Datos experimentales de la cinética del secado y del modelo matemático para pulpa de cupuaçu (Theobroma grandiflorum en rodajas Kinetic drying experimental data and mathematical model for cupuaçu pulp (Theobroma grandiflora slices

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Abraham Damian Giraldo-Zuniga

2010-03-01

Full Text Available En este trabajo fueron obtenidos experimentalmente la cinética del secado de la pulpa de cupuaçu en forma de rodajas con espesor de 0,5 cm. El secado fue realizado utilizándose un secador laboratorial de bandejas, a las temperaturas de 50, 60 y 70 ºC y a la velocidad del aire de secado de 1,5 m/s. De acuerdo con los datos de la cinética del secado se puede observar que cuanto mayor es la temperatura del secado mayor es la velocidad del secado. El tiempo requerido para secar el producto hasta una humedad del 20%, fueron 9,2, 8,1 y 7,3 horas para las temperaturas de secado de 50, 60 y 70 ºC respectivamente. Las curvas experimentales del secado fueron ajustados al modelo difusional de Fick considerándose la muestra como una lámina infinita y al modelo de Page. Los dos modelos se ajustaron bien a los datos experimentales. Los coeficientes de difusión del modelo de Fick variaron de 1.171 a 1.561 m/s².This work examined experimentally the kinetics of drying cupuaçu pulp (Theobroma grandiflorum slices. The experimental runs were driven in a laboratory dryer, at temperatures of 50, 60 and 70 ºC and an air drying velocity of 1.5 m/s. According to the kinetics study, increasing the temperature led to a decrease in drying time. The required drying times were 9.2, 8.1 and 7.3 hours for drying temperatures of 50, 60 and 70 ºC respectively. The experimental drying curves were adjusted to Fick's diffusional model for an infinite lamina with shrinkage and Page model. The diffusion coefficients of the Fick model varied between 1.171 and 1.561 m/s².

Cocoa Bean (Theobroma cacao L.Drying Kinetics Cinética del Secado de Cocoa (Theobroma cacao L.

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Ndukwu MacManus Chinenye

2010-12-01

Full Text Available Cocoa (Theobroma cacao L. is widely produced in West Africa and South America and is a great economic tree crop, with so many industrial uses. In this work, the experimental drying kinetics of foreign species was investigated, and the experiments were carried out under isothermal conditions, using heated batch drier at 55, 70 and 81 ºC. The moisture ratio data obtained from change of moisture content with the drying time was fit to two thin layer drying model with good results. A faster drying process was observed at a higher drying temperature resulting in higher drying rates which is advantageous when evaluating costs. Fick’s second law of diffusion was used to predict effective diffusivity using experimental data assuming that the variation of diffusivity with temperature can be expressed by an Arrhenius type function, and the values of diffusivity obtained ranged from 6.137 x 10-10 to 2.1855 x 10-9 m2 s-1 for the temperature used. The Arrhenius constant (D is predicted at 8.64 x 10-4 m2 s-1 while the activation energy was predicted at 39.94 kJ mol-1.El cacao (Theobroma cacao L. es ampliamente producido en el Oeste de África y Sudamérica y es un cultivo de gran importancia económica, con muchos usos industriales. En este trabajo se investigó la cinética del secado experimental de especies foráneas, y se realizaron experimentos bajo condiciones isotérmicas, usando un secador discontinuo en caliente a 55, 70 y 81 °C. Los datos de relación de humedad obtenidos desde el cambio de contenido de humedad con el tiempo de secado se ajustaron a un modelo de secado de dos capas delgadas con buenos resultados. Se observó un proceso de secado más rápido a una temperatura de secado mayor resultando en mayores tasas de secado, lo que es ventajoso al evaluar costos. La segunda ley de difusión de Fick se usó para predecir difusividad efectiva usando datos experimentales, asumiendo que la variación de difusividad con la temperatura puede ser

Solar drying: An appropriate technology for the north Argentina; Secado solar: Una tecnologia apropiada para el norte argentino

Energy Technology Data Exchange (ETDEWEB)

Zurlo, Hugo D; Vergara, Liliana; Spotorno, Ruben; Benitez, Francisco; De Pedro, Jorge; Cervino, Veronica; Monzon, Sergio [Universidad Tecnologica Nacional, Chaco (Argentina)

2000-07-01

The results concerning to solar drying of nutritious products for rehearsed a low cost solar dryer, adapted to the area, composed by a plane solar collector of 2 m{sup 2} and a drying camera with capacity for, approximately, 5 kg of product. The objectives of the work were: a) to develop a low cost solar dry, capable to dehydrate products for human alimentary use; b) to transfer the developed technology to low resources rural communities through the INCUPO (Institute of Popular Culture) and to small producers through the INTA (National Institute of Agricultural Technology) and c) to diffuse the practice of the solar drying among small producers. The diffusion and transfer of the developed technology to small rural producers, contribute to improve their quality of life when facilitating them additional revenues for productive diversification, besides the contribution to the sustainable use of the forest like source of non conventional nutritious resources contributing to the task of cultural rescue faced by organizations like the INCUPO. [Spanish] Se exponen los resultados concernientes al secado solar de productos alimenticios para consumo humano. Se diseno, construyo y ensayo un secador solar de bajo costo, adaptado a la zona, compuesto por un colector solar plano de 2m{sup 2} y una camara de secado con capacidad para, aproximadamente, 5 kg de producto fresco. Los objetivos del trabajo fueron: a) desarrollar un secadero solar de bajo costo, apto para deshidratar productos para uso alimentario humano; b) transferir la tecnologia desarrollada a comunidades rurales de bajos recursos a traves del INCUPO (Instituto de Cultura Popular) y a pequenos productores a traves del INTA (Instituto Nacional de Tecnologia Agropecuaria) y c) difundir la practica del secado solar entre productores frutihorticolas. La difusion y transferencia de la tecnologia desarrollada a pequenos productores rurales, contribuye a mejorar su calidad de vida al posibilitarles ingresos adicionales

Potencial de secado de yuca con aire natural y energía solar

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Alfonso Parra Coronado

1990-01-01

Full Text Available En este trabajo se presentan los resultados de estudios del potencial de secado de productos agropecuarios con aire natural y energía solar de regiones tropicales, considerando el caso específico de la yuca. La evaluación del potencial de secado de una región se basa en el uso de un programa de computador  Simulación matemática, mediante el cual se obtienen los valores del caudal mínimo de aire requerido para secar el producto antes que éste alcance un nivel de deterioro preestablecido. Otros elementos metodológicos incluyen: manejo de la información meteorológica, mes crítico, patrón de agitación del producto, hora de iniciación del secado, patrón de operación del ventilador, uso de calor suplementario (energía solar e interpretación de los resultados con el fin de optimizar el sistema. Se presentan mapas para Colombia de líneas isocaudales e isoáreas de colector solar plano, con base en los cuales se puede obtener fácilmente la información requerida para el diseño de sistemas de secado de yuca a baja temperatura.

Velocidad de secado en pilas de mena laterítica almacenadas a la intemperie

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Yoalbys Retirado-Mediaceja

2015-10-01

Full Text Available En este trabajo se establece, a partir del balance de energía térmica y el análisis de la transferencia de calor y masa en el secado natural, el modelo matemático para el cálculo y la simulación de la velocidad de secado en pilas de mena laterítica almacenadas a la intemperie, en la empresa productora de níquel y cobalto Comandante Ernesto Che Guevara de Moa. Las simulaciones evidenciaron que la velocidad de secado en las pilas fue, generalmente, inferior a 0,05 %/h y nula en determinados horarios de la mañana y la tarde en los taludes oeste y este, respectivamente.

Correlaciones de parámetros medios de proceso para el secado de productos agropecuarios en cama fina en secadores solares directos

OpenAIRE

Bergues-Ricardo, Ciro César; Díaz-López, José Raúl; Torres-Ten, Alonso

2013-01-01

Se da un grupo de correlaciones entre la velocidad media de secado, las pérdidas de energía, la energía útil y la eficiencia térmica media del proceso, válidas para condiciones de secado en cama fina en secadores solares directos, y contribuyen a un enfoque integral del secado solar en estas condiciones. Ellas son válidas para procesos de secado de diversos productos agropecuarios tales como viandas, vegetales, frutas, granos y madera con convección natural o forzada. Las correlaciones fueron...

Efecto del método de secado en la longevidad y la calidad de las semillas de Bauhinia purpurea.: I. Almacenamiento en Condiciones Ambientales Effect of the drying method on the longevity and quality of seeds from Bauhinia purpurea.: I. Storage under ambient conditions

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Marlen Navarro

2007-11-01

Full Text Available Se realizó un experimento con el objetivo de determinar la influencia combinada de diferentes métodos de secado, las condiciones de almacenamiento al ambiente y la edad fisiológica de las semillas de B. purpurea, en la capacidad germinativa y en la calidad de estas. Los tratamientos para el secado fueron: A en las legumbres, B artificial, y C al sol. Se determinó el porcentaje de viabilidad y de germinación, así como el contenido de humedad (CH, con una frecuencia mensual durante un año de almacenamiento; además se registró la temperatura y la humedad relativa (máxima y mínima durante el período evaluado. En el procesamiento de la información se utilizaron análisis multivariados (GLM y Factorial. En los tratamientos A y C se observaron semejanzas en cuanto a la viabilidad y la germinación, aunque las semillas alcanzaron la muerte fisiológica a los siete y nueve meses de permanencia en el almacén, respectivamente. El secado de las semillas con silicagel mostró que la pérdida de la capacidad germinativa siguió un modelo polinomial cúbico, con una marcada tendencia a la linealidad, y al finalizar el estudio fue de 70%. Las diferencias entre el CH de las semillas secadas artificialmente (B y al sol (C permitieron confirmar que la longevidad en B fue dos a cuatro veces mayor que en C. Los factores más influyentes en el ritmo de pérdida de la calidad de las semillas B. purpurea almacenadas al ambiente fueron el contenido de humedad y la edad.A trial was carried out with the objective of determining the combined influence of different drying methods, the storage under ambient conditions and the physiological age of the seeds from B. purpurea, on their germination capacity and quality. The treatments for drying were: A in the pods, B artificial and C under sunlight. The percentage of viability and germination, as well as the moisture content (MC, were determined, with a monthly frequency during a year of storage; in addition the

Parámetros de Transferencia de Materia en el Secado de Frutas Mass Transfer Parameters in Fruit Drying

OpenAIRE

Sebastião R Ferreira; Antônio R. S Costa

2009-01-01

Se desarrolló un modelo analítico para obtención de parámetros de transferencia de materia en el secado de frutas. El modelo considera la disminución del radio de las frutas durante el proceso de secado. Con el modelo matemático se predice simultánemente el coeficiente externo de transferencia de materia k m y la difusividad de agua en los frutos D AB. Para probar el modelo se obtuvo en forma expermental datos de masa de agua M A en la fruta versus el tiempo de secado t, además del radio inic...

PROPIEDADES TÉCNICO-FUNCIONALES DE LA FIBRA DIETARIA DE CÁSCARAS DE MANGO VARIEDADHILACHA (Mangifera indica L.: EFECTO DEL SECADO POR CONVECCIÓN

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GUSTAVO ADOLFO HINCAPIÉ LL.

2014-06-01

Full Text Available Un subproducto de la obtención del jugo de mango es su cáscara; la cual contiene niveles considerables de fibra dietaria que podrían ser utilizados en la elaboración de productos alimenticios, sin embargo, actualmente no es muy aprovechado. El proceso de secado prolonga la vida útil de la cascara y permite que pueda ser adicionada a otros alimentos. En este estudio, se caracterizó fisicoquímicamente la Cáscara de Mango Hilacha (CMH y se evaluó el efecto de cinco temperaturas de secado sobre las propiedades técnico-funcionales de la fibra dietaria; Capacidad de Hinchamiento (CH, Capacidad de Retención de Agua (CRA y Capacidad de Adsorción de Lípidos (CAL, características que determinan en gran medida la calidad de la fibra dietaria (FD. Los resultados obtenidos indican que la CMH tiene un contenido de fibra dietaria total, proteína, extracto etéreo, carbohidratos y fibra cruda similar al de otras variedades de mango. La cáscara de mango hilacha seca y molida (CSMH obtenida, es una promisoria fuente de FD, ya que su calidad no se vio afectada significativamente por el proceso de secado empleado en este trabajo.

Comportamiento de la humedad durante el secado solar del mineral laterítico

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Arturo L. Rojas-Purón

2007-03-01

Full Text Available En las empresas cubanas del níquel que utilizan el proceso Caron, el contenido elevado de humedad en la material prima mineral incide en el aumento del consumo de combustible en los secadores durante el secado térmico. Se evaluó de forma experimental la humedad durante el secado solar del mineral laterítico a la intemperie. El método de análisis de la humedad utilizado fue el de diferencias de pesadas. Se empleó la regression lineal multiple para establecer los modelos matemáticos de las masas de trabajo. El estudio demostró que los parámetros climatológicos más influyentes en el secado solar del mineral laterítico son la temperatura del medio ambiente, las precipitaciones, la velocidad del viento y la temperatura del punto de rocío, así como que solamente el agua no estructural es la que puede ser eliminada. La humedad se redujo en un 13 %.

Surface analysis and biocorrosion properties of nanostructured surface sol-gel coatings on Ti6Al4V titanium alloy implants.

Science.gov (United States)

Advincula, Maria C; Petersen, Don; Rahemtulla, Firoz; Advincula, Rigoberto; Lemons, Jack E

2007-01-01

Surfaces of biocompatible alloys used as implants play a significant role in their osseointegration. Surface sol-gel processing (SSP), a variant of the bulk sol-gel technique, is a relatively new process to prepare bioreactive nanostructured titanium oxide for thin film coatings. The surface topography, roughness, and composition of sol-gel processed Ti6Al4V titanium alloy coatings was investigated by atomic force microscopy (AFM) and X-ray electron spectroscopy (XPS). This was correlated with corrosion properties, adhesive strength, and bioreactivity in simulated body fluids (SBF). Electroimpedance spectroscopy (EIS) and polarization studies indicated similar advantageous corrosion properties between sol-gel coated and uncoated Ti6Al4V, which was attributed to the stable TiO2 composition, topography, and adhesive strength of the sol-gel coating. In addition, inductive coupled plasma (ICP) and scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) analysis of substrates immersed in SBF revealed higher deposition of calcium and phosphate and low release rates of alloying elements from the sol-gel modified alloys. The equivalent corrosion behavior and the definite increase in nucleation of calcium apatite indicate the potential of the sol-gel coating for enhanced bioimplant applications. 2006 Wiley Periodicals, Inc.

Effects of inorganic acids and divalent hydrated metal cations (Mg(2+), Ca(2+), Co(2+), Ni(2+)) on γ-AlOOH sol-gel process.

Science.gov (United States)

Zhang, Jian; Xia, Yuguo; Zhang, Li; Chen, Dairong; Jiao, Xiuling

2015-11-07

In-depth understanding of the sol-gel process plays an essential role in guiding the preparation of new materials. Herein, the effects of different inorganic acids (HCl, HNO3 and H2SO4) and divalent hydrated metal cations (Mg(2+), Ca(2+), Co(2+), Ni(2+)) on γ-AlOOH sol-gel process were studied based on experiments and density functional theory (DFT) calculations. In these experiments, the sol originating from the γ-AlOOH suspension was formed only with the addition of HCl and HNO3, but not with H2SO4. Furthermore, the DFT calculations showed that the strong adsorption of HSO4(-) on the surface of the γ-AlOOH particles, and the hydrogen in HSO4(-) pointing towards the solvent lead to an unstable configuration of electric double layer (EDL). In the experiment, the gelation time sequence of γ-AlOOH sol obtained by adding metal ions changed when the ionic strength was equal to or greater than 0.198 mol kg(-1). The DFT calculations demonstrated that the adsorption energy of hydrated metal ions on the γ-AlOOH surface can actually make a difference in the sol-gel process.

Estudio regional del potencial de secado con aire natural y energía solar

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Jorge Domínguez P.

1983-09-01

Full Text Available En este artículo se presenta y aplica una metodología de trabajo basada en la técnica de simulación matemática y desarrollada con el fin de realizar estudios sobre el potencial de secado de productos agropecuarios con aire natural y energía solar de regiones tropicales. La metodología se basa en el uso de un programa de computador e Incluye otros elementos metodológicos en relación con el manejo de la información meteorológica, el patrón de operación del ventilador, el uso de energía solar y la interpretación de los resultados con el fin de optimizar el sistema. Se reportan los resultados del estudio del potencial de secado con aire natural y energía solar de Tuluá (Valle y se proporcionan recomendaciones específicas para la implementación de sistemas de secado a bala temperatura en la Reglón.

Evaluación de un Secador Intermitente de Flujos Concurrentes (IFC para Café

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Ospina Machado Julio E.

1991-09-01

Full Text Available En Colombia, el secado de café pergamino, beneficiado por vía húmeda se realiza en dos sistemas: al sol y mecánico. El secado mecánico más utilizado es el estático, el cual presenta algunas desventajas, entre ellas, la desuniformidad en el contenido de humedad final del grano. Con el fin de disponer de una tecnología alterna de secado, el Centro Nacional de Investigaciones del Café (CENICAFE, desarrolló un proyecto de investigación sobre secado dinámico, para lo cual diseñó y evaluó un secador intermitente de flujos concurrentes (FC. En este trabajo se presentan los resultados de la evaluación de un secador tipo IFC de capacidad de 500 kg de café pergamino seco (c.p.s. y el sistema de transporte utilizado durante el secado. Las diferencias del contenido de humedad final de la masa de grano fue menor al 1% base seca (b.s. Las mejores condiciones de operación del secador fueron: temperatura del aire de secado, 80°C; flujo de grano, 0,04 m3/ min.m2 (volumen de grano; flujo de aire, 210 m3 / min.ton de café pergamino seco y tiempo de secado, 28 horas; incluyendo dos horas de aireación al final del proceso. Como resultado del análisis de calidad del café pergamino seco se encontró un promedio de 0,6% de grano pelado y una cantidad de pasillas en la almendra inferior al 5%. Después de cuatro meses de almacenamiento del café, en condiciones ambientales diferentes, la prueba de taza dio un café bueno (aroma. y sabor normal. El consumo de combustible (ACP M en promedio fue de 0,5 galones por hora y un rendimiento térmico de 5.600 KJ/ kg de agua evaporada. El transportador de cangilones de descarga por gravedad demostró ser una buena alternativa para mover el grano en este sistema de secado.

Diseño e implementación de una estrategia de control predictivo para el secado de arroz paddy

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Alfonso Cubillos Varela

2010-01-01

Full Text Available Este artículo trata sobre la modelación y control del proceso de secado de arroz Paddy en silo inclinado usando técnicas de control predictivo. Para esto se usa un secador a escala 1,10 con capacidad de 25 kilos de grano, totalmente instrumentado donde se puede medir en línea la temperatura y humedad del grano de arroz y del medio ambiente. Además, permite medir y manipular el flujo y temperatura del aire de secado. Con el fin de diseñar el controlador, primero se obtiene un modelo dinámico basado en el principio de capa delgada, luego se diseña e implementa la estrategia de control predictivo, conocida como DMC (Dynamic Matriz Control la cual utiliza la respuesta paso y repuesta libre del sistema para calcular la acción de control óptima. Como consecuencia de este proceso se obtienen resultados prometedores del uso de este tipo de tecnología en el secado de arroz Paddy, a reducción del tiempo de secado, b evitar la pérdida de masa por sobresecado, c garantizar un secado más homogéneo y por lo tanto una mejora en la calidad del arroz y la productividad de la industria molinera de la Región.

Secado de jugos en la industria azucarera como alternativa de diversificación sostenible

OpenAIRE

Felipe Campo; Angela O. Díaz; Yoel Hernández; Dayami Borges

2010-01-01

Se ofrece y comenta una información actualizada sobre los diferentes procesos desarrollados y equipos empleados para el secado de jugos de frutas y de caña. Se hace énfasis en este último y en el empleo de sistemas de secado por gas-suspensión, por constituir estos procesos una simplificación tecnológica del proceso tradicional de producción de azúcar. Se disminuye el número de etapas, equipos, los consumos y el tiempo de duración. Se elimina el empleo de productos químicos y la obtención de ...

Lithium containing MgAl mixed oxides obtained from sol-gel hydrotalcite for transesterification

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Renata A. B. Lima-Corrêa

Full Text Available Abstract The innumerous advantages of heterogeneous catalysts employed in biodiesel production have stimulated the search for a solid catalyst capable of replacing the industrially used homogeneous catalysts. This paper investigates the effect of the sol-gel method in the catalytic activity and stability of Li-MgAl mixed oxides prepared by the “in situ” lithium addition to a MgAl hydrotalcite. The analyses based on N2 physisorption, thermogravimetric analysis, X-ray diffractometry, scanning electron microscopy and temperature-programmed desorption of CO2 were carried out to elucidate the properties of the catalysts. Considerable differences in the physico-chemical properties of the catalysts were observed with the Li addition. Li reduced the surface area and increased the crystallite size of the oxides. Furthermore, Li-MgAl mixed oxides prepared by the calcination of the sol-gel MgAl hydrotalcites presented substantial morphological differences when compared to the same oxides obtained by heat treatment of hydrotalcites synthesized via the conventional co-precipitation route. Furthermore, Li increased the number and strength of the base sites which resulted in the increase of the oxide reactivities towards the transesterification reaction between methyl acetate and ethanol. The activity was dependent on the Li loading on the catalysts. The catalyst containing only 5 wt.% Li turned out to be highly active (( 85% conversion at 50°C, ethanol/methyl acetate molar ratio = 6/1, 4 wt.% of catalyst and 30 min of reaction. Stability tests showed that the Li-MgAl catalysts lose activity after 3 reuse cycles.

GRADO DE SECADO Y EFICIENCIA TÉRMICA DE UN SECADOR DE TORNILLO TRANSPORTADOR DRYING

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MANUEL ALEJANDRO TRIANA

2011-01-01

Full Text Available En un secador tipo tornillo transportador (SCD, se evaluó el grado de secado y la eficiencia térmica en el secado de acetato de calcio dihidratado. El SCD tiene 8.66 m de longitud y 0.17 m de diámetro del tornillo. Las variables del diseño factorial (niveles mixtos 2x3 2 fueron: la velocidad rotacional del tornillo (N en dos niveles, la temperatura (T del sólido alimentado en tres niveles y el flujo de alimentación (C en tres niveles. Durante los experimentos la humedad inicial del sólido estuvo entre 5070%, obteniéndose grados de secado hasta del 14 % y eficiencias térmicas hasta del 88%. A partir de las superficies de respuesta de los anovas obtenidos en StatGraphics 5.1, se realizó la optimización simultánea de las dos variables de respuesta. Usando el concepto de diseño desbalanceado se encontró el óptimo global (45 ºC, 8 L/min y 3 rpm, que coincide con el óptimo observado.

Simulación matemática y optimización del secado de productos agropecuarios con aire natural y energía solar

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Jorge H. Domínguez

1983-05-01

Full Text Available En este trabajo se discuten las principales características de los sistemas de secado de productos agropecuarios con aire natural y energía solar y se presenta un programa de computador con el cual es posible simular, simultáneamente, la variación meteorológica, el proceso de secado y el proceso de deterioración de productos agropecuarios y optimizar el diseño de sistemas de secado solar y natural. EI programa constituye una herramienta básica que forma parte de una metodología de trabajo desarrollada por los autores para el estudio y evaluación desde el punto de vista técnico del potencial de secado con aire natural y energía solar de regiones tropicales.

Secado de lúcuma (Pouteria obovata) empleando la técnica de Ventana RefractanteTM

OpenAIRE

Diego Gamboa; Deiner Ibáñez; Marcela Meléndez; Edgar Paredes; Raúl Siche

2014-01-01

La lúcuma es una fruta que experimenta una tendencia creciente a nivel comercial en forma de harina para su empleo en la industria alimentaria. Este estudio tuvo como objetivo obtener harina de lúcuma utilizando el método de secado por ventana refractante y evaluar el efecto del espesor de la pulpa de lúcuma y el tiempo de secado en la humedad y el color de la harina. Fue utilizado un Diseño Compuesto Central Rotable (DCCR) con el tiempo entre 10 y 50 min y el espesor entre 1 y 3 mm. Se emple...

Evaluación de un secadero solar tendalero túnel: estudio de secado de manzanas.

OpenAIRE

Iriarte, Adolfo Antonio; Bistoni, Silvia Noemi; Garcia, Victor Orlando; Luque, V.

2015-01-01

En la selección de un secadero solar se debe tener en cuenta las características del producto a secar, la ubicación geográfica del emprendimiento y el factor económico. A nivel nacional no existe una norma para evaluar la performance de un sistema de secado. En el presente trabajo se evalúa un secadero solar tipo túnel con convección forzada Está formado por dos partes: un colector solar y a continuación la cámara de secado. El producto utilizado fue manzana tipo comercial (61,7 kg), cortad...

EFECTO DE LA TEMPERATURA DE SECADO SOBRE EL GRADO Y LA VARIABILIDAD ESPACIAL DE LA REPELENCIA AL AGUA EN ANDISOLES DE ANTIOQUIA, COLOMBIA DRYING TEMPERATURE, PERSISTENCE AND SPATIAL VARIABILITY OF WATER REPELLENCY IN ANDISOLS OF ANTIOQUIA, COLOMBIA

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Daniel Francisco Jaramillo Jaramillo

2007-12-01

Full Text Available En la cuenca hidrográfica de la quebrada Piedras Blancas, Oriente Antioqueño - Colombia, se ubicaron dos sitios con diferente cobertura vegetal: uno con una plantación de Pinus patula (pino y el otro, con cobertura natural. En cada sitio se demarcaron dos transectos con diferente dirección: uno N-S y el otro E-O. Sobre cada transecto se hizo un muestreo intensivo del suelo, a cuatro profundidades y en dos épocas diferentes: una seca y otra húmeda, para evaluar la persistencia de la repelencia al agua real y la respuesta de la repelencia al agua al secado de las muestras a diferentes temperaturas en ambas coberturas, épocas y direcciones. La evaluación de la persistencia se hizo con el método WDPT (Water Drop Penetration Time en condiciones de campo y en suelos secados a temperaturas de 15, 20, 25, 30, 35 y 105°C. Se observó que al incrementar la temperatura de secado, se incrementó la repelencia al agua y el volumen de suelo afectado por la hidrofobicidad. Esta situación, aunque se presenta en ambas coberturas, ocurre con mayor intensidad en los suelos ubicados bajo plantaciones de Pinus patula. Se encontró una anisotropía marcada en la repelencia al agua, la cual presentó una tendencia general a desarrollar mayor grado de hidrofobicidad en los transectos ubicados en dirección E-O. En todos los transectos estudiados se detectó una amplia variabilidad espacial, de rango corto, en la repelencia al agua, así como una distribución en parches del fenómeno y la generación de vías de flujo preferencial para la entrada y circulación de agua en el suelo.In Piedras Blancas watershed, Oriente Antioqueño - Colombia , two sites with different vegetative cover were located: one with a plantation of Pinus patula (pine and the other one with natural covering. In each site two transects with different direction were defined: one N-S and the other one E-O. On each transect an intensive sampling of soil was made to four depths and in two

Efecto de las condiciones de secado sobre el endurecimiento de los granos de caraota (Phaseolus vulgaris pretratados con vapor

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María Virginia Mujica

2017-12-01

Full Text Available El endurecimiento de los granos de caraota (Phaseolus vulgaris generado por el almacenamiento en condiciones de alta temperatura y humedad relativa representa una limitante importante para su consumo. El objetivo del presente trabajo fue evaluar el efecto de un tratamiento con vapor y luego secado a los granos de P. vulgaris recién cosechados en la prevención de su endurecimiento. Inicialmente, se construyeron las curvas de secado a 40; 47,5 y 55 ºC. Seguidamente, los granos se trataron con vapor por 8 min 20 s y se sometieron a un proceso de secado, bajo un diseño central compuesto cuyos factores fueron la temperatura del aire (40 y 55 ºC y el tiempo de secado (4 y 8 h. La muestra secada de cada tratamiento se dividió en 3 lotes, el primero se analizó de inmediato y los otros se almacenaron por 5 semanas bajo 2 condiciones distintas 5 ºC/34 % HR y 37 ºC/75 % HR. Las determinaciones realizadas fueron humedad, capacidad de imbibición, tiempo de cocción y actividad de la peroxidasa soluble. El tiempo de secado fue de 6,5; 5 y 2,5 h a 40; 47,5 y 55 ºC, respectivamente, para alcanzar una humedad de 13 % (b.s.. El coeficiente de difusión resultó igual a 3,40x10-9; 3,52x10-9 y 3,87x10-9 m2/s, a 40, 47,5 y 55 ºC, respectivamente. El valor de la energía de activación fue de 7,33 kJ/mol. La aplicación de vapor y posterior secado de los granos no previno su endurecimiento, y este no dependió de la actividad de la peroxidasa soluble. Por lo que se puede inferir que los compuestos fenólicos y la enzima peroxidasa no son los únicos implicados en el mecanismo de endurecimiento de los granos de P. vulgaris.

Secado de trozos de yuca por convección natural en los valles de los ríos Cauca y Magdalena

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Alfonso Parra Coronado

1992-09-01

Full Text Available En este artículo se presentan los resultados obtenidos en la evaluación del potencial de secado de yuca en trozos por convección natural en los Valles de los ríos Cauca y Magdalena, utilizando la metodología desarrollada en el Departamento de Ingeniería Agrícola de la Universidad Nacional de Colombia sede Santafé de Bogotá, D.C., por Domínguez J. y Parra A. (1982, dentro de la línea de investigación "Secado y almacenamiento de Productos Agrícolas". La metodología se basa en la técnica de simulación matemática, mediante la cual es posible predecir simultáneamente, la variación meteorológica, el proceso de secado y el proceso de deterioración del producto, con el fin de optimizar el manejo y funcionamiento de sistemas de secado solar y natural. El modelo de simulación se compone de: el modelo de secado natural desarrollado por Roa (1974, el modelo de deterioro desarrollado por Ospina (1979 y de una rutina de interpolación polinomial que permite obtener la carga máxima de yuca (Kg/m2 que se puede secar sin que se deteriore más del 15%.

Análisis de la influencia del régimen de temperatura en el secado del mineral laterítico

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Elis Efraín-Guzmán

2003-03-01

Full Text Available En las empresas cubanas del níquel con tecnología carbonato amoniacal (CAROM, el proceso de secado no logra los valores óptimos de humedad que garantizan la molienda. En este trabajo se determina la influencia de la humedad de equilibrio, la constante de secado y el coeficiente de transferencia de masa, durante el secado del mineral laterítico a escala de laboratorio. Se obtiene la correlación y regresión de las variables antes mencionadas en función de la temperatura y el contenido de humedad del mineral. Se confirmó experimentalmente que para un rango de temperatura entre 80 y 120 ºC, la de humedad de equilibrio del mineral laterítico se encuentra entre 0,0217 y 0,039 g /g, la constante de secado entre 0,0198 y 0,0077 1/min., y el coeficiente de transferencia de masa entre 0,0044 y 0,0116 g / m2 .min. Se concluye que el exceso de humedad en el mineral que sale de los secadores no está relacionado con el régimen de temperatura usado en el proceso

Desarrollo de un horno solar para el secado de plantas y vegetales usando control difuso

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Oscar G. Ibarra Manzano

2012-05-01

Full Text Available Recientemente, el aprovechamiento de la energía solar en el deshidratado de productos agrícolas se ha vuelto cada día más común debido a los altos rendimientos en los productos post-cosecha. La inversión en tecnologías propias para contribuir con los productores del sector agroalimentario es un factor importante para el desarrollo de las cadenas produc­tivas de nuestro país. En este trabajo se presenta el desarrollo de un horno solar para el secado de plantas y vegetales utilizando control difuso. Este es un sistema térmicamente controlado que permite disminuir el tiempo de secado de varios días a unas horas. Se reali­zaron pruebas de secado usando flor de jamaica, en las cuales se pudo disminuir el tiempo de secado de cuatro días a aproximadamente 5 h. Se presentan tanto la parte de diseño conceptual, como resultados experimentales del mismo. Los resultados obtenidos permiten ver la viabilidad del diseño propuesto.Recently, the use of solar energy in the dehydration of agricultural products is becomingmore common as high yields in the post-harvest products. Investment in technologies forcontributing to the producers of food products is an important factor for the development ofthe productive chains of our country. This paper presents the development of a solar oven fordrying plants and vegetables using fuzzy control. This is a heat-controlled system that allowsdecreasing the drying time from several days to hours. Drying tests were conducted usingjamaica flower, which could decrease the drying time from four days to about 5 h. We presentboth the conceptual design of the experimental results. The results obtained allow us to seethe feasibility of the proposed design.

Recobrimento da liga Ti-6Al-4V com hidroxiapatita pelo método sol-gel e sua aplicação a hastes femorais não-cimentadas Coating of Ti-6Al-4V alloy with hydroxyapatite by using sol-gel method and its application to non-cemented femoral stem

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E. P. Avés

2008-12-01

Full Text Available O recobrimento de ligas metálicas com cerâmicas bioativas visa acelerar a formação óssea ao redor do implante, contribuindo para a sua estabilização. Neste trabalho estudou-se a fase cerâmica de hidroxiapatita depositada pelo processo sol-gel em chapas da liga metálica Ti-6Al-4V. A camada de recobrimento foi caracterizada por microscopia eletrônica de varredura, por difração de raios X e sua adesão ao substrato foi avaliada pelo teste de cisalhamento O teste de citocompatibilidade mostrou que o processo de recobrimento por sol-gel não promoveu morte celular significativamente maior que o controle (p > 0,05. Além disso, hastes femorais removidas de pacientes (explantes foram adequadamente recobertas utilizando-se o processo sol-gel.The coating of metallic alloys with bioactive ceramics aims to accelerate bone formation around the implant, contributing to its fixation. In this paper, the deposition of hydroxyapatite ceramic on Ti-6Al-4V alloy sheets by the sol-gel method was studied. The coating layer was characterized by scanning electron microscopy, X-ray diffraction and its adhesion to substrate was evaluated by shear testing. The citocompatibility test shows that the sol-gel coating did not provoke the cell death significantly higher than the control (p > 0.05. Moreover, femoral stems removed from patient (explants were adequately coated using the sol-gel process.

Production of porous titanate microspheres by spray-drying of sols

International Nuclear Information System (INIS)

Sizgek, E.; Bartlett, J.R.; Woolfrey, J.L.

1992-01-01

Porous, multi-component titanate microspheres (20 to 50 μm in diameter) have been produced on a 10 kg scale by spray-drying a precursor sol containing titania, zirconia and alumina, and calcining the resulting powders at 723 K. The mixed TiO 2 /ZrO 2 sols were produced by hydrolysing tetraisopropyltitanate and peptising the hydrolysate slurry with zirconyl nitrate solution. TiO 2 /ZrO 2 sols with oxide concentrations in excess of 900 g dm -3 were produced. These sols were subsequently mixed with dispersible δ-Al 2 O 3 to produce well-dispersed TiO 2 /ZrO 2 /Al 2 O 3 (TZA) sols. The rheology and degree of aggregation of the multi-component sols were controlled by the addition of Al(NO 3 ) 3 solution. At relatively low electrolyte concentrations, the sols exhibited Newtonian behaviour, and the viscosity increased with increasing addition of electrolyte. However, at higher electrolyte concentrations, the colloidal dispersions exhibited shear-thinning behaviour. Hollow spheres were produced by spray-drying well-dispersed sols. In contrast, 'solid' spheres were produced by using dilute Al(NO 3 ) 3 to produce partially-aggregated TZA sols, prior to spray-drying. Calcined microspheres produced from partially-aggregated sols had total porosities of ∼ 50 %, with average pore diameters of ∼ 8 nm. These particles exhibited a high sorption capacity for simulated High Level Nuclear Waste

Incremento de disolución de un derivado del furano mediante la técnica de secado por atomización

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Antonio Iraizoz Barrios

2012-06-01

Full Text Available Objetivo: incrementar la solubilidad en agua del 2-bromo-5-(2-bromo-2-nitrovinyl-furano (G1, un ingrediente farmacéuticamente activo sintetizado por el Centro de Bioactivos Químicos de la Universidad Central de Las Villas, con potente acción bactericida y fungicida, mediante la elaboración de macropartículas de dispersiones sólidas utilizando un proceso de secado por atomización. Métodos: se realizó un ensayo preliminar de secado por atomización de la suspensión de G1, compuesta por: 10 g de G1, 1 g de Aerosil (Aerosil®, Degusa, Bélgica, 1 g de laurilsulfato de sodio y 100 mL de agua. La atomización se efectuó en un equipo de laboratorio (Buchi Mini Dryer spray a 90 ºC. La dispersión sólida obtenida fue caracterizada físico-químicamente mediante difracción de rayos X, granulometría láser por el método de difracción angular, calorimetría diferencial de barrido, microscopia electrónica de barrido y espectrofotometría de absorción infraroja. Resultados: las partículas obtenidas presentaron un pequeño tamaño, forma esférica y un incremento de la cristalinidad del G-1; no se encontraron interacciones entre los componentes de la dispersión ni presencia de productos de degradación, y la solubilidad del G-1 en agua resultó notablemente incrementada. Conclusiones: el producto obtenido por la técnica de secado por atomización incrementó apreciablemente la solubilidad del G1 sin afectar los grupos funcionales, responsables de la actividad terapéutica que se le reportan al ingrediente activo estudiado. Estos alentadores resultados sugieren la necesidad de continuar estudios para la optimización del proceso y realizar al producto obtenido ensayos de estabilidad con el objetivo de su futura inclusión en formas farmacéuticas de dosificación.

Energy optimization in industrial drying systems; Optimizacion energetica en sistemas de secado industrial

Energy Technology Data Exchange (ETDEWEB)

Alarcon, Daniel; Ambriz, Juan Jose; Romero Paredes, Hernando [Universidad Autonoma Metropolitana-Iztapalapa, Mexico, D. F. (Mexico)

1994-12-31

The drying of products -meaning the extraction of water or excess humidity down to adequate levels for its conservation and final presentation- demands a large amount of energy, mainly from fuels of fossil origin. Nevertheless, from the standpoint of the energy efficiency, the burning of fuels at very high temperature for using them at a very low temperature, represents an astonishing energy waste, which can be clearly established by means of an energy and exergy balance of these drying installations. In this study the methodology for the energy analysis for industrial drying systems is presented and it is applied to different practical cases. The efficiency of the entire system is evaluated and the losses for each concept, in order to obtain the potential energy saving. [Espanol] El secado de productos, entendido como la extraccion de agua o humedad en exceso, hasta niveles adecuados para su conservacion o presentacion final, demanda una gran cantidad de energeticos, principalmente de origen fosil. No obstante, desde el punto de vista de la eficiencia energetica, el quemar combustible a muy alta temperatura para emplearlos a una muy baja, representa un dispendio energetico impresionante, lo cual puede ser claramente establecido mediante el balance energetico y exergetico de dichas instalaciones de secado. En el presente estudio se presenta la metodologia de analisis energetico de sistemas industriales de secado y se aplica a distintos casos practicos. Se evalua la eficiencia total del sistema y las perdidas por cada concepto con la finalidad de obtener los potenciales de ahorro de energia.

Modelación matemática del área de exposición y del volumen de las pilas de menas lateríticas expuestas a secado solar natural

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Yoalbys Retirado-Mediaceja

2011-10-01

Full Text Available Las menas lateríticas cubanas se exponen, en forma de pilas, a la radiación solar y la convección del aire para reducirles el contenido de humedad mediante la implementación del proceso de secado solar natural. La confección de las pilas de minerales se basa en criterios empíricos y, en consecuencia, no se conoce el área de exposición de las mismas y el volumen de mineral expuesto al secado. En este artículo se establecen los modelos matemáticos que permiten calcular, de forma precisa, la longitud de la superficie lateral, la altura, el área de exposición y el volumen de las pilas de mineral, en función de las dimensiones de la superficie horizontal disponible para el secado y de dos propiedades del material: la granulometría y la humedad. Las ecuaciones matemáticas establecidas caracterizan a las pilas con simetría axial y secciones transversales semi-elípticas, hiperbólicas, parabólicas y triangulares. Se aplicaron los modelos obtenidos a un caso de estudio para una superficie horizontal disponible de 40 m de largo y 5 m de ancho, considerando los valores medios de los ángulos de reposo maximal y tangencial de las menas lateríticas cubanas.

EFECTO DE LAS CONDICIONES DE SECADO SOBRE LA CINÉTICA DE DESHIDRATACIÓN DE LAS HOJAS DE MORERA (Morus alba

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Mar\\u00EDa Lourdes Pineda-Castro

2009-01-01

Full Text Available El objetivo del presente trabajo fue determinar las cinéticas de deshidratación de la morera bajo diferentes condiciones de temperatura, velocidad y humedad del aire, entre junio y diciembre del 2006, en Costa Ri ca. Forraje de morera (Morus alba de 75 días fue empleado como sustrato. Se evaluó la cinética de deshidratación en un secador convectivo de resistencias eléctricas de bandeja única con diámetro de 0,22 m y carga de 122 ± 1 g hasta una humedad del 5 %. La evaluación se realizó para tres temperaturas de secado (60 °C, 75 °C y 90 °C, dos velocidades de aire (1,0 y 2,5 m/s y dos humedades del aire (12 g/kg aire seco y 45 g/kg aire seco, para un total de 12 tratamie ntos trip licados. Las curvas de secado correspondie ntes se estudia ron según el modelo de decaimiento exponencial de Newton. Se obtuvieron gráficos de velocidad de secado en función del tiempo y la humedad. Las cinéticas de deshidratación presentaron la curva típica del modelo de Newton, con altos coeficientes de correlación. Existió un efecto triple significativo (p<0,05 entre la temperatura, la velocidad y la humedad del aire sobre el tiempo de secado del sustrato; la variable más influyente fue la temperatura, seguida de la velocidad y por último la humedad del aire. El aumento de cualquie ra de estas varia bles implicó una disminución del tiempo de secado. El efecto de la temperatura sobre éste fue más pronuncia do a una velocidad del aire de 1 m/s.

Estrategia de comunicación digital aplicado a empresa de producto artesanal: Al Sol, a mano

OpenAIRE

GARCÍA ÁLVAREZ, CLARA

2015-01-01

El objetivo principal es promocionar la tienda y marca de Al Sol, a mano en la red y en el área de Valencia, ciudad donde se ubica. Cualquier marca, debe de encontrarse en Internet. Gracias al comercio electrónico, las redes sociales, páginas web o blogs estas pequeñas empresas pueden crecer sin un gran gasto económico. Estas plataformas y buscadores son una forma sencilla de estar presente y el mejor escaparate para darse a conocer y llegar a un gran público. Igualmente en la ...

Secado de primeras materias cerámicas por atomización

OpenAIRE

Editorial, Equipo

2016-01-01

El secado por atomización consiste en inyectar una suspensión de arcilla, de pasta o de cualquier otra materia, en aire seco y caliente. El agua se evapora y las partículas, totalmente secas o con el contenido deseado en humedad, se separan de la corriente de aire. Este proceso es muy adecuado para la preparación de pastas para prensado en seco.

Efecto Térmico del Secado por Aspersión sobre los Metabolitos Antioxidantes de la Curuba Larga (Passiflora mollisima baley)

OpenAIRE

Zapata, Karol; Rojano, Benjamín A; Cortes, Farid B

2015-01-01

En este estudio se evalúo la capacidad antioxidante y el contenido de polifenoles del fruto de Curuba larga antes y después del secado por aspersión. El elevado contenido de agua hace de los alimentos hortofrutícolas productos perecederos y de poca vida en anaquel. Métodos de secado garantizan la estabilidad microbiológica de la fruta, aunque inducen pérdidas nutracéuticas en el producto final debido a las altas temperaturas utilizadas. Los resultados revelaron que existe un alto porcentaje d...

Polymeric-silica-based sols for membrane modification applications: sol-gel synthesis and characterization with SAXS

NARCIS (Netherlands)

de Lange, Rob; de Lange, R.S.A.; Hekkink, J.H.A.; Hekkink, J.H.A.; Keizer, Klaas; Burggraaf, Anthonie; Burggraaf, A.J.

1995-01-01

Polymeric SiO2 and binary SiO2/TiO2, SiO2/ZrO2 and SiO2/Al2O3 sols, for ceramic membrane modification applications, have been prepared by acid-catalyzed hydrolysis and condensation of alkoxides in alcohol. The sols were characterized with small angle X-ray scattering, using synchrotron radiation.

Efecto del secado de las muestras sobre la extracción selectiva de Fe y A1 activos en Andisoles del norte de la cordillera central Colombiana.

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Jaramillo J. Daniel F.

2000-12-01

Full Text Available Muestras secadas al aire y sin secar de cinco perfiles de Andisoles del norte de la cordillera central colombiana fueron sometidas a extracción con oxalato ácido de amonio y con pirofosfato de sodio. En los extractos de oxalato se determinaron A1, Fe y Si y en los de pirofosfato A1 y Fe. El secado de las muestras redujo significativamente al 95% la cantidad de A1 y de Fe extraída con oxalato ácido, dificultando la clasificación de los suelos en el orden Andisol utilizando los parámetros de la taxonomía del USDA.

Aplicación de la energía solar en el secado de granos

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Andrés Bello G.

1983-01-01

Full Text Available En este artículo se presenta la síntesis del procedimiento y los resultados obtenidos en un prototipo de colector almacenador solar para secado de granos, como parte de las investigaciones que está desarrollando el Departamento de Ingeniería Mecánica.

Secado del orujo en lecho fluidizado-móvil

OpenAIRE

Torrecilla Velasco, José Santiago

2000-01-01

El objetivo fundamental de la presente Tesis Doctoral es validar y optimar un secadero basado en la combinación de dos tipos de contactores como son el lecho fluidizado y el móvil. Para ello se han realizado experimentos de secado de orujo empleando primero contactores por separado (fijo, móvil y fluidizado) se ha estudiado la combinación de los lechos fluidizado y móvil. Desde el punto de vista económico y de calidad del orujo seco se ha demostrado que el secadero más adecuado para realizar ...

EVALUACIÓN DEL EFECTO DE LA TEMPERATURA EN EL SECADO DE POLEN APÍCOLA PROCEDENTE DE DOS ZONAS DE CUNDINAMARCA

OpenAIRE

JOHANNA PATRICIA BARAJAS-ORTIZ; TELMO MARTÍNEZ; EDUARDO RODRÍGUEZ-SANDOVAL

2011-01-01

En este estudio se evalúa la influencia de la temperatura de secado (35°C y 45°C) y el origen del producto (la Calera y Zipaquirá) sobre las características físicas, químicas, y nutricionales del polen seco. Los métodos utilizados para determinar la influencia de los tratamientos son: Caracterización fisicoquímica, actividad de agua, índice de solubilidad, tamaño de partícula, contenido de vitamina C y carotenos. Los resultados confirman que el secado de polen a una temperatura de 45ºC es el ...

Electrical stability of Al-doped ZnO transparent electrode prepared by sol-gel method

International Nuclear Information System (INIS)

Tabassum, Samia; Yamasue, Eiji; Okumura, Hideyuki; Ishihara, Keiichi N.

2016-01-01

Highlights: • Al-doped ZnO thin film was deposited by sol-gel method in different annealing temperature and duration. • We examined the environmental stability in ambient and damp heat condition. • We investigated chemical state of thin film. • Better stability was observed in the film annealed at high temperature (600 °C) along with longer duration (120 min). • An ultrathin aluminum oxide layer formation was predicted by XPS measurement which protects further oxidation and improves stability. - Abstract: Al-doped zinc oxide (AZO) thin films have been considered as a promising alternative to tin doped indium oxide (ITO), which is currently used in various optoelectronic applications. However, the environmental stability of AZO film is not satisfactory, in that the resistivity is significantly increases in air. Here, we investigate the resistivity stability of AZO thin films prepared by sol-gel method using various annealing temperatures and durations. The degradation of resistivity property was observed for AZO films stored in ambient or damp heat environment, where the degradation rate was influenced by annealing temperature. A significant improvement of electrical stability was attained in AZO films that were prepared at high annealing temperature. The films, which showed the highest and the lowest increasing rate of resistivity, were further characterized in detail to shed light on the possible mechanisms explaining the improved stability through crystallinity, surface morphology and elemental state of the thin film.

Electrical stability of Al-doped ZnO transparent electrode prepared by sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Tabassum, Samia, E-mail: shawon14@gmail.com; Yamasue, Eiji; Okumura, Hideyuki; Ishihara, Keiichi N.

2016-07-30

Highlights: • Al-doped ZnO thin film was deposited by sol-gel method in different annealing temperature and duration. • We examined the environmental stability in ambient and damp heat condition. • We investigated chemical state of thin film. • Better stability was observed in the film annealed at high temperature (600 °C) along with longer duration (120 min). • An ultrathin aluminum oxide layer formation was predicted by XPS measurement which protects further oxidation and improves stability. - Abstract: Al-doped zinc oxide (AZO) thin films have been considered as a promising alternative to tin doped indium oxide (ITO), which is currently used in various optoelectronic applications. However, the environmental stability of AZO film is not satisfactory, in that the resistivity is significantly increases in air. Here, we investigate the resistivity stability of AZO thin films prepared by sol-gel method using various annealing temperatures and durations. The degradation of resistivity property was observed for AZO films stored in ambient or damp heat environment, where the degradation rate was influenced by annealing temperature. A significant improvement of electrical stability was attained in AZO films that were prepared at high annealing temperature. The films, which showed the highest and the lowest increasing rate of resistivity, were further characterized in detail to shed light on the possible mechanisms explaining the improved stability through crystallinity, surface morphology and elemental state of the thin film.

Aplicación de modelos matemáticos al proceso de secado asistido por infrarrojos de descartes de limón (Citrus limon (L. Burm. F. Cv. Genova

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Luis Puente-Díaz

2013-01-01

Full Text Available Los desechos agroindustriales son uno de los principales problemas ambientales a nivel mundial. Debido a las altas exigencias de calidad, la comercialización de limones de exportación genera grandes cantidades de desechos. Los descartes de limón contienen fibra, pectina, potasio, calcio y vitamina C. Por lo tanto, es importante desarrollar alternativas de procesamiento de estos sub-productos para agregarles valor y aumentar su vida útil. El objetivo de la presente investigación fue la aplicación del secado asistido por infrarrojos, como tecnología emergente, para estudiar el efecto de la temperatura de proceso sobre las cinéticas de secado de descartes de limón a 30, 40 y 50°C. Se utilizaron seis modelos matemáticos de capa fina encontrados en literatura para representar la cinética experimental. Basándose en análisis estadístico, el modelo Logarítmico presentó el mejor ajuste. Los valores de la difusividad efectiva del agua se estimaron en el rango de 9.45× 10-10 – 3.71× 10-9 m/s2. El valor de la energía de activación fue 55.90 kJ/mol.

Proceso artesanal de extracción, manejo y secado de las fibras naturales de banano (Musa paradisiaca en la Parroquia El Retiro de la Provincia de El Oro

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Linda Maldonado

2016-06-01

Full Text Available Ecuador es considerado un país bananero. En muchas de sus provincias existen grandes plantaciones de banano y que se aprovecha solo el fruto. Se desechan su pseudotallo y otras partes, que pocas veces se emplean como abono. El objetivo del  proyecto es darle un valor agregado a este  residuo, aprovechando toda la fibra natural que posee para utilizarla en la obtención de panelería y enchapes del tipo Fibra de densidad media, conocidos por su sigla en inglés MDF. El presente artículo tiene como propósito dar a conocer el proceso de extracción de las fibras de una forma absolutamente artesanal que se inicia a partir de la selección y corte del pseudotallo, su  desvainado y la separación  de cada uno de los tipos de fibras. Estas se clasifican en suaves, duras  y la denominada  malla. Una vez obtenidas las fibras, se procede a secarlas, se observan detenidamente y se tiene en cuenta las horas de exposición al sol, y las que permanecen a la sombra, prestando  especial atención  al color que adquieren  de acuerdo con la radiación solar, y el tiempo de cortado el pseudotallo. Se consideró aplicarle color a la fibra y se tiñó mediante un proceso de cocción, durante el cual se le agrega  tinte  vegetal  de color turquesa. Posteriormente concluimos que  para el objeto de nuestro estudio  no es necesario  que tengan colores  artificiales,  pero sí sería ideal, aumentar  la intensidad de su color natural después del secado, eso realzaría la textura de los paneles y enchapes que se desean obtener.

Empleo de metodos numericos para el ajuste de los coeficientes de difusividad (D) y convectivo de transferencia de masa (hm) en el secado de alimentos

OpenAIRE

Arranz Saiz, Francisco Javier; Correa Hernando, Eva Cristina; Jiménez Ariza, Heidi Tatiana; Diezma Iglesias, Belen; Garcia-Herrero, Javier; Robla Villalba, José Ignacio; Barreiro Elorza, Pilar

2011-01-01

Los modelos matemáticos de transferencia de humedad desde el alimento al medio circundante durante el proceso de secado dependen de dos parámetros: coeficiente de difusividad efectiva D y coeficiente convectivo de transferencia de masa hm, cuya determinación experimental se basa en la consideración de un sistema difusivo sencillo de solución analítica bien conocida. Para el caso, que aquí nos ocupa, de difusión monodimensional en una lámina infinita de grosor 2l, la solución analítica de ...

Drying of mango pulp in a dryer of laboratory tunnel type; Secado de pulpa de mango en un secador de laboratorio tipo tunel

Energy Technology Data Exchange (ETDEWEB)

Pacheco Resendiz, Oscar; Chagoyan Serrano, Jose; Flores I, Alfredo; Rodriguez M, Jose A [Universidad Autonoma de Baja California Sur (Mexico)

2000-07-01

The result of four tests of drying of mango pulp Kent are presented, which were carried out in a dryer of the tunnel type in constant conditions of temperature, speed and absolute humidity of the air. The temperatures at which the tests were conducted were 35, 40, 45 and 50 Celsius degrees. The average speed of the drying air was 2.35 m/s. For the four tests the drying variables were measured for the purpose of controlling the process. The tests were suspended after 10 hours. The initial and final moisture contents of the samples on a wet weight basis for the test at 35 were 87.04% and 58.94% for that at 40 were 87.42% and 17.25%, for that at 45 were 87.55% and 13.29%, and for that at 50 were 87.43% and 48%. The graphs of the evolution of moisture content of the samples dried under the specified conditions are compared. [Spanish] Se presentan los resultados de cuatro pruebas de secado de pulpa de mango Kent, las cuales se realizaron en un secador tipo tunel en condiciones constantes de temperatura, velocidad y humedad absoluta del aire. Las temperaturas empleadas fueron 35, 40, 45 y 50 grados Celsius y la velocidad del aire de secado fue de 2.35 m/s. Para las cuatro pruebas se midieron las variables de secado mencionadas con el fin de controlar el proceso. Las pruebas se suspendieron al cumplirse 10 h. Las humedades inicial y final base humeda de las muestras para la prueba de 35 fueron 87.04% y 58.94%, para la de 40 fueron 87.42% y 17.25% y para la de 45 fueron de 87.55% y 13.29% y para la de 50 fueron de 87.43% y 48%. Se comparan entre si las graficas de la evolucion del contenido de humedad de las muestras que se secaron a las condiciones ya mencionadas.

PROPIEDADES TÉCNICO-FUNCIONALES DE LA FIBRA DIETARIA DE CÁSCARAS DE MANGO VARIEDADHILACHA (Mangifera indica L.): EFECTO DEL SECADO POR CONVECCIÓN

OpenAIRE

GUSTAVO ADOLFO HINCAPIÉ LL.; DIANA CAROLINA VÁSQUEZ O; VALERIA SOFÍA GALICIA M; CARLOS AUGUSTO HINCAPIÉ LL.

2014-01-01

Un subproducto de la obtención del jugo de mango es su cáscara; la cual contiene niveles considerables de fibra dietaria que podrían ser utilizados en la elaboración de productos alimenticios, sin embargo, actualmente no es muy aprovechado. El proceso de secado prolonga la vida útil de la cascara y permite que pueda ser adicionada a otros alimentos. En este estudio, se caracterizó fisicoquímicamente la Cáscara de Mango Hilacha (CMH) y se evaluó el efecto de cinco temperaturas de secado sobre ...

Sol, Tierra y Luna. Movimientos relativos y sus consecuencias

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Sebastián Cardenete García

2011-01-01

Full Text Available Cuando se pregunta a los estudiantes por la causa de las estaciones suelen responder: "en verano estamos más próximos al Sol y en invierno estamos más lejos del Sol". La persistencia de esta idea y el hecho de su generalización entre los estudiantes y muchos adultos me ha inducido a escribir este artículo, en el cual se trata de explicar, de una forma clara y simple, el motivo de este y otros fenómenos debidos al movimiento de la Luna alrededor de la Tierra y de ésta alrededor del Sol.

Evaluación del efecto de la temperatura en el secado de polen apícola procedente de dos zonas de cundinamarca

OpenAIRE

BARAJAS-ORTIZ, JOHANNA PATRICIA; MARTÍNEZ, TELMO; RODRÍGUEZ-SANDOVAL, EDUARDO

2011-01-01

En este estudio se evalúa la influencia de la temperatura de secado (35°C y 45°C) y el origen del producto (la Calera y Zipaquirá) sobre las características físicas, químicas, y nutricionales del polen seco. Los métodos utilizados para determinar la influencia de los tratamientos son: Caracterización fisicoquímica, actividad de agua, índice de solubilidad, tamaño de partícula, contenido de vitamina C y carotenos. Los resultados confirman que el secado de polen a una temperatura de 45ºC es el ...

Synthesis by Sol-gel and characterization of catalysts Ag/Al2O3-CeO2

International Nuclear Information System (INIS)

Zayas, M.L.; Perez H, R.; Rubio, E.; Velasco, A.

2004-01-01

Aluminia, cerium and mixed oxides Al 2 O 3 -CeO 2 with different relationship Al/Ce (0.75, 0.50 and 0.25) were prepared by sol-gel and used as support for the Ag. The samples were characterized by XRD, DRIFT, TPR and adsorption of N 2 to temperature of liquid nitrogen. The surface area BET showed that the materials that contain aluminia present near values among them. XRD allowed to identify to the cerianite in the oxides that whose support contains cerium and to the α-aluminia. A mixture of phases was observed in the aluminia. Vibration bands attributed to the bond Al-O and Ce-O were observed by DRIFT in the catalytic materials. TPR showed differences in the reducibility of the Ag precursor in the indicative catalysts of a different interaction with the support. (Author)

Fast wave power flow along SOL field lines in NSTX

Science.gov (United States)

Perkins, R. J.; Bell, R. E.; Diallo, A.; Gerhardt, S.; Hosea, J. C.; Jaworski, M. A.; Leblanc, B. P.; Kramer, G. J.; Phillips, C. K.; Roquemore, L.; Taylor, G.; Wilson, J. R.; Ahn, J.-W.; Gray, T. K.; Green, D. L.; McLean, A.; Maingi, R.; Ryan, P. M.; Jaeger, E. F.; Sabbagh, S.

2012-10-01

On NSTX, a major loss of high-harmonic fast wave (HHFW) power can occur along open field lines passing in front of the antenna over the width of the scrape-off layer (SOL). Up to 60% of the RF power can be lost and at least partially deposited in bright spirals on the divertor floor and ceiling [1,2]. The flow of HHFW power from the antenna region to the divertor is mostly aligned along the SOL magnetic field [3], which explains the pattern of heat deposition as measured with infrared (IR) cameras. By tracing field lines from the divertor back to the midplane, the IR data can be used to estimate the profile of HHFW power coupled to SOL field lines. We hypothesize that surface waves are being excited in the SOL, and these results should benchmark advanced simulations of the RF power deposition in the SOL (e.g., [4]). Minimizing this loss is critical optimal high-power long-pulse ICRF heating on ITER while guarding against excessive divertor erosion.[4pt] [1] J.C. Hosea et al., AIP Conf Proceedings 1187 (2009) 105. [0pt] [2] G. Taylor et al., Phys. Plasmas 17 (2010) 056114. [0pt] [3] R.J. Perkins et al., to appear in Phys. Rev. Lett. [0pt] [4] D.L. Green et al., Phys. Rev. Lett. 107 (2011) 145001.

Secado de lúcuma (Pouteria obovata empleando la técnica de Ventana RefractanteTM

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Diego Gamboa

2014-01-01

Full Text Available La lúcuma es una fruta que experimenta una tendencia creciente a nivel comercial en forma de harina para su empleo en la industria alimentaria. Este estudio tuvo como objetivo obtener harina de lúcuma utilizando el método de secado por ventana refractante y evaluar el efecto del espesor de la pulpa de lúcuma y el tiempo de secado en la humedad y el color de la harina. Fue utilizado un Diseño Compuesto Central Rotable (DCCR con el tiempo entre 10 y 50 min y el espesor entre 1 y 3 mm. Se empleó una temperatura fija de 95°C y lámina mylar (polietileno de tereftalato metalizado como película refractante de 0,1 mm. Se determinó que las condiciones ideales para obtener harina de lúcuma (9,8% de humedad con esta técnica se da cuando el espesor fue 1,3 mm y con un tiempo de 15 minutos; a estas condiciones la difusividad efectiva del agua es de 2,53E-7 m2/s.

Determinación de la condición fisiológica de la semilla de Capsicum spp y efecto del método de secado para su almacenamiento.

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Cardozo C. I.

2004-04-01

Full Text Available Semillas del género Capsicum se caracterizaron fisiológicamente. Basados en datos de viabilidad y germinación se estimó la tolerancia a la desecación y conservación por lo cual se estableció la condición ortodoxa de las semillas. Sin embargo, se destaca la importancia de la variable vigor, que permitió establecer diferencias entre las especies respecto de su longevidad y deducir que los contenidos de humedad de 10% y 7.5% y temperatura de 10°C admiten mayor capacidad de conservación. Los cuatro métodos de secado (secado artificial, sílica gel, sol y sombra y los dos sistemas de ambiente controlado no presentaron diferencias significativas en viabilidad. Se detectaron niveles moderados de latencia en las semillas que pudieron interferir en la interpretación de los resultados. Palabras claves: C. annuum, C. frutescens, C. baccatum, viabilidad, germinación. ABSTRACT Determination of physiological status of Capsicum spp seed and efect of the dry method for storage. Capsicum spp seeds was physiologycal characterizated. Based on data of viability and germination to estimate the tolerance to drying and conservation, the orthodox condition of the seeds could be established. Nevertheless, the importance of the variable vigor stands out, that allowed to establish differences between the species with respect to its longevity, It was settled down that 10 and 7.5% of humidity contents and temperature of 10°C allow greater capacity of conservation. The four methods of seed drying and the capacity of conservation under two different controlled environment systems were not significant differences. Moderate levels of the seed dormancy could be interfered the interpretation of the results. Keywords: C. annuum, C. frutescens, C. baccalum, viability, germination

Effect of Al and N on the toughness of heavy section steel plates

International Nuclear Information System (INIS)

Kikutake, Tetsuo; Tokunaga, Yoshikuni; Nakao, Hitoji; Ito, Kametaro; Takaishi, Shogo.

1988-01-01

The effect of Al and N on the notch toughness and tensile strength of heavy section pressure vessel steel plates is investigated. Notch toughness of steel A533B (Mn-Mo-Ni), which has mixed microstructure of ferrite and bainite, is drastically changed by the ratio of sol.N/sol.Al. With metallurgical observations, it is revealed that AlN morphology is influenced by the ratio of sol.N/sol.Al through the level of solute Al(C Al ). At the heat treatment of heavy section steel plate, AlN shows OSTWALD ripening and its speed depends upon C Al . When Al is added (Al ≥ 0.010%) in steel and sol.N/sol.Al ≤ 0.5, C Al remains low. This prevents AlN ripening, and brings fine austenite grain size and high toughness. On the other hand, when sol.N/sol.Al Al becomes high and this gives poor toughness through coarse AlN precipitates and coarse austenite grain. Therefore, controll of sol.N/sol.Al over 0.5 is favorable to keep high toughness in A533B steel. In steel A387-22 (Cr-Mo) which has full bainitic microstructure, too fine austenite grain brings about poor hardenability, and polygonal ferrite, which brings about both poor strength and tughness, appears in microstructure. Then sol.N/sol.Al < 0.5 is better to give high hardenability in steel A387-22. (author)

Slow Release of Plant Volatiles Using Sol-Gel Dispensers.

Science.gov (United States)

Bian, L; Sun, X L; Cai, X M; Chen, Z M

2014-12-01

The black citrus aphid, also known as the tea aphid, (Toxoptera aurantii Boyer) attacks economically important crops, including tea (Camellia sinensis (L.) O. Kuntze). In the current study, silica sol-gel formulations were screened to find one that could carry and release C. sinensis plant volatiles to lure black citrus aphids in a greenhouse. The common plant volatile trans-2-hexen-1-al was used as a model molecule to screen for suitable sol-gel formulations. A zNose (Electronic Sensor Technology, Newbury Park, CA) transportable gas chromatograph was used to continuously monitor the volatile emissions. A sol-gel formulation containing tetramethyl orthosilicate and methyltrimethoxysilane in an 8:2 (vol:vol) ratio was selected to develop a slow-release dispenser. The half-life of trans-2-hexen-1-al in the sol-gel dispenser increased slightly with the volume of this compound in the dispenser. Ten different volatiles were tested in the sol-gel dispenser. Alcohols of 6-10 carbons had the longest half-lives (3.01-3.77 d), while esters of 6-12 carbons had the shortest (1.53-2.28 d). Release of these volatiles from the dispensers could not be detected by the zNose after 16 d (cis-3-hexenyl acetate) to 26 d (3,7-dimethylocta-1,6-dien-3-ol). In greenhouse experiments, trans-2-hexen-1-al and cis-3-hexen-1-ol released from the sol-gel dispensers attracted aphids for ≍17 d, and release of these volatiles could not be detected by the zNose after ≍24 d. The sol-gel dispensers performed adequately for the slow release of plant volatiles to trap aphids in the greenhouse. © 2014 Entomological Society of America.

Cinética de secado de la yuca (Manihot esculenta Crantz variedad CORPOICA M-tai en función de la temperatura y de la velocidad de aire

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Jairo Salcedo Mendoza

2014-12-01

Full Text Available El secado de yuca (Manihot esculenta Crantz variedad CORPOICA M-tai, fue realizado en un secador de bandejas a escala de laboratorio. Muestras de yuca con espesor de 0,2cm y diámetro de 0,4cm fueron colocadas en el equipo en contacto directo con aire caliente, bajo distintas condiciones de operación. Se evaluó el efecto de la temperatura (35, 45 y 55ºC y la velocidad del aire (1,0, 2,0 y 3,0m/s sobre el tiempo de secado y la difusividad efectiva. Los resultados obtenidos indicaron que a una temperatura y flujo de aire de 55°C y 3,0 m/s respectivamente, el tiempo de secado fue de 4,5h, alcanzándose una humedad de 4,87%. Los datos derivados de las curvas de secado fueron ajustados a los modelos de Newton, el de Dos términos exponencial, el de Wang y Singh, el de Henderson y Pabis modificado y el Difusión aproximal. De acuerdo con los resultados el modelo matemático que describió mejor el comportamiento cinético de las curvas de secado fue el modelo Difusión aproximal con una regresión lineal (0,958 ≤ R2 ≤ 0,993. La difusividad efectiva (Df de la yuca varió entre 1,26 x 10-10 y 4,14 x 10-10m2/s y la energía de activación (Ea varió entre 33,66 a 16,16KJ /mol.

Studies of (3-mercaptopropyl)trimethoxylsilane and bis(trimethoxysilyl)ethane sol-gel coating on copper and aluminum.

Science.gov (United States)

Li, Ying-Sing; Lu, Weijie; Wang, Yu; Tran, Tuan

2009-09-01

Bis(trimethoxysilyl)ethane (BTMSE) and (3-mercaptopropyl)trimethoxysilane (MPTMS) have been used as precursors to prepare sol-gels and hybrid sol-gel under acidic condition. From the X-ray photoelectron spectroscopy data on MPTMS sol-gel coated aluminum and copper, it has been shown that the silane film is covalently bonded to Al surface through the interfacial condensation. There is no evidence of bonding interaction between the thiol group and the Cu. The recorded reflection adsorption IR (RAIR) spectrum has provided evidence that the coating BTMSE film covalently interacts with Al. Vibrational assignments have been suggested for pure BTMSE, BTMSE sol-gel, BTMSE xerogel, and BTMSE coated Al panel based on the group frequencies and the variation of frequencies with the sample treatment conditions. The progression of condensation reaction has been observed from the IR spectra of the BTMSE sol-gel and the sol-gel coated film after the treatments at different temperatures with different lengths of time. The corrosion protection of the sol-gel coated Al and Cu has been characterized in NaCl solutions by cyclic voltammetric, potentiodynamic polarization and impedance spectroscopy methods. All these electrochemical measurements indicate that the sol-gel coated metals have better corrosion protection than the corresponding uncoated metals.

Sol-gel derived zinc oxide films alloyed with cobalt and aluminium

International Nuclear Information System (INIS)

Sharma, Mamta; Mehra, R.M.

2010-01-01

ZnO films codoped with 5 at.% Co and 1 at.% Al were prepared by sol-gel technique on corning glass and silicon substrates with precursor sols of different pH values. The pH was varied from 5.4 to 11 by adding varying amounts of monoethanolamine to the sol. Since pH plays an important role in controlling the properties of films, we discuss in detail the effect of pH value on the structural, morphological and optical properties of the grown films. X-ray diffraction and atomic force microscopy images reveal that the size of crystallites increases with pH of the sol. The variation of pH in the reaction system influences the density of homogeneous nucleation and the crystal growth along the c-axis. High quality Co and Al codoped ZnO films annealed at 600 o C have been obtained using a sol with pH = 9. These sol-gel derived films find their suitability to be used as dilute magnetic semiconductors.

Sol-gel derived zinc oxide films alloyed with cobalt and aluminium

Energy Technology Data Exchange (ETDEWEB)

Sharma, Mamta [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021 (India); Mehra, R.M., E-mail: rammehra2003@yahoo.co [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021 (India)

2010-05-03

ZnO films codoped with 5 at.% Co and 1 at.% Al were prepared by sol-gel technique on corning glass and silicon substrates with precursor sols of different pH values. The pH was varied from 5.4 to 11 by adding varying amounts of monoethanolamine to the sol. Since pH plays an important role in controlling the properties of films, we discuss in detail the effect of pH value on the structural, morphological and optical properties of the grown films. X-ray diffraction and atomic force microscopy images reveal that the size of crystallites increases with pH of the sol. The variation of pH in the reaction system influences the density of homogeneous nucleation and the crystal growth along the c-axis. High quality Co and Al codoped ZnO films annealed at 600 {sup o}C have been obtained using a sol with pH = 9. These sol-gel derived films find their suitability to be used as dilute magnetic semiconductors.

Characterization of nanocrystalline ZnO:Al films by sol-gel spin coating method

Energy Technology Data Exchange (ETDEWEB)

Gareso, P. L., E-mail: pgareso@gmail.com; Rauf, N., E-mail: pgareso@gmail.com; Juarlin, E., E-mail: pgareso@gmail.com [Department of Physics, Faculty of Mathematics and Natural Sciences, Hasanuddin University, Makassar 90245 (Indonesia); Sugianto,; Maddu, A. [Department of Physics, Faculty of Mathematics and Natural Sciences, Bogor Institute of Culture, IPB Bogor (Indonesia)

2014-09-25

Nanocrystalline ZnO films doped with aluminium by sol-gel spin coating method have been investigated using optical transmittance UV-Vis and X-ray diffraction (X-RD) measurements. ZnO films were prepared using zinc acetate dehydrate (Zn(CH{sub 3}COO){sub 2}@@‡2H{sub 2}O), ethanol, and diethanolamine (DEA) as a starting material, solvent, and stabilizer, respectively. For doped films, AlCl{sub 3} was added to the mixture. The ZnO:Al films were deposited on a transparent conductive oxide (TCO) substrate using spin coating technique at room temperature with a rate of 3000 rpm in 30 sec. The deposited films were annealed at various temperatures from 400°C to 600°C during 60 minutes. The transmittance UV-Vis measurement results showed that after annealing at 400°C, the energy band gap profile of nanocrystalline ZnO:Al film was a blue shift. This indicated that the band gap of ZnO:Al increased after annealing due to the increase of crystalline size. As the annealing temperature increased the bandgap energy was a constant. In addition to this, there was a small oscillation occurring after annealing compared to the as–grown samples. In the case of X-RD measurements, the crystalinity of the films were amorphous before annealing, and after annealing the crystalinity became enhance. Also, X-RD results showed that structure of nanocrystalline ZnO:Al films were hexagonal polycrystalline with lattice parameters are a = 3.290 Å and c = 5.2531 Å.

Preparation of CuAlO2 Thin Films by Sol-Gel Method Using Nitrate Solution Dip-Coating

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Ehara Takashi

2016-01-01

Full Text Available CuAlO2 thin films are prepared by sol-gel dip-coating followed by annealing in nitrogen atmosphere using copper nitrate and aluminum nitrate as metal source materials. X-ray diffraction (XRD patterns show (003, (006 and (009 oriented peaks of CuAlO2 at annealing temperature of 800 – 1000°C. This result indicates that the CuAlO2 films prepared in the present work are c-axis oriented. XRD peak intensity increase with annealing temperature and becomes maximum at 850°C. The CuAlO2 XRD peak decreased at annealing temperature of 900°C with appearance of a peak of CuO, and then increased again with annealing temperature until 1000 °C. The films have bandgap of 3.4 eV at annealing temperature of 850°C in which the transparency becomes the highest. At the annealing temperature of 850°C, scanning electron microscope (SEM observation reveals that the films are consist of amorphous fraction and microcrystalline CuAlO2 fraction.

Fabrication and application of mesoporous TiO{sub 2} film coated on Al wire by sol-gel method with EISA

Energy Technology Data Exchange (ETDEWEB)

Zhao, Linkang; Lu, Jianjun, E-mail: lujianjunktz@tyut.edu.cn

2017-04-30

Highlights: • Successfully fabricated mesoporous TiO{sub 2} thin film on Al wire by sol-gel method with EISA. • Ni supported on this film and exhibits good methanation performance. • Investigate the decomposition temperature of template agent F127 in TiO{sub 2} precursor system. - Abstract: Mesoporous TiO{sub 2} film on Al wire was fabricated by sol-gel method with evaporation induced self assembly (EISA) process using F127 as templating agent in the mixed solution of ethanol and Tetra-n-butyl Titanate. The Ni/TiO{sub 2} film catalyst supported on Al wire was prepared by impregnation and the catalytic performance on methanation was carried out in a titanium alloy micro-reactor tube. It was shown that anatase mesoporous TiO{sub 2} film was prepared in this conditions (1 g F127,calcined at 400 °C and aged for 24 h), which has specific surface area of 127 m{sup 2} g{sup −1} and narrow pore size distribution of 5.3 nm. Low calcined temperature (300 °C) cannot transfer film to anatase and decompose F127 completely. Ni/TiO{sub 2} film on Al wire catalyst was proved to be active in CO methanation reaction. And the CO conversion reaches 99% and CH{sub 4} selectivity close is to 80% when the reaction temperature is higher 360 °C.

Synthesis by Sol-gel and characterization of catalysts Ag/Al{sub 2}O{sub 3}-CeO{sub 2}; Sintesis por Sol-gel y caracterizacion de catalizadores Ag/Al{sub 2}O{sub 3}-CeO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Zayas, M.L.; Perez H, R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Rubio, E. [BUAP, Centro de Vinculacion, 72000 Puebla (Mexico); Velasco, A. [BUAP, Facultad de Quimica, 72000 Puebla (Mexico)

2004-07-01

Aluminia, cerium and mixed oxides Al{sub 2}O{sub 3}-CeO{sub 2} with different relationship Al/Ce (0.75, 0.50 and 0.25) were prepared by sol-gel and used as support for the Ag. The samples were characterized by XRD, DRIFT, TPR and adsorption of N{sub 2} to temperature of liquid nitrogen. The surface area BET showed that the materials that contain aluminia present near values among them. XRD allowed to identify to the cerianite in the oxides that whose support contains cerium and to the {alpha}-aluminia. A mixture of phases was observed in the aluminia. Vibration bands attributed to the bond Al-O and Ce-O were observed by DRIFT in the catalytic materials. TPR showed differences in the reducibility of the Ag precursor in the indicative catalysts of a different interaction with the support. (Author)

Algunas Observaciones sobre el Desecamiento del Grano de Cacao Bajo Diferentes Condiciones

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Platone E.

1949-12-01

Full Text Available Las diversas modalidades del proceso de desecamiento del cacao fermentado (con tal de que la temperatura de desecamiento no sea muy elevada tienen escasa influencia sobre la calidad aparente del grano, a condición desde luego, de que el proceso sea llevado hasta lograr un mismo porcentaje de humedad en los granos. Ya se sabía que, aparentemente, debería preferirse el desecamiento artificial, al natural, por cuanto se logra un mejor control de la temperatura y de otras condiciones del proceso. En realidad, los fabricantes prefieren, en igualdad de condiciones, el cacao desecado al sol. A este propósito había sido establecido por la Oficina Internacional de Fabricantes de Cacao y Chocolate, según dice Knapp (ya citado, que el cacao que hubiese sido secado a más de 50°C, fuera específicamente rotulado como "desecado artificialmente". Sin embargo, el desecamiento al sol significa ordinariamente para los granos, una temperatura notoriamente superior a dichos 50oC, aunque por lo regular no suprior a 60°C.

ESTUDIO DE LAS PROPIEDADES FÍSICAS Y DE LA CINÉTICA DE SECADO DE GRANOS DE MAIZ COLORADO DURO

Directory of Open Access Journals (Sweden)

Matías R. Ordóñez

2012-01-01

Full Text Available Se estudió el efecto de la humedad sobre propiedades físicas de granos de maíz Colorado Duro en el rango 17− 35% base seca, y la cinética de secado a temperaturas entre 30− 90°C y a velocidad de 0.43 m/s. El 12.91x10-3 m, diámetro contenido de humedad tuvo efecto significativo sobre la longitud (12.059x10-3− -3 -3 -3 -3 geométrico (7.8x10 − 8.281x10 m, diámetro equivalente (8.18x10 − 8.63x10 m, peso de mil granos (363.6− 421.9 g, ángulo de reposo (10.11− 24.66°, y densidades aparente (0.801− 0.684 g/mL y real (1.339− 1.170 g/mL; pero el ancho, espesor, porosidad y esfericidad no se vieron significativamente afectados. El secado ocurrió en el período de velocidad decreciente, siendo el tiempo de secado y la temperatura las variables significativas sobre la humedad del grano. Los modelos de Page, ecuación difusiva de “tiempos cortos” y una modificación introducida a éste ultimo resultaron adecuados (R2>0.99 para describir los datos. Los coeficientes de difusión de agua estuvieron entre 1.907x10-11 y 6.495x10-11 m2/s, y la energía de activación fue 17.74 kJ/mol.

Characterisation of a new alkoxide sol-gel hydroxyapatite

International Nuclear Information System (INIS)

Green, D.D.; Kannangara, G.S.K.; Milev, A.; Ben-Nissan, B.

1999-01-01

Hydroxyapatite (HAp) coatings have been used to promote bone growth and fixation towards implant surfaces to encourage faster recovery times for the recipient. Current coating processing techniques, capable of producing thin HAp layers are pulsed-laser deposition and sputtering (high-temperature processing). Other technologies are in vitro methods, electrodeposition and sol-gel, due to the fact that these techniques utilise lower processing temperatures they avoid structural instabilities of HAp at elevated temperatures. The term sol-gel encompasses any process of producing ceramic materials (single and mixed oxides, as well as non-oxides e.g. nitrides) from solutions. The sol-gel process was first identified by Ebelman, and has been used to produce ceramic powders, coatings, and bulk materials including glasses. The implementation of a sol-gel methodology enables increased stoichiometry and homogeneity, while having the ability to coat complex shapes. Sol-gel hydroxyapatite reported by Chai et al. employed tri ethyl phosphite [ P(OEt) 3 ] as the staring phosphorus alkoxide precursor, whereby it was established that in order to obtain monophasic hydroxyapatite upon firing there must be a 24 hour ripening period. The ripening period was determined to be an equilibrium step whereby the equilibrium intermediate phase lied in favour of a diethyl phosphite arrangement (species) within the sol. Therefore, the work here under taken was to produce hydroxyapatite using diethyl phosphite [HOP(OEt) 2 ] as a starting alkoxide precursor with a final aim to reduce or eliminate the ageing period as observed by Chai et al in P(OEt) 3 solutions

Sistema de secado combinado para cerámica mediante tecnología microondas para el sector de la cerámica hasta formato 1200

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TECNOLOGIA,SL, BULMA

2010-04-01

Full Text Available New team of passage by technology microwaves for dried laminar of materials of high absorption, and dried green porcelain format until 1200 mm and thicknesses until 25 mm. It allows the elimination of water with improvement of productivity, energetic efficiency and clean technology for processed of marble, natural stone, ceramic tiles, plasters and products in bulk, without broadcasts of CO₂, and respectful with the Nature, allows the dried with low degree. Project manufactured and designed totally by BULMA situated in L’Alcudia protected with national patent number P200931081.

Nuevo equipo de pasaje por tecnología microondas para secado laminar de materiales de alta absorción,y secado de bizcocho en verde formato hasta 1200 mm y espesores hasta 25 mm. Permite la eliminación de humedad con mejora de productividad, eficiencia energética y tecnológicamente limpios para procesado de mármol, piedra natural, cerámica, escayola y productos a granel, sin emisiones de CO₂, y respetuoso con el medio ambiente, permite el secado con bajos gradientes, fabricado y diseñado íntegramente por empresa valenciana BULMA situada en L’Alcudia protegido con patente nacional P200931081 y en tramite internacional.

Tomato Infrared Drying: Modeling and some Coefficients of the Dehydration Process Secado de Tomate por Infrarrojo: Modelación y algunos Coeficientes del Proceso de Deshidratación

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Paulo Cesar Corrêa

2012-06-01

, el presente trabajo tuvo como objetivo el estudio del proceso de deshidratación en tres diferentes estados de maduración de rebanadas de tomate (Solanum lycopersicum L. por medio del secado por infrarrojo, usando dos métodos: aproximación del período constante de deshidratación a la teoría de la transferencia de calor y masa para el termómetro de bulbo húmedo; y al período decreciente de la deshidratación a la teoría de difusión de líquidos. Se utilizaron frutos de tomate cv. Santa Cruz. Tres estados de maduración fueron obtenidos: verde (estado 1, naranja (estado 2 y rojo (estado 3. Modelos matemáticos usualmente utilizados para representar el secado de productos agrícolas fueron ajustados a los datos experimentales del secado de tomate. El coeficiente de difusión efectivo fue obtenido por medio del ajuste del modelo matemático de difusión líquida a los datos experimentales del período decreciente de deshidratación. El modelo Dos Términos representó mejor el proceso del secado de rebanadas de tomate. La humedad crítica para la deshidratación de tomate fue 2.97 kgw kgdm-1. Existe un período inicial de deshidratación en que la tasa de secado alcanzó el máximo (aproximadamente 1.05 kgw kgdm-1, alrededor de 3 min. Tres diferentes métodos fueron utilizados para obtener los valores del coeficiente efectivo de difusión, incluyendo el método de elementos finitos, en que presentó los menores valores de la suma de desviaciones mínimas al cuadrado, 1.00 x 10-7 m² s-1. El coeficiente global de transferencia de calor fue 12.45 W m-2 K-1, y el coeficiente global de transferencia de masa fue 0.0105 m s-1.

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

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

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Naísma Hernández-Jatib

2009-03-01

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

Radiation hardening in sol-gel derived Er3+-doped silica glasses

International Nuclear Information System (INIS)

Hari Babu, B.; León Pichel, Mónica; Ollier, Nadège; El Hamzaoui, Hicham; Bigot, Laurent; Savelii, Inna; Bouazaoui, Mohamed; Poumellec, Bertrand; Lancry, Matthieu; Ibarra, Angel

2015-01-01

The aim of the present paper is to report the effect of radiation on the Er 3+ -doped sol-gel silica glasses. A possible application of these sol-gel glasses could be their use in harsh radiation environments. The sol-gel glasses are fabricated by densification of erbium salt-soaked nanoporous silica xerogels through polymeric sol-gel technique. The radiation-induced attenuation of Er 3+ -doped sol-gel silica is found to increase with erbium content. Electron paramagnetic resonance studies reveal the presence of E′ δ point defects. This happens in the sol-gel aluminum-silica glass after an exposure to γ-rays (kGy) and in sol-gel silica glass after an exposure to electrons (MGy). The concentration levels of these point defects are much lower in γ-ray irradiated sol-gel silica glasses. When the samples are co-doped with Al, the exposure to γ-ray radiation causes a possible reduction of the erbium valence from Er 3+ to Er 2+ ions. This process occurs in association with the formation of aluminum oxygen hole centers and different intrinsic point defects

Innovative Formulation Combining Al, Zr and Si Precursors to Obtain Anticorrosion Hybrid Sol-Gel Coating

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Clément Genet

2018-05-01

Full Text Available The aim of our study is to improve the aluminium alloy corrosion resistance with Organic-Inorganic Hybrid (OIH sol-gel coating. Coatings are obtained from unusual formulation with precursors mixing: glycidoxypropyltrimethoxysilane (GPTMS, zirconium (IV propoxide (TPOZ and aluminium tri-sec-butoxide (ASB. This formulation was characterized and compared with sol formulations GPTMS/TPOZ and GPTMS/ASB. In each formulation, a corrosion inhibitor, cerium (III nitrate hexahydrate, is employed to improve the corrosion performance. Coatings obtained from sol based on GPTMS/TPOZ/ASB have good anti-corrosion performances with Natural Salt Spray (NSS resistance of 500 h for a thickness lower than 4 µm. Contact angle measurement showed a coating hydrophobic behaviour. To understand these performances, nuclear magnetic resonance (NMR analyses were performed, results make sol-gel coating condensation evident and are in very good agreement with previous results.

Innovative Formulation Combining Al, Zr and Si Precursors to Obtain Anticorrosion Hybrid Sol-Gel Coating.

Science.gov (United States)

Genet, Clément; Menu, Marie-Joëlle; Gavard, Olivier; Ansart, Florence; Gressier, Marie; Montpellaz, Robin

2018-05-10

The aim of our study is to improve the aluminium alloy corrosion resistance with Organic-Inorganic Hybrid (OIH) sol-gel coating. Coatings are obtained from unusual formulation with precursors mixing: glycidoxypropyltrimethoxysilane (GPTMS), zirconium (IV) propoxide (TPOZ) and aluminium tri-sec-butoxide (ASB). This formulation was characterized and compared with sol formulations GPTMS/TPOZ and GPTMS/ASB. In each formulation, a corrosion inhibitor, cerium (III) nitrate hexahydrate, is employed to improve the corrosion performance. Coatings obtained from sol based on GPTMS/TPOZ/ASB have good anti-corrosion performances with Natural Salt Spray (NSS) resistance of 500 h for a thickness lower than 4 µm. Contact angle measurement showed a coating hydrophobic behaviour. To understand these performances, nuclear magnetic resonance (NMR) analyses were performed, results make sol-gel coating condensation evident and are in very good agreement with previous results.

Reversible sol-gel-sol medium for enzymatic optical biosensors

NARCIS (Netherlands)

Safaryan, S.; Yakovlev, A.; Pidko, E.A.; Vinogradov, A.; Vinogradov, V.

2017-01-01

In this paper we for the first time report a reversible sol-gel-sol approach to obtain optical enzymatic biosensors with improved enzyme stability and good sensitivity by using desktop inkjet printing. The developed technique is based on the bio-inorganic inks allowing for a sol-gel-sol transition

Cinética del secado de tomillo Drying kinetics of thyme

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Ronicely P. da Rocha

2012-06-01

Full Text Available Los objetivos del trabajo fueran estudiar la cinética del secado de tomillo con posterior ajuste de diferentes modelos matemáticos a los datos experimentales y determinar los valores de la difusividad efectiva y energía de activación. Para el desarrollo del experimento de secado fueran utilizadas las temperaturas 30, 40, 50, 60 y 70 oC. El diseño experimental fue de bloques completamente aleatorizados, con tres repeticiones. Para el ajuste de los modelos matemáticos a los datos experimentales fue realizado el análisis de regresión no lineal, por el método Simplex-Quasi-Newton. Los resultados mostraron que el modelo matemático de Page obtuve un mejor ajuste a los datos experimentales, los valores de los coeficientes de difusividad efectiva variaron entre 3,69 x 10-12 e 1,19 x 10-10 m² s-1 y el valor de la energía de activación fue de 77,16 kJ mol-1.This work aimed to study the drying kinetics of thyme and subsequent adjustment of different mathematical models to the experimental data and to determine the effective diffusivity and the activation energy. In order to conduct the experiment the temperatures of 30, 40, 50, 60, 70 ºC were used. The experimental design employed was in randomized blocks with three repetitions. For the adjustment of the mathematical models to the experimental data non-linear regression was performed using Simplex-Quasi-Newton method. The results showed that the Page model was the one that promoted the best fit of the experimental data to describe the drying kinetics of the thyme leaves. The values of effective diffusivity coefficients ranged between 3.69 x 10-12 and 1.19 x 10-10 m² s-1 and the value of activation was 77.16 kJ mol-1.

Effect of TiO2/Al2O3 film coated diamond abrasive particles by sol-gel technique

Science.gov (United States)

Hu, Weida; Wan, Long; Liu, Xiaopan; Li, Qiang; Wang, Zhiqi

2011-04-01

The diamond abrasive particles were coated with the TiO2/Al2O3 film by the sol-gel technique. Compared with the uncoated diamonds, the TiO2/Al2O3 film was excellent material for the protection of the diamonds. The results showed that the incipient oxidation temperature of the TiO2/Al2O3 film coated diamonds in air atmosphere was 775 °C, which was higher 175 °C than that of the uncoated diamonds. And the coated diamonds also had better the diamond's single particle compressive strength and the impact toughness than that of uncoated diamonds after sintering at 750 °C. For the vitrified bond grinding wheels, replacing the uncoated diamonds with the TiO2/Al2O3 film coated diamonds, the volume expansion of the grinding wheels decreased from 6.2% to 3.4%, the porosity decreased from 35.7% to 25.7%, the hardness increased from 61.2HRC to 66.5HRC and the grinding ratio of the vitrified bond grinding wheels to carbide alloy (YG8) increased from 11.5 to 19.1.

Alumina support prodn. with active component by sol-gel method - and use esp. for regenerative absorption of sulphur dioxide, oxygen or hydrogen sulphide

NARCIS (Netherlands)

Frens, G.

1991-01-01

Prodn. of a support contg. Al2O3 with an active component and/or precursor for this is carried out by the sol/gel technique by (a) producing a sol from AlCl3 or material forming Al2O3, (b) supplying the sol to the top of a column filled with a water-immiscible solvent (I) in the upper pt. and an

SOL: INNOVACIÓN ON-LINE

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Rubén Faúndez

2007-11-01

Full Text Available Las aplicaciones de simulación tienden a ser cada vez más cercanas a usuarios e industrias. Sin embargo, muchas de ellas no poseen ni la capacidad ni el conocimiento como para desarrollar internamente sus modelos de simulación. Por este motivo, y como una forma de apoyar la toma de decisiones basándose en modelos de simulación, se presenta la plataforma SOL (Simulación On Line. La metodología completa de trabajo, así como la interacción entre SOL, Empresa y Asesor, son presentadas. Su base de datos, los niveles de usuarios, sus funcionalidades, y la creación automatizada de información grafica y visual, también son explicadas. En el caso de aplicación, el uso de SOL para apoyar la toma de decisiones en una operación de movimiento de material, permite a los tomadores de decisión acceder a análisis robustos basados en información extraída de los modelos de simulación. SOL, al almacenar información, funcionar vía web, generar análisis automatizados y crear visualizaciones, permite cumplir con las expectativas de los usuarios respecto a una solución integral en simulación.

Predicting the drying shrinkage behavior of high strength portland cement mortar under the combined influence of fine aggregate and steel micro fiber; Predicción del comportamiento de retracción por secado de morteros de cemento Pórtland de alta resistencia bajo la influencia combinada de árido fino y micro fibra de acero.

Energy Technology Data Exchange (ETDEWEB)

Li, Zhengqi

2017-07-01

The workability, 28-day compressive strength and free drying shrinkage of a very high strength (121-142 MPa) steel micro fiber reinforced portland cement mortar were studied under a combined influence of fine aggregate content and fiber content. The test results showed that an increase in the fine aggregate content resulted in decreases in the workability, 28-day compressive strength and drying shrinkage of mortar at a fixed fiber content. An increase in the fiber content resulted in decreases in the workability and drying shrinkage of mortar, but an increase in the 28-day compressive strength of mortar at a fixed fine aggregate content. The modified Gardner model most accurately predicted the drying shrinkage development of the high strength mortars, followed by the Ross model and the ACI 209R-92 model. The Gardner model gave the least accurate prediction for it was developed based on a database of normal strength concrete. [Spanish] Se ha estudiado la trabajabilidad, resistencia a la compresión (28 días) y la retracción al secado de morteros de cemento Pórtland de muy alta resistencia (121-142 MPa) reforzados con micro fibra de acero, con la influencia combinada de contenido de árido fino y de micro fibra de acero. El aumento en el contenido de árido fino resultó en la disminución de la trabajabilidad, resistencia a la compresión y la retracción por secado de los morteros con un contenido de fibra específico. El aumento en el contenido de fibra dio lugar a la disminución de la trabajabilidad y la retracción por secado, y a un aumento en la resistencia a la compresión a 28 días en morteros con un contenido específico de á rido fino. El modelo modificado de Gardner predijo con más precisión la retracción por secado de mortero de alta resistencia, seguido por el modelo de Ross y el modelo ACI 209R-92. El modelo de Gardner dio la predicción menos exacta debido al hecho de que se desarrolló sobre bases de datos de hormigones de resistencia normal.

SECADO DE UCHUVA (Physalis peruviana L) POR AIRE CALIENTE CON PRETRATAMIENTO DE OSMODESHIDRATACIÓN

OpenAIRE

CASTRO, Adriana M; RODRÍGUEZ, Ligia; VARGAS, Edgar M

2008-01-01

En este trabajo se determinan las condiciones de temperatura más favorables para un proceso de secado de uchuva (Physalis peruviana L) con aire caliente, con deshidratación osmótica (DO) como pretratamiento, utilizando una solución de sacarosa de 70o Brix a 40oC durante 16 horas. Se realiza un seguimiento de la degradación de β-caroteno con el tiempo y la temperatura. En la fruta tratada con aire caliente a 60oC y pretratada con DO, se obtiene una pérdida total de β-caroteno del 98%. La fruta...

Effect of hydrothermal process for inorganic alumina sol on crystal structure of alumina gel

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K. Yamamura

2016-09-01

Full Text Available This paper reports the effect of a hydrothermal process for alumina sol on the crystal structure of alumina gel derived from hydrothermally treated alumina sol to help push forward the development of low temperature synthesis of α-Al2O3. White precipitate of aluminum hydroxide was prepared with a homogeneous precipitation method using aluminum nitrate and urea in aqueous solution. The obtained aluminum hydroxide precipitate was peptized by using acetic acid at room temperature, which resulted in the production of a transparent alumina sol. The alumina sol was treated with a hydrothermal process and transformed into an alumina gel film by drying at room temperature. Crystallization of the alumina gel to α-Al2O3 with 900 °C annealing was dominant for a hydrothermal temperature of 100 °C and a hydrothermal time of 60 min, as production of diaspore-like species was promoted with the hydrothermal temperature and time. Excess treatments with hydrothermal processes at higher hydrothermal temperature for longer hydrothermal time prevented the alumina gel from being crystallized to α-Al2O3 because the excess hydrothermal treatments promoted production of boehmite.

Superhydrophobic properties induced by sol-gel routes on copper surfaces

Science.gov (United States)

Raimondo, M.; Veronesi, F.; Boveri, G.; Guarini, G.; Motta, A.; Zanoni, R.

2017-11-01

Superhydrophobic surfaces are attracting increasing attention in different fields such as energy, transportation, building industry and electronics, as they exhibit many interesting properties such as high water repellence, anti-fogging, anti-corrosion, anti-fouling and self-cleaning abilities. Here, superhydrophobic nanostructured hybrid materials obtained by depositing alumina nanoparticles on copper surfaces via dip coating in Al2O3 sol are presented. Two different preparation routes were explored, based on either an alcoholic or an aqueous Al2O3 sol, and the resulting wetting properties were compared. Wettability measurements showed that when the alcoholic sol is used superhydrophobicity is attained, with values of water contact angle very close to the upper limit of 180°, while highly hydrophobic coatings are obtained with the aqueous sol. These findings were further supported by electron microscopy and X-ray photoelectron spectroscopy, which revealed that the surface layer deposited on Cu is more homogenous and richer in alumina nanoparticles when the alcoholic sol was used. Durability of the superhydrophobic coating was assessed by performing ageing tests in chemically aggressive environments. A remarkable resistance is displayed by the superhydrophobic coating in acid environment, while alkaline conditions severely affect its properties. Such behaviors were investigated by XPS and FE-SEM measurements, which disclosed the nature of the surface reactions under the different conditions tested. The present results underline that a thorough investigation of surface morphology, chemical composition and wetting properties reveals their strongly connection and helps optimizing the combination of substrate nanostructuring and suitable chemical coating for an improved durability in different aggressive environments.

sol y playa: el caso de Tenerife

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Ricardo J. Díaz Armas

2008-01-01

Full Text Available El turismo del vino tiene una concepción distinta en un destino masivo de sol y playa. En este caso el enoturismo convive con ese modelo turístico y es un producto complementario que favorece la diversificación en la oferta actual. El turismo del vino puede complementar la ya existente oferta turística, con lo que las regiones, turísticas y a la vez viníferas, podrían apoyarse en las experiencias y conocimiento del vino por parte del visitante y utilizarlas como hecho diferencial competitivo frente a otros destinos de sol y playa que no poseen esta particularidad. Con ello además se favorecerá el lanzamiento del producto turístico del vino, pues la demanda latente ya esta en las zonas turísticas que rodean el área vinícola. En este sentido, una vez que se descubren las motivaciones para acudir al destino Tenerife, se localiza un mercado sensible a la ruta del vino Tacoronte-Acentejo en el asentamiento turístico del Puerto de la Cruz (una de las principales zonas turísticas de Tenerife. Así, tras conocer los beneficios buscados por el visitante del Puerto de la Cruz, se ha contrastado la existencia de dos segmentos latentes que pueden ser atraídos hacia la oferta actual de la ruta del vino en Tacoronte-Acentejo, al verificar que persiguen, además del clima y el sol y playa (principales motivaciones para viajar al destino Tenerife, otros beneficios que son susceptibles de ser ofertados por la ruta del vino.

Texto e imagen en España de sol a sol de Alfonso Armada

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Champeau, Geneviève

2011-06-01

Full Text Available España de sol a sol (2001 by Alfonso Armada gives an example of the development of the «travel narrative» genre in Spain today. Faced with the «end of travel» (Marc Augé, he proposes a renovation of the perception of the familiar by travelling across Spain and Portugal and by substituting «endotic» (Georges Pérec for exotic.The poetics in the narrative differs greatly from that by travelling writers of «social realism», in the Spain of the sixties. Interpretation replaces information, the poetic image prevails over the referential function of language, and polysemy, omnipresent intertexuality and metatextuality play an important part. The change also affects the links between text and image, which are now more complementary than redundant. Playing with stereotypes, the photography actively contributes to establishing argumentative strategies meant to make the reader-viewer adhere to the message, all while affirming itself as an autonomous aesthetic experience.España de sol a sol (2001 de Alfonso Armada proporciona una muestra de la evolución del género del «libro de viajes» en la España contemporánea. Ante la imposibilidad del viaje (Marc Augé, propone renovar la percepción de lo familiar recorriendo el espacio nacional y sustituyendo el «endotismo» (Georges Pérec al exotismo. La poética del viaje que propone el relato difiere profundamente de la de los escritores viajeros del «realismo social», en la España de los años sesenta, anteponiendo la interpretación a la información, la imagen poética a la función referencial del lenguaje, cultivando la polisemia, una intertextualidad masiva y una reflexión metatextual. Distintos son también los vínculos que se establecen entre texto e imagen, de complementariedad más que de redundancia. La fotografía participa activamente, por la reelaboración de tópicos, del dispositivo argumentativo destinado a favorecer la adhesión del lector-espectador al mensaje y se afirma

Parámetros de Transferencia de Materia en el Secado de Frutas, sin Necesidad de Datos de Disminución de Volumen Mass Transfer Parameters in Fruit Drying, without using Shrinkage Data

OpenAIRE

Sebastião R Ferreira; Antônio R. S Costa

2010-01-01

Se desarrolló una metodología analítica para evaluar parámetros de transferencia de materia en el secado de frutas cilindricas, sin necesidad de conocer datos de disminución de volumen, pero admitiendo implícitamente disminución de su radio en el proceso R. Con el procedimiento se predice el coeficiente externo de transferencia de materia k m, la difusividad efectiva del agua en frutos De f, el número de Biot Bi y el radio promedio Rm durante el secado. Para probar la metodología es necesario...

Mullite evolution in ceramics derived from clay, and sol-gel precursors

International Nuclear Information System (INIS)

Rezaie, H.R.; Naghizadeh, R.; Golestani-Fard, F.

2002-01-01

Mullite formation from sol-gel (behemoth and colloidal silica), and clay has been compared and the microstructural evolution examined using electron-optical techniques and XRD. The relationship between processing route and reaction sequence to form mullite is discussed. In sol-gel processing γAloof transforms to γ-Al 2 O 3 at 400-500 d eg w ithout an isothermal hold. δ-Al 2 O 3 was present after cooling directly from 1100 d eg i n air.(δ+θ)Al 2 O 3 were present above 1200 d eg . Reaction between (δ+θ)Al 2 O 3 and amorphous silica produced 3:2 mullite at∼ 1370 d eg . In kaolin, meta kaolin transforms to spinel and mullite at 980-1000 d eg w ithout an isothermal hold. Melanostatin to 3:2 mullite took place at 1200-1250 d eg . Cristobalite was observed after quenching from 1200 d eg , but could not be detected after cooling directly from 1590 d eg

Influence of annealing temperature on optical properties of Al doped ZnO nanoparticles via sol-gel methods

Science.gov (United States)

Rashid, Affa Rozana Abd; Hazwani, Tuan Nur; Mukhtar, Wan Maisarah; Taib, Nur Athirah Mohd

2018-06-01

Zinc oxide (ZnO) thin films have become technologically important materials due to their wide range of electrical and optical properties. The characteristics can be further adjusted by adequate doping processes. The effect of dopant concentration of Al, heating treatment and annealing in reducing atmosphere on the optical properties of the thin films is discussed. Undoped and aluminum-doped zinc oxide (AZO) thin films are prepared by the sol-gel method. Zinc acetate dihydrate, 2-methoxyethanol and monoethanolamine are used as precursor, solvent and stabilizer. In the case of AZO, aluminum nitrate nanohydrate is added to the precursor solution with an atomic percentage equal to 0 %, 1 %, 2 % and 3 % of Al. The multi thin layers are transformed into ZnO upon annealing at 450 °C and 500 °C. The optical properties such as transmittance, absorbance, band gap and refractive index of the thin films have been investigated by using UV-Visible Spectroscopy (UV-Vis). The results show that the effect of aluminium dopant concentration on the optical properties is depend on the post-heat treatment of the films. By doping with Al, the transmittance spectra in visible range increased and widen the band gap of ZnO which might due to Burstein-moss effects.

SIMULACIÓN MATEMÁTICA DEL PROCESO DE SECADO DE LA GRACILARIA CHILENA (GRACILARIA CHILENSIS MATHEMATICAL SIMULATION OF DRYING PROCESS OF CHILEAN GRACILARIA (GRACILARIA CHILENSIS

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Antonio Vega Gálvez

2007-04-01

Full Text Available El objetivo de este trabajo es estudiar y modelar la cinética de secado por aire caliente del alga Gracilaria (Gracilaria chilensis utilizando un secador convectivo diseñado y construido en la Facultad de Ingeniería de la Universidad de La Serena a cinco temperaturas de bulbo seco (30, 40, 50, 60 y 70ºC y velocidad de aire de 2.0±0.2 m.s-1. Para el modelado matemático se utilizan tres modelos empíricos (Newton, Henderson-Pabis & Page. Durante el experimento se observa solamente el periodo de velocidad decreciente, por lo que se utiliza la ecuación de la segunda Ley de Fick para el cálculo de la difusividad efectiva de agua. El proceso de secado presenta humedades finales entre 0.096 g agua/g m.s y 0.061 g agua/g m.s para 30ºC y 70ºC, respectivamente. Tanto la difusividad como los parámetros cinéticos k1, k2 y k3 de los modelos propuestos presentan dependencia con la temperatura y al evaluarlos con la ecuación de Arrhenius se obtienen energías de activación de 39.92, 33.85, 33.49 y 33.83 kJ·mol-1, respectivamente. De acuerdo a los análisis estadísticos que se utilizan (r2, SSE, RMSE y X², el modelo de Page muestra la mejor calidad de ajuste sobre los datos experimentales, otorgando así una buena herramienta para el modelado de la cinética de secado industrial de la Gracilaria chilensis y el cálculo del tiempo de secado a diferentes temperaturas, con el fin de alcanzar un contenido de humedad comercial aceptable internacionalmente.The aim of this research is to study and to model the hot air drying kinetics of Gracialaria algae (Gracilaria chilensis, using a convective drier -designed and built at the Faculty of Engineering of Universidad de La Serena- at five dry bulb temperatures (30, 40, 50, 60 and 70ºC and an air velocity of 2.0 ± 0.2 m.s-1. Three empirical models are used for the mathematic modeling (Newton, Henderson-Pabis & Page. During the experiment, only a falling rate period is observed, hence the Fick's second

Obtención de Cordierita por Sol-Gel a partir de fuentes nacionales cubanas

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Pacheco, P.

2003-10-01

Full Text Available For cordierite synthesis through the Sol-Gel method, the sodium silicate obtained from the dissolution of a solid residue coming from the aluminum sulfate production based on kaolin, was used. The sources of magnesium and aluminum were obtained using the technologies previously developed by CIPIMM. The elements were mixed in a determined order and quantity to obtain a Gel with cordierite stechiometry. The gel was washed and dried and briquettes were made to treat them at different temperatures, obtaining cordierite in a major phase at 1200ºC. This was checked through the X-Ray diffraction analysis of the products coming from the thermical treatment. The method used when compared to the traditional ones, permitted to reduce crystallization temperature, obtaining more dense products and clean technology.

Para la síntesis de la Cordierita por el método de Sol-Gel se utilizó, el silicato de sodio, obtenido de la disolución de un residuo sólido proveniente de la producción de sulfato de aluminio a partir de caolín. Los precursores de magnesio y aluminio fueron obtenidos utilizando las tecnologías previamente desarrolladas por el CIPIMM. Los materiales fueron mezclados en un orden y cantidad determinada hasta obtener el Gel con estequiometría de cordierita. El gel fue lavado, secado, briqueteado y tratado térmicamente a diferentes temperaturas, lográndose cordierita en fase mayoritaria a los 1200 ºC, lo cual fue corroborado mediante el análisis por difracción de rayos X de los productos del tratamiento térmico. El método utilizado comparado con los tradicionales permitió reducir la temperatura de cristalización, obtener productos más densificados y tecnología limpia.

Puesto remisión de V. sol puesto a sol puesto, de.

OpenAIRE

2011-01-01

[ES] Definición del término Puesto remisión de V. sol puesto a sol puesto, de. en el diccionario Dicter. [EN] Definition of the word Puesto remisión de V. sol puesto a sol puesto, de. in the dictionary Dicter.

INKJET PRINTING OF ALUMOOXIDE SOL FOR DEPOSITION OF ANTIREFLECTING COATINGS

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E. A. Eremeeva

2017-01-01

Full Text Available Subject of Research. This work describes for the first time the formation of antireflective coating on the base of boehmite phase of AlOOH with low refractive index (1.35 by inkjet printing on the nonporous substrate. This method gives the possibility to increase the contrast of colorful interfering images by 32% obtaining by inkjet printing of titanium dioxide sol. The usage of this technology enables to obtain patterns with wide viewing angle and makes them highly stable. Methods. Traditional sol-gel method with peptizing agents and heating for 90oC was applied for sol synthesis. Then the mixture was under sonic treatment for the obtaining of viscous sol. The viscosity was determined by Brookfield HA/HB viscometer, and the surface tension by Kyowa DY-700 tensiometer. Aluminum oxide ink was deposited on polished slides (26×76 mm2, Paul Marienfeld, Germany, over titanium oxide layer. To print titania ink, we use a desktop office printer Canon Pixma IP 2840 and Dimatix DMP-2831. The thickness of an inkjet AlOOH layer after drying in the air and removal of the solvents did not exceed 150 nm with an RI not less than 1.35 in the entire visible range. Results. The stable colloidal ink was obtained for the first time on the base of aluminum oxide matrix with neutral pH. The rheology was regulated by controlling parameters of sol-gel method in the system of aqueous titanium dioxide sol and by adding ethanol that affects the charge of double electrical layer of disperse phase. The controllable coalesce of drops enables to apply antireflection coating within the thickness accuracy of 10 nm. The morphology of particles and the topology of printed structures were analyzed by optical, scanning electron and atomic-force microscopes. Practical Relevance. We have proposed the approach to obtain colorful, interference patterns using two types of high refractive inks with different refractive indexes. The inkjet printing method opens new opportunities for

EVALUACIÓN DEL SECADO DE PEREJIL APLICANDO TÉCNICAS DE DESHIDRATACIÓN OSMÓTICA COMO PRETRATAMIENTO EVALUATION OF PARSLEY DRYING APPLYING OSMOTIC DEHYDRATION TECHNIQUES AS PRETREATMENT

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Maribel García Mahecha

2010-12-01

Full Text Available En este estudio se evaluó el efecto de la temperatura de secado (50 y 60 °C y los diferentes tipos de pretratamientos (sin pretratamiento, deshidratación osmótica y deshidratación osmótica al vacío sobre las características fisicoquímicas y nutricionales del perejil deshidratado, midiendo la actividad de agua, densidad, rehidratación, color, contenido de vitamina C y carotenos. Los resultados mostraron que el secado de perejil a una temperatura de 60 °C sin pretratamiento es el más adecuado, presentando un menor tiempo de proceso (68 min, una mayor reducción en la humedad (4,3% y un menor efecto en los contenidos de vitamina C (8,7 mg de vitamina C/100 g de muestra y carotenos (36,9 mg de carotenos/100 g de muestra. Los procesos de secado con osmodeshidratación como pretratamiento son más lentos, debido a la formación de una capa de jarabe en la superficie de las muestras, la cual dificulta la salida de la humedad del interior de las hojas. El contenido de vitamina C disminuye en todos los procesos, pero es mayor en aquellos con pretratamiento por la solubilidad de la vitamina en el agua. Los carotenos se reducen en una mayor proporción en los procesos que toman mayor tiempo en llegar a la humedad de equilibrio debido a su termosensibilidad.The influence of the drying temperature (50 and 60 °C and the different pretreatments (without pretreatment, osmotic dehydration and vacuum osmotic dehydration were evaluated on the physical, chemical and nutritional characteristics of dried parsley, such as water activity, density, rehydration, color, vitamin C content, and carotene content. The results showed that drying at 60 °C without pretreatment is the best process for drying parsley because the process time (68 min and the moisture content (4,3% are lower and the vitamin C (8,7 mg vitamin C/100 g sample and carotene contents (36,9 mg carotene/100 g sample are less affected. The drying processes with osmodehydration as pretreatment

Simulación físico-matemática del secado de la zeolita con microondas. // Physical-mathematical simulation of the zeolite drying with microwaves.

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G. Quesada Ramos

2004-01-01

Full Text Available Se realiza una simulación físico-matemática del secado de la zeolita sometida a radiaciones de microondas utilizando la leyde Lambert. Las ecuaciones se expresan en un esquema implícito unidimensional, y se emplea el método numérico dediferencias finitas. La solución del sistema de ecuaciones se realiza por medio del método iterativo de Gauss-Seidel. Losresultados teóricos se comparan con los obtenidos experimentalmente.Palabras claves: Simulación, secado, zeolita, microondas._______________________________________________________________________________AbstractA physical-mathematical simulation of the zeolite drying with microwaves using the Lambert`s law is made. The equationsare expressed in an unidimensional implicit scheme, and the finite differences numeric method is used. The solution of theequations system is carried out by using the Gauss-Seidel´s iterativ method. The theoretical results are compared with thoseexperimentally obtained.Key words: Physical-mathematical simulation, drying, zeolite, microwaves.

Sol-gel-cum-hydrothermal synthesis of mesoporous Co-Fe@Al2O3 ...

Indian Academy of Sciences (India)

Oxides; sol-gel; adsorption; surface properties; composite materials. 1. Introduction. Industrial dyes ... acid green 25, Congo red, N719), phenolic compounds. (bromophenol blue .... microscopy (TEM) images were obtained using Philips CM.

Modelación del secado neumático vortiginoso del bagazo de la caña de azúcar//Modulation of sugar cane bagasse pneumatic drying in a vortex

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Eugenio F. Bombino-Matos

2013-09-01

Full Text Available Tomando en consideración los estudios realizados sobre la modelación del movimiento vortiginoso de partículas de bagazo, se realizó el estudio del secado neumático de esta importante biomasa teniendo en cuenta la transferencia de calor y de masa. Se modeló el proceso de secado a través de las ecuacionesfundamentales que describen la cinética del mismo y se compararon los resultados obtenidos con resultados reportados en la literatura especializada sobre mediciones de la variación del contenido de humedad en otros tipos de secadores neumáticos de bagazo para iguales condiciones de operación. Esta modelación permitió realizar simulaciones de este proceso las cuales arrojaron resultados aceptables en cuanto a los valores de disminución del contenido de humedad del bagazo lo que permitirá continuar profundizando en el desarrollo de próximos estudios sobre el tema ya que se evidencia que por esta vía es posible disminuir las dimensiones de los secadores de bagazo.Palabras claves: secado neumático vortiginoso, secado de bagazo, modelación matemática.______________________________________________________________________________AbstractTaking in account the studies carried out about the vortex movement of bagasse particles, the study of pneumatic drying of this important biomass was carried out considering the heat and mass transfer. The drying process was modeled through the fundamentals equations which describe the kinetic of it and theobtained results were compared with results reported in the specialized literature on drying measurements in others kinds of bagasse pneumatics dryers under the same conditions of operation. This modulation permitted to made simulations of this process which produced acceptable results about the decrease humidity values of bagasse and it will permit to continue in the development of next studies about this topic because it is evident that it is possible to reduce bagasse dryer dimensions.Key words

The structural studies of aluminosilicate gels and thin films synthesized by the sol-gel method using different Al2O3 and SiO2 precursors

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Adamczyk Anna

2015-12-01

Full Text Available Aluminosilicate materials were obtained by sol-gel method, using different Al2O3 and SiO2 precursors in order to prepare sols based on water and organic solvents. As SiO2 precursors, Aerosil 200TM and tetraethoxysilane TEOS: Si(OC2H54 were applied, while DisperalTM and aluminium secondary butoxide ATSB: Al(OC4H93 were used for Al2O3 ones. Bulk samples were obtained by heating gels at 500 °C, 850 °C and at 1150 °C in air, while thin films were synthesized on carbon, steel and alundum (representing porous ceramics substrates by the dip coating method. Thin films were annealed in air (steel and alundum and in argon (carbon at different temperatures, depending on the substrate type. The samples were synthesized as gels and coatings of the composition corresponding the that of 3Al2O3·2SiO2 mullite because of the specific valuable properties of this material. The structure of the annealed bulk samples and coatings was studied by FT-IR spectroscopy and XRD method (in standard and GID configurations. Additionally, the electron microscopy (SEM together with EDS microanalysis were applied to describe the morphology and the chemical composition of thin films. The analysis of FT-IR spectra and X-ray diffraction patterns of bulk samples revealed the presence of γ-Al2O3 and δ-Al2O3 phases, together with the small amount of SiO2 in the particulate samples. This observation was confirmed by the bands due to vibrations of Al–O bonds occurring in γ-Al2O3 and δ-Al2O3 structures, in the range of 400 to 900 cm−1. The same phases (γ-Al2O3 and δ-Al2O were observed in the deposited coatings, but the presence of particulate ones strongly depended on the type of Al2O3 and SiO2 precursor and on the heat treatment temperature. All thin films contained considerable amounts of amorphous phase.

Biocompatibility and Corrosion Protection Behaviour of Hydroxyapatite Sol-Gel-Derived Coatings on Ti6Al4V Alloy

Science.gov (United States)

El Hadad, Amir A.; Peón, Eduardo; García-Galván, Federico R.; Barranco, Violeta; Parra, Juan; Jiménez-Morales, Antonia; Galván, Juan Carlos

2017-01-01

The aim of this work was to prepare hydroxyapatite coatings (HAp) by a sol-gel method on Ti6Al4V alloy and to study the bioactivity, biocompatibility and corrosion protection behaviour of these coatings in presence of simulated body fluids (SBFs). Thermogravimetric/Differential Thermal Analyses (TG/DTA) and X-ray Diffraction (XRD) have been applied to obtain information about the phase transformations, mass loss, identification of the phases developed, crystallite size and degree of crystallinity of the obtained HAp powders. Fourier Transformer Infrared Spectroscopy (FTIR) has been utilized for studying the functional groups of the prepared structures. The surface morphology of the resulting HAp coatings was studied by Scanning Electron Microscopy (SEM). The bioactivity was evaluated by soaking the HAp-coatings/Ti6Al4V system in Kokubo’s Simulated Body Fluid (SBF) applying Inductively Coupled Plasma (ICP) spectrometry. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and Alamar blue cell viability assays were used to study the biocompatibility. Finally, the corrosion behaviour of HAp-coatings/Ti6Al4V system was researched by means of Electrochemical Impedance Spectroscopy (EIS). The obtained results showed that the prepared powders were nanocrystalline HAp with little deviations from that present in the human bone. All the prepared HAp coatings deposited on Ti6Al4V showed well-behaved biocompatibility, good bioactivity and corrosion protection properties. PMID:28772455

Biocompatibility and Corrosion Protection Behaviour of Hydroxyapatite Sol-Gel-Derived Coatings on Ti6Al4V Alloy

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Amir A. El Hadad

2017-01-01

Full Text Available The aim of this work was to prepare hydroxyapatite coatings (HAp by a sol-gel method on Ti6Al4V alloy and to study the bioactivity, biocompatibility and corrosion protection behaviour of these coatings in presence of simulated body fluids (SBFs. Thermogravimetric/Differential Thermal Analyses (TG/DTA and X-ray Diffraction (XRD have been applied to obtain information about the phase transformations, mass loss, identification of the phases developed, crystallite size and degree of crystallinity of the obtained HAp powders. Fourier Transformer Infrared Spectroscopy (FTIR has been utilized for studying the functional groups of the prepared structures. The surface morphology of the resulting HAp coatings was studied by Scanning Electron Microscopy (SEM. The bioactivity was evaluated by soaking the HAp-coatings/Ti6Al4V system in Kokubo’s Simulated Body Fluid (SBF applying Inductively Coupled Plasma (ICP spectrometry. 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT and Alamar blue cell viability assays were used to study the biocompatibility. Finally, the corrosion behaviour of HAp-coatings/Ti6Al4V system was researched by means of Electrochemical Impedance Spectroscopy (EIS. The obtained results showed that the prepared powders were nanocrystalline HAp with little deviations from that present in the human bone. All the prepared HAp coatings deposited on Ti6Al4V showed well-behaved biocompatibility, good bioactivity and corrosion protection properties.

Effect of the Mg/Al Ratio on Activated Sol-Gel Hydrotalcites for Photocatalytic Degradation of 2,4,6-Trichlorophenol

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Esthela Ramos-Ramírez

2017-01-01

Full Text Available Currently, interest has grown in finding effective solutions for the treatment of water pollution by toxic compounds. Some of the latter that have acquired importance are phenols and chlorophenols, due to their employment in the manufacture of pesticides, insecticides, cords of wood, paper industry, among others. The problem is rooted in that these compounds are very persistent in the environment because they are partially biodegradable and cannot be photodegraded directly by sunlight. Chlorophenols are extremely toxic, especially 2,4,6-trichlorophenol, which is potentially carcinogenic. In this work, Mg/Al-mixed oxide catalysts were obtained from the thermal treatment of hydrotalcite-type materials, synthesized by sol-gel method with different Mg/Al ratios. Hydrotalcites and Mg/Al-mixed oxides were physicochemically characterized by X-ray diffraction, thermal analysis (DTA and TGA, and N2 physisorption. The results were obtained on having proven the photocatalytic degradation of 2,4,6-trichlorophenol as a pollutant model by water. The catalysts obtained present the hydrotalcite phase with thermal evolution until achieving Mg/Al-mixed oxides at 500°C. The catalysts are of mesoporous materials and exhibiting large surface areas. The catalysts demonstrated good photocatalytic activity with good efficiency, reaching degradation percentages with Mg/Al = 1, 2, 4, 5, and 7 ratios of 94.2, 92.5, 86.2, 84.2, and 63.9%, respectively, until achieving mineralization.

SECAFÉ Parte I: modelamiento y simulación matemática en el secado mecánico de café pergamino SECAFÉ Part I: modeling and mathematical simulation in the mechanical drying of parchment coffee

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Alfonso Parra-Coronado

2008-08-01

Full Text Available Se implementó en lenguaje de programación Microsoft Visual Basic 6.0, dos programas de simulación matemática para el secado de café pergamino, tomando como base los modelos de Thompson y de la Universidad del Estado de Michigan (MSU, para lo cual se utilizaron los parámetros determinados en Cenicafé para la simulación matemática del secado de café pergamino. Los programas estiman el funcionamiento de cada uno de los secadores mecánicos de café existentes en Colombia. Se compararon los resultados obtenidos mediante simulación para cada uno de los secadores, con los resultados experimentales obtenidos en Cenicafé, concluyéndose que éstos predicen adecuadamente el secado del café pergamino. Con base en los buenos resultados de la evaluación de los programas, se implementó un único programa de simulación para el secado de café pergamino.A Microsoft Visual Basic 6.0 parchment coffee drying program was implemented. Two separate programs, based on the Thompson and Michigan State University (MSU models, using Cenicafé coffee parameters, were successfully tested for the evaluation of the performance of all mechanical coffee dryers existing in Colombia. The results obtained by means of simulation for each one of the dryers were compared with the experimental results obtained in Cenicafé, resulting in the conclusion that these suitably predict the drying of the coffee parchment. Based on the good results obtained, a unique simulation program was implemented for drying parchment coffee.

Intermittent Coffee Drying in Deep Bed with Pulsed Airflow Secado de Café en Lecho Fijo con Intermitencia Térmica y Flujo de Aire Pulsado

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Héctor José Ciro Velásquez

2011-12-01

Full Text Available A dryer in deep bed without airflow reversal was adapted to work simultaneously with thermal intermittence and pulsed airflow in the drying of parchment coffee bean. The dryer was operated by cycles of thermal intermittence for a heating temperature of 55 °C and cooling of 40 and 25 °C. The results showed that the increase of temperature in the cycle of cooling tends to increase the water removal and that the increase of the number of air pulses without reversal of the direction of air flow causes an excessive moisture gradient within the batch. Moreover, the specific energy requirement of the dryer was from 15 to 25 MJ/kg, showing the best thermal performance for the condition in which the dryer was operate without pulsed airflow.Un secador de lecho fijo fue adaptado para trabajar de forma simultánea con intermitencia térmica y flujo de aire pulsado sin inversión de flujo de aire, en el secado de granos de café. El secador fue operado con ciclos de intermitencia térmica para una temperatura de calentamiento de 55 °C y enfriamiento de 40 y 25 °C. Los resultados mostraron que el aumento de temperatura en el ciclo de enfriamiento, tiende a incrementar la remoción de agua y que el aumento del número de pulsos de aire sin inversión del flujo de dirección del aire, ocasiona un secado deficiente debido al excesivo gradiente de humedad ocasionado en la capa de producto. Adicionalmente, se encontró que el consumo de energía específica del secador varió entre 15 y 25 MJ/kg de agua evaporada, siendo el mejor rendimiento termo energético para la condición en la cual el secador fue operado sin flujo de aire pulsado.

Variation in Structural and Optical Properties of Al Doped ZnO Nanoparticles Synthesized by Sol-gel Process

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Vanaja Aravapalli

2017-04-01

Full Text Available This article focuses on analyzing structural and optical properties of Al doped ZnO (AZO synthesized with two different precursors aluminum chloride and aluminum nitrate. The nanoparticles were successfully fabricated and characterized at room temperature by sol-gel process. The objective of improving properties of ZnO nanoparticles by introducing dopants was successful with formation of nanoparticles having different crystalline sizes, optical absorption and luminescence properties. The two different sources influenced properties of ZnO. The particles with less crystalline size obtained from aluminum nitrate. Change in morphology from spherical to bar like morphology proved from SEM spectra. Presence of functional groups predicted from FTIR spectra. PL spectra proved UV emission and visible emission for AZO nanoparticles synthesized using dopant sources aluminum chloride and aluminum nitrate respectively. The obtained properties prove successful utilization of AZO nanoparticles as building materials in fabrication of optoelectronic devices.

The zinc fingers of the Small Optic Lobes (SOL) calpain bind polyubiquitin.

Science.gov (United States)

Hastings, Margaret H; Qiu, Alvin; Zha, Congyao; Farah, Carole A; Mahdid, Yacine; Ferguson, Larissa; Sossin, Wayne S

2018-05-28

The Small Optic Lobes (SOL) calpain is a highly conserved member of the calpain family expressed in the nervous system. A dominant negative form of the SOL calpain inhibited consolidation of one form of synaptic plasticity, non-associative facilitation, in sensory-motor neuronal cultures in Aplysia, presumably by inhibiting cleavage of protein kinase Cs (PKCs) into constitutively active protein kinase Ms (PKMs) (Hu et al, 2017a). SOL calpains have a conserved set of 5-6 N-terminal zinc fingers. Bioinformatic analysis suggests that these zinc fingers could bind to ubiquitin. In this study, we show that both the Aplysia and mouse SOL calpain (also known as Calpain 15) zinc fingers bind ubiquitinated proteins, and we confirm that Aplysia SOL binds poly- but not mono or di-ubiquitin. No specific zinc finger is required for polyubiquitin binding. Neither polyubiquitin nor calcium was sufficient to induce purified Aplysia SOL calpain to autolyse or to cleave the atypical PKC to PKM in vitro. In Aplysia, overexpression of the atypical PKC in sensory neurons leads to an activity-dependent cleavage event and an increase in nuclear ubiquitin staining. Activity-dependent cleavage is partially blocked by a dominant negative SOL calpain, but not by a dominant negative classical calpain. The cleaved PKM was stabilized by the dominant negative classical calpain and destabilized by a dominant negative form of the PKM stabilizing proteinKIdney/BRAin protein(KIBRA). These studies provide new insight into SOL calpain's function and regulation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports.

Science.gov (United States)

Yaakob, Zahira; Bshish, Ahmed; Ebshish, Ali; Tasirin, Siti Masrinda; Alhasan, Fatah H

2013-05-30

Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/Al S.G. ) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/Al S.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/Al S.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.

Metal-silica sol-gel materials

Science.gov (United States)

Stiegman, Albert E. (Inventor)

2002-01-01

The present invention relates to a single phase metal-silica sol-gel glass formed by the co-condensation of a transition metal with silicon atoms where the metal atoms are uniformly distributed within the sol-gel glass as individual metal centers. Any transition metal may be used in the sol-gel glasses. The present invention also relates to sensor materials where the sensor material is formed using the single phase metal-silica sol-gel glasses. The sensor materials may be in the form of a thin film or may be attached to an optical fiber. The present invention also relates to a method of sensing chemicals using the chemical sensors by monitoring the chromatic change of the metal-silica sol-gel glass when the chemical binds to the sensor. The present invention also relates to oxidation catalysts where a metal-silica sol-gel glass catalyzes the reaction. The present invention also relates to a method of performing oxidation reactions using the metal-silica sol-gel glasses. The present invention also relates to organopolymer metal-silica sol-gel composites where the pores of the metal-silica sol-gel glasses are filled with an organic polymer polymerized by the sol-gel glass.

Effect of the crystallinity in the Tl signal induced by the gamma radiation in Al{sub 2}O{sub 3}: Eu obtained by the sol gel method; Efecto de la cristalinidad en la senal Tl inducida por la radiacion gamma en Al{sub 2}O{sub 3}: Eu obtenida por el metodo sol gel

Energy Technology Data Exchange (ETDEWEB)

Mendoza A, D.; Gonzalez M, P.R. [ININ, Gerencia de Ciencias de Materiales. Carr. Mexico-Toluca Km. 36.5, 52045 Ocoyoacac (Mexico); Custodio, E. [Universidad Juarez Autonoma de Tabasco, DACB, Carr. Cunduacan-Jalpa, km. 1.5, 86680 Tabasco (Mexico); Rubio, E.; Rodriguez L, V. [Facultad de Ingenieria Quimica, BUAP. Av. San Claudio y 18 Sur Col. San Manuel. C. P. 72570.C.U. Puebla (Mexico)

2004-07-01

In this work the synthesis and characterization process of Al{sub 2}O{sub 3} and Al{sub 2}O{sub 3}: Eu by sol gel method is reported. A previous thermal treatment at 500 and 1000 C on the material powder type showed a notable influences on the thermoluminescent signal induced by the gamma radiation, such that the intensity thermoluminescent signal produced by samples with thermal treatment at 1000 C is much bigger that thermoluminescent signal produced by samples thermal treatment at 500 C. In order to explain this behavior, an analysis for X-ray diffraction and electron microscopy was also realized. The results show a notably influence of the crystalline array and the microstructure on the thermoluminescent behavior of the alumina. (Author)

Thoria sol-gel processes

International Nuclear Information System (INIS)

Matthews, R.B.

1978-10-01

Alternate fuel fabrication techniques are being developed at WNRE as part of the thorium fuel cycle program. The sol-gel techniques are attractive and this report assembles and summarizes information relating to thoria sol-gel fuels. Some background information on the behaviour and advantages of sol-gel fuel forms is presented, followed by a review of relevant colloid chemistry and an explanation of the fundamental steps of sol-gel processes. Finally, several variants to the basic process are reviewed and evaluated. (author)

Effect of the crystallinity in the Tl signal induced by the gamma radiation in Al2O3: Eu obtained by the sol gel method

International Nuclear Information System (INIS)

Mendoza A, D.; Gonzalez M, P.R.; Custodio, E.; Rubio, E.; Rodriguez L, V.

2004-01-01

In this work the synthesis and characterization process of Al 2 O 3 and Al 2 O 3 : Eu by sol gel method is reported. A previous thermal treatment at 500 and 1000 C on the material powder type showed a notable influences on the thermoluminescent signal induced by the gamma radiation, such that the intensity thermoluminescent signal produced by samples with thermal treatment at 1000 C is much bigger that thermoluminescent signal produced by samples thermal treatment at 500 C. In order to explain this behavior, an analysis for X-ray diffraction and electron microscopy was also realized. The results show a notably influence of the crystalline array and the microstructure on the thermoluminescent behavior of the alumina. (Author)

TURISMO Y CUERPOS DESNUDOS Moda y culto al sol en el litoral marítimo argentino

Directory of Open Access Journals (Sweden)

Regina Schlüter

2010-09-01

Full Text Available Normal 0 21 false false false PT-BR X-NONE X-NONE MicrosoftInternetExplorer4 Resumen: Los cambios en la estructura social que se observaron en Argentina después de la Primera Guerra Mundial le dieron a la mujer una mayor libertad de acción permitiéndole ingresar en el campo laboral, practicar deportes y participar del turismo. Esto tuvo un gran impacto en la moda de la época y modificó las formas de socialización lo que se observa en los destinos de sol y playa de la época. La vestimenta femenina que se caracterizaba por una extrema formalidad que no dejaba nada al descubierto fue dejando a la vista cada vez mayores partes del cuerpo y se comenzó a priorizar la comodidad. También la moda del bronceado jugó un rol preponderante en las costumbres de la época ya que se convirtió en un elemento importante de diferenciación social.

Preparation and characterization of sol-gel derived 4%La{sub 2}O{sub 3}-Al{sub 2}O{sub 3} ceramic membrane on clay-based supports

Energy Technology Data Exchange (ETDEWEB)

Ersoy, B. [Afyon Kocatepe Univ., Mining Engineering Dept., AFYON (Turkey); Gunay, V. [TUBITAK-MRC, MCTRI, Gebze-KOCAELI (Turkey)

2004-07-01

In this work, {gamma}-Al{sub 2}O{sub 3} membrane layer (4 wt% La{sub 2}O{sub 3}+96% Al{sub 2}O{sub 3}) was coated on the clay based porous support by using the sol-gel coating. The coating solution was prepared by using boehmite (AlOOH), La-nitrate (La{sub 2}(NO{sub 3}){sub 3}.6H{sub 2}O), PVA, distilled water and HNO{sub 3}. The thickness of the {gamma}-Al{sub 2}O{sub 3} membrane layer was between 5-7 {mu}m. Two unprocessed clay samples which were supplied from Kutahya and Balikesir regions, were used to produce supports for the membranes. Porosities of the supports were varied from 25 to 40% depending on sintering temperatures. Mean pore diameter of the supports were between 0.01-1{mu}m. The mean pore diameter of 4wt%La{sub 2}O{sub 3} - Al{sub 2}O{sub 3} membrane layer was around 11 nm and total pore area was 113 m{sup 2} / g at 1000 C for 1 hour. (orig.)

Expedition sol

DEFF Research Database (Denmark)

Jacobsen, Aase Roland

2006-01-01

Tag på expedition sol rundt i museet. Er der nogen, der har taget en bid af solen? Hvorfor bliver der solformørkelse? Kan vi undvære Solen?......Tag på expedition sol rundt i museet. Er der nogen, der har taget en bid af solen? Hvorfor bliver der solformørkelse? Kan vi undvære Solen?...

Synthesis of Copper-Based Transparent Conductive Oxides with Delafossite Structure via Sol-Gel Processing

OpenAIRE

Götzendörfer, Stefan

2011-01-01

Starting off with solubility experiments of possible precursors, the present study reveals the whole development of a sol gel processing route for transparent p type semiconductive thin films with delafossite structure right to the fabrication of functional p-n junctions. The versatile sol formulation could successfully be modified for several oxide compositions, enabling the synthesis of CuAlO2, CuCrO2, CuMnO2, CuFeO2 and more. Although several differences in the sintering behaviour of powde...

Fabrication of silica glass containing yellow oxynitride phosphor by the sol-gel process

Energy Technology Data Exchange (ETDEWEB)

Segawa, Hiroyo; Yoshimizu, Hisato; Hirosaki, Naoto; Inoue, Satoru, E-mail: SEGAWA.Hiroyo@nims.go.jp [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

2011-06-15

We have prepared silica glass by the sol-gel method and studied its ability to disperse the Ca-{alpha}-SiAlON:Eu{sup 2+} phosphor for application in white light emitting diodes (LEDs). The emission color generated by irradiating doped glass with a blue LED at 450 nm depended on the concentration of SiAlON and the glass thickness, resulting in nearly white light. The luminescence efficiency of 1-mm-thick glass depended on the SiAlON concentration, and was highest at 4 wt% SiAlON.

Influencia del secado lento a baja temperatura en el contenido carotenoide de dos variedades de pimiento (Capsicum annuum L.. Balance biosintético y/o degradativo en función de las condiciones de procesado

Directory of Open Access Journals (Sweden)

Minguez-Mosquera, M. I.

2001-10-01

Full Text Available A study of drying process at low temperature of two varieties of pepper for paprika (Capsicum annuum L. cv Jaranda and Jariza according to the traditional techniques of La Vera region is carried out controlling simultaneously the characteristics of the fruits before and after of the dehydration process and the conditions used. Correspondences have been found between the initial moisture of the fruits, the drying parameters (temperature and time, and the increase and/or loss (including its corresponding quantity in carotenoid pigment content. The favorable conditions to produce a pigment content increase, that indicates the existence of a biosynthetic process, are those including a healthy raw material with high moisture values and temperature of dried moderate - low (50 ºC without extending unnecessarily the dehydration time (just to obtain the adequate texture for the grinding.Se realiza un estudio del proceso de secado de dos variedades de pimiento pimentonero (Capsicum annuum L. cv Jaranda y cv Jariza efectuado a baja temperatura según las técnicas tradicionales de la comarca de La Vera. El control de las características de los frutos antes y después del procesado y de las condiciones de deshidratación en seis procesos de secado han permitido establecer una correspondencia entre la humedad inicial de los frutos, los parámetros de secado (temperatura y tiempo, y la ganancia y/o pérdida (y su correspondiente cuantía en el contenido inicial de pigmentos carotenoides. Las condiciones favorables a una ganancia en pigmentos (que indica la existencia de un proceso biosintético son aquellas en las que se parte de frutos sanos, con altos valores de humedad, temperatura de secado moderada - baja (menor de 50 ºC y sin extender innecesariamente el tiempo de procesado (sólo hasta conseguir la textura adecuada para la molienda.

Sol-gel synthesis and characterization of fine-grained ceramics in the alumina-titania system

Energy Technology Data Exchange (ETDEWEB)

Otterstein, E. [Institute of Physics, University of Rostock, August-Bebel-Strasse 55, 18055 Rostock (Germany)], E-mail: otterstein@physik1.uni-rostock.de; Karapetyan, G. [Institute of Chemistry, University of Rostock, Albert-Einstein-Strasse 3a, 18059 Rostock (Germany); Nicula, R. [Institute of Physics, University of Rostock, August-Bebel-Strasse 55, 18055 Rostock (Germany); Stir, M. [Institute of Physics, University of Rostock, August-Bebel-Strasse 55, 18055 Rostock (Germany); National Institute for Materials Physics, 105b Atomistilor Strasse, P.O.B. MG7, 077125 Bucharest-Magurele (Romania); Schick, C. [Institute of Physics, University of Rostock, Universitaetsplatz 3, 18051 Rostock (Germany); Burkel, E. [Institute of Physics, University of Rostock, August-Bebel-Strasse 55, 18055 Rostock (Germany)

2008-02-05

Fine-grained ceramics of the Al{sub 2}O{sub 3}-TiO{sub 2} system were synthesised by reactive sintering of sol-gel precursors (Al- and Ti-alkoxides). The thermal behaviour of the as-prepared xerogels was examined by thermal analysis and X-ray powder diffraction. Preliminary results concerning powder consolidation into bulk ceramic parts using spark plasma sintering (SPS) are discussed.

Influence of osmotic pre-treatment on convective drying of yellow pitahaya

Directory of Open Access Journals (Sweden)

Alfredo Ayala-Aponte

2014-01-01

Full Text Available Cilindros de pitahayas fueron osmóticamente deshidratados en sa carosa 55 % (p/p durante 45 minutos como un pre-tratamiento al secado convectivo. El secado por aire caliente se realizó a 50, 60 y 70ºC. Se comparó la cinética de secado de las muestras osmodeshidratadas con las muestras no tratadas. Se determinaron los coeficientes de difusión efectiva. Los valores de la energ ía de activación fueron 29.56 y 16.93 kJ mol -1 para las muestras pre-tratadas y para las no tratadas, respect ivamente. Se aplicó modelado matemático para simular las curvas experimentales de secado de las pitahayas. Los resultados indicaron que el modelo de Weibul l podría ser usado para simular los datos de secado experimental. Además , el encogimiento de las muestras debido a cambios en el volume n fue más pronunciado en las muestras sin pretratar.

Sol-Gel Derived Hafnia Coatings

Science.gov (United States)

Feldman, Jay D.; Stackpoole, Mairead; Blum, Yigal; Sacks, Michael; Ellerby, Don; Johnson, Sylvia M.; Venkatapathy, Ethiras (Technical Monitor)

2002-01-01

Sol-gel derived hafnia coatings are being developed to provide an oxidation protection layer on ultra-high temperature ceramics for potential use in turbine engines (ultra-efficient engine technology being developed by NASA). Coatings using hafnia sol hafnia filler particles will be discussed along with sol synthesis and characterization.

Sol-gel technology for biomedical engineering

International Nuclear Information System (INIS)

Podbielska, H.; Ulatowska-Jarza, A.

2005-01-01

Sol-gel derived silica possess many promising features, including low-temperature preparation procedure, porosity, chemical and physical stability. Applications exploiting porous materials to encapsulate sensor molecules, enzymes and many other compounds, are developing rapidly. In this paper some potential applications, with emphasis on biomedical and environmental ones, are reviewed. The material preparation procedure is described and practical remarks on silica-based sol-gels are included. It is reported that sol-gels with entrapped various molecules may be used in construction of implants and coatings with bioactive properties. It is shown how to exploit the sol-gel production route for construction of sol-gel coated fiberoptic applicators for laser therapy. The applications of bioactive materials are discussed, as well. It is demonstrated that it is possible to immobilize photosensitive compounds in sol-gel matrix without loosing their photoactivity. Some examples of sol-gel based biosensors are demonstrated, as well, showing their potential for detecting various gases, toxic substances, acidity, humidity, enzymes and biologically active agents. (authors)

Compacting and crystallisation of transparent conductive oxidic sol-gel layers as illustrated by the example of zinc oxide; Verdichtung und Kristallisation von transparenten leitfaehigen oxidischen Sol-gel-Schichten am Beispiel des Zinkoxids

Energy Technology Data Exchange (ETDEWEB)

Schuler, T.

2003-07-01

flux (Al2O3 in ZnO:Al). (orig.) [German] In dieser Arbeit wurde gezeigt, dass ueber das preiswerte Sol-Gel-Tauchbeschichtungsverfahren dotierte Zinkoxid-Beschichtungen auf Glas hergestellt werden koennen. Der niedrigste erreichte spezifische Widerstand betraegt 1.1x10{sup -3}ohmcm fuer Mehrfach-Schichten aus Aluminium-dotiertem Zinkoxid. Es wurde gezeigt, dass fuer dicke Schichten die Kristallitgroesse von der Dotierung des Sols, der Temperatur und der Sinterzeit abhaengt, waehrend die Schichtdicke selbst massgeblich von der Konzentration der Loesung (Viskositaet) und der Ziehgeschwindigkeit bestimmt wird. Auf dieser Grundlage entstand ein Modell fuer die beobachteten Strukturen, das auch fuer andere Sol-Gel-Schichten anwendbar ist. Ueber den Prozessparameter p der Gleichung ESD = p x IKG kann so die Morphologie von Mehrfach-Schichten festgelegt werden. Der Strukturuebergang von der koernigen Struktur zur Lagen-Struktur wurde fuer p = 2.4 bis 3 und fuer den Uebergang von der Lagen-Struktur zur kolumnaren Struktur fuer p=1 festgelegt. Das vorgeschlagene Modell empfiehlt sich durch den Vergleich mit der Spruehpyrolyse auch als Prototypmodell fuer das Schichtwachstum dieser Technologie und kann darueber hinaus vermutlich auch auf physikalische Beschichtungstechnologien ausgeweitet werden. Die beobachtete Morphologie wirkt sich ueber die entstehenden Korngrenzen und die erreichte Verdichtung auf die elektrischen und damit auch auf die optischen Eigenschaften der Schichten aus. Mit steigender Verdichtung, sinkt folglich der spezifische Widerstand der Schicht. Es wurde demonstriert, dass die Beschichtungstemperatur durch Verringern der Einzelschichtdicke von 550 deg C auf 450 deg C verringert werden kann, ohne die Leitfaehigkeit zu verschlechtern. Zudem wurden Moeglichkeiten aufgezeigt, mittels anderer Sintertechnologien, wie dem pyrolytischen Gasflammen-Sintern und dem Laser-Sintern die Schichteigenschaften zu verbessern bzw. die Prozesszeit zu minimieren. Als groesstes

Empleo del método de secado convectivo combinado para la deshidratación de papaya (Carica papaya L.), variedad Maradol roja

OpenAIRE

Sahylin Muñiz Becerá; Antihus Hernández Gómez; Annia García Pereira; Lilia Méndez Lagunas

2013-01-01

La presente investigación tiene como objetivo evaluar el método de secado convectivo de papaya (Carica papaya L.) variedad Maradol roja, combinado con la aplicación de pretratamientos de osmosis (DOSC) y escaldado simple (ESSC), mediante el efecto de los factores tecnológi- cos del secador: temperatura (40 y 60oC) y velocidad del flujo de aire (2,5 y 1,5 m/s) sobre el comportamiento de las propiedades de calidad de la fruta deshidratada y la cinética del proceso. El pretratamiento de escaldad...

Gestion participative de la fertilite de sol en culture biologique d ...

African Journals Online (AJOL)

Ananas comosus dans un dispositif en blocs aléatoires avec 2 répétitions sur des parcelles élémentaires de 20 m² avec trois niveaux de doses de fientes de poulets et quatre doses de sulfate de potassium. Le sol a été analysé avant et après ...

Hybrid sol-gel optical materials

Science.gov (United States)

Zeigler, John M.

1992-01-01

Hybrid sol-gel materials comprise silicate sols cross-linked with linear polysilane, polygermane, or poly(silane-germane). The sol-gel materials are useful as optical identifiers in tagging and verification applications and, in a different aspect, as stable, visible light transparent non-linear optical materials. Methyl or phenyl silicones, polyaryl sulfides, polyaryl ethers, and rubbery polysilanes may be used in addition to the linear polysilane. The linear polymers cross-link with the sol to form a matrix having high optical transparency, resistance to thermooxidative aging, adherence to a variety of substrates, brittleness, and a resistance to cracking during thermal cycling.

Efecto del secado en ambiente de servicio en la evolución de las propiedades mecánicas de hormigones livianos estructurales Effect of drying under service environment on the mechanical properties of structural lightweight concretes

Directory of Open Access Journals (Sweden)

Carlos Videla

2007-08-01

Full Text Available En este trabajo se evalúa el efecto de la humedad relativa del ambiente de servicio en las resistencias a compresión y a tracción y en el módulo de elasticidad de hormigones livianos estructurales. Además se establecen relaciones que permiten estimar estas propiedades en función de la humedad relativa del ambiente y del tiempo de secado. Los hormigones se fabricaron con dos tipos de áridos gruesos livianos, piedra pómez y pellets de ceniza volante, y con un árido fino de densidad normal. Los hormigones se sometieron a dos condiciones ambientales de servicio: una a 90% de humedad relativa y otra a 90% de humedad relativa durante los 7 primeros días y luego a 50% de humedad relativa hasta la edad de ensayo. Los ensayos se efectuaron a 7, 28, 60 y 90 días de edad. Se observó un deterioro importante de las propiedades medidas por efecto de las condiciones de secado; a 83 días de secado, en promedio las pérdidas de resistencia a tracción y compresión fueron de 20% y 15%, respectivamente, y de módulo de elasticidad de 40% respecto a hormigones a 90% de humedad relativa. Se concluye que hay dos variables principales que regulan el efecto del secado en el hormigón liviano. La primera de éstas corresponde a razón agua-cemento y que define entre otras cosas la permeabilidad de la fase resistente. La otra variable corresponde al contenido relativo de árido liviano en la mezclaIn this paper the effect of the ambient relative humidity at service on the compressive and splitting strengths and in the modulus of elasticity of structural lightweight concretes is evaluated. Also, relationships are proposed allowing estimating these properties as a function of the ambient relative humidity and drying time. The concretes were made with two types of coarse lightweight aggregates, pumice and fly ash pellets, and with normal density fine aggregate. The concretes were subjected to two different environmental service conditions: 90% relative

Preparation and characterization of multi-walled carbon nanotube/hydroxyapatite nanocomposite film dip coated on Ti-6Al-4V by sol-gel method for biomedical applications: an in vitro study.

Science.gov (United States)

Abrishamchian, Alireza; Hooshmand, Tabassom; Mohammadi, Mohammadreza; Najafi, Farhood

2013-05-01

In the present research, the introduction of multi-walled carbon nanotubes (MWCNTs) into the hydroxyapatite (HA) matrix and dip coating of nanocomposite on titanium alloy (Ti-6Al-4V) plate was conducted in order to improve the performance of the HA-coated implant via the sol-gel method. The structural characterization and electron microscopy results confirmed well crystallized HA-MWCNT coating and homogenous dispersion of carbon nanotubes in the ceramic matrix at temperatures as low as 500 °C. The evaluation of the mechanical properties of HA and HA/MWCNT composite coatings with different weight percentages of MWCNTs showed that the addition of low concentrations of MWCNTs (0.5 and 1 wt.%) had improved effect on the mechanical properties of nanocomposite coatings. Moreover, this in vitro study ascertained the biocompatibility of the prepared sol-gel-derived HA/MWCNT composite coatings. Copyright © 2013 Elsevier B.V. All rights reserved.

La Sisactía de Solón y el juramento de los heliastas

OpenAIRE

Valdés Guía, Miriam

1999-01-01

La liberación del demos ateniense, sumido en una situación de dependencia y progresiva esclavización en Atenas arcaica, se asoció, con Solón, al culto a un dios, Zeus con el epíteto Eleutherios, y se garantizó mediante el establecimiento de las nuevas leyes y de la Heliea, cuyos miembros realizaban un juramento, instaurado en estos momentos, en el que significativamente se incluye también a Zeus con el epíteto Basileus (protector de las leyes en la poesía de Solón), junto a Apolo Patroos y D...

Effect of sol concentration on the properties of ZnO thin films prepared by sol-gel technique

International Nuclear Information System (INIS)

Dutta, M.; Mridha, S.; Basak, D.

2008-01-01

ZnO thin films are deposited on the glass substrates by sol-gel drain coating technique by varying the concentration of the sol. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were used to investigate the effect of sol concentration on the crystallinity and surface morphology of the films. The results show that with increase in sol concentration, the value of full width at half maximum (FWHM) of (0 0 2) peak decreases while the strain first increases and then decreases. The sol with higher concentration results in the increase in the grain size. The studies on the optical properties show that the band gap value increases from 3.27 to 3.3 eV when the sol concentration changes from 0.03 to 0.1 M. The photoconductivity studies reveal that the film for 0.05 M sol shows the maximum photoresponse for ultraviolet (UV) wavelength (<400 nm) which is co-related with the deep-level defects. The growth and decay of the photocurrent is found to be slowest for the same film

Synthesis of Sol-Gel Precursors for Ceramics from Lunar and Martian Soil Simulars

Science.gov (United States)

Sibille, L.; Gavira-Gallardo, J. A.; Hourlier-Bahloul, D.

2004-01-01

Recent NASA mission plans for the human exploration of our Solar System has set new priorities for research and development of technologies necessary to enable a long-term human presence on the Moon and Mars. The recovery and processing of metals and oxides from mineral sources on other planets is under study to enable use of ceramics, glasses and metals by explorer outposts. We report initial results on the production of sol-gel precursors for ceramic products using mineral resources available in martian or lunar soil. The presence of SO2, TiO2, and Al2O3 in both martian (44 wt.% SiO2, 1 wt.% TiO2, 7 wt.% Al2O3) and lunar (48 wt.% SiO2, 1.5 wt.% TiO2, 16 wt.% Al2O3) soils and the recent developments in chemical processes to solubilize silicates using organic reagents and relatively little energy indicate that such an endeavor is possible. In order to eliminate the risks involved in the use of hydrofluoric acid to dissolve silicates, two distinct chemical routes are investigated to obtain soluble silicon oxide precursors from lunar and martian soil simulars. Clear solutions of sol-gel precursors have been obtained by dissolution of silica from lunar soil similar JSC-1 in basic ethylene glycol (C2H4(OH)2) solutions to form silicon glycolates. Similarly, sol-gel solutions produced from martian soil simulars reveal higher contents of iron oxides. Characterization of the precursor molecules and efforts to further concentrate and hydrolyze the products to obtain gel materials will be presented for evaluation as ceramic precursors.

Synthesis of Sol-Gel Precursors for Ceramics from Lunar and Martian Soil Simulars

Science.gov (United States)

Sibille, L.; Gavira-Gallardo, J. A.; Hourlier-Bahloul, D.

2003-01-01

Recent NASA mission plans for the human exploration of our Solar System has set new priorities for research and development of technologies necessary to enable a long-term human presence on the Moon and Mars. The recovery and processing of metals and oxides from mineral sources on other planets is under study to enable use of ceramics, glasses and metals by explorer outposts. We report initial results on the production of sol-gel precursors for ceramic products using mineral resources available in martian or lunar soil. The presence of SiO2, TiO2, and Al2O3 in both martian (44 wt.% SiO2, 1 wt.% TiO2,7 wt.% Al2O3) and lunar (48 wt.% SiO2, 1.5 wt.% TiO2, 16 wt.% Al2O3) soils and the recent developments in chemical processes to solubilize silicates using organic reagents and relatively little energy indicate that such an endeavor is possible. In order to eliminate the risks involved in the use of hydrofluoric acid to dissolve silicates, two distinct chemical routes are investigated to obtain soluble silicon oxide precursors from lunar and martian soil simulars. Clear solutions of sol-gel precursors have been obtained by dissolution of silica from lunar soil simular in basic ethylene glycol (C2H4(OH)2) solutions to form silicon glycolates. Similarly, sol-gel solutions produced from martian soil simulars reveal higher contents of iron oxides. The elemental composition and structure of the precursor molecules were characterized. Further concentration and hydrolysis of the products was performed to obtain gel materials for evaluation as ceramic precursors.

Incremento de disolución de un derivado del furano mediante la técnica de secado por atomización Improvement of Furane derivate dissolution rate using spray drying technique

Directory of Open Access Journals (Sweden)

Antonio Iraizoz Barrios

2012-06-01

Full Text Available Objetivo: incrementar la solubilidad en agua del 2-bromo-5-(2-bromo-2-nitrovinyl-furano (G1, un ingrediente farmacéuticamente activo sintetizado por el Centro de Bioactivos Químicos de la Universidad Central de Las Villas, con potente acción bactericida y fungicida, mediante la elaboración de macropartículas de dispersiones sólidas utilizando un proceso de secado por atomización. Métodos: se realizó un ensayo preliminar de secado por atomización de la suspensión de G1, compuesta por: 10 g de G1, 1 g de Aerosil (Aerosil®, Degusa, Bélgica, 1 g de laurilsulfato de sodio y 100 mL de agua. La atomización se efectuó en un equipo de laboratorio (Buchi Mini Dryer spray a 90 ºC. La dispersión sólida obtenida fue caracterizada físico-químicamente mediante difracción de rayos X, granulometría láser por el método de difracción angular, calorimetría diferencial de barrido, microscopia electrónica de barrido y espectrofotometría de absorción infraroja. Resultados: las partículas obtenidas presentaron un pequeño tamaño, forma esférica y un incremento de la cristalinidad del G-1; no se encontraron interacciones entre los componentes de la dispersión ni presencia de productos de degradación, y la solubilidad del G-1 en agua resultó notablemente incrementada. Conclusiones: el producto obtenido por la técnica de secado por atomización incrementó apreciablemente la solubilidad del G1 sin afectar los grupos funcionales, responsables de la actividad terapéutica que se le reportan al ingrediente activo estudiado. Estos alentadores resultados sugieren la necesidad de continuar estudios para la optimización del proceso y realizar al producto obtenido ensayos de estabilidad con el objetivo de su futura inclusión en formas farmacéuticas de dosificación.Objective: to increase the solubility of 2-bromium-5(2-bromium-2-nitrovinyl-furane (G1, one pharmaceutically active ingredient with potent bactericidal and fungicidal action

Nanocrystal/sol-gel nanocomposites

Science.gov (United States)

Petruska, Melissa A [Los Alamos, NM; Klimov, Victor L [Los Alamos, NM

2007-06-05

The present invention is directed to solid composites including colloidal nanocrystals within a sol-gel host or matrix and to processes of forming such solid composites. The present invention is further directed to alcohol soluble colloidal nanocrystals useful in formation of sol-gel based solid composites.

Influencia de un sólido sobre el secado de mezclas líquidas parcialmente miscibles

Directory of Open Access Journals (Sweden)

M. Vargas

2006-01-01

Full Text Available Un estudio experimental del secado convectivo de un sólido humedecido con una mezcla líquida que exhibe separación de fases durante el proceso de evaporación ha sido efectuado. Los experimentos fueron realizados en un secador de túnel a escala de laboratorio bajo diferentes condiciones de operación tales como temperatura y velocidad del gas así como diferentes composiciones de las mezclas líquidas. Se humedeció el sólido con mezclas binarias y ternarias, y se efectuó la evaporación a partir de la superficie libre líquida. Se utilizo como humedad el sistema binario agua-hexano y la mezcla ternaria agua-hexano-etanol, ambos involucrados en la extracción de biopesticida a partir de semillas de nim. Esferas de vidrio y semillas de nim trituradas fueron usadas como sólido. La densidad y el índice de distribución másico de las fases tienen gran influencia en el proceso de evaporación. Si la fase menos densa del hexano esta en exceso, la superficie es cubierta solamente por esta fase y no existe evaporación de la otra fase hasta que el índice de distribución másico es tal que la segunda fase es expuesta al gas. La presencia de un sólido poroso interrumpe este patrón y la fase más densa puede ser removida simultáneamente incluso a bajas fracciones de esta última. En este caso, también la forma en que el sólido fue humedecido tiene influencia en el proceso.

Effect of sol-age on the surface and optical properties of sol-gel derived mesoporous zirconia thin films

Directory of Open Access Journals (Sweden)

Manish Kumar

2011-06-01

Full Text Available Mesoporous ZrO2 thin films have been deposited by a modified sol-gel dip coating technique using HCl as catalyst. Effects of sol-age on the surface and on the optical properties are studied. Transmission electron micrographs of the films reveal the pore dimensions in mesoporous regime. A strong correlation in surface topography with sol-age has been observed where increase in sol-age induces a systematic enhancement in the value of root mean square roughness of the films. Optical study shows that deposited films have high transmittance and an enhancement of 5.6 times in porosity in films prepared with sol-age of 10 days with respect to that of 1 day. Band gap estimation by Tauc's plots of films is observed to 5.74 eV, which shows invariance with the sol-age.

Sol-gel synthesis of hydroxyapatite; Sintese de hidroxiapatita via sol-gel

Energy Technology Data Exchange (ETDEWEB)

Zupanski, M.D.; Lucena, M.P.P.; Bergmann, C.P., E-mail: michelledunin@yahoo.com.b [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil)

2010-07-01

Hydroxyapatite (HAp) has been established as the calcium phosphate based compound with most applications in the biological field. Among the numerous techniques for synthesis of HAp, the sol-gel processing route affords great control over purity and formed phases using low processing temperatures. In addition, the sol-gel approach offers an option for homogeneous HAp coating on metal substrates, as well as the ability to generate nanocrystalline powders. In this work, the sol-gel synthesis of HAp was investigated employing triethyl phosphate and calcium nitrate tetrahydrate as phosphorous and calcium precursors, respectively. The aging effect on phase composition and powder morphology of the final product was studied in terms of temperature and aging time. The powders were studied by using X-ray diffraction, Fourier transform infrared spectroscopy, particle size distribution by laser diffraction and scanning electron microscopy. (author)

Influencia de la adición de un 2% de carbonato de calcio en el proceso de fabricación de los ladrillos de cerámica roja: etapas de secado y cocción

Directory of Open Access Journals (Sweden)

Dania Betancourt

2013-08-01

Full Text Available El trabajo hace un estudio de la influencia de la adición del 2% de carbonato de calcio en la duración de la etapa de secado y la eficiencia de la etapa de cocción durante el proceso de fabricación de ladrillos de cerámica roja. Dicho estudio se realizó en una fábrica que produce ladrillos huecos con una capacidad instalada de 65000 ladrillos por cada quema .Los resultados del estudio realizado demostraron que la adición de un 2% de CaCO3 a la pasta arcillosa disminuye el tiempo de secado en un 35% con respecto a los ladrillos elaborados sin adición y provoca una disminución del consumo de combustible del 27 % con respecto a quemas anteriores realizadas sin la adición de este fundente debido a la reducción del tiempo de cocción en los hornos.

Preparation, microstructure and properties of yttrium aluminum garnet fibers prepared by sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Li Chengshun [Key Laboratory for Liquid Structure and Heredity of Materials of Ministry of Education, Shandong University, Jinan 250061 (China); Zhang Yujun [Key Laboratory for Liquid Structure and Heredity of Materials of Ministry of Education, Shandong University, Jinan 250061 (China)], E-mail: yujunzhangcn@sdu.edu.cn; Gong Hongyu; Zhang Jingde; Nie Lifang [Key Laboratory for Liquid Structure and Heredity of Materials of Ministry of Education, Shandong University, Jinan 250061 (China)

2009-01-15

Yttrium aluminum garnet (YAG) fiber was prepared by sol-gel method using water as the solvent. The spinnable YAG sol was synthesized using Al powder, Y(CH{sub 3}COOH){sub 3}.4H{sub 2}O and HCl as precursors, polyethylene oxide as viscosity adjusting agent. Gel fibers with diameter of 5-10 {mu}m were prepared from the YAG sol by using centrifugal spinning technique. YAG crystalline fibers were obtained by drying gel fibers and heat-treating at selected temperature. TG/DTA analysis showed an exotherm at 906 deg. C attributed to formation of YAG phase and weight loss of 45% at 1000 deg. C. XRD and FT-IR analysis showed that phase-pure YAG can be formed at 900 deg. C, and no other intermediate was observed. The grain size of YAG fibers increased from 25 to 220 nm and tensile strength decreased rapidly from 970 to 380 MPa when the sintering temperature increased from 900 to 1550 deg. C.

Low Concentration Fe-Doped Alumina Catalysts Using Sol-Gel and Impregnation Methods: The Synthesis, Characterization and Catalytic Performance during the Combustion of Trichloroethylene

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Carolina Solis Maldonado

2014-03-01

Full Text Available The role of iron in two modes of integration into alumina catalysts was studied at 0.39 wt% Fe and tested in trichloroethylene combustion. One modified alumina was synthesized using the sol-gel method with Fe added in situ during hydrolysis; another modification was performed using calcined alumina, prepared using the sol-gel method and impregnated with Fe. Several characterization techniques were used to study the level of Fe modification in the γ-Al2O3 phase formed and to correlate the catalytic properties during trichloroethylene (TCE combustion. The introduction of Fe in situ during the sol-gel process influenced the crystallite size, and three iron species were generated, namely, magnetite, maghemite and hematite. The impregnated Fe-alumina formed hematite and maghemite, which were highly dispersed on the γ-Al2O3 surface. The X-ray photoelectron spectra (XPS, FT-IR and Mössbauer spectroscopy analyses revealed how Fe interacted with the γ-Al2O3 lattice in both catalysts. The impregnated Fe-catalyst showed the best catalytic performance compared to the catalyst that was Fe-doped in situ by the sol-gel method; both had better catalytic activity than pure alumina. This difference in activity was correlated with the accessibility of the reactants to the hematite iron species on the surface. The chlorine poisoning for all three catalysts was less than 1.8%.

Dielectric Properties of Sol-Gel Derived Barium Strontium Titanate and Microwave Sintering of Ceramics

Science.gov (United States)

Selmi, Fathi A.

This thesis consists of two areas of research: (1) sol-gel processing of Ba_{rm 1-x}Sr_{rm x} TiO_3 ceramics and their dielectric properties measurement; and (2) microwave versus conventional sintering of ceramics such as Al_2 O_3, Ba_{ rm 1-x}Sr_{rm x}TiO_3, Sb-doped SnO _2 and YBa_2Cu _3O_7. Sol-gel powders of BaTiO_3, SrTiO_3, and their solid solutions were synthesized by the hydrolysis of titanium isopropoxide and Ba and Sr methoxyethoxides. The loss tangent and dielectric constant of both sol-gel and conventionally prepared and sintered Ba_{rm 1-x}Sr _{rm x}TiO _3 ceramics were investigated at high frequencies. The sol-gel prepared ceramics showed higher dielectric constant and lower loss compared to those prepared conventionally. Ba _{rm 1-x}Sr _{rm x}TiO_3 ceramics were tunable with applied bias, indicating the potential use of this material for phase shifter applications. Porous Ba_{0.65}Sr _{0.35}TiO_3 was also investigated to lower the dielectric constant. Microwave sintering of alpha -Al_2O_3 and SrTiO_3 was investigated using an ordinary kitchen microwave oven (2.45 GHz; 600 Watts). The use of microwaves with good insulation of alpha -Al_2O_3 and SrTiO_3 samples resulted in their rapid sintering with good final densities of 96 and 98% of the theoretical density, respectively. A comparison of grain size for conventionally and microwave sintered SrTiO_3 samples did not show a noticeable difference. However, the grain size of microwave sintered alpha-Al_2O _3 was found to be larger than that of conventionally sintered sample. These results show that rapid sintering of ceramics can be achieved by using microwave radiation. The sintering behavior of coprecipitated Sb-doped SnO_2 was investigated using microwave power absorption. With microwave power, samples were sintered at 1450^circC for 20 minutes and showed a density as high as 99.9% of theoretical. However, samples fired in a conventional electric furnace at the same temperature for 4 hours showed only

Sol-gel bonding of silicon wafers

International Nuclear Information System (INIS)

Barbe, C.J.; Cassidy, D.J.; Triani, G.; Latella, B.A.; Mitchell, D.R.G.; Finnie, K.S.; Short, K.; Bartlett, J.R.; Woolfrey, J.L.; Collins, G.A.

2005-01-01

Sol-gel bonds have been produced between smooth, clean silicon substrates by spin-coating solutions containing partially hydrolysed silicon alkoxides. The two coated substrates were assembled and the resulting sandwich fired at temperatures ranging from 60 to 600 deg. C. The sol-gel coatings were characterised using attenuated total reflectance Fourier transform infrared spectroscopy, ellipsometry, and atomic force microscopy, while the corresponding bonded specimens were investigated using scanning electron microscopy and cross-sectional transmission electron microscopy. Mechanical properties were characterised using both microindentation and tensile testing. Bonding of silicon wafers has been successfully achieved at temperatures as low as 60 deg. C. At 300 deg. C, the interfacial fracture energy was 1.55 J/m 2 . At 600 deg. C, sol-gel bonding provided superior interfacial fracture energy over classical hydrophilic bonding (3.4 J/m 2 vs. 1.5 J/m 2 ). The increase in the interfacial fracture energy is related to the increase in film density due to the sintering of the sol-gel interface with increasing temperature. The superior interfacial fracture energy obtained by sol-gel bonding at low temperature is due to the formation of an interfacial layer, which chemically bonds the two sol-gel coatings on each wafer. Application of a tensile stress on the resulting bond leads to fracture of the samples at the silicon/sol-gel interface

Sol-gel processing to form doped sol-gel monoliths inside hollow core optical fiber and sol-gel core fiber devices made thereby

Science.gov (United States)

Shaw, Harry C. (Inventor); Ott, Melanie N. (Inventor); Manuel, Michele V. (Inventor)

2002-01-01

A process of fabricating a fiber device includes providing a hollow core fiber, and forming a sol-gel material inside the hollow core fiber. The hollow core fiber is preferably an optical fiber, and the sol-gel material is doped with a dopant. Devices made in this manner includes a wide variety of sensors.

Kinetic Study of Convective Drying of Blueberry Variety O’neil (Vaccinium corymbosum L. Estudio de la Cinética del Secado Convectivo de Arándano Variedad O’Neil (Vaccinium corymbosum L.

Directory of Open Access Journals (Sweden)

A Vega-Gálvez

2009-06-01

Full Text Available The aim of this research was to study and to model the drying kinetics of the blueberry Vaccinium corymbosum L. at three temperatures (60, 70 and 80 ºC with an airflow of 2.0 ± 0.2 m s-1. Modeling of the desorption isotherm was carried out with the GAB (Guggenheim, Anderson and de Boer equation, showing a good fit to experimental moisture data, giving as a result a monolayer moisture level of 0.084 g water g-1 dm. Newton, Henderson-Pabis, Page, Modified Page and Logarithmic mathematical models were applied in the study and in the modeling of the drying kinetics of this fruit. Kinetic parameters k of each model showed dependence on temperature, and were evaluated by an Arrhenius-type equation, with an activation energy of between 36.2 and 54.5 kJ mol-1. Logarithmic and Modified Page models gave the best fits for each drying curve, based on the statistical test determination coefficient, sum square error, root mean sum errors and Chi-square. In consequence, both models are excellent tools for estimating the drying time of this product.El objetivo de esta investigación fue estudiar y modelar la cinética de secado del arándano ( Vaccinium corymbosum L. a tres temperaturas (60, 70 y 80 ºC con un flujo de aire de 2,0 ± 0,2 m s-1. El modelado de la isoterma de desorción se llevó a cabo con la ecuación de GAB (Guggenheim, Anderson y de Boer, mostrando un buen ajuste sobre los datos experimentales de humedad, dando como resultado una humedad de la monocapa de 0,084 g de agua g-1 ms. Se aplicaron los modelos matemáticos de Newton, Henderson-Pabis, Page, Page modificado y Logarítmico para el modelado de la cinética de secado de esta fruta. Los parámetros cinéticos k de cada modelo presentaron dependencia con la temperatura, evaluadas por una ecuación de tipo Arrhenius, con una energía de activación entre 36,2-54,5 kJ mol-1. Los modelos Logarítmico y Page modificado obtuvieron el mejor ajuste para cada curva de secado, basado en las

Optimal hysteretic control for a B M A P &sol; S M &sol; 1 &sol; N queue with two operation modes

Directory of Open Access Journals (Sweden)

Dudin Alexander N.

1999-01-01

Full Text Available We consider B M A P &sol; S M &sol; 1 type queueing system with finite buffer of size N . The system has two operation modes, which are characterized by the matrix generating function of B M A P -input, the kernel of the semi-Markovian service process, and utilization cost. An algorithm for determining the optimal hysteresis strategy is presented.

ESTUDIO DE LA CINÉTICA FISICOQUÍMICA DEL MANGO (Mangifera indica L. Var. Tommy Atkins) TRATADO POR MÉTODOS COMBINADOS DE SECADO

OpenAIRE

MORENO, ANGÉLICA; LEÓN, DAVID; GIRALDO, GERMAN; RIOS, EUNICE

2010-01-01

El seguimiento cinético de los parámetros de peso, actividad de agua (a w) y ganancia de sólidos solubles (ºBrix) en cubos de mango (Mangifera indica L. Var. Tommy Atkins) fueron evaluados durante los procesos de deshidratación osmótica con o sin pulso de vacío (DO y DOPV) en combinación con el secado por aire caliente (SAC) o a vacío (VAC). Se observó que la DOPV y el SAC son los métodos más efectivos ya que requieren menor tiempo de proceso para alcanzar sus niveles adecuados de humedad par...

Sol-gel-state of hydrated zirconium dioxide

International Nuclear Information System (INIS)

Karakchiev, L.G.; Lyakhov, N.Z.

1995-01-01

The change in viscosity and density of a system in the course of sol-gel-xerogel has been traced. The size and molecular mass of particles in sol have been determined. Initial sol is practically a monodisperse system. Gel is a spatial net of similar particles. Reversible character of sol-gel transition with a change in water content in the system suggests instability of the bond between the particles in the structure of the solid state body formed. 11 refs.; 4 figs

Evaluation of sol-gel derived Eu2+ activated SrMgAl2SiO7 as a novel nanostructure luminescent pigment

International Nuclear Information System (INIS)

Sameie, H.; Salimi, R.; Sabbagh Alvani, A.A.; Sarabi, A.A.; Moztarzadeh, F.; Tahriri, M.

2010-01-01

A novel nanostructure pigment of Eu 2+ doped SrMgAl 2 SiO 7 was prepared via the sol-gel route. The phase composition and condition of crystallites during heating were characterized by X-ray diffraction (XRD) analysis. Investigation of optical properties by spectrophotometer illustrated that under short ultraviolet excitation wavelength, the main emission peak occurred at about 415-420 nm. Also, relatively pure purplish blue color was observed that can be ascribed to the 4f 6 5d 1 ( 2 D)→4f 7 ( 8 S 7/2 ) transition of Eu 2+ . The effect of calcination temperature on the luminescence properties of the phosphors was evaluated and, also in this case, scanning electron microscope (SEM) was employed. From colorimetry results, color coordinations of phosphor shift towards the deep blue region as calcination temperature increases. Finally, grain size of products at optimum calcination temperature was estimated to be about 20-30 nm using Scherrer's equation, which was consistent with transmission electron microscopy (TEM) observations.

Method of making ionic liquid mediated sol-gel sorbents

Science.gov (United States)

Malik, Abdul; Shearrow, Anne M.

2017-01-31

Ionic liquid (IL)-mediated sol-gel hybrid organic-inorganic materials present enormous potential for effective use in analytical microextraction. One obstacle to materializing this prospect arises from high viscosity of ILs significantly slowing down sol-gel reactions. A method was developed which provides phosphonium-based, pyridinium-based, and imidazolium-based IL-mediated advanced sol-gel organic-inorganic hybrid materials for capillary microextraction. Scanning electron microscopy results demonstrate that ILs can serve as porogenic agents in sol-gel reactions. IL-mediated sol-gel coatings prepared with silanol-terminated polymers provided up to 28 times higher extractions compared to analogous sol-gel coatings prepared without any IL in the sol solution. This study shows that IL-generated porous morphology alone is not enough to provide effective extraction media: careful choice of the organic polymer and the precursor with close sol-gel reactivity must be made to ensure effective chemical bonding of the organic polymer to the created sol-gel material to be able to provide the desired sorbent characteristics.

Sol-gel additive for systems with inorganic binders

International Nuclear Information System (INIS)

Akstinat, M.; Antenen, D.; Suter, W.

1996-01-01

A sol-gel additive for inorganic binder systems and sol-gel process for producing air-placed concrete and mortar by using such sol-gel additives are disclosed. Sol-gel additives for gel-derived inorganic binder systems (for example plaster, cement, lime, special slags, etc.) marked improve the consistency of such binder systems during processing or allow their consistency to be regulated. In addition, these sol-gel additives regulate setting times and substantially improve durability (chemical resistance, reduced permeability) and the mechanical properties of the set binder system. (author)

ESTUDIO DE LAS PROPIEDADES FÍSICAS Y DE LA CINÉTICA DE SECADO DE GRANOS DE MAIZ COLORADO DURO

OpenAIRE

Matías R. Ordóñez; María C. Gely; Ana M. Pagano

2012-01-01

Se estudió el efecto de la humedad sobre propiedades físicas de granos de maíz Colorado Duro en el rango 17− 35% base seca, y la cinética de secado a temperaturas entre 30− 90°C y a velocidad de 0.43 m/s. El 12.91x10-3 m), diámetro contenido de humedad tuvo efecto significativo sobre la longitud (12.059x10-3− -3 -3 -3 -3 geométrico (7.8x10 − 8.281x10 m), diámetro equivalente (8.18x10 − 8.63x10 m), peso de mil granos (363.6− 421.9 g), ángulo de reposo (10.11− 24.66°), y densidades aparente (0....

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)

Effect of Chelating Agents on the Stability of Nano-TiO2 Sol Particles for Sol-Gel Coating.

Science.gov (United States)

Maeng, Wan Young; Yoo, Mi

2015-11-01

Agglomeration of sol particles in a titanium alkoxide (tetrabutyl orthotitanate (TBOT), > 97%) solution during the hydrolysis and condensation steps makes the sol solution difficult to use for synthesizing homogeneous sol-gel coating. Here, we have investigated the effect of stabilizing agents (acetic acid and ethyl acetoacetate (EAcAc)) on the agglomeration of Ti alkoxide particles during hydrolysis and condensation in order to determine the optimized conditions for controlling the precipitation of TiO2 particles. The study was conducted at R(AC) ([acetic acid]/[TBOT]) = 0.1-5 and R(EAcAc)([EAcAc]/[TBOT]) = 0.05-0.65. We also studied the effects of a basic catalyst ethanolamine (ETA), water, and HCl on sol stability. The chelating ligands in the precursor sol were analyzed with FT-IR. The coating properties were examined by focused ion beam. The stabilizing agents (acetic acid and EAcAc) significantly influenced the agglomeration and precipitation of TBOT precursor particles during hydrolysis. As R(AC) and R(EAcAc) increased, the agglomeration remarkably decreased. The stability of the sol with acetic acid and EAcAc arises from the coordination of the chelating ligand to TBOT that hinders hydrolysis and condensation. A uniform fine coating (thickness: 30 nm) on stainless steel was obtained by using an optimized sol with R(AC) = 0.5 and R(EAcAc) = 0.65.

Structural evolution of silica sols modified with formamide

Directory of Open Access Journals (Sweden)

Lenza R.F.S.

2001-01-01

Full Text Available In this work we investigated the influence of formamide on the acid-catalyzed sol-gel process by Fourier transform infrared spectroscopy (FTIR. Three silica sols were studied: Sol catalyzed with nitric acid without formamide, sol catalyzed with nitric acid containing formamide and sol catalyzed with a mixture of nitric acid and hydrofluoric acid and modified with formamide. Following the time evolution of both the Si-(OH stretching vibration at around 950 cm-1 and the Si-O-(Si vibration between 1040 cm-1 and 1200 cm-1 we were able to describe the structural evolution of each sol. The curve of evolution of Si-(OH stretching vibration corresponding to sol A has a simple asymptotic evolution. In the case of formamide containing sol, we observed a two-step structural evolution indicating that for the system containing formamide the polymerization goes through a temporary stabilization of oligomers, which can explain the non-variation of the Si-O(H bond wavenumber for a certain time. Gelation times were of several days for gels without formamide and few hours for gels containing additive. The presence of additive resulted in a highly interconnected gel.

Characterization of the calcium-fluoroaluminosilicate glass prepared by a non-hydrolytic sol-gel route for future dental application as glass ionomer cement

Directory of Open Access Journals (Sweden)

Alexandre Cestari

2009-06-01

Full Text Available Glass ionomer cements are widely employed in dentistry due to their physical, biological and mainly anti-caries properties. Glass ionomers consist of an aluminosilicate glass matrix modified with other elements, and they contain large quantities of fluorine. In this study, we report on the preparation of calcium-fluoroaluminosilicate glasses by a nonhydrolytic sol-gel route as an alternative approach to obtaining alumina-silica matrices. The glass powders were prepared via the non-hydrolytic sol-gel method, by mixing AlCl3, SiCl4, CaF2, AlF3, NaF, and AlPO4. The powders were studied by thermal analysis (TG/DTA/DSC, photoluminescence (PL, nuclear magnetic resonance (NMR27Al-29Si, and X ray diffraction (XRD. TG/DTA/DSC analyses revealed a constant mass loss due to structural changes during the heating process, which was confirmed by NMR and PL. A stable aluminosilicate matrix with potential future application as a glass ionomer base was obtained.

Functional coatings: the sol-gel approach

International Nuclear Information System (INIS)

Belleville, Ph.

2010-01-01

CEA's sol-gel laboratory is specialized in the development of innovative sol-gel optical coatings and has extended its application field to membrane materials and coatings for energy conversion, to electric coatings for microelectronics devices and to thin films for gas sensing. This article describes, by way of examples, the laboratory's research on sol-gel functional coatings, including nano-material synthesis, organic-inorganic hybrid-based solution preparation as well as deposition process development and prototyping. (author)

The SOL width and the MHD interchange instability in tokamaks

Energy Technology Data Exchange (ETDEWEB)

Kerner, W [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Pogutse, O [Kurchatov institute, Moscow (Russian Federation)

1994-07-01

Instabilities in the SOL plasma can strongly influence the SOL plasma behaviour and in particular the SOL width. The SOL stability analysis shows that there exists a critical ratio of the thermal energy and the magnetic energy. If the SOL beta is greater than this critical value, the magnetic field cannot prevent the plasma displacement and a strong MHD instability in the SOL occurs. In the opposite case only slower resistive instabilities can develop. A theoretical investigation of the SOL plasma stability is presented for JET single-null and double-null divertor configurations. The dependence of the stability threshold on the SOL beta and on the sheath resistance is established. Applying a simple mixing length argument gives the scaling of the SOL width. 5 refs., 2 figs.

Sol-gel method for encapsulating molecules

Science.gov (United States)

Brinker, C. Jeffrey; Ashley, Carol S.; Bhatia, Rimple; Singh, Anup K.

2002-01-01

A method for encapsulating organic molecules, and in particular, biomolecules using sol-gel chemistry. A silica sol is prepared from an aqueous alkali metal silicate solution, such as a mixture of silicon dioxide and sodium or potassium oxide in water. The pH is adjusted to a suitably low value to stabilize the sol by minimizing the rate of siloxane condensation, thereby allowing storage stability of the sol prior to gelation. The organic molecules, generally in solution, is then added with the organic molecules being encapsulated in the sol matrix. After aging, either a thin film can be prepared or a gel can be formed with the encapsulated molecules. Depending upon the acid used, pH, and other processing conditions, the gelation time can be from one minute up to several days. In the method of the present invention, no alcohols are generated as by-products during the sol-gel and encapsulation steps. The organic molecules can be added at any desired pH value, where the pH value is generally chosen to achieve the desired reactivity of the organic molecules. The method of the present invention thereby presents a sufficiently mild encapsulation method to retain a significant portion of the activity of the biomolecules, compared with the activity of the biomolecules in free solution.

Sol-gel derived sorbents

Science.gov (United States)

Sigman, Michael E.; Dindal, Amy B.

2003-11-11

Described is a method for producing copolymerized sol-gel derived sorbent particles for the production of copolymerized sol-gel derived sorbent material. The method for producing copolymerized sol-gel derived sorbent particles comprises adding a basic solution to an aqueous metal alkoxide mixture for a pH.ltoreq.8 to hydrolyze the metal alkoxides. Then, allowing the mixture to react at room temperature for a precalculated period of time for the mixture to undergo an increased in viscosity to obtain a desired pore size and surface area. The copolymerized mixture is then added to an immiscible, nonpolar solvent that has been heated to a sufficient temperature wherein the copolymerized mixture forms a solid upon the addition. The solid is recovered from the mixture, and is ready for use in an active sampling trap or activated for use in a passive sampling trap.

The influence of p H and UV visible absorption on hydrolysis stage and gel behavior of glasses synthesized by sol-gel

International Nuclear Information System (INIS)

Khosravi Saghezchi, M.; Sarpoolaky, H.; Heshmatpour, F.

2008-01-01

Lead-containing glass borosilicate was synthesized by Sol-gel technique using metal alkoxide such as tetra ethyleorthosilicate, Al-sec-butoxide and trimethyl borate. The sol containing tetra ethyle ortho silicate converts to gel during drop wise addition of Al-alkoxide while inorganic lead salt was added in the last stage of gelation to prepare the alcogels. The specimens were dried at room temperature to set then heated at 600 d eg C quickly to avoid crystallization preparing a glass containing 63 weight percent lead oxide. The influence of p H on absorption behavior of the sols studied by UV visible technique so the characteristic of the gel, alcogel and xerogel were studied in the different acidic concentrations. The UV spectrums show that the higher the acidity of the hydrolysis stages, the higher the absorbance. The results showed the sample with 63 weight percent lead was found fully amorphous. Microstructure and phase analysis of the glass powders were investigated by X-ray diffraction, X-ray fluorescence and scanning electron microscopy equipped with energy dispersive spectroscopy analysis

Fluorescence yield in rare-earth-doped sol-gel silicate glasses

Energy Technology Data Exchange (ETDEWEB)

Silversmith, A.J., E-mail: asilvers@hamilton.ed [Physics Department, Hamilton College, 198 College Hill Road, Clinton, NY 13323 (United States); Nguyen, Nguyen T.T.; Campbell, D.L. [Physics Department, Hamilton College, 198 College Hill Road, Clinton, NY 13323 (United States); Boye, D.M.; Ortiz, C.P. [Davidson College, Davidson, NC 28035 (United States); Hoffman, K.R. [Whitman College, Walla Walla, WA 99362 (United States)

2009-12-15

We have used trivalent terbium to investigate the mechanism behind fluorescence enhancement by Al{sup 3+} co-doping. Our results indicate that rare-earth (RE) ions cluster together in aluminum-rich regions of the glass, and behave as if they were dispersed uniformly throughout these regions when the ratio of Al to RE is {approx}10 or greater. We also studied the effects of adding chemical drying agents to the precursor solution for the synthesis of sol-gel-derived silicate glasses. Such glasses can be treated at significantly higher annealing temperatures without degradation of optical quality, and have the density of melt glass. Fluorescence yield from doped RE ions improves markedly with the addition of the drying agents, and the denser glasses are not subject to rehydration.

Synthesis of uranium and thorium dioxides by Complex Sol-Gel Processes (CSGP). Synthesis of uranium oxides by Complex Sol-Gel Processes (CSGP)

International Nuclear Information System (INIS)

Deptula, A.; Brykala, M.; Lada, W.; Olczak, T.; Wawszczak, D.; Chmielewski, A.G.; Modolo, G.; Daniels, H.

2010-01-01

In the Institute of Nuclear Chemistry and Technology (INCT), a new method of synthesis of uranium and thorium dioxides by original variant of sol-gel method - Complex Sol-Gel Process (CSGP), has been elaborated. The main modification step is the formation of nitrate-ascorbate sols from components alkalized by aqueous ammonia. Those sols were gelled into: - irregularly agglomerates by evaporation of water; - medium sized microspheres (diameter <150) by IChTJ variant of sol-gel processes by water extraction from drops of emulsion sols in 2-ethylhexanol-1 by this solvent. Uranium dioxide was obtained by a reduction of gels with hydrogen at temperatures >700 deg. C, while thorium dioxide by a simple calcination in the air atmosphere. (authors)

Mesure de la vitesse d'infiltration des eaux dans le sol : Cas des sols ...

African Journals Online (AJOL)

C'est donc une infiltration superficielle qui ne peut pas modifier la composition des eaux de l'aquifère. Ces sols sont alors favorables à une telle agriculture. Mots clés: mesure, vitesse, infiltration, sols, pollutions, eau, Niari, Congo. English Title: Measuring the speed of the water infiltration into the soil: case of the soil of the ...

Effect of alumina sol addition to micro-arc oxidation electrolyte on the properties of MAO coatings formed on magnesium alloy AZ91D

International Nuclear Information System (INIS)

Laleh, M.; Rouhaghdam, A. Sabour; Shahrabi, T.; Shanghi, A.

2010-01-01

Oxide coatings were formed on AZ91D magnesium alloy using micro-arc oxidation process in alkaline electrolyte without and with addition of alumina sol. The microstructures and compositions of the MAO coatings were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). Corrosion behaviors of the coatings were evaluated with electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in 3.5%NaCl solution. Porosities of the coatings were measured by potentiodynamic polarization tests. It was found that the coating produced in the electrolyte with alumina sol has more compact and uniform morphology than that produced in the electrolyte without alumina sol. The results of corrosion tests showed that the coating formed in electrolyte with alumina sol enhances the corrosion resistance of the substrate significantly. XRD patterns showed that the coating produced in the electrolyte with alumina sol has more MgAl 2 O 4 phase than MgO.

Opportunity's Surroundings on Sol 1687

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on the 1,687th Martian day, or sol, of its surface mission (Oct. 22, 2008). Opportunity had driven 133 meters (436 feet) that sol, crossing sand ripples up to about 10 centimeters (4 inches) tall. The tracks visible in the foreground are in the east-northeast direction. Opportunity's position on Sol 1687 was about 300 meters southwest of Victoria Crater. The rover was beginning a long trek toward a much larger crater, Endeavour, about 12 kilometers (7 miles) to the southeast. This view is presented as a cylindrical projection with geometric seam correction.

Effect of microwave and air drying of parboiled rice on stabilization of rice bran oil

Directory of Open Access Journals (Sweden)

Rizk, Laila F.

1995-06-01

Full Text Available Two rice varieties, Giza 175 (short grain and Giza 181 (long grain were partDoiled by soaking the grains at room temperature for 20 hours and steaming for 15 min then dried either at room temperature or by microwave. The results indicated that air and microwave drying significantly increased oil extraction in both rice bran varieties. Parboiling followed by air or microwave drying produced a slight change on protein, fiber and ash content of rice bran and reduced the development of free fatty acids (F.F.A. In oil bran. Microwave samples have less F.F.A. content than the corresponding samples air dried. Oils from the cold stored rice bran presented lower F.F.A. than the corresponding oil bran stored at room temperature. The ratio between total unsaturated fatty acids and total saturated ones (Tu/Ts decreased after air and microwave drying. Results also show that air drying increased the ratio of total hydrocarbons and total sterols (Tu/Ts in both varieties while microwave decreased it.

Dos variedades de arroz, Giza 175 (grano corto y Giza 181 (grano largo se precocieron mediante la puesta en remojo de los granos a temperatura ambiente durante 20 horas y cocimiento al vapor durante 15 minutos, luego se secaron a temperatura ambiente o por microondas. Los resultados indicaron que el secado al aire y en microondas aumentó significativamente la extracción del aceite en ambas variedades de salvado de arroz. El precocido seguido del secado al aire o en microondas produjo un cambio pequeño en el contenido en proteína, fibra y ceniza y redujo el desarrollo de ácidos grasos libres (F.F.A. en el aceite de salvado. Las muestras secadas en microondas tuvieron un menor contenido en F.F.A. que las muestras correspondientes al secado en aire. Aceites de salvado de arroz almacenado en frió presentaron menor F.F.A. que los almacenados a temperatura ambiente. La relación entre ácidos grasos insaturados totales y los saturados totales (Tu/Ts disminuy

Effects of parameters of sol-gel process on the phase evolution of sol-gel-derived hydroxyapatite

International Nuclear Information System (INIS)

Eshtiagh-Hosseini, Hossein; Housaindokht, Mohammad Reza; Chahkandi, Mohammad

2007-01-01

It has been established that hydroxyapatite powders can be produced using an alkoxide-based sol-gel technique. Nanocrystalline powders of hydroxyapatite (HA) were prepared from Ca(NO 3 ) 2 .4H 2 O and PO(OC 2 H 5 ) 3 as calcium and phosphorus precursors, respectively, using a sol-gel route. For a number of samples, sol of phosphorus was first hydrolyzed for 24 h with distilled water. The sol temperature, aging time and heat treatment temperature on apatite formation were systematically studied. Increasing the aging time affected the reducing of CaO. Also, increasing the mixed sol solution temperature up to 80 deg. C had a positive effect on the disappearance of impurity phases. With the increase of the calcination temperature >600 deg. C, calcium phosphate impurity phases disappeared. Structural evolution during the synthesis of hydroxyapatite is investigated by using infrared (IR) analysis, X-ray diffraction (XRD), thermal behavior (DTA), and elemental analysis of electron microscopy examination (SEM). X-ray diffraction with the aid of Scherrer and Williamson-Hall equations has been used to characterize the distributions of crystallite size and micro-strain of HA powders .The results indicated that mean crystallite size increased and micro-strain decreased significantly with the rise in firing temperature

PELÍCULAS DELGADAS DE ZnO IMPURIFICADAS CON ALUMINIO Y FLÚOR PREPARADAS POR SOL-GEL

Directory of Open Access Journals (Sweden)

Salvador Tirado

2012-01-01

Full Text Available Se han fabricado películas delgadas de óxido de cinc impurificadas con aluminio y flúor (ZnO:Al:F, mediante el proceso de sol-gel y la técnica de inmersión repetida. Las películas se depositaron sobre sustratos de vidrio sodo-cálcico. Se ha estudiado el efecto del envejecimiento del sol y el espesor de las películas sobre estructura, morfología, propiedades ópticas y eléctricas. Películas policristalinas ZnO:Al:F resultaron con orientación preferencial del plano (002. Resultó un tamaño de cristal para las películas en el rango de 18-39 nm. En las mejores películas se registraron valores de 5x10-1 y 12x10-1 Ω cm para la resistividad. Las películas presentaron una transmitancia de 75 a 85%. De los espectros UV se evaluó un ancho de banda de 3.31 a 3.34 eV para las películas. Las películas ZnO:Al:F al 0.5% at., presentan propiedades físicas y químicas tales, que podrían aplicarse en celdas solares en tecnología de película delgada.

Sol-gel synthesis and characterization of hybrid inorganic-organic Tb(III)-terephthalate containing layered double hydroxides

Science.gov (United States)

Smalenskaite, A.; Salak, A. N.; Ferreira, M. G. S.; Skaudzius, R.; Kareiva, A.

2018-06-01

Mg3/Al1 and Mg3Al1-xTbx layered double hydroxides (LDHs) intercalated with terephthalate anion were synthesized using sol-gel method. The obtained materials were characterized by X-ray diffraction (XRD) analysis, infrared (FTIR) spectroscopy, fluorescence spectroscopy (FLS) and scanning electron microscopy (SEM). The Tb3+ substitution effects in the Mg3Al1-xTbx LDHs were investigated by changing the Tb3+ concentration in the cation layers. The study indicates that the organic guest-terephthalate in the interlayer spacing of the LDH host influences the luminescence of the hybrid inorganic-organic materials.

Highly concentrated zinc oxide nanocrystals sol with strong blue emission

International Nuclear Information System (INIS)

Vafaee, M.; Sasani Ghamsari, M.; Radiman, S.

2011-01-01

Highly concentrated ZnO sol was synthesized by an improved sol-gel method. Water was used as a modifier to control the sol-gel reaction and provide a way to increase the sol concentration. Concentration of ZnO in the prepared sol is higher than from other methods. Optical absorption and photoluminescence were used to investigate optical properties of the prepared sol. FTIR test was performed to study the influence of water on the compounds of as-prepared sol. The size and morphology of ZnO nanoparticles have been studied by HRTEM. The prepared colloidal ZnO nanocrystals have narrow size distribution (5-8 nm) and showed strong blue emission. The prepared sol has enough potential for optoelectronic applications. - Research highlights: → Novel sol-gel route has been employed to prepare highly concentrated ZnO colloidal nanocrystals. → Water has been used to control the sources of emission in synthesized material. → A strong blue luminescent material has been obtained.

Influence of fruit maturity and calyx drying on cape gooseberry (Physalis peruviana l., stored at 18°C Influencia de la madurez del fruto y del secado del cáliz en uchuva (Physalis peruviana l., almacenada a 18°C

Directory of Open Access Journals (Sweden)

Moreno Paola

2006-12-01

Full Text Available

Cape gooseberry fruits at the maturity stages 3 (yellow greenish or 5 (yellow orange and with calyx drying for 6 hours at 18 or 24ºC, were stored at the temperature of 18ºC and 85 % relative humidity for 20 days, to evaluate physical-chemical and physiological changes. The cape gooseberry, a climacteric fruit, presented the maximum of respiration between 6 and 8 days of storage. The 6th day of storage seems to be crucial due to the very high metabolism and the maximum contents of sugars and acids on this day. Soluble solids tended to increase and the titratable acids went to diminish. The fruit's sugar content was characterized by a major concentration of sucrose, followed by glucose and fructose. While the citric acid showed its highest level at the sixth storage day that of the tartaric acid increased constantly up to 18 days. The fruit maturity stage 3 is that which best conserved the sugars and organic acids evaluated. The maturity index influenced more than calyx drying the postharvest behavior of cape gooseberry. Calyx drying at 24ºC caused the highest climacteric peak and originated the highest loss of fresh weight in fruits harvested at maturity index 5.

Key words: Physalis peruviana; respiration; climacteric fruit; Brix degrees; organic acids; sugars.

Frutos de uchuva en estados de madurez 3 (amarillo verdoso ó 5 (amarillo naranja y con secado del cáliz durante seis horas a 18 y 24ºC, se almacenaron a temperatura ambiente (18ºC y humedad relativa del 75% durante 20 días, con el fin de evaluar cambios físico-químicos y fisiológicos. La uchuva, fruto climatérico, presentó el máximo de respiración entre los 6 y 8 días de almacenamiento. El día 6 de almacenamiento parece ser crucial debido al metabolismo muy elevado y los contenidos más altos de azúcares y ácidos. Los sólidos solubles totales tendieron a aumentar, la acidez titulable a disminuir. El contenido de azúcares se caracterizó por

The Sizing and Optimization Language, (SOL): Computer language for design problems

Science.gov (United States)

Lucas, Stephen H.; Scotti, Stephen J.

1988-01-01

The Sizing and Optimization Language, (SOL), a new high level, special purpose computer language was developed to expedite application of numerical optimization to design problems and to make the process less error prone. SOL utilizes the ADS optimization software and provides a clear, concise syntax for describing an optimization problem, the OPTIMIZE description, which closely parallels the mathematical description of the problem. SOL offers language statements which can be used to model a design mathematically, with subroutines or code logic, and with existing FORTRAN routines. In addition, SOL provides error checking and clear output of the optimization results. Because of these language features, SOL is best suited to model and optimize a design concept when the model consits of mathematical expressions written in SOL. For such cases, SOL's unique syntax and error checking can be fully utilized. SOL is presently available for DEC VAX/VMS systems. A SOL package is available which includes the SOL compiler, runtime library routines, and a SOL reference manual.

Catalisadores sol-gel de Ni-SiO2 e Ni-Al2O3 aplicados na reforma de metano com CO2 = Ni-SiO2 and Ni-Al2O3 sol-gel catalysts applied to methane reforming with CO2

Directory of Open Access Journals (Sweden)

Giane Gonçalves

2005-01-01

Full Text Available A reação de reforma do metano com CO2 apresenta-se como um processopromissor de geração de gás de síntese e hidrogênio. Neste sentido, foram preparados catalisadores de níquel-sílica e níquel-alumina pelo método sol-gel, com carga metálica nominal de 8% em massa. Os catalisadores foram caracterizados por redução à temperatura programada, análise termogravimétrica e determinação da área superficial específica. A reação de reforma do metano com CO2 foi realizada em um micro-reator contendo 500 mg de catalisador, previamente ativado em uma mistura redutora contendo hidrogênio. Osensaios de reforma a seco do metano foram realizados a 800°C, na pressão atmosférica, por um período de 12 horas, com uma razão molar de alimentação de [CO2:CH4] = 6. Os produtos da reação foram analisados por cromatografia gasosa. Dentre os catalisadoresavaliados, nas condições de reação estudadas, o catalisador de níquel suportado em sílica foi o que apresentou o melhor desempenho.The dry reforming reaction of methane comes as a promising process of syngas and hydrogen. Nickel catalysts on Al2O3 and SiO2 were synthesized by sol-gel method, with metalic load of 8% weight. The catalysts were characterized by temperature programmed reduction (TPR, termogravimetry analysis (TGA and specific surface area measurements (BET. The dry reforming reaction was performed in a micro reactor packed with 500 mg of catalyst, previously activated in atmosphere of hydrogen. The dry reforming tests were done at 800oC and atmospheric pressure by a period of 12 hours, with a molar ratio in the feeding of [CO2:CH4] = 6. The products of the reaction were analyzed by gas chromatograph. The Ni-SiO2 catalysts showed better performance.

Modified silica sol coatings for surface enhancement of leather.

Science.gov (United States)

Mahltig, Boris; Vossebein, Lutz; Ehrmann, Andrea; Cheval, Nicolas; Fahmi, Amir

2012-06-01

The presented study reports on differently modified silica sols for coating applications on leather. Silica sols are prepared by acidic hydrolysis of tetraethoxysilane and modified by silane compounds with fluorinated and non-fluorinated alkylgroups. In contrast to many earlier investigations regarding sol-gel applications on leather, no acrylic resin is used together with the silica sols when applying on leather. The modified silica particles are supposed to aggregate after application, forming thus a modified silica coating on the leather substrate. Scanning electron microscopy investigation shows that the applied silica coatings do not fill up or close the pores of the leather substrate. However, even if the pores of the leather are not sealed by this sol-gel coating, an improvement of the water repellent and oil repellent properties of the leather substrates are observed. These improved properties of leather by application of modified silica sols can provide the opportunity to develop sol-gel products for leather materials present in daily life.

Application of the docking program SOL for CSAR benchmark.

Science.gov (United States)

Sulimov, Alexey V; Kutov, Danil C; Oferkin, Igor V; Katkova, Ekaterina V; Sulimov, Vladimir B

2013-08-26

This paper is devoted to results obtained by the docking program SOL and the post-processing program DISCORE at the CSAR benchmark. SOL and DISCORE programs are described. SOL is the original docking program developed on the basis of the genetic algorithm, MMFF94 force field, rigid protein, precalculated energy grid including desolvation in the frame of simplified GB model, vdW, and electrostatic interactions and taking into account the ligand internal strain energy. An important SOL feature is the single- or multi-processor performance for up to hundreds of CPUs. DISCORE improves the binding energy scoring by the local energy optimization of the ligand docked pose and a simple linear regression on the base of available experimental data. The docking program SOL has demonstrated a good ability for correct ligand positioning in the active sites of the tested proteins in most cases of CSAR exercises. SOL and DISCORE have not demonstrated very exciting results on the protein-ligand binding free energy estimation. Nevertheless, for some target proteins, SOL and DISCORE were among the first in prediction of inhibition activity. Ways to improve SOL and DISCORE are discussed.

Sol-gel processing with inorganic metal salt precursors

Science.gov (United States)

Hu, Zhong-Cheng

2004-10-19

Methods for sol-gel processing that generally involve mixing together an inorganic metal salt, water, and a water miscible alcohol or other organic solvent, at room temperature with a macromolecular dispersant material, such as hydroxypropyl cellulose (HPC) added. The resulting homogenous solution is incubated at a desired temperature and time to result in a desired product. The methods enable production of high quality sols and gels at lower temperatures than standard methods. The methods enable production of nanosize sols from inorganic metal salts. The methods offer sol-gel processing from inorganic metal salts.

Consideraciones y recomendaciones prácticas para mejorar la calidad de la madera seca de Acacia mangium Willd

Directory of Open Access Journals (Sweden)

Carolina Tenorio Monge

2011-05-01

Full Text Available Acacia mangium, es actualmente, una de las especies más utilizadas en plantaciones comerciales en Costa Rica. Sin embargo, los usos de su madera han sido restringidos debido a que presenta algunos problemas durante el proceso de secado artificial, entre los que destaca la alta variabilidad del contenido de humedad final, la alta incidencia de defectos y la presencia de bolsas de humedad. Se han investigado las causas de esta variación y del desarrollo de estos defectos y se ha encontrado que los principales factores que influyen son: la alta variabilidad en el contenido de humedad inicial de la madera, la procedencia de la materia prima, la altura, la posición radial de la tabla al extraerla del árbol y el uso de programas de secado inadecuados para la especie. Asímismo se dan una serie de recomendaciones a considerar antes de iniciar el secado artificial con el fin de lograr una mejor calidad de madera en cuanto a la variabilidad del secado y lapresencia de defectos.

Electrophoretic deposition of sol-gel-derived ceramic coatings

International Nuclear Information System (INIS)

Zhang, Y.; Crooks, R.M.

1992-01-01

In this paper the physical, optical, and chemical characteristics of electrophoretically and dip-coated sol-gel ceramic films are compared. The results indicate that electrophoresis may allow a higher level of control over the chemistry and structure of ceramic coatings than dip-coating techniques. For example, controlled-thickness sol-gel coatings can be prepared by adjusting the deposition time or voltage. Additionally, electrophoretic coatings can be prepared in a four-component alumino-borosilicate sol display interesting optical characteristics. For example, the ellipsometrically-measured refractive indices of electrophoretic coatings are higher than the refractive indices of dip-coated films cast from identical sols, and they are also higher than any of the individual sol components. This result suggests that there are physical and/or chemical differences between films prepared by dip-coating and electrophoresis

Block Gas Sol Unit in Haderslev

DEFF Research Database (Denmark)

Vejen, Niels Kristian

2000-01-01

Investigation of a SDHW system based on a Block Gas Sol Unit from Baxi A/S installed by a consumer i Haderslev, Denmark.......Investigation of a SDHW system based on a Block Gas Sol Unit from Baxi A/S installed by a consumer i Haderslev, Denmark....

SolNet

DEFF Research Database (Denmark)

Jordan, Ulrike; Vajen, Klaus; Bales, Chris

2014-01-01

-accompanying Master courses, placements of internships, and PhD scholarship projects. A new scholarship project, “SHINE”, was launched in autumn 2013 in the frame work of the Marie Curie program of the European Union (Initial Training Network, ITN). 13 PhD-scholarships on solar district heating, solar heat......SolNet, founded in 2006, is the first coordinated International PhD education program on Solar Thermal Engineering. The SolNet network is coordinated by the Institute of Thermal Engineering at Kassel University, Germany. The network offers PhD courses on solar heating and cooling, conference...... for industrial processes, as well as sorption stores and materials started in December 2013. Additionally, the project comprises a training program with five PhD courses and several workshops on solar thermal engineering that will be open also for other PhD students working in the field. The research projects...

New Record Five-Wheel Drive, Spirit's Sol 1856

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,856th Martian day, or sol, of Spirit's surface mission (March 23, 2009). The center of the view is toward the west-southwest. The rover had driven 25.82 meters (84.7 feet) west-northwestward earlier on Sol 1856. This is the longest drive on Mars so far by a rover using only five wheels. Spirit lost the use of its right-front wheel in March 2006. Before Sol 1856, the farthest Spirit had covered in a single sol's five-wheel drive was 24.83 meters (81.5 feet), on Sol 1363 (Nov. 3, 2007). The Sol 1856 drive made progress on a route planned for taking Spirit around the western side of the low plateau called 'Home Plate.' A portion of the northwestern edge of Home Plate is prominent in the left quarter of this image, toward the south. This view is presented as a cylindrical projection with geometric seam correction.

Identification, expression, and immuno-reactivity of Sol i 2 & Sol i 4 venom proteins of queen red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae).

Science.gov (United States)

Lockwood, Stephanie A; Haghipour-Peasley, Jilla; Hoffman, Donald R; Deslippe, Richard J

2012-10-01

We report on two low-molecular weight proteins that are stored in the venom of queen red imported fire ants (Solenopsis invicta). Translated amino acid sequences identified one protein to have 74.8% identity with the Sol i 2w worker allergen, and the other protein was found to have 96/97% identity with Sol i 4.01w/4.02w worker allergens. Both Sol i 2 and Sol i 4 queen and worker proteins were expressed using pEXP1-DEST vector in SHuffle™ T7 Express lysY Escherichia coli. Proteins were expressed at significant concentrations, as opposed to the μg/ml amounts by our previous expression methods, enabling further study of these proteins. Sol i 2q protein bound weakly to human IgE, sera pooled from allergic patients, whereas Sol i 2w, Sol i 4.01w, and Sol i 4q proteins bound strongly. Despite Sol i 2w and Sol i 2q proteins having 74.8% identity, the queen protein is less immuno-reactive than the worker allergen. This finding is consistent with allergic individuals being less sensitive to queen than worker venom. Copyright © 2012 Elsevier Ltd. All rights reserved.

Efecto del secado de los biosólidos de la planta de tratamiento de aguas residuales El Salitre (Bogotá sobre su contenido de nutrientes, metales pesados y patógenos

Directory of Open Access Journals (Sweden)

Giraldo Óscar

2006-12-01

Full Text Available

Se acondicionó el biosólido proveniente  de la planta de tratamiento de aguas residuales El Salitre, en Bogotá, para su uso agrícola o forestal, de tal manera que el producto obtenido se encontrara dentro de los límites máximos permisibles de contaminantes establecidos por la estadounidense Environmental Protection Agency (EPA y su contenido de nutrientes se afectara en la menor proporción posible. Se realizaron tratamientos térmicos a temperaturas de 50, 55, 60, 65 y 70 °C, y se determinó el contenido de coliformes totales, E. coli y Salmonella, el contenido de nutrientes totales (N, P, K y metales pesados disponibles (Cd, Cr, Cu, Mn, Ni, Pb, Zn, antes y después de cada uno de los tratamientos. Los tratamientos de secado entre 55-70 °C redujeron los coliformes totales y E. coli hasta niveles apropiados para que el biosólido pueda ser utilizado en aplicaciones forestales. Aunque los contenidos de nutrientes del producto se redujeron entre 75% y 95%, aún se considera apropiados para su utilización como fertilizante. Los metales Cu y Zn aumentaron sus contenidos disponibles después de los tratamientos, Cd y Cr no fueron detectados y los contenidos de  algunos metales pesados (Mn, Ni, Pb se redujeron con el proceso de secado. Sin embargo, para  todos  los metales los valores se encontraron por debajo de los límites establecidos por la EPA para la aplicación del biosólido en terrenos agrícolas. Se concluyó que el tratamiento de secado de biosólido puede considerarse como una opción válida para su acondicionamiento para uso forestal.

Applications of sol gel ceramic coatings

International Nuclear Information System (INIS)

Barrow, D.

1996-01-01

The sol gel method is a chemical technique in which polycrystalline ceramic films are fabricated from a solution of organometallic precursors. The technique is attractive for many industrial applications because it is a simple (films are processed in air), flexible (can be used to coat complex geometries) and cost effective (does not require expensive equipment) process. In addition, dense, high quality coatings can be achieved at much lower temperatures than is generally required for sintering bulk ceramics. In this paper the conventional sol gel method and the new datec process are reviewed and potential applications of sol gel coatings in automotive, aerospace, petrochemical, nuclear and electronic industries are discussed. (orig.)

Sensitization by UV light of α-Al2O3:C polycrystalline detectors

International Nuclear Information System (INIS)

Meira B, L. C.; Rubio F, H.; Neres de A, E.; Santos, A.

2014-08-01

This paper describes an increase in sensitivity to gamma and beta radiation on α-Al 2 O 3 :C polycrystalline detector, which has been produced by a sol-gel process, following previous exposure to ultraviolet light. The increased sensitivity of the detector as a function of the exposure time and ultraviolet wavelength was studied. Since the main luminescent centers have emission peaks at different wavelengths, selective measurements of thermoluminescent emission intensity were done, in order to investigate the possible conversion of centers as a result of the exposition to ultraviolet light. Experimental results indicate that the nature and parameters of the luminescent centers in α-Al 2 O 3 :C sol-gel material can be very different of those in α-Al 2 O 3 :C single crystal. (author)

Modification of Ti6Al4V implant surfaces by biocompatible TiO{sub 2}/PCL hybrid layers prepared via sol-gel dip coating: Structural characterization, mechanical and corrosion behavior

Energy Technology Data Exchange (ETDEWEB)

Catauro, Michelina, E-mail: michelina.catauro@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 21, 81031 Aversa (Italy); Bollino, Flavia [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 21, 81031 Aversa (Italy); Giovanardi, Roberto; Veronesi, Paolo [Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via Vivarelli 10, 41125 Modena (Italy)

2017-05-01

Surface modification of metallic implants is a promising strategy to improve tissue tolerance, osseointegration and corrosion resistance of them. In the present work, bioactive and biocompatible organic-inorganic hybrid coatings were prepared using a sol-gel dip coating route. They consist of an inorganic TiO{sub 2} matrix in which different percentages of poly(ε-caprolactone) (PCL), a biodegradable and biocompatible polymer, were incorporated. The coatings were used to modify the surface of Ti6Al4V substrates in order to improve their wear and corrosion resistance. The chemical structure of the coatings was analyzed by attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy. Coating microstructure, mechanical properties and ability to inhibit the corrosion of the substrates were evaluated as a function of the PCL amount. Scanning electron microscopy (SEM) showed that the polymer allows to obtain crack-free coatings, but when high percentages were added uncoated areas appear. Nano-indentation tests revealed that, as expected, surface hardness and elastic modulus decrease as the percentage of polymeric matrix increases, but scratch testing demonstrated that the coatings are effective in preventing scratching of the underlying metallic substrate, at least for PCL contents up to 20 wt%. The electrochemical tests (polarization curves acquired in order to evaluate the corrosion resistance) allowed to asses that the coatings have a significant effect in term of corrosion potential (E{sub corr}) but they do not significantly affect the passivation process that titanium undergoes in contact with the test solution used (modified Dulbecco's phosphate-buffered saline or DPBS). - Highlights: • Bioactive TiO{sub 2}/PCL hybrid coatings on Ti6Al4V were prepared via sol-gel dip coating. • Hybrid coatings are crack-free but when 50 wt% PCL was added, uncoated areas appear. • Coating hardness and elastic modulus decrease as the PCL percentage

Diseño de un espesador por gravedad y eras de secado para los lodos producidos en la planta de tratamiento de agua potable Acueductos La Enea Ltda.

OpenAIRE

Holguín Isaza, Carlos Andrés

2003-01-01

En el presente trabajo se realiza una caracterización de las aguas de lavado de filtros y decantadores de la planta de tratamiento de agua potable “Acueductos la Enea Ltda.”, realizándole ensayos de caudal, sólidos sedimentables y sólidos suspendidos totales. Se diseña además un sistema de espesamiento por gravedad y secado en lechos de arena y grava para los lodos producidos durante el lavado de los decantadores y filtros, por medio de los datos obtenidos a nivel de laboratorio, a nivel pilo...

Digging Movie from Phoenix's Sol 18

Science.gov (United States)

2008-01-01

The Surface Stereo Imager on NASA's Phoenix Mars Lander recorded the images combined into this movie of the lander's Robotic Arm enlarging and combining the two trenches informally named 'Dodo' (left) and 'Goldilocks.' The 21 images in this sequence were taken over a period of about 2 hours during Phoenix's Sol 18 (June 13, 2008), or the 18th Martian day since landing. The main purpose of the Sol 18 dig was to dig deeper for learning the depth of a hard underlying layer. A bright layer, possibly ice, was increasingly exposed as the digging progressed. Further digging and scraping in the combined Dodo-Goldilocks trench was planned for subsequent sols. The combined trench is about 20 centimeters (about 8 inches) wide. The depth at the end of the Sol 18 digging is 5 to 6 centimeters (about 2 inches). The Goldilocks trench was the source of soil samples 'Baby Bear' and 'Mama Bear,' which were collected on earlier sols and delivered to instruments on the lander deck. The Dodo trench was originally dug for practice in collecting and depositing soil samples. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Estudio de la cinética fisicoquímica del mango (mangifera indica l. var. tommy atkins) tratado por métodos combinados de secado

OpenAIRE

MORENO, ANGÉLICA; LEÓN, DAVID; GIRALDO, GERMAN; RIOS, EUNICE

2010-01-01

El seguimiento cinético de los parámetros de peso, actividad de agua (aw) y ganancia de sólidos solubles (ºBrix) en cubos de mango (Mangifera indica L. Var. Tommy Atkins) fueron evaluados durante los procesos de deshidratación osmótica con o sin pulso de vacío (DO y DOPV) en combinación con el secado por aire caliente (SAC) o a vacío (VAC). Se observó que la DOPV y el SAC son los métodos más efectivos ya que requieren menor tiempo de proceso para alcanzar sus niveles adecuados de humedad para...

Sol-gel synthesis of hydroxyapatite

International Nuclear Information System (INIS)

Zupanski, M.D.; Lucena, M.P.P.; Bergmann, C.P.

2010-01-01

Hydroxyapatite (HAp) has been established as the calcium phosphate based compound with most applications in the biological field. Among the numerous techniques for synthesis of HAp, the sol-gel processing route affords great control over purity and formed phases using low processing temperatures. In addition, the sol-gel approach offers an option for homogeneous HAp coating on metal substrates, as well as the ability to generate nanocrystalline powders. In this work, the sol-gel synthesis of HAp was investigated employing triethyl phosphate and calcium nitrate tetrahydrate as phosphorous and calcium precursors, respectively. The aging effect on phase composition and powder morphology of the final product was studied in terms of temperature and aging time. The powders were studied by using X-ray diffraction, Fourier transform infrared spectroscopy, particle size distribution by laser diffraction and scanning electron microscopy. (author)

Upgrades for TwinSol facility

Energy Technology Data Exchange (ETDEWEB)

O’Malley, P.D.; Bardayan, D.W.; Kolata, J.J.; Hall, M.R.; Hall, O.; Allen, J. [Physics Department, University of Notre Dame, Notre Dame, IN 46556 (United States); Becchetti, F.D. [Physics Department, U. Michigan, Ann Arbor MI 48109 (United States)

2016-06-01

TwinSol, a pair of coupled, superconducting solenoids, was one of the first devices capable of producing beams of radioactive nuclei at energies near the Coulomb barrier. A primary beam from University of Notre Dame (UND) tandem accelerator is used to bombard a primary target producing a secondary beam in flight. TwinSol is used to gather, separate, and focus the recoils. Since it was commissioned at the UND in 1997, at least 58 publications have reported data from its use and there have been hundreds of collaborators from many different countries that use this device. Currently, plans are in place at the UND to provide several upgrades to TwinSol, including a multi-cell gas production target and the possible addition of a third solenoid. Upgrades currently in progress will be discussed along with future plans.

Fast Processing of Sol-Gel TCO

NARCIS (Netherlands)

Deelen, J. van; Rem, M.; Arfsten, N.; Buskens, P.P.

2016-01-01

TCOs are usually deposited using sputtering or chemical vapor deposition, which have a yield of typically 50-75%. The sol gel method does not need low pressure and can be done with a high precursor yield in the range of 90 – 100%. Sol gel enables also the TCO function as a planarization or

Sol-gel/drop-coated micro-thick TiO{sub 2} memristors for γ-ray sensing

Energy Technology Data Exchange (ETDEWEB)

Abunahla, Heba [Department of Electrical and Computer Engineering, Khalifa University of Science, Technology and Research, Abu Dhabi (United Arab Emirates); Jaoude, Maguy Abi, E-mail: maguy.abijaoude@kustar.ac.ae [Department of Applied Mathematics and Sciences, Khalifa University of Science, Technology and Research, Abu Dhabi (United Arab Emirates); O' Kelly, Curtis J.; Mohammad, Baker [Department of Electrical and Computer Engineering, Khalifa University of Science, Technology and Research, Abu Dhabi (United Arab Emirates)

2016-12-01

Sol-gel/drop-coated micro-thick TiO{sub 2} memristors were investigated and developed for low-power radiation sensing. Devices constructed with coated aluminum (Al) electrodes exhibited unipolar I-V characteristics with dynamic turn-on voltage, and progressive R{sub OFF}/R{sub ON} ratio loss under applied bias. Endurance failure of micro-thick Al/Al stacks is ascribed to gradual passivation of Al surface resulting from an electrically-enhanced oxygen-ion diffusion. By exchanging a single Al contact with higher work function copper (Cu) metal, two distinct superimposed TiO{sub 2} phases were formed. The TiO{sub 2} coating on Al surface was carbon-contaminated and amorphous, while that on Cu was found to be additionally doped with Cu{sup (I/II)} ions resulting from the corrosion of the surface of the electrode by the amine-based gelation agent. After initial forming, the hybrid stack could achieve a bipolar memristance, with high R{sub OFF}/R{sub ON} (up to 10{sup 6}), and over 10 switching cycles at low-operating voltages (±1 V). The enhanced memristive switching properties of Al/Cu devices are explained via cooperative valence-change/electrochemical-metallization processes, involving migration of oxygen and copper species. The advanced micro-thick TiO{sub 2} memristors were exposed to Cs-137 γ-rays, providing for the first time initial insights into their radiation detection capabilities. The sensing mechanism through these devices could be actuated by synergistic radiation-induced and field-driven photo-electric effects. - Highlights: • Micro-thick TiO{sub 2} memristors with Al or Cu electrodes are advanced via sol-gel drop-coating. • Memristive switching in Al/TiO{sub 2}/Al structure is not viable due to resistance build-up. • Drop-coated Cu electrode gets corroded by ethanolamine additive, introducing Cu{sup (I/II)} cations into bulk TiO{sub 2}. • Bipolar memristance in Al/TiO{sub 2}/Cu{sup (I/II)} doped-TiO{sub 2}/Cu structure is depicted for the

Opportunity's Surroundings on Sol 1687 (Vertical)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on the 1,687th Martian day, or sol, of its surface mission (Oct. 22, 2008). Opportunity had driven 133 meters (436 feet) that sol, crossing sand ripples up to about 10 centimeters (4 inches) tall. The tracks visible in the foreground are in the east-northeast direction. Opportunity's position on Sol 1687 was about 300 meters southwest of Victoria Crater. The rover was beginning a long trek toward a much larger crater, Endeavour, about 12 kilometers (7 miles) to the southeast. This view is presented as a vertical projection with geometric seam correction.

Opportunity's Surroundings on Sol 1687 (Polar)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 360-degree view of the rover's surroundings on the 1,687th Martian day, or sol, of its surface mission (Oct. 22, 2008). Opportunity had driven 133 meters (436 feet) that sol, crossing sand ripples up to about 10 centimeters (4 inches) tall. The tracks visible in the foreground are in the east-northeast direction. Opportunity's position on Sol 1687 was about 300 meters southwest of Victoria Crater. The rover was beginning a long trek toward a much larger crater, Endeavour, about 12 kilometers (7 miles) to the southeast. This view is presented as a polar projection with geometric seam correction.

Bioactive materials for biomedical applications using sol-gel technology

International Nuclear Information System (INIS)

Gupta, Radha; Kumar, Ashok

2008-01-01

This review paper focuses on the sol-gel technology that has been applied in many of the potential research areas and highlights the importance of sol-gel technology for preparing bioactive materials for biomedical applications. The versatility of sol-gel chemistry enables us to manipulate the characteristics of material required for particular applications. Sol-gel derived materials have proved to be good biomaterials for coating films and for the construction of super-paramagnetic nanoparticles, bioactive glasses and fiberoptic applicators for various biomedical applications. The introduction of the sol-gel route in a conventional method of preparing implants improves the mechanical strength, biocompatibility and bioactivity of scaffolds and prevents corrosion of metallic implants. The use of organically modified silanes (ORMOSILS) yields flexible and bioactive materials for soft and hard tissue replacement. A novel approach of nitric-oxide-releasing sol-gels as antibacterial coatings for reducing the infection around orthopedic implants has also been discussed

Sol-gel preparation of uranium oxide spheres

International Nuclear Information System (INIS)

Dolezal, J.; Urbanek, V.

1978-01-01

Information is presented on problems of preparing nuclear fuel by the sol-gel method. Basic data on different process types are given. A more detailed description of the method of preparation of spherical particles of uranium oxide gel developed and used at the Nuclear Research Institute at Rez is given. Advantages and disadvantages of sol-gel materials are discussed in comparison with fuel materials prepared by classical precipitation methods. The feasibility of the sol-gel methods for preparing other materials is shortly mentioned and their application outlined. (author)

L'educazione di un "Architetto-Urbanista". Manuel Solà-Morales e la Pedagogia Urbana all'ETSAB / The Education of an "Architect-Urbanist". Manuel Solà-Morales and Urban Pedagogy at the ETSAB

Directory of Open Access Journals (Sweden)

Marta Caldeira

2016-10-01

Full Text Available In qualità di docente, fondatore e direttore del Laboratori d’Urbanisme de Barcelona presso la ETSAB dal 1969 al 2012, l’architetto e urbanista spagnolo Manuel Solà-Morales ha curato la riforma chiave della pedagogia urbana della scuola di Barcellona. Deciso a superare la tendenza tecnocratica che aveva contraddistinto l’architettura e la pianificazione spagnola durante l’ultimo decennio del regime di Franco, l’obiettivo di Solà-Morales fu la formazione di quello che definì l’‘architetto-urbanista’ attraverso un programma propedeutico che accorpava architettura e urbanistica in un’unica disciplina. Sotto l’egida della morfologia urbana, il nuovo corso di Urbanistica impartito dal corpo docente del LUB diede il via allo studio della città e della sua storia come base principale di ogni progetto architettonico e urbano. / As professor and founding director of the Laboratori d’Urbanisme at the ETSAB from 1969 to 2012, Manuel Solà-Morales oversaw the pivotal reform of urban pedagogy in the Barcelona school. Determined to overcome the technocratic tendency that marked Spanish architecture and planning in the final decade of Franco’s regime, Solà-Morales’ mission was to educate what he defined as the ‘architect-urbanist’ through a foundational program that unified architecture and studies of urban form as a single discipline. Under the aegis of urban morphology, the new course of Urbanística taught by LUB’s team instituted the study of the city and its history as the primary ground for every architectural and urban project.

Current and future possibilities of sol-gel process

International Nuclear Information System (INIS)

Sakka, Sumio

2004-01-01

The sol-gel method is characterized by the low temperature processing. Since this method starts from solutions, the product is essentially nanomaterials. So far, various kinds of microstructures, including dense, porous, hybrid, amorphous and crystalline microstructures have been realized. Accordingly, sol-gel materials cover a wide range of functions, such as optical, electronic, mechanical, chemical and bio-functions. Future perspectives of the sol-gel method are described in the article. (author)

Sol-gel process for thermal reactor fuel fabrication

International Nuclear Information System (INIS)

Mukerjee, S.K.

2008-01-01

Full text: Sol-gel processes have revolutionized conventional ceramic technology by providing extremely fine and uniform powders for the fabrication of ceramics. The use of this technology for nuclear fuel fabrication has also been explored in many countries. Unlike the conventional sol-gel process, sol-gel process for nuclear fuels tries to eliminate the preparation of powders in view of the toxic nature of the powders particularly those of plutonium and 233 U. The elimination of powder handling thus makes this process more readily amenable for use in glove boxes or for remote handling. In this process, the first step is the preparation of microspheres of the fuel material from a solution which is then followed by vibro-compaction of these microspheres of different sizes to obtain the required smear density of fuel inside a pin. The maximum achievable packing density of 92 % makes it suitable for fast reactors only. With a view to extend the applicability of sol-gel process for thermal reactor fuel fabrication the concept of converting the gel microspheres derived from sol-gel process, to the pellets, has been under investigation for several years. The unique feature of this process is that it combines the advantages of sol-gel process for the preparation of fuel oxide gel microspheres of reproducible quality with proven irradiation behavior of the pellet fuel. One of the important pre-requisite for the success of this process is the preparation of soft oxide gel microspheres suitable for conversion to dense pellets free from berry structure. Studies on the internal gelation process, one of the many variants of sol-gel process, for obtaining soft oxide gel microspheres suitable for gel pelletisation is now under investigation at BARC. Some of the recent findings related to Sol-Gel Microsphere Pelletisation (SGMP) in urania-plutonia and thoria-urania systems will be presented

Analysis on the factors affecting the preparation of TIO2-ADUN composite sol by sol-gel method

International Nuclear Information System (INIS)

Wang Hui; Yin Rongcai; Liu Jinhong

2010-01-01

With C 2 H 2 O 5 and water as solvent and TBT as precursor and HNO 3 as the activator and valorize, the process for preparing TiO 2 -ADUN composite Sol method was studied. The influence of different reaction conditions on Sol-Gel time was analyzed in this study. The optimal reaction condition are: reaction temperature 20-25 degree C; pH value of reaction mixture 2-5; HNO 3 value of reaction mixture 0.3-0.5 ml; molar rations of alcohol to TBT 10, of water to TBT 2-3, respectively. A concentrated ADUN solution with Ti Sol , urea, water as additive is dispersed into uniform which are prepared by external mlii. (authors)

Ingeniería básica de una planta de gasificación de lodos de EDAR para el tratamiento de 14.000 Mg/año de lodo seco

OpenAIRE

Muniesa Bastida , Blanca

2005-01-01

Actualmente dos plantas de secado de fango de EDAR deshidratado (80% de humedad) gestionadas por la empresa SGT S.A. y localizadas una en el término municipal de Rubí y la otra en Mataró producen, conjuntamente, 14.000 Mg/año de fango seco (menos del 20% de humedad). El secado se realiza a partir de los gases de escape de unos motores que consumen gas natural. Se plantea la revalorización de este fango seco, que actualmente se conduce al vertedero como residuo, mediante un proc...

Comparación de algunos métodos de procesamiento para Fonsecaea pedrosoi al microscopio electrónico de rastreo

Directory of Open Access Journals (Sweden)

José B. Yung

1995-03-01

Full Text Available Se evaluaron cuatro métodos de procesamiento para el estudio ultra estructural de hongos al microscopio electrónico de rastreo (MER. Se utilizaron microcultivos de cepas colombianas de Fonsecaea pedrosoi aisladas de lesiones de pacientes en el Instituto Dermatológico Federico Lleras Acosta, Santafé de Bogotá. Los resultados mostraron alteraciones, distorsiones o artificios en los hongos procesados por tres de los métodos utilizados, debido probablemente a los efectos físicos o químicos durante el procesamiento. Se propone el método de fijación con vapores de acroleína pura y cristales de OSO. con deshidratación y secado en alto vacío que evitó la pérdida de estructuras y conservo los arreglos característicos, presentando rapidez, fácil manipulación del espécimen y disminución de reactivos. Se destaca la importancia del MER en el estudio morfológico, estructural y taxonómico de los hongos y el uso de los vapores de acroleína para la fijación y el alto vacío para el secado, como alternativas metodológicas para el procesamiento de especímenes biológicos de difícil manipulación o que presentan fácil alteración por su composición higrófila.

Modeling SOL evolution during disruptions

International Nuclear Information System (INIS)

Rognlien, T.D.; Cohen, R.H.; Crotinger, J.A.

1996-01-01

We present the status of our models and transport simulations of the 2-D evolution of the scrape-off layer (SOL) during tokamak disruptions. This evolution is important for several reasons: It determines how the power from the core plasma is distributed on material surfaces, how impurities from those surfaces or from gas injection migrate back to the core region, and what are the properties of the SOL for carrying halo currents. We simulate this plasma in a time-dependent fashion using the SOL transport code UEDGE. This code models the SOL plasma using fluid equations of plasma density, parallel momentum (along the magnetic field), electron energy, ion energy, and neutral gas density. A multispecies model is used to follow the density of different charge-states of impurities. The parallel transport is classical but with kinetic modifications; these are presently treated by flux limits, but we have initiated more sophisticated models giving the correct long-mean-free path limit. The cross-field transport is anomalous, and one of the results of this work is to determine reasonable values to characterize disruptions. Our primary focus is on the initial thermal quench phase when most of the core energy is lost, but the total current is maintained. The impact of edge currents on the MHD equilibrium will be discussed

Sol-gel-based biosensing applied to medicinal science.

Science.gov (United States)

Moreira, Felismina T C; Moreira-Tavares, Ana P; Sales, M Goreti F

2015-01-01

Biosensors have opened new horizons in biomedical analysis, by ensuring increased assay speed and flexibility, and allowing point-of-care applications, multi-target analyses, automation and reduced costs of testing. This has been a result of many studies merging nanotechnology with biochemistry over the years, thereby enabling the creation of more suitable environments to biological receptors and their substitution by synthetic analogue materials. Sol-gel chemistry, among other materials, is deeply involved in this process. Sol-gel processing allows the immobilization of organic molecules, biomacromolecules and cells maintaining their properties and activities, permitting their integration into different transduction devices, of electrochemical or optical nature, for single or multiple analyses. Sol-gel also allows to the production of synthetic materials mimicking the activity of natural receptors, while bringing advantages, mostly in terms of cost and stability. Moreover, the biocompatibility of sol-gel materials structures of biological nature allowed the use of these materials in emerging in vivo applications. In this chapter, biosensors for biomedical applications based on sol-gel derived composites are presented, compared and described, along with current emerging applications in vivo, concerning drug delivery or biomaterials. Sol-gel materials are shown as a promising tool for current, emerging and future medical applications.

Structure/Property Relationships for Sol-gel Derived YBa2Cu3O7-d and SrTiO3 Films

Science.gov (United States)

Dawley, Jeff; Clem, Paul; Siegal, Michael; Overmyer, Don

2001-03-01

Solution deposition of c-axis oriented YBa2Cu3O7-d (YBCO) films on buffered RABiT substrates is a potential method for rapid, low cost production of superconducting tapes for power transmission and other applications. For this work, 100-250 nm thick YBCO and SrTiO3 (STO) films have been prepared by spin-coating and dip-coating sol-gel solutions onto LaAlO3 (100) and RABiT Ni (200) substrates. Biaxially textured STO coatings have been deposited on LaAlO3 and RABiT Ni by using a "templating" technique and controlling growth temperature and pO2. YBCO films grown on STO coated LaAlO3 possess comparable superconducting properties to YBCO films grown directly on LaAlO3 ( 1 MA/cm2 at 77K), indicating that a high quality STO layer does not degrade the crystalline quality of the YBCO. The effects of processing parameters on the STO buffer layer and novel processing techniques for decreasing the processing time and simplifying the integration of sol-gel YBCO with Ni substrates will be discussed. Sandia is a multiprogram laboratory operated by Sandia Corp., a Lockheed Martin Company, for the US Dept. Of Energy under contract DE-AC04-94A185000.

Silica Sol-Gel Entrapment of the Enzyme Chloro peroxidase

International Nuclear Information System (INIS)

Le, T.; Chan, S.; Ebaid, B.; Sommerhalter, M.

2015-01-01

The enzyme chloro peroxidase (CPO) was immobilized in silica sol-gel beads prepared from tetramethoxysilane. The average pore diameter of the silica host structure (∼3 nm) was smaller than the globular CPO diameter (∼6 nm) and the enzyme remained entrapped after sol-gel maturation. The catalytic performance of the entrapped enzyme was assessed via the pyrogallol peroxidation reaction. Sol-gel beads loaded with 4 μg CPO per mL sol solution reached 9-12% relative activity compared to free CPO in solution. Enzyme kinetic analysis revealed a decrease in K_cat but no changes in K_M or K_I . Product release or enzyme damage might thus limit catalytic performance. Yet circular dichroism and visible absorption spectra of transparent CPO sol-gel sheets did not indicate enzyme damage. Activity decline due to methanol exposure was shown to be reversible in solution. To improve catalytic performance the sol-gel protocol was modified. The incorporation of 5, 20, or 40% methyltrimethoxysilane resulted in more brittle sol-gel beads but the catalytic performance increased to 14% relative to free CPO in solution. The use of more acidic casting buffers (ph 4.5 or 5.5 instead of 6.5) resulted in a more porous silica host reaching up to 18% relative activity

Synthesis of phthalocyanine doped sol-gel materials

Science.gov (United States)

Dunn, Bruce

1993-01-01

The synthesis of sol-gel silica materials doped with three different types of metallophthalocyanines has been studied. Homogeneous materials of good optical quality were prepared and the first optical limiting measurements of dyes in sol-gel hosts were carried out. The properties of these solid state limiters are similar to limiters based on phthalocyanine (Pc) in solution. Sol-gel silica materials containing copper, tin and germanium phthalocyanines were investigated. The initial step in all cases was to prepare silica sols by the sonogel method using tetramethoxy silane (TMOS), HCl and distilled water. Thereafter, the synthesis depended upon the specific Pc and its solubility characteristics. Copper phthalocyanine tetrasulfonic acid tetra sodium salt (CuPc4S) is soluble in water and various doping levels (1 x 10 (exp -4) M to 1 x 10 (exp -5) M) were added to the sol. The group IV Pc's, SnPc(OSi(n-hexyl)3)2 and GePc(OSi(n-hexyl)3)2, are insoluble in water and the process was changed accordingly. In these cases, the compounds were dissolved in THF and then added to the sol. The Pc concentration in the sol was 2 x 10(exp -5)M. The samples were then aged and dried in the standard method of making xerogel monoliths. Comparative nanosecond optical limiting experiments were performed on silica xerogels that were doped with the different metallophthalocyanines. The ratio of the net excited state absorption cross section (sigma(sub e)) to the ground state cross section (sigma(sub g)) is an important figure of merit that is used to characterize these materials. By this standard the SnPc sample exhibits the best limiting for the Pc doped sol-gel materials. Its cross section ratio of 19 compares favorably with the value of 22 that was measured in toluene. The GePc materials appear to not be as useful as those containing SnPc. The GePc doped solids exhibit a higher onset energy (2.5 mj and lower cross section ratio, 7. The CuPc4S sol-gel material has a still lower cross

Sol-gel coatings on carbon/carbon composites

International Nuclear Information System (INIS)

Sim, S.M.; Krabill, R.M.; Dalzell, W.J. Jr.; Chu, P.Y.; Clark, D.E.

1986-01-01

The need for structural materials that can withstand severe environments up to 4000 0 F has promulgated the investigation of sol-gel derived ceramic and composite coatings on carbon/carbon composite materials. Alumina and zirconia sols have been deposited via thermophoresis on carbon/carbon substrates

Sol-gel applications for ceramic membrane preparation

Science.gov (United States)

Erdem, I.

2017-02-01

Ceramic membranes possessing superior properties compared to polymeric membranes are more durable under severe working conditions and therefore their service life is longer. The ceramic membranes are composed of some layers. The support is the layer composed of coarser ceramic structure and responsible for mechanical durability under filtration pressure and it is prepared by consolidation of ceramic powders. The top layer is composed of a finer ceramic micro-structure mainly responsible for the separation of components present in the fluid to be filtered and sol-gel method is a versatile tool to prepare such a tailor-made ceramic filtration structure with finer pores. Depending on the type of filtration (e.g. micro-filtration, ultra-filtration, nano-filtration) aiming separation of components with different sizes, sols with different particulate sizes should be prepared and consolidated with varying precursors and preparation conditions. The coating of sol on the support layer and heat treatment application to have a stable ceramic micro-structure are also important steps determining the final properties of the top layer. Sol-gel method with various controllable parameters (e.g. precursor type, sol formation kinetics, heat treatment conditions) is a practical tool for the preparation of top layers of ceramic composite membranes with desired physicochemical properties.

Sol-gel optical coatings for lasers: Part 1

International Nuclear Information System (INIS)

Floch, H.G.; Belleville, P.F.; Priotton, J.J.

1995-01-01

Many manufacturers and users claim that optical coatings are best prepared by physical vapor deposition technology. Others believe that sol-gel technology is an effective and competitive alternative. This article, the first of three, emphasizes sol-gel thin-film history and relates it to high-power laser technology, chemistry of the sol-gel process, production of optical coatings and deposition techniques. The second and third articles describe the preparation and performance of antireflective and highly reflective sol-gel optical coatings, respectively, that have been developed for the 1.8-MJ/500-TW (351-nm) pulsed neodymium-glass laser. This powerful laser is to be used in France's Inertial Confinement Fusion (ICF) program. It will demonstrate, at the laboratory scale, ignition of deuterium-tritium fusion fuel

Self-Healing Corrosion Protective Sol-Gel Coatings

NARCIS (Netherlands)

Abdolah Zadeh, M.

2016-01-01

Inspired by the state of the art and the recent advances in the field of self-healing corrosion protective coatings, the thesis entitled “Self-healing corrosion protective sol-gel coatings” addresses novel routes to self-healing corrosion protective sol-gel coatings via extrinsic and intrinsic

Screen-printable sol-gel enzyme-containing carbon inks.

Science.gov (United States)

Wang, J; Pamidi, P V; Park, D S

1996-08-01

Enzymes usually cannot withstand the high-temperature curing associated with the thick-film fabrication process and require a separate immobilization step in connection with the production of single-use biosensors. We report on the development of sol-gel-derived enzyme-containing carbon inks that display compatibility with the screen-printing process. Such coupling of sol-gel and thick-film technologies offers a one-step fabrication of disposable enzyme electrodes, as it obviates the need for thermal curing. The enzyme-containing sol-gel carbon ink, prepared by dispersing the biocatalyst, along with the graphite powder and a binder, within the sol-gel precursors, is cured very rapidly (10 min) at low temperature (4 °C). The influence of the ink preparation conditions is explored, and the sensor performance is evaluated in connection with the incorporation of glucose oxidase or horseradish peroxidase. The resulting strips are stable for at least 3 months. Such sol-gel-derived carbon inks should serve as hosts for other heat-sensitive biomaterials in connection with the microfabrication of various thick-film biosensors.

Sol-gel based oxidation catalyst and coating system using same

Science.gov (United States)

Watkins, Anthony N. (Inventor); Leighty, Bradley D. (Inventor); Oglesby, Donald M. (Inventor); Patry, JoAnne L. (Inventor); Schryer, Jacqueline L. (Inventor)

2010-01-01

An oxidation catalyst system is formed by particles of an oxidation catalyst dispersed in a porous sol-gel binder. The oxidation catalyst system can be applied by brush or spray painting while the sol-gel binder is in its sol state.

Fast temperature fluctuation measurements in SOL of tokamak TCV

DEFF Research Database (Denmark)

Horacek, J.; Nielsen, Anders Henry; Pitts, R.A.

to compare the statistical character of turbulence in the SOL particle flux on TCV with results from the 2D fluid electrostatic model ESEL [2][4]. Using results from the fast sweeping, similar comparisons can now be made with the fluctuating Te and will be described in this contribution. We also present...... basic statistics derived from the Te time series obtained at different radii in the SOL plasma and show, in particular, that the relationship between higher moments of the probability distribution function from both experimental and simulated Te’s may be well described by the Beta probability...... distribution function, introduced for SOL turbulence in [5]. The fast Te capability also allows the SOL response to Edge Localised Modes (ELMs) to be studied and new results will be presented for the far SOL Te response during Type III ELMs....

Sensitization by UV light of α-Al{sub 2}O{sub 3}:C polycrystalline detectors

Energy Technology Data Exchange (ETDEWEB)

Meira B, L. C.; Rubio F, H.; Neres de A, E. [Centro de Desenvolvimento da Tecnologia Nuclear - CNEN, Laboratorio de Dosimetria Termoluminicente, Av. Antonio Carlos 6627, Campus UFMG, CEP 31270-901, Belo Horizonte (Brazil); Santos, A., E-mail: hrf@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear - CNEN, Laboratorio de Microesferas Gel, Av. Antonio Carlos 6627, Campus UFMG, CEP 31270-901, Belo Horizonte (Brazil)

2014-08-15

This paper describes an increase in sensitivity to gamma and beta radiation on α-Al{sub 2}O{sub 3}:C polycrystalline detector, which has been produced by a sol-gel process, following previous exposure to ultraviolet light. The increased sensitivity of the detector as a function of the exposure time and ultraviolet wavelength was studied. Since the main luminescent centers have emission peaks at different wavelengths, selective measurements of thermoluminescent emission intensity were done, in order to investigate the possible conversion of centers as a result of the exposition to ultraviolet light. Experimental results indicate that the nature and parameters of the luminescent centers in α-Al{sub 2}O{sub 3}:C sol-gel material can be very different of those in α-Al{sub 2}O{sub 3}:C single crystal. (author)

New insights into uranium (VI) sol-gel processing

International Nuclear Information System (INIS)

King, C.M.; Thompson, M.C.; Buchanan, B.R.; King, R.B.; Garber, A.R.

1990-01-01

Nuclear Magnetic Resonance (NMR) investigations on the Oak Ridge National Laboratory process for sol-gel synthesis of microspherical nuclear fuel (UO 2 ), has been extremely useful in sorting out the chemical mechanism in the sol-gel steps. 13 C, 15 N, and 1 H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C 6 H 12 N 4 ) has revealed near quantitative stability of this adamantane-like compound in the sol-gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. 17 O NMR of uranyl (UO 2 ++ ) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, [(UO 2 ) 3 (μ 3 -O)(μ 2 -OH) 3 ] + , induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results will be presented to illustrate that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH + is occluded as an ''intercalation'' cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH 4 ) 2 [(UO 2 ) 8 O 4 (OH) 10 ] · 8H 2 O. This compound is the precursor to sintered UO 2 ceramic fuel. 23 refs., 10 figs

[Basic Studies on Locoregional Injection of a Newly Designed Chitin Sol].

Science.gov (United States)

Chiba, Takehiro; Sugitachi, Akio; Kume, Kouhei; Segawa, Takenori; Nishinari, Yutaka; Ishida, Kaoru; Noda, Hironobu; Nishizuka, Satoshi; Kimura, Yusuke; Koeda, Keisuke; Sasaki, Akira

2015-11-01

Systemic chemotherapy in advanced cancer cases often provokes serious adverse events. We aimed to examine the fundamental properties and efficacy of a novel chitin sol, an anti-cancer agent with minor side effects designed to avoid the adverse effects of chemotherapy and enhance the QOL and ADL of patients. DAC-70 was used to create the novel agent termed DAC-70 sol. The anti-proliferative activity was assayed by the WST method using different types of cell lines. The anti-cancer efficacy of the novel agent was examined using cancer-bearing mice. DAC-70 sol was easily injectable through a 21-G needle. The sol suppressed proliferation of the cells in vitro. Intra-tumor injection of DAC-70 sol inhibited the rapid growth of solid tumors in the mice. CDDP-loaded DAC-70 sol, CDDP/DAC-70 sol, successfully controlled malignant ascites in the mice (psol and CDDP/DAC-70 sol is clinically useful as novel cancer chemotherapy for advanced cases. This warrants further clinical studies in cancer chemotherapy.

Vanadium dioxide formed by the sol-gel process

International Nuclear Information System (INIS)

Potember, R.S.; Speck, K.R.; Hu, H.S.

1990-01-01

This patent describes a process for the deposition of a crystalline vanadium dioxide thin film. It comprises: providing a solution comprising a vanadium tetraalkoxide and solvent; allowing hydrolysis and condensation reactions to progressively form a homogeneous sol from the solution, applying a coating of the sol to the substrate; allowing a gel to form from the sol on the substrate by evaporating the solvent; dehydrating the gel by heat treatment under an inert atmosphere to form the crystalline vanadium dioxide film

Silica scintillating materials prepared by sol-gel methods

International Nuclear Information System (INIS)

Werst, D.W.; Sauer, M.C. Jr.; Cromack, K.R.; Lin, Y.; Tartakovsky, E.A.; Trifunac, A.D.

1993-01-01

Silica was investigated as a rad-hard alternative to organic polymer hosts for organic scintillators. Silica sol-gels were prepared by hydrolysis of tetramethoxysilane in alcohol solutions. organic dyes were incorporated into the gels by dissolving in methanol at the sol stage of gel formation. The silica sol-gel matrix is very rad-hard. The radiation stability of silica scintillators prepared by this method is dye-limited. Transient radioluminescence was measured following excitation with 30 ps pulses of 20 MeV electrons

Fluorescence of Pentavalent Chromium in SiO2 Sol-Gel Glasses

Science.gov (United States)

Jia, Weiyi; Castro, Lymari; Wang, Yanyun; Liu, Huimin

1998-01-01

Chromium ions are very attractive to optical spectroscopy and laser physics. It is well known that the first laser in the history is a ruby laser activated with Cr(3+). It was found in early nineties that Cr(4+) was also an interesting lasing ion in the near infrared, and various Cr(4+) lasers have been developed. Very recently, it was reported that Cr(2+) doped in CdSe crystals showed lasing action in the infrared. The above achievement have stimulated an interest in searching for Cr(5+) and investigating its optical properties. Cr(5+) is isoelectronic with Ti(3+) and V(4+), having electron configuration 3d1. Ti(3+) is the active center of commercial cw and femtosecond sapphire lasers, tunable in the range 680-1100 nm. V(4+) doped in YAlO3 and Al2O3 showed broad band emission near 635 nm. Although EPR results of Cr(5+) were reported, the optical properties were less studied. Herren et al. reported an observation of luminescence from Cr doped in SiO2 sol-gel glass. The luminescence spectrum was assigned to pentavalent ions in their first paper, and later it was identified to be the emission from the charge transfer transition of Cr(6+). The first observation of photoluminescence from octahedrally coordinated Cr(5+) in BaCaMg aluminate glasses was reported very recently. In this work, we report luminescence results of Cr doped SiO2 sol-gel glasses. The fluorescence spectra are very different from Herrens' results, and we believe it originates from pentavalent Cr.

La microflore des sols du vignoble de Touraine

Directory of Open Access Journals (Sweden)

Claude Cuinier

1975-12-01

Full Text Available L'étude microbiologique des sols du vignoble porte sur trois années. Les déterminations quantitatives des bactéries, champignons, actinomycètes et des groupes fonctionnels des cycles de l'azote, du carbone et du soufre sont effectuées au cours de trois périodes du cycle végétatif de la vigne. Des variations saisonnières et annuelles sont observées. La microflore des sols viticoles est comparée à celle d'autres sols. Elle est au moins aussi riche et se distingue par son caractère plus aérobie. De grands écarts dans la composition microbiologique sont apparus entre des sols viticoles différant par leurs caractéristiques physiques et chimiques.

Turbulent transport regimes and the SOL heat flux width

Science.gov (United States)

Myra, J. R.; D'Ippolito, D. A.; Russell, D. A.

2014-10-01

Understanding the responsible mechanisms and resulting scaling of the scrape-off layer (SOL) heat flux width is important for predicting viable operating regimes in future tokamaks, and for seeking possible mitigation schemes. Simulation and theory results using reduced edge/SOL turbulence models have produced SOL widths and scalings in reasonable accord with experiments in many cases. In this work, we attempt to qualitatively and conceptually understand various regimes of edge/SOL turbulence and the role of turbulent transport in establishing the SOL heat flux width. Relevant considerations include the type and spectral characteristics of underlying instabilities, the location of the gradient drive relative to the SOL, the nonlinear saturation mechanism, and the parallel heat transport regime. Recent SOLT turbulence code results are employed to understand the roles of these considerations and to develop analytical scalings. We find a heat flux width scaling with major radius R that is generally positive, consistent with older results reviewed in. The possible relationship of turbulence mechanisms to the heuristic drift mechanism is considered, together with implications for future experiments. Work supported by US DOE grant DE-FG02-97ER54392.

Effect of thickness on structural, electrical, optical and magnetic properties of Co and Al doped ZnO films deposited by sol-gel route

Energy Technology Data Exchange (ETDEWEB)

Sharma, Mamta [Department of Electronic Science, University of Delhi South Campus, New Delhi 110021 (India); Mehra, R.M. [Department of Electronic Science, University of Delhi South Campus, New Delhi 110021 (India)], E-mail: rammehra2003@yahoo.com

2008-12-30

This paper reports deposition and characterization of Zn{sub 0.94}Co{sub 0.05}Al{sub 0.01}O films of thickness ranging from 70 nm to 400 nm. These films were deposited on a glass (Corning, 7059) substrate using sol-gel route. The films have been characterized to study their structural, electrical, optical and magnetic properties. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to study the crystallinity and growth mode of the films. The films deposited up to a thickness of 200 nm showed improvement in crystallinity and preferential c-axis orientation. A transition in the growth mode from vertical (c-axis) to lateral (a and b-axis) was observed with further increase in the thickness of the film. The average transmittance of the films for thickness less than 200 nm was above 80% in the visible region which decreased at higher thickness of the film. The resistivity of the film was found to decrease with increase in thickness up to 200 nm. Ferromagnetism, at room temperature, was confirmed for 200 nm and 400 nm thick films.

Effect of thickness on structural, electrical, optical and magnetic properties of Co and Al doped ZnO films deposited by sol-gel route

International Nuclear Information System (INIS)

Sharma, Mamta; Mehra, R.M.

2008-01-01

This paper reports deposition and characterization of Zn 0.94 Co 0.05 Al 0.01 O films of thickness ranging from 70 nm to 400 nm. These films were deposited on a glass (Corning, 7059) substrate using sol-gel route. The films have been characterized to study their structural, electrical, optical and magnetic properties. X-ray diffraction (XRD) and atomic force microscopy (AFM) were used to study the crystallinity and growth mode of the films. The films deposited up to a thickness of 200 nm showed improvement in crystallinity and preferential c-axis orientation. A transition in the growth mode from vertical (c-axis) to lateral (a and b-axis) was observed with further increase in the thickness of the film. The average transmittance of the films for thickness less than 200 nm was above 80% in the visible region which decreased at higher thickness of the film. The resistivity of the film was found to decrease with increase in thickness up to 200 nm. Ferromagnetism, at room temperature, was confirmed for 200 nm and 400 nm thick films.

Structure changes in the sol-gel systems of hydrated oxides

International Nuclear Information System (INIS)

Gaponov, Y.A.; Karakchiev, L.G.; Lyakhov, N.Z.; Tolochko, B.P.; Ito, K.; Amemiya, Y.

1998-01-01

Sols of hydrated aluminium oxide, hydrated zirconium oxide and their mixtures were investigated during the xerogel-amorphous-product-crystalline-product transition by SAXS using synchrotron radiation. In the different temperature regions certain changes in structure and morphology were observed. Some correlation between the characteristics of the initial sols and their mixtures (the size and shape of the pores) was observed. In the temperature region 298-1173 K the characteristics of the mixed sol are defined by the characteristics of the initial sols

Biocatalysis with Sol-Gel Encapsulated Acid Phosphatase

Science.gov (United States)

Kulkarni, Suhasini; Tran, Vu; Ho, Maggie K.-M.; Phan, Chieu; Chin, Elizabeth; Wemmer, Zeke; Sommerhalter, Monika

2010-01-01

This experiment was performed in an upper-level undergraduate biochemistry laboratory course. Students learned how to immobilize an enzyme in a sol-gel matrix and how to perform and evaluate enzyme-activity measurements. The enzyme acid phosphatase (APase) from wheat germ was encapsulated in sol-gel beads that were prepared from the precursor…

Sol-gel synthesis of 45S5 bioglass – Prosthetic coating by electrophoretic deposition

Directory of Open Access Journals (Sweden)

Faure Joel

2013-11-01

Full Text Available In this work, the 45S5 bioactive glass has been prepared by the sol-gel process using an organic acid catalyst instead of nitric acid usually used. The physico-chemical and structural characterizations confirmed and validated the elemental composition of the resulting glass. In addition, the 45S5 bioactive glass powder thus obtained was successfully used to elaborate by electrophoretic deposition a prosthetic coating on titanium alloy Ti6Al4V.

Preparation and characterization of sol-gel derived TiO2 films

International Nuclear Information System (INIS)

Hong, Y.J.; Brungs, M.P.; Chaplin, R.P.; Sizgek, E.

2001-01-01

Crack-free transparent titania films have been prepared through a new sol-gel process combined with hydrogen peroxide treatment. Hydrogen peroxide and HCl were used to dissolve amorphous titania powder which is obtained by drying common sol-gel titania sol. The peroxo-titania sol produced a thicker film than the common sol-gel titania sol due to a higher degree of condensation. Film thickness could be further increased by controlled drying conditions of the amorphous titania powder or 'aging' the sol. Polyethylene glycol (PEG) and chemical additives were effective in controlling condensation rate by preventing rapid condensation during curing of the film. When these two components were incorporated, it was possible to create a 0.5μm transparent film and PEG could also control the porosity of the film. The cured film was analysed by XRD and Raman spectroscopy. In order to measure the reflective index and thickness of the titania film, an ellipsometer was used. Copyright (2001) The Australian Ceramic Society

Silica- and germania-based dual-ligand sol-gel organic-inorganic hybrid sorbents combining superhydrophobicity and π-π interaction. The role of inorganic substrate in sol-gel capillary microextraction.

Science.gov (United States)

Seyyal, Emre; Malik, Abdul

2017-04-29

Principles of sol-gel chemistry were utilized to create silica- and germania-based dual-ligand surface-bonded sol-gel coatings providing enhanced performance in capillary microextraction (CME) through a combination of ligand superhydrophobicity and π-π interaction. These organic-inorganic hybrid coatings were prepared using sol-gel precursors with bonded perfluorododecyl (PF-C 12 ) and phenethyl (PhE) ligands. Here, the ability of the PF-C 12 ligand to provide enhanced hydrophobic interaction was advantageously combined with π-π interaction capability of the PhE moiety to attain the desired sorbent performance in CME. The effect of the inorganic sorbent component on microextraction performance of was explored by comparing microextraction characteristics of silica- and germania-based sol-gel sorbents. The germania-based dual-ligand sol-gel sorbent demonstrated superior CME performance compared to its silica-based counterpart. Thermogravimetric analysis (TGA) of the created silica- and germania-based dual-ligand sol-gel sorbents suggested higher carbon loading on the germania-based sorbent. This might be indicative of more effective condensation of the organic ligand-bearing sol-gel-active chemical species to the germania-based sol-gel network (than to its silica-based counterpart) evolving in the sol solution. The type and concentration of the organic ligands were varied in the sol-gel sorbents to fine-tune extraction selectivity toward different classes of analytes. Specific extraction (SE) values were used for an objective comparison of the prepared sol-gel CME sorbents. The sorbents with higher content of PF-C 12 showed remarkable affinity for aliphatic hydrocarbons. Compared to their single-ligand sol-gel counterparts, the dual-ligand sol-gel coatings demonstrated significantly superior CME performance in the extraction of alkylbenzenes, providing up to ∼65.0% higher SE values. The prepared sol-gel CME coatings provided low ng L -1 limit of detections (LOD

Sol-Gel Manufactured Energetic Materials

Science.gov (United States)

Simpson, Randall L.; Lee, Ronald S.; Tillotson, Thomas M.; Hrubesh, Lawrence W.; Swansiger, Rosalind W.; Fox, Glenn A.

2005-05-17

Sol-gel chemistry is used for the preparation of energetic materials (explosives, propellants and pyrotechnics) with improved homogeneity, and/or which can be cast to near-net shape, and/or made into precision molding powders. The sol-gel method is a synthetic chemical process where reactive monomers are mixed into a solution, polymerization occurs leading to a highly cross-linked three dimensional solid network resulting in a gel. The energetic materials can be incorporated during the formation of the solution or during the gel stage of the process. The composition, pore, and primary particle sizes, gel time, surface areas, and density may be tailored and controlled by the solution chemistry. The gel is then dried using supercritical extraction to produce a highly porous low density aerogel or by controlled slow evaporation to produce a xerogel. Applying stress during the extraction phase can result in high density materials. Thus, the sol-gel method can be used for precision detonator explosive manufacturing as well as producing precision explosives, propellants, and pyrotechnics, along with high power composite energetic materials.

Spatially resolved speckle-correlometry of sol-gel transition

Science.gov (United States)

Isaeva, A. A.; Isaeva, E. A.; Pantyukov, A. V.; Zimnyakov, D. A.

2018-04-01

Sol-gel transition was studied using the speckle correlometry method with a localized light source and spatial filtering of backscattered radiation. Water solutions of technical or food gelatin with added TiO2 nanoparticles were used as studied objects. Structural transformation of "sol-gel" system was studied at various temperatures from 25°C to 50°C using analysis of the correlation and structure functions of speckle intensity fluctuations. The characteristic temperatures of "sol - gel" transition were evaluated for studied systems. Obtained results can be used for various applications in biomedicine and food industry.

Time for a Change; Spirit's View on Sol 1843

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends. The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.' The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate. This view is presented as a cylindrical projection with geometric seam correction.

Effect of SiO2 concentration in silica sol on interface reaction during titanium alloy investment casting

Directory of Open Access Journals (Sweden)

Ya-meng Wei

2018-01-01

Full Text Available Using silica sol as a binder for titanium investment casting is very attractive due to its good stability and reasonable cost as compared with yttrium sol and zirconium sol. However, the mechanism of interface reaction in the related system remains unclear. In this investigation, the interface reaction between Y2O3-SiO2 (Y-Si shell mold and titanium alloys was studied. A group of shell molds were prepared by using Y2O3 sand and silica sol with different contents of SiO2. Ti-6Al-4V alloy was cast under vacuum by gravity casting through cold crucible induction melting (CCIM method. Scanning electron microscopy (SEM and energy dispersive x-ray spectroscopy (EDS were employed to characterize the micromorphology and composition of the reaction area, respectively. X-ray photoelectron spectroscopy (XPS was used to confirm the valence state of relevant elements. White light interferometer (WLI was used to obtain the surface topography of Y-Si shells. The results show that the thickness of reaction layers is below 3 μm when the SiO2 content of silica sol is below 20wt.%. Whereas, when the SiO2 content increases to 25wt.%, the thickness of the reaction layer increases sharply to about 15 μm. There is a good balance between chemical inertness and mechanical performance when the SiO2 content is between 15 and 20wt.%. Moreover, it was found that the distribution of SiO2 and the roughness at the surface of the shell are the key factors that determine the level of reaction.

Abstracts of International Conference on Sol-Gel Materials' 04

International Nuclear Information System (INIS)

2004-01-01

International Conference on Sol-Gel Materials '04 was an important forum for discussion on problems related to sol-gel processes applied for preparation materials with special physical properties and assignment. The application of sol-gel materials as phosphors, surface coatings, sensors, waveguides, medical implants, joints etc. has been presented. Preparation conditions, methods of physical characterization as well as optimal chemical composition of such materials have been also discussed in detail

Highly stable and imperceptible electronics utilizing photoactivated heterogeneous sol-gel metal-oxide dielectrics and semiconductors.

Science.gov (United States)

Jo, Jeong-Wan; Kim, Jaekyun; Kim, Kyung-Tae; Kang, Jin-Gu; Kim, Myung-Gil; Kim, Kwang-Ho; Ko, Hyungduk; Kim, Jiwan; Kim, Yong-Hoon; Park, Sung Kyu

2015-02-18

Incorporation of Zr into an AlOx matrix generates an intrinsically activated ZAO surface enabling the formation of a stable semiconducting IGZO film and good interfacial properties. Photochemically annealed metal-oxide devices and circuits with the optimized sol-gel ZAO dielectric and IGZO semiconductor layers demonstrate the high performance and electrically/mechanically stable operation of flexible electronics fabricated via a low-temperature solution process. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transporte de Materia con Reducción de Volumen en el Interior de Sólidos Paralelepípedos Mass Transport with Shrinkage Inside Parallelepiped Solids

OpenAIRE

J. J. S Nascimento; B. J. T. Mederos; F. A. Belo; A. G. B. de Lima

2005-01-01

Se describe un modelo matemático tridimensional transitorio aplicado al fenómeno de difusión de agua en el interior de sólidos paralelepípedos. Se utilizó el método de los volúmenes finitos considerando propiedades térmica y mecánicas constantes, equilibrio en la superficie y reducción de volumen del material. El modelo fue utilizado para estudiar el proceso de secado de un ladrillo de cerámica. Se muestran los resultados de la cinética de secado y la distribución del contenido de humedad en ...

Opportunity's Surroundings on Sol 1818

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends. The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view. The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock. This view is presented as a cylindrical projection with geometric seam correction.

Sol-gel materials for optofluidics - process and applications

DEFF Research Database (Denmark)

Mikkelsen, Morten Bo Lindholm

2011-01-01

This Ph.D. thesis is concerned with the use of sol-gel materials in optofluidic applications and the physics of DNA molecules in nanoconfinement. The bottom-up formation of solid material, which is provided by the sol-gel process, enables control of the chemical composition and porosity...... of the material. At early stages of gelation, thin gel coatings can be structured by nanoimprint lithography, and purely inorganic silica materials can be obtained by subsequent thermal annealing. The sol-gel process thus constitutes a unique method for nanofabrication of silica materials of special properties....... In this work, sol-gel silica is introduced as a new material class for the fabrication of lab-on-a-chip devices for DNA analysis. An imprint process with a rigid, non-permeable stamp was developed, which enabled fabrication of micro- and nanofluidic silica channels in a single process step without use of any...

Nickel-based xerogel catalysts: Synthesis via fast sol-gel method and application in catalytic hydrogenation of p-nitrophenol to p-aminophenol

Energy Technology Data Exchange (ETDEWEB)

Feng, Jin; Wang, Qiang; Fan, Dongliang; Ma, Lirong; Jiang, Deli; Xie, Jimin, E-mail: xiejm391@sohu.com; Zhu, Jianjun, E-mail: zhjj029@sina.com

2016-09-30

Graphical abstract: In order to investigate the roles of three-dimensional network structure and calcium on Ni catalysts, the Ni, Ni-Al{sub 2}O{sub 3}, Ni-Ca-Al{sub 2}O{sub 3} xerogel catalysts were successfully synthesized via the fast sol-gel process and chemical reduction method. - Highlights: • Epoxide-driven sol-gel and chemical reduction method subsequently were used to prepare Ni, Ni-Al{sub 2}O{sub 3} and Ni-Ca-Al{sub 2}O{sub 3} catalysts. • Three-dimensional network structure of the gel was employed to adjust the size and distribution of Ni nanoparticles. • Calcium was employed to shorten the gelation time, improve the nickel dispersion, decrease thenickel particle size and strengthen the Ni-Al{sub 2}O{sub 3} interaction. • The rate constants of Ni-Ca-Al2O3 catalysts (2.85 × 10{sup −3} s{sup −1}) is 2.8 times higher than the Ni catalysts (1.02 × 10{sup −3} s{sup −1}) and 2 times higher than the Ni-Al{sub 2}O{sub 3} catalysts(1.42 × 10{sup −3} s{sup −1}). • After 5 cycles, the conversion of PNP to PAP catalyzed by Ni, Ni-Al{sub 2}O{sub 3}, Ni-Ca-Al{sub 2}O{sub 3} remained 85%, 82%, 80%, respectively. - Abstract: In order to investigate the roles of three-dimensional network structure and calcium on Ni catalysts, the Ni, Ni-Al{sub 2}O{sub 3}, Ni-Ca-Al{sub 2}O{sub 3} xerogel catalysts were successfully synthesized via the fast sol-gel process and chemical reduction method. The crystal structure of three different catalysts was observed with X-ray powder diffraction (XRD). Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and nitrogen adsorption-desorption were employed to investigate the role of network structure of xerogel catalysts and the size distribution of Ni nanoparticles. The catalyst composition was determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) measurement and energy-dispersive X-ray spectroscopy (EDS). Temperature-programmed reduction (TPR) experiments were carried

Combining Pre- and Post-Nucleation Trajectories for the Synthesis of High FAU-Content Faujasite Nanocrystals from Organic-Free Sols

Energy Technology Data Exchange (ETDEWEB)

Khaleel, Maryam; Xu, Wenqian; Lesch, David A.; Tsapatsis, Michael

2016-06-28

The effects of synthesis conditions on the FAU/EMT content and the size of nanocrystals, formed from inorganic aluminosilicate sols, were investigated. High resolution transmission electron microscopy imaging and comparison of experimental X-ray diffraction patterns with simulations demonstrated that all materials made starting from synthesis mixtures in the composition range (1.8-33) SiO2: 1 Al2O3: (2.7-33) Na2O: (41-1000) H2O contain FAU/EMT intergrowths. Compositions with low water content increase the FAU fraction up to 0.8 but the crystal size exceeds 100 nm. Extension of the higher FAU purity to nanocrystals was achieved only by first mixing the sol at high water content compositions that favor nanocrystal formation and then - after a certain time - lowering by freeze-drying the water to levels favoring the formation of FAU. Cryogenic transmission electron microscopy and small angle X-ray scattering from representative optically clear and colloidally stable precursor sols (aged and crystallized at ambient temperature) reveal the formation of amorphous aggregates before the detection of crystals, in agreement with earlier findings and an existing model for the aggregative growth of the zeolite MFI. The presence of these amorphous aggregates coincides with the aforementioned state of sol that preserves the original trajectory towards nano-crystals after the pronounced reduction of water content by freeze-drying. If water reduction by freeze-drying is applied earlier (before the detection of amorphous aggregates), the sol follows the low water content trajectory towards larger crystals. Despite this memory effect, the sol at this stage is still agnostic towards FAU or EMT formation, the relative content of which is dominantly determined by the final water content. These findings demonstrate that it is possible to combine the effects of pre-and post-nucleation sol composition to steer crystal size and crystal structure, respectively. They confirm precursor

Structural Evolution and Stability of Sol-Gel Biocatalysts

International Nuclear Information System (INIS)

Rodgers, L.E.; Foster, L.J.R.; Holden, P.J.; Knott, R.B.; Bartlett, J.B.

2005-01-01

Full text: Immobilisation strategies for catalytic enzymes are important as they allow reuse of the biocatalysts. Sol-gel materials have been used to immobilise Candida antarctica lipase B (CALB), a commonly used industrial enzyme with a known crystal structure. The sol-gel bioencapsulate is produced through the condensation of suitable metal alkoxides in the presence of CALB, yielding materials with controlled pore sizes, volume and surface chemistry. Sol-gel matrices have been shown to prolong the catalytic life and enhance the activity of CALB, although the molecular basis for this effect has yet to be elucidated due to the limitations of analysis techniques applied to date. Small angle neutron scattering (SANS) allows such multicomponent systems to be characterised through contrast matching. In the sol-gel bioencapsulate system, at the contrast match point for silica, residual scattering intensity is due to the CALB and density fluctuations in the matrix. A SANS contrast variation series found the match point for the silica matrix, both with and without enzyme present, to be around 35 percent. The model presented here proposes a mechanism for the interaction between CALB and the surrounding sol-gel matrix, and the observed improvement in enzyme activity and matrix strength. The SANS protocol developed here may be applied more generally to bioencapsulates. (authors)

Synthesis by sol-gel and characterization of catalysts Ag/Al2O3- CeO2 for the elimination of nitric oxide

International Nuclear Information System (INIS)

Zayas R, M.L.

2005-01-01

The environmental pollution is one from the big problems to solve at the present time, because the quality of the alive beings life is affected. For such reason, more clean and economic technologies are required, that it conduces to develop new catalytic alternatives to diminish the nitrogen oxides that due to its chemical processes in the environment contribute considerably in the air pollution. The main objective of the present work, is the preparation and characterization of catalytic materials with base of silver supported in simple and mixed aluminium oxides (Al 2 O 3 ) and Cerium oxide (CeO 2 ), and its catalytic evaluation that through of the reduction of nitric oxide (NO) using hydrogen (H 2 ) as reducer agent. It was synthesized alumina (Al 2 O 3 ) and Cerium oxide (CeO 2 ) and mixed oxides (Al 2 O 3 - CeO 2 ), by the sol-gel method and the cerium oxide (CeO 2 ) by precipitation of the cerium nitrate (III) hexa hydrated. The oxides were stabilized thermally at 900 C by 5 hr. The catalysts were prepared by impregnation using silver nitrate (AgNO 3 ), the nominal concentration of Ag was of 5% in weight. The catalysts were reduced at 400 C by 2 hr, in hydrogen flow of 60 cc/min. The characterization of the catalytic materials was carried out through different techniques as: nitrogen adsorption to determine the surface area BET, scanning electron microscopy (SEM) to observe the final morphology of the catalysts, X-ray diffraction (XRD) to identify the crystalline phases of the catalytic materials, Infrared spectroscopy (DRIFT) to know the structural characterization of the catalysts, reduction to programmed temperature (TPR) to evidence the interaction metal-support. The catalytic properties of the catalysts were evaluated in the model reaction NO + H 2 , to determine the activity and selectivity. The results indicate that the preparation technique, the precursors and the thermal treatments that underwent these materials influence in the catalyst and by

Evaluation of sol-gel derived Eu{sup 2+} activated SrMgAl{sub 2}SiO{sub 7} as a novel nanostructure luminescent pigment

Energy Technology Data Exchange (ETDEWEB)

Sameie, H.; Salimi, R. [Faculty of Polymer and Color Engineering, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Sabbagh Alvani, A.A., E-mail: sabbagh_alvani@aut.ac.i [Color and Polymer Research Center (CPRC), Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Sarabi, A.A. [Faculty of Polymer and Color Engineering, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Moztarzadeh, F.; Tahriri, M. [Biomaterials Group, Faculty of Biomedical Engineering, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of)

2010-12-01

A novel nanostructure pigment of Eu{sup 2+} doped SrMgAl{sub 2}SiO{sub 7} was prepared via the sol-gel route. The phase composition and condition of crystallites during heating were characterized by X-ray diffraction (XRD) analysis. Investigation of optical properties by spectrophotometer illustrated that under short ultraviolet excitation wavelength, the main emission peak occurred at about 415-420 nm. Also, relatively pure purplish blue color was observed that can be ascribed to the 4f{sup 6}5d{sup 1}({sup 2}D){yields}4f{sup 7}({sup 8}S{sub 7/2}) transition of Eu{sup 2+}. The effect of calcination temperature on the luminescence properties of the phosphors was evaluated and, also in this case, scanning electron microscope (SEM) was employed. From colorimetry results, color coordinations of phosphor shift towards the deep blue region as calcination temperature increases. Finally, grain size of products at optimum calcination temperature was estimated to be about 20-30 nm using Scherrer's equation, which was consistent with transmission electron microscopy (TEM) observations.

Periodismo gráfico entre democracia y dictadura. El Sol de Quilmes a través de sus editoriales

OpenAIRE

Alberico, Anahí; Bernat, María Sofía; Castiglione, María Belén; Taboada, Mirta

2015-01-01

El presente artículo, enmarcado en el proyecto de extensión de la Universidad Nacional de Quilmes, “Universidad por la Identidad”, realiza un primer acercamiento analítico a las editoriales del diario El Sol de la localidad mencionada. El corpus de análisis se limita a los textos correspondientes al primer semestre de 1976, es decir que abarca tanto al gobierno de María Estela Martínez de Perón como los primeros meses de la última dictadura cívico-militar. Se trabaja desde la perspe...

Modelado de Secaderos Rotatorios en Isocorriente

Directory of Open Access Journals (Sweden)

F. Castaño

2009-10-01

Full Text Available Resumen: Este trabajo presenta una metodología para el modelado de secaderos rotatorios de s ólidos en isocorriente. El planteamiento del modelo está basado tanto en ecuaciones diferenciales paramétricas como en el uso de algunas correlaciones que permiten simplificar su tratamiento. En el trabajo se muestran aspectos de modelado que son comunes a la mayoría de instalaciones de secado y se detallan algunos puntos que pueden ser particulares o específicos de cada planta en función de su configuración o del material de secado. Se muestran también los ensayos a los que hay que someter al material para la determinación de algunas expresiones analíticas imprescindibles en el modelo. Asimismo, se presenta la aplicación del modelado a una planta experimental de secado de arena. Palabras clave: Secadero rotatorio, modelado, ecuaciones diferenciales, parámetros distribuidos, coeficientes de correlación

Turismo en la Costa del Sol. Un patrimonio en revisión

Directory of Open Access Journals (Sweden)

Lourdes Royo Naranjo

2014-01-01

Full Text Available La trigésimo cuarta edición de la Feria Internacional de Turismo, FITUR (2014, ha sido considerada por muchos inversores, como el mejor reflejo de la recuperación que está experimentando el sector turístico a escala internacional. Tal es el caso de la Costa del Sol, un destino maduro de una enorme riqueza, para el que creemos necesaria, sin embargo, una reconsideración de su modelo turístico, que ponga el foco no tanto en los aspectos mercantilistas como en la puesta en valor de una producción cultural moderna ligada al ocio de masas. Producción que ha construido una realidad identitaria alternativa, aún poco explorada, y que pretendemos atender para una valoración patrimonial contemporánea. Arquitectura, cine o literatura del turismo en la Costa del Sol se convertirían en nuevos ítems para una visión más amplia, integradora y productiva, con la que acometer nuevos desafíos en el planeamiento y la promoción turística de este destino.

Opportunity's View After Long Drive on Sol 1770

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 104 meters (341 feet) on the 1,770th Martian day, or sol, of Opportunity's surface mission (January 15, 2009). Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). Prior to the Sol 1770 drive, Opportunity had driven less than a meter since Sol 1713 (November 17, 2008), while it used the tools on its robotic arm first to examine a meteorite called 'Santorini' during weeks of restricted communication while the sun was nearly in line between Mars and Earth, then to examine bedrock and soil targets near Santorini. The rover's position after the Sol 1770 drive was about 1.1 kilometer (two-thirds of a mile) south southwest of Victoria Crater. Cumulative odometry was 13.72 kilometers (8.53 miles) since landing in January 2004, including 1.94 kilometers (1.21 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008). This view is presented as a cylindrical projection with geometric seam correction.

Strength of interactions between immobilized dye molecules and sol-gel matrices.

Science.gov (United States)

Ismail, Fanya; Schoenleber, Monika; Mansour, Rolan; Bastani, Behnam; Fielden, Peter; Goddard, Nicholas J

2011-02-21

In this paper we present a new theory to re-examine the immobilization technique of dye doped sol-gel films, define the strength and types of possible bonds between the immobilized molecule and sol-gel glass, and show that the immobilized molecule is not free inside the pores as was previously thought. Immobilizing three different pH sensitive dyes with different size and functional groups inside the same sol-gel films revealed important information about the nature of the interaction between the doped molecule and the sol-gel matrix. The samples were characterized by means of ultraviolet-visible spectrophotometer (UV-VIS), thermal gravimetric analysis (TGA), mercury porosimetry (MP), nuclear magnetic resonance spectroscopy ((29)Si NMR) and field-emission environmental scanning electron microscopy (ESEM-FEG). It was found that the doped molecule itself has a great effect on the strength and types of the bonds. A number of factors were identified, such as number and types of the functional groups, overall charge, size, pK(a) and number of the silanol groups which surround the immobilized molecule. These results were confirmed by the successful immobilization of bromocresol green (BCG) after a completely polymerized sol-gel was made. The sol-gel consisted of 50% tetraethoxysilane (TEOS) and 50% methyltriethoxysilane (MTEOS) (w/w). Moreover, the effect of the immobilized molecule on the structure of the sol-gel was studied by means of a leaky waveguide (LW) mode for doped films made before and after polymerization of the sol-gel.

Sol-gel encapsulation for controlled drug release and biosensing

Science.gov (United States)

Fang, Jonathan

The main focus of this dissertation is to investigate the use of sol-gel encapsulation of biomolecules for controlled drug release and biosensing. Controlled drug release has advantages over conventional therapies in that it maintains a constant, therapeutic drug level in the body for prolonged periods of time. The anti-hypertensive drug Captopril was encapsulated in sol-gel materials of various forms, such as silica xerogels and nanoparticles. The primary objective was to show that sol-gel silica materials are promising drug carriers for controlled release by releasing Captopril at a release rate that is within a therapeutic range. We were able to demonstrate desired release for over a week from Captopril-doped silica xerogels and overall release from Captopril-doped silica nanoparticles. As an aside, the antibiotic Vancomycin was also encapsulated in these porous silica nanoparticles and desired release was obtained for several days in-vitro. The second part of the dissertation focuses on immobilizing antibodies and proteins in sol-gel to detect various analytes, such as hormones and amino acids. Sol-gel competitive immunoassays on antibody-doped silica xerogels were used for hormone detection. Calibration for insulin and C-peptide in standard solutions was obtained in the nM range. In addition, NASA-Ames is also interested in developing a reagentless biosensor using bacterial periplasmic binding proteins (bPBPs) to detect specific biomarkers, such as amino acids and phosphate. These bPBPs were doubly labeled with two different fluorophores and encapsulated in silica xerogels. Ligand-binding experiments were performed on the bPBPs in solution and in sol-gel. Ligand-binding was monitored by fluorescence resonance energy transfer (FRET) between the two fluorophores on the bPBP. Titration data show that one bPBP has retained its ligand-binding properties in sol-gel.

Pemodelan Desain Sol Sepatu dengan Inovasi Penambahan Wave Spring

Directory of Open Access Journals (Sweden)

Redyarsa Dharma Bintara

2015-07-01

Full Text Available Desain sepatu sport berkembang pesat dengan tujuan mengurangi cedera dan meningkatkankenyamanan pengguna. Pengurangan cedera dilakukan dengan cara memperbesar energi yangdiserap dari beban akibat pengguna berlari atau melompat. Pada penelitian ini dilakukanpenambahan wave spring yang digunakan sebagai mekanisme penyerap beban.Pemodelandilakukan pada sol sepatu dengan menggunakan bantuan software finite element method (FEMAnsys 14.5 Academic. Model awal dilakukan untuk mengetahui batas deformasi sol sepatu yangakan dimanfaatkan sebagai input model berikutnya yaitu model dengan diberikan inovasipenambahan wave spring. Analisa difokuskan pada sol sepatu bagian belakang (tumit kaki.Darihasil simulasi, didapatkan bahwa penyerapan energi sol sepatu dengan penambahan wave springlebih besar daripada penyerapan energi sol sepatu tanpa penambahan wave spring, sehinggapenambahan wave spring memungkinkan untuk diaplikasikan pada sol sepatu sport.Kata kunci: Penyerapan energi, wave spring, sol sepatu. Sport shoe design had been developed rapidly with the purpose to reduce injuries and increaseuser comfort. Reduction of injury is done by enlarging the energy absorbed from the user running orjumping load. In this study, the addition of the wave spring is used as the load absorbingmechanism. The shoes sole is modeled by using finite element method (FEM software Ansys 14.5Academic. Initial model was conducted to determine the deformation boundary in soles which willbe used as input to the next model for the wave spring addition innovation. Analysis focused onshoe sole on heel foot. From the simulation results, it was found that the energy absorption shoessoles with the addition of the wave spring is greater than the energy absorption soles without theaddition of wave spring. It can be concluded that the addition of a spring wave can be applied to thesoles of sports shoes.Keywords: Energy absorb, wave spring, shoe sole, deformation boundary

Time for a Change; Spirit's View on Sol 1843 (Polar)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends. This view is presented as a polar projection with geometric seam correction. North is at the top. The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.' The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

Time for a Change; Spirit's View on Sol 1843 (Vertical)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends. This view is presented as a vertical projection with geometric seam correction. North is at the top. The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.' The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate.

Water-based sol-gel synthesis of hydroxyapatite: process development.

Science.gov (United States)

Liu, D M; Troczynski, T; Tseng, W J

2001-07-01

Hydroxyapatite (HA) ceramics were synthesized using a sol-gel route with triethyl phosphite and calcium nitrate as phosphorus and calcium precursors, respectively. Two solvents, water and anhydrous ethanol, were used as diluting media for HA sol preparation. The sols were stable and no gelling occurred in ambient environment for over 5 days. The sols became a white gel only after removal of the solvents at 60 degrees C. X-ray diffraction showed that apatitic structure first appeared at a temperature as low as 350 degrees C. The crystal size and the HA content in both gels increase with increasing calcination temperature. The type of initial diluting media (i.e., water vs. anhydrous ethanol) did not affect the microstructural evolution and crystallinity of the resulting HA ceramic. The ethanol-based sol dip-coated onto a Ti substrate, followed by calcination at 450 degrees C, was found to be porous with pore size ranging from 0.3 to 1 microm. This morphology is beneficial to the circulation of physiological fluid when the coating is used for biomedical applications. The satisfactory adhesion between the coating and substrate suggests its suitability for load-bearing uses.

Production of continuous mullite fiber via sol-gel processing

Science.gov (United States)

Tucker, Dennis S.; Sparks, J. Scott; Esker, David C.

1990-01-01

The development of a continuous ceramic fiber which could be used in rocket engine and rocket boosters applications was investigated at the Marshall Space Flight Center. Methods of ceramic fiber production such as melt spinning, chemical vapor deposition, and precursor polymeric fiber decomposition are discussed and compared with sol-gel processing. The production of ceramics via the sol-gel method consists of two steps, hydrolysis and polycondensation, to form the preceramic, followed by consolidation into the glass or ceramic structure. The advantages of the sol-gel method include better homogeneity and purity, lower preparation temperature, and the ability to form unique compositions. The disadvantages are the high cost of raw materials, large shrinkage during drying and firing which can lead to cracks, and long processing times. Preparation procedures for aluminosilicate sol-gel and for continuous mullite fibers are described.

Ultrasound-assisted sol-gel synthesis of ZrO2.

Science.gov (United States)

Guel, Marlene Lariza Andrade; Jiménez, Lourdes Díaz; Hernández, Dora Alicia Cortés

2017-03-01

Synthesis of tetragonal ZrO 2 by both conventional sol-gel and ultrasound-assisted sol-gel methods and using a non-ionic surfactant Tween-20, was performed. A porous microstructure composed of nanometric particles was observed. Tetragonal ZrO 2 was obtained using a low heat treatment temperature of powders, 500°C by both methods. A higher crystallinity and a shorter reaction time were observed when ultrasound was used in the sol-gel method due to the cavitation phenomenon. Copyright © 2016 Elsevier B.V. All rights reserved.

Ceramic protective coatings applied by sol-gel or electrophoresis

International Nuclear Information System (INIS)

Stoch, A.

1993-01-01

Sol-gel and electrophoresis are the complementary techniques which may be used for obtaining the ceramic coatings. The composition of such a coatings depends on the composition of electrophoresis bath or sol solution. Thermal treatment is used for densifying the coating and promoting the adherence of coating to the substrate. In presented work silica, silica-alumina or alumina coatings are applied by sol-gel dip coating procedure on steel, aluminium or ceramic substrates. Electrophoresis is employed for obtaining zirconia, alumina or hydroxyapatite coatings on stainless steel. (author). 7 refs

Opportunity's View After Drive on Sol 1806

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 60.86 meters (200 feet) on the 1,806th Martian day, or sol, of Opportunity's surface mission (Feb. 21, 2009). North is at the center; south at both ends. Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). Engineers designed the Sol 1806 drive to be driven backwards as a strategy to redistribute lubricant in the rovers wheels. The right-front wheel had been showing signs of increased friction. The rover's position after the Sol 1806 drive was about 2 kilometer (1.2 miles) south southwest of Victoria Crater. Cumulative odometry was 14.74 kilometers (9.16 miles) since landing in January 2004, including 2.96 kilometers (1.84 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008). This view is presented as a cylindrical projection with geometric seam correction.

Opportunity's Surroundings on Sol 1798

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top. The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock. This view is presented as a cylindrical projection with geometric seam correction.

Neutron detector based on lithiated sol-gel glass

CERN Document Server

Wallace, S; Miller, L F; Dai, S

2002-01-01

A neutron detector technology is demonstrated based on sup 6 Li/ sup 1 sup 0 B doped sol-gel glass. The detector is a sol-gel glass film coated silicon surface barrier detector (SBD). The ionized charged particles from (n, alpha) reactions in the sol-gel film enter the SBD and are counted. Data showing that gamma-ray pulse amplitudes interfere with identifying charged particles that exit the film layer with energies below the gamma-ray energy is presented. Experiments were performed showing the effect of sup 1 sup 3 sup 7 Cs and sup 6 sup 0 Co gamma rays on the SBD detector. The reaction product energies of the triton and alpha particles from sup 6 Li are significantly greater than the energies of the Compton electrons from high-energy gamma rays, allowing the measurement of neutrons in a high gamma background. The sol-gel radiation detection technology may be applicable to the characterization of transuranic waste, spent nuclear fuel and to the monitoring of stored plutonium.

Sol-Gel Chemistry for Carbon Dots.

Science.gov (United States)

Malfatti, Luca; Innocenzi, Plinio

2018-03-14

Carbon dots are an emerging class of carbon-based nanostructures produced by low-cost raw materials which exhibit a widely-tunable photoluminescence and a high quantum yield. The potential of these nanomaterials as a substitute of semiconductor quantum dots in optoelectronics and biomedicine is very high, however they need a customized chemistry to be integrated in host-guest systems or functionalized in core-shell structures. This review is focused on recent advances of the sol-gel chemistry applied to the C-dots technology. The surface modification, the fine tailoring of the chemical composition and the embedding into a complex nanostructured material are the main targets of combining sol-gel processing with C-dots chemistry. In addition, the synergistic effect of the sol-gel precursor combined with the C-dots contribute to modify the intrinsic chemo-physical properties of the dots, empowering the emission efficiency or enabling the tuning of the photoluminescence over a wide range of the visible spectrum. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Opportunity's Surroundings on Sol 1687 (Stereo)

Science.gov (United States)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11739 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11739 NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo, 360-degree view of the rover's surroundings on the 1,687th Martian day, or sol, of its surface mission (Oct. 22, 2008). The view appears three-dimensional when viewed through red-blue glasses. Opportunity had driven 133 meters (436 feet) that sol, crossing sand ripples up to about 10 centimeters (4 inches) tall. The tracks visible in the foreground are in the east-northeast direction. Opportunity's position on Sol 1687 was about 300 meters southwest of Victoria Crater. The rover was beginning a long trek toward a much larger crater, Endeavour, about 12 kilometers (7 miles) to the southeast. This panorama combines right-eye and left-eye views presented as cylindrical-perspective projections with geometric seam correction.

Sol-gel growth of vanadium dioxide

International Nuclear Information System (INIS)

Speck, K.R.

1990-01-01

This thesis examines the chemical reactivity of vanadium (IV) tetrakis(t-butoxide) as a precursor for the sol-gel synthesis of vanadium dioxide. Hydrolysis and condensation of the alkoxide was studied by FTIR spectroscopy. Chemical modification of the vanadium tetraalkoxide by alcohol interchange was studied using 51 V NMR and FTIR. Vanadium dioxide thin films and powders were made from vanadium tetrakis(t-butoxide) by standard sol-gel techniques. Post-deposition heating under nitrogen was necessary to transform amorphous gels into vanadium dioxide. Crystallization of films and powders was studied by FTIR, DSC, TGA, and XRD. Gel-derived vanadium dioxide films undergo a reversible semiconductor-to-metal phase transition near 68C, exhibiting characteristic resistive and spectral changes. The electrical resistance decreased by two to three orders of magnitude and the infrared transmission sharply dropped as the material was cycled through this thermally induced phase transition. The sol-gel method was also used to make doped vanadium dioxide films. Films were doped with tungsten and molybdenum ions to effectively lower the temperature at which the transition occurs

New Record Five-Wheel Drive, Spirit's Sol 1856 (Stereo)

Science.gov (United States)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11962 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11962 NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, 180-degree view of the rover's surroundings during the 1,856th Martian day, or sol, of Spirit's surface mission (March 23, 2009). The center of the view is toward the west-southwest. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 25.82 meters (84.7 feet) west-northwestward earlier on Sol 1856. This is the longest drive on Mars so far by a rover using only five wheels. Spirit lost the use of its right-front wheel in March 2006. Before Sol 1856, the farthest Spirit had covered in a single sol's five-wheel drive was 24.83 meters (81.5 feet), on Sol 1363 (Nov. 3, 2007). The Sol 1856 drive made progress on a route planned for taking Spirit around the western side of the low plateau called 'Home Plate.' A portion of the northwestern edge of Home Plate is prominent in the left quarter of this image, toward the south. This view is presented as a cylindrical-perspective projection with geometric seam correction.

Optical Sensors for Biomolecules Using Nanoporous Sol-Gel Materials

Science.gov (United States)

Fang, Jonathan; Zhou, Jing C.; Lan, Esther H.; Dunn, Bruce; Gillman, Patricia L.; Smith, Scott M.

2004-01-01

An important consideration for space missions to Mars is the ability to detect biosignatures. Solid-state sensing elements for optical detection of biological entities are possible using sol-gel based biologically active materials. We have used these materials as optical sensing elements in a variety of bioassays, including immunoassays and enzyme assays. By immobilizing an appropriate biomolecule in the sol-gel sensing element, we have successfully detected analytes such as amino acids and hormones. In the case of the amino acid glutamate, the enzyme glutamate dehydrogenase was the immobilized molecule, whereas in the case of the hormone cortisol, an anti-cortisol antibody was immobilized in the sensing element. In this previous work with immobilized enzymes and antibodies, excellent sensitivity and specificity were demonstrated in a variety of formats including bulk materials, thin films and fibers. We believe that the sol-gel approach is an attractive platform for bioastronautics sensing applications because of the ability to detect a wide range of entities such as amino acids, fatty acids, hopanes, porphyrins, etc. The sol-gel approach produces an optically transparent 3D silica matrix that forms around the biomolecule of interest, thus stabilizing its structure and functionality while allowing for optical detection. This encapsulation process protects the biomolecule and leads to a more "rugged" sensor. The nanoporous structure of the sol-gel matrix allows diffusion of small target molecules but keeps larger, biomolecules immobilized in the pores. We are currently developing these biologically active sol-gel materials into small portable devices for on-orbit cortisol detection

Environmentally benign sol-gel antifouling and foul-releasing coatings.

Science.gov (United States)

Detty, Michael R; Ciriminna, Rosaria; Bright, Frank V; Pagliaro, Mario

2014-02-18

Biofouling on ships and boats, characterized by aquatic bacteria and small organisms attaching to the hull, is an important global issue, since over 80000 tons of antifouling paint is used annually. This biofilm, which can form in as little as 48 hours depending on water temperature, increases drag on watercraft, which greatly reduces their fuel efficiency. In addition, biofouling can lead to microbially induced corrosion (MIC) due to H2S formed by the bacteria, especially sulfate-reducing bacteria. When the International Maritime Organization (IMO) international convention banned the use of effective but environmentally damaging coatings containing tributyl tin in 2008, the development of clean and effective antifouling systems became more important than ever. New nonbiocidal coatings are now in high demand. Scientists have developed new polymers, materials, and biocides, including new elastomeric coatings that they have obtained by improving the original silicone (polydimethylsiloxane) formulation patented in 1975. However, the high cost of silicones, especially of fluoropolymer-modified silicones, has generally prevented their large-scale diffusion. In 2009, traditional antifouling coatings using cuprous oxide formulated in copolymer paints still represented 95% of the global market volume of anti-fouling paints. The sol-gel nanochemistry approach to functional materials has emerged as an attractive candidate for creating low fouling surfaces due to the unique structure and properties of silica-based coatings and of hybrid inorganic-organic silicas in particular. Sol-gel formulations easily bind to all types of surfaces, such as steel, fiberglass, aluminum, and wood. In addition, they can cure at room temperature and form thin glassy coatings that are markedly different from thick silicone elastomeric foul-releasing coatings. Good to excellent performance against biofouling, low cure temperatures, enhanced and prolonged chemical and physical stability, ease of

Durable flame retardant finish for silk fabric using boron hybrid silica sol

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qiang-hua; Gu, Jiali; Chen, Guo-qiang [National Engineering Laboratory for Modern Silk, Soochow University (China); Xing, Tie-ling, E-mail: xingtieling@suda.edu.cn [National Engineering Laboratory for Modern Silk, Soochow University (China); Jiangsu HuaJia Group (China)

2016-11-30

Highlights: • Highly homogeneous boron hybrid silica sol flame retardant system was prepared through sol-gel method. • The silk samples treated and cross-linked by this hybrid sol and BTCA solution showed a higher limiting oxygen index (LOI) more than 31.0% and a better washing durability for more than 30 times washing. • The smoke suppression, combustion performance and thermal stability properties of the treated samples have a significant improvement. - Abstract: A hybrid silica sol was prepared via sol gel method using tetraethoxysilane (TEOS) as a precursor and boric acid (H{sub 3}BO{sub 3}) as flame retardant additive and then applied to silk fabric. In order to endow silk fabric with durable flame retardancy, 1,2,3,4-butanetetracarboxylic acid (BTCA) was used as cross-linking agent for the sake of strong linkage formation between the hybrid silica sol and silk fabric. The FT-IR and XPS analysis demonstrated the Si-O-B formation in the sol system, as well as the linkage between the sol and silk after the treatment. The limiting oxygen index (LOI) and smoke density test indicated good flame retardancy and smoke suppression of the treated silk fabrics. The micro calorimeter combustion (MCC) test and thermo gravimetric (TG) analysis showed that the treated samples had less weight loss in the high temperature and lower heat release rate when burning. The washing durability evaluation results indicated that there was a distinct improvement for the silk samples treated with BTCA even after 30 times washing. In addition, the influence of the processing order of BTCA and silica sol treatment on the limiting oxygen index (LOI) of the finished silk fabric was also investigated. And the results demonstrated that the sample treated with BTCA first and then with the silica sol exhibited better LOI value (32.3%) than that of the sample by the conversed treatment order. Moreover the tensile property of treated samples was nearly unchanged, but the handle of sol treated

Oxidación catalítica de diclorometano sobre Pd o Ni soportados en óxidos sol-gel

Directory of Open Access Journals (Sweden)

Leidy Marcela Martínez

2004-01-01

Full Text Available Se sintetizaron catalizadores sol-gel basados en paladio o níquel soportados en γ-alúmina, sílica ácida, circonia sulfatada y titania sulfatada. Los catalizadores resultantes se caracterizaron por difracción de rayos X y adsorción de nitrógeno y se evaluaron en la oxidación catalítica de diclorometano determinando el efecto de varios parámetros, entre los que se encuentran el método de síntesis, la temperatura y la acidez del soporte. El mejor catalizador (0,5% Pd impregnado en titania sulfatada se sometió a pruebas de durabilidad a 300 y 350 ºC durante 48 h. Bajo las condiciones estudiadas, los catalizadores impregnados exhibieron mayor actividad que los cogelados y los catalizadores con Pd mostraron altas conversiones principalmente a CO2 y HCl. La actividad de los catalizadores aumentó con la temperatura. Aunque los soportes γ- alúmina sol-gel y titania sulfatada también fueron activos para la reacción, una desventaja de la alúmina y la titania como soportes es la formación de trazas de CO. Los resultados indican que los catalizadores más activos y selectivos son bifuncionales. Esto es, para la descomposición de diclorometano a CO2 y HCl se requieren sitios metálicos y ácidos.

Proyecto integral Marina del Sol S.A.

Directory of Open Access Journals (Sweden)

Alfredo Palacios Barra

2008-11-01

Full Text Available El megaproyecto Marina del Sol del Gran Concepción, se emplaza en el sector del canal Ifarle a espaldas del Aeropuerto Carriel Sur en la comuna de Talcahuano. Recientemente entró a funcionar el Casino Marina del Sol, el que está inscrito en el marco de los 15 proyectos autorizados en el 2006 por la Superintendencia de Juego que buscan promover el desarrollo de este sector a nivel del país.

Asymmetric SOL Current in Vertically Displaced Plasma

Science.gov (United States)

Cabrera, J. D.; Navratil, G. A.; Hanson, J. M.

2017-10-01

Experiments at the DIII-D tokamak demonstrate a non-monotonic relationship between measured scrape-off layer (SOL) currents and vertical displacement event (VDE) rates with SOL currents becoming largely n=1 dominant as plasma is displaced by the plasma control system (PCS) at faster rates. The DIII-D PCS is used to displace the magnetic axis 10x slower than the intrinsic growth time of similar instabilities in lower single-null plasmas. Low order (n VDE instabilities observed when vertical control is disabled. Previous inquiry shows VDE asymmetry characterized by SOL current fraction and geometric parameters of tokamak plasmas. We note that, of plasmas displaced by the PCS, short displacement time scales near the limit of the PCS temporal control appear to result in larger n=1/n=2 asymmetries. Work supported under USDOE Cooperative Agreement DE-FC02-04ER54698 and DE-FG02-04ER54761.

Spirit Beside 'Home Plate,' Sol 1809

Science.gov (United States)

2009-01-01

NASA Mars Exploration Rover Spirit used its navigation camera to take the images assembled into this 120-degree view southward after a short drive during the 1,809th Martian day, or sol, of Spirit's mission on the surface of Mars (February 3, 2009). Spirit had driven about 2.6 meters (8.5 feet) that sol, continuing a clockwise route around a low plateau called 'Home Plate.' In this image, the rocks visible above the rovers' solar panels are on the slope at the northern edge of Home Plate. This view is presented as a cylindrical projection with geometric seam correction.

Optical sensing of HCl with phenol red doped sol-gels

International Nuclear Information System (INIS)

Wang Enju; Chow, Kwok-Fan; Wang Wenqun; Wong, Crystal; Yee, Cynthia; Persad, Alvin; Mann, Jonathan; Bocarsly, Andrew

2005-01-01

A dye doped sol-gel for the sensing of hydrochloric acid in solution and/or gaseous phase is described. The sol-gel is obtained by acidic hydrolysis of tetraethoxysilane (TEOS) and phenyltriethoxysilane (Ph-TriEOS) in the presence of phenol red (PR) and further spin-coating onto glass slides. The sensitive response is based on an increase of the absorption band at 510 nm of phenol red entrapped in the sol-gel casting when exposed to HCl solution or gas, due to protonation of the dye. The detection limit of the sol-gel response to moisturized gaseous HCl is below 12 ppm, and its response to HCl in solution falls in the range of 0.01-6 M. The sol-gel coating has a response time of less than 40 s in steady-state, and life-time of more than a year. Weak acids such as acetic acid, benzoic acid, salicylate acid, citrate acid, and carbonic acid do not interfere the response. The responses in acid solutions are completely reversible. In the gaseous phase, response of HCl appears to be moisture sensitive

Optical sensing of HCl with phenol red doped sol-gels

Energy Technology Data Exchange (ETDEWEB)

Wang Enju [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States)]. E-mail: wange@stjohns.edu; Chow, Kwok-Fan [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Wang Wenqun [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Wong, Crystal [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Yee, Cynthia [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Persad, Alvin [Department of Chemistry, St. John' s University, 8000 Utopia Parkway, Jamaica, NY 11439 (United States); Mann, Jonathan [Department of Chemistry, Princeton University, Princeton, NJ 08540 (United States); Bocarsly, Andrew [Department of Chemistry, Princeton University, Princeton, NJ 08540 (United States)

2005-04-08

A dye doped sol-gel for the sensing of hydrochloric acid in solution and/or gaseous phase is described. The sol-gel is obtained by acidic hydrolysis of tetraethoxysilane (TEOS) and phenyltriethoxysilane (Ph-TriEOS) in the presence of phenol red (PR) and further spin-coating onto glass slides. The sensitive response is based on an increase of the absorption band at 510 nm of phenol red entrapped in the sol-gel casting when exposed to HCl solution or gas, due to protonation of the dye. The detection limit of the sol-gel response to moisturized gaseous HCl is below 12 ppm, and its response to HCl in solution falls in the range of 0.01-6 M. The sol-gel coating has a response time of less than 40 s in steady-state, and life-time of more than a year. Weak acids such as acetic acid, benzoic acid, salicylate acid, citrate acid, and carbonic acid do not interfere the response. The responses in acid solutions are completely reversible. In the gaseous phase, response of HCl appears to be moisture sensitive.

Preparation of highly oriented Al:ZnO and Cu/Al:ZnO thin films by sol-gel method and their characterization

Energy Technology Data Exchange (ETDEWEB)

Vijayaprasath, G.; Murugan, R. [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Mahalingam, T. [Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749 (Korea, Republic of); Hayakawa, Y. [Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011 (Japan); Ravi, G., E-mail: gravicrc@gmail.com [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India)

2015-11-15

Highly oriented thin films of Al doped ZnO (Al:ZnO) and Cu co-doped Al:ZnO (Cu/Al:ZnO) thin films were successfully deposited by sol–gel spin coating on glass substrates. The deposited films were characterized using X-ray diffraction analysis and found to exhibit hexagonal wurtzite structure with c-axis orientation. SEM images revealed that hexagonal rod shaped morphologies were grown perpendicular to the substrate surface due to repeated deposition process. High transmittance values were observed for pure ZnO compared to Al:ZnO and Cu/Al:ZnO thin films. The band gap widening is caused by the increase of carrier concentration, which is believed to be due to Burstein-Moss effect due to Al and Cu doping. PL spectra of Cu/Al:ZnO thin films indicate that the UV emission peaks slightly shifted towards lower energy side. XPS study was carried out for Zn{sub 0.80}Al{sub 0.10}Cu{sub 0.10}O thin films to analyze the binding energy of Al, Cu, Zn and O. Magnetic measurement studies exhibited ferromagnetic behavior at room temperature, which may be due to the increase in copper concentration in the doped films. The ferromagnetic behavior can be understood from the exchange coupling between localized ‘d’ spin of Cu ion mediated by free delocalized carriers. - Highlights: • High quality of Al:ZnO and Cu co-doped Al:ZnO thin films were fabricated by sol–gel method. • The XRD analyses revealed that the deposited thin films have hexagonal wurtzite structure. • XPS was carried out for Zn{sub 0.80}Al{sub 0.10}Cu{sub 0.10}O films to analyze the binding energy of Al, Cu, Zn and O. • SEM studies were made for Al:ZnO and Cu/Al:ZnO thin films. • RTFM was observed in Cu co-doped Al:ZnO thin films.

Impact of an integrated core/SOL description on the R and B T optimization of tokamak fusion reactors

Science.gov (United States)

Siccinio, M.; Fable, E.; Angioni, C.; Saarelma, S.; Scarabosio, A.; Zohm, H.

2018-01-01

An updated and improved version of the 0D divertor and scrape-off layer (SOL) model published in Siccinio et al (2016 Plasma Phys. Control. Fusion 58 125011) was coupled with the 1.5D transport code ASTRA (Pereverzev 1991 IPP Report 5/42, Pereverzev and Yushmanov 2002 IPP Report 5/98 and Fable et al 2013 Plasma Phys. Control. Fusion 55 124028). The resulting numerical tool was employed for various scans in the major radius R and in the toroidal magnetic field B T—for different safety factors q, allowable loop voltages V loop and H factors—in order to identify the most convenient choices for an electricity producing tokamak. Such a scenario analysis was carried out evaluating self-consistently, and simultaneously, the core profile and transport effects, which significantly impact on the fusion power outcome, and the divertor heat loads, which represent one of the most critical issues in view of the realization of fusion power plants (Zohm et al 2013 Nucl. Fusion 53 073019 and Wenninger et al 2017 Nucl. Fusion 57 046002). The main result is that, when divertor limits are enforced, the curves at constant electrical power output are closed on themselves in the R-BT plane, and a maximum achievable power exists—i.e. no benefits would be obtained from a further increase in R and B T once the optimum is reached. This result appears as an intrinsic physical limit for all those devices where a radiative SOL is needed to deal with the power exhaust, and where a lower limit on the power crossing the separatrix (e.g. because of the L-H transition) is present.

Mécanique des sols et des roches

CERN Document Server

Vullier, Laurent; Zhao, Jian

2016-01-01

La mécanique des sols et la mécanique des roches sont des disciplines généralement traitées séparément dans la littérature. Pour la première fois, un traité réunit ces deux spécialités, en intégrant également les connaissances en lien avec les écoulements souterrains et les transferts thermiques. A la fois théorique et pratique, cet ouvrage propose tout d'abord une description détaillée de la nature et de la composition des sols et des roches, puis s'attache à la modélisation de problèmes aux conditions limites et présente les essais permettant de caractériser les sols et les roches, tant d'un point de vue mécanique qu'hydraulique et thermique. La problématique des sols non saturés et des écoulements multiphasiques est également abordée. Une attention particulière est portée aux lois de comportement mécanique et à la détermination de leurs paramètres par des essais in situ et en laboratoire, et l'ouvrage offre également une présentation détaillée des systèmes de classi...

Fabrication of indium tin oxide (ITO) thin film with pre-treated sol coating

International Nuclear Information System (INIS)

Hong, Sung-Jei; Han, Jeong-In

2004-01-01

A new pre-treated sol-coating method to fabricate an indium tin oxide (ITO) thin film is introduced in this paper. The pre-treatment sol-coating method is to form a seed layer on the substrate before spin coating of ITO sol. The pre-treatment was carried out at room temperature in order not to damage the substrate during the pre-treatment. It is effective to enhance the formation of the ITO sol film on the substrate, owing to the seed layer. The seed layer consists of ultrafine grains, which are observed at the pre-treated substrate. For the optimal pre-treatment condition, we used pre-treatment times of 24, 48, 72, and 96 hours to observe the effect on the characteristics of ITO sol film. As a result, the lowest resistance could be achieved with a pre-treatment time of 72 hours. The optical transmittance of the ITO sol film with the pre-treatment time of 72 hours exceeded 80 % at a wavelength of 400 nm. So, an ITO sol film with good electrical and optical properties could be fabricated by using the pretreatment sol coating.

Analyses of laser and furnace treated sol-gel coatings

NARCIS (Netherlands)

De Hosson, JT; De Haas, M; Sudarshan, TS; Jeandin, M; Khor, KA

1998-01-01

Here we explore a new method that allows thin films to be made with almost any composition and degree of porosity by means of a combination of sol-gel and laser technology. Results are presented for furnace and laser treated TEOTI-(tetraethylorthotitanate as sol precursor) coated silicon samples.

La gran vida al aire libre PSA (:30) (The Great Outdoors)

Centers for Disease Control (CDC) Podcasts

2016-05-31

Un hombre y una mujer se están alistando para irse a una caminata. La mujer le recuerda al hombre que se proteja del sol.  Created: 5/31/2016 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 5/31/2016.

Bactericidal micron-thin sol-gel films prevent pin tract and periprosthetic infection.

Science.gov (United States)

Qu, Haibo; Knabe, Christine; Burke, Megan; Radin, Shula; Garino, Jonathan; Schaer, Thomas; Ducheyne, Paul

2014-08-01

Orthopedic injuries constitute the majority of wounds sustained by U.S. soldiers in recent conflicts. The risk of infection is considerable with fracture fixation devices. In this pilot study, we examined the use of unique bactericidal micron-thin sol-gel films on fracture fixation devices and their ability to prevent and eradicate infections. External fixation was studied with micron-thin sol-gel coated percutaneous pins releasing triclosan and inserted medially into rabbit tibiae. A total of 11 rabbits received percutaneous pins that were either uncoated or sol-gel/triclosan coated. Internal fracture fixation was also studied using sol-gel coated intramedullary (IM) nails releasing vancomycin in the intramedullary tibiae. Six sheep received IM nails that were coated with a sol-gel film that either contained vancomycin or did not contain vancomycin. All animals were challenged with Staphylococcus aureus around the implant. Animals were euthanized at 1 month postoperative. Rabbits receiving triclosan/sol-gel coated percutaneous pins did not show signs of infection. Uncoated percutaneous pins had a significantly higher infection rate. In the sheep study, there were no radiographic signs of osteomyelitis with vancomycin/sol-gel coated IM nails, in contrast to the observations in the control cohort. Hence, the nanostructured sol-gel controlled release technology offers the promise of a reliable and continuous delivery system of bactericidals from orthopedic devices to prevent and treat infection. Reprint & Copyright © 2014 Association of Military Surgeons of the U.S.

Ionogel Electrolytes through Sol-Gel Processing

Science.gov (United States)

Horowitz, Ariel I.

Electrical energy needs have intensified due to the ubiquity of personal electronics, the decarbonization of energy services through electrification, and the use of intermittent renewable energy sources. Despite developments in mechanical and thermal methods, electrochemical technologies are the most convenient and effective means of storing electrical energy. These technologies include both electrochemical cells, commonly called batteries, and electrochemical double-layer capacitors, or "supercapacitors", which store energy electrostatically. Both device types require an ion-conducting electrolyte. Current devices use solutions of complex salts in organic solvents, leading to both toxicity and flammability concerns. These drawbacks can be avoided by replacing conventional electrolytes with room-temperature molten salts, known as ionic liquids (ILs). ILs are non-volatile, non-flammable, and offer high conductivity and good electrochemical stability. Device mass can be reduced by combining ILs with a solid scaffold material to form an "ionogel," further improving performance metrics. In this work, sol-gel chemistry is explored as a means of forming ionogel electrolytes. Sol-gel chemistry is a solution-based, industrially-relevant, well-studied technique by which solids such as silica can be formed in situ. Previous works used a simple acid-catalyzed sol-gel reaction to create brittle, glassy ionogels. Here, both the range of products that can be accomplished through sol-gel processing and the understanding of interactions between ILs and the sol-gel reaction network are greatly expanded. This work introduces novel ionogel materials, including soft and compliant silica-supported ionogels and PDMS-supported ionogels. The impacts of the reactive formulation, IL identity, and casting time are detailed. It is demonstrated that variations in formulation can lead to rapid gelation and open pore structures in the silica scaffold or slow gelation and more dense silica

Sol-gel bonding of silicon wafers

International Nuclear Information System (INIS)

Barbe, C.J.; Cassidy, D.J.; Triani, G.; Latella, B.A.; Mitchell, D.R.G.; Finnie, K.S.; Bartlett, J.R.; Woolfrey, J.L.; Collins, G.A.

2005-01-01

Low temperature bonding of silicon wafers was achieved using sol-gel technology. The initial sol-gel chemistry of the coating solution was found to influence the mechanical properties of the resulting bonds. More precisely, the influence of parameters such as the alkoxide concentration, water-to-alkoxide molar ratio, pH, and solution aging on the final bond morphologies and interfacial fracture energy was studied. The thickness and density of the sol-gel coating were characterised using ellipsometry. The corresponding bonded specimens were investigated using attenuated total reflectance Fourier transformed infrared spectroscopy to monitor their chemical composition, infrared imaging to control bond integrity, and cross-sectional transmission electron microscopy to study their microstructure. Their interfacial fracture energy was measured using microindentation. An optimum water-to-alkoxide molar ratio of 10 and hydrolysis water at pH = 2 were found. Such conditions led to relatively dense films (> 90%), resulting in bonds with a fracture energy of 3.5 J/m 2 , significantly higher than those obtained using classical hydrophilic bonding (typically 1.5-2.5 J/m 2 ). Ageing of the coating solution was found to decrease the bond strength

Opportunity's View After Long Drive on Sol 1770 (Vertical)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 104 meters (341 feet) on the 1,770th Martian day, or sol, of Opportunity's surface mission (January 15, 2009). This view is presented as a vertical projection with geometric seam correction. North is at the top. Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). Prior to the Sol 1770 drive, Opportunity had driven less than a meter since Sol 1713 (November 17, 2008), while it used the tools on its robotic arm first to examine a meteorite called 'Santorini' during weeks of restricted communication while the sun was nearly in line between Mars and Earth, then to examine bedrock and soil targets near Santorini. The rover's position after the Sol 1770 drive was about 1.1 kilometer (two-thirds of a mile) south southwest of Victoria Crater. Cumulative odometry was 13.72 kilometers (8.53 miles) since landing in January 2004, including 1.94 kilometers (1.21 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

Opportunity's View After Long Drive on Sol 1770 (Polar)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 104 meters (341 feet) on the 1,770th Martian day, or sol, of Opportunity's surface mission (January 15, 2009). This view is presented as a polar projection with geometric seam correction. North is at the top. Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). Prior to the Sol 1770 drive, Opportunity had driven less than a meter since Sol 1713 (November 17, 2008), while it used the tools on its robotic arm first to examine a meteorite called 'Santorini' during weeks of restricted communication while the sun was nearly in line between Mars and Earth, then to examine bedrock and soil targets near Santorini. The rover's position after the Sol 1770 drive was about 1.1 kilometer (two-thirds of a mile) south southwest of Victoria Crater. Cumulative odometry was 13.72 kilometers (8.53 miles) since landing in January 2004, including 1.94 kilometers (1.21 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008).

Human SolCD39 Inhibits Injury-induced Development of Neointimal Hyperplasia

Science.gov (United States)

Drosopoulos, Joan H. F.; Kraemer, Rosemary; Shen, Hao; Upmacis, Rita K.; Marcus, Aaron J.; Musi, Elgilda

2010-01-01

SUMMARY Blood platelets provide the initial response to vascular endothelial injury, becoming activated as they adhere to the injured site. Activated platelets recruit leukocytes, and initiate proliferation and migration of vascular smooth muscle cells (SMC) within the injured vessel wall, leading to development of neointimal hyperplasia. Endothelial CD39/NTPDase1 and recombinant solCD39 rapidly metabolize nucleotides, including stimulatory ADP released from activated platelets, thereby suppressing additional platelet reactivity. Using a murine model of vascular endothelial injury, we investigated whether circulating human solCD39 could reduce platelet activation and accumulation, thus abating leukocyte infiltration and neointimal formation following vascular damage. Intraperitoneally-administered solCD39 ADPase activity in plasma peaked 1 hr post-injection, with an elimination half-life of 43 hr. Accordingly, mice were administered solCD39 or saline 1 hr prior to vessel injury, then either sacrificed 24 hr post-injury or treated with solCD39 or saline (3X weekly) for an additional 18 days. 24 hr post-injury, solCD39-treated mice displayed a reduction in platelet activation and recruitment, P-selectin expression, and leukocyte accumulation in the arterial lumen. Furthermore, repeated administration of solCD39 modulated the late stage of vascular injury by suppressing leukocyte deposition, macrophage infiltration and SMC proliferation/migration, resulting in abrogation of neointimal thickening. In contrast, injured femoral arteries of saline-injected mice exhibited massive platelet thrombus formation, marked P-selectin expression, and leukocyte infiltration. Pronounced neointimal growth with macrophage and SMC accretion was also observed (intimal-to-medial area ratio 1.56±0.34 at 19 days). Thus, systemic administration of solCD39 profoundly affects injury-induced cellular responses, minimizing platelet deposition and leukocyte recruitment, and suppressing

Permanent Habitats in Earth-Sol/Mars-Sol Orbit Positions

Science.gov (United States)

Greenspon, J.

Project Outpost is a manned Earth-Sol/Mars-Sol platform that enables permanent occupation in deep space. In order to develop the program elements for this complex mission, Project Outpost will rely primarily on existing/nearterm technology and hardware for the construction of its components. For the purposes of this study, four mission requirements are considered: 1. Outpost - Man's 1st purpose-produced effort of space engineering, in which astructure is developed/constructed in an environment completely alien to currentpractices for EVA guidelines. 2. Newton - a concept study developed at StarGate Research, for the development ofa modified Hohmann personnel orbital transport operating between Earth andMars. Newton would serve as the primary crew delivery apparatus throughrepeatable transfer scheduling for all Earth-Lpoint-Mars activities. Thispermanent "transit system" would establish the foundations for Solar systemcolonization. 3. Cruis - a concept study developed at StarGate Research, for the development of amodified Hohmann cargo orbital transport operating between Earth and Mars.Cruis would serve as the primary equipment delivery apparatus throughrepeatable transfer scheduling for all Earth-Lpoint-Mars activities. Thispermanent "transit system" would establish the foundations for Solar systemcolonization, and 4. Ares/Diana - a more conventional space platform configuration for Lunar andMars orbit is included as a construction baseline. The operations of these assetsare supported, and used for the support, of the outpost. Outpost would be constructed over a 27-year period of launch opportunities into Earth-Sol or Mars-Sol Lagrange orbit (E-S/M-S L1, 4 or 5). The outpost consists of an operations core with a self-contained power generation ability, a docking and maintenance structure, a Scientific Research complex and a Habitation Section. After achieving initial activation, the core will provide the support and energy required to operate the outpost in a 365

Opportunity's Surroundings on Sol 1818 (Vertical)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends. This view is presented as a vertical projection with geometric seam correction. North is at the top. The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view. The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

Opportunity's Surroundings on Sol 1818 (Polar)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends. This view is presented as a polar projection with geometric seam correction. North is at the top. The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view. The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

Neutron detector using sol-gel absorber

Science.gov (United States)

Hiller, John M.; Wallace, Steven A.; Dai, Sheng

1999-01-01

An neutron detector composed of fissionable material having ions of lithium, uranium, thorium, plutonium, or neptunium, contained within a glass film fabricated using a sol-gel method combined with a particle detector is disclosed. When the glass film is bombarded with neutrons, the fissionable material emits fission particles and electrons. Prompt emitting activated elements yielding a high energy electron contained within a sol-gel glass film in combination with a particle detector is also disclosed. The emissions resulting from neutron bombardment can then be detected using standard UV and particle detection methods well known in the art, such as microchannel plates, channeltrons, and silicon avalanche photodiodes.

Integrated simulation of ELM energy loss determined by pedestal MHD and SOL transport

International Nuclear Information System (INIS)

Hayashi, N.; Takizuka, T.; Ozeki, T.; Aiba, N.; Oyama, N.

2007-01-01

An integrated simulation code TOPICS-IB based on a transport code with a stability code for the peeling-ballooning modes and a scrape-off-layer (SOL) model has been developed to clarify self-consistent effects of edge localized modes (ELMs) and the SOL on the plasma performance. Experimentally observed collisionality dependence of the ELM energy loss is found to be caused by both the edge bootstrap current and the SOL transport. The bootstrap current decreases with an increase in collisionality and intensifies the magnetic shear at the pedestal region. The increase in the magnetic shear reduces the width of eigenfunctions of unstable modes, which results in the reduction of both the area of the ELM enhanced transport and the ELM enhanced transport near the separatrix. On the other hand, when an ELM crash occurs, the energy flows into the SOL and the SOL temperature rapidly increases. The increase in the SOL temperature lowers the ELM energy loss due to the flattening of the radial edge gradient. The parallel electron heat conduction determines how the SOL temperature increases. For higher collisionality, the conduction becomes lower and the SOL electron temperature increases more. By the above two mechanisms, the ELM energy loss decreases with increasing collisionality

Mesure de la vitesse d'infiltration des eaux dans le sol : Cas des sols ...

African Journals Online (AJOL)

SARAH

30 avr. 2016 ... Pour ceux, il est nécessaire d'opter pour une agriculture moderne ... à une telle agriculture. Mots clés : mesure, vitesse, infiltration, sols, pollutions, eau, Niari, Congo .... une porosité tubulaire d'origine biologique. Toutes ces.

Evolution of heterogeneity accompanying sol-gel transitions in a supramolecular hydrogel.

Science.gov (United States)

Matsumoto, Yuji; Shundo, Atsuomi; Ohno, Masashi; Tsuruzoe, Nobutomo; Goto, Masahiro; Tanaka, Keiji

2017-10-18

When a peptide amphiphile is dispersed in water, it self-assembles into a fibrous network, leading to a supramolecular hydrogel. When the gel is physically disrupted by shaking, it transforms into a sol state. After aging at room temperature for a while, it spontaneously returns to the gel state, called sol-gel transition. However, repeating the sol-gel transition often causes a change in the rheological properties of the gel. To gain a better understanding of the sol-gel transition and its reversibility, we herein examined the thermal motion of probe particles at different locations in a supramolecular hydrogel. The sol obtained by shaking the gel was heterogeneous in terms of the rheological properties and the extent decreased with increasing aging time. This time course of heterogeneity, or homogeneity, which corresponded to the sol-to-gel transition, was observed for the 1st cycle. However, this was not the case for the 2nd and 3rd cycles; the heterogeneity was preserved even after aging. Fourier-transform infrared spectroscopy, small-angle X-ray scattering, and atomic force and confocal laser scanning microscopies revealed that, although the molecular aggregation states of amphiphiles both in the gel and sol remained unchanged with the cycles, the fibril density diversified to high and low density regions even after aging. The tracking of particles with different sizes indicated that the partial mesh size in the high density region and the characteristic length scale of the density fluctuation were smaller than 50 nm and 6 μm, respectively.

Entrapment of subtilisin in ceramic sol-gel coating for antifouling applications.

Science.gov (United States)

Regina, Viduthalai Rasheedkhan; Søhoel, Helmer; Lokanathan, Arcot Raghupathi; Bischoff, Claus; Kingshott, Peter; Revsbech, Niels Peter; Meyer, Rikke Louise

2012-11-01

Enzymes with antifouling properties are of great interest in developing nontoxic antifouling coatings. A bottleneck in developing enzyme-based antifouling coatings is to immobilize the enzyme in a suitable coating matrix without compromising its activity and stability. Entrapment of enzymes in ceramics using the sol-gel method is known to have several advantages over other immobilization methods. The sol-gel method can be used to make robust coatings, and the aim of this study was to explore if sol-gel technology can be used to develop robust coatings harboring active enzymes for antifouling applications. We successfully entrapped a protease, subtilisin (Savinase, Novozymes), in a ceramic coating using a sol-gel method. The sol-gel formulation, when coated on a stainless steel surface, adhered strongly and cured at room temperature in less than 8 h. The resultant coating was smoother and less hydrophobic than stainless steel. Changes in the coating's surface structure, thickness and chemistry indicate that the coating undergoes gradual erosion in aqueous medium, which results in release of subtilisin. Subtilisin activity in the coating increased initially, and then gradually decreased. After 9 months, 13% of the initial enzyme activity remained. Compared to stainless steel, the sol-gel-coated surfaces with active subtilisin were able to reduce bacterial attachment of both Gram positive and Gram negative bacteria by 2 orders of magnitude. Together, our results demonstrate that the sol-gel method is a promising coating technology for entrapping active enzymes, presenting an interesting avenue for enzyme-based antifouling solutions.

Collisionality dependent transport in TCV SOL plasmas

DEFF Research Database (Denmark)

Garcia, Odd Erik; Pitts, R.A.; Horacek, J.

2007-01-01

Results are presented from probe measurements in the low field side scrape-off layer (SOL) region of TCV during plasma current scan experiments. It is shown that with decreasing plasma current the radial particle density profile becomes broader and the fluctuation levels and turbulence driven...... radial particle flux increase. In the far SOL the fluctuations exhibit a high degree of statistical similarity and the particle density and flux at the wall radius scale inversely with the plasma current. Together with previous TCV density scan experiments, this indicates that plasma fluctuations...

Opportunity's View After Drive on Sol 1806 (Polar)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 60.86 meters (200 feet) on the 1,806th Martian day, or sol, of Opportunity's surface mission (Feb. 21, 2009). North is at the center; south at both ends. Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). Engineers designed the Sol 1806 drive to be driven backwards as a strategy to redistribute lubricant in the rovers wheels. The right-front wheel had been showing signs of increased friction. The rover's position after the Sol 1806 drive was about 2 kilometer (1.2 miles) south southwest of Victoria Crater. Cumulative odometry was 14.74 kilometers (9.16 miles) since landing in January 2004, including 2.96 kilometers (1.84 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008). This view is presented as a polar projection with geometric seam correction.

Opportunity's View After Drive on Sol 1806 (Vertical)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings just after driving 60.86 meters (200 feet) on the 1,806th Martian day, or sol, of Opportunity's surface mission (Feb. 21, 2009). North is at the center; south at both ends. Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). Engineers designed the Sol 1806 drive to be driven backwards as a strategy to redistribute lubricant in the rovers wheels. The right-front wheel had been showing signs of increased friction. The rover's position after the Sol 1806 drive was about 2 kilometer (1.2 miles) south southwest of Victoria Crater. Cumulative odometry was 14.74 kilometers (9.16 miles) since landing in January 2004, including 2.96 kilometers (1.84 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008). This view is presented as a vertical projection with geometric seam correction.

Sol-gel open tubular ODS columns with reversed electroosmotic flow for capillary electrochromatography.

Science.gov (United States)

Hayes, J D; Malik, A

2001-03-01

Sol-gel chemistry was successfully used for the fabrication of open tubular columns with surface-bonded octadecylsilane (ODS) stationary-phase coating for capillary electrochromatography (OT-CEC). Following column preparations, a series of experiments were performed to investigate the performance of the sol-gel coated ODS columns in OT-CEC. The incorporation of N-octadecyldimethyl[3-(trimethoxysilyl)propyl]ammonium chloride as one of the sol-gel precursors played an important role in the electrochromatographic performance of the prepared columns. This chemical reagent possesses a chromatographically favorable, bonded ODS moiety, in conjunction with three methoxy groups allowing for sol-gel reactivity. In addition, a positively charged nitrogen atom is present in the molecular structure of this reagent and provides a positively charged capillary surface responsible for the reversed electroosmotic flow (EOF) in the columns during CEC operation. Comparative studies involving the EOF within such sol-gel ODS coated and uncoated capillaries were performed using acetonitrile and methanol as the organic modifiers in the mobile phase. The use of a deactivating reagent, phenyldimethylsilane, in the sol-gel solution was evaluated. Efficiency values of over 400,000 theoretical plates per meter were achieved in CEC on a 64 cm x 25 microm i.d. sol-gel ODS open tubular column. Test mixtures of polycyclic aromatic hydrocarbons, benzene derivatives, and aromatic aldehydes and ketones were used to evaluate the CEC performances of both nondeactivated and deactivated open tubular sol-gel columns. The effects of mobile-phase organic modifier contents and pH on EOF in such columns were evaluated. The prepared sol-gel ODS columns are characterized by switchable electroosmotic flow. A pH value of approximately 8.5 was found correspond to the isoelectric point for the prepared sol-gel ODS coatings.

The effect of synthetic method and annealing temperature on metal site preference in Al(1-x)Ga(x)FeO3.

Science.gov (United States)

Walker, James D S; Grosvenor, Andrew P

2013-08-05

Magnetoelectric materials couple both magnetic and electronic properties, making them attractive for use in multifunctional devices. The magnetoelectric AFeO3 compounds (Pna2(1); A = Al, Ga) have received attention as the properties of the system depend on composition as well as the synthetic method used. Al(1-x)Ga(x)FeO3. (0 ≤ x ≤ 1) was synthesized by the sol-gel and coprecipitation methods and studied by X-ray absorption near-edge spectroscopy (XANES). Al L(2,3-), Ga K-, and Fe K-edge XANES spectra were collected to examine how the average metal coordination number (CN) changes with the synthetic method. Al and Fe were found to prefer octahedral sites, while Ga prefers the tetrahedral site. It was found that composition played a larger role in determining site occupancies than synthetic method. Samples made by the sol-gel or ceramic methods (reported previously; Walker, J. D. S.; Grosvenor, A. P. J. Solid State Chem. 2013, 197, 147-153) showed smaller spectral changes than samples made via the coprecipitation method. This is attributed to greater ion mobility in samples synthesized via coprecipitation as the reactants do not have a long-range polymeric or oxide network during synthesis like samples synthesized via the sol-gel or ceramic method. Increasing annealing temperature increases the average coordination number of Al, and to a lesser extent Ga, while the average coordination number of Fe decreases. This study indicates that greater disorder is observed when the Al(1-x)Ga(x)FeO3. compounds have high Al content, and when annealed at higher temperatures.

Análisis del perfil de compuestos volátiles del mango (mangifera indica l. var. tommy atkins) tratado por métodos combinados

OpenAIRE

Moreno, Angélica; León, David F.; Giraldo, Germán A.; Ríos, Eunice

2010-01-01

Se evaluó el perfil de compuestos volátiles del mango (Mangifera indica L. Var. Tommy Atkins) al ser tratado con la combinación de los métodos de deshidratación osmótica con o sin pulso de vacío (DOPV y DO) y con secado por aire caliente o con vacío (SAC y VAC). El tiempo utilizado en la cinética del proceso de DO fue de 42 horas y la DOPV de 30 horas; en los procesos de secado, el SAC se realizó durante 24 horas y el VAC requirió 40 horas. En el perfil de compuestos volátiles del mango fresc...

ANÁLISIS DEL PERFIL DE COMPUESTOS VOLÁTILES DEL MANGO (Mangifera indica L. Var. Tommy Atkins) TRATADO POR MÉTODOS COMBINADOS

OpenAIRE

Angélica Moreno; David F. León; Germán A. Giraldo; Eunice Ríos

2010-01-01

Se evaluó el perfil de compuestos volátiles del mango (Mangifera indica L. Var. Tommy Atkins) al ser tratado con la combinación de los métodos de deshidratación osmótica con o sin pulso de vacío (DOPV y DO) y con secado por aire caliente o con vacío (SAC y VAC). El tiempo utilizado en la cinética del proceso de DO fue de 42 horas y la DOPV de 30 horas; en los procesos de secado, el SAC se realizó durante 24 horas y el VAC requirió 40 horas. En el perfil de compuestos volátiles del mango fresc...

Electrical characterization of γ-Al2O3 thin film parallel plate capacitive sensor for trace moisture detection

Science.gov (United States)

Kumar, Lokesh; Kumar, Shailesh; Khan, S. A.; Islam, Tariqul

2012-10-01

A moisture sensor was fabricated based on porous thin film of γ-Al2O3 formed between the parallel gold electrodes. The sensor works on capacitive technique. The sensing film was fabricated by dipcoating of aluminium hydroxide sol solution obtained from the sol-gel method. The porous structure of the film of γ-Al2O3 phase was obtained by sintering the film at 450 °C for 1 h. The electrical parameters of the sensor have been determined by Agilent 4294A impedance analyzer. The sensor so obtained is found to be sensitive in moisture range 100-600 ppmV. The response time of the sensor in ppmV range moisture is very low ~ 24 s and recovery time is ~ 37 s.

The use of gypsum mining by-product and lime on the engineering properties of compressed earth blocks

Directory of Open Access Journals (Sweden)

Eliana Rocío Jaramillo-Pérez

2014-01-01

Full Text Available Las desventajas de los bloques de tierra comprimida son sus baj as propiedades mecánicas y resistencia al daño al agua. Por lo tanto, su uso es vulnerable al deterioro y requiere cuidado y mantenimien to, dependiendo del grado de estabilización y compactación del suelo arcilloso. Residuos de minería del yeso y cal se utilizaron com o estabilizantes para mejorar las propiedades de estos material es de construcción. Resistencia a compresión y flexión, ablandamiento en agua, retracción por secado y peso unitario se determinaron . La resistencia aumento con la adición de residuo de minería. La re sistencia al ablandamiento en agua fue mayor con 25% de residuo de minería. La contracción por secado disminuyo con el aumento del contenido de residuo de minería. El peso unitario seco no esta ba en los estándares recomendados. Los resultados mostraron que los resid uos de minería del yeso pueden utilizarse como materiales alter nativos en la estabilización de bloques de tierra comprimida.

SOL: A Library for Scalable Online Learning Algorithms

OpenAIRE

Wu, Yue; Hoi, Steven C. H.; Liu, Chenghao; Lu, Jing; Sahoo, Doyen; Yu, Nenghai

2016-01-01

SOL is an open-source library for scalable online learning algorithms, and is particularly suitable for learning with high-dimensional data. The library provides a family of regular and sparse online learning algorithms for large-scale binary and multi-class classification tasks with high efficiency, scalability, portability, and extensibility. SOL was implemented in C++, and provided with a collection of easy-to-use command-line tools, python wrappers and library calls for users and develope...

Spirit Near 'Stapledon' on Sol 1802

Science.gov (United States)

2009-01-01

NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. South is at the center; north is at both ends. Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches). Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica. The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season. This view is presented as a cylindrical projection with geometric seam correction.

Overview Of 100 Sols Of Chemcam Operations At Gale Crater

Science.gov (United States)

Maurice, Sylvestre; Wiens, Roger; MSL Science Team

2013-04-01

The Curiosity rover carries the ChemCam instrument suite, a Laser-Induced Breakdown Spectroscopy (LIBS) instrument that can analyze the chemical composition of geological samples at distances up to 7 meters from the rover, and a high resolution camera for context imaging (RMI). In the first 100 sols after landing, ChemCam performed 343 single point measurements on approximately 50 different rocks or soil areas, for over 12,000 laser shots. Each time at least two RMI images are acquired before and after the laser shots to visualize the area of investigation and the geological context. LIBS lines are identified using primarily a martian dedicated database; to date, ChemCam has detected unambiguously major elements (Si, Al, Fe, Mg, Ca, Na, K, O), minor/trace elements of interest (Li, Cr, Mn, Rb, Sr, Ba, Ti, S, C, H). These observations allow a qualitative/quantitative assessment of the presence of dust (first few shots), the sample surface composition and chemical heterogeneity with depth. Several techniques have been developed to analyze ChemCam's data: (1) Univariate analysis refers to peak height studies of well-chosen LIBS lines and a training dataset to build calibration curves. Peak ratios K/Si, Na/Si, Al/Si, Fe+Mg/Si, or Mg/Mg+Fe have been calculated from the onboard calibration targets. The technique also applies to minor and trace elements which yield low intensity emission lines, such as Lin, Rb, H, C. (2) Multivariate methods give better results in terms of elemental composition, since they examine simultaneously and statistically several peaks of the same elements. A Partial Least Squares (PLS) regression algorithm is used for rapid major-element abundance determination. (3) Composition trends, clusters and end-members can also be identified using component analysis methods. Independent Component Analysis (ICA) identifies components that are directly related to Chemical elements: Al, Ca, Fe, H, K, Mg, Na, O, Si, Ti, but also mixture like a "soil" component

Core-SOL modelling of neon seeded JET discharges with the ITER-like wall

Energy Technology Data Exchange (ETDEWEB)

Telesca, G. [Department of Applied Physics, Ghent University (Belgium); EUROfusion Consortium, JET, Culham Science Centre, Abingdon (United Kingdom); Ivanova-Stanik, I.; Zagoerski, R.; Czarnecka, A. [Institute of Plasma Physics and Laser Microfusion, Warsaw (Poland); EUROfusion Consortium, JET, Culham Science Centre, Abingdon (United Kingdom); Brezinsek, S.; Huber, A.; Wiesen, S. [Forschungszentrum Juelich GmbH, Institut fuer Klima- und Energieforschung-Plasmaphysik, Juelich (Germany); EUROfusion Consortium, JET, Culham Science Centre, Abingdon (United Kingdom); Drewelow, P. [Max-Planck-Institut fuer Plasmaphysik, Greifswald (Germany); EUROfusion Consortium, JET, Culham Science Centre, Abingdon (United Kingdom); Giroud, C. [CCFE Culham, Abingdon (United Kingdom); EUROfusion Consortium, JET, Culham Science Centre, Abingdon (United Kingdom); Collaboration: JET EFDA contributors

2016-08-15

Five ELMy H-mode Ne seeded JET pulses have been simulated with the self-consistent core-SOL model COREDIV. In this five pulse series only the Ne seeding rate was changed shot by shot, allowing a thorough study of the effect of Ne seeding on the total radiated power and of its distribution between core and SOL tobe made. The increase in the simulations of the Ne seeding rate level above that achieved in experiments shows saturation of the total radiated power at a relatively low radiated-heating power ratio (f{sub rad} = 0.60) and a further increase of the ratio of SOL to core radiation, in agreement with the reduction of W release at high Ne seeding level. In spite of the uncertainties caused by the simplified SOL model of COREDIV (neutral model, absence of ELMs and slab model for the SOL), the increase of the perpendicular transport in the SOL with increasing Ne seeding rate, which allows to reproduce numerically the experimental distribution core-SOL of the radiated power, appears to be of general applicability. (copyright 2016 The Authors. Contributions to Plasma Physics published by Wiley-VCH Verlag GmbH and Co. KGaA Weinheim. This)

The SOL-2/Neto auxiliary protein modulates the function of AMPA-subtype ionotropic glutamate receptors.

Science.gov (United States)

Wang, Rui; Mellem, Jerry E; Jensen, Michael; Brockie, Penelope J; Walker, Craig S; Hoerndli, Frédéric J; Hauth, Linda; Madsen, David M; Maricq, Andres V

2012-09-06

The neurotransmitter glutamate mediates excitatory synaptic transmission by gating ionotropic glutamate receptors (iGluRs). AMPA receptors (AMPARs), a subtype of iGluR, are strongly implicated in synaptic plasticity, learning, and memory. We previously discovered two classes of AMPAR auxiliary proteins in C. elegans that modify receptor kinetics and thus change synaptic transmission. Here, we have identified another auxiliary protein, SOL-2, a CUB-domain protein that associates with both the related auxiliary subunit SOL-1 and with the GLR-1 AMPAR. In sol-2 mutants, behaviors dependent on glutamatergic transmission are disrupted, GLR-1-mediated currents are diminished, and GLR-1 desensitization and pharmacology are modified. Remarkably, a secreted variant of SOL-1 delivered in trans can rescue sol-1 mutants, and this rescue depends on in cis expression of SOL-2. Finally, we demonstrate that SOL-1 and SOL-2 have an ongoing role in the adult nervous system to control AMPAR-mediated currents. Copyright © 2012 Elsevier Inc. All rights reserved.

Synthesis by sol-gel and characterization of catalysts Ag/Al{sub 2}O{sub 3}- CeO{sub 2} for the elimination of nitric oxide; Sintesis por sol-gel y caracterizacion de catalizadores Ag/Al{sub 2}O{sub 3}- CeO{sub 2} para la eliminacion del oxido nitrico

Energy Technology Data Exchange (ETDEWEB)

Zayas R, M.L

2005-07-01

The environmental pollution is one from the big problems to solve at the present time, because the quality of the alive beings life is affected. For such reason, more clean and economic technologies are required, that it conduces to develop new catalytic alternatives to diminish the nitrogen oxides that due to its chemical processes in the environment contribute considerably in the air pollution. The main objective of the present work, is the preparation and characterization of catalytic materials with base of silver supported in simple and mixed aluminium oxides (Al{sub 2}O{sub 3}) and Cerium oxide (CeO{sub 2}), and its catalytic evaluation that through of the reduction of nitric oxide (NO) using hydrogen (H{sub 2}) as reducer agent. It was synthesized alumina (Al{sub 2}O{sub 3}) and Cerium oxide (CeO{sub 2}) and mixed oxides (Al{sub 2}O{sub 3}- CeO{sub 2}), by the sol-gel method and the cerium oxide (CeO{sub 2}) by precipitation of the cerium nitrate (III) hexa hydrated. The oxides were stabilized thermally at 900 C by 5 hr. The catalysts were prepared by impregnation using silver nitrate (AgNO{sub 3}), the nominal concentration of Ag was of 5% in weight. The catalysts were reduced at 400 C by 2 hr, in hydrogen flow of 60 cc/min. The characterization of the catalytic materials was carried out through different techniques as: nitrogen adsorption to determine the surface area BET, scanning electron microscopy (SEM) to observe the final morphology of the catalysts, X-ray diffraction (XRD) to identify the crystalline phases of the catalytic materials, Infrared spectroscopy (DRIFT) to know the structural characterization of the catalysts, reduction to programmed temperature (TPR) to evidence the interaction metal-support. The catalytic properties of the catalysts were evaluated in the model reaction NO + H{sub 2}, to determine the activity and selectivity. The results indicate that the preparation technique, the precursors and the thermal treatments that underwent

Mechanical compatibility of sol-gel annealing with titanium for orthopaedic prostheses.

Science.gov (United States)

Greer, Andrew I M; Lim, Teoh S; Brydone, Alistair S; Gadegaard, Nikolaj

2016-01-01

Sol-gel processing is an attractive method for large-scale surface coating due to its facile and inexpensive preparation, even with the inclusion of precision nanotopographies. These are desirable traits for metal orthopaedic prostheses where ceramic coatings are known to be osteoinductive and the effects may be amplified through nanotexturing. However there are a few concerns associated with the application of sol-gel technology to orthopaedics. Primarily, the annealing stage required to transform the sol-gel into a ceramic may compromise the physical integrity of the underlying metal. Secondly, loose particles on medical implants can be carcinogenic and cause inflammation so the coating needs to be strongly bonded to the implant. These concerns are addressed in this paper. Titanium, the dominant material for orthopaedics at present, is examined before and after sol-gel processing for changes in hardness and flexural modulus. Wear resistance, bending and pull tests are also performed to evaluate the ceramic coating. The findings suggest that sol-gel coatings will be compatible with titanium implants for an optimum temperature of 500 °C.

Characterization of the allergen Sol gem 2 from the fire ant venom, Solenopsis geminata

Directory of Open Access Journals (Sweden)

S Sukprasert

2012-01-01

Full Text Available Sol i 2 is a potent allergen in Solenopsis invicta venom, and most humans exhibit reactivity to it. The Sol gem 2 allergen found in the venom of the Thai tropical fire ant Solenopsis geminata was analysed in the present study. The protein was present in higher amounts than other proteins, as determined by SDS-PAGE, and presumably has allergenic properties similar to those of Sol i 2. Sol gem 2 molecular weight is 28 and 15 kDa, respectively, under non-reducing and reducing conditions, indicating that its native form is a dimer. LC-MS/MS analysis confirmed its similarity to Sol i 2. The mono/dimeric form of Sol gem 2 was determined to be relevant by proteomic approach and immunoblotting. An anti-Sol gem 2 antibody was produced in mice, with a titer greater than 1:800 according to the Western blotting analysis. The Sol gem 2-neutralising activity of this antibody was determined in crickets. The paralytic dose 50 (PD50 of crude S. geminata venom was elevated from 0.18 mg/g of body weight to more than 0.90 mg/g of body weight after preincubation with antibody at a ratio of 1:1. These results suggest that Sol gem 2 plays an important role in mediating the effects of the piperidine derivatives in the venom.

Opportunity's Surroundings on Sol 1798 (Polar)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top. This view is presented as a polar projection with geometric seam correction. The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

Opportunity's Surroundings on Sol 1798 (Vertical)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top. This view is presented as a vertical projection with geometric seam correction. The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock.

Structure of hybrid organic-inorganic sols for the preparation of hydrothermally stable membranes

Energy Technology Data Exchange (ETDEWEB)

Castricum, H.L.; Sah, A; Blank, D.H.A.; Ten Elshof, J.E. [Inorganic Materials Science, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Geenevasen, J.A.J. [Van ' t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam (Netherlands); Kreiter, R.; Vente, J.F. [ECN Energy Efficiency in the Industry, Petten (Netherlands)

2008-06-15

A procedure for the preparation of hybrid sols for the synthesis of organic-inorganic microporous materials and thin film membranes is reported. We describe silane reactivity and sol structure for acid-catalysed colloidal sols from mixtures of either tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES), or bis(triethoxysilyl)ethane (BTESE) and MTES. Early-stage hydrolysis and condensation rates of the individual silane precursors were followed with 29Si liquid NMR and structural characteristics of more developed sols were studied with Dynamic Light Scattering. Condensation was found to proceed at more or less similar rates for the different precursors. Homogeneously mixed hybrid colloids can therefore be formed from precursor mixtures. The conditions of preparation under which clear sols with low viscosity could be formed from BTESE/MTES were determined. These sols were synthesised at moderate water/silane and acid/silane ratios and could be applied for the coating of defect-free microporous membranes for molecular separations under hydrothermal conditions.

One-step sol-gel imprint lithography for guided-mode resonance structures.

Science.gov (United States)

Huang, Yin; Liu, Longju; Johnson, Michael; C Hillier, Andrew; Lu, Meng

2016-03-04

Guided-mode resonance (GMR) structures consisting of sub-wavelength periodic gratings are capable of producing narrow-linewidth optical resonances. This paper describes a sol-gel-based imprint lithography method for the fabrication of submicron 1D and 2D GMR structures. This method utilizes a patterned polydimethylsiloxane (PDMS) mold to fabricate the grating coupler and waveguide for a GMR device using a sol-gel thin film in a single step. An organic-inorganic hybrid sol-gel film was selected as the imprint material because of its relatively high refractive index. The optical responses of several sol-gel GMR devices were characterized, and the experimental results were in good agreement with the results of electromagnetic simulations. The influence of processing parameters was investigated in order to determine how finely the spectral response and resonant wavelength of the GMR devices could be tuned. As an example potential application, refractometric sensing experiments were performed using a 1D sol-gel device. The results demonstrated a refractive index sensitivity of 50 nm/refractive index unit. This one-step fabrication process offers a simple, rapid, and low-cost means of fabricating GMR structures. We anticipate that this method can be valuable in the development of various GMR-based devices as it can readily enable the fabrication of complex shapes and allow the doping of optically active materials into sol-gel thin film.

Sol-Gel Production; Proceedings of the First International Conference on Application and Commercialization of Sol-Gel Processing Held in Saarbruecken, Germany on 24-25 May 1993

National Research Council Canada - National Science Library

Schmidt, Helmut

1998-01-01

...; Sol-Gel Coatings on Large Glass Substrates for Multilayer Interference Systems; A SiO2-ZrO2 Gel Film doped with Organic Pigments Made by the Sol-Gel Method for Contrast Enhancement of Color Picture Tubes...

Impurity enrichment and radiative enhancement using induced SOL flow in DIII-D

International Nuclear Information System (INIS)

Wade, M.R.; West, W.P.; Wood, R.D.

1998-07-01

Experiments on DIII-D have demonstrated the efficacy of using induced scrap-off-layer (SOL) flow to preferentially enrich impurities in the divertor plasma. This SOL floe is produced through simultaneous deuterium gas injection at the midplane and divertor exhaust. Using this SOL flow, an improvement in enrichment (defined as the ratio of impurity fraction in the divertor to that in the plasma core) has been observed for all impurities in trace-level experiments (i.e., impurity level is non-perturbative), with the degree of improvement increasing with impurity atomic number. In the case of argon, exhaust gas enrichment using modest SOL flow is as high as 17. Using this induced SOL flow technique and argon injection, radiative plasmas have been produced that combine high radiation losses (P rad /P input > 70%), low core fuel dilution (Z eff E > 1.0 τ E,ITER93H )

Laboratory Testing of Silica Sol Grout in Coal Measure Mudstones

Directory of Open Access Journals (Sweden)

Dongjiang Pan

2016-11-01

Full Text Available The effectiveness of silica sol grout on mudstones is reported in this paper. Using X-ray diffraction (XRD, the study investigates how the silica sol grout modifies mudstone mineralogy. Micropore sizes and mechanical properties of the mudstone before and after grouting with four different materials were determined with a surface area/porosity analyser and by uniaxial compression. Tests show that, after grouting, up to 50% of the mesopore volumes can be filled with grout, the dominant pore diameter decreases from 100 nm to 10 nm, and the sealing capacity is increased. Uniaxial compression tests of silica sol grouted samples shows that their elastic modulus is 21%–38% and their uniaxial compressive strength is 16%–54% of the non-grouted samples. Peak strain, however, is greater by 150%–270%. After grouting, the sample failure mode changes from brittle to ductile. This paper provides an experimental test of anti-seepage and strengthening properties of silica sol.

A utilização de materiais obtidos pelo processo de sol-gel na construção de biossensores The utilization of materials obtained by the sol-gel process in biosensors construction

Directory of Open Access Journals (Sweden)

Antonio A. S. Alfaya

2002-09-01

Full Text Available The use of sol-gel materials to develop new biosensors has received great attention due to its characteristics and versatility of sol-gel process. An overview is presented of the state-of-the-art of electrochemical biosensors employing sol-gel materials. Low-temperature, porous sol-gel ceramics represent a new class for the immobilization of biomolecules. The rational design of sol-gel sensing materials, based on the judicious choice of the starting alkoxide, encapsulated reagents, and preparation conditions, allows tailoring of material properties in a wide range, and offers great potential for the development of electrochemical biosensors.

Ultraviolet Sensing by Al-doped ZnO Thin Films

International Nuclear Information System (INIS)

Rashid, A.R.A.; Menon, P.S.; Shaari, S.

2011-01-01

We report the fabrication and characterization of an ultraviolet photoconductive sensing by using Al-doped ZnO films. Undoped ZnO, 1 at.% and 2 at% of Al were prepared on quartz glass by sol gel method with annealing temperature of 500 degree Celsius for 1 hour. The presence of spherical shaped nanoparticles were detected for undoped ZnO by using FESEM. The absorption edge shifted to a lower wavelength by doping with Al and excitonic peak can be observed. The band gap values increased by adding Al. I-V curves reveal an improvement in electrical properties when the samples are illuminated by ultraviolet (UV) light with a wavelength of 365 nm. At 1 at.% of Al, the film have a larger increment in photocurrent response when illuminated with UV light compared to undoped ZnO and 2 at.% Al. The thin films have a longer recovery time than response time. (author)

Comportamiento del arrastre de partículas en los gases durante el secado del mineral laterítico en tambores cilíndricos rotatorios

Directory of Open Access Journals (Sweden)

Alexis García-Pérez

2000-03-01

Full Text Available Se utiliza un método estadístico-matemático de planificación de experimentos para la investigación del comportamiento del arrastre de partículas finas en los gases durante el secado del mineral laterítico en uno de los secadores en condiciones normales de operación. En un segundo se eliminaron los levantadores sectoriales en el último tercio del equipo, y se analizó en ambos la influencia de los gases residuales provenientes de la planta de hornos de reducción. Se obtiene la correlación y regresión entre las variables de entrada más importantes que intervienen en el proceso: velocidad de los gases en el interior del cilindro (V, contenido de humedad de los gases (W, y el arrastre de partículas (A como variable de salida. Los resultados obtenidos ofrecen alentadoras perspectivas sobre la generalización industrial de la propuesta.

Effect of sol concentration on the structural, morphological, optical and photoluminescence properties of zirconia thin films

International Nuclear Information System (INIS)

Joy, K.; Maneeshya, L.V.; Thomas, Jijimon K.; Thomas, P.V.

2012-01-01

ZrO 2 thin films were deposited on quartz substrates from 10 wt.%, 20 wt.% and 40 wt.% solutions of Zirconium-n-butoxide in isopropanol by sol–gel dip-coating technique. Higher concentrated sols of 20 wt.% and 40 wt.% exhibited faster gelation, where as 10 wt.% sol remained stable for two months and films synthesized from this sol remained transparent and continuous even for 12 coatings. Ellipsometric study revealed that refractive index of the films increased with increase in sol concentration which is ascribed to the decrease in porosity. X-ray diffraction study showed that a tailoring of grain size from 7.9 to 39.2 nm is possible with increase in sol concentration. Atomic force microscopy studies showed a change in growth mode from vertical to lateral mode with increase in sol concentration. The film surface revealed positive skewness and high kurtosis values which make them favorable for tribological applications. The average optical transmittance in the visible region is highest (greater than 90%) for the film deposited from 10 wt.% sol. The optical band gap decreased from 5.74 to 5.62 eV with increase in the sol concentration. Photoluminescence (PL) spectra of the films exhibit an increase in the emission intensity with increase in sol concentration which substantiates better crystalline quality of the film deposited from 40 wt.% sol and increase in oxygen vacancies. The “Red shift” of the PL spectra with increase in sol concentration originates from the increase in the grain size with sol concentration which makes it suitable for generation of solid state lighting in light emitting diode. - Highlights: ► ZrO 2 thin films were deposited on quartz substrates by sol-gel method. ► Control of grain size with sol concentration. ► Microstructure studies showed a change in growth mode from vertical to lateral mode. ► The optical band gap decreased with increase in grain size and sol concentration. ► Dependence of photoluminescence on particle size

Waveguide fabrication in UV-photocurable sol-gel materials: Influence of the photoinitiating system

International Nuclear Information System (INIS)

Versace, D.L.; Oubaha, M.; Copperwhite, R.; Croutxe-Barghorn, C.; MacCraith, B.D.

2008-01-01

In this paper we identify and explain the different chemical interactions involved between a sol-gel matrix and photoinitiators used in the fabrication of optical waveguides. A well-established sol-gel matrix composed of 3-methacryloxypropyltrimethoxysilane, zirconium n-propoxide and methacrylic acid was developed, and two different photoinitiators (Irgacure (registered) 819 and 1800) were added to the host matrix. Optical microscopy was used to characterise the structure of the waveguides as a function of the photoinitiator nature and concentration, and aging of the hybrid sol-gel material. It is clearly demonstrated that the width of the waveguides is strongly influenced by the sol aging. Furthermore, it is shown that degradation of photoinitiators occurs during the sol-gel process. Oxidation of the phosphonyl groups by the zirconium complex accounts for this results

Time for a Change; Spirit's View on Sol 1843 (Stereo)

Science.gov (United States)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11973 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11973 NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this stereo, full-circle view of the rover's surroundings during the 1,843rd Martian day, or sol, of Spirit's surface mission (March 10, 2009). South is in the middle. North is at both ends. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 36 centimeters downhill earlier on Sol 1854, but had not been able to get free of ruts in soft material that had become an obstacle to getting around the northeastern corner of the low plateau called 'Home Plate.' The Sol 1854 drive, following two others in the preceding four sols that also achieved little progress in the soft ground, prompted the rover team to switch to a plan of getting around Home Plate counterclockwise, instead of clockwise. The drive direction in subsequent sols was westward past the northern edge of Home Plate. This view is presented as a cylindrical-perspective projection with geometric seam correction.

Porous alumina scaffold produced by sol-gel combined polymeric sponge method

Science.gov (United States)

Hasmaliza, M.; Fazliah, M. N.; Shafinaz, R. J.

2012-09-01

Sol gel is a novel method used to produce high purity alumina with nanometric scale. In this study, three-dimensional porous alumina scaffold was produced using sol-gel polymeric sponge method. Briefly, sol gel alumina was prepared by evaporation and polymeric sponge cut to designated sizes were immersed in the sol gel followed by sintering at 1250 and 1550°C. In order to study the cell interaction, the porous alumina scaffold was sterilized using autoclave prior to Human Mesenchymal Stem Cells (HMSCs) seeding on the scaffold and the cell proliferation was assessed by alamarBlue® assay. SEM results showed that during the 21 day period, HMSCs were able to attach on the scaffold surface and the interconnecting pores while maintaining its proliferation. These findings suggested the potential use of the porous alumina produced as a scaffold for implantation procedure.

Properties of Zn O/Cr thin films prepared by Sol-Gel; Propiedades de peliculas delgadas ZnO/Cr preparadas por Sol-Gel

Energy Technology Data Exchange (ETDEWEB)

Tirado G, S.; Olvera A, R., E-mail: tirado@esfm.ipn.mx [IPN, Escuela Superior de Fisica y Matematicas, Edificio 9, Unidad Profesional A. L. M., San Pedro Zacatenco, 07788 Mexico D. F. (Mexico)

2014-08-15

Zn O films and those superficially modified with chromium were deposited on substrates of soda-lime glass, using the Sol-Gel process and the repeated immersion method. Starting from dehydrated zinc acetate was prepared a solution to 0.6 M to ambient temperature in 2-methoxyethanol and monoethanolamine (Mea) stirring magnetically. The Sol was prepared with an aging to seven days and was used to grow a films group with thickness to eight immersions. These same films were superficially modified with several depositions of a chromium nitrate Sol dissolved in ethanol to low concentration. The Zn O films were structurally characterized by X-ray diffraction, its chemical composition by energy dispersive X-ray spectroscopy and its morphology by scanning electron microscopy and atomic force microscopy, as well as their optical properties by UV-vis. Of the obtained results are proposed possible applications. (author)

Salt-assisted and salt-suppressed sol-gel transitions of methylcellulose in water.

Science.gov (United States)

Xu, Y; Wang, C; Tam, K C; Li, L

2004-02-03

The effects of various salts on the sol-gel transition of aqueous methylcellulose (MC) solutions have been studied systematically by means of a micro differential scanning calorimeter. It was found that the heating process was endothermic while the cooling process was exothermic for both MC solutions with and without salts. The addition of salts did not change the patterns of gelation and degelation of MC. However, the salts could shift the sol-gel transition and the gel-sol transition to lower or higher temperatures from a pure MC solution, depending on the salt type. These opposite effects were termed the salt-assisted and salt-suppressed sol-gel transitions. Either the salt-assisted transition or the salt-suppressed sol-gel transition was a function of salt concentration. In addition, each salt was found to have its own concentration limit for producing a stable aqueous solution of MC at a given concentration of MC, which was related to the anionic charge density of the salt. Cations were proved to have weaker effects than anions. The "salt-out strength", defined as the salt effect per mole of anion, was obtained for each anion studied. The thermodynamic mechanisms involved in the salt-assisted and salt-suppressed sol-gel transitions are discussed.

Improved photoluminescence property of CTAB assisted polyaniline-AlZnO nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Mitra, Mousumi; Banerjee, Dipali, E-mail: dipalibanerjeebesu@gmail.com [Department of Physics, Indian Institute of Engineering Science and Technology, Shibpur, Howrah (India); Kargupta, Kajari [Department of Chemical Engineering, Jadavpur University, Kolkata (India); Ganguly, Saibal [Chemical Engineering department, Universiti Teknology Petronas, Tronoh (Malaysia)

2015-06-24

Polyaniline-Al doped ZnO ((PANI-AlZnO:: 70:30) nanocomposite was prepared via in situ chemical oxidative polymerization, while the hexagonal powder of AlZnO was synthesized via sol-gel technique, using Hexadecyltrimethylammonium bromide (CTAB) as a capping agent. The prepared nanocomposite was characterized by High resolution transmission electron microscopy (HRTEM), EDAX, X-ray diffraction (XRD) and Fourier transforms infrared (FTIR) spectra. The optical property of the nanomaterials is examined by photoluminescence (PL) spectra analysis. The XRD pattern confirms the formation of Al doped ZnO as well as PANI. The HRTEM images of the composite showed the formation of hexagonal AlZnO embedded in polyaniline matrix. EDAX spectrum shows the compositional analysis of the nanocomposite. FTIR spectra confirm the formation of nanocomposite of PANI and hexagonal AlZnO. The PL intensity of the nanocomposite is improved as compared to pure AlZnO.

Bio-indicateurs de la fertilité des sols et la perception paysanne à l ...

African Journals Online (AJOL)

SARAH

30 mai 2015 ... d'identifier des bio-indicateurs des sols fertiles et des sols dégradés selon la perception paysanne et des paramètres ..... effet, une augmentation du stock hydrique du sol à ... Fonctionnement et gestion des écosystèmes.

Transport barrier fluctuations governed by SOL turbulence spreading

International Nuclear Information System (INIS)

Ghendrih, Ph.; Sarazin, Y.; Ciraolo, G.; Darmet, G.; Garbet, X.; Grangirard, V.; Tamain, P.; Benkadda, S.; Beyer, P.

2007-01-01

Turbulence spreading, namely turbulent transport extending into a stable region is reported both for the flat density profiles in the far SOL and into a modeled H-mode barrier. It is shown that due to turbulence penetration, the pedestal width fluctuates and that its effective width is a factor 2 smaller than the linear predicted width. Turbulence overshooting throughout the pedestal leads to a non-vanishing turbulent transport within the barrier and provides a coupling of core and SOL turbulence despite the transport barrier

Biocompatibility of bismuth silicate coatings deposited on 316L stainless steel by sol-gel process

Directory of Open Access Journals (Sweden)

Jorge Hernando Bautista-Ruiz

2017-01-01

Full Text Available Películas delgadas de silicato de bismuto (BSO se han fabricado mediante el proceso sol-gel. El sol estable se sintetizó utilizando nitrato de bismuto (III pentahidrato y tetraetil-ortosilicato (TEOS. Las películas fueron depositadas a 1500 rpm mediante la técnica de centrifugado. Los recubrimientos se caracterizaron por microscopía de fuerza atómica (AFM, microscopía electrónica de barrido (SEM, difracción de rayos-X (DRX y se midió el espesor de las películas. El objetivo de este estudio fue evaluar la adhesión y la proliferación en células de osteoblastos, mediante el ensayo MMT, al incubarse sobre películas BSO en sustratos de 316L. Se concluyó que el crecimiento de los osteoblastos es homogéneo en la superficie de las películas, indicando que el medio ofrecido por los recubrimientos no presenta actividad citotóxica y favorece los niveles de crecimiento celular en comparación con los resultados obtenidos para los sustratos de acero inoxidable.

Influence of Maltodextrin and Spray Drying Process Conditions on Sugarcane Juice Powder Quality / Influencia de la Maltodextrina y Condiciones del Proceso de Secado por Aspersión en la Calidad del Polvo de Jugo de Caña Panelera

Directory of Open Access Journals (Sweden)

Esteban Largo Ávila

2014-12-01

Full Text Available Abstract. Food powder liquid extracts obtained from fruits andvegetables can be manufactured using spray drying technologieswhile maintaining the quality attributes that are required by theindustrial sector. The aim of this study was to evaluate the effectof maltodextrin and spray drying process conditions on sugarcanejuice powder. A central composite design was used with a responsesurface analysis of four factors: (A maltodextrin (10-20%, (Binlet air temperature (130-150 °C, (C outlet air temperature (75-85 °C and (D atomization speed (22,000–26,000 rpm. Moisture,hygroscopicity, solubility, effective recovery and formation ofdeposits on the walls presented significant differences (P<0.05with respect to all factors, while, for water activity, no statisticaldifferences were observed. The optimization of the factors foundfor the drying operating conditions were: (A 20%, (B 130 °C, (C75 °C and (D 22,000 rpm, respectively. / Resumen. Polvos alimentarios de extractos líquidos obtenidos apartir de frutas y vegetales pueden ser manufacturados usandotecnologías de secado por aspersión y mantener los atributosde calidad requeridos en el sector industrial. El objetivo de esteestudio fue evaluar el efecto de la adición de maltodextrina y lascondiciones de procesamiento por secado por aspersión en laobtención de polvo de jugo de caña. Un diseño central compuestoy análisis mediante superficies de respuesta con cuatro factoresestadísticos fue establecido: (A maltodextrina (10-20%, (Btemperatura del aire de secado a la entrada (130-150 °C, (Ctemperatura del aire a la salida (75-85 °C y (D velocidad deldisco atomizador (22.000–26.000 rpm. Los resultados mostraronque las variables contenido de humedad del producto, solubilidad,recuperación efectiva y formación de depósitos de sólidos en lapared del secador son estadísticamente significativos (P<0,05 conrespecto a los factores estudiados, mientras que la actividad deagua del producto

Novel hybrid sol-gel coatings for corrosion protection of AZ31B magnesium alloy

International Nuclear Information System (INIS)

Lamaka, S.V.; Montemor, M.F.; Galio, A.F.; Zheludkevich, M.L.; Trindade, C.; Dick, L.F.; Ferreira, M.G.S.

2008-01-01

This work aims to develop and study new anticorrosion films for AZ31B magnesium alloy based on the sol-gel coating approach. Hybrid organic-inorganic sols were synthesized by copolymerization of epoxy-siloxane and titanium or zirconium alkoxides. Tris(trimethylsilyl) phosphate was also used as additive to confer additional corrosion protection to magnesium-based alloy. A sol-gel coating, about 5-μm thick, shows good adhesion to the metal substrate and prevents corrosion attack in 0.005 M NaCl solution for 2 weeks. The sol-gel coating system doped with tris(trimethylsilyl)-phosphate revealed improved corrosion protection of the magnesium alloy due to formation of hydrolytically stable Mg-O-P chemical bonds. The structure and the thickness of the sol-gel film were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The corrosion behaviour of AZ31B substrates pre-treated with the sol-gel derived hybrid coatings was tested by electrochemical impedance spectroscopy (EIS). The chemical composition of the silylphosphate-containing sol-gel film at different depths was investigated by X-ray photoelectron spectroscopy (XPS) with depth profiling

Formulation and evaluation of antimicrobial activity of Morus alba sol-gel against periodontal pathogens

Directory of Open Access Journals (Sweden)

Shilpa Gunjal

2015-01-01

Full Text Available Background: Periodontitis has a multifactorial etiology, with primary etiologic agents being pathogenic bacteria that reside in the subgingival area. Recent advances in the field of alternative medicine introduced various herbal products for the treatment of periodontitis. Aim: To assess and compare the antimicrobial activity of Morus alba sol-gel with chlorhexidine sol-gel against ATCC standard strains of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Tannerella forsythia. Materials and Methods: Crude extract of Morus alba leaves was prepared by Soxhlet method by using ethanol as a solvent. Phytochemical screening of the crude extract of M. alba was performed to check the various chemical constituents. M. alba sol-gel and chlorhexidine sol-gel were formulated using Pluronic f127 and Pluronic f108 and compared for their antimicrobial activity. The minimum inhibitory concentration of both the gels was performed using agar well diffusion technique. Results: The minimum inhibitory concentration of M. alba sol-gel and chlorhexidine sol-gel against A. actinomycetemcomitans is 19 and 17 mm, T. forsythia is 12 and 21 mm, and P. gingivalis is 16 and 18 mm, respectively. Conclusion: Both M. alba and chlorhexidine sol-gel exhibited potent antimicrobial activity against periodontal pathogens.

Sol-gel antireflective coating on plastics

Science.gov (United States)

Ashley, Carol S.; Reed, Scott T.

1990-01-01

An antireflection film made from a reliquified sol-gel hydrolyzation, condensation polymeric reaction product of a silicon, alkoxides and/or metal alkoxides, or mixtures thereof. The film is particularly useful for coating plastics.

Patterned transparent zinc oxide films produced by sol-gel embossing

Energy Technology Data Exchange (ETDEWEB)

Rao, J.; Koh, L.H.K.; Crean, G.M. [Tyndall National Institute, Lee Maltings, Prospect Row, Cork (Ireland); Department of Microelectronic Engineering, University College Cork, Cork (Ireland); O' Brien, S. [Tyndall National Institute, Lee Maltings, Prospect Row, Cork (Ireland); Winfield, R.J.

2008-08-15

A low cost zinc oxide embossing technique is reported as a method of fabricating structures relevant to a variety of applications. A zinc based sol-gel material was prepared from zinc acetate[Zn(C{sub 2}H{sub 3}O{sub 2}){sub 2}], monoethanolamine[H{sub 2}NC{sub 2}H{sub 4}OH] and isopropanol. The sol-gel was cast into a polydimethylsiloxane (PDMS) mould a track design, placed in contact with the substrate and dried under vacuum at 70 C for 3 hours. The formed track pattern was further densified to provide a stable conductor film that retained the embossed shape. An optimum Zn sol-gel content of 0.6 M was identified. The embossed films had a transparency of greater than 83% in the visible region. The optical bandgap energy was evaluated to be 3.306 eV. The influence of ZnO sol-gel film synthesis and embossing parameters on the microstructure, morphology and optical transparency of fabricated structures is described. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Amoeba-like self-oscillating polymeric fluids with autonomous sol-gel transition.

Science.gov (United States)

Onoda, Michika; Ueki, Takeshi; Tamate, Ryota; Shibayama, Mitsuhiro; Yoshida, Ryo

2017-07-13

In the field of polymer science, many kinds of polymeric material systems that show a sol-gel transition have been created. However, most systems are unidirectional stimuli-responsive systems that require physical signals such as a change in temperature. Here, we report on the design of a block copolymer solution that undergoes autonomous and periodic sol-gel transition under constant conditions without any on-off switching through external stimuli. The amplitude of this self-oscillation of the viscosity is about 2,000 mPa s. We also demonstrate an intermittent forward motion of a droplet of the polymer solution synchronized with the autonomous sol-gel transition. This polymer solution bears the potential to become the base for a type of slime-like soft robot that can transform its shape kaleidoscopically and move autonomously, which is associated with the living amoeba that moves forward by a repeated sol-gel transition.

CONSTRUCCIÓN Y VALIDACIÓN DE UN SECADOR SOLAR PARA MADERA ASERRADA

Directory of Open Access Journals (Sweden)

M. Fuentes-Salinas

2003-01-01

Full Text Available Este trabajo consistió en construir y probar un secador solar para 7.075 m3 de madera aserrada, destinado a los pequeños y medianos productores forestales. Para la construcción se utilizaron materiales disponibles en cualquier región de México y para evaluar su funcionamiento se usó madera de Pinus hartwegii de 2.54 cm de espesor, 2.50 m de largo y anchos variables. La cámara está construida tipo invernadero, con un piso de concreto, estructura metálica para soportar el colector solar, muros a base de bastidores de madera y forro de plástico, y está equipado con dos ventiladores axiales con motor de ½ HP. Para la validación se hicieron dos ensayos de secado, uno en el secador solar y otro secado al aire libre, teniendo como resultado que la madera en el secador solar se secó en el 50 % del tiempo requerido para el secado al aire libre, a un contenido de humedad final del 10 y 12 % respectivamente; además, que la calidad de la madera resultó también mejor en el secador solar. El costo de construcción del secador solar fue de $ 5,227. 25 US Dls. y se estimó un tiempo de construcción de 21 días.

The influence of sol on the behavior of melting and nonisothermal crystallization kinetic of radiation cross-linking HDPE

International Nuclear Information System (INIS)

Deng Pengyang; Xie Hongfeng; Deng Mingxiao; Zhong Xiaoguang

2000-01-01

By using DSC, the behavior of second melting and nonisothermal crystallization of pure gel pure sol and sol-gel blend of radiation crosslinking HDPE was studied. The authors found that, because of the existence of sol, there is notable difference between pure gel and pure sol or sol-gel blend. Under the same dose, the melting point and crystallization temperature of pure sol and sol-gel blend are higher than that of pure gel. At the same time, the authors also found that the Avrami exponent of original PE, pure sol and sol-gel blend is the similar to each other and different to that of pure gel, which means that the procedure of nucleation and growth of these samples is the same and also different to that of pure gel

Opportunity's Surroundings After Sol 1820 Drive

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009). South is at the center; north at both ends. The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock. This view is presented as a cylindrical projection with geometric seam correction.

Uranium Dioxide Powder Flow ability Improvement Using Sol-Gel

International Nuclear Information System (INIS)

Juanda, D.; Sambodo Daru, G.

1998-01-01

The improvement of flow ability characteristics of uranium dioxide powder has been done using sol-gel process. To anticipate a pellet mass production with uniform pellet dimension, the uranium dioxide powder must be have a spherical form. Uranium dioxide spherical powder has been diluted in acid transformed into sol colloidal solution. To obtain uranium dioxide spherical form, the uranium sol-colloidal solution has been dropped in a hot paraffin ( at the temperature of 90 0 C) to form gelatinous colloid and then dried at 800 0 C, and sintered at the temperature of 1700 0 C. The flow ability of spherical uranium dioxide powder has been examined by using Flowmeter Hall (ASTM. B. 213-46T). The measurement result reveals that the spherical uranium dioxide powder has a flow ability twice than that of unprocessed uranium dioxide powder

Profiles and fluctuations in edge and SOL turbulence

DEFF Research Database (Denmark)

Naulin, Volker; Xu, G.; Vianello, N.

2012-01-01

propagating structures and parallel transport sets up the observed profiles and how intermittency influences edge conditions. The filamentary blob structures also transport and generate currents in the SOL, which can be investigated by means of local magnetic diagnostics. Finally, the ratio of ion to electron...... temperature in the SOL is an important measure for the influence of finite larmor radius effects on the propagation properties of blobs. Numerical investigations indicate that these effects can lead to an increased self confinement and radial reach of these structures. © 2012 WILEY-VCH Verlag GmbH & Co. KGa...

Rationale and Design of the Echocardiographic Study of Hispanics/Latinos (ECHO-SOL).

Science.gov (United States)

Rodriguez, Carlos J; Dharod, Ajay; Allison, Matthew A; Shah, Sanjiv J; Hurwitz, Barry; Bangdiwala, Shrikant I; Gonzalez, Franklyn; Kitzman, Dalane; Gillam, Linda; Spevack, Daniel; Dadhania, Rupal; Langdon, Sarah; Kaplan, Robert

2015-01-01

Information regarding the prevalence and determinants of cardiac structure and function (systolic and diastolic) among the various Hispanic background groups in the United States is limited. The Echocardiographic Study of Latinos (ECHO-SOL) ancillary study recruited 1,824 participants through a stratified-sampling process representative of the population-based Hispanic Communities Health Study - Study of Latinos (HCHS-SOL) across four sites (Bronx, NY; Chicago, Ill; San Diego, Calif; Miami, Fla). The HCHS-SOL baseline cohort did not include an echo exam. ECHO-SOL added the echocardiographic assessment of cardiac structure and function to an array of existing HCHS-SOL baseline clinical, psychosocial, and socioeconomic data and provides sufficient statistical power for comparisons among the Hispanic subgroups. Standard two-dimensional (2D) echocardiography protocol, including M-mode, spectral, color and tissue Doppler study was performed. The main objectives were to: 1) characterize cardiac structure and function and its determinants among Hispanics and Hispanic subgroups; and 2) determine the contributions of specific psychosocial factors (acculturation and familismo) to cardiac structure and function among Hispanics. We describe the design, methods and rationale of currently the largest and most comprehensive study of cardiac structure and function exclusively among US Hispanics. ECHO-SOL aims to enhance our understanding of Hispanic cardiovascular health as well as help untangle the relative importance of Hispanic subgroup heterogeneity and sociocultural factors on cardiac structure and function.

Preparation and characterization of conductive and transparent ruthenium dioxide sol-gel films.

Science.gov (United States)

Allhusen, John S; Conboy, John C

2013-11-27

RuO2 conductive thin films were synthesized using the sol-gel method and deposited onto transparent insulating substrates. The optical transmission, film thickness, surface morphology and composition, resistivity, and spectroelectrochemical performance have been characterized. The optical transmission values of these films ranged from 70 to 89% in the visible region and from 56 to 88% in the infrared region. Resistivity values of the RuO2 sol-gel films varied from 1.02 × 10(-3) to 1.13 Ω cm and are highly dependent on the initial solution concentration of RuO2 in the sol-gel. The RuO2 sol-gel films were used as electrodes for the electrochemical oxidation and reduction of ferrocenemethanol. The electrochemical behavior of our novel RuO2 sol-gel films was compared to that of a standard platinum disk electrode and showed no appreciable differences in the half-wave potential (E1/2). The mechanical and chemical stability of the coatings was tested by physical abrasion and exposure to highly acidic, oxidizing Piranha solution. Repeated exposure to these extreme conditions did not result in any appreciable decline in electrochemical performance. Finally, the use of the novel RuO2 sol-gel conductive and transparent films was demonstrated in a spectroelectrochemistry experiment in which the oxidation and reduction of ferrocenemethanol was monitored via UV-vis spectroscopy as the applied potential was cycled.

Understanding the SOL flow in L-mode plasma on divertor tokamaks, and its influence on the plasma transport

International Nuclear Information System (INIS)

Asakura, Nobuyuki

2007-01-01

Significant progress has been made in understanding the driving mechanisms in SOL mass transport along the magnetic field lines (SOL flow). SOL flow measurements by Mach probes and impurity plume have been performed in L-mode plasma at various poloidal locations in divertor tokamaks. All results showed common SOL flow patterns: subsonic flow with parallel Mach number (M parallel ) of 0.2-1 was generated from the Low-Field-Side (LFS) SOL to the High-Field-Side (HFS) divertor for the ion ∇B drift towards the divertor. The SOL flow pattern was formed mainly by LFS-enhanced asymmetry in diffusion and by classical drifts. In addition, divertor detachment and/or intense puffing-and-pump enhanced the HFS SOL flow. Most codes have incorporated drift effects, and asymmetric diffusion was modelled to simulate the fast SOL flow. Influences of the fast SOL flow on the impurity flow in the SOL, shielding from core plasma, and deposition profile, were directly observed in experiments

Optical Studies on Sol-Gel Derived Lead Chloride Crystals

OpenAIRE

Rejeena, I; Lillibai, B; Nithyaja, B; Nampoori, P.N V; Radhakrishnan, P

2013-01-01

Optical characterization of lead chloride crystals prepared by sol-gel method is reported. The relevant sol-gel technique is used for the preparation of PbCl2 samples with five different types. In this paper, we report the absorption and fluorescence behaviour of pure, UV& IR irradiated and electric & magnetic field applied lead chloride crystal samples in solution phase at two different concentrations. Optical bandgap and emission studies of these crystals are also done.

Effect of different sol concentrations on the properties of nanocrystalline ZnO thin films grown on FTO substrates by sol-gel spin-coating

International Nuclear Information System (INIS)

Kim, Ikhyun; Kim, Younggyu; Nam, Giwoong; Kim, Dongwan; Park, Minju; Kim, Haeun; Lee, Wookbin; Leem, Jaeyoung; Kim, Jongsu; Kim, Jin Soo

2014-01-01

Nanocrystalline ZnO thin films grown on fluorine-doped tinoxide (FTO) substrates were fabricated using the spin-coating method. The structural and the optical properties of the ZnO thin films prepared using different sol concentrations were investigated by using field-emission scanning electron microscopy (FE-SEM), X-ray diffractometry (XRD), photoluminescence (PL) measurements, and ultraviolet-visible (UV-vis) spectrometry. The surface morphology of the ZnO thin films, as observed in the SEM images, exhibited a mountain-chain structure. XRD results indicated that the thin films were preferentially orientated along the direction of the c-axis and that the grain size of the ZnO thin films increased with increasing sol concentration. The PL spectra showed a strong ultraviolet emission peak at 3.22 eV and a broad orange emission peak at 2.0 eV. The intensities of deep-level emission (DLE) gradually increased with increasing sol concentration from 0.4 to 1.0 M. The transmittance spectra of the ZnO thin films showed that the ZnO thin films were transparent (∼85%) in the visible region and exhibited sharp absorption edges at 375 nm. Thus, The Urbach energy of ZnO thin films decreased with increasing sol concentration.

Spirit Near 'Stapledon' on Sol 1802 (Vertical)

Science.gov (United States)

2009-01-01

NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. North is at the top. This view is presented as a vertical projection with geometric seam correction. Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches). Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica. The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

Spirit Near 'Stapledon' on Sol 1802 (Polar)

Science.gov (United States)

2009-01-01

NASA Mars Exploration Rover Spirit used its navigation camera for the images assembled into this full-circle view of the rover's surroundings during the 1,802nd Martian day, or sol, (January 26, 2009) of Spirit's mission on the surface of Mars. North is at the top. This view is presented as a polar projection with geometric seam correction. Spirit had driven down off the low plateau called 'Home Plate' on Sol 1782 (January 6, 2009) after spending 12 months on a north-facing slope on the northern edge of Home Plate. The position on the slope (at about the 9-o'clock position in this view) tilted Spirit's solar panels toward the sun, enabling the rover to generate enough electricity to survive its third Martian winter. Tracks at about the 11-o'clock position of this panorama can be seen leading back to that 'Winter Haven 3' site from the Sol 1802 position about 10 meters (33 feet) away. For scale, the distance between the parallel wheel tracks is about one meter (40 inches). Where the receding tracks bend to the left, a circular pattern resulted from Spirit turning in place at a soil target informally named 'Stapledon' after William Olaf Stapledon, a British philosopher and science-fiction author who lived from 1886 to 1950. Scientists on the rover team suspected that the soil in that area might have a high concentration of silica, resembling a high-silica soil patch discovered east of Home Plate in 2007. Bright material visible in the track furthest to the right was examined with Spirit's alpha partical X-ray spectrometer and found, indeed, to be rich in silica. The team laid plans to drive Spirit from this Sol 1802 location back up onto Home Plate, then southward for the rover's summer field season.

Synthesis of yttrium silicate luminescent materials by sol-gel method

International Nuclear Information System (INIS)

Arkhipov, D.V.; Vasina, O.Yu.; Popovich, N.V.; Galaktionov, S.S.; Soshchin, N.P.

1996-01-01

Several yttrium-silicate composition with Y 2 O 3 content within 44-56% have been synthesized. it is ascertained that employment of sol-gel technique permits preparation of luminescent materials on yttrium silicate basis, which compare favourably with bath-produced specimens. The influence of phase composition of sol-gel phosphors on basic performance indices: intensity and luminescence spectrum, has been analyzed

Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation

Science.gov (United States)

Gąsiorek, Jolanta; Babiarczuk, Bartosz; Kaleta, Jerzy; Jones, Walis; Krzak, Justyna

2018-01-01

Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented. PMID:29373540

Spirit's View Beside 'Home Plate' on Sol 1823

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit used its navigation camera to take the images that have been combined into this 180-degree view of the rover's surroundings during the 1,823rd Martian day, or sol, of Spirit's surface mission (Feb. 17, 2009). The center of the view is toward the south-southwest. The rover had driven 7 meters (23 feet) eastward earlier on Sol 1823, part of maneuvering to get Spirit into a favorable position for climbing onto the low plateau called 'Home Plate.' However, after two driving attempts with negligible progress during the following three sols, the rover team changed its strategy for getting to destinations south of Home Plate. The team decided to drive Spirit at least partway around Home Plate, instead of ascending the northern edge and taking a shorter route across the top of the plateau. Layered rocks forming part of the northern edge of Home Plate can be seen near the center of the image. Rover wheel tracks are visible at the lower edge. This view is presented as a cylindrical projection with geometric seam correction.

Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation.

Science.gov (United States)

Gąsiorek, Jolanta; Szczurek, Anna; Babiarczuk, Bartosz; Kaleta, Jerzy; Jones, Walis; Krzak, Justyna

2018-01-26

Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

Opportunity's View After Long Drive on Sol 1770 (Stereo)

Science.gov (United States)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11791 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11791 NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo, full-circle view of the rover's surroundings just after driving 104 meters (341 feet) on the 1,770th Martian day, or sol, of Opportunity's surface mission (January 15, 2009). This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). Prior to the Sol 1770 drive, Opportunity had driven less than a meter since Sol 1713 (November 17, 2008), while it used the tools on its robotic arm first to examine a meteorite called 'Santorini' during weeks of restricted communication while the sun was nearly in line between Mars and Earth, then to examine bedrock and soil targets near Santorini. The rover's position after the Sol 1770 drive was about 1.1 kilometer (two-thirds of a mile) south southwest of Victoria Crater. Cumulative odometry was 13.72 kilometers (8.53 miles) since landing in January 2004, including 1.94 kilometers (1.21 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008). This view is presented as a cylindrical-perspective projection with geometric seam correction.

Magnetic resonance as a structural probe of a uranium (VI) sol-gel process

International Nuclear Information System (INIS)

King, C.M.; Thompson, M.C.; Buchanan, B.R.; King, R.B.; Garber, A.R.

1989-01-01

NMR investigations on the ORNL process for sol-gel synthesis of microspherical nuclear fuel (UO 2 ), has been useful in sorting out the chemical mechanism in the sol-gel steps. 13 C, 15 N, and 1 H NMR studies on the HMTA gelation agent (Hexamethylene tetramine, C 6 H l2 N 4 ) has revealed near quantitative stability of this adamantane-like compound in the sol-Gel process, contrary to its historical role as an ammonia source for gelation from the worldwide technical literature. 17 0 NMR of uranyl (UO 2 ++ ) hydrolysis fragments produced in colloidal sols has revealed the selective formation of a uranyl trimer, [(UO 2 ) 3 (μ 3 -O)(μ 2 -OH) 3 ] + , induced by basic hydrolysis with the HMTA gelation agent. Spectroscopic results show that trimer condensation occurs during sol-gel processing leading to layered polyanionic hydrous uranium oxides in which HMTAH + is occluded as an ''intercalation'' cation. Subsequent sol-gel processing of microspheres by ammonia washing results in in-situ ion exchange and formation of a layered hydrous ammonium uranate with a proposed structural formula of (NH 4 ) 2 [(UO 2 ) 8 O 4 (OH) 10 ] · 8H 2 0. This compound is the precursor to sintered U0 2 ceramic fuel

Foldable and Cytocompatible Sol-gel TiO2 Photonics.

Science.gov (United States)

Li, Lan; Zhang, Ping; Wang, Wei-Ming; Lin, Hongtao; Zerdoum, Aidan B; Geiger, Sarah J; Liu, Yangchen; Xiao, Nicholas; Zou, Yi; Ogbuu, Okechukwu; Du, Qingyang; Jia, Xinqiao; Li, Jingjing; Hu, Juejun

2015-09-07

Integrated photonics provides a miniaturized and potentially implantable platform to manipulate and enhance the interactions between light and biological molecules or tissues in in-vitro and in-vivo settings, and is thus being increasingly adopted in a wide cross-section of biomedical applications ranging from disease diagnosis to optogenetic neuromodulation. However, the mechanical rigidity of substrates traditionally used for photonic integration is fundamentally incompatible with soft biological tissues. Cytotoxicity of materials and chemicals used in photonic device processing imposes another constraint towards these biophotonic applications. Here we present thin film TiO2 as a viable material for biocompatible and flexible integrated photonics. Amorphous TiO2 films were deposited using a low temperature (<250 °C) sol-gel process fully compatible with monolithic integration on plastic substrates. High-index-contrast flexible optical waveguides and resonators were fabricated using the sol-gel TiO2 material, and resonator quality factors up to 20,000 were measured. Following a multi-neutral-axis mechanical design, these devices exhibit remarkable mechanical flexibility, and can sustain repeated folding without compromising their optical performance. Finally, we validated the low cytotoxicity of the sol-gel TiO2 devices through in-vitro cell culture tests. These results demonstrate the potential of sol-gel TiO2 as a promising material platform for novel biophotonic devices.

Alkali-activated slag mortars reinforced with ar glassfibre. Performance and properties

Directory of Open Access Journals (Sweden)

Amat, T.

2006-09-01

Full Text Available In light of the practical problem posed by the high drying shrinkage rate exhibited by alkali-activated slag (AAS,due to these materials exhibited a high drying shrinkage the present study analyzes the behaviour of alkali-activated slag mortars reinforced with alkali-resistant (AR glass fiber especially designed to reduce drying shrink aging cementitious systems. To this end, both alkali-activated slag and reference Portland cement mortars were prepared, with and without AR fiber (in dosages ranging from 0 to 1.1% by weight of the binder. These mortars were subjected to the following tests: drying shrinkage,mechanical strength after 2, 7 and 28 days, toughness,and high temperature. The microstructure of the materials was also studied by SEM/EDX techniques. At a percentage of 0.22%, AR fiber was found to induce a significant reduction (over 20% in drying shrinkage, without detracting from the fine resistance strength, of alkali activated slag mortar. Moreover, plain activated slag mortars recovered 20% of their initial mechanical strength after exposure to high temperatures, and ins specimens reinforced with glass fiber at a rate of 0.22%,recovery climbed to 50%.El principal problema tecnológico de los cementos de escoria activada alcalinamente (AAS es su elevada retracción al secado. Por ello, en el presente trabajo se estudia el comportamiento de morteros de escoria activada alcalinamente reforzados con fibras de vidrio alcali-resistentes (AR, especialmente diseñadas para reducir la retracción al secado en sistema cementantes. Para ello se prepararon morteros de escoria activada alcalinamente y de cemento Portland como material de referencia. El porcentaje de fibra AR en los morteros varió entre 0-1,1% en peso de ligante. Los morteros preparados fueron sometidos a los siguientes ensayos:retracción al secado, resistencias mecánicas a 2, 7 y 28 días,ensayos de tenacidad, resistencia al impacto y comportamiento resistente frente a altas

Sol-Gel Precursors for Ceramics from Minerals Simulating Soils from the Moon and Mars

Science.gov (United States)

Sibille, Laurent; Gavira-Gallardo, Jose-Antonio; Hourlier-Bahloul, Djamila

2003-01-01

Recent NASA mission plans for the human exploration of our Solar System has set new priorities for research and development of technologies necessary to enable a long-term human presence on the Moon and Mars. The recovery and processing of metals and oxides from mineral sources on other planets is under study to enable use of ceramics, glasses and metals by explorer outposts. We report some preliminary results on the production of sol-gel precursors for ceramic products using mineral resources available in Martian or Lunar soil. The presence of SiO2, TiO2, and A12O3 in both Martian (44 wt.% SiO2, 1 wt.% TiO2, 7 wt.% Al2O3) and Lunar (48 wt.% SiO2, 1.5 wt.% TiO2, 16 wt.% Al2O3) soils and the recent developments in chemical processes to solubilize silicates using organic reagents and relatively little energy indicate that such an endeavor is possible. In order to eliminate the risks involved in the use of hydrofluoric acid to dissolve silicates, two distinct chemical routes are investigated to obtain soluble silicon oxide precursors from Lunar and Martian simulant soils. Clear sol-gel precursors have been obtained by dissolution of silica from Lunar simulant soil in basic ethylene glycol (C2H4(OH)2) solutions to form silicon glycolates. Thermogravimetric Analysis and X-ray Photoelectron Spectroscopy were used to characterize the elemental composition and structure of the precursor molecules. Further concentration and hydrolysis of the products was performed to obtain gel materials for evaluation as ceramic precursors. In the second set of experiments, we used the same starting materials to synthesize silicate esters in acidified alcohol mixtures. Preliminary results indicate the presence of silicon alkoxides in the product of distillation.

Sol-Gel Synthesis Of Aluminoborosilicate Powders

Science.gov (United States)

Bull, Jeffrey; Leiser, Daniel; Selvaduray, Guna

1992-01-01

Application of sol-gel process to synthesis of aluminoborosilicate powders shows potential for control of microstructures of materials. Development of materials having enhanced processing characteristics prove advantageous in extending high-temperature endurance of fibrous refractory composite insulation made from ceramic fibers.

Fast-wave power flow along SOL field lines in NSTX and the associated power deposition profile across the SOL in front of the antenna

International Nuclear Information System (INIS)

Perkins, R.J.; Bell, R.E.; Diallo, A.; Gerhardt, S.; Hosea, J.C.; Jaworski, M.A.; LeBlanc, B.P.; Kramer, G.J.; Maingi, R.; Phillips, C.K.; Podestà, M.; Roquemore, L.; Scotti, F.; Ahn, J.-W.; Gray, T.K.; Green, D.L.; McLean, A.; Ryan, P.M.; Jaeger, E.F.; Sabbagh, S.

2013-01-01

Fast-wave heating and current drive efficiencies can be reduced by a number of processes in the vicinity of the antenna and in the scrape-off layer (SOL). On NSTX from around 25% to more than 60% of the high-harmonic fast-wave power can be lost to the SOL regions, and a large part of this lost power flows along SOL magnetic field lines and is deposited in bright spirals on the divertor floor and ceiling. We show that field-line mapping matches the location of heat deposition on the lower divertor, albeit with a portion of the heat outside of the predictions. The field-line mapping can then be used to partially reconstruct the profile of lost fast-wave power at the midplane in front of the antenna, and the losses peak close to the last closed flux surface as well as the antenna. This profile suggests a radial standing-wave pattern formed by fast-wave propagation in the SOL, and this hypothesis will be tested on NSTX-U. RF codes must reproduce these results so that such codes can be used to understand this edge loss and to minimize RF heat deposition and erosion in the divertor region on ITER. (paper)

Laser sintering of doped strontium aluminate via modified sol-gel for use as a ceramic pigment; Sinterizacao a laser do aluminato de estroncio dopado via sol-gel modificado para aplicacao como pigmento ceramico

Energy Technology Data Exchange (ETDEWEB)

Soares, F.M. dos S.; Valerio, M.E.G. [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil)

2017-01-15

Powder of Dy{sup 3+} co-doped SrAl{sub 2}O{sub 4} :Eu{sup 3+} was produced via proteic sol-gel method, a modified sol-gel route which allows the formation of oxides at lower temperatures than other methods. CO{sub 2} laser sintering was used as a method for heat treatment, effective in reducing trivalent europium ions in doped samples. Thermal analysis of the precursors, performed by TG and DTA, revealed that the crystallization of SrAl{sub 2}O{sub 4} phase occurred at approximately 1060 °C. X-ray diffraction showed that the samples, before and after sintering, had monoclinic and hexagonal phases formation. DLS technique revealed the presence of nanosized and micrometric particles, and particle agglomerates, confirmed by SEM images. Micrographs of the fracture surface of a sintered pellet revealed a high degree of densification caused by heat treatment. Photoluminescence measurements showed that the samples after synthesis and before heat treatment with laser had reddish emission, composed of characteristic narrow emission lines from Eu{sup 3+} and more intense emission when the samples were excited at 265 nm. The laser treatment promoted the reduction of Eu{sup 3+} to Eu{sup 2+} and this effect was confirmed by the presence of a wide emission band in the green region of the spectrum with a maximum emission obtained after excitation at 350 nm. The luminescent decay time of the thermally treated sample was approximately 100 min. Via XRF measurements of acquired frit and DTA and TG of the frit, pigment and mixtures of both, it was noticed good compatibility in terms of thermal processes, that indicated that the pigment has a potential to be used in ceramic tiles. (author)

Electrochemical corrosion behavior of composite MAO/sol-gel coatings on magnesium alloy AZ91D using combined micro-arc oxidation and sol-gel technique

International Nuclear Information System (INIS)

Shang Wei; Chen Baizhen; Shi Xichang; Chen Ya; Xiao Xiang

2009-01-01

Protective composite coatings were obtained on a magnesium alloy by micro-arc oxidation (MAO) and sol-gel technique. The coatings consisted of a MAO layer and a sol-gel layer. The microstructure and composition of the MAO coating and the composite coatings were analyzed by scanning electron microscopy (SEM) and energy dispersive X-rays (EDX). Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and total immersion tests were used to evaluate the corrosion behavior of these coatings in a 3.5 wt.% NaCl solution. The results show that the sol-gel layer provides corrosion protection by physically sealing the pores in the MAO coating and acting as a barrier. The composite coatings can suppress the corrosion process by preventing the corrosive ions from transferring or diffusing to the magnesium alloy substrate. This enhances the corrosion resistance of the magnesium alloy AZ91D significantly

Controlled release of vancomycin from thin sol-gel films on implant surfaces successfully controls osteomyelitis.

Science.gov (United States)

Adams, Christopher S; Antoci, Valentin; Harrison, Gerald; Patal, Payal; Freeman, Terry A; Shapiro, Irving M; Parvizi, Javad; Hickok, Noreen J; Radin, Shula; Ducheyne, Paul

2009-06-01

Peri-prosthetic infection remains a serious complication of joint replacement surgery. Herein, we demonstrate that a vancomycin-containing sol-gel film on Ti alloy rods can successfully treat bacterial infections in an animal model. The vancomycin-containing sol-gel films exhibited predictable release kinetics, while significantly inhibiting S. aureus adhesion. When evaluated in a rat osteomyelitis model, microbiological analysis indicated that the vancomycin-containing sol-gel film caused a profound decrease in S. aureus number. Radiologically, while the control side showed extensive bone degradation, including abscesses and an extensive periosteal reaction, rods coated with the vancomycin-containing sol-gel film resulted in minimal signs of infection. MicroCT analysis confirmed the radiological results, while demonstrating that the vancomycin-containing sol-gel film significantly protected dense bone from resorption and minimized remodeling. These results clearly demonstrate that this novel thin sol-gel technology can be used for the targeted delivery of antibiotics for the treatment of periprosthetic as well as other bone infections. Copyright 2008 Orthopaedic Research Society

Preparation of ThO2 sols having colloid-size distributions suitable for gelation into microspheres

International Nuclear Information System (INIS)

Yamagishi, Shigeru; Takahashi, Yoshihisa; Shiba, Koreyuki

1984-01-01

Production conditions of ThO 2 sols suitable for gelling into crackfree microspheres in an external gelation process were studied. The sols were prepared under pH control and colloid size distributions of the resulting sols were determined. The gelation was carried out by using hexone as a drop formation medium and ammonia as a gelling agent. The crackfree gelation was achieved by the use of ThO 2 sols produced under favorable pH, which were large in colloid size and high in colloid fraction. ''Preneutralization'' preceding the pH control is also important for the good sols. Analyzing the colloid fraction, colloid size and crystallite size of sol, it was found that, under the favorable pH, colloid nuclei generating at early stages grow in the form of single-crystals with their number kept constant and, after cooling, they exist as polycrystalline colloids. The mechanism of cracking is also discussed. (author)

The Influence of Microgravity on Silica Sol-Gel Formation

Science.gov (United States)

Sibille, L.; Smith, D. D.; Cronise, R.; Hunt, A. J.; Wolfe, D. B.; Snow, L. A.; Oldenberg, S.; Halas, N.; Rose, M. Franklin (Technical Monitor)

2000-01-01

We discuss space-flight experiments involving the growth of silica particles and gels. The effect of microgravity on the growth of silica particles via the sol-gel route is profound. In four different recipes spanning a large range of the parameter space that typically produces silica nanoparticles in unit-gravity, low-density gel structures were instead formed in microgravity. The particles that did form were generally smaller and more polydisperse than those grown on the ground. These observations suggest that microgravity reduces the particle growth rate, allowing unincorporated species to form aggregates and ultimately gel. Hence microgravity favors the formation of more rarefied structures, providing a bias towards diffusion-limited cluster-cluster aggregation. These results further suggest that in unit gravity, fluid flows and sedimentation can significantly perturb sol-gel substructures prior to gelation and these deleterious perturbations may be "frozen" into the resulting microstructure. Hence, sol-gel pores may be expected to be smaller, more uniform, and less rough when formed in microgravity.

Sol-gel Technology and Advanced Electrochemical Energy Storage Materials

Science.gov (United States)

Chu, Chung-tse; Zheng, Haixing

1996-01-01

Advanced materials play an important role in the development of electrochemical energy devices such as batteries, fuel cells, and electrochemical capacitors. The sol-gel process is a versatile solution for use in the fabrication of ceramic materials with tailored stoichiometry, microstructure, and properties. This processing technique is particularly useful in producing porous materials with high surface area and low density, two of the most desirable characteristics for electrode materials. In addition,the porous surface of gels can be modified chemically to create tailored surface properties, and inorganic/organic micro-composites can be prepared for improved material performance device fabrication. Applications of several sol-gel derived electrode materials in different energy storage devices are illustrated in this paper. V2O5 gels are shown to be a promising cathode material for solid state lithium batteries. Carbon aerogels, amorphous RuO2 gels and sol-gel derived hafnium compounds have been studied as electrode materials for high energy density and high power density electrochemical capacitors.

Sol-Gel Derived, Nanostructured Oxide Lubricant Coatings

National Research Council Canada - National Science Library

Taylor, Douglas

2000-01-01

In this program, we deposited oxide coatings of titanium and nickel by wet-chemical deposition methods, also referred to as sol-gel, which showed excellent tribological properties in previous investigations...

Foliar application of two silica sols reduced cadmium accumulation in rice grains

International Nuclear Information System (INIS)

Liu Chuanping; Li Fangbai; Luo Chunling; Liu Xinming; Wang Shihua; Liu Tongxu; Li Xiangdong

2009-01-01

In the present study, pot experiments were conducted to investigate the effects of foliar application of two silica (Si) sols on the alleviation of cadmium (Cd) toxicity in contaminated soil to rice. Results showed that the foliar application of Si sols significantly increased the dry weight of grains (without husk) and shoots in rice grown in Cd contaminated soil, whereas the Cd concentration in the grains and shoots decreased obviously. The total accumulation of Cd in rice grains also decreased with the application of both of the Si sols, but no significant effect was found on the Cd accumulation in the shoots. For the optimal effect, Si-sol-B should be foliar applied at the tillering-stage during rice growth. The mechanism of Si foliar application to alleviate the toxicity and accumulation of Cd in grains of rice may be related to the probable Cd sequestration in the shoot cell walls

Efficacy of a new tan doped sol-gel sorbent for uptake of zinc

International Nuclear Information System (INIS)

Khan, A.; Ahmed, S.; Riaz, M.; Mahmood, F.; Younas Khokhar, M.

2003-01-01

A TAN (1-(2-Thiazolylazo)-2-naphthol) doped sol gel silica sorbent (reddish colour, porous, stable, hard, non-swelling) were prepared and investigated for the removal of Zn (II) from aqueous solutions. The kinetics, adsorption isotherm, equilibration time and pH effect on the removal were studied from non competitive aqueous solution to optimize the conditions to be utilized on a large scale. Fast equilibration was observed and adsorption equilibria were reached within 30 minutes. Adsorption of zinc ions on the blank (un-doped) sol gel was found negligible. The maximum adsorption of Zn (II) ions onto the TAN doped sol-gel from single solutions were 2.33 mg/g (0.035 mmol/g). TAN doped sol gel can be regenerated through washing with a solution of 0.1 M HCl solution. The maximum regeneration value was as high as 99.0%. The TAN-doped sol gel silica is suitable at least for four adsorption-desorption cycles without experiencing considerable loss of adsorption capacity. The uptake route and the nature of the Zn-TAN complex have been discussed. (orig.)

The conversion of the thermal energy of plasma in the SOL of tokamaks

International Nuclear Information System (INIS)

Nedospasov, A.V.; Nenova, N.V.

2008-01-01

When the plasma expands across the confining magnetic field, a part of its thermal energy is converted to electrical energy. In the SOL of tokamaks, the motion of the plasma across the field due to turbulent processes is accompanied by its departure along the open lines of the magnetic field. The conversion of thermal energy is taken into account in theoretical studies devoted to the physics of plasma in the SOL; however, this conversion is ignored in numerical models, for example, in B2-SOLPS4.0. This paper deals with thermal-to-electrical energy conversion in the SOL of tokamaks. It is demonstrated that the part of the thermal energy subjected to conversion to electrical energy forms an appreciable part of the total energy flowing in the SOL. In ITER, this fraction may be as high as 20-25%. The electrical energy generated in the SOL volume is liberated in the form of Joule heat in a relatively cold plasma in the vicinity of diverter plates or directly on these plates. (letter)

Nanostructured sol-gel coatings doped with cerium nitrate as pre-treatments for AA2024-T3

International Nuclear Information System (INIS)

Zheludkevich, M.L.; Serra, R.; Montemor, M.F.; Yasakau, K.A.; Salvado, I.M. Miranda; Ferreira, M.G.S.

2005-01-01

Nanostructured hybrid sol-gel coatings doped with cerium ions were investigated in the present work as pre-treatments for the AA2024-T3 alloy. The sol-gel films have been synthesized from tetraethylorthosilicate (TEOS) and 3-glycidoxypropyltrimethoxysilane (GPTMS) precursors. Additionally the hybrid sol was doped with zirconia nanoparticles prepared from hydrolyzed tetra-n-propoxyzirconium (TPOZ). Cerium nitrate, as corrosion inhibitor, was added into the hybrid matrix or into the oxide nanoparticles. The chemical composition and the structure of the hybrid sol-gel films were studied by XPS (X-ray photoelectron spectroscopy) and AFM (atomic force microscopy), respectively. The evolution of the corrosion protection properties of the sol-gel films was studied by EIS (electrochemical impedance spectroscopy), which can provide quantitative information on the role of the different pre-treatments. Different equivalent circuits, for different stages of the corrosion processes, were used in order to model the coating degradation. The models were supported by SEM (scanning electron microscopy) measurements. The results show that the sol-gel films containing zirconia nanoparticles present improved barrier properties. Doping the hybrid nanostructured sol-gel coatings with cerium nitrate leads to additional improvement of the corrosion protection. The zirconia particles present in the sol-gel matrix seem to act as nanoreservoirs providing a prolonged release of cerium ions. The nanostructured sol-gel films doped with cerium nitrate can be proposed as a potential candidate for substitution of the chromate pre-treatments for AA2024-T3

Functionalization of sol-gel zirconia composites with europium complexes

International Nuclear Information System (INIS)

Danchova, Nina; Gutzov, Stoyan

2014-01-01

Different sol-gel strategies based on functionalization of ZrO 2 :Eu microparticles with 1,10-phenanthroline (phen) and incorporation of colloidal Eu(phen) 2 (NO 3 ) 3 into zirconia have been used to obtain hybrid sol-gel composites with controlled optical properties. The process leads to materials with quantum yields of about 48 % monitoring the 615 nm emission line at 350 nm excitation. Excitation/luminescence spectroscopy, diffuse reflectance spectroscopy and X-ray diffraction have been used to characterize the hybrid zirconia composites. (orig.)

Third Order Susceptibility of Platinum Sulfide Sol

National Research Council Canada - National Science Library

LaiHing, Kenneth

1992-01-01

.... Experimentally this is determined using degenerate four-wave mixing (DFWM). Pure sulfur sol was prepared by dissolving the solid sulfur in hydrazine, followed by addition of distilled water with vigorous stirring...

utilisation des donnees pour l'evaluation de l'heterogeneite des sols

African Journals Online (AJOL)

AISA

étude a permis de caractériser l'hétérogénéité des sols ferrallitiques, à travers sa couleur. Mots-clés : Couleur ... ainsi qu'à l'application des recommandations des doses de fertilisant. ..... de « système sol » en zone de contact forêt- savane du ...

Opportunity's View After Drive on Sol 1806 (Stereo)

Science.gov (United States)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11816 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11816 NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo, full-circle view of the rover's surroundings just after driving 60.86 meters (200 feet) on the 1,806th Martian day, or sol, of Opportunity's surface mission (Feb. 21, 2009). North is at the center; south at both ends. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. Tracks from the drive extend northward across dark-toned sand ripples and light-toned patches of exposed bedrock in the Meridiani Planum region of Mars. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). Engineers designed the Sol 1806 drive to be driven backwards as a strategy to redistribute lubricant in the rovers wheels. The right-front wheel had been showing signs of increased friction. The rover's position after the Sol 1806 drive was about 2 kilometer (1.2 miles) south southwest of Victoria Crater. Cumulative odometry was 14.74 kilometers (9.16 miles) since landing in January 2004, including 2.96 kilometers (1.84 miles) since climbing out of Victoria Crater on the west side of the crater on Sol 1634 (August 28, 2008). This view is presented as a cylindrical-perspective projection with geometric seam correction.

Sílica solúvel em solos Soluble silica in soils

Directory of Open Access Journals (Sweden)

Bernardo van Raij

1973-01-01

Full Text Available Determinou-se a silica solúvel nos horizontes superficial e B2 de 44 perfis de solos do Estado de São Paulo. A extração da silica com solução 0,0025M de cloreto de cálcio evitou a dispersão dos solos e forneceu resultados em média apenas 8% menores do que a silica solúvel em água. Os resultados variaram de 2,2 a 92,2 ppm de SiO2. Verificou-se que, para solos com teores semelhantes de argila, os teores de silica solúvel foram maiores para solos com horizonte B textural, quando comparados com solos de horizonte B latossólico. Dentro dos agrupamentos de solos com horizonte B textural e horizonte B latossólico, os teores de silica solúvel foram maiores para os solos mais argilosos. Não foi observada relação entre silica solúvel e o pH dos solos.The extraction of soluble silica of soils with 0.0025M calcium chloride solution avoided dispersion of clay and results were on the average only 8% lower than water soluble silica. The results for surface and B2 horizons of 44 soil profiles of the State of São Paulo varied between 2.2 and 92.9 ppm of SiO2. For soils with similar clay contents, soluble silica was higher for soil with argillic B horizons as compared with soils with oxic B horizons. Within each group of soils, higher soluble silica results were associated with higher clay contents. Soluble silica apparently was not related to soil pH.

SOL-Gel microspheres and nanospheres for controlled release applications

International Nuclear Information System (INIS)

Barbe, C.; Beyer, R.; Kong, L.; Blackford, M.; Trautman, R.; Bartlett, J.

2002-01-01

We present a novel approach to the synthesis of inorganic sol-gel microspheres for encapsulating organic and bioactive molecules, and controlling their subsequent release kinetics. The bioactive species are incorporated, at ambient temperature, into the inorganic particles using an emulsion gelation process. Independent control of the release rate (by adapting the nanostructure of the internal pore network to the physico-chemical properties of the bioactive molecules) and particle size (by tailoring the emulsion chemistry) is demonstrated. Sol-gel chemistry has been shown to be a flexible technique for producing inorganic silica matrices with tailored microstructures, which can be used for the encapsulation and controlled release of organic and bioactive molecules. The present paper extends this concept by combining sol-gel chemistry with an emulsion approach for producing inorganic particles with controlled dimensions, and demonstrates how the particle size and microstructure can be independently controlled. Sol-Gel Chemistry and Encapsulation of Model Compounds. A stock solution of 4-(2-hydroxy-l-naphthylazo) benzene sulfonic acid (Orange II) was produced by dissolving Orange II in water (0.1 wt%), and adjusting the pH to the required value. Sol-gel solutions were subsequently prepared by mixing the aqueous solution with tetramethylorthosilicate (TMOS) and methanol (MeOH), to achieve H 2 O:TMOS (W] and MeOH:TMOS mole ratios (D) of four. The resulting solution was stirred and left to age at ambient temperature for one day. A transparent emulsion was prepared by mixing selected surfactants and organic solvents. The surfactants used included sorbitan monooleate, sorbitan monolaurate and bis-2-ethylhexylsulfo-succinate (AOT), while the organic phase was typically chosen from the group consisting of kerosene, hexane, heptane, octane, decane, dodecane and cyclohexane. The sol-gel solution was added to the emulsion, and the resulting mixture was stirred at 500 rpm for

Minimally Adhesive, Advanced Non-toxic Coatings of Dendrimeric Catalysts in Sol-Gel Matrices

Science.gov (United States)

2015-10-19

Catalysts in Sol -Gel Matrices 5a. CONTRACT NUMBER 5b. GRANT NUMBER N00014-09-1-0217 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Detty, Michael R. 5d...Technical Report for ONR N00014-09-1-0217 Minimally Adhesive, Advanced Non-toxic Coatings of Dendrimeric Catalysts in Sol -Gel Matrices Michael R. Detty, PI...Environmentally benign sol -gel antifouling and foul-releasing coatings. Ace. Chem. Res. 2014, 47, 678-687. 11) Alberto, E. E.; Müller, L. M

PON-Sol: prediction of effects of amino acid substitutions on protein solubility.

Science.gov (United States)

Yang, Yang; Niroula, Abhishek; Shen, Bairong; Vihinen, Mauno

2016-07-01

Solubility is one of the fundamental protein properties. It is of great interest because of its relevance to protein expression. Reduced solubility and protein aggregation are also associated with many diseases. We collected from literature the largest experimentally verified solubility affecting amino acid substitution (AAS) dataset and used it to train a predictor called PON-Sol. The predictor can distinguish both solubility decreasing and increasing variants from those not affecting solubility. PON-Sol has normalized correct prediction ratio of 0.491 on cross-validation and 0.432 for independent test set. The performance of the method was compared both to solubility and aggregation predictors and found to be superior. PON-Sol can be used for the prediction of effects of disease-related substitutions, effects on heterologous recombinant protein expression and enhanced crystallizability. One application is to investigate effects of all possible AASs in a protein to aid protein engineering. PON-Sol is freely available at http://structure.bmc.lu.se/PON-Sol The training and test data are available at http://structure.bmc.lu.se/VariBench/ponsol.php mauno.vihinen@med.lu.se Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Functionalizable Sol-Gel Silica Coatings for Corrosion Mitigation

Directory of Open Access Journals (Sweden)

Jolanta Gąsiorek

2018-01-01

Full Text Available Corrosion is constantly a major problem of the world economy in the field of metal products, metal processing and other areas that utilise metals. Previously used compounds utilizing hexavalent chromium were amongst the most effective materials for corrosion protection but regulations have been recently introduced that forbid their use. Consequently, there is a huge drive by engineers, technologists and scientists from different disciplines focused on searching a new, more effective and environmentally-friendly means of corrosion protection. One novel group of materials with the potential to solve metal protection problems are sol-gel thin films, which are increasingly interesting as mitigation corrosion barriers. These environmentally-friendly and easy-to-obtain coatings have the promise to be an effective alternative to hexavalent chromium compounds using for anti-corrosion industrial coatings. In this review the authors present a range of different solutions for slow down the corrosion processes of metallic substrates by using the oxides and doped oxides obtained by the sol-gel method. Examples of techniques used to the sol-gel coating examinations, in terms of anti-corrosion protection, are also presented.

Hydrogen permeation through sol-gel-coated iron during galvanostatic charging

International Nuclear Information System (INIS)

Zakorchemna, I.; Carmona, N.; Zakroczymski, T.

2008-01-01

One-layer sol-gel silica-zirconia and two-layer silica-zirconia and zirconia coatings were deposited on one side of iron membranes by spin-coating, densified in air and annealed up to 800 deg. C in vacuum. Hydrogen permeation through the membranes, coated and uncoated, polarised cathodically under galvanostatic control in 0.1 M NaOH solution was studied using the electrochemical permeation technique. During the initial period, the effect of the sol-gel coatings was insignificant. However, the coatings quite efficiently prevented the iron surface become more active to hydrogen entry during a long-lasting cathodic polarisation. In addition, the electrochemical-corrosion behaviour of the coated iron and the effect of the sol-gel coatings on the effective diffusivity of hydrogen in the coated membranes were studied. On the basis of the polarisation curves and the hydrogen permeation data it was proved that the sol-gel coatings blocked the iron surface for the hydrogen evolution reaction and, consequently, for the hydrogen entry into iron. The effective coating coverage was determined by comparison of the hydrogen fluxes permeating the coated and uncoated membranes. Finally the real concentration of hydrogen beneath the uncoated iron sites and the amount of hydrogen stored in a membrane were evaluated

Critical ageing and chemistry of nanocrystalline hydroxyapatite sol-gel solutions

Energy Technology Data Exchange (ETDEWEB)

Chai, C.S.; Gross, K.A.; Kannangara, K.; Ben-Nissan, B. [University of Technology, Sydney, NSW (Australia). Department of Chemistry, Materials and Forensic Sciences; Hanley, L. [University of Illinois at Chicago, (United States). Department of Chemistry

1998-12-31

In previous work we have demonstrated that using alkoxide precursors, it is possible to produce crystalline hydroxyapatite coatings with potential uses in orthopaedic and dental applications. However, to produce monophasic hydroxyapatite coatings, sols must be aged for a minimum of 24 hours prior to deposition. {sup 31}P NMR has been used to analyse chemical changes occurring in the sol during the ageing process and have revealed that P-O-C bonds present in the precursor material are gradually replaced by P-O-Ca bonds with an accompanying change in oxidation state from P(III) to P(V). Thermal analysis was used to examine hydrolysed gels and showed that sols aged less than 24 hours contain unreacted calcium diethoxide which produces CaO upon heating. These findings have been confirmed by x-ray diffraction. Copyright (1998) Australasian Ceramic Society 16 refs., 4 figs.

Recent progress towards a quantitative description of filamentary SOL transport

DEFF Research Database (Denmark)

Carralero, D.; Siccinio, M.; Komm, M.

2017-01-01

A summary of recent results on filamentary transport, mostly obtained with the ASDEX-Upgrade tokamak (AUG), is presented and discussed in an attempt to produce a coherent picture of scrape-off layer (SOL) filamentary transport. A clear correlation is found between L-mode density shoulder formation...... in the outer midplane and a transition between the sheath-limited and the inertial filamentary regimes. Divertor collisionality is found to be the parameter triggering the transition. A clear reduction of the ion temperature takes place in the far SOL after the transition, both for the background......-mode plasmas, although a secondary threshold related to deuterium fueling is observed. EMC3-EIRENE simulations of neutral dynamics show that an ionization front near the main chamber wall is formed after the shoulder formation. Finally, a clear increase of SOL opacity to neutrals is observed, associated...

Critical ageing and chemistry of nanocrystalline hydroxyapatite sol-gel solutions

International Nuclear Information System (INIS)

Chai, C.S.; Gross, K.A.; Kannangara, K.; Ben-Nissan, B.; Hanley, L.

1998-01-01

In previous work we have demonstrated that using alkoxide precursors, it is possible to produce crystalline hydroxyapatite coatings with potential uses in orthopaedic and dental applications. However, to produce monophasic hydroxyapatite coatings, sols must be aged for a minimum of 24 hours prior to deposition. 31 P NMR has been used to analyse chemical changes occurring in the sol during the ageing process and have revealed that P-O-C bonds present in the precursor material are gradually replaced by P-O-Ca bonds with an accompanying change in oxidation state from P(III) to P(V). Thermal analysis was used to examine hydrolysed gels and showed that sols aged less than 24 hours contain unreacted calcium diethoxide which produces CaO upon heating. These findings have been confirmed by x-ray diffraction. Copyright (1998) Australasian Ceramic Society

Laser sintering of doped strontium aluminate via modified sol-gel for use as a ceramic pigment

International Nuclear Information System (INIS)

Soares, F.M. dos S.; Valerio, M.E.G.

2017-01-01

Powder of Dy"3"+ co-doped SrAl_2O_4 :Eu"3"+ was produced via proteic sol-gel method, a modified sol-gel route which allows the formation of oxides at lower temperatures than other methods. CO_2 laser sintering was used as a method for heat treatment, effective in reducing trivalent europium ions in doped samples. Thermal analysis of the precursors, performed by TG and DTA, revealed that the crystallization of SrAl_2O_4 phase occurred at approximately 1060 °C. X-ray diffraction showed that the samples, before and after sintering, had monoclinic and hexagonal phases formation. DLS technique revealed the presence of nanosized and micrometric particles, and particle agglomerates, confirmed by SEM images. Micrographs of the fracture surface of a sintered pellet revealed a high degree of densification caused by heat treatment. Photoluminescence measurements showed that the samples after synthesis and before heat treatment with laser had reddish emission, composed of characteristic narrow emission lines from Eu"3"+ and more intense emission when the samples were excited at 265 nm. The laser treatment promoted the reduction of Eu"3"+ to Eu"2"+ and this effect was confirmed by the presence of a wide emission band in the green region of the spectrum with a maximum emission obtained after excitation at 350 nm. The luminescent decay time of the thermally treated sample was approximately 100 min. Via XRF measurements of acquired frit and DTA and TG of the frit, pigment and mixtures of both, it was noticed good compatibility in terms of thermal processes, that indicated that the pigment has a potential to be used in ceramic tiles. (author)

Tantala-based sol-gel coating for capillary microextraction on-line coupled to high-performance liquid chromatography.

Science.gov (United States)

Tran, MinhPhuong; Turner, Erica B; Segro, Scott S; Fang, Li; Seyyal, Emre; Malik, Abdul

2017-11-03

A sol-gel organic-inorganic hybrid sorbent, consisting of chemically integrated tantalum (V) ethoxide (TaEO) and polypropylene glycol methacrylate (PPGM), was developed for capillary microextraction (CME). The sol-gel sorbent was synthesized within a fused silica capillary through hydrolytic polycondensation of TaEO and chemical incorporation of PPGM into the evolving sol-gel tantala network. A part of the organic-inorganic hybrid sol-gel network evolving in the vicinity of the capillary walls had favorable conditions to get chemically bonded to the silanol groups on the capillary surface forming a surface-bonded coating. The newly developed sol-gel sorbent was employed to isolate and enrich a variety of analytes from aqueous samples for on-line analysis by high-performance liquid chromatography (HPLC) equipped with a UV detector. CME was performed on aqueous samples containing trace concentrations of analytes representing polycyclic aromatic hydrocarbons, ketones, alcohols, amines, nucleosides, and nucleotides. This sol-gel hybrid coating provided efficient extraction with CME-HPLC detection limits ranging from 4.41pM to 28.19 pM. Due to direct chemical bonding between the sol-gel sorbent coating and the fused silica capillary inner surface, this sol-gel sorbent exhibited enhanced solvent stability. The sol-gel tantala-based sorbent also exhibited excellent pH stability over a wide pH range (pH 0-pH 14). Furthermore, it displayed great performance reproducibility in CME-HPLC providing run-to-run HPLC peak area relative standard deviation (RSD) values between 0.23% and 3.83%. The capillary-to-capillary RSD (n=3), characterizing capillary preparation method reproducibility, ranged from 0.24% to 4.11%. The results show great performance consistency and application potential for the sol-gel tantala-PPGM sorbent in various fields including biomedical, pharmaceutical, and environmental areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Opportunity's Surroundings After Sol 1820 Drive (Polar)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009). This view is presented as a polar projection with geometric seam correction. North is at the top. The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock.

Opportunity's Surroundings After Sol 1820 Drive (Vertical)

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,820th to 1,822nd Martian days, or sols, of Opportunity's surface mission (March 7 to 9, 2009). This view is presented as a vertical projection with geometric seam correction. North is at the top. The rover had driven 20.6 meters toward the northwest on Sol 1820 before beginning to take the frames in this view. Tracks from that drive recede southwestward. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and small exposures of lighter-toned bedrock.

Sol-gel precursors and products thereof

Science.gov (United States)

Warren, Scott C.; DiSalvo, Jr., Francis J.; Weisner, Ulrich B.

2017-02-14

The present invention provides a generalizable single-source sol-gel precursor capable of introducing a wide range of functionalities to metal oxides such as silica. The sol-gel precursor facilitates a one-molecule, one-step approach to the synthesis of metal-silica hybrids with combinations of biological, catalytic, magnetic, and optical functionalities. The single-source precursor also provides a flexible route for simultaneously incorporating functional species of many different types. The ligands employed for functionalizing the metal oxides are derived from a library of amino acids, hydroxy acids, or peptides and a silicon alkoxide, allowing many biological functionalities to be built into silica hybrids. The ligands can coordinate with a wide range of metals via a carboxylic acid, thereby allowing direct incorporation of inorganic functionalities from across the periodic table. Using the single-source precursor a wide range of functionalized nanostructures such as monolith structures, mesostructures, multiple metal gradient mesostructures and Stober-type nanoparticles can be synthesized. ##STR00001##

Radiation hardening of sol gel-derived silica fiber preforms through fictive temperature reduction.

Science.gov (United States)

Hari Babu, B; Lancry, Matthieu; Ollier, Nadege; El Hamzaoui, Hicham; Bouazaoui, Mohamed; Poumellec, Bertrand

2016-09-20

The impact of fictive temperature (Tf) on the evolution of point defects and optical attenuation in non-doped and Er3+-doped sol-gel silica glasses was studied and compared to Suprasil F300 and Infrasil 301 glasses before and after γ-irradiation. To this aim, sol-gel optical fiber preforms have been fabricated by the densification of erbium salt-soaked nanoporous silica xerogels through the polymeric sol-gel technique. These γ-irradiated fiber preforms have been characterized by FTIR, UV-vis-NIR absorption spectroscopy, electron paramagnetic resonance, and photoluminescence measurements. We showed that a decrease in the glass fictive temperature leads to a decrease in the glass disorder and strained bonds. This mainly results in a lower defect generation rate and thus less radiation-induced attenuation in the UV-vis range. Furthermore, it was found that γ-radiation "hardness" is higher in Er3+-doped sol-gel silica compared to un-doped sol-gel silica and standard synthetic silica glasses. The present work demonstrates an effective strategy to improve the radiation resistance of optical fiber preforms and glasses through glass fictive temperature reduction.

Synthesis of Hollow Sphere and 1D Structural Materials by Sol-Gel Process.

Science.gov (United States)

Li, Fa-Liang; Zhang, Hai-Jun

2017-08-25

The sol-gel method is a simple and facile wet chemical process for fabricating advanced materials with high homogeneity, high purity, and excellent chemical reactivity at a relatively low temperature. By adjusting the processing parameters, the sol-gel technique can be used to prepare hollow sphere and 1D structural materials that exhibit a wide application in the fields of catalyst, drug or gene carriers, photoactive, sensors and Li-ion batteries. This feature article reviewed the development of the preparation of hollow sphere and 1D structural materials using the sol-gel method. The effects of calcination temperature, soaking time, pH value, surfactant, etc., on the preparation of hollow sphere and 1D structural materials were summarized, and their formation mechanisms were generalized. Finally, possible future research directions of the sol-gel technique were outlined.

Microstructural characterization of Al{sub 2}O{sub 3}: Eu with dosimetric purposes; Cracterizacion microestructural de Al{sub 2}O{sub 3}: Eu con fines dosimetricos

Energy Technology Data Exchange (ETDEWEB)

Mendoza A, D.; Espinosa P, M.E.; Gonzalez M, P.R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Rubio, E. [BUAP, Facultad de Ingenieria Quimica, 72570 Puebla (Mexico)

2004-07-01

In this work a microstructural analysis is presented, through Sem, EDS and XRD, of the alumina with Europium (Al{sub 2}O{sub 3}: Eu) synthesized by the sol gel method. According to those obtained results, a previous thermal treatment to 1000 C to the samples, induces the formation of the {gamma}-alumina phase for the samples that does not contain Eu; however when there is presence of this element, the {theta} alumina phase is obtained. Likewise, it was observed that the particle size is increased with the presence of Eu. When analyzing the thermoluminescent response (TL) induced by the gamma radiation, it was observed that the pure Al{sub 2}O{sub 3} presents an intense TL sign; while the Al{sub 2}O{sub 3}: Eu, the sign suffers a marked decrement. (Author)

LES RELATIONS ENTRE L’ERODABILITE DES SOLS ET LEURS PROPRIETES PHYSICO-MECANIQUES

Directory of Open Access Journals (Sweden)

I. C. Stanga

2005-10-01

Full Text Available L’érodabilité représente la susceptibilité des sols d’être érodés sous l’action des pluies, du ruissellement ou du vent. Cette susceptibilité est conditionnée par les propriétés physico-chimiques des sols. Dans l’article ci-dessous, on montre les relations qui existent entre l’érodabilité et les propriétés physico-mécaniques des sols, dont les plus importantes sont la granulométrie (surtout le rapport entre différentes fractions texturales, la structure, la densité, la permeabilité et la conductivité hydrauliques.

Thermodynamic analysis of sol-gel transition of gelatin in terms of water activity in various solutions.

Science.gov (United States)

Miyawaki, Osato; Omote, Chiaki; Matsuhira, Keiko

2015-12-01

Sol-gel transition of gelatin was analyzed as a multisite stoichiometric reaction of a gelatin molecule with water and solute molecules. The equilibrium sol-gel transition temperature, Tt , was estimated from the average of gelation and melting temperature measured by differential scanning calorimetry. From Tt and the melting enthalpy, ΔHsol , the equilibrium sol-to-gel ratio was estimated by the van't Hoff equation. The reciprocal form of the Wyman-Tanford equation, which describes the sol-to-gel ratio as a function of water activity, was successfully applied to obtain a good linear relationship. From this analysis, the role of water activity on the sol-gel transition of gelatin was clearly explained and the contributions of hydration and solute binding to gelatin molecules were separately discussed in sol-gel transition. The general solution for the free energy for gel-stabilization in various solutions was obtained as a simple function of solute concentration. © 2015 Wiley Periodicals, Inc.

Dynamics Research on the Gelling Course of Silica Sol

Institute of Scientific and Technical Information of China (English)

LUYi－chun; LIZai－geng

1995-01-01

Dreipping electrolytes into silica sol ,gelling reaction will occur,The research indicates:this is a complicated physicemistry course,which consists of a pre-reaction and a polymerizaion,The former controls the whole course,and in which electronic layers of the sol's particles be-come more and more thiner,but with incresing of the sol concentration,its control force will be diminished ,till the fast-coagulation ,the gelling couse becomes o-controlled,The latter is an in-finite polymeric chani-reaction.The result of gelatination is to produce a very big plymeric molecule-gel,which involves in all space,includes all water ,and its molecular weight is in-definite big.The researh also indicates:the dy-namic course of the gelling could be described quantitaively by an experience formula:lgt=-nlgc+B,All of the characteristic values have definite physical meaning,Electronic value of the contrary-inos is the biggest influential factor ,the natures of the contrary-ions and the natures of the same-electronic-inos have a few influential forces on the characteristic values,The temperature increasing makes the gelling reaction fast.

Sol-gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain.

Science.gov (United States)

Madani, Azamsadat; Nakhaei, Mohammadreza; Karami, Parisa; Rajabzadeh, Ghadir; Salehi, Sahar; Bagheri, Hossein

2016-01-01

The aim of this in vitro study was to evaluate the effect of silica and aluminosilicate nanocomposite coating of zirconia-based dental ceramic by a sol-gel dip-coating technique on the bond strength of veneering porcelain to the yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in vitro. Thirty Y-TZP blocks (10 mm ×10 mm ×3 mm) were prepared and were assigned to four experimental groups (n=10/group): C, without any further surface treatment as the control group; S, sandblasted using 110 μm alumina powder; Si, silica sol dip coating + calcination; and Si/Al, aluminosilicate sol dip coating + calcination. After preparing Y-TZP samples, a 3 mm thick layer of the recommended porcelain was fired on the coated Y-TZP surface. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis were used to characterize the coating and the nature of the bonding between the coating and zirconia. To examine the zirconia-porcelain bond strength, a microtensile bond strength (μTBS) approach was chosen. FT-IR study showed the formation of silica and aluminosilicate materials. XRD pattern showed the formation of new phases consisting of Si, Al, and Zr in coated samples. SEM showed the formation of a uniform coating on Y-TZP samples. Maximum μTBS values were obtained in aluminosilicate samples, which were significantly increased compared to control and sandblasted groups (P=0.013 and Pcoating can be considered as a convenient, less expensive reliable method for improving the bond strength between dental Y-TZP ceramics and veneering porcelain.

Magnetic field dependence observed by 27 Al NMR of species contained in alumina colloidal dispersions

International Nuclear Information System (INIS)

Morgado Junior, Edisson; Menezes, Sonia M.C.; San Gil, Rosane

1995-01-01

The behaviour of some aluminium species front a magnetic field have been investigated by 27 Al NMR analysis, this method was used for characterization of an octahedric aluminium specie from sols prepared by bohemite acid peptization. X-ray diffraction data have identified the mineral structure. The results have been shown and discussed, and NMR spectra were also presented and studied. Concluding this work, the nature of a colloidal specie of alumina was clarified through the dependence research of magnetic field by 27 Al NMR

Synthesis of hybrid chitosan/calcium aluminosilicate using a sol-gel method for optical applications

Energy Technology Data Exchange (ETDEWEB)

Elnahrawy, Amany Mohamed [Department of Solid State, Physics Division, National Research Center (NRC), Giza 12622, Cairo (Egypt); Kim, Yong Soo, E-mail: yskim2@ulsan.ac.kr [Department of Physics and Energy Harvest-Storage Research Center (EHSRC), University of Ulsan, Ulsan 44610 (Korea, Republic of); Ali, Ahmed I., E-mail: Ahmed_ali_2010@helwan.edu.eg [Department of Physics and Energy Harvest-Storage Research Center (EHSRC), University of Ulsan, Ulsan 44610 (Korea, Republic of); Basic Science Department, Faculty of Industrial Education & Technology, Helwan University, Cairo 11281 (Egypt)

2016-08-15

Hybrid chitosan (CS)/calcium aluminosilicate nanocomposites thin films and membranes were prepared using a sol–gel method with three different concentrations of Al{sub 2}O{sub 3} (5, 7 and 10 mol. %). The prepared nanocomposites were characterized by transmission electron microscopy, X-ray diffraction and Fourier Transform Infrared spectroscopy. The optical properties of the prepared samples were analyzed by UV/Vis spectrophotometry and photoluminescence (PL) spectroscopy. The optical parameters revealed an increase in both the refractive index and band gap of the nanocomposites with increasing Al concentration. In addition, the PL spectra revealed a blue shift that was consistent with an increase in the optical band gap. These results suggest that CS/calcium aluminosilicate in two different forms can be a good candidate for optical sensors applications. - Highlights: • We show a large specific surface area of hybrid CS/calcium aluminosilicate thin films and membranes using sol-gel method. • Inorganic SiO{sub 2}-based phase are perfectly embedded onto chitosan matrix has a reliable stability. • CS/calcium aluminosilicate could be usable for optical sensors, planar waveguide, and bio-sensing.

Etat Du Magnesium Dans Quelques Sols Sales Du Sud Et Du ...

African Journals Online (AJOL)

étude a été réalisée sur 86 échantillons de sols provenant du Centre et du Sud de l´Irak. L\\'expérimentation a consisté, d´une part, à calculer les différents sels dominants dans les sols salés par la méthode de combinaison hypothétique et, ...

Physical properties and heterojunction device demonstration of aluminum-doped ZnO thin films synthesized at room ambient via sol-gel method

Energy Technology Data Exchange (ETDEWEB)

Karaagac, Hakan, E-mail: hkaraagac@ucdavis.edu [Department of Electrical and Computer Engineering, University of California at Davis, Davis, CA 95616 (United States); Yengel, Emre; Saif Islam, M. [Department of Electrical and Computer Engineering, University of California at Davis, Davis, CA 95616 (United States)

2012-04-25

Highlights: Black-Right-Pointing-Pointer Undoped and Al doped ZnO (AZO) thin films were successfully prepared using sol-gel technique. Black-Right-Pointing-Pointer Structural analysis has revealed that Al doping has a significant influence on preferential orientation. Black-Right-Pointing-Pointer It has been observed that wrinkles forms on the surface of films when annealed with a fast heat ramp up rate. Black-Right-Pointing-Pointer Optical analysis has revealed that that the band gap energy of ZnO thin film increases with increasing Al doping concentration. Black-Right-Pointing-Pointer The lowest resistivity is observed for 1% Al ZnO thin film, which is 2.2 Multiplication-Sign 10{sup -2} ({Omega} cm). - Abstract: ZnO and some of its ternary wide-bandgap alloys offer interesting opportunities for designing materials with tunable band gaps, strong piezoresistivity and controlled electrical conductance with high optical transparency. Synthesizing these materials on arbitrary substrates using low-cost and unconventional techniques can help in integrating semiconductors with different physical, electrical, and optical characteristics on a single substrate for heterogeneous integration of multifunctional devices. Here we report the successful synthesis of aluminum (Al) doped ZnO (AZO) thin films on soda-lime glass, silicon and fluorine doped tin oxide (FTO) pre-coated glass substrates by using sol-gel deposition method at ambient condition. X-ray diffraction (XRD) analysis revealed that varying degree of Al doping significantly impacts the crystal orientation, semiconductor bandgap and optical transparency of the film. Crystal structure of the film is also found to be strongly correlated to the characteristics of the substrate material. The impact of heating rate during post annealing process is studied and optimized in order to improve the surface morphology of the deposited films. Optical characterizations have revealed that bandgap energy of AZO films can be tuned

Morphology and the isoelectric point of nanosized aqueous ceria sols

International Nuclear Information System (INIS)

Gulicovski, Jelena J.; Bračko, Ines; Milonjić, Slobodan K.

2014-01-01

Ceria sols were synthesized by a forced hydrolysis method using cerium sulphate or cerium nitrate as precursors. High-resolution TEM was used to determine the microstructure and particle size of CeO 2 . A polycrystalline structure of ceria sols with crystallite sizes of 4.4 and 8.6 nm was obtained. The particles had a well-defined polyhedral shape. Direct bandgaps for ceria nanoparticles were 2.80 and 3.31 eV, respectively. The isoelectric point, pH iep , of ceria sols in KNO 3 solutions was investigated. The isoelectric point of ceria was found to be pH iep  = 7.6 ± 0.2. The obtained results indicate that the isoelectric point in the presence of SO 4 2− ions shifts to lower pH value. The particle size of ceria increases with pH, reaching the maximum value at pH iep as the result of agglomeration . - Highlights: • Ceria sols with cubic phase nanoparticles have been successfully synthesized. • The isoelectric point of ceria oxide in KNO 3 solutions was p Hiep  = 7.6 ± 0.2. • The specific adsorption of SO 4 2− ions causes a shift in IEP to lower pH (pH iep  = 6.7). • The correlation between IEP and the maximum diameter of particles was observed

Hydroxyapatite, fluor-hydroxyapatite and fluorapatite produced via the sol-gel method. Optimisation, characterisation and rheology.

Science.gov (United States)

Tredwin, Christopher J; Young, Anne M; Georgiou, George; Shin, Song-Hee; Kim, Hae-Won; Knowles, Jonathan C

2013-02-01

Currently, most titanium implant coatings are made using hydroxyapatite and a plasma spraying technique. There are however limitations associated with plasma spraying processes including poor adherence, high porosity and cost. An alternative method utilising the sol-gel technique offers many potential advantages but is currently lacking research data for this application. It was the objective of this study to characterise and optimise the production of Hydroxyapatite (HA), fluorhydroxyapatite (FHA) and fluorapatite (FA) using a sol-gel technique and assess the rheological properties of these materials. HA, FHA and FA were synthesised by a sol-gel method. Calcium nitrate and triethylphosphite were used as precursors under an ethanol-water based solution. Different amounts of ammonium fluoride (NH4F) were incorporated for the preparation of the sol-gel derived FHA and FA. Optimisation of the chemistry and subsequent characterisation of the sol-gel derived materials was carried out using X-ray Diffraction (XRD) and Differential Thermal Analysis (DTA). Rheology of the sol-gels was investigated using a viscometer and contact angle measurement. A protocol was established that allowed synthesis of HA, FHA and FA that were at least 99% phase pure. The more fluoride incorporated into the apatite structure; the lower the crystallisation temperature, the smaller the unit cell size (changes in the a-axis), the higher the viscosity and contact angle of the sol-gel derived apatite. A technique has been developed for the production of HA, FHA and FA by the sol-gel technique. Increasing fluoride substitution in the apatite structure alters the potential coating properties. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Spray pyrolysis synthesis of γ-Al_2O_3 supported metal and metal phosphide catalysts and their activity in the hydrodeoxygenation of a bio-oil model compound

International Nuclear Information System (INIS)

Ly, Hoang Vu; Im, Kyungmin; Go, Youngchae; Galiwango, Emmanuel; Kim, Seung-Soo; Kim, Jinsoo; Choi, Jae Hyung; Woo, Hee Chul

2016-01-01

Highlights: • Spherical γ-Al_2O_3 supported metal and metal phosphide catalysts were synthesized by spray pyrolysis method. • Hydrodeoxygenation (HDO) of 2-furyl methyl ketone (FMK) was conducted using metal/metal phosphide catalysts. • FMK was converted into 2-allyl furan and methyl cyclohexane. • The highest FMK conversion of 83% was achieved over 10 wt% Ni/γ-Al_2O_3 catalysts at reaction temperature of 400 °C. - Abstract: In this study, spherical γ-Al_2O_3 supported metal and metal phosphide (Ni, Co, Ni_2P and CoP) catalysts were successfully prepared by combining sol-gel and spray pyrolysis methods. First boehmite sol was prepared based on the Yoldas process and then the corresponding metal salts were added to the sol at the desired concentration, followed by spray pyrolysis of the mixed solution. As the well-mixed solution was transformed to spherical γ-Al_2O_3 supported metal and metal phosphide catalysts during spray pyrolysis process, the metal species were uniformly distributed in the mesoporous γ-Al_2O_3 supports. The product catalysts were investigated under different conditions for hydrodeoxygenation of bio-oil model compound, 2-furyl methyl ketone (FMK), which is the main component of the bio-oil product from pyrolysis of Saccharina japonica. Among the investigated catalysts, the 10 wt% Ni/γ-Al_2O_3 catalyst after calcination at 800 °C showed the highest FMK conversion of 83.02% at the reaction temperature of 400 °C. The gas and liquid products were analyzed by gas chromatography (GC) with TCD/FID detectors and GC–MS, respectively, to determine the product compositions.

Scratch resistance of SiO2 and SiO2 - ZrO2 sol-gel coatings on glass-ceramic obtained by sintering

International Nuclear Information System (INIS)

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

2013-01-01

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 2 O-Al 2 O3-SiO 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)

Sol-Gel Material-Enabled Electro-Optic Polymer Modulators

Science.gov (United States)

Himmelhuber, Roland; Norwood, Robert A.; Enami, Yasufumi; Peyghambarian, Nasser

2015-01-01

Sol-gels are an important material class, as they provide easy modification of material properties, good processability and are easy to synthesize. In general, an electro-optic (EO) modulator transforms an electrical signal into an optical signal. The incoming electrical signal is most commonly information encoded in a voltage change. This voltage change is then transformed into either a phase change or an intensity change in the light signal. The less voltage needed to drive the modulator and the lower the optical loss, the higher the link gain and, therefore, the better the performance of the modulator. In this review, we will show how sol-gels can be used to enhance the performance of electro-optic modulators by allowing for designs with low optical loss, increased poling efficiency and manipulation of the electric field used for driving the modulator. The optical loss is influenced by the propagation loss in the device, as well as the losses occurring during fiber coupling in and out of the device. In both cases, the use of sol-gel materials can be beneficial due to the wide range of available refractive indices and low optical attenuation. The influence of material properties and synthesis conditions on the device performance will be discussed. PMID:26225971

Sol-gel synthesis of lanthanum-gallate-based ceramic coatings

International Nuclear Information System (INIS)

Golubko, N.V.; Kaleva, G.M.; Roginskaya, Yu.E.; Politova, E.D.

2007-01-01

Phase-pure (La 0.9 Sr 0.1 )(Ga 0.7 Fe 0.3 )O 3-y and (Sr 1.8 La 0.2 )(GaFe)O 5.1 solid solutions with the perovskite and brownmillerite structures have been prepared from salt solutions by sol-gel processing at temperatures from 570 to 870 K. Ceramic coatings up to 100 μm in thickness have been produced by applying suspensions of the sol-gel powders to various substrates. The structure and microstructure of the ceramic coatings have been studied by X-ray diffraction and scanning electron microscopy [ru

Fiber damage during the consolidation of PVD Ti-6Al-4V coated NEXTEL 610 trademark alumina fibers

International Nuclear Information System (INIS)

Warren, J.; Elzey, D.M.; Wadley, H.N.G.

1995-01-01

Titanium matrix composites reinforced with sol-gel synthesized α-alumina fiber tows have attracted interest as a potentially low cost continuous fiber reinforced metal matrix composite system. The authors have conducted a detailed investigation of fiber damage during high temperature consolidation of PVD Ti-6Al-4V metallized sol-gel alumina fiber tows. Using both hot isostatic pressing and interrupted vacuum hot press consolidation cycles, the two principal mechanisms of fiber damage have been experimentally identified to be microbending/fracture and fiber matrix reaction. A time dependent micromechanics model incorporating the evolving geometry and mechanical properties of both the fibers and matrix has been formulated to simulate the fiber bending/failure mechanism in a representative unit cell and explore the effect of fiber strength loss due to reaction with the matrix. This model has been used to design a process cycle that minimizes damage by exploiting the enhanced superplastic deformation of the initially nanocrystalline PVD Ti-6Al-4V matrix

Novel synthesis of Prussian blue nanoparticles and nanocomposite sol: Electro-analytical application in hydrogen peroxide sensing

International Nuclear Information System (INIS)

Pandey, Prem C.; Pandey, Ashish K.

2013-01-01

Highlights: ► Novel process for the synthesis of PBNPs sol of 15.8 nm size is reported. ► The PBNPs sol shows the electron transfer rate constant to the order of 32.1 s −1 ► The PBNPs sol has shown the functional activity for making the nanocomposite. ► The nanocomposite with tris(2,2′-bipyridyl)ruthenium shows photoluminiscent ability. ► The PBNPs and its nanocomposite (PB-Rubpy) show high sensitivity for H 2 O 2 sensing. - Abstract: This paper reports a new method for the synthesis of Prussian blue nanoparticles (PBNPs) sol of homogeneous dispersion with average particle size to the order of 15.8 nm. The new method of PBNPs sol synthesis is based on the interaction of active concentrations of 3-aminopropylalkoxysilane, cyclohexanone and single precursor potassium ferricyanide under ambient conditions. The PBNPs sol shows excellent electrochemistry with electron transfer rate constant to the order of 32.1 s −1 . The resulting PBNPs sol has been found highly stable for practical applications and shows functional activity for making nanocomposite sol with tris(2,2′-bipyridyl) ruthenium (Rubpy). The PB-Rubpy nanocomposite shows high sensitivity for H 2 O 2 electrochemical sensing to the order of 1102.0 μA mM −1 cm −2 and storage stability of the materials for more than 3 months. In addition, these nanocomposite exhibits excellent electrocatalytic property for hydrogen peroxide (H 2 O 2 ) sensing with catalytic rate constant to the order of 3.14 × 10 3 M −1 s −1 . The PB-Rubpy nanocomposite sol, apart from electrocatalytic application, shows photoluminiscent ability for many opto-electroanalytical applications. In addition to that functional property of PBNPs sol for making nanodispersion with several known nanoparticles of gold, silver, palladium along with in situ synthesis of mixed metal hexacyanoferrate have also been observed.

A comparative study of planar, SPECT, x-ray CT and angiographic imaging in the detectability of space occupying lesion (SOL) of liver

International Nuclear Information System (INIS)

Manabe, Takao; Oda, Junro; Kamino, Toshio

1986-01-01

Planar, SPECT, X-CT, and angiography were compared in 47 patients with suspected SOL in the liver. SPECT had greater sensitivity and specificity in detecting SOLs than planar. Especially the detection of SOL less than 3 cm was improved, and the smallest SOL detected by SPECT was 1.0 cm in diameter. SPECT appears reliable procedure for screening SOLs in the liver. Compared with X-CT, SPECT had nearly equal sensitivity in detecting SOLs more than 3 cm, and X-CT had higher sensitivity in detecting SOLs less than 3 cm. But in some cases, for example isodensity SOL, SPECT could detect the SOL which was missed by X-CT. (author)

La lucidez es la herida mas cercana al sol

Directory of Open Access Journals (Sweden)

Juan E. Manuel Roca

2015-01-01

Full Text Available La comunicación interpersonal, muchas veces es dejada de lado por los comunicólogos, sin embargo tiene suma gravitación en las relaciones cotidianas entre las personas y en los procesos comunicacionales, toca el lenguaje de los gestos, la (in comunicación política, ceremonial y protocolo, intermediación en la comunicación, los jóvenes se incomunican. Respecto al Periodismo Investigativo señala que a pesar de los riesgos que implica el periodismo investigativo, muchos profesionales de América Latina no dudan en practicarlo, escudriñando muchas veces en temas que de no ser por ellos permanecerían ocultos. En otro artículo se habla de la importante repercusión que tuvo en América Latina el concurso CHASQUI, el que contó con la participación de profesionales de todo el continente. Incluye la entrega de entrevistas a destacados comunicadores de América Latina. Una sección está dedicada a las nuevas tecnologías: red de noticias y transmisiones vía satélite.

Produção de nanopartículas de Al2O3 utilizando água de coco maduro (coco seco Production of Al2O3 nanoparticles employing mature coconut water (dried coconut

Directory of Open Access Journals (Sweden)

V. K. S. Soares

2013-03-01

Full Text Available O presente trabalho propõe o emprego de uma nova rota de produção de nanopartículas para aplicação em indústria cerâmica. Esta rota, conhecida como rota sol-gel proteico, usualmente utiliza água de coco verde para dissolver os sais precursores, em substituição aos alcóxidos metálicos empregados no processo convencional. No entanto, não existem relatos da utilização da água de coco maduro, geralmente descartada pelas indústrias de processamento de coco, para fabricação de nanopartículas. Nanopartículas de Al2O3 foram produzidas através da rota sol-gel proteico utilizando água de coco maduro como fluido precursor molecular e foram caracterizadas por meio de análises termogravimétrica-térmica diferencial, difração de raios X, microscopia eletrônica de varredura e microscopia de força atômica. Amostras com água de coco verde também foram produzidas e usadas como referência. A fase γ-Al2O3 foi obtida após calcinação a 700 °C, permanecendo estável após calcinação a 1200 °C. Observou-se um aumento no tamanho das partículas à medida que a temperatura de calcinação aumentava, sendo os tamanhos estimados em ~ 400 nm para as amostras calcinadas a 1200 °C.The present work proposes a new preparation route of nanoparticles to be used in the ceramic industry. This new route, known as proteic sol-gel, usually employs green coconut water to dissolve the precursor salts, instead of conventional metal alcoxides. However there are no reports about the employment of water from mature coconut in the preparation of nanoparticles, which is usually disposed in the coconut processing industry. Al2O3 nanoparticles were produced via proteic sol-gel route using mature coconut water and were characterized through DTA/TG and XRD measurements and SEM and AFM images. The γ-Al2O3 phase was obtained after calcination at 700 °C, and was stable even after calcination at 1200 °C. An increase in particle size while the temperature

Magnetic field dependence observed by {sup 27} Al NMR of species contained in alumina colloidal dispersions; Dependencia de campo magnetico observada por RMN {sup 27} Al de especies presentes em dispersoes coloidais de alumina

Energy Technology Data Exchange (ETDEWEB)

Morgado Junior, Edisson; Menezes, Sonia M.C. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas; San Gil, Rosane [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica

1995-12-31

The behaviour of some aluminium species front a magnetic field have been investigated by {sup 27} Al NMR analysis, this method was used for characterization of an octahedric aluminium specie from sols prepared by bohemite acid peptization. X-ray diffraction data have identified the mineral structure. The results have been shown and discussed, and NMR spectra were also presented and studied. Concluding this work, the nature of a colloidal specie of alumina was clarified through the dependence research of magnetic field by {sup 27} Al NMR 12 refs., 4 figs., 2 tabs.

Photoconducting and photocapacitance properties of Al/p-CuNiO{sub 2}-on-p-Si isotype heterojunction photodiode

Energy Technology Data Exchange (ETDEWEB)

Elsayed, I.A. [Physics Department, College of Science and Humanitarian Studies, Salman bin Abdulaziz University (Saudi Arabia); Physics Department, Faculty of Science, Damietta University (Egypt); Çavaş, Mehmet [Department of Mechatronics, Faculty of Technology, Firat University, Elazig (Turkey); Gupta, R. [Department of Chemistry, Pittsburg State University, Pittsburg, KS 66762 (United States); Fahmy, T. [Physics Department, College of Science and Humanitarian Studies, Salman bin Abdulaziz University (Saudi Arabia); Polymer Research Group, Physics Department, Faculty of Science, Mansoura University (Egypt); Al-Ghamdi, Ahmed A. [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Yakuphanoglu, F., E-mail: fyhan@hotmail.com [Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Physics Department, Faculty of Science, Firat University, Elazig (Turkey)

2015-07-25

Highlights: • The CuNiO{sub 2} thin film was prepared by sol gel method. • The diode has a high photosensitivity value of 1.02 × 10{sup 3} under 100 mW/cm{sup 2}. • Al/p-Si/CuNiO{sub 2}/Al can used in optoelectronic device applications. - Abstract: Thin film of CuNiO{sub 2} was prepared by sol gel method to fabricate a photodiode. The surface morphology of the CuNiO{sub 2} thin film was investigated by atomic force microscopy (AFM). AFM results indicated that CuNiO{sub 2} film was formed from the nanoparticles and the average size of the nanoparticles was about 115 nm. The optical band gap of CuNiO{sub 2} film was calculated using optical data and was found to be about 2.4 eV. A photodiode having a structure of Al/p-Si/CuNiO{sub 2}/Al was prepared. The electronic parameters such as ideality factor and barrier height of the diode were determined and were obtained to be 8.23 and 0.82 eV, respectively. The interface states properties of the Al/p-Si/CuNiO{sub 2}/Al diode was performed using capacitance–voltage and conductance–voltage characteristics. The series resistance of the Al/p-Si/CuNiO{sub 2}/Al photo diode was observed to be decreasing with increasing frequency. The diode exhibited a photoconducting behavior with a high photosensitivity value of 1.02 × 10{sup 3} under 100 mW/cm{sup 2}. The obtained results indicate that Al/p-Si/CuNiO{sub 2}/Al can used in optoelectronic device applications.

Spherical LDH-Ag°-montmorillonite heterocoagulated system with a pH-dependent sol-gel structure for controlled accessibility of AgNPs immobilized on the clay lamellae.

Science.gov (United States)

Deák, Ágota; Janovák, László; Tallósy, Szabolcs Péter; Bitó, Tamás; Sebők, Dániel; Buzás, Norbert; Pálinkó, István; Dékány, Imre

2015-02-17

Aqueous suspensions of spherical ZnMgAl-layered double hydroxides [LDH(sph)] and antibacterial silver nanoparticles (AgNPs) deposited on the lamellae of montmorillonite were used for the synthesis of composites, which behave like coherent gels at low pH (≲4.5) and incoherent sols at higher pH (≳4.5). The composition of the composite was chosen as LDH(sph)/Ag°-montm. = 25:75 wt % in order to ensure a sol-gel transition that can also be characterized by viscometry. This pH-sensitive heterocoagulated system consisting of oppositely charged colloid particles was suitable for the release of antimicrobial AgNPs immobilized on the clay lamellae via a pH-controlled gel-sol transition. The heterocoagulation process was also characterized by surface charge titration measurements. Spherical LDH/Ag°-montmorillonite composite samples were identified by X-ray diffraction (XRD) measurements. The morphological properties of the composites were studied, and the presence of the heterocoagulated structure was confirmed by scanning electron microscopy (SEM). The nanoscale structure of the LDH(sph)-Ag°-montmorillonite composite obtained was also verified by small-angle X-ray scattering (SAXS), and the rheological characteristics were studied at various pH values. The viscosity and yield value of the composite decreased by an order of magnitude upon increasing the pH from 3.0 to 5.5. The sol-gel transition of the composite suspension was reversible in the previously mentioned pH range.

Sol-gel processes. January 1970-September 1989 (Citations from the NTIS data base). Report for January 1970-September 1989

International Nuclear Information System (INIS)

1989-09-01

This bibliography contains citations concerning the development and utilization of sol-gel processes and techniques. Topics include antireflective coatings, studies of sol-gel transitions, sol-gel synthesis and polymerization, sol-gel derived thin films and glasses, and sol-gel production of microspheres. Applications in nuclear waste management, nuclear-fuel manufacturing, glass optical waveguide development, and solar-energy collection are presented. (This updated bibliography contains 179 citations, 39 of which are new entries to the previous edition.)

Effect of concentrations of plasticizers on the sol-gel properties developed from alkoxides precursors

Energy Technology Data Exchange (ETDEWEB)

Kunst, Sandra Raquel; Longhi, Marielen; Zini, Lucas Pandolphi [Universidade de Caxias do Sul (CCET/UCS), Caxias do Sul, RS (Brazil). Centro de Ciências Exatas e Tecnologia; Beltrami, Lilian Vanessa Rossa; Boniatti, Rosiana; Cardoso, Henrique Ribeiro Piaggio; Vega, Maria Rita Ortega; Malfatti, Célia de Fraga, E-mail: lvrossa@yahoo.com.br [Universidade Federal do Rio Grande do Sul (LAPEC/UFRGS), Porto Alegre, RS (Brazil). Laboratorio de Pesquisa em Corrosão

2017-07-01

Coatings developed through sol-gel method is presented as an interesting replacement to chromium coating. Sol-gel method present advantages as high purity and excellent distribution of the components. The objective of this work is to synthesize and characterize a film obtained by sol-gel route. The film was prepared with 3-(trimethoxysilylpropyl) methacrylate (TMSPMA), tetraethoxysilane (TEOS) and cerium nitrate, using water and ethanol as solvents. Polyethyleneglycol (PEG) plasticizer was added at four different concentrations. The sol was characterized by techniques of viscosity, thermogravimetric analysis (TGA), X-ray diffraction (XRD) nuclear magnetic resonance spectroscopy (NMR) and Fourier transform infrared spectroscopy (FT-IR). The results showed that tetrafunctional alkoxides condensation was retarded by the plasticizer, forming a compact film. The film with 20 g.L-1 of PEG showed the best electrochemical behavior. (author)

Synthesis and characterization of the Pt/SiO2 nanocomposite by the sol-gel method

Directory of Open Access Journals (Sweden)

A. Salabat

2011-01-01

Full Text Available The silica supported platinum nanoparticles was synthesized by using the sol-gel method. The possibility of using diamminedinitro platinum (II as Pt precursor and effect of metal precursor concentration on the final Pt nanoparticle size was investigated. A stable silica sol was prepared via hydrolysis of tetraethyl orthosilicate (TEOS as a metal alcoxide and condensation reaction. Subsequently, diamminedinitro platinum (II was added to sol to form the Pt/silica sol. After drying and calcination of the sol, the Pt/SiO2 nanocpmposite has been obtained. Crystallographic information and crystalline size of the synthesized Pt/SiO2 were determined by X-ray diffraction (XRD method. Morphology of the nanoparticles and hydrogen-bonding interaction between silanol groups and amine ligands were characterized by SEM and Fourier transform infrared (FTIR spectra, respectively. Transmission Electron Microscopy (TEM was employed in evaluating the distribution and size of the platinum nanoparticles in the silica.

Preparación de microesferas mediante secado por aspersión Preparation of microspheres through spray drying

Directory of Open Access Journals (Sweden)

Orestes Darío López Hernández

2008-12-01

Full Text Available La industria farmacéutica moderna busca constantemente tecnologías para la obtención de transportadores de diferentes fármacos como citostáticos, antiinflamatorios, péptidos y hormonas, entre otros, que impliquen una reducción de su toxicidad y una liberación sostenida o controlada para lograr el efecto terapéutico con una sola dosis. Dentro de estas tecnologías se destaca el empleo de microesferas biodegradables de ácidos polilácticos como sistemas poliméricos matriciales de liberación controlada. En el presente trabajo se exponen aspectos relevantes relacionados con la tecnología de obtención de microesferas mediante secado por aspersión conocido también como Spray drying, el cual tiene como ventajas una alta eficiencia de encapsulación además de ser un método rápido, continuo, relativamente sencillo con respecto a otros existentes, y principalmente brinda la posibilidad de ser escalado hasta nivel de producción.The modern pharmaceutical Industry search constantly technologies for obtaining drugs targeting as antineoplasics, peptides and hormones, among other that imply a toxicity reduction, and sustained or controlled release to achieve the therapeutic effect with a single dose. These technologies employment of biodegradable microspheres of polylactic acids as matricial polymeric systems for controlled release. This work related aspects with the technology of microspheres obtaining by Spray drying which has as advantages, a high encapsulation efficiency, continuous method, relatively simple it offers the possibility of being scale up until production level.

SolCyc: a database hub at the Sol Genomics Network (SGN) for the manual curation of metabolic networks in Solanum and Nicotiana specific databases

Science.gov (United States)

Foerster, Hartmut; Bombarely, Aureliano; Battey, James N D; Sierro, Nicolas; Ivanov, Nikolai V; Mueller, Lukas A

2018-01-01

Abstract SolCyc is the entry portal to pathway/genome databases (PGDBs) for major species of the Solanaceae family hosted at the Sol Genomics Network. Currently, SolCyc comprises six organism-specific PGDBs for tomato, potato, pepper, petunia, tobacco and one Rubiaceae, coffee. The metabolic networks of those PGDBs have been computationally predicted by the pathologic component of the pathway tools software using the manually curated multi-domain database MetaCyc (http://www.metacyc.org/) as reference. SolCyc has been recently extended by taxon-specific databases, i.e. the family-specific SolanaCyc database, containing only curated data pertinent to species of the nightshade family, and NicotianaCyc, a genus-specific database that stores all relevant metabolic data of the Nicotiana genus. Through manual curation of the published literature, new metabolic pathways have been created in those databases, which are complemented by the continuously updated, relevant species-specific pathways from MetaCyc. At present, SolanaCyc comprises 199 pathways and 29 superpathways and NicotianaCyc accounts for 72 pathways and 13 superpathways. Curator-maintained, taxon-specific databases such as SolanaCyc and NicotianaCyc are characterized by an enrichment of data specific to these taxa and free of falsely predicted pathways. Both databases have been used to update recently created Nicotiana-specific databases for Nicotiana tabacum, Nicotiana benthamiana, Nicotiana sylvestris and Nicotiana tomentosiformis by propagating verifiable data into those PGDBs. In addition, in-depth curation of the pathways in N.tabacum has been carried out which resulted in the elimination of 156 pathways from the 569 pathways predicted by pathway tools. Together, in-depth curation of the predicted pathway network and the supplementation with curated data from taxon-specific databases has substantially improved the curation status of the species–specific N.tabacum PGDB. The implementation of this

Sol-Gel Synthesis of Phosphate-Based Glasses for Hydrophilic Enamel Applications

International Nuclear Information System (INIS)

Kim, Dae-Sung; Ryu, Bong-ki

2017-01-01

In this study, quaternary phosphate-based sol-gel derived glasses were synthesized from a P 2 O 5 -CaO-Na 2 O-TiO 2 system with a high TiO 2 content of up to 50 mol%. The sol-gel method was chosen because incorporating a high percentage of titanium into a phosphate network via traditional melt-quench methods is non-trivial. The structure and thermal properties of the obtained stabilized sol-gel glasses were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). The XRD results confirmed the amorphous nature of all of the stabilized sol–gel derived glasses. The FTIR results revealed that added TiO 2 enters the network as (TiO 6 ), which likely acts as a modifier oxide. Consequently, the number of terminal oxygen atoms increases, leading to an increase in the number of P-OH bonds. In addition, DSC results confirmed a decrease in glass transition and crystallization temperatures with increasing TiO 2 content. This is the first report of a sol-gel synthesis strategy combined with enameling to prepare glass at low processing temperatures and the first use of such a system for both hydrophilic and chemical resistance purposes.

Sol-Gel Synthesis of Phosphate-Based Glasses for Hydrophilic Enamel Applications

Energy Technology Data Exchange (ETDEWEB)

Kim, Dae-Sung; Ryu, Bong-ki [Pusan National University, Busan (Korea, Republic of)

2017-04-15

In this study, quaternary phosphate-based sol-gel derived glasses were synthesized from a P{sub 2}O{sub 5}-CaO-Na{sub 2}O-TiO{sub 2} system with a high TiO{sub 2} content of up to 50 mol%. The sol-gel method was chosen because incorporating a high percentage of titanium into a phosphate network via traditional melt-quench methods is non-trivial. The structure and thermal properties of the obtained stabilized sol-gel glasses were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). The XRD results confirmed the amorphous nature of all of the stabilized sol–gel derived glasses. The FTIR results revealed that added TiO{sub 2} enters the network as (TiO{sub 6}), which likely acts as a modifier oxide. Consequently, the number of terminal oxygen atoms increases, leading to an increase in the number of P-OH bonds. In addition, DSC results confirmed a decrease in glass transition and crystallization temperatures with increasing TiO{sub 2} content. This is the first report of a sol-gel synthesis strategy combined with enameling to prepare glass at low processing temperatures and the first use of such a system for both hydrophilic and chemical resistance purposes.

Photocatalytic Activity in CH3CN Related to the Surface Properties of TiO2 Powders Prepared by Sol-Gel Method

OpenAIRE

Bettoni, Marta; Candori, Pietro; Marmottini, Fabio; Perenze, Nicoletta; Rol, Cesare; Sebastiani, Giovanni V.; Vecchiocattivi, Franco

2009-01-01

Some TiO2 powders, prepared from titanium(IV)tetraisopropoxide by the sol-gel method and thermally treated between 100 and 1000∘C, have been characterized by X-ray powder diffraction and by nitrogen adsorption and desorption at 77 K to calculate the BET-specific surface area, from which the micropore volume and the external surface area can be derived. The photocatalytic activity (ka) of the above powders has been evaluated considering the TiO2-sensitized photo-oxidation of 4-methoxybenzyl al...

Integrated core-SOL simulations of L-mode plasma in ITER and Indian demo

International Nuclear Information System (INIS)

Wisitsorasak, Apiwat; Onjun, Thawatchai; Kanjanaput, Wittawat

2015-01-01

Core-SOL simulations are carried out using 1.5D BALDUR integrated predictive modeling code to investigate tokamak plasma in ITER and Indian DEMO reactors operating in low confinement mode (L-Mode). In each simulation, the plasma current, temperature, and density profiles in both core and SOL region are evolved self-consistency. The SOL is simulated by integrating the fluid equations, including sources, along the field lines. The solutions in SOL subsequently provide as the boundary conditions of core plasma region on low-confinement mode. The core plasma transport model is described using a combination of anomalous transport by Multi-Mode-Model version 2001 (MMM2001) and neoclassical transport calculated by NCLASS module together with the toroidal velocity based on the torque due to Neoclassical Toroidal Viscosity (NTV). In addition, a sensitivity analysis is explored by varying plasma parameters, such as plasma density and auxiliary heating power. Furthermore, the ignition tests are conducted to observed plasma response in each design after shutting down an auxiliary heating. (author)

Properties of Zn O/Cr thin films prepared by Sol-Gel

International Nuclear Information System (INIS)

Tirado G, S.; Olvera A, R.

2014-08-01

Zn O films and those superficially modified with chromium were deposited on substrates of soda-lime glass, using the Sol-Gel process and the repeated immersion method. Starting from dehydrated zinc acetate was prepared a solution to 0.6 M to ambient temperature in 2-methoxyethanol and monoethanolamine (Mea) stirring magnetically. The Sol was prepared with an aging to seven days and was used to grow a films group with thickness to eight immersions. These same films were superficially modified with several depositions of a chromium nitrate Sol dissolved in ethanol to low concentration. The Zn O films were structurally characterized by X-ray diffraction, its chemical composition by energy dispersive X-ray spectroscopy and its morphology by scanning electron microscopy and atomic force microscopy, as well as their optical properties by UV-vis. Of the obtained results are proposed possible applications. (author)

Study of silica sol-gel materials for sensor development

Science.gov (United States)

Lei, Qiong

Silica sol-gel is a transparent, highly porous silicon oxide glass made at room temperature by sol-gel process. The name of silica sol-gel comes from the observable physical phase transition from liquid sol to solid gel during its preparation. Silica sol-gel is chemically inert, thermally stable, and photostable, it can be fabricated into different desired shapes during or after gelation, and its porous structure allows encapsulation of guest molecules either before or after gelation while still retaining their functions and sensitivities to surrounding environments. All those distinctive features make silica sol-gel ideal for sensor development. Study of guest-host interactions in silica sol-gel is important for silica-based sensor development, because it helps to tailor local environments inside sol-gel matrix so that higher guest loading, longer shelf-life, higher sensitivity and faster response of silica gel based sensors could be achieved. We focused on pore surface modification of two different types of silica sol-gel by post-grafting method, and construction of stable silica hydrogel-like thin films for sensor development. By monitoring the mobility and photostability of rhodamine 6G (R6G) molecules in silica alcogel thin films through single molecule spectroscopy (SMS), the guest-host interactions altered by post-synthesis grafting were examined. While physical confinement remains the major factor that controls mobility in modified alcogels, both R6G mobility and photostability register discernable changes after surface charges are respectively reversed and neutralized by aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTES) grafting. The change in R6G photostability was found to be more sensitive to surface grafting than that of mobility. In addition, silica film modification by 0.4% APTS is as efficient as that by pure MTES in lowering R6G photostability, which suggests that surface charge reversal is more effective than charge neutralization

Luminescent hybrid porphyrinosilica obtained by sol gel chemistry

Directory of Open Access Journals (Sweden)

Neri Cláudio Roberto

2003-01-01

Full Text Available The sol-gel process is a methodology used to obtain organic-inorganic hybrid solids, which open new possibilities in the field of material science. The sol-gel technique offers a low temperature attractive approach for introducing organic molecules into amorphous materials. In order to introduce tetrakis (2-hydroxy-5-nitrophenylporphyrin covalently bounded to a silicate matrix, the inorganic precursor 3-isocyanatopropyltriethoxysilane was added (molar ratio 2:1 to the porphyrin solution in anhydrous dimethylformamide and triethylamine. The isolated porphyrin and the hybrid porphyrinosilica have excitation maximum centred at 400 nm and 424 nm, respectively and the emission spectra for both materials has bands centred at 650 nm and 713 nm. The formation of hybrid matrix was investigated by FTIR.

Preparation of TiO2 thin films from autoclaved sol containing needle-like anatase crystals

International Nuclear Information System (INIS)

Ge Lei; Xu Mingxia; Fang Haibo; Sun Ming

2006-01-01

A new inorganic sol-gel method was introduced in this paper to prepare TiO 2 thin films. The autoclaved sol with needle-like anatase crystals was synthesized using titanyl sulfate (TiOSO 4 ) and peroxide (H 2 O 2 ) as starting materials. The transparent anatase TiO 2 thin films were prepared on glass slides from the autoclaved sol by sol-gel dip-coating method. A wide range of techniques such as Fourier transform infrared transmission spectra (FT-IR), X-ray diffraction (XRD), thermogravimetry-differential thermal analysis (TG-DTA), scanning electron microscopes, X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible spectrum were applied to characterize the autoclaved sol and TiO 2 thin films. The results indicate that the autoclaved sol is flavescent, semitransparent and stable at room temperature. The anatase crystals of TiO 2 films connect together to form net-like structure after calcined and the films become uniform with increasing heating temperature. The surface of the TiO 2 films contain not only Ti and O elements, but also a small amount of N and Na elements diffused from substrates during heat treatment. The TiO 2 films are transparent and their maximal light transmittances exceed 80% under visible light region

Electric probe diagnostics for measuring SOL parameters, wall and divertor fluxes in KSTAR

Energy Technology Data Exchange (ETDEWEB)

Kim, Heung-Su, E-mail: kimhs@nfri.re.kr [National Fusion Research Institute, Daejeon (Korea, Republic of); Bak, Jun-Gyo [National Fusion Research Institute, Daejeon (Korea, Republic of); Bae, Min-Keun; Chung, Kyu-Sun [Hanyang University, Seoul (Korea, Republic of); Hong, Suk-Ho [National Fusion Research Institute, Daejeon (Korea, Republic of)

2016-11-01

Highlights: • Some components in EPDs were improved to investigate characteristics of the SOL plasmas and to measure wall and divertor fluxes in the KSTAR tokamak plasmas. From the upgrades in the EPDs, the measured error of the elapsed distance for the evaluation of the SOL profiles can be reduced up to 1%. • In the SOL parameter measurement during IWL plasma, the e-folding lengths in the main SOL region lTe and lne were evaluated as 3.5 cm and 2.1 cm, respectively. • From flux measurement at the far SOL during a diverted ELMy H-mode, peaked heat flux toward to outboard wall during ELMs might be less than 1% of the peaked divertor heat flux. • The movement of an OSP during a diverted H-mode can be detected from the divertor probe measurement, and the peaked heat flux near the OSP was estimated as few MW m-2. - Abstract: Some components in electric probe diagnostics (EPDs) are improved in order to investigate characteristics of edge plasmas in the upstream scrape-off-layer (SOL) region and to measure wall and divertor fluxes during L-mode and H-mode plasma discharges in the Korea Superconducting Tokamak Advanced Research (KSTAR). From the upgrades in the EPDs, the measured error of the elapsed distance for the evaluation of the SOL profiles can be reduced up to 1% and the ion saturation current of up to 1.0 A near an outer strike point (OSP) can be measured at the divertor region. In the SOL profile measurements during L-mode and inner wall limited plasma (B{sub T} = 2.0 T, I{sub p} = 0.4 MA), the e-folding lengths in the main SOL region λ{sub Te} and λ{sub ne} are evaluated as 3.5 cm and 2.1 cm, respectively. From particle flux measurement at the far SOL region during a diverted ELMy H-mode discharge (B{sub T} = 1.8 T, I{sub p} = 0.65 MA), peaked heat flux toward to outboard wall during ELM bursts is estimated up to ∼20 k Wm{sup −2}, which may be less than 1% of the peaked divertor heat flux expected for the neutral beam (NB) heating power P{sub NB

78 FR 45268 - Notice of Availability of the San Diego Gas & Electric Ocotillo Sol Solar Project Final...

Science.gov (United States)

2013-07-26

...] Notice of Availability of the San Diego Gas & Electric Ocotillo Sol Solar Project Final Environmental...) Ocotillo Sol Solar Project in Imperial County, California, and by this notice is announcing its... Ocotillo Sol Solar Project Final EIS/Proposed CDCA Plan Amendment have been sent to affected Federal, State...

Effectiveness of silica based sol-gel microencapsulation method for odorants and flavors leading to sustainable environment.

Science.gov (United States)

Ashraf, Muhammad Aqeel; Khan, Aysha Masood; Ahmad, Mushtaq; Sarfraz, Maliha

2015-01-01

Microencapsulation has become a hot topic in chemical research. Technology mainly used for control release and protection purposes. The sol-gel micro encapsulation approach for fragrance and aroma in porous silica-based materials leads to sustainable odorant and flavored materials with novel and unique beneficial properties. Sol-gel encapsulation of silica based micro particles considered economically cheap as capital investment in manufacturing is very low and environmentally friendly. Amorphous sol-gel SiO2 is non-toxic and safe, whereas the sol-gel entrapment of delicate chemicals in its inner pores results in pronounced chemical and physical stabilization of the entrapped active agents, thereby broadening the practical utilization of chemically unstable essential oils (EOs). Reviewing progress in the fabrication of diverse odorant and flavored sol-gels, shows us how different synthetic strategies are appropriate for practical application with important health and environmental benefits.

Fluorescence metrology of silica sol-gels

Indian Academy of Sciences (India)

We have developed a new method for measuring in-situ the growth of the nanometre-size silica particles which lead to the formation of sol-gel glasses. This technique is based on the decay of fluorescence polarisation anisotropy due to Brownian rotation of dye molecules bound to the particles. Results to date give near ...

Morphology and the isoelectric point of nanosized aqueous ceria sols

Energy Technology Data Exchange (ETDEWEB)

Gulicovski, Jelena J. [The Vinča Institute of Nuclear Sciences, University of Belgrade, POB 522, 11001 Belgrade (Serbia); Bračko, Ines [Advanced Materials Department, Jozef Stefan Institute, Ljubljana (Slovenia); Milonjić, Slobodan K., E-mail: smiloni@vinca.rs [The Vinča Institute of Nuclear Sciences, University of Belgrade, POB 522, 11001 Belgrade (Serbia)

2014-12-15

Ceria sols were synthesized by a forced hydrolysis method using cerium sulphate or cerium nitrate as precursors. High-resolution TEM was used to determine the microstructure and particle size of CeO{sub 2}. A polycrystalline structure of ceria sols with crystallite sizes of 4.4 and 8.6 nm was obtained. The particles had a well-defined polyhedral shape. Direct bandgaps for ceria nanoparticles were 2.80 and 3.31 eV, respectively. The isoelectric point, pH{sub iep}, of ceria sols in KNO{sub 3} solutions was investigated. The isoelectric point of ceria was found to be pH{sub iep} = 7.6 ± 0.2. The obtained results indicate that the isoelectric point in the presence of SO{sub 4}{sup 2−} ions shifts to lower pH value. The particle size of ceria increases with pH, reaching the maximum value at pH{sub iep} as the result of agglomeration{sub .} - Highlights: • Ceria sols with cubic phase nanoparticles have been successfully synthesized. • The isoelectric point of ceria oxide in KNO{sub 3} solutions was p{sub Hiep} = 7.6 ± 0.2. • The specific adsorption of SO{sub 4}{sup 2−} ions causes a shift in IEP to lower pH (pH{sub iep} = 6.7). • The correlation between IEP and the maximum diameter of particles was observed.

Synthesis of cadmium tungstate films via sol-gel processing

Energy Technology Data Exchange (ETDEWEB)

Lennstrom, Kirk; Limmer, Steven J.; Cao Guozhong

2003-06-23

Cadmium tungstate is a scintillator material with excellent intrinsic photoluminescent properties. It is highly resistant to gamma radiation, has an almost non-existent afterglow and is highly efficient. Cadmium tungstate is also non-hydroscopic, unlike the more prevalent thallium-doped alkali halide scintillators. In order to create thin films of cadmium tungstate with precise stoichiometric control, a sol-gel processing technique has been applied to produce this material for the first time. In addition to lower processing temperatures, sol-gel-derived cadmium tungstate is cheaper and easier than other technologies, particularly for thin films. Furthermore, it has the potential to produce nanostructured materials with good optical quality. X-Ray diffraction results of sol-gel-derived materials fired at various temperatures imply crystallization of cadmium tungstate without the intermediate formation of either tungsten oxide or cadmium oxide. Scanning electron microscopy analysis shows the formation of nano-sized particles prior to heat treatment, which form meso-sized particles after the heat treatment. Photoluminesce analysis indicates emission of derived films at 480 nm, which agrees with other published data. Finally, the efficiency of derived films was approximately 6%{+-}1.8%.

El "yo" de la detective: Dolores Redondo y Carolina Solé

Directory of Open Access Journals (Sweden)

Melissa M. Culver

2015-10-01

Full Text Available Las últimas narrativas policiacas españolas escritas por mujeres, tales como El guardián invisible (Redondo, 2013 y Ojos de hielo (Solé, 2013, se caracterizan por la fuerte presencia e incluso capital importancia de la subjetividad investigadora en la resolución del crimen. En este artículo se plantea, de un lado, el hecho de que esta subjetividad de la detective se configura a partir de su oposición al carácter cientificista de la realidad actual en la investigación policiaca —basada en el cotejo de muestras de ADN y dominada por la figura de los perfiladores— y se analiza, de otro, esta oposición como radical contradicción que da lugar a una narrativa policiaca “otra” en la que, frente a la tradición del género negro clásico, se privilegia la vida sobre la muerte.

Opportunity's Surroundings on Sol 1798 (Stereo)

Science.gov (United States)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11850 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11850 NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this stereo 180-degree view of the rover's surroundings during the 1,798th Martian day, or sol, of Opportunity's surface mission (Feb. 13, 2009). North is on top. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 111 meters (364 feet) southward on the preceding sol. Tracks from that drive recede northward in this view. For scale, the distance between the parallel wheel tracks is about 1 meter (about 40 inches). The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock. This view is presented as a cylindrical-perspective projection with geometric seam correction.

Opportunity's Surroundings on Sol 1818 (Stereo)

Science.gov (United States)

2009-01-01

[figure removed for brevity, see original site] Left-eye view of a color stereo pair for PIA11846 [figure removed for brevity, see original site] Right-eye view of a color stereo pair for PIA11846 NASA's Mars Exploration Rover Opportunity used its navigation camera to take the images combined into this full-circle view of the rover's surroundings during the 1,818th Martian day, or sol, of Opportunity's surface mission (March 5, 2009). South is at the center; north at both ends. This view combines images from the left-eye and right-eye sides of the navigation camera. It appears three-dimensional when viewed through red-blue glasses with the red lens on the left. The rover had driven 80.3 meters (263 feet) southward earlier on that sol. Tracks from the drive recede northward in this view. The terrain in this portion of Mars' Meridiani Planum region includes dark-toned sand ripples and lighter-toned bedrock. This view is presented as a cylindrical-perspective projection with geometric seam correction.

Impediment to Spirit Drive on Sol 1806

Science.gov (United States)

2009-01-01

The hazard avoidance camera on the front of NASA's Mars Exploration Rover Spirit took this image after a drive by Spirit on the 1,806th Martian day, or sol, (January 31, 2009) of Spirit's mission on the surface of Mars. The wheel at the bottom right of the image is Spirit's right-front wheel. Because that wheel no longer turns, Spirit drives backwards dragging that wheel. The drive on Sol 1806 covered about 30 centimeters (1 foot). The rover team had planned a longer drive, but Spirit stopped short, apparently from the right front wheel encountering the partially buried rock visible next to that wheel. The hazard avoidance cameras on the front and back of the rover provide wide-angle views. The hill on the horizon in the right half of this image is Husband Hill. Spirit reached the summit of Husband Hill in 2005.

Phoenix Robotic Arm's Workspace After 90 Sols

Science.gov (United States)

2008-01-01

During the first 90 Martian days, or sols, after its May 25, 2008, landing on an arctic plain of Mars, NASA's Phoenix Mars Lander dug several trenches in the workspace reachable with the lander's robotic arm. The lander's Surface Stereo Imager camera recorded this view of the workspace on Sol 90, early afternoon local Mars time (overnight Aug. 25 to Aug. 26, 2008). The shadow of the the camera itself, atop its mast, is just left of the center of the image and roughly a third of a meter (one foot) wide. The workspace is on the north side of the lander. The trench just to the right of center is called 'Neverland.' The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

Effect of concentrations of plasticizers on the sol-gel properties developed from alkoxides precursors

Directory of Open Access Journals (Sweden)

Sandra Raquel Kunst

Full Text Available Abstract Coatings developed through sol-gel method is presented as an interesting replacement to chromium coating. Sol-gel method present advantages as high purity and excellent distribution of the components. The objective of this work is to synthesize and characterize a film obtained by sol-gel route. The film was prepared with 3-(trimethoxysilylpropyl methacrylate (TMSPMA, tetraethoxysilane (TEOS and cerium nitrate, using water and ethanol as solvents. Polyethyleneglycol (PEG plasticizer was added at four different concentrations. The sol was characterized by techniques of viscosity, thermogravimetric analysis (TGA, X-ray diffraction (XRD nuclear magnetic resonance spectroscopy (NMR and Fourier transform infrared spectroscopy (FT-IR. The results showed that tetrafunctional alkoxides condensation was retarded by the plasticizer, forming a compact film. The film with 20 g.L-1 of PEG showed the best electrochemical behavior.

Effect of asymmetric plasma potential in the SOL on the particle radial transport and heat flux broadening

International Nuclear Information System (INIS)

Hara, Junichiro; Uesugi, Yoshihiko; Miura, Yukitoshi; Kawashima, Hisato.

1997-01-01

The effective divertor heat-load relaxation using ExB induced convective cells in the SOL is studied. The ExB convective cells in the SOL are generated by the toroidally asymmetric divertor biasing, which can control the local plasma potential in the SOL. The preliminary experiment has been done in the JFT-2M tokamak with poloidal divertor. The helical SOL current flows along the magnetic field between the locally biased inboard plate and grounded outer plates, thereby modifying plasma potential in the vicinity of the local divertor current flow. The generation of the poloidal electric field reaching up to 1.5kV/m locally in the SOL and the modification of the heat flux profile on the divertor plate is observed. (author)

Study on preparation of orange-emitting phosphor Y3Mg2AlSi2O12: Ce3+ for wLED

Directory of Open Access Journals (Sweden)

Yan Shirun

2017-12-01

Full Text Available Ce3+-doped garnet-structured orange-emitting phosphor Y3Mg2AlSi2O12:Ce3+ was prepared by sol-gel combustion using urea as a fuel.Effects of the reduction temperature,Ce3+ doping concentration on the structure,morphology,and photoluminescence property of the as-prepared phosphor were investigated by X-ray diffraction(XRD,scaning electron microscope(SEM,photoluminescence spectroscopy and UV-Vis reflection spectroscopy.The crystallinities,morphologies,and photoluminescence properties of the phosphors prepared by sol-gel combustion and solid-state reaction were compared.The reasons causing different performance of the phosphors were discussed.

Sol-gel process for the manufacture of high power switches

Science.gov (United States)

Landingham, Richard L.; Satcher, Jr, Joe; Reibold, Robert

2016-09-27

According to one embodiment, a photoconductive semiconductor switch includes a structure of nanopowder of a high band gap material, where the nanopowder is optically transparent, and where the nanopowder has a physical characteristic of formation from a sol-gel process. According to another embodiment, a method includes mixing a sol-gel precursor compound, a hydroxy benzene and an aldehyde in a solvent thereby creating a mixture, causing the mixture to gel thereby forming a wet gel, drying the wet gel to form a nanopowder, and applying a thermal treatment to form a SiC nanopowder.

rhEGF-containing thermosensitive and mucoadhesive polymeric sol-gel for endoscopic treatment of gastric ulcer and bleeding.

Science.gov (United States)

Maeng, Jin Hee; So, Jung Won; Kim, Jungju; Kim, In Ae; Jung, Ji Hoon; Min, Kyunghyun; Lee, Don Haeng; Yang, Su-Geun

2014-03-01

Gastrointestinal endoscopy is a standard diagnostic tool for gastrointestinal ulcers and cancer. In this study, we have developed recombinant human epidermal growth factor-containing ulcer-coating polymeric sol-gel for endoscopic application. Chitosan and pluronic F127 were employed for their thermoresponsive and bioadhesive properties. At temperatures below 21, polymeric sol-gel remains liquid during endoscopic application and transforms to gel at body temperature after application on ulcers. In an in vitro cellular wounding assay, recombinant human epidermal growth factor sol-gel significantly enhanced the cell migration and decreased the wounding area (68%) compared to nontreated, recombinant human epidermal growth factor solution, and sol-gel without recombinant human epidermal growth factor (42, 49, and 32 % decreased at day 1). The in vivo ulcer-healing study was performed in an acetic acid-induced gastric ulcer rat model and proved that our recombinant human epidermal growth factor endoscopic sol-gel facilitated the ulcer-healing process more efficiently than the other treatments. Ulcer sizes in the recombinant human epidermal growth factor sol-gel group were decreased 2.9- and 2.1-fold compared with those in the nontreated group on days 1 and 3 after ulceration, respectively. The mucosal thickness in the recombinant human epidermal growth factor sol-gel group was significantly increased compared to that in the nontreated group (3.2- and 6.9-fold on days 1 and 3 after ulceration, respectively). In a gastric retention study, recombinant human epidermal growth factor sol-gel stayed on the gastric mucosa more than 2 h after application. The present study suggests that recombinant human epidermal growth factor sol-gel is a prospective candidate for treating gastric ulcers via endoscopic application.

Fast and efficient proteolysis by reusable pepsin-encapsulated magnetic sol-gel material for mass spectrometry-based proteomics applications.

Science.gov (United States)

Kayili, H Mehmet; Salih, Bekir

2016-08-01

Hydrophobic silicon-based material having magnetic properties was fairly synthesized by a classical sol-gel approach. Pepsin enzyme was encapsulated in the sol-gel material and the enzyme activity was evaluated in consequence of the digestion of some common proteins such as α- and β-casein, cytochrome c, myoglobin, and bovine serum albumin (BSA) both in a single protein batch and in the protein mixture. The optimum digestion time of the studied proteins using pepsin-encapsulated magnetic sol-gel material was found to be 20min. To produce the magnetic sol-gel material for convenient and easy proteomics applications, Fe3O4 was doped inside sol-gel material during the gelation step. It was observed that the activity of encapsulated pepsin was not affected by the amount of Fe3O4. Poly(ethylene glycol) was also inserted in sol-gel bulk to obtain suitable roughness and increase the hydrophilicity of the material surface to let protein molecules reach to the sol-gel material easily. The digestion of the protein mixture and non-fat bovine milk was performed with the pepsin-encapsulated magnetic sol-gel material and the digested solutions were analyzed using SDS-PAGE, MALDI-TOF-MS and LC-MS/MS for the protein identification. Reusability of the pepsin-encapsulated sol-gel material was examined and it was determined that they could be used at least 20 times. Finally, IgG digestions with a fast incubation time period were carried out using pepsin-encapsulated sol-gel material for generation of (Fab)2 product to evaluate the kinetic performance of the material. Copyright © 2016 Elsevier B.V. All rights reserved.

Dip coating of sol-gels

Science.gov (United States)

Schunk, P. R.; Hurd, A. J.; Brinker, C. J.

Dip coating is the primary means of depositing sol-gel films for precision optical coatings. Sols are typically multicomponent systems consisting of an inorganic phase dispersed in a solvent mixture, with each component differing in volatility and surface tension. This, together with slow coating speeds (less than 1cm/s), makes analysis of the coating process complicated; unlike most high-speed coating methods, solvent evaporation, evolving rheology, and surface tension gradients alter significantly the fluid mechanics of the deposition stage. These phenomena were studied with computer-aided predictions of the flow and species transport fields. The underlying theory involves mass, momentum, and species transport on a domain of unknown shape, with models and constitutive equations for vapor-liquid equilibria and surface tension. Due accounting is made for the unknown position of the free surface, which locates according to the capillary hydrodynamic forces and solvent loss by evaporation. Predictions of the effects of mass transfer, hydrodynamics, and surface tension gradients on final film thickness are compared with ellipsometry measurements of film thickness on a laboratory pilot coater. Although quantitative agreement is still lacking, both experiment and theory reveal that the film profile near the drying line takes on a parabolic shape.

Bright Soil Churned by Spirit's Sol 1861 Drive

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit drove 22.7 meters (74 feet) toward the southwest on the 1,861st Martian day, or sol, of Spirit's mission on Mars (March 28, 2009). After the drive, the rover took this image with its front hazard-avoidance camera, looking back at the tracks from the drive. As usual since losing the use of its right-front wheel in 2006, Spirit drove backwards. The immobile right-front wheel churned up a long stripe of bright soil during this drive. Where Spirit has found such bright soil in the past, subsequent analysis of the composition found concentrations of sulfur or silica that testified to past action of water at the site. When members of the rover team saw the large quantity of bright soil exposed by the Sol 1861 drive, they quickly laid plans to investigate the composition with Spirit's alpha particle X-ray spectrometer. The Sol 1861 drive took the rover past the northwest corner of the low plateau called 'Home Plate,' making progress on a route around the western side of Home Plate. The edge of Home Plate forms the horizon on the right side of this image. Husband Hill is on the horizon on the left side. For scale, the parallel rover wheel tracks are about 1 meter (40 inches) apart. The rover's hazard-avoidance cameras take 'fisheye' wide-angle images.

77 FR 28618 - Notice of Availability of the San Diego Gas & Electric Ocotillo Sol Solar Project Draft...

Science.gov (United States)

2012-05-15

...] Notice of Availability of the San Diego Gas & Electric Ocotillo Sol Solar Project Draft Environmental... & Electric (SDG&E) Ocotillo Sol Solar Project in Imperial County, California, and by this notice is... comments related to the SDG&E Ocotillo Sol Solar Project by any of the following methods: Web site: http...

Gelatin Template Synthesis of Aluminum Oxide and/or Silicon Oxide Containing Micro/Mesopores Using the Proteic Sol-Gel Method

Directory of Open Access Journals (Sweden)

Amanda Sayure Kasuya de Oliveira

2017-01-01

Full Text Available Aluminum oxide and/or silicon oxide-based supports were synthesized by proteic sol-gel method. The characterization was performed through the analysis of TG, XRD, FTIR, SEM, and N2 physisorption. The XRD diffractograms showed an amorphous material profile. TG results indicate the total liberation of the organic and inorganic material in the calcination temperature used, occurring in different mass loss range. This piece of information was reaffirmed by the FTIR spectra, which presented characteristic bands of gelatin structure before calcinations which disappear in the spectrum of the solid after calcinations, indicating the loss of organic matter from gelatin after heat treatment. The spectra exhibited M-O stretching vibration at low wavenumbers after calcinations related to metal oxides. The acquired images by SEM suggest the obtaining of a highly porous material with very different characteristics depending on the composition of the support. The N2 isotherms indicate the presence of a micro/mesoporous oxide with interesting textural properties, particularly for the supports containing aluminum and silicon oxide. The ethanol dehydration results showed greater selectivity to diethyl ether compared to ethylene. From the reaction data, the following order of acid strength was obtained: 2Si-Al > Si-2Al > Si-Al > Al, which is related to the Si-Al ratio.

Driving mechanism of SOL plasma flow and effects on the divertor performance in JT-60U

International Nuclear Information System (INIS)

Asakura, N.

2002-01-01

SOL plasma flow plays an important role in the plasma transport along the field lines, and influences control of the divertor plasma and impurity ions. Recently, mechanisms producing the SOL flow such as drifts produced by electric field and pressure gradient are pointed out. In JT-60U, three reciprocating Mach probes were installed at the high-field-side (HFS) baffle, low-field-side (LFS) midplane and just below the X-point. The measurements of the SOL flow and plasma profiles both at the HFS and LFS, for the first time, found out the SOL flow pattern and its driving mechanism. 'Flow reversal' was found near the separatrix of the HFS and LFS. Radial profiles of the SOL flow were similar to those calculated numerically using the UEDGE code with the plasma drifts included. SOL particle fluxes towards the HFS and LFS divertors were, for the first time, evaluated. Important physics issues for the divertor design and operation, such as in-out asymmetries of the heat and particle fluxes, and control of impurity ions with intense gas puff and divertor pump (puff and pump), were investigated. (author)

Studies on silica sol-clay particle interactions by small-angle neutron scattering

International Nuclear Information System (INIS)

Moini, A.; Pinnavaia, T.J.; Michigan State Univ., East Lansing; Thiyagarajan, P.; White, J.W.

1988-01-01

SANS data were collected on a series of hydrolyzed silica and silica-clay complexes prepared from a 40 A silica sol and aqueous suspensions of Na + montmorillonite. The hydrolyzed silica product showed a peak centered at Q=0.0856 A -1 corresponding to a distance of 73 A between the sol particles. For such an evaporated gel in which the particles are in close contact, this distance is expected to be very close to the particle diameter indicating partial aggregation of the original spheres. A similar feature was observed in the SANS data for silica-clay products indicating the presence of some unintercalated silica. The intensity of this scattering was found to be dependent on the silica:clay ratio and the reaction time. The SANS data in the region from Q=0.006 to 0.025 A -1 were characteristic of clay scattering and exhibited a power-law behavior. The change in the slope of this curve upon reaction of the clay with the silica sol was interpreted in terms of a separation of clay platelets caused by a binding interaction with the sol particles. (orig.)

Effect of heating scheme on SOL width in DIII-D and EAST

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L. Wang

2017-08-01

Full Text Available Joint DIII-D/EAST experiments in the radio-frequency (RF heated H-mode scheme with comparison to that of neutral beam (NB heated H-mode scheme were carried out on DIII-D and EAST under similar conditions to examine the effect of heating scheme on scrape-off layer (SOL width in H-mode plasmas for application to ITER. A dimensionally similar plasma equilibrium was used to match the EAST shape parameters. The divertor heat flux and SOL widths were measured with infra-red camera in DIII-D, while with divertor Langmuir probe array in EAST. It has been demonstrated on both DIII-D and EAST that RF-heated plasma has a broader SOL than NB-heated plasma when the edge electrons are effectively heated in low plasma current and low density regime with low edge collisionality. Detailed edge and pedestal profile analysis on DIII-D suggests that the low edge collisionality and ion orbit loss effect may account for the observed broadening. The joint experiment in DIII-D has also demonstrated the strong inverse dependence of SOL width on the plasma current in electron cyclotron heated (ECH H-mode plasmas.

Effectiveness of silica based sol-gel microencapsulation method for odorants and flavors leading to sustainable environment

Science.gov (United States)

Ashraf, Muhammad Aqeel; Khan, Aysha Masood; Ahmad, Mushtaq; Sarfraz, Maliha

2015-01-01

Microencapsulation has become a hot topic in chemical research. Technology mainly used for control release and protection purposes. The sol-gel micro encapsulation approach for fragrance and aroma in porous silica-based materials leads to sustainable odorant and flavored materials with novel and unique beneficial properties. Sol-gel encapsulation of silica based micro particles considered economically cheap as capital investment in manufacturing is very low and environmentally friendly. Amorphous sol-gel SiO2 is non-toxic and safe, whereas the sol-gel entrapment of delicate chemicals in its inner pores results in pronounced chemical and physical stabilization of the entrapped active agents, thereby broadening the practical utilization of chemically unstable essential oils (EOs). Reviewing progress in the fabrication of diverse odorant and flavored sol-gels, shows us how different synthetic strategies are appropriate for practical application with important health and environmental benefits. PMID:26322304

Study of the Effect of Sol pH and Nanoclay Incorporation on the Corrosion Protection Performance of a Silane Sol-Gel Coating

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Najmeh Asadi

2014-06-01

Full Text Available This work is aimed to evaluate the role of nanoclay in the protective performance of an eco-friendly silane sol-gel layer applied on mild steel substrate in 0.1M sodium chloride solution. At the first step, the effect of pH of the silane solution, consisting of a mixture of γ-glycidoxypropiltrimethoxysilane and methyltriethoxysilane and tetraethoxysilane, on the coating performance was evaluated through electrochemical noise measurements. The values of characteristic charge as a parameter extracted from shot noise theory revealed that the sol pH determining the rate of hydrolysis can play an important role in the corrosion protection behavior of silane coatings. Then, the influence of clay nanoparticles on the corrosion protective performance of the hybrid silane film was studied through taking advantage of electrochemical techniques, including electrochemical impedance spectroscopy and polarization curves, as well as surface analysis methods. The obtained electrochemical data including the values of charge transfer resistance, coating resistance, low frequency impedance and corrosion current density showed that the silane sol gel film in the presence of clay nanoparticles can present an improved corrosion protection. The behavior was connected to an enhancement in the coating barrier properties. Moreover, FESEM and water contact angle confirmed the higher reticulation in case of the coating incorporating nanoclay.

Morphology, structure and optical properties of sol-gel ITO thin films

Energy Technology Data Exchange (ETDEWEB)

Stoica, T.F.; Teodorescu, V.S.; Blanchin, M.G.; Stoica, T.A.; Gartner, M.; Losurdo, M.; Zaharescu, M

2003-08-15

The alkoxidic route and the spinning deposition were used to prepare monolayer sol-gel indium tin oxide (ITO) films. The morphology and crystalline structure were investigated by cross-section transmission electron microscopy (XTEM) and atomic force microscopy (AFM). The ITO sol-gel mono-layer contains three regions of different porosities. The basic crystalline structure is that of the In{sub 2}O{sub 3} lattice. The optical properties have been studied by optical transmission and spectroscopic ellipsometry.

Fabrication and study of sol-gel ZnO films for use in Si-based heterojunction photovoltaic devices

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Daniya Mukhamedshina

2017-12-01

Full Text Available This paper considers the use of zinc oxide thin films prepared via the sol-gel route as an n-type layer in heterojunction ZnO/Si solar cells. The ZnO films were prepared via a simple spin-coating technique using zinc acetate dihydrate as a zinc precursor, isopropanol as a solvent and monoethanolamine as a stabilizing agent. Optical, structural and morphological properties of ZnO were investigated for thin films grown from sol-gel solutions with different concentrations both on glass and silicon substrates. As such, a distribution of crystallite sizes and surface topology parameters corresponding to various zinc acetate dihydrate concentrations were obtained to elucidate optimal film deposition conditions. Correlation between thin film morphology and structural characteristics of ZnO thin films was made based on atomic-force microscopy studies. Finally, our results on fabrication, characterization and simulation of ZnO/Si heterojunctions for use as photovoltaic devices are presented. Although noticeable rectifying and photovoltaic properties were observed for Al/Si/ZnO/Ti/Au devices, there appears to exist a considerable room for device improvement with simulation studies suggesting that efficiencies of the order of 24% may be obtained for devices with optimal silicon wafer passivation, i.e. with lifetimes of the order of 1000 μs.

Stability of zirconia sol in the presence of various inorganic electrolytes

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Marković Jelena P.

2013-01-01

Full Text Available Zirconia sol was prepared from zirconium oxychloride solutions by forced hydrolysis at 102ºC. The prepared sol consisted of almost spherical, monoclinic, hydrated zirconia particles 61 nm in diameter. The stability of zirconia sol in the presence of various inorganic electrolytes (LiCl, NaCl, KCl, CsCl, KBr, KI, KNO3, and K2SO4 was studied by potentiometric titration method. Dependence of the critical concentration of coagulation (CCC on the dispersion pH was determined for all studied electrolytes. The critical coagulation concentration values, for all investigated electrolytes, are lower at higher pH. These values for all 1:1 electrolytes are equal in the range of experimental error. For a given pH value, CCCs of K2SO4 are 3-4 orders of magnitude lower than the corresponding values for 1:1 electrolytes. [Projekat Ministarstva nauke republike Srbije, br. III 45012

Persistent superhydrophilicity of sol-gel derived nanoporous silica thin films

International Nuclear Information System (INIS)

Ganjoo, S; Azimirad, R; Akhavan, O; Moshfegh, A Z

2009-01-01

In this investigation, sol-gel synthesized nanoporous silica thin films, annealed at different temperatures, with long time superhydrophilic property have been studied. Two kinds of sol-gel silica thin films were fabricated by dip-coating of glass substrates in two different solutions; with low and high water. The transparent coated films were dried at 100 deg. C and then annealed in a temperature range of 200-500 deg. C. The average water contact angle of the silica films prepared with low water content and annealed at 300 deg. C measured about 5 deg. for a long time (6 months) without any UV irradiation. Instead, adding water into the sol resulted in silica films with an average water contact angle greater than 60 deg. Atomic force microscopic analysis revealed that the silica films prepared with low water had a rough surface (∼30 nm), while the films prepared with high water had a smoother surface (∼2 nm). Using x-ray photoelectron spectroscopy, we have shown that with a decrease in the surface water on the film, its hydrophilicity increases logarithmically.

Fabrication of Meso-Porous Gamma-Alumina Films by Sol-Gel and Gel Casting Processes for Making Moisture Sensors

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Kalyan Kumar Mistry

2007-04-01

Full Text Available Meso-porous g-Al2O3 film may be used as a highly sensitive trace moisture sensor. The crack-free alumina film was developed using a combination of sol-gel and tape casting processes, which produce high porosity, high surface area and small pore dimensions in the range of few nano-meter at uniform distribution. Sol-gel processes are well known in nano-technology and nano-material preparation, but it is difficult to make crack-free thick or thin films using this method. Tape cast methods are used for the fabrication of flexible crack-free thick ceramic sheets. Our objective was to develop nano-structured, crack-free, transparent Al2O3 film a few microns thick, has a highly porous and stable crystallographic nature. A metallic paste was printed by screen printing on both side of the film surface for electrodes to form a sensitive element. A silver wire (dia j=0.1mm lead was connected to a grid structure electrode using a silver paste spot for fine joining. Alumina is absorbs moisture molecules into its meso-porous layer and changes its electrical characteristics according to the moisture content, its dielectric constant increase as moisture increase. Moisture molecules can be conceived of as dipoles in random state before the application of an electric field. When the dipole orientation was changed from random to an equilibrium state under the application of external field, a large change in dielectric constant was observed. The number of water molecules absorbed determines the electrical impedance of the capacitor, which in turn is proportional to water vapor pressure.

Silica-sol-based spin-coating barrier layer against phosphorous diffusion for crystalline silicon solar cells.

Science.gov (United States)

Uzum, Abdullah; Fukatsu, Ken; Kanda, Hiroyuki; Kimura, Yutaka; Tanimoto, Kenji; Yoshinaga, Seiya; Jiang, Yunjian; Ishikawa, Yasuaki; Uraoka, Yukiharu; Ito, Seigo

2014-01-01

The phosphorus barrier layers at the doping procedure of silicon wafers were fabricated using a spin-coating method with a mixture of silica-sol and tetramethylammonium hydroxide, which can be formed at the rear surface prior to the front phosphorus spin-on-demand (SOD) diffusion and directly annealed simultaneously with the front phosphorus layer. The optimization of coating thickness was obtained by changing the applied spin-coating speed; from 2,000 to 8,000 rpm. The CZ-Si p-type silicon solar cells were fabricated with/without using the rear silica-sol layer after taking the sheet resistance measurements, SIMS analysis, and SEM measurements of the silica-sol material evaluations into consideration. For the fabrication of solar cells, a spin-coating phosphorus source was used to form the n(+) emitter and was then diffused at 930°C for 35 min. The out-gas diffusion of phosphorus could be completely prevented by spin-coated silica-sol film placed on the rear side of the wafers coated prior to the diffusion process. A roughly 2% improvement in the conversion efficiency was observed when silica-sol was utilized during the phosphorus diffusion step. These results can suggest that the silica-sol material can be an attractive candidate for low-cost and easily applicable spin-coating barrier for any masking purpose involving phosphorus diffusion.

The role of drifts in the plasma transport at the tokamak core–SOL interface

Energy Technology Data Exchange (ETDEWEB)

Chankin, A.V., E-mail: Alex.Chankin@ipp.mpg.de [Max-Planck-Institut für Pasmaphysik, EURATOM Association, 85748 Garching (Germany); Coster, D.P. [Max-Planck-Institut für Pasmaphysik, EURATOM Association, 85748 Garching (Germany)

2013-07-15

The interface between the core (inside the magnetic separatrix in X-point configurations) and the scrape-off layer (SOL) of tokamaks is a delicate region of the magnetic topology transition from closed to open field lines where neither the standard neoclassical theory nor the SOL physics fully apply. Sharp gradients of plasma parameters in the outer core, caused by the proximity of divertor sinks in the near SOL, invalidate some ordering assumptions of the neoclassical theory. At the same time, the existence of closed flux surfaces in the core enforces ambipolarity of radial plasma flows, in difference to the situation in the SOL where the current loop may close through the divertor. Detailed analysis of the plasma transport and flows with the emphasis on the outer core region, just inside the separatrix, is carried out in the paper, based on EDGE2D modelling and analytical formulas.

The role of crosslinkers in epoxy-amine crosslinked silicon sol-gel barrier protection coatings

International Nuclear Information System (INIS)

Vreugdenhil, A.J.; Gelling, V.J.; Woods, M.E.; Schmelz, J.R.; Enderson, B.P.