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Sample records for carbones activados obtenidos

  1. INFLUENCIA DE LA QUÍMICA SUPERFICIAL EN LA ENTALPÍA DE INMERSIÓN DE CARBONES ACTIVADOS EN SOLUCIONES ACUOSAS DE FENOL Y 4-NITRO FENOL

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    Luisa Fernanda Navarrete; Liliana Giraldo; Juan Carlos Moreno

    2008-01-01

    Se estudian las interacciones de cinco muestras de carbón activado obtenidas a partir de diferentes materiales lignocelulósicos, con diferente grado de activación alrededor de 20%, con soluciones acuosas de fenol y 4-nitro fenol mediante la determinación de las entalpías de inmersión. Se establece que los carbones activados obtenidos son de carácter básico y presentan valores para el punto de carga cero (PZC), que varían entre 7,4...

  2. Relación entre el efecto hidrofóbico superficial de carbones activados y la entalpía de inmersión en soluciones acuosas de fenol, 4-nitro fenol y 3-cloro fenol

    OpenAIRE

    Liliana Giraldo; Juan Carlos Moreno

    2009-01-01

    Para cinco carbones activados, obtenidos de materiales lignocelulósicos, se determinan las entalpías de inmersión en soluciones fenólicas. Los carbones activados son de carácter básico con valores del pH en el punto de carga cero, pHPZC, entre 7.4 y 9.7. Se determina la entalpía de inmersión de los carbones activados en CCl4 y agua; a partir de estos resultados, se calcula el factor hidrofóbico, fh, que varía entre 2.98 y 6.75. Las entalpías de inmersión de los carbones activados en solucio...

  3. OBTENCIÓN Y CARACTERIZACIÓN DE CARBONES ACTIVADOS A PARTIR DE SEMILLAS DE MUCUNA SP

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    Juan Moreno

    2009-04-01

    Full Text Available Se obtiene una serie de carbones activados a partir de un material lignocelulósico por activación física con vapor de agua; mucuna Sp es el nombre científico de las semillas utilizadas como precursor lignocelulósico en este trabajo las cuales se trituran y se tamizan para posterior carbonizado, con el objetivo de obtener carbón granular. Se estudia el efecto de la variación de la temperatura (600-900° C y el tiempo (1-10 h de activación, y su relación con las propiedades texturales del carbón. Los carbones activados obtenidos con diferentes porcentajes de quemado (Burn-off se caracterizaron por adsorción física de N2 a 77K. Se evaluó la capacidad de adsorción en solución de los carbones activados por medio del índice de yodo y el índice de azul de metileno. Se encontró una correlación entre los burn-off y las áreas superficiales aparentes calculadas por el método BET con valores cercanos a los 1000 m2g-1, así como con los volúmenes de microporo comprendidos entre 0,060 y 0,400 cm3g-1 , calculados por el método DR y método alfa. La capacidad de adsorción en solución arroja resultados satisfactorios debido a que presenta una buena correlación con los datos de porosidad, factor importante este último a la hora de determinar la posible aplicación del carbón activado.

  4. Caracterización superficial en fase gas y líquida de carbones activados

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    Liliana Giraldo Gutierréz

    2008-05-01

    Full Text Available Se determinó el área superficial de carbones activados obtenidos a partir de cascarilla de café y cáscara de coco, mediante isotermas de adsorción de N2 a 77K. Se compararon los resultados con aquellos obtenidos con un método comúnmente utilizado, el índice de azul de metileno, y se encontró una buena correlación entre las dos áreas determinadas por éste método. Se muestra que los dos métodos permiten realizar un análisis complementario de una superficie porosa./ The superficial area of an activated carbon obtained from coffee husk and coconut shell was determined, by means of isotherms of adsorption of N2 to 77K and the results they area compared with the method of index blue of methylene, finding an good correlation between the two areas determined by this method. This research shows that both methods allow making a complementary analysis of a porous surface.

  5. INFLUENCIA DE LA QUÍMICA SUPERFICIAL EN LA ENTALPÍA DE INMERSIÓN DE CARBONES ACTIVADOS EN SOLUCIONES ACUOSAS DE FENOL Y 4-NITRO FENOL

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    Luisa Fernanda Navarrete

    2008-04-01

    Full Text Available Se estudian las interacciones de cinco muestras de carbón activado obtenidas a partir de diferentes materiales lignocelulósicos, con diferente grado de activación alrededor de 20%, con soluciones acuosas de fenol y 4-nitro fenol mediante la determinación de las entalpías de inmersión. Se establece que los carbones activados obtenidos son de carácter básico y presentan valores para el punto de carga cero (PZC, que varían entre 7,4 y 9,7, y contenidos de basicidad total mayores en todos los casos que los valores obtenidos para la acidez total. Se determina la entalpía de inmersión de los carbones activados en soluciones de NaOH y HCl con valores mayores para la entalpía de inmersión en HCl que se encuentran entre 32,6 y 68,3 Jg-1. Las entalpías de inmersión en solución de fenol se hallan entre 7,6 y 13,9 Jg-1, y para el caso del 4-nitro fenol se encuentran entre 12,7 y 20,5 Jg-1; con valores mayores para todas las muestras para la inmersión en el segundo compuesto.

  6. Relación entre el efecto hidrofóbico superficial de carbones activados y la entalpía de inmersión en soluciones acuosas de fenol, 4-nitro fenol y 3-cloro fenol

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    Liliana Giraldo

    2009-11-01

    Full Text Available Para cinco carbones activados, obtenidos de materiales lignocelulósicos, se determinan las entalpías de inmersión en soluciones fenólicas. Los carbones activados son de carácter básico con valores del pH en el punto de carga cero, pHPZC, entre 7.4 y 9.7. Se determina la entalpía de inmersión de los carbones activados en CCl4 y agua; a partir de estos resultados, se calcula el factor hidrofóbico, fh, que varía entre 2.98 y 6.75. Las entalpías de inmersión de los carbones activados en soluciones de fenol, 4-nitro fenol y 3-cloro fenol están entre 7.6 y 13.9; 12.7 y 20.5; 6.8 y 11.4 Jg-1 respectivamente./For five activated carbons, obtained from lignocellulosic materials the, immersion enthalpies in phenolic solutions are determined. The activated carbons have basic character with values of pH in the point of zero charge, pHPZC, between 7.4 and 9.7. The immersion enthalpies of activated carbons in CCl4 and water are determined, from these results the hydrophobic factor, hf, are calculated, that change between 2.98 and 6.75. The immersion enthalpies of the activated carbons in phenol, 4-nitro phenol and 3-chloro phenol solutions are between 7.6 y 13.9; 12.7 y 20.5; 6.8 y 11.4 Jg-1 respectively

  7. Impacto del tratamiento con ozono sobre las propiedades superficiales del carbón activado Impact of ozone treatment on activated carbon surface properties

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    Héctor Valdés

    2011-08-01

    Full Text Available El uso conjunto de ozono y carbón activado para tratar efluentes tóxicos ha sido demostrado recientemente. Sin embargo, existen dudas acerca del efecto del ozono sobre las propiedades del carbón activado. En este artículo se presentan resultados sobre la modificación de las propiedades superficiales de un carbón activado comercial por la acción del ozono durante diferentes tiempos de exposición. Las propiedades químicas superficiales del carbón activado fueron evaluadas utilizando las técnicas de neutralización selectiva, desorción térmica programada (DTP y el pH del punto de carga cero. Las características texturales fueron evaluadas mediante microscopía electrónica de barrido. El área superficial aparente, el volumen de microporos y mesoporos fueron obtenidos a partir de las isotermas de adsorción de nitrógeno a 77 K. Las propiedades adsortivas fueron caracterizadas por el índice de adsorción de azul de metileno. Los resultados demuestran que los grupos superficiales oxigenados presentes en el carbón activado se modifican producto del tratamiento con el ozono. A mayores dosis de ozono, el carbón sufre mayor oxidación y se incrementan los grupos ácidos en especial los grupos carboxílicos, mientras que el pH de punto de carga cero disminuye. El área BET, así como el volumen de microporos disminuyen al igual que el poder de adsorción de azul de metileno.The combined use of ozone and activated carbon has recently started to be developed for the treatment of toxic effluents. However, the effect of ozone on the properties of activated carbon is not fully elucidated. A study was undertaken of modifications of the surface properties of a commercial activated carbon produced by its ozonation during different time periods. Surface chemistry of the activated carbon samples was characterized by of selective neutralization, temperature-programmed desorption, and pH of the point of zero charge. Surface area and volume of

  8. Efecto de la heterogeneidad sobre las isotermas de adsorción de carbones activados

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    Karim Sapag

    2010-06-01

    Full Text Available Los carbones activados (CA son materiales microporosos que poseen gran capacidad de adsorción. La heterogeneidad de cualquier adsorbente, en particular la de los CA, puede ser separada en dos grandes familias: energética (o superficial y estructural. La heterogeneidad estructural es causada por la presencia de poros de diferentes tamaños y formas, y por su posible interconexión; mientras que la heterogeneidad energética se origina por las irregularidades superficiales, así como por la presencia de grupos funcionales y/o impurezas. En este trabajo se discutirán diferentes modelos de heterogeneidad superficial en materiales con poros de geometría, tipo placas paralelas, y su efecto sobre las isotermas de adsorción y en las distribuciones de tamaño de poros. Activated carbons (AC are microporous materials that have high adsorptive capacity. The heterogeneity of any adsorbent, in particular of the AC, can be separated into two large families: energetic and structural. Structural heterogeneity is caused by the presence of pores of different sizes, shapes and how they are interconnected, while the energy heterogeneity is caused by surface irregularities, as well as by the presence of functional groups and / or impurities. In this paper we discuss different models of surface heterogeneity in materials with slit pores and its effect on adsorption isotherms and the pore size distributions (PSD.

  9. REMOCIÓN DE CROMO VI DE SOLUCIONES ACUOSAS POR ADSORCIÓN SOBRE CARBONES ACTIVADOS MODIFICADOS

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    Nubia Céspedes

    2009-05-01

    Full Text Available En este trabajo se determina la adsorción de Cr6+ de disoluciones acuosas en dos carbones activados comerciales en función del grado de modificación (reducción, oxidación de la superficie de los adsorbentes con tratamientos térmicos en presencia de hidrógeno, oxígeno y ácido nítrico. La química superficial de los carbones activados originales y modificados se examina por los métodos de titulaciones de Böehm y descomposición con temperatura programada (DTP. Los ensayos de evaluación de la capacidad de adsorción se realizan con soluciones modelo de ión cromato y bajo distintas condiciones de concentración inicial, tiempo de contacto, pH del medio, temperatura y masa de adsorbente. Se comprueba que la modificación de la superficie de los adsorbentes afecta el grado de adsorción del ión cromato en la medida en que los sólidos tratados con H2 muestran la mayor  capacidad de remoción. Las variables que afectan favorablemente la extensión de la remoción de cromo son: concentración inicial de 100 ppm,  pH  inicial de  2,0, temperatura de 25 °C y  masa de adsorbente de 100 mg. 

  10. Volumetric and superficial characterization of carbon activated; Caracterizacion volumetrica y superficial de carbon activado

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    Carrera G, L.M.; Garcia S, I.; Jimenez B, J.; Solache R, M.; Lopez M, B.; Bulbulian G, S.; Olguin G, M.T. [Departamento de Quimica, Gerencia de Ciencias Basicas, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    The activated carbon is the resultant material of the calcination process of natural carbonated materials as coconut shells or olive little bones. It is an excellent adsorbent of diluted substances, so much in colloidal form, as in particles form. Those substances are attracted and retained by the carbon surface. In this work is make the volumetric and superficial characterization of activated carbon treated thermically (300 Centigrade) in function of the grain size average. (Author)

  11. Preparación de carbón activado a partir de cáscara de naranja por activación química. caracterización física y química

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    Karen Peña; Liliana Giraldo; Juan Carlos Moreno

    2013-01-01

    Se preparan carbones activados por pirólisisde cáscara de naranja, residuoslignocelulósicos, por activación químicamediante impregnación con solucionesde ácido fosfórico a diferentes concentraciones(32 %, 36 %, 40 % y 48 %p/V), a una temperatura de 373 K y untiempo de residencia de 3 h, presentandorendimientos alrededor del 36 %. Lacaracterización de la textura porosa delos carbones activados obtenidos se determinapor adsorción física de N2 a 77K. El análisis isotérmico muestra paralos carbon...

  12. Adsorción de Fenol y 3-Cloro Fenol sobre Carbones Activados mediante Calorimetría de Inmersión Adsorption of Phenol and 3-Chlorophenol n Activated Carbons using Immersion Calorimetry

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    Moreno-Piraján, Juan C.; Luisa F Navarrete; Liliana Giraldo; Vanessa García

    2007-01-01

    Se ha determinado la entalpía de inmersión de cinco muestras de carbón activado, obtenidas a partir de diferentes materiales lignocelulósicos, con diferente grado de activación en disoluciones acuosas de fenol y 3-cloro fenol con el fin de caracterizar la interacción sólido-disolución acuosa, obteniéndose valores entre 6.80 y 13.9 Jg-1. Se determinó también, las entalpías de inmersión de estos carbones activados en disoluciones de NaOH y HCl 0.1 M, obteniéndose los más altos valores de la ent...

  13. Remoción de colorantes sintéticos mediante el proceso Fenton heterogéneo usando Fe2O3 soportado en carbón activado obtenido a partir de residuos de rosas

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    María Paula Castellanos

    2012-12-01

    Full Text Available To study the removal of dyes:reactive black 5 and crystal violet by the Fenton reaction using Fe2O3-catalysts (0-10% m/m of Fe supported on activated carbon obtained from rose remnants. The activated carbon was obtained from pyrolysis at 500 °C (1h followed by activation with NaOH (1:2 wt.. The support was classified using several chemical and physical techniques. Fe-catalysts were synthesized by incipient impregnation. Fenton and adsorption treatments were performed in a batch reactor, concentration of dye of 10 mgL-1, 0.25 mgmL-1 catalyst, pH = 3.7, 20 ± 2 ° C, 750 rpm and atmospheric pressure. The activated carbon used as support showed high basicity, presence of polar groups on the surface, high ash content (22.85% and oxygen (43.93% and was mostly of the microporous type with a BET surface area of 520 m2g-1. The maximum discoloration achieved for black reactive 5 was obtained with the catalyst of 3% Fe (98.33% after 180 min. while for the crystal violet it was obtained with the catalyst of 1% Fe (63.95% after 180 min. Discoloration by Fenton treatment is dependent on the Fe content, the particle size of the active site and the type of dye. The removal of reactive black 5 reached a maximum at 3% Fe while the crystal violet decreased by increasing Fe content. The treatment proposed in this paper is promising for the removal of synthetic dyes present in contaminated water.

  14. PREPARACIÓN DE CARBÓN ACTIVADO A PARTIR DE CÁSCARA DE NARANJA POR ACTIVACIÓN QUÍMICA. CARACTERIZACIÓN FÍSICA Y QUÍMICA

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    Karen Peña

    2013-08-01

    Full Text Available Se preparan carbones activados por pirólisisde cáscara de naranja, residuoslignocelulósicos, por activación químicamediante impregnación con solucionesde ácido fosfórico a diferentes concentraciones(32 %, 36 %, 40 % y 48 %p/V, a una temperatura de 373 K y untiempo de residencia de 3 h, presentandorendimientos alrededor del 36 %. Lacaracterización de la textura porosa delos carbones activados obtenidos se determinapor adsorción física de N2 a 77K. El análisis isotérmico muestra paralos carbones materiales activados obtenidosáreas superficiales entre 940 y 1200m2g–1 con características de materialesmesoporosos. El estudio mediante técnicasde equilibrio como las titulacionestipo Boehm y la determinación del fósfororesidual, así como técnicas espectroscópicascomo el infrarrojo (IR permitenobservar cómo la variación en la concentracióndel agente activante muestra unainfluencia sobre la química superficialdel material carbonoso a obtener.

  15. INFLUENCIA DE LA COMPOSICIÓN QUÍMICA SUPERFICIAL DEL CARBÓN ACTIVADO EN LA ADSORCIÓN DE BENZOTIAZOLES INFLUENCE OF ACTIVATED CARBON CHEMICAL SURFACE COMPOSITION ON THE ADSORPTION OF BENZOTHIAZOLES

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    Héctor Valdés

    2010-04-01

    Full Text Available Los benzotiazoles están esparcidos en el ambiente debido a su gran variedad de aplicaciones. Dentro de ellos, el benzotiazol (BT, el 2-hidroxibenzotiazol (OHBT, y el 2-metilbenzotiazol (MeBT son conocidos como agentes tóxicos y poco biodegradables. La adsorción con carbón activado se plantea como una opción atractiva para la remoción de estos contaminantes. Sin embargo, existen dudas acerca del efecto de las propiedades químicas superficiales del carbón activado sobre la capacidad de adsorción de estos compuestos. Para el estudio se utilizó carbón activado granular Filtrasorb-400 modificado con el objetivo de obtener carbones con diferentes propiedades químicas superficiales. Las series de carbones activados fueron obtenidas por pretratamiento por desoxigenación y por oxidación con ozono a diferentes tiempos de contacto. El incremento en la concentración de los grupos oxigenados superficiales produce una disminución en la capacidad de adsorción de los tres contaminantes ensayados. Los resultados sugieren que el mecanismo de adsorción transcurre principalmente a través de las interacciones de dispersión π-π entre los electrones del plano basal del carbón y el anillo aromático de los benzotiazoles. A valores de pH mayores al valor del pH de carga cero de la superficie del carbón activado (pH PZC, la capacidad de adsorción del carbón activado disminuye debido a la aparición de interacciones electrostáticas repulsivas entre los grupos superficiales oxigenados ionizados y las moléculas ionizadas de los benzotiazoles.Benzothiazoles, such as benzothiazole (BT, 2-hydroxybenzothiazole (OHBT, and 2-methylbenzothiazole (MeBT are toxic and poorly biodegradable organic compounds, frequently present in wastewater from rubber related applications. Activated carbon adsorption has been identified as an attractive treatment to removing those contaminants. This paper presents experimental results on the effect of chemical surface

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

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    Liliana Giraldo

    2008-03-01

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

  17. PREPARACIÓN DE CARBONES ACTIVADOS A PARTIR DE MATERIALES TEJIDOS Y CARACTERIZACIÓN ESTRUCTURAL POR ADSORCIÓN Y DIFRACCIÓN DE RAYOS X

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    Giovanny Rodriguez

    2008-04-01

    Full Text Available Se preparan telas de carbón activado, a partir de dos materiales tejidos de algodón, por activación química mediante impregnación en soluciones acuosas diluidas de ZnCl2, AlCl3 y H3PO4 y la posterior carbonización en atmósferas de nitrógeno y dióxido de carbono hasta una temperatura final de 850 °C. Se presentan los porcentajes de contracción y rendimiento así como los parámetros estructurales determinados por adsorción de N2 77 K, y se comparan con algunos parámetros cristalográficos determinados por difracción de rayos X. Las telas de carbón activado preparadas presentan áreas superficiales de 210 m2g-1 y 951 m2g-1 así como volúmenes de microporo de 0,09 cm3g-1 y 0,528 cm3g-1que permiten estudiar la influencia de los materiales de partida, el agente químico utilizado en la impregnación y la atmósfera de carbonización.

  18. The effect of the oxygen dissolved in the adsorption of gold in activated carbon; Efecto del oxigeno disuelto en la adsorcion de oro en carbon activado

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    Navarro, P. [Universidad de Santiago. Chile (Chile); Wilkomirsky, I. [Universidad de Concepcion. Chile (Chile)

    1999-07-01

    The effect of the oxygen dissolved on the adsorption of gold in a activated carbon such as these used for carbon in pulp (CIP) and carbon in leach (CIL) processes were studied. The research was oriented to dilucidate the effect of the oxygen dissolved in the gold solution on the kinetics and distribution of the gold adsorbed in the carbon under different conditions of ionic strength, pH and gold concentration. It was found that the level of the oxygen dissolved influences directly the amount of gold adsorbed on the activated carbon, being this effect more relevant for low ionic strength solutions. The pH and initial gold concentration has no effect on this behavior. (Author) 16 refs.

  19. Removal of surfactants from water by adsorption on activated carbon and advanced oxidation process; Eliminacion de surfactantes de las aguas mediante adsorcion sobre carbon activado y oxidacion avanzada

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    Mendez Diaz, J. D.; Sanchez Polo, M.; Rivera Utrilla, J.; Bautista, M. I.

    2007-07-01

    The objective of this study was to analyze the elimination process of surfactants from water, using sodium dode-cilbencenesulfonate (SDBS) as model compound, by means of adsorption on activated carbons as well as different processes of advanced oxidation (O{sub 3}, O{sub 3}/H{sub 2}O{sub 2} and O{sub 3}/activated carbon). Results obtained have shown that the activated carbons used have a high efficiency to eliminate SDBS from waters which was enhanced when the adsorption process was carried out in the presence of bacteria. With regard to the oxidation processes studied, the results have indicated that the efficiency in the elimination of SDBS from water of the system based on the simultaneous use of O{sub 3} and powder activated carbon (PAC) is much higher than those of the other systems studied (O{sub 3},O{sub 3}/H{sub 2}O{sub 2}). (Author) 15 refs.

  20. Aplicación del Modelo de Bohart y Adams en la Remoción de Mercurio de Drenajes de Minería por Adsorción con Carbón Activado Application of the Bohart and Adams Model in the Removal of Mercury from Mine Drainage by Adsorption with Activated Carbon

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    Hugo A Rojas

    2012-01-01

    Full Text Available Se aplica el modelo de Bohart y Adams al proceso de remoción de mercurio de los drenajes de minería por adsorción con carbón activado en columnas de lecho fijo. Para ello se analizaron diferentes drenajes de minas de carbón de Guachetá en Colombia y se simularon en el laboratorio las condiciones reales de vertido de los drenajes. Establecidas las condiciones de funcionamiento óptimo de la columna, se realizó un estudio detallado de curvas de ruptura, a través del modelo de Bohart y Adams, para determinar la vida útil del material adsorbente y la efectividad del método para la remoción del ion metálico. Se estableció que el tiempo de ruptura es de 20 min. y que la columna con el mejor rendimiento tiene 1.7 cm de diámetro y 2 cm de altura del lecho, bajo las condiciones de estudio. El modelo usado describió la parte inicial de la curva de ruptura y los parámetros obtenidos permitieron diseñar y optimizar el funcionamiento de sistemas de adsorción en lecho fijo para la remoción de iones Hg²+ de efluentes acuosos.The model of Bohart and Adams was applied to the process of removal of mercury from mine drainage by adsorption with activated carbon in fixed bed columns. For this several drains from coal mines of Guachetá in Colombia, were studied. Once the optimum operating conditions of the column are established, a detailed study of breakthrough curves using the Bohart and Adams model was done, to determine the lifetime of the adsorbent material and the effectiveness of the method for removal the metal ions. It was established that the breakthrough time was 20 min. and the column with the best performance was 1.7 cm in diameter and 2 cm bed length, under the study conditions. The model described the initial part of the breakthrough curve and the parameters of the model allow designing and optimizing the performance of fixed bed adsorption systems for the removal of Hg²+ ions fro aqueous mine wastes.

  1. Evaluación del Peróxido de Hidrógeno en la Oxidación de Fenol con Hierro Soportado Sobre Tela de Carbón Activado Evaluation of the Hydrogen Peroxide in the Oxidation of Phenol with Iron Supported on Activated Carbon Cloth

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    Juan C Moreno

    2007-01-01

    Full Text Available Se estudia el empleo de una tela de carbón activado comercial, un carbón activado americano y un carbón activado químicamente con KOH, para obtener un material como soporte catalítico mediante impregnación de hierro en solución, para la degradación catalítica de fenol con peróxido de hidrógeno (degradación Fenton. La oxidación se realizó a 42°C, pH entre 2.0-2.5, a presión atmosférica, una concentración inicial de fenol de 0.01064M y 0.89M de H2O2. Se logra una relación de impregnación de 1,39g Fe/gCA sobre la tela de carbón activado. Durante la oxidación del fenol, se siguió el consumo de H2O2, como una medición indirecta de la cinética alcanzándose una concentración mínima de 0.002M de H2O2 por la tela y por el carbón activado americano. El trabajo muestra que la tela de carbón activado como soporte catalítico en la descomposición de fenol es aceptable y competitiva con otros materiales porosos convencionales.This study presents the generation and evaluation of three different materials containing activated carbon and iron for the heterogeneous Fenton degradation of phenol. Three different materials: (i commercial cloth containing activated carbon, and (ii pellet activated carbon and (iii a chemically activated carbon with KOH, were explored to support iron by means of impregnation. These three materials were used for the catalytic degradation of phenol with H2O2. The oxidation was performed at 42°C, pH between 2,0-2,5, atmospheric pressure, an initial phenol concentration of 0,01064M and H2O2 0.89M. A relation of impregnation of 1,39gFe/gAC is obtained on the activated carbon cloth. During the oxidation of phenol, the disappearance of the H2O2 was followed as an indirect indication of the kinetics, reaching a minimal concentration of 0.002M of H2O2 by the cloth and the pellet activated carbon. The study shows that the use of cloth activated carbon as catalytic support for the decomposition of phenol is

  2. Sorption of a phenols mixture in aqueous solution with activated carbon; Sorcion de una mezcla de fenoles en solucion acuosa con carbon activado

    Energy Technology Data Exchange (ETDEWEB)

    Mejia M, D

    2004-07-01

    The constant population growth and the quick industrialization have caused severe damages to our natural aquifer resources for a great variety of organic and inorganic pollutants. Among these they are those phenol compounds that are highly toxic, resistant (to the degradation chemistry) and poorly biodegradable. The phenolic compounds is used in a great variety of industries, like it is the production of resins, nylon, plastifiers, anti-oxidants, oil additives, drugs, pesticides, colorants, explosives, disinfectants and others. The disseminated discharges or effluents coming from the industrial processes toward lakes and rivers are causing a growing adverse effect in the environment, as well as a risk for the health. Numerous studies exist on the phenols removal and phenols substituted for very varied techniques, among them they are the adsorption in activated carbon. This finishes it has been used successfully for the treatment of residual waters municipal and industrial and of drinking waters and it is considered as the best technique available to eliminate organic compounds not biodegradable and toxic present in aqueous solution (US EPA, 1991). However a little information exists on studies carried out in aqueous systems with more of a phenolic compound. The activated carbon is broadly used as adsorbent due to its superficial properties in the so much treatment of water as of aqueous wastes, adsorbent for the removal of organic pollutants. The main objective of this work is the adsorption of a aqueous mixture of phenol-4 chloro phenol of different concentrations in activated carbon of mineral origin of different meshes and to diminish with it their presence in water. The experiments were carried out for lots, in normal conditions of temperature and pressure. The experimental results show that the removal capacity depends so much of the superficial properties of the sorbent like of the physical properties and chemical of the sorbate. The isotherms were carried

  3. Sorption of a mixture of phenols in aqueous solution with activated carbon; Sorcion de una mezcla de fenoles en solucion acuosa con carbon activado

    Energy Technology Data Exchange (ETDEWEB)

    Mejia M, D.; Lopez M, B.E.; Iturbe G, J.L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    The main objective of this work is the sorption of an aqueous mixture of phenol-4 chloro phenol of different concentrations in a molar relationship 1:1 in activated carbon of mineral origin of different nets (10, 20 and 30) and to diminish with it its presence in water. The experimental results show that the removal capacity depends so much of the surface properties of the sorbent like of the physical and chemical properties of the sorbate. In all the cases it was observed that in the aqueous systems of low concentration the 4-chloro phenol are removed in an approximate proportion of 1.2-4 times greater to than phenol, however to concentrations but high both they are removed approximately in the same proportion. (Author)

  4. Effect of the physical properties of activated carbon in the gold adsorption from cyanide media; Efecto de las propiedades fisicas del carbon activado en la adsorcion de oro desde medio cianuro

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, P.; Vargas, C.

    2010-07-01

    The effect of the physical properties of an activated carbon such as pore size distribution, specific surface, pore average diameter, in the gold adsorption from cyanide solution with the gold to the Au (CN){sup -}{sub 2} form, was studied. To meet the proposed objectives two carbons were studied: carbon A with specific surface of 985 m{sup 2} / g, 57 % of micropores and 1.85 nm as average diameter of pores and carbon B with specific surface of 786 m{sup 2} / g, 27 % and pores of 2.35 nm as average diameter of pores; both granular carbons made from coconut shell. Batch adsorption tests were performed in a reactor of 500 ml of capacity with mechanical stirring at constant temperature. The effect of cations present in the aqueous solutions such as Ca{sup 2}+, Na+, K+ and Li+, the effect of pore size distribution, the effect of average pore diameter and surface area were evaluated in function of the rate and amount of gold adsorbed on the activated carbons denominated as A and B. The results to indicate that the physical properties of an activated carbon are an important factor in the gold adsorption process in terms of rate and amount of adsorbed gold. The carbon B with 786 m{sup 2} / g of specific surface area reached a higher load per unit area (0.02 mg Au/m{sup 2}) in relation to the carbon B of 985 m{sup 2} / g which had a load of 0.01 mg Au / m{sup 2}, after 6 h of contact carbon-solution. The rate adsorption of gold in both carbons is controlled by mass transfer in the liquid film surrounding the carbon particles to short times or small loads of gold in the particles, far from equilibrium. Applying a first order kinetic model, it was obtained that the ratio of the kinetic constants for carbons A and B, ie (kB / kA), fluctuates in a value of 3 for the different cations in study. In general it is possible to say that the rate adsorption and the amount of adsorbed gold increased with the increase in macropores and with the increasing pore average diameter. The

  5. Final report of the project 'Regeneration of activated carbon used in residual water treatment plants'; Informe final del proyecto 'Regeneracion de carbon activado usado en plantas de tratamiento de aguas residuales'

    Energy Technology Data Exchange (ETDEWEB)

    Martinez M, I.; Hernandez M, V

    1992-01-15

    Among the new methods used to reactivate carbon, its are the one that uses infrared light and the one that uses accelerated electrons. The technology in both processes is novel, the energy is used but efficiently, it doesn't get lost but of 5% of carbon and its are less polluting. This report presents the one method and results obtained in the irradiation of coal. (Author)

  6. Influence of the particle size of activated mineral carbon on the phenol and chlorophenol adsorption; Influencia del tamano de particula de carbon mineral activado sobre la adsorcion de fenol y clorofenol

    Energy Technology Data Exchange (ETDEWEB)

    Garcia M, A

    2001-07-01

    Water pollution by phenolic compounds is a problem that requires a solution since these phenolic compounds are not completely biodegradable, they accumulate through the food chains and they are quite toxic when enter in contact with living organisms. In human beings, ingestion or contact of the skin with this type of compounds produces irritation and damages mainly to the liver and kidneys. In fact, the Environmental Protection Agency of the United States (EPA assigned nine phenolic compounds among the 275 most toxic substances in 1991. Phenols are found in wastewater from agriculture and industry, because phenolic compounds are used as pesticides and in diverse industrial activities. The treatment of this type of water is not simple because they are generally composed of a mixture of residuals with different chemical nature A useful method for the removal of phenols is the adsorption by activated carbon, since this material has a great surface area and it can be regenerated. The adsorption process depends, among other factors, on the activated carbon characteristics. When they are modified, their capacity to remove pollutants from the water changes. The effect of activated carbon particle size on the removal of phenolic compounds has not been completely studied. Therefore, the aim of this work was to determine the influence of the mineral activated carbon particle size on the phenol and 4-chloro phenol adsorption in aqueous solution, on adsorption column system. The results of the present work indicate that the mineral activated carbon particle size has a very important influence on the adsorption of phenol and 4-chloro phenol. When the particles were smaller, the retention quantities of phenol and 4-chloro phenol increased. This behavior was related to the particle characteristics of the mineral activated carbon such as surface area and pore volume, while other factors such as elementary composition of the activated carbon did not influence the adsorption process

  7. Oxidación de cianuro en disolución acuosa mediante ozonización en presencia de carbón activado modificado

    Directory of Open Access Journals (Sweden)

    M. A. Sánchez Castillo

    2013-01-01

    Full Text Available El objetivo de este trabajo fue analizar el papel quedesempeña el carbón activado en el proceso deozonización del anión cianuro. Los resultadosobtenidos muestran que el carbón activadopreviamente tratado con amoniaco incrementóconsiderablemente la velocidad de eliminación delanión cianuro. Los resultados obtenidos medianteFTIR y XPS muestran un incremento en laconcentración de grupos carbonilo, los cuales conla interacción con el ozono podrían potenciar lageneración de radicales altamente oxidantes en elmedio justificándose así los resultados obtenidos.

  8. Removal of pharmaceutical compounds from water by adsorption on activated carbon and degradation with ozone; Eliminacion de compuestos farmaceuticos de las aguas por adsorcion en carbon activado y degradacion con ozono

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Polo, M.; Prado Joya, G.; Rivera Utrilla, J.; Ferro Garcia, M. A.; Bautista Toledo, M. I.; Lopez Penalver, J. J.; Gomez Merlo de la fuente, C.

    2007-07-01

    The removal of pharmaceutical compounds from water, using nitroimidazoles as model compounds, by means of both adsorption on activated carbon and ozonization has been studied. The results obtained have shown that activated carbon presents a great efficiency to remove these contaminants from waters because: the adsorption kinetics is very fast, and it is not affected by diffusion problems; the maximum adsorption capacity is very high (400-96 mg/g); and the nitroimidazole adsorption capacity is enhanced in natural waters. Regarding to the ozonization process, a low reactivity of these compounds with ozone has been observed (k{sub 0}3{approx_equal}100 M{sup -}1 s{sup -}1) although, nevertheless, they present a high affinity to the hydroxyl radicals (k{sub O}H{approx_equal}10{sup 1}0 M{sup -}1s{sup -}1). (Author) 13 refs.

  9. Estudio cinético de la descomposición catalizada de peróxido de hidrógeno sobre carbón activado Kinetic study of the catalyzed decomposition of hydrogen peroxide on activated carbon

    Directory of Open Access Journals (Sweden)

    Elihu Paternina

    2009-01-01

    Full Text Available The kinetic study of decomposition of hydrogen peroxide catalyzed by activated carbon was carried out. The effect of concentrations of reactants and temperature were experimentally studied. Kinetic data were evaluated using differential method of initial rates of reaction. When a typical kinetic law for reactions in homogeneous phase is used, first order of reaction is obtained for hydrogen peroxide and activated carbon, and activation energy of 27 kJ mol-1 for the reaction was estimated. Experimentally was observed that surface of activated carbon is chemically modified during decomposition of hydrogen peroxide, based on this result a scheme of reaction was proposed and evaluated. Experimental data fits very well to a Langmuir- Hinshelwood kinetic model and activation energy of 40 kJ mol-1 was estimated for reaction in heterogeneous phase.

  10. Efecto del carbón activado y ácido indol acético en el desarrollo de protocormos de Masdevallia coccinea Linden ex Lindl. y Maxillaria nutans Lindl.. In vitro

    Directory of Open Access Journals (Sweden)

    Jaime Alonso Pedroza-Manrique

    2010-10-01

    Full Text Available Título en inglés: Effect of activated charcoal indol and acetic acid in the development of Masdevallia coccinea Linden ex Lindl y Maxillaria nutans Lindl. protocorm like bodies under in vitro. Resumen En esta investigación se pretende estimular el desarrollo de protocormos de Masdevallia coccinea y Maxillaria nutans bajo condiciones in vitro utilizando diferentes concentraciones de ácido indol acético y carbón activado. El protocolo obtenido es una alternativa de la conservación de orquídeas que se encuentran en vías de extinción, y además permite contribuir con el mejoramiento medioambiental. En la evaluación del desarrollo vegetativo bajo condiciones in vitro de los protocormos de Masdevallia coccinea y Maxillaria nutans, orquídeas en vías de extinción, se obtuvo que solamente Maxillaria nutans alcanzará su desarrollo exitoso mediante el cultivo in vitro en el medio Murashige y Skoog (1962, donde se evaluó el efecto de la interacción entre el carbón activado (0,0; 0,5, 1,0 % (p/v y el ácido indol acético (0,0; 0,5; 1,0 mg/L-1. El medio de cultivo empleado fue enriquecido con sacarosa al 3% y el Myo inositol al 0,1 g/L-1. Los protocormos de Masdevallia coccinea evidenciaron que se encontraban inmaduros, situación por la cual no lograron su desarrollarlo vegetativo en el experimento planteado, en atención a que se encontraban en el periodo de latencia. Por esta razón, es de gran importancia tener en cuenta que las cápsulas de las orquídeas deben estar bien maduras, a fin de garantizar que los protocormos que se forman in vitro sean maduros y completen con facilidad su morfofisiológía. Mientras que los protocormos de Maxillaria nutans dieron un mayor rendimiento en su desarrollo vegetativo. En esta investigación se determinó que el efecto de la interacción de 0,5% de carbón activado con 0,5 mg/L-1 de AIA es positivo sobre la tasa de crecimiento para el desarrollo de los protocormos de Maxillaria nutans bajo

  11. MONOLITOS DE CARBÓN ACTIVADO A PARTIR DE CÁSCARA DE COCO E IMPREGNACIÓN CON NIQUEL Y COBRE

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2009-04-01

    Full Text Available Una serie de diferentes monolitos de carbón activado fueron preparados a partir de cáscara de coco por medio de activación química con ácido fosfórico a diferentes concentraciones sin utilizar aglomerantes ni plastificantes. Al monolito que mayor área desarrolló se le impregnó vía húmeda con soluciones de Ni y Cu a diferentes relaciones molares. Las estructuras fueron caracterizadas por la adsorción de N2 a 77 K, y se exploró su morfología por medio de microscopía electrónica de barrido. Los materiales carbonosos obtenidos, níquel-cobre-monolito, fueron analizados por Reducción Térmica Programada (RTP. Los resultados experimentales indicaron que la activación con ácido fosfórico genera una microporosidad, con volúmenes de microporos entre 0,39  y 0,81 cm3g-1 y áreas superficiales entre 703 y 1450 m2g-1, y buenas propiedades mecánicas. Se muestra que tanto el cobre como el níquel se fijan al monolito y se interpretan los resultados de RTP respecto a cuándo se modifica su relación molar.

  12. Caracterización del proceso de adsorción de 3-cloro fenol desde solución acuosa sobre carbon activado por calorimetria de inmersión Characterization of 3-chlorophenol adsorption process from aqueous solution on activated carbon by immersion calorimetry

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2009-01-01

    Full Text Available The immersion enthalpy of activated carbon in 3-chlorophenol solutions, of 100 mg L-1, is determined at different pH values between 3 and 11 with results between 37.6 and 21.2 J g-1. The 3-chlorophenol adsorbed quantities on the activated carbon during the calorimetric experience, are between 1.13 and 2.19 mg g-1, for different pH values of the solution. The 3-chlorophenol adsorbed quantity and the immersion enthalpy decrease by increasing of the pH solution, while increasing the adsorbed quantity increases the immersion enthalpy value.

  13. Efecto de las propiedades físicas del carbón activado en la adsorción de oro desde medio cianuro

    Directory of Open Access Journals (Sweden)

    Navarro, P.

    2010-06-01

    amount of adsorbed gold increased with the increase in macropores and with the increasing pore average diameter. The presence of cations favors the gold adsorption in cyanide media, especially those of higher valence.

    Se estudió el efecto de las propiedades físicas de un carbón activado, tales como distribución de tamaño de poros, superficie específica, diámetro promedio de poros, en la adsorción de oro desde disoluciones cianuradas, con el oro disuelto a la forma de Au (CN2. Para cumplir con los objetivos planteados se trabajó con dos carbones activados: el carbón A, con superficie específica de 985 m2/g, 57 % de microporos y 3,8 nm como diámetro promedio de poros, y el carbón B, con superficie específica de 786 m2/g, 27 % de microporos y 11,6 nm como diámetro promedio de poros; ambos carbones, de forma granular, han sido fabricados a partir de cáscara de coco. Se realizaron ensayos de adsorción batch en un reactor de 500 ml de capacidad, con agitación mecánica a temperatura constante. Se estudiaron los efectos de cationes presentes, tales como Ca2+, Na+, K+ y Li+, de la distribución de tamaño de poros, del diámetro promedio de poros y del área superficial, en la velocidad y cantidad de oro adsorbido en los carbones activados denominados como A y B. Se encontró que las propiedades físicas de un carbón activado constituyen un factor relevante en el proceso de adsorción de oro, en términos de velocidad y cantidad de oro adsorbido. El carbón B, con 786 m2/g de superficie específica, alcanzó una mayor carga por unidad de superficie (0,02 mg Au/m2 en relación al carbón A, de 985 m2/g, el cual alcanzó una carga de 0,01 mg Au/m2, después de 6 h de contacto carbón-disolución. La velocidad de adsorción de oro en ambos carbones fue controlada por transferencia de masa en la película líquida que rodea

  14. Recuperación de oro a partir de disoluciones de amoniaco y tiosulfato utilizando carbón activado

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    Vargas, C.

    2006-06-01

    Full Text Available The recovery of gold from solutions containing thiosulfate and ammonia using granular activated carbon was studied, evaluating the adsorption and elution stages. The influence of ammonia and thiosulfate concentration and the presence of impurities such as copper and zinc were also evaluated. In the presence of ammonia there was a concentration which maximized the adsorption of gold, while thiosulfate and impurities presence was harmful for the adsorption of gold. During elution, ammonia and thiosulfate concentration, pH regulator and temperature were evaluated. Ammonia favored the process as long as thiosulfate showed a maximum starting from which the elution diminishes. The effect of the pH regulator was very important; If was revealed that when the pH was regulated with caustic ammonia, a synergic effect appeared which favored the elution. Temperature favored the elution process, with activation energy of 9.13 kJ/mol.

    Se estudió la recuperación de oro de disoluciones de tiosulfato y amoniaco, utilizando carbón activado en gránulos, evaluando las etapas de adsorción y desorción. En la etapa de adsorción se evaluaron la concentración de amoniaco, de tiosulfato y de impurezas como cobre y cinc. En las condiciones experimentales ensayadas se encontró que, en presencia de amoniaco, existe una concentración óptima que maximiza la adsorción de oro, mientras que la presencia de tiosulfato e impurezas, tales como cobre y cinc, es perjudicial para la adsorción de oro. Para la desorción se evaluó la concentración de amoniaco, de tiosulfato, el regulador de pH y la temperatura. El amoniaco favoreció el proceso, en tanto que el tiosulfato presentó un máximo a partir del cual la desorción disminuyó. El efecto del regulador de pH fue muy importante, determinándose que cuando el pH era controlado con hidróxido de amonio, se presentaba un efecto sinérgico que favorecía la desorción. La temperatura favoreció el proceso de

  15. REACCIONES CON TEMPERATURA PROGRAMADA ENTRE EL METANO Y CARBÓN ACTIVADO OXIDADO

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    Laura R. Conde

    2008-09-01

    Full Text Available Se realizaron reacciones en ausencia de O2, entre mezclas de CH4 con He y carbón activado oxidado, haciendo un barrido continuo de temperaturas. Se observó la presencia de tres tipos de reacciones: a baja temperatura formación agotable de etileno,  a temperatura media la formación de CO, CO2, H2O, C3H8 y C4H10 que cesaron al incrementar la temperatura de reacción, y a temperatura alta se formaron C2H4 y C2H6 que se mantuvieron al incrementar la temperatura de trabajo. Se discuten dos mecanismos de reacción: uno que podría explicar la formación agotable de C2H4, C3H8 y C4H10, y otro que podría explicar la formación sostenida de C2H4 y C2H6. Los resultados evidencian la posibilidad de valorización simultánea de metano y carbón.

  16. Bioindicadores en los reactores de fangos activados en la EDAR Guadalete : técnica para controlar su funcionamiento

    OpenAIRE

    Narbona Valle, Eva María; Isac Oria, Laura; Lebrato Martínez, Julián; Martínez, Ángel

    2000-01-01

    Artículo original escaneado para el Repositorio (archivo delegado) La bioindicación, técnica basada en la observación microscópica del fango activo, es una herramienta útil para el control de los procesos de depuración biológica. Se pretende demostrar la efectividad de esta técnica mediante su aplicación en el estudio de un sistema de fangos activados estable, sin cambios bruscos en sus parámetros operacionales. Algunos de los microorganismos observados servirán de indicadores del estado ...

  17. Estado de conocimiento sobre los procesos de sorción de PPCPs en barros activados

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    Enrique A Campanella

    2013-06-01

    Full Text Available Los farmacéuticos y productos de cuidado personal (PPCPs pertenecen al grupo contaminantes emergentes, su riego ambiental no se había detectado hasta hace una década. Recientemente, han sido reportados de causar efectos adversos sobre la vida silvestre y humana. Además, la mayoría de estos compuestos derivan en plantas de tratamiento de aguas residuales, donde pueden sufrir procesos de biodegradación, sorción en biomasa o stripping.Muchas investigaciones relevantes han sido realizadas para el estudio de la degradación de PPCPs, no obstante, la información sobre el proceso de sorción es limitada. Por lo tanto, es objetivo de este trabajo resumir el estado de conocimiento sobre el tema, a los efectos de establecer su estado actual y aclarar necesidades en materia de investigación y direcciones.La inspección del material disponible arroja resultados positivos relacionados al entendimiento de los mecanismos involucrados. Sin embargo, se ha determinado que la sorción de muchos PPCPs en la biomasa no es ideal, sino un proceso relativamente complejo. Como resultado de esta complejidad los modelos simplificados propuestos no logran una descripción completa, más aún, la predicción del particionado ambiental no es suficientemente precisa en algunos casos.Un estudio más detallado del proceso de adsorción de PPCP en barros activados es necesario para mejorar los modelos propuestos en diversos trabajos y optimizar la predicción del particionado. La información de la sorción de PPCP, sus metabolitos, y la competencia entre ellos, aún no es suficiente para ser incorporada en dichos modelos.

  18. Preparación y caracterización de carbón activado granular obtenido a partir de cuesco de palma africana (Elaeis Guineensis) para la adsorción de CO2

    OpenAIRE

    Acevedo Corredor, Sergio Alberto

    2014-01-01

    Uno de los problemas ambientales de importancia en las últimas décadas ha sido la contaminación del aire, ya que las principales causas que originan dicha contaminación se generan principalmente por actividades de tipo industrial, domesticas, comerciales y agropecuarias. Dichas actividades han incrementado la cantidad de CO2 liberado a la atmósfera y por ende los efectos que produce sobre el cambio climático, que enfatiza la importancia en procesos orientados a su captura. L...

  19. Carvões activados para a remoção de compostos farmacêuticos em meio aquoso

    OpenAIRE

    Cabrita, Ivânia Raquel Costa

    2009-01-01

    Tese de mestrado, Química Tecnológica, Universidade de Lisboa, Faculdade de Ciências, 2009 Neste trabalho foi investigado o uso de carvões activados para a remoção de paracetamol em meio aquoso, usando adsorventes disponíveis comercialmente, modificados quimicamente. Foi também usado um carvão obtido da activação de desperdícios de PET.A capacidade de adsorção dos carvões foi relacionada com as suas propriedades texturais e químicas. A natureza química dos materiais foi modificada por oxid...

  20. Remoção do fenol em solução aquosa por adsorção em carvão activado

    OpenAIRE

    Daniel, Carla Isabel Lopes

    2009-01-01

    Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção de grau de Mestre em Engenharia Química e Bioquímica O objectivo deste trabalho foi estudar o efeito das propriedades texturais e químicas da superfície do carvão activado, na adsorção de fenol em fase aquosa. Os carvões activados usados como adsorventes foram preparados a partir de diversos precursores após activação com vapor de água. Alguns carvões foram modificados por im...

  1. Análisis de las variables que afectan el desarrollo de microorganismos filamentosos en sistemas de barros activados para el tratamiento de efluentes de la industria alimenticia

    OpenAIRE

    Contreras, Edgardo

    2001-01-01

    Objetivo general Realizar un estudio comparativo de los parámetros cinéticos y estequiométricos que caracterizan el desarrollo de un microorganismo filamentoso y uno floculante con el objeto de hallar las condiciones operativas que permitan controlar la aparición de bulking debido al desarrollo excesivo de microorganismos filamentosos en sistemas de tratamiento de efluentes de la industria procesadora de vegetales por barros activados. A tal efecto se utilizará Sphaerotilus natans como mi...

  2. Obtención del carbón activado a partir de residuos de madera de la industria mueblera del estado de Aguascalientes

    Directory of Open Access Journals (Sweden)

    J. Rosario Rivera Hernández

    2003-01-01

    Full Text Available En la presente investigación se utilizaron tres tipos de residuos de madera, caoba, cedro y pino, como agentes de activación, ácido clorhídrico, ácido sulfúrico, cloruro de calcio y cloruro de zinc a concentraciones de 5, 10, 15 y 20% en peso, luego se aplicaron doce procedimientos experimentales (A, B, C, D, E, F, G, H, I, J, K y L, para obtener 48 muestras de carbón activado a la temperatura de 400 °C y 48 muestras a 700 °C, el tiempo de carbonización que se empleo para cada una de las muestras de residuos de madera fue de 1 hr. En las tablas 1 a 12 aparecen los resultados referentes a la cantidad de carbón activado que se obtuvo en cada procedimiento experimental aplicado, así como en las tablas 13 a 18 se da información de la eficiencia de adsorción con disoluciones de ácido acético, azul de metileno y jabón. La finalidad de este proyecto es la de reducir por una parte la generación de residuos de madera y por otra parte que el carbón activado que se obtenga y bajo pruebas de laboratorio pueda ser aplicado en un futuro en la industria de la región.

  3. Determinación de la entalpía de inmersión de carbón activado en soluciones acuosas de fenol y su relación con la capacidad de adsorción

    OpenAIRE

    Liliana Giraldo G.; Juan Carlos Moreno P.

    2008-01-01

    Se determinan las entalpías de inmersión a 298 K de un carbón activado comercial microporoso en soluciones acuosas defenol en un rango de concentración de 10 a 100 mg L-1, sin control de pH; se obtienen valores entre 15 y 36 J.g-1.Se determina la cantidad de fenol adsorbido en el carbón activado en el mismo rango de concentraciones y se calcula la cantidad adsorbida en la monocapa de 164 mg.g-1.Se establece la relación entre el calor de inmersió...

  4. Hormigón de bajo impacto ambiental elaborado con materiales activados alcalinamente para su uso en firmes compactados con rodillo

    OpenAIRE

    IBORRA BOSCH, PAULA

    2011-01-01

    Convenios con empresa. El objetivo de este trabajo es la evaluación preliminar de la viabilidad técnica de dos formulaciones de hormigón elaboradas con residuos activados alcalinamente para el desarrollo de firmes de carretera compactados a rodillo de bajo impacto ambiental. Para lograr este objetivo, se han seguido las siguientes etapas: obtención de una dosificación optimizada con hormigón convencional, realización de ensayos con las dos formulaciones de hormigón elaboradas con residuos act...

  5. Determinación de la entalpia de inmersión de carbón activado en soluciones acuosas de fenol y su relación con la capacidad de adsorción

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo G.

    2010-10-01

    Full Text Available Se determinan las entalpias de inmersión a 298 K de un carbón activado comercial microporoso en soluciones acuosas de fenol en un rango de concentración de 10 a 100 mg L-1 , sin control de pH; se obtienen valores entre 15 y 36 J.g 1.

  6. Estudio por Drifts de la oxidación en óxido nitroso de un carbón activado

    Directory of Open Access Journals (Sweden)

    José de Jesús Díaz Velásquez

    2011-03-01

    Full Text Available Con el propósito de obtener materiales con propiedades superficiales diversas, en este trabajo se modificó un carbón activado mediante tratamiento térmico en una atmósfera de 20 % de óxido nitroso en nitrógeno a 500°C, por diferentes períodos de tiempo, al igual que en atmósferas de 5% de oxígeno en nitrógeno a 425°C por 600 minutos, y de 100% dehidrógeno a 950°C por 360 minutos. Para caracterizar la química superficial de los materiales tratados, se utilizó latécnica DRIFTS, cuyos resultados cualitativos muestran que los tratamientos con óxido nitroso tienen efectos mayoressobre la intensidad de los grupos superficiales formados. Estos cambios podrían estar asociados con la incorporacióndel nitrógeno dentro de la matriz del carbón. De acuerdo con los reportes de la literatura, la oxidación en fase gaseosadel carbón activado muestra principalmente grupos superficiales, tales como anhídridos carboxílicos, fenoles ycarboxilatos, lactonas y quinonas.

  7. Simulación de un sistema de fangos activados en discontinuo para la eliminación de materia orgánica y nutrientes

    Directory of Open Access Journals (Sweden)

    José Manga

    2003-01-01

    Full Text Available Se ha desarrollado un simulador para el sistema de fangos activados en discontinuo (Sequencing Batch Reactor o SBR, que permite el estudio de los procesos para la eliminación de la materia orgánica y nutrientes. El simulador incluye el modelo Nº 2d de fangos activados (ASM2d propuesto por la International Water Association (IWA. Además, en fase de sedimentación, se incluye un modelo exponencial o de Vesinlind para la separación de los sólidos en suspensión del licor mezcla. La herramienta informática ha sido utilizada para describir el comportamiento de dos sistemas en discontinuo (anaerobio/aerobio y aerobio/ anóxico bajo diferentes condiciones de operación (tiempo de retención celular, tiempo de retención hidráulico, entre otros. Los resultados muestran que la herramienta informática desarrollada puede ser utilizada para el diseño y simulación de sistemas sbr en el tratamiento de aguas residuales.

  8. Preparación, caracterización y aplicaciones de Carbones activados preparados a partir de lignina Kraft.

    OpenAIRE

    Torné Fernández, Vanessa

    2006-01-01

    La creciente demanda de productos altamente purificados requiere el desarrollo tecnológico de métodos de separación cada vez más selectivos y el entendimiento de los procesos físicos y químicos que tienen lugar. Actualmente, los materiales que se usan principalmente en los métodos de separación y purificación son los adsorbentes porosos basados en zeolitas y los de naturaleza carbonosa. En ambos casos, su estructura microporosa permite la separación basada en el tamaño y/o forma de las molécu...

  9. Encuesta sobre los eventos adversos relacionados con el uso de carbón activado en urgencias y emergencias

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    G. Burillo Putze

    2015-08-01

    Full Text Available Fundamento: Existen pocos estudios en España sobre el uso de carbón activado (CA en las intoxicaciones agudas por vía digestiva, y más concretamente sobre su protocolización y eventos adversos tras su administración. Este trabajo tiene como objetivo conocer la experiencia en el uso de CA, por los médicos y enfermeros de los servicios de urgencias y emergencias españoles. Método: Diseño de una encuesta a profesionales sanitarios de urgencias y emergencias, mediante la aplicación informática Google Docs. Resultados: Ser recibieron 364 encuestas, de ellas un 52% procedentes de facultativos. Contestaron realizar sondaje previo al uso de CA el 74,5%, y no utilizar sonda en el 13% de los pacientes. Se consideró correcta la aplicación de CA en un 37,4%, usándose globalmente en un 92,4% de los casos. La posición lateral de seguridad manifestaron usarla el 46,2%, antieméticos el 86,5% y aislaban la vía aérea en caso de coma (GCS<8 el 60%. Los eventos adversos más descritos fueron los vómitos de CA (61%, la epixtasis al colocar la sonda (51,1% y la incorrecta colocación de la misma (36%. La broncoaspiración de vómitos les ocurrió al 11,8% y de carbón al 4,7%. Un 7,1% manifestó que los eventos adversos habían supuesto riesgo vital para los pacientes. No se halló relación entre protocolización de la asistencia y eventos adversos graves o riesgo vital, ni entre éstos y las medidas de seguridad clínica. Conclusiones: La incidencia de eventos adversos, en función de lo manifestado por los profesionales en esta encuesta sobre su práctica clínica, podría ser superior a las que se encuentran en la literatura.

  10. Monolitos de carbón activado a partir de cáscara de coco e impregnación con niquel y cobre

    OpenAIRE

    Liliana Giraldo; Moreno-Piraján, J. C.

    2009-01-01

    Una serie de diferentes monolitos de carbón activado fueron preparados a partir de cáscara de coco por medio de activación química con ácido fosfórico a diferentes concentraciones sin utilizar aglomerantes ni plastificantes. Al monolito que mayor área desarrolló se le impregnó vía húmeda con soluciones de Ni y Cu a diferentes relaciones molares. Las estructuras fueron caracterizadas por la adsorción de N2 a 77 K, y se exploró su morfología por medio de microscopía electrónica de barrido. Los ...

  11. Comparación de la calidad del coque siderúrgico obtenido a diferentes escalas

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    G. Cimadevilla, J. L.

    2005-12-01

    Full Text Available Coke cold mechanical strength measured by means of the IRSID test, reactivity towards CO2 (CRI and post-reaction strength (CSR are the most important parameters for controlling coke quality in Spain. INCAR was running a semi-industrial coking test plant until July of 1999. Previous to this closure, a comparison of the coke quality was made between the 6 t oven of this test plant and a 250 kg movable wall oven (MWO. It is thus possible to use the coke quality data obtained in the 250 kg MWO to predict coke quality at semi-industrial and industrial scales.

    La resistencia mecánica en frío del coque siderúrgico -evaluada mediante el ensayo IRSID-, la reactividad frente al CO2 (CRI y la resistencia mecánica post-reacción (CSR son los parámetros más importantes empleados para controlar la calidad del coque en España. En el INCAR, antes del cierre de la Coquería Experimental en Julio de 1999, se ha realizado un estudio para determinar la correlación existente entre la calidad del coque obtenido a escala semi-industrial -homo de 6 t - y a escala piloto -horno de pared móvil (HPM de 250 kg-. En este trabajo se describen los estudios realizados y los resultados obtenidos, los cuales permiten predecir la calidad del coque que se vaya a obtener a escala industrial a partir de los datos obtenidos en el HPM.

  12. PREPARACIÓN Y CARACTERIZACIÓN DE TELAS DE CARBÓN ACTIVADO. INFLUENCIA DEL MATERIAL PRECURSOR DE ALGODÓN

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    Giovanny Rodríguez

    2008-04-01

    Full Text Available Se preparan dos telas de carbón activado a partir de la activación química de textiles de algodón. La preparación de los materiales se lleva a cabo por medio de la impregnación de éstos en una solución 0,10 M de H3PO4, seguida de una carbonización en atmósfera de dióxido de carbono hasta una temperatura final de 825ËšC. Se presentan los análisis termogravimétricos de las telas de partida que permiten ajustar las condiciones experimentales de carbonización, así como los porcentajes de contracción y rendimiento de los materiales preparados, que se encuentran entre un 50% y 20%, respectivamente.Las telas de carbón activado preparadas presentan  áreas superficiales de 796 m2 g-1 y 951 m2g-1 igual que volúmenes de microporo de 0,416 cm3 g-1 y  0,528 cm3 g-1. Un estudio calorimétrico de los sólidos preparados permite estimar que las entalpías de inmersión en tetracloruro de carbono son -4,66 J g-1 y -5,05 J g-1, respectivamente. Los resultados de un análisis por microscopia óptica de las telas preparadas también son presentados.  

  13. Actividad antibacteriana de soluciones acidas de quitosano obtenido de exoesqueleto de camarón

    OpenAIRE

    Alexander Pérez Cordero; Johanna Rojas Sierra; Johana Rodriguez Ruiz; Irma Arrieta Alvarez; Yenis Arrieta Alvarez; Andrés Rodríguez Carrascal

    2014-01-01

    Título en ingles: Antibacterial activity of chitosan acid solutions obtained from shrimp exoskeleton Título: quitosano actividad antibacterianaResumen: El trabajo tuvo como objetivo evaluar la actividad antibacteriana in vitro de soluciones ácidas de quitosano obtenido a partir del exoesqueleto de camarón, sobre siete bacterias patógenas, cinco de las cuales corresponden a patógenas de humanos (Enterococcus faecalis ATCC 29212, Escherichia coli UDS, Pseudomonas aeruginosa ATCC 27853, Klebsiel...

  14. Normalización automática de registros obtenidos de la Web of Science

    OpenAIRE

    Serrano-López, Antonio Eleazar; Martín Moreno, María del Carmen

    2012-01-01

    Los lenguajes de programación orientados al tratamiento automático de textos ya han demostrado anteriormente su utilidad para procesar y gestionar los registros bibliográficos obtenidos de diferentes bases de datos. Concretamente el lenguaje Perl ha sido utilizado en numerosas metodologías relacionadas con la bibliometría, para extraer los diferentes elementos de los registros bibliográficos, incorporarlos a bases de datos relacionales, procesarlos y obtener de ellos múltiples indicadores. Es...

  15. Carbón activado de semillas de tomate para adsorción de vapores de amoniaco, benceno y gasolina//Activated coal of tomato seeds for adsorption of vapors of ammonia, benzene and gasoline

    Directory of Open Access Journals (Sweden)

    Francisco Márquez-Montesino

    2013-05-01

    Full Text Available El objetivo fue comprobar las posibilidades de adsorción de amoniaco, benceno y gasolina en carbones activados, de semillas de tomate. Se realizó un análisis inmediato a la biomasa. Se concluyó que la adsorción de vapores de amoniaco, está relacionada con la adsorción física y con la presencia de gruposfuncionales de carácter ácido en la superficie activa de los carbones, que forman enlaces débiles con las moléculas de amoniaco. Se realizaron experimentos de adsorción de benceno y gasolina, que no tienen grupos funcionales como el amoniaco, siendo menos adsorbidos, confirmándose una adsorción preferentemente química. La temperatura de activación, la relación de impregnación (RI y laconcentración de la disolución ácida, no tuvieron una influencia significativa en la capacidad de adsorción de benceno, pero sí en la adsorción de amoniaco y vapores de gasolina, de gran aplicación para la eliminación de los vapores de escape en los motores de vehículos.Palabras claves: carbón, activación, adsorción, vapores, amoníaco._______________________________________________________________________________AbstractThe objective was to prove the adsorption possibilities of ammonia, benzene and vapors of gasoline in activated coals with phosphoric acid, of tomato seed. An immediate analysis to the biomass was carried out. It was concluded that the vapors adsorption of ammonia, is related with the physical adsorption andthe presence of functional groups of acid character in the active surface of the coal that form weak connections with the molecules of ammonia. Experiments of adsorption of benzene and gasoline were carried out, these substances haven't functional groups as the ammonia, so they were less adsorbed, and it was confirmed a chemical adsorption preferably. The activation temperature, the relationship of impregnation (RI and the concentration of the acid dissolution haven't a significant influence in the capacity of

  16. Carbones nanoporosos para la captura/almacenamiento de CO2 y CH4

    OpenAIRE

    Casco, Mirian Elizabeth

    2015-01-01

    En esta memoria de Tesis Doctoral queda demostrado que los residuos de petróleo son excelentes candidatos para el diseño y preparación de carbones nanoporosos de elevada área superficial y volumen de poros para ser utilizados en múltiples aplicaciones. No solo se han podido diseñar carbones capaces de capturar grandes cantidades de CO2, sino que también se han preparado carbones activados que demostraron resistencia mecánica al ser compactados y así ser capaces de almacenar grandes cantidade...

  17. DETERMINACIÓN DE LA ENTALPÍA DE INMERSIÓN DE CARBÓN ACTIVADO EN SOLUCIONES ACUOSAS DE FENOL Y SU RELACIÓN CON LA CAPACIDAD DE ADSORCIÓN

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2008-02-01

    Full Text Available Se determinan las entalpías de inmersión a 298 K de un carbón activado comercial microporoso en soluciones acuosas defenol en un rango de concentración de 10 a 100 mg L-1, sin control de pH; se obtienen valores entre 15 y 36 J.g-1.Se determina la cantidad de fenol adsorbido en el carbón activado en el mismo rango de concentraciones y se calcula la cantidad adsorbida en la monocapa de 164 mg.g-1.Se establece la relación entre el calor de inmersión y la cantidad de fenol adsorbido y se aprecia un mayor cambiopara el calor de inmersión en la región intermedia del rango de concentración estudiado.

  18. Caracterización de biodiesel obtenido de aceite residual de cocina

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    Betselene Murcia Ordoñez

    2013-06-01

    Full Text Available Título corto: Biodiesel de aceite residual de cocina Título en ingles: "Characterization of Biodiesel obtained from waste cooking oil" Resumen Se realizó un análisis físico y químico a cada uno de los siguientes tipos de aceite: desechado proveniente de asaderos de pollo, usado de hogares y fresco adquirido en el mercado local de la ciudad de Florencia, Caquetá (Colombia. Se evaluaron los siguientes parámetros: Peso específico, índice de yodo, índice de saponificación, índice de refracción, humedad y materia volátil, punto de fusión, impurezas insolubles, índice de acidez, coeficiente específico de extinción valores K232 y K270, color y prueba de Kreiss. Igualmente se evaluaron los espectros UV-VIS de los tres tipos de aceite estudiados. Se ensayaron siete diferentes tipos de catalizadores para la reacción de transesterificación manteniendo en todos los casos la proporción de catalizador: aceite 38:190 (v/v, tiempo de reacción (2h y temperatura de reacción (60°C. Se lograron rendimientos de biodiesel de 75.8% de aceite desechado usando KOH 1,269%p/v/MeOH 99%; 87.50% de aceite usado con KOH 0,537%p/v/MeOH 99% y 86.60% de aceite fresco usando KOH 0,457%p/v/MeOH 99%. Al biodiesel obtenido en cada caso se le determinó peso específico, índice de refracción, humedad y materia volátil, cenizas sulfatadas, carbón residual, corrosión a la lámina de cobre y perfil de ácidos grasos. En todos los casos hubo predominio de ácido  palmítico, ácido  oléico y ácido  esteárico en los aceites usados y desechados. Del análisis por cromatografía de gases acoplada a espectrometría de masas se pudo establecer que el contenido total de ésteres metílicos de ácidos  grasos es del 98,38% para el biodiesel de aceite desechado; 99,53% para el biodiesel de aceite usado y 97, 69% para el biodiesel de aceite fresco. Palabras clave: aceite residual de cocina; biodiesel; ácidos grasos; transesterificación Abstract Aphysical and

  19. GEL OBTENIDO TRIBOQUÍMICAMENTE Y ELUCIDACIÓN DE SUS COMPONENTES

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    Lilia Fernández

    2012-01-01

    Full Text Available El presente trabajo tiene como objetivo reportar un gel obtenido triboquimicamente en la reacción de Cannizzaro y la elucidación de sus componentes. La reacción entre benzaldehido e hidróxido de sodio llevada a cabo sin disolvente y agitando las fases (método triboquímico forma una suspensión que reacciona rápidamente (1 minuto, produciendo un gel blanco, el análisis infrarrojo arroja alcohol bencílico y benzoato de sodio. La difracción de rayos X confirma la fase continua del gel como benzoato de so dio. El análisis micrográfico del gel muestra una fase amorfa correspondiente al benzoato de sodio. La exposición del gel triboquímico a un rayo láser permite observar la dispersión de la luz. La técnica triboquímica es un proceso limpio acorde con los principios de la química verde. La espectroscopía en fa se sólida y de los líquidos sin disolventes contribuye al desarrollo de una química analítica verde.

  20. Descripción matemática y simulación de sistemas de lodos activados para el tratamiento de aguas residuales

    Directory of Open Access Journals (Sweden)

    Agustín Benítez Hernández

    2010-10-01

    Full Text Available Se realiza la descripción matemática de la planta depuradora que brinda servicio a las instalaciones hoteleras del Complejo Turístico Sol-Meliá en Varadero. Basado en el esquema de tratamiento mediante lodos activados que opera en esta cadena hotelera, se desarrollan los modelos matemáticos que caracterizan a este proceso de depuración en estado estacionario, permitiendo simular mediante ordenadores el funcionamiento de esta instalación o de otras similares.Para la descripción se realizan los modelos fenomenológicos con un nivel de descripción macroscópico para representar los balances de materiales, las ecuaciones cinéticas que describen las reacciones ocurridas en los bioprocesos y las ecuaciones de diseño que detallan las particularidades de los equipos.Se desarrollan los modelos del reactor, sedimentador y otros módulos elementales como divisores, mezcladores, etc. comprobándose la calidad de ajuste de los mismos.

  1. EL RECEPTOR IONOTRÓPICO DE GLUTAMATO ACTIVADO POR N-METIL-D-ASPARTATO, MOLÉCULA CLAVE DE LA CONCIENCIA

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    L. Lareo

    2006-06-01

    Full Text Available Este trabajo presenta la propuesta de que una molécula, de relativo reciente conocimiento: el receptor ionotrópico de glutamato activado por N-metil-D-aspartato (iGluR-NMDA, es la molécula clave de la conciencia. Esta propuesta que se enmarcaría en lo que se puede llamar un Correlato Molecular de la Conciencia (CMC va más allá de las propuestas hechas por el premio Nóbel Francis Crick y Christof Koch cuando iniciaron esta ruta de investigación con lo que denominaron el Correlato Neuronal de la Conciencia (CNC y de la propuesta de Hans Flohr, centrada también en el iGluR-NMDA, pero fundamentada sólo en el papel que éste tiene en los procesos de anestesia. El CMC se justifica en aspectos no considerados hasta ahora como su expresión en corteza cerebral, las modificaciones moleculares subyacentes a los denominados estados alterados de la conciencia (EAC y las diferencias de composición evidenciadas entre animales y el hombre.

  2. Reducción de pentaclorofenol en el agua cruda del río cauca mediante adsorción con carbón activado en procesos de potabilización

    OpenAIRE

    Cruz Vélez, Camilo Hernán; González, Magally; Gutiérrez, Héctor Mario; Barba, Luz Edith; Escobar, Juan Carlos; Germán Delgado, Luis; Torres, Patricia

    2010-01-01

    La reducción del riesgo químico del agua cruda del río Cauca causado por la presencia de pentaclorofenol y materia orgánica (color real, absorbancia UV254) se evaluó a escala de laboratorio mediante tres secuencias de tratamiento: adsorción con carbón activado en polvo (CAP); adsorción–coagulación y adsorción–desinfección-coagulación. Los resultados mostraron que el CAP es un compuesto adecuado para la remoción del pentaclorofenol y que su uso conjunto con el coagulante (sulfato de aluminio) ...

  3. INFLUENCIA DEL pH SOBRE LA ADSORCIÓN EN CARBÓN ACTIVADO DE Cd(II Y Ni(II DESDE SOLUCIONES ACUOSAS

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    Paola Rodríguez

    2011-01-01

    Full Text Available La adsorción de iones Cd(II y Ni(II desde soluciones acuosas sobre carbón activado se estudia con diferentes valores de pH. La adsorción de los iones se realiza en dos condiciones de pH de la solución: en la primera el pH varía en el transcurso del proceso a medida que los iones se adsorben y en la segunda el pH se mantiene fijo durante la adsorción. Cuando no se realiza un control en el pH de la solución se observan incrementos en la concentración de los iones hidronio que alcanzan un valor máximo alrededor de pH 4, para los dos iones, y cuyos valores son de 346 mmol mL-1 para el caso de la adsorción de Cd(II y de 436 mmol mL-1 para el Ni(II. Para todos los valores de pH y las dos condiciones del proceso de adsorción se observa una mayor cantidad de Ni(II adsorbida con valores entre 0,04 y 0,42 mmol.g-1, mientras que para el Cd(II la máxima cantidad adsorbida es de 0,16 mmol.g-1. El aumento de los iones hidronio en las soluciones de Cd(II y Ni(II, en las que no se controla el valor del pH, favorece el proceso de adsorción, en tanto que al mantener un pH fijo en la solución, se obtienen adsorciones menores de los iones.

  4. Actividad antibacteriana de soluciones acidas de quitosano obtenido de exoesqueleto de camarón

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    Alexander Pérez Cordero

    2014-06-01

    Full Text Available Título en ingles: Antibacterial activity of chitosan acid solutions obtained from shrimp exoskeleton Título: quitosano actividad antibacterianaResumen: El trabajo tuvo como objetivo evaluar la actividad antibacteriana in vitro de soluciones ácidas de quitosano obtenido a partir del exoesqueleto de camarón, sobre siete bacterias patógenas, cinco de las cuales corresponden a patógenas de humanos (Enterococcus faecalis ATCC 29212, Escherichia coli UDS, Pseudomonas aeruginosa ATCC 27853, Klebsiella oxytoca ATCC 43863 y  K.  oxytoca ATCC 43086 y las fitopatógenas (Pectobacterium sp UDS y  Burkholderia glumae 320012-CIAT. Concentraciones de soluciones de quitosano  de 1.0, 1.5, 2.0, 2.5, 3.0 y 3.5 % (v/v disuelto en  ácido acético de 1.0, 1.5, 2.0 % (v/v fueron preparadas; a partir de estas concentraciones, mediante la técnica de Kirby-Bauer se evaluó la actividad antibacteriana in vitro. Los resultados de actividad antimicrobiana mostraron diferencias altamente significativas entre la especie de bacteria y los tratamientos de quitosano. Las bacterias P. aeruginosa, E. coli, K. oxytoca (ATCC 43086 y ATCC 43863 fueron las más susceptibles a los tratamientos, mientras que E. faecalis, Pectobacterium sp y B. glumae mostraron resistencia. Los tratamientos T3, T4, T5, T7, T8, T9 en donde las concentraciones de quitosano estuvieron por encima a las del ácido acético, se presentaron mayores valores medios de actividad de antimicrobiana en mm y aumentó este valor para los tratamientos  T9 (5.8095 mm, T8 (6.00 mm para y  T9 (5.8095 mm, donde las concentraciones  de quitosano  de 2.5 y 3.5%, disuelta en ácido acético fueron igual a 2%.  Los resultados de este estudio en el Caribe Colombiano permitirán a futuro el reaprovechamiento del exoesqueleto de camarón como fuente de quitosano como un compuesto potencial frente al manejo al problema de salud pública ocasionada por las enfermedades bacterianas. Palabras claves: camar

  5. Evolución microestructural de composites SiC/aleaciones CuSi obtenidos a través de infiltración reactiva

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    Cornejo, J.

    2010-06-01

    Full Text Available The microstructural evolution of composites of SiC/Cu-Si alloys obtained through process of reactive infiltration to 1400 °C was studied. Three zones were detected in the obtained composites: the reaction zone, the transition zone and the infiltrated zone. In the reaction zone and transition zone the resulting microstructure was composed of a metallic phase, graphite laminae and SiC particles. It was found that SiC decomposes into these areas because of the alloy Cu-Si, so the available Si forms a liquid solution that a room temperature consisted of a α solid solution and a γ phase (Cu5Si. The carbon resulting from the decomposition of SiC precipitated as graphite laminae. In addition, the SiC decomposition was decreasing as the initial amount of Si in the alloy increased.

    Se estudió la evolución microestructural de composites de SiC/aleaciones Cu-Si obtenidos a través del proceso de infiltración reactiva a 1400 °C. Se detectaron tres zonas en los composites obtenidos: zona de reacción, transición e infiltrada. En la zona de reacción y de transición, la microestructura resultante estuvo compuesta por una fase metálica, láminas de grafito y partículas de SiC. Se encontró que el SiC se descompone en estas zonas por efecto de la aleación Cu-Si, por lo que el silicio disponible forma una solución líquida que a temperatura ambiente estuvo formada por una solución sólida α y una fase γ (Cu5Si. El carbono resultante de la descomposición del SiC precipitó como láminas de grafito. Además, la descomposición del SiC fue disminuyendo a medida que la cantidad de silicio en la aleación inicial se incrementó.

  6. Implicaciones farmacológicas de los receptores activados por los proliferadores de peroxisomas (PPAR Pharmacologic implications of peroxisome proliferator activated receptors (PPAR

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    Luis Carlos Mejía Rivera

    2001-01-01

    Full Text Available Los receptores activados por los proliferadores de peroxisomas (PPAR son un grupo de proteínas pertenecientes a la familia de receptores de ubicación nuclear que se comportan como factores que modulan la transcripción del DNA al unirse a elementos de respuesta específicos de ciertos genes blanco. Hasta el momento se han descrito tres tipos principales de PPAR designados como α, δ, y γ; estos receptores se encuentran involucrados en la regulación de diferentes procesos metabólicos; por esto se han convertido en uno de los grupos de receptores más intensamente estudiados. Los PPARα participan tanto en el catabolismo de los ácidos grasos como en el transporte extracelular de lípidos; los fibratos, sus agonistas, tienen utilidad ampliamente demostrada en el manejo de algunas dislipidemias. Las tiazolidindionas utilizadas como fármacos antihiperglicemiantes son agonistas de los PPARγ; todavía existen muchos interrogantes acerca de su relación con el metabolismo de los carbohidratos pero su uso en el manejo de la diabetes mellitus tipo 2 cada vez gana más importancia. Por otro lado, los antiinflamatorios no esteroideos se relacionan de alguna manera con las funciones de los PPARδ; hasta el momento se ha logrado establecer una relación molecular y epidemiológica de estos fármacos y receptores con el cáncer de colon. PPAR are a group of proteins, members of the receptors located within the nucleus. These receptors modulate DNA transcriptional activity by binding to specific response elements on target genes. To date, three main types of PPAR have been identified designed α, δand γthese receptors are involved in the regulation of diferent metabolic processes, being the group of receptors more intensely studied. PPARαare greatly involved in both catabolism of fatty acids and transport of extracellular lipids; fibrates, their agonists, are of proved usefulness in some dyslipidemias. Thiazolidinediones used as antihyperglicemiant

  7. Calibration of the hydraulic model of a full-scale activated sludge plant; Calibracion hidraulica a escala real de un reactor de lodos activados

    Energy Technology Data Exchange (ETDEWEB)

    Fall, Cheikh [Universidad Autonoma del Estado de Mexico (Mexico); Loaiza-Navia, Jimmy [Servicios de Agua y Drenaje de Monterrey (Mexico)

    2008-04-15

    When planning to simulate a wastewater treatment plant (WWTP) with the activated sludge model number 1 (ASM1), one of the first requirements is to determine the hydraulic model of the reactor. The aim of this study was to evaluate the hydrodynamic regime of the aeration tank of a municipal WWTP by using a rhodamine tracer test and the Aquasim simulation software. A pre-simulation was performed in order to quantify the appropriate colorant mass, set up a sampling plan and evaluate the anticipated visual impact of the tracer test in the river receiving the treated effluents. A tracer test and dynamic flow measurements were carried out, the results of which served to establish and calibrate the hydraulic model. The evaluated tank was physically built as a plug-flow reactor subdivided in 7 compartments, but the study revealed that it is best represented by a model with 5 virtual mixed reactors in series. Through the study, the approach of using a WWTP simulator for hydraulics calibration was shown to be a powerful and flexible tool for designing a tracer test and for identifying adequate tank-in-series models of full-scale activated sludge aeration tanks. [Spanish] Cuando se planea simular una planta de tratamiento con base en el modelo numero 1 de lodos activados (ASM1), uno de los primeros requisitos es determinar el modelo hidraulico del reactor. En este trabajo se estudio el regimen hidrodinamico del tanque de accion de una planta de tratamiento de aguas residuales municipales (PTAR), utilizando una prueba de trazador con rodamina y un programa de simulacion (Aquasim). Se realizo una prueba de trazador con el experimento, lo que permitio determinar la cantidad requerida de trazador, fijar los intervalos de muestreo y limitar el impacto visual anticipado del colorante sobre el rio que recibe el efluente tratado. Se llevaron a cabo la prueba de trazador y la medicion de los perfiles dinamicos de caudales, cuyos resultados sirvieron para establecer y calibrar el

  8. Estudio de la resistencia a la corrosión electroquímica de electro-recubrimientos níquel/cobre obtenidos por corriente pulsante

    Directory of Open Access Journals (Sweden)

    William Aperador Chaparro

    2010-01-01

    Tafel, las cuales permitieron encontrar que la mayor velocidad de corrosión es para los recubrimientos obtenidos con la técnica de corriente directa y la de menor es para la de corriente pulsante inversa. Finalmente, se establece que las técnicas de corriente pulsante generan depósitos que incrementan la resistencia a la corrosión de los recubrimientos obtenidos.

  9. Postratamiento en escala piloto del lixiviado del relleno sanitario Antanas (Pasto-Nariño por filtración-adsorción con arena, antracita y carbón activado

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    Andrés Felipe López Guerrero

    2015-12-01

    Full Text Available Esta investigación evaluó el postratamiento del lixiviado del relleno sanitario Antanas mediante tres filtros ascendentes en serie con arena, antracita y carbón activado granular. Se evaluaron rangos de tasas de filtración de 20-35, 60-100 y 150 300 m3/m2*d correspondientes a tiempos de contacto con el carbón de 48, 24 y 8 minutos. El seguimiento a cada condición se efectuó durante un mes, las remociones medias de DQO para dichas tasas y tiempos fueron 60,2, 54,3 y 31,4% respectivamente. El mejor desempeño del sistema dependió fundamentalmente del aumento del tiempo de contacto y no de la reducción de las tasas de filtración.

  10. MODELO PARA SIMULAR LA HOMEÓSTASIS NEURONAL DURANTE UN INFLUJO INCREMENTADO DEL CALCIO A TRAVÉS DEL CANAL ASOCIADO AL RECEPTOR IONOTRÓPICO DE GLUTAMATO ACTIVADO POR N-METIL-D-ASPARTATO

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    L. Lareo

    2005-12-01

    Full Text Available Dada la importancia del receptor ionotrópico de glutamato activado por N-Metil-D-Aspartato en los procesos de aprendizaje y la formación de la memoria mediados por el transporte de calcio a través del canal asociado a dicho receptor resulta importante desarrollar modelos que permitan comprender la homeóstasis que le permite a la neurona manejar incrementos en el flujo de dicho catión sin llegar a desarrollar procesos necróticos ni apoptóticos. Este trabajo presenta una sencilla simulación de parte de los procesos metabólicos asociados al receptor como un paso inicial para comprender los mecanismos subyacentes al aprendizaje y memoria.

  11. Aplicação de compósitos de TiO2 em carvão activado na fotodegradação do fenol com luz ultravioleta

    OpenAIRE

    Fernandes, Isabel Margarida Duarte

    2009-01-01

    Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Engenharia Química e Bioquímica O presente trabalho tem como objectivo principal o estudo da viabilidade da aplicação de compósitos de dióxido de titânio (TiO2) impregnados em carvão activado (CA) na fotodegradação do fenol, no âmbito do tratamento de águas residuais. A base deste estudo é o uso de processos oxidativos avançados (POA), como a fotocatálise heterogé...

  12. Eliminación del dodecilbencensulfonato sódico de las aguas mediante adsorcion en carbones activados, ozonización catalizada y fotoxidación

    Directory of Open Access Journals (Sweden)

    J.D. Méndez-Díaz

    2008-12-01

    Full Text Available Se estudian las posibilidades que presentan algunos de los tratamientos de aguas más importantes en la eliminación del dodecilbencensulfonato sódico (SDBS. La influencia de las diferentes variables operacionales, así como el mecanismo implicado en cada proceso también han sido objeto de estudio.

  13. RELACION ENTRE LA ENTALPÍA DE INMERSIÓN DE UN CARBÓN ACTIVADO EN SOLUCIONES ACUOSAS DE Pb2+ Y LOS PARAMETROS DE ADSORCIÓN

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    Liliana Giraldo

    2008-03-01

    Full Text Available Se prepara un carbón activado a partir de carbón mineral por impregnación con solución al 50% de ácido fosfórico, el cual presenta un área superficial de 586 m2.g-1 y un volumen total de poro de 0,37 cm3g-1; en lo que respecta a características químicas el carbón activado presenta un mayor contenido de sitios ácidos, 0,92 meq g-1, que de sitios básicos, 0,63 meq g-1 , que le proporcionan una característica aproximadamente neutra con un pHPZC de 7,4.La cantidad adsorbida de Pb2+ y la entalpía de inmersión en soluciones de a diferentes valores de pH,  muestran que estos valores son máximos para pH 4 con valores de 15,7 mgg-1 y 27,6 Jg-1 respectivamente. Se establecen comportamientos semejantes de la entalpía de inmersión y la cantidad adsorbida en función del pH; y se obtienen relaciones del tipo función de segundo grado entre la constante de adsorción y la entalpía de inmersión y entre dicha constante y el pH de la solución.

  14. Efecto del carbón activado, ácido indolacético (AIA y bencil amino purina (BAP en el desarrollo de protocormos de Epidendrum elongatum Jacq bajo condiciones in vitro

    Directory of Open Access Journals (Sweden)

    Jaime Alonso Pedroza-Manrique

    2009-06-01

    Full Text Available The effect of activated charcoal, indol acetic acid (IAA and benzylaminopurine (BAP on Epidendrum elongatum Jacq protocorm-like body (PLB development in vitro conditions Resumen:  El desarrollo vegetativo de los protocormos de Epidendrum elongatum Jacq., una orquídea endémica y en vías de extinción, se logró eficazmente mediante el cultivo in vitro en el medio Murashige y Skoog (1962, donde se evaluó el efecto de la interacción entre los siguientes tres factores: carbón activado (0,0; 0,5; 1,0% (w/v; ácido indol acético (0,0; 0,5; 1,0 mg.L-1; bencil amino purina (0,0; 0,5; 1,0 mg.L-1. El medio de cultivo empleado fue enriquecido con sacarosa al 3%, y el Myo inositol al 0,1 g.L-1. En este estudio se evaluó que el efecto sobre la tasa de crecimiento de la interacción del carbón activado en concentraciones de 0,5 y 1,0% con 0,5 mg.L-1 de AIA es positivo para el desarrollo de los protocormos de E. elongatum bajo condiciones in vitro, mientras que la interacción del BAP, tanto en concentraciones de 0,5 mg.L-1 y 1,0 mg.L-1, muestra resultados no tan favorables en cuanto al grado de desarrollo de los protocormos estudiados. Este estudio describe un protocolo que permite alcanzar más de 270.000 plántulas en excelente desarrollo vegetativo dentro de 30 semanas, a partir de una cápsula de esta importante orquídea. Este protocolo es un modelo de conservación para especies que se encuentran en vías de extinción, y además permite la propagación a gran escala de Epidendrum elongatum. Palabras clave: orquídea, Epidendrum elongatum, germinación in vitro, carbón activado, AIA, BAP. Abstract: The vegetative development of protocorm-like bodies (PLB from Epidendrum elongatum Jacq. (an endemic and endangered orchid was effectively achieved through in vitro culture in Murashige and Skoog medium (1962; the effect of the interaction between the following three factors was studied: activated charcoal (0.0, 0.5, 1.0% (w/v, indol acetic acid

  15. COMPORTAMIENTO DIELÉCTRICO DE HIDROGELES DE ALCOHOL POLIVINÍLICO OBTENIDOS POR LA TÉCNICA CONGELAMIENTO/DESCONGELAMIENTO

    Directory of Open Access Journals (Sweden)

    MARTA ELENA LONDOÑO

    2011-01-01

    Full Text Available Los hidrogeles de alcohol polivinílico, PVA, presentan propiedades de gran interés para ser usadas en la industria electrónica, la microelectrónica, la optoelectrónica y la medicina. El estudio de sus propiedades dieléctricas permiten conocer su comportamiento, especialmente, como aislante y definir así sus aplicaciones específicas en las áreas anteriormente mencionadas. En este estudio se presenta el comportamiento dieléctrico de hidrogeles de alcohol polivinílico obtenidos por la técnica de congelamiento/descongelamiento, para ello se hizo uso de la espectroscopía de relajación dieléctrica, DRS. Los resultados muestran los diferentes fenómenos a que da origen el agua presente en los hidrogeles. Así, las propiedades dieléctricas de los hidrogeles de PVA son totalmente dependientes del porcentaje de agua que quede atrapada en su estructura.

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

    Directory of Open Access Journals (Sweden)

    Conde, A.

    2005-12-01

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

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

  17. Factores que afectan a la estructura de los recubrimientos de cinc obtenidos por inmersión

    Directory of Open Access Journals (Sweden)

    Seré, P. R.

    1997-12-01

    Full Text Available Coating solidification during hot-dip galvanizing is a very complex process due to Al-Fe, Al-Fe-Zn and Fe-Zn intermetallic compounds development. Fe-Zn intermetallic are brittle and detrimental for the coating ductility, while the diffusion towards the surface of a segregated insoluble alloying such as antimonium causes the sheet darkness. Steel sheets of different roughness were hot-dip galvanized under different operation conditions using a laboratory scale simulator. The effect of steel roughness and process parameters upon coating characteristics were analyzed. Experimental results showed that the steel roughness affects the coating thickness, zinc grain size and texture as well as the out-bursts development, while the process parameters affects the Fe2Al5 morphology and antimonium segregation.

    En el proceso de galvanizado por inmersión, la solidificación del recubrimiento constituye una etapa compleja en la que, además de formarse compuestos intermetálicos de Al-Fe, Al-Fe-Zn y Fe-Zn, tiene lugar la segregación de elementos aleantes insolubles como el antimonio. Ambos fenómenos son, al menos parcialmente, indeseables ya que la fragilidad de los intermetálicos de Fe-Zn afecta a la ductilidad del recubrimiento y la difusión del antimonio hacia la superficie causa su ennegrecimiento. Con un simulador diseñado a escala de laboratorio se galvanizaron chapas de diferente rugosidad sujetas a condiciones operativas también diferentes, analizándose el efecto de la rugosidad del acero y de los parámetros del proceso sobre las características del recubrimiento. Los resultados obtenidos demostraron que la rugosidad afecta tanto al espesor del recubrimiento, tamaño de grano y textura del cinc como a la formación de out-bursts, mientras que los parámetros del proceso lo hacen sobre la morfología del intermetálico Fe2Al5 y la segregación de antimonio.

  18. Observaciones microestructurales en el composite Al-SiC-15p obtenido por el procedimiento de compocolado

    Directory of Open Access Journals (Sweden)

    Manzano-Ramírez, A.

    1996-12-01

    composite y de ello poder inferir, al menos cualitativamente, el grado de integración de las partículas de refuerzo en la matriz. Además, se emplearon las posibilidades de análisis del microscopio electrónico de barrido (SEM para tratar de determinar la composición de la fase responsable de la adherencia matriz-partícula de refuerzo. Los resultados obtenidos en el AFM confirmaron que el atrapamiento de las partículas de refuerzo, cuando estas tienen morfología esferoidal, es más eficiente a altas fracciones de sólido (fs > 0,4 y elevadas velocidades de corte (γ > 120 s-1, mientras que a bajas fracciones de sólido (fs < 0,3 y bajas velocidades de corte (γ < 27 s-1 el atrapamiento es menos efectivo. Por otro lado, se presenta una evidencia cualitativa que ilustra el mecanismo de fragmentación dendrítica, consecuencia de la evolución de la estructura del sólido primario de dendrítica a globular. Finalmente, los resultados obtenidos con el SEM sugieren que la adherencia podría establecerse a través de la fase rica en silicio; sin embargo, debido al tamaño del haz de electrones, se considera que esta técnica de análisis no es la más adecuada.

  19. Nuevo enfoque para el pronóstico de la concentración de sólidos en lodos obtenidos por sedimentación gravitacional

    Directory of Open Access Journals (Sweden)

    Roger S. Almenares-Reyes

    2007-03-01

    Full Text Available Se emiten recomendaciones para el desarrollo de las investigaciones orientadas al perfeccionamiento del pronóstico de la concentración de sólidos en lodos obtenidos por sedimentación gravitacional. Mediante los métodos histórico, lógico y el de la experimentación pasiva, se estudia el pronóstico de la concentración de sólidos en lodos obtenidos por sedimentación gravitacional en la práctica industrial, en la planta de espesadores de la empresa PSA-Moa Nickel S.A. Se concluye que para dar solución al pronóstico de la concentración de sólidos en lodos obtenidos por sedimentación gravitacional, es recomendable dirigir la investigación al estudio teórico y empírico de la correlación estadística entre esta variable y la concentración de sólidos obtenida por otros métodos de separación mecánica.

  20. OXIDACIÓN DE LA SUPERFICIE DE CARBÓN ACTIVADO MEDIANTEHNO3 Y H2O2: EFECTO SOBRE LA REMOCIÓN DE NÍQUEL (IIEN SOLUCIÓN ACUOSA

    Directory of Open Access Journals (Sweden)

    Paola Rodriguez estupiñan

    2011-11-01

    Full Text Available Este trabajo analiza el efecto de la modificaciónde la química superficial deun carbón activado granular, CAG, poroxidación con ácido nítrico, CAG-N,y peróxido de hidrogeno, CAG-P en laadsorción de iones níquel desde soluciónacuosa.Las muestras obtenidas se caracterizarona través de diferentes técnicas; laquímica superficial se evaluó por determinacionesde acidez y basicidad total,punto de carga cero y espectroscopia IR,que muestran el efecto del agente oxidante.Los parámetros texturales, como áreasuperficial BET y volúmenes de poro, seevaluaron mediante adsorción de gases.Los valores de área superficial BET delos sólidos se encuentran entre 816 y 876m2g-1, adicionalmente se determinaronentalpías de inmersión de los carbonesactivados en agua y benceno.Finalmente, los resultados experimentalesde la adsorción desde soluciónse ajustaron a los modelos de Langmuir,Freundlich, Redlich-Peterson y Toth,y se encontró el mejor ajuste para esteúltimo. Los valores de la capacidad deadsorción determinadas por el modelo deLangmuir están entre 29,68 y 50,97 mgg-1, lo que indica que la capacidad de adsorcióndepende, en gran medida, de laquímica superficial del sólido.

  1. Activated receptors for peroxisomic proliferators. Its role in the atherosclerosis, obesity and high blood pressure. Los receptores activados por proliferadores peroxisómicos. Su papel en la aterosclerosis, obesidad e hipertensión arterial.

    Directory of Open Access Journals (Sweden)

    Yosvel Curbelo Pérez

    2004-08-01

    Full Text Available The receptors activated by peroxisome proliferators are a family of factors of transcription that belong to the superfamily of the steroid receptors and include tree subtypes which are PPARá, PPAR©¬ and PPAR ã. These receptors join to direct hexameric repetitions in the form of heterodimers with the retinoid receptor. PPAR receptors regulate the expressions of a great variety of genes that codify the proteins that are implied in the lipid metabolism, the energetic homeostasis, the cellular differentiation and the formation of tumours. This review describes the features, regulation and target genes of the PPAR receptor and the physiopathological and pharmacological implications of the regulation of the lipid and glucose metabolism, the energetic homeostasis ,hypertension and endothelial dysfunction.

    Los receptores activados por proliferadores peroxisómicos son una familia de factores de transcripción que pertenecen a la superfamilia de los receptores esteroides y que incluye tres subtipos: PPARá, PPAR©¬ y PPAR ã. Estos receptores se unen a repeticiones directas hexaméricas en forma de heterodímeros con el receptor del retinoide. Los PPAR regulan la expresión de una amplia variedad de genes que codifican proteínas implicadas en el metabolismo lipídico, la homeostasis energética, la diferenciación celular y la formación de tumores. En esta revisión se describen las características, regulación y los genes diana de los PPAR y se destacan sus implicaciones fisiopatológicas y farmacológicas sobre la regulación del metabolismo de los lípidos y la glucosa, la homeostasis energética, la hipertensión arterial y la disfunción endotelial.

  2. Tratamiento de agua residual doméstica sin clarificación primaria en un sistema de lodos activados en la modalidad de estabilización por contacto

    Directory of Open Access Journals (Sweden)

    Tatiana Mañunga

    2012-01-01

    Full Text Available El sistema de lodos activados en la modalidad de estabilización por contacto (SLAEC es una tecnología de tipo biológico ampliamente utilizada para el tratamiento del agua residual, la cual generalmente es precedida por una clarificación primaria (CP. En este trabajo se evaluó el efecto de la eliminación de la CP sobre el desempeño de un SLAEC a escala piloto, para el tratamiento de agua residual doméstica, analizando el comportamiento de los sólidos suspendidos volátiles en el licor mixto (SSVLM, la concentración de DQO, DBO5 y SST. Adicionalmente, el sistema fue operado con CP para comparar su desempeño con el observado cuando se eliminó la CP. Los resultados indicaron que la eliminación de la CP incrementó en un 44% la concentración de materia orgánica biodegradable afluente al sistema, y aumentó la vulnerabilidad del SLAEC sobre los efectos desfavorables que generan la presencia de grasas, aceites (G/A y surfactantes en el agua residual, los cuales se tradujeron en la formación de una capa de lodo flotante en el sedimentador secundario, que afectó el desempeño de esta unidad y la calidad del lodo. No obstante, en las dos configuraciones evaluadas, el SLAEC alcanzó eficiencias de reducción de DQO, DBO5 y SST superiores al 76%.

  3. Caracterización de propóleos provenientes del municipio de Caldas obtenido por dos métodos de recolección

    Directory of Open Access Journals (Sweden)

    Julián Martínez G.

    2012-04-01

    Full Text Available Objetivo. Determinar las características fisicoquímicas y la actividad antimicrobiana de propóleos de Apis mellifera, provenientes del municipio de Caldas, obtenidos por dos métodos de recolección. Materiales y métodos. Se utilizaron dos métodos de recolección: de raspado y trampa plastica. Se estableció el contenido de cera, ceniza, material insoluble y resina de los propóleos crudos. Al extracto etanólico de los propóleos se les determinó el perfil cromatográfico (GC-MS y el espectro UV; además, se evaluó la actividad antimicrobiana in vitro frente a hongos (Aspergillus sp., Penicillium sp., Colletotrichum acutatum y C. gloesporioides, y bacterias (Salmonella tiphy, Bacillus subtilis, Staphylococcus aureus y Escherichia coli. Resultados. El material obtenido mediante malla matrizada presentó un perfil químico amplio, buena actividad antimicrobiana y mejores parámetros de calidad, de acuerdo con estándares establecidos por normas internacionales que los propóleos obtenidos por el método de raspado. Además, pudo observarse que la acción antimicrobiana de los propóleos fue dependiente de la concentración del extracto y del hongo o bacteria evaluada. Conclusiones. La composición química y la actividad antibacteriana y antifúngica de los propóleos están relacionadas con el método de recolección. El presente estudio aporta información para la selección de la técnica de cosecha del propóleo de acuerdo con la aplicación que se desee dar.

  4. Evaluación de los errores de modelos digitales de elevación obtenidos por cuatro métodos de interpolación

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    Azucena Pérez Vega

    2009-01-01

    Full Text Available Son pocos los estudios enfocados en la evaluación de los errores inherentes a los modelos digitales de elevación (MDE. Por esta razón se evaluaron los errores de los MDE obtenidos por diferentes metodos de interpolación (ARC/INFO, IDRISI, ILWIS y NEW-MIEL y con diferentes resoluciones, con la finalidad de obtener una representación del relieve más precisa. Esta evaluación de los métodos de interpolación es crucial, si se tiene en cuenta que los MDE son la forma más efectiva de representación de la superficie terrestre para el análisis del terreno y que son ampliamente utilizados en ciencias ambientales. Los resultados obtenidos muestran que la resolución, el método de interpolación y los insumos (curvas de nivel solas o con datos de escurrimientos y puntos acotados influyen de manera importante en la magnitud de la cantidad de los errores generados en el MDE. En este estudio, que se llevó a cabo con base en curvas de nivel cada 50 m en una zona montañosa, la resolución más idónea fue de 30 m. El MDE con el menor error (Error Medio Cuadrático -EMC- de 7.3 m fue obtenido con ARC/INFO. Sin embargo, programas sin costo como NEWMIEL o ILWIS permitieron la obtención de resultados con un EMC de 10 m.

  5. COMPORTAMIENTO DE NUEVOS GENOTIPOS DE ARROZ (Oryza sativa L. OBTENIDOS MEDIANTE CULTIVO DE ANTERAS PARA CONDICIONES DE BAJO SUMINISTRO DE AGUA

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    Elizabeth Cristo

    2006-01-01

    Full Text Available En la Estación Experimental del Arroz ¿Los Palacios¿, perteneciente al Instituto Nacional de Ciencias Agrícolas, durante los períodos poco lluvioso (frío del 2002 y lluvioso (primavera del 2003, se estudió el comportamiento de genotipos de arroz obtenidos mediante el cultivo de anteras, así como un grupo de mutantes y somaclones en condiciones de bajo suministro de agua: los genotipos 8734 y 8735 (obtenidos a través del cultivo de anteras, 8551, 8552, 8553, IAC-27 (mutaciones, 8733, INCA LP-9 (cultivo somático y como testigo de producción la variedad comercial Perla de Cuba. Para provocar las condiciones de bajo suministro de agua, se empleó el siguiente manejo: se estableció la lámina de agua a los 15 días de germinado el arroz, suspendiendo la entrada de agua a los 35 días después de germinado (DDG, reponiéndosela nuevamente en el cambio de primordio hasta después del 50 % de floración. Al momento de la cosecha se evaluaron la altura final, el ciclo del cultivo, rendimientos agrícola (t.ha-1 e industrial (% de granos enteros, así como la resistencia al acame, desgrane, Piriculariosis, manchado del grano, Sarocladium oryzae y al borer. Se encontró que el genotipo 8735 obtenido a partir del cultivo de anteras mostró excelente comportamiento en cuanto a los rendimientos agrícola e industrial, así como a las principales enfermedades que afectan económicamente a este cultivo, como es el caso del manchado del grano.

  6. Comportamiento dieléctrico de hidrogeles de alcohol polivinílico obtenidos por la técnica congelamiento/descongelamiento

    OpenAIRE

    MARTA ELENA LONDOÑO; JUAN MANUEL JARAMILLO

    2011-01-01

    Los hidrogeles de alcohol polivinílico, PVA, presentan propiedades de gran interés para ser usadas en la industria electrónica, la microelectrónica, la optoelectrónica y la medicina. El estudio de sus propiedades dieléctricas permiten conocer su comportamiento, especialmente, como aislante y definir así sus aplicaciones específicas en las áreas anteriormente mencionadas. En este estudio se presenta el comportamiento dieléctrico de hidrogeles de alcohol polivinílico obtenidos por la técnica de...

  7. Propuesta de procedimientos para mejorar los resultados obtenidos por la heurística NEH en el problema flow shop con bloqueos

    OpenAIRE

    Companys Pascual, Ramón; Ribas Vila, Immaculada; Mateo Doll, Manuel

    2010-01-01

    En este trabajo se han analizado formas de incrementar la calidad de las soluciones obtenidas por la heurística NEH al aplicarla al problema de programación de piezas en un sistema flow shop con bloqueos con el objetivo de minimizar el makespan. Los resultados obtenidos al analizar diferentes métodos indican que es aconsejable aplicar el procedimiento sobre el ejemplar directo e inverso reteniendo la mejor de las dos soluciones obtenidas así como substituir la regla de ordenación LPT por la M...

  8. Incertidumbre en caudales instantáneos obtenidos con curvas nivel–caudal construidas con una baja densidad de aforos líquidos

    OpenAIRE

    Martínez Plata, Juan Felipe; Domínguez Calle, Efraín Antonio; Rivera, Hebert Gonzalo

    2012-01-01

    En el presente trabajo se realizó un análisis de incertidumbre del proceso de construcción de la curva nivel-caudal, con el fin de estimar el error o incertidumbre de los caudales obtenidos considerando diversos escenarios de disponibilidad de aforos. Se implementó una metodología para generar muestras artificiales de aforos a partir de datos reales observados en campo y estudiar el efecto de la cantidad y distribución de las mediciones sobre la incertidumbre de los caudales instantáneos. Los...

  9. Caracterización de aislamientos de usarium spp. obtenidos de zonas productoras de uchuva (Physalis peruviana) en Cundinamarca y Boyacá

    OpenAIRE

    Rodríguez Velásquez, Edwin Alirio

    2013-01-01

    La marchitez vascular causada por Fusarium sp.es la enfermedad más importante para el cultivo de uchuva, sin embargo la información sobre aspectos taxónomicos y patógenicos es reducida. 25 aislamientos de Fusarium sp fueron obtenidos de tejido sintomático de uchuva (Physalis peruviana) en los departamentos de Cundinamarca y Boyacá, estos aislamientos se identificaron basándose en rasgos morfológicos y análisis de secuencia de los genes Factor de elongación 1α (EF1), Citocromo Oxidasa 1 (CO1),...

  10. Evaluación in vivo del efecto cicatrizante de un gel a base de quitosano obtenido de exoesqueleto de camarón blanco litopenaeus vannamei

    OpenAIRE

    Heimy Franceline Martínez Sánchez; Amada Yerén Escobedo Lozano; Evaristo Méndez-Gómez; Alfredo Emmanuel Vázquez; Manuel de Jesús Sol Hernández; Anahí Elizabeth Osuna Lizárraga

    2014-01-01

    Healing effect of a chitosan-based gel obtained from the exoskeleton of white shrimp Litopenaeus vannamei and its evaluation in vivoTítulo corto: Evaluación del quitosano como cicatrizanteResumen:  En México alrededor del 62 % de la población sufre de accidentes causantes de alteraciones en la piel como quemaduras, heridas y diabetes principalmente. Para atender esta problemática, se propone el uso de un gel de quitosano, obtenido del exoesqueleto de camarón ya que presenta actividad antimicr...

  11. Comparación entre los diagramas TTS obtenidos mediante los ensayos normalizados Huey y Strauss modificado para el acero inoxidable AISI 304

    Directory of Open Access Journals (Sweden)

    Otero, E.

    1996-04-01

    Full Text Available This work presents a comparison of Temperature-Time-Sensitization TTS diagrams obtained by Huey and modified Strauss standard, for detecting susceptibility to intergranular attack. The difference between these tests is the use of a strong or a slightly smooth oxidizing electrolyte. The diagrams obtained are different and if a sample tested by modified Strauss is sensitized, then it will be sensitized in the Huey test, but the contrary is not always true. This difference is because a sensitized sample has to have a continuous band lacking in chromium along the grain boundary in order to be sensitized in the modified Strauss test. This condition is not necessary in the Huey test.

    Se comparan los diagramas Temperatura-Tiempo-Sensibilización TTS, obtenidos mediante los ensayos normalizados de corrosión intergranular Huey y Strauss modificado, que, respectivamente, utilizan electrólitos fuerte y suavemente oxidantes, mostrándose que los diagramas obtenidos son diferentes. Si una muestra evaluada mediante el ensayo Strauss modificado se encuentra sensibilizada, entonces lo estará también en el ensayo Huey, pero no necesariamente ocurrirá lo contrario; esta diferencia se asocia a la necesidad de la existencia de una zona continua empobrecida en cromo a lo largo del límite de grano para que el material se sensibilice con respecto al ensayo Strauss modificado, condición innecesaria para el caso del ensayo Huey.

  12. Caracterización de los aceros sinterizados obtenidos a partir de polvos prealeados Fe-1,5% Mo

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    Torralba, J. M.

    1995-02-01

    Full Text Available Sintered molybdenum-, copper-, nickel- alloyed steels, have been studied through the influence of the Chemical composition on different mechanical and physical properties. In all the studied steels, a constant percentage of carbon has been used, as well Fe-Mo prealloyed powders, with a 1,5% Mo content. Selected sintering conditions were close to those used in the P/M industry, potential consumer of the studied steels.

    Se estudian los aceros aleados sinterizados con molibdeno, cobre, níquel y grafito, a partir de la influencia de su composición sobre distintas propiedades mecánicas y físicas. En todos los aceros, se utilizó una composición de carbono constante, así como polvos prealeados de Fe-Mo, con 1,5% Mo. Las condiciones de sinterización elegidas han sido las más próximas a las utilizadas en la industria pulvimetalúrgica, que es el usuario potencial de los materiales estudiados.

  13. Peroxisome proliferator-activated receptor: effects on nutritional homeostasis, obesity and diabetes mellitus Receptores activados por los proliferadores de peroxisomas: implicaciones sobre la homeostasis nutricional, en la obesidad y en la diabetes mellitus

    Directory of Open Access Journals (Sweden)

    M. Viana Abranches

    2011-04-01

    Full Text Available The obesity and the metabolic disorders associated characterize the metabolic syndrome, which has increased at an alarming rate around the world. It is known that environmental and genetic factors are involved in the genesis of obesity. Peroxisome Proliferator-Activated Receptors (PPARs stand out among these factors. They compose the nuclear receptor superfamily and there are in three isoforms (PPARα,PPARβ/δ and PPARγ, which play an important role in the regulation of the metabolism of carbohydrates, lipids and proteins. The present review aims to understand the relationship between the diet, the PPARs and the control of the blood glucose and body weight, since the understanding about the mechanisms by which these receptors act may benefit the development of the strategies aiming at prevention and elaboration of therapeutics actions which are more effective for the treatment of obesity and diabetes.La obesidad y los trastornos metabólicos asociados, que caracterizan el cuadro del síndrome metabólico, han aumentado de manera alarmante en todo el mundo. Se sabe que factores genéticos y ambientales están implicados en la génesis de la obesidad. Entre estos se destacan los Receptores Activados por los Proliferadores de Peroxisomas (PPAR, los cuales componen la superfamilia de los receptores nucleares que poseen tres isoformas de PPAR (PPARα, PPARβ/δ y PPARγ que desempeñan importante papel en la regulación del metabolismo de los hidratos de carbono, de los lípidos y de las proteínas. El presente trabajo de revisión contribuye a clarificar la interrelación existente entre la dieta, los PPAR y el control de la glucemia y peso, ya que el conocimiento de los mecanismos por los cuales estos receptores actúan, puede beneficiar el desarrollo de estrategias de prevención y elaboración de procedimientos terapéuticos más eficaces para el tratamiento de la obesidad y de la diabetes.

  14. Alternativas para la clarificación del jarabe de glucosa obtenido por hidrólisis enzimática del almidón

    OpenAIRE

    Cruz Guerrero, Gloria Teresa; González Blair, Gloria Helena; Rentería Ayala, Andira Yesil; Castellanos Domínguez, Óscar Fernando

    2010-01-01

    El presente artículo estudia algunas rutas para la separación y purificación del jarabe de glucosa obtenido por la hidrólisis enzimática del almidón de papa. El proceso de clarificación se realiza en tres etapas. La primera de ellas, la remoción de sólidos, se lleva a cabo con la aplicación de técnicas convencionales de separación de sólido-líquido como la sedimentación, centrifugación y filtración, estudiando, además el efecto de utilizar agentes floculantes y coagulantes, previo a las opera...

  15. Inoculum development by using activated sludge to remove hydrogen sulphide (H2S through biofiltration* Desarrollo de un inóculo microbiano empleando lodos activados para la remoción de ácido sulfhídrico (H2S mediante biofiltración*

    Directory of Open Access Journals (Sweden)

    Carmona Salgado Yezid

    2005-12-01

    Full Text Available Different activated sludges were used for developing an inoculum able to degrade hydrogen sulphide in a pilot scale biofiltration plant using two different support materials: sugarcane bagasse and this bagasse mixed with pumice stone. Adapting and selecting microbial species which degrade hydrogen sulphide (H2S was aided by adding nutrients plus a specific substrate to the activated sludge. Population variation was monitored within the different trophic groups in the biofiter medium during pilot scale plant operation, a general trend towards sulphur-oxidising bacteria (SOB growth being observed as was a decrease in heterotrophic bacteria, molds and yeasts. The activated sludge which showed the highest substrate degradation speed was selected for standardising inoculum preparation; the different nutritional mediums were evaluated during this process. Measuring some variables for controlling the process led to choosing the pH for determining the proper point of inoculum adaptation for this specific substrate. The inoculation procedure and support characteristics in terms of establishing and developing the microbial species increased biofilter removal efficiency by up to 99% from start-up. Key words: biofilter, activated sludge, adapted microorganisms, sulphur-oxidising bacteria, respirometry. Este artículo es el resultado de un proyecto cofinanciado por Colciencias y desarrollado por un grupo de investigadores vinculados al proyecto a través de las entidades CorporaciónSe utilizaron lodos activados de diferentes orígenes para el desarrollo de un inóculo apto para la degradación de ácido sulfhídrico en un sistema piloto de biofiltración con dos unidades de diferentes materiales de soporte: bagazo de caña en un caso y una mezcla de este y piedra pómez en el otro. Mediante la adición a los lodos activados, de medio nutritivo con un sustrato específico, se favoreció el proceso de adaptación y selección de las especies

  16. Componentes minioritarios y propiedades antioxidantes de aceites vírgenes y tortas residuales obtenidos por presión en frio a partir de fuentes vegetales convencionales y no convencionales.

    OpenAIRE

    Navas Hernández, Petra Beatríz

    2010-01-01

    Componentes minoritarios y propiedades antioxidantes de aceites vírgenes y tortas residuales obtenidos por presión en frío a partir de fuentes vegetales convencionales y no convencionales Beatriz Navas Hernández, María Desamparado Salvador Moya y Giuseppe Fregapane Resumen En el presente trabajo se evaluaron las propiedades y composición química de aceites vírgenes obtenidos por prensado en frío a nivel de planta piloto, a partir de distintas fuentes vegetales, como semillas oleagino...

  17. Actividad Antioxidante de Hidrolizados Enzimáticos de Plasma Bovino Obtenidos por Efecto de Alcalasa® 2.4 L Antioxidant Activity of Bovine Plasma Enzymatic Hydrolysates Obtained by Effect of Alcalase® 2.4 L

    OpenAIRE

    Leidy J Gómez; Omar A Figueroa; José E Zapata

    2013-01-01

    Se ha evaluado la actividad antioxidante de hidrolizados de plasma de bovino (HPB) obtenidos con Alcalasa 2.4 L a diferentes grados de hidrólisis. Los HPB se fraccionaron a través de membranas de ultrafiltración y se purificaron por cromatografía de intercambio iónico, con una posterior cromatografía líquida de alta eficiencia en fase reversa. Los resultados mostraron que los HPB obtenidos bajo las condiciones de hidrólisis planteadas, poseen una fuerte capacidad de captación de radicales áci...

  18. protegido. Resultados obtenidos en Cuba

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    María León

    2005-01-01

    Full Text Available The Irrigation and Drainage Research Institute has carried out studies related with the efficient use of the water in the cultivation of protected tomato. The works were carried out in the provinces of Havana and Havana City. The main objectives of the same ones have been guided to determine the hydric necessities of the cultivation, obtaining of necessary indicators for the watering programming and the answer of the cultivation to the hydric deficit. The results, in general indicate that under protected conditions the consumption of water or Etc decreases significantly, that is feasible the programming of the watering with the Kc obtained experimentally and the Eto estimated by Class’ A tank method and that a moderated hydric deficit in the non critical phases of the cultivation didn’t affect the production

  19. Nuevos datos experimentales sobre parámetros hidrogeológicos de la Cuenca de Madrid obtenidos a partir de muestras de sondeos

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    Villarroya Gil, F. I.

    1990-12-01

    Full Text Available A critical review of main hydrogeological parameters (porosity, permeability and specific storage coefficient of Madrid Basin Detrital Aquifer is done. For this study, data from the bibliography and new laboratory analysis of grain size distribution (26, dry density (26, specific weight (26, permeability (20 and consolidation test (6 samples from three boreholes are used. The results are quite similar to those than already exist in the literature, although the porosity obtained is higher.Se hace una revisión crítica de los principales parámetros hidrogeológicos (porosidad, permeabilidad y coeficiente de almacenamiento específico, del Terciario detrítico de la cuenca de Madrid. Para este estudio además de los datos existentes en la bibliografía, se han realizado una serie de análisis de laboratorio desarrollados en las instalaciones del SGOP obteniendo, de esta manera, nuevos valores experimentales de los citados parámetros, mediante ensayos granulométricos (26, de densidad seca (26, de peso específico (26, de permeabilidad (20 y ensayos edométricos (6. Las muestras proceden de tres sondeos realizados en el casco urbano de Madrid por el SGOP (MOPU. Los resultados obtenidos coinciden, en gran medida, con los existentes en la bibliografía, si bien, los valores de porosidad total son marcadamente más altos.

  20. Caracterización estructural de vidrios con altos contenidos de óxidos de hierro obtenidos a partir de un residuo de la hidrometalurgia del zinc

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    Romero, M.

    1997-10-01

    Full Text Available It has been carried out the structural characterization of high oxide content glasses obtained by melting of a goethite industrial waste from the zinc hydrometallurgy with other raw materials as dolomite and glass cullet. The structural characterization has been carried out by X-Ray Diffraction (XRD, X-Ray Diffraction by Amorphous Dispersion (RDF and Mossbauer spectroscopy. It has been determined the interatomic distance, the oxidation state and the coordination of iron atoms in these glasses.

    En este trabajo se ha llevado a cabo la caracterización estructural de vidrios con altos contenidos de óxidos de hierro obtenidos por fusión de un residuo industrial de goethita procedente de la hidrometalurgia del zinc con otras materias primas (dolomita y casco de vidrio. El estudio estructural se ha realizado por difracción de rayos-X (DRX, difracción de rayos-X por dispersión amorfa (RDF y espectroscopia Mössbauer, determinándose las distancias interatómicas, el estado de oxidación y la coordinación de los átomos de hierro en este nuevo tipo de vidrios.

  1. EVALUACIÓN DE LA TOLERANCIA A LA SEQUÍA EN GENOTIPOS DE TRIGO (Triticum aestivum L. OBTENIDOS EN CUBA POR INDUCCIÓN DE MUTACIONES

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    L. M. González

    2005-01-01

    Full Text Available Se estudió la tolerancia a la sequía en genotipos cubanos de trigo obtenidos por inducción de mutaciones sobre la base de la germinación y el crecimiento de las plántulas y sobre la base del rendimiento agrícola y la profundidad que exploran las raíces en el suelo. A través del análisis de Conglomerado Jerárquico y de Ligamiento Completo sobre la base de la distancia Euclidiana, los genotipos se reunieron en dos grupos según los índices de tolerancia medidos en las etapas iniciales del desarrollo de las plantas y en tres sobre la base de los índices medidos en la cosecha, indicando la existencia de variabilidad genética. en los materiales introducidos, destacándose las variedades INIFAT RM-26 e INIFAT RM-36 como las de mejor comportamiento, por lo que pueden ser introducidas en áreas con bajos suministros de agua. El valor del coeficiente de coincidencia W=0.82 reveló la existencia de un alto grado de congruencia entre las clasificaciones establecidas, lo que denota la posibilidad de complementar las evaluaciones de la tolerancia a la sequía con indicadores del crecimiento de las plántulas e indicadores agronómicos durante la cosecha.

  2. Ensayo de irritabilidad vaginal a un producto natural, obtenido a partir de Rhizophora mangle L. destinado al tratamiento de infecciones uterinas.

    Directory of Open Access Journals (Sweden)

    Félix Agüero, Carlos Bulnes, Reina Durand y Liseth García.

    2005-06-01

    Full Text Available En las últimas décadas, se observa un incremento en la tendencia a obtener productos de origen natural para el tratamiento de afecciones en animales y humanos. Una de las fuentes naturales explotadas en Cuba con este fin es la planta Rhizophora mangle L. conocida comúnmente como Mangle rojo. Sobre los resultados obtenidos en investigaciones previas, nos trazamos como objetivo de nuestro trabajo desarrollar un ensayo para evaluar el potencial irritante de una formulación de Rhizophora mangle L. como medicamento candidato al tratamiento de infecciones uterinas. El ensayo se realizó bajo los procedimientos establecidos en la norma ISO 10993-10. “Biological evaluation of medical devices. Part 10: Test for irritation and sensitization. European Committee for Standarization”. Se cumplieron los principios de las Buenas Prácticas de Laboratorio y los principios éticos para evitar sufrimiento a los animales durante la experimentación. El protocolo de investigación fue aprobado por el Comité Institucional de Ética del CENSA. Como resultado se observó ligera congestión e infiltración leucocitaria. Los índices de irritabilidad fueron de 4.0, 3.1, 2.3 y 0.5, para las concentraciones de 16, 24, 32 y 100 mg/mL, respectivamente. El producto no fue irritante para la mucosa vaginal y se observó una disminución del indicador en la medida que se incrementa la concentración de la formulación.

  3. Evaluación de tres dosis de un preparado microbiano, obtenido en Ecuador, en la respuesta productiva y sanitaria de cerdos en posdestete

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    Luis Gerardo Flores-Mancheno

    2015-07-01

    Full Text Available Para evaluar tres dosis de un preparado microbiano obtenido en el Ecuador (4x106 UFC de bacterias lácticas, 1,5x105 UFC de levaduras por cada mililitro, en el comportamiento productivo y de salud en cerdos durante la etapa post-destete, se aplicó un diseño completamente aleatorizado, con cuatro tratamientos y cuatro repeticiones por tratamiento: T1 concentrado, T2, T3, T4 (concentrado más 5 mL/kg de peso vivo (PV, 10 mL/kg PV 15 mL/kg PV del preparado microbiano, respectivamente. Se utilizaron 160 cerdos castrados del cruce Landrace x Large White con Blanco Belga x Pietrain, de 28 d de edad y con 6,99 kg de PV. El mayor peso vivo final y la mejor ganancia de peso total y diaria (P < 0,0001 se obtuvo en el grupo de cerdos donde se agregó 15 mL/kg PV del preparado microbiano, con valores de 25,78 kg, 18,78 kg y 447,25 g, respectivamente. En el mismo grupo experimental se encontraron las conversiones de materia seca, proteína bruta y energía metabolizable más eficientes 1,54 kg /kg PV y aumento de peso vivo de 383,92 g/kg PV y 23,16 MJ/kg PV, respectivamente. También en este grupo se registró la menor presencia de animales con diarrea (P < 0,0001 6,85%. Se concluye que la adición de 15 mL/kg PV mejora el comportamiento productivo y sanitario de cerditos destetados.

  4. Evaluación in vivo del efecto cicatrizante de un gel a base de quitosano obtenido de exoesqueleto de camarón blanco Litopenaeus vannamei

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    Heimy Franceline Martínez Sánchez

    2014-06-01

    Full Text Available Healing effect of a chitosan-based gel obtained from the exoskeleton of white shrimp Litopenaeus vannamei and its evaluation in vivoTítulo corto: Evaluación del quitosano como cicatrizanteResumen:  En México alrededor del 62 % de la población sufre de accidentes causantes de alteraciones en la piel como quemaduras, heridas y diabetes principalmente. Para atender esta problemática, se propone el uso de un gel de quitosano, obtenido del exoesqueleto de camarón ya que presenta actividad antimicrobiana e inmunológica acelerando la cicatrización. Se evaluó el efecto sinérgico sobre la velocidad de cicatrización, aplicándolo en heridas de 1 cm2 infringidas a 48 ratones albinos, agrupados en cuatro tratamientos; Quitosano 0.15 y 0.30 %, producto cicatrizante (Ketanserina al 2 % y blanco (testigos sin tratamiento. El tiempo para la cicatrización sin tratamiento y el producto comercial fue 14 días, teniendo el control un efecto cicatrizante del 0 %, mientras que los geles de quitosano 0.15 y 0.30 % cicatrizaron en 7 días (P> 0.05 con efecto cicatrizante del 58 % para el quitosano 0.15 y 64 % para el quitosano 0.30.Palabras clave: piel, heridas, gel, quitosano, cicatrización.Abstract: Skin problems in Mexico have steadily increased (62 % by burns, wounds and diabetes mainly. To solve this problem, chitosan can be implemented; this polysaccharide has an antimicrobial and immunology activity against bacteria and fungi, accelerating healing. Therefore, synergistic effect of chitosan gel on the rate of healing, obtained from the exoskeleton of shrimp was evaluated. This was tested by applying it 1 cm2 over inflicted wounds of 48 albino mice, of 45 days old and between 23 to 26 g of weight, during 14 days, and grouped into four treatments: 1 0.15 % chitosan 2 0.30 % chitosan, 3 commercial product 2 % Ketanserin and 4 A batch of untreated controls. The time required for healing without treatment was 14 days, and with the utilization of 0

  5. Efecto de la concentración de poliacrilamida sobre la calidad del depósito de cobre obtenido por refino electrolítico

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    Aragón, J.

    2013-12-01

    Full Text Available The effect of the additive non ionic polyacrylamide (PAM, was studied at the laboratory level, as refining crystalline grain in the copper electrorefining. Experiments were performed 24 h of electrolysis, using an electrolyte of copper sulphate acid, with 0.5 to 10 mgl-1 polyacrylamide at 55 °C and a current density of 260 Am-2. The effectiveness of these organic additives in copper electrorefining was determined by directly measuring the surface roughness of the copper deposit and contrasted with the results of other instrumental techniques (SEM and metallographic analysis. The results of the analysis SEM, metallographic analysis and measurement of the surface roughness of the copper deposit, show that to concentrations as low as 0.5 mgl-1 of this additive is manifested its property of tuner of grain. However, in the range of 7 to 10 mgl-1 of polyacrylamide, it reaches an optimum size of grain for the deposit of copper in the cathodes.El efecto del aditivo poliacrilamida no iónica (PAM, se estudió a nivel de laboratorio, como afinador de grano cristalino en el refino electrolítico del cobre. Se realizaron experimentos de electrólisis de 24 h, utilizando un electrolito de sulfato de cobre ácido, con 0,5 a 10 mgl-1 de poliacrilamida, a 55 °C y una densidad de corriente de 260 Am-2. La efectividad de este aditivo orgánico en la refinación electrolítica del cobre fue determinada mediante la medida de la rugosidad de la superficie del depósito de cobre y contrastada con los resultados de otras técnicas instrumentales (MEB y análisis metalográfico. Los resultados obtenidos del análisis MEB, análisis metalográfico y medición de la rugosidad superficial del depósito de cobre, muestran que a concentraciones tan bajas como 0,5 mgl-1 de este aditivo, se manifiesta su propiedad de afinador de grano. Sin embargo, en el rango de 7 a 10 mgl-1 de poliacrilamida, se alcanza un tamaño de grano óptimo para el depósito de cobre en el cátodo.

  6. Características químico-sensoriales de los aceites de oliva «Arbequina» obtenidos en distintas zonas de España

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    Touss, J.

    1997-12-01

    Full Text Available Within the quality virgin olive oils produced in Spain, Catalonia has two of the six currently existing Origin Denominations (Garrigues and Siurana. Their production of extra virgin oil proceeds of the «Arbequina» cultivar, approximately 8.000 tm, distributed between the CD «Garrigues», in Lleida (5.000 tm, and «Siurana» in Tarragona (3.000 tm. These oils are very appreciated at domestic as well as at international level because of their excellent taste. In the last years, this variety is being expanded in other regions of Spain (Andalusia, Aragon, etc. and over the worid (Argentina, France, etc.. The physico-chemical and sensory characteristics of «Arbequina» virgin olive oils produced are studied, mainly in Catalonia, Andalusia and Aragon. The obtained preliminary results indicate that some quality parameters of the «Arbequina» oil are variable, being cultivated in different environments, mainly certain fatty acids, polyphenols, oxidative stability and some sensory attributes of the oil.

    Dentro de los aceites de oliva vírgenes de calidad que se producen en España, Cataluña destaca por tener dos denominaciones de origen (Garrigues y Siurana de las seis actualmente existentes. La producción de aceite virgen extra de las mismas procede de la variedad «Arbequina», aproximadamente 8.000 tm, repartidas entre las D. O. «Garrigues», en Lleida (5.000 tm, y «Siurana» en Tarragona (3.000 tm. Estos aceites son muy apreciados tanto a nivel nacional como internacional por sus excelentes características organolépticas. En los últimos años, esta variedad se está extendiendo por España (Andalucía, Aragón, etc. y otros países del mundo (Argentina, Francia, etc.. Se estudian las características físico-químicas y sensoriales de los aceites de oliva vírgenes de la variedad «Arbequina» producidos, principalmente, en Cataluña, Andalucía y Aragón. Los resultados preliminares obtenidos indican que algunos parámetros del

  7. EVALUACIÓN CATALÍTICA DE ÓXIDOS POLICATIÓNICOS TIPO PEROVSKITA OBTENIDOS POR POLIMERIZACIÓN CON ÁCIDO CÍTRICO

    Directory of Open Access Journals (Sweden)

    Jairo Gómez Cuaspud

    2010-03-01

    Full Text Available En este trabajo se describe la preparación de la perovskita La0,75Sr0,25Co0,5Fe0,5O3, (LaSrCoFeO, empleando una ruta de química húmeda, mediante la polimerización con ácido cítrico, con el propósito de obtener materiales para potenciales aplicaciones electródicas en pilas de combustible de óxido sólido (SOFC; para ello, el sólido se caracterizó mediante difracción de rayos X (DRX, microscopia electrónica de barrido (SEM y área superficial específica mediante el método BET, permitiendo determinar la formación de una fase tipo perovskita concordante con el registro JCPDS: 089-1267; la textura y el relieve encontrados son característicos del método de síntesis, confiriéndole al sólido cierto grado rugosidad. El tamaño de cristalito, calculado con el programa Scherrer Calculator, confirmó la presencia de cristalitos nanométricos, mientras que la composición global determinada mediante microanálisis de rayos X de energía dispersiva (EDX, indicó una buena concordancia entre la composición propuesta y la obtenida. La evaluación catalítica se realizó utilizando la descomposición de peróxido de hidrógeno en medio alcalino; este procedimiento permitió determinar que la reacción es de pseudo primer orden con respecto al peróxido, suponiendo que la masa de catalizador y la concentración de la base no inciden sobre la velocidad de reacción. Las isotermas de actividad, la energía aparente de activación, y en general la actividad observada, guardan buena correspondencia con resultados obtenidos para la descomposición de H2O2 sobre otros sólidos.

  8. Análisis y predicción de lluvias intensas en la Comunidad Valenciana basados en la estimación del contenido de vapor de agua atmosférico obtenido con técnicas GNSS

    OpenAIRE

    Priego De Los Santos, Jose Enrique

    2012-01-01

    Priego De Los Santos, JE. (2012). Análisis y predicción de lluvias intensas en la Comunidad Valenciana basados en la estimación del contenido de vapor de agua atmosférico obtenido con técnicas GNSS [Tesis doctoral no publicada]. Universitat Politècnica de València. doi:10.4995/Thesis/10251/17805. Palancia

  9. Análisis estadístico de los registros de ruido electroquímico obtenidos en la corrosión del aluminio

    Directory of Open Access Journals (Sweden)

    Sánchez, A.

    2005-10-01

    , los cuales pueden reflejar cambios en el mecanismo de corrosión. Sobre todos estos parámetros destaca el uso de la resistencia de ruido. En este trabajo se ha llevado a cabo el tratamiento estadístico de los datos de ENM obtenidos cuando el aluminio es sometido a la acción a tres electrolitos diferentes, que provocan tres tipos distintos de corrosión: el agua destilada (pasividad, una disolución de cloruro de sodio (corrosión por picaduras y una disolución de hidróxido de sodio (corrosión generalizada o uniforme.

  10. COMPARACIÓN DEL ESTADIO FETAL OBTENIDO POSTMORTEM MEDIANTE DOS METODOS ANTROPOMETRICOS. COMPARISON OF FETAL STAGE OBTAINED POSTMORTEM BY TWO ANTHROPOMETRIC METHODS

    Directory of Open Access Journals (Sweden)

    Emanuel Repetto

    2011-03-01

    fetos: 1 grupo A (60 fetos estadificado ecográficamente y 2 grupo B (60 fetos estadificado por tabla de Hansmann. A ambos grupos se le realizaron múltiples mediciones siguiendo parámetros probados según la literatura internacional. Se utilizó calibre de precisión. Parámetros evaluados: longitud vertex-coxis, circunferencia cefálica, diámetro cefálico occipito-frontal, biparietal, longitud mentón-vertex, perímetro toráxico-transverso, circunferencia abdomi-nal y longitudes de brazo, antebrazo, mano, muslo, pierna y pie. Estos valores fueron agrupados por semanas, obteniéndose la media y aplicándose la prueba t de Student. Los resultados demostraron que la diferencia entre los parámetros medidos en el grupo A y en el grupo B eran significativas en todas las semanas, por lo que se observa disparidad en la determinación del estadio fetal por ecografía y los registros correspondientes a la medición vertex-coxis (tabla de Hansmann postmortem. Concluímos que los resultados obtenidos por ambas modalidades de medición son diferentes para una misma edad gestacional y, por ende, resultaría más apropiado referirse a fetos con ciertas dimensiones según alguno de estos parámetros que a “edad gestacional”.

  11. Estudio de polvos y recubrimientos metaestables de NiTi obtenidos por proyección térmica de plasma

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    Cano, I. G.

    2008-06-01

    una mezcla directa de partículas de níquel y de titanio, mientras que el otro consiste en una aleación obtenida a través de un proceso de atomización por gas. Ambos polvos fueron proyectados, obteniéndose mejores resultados para el polvo atomizado, ya que ha permitido la obtención de recubrimientos en los que la fase de NiTi es la mayoritaria con un mínimo contenido en óxido. Para lograrlo, se ensayaron diferentes parámetros de proyección.La caracterización microestructural se llevó a cabo mediante microscopía electrónica de barrido con un sistema de microanálisis acoplado. Además, los estudios de difracción de rayos X permiten concluir que el ensanchamiento de los picos puede demostrar la existencia de metaestabilidad en los recubrimientos obtenidos.

  12. Evaluación de la actividad entomopatogénica de hongos obtenidos del Páramo de Guerrero (Finca Puente de Tierra Zipaquirá, Colombia

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    Sánchez Nieves Jimena

    2006-06-01

    Full Text Available El estudio y conservación de enemigos naturales en agroecosistemas conlleva a largo plazo a la regulación de
    insectos plaga, proporcionando un ambiente apropiado para incrementar la abundancia y eficacia de predadores
    y parásitos. El control biológico constituye una estrategia efectiva dentro de programas de manejo integrado de plagas y enfermedades (MIPE, garantizando control a bajo costo y con un mínimo o inexistente impacto ambiental. El objetivo del presente estudio fue aislar, determinar y evaluar la actividad entomopatógena de hongos obtenidos de suelos (en dos profundidades: 0-20 y 20-40 cm de bosque, cultivos de papa y zonas de descanso, en la finca Puente de Tierra, páramo de Guerrero; utilizando larvas de Galleria mellonella (insecto cebo para su aislamiento y adultos de Tecia solanivora (Povolny para los bioensayos de actividad, calculando tiempos de letalidad 50 y 90. La mayoría de los aislamientos de hongos patógenos y no patógenos se obtuvieron a partir del bosque (no intervenido, en la profundidad de 0-20 cm. En el bioensayo, se observaron resultados positivos para los géneros Fusarium, Paecilomyces y Cordyceps, los cuales son ampliamente reconocidos como entomopatógenos (Lacey, 1997, confirmando su potencial como controladores biológicos de plagas asociadas a cultivos de papa en la zona de estudio. El cultivo de papa involucra prácticas agrícolas y de manejo postcosecha dentro de las cuales, esta involucrado el uso de plaguicidas , el cual representa casi el 20% de los costos totales de la producción del cultivo, siendo por tradición la principal alternativa de control ante los problemas fitosanitarios (Rodríguez, 1996. No obstante, el empleo simultáneo de estrategias de
    control biológico es de gran importancia dentro del contexto de MIPE. Los hongos juegan un papel muy importante en la regulación de poblaciones de insectos, debido a que existen algunos con gran potencial para el control de

  13. Propiedades químicas y química-físicas de derivados estructurales de ácidos húmicos obtenidos de vermicompost. Actividad biológica

    OpenAIRE

    Rafael Huelva López; Dariellys Martínez Balmori; Andrés Calderín García; Orlando L. Hernández González; Fernando Guridi Izquierdo

    2013-01-01

    La modificación química de los ácidos húmicos (AH) puede ser usada como una herramienta para entender su estructura química, la que es muy compleja. Nuevos resultados muestran que existe una relación entre sus funciones y propiedades químicas modificadas con cambios en la actividad biológica que manifiestan sobre el crecimiento de las plantas. En el presente trabajo se utilizaron reacciones químicas de acetilación, metilación y amonificación para modificar la estructura de los AH obtenidos de...

  14. Análisis del funcionamiento de varias instalaciones de refrigeración solar y comparación de los resultados obtenidos con un modelo de simulación existente

    OpenAIRE

    Martínez Sánchez, Rafael

    2011-01-01

    El objeto de este proyecto incluye el análisis del funcionamiento de las instalaciones de refrigeración solar de la región de Murcia propiedad de ARGEM a partir de los datos de la monitorización y la obtención de conclusiones tanto técnicas como económicas. En un segundo lugar se seleccionarán datos representativos de las instalaciones y se compararán con los obtenidos en el modelo de TRNSYS elaborado por la UPCT para la simulación de instalaciones de refrigeración solar, tras ...

  15. DETERMINACIÓN DE FENOLES TOTALES EN DERIVADOS LÍGNICOS OBTENIDOS DEL “LICOR NEGRO” COMO ALTERNATIVA DE PRODUCCIÓN // DETERMINATION OF TOTAL PHENOL DERIVATIVES OBTAINED FROM LIGNIN "BLACK LIQUOR" AS ALTERNATIVE TO PRODUCTION

    Directory of Open Access Journals (Sweden)

    María José López Villalobos

    2015-06-01

    Full Text Available Lignin is an industrial waste being worthless in papermaking byproduct of black liquor obtained from the pulping process in some Venezuelan plants. The black liquor is obtained from the Kraft pulping process to extract lignin sulphite by acid precipitation and quantify the amount of total phenols in such lignin products used in this study. Spectrophotometry Molecular absorption in the UV-Visible and Infrared Spectroscopy (FTIR region were used to carry out these study techniques. The products obtained in the study had the same signs than commercial lignin (LA, along with the extracted lignin present little degradation HCl, confirmed by infrared spectra. Also, the amount of total phenols was quantified in derivative lignin obtained using the Folin-Ciocalteu. In the sulphite process extracted lignin with acetic acid derivative contains more phenols, and in the Kraft process, the derivative lignin extracted with fewer nitric acid present. The amount of total phenolics present in these derivatives are good for making antiseptics, detergents, nylon, resin and many industrial products. // RESUMEN La lignina es un subproducto del licor negro obtenido del proceso de despulpado en algunas plantas de Venezuela, siendo un desecho industrial que carece de valor en la fabricación de papel. En este estudio se utilizó el licor negro obtenido de los procesos de pulpado Kraft y Sulfito para extraer la lignina mediante precipitaciones ácidas y cuantificar la cantidad de fenoles totales en dichos productos lígnicos. Para llevar a cabo este estudio, se utilizaron las técnicas de Espectrofotometría de Absorción Molecular en la región UV-Visible y la Espectroscopia de Infrarrojo (FTIR. Los productos obtenidos en el estudio presentaron señales similares que la lignina comercial (LA, además la lignina extraída con HCl presentó poca degradación, corroborado por los espectros infrarrojos. Asimismo, se cuantificó la cantidad de fenoles totales en los

  16. Procedimiento para la recuperación de cromo y bioproductos a partir de residuos peleteros, instalación para llevarlo a cabo y los productos así obtenidos

    OpenAIRE

    Cot Cosp, Jaime; Marsal, Agustí; Manich, Albert M.; Celma Serra, Pere; Cot Gores, Jaume; Fernández Hervás, Fernando

    2007-01-01

    Procedimiento para la recuperación de cromo y bioproductos a partir de residuos peleteros, instalación para llevarlo a cabo y los productos así obtenidos. La invención describe un procedimiento de recuperación de cromo y de bioproductos a partir de un residuo peletero, basado en la oxidación del cromo (III) a cromo (VI) usando peróxidos en un medio alcalino y una instalación industrial para llevarlo a cabo. El cromo y los bioproductos pueden ser utilizados de nuevo, re...

  17. Influence of the hybrid material size in silicon oxycarbide materials characteristics; Influencia del tamano del material hibrido en las caracteristicas de los oxicarburos de silicio obtenidos

    Energy Technology Data Exchange (ETDEWEB)

    Mazo, M. A.; Palencia, C.; Nistal, A.; Rubio, F.; Rubio, J.; Oteo, J. L.

    2012-11-01

    In this work has been investigated the influence of the TEOS/PDMS hybrid size during the pyrolysis process to obtain the related silicon oxycarbide glasses. Hybrids monolithic pieces (100 mm x 50 mm x 5 mm), were crushed (1 mm x 1 mm x 1 mm) and grounded in agate or attrition to 16 and 3 {mu}m, respectively. Then, they were pyrolyzed at 1100 degree centigrade to obtain silicon oxycarbide glasses (SiOC). These materials present structural and microstructural differences. The monolithic sample showed the highest %C into the silica network (34 %), and after grounding in agate mortar decreased to 26 %. However the attrition milled sample reached %C values similar to the monolithic (32 %). This agrees with FT-IR band at 880 cm-1 assigned to Si-C bonds formation and related to higher carbon content into silica network. The carbon free phase displays a domain size of 3.44 nm which increased to 3.66 nm for the attrition milled. This result is due to a higher graphitization degree. The SiOC monolithic sample morphology displays spherical interconnected particles with pores of 12 {mu}m. This morphology disappeared for the SiOC attrition milled sample, formed by irregular particles of 3 {mu}m. (Author) 38 refs.

  18. Crude extracts of Drimys winteri bark to inhibit growth of Gaeumannomyces graminis var. tritici Inhibición del crecimiento de Gaeumannomyces graminis var. tritici empleando extractos obtenidos de corteza de Drimys winteri

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    Nelson Zapata

    2011-03-01

    Full Text Available The aim of this study was to assess the effect of Drimys winteri J.R. Forst. & G. Forst. bark and its extracts, obtained sequentially with n-hexane, acetone, and methanol, against Gaeumannomyces graminis var. tritici (Ggt. Ground bark of D. winteri was mixed with potato dextrose agar growth media at concentrations of 250, 500, 1000, 2000, and 4000 mg L-1 in Petri plates. Each extract was mixed at concentrations of 100, 200, 400, and 800 mg L-1. Petri plates were inoculated in the center with a 5-mm mycelium disk and were incubated at 24 ± 1 ºC. Daily measurements of mycelium radial growth were taken to determine growth rate and growth inhibition (%. A ground bark concentration of 978 mg L-1 was needed to inhibit Ggt growth by 50%, while extracts obtained with n-hexane and acetone only required 198 and 234 mg L-1, respectively. The methanol extract only inhibited Ggt growth by 33% when tested at the highest concentration. In conclusion, ground bark and crude extracts, obtained sequentially with n-hexane, acetone, and methanol, from D. winteri bark inhibit Ggt growth when applied in vitro. The n-hexane extract showed the highest inhibitory growth activity.El objetivo de esta investigación fue evaluar la actividad de la corteza de Drimys winteri J.R Forst. & G. Forst. y sus extractos obtenidos secuencialmente con n-hexano, acetona y metanol sobre el crecimiento in vitro de Gaeumannomyces graminis var. tritici (Ggt. Con este propósito se mezclaron en placas Petri, corteza molida de D. winteri con medio de crecimiento agar papa dextrosa a concentraciones de 250, 500, 1000, 2000 y 4000 mg L-1. Cada extracto fue mezclado a concentraciones de 100, 200, 400 y 800 mg L-1. Las placas se inocularon en su centro con un disco de 5 mm de micelio de Ggt y se incubaron a 24 ± 1 ºC. Diariamente se midió el crecimiento radial del micelio, se determinó velocidad de crecimiento e índice de inhibición del crecimiento (%. Para inhibir el crecimiento de Ggt

  19. Mechanical and trybological characterization of ceramic materials obtained of mine solid wastes; Caracterizacion mecanica y tribologica de materiales ceramicos obtenidos de residuos solidos mineros

    Energy Technology Data Exchange (ETDEWEB)

    Soto T, J.L

    2003-07-01

    A discussion of the physical, mechanical and tribological characterization of the ceramics Jaar, Jaca and Vijaar is presented in this work. They have been obtained from the industrial residuals, coming from metals and sand of the mining industry in Pachuca Hidalgo, Mexico. The methodology followed for the obtention and characterization of these ceramics consists on eliminating the cyanides from the tailings through columns coupled with a system controlled with thermostats. Then, the chemical composition is analysed with spectrometry emission of plasma and scanning electronic microscopy. Then the ceramics are produced. The base material is agglutinated with clay or kaolin. For this purpose, it was used a sintering processes and isothermal compacting in hot condition. Finally, the physical, chemical, mechanical and tribological properties of these new products are determined. Carbon, oxygen, sodium, magnesium, aluminium, manganese, silicon, potassium, phosphor, calcium, titanium, iron, molybdenum, silver and gold are in the chemical composition or ceramic analysed. Also these are heterogeneous mixture of clay and kaolin. The cyanide was eliminated. The results show that Vijaar has better wear resistances to the waste; this was demonstrated in tribology tests. They were not perforated with the abrasive particles. Also, they have high hardness and they can to support more loads in compression than Jaar and the Jaca. Consequently, they are less fragile and, therefore, they can tolerate bending stresses and bigger impact loading. (Author)

  20. Estudio del comportamiento del sistema Amno3-Amoo4 (A = Ba, Sr) obtenido por el método de polimerización con ácido carboxílico

    OpenAIRE

    Argote Salgado, Miguel Gregorio

    2011-01-01

    Los datos de difracción de rayos X, obtenidos para los sistemas tratados a 750 °C durante 2 horas, derivados del presente estudio confirmaron la obtención de una fase tipo perovskita en los sistemas AMnO3 y AMoO4 (A = Sr, Ba). La cual, persistió hasta temperaturas de 1150 °C, por un periodo de 6 horas, en atmósfera de aire; sin embargo, un análisis más cuidadoso permitió visualizar la evolución de los sistemas hacia los compuestos Sr2MnMoO6 y Ba2MnMoO6. Adicionalmente, se puso en evidencia q...

  1. Carbon Carbon Composites: An Overview .

    OpenAIRE

    G. Rohini Devi; K. Rama Rao

    1993-01-01

    Carbon carbon composites are a new class of engineering materials that are ceramic in nature but exhibit brittle to pseudoplastic behaviour. Carbon-carbon is a unique all-carbon composite with carbon fibre embeded in carbon matrix and is known as an inverse composite. Due to their excellent thermo-structural properties, carbon-carbon composites are used in specialised application like re-entry nose-tips, leading edges, rocket nozzles, and aircraft brake discs apart from several indust...

  2. Determinación de la densidad de entrecruzamiento de poliuretanos obtenidos a partir de aceite de ricino modificado por transesterificación Determination of crosslink density of polyurethanes obtained from castor oil modified by transesterification

    Directory of Open Access Journals (Sweden)

    Manuel F. Valero

    2009-01-01

    Full Text Available Se obtuvo una gama de polioles a partir del aceite de ricino modificado por transesterificación con pentaeritriol y glicerina. Los productos resultantes fueron caracterizados físico-químicamente. Se sintetizaron elastómeros de poliuretano a partir de los polioles derivados del aceite de ricino modificado. La densidad de entrecruzamiento se determinó por ensayos de hinchamiento a partir de la ecuación de Flory-Rehner apoyada en la espectroscopia MALDI TOF MS para determinar la estructura química de la unidad repetitiva promedio del poliuretano. Se estudió la variación de la densidad de entrecruzamiento de los poliuretanos con base en el índice de hidroxilo del poliol utilizado en la síntesis. Los resultados muestran que los PU obtenidos a través de la modificación del aceite con pentaeritriol tienen una mayor densidad de entrecruzamiento que los PU obtenidos a partir del aceite original y de los polioles derivados de la reacción de transesterificación del aceite con glicerina, debido a que estos polioles poseen una mayor funcionalidad hidroxílica.Two series of polyols were obtained from castor oil modified by transesterification with various amounts of pentaerythritol and glycerol. The resultant polyol properties were characterized as a function of the hydroxyl functionality. Polyurethane elastomers (PU were synthesized from the two series of polyols obtained. The crosslink density of those polyurethanes was determined by swelling tests data adjusted to the Flory-Rehner's equation and according to the elasticity theory. The variation of the crosslink density of polyurethanes was studied by following the hydroxyl value of the modified polyol utilized in the synthesis and based on the average structure of each polyurethane repeating unit, as determined by the method of matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI TOF MS. The results show that the PU obtained through castor oil modified with

  3. Actividad Antioxidante de Hidrolizados Enzimáticos de Plasma Bovino Obtenidos por Efecto de Alcalasa® 2.4 L Antioxidant Activity of Bovine Plasma Enzymatic Hydrolysates Obtained by Effect of Alcalase® 2.4 L

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    Leidy J Gómez

    2013-01-01

    Full Text Available Se ha evaluado la actividad antioxidante de hidrolizados de plasma de bovino (HPB obtenidos con Alcalasa 2.4 L a diferentes grados de hidrólisis. Los HPB se fraccionaron a través de membranas de ultrafiltración y se purificaron por cromatografía de intercambio iónico, con una posterior cromatografía líquida de alta eficiencia en fase reversa. Los resultados mostraron que los HPB obtenidos bajo las condiciones de hidrólisis planteadas, poseen una fuerte capacidad de captación de radicales ácido 2,2´-azino-bis(3-etilbenzotiazolin-6-sulfónico y un alto poder de reducción comparado con las proteínas de plasma no hidrolizadas. Se encontró además, que la actividad antioxidante se incrementa en función del grado de hidrólisis, y que dicha actividad se mantiene después de someter los hidrolizados a condiciones de digestión in-vitro. Los procesos descritos permiten obtener un péptido con una actividad antioxidante similar a la presentada por algunos antioxidantes comerciales.The antioxidant activity of bovine plasma hydrolysates (BPH obtained with Alcalase 2.4 L at different hydrolysis degrees was evaluated. The hydrolysates were fractioned through ultrafiltration membranes and were purified by ion-exchange chromatography, with subsequent reverse-phase high performance liquid chromatography. The results showed that the hydrolysates of bovine plasma obtained under the established hydrolysis conditions, had strong scavenging ability on 2,2-azino bis-(3-ethylbenzothiazoline-6-sulfonic acid free radicals and a great reduction power compared with proteins of non-hydrolyzed plasma. Additionally, it was found that the antioxidant activity increases as function of the hydrolysis degree, and that this activity remains after in-vitro digestion. The processes described allow obtaining a peptid with antioxidant activities similar to that of conventional commercial antioxidants.

  4. Carbon Carbon Composites: An Overview .

    Directory of Open Access Journals (Sweden)

    G. Rohini Devi

    1993-10-01

    Full Text Available Carbon carbon composites are a new class of engineering materials that are ceramic in nature but exhibit brittle to pseudoplastic behaviour. Carbon-carbon is a unique all-carbon composite with carbon fibre embeded in carbon matrix and is known as an inverse composite. Due to their excellent thermo-structural properties, carbon-carbon composites are used in specialised application like re-entry nose-tips, leading edges, rocket nozzles, and aircraft brake discs apart from several industrial and biomedical applications. The multidirectional carbon-carbon product technology is versatile and offers design flexibility. This paper describes the multidirectional preform and carbon-carbon process technology and research and development activities within the country. Carbon-carbon product experience at DRDL has also been discussed. Development of carbon-carbon brake discs process technology using the liquid impregnation process is described. Further the test results on material characterisation, thermal, mechanical and tribological properties are presented.

  5. APLICACIÓN DE TÉCNICAS MULTIVARIADAS EN LA CLASIFICACIÓN MORFOAGRONÓMICA DE GENOTIPOS DE ARROZ OBTENIDOS EN LA ESTACIÓN EXPERIMENTAL "LOS PALACIOS"

    Directory of Open Access Journals (Sweden)

    R. Morejón

    2001-01-01

    Full Text Available Se evaluaron caracteres agronómicos y morfológicos, con el objetivo de clasificar 45 genotipos de arroz, parte del material genético obtenido por diferentes técnicas de mejoramiento en la Estación Experimental "Los Palacios", que se sembraron de acuerdo a un Diseño Aumentado Modificado (DAM empleando el Sistema de evaluación estándar para arroz y el Formulario de descripción varietal para su evaluación. Para la clasificación de los genotipos, la matriz de datos obtenida fue procesada mediante los Análisis de Componentes Principales, de Conglomerados y Discriminante, presentándose correlaciones significativas entre las variables y agrupándose las líneas y variedades en 10 clases. La existencia de diferencias sustanciales en el germoplasma analizado y el empleo correcto de las técnicas multivariadas garantiza el desarrollo de futuros programas de mejoramiento.

  6. ACERO GALVANIZADO PRE-TRATADO CON PELÍCULAS HÍBRIDAS OBTENIDO POR RECUBRIMIENTO POR INMERSIÓN: INFLUENCIA DE LA VELOCIDAD DE RETIRADA DEL SUBSTRATO DEL SOL

    Directory of Open Access Journals (Sweden)

    Sandra Kunst

    2013-01-01

    Full Text Available En el presente trabajo, el acero galvanizado fue revestido con una película de silano obtenido a partir de un sol constituido por los precursores silano 3-(trimetoxisililpropil metacrilato (Tmspma y Tetraetoxisilano (Teos con adición de nitrato de cerio [0,01 M]. Se emplearon diferentes velocidades de retirada del sol (10, 20 y 30 cm.min-1, la caracterización de las películas fue realizada por Microscopía Electrónica de Barrido (MEB, perfilometría, ángulo de mojabilidad, potencial de circuito abierto, espectroscopia de impedancia electroquímica y polarización potenciodinámica. Los resultados muestran que la velocidad de retirada influye en el comportamiento electroquímico de las películas, las películas con mejor resistencia a la corrosión se obtiene con menores velocidades de retirada (10 y 20 cm.min-1.

  7. Propiedades químicas y química-físicas de derivados estructurales de ácidos húmicos obtenidos de vermicompost. Actividad biológica

    Directory of Open Access Journals (Sweden)

    Rafael Huelva López

    2013-01-01

    Full Text Available La modificación química de los ácidos húmicos (AH puede ser usada como una herramienta para entender su estructura química, la que es muy compleja. Nuevos resultados muestran que existe una relación entre sus funciones y propiedades químicas modificadas con cambios en la actividad biológica que manifiestan sobre el crecimiento de las plantas. En el presente trabajo se utilizaron reacciones químicas de acetilación, metilación y amonificación para modificar la estructura de los AH obtenidos de vermicompost de estiércol vacuno, los que se evaluaron por su contenido de C, coeficiente E4/E6 y su acidez. En los derivatizados y el AH sin derivatizar se analizaron los cambios estructurales mediante la Espectroscopia Infrarrojo de Reflactancia Difusa con Transformada de Fourrier (DRIFT y a través de sus espectros los índices de hidrofobicidad (IH y de condensación (IC de las moléculas. Los resultados muestran cambios importantes en todos los indicadores estudiados de manera diferenciada en dependencia del tipo de agente derivatizante. La respuesta encontrada en el bioensayo para Ácido Indol Acético (AIA mostró incrementos en el contenido equivalente del biorregulador a favor de los derivados estructurales y por encima de la actividad encontrada para el AH sin derivatizar.

  8. Sorption Thermodynamics of Soursop Powders Obtained by Different Dehydration Technologies / Termodinámica de Sorción de Polvos de Guanabana Obtenidos por Diferentes Tecnologías de Deshidratación

    Directory of Open Access Journals (Sweden)

    Adela Ceballos Peñaloza

    2013-12-01

    Full Text Available The soursop (Annona muricata L. is a perishabletropical fruit with high nutritional value. The aim of this workwas to evaluate the sorption thermodynamics of soursop powderswith maltodextrin (MD, obtained by different drying technologies,thus allowing understanding the mechanisms that govern thisprocess. Adsorption isotherms of freeze dried (FD, spray drying(SD and vacuum drying (VD powders were determined at 20, 30,40 and 50 °C by using the static gravimetric method. The resultsshowed that the better fits the adsorption experimental data isthe GAB model (R2>0.9893. The influence of the drying system inthe model parameters was also shown. The monolayer moisturevalues between 5.28 and 9.30% (kg water/kg d.s were within thereported range for dehydrated food. /La guanábana (Annona muricata L. es una frutatropical perecedera y de gran valor nutricional. El objetivo deéste trabajo fue evaluar la termodinámica de sorción de polvosguanábana con maltodextrina (MD obtenidos por diferentestecnologías de secado, lo que permite la comprensión de losmecanismos que regulan este proceso. Se determinaron lasisotermas de adsorción por método gravimétrico estático a 20, 30,40 y 50 °C, para polvos secados por liofilización (FD, aspersión(SD y vacío (VD. Los resultados mostraron que el modelo de GABse ajustó a los datos experimentales de adsorción (R2>0,9893.Se mostró la influencia del sistema de secado en los parámetrosdel modelo. Los valores de humedad de la monocapa, entre 5,28y 9,30% (kg de agua/kg s.s, se encuentran dentro de los rangosreportados para alimentos deshidratados.

  9. Estudio de los parámetros que afectan al contenido de deoxinivalenol en cereales o alimentos a base de cereales obtenidos en comercios de Valencia (España.

    Directory of Open Access Journals (Sweden)

    PJ Hernández-Rodríguez

    2016-01-01

    Full Text Available Las micotoxinas son metabolitos fúngicos que aparecen comúnmente como contaminantes de muchos cereales y pueden causar una amplia variedad de efectos tóxicos. En el presente estudio, se analizó un total de 182 muestras de diferentes cereales (arroz, trigo, maíz, avena, espelta, soja y tapioca obtenidos en establecimientos de la Comunidad Valenciana (España. Se examina la presencia de deoxinivalenol (DON y se realiza un estudio estadístico de las muestras según el tipo de cultivo (orgánico o convencional, su composición, el tipo de producto y la marca (comercial o blanca para estimar si estos parámetros influyen en la concentración de DON. Del total de muestras, 111 estaban contaminadas con DON, pero en concentraciones inferiores a los límites permitidos por la legislación europea. Se observó mayor incidencia de DON en muestras de trigo (80% seguidas de maíz (35% y arroz (13%, pero sin diferencia significativa (p>0,05 entre el tipo de cereal; ni con la práctica agrícola. Sin embargo, los resultados demostraron que el tipo de producto en el cereal procesado (p<0,001; los productos a base de lluvia y sémola presentaran valores mayores de DON que los fideos, los componentes del alimento procesado (p<0,01; los niveles de DON eran superiores en las rosquilletas de pan simples respecto a las rosquilletas con queso y con chocolate y la marca (p<0,05; las marcas blancas contienen más DON que las comerciales si influyen en los niveles de DON hallados en las muestras de trigo.

  10. Lípidos estructurados obtenidos por interesterificación de las mezclas binarias y ternarias de las grasas de palma, semilla de palma y triglicéridos de cadena media

    Directory of Open Access Journals (Sweden)

    Sotero Solis, Víctor Erasmo

    2001-08-01

    Full Text Available Structured lipids are modified triacylglycerols to alter the fatty acid composition and/or their distribution into the glycerol molecules, by using enzymatic or chemical methods. Some of them can be classified as functional foods or nutraceuticals because they are directly associated to the prevention and treatment of many diseases. The objectives of this paper were to obtain and to characterize structured lipids by chemical interesterification of binary and ternary mixtures of vegetable fats (palm and palm kernel and medium chain triacylglycerols (Trigliceril CM. Ten samples consisting of three individual samples, three binary mixtures, and four ternary mixtures were studied. The fatty acid composition, solid fat content and consistency at the temperatures from 10ºC to 35ºC were analysed. A mathematical model of multiple regression of the special cubic type was applied, and from the significant coefficients triangular diagrams were confectioned, which indicate curves of levels. The results showed that the interactions between the three components were not significant. The solid fat content depended on the palm and palm kernel fats, and on the binary interactions between them. The negative coefficients for the interactions showed an antagonic effect, which is characteristic of eutectic interactions between fats.Los lípidos estructurados son triglicéridos modificados por la alteración de su composición en cuanto a los ácidos grasos y/o su distribución en las moléculas de glicerol, por métodos químicos o enzimáticos. Son obtenidos por interesterificación química o enzimática. Algunos de estos lípidos pueden ser clasificados como alimentos funcionales o nutracéuticos, por estar directamente asociados a la prevención o tratamiento de diversas enfermedades. Los objetivos de este trabajo fueron el de obtener y caracterizar los lípidos estructurados por medio de la interesterificación química de las mezclas binarias y ternarias

  11. Actividad fitotóxica de un extracto N-Hexano obtenido de la corteza de Drimys Winteri sobre cuatro especies de malezas Phytotoxic activity of N-Hexane extract obtained from Drimys Winteri bark on four weeds

    Directory of Open Access Journals (Sweden)

    N. Zapata

    2011-06-01

    Full Text Available El objetivo de esta investigación fue determinar el efecto fitotóxico de un extracto obtenido con n-hexano de la corteza de Drimys winteri sobre la germinación y el crecimiento de Convolvulus arvensis, Setaria pumila, Daucus carota y Cichorium intybus. El efecto fitotóxico del extracto sobre la germinación de las malezas se determinó mediante bioensayos en placas de Petri y la aplicación del extracto en el medio de germinación en concentraciones de 100 a 1.000 mg L-1. En bioensayos en macetas, se determinó el efecto fitotóxico del extracto sobre la emergencia y crecimiento de las plántulas de malezas, en los cuales se aplicó el extracto mezclado con el sustrato de cultivo en concentraciones de 500 a 4.000 mg kg-1. También se determinó el efecto fitotóxico del extracto asperjado sobre plantas de malezas en concentraciones de 800 a 6.400 mg L-1. En los ensayos de germinación, el extracto retrasó la germinación y redujo el crecimiento de tallo y radícula de todas las malezas, el porcentaje de germinación disminuyó en todas las malezas, excepto en C. arvensis. La aplicación del extracto al sustrato de cultivo disminuyó y retrasó la emergencia de todas las malezas. Las plantas tratadas con extracto presentaron menor altura y hubo disminución de la biomasa acumulada. De igual modo, la aplicación del extracto al follaje de las malezas redujo la altura y la biomasa acumulada y llegó a causar la muerte de C. intybus, S. pumila y D. carota.The objective of this research was to determine the phytotoxic effect of the n-hexane extract obtained from the bark of Drimys winteri on germination and growth of Convolvulus arvensis, Setaria pumila, Daucus carota and Cichorium intybus. The phytotoxic effects of the extract on the germination of weeds were determined by bioassays in Petri dishes, adding the extract on the germination medium at concentrations of 100 to 1,000 mg L-1. The phytotoxic effects of the extract on the emergence and

  12. Potenciales Evocados Somatosensitivos (PESS obtenidos por estimulación del nervio Mediano (registros espinal y craneano en caninos Somatosensory Evoked Potentials Obtained by Stimulating the Median Nerve (Spinal Cord and Cranial Recordings in Dogs

    Directory of Open Access Journals (Sweden)

    F.C Pellegrino

    2005-12-01

    Full Text Available Se investigaron los PESS espinal y craneano y su génesis por estimulación del nervio mediano en 22 perros sanos cuya edad promedio fue 7 años. La velocidad de conducción (VC del nervio surgió del cociente entre la distancia desde el estímulo al registro espinal y la latencia del pico negativo de la onda obtenida. Se obtuvo el tiempo de conducción central (TCC midiendo la diferencia entre las latencias de los potenciales craneano y espinal. Se emplearon electrodos de aguja entre C7-T1 y en la piel del cráneo contralateralmente al estímulo. El potencial espinal mostró una primera deflexión positiva, seguida por una negativa finalizando con una positiva.La latencia media al pico negativo fue de 4.95+/-0.92ms. La media para la VC del nervio fue 60.79+/-13.53m/s. El potencial craneano tuvo forma de "w". La latencia media al pico negativo fue de 14.62+/-1.83ms. El TCC medio fue de 9.67+/-2.02ms. En 6 perros la estimulación se hizo también más distalmente, permitiendo medir la VC segmentaria del nervio; la media obtenida fue de 59.83+/-21.44m/s, que no difirió significativamente de la primera. El potencial espinal probablemente surja de la sumación espacial de la actividad de diferentes estructuras ubicadas en el lugar del registro, mientras que el obtenido en el cráneo sea debido a la acción de las conexiones tálamo-corticales y de la corteza de recepción.We investigated SSEPs in 22 normal dogs of both sexes (12 females, aged between 3 and 14 years (mean: 7 +/- 4 years old by recording the electrical signal at the spinal cord (L7-S1 and L5-L6 and at the scalp (frontoparietal region in response to median nerve stimulation. Conduction velocity (CV of median nerve and its roots was calculated, measuring the distance between the stimulating cathode and the recording electrode, and dividing it into the latency of the of the spinal cord arrival corresponding negative peak. Central conduction time (CCT was estimated subtracting the

  13. Caracterización físico-mecánica, térmica y morfológica de polímeros de redes interpenetradas con base en poliuretano obtenido a partir de aceite de ricino y almidón modificados/polimetilmetacrilato (PMMA)

    OpenAIRE

    Manuel F. Valero; Jorge E. Pulido; Álvaro Ramírez; Diana C. Camargo; Daniel Navas

    2011-01-01

    El aceite de ricino se modificó por transesterificación con pentaeritritol. Paralelamente, se utilizó la reacción de glucosilación con glicerol para dividir el almidón en unidades monosacáridos. El glucósido obtenido reaccionó por transesterificación con el aceite modificado por transesterificación con pentaeritritol. Se determinó el índice de hidroxilo de los poliol-glucósidos en función del contenido de pentaeritritol y almidón utilizados en la síntesis. Se sintetizaron redes interpenetrada...

  14. Filamentos elásticos de elastolefina de alta durabilidad obtenidos a partir de copolímeros de bloque de etileno-octeno de baja densidad mediante la tecnología de polimerización por transferencia de cadena para aplicaciones en indumentaria de uso profesional

    OpenAIRE

    Verdú Blasco, Pau

    2010-01-01

    En la actualidad el mercado carece de prendas elásticas para uso profesional puesto que los elastanos habitualmente utilizados son inestables frente a altas temperaturas y químicos agresivos, e.g. termofijado, mantenimiento de indumentaria industrial etc. Recientemente se han venido utilizado filamentos olefínicos obtenidos a partir de copolímeros al azar de etileno-octeno (Dow XLA fibers producidos por The Dow Chemical Company). Aunque más resistentes a las temperaturas...

  15. Porous carbons

    Indian Academy of Sciences (India)

    Satish M Manocha

    2003-02-01

    Carbon in dense as well as porous solid form is used in a variety of applications. Activated porous carbons are made through pyrolysis and activation of carbonaceous natural as well as synthetic precursors. Pyrolysed woods replicate the structure of original wood but as such possess very low surface areas and poor adsorption capacities. On activation, these exhibit increased adsorption volumes of 0.5–0.8 cm3 /gm and surface areas of 700–1800 m2 /gm depending on activation conditions, whether physical or chemical. Former carbons possess mixed pore size distribution while chemically activated carbons predominantly possess micropores. Thus, these carbons can be used for adsorption of wide distributions of molecules from gas to liquid. The molecular adsorption within the pores is due to single layer or multilayer molecule deposition at the pore walls and hence results in different types of adsorption isotherm. On the other hand, activated carbon fibres with controlled microporous structure and surface area in the range of 2500 m2 /gm can be developed by controlled pyrolysis and physical activation of amorphous carbon fibres. Active carbon fibres with unmatchable pore structure and surface characteristics are present and futuristic porous materials for a number of applications from pollution control to energy storage.

  16. Microstructural evolution of SiC/Cu-Si composites obtained through reactive infiltration; Evolucion microestructural de composites SiC/aleaciones CuSi obtenidos a traves de infiltracion ractiva

    Energy Technology Data Exchange (ETDEWEB)

    Cornejo, J.; Ordonez, S.; Iturriza, I.

    2010-07-01

    The microstructural evolution of composites of SiC/Cu-Si alloys obtained through process of reactive infiltration to 1400 degree centigrade was studied. Three zones were detected in the obtained composites: the reaction zone, the transition zone and the infiltrated zone. In the reaction zone and transition zone the resulting microstructure was composed of a metallic phase, graphite laminae and SiC particles. It was found that SiC decomposes into these areas because of the alloy Cu-Si, so the available Si forms a liquid solution that a room temperature consisted of a a solid solution and a {gamma} phase (Cu{sub 5}Si). The carbon resulting from the decomposition of SiC precipitated as graphite laminae. In addition, the SiC decomposition was decreasing as the initial amount of Si in the alloy increased. (Author) 37 refs.

  17. Calcium Carbonate

    Science.gov (United States)

    ... before being swallowed; do not swallow them whole. Drink a full glass of water after taking either the regular or chewable tablets or capsules. Some liquid forms of calcium carbonate must be shaken well before use.Do not ...

  18. Carbon Stars

    Indian Academy of Sciences (India)

    T. Lloyd Evans

    2010-12-01

    In this paper, the present state of knowledge of the carbon stars is discussed. Particular attention is given to issues of classification, evolution, variability, populations in our own and other galaxies, and circumstellar material.

  19. Materiales de Al2O3 - MgAl2O4 - CaAl12O19 - Ca2Mg2Al28O46 obtenidos mediante un proceso de sinterización reactiva entre Al2O3 y CaMg(CO3)2

    OpenAIRE

    Aza Moya, Antonio H. de; Peña, P.; Moset, M.

    2002-01-01

    [ES] Utilizado la información suministrada por el diagrama de equilibrio de fases Al2O3-MgO-CaO se ha diseñado y obtenido un material de Al2O3-MgAl2O4-CaAl12O19-Ca2Mg2Al28O46 mediante sinterización reactiva de una mezcla de Al2O3 y CaMg(CO3)2. Las reacciones que tienen lugar en la mezcla durante el proceso se han estudiado usando técnicas de análisis térmico diferencial, termogravimetrico y dilatometría. Muestras reaccionadas a temperaturas seleccionadas se han estudiado por difracci...

  20. Desarrollo de un Programa de Simulación de Procesos para el Tratamiento de Efluentes Líquidos Development of Simulation Program for Liquid Effluent Treatment

    Directory of Open Access Journals (Sweden)

    Z.M. Niño

    2004-01-01

    Full Text Available Se presenta el desarrollo de un programa para la simulación de procesos asociados al tratamiento de efluentes líquidos. El programa creado, denominado SIMTELUC, utiliza un enfoque modular secuencial para la administración y control del flujo de la información durante la simulación. Fueron desarrollados los siguientes módulos de cálculo: reactor biológico por lodos activados, filtro percolador, contactor biológico rotatorio o biodisco, sedimentador primario, unidad de floculación-coagulación, secador térmico, unidad de desinfección, adsorción sobre carbón activado, precipitación química, espesador de lodos, filtros, unidad por flotación con aire disuelto (DAF y API. Los módulos de cálculo desarrollados fueron validados comparando sus resultados con los obtenidos mediante un programa de simulacion comercial, presentando una desviación menor del 4%. A partir de los resultados obtenidos, se concluye que el programa desarrollado cumple con los objetivos propuestos, entregando buenos resultados, pudiendo ser extendido a la simulación de plantas de tratamiento existentes en la industriaThe objective of this research was to develop a software for the simulation of wastewater treatment processes. The software developed, named SIMTELUC, uses a modular and sequential approach for the management and control of the information flow during the process simulation. The following simulation units were developed: activated sludge reactor, trickling biofilters, rotary biological contactors, sedimentation basins, coagulation-flocculation basins, thermal dryer, chlorination units, activated carbon adsorption, chemical precipitation, sludge composting, filters, dissolved air flotation (DAF and API units. These units were validated, comparing their results with those obtained with a commercial simulation program, obtaining a deviation of less than 4%. It was concluded from the results obtained that the program developed meets the proposed

  1. Electrodos para supercondensadores obtenidos por electrodeposición

    OpenAIRE

    Aldama Amado, Iván

    2015-01-01

    Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Inorgánica. Fecha de lectura: 17-11-2015 Los supercondensadores son dispositivos de almacenamiento de energía que tienen alta densidad de potencia (hasta 10 kW/kg), tiempos cortos de carga y descarga (1-30 s) y alta ciclabilidad (1 000 000 de ciclos de carga/descarga). La principal desventaja es la baja densidad de energía (hasta 5 Wh/Kg), muy inferior a la densidad de ...

  2. Carbon classified?

    DEFF Research Database (Denmark)

    Lippert, Ingmar

    2012-01-01

    . Using an actor- network theory (ANT) framework, the aim is to investigate the actors who bring together the elements needed to classify their carbon emission sources and unpack the heterogeneous relations drawn on. Based on an ethnographic study of corporate agents of ecological modernisation over...... a period of 13 months, this paper provides an exploration of three cases of enacting classification. Drawing on ANT, we problematise the silencing of a range of possible modalities of consumption facts and point to the ontological ethics involved in such performances. In a context of global warming...

  3. Carbon Nanomembranes.

    Science.gov (United States)

    Turchanin, Andrey; Gölzhäuser, Armin

    2016-08-01

    Carbon nanomembranes (CNMs) are synthetic 2D carbon sheets with tailored physical or chemical properties. These depend on the structure, molecular composition, and surroundings on either side. Due to their molecular thickness, they can be regarded as "interfaces without bulk" separating regions of different gaseous, liquid, or solid components and controlling the materials exchange between them. Here, a universal scheme for the fabrication of 1 nm-thick, mechanically stable, functional CNMs is presented. CNMs can be further modified, for example perforated by ion bombardment or chemically functionalized by the binding of other molecules onto the surfaces. The underlying physical and chemical mechanisms are described, and examples are presented for the engineering of complex surface architectures, e.g., nanopatterns of proteins, fluorescent dyes, or polymer brushes. A simple transfer procedure allows CNMs to be placed on various support structures, which makes them available for diverse applications: supports for electron and X-ray microscopy, nanolithography, nanosieves, Janus nanomembranes, polymer carpets, complex layered structures, functionalization of graphene, novel nanoelectronic and nanomechanical devices. To close, the potential of CNMs in filtration and sensorics is discussed. Based on tests for the separation of gas molecules, it is argued that ballistic membranes may play a prominent role in future efforts of materials separation. PMID:27281234

  4. Trading forest carbon

    Science.gov (United States)

    The nature of carbon in forests is discussed from the perspective of carbon trading. Carbon inventories, specifically in the area of land use and forestry are reviewed for the Pacific Northwest. Carbon turnover in forests is discussed as it relates to carbon sequestration. Scient...

  5. Caracterización físico-mecánica, térmica y morfológica de polímeros de redes interpenetradas con base en poliuretano obtenido a partir de aceite de ricino y almidón modificados/polimetilmetacrilato (PMMA) Physico-mechanical, thermal and morphological Behaviour of simultaneous interpenetrating polymer networks based on polyurethane from modified castor oiland starch/poly(Methyl Methacrylate)

    OpenAIRE

    Manuel F. Valero; Jorge E. Pulido; Álvaro Ramírez; Diana C. Camargo; Daniel Navas

    2011-01-01

    El aceite de ricino se modificó por transesterificación con pentaeritritol. Paralelamente, se utilizó la reacción de glucosilación con glicerol para dividir el almidón en unidades monosacáridos. El glucósido obtenido reaccionó por transesterificación con el aceite modificado por transesterificación con pentaeritritol. Se determinó el índice de hidroxilo de los poliol-glucósidos en función del contenido de pentaeritritol y almidón utilizados en la síntesis. Se sintetizaron redes interpenetrada...

  6. Carbon Farming as a Carbon Negative Technology

    Science.gov (United States)

    Anderson, C.; Laird, D.; Hayes, D. J.

    2015-12-01

    Carbon farms have a pivotal role in national and international efforts to mitigate and adapt to climate change. A carbon farm in its broadest sense is one that reduces greenhouse gas (GHG) emissions or captures and holds carbon in vegetation and soils. Their capacity to remove carbon from the air and store it safely and permanently, while providing additional human and ecosystem benefits, means they could contribute significantly to national efforts to stabilize or reduce GHGs. We examine carbon farms in the context of corn and soybean production agriculture. We illustrate, using Iowa data but with relevance across United States corn and soybean production, the potential for carbon farms to reduce human GHG emissions and sequester carbon permanently at a rate that has meaningful impact on global greenhouse gas concentration. Carbon has been viewed as a next generation cash crop in Iowa for over a decade. The carbon farm perspective, however, goes beyond carbon as cash crop to make carbon the center of an entire farm enterprise. The transformation is possible through slight adjustment crop practices mixed with advances in technology to sequester carbon through biochar. We examine carbon balance of Iowa agriculture given only the combination of slight reduction in fertilizer and sequestration by biochar. We find the following. Iowa carbon farms could turn Iowa agriculture into a carbon sink. The estimated range of GHG reduction by statewide implementation of carbon farms is 19.46 to 90.27 MMt CO2-equivalent (CO2-e), while the current agricultural CO2-e emission estimate is 35.38 MMt CO2-e. Iowa carbon farm GHG reduction would exceed Iowa GHG reduction by wind energy (8.7 MMt CO2-e) and could exceed combined reductions from wind energy and corn grain ethanol (10.7 MMt CO2-e; 19.4 MMt CO2-e combined). In fact, Iowa carbon farms alone could exceed GHG reduction from national corn grain ethanol production (39.6 MMt CO2-e). A carbon price accessible to agricultural

  7. Net Ecosystem Carbon Flux

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Net Ecosystem Carbon Flux is defined as the year-over-year change in Total Ecosystem Carbon Stock, or the net rate of carbon exchange between an ecosystem and the...

  8. Carbon Monoxide (CO)

    Science.gov (United States)

    ... IAQ) » Carbon Monoxide's Impact on Indoor Air Quality Carbon Monoxide's Impact on Indoor Air Quality On this ... length of exposure. Top of Page Sources of Carbon Monoxide Sources of CO include: unvented kerosene and ...

  9. Carbon Monoxide Poisoning

    Science.gov (United States)

    ... Recommend on Facebook Tweet Share Compartir What is Carbon Monoxide? Carbon monoxide, or “CO,” is an odorless, colorless gas that can kill you. Carbon monoxide detector Where is CO found? CO is ...

  10. Integral Ring Carbon-Carbon Piston

    Science.gov (United States)

    Northam, G. Burton (Inventor)

    1999-01-01

    An improved structure for a reciprocating internal combustion engine or compressor piston fabricate from carbon-carbon composite materials is disclosed. An integral ring carbon-carbon composite piston, disclosed herein, reduces the need for piston rings and for small clearances by providing a small flexible, integral component around the piston that allows for variation in clearance due to manufacturing tolerances, distortion due to pressure and thermal loads, and variations in thermal expansion differences between the piston and cylinder liner.

  11. Carbon dioxide sequestration by mineral carbonation

    OpenAIRE

    Huijgen, W.J.J.

    2007-01-01

    The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept behind mineral CO2 sequestration is the mimicking of natural weathering processes in which calcium or magnesium containing minerals react with gaseous CO2 and form solid calcium or magnesium carbonate...

  12. Carbon Residence Times in Pedogenic Carbonate Pools

    Science.gov (United States)

    Monger, H.; Feng, Y.; Karnjanapiboonwang, A.

    2013-12-01

    Soil carbonate is a huge pool of terrestrial carbon that contains at least 930 to 940 Pg C and has influx rates on the order of 1 to 12 g CaCO3/m2/yr. Such large mass to flux ratios yield long mean residence times for carbon (e.g., 85,000 years)--assuming steady state. Like other global carbon pools, the soil carbonate pool has smaller sub-pools with higher influx rates and shorter mean residence times. For example, pedogenic carbonate in coppice dunes known to have formed since 1858 and carbonate formed on lithic artifacts in soils at archaeology sites suggests mean residence times can be as short as 120 years--again assuming steady state. Harder to assess are efflux rates as CO2 emissions or bicarbonate leaching. Some Bowen-ratio studies have nevertheless found evidence for CO2 emissions resulting from carbonate dissolution, and other studies have found evidence for bicarbonate leaching based on dissolution pipes through calcic horizons using soil morphology studies. Since an understanding of mean residence times are prerequisite for a better understanding of soil carbonate in the global carbon cycle, especially in a scenario of an expanding Aridosphere, more influx and efflux measurements are needed to evaluate the possibility of carbon sequestration by soil carbonate in hyperarid, arid, semiarid, or subhumid soils.

  13. Carbon dioxide sequestration by mineral carbonation

    NARCIS (Netherlands)

    Huijgen, W.J.J.

    2007-01-01

    The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept beh

  14. Caracterización físico-mecánica, térmica y morfológica de polímeros de redes interpenetradas con base en poliuretano obtenido a partir de aceite de ricino y almidón modificados/polimetilmetacrilato (PMMA

    Directory of Open Access Journals (Sweden)

    Manuel F. Valero

    2011-01-01

    Full Text Available El aceite de ricino se modificó por transesterificación con pentaeritritol. Paralelamente, se utilizó la reacción de glucosilación con glicerol para dividir el almidón en unidades monosacáridos. El glucósido obtenido reaccionó por transesterificación con el aceite modificado por transesterificación con pentaeritritol. Se determinó el índice de hidroxilo de los poliol-glucósidos en función del contenido de pentaeritritol y almidón utilizados en la síntesis. Se sintetizaron redes interpenetradas de polímero de manera simultánea (SINs con diferentes relaciones en peso poliuretano/PMMA de 100/0, 90/10, 80/20, 70/30, 60/40 y 50/50. Para la síntesis de la red de poliuretano (PU se utilizaron los poliol-glucósidos y diisocianato de isoforona (IPDI o con una relación NCO/OH = 1 y para la síntesis de la red de polimetilmetacrilato (PMMA se utilizó peróxido de benzoílo como agente iniciador y dimetacrilato de etilenglicol como agente entrecruzante. Los SINs se caracterizaron por sus propiedades fisicomecánicas como resistencia al ataque químico, dureza, resistencia a la tensión y elongación de ruptura. La estabilidad térmica de los SINs se determinó usando análisis termogravimétrico (TGA. La morfología de superficie se determinó usando microscopia electrónica de barrido (SEM y mostró una morfología de dos fases para todos los SINs.

  15. Ensayo de neutralización in vitro de aplicación en la evaluación de inmunógenos contra la hepatitis A, obtenidos mediante la tecnología de expresión en fagos filamentosos

    Directory of Open Access Journals (Sweden)

    Alicia Aguilar

    2010-04-01

    Full Text Available La inmunidad contra el virus de la hepatitis A (VHA se debe en primera instancia a la inducción de anticuerpos neutralizantes. Disponer de ensayos de neutralización es indispensable para evaluar nuevos candidatos vacunales contra este patógeno. En el presente trabajo se desarrolló un ensayo de neutralización in vitro que permitió evaluar la inmunogenicidad de mimotopos del VHA obtenidos mediante la tecnología de expresión en fagos al ser inmunizados ratones Balb/c. Diferentes diluciones de anticuerpos se incubaron con 103 o 102 Dosis Infecciosas en Cultivo de Tejidos 50% (DICT50 del clon citopático HM175/18f de VHA, y se inocularon en placas con células FRhK4. Después de 7 días de incubación el título neutralizante se determinó como el recíproco de la dilución del suero capaz de reducir la multiplicación viral al 50%. Tanto 103 como 102 DICT50 fueron neutralizadas por el anticuerpo monoclonal 7E7 y los sueros humanos (A12 y A31 positivos a anticuerpos anti-VHA. Los controles negativos del ensayo no neutralizaron al virus. Los títulos neutralizantes de los sueros de ratones inmunizados con fagos portadores de mimotopos de VHA oscilaron entre 4 y 16, mientras que los sueros preinmunes y los de ratones inmunizados con fago salvaje M13 no neutralizaron la infectividad viral. Este ensayo de neutralización resultó adecuado para la evaluación de los inmunógenos propuestos

  16. From carbon nanotubes to carbon atomic chains

    Science.gov (United States)

    Casillas García, Gilberto; Zhang, Weijia; José-Yacamán, Miguel

    2010-10-01

    Carbyne is a linear allotrope of carbon. It is formed by a linear arrangement of carbon atoms with sp-hybridization. We present a reliable and reproducible experiment to obtain these carbon atomic chains using few-layer-graphene (FLG) sheets and a HRTEM. First the FLG sheets were synthesized from worm-like exfoliated graphite and then drop-casted on a lacey-carbon copper grid. Once in the TEM, two holes are opened near each other in a FLG sheet by focusing the electron beam into a small spot. Due to the radiation, the carbon atoms rearrange themselves between the two holes and form carbon fibers. The beam is concentrated on the carbon fibers in order excite the atoms and induce a tension until multi wall carbon nanotube (MWCNT) is formed. As the radiation continues the MWCNT breaks down until there is only a single wall carbon nanotube (SWCNT). Then, when the SWCNT breaks, an atomic carbon chain is formed, lasts for several seconds under the radiation and finally breaks. This demonstrates the stability of this carbon structure.

  17. Carbon nanotube composite materials

    Energy Technology Data Exchange (ETDEWEB)

    O' Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  18. Mutagenicity of carbon nanomaterials

    DEFF Research Database (Denmark)

    Wallin, Håkan; Jacobsen, Nicklas Raun; White, Paul A;

    2011-01-01

    Carbon nanomaterials such carbon nanotubes, graphene and fullerenes are some the most promising nanomaterials. Although carbon nanomaterials have been reported to possess genotoxic potential, it is imperitive to analyse the data on the genotoxicity of carbon nanomaterials in vivo and in vitro...

  19. Electroanalysis with carbon paste electrodes

    CERN Document Server

    Svancara, Ivan; Walcarius, Alain; Vytras, Karel

    2011-01-01

    Introduction to Electrochemistry and Electroanalysis with Carbon Paste-Based ElectrodesHistorical Survey and GlossaryField in Publication Activities and LiteratureCarbon Pastes and Carbon Paste ElectrodesCarbon Paste as the Binary MixtureClassification of Carbon Pastes and Carbon Paste ElectrodesConstruction of Carbon Paste HoldersCarbon Paste as the Electrode MaterialPhysicochemical Properties of Carbon PastesElectrochemical Characteristics of Carbon PastesTesting of Unmodified CPEsIntera

  20. Mesoporous carbon materials

    Science.gov (United States)

    Dai, Sheng; Fulvio, Pasquale Fernando; Mayes, Richard T.; Wang, Xiqing; Sun, Xiao-Guang; Guo, Bingkun

    2014-09-09

    A conductive mesoporous carbon composite comprising conductive carbon nanoparticles contained within a mesoporous carbon matrix, wherein the conductive mesoporous carbon composite possesses at least a portion of mesopores having a pore size of at least 10 nm and up to 50 nm, and wherein the mesopores are either within the mesoporous carbon matrix, or are spacings delineated by surfaces of said conductive carbon nanoparticles when said conductive carbon nanoparticles are fused with each other, or both. Methods for producing the above-described composite, devices incorporating them (e.g., lithium batteries), and methods of using them, are also described.

  1. Pyrolyzed thin film carbon

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  2. Influencia del soporte sobre la actividad catalítica del paladio en la oxidación selectiva del etanol

    Directory of Open Access Journals (Sweden)

    Luis Carballo Suárez

    2011-01-01

    Full Text Available Aquí se reporta la comparación de los resultados obtenidos en cuanto a las diferencias en selectividades y conversiones de etanol hacia ácido acético y acetato de etilo, utilizando catalizadores de paladio metálico (0.5% en peso soportados en alfa-alúmina y carbón activado. Se pudo observar que el catalizador de paladio sobre alfa-alúmina presentó mayores conversiones del etanol alimentado hacia el ácido acético y por consiguiente mayor selectividad hacia éste producto, que el de paladio soportado sobre carbón activado, el cual mostró una mayor selectividad hacia el acetato de etilo.

  3. Adsorption of Carbon Dioxide on Activated Carbon

    Institute of Scientific and Technical Information of China (English)

    Bo Guo; Liping Chang; Kechang Xie

    2006-01-01

    The adsorption of CO2 on a raw activated carbon A and three modified activated carbon samples B, C, and D at temperatures ranging from 303 to 333 K and the thermodynamics of adsorption have been investigated using a vacuum adsorption apparatus in order to obtain more information about the effect of CO2 on removal of organic sulfur-containing compounds in industrial gases. The active ingredients impregnated in the carbon samples show significant influence on the adsorption for CO2 and its volumes adsorbed on modified carbon samples B, C, and D are all larger than that on the raw carbon sample A. On the other hand, the physical parameters such as surface area, pore volume, and micropore volume of carbon samples show no influence on the adsorbed amount of CO2. The Dubinin-Radushkevich (D-R) equation was the best model for fitting the adsorption data on carbon samples A and B, while the Freundlich equation was the best fit for the adsorption on carbon samples C and D. The isosteric heats of adsorption on carbon samples A, B, C, and D derived from the adsorption isotherms using the Clapeyron equation decreased slightly increasing surface loading. The heat of adsorption lay between 10.5 and 28.4 kJ/mol, with the carbon sample D having the highest value at all surface coverages that were studied. The observed entropy change associated with the adsorption for the carbon samples A, B, and C (above the surface coverage of 7 ml/g) was lower than the theoretical value for mobile adsorption. However, it was higher than the theoretical value for mobile adsorption but lower than the theoretical value for localized adsorption for carbon sample D.

  4. Accelerating Mineral Carbonation Using Carbonic Anhydrase.

    Science.gov (United States)

    Power, Ian M; Harrison, Anna L; Dipple, Gregory M

    2016-03-01

    Carbonic anhydrase (CA) enzymes have gained considerable attention for their potential use in carbon dioxide (CO2) capture technologies because they are able to catalyze rapidly the interconversion of aqueous CO2 and bicarbonate. However, there are challenges for widespread implementation including the need to develop mineralization process routes for permanent carbon storage. Mineral carbonation of highly reactive feedstocks may be limited by the supply rate of CO2. This rate limitation can be directly addressed by incorporating enzyme-catalyzed CO2 hydration. This study examined the effects of bovine carbonic anhydrase (BCA) and CO2-rich gas streams on the carbonation rate of brucite [Mg(OH)2], a highly reactive mineral. Alkaline brucite slurries were amended with BCA and supplied with 10% CO2 gas while aqueous chemistry and solids were monitored throughout the experiments (hours to days). In comparison to controls, brucite carbonation using BCA was accelerated by up to 240%. Nesquehonite [MgCO3·3H2O] precipitation limited the accumulation of hydrated CO2 species, apparently preventing BCA from catalyzing the dehydration reaction. Geochemical models reproduce observed reaction progress in all experiments, revealing a linear correlation between CO2 uptake and carbonation rate. Data demonstrates that carbonation in BCA-amended reactors remained limited by CO2 supply, implying further acceleration is possible. PMID:26829491

  5. Carbon fuel cells with carbon corrosion suppression

    Science.gov (United States)

    Cooper, John F.

    2012-04-10

    An electrochemical cell apparatus that can operate as either a fuel cell or a battery includes a cathode compartment, an anode compartment operatively connected to the cathode compartment, and a carbon fuel cell section connected to the anode compartment and the cathode compartment. An effusion plate is operatively positioned adjacent the anode compartment or the cathode compartment. The effusion plate allows passage of carbon dioxide. Carbon dioxide exhaust channels are operatively positioned in the electrochemical cell to direct the carbon dioxide from the electrochemical cell.

  6. Validade de indicadores de atividade física e sedentarismo obtidos por inquérito telefônico Validad de indicadores de actividad física y sedentarismo obtenidos por encuesta telefónica Validity of indicators of physical activity and sedentariness obtained by telephone survey

    Directory of Open Access Journals (Sweden)

    Carlos Augusto Monteiro

    2008-08-01

    controle das doenças crônicas não transmissíveis relacionadas ao sedentarismo.OBJETIVO: Evaluar la reproducibilidad y la validad de indicadores de actividad física y sedentarismo, obtenidos por sistema de vigilancia basado en encuestas telefónicas. MÉTODOS: Fueron realizadas análisis de reproducibilidad y validad en dos submuestras aleatorias (n=110 e n=111, respectivamente de la muestra total (N=2.024 de adultos (> 18 anos, estudiada por el sistema, en municipio de São Paulo (sudeste de Brasil, en 2005. Los indicadores evaluados incluyeron la frecuencia de "suficientemente activos en el ocio", "inactivos en cuatro dominios de la actividad física (ocio, trabajo, transporte y actividades domésticas" y "ver televisión por largos períodos". La reproducibilidad fue estudiada comparándose resultados obtenidos a partir de encuesta telefónica original del sistema y de otra encuesta idéntica repetida después de siete a quince días y hecha por entrevistador diferente del que hizo la encuesta original. La validad fue estudiada comparándose resultados obtenidos a partir de la encuesta telefónica original y de tres recordatorios de 24 horas (método de referencia realizados en la semana siguiente a la encuesta original. RESULTADOS: La frecuencia de los tres indicadores evaluados fue idéntica o muy próxima entre la primera y la segunda encuesta telefónica, y los coeficientes kappa se situaron entre 0,53 e 0,80, indicando buena reproducibilidad de todos los indicadores. Relativamente al método de referencia, se evidenció especificidad de 80% o más para los tres indicadores y sensibilidad de 69,7% para "ver televisión por largos períodos", 59,1% para "inactivos en cuatro dominios" y 50% para "suficientemente activos en el ocio". CONCLUSIONES: Los indicadores de actividad física y sedentarismo empleados por el sistema aparentan ser reproducibles y suficientemente determinados. Si mantenido en operación en los próximos anos, el sistema podrá ofrecer al

  7. Estudio del comportamiento mecánico de gelés físicos termorreversibles obtenidos a partir de copolímeros tribloques de PS-b-poli(etileno/butileno-PS en un disolvente selectivo del bloque central

    Directory of Open Access Journals (Sweden)

    Hernáez, E.

    2001-04-01

    a la de formación del gel los módulos elásticos obtenidos para los tres copolímeros son menores y la relajación es más rápida.

  8. Caracterización y comportamiento frente a la corrosión de recubrimientos de ácido fítico, obtenidos por conversión química, sobre substratos de magnesio en solución fisiológica

    Directory of Open Access Journals (Sweden)

    Hernández-Alvarado, Laura A.

    2014-06-01

    Full Text Available In order to improve the corrosion resistance of biodegradable magnesium and AZ31 magnesium alloy implants, a phytic acid coating has been applied on both substrates and their protective effect against corrosion has been assessed. The morphology and the chemical nature of the conversion coating were analyzed by SEM/EDX, XRD and FTIR. The spectra showed that the conversion coating was amorphous, and it was composed of Mg, O, and P on magnesium surface, along with Al, Zn and C on AZ31 alloy. The main coating components were chelate compounds formed by phytic acid and metallic ions. The corrosion resistance of bare and coated samples was evaluated by potentiodynamic polarization technique in Hank’s solution at 37 °C. The results indicate that phytic acid conversion coatings provided a very effective protection to the magnesium substrates studied.Con objeto de mejorar la resistencia a la corrosión de implantes biodegradables de magnesio y de la aleación AZ31, se ha depositado un recubrimiento de ácido fítico sobre ambos sustratos y se ha evaluado su efecto protector frente a la corrosión. El recubrimiento fue obtenido mediante un tratamiento de conversión química, por inmersión en una solución de ácido fítico al 0,5% a 60 °C. Distintas técnicas (MEB/EDX, XRD y FTIR fueron utilizadas para analizar la morfología del recubrimiento y su naturaleza química. Dichas técnicas mostraron que el recubrimiento de conversión era amorfo, con una composición química sobre la superficie de magnesio de Mg, O y P y, además, Al, Zn y C sobre la superficie de la aleación AZ31. Los componentes principales del recubrimiento fueron quelatos formados por ácido fítico e iones metálicos. La resistencia a la corrosión de muestras sin recubrir y recubiertas, se evaluó mediante polarización potenciodinámica en solución de Hank a 37 °C. Los resultados indican que los recubrimientos de conversión de ácido fítico proporcionan una protección muy

  9. Trading forest carbon - OSU

    Science.gov (United States)

    Issues associate with trading carbon sequestered in forests are discussed. Scientific uncertainties associated with carbon measurement are discussed with respect to proposed accounting procedures. Major issues include: (1) Establishing baselines. (2) Determining additivity from f...

  10. Soil Organic Carbon Stock

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Soil organic carbon (SOC) is the carbon held within soil organic constituents (i.e., products produced as dead plants and animals decompose and the soil microbial...

  11. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Education / Safety Education Centers En Español Carbon Monoxide Information Center The Invisible Killer Carbon monoxide, also known ... Install one and check its batteries regularly. View Information About CO Alarms Other CO Topics Safety Tips ...

  12. Biomass Carbon Stock

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Biomass carbon includes carbon stored in above- and below-ground live plant components (such as leaf, branch, stem and root) as well as in standing and down dead...

  13. Carbon Monoxide Safety

    Science.gov (United States)

    ... with the Media Fire Protection Technology Carbon monoxide safety outreach materials Help inform residents in your community ... KB | Spanish PDF 645 KB Handout: carbon monoxide safety Download this handout and add your organization's logo ...

  14. Calcium carbonate overdose

    Science.gov (United States)

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  15. Potassium carbonate poisoning

    Science.gov (United States)

    Potassium carbonate is a white powder used to make soap, glass, and other items. This article discusses poisoning from swallowing or breathing in potassium carbonate. This article is for information only. Do ...

  16. Carbon nanotube nanoelectrode arrays

    Science.gov (United States)

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  17. Metal filled porous carbon

    Science.gov (United States)

    Gross, Adam F.; Vajo, John J.; Cumberland, Robert W.; Liu, Ping; Salguero, Tina T.

    2011-03-22

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

  18. Protolytic carbon film technology

    Energy Technology Data Exchange (ETDEWEB)

    Renschler, C.L.; White, C.A.

    1996-04-01

    This paper presents a technique for the deposition of polyacrylonitrile (PAN) on virtually any surface allowing carbon film formation with only the caveat that the substrate must withstand carbonization temperatures of at least 600 degrees centigrade. The influence of processing conditions upon the structure and properties of the carbonized film is discussed. Electrical conductivity, microstructure, and morphology control are also described.

  19. Carbon nanotube quantum dots

    NARCIS (Netherlands)

    Sapmaz, S.

    2006-01-01

    Low temperature electron transport measurements on individual single wall carbon nanotubes are described in this thesis. Carbon nanotubes are small hollow cylinders made entirely out of carbon atoms. At low temperatures (below ~10 K) finite length nanotubes form quantum dots. Because of its small si

  20. Carbon Goes To…

    Science.gov (United States)

    Savasci, Funda

    2014-01-01

    The purposes of this activity are to help middle school students understand the carbon cycle and realize how human activities affect the carbon cycle. This activity consists of two parts. The first part of the activity focuses on the carbon cycle, especially before the Industrial Revolution, while the second part of the activity focuses on how…

  1. Carbon/Carbon Pistons for Internal Combustion Engines

    Science.gov (United States)

    Taylor, A. H.

    1986-01-01

    Carbon/carbon piston performs same function as aluminum pistons in reciprocating internal combustion engines while reducing weight and increasing mechanical and thermal efficiencies of engine. Carbon/carbon piston concept features low piston-to-cylinder wall clearance - so low piston rings and skirts unnecessary. Advantages possible by negligible coefficient of thermal expansion of carbon/carbon.

  2. Rapid determination of filamentous microorganisms in activated sludge; Determinacion rapida de microorganismos filamentosos en fangos activados

    Energy Technology Data Exchange (ETDEWEB)

    Arnaiz, C.; Jimenez, C.; Estevez, F. [Empresa Municipal de Abastecimiento y Saneamiento de Aguas de Sevilla (Spain)

    1999-07-01

    Despite many methods available biomass estimation of a bioprocess may sometimes become laborious and impracticable. Samples containing filamentous organisms, as in Wastewater Treatment Plants, present special counting difficulties. If they are abundant they may need to be estimated separately. In this work a counting method for these organisms is show. The main goal is to improve chlorination of activated sludge suffering bulking or foaming through a quantitative record of filamentous bacteria. (Author) 12 refs.

  3. Comportamiento mecánico a altas temperaturas de cementos de ceniza volante activados alcalinamente

    OpenAIRE

    Martin Sanz, Antonia; Fernandez Jimenez, Ana; Pastor Caño, Jose Ignacio; Palomo, Angel

    2010-01-01

    En este trabajo se realiza un estudio comparativo del comportamiento mecánico, en función de la temperatura, entre un cemento Portland comercial, utilizado de referencia y dos nuevos materiales cementantes. Los ensayos realizados se han centrado en muestras de cemento portland , muestras de cenizas volantes activadas con un 100% de silicato sódico y muestras con un 70% de ceniza y un 30% de cemento activadas con un activador en estado sólido.Se realizaron dos tipos de ensayos: 1) post tratami...

  4. Desarrollo de un Modelo Reológico de Lodos Activados Para Bioreactores Con Membrana (MBR)

    DEFF Research Database (Denmark)

    Ratkovich, Nicolas Rios; Bentzen, Thomas Ruby; Moreau, A.A.;

    2012-01-01

    Los bioreactores con membranas (MBR) han ganado cada vez más importancia en la última década para el tratamiento de aguas residuales [1] en comparación con los tratamientos convencionales. Entre sus causas cuentan su alta retención de sólidos, ocupación de menos espacio y la generación de una mej...

  5. Carbon-14 waste management

    International Nuclear Information System (INIS)

    Carbon-14 occurs in nature, but is also formed in nuclear reactors. Because of its long half-life and the biological significance of carbon, releases from nuclear facilities could have a significant radiological impact. Waste management strategies for carbon-14 are therefore of current concern. Carbon-14 is present in a variety of waste streams both at reactors and at reprocessing plants. A reliable picture of the production and release of carbon-14 from various reactor systems has been built up for the purposes of this study. A possible management strategy for carbon-14 might be the reduction of nitrogen impurity levels in core materials, since the activation of 14N is usually the dominant source of carbon-14. The key problem in carbon-14 management is its retention of off-gas streams, particularly in the dissolver off-gas stream at reprocessing plants. Three alternative trapping processes that convert carbon dioxide into insoluble carbonates have been suggested. The results show that none of the options considered need be rejected on the grounds of potential radiation doses to individuals. All exposures should be as low as reasonably achievable, economic and social factors being taken into account. If, on these grounds, retention and disposal of carbon-14 is found to be beneficial, then, subject to the limitations noted, appropriate retention, immobilization and disposal technologies have been identified

  6. Determinación de la actividad lignocelulolítica en sustrato natural de aislamientos fúngicos obtenidos de sabana de pastoreo y de bosque secundario de sabana inundable tropical Determination of lignocellulolytic activity in a natural substrate of native fungi strains obtained from savanna and of secondary forest from a tropical flooded savanna

    Directory of Open Access Journals (Sweden)

    Martha Lucía Ortiz Moreno

    2010-12-01

    Full Text Available El objetivo de este trabajo fue identificar aislamientos de hongos ligninolíticos y celulolíticos que pudieran degradar desechos de cosecha y mejorar las características del suelo en los Llanos Orientales, se realizó un muestreo siguiendo la metodología de transepto y muestras integradas. Se obtuvo una cepa ligninolítica (005L Verticillium spp. y 72 cepas celulolíticas. La comparación de los usos del suelo (sabana de pastoreo y bosque secundario mostró que no existía una relación entre el número de géneros obtenidos y las características del suelo. Posteriormente, se realizó la cuantificación de la actividad celulolítica y ligninolítica de los aislamientos para identificar las cepas que posteriormente serían evaluadas en el sustrato natural pasto seco (Brachiaria spp.. Se encontraron dos cepas con alta actividad exoglucanasa (055C y 061C Penicillium spp. y una cepa con alta actividad endoglucanasa (019C Trichoderma spp. respecto al control Trichoderma viride. En el sustrato natural se evaluaron los consorcios de las cepas seleccionadas formados por pares: una ligninolítica y una celulolítica. Las pruebas mostraron que los aislamientos promisorios aumentaron su actividad enzimática en el sustrato pasto superando a los controles positivos (Pleurotus ostreatus para lignina y T. viride para celulosa y que los consorcios no afectaron la capacidad enzimática de las cepas que los formaban. Por lo tanto, se recomienda utilizar estos consorcios para el desarrollo de biofertilizantes acondicionadores del suelo, empleando especialmente el consorcio formado por las cepas 005L (Verticillium spp. y 055C (Penicillium spp., que mostró alta actividad ligninolítica y celulolítica.The aim of this work was to identify lignolytic and cellulolytic fungal strains capable of degrading harvest waste and thereby improving the soil characteristics of the eastern Llanos of Colombia. Sampling was carried out using the transept methodology and

  7. Desarrollo de embriones de bovino obtenidos por fecundación in vitro cultivados con células oviductales o medio condicionado y transferidos a hembras receptoras Bovine embryo development produced by in vitro fertilization cultured with oviductal cell or conditioned medium and transfer to recipients

    Directory of Open Access Journals (Sweden)

    M RATTO

    1999-01-01

    Full Text Available Se comparó el desarrollo in vitro de ovocitos obtenidos de ovarios de vaca de matadero, madurados, fecundados y cultivados in vitro bajo dos sistemas. Los ovocitos fueron cultivados en un medio de maduración a 39 °C, 5 % de CO2 y humedad relativa de 95 % durante 22 horas. Posteriormente, fueron incubados con espermatozoides seleccionados a través de una gradiente discontinua de Percoll. La tasa de maduración nuclear y fecundación fueron de 93,7 % (74/79 y 76,9 % (50/65 respectivamente. Un total de 252 ovocitos fecundados fueron cultivados in vitro. El porcentaje de desarrollo in vitro a las 2 días post-inseminación (embriones de 4-8 células fue de 62,7 % (64/102 para los cigotos cultivados con células oviductales y de 67 % (100/150 para los cultivados en medio condicionado (P0,05. El porcentaje de desarrollo de mórulas fue de 17,6 % (18/102 para los cigotos cultivados con células oviductales y de 13,3 % (20/150 para los cultivados con medio condicionado (P0,05. Se obtuvo una tasa de desarrollo del 15,7 % (16/102 de blastocistos para aquellos cigotos cultivados con células oviductales. No se obtuvo blastocistos a partir de cigotos cultivados en medio condicionado. Cuatro blastocistos fueron transferidos a dos hembras receptoras. A los 42 y 57 días se encontró la presencia de un feto en cada hembraThe in vitro development of matured and fertilized bovine oocytes was compared between two culture systems. Oocytes were collected by aspiration of follicles of 3-8 mm in diameter using an 18g needle. After morphological selection the oocytes were incubated at 39 0C, 5 % C02 y 95 % relative humidity, during 22 hours. Afterwards, oocytes were incubated with spermatozoa selected by Percoll gradient system. The rate of nuclear maturation and fertilization was 93,7 % (74/79 and 76,9 % (50/65, respectively. A total of 252 zygotes were cultured, 102 with oviductal cells and 150 in conditioned medium. The in vitro development on day 2 of culture

  8. Carbon isotopes in mollusk shell carbonates

    Science.gov (United States)

    McConnaughey, Ted A.; Gillikin, David Paul

    2008-10-01

    Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod shell carbonates. Land snails construct their shells mainly from respired CO2, and shell δ13C reflects the local mix of C3 and C4 plants consumed. Shell δ13C is typically >10‰ heavier than diet, probably because respiratory gas exchange discards CO2, and retains the isotopically heavier HCO3 -. Respired CO2 contributes less to the shells of aquatic mollusks, because CO2/O2 ratios are usually higher in water than in air, leading to more replacement of respired CO2 by environmental CO2. Fluid exchange with the environment also brings additional dissolved inorganic carbon (DIC) into the calcification site. Shell δ13C is typically a few ‰ lower than ambient DIC, and often decreases with age. Shell δ13C retains clues about processes such as ecosystem metabolism and estuarine mixing. Ca2+ ATPase-based models of calcification physiology developed for corals and algae likely apply to mollusks, too, but lower pH and carbonic anhydrase at the calcification site probably suppress kinetic isotope effects. Carbon isotopes in biogenic carbonates are clearly complex, but cautious interpretation can provide a wealth of information, especially after vital effects are better understood.

  9. Carbon dioxide sensor

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Prabir K. (Worthington, OH); Lee, Inhee (Columbus, OH); Akbar, Sheikh A. (Hilliard, OH)

    2011-11-15

    The present invention generally relates to carbon dioxide (CO.sub.2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor that incorporates lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3). In another embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO.sub.2) sensors having lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3).

  10. Plumbing carbon nanotubes

    Science.gov (United States)

    Jin, Chuanhong; Suenaga, Kazu; Iijima, Sumio

    2008-01-01

    Since their discovery, the possibility of connecting carbon nanotubes together like water pipes has been an intriguing prospect for these hollow nanostructures. The serial joining of carbon nanotubes in a controlled manner offers a promising approach for the bottom-up engineering of nanotube structures-from simply increasing their aspect ratio to making integrated carbon nanotube devices. To date, however, there have been few reports of the joining of two different carbon nanotubes. Here we demonstrate that a Joule heating process, and associated electro-migration effects, can be used to connect two carbon nanotubes that have the same (or similar) diameters. More generally, with the assistance of a tungsten metal particle, this technique can be used to seamlessly join any two carbon nanotubes-regardless of their diameters-to form new nanotube structures.

  11. Nanographene reinforced carbon/carbon composites

    Science.gov (United States)

    Bansal, Dhruv

    Carbon/Carbon Composites (CCC) are made of carbon reinforcement in carbon matrix and have high thermal stability and fatigue resistance. CCC are used in nose cones, heat shields and disc brakes of aircrafts due to their exceptional mechanical properties at high temperature. The manufacturing process of CCC involves a carbonization stage in which unwanted elements, except carbon, are eliminated from the polymer precursor. Carbonization results in the formation of voids and cracks due to the thermal mismatch between the reinforcement and the matrix and expulsion of volatiles from the polymer matrix. Thermal cracks and voids decrease the density and mechanical properties of the manufactured CCC. In this work, Nanographene Platelets (NGP) were explored as nanofillers to fill the voids/cracks and reduce thermal shrinkage in CCC. They were first compared with Vapor Grown Carbon Nanofibers (VGCNF) by dispersion of different concentrations (0.5wt%, 1.5wt%, 3wt%) in resole-type phenolic resin and were characterized to explore their effect on rheology, heat of reaction and wetting behavior. The dispersions were then cured to form nanocomposites and were characterized for morphology, flexure and thermal properties. Finally, NGP were introduced into the carbon/carboncomposites in two stages, first by spraying in different concentrations (0.5wt%, 1.5wt%, 3wt%, 5wt %) during the prepreg formation and later during densification by directly mixing in the corresponding densification mix. The manufactured NGP reinforced CCC were characterized for microstructure, porosity, bulk density and mechanical properties (Flexure and ILSS) which were further cross-checked by non-destructive techniques (vibration and ultrasonic). In this study, it was further found that at low concentration (≤ 1.5 wt%) NGP were more effective in increasing the heat of reaction and in decreasing the viscosity of the phenolic resin. The decrease in viscosity led to better wetting properties of NGP / phenolic

  12. Physics of carbon nanostructures

    International Nuclear Information System (INIS)

    Carbon is a prominent element that appears in various structures with new promising technological applications. The physics of carbon nanostructures is one of the hot topics in modern condensed matter theory. I plan to present a brief introduction into the theory of variously shaped carbon nanostructures paying special attention to generic field-theory models. The preliminary plan is the following: (1) a brief historical excursus, (2) the most interesting experimental observations, (3) generic models for the description of electronic states in carbon nanoparticles (Dirac-type equations, defects, geometry, etc.), (4) open problems. (author)

  13. Carbon Monoxide Toxicity

    Science.gov (United States)

    Aniol, Michael J.

    1992-01-01

    Of all fatal poisonings in the United States, an estimated half are due to carbon monoxide. The number of non-lethal poisonings due to carbon monoxide is difficult to estimate because signs and symptoms of carbon monoxide poisoning cover a wide spectrum and mimic other disorders. Misdiagnosis is serious, as the patient often returns to the contaminated environment. Those not receiving proper treatment are at significant risk, as high as 10% to 12%, of developing late neurological sequelae. The diagnosis of carbon monoxide poisoning depends upon precise history taking, careful physical examination, and a high index of suspicion. ImagesFigure 2 PMID:21221282

  14. Nanoindentation of Carbon Nanostructures.

    Science.gov (United States)

    Kumar, Dinesh; Singh, Karamjit; Verma, Veena; Bhatti, H S

    2016-06-01

    In the present research paper carbon nanostructures viz. single walled carbon nanotubes, multi-walled carbon nanotubes, single walled carbon nanohorns and graphene nanoplatelets have been synthesized by CVD technique, hydrothermal method, DC arc discharge method in liquid nitrogen and microwave technique respectively. After synthesis 5 mm thick pallets of given nanomaterial are prepared by making a paste in isopropyl alcohol and using polyvinylidene difluoride as a binder and then these pallets were used for nanoindentation measurements. Hardness, reduced modulus, stiffness, contact height and contact area have been measured using nanoindenter. PMID:27427726

  15. Microbially mediated mineral carbonation

    Science.gov (United States)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  16. Novel carbon nanostructures

    International Nuclear Information System (INIS)

    The discovery of carbon nanotubes in 1991 opened up a challenging new area of research, because they are expected to be ideal building blocks for nanoscale applications due to their extraordinary mechanical and electronic properties. Various production methods have been developed, however precise control of nanotube morphology (e.g. length, diameter) has yet to be realised, a fact which has delayed industrial exploitation. Thus a comprehensive understanding of nanotube growth is essential, and this thesis is concerned with this important problem, i.e. the controlled production of novel carbon nanomaterials. Chapter 1 surveys production methods for fullerenes, carbon nanotubes and other carbon-based materials, such as fibres, particles etc. The sophisticated tools required for this work, e.g. high resolution transmission electron microscopy (HRTEM), high resolution electron energy loss spectroscopy (HREELS), etc. are reviewed in Chapter 2. Chapter 3 describes a novel approach to carbon nanotubes, using laser etching techniques, which generates aligned tubes of uniform diameter and length. The mode of catalyst preparation, as well as the nature of the precursor, play crucial roles in this process. The preparation of modified carbon nanotubes by the pyrolysis of metallocene, e.g. ferrocene in conjunction with various hydrocarbons, is discussed in Chapter 4. Superconducting interference device measurements (SQUID) show that Fe-filled carbon nanotubes exhibit enhanced coercivities in the 430-1070 Oe range, i.e. greater than those reported for Ni and Co nanowires. Carbon nanotubes can be also modified by replacing atoms of the carbon network with nitrogen, boron or both. The creation of large arrays of nitrogen-doped carbon nanotubes, for example CNx nanofibres, as well as the formation of BxCyNz onions is described in Chapter 5. Electron irradiation of these onions generates pure carbon onions. Finally (Chapter 6), the catalytic behaviour of metal particles in different

  17. Method for Making a Carbon-Carbon Cylinder Block

    Science.gov (United States)

    Ransone, Phillip O. (Inventor)

    1997-01-01

    A method for making a lightweight cylinder block composed of carbon-carbon is disclosed. The use of carbon-carbon over conventional materials. such as cast iron or aluminum, reduces the weight of the cylinder block and improves thermal efficiency of the internal combustion reciprocating engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall clearance can be small, especially when the carbon-carbon cylinder block is used in conjunction with a carbon-carbon piston. Use of the carbon-carbon cylinder block has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance.

  18. Fatores de risco para óbito neonatal obtidos pelo modelo de regressão multivariado de Cox Factores de riesgo para óbito neonatal obtenidos por el modelo de regresión multivariante de Cox Risk factors for neonatal death obtained by Cox multivariate regression analysis

    Directory of Open Access Journals (Sweden)

    Susana de Paula Risso

    2011-06-01

    Full Text Available OBJETIVO: Identificar os fatores associados ao óbito neonatal em São José dos Campos (SP. MÉTODOS: Estudo epidemiológico do tipo longitudinal para o qual foi construído um banco de dados com informações do recém-nascido e da mãe obtidas a partir das Declarações de Nascido Vivo e de Óbito de neonatos de mães residentes em São José dos Campos, nos anos de 2003 e 2004. Definiu-se como variável dependente o óbito até o 28º dia após o nascimento. A análise multivariada, utilizando o modelo de Cox, foi aplicada para verificar a associação entre o óbito neonatal e as seguintes variáveis independentes: sexo, peso ao nascer, duração da gestação, Apgar no 1º e 5º minuto, idade materna, nível de instrução da mãe, número de óbitos fetais e de filhos vivos prévio, tipo de parto e gestação única ou múltipla. O nível de significância adotado foi pOBJETIVO: Identificar los factores asociados al óbito neonatal en São José dos Campos. MÉTODOS: Se trata de estudio epistemológico de tipo longi-tudinal para el que se construyó una base de datos con informa-ciones del recién-nacido y de la madre, obtenidos a partir de las Declaraciones de Nacido Vivo y de óbito de neonatos y de madres residentes en São José dos Campos (São Paulo, Brasil, en los años de 2003 y 2004. Se definió como variable dependiente el óbito hasta el 28º día después del nacimiento. El análisis multivaria-do, utilizando el modelo de Cox, fue aplicado para verificar la asociación entre el óbito neonatal y las siguientes variables inde-pendientes: sexo, peso al nacer, duración de la gestación, Apgar en el 1er y 3er minuto, edad materna, nivel de instrucción de la madre, número de óbitos fetales y de hijos vivos previo, tipo de parto y gestación única o múltiple. El nivel de significancia adoptado fue pOBJECTIVE: To identify the risk factors for neonatal death in São José dos Campos (SP Brazil. METHODS: This longitudinal study

  19. Grado de acuerdo entre los índices adiposo-musculares obtenidos a partir de medidas antropométricas del brazo, pliegues cutáneos e impedancia bioeléctrica Interchangeability of the fat-to-fat-free mass ratios obtained by arm anthropometric measures, skinfold thickness and bioelectrical impedance

    Directory of Open Access Journals (Sweden)

    V. Martín Moreno

    2003-04-01

    Full Text Available Objetivo: La masa grasa, la masa libre de grasa y la relación entre ambas, el índice adiposo-muscular, son parámetros útiles para valorar clínicamente al paciente. El objetivo de este estudio es medir el grado de acuerdo entre los índices adiposo-musculares corporales (IAMC obtenidos mediante los pliegues cutáneos con la ecuación de Siri para cuatro pliegues (IAMC Siri y para el pliegue del tríceps (IAMCtríceps; por bioimpedanciometría (IAMC Omron; y mediante las áreas adiposa y muscular del brazo (IAM, valorando su intercambiabilidad. Intervenciones: Estudio descriptivo transversal. Se valoró mediante antropometría e impedancia bioeléctrica (Omron BF 300® a 145 personas, analizándose la concordancia entre métodos mediante el coeficiente de correlación intraclase (CCI y el método de Bland-Altman. El método de referencia fue IAMC Siri. Resultados: El CCI entre IAMC Siri e IAMCtríceps fue de 0,9304 (0,9035; 0,9498, entre IAMC Siri e IAMC Omron de 0,9114 (0,8771; 0,9361 y entre IAMC Siri e IAM de 0,7726 (0,6846; 0,8361. Con el método de Bland-Altman IAMC Siri e IAMCtríceps (- 0,171; 0,117 presentan el intervalo de concordancia más estrecho, seguido de IAMC Siri - IAMC Omron (- 0,186; 0,178. Los límites del intervalo entre IAM e IAMC Siri (- 0,2; 0,42, IAMCtríceps (- 0,26; 0,42 o IAMC Omron (- 0,292; 0,504 superaron el punto de corte (- 0,2; 0,2. Conclusiones: IAMCtríceps e IAMC Omron son intercambiables entre sí y con IAMC Siri, pero IAM no es intercambiable con IAMC Siri, IAMCtríceps o IAMC Omron, resultado que sugiere que el IAM puede no reflejar adecuadamente la composición corporal. IAMCtríceps e IAMC Omron son alternativas válidas a IAMC Siri en la valoración del índice adiposo-muscular.Background: Body fat, fat free mass and the relationship between both, the fat-to-fat-free mass ratio are useful parameters in the nutritional evaluation of the patient. The aim of this study is to evaluate the degree of

  20. Aislamiento e identificación de pestivirus obtenidos de alpacas (Lama pacos y llamas (Lama glama de la Región Metropolitana, Chile Isolation and identification of pestiviruses in alpacas (Lama pacos and llamas (Lama glama introduced to the Región Metropolitana, Chile

    Directory of Open Access Journals (Sweden)

    M O Celedón

    2006-01-01

    Full Text Available El ambiente natural para más del 90% de las alpacas (Lama pacos y llamas (Lama glama, camélidos sudamericanos (CSA domésticos de Chile, se ubica entre los 11° y 21° latitud sur a 3.800 y 5.000 m de altitud. En el último tiempo las alpacas y las llamas han sido introducidas en otros lugares geográficos del país, donde toman contacto con rumiantes domésticos, facilitándose la infección con el virus diarrea viral bovina (VDVB que está presente en bovinos, ovinos y caprinos de Chile. El VDVB incluye a dos especies, VDVB genotipo I y VDVB genotipo II, que junto con el virus de la enfermedad de la frontera (VEF y el virus de la peste porcina clásica (PPC conforman el género Pestivirus de la familia Flaviviridae. Este estudio evalúa la hipótesis que los CSA introducidos en la Región Metropolitana (R.M. de Chile están infectados con pestivirus. Para hacer el aislamiento viral se tomaron muestras de 80 CSA de la RM, 42 alpacas y 35 llamas vivas, 2 llamas muertas y un feto abortado provenientes de 4 rebaños sospechosos de estar infectados con pestivirus. Las muestras fueron inoculadas en cultivos celulares primarios de pulmón fetal bovino (libre de VDVB, subcultivando por 5 veces cada muestra. Para detectar antígenos de pestivirus, las células con las muestras fueron analizadas por prueba de inmunofluorescencia directa y de inmunoperoxidasa indirecta. Para la caracterización molecular, una fracción del fragmento no traducido del genoma viral (5’UTR de los aislados fue amplificado por RT-PCR y posteriormente, para identificar las especies virales, fue tratado con las enzimas de restricción Bgl I, Pst I y Xho I. Los resultados muestran que 18 CSA, 10 de alpacas y 8 de llamas de los 4 rebaños estudiados estaban infectadas con pestivirus. Todos los aislados fueron no citopáticos. En 6 alpacas se aisló VDVB I y en 4 alpacas y 8 llamas se aisló VDVB II. El virus fue obtenido desde 8 alpacas sanas, 2 alpacas con aborto, 5 llamas

  1. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Consumers Businesses Contact CPSC Website Design Feedback Consumers: Español Businesses: Español , 中文 , Tiếng Việt Connect with Us : Twitter YouTube ... Safely Home / Safety Education / Safety Education Centers En Español Carbon Monoxide Information Center The Invisible Killer Carbon ...

  2. Carbon black recovery

    International Nuclear Information System (INIS)

    A process and apparatus for recovering carbon black from hot smoke which comprises passing the smoke through a cyclone separation zone following cooling, then through aggregate filter beds and regeneration of filter beds with clean off-gas which is recycled to the carbon black reaction zone as quench

  3. Carbon for sensing devices

    CERN Document Server

    Tagliaferro, Alberto

    2015-01-01

    This book reveals why carbon is playing such an increasingly prominent role as a sensing material. The various steps that transform a raw material in a sensing device are thoroughly presented and critically discussed.  The authors deal with all aspects of carbon-based sensors, starting from the various hybridization and allotropes of carbon, with specific focus on micro and nanosized carbons (e.g., carbon nanotubes, graphene) and their growth processes. The discussion then moves to the role of functionalization and the different routes to achieve it. Finally, a number of sensing applications in various fields are presented, highlighting the connection with the basic properties of the various carbon allotropes.  Readers will benefit from this book’s bottom-up approach, which starts from the local bonding in carbon solids and ends with sensing applications, linking the local hybridization of carbon atoms and its modification by functionalization to specific device performance. This book is a must-have in th...

  4. Fly ash carbon passivation

    Science.gov (United States)

    La Count, Robert B; Baltrus, John P; Kern, Douglas G

    2013-05-14

    A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

  5. Carbon Capture and Storage

    NARCIS (Netherlands)

    Benson, S.M.; Bennaceur, K.; Cook, P.; Davison, J.; Coninck, H. de; Farhat, K.; Ramirez, C.A.; Simbeck, D.; Surles, T.; Verma, P.; Wright, I.

    2012-01-01

    Emissions of carbon dioxide, the most important long-lived anthropogenic greenhouse gas, can be reduced by Carbon Capture and Storage (CCS). CCS involves the integration of four elements: CO 2 capture, compression of the CO2 from a gas to a liquid or a denser gas, transportation of pressurized CO 2

  6. COMMITTED TO CARBON REDUCTION

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Chinese efforts to lower carbon emissions through environmentally friendly means begin gaining momentum Efforts to curb carbon emissions continue to take shape as China adheres to its pledge for a brighter, greener future. More importantly, as environmental measures take hold and develop

  7. Amorphous iron (II) carbonate

    DEFF Research Database (Denmark)

    Sel, Ozlem; Radha, A.V.; Dideriksen, Knud;

    2012-01-01

    Abstract The synthesis, characterization and crystallization energetics of amorphous iron (II) carbonate (AFC) are reported. AFC may form as a precursor for siderite (FeCO3). The enthalpy of crystallization (DHcrys) of AFC is similar to that of amorphous magnesium carbonate (AMC) and more...

  8. Carbon Dioxide Fountain

    Science.gov (United States)

    Kang, Seong-Joo; Ryu, Eun-Hee

    2007-01-01

    This article presents the development of a carbon dioxide fountain. The advantages of the carbon dioxide fountain are that it is odorless and uses consumer chemicals. This experiment also is a nice visual experiment that allows students to see evidence of a gaseous reagent being consumed when a pressure sensor is available. (Contains 3 figures.)…

  9. Carbon dioxide recycling

    Science.gov (United States)

    The recycling of carbon dioxide to methanol and dimethyl ether is seen to offer a substantial route to renewable and environmentally carbon neutral fuels. One of the authors has championed the “Methanol Economy" in articles and a book. By recycling ambient CO2, the authors argue ...

  10. De-carbonizingChina

    Institute of Scientific and Technical Information of China (English)

    zhou; Xiaoyan

    2013-01-01

    Innovation in the energy sector will pave the way for the country’slow-carbon future Although its per-capita emission is roughly on par with the world’s average, China is the world’s largest carbon dioxide emitter,

  11. Major carbon industries in India

    Energy Technology Data Exchange (ETDEWEB)

    Jain, P.K.

    1982-01-01

    The history of the major carbon industries in India, their growth, present status, problems and future prospects are described. Chapters cover: raw petroleum coke, calcined petroleum coke, graphite electrodes and anodes, carbon electrode paste, calcined anthracite coal, low-ash metallurgical coke, carbon black industry, activated carbon, midget electrodes, cinema arc carbons, carbon blocks and brushes for electrical machinery, and the growth of the aluminium industry and its impact on the calcined petroleum coke industry.

  12. Synthesis of hydrated lutetium carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Song Liu [South China Univ. of Technology, Dept. of Applied Chemistry, Guangdong (China); Rong-jun Ma [Changsha Research Institute of Minig and Metallurgy, Hunan (China)

    1997-09-01

    Crystalline lutetium carbonate was synthesized for the corresponding chloride using ammonium bicarbonate as precipitant. The chemical analyses suggest that the synthesized lutetium carbonate is a hydrated basic carbonate or oxycarbonate. The X-ray powder diffraction data are presented. The IR data for the compound show the presence of two different carbonate groups. There is no stable intermediate carbonate in the process of thermal decomposition of the lutetium carbonate. (au) 15 refs.

  13. Conducting carbonized polyaniline nanotubes

    Science.gov (United States)

    Mentus, Slavko; Ćirić-Marjanović, Gordana; Trchová, Miroslava; Stejskal, Jaroslav

    2009-06-01

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 °C min-1 up to a maximum temperature of 800 °C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 µm, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 µm, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm-1, increased to 0.7 S cm-1 upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  14. Conducting carbonized polyaniline nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Mentus, Slavko; Ciric-Marjanovic, Gordana [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Trchova, Miroslava; Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Square 2, 162 06 Prague 6 (Czech Republic)], E-mail: gordana@ffh.bg.ac.rs

    2009-06-17

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min{sup -1} up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 {mu}m, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 {mu}m, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm{sup -1}, increased to 0.7 S cm{sup -1} upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  15. Small diameter carbon nanopipettes

    Science.gov (United States)

    Singhal, Riju; Bhattacharyya, Sayan; Orynbayeva, Zulfiya; Vitol, Elina; Friedman, Gary; Gogotsi, Yury

    2010-01-01

    Nanoscale multifunctional carbon probes facilitate cellular studies due to their small size, which makes it possible to interrogate organelles within living cells in a minimally invasive fashion. However, connecting nanotubes to macroscopic devices and constructing an integrated system for the purpose of fluid and electrical signal transfer is challenging, as is often the case with nanoscale components. We describe a non-catalytic chemical vapor deposition based method for batch fabrication of integrated multifunctional carbon nanopipettes (CNPs) with tip diameters much smaller (10-30 nm) than previously reported (200 nm and above) and approaching those observed for multiwalled carbon nanotubes. This eliminates the need for complicated attachment/assembly of nanotubes into nanofluidic devices. Variable tip geometries and structures were obtained by controlled deposition of carbon inside and outside quartz pipettes. We have shown that the capillary length and gas flow rate have a marked effect on the carbon deposition. This gives us a flexible protocol, useful for growing carbon layers of different thicknesses at selective locations on a glass pipette to yield a large variety of cellular probes in bulk quantities. The CNPs possess an open channel for fluid transfer with the carbon deposited inside at 875 °C behaving like an amorphous semiconductor. Vacuum annealing of the CNP tips at temperatures up to 2000 °C yields graphitic carbon structures with an increase in conductivity of two orders of magnitude. Penetration of the integrated carbon nanoprobes into cells was shown to produce minimal Ca2+ signals, fast recovery of basal Ca2+ levels and no adverse activation of the cellular metabolism during interrogation times as long as 0.5-1 h.

  16. Small diameter carbon nanopipettes

    International Nuclear Information System (INIS)

    Nanoscale multifunctional carbon probes facilitate cellular studies due to their small size, which makes it possible to interrogate organelles within living cells in a minimally invasive fashion. However, connecting nanotubes to macroscopic devices and constructing an integrated system for the purpose of fluid and electrical signal transfer is challenging, as is often the case with nanoscale components. We describe a non-catalytic chemical vapor deposition based method for batch fabrication of integrated multifunctional carbon nanopipettes (CNPs) with tip diameters much smaller (10-30 nm) than previously reported (200 nm and above) and approaching those observed for multiwalled carbon nanotubes. This eliminates the need for complicated attachment/assembly of nanotubes into nanofluidic devices. Variable tip geometries and structures were obtained by controlled deposition of carbon inside and outside quartz pipettes. We have shown that the capillary length and gas flow rate have a marked effect on the carbon deposition. This gives us a flexible protocol, useful for growing carbon layers of different thicknesses at selective locations on a glass pipette to yield a large variety of cellular probes in bulk quantities. The CNPs possess an open channel for fluid transfer with the carbon deposited inside at 875 deg. C behaving like an amorphous semiconductor. Vacuum annealing of the CNP tips at temperatures up to 2000 deg. C yields graphitic carbon structures with an increase in conductivity of two orders of magnitude. Penetration of the integrated carbon nanoprobes into cells was shown to produce minimal Ca2+ signals, fast recovery of basal Ca2+ levels and no adverse activation of the cellular metabolism during interrogation times as long as 0.5-1 h.

  17. Carbon Ion Therapy

    DEFF Research Database (Denmark)

    Bassler, Niels; Hansen, David Christoffer; Herrmann, Rochus;

    On the importance of choice of target size for selective boosting of hypoxic tumor subvolumina in carbon ion therapy Purpose: Functional imaging methods in radiotherapy are maturing and can to some extent uncover radio resistant structures found within a tumour entity. Selective boost of identified...... effect. All cell lines investigated here did not reach an OER of 1, even for the smaller structures, which may indicate that the achievable dose average LET of carbon ions is too low, and heavier ions than carbon may be considered for functional LET-painting....

  18. 46 CFR 151.50-41 - Carbon disulfide (carbon bisulfide).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Carbon disulfide (carbon bisulfide). 151.50-41 Section... CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-41 Carbon disulfide (carbon bisulfide). (a) All openings shall be in the top of the tank. (b) Loading lines...

  19. Carbon Stock and Carbon Cycle of Wetland Ecosystem

    Institute of Scientific and Technical Information of China (English)

    Zhangquan; ZENG; Canming; ZHANG; Jiao; LI; Nan; YANG; Xihao; LI; Yandong; NIU; Zijian; WU

    2014-01-01

    Wetland ecosystem is an essential ecosystem in the world. Its organic carbon stock and carbon cycle are important basis of global carbon cycle researches and also major contents of global climate change researches. Researches have shown that wetland protection and restoration can promote carbon accumulation and reduce emission of greenhouse gases. This paper discussed influence of carbon stock and carbon balance of wetland ecosystem and emission of greenhouse gases,as well as the relationship between wetland and global climate changes. Finally,it made prospect on researches about carbon cycle of Dongting Lake.

  20. A novel carbon fiber based porous carbon monolith

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, T.D.; Klett, J.W.; Weaver, C.E.

    1995-06-01

    A novel porous carbon material based on carbon fibers has been developed. The material, when activated, develops a significant micro- or mesopore volume dependent upon the carbon fiber type utilized (isotropic pitch or polyacrylonitrile). The materials will find applications in the field of fluid separations or as a catalyst support. Here, the manufacture and characterization of our porous carbon monoliths are described. A novel adsorbent carbon composite material has been developed comprising carbon fibers and a binder. The material, called carbon fiber composite molecular sieve (CFCMS), was developed through a joint research program between Oak Ridge National Laboratory (ORNL) and the University of Kentucky, Center for Applied Energy Research (UKCAER).

  1. Authigenic Carbonate and the History of the Global Carbon Cycle

    Science.gov (United States)

    Schrag, Daniel P.; Higgins, John. A.; Macdonald, Francis A.; Johnston, David T.

    2013-02-01

    We present a framework for interpreting the carbon isotopic composition of sedimentary rocks, which in turn requires a fundamental reinterpretation of the carbon cycle and redox budgets over Earth's history. We propose that authigenic carbonate, produced in sediment pore fluids during early diagenesis, has played a major role in the carbon cycle in the past. This sink constitutes a minor component of the carbon isotope mass balance under the modern, high levels of atmospheric oxygen but was much larger in times of low atmospheric O2 or widespread marine anoxia. Waxing and waning of a global authigenic carbonate sink helps to explain extreme carbon isotope variations in the Proterozoic, Paleozoic, and Triassic.

  2. High performance carbon-carbon composites

    Indian Academy of Sciences (India)

    Lalit M Manocha

    2003-02-01

    Carbon-carbon composites rank first among ceramic composite materials with a spectrum of properties and applications in various sectors. These composites are made of fibres in various directions and carbonaceous polymers and hydrocarbons as matrix precursors. Their density and properties depend on the type and volume fraction of reinforcement, matrix precursor used and end heat treatment temperature. Composites made with thermosetting resins as matrix precursors possess low densities (1.55–1.75 g/cm3) and well-distributed microporosity whereas those made with pitch as the matrix precursor, after densification exhibit densities of 1.8–2.0 g/cm3 with some mesopores, and those made by the CVD technique with hydrocarbon gases, possess intermediate densities and matrices with close porosities. The former (resin-based) composites exhibit high flexural strength, low toughness and low thermal conductivity, whereas the latter (pitch- and CVD-based) can be made with very high thermal conductivity (400–700 W/MK) in the fibre direction. Carbon-carbon composites are used in a variety of sectors requiring high mechanical properties at elevated temperatures, good frictional properties for brake pads in high speed vehicles or high thermal conductivity for thermal management applications. However, for extended life applications, these composites need to be protected against oxidation either through matrix modification with Si, Zr, Hf etc. or by multilayer oxidation protection coatings consisting of SiC, silica, zircon etc.

  3. Carbon aerogels; Les aerogels de carbone

    Energy Technology Data Exchange (ETDEWEB)

    Berthon-Fabry, S.; Achard, P

    2003-06-15

    The carbon aerogel is a nano-porous material at open porosity, electrical conductor. The aerogels morphology is variable in function of the different synthesis parameters. This characteristic offers to the aerogels a better adaptability to many applications: electrodes (super condensers, fuel cells). The author presents the materials elaboration and their applications. It provides also the research programs: fundamental research, realization of super-condenser electrodes, fuel cells electrodes, gas storage materials and opaque materials for thermal insulation. (A.L.B.)

  4. Sodium carbonate poisoning

    Science.gov (United States)

    Sodium carbonate is found in: Automatic dishwashing soaps Clinitest (diabetes testing) tablets Glass products Pulp and paper products Some bleaches Some bubble bath solutions Some steam iron cleaners Note: This list is not all-inclusive.

  5. Carbon monoxide poisoning

    Science.gov (United States)

    ... heater). Many carbon monoxide poisonings occur in the winter months when furnaces, gas fireplaces, and portable heaters ... 16567227 www.ncbi.nlm.nih.gov/pubmed/16567227 . Nelson LS, Hoffman RS. Inhaled toxins. In: Marx JA, ...

  6. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... United States die every year from accidental non-fire related CO poisoning. Products that can produce deadly ... Driven Generators, 2004-2014 January 07, 2016 Non-Fire Carbon Monoxide Deaths Associated with the Use of ...

  7. FLUIDIZATION OF CARBON NANOTUBES

    Institute of Scientific and Technical Information of China (English)

    Fei Wei; Cang Huang; Yao Wang

    2005-01-01

    Carbon nanotubes (CNTs) can be fluidized in the form of fluidlike agglomerates made of many three-dimensional sub-agglomerates, having a multi-stage agglomerate (MSA) structure and containing large amounts of twisting CNTs of micrometer magnitude.

  8. Carbon nanotubes: Fibrillar pharmacology

    Science.gov (United States)

    Kostarelos, Kostas

    2010-10-01

    The mechanisms by which chemically functionalized carbon nanotubes flow in blood and are excreted through the kidneys illustrate the unconventional behaviour of these fibrillar nanostructures, and the opportunities they offer as components for the design of advanced delivery vehicles.

  9. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Safety More CO Blogs Research & Statistics March 09, 2016 Supplemental Memos Regarding Some of the Hazards Associated with Engine-Driven Generators, 2004-2014 January 07, 2016 Non-Fire Carbon Monoxide Deaths Associated with the ...

  10. The Carbon Emission Game

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    When Chinese President Hu Jintao attended the UN climate summit on September22,he made a solemn commitment that China will cut its per GDP unit carbon emission to a significant amount in 2020 compared with that of 2005.

  11. Total Ecosystem Carbon Stock

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Total ecosystem carbon includes above- and below-ground live plant components (such as leaf, branch, stem and root), dead biomass (such as standing dead wood, down...

  12. Carbon monoxide intoxication

    Energy Technology Data Exchange (ETDEWEB)

    Kales, S.N. (Cambridge Hospital, MA (United States))

    1993-11-01

    Carbon monoxide poisoning usually results from inhalation of exhaust fumes from motor vehicles, smoke from fires or fumes from faulty heating systems. Carbon monoxide has a high affinity for hemoglobin, with which it forms carboxyhemoglobin. The resulting decrease in both oxygen-carrying capacity and oxygen release can lead to end-organ hypoxia. The clinical presentation is nonspecific. Headache, dizziness, fatigue and nausea are common in mild to moderate carbon monoxide poisoning. In more severe cases, tachycardia, tachypnea and central nervous system depression occur. When carbon monoxide intoxication is suspected, empiric treatment with 100 percent oxygen should be initiated immediately. The diagnosis is confirmed by documenting an elevated carboxyhemoglobin level. Hyperbaric oxygen therapy is recommended in patients with neurologic dysfunction, cardiac dysfunction or a history of unconsciousness. 26 refs.

  13. Carbon partitioning in photosynthesis.

    Science.gov (United States)

    Melis, Anastasios

    2013-06-01

    The work seeks to raise awareness of a fundamental problem that impacts the renewable generation of fuels and chemicals via (photo)synthetic biology. At issue is regulation of the endogenous cellular carbon partitioning between different biosynthetic pathways, over which the living cell exerts stringent control. The regulation of carbon partitioning in photosynthesis is not understood. In plants, microalgae and cyanobacteria, methods need be devised to alter photosynthetic carbon partitioning between the sugar, terpenoid, and fatty acid biosynthetic pathways, to lower the prevalence of sugar biosynthesis and correspondingly upregulate terpenoid and fatty acid hydrocarbons production in the cell. Insight from unusual but naturally occurring carbon-partitioning processes can help in the design of blueprints for improved photosynthetic fuels and chemicals production.

  14. Carbon and oxygen isotope microanalysis of carbonate.

    Science.gov (United States)

    Velivetskaya, Tatiana A; Ignatiev, Alexander V; Gorbarenko, Sergey A

    2009-08-30

    Technical modification of the conventional method for the delta(13)C and delta(18)O analysis of 10-30 microg carbonate samples is described. The CO(2) extraction is carried out in vacuum using 105% phosphoric acid at 95 degrees C, and the isotopic composition of CO(2) is measured in a helium flow by gas chromatography/isotope ratio mass spectrometry (GC/IRMS). The feed-motion of samples to the reaction vessel provides sequential dropping of only the samples (without the sample holder) into the acid, preventing the contamination of acid and allowing us to use the same acid to carry out very large numbers of analyses. The high accuracy and high reproducibility of the delta(13)C and delta(18)O analyses were demonstrated by measurements of international standards and comparison of results obtained by our method and by the conventional method. Our method allows us to analyze 10 microg of the carbonate with a standard deviation of +/-0.05 per thousand for delta(13)C and delta(18)O. The method has been used successfully for the analyses of the oxygen and carbon isotopic composition of the planktonic and benthic foraminifera in detailed palaeotemperature reconstructions of the Okhotsk Sea. PMID:19603476

  15. Modelo de exploración para estimación rápida del Poder Calorífico Superior de racimos vacíos del fruto de palma de aceite basado en el contenido de Cenizas obtenido a partir de datos de análisis próximo

    Directory of Open Access Journals (Sweden)

    Jorge Villegas

    2014-07-01

    Full Text Available A correlation model for a quick-scan estimation of the Higher Heating Value (HHV of Oil Palm Empty Fruit Bunches (EFB base on proximate analysis is presented in this paper. The proximate analysis variables Fixed Carbon (FC, Ash Content (Ash, Volatile Matter (VM, Residual Moisture were analyzed statistically to obtain a model to estimate HHV which can be used as a support for evaluating the energetic disponibility of the EFB,  with Ash content as the input variable.  The samples were taken directly from the end of the processing line (the process exit after the fruit removal section in facilities of agro-industrial companies located in the Colombian coast. The average HHV obtained was 16.18 MJ/kg, and the minimum and maximum value of HHV was 13.6 MJ/kg and 19.51 MJ/kg, respectively.

  16. States and carbon

    International Nuclear Information System (INIS)

    The climate challenge appeals to an unprecedented mutation of our societies. From north to south, all our life styles will have to be changed from dwelling, to transport and feeding. These changes will have sense only at a worldwide scale and will impact our way of development. How can we reduce our energy consumption and greenhouse impact with answering everyone's essential needs at the same time? How can we invent a carbon-free economy in the North and preserve the big socio-economical equilibria at the same time? How can we get rid of poverty in the South without compromising the well-being of the future generations with an increase of CO2 emissions? Such difficulties cannot be overcome without innovations in terms of public policies. This book takes stock of the new possible instruments and policies at the global scale and involving fiscality, standards, investments and social justice. Content: 1 - the carbon threat: a changing climate and energies becoming scarce (the climate threat, an increasing energy insecurity); carbon and modern economy (human greenhouse gas emissions, a carbon-free well-being); governments and carbon control (a global challenge requiring an international control, the experiments era from Rio to the present day, the challenge of the state in front of the carbon threat); 2 - the political instruments of environment: standards as first instruments of climate public policies (standards efficiency in some sectors, standards limitations, standards and innovation); emissions quotas and market instruments (Kyoto protocol and CO2 market, the future of 'cap and trade' and of individual and regional quotas); carbon tax, fiscal instruments and new regulations (carbon tax as an alternative or a complement, other fiscal and para-fiscal instruments, new regulation instruments); investing in climate (managing the transition, governments as transition administrators). (J.S)

  17. Carbon based prosthetic devices

    Energy Technology Data Exchange (ETDEWEB)

    Devlin, D.J.; Carroll, D.W.; Barbero, R.S.; Archuleta, T. [Los Alamos National Lab., NM (US); Klawitter, J.J.; Ogilvie, W.; Strzepa, P. [Ascension Orthopedics (US); Cook, S.D. [Tulane Univ., New Orleans, LA (US). School of Medicine

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project objective was to evaluate the use of carbon/carbon-fiber-reinforced composites for use in endoprosthetic devices. The application of these materials for the metacarpophalangeal (MP) joints of the hand was investigated. Issues concerning mechanical properties, bone fixation, biocompatibility, and wear are discussed. A system consisting of fiber reinforced materials with a pyrolytic carbon matrix and diamond-like, carbon-coated wear surfaces was developed. Processes were developed for the chemical vapor infiltration (CVI) of pyrolytic carbon into porous fiber preforms with the ability to tailor the outer porosity of the device to provide a surface for bone in-growth. A method for coating diamond-like carbon (DLC) on the articulating surface by plasma-assisted chemical vapor deposition (CVD) was developed. Preliminary results on mechanical properties of the composite system are discussed and initial biocompatibility studies were performed.

  18. Black carbon in marine sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Van Breugel, P.

    1999-01-01

    Concentrations of black carbon were determined for a number of marine sediments. A comparison of black carbon based on thermal oxidation and hot concentrated nitric acid pretreatments revealed that the latter significantly overestimates combustion derived carbon phases. Black carbon accounts for abo

  19. Nano-Carbons as Theranostics

    Directory of Open Access Journals (Sweden)

    Zhuang Liu, Xing-Jie Liang

    2012-01-01

    Full Text Available Nano-carbons, including fullerenes, carbon nanoparticles, carbon nanotubes, graphene, and nano-diamonds, are an important class of nanostructures attracting tremendous interests in the past two decades. In this special issue, seven review articles and research reports are collected, to summarize and present the latest progress in the exploration of various nano-carbons for theranostic applications.

  20. Method for synthesizing carbon nanotubes

    Science.gov (United States)

    Fan, Hongyou

    2012-09-04

    A method for preparing a precursor solution for synthesis of carbon nanomaterials, where a polar solvent is added to at least one block copolymer and at least one carbohydrate compound, and the precursor solution is processed using a self-assembly process and subsequent heating to form nanoporous carbon films, porous carbon nanotubes, and porous carbon nanoparticles.

  1. Carbon isotope effects in carbonate systems

    Science.gov (United States)

    Deines, Peter

    2004-06-01

    Global carbon cycle models require a complete understanding of the δ 13C variability of the Earth's C reservoirs as well as the C isotope effects in the transfer of the element among them. An assessment of δ 13C changes during CO 2 loss from degassing magmas requires knowledge of the melt-CO 2 carbon isotope fractionation. In order to examine the potential size of this effect for silicate melts of varying composition, 13C reduced partition functions were computed in the temperature range 275 to 4000 K for carbonates of varying bond strengths (Mg, Fe, Mn, Sr, Ba, Pb, Zn, Cd, Li, and Na) and the polymorphs of calcite. For a given cation and a given pressure the 13C content increases with the density of the carbonate structure. For a given structure the tendency to concentrate 13C increases with pressure. The effect of pressure (‰/10 kbar) on the size of the reduced partition function of aragonite varies with temperature; in the pressure range 1 to 10 5 bars the change is given by: Δ 13C p average=-0.01796+0.06635∗ 10 3/T+0.006875∗ 10 6/T2 For calcite III the pressure effect is on average 1.4× larger than that for aragonite at all temperatures. The nature of the cation in a given structure type has a significant effect on the carbon isotope fractionation properties. The tendency to concentrate 13C declines in the series magnesite, aragonite, dolomite, strontianite, siderite, calcite, smithonite, witherite, rhodochrosite, otavite, cerrusite. For divalent cations a general expression for an estimation of the reduced partition function (β) from the reduced mass (μ = [M Cation × M Carbonate]/[M Cation + M Carbonate]) is: 1000 lnβ=(0.032367-0.072563∗ 10 3/T-0.01073∗ 10 6/T2)∗μ-14.003+29.953∗ 10 3/T+9.4610∗ 10 6/T2 For Mg-calcite the 13C content varies with the Mg concentration. The fractionation between Mg-calcite (X = mole fraction of MgCO 3) and calcite is given by: 1000 ln(α MgCalite- Calcite)=[0.013702-0.10957× 10 3/T+1.35940× 10 6/T2

  2. Aspects of carbon dioxide utilization

    Energy Technology Data Exchange (ETDEWEB)

    Omae, Iwao [Omae Research Laboratories, 335-23 Mizuno, Sayama, Saitama 350-1317 (Japan)

    2006-06-30

    Carbon dioxide reacts with hydrogen, alcohols, acetals, epoxides, amines, carbon-carbon unsaturated compounds, etc. in supercritical carbon dioxide or in other solvents in the presence of metal compounds as catalysts. The products of these reactions are formic acid, formic acid esters, formamides, methanol, dimethyl carbonate, alkylene carbonates, carbamic acid esters, lactones, carboxylic acids, polycarbonate (bisphenol-based engineering polymer), aliphatic polycarbonates, etc. Especially, the productions of formic acid, formic acid methyl ester and dimethylformamide with a ruthenium catalyst; dimethyl carbonate and urethanes with a dialkyltin catalyst; 2-pyrone with a nickel-phosphine catalyst; diphenyl carbonate with a lead phenoxide catalyst; the alternating copolymerization of carbon dioxide and epoxides with a zinc catalyst has attracted attentions as the industrial utilizations of carbon dioxide. The further development of these production processes is expected. (author)

  3. Organic modification of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The organic modification of carbon nanotubes is a novel research field being developed recently. In this article, the history and newest progress of organic modification of carbon nanotubes are reviewed from two aspects:organic covalent modification and organic noncovalent modification of carbon nanotubes. The preparation and properties of organic modified carbon nanotubes are discussed in detail. In addition, the prospective development of organic modification of carbon nanotubes is suggested.

  4. Industrial trial to produce a low clinker, low carbon cement

    Directory of Open Access Journals (Sweden)

    Vizcaíno-Andrés, L. M.

    2015-03-01

    Full Text Available A preliminary assessment of conditions for the industrial manufacture of a new cementitious system based on clinker-calcined clay and limestone, developed by the authors, referred as “low carbon cement” is presented. The new cement enables the substitution of more than 50% of the mass of clinker without compromising performance. The paper presents the follow-up of an industrial trial carried out in Cuba to produce 130 tonnes of the new cement at a cement plant. The new material proved to fulfill national standards in applications such as the manufacture of hollow concrete blocks and precast concrete. No major differences either in the rheological or mechanical properties were found when compared with Portland cement. Environmental assessment of the ternary cement was made, which included comparison with other blended cements produced industrially in Cuba. The new cement has proven to contribute to the reduction of above 30% of carbon emissions on cement manufacture.Se presenta la evaluación preliminar de las condiciones de fabricación industrial de un nuevo sistema cementicio a partir del empleo de clínquer; arcillas calcinadas y piedra caliza; desarrollado por los autores; denominado “cemento de bajo carbono”. El nuevo cemento posibilita la reducción de más de un 50% de la masa de clínquer; sin comprometer el comportamiento del material. El presente trabajo presenta el monitoreo de la producción industrial en una planta en Cuba; de 130 t del nuevo cemento. El cemento obtenido cumple con las regulaciones nacionales de calidad y su empleo tiene similar rendimiento que el cemento Pórtland para la producción de bloques y hormigón de 25 MPa. Se realiza el análisis de impacto ambiental del cemento ternario mediante la comparación con otros cementos producidos industrialmente. El nuevo cemento puede contribuir a la reducción de más del 30% de las emisiones de CO2 asociadas a la manufactura de cemento.

  5. Electromagnetic interference shielding with Portland cement paste containing carbon materials and processed fly ash

    Directory of Open Access Journals (Sweden)

    Zornoza, E.

    2010-12-01

    Full Text Available The study described in this article explored the effect of adding different types of carbon materials (graphite powder and three types of carbon fibre, fly ash (with 5.6%, 15.9% and 24.3% Fe2O3, and a mix of both on electromagnetic interference (EMI shielding in Portland cement pastes. The parameters studied included the type and aspect ratio of the carbonic material, composite material thickness, the frequency of the incident electromagnetic radiation and the percentage of the magnetic fraction in the fly ash. The findings showed that the polyacrylonitrile-based carbon fibres, which had the highest aspect ratio, provided more effective shielding than any of the other carbon materials studied. Shielding was more effective in thicker specimens and at higher radiation frequencies. Raising the magnetic fraction of the fly ash, in turn, also enhanced paste shielding performance. Finally, adding both carbon fibre and fly ash to the paste resulted in the most effective EMI shielding as a result of the synergies generated.

    En el presente trabajo se investiga la influencia de la adición de diferentes tipos de materiales carbonosos (polvo de grafito y 3 tipos de fibra de carbono, de una ceniza volante con diferentes contenidos de fase magnética (5,6%, 15,9% y 24,3% de Fe2O3 y de una mezcla de ambos, sobre la capacidad de apantallar interferencias electromagnéticas de pastas de cemento Pórtland. Entre los parámetros estudiados se encuentra: el tipo de material carbonoso, la relación de aspecto del material carbonoso, el espesor del material compuesto, la frecuencia de la radiación electromagnética incidente y el porcentaje de fracción magnética en la ceniza volante. Los resultados obtenidos indican que entre los materiales carbonosos estudiados son las fibras de carbono basadas en poliacrilonitrilo con una mayor relación de aspecto las que dan mejores resultados de apantallamiento. Al aumentar

  6. Carbon dioxide and climate

    International Nuclear Information System (INIS)

    Global climate change is a serious environmental concern, and the US has developed ''An Action Agenda'' to deal with it. At the heart of the US effort is the US Global Change Research Program (USGCRP), which has been developed by the Committee on Earth and Environmental Sciences (CEES) of the Federal Coordinating Council for Sciences, Engineering, and Technology (FCCSET). The USGCRP will provide the scientific basis for sound policy making on the climate-change issue. The DOE contribution to the USGCRP is the Carbon Dioxide Research Program, which now places particular emphasis on the rapid improvement of the capability to predict global and regional climate change. DOE's Carbon Dioxide Research Program has been addressing the carbon dioxide-climate change connection for more than twelve years and has provided a solid scientific foundation for the USGCRP. The expansion of the DOE effort reflects the increased attention that the Department has placed on the issue and is reflected in the National Energy Strategy (NES) that was released in 1991. This Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1991 and gives a brief overview of objectives, organization, and accomplishments. The Environmental Sciences Division of the Office of Health and Environmental Research, Office of Energy Research supports a Carbon Dioxide Research Program to determine the scientific linkage between the rise of greenhouse gases in the atmosphere, especially carbon dioxide, and climate and vegetation change. One facet is the Core CO2 Program, a pioneering program that DOE established more than 10 years ago to understand and predict the ways that fossil-fuel burning could affect atmospheric CO2 concentration, global climate, and the Earth's biosphere. Major research areas are: global carbon cycle; climate detection and models of climate change; vegetation research; resource analysis; and, information and integration

  7. Measurement of carbon capture efficiency and stored carbon leakage

    Science.gov (United States)

    Keeling, Ralph F.; Dubey, Manvendra K.

    2013-01-29

    Data representative of a measured carbon dioxide (CO.sub.2) concentration and of a measured oxygen (O.sub.2) concentration at a measurement location can be used to determine whether the measured carbon dioxide concentration at the measurement location is elevated relative to a baseline carbon dioxide concentration due to escape of carbon dioxide from a source associated with a carbon capture and storage process. Optionally, the data can be used to quantify a carbon dioxide concentration increase at the first location that is attributable to escape of carbon dioxide from the source and to calculate a rate of escape of carbon dioxide from the source by executing a model of gas-phase transport using at least the first carbon dioxide concentration increase. Related systems, methods, and articles of manufacture are also described.

  8. Carbon nanotube core graphitic shell hybrid fibers.

    Science.gov (United States)

    Hahm, Myung Gwan; Lee, Jae-Hwang; Hart, Amelia H C; Song, Sung Moo; Nam, Jaewook; Jung, Hyun Young; Hashim, Daniel Paul; Li, Bo; Narayanan, Tharangattu N; Park, Chi-Dong; Zhao, Yao; Vajtai, Robert; Kim, Yoong Ahm; Hayashi, Takuya; Ku, Bon-Cheol; Endo, Morinobu; Barrera, Enrique; Jung, Yung Joon; Thomas, Edwin L; Ajayan, Pulickel M

    2013-12-23

    A carbon nanotube yarn core graphitic shell hybrid fiber was fabricated via facile heat treatment of epoxy-based negative photoresist (SU-8) on carbon nanotube yarn. The effective encapsulation of carbon nanotube yarn in carbon fiber and a glassy carbon outer shell determines their physical properties. The higher electrical conductivity (than carbon fiber) of the carbon nanotube yarn overcomes the drawbacks of carbon fiber/glassy carbon, and the better properties (than carbon nanotubes) of the carbon fiber/glassy carbon make up for the lower thermal and mechanical properties of the carbon nanotube yarn via synergistic hybridization without any chemical doping and additional processes. PMID:24224730

  9. Terrestrial Carbon Cycle Variability

    Science.gov (United States)

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2, temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y -1) with respect to a large and uncertain background (123 +/- 4 Pg-C y -1), and

  10. Carbon fuel particles used in direct carbon conversion fuel cells

    Science.gov (United States)

    Cooper, John F.; Cherepy, Nerine

    2012-10-09

    A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

  11. Low carbon steel corrosion damage prediction in rural and urban environments

    Directory of Open Access Journals (Sweden)

    Díaz, V.

    2003-12-01

    Full Text Available This paper presents an Artificial Neural Network (ANN model for the damage function of carbon steel, expressed in μm of corrosion penetration as a function of environmental variables. Working in the context of the Iberoamerican Atmospheric Corrosion Map Project, the experimental data comes as result of the corrosion of low alloy steel subtracts in three test sites in Uruguay, South America. In addition, we included experimental values obtained from short time kinetics studies, corresponding to special series from one of the sites. The ANN numerical model shows attractive results regarding goodness of fit and residual distributions. It achieves a RMSE value of 0.5 μm while a classical regression model lies in the range of 4.1 μm. Furthermore, a properly adjusted ANN model can be useful in the prediction of corrosion damage under different climatological and pollution conditions, while linear models cannot.

    Este artículo presenta la metodología de las redes neuronales artificiales (RNA como solución para el modelado de los valores experimentales obtenidos en los procesos de corrosión atmosférica. Se desarrolla el modelo de RNA para la función de daño, expresada en μm de penetración para el acero de bajo carbono en función de las variables medioambientales, en el contexto del Proyecto MICAT (Mapa Iberoamericano de Corrosión Atmosférica y programas de experimentación propios. Los datos experimentales son resultado de los estudios de calibración sobre sustratos ferrosos en tres sitios del territorio uruguayo, Sudamérica. Se incluyen, además, los valores experimentales obtenidos en los estudios de cinéticas iniciales, correspondientes a series especiales de cortos tiempos de exposición en una de las estaciones de ensayo. El modelo numérico de RNA muestra resultados con un valor de RMSE de 0,5 μm, en tanto el modelo de regresión clásico arroja un valor de 4,1 μm.

  12. Flexible Carbon Aerogels

    Directory of Open Access Journals (Sweden)

    Marina Schwan

    2016-09-01

    Full Text Available Carbon aerogels are highly porous materials with a large inner surface area. Due to their high electrical conductivity they are excellent electrode materials in supercapacitors. Their brittleness, however, imposes certain limitations in terms of applicability. In that context, novel carbon aerogels with varying degree of flexibility have been developed. These highly porous, light aerogels are characterized by a high surface area and possess pore structures in the micrometer range, allowing for a reversible deformation of the aerogel network. A high ratio of pore size to particle size was found to be crucial for high flexibility. For dynamic microstructural analysis, compression tests were performed in-situ within a scanning electron microscope allowing us to directly visualize the microstructural flexibility of an aerogel. The flexible carbon aerogels were found to withstand between 15% and 30% of uniaxial compression in a reversible fashion. These findings might stimulate further research and new application fields directed towards flexible supercapacitors and batteries.

  13. Securing tropical forest carbon

    DEFF Research Database (Denmark)

    Scharlemann, Jörn P. W.; Kapos, Valerie; Campbell, Alison;

    2010-01-01

    Forest loss and degradation in the tropics contribute 6-17% of all greenhouse gas emissions. Protected areas cover 217.2 million ha (19.6%) of the world's humid tropical forests and contain c. 70.3 petagrams of carbon (Pg C) in biomass and soil to 1 m depth. Between 2000 and 2005, we estimate...... that 1.75 million ha of forest were lost from protected areas in humid tropical forests, causing the emission of 0.25-0.33 Pg C. Protected areas lost about half as much carbon as the same area of unprotected forest. We estimate that the reduction of these carbon emissions from ongoing deforestation......, although certainly not sufficient, component of an overall strategy for reducing emissions from deforestation and forest degradation (REDD)...

  14. Pyrolyzed carbon film diodes.

    Science.gov (United States)

    Morton, Kirstin C; Tokuhisa, Hideo; Baker, Lane A

    2013-11-13

    We have previously reported pyrolyzed parylene C (PPC) as a conductive carbon electrode material for use with micropipets, atomic force microscopy probes, and planar electrodes. Advantages of carbon electrode fabrication from PPC include conformal coating of high-aspect ratio micro/nanoscale features and the benefits afforded by chemical vapor deposition of carbon polymers. In this work, we demonstrate chemical surface doping of PPC through the use of previously reported methods. Chemically treated PPC films are characterized by multiple spectroscopic and electronic measurements. Pyrolyzed parylene C and doped PPC are used to construct diodes that are examined as both p-n heterojunction and Schottky barrier diodes. Half-wave rectification is achieved with PPC diodes and demonstrates the applicability of PPC as a conductive and semiconductive material in device fabrication. PMID:24090451

  15. Horizontal carbon nanotube alignment.

    Science.gov (United States)

    Cole, Matthew T; Cientanni, Vito; Milne, William I

    2016-09-21

    The production of horizontally aligned carbon nanotubes offers a rapid means of realizing a myriad of self-assembled near-atom-scale technologies - from novel photonic crystals to nanoscale transistors. The ability to reproducibly align anisotropic nanostructures has huge technological value. Here we review the present state-of-the-art in horizontal carbon nanotube alignment. For both in and ex situ approaches, we quantitatively assess the reported linear packing densities alongside the degree of alignment possible for each of these core methodologies. PMID:27546174

  16. Nanotube composite carbon fibers

    Science.gov (United States)

    Andrews, R.; Jacques, D.; Rao, A. M.; Rantell, T.; Derbyshire, F.; Chen, Y.; Chen, J.; Haddon, R. C.

    1999-08-01

    Single walled carbon nanotubes (SWNTs) were dispersed in isotropic petroleum pitch matrices to form nanotube composite carbon fibers with enhanced mechanical and electrical properties. We find that the tensile strength, modulus, and electrical conductivity of a pitch composite fiber with 5 wt % loading of purified SWNTs are enhanced by ˜90%, ˜150%, and 340% respectively, as compared to the corresponding values in unmodified isotropic pitch fibers. These results serve to highlight the potential that exits for developing a spectrum of material properties through the selection of the matrix, nanotube dispersion, alignment, and interfacial bonding.

  17. Carbon Nanotube Solar Cells

    OpenAIRE

    Klinger, Colin; Patel, Yogeshwari; Postma, Henk W. Ch.

    2012-01-01

    We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabr...

  18. Carbon cycle makeover

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Kump, Lee R.

    2013-01-01

    remaining in sediments after respiration leave a residual of oxygen in the atmosphere. The source of oxygen to the atmosphere represented by organic matter burial is balanced by oxygen sinks associated with rock weathering and chemical reaction with volcanic gases. This is the long-term carbon and oxygen...... geochemical cycle. But Earth is an old planet, and oxygen levels have changed through time (2). On page 540 of this issue, Schrag et al. (3) challenge the most commonly used geochemical approach to assess long-term changes in the coupled oxygen and carbon cycles....

  19. Pitch carbon microsphere composite

    Science.gov (United States)

    Price, H. L.; Nelson, J. B.

    1977-01-01

    Petroleum pitch carbon microspheres were prepared by flash heating emulsified pitch and carbonizing the resulting microspheres in an inert atmosphere. Microsphere composites were obtained from a mixture of microspheres and tetraester precursor pyrrone powder. Scanning electron micrographs of the composite showed that it was an aggregate of microspheres bonded together by the pyrrone at the sphere contact points, with voids in and among the microspheres. Physical, thermal, and sorption properties of the composite are described. Composite applications could include use as a honeycomb filler in elevated-temperature load-bearing sandwich boards or in patient-treatment tables for radiation treatment of tumors.

  20. Application of digital image processing to determine the causes of failures in SAE 1018 carbon steel; Aplicacion del procesamiento digital de imagenes para la determinacion de las causas que provocan fallas en el acero al carbono SAE 1018

    Energy Technology Data Exchange (ETDEWEB)

    Bolanos-Rodriguez, E [Escuela Superior de Tizayuca, Universidad Autonoma del Estado de Hidalgo, Tizayuca, Hidalgo (Mexico)]. E-mail: bola7112@yahoo.com.mx; Gonzalez-Islas, J.C. [Universidad Tecnologica de Tulancingo, Tulancingo, Hidalgo (Mexico)]. E-mail: juanc.gonzalez@utec-tgo.edu.mx; Felipe-Riveron, E.M. [Centro de Investigacion en Computacion, Instituto Politecnico Nacional, Mexico, D.F. (Mexico)]. E-mail: edgardo@cic.ipn.mx

    2013-03-15

    The research is focused on determining the causes of failures in the SAE 1018 carbon steel that is used in pipes carrying drinking water. Digital processing of images captured by photomicrographs by scanning electron microscopy coupled with the technique of X-ray microanalysis. The results demonstrate that the low quality of the raw materials and the manufacturing process of steel are the reasons for the occurrence of cracks observed in the material. [Spanish] La investigacion se centra en determinar las causas que provocan fallas en el acero al carbono SAE 1018 que es utilizado en tuberias que transportan agua potable. Se emplea el procesamiento digital de imagenes de las microfotografias captadas por medio de microscopia electronica de barrido, unido a la tecnica de microanalisis de rayos X. Los resultados obtenidos demuestran que la baja calidad de las materias primas y el proceso de manufactura del acero son las razones de la ocurrencia de fisuras observadas en el material.

  1. Method for production of carbon nanofiber mat or carbon paper

    Energy Technology Data Exchange (ETDEWEB)

    Naskar, Amit K.

    2015-08-04

    Method for the preparation of a non-woven mat or paper made of carbon fibers, the method comprising carbonizing a non-woven mat or paper preform (precursor) comprised of a plurality of bonded sulfonated polyolefin fibers to produce said non-woven mat or paper made of carbon fibers. The preforms and resulting non-woven mat or paper made of carbon fiber, as well as articles and devices containing them, and methods for their use, are also described.

  2. Dynamic carbon allocation significantly changed land carbon sink and carbon pool sizes

    Science.gov (United States)

    Xia, J.; Yuan, W.

    2015-12-01

    The allocation of photosynthate among the plant components (e.g., leaves, stems, and roots) plays an important role in regulating plant growth, competition, and terrestrial carbon cycle. However, the carbon allocation process is still a weak part in the earth system models (ESMs). In this study, the Integrated BIosphere Simulator (IBIS) model coupled with a dynamic carbon allocation model (IBISAL) is used to explore the impact of carbon allocation on the terrestrial carbon cycle. This dynamic carbon allocation model suggests that plants should allocate the largest part of carbon to the plant components which need to capture the most limiting resources, such as light, water and nitrogen. In comparison to the results of original IBIS model using fixed allocation ratios, the net ecosystem productivity, global biomass and soil organic carbon simulated by IBISAL model decreased by13.4% , 9.9% and 20.8%, respectively . The dynamic allocation scheme tends to benefit roots allocation. Because roots had short turnover times, high roots allocation led to the decreases of global carbon sink and carbon pool sizes. The observations showed that the carbon allocation ratios changed with temperature and precipitation. The dynamic carbon allocation model could reproduce this phenomenon correctly. The results show that the dynamic carbon allocation ratios of boreal evergreen forests and C3 grasses are consistent well with the observations. However, the IBISAL, and another three ESMs (i.e., CESM1-BGC, IPSL-CM5A-MR and NorESM1-ME models) adopting dynamic allocation scheme overestimated the stems allocation of tropical forests. This study shows the substantial influences of carbon allocation on the carbon sink and carbon pool sizes. Therefore, improving estimations of carbon allocation by ESMs are an important and effective path to reduce uncertainties in the global carbon cycle simulation and climate change prediction.

  3. Catalytic graphitization of carbon/carbon composites by lanthanum oxide

    Institute of Scientific and Technical Information of China (English)

    ZHANG Can; LU Guimin; SUN Ze; YU Jianguo

    2012-01-01

    Graphitized carbon/carbon composites were prepared by the process of catalytic graphitization with the rare-earth catalyst,lanthanum oxide (La2O3),in order to increase the degree of graphitization and reduce the electrical resistivity.The modified coal tar pitch and coal-based needle coke were used as carbon source,and a small amount of La2O3 was added to catalyze the graphitization of the disordered carbon materials.The effects of La2O3 catalyst on the graphitization degree and microstructure oftbe carbon/carbon composites were investigated by X-ray diffraction,scanning electron microscopy,and Raman spectroscopy.The results showed that La2O3 promoted the formation of more perfect and larger crystallites,and improved the electrical/mechanical properties of carbon/carbon composites.Carbon/carbon composites with a lower electrical resistivity (7.0 μΩ·m) could be prepared when adding 5 wt.% La2O3 powder with heating treatment at 2800 ℃.The catalytic effect of La2O3 for the graphitization of carbon/carbon composites was analyzed.

  4. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Memos Regarding Some of the Hazards Associated with Engine-Driven Generators, 2004-2014 January 07, 2016 Non- ... Investigations Associated with Non-Fire Carbon Monoxide from Engine-Driven Generators and Other Engine-Driven Tools, 2004– ...

  5. Carbon Monoxide Poisoning

    OpenAIRE

    Wray, Alisa

    2016-01-01

    Audience: This oral boards case is appropriate for all emergency medicine learners (residents, interns, and medical students). Introduction: Carbon monoxide (CO) is a colorless and odorless gas that typically results from combustion. It binds hemoglobin, dissociating oxygen, causing headache, weakness, confusion and possible seizure or coma. Pulse oxygen levels may be falsely elevated. Practitioners should maintain a high in...

  6. Closing carbon cycles

    NARCIS (Netherlands)

    Patel, Martin

    2001-01-01

    Fossil fuels are used as raw materials for the manufacture of synthetic organic materials, e.g. plastics, fibres, synthetic rubber, paints, solvents, fertilisers, surfactants, lubricants and bitumen. Since fossil carbon is embodied in these products they may be particularly relevant to climate ch

  7. Carbon Monoxide Information Center

    Medline Plus

    Full Text Available ... Flickr SlideShare All Pages & Documents Recalls & News Releases Home Recalls CPSC Recall API Recall Lawsuits Recalls by ... CO Poster Contest Toy Recall Statistics Pool Safely Home / Safety Education / Safety Education Centers En Español Carbon ...

  8. Carbon nanotube solar cells.

    Directory of Open Access Journals (Sweden)

    Colin Klinger

    Full Text Available We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabricate using a spray-paint technique. We observe that cells with a lower concentration of carbon nanotubes on the active semiconducting electrode perform better than cells with a higher concentration of nanotubes. This effect is contrary to the expectation that a larger number of nanotubes would lead to more photoconversion and therefore more power generation. We attribute this to the presence of metallic nanotubes that provide a short for photo-excited electrons, bypassing the load. We demonstrate optimization strategies that improve cell efficiency by orders of magnitude. Once it is possible to make semiconducting-only carbon nanotube films, that may provide the greatest efficiency improvement.

  9. Skallerup Klit's carbon footprint

    DEFF Research Database (Denmark)

    Zacho, Kristina Overgaard; Ørnstrup, Niels Holm; Zimmermann, Tine Marquard;

    by offsetting and without making actual emission reductions. Therefore the purpose of this study is to present recommendations on how Skallerup Klit can build up their business strategy using Carbon Footprint (CFP) as a tool. The CPF is calculated and assessed by using financial data in an Input-output LCA...

  10. Polyimide/carbon Nanocomposites

    Science.gov (United States)

    Harris, Frank W.

    2003-01-01

    The goal of this product is to design and characterize well-defined conductive nanocomposite materials. The materials will be composed of a polymer matrix composed of rigid-backbone polyimides, and will be filled with modified or unmodified multi-walled carbon nanotubes (MWNTs). The ultimate design of this project is to create composite materials with optical clarity and a high conductivity.

  11. City Carbon Footprint Networks

    Directory of Open Access Journals (Sweden)

    Guangwu Chen

    2016-07-01

    Full Text Available Progressive cities worldwide have demonstrated political leadership by initiating meaningful strategies and actions to tackle climate change. However, the lack of knowledge concerning embodied greenhouse gas (GHG emissions of cities has hampered effective mitigation. We analyse trans-boundary GHG emission transfers between five Australian cities and their trading partners, with embodied emission flows broken down into major economic sectors. We examine intercity carbon footprint (CF networks and disclose a hierarchy of responsibility for emissions between cities and regions. Allocations of emissions to households, businesses and government and the carbon efficiency of expenditure have been analysed to inform mitigation policies. Our findings indicate that final demand in the five largest cities in Australia accounts for more than half of the nation’s CF. City households are responsible for about two thirds of the cities’ CFs; the rest can be attributed to government and business consumption and investment. The city network flows highlight that over half of emissions embodied in imports (EEI to the five cities occur overseas. However, a hierarchy of GHG emissions reveals that overseas regions also outsource emissions to Australian cities such as Perth. We finally discuss the implications of our findings on carbon neutrality, low-carbon city concepts and strategies and allocation of subnational GHG responsibility.

  12. Bioenergy, the Carbon Cycle, and Carbon Policy

    Science.gov (United States)

    Kammen, D. M.

    2003-12-01

    The evolving energy and land-use policies across North America and Africa provide critical case studies in the relationship between regional development, the management of natural resources, and the carbon cycle. Over 50 EJ of the roughly 430 EJ total global anthropogenic energy budget is currently utilized in the form of direct biomass combustion. In North America 3 - 4 percent of total energy is derived from biomass, largely in combined heat and power (CHP) combustion applications. By contrast Africa, which is a major consumer of 'traditional' forms of biomass, uses far more total bioenergy products, but largely in smaller batches, with quantities of 0.5 - 2 tons/capita at the household level. Several African nations rely on biomass for well over 90 percent of household energy, and in some nations major portions of the industrial energy supply is also derived from biomass. In much of sub-Saharan Africa the direct combustion of biomass in rural areas is exceeded by the conversion of wood to charcoal for transport to the cities for household use there. There are major health, and environmental repercussions of these energy flows. The African, as well as Latin American and Asian charcoal trade has a noticeable signature on the global greenhouse gas cycles. In North America, and notably Scandinavia and India as well, biomass energy and emerging conversion technologies are being actively researched, and provide tremendous opportunities for the evolution of a sustainable, locally based, energy economy for many nations. This talk will examine aspects of these current energy and carbon flows, and the potential that gassification and new silvicultural practices hold for clean energy systems in the 21st century. North America and Africa will be examined in particular as both sources of innovation in this field, and areas with specific promise for application of these energy technologies and biomass/land use practices to further energy and global climate management.

  13. Método de Cobb na escoliose idiopática do adolescente: avaliação dos ângulos obtidos com goniômetros articulados e fixos Método de Cobb en la escoliosis idiopática del adolescente: evaluación de los ángulos obtenidos con goniómetros articulados y fijos Cobb method in adolescent idiopathic scoliosis-angle: evaluation with articulated and fixed goniometers

    Directory of Open Access Journals (Sweden)

    Ana Laura Loyola Munhoz da Cunha

    2009-06-01

    ômetros na curva M parecem não estar relacionadas ao equipamento utilizado.OBJETIVO: determinar la variación del ángulo de Cobb en la escoliosis idiopática del adolescente, por medio de la utilización de dos tipos de goniómetros calibrados: articulado y fijo. MÉTODOS: ocho radiografías de pacientes con escoliosis idiopática del adolescente, obtenidas en aparato digital, con curva primaria grave (encima de 30 grados fueron seleccionadas. Las imágenes de cada una de las ocho radiografías de las escoliosis fueron procesadas e impresas 36 veces en película radiográfica (totalizando 228 imágenes. Las curvas escolióticas tanto primarias así como secundarias (17 curvas, tuvieron sus vértebras límite predeterminadas y fueron medidas, por seis ortopedistas, actuando en el área de cirugía de la columna vertebral. Cada examinador recibió alternadamente un conjunto de las ocho escoliosis, 17 curvas para ser medidas con un goniómetro sea articulado o fijo siempre acompañado de un lápiz apropiado para medir radiografías. Los seis ortopedistas midieron cada una de las 17 curvas en seis ocasiones diferentes, siendo que tres de ellas con o goniómetro articulado y tres con el goniómetro fijo. El intervalo entre la entrega de cada conjunto no fue inferior a 24 horas. El análisis estadístico fue hecho por medio de testes pareados, para evaluar la variación entre los diferentes goniómetros por los mismos individuos, y por comparaciones por medio del porcentaje, promedio, coeficientes e índices de variación obtenidos para las demás variables estudiadas (variación intra e inter observadores. RESULTADOS: entre las 17 curvas evaluadas (A a Q, solo la curva M mostró diferencias estadísticamente significativas entre los valores angulares obtenidos con el goniómetro articulado (promedio de 33.3+9.1º y con el goniómetro fijo (27.9+4.2º, en el cual p=0.009. CONCLUSIONES: no existen diferencias significativas entre los valores obtenidos con el goni

  14. Carbon nanotube macroelectronics

    Science.gov (United States)

    Zhang, Jialu

    In this dissertation, I discuss the application of carbon nanotubes in macroelectronis. Due to the extraordinary electrical properties such as high intrinsic carrier mobility and current-carrying capacity, single wall carbon nanotubes are very desirable for thin-film transistor (TFT) applications such as flat panel display, transparent electronics, as well as flexible and stretchable electronics. Compared with other popular channel material for TFTs, namely amorphous silicon, polycrystalline silicon and organic materials, nanotube thin-films have the advantages of low-temperature processing compatibility, transparency, and flexibility, as well as high device performance. In order to demonstrate scalable, practical carbon nanotube macroelectroncis, I have developed a platform to fabricate high-density, uniform separated nanotube based thin-film transistors. In addition, many other essential analysis as well as technology components, such as nanotube film density control, purity and diameter dependent semiconducting nanotube electrical performance study, air-stable n-type transistor fabrication, and CMOS integration platform have also been demonstrated. On the basis of the above achievement, I have further demonstrated various kinds of applications including AMOLED display electronics, PMOS and CMOS logic circuits, flexible and transparent electronics. The dissertation is structured as follows. First, chapter 1 gives a brief introduction to the electronic properties of carbon nanotubes, which serves as the background knowledge for the following chapters. In chapter 2, I will present our approach of fabricating wafer-scale uniform semiconducting carbon nanotube thin-film transistors and demonstrate their application in display electronics and logic circuits. Following that, more detailed information about carbon nanotube thin-film transistor based active matrix organic light-emitting diode (AMOLED) displays is discussed in chapter 3. And in chapter 4, a technology to

  15. Carbon sinks in temperate forests

    NARCIS (Netherlands)

    Martin, P.H.; Nabuurs, G.J.; Aubinet, M.; Karjalainen, T.; Vine, E.L.; Kinsman, J.; Heath, L.S.

    2001-01-01

    In addition to being scientifically exciting, commercially important, and environmentally essential, temperate forests have also become a key diplomatic item in international climate negotiations as potential sinks for carbon. This review presents the methods used to estimate carbon sequestration, i

  16. Carbon Monoxide (CO) Poisoning Prevention

    Science.gov (United States)

    ... What's this? Submit Button Past Emails CDC Features Carbon Monoxide (CO) Poisoning Prevention Language: English Español (Spanish) ... tornadoes), using alternative sources of power can cause carbon monoxide (CO) to build up in a home ...

  17. Dewatering Peat With Activated Carbon

    Science.gov (United States)

    Rohatgi, N. K.

    1984-01-01

    Proposed process produces enough gas and carbon to sustain itself. In proposed process peat slurry is dewatered to approximately 40 percent moisture content by mixing slurry with activated carbon and filtering with solid/liquid separation techniques.

  18. ROE Carbon Storage - Percent Change

    Data.gov (United States)

    U.S. Environmental Protection Agency — This polygon dataset depicts the percentage change in the amount of carbon stored in forests in counties across the United States, based on the difference in carbon...

  19. Boron nitride converted carbon fiber

    Energy Technology Data Exchange (ETDEWEB)

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  20. Templated Growth of Carbon Nanotubes

    Science.gov (United States)

    Siochik Emilie J. (Inventor)

    2007-01-01

    A method of growing carbon nanotubes uses a synthesized mesoporous si lica template with approximately cylindrical pores being formed there in. The surfaces of the pores are coated with a carbon nanotube precu rsor, and the template with the surfaces of the pores so-coated is th en heated until the carbon nanotube precursor in each pore is convert ed to a carbon nanotube.

  1. Carbon balance in Mediterranean ecosystems

    OpenAIRE

    Correia, Alexandra Cristina Pires

    2013-01-01

    Forests play an important role in climate change mitigation as they sequester and store carbon dioxide (CO2) from the atmosphere. The aim of this thesis was to investigate forest carbon balance in its main compartments: tress, understory and soils. We present methods to estimate carbon stock in biomass of stone pine stands in south Portugal. Allometric models, as well as conversion and expansion factors were presented allowing the quantification of stand carbon stocks irrespect...

  2. Apparatus for producing carbon-coated nanoparticles and carbon nanospheres

    Science.gov (United States)

    Perry, W. Lee; Weigle, John C.; Phillips, Jonathan

    2015-10-20

    An apparatus for producing carbon-coated nano- or micron-scale particles comprising a container for entraining particles in an aerosol gas, providing an inlet for carbon-containing gas, providing an inlet for plasma gas, a proximate torch for mixing the aerosol gas, the carbon-containing gas, and the plasma gas, bombarding the mixed gases with microwaves, and providing a collection device for gathering the resulting carbon-coated nano- or micron-scale particles. Also disclosed is a method and apparatus for making hollow carbon nano- or micro-scale spheres.

  3. Designing carbon markets, Part II: Carbon markets in space

    International Nuclear Information System (INIS)

    This paper analyses the design of carbon markets in space (i.e., geographically). It is part of a twin set of papers that, starting from first principles, ask what an optimal global carbon market would look like by around 2030. Our focus is on firm-level cap-and-trade systems, although much of what we say would also apply to government-level trading and carbon offset schemes. We examine the 'first principles' of spatial design to maximise flexibility and to minimise costs, including key design issues in linking national and regional carbon markets together to create a global carbon market.

  4. Green Carbon : The role of natural forests in carbon storage

    OpenAIRE

    Keith, Heather; Lindenmayer, David B; Mackey, Brendan; Berry, Sandra L.

    2008-01-01

    The colour of carbon matters. Green carbon is the carbon stored in the plants and soil of natural ecosystems and is a vital part of the global carbon cycle. This report is the first in a series that examines the role of natural forests in the storage of carbon, the impacts of human land use activities, and the implications for climate change policy nationally and internationally. REDD (“reducing emissions from deforestation and degradation”) is now part of the agenda for the “Bali Action Plan...

  5. Wool Research Makes Carbon Headway

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    A collective of woolgrowers, scientists and carbon specialists the Wool Carbon Alliance (WCA) has reviewed the latest research role in the natural carbon cycle, from woolgrowing properties around the globe known as on wool's to homes around the globe .

  6. Carbon dioxide as a carbon source in organic transformation: carbon-carbon bond forming reactions by transition-metal catalysts.

    OpenAIRE

    Tsuji, Yasushi; Fujihara, Tetsuaki

    2012-01-01

    Recent carbon-carbon bond forming reactions of carbon dioxide with alkenes, alkynes, dienes, aryl zinc compounds, aryl boronic esters, aryl halides, and arenes having acidic C-H bonds are reviewed in which transition-metal catalysts play an important role.

  7. Carbon nanotube junctions and devices

    NARCIS (Netherlands)

    Postma, H.W.Ch.

    2001-01-01

    In this thesis Postma presents transport experiments performed on individual single-wall carbon nanotubes. Carbon nanotubes are molecules entirely made of carbon atoms. The electronic properties are determined by the exact symmetry of the nanotube lattice, resulting in either metallic or semiconduct

  8. Guideposts for Low Carbon Finance

    International Nuclear Information System (INIS)

    The author proposes four guideposts for efficient low carbon finance: remove subsidies for high-carbon technologies, improve the cost-effectiveness of low-carbon subsidies, encourage private sector innovation and maintain transparent public policy tools that support cost-benefit accounting

  9. CARBON IN FORESTS: QUALITY MATTERS

    Science.gov (United States)

    The nature of carbon in forests is discussed from the perspective of carbon sequestration and global climate change. Carbon inventories, specifically in the area of land use and forestry are reviewed for the Pacific Northwest. Areas vulnerable to climate change with respect to ca...

  10. Carbon Sequestration in Agricultural Soils

    OpenAIRE

    World Bank

    2009-01-01

    The purpose of this report is to improve the knowledge base for facilitating investments in land management technologies that sequester soil organic carbon. While there are many studies on soil carbon sequestration, there is no single unifying volume that synthesizes knowledge on the impact of different land management practices on soil carbon sequestration rates across the world. A meta-a...

  11. Low Carbon Development of Hainan

    Science.gov (United States)

    Yi, Feng; Kun, Zhang

    With the construction of Hainan international tourism island rising to a national strategy level, the green growth pattern based on low carbon objectives will become a significant part in the development of Hainan's economy. In this paper, low carbon electric power system and differentiation service will be discussed, and some opinions were brought up to have a good impact on Hainan's low carbon development.

  12. Accelerated carbonation of brucite in mine tailings for carbon sequestration.

    Science.gov (United States)

    Harrison, Anna L; Power, Ian M; Dipple, Gregory M

    2013-01-01

    Atmospheric CO(2) is sequestered within ultramafic mine tailings via carbonation of Mg-bearing minerals. The rate of carbon sequestration at some mine sites appears to be limited by the rate of CO(2) supply. If carbonation of bulk tailings were accelerated, large mines may have the capacity to sequester millions of tonnes of CO(2) annually, offsetting mine emissions. The effect of supplying elevated partial pressures of CO(2) (pCO(2)) at 1 atm total pressure, on the carbonation rate of brucite [Mg(OH)(2)], a tailings mineral, was investigated experimentally with conditions emulating those at Mount Keith Nickel Mine (MKM), Western Australia. Brucite was carbonated to form nesquehonite [MgCO(3) · 3H(2)O] at a rate that increased linearly with pCO(2). Geochemical modeling indicated that HCO(3)(-) promoted dissolution accelerated brucite carbonation. Isotopic and aqueous chemistry data indicated that equilibrium between CO(2) in the gas and aqueous phases was not attained during carbonation, yet nesquehonite precipitation occurred at equilibrium. This implies CO(2) uptake into solution remains rate-limiting for brucite carbonation at elevated pCO(2), providing potential for further acceleration. Accelerated brucite carbonation at MKM offers the potential to offset annual mine emissions by ~22-57%. Recognition of mechanisms for brucite carbonation will guide ongoing work to accelerate Mg-silicate carbonation in tailings. PMID:22770473

  13. Carbon dioxide conversion over carbon-based nanocatalysts.

    Science.gov (United States)

    Khavarian, Mehrnoush; Chai, Siang-Piao; Mohamed, Abdul Rahman

    2013-07-01

    The utilization of carbon dioxide for the production of valuable chemicals via catalysts is one of the efficient ways to mitigate the greenhouse gases in the atmosphere. It is known that the carbon dioxide conversion and product yields are still low even if the reaction is operated at high pressure and temperature. The carbon dioxide utilization and conversion provides many challenges in exploring new concepts and opportunities for development of unique catalysts for the purpose of activating the carbon dioxide molecules. In this paper, the role of carbon-based nanocatalysts in the hydrogenation of carbon dioxide and direct synthesis of dimethyl carbonate from carbon dioxide and methanol are reviewed. The current catalytic results obtained with different carbon-based nanocatalysts systems are presented and how these materials contribute to the carbon dioxide conversion is explained. In addition, different strategies and preparation methods of nanometallic catalysts on various carbon supports are described to optimize the dispersion of metal nanoparticles and catalytic activity. PMID:23901504

  14. Erosion of soil organic carbon: implications for carbon sequestration

    Science.gov (United States)

    Van Oost, Kristof; Van Hemelryck, Hendrik; Harden, Jennifer W.

    2009-01-01

    Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.

  15. Carbon dioxide dangers demonstration model

    Science.gov (United States)

    Venezky, Dina; Wessells, Stephen

    2010-01-01

    Carbon dioxide is a dangerous volcanic gas. When carbon dioxide seeps from the ground, it normally mixes with the air and dissipates rapidly. However, because carbon dioxide gas is heavier than air, it can collect in snowbanks, depressions, and poorly ventilated enclosures posing a potential danger to people and other living things. In this experiment we show how carbon dioxide gas displaces oxygen as it collects in low-lying areas. When carbon dioxide, created by mixing vinegar and baking soda, is added to a bowl with candles of different heights, the flames are extinguished as if by magic.

  16. Carbon Nanotube Biosensors

    Directory of Open Access Journals (Sweden)

    Carmen-Mihaela eTilmaciu

    2015-10-01

    Full Text Available Nanomaterials possess unique features which make them particularly attractive for biosensing applications. In particular Carbon Nanotubes (CNTs can serve as scaffolds for immobilization of biomolecules at their surface, and combine several exceptional physical, chemical, electrical and optical characteristics properties which make them one of the best suited materials for the transduction of signals associated with the recognition of analytes, metabolites or disease biomarkers. Here we provide a comprehensive review on these carbon nanostructures, in which we will describe their structural and physical properties, discuss functionalization and cellular uptake, biocompatibility and toxicity issues. We further review historical developments in the field of biosensors, and describe the different types of biosensors which have been developed over time, with specific focus on CNT-conjugates engineered for biosensing applications, and in particular detection of cancer biomarkers.

  17. Carbon Fiber Composites

    Science.gov (United States)

    1997-01-01

    HyComp(R), Inc. development a line of high temperature carbon fiber composite products to solve wear problems in the harsh environment of steel and aluminum mills. WearComp(R), self-lubricating composite wear liners and bushings, combines carbon graphite fibers with a polyimide binder. The binder, in conjunction with the fibers, provides the slippery surface, one that demands no lubrication, yet wears at a very slow rate. WearComp(R) typically lasts six to ten times longer than aluminum bronze. Unlike bronze, WearComp polishes the same surface and imparts a self-lube film for years of service. It is designed for continuous operation at temperatures of 550 degrees Fahrenheit and can operate under high compressive loads.

  18. Growing carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Yoshinori Ando

    2004-10-01

    Full Text Available The discovery of ‘fullerenes’ added a new dimension to the knowledge of carbon science1; and the subsequent discovery of ‘carbon nanotubes’ (CNTs, the elongated fullerene added a new dimension to the knowledge of technology2;. Today, ‘nanotechnology’ is a hot topic attracting scientists, industrialists, journalists, governments, and even the general public. Nanotechnology is the creation of functional materials, devices, and systems through control of matter on the nanometer scale and the exploitation of novel phenomena and properties of matter (physical, chemical, biological, electrical, etc. at that length scale. CNTs are supposed to be a key component of nanotechnology. Almost every week a new potential application of CNTs is identified, stimulating scientists to peep into this tiny tube with ever increasing curiosity.

  19. Carbon materials for supercapacitors

    Science.gov (United States)

    Gao, Yang

    As an important energy storage device, electrochemical supercapacitors or ultracapacitors fill the gap between conventional dielectric capacitors and batteries in terms of specific energy and power. Although supercapacitors have been used in electric vehicles, digital communication instruments, and pulsed lasers, further improvement of supercapacitor performance is highly needed to enhance the energy density without significantly losing the power density. Additionally, the conventional supercapacitors use rigid packages and liquid electrolytes, which limit applications in transparent and flexible electronics. To address these challenges, the research efforts in this dissertation mainly focused on: 1) improvement of the energy density of carbon nanoonions by chemical activation; 2) laser-assisted activation of carbon nanotubes for improved energy density; 3) fabrication of flexible solid-state supercapacitors based on nanocarbon and manganese dioxide (MnO2) hybrid electrodes; and 4) investigation of the electrochemical performance of graphene as transparent and flexible supercapacitor electrodes.

  20. Applications of Carbon Nanotubes

    Science.gov (United States)

    Ajayan, Pulickel M.; Zhou, Otto Z.

    Carbon nanotubes have attracted the fancy of many scientists worldwide. The small dimensions, strength and the remarkable physical properties of these structures make them a very unique material with a whole range of promising applications. In this review we describe some of the important materials science applications of carbon nanotubes. Specifically we discuss the electronic and electrochemical applications of nanotubes, nanotubes as mechanical reinforcements in high performance composites, nanotube-based field emitters, and their use as nanoprobes in metrology and biological and chemical investigations, and as templates for the creation of other nanostructures. Electronic properties and device applications of nanotubes are treated elsewhere in the book. The challenges that ensue in realizing some of these applications are also discussed from the point of view of manufacturing, processing, and cost considerations.

  1. Carbon neutron star atmospheres

    CERN Document Server

    Suleimanov, V F; Pavlov, G G; Werner, K

    2013-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in chemical composition of their atmospheres. For example, atmospheres of thermally - emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in CasA, a pure carbon atmosphere has recently been suggested by Ho & Heinke (2009). To test such a composition for other similar sources, a publicly available detailed grid of carbon model atmosphere spectra is needed. We have computed such a grid using the standard LTE approximation and assuming that the magnetic field does not exceed 10^8 G. The opacities and pressure ionization effects are calculated using the Opacity Project approach. We describe the properties of our models and investigate the impact of the adopted assumptions and approximations on the emergent spectra.

  2. Carbon Lorenz Curves

    Energy Technology Data Exchange (ETDEWEB)

    Groot, L. [Utrecht University, Utrecht School of Economics, Janskerkhof 12, 3512 BL Utrecht (Netherlands)

    2008-11-15

    The purpose of this paper is twofold. First, it exhibits that standard tools in the measurement of income inequality, such as the Lorenz curve and the Gini-index, can successfully be applied to the issues of inequality measurement of carbon emissions and the equity of abatement policies across countries. These tools allow policy-makers and the general public to grasp at a single glance the impact of conventional distribution rules such as equal caps or grandfathering, or more sophisticated ones, on the distribution of greenhouse gas emissions. Second, using the Samuelson rule for the optimal provision of a public good, the Pareto-optimal distribution of carbon emissions is compared with the distribution that follows if countries follow Nash-Cournot abatement strategies. It is shown that the Pareto-optimal distribution under the Samuelson rule can be approximated by the equal cap division, represented by the diagonal in the Lorenz curve diagram.

  3. Digital carbonate rock physics

    Science.gov (United States)

    Saenger, Erik H.; Vialle, Stephanie; Lebedev, Maxim; Uribe, David; Osorno, Maria; Duda, Mandy; Steeb, Holger

    2016-08-01

    Modern estimation of rock properties combines imaging with advanced numerical simulations, an approach known as digital rock physics (DRP). In this paper we suggest a specific segmentation procedure of X-ray micro-computed tomography data with two different resolutions in the µm range for two sets of carbonate rock samples. These carbonates were already characterized in detail in a previous laboratory study which we complement with nanoindentation experiments (for local elastic properties). In a first step a non-local mean filter is applied to the raw image data. We then apply different thresholds to identify pores and solid phases. Because of a non-neglectable amount of unresolved microporosity (micritic phase) we also define intermediate threshold values for distinct phases. Based on this segmentation we determine porosity-dependent values for effective P- and S-wave velocities as well as for the intrinsic permeability. For effective velocities we confirm an observed two-phase trend reported in another study using a different carbonate data set. As an upscaling approach we use this two-phase trend as an effective medium approach to estimate the porosity-dependent elastic properties of the micritic phase for the low-resolution images. The porosity measured in the laboratory is then used to predict the effective rock properties from the observed trends for a comparison with experimental data. The two-phase trend can be regarded as an upper bound for elastic properties; the use of the two-phase trend for low-resolution images led to a good estimate for a lower bound of effective elastic properties. Anisotropy is observed for some of the considered subvolumes, but seems to be insignificant for the analysed rocks at the DRP scale. Because of the complexity of carbonates we suggest using DRP as a complementary tool for rock characterization in addition to classical experimental methods.

  4. Carbon nanotube network varactor

    Science.gov (United States)

    Generalov, A. A.; Anoshkin, I. V.; Erdmanis, M.; Lioubtchenko, D. V.; Ovchinnikov, V.; Nasibulin, A. G.; Räisänen, A. V.

    2015-01-01

    Microelectromechanical system (MEMS) varactors based on a freestanding layer of single-walled carbon nanotube (SWCNT) films were designed, fabricated and tested. The freestanding SWCNT film was employed as a movable upper patch in the parallel plate capacitor of the MEMS. The measurements of the SWCNT varactors show very high tunability, nearly 100%, of the capacitance with a low actuation voltage of 10 V. The functionality of the varactor is improved by implementing a flexible nanocellulose aerogel filling.

  5. CARBON DIOXIDE FIXATION.

    Energy Technology Data Exchange (ETDEWEB)

    FUJITA,E.

    2000-01-12

    Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

  6. Accounting for carbon

    OpenAIRE

    Lovell, Heather; Sales de Aguiar, Thereza; Bebbington, Jan; Larrinaga-Gonzalez, Carlos; International Emissions Trading Association

    2010-01-01

    ACCA working in partnership with IETA This report reveals how large emitters in the European Emissions Trading Scheme (EU ETS) are accounting for emission allowances. The diversity of emission-allowance accounting practices being used in Europe shows carbon financial accounting to be in its formative stages - rules and practices are still unsettled. With this report, ACCA, in partnership with IETA, is opening up the debate to a wider international audience. Publisher PDF

  7. Improving Carbon Fixation Pathways

    OpenAIRE

    Ducat, Daniel C.; Silver, Pamela A

    2012-01-01

    A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing...

  8. Amorphous carbon for photovoltaics

    Science.gov (United States)

    Risplendi, Francesca; Grossman, Jeffrey C.

    2015-03-01

    All-carbon solar cells have attracted attention as candidates for innovative photovoltaic devices. Carbon-based materials such as graphene, carbon nanotubes (CNT) and amorphous carbon (aC) have the potential to present physical properties comparable to those of silicon-based materials with advantages such as low cost and higher thermal stability.In particular a-C structures are promising systems in which both sp2 and sp3 hybridization coordination are present in different proportions depending on the specific density, providing the possibility of tuning their optoelectronic properties and achieving comparable sunlight absorption to aSi. In this work we employ density functional theory to design suitable device architectures, such as bulk heterojunctions (BHJ) or pn junctions, consisting of a-C as the active layer material.Regarding BHJ, we study interfaces between aC and C nanostructures (such as CNT and fullerene) to relate their optoelectronic properties to the stoichiometry of aC. We demonstrate that the energy alignment between the a-C mobility edges and the occupied and unoccupied states of the CNT or C60 can be widely tuned by varying the aC density to obtain a type II interface.To employ aC in pn junctions we analyze the p- and n-type doping of a-C focusingon an evaluation of the Fermi level and work function dependence on doping.Our results highlight promising features of aC as the active layer material of thin-film solar cells.

  9. Nongovernmental valorization of carbon dioxide

    International Nuclear Information System (INIS)

    Carbon dioxide (CO2) is considered the largest contributor to the greenhouse gas effect. Most attempts to manage the flow of CO2 or carbon into our environment involve reducing net emissions or sequestering the gas into long-lived sinks. Using CO2 as a chemical feedstock has a long history, but using it on scales that might impact the net emissions of CO2 into the atmosphere has not generally been considered seriously. There is also a growing interest in employing our natural biomes of carbon such as trees, vegetation, and soils as storage media. Some amelioration of the net carbon emissions into the atmosphere could be achieved by concomitant large withdrawals of carbon. This report surveys the potential and limitations in employing carbon as a resource for organic chemicals, fuels, inorganic materials, and in using the biome to manage carbon. The outlook for each of these opportunities is also described

  10. A Better Carbon Footprint Label

    DEFF Research Database (Denmark)

    Thøgersen, John; Nielsen, Kristian S.

    2016-01-01

    Based on insights from behavioral economics, it is suggested to extend carbon footprint labeling with information about relative performance, using the well-known “traffic light” color scheme to communicate relative performance. To test this proposition, the impact of a carbon footprint label......, participants saw the original Carbon Trust label and in the other condition they saw the same label, but with traffic light colors added to communicate the product's relative performance in terms of carbon footprint. All included attributes were found to have a significant impact on consumer choices...... to indicate relative carbon footprint significantly increases carbon label effectiveness. Hence, a carbon footprint label is more effective if it uses traffic light colors to communicate the product's relative performance....

  11. Increasing the Tensile Property of Unidirectional Carbon/Carbon Composites by Grafting Carbon Nanotubes onto Carbon Fibers by Electrophoretic Deposition

    Institute of Scientific and Technical Information of China (English)

    Qiang Song; Kezhi Li; Hejun Li; Qiangang Fu

    2013-01-01

    Although in-situ growing carbon nanotubes (CNTs) on carbon fibers could greatly increase the matrix-dominated mechanical properties of carbon/carbon composites (C/Cs),it always decreased the tensile strength of carbon fibers.In this work,CNTs were introduced into unidirectional carbon fiber (CF) preforms by electrophoretic deposition (EPD) and they were used to reinforce C/Cs.Effects of the content of CNTs introduced by EPD on tensile property of unidirectional C/Cs were investigated.Results demonstrated that EPD could be used as a simple and efficient method to fabricate carbon nanotube reinforced C/Cs (CNT-C/Cs) with excellent tensile strength,which pays a meaningful way to maximize the global performance of CNT-C/Cs.

  12. Carbon taxes and India

    Energy Technology Data Exchange (ETDEWEB)

    Fisher-Vanden, K.A.; Pitcher, H.M.; Edmonds, J.A.; Kim, S.H. [Pacific Northwest Lab., Richland, WA (United States); Shukla, P.R. [Indian Institute of Management, Ahmedabad (India)

    1994-07-01

    Using the Indian module of the Second Generation Model 9SGM, we explore a reference case and three scenarios in which greenhouse gas emissions were controlled. Two alternative policy instruments (carbon taxes and tradable permits) were analyzed to determine comparative costs of stabilizing emissions at (1) 1990 levels (the 1 X case), (2) two times the 1990 levels (the 2X case), and (3) three times the 1990 levels (the 3X case). The analysis takes into account India`s rapidly growing population and the abundance of coal and biomass relative to other fuels. We also explore the impacts of a global tradable permits market to stabilize global carbon emissions on the Indian economy under the following two emissions allowance allocation methods: (1) {open_quotes}Grandfathered emissions{close_quotes}: emissions allowances are allocated based on 1990 emissions. (2) {open_quotes}Equal per capita emissions{close_quotes}: emissions allowances are allocated based on share of global population. Tradable permits represent a lower cost method to stabilize Indian emissions than carbon taxes, i.e., global action would benefit India more than independent actions.

  13. Studies of Carbon Nanotubes

    Science.gov (United States)

    Caneba, Gerard T.

    2005-01-01

    The fellowship experience for this summer for 2004 pertains to carbon nanotube coatings for various space-related applications. They involve the following projects: (a) EMI protection films from HiPco-polymers, and (b) Thermal protection nanosilica materials. EMI protection films are targeted to be eventually applied onto casings of laptop computers. These coatings are composites of electrically-conductive SWNTs and compatible polymers. The substrate polymer will be polycarbonate, since computer housings are typically made of carbon composites of this type of polymer. A new experimental copolymer was used last year to generate electrically-conductive and thermal films with HiPco at 50/50 wt/wt composition. This will be one of the possible formulations. Reference films will be base polycarbonate and neat HiPco onto polycarbonate films. Other coating materials that will be tried will be based on HiPco composites with commercial enamels (polyurethane, acrylic, polyester), which could be compatible with the polycarbonate substrate. Nanosilica fibers are planned for possible use as thermal protection tiles on the shuttle orbiter. Right now, microscale silica is used. Going to the nanoscale will increase the surface-volume-per-unit-area of radiative heat dissipation. Nanoscale carbon fibers/nanotubes can be used as templates for the generation of nanosilica. A sol-gel operation is employed for this purpose.

  14. Hydropower's Biogenic Carbon Footprint.

    Science.gov (United States)

    Scherer, Laura; Pfister, Stephan

    2016-01-01

    Global warming is accelerating and the world urgently needs a shift to clean and renewable energy. Hydropower is currently the largest renewable source of electricity, but its contribution to climate change mitigation is not yet fully understood. Hydroelectric reservoirs are a source of biogenic greenhouse gases and in individual cases can reach the same emission rates as thermal power plants. Little is known about the severity of their emissions at the global scale. Here we show that the carbon footprint of hydropower is far higher than previously assumed, with a global average of 173 kg CO2 and 2.95 kg CH4 emitted per MWh of electricity produced. This results in a combined average carbon footprint of 273 kg CO2e/MWh when using the global warming potential over a time horizon of 100 years (GWP100). Nonetheless, this is still below that of fossil energy sources without the use of carbon capture and sequestration technologies. We identified the dams most promising for capturing methane for use as alternative energy source. The spread among the ~1500 hydropower plants analysed in this study is large and highlights the importance of case-by-case examinations. PMID:27626943

  15. Carbon Structure Hazard Control

    Science.gov (United States)

    Yoder, Tommy; Greene, Ben; Porter, Alan

    2015-01-01

    Carbon composite structures are widely used in virtually all advanced technology industries for a multitude of applications. The high strength-to-weight ratio and resistance to aggressive service environments make them highly desirable. Automotive, aerospace, and petroleum industries extensively use, and will continue to use, this enabling technology. As a result of this broad range of use, field and test personnel are increasingly exposed to hazards associated with these structures. No single published document exists to address the hazards and make recommendations for the hazard controls required for the different exposure possibilities from damaged structures including airborne fibers, fly, and dust. The potential for personnel exposure varies depending on the application or manipulation of the structure. The effect of exposure to carbon hazards is not limited to personnel, protection of electronics and mechanical equipment must be considered as well. The various exposure opportunities defined in this document include pre-manufacturing fly and dust, the cured structure, manufacturing/machining, post-event cleanup, and post-event test and/or evaluation. Hazard control is defined as it is applicable or applied for the specific exposure opportunity. The carbon exposure hazard includes fly, dust, fiber (cured/uncured), and matrix vapor/thermal decomposition products. By using the recommendations in this document, a high level of confidence can be assured for the protection of personnel and equipment.

  16. Carbon taxes and India

    International Nuclear Information System (INIS)

    Using the Indian module of the Second Generation Model 9SGM, we explore a reference case and three scenarios in which greenhouse gas emissions were controlled. Two alternative policy instruments (carbon taxes and tradable permits) were analyzed to determine comparative costs of stabilizing emissions at (1) 1990 levels (the 1 X case), (2) two times the 1990 levels (the 2X case), and (3) three times the 1990 levels (the 3X case). The analysis takes into account India's rapidly growing population and the abundance of coal and biomass relative to other fuels. We also explore the impacts of a global tradable permits market to stabilize global carbon emissions on the Indian economy under the following two emissions allowance allocation methods: (1) open-quotes Grandfathered emissionsclose quotes: emissions allowances are allocated based on 1990 emissions. (2) open-quotes Equal per capita emissionsclose quotes: emissions allowances are allocated based on share of global population. Tradable permits represent a lower cost method to stabilize Indian emissions than carbon taxes, i.e., global action would benefit India more than independent actions

  17. Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement

    Directory of Open Access Journals (Sweden)

    Mehran Tehrani

    2014-05-01

    Full Text Available Carbon nanofilament and nanotubes (CNTs have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD, in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures—from ethylene mixtures at 550 °C—on commercial polyacrylonitrile (PAN-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD technique was also utilized to grow multiwall CNTs (MWCNTs on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique.

  18. A carbon sink pathway increases carbon productivity in cyanobacteria.

    Science.gov (United States)

    Oliver, John W K; Atsumi, Shota

    2015-05-01

    The burning of fossil reserves, and subsequent release of carbon into the atmosphere is depleting the supply of carbon-based molecules used for synthetic materials including plastics, oils, medicines, and glues. To provide for future society, innovations are needed for the conversion of waste carbon (CO2) into organic carbon useful for materials. Chemical production directly from photosynthesis is a nascent technology, with great promise for capture of CO2 using sunlight. To improve low yields, it has been proposed that photosynthetic capacity can be increased by a relaxation of bottlenecks inherent to growth. The limits of carbon partitioning away from growth within the cell and the effect of partitioning on carbon fixation are not well known. Here we show that expressing genes in a pathway between carbon fixation and pyruvate increases partitioning to 2,3-butanediol (23BD) and leads to a 1.8-fold increase in total carbon yield in the cyanobacterium Synechococcus elongatus PCC 7942. Specific 2,3-butanediol production increases 2.4-fold. As partitioning increases beyond 30%, it leads to a steep decline in total carbon yield. The data suggests a local maximum for carbon partitioning from the Calvin Benson cycle that is scalable with light intensity.

  19. Coastal climate reflected in carbon-13/carbon-12 ratio of organic carbon in varved sediment from Santa Barbara basin

    OpenAIRE

    Schimmelmann, Arndt; Tegner, Mia J.

    1991-01-01

    A 1844-1987 time-series of carbon stable isotope ratios from dated sedimentary total organic carbon from the center of the Santa Barbara basin is compared with historical climate and oceanographic records. Carbon derived from carbon-13-depleted phytoplankton and carbon-13-enriched kelp appear responsible for a large part of the isotopic variance in sedimentary total organic carbon. El Niño/Southern Oscillation events are recorded by the isotopic response of marine organic carbon in sediments.

  20. Carbon footprinting : a classroom exercise

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, H.; Grimm, M. [Arizona State Univ., Tempe (United States). School of Architecture and Landscape Architecture, College of Design

    2009-07-01

    This paper reported on an ongoing initiative at Arizona State University (ASU) to reduce the carbon footprint of buildings on campus. The College of Design and the Global Institute of Sustainability created a graduate level class where students in the fields of architecture, building design, urban planning, and sustainability applied a methodology to determine and improve a building's carbon footprint. Launched in 2008, the project currently has 13 buildings and will be expanded up to 50 buildings by the end of 2009. ASU is initially committing to carbon reduction and eventual carbon neutrality. The project offers students an opportunity to view the impact of their daily behaviours in terms of energy consumption and carbon emissions. The carbon footprinting methodology was used in a classroom setting by graduate students at ASU College of Design and School of Sustainability to determine the carbon footprint of 3 campus buildings. The methodology included an energy consumption analysis of the existing building, the creation of an as-built energy model, and the study of carbon footprint improvement scenarios with the ultimate goal of achieving carbon neutrality. Each improvement scenario was analyzed to determine its effect on overall carbon footprint and annual energy consumption, including electricity and natural gas use. 6 refs., 10 tabs., 4 figs.

  1. Catalytic carbon deposition on 3-dimensional carbon fibre supports

    OpenAIRE

    Thornton, Matthew James

    2005-01-01

    Catalytic carbon deposition reactions, using methane, ethane or synthetic natural gas (1.8 vol. % propane, 6.7 vol. % ethane and balance methane) as the carbon-containing gas feedstock with or without the addition of hydrogen, have been investigated over nickel, cobalt and iron catalysts supported on 3-dimensional carbon fibre supports, using both a horizontal tube furnace and an isothermal, isobaric induction furnace. The transition metal catalysts were prepared by impregnating 3-dimens...

  2. Carbon black directed synthesis of ultrahigh mesoporous carbon aerogels

    OpenAIRE

    Macías, Carlos; Haro Remón, Marta; Rasines, Gloria; Parra Soto, José Bernardo; Ovín Ania, María Concepción

    2013-01-01

    [EN] A simple modification of the conventional sol–gel polymerization of resorcinol–formaldehyde mixtures allowed a facile preparation of ultrahigh mesoporous carbon gels. In the conventional synthesis the growth of the cluster polymer particles leading to the development of the porosity is controlled by the R/C ratio. In the presence of a carbon conductive additive, the polymerization of the reactants proceeded through the formation of less-branched polymer clusters resulting in carbon gels ...

  3. Caracterización físico-mecánica, térmica y morfológica de polímeros de redes interpenetradas con base en poliuretano obtenido a partir de aceite de ricino y almidón modificados/polimetilmetacrilato (PMMA Physico-mechanical, thermal and morphological Behaviour of simultaneous interpenetrating polymer networks based on polyurethane from modified castor oiland starch/poly(Methyl Methacrylate

    Directory of Open Access Journals (Sweden)

    Manuel F. Valero

    2011-01-01

    Full Text Available El aceite de ricino se modificó por transesterificación con pentaeritritol. Paralelamente, se utilizó la reacción de glucosilación con glicerol para dividir el almidón en unidades monosacáridos. El glucósido obtenido reaccionó por transesterificación con el aceite modificado por transesterificación con pentaeritritol. Se determinó el índice de hidroxilo de los poliol-glucósidos en función del contenido de pentaeritritol y almidón utilizados en la síntesis. Se sintetizaron redes interpenetradas de polímero de manera simultánea (SINs con diferentes relaciones en peso poliuretano/PMMA de 100/0, 90/10, 80/20, 70/30, 60/40 y 50/50. Para la síntesis de la red de poliuretano (PU se utilizaron los poliol-glucósidos y diisocianato de isoforona (IPDI o con una relación NCO/OH = 1 y para la síntesis de la red de polimetilmetacrilato (PMMA se utilizó peróxido de benzoílo como agente iniciador y dimetacrilato de etilenglicol como agente entrecruzante. Los SINs se caracterizaron por sus propiedades fisicomecánicas como resistencia al ataque químico, dureza, resistencia a la tensión y elongación de ruptura. La estabilidad térmica de los SINs se determinó usando análisis termogravimétrico (TGA. La morfología de superficie se determinó usando microscopia electrónica de barrido (SEM y mostró una morfología de dos fases para todos los SINs.Castor oil was modified by transesterification with pentaerithritol. In a parallel step, starch was divided into monosaccharide units by glycosylation in order to obtain products with high hydroxyl content. The values of hydroxyl index were measured according to the content of pentaerithritol and starch used in the synthesis. Novel simultaneous interpenetrating polymer networks (SINs of polyurethane (PU and poly(methyl methacrylate (PMMA in different weight ratios of 100/0, 90/10, 80/20, 70/30, 60/40 and 50/50 were prepared based on polyol-glucosides. The polyurethane network was created by

  4. Carbon-Carbon Turbocharger Housing Unit for Intermittent Combustion Engines

    Science.gov (United States)

    Northam, G. Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

    1998-01-01

    An improved, lightweight, turbine housing unit for an intermittent combustion reciprocating internal combustion engine turbocharger is prepared from a lay-up or molding of carbon-carbon composite materials in a single-piece or two-piece process. When compared to conventional steel or cast iron, the use of carbon-carbon composite materials in a turbine housing unit reduces the overall weight of the engine and reduces the heat energy loss used in the turbocharging process. This reduction in heat energy loss and weight reduction provides for more efficient engine operation.

  5. Carbon isotope anomalies in carbonates of the Karelian series

    Science.gov (United States)

    Iudovich, Ia. E.; Makarikhin, V. V.; Medvedev, P. V.; Sukhanov, N. V.

    1990-07-01

    Results are presented on carbon isotope distributions in carbonates of the Karelian complex. A highly anomalous isotopic composition was found in carbonate rocks aged from 2.6 to 1.9 b.y. In the stromatolitic carbonates of the Onega water table, delta-(C-13) reaches a value of +18 percent, while the shungite layer of the Zaonega horizon is characterized by a wide dispersion (from +7.9 to -11.8 percent). These data are in good agreement with the known geochemical boundary (about 2.2 b.y. ago) in the history of the earth.

  6. Designing carbon markets. Part I: Carbon markets in time

    International Nuclear Information System (INIS)

    This paper analyses the design of carbon markets in time (i.e., intertemporally). It is part of a twin set of papers that ask, starting from first principles, what an optimal global carbon market would look like by around 2030. Our focus is on firm-level cap-and-trade systems, although much of what we say would also apply to government-level trading and carbon offset schemes. We examine the 'first principles' of temporal design that would help to maximise flexibility and to minimise costs, including banking and borrowing and other mechanisms to provide greater carbon price predictability and credibility over time.

  7. Multiporous carbon allotropes transformed from symmetry-matched carbon nanotubes

    Science.gov (United States)

    Cai, Yingxiang; Wang, Hao; Xu, Shengliang; Hu, Yujie; Liu, Ning; Xu, Xuechun

    2016-06-01

    Carbon nanotubes (CNTs) with homogeneous diameters have been proven to transform into new carbon allotropes under pressure but no studies on the compression of inhomogeneous CNTs have been reported. In this study, we propose to build new carbon allotropes from the bottom-up by applying pressure on symmetry-matched inhomogeneous CNTs. We find that the (3,0) CNT with point group C3v and the (6,0) CNT with point group C6v form an all sp3 hybridized hexagonal 3060-Carbon crystal, but the (4,0) CNT with point group D4h and the (8,0) CNT with point group D8h polymerize into a sp2+sp3 hybridized tetragonal 4080-Carbon structure. Their thermodynamic, mechanical and dynamic stabilities show that they are potential carbon allotropes to be experimentally synthesized. The multiporous structures, excellently mechanical properties and special electronic structures (semiconductive 3060-Carbon and semimetallic 4080-Carbon) imply their many potential applications, such as gases purification, hydrogen storage and lightweight semiconductor devices. In addition, we simulate their feature XRD patterns which are helpful for identifying the two carbon crystals in future experimental studies.

  8. Multiporous carbon allotropes transformed from symmetry-matched carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Yingxiang Cai

    2016-06-01

    Full Text Available Carbon nanotubes (CNTs with homogeneous diameters have been proven to transform into new carbon allotropes under pressure but no studies on the compression of inhomogeneous CNTs have been reported. In this study, we propose to build new carbon allotropes from the bottom-up by applying pressure on symmetry-matched inhomogeneous CNTs. We find that the (3,0 CNT with point group C3v and the (6,0 CNT with point group C6v form an all sp3 hybridized hexagonal 3060-Carbon crystal, but the (4,0 CNT with point group D4h and the (8,0 CNT with point group D8h polymerize into a sp2+sp3 hybridized tetragonal 4080-Carbon structure. Their thermodynamic, mechanical and dynamic stabilities show that they are potential carbon allotropes to be experimentally synthesized. The multiporous structures, excellently mechanical properties and special electronic structures (semiconductive 3060-Carbon and semimetallic 4080-Carbon imply their many potential applications, such as gases purification, hydrogen storage and lightweight semiconductor devices. In addition, we simulate their feature XRD patterns which are helpful for identifying the two carbon crystals in future experimental studies.

  9. Estudio Experimental de Piezas Lineales de Hormigón Reforzadas con Fibras de Carbono Experimental Study of Reinforced Concrete Beams Strengthened with Carbon Fibers

    Directory of Open Access Journals (Sweden)

    M. Valcuende

    2004-01-01

    Full Text Available Se ha estudiado el comportamiento de seis vigas reforzadas simultáneamente con láminas y tejidos de fibra de carbono. Se analiza, para este tipo de refuerzos, la validez de dos de los métodos de cálculo posiblemente más utilizados. En ambos métodos se plantean las ecuaciones de equilibrio de fuerzas y momentos, pero se introducen suposiciones diferentes: i el acero tiene suficiente capacidad plástica para no romperse y ii el agotamiento se produce siempre por rotura de la lámina. Los resultados obtenidos ponen de manifiesto que refuerzos de láminas y tejidos de fibra de carbono influyen notablemente sobre las piezas, mejorando su capacidad portante y modificando su comportamiento estructural en cuanto a rigidez y ductilidadA study on the behaviour of six beams reinforced with carbon fiber laminates and fabrics was done. The validity of the two most commonly used methods of evaluating the effects of these reinforcements was analyzed. Both methods propose equilibrium equations based on forces and moments, although introducing two different suppositions: i that the steel posesses enough elasticity to avoid breakage, and ii failure is always produced by the breakage of the laminate. The results obtained demonstrate that carbon fiber laminates and fabric reinforcements have notable influence on the pieces, improving their loading capacities and modifying their structural behavior regarding stiffness and ductility

  10. Global Carbon Budget 2015

    Science.gov (United States)

    Le Quéré, C.; Moriarty, R.; Andrew, R. M.; Canadell, J. G.; Sitch, S.; Korsbakken, J. I.; Friedlingstein, P.; Peters, G. P.; Andres, R. J.; Boden, T. A.; Houghton, R. A.; House, J. I.; Keeling, R. F.; Tans, P.; Arneth, A.; Bakker, D. C. E.; Barbero, L.; Bopp, L.; Chang, J.; Chevallier, F.; Chini, L. P.; Ciais, P.; Fader, M.; Feely, R. A.; Gkritzalis, T.; Harris, I.; Hauck, J.; Ilyina, T.; Jain, A. K.; Kato, E.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landschützer, P.; Lauvset, S. K.; Lefèvre, N.; Lenton, A.; Lima, I. D.; Metzl, N.; Millero, F.; Munro, D. R.; Murata, A.; Nabel, J. E. M. S.; Nakaoka, S.; Nojiri, Y.; O'Brien, K.; Olsen, A.; Ono, T.; Pérez, F. F.; Pfeil, B.; Pierrot, D.; Poulter, B.; Rehder, G.; Rödenbeck, C.; Saito, S.; Schuster, U.; Schwinger, J.; Séférian, R.; Steinhoff, T.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tilbrook, B.; van der Laan-Luijkx, I. T.; van der Werf, G. R.; van Heuven, S.; Vandemark, D.; Viovy, N.; Wiltshire, A.; Zaehle, S.; Zeng, N.

    2015-12-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and a methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates as well as consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuels and industry (EFF) are based on energy statistics and cement production data, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover-change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models forced by observed climate, CO2, and land-cover change (some including nitrogen-carbon interactions). We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ±1σ, reflecting the current capacity to characterise the annual estimates of each component of the global

  11. Global carbon budget 2014

    Science.gov (United States)

    Le Quéré, C.; Moriarty, R.; Andrew, R. M.; Peters, G. P.; Ciais, P.; Friedlingstein, P.; Jones, S. D.; Sitch, S.; Tans, P.; Arneth, A.; Boden, T. A.; Bopp, L.; Bozec, Y.; Canadell, J. G.; Chini, L. P.; Chevallier, F.; Cosca, C. E.; Harris, I.; Hoppema, M.; Houghton, R. A.; House, J. I.; Jain, A. K.; Johannessen, T.; Kato, E.; Keeling, R. F.; Kitidis, V.; Klein Goldewijk, K.; Koven, C.; Landa, C. S.; Landschützer, P.; Lenton, A.; Lima, I. D.; Marland, G.; Mathis, J. T.; Metzl, N.; Nojiri, Y.; Olsen, A.; Ono, T.; Peng, S.; Peters, W.; Pfeil, B.; Poulter, B.; Raupach, M. R.; Regnier, P.; Rödenbeck, C.; Saito, S.; Salisbury, J. E.; Schuster, U.; Schwinger, J.; Séférian, R.; Segschneider, J.; Steinhoff, T.; Stocker, B. D.; Sutton, A. J.; Takahashi, T.; Tilbrook, B.; van der Werf, G. R.; Viovy, N.; Wang, Y.-P.; Wanninkhof, R.; Wiltshire, A.; Zeng, N.

    2015-05-01

    Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and a methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates, consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil fuel combustion and cement production (EFF) are based on energy statistics and cement production data, respectively, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover-change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models forced by observed climate, CO2, and land-cover-change (some including nitrogen-carbon interactions). We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ±1σ, reflecting the current capacity to characterise the annual estimates of each

  12. Carbon Nanomaterials as Antibacterial Colloids

    Directory of Open Access Journals (Sweden)

    Michael Maas

    2016-07-01

    Full Text Available Carbon nanomaterials like graphene, carbon nanotubes, fullerenes and the various forms of diamond have attracted great attention for their vast potential regarding applications in electrical engineering and as biomaterials. The study of the antibacterial properties of carbon nanomaterials provides fundamental information on the possible toxicity and environmental impact of these materials. Furthermore, as a result of the increasing prevalence of resistant bacteria strains, the development of novel antibacterial materials is of great importance. This article reviews current research efforts on characterizing the antibacterial activity of carbon nanomaterials from the perspective of colloid and interface science. Building on these fundamental findings, recent functionalization strategies for enhancing the antibacterial effect of carbon nanomaterials are described. The review concludes with a comprehensive outlook that summarizes the most important discoveries and trends regarding antibacterial carbon nanomaterials.

  13. Compilation of carbon-14 data

    Energy Technology Data Exchange (ETDEWEB)

    Paasch, R.A.

    1985-07-08

    A review and critical analysis was made of the original sources of carbon-14 in the graphite moderator and reflector zones of the eight Hanford production reactors, the present physical and chemical state of the carbon-14, pathways (other than direct combustion) by which the carbon-14 could be released to the biosphere, and the maximum rate at which it might be released under circumstances which idealistically favor the release. Areas of uncertainty are noted and recommendations are made for obtaining additional data in three areas: (1) release rate of carbon-14 from irradiated graphite saturated with aerated water; (2) characterization of carbon-14 deposited outside the moderator and reflector zones; and (3) corrosion/release rate of carbon-14 from irradiated steel and aluminum alloys.

  14. Compilation of carbon-14 data

    International Nuclear Information System (INIS)

    A review and critical analysis was made of the original sources of carbon-14 in the graphite moderator and reflector zones of the eight Hanford production reactors, the present physical and chemical state of the carbon-14, pathways (other than direct combustion) by which the carbon-14 could be released to the biosphere, and the maximum rate at which it might be released under circumstances which idealistically favor the release. Areas of uncertainty are noted and recommendations are made for obtaining additional data in three areas: (1) release rate of carbon-14 from irradiated graphite saturated with aerated water; (2) characterization of carbon-14 deposited outside the moderator and reflector zones; and (3) corrosion/release rate of carbon-14 from irradiated steel and aluminum alloys

  15. Carbon Nanomaterials as Antibacterial Colloids

    OpenAIRE

    Michael Maas

    2016-01-01

    Carbon nanomaterials like graphene, carbon nanotubes, fullerenes and the various forms of diamond have attracted great attention for their vast potential regarding applications in electrical engineering and as biomaterials. The study of the antibacterial properties of carbon nanomaterials provides fundamental information on the possible toxicity and environmental impact of these materials. Furthermore, as a result of the increasing prevalence of resistant bacteria strains, the development of ...

  16. Metal incorporation into nanoporous carbon

    OpenAIRE

    Henley, SJ; Woolger, NEP; Carey, JD; Silva, SRP; Fuge, GM; Ashfold, MNR

    2005-01-01

    Nanoporous carbon films were deposited by 248 nm pulsed laser ablation of a graphite target in different background pressures of argon (P). The morphology changed from smooth, high-density amorphous carbon films at P = 20 mTorr to ultra-low density nanoporous material at P = 380 mTorr. Subsequently, the nanostructural, chemical and electrical properties of metal containing nanoporous carbon samples were investigated by ablating graphite targets containing known contents of Ni and Co. We demon...

  17. Recycling of carbon fibre composites

    OpenAIRE

    Melendi-Espina, S.; Morris, C N; Turner, T.A.; Pickering, S. J.

    2016-01-01

    A clear case for carbon fibre recovery and reuse exists on environmental grounds due to the high cost and energy use of virgin fibre production. On a specific energy basis, carbon fibres can be recovered at around 10% of the energy required to manufacture virgin fibres but the scale of the recovery process can make a large difference to overall cost effectiveness. This study will describe the technical and economic challenges associated with the recycling of carbon fibres, the state of the ar...

  18. Carbon cycle: storage beneath mangroves

    OpenAIRE

    BOUILLON, S

    2011-01-01

    In the face of continued deforestation, the high carbon stocks in mangrove forests unveiled by Donato et al. provide a strong incentive to consider mangrove ecosystems as priority areas for conservation. Furthermore, these results highlight the need for scientists and funding agencies to address uncertainties regarding the fate of the carbon after land clearance. Only a handful of studies have quantified the loss of sediment carbon after mangrove clear-cutting – but all suggest that these los...

  19. Carbon Mineral Ecology: Predicting the Undiscovered Minerals of Carbon

    Science.gov (United States)

    Hazen, R. M.; Hummer, D. R.; Downs, R. T.; Hystad, G.; Golden, J.

    2015-12-01

    The diversity and distribution of Earth's minerals through deep time reflects key events in our planet's crustal evolution. Studies in mineral ecology exploit mineralogical databases to document diversity-distribution relationships of minerals, which reveal that all carbon-bearing minerals, as well as subsets containing C with O, H, Ca, or Na, conform to Large Number of Rare Events (LNRE) distributions. LNRE models facilitate prediction of total mineral diversity, and thus point to minerals that exist on Earth but have not yet been discovered and described. Our model predicts that at least 548 C minerals exist on Earth today, indicating that at least 145 carbon-bearing mineral species have yet to be discovered. Furthermore, by analyzing subsets of the most common additional elements in carbon-bearing minerals (i.e., 378 C + O species; 282 C + H species; 133 C + Ca species; and 100 C + Na species), we predict that 129 of these missing carbon minerals contain oxygen, 118 contain hydrogen, 52 contain calcium, and more than 60 contain sodium. The majority of these as yet undescribed minerals are predicted to be hydrous carbonates, many of which may have been overlooked because they are colorless, poorly crystalized, and/or water-soluble. We propose the identities of plausible as yet undescribed carbon minerals, as well as search strategies for their discovery. Some of these minerals will be natural examples of known synthetic compounds, including carbides such as calcium carbide (CaC2), crystalline hydrocarbons such as pyrene (C16H10), and numerous oxalates, anhydrous carbonates, and hydrous carbonates. Many other missing carbon minerals will be isomorphs of known carbon minerals, notably of the more than 100 different hydrous carbonate structures. An understanding of Earth's "missing" minerals provides a more complete picture of geochemical processes that influence crustal evolution.

  20. Multimetallic Electrodeposition on Carbon Fibers

    Science.gov (United States)

    Böttger-Hiller, F.; Kleiber, J.; Böttger, T.; Lampke, T.

    2016-03-01

    Efficient lightweight design requires intelligent materials that meet versatile functions. One approach is to extend the range of properties of carbon fiber reinforced plastics (CFRP) by plating the fiber component. Electroplating leads to metalized layers on carbon fibers. Herein only cyanide-free electrolytes where used. Until now dendrite-free layers were only obtained using current densities below 1.0 A dm-2. In this work, dendrite-free tin and copper coatings were achieved by pre-metalizing the carbon fiber substrates. Furthermore, applying a combination of two metals with different sized thermal expansion coefficient lead to a bimetallic coating on carbon fiber rovings, which show an actuatory effect.

  1. Carbon in Atmospheric Particulate Matter

    International Nuclear Information System (INIS)

    Carbon compounds account for a large fraction of airborne particulate matter ('carbonaceous aerosols'). Their presence raises a number of scientific questions dealing with climate issues and possible effects on human health. This review describes the current state of knowledge with respect to the ambient concentrations levels (elemental carbon, organic carbon and organic matter) and the various emission sources, and summarizes the role of atmospheric carbon in the various environmental issues. The report finishes by identifying the actual gaps in knowledge and gives (related) suggestions for future research

  2. Carbon nanotube IR detectors (SV)

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, F. L.

    2012-03-01

    Sandia National Laboratories (Sandia) and Lockheed Martin Corporation (LMC) collaborated to (1) evaluate the potential of carbon nanotubes as channels in infrared (IR) photodetectors; (2) assemble and characterize carbon nanotube electronic devices and measure the photocurrent generated when exposed to infrared light;(3) compare the performance of the carbon nanotube devices with that of traditional devices; and (4) develop and numerically implement models of electronic transport and opto-electronic behavior of carbon nanotube infrared detectors. This work established a new paradigm for photodetectors.

  3. [Carbon monoxide poisoning].

    Science.gov (United States)

    Jaeger, K; Ruschulte, H; Heine, J; Piepenbrock, S

    2000-01-01

    Carbon monoxide (CO) is a product of incomplete burning of coals and carbon compounds and is a gas without any typical taste, colour or smell. Defective radiators or gas pipes, open fireplaces, fires and explosions are sources of unintended CO production and inhalation. CO bonds with haemoglobin much more readily than oxygen does. CO toxicity causes impaired oxygen delivery and utilisation at cellular level. It affects different sites within the body, but has its most profound impact on the organs with the highest oxygen requirement. CO concentration and the intensity and duration of inhalation determine the extent of intoxication. Following basic life support, assisted or controlled ventilation with 100% oxygen is essential during emergency care. Hyperbaric oxygenation (HBO) is the preferred therapeutic option for releasing CO from its binding to haemoglobin. It has been shown that CO may cause lipid peroxidation and leukocyte-mediated inflammatory changes in the brain, a process that may be inhibited by HBO. Patients with neurological symptoms including loss of consciousness and expectant mothers should undergo HBO treatment, no matter how high their CO levels are. Neonates and in-utero fetuses are more vulnerable due to the natural leftward shift of the dissociation curve of fetal haemoglobin, a lower baseline pO2 and carboxyhaemoglobin levels at equilibration that are 10-15% higher than maternal levels. Physicians need to be aware of the potential occurrence of this life threatening hazard so that appropriate emergency treatment can be administered and fatalities prevented. PMID:10920484

  4. Carbon nanotube computer.

    Science.gov (United States)

    Shulaker, Max M; Hills, Gage; Patil, Nishant; Wei, Hai; Chen, Hong-Yu; Wong, H-S Philip; Mitra, Subhasish

    2013-09-26

    The miniaturization of electronic devices has been the principal driving force behind the semiconductor industry, and has brought about major improvements in computational power and energy efficiency. Although advances with silicon-based electronics continue to be made, alternative technologies are being explored. Digital circuits based on transistors fabricated from carbon nanotubes (CNTs) have the potential to outperform silicon by improving the energy-delay product, a metric of energy efficiency, by more than an order of magnitude. Hence, CNTs are an exciting complement to existing semiconductor technologies. Owing to substantial fundamental imperfections inherent in CNTs, however, only very basic circuit blocks have been demonstrated. Here we show how these imperfections can be overcome, and demonstrate the first computer built entirely using CNT-based transistors. The CNT computer runs an operating system that is capable of multitasking: as a demonstration, we perform counting and integer-sorting simultaneously. In addition, we implement 20 different instructions from the commercial MIPS instruction set to demonstrate the generality of our CNT computer. This experimental demonstration is the most complex carbon-based electronic system yet realized. It is a considerable advance because CNTs are prominent among a variety of emerging technologies that are being considered for the next generation of highly energy-efficient electronic systems.

  5. Carbon dioxide and climate

    Energy Technology Data Exchange (ETDEWEB)

    1990-10-01

    Scientific and public interest in greenhouse gases, climate warming, and global change virtually exploded in 1988. The Department's focused research on atmospheric CO{sub 2} contributed sound and timely scientific information to the many questions produced by the groundswell of interest and concern. Research projects summarized in this document provided the data base that made timely responses possible, and the contributions from participating scientists are genuinely appreciated. In the past year, the core CO{sub 2} research has continued to improve the scientific knowledge needed to project future atmospheric CO{sub 2} concentrations, to estimate climate sensitivity, and to assess the responses of vegetation to rising concentrations of CO{sub 2} and to climate change. The Carbon Dioxide Research Program's goal is to develop sound scientific information for policy formulation and governmental action in response to changes of atmospheric CO{sub 2}. The Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1990 and gives a brief overview of objectives, organization, and accomplishments.

  6. Smart photonic carbon brush

    Science.gov (United States)

    Morozov, Oleg G.; Kuznetsov, Artem A.; Morozov, Gennady A.; Nureev, Ilnur I.; Sakhabutdinov, Airat Z.; Faskhutdinov, Lenar M.; Artemev, Vadim I.

    2016-03-01

    Aspects of the paper relate to a wear monitoring system for smart photonic carbon brush. There are many applications in which regular inspection is not feasible because of a number of factors including, for example, time, labor, cost and disruptions due to down time. Thus, there is a need for a system that can monitor the wear of a component while the component is in operation or without having to remove the component from its operational position. We propose a new smart photonic method for characterization of carbon brush wear. It is based on the usage of advantages of the multiplicative response of FBG and LPFG sensors and its double-frequency probing. Additional measuring parameters are the wear rate, the brush temperature, the engine rotation speed, the hangs control, and rotor speed. Sensor is embedded in brush. Firstly the change of sensor length is used to measure wear value and its central wavelength shift for temperature ones. The results of modeling and experiments are presented.

  7. Carbon Nanotube Purification

    Science.gov (United States)

    Delzeit, Lance D. (Inventor); Delzeit, Clement J. (Inventor)

    2005-01-01

    A method for cleaning or otherwise removing amorphous carbon and other residues that arise in growth of a carbon nanotube (CNT) array. The CNT array is exposed to a plurality of hydroxyls or hydrogen, produced from a selected vapor or liquid source such as H2O or H2O2. and the hydroxyls or hydrogen (neutral or electrically charged) react with the residues to produce partly or fully dissolved or hydrogenated or hydroxylizated products that can be removed or separated from the CNT array. The hydroxyls or hydrogen can be produced by heating the CNT array, residue and selected vapor or liquid source or by application of an electromagnetic excitation signal with a selected frequency or range of frequencies to dissociate the selected vapor or liquid. The excitation frequency can be chirped to cover a selected range of frequencies corresponding to dissociation of the selected vapor or liquid. Sonication may be uscd to supplement dissociation of the H2O and/or H2O2.

  8. Double-walled carbon nanotubes synthesized using carbon black as the dot carbon source

    Science.gov (United States)

    Chen, Zhi-Gang; Li, Feng; Ren, Wen-Cai; Cong, Hongtao; Liu, Chang; Qing Lu, Gao; Cheng, Hui-Ming

    2006-07-01

    Double-walled carbon nanotubes (DWNTs) were synthesized used carbon black as the dot carbon source by a semi-continuous hydrogen arc discharge process. High-resolution transmission electron microscopy (HRTEM) observations revealed that most of the tubes were DWNTs with outer and inner diameters in the range of 2.67-4 nm and 1.96-3.21 nm, respectively. Most of the DWNTs were in a bundle form of about 10-30 nm in diameter with high purity (about 70%) from thermal gravimetric analysis (TGA), resonant laser Raman spectroscopy, scanning electron microscopy (SEM) and TEM characterizations. It was found that carbon black as the dot carbon source could be easy controlled to synthesize one type of nanotube. A simple process combining oxidation and acid treatment to purify the DWNT bundles was used without damaging the bundles. The structure of carbon black, as the key element for influencing purity, bundle formation and purification of DWNTs, is discussed.

  9. Studies of activated carbon and carbon black for supercapacitor applications

    Energy Technology Data Exchange (ETDEWEB)

    Richner, R.; Mueller, S.; Koetz, R.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Carbon Black and activated carbon materials providing high surface areas and a distinct pore distribution are prime materials for supercapacitor applications at frequencies < 0.5 Hz. A number of these materials were tested for their specific capacitance, surface and pore size distribution. High capacitance electrodes were manufactured on the laboratory scale with attention to ease of processability. (author) 1 fig., 1 ref.

  10. Carbon-Carbon High Melt Coating for Nozzle Extensions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The High Melt Coating system is applied to a carbon-carbon structure and embeds HfC, ZrB2 in the outer layers. ACC High Melt builds on the time tested base material...

  11. Carbon dioxide sequestration in cement kiln dust through mineral carbonation.

    Science.gov (United States)

    Huntzinger, Deborah N; Gierke, John S; Kawatra, S Komar; Eisele, Timothy C; Sutter, Lawrence L

    2009-03-15

    Carbon sequestration through the formation of carbonates is a potential means to reduce CO2 emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation The degree of mineral carbonation achievable in cement kiln dust (CKD) underambienttemperatures and pressures was examined through a series of batch and column experiments. The overall extent and potential mechanisms and rate behavior of the carbonation process were assessed through a complementary set of analytical and empirical methods, including mass change, thermal analysis, and X-ray diffraction. The carbonation reactions were carried out primarily through the reaction of CO2 with Ca(OH)2, and CaCO3 was observed as the predominant carbonation product. A sequestration extent of over 60% was observed within 8 h of reaction without any modifications to the waste. Sequestration appears to follow unreacted core model theory where reaction kinetics are controlled by a first-order rate constant at early times; however, as carbonation progresses, the kinetics of the reaction are attenuated by the extent of the reaction due to diffusion control, with the extent of conversion never reaching completion. PMID:19368202

  12. High-Melt Carbon-Carbon Coating for Nozzle Extensions

    Science.gov (United States)

    Thompson, James

    2015-01-01

    Carbon-Carbon Advanced Technologies, Inc. (C-CAT), has developed a high-melt coating for use in nozzle extensions in next-generation spacecraft. The coating is composed primarily of carbon-carbon, a carbon-fiber and carbon-matrix composite material that has gained a spaceworthy reputation due to its ability to withstand ultrahigh temperatures. C-CAT's high-melt coating embeds hafnium carbide (HfC) and zirconium diboride (ZrB2) within the outer layers of a carbon-carbon structure. The coating demonstrated enhanced high-temperature durability and suffered no erosion during a test in NASA's Arc Jet Complex. (Test parameters: stagnation heat flux=198 BTD/sq ft-sec; pressure=.265 atm; temperature=3,100 F; four cycles totaling 28 minutes) In Phase I of the project, C-CAT successfully demonstrated large-scale manufacturability with a 40-inch cylinder representing the end of a nozzle extension and a 16-inch flanged cylinder representing the attach flange of a nozzle extension. These demonstrators were manufactured without spalling or delaminations. In Phase II, C-CAT worked with engine designers to develop a nozzle extension stub skirt interfaced with an Aerojet Rocketdyne RL10 engine. All objectives for Phase II were successfully met. Additional nonengine applications for the coating include thermal protection systems (TPS) for next-generation spacecraft and hypersonic aircraft.

  13. Biological Carbon Sequestration and Carbon Trading Re-Visited

    NARCIS (Netherlands)

    Kooten, van G.C.

    2009-01-01

    Biological activities that sequester carbon create CO2 offset credits that could obviate the need for reductions in fossil fuel use. Credits are earned by storing carbon in terrestrial ecosystems and wood products, although CO2 emissions are also mitigated by delaying deforestation, which accounts f

  14. Intermediate Temperature Carbon - Carbon Composite Structures. CRADA Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lara-Curzio, Edgar [ORNL

    2007-06-01

    The objective of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC (the "Contractor") and Synterials, Inc. (the "Participant") was to demonstrate promising processing methods, which can lead to producing Carbon-Carbon Composites (CCC), with tensile and interlaminar properties comparable to those of organic matrix composites and environmental stability at 1200 F for long periods of time. The participant synthesized carbon-carbon composites with two different fiber coatings and three different matrices. Both parties evaluated the tensile and interlaminar properties of these materials and characterized the microstructure of the matrices and interfaces. It was found that fiber coatings of carbon and boron carbide provided the best environmental protection and resulted in composites with high tensile strength.

  15. Growth of carbon nanotubes on carbon fibers without strength degradation

    Energy Technology Data Exchange (ETDEWEB)

    De Greef, Niels [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium); Magrez, Arnaud; Forro, Laszlo [Institute of Condensed Matter Physics, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland); Couteau, Edina; Locquet, Jean-Pierre [Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee (Belgium); Seo, Jin Won [Department of Metallurgy and Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium); Institute of Condensed Matter Physics, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

    2012-12-15

    Carbon nanotubes (CNTs) are grown on PAN-based carbon fibers by means of catalytic chemical vapor deposition technique. By using catalytic thermal decomposition of hydrocarbon, CNTs can be grown in the temperature range of 650-750 C. However, carbon fibers suffer significant damages resulting in decrease of initial tensile strength. By applying the oxidative dehydrogenation reaction of C{sub 2}H{sub 2} with CO{sub 2}, we found an alternative way to grow CNTs on carbon fibers at low temperatures, such as 500 C. Scanning electron microscope results combined with single fiber tests indicate that this low temperature growth enables homogeneous grafting of CNTs onto carbon fibers without degradation of tensile strength. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Prospects for using carbon-carbon composites for EMI shielding

    Science.gov (United States)

    Gaier, James R.

    1990-01-01

    Since pyrolyzed carbon has a higher electrical conductivity than most polymers, carbon-carbon composites would be expected to have higher electromagnetic interference (EMI) shielding ability than polymeric resin composites. A rule of mixtures model of composite conductivity was used to calculate the effect on EMI shielding of substituting a pyrolyzed carbon matrix for a polymeric matrix. It was found that the improvements were small, no more than about 2 percent for the lowest conductivity fibers (ex-rayon) and less than 0.2 percent for the highest conductivity fibers (vapor grown carbon fibers). The structure of the rule of mixtures is such that the matrix conductivity would only be important in those cases where it is much higher than the fiber conductivity, as in metal matrix composites.

  17. Carbonate Looping for De-Carbonization of Cement Plants

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Andersen, Maria Friberg; Lin, Weigang;

    2011-01-01

    feasible technology is to be developed. The carbonate looping process is a promising technology, which is particularly suitable for the cement industry as limestone could be used for capture and release of CO2. Integration of carbonate looping process into cement pyroprocess has two advantages: 1......) to capture emitted CO2 and 2) to generate power for internal use, because high quality energy can be recovered from carbonate looping which is operated at high temperature unlike amine process. A simple carbonate looping process model was developed based on average conversion of calcined limestone defined...... on the calciner capacity is also investigated. The results from this simple model show the importance of cement industry to the carbon capture technology for its application to power plants....

  18. The kinetics of binding carbon dioxide in magnesium carbonate

    Energy Technology Data Exchange (ETDEWEB)

    Butt, D.P.; Lackner, K.S.; Wendt, C.H.; Vaidya, R.; Pile, D.L.; Park, Y.; Holesinger, T.; Harradine, D.M. [Los Alamos National Lab., NM (United States); Nomura, Koji [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.]|[Chichibu Onada Cement Co., Tokyo (Japan)

    1998-08-01

    Humans currently consume about 6 Gigatons of carbon annually as fossil fuel. In some sense, the coal industry has a unique advantage over many other anthropogenic and natural emitters of CO{sub 2} in that it owns large point sources of CO{sub 2} from which this gas could be isolated and disposed of. If the increased energy demands of a growing world population are to be satisfied from coal, the implementation of sequestration technologies will likely be unavoidable. The authors` method of sequestration involves binding carbon dioxide as magnesium carbonate, a thermodynamically stable solid, for safe and permanent disposal, with minimal environmental impact. The technology is based on extracting magnesium hydroxide from common ultramafic rock for thermal carbonation and subsequent disposition. The economics of the method appear to be promising, however, many details of the proposed process have yet to be optimized. Realization of a cost effective method requires development of optimal technologies for efficient extraction and thermal carbonation.

  19. Carbon-Carbon High Melt Coating for Nozzle and Nozzle Extensions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — C-CAT, which has proven carbon-carbon fabrication capabilities, will investigate use of ACC-6 High Melt oxidation protective system on carbon-carbon for use on the...

  20. Activated Carbon, Carbon Nanofiber and Carbon Nanotube Supported Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

    Directory of Open Access Journals (Sweden)

    Eduardo Santillan-Jimenez

    2015-03-01

    Full Text Available Molybdenum carbide was supported on three types of carbon support—activated carbon; multi-walled carbon nanotubes; and carbon nanofibers—using ammonium molybdate and molybdic acid as Mo precursors. The use of activated carbon as support afforded an X-ray amorphous Mo phase, whereas crystalline molybdenum carbide phases were obtained on carbon nanofibers and, in some cases, on carbon nanotubes. When the resulting catalysts were tested in the hydrodeoxygenation (HDO of guaiacol in dodecane, catechol and phenol were obtained as the main products, although in some instances significant amounts of cyclohexane were produced. The observation of catechol in all reaction mixtures suggests that guaiacol was converted into phenol via sequential demethylation and HDO, although the simultaneous occurrence of a direct demethoxylation pathway cannot be discounted. Catalysts based on carbon nanofibers generally afforded the highest yields of phenol; notably, the only crystalline phase detected in these samples was Mo2C or Mo2C-ζ, suggesting that crystalline Mo2C is particularly selective to phenol. At 350 °C, carbon nanofiber supported Mo2C afforded near quantitative guaiacol conversion, the selectivity to phenol approaching 50%. When guaiacol HDO was performed in the presence of acetic acid and furfural, guaiacol conversion decreased, although the selectivity to both catechol and phenol was increased.

  1. Carbon recycling in ophiolite-hosted carbonates, Oman-UAE

    Science.gov (United States)

    Stephen, A.; Jenkin, G. R.; Smith, D. J.; Styles, M. T.; Naden, J.; Boyce, A. J.; Bryant, C. L.

    2013-12-01

    Large-scale surface and subsurface freshwater carbonate deposits of probable Quaternary age have formed on the Oman-UAE ophiolite. Here, serpentinisation reactions in ultramafic rocks have produced calcite and magnesite. These carbonates are frequently cited as examples of natural atmospheric CO2 sequestration, but the possibility of carbon recycling has not been addressed. The aim of this study is to assess the degree of atmospheric CO2 being incorporated into carbonates versus that which has been recycled from alternative sources such as soil CO2, or limestones that underlie the ophiolite. This has been determined through δ13C/δ18O, 87Sr/86Sr and 14C analysis of all major carbonate lithofacies identified. Our analyses of modern carbonate crusts forming on the surface of stagnant hyperalkaline (pH >11) waters show highly depleted δ13C and δ18O values (-25.5‰ ×0.5 PDB and -16.8‰ ×0.5 PDB respectively). This depletion has been attributed to a kinetic isotope effect occurring during atmospheric CO2 exchange with Ca(OH)2 hyperalkaline waters [1]. By comparison, inactive travertine deposits show a large range in δ13C (-10.5 to -21.8‰ PDB) which lies on a trajectory from the composition of modern crusts towards bicarbonate fluids in equilibrium with soil CO2. We interpret this trend as being produced by the mixing of different carbon sources, either at the time of formation or during later alteration. Modern carbonates and inactive travertines also have 87Sr/86Sr ratios and Sr concentrations similar to Cretaceous and Tertiary limestones which surround the ophiolite, whilst subsurface veins also display 87Sr/86Sr ratios similar to these Cretaceous limestones. Carbon recycling can also be determined with 14C. Modern atmospheric CO2 has a global average of 105-106% modern 14C (pMC), therefore freshwater carbonates forming solely from atmospheric CO2 would be expected to contain >100 pMC. However, modern carbonates display varied results from 94.5-101.4 p

  2. Psychological effectiveness of carbon labelling

    Science.gov (United States)

    Beattie, Geoffrey

    2012-04-01

    Despite the decision by supermarket-giant Tesco to delay its plan to add carbon-footprint information onto all of its 70,000 products, carbon labelling, if carefully designed, could yet change consumer behaviour. However, it requires a new type of thinking about consumers and much additional work.

  3. Radiation Effects in Carbon Nanoelectronics

    Directory of Open Access Journals (Sweden)

    Cory D. Cress

    2012-07-01

    Full Text Available We experimentally investigate the effects of Co-60 irradiation on the electrical properties of single-walled carbon nanotube and graphene field-effect transistors. We observe significant differences in the radiation response of devices depending on their irradiation environment, and confirm that, under controlled conditions, standard dielectric hardening approaches are applicable to carbon nanoelectronics devices.

  4. Radiation Effects in Carbon Nanoelectronics

    OpenAIRE

    Cory D. Cress; McMorrow, Julian J.; Robinson, Jeremy T.; Landi, Brian J.; Seth M. Hubbard; Messenger, Scott R.

    2012-01-01

    We experimentally investigate the effects of Co-60 irradiation on the electrical properties of single-walled carbon nanotube and graphene field-effect transistors. We observe significant differences in the radiation response of devices depending on their irradiation environment, and confirm that, under controlled conditions, standard dielectric hardening approaches are applicable to carbon nanoelectronics devices.

  5. Quantum transport in carbon nanotubes

    NARCIS (Netherlands)

    Jarillo-Herrero, P.D.

    2005-01-01

    Electronic transport through nanostructures can be very different from trans- port in macroscopic conductors, especially at low temperatures. Carbon na- notubes are tiny cylinders made of carbon atoms. Their remarkable electronic and mechanical properties, together with their small size (a few nm in

  6. Carbon budgets in symbiotic associations

    Energy Technology Data Exchange (ETDEWEB)

    Muscatine, L.; Falkowski, P.G.; Dubinsky, Z.

    1983-01-01

    Methods are described which permit the estimation of daily budgets for photosynthetically fixed carbon in any alga-invertebrate symbiosis. Included is a method for estimating total daily translocation which does not involve the use of C-14. A daily carbon budget for a shallow water symbiotic reef coral is presented.

  7. Breaking Carbon Lock-in

    DEFF Research Database (Denmark)

    Driscoll, Patrick Arthur

    2014-01-01

    This central focus of this paper is to highlight the ways in which path dependencies and increasing returns (network effects) serve to reinforce carbon lock-in in large-scale road transportation infrastructure projects. Breaking carbon lock-in requires drastic changes in the way we plan future...

  8. The Carbon City Index (CCI)

    DEFF Research Database (Denmark)

    Boyd, Britta; Straatman, Bas; Mangalagiu, Diana;

    This paper presents a consumption-based Carbon City Index for CO2 emissions in a city. The index is derived from regional consumption and not from regional production. It includes imports and exports of emissions, factual emission developments, green investments as well as low carbon city...

  9. Allyl 4-hydroxyphenyl carbonate

    Directory of Open Access Journals (Sweden)

    Víctor Hugo Flores Ahuactzin

    2009-07-01

    Full Text Available The title molecule, C10H10O4, is a functionalized carbonate used in the synthetic route to organic glasses. The central CH fragment of the allyl group is disordered over two positions, with occupancies in a 0.758 (10:0.242 (10ratio. This disorder reflects the torsional flexibility of the oxygen–allyl group, although both disordered parts present the expected anticlinal conformation, with O—CH2—CH=CH2 torsion angles of −111 (2 and 119.1 (4°. The crystal structure is based on chains parallel to [010], formed by O...H—O hydrogen bonds involving hydroxyl and carbonyl groups as donors and acceptors, respectively. The molecular packing is further stabilized by two weak C—H...π contacts from the benzene ring of the asymmetric unit with two benzene rings of neighboring molecules.

  10. Forecasting carbon dioxide emissions.

    Science.gov (United States)

    Zhao, Xiaobing; Du, Ding

    2015-09-01

    This study extends the literature on forecasting carbon dioxide (CO2) emissions by applying the reduced-form econometrics approach of Schmalensee et al. (1998) to a more recent sample period, the post-1997 period. Using the post-1997 period is motivated by the observation that the strengthening pace of global climate policy may have been accelerated since 1997. Based on our parameter estimates, we project 25% reduction in CO2 emissions by 2050 according to an economic and population growth scenario that is more consistent with recent global trends. Our forecasts are conservative due to that we do not have sufficient data to fully take into account recent developments in the global economy.

  11. Total organic carbon analyzer

    Science.gov (United States)

    Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.

    1991-01-01

    The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

  12. Carbon Nanotube Electron Gun

    Science.gov (United States)

    Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

    2013-01-01

    An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

  13. Carbon emissions control strategies

    International Nuclear Information System (INIS)

    This study was undertaken to address a fundamental issue: the cost of slowing climate change. Experts in eight nations were asked to evaluate, using the best economic models available, the prospects for reducing fossil fuel-based carbon emissions in their respective nations. The nations selected as case studies include: the Soviet Union, Poland, the United States, Japan, Hungary, France, the United Kingdom, and Canada. As important contributors to the greenhouse effect, these industrialized nations must find ways to substantially reduce their emissions. This is especially critical given that developing nations' emissions are expected to rise in the coming decades in the search for economic development. Ten papers have been processed separately for inclusion in the appropriate data bases

  14. Carbon nanotube biconvex microcavities

    Science.gov (United States)

    Butt, Haider; Yetisen, Ali K.; Ahmed, Rajib; Yun, Seok Hyun; Dai, Qing

    2015-03-01

    Developing highly efficient microcavities with predictive narrow-band resonance frequencies using the least amount of material will allow the applications in nonlinear photonic devices. We have developed a microcavity array that comprised multi-walled carbon nanotubes (MWCNT) organized in a biconvex pattern. The finite element model allowed designing microcavity arrays with predictive transmission properties and assessing the effects of the microarray geometry. The microcavity array demonstrated negative index and produced high Q factors. 2-3 μm tall MWCNTs were patterned as biconvex microcavities, which were separated by 10 μm in an array. The microcavity was iridescent and had optical control over the diffracted elliptical patterns with a far-field pattern, whose properties were predicted by the model. It is anticipated that the MWCNT biconvex microcavities will have implications for the development of highly efficient lenses, metamaterial antennas, and photonic circuits.

  15. Carbon nanotube optical mirrors

    Science.gov (United States)

    Chen, Peter C.; Rabin, Douglas

    2015-01-01

    We report the fabrication of imaging quality optical mirrors with smooth surfaces using carbon nanotubes (CNT) embedded in an epoxy matrix. CNT/epoxy is a multifunctional composite material that has sensing capabilities and can be made to incorporate self-actuation. Moreover, as the precursor is a low density liquid, large and lightweight mirrors can be fabricated by processes such as replication, spincasting, and three-dimensional printing. Therefore, the technology holds promise for the development of a new generation of lightweight, compact "smart" telescope mirrors with figure sensing and active or adaptive figure control. We report on measurements made of optical and mechanical characteristics, active optics experiments, and numerical modeling. We discuss possible paths for future development.

  16. Forests as carbon sinks

    Energy Technology Data Exchange (ETDEWEB)

    Houghton, R.A.; Woodwell, R.M. [Woods Hole Research Center, Woods Hole, MA (United States)

    1995-11-01

    When the nations of the world signed and later ratified the United Nations Framework Convention on Climate Change (FCCC), they accepted the difficult challenge of stabilizing the composition of the atmosphere with respect to the greenhouse gases (GHGs). Success will require a reduction in both use of fossil fuels and rates of deforestation. Forests have a large enough influence on the atmosphere that one of the options for stabilizing the concentrations of GHGs in the atmosphere includes the use of forests as a carbon sink through reforestation of large areas. We identify in this paper the potential and the limitations of such projects. We discuss the implications of four approaches in management of forests globally: (i) continued deforestation, (ii) halting deforestation, (iii) net reforestation including agroforestry, and (iv) substituting the use of wood fuels for fossil fuels.

  17. Functionalization of Carbon Nanotubes

    Science.gov (United States)

    Khare, Bishun N. (Inventor); Meyyappan, Meyya (Inventor)

    2009-01-01

    Method and system for functionalizing a collection of carbon nanotubes (CNTs). A selected precursor gas (e.g., H2 or F2 or CnHm) is irradiated to provide a cold plasma of selected target species particles, such as atomic H or F, in a first chamber. The target species particles are d irected toward an array of CNTs located in a second chamber while suppressing transport of ultraviolet radiation to the second chamber. A CNT array is functionalized with the target species particles, at or below room temperature, to a point of saturation, in an exposure time interval no longer than about 30 sec. *Discrimination against non-target species is provided by (i) use of a target species having a lifetime that is much greater than a lifetime of a non-target species and/or (2) use of an applied magnetic field to discriminate between charged particle trajectories for target species and for non-target species.

  18. Carbon nanotube biconvex microcavities

    Energy Technology Data Exchange (ETDEWEB)

    Butt, Haider, E-mail: h.butt@bham.ac.uk; Ahmed, Rajib [Nanotechnology Laboratory, School of Mechanical Engineering, University of Birmingham, Birmingham B15 2TT (United Kingdom); Yetisen, Ali K.; Yun, Seok Hyun [Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts 02114 (United States); Dai, Qing [National Center for Nanoscience and Technology, Beijing 100190 (China)

    2015-03-23

    Developing highly efficient microcavities with predictive narrow-band resonance frequencies using the least amount of material will allow the applications in nonlinear photonic devices. We have developed a microcavity array that comprised multi-walled carbon nanotubes (MWCNT) organized in a biconvex pattern. The finite element model allowed designing microcavity arrays with predictive transmission properties and assessing the effects of the microarray geometry. The microcavity array demonstrated negative index and produced high Q factors. 2–3 μm tall MWCNTs were patterned as biconvex microcavities, which were separated by 10 μm in an array. The microcavity was iridescent and had optical control over the diffracted elliptical patterns with a far-field pattern, whose properties were predicted by the model. It is anticipated that the MWCNT biconvex microcavities will have implications for the development of highly efficient lenses, metamaterial antennas, and photonic circuits.

  19. 40 CFR 86.316-79 - Carbon monoxide and carbon dioxide analyzer specifications.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Carbon monoxide and carbon dioxide... Test Procedures § 86.316-79 Carbon monoxide and carbon dioxide analyzer specifications. (a) Carbon monoxide and carbon dioxide measurements are to be made with nondispersive infrared (NDIR) an analyzers....

  20. Adhesivos de poliuretano termoplásticos potencialmente biodegrables obtenidos con derivados de productos naturales

    OpenAIRE

    Carbonell Blasco, Pilar

    2013-01-01

    Los adhesivos de poliuretano se han empezado a usar en medicina. Además, en la actualidad debido al desarrollo de la química verde se busca la obtención de polímeros biodegradables, y hasta donde sabemos no existen precedentes del desarrollo de adhesivos de poliuretano biodegradables. Desde el desarrollo del primer poliuretano hasta nuestros días la mayoría de los polioles y extendedores de cadena utilizados para la obtención de poliuretanos derivan de subproductos del petróleo. Una alternati...

  1. Functional magnetic resonance maps obtained by personal computer; Mapas de resonancia magnetica funcional obtenidos con PC

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, F. j.; Manjon, J. V.; Robles, M. [Universidad Politecnica de Valencia (Spain); Marti-Bonmati, L.; Dosda, R. [Cinica Quiron. Valencia (Spain); Molla, E. [Universidad de Valencia (Spain)

    2001-07-01

    Functional magnetic resonance (fMR) is of special relevance in the analysis of certain types of brain activation. The present report describes the development of a simple software program for use with personal computers (PCs) that analyzes these images and provides functional activation maps. Activation maps are based on the temporal differences in oxyhemoglobin in tomographic images. To detect these differences, intensities registered repeatedly during brain control and activation are compared. The experiments were performed with a 1.5-Tesla MR unit. To verify the reliability of the program fMR studies were carried out in 4 healthy individuals (12 contiguous slices, 80 images per slice every 3.1 seconds for a total of 960 images). All the images were transferred to a PC and were processed pixel by pixel within each sequence to obtain an intensity/time curve. The statistical study of the results (Student's test and cross correlation analysis) made it possible to establish the activation of each pixel. The images were prepared using spatial filtering, temporal filtering, baseline correction, normalization and segmentation of the parenchyma. The postprocessing of the results involved the elimination of single pixels, superposition of an anatomical image of greater spatial resolution and anti-aliasing. The application (Xfun 1.0, Valencia, Spain) was developed in Microsoft Visual C++5.0 Developer Studio for Windows NT Workstation. As a representative example, the program took 8.2 seconds to calculate and present the results of the entire study (12 functional maps). In the motor and visual activation experiments, the activation corresponding to regions proximal to the central sulcus of the hemisphere contralateral to the hand that moved and in the occipital cortex were observed. While programs that calculate activation maps are available, the development of software for PCs running Microsoft Windows ensures several key features for its use on a daily basis: it is easy to employ and has powerful computing capabilities. The program described here is capable of differentiating between the regions of the brain that are activated in response to a stimulus and those that remain unaltered. (Author) 19 refs.

  2. SPATHOGLOTTIS ´SABRINA & ABEL´, HÍBRIDO DE ORQUÍDEA TERRESTRE OBTENIDO EN CUBA

    Directory of Open Access Journals (Sweden)

    Lorenzo Suárez Guerra

    2015-01-01

    Full Text Available Spathoglottis es un género terrestre naturalizado en Cuba, originaria del sureste de Asia y es considerada como una planta de fácil cultivo. En este trabajo se presentan las principales características de un nuevo cultivar de Spathoglottis. ́Sabrina & Abel ́ es el resultado de la polinización manual cruzada realizada en octubre del 2009 entre Spathoglottis unguiculata var. Grapefruit y Spathoglottis kimballiana var Angustifolia.Este híbridoposee un alto potencial ornamental. Se encuentra registrado y publicado en la base de datos de la Sociedad Hortícola Real de Inglaterraen Orchids Review Supplement 121 (1303, Septiembre 2013

  3. Mejora de la calidad del acero obtenido por colada continua mediante influencias electrofísicas

    Directory of Open Access Journals (Sweden)

    Shklyar, V.

    1998-12-01

    Full Text Available Laboratory tests with tin smelted in a crucible and industrial tests with crude steel poured in moulds had been carried out. These metals were subjected to electrophysical influences. As a result of the applied electric field, it is observed in tin that during the solidification, the crystalization temperature and the solidification time are changed. Crystal growth in the electric field direction and an increase of the fracture limit in the steel ingot are observed.

    Se han realizado ensayos de laboratorio con estaño fundido en crisol y a escala industrial con acero líquido vertidos en moldes, sometiendo estos metales a influencias electrofísicas. Como resultado del campo aplicado, en el estaño se observa que durante la solidificación varía la temperatura de cristalización y el tiempo de solidificación. En el lingote de acero se observa un crecimiento de los cristales en dirección del campo eléctrico y un aumento del límite de rotura.

  4. DENDROBIUM «BOHEMIA HABANA». NUEVO CULTIVAR DE ORQUÍDEA EPIFITA OBTENIDO EN CUBA

    Directory of Open Access Journals (Sweden)

    Lorenzo Suárez Guerra

    2013-01-01

    Full Text Available Los Dendrobium, forman parte del género de las orquídeas más cultivadas de todo el mundo. Se le comercializa como flor de corte, material in vitro y planta de pote o maceta. Varios cultivares de Dendrobium son vendidos de este modo y se ubican en el cuarto lugar en ventas entre los productos de floricultura, después de las Palmáceas , Dracaena y Anthurium de corte. En este trabajo se presentan las principales características de un nuevo cultivar de Dendrobium. «Bohemia Habana», es el resultado de la polinización manual cruzada entre Dendrobium aphyllum (Roxb C.E.C. Fisch (syn. Den . pierardii y Dendrobium loddigesii Rolfe . Se encuentra registrado y publicado en la base de datos de la Sociedad Hortícola Real de Inglaterra, en Orchids Review Supplement 118 (1291: 62 Septiembre 2010.

  5. Perfil metabólico obtenido de pool de sueros o de muestras individuales

    OpenAIRE

    Campos Gaona, Rómulo; Díaz González, Félix Hilario; Lacerda, Luciana de Almeida; Coldebella, Arlei

    2005-01-01

    El perfil metabólico se ha usado por debajo de su potencial en la evaluación nutricional y metabólica fundamentalmente por su alto costo que se podría reducir con un pool de muestras de suero de animales bajo las mismas condiciones de manejo. Se trabajó en 210 vacas multíparas durante el periparto sometiendo a las muestras del pool e individuales a iguales condiciones de laboratorio para analizar metabolitos bioquímicos indicadores del metabolismo proteico, energético, mineral y del estatus h...

  6. Comparación de la calidad del coque siderúrgico obtenido a diferentes escalas

    OpenAIRE

    G. Cimadevilla, J. L.; Díaz-Faes, M. E.; Casal, M. D.; Suárez, C.; Barriocanal, C.; Díez, M. A.; Álvarez, R.

    2005-01-01

    Coke cold mechanical strength measured by means of the IRSID test, reactivity towards CO2 (CRI) and post-reaction strength (CSR) are the most important parameters for controlling coke quality in Spain. INCAR was running a semi-industrial coking test plant until July of 1999. Previous to this closure, a comparison of the coke quality was made between the 6 t oven of this test plant and a 250 kg movable wall oven (MWO). It is thus possible to use the coke quality data obt...

  7. "Pinole" de alto valor nutricional obtenido a partir de cereales y leguminosas

    OpenAIRE

    Olaydes Lozano-Aguilar; Esteban Solórzano-Vega; Irma Bernal-Lugo; Hugo Rebolledo-Robles; Carmen Jacinto-Hernández

    2008-01-01

    En nuestro país, gran parte de la población particularmente en las zonas rurales padece desnutrición, una alternativa para disminuir el elevado índice se desnutrición es mejorar el valor nutrimental de los alimentos tradicionales aprovechando los productos vegetales que brindan proteína de bajo costo. El pinole, es un alimento tradicional de México, generalmente elaborado de harina de maíz tostado a veces endulzada y mezclada con cacao, canela o anís. Debido a su ingrediente principal, los pi...

  8. Nuevos genotipos de arroz resistentes a la Piriculariosis obtenidos por cultivo de anteras

    Directory of Open Access Journals (Sweden)

    Rodolfo I Castro

    2012-04-01

    Full Text Available Normal 0 21 false false false ES-CO X-NONE X-NONE MicrosoftInternetExplorer4 Título en inglés: New blast resistant rice genotypes obtained by and anthers culture. Resumen: En la Estación Experimental del Arroz Los Palacios, perteneciente al Instituto Nacional de Ciencias Agrícolas de Cuba (INCA, se efectuaron cruzamientos entre cuatro cultivares resistentes a la Piriculariosis y seis de buen comportamiento agronómico y las anteras de las plantas F2 fueron cultivadas in vitro para evaluar la formación de callos en tres medios líquidos: N6-1, N6-m y NL, así como la regeneración de plantas verdes y albinas, en el medio MS. Las dos primeras generaciones de las nuevas líneas obtenidas fueron evaluadas para caracteres agronómicos y la segunda generación, además, para resistencia frente a la  Piriculariosis. Las líneas que combinaron resistencia a la Piriculariosis y buenos caracteres agronómicos fueron evaluadas en condiciones de infección natural, con alta presión del patógeno. La utilización de la técnica del cultivo de anteras mostró alta dependencia del genotipo y el medio de cultivo. Con el medio NL se lograron los valores más altos para la formación de callos. Se obtuvieron nuevos genotipos resistentes a la Piriculariosis y  de alto rendimiento agrícola. Palabras clave: Arroz; Mejoramiento genético; Cultivo in Vitro de anteras Summary: Crosses were made between four blast resistant and six rice varieties of good agronomic performance, at the Los Palacios Rice Research Station of the National Agricultural Sciences Institute of Cuba (INCA and the anthers from F2 plants were in vitro culture using three liquid media: N6-1, N6m, and NL, for callus formation and after plants regenerations using MS medium. The first two generations of breeding lines were evaluated for agronomic characters and the second generations, also, for Blast resistant. The lines that combined resistance to Blast and good agronomic performance were evaluated under high pressure of natural Blast infection conditions. The success rate of anther culture was highly dependent on the genotype and culture media used. NL medium led to the highest callus formation values. In the process, new blast resistant and high yielding genotypes were obtained. Key words: Rice; Rice Breeding; Anther culture

  9. Materiales nanocompuestos basados en polietileno y filosilicatos laminares obtenidos por mezclado en fundido. Estructura y propiedades

    OpenAIRE

    Villanueva Redón, María del Pilar

    2009-01-01

    El objetivo principal de esta Tesis Doctoral es desarrollar nanocompuestos de LDPE/arcilla mediante mezclado en fundido con mejoras en propiedades mecánicas, térmicas y de barrera a gases o aromas que permitan incrementar las posibilidades de aplicación del polietileno en diversos sectores. Para ello se han empleado filosilicatos laminares (arcillas) de distinta naturaleza: de tipo caolinítico y de tipo montmorillonítico.La investigación llevada a cabo se ha dividido en diferentes fases con e...

  10. Proton and carbon ion therapy

    CERN Document Server

    Lomax, Tony

    2013-01-01

    Proton and Carbon Ion Therapy is an up-to-date guide to using proton and carbon ion therapy in modern cancer treatment. The book covers the physics and radiobiology basics of proton and ion beams, dosimetry methods and radiation measurements, and treatment delivery systems. It gives practical guidance on patient setup, target localization, and treatment planning for clinical proton and carbon ion therapy. The text also offers detailed reports on the treatment of pediatric cancers, lymphomas, and various other cancers. After an overview, the book focuses on the fundamental aspects of proton and carbon ion therapy equipment, including accelerators, gantries, and delivery systems. It then discusses dosimetry, biology, imaging, and treatment planning basics and provides clinical guidelines on the use of proton and carbon ion therapy for the treatment of specific cancers. Suitable for anyone involved with medical physics and radiation therapy, this book offers a balanced and critical assessment of state-of-the-art...

  11. Carbon Nanostructures Containing Polyhedral Oligomeric Silsesquioxanes (POSS)

    NARCIS (Netherlands)

    Potsi, Georgia; Rossos, Andreas; Kouloumpis, Antonios; Antoniou, Myrsini K.; Spyrou, Konstantinos; Karakassides, Michael A.; Gournis, Dimitrios; Rudolf, Petra

    2015-01-01

    This mini review describes the synthesis and properties of carbon nanostructures containing organic-inorganic cage-like polyhedral oligomeric silsesquioxane (POSS). The physical and chemical functionalization of carbon nanomaterials such as graphene, graphene oxide, carbon nanotubes, and fullerenes

  12. Carbon cycle: Global warming then and now

    Science.gov (United States)

    Stassen, Peter

    2016-04-01

    A rapid warming event 55.8 million years ago was caused by extensive carbon emissions. The rate of change of carbon and oxygen isotopes in marine shelf sediments suggests that carbon emission rates were much slower than anthropogenic emissions.

  13. Predators help protect carbon stocks in blue carbon ecosystems

    Science.gov (United States)

    Atwood, Trisha B.; Connolly, Rod M.; Ritchie, Euan G.; Lovelock, Catherine E.; Heithaus, Michael R.; Hays, Graeme C.; Fourqurean, James W.; Macreadie, Peter I.

    2015-12-01

    Predators continue to be harvested unsustainably throughout most of the Earth's ecosystems. Recent research demonstrates that the functional loss of predators could have far-reaching consequences on carbon cycling and, by implication, our ability to ameliorate climate change impacts. Yet the influence of predators on carbon accumulation and preservation in vegetated coastal habitats (that is, salt marshes, seagrass meadows and mangroves) is poorly understood, despite these being some of the Earth's most vulnerable and carbon-rich ecosystems. Here we discuss potential pathways by which trophic downgrading affects carbon capture, accumulation and preservation in vegetated coastal habitats. We identify an urgent need for further research on the influence of predators on carbon cycling in vegetated coastal habitats, and ultimately the role that these systems play in climate change mitigation. There is, however, sufficient evidence to suggest that intact predator populations are critical to maintaining or growing reserves of 'blue carbon' (carbon stored in coastal or marine ecosystems), and policy and management need to be improved to reflect these realities.

  14. Optimal decisions of countries with carbon tax and carbon tariff

    Directory of Open Access Journals (Sweden)

    Yumei Hou

    2015-05-01

    Full Text Available Purpose: Reducing carbon emission has been the core problem of controlling global warming and climate deterioration recently. This paper focuses on the optimal carbon taxation policy levied by countries and the impact on firms’ optimal production decisions. Design/methodology/approach: This paper uses a two-stage game theory model to analyze the impact of carbon tariff and tax. Numerical simulation is used to supplement the theoretical analysis. Findings: Results derived from the paper indicate that the demand in an unstable market is significantly affected by environmental damage level. Carbon tariff is a policy-oriented tax while the carbon tax is a market-oriented one. Comprehensive carbon taxation policy benefit developed countries and basic policy is more suitable for developing countries. Research limitations/implications: In this research, we do not consider random demand and asymmetric information, which may not well suited the reality. Originality/value: This work provides a different perspective in analyzing the impact of carbon tax and tariff. It is the first study to consider two consuming market and the strategic game between two countries. Different international status of countries considered in the paper is also a unique point.

  15. Four advances in carbon-carbon materials technology

    Science.gov (United States)

    Maahs, Howard G.; Vaughn, Wallace L.; Kowbel, Witold

    1994-01-01

    Carbon-carbon composites are a specialty class of materials having many unique properties making these composites attractive for a variety of demanding engineering applications. Chief among these properties are exceptional retention of mechanical properties at temperatures as high as 4000 F, excellent creep resistance, and low density (1.6 to 1.8 g/cu cm). Although carbon-carbon composites are currently in service in a variety of applications, much development work remains to be accomplished before these materials can be considered to be fully mature, realizing their full potential. Four recent technology advances holding particular promise for overcoming current barriers to the wide-spread commercialization of carbon-carbon composites are described. These advances are: markedly improved interlaminar strengths (more than doubled) of two dimensional composites achieved by whiskerization of the fabric reinforcing plies, simultaneously improved oxidation resistance and mechanical properties achieved by the incorporation of matrix-phase oxidation inhibitors based on carborane chemistry, improved oxidation resistance achieved by compositionally graded oxidation protective coatings, and markedly reduced processing times (hours as opposed to weeks or months) accomplished through a novel process of carbon infiltration and coatings deposition based on the use of liquid-phase precursor materials.

  16. Carbon and Carbon Isotope Cycling in the Western Canadian Arctic

    Science.gov (United States)

    Mol, Jacoba; Thomas, Helmuth

    2016-04-01

    Increasing carbon dioxide levels in the atmosphere are having drastic effects on the global oceans. The Arctic Ocean is particularly susceptible to change as warming, sea-ice loss and a weak buffering capacity all influence this complicated semi-enclosed sea. In order to investigate the inorganic carbon system in the Canadian Arctic, water samples were collected in the Beaufort Sea, on the Alaskan shelf, at the Mackenzie river delta, and in Amundsen Gulf during the summer of 2014 and were analyzed for dissolved inorganic carbon (DIC), total alkalinity (TA), DI13C and 18O isotopes. Carbon isotopes are used to investigate the role of biological production on the uptake and transfer of inorganic carbon to depth. A preferential uptake of the lighter 12C relative to the heavier 13C isotope during biological production leads to a fractionation of the 13C/12C isotopes in both the organic matter and the water column. This results in an enrichment of DI13C in the high productivity surface waters and a depletion of DI13C at depth. Physical processes including freshwater input, brine rejection, and water mass mixing are investigated through the measurement of oxygen isotopes. Differences in the carbon system across the study area due to both biological and physical processes are assessed using depth profiles of DI13C and related carbon system parameters.

  17. Microstructure of carbon fiber preform and distribution of pyrolytic carbon by chemical vapor infiltration

    Institute of Scientific and Technical Information of China (English)

    陈建勋; 黄伯云

    2004-01-01

    The carbon/carbon composites were made by chemical vapor infiltration(CVI) with needled felt preform. The distribution of the pyrolytic carbon in the carbon fiber preform was studied by polarized light microscope(PLM) and scanning electronic microscope(SEM). The experimental results indicate that the amount of pyrolytic carbon deposited on the surface of chopped carbon fiber is more than that on the surface of long carbon fiber. The reason is the different porosity between the layer of chopped carbon fiber and long carbon fiber. The carbon precursor gas which passes through the part of chopped carbon fibers decomposes and deposits on the surface of chopped carbon fiber. The pyrolytic carbon on the surface of long carbon fibers is produced by the carbon precursor gas diffusing from the chopped fiber and the Z-d fiber. Uniform pore distribution and porosity in preform are necessary for producing C/C composites with high properties.

  18. Counting the cost of carbon. Low carbon economy index 2011

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-11-15

    Achieving the rates of decarbonisation needed to stay within the 2 degrees target agreed by governments in Cancun in 20101 requires a revolution in the way the world produces and uses energy. A transformation in financing will also be necessary to achieve the transition at the scale and speed needed. PwC published the first Low Carbon Economy Index ahead of the COP15 in Copenhagen, 2009. This looked at the progress of the G20 economies against a 2000-based carbon budget estimated by PwC. Carbon intensity is our preferred metric for analysing countries' movements towards a low carbon economy, as it accounts for expected economic growth, and can generate comparable targets. The carbon intensity of an economy is the emissions per unit of GDP and is affected by a country's fuel mix, energy efficiency and the proportion of industrial versus service sectors. Since COP 16 in Cancun, there has been an increasing focus on the cost of meeting the low carbon challenge and raising the capital required to finance it. This year's Low Carbon Economy Index focuses on this global financing gap and the reforms that might help to fill it. In section one we present our analysis of economic and emissions growth and ask whether we are decarbonising fast enough. The second section asks how much it will cost and can we afford it. We highlight the global financing gap, and focus on efforts to increase low carbon generation in the UK and South Africa. The report concludes by outlining some steps that could be taken to help meet the low carbon challenge.

  19. The carbon footprint of reinforced concrete

    OpenAIRE

    Purnell, P

    2013-01-01

    As legislation forces significant reductions in the operational carbon dioxide emissions of the built environment, increasing attention is focused on the embodied carbon of structural materials. As the most prevalent structural material, the embodied carbon of concrete is of paramount interest. Previous direct or indirect analyses of embodied carbon in concrete have treated it either as an elemental material with a value of single embodied carbon, or calculated embodied carbon for a limited r...

  20. Carbon dioxide gasification of carbon black: isotope study of carbonate catalysis

    International Nuclear Information System (INIS)

    Temperature-programmed reaction was used with labeled isotopes (13C and 18O) to study interactions between carbon black and potassium carbonate in pure He and 10% CO2/90% He atmospheres. Catalytic gasification precursor complexes were observed. Carbon and oxygen-bearing carbon surface groups interacted with the carbonate above 500 K to form surface complexes. Between 500 and 950 K, and in the presence of gaseous CO2, the complexes participated in C and O exchange with the gas phase while oxygen atoms within the complexes also exchanged with those on the carbon surface. As the temperature rose, the complexes decomposed, with CO2 the initial product. Decomposition started around 500 K in pure He, and around 950 K in CO2/He. Catalytic gasification began only after decomposition of significant portions of the complexes. Elemental potassium formed, and the active catalyst appears to alternate between being potassium metal and a potassium-oxygen-carbon complex. Potassium carbonate is not part of the catalytic cycle. 20 references, 10 figures

  1. Lignin-Derived Advanced Carbon Materials.

    Science.gov (United States)

    Chatterjee, Sabornie; Saito, Tomonori

    2015-12-01

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure-property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templated carbon, are discussed. PMID:26568373

  2. Lignin-Derived Advanced Carbon Materials.

    Science.gov (United States)

    Chatterjee, Sabornie; Saito, Tomonori

    2015-12-01

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. By applying specific pretreatments and manufacturing methods, lignin can be converted into a variety of value-added carbon materials. However, the physical and chemical heterogeneities of lignin complicate its use as a feedstock. Herein lignin manufacturing process, the effects of pretreatments and manufacturing methods on the properties of product lignin, and structure-property relationships in various applications of lignin-derived carbon materials, such as carbon fibers, carbon mats, activated carbons, carbon films, and templated carbon, are discussed.

  3. Switching to carbon-free production processes: Implications for carbon leakage and border carbon adjustment

    International Nuclear Information System (INIS)

    Climate policy under partial global compliance raises concerns regarding carbon leakage. While border carbon adjustment (BCA) measures are a potential remedy, they have also been criticised on various grounds. This paper therefore investigates whether a policy fostering the switch to carbon-free technologies can substitute for BCAs. A reason for the effectiveness of a targeted technology policy is that major leakage prone sectors (such as iron and steel), have two main sources of carbon emissions, combustion of fossil fuels and industrial processes. While combustion emissions can be reduced relatively easy by increasing energy efficiency, reducing process emissions requires a switch to low-carbon production processes, e.g. in steel production by deploying electrolysis based on large-scale solar electricity. We show by means of a multi-regional computable general equilibrium analysis that such a switch in steel production technology can eliminate a significant fraction of carbon leakage and also increase sectoral output and welfare. Since the necessary technologies are not available at large scale yet (however, are likely to be by 2020), a transitional BCA scheme may be a crucial supportive instrument to foster such technology switches. Yet, in the long run BCA should be phased out to preserve the incentive for carbon-free innovation. - Highlights: • A carbon-free technology switch in iron production considerably reduces total leakage. • Border carbon adjustment (BCA) may impede domestic industrial decarbonisation. • A targeted technology policy is superior to BCA in fostering low-carbon investments. • But implemented as a transitory instrument, BCA reinforces technology policy

  4. Separating proteins with activated carbon.

    Science.gov (United States)

    Stone, Matthew T; Kozlov, Mikhail

    2014-07-15

    Activated carbon is applied to separate proteins based on differences in their size and effective charge. Three guidelines are suggested for the efficient separation of proteins with activated carbon. (1) Activated carbon can be used to efficiently remove smaller proteinaceous impurities from larger proteins. (2) Smaller proteinaceous impurities are most efficiently removed at a solution pH close to the impurity's isoelectric point, where they have a minimal effective charge. (3) The most efficient recovery of a small protein from activated carbon occurs at a solution pH further away from the protein's isoelectric point, where it is strongly charged. Studies measuring the binding capacities of individual polymers and proteins were used to develop these three guidelines, and they were then applied to the separation of several different protein mixtures. The ability of activated carbon to separate proteins was demonstrated to be broadly applicable with three different types of activated carbon by both static treatment and by flowing through a packed column of activated carbon. PMID:24898563

  5. Separating proteins with activated carbon.

    Science.gov (United States)

    Stone, Matthew T; Kozlov, Mikhail

    2014-07-15

    Activated carbon is applied to separate proteins based on differences in their size and effective charge. Three guidelines are suggested for the efficient separation of proteins with activated carbon. (1) Activated carbon can be used to efficiently remove smaller proteinaceous impurities from larger proteins. (2) Smaller proteinaceous impurities are most efficiently removed at a solution pH close to the impurity's isoelectric point, where they have a minimal effective charge. (3) The most efficient recovery of a small protein from activated carbon occurs at a solution pH further away from the protein's isoelectric point, where it is strongly charged. Studies measuring the binding capacities of individual polymers and proteins were used to develop these three guidelines, and they were then applied to the separation of several different protein mixtures. The ability of activated carbon to separate proteins was demonstrated to be broadly applicable with three different types of activated carbon by both static treatment and by flowing through a packed column of activated carbon.

  6. Ocean uptake of carbon dioxide

    International Nuclear Information System (INIS)

    Factors controlling the capacity of the ocean for taking up anthropogenic C02 include carbon chemistry, distribution of alkalinity, pCO2 and total concentration of dissolved C02, sea-air pCO2 difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C02 uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C02 from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C02 fertilization is a potential candidate for such missing carbon sinks

  7. The NASA Carbon Monitoring System

    Science.gov (United States)

    Hurtt, G. C.

    2015-12-01

    Greenhouse gas emission inventories, forest carbon sequestration programs (e.g., Reducing Emissions from Deforestation and Forest Degradation (REDD and REDD+), cap-and-trade systems, self-reporting programs, and their associated monitoring, reporting and verification (MRV) frameworks depend upon data that are accurate, systematic, practical, and transparent. A sustained, observationally-driven carbon monitoring system using remote sensing data has the potential to significantly improve the relevant carbon cycle information base for the U.S. and world. Initiated in 2010, NASA's Carbon Monitoring System (CMS) project is prototyping and conducting pilot studies to evaluate technological approaches and methodologies to meet carbon monitoring and reporting requirements for multiple users and over multiple scales of interest. NASA's approach emphasizes exploitation of the satellite remote sensing resources, computational capabilities, scientific knowledge, airborne science capabilities, and end-to-end system expertise that are major strengths of the NASA Earth Science program. Through user engagement activities, the NASA CMS project is taking specific actions to be responsive to the needs of stakeholders working to improve carbon MRV frameworks. The first phase of NASA CMS projects focused on developing products for U.S. biomass/carbon stocks and global carbon fluxes, and on scoping studies to identify stakeholders and explore other potential carbon products. The second phase built upon these initial efforts, with a large expansion in prototyping activities across a diversity of systems, scales, and regions, including research focused on prototype MRV systems and utilization of COTS technologies. Priorities for the future include: 1) utilizing future satellite sensors, 2) prototyping with commercial off-the-shelf technology, 3) expanding the range of prototyping activities, 4) rigorous evaluation, uncertainty quantification, and error characterization, 5) stakeholder

  8. Atmospheric carbon dioxide and the global carbon cycle

    Energy Technology Data Exchange (ETDEWEB)

    Trabalka, J R [ed.

    1985-12-01

    This state-of-the-art volume presents discussions on the global cycle of carbon, the dynamic balance among global atmospheric CO2 sources and sinks. Separate abstracts have been prepared for the individual papers. (ACR)

  9. From Carbon Nanotube Crystals to Carbon Nanotube Flowers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhengjun; ZHAO Ye; ZHOU Ya

    2005-01-01

    We have investigated the very initial deposition stages of chemical vapor deposition (CVD) with ferrocene (Fe(C5H5)2) and xylene (C8H10) for growing carbon nanotubes, and made clear that the mechanism for the self-organization behaviors of nanotubes at different growth stages by this approach. For instance, the organization of nanotubes into flower-like structures at prolonged deposition is developed from the crystal-like structures formed at early growth stages, both of which are closely related to and determined by the very initial deposition stages of this CVD approach. Based on this approach, ways have been established to build up different architectures of carbon nanotubes, by controlling the initial deposition stages of the CVD process, with which we have realized the selective growth of self-organized carbon nanotube structures. This study provides a new idea for growing carbon nanotube architectures by CVD.

  10. Carbon films produced from ionic liquid carbon precursors

    Science.gov (United States)

    Dai, Sheng; Luo, Huimin; Lee, Je Seung

    2013-11-05

    The invention is directed to a method for producing a film of porous carbon, the method comprising carbonizing a film of an ionic liquid, wherein the ionic liquid has the general formula (X.sup.+a).sub.x(Y.sup.-b).sub.y, wherein the variables a and b are, independently, non-zero integers, and the subscript variables x and y are, independently, non-zero integers, such that ax=by, and at least one of X.sup.+ and Y.sup.- possesses at least one carbon-nitrogen unsaturated bond. The invention is also directed to a composition comprising a porous carbon film possessing a nitrogen content of at least 10 atom %.

  11. Carbon budgets and carbon sequestration potential of Indian forests

    NARCIS (Netherlands)

    Kaul, M.

    2010-01-01

    Keywords: Carbon uptake, Forest biomass, Bioenergy, Land use change, Indian forests, Deforestation, Afforestation, Rotation length, Trees outside forests. Global climate change is a widespread and growing concern that has led to extensive international discussions and negotiations. Responses to thi

  12. Carbonate Ion Effects on Coccolith Carbon and Oxygen Isotopes

    Science.gov (United States)

    Ziveri, P.; Probert, I.; Stoll, H. M.

    2006-12-01

    The stable oxygen and carbon isotopic composition of biogenic calcite constitutes one of the primary tools used in paleoceanographic reconstructions. The δ18O of shells of ocean floor microfossils and corals reflects the composition of the paleo-seawater as they use the oxygen to build up their calcite and aragonite shells. The δ13C is used to reconstruct variations in the carbon isotopic composition of dissolved inorganic carbon in the ocean, which is controlled by biological productivity through the removal of isotopically light carbon in organic matter. To be effective and sensitive tools for understanding photic zone processes it is first necessary to understand the various biological fractionations associated with carbonate precipitation. To date, isotopic fractionation models are mainly based on foraminifera and corals but not on coccoliths, tiny plates produced by coccolithophore algae, which are often the most dominant carbonate contributors to pelagic sediments. As photosynthetic organisms, their chemistry can provide a sensitive tool for understanding photic zone processes. Coccoliths may be the most important carbonate phase for geochemical analysis in sediments where foraminifera are less common and/or core material is limited, such as in subpolar regions and for Early Cenozoic and Mesozoic sediments. Here we report experimental results on a common living coccolithophore species showing that the 13C/12C and 18O/16O ratios decrease with the increase of HCO^{3-} (CO32-). The selected species are among the heaviest calcifying extant coccolithophores and are major contributors to present coccolith carbonate export production. Because coccolithophores are photosynthetic organisms that calcify intracellularly in specialized vesicles, the challenge lies in ascertaining how kinetic and thermodynamic processes of isotopic fractionation are linked to cellular carbon "transport" and carbonate precipitation. This is a daunting challenge since studies have not

  13. Carbon isotope geochemistry and geobiology

    Science.gov (United States)

    Desmarais, D.

    1985-01-01

    Carbon isotope fractionation values were used to understand the history of the biosphere. For example, plankton analyses confirmed that marine extinctions at the end of the Cretaceous period were indeed severe (see Hsu's article in Sundquist and Broeker, 1984). Variations in the isotopic compositions of carbonates and evaporitic sulfates during the Paleozoic reflect the relative abundances of euxinic (anoxic) marine environments and organic deposits from terrestrial flora. The carbon isotopic composition of Precambrian sediments suggest that the enzyme ribulose bisphosphate carboxylase has existed for perhaps 3.5 billion years.

  14. Developing a Carbon Observing System

    Science.gov (United States)

    Moore, B., III

    2015-12-01

    There is a clear need to better understand and predict future climate change, so that science can more confidently inform climate policy, including adaptation planning and future mitigation strategies. Understanding carbon cycle feedbacks, and the relationship between emissions (fossil and land use) and the resulting atmospheric carbon dioxide (CO2) and methane (CH4) concentrations in a changing climate has been recognized as an important goal by the IPCC. The existing surface greenhouse gas observing networks provide accurate and precise measurements of background values, but they are not configured to target the extended, complex and dynamic regions of the carbon budget. Space Agencies around the globe are committed to CO2 and CH4 observations: GOSAT-1/2, OCO-2/3, MERLin, TanSat, and CarbonSat. In addition to these Low Earth Orbit (LEO) missions, a new mission in Geostationary Orbit (GEO), geoCARB, which would provide mapping-like measurements of carbon dioxide, methane, and carbon monoxide concentrations over major land areas, has been recently proposed to the NASA Venture Program. These pioneering missions do not provide the spatial/temporal coverage to answer the key carbon-climate questions at process relevant scales nor do they address the distribution and quantification of anthropogenic sources at urban scales. They do demonstrate, however, that a well-planned future system of system integrating space-based LEO and GEO missions with extensive in situ observations could provide the accuracy, spatial resolution, and coverage needed to address critical open issues in the carbon-climate system. Dr. Diana Wickland devoted enormous energy in developing a comprehensive apprioach to understand the global carbon cycle; she understood well that an integrated, coordinated, international approach is needed. This shines through in her recent contribution in co-chairing the team that produced the "CEOS Strategy for Carbon Observations from Space." A NASA-funded community

  15. Carbon storage in forest soil

    International Nuclear Information System (INIS)

    The article reviews research on short and long term carbon storage. A Norwegian programme with the objective of increasing knowledge of key processes which govern the carbon storage and loss of CO2 from forest soil in Norway is mentioned. Topics that will be studied are: The production and loss of CO2 from the soil, root ecology, the microorganism ability of degrading organic compounds, transport and loss of organic compounds through the soil to creeks and lakes and the modelling of carbon currents and storage in various forest ecosystems both in the soil and above

  16. Carbon Nanotube Purification and Functionalization

    Science.gov (United States)

    Lebron, Marisabel; Mintz, Eric; Smalley, Richard E.; Meador, Michael A.

    2003-01-01

    Carbon nanotubes have the potential to significantly enhance the mechanical, thermal, and electrical properties of polymers. However, dispersion of carbon nanotubes in a polymer matrix is hindered by the electrostatic forces that cause them to agglomerate. Chemical modification of the nanotubes is necessary to minimize these electrostatic forces and promote adhesion between the nanotubes and the polymer matrix. In a collaborative research program between Clark Atlanta University, Rice University, and NASA Glenn Research Center several approaches are being explored to chemically modify carbon nanotubes. The results of this research will be presented.

  17. Model protocells photochemically reduce carbonate to organic carbon

    Energy Technology Data Exchange (ETDEWEB)

    Folsome, C.; Brittain, A.

    1981-06-11

    Synthetic cell-sized organic microstructures effect the long-wavelength uv photosynthesis of organic products from carbonate. Formaldehyde is the most abundant photoproduct and water is the major proton donor for this reduced form of carbon. We show here that these results for model phase-bounded systems are consistent with the postulate that metabolism of progenitors to the earliest living cells could have been, at least in part, photosynthetic.

  18. AASPT Carbon/Carbon Aircraft Brake Disk Granted MPA

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Xi'an Chaoma Technology Co. Ltd. was issued Parts Manufacturer Approval (PMA) for Carbon/Carbon aircraft brake disk for Airbus 320 series by Civil Aviation Administration of China (CAAC). The company is held by Academy of Aerospace Solid Propulsion Technology (AASPT), a subsidiary of China Aerospace Science and Technology Corporation (CASC). It is the first approval given to a Chinese company to design and produce brakes for main civilian aircraft.

  19. Carbon-optimal and carbon-neutral supply chains

    OpenAIRE

    Caro, F; Corbett, CJ; Tan, T Tarkan; Zuidwijk, RA

    2011-01-01

    Carbon footprinting is a tool for firms to determine the total greenhouse gas (GHG) emissions associated with their supply chain or with a unit of final product or service. Carbon footprinting efforts typically aim to identify where best to invest in emission reduction efforts, and/or to determine the proportion of total emissions that an individual firm is accountable for, whether financially and/or operationally. A major and under-recognized challenge in determining the appropriate allocati...

  20. Method for fabricating composite carbon foam

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    2001-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

  1. Capacitor with a composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1999-04-27

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy. 1 fig.

  2. Capacitor with a composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    1999-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid partides being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

  3. Cytotoxicity of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    With large-scale production and application at large scale, carbon nanotubes (CNTs) may cause ad-verse response to the environment and human health. Thus, study on bio-effects and safety of CNTs has attracted great attention from scientists and governments worldwide. This report briefly summa-rizes the main results from the in vitro toxicity study of CNTs. The emphasis is placed on the descrip-tion of a variety of factors affecting CNTs cytotoxicity, including species of CNTs, impurities contained, lengths of CNTs, aspect ratios, chemical modification, and assaying methods of cytotoxicity. However, experimental information obtained thus far on CNTs’ cytotoxicity is lacking in comparability, and some-times there is controversy about it. In order to assess more accurately the potential risks of CNTs to human health, we suggest that care should be taken for issues such as chemical modification and quantitative characterization of CNTs in cytotoxicity assessment. More importantly, studies on physical and chemical mechanisms of CNTs’ cytotoxicity should be strengthened; assaying methods and evaluating criteria characterized by nanotoxicology should be gradually established.

  4. Cytotoxicity of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying; LI WenXin

    2008-01-01

    With large-scale production and application at large scale, carbon nanotubes (CNTs) may cause ad-verse response to the environment and human health. Thus, study on bio-effects and safety of CNTs has attracted great attention from scientists and governments worldwide. This report briefly summa-rizes the main results from the in vitro toxicity study of CNTs. The emphasis is placed on the descrip-tion of a variety of factors affecting CNTs cytotoxicity, including species of CNTs, impurities contained,lengths of CNTs, aspect ratios, chemical modification, and assaying methods of cytotoxicity. However,experimental information obtained thus far on CNTs' cytotoxicity is lacking in comparability, and some-times there is controversy about it. In order to assess more accurately the potential risks of CNTs to human health, we suggest that care should be taken for issues such as chemical modification and quantitative characterization of CNTa in cytotoxicity assessment. More importantly, studies on physical and chemical mechanisms of CNTs' cytotoxicity should be strengthened; assaying methods and evaluating criteria characterized by nanotoxicology should be gradually established.

  5. Teslaphoresis of Carbon Nanotubes.

    Science.gov (United States)

    Bornhoeft, Lindsey R; Castillo, Aida C; Smalley, Preston R; Kittrell, Carter; James, Dustin K; Brinson, Bruce E; Rybolt, Thomas R; Johnson, Bruce R; Cherukuri, Tonya K; Cherukuri, Paul

    2016-04-26

    This paper introduces Teslaphoresis, the directed motion and self-assembly of matter by a Tesla coil, and studies this electrokinetic phenomenon using single-walled carbon nanotubes (CNTs). Conventional directed self-assembly of matter using electric fields has been restricted to small scale structures, but with Teslaphoresis, we exceed this limitation by using the Tesla coil's antenna to create a gradient high-voltage force field that projects into free space. CNTs placed within the Teslaphoretic (TEP) field polarize and self-assemble into wires that span from the nanoscale to the macroscale, the longest thus far being 15 cm. We show that the TEP field not only directs the self-assembly of long nanotube wires at remote distances (>30 cm) but can also wirelessly power nanotube-based LED circuits. Furthermore, individualized CNTs self-organize to form long parallel arrays with high fidelity alignment to the TEP field. Thus, Teslaphoresis is effective for directed self-assembly from the bottom-up to the macroscale. PMID:27074626

  6. The Reionisation of Carbon

    CERN Document Server

    Finlator, K; Huang, S; Davé, R; Zackrisson, E; Oppenheimer, B D

    2014-01-01

    Observations suggest that CII was more abundant than CIV in the intergalactic medium towards the end of the hydrogen reionisation epoch. This transition provides a unique opportunity to study the enrichment history of intergalactic gas and the growth of the ionising background (UVB) at early times. We study how carbon absorption evolves from z=10-5 using a cosmological hydrodynamic simulation that includes a self-consistent multifrequency UVB as well as a well-constrained model for galactic outflows to disperse metals. Our predicted UVB is within 2-4 times that of Haardt & Madau (2012), which is fair agreement given the uncertainties. Nonetheless, we use a calibration in post-processing to account for Lyman-alpha forest measurements while preserving the predicted spectral slope and inhomogeneity. The UVB fluctuates spatially in such a way that it always exceeds the volume average in regions where metals are found. This implies both that a spatially-uniform UVB is a poor approximation and that metal absorp...

  7. NDE for Characterizing Oxidation Damage in Reinforced Carbon-Carbon

    Science.gov (United States)

    Roth, Don J.; Rauser, Richard W.; Jacobson, nathan S.; Wincheski, Russell A.; Walker, James L.; Cosgriff, Laura A.

    2009-01-01

    In this study, coated reinforced carbon-carbon (RCC) samples of similar structure and composition as that from the NASA space shuttle orbiter s thermal protection system were fabricated with slots in their coating simulating craze cracks. These specimens were used to study oxidation damage detection and characterization using NDE methods. These specimens were heat treated in air at 1143 and 1200 C to create cavities in the carbon substrate underneath the coating as oxygen reacted with the carbon and resulted in its consumption. The cavities varied in diameter from approximately 1 to 3 mm. Single-sided NDE methods were used since they might be practical for on-wing inspection, while x-ray micro-computed tomography (CT) was used to measure cavity sizes in order to validate oxidation models under development for carbon-carbon materials. An RCC sample having a naturally-cracked coating and subsequent oxidation damage was also studied with x-ray micro-CT. This effort is a follow-on study to one that characterized NDE methods for assessing oxidation damage in an RCC sample with drilled holes in the coating. The results of that study are briefly reviewed in this article as well. Additionally, a short discussion on the future role of simulation to aid in these studies is provided.

  8. Carbon isotopes in biological carbonates: Respiration and photosynthesis

    Science.gov (United States)

    McConnaughey, T.A.; Burdett, J.; Whelan, J.F.; Paull, C.K.

    1997-01-01

    Respired carbon dioxide is an important constituent in the carbonates of most air breathing animals but is much less important in the carbonates of most aquatic animals. This difference is illustrated using carbon isotope data from freshwater and terrestrial snails, ahermatypic corals, and chemoautotrophic and methanotrophic pelecypods. Literature data from fish otoliths and bird and mammal shell and bone carbonates are also considered. Environmental CO2/O2 ratios appear to be the major controlling variable. Atmospheric CO2/O2 ratios are about thirty times lower than in most natural waters, hence air breathing animals absorb less environmental CO2 in the course of obtaining O2. Tissue CO2 therefore, does not isotopically equilibrate with environmental CO2 as thoroughly in air breathers as in aquatic animals, and this is reflected in skeletal carbonates. Animals having efficient oxygen transport systems, such as vertebrates, also accumulate more respired CO2 in their tissues. Photosynthetic corals calcify mainly during the daytime when photosynthetic CO2 uptake is several times faster than respiratory CO2 release. Photosynthesis, therefore, affects skeletal ??13C more strongly than does respiration. Corals also illustrate how "metabolic" effects on skeletal isotopic composition can be estimated, despite the presence of much larger "kinetic" isotope effects. Copyright ?? 1997 Elsevier Science Ltd.

  9. Carbon 14 dating; La datation par le carbone 14

    Energy Technology Data Exchange (ETDEWEB)

    Laj, C.; Mazaud, A.; Duplessy, J.C. [CEA Saclay, Lab. des Sciences du Climat et de l' Environnement, 91 - Gif-sur-Yvette (France)

    2004-03-01

    In this article time dating based on carbon 14 method is reviewed, its limits are explained and recent improvements are presented. Carbon 14 is a by-product of the interactions of cosmic protons with air molecules. The fluctuations of the quantity of carbon 14 present in the atmosphere are responsible for the shift observed between the result given by the method and the real age. This shift appears for ages greater than 2000 years and is estimated to 1000 years for an age of 10.000 years. As a consequence carbon 14 dating method requires calibration by comparing with other methods like dendrochronology (till 11.000 years) and time dating of fossil corals (till 26.000 years and soon till 50.000 years). It is assumed that the fluctuations of carbon 14 in the atmosphere are due to: - the changes in the intensity and composition of cosmic radiations itself (due to the motion of the sun system through the galaxy or due to the explosion of a super-novae in the surroundings of the sun system); - the changes of the earth magnetic field that diverts cosmic rays; and - the changes in the interactions between the atmosphere and the oceans knowing that 40 tons of carbon 14 are dissolved in seas while only 1 ton belongs to the atmosphere. (A.C.)

  10. Voltammetric Response of Epinephrine at Carbon Nanotube Modified Glassy Carbon Electrode and Activated Glassy Carbon Electrode

    Institute of Scientific and Technical Information of China (English)

    WANG Juan; TANG Ping; ZHAO Fa-qiong; ZENG Bai-zhao

    2005-01-01

    The electrochemical behavior of epinephrine at activated glassy carbon electrode and carbon nanotube-coated glassy carbon electrode was studied. Epinephrine could exhibit an anodic peak at about 0.2 V (vs. SCE) at bare glassy carbon electrode, but it was very small.However, when the electrode was activated at certain potential (i. e. 1.9V) or modified with carbon nanotube, the peak became more sensitive,resulting from the increase in electrode area in addition to the electrostatic attraction. Under the selected conditions, the anodic peak current was linear to epinephrine concentration in the range of 3.3 × 10-7-1.1 × 10-5mol/L at activated glassy carbon electrode and in the range of 1.0 × 10-6-5.0 × 10-5 mol/L at carbon nanotube-coated electrode. The correlation coefficients were 0. 998 and 0. 997, respectively. The determination limit was 1.0 × 10-7 mol/L. The two electrodes have been successfully applied for the determination of epinephrine in adrenaline hydrochloride injection with recovery of 95%-104%.

  11. Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Loring, John S.; Chen, Jeffrey; Benezeth Ep Gisquet, Pascale; Qafoku, Odeta; Ilton, Eugene S.; Washton, Nancy M.; Thompson, Christopher J.; Martin, Paul F.; McGrail, B. Peter; Rosso, Kevin M.; Felmy, Andrew R.; Schaef, Herbert T.

    2015-07-14

    Continental flood basalts are attractive formations for geologic sequestration of carbon dioxide because of their reactive divalent-cation containing silicates, such as forsterite (Mg2SiO4), suitable for long-term trapping of CO2 mineralized as metal carbonates. The goal of this study was to investigate at a molecular level the carbonation products formed during the reaction of forsterite with supercritical CO2 (scCO2) as a function of the concentration of H2O adsorbed to the forsterite surface. Experiments were performed at 50 °C and 90 bar using an in situ IR titration capability, and post-reaction samples were examined by ex situ techniques, including SEM, XPS, FIB-TEM, TGA-MS, and MAS-NMR. Carbonation products and reaction extents varied greatly with adsorbed H2O. We show for the first time evidence of Mg-carbonate surface complexation under wet scCO2 conditions. Carbonate is found to be coordinated to Mg at the forsterite surface in a predominately bidentate fashion at adsorbed H2O concentrations below 27 µmol/m2. Above this concentration and up to 76 µmol/m2, monodentate coordinated complexes become dominant. Beyond a threshold adsorbed H2O concentration of 76 µmol/m2, crystalline carbonates continuously precipitate as magnesite, and the particles that form are hundreds of times larger than the estimated thicknesses of the adsorbed water films of about 7 to 15 Å. At an applied level, these results suggest that mineral carbonation in scCO2 dominated fluids near the wellbore and adjacent to caprocks will be insignificant and limited to surface complexation, unless adsorbed H2O concentrations are high enough to promote crystalline carbonate formation. At a fundamental level, the surface complexes and their dependence on adsorbed H2O concentration give insights regarding forsterite dissolution processes and magnesite nucleation and growth.

  12. Carbon beams, production and acceleration

    International Nuclear Information System (INIS)

    Installation, test and working conditions of a new negative-ion facility of the Salazar EN tandem are briefly described. Carbon is the material used for the test and the heavy ion stripping phenomenon is reviewed. (author)

  13. High capacity carbon dioxide sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Steven Dean; Alptekin, Gokhan; Jayaraman, Ambalavanan

    2015-09-01

    The present invention provides a sorbent for the removal of carbon dioxide from gas streams, comprising: a CO.sub.2 capacity of at least 9 weight percent when measured at 22.degree. C. and 1 atmosphere; an H.sub.2O capacity of at most 15 weight percent when measured at 25.degree. C. and 1 atmosphere; and an isosteric heat of adsorption of from 5 to 8.5 kilocalories per mole of CO.sub.2. The invention also provides a carbon sorbent in a powder, a granular or a pellet form for the removal of carbon dioxide from gas streams, comprising: a carbon content of at least 90 weight percent; a nitrogen content of at least 1 weight percent; an oxygen content of at most 3 weight percent; a BET surface area from 50 to 2600 m.sup.2/g; and a DFT micropore volume from 0.04 to 0.8 cc/g.

  14. Nitrogen-doped hydrothermal carbons

    Energy Technology Data Exchange (ETDEWEB)

    Titirici, Maria-Magdalena; White, Robin J. [Max-Planck-Institute of Colloids and Interfaces, Potsdam (Germany). Dept. of Colloid Chemistry; Zhao, Li [Max-Planck-Institute of Colloids and Interfaces, Potsdam (Germany). Dept. of Colloid Chemistry; National Center for Nanoscience and Technology, Beijing (China)

    2012-07-01

    Nitrogen doped carbon materials are now playing an important role in cutting edge innovations for energy conversion and storage technologies such as supercapacitors and proton exchange membrane fuel cells as well as in catalytic applications, adsorption and CO{sub 2} capture. The production of such materials using benign aqueous based processes, mild temperatures and renewable precursors is of great promise in addressing growing environmental concerns for cleaner power sources at a time of increasing global demand for energy. In this perspective, we show that nitrogen doped carbons prepared using sustainable processes such as ''Hydrothermal Carbonisation'' has advantages in many applications over the conventional carbons. We also summarize an array of synthetic strategies used to create such nitrogen doped carbons, and discuss the application of these novel materials. (orig.)

  15. Mirador - Carbon Cycle and Ecosystems

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. This Focus Area deals with the cycling of carbon in reservoirs and ecosystems as it changes naturally, is changed by humans,...

  16. Carbon Fiber Technology Facility (CFTF)

    Data.gov (United States)

    Federal Laboratory Consortium — Functionally within the MDF, ORNL operates DOE’s unique Carbon Fiber Technology Facility (CFTF)—a 42,000 ft2 innovative technology facility and works with leading...

  17. A comparison of carbon calculators

    International Nuclear Information System (INIS)

    International attention to carbon dioxide emissions is turning to an individual's contribution, or 'carbon footprint.' Calculators that estimate an individual's CO2 emissions have become more prevalent on the internet. Even with similar inputs, however, these calculators can generate varying results, often by as much as several metric tons per annum per individual activity. This paper examines the similarities and differences among ten US-based calculators. Overall, the calculators lack consistency, especially for estimates of CO2 emissions from household electricity consumption. In addition, most calculators lack information about their methods and estimates, which impedes comparison and validation. Although carbon calculators can promote public awareness of carbon emissions from individual behavior, this paper reveals the need for improved consistency and transparency in the calculators

  18. Carbon-free induction furnace

    Science.gov (United States)

    Holcombe, Cressie E.; Masters, David R.; Pfeiler, William A.

    1985-01-01

    An induction furnace for melting and casting highly pure metals and alloys such as uranium and uranium alloys in such a manner as to minimize contamination of the melt by carbon derived from the materials and the environment within the furnace. The subject furnace is constructed of carbon free materials and is housed within a conventional vacuum chamber. The furnace comprises a ceramic oxide crucible for holding the charge of metal or alloy. The heating of the crucible is achieved by a plasma-sprayed tungsten susceptor surrounding the crucible which, in turn, is heated by an RF induction coil separated from the susceptor by a cylinder of inorganic insulation. The furnace of the present invention is capable of being rapidly cycled from ambient temperatures to about 1650.degree. C. for effectively melting uranium and uranium alloys without the attendant carbon contamination problems previously encountered when using carbon-bearing furnace materials.

  19. Non-carbon induction furnace

    Science.gov (United States)

    Holcombe, C.E.; Masters, D.R.; Pfeiler, W.A.

    1984-01-06

    The present invention is directed to an induction furnace for melting and casting highly pure metals and alloys such as uranium and uranium alloys in such a manner as to minimize contamination of the melt by carbon derived from the materials and the environment within the furnace. The subject furnace is constructed of non-carbon materials and is housed within a conventional vacuum chamber. The furnace comprises a ceramic oxide crucible for holding the charge of metal or alloys. The heating of the crucible is achieved by a plasma-sprayed tungsten susceptor surrounding the crucible which, in turn, is heated by an rf induction coil separated from the susceptor by a cylinder of inorganic insulation. The furnace of the present invention is capable of being rapidly cycled from ambient temperatures to about 1650/sup 0/C for effectively melting uranium and uranium alloys without the attendant carbon contamination problems previously encountered when using carbon-bearing furnace materials.

  20. The process of carbon creation

    CERN Multimedia

    El-Eid, M F

    2005-01-01

    In the Universe, the element carbon is created only in stars, in a remarkable reaction called the triple-α process. Fresh insights into the reaction now come from the latest experiments carried out on Earth

  1. Enhanced Carbon Nanotube Ultracapacitors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation utilizes carbon nanotubes (CNTs) coated with pseudo-capacitive MnO2 material as nano-composite electrode and ionic electrolyte for the...

  2. Hydrothermal carbonization of waste biomass

    OpenAIRE

    Basso, Daniele

    2016-01-01

    Hydrothermal carbonization (in acronym, HTC) is a thermochemical conversion process through which it is possible to directly transform wet organic substrates into a carbonaceous material, referred as hydrochar. Hydrochar has chemical and physical characteristics that make it similar to fossil peats and lignite. Depending on the process conditions, mostly temperature and residence time, this material can be enriched in its carbon content, modifying its structure and providing it interesting ch...

  3. The Carbon Budget of California

    Science.gov (United States)

    Potter, C. S.

    2009-12-01

    The carbon budget of a region can be defined as the sum of annual fluxes of carbon dioxide and methane greenhouse gases (GHGs) into and out of the regional surface coverage area. According to the state government’s recent inventory, California's carbon budget is presently dominated by fossil fuel emissions of CO2 (at >85% of total annual GHG emissions) to meet energy and transportation requirements. Other notable (non-ecosystem) sources of carbon GHG emissions in 2004 were from cement- and lime-making industries, livestock-based agriculture, and waste treatment activities. The NASA-CASA (Carnegie Ames Stanford Approach) simulation model based on satellite observations of monthly vegetation cover (including those from the Moderate Resolution Imaging Spectroradiometer - MODIS) has been used to estimate net ecosystem fluxes and vegetation biomass production over the period 1990-2004. California's annual NPP for all ecosystems in the early 2000s, estimated by CASA at 120 million metric tons of carbon equivalent (MMTCE) per year, was roughly equal to its annual fossil fuel emission rates for carbon. However, since natural ecosystems can accumulate only a small fraction of this annual NPP total in long-term storage pools, the net ecosystem sink flux for atmospheric carbon across the state was estimated at a maximum rate of between 15-24 MMTCE per year under favorable precipitation conditions. Under less favorable precipitation conditions, such as those experienced during the early 1990s, ecosystems statewide were estimated to have lost nearly 15 MMTCE per year to the atmosphere. Considering the large amounts of carbon stored in standing biomass of forests, shrublands, and rangelands across the state, the implications of changing climate and land use practices on ecosystems must be factored into the state’s planning to reduce overall GHG emissions.

  4. CARBONIZER TESTS WITH LAKELAND FEEDSTOCKS

    Energy Technology Data Exchange (ETDEWEB)

    C. Lu; Z. Fan; R. Froehlich; A. Robertson

    2003-09-01

    Research has been conducted under United States Department of Energy Contract (USDOE) DE-AC21-86MC21023 to develop a new type of coal-fired plant for electric power generation. This new type of plant, called a Second Generation Pressurized Fluidized Bed Combustion Plant (2nd Gen PFB), offers the promise of efficiencies greater than 48%, with both emissions and a cost of electricity that are significantly lower than those of conventional pulverized coal-fired (PC) plants with wet flue gas desulfurization/scrubbers. The 2nd Gen PFB plant incorporates the partial gasification of coal in a carbonizer, the combustion of carbonizer char in a pressurized circulating fluidized (PCFB) bed boiler, and the combustion of carbonizer syngas in a topping combustor to achieve gas turbine inlet temperatures of 2700 F and higher. Under the USDOE Clean Coal V Demonstration Plant Program, a nominal 260 MWe plant demonstrating 2nd Gen PFB technology has been proposed for construction at the McIntosh Power Plant of the City of Lakeland, Florida. In the September-December 1997 time period, four test runs were conducted in Foster Wheeler's 12-inch diameter carbonizer pilot plant in Livingston New Jersey to ascertain carbonizer performance characteristics with the Kentucky No. 9 coal and Florida limestone proposed for use in the Lakeland plant. The tests were of a short-term nature exploring carbonizer carbon conversions, sulfur capture efficiencies and syngas alkali levels. The tests were successful; observed carbonizer performance was in agreement with predictions and no operating problems, attributed to the planned feedstocks, were encountered. The results of the four test runs are reported herein.

  5. Molybdenum Disulfide Sheathed Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Xu Chun SONG; Zhu De XU; Yi Fan ZHENG; Gui HAN; Bo LIU; Wei Xiang CHEN

    2004-01-01

    Single and double layered MoS2-coated multiwalled carbon nanotubes (MWCNs) were successfully prepared by pyrolyzing (NH4)2MoS4-coated multiwalled carbon nanotubes in an H2 atmosphere at 900℃. MoS2-coated MWCNs would be expected to have different tribological and mechanical properties compared to MoS2, so it may have potential applications in many fields.

  6. Permafrost soils and carbon cycling

    OpenAIRE

    Ping, C. L.; J. D. Jastrow; Jorgenson, M. T.; Michaelson, G. J.; Y. L. Shur

    2015-01-01

    Knowledge of soils in the permafrost region has advanced immensely in recent decades, despite the remoteness and inaccessibility of most of the region and the sampling limitations posed by the severe environment. These efforts significantly increased estimates of the amount of organic carbon stored in permafrost-region soils and improved understanding of how pedogenic processes unique to permafrost environments built enormous organic carbon stocks during the Quaternary. This...

  7. Recuperative supercritical carbon dioxide cycle

    Energy Technology Data Exchange (ETDEWEB)

    Sonwane, Chandrashekhar; Sprouse, Kenneth M; Subbaraman, Ganesan; O' Connor, George M; Johnson, Gregory A

    2014-11-18

    A power plant includes a closed loop, supercritical carbon dioxide system (CLS-CO.sub.2 system). The CLS-CO.sub.2 system includes a turbine-generator and a high temperature recuperator (HTR) that is arranged to receive expanded carbon dioxide from the turbine-generator. The HTR includes a plurality of heat exchangers that define respective heat exchange areas. At least two of the heat exchangers have different heat exchange areas.

  8. Carbon storage in Amazonian podzols

    Science.gov (United States)

    Montes, Celia; Lucas, Yves; Pereira, Osvaldo; Merdy, Patricia; Santin, Roberta; Ishida, Débora; du Gardin, Beryl; Melfi, Adolpho

    2014-05-01

    It has recently been discovered that Amazonian podzols may store much larger quantities of carbon than previously thought, particularly in their deep Bh horizons (over 13.6 Pg for Brazilian Amazonia alone [1]). Similarly high carbon stocks are likely to exist in similar climate/soil areas, mainly in Africa and in Borneo. Such carbon stocks raise the problem of their stability in response to changes in land use or climate. Any significant changes in vegetation cover would significantly alter the soil water dynamics, which is likely to affect organic matter turnover in soils. The direction of the change, however, is not clear and is likely to depend on the specific conditions of carbon storage and properties of the soils. It is reasonable to assume that the drying of the Bh horizons of equatorial podzols, which are generally saturated, will lead to an increase in C mineralization, although the extent of this increase has not yet been determined. These unknowns resulted in research programs, granted by the Brazilian FAPESP and the French Région PACA-ARCUS and ANR, dedicated improving estimates of the Amazonian podzol carbon stocks and to an estimate of its mineralisability. Eight test areas were determined from the analysis of remote sensing data in the larger Amazonian podzol region located in the High Rio Negro catchment and studied in detail. Despite the extreme difficulties in carrying out the field work (difficulties in reaching the study sites and extracting the soils), more than a hundred points were sampled. In all podzols the presence of a thick deep Bh was confirmed, sometimes to depths greater than 12 m. The Bh carbon was quantified, indicating that carbon stocks in these podzols are even higher than estimated recently [1]. References 1- Montes, C.R.; Lucas, Y.; Pereira, O.J.R.; Achard, R.; Grimaldi, M.; Mefli, A.J. Deep plant?derived carbon storage in Amazonian podzols. Biogeosciences, 8, 113?120, 2011.

  9. Carbon nanotubes for coherent spintronics

    Directory of Open Access Journals (Sweden)

    F. Kuemmeth

    2010-03-01

    Full Text Available Carbon nanotubes bridge the molecular and crystalline quantum worlds, and their extraordinary electronic, mechanical and optical properties have attracted enormous attention from a broad scientific community. We review the basic principles of fabricating spin-electronic devices based on individual, electrically-gated carbon nanotubes, and present experimental efforts to understand their electronic and nuclear spin degrees of freedom, which in the future may enable quantum applications.

  10. Lithographically defined microporous carbon structures

    Science.gov (United States)

    Burckel, David Bruce; Washburn, Cody M.; Polsky, Ronen; Brozik, Susan M.; Wheeler, David R.

    2013-01-08

    A lithographic method is used to fabricate porous carbon structures that can provide electrochemical electrodes having high surface area with uniform and controllable dimensions, providing enormous flexibility to tailor the electrodes toward specific applications. Metal nanoparticles deposited on the surface of the porous carbon electrodes exhibit ultra small dimensions with uniform size distribution. The resulting electrodes are rugged, electrically conductive and show excellent electrochemical behavior.

  11. Selective functionalization of carbon nanotubes

    Science.gov (United States)

    Strano, Michael S. (Inventor); Usrey, Monica (Inventor); Barone, Paul (Inventor); Dyke, Christopher A. (Inventor); Tour, James M. (Inventor); Kittrell, W. Carter (Inventor); Hauge, Robert H. (Inventor); Smalley, Richard E. (Inventor)

    2009-01-01

    The present invention is directed toward methods of selectively functionalizing carbon nanotubes of a specific type or range of types, based on their electronic properties, using diazonium chemistry. The present invention is also directed toward methods of separating carbon nanotubes into populations of specific types or range(s) of types via selective functionalization and electrophoresis, and also to the novel compositions generated by such separations.

  12. Carbon nanotubes for coherent spintronics

    DEFF Research Database (Denmark)

    Kuemmeth, Ferdinand; Churchill, H O H; Herring, P K;

    2010-01-01

    Carbon nanotubes bridge the molecular and crystalline quantum worlds, and their extraordinary electronic, mechanical and optical properties have attracted enormous attention from a broad scientific community. We review the basic principles of fabricating spin-electronic devices based on individual......, electrically-gated carbon nanotubes, and present experimental efforts to understand their electronic and nuclear spin degrees of freedom, which in the future may enable quantum applications....

  13. Legislators Urge Carbon Emissions Cuts

    Science.gov (United States)

    Kumar, Mohi

    2007-02-01

    Legislators from the world's largest carbon dioxide (CO2) emitting countries met on 14-15 February in Washington, D.C., to discuss the future of the global climate and strategies to mitigate temperature increases resulting from global warming. The world faces a ``double challenge-how to reduce damaging carbon emissions while still meeting the energy demand that the world's poor need to escape poverty,'' said World Bank President Paul Wolfowitz during a keynote talk.

  14. Carbon sequestration in leaky reservoirs

    OpenAIRE

    Jean-Marie, Alain; MOREAUX Michel; Tidball, Mabel

    2011-01-01

    PDF file identical to the paper submitted (available online at the conference site) with authors and affiliations added. International audience We propose in this paper a model of optimal Carbon Capture and Storage in which the reservoir of sequestered carbon is leaky, and pollution eventually is released into the atmosphere. We formulate the social planner problem as an optimal control program and we describe the optimal consumption paths as a function of the initial conditions, the ph...

  15. Toward transformational carbon capture systems

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States); Litynski, John T. [Office of Fossil Energy, U.S. Dept. of Energy, Washington DC (United States); Brickett, Lynn A. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States); Morreale, Bryan D. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States)

    2015-10-28

    This paper will briefly review the history and current state of Carbon Capture and Storage (CCS) research and development and describe the technical barriers to carbon capture. it will argue forcefully for a new approach to R&D, which leverages both simulation and physical systems at the laboratory and pilot scales to more rapidly move the best technoogies forward, prune less advantageous approaches, and simultaneously develop materials and processes.

  16. Sequestration of Soil Carbon as Secondary Carbonates (Invited)

    Science.gov (United States)

    Lal, R.

    2013-12-01

    Rattan Lal Carbon Management and Sequestration Center The Ohio State University Columbus, OH 43210 USA Abstract World soils, the major carbon (C) reservoir among the terrestrial pools, contain soil organic C (SOC) and soil inorganic C (SIC). The SIC pool is predominant in soils of arid and semi-arid regions. These regions cover a land area of about 4.9x109 ha. The SIC pool in soils containing calcic and petrocalcic horizons is estimated at about 695-748 Pg (Pg = 1015 g = 1 gigaton) to 1-m depth. There are two types of carbonates. Lithogenic or primary carbonates are formed from weathering of carbonaceous rocks. Pedogenic or secondary carbonates are formed by dissolution of CO2 in the soil air to form carbonic acid and precipitation as carbonates of Ca+2 or Mg+2. It is the availability of Ca+2 or Mg+2 from outside the ecosystem that is essential to sequester atmospheric CO2. Common among outside sources of Ca+2 or Mg+2 are irrigation water, aerial deposition, sea breeze, fertilizers, manure and other amendments. The decomposition of SOC and root respiration may increase the partial pressure of CO2 in the soil air and lead to the formation of HCO_3^- upon dissolution in H20. Precipitation of secondary carbonates may result from decreased partial pressure of CO2 in the sub-soil, increased concentration of Ca+2, Mg+2 and HCO_3^- in soil solution, and decreased soil moisture content by evapotranspiration. Transport of bicarbonates in irrigated soils and subsequent precipitation above the ground water (calcrete), activity of termites and other soil fauna, and management of urban soils lead to formation of secondary carbonates. On a geologic time scale, weathering of silicate minerals and transport of the by-products into the ocean is a geological process of sequestration of atmospheric CO2. Factors affecting formation of secondary carbonates include land use, and soil and crop management including application of biosolids, irrigation and the quality of irrigation water

  17. Carbon-enhanced VRLA batteries.

    Energy Technology Data Exchange (ETDEWEB)

    Enos, David George; Hund, Thomas D.; Shane, Rod (East Penn Manufacturing, Lyon Station, PA)

    2010-10-01

    The addition of certain forms of carbon to the negative plate in valve regulated lead acid (VRLA) batteries has been demonstrated to increase the cycle life of such batteries by an order of magnitude or more under high-rate, partial-state-of-charge operation. Such performance will provide a significant impact, and in some cases it will be an enabling feature for applications including hybrid electric vehicles, utility ancillary regulation services, wind farm energy smoothing, and solar photovoltaic energy smoothing. There is a critical need to understnd how the carbon interacts with the negative plate and achieves the aforementioned benefits at a fundamental level. Such an understanding will not only enable the performance of such batteries to be optimzied, but also to explore the feasibility of applying this technology to other battery chemistries. In partnership with the East Penn Manufacturing, Sandia will investigate the electrochemical function of the carbon and possibly identify improvements to its anti-sulfation properties. Shiomi, et al. (1997) discovered that the addition of carbon to the negative active material (NAM) substantially reduced PbSO{sub 4} accumulation in high rate, partial state of charge (HRPSoC) cycling applications. This improved performance with a minimal cost. Cycling applications that were uneconomical for traditional VRLA batteries are viable for the carbon enhanced VRLA. The overall goal of this work is to quantitatively define the role that carbon plays in the electrochemistry of a VRLA battery.

  18. Pyrolytic carbon coated black silicon.

    Science.gov (United States)

    Shah, Ali; Stenberg, Petri; Karvonen, Lasse; Ali, Rizwan; Honkanen, Seppo; Lipsanen, Harri; Peyghambarian, N; Kuittinen, Markku; Svirko, Yuri; Kaplas, Tommi

    2016-01-01

    Carbon is the most well-known black material in the history of man. Throughout the centuries, carbon has been used as a black material for paintings, camouflage, and optics. Although, the techniques to make other black surfaces have evolved and become more sophisticated with time, carbon still remains one of the best black materials. Another well-known black surface is black silicon, reflecting less than 0.5% of incident light in visible spectral range but becomes a highly reflecting surface in wavelengths above 1000 nm. On the other hand, carbon absorbs at those and longer wavelengths. Thus, it is possible to combine black silicon with carbon to create an artificial material with very low reflectivity over a wide spectral range. Here we report our results on coating conformally black silicon substrate with amorphous pyrolytic carbon. We present a superior black surface with reflectance of light less than 0.5% in the spectral range of 350 nm to 2000 nm. PMID:27174890

  19. Hydrogen adsorption in carbon nanostructures compared

    NARCIS (Netherlands)

    Schimmel, H.G.; Nijkamp, M.G.; Kearley, G.J.; Rivera, A.; de Jong, K.P.; Mulder, F.M.

    2004-01-01

    Recent reports continue to suggest high hydrogen storage capacities for some carbon nanostructures due to a stronger interaction between hydrogen and carbon. Here the interaction of hydrogen with activated charcoal, carbon nanofibers, single walled carbon nanotubes (SWNT), and electron beam ‘opened’

  20. Rhodium-catalyzed restructuring of carbon frameworks.

    Science.gov (United States)

    Murakami, Masahiro

    2010-10-01

    Metal-catalyzed reactions involving an elementary step which cleaves a carbon-carbon bond provide unique organic transformations. Restructuring reactions recently developed in our laboratory, through which the carbon framework of a starting substance is restructured into a totally different carbon framework, are discussed, with the possibility of applying such methods to the synthesis of natural products.

  1. Carbon Fiber from Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Milbrandt, Anelia [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States); Booth, Samuel [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States)

    2016-09-01

    Carbon fiber (CF), known also as graphite fiber, is a lightweight, strong, and flexible material used in both structural (load-bearing) and non-structural applications (e.g., thermal insulation). The high cost of precursors (the starting material used to make CF, which comes predominately from fossil sources) and manufacturing have kept CF a niche market with applications limited mostly to high-performance structural materials (e.g., aerospace). Alternative precursors to reduce CF cost and dependence on fossil sources have been investigated over the years, including biomass-derived precursors such as rayon, lignin, glycerol, and lignocellulosic sugars. The purpose of this study is to provide a comprehensive overview of CF precursors from biomass and their market potential. We examine the potential CF production from these precursors, the state of technology and applications, and the production cost (when data are available). We discuss their advantages and limitations. We also discuss the physical properties of biomass-based CF, and we compare them to those of polyacrylonitrile (PAN)-based CF. We also discuss manufacturing and end-product considerations for bio-based CF, as well as considerations for plant siting and biomass feedstock logistics, feedstock competition, and risk mitigation strategies. The main contribution of this study is that it provides detailed technical and market information about each bio-based CF precursor in one document while other studies focus on one precursor at a time or a particular topic (e.g., processing). Thus, this publication allows for a comprehensive view of the CF potential from all biomass sources and serves as a reference for both novice and experienced professionals interested in CF production from alternative sources.

  2. Yeast Carbon Catabolite Repression†

    Science.gov (United States)

    Gancedo, Juana M.

    1998-01-01

    Glucose and related sugars repress the transcription of genes encoding enzymes required for the utilization of alternative carbon sources; some of these genes are also repressed by other sugars such as galactose, and the process is known as catabolite repression. The different sugars produce signals which modify the conformation of certain proteins that, in turn, directly or through a regulatory cascade affect the expression of the genes subject to catabolite repression. These genes are not all controlled by a single set of regulatory proteins, but there are different circuits of repression for different groups of genes. However, the protein kinase Snf1/Cat1 is shared by the various circuits and is therefore a central element in the regulatory process. Snf1 is not operative in the presence of glucose, and preliminary evidence suggests that Snf1 is in a dephosphorylated state under these conditions. However, the enzymes that phosphorylate and dephosphorylate Snf1 have not been identified, and it is not known how the presence of glucose may affect their activity. What has been established is that Snf1 remains active in mutants lacking either the proteins Grr1/Cat80 or Hxk2 or the Glc7 complex, which functions as a protein phosphatase. One of the main roles of Snf1 is to relieve repression by the Mig1 complex, but it is also required for the operation of transcription factors such as Adr1 and possibly other factors that are still unidentified. Although our knowledge of catabolite repression is still very incomplete, it is possible in certain cases to propose a partial model of the way in which the different elements involved in catabolite repression may be integrated. PMID:9618445

  3. Scale-up of Carbon/Carbon Bipolar Plates

    Energy Technology Data Exchange (ETDEWEB)

    David P. Haack

    2009-04-08

    This project was focused upon developing a unique material technology for use in PEM fuel cell bipolar plates. The carbon/carbon composite material developed in this program is uniquely suited for use in fuel cell systems, as it is lightweight, highly conductive and corrosion resistant. The project further focused upon developing the manufacturing methodology to cost-effectively produce this material for use in commercial fuel cell systems. United Technology Fuel Cells Corp., a leading fuel cell developer was a subcontractor to the project was interested in the performance and low-cost potential of the material. The accomplishments of the program included the development and testing of a low-cost, fully molded, net-shape carbon-carbon bipolar plate. The process to cost-effectively manufacture these carbon-carbon bipolar plates was focused on extensively in this program. Key areas for cost-reduction that received attention in this program was net-shape molding of the detailed flow structures according to end-user design. Correlations between feature detail and process parameters were formed so that mold tooling could be accurately designed to meet a variety of flow field dimensions. A cost model was developed that predicted the cost of manufacture for the product in near-term volumes and long-term volumes (10+ million units per year). Because the roduct uses lowcost raw materials in quantities that are less than competitive tech, it was found that the cost of the product in high volume can be less than with other plate echnologies, and can meet the DOE goal of $4/kW for transportation applications. The excellent performance of the all-carbon plate in net shape was verified in fuel cell testing. Performance equivalent to much higher cost, fully machined graphite plates was found.

  4. The role of carbon in the photocatalytic reaction of carbon/TiO{sub 2} photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Feng; Zhang, Guozhi; Wang, Youqing; Gao, Caitian; Chen, Lulu; Zhang, Peng; Zhang, Zhenxing, E-mail: zhangzx@lzu.edu.cn; Xie, Erqing, E-mail: xieeq@lzu.edu.cn

    2014-11-30

    Graphical abstract: - Highlights: • Carbon/TiO{sub 2} composites were fabricated by one-step carbonization method. • Carbon was generated by the dehydration carbonation effect of polymers. • Carbon was formed inside and outside of the TiO{sub 2} nanoparticles. • The photocatalytic activities of the composites depend on the coating carbon. - Abstract: The carbon/TiO{sub 2} nanocomposites were fabricated by a simple one-step carbonization method with different polymers as precursors. Due to the dehydration carbonation effect of polymers, carbon was formed inside and outside of the TiO{sub 2} nanoparticles. The photo-degradation study of rhodamine B was carried out under UV–vis light irradiation, and the photocatalytic activities of carbon/TiO{sub 2} nanocomposites are affected severely by the state of carbon, including dopants and coatings. The results show that the carbon on the surface plays more important role in the photocatalytic process.

  5. Carbon Fiber Reinforced Carbon Composite Valve for an Internal Combustion Engine

    Science.gov (United States)

    Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor)

    1999-01-01

    A carbon fiber reinforced carbon composite valve for internal combustion engines and the like formed of continuous carbon fibers throughout the valve's stem and head is disclosed. The valve includes braided carbon fiber material over axially aligned unidirectional carbon fibers forming a valve stem; the braided and unidirectional carbon fibers being broomed out at one end of the valve stem forming the shape of the valve head; the valve-shaped structure being densified and rigidized with a matrix of carbon containing discontinuous carbon fibers: and the finished valve being treated to resist oxidation. Also disclosed is a carbon matrix plug containing continuous and discontinuous carbon fibers and forming a net-shape valve head acting as a mandrel over which the unidirectional and braided carbon fibers are formed according to textile processes. Also disclosed are various preform valves and processes for making finished and preform carbon fiber reinforced carbon composite valves.

  6. Adsorption over polyacrylonitrile based carbon monoliths

    Science.gov (United States)

    Nandi, Mahasweta; Dutta, Arghya; Patra, Astam Kumar; Bhaumik, Asim; Uyama, Hiroshi

    2013-02-01

    Highly porous activated carbon monoliths have been prepared from mesoporous polyacrylonitrile (PAN) monolith as the carbon precursor. The mesoporous PAN monoliths are fabricated by a unique and facile template-free method which on carbonization gives N-doped activated carbon monoliths. The carbonization is achieved via two step thermal process which includes pretreatment in air leading to cyclization and subsequent aromatization of the PAN moieties followed by carbonization in a mixture of argon and carbon dioxide to give a layered carbon framework. Nitrogen sorption experiments carried over these carbon monoliths revealed high surface area (ca. 2500 m2g-1) for these materials with precise micropore size distribution. The activated carbons show extraordinarily high CO2 capture capacity and the uptake up to 3 bar has been found to be as high as 22.5 and 10.6 mmol/g at 273 K and 298 K, respectively.

  7. Characterization and Damage Evaluation of Coal Tar Pitch Carbon Matrix Used in Carbon/Carbon Composites

    Science.gov (United States)

    Bhagat, Atul Ramesh; Mahajan, Puneet

    2016-09-01

    Flexure, compressive, and shear properties of the carbon matrix in carbon/carbon (C/C) composites made via a pitch impregnation method have been determined. The pitch carbon matrix was made using the same densification cycle used in making the C/C composite. Cyclic compression tests were performed on the matrix specimens. While unloading, a reduction in modulus was observed and residual strains were observed on complete unloading. These features were attributed to the presence of damage and plasticity in the densified matrix. A J 2 plasticity model with damage was used to simulate this behavior numerically. The parameters required for plasticity and damage model were evaluated iteratively by comparing the results in experiments with simulation.

  8. Gravimetric Determination of Inorganic Carbon in Calcareous Soils Using the Carbonate-Meter

    Science.gov (United States)

    Organic carbon affects many important physical, chemical and microbiological soil properties. In calcareous soils, the inorganic carbon has to be measured and subtracted from the total carbon to obtain organic carbon. Our objective was to develop a gravimetric technique to quantify inorganic carbon ...

  9. The significance of carbon-enriched dust for global carbon accounting

    Science.gov (United States)

    Soil carbon stores amount to 54% of the terrestrial carbon pool and twice the atmospheric carbon pool, but soil organic carbon (SOC) can be transient. There is an ongoing debate about whether soils are a net source or sink of carbon, and understanding the role of aeolian processes in SOC erosion, tr...

  10. 75 FR 29534 - Inorganic Nitrates-Nitrite, Carbon and Carbon Dioxide, and Sulfur Registration Review; Draft...

    Science.gov (United States)

    2010-05-26

    ... AGENCY Inorganic Nitrates-Nitrite, Carbon and Carbon Dioxide, and Sulfur Registration Review; Draft... draft ecological risk assessment for the registration review of inorganic nitrates - nitrites, carbon... occur for all inorganic nitrates- nitrites, carbon and carbon dioxide uses, as well as gas...

  11. Carbonic Acid Retreatment of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Baylor university

    2003-06-01

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. (1) Solidify the theoretical understanding of the binary CO{sub 2}/H{sub 2}O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. (2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. (3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. (4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. (5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for

  12. Carbonic Acid Pretreatment of Biomass

    Energy Technology Data Exchange (ETDEWEB)

    G. Peter van Walsum; Kemantha Jayawardhana; Damon Yourchisin; Robert McWilliams; Vanessa Castleberry

    2003-05-31

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic

  13. Preparation of very pure active carbon

    International Nuclear Information System (INIS)

    The preparation of very pure active carbon is described. Starting from polyvinylidene chloride active carbon is prepared by carbonization in a nitrogen atmosphere, grinding, sieving and activation of the powder fraction with CO2 at 9500 to approximately 50% burn-off. The concentrations of trace and major elements are reduced to the ppb and ppm level, respectively. In the present set-up 100 g of carbon grains and approximately 50 g of active carbon powder can be produced weekly

  14. Carbonated concrete blocks for CO2 captation

    OpenAIRE

    Courard, Luc; Parmentier, Véronique; Michel, Frédéric

    2015-01-01

    The CO2 captation process called carbonation, improves specific properties of the concrete during the conversion of carbon dioxide CO2 into calcium carbonate CaCO3. Current environmental concerns motivate the study of carbonation in order to maximize the absorption of carbon dioxide. Moreover, lightweight concrete with bio-based products knows an interesting development in the construction field, especially as thermal insulation panels for walls in buildings. Concrete blocks produced with mis...

  15. Sustainable carbon materials from hydrothermal processes

    CERN Document Server

    Titirici, Maria-Magdalena

    2013-01-01

    The production of low cost and environmentally friendly high performing carbon materials is crucial for a sustainable future. Sustainable Carbon Materials from Hydrothermal Processes describes a sustainable and alternative technique to produce carbon from biomass in water at low temperatures, a process known as Hydrothermal Carbonization (HTC). Sustainable Carbon Materials from Hydrothermal Processes presents an overview of this new and rapidly developing field, discussing various synthetic approaches, characterization of the final products, and modern fields of application fo

  16. Rangelands: a closing carbon sink?

    Science.gov (United States)

    Kuhn, Nikolaus J.

    2016-04-01

    Two thirds of the world's agricultural land is suitable for grazing only. Much of this land has experienced severe erosion due to mismanagement, massive redistribution of soil and sediment, and significant degradation of vegetation. As a consequence, geochemical cycles have changed. Unlike croplands, the impact of degradation on nutrient fluxes is hardly compensated on rangelands, potentially disturbing the carbon cycle because of the declining biomass production and the subsequent conversion of litter into soil organic matter. Over time, the degradation leads to a decline in soil C stocks and, if associated with soil erosion, also to a decline in carbon transfer from soil into sediment sinks. A priory reasoning suggests that during the degradation process, with soil productivity not yet massively affected, the Carbon transfer initially increases because soil erosion rates are also greater than in the non-disturbed system. With most soil degradation in rangelands occurring during the past 200 years, this mechanism on a large part of the global land area could have generated an unintentional terrestrial carbon sink during a time period with increasing industrial CO2 emissions. Using global data on soil degradation, soil erosion, soil carbon stocks and dynamics to simulate their interaction and potential role for rangeland carbon cycles supports the assumption that rangelands may have functioned as a carbon sink, but reveals major uncertainties with regards to the size. This highlights the need to improve our knowledge and understanding of rangeland erosion, landscape change and soil formation, both with regards to the recent past, but also the impacts of their future use and climate.

  17. Reducing carbon-in-ash

    Energy Technology Data Exchange (ETDEWEB)

    Nigel S. Dong [IEA Clean Coal Centre, London (United Kingdom)

    2010-05-15

    High levels of carbon-in-ash lead to reduced power plant efficiency and higher fuel costs, degrade the performance of electrostatic precipitators and increase emissions of particulates. Increased carbon levels in the fly ash can lead to problems with ash use in cement/concrete production. This report reviews current measures and technologies that can be used to prevent excessive carbon-in-ash in pulverised coal combustion (PCC) power plants. These include coal cleaning, coal fineness improvement, reduction of distribution imbalance of coal among burners, increasing coal-air mixing rates at both burner and OFA levels and optimising excess air ratios. A plasma-assisted combustion enhancement technology can help achieve better ignition and more stable flame for coals that are normally difficult to burn. Computer-based combustion optimisation using expert systems, neural network systems and coal combustion simulation is becoming an invaluable means to tackle the carbon-in-ash issue. This report also reviews the regulations in nine major coal-consuming countries, which stipulate the maximum unburnt carbon levels permitted for fly ash for use in concrete/cement production. The Loss on Ignition (LOI) parameter is used in all national standards, although it is considered inadequate and may exclude some usable fly ash from being utilised. Performance-based regulations are more appropriate and have been adopted by Canada and USA. The EU and Canada now permit the use of fly ash produced from co-combustion of coal and biomass. China and Russia allow very high LOI levels for certain fly ash but the other countries require similar LOI limits for fly ash for use in concrete. Finally, this report discusses measures and technologies for reduction of carbon-in-ash, including classification, froth flotation, triboelectrostatic separators, thermal processes and carbon surface modification. 146 refs., 19 figs., 15 tabs.

  18. The carbon budget of California

    International Nuclear Information System (INIS)

    The carbon budget of a region can be defined as the sum of annual fluxes of carbon dioxide (CO2) and methane (CH4) greenhouse gases (GHGs) into and out of the regional surface coverage area. According to the state government's recent inventory, California's carbon budget is presently dominated by 115 MMTCE per year in fossil fuel emissions of CO2 (>85% of total annual GHG emissions) to meet energy and transportation requirements. Other notable (non-ecosystem) sources of carbon GHG emissions in 2004 were from cement- and lime-making industries (7%), livestock-based agriculture (5%), and waste treatment activities (2%). The NASA-CASA (Carnegie Ames Stanford Approach) simulation model based on satellite observations of monthly vegetation cover (including those from the Moderate Resolution Imaging Spectroradiometer, MODIS) was used to estimate net ecosystem fluxes and vegetation biomass production over the period 1990-2004. California's annual NPP for all ecosystems in the early 2000s (estimated by CASA at 120 MMTCE per year) was roughly equivalent to its annual fossil fuel emission rates for carbon. However, since natural ecosystems can accumulate only a small fraction of this annual NPP total in long-term storage pools, the net ecosystem sink flux for atmospheric carbon across the state was estimated at a maximum rate of about 24 MMTCE per year under favorable precipitation conditions. Under less favorable precipitation conditions, such as those experienced during the early 1990s, ecosystems statewide were estimated to have lost nearly 15 MMTCE per year to the atmosphere. Considering the large amounts of carbon estimated by CASA to be stored in forests, shrublands, and rangelands across the state, the importance of protection of the natural NPP capacity of California ecosystems cannot be overemphasized.

  19. The Megacities Carbon Project: measuring urban carbon emissions

    Science.gov (United States)

    Duren, R. M.; Kort, E. A.; Miller, C. E.

    2012-12-01

    Carbon emissions from cities represent the single largest human contribution to climate change. Robust verification of emission changes due to growth or stabilization policies requires that we establish measurement baselines today and begin monitoring representative megacities immediately. An observing system designed to monitor the localized enhancements ("urban domes") of carbon dioxide and methane associated with cities must include a tiered set of surface, airborne, and satellite sensors and a framework for integrating top-down (atmospheric) and bottom-up (activity) data. We present a vision, strategy, requirements, and roadmap for an international effort to assess directly the carbon emission trends of the world's megacities. We describe a new coordinated pilot project for the megacities of Los Angeles and Paris that leverages and extends established measurement infrastructure in those cities and techniques being developed in methodological studies of smaller cities.

  20. PREPARATION OF MESOPOROUS CARBON BY CARBON DIOXIDE ACTIVATION WITH CATALYST

    Institute of Scientific and Technical Information of China (English)

    W.Z.Shen; A.H.Lu; J.T.Zheng

    2002-01-01

    A mesoporous activated carbon (AC) can be successfully prepared by catalytic activa-tion with carbon dioxide. For iron oxide as catalyst, there were two regions of mesoporesize distribution, i.e. 2-5nm and 30-70nm. When copper oxide or magnesium oxidecoexisted with iron oxide as composite catalyst, the content of pores with sizes of 2-5nm was decreased, while the pores with 30 70nm were increased significantly. Forcomparison, AC reactivated by carbon dioxide directly was also investigated. It wasshown that the size of mesopores of the resulting AC concentrated in 2-5nm with lessvolume. The adsorption of Congo red was tested to evaluate the property of the result-ing AC. Furthermore, the factors affecting pore size distribution and the possibility ofmesopore formation were discussed.

  1. Detection of Carbon Monoxide Using Polymer-Carbon Composite Films

    Science.gov (United States)

    Homer, Margie L.; Ryan, Margaret A.; Lara, Liana M.

    2011-01-01

    A carbon monoxide (CO) sensor was developed that can be incorporated into an existing sensing array architecture. The CO sensor is a low-power chemiresistor that operates at room temperature, and the sensor fabrication techniques are compatible with ceramic substrates. Sensors made from four different polymers were tested: poly (4-vinylpryridine), ethylene-propylene-diene-terpolymer, polyepichlorohydrin, and polyethylene oxide (PEO). The carbon black used for the composite films was Black Pearls 2000, a furnace black made by the Cabot Corporation. Polymers and carbon black were used as received. In fact, only two of these sensors showed a good response to CO. The poly (4-vinylpryridine) sensor is noisy, but it does respond to the CO above 200 ppm. The polyepichlorohydrin sensor is less noisy and shows good response down to 100 ppm.

  2. Novel method for carbon nanofilament growth on carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Johathan [Los Alamos National Laboratory; Luhrs, Claudia [UNM MECH.ENG.; Terani, Mehran [UNM MECH.ENG.; Al - Haik, Marwan [UNM MECH.ENG.; Garcia, Daniel [UNM MECH.ENG.; Taha, Mahmoud R [UNM MECH.ENG.

    2009-01-01

    Fiber reinforced structural composites such as fiber reinforced polymers (FRPs) have proven to be key materials for blast mitigation due to their enhanced mechanical performance. However, there is a need to further increase total energy absorption of the composites in order to retain structural integrity in high energy environments, for example, blast events. Research has shown that composite failure in high energy environments can be traced to their relatively low shear strength attributed to the limited bond strength between the matrix and the fibers. One area of focus for improving the strength of composite materials has been to create 'multi-scale' composites. The most common approach to date is to introduce carbon nanotubes into a more traditional composite consisting of epoxy with embedded micron scale fibers. The inclusion of carbon nanotubes (CNT) clearly toughens different matrices. Depositing CNT in brittle matrix increases stiffness by orders of magnitude. Currently, this approach to create multiscale composites is limited due to the difficulty of dispersing significant amounts of nanotubes. It has repeatedly been reported that phase separation occurs above relatively low weight percent loading (ca. 3%) due to the strong van der Waals forces between CNTs compared with that between CNT and polymer. Hence, the nanotubes tend to segregate and form inclusions. One means to prevent nanotube or nanofilament agglomeration is to anchor one end of the nanostructure, thereby creating a stable multi-phase structure. This is most easily done by literally growing the CNTs directly on micron scale fibers. Recently, CNT were grown on carbon fibers, both polyacrylonitrile- (PAN-) and pitch-based, by hot filament chemical vapor deposition (HFCVD) using H2 and CH4 as precursors. Nickel clusters were electrodeposited on the fiber surfaces to catalyze the growth and uniform CNT coatings were obtained on both the PAN- and pitch-based carbon fibers. Multiwalled CNTs

  3. Yeast-based microporous carbon materials for carbon dioxide capture.

    Science.gov (United States)

    Shen, Wenzhong; He, Yue; Zhang, Shouchun; Li, Junfen; Fan, Weibin

    2012-07-01

    A hierarchical microporous carbon material with a Brunauer-Emmett-Teller surface area of 1348 m(2) g(-1) and a pore volume of 0.67 cm(3) g(-1) was prepared from yeast through chemical activation with potassium hydroxide. This type of material contains large numbers of nitrogen-containing groups (nitrogen content >5.3 wt%), and, consequently, basic sites. As a result, this material shows a faster adsorption rate and a higher adsorption capacity of CO(2) than the material obtained by directly carbonizing yeast under the same conditions. The difference is more pronounced in the presence of N(2) or H(2)O, showing that chemical activation of discarded yeast with potassium hydroxide could afford high-performance microporous carbon materials for the capture of CO(2).

  4. Carbon fiber-reinforced carbon as a potential implant material.

    Science.gov (United States)

    Adams, D; Williams, D F; Hill, J

    1978-01-01

    A carbon fiber-reinforced carbon is being evaluated as a promising implant material. In a unidirectional composite, high strengths (1200 MN/m2 longitudinal flexural strength) and high modulus (140 GN/m2 flexural modulus) may be obtained with an interlaminar shear strength of 18 MN/m2. Alternatively, layers of fibers may be laid in two directions to give more isotopic properties. The compatibility of the material with bone has been studied by implanting specimens in holes drilled in rat femora. For a period of up to 8 weeks, a thin layer of fibrous tissue bridged the gap between bone and implant; but this tissue mineralizes and by 10 weeks, bone can be observed adjacent to the implant, giving firm fixation. Potential applications include endosseous dental implants where a greater strength in the neck than that provided by unreinforced carbon would be advantageous.

  5. Rationalizing Burned Carbon with Carbon Monoxide Exported from South America

    Science.gov (United States)

    Chatfield, R.; Freitas, S. R.; SilvaDias, M. A.; SilvaDias, P. O.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    We present several estimates cross-checking the fluxes of carbon to the atmosphere from burning, comparing models that are based on simple land-surface parameterizations and atmospheric transport dynamics. Both estimates made by NASA Ames and USP modeling techniques are quite high compared to some detailed satellite/land-use studies of emissions. The flux of carbon liberated to the atmosphere via biomass burning is important for several reasons. This flux is a fundamental statistic for the parameterization of the large-scale flux of gases controlling the reactive greenhouse gases methane and ozone. Similarly, it is central to the estimation of the translocation of nitrogen and pyrodenitrification in the tropics. Thirdly, CO2 emitted from rainforest clearing contributes directly to carbon lost from the rainforest system as it contributes to greenhouse gas forcing. While CO2 from pasturage, agriculture, etc, is considered to be reabsorbed seasonally, and so "off budget" for the carbon cycle, it must also be accounted. CO2 anomalies related to daily weather and interannual climatic variation are strong enough to perturb our scientific perception of long-term carbon storage trends. We compare fluxes deduced from land-use statistics (originally, W.M. Hao) and from satellite hot pixels (A. Setzer) with atmospheric fluxes determined by the mesoscale/continental scale models RAMS and MM5, and point to some new work with highly resolved global models (the NASA Data Assimilation Office's GEOS4). Our simulations are tied to events, so that measured tracers like CO tie the models directly to the burning and meteorology of a specific period. We point out a particular sensitivity in estimates based on CO, and indicate how analysis of CO2 along with other biomass-burning tracers may lead to an improved multi-species estimator of carbon burned.

  6. INCCA: Integrated Climate and Carbon

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, S L

    2001-03-13

    The INCCA (Integrated Climate and Carbon) initiative will develop and apply the ability to simulate the fate and climate impact of fossil fuel-derived carbon dioxide (CO{sub 2}) and aerosols on a global scale. Coupled climate and carbon cycle modeling like that proposed for INCCA is required to understand and predict the future environmental impacts of fossil fuel burning. At present, atmospheric CO{sub 2} concentrations are prescribed, not simulated, in large climate models. Credible simulations of the entire climate system, however, need to predict time-evolving atmospheric greenhouse forcing using anthropogenic emissions as the fundamental input. Predicting atmospheric COS concentrations represents a substantial scientific advance because there are large natural sources and sinks of carbon that are likely to change as a result of climate change. Both terrestrial (e.g., vegetation on land) and oceanic components of the carbon cycle are known to be sensitive to climate change. Estimates of the amount of man-made CO{sub 2} that will accumulate in the atmosphere depend on understanding the carbon cycle. For this reason, models that use CO{sub 2} emissions, not prescribed atmospheric concentrations, as fundamental inputs are required to directly address greenhouse-related questions of interest to policymakers. INCCA is uniquely positioned to make rapid progress in this high-priority area of global change modeling and prediction because we can leverage previous and ongoing LLNL developments, and use existing component models that are well-developed and published. The need for a vastly improved carbon dioxide prediction capability is appreciated by the DOE. As the US Accelerated Climate Prediction Initiative (ACPI) progresses, we expect the DOE will emphasize the carbon cycle as the next major department-level earth science focus. INCCA will position LLNL for substantial additional funding as this new focus is realized. In the limited time since our LDRD funding was

  7. Ultrasound-intensified mineral carbonation

    International Nuclear Information System (INIS)

    Several aspects of ultrasound-assisted mineral carbonation were investigated in this work. The objectives were to intensify the CO2 sequestration process to improve reaction kinetics and maximal conversion. Stainless steel slags, derived from the Argon Oxygen Decarburization (AOD) and Continuous Casting/Ladle Metallurgy (CC/LM) refining steps, were used for assessing the technical feasibility of this concept, as they are potential carbon sinks and can benefit from reduction in alkalinity (pH) by mineral carbonation. Ultrasound was applied by use of an ultrasound horn into the reaction slurry, where mineral carbonation reaction took place at 50 °C for up to 4 h; comparison was made to solely mechanically mixed process. It was found that sonication increases the reaction rate after the initial stage, and permits achieving higher carbonate conversion and lower pH. AOD slag conversion increased from 30% to 49%, and pH decreased from 10.6 to 10.1; CC slag conversion increased from 61% to 73% and pH decreased from 10.8 to 9.9. The enhancement effect of ultrasound was attributed to the removal of passivating layers (precipitated calcium carbonate and depleted silica) that surround the unreacted particle core and inhibit mass transfer. Significant particle size reduction was observed for sonicated powders, compared to particle size growth in the case of stirring-only; D[4,3] values increased without sonication by 74% and 50%, and decreased with sonication by 64% and 52%, respectively for AOD and CC slags. Considerations on scale-up of this technology, particularly with regards to energy efficiency, are also discussed. Highlights: ► Ultrasound increased CaO, AOD and CC slags mineral carbonation rates and conversions. ► Enhancement effect linked to removal of mass transfer inhibiting passivating layers. ►Carbonated particle size grew with stirring-only, and decreased with sonication. ► Lower pH of slags with greater carbonation extent can reduce heavy metal leaching

  8. History of ultrahigh carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Wadsworth, J.; Sherby, O.D.

    1997-06-20

    The history and development of ultrahigh carbon steels (i.e., steels containing between 1 and 2.l percent C and now known as UHCS) are described. The early use of steel compositions containing carbon contents above the eutectoid level is found in ancient weapons from around the world. For example, both Damascus and Japanese sword steels are hypereutectoid steels. Their manufacture and processing is of interest in understanding the role of carbon content in the development of modern steels. Although sporadic examples of UHCS compositions are found in steels examined in the early part of this century, it was not until the mid-1970s that the modern study began. This study had its origin in the development of superplastic behavior in steels and the recognition that increasing the carbon content was of importance in developing that property. The compositions that were optimal for superplasticity involved the development of steels that contained higher carbon contents than conventional modern steels. It was discovered, however, that the room temperature properties of these compositions were of interest in their own right. Following this discovery, a period of intense work began on understanding their manufacture, processing, and properties for both superplastic forming and room temperature applications. The development of superplastic cast irons and iron carbides, as well as those of laminated composites containing UHCS, was an important part of this history.

  9. Assessing carbon lock-in

    International Nuclear Information System (INIS)

    The term ‘carbon lock-in’ refers to the tendency for certain carbon-intensive technological systems to persist over time, ‘locking out’ lower-carbon alternatives, and owing to a combination of linked technical, economic, and institutional factors. These technologies may be costly to build, but relatively inexpensive to operate and, over time, they reinforce political, market, and social factors that make it difficult to move away from, or ‘unlock’ them. As a result, by investing in assets prone to lock-in, planners and investors restrict future flexibility and increase the costs of achieving agreed climate protection goals. Here, we develop a straight-forward approach to assess the speed, strength, and scale of carbon lock-in for major energy-consuming assets in the power, buildings, industry, and transport sectors. We pilot the approach at the global level, finding that carbon lock-in is greatest, globally, for coal power plants, gas power plants, and oil-based vehicles. The approach can be readily applied at the national or regional scale, and may be of particular relevance to policymakers interested in enhancing flexibility in their jurisdictions for deeper emissions cuts in the future, and therefore in limiting the future costs associated with ‘stranded assets’. (letter)

  10. Controllable fabrication of carbon aerogels

    Institute of Scientific and Technical Information of China (English)

    FENG Ya'ning; MIAO Lei; TANEMURA Sakae; TANEMURA Masaki; SUZUKI Kenzi

    2006-01-01

    Nano-pore carbon aerogels were prepared by the sol-gel polymerization of resorcinol (1,3-dihydroxybenzene)(C6H4(OH)2) with formaldehyde (HCHO) in a slightly basic aqueous solution, followed by super-critical drying under liquid carbon dioxide as super-critical media and carbonization at 700 ℃ under N2 gas atmosphere. The key of the work is to fabricate carbon aerogels with controllable nano-pore structure, which means extremely high surface area and sharp pore size distribution. Aiming to investigate the effects of preparation conditions on the gelation process, the bulk density, and the physical and chemical structure of the resultant carbon aerogels, the molar ratio of R/C (resorcinol to catalyst) and the amount of distilled water were varied, consequently two different sets of samples, with series of R/C ratio and RF/W (Resorcinol-Formaldehyde to water, or the content of reactant) ratio, were prepared. The result of N2 adsorption/desorption experiment at 77 K shows that the pore sizes decreasing from 11.4 down tO2.2 nm with the increasing of the molar ratio of R/C from 100 to 400, and/or, the pore sizes decreasing from 3.8 down to 1.6 nm with the increasing of reactant content from 0.4 to 0.6.

  11. Deciphering Carbon Isotope Excursions in Separated Biogenic and Diagenetic Carbonates

    Science.gov (United States)

    Hermoso, M.; Minoletti, F.; Hesselbo, S.; Jenkyns, H.; Rickaby, R.; Diester-Haass, L.; Delsate, D.

    2008-12-01

    The long-term evolution of the carbon-isotope ratio in the sedimentary archive is classically linked with changes in primary productivity and organic matter burial. There have been sudden and pronounced shifts, so-called Carbon Isotope Excursions (CIEs) in the long-term trends as evidenced by synchronous shifts from various basins. These geochemical perturbations may have various explanations such as changes of the efficiency of the carbon sink; sudden infusion of isotopically-light carbon into the Ocean-Atmosphere system; or advection of 12C-rich source from bottom water in a stratified water column. Beside the record of primary changes in seawater chemistry, a possible diagenetic overprint may also mime such CIEs in the sedimentary record. The aim of this contribution is to illustrate through three critical intervals (the Early Toarcian, the K-P boundary and the Mid-Miocene Montery Event) how the various micron-sized sedimentary particles specifically record these CIEs, which are respectively associated with major paleoceanographical events. New techniques for getting monotaxic calcareous nannofossil assemblages from the sediment (Minoletti et al., accepted) enable the isotopic measurement at various depths within the surface water and from bottom water by analyzing early diagenetic precipitations (rhombs and micarbs). The integration of these high-resolution isotopic signals in terms of amplitudes affords to recognize diagenetic artifacts in some sections displaying coeval decrease in the carbonate content. For both Early Toarcian and K-P events, corroborative records of CIE records in both primary calcite and bottom water carbonate indicate a global C-isotope perturbation of the water column. For the Monterey event, the evolution of calcareous nannoplankton and the foraminifera isotopic records are in overall agreement, but in detail, the coccolith-discoaster and foraminifer ratio in the sediment, related to environmental changes, is likely to produce isotopic

  12. Preparation of microporous activated carbons based on carbonized apricot shells

    Directory of Open Access Journals (Sweden)

    Vladimir Pavlenko

    2014-10-01

    Full Text Available Results of applying the method of thermo-oxidative modification of fiber, based on the shell of apricot along with producing on its base microporous activated carbons that have high specific surface area and a significant amount of micropores were presented. The paper contains analysis and interpretation data of changes in the structure and composition of samples, which occurring as a result of thermal degradation of lignocellulosic materials. Morphological features of the surface of produced activated carbons were studied by using SEM microscopy; the pore structure and specific surface area were investigated using the method of low-temperature nitrogen adsorption.

  13. An Organocobalt–Carbon Nanotube Chemiresistive Carbon Monoxide Detector

    OpenAIRE

    Liu, Sophie F.; Lin, Sibo; Swager, Timothy M.

    2016-01-01

    A chemiresistive detector for carbon monoxide was created from single-walled carbon nanotubes (SWCNTs) by noncovalent modification with diiodo(η5: η1-1-[2-(N,N-dimethylamino)ethyl]-2,3,4,5-tetramethylcyclopentadienyl)-cobalt(III) ([Cp^CoI2]), an organocobalt complex with an intramolecular amino ligand coordinated to the metal center that is displaced upon CO binding. The unbound amino group can subsequently be transduced chemiresistively by the SWCNT network. The resulting device was shown to...

  14. Activation of Carbon Dioxide and Synthesis of Propylene Carbonate

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Cycloaddition of carbon dioxide and propylene oxide to propylene carbonate catalyzed by tetra-tert-butyl metal phthalocyanine in the presence of tributylamine (TBA) shows higher yield than catalyzed by unsubstituted metal phthalocyanine. Comparing different catalysts of diverse metals, (t-Bu)4PcMg is more active than (t-Bu)4PcFe. But (t-Bu)4PcCo and (t-Bu)4PcNi only have low catalytic activities towards the reaction. Moreover, the yield will increase as the temperature increases.

  15. Carbon Market Regulation Mechanism Research Based on Carbon Accumulation Model with Jump Diffusion

    OpenAIRE

    Dongmei Guo; Yi Hu; Bingjie Zhang

    2014-01-01

    In order to explore carbon market regulation mechanism more effectively, based on carbon accumulation model with jump diffusion, this paper studies the carbon price from two perspectives of quantity instrument and price instrument and quantitatively simulates carbon price regulation mechanisms in the light of actual operation of EU carbon market. The results show that quantity instrument and price instrument both have certain effects on carbon market; according to the comparison of the elasti...

  16. Refining of hydrochars/ hydrothermally carbonized biomass into activated carbons and their applications

    OpenAIRE

    Hao, Wenming

    2014-01-01

    Hydrothermally treated biomass could not only be used as a fuel or a fertilizer but it can also be refined into high-value products. Activated carbons are one of those. In the studies of this thesis, four different hydrothermally carbonized (HTC) biomasses, including horse manure, grass cuttings, beer waste and biosludge, have been successfully made into activated carbons. The activated carbon materials were in the forms of powdered activated carbons, powdered composites of activated carbon a...

  17. Aerobic dehydrogenative α-diarylation of benzyl ketones with aromatics through carbon-carbon bond cleavage.

    Science.gov (United States)

    More, Nagnath Yadav; Jeganmohan, Masilamani

    2014-02-01

    Substituted benzyl ketones reacted with aromatics in the presence of K2S2O8 in CF3COOH at room temperature, yielding α-diaryl benzyl ketones through a carbon-carbon bond cleavage. In the reaction, two new carbon-carbon bonds were formed and one carbon-carbon bond was cleaved. It is very interesting that two different nucleophiles such as benzyl ketones and aromatics were coupled together without metal, which is unusual in organic synthesis.

  18. The carbon budget of the North Sea

    Directory of Open Access Journals (Sweden)

    A. Vieira Borges

    2004-08-01

    Full Text Available A carbon budget has been established for the North Sea, a shelf sea of the NW European continental shelf. The air-sea exchange of CO2 has been assessed as closing term of the budget. The carbon exchange fluxes with the North Atlantic Ocean dominate the gross carbon budget. The net carbon budget – more relevant to the issue of the contribution of the coastal ocean to the marine carbon cycle – is dominated by the carbon inputs from rivers, the Baltic Sea and the atmosphere. The dominant carbon sink is the final export to the North Atlantic Ocean. The North Sea acts as a sink for organic carbon. More than 90% of the CO2 taken up from the atmosphere is exported to the North Atlantic Ocean making the North Sea a highly efficient continental shelf pump for carbon.

  19. Carbon price volatility: Evidence from EU ETS

    International Nuclear Information System (INIS)

    This paper examines carbon price volatility using data from the European Union Emission Trading Scheme from a nonlinear dynamics point of view. First, we use a random walk model, including serial correlation and variance ratio tests, to determine whether carbon price history information is fully reflected in current carbon price. The empirical research results show that carbon price is not a random walk: the price history information is not fully reflected in current carbon price. Second, use R/S, modified R/S and ARFIMA to analyse the memory of carbon price history. For the period April 2005-December 2008, the modified Hurst index of the carbon price is 0.4859 and the d value of ARFIMA is -0.1191, indicating short-term memory of the carbon price. Third, we use chaos theory to analyse the influence of the carbon market internal mechanism on carbon price, i.e., the market's positive and negative feedback mechanism and the heterogeneous environment. Chaos theory proves that the correlation dimension of carbon price increases. The maximal Lyapunov exponent is positive and large. There is no obvious complex endogenous phenomenon of nonlinear dynamics the carbon price fluctuation. The carbon market is mildly chaotic, showing both market and fractal market characteristics. Price fluctuation is not only influenced by the internal market mechanism, but is also impacted by the heterogeneous environment. Finally, we provide suggestions for regulation and development of carbon market.

  20. Adsorption on the carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    DING Yi; YANG Xiao-bao; NI Jun

    2006-01-01

    Adsorption on single walled carbon nanotubes (SWCNTs) is a subject of growing experimental and theoretical interest.The possible adsorbed patterns of atoms and molecules on the single-walled carbon nanotubes vary with the diameters and chirality of the tubes due to the confinement.The curvature of the carbon nanotube surface enlarges the distance of the adsorbate atoms and thus enhances the stability of high coverage structures of adsorbate.There exist two novel high-coverage stable structures of potassium adsorbed on SWCNTs,which are not stable on graphite.The electronic properties of SWCNTs can be modified by adsorbate atoms and metal-semiconductor and semiconductor-semi-conductor transitions can be achieved by the doping of alkali atoms.