profesional.Por las características de estos fármacos, aspectos psicológicos especiales de los médicos y el contexto laboral se hace necesario un tratamiento especializado y en anestesiólogos la reinserción laboral debe ser un proceso controlado, gradual y con un seguimiento prolongado. SUMMARY: Prescription drugs dependence seriously impairs doctors from differents fields of medicine. Anesthesiology has greater risk than other specialties to opioids and hypnotics dependence, with prevalence up to 1%.Substances use disorder has common mechanisms of disease regardless

  18. Toxic waste treatment with sliding centrifugal plasma reactor; Tratamiento de residuos toxicos con reactores de plasma centrifugo deslizante (PCD)

    Energy Technology Data Exchange (ETDEWEB)

    Pacheco, J.; Pacheco, M.; Valdivia, R.; Ramos, F.; Duran, M.; Hidalgo, M.; Cruz, A.; Martinez, J. C.; Martinez, R.; De la Cruz, S.; Flores, T.; Vidal, E.; Escobar, S. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Garduno, M.; Garcia, M.; Portillo, J.; Torres, C.; Estrada, N.; Velazquez, S.; Vasquez, C. [Instituto Tecnologico de Toluca, Av. Instituto Tecnologico s/n, Ex-Rancho la Virgen, Metepec 52140, Estado de Mexico (Mexico)

    2008-07-01

    The aim is to develop technology for hazardous waste treatment, including the building and putting into operation of a prototype based on a sliding centrifugal plasma technology to demonstrate its ability to degradation taking in account the existing environmental standards. (Author)

  19. 117 - 122 Omoniyi et al

    African Journals Online (AJOL)

    User

    Bayero Journal of Pure and Applied Sciences, 8(2): 117 – 122. Received: ... FOLLOWING MILD EXPOSURE. Omoniyi ... People who work with materials containing mere traces .... obscured physical effect in the animal model (Omoniyi et al.

  20. 150 - 159_Salisu et al.

    African Journals Online (AJOL)

    User

    of interaction occurring in this natural system (Dube et al.,2000). Many soils ... minerals including gold, copper, zinc etc. The Zamfara ... contain unusually problematic concentration of lead and other ..... Copper (Cu) is an essential micronutrient ...

  1. 142 - 149_Safiyanu et al.,

    African Journals Online (AJOL)

    User

    insecticides producing industries whose daily challenge is minimization of malaria burden across the globe. Larvae of ... emerge and currently represents the major threat to ..... eastern Thailand (Pimsamurna et al., 2009) and resistance to ...

  2. 24 - 28_Suleiman et al.

    African Journals Online (AJOL)

    User

    larval instar. Keywords: Antlion, Construction, Density, Distribution, Hunger, Larvae, Pit. INTRODUCTION ... 1987), moisture (Gotelli 1993; Morrison 1994), and shade (scharfet al. .... Pit building was virtually the same in all three instar, and no ...

  3. Laniyan et al (1).cdr

    African Journals Online (AJOL)

    Timothy Ademakinwa

    Pollution of groundwater has become a major environmental problem. Anthropogenic ... drinking water comes from aquifers (Forster et al.,. 1998). Aquifers ... improvement in public health. ..... Arsenic (As): Chemical properties,. Health and ...

  4. 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)

  5. Al clamor de les vuvuzeles

    Directory of Open Access Journals (Sweden)

    Javier Olivera Betrán

    2010-09-01

    Full Text Available El Mundial de Futbol de Sud-àfrica ha situat l’Àfrica al mapa mundial i ha mostrat al món el triomf de l’estil de futbol d’Espanya basat en la col·lectivitat, l’esperit d’equip, la humilitat, la cohesió interna i el joc bonic. L’organització africana, seriosa i eficaç, ha sabut mobilitzar i il·lusionar la població del país que ha participat en el mundial des de l’orgull de ser africà, amb l’esperit alegre, festiu i també reivindicatiu de la gent de l’Àfrica. Aquest esdeveniment suposa el llançament de la marca “Sud-àfrica” al món amb un avís clar d’optar a l’organització d’uns primers Jocs Olímpics a Àfrica (potser els de 2020. S’obre una finestra d’esperança al segle xxi per al continent perdut de la mà de l’esport espectacle tan universal, massiu, emocional i mercantil que també es juga a la canxa de la política i de l’economia.

  6. 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.

  7. 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

  8. Conjuntivitis alérgica

    Directory of Open Access Journals (Sweden)

    Alejandro Tello Hernández

    2008-07-01

    Full Text Available La conjuntivitis alérgica es una de las causas más comunesde consulta externa en oftalmología y tiene una muy altarelación con las reacciones alérgicas sistémicas. Lafisiopatología de las reacciones de hipersensibilidad noshace entender los cuadros clínicos característicos de estapatología y sus diferentes grados de severidad. Eldiagnostico diferencial es amplio, sin embargo hay clavesdiagnosticas que nos orientan rápidamente al diagnosticocorrecto. El tratamiento se enfoca en las medidasfarmacológicas y no farmacológicas, utilizándolas enconjunto para disminuir la recurrencia del cuadro y prevenirsecuelas visuales.

  9. PENDIDIKAN MENURUT AL-GHAZALI

    Directory of Open Access Journals (Sweden)

    Syamsul Kurniawan

    2016-12-01

    Full Text Available Education reform efforts typically begin with a conceptual perspective before implementation. Thus, developing Islamic education usually begins with a study of a figure and his educational thought. And one of the most influential figures whose thought which has Sufi religious pattern has dominated educational thinking atmosphere over the centuries since his death. The purpose of education according to al-Ghazali was to get closer to Allah. He came with a view that the most noble job is to educate: to become a teacher. Al-Ghazali advised that his students, in the learning process, aim to become scientists who could disseminate their knowledge for the sake of humanity values. Keywords: Al-Ghazali, Thought, Islamic Education.

  10. 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.

  11. 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

  12. estigma tolerable al estigma intolerable

    Directory of Open Access Journals (Sweden)

    Nelson Arteaga Botello

    2006-01-01

    cristalización pasa por dos referentes de interacción y relación social al interior del espacio escolar. El primero está constituido por parámetros de normalidad y anormalidad a partir de la localización de estigmas. El segundo se encuentra, a contrapelo de la tendencia anterior, tratando de diluir los efectos de los estigmas al señalarlos como una práctica de tipificación social intolerable o inaceptable.

  13. De la contingencia al destino

    Directory of Open Access Journals (Sweden)

    Heller, Agnes

    1991-10-01

    Full Text Available Not available.

    La modernidad no ha podido dar respuesta al problema de la contingencia histórica, El texto muestra, por medio de metáforas, que el abandono necesario de esta cuestión no significa que estemos abocados al relativismo respecto a la contingencia existencial. La contingencia existencial, individual, sigue presente en la vida de todo individuo. Se sostiene que podemos dar un destino a nuestras vidas, y ésta es la tarea principal del filósofo.

  14. 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.

  15. ¿COLOMBIA DEBE APOSTARLE AL SOFTWARE LIBRE, AL DE FUENTE ABIERTA O AL PROPIETARIO?

    Directory of Open Access Journals (Sweden)

    Luis Alberto Girón Murillo

    2014-06-01

    Full Text Available Es complejo para gestores y administradores conocer las implicaciones que la adopción de modelos de desarrollo de software tendría para una región. Este artículo ofrece una evaluación de las implicaciones dinámicas que para el desarrollo de software de una región tendría el apostar de forma excluyente al software libre, al software de fuente abierta y al software propietario. Se desarrolló un modelo de simulación en Vensim de la dinámica de sistemas en donde se evaluaron 3 escenarios: uno en donde se adopta de forma excluyente el software libre, uno en donde se adopta el software propietario y uno en donde se adopta el software de fuente abierta. Se ofrecen descripciones y explicaciones de los resultados que sugieren las potencialidades de cada uno de los modelos de desarrollo evaluados.

  16. 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.

  17. 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.

  18. 34 - 38 Ashiru et al.

    African Journals Online (AJOL)

    User

    INTRODUCTION. Commercial fish feeds are usually expensive because the traditional or conventional protein source ingredient such as fish meal, soyabean ... consumption (Madu et al., 2003). Fish feed constitute for about 60-80% of management cost in agricultural production (Igonifagha, 1979). Periodic scarcity and.

  19. 39 - 47_Aminu et al.

    African Journals Online (AJOL)

    User

    estimated 453, 000 resulting in the death of a child younger than five years. In Sub-Saharan Africa and. Asia, according to Kotloff et al., (2013), rotavirus is one of the four most common causes of moderate to severe diarrhea among children <5 years of age. Diarrhea is one of the documented '10 killer conditions' among ...

  20. Oyebola et al (23).cdr

    African Journals Online (AJOL)

    Timothy Ademakinwa

    3+ described elsewhere (Oyebola et al., 2010). Ho absorption peaks were obtained from transmission studies carried out with a Cary 5000. UV-VIS-NIR spectrophotometer and corresponding absorption coefficients deduced using the Beer-Lambert law. Spectral emission measurements were carried out using the schematic ...

  1. 180 - 184_ Farouk et al.,

    African Journals Online (AJOL)

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    College of Arts, Science and Remedial Studies, Kano, Nigeria aceutical and Medicinal ... d out to determine the levels of Cadmium (Cd) and Lead (Pb) in m ... and soil. Contamination of als may be due to natural, activities (Wilkinson et ation of ...

  2. Adewale et al (18).cdr

    African Journals Online (AJOL)

    Timothy Ademakinwa

    MATERIAL IN SOIL AND MINE TAILINGS OF AWO AND EDE, OSUN-STATE,. NIGERIA. 1*. 1. 2 ... The materials may be original (such as uranium and thorium) or decay .... following equation (Beck et al., 1972). D = 0.042A (K) + 0.429A.

  3. Idowu et al (19).cdr

    African Journals Online (AJOL)

    Timothy Ademakinwa

    aquifer flow (MacDonald et al., 2005). Typically, it travels vertically downwards through the unsaturated zone to the water table, from where it flows according to the hydraulic gradient, until it reaches an area of discharge where it occurs as springs or seepages, providing part of the dry season flow and constituting part of the.

  4. 94 - 99_Nafiu et al.

    African Journals Online (AJOL)

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    destination for tourist, it promotes tourism and ecotourism in .... Malaysia. It is also similar with the work of Abuessaila et al., (2011) who reported Trichostrongylus spp. (13.5%) ... animals that tend to receives medical attention were reported to ...

  5. Derecho humano al agua y al saneamiento: derechos estrechamente vinculados al derecho a la vida

    OpenAIRE

    Fernández Aller, Maria Celia; Luis Romero, Elena de; Guzmán Acha, Cristina

    2013-01-01

    Los derechos humanos al agua y al saneamiento están íntimamente relacionados con otros derechos esenciales para la vida, como la alimentación o la salud. Su reconocimiento como derechos humanos en 2010 marca un hito importante en el respeto, protección y realización de estos derechos, que se encuentran seriamente vulnerados para una mayoría de población más vulnerable y empobrecida, sobre todo en el ámbito rural. Mucho camino queda aún para conseguir no sólo la disponibilidad de agua y saneam...

  6. Personalidad y tolerancia al dolor

    Directory of Open Access Journals (Sweden)

    JESÚS M.ª CARRILLO

    2005-01-01

    Full Text Available Se examina la relación de algunas variables de personalidad -EPQ-A (Eysenck y Eysenck, 1975, NEO-PI (McCrae y Costa, 1988 y STA -personalidad esquizotípica- y STB -personalidad límite-, de Claridge y Broks (1984, con la tolerancia al dolor experimental inducido mediante agua fría (cold pressor test, según el procedimiento de Staats, Heckmat y Staats (1998 en una muestra filtrada mediante un cuestionario sobre dolor crónico, dolores de cabeza, de espalda, artritis, síndrome de Raynaud, y personas bajo medicación. La tolerancia al dolor experimental se evaluó mediante el Umbral del dolor (tiempo en segundos desde la introducción de la mano en el agua hasta el primer informe de dolor, Mantenimiento del dolor (duración en segundos de la inmersión de la mano desde la aparición del umbral hasta su retirada y Tolerancia al dolor (duración total en segundos de la inmersión de la mano desde su introducción hasta su retirada. Un análisis correlacional, factorial y de regresión por pasos mostraron un efecto cruzado entre medidas de ansiedad (tolerancia negativa al dolor y psicoticismo, siendo psicoticismo junto con control emocional predictores de tolerancia positiva al dolor. En cuanto a psicoticismo, parece que son sus elementos de naturaleza paranoide y de "dureza" los que afectan a una percepción atenuada del dolor.

  7. Large rectification magnetoresistance in nonmagnetic Al/Ge/Al heterojunctions.

    Science.gov (United States)

    Zhang, Kun; Li, Huan-Huan; Grünberg, Peter; Li, Qiang; Ye, Sheng-Tao; Tian, Yu-Feng; Yan, Shi-Shen; Lin, Zhao-Jun; Kang, Shi-Shou; Chen, Yan-Xue; Liu, Guo-Lei; Mei, Liang-Mo

    2015-09-21

    Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can generate a significant direct-current voltage, and this rectification voltage strongly varies with the external magnetic field. We find that the rectification magnetoresistance in Al/Ge Schottky heterojunctions is as large as 250% at room temperature, which is greatly enhanced as compared with the conventional magnetoresistance of 70%. The findings of rectification magnetoresistance open the way to the new nonmagnetic Ge-based spintronics devices of large rectification magnetoresistance at ambient temperature under the alternating-current due to the simultaneous implementation of the rectification and magnetoresistance in the same devices.

  8. Large rectification magnetoresistance in nonmagnetic Al/Ge/Al heterojunctions

    OpenAIRE

    Zhang, Kun; Li, Huan-huan; Grünberg, Peter; Li, Qiang; Ye, Sheng-tao; Tian, Yu-feng; Yan, Shi-shen; Lin, Zhao-jun; Kang, Shi-shou; Chen, Yan-xue; Liu, Guo-lei; Mei, and Liang-mo

    2015-01-01

    Magnetoresistance and rectification are two fundamental physical properties of heterojunctions and respectively have wide applications in spintronics devices. Being different from the well known various magnetoresistance effects, here we report a brand new large magnetoresistance that can be regarded as rectification magnetoresistance: the application of a pure small sinusoidal alternating-current to the nonmagnetic Al/Ge Schottky heterojunctions can generate a significant direct-current volt...

  9. Jongerenwerk als werkplaats voor professionalisering

    Directory of Open Access Journals (Sweden)

    Judith Metz

    2012-03-01

    met wetenschappelijke experimentele kennis als norm, is dat zij niet altijd goed aansluiten bij de complexiteit en flexibiliteit van de uitvoeringspraktijk. Vraag is: wat dan wel? In Amsterdam richten opleidingen en werkveld in 2008 Youth Spot op, het onderzoek- en praktijkcentrum voor jongerenwerk, met als doel om gezamenlijk te werken aan de profilering, professionalisering en praktijkontwikkeling van het jongerenwerk. Dit artikel belicht de aanleiding voor het ontstaan van Youth Spot, de structuur van de samenwerking, de ervaringen met de wijze van samen werken en de meerwaarde voor de professionalisering van het grootstedelijk jongerenwerk. Daarmee biedt dit artikel enerzijds een kijkje in de keuken van het (grootstedelijke jongerenwerk en anderzijds biedt zij inzicht in ervaringen met alternatieve professionalisering strategieën.

  10. Response to Lefebvre et al.

    Science.gov (United States)

    Takeda, K; Kou, I; Kawakami, N; Yasuhiko, Y; Ogura, Y; Imagawa, E; Miyake, N; Matsumoto, N; Sudo, H; Kotani, T; Nakamura, M; Matsumoto, M; Watanabe, K; Ikegawa, S

    2017-11-01

    Congenital scoliosis (CS) is a common vertebral malformation with incidence of up to 1 of 1000 births worldwide. Recently, TBX6 has been reported as the first disease gene for CS: about 10% of CS patients are compound heterozygotes of rare null mutations and a common haplotype composed by 3 SNPs in TBX6. Lefebvre et al in this journal reported that 2 patients with spondylocostal dysostosis (SCD), a rare skeletal dysplasia affecting spine and ribs also have TBX6 mutations: 1 carried the microdeletion and a rare missense variant, and another 2 rare missense variants. We investigated the pathogenicity of the 3 missense variants in SCD by a luciferase assay. The results were negative for the proposal of Lefebvre et al. We consider these 2 SCD patients are more probably compound heterozygotes of null mutations and a common risk haplotype just as CS patients with TBX6 mutations. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. 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.)

  12. Response to Lisovski et al.

    Science.gov (United States)

    Streby, Henry M.; Kramer, Gunnar R.; Peterson, Sean M.; Lehman, Justin A.; Buehler, David A.; Andersen, David

    2018-01-01

    Lisovski et al. [1] describe the widely recognized limitations of light-level geolocator data for identifying short-distance latitudinal movements, recommend that caution be used when interpreting such data, intimated that we did not use such caution and argued that environmental shading likely explained the Golden-winged Warbler (Vermivora chrysoptera) movements described in our 2015 report [2] . Lisovski et al. [1] conclude that the bird movements we reported could not be disentangled from estimation error in stationary animals caused by environmental shading. We argue that, to the contrary, these hypotheses can easily be disentangled because the premise that environmental shading caused synchronous and parallel error among geolocators is false. With their assertion that our location estimates could be biased by >3,500 km on a day with no observable local sources of shading, Lisovski et al. [1] have taken a position of incredulity toward all geolocator-based animal movement data published to date.

  13. Vormundschaftsrecht als Grundlage politischer Herrschaft

    Directory of Open Access Journals (Sweden)

    Arne Duncker

    2006-07-01

    Full Text Available In ihrer beachtlichen und sehr gewissenhaft dokumentierten Arbeit über vormundschaftliche Regentschaften im 16. und 17. Jahrhundert beschreibt Pauline Puppel unter ausführlichem Bezug auf zeitgenössische Literatur und Archivalien sowohl die allgemeine Rechtslage im damaligen Reich als auch die Anwendungsfälle in Hessen, wo zwischen 1500 und 1700 insgesamt viermal eine Landgräfin als Vormünderin des Fürsten zur Regentin ihres Landes wurde. Dies steht exemplarisch für eine bereits in der Frühen Neuzeit mögliche und nicht einmal ganz seltene Form politischer Frauenherrschaft, die bisher oft nicht hinreichend gewürdigt wurde. Puppels Untersuchung ist in zwei Hauptteile gegliedert. Der erste Teil (Das juristische Regelwerk“, S. 34-143 behandelt die zeitgenössischen Rahmenbedingungen der durch Frauen ausgeübten Vormundschaft und Regentschaft. Der zweite Abschnitt („Die Landgräfinnen von Hessen als Regentinnen“, S. 144-307 befasst sich mit der Ausfüllung dieser Regeln durch konkrete Fallbeispiele in Gestalt von Leben und Regentschaft der regierenden Landgräfinnen von Hessen.

  14. Stem cells therapy for ALS.

    Science.gov (United States)

    Mazzini, Letizia; Vescovi, Angelo; Cantello, Roberto; Gelati, Maurizio; Vercelli, Alessandro

    2016-01-01

    Despite knowledge on the molecular basis of amyotrophic lateral sclerosis (ALS) having quickly progressed over the last few years, such discoveries have not yet translated into new therapeutics. With the advancement of stem cell technologies there is hope for stem cell therapeutics as novel treatments for ALS. We discuss in detail the therapeutic potential of different types of stem cells in preclinical and clinical works. Moreover, we address many open questions in clinical translation. SC therapy is a potentially promising new treatment for ALS and the need to better understand how to develop cell-based experimental treatments, and how to implement them in clinical trials, becomes more pressing. Mesenchymal stem cells and neural fetal stem cells have emerged as safe and potentially effective cell types, but there is a need to carry out appropriately designed experimental studies to verify their long-term safety and possibly efficacy. Moreover, the cost-benefit analysis of the results must take into account the quality of life of the patients as a major end point. It is our opinion that a multicenter international clinical program aime d at fine-tuning and coordinating transplantation procedures and protocols is mandatory.

  15. 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

  16. 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

  17. Armaflex in Burj al Arab; Armaflex im Burj al Arab

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, B.

    2003-07-01

    This article describes the Burj al Arab in Dubai, the unique seven-star high-rise hotel. The construction of the hotel, that is built on 250 piles driven into the sand of an artificial island in the Persian Gulf, is described. In particular, various special materials used in the building are described, as are the luxurious fittings and furnishings of the hotel. The cooling and air-conditioning installations that are necessary as a result of the desert climate of Dubai are described and the use of 'Armaflex' elastomer insulating material for the insulation of refrigeration machines and cold-water piping is discussed.

  18. 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 ...

  19. A study of ion damage in Al, Al/Cu and Al/Ag

    International Nuclear Information System (INIS)

    Marikar, P.

    1979-06-01

    Specimens of pure aluminium, aluminium-copper and aluminium-silver have been irradiated with 20 keV helium ions and/or 100 keV aluminium ions and the nature of the damage assessed using transmission electron microscopy. Irradiation with 20 keV helium ions to a dose of 2.7 x 10 15 ions cm -2 results in the formation of interstitial loops and helium gas bubbles. The helium bubbles were detectable only after annealing at a high temperature following irradiation. When the helium preinjected aluminium specimens were irradiated with 100 keV Al + ions to a dose of 84 dpa at temperatures above 150 0 C, voids were observed to form. At a lower dose of 64 dpa, only a high density of dislocation loops was observed. Al-1 wt% Cu alloy containing partially coherent theta' precipitates resists void formation to a considerable extent, and Al-10 wt% Ag alloy containing coherent G.P. zones offers complete resistance to both dislocation loop nucleation and void formation. The experimental results are discussed in the light of the current theories of irradiation induced damage in metals. The importance of the dislocation-sink efficiency for point defects, the gaseous impurity and the alloying elements in determining void formation is highlighted. (author)

  20. Investigations of Al-Dalang and Al-Hawashat meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Gismelseed, A. M., E-mail: abbasher@squ.edu.om [Sultan Qaboos University, College of Science (Oman); Abdallah, S. B. [University of Khartoum, Department of Geology, Faculty of Science (Sudan); Al-Rawas, A. D.; Al-Mabsali, F. N.; Widatallah, H. M.; Elzain, M. E.; Yousif, A. A. [Sultan Qaboos University, College of Science (Oman); Ericsson, T. [Uppsala University, Department of Physics and Material Sciences (Sweden); Annersten, H. [Uppsala University, Department of Earth Sciences (Sweden)

    2016-12-15

    Mössbauer spectroscopy, X-ray diffraction (XRD) measurements, and electron microprobe analysis (EMPA) have been performed on two meteorites named Al-Dalang and Al-Hawashat after identifying their falling sites in the Western region of Sudan. These two meteorites are ordinary chondrites with similar mineralogy. XRD and EMPA show that the two specimens consist of primary olivine, ortho-pyroxene and later crystallising clino-pyroxene as reaction rims against plagioclase. Fe-metal phases are dominated by kamacite (≈6 wt.% Ni) and minor amounts of tetrataenite (≈52 wt.% Ni). Troilite (FeS) and alabandite (MnS) are optically observed as sulphide phases. The Mössbauer measurements at 295 and 78 K are in agreement with the above characterizations, showing at least two paramagnetic doublets which are assigned to olivine and pyroxene and magnetic sextets assigned to kamacite (hyperfine field ≈33.5 T) and troilite FeS (hyperfine field ≈31 T).

  1. FTD and ALS: genetic ties that bind.

    Science.gov (United States)

    Orr, Harry T

    2011-10-20

    Curiously, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), seemingly disparate neurodegenerative disorders, can be inherited together. Two groups (DeJesus-Hernandez et al. and Renton et al.) show that the long sought after ALS/FTD mutation on chromosomal region 9p is a hexanucleotide expansion in C90RF72. These studies, plus a study on X-linked ALS/FTD, provide molecular starting points for identifying pathways that link ALS and FTD pathogenesis. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. 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.

  3. 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

  4. 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

  5. Aportes amazonicos al formativo andino*

    OpenAIRE

    Morales Chocano, Daniel

    2014-01-01

    RESUMEN La tesis de J.C Tello sobre los orígenes amazónicos de la cultura Chavín ha tenido en la iconografía amazónica presente en Chavin sus argumentos mas fuertes, sin embargo, falta mucho por investigar el aspecto ideológico que representan esos iconos como el jaguar, las cabezas trofeo y el uso de alucinógenos, los cuales indudablemente se vinculan al chamanismo amazónico.

  6. Gettysburg: Monumento al mundo libre

    Directory of Open Access Journals (Sweden)

    Neutra, Richard J.

    1961-12-01

    Full Text Available En el verano del año 1958 fui invitado, por las autoridades de la Universidad de Arizona, en Tucson, a la colocación de la primera piedra de su futuro taller, construido para favorecer el desarrollo técnico del Estado. Varios alcaldes y ministros presenciaron la ceremonia, que fue muy interesante, y uno de los periodistas presentes, John Riddick, del "Tucson Daily Citizen", invitó cordialmente, a mi esposa y a mí, a atravesar, al día siguiente, la frontera mejicana, que cruzaba un vasto desierto.

  7. A melancolia em Al Berto

    OpenAIRE

    Camila Emanuele Martins de Souza

    2015-01-01

    Este trabalho objetiva estudar, sob a perspectiva da melancolia, os livros Salsugem (1984) e Horto de Incêndio (1997), de Al Berto. O autor português produz escritos em que a temática da melancolia atravessa a palavra, o que justifica o debruçar-se sobre as construções textuais da poética albertiana, a fim de traçar-lhe novas possibilidades de leitura por esse ângulo. Para isso, com o intuito de compreender o discurso melancólico segue-se o embasamento teórico: de Klibansky, Panosfsky e Saxl ...

  8. 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.

  9. Betaalde arbeid als verdringer van vrijwilligerswerk? Overbelasting als mogelijke verklaring

    Directory of Open Access Journals (Sweden)

    Angela Kok-Van Meer

    2014-06-01

    Full Text Available Do paid work activities displace volunteering? A potential explanation from role overload theoryRecent changes in Dutch society might lead to a shortage of volunteers. On the one hand, the demand for volunteers is increasing: in the social welfare domain because of governmental austerity policies and in other domains such as sports because of the higher supervision intensity of activities. On the other hand, the supply of volunteers is likely to decrease as more and more women and older workers are active in the labor market, which reduces the time that is available for volunteering. Role overload theory would suggest that the increasing labor participation rate of certain categories of workers goes along with a decline of participation in voluntary work. The secondary data analysis shows that various role loads (work, care for children living at home are associated with differences in participation in voluntary work. However, while a higher number of contractual work hours and hours spent on work-related training are negatively associated with volunteer work, care for children living at home is positively associated with volunteering. These results provide only limited support for role overload theory.Betaalde arbeid als verdringer van vrijwilligerswerk? Overbelasting als mogelijke verklaringDe afgelopen jaren hebben zich enkele maatschappelijke veranderingen voorgedaan, die wellicht tot schaarste op de Nederlandse vrijwilligersmarkt zouden kunnen leiden. Enerzijds neemt de vraag naar vrijwilligers toe doordat subsidieregelingen versoberen (bijvoorbeeld in zorg en welzijn en de begeleidingsintensiteit in bepaalde organisaties stijgt (bijvoorbeeld in sport. Anderzijds neemt het aanbod van vrijwilligers af doordat vrouwen en ouderen meer en langer op de arbeidsmarkt actief zijn, waardoor minder tijd beschikbaar is voor vrijwilligerswerk. In dit artikel wordt aan de hand van de role overload theorie nagegaan of het al dan niet deelnemen aan

  10. Muflikhah et al., Afr., J. Infect. Dis.

    African Journals Online (AJOL)

    TOSHIBA

    2017-10-13

    Oct 13, 2017 ... Human infection occurs mainly by ingesting food or water ... Humans can be infected by consumption of uncooked meat, contaminated food or water, ..... Malaysia, Alvarado-Esquivel et al., (2011) in Mexico, Wang et al., (2014) ...

  11. Heterotopia als sociaal-ruimtelijke constructie

    NARCIS (Netherlands)

    Lengkeek, J.

    2003-01-01

    Uitleg van het begrip heterotopia, waar het gaat om het gebruik van de ruimte. Volgens de auteur wordt heterotopia als persoonlijke ruimte en als vrijetijdsruimte op tal van manieren tot stand gebracht; het is een georganiseerde wereld

  12. Benefits for Military Veterans with ALS

    Science.gov (United States)

    ... Chapters Certified Centers and Clinics Support Groups About ALS About Us Our Research In Your Community Advocate ... Veterans Resources for Military Veterans, Families & Survivors The ALS Association is working everyday to support people with ...

  13. con bajo peso al nacer

    Directory of Open Access Journals (Sweden)

    Adriana Mora Antó

    2005-01-01

    Full Text Available Esta investigación dio cuenta de la relación entre el estilo de funcionamiento familiar, los patrones de crianza y las edades de desarrollo evolutivo en niños, nacidos con bajo peso. El estudio descriptivo correlacional se realizó con 41 niños y sus madres, aplicándose cuestionarios sobre funcionamiento familiar, prácticas de crianza y desarrollo infantil. Los resultados señalaron la existencia de un funcionamiento familiar caracterizado por una cohesión amalgamada y una adaptabilidad caótica, una disciplina complaciente, falta de control y de límites claros en la díada madre-hijo. Se trataba de familias monoparentales, donde la temprana edad de concepción, el madresolterismo y el apoyo de la familia extensa eran constantes. Las edades evolutivas registradas indicaron un desarrollo inferior a la edad cronológica, en la mayor parte de los casos; sin embargo, éstas tendieron a ser superiores al compararlas con la edades reales de los infantes. No se encontró una correlación estadísticamente significativa entre la edad de desarrollo y los diferentes factores del funcionamiento familiar para algunos de los rangos de edad considerados; sin embargo, no se lo descartó por completo, especialmente en lo referente al optimismo familiar

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

    Directory of Open Access Journals (Sweden)

    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.

  15. Al-quran dalam Perspektif Budaya

    OpenAIRE

    Sudrajat, Ajat

    2009-01-01

    Al-Quran merupakan kitab suci terakhir yang diturunkan kepada manusia. Tujuan utama diturunkannya al-Quran adalah sebagai kitab petunjuk yang meliputi bidang akidah, syariah, dan akhlak. Akan tetapi di luar ketiga petunjuk tersebut, al-Quran telah memberikan motivasi dan inspirasi kepada umat Islam dalam berbagai bidang kehidupan sehingga melahirkan jenis budaya tertentu. Dialog intelektual yang dilakukan secara kreatif oleh umat Islam terhadap al-Quran ternyata telah menghasilkan lahirnya ge...

  16. 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

  17. Laser alloyed Al-Ni-Fe coatings

    CSIR Research Space (South Africa)

    Pityana, SL

    2008-10-01

    Full Text Available The aim of this work was to produce crack-free thin surface layers consisting of binary (Al-Ni, Al-Fe) and ternary (Al-Ni-Fe) intermetallic phases by means of a high power laser beam. The laser surface alloying was carried out by melting Fe and Ni...

  18. 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

  19. 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

  20. Opportunity's 'Rub al Khali' Panorama

    Science.gov (United States)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Opportunity's 'Rub al Khali' Panorama (QTVR) This panoramic image, dubbed 'Rub al Khali,' was acquired by NASA's Mars Exploration Rover Opportunity on the plains of Meridiani during the period from the rover's 456th to 464th sols on Mars (May 6 to May 14, 2005). Opportunity was about 2 kilometers (1.2 miles) south of 'Endurance Crater' at a place known informally as 'Purgatory Dune.' The rover was stuck in the dune's deep fine sand for more than a month. 'Rub al Khali' (Arabic translation: 'the empty quarter') was chosen as the name for this panorama because it is the name of a similarly barren, desolate part of the Saudi Arabian desert on Earth. The view spans 360 degrees. It consists of images obtained in 97 individual pointings of the panoramic camera. The camera took images with five camera filters at each pointing. This 22,780-by-6,000-pixel mosaic is an approximately true-color rendering generated using the images acquired through filters admitting light wavelengths of 750, 530, and 480 nanometers. Lighting varied during the nine sols it took to acquire this panorama, resulting in some small image seams within the mosaic. These seams have been smoothed in sky parts of the mosaic to better simulate the vista that a person would see if able to view it all at the same time on Mars. Opportunity's tracks leading back to the north (center of the panorama) are a reminder of the rover's long trek from Endurance Crater. The deep ruts dug by Opportunity's wheels as it became stuck in the sand appear in the foreground. The crest and trough of the last ripple the rover crossed before getting stuck is visible in the center. These wind-formed sand features are only about 10 to 15 centimeters (4 to 6 inches) tall. The crest of the actual ripple where the rover got stuck can be seen just to the right of center. The tracks and a few other places on and near ripple crests can be seen in this color image to

  1. Trato verbal paterno al adolescente

    Directory of Open Access Journals (Sweden)

    Rodríguez Juan Carlos

    1995-06-01

    Full Text Available

    En alguna ocasión se ha escuchado una palabra, que causa un sentimiento y a la vez un recuerdo, que lleva a evocar la adolescencia o la infancia, se recuerda quien la pronunciaba y en que ocasión la decía. Este es el poder que tiene una palabra y más aún si es dicha por el padre, puesto que este es la figura significativa que se lleva en la memoria. De aquí nace el interés de realizar un estudio, en donde se describe y analice la percepción y el sentimiento del adolescente, quien en esta etapa es vulnerable al cambio, ya que está buscando su propia identidad; que con el trato verbal paterno la encontrara sin ninguna dificultad o por el contrario nunca la encontrará.

     

  2. Compliance als Schutz vor Verbandsverantwortlichkeit?

    Directory of Open Access Journals (Sweden)

    Alexander Tipold

    2016-05-01

    Full Text Available Compliance bedeutet nicht nur Einhaltung und Beachtung von Vorschriften, sondern betrifft auch Maßnahmen, die die Einhaltung der Rechtsnormen absichern sollen und läuft somit auf eine Übererfüllung von Verpflichtungen hinaus. Wenn es keinen klaren Maßstab für Kontroll- und Überwachungspflichten gibt, besteht die Gefahr, dass Strafverfolgungsbehörden die Compliance-Maßnahmen als Maßstab heranziehen und so eine Verschärfung der Pflichten erzeugen. Nach den Regeln des Verbandsverantwortlichkeitsgesetzes schließt im Übrigen das beste Compliance-System nicht zwingend die Verbandsverantwortlichkeit aus, steht aber unter Umständen einem Verfahren gegen den Verband entgegen.

  3. 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.)

  4. Estar ahí, al cuidado de un paciente con demencia Being there, ever caring for a patient with dementia

    Directory of Open Access Journals (Sweden)

    Margarita María Gómez Gómez

    2007-03-01

    Full Text Available Por causa de las pérdidas orgánicas, la persona con demencia se reduce cada vez más hasta la total invalidez, y si no encuentra quién se ocupe de ella, se degradará hasta la completa indigencia. Objetivo: Comprender las razones que tiene el cuidador de un familiar con demencia para estar ahí, a su lado, y las acciones que realiza para mantenerse en el cuidado. Metodología: El estudio se realizó en Medellín, Colombia, desde enero de 2002 hasta junio de 2004 con los lineamientos propuestos por la Teoría Fundada; se entrevistaron 22 individuos, cuya característica común era llevar mínimo tres años al cuidado de una persona con demencia. Los participantes se contactaron a través del Programa de Cuidadores del Grupo de Neurociencias de la Universidad de Antioquia y del programa Adulto Mayor, del Instituto de Seguros Sociales; el análisis se hizo manualmente. Resultados: "Estar ahí" es una decisión que toman los cuidadores, motivada por la relación filial o familiar con la persona cuidada, y que está sustentada en cuatro asuntos culturales: función socio-económica del grupo, tradición, reciprocidad y religión. Se constataron, además, los sentimientos de desgaste que viven los cuidadores para mantenerse en el cuidado y su necesidad de información, aprender de la experiencia, reflexión, programar otras actividades y apoyo. Conclusión: El cuidador de un paciente con demencia reconoce que "solo no puede", por lo que urge crear ambientes y espacios de apoyo a los cuidadores, para contribuir a su bienestar y salud.Due to their organic losses demented patients evolve towards total invalidity. If they do not find caring people absolute destitution awaits them. Objective: To understand caregiver reasons for "being there" to a patient with dementia and what are his actions to remain giving care. Methodology: This grounded study was carried in Medellín from January 2002 to June 2004. Twenty-two people with a minimum three years

  5. 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.)

  6. 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

  7. TEM characterization of Al-C-Cu-Al2O3 composites produced by mechanical milling

    International Nuclear Information System (INIS)

    Santos-Beltran, A.; Gallegos-Orozco, V.; Estrada-Guel, I.; Bejar-Gomez, L.; Espinosa-Magana, F.; Miki-Yoshida, M.; Martinez-Sanchez, R.

    2007-01-01

    Novel Al-based composites (Al-C-Cu-Al 2 O 3 ) obtained by mechanical milling (MM), were characterized by transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). Analyses of composites were carried out in both, the as-milled and the as-sintered conditions. C nanoparticles were found in the as-milled condition and Al 2 O 3 nanofibers were found in as-sintered products, as determined by EELS. C and Cu react with Al to crystallize in Al 3 C 4 and Al 2 Cu structures, respectively

  8. 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...

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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

  15. Entrevista al narrador Tommaso Pincio

    Directory of Open Access Journals (Sweden)

    Franco Zangrilli

    2016-07-01

    Full Text Available El autor Tommaso Pincio, seudónimo di Marco Colapietro (Roma, 1963, es sin lugar a dudas uno de los narradores de mayor proyección en el panorama literario de los últimos tiempos. Iniciada su carrera en 1999 con M., ha publicado títulos como Lo spazio sfinito (2000 y Un amore dell'altro mondo (2002, en el que narra la vida de Kurt Cobain, líder del grupo Nirvana, a través de la visión de un amigo imaginario. A estas dos novelas siguieron La ragazza che non era lei (2005, Gli alieni (2006 o Cinacittà. Memorie del mio delitto efferato (2008, ambientada en una Roma colonizada por los chinos y abandonada por los mismos romanos a causa de problemas medioambientales. Títulos como L'hotel a zero stelle (2011, un ensayo autobiográfico en el que plantea diálogos ficticios con algunos de los grandes nombres de la literatura o la más reciente Panorama (2015, le han hecho valerse un hueco provilegiado entre los nuevos narradores surgidos en estas primeras décadas de siglo. Justamente la publicación de esta última novela, Panorama, ha servido de excusa al profesor Franco Zangrilli, gran conocedor de su obra, a plantearle algunas preguntas sobre temas clave de su producción.

  16. Comentario al libro: ACADEMIA MUTISIANA

    Directory of Open Access Journals (Sweden)

    Efraím Otero Ruiz

    2012-04-01

    Full Text Available Por tercera vez en un quinquenio ocupo este podio para ocuparme de uno de los libros del grupo de inmunogenética (o de anti-inmunohistoria, diría yo de la Universidad Javeriana, esta vez enriquecido con la presencia del P. Ortiz Valdivieso, orquídeologo y mutisiólogo y del Dr. Uribe Angel notable historiador educativo, y presentado admirablemente por el P. Durán Casas, Vicerrector Académico de la Universidad Javeriana. En el prólogo, citando desde Sarton y Ziman en los 70s. hasta Mauro Torres en el 2011 afirmo que, aunque suene extraño, parece como si las Academias florecieran entre las guerras. Tal sucedió con la de Platón, “la máxima institución de enseñanza superior surgida en el mundo”, -al decir de Sartonenmarcada desde las guerras del Peloponeso, hasta el final de la dominación espartana de Atenas en el siglo IV antes de Cristo. Según dichos autores, las Academias han simbolizado una manera de continuar la vida espiritual entre uno y otro conflicto.

  17. Structural features in Ni-Al alloys

    International Nuclear Information System (INIS)

    Abylkalykova, R.B.; Kveglis, L.I.; Rakhimova, U.A.; Nasokhova, Sh.B.; Tazhibaeva, G.B.

    2007-01-01

    Purpose of the work is study of structural transformations under diverse memory effect in Ni-Al alloys. Examination were conducted in following composition samples: Ni -75 at.% and Al - 25 at.%. The work is devoted to clarification reasons both formation atom-ordered structures in inter-grain boundaries of bulk samples under temperature action and static load. Revealed inter-grain inter-boundary layers in Ni-Al alloy both bulk and surface state have complicated structure

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Superbend era begins swiftly at the ALS

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Art; Tamura, Lori

    2001-11-29

    The successful installation and commissioning of high-field superconducting bend magnets (superbends) in three curved sectors of ALS storage ring was the first time the magnet lattice of an operating synchrotron light source has been retrofitted in this fundamental way. As a result, the ALS now offers an expanded spectral range well into the hard x-ray region without compromising either the number of undulators or their high brightness in the soft x-ray region for which the ALS design was originally optimized. In sum, when the superbend-enhanced ALS started up for user operations in October 2001, it marked the beginning of a new era in its history.

  1. Referral bias in ALS epidemiological studies.

    Science.gov (United States)

    Logroscino, Giancarlo; Marin, Benoit; Piccininni, Marco; Arcuti, Simona; Chiò, Adriano; Hardiman, Orla; Rooney, James; Zoccolella, Stefano; Couratier, Philippe; Preux, Pierre-Marie; Beghi, Ettore

    2018-01-01

    Despite concerns about the representativeness of patients from ALS tertiary centers as compared to the ALS general population, the extent of referral bias in clinical studies remains largely unknown. Using data from EURALS consortium we aimed to assess nature, extent and impact of referral bias. Four European ALS population-based registries located in Ireland, Piedmont, Puglia, Italy, and Limousin, France, covering 50 million person-years, participated. Demographic and clinic characteristics of ALS patients diagnosed in tertiary referral centers were contrasted with the whole ALS populations enrolled in registries in the same geographical areas. Patients referred to ALS centers were younger (with difference ranging from 1.1 years to 2.4 years), less likely to present a bulbar onset, with a higher proportion of familial antecedents and a longer survival (ranging from 11% to 15%) when compared to the entire ALS population in the same geographic area. A trend for referral bias is present in cohorts drawn from ALS referral centers. The magnitude of the possible referral bias in a particular tertiary center can be estimated through a comparison with ALS patients drawn from registry in the same geographic area. Studies based on clinical cohorts should be cautiously interpreted. The presence of a registry in the same area may improve the complete ascertainment in the referral center.

  2. Decoding ALS: From Genes to Mechanism

    Science.gov (United States)

    Taylor, J. Paul; Brown, Robert H.; Cleveland, Don W.

    2017-01-01

    Preface Amyotrophic lateral sclerosis (ALS) is a progressive and uniformly fatal neurodegenerative disease. A plethora of genetic factors underlying ALS have now been identified that drive motor neuron degeneration, increase susceptibility to the disease, or influence the rate of progression. Emerging themes include dysfunction in RNA metabolism and protein homeostasis, with specific defects in nucleocytoplasmic trafficking, induction of endoplasmic reticulum stress, and impaired dynamics of ribonucleoprotein bodies such as RNA granules that assemble through the process of liquid-liquid phase separation. Extraordinary recent progress in understanding the biology of ALS provides new grounds for optimism that meaningful therapies for ALS will be identified. PMID:27830784

  3. Genetics of Familial and Sporadic ALS

    Science.gov (United States)

    2018-03-27

    Amyotrophic Lateral Sclerosis (ALS); Familial Amyotrophic Lateral Sclerosis; Amyotrophic Lateral Sclerosis With Frontotemporal Dementia; Lou Gehrig's Disease; Motor Neuron Disease; Primary Lateral Sclerosis

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Comparación del desgaste por abrasión y el desgaste por deslizamiento de los aceros aisi/sae 1020, 1045 y 4140

    Directory of Open Access Journals (Sweden)

    Gustavo Jiménez-Torrado

    2012-01-01

    Full Text Available Two ways of evaluating the resistance to the wear, these are analyzed from the quantitative and qualitative point of view. Wear tests were realized by graze and wear by slide according to the procedure ASTM G65 and G99, in the steels AISI/SAE 1020, 1045 and 4140. The factors of study are the load, the speed of slide and the slid distance; all the factors were combined to determine the behavior of every wear. The loss of material is compared by the model Archard. The results of the tests show that the behavior of the desgate of the steels they are proportional to the factors of load and slid distance. The spoiled surfaces show typical characteristics of both types of wear, showing a relation with the experimental factors.

  6. 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...

  7. Formation of AlFeSi phase in AlSi12 alloy with Ce addition

    Directory of Open Access Journals (Sweden)

    S. Kores

    2012-04-01

    Full Text Available The influence of cerium addition on the solidification sequence and microstructure constituents of the Al-Si alloys with 12,6 mass % Si was examined. The solidification was analyzed by a simple thermal analysis. The microstructures were examined with conventional light and scanning electron microscopy. Ternary AlSiCe phase was formed in the Al-Si alloys with added cerium during the solidification process. AlSiCe and β-AlFeSi phases solidified together in the region that solidified the last. Cerium addition influenced on the morphology of the α-AlFeSi phase solidification.

  8. Tadris Al Mufradat Li Tathbiq Maharah Al Kalam Fi Madrasah Al Muallimin Al Islamiyyah Li Mahad Bait Al Arqam Balong Jember

    Directory of Open Access Journals (Sweden)

    Muhammad Ardy Zaini

    2017-06-01

    Full Text Available There are four  skills in teaching Arabic. Ie listening, speaking, reading, and writing. Among these four, speaking considered one of the most important objectives of learning foreign language. In order to speak properly, one must know the vocabulary and apply it in a sentence. The aims of this research is to describe the teaching of vocabulary to apply the speaking skill in the school of Islamic teachers in the Institute of Bait al Arqom Balong Jember. This study used qualitative approach. The data collection was taken trough observation, personal interview, history and documentation. The teaching of vocabulary to apply the speaking skill at the Islamic Teachers' School at the Institute of Bait Al Arqam Balong Jember has gone well in terms of planning (general objectives and specific objectives, implementation (materials, use of the teaching method and teaching aids, and evaluation (assessment and evaluation. This teaching is to apply the speaking skill in terms of conversation or dialogue and lecture.

  9. Kritik al-Ghazali terhadap Kekekalan Alam

    Directory of Open Access Journals (Sweden)

    Sahidi Mustafa

    2015-09-01

    Full Text Available The concept of the creation of universe offered by Neo-Platonism philosopher such as al-Kindi, al-Farabi, and Ibnu Sina are philosophical concept existed and came as an early moment of development of Islamic philosophy interrelated to God, ultimately about his Existence and Characteristics. One of the topics is how God created the universe. According to al-Farabi and Ibnu Sina, God created this universe by way of emanation in order to prevent Himself from the new attitudes. Consequently, universe has eternal feature (qadim as God as well, in the case of everything overflowed from qadim is also qadim. Al-Ghazali refuted this theory because it contradicted with al Qur’an’s thought which clearly explained that God created the entire universe. The universe should not qadim and it means that God existed in the first, and then created universe later as we know today. On the contrary, in the view of Muslim philosopher, the universe should be qadim because God created it from all eternity. For them, it is impossible that God existed by Himself without any creation before. God, according to them is impossible to be changed, so that is impossible as well if God changed from did not create yet before and then creates. Al-Ghazali persistently opposed the concept of eternity. Al Ghazali saw if this universe is qadim so it is impossible that universe created by God. The concept of qadim will led to the conclusion that universe born by itself, it was not created by God. This critique has been written by al-Ghazali in Tahafut al-Falasifah. This paper will present the concept of eternity which was discussed by al-Farabi and Ibn Sina and al Ghazali’s critique toward it as well.

  10. ALS and other motor neuron diseases.

    Science.gov (United States)

    Tiryaki, Ezgi; Horak, Holli A

    2014-10-01

    This review describes the most common motor neuron disease, ALS. It discusses the diagnosis and evaluation of ALS and the current understanding of its pathophysiology, including new genetic underpinnings of the disease. This article also covers other motor neuron diseases, reviews how to distinguish them from ALS, and discusses their pathophysiology. In this article, the spectrum of cognitive involvement in ALS, new concepts about protein synthesis pathology in the etiology of ALS, and new genetic associations will be covered. This concept has changed over the past 3 to 4 years with the discovery of new genes and genetic processes that may trigger the disease. As of 2014, two-thirds of familial ALS and 10% of sporadic ALS can be explained by genetics. TAR DNA binding protein 43 kDa (TDP-43), for instance, has been shown to cause frontotemporal dementia as well as some cases of familial ALS, and is associated with frontotemporal dysfunction in ALS. The anterior horn cells control all voluntary movement: motor activity, respiratory, speech, and swallowing functions are dependent upon signals from the anterior horn cells. Diseases that damage the anterior horn cells, therefore, have a profound impact. Symptoms of anterior horn cell loss (weakness, falling, choking) lead patients to seek medical attention. Neurologists are the most likely practitioners to recognize and diagnose damage or loss of anterior horn cells. ALS, the prototypical motor neuron disease, demonstrates the impact of this class of disorders. ALS and other motor neuron diseases can represent diagnostic challenges. Neurologists are often called upon to serve as a "medical home" for these patients: coordinating care, arranging for durable medical equipment, and leading discussions about end-of-life care with patients and caregivers. It is important for neurologists to be able to identify motor neuron diseases and to evaluate and treat patients affected by them.

  11. 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.

  12. Experimental investigation of the Al-Y phase diagram

    International Nuclear Information System (INIS)

    Liu Shuhong; Du Yong; Xu Honghui; He Cuiyun; Schuster, Julius C.

    2006-01-01

    The Al-Y phase diagram has been reinvestigated with 16 key alloys over its whole composition range by means of differential thermal analysis, X-ray diffraction, optical microscopy, and scanning electron microscopy with energy dispersive X-ray techniques. The existence of five intermetallic phases, Al 3 Y, Al 2 Y, AlY, Al 2 Y 3 , and AlY 2 , has been confirmed. Al 2 Y and Al 2 Y 3 melt congruently at 1490 ± 2 and 1105 ± 2 deg. C, respectively. Al 3 Y, AlY, and AlY 2 are formed via the peritectic reactions L + Al 2 Y ↔ Al 3 Y at 980 ± 2 deg. C, L + Al 2 Y ↔ AlY at 1138 ± 2 deg. C, and L + Al 2 Y 3 ↔ AlY 2 at 977 ± 2 deg. C, respectively. Three eutectic reactions L ↔ (Al) + Al 3 Y at 637 ± 2 deg. C, L ↔ AlY + Al 2 Y 3 at 1081 ± 2 deg. C, and L ↔ AlY 2 + (αY) at 955 ± 2 deg. C , are observed. The previously reported Al 3 Y 5 , AlY 3 compounds were not found. A revised Al-Y phase diagram is presented mainly based on the present experimental results

  13. Explosive destruction of "2"6Al

    International Nuclear Information System (INIS)

    Kahl, D.; Yamaguchi, H.; Shimizu, H.

    2016-01-01

    The γ-ray emission associated with the radioactive decay of "2"6Al is one of the key pieces of observational evidence indicating stellar nucleosynthesis is an ongoing process in our Galaxy, and it was the first such radioactivity to be detected. Despite numerous efforts in stellar modeling, observation, nuclear theory, and nuclear experiment over the past four decades, the precise sites and origin of Galactic "2"6Al remain elusive. We explore the present experimental knowledge concerning the destruction of "2"6Al in massive stars. The precise stellar rates of neutron-induced reactions on "2"6Al, such as (n,p) and (n,α), have among the largest impacts on the total "2"6Al yield. Meanwhile, reactions involving the short-lived isomeric state of "2"6Al such as radiative proton capture are highly-uncertain at present. Although we presented on-going experimental work from n TOF at CERN with an "2"6Al target, the present proceeding focuses only on the "2"6Al isomeric radioactive beam production aspect and the first experimental results at CRIB.

  14. Handlung und Kommunikation als Grundbegriffe der Soziologie

    NARCIS (Netherlands)

    Martens, W.P.M.; Albert, H.; Greshoff, R.; Schützeichel, R.

    2010-01-01

    Handlung und Kommunikation gelten in der Soziologie manchmal als alternative, konkurrierende Grundbegriffe für die Beschreibung und Erklärung sozialer Zusammenhänge (siehe u.a. Luhmann 1984; 1990; Schneider 1994; Stichweh 2000; Greshoff 1999; Schwinn 2001; Albert et. al. 2003). Eine Soziologie,

  15. Kus on al-Zarqawi? / Aadu Hiietamm

    Index Scriptorium Estoniae

    Hiietamm, Aadu, 1954-

    2005-01-01

    Suurbritannia nädalalehe Sunday Times andmetel on Iraagi tagaotsituim mässaja, terrorivõrgustiku al Qaeda liitlane Abu-Musab al-Zarqawi pärast USA raketirünnakus haavatasaamist riigist põgenenud

  16. Miércoles al cine

    OpenAIRE

    Aguado Franco, Juan Carlos

    2014-01-01

    Se analiza un caso concreto de demanda ante una iniciativa empresarial: los miércoles al cine. Se analiza un caso concreto de demanda ante una iniciativa empresarial: los miércoles al cine. Fundamentos del Análisis Económico

  17. Oke et al 2 (12).cdr

    African Journals Online (AJOL)

    Timothy Ademakinwa

    The study revealed that PES contained calcium, aluminum, and iron as part of its major components. 2+. 2+ ... carbon (Chan et al., 1994) , chitosan (Schmub et al., .... (1.735 g of nickel chloride) in 200 ml of distilled. ÷. ÷. ר. צ. ח. ח. ט. ז. -. = 1. 2. 1. 100. (%). W. W. W. Mc. ÷. ÷. ר. צ. ח. ח. ט. ז. -. = 2. 3. 2. 100. (%). W. W. W. VS. ÷. ÷.

  18. Abdullah G M Al-Sehemi

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences. Abdullah G M Al-Sehemi. Articles written in Journal of Chemical Sciences. Volume 121 Issue 6 November 2009 pp 983-987. Multifunctional switches based on bis-imidazole derivative · Abdullah M A Asiri Gameel A Baghaffar Khadija O Badahdah Abdullah G M Al-Sehemi ...

  19. Primary (AL) amyloidosis with gastrointestinal involvement

    DEFF Research Database (Denmark)

    Madsen, Lone Galmstrup; Gimsing, Peter; Schiødt, Frank V

    2009-01-01

    OBJECTIVE: Immunoglobulin light-chain (AL) amyloidosis is a rare disease that can affect several organs. The aim of this study was to characterize patients with gastrointestinal manifestations of AL amyloidosis, in terms of symptoms, biochemistry, and outcome. MATERIAL AND METHODS: Retrospectivel...

  20. Kultur als Ordnungshypothese über Raum?

    OpenAIRE

    Klüter, Helmut

    2009-01-01

    Inhalt: 1 Einleitung 2 Zur Attraktivität von Kultur 3 Kulturologische Methodik 4 Schnittmengen mit und Bindearme zur Kulturgeographie 5 Kritische Argumente gegen Kultur als Ordnungshypothese über Raum 6 Räumliche Abstraktion als Ordnungsstrategie über „Kultur“? 7 Zusammenfassung

  1. Al-Biruni: A Muslim Critical Thinker

    Directory of Open Access Journals (Sweden)

    Mohammad Noviani Ardi

    2016-03-01

    Full Text Available As an academic course, critical thinking has emerged in the last century as the one of the important subjects, especially in the second half. But as a kind of thinking and a process of the human reason, it was exist as old as mankind. What are known, nowadays, as (standards of critical thinking or (characteristic of critical thinker were used by some ancient Greek philosophers, e.g. Socrates, Aristotle, as well as great Muslim scholars, e.g. al-Biruni, al-Ghazali, etc. al-Biruni was known as a great Muslim scholar due to objectively scientific method in his works. Moreover, he also was famed in comparative religion which early in history of discipline of comparative religion. However, this study attempts to talk about al-Biruni, one of greatest Muslim scholar in history from another side of previously discussion. It is tries to analyze al-Biruni as a Muslim critical thinker based on his monumental work of Tahqiq ma li al-Hind min Maqulah Maqbulah fi al-‘Aql aw Mardhulah or it is known by Kitab al-Hind.

  2. Studies on SiC(p) reinforced Al-Al sub 3 Ni eutectic matrix composites

    International Nuclear Information System (INIS)

    Masrom, A.K.; Foo, L.C.; Ismail, A.B.

    1996-01-01

    An investigation on processing of Al-5.69wt% Ni eutectic with SiC particulate composites is reported. The intermetallic composites are prepared by elemental powder metallurgy route and sintered at two different temperatures, i.e., 600 degree C and 620 degree C. Results show that the metal matrix was Al-Al sub 3 Ni eutectic. The phase analysis by XRD identified the presence of Al sub 3 Ni and Al as dominant phases together with silicon and Al sub 4 C sub 3 phase as minor phases. The Al sub 4 C sub 3 and Si phases are formed during sintering due to SiC-Al interface reaction. SEM micrographs also reveal the formation of microvoid surrounding the SiC particle

  3. Data supporting Al-Abed et al., Environ. Sci.: Nano, 2016,

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data files representing each of the Figures and Tables published in Al-Abed et al., Environ. Sci.: Nano, 2016, 3, 593. The data file names identify the Figure or...

  4. Konsepsi Ibnu Jarir Al-Tabari Tentang Al-Qur’an, Tafsir Dan Ta’wil

    Directory of Open Access Journals (Sweden)

    A.M Ismatulloh

    2012-12-01

    Full Text Available The objective of this research is to describe the concept of Ibnu Jarir al-Tabari about al-Qur’an, tafsir and ta’wil. Ibn Jarir al-Tabari is an outstanding expert in the classic Islamic tradition. His knowledge in hadits, fiqh, lughah, history, and tafseer is unquestionable. This study uses an analytical descriptive design. The findings show that: Firstly, in defining al-Qur’an, al-Tabari focused on the al-Qur’an as an Arabic language text, not in other language. Secondly, al-Qur’an is written in sab’ah ahruf. It means that there are 7 different kinds of language with the same meaning. Thirdly, al-Qur’an comes from seven heaven’s door. Fourthly, there is no different word between tafseer and ta’wil. They have same meaning. These concepts are different to other concepts proposed by other ulama.

  5. Synthesis and structural transformations of hydrotalcite-like materials Mg-Al and Zn-Al

    NARCIS (Netherlands)

    Prihod'ko, R.V.; Sychev, M.V.; Astrelin, I.M.; Erdmann, K.; Mangel, A.; Santen, van R.A.

    2001-01-01

    Mg-Al and Zn-Al hydrotalcite-like layered double hydroxides of various compositions were synthesized and characterized. A detailed comparative analysis of the structure and composition of starting and reconstructed layered double hydroxides was made

  6. Tailoring ultrafine grained and dispersion-strengthened Ti2AlC/TiAl ...

    Indian Academy of Sciences (India)

    and Ti-Al pre-alloyed powders at low temperature of 1150◦C. The composite mainly consisted ... Metal–matrix composites; mechanical properties; microstructures; sintering. 1. Introduction γ-TiAl-based intermetallic alloys have been extensively.

  7. Electric quadrupole moments of neutron-rich nuclei {sup 32}Al and {sup 31}Al

    Energy Technology Data Exchange (ETDEWEB)

    Kameda, D., E-mail: kameda@ribf.riken.jp; Ueno, H. [RIKEN Nishina Center (Japan); Asahi, K.; Nagae, D.; Takemura, M.; Shimada, K. [Tokyo Institute of Technology, Department of Physics (Japan); Yoshimi, A.; Nagatomo, T.; Sugimoto, T. [RIKEN Nishina Center (Japan); Uchida, M.; Arai, T.; Takase, K.; Suda, S.; Inoue, T. [Tokyo Institute of Technology, Department of Physics (Japan); Murata, J.; Kawamura, H. [Rikkyo University, Department of Physics (Japan); Watanabe, H. [Australian National University, Department of Nuclear Physics (Australia); Kobayashi, Y.; Ishihara, M. [RIKEN Nishina Center (Japan)

    2007-11-15

    The electric quadrupole moments for the ground states of {sup 32}Al and {sup 31}Al have been measured by the {beta} ray-detected nuclear quadrupole resonance method. Spin-polarized {sup 32}Al and {sup 31}Al nuclei were obtained from the fragmentation of {sup 40}Ar projectiles at E/A = 95 MeV/nucleon, and were implanted in a single crystal {alpha}-Al{sub 2}O{sub 3} stopper. The measured Q moment of {sup 32}Al, |Q({sup 32}Al)| = 24(2) mb, is in good agreement with a conventional shell-model calculation with a full sd model space and empirical effective charges, while that of {sup 31}Al is considerably smaller than the sd calculations.

  8. The Y-Cu-Al system

    International Nuclear Information System (INIS)

    Krachan, T.; Stel'makhovych, B.; Kuz'ma, Yu.

    2003-01-01

    The phase diagram of the Y-Cu-Al system at 820 K has been constructed using X-ray powder diffraction. The existence of earlier known ternary aluminides has been confirmed and their homogeneity regions and atomic distributions in the structures have been determined: YCu 4.6-4.0 Al 7.4-8.0 (ThMn 12 -type R I =0.049), Y 2 Cu 12.0-10.5 Al 5.0-6.5 (Th 2 Zn 17 -type R I =0.092), YCu 1.0-1.1 Al 1.0-0.9 (Fe 2 P-type R I =0.068). It has been shown that the structure of Y(Cu,Al) 3 is characterized by an ordered distribution of the Cu and Al atoms and it should be referred as Ca 3 Cu 2 Al 7 structure type (R I =0.060) besides the PuNi 3 structure type with statistical occupancies of the smaller atoms. At the investigated temperature the compound YCu 1.0-0.25 Al 3.0-3.75 (BaAl 4 -type) was not observed. However, we found the ternary aluminide with composition Y 3 Cu 2.7-2.0 Al 8.3-9.0 and related La 3 Al 11 -type (space group Immm, a=0.4192-0.4228, b=1.2423-1.2557, c=0.9812-0.9895 nm, R I =0.069). The compounds YCu 6.8 Al 4.2 (space group Fddd, Tb(Cu 0.58 Al 0.42 ) 11 -type, a=1.42755, b=1.48587, c=0.65654 nm, R I =0.062) and YCu 6.5 Al 4.5 (space group I4 1 /amd, BaCd 11 -type, a=1.02774, c=0.65838 nm, R I =0.071) have been found and structurally refined for the first time

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

    Directory of Open Access Journals (Sweden)

    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

  10. KRITIK ATAS KRITIK EPISTEMOLOGI TAFSIR M. ABIED AL JABIRI: Studi Kritis atas Madkhal ila al Quran al Karim

    Directory of Open Access Journals (Sweden)

    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.

  11. Micromechanisms of fracture and fatigue in Ti3Al based and TiAl based intermetallics

    International Nuclear Information System (INIS)

    James, A.W.; Chave, R.A.; Hippsley, C.A.; Bowen, P.

    1993-01-01

    Micromechanisms of fracture and fatigue crack growth resistance in specific Ti 3 Al based and TiAl based intermetallics are reviewed. Effects of test temperature, environment and microstructure on crack growth resistance are considered in detail for several Ti 3 Al and Ti'Al based intermetallic systems under development. The implications of these studies for the structural reliability of these materials is also addressed briefly. (orig.)

  12. Density and atomic volume in liquid Al-Fe and Al-Ni binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Plevachuk, Yu. [Ivan Franko National Univ., Lviv (Ukraine). Dept. of Metal Physics; Egry, I.; Brillo, J.; Holland-Moritz, D. [Deutsches Zentrum fuer Luft- und Raumfahrt, Koeln (Germany). Inst. fuer Raumsimulation; Kaban, I. [Chemnitz Univ. of Technolgy (Germany). Inst. of Physics

    2007-02-15

    The density of liquid Al-Fe and Al-Ni binary alloys have been determined over a wide temperature range by a noncontact technique combining electromagnetic levitation and optical dilatometry. The temperature and composition dependences of the density are analysed. A negative excess volume correlates with the negative enthalpy of mixing, compound forming ability and chemical short-range ordering in liquid Al-Fe and Al-Ni alloys. (orig.)

  13. AL(0) in municipal waste incinerator ash

    Science.gov (United States)

    Stipp, S. L.; Ronsbo, J. G.; Zunic, T. B.; Christensen, T. H.

    2003-04-01

    Disposal of municipal waste is a challenge to society. Waste volume is substantially decreased by incineration but residual ash usually contains a number of toxic components which must be immobilised to insure environmental protection. One element, chromium, is mobile and toxic in its oxidised state as Cr(VI) but it can be reduced to Cr(III) and immobilised. Reduction can be promoted by ash treatment with Fe(0) or Fe(II), but recent evidence shows that at least some Cr(VI) is reduced spontaneously in the ash. Aspects of ash behaviour suggest metallic aluminium as the reducing agent, but no direct evidence of Al(0) has been found until now. We examined filter ash from an energy-producing, municipal-waste incinerator (Vest-forbrænding) near Copenhagen. X-ray diffraction (XRD) identified expected salts of Na, K and Ca such as halite, sylvite, calcite, anhydrite and gypsum as well as quartz, feldspar and some hematite. Wave-dispersive electron microprobe produced elemen-tal maps of the ash; Al-rich areas were analysed quantitatively by comparison with standards. We identified metallic Al particles, averaging 50 to 100 micrometers in di-ameter, often with a fractured, glassy border of aluminum oxide. The particles were porous, explaining fast Cr(VI) reduction and they contained thin exsolution lamellae of Al-alloys of Pb and Cu or Mn, Fe and Ag, which provide clues of the Al(0) origin in the waste. Sometimes Al(0) occurred inside glassy globes of Al2O3. Time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS) proved that surface Al concentrations on ash particles were below detection, confirming reactivity of the Al(0) bulk. The persistence of reduced Al through the highly oxidising combustion procedure comes as a surprise and is a benefit in the immobilisation of Cr(VI) from municipal-waste incineration residues.

  14. HOMENAJE AL DOCTOR JORGE CAVELIER

    Directory of Open Access Journals (Sweden)

    Guillermo Rueda Montaña

    1979-06-01

    ósitos. Jamás concibió nada pequeño, ni en lo material, ni en lo espiritual. Su propio mundo de acción y movimiento, tallado a su imagen y semejanza, no le permitía detenerse en pequeñeces. Cabalgaba
    contra el tiempo, y este no le era suficiente para sus designios. Por eso no podía detenerse en minucias, jamás fue mediocre, ni toleró la mediocridad.

    JORGE CAVELIER pasa al Panteón de los grandes de Colombia, su excepcional condición humana así lo impone, sus valiosos servicios a la Patria así lo demandan, y el profundo rastro que deja de su paso por la vida, así lo decide.

    La CRUZ ROJA COLOMBIANA, que le debe casi todo, ya no será la misma. Será imposible ocupar el inmenso vacío que deja la desaparición del titán. Ocuparemos su sitio, mas no lo reemplazaremos.
    Como las criaturas del bosque milenario, permaneceremos silenciosos y cavilantes ante el majestuoso y doloroso espectáculo de su caída.

    Descanse en Paz.

  15. 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

  16. Dakwah Kultural Bayt al-Qur’an al-Akbar Ukiran Kayu Khas Melayu Palembang

    Directory of Open Access Journals (Sweden)

    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.

  17. 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

  18. Computer aided cooling curve analysis for Al-5Si and Al-11Si alloys ...

    African Journals Online (AJOL)

    The effect of grain refiner, modifier, and combination of grain refiner cum modifier was studied on Al-5Si and Al-11Si alloys using computer aided cooling curve analysis. For combined grain refinement and modification effect, Al-Ti-B-Sr single master alloy was developed that acted as both grain refiner and modifier.

  19. 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.

  20. 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.

  1. Does Al Qaeda Central Still Matter?

    Directory of Open Access Journals (Sweden)

    Kangil Lee

    2015-01-01

    Full Text Available El artículo discute si Al Qaeda central es todavía relevante o no. Tras estudiar la actividades de Al Qaeda central cuyo objetivo es provocar la violencia en Afganistán y Pakistán, así como los planes continuos de ataques directos contra los Estados Unidos, el artículo muestra que la capacidad operativa de Al Qaeda es más sólida y fuerte que la que Estados Unidos y otros investigadores y eruditos han anticipado. Además, el apoyo virulento y la contribución Al Qaeda en la Península Arábiga a la red de Al Qaeda muestra que la longevidad de Al Qaeda depende de la relación con sus afiliados. El artículo concluye que, en estas condiciones, Al Qaeda central todavía ocupa un lugar en las discusiones de seguridad global.

  2. Al cation induces aggregation of serum proteins.

    Science.gov (United States)

    Chanphai, P; Kreplak, L; Tajmir-Riahi, H A

    2017-07-15

    Al cation is known to induce protein fibrillation and causes several neurodegenerative disorders. We report the spectroscopic, thermodynamic analysis and AFM imaging for the Al cation binding process with human serum albumin (HSA), bovine serum albumin (BSA) and milk beta-lactoglobulin (b-LG) in aqueous solution at physiological pH. Hydrophobicity played a major role in Al-protein interactions with more hydrophobic b-LG forming stronger Al-protein complexes. Thermodynamic parameters ΔS, ΔH and ΔG showed Al-protein bindings occur via hydrophobic and H-bonding contacts for b-LG, while van der Waals and H-bonding interactions prevail in HSA and BSA adducts. AFM clearly indicated that aluminum cations are able to force BSA and b-LG into larger or more robust aggregates than HSA, with HSA 4±0.2 (SE, n=801) proteins per aggregate, for BSA 17±2 (SE, n=148), and for b-LG 12±3 (SE, n=151). Thioflavin T test showed no major protein fibrillation in the presence of Al cation. Al complexation induced major alterations of protein conformations with the order of perturbations b-LG>BSA>HSA. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Strength of Al and Al-Mg/alumina bonds prepared using ultrahigh vacuum diffusion bonding

    International Nuclear Information System (INIS)

    King, W.E.; Campbell, G.H.; Wien, W.L.; Stoner, S.L.

    1994-01-01

    The authors have measured the cross-breaking strength of Al and Al-Mg alloys bonded with alumina. Diffusion bonding of Al and Al-Mg alloys requires significantly more bonding time than previously thought to obtain complete bonding. In contrast to previous diffusion bonding studies, fracture morphologies are similar to those obtained in bonds formed by liquid phase reaction; i.e., bonds are as strong or stronger than the ceramic; and fracture tends to propagate in the metal for pure Al and near the interface in the ceramic for the alloys. There are indications that the fracture morphology depends on Mg content and therefore on plasticity in the metal

  4. [Lessons from Guam ALS/PDC study].

    Science.gov (United States)

    Asao, Hirano

    2007-11-01

    An extraordinarily high incidence of amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC) affecting the native population was discovered on the island of Guam a half century ago. Guam ALS is identical to classic ALS clinically and pathologically while PDC is marked by progressive parkinsonism and dementia. The unusual histological finding in these fetal neurodegenerative diseases is the presence of numerous neurofibrillary tangles in a selective topographic distribution unassociated with senile plaques. There have been remarkable advances in field of age-associated neurodegenerative disease after our initial study of Guam cases. Four noteworthy topics are presented in this communication. 1) Clinically, the coexistence of parkinsonism and dementia was frequently recognized in Parkinson disease and Alzheimer disease. Some other new disease entities characterized by coexistence of parkinsonism and dementia have been reported. These include progressive supranuclear palsy, frontotemporal dementia and parkinsonism linked to chromosome 17. 2) Neuropathologically, abundant neurofibrillary tangles unassociated with senile plaques were demonstrated in many diseases such as aftermath of boxing and tangle-only dementia. Furthermore, tau-positive structures were recognized not only in neurons but in glial cells in certain diseases. Tauopathy is one of the current hot research subjects. 3) Familial aggregation of Guam ALS patients provoked investigation of familial ALS elsewhere. Familial motor neuron disease with SOD1 mutation is the target of worldwide intense investigation at the present time. SOD1 gene mutation is, however, not found in Guam ALS. 4) The most striking findings of the Guam study is the gradual decline in the incidence of ALS on Guam during a quarter century and virtual disappearance of new patients. This may be linked to a remarkable change in environment and life style of the Chamorro population. The etiology of ALS is still unknown and

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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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.' ' '

  7. Optical, structural, and nuclear scientific studies of AlGaN with high Al composition

    Science.gov (United States)

    Lin, Tse Yang; Chung, Yee Ling; Li, Lin; Yao, Shude; Lee, Y. C.; Feng, Zhe Chuan; Ferguson, Ian T.; Lu, Weijie

    2010-08-01

    AlGaN epilayers with higher Al-compositions were grown by Metalorganic Chemical Vapor Deposition (MOCVD) on (0001) sapphire. Trimethylgallium (TMGa), trimethylaluminium (TMAl) and NH3 were used as the source precursors for Ga, Al, and N, respectively. A 25 nm AlN nucleation layer was first grown at low-temperature of 590 °C at 300 Torr. Followed, AlxGa1-xN layers were grown at 1080 °C on low-temperature AlN nucleation layers. The heterostructures were characterized by a series of techniques, including x-ray diffraction (XRD), Rutherford backscattering (RBS), photoluminescence (PL), scanning electron microscopy (SEM) and Raman scattering. Precise Al compositions were determined through XRD, RBS, and SEM combined measurements. Room Temperature Raman Scattering spectra shows three major bands from AlGaN alloys, which are AlN-like, A1 longitudinal optical (LO) phonon modes, and E2 transverse optical (TO) band, respectively, plus several peak comes from the substrate. Raman spectral line shape analysis lead to an optical determination of the electrical property free carrier concentration of AlGaN. The optical properties of AlGaN with high Al composition were presented here.

  8. Formation of epitaxial Al 2O 3/NiAl(1 1 0) films: aluminium deposition

    Science.gov (United States)

    Lykhach, Y.; Moroz, V.; Yoshitake, M.

    2005-02-01

    Structure of epitaxial Al 2O 3 layers formed on NiAl(1 1 0) substrates has been studied by means of reflection high-energy electron diffraction (RHEED). The elucidated structure was compared to the model suggested for 0.5 nm-thick Al 2O 3 layers [K. Müller, H. Lindner, D.M. Zehner, G. Ownby, Verh. Dtsch. Phys. Ges. 25 (1990) 1130; R.M. Jaeger, H. Kuhlenbeck, H.J. Freund, Surf. Sci. 259 (1991) 235]. The stepwise growth of Al 2O 3 film, involving deposition and subsequent oxidation of aluminium onto epitaxial 0.5 nm-thick Al 2O 3 layers, has been investigated. Aluminium was deposited at room temperature, whereas its oxidation took place during annealing at 1070 K. The Al 2O 3 thickness was monitored by means of Auger electron spectroscopy (AES). It was found that Al 2O 3 layer follows the structure of 0.5 nm thick Al 2O 3 film, although a tilting of Al 2O 3(1 1 1) surface plane with respect to NiAl(1 1 0) surface appeared after Al deposition.

  9. 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...

  10. Some aspects of anelastic and microplastic creep of pure Al and two Al-alloys

    International Nuclear Information System (INIS)

    Sgobba, S.; Kuenzi, H.U.; Ilschner, B.

    1993-01-01

    Anelastic creep of pure Al, commercial Al-Cu and a binary Al-Cu alloy has been measured at room temperature by means of a high resolution laser interferometer. The irreversible component of the deformation was also quantified from measurements of the anelastic creep recovery. The dependence of the deformation-time curves on thermal treatment and cold work is analyzed. The mechanisms responsible for the room temperature anelastic creep are discussed. Materials loaded below their elastic limit can present either a pure anelastic behavior (commercial Al-Cu) or additional viscoelastic creep (pure Al, high purity Al-Cu). For commercial Al-Cu, the presence of an irreversible deformation appears to be mainly related to the state of the surface. A viscoelastic after effect has been measured for this alloy after a Cu-electroplating treatment. As a typical result for room temperature creep, the irreversible deformation depends logarithmically on load time. (orig.)

  11. Some aspects of anelastic and microplastic creep of pure Al and two Al-alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sgobba, S. (Lab. de Metallurgie Mecanique, Dept. des Materiaux, Ecole Polytechnique Federale de Lausanne (Switzerland)); Kuenzi, H.U. (Lab. de Metallurgie Mecanique, Dept. des Materiaux, Ecole Polytechnique Federale de Lausanne (Switzerland)); Ilschner, B. (Lab. de Metallurgie Mecanique, Dept. des Materiaux, Ecole Polytechnique Federale de Lausanne (Switzerland))

    1993-11-01

    Anelastic creep of pure Al, commercial Al-Cu and a binary Al-Cu alloy has been measured at room temperature by means of a high resolution laser interferometer. The irreversible component of the deformation was also quantified from measurements of the anelastic creep recovery. The dependence of the deformation-time curves on thermal treatment and cold work is analyzed. The mechanisms responsible for the room temperature anelastic creep are discussed. Materials loaded below their elastic limit can present either a pure anelastic behavior (commercial Al-Cu) or additional viscoelastic creep (pure Al, high purity Al-Cu). For commercial Al-Cu, the presence of an irreversible deformation appears to be mainly related to the state of the surface. A viscoelastic after effect has been measured for this alloy after a Cu-electroplating treatment. As a typical result for room temperature creep, the irreversible deformation depends logarithmically on load time. (orig.).

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 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

  14. High Temperature AL-Nanocrystal Alloy Synthesis

    National Research Council Canada - National Science Library

    Perepezko, J

    2001-01-01

    Aluminum-rich metallic glasses containing transition metals and rare earth elements have been found to yield finely mixed microstructures of Al nanocrystals embedded in an amorphous matrix and exhibit...

  15. Landbouwprotectie als middel tot politieke integratie.

    NARCIS (Netherlands)

    Noort, van den P.C.

    1988-01-01

    In acht hoofdstukken is dit beleid uiteengezet. 1. Landbouwprotectie als middel tot politieke integratie. 2. Eigenbelang van een meer marktgericht landbouwbeleid. 3. uitdagingen voor landbouwcooperaties. 4. Het westers landbouwbeleid en het wereldvoedselprobleem. 5. Landbouw heeft nu een eigen

  16. (14) Akinwole et al Influence of Culture

    African Journals Online (AJOL)

    Adeyinka Odunsi

    Influence of Culture Water Draw-off on Growth of the African ... 1Department of Aquaculture and Fisheries Management, University of ... areas (Eyo et al., 2003). .... systems. Nigerian Journal of Rural. Extension and Development. 6: 38-. 42.

  17. Al Qaeda: Statements and Evolving Ideology

    National Research Council Canada - National Science Library

    Blanchard, Christopher M

    2004-01-01

    ... [April and October 2004] have led some terrorism analysts to speculate that the messages may signal a new attempt by him to create a lasting political leadership role for himself and Al Qaeda as the vanguard...

  18. Grain boundaries in Ni3Al. 2

    International Nuclear Information System (INIS)

    Kung, H.; Sass, S.L.

    1992-01-01

    This paper discusses the dislocation structure of small angle tilt and twist boundaries in ordered Ni 3 Al, with and without boron, investigated using transmission electron microscopy. Dislocation with Burgers vectors that correspond to anti-phase boundary (APB)-coupled superpartials were found in small angle twist boundaries in both boron-free and boron-doped Ni 3 Al, and a small angle tilt boundary in boron-doped Ni 3 Al. The boundary structures are in agreement with theoretical models proposed by Marcinkowski and co-workers. The APB energy determined from the dissociation of the grain boundary dislocations was lower than values reported for isolated APBs in Ni 3 Al. For small angle twist boundaries the presence of boron reduced the APB energy at the interface until it approached zero. This is consistent with the structure of these boundaries containing small regions of increased compositional disorder in the first atomic plane next to the interface

  19. 12th Annual ALS Users' Association Meeting

    International Nuclear Information System (INIS)

    Robinson, Arthur L.

    1999-01-01

    Science took the front seat as 219 Advanced Light Source (ALS) users and staff gathered on Monday and Tuesday, October 18 and 19 for the twelfth annual users' meeting. The bulk of the meeting was dedicated to reports on science at the ALS. Packed into two busy days were 31 invited oral presentations and 80 submitted poster presentations, as well as time to visit 24 vendor booths. The oral sessions were dedicated to environmental science, chemical dynamics, biosciences, magnetic materials, and atomic and molecular science. In addition, there was an ALS highlights session that emphasized new results and a session comprising highlights from the young scientists who will carry the ALS into the future

  20. AL Amyloidosis Complicated by Persistent Oral Bleeding

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Liarte Marconcini

    2015-01-01

    Full Text Available A case of amyloid light chain (AL amyloidosis is presented here with uncontrolled bleeding after a nonsurgical dental procedure, most likely multifactorial in nature, and consequently treated with a multidisciplinary approach.

  1. Arfiputri et al., Afr., J. Infect. Dis.

    African Journals Online (AJOL)

    Dharin Serebrina Arfiputri

    2017-10-20

    Oct 20, 2017 ... Diagnosis of VVC are from history taking, physical examination (Linhares et al, 2001; ... From the appearance of vaginal discharge usually minimal, ... (69.48%), and the rest are not yet married, divorce and widow, not yet.

  2. Ayinmode et al., Afr., J. Infect. Dis.

    African Journals Online (AJOL)

    Ayinmode, Adekunle

    Brucella abortus antibodies using Rose Bengal test and Competitive Enzyme Linked ... milk production in both dairy and beef cattle (Hernandez et al., 2001; Dubey and Schares, 2011). ..... Institut National de la Recherche Agronomique. Paris ...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  5. Performance of the ALS injection system

    International Nuclear Information System (INIS)

    Kim, C.H.

    1993-05-01

    The authors started commissioning the Advanced Light Source (ALS) storage ring on January 11, 1993. The stored beam reached 60 mA on March 24, 1993 and 407 mA on April 9, 1993. The fast pace of storage ring commissioning can be attributed partially to the robust injection system. In this paper they describe the operating characteristics of the ALS injection system

  6. The evolving genetic risk for sporadic ALS.

    Science.gov (United States)

    Gibson, Summer B; Downie, Jonathan M; Tsetsou, Spyridoula; Feusier, Julie E; Figueroa, Karla P; Bromberg, Mark B; Jorde, Lynn B; Pulst, Stefan M

    2017-07-18

    To estimate the genetic risk conferred by known amyotrophic lateral sclerosis (ALS)-associated genes to the pathogenesis of sporadic ALS (SALS) using variant allele frequencies combined with predicted variant pathogenicity. Whole exome sequencing and repeat expansion PCR of C9orf72 and ATXN2 were performed on 87 patients of European ancestry with SALS seen at the University of Utah. DNA variants that change the protein coding sequence of 31 ALS-associated genes were annotated to determine which were rare and deleterious as predicted by MetaSVM. The percentage of patients with SALS with a rare and deleterious variant or repeat expansion in an ALS-associated gene was calculated. An odds ratio analysis was performed comparing the burden of ALS-associated genes in patients with SALS vs 324 normal controls. Nineteen rare nonsynonymous variants in an ALS-associated gene, 2 of which were found in 2 different individuals, were identified in 21 patients with SALS. Further, 5 deleterious C9orf72 and 2 ATXN2 repeat expansions were identified. A total of 17.2% of patients with SALS had a rare and deleterious variant or repeat expansion in an ALS-associated gene. The genetic burden of ALS-associated genes in patients with SALS as predicted by MetaSVM was significantly higher than in normal controls. Previous analyses have identified SALS-predisposing variants only in terms of their rarity in normal control populations. By incorporating variant pathogenicity as well as variant frequency, we demonstrated that the genetic risk contributed by these genes for SALS is substantially lower than previous estimates. © 2017 American Academy of Neurology.

  7. Thermoluminescence properties of AlN ceramics

    DEFF Research Database (Denmark)

    Trinkler, L.; Christensen, P.; Agersnap Larsen, N.

    1998-01-01

    The paper describes thermoluminescence (TL) properties of AlN:Y2O3 ceramics irradiated with ionising radiation. A high TL sensitivity of AlN:Y2O3 ceramics to radiation encouraged a study of the AlN ceramics for application as a dosimetric material. The paper presents experimental data on: glow...... curve, emission spectrum, dose response, energy dependence, influence of heating rate and fading rate. The measured TL characteristics were compared with those of well-known, widely used TLDs, i.e. LiF:Mg,Ti, LiF:Mg,Cu,P and Al2O3:C. It is concluded that AlN:Y2O3 ceramics showing a radiation sensitivity...... which is approximately 50 times greater than that of LiF:Mg,Ti is an interesting dosimetry material; however due to a high fading rate of the TL of AlN:Y2O3 on storage at room temperature, a further development of the material for improving the fading characteristics is needed for its application...

  8. Clinical trials for neuroprotection in ALS.

    Science.gov (United States)

    Siciliano, G; Carlesi, C; Pasquali, L; Piazza, S; Pietracupa, S; Fornai, F; Ruggieri, S; Murri, L

    2010-07-01

    Owing to uncertainty on the pathogenic mechanisms underlying motor neuron degeneration in amyotrophic lateral sclerosis (ALS) riluzole remains the only available therapy, with only marginal effects on disease survival. Here we review some of the recent advances in the search for disease-modifying drugs for ALS based on their putative neuroprotective effetcs. A number of more or less established agents have recently been investigated also in ALS for their potential role in neuroprotection and relying on antiglutamatergic, antioxidant or antiapoptotic strategies. Among them Talampanel, beta-lactam antibiotics, Coenzyme Q10, and minocycline have been investigated. Progress has also been made in exploiting growth factors for the treatment of ALS, partly due to advances in developing effective delivery systems to the central nervous system. A number of new therapies have also been identified, including a novel class of compounds, such as heat-shock protein co-inducers, which upregulate cell stress responses, and agents promoting autophagy and mitochondriogenesis, such as lithium and rapamycin. More recently, alterations of mRNA processing were described as a pathogenic mechanism in genetically defined forms of ALS, as those related to TDP-43 and FUS-TLS gene mutations. This knowledge is expected to improve our understanding of the pathogenetic mechanism in ALS and developing more effective therapies.

  9. The fecal microbiome of ALS patients.

    Science.gov (United States)

    Brenner, David; Hiergeist, Andreas; Adis, Carolin; Mayer, Benjamin; Gessner, André; Ludolph, Albert C; Weishaupt, Jochen H

    2018-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative motor neuron disease accompanied by both systemic and central nervous system-specific inflammation as well as deregulated energy metabolism. These potential pathogenetic factors have recently been found to mutually interact with the gut microbiota, raising the hypothesis of a link between microbiome alterations and ALS pathogenesis. The aim of our study was to assess whether ALS is associated with an altered composition of the fecal microbiota. We compared the fecal microbiota of 25 ALS patients with 32 age- and gender-matched healthy persons using 16S rRNA gene sequencing analysis. Confounding factors and secondary disease effects on the microbiome were minimized by selection of patients without dysphagia, gastrostomy, noninvasive ventilation, or reduced body mass index. Comparing the 2 carefully matched groups, the diversity and the abundance of the bacterial taxa on the different taxonomic levels as well as PICRUSt-predicted metagenomes were almost indistinguishable. Significant differences between ALS patients and healthy controls were only observed with regard to the overall number of microbial species (operational taxonomic units) and in the abundance of uncultured Ruminococcaceae. Conclusively, ALS patients do not exhibit a substantial alteration of the gut microbiota composition. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Heterogeneous nucleation of solid Al from the melt by Al 3 Ti : Molecular dynamics simulations

    KAUST Repository

    Wang, Junsheng; Horsfield, Andrew; Lee, Peter D.; Brommer, Peter

    2010-01-01

    It has been known experimentally for some time that Al3 Ti is a powerful nucleant for the solidification of aluminum from the melt; however, a full microscopic understanding is still lacking. To develop this understanding, we have performed molecular dynamics simulations of the nucleation and early stages of growth using published embedded atom method potentials for Al-Ti, but modified by us to stabilize the D 022 structure. We discover that Al3 Ti can indeed be very effective in promoting the growth of solid Al but the manner in which growth takes place depends sensitively on the surface on which the Al nucleates. In particular, complete growth of solid Al from the liquid on the (001) and (110) surfaces of Al3 Ti occurs at a lower temperature than on the (112) surface. This anisotropy agrees with observations in previous experiments. We explain this observation in terms of interfacial energies. On the preferential (111) surface of Al the solid-liquid interfacial energy is highest while the solid-vacuum energy is lowest. Our simulations also show that the extent of ordering taking place in liquid Al close to the Al 3 Ti substrate above the melting point correlates well with the effectiveness of the substrate as a nucleant below the melting temperature: this could provide a computationally efficient scheme to identify good nucleants. © 2010 The American Physical Society.

  11. Compressive performance and crack propagation in Al alloy/Ti{sub 2}AlC composites

    Energy Technology Data Exchange (ETDEWEB)

    Hanaor, D.A.H., E-mail: dorian.hanaor@sydney.edu.au [School of Civil Engineering, University of Sydney, Sydney, NSW 2006 (Australia); Hu, L. [Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Kan, W.H.; Proust, G. [School of Civil Engineering, University of Sydney, Sydney, NSW 2006 (Australia); Foley, M. [Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, NSW 2006 (Australia); Karaman, I.; Radovic, M. [Department of Materials Science and Engineering, Texas A& M University, College Station, TX 77843 (United States)

    2016-08-30

    Composite materials comprising a porous Ti{sub 2}AlC matrix and Al 6061 alloy were fabricated by a current-activated pressure assisted melt infiltration process. Coarse, medium and fine meso-structures were prepared with Al alloy filled pores of differing sizes. Materials were subjected to uniaxial compressive loading up to stresses of 668 MPa, leading to the failure of specimens through crack propagation in both phases. As-fabricated and post-failure specimens were analysed by X-ray microscopy and electron microscopy. Quasi-static mechanical testing results revealed that compressive strength was the highest in the fine structured composite materials. While the coarse structured specimens exhibited a compressive strength of 80% relative to this. Reconstructed micro-scale X-ray tomography data revealed different crack propagation mechanisms. Large planar shear cracks propagated throughout the fine structured materials while the coarser specimens exhibited networks of branching cracks propagating preferentially along Al alloy-Ti{sub 2}AlC phase interfaces and through shrinkage pores in the Al alloy phase. Results suggest that control of porosity, compensation for Al alloy shrinkage and enhancement of the Al alloy-Ti{sub 2}AlC phase interfaces are key considerations in the design of high performance metal/Ti{sub 2}AlC phase composites.

  12. 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

  13. Heterogeneous nucleation of solid Al from the melt by Al 3 Ti : Molecular dynamics simulations

    KAUST Repository

    Wang, Junsheng

    2010-10-27

    It has been known experimentally for some time that Al3 Ti is a powerful nucleant for the solidification of aluminum from the melt; however, a full microscopic understanding is still lacking. To develop this understanding, we have performed molecular dynamics simulations of the nucleation and early stages of growth using published embedded atom method potentials for Al-Ti, but modified by us to stabilize the D 022 structure. We discover that Al3 Ti can indeed be very effective in promoting the growth of solid Al but the manner in which growth takes place depends sensitively on the surface on which the Al nucleates. In particular, complete growth of solid Al from the liquid on the (001) and (110) surfaces of Al3 Ti occurs at a lower temperature than on the (112) surface. This anisotropy agrees with observations in previous experiments. We explain this observation in terms of interfacial energies. On the preferential (111) surface of Al the solid-liquid interfacial energy is highest while the solid-vacuum energy is lowest. Our simulations also show that the extent of ordering taking place in liquid Al close to the Al 3 Ti substrate above the melting point correlates well with the effectiveness of the substrate as a nucleant below the melting temperature: this could provide a computationally efficient scheme to identify good nucleants. © 2010 The American Physical Society.

  14. Predicting glass-forming compositions in the Al-La and Al-La-Ni systems

    International Nuclear Information System (INIS)

    Gargarella, P.; de Oliveira, M.F.; Kiminami, C.S.; Pauly, S.; Kuehn, U.; Bolfarini, C.; Botta, W.J.; Eckert, J.

    2011-01-01

    Research highlights: → The glass-forming ability of the Al-La and Al-La-Ni systems was studied using the λ* and the λ.Δe criteria. → Both criteria predicted with just 1% at. of error the best glass-former verified so far in the Al-La system. → Four new glass-former compositions could be predicted in the Al-La-Ni system using the λ.Δe criterion. → The best glass-former reported so far in the Al-La-Ni system was found. - Abstract: In this work, a criterion considering the topological instability (λ) and the differences in the electronegativity of the constituent elements (Δe) was applied to the Al-La and Al-Ni-La systems in order to predict the best glass-forming compositions. The results were compared with literature data and with our own experimental data for the Al-La-Ni system. The alloy described in the literature as the best glass former in the Al-La system is located near the point with local maximum for the λ.Δe criterion. A good agreement was found between the predictions of the λ.Δe criterion and literature data in the Al-La-Ni system, with the region of the best glass-forming ability (GFA) and largest supercooled liquid region (ΔT x ) coinciding with the best compositional region for amorphization indicated by the λ.Δe criterion. Four new glassy compositions were found in the Al-La-Ni system, with the best predicted composition presenting the best glass-forming ability observed so far for this system. Although the λ.Δe criterion needs further refinements for completely describe the glass-forming ability in the Al-La and Al-La-Ni systems, the results demonstrated that this criterion is a good tool to predict new glass-forming compositions.

  15. 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.

  16. 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)

  17. Effect of elevated Al and pH on the growth and root morphology of Al-tolerant and Al-sensitive wheat seedlings in an acid soil

    Directory of Open Access Journals (Sweden)

    Md. Toufiq Iqbal

    2014-03-01

    Full Text Available Aluminium ion (Al3+ toxicity and hydrogen ion (H+ activity are the major constraints for plant growth in acid soil. This study was undertaken to determine the effect of pH and Al on the growth response and changes in root morphology of Al-tolerant (ET8 and Al-sensitive (ES8 wheat seedlings. Different levels of AlCl3 and CaCO3 were added to the soils to manipulate soil pH and extractable Al. The results showed that the bulk soil pH remained constant at pH 4.1 with further applications of AlCl3, and that the seedlings died at the 200 mg AlCl3/kg treatments. The ET8 seedlings responded better than the ES8 seedlings in both low and high Al and pH. The ET8 seedlings had higher root surface areas and root tip numbers than the ES8 seedlings in the Al treatment. In contrast, the ES8 had higher root diameters than the ET8 seedlings due to the elevated Al supply. Apoplast Al increased with the increase of soil available extractable Al, and declined with the decrease of soil extractable Al. The ET8 seedlings accumulated more Al in their apoplast than the ES8 seedlings. This study concluded that accumulation of Al in the apoplast is also involved in Al tolerance mechanism with the addition of organic acid exudation.

  18. Disordered crystal structure of 20H-AlON, Al10O3N8

    International Nuclear Information System (INIS)

    Banno, Hiroki; Funahashi, Shiro; Asaka, Toru; Hirosaki, Naoto; Fukuda, Koichiro

    2015-01-01

    The disordered crystal structure of 20H-AlON (Al 10 O 3 N 8 ) was determined by combined use of X-ray powder diffraction and transmission electron microscopy. The title compound is hexagonal with space group P6 3 /mmc (Z=2) and the unit-cell dimensions are a=0.307082(5) nm, c=5.29447(8) nm and V=0.432376(12) nm 3 . The structural model showed the positional disordering of three of the six Al sites in the unit cell. The reliability indices calculated from the Rietveld method were R wp =6.97%, S (=R wp /R e )=1.68, R p =5.45%, R B =5.13% and R F =4.56%. We interpreted the disordered structure of 20H-AlON as a statistical average of six different types of ordered structural configurations, which are composed of an octahedral [Al(O, N) 6 ] layer and tetrahedral [Al(O, N) 4 ] layers. We demonstrated the high correlations between the hexagonal unit-cell dimensions and the octahedral layer concentrations for AlON and SiAlON polytypoids. - Graphical abstract: Variations of a and c/(n O +n T ) with n O /(n O +n T ). The a and c are the hexagonal unit-cell dimensions of AlON, SiAlON and AlN. The n O and n T are, respectively, the numbers of octahedral and tetrahedral layers in the unit cells. The unit-cell dimensions in literature are plotted in black plus for AlON and black cross for SiAlON. The unit-cell dimensions of AlN are a=0.3110 nm and c=0.4980 nm. - Highlights: • Crystal structure of Al10O3N8 is determined by laboratory X-ray powder diffraction. • The atom arrangements are represented by the split-atom model. • Six types of ordered atom arrangements are derived from the disordered structure. • Hexagonal unit-cell dimensions changed systematically for AlON and SiAlON compounds

  19. Ilhaq al-Masa'il bi Nazairiha dan Penerapannya dalam Bahth al-Masa'il

    Directory of Open Access Journals (Sweden)

    Luthfi Hadi Aminuddin

    2013-11-01

    Full Text Available Abstract: Ilh}a>q al-Masa>’il bi Naz}a>iriha is one of the methods used by Nahdlatul Ulama in resisting the opinion based on (manhaji analytical concept of Islamic jurisprudence (the solution for complex social problems as the main purpose of Islamic shari’ah. As known that, up to now, ilh}a>q has been understood as a process of answering a new case by the way of equating to the old one which is written in the book called al-mu’tabarah. Such ilh}a>q has got many criticisms both from the definitions, procedures and its epistemogical footing. This paper is about to reveal how the NU clerics of Islam understand the concept of Ilh}a>q}, what its epistemological footing was and how the concept was applied in discussing many cases (bah}th al-masa>’il. Based on the writer’s study to several documents of decision results of NU that Ilh}a>q did not only simplify to equate the new cases with the old ones that have been freely discussed in the books of al-mu’tabarah, but both cases should have similar legal substance, that is, both should be under the decrees of laws of al-qawa> ‘id al-fiqhi>yah. Thus, Ilh}a>q is actually answering the problem by applying al-qawa>‘id al-fiqhi>yah, whereas the formulation al-qawa>‘id al-fiqhi>yah itself was set off from the examination of a number of furu>’ generated by qiya> s. This paper also found three variations of the implementation of Ilh}a>q in bah}th al-masa>’il. First, the application of Ilh}a>q was without mentioning al-qawa> ‘id al-fiqhi>yah which covered new cases (mulh}aq and the old case law that has been known in the books of fiqh (mulh}aq bih/attached to. Second, the application of Ilh}a>q was accompanied by mentioning mulh}aq bih and al-qawa> ‘id al-fiqhi>yah. Third, the application of Ilh}a>q, was only by the mentioning al-qawa> ‘id al-fiqhi>yah.

  20. Prinsip Pendidikan Karakter dalam Islam: Studi Komparasi Pemikiran Al-Ghazali dan Burhanuddin Al-Zarnuji

    Directory of Open Access Journals (Sweden)

    Agus Setiawan

    2014-06-01

    Full Text Available The impelemtantion of character education that is done by the Indonesian government recently has been provoked by al-Ghazali and Burhanuddin al-Zarnuji long ago. It was proven by some written thoughts of al-Ghazali and Burhanuddin al-Zarnuji. They were very famous scientists in their era and widely welknown as educational experts who produced some phenomenal thoughts many people use today. Al-Ghazali and Burhanuddin al-Zarnuji lived in the era of Bani Abbasiyah monarchy, but Both of them lived in different era. Al-Ghazali was born first, then Burhanuddin al-Zarnuji. They had different mazhab, al-Ghazali went to the traditional principle of mazhab Syafi’I and Burhanuddin al-Zarnuji went to the modern principle of mazhab Hanafi. The differences, of course, would create a different thought. Still, they might have a similar principle of Islamic character education. The thoughts of character education of al-Ghazali have been poured in the “Ayyuha Walad” focusing to the students’ character building characterized by religiously obedient, skillfull of general and religious knowledge, socially helpful, affectionate, generous, good citizen, and coloring the society. Some applicable thoughts of character education of Ayyuha al-Walad of al-Gazhali to the contemporary education are: the balance of the happiness purposes of the recent life and the life after death, qana’ah and tawakal, affectionate, caring other, patience, honesty, philanthrophy, social works, generousity, democratic, peace makers, and patriotic. Those characters are also directed in the islamic character education nowdays. So that, the thoughts of al-Ghazali positively and responsively are absorbed by the Indonesian government to build the national character widely implementing in the national curriculum based on the local wisdom and the Islamic values. In the end, the students are able to live happily based on the Islamic rules by implementing the good behavior. Similar to the al

  1. Alpha and beta stabilizer character of Al in Zr-Nb-Al alloys

    International Nuclear Information System (INIS)

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

    1987-01-01

    The T β/α+β of Zr5Nb and Zr5Nb2Al (weight %) were determined in order to observe the alpha-stabilizer character of Al in ternary Zr-Nb-Al alloys. Techniques employed were change of resistivity with temperature in dynamic experiences, and metallography of samples quenched to room temperature after isothermal annealings. The T β/α+β of the ternary resulted 17 ± 8 deg C higher than that of the binary alloy. In addition, taking into account the results of previous investigations of the transformation of beta on quenching Zr-Nb-Al alloys from the beta field to room temperature, it is concluded that the beta-stabilizer character of Nb is stronger than the alpha-stabilizer character of Al in these Zr alloys, and that the Al can have important influence on the mechanical properties by the appearance of TRIP effect. (Author) [es

  2. 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.

  3. Effects of Al(III and Nano-Al13 Species on Malate Dehydrogenase Activity

    Directory of Open Access Journals (Sweden)

    Rong Fu Chen

    2011-05-01

    Full Text Available The effects of different aluminum species on malate dehydrogenase (MDH activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT modified glass carbon electrode (GCE. The results showed that Al(III and Al13 can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III and Al13 concentration increase. Our study also found that the effects of Al(III and Al13 on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules.

  4. Effects of Al(III) and nano-Al13 species on malate dehydrogenase activity.

    Science.gov (United States)

    Yang, Xiaodi; Cai, Ling; Peng, Yu; Li, Huihui; Chen, Rong Fu; Shen, Ren Fang

    2011-01-01

    The effects of different aluminum species on malate dehydrogenase (MDH) activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT) modified glass carbon electrode (GCE). The results showed that Al(III) and Al(13) can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al(13) concentration increase. Our study also found that the effects of Al(III) and Al(13) on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules.

  5. 60Co gamma radiation effect on AlGaN//AlN/GaN HEMT devices

    International Nuclear Information System (INIS)

    Wang Yanping; Luo Yinhong; Wang Wei; Zhang Keying; Guo Hongxia; Guo Xiaoqiang; Wang Yuanming

    2013-01-01

    The testing techniques and experimental methods of the 60 Co gamma irradiation effect on AlGaN/AlN/GaN high electron mobility transistors (HEMTs) are established. The degradation of the electrical properties of the device under the actual radiation environment are analyzed theoretically, and studies of the total dose effects of gamma radiation on AlGaN/AlN/GaN HEMTs at three different radiation bias conditions are carried out. The degradation patterns of the main parameters of the AlGaN/AlN/GaN HEMTs at different doses are then investigated, and the device parameters that were sensitive to the gamma radiation induced damage and the total dose level induced device damage are obtained. (authors)

  6. 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 .

  7. Potential skin involvement in ALS: revisiting Charcot's observation - a review of skin abnormalities in ALS.

    Science.gov (United States)

    Paré, Bastien; Gros-Louis, François

    2017-07-26

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting motor neurons of the brain and spinal cord, leading to progressive paralysis and death. Interestingly, many skin changes have been reported in ALS patients, but never as yet fully explained. These observations could be due to the common embryonic origin of the skin and neural tissue known as the ectodermal germ layer. Following the first observation in ALS patients' skin by Dr Charcot in the 19th century, in the absence of bedsores unlike other bedridden patients, other morphological and molecular changes have been observed. Thus, the skin could be of interest in the study of ALS and other neurodegenerative diseases. This review summarizes skin changes reported in the literature over the years and discusses about a novel in vitro ALS tissue-engineered skin model, derived from patients, for the study of ALS.

  8. A note on Wang et al's attack on Zhang et al's multiparty quantum secret sharing

    International Nuclear Information System (INIS)

    Gao Gan

    2012-01-01

    Recently, Wang et al (2008 Phys. Lett. A 373 65) proposed an attack on Zhang et al's (2007 Opt. Commun. 269 418) multiparty quantum secret sharing scheme, in which the first and the last agent are reported to be able to cooperatively eavesdrop on all the secret messages without being detected. In this paper, we show that in Wang et al's attack, on average no more than half the secret messages can be eavesdropped. (paper)

  9. Effect of the interface in laminated composites of Al-1100 and Al-2024

    International Nuclear Information System (INIS)

    Godefroid, L.B.

    1983-01-01

    Laminated composites consisting of alternating layers of Al-1100 and Al-2024 were produced by hot rolling, with 45% Al-2024 volume fraction. These composites were subjected to cyclic thermal treatment (various numbers of cycles) and to isothermal treatment (various numbers of cycles) and to isothermal treatment (at peak temperature and for times equivalent to those of the thermal cycles. Microhardness, tensile and fatigue crack arrester modes) were studied in the initial state and after treatments. (E.G.) [pt

  10. 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.

  11. Solutional Landforms of Gabal Al-Qaraha, the Oasis of Al-Hasa, Saudi Arabia

    OpenAIRE

    Embabi, Nabil S.

    1981-01-01

    Jabal Al-Qarah is one of the small outlier hills at the Oasis of Al-Hasa, lying at about lOkm ENE of Al-Hafuf Town. The solutional forms of Al-Qarah hill discussed in this paper are as follows : 1. A calcareous duricrust which covers the top and some of the slopes of the hill. 2. Rock Pillars which are long columns of white lime-stone. 3. Huge crevasses which are wide erosional openings along vertical joints. 4. Narrow, sinuous caves inside the hill. 5. Pedestal rocks with mushroo...

  12. Tetragonal phase in Al-rich region of U-Fe-Al system

    International Nuclear Information System (INIS)

    Meshi, L.; Zenou, V.; Ezersky, V.; Munitz, A.; Talianker, M.

    2005-01-01

    A new ternary aluminide U 2 FeAl 20 with the approximate composition Al-4.2at% Fe-8.5at% U was observed in the Al-rich corner of the U-Al-Fe system. Transmission electron microscopy and electron microdiffraction technique were used for characterization of the structure of this phase. It has a tetragonal unit cell with the parameters a=12.4A and c=10.3A and can be described by the space group I4-bar 2m

  13. Study on Mg/Al Weld Seam Based on Zn–Mg–Al Ternary Alloy

    Directory of Open Access Journals (Sweden)

    Liming Liu

    2014-02-01

    Full Text Available Based on the idea of alloying welding seams, a series of Zn–xAl filler metals was calculated and designed for joining Mg/Al dissimilar metals by gas tungsten arc (GTA welding. An infrared thermography system was used to measure the temperature of the welding pool during the welding process to investigate the solidification process. It was found that the mechanical properties of the welded joints were improved with the increasing of the Al content in the Zn–xAl filler metals, and when Zn–30Al was used as the filler metal, the ultimate tensile strength could reach a maximum of 120 MPa. The reason for the average tensile strength of the joint increasing was that the weak zone of the joint using Zn–30Al filler metal was generated primarily by α-Al instead of MgZn2. When Zn–40Al was used as the filler metal, a new transition zone, about 20 μm-wide, appeared in the edge of the fusion zone near the Mg base metal. Due to the transition zones consisting of MgZn2- and Al-based solid solution, the mechanical property of the joints was deteriorated.

  14. The effectiveness of ERC advanced life support (ALS) provider courses for the retention of ALS knowledge.

    Science.gov (United States)

    Fischer, Henrik; Strunk, Guido; Neuhold, Stephanie; Kiblböck, Daniel; Trimmel, Helmut; Baubin, Michael; Domanovits, Hans; Maurer, Claudia; Greif, Robert

    2012-02-01

    Out-of-hospital emergency physicians in Austria need mandatory emergency physician training, followed by biennial refresher courses. Currently, both standardized ERC advanced life support (ALS) provider courses and conventional refresher courses are offered. This study aimed to compare the retention of ALS-knowledge of out-of-hospital emergency physicians depending on whether they had or had not participated in an ERC-ALS provider course since 2005. Participants (n=807) from 19 refresher courses for out-of-hospital emergency physicians answered eight multiple-choice questions (MCQ) about ALS based on the 2005 ERC guidelines. The pass score was 75% correct answers. A multivariate logistic regression analyzed differences in passing scores between those who had previously participated in an ERC-ALS provider course and those who had not. Age, gender, regularity of working as an out-of-hospital emergency physician and the self-reported number of real resuscitation efforts within the last 6months were entered as control variables. Out-of-hospital emergency physicians who had previously attended an ERC-ALS provider course had a significantly higher chance of passing the MCQ test (OR=1.60, p=0.015). Younger age (OR=0.95, pERC-ALS provider course since 2005 had a higher retention of ALS knowledge compared to non-ERC-ALS course participants. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  15. Chemical failure modes of AlQ3-based OLEDs: AlQ3 hydrolysis.

    Science.gov (United States)

    Knox, John E; Halls, Mathew D; Hratchian, Hrant P; Schlegel, H Bernhard

    2006-03-28

    Tris(8-hydroxyquinoline)aluminum(III), AlQ3, is used in organic light-emitting diodes (OLEDs) as an electron-transport material and emitting layer. The reaction of AlQ3 with trace H2O has been implicated as a major failure pathway for AlQ3-based OLEDs. Hybrid density functional calculations have been carried out to characterize the hydrolysis of AlQ3. The thermochemical and atomistic details for this important reaction are reported for both the neutral and oxidized AlQ3/AlQ3+ systems. In support of experimental conclusions, the neutral hydrolysis reaction pathway is found to be a thermally activated process, having a classical barrier height of 24.2 kcal mol(-1). First-principles infrared and electronic absorption spectra are compared to further characterize AlQ3 and the hydrolysis pathway product, AlQ2OH. The activation energy for the cationic AlQ3 hydrolysis pathway is found to be 8.5 kcal mol(-1) lower than for the neutral reaction, which is significant since it suggests a role for charge imbalance in promoting chemical failure modes in OLED devices.

  16. 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.

  17. Rupture of Al matrix in U-Mo/Al dispersion fuel by fission induced creep

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Gwan Yoon; Sohn, Dong Seong [UNIST, Daejeon (Korea, Republic of); Kim, Yeon Soo [Argonne National Laboratory, Argonnge (United States); Lee, Kyu Hong [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    This phenomenon was found specifically in the dispersion fuel plate with Si addition in the Al matrix to suppress interaction layer (IL) formation between UMo and Al. It is known that the stresses induced by fission induced swelling in U-Mo fuel particles are relieved by creep deformation of the IL, surrounding the fuel particles, that has a much higher creep rate than the Al matrix. Thus, when IL growth is suppressed, the stress is instead exerted on the Al matrix. The observed rupture in the Al matrix is believed to be caused when the stress exceeded the rupture strength of the Al matrix. In this study, the possibility of creep rupture of the Al matrix between the neighboring U-Mo fuel particles was examined using the ABAQUS finite element analysis (FEA) tool. The predicted rupture time for a plate was much shorter than its irradiation life indicating a rupture during the irradiation. The higher stress leads Al matrix to early creep rupture in this plate for which the Al matrix with lower creep strain rate does not effectively relieve the stress caused by the swelling of the U-Mo fuel particles. For the other plate, no rupture was predicted for the given irradiation condition. The effect of creeping of the continuous phase on the state of stress is significant.

  18. Al Qaeda in the Arabian Peninsula (AQAP): An Al Qaeda Affiliate Case Study

    Science.gov (United States)

    2017-10-01

    Villarosa, Al-Qaeda in Yemen, Carnegie Endowment, July 7, 2009, http://carnegieendowment.org/2009/07/07/Al-Qaeda-in-yemen- event-1372. 53 Brian Whitaker...73 Khaled Fattah, “Yemen’s Insecurity Dilemma,” Yemen Times, February 11, 2014, http:// carnegie -mec.org/2014/02...Johnsen, and Shari Villarosa, “Al-Qaeda in Yemen.” Carnegie Endowment. July 7, 2009. http://carnegieendowment.org/2009/07/07/Al-Qaeda-in- yemen-event

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Growth of CdTe: Al films; Crecimiento de peliculas de CdTe: Al

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez A, M.; Zapata T, M. [CICATA-IPN, 89600 Altamira, Tamaulipas (Mexico); Melendez L, M. [CINVESTAV-IPN, A.P. 14-740, 07000 Mexico D.F. (Mexico); Pena, J.L. [CINVESTAV-IPN, A.P. 73 Cordemex, 97310 Merida, Yucatan (Mexico)

    2006-07-01

    CdTe: AI films were grown by the close space vapor transport technique combined with free evaporation (CSVT-FE). The Aluminum (Al) evaporation was made by two kinds of sources: one made of graphite and the other of tantalum. The films were deposited on glass substrates. The Al source temperature was varied maintaining the CdTe source temperature fixed as well as the substrate temperature. The films were characterized by x-ray energy dispersive analysis (EDAX), x-ray diffraction and optical transmission. The results showed for the films grown with the graphite source for Al evaporation, the Al did not incorporate in the CdTe matrix, at least to the level of EDAX sensitivity; they maintained the same crystal structure and band gap. For the samples grown with the tantalum source, we were able to incorporate the Al. The x-ray diffraction patterns show that the films have a crystal structure that depends on Al concentration. They were cubic up to 2.16 at. % Al concentration; for 19.65 at. % we found a mixed phase; for Al concentration higher than 21 at. % the films were amorphous. For samples with cubic structure it was found that the lattice parameter decreases and the band gap increases with Al concentration. (Author)

  1. 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.

  2. 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.

  3. 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.)

  4. Kerja Perspektif Al-Qur'an

    Directory of Open Access Journals (Sweden)

    Ahmad Munir

    2011-05-01

    Full Text Available The moslem ethics of life is based on movement as ex­pressed in certain terms like al-sharī’ah, al-tarīqah, al-sirāt, al-sabīl and al-manhaj, that make sense of way and teachings to achieve good life. Islam obliges and gives appreciation of the achievements of Mus­lims. The Qur’an uses several terms to refer to such work; ‘charity, kasb, juhd, ibtighâ’, sa ’yu and su ’âl. From this concept, the Qur’an considers work as nob­le, while begging is despicable. Work means thankful to God for the potential He bestows. The Qur’an promotes work not only because it is the way to achieve the wealth, but also because it possesses the its sacred value for the benefit of fulfilling livelihood. Therefore the work should also be done based on ethical values .

  5. Neuropsychoanalyse: Hirntätigkeit als Zeichenprozess

    Directory of Open Access Journals (Sweden)

    Milan Scheidegger

    2014-12-01

    Full Text Available Fassen wir Geist und Natur nicht als Dichotomie sondern im Sinne von Peirce als Kontinuität auf, dann lässt die genauere Betrachtung des Körpers semiotische Leibphänomene als Zeichen einer Sprache erkennen, deren Grammatik es – im Sinne einer «Bioarchäologie» – zu entschlüsseln gilt. Hierfür stellen die Neurowissenschaften mit modernen Visualisierungstechniken geeignete epistemische Hilfsmittel bereit: Sie machen körperliche Vorgänge des Informationsaustausches sichtbar und heben die semiotisch wenig erschlossene Ebene komplexer neuronaler Zeichentransformationen ans Licht. Um eine Integration der physiologischen und psychologischen Perspektive bemüht sich das transdisziplinäre Projekt der «Neuropsychoanalyse». Sie hebt die Relevanz natürlicher Verarbeitungsmechanismen des Körpers für die subjektiv geprägten Zeichentransformationen des mentalen Erlebens hervor und weicht eine semiotisch allzu undurchlässige Grenzziehung zwischen Psycho- und Neurodynamik etwas auf. Die Hirntätigkeit als potenziell erkenntnisleitenden Zeichenprozess zu verstehen, darf aber nicht in einer unreflektierten Bezugnahme auf neuronale Zeichensysteme münden, wenn die Neuropsychoanalyse mehr als nur eine medienwirksame Neurokarikatur psychodynamischer Konzepte erreichen will.

  6. Threshold states in /sup 26/Al revisited

    Energy Technology Data Exchange (ETDEWEB)

    Champagne, A E; McDonald, A B; Wang, T F; Howard, A J; Magnus, P V; Parker, P D

    1986-03-31

    Threshold states in /sup 26/Al have been re-examined using the /sup 27/Al(/sup 3/He,..cap alpha..)/sup 26/Al and /sup 25/Mg(/sup 3/He,d..gamma..)/sup 26/Al reactions in order to resolve apparent ambiguities in some of the previously reported properties of these states. In particular, the s-wave resonance strength reported at E=37 keV is now found to be located at E/sub c.m./=57.54 keV, and the proton width for the 374 keV resonance has been revised to GAMMA/sub p/=0.82 eV. These results have been used to calculate a new resonance strength of ..omega gamma..= 1.6 x 10/sup -13/ eV for the 57.54 keV resonance. As a result, the stellar production rate for /sup 26/Al is increased by a factor approx.=3-38 for temperatures T/sub 9/=0.05-0.1.

  7. Deletion of ALS5, ALS6 or ALS7 increases adhesion of Candida albicans to human vascular endothelial and buccal epithelial cells

    OpenAIRE

    ZHAO, XIAOMIN; OH, SOON-HWAN; HOYER, LOIS L.

    2007-01-01

    C. albicans yeast forms deleted for ALS5, ALS6 or ALS7 are more adherent than a relevant control strain to human vascular endothelial cell monolayers and buccal epithelial cells. In the buccal and vaginal reconstituted human epithelium (RHE) disease models, however, mutant and control strains caused a similar degree of tissue destruction. Deletion of ALS5 or ALS6 significantly slowed growth of the mutant strain; this phenotype was not affected by addition of excess uridine to the culture medi...

  8. MOSQUE ARCHITECTURE AS A SUSTAINABLE BUILDING IN URBAN (Case Study: Al Markas Al Islamic Mosque Makassar

    Directory of Open Access Journals (Sweden)

    Imriyanti Imriyanti

    2014-02-01

    Full Text Available Abstract Mosque Architecture is a part of Islamic architecture. Mosque should be fused with elements of nature because its function as a place to pray to God who created the universe. Al Markas Al Islamic Makassar mosque is used as a center of Islamic aspirations of the people and the government to accommodate all the activities of moslems in Makassar. Through this function, the provision of Al Markas Al Islamic mosque began from the desire of Islamic societies in Makassar, which wants the Islamic center to be equipped with facilities and infrastructure as well as architectural, monumental buildings and structures that can be last for hundreds of years (continuous, blend with the environment, and also can be used by the public. Having regard to the function of a mosque especially at the Al Markas Al Islamic Makassar mosque, then the problem that arise is how the Al Markas Al Islamic mosque can be survived/sustainable  in order  to function  as a place  of worship  and  as a center  of Islam.  This research  is a descriptive qualitative research that is trying to generate data in the form of systematic and accurate picture of the object of study. The sustaiprophetlity  of Al Markas AL Islamic mosque can be known through the concept of Islam  in accordance with the view of Islam as well as the sustaiprophetlity of the buildings that seen in the spatial pattern of the mosque, appearance, natural lighting, natural ventilation, and user behavior of the mosque. Keywords: mosque architecture, sustaiprophetlity, view of Islam     Abstrak Arsitektur masjid merupakan bagian dari arsitektur Islam. Bangunan masjid sebaiknya dapat menyatu dengan unsur alam karena masjid difungsikan sebagai wadah dalam bersujud/sembahyang  kepada Allah SWT yang menciptakan alam semesta ini. Masjid Al Markas Al Islamic Makassar merupakan kompleks kegiatan Islam yang digunakan sebagai pusat aspirasi masyarakat  dan pemerintahan  yang dapat menampung

  9. 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

  10. Core electron binding energy shifts of AlBr3 and Al2Br6 vapor

    International Nuclear Information System (INIS)

    Mueller, Astrid M.; Plenge, Juergen; Leone, Stephen R.; Canton, Sophie E.; Rude, Bruce S.; Bozek, John D.

    2006-01-01

    The Al 2p and Br 3d inner-shell photoelectron spectra of aluminum tribromide monomer and dimer vapor were measured at 90 and 95 eV photon energy, respectively, to determine the core electron binding energies of the atoms in the two molecular species. While AlBr 3 has three identical Br atoms, Al 2 Br 6 exhibits four terminal and two bridging Br atoms. The species are identified by their distinct valence photoelectron spectra. Comparison of the observed Al 2p 1/2 and Al 2p 3/2 electron binding energies of AlBr 3 with those of Al 2 Br 6 shows that there is a chemical shift of (0.15 ± 0.03) eV to lower energy in the dimer. In Al 2 Br 6 , an assignment is proposed in which the Br 3d 3/2 and Br 3d 5/2 binding energies of terminal Br atoms are (1.18 ± 0.03) eV lower than those of bridging Br atoms. This assignment assumes that both types of Br atoms have similar cross-sections for ionization. With this result, the Br 3d 3/2 and Br 3d 5/2 binding energies of Br atoms in AlBr 3 are (0.81 ± 0.03) eV lower than those of bridging Br atoms of the dimer but (0.37 ± 0.03) eV higher than those of terminal Br atoms of the dimer. The obtained chemical shifts are considered in terms of the binding relations and electron density distributions in both molecules. Chemical shifts that are larger than a few hundred millielectron volts, as observed in the Al 2 Br 6 /AlBr 3 system, offer potential to study the dissociation dynamics of the dimer in a femtosecond visible or ultraviolet-pump/XUV-probe experiment

  11. Solute trapping of Ge in Al

    International Nuclear Information System (INIS)

    Smith, P.M.; West, J.A.; Aziz, M.J.

    1992-01-01

    This paper reports on partitioning during rapid solidification of dilute Al-Ge alloys. Implanted thin films of Al have been pulsed-laser melted to obtain solidification at velocities in the range of 0.01 ms to 3.3 m/s, as measured by the transient conductance technique. Previous and subsequent Rutherford Backscattering depth profiling of the Ge solute in the Al alloys has been used to determine the nonequilibrium partition coefficient k. A significant degree of lateral film growth during solidification confines determination of k to the placing of an upper bound of 0.22 on k for solidification velocities in this range. The authors place a lower limit of 10 m/s on the diffusive velocity, which locates the transition from solute partitioning to solute trapping in the Continuous Growth Model

  12. Al- Khwarizmi and axiomatic foundation of algebra

    International Nuclear Information System (INIS)

    Fares, N.

    2015-01-01

    This paper intends to investigate the axiomatic foundations of algebra, as they were presented in the book of algebra of al-Khwarizmi (9 th century), and as they were developed in many subsequent Arabic works. The paper gives also a description of algebra evolution towards a discipline independent ofgeometry and arithmetic: the two disciplines whosemarriage had led to its birth.By an in depth reading of some details in the text of al Khwarizmi , we concluded that this mathematician intended to lay down the axiomatic foundations of that new discipline. His resort to arithmetical and geometrical means was a way of making his theory more accessible. He used them to justify the axioms: those that were not explicitly introduced per se, and those that were remained implicit. The paper also relies on some unedited writingsof al-Khwarizmi's successors, which could shedlight on the ways they used to consolidate the foundations of algebra and improve its methods. (author)

  13. Superbends expand the scope of Berkeley's ALS

    International Nuclear Information System (INIS)

    Robin, David S.; Robinson, Arthur L.; Tamura, Lori S.

    2002-01-01

    While the ALS has turned out to be a world-leader in providing beams of soft X-rays -- indeed, furnishing these beams remains its core mission -- there has nonetheless been a steadily growing demand from synchrotron radiation users for harder X-rays with higher photon energies. The clamor has been strongest from protein crystallographers whose seemingly insatiable appetite for solving structures of biological macromolecules could not be satisfied by the number of crystallography beamlines available worldwide. But how to provide these X-rays in a cost-effective way without disrupting the thriving research programs of the existing ALS users was the problem. Superconducting bend magnets (superbends) provided the answer for the ALS, which adopted a proposal to replace some of the normal combined-function (gradient) magnets in the curved arcs of the storage ring with superconducting dipoles that could generate higher magnetic fields and thus synchrotron light with a higher critical energy

  14. Evaluation of Functional Disability in ALS

    Directory of Open Access Journals (Sweden)

    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.

  15. Grain refinement of Al wrought alloys with newly developed AlTiC master alloys; Kornfeinung von Al-Knetlegierungen mit neu entwickelten AlTiC-Vorlegierungen

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, W. [Vereinigte Aluminium-Werke AG, Bonn (Germany). Forschung und Entwicklung

    2000-10-01

    AlTiC master alloys are a new grain refiner type to produce an equiaxed grain structure of cast extrusion and rolling ingots. These master alloys contain Ti carbides which act as nucleants of the {alpha} solid solution during solidification. The TiC content is lower than the TiB{sub 2} content of the industrial proved AlTiB master alloys. Benefits of the AlTiC master alloys are the low agglomeration tendency of the Ti carbides in the melt and that no Zr poisoning takes place. Despite of the low Ti carbide content the grain refinement performance can be very efficient, if low melt temperatures during casting will be used and as result of this a sufficient constitutional supercooling at the solidification front is achieved. (orig.)

  16. Autologous Stem Cell Transplant for AL Amyloidosis

    Directory of Open Access Journals (Sweden)

    Vivek Roy

    2012-01-01

    Full Text Available AL amyloidosis is caused by clonal plasma cells that produce immunoglobulin light chains which misfold and get deposited as amyloid fibrils. Therapy directed against the plasma cell clone leads to clinical benefit. Melphalan and corticosteroids have been the mainstay of treatment for a number of years and the recent availability of other effective agents (IMiDs and proteasome inhibitors has increased treatment options. Autologous stem cell transplant (ASCT has been used in the treatment of AL amyloidosis for many years. It is associated with high rates of hematologic response and improvement in organ function. However, transplant carries considerable risks. Careful patient selection is important to minimize transplant related morbidity and mortality and ensure optimal patient outcomes. As newer more affective therapies become available the role and timing of ASCT in the overall treatment strategy of AL amyloidosis will need to be continually reassessed.

  17. [Al-Biruni--a universal scientist].

    Science.gov (United States)

    Kujundzić, E; Masić, I

    1999-01-01

    Al-Biruni's was of Persian descent. He was born in Horesmiya and had studied mathematics, history and medicine. Acquiring knowledge from these sciences, he wrote an outstanding work on chronology of several nations and devoted it to Ziyarit ruler Kabus. He made a chronological overview of calendars from many nations, including Persians, Greeks, Egyptians, Jews, Melkitian and Nestorian Christians, Sabeyaans as well as the old Arabs. Data presented in the work, according to the later authors, were taken from very reliable sources. He was contemporary of Ibn-Sina, and thanks to their friendship, they have discussed very much miscellaneous topics. He belonged to the group of scholars, taken by Gaznevian Soultan Mahmud to a long journey to India. Afterwards Al-Biruni wrote and published detailed work "Description of India"--a work on cultural history of India. Due to excellent abilities of Al-Biruni as a philosopher and scholar, there are still significant and reliable notes about buddhistic philosophy, structure of castes and Brahmans' life style. In this Al-Biruni's masterpiece, there are many comparative analysis of Suffism and certain Indian philosophical methods. Al-Biruni's most important work is "Pharmacopoeia"--"Kitab al-saydala", which brilliantly describes all medicaments. This work has been published in many languages. He also wrote few works on astronomy and astrology. In those works he has explained some astrological events through scientific approach in a such peculiar way that nobody has ever explained before. He was also interested in sciences like geology, mineralology, geography, mathematics, psychology and many others.

  18. 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)

    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.

  19. Magnetic Properties of NdAl2

    DEFF Research Database (Denmark)

    Bak, P.

    1974-01-01

    The magnetic properties of NdAl2 are calculated using a Hamiltonian including crystal-field and isotropic exchange interaction terms. A two-dimensional mean-field theory is evaluated to calculate single-crystal magnetization curves. It is shown that the magnetic properties can be understood using...... the crystal-field parameters derived from the magnetic exciton spectrum measured by Houmann et al. by means of inelastic neutron scattering. The combined lambda -Schottky anomaly in the heat capacity is explained. No additional parameters are introduced....

  20. PERFILES PROFESIONALES Y VALORES RELATIVOS AL TRABAJO

    OpenAIRE

    Moreno, José Eduardo; Marcaccio, Antonela

    2014-01-01

    El objetivo del presente trabajo es evaluar la relación existente entre los valores relativos al trabajo y algunos perfiles profesionales (contabilidad y administración, marketing y ventas, y recepción). El instrumento utilizado es la Escala Argentina de Valores Relativos al Trabajo (Moreno & Marcaccio, 2012) que contiene cuatro subescalas de cinco ítems cada una, a saber: Realización Personal, Reconocimiento Social, Altruismo y Aspiraciones Económicas. La muestra incluye a 425 sujetos (40% v...

  1. Trastornos temporomandibulares en adictos al qat

    OpenAIRE

    Orlando Guerra Cobián; Raúl J Pupo Triguero; Humberto Sarracent Pérez; Kirenia M Rabilero Salgado

    2012-01-01

    Introducción: los trastornos temporomandibulares se asocian frecuentemente al hábito de masticar qat, pero se carece de estudios que detallan sus particularidades, por lo que se realiza este trabajo, con los objetivos de determinar la prevalencia de trastornos temporomandibulares en pacientes adictos al qat, identificar los hallazgos clínicos- radiográficos asociados y clasificar los trastornos temporomandibulares presentes en la población estudiada. Métodos: se realizó un estudio prospectivo...

  2. Complementary and Alternative Therapies in ALS

    Science.gov (United States)

    Bedlack, Richard S.; Joyce, Nanette; Carter, Gregory T.; Pagononi, Sabrina; Karam, Chafic

    2015-01-01

    Synopsis Given the severity of their illness and lack of effective disease modifying agents, it is not surprising that most patients with ALS consider trying complementary and alternative therapies. Some of the most commonly considered alternative therapies include special diets, nutritional supplements, cannabis, acupuncture, chelation and energy healing. This chapter reviews these in detail. We also describe 3 models by which physicians may frame discussions about alternative therapies: paternalism, autonomy and shared decision making. Finally, we review a program called ALSUntangled which using shared shared decision making to review alternative therapies for ALS. PMID:26515629

  3. Surface study and thickness control of thin Al2O3 film on Cu-9%Al(111) single crystal

    International Nuclear Information System (INIS)

    Yamauchi, Yasuhiro; Yoshitake, Michiko; Song Weijie

    2004-01-01

    We were successful in growing a uniform flat Al 2 O 3 film on the Cu-9%Al(111) surface using the improved cleaning process, low ion energy and short time sputtering. The growth of ultra-thin film of Al 2 O 3 on Cu-9%Al was investigated using Auger electron spectroscopy (AES) and a scanning electron microscope (SEM). The Al 2 O 3 film whose maximum thickness was about 4.0 nm grew uniformly on the Cu-9%Al surface. The Al and O KLL Auger peaks of Al 2 O 3 film shifted toward low kinetic energy, and the shifts were related to Schottky barrier formation and band bending at the Al 2 O 3 /Cu-9%Al interface. The thickness of Al 2 O 3 film on the Cu-9%Al surface was controlled by the oxygen exposure

  4. Isothermal cross-sections of Sr-Al-Ge and Ba-Al-Ge systems at 673 K

    International Nuclear Information System (INIS)

    Kutsenok, N.L.; Yanson, T.I.

    1987-01-01

    X-ray and microstructural analyses are used to study phase equilibria in Sr-Al-Ge and Ba-Al-Ge systems. Existence of SrAl 2 Ge 2 , Sr(Al, Ge) 2 Ba(Al, Ge) 2 , Sr 3 Al 2 Ge 2 , Ba 3 Al 2 Ge 2 ternary compounds is confirmed, a new BaGe 4 binary compound and also new ternary compounds of approximate composition Sr 57 Al 30 Ge 13 and Ba 20 Al 40 Ge 40 , which crystal structure is unknown, are detected. Aluminium solubility in SrAl 4 and BaAl 4 binary compounds (0.05 atomic fraction) is determined. Ba(Al, Ge) 2 compound homogeneity region is defined more exactly (aluminium content varies from 0.27 to 0.51 at. fractions)

  5. A study on preparation and hydriding of β-Mg2Al3 and γ-Mg17Al12

    International Nuclear Information System (INIS)

    Hadi Suwarno

    2009-01-01

    The mechanism of the synthetic formation of β-Mg 2 Al 3 and γ-Mg 17 Al 12 has been studied. Mechanical alloying of Mg and Al powders with the atomic ratio of Mg:Al = 2:3 in toluene solution yields β-Mg 2 Al 3 compound after milling for 30 h. The γ-Mg 17 Al 12 can be formed by heating the β-Mg 2 Al 3 at 430°C under high vacuum. The measured hydrogen capacities of β-Mg 2 Al 3 and γ-Mg 17 Al 12 as hydride at 300°C are 3.2 and 4.9 wt%, respectively. Microstructure of the Mg-Al specimen shows that on hydriding at 300°C the polygonal shape of the γ-Mg 17 Al 12 changes into irregular shapes which are composed of γ-MgH 2 and Al. (author)

  6. Computer aided cooling curve analysis for Al-5Si and Al-11Si alloys

    African Journals Online (AJOL)

    user

    fine fibrous form (Hess and Blackmun, 1975; Dahle et al., 2005). ..... grain structure in the casting (Apelian et al., 1984), which in turn are supported in the present work by a decreased ..... Liao H., Zhang M., Wu Q., Wang H. and Sun G., 2007.

  7. Preparation, deformation, and failure of functional Al-Sn and Al-Sn-Pb nanocrystalline alloys

    Science.gov (United States)

    Noskova, N. I.; Vil'Danova, N. F.; Filippov, Yu. I.; Churbaev, R. V.; Pereturina, I. A.; Korshunov, L. G.; Korznikov, A. V.

    2006-12-01

    Changes in the structure, hardness, mechanical properties, and friction coefficient of Al-30% Sn, Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb (wt %) alloys subjected to severe plastic deformation by equal-channel angular pressing (with a force of 40 tonne) and by shear at a pressure of 5 GPa have been studied. The transition into the nanocrystalline state was shown to occur at different degrees of plastic deformation. The hardness exhibits nonmonotonic variations, namely, first it increases and subsequently decreases. The friction coefficient of the Al-30% Sn, Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb alloys quenched from the melt was found to be 0.33; the friction coefficients of these alloys in the submicrocrystalline state (after equal-channel angular pressing) equal 0.24, 0.32, and 0.35, respectively. The effect of disintegration into nano-sized powders was found to occur in the Al-15% Sn-25% Pb, and Al-5% Sn-35% Pb alloys after severe plastic deformation to ɛ = 6.4 and subsequent short-time holding.

  8. Sintering Behavior of CNT Reinforced Al6061 and Al2124 Nanocomposites

    Directory of Open Access Journals (Sweden)

    Nouari Saheb

    2014-01-01

    Full Text Available Ball milling and spark plasma sintering were successfully used to produce carbon nanotube reinforced Al6061 and Al2124 nanocomposites which have potential applications in the fields of aerospace, automotive, electronics, and high precision instrumentation. Al2124 and Al6061 nanocomposite powders containing 0.5 to 2 wt.% CNTs prepared through sonication and wet ball milling were spark plasma sintered at 400, 450, and 500°C for 20 minutes under a pressure of 35 MPa. CNTs were better dispersed, and less agglomerated and had good adhesion to the matrix in composites containing 1 wt.% CNTs. The increase of CNT content to 2 wt.% led to the formation of CNT clusters which resulted in less uniform and homogenous composite powders. Almost full densification of Al6061 reinforced with CNTs was achieved at 500°C. Also, CNTs reinforced Al2124 nanocomposites reached very high densities at 500°C. Composites reinforced with 1 wt.% CNTs displayed better densification compared to composites containing 2 wt.% CNTs. The increase of CNTs content from 0.5 to 1 wt.% increased the hardness of the Al6061 and Al2124 alloys to maximum values. Further increase of CNTs content to 2 wt.% decreased the hardness to values lower than that of the monolithic alloys.

  9. Al-muammar et al., Afr J Tradit Complement Altern Med. (2016) 13(1 ...

    African Journals Online (AJOL)

    PROF ADEWUNMI

    Al-muammar et al., Afr J Tradit Complement Altern Med. (2016) 13(1):17- .... Feed and water were provided ad libitum for one week before the start of experiment for adaptation. The basal .... The mean value of feed intake (g/day/rat) for all treated groups was slightly reduced as compared to the negative control group. On the.

  10. Mechanical properties and deformation behavior of Al/Al7075, two-phase material

    International Nuclear Information System (INIS)

    Sherafat, Z.; Paydar, M.H.; Ebrahimi, R.; Sohrabi, S.

    2010-01-01

    In the present study, mechanical properties and deformation behavior of Al/Al7075, two-phase material were investigated. The two-phase materials were fabricated by mixing commercially pure Al powder with Al7075 chips and consolidating the mixture through hot extrusion process at 500 o C. Mechanical properties and deformation behavior of the fabricated samples were evaluated using tensile and compression tests. A scanning electron microscope was used to study the fracture surface of the samples including different amount of Al powder, after they were fractured in tensile test. The results of the tensile and compression tests showed that with decreasing the amount of Al powder, the strength increases and ductility decreases. Calculation of work hardening exponent (n) indicated that deformation behavior does not follow a regular trend. In a way that the n value was approved to be variable and a strong function of strain and Al powder wt% of the sample. The results of the fractography studies indicate that the type of fracture happened changes from completely ductile to nearly brittle by decreasing the wt% of Al powder from 90% to 40%.

  11. Surface modified Al2O3 in fluorinated polyimide/Al2O3 ...

    Indian Academy of Sciences (India)

    guest group into a host structure without a major struc- tural modification of the ... on nano-structure size (Li et al 2009). Among ... naocomposite by the decrease of interfacial areas between ... pling agent which usually has a long alkyl tail shows a good ... the mechanical and thermal properties of polymers (Li et al. 2010).

  12. The ALS-FTD-Q: A new screening tool for behavioral disturbances in ALS

    NARCIS (Netherlands)

    Raaphorst, J.; Beeldman, E.; Schmand, B.; Berkhout, J.; Linssen, W.H.J.P.; Van den Berg, L.H.; Pijnenburg, Y.A.L.; Grupstra, H.F.; Weikamp, J.G.; Schelhaas, H.J.; Papma, J.M.; van Swieten, J.C.; de Visser, M.; de Haan, R.J.

    2012-01-01

    Objective: The assessment of behavioral disturbances in amyotrophic lateral sclerosis (ALS) is important because of the overlap with the behavioral variant of frontotemporal dementia (ALS-bvFTD). Motor symptoms and dysarthria are not taken into account in currently used behavioral questionnaires. We

  13. The ALS-FTD-Q: a new screening tool for behavioural disturbances in ALS

    NARCIS (Netherlands)

    Raaphorst, J.; Beeldman, E.; Schmand, B.; Berkhout, J.; Linssen, W.H.J.P.; van den Berg, L.H.; Pijnenburg, Y.A.; Grupstra, H.F.; Weikamp, J.G.; Schelhaas, H.J.; Papma, J.M.; van Swieten, J.C.; de Visser, M.; de Haan, R.J.

    2012-01-01

    Objective: The assessment of behavioral disturbances in amyotrophic lateral sclerosis (ALS) is important because of the overlap with the behavioral variant of frontotemporal dementia (ALS-bvFTD). Motor symptoms and dysarthria are not taken into account in currently used behavioral questionnaires. We

  14. The ALS-FTD-Q A new screening tool for behavioral disturbances in ALS

    NARCIS (Netherlands)

    Raaphorst, Joost; Beeldman, Emma; Schmand, Ben; Berkhout, Joris; Linssen, Wim H. J. P.; van den Berg, Leonard H.; Pijnenburg, Yolande A.; Grupstra, Hepke F.; Weikamp, Janneke G.; Schelhaas, H. Jurgen; Papma, Janne M.; van Swieten, John C.; de Visser, Marianne; de Haan, Rob J.

    2012-01-01

    Objective: The assessment of behavioral disturbances in amyotrophic lateral sclerosis (ALS) is important because of the overlap with the behavioral variant of frontotemporal dementia (ALS-bvFTD). Motor symptoms and dysarthria are not taken into account in currently used behavioral questionnaires. We

  15. The ALS-FTD-Q: a new screening tool for behavioral disturbances in ALS

    NARCIS (Netherlands)

    Raaphorst, J.; Beeldman, E.; Schmand, B.A.; Berkhout, J.; Linssen, W.H.J.P.; Berg, L.H. van den; Pijnenburg, Y.A.; Grupstra, H.F.; Weikamp, J.G.; Schelhaas, H.J.; Papma, J.M.; van Swieten, J.C.; Visser, M. de; Haan, R.J. de

    2012-01-01

    OBJECTIVE: The assessment of behavioral disturbances in amyotrophic lateral sclerosis (ALS) is important because of the overlap with the behavioral variant of frontotemporal dementia (ALS-bvFTD). Motor symptoms and dysarthria are not taken into account in currently used behavioral questionnaires. We

  16. InAlGaAs/AlGaAs quantum wells: line widths, transition energies and segregation

    DEFF Research Database (Denmark)

    Jensen, Jacob Riis; Hvam, Jørn Märcher; Langbein, Wolfgang

    2000-01-01

    We investigate the optical properties of InAlCaAs/AlGaAs quantum wells pseudomorphically grown on GaAs using molecular beam epitaxy (MBE). The transition energies, measured with photoluminescence (PL), are modelled solving the Schrodinger equation, and taking into account segregation in the group...

  17. Direct observations of grain boundary phenomena during indentation of Al and Al-Mg thin films

    NARCIS (Netherlands)

    Soer, WA; De Hosson, JTM; Minor, AM; Stach, EA; Morris, Joan K.; Corcoran, SG; Joo, YC; Moody, NR; Suo, Z

    2004-01-01

    The deformation behaviour of Al and Al-Mg thin films has been studied with the unique experimental approach of in-situ nanoindentation in a transmission electron microscope. This paper concentrates on the role of solute Mg additions in the transfer of plasticity across grain boundaries. The

  18. Burden of rare variants in ALS genes influences survival in familial and sporadic ALS.

    Science.gov (United States)

    Pang, Shirley Yin-Yu; Hsu, Jacob Shujui; Teo, Kay-Cheong; Li, Yan; Kung, Michelle H W; Cheah, Kathryn S E; Chan, Danny; Cheung, Kenneth M C; Li, Miaoxin; Sham, Pak-Chung; Ho, Shu-Leong

    2017-10-01

    Genetic variants are implicated in the development of amyotrophic lateral sclerosis (ALS), but it is unclear whether the burden of rare variants in ALS genes has an effect on survival. We performed whole genome sequencing on 8 familial ALS (FALS) patients with superoxide dismutase 1 (SOD1) mutation and whole exome sequencing on 46 sporadic ALS (SALS) patients living in Hong Kong and found that 67% had at least 1 rare variant in the exons of 40 ALS genes; 22% had 2 or more. Patients with 2 or more rare variants had lower probability of survival than patients with 0 or 1 variant (p = 0.001). After adjusting for other factors, each additional rare variant increased the risk of respiratory failure or death by 60% (p = 0.0098). The presence of the rare variant was associated with the risk of ALS (Odds ratio 1.91, 95% confidence interval 1.03-3.61, p = 0.03), and ALS patients had higher rare variant burden than controls (MB, p = 0.004). Our findings support an oligogenic basis with the burden of rare variants affecting the development and survival of ALS. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  19. First-principles study of L10 Ti-Al and V-Al alloys

    International Nuclear Information System (INIS)

    Chubb, S.R.; Papaconstantopoulos, D.A.; Klein, B.M.

    1988-01-01

    As a first step towards understanding the reduced embrittlement of L1 0 Ti-Al alloys which accompanies the introduction of small concentrations of V, we have determined from first principles, using full-potential linearized--augmented-plane-wave calculations, the equilibrium values of the structural parameters and the associated electronic structure for the stoichiometric (L1 0 ) Ti-Al (tetragonal) compound. Our calculated values of c/a and a are in good agreement with experiment. Using the same method of calculation, we have also studied the electronic structure associated with the (hypothetical) L1 0 V-Al alloy that would form when V is substituted for Ti. We find that (1) the electronic structures of these V-Al alloys are relatively insensitive to variations of c/a and a; (2) near the Ti-Al equilibrium geometry, the electronic structures of the V-Al and Ti-Al alloys are very similar; and (3) that a rigid-band model involving substitution of V for Ti can be used to gain a qualitative understanding of the reduction in c/a which accompanies the introduction of small concentrations of V. We relate the reduction in c/a to important changes in the bonding that accompany the occupation of bands immediately above the Fermi level of the stoichiometric Ti-Al compound

  20. NEK1 genetic variability in a Belgian cohort of ALS and ALS-FTD patients.

    Science.gov (United States)

    Nguyen, Hung Phuoc; Van Mossevelde, Sara; Dillen, Lubina; De Bleecker, Jan L; Moisse, Matthieu; Van Damme, Philip; Van Broeckhoven, Christine; van der Zee, Julie

    2018-01-01

    We evaluated the genetic impact of the amyotrophic lateral sclerosis (ALS) risk gene never in mitosis gene a-related kinase 1 (NEK1) in a Belgian cohort of 278 patients with ALS (n = 245) or ALS with frontotemporal dementia (ALS-FTD, n = 33) and 609 control individuals. We identified 2 ALS patients carrying a loss-of-function (LOF) mutation, p.Leu854Tyrfs*2 and p.Tyr871Valfs*17, that was absent in the control group. A third LOF variant p.Ser1036* was present in 2 sibs with familial ALS but also in an unrelated control person. Missense variants were common in both patients (3.6%) and controls (3.0%). The missense variant, p.Arg261His, which was previously associated with ALS risk, was detected with a minor allele frequency of 0.90% in patients compared to 0.33% in controls. Taken together, NEK1 LOF variants accounted for 1.1% of patients, although interpretation of pathogenicity and penetrance is complicated by the observation of occasional LOF variants in unaffected individuals (0.16%). Furthermore, enrichment of additional ALS gene mutations was observed in NEK1 carriers, suggestive of a "second hit" model were NEK1 variants may modify disease presentation of driving mutations. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  1. The Genyornis Egg: Response to Miller et al.'s commentary on Grellet-Tinner et al., 2016

    Science.gov (United States)

    Grellet-Tinner, Gerald; Spooner, Nigel A.; Handley, Warren D.; Worthy, Trevor H.

    2017-04-01

    Williams (1981) and Williams and Rich (1991) attributed Australian Quaternary fossil eggshell that differed from that of emu Dromaius novaehollandiae to the extinct bird Genyornis newtoni without any osteological or embryonic support. Such association by proximity or abundance mirrors the case of the mistaken association of oviraptor eggs to Protoceratops in the 1920's by Andrews (Grellet-Tinner and Makovicky, 2006). No other candidate species was considered, and this attribution has been unchallenged and followed by everyone thereafter. Much research has been done on this Australian eggshell, with one result being that the extinction of the parent of this eggshell is the most well documented for a taxon in Australia (e.g., Miller et al., 1999, 2005). Grellet-Tinner et al. (2016) raised several problems with the identity of the eggshell Williams (1981) attributed to Genyornis newtoni and suggested that extinct megapodes of the genus Progura were the more likely layer of this eggshell type, therein referred to as ;putative Genyornis oological material; (PGOM). Miller et al. (2017) challenged our hypothesis stating that ;Based on the dimensions of the reconstructed Spooner Egg,Grellet-Tinner et al. (2016)argue that PGOM is too small for a bird with the body mass estimated for Genyornis (168-275 kg) … …[and] …. None of the additional PGOM observations reported byGrellet-Tinner et al. (2016)are inconsistent with a Genyornis parent;. Here we take the opportunity to respond to their critique, the basis of which resolves into a few points, which we address in turn.

  2. Fluctuations of charge variance and interaction time for dissipative processes in 27 Al + 27 Al collision

    International Nuclear Information System (INIS)

    Berceanu, I.; Andronic, A.; Duma, M.

    1999-01-01

    The systematic studies of dissipative processes in light systems were completed with experiments dedicated to the measurement of the excitation functions in 19 F + 27 Al and 27 Al + 27 Al systems in order to obtain deeper insight on DNS configuration and its time evolution. The excitation function for 19 F + 27 Al system evidenced fluctuations larger than the statistical errors. Large Z and angular cross correlation coefficients supported their non-statistical nature. The energy dependence of second order observables, namely the second moment of the charge distribution and the product ω·τ (ω - the angular velocity of the DNS and τ its mean lifetime) extracted from the angular distributions were studied for 19 F + 27 Al case. In this contribution we are reporting the preliminary results of similar studies performed for 27 Al + 27 Al case. The variance of the charge distribution were obtained fitting the experimental charge distribution with a Gaussian centered on Z = 13 and the product ω·τ was extracted from the angular distributions. The results for 19 F + 27 Al case are confirmed by a preliminary analysis of the data for 27 Al + 27 Al system. The charge variance and ω·τ excitation functions for Z = 11 fragment are represented together with the excitation function of the cross section. One has to mention that the data for 27 Al + 27 Al system were not corrected for particle evaporation processes. The effect of the evaporation corrections on the excitation function was studied using a Monte Carlo simulation. The α particle evaporation was also included and the evaluation of the particle separation energies was made using experimental masses of the fragments. The excitation functions for 27 Al + 27 Al system for primary and secondary fragments were simulated. No structure due to particle evaporation was observed. The correlated fluctuations in σ Z and ω·τ excitation functions support a stochastic exchange of nucleons as the main mechanism for

  3. 26Mg(p,n)26Al and 23Na(α,n)26Al reactions

    International Nuclear Information System (INIS)

    Skelton, R.T.

    1985-01-01

    Cross sections for the 26 Mg(p,n) 26 Al reaction were measured from threshold at 4.988 MeV to 5.820 MeV. Cross sections for the 23 Na(α,n) 26 Al reaction were measured from threshold at 3.483 MeV to 4.597 MeV. In each case, separate measurements were to the ground state and to the first and second excited states of 26 Al. Cross sections for the inverse reactions were calculated and reaction rate factors relating to the destruction of 26 Al in a supernova environment were determined. Astrophysical implications relating to the observation of live and extinct 26 Al are discussed. Excitation functions for several additional exit channels for the 26 Mg + rho and 23 Na + α reactions are reported

  4. Grain refinement of 7075Al alloy microstructures by inoculation with Al-Ti-B master alloy

    Science.gov (United States)

    Hotea, V.; Juhasz, J.; Cadar, F.

    2017-05-01

    This paper aims to bring some clarification on grain refinement and modification of high strength alloys used in aerospace technique. In this work it was taken into account 7075 Al alloy, and the melt treatment was carried out by placing in the form of master alloy wire ternary AlTiB the casting trough at 730°C. The morphology of the resulting microstructures was characterized by optical microscopy. Micrographs unfinished and finished with pre-alloy containing ternary Al5Ti1B evidence fine crystals, crystal containing no columnar structure and highlights the size of the dendrites, and intermetallic phases occurring at grain boundaries in Al-Zn-Mg-Cu alloy. It has been found that these intermetallic compounds are MgZn2 type. AlTiB master alloys finishing ensures a fine eutectic structure, which determines the properties of hardware and improving the mechanical properties of aluminum alloys used in aeronautical engineering.

  5. 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

  6. Production of 26Al by spallation of Fe, Si, Al nuclei

    International Nuclear Information System (INIS)

    Paillard, P.

    1977-01-01

    Cross sections for 7 Be, 10 Be and 26 Al formation in Al, Si and Fe targets bombarded with 0.6 and 24GeV protons have been measured by using highly selective chemical separation and low level background counters. Results for 26 Al at 0.6GeV are in mb: 17.9 + or - 2.7 in Al, 12.5 + or - 2.5 in Si and 0.45 + or - 0.14 in Fe; at 24GeV 2.6 + or - 0.5mb in Fe. Results for 10 Be are not valid on account of experimental difficulties. It is deduced from these values of aluminium in cosmic ray propagation that 26 Al is not yet cosmic ray chronometer [fr

  7. Different magnetic behaviour of the Kondo compounds Al3Ce and Al11Ce3

    International Nuclear Information System (INIS)

    Benoit, A.; Flouquet, J.; Palleau, J.; Buevoz, J.L.

    1979-08-01

    Neutron diffraction experiments on the Al 3 Ce and Al 11 Ce 3 compounds have been performed on the multidetector of the I.L.L. high flux reactor. No magnetic structure has been detected on the Al 3 Ce compound down to 20 mK. This confirms the non magnetic ground state of Al 3 Ce. For Al 11 Ce 3 , two magnetic structures have been observed: a ferromagnetic one at 4.2 K and an antiferromagnetic one at 2 K. The antiferromagnetic structure, which corresponds to a propagation vector (0,0,1/3), implies a strong reduction of the magnetic moment of determined sites; this reflects the Kondo character of the compounds

  8. Phase constituents and microstructure of laser cladding Al2O3/Ti3Al reinforced ceramic layer on titanium alloy

    International Nuclear Information System (INIS)

    Li Jianing; Chen Chuanzhong; Lin Zhaoqing; Squartini, Tiziano

    2011-01-01

    Research highlights: → In this study, Fe 3 Al has been chosen as cladding powder due to its excellent properties of wear resistance and high strength, etc. → Laser cladding of Fe 3 Al + TiB 2 /Al 2 O 3 pre-placed alloy powder on Ti-6Al-4V alloy substrate can form the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer, which can increase wear resistance of substrate. → In cladding process, Al 2 O 3 can react with TiB 2 leading to formation of Ti 3 Al and B. → This principle can be used to improve the Fe 3 Al + TiB 2 laser-cladded coating. - Abstract: Laser cladding of the Fe 3 Al + TiB 2 /Al 2 O 3 pre-placed alloy powder on Ti-6Al-4V alloy can form the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer, which can greatly increase wear resistance of titanium alloy. In this study, the Ti 3 Al/Fe 3 Al + TiB 2 /Al 2 O 3 ceramic layer has been researched by means of electron probe, X-ray diffraction, scanning electron microscope and micro-analyzer. In cladding process, Al 2 O 3 can react with TiB 2 leading to formation of amount of Ti 3 Al and B. This principle can be used to improve the Fe 3 Al + TiB 2 laser cladded coating, it was found that with addition of Al 2 O 3 , the microstructure performance and micro-hardness of the coating was obviously improved due to the action of the Al-Ti-B system and hard phases.

  9. Estudo do desgaste abrasivo das resinas compostas disponíveis no mercado brasileiro

    Directory of Open Access Journals (Sweden)

    Eduardo Carlos Bianchi

    2003-06-01

    Full Text Available This work presents a proposal to assess the abrasive wear of composite resins available in the national market, which are materials largely used in dental clinics for functional and aesthetic tooth restorations. This was achieved by utilizing an experimental set-up on which a dynamic disc covered with proper porcelain (representing hardness close to the human teeth wears a static disc covered with the resin tested under a constant and pre-determined load. Thus, by means of this set-up and keeping a behavioral status needed to the calculus for all tests, the aggressiveness (referred as to letter k for all tests was analyzed. Due to the fact that resin characteristic revels how weary the material has become to the abrasion process with other harder material, the strength to wear for such resins was observed. Therefore, a real classification for these materials with their strength to the abrasion wear was made, which is a very important factor in the influence on their lifetime in dental restorations. The classification in descending order for those resins is presented as following: HELIOMOLAR RO, DURAFILL, FILTEK A110, HELIO FILL, POINT 4, FLOW IT; NATURAL FLOW, SUPRAFILL, FILTEK P60, FILTEK Z250, TETRIC FLOW, REVOLUTION, PRODIGY, TETRIC CERAM, HERCULITE, FILLMAGIC, TPH, CHARISMA, Z100.

  10. Produtivismo e precariedade subjetiva na universidade pública: o desgaste mental dos docentes

    OpenAIRE

    Bernardo, Marcia Hespanhol

    2014-01-01

    Nos últimos anos, tem-se observado cada vez mais características típicas de mercado presentes na universidade pública. No Brasil, o aspecto com maior destaque nas publicações é o "produtivismo acadêmico", que tem como mote a ênfase na quantidade de produções bibliográficas. Neste artigo, busca-se discutir as características desse modelo, partindo-se do pressuposto que ele conduza a uma situação de precariedade subjetiva para os docentes. Para tal, apresenta-se o resultado de uma pesquisa qual...

  11. 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.

  12. Microstructural defects modeling in the Al-Mo system

    International Nuclear Information System (INIS)

    Pascuet, Maria I.; Fernandez, Julian R.; Monti, Ana M.

    2006-01-01

    In this work we have utilized computer simulation techniques to study microstructural defects, such as point defects and interfaces, in the Al-Mo alloy. Such alloy is taken as a model to study the Al(fcc)/U-Mo(bcc) interface. The EAM interatomic potential used has been fitted to the formation energy and lattice constant of the AlMo 3 intermetallic. Formation of vacancies for both components Al and Mo and anti-sites, Al Mo and Mo Al , as well as vacancy migration was studied in this structure. We found that the lowest energy defect complex that preserves stoichiometry is the antisite pair Al Mo +Mo Al , in correspondence with other intermetallics of the same structure. Our results also suggest that the structure of the Al(fcc)/Mo(bcc) interface is unstable, while that of the Al(fcc)/Al 5 Mo interface is stable, as observed experimentally. (author) [es

  13. The constitution of alloys in the Al-rich corner of the Al-Si-Sm ternary system

    International Nuclear Information System (INIS)

    Markoli, B.; Spaic, S.; Zupanic, F.

    2001-01-01

    The constitution of alloys and the liquidus surface in the Al-rich corner of the Al-Si-Sm ternary system were determined by the examination of controlled heated and cooled specimens, as well as heat-treated specimens by means of optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential thermal analysis and X-ray diffraction. The Al-rich corner of the Al-Si-Sm ternary system comprises five regions of primary crystallisation (α Al , β Si , Al 3 Sm, Al 2 Si 2 Sm and AlSiSm) with following characteristic invariant reaction sequences: ternary eutectic reaction L → α Al + β Si + Al 2 Si 2 Sm, and two liquidus transition reactions, i. e., L + Al 3 Sm → α Al + AlSiSm, and L + AlSiSm → α Al + Al 2 Si 2 Sm. Along with the position of ternary eutectic and both interstitial points in the Al-rich corner of the Al-Si-Sm ternary system, the temperatures for each reaction were determined. (orig.)

  14. The constitution of alloys in the Al-rich corner of the Al-Si-Sm ternary system

    Energy Technology Data Exchange (ETDEWEB)

    Markoli, B.; Spaic, S. [Ljubljana Univ. (Slovenia). Faculty of Natural Science and Engineering; Zupanic, F. [Maribor Univ. (Slovenia). Faculty of Mechanical Engineering

    2001-09-01

    The constitution of alloys and the liquidus surface in the Al-rich corner of the Al-Si-Sm ternary system were determined by the examination of controlled heated and cooled specimens, as well as heat-treated specimens by means of optical and scanning electron microscopy, energy-dispersive X-ray spectroscopy, differential thermal analysis and X-ray diffraction. The Al-rich corner of the Al-Si-Sm ternary system comprises five regions of primary crystallisation ({alpha}{sub Al}, {beta}{sub Si}, Al{sub 3}Sm, Al{sub 2}Si{sub 2}Sm and AlSiSm) with following characteristic invariant reaction sequences: ternary eutectic reaction L {yields} {alpha}{sub Al} + {beta}{sub Si} + Al{sub 2}Si{sub 2}Sm, and two liquidus transition reactions, i. e., L + Al{sub 3}Sm {yields} {alpha}{sub Al} + AlSiSm, and L + AlSiSm {yields} {alpha}{sub Al} + Al{sub 2}Si{sub 2}Sm. Along with the position of ternary eutectic and both interstitial points in the Al-rich corner of the Al-Si-Sm ternary system, the temperatures for each reaction were determined. (orig.)

  15. Electronic Structures and Bonding Properties of Ti2AlC and Ti3AlC2

    Institute of Scientific and Technical Information of China (English)

    MIN Xinmin; REN Yi

    2007-01-01

    The relation among electronic structure, chemical bond and property of Ti2AlC, Ti3AlC2 and doping Si into Ti2AlC was studied by density function and the discrete variation (DFT-DVM) method. After adding Si into Ti2AlC, the interaction between Si and Ti is weaker than that between Al and Ti, and the strengths of ionic and covalent bonds decrease both. The ionic and covalent bonds in Ti3AlC2, especially in Ti-Al, are stronger than those in Ti2AlC. Therefore, in synthesis of Ti2AlC, the addition of Si enhances the Ti3AlC2 content instead of Ti2AlC. The density of state (DOS) shows that there is mixed conductor characteristic in Ti2AlC and Ti3AlC2. The DOS of Ti3AlC2 is much like that of Ti2AlC. Ti2SixAl1-x C has more obvious tendency to form a semiconductor than Ti2AlC, which is seen from the obvious difference of partial DOS between Si and Al3p.

  16. NMR evidence for Co-Al-Co molecular groups trapped in cages of Co4Al13

    International Nuclear Information System (INIS)

    Jeglic, P.; Heggen, M.; Feuerbacher, M.; Bauer, B.; Gille, P.; Haarmann, F.

    2009-01-01

    We present the results of 27 Al nuclear magnetic resonance (NMR) experiments on the phase Co 4 Al 13 . These results are compared to a recent structure model [1], which demonstrates a unique bonding for Al atoms in the Co-Al-Co molecular groups. In our measurement, two 27 Al signals were identified. The first one originates from Al atoms forming cages. The second signal corresponds to Al sites with exceptionally large almost axially symmetric quadrupole coupling. This finding is in perfect agreement with isolated Co-Al-Co molecular groups in accordance to Ref. [1].

  17. Control al doping Compromiso de Colombia

    Directory of Open Access Journals (Sweden)

    Claudia Prieto

    2015-06-01

    Full Text Available Este documento da a conocer la importante noticia de la aprobación, por parte del Comité Olímpico Internacional (COl, de un laboratorio colombiano, para el control al doping, a la vez que aprovecha la oportunidad para ampliar alguna información sobre este tema.

  18. EXPERIMENT AL AND THEORETICAL STUDY OF PRECAST ...

    African Journals Online (AJOL)

    EXPERIMENT AL AND THEORETICAL STUDY OF PRECAST BEAM-SLAB. CONSTRUCTION. Girma Zerayohannes and Adil Zekaria. Department of Civil Engineering. Addis Ababa University. ABSTRACT. The use of partially precast beam elements ivith shear connectors in slab construction relieves the requirement of ...

  19. 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.

  20. Management of respiratory symptoms in ALS.

    LENUS (Irish Health Repository)

    Hardiman, Orla

    2012-02-01

    Respiratory insufficiency is a frequent feature of ALS and is present in almost all cases at some stage of the illness. It is the commonest cause of death in ALS. FVC is used as important endpoint in many clinical trials, and in decision-making events for patients with ALS, although there are limitations to its predictive utility. There are multiple causes of respiratory muscle failure, all of which act to produce a progressive decline in pulmonary function. Diaphragmatic fatigue and weakness, coupled with respiratory muscle weakness, lead to reduced lung compliance and atelectasis. Increased secretions increase the risk of aspiration pneumonia, which further compromises respiratory function. Bulbar dysfunction can lead to nutritional deficiency, which in turn increases the fatigue of respiratory muscles. Early recognition of respiratory decline and symptomatic intervention, including non-invasive ventilation can significantly enhance both quality of life and life expectancy in ALS. Patients with respiratory failure should be advised to consider an advance directive to avoid emergency mechanical ventilation.

  1. Management of respiratory symptoms in ALS.

    LENUS (Irish Health Repository)

    Hardiman, Orla

    2011-03-01

    Respiratory insufficiency is a frequent feature of ALS and is present in almost all cases at some stage of the illness. It is the commonest cause of death in ALS. FVC is used as important endpoint in many clinical trials, and in decision-making events for patients with ALS, although there are limitations to its predictive utility. There are multiple causes of respiratory muscle failure, all of which act to produce a progressive decline in pulmonary function. Diaphragmatic fatigue and weakness, coupled with respiratory muscle weakness, lead to reduced lung compliance and atelectasis. Increased secretions increase the risk of aspiration pneumonia, which further compromises respiratory function. Bulbar dysfunction can lead to nutritional deficiency, which in turn increases the fatigue of respiratory muscles. Early recognition of respiratory decline and symptomatic intervention, including non-invasive ventilation can significantly enhance both quality of life and life expectancy in ALS. Patients with respiratory failure should be advised to consider an advance directive to avoid emergency mechanical ventilation.

  2. CALCULUL CINETOSTATIC AL MECANISMELOR PLANETARE CILINDRICE

    Directory of Open Access Journals (Sweden)

    Păun ANTONESCU

    2012-05-01

    Full Text Available În lucrare se prezintă o metodă analitică pentru calculul cinetostatic al mecanismului planetarmonomobil cu două roţi dinţate centrale. Se consideră mai întâi cazul general al schemelor cinematice cu douăroţi dinţate solidare tip satelit, în două variante practice (multiplicator şi reductor de turaţie. Este menţionatcazul particular al mecanismelor planetare cu o singură roată satelit cu angrenare dublă (exterioară şiinterioară. Pe baza modelului de analiză cinetostatică a mecanismului planetar monomobil cu două roţi dinţatecentrale, în finalul lucrării se abordează o problemă practică de calcul cinetostatic al unui mecanism planetarcilindric simplu folosit la capul de frezat pentru prelucrarea roţilor dinţate cilindrice cu dinţi curbi înhipocicloidă.

  3. Niedermolekulare Verbindungen aus Spinnen als chemische Sensoren

    DEFF Research Database (Denmark)

    Olsen, Christian Adam; Kristensen, Anders S.; Strømgaard, Kristian

    2011-01-01

    sie als Leitstrukturen für die Entwicklung, Synthese und biologische Untersuchung synthetischer Analoga verwendet. Weit weniger erforscht sind hingegen Verbindungen, die der Kommunikation von Spinnen dienen. Vor kurzem wurden jedoch auf dem Gebiet der Pheromone und Allomone aus Spinnen neue...

  4. Olawumi et al., Afr. J. Infect. Dis.

    African Journals Online (AJOL)

    AJTCAM

    2011-08-31

    Aug 31, 2011 ... Consequently pathogen reduction using riboflavin and UV light, which is a method by which infectious pathogens, including plasmodium in blood for transfusion are inactivated by adding riboflavin and irradiating with UV light , is another effort in transfusion medicine to ensure blood safety. (Hardwick et al,.

  5. Studentopinie als onderdeel van Cursuskwaliteit : Quickscan

    NARCIS (Netherlands)

    Elzinga, Hanny; Groenewoud, Jan; Ike, Paul; Loth, Betram; Reitsma, Sieuwke; Schotanus, Janke; Schuurman, Mieke; Steur, Jessica

    2015-01-01

    In het kader van dit onderzoek is een quickscan (15 vragen) opgesteld met als doel die informatie te verzamelen die nodig is om een eerste indicatie te krijgen van de kwaliteit van een cursus (vak). De quickscan is gebaseerd op literatuuronderzoek en best practices van de faculteiten van de

  6. 68 - 75 Galadanchi et al.c

    African Journals Online (AJOL)

    User

    Restricted HartreeFock (RHF) and Density Functional Theory (DFT) studies were carried out on the organic semi ... arrays), organic light emitting diodes (OLEDs), solar cells and low-cost devices (Kitamura,Arakawa, 2008;. Hwan et al.2004; Byoungnan,2008). Organic semiconductors are materials with semiconducting.

  7. Al Qaeda: Profile and Threat Assessment

    National Research Council Canada - National Science Library

    Katzman, Kenneth

    2005-01-01

    .... interests abroad, and against Western countries. But many believe that the Al Qaeda organization and its leadership are no longer as relevant to assessing the global Islamic terrorist threat as they were on September 11, 2001. Some believe U.S...

  8. 75 FR 3895 - Yale University, et al.;

    Science.gov (United States)

    2010-01-25

    ... DEPARTMENT OF COMMERCE International Trade Administration Yale University, et al.; Notice of Consolidated Decision on Applications for Duty-Free Entry of Electron Microscopes This is a decision consolidated pursuant to Section 6(c) of the Educational, Scientific, and Cultural Materials Importation Act of...

  9. 76 FR 62481 - Incapital LLC, et al.

    Science.gov (United States)

    2011-10-07

    ... SECURITIES AND EXCHANGE COMMISSION [Investment Company Act Release No. 29828; File No. 812-13922] Incapital LLC, et al.; Notice of Application September 30, 2011. AGENCY: Securities and Exchange Commission (``Commission''). ACTION: Notice of application for an order under section 12(d)(1)(J) of the Investment Company...

  10. Correction to Rothermund et al. (2005)

    Science.gov (United States)

    Rothermund, Klaus; Wentura, Dirk; De Houwer, Jan

    2005-01-01

    This article reports an error in the article "Retrieval of Incidental Stimulus-Response Associations as a Source of Negative Priming" by Rothermund et al. ("Journal of Experimental Psychology: Learning, Memory, and Cognition," Vol 31(3) May 2005, 482-495). Table 1 (p. 484) was incorrectly typeset. The correct layout is provided. (The following…

  11. 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…

  12. Uses of a Myth: al-Andalus

    Directory of Open Access Journals (Sweden)

    Serafín Fanjul

    2009-06-01

    Full Text Available In the last two decades, the Spanish press treatment of the Muslim world reflects a change of tone from unsympathetic to enthusiastic, although the information is still marred by confusion and ignorance. This change of attitude has occurred in other Western countries as well, and it is due in part to immigration trends, control over oil resources, and the relativism of official discourses towards the Third World. In the case of Spain, however, there is an additional internal element at play: the mass-media reinvention of a mythical al-Andalus as a tolerant and pluralistic society. This idealized interpretation of seven centuries of Muslim presence in the Iberian Peninsula is fraught with ignorance and distortion of the historical record but is not new. The mystification of al-Andalus has its precedent in romantic accounts that saw in “Muslim Spain” a differential fact that reinforced the exotic image of the country. It can be attributed also to the strategy to “hispanicize” al-Andalus employed by Arabists and historians to make the subject matter appealing to unsympathetic Spanish audiences conditioned by the myth of the Reconquest. Intended or not, the manipulation of the myth of al-Andalus as a historical fact has ideological and political implications that demand an objective and balanced consideration.

  13. The wobbler mouse, an ALS animal model

    DEFF Research Database (Denmark)

    Moser, Jakob Maximilian; Bigini, Paolo; Schmitt-John, Thomas

    2013-01-01

    This review article is focused on the research progress made utilizing the wobbler mouse as animal model for human motor neuron diseases, especially the amyotrophic lateral sclerosis (ALS). The wobbler mouse develops progressive degeneration of upper and lower motor neurons and shows striking...

  14. Thermoluminescence of LaAlO3

    International Nuclear Information System (INIS)

    Morales H, A.; Zarate M, J.; Rivera M, T.; Azorin N, J.

    2015-10-01

    In this paper the thermoluminescent properties of doped lanthanum aluminate (LaAlO 3 ) with dysprosium ion (Dy) were studied. The thermoluminescence characteristics in the samples were obtained using an ultraviolet radiation of 220 nm. The LaAlO 3 :Dy samples were prepared by the modified Pechini method (Spray Dryer). The structural and morphological characterization was obtained by X-ray diffraction (XRD) and scanning electron microscopy (Sem) techniques respectively. The size particle composing the agglomerate was determined by Sem, agglomerated particles composed size of 2μm were observed. The thermoluminescence response of LaAlO 3 :Dy was compared with that obtained with the undoped sample. Thermoluminescence brightness curves of LaAlO 3 :Dy showed a peak centered at 185 grades C. Sensitivity of doped sample was greater, about 100 times compared with the undoped sample. Thermoluminescence response in function of the wavelength showed a maximum at 220 nm. Also the fading in thermoluminescence response was studied. (Author)

  15. Casting of particulate Al-base composites

    International Nuclear Information System (INIS)

    Moustafa, S.F.

    1997-01-01

    A molten Al-4 wt.% Cu as well as a Al-13 wt.% Si alloy have been mixed mechanically with particulate of SiC, Al 2 O 3 , or graphite. After the completion of mixing, each mixture was poured into a permanent mould to solidify. To overcome the problem of non-wettability that exists between the investigated particulate and the molten aluminum alloys the particulate was chemically treated by impregnation in a solution containing Na + ions. The loading of SiC or Al 2 O 3 particulate in the produced composites can be as high as 40 wt.%, and for graphite particles it can be 20 wt.%. The mixing time required to introduce and distribute the investigated particles into the molten matrix was as low as five minutes to recluce chemical reactions at the interfaces between them. Processing details and parameters controlling this technique are described. Metallographic examinations as well as tensile tests were carried out to characterize the microstructure, the distribution of the particles and the strength of these composites. The results display that the composites made by this technique have good microstructure and tensile properties. (orig.)

  16. 1 ITALIAN COLONISATION & LIBYAN RESISTANCE THE AL ...

    African Journals Online (AJOL)

    Ike Odimegwu

    ... was conquered and pacified by European arms, ensuring caravans could travel .... eventually attacked the Order (at Qiru) in 1902 (at which time al-Mahdi passed ... Ottoman rule was nominal, with real power in the hands of the local rulers ...

  17. Una ventana al mundo de Kafka.

    Directory of Open Access Journals (Sweden)

    Guillermo Sánchez Medina

    2003-03-01

    Full Text Available

    COMENTARIO AL LIBRO " EL MUNDO PSICOLÓGICO DE KAFKA" POR EL ACADÉMICO ADOLFO DE FRANCISCO ZEA.

     

    Fui invitado en forma comedida, por el doctor Adolfo De Francisco, para comentar su obra: "El Mundo Psicológico de Kafka". Respondí que no era literato y menos crítico de Kafka. Sin embargo, acepté
    hacerlo siendo consciente de las limitaciones que me acompañan y para las que pido de todos ustedes su consideración. Tenía sí el deseo al reto de lo incógnito.
    Además sus argumentos fueron contundentes, pues se referían al compromiso con la Academia y, sin decírmelo, era también con él en nuestra historia compartida. Mis motivaciones y expectativas personales conscientes eran múltiples para sumergirme en sus ideas que mueven el espíritu desde la piel a lo trascendente, de lo interno a lo externo y viceversa, y en que cada palabra puede ser objeto de análisis profundo, pues esa es su esencia. Por ejemplo cuando el doctor De Francisco se refiere a la sublimación y a la estética, a la política, a la religiosidad, a la burguesía, al campesinado, a la nobleza, al absolutismo, al arte o a la historia, a la cosmovisión sociológica y literaria, al psicoanálisis para afrontar la realidad interna y externa, entonces el autor penetra en el mundo de la fantasía y del psiquismo, para entender el simbolismo implícito de Kafka.
    Las motivaciones personales inconscientes, pertenecen a las tendencias irracionales de hundirme en espacios complejos para luego intentar'ordenarlos; en medio está
    la contratransferencia que me une con el autor Adolfo De Francisco y otra la que se refiere a la temática kafkiana...

  18. Study of the 27Al(n,2,)26Al reaction via accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Wallner, A.

    2000-06-01

    The excitation function for the 27 Al(n,2n) 26 Al reaction is expected to show a strongly non-linear behavior in the neutron-energy region around 14 MeV, the neutron energy in D-T plasmas; thus the production rate of 26 Al (t 1/2 =7.2*10 5 a) in D-T fusion environments can in principle be used to measure the temperature of such plasmas. Existing measurements, however, are strongly discordant. Therefore, a new accurate measurement of the 27 Al(n,2n) 26 Al cross sections in the near threshold region (E n =13.5-14.8 MeV) was performed with the goal to achieve relative cross sections with the highest accuracy possible. In addition, the measurements were also designed to provide good absolute cross-section values, as absolute cross sections are important for radioactive waste predictions. Samples of Al metal were irradiated with neutrons in the energy range near threshold (E th =13.55 MeV) at the Radiuminstitutes of both Vienna and St. Petersburg, and in Tokai-mura, Japan. In Tuebingen irradiations with neutrons of higher energies (17 and 19 MeV) were performed. The amount of 26 Al produced during the irradiations was measured via accelerator mass spectrometry (AMS) at the Vienna Environmental Research Accelerator (VERA). This work represents the first 26 Al measurements for this new facility. With this system, a background as low as 3*10 -15 for 26 Al/ 27 Al isotope ratios was obtained, corresponding to a (n,2n) cross section of 0.04 mb. Utilizing AMS, cross sections with much higher precision and considerably closer to the threshold than in previous investigations could be measured. The prerequisite for its application as a temperature monitor, namely a very well known shape of the excitation function was met. A quantitative prediction of the sensitivity of this method for monitoring the temperature in a D-T fusion plasma was therefore possible. For thermal plasmas temperature changes in the order of 5 to 15 % should be detectable. An even higher sensitivity was found

  19. Medien als Lernform und die Trimediale Redaktion

    Directory of Open Access Journals (Sweden)

    Wolf Hilzensauer

    2015-01-01

    Full Text Available Der vorliegende Artikel beschreibt ein Konzept für eine handlungsorientierte Medienpädagogik im Bildungsbereich. Im Mittelpunkt steht dabei die SO!-Campusredaktion, die als Methode für expansives Lernen die Möglichkeit bietet, unabhängig von Thema oder Medium die Verantwortung für den Lernprozess in die Hände der Lernenden zu legen. Der Dokumentation von Reflexion über den Lernprozess wird dabei eine besondere Bedeutung zugesprochen. Gleichzeitig werden unterschiedliche mediale Gestaltungsmöglichkeiten (Audio/Radio, Video/Fernsehen und Zeitung – sowohl als Print- als auch als Onlinemedium vorgestellt, die durch das Konzept BYOD – bring your own device – auch einfach und niederschwellig im Bildungskontext umsetzbar sind. Dadurch ergeben sich innovative Möglichkeiten, einen Lernprozess sichtbar zu machen und gleichzeitig eine Grundlage für eine alternative Leistungsbeurteilung anzubieten. Die SO!-Campusredaktion wird derzeit an der Pädagogischen Hochschule Salzburg in Kooperation mit dem Communitysender FS1 und der Radiofabrik entwickelt und erprobt. Community Medien nehmen als MedienpartnerInnen eine bedeutende Stellung ein: Durch ihren offenen Zugang zu Know How und Equipment sowie durch die Möglichkeit, Medienproduktionen über die verfügbaren Distibutionskanäle (Radiofrequenz oder Sendeplatz einer breiten Bevölkerung zugänglich zu machen, gewinnt die Medienpädagogik einen wichtigen Mehrwert in ihrer schulischen und außerschulischen Arbeit. (Dieser Artikel knüpft an den Artikel "BYOD, Smartphonefilme und webbasierte Videoschnittprogramme" der Medienimpulse, Ausgabe 2/2014, an.

  20. Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun, E-mail: forsjun@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); He, Xiaoman; Chen, Min; Hu, Huimin [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Zhang, Qiwu, E-mail: zhangqw@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Liu, Xinzhong [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350118 China (China)

    2017-04-15

    In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu{sub 2}(OH){sub 2}CO{sub 3}) and aluminum hydroxide (Al(OH){sub 3}) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.

  1. Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides

    International Nuclear Information System (INIS)

    Qu, Jun; He, Xiaoman; Chen, Min; Hu, Huimin; Zhang, Qiwu; Liu, Xinzhong

    2017-01-01

    In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu_2(OH)_2CO_3) and aluminum hydroxide (Al(OH)_3) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.

  2. PRECIPITATION HARDENING IN B2-ORDERED NiAl BY Ni2AlTiCOMPOUND

    Institute of Scientific and Technical Information of China (English)

    W.H. Tian; K. Ohishi; M. Nemoto

    2001-01-01

    Microstructural variations and correlated hardness changes in B2-ordered NiAl containing fine precipitation of Ni2AlTi have been investigated by means of transmission electron microscopy (TEM) and hardness tests. The amount of age hardening is not large as compared to the large microstructural variations during aging. TEM observations have revealed that the L21-type Ni2AlTi precipitates keep a lattice coherency with the NiAl matrix at the beginning of aging. By longer periods of aging Ni2AlTi precipitates lose their coherency and change their morphology to the globular ones surrounded by misfit dislocations. The temperature dependence of the yield strength of precipitate-containing B2-ordered NiAl was investigated by compression tests over the temperature range of 873-1273K. The fine precipitation of Ni2AlTi was found to enhance greatly the yield strength and the high-temperature strength is comparison with that of superalloy Mar-M200.``

  3. Superstructure formation in PrNi_2Al_3 and ErPd_2Al_3

    International Nuclear Information System (INIS)

    Eustermann, Fabian; Hoffmann, Rolf-Dieter; Janka, Oliver; Oldenburg Univ.

    2017-01-01

    The intermetallic phase ErPd_2Al_3 was obtained by arc-melting of the elements and subsequent annealing for crystal growth. The sample was studied by X-ray diffraction on powders and single crystals. The structure of ErPd_2Al_3 was refined from X-ray diffraction data and revealed a superstructure of PrNi_2Al_3 - a CaCu_5 derivative (P6/m, a=1414.3(1), c=418.87(3) pm wR=0.0820, 1060 F"2 values, 48 variables). The same superstructure was subsequently found for PrNi_2Al_3 (P6/m, a=1407.87(4), c=406.19(2) pm, wR=0.0499, 904 F"2 values, 47 variables). In the crystal structure, the aluminium and transition metal atoms form a polyanionic network according to [T_2Al_3]"δ"-, while rare earth atoms fill cavities within the networks. They are coordinated by six transition metal and twelve aluminum atoms. In contrast to the PrNi_2Al_3 type structure reported so far, two crystallographic independent rare-earth sites are found of which one (1b) is shifted by 1/2 z, causing a distortion in the structure along with a recoloring of the T and Al atoms in the network.

  4. Stagnation of the exploitation of Al ores and the depression of world prices of Al

    Directory of Open Access Journals (Sweden)

    Slavkovský Jozef

    1999-03-01

    Full Text Available In the contribution, data on Al – a metal of the 20th century are compiled together with the problems of genesis of the Al mineral raw ma-terials as well as types of bauxite and Al-laterite deposits. Furthermore, an overview of the world exploitation of bauxite during 1935-1980 is given along with the prognoses to 2000 and present situation (1992-1996. Overviews of the production of Al follows, providing its rela-tion to the bauxite exploitation. Contrary to the prognoses, a stabilization or stagnation has been observed in the exploitation of bauxite and production of Al during nineties, which a tendency is directly reflected in the world price of this commodity. When analyzing the Al prices for a longer period, some serious deviations can be noticed, that however presently represent a long-term minimum. We hope the stagnation of the production and the price decline are only temporary and new possibilities of the utilization of Al will be found soon.

  5. Pemikiran Politik al-Shawkânî dalam Fath al-Qadîr

    Directory of Open Access Journals (Sweden)

    Yusuf Hanafi

    2015-09-01

    Full Text Available Muhammad b. ‘Alî Muhammad b. ‘Abd Allâh al-Shawkânî al-San‘ânî. He was born in the Hijrah in Shawkân village, Yemen on Monday 28 Dhû al-Qa‘dah 1172 H and died on Tuesday, 27 Jumâd al-Akhîr 1250 H at the age about 78 years. Al-Shawkânî grew up in the San‘a city, it is the capital of the republic of Yemen now. He study first time about religion from his father, then from renowed scholars in San‘a and its surrounding, he was known as a scolar who mastered the various branches of religious sciences. Such as tafsîr, h}adîth, fiqh, us}ûl al-fiqh, history, science of kalâm, philosophy, balâghah, mant}iq etc. the main issue in this article is how political thought in the book of tafsir Fath al-Qadîr is the work of Shawkânî. At the end of article, the authors found that the intended political thinking in the study of Fath al-Qadîr is about constitutional ideas. These ideas about the constitution is limited to the concept of leadership and deliberation, the concept of the right of citizen to obtain justice, and the concept pf the right of citizens to live association and assembly

  6. Mechanical Properties and Microstructure of Neutron Irradiated Cold-worked Al-1050 and Al-6063 Alloys

    International Nuclear Information System (INIS)

    Munitz, A.; Cotler, A; Talianker, M.

    1998-01-01

    The impact of neutron irradiation on the internal microstructure, mechanical properties and fracture morphology of cold-worked Al-1050 and Al-6063 alloys was studied, using scanning and transmission electron microscopy, and tensile measurements. Specimens consisting of 50 mm long and 6 mm wide gauge sections, were punched out from Al-1050 and Al-6063 23% cold-worked tubes. They were exposed to prolonged neutron irradiation of up to 4.5x10 25 and 8x10 25 thermal neutrons/m 2 (E -3 s -1 . In general, the uniform and total elongation, the yield stress, and the ultimate tensile strength increase as functions of fluence. However, for Al-1050 a decrease in the ultimate tensile strength and yield stress was observed up to a fluence of 1x10 25 thermal neutrons/m 2 which then increase with thermal neutrons fluence. Metallographic examination and fractography for Al-6063 revealed a decrease in the local area reduction of the final fracture necking. This reduction is accompanied by a morphology transition from ductile transgranular shear rupture to a combination of transgranular shear with intergranular dimpled rupture. The intergranular rupture area increases with fluence. In contrast, for Al-1050, fracture morphology remains ductile transgranular shear rupture and the final local area reduction remains almost constant No voids could be observed in either alloy up to the maximum fluence. The dislocation density of cold-worked Al was found to decrease with the thermal neutron fluence. Prolonged annealing of unirradiated cold-worked Al-6063 at 52 degree led to similar results. Thus, it appears that, under our irradiation conditions, whereby the temperature encompassing the samples increases the exposure to this thermal field is the major factor influencing the mechanical properties and microstructure of aluminum alloys

  7. Thermodynamic assessment of the Al-Ru system

    CSIR Research Space (South Africa)

    Prins, SN

    2003-03-01

    Full Text Available describes the order disorder transformation with one Gibbs energy function. The RuAl6 phase was described as a stoichiometric phase and the remaining intermetallic phases (Ru4Al13, RuAl2 and Ru2Al3) were modelled with the sublattice model. The solubility...

  8. 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

  9. Mechanical properties and electronic structures of Fe-Al intermetallic

    Energy Technology Data Exchange (ETDEWEB)

    Liu, YaHui; Chong, XiaoYu; Jiang, YeHua, E-mail: jiangyehua@kmust.edu.cn; Zhou, Rong; Feng, Jing, E-mail: jingfeng@kmust.edu.cn

    2017-02-01

    Using the first-principles calculations, the elastic properties, anisotropy properties, electronic structures, Debye temperature and stability of Fe-Al (Fe{sub 3}Al, FeAl, FeAl{sub 2}, Fe{sub 2}Al{sub 5} and FeAl{sub 3}) binary compounds were calculated. The formation enthalpy and cohesive energy of these Fe-Al compounds are negative, and show they are thermodynamically stable structures. Fe{sub 2}Al{sub 5} has the lowest formation enthalpy, which shows the Fe{sub 2}Al{sub 5} is the most stable of Fe-Al binary compounds. These Fe-Al compounds display disparate anisotropy due to the calculated different shape of the 3D curved surface of the Young’s modulus and anisotropic index. Fe{sub 3}Al has the biggest bulk modulus with the value 233.2 GPa. FeAl has the biggest Yong’s modulus and shear modulus with the value 296.2 GPa and 119.8 GPa, respectively. The partial density of states, total density of states and electron density distribution maps of the binary Fe-Al binary compounds are analyzed. The bonding characteristics of these Fe-Al binary compounds are mainly combination by covalent bond and metallic bonds. Meanwhile, also exist anti-bond effect. Moreover, the Debye temperatures and sound velocity of these Fe-Al compounds are explored.

  10. High temperature properties of the Cr-Nb-Al-N coatings with increasing Al contents

    OpenAIRE

    Li, W. Z.; Polcar, T.; Evaristo, M.; Cavaleiro, A.

    2013-01-01

    Cr-Nb-Al-N coatings with Al content from 0 to 12 at.% were deposited by d.c. reactive magnetron sputtering. The coatings were annealed in protective atmosphere at 800 and 900 °C for 1 h and exposed to air at 800, 900 and 1200 °C for different times. The chemical composition, structure, microstructure, hardness and adhesive/cohesive strength of the coatings, in as-deposited and annealed conditions, were investigated and the oxidation resistance was evaluated. As expected, the Al content increa...

  11. Structure of 26Al studied by one - nucleon transfer reaction 27Al(d,t

    Directory of Open Access Journals (Sweden)

    Srivastava Vishal

    2015-01-01

    Full Text Available The excited states of 26Al have been produced and studied using 27Al(d,t reaction with 25 MeV deuteron as projectile. Optical model potential parameters were extracted from the measured elastic scattering angular distribution. Zero range distorted wave Born approximation analysis for the ground and 0.223 MeV states of 26Al have been done. The spectroscopic factors calculated for these states are found to be in good agreement with the previously reported values.

  12. ITIJAHAT KAUN AL-NABI WA AL-RASUL FI SYAKHSIYAH MUHAMMAD FI NATSR MAULID AL-BARZANJI

    Directory of Open Access Journals (Sweden)

    Himmah Istomah

    2017-08-01

    Full Text Available One of human personalities is humanist. Based on the understanding of Maslow’s theory of motivation, researcher seeks to uncover kinds of motivational needs of Muhammad Saw contained in Maulid Al-Barzanjiy (the work of Ja 'far bin Hasan al-Barzanji (d. 1763 M. The goal is realized through a descriptive qualitative approach with  text analysis  about Psycholiterature of Endraswara. The results of this study indicate that in Maulid Al-Barzanji there are Muhammad Saw’s five needs and how their satisfying perfectly,  namely: physiological needs, safety, social, esteem, and self-actualization. Thus, it can be interpreted that Muhammad SAW as an ordinary human having motivational needs. His prophetic and apostleship honor is not a direct blessing from Allah, but he had been through some complicated processes in life. This can be applied by his followers, so they can complete their motivational needs to reach the satiation as a caliph and to be useful person in this world.

  13. Solidification processing of intermetallic Nb-Al alloys

    Science.gov (United States)

    Smith, Preston P.; Oliver, Ben F.; Noebe, Ronald D.

    1992-01-01

    Several Nb-Al alloys, including single-phase NbAl3 and the eutectic of Nb2Al and NbAl3, were prepared either by nonconsumable arc melting in Ar or by zone processing in He following initial induction melting and rod casting, and the effect of the solidification route on the microstructure and room-temperature mechanical properties of these alloys was investigated. Automated control procedures and melt conditions for directional solidification of NbAl3 and the Nb2Al/Nb3Al eutectic were developed; high purity and stoichiometry were obtained. The effects of ternary additions of Ti and Ni are described.

  14. Environmental embrittlement of intermetallic compounds in Fe-Al alloys

    Institute of Scientific and Technical Information of China (English)

    张建民; 张瑞林; S.H.YU; 余瑞璜

    1996-01-01

    First,it is proposed that hydrogen atoms occupy the interstitial sites in Fe3Al and FeAl.Then the environmental embrittlement of intermetallic compounds in Fe-Al alloys is studied in the light of calculated valence electron structures and bond energy of Fe3Al and FeAl containing hydrogen atoms.From the analyses it is found that the states of metal atoms will change,in which more lattice electrons will become covalent electrons to bond with hydrogen atoms when the atomic hydrogen diffuses into the intermetallic compounds in Fe-Al alloys,which will result in the decrease of local metallicity in Fe3Al and FeAl.Meanwhile,it is found that the crystal will easily cleave since solute hydrogen bonds with metal atoms and severely anisotropic bonds form.As a conclusion,these factors result in the environmental embrittlement of Fe3Al and FeAl.

  15. Gate length scaling effect on high-electron mobility transistors devices using AlGaN/GaN and AlInN/AlN/GaN heterostructures.

    Science.gov (United States)

    Liao, S Y; Lu, C C; Chang, T; Huang, C F; Cheng, C H; Chang, L B

    2014-08-01

    Compared to AlGaN/GaN HEMT with 0.15 μm T-gate length, the AlInN/AlN/GaN one exhibits much higher current density and transconductance of 1558 mA/mm at Vd = 2 V and 330 mS/mm, respectively. The high extrinsic ft and fmax of 82 GHz and 70 GHz are extracted from AlInN/AlN/GaN HEMT. Besides, we find that the transconductance roll-off is significant in AlGaN/GaN, but largely improved in AlInN/AlN/GaN HEMT, suggesting that the high carrier density and lattice-matched epitaxial heterostructure is important to reach both large RF output power and high operation frequency, especially for an aggressively gate length scaling.

  16. Study of the AlON-VN composite ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Sainbaatar; Zhang Zuotai; Li Wenchao; Wang Xidong [Dept. of Physical Chemistry of Metallurgy, Univ. of Science and Technology Beijing, BJ (China)

    2005-07-01

    Aluminium oxynitride-vanadium nitride (AlON-VN) composite ceramic was fabricated based on thermodynamic analysis of V-Al-O-N systems. The results indicated that the VN dispersed homogeneously in AlON matrix and can reinforce AlON matrix. Oxidation behavior was studied and the results showed that it belongs to self-protective oxidation due to the good adherence of oxidation product. Therefore, AlON-VN composites have excellent oxidation resistance. (orig.)

  17. ALS1 and ALS3 gene expression and biofilm formation in Candida albicans isolated from vulvovaginal candidiasis

    Directory of Open Access Journals (Sweden)

    Shahla Roudbarmohammadi

    2016-01-01

    Conclusion: The results attained indicated that there is an association between the expression of ALS1 and ALS3 genes and fluconazole resistance in C. albicans. A considerable percent of the isolates expressing the ALS1 and ALS3 genes may have contributed to their adherence to vagina and biofilm formation.

  18. Studies in the Crystalline Electric Field in Pr2 Al and Pr Al by the Inelastic Neutron Scattering Method

    International Nuclear Information System (INIS)

    Slisenko, V.I.; Ivanitskij, P.G.; Vasil'kevich, A.A.; Krotenko, V.T.; Majstrenko, A.N.

    1993-01-01

    Results of inelastic neutron scattering in polycrystalline Pr 2 Al and Pr Al are reported. The parameters of the crystal field Hamiltonian for the orthorhombic point symmetry of the Pr 3+ ions in Pr 2 Al and Pr Al are derived from neutron spectra. Using These parameters the magnetic contribution to the specific heat is calculated

  19. The extraordinary role of the AlN interlayer in growth of AlN sputtered on Ti electrodes

    NARCIS (Netherlands)

    Tran, Tuan; Pandraud, G.; Tichelaar, F.D.; Nguyen, Duc Minh; Schellevis, H.; Sarro, P.M.

    2013-01-01

    The structure of AlN layers grown on Ti with and without an AlN interlayer between the Si substrate and the Ti layer is investigated. The AlN grains take over the orientation of the Ti columnar grains in both cases. Surprisingly, the Ti grains do not take over completely the orientations of the AlN

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

    Directory of Open Access Journals (Sweden)

    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