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Sample records for digestao quimica espectrometria

  1. Chemical vapor deposition (CVD) of uranium for alpha spectrometry; Deposicion quimica de vapor (CVD) de uranio para espectrometria alfa

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez V, M. L.; Rios M, C.; Ramirez O, J.; Davila R, J. I.; Mireles G, F., E-mail: luisalawliet@gmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2015-09-15

    The uranium determination through radiometric techniques as alpha spectrometry requires for its proper analysis, preparation methods of the source to analyze and procedures for the deposit of this on a surface or substrate. Given the characteristics of alpha particles (small penetration distance and great loss of energy during their journey or its interaction with the matter), is important to ensure that the prepared sources are thin, to avoid problems of self-absorption. The routine methods used for this are the cathodic electro deposition and the direct evaporation, among others. In this paper the use of technique of chemical vapor deposition (CVD) for the preparation of uranium sources is investigated; because by this, is possible to obtain thin films (much thinner than those resulting from electro deposition or evaporation) on a substrate and comprises reacting a precursor with a gas, which in turn serves as a carrier of the reaction products to achieve deposition. Preliminary results of the chemical vapor deposition of uranium are presented, synthesizing and using as precursor molecule the uranyl acetylacetonate, using oxygen as carrier gas for the deposition reaction on a glass substrate. The uranium films obtained were found suitable for alpha spectrometry. The variables taken into account were the precursor sublimation temperatures and deposition temperature, the reaction time and the type and flow of carrier gas. Of the investigated conditions, two depositions with encouraging results that can serve as reference for further work to improve the technique presented here were selected. Alpha spectra obtained for these depositions and the characterization of the representative samples by scanning electron microscopy and X-ray diffraction are also presented. (Author)

  2. Grace buys aquatic quimica to boost water treatment stake

    International Nuclear Information System (INIS)

    Hunter, D.

    1993-01-01

    How W.R. Grace (Boca Raton, FL) president and newly appointed CEO J.P. Bolduc plans to expand Grace's core businesses following his drastic portfolio pruning during the past 18 months is a key question for Grace watchers. Grace's acquisition of $70-million/year water treatment firm Aquatec Quimica (Sao Paulo) is one indicator. Grace's $300-million/year Dearborn water treatment business is currently a weak number three [in the world market], and we want to be number one or number two, nothing less, Bolduc insists. The Aquatc buy meets his criterion of a synergistic and strategic acquisition with which he plans to expand the business, backed by more focused R ampersand D. Disposal last month of Homco oil field services operation, for $98.5 million, takes Bolduc toward his $500-million target for the year for asset sales. These totaled $1.1 billion at the end of 1992. The final tally will be more than the $1.5-billion target previously stated, Bolduc says, due to higher realizations on certain sales and additions to the list, including Grace Culinary and Colowyo Coal

  3. Los manuales de quimica en Espana (1788--1845): Protagonistas, terminologia, clasificaciones y orden pedagogico

    Science.gov (United States)

    Munoz Bello, Maria Rosa

    La presente tesis doctoral es una investigacion sobre los manuales de quimica utilizados en Espana de 1788 a 1845. Este trabajo proporciona una perspectiva general de un tema relevante en las ultimas decadas en Historia de la Ciencia, el estudio de los libros de texto. De acuerdo con las ultimas investigaciones realizadas en este terreno, el acto pedagogico es considerado como un proceso creativo, como espacio de encuentro de actores e intereses muy diversos, matizando las ideas defendidas por Thomas S. Kuhn. Recordemos que segun Kuhn, los libros de texto ofrecen una vision consensuada y normalizada del estado de la ciencia de su epoca, por lo que sus autores eliminan deliberadamente toda controversia y presentan asi una imagen distorsionada de la actividad cientifica. En cambio, se ha mostrado, por ejemplo, que en la ensenanza participan no solamente profesores y alumnos sino tambien otros muchos actores y todos ellos no unicamente con intereses puramente pedagogicos sino tambien con diversos intereses politicos y economicos que pueden conocerse a traves del estudio de los manuales. En esta tesis se pretende analizar los manuales de quimica en Espana desde 1788 hasta 1845. Para poder llevar a cabo la investigacion ha sido necesario precisar el objeto de estudio (libro de texto de quimica) durante el periodo estudiado (1788-1845) ya que no es adecuado adoptar la imagen actual de una disciplina que sufrio sustanciales cambios durante la epoca estudiada. Esta investigacion se centra en un momento especialmente importante para la quimica y que algunos historiadores han llegado a considerar "revolucionario". Durante estos anos se produjo un cambio importante en las teorias quimicas sobre la combustion y el concepto de elemento, asi como una reforma terminologica que originaron la aparicion de importantes controversias. Ademas, debido a la relacion de la quimica con otras disciplinas como la historia natural o la fisica ha sido necesario restringir el objeto de estudio

  4. Risk analysis in the chemical industry; Analisis de riesgos en la industria quimica

    Energy Technology Data Exchange (ETDEWEB)

    Rea Soto, Rogelio; Sandoval Valenzuela, Salvador [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2000-07-01

    The Instituto de Investigaciones Electricas has a group of risk analysis (GAR), specialized in the most advanced methodologies to apply them in diverse industries of the productive sector, such as the nuclear, the oil and the chemical industries. In this work the integrated methodology that the GAR uses to make risk analysis in the chemical and oil industries is described. These analyses have as an objective to make a meticulous evaluation of the system design, the operation practices, the maintenance and inspection policies and the emergency plans. [Spanish] El Instituto de Investigaciones Electricas cuenta con un grupo de analisis de riesgo (GAR), especializado en las metodologias mas avanzadas para aplicarlas en diversas industrias del sector productivo, como lo son la nuclear, la petrolera y la quimica. En este trabajo se describe la metodologia integrada que el GAR utiliza para realizar analisis de riesgos en las industrias quimica y petrolera. Estos analisis tienen como objetivo realizar una minuciosa evaluacion del diseno del sistema, las practicas de operacion, las politicas de mantenimiento e inspeccion y los planes de emergencia.

  5. Development and application of safety and waste management protocols for the Laboratorio de Ingenieria Quimica

    International Nuclear Information System (INIS)

    Scott Jimenez, Stephanie

    2014-01-01

    Security and waste management protocols are developed for the laboratory de la Escuela de Ingenieria Quimica at the Universidad de Costa Rica. The protocols are elaborated according to the provisions and guidelines stipulated in the Costa Rican legislation, technical references and documents issued by the chemical regency of the Universidad de Costa Rica. An inspection guide was prepared and applied as diagnostic tool for the evaluation of the safety conditions and handling of chemical substances in the laboratory. Inspections of the physical plant and interviews to area managers were realized. The results obtained have allowed to implement improvements of the activities in safe working environment conditions and teaching; and an adequate signaling and demarcation of the facilities, location and recharge of fire extinguishers. An emergency plan is elaborated for the Laboratorio de Ingenieria Quimica, by performing a sequence of stages proposed by Comision Nacional de Emergencias. In addition, a plan for the safe and effective management of waste generated is made based on the reagents most frequently used in the different practices. The method of storage Flinn Scientific was selected as the most appropriate method to organize and distribute chemicals in the laboratory reagent storage area, obtaining the highest percentage in the decision matrix. Security aspects in the registration and documentation system implemented in the laboratory administration are evaluated by a checklist. This assessment has allowed to propose improvements, to increase the efficiency and to obtain an easy storage, control and a fast search of the information by means of the procedures documented and elaborated. Some of the recommendations proposed have been the establishment of an emergency action committee, the reduction of unnecessary quantities of chemicals stored, training on safety, operation of fire extinguisher and first aid; and construction of an emergency exit, etc. [es

  6. Laboratório virtual de física moderna: sistema para espectrometria gama

    Directory of Open Access Journals (Sweden)

    Nelson Canzian da Silva

    2015-03-01

    Full Text Available http://dx.doi.org/10.5007/2175-7941.2015v32n2p542 O artigo descreve como foi implementada uma simulação computacional de um sistema de detecção de radiação ionizante semelhante ao encontrado em tradicionais laboratórios de física moderna. A simulação modela um sistema composto por “fontes” radioativas emissoras de fótons com energias bem definidas e de um “detector” de comportamento semelhante a um sistema de espectrometria de fótons (cintilador + fotomultiplicadora + analisador multicanal. Como em um sistema real, além de escolher a fonte, é possível ajustar a tensão na fotomultiplicadora, o ganho do amplificador e o ganho de conversão do analisador multicanal, observando-se o efeito disso nos “dados” adquiridos. São apresentados e discutidos resultados obtidos com o simulador para alguns roteiros de experimentos (calibração em energia, identificação de energias desconhecidas, determinação da resolução em energia etc.. A simulação foi utilizada com duas turmas do curso de licenciatura em física a distância da UFSC em 2011 e em 2014, associadas à realização do experimento real. Permeando o texto são discutidas as motivações e os problemas do uso das simulações neste contexto. À guisa de conclusão é discutido como o trabalho se relaciona às principais metas dos laboratórios introdutórios de física, segundo um comitê da American Physical Society especificamente constituído para isso.

  7. Chemical modeling of formation water of the active Luna, Tabasco; Modelacion quimica de aguas de formacion del activo Luna, Tabasco

    Energy Technology Data Exchange (ETDEWEB)

    Barragan R, Rosa M; Portugal M, Enrique; Arellano G, Victor M. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Martinez A, Ana E; Ascencio C, Fernando [Petroleos Mexicanos (Mexico)

    2001-07-01

    From the data of chemical composition of the water, the chemical equilibrium at a given temperature can be modeled for, later, obtain the saturation indexes of characteristic minerals with the intention of knowing or predict which phases can form the deposits. The Gerencia de Productividad de Pozos (GPP) of the Subdivision of Technology and Professional Development (STDP) of PEMEX, has among its objectives to promote studies tending to solve problematic that affect the wells productivity, reason why it showed interest in making a study of chemical modeling of formation waters of the Active Luna, in order to know the saturation state of the main mineral phases. This way a joint project was executed in 1997 among the GPP, the Active of Production Luna of PEMEX and the Gerencia de Geotermia of the IIE. The objectives of the project were: (a) sampling and physicochemical characterization of waters pertaining to oil wells of the Actives of Production Luna, and (b) modeling of the chemical equilibrium at well head and deposit conditions to obtain saturation indexes of characteristic minerals of hydrothermal systems, in order to predict the mineral phases that can be found in superficial and deep incrustations. [Spanish] A partir de los datos de composicion quimica del agua, pude modelarse el equilibrio quimico a una temperatura dada para, posteriormente, obtener los indices de saturacion de los minerales caracteristicos con el objeto de conocer o predecir cuales fases pueden formar los depositos. La Gerencia de Productividad de Pozos (GPP) de la Subdireccion de Tecnologia y Desarrollo Profesional (STDP) de Pemex, tiene entre sus objetivos promover estudios tendientes a resolver problematicas que impactan la productividad de los pozos, por lo que mostro interes en realizar un estudio de modelacion quimica de las aguas de formacion del Activo Luna, con el proposito de conocer el estado de saturacion de las principales fases minerales. De esta forma se realizo un proyecto

  8. Comprension de los conceptos de los enlaces ionico y covalente en estudiantes universitarios del primer curso de quimica general

    Science.gov (United States)

    Ballesteros Benavides, Maria Elvira

    Para este trabajo utilizamos el estudio de casos cualitativo que se llevo a cabo en una universidad privada de Puerto Rico. Empleamos como unidad de analisis el concepto de enlace quimico, ionico y covalente. Los participantes fueron los estudiantes de la seccion nocturna del curso de Quimica General I. La investigacion se desarrollo por medio de dos entrevistas de persona a persona, observaciones de las expresiones no verbales y la hoja de identificacion de conceptos. Para la triangulacion tomamos en consideracion las preconcepciones erroneas, las concepciones alternativas y el mapa de conceptos de cada participante. Preparamos un mapa de conceptos para el enlace quimico validado por un comite de expertos. Tambien, elaboramos los mapas de conceptos de los participantes que sirvieron para varios propositos: conocer la estructura conceptual, expresar los logros, hacer comparaciones e identificar la presencia de concepciones alternativas. Entre los hallazgos encontramos que todos los participantes poseen conocimiento previo de los enlaces quimicos ionico y covalente y dentro de ese conocimiento existen preconcepciones erroneas mas numerosas para el enlace ionico. Al principio del semestre el 50% de los participantes demostraron tener "carencia fuerte de conceptos" tanto para el enlace ionico como para el covalente. Al finalizar el semestre encontramos en el 40% de los participantes concepciones alternativas tanto para el enlace ionico como para el covalente y el 90% no lograron distinguir un enlace del otro. Nuestras conclusiones fueron que los participantes sin distincion del aprovechamiento academico demostraron tener la tendencia de "carencia fuerte de conceptos" tanto para el enlace ionico como para el covalente, presentaron dificultad al integrar los conceptos de los enlaces quimicos ionico y covalente que se pusieron de manifiesto al dar los ejemplos. Las preconcepciones erroneas contribuyen en el desarrollo de las concepciones alternativas. Ademas, los

  9. Bases para la elaboracion de unidades didacticas de calidad en el area de ciencias (Fisica y Quimica 3 deg ESO)

    Science.gov (United States)

    Maccioni, Elena Lucia

    Este Trabajo Fin de Master tiene como objeto, el estudio previo de la educacion de la ciencia en la actualidad y mas destacable, del diseno de las unidades didacticas segun las metodologias mas frecuentes aplicadas por los diferentes sistemas educativos en el area de las Ciencias teniendo en cuenta la importancia y el efecto de la psicologia del alumnado y todo ello como no puede ser de otro modo bajo el corse de la Legislacion aplicable, Estatal, Autonomica y europea. Con estos antecedentes, se extrae cuales son las preguntas que deben contestarse en la elaboracion de una unidad didactica de calidad en el contexto, generacional (edad y sexo), del Proyecto Educativo de Centro, y de la Programacion del Departamento, discutiendo y justificando cada uno de los apartados en que estructuradamente dividiremos dicha Unidad, con un formato manejable, util, y dinamico en el tiempo que sea un verdadero instrumento educativo de aula. Teniendo en cuenta estas premisas, se procede a hacer una recopilacion de una misma unidad didactica publicada por diferentes editoriales, elegidas no al azar, sino en funcion de su penetracion editorial en nuestros centros de ESO, siendo las elegidas (SM y Oxford). Las diferentes unidades seleccionadas son analizadas de forma critica, atendiendo a los criterios generales de calidad bajo parametros cientificos y normativos, concluyendo con la aportacion final que es la redaccion de unas pautas cientifico-pedagogicas, para redactar unidades didacticas de calidad en el area de la Ciencias, en concreto en la Asignatura de Fisica y Quimica de 3º de ESO.

  10. Implementação da Técnica de Dessorção Térmica Programada (TPD) usando Espectrometria de Massa Quadrupolo

    OpenAIRE

    Barreto, Ana Marta Fortunato

    2011-01-01

    Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do Grau de Mestre em Engenharia Física O projecto “Implementação da Técnica de Dessorção Térmica Programada (TPD) usando Espectrometria de Massa Quadrupolo”, apresentado nesta Dissertação de Mestrado em Engenharia Física, surgiu como uma proposta de requalificação ao aparelho de análise de superfícies Multitécnica. A dessorção térmica é o fenómeno que permite a separação física de ...

  11. Espectrometria de massas avançada em estudos estruturais de metabólitos de fármacos e proteínas

    OpenAIRE

    Alexandre Ferreira Gomes

    2014-01-01

    Resumo: Este trabalho foi dividido em dois capítulos, tendo como temática geral a aplicação de técnicas modernas baseadas em espectrometria de massas (MS) no estudo da biotransformação de fármacos (capítulo I) e em proteômica estrutural por ligação cruzada e mobilidade iônica (capítulo II). No capítulo I, foram estudadas rotas de fragmentação por dissociação induzida por colisão (CID), perfis de metabólitos in vivo em ratos e farmacocinética de derivados de 4-anilinoquinazolina, candidatos a ...

  12. Marcadores séricos e espectrometria de massa no diagnóstico do câncer Serum markers and mass spectrometry in the diagnosis of cancer

    Directory of Open Access Journals (Sweden)

    Paulo Costa Carvalho

    2006-12-01

    Full Text Available Esta revisão abrange as principais técnicas, limitações e utilidades da espectrometria de massa aplicada à análise de fluidos biológicos para buscar biomarcadores com potencialidade de diagnóstico médico. Atualmente esse método é capaz de discernir, em segundos, padrões moleculares diferencialmente expressos entre indivíduos controles e com câncer. Resultados da literatura apontam a espectrometria de massa como metodologia promissora no futuro do diagnóstico.This manuscript reviews mass spectrometry methods and limitations for analisys of biological fluids in the search for biomarkers that can aid medical diagnosis. Currently, mass spectrometry has the ability to discriminate differentially expressed molecular patterns among cancer patients and control subjects. Results in the literature point mass spectrometry as having a major role in the future of medical diagnosis.

  13. Utilização da espectrometria de massas no estudo de produtos de transformação/degradação de fármacos de uso humano e veterinário

    OpenAIRE

    Jéferson Segalin

    2015-01-01

    A espectrometria de massas, acoplada ou não a outras técnicas, tem sido de grande utilidade na determinação de novos compostos, produtos de transformação/degradação, metabólitos e na quantificação em nível de traços nas mais diferentes matrizes, devido à grande versatilidade dessa técnica, especialmente em relação aos modos de análise. Neste trabalho foi sistematizada uma metodologia para a aplicação das técnicas de espectrometria de massas na identificação de produtos de transformação/degrad...

  14. Microbiology of anaerobic digestion; Microbiologia da digestao anaerobica

    Energy Technology Data Exchange (ETDEWEB)

    Novaes, Rosana Filomena Vazoller [CETESB, Sao Paulo, SP (Brazil)

    1988-12-31

    Considerations was made about the microorganisms involved in the anaerobic digestion of wastes. Are also presented, the main results on this subject obtained, until now, in the studies carried on the group of anaerobic microbiology researchers from the Sanitary Company of Sao Paulo State, Brazil. (author) 23 refs., 8 figs., 3 tabs.

  15. Determinação de compostos nitrogenados aromáticos em alcatrão de carvão através da cromatografia gasosa bidimensional abrangente acoplada à espectrometria de massas

    OpenAIRE

    Juliana Macedo da Silva

    2014-01-01

    A cromatografia gasosa bidimensional abrangente (GC×GC) é uma excelente técnica analítica para a determinação de diversos compostos em matrizes complexas, como é o caso do alcatrão de carvão, objeto deste estudo. O alcatrão foi obtido através do processo de pirólise e submetido à análise por GC×GC visando a especiação de compostos nitrogenados aromáticos. A GC×GC acoplada à espectrometria de massas com analisadores do tipo quadrupolar (qMS) e por tempo de voo (TOFMS) foram utilizados para a d...

  16. Development of a technical scheme for the management of chemical dangerous substances in hospitable environments; Desarrollo de un esquema tecnico para la gestion de sustancias quimicas peligrosas en ambientes hospitalarios

    Energy Technology Data Exchange (ETDEWEB)

    Calleja Amador, C E

    2002-07-01

    The chemical substances that are used in the hospitals, and their remainders, represent risks for the environment, the health and security of those who work in these establishments, and of the civil population. The deficiency of a norm that establishes the directives for the handling responsible for such products in the hospitals that our country has motivated the elaboration of a technical scheme that serves as it guides for the correct manipulation, storage and safe disposition of chemical substances in the twenty-nine hospitals of the Caja Costarricense del Seguro Social, establishing Procedures of Standard Operation for its management. To development of the guideline proposal it took a sample of hospitals that includes three levels of comple complexity: national, regional and peripheral. Applying a methodology of evaluation of risks two factors of risk of hospitable were determined, the zones and the population but affected by the existence of chemical substances, which allowed to identify some operative deficiencies in the product handling diverse. The qualitative analysis of the results lead to the elaboration of a technical scheme that includes an instrument for the identification of risks, guideline for the management responsible for hospitable chemical substances, a friendly tool computations like complementary source of intelligence and the proposal of a governing group in charge of the monitoring of the fulfillment of these lineament. (Author) [Spanish] Las sustancias quimicas que se usan en los hospitales, y sus residuos, representan riesgos para el medio ambiente, para la salud y seguridad de quienes trabajan en estos establecimientos, y de la poblacion civil. La carencia de una normativa que establezca las directrices para el manejo responsable de tales productos en los hospitales de nuestro pais ha motivado la elaboracion de un esquema tecnico que sirva como guia para la correcta manipulacion, almacenamiento y disposicion segura de sustancias

  17. Uso da técnica de espectrometria de massas com ionização por eletrospray (ESI-MS) para o estudo do mecanismo de reações orgânicas e avaliação do perfil de fragmentação de bis-hidroxiiminas aromáticas

    OpenAIRE

    Maria Elisa Romanelli Diniz

    2011-01-01

    A Espectrometria de Massas com Ionização por Eletrospray (ESI-MS) foi utilizada na investigação dos mecanismos de duas reações orgânicas: Reação de Zincke e Reação de Aza Diels Alder. Um estudo sistemático sobre a fragmentação das formas protonadas de alguns ligantes do tipo Salofen (bis-hidroxiiminas aromáticas) foi conduzido também neste trabalho. No monitoramento da reação de Zincke foram observados, além dos produtos tradicionais, intermediários inéditos, cujas estruturas foram propostas ...

  18. Isotope determination of sulfur by mass spectrometry in soil samples Determinação isotópica de enxofre por espectrometria de massas (irms em amostras de solo

    Directory of Open Access Journals (Sweden)

    Alexssandra Luiza Rodrigues Molina Rossete

    2012-12-01

    Full Text Available Sulphur plays an essential role in plants and is one of the main nutrients in several metabolic processes. It has four stable isotopes (32S, 33S, 34S, and 36S with a natural abundance of 95.00, 0.76, 4.22, and 0.014 in atom %, respectively. A method for isotopic determination of S by isotope-ratio mass spectrometry (IRMS in soil samples is proposed. The procedure involves the oxidation of organic S to sulphate (S-SO4(2-, which was determined by dry combustion with alkaline oxidizing agents. The total S-SO4(2- concentration was determined by turbidimetry and the results showed that the conversion process was adequate. To produce gaseous SO2 gas, BaSO4 was thermally decomposed in a vacuum system at 900 ºC in the presence of NaPO3. The isotope determination of S (atom % 34S atoms was carried out by isotope ratio mass spectrometry (IRMS. In this work, the labeled material (K2(34SO4 was used to validate the method of isotopic determination of S; the results were precise and accurate, showing the viability of the proposed method.O enxofre tem papel essencial em plantas, sendo um dos principais nutrientes em diversos processos metabólicos; ele apresenta quatro isótopos estáveis (32S, 33S, 34S e 36S, com abundância natural de 95,00, 0,76, 4,22 e 0,014 % em átomos, respectivamente. Desenvolver um método para determinação isotópica do S por espectrometria de massas de razão isotópica (IRMS em amostras de solo foi o objetivo deste trabalho. A oxidação de S orgânico a sulfato (S-SO4(2- foi avaliada utilizando a oxidação via seca com agentes oxidantes alcalinos. A concentração S-SO4(2- foi determinada pelo método turbidimétrico, e os resultados mostraram que o processo de conversão foi adequado. A obtenção do gás SO2 foi por decomposição térmica do BaSO4 em uma linha de vácuo a 900 ºC, em presença de NaPO3. A determinação isotópica do S (% em átomos de 34S foi realizada em um espectrômetro de massa (IRMS. Neste trabalho, a

  19. Estudio de la estructura logica utilizada en la ensenanza y el aprendizaje de los conceptos sobre el comportamiento de gases en el curso introductorio de quimica a nivel universitario

    Science.gov (United States)

    Costa Diaz, Agnes

    El estudio que se presenta es de caracter cualitativo, un estudio multicasos donde se estudia la estructura logica utilizada por cuatro (4) profesores universitarios que ensenan el curso introductorio de quimica, en la planificacion, presentacion y evaluacion del tema sobre el comportamiento de los gases. Se utilizaron varias fuentes de informacion como: cuestionarios de profesores y estudiantes, entrevistas, grabaciones videomagnetofonicas, materiales didacticos y una prueba conceptual, entre otros. La informacion recopilada fue analizada de acuerdo al orden logico del contenido presentado, el estilo de ensenanza del profesor, las tecnicas y estrategias utilizadas para el desarrollo de destrezas de pensamiento, el ambiente fisico en el salon de clase y los instrumentos de evaluacion y avaluo. El estudio demuestra que lo que los profesores piensan y planifican para hacer sus presentaciones no necesariamente es lo que ocurre en el salon de clases. El desarrollo de destrezas de pensamiento, que constituye una prioridad de los profesores, no se elaboran efectivamente. El uso de las estrategias de resolucion de problemas numericos predomino. La participacion del estudiante en el salon de clases fue limitada y no se logro demostrar el desarrollo de las destrezas de pensamiento deseadas. Aunque los profesores tienen su propio estilo de ensenanza, el orden logico del contenido presentado en clase fue el mismo o siguio muy de cerca el orden establecido por el libro de texto. Los profesores utilizaron preferentemente la tiza y la pizarra para sus presentaciones y la dinamica en el salon de clases fue esencialmente tradicional. Los profesores hicieron su presentacion y los estudiantes copiaron pasivamente la informacion. Las evaluaciones de los estudiantes fueron esencialmente, pruebas escritas de seleccion multiple de acuerdo con el estilo en que se les enseno. El avaluo fue casi inexistente. La prueba conceptual administrada revela un aprendizaje pobre en los conceptos mas

  20. Estudio de arcillas peruanas por espectrometria mossbauer

    OpenAIRE

    Salazar Rodriguez, Roberto; Salazar Rodriguez, Roberto

    1982-01-01

    El hecho de que las arcillas hayan sido y sean en la actualidad el material más fácil, útil, abundante y barato de obtener, explica la abundante bibliografía sobre este tema. La profusión de estas, sobre la superficie terres¬tre, permite obtenerla sin ninguna dificultad en cualquier lugar sobre la tierra. Desde tiempos remotos el hombre ha confeccionado utensilios a base de arci¬llas y probablemente desde que aprende a usar el fuego. Con la ayuda de es te construye primero utensilios rudim...

  1. Multidimensional Gamma-Ray Spectrometry and its Use in Biology; La Spectrometry Gamma Multidimensionnelle et son Application en Biologie; Mnogomernaya spektrometriya gamma-luchej i ee ispol'zovanie v biologii; La Espectrometria Gamma Multidimensional y su Empleo en Biologia

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, J. M.; Kornberg, H. A. [Battelle Memorial Institute, Pacific Northwest Laboratory, Richland, WA (United States)

    1965-10-15

    cause du rayonnement gamma de 1,47 MeV de cet element. La plupart des radionuclides se desintegrant en emettant deux ou plusieurs rayons gamma en cascade, la nouvelle methode permet de faire une mesure selective directe et se prete a maintes applications. C'est ainsi que {sup 22}Na (radionuclide normalement produit par les rayons cosmiques), {sup 134}Cs et {sup 137}Cs (produits de fission) peuvent etre facilement mesures a la concentration naturelle (dans certains cas dans des proportions inferieures a 1 dpmAg) dans la viande, le poisson et autres denrees alimentaires ainsi que dans l'urine, ce qui permet de faire des etudes sur les quantites fixees et excretees. Cette methode pourrait etre utilisee dans les etudes comportant l'emploi de traceurs et elle serait particulierement precieuse pour la mesure simultanee de l'absorption, de la fixation et de l'assimilation dans l'organisme animal de plusieurs composes marques de maniere appropriee. En utilisant cette methode avec l'analyse par activation neutronique on peut mesurer dans les tissus et dans le sang un groupe importantd'elements d'une concentration de quelques milliardiemes. (author) [Spanish] La espectrometria gamma multidimensional es una nueva tecnica de medicion de radionueclidos especialmente aplicable en biologia. Esta tecnica instrumental permite identificar y medir directamente los distintos emisores gamma de mezclas complejas de radionueclidos en diversas matrices, sin necesidad de un tiatamiento qufmico previo. El sistema detector esta ideado con miras a obtener una gran sensibilidad, utilizando dos grandes detectores de NaI(Tl) (6 pulg de diametro y 4 pulg de espesor), una elevada selectividad, gracias al empleo de tecnicas de recuento de coincidencias que separan ios espectros gamma aprovechando las caracterfsticas de desintegracitfn gamma de cada radionuclido, y una actividad de fondo sumamente baja, asi como una interferencia debida al efecto Compton muy atenuada. Esas propiedades se consiguen

  2. Evaluation of noni (Morinda citrifolia volatile profile by dynamic headspace and gas chromatography-mass spectrometry Avaliação do perfil de voláteis em noni (Morinda citrifolia por headspace dinâmico e cromatografia gasosa-espectrometria de massas

    Directory of Open Access Journals (Sweden)

    Adriana Sousa

    2010-09-01

    Full Text Available Noni is a fruit that has interested the scientific community due to its medicinal and functional activities. Different products that contain noni are already in the market, but their consumption could be impaired by their distinctive unpleasant aroma and flavor. The aim of this work was to evaluate the noni pulp volatile profile by dynamic headspace and gas chromatography-mass spectrometry. Thirty seven volatile compounds were detected, mainly alcohols (63.3%, esters (26.9%, cetones (7.4%, and acids (1.2%.O noni é um fruto que tem interessado à comunidade científica por sua atividade funcional e medicinal. Já se encontram no mercado diferentes produtos que contêm noni em sua composição, mas seu consumo tem sido prejudicado por seu aroma e sabor desagradáveis. O objetivo deste trabalho foi o de avaliar o perfil de voláteis da polpa de noni pela técnica de headspace dinâmico e cromatografia gasosa-espectrometria de massas. Foram detectados 37 compostos voláteis, sendo os principais: alcoóis (63,3%, ésteres (26,9%, cetonas (7,4% e ácidos (1,2%.

  3. Role of Exchange Equilibria in Structural Chemistry; Role des Equilibres d'Echange en Chimie Structurale; Rol' ravnovesiya obmena v strukturnoj khimii; Papel de los Equilibrios de Intercambio en Quimica Estructural

    Energy Technology Data Exchange (ETDEWEB)

    Van Wazer, J. R.; Moedritzer, K. [Monsanto Company, St. Louis, MI (United States)

    1965-10-15

    partes de estructuras moleculares. Ademas, se han estudiado cuantitativamente los equilibrios entre estructuras ciclicas y aciclicas. El hincapie que la quimica estructural hace sobre los compuestos del carbono (como lo pone de manifiesto la division de la'quimica descriptiva en las categorias e inorganica) se atribuye al hecho de ser sumamente lentas las reacciones de intercambio donde intervienen enlaces C-C o uniones entre carbono y cualquier otro atomo que no posea orbitales de enlace libres en niveles bajos (por ejemplo: Si, Ge, N, P, As, O, S, Se, F, Cl, Br). No obstante ello, hay vastos dominios de la quimica inorganica que no han podido describirse dado que las moleculas sufren reacciones de intercambio tan rapidas que resulta imposible separarlas. Sin embargo, se las puede identificar y valorar por metodos ffsicos (tales como la resonancia magnetica nuclear) con constantes de tiempo pequenas, a condicion de someter los datos obtenidos a un tratamiento matematico adecuado, siendo este tratamiento de una complejidad que justifica el empleo de una calculadora rapida [6,16]. Los topicos expuestos se ejemplifican [2, 12, 24, 28] mediante sistemas especificos seleccionados entre. los trabajos mas recientes del autor. Ademas de los estudios de equilibrio, se presta atencion a la cinetica [26, 27] de los procesos de intercambio. Se presentan varios teoremas generales que permiten predecir los tipos y cantidades de productos [6, 18]. (author) [Russian] Hotja v proshlom znachitel'- naja dolja usilij v oblasti reakcij obmena byla posvjashhena razboru monofunkcional'nyh zame- stitelej v polifunkcional'nom atome ili ego chasti, slozhnye molekuly mogut takzhe pod- vergat'sja obmenu chastej i davat' takim obrazom ravnovesnoe raspredelenie razlichnyh molekuljarnyh razmerov i form. Ispol'zovanie jadernogo magnitnogo rezonansa (JaMR) s vysokim razresheniem dlja issledovanija takih ravnovesnyh smesej slozhnyh soedinenij bylo opisano v 1964 i 1965 g g . vo mnogih dokladah

  4. Chemical and isotopic characteristics of rainwater at Los Humeros geothermal field, Puebla, Mexico and surrounding areas; Caracteristicas quimicas e isotopicas del agua de lluvia en el campo geotermico de Los Humeros, Puebla, Mexico y zonas aledanas

    Energy Technology Data Exchange (ETDEWEB)

    Tovar Aguado, Rigoberto; Cruz Grajales, Irma [Comision Federal de Electricidad, Los Humeros, Puebla (Mexico)

    2000-12-01

    A study of chemical and isotopic characteristics of rainwater at Los Humeros geothermal field was undertaken for the second consecutive year. Samples were collected in seven stations-two inside the field and five on the periphery. In 1996, a total of 99 samples were collected and 104 were collected in 1997. Of these, 19-18.26% of the total-had a negative alkalinity. The Atempan (No.5) and Campamento (No.1) stations showed the highest number of anomalous samples (31.25 and 27.8%, respectively). Anomalous samples in Perote station were not observed a result that we attribute to the predominant wind direction. The results for the Campamento station are attributed to the thermal inversion phenomena occurring when the samples with negative alkalinity were obtained. Concentrations of cations in some samples were relatively high, with the maximum concentration of calcium in the Los Humeros station (79.7 ppm) . Other significantly high values were found in the Texcal station (34.8 ppm) and Perote (33.8 ppm) due to the presence of dust particles scattered in the air and because of the lack of pavement where the sampling stations are located. Another factor affecting these figures could be the presence of block and lime factories in the neighborhood. Although measured concentrations may seem high, reports exist with similar concentrations in nongeothermal areas. Oxygen-18 and deuterium contents were determined for each stations, mixing anomalous samples. The results show that the most enriched samples correspond to the San Juan Xiutetelco, Puebla (No. 6) station and the minimum to the Perote Veracruz (No. 7) station. The concentration of SO{sub 4} has marine and industrial origins, with a contribution of the first source ranging between 10 and 25 percent. [Spanish] En el campo geotermico de Los Humeros, Puebla se realizo, por segundo ano consecutivo, la caracterizacion quimica e isotopica de agua de lluvia en muestras colectadas en siete estaciones, dos localizadas dentro

  5. Identificação de compostos orgânicos e farmacêuticos em esgoto hospitalar utilizando cromatografia gasosa acoplada a espectrometria de massa Identification of organic and pharmaceutical compositions in hospital wastewater using a gas chromatograph coupled to mass spectrometry

    Directory of Open Access Journals (Sweden)

    Francisco Vieira Paiva

    2011-03-01

    Full Text Available Os resíduos líquidos provenientes dos estabelecimentos assistenciais de saúde são mais complexos do que os esgotos domésticos. Sua composição contém inúmeros compostos farmacêuticos, saneantes, elementos radiativos e de laboratórios. O conhecimento desses compostos pode auxiliar na escolha do tratamento adequado para esses esgotos e diminuir os impactos ambientais nos corpos receptores. A pesquisa foi realizada utilizando um sistema combinado (UASB e lodos ativados para tratar a água residuária de um hospital. Neste trabalho, foram realizadas análises físico-químicas para caracterização do esgoto e cromatografia gasosa acoplada à espectrometria de massa para identificação de compostos químicos farmacêuticos, podendo-se constatar a presença de inúmeros elementos residuais dos fármacos usados no hospital.Liquid waste residues from health care establishments are more complex than those from residential sewage. Their composition contains several pharmaceutical chemical composites, sanitizers, radioactive, and laboratorial elements. Knowing about these composites may aid in choosing the proper treatment for these sewages, and diminish the environmental impact in receptors. The study was carried out in a combined system (UASB and activated sludge to treat a hospital wastewater. In this experiment, material and chemical analyses were employed to trace sewage characteristics and gas chromatography associated with mass spectrometry to identify pharmacologic chemical composites, where innumerous residual elements were found in chromatographs.

  6. Chemical Production using Fission Fragments; Emploi des fragments de fission dans la production de substances chimiques; Ispol'zovanie produkto v raspada v khimicheskom proizvodstve; Empleo de los fragmentos de fision en la industria quimica

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, J K; Moseley, F [AERE, Harwell (United Kingdom)

    1960-07-15

    'eau. Aucun des systemes etudies jusqu'a present ne parait offrir de possibilites interessantes pour la grande industrie chimique. (author) [Spanish] En una memoria presentada en la segunda Conferencia Internacional sobre la Utilizacion de la Energia Atomica con Fines Pacificos [A/Conf. 15/P. 76] se expusieron algunas consideraciones , atendiendo al diseno de los reactores, sobre la utilizacion de la energia de retroceso de los fragmentos de fision para la produccion de ciertos compuestos quimicos de importancia industrial. La presente memoria pasa revista a los progresos realizados desde entonces en esta materia por el Atomic Energy Research Establishment de Harwell. Los autores examinan la relacion entre el alcance y la energia para los fragmentos de fision al discutirse la eleccion del combustible para un reactor destinado a la produccion de compuestos quimicos y describen la variacion de efecto quimico observada a lo largo de la trayectoria de los fragmentos de fision en la irradiacion de mezclas de nitrogeno y oxigeno. Analizan tambien los resultados de investigaciones recientes acerca de los efectos de fragmentos de fision sobre mezclas de monoxido de carbono e hidrogeno y sobre el vapor de agua. Al parecer, ninguno de los sistemas estudiados hasta la fecha ofrece perspectivas particularmente interesantes para la industria quimica pesada. (author) [Russian] V doklade, predstavlennom ran'she na Vtoroj mezhdunarodnoj konferentsii Organizatsii Ob'edinennykh Natsij po mirnomu ispol'zovaniyu atomnoj ehnergii (A/Conf. 15/P. 76) v svyazi s konstruktsiej reaktorov obsuzhdalis' nekotorye soobrazheniya otnositel'no vozmozhnosti ispol'zovaniya ehnergii otdachi produktov raspada dlya proizvodstva vazhnykh dlya promyshlennosti khimikaliev. V nastoyashchem doklade rezyumiruyutsya bolee nedavnie rezul'taty, dostignutye v ehtoj oblasti Nauchno-issledo-vatel'skim institutom po atomnoj ehnergii v KHaruehlle. Sootnoshenie mezhdu prokhodimym rasstoyaniem i ehnergiej produktov deleniya

  7. Development and validation of a method for detection and quantification of ochratoxin A in green coffee using liquid chromatography coupled to mass spectrometry Desenvolvimento e validação de metodologia na detecção e na quantificação de Ocratoxina A no café verde utilizando cromatografia líquida acoplada à espectrometria de massas

    Directory of Open Access Journals (Sweden)

    Raquel Duarte da Costa Cunha Bandeira

    2012-12-01

    Full Text Available A method using Liquid Chromatography Tanden Mass Spectrometry (LC-MS/MS with matrix-matched calibration curve was developed and validated for determining ochratoxin A (OTA in green coffee. Linearity was found between 3.0 and 23.0 ng.g-1. Mean recoveries ranged between 90.45% and 108.81%; the relative standard deviation under repeatability and intermediate precision conditions ranged from 5.39% to 9.94% and from 2.20% to 14.34%, respectively. The limits of detection and quantification were 1.2 ng.g-1 and 3.0 ng.g-¹, respectively. The method developed was suitable and contributed to the field of mycotoxin analysis, and it will be used for future production of the Certified Reference Material (CRM for OTA in coffee.Um método utilizando Cromatografia Líquida de Alta Eficiência-Espectrometria de Massas Sequencial (CLAE-EM/EM com curva de calibração em matriz foi desenvolvido e validado para a determinação de ocratoxina A (OTA em café verde. A linearidade foi demonstrada entre 3,0 e 23,0 ng.g-1. As recuperações médias variaram entre 90,45% e 108,81%; o desvio padrão relativo sob condições de repetitividade e precisão intermediária foram de 5,39% e 9,94% e de 2,20% e 14,34%, respectivamente. Os limites de detecção e quantificação foram 1,2 ng.g-1 e 3,0 ng.g-, respectivamente. O método desenvolvido foi adequado, contribuiu para o campo de análises em micotoxinas e será usado para a futura produção de Material de Referência Certificado (MRC para OTA em café.

  8. (E-2-Nonenal determination in brazilian beers using headspace solid-phase microextraction and gas chromatographic coupled mass spectrometry (HS-SPME-GC-MS Determinação de (E-2-nonenal em cervejas brasileiras utilizando microextração em fase sólida do headspace e cromatografia gasosa acoplada a espectrometria de massas

    Directory of Open Access Journals (Sweden)

    Rodrigo Scherer

    2010-05-01

    Full Text Available (E-2-nonenal is considered an important off-flavor of beer, related to the flavor of beer staling. In this study, a new method for determination of (E-2-nonenal in beer using headspace solid-phase microextraction and gas chromatographic coupled mass spectrometry (HS-SPME-GC-MS was developed and applied in Brazilian beer samples. The extractions were carried out in CAR-PDMS (carboxen-polydimethylsiloxane fiber and the best results were found with 15 minutes of equilibrium and 90 minutes of extraction at 50 °C. The method was linear in the range from 0.02 to 4.0 μg.L-1 with correlation coefficient of 0.9994. The limits of detection and quantification were 0.01 and 0.02 μg.L-1, respectively. 96.5% of recovery and 4% precision (RSD were obtained in the fortification of beer samples with 2.0 μg.L-1 of (E-2-nonenal. The developed method proved to be simple, efficient and highly sensitive to the determination of this analyte being easily applied in the quality control of the brewery. (E-2-nonenal was found in all beer samples analyzed with levels between 0.17 and 0.42 μg.L-1.O (E-2-nonenal é considerado um importante off-flavor da cerveja, sendo relacionado ao sabor de cerveja envelhecida. Neste estudo, um novo método para determinação de (E-2-nonenal em cerveja usando microextração em fase sólida do headspace e cromatografia a gás acoplada à espectrometria de massa (HS-SPME-GC-MS foi desenvolvido e aplicado em amostras de cerveja brasileira. As extrações foram realizadas utilizando a fibra CAR/PDMS (carboxen/polidimetilsiloxano, com 15 minutos de tempo de equilíbrio e 90 minutos de exposição da fibra a 50 °C. O método foi linear na faixa de 0,02 e 4,0 μg.L-1, com coeficiente de correlação de 0,9994. Os limites de detecção e quantificação foram 0,01 e 0,02 μg.L-1, respectivamente. Foram obtidos 96,5% de recuperação e 4% de variação entre replicatas de amostras de cerveja fortificadas com 2,0 μg.L-1 de (E-2-nonenal. O m

  9. Identificação de compostos voláteis da cúrcuma empregando microextração por fase sólida e cromatografia gasosa acoplada à espectrometria de massas Identification of volatile compounds of turmeric using solid phase microextraction and gas chromatography coupled to mass spectrometry

    Directory of Open Access Journals (Sweden)

    Adriana R. Mata

    2004-03-01

    Full Text Available Compostos voláteis da cúrcuma (Curcuma longa L. cultivada no Brasil foram isolados por microextração por fase sólida. Os rizomas foram cozidos em solução de bicarbonato de sódio 0,1%, fatiados, secos e triturados. Visando estabelecer o sistema ideal para a microextração, fibras de polidimetilsiloxano de 100µm de espessura foram expostas ao headspace de frascos de 10mL. Estudou-se a influência das seguintes variáveis sobre o rendimento dos compostos voláteis obtidos: amostras em pó (0,1 a 1,0g e em solução (40mg/L, diferentes temperaturas (40 a 70ºC e tempos (2 a 20min de partição. O efeito da temperatura (210 a 240ºC e do tempo (3 e 5min de dessorção também foi avaliado. As melhores condições para a partição dos compostos voláteis foram 0,1g do pó, 70ºC e 5min. A temperatura de 220ºC e o tempo de 5 minutos foram os de maior eficiência para a dessorção. A cromatografia gasosa foi conduzida em coluna capilar, detecção por ionização de chama e identificação por espectrometria de massas. A análise dos espectros de massas obtidos para os nove compostos voláteis predominantes indicou a presença de ar-curcúmeno, ar-turmerona, zingibereno, beta-sesquifelandreno, sabineno, 1,8-cineol e 1,4-terpineol.Volatile compounds from turmeric (Curcuma longa L. cultived in Brazil were isolated by solid phase microextraction. The rhizomes were cooked in 0.1% sodium bicarbonate solution, sliced, dried and ground. Polydimethyldiloxanes fibers (100 mm diameter were exposed to the headspace of 10 mL flasks with the aim of establishing an ideal microextraction system. The influence of the following parameters on the volatile substances obtained was studied: powder samples (0.1 to 1.0 g and dissolved samples (40 mg/L, different temperatures (40 to 70ºC and partition periods (2 to 20 min. The effect of temperature (210 to 240ºC and time (3 to 5 min on desorption efficiency was also evaluated. Optimum conditions for the

  10. A gaseous scintillation counter filled with He{sup 3} for neutron spectrometry; Compteur a scintillateur gazeux rempli de {sup 3}He pour la spectrometrie des flux de neutrons; Gazovyj stsintillyatsionnyj schetchik napolnennyj He{sup 3} dlya spektrometrii potokov nejtronov; Contador de centelleador gaseoso cargado con helio-3 para la espectrometria neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Baldin, S A; Matveev, V V

    1962-04-15

    gaseoso, y se exponen los resultados de experimentos sobre el registro y la espectrometria de flujos neutronicos realizados mediante ese contador cargado con una mezcla de-10 por ciento de xenon y 9 por ciento de helio-3 a una presion de 20 atm. abs. Se proporcionan datos sobre la construccion del aparato de suministro que asegura el funcionamiento ininterrumpido del contador durante largo tiempo, proporciona las mezclas de gases necesarias a una presion de 60 atmosferas y permite proceder a una purificacion continua del gas. Se examinan, ademas, los resultados del estudio del poder de resolucion energetica y la linealidad del contador en funcion de la energia, su rendimiento con intensidades en campos gamma de hasta 3 roentgens/h, y algunas cuestiones relacionadas con la posibilidad de ampliar el intervalo energetico en el que pueden aplicarse los contadores de centelleador gaseoso cargados con helio-3. (author) [Russian] V doklade opisyvaetsya gazovyj agregat, gazovyj stsintillyatsionnyj schetchik, a takzhe rezul'taty ehksperimentov po registratsii i spektrometrii potokov nejtronov pri pomoshchi gazovogo stsintillyatsionnogo schetchika, napolnennogo smes'yu 10% ksenona i 90% geliya-3, pri obshchem davlenii 20 ata. Privodyatsya dannye ob ustrojstve gazovogo agregata, obespechivayushchego nepreryvnuyu rabotu schetchika v techenie dlitel'nogo vremeni, poluchenie neobkhodimykh smesej gazov s obshchim davleniem do 60 atm, i postoyannuyu ochistku gaza ot zagryaznenij. Krome togo v doklade obsuzhdayutsya rezul'taty issledovaniya ehnergeticheskogo razresheniya i linejnosti schetchika po ehnergii, ego rabotosposobnost' v gamma-polyakh moshchnost'yu do 3 r/chas, a takzhe voprosy, svyazannye s vozmozhnost'yu rasshireniya ehnergeticheskogo diapazona raboty gazovykh stsintillyatsionnykh schetchikov, napolnennykh geliem-3. (author)

  11. Application of SPCALC for chemical and thermodynamic speciation of fluids -example for wells LV-4A, LV-11 and LV-13, Las Tres Virgenes geothermal field, BCS; Aplicacion del SPCALC en la especiacion quimica y termodinamica de fluidos: ejemplo del caso de los pozos LV-4A, LV-11 y LV-13, del campo geotermico de Las Tres Virgenes, BCS

    Energy Technology Data Exchange (ETDEWEB)

    Viggiano Guerra, J.C.; Sandoval Medina, F.; Flores Armenta, M.C. [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: fernando.sandoval@cfe.gob.mx, E-mail: magaly.flores@cfe.gob.mx; Perez, R.J. [Universidad de Calgary (Canada); Gonzalez Partida, E. [Universidad Nacional Autonoma de Mexico, Centro de Geociencias, Mexico, D.F. (Mexico)

    2009-01-15

    + CO{sub 2}) if boiling occurs or is induced, for instance, by flashing. Reactions occurring during the process produce the rest of the observed minerals in rocks (illite+quartz{+-}epidote), although the balance diagrams do not truly represent the process due to the just-mentioned explanation. On the other hand the oversaturated phases, according to SPCALC, are mainly silica varieties (from quartz to chalcedony), a prediction that is confirmed by the silica scaling occurring at superficial installations. Calcite, on the contrary, is reported as unsaturated, an apparent contradiction with reality, which shows problematic calcite scaling produced during the well exploitation according to the same just-mentioned mechanism. It is therefore recommended to adjust the SPCALC calculations at the reservoir level to be able to prevent imminent calcite scaling. Chemical and multi-phase speciation by using SPCALC results are useful and practical, if results are interpreted carefully. [Spanish] El SPCALC es un excelente software recientemente adquirido por la Comision Federal de Electricidad (CFE) a traves de un contrato con la Universidad Nacional Autonoma de Mexico (UNAM) y la universidad de Calgary, Canada, mediante el cual se obtiene la especiacion quimica y multifasica de fluidos geotermicos. La metodologia consiste en el calculo de variables termodinamicas, tales como las actividades (a) y las fugacidades (f) de las especies quimicas, asi como los indices de saturacion (log Q/K) de las fases minerales del yacimiento, lo que implica que modela condiciones termodinamicas de yacimiento (pH entre otras cosas) contribuyendo asi a pronosticar incrustaciones y corrosion dado que tambien simula la tasa de corrosion de los fluidos. En este articulo se modelan fluidos que han percolado a traves de rocas granodioriticas cretacicas de los pozos LV-4A, LV-11 y LV-13 del campo geotermico de Las Tres Virgenes, BCS, haciendo uso del software mencionado a partir de sus analisis quimicos. Asi

  12. Digital filters in spectrometry; Filtros digitales en espectrometria

    Energy Technology Data Exchange (ETDEWEB)

    Barron B, J. I.; Hernandez D, V. M.; Vega C, H. R., E-mail: israel_176@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas (Mexico)

    2013-10-15

    In this work is presented the development and application of the digital signal processing for different multichannel analysis spectra. The use of the smoothing classic methods in applications of signal processing is illustrated by a filters discussion; autoregressive, mobile average and the ARMA filters. Generally, simple routines of lineal smoothing do not provide appropriate smoothing of the data that show the local ruggedness as the strong discontinuities; however the indicated development algorithms have been enough to leave adapting to this task. Four algorithms were proven: autoregressive, mobile average, ARMA and binomial methods for 5, 7, and 9 of data, everything in the domain of the time and programmed in Mat lab. (Author)

  13. Identificação e quantificação de voláteis de café através de cromatografia gasosa de alta resolução / espectrometria de massas empregando um amostrador automático de "headspace" Identification and quantification of coffee volatile components through high resolution gas chromatoghaph/mass spectrometer using a headspace automatic sampler

    Directory of Open Access Journals (Sweden)

    Leonardo César AMSTALDEN

    2001-01-01

    Full Text Available Usando um amostrador automático, os "headspaces" de três marcas comerciais de café torrado e moído foram analisados qualitativa e quantitativamente quanto a composição dos voláteis responsáveis pelo aroma através da técnica de cromatografia gasosa/espectrometria de massas. Uma vez que a metodologia não envolveu isolamento ou concentração dos aromas, suas proporções naturais foram mantidas, além de simplificar o preparo das amostras. O emprego do amostrador automático permitiu também boa resolução dos picos cromatográficos sem o emprego de criogenia, contribuindo para redução no tempo de análise. Noventa e um componentes puderam ser identificados, sendo que alguns compostos conhecidos como presentes em café como o dimetilsulfeto, metional e furfuril mercaptana não foram detectados. Os voláteis presentes em maior concentração puderam ser quantificados com o auxílio de dois padrões internos. A técnica se provou viável, tanto para caracterização como para quantificação de voláteis de café.Employing an automatic headspace sampler, the headspaces of three commercial brands of ground roasted coffee were qualitatively and quantitatively analyzed by gas chromatography / mass spectrometry. Since the methodology did not involve aroma isolation or concentration, their natural proportions were maintained, providing a more accurate composition of the flavors, and simplifying sample preparation. The automatic sampler allowed good resolution of the chromatographic peaks without cryofocusing the samples at the head of the column during injection, reducing analysis time. Ninety one compounds were identified and some known coffee volatiles, such as dimethyl sulphide, methional and furfuryl mercaptan were not detected. The more concentrated volatiles could be identified using two internal standards. The technique proved viable, for both characterization and for quantification of coffee volatiles.

  14. The effects of canopy cover on throughfall and soil chemistry in two forest sites in the Mexico City air basin; Los efectos de la cobertura de dosel en disminucion y la quimica del suelo en dos lugares de bosque en la cuenca de aire de la Ciudad de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Suarez, M. [Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICYT), San Luis Potosi, S.L.P. (Mexico)]. E-mail: marlin@ipicyt.edu.mx; Fenn, M.E. [United States Department of Agriculture Forest Service Pacific Southwest Research Station, Forest Fire Laboratory, Riverside, California (United States); Cetina-Alcala, V.M.; Aldrete, A. [Instituto de Recursos Naturales, Colegio de Postgraduados, Montecillo, Edo. de Mexico (Mexico)

    2008-01-15

    Throughfall and soil chemistry were compared in two sites with differing atmospheric deposition: Desierto de los Leones National Park (high atmospheric deposition) and Zoquiapan National Park (low atmospheric deposition). Throughfall fluxes of NO{sub 3}-, SO{sub 4}{sup 2}-, Ca, Mg and K were compared under two canopy cover types: Abies religiosa Schl. (fir) and Pinus hartwegii Lindl. (pine), in comparison with sites without cover canopy, e.g. forests clearings. Throughfall fluxes decreased in the following order: fir > pine > forest clearing. Nitrogen balance under canopy of fir and pine resulted in negative values for net throughfall of NH{sub 4}+ at Desierto de los Leones and Zoquiapan, while NO{sub 3}-, only resulted in negative values under canopy cover at the low deposition site. With few exceptions, concentrations of total C, N and S, soluble SO{sub 4}{sup 2}-, and Ca{sub 2}+ were higher in soil under fir canopies than under pine or in forest clearings. In polluted sites, the densely foliated fir canopies generally resulted in higher throughfall fluxes and soil accumulation of N, S and Mg compared to pine canopies or open areas. The elevated atmospheric depositions affect the functional process of forest ecosystem, particularly the throughfall and nutrients intern cycle, and these effects depend of the cover and present tree species. [Spanish] El escurrimiento foliar y la quimica del suelo fueron comparados en dos sitios con diferente deposito atmosferico: el Parque Nacional Desierto de los Leones (alto deposito atmosferico) y el Parque Nacional Zoquiapan (bajo deposito atmosferico). Se compararon los flujos de NO{sub 3}-, SO{sub 4}{sup 2}-, Ca, Mg y K en el escurrimiento foliar bajo el dosel de dos especies de arboles: Abies religiosa Schl. (oyamel) y Pinus hartwegii Lindl. (pino), en comparacion con sitios sin cobertura, es decir en claros del bosque. Los flujos disminuyeron en el siguiente orden: oyamel >pino >claros. El consumo de N del dosel resulto en

  15. Chemical tools: epoxic resins; Herramientas quimicas: resinas epoxidicas

    Energy Technology Data Exchange (ETDEWEB)

    Paz, S.; Pazos, M.; Prendes, P.

    1998-10-01

    Epoxy resins are very useful products for different applications in different fields. Due to the fact that they are a highly versatile products they can be considered as chemical tools. However the epoxy resins must be correctly formulated in order to obtain the final properties. In this article an easy and reliable method to optimise the energy formulation is presented. (Author)

  16. Chemical Changes Induced by Irradiation in Meats and Meat Components; Transformations Chimiques Provoquees par les Rayonnements dans les Viandes et Leurs Constituants; Khimicheskie prevrashcheniya v myasnykh produktakh i ikh sostavnykh chastyakh pod vozdejstviem oblucheniya; Alteraciones Quimicas Producidas por Irradiacion de las Carnes y de sus Componentes

    Energy Technology Data Exchange (ETDEWEB)

    Merritt, C. Jr. [Pioneering Research Division, United States Army Natick Laboratories, Natick, MA (United States)

    1966-11-15

    veau; il a egalement analyse les produits volatils de la degradation, par les rayonnements de plusieurs acides amines et proteines, de graisses animales, d'esters methyliques d'acide gras et de triglycerides. L'auteur compare les resultats de l'analyse des substances constitutives de la viande soumises a l'irradiation avec ceux obtenus par l'irradiation de la viande elle-meme et de fractions distinctes de viande, ce qui permet de determiner l'apport de chaque fraction a l'ensemble. Il postule des mecanismes expliquant la formation des elements volatils dans chacune de ces fractions ainsi que les interactions entre les sub- stances, intermediaires des differentes fractions. (author) [Spanish] El mal sabor y el mal olor originados por la irradiacion de la carne conservada son un obstaculo para su aceptacion. Se cree que este sabor y este olor desagradables se deben a.los compuestos quimicos volatiles producidos por las radiaciones en las moleculas de proteinas y lipidos. Se han analizado los compuestos volatiles por cromatografia en fase gaseosa a temperaturas sumamente bajas y con arreglo a un programa, para determinar las mezclas complejas obtenidas, y por espectrometria de masas con exploracion rapida, para identificar los componentes separados. Se han efectuado analisis minuciosos de las sustancias volatiles formadas por irradiacion en carne picada de vaca, cerdo, carnero, cordero y ternera, asi como de los productos volatiles de degradacion originados por las radiaciones en varios aminoacidos y proteinas, grasas animales, esteres metilicos de acidos grasos y trigliceridos. Los resultados del analisis de los componentes de la carne irradiados se comparan con los obtenidos irradiando la carne misma y distintas fracciones de ella. Se postulan los mecanismos de formacion de los componentes volatiles de cada fraccion y los de las interacciones de las fases intermedias correspondientes a distintas fracciones. (author) [Russian] Obluchenie razlichnyh sortov mjasa s cel

  17. Moderation of Neutrons Emitted by a Pulsed Source and Neutron Spectrometry Based on Slowing-Down Time; Ralentissement des Neutrons Emis par une Source Pulsee et Leur Spectrometrie en Fonction du Temps de Ralentissement; Zamedlenie nejtronov, ispuskaemykh impul'snym istochnikom, i spektrometriya nejtronov po vremeni zamedleniya; Moderacion de Neutrones Emitidos por una Pitente Pulsada y Espectrometria Neutronica Basada en el Tiempo de Frenado

    Energy Technology Data Exchange (ETDEWEB)

    Bergman, A. A.; Isakov, A. I.; Kazarnovskij, M. V.; Popov, Ju. P.; Shapiro, F. L. [Fizicheskij Institut Im. P.N. Lebedeva AN SSSR, Moskva, SSSR (Russian Federation)

    1965-08-15

    ralentissement, les variations de la section efficace des reactions neutroniques en fonction de l'energie et ils examinent les possibilites d'application et de perfectionnement qu'offre cette methode de spectrometrie. Ils etudient brievement les resultats de deux sortes de mesures spectrometriques: 1. Mesures precises portant sur les variations, en fonction de l'energie, des rapports entre les sections efficaces des reactions He{sup 3}(n, p), Li{sup 6}(n, {alpha}), B{sup 10}(n, {alpha}) et N{sup 14}(n, p). Le resultat le plus interessant de ces experiences a ete de decouvrir une composante negative constante de la section efficace de ces reactions et de trouver des indices laissant supposer l'existence d'un niveau excite de {sup 4}He. 2. Mesures de la variation que subissent les valeurs moyennes des sections efficaces de capture radiative des neutrons par les noyaux, en fonction de l'energie. Ces mesures, qui ont ete faites pour un grand nombre de substances, notamment pour divers isotopes, ont permis de constater l'existence de plusieurs niveaux de resonance a faible largeur neutronique, auparavant inconnues, et de determiner pour beaucoup de noyaux la valeur de la fonction de force relative a la capture des neutrons a moment orbital 1= 1. (author) [Spanish] Durante los ultimos diez anos se han venido realizando en el Instituto de Fisica p. N. Lebedev investigaciones sobre la moderacion no estacionaria de neutrones en medios pesados, el desarrollo de un metodo de espectrometria neutronica basada en la medicion del tiempo de frenado y la aplicacion de este metodo al estudio de la relacion entre la energia y las secciones eficaces de las reacciones nucleares producidas por neutrones con niveles energeticos de hasta 30 keV, En la presente memoria los autores pasan revista a dichos trabajos y analizan los resultados obtenidos. Despues de exponer brevemente la teoria de la moderacion y termalizacion no estacionarias de neutrones, los autores presentan los resultados de estudios

  18. Determination of Fallout Radionuclides in Environmental Samples by Gamma-Ray Spectrometry; Mesure Spectrometrique Gamma des Radionucleides de Retombee Presents dans des Echantillons du Millieu; Opredelenie radioizotopov radioaktivnykh osadkov v probakh iz okruzhayushchej sredy pri pomoshchi spektrometrii gamma-luchej; Determinacion, por Espectrometria Gamma, de los Radionuclidos de Precipitaciones en Muestras del Medio Ambiente

    Energy Technology Data Exchange (ETDEWEB)

    Ward, G. M.; Johnson, J. E.; Wilson, D. W. [Department of Animal Science, Colorado State University, Fort Collins, CO (United States)

    1965-10-15

    programme prepare pour la solution correspondant a la concentration de chacun des neuf nucleides mentionnes ci-dessus. Les auteurs ont utilise le meme programme pour resoudre la question de la teneur en {sup 137}Cs et en {sup 40}K du lait, de la viande et de l'urine, cette methode etant plus simple et les marges d'erreur plus reduites. (author) [Spanish] Desde mayo de 1962 los autores han venido reuniendo gran nfimero de muestras del medio ambiente en la granja de la Universidad del Estado de Colorado, a fin de estudiar el paso del {sup 137}Cs por una parte importante de la cadena alimentaria del hombre. Todas las muestras eran de baja actividad especffica y las determinaciones se hicieron con un especttometto de rayos gamma provisto de un cristal de Nal(Tl) de 8 pulg de diametro y 4 pulg de espesor, protegido de la actividad ambiente por una camara de paredes de acero de 12,7 cm de espesor y conectado a un analizador de amplitud de impulsos de 400 canales. Los autores procedieron al recuento directo, empleando una geometria constante, de la actividad de filtros de aire del tipo de almohadilla y de grandes muestras (1 kg) de forraje, grano y heces desecadas de bovidos. Las muestras de las precipitaciones se concentraron haciendolas pasar por columnas con resinas de intercambio cationico Dowex-50. Tambien se procedio al recuento de la actividad de muestras de leche, carne y orina contenidas en grandes recipientes anulares de Lucite. El {sup 137}Cs, el {sup 40}K, el {sup 131}I y el {sup 140}Ba-La fueron los unicos radionuclidos emisores de rayos gamma hallados en dichas muestras, ya que son los unicos productos de fision absorbidos en cantidades apreciables. Por otra parte, las demas muestras contenfan {sup 141,144}Ce, {sup 135}Sb, {sup 103,106}Ru, {sup 95}Zr-Nb y {sup 54}Mn. En estas muestras, reunidas en 1962 y 1963, solo era posible determinar con seguridad, por espectrometria gamma y durante un perfodo de unos 6 meses despues de recogida la muestra, el {sup 95}Zr

  19. Co-digestion of incubatory wastes and agroindustrial wastewaters: continuous phase; Co-digestao de residuos de incubatorio de aves e aguas residuarias agroindustriais: fase continua

    Energy Technology Data Exchange (ETDEWEB)

    Matter, Juliana M; Costa, Monica Sarollis S. de M.; Costa, Luiz A. de M.; Martins, Marcos F. Leal , [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil)

    2011-07-01

    The waste from poultry hatchery, one of the production chain of chicken, generate a considerable volume of material with high pollution potential. The aim of this study was to examine the feasibility of utilization of waste through anaerobic co-digestion. For testing we used 20 digesters, each with a capacity of 60L, simulating horizontal tubular digester. Five treatments were tested with 2% ST: T{sub 1}: + hatchery drained water equalization tank. T{sub 2}: Waste + hatchery water drained from the first anaerobic pond agribusiness. T{sub 3}: Waste hatchery fresh water + the first anaerobic pond of the hatchery. T{sub 4}: cool + hatchery residue remaining wastewater. T{sub 5} (Mixed): Waste of hatchery fresh water + the first anaerobic pond of the hatchery + swine wastewater. Were determined the potential for biogas production and methane and the methane percentage in biogas. The co-digestion was efficient treatment for the waste where treatments T{sub 4} and T{sub 5} the best medium for reaching potential of biogas production and methane. All treatments showed satisfactory percentage of methane in the biogas composition. (author)

  20. Anaerobic digestion of goat manure: bio-conversion of energy and bio fertilizer; Digestao anaerobica de dejetos de caprinos: conversor biologico de energia e biofertilizante

    Energy Technology Data Exchange (ETDEWEB)

    Canafistula, Francisco Jose Firmino; Carvalho, Paulo Cesar Marques de; Teixeira, Adunias dos Santos [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. Engenharia Eletrica], Emails: firmino@ufc.br, carvalho@dee.ufc.br, adunias@ufc.com

    2009-07-01

    This research aims at analyzing biogas produced by anaerobic digestion of goat excrements related to energy generation, in addition to analyzing the bio-fertilizer as a byproduct of the process. Therefore, new products are generated from semi-intensive and extensive of goats, increasing its economical and environmental viability of the activity. The biogas was applied as the fuel for an Otto cycle internal combustion engine of 5.5 HP used to drive a hydraulic pump that supplied water to an area of one hectare of pasture. In addition, the spreadsheet GDER was applied to compute the kWh cost of the following electricity sources: biogas from goat excrement, diesel, electrical grid, wind and solar. It was found tat the biogas can substitute 30% of the daily energy requirements, and one can state that 1 m{sup 3} of biogas is equivalent to 740 mL of gasoline. (author)

  1. Viability of cheese whey anaerobic digestion for residue treatment and energy consumption; Viabilidade da digestao anaerobica do soro de queijo para tratamento do residuo e producao de energia

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Thais H.M. [Universidade Metodista de Piracicaba (UNIMEP), SP (Brazil); Oliveira, Antonio Joaquim de [Sao Paulo Univ., Piracicaba, SP (Brazil). Escola Superior de Agricultura Luiz de Queiroz. Departamento de Ciencias e Tecnologia Agroindustrial

    1993-06-01

    This work was undertaken to evaluate the anaerobic digestion of cheese whey (68000 mg COD/l), without and with whey pH adjustment, in complete mixture semi-continuous laboratory reactors and temperature kept at 35{+-}1{sup 0} C. Cattle manure with 8% total solids was used as seed to the reactors. The experiment was carried out for a period of 100 days. The following analysis were carried out for the experimental control: volatile acidity, alkalinity, ph, volume of biogas produced and COD. The results of this work shows that the reactors fed whey without pH correction broke down due to the high accumulation of fatty acids whereas the reactors fed with corrected whey (pH 5,5 and 6,5) obtained a better balance. Nevertheless we can say that the instability of the process was influenced by the steam of the reactor feeding. (author). 18 refs, 1 fig, 3 tabs

  2. State-of-the-art of the development and appliance of anaerobic digestion in Brazil; Estagio de desenvolvimento e aplicacao da digestao anaerobica no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, Yukie Saito; Craveiro, Americo Martins [Instituto de Pesquisas Tecnologicas (IPT), Sao Paulo, SP (Brazil)

    1988-12-31

    This paper presents the up-to-date situation of both research and application of anaerobic digestion in Brazil. Concerning application, rural digesters have accounted around 7520 units and this number is expected to increase very slowly. For anaerobic treatment of industrial and domestic effluents, inversely, a rapid growth is expected for the near future. (author) 9 refs., 3 tabs.

  3. Methane production from anaerobic digestion: relation between theory and practice; Producao de metano a partir da digestao anaerobia: relacao entre teoria e pratica

    Energy Technology Data Exchange (ETDEWEB)

    Gervasoni, Ronald [Companhia de Saneamento do Parana (SANEPAR), Curitiba, PR (Brazil)], E-mail: ronaldg@sanepar.com.br; Cantao, Mauricio Pereira [Universidade Tuiuti do Parana (UTP), Curitiba, PR (Brazil)], E-mail: mauricio.cantao@utp.br

    2011-10-15

    Three calculation methodologies for methane production (UNFCCC, CENBIO and removed COD) were applied in sewage treatment plants, namely, ETE Ouro Verde and ETE Atuba Sul, both based on the use of upflow anaerobic sludge blanket (UASB). The theoretical results were compared with experimental values, with different discrepancy levels. The analysis of ETE Atuba Sul samples showed the presence of 34% of dissolved methane in the treated effluent. This value allows for the conclusion that the UNFCCC is the most appropriate estimation method for methane production in anaerobic sewage treatment plants. (author)

  4. Radioisotopes in the physical chemistry of corrosion processes and their inhibition; Les radioisotopes dans la chimie physique des processus de corrosion et de leur inhibition; Primenenie radioizotopov v fizicheskoj khimii protsessov korrozii i ikh tormozheniya; Los radioisotopos en la quimica fisica de los procesos de corrosion y de inhibicion

    Energy Technology Data Exchange (ETDEWEB)

    Cartledge, G H [Chemistry Division, Oak Ridge National Laboratory, Oak Ridge, TN (United States)

    1962-03-15

    periodico, es particularmente adecuado para algunos de estos estudios. Las ventajas do este elemento estriban, en sus propiedades nucleares. La memoria resume las propiedades quimicas de los compuestos de tecnecio y las compara con las de los compuestos correspondientes de {sup 51}Cr, de molibdeno y de wolframio, que con tanta frecuencia se emplean en el estudio de la inhibicion. La memoria describe seguidamente ciertos estudios experimentales como ejemplo de los usos a que se ha destinado el tecnecio en los trabajos de este tipo. Entre ellos menciona estudios empiricos de su accion como eficaz inhibidor de la corrosion del hierro, y observaciones de la actividad de superficie realizadas durante periodos largos de tiempo. Otros estudios efectuados con {sup 99}Tc y con {sup 131}I han demostrado la importancia de la adsorcion competitiva de iones en la determinacion de la cinetica de los procesos de corrosion y de inhibicion. Como tercer ejemplo, describe como las propiedades excepcionales del tecnecio han permitido distinguir claramente las contribuciones relativas del oxigeno de las del inhibidor oxidante en el mantenimiento de la pasividad. (author) [Russian] Sredi faktorov, vkhodyashchikh v fundamental'noe izuchenie ehlektrokhimicheskikh protsessov korrozii i tormozheniya, vydelyayutsya v chastnosti sleduyushchie: a) razlichnye vidy adsorbtsionnykh yavlenij; b) ionoobmennye svojstva passivnykh plenok; c) ehlektrokhimicheskaya kinetika kak anodnykh, tak i katodnykh protsessov, proiskhodyashchikh mezhdu metallom i korrozijnoj sredoj. Teper' pri pomoshchi radioizotopov mozhno provesti nekotorye issledovaniya ehtikh yavlyaenij, kotorye nevozmozhno osushchestvit' obychnymi sredstvami. Tekhnetsij, gomolog margantsa v periodicheskoj sisteme, okazalsya ves'ma podkhodyashchim dlya nekotorykh ehtikh issledovanij. Ego yadernye svojstva krajne interesny u ehtom otnoshenii. V doklade kratko izlagayutsya khimicheskie svojstva soedinenij tekhnetsiya, protivopostavlennye svojstvam

  5. Mass-Spectrometric Investigations of Isotopic Exchange Reactions of Gaseous Hydrocarbon Ions; Recherches, par Spectrometrie de Masse, sur les Echanges Isotopiques des Ions d'Hydrocarbures Gazeux; Mass-spektrometricheskie issledovaniya reaktsij izotopnogo obmena ionov gazoobraznogo uglevodoroda; Estudio del Intercambio Isotopico de Iones Hidrocarburo Gaseosos por Espectrometria de Masas

    Energy Technology Data Exchange (ETDEWEB)

    Wexler, S. [Argonne National Laboratory, Argonne, IL (United States)

    1965-10-15

    }{sup +} + H{sub 2}; D{sub 2}{sup +} + CH{sub 4} ( North-East-Arrow CH{sub 2}D{sup +} + H + DH); ( South-East-Arrow CHD{sub 2}{sup +} + H + H{sub 2}) auxquelles est due la diminution rapide de l'espece primaire avec l'addition du constituant oppose, doivent etre de l'ordre de grandeur des vitesses des reactions concurrentes respectives CH{sub 3}{sup +} + CH{sub 4} -> C{sub 2}H{sub 5}{sup +} + H{sub 2}; D{sub 2}{sup +} + D{sub 2} --> D{sub 3}{sup +} + D pour lesquelles l'auteur a mesure des sections efficaces de 27 x 10{sup -16} et 56 x 10{sup -16} cm{sup 2}/molecule respectivement. Ces sections efficaces correspondent a de tres grandes constantes de vitesse de 9.9 x 10{sup -10} and 4.0 x 10{sup -9} cm{sup 3} molecule/s. Les ions methyle enrichis en isotope doivent aussi reagir tres rapidement avec D{sub 2} et CH{sub 4} pour former l'espece marquee C{sub 2}H{sub 5}{sup +} . (author) [Spanish] El autor ha empleado tecnicas de espectrometria de masas 'de alta presion' para estudiar el intercambio de isotopos de hidrogeno en productos carbonados de reacciones ionico-moleculares. En observaciones hechas a presiones de aproximadamente 0,1 torr en la fuente, H{sub 2} + CH{sub 4}, D{sub 2} + CH{sub 4} y T{sub 2} + CH{sub 4}, de carga positiva comparados con los espectros de los componentes individuales, los espectros de mezclas pusieron de manifiesto que el CH{sub 3}{sup +} y los iones primarios de hidrogeno molecular reaccionan rapidamente con el otro componente de la mezcla de gases para crear, mediante una serie de reacciones consecutivas, especies ionicas secundarias y terciarias en las cuales tiene lugar un intenso intercambio de isotopos de hidrogeno. Cuando se agrega metano al D{sub 2}, las especies principales de deuterio, D{sub 2}{sup +} y D{sub 3}{sup +} desaparecen casi por completo, formandose en cambio grandes cantidades de C{sub 2}H{sub 4}D{sup +}, C{sub 2}H{sub 3}D{sub 2}{sup +} and C{sub 2}H{sub 2}D{sub 3}{sup +} . Se comprueba, asimismo, que el ion CH{sub 3

  6. Removal of Perchlorate from Water and Wastewater by Catalytic Hydrogen Gas Membrane Systems

    Science.gov (United States)

    2007-01-01

    Quimica, Serie A: Quimica Fisica e Ingenieria Quimica, 1984. 80(2): p. 219-25. Logan, B.E. and D. LaPoint, Treatment of Perchlorate- and Nitrate...ion at iridium electrodes. Ion concentration and solution pH effects. Anales de Quimica, Serie A: Quimica Fisica e Ingenieria Quimica (1985), 81(3

  7. Recent Methods in Crystal Spectrometry; Methodes Recentes de Spectrometrie a Cristal; 041d 041e 0412 042b 0415 041c 0415 0422 041e 0414 042b 041a 0420 0418 0421 0422 0410 041b 041b 0418 0427 0415 0421 041a 041e 0419 0421 041f 0415 041a 0422 0420 041e 041c 0415 0422 0420 0418 0418 ; Metodos Recientes de Espectrometria Cristalina

    Energy Technology Data Exchange (ETDEWEB)

    Iyengar, P. K. [Atomic Energy Establishment Trombay, Bombay (India)

    1965-06-15

    combinado con un detector, que permite ganar intensidad en las mediciones por dispersion inelastica. Una dificultad que suscita su empleo con muestras de dispersion coherente es la indeterminacion de la transferencia de impulso. Recientemente se han utilizado en trabajos de dispersion inelastica dos filtros combinados, con cortes diferentes, y un contador para detectar los neutrones retrodispersos por el segundo filtro, que forma una ventana. Esto permite mejorar la resolucion energetica y la definicion de la transferencia de impulso. Se presentan algunas mediciones relativas a las caracteristicas de este tipo de filtro. Aprovechando la definicion en vector de onda de los neutrones detectados, el filtro de ventana se ha utilizado con exito para determinar las curvas de dispersion de fonones en redes cristalinas. Como este instrumento biaxial sirve para los mismos fines que el triaxial, supone una simplificacion constructiva. Se ha aplicado con tal dispositivo el metodo de Q constante. Se presentan resultados de mediciones tipicas. El principal inconveniente de la espectrometria mediante cristales es que solo se utiliza un angulo de dispersion cada vez. Puede superarse empleando un espectrometro de varios brazos. Se describen las caracteristicas y empleo de un espectrometro de este tipo para medir la distribucion de la energia. La posibilidad de hacer funcionar todos los brazos del espectrometro segun el modo de Q constante supone una ventaja adicional para el estudio de muestras monocristalinas. Este procedimiento permitiria en el futuro aumentar considerablemente la velocidad de acopio de datos cuando se emplee la tecnica del espectrometro de cristal. (author) [Russian] Princip difrakcii na kristalle otkryvaet put' dlja prostogo raspredelenija jenergii medlennyh nejtronov. Odnako na kolichestvennoe opredelenie raspredelenija jenergij vljjajut razlichnye parametry, zavisjashhie ot struktury jelementarnoj jachejki kristallicheskogo monohromatora i geometricheskogo

  8. Characterization and classification of pequi trees (Caryocar brasiliense Camb. based on the profile of volatile constituents using headspace solid-phase microextraction - gas chromatography - mass spectrometry and multivariate analysis Caracterização e classificação de pequizeiros (Caryocar brasiliense Camb. baseadas no perfil de constituintes voláteis usando microextração em fase sólida no modo headspace - cromatografia a gás - espectrometria de massas e análise multivariada

    Directory of Open Access Journals (Sweden)

    Renata França Cassimiro Belo

    2013-02-01

    Full Text Available In order to determine the variability of pequi tree (Caryocar brasiliense Camb. populations, volatile compounds from fruits of eighteen trees representing five populations were extracted by headspace solid-phase microextraction and analyzed by gas chromatography-mass spectrometry. Seventy-seven compounds were identified, including esters, hydrocarbons, terpenoids, ketones, lactones, and alcohols. Several compounds had not been previously reported in the pequi fruit. The amount of total volatile compounds and the individual compound contents varied between plants. The volatile profile enabled the differentiation of all of the eighteen plants, indicating that there is a characteristic profile in terms of their origin. The use of Principal Component Analysis and Cluster Analysis enabled the establishment of markers (dendrolasin, ethyl octanoate, ethyl 2-octenoate and β-cis-ocimene that discriminated among the pequi trees. According to the Cluster Analysis, the plants were classified into three main clusters, and four other plants showed a tendency to isolation. The results from multivariate analysis did not always group plants from the same population together, indicating that there is greater variability within the populations than between pequi tree populations.A fim de determinar a variabilidade de populações de pequizeiro (Caryocar brasiliense Camb., compostos voláteis de frutos de dezoito árvores representando cinco populações foram extraídos por microextração em fase sólida no modo headspace e analisados por cromatografia a gás acoplada à espectrometria de massas. Setenta e sete compostos foram identificados, incluindo ésteres, hidrocarbonetos, terpenoides, cetonas, lactonas e álcoois. Vários compostos não haviam sido encontrados anteriormente no fruto. A quantidade total e a composição de voláteis variaram entre as plantas. O perfil volátil permitiu a diferenciação de todas as dezoito plantas, indicando que há um

  9. CUANTIFICACIÓN DE MERCURIO EN TERMOFORMADOS Y PELÍCULAS FLEXIBLES BIODEGRADABLES ELABORADAS A PARTIR DE YUCA (Manihot esculenta Crantz POR ESPECTROMETRÍA DE ABSORCIÓN ATÓMICA QUANTIFICAÇÃO DE MERCÚRIO EM TERMOFORMADOS E PELÍCULAS FLEXÍVEIS BIODEGRADÁVEIS ELABORADAS A PARTIR DE MANDIOCA (Manihot esculenta Crantz POR ESPECTROMETRIA DE ABSORÇÃO ATÔMICA QUANTIFICATION OF MERCURY IN THERMOFORMED AND FLEXIBLE FILMS BIODEGRADABLE MADE FROM CASSAVA (Manihot esculenta Crantz BY ATOMIC ABSORPTION SPECTROMETRY

    Directory of Open Access Journals (Sweden)

    ROBERTO JULIÁN DEL CASTILLO R

    2012-12-01

    Full Text Available Se cuantificó el contenido de mercurio en siete muestras de termoformados y seis de películas flexibles biodegradables, por espectrometría de absorción atómica con vapor frío; previamente a ésta cuantificación, se realizó la implementación y estandarización del método analítico, en el cual se determinaron los parámetros de calidad estadística (Límite de detección y de cuantificación, intérvalo lineal, sensibilidad de calibración, precisión y exactitud, que establecieron el rendimiento del método. Los termoformados se digestaron con una mezcla HNO3:HClO4, relación 3:1, durante 3 horas a 70°C y las películas flexibles por 45 minutos a 50°C. Las muestras se cuantificaron por el método de curva de calibración a 253,7 nm, obteniéndose concentraciones de mercurio en el rango de no detectable a 60 µg/L en termoformados y de no detectable a 6 µg/L en las películas flexibles.Quantificamos o teor de mercúrio em sete amostras de termoformados e seis películas flexíveis biodegradáveis por espectrometria de absorção atômica com vapor frio; antes de esta medida, realizamos a implementação e padronização do método analítico, na qual os parâmetros de qualidade estatística foram determinados (limite de detecção e quantificação, faixa linear, sensibilidade de calibração, precisão e exatidão, que estabeleceu o desempenho do método. O digestor é termoformado com uma mistura HNO3:HClO4, uma proporção de 3:1 durante 3 horas a 70°C e filmes flexíveis por 45 min a 50°C. As amostras foram quantificadas pelo método da curva de calibração 253,7 nm, resultando em concentrações de mercúrio na faixa de não detectável a 60 mg/L em termoformados e não detectável a 6mg/L em filmes flexíveis.The mercury content of seven thermoformed and six biodegradable flexible films samples were evaluated by atomic absorption spectrometry with cold vapor; before the experiments, the statistical quality parameters were

  10. Carragenana da epífita Hypnea musciformis obtida do cultivo experimental de Solieria filiformis em Flecheiras, Estado do Ceará, Brasil = Carragennan from Hypnea musciformis epiphyte obtained from Solieria filiformis experimental culture at Flecheiras, Ceará State, Brazil

    Directory of Open Access Journals (Sweden)

    José Ariévilo Gurgel Rodrigues

    2011-04-01

    Full Text Available O cultivo da rodoficea Solieria filiformis vem sendo desenvolvido na praia de Flecheiras, Estado do Ceara, como perspectiva de utilizacao sustentavel do recurso para biotecnologia, mas o crescimento de epifitas sobre a especie compromete seu bom crescimento. Desta forma, avaliou-se a eficiencia de duas metodologias (M I e M II noisolamento da Kappa-carragenana (ƒÈ-CAR da alga marinha vermelha Hypnea musciformis. A ƒÈ-CAR foi obtida mediante digestao proteolitica (M I ou agua quente (80‹C (M II. Os extratos foram analisados quanto a sua composicao quimica, seguido por cromatografia de troca ionica em coluna de DEAE-celulose usando um gradiente de NaCl. A atividade anticoagulante foi avaliada pelo teste do tempo de tromboplastina parcial ativada (TTPA, usando plasma humano normal e heparina (HEP padrao (193 UI mg-1. A diferenca nos rendimentos foi 4,28 } 0,26%% (p Solieria filiformis (Rhodophyceae culture is being developed at Flecheiras Beach, state of Ceara, Brazil, for its future sustainable use in biotechnology. However, epiphyte growth on the species jeopardizes suitable development. The efficiency of two methods (M I and M II in the isolation of kappa-carrageenan (ƒÈ-CAR from red marine alga Hypnea musciformis has been evaluated. ƒÈ-CAR was obtained by proteolytic digestion (M I or by hot water (80‹C(M II and extracts were analyzed with regard to their chemical composition and then by ion-exchange chromatography on DEAE-cellulose column with NaCl gradient. Anticoagulant activity was evaluated by the activated partial thromboplastine time (APTT test with common human plasma and standard heparin (HEP (193 IU mg-1. Yield difference reached 4.28 } 0.26%% (p < 0.05, and the lowest sulfate content was obtained with M I (17.00% when compared to that with M II (26.30%. Further, different chromatographic profiles were reported between the two methods. Whereas M I was efficacious in obtaining ƒÈ-CAR anticoagulants (2.67 IU mg-1

  11. Characterization of radioactive orphan sources by gamma spectrometry; Caracterizacion de fuentes huerfanas radiactivas por espectrometria gamma

    Energy Technology Data Exchange (ETDEWEB)

    Cruz W, H., E-mail: wcruz@ipen.gob.pe [Instituto Peruano de Energia Nuclear (PGRR/IPEN), Lima (Peru). Planta de Gestion de Residuos Radiactivos

    2013-07-01

    The sealed radioactive sources are widely applicable in industry. They must have a permanent control and must be registered with the Technical Office of the National Authority (OTAN). However, at times it has identified the presence of abandoned sealed sources unknown to the owner. These sources are called 'orphan sources'. Of course these sources represent a high potential risk because accidents can trigger dire consequences depending on your activity and chemical form in which it presents the radioisotope. This paper describes the process and the actions taken to characterize two orphan radioactive sources from the smelter a Aceros Arequipa. For characterization we used a gamma spectrometry system using a detector NaI(Tl) 3″ x 3″ with a multichannel analyzer Nucleus PCA-II. The radioisotope identified was cesium - 137 ({sup 137}Cs) in both cases. Fortunately, the sources maintained their integrity would otherwise have generated significant pollution considering the chemical form of the radioisotope and easy dispersion. (author)

  12. Design and fabrication of shielding for gamma spectrometry; Diseno y fabricacion de blindaje para espectrometria gamma

    Energy Technology Data Exchange (ETDEWEB)

    Mariano H, E

    1991-05-15

    To have a system of gamma spectrometry in the Radiological Mobile Unit No. 1 (UMOR-1) was designed and manufactured an armor-plating appropriate to this, to make analysis of radioactive samples in place in the event of a radiological emergency, besides being able to give support to the Management of Radiological Safety, and even to give service of sample analysis of other Institutions. (Author)

  13. Raman Spectroscopy with simple optic components; Espectrometria Raman con componentes opticos simples

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, Mario; Cunya, Eduardo; Olivera, Paula [Direccion de Investigacion y Desarrollo, Instituto Peruano de Energia Nuclear, Lima (Peru)

    2014-07-01

    Raman Spectroscopy is .a high resolution photonics technique that provides chemical and structural information of almost any material, organic or inorganic compound. In this report we describe the implementation of a system based on the principle of Raman scattering, developed to analyze solid samples. The spectrometer integrates an optical bench coupled to an optical fiber and a green laser source of 532 nm. The spectrometer was tested obtaining the Naphthalene and the Yellow 74 Pigment Raman patterns. (authors).

  14. Neutron spectrometry with organic scintillation detector; Espectrometria de nuetrones con cristales de centelleo organicos

    Energy Technology Data Exchange (ETDEWEB)

    Butragueno Casdo, J L

    1972-07-01

    This work describes a fast neutron spectrometer using a stilbene crystal as head detector with pulse shape discrimination (P.S.D.) to reject gamma background. Tre experimental procedure involves the P.S.D., the measurements to calibrate the spectrometer and the corrections for several factors, mainly the non-linear response of the stilbene. Results of the measurements with the reaction D{sup 2}(d,n)He{sup 3}, and with an Am-Be neutron source are presented. It is also presented the measurement of the spectrum of the fast reactor CCRAl-1. (Author) 17 refs.

  15. Laboratory of High resolution gamma spectrometry; Laboratorio de espectrometria gamma de alta resolucion

    Energy Technology Data Exchange (ETDEWEB)

    Mendez G, A.; Giber F, J.; Rivas C, I.; Reyes A, B

    1992-01-15

    The Department of Nuclear Experimentation of the Nuclear Systems Management requests the collaboration of the Engineering unit for the supervision of the execution of the work of the High resolution Gamma spectrometry and low bottom laboratory, using the hut of the sub critic reactor of the Nuclear Center of Mexico. This laboratory has the purpose of determining the activity of special materials irradiated in nuclear power plants. In this report the architecture development, concepts, materials and diagrams for the realization of this type of work are presented. (Author)

  16. Anaerobic digestion of cassava wastewater in fixed bed reactor using bamboo medium support; Digestao anaerobica de agua residuaria de fecularia em reator de leito fixo utilizando meio suporte de aneis de bambu

    Energy Technology Data Exchange (ETDEWEB)

    Watthier, Elisangela; Andreani, Cristiane L.; Silva, Jefferson L.G. [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil)], E-mail: eliswa@hotmail.com; Gomes, Simone D. [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil). Dept. de Recursos Hidricos e Saneamento Ambiental

    2012-11-01

    Cassava wastewater causes damage to the environment due to high organic loads and presence of cyanide and hydrocyanic acid. An alternative treatment anaerobic which add value for biogas production. To allow use of higher load sand reducing the TDH support means are used. This study aimed to evaluate the performance of the anaerobic treatment of liquid effluent of cassava industry, using bamboo as support media. The wastewater used was derived from starch factory located in Toledo. Was used PVC reactor with a diameter of 15 cm and length 90 cm. Were used as support means 52 bamboo rings and useful reactor volume 61. A total of 13 load increasing, from 1,675 to 15.158 g.L{sup -1}.d{sup -1}, until reaching the maximum load bearable. For each load data was collected for 15 days by daily samples at entrance and exit of the reactors. The samples were analyzed: DQO, alkalinity, volatile acidity and biogas production. There was a system instability in 12,394 g.L{sup -1}.d{sup -1}, with values of AV/AT above 0.5, but the system began to show signs of stability in the next load. The reactor showed biogas production up 1.57 L.L{sup -1}.d{sup -1}. (author)

  17. Anaerobic co-digestion cassava wastewater and crude glycerin for removal of COD and solid; Co-digestao anaerobica de manipueira e glicerina bruta para remocao de DQO e solidos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jefferson L.G.; Guerra Junior, Joao B. [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil)], E-mail: j.lg11@yahoo.com.br; Gomes, Simone D.; Mallmann, Larissa S. [Universidade Estadual do Oeste do Parana (CCET/PGEAGRI/UNIOESTE), Cascavel, PR (Brazil). Dept. de Recursos Hidricos e Saneamento Ambiental

    2012-11-01

    To be discarded into the environment, cassava wastewater, generated during the processing of the cassava root, needs to be dealt with trying to reduce its organic load and total solids, harmful to water bodies. As for crude glycerin, a byproduct of biodiesel production, need alternatives to its destination, because the cost to its purification is often not feasible, preventing its use by pharmaceutical and food industries. In this study we chose to anaerobic digestion to treat manipueira assessing the behavior of the reactor with the addition of glycerin. The reactor was constructed of PVC with 60cm long, 20cm in diameter and a volume of 8.38 L, and HRT was 5 days. Three treatments were applied: T1, only manipueira, T2 with 0.25% glycerol and T3, with 0.50%. The three treatments showed a great reduction of organic load (above 90%) and higher with the addition of 0.25% crude glycerine. The highest mean removal of solids and total volatile solids occurred in treatment with 0.50% crude glycerine, being 84.18% and 91.41% respectively. (author)

  18. Electricity by anaerobic digestion of vinasse from sugar cane. Technical profile, economic and environmental impacts of an option; Eletricidade por digestao anaerobia da vinhaca de cana-de-acucar. Contornos tecnicos, economicos e ambientais de uma opcao

    Energy Technology Data Exchange (ETDEWEB)

    Rego, Erik Eduardo; Moral Hernandez, Francisco del [Universidade de Sao Paulo (PIPGE/IEE/USP), SP (Brazil). Inst. de Eletrotecnica e Energia. Programa Interunidades de Pos-Graduacao em Energia

    2006-07-01

    In its first part this article brings up the growing importance of biomass in Brazilian and within the world energy scenario, especially due to the higher environmental consciousness related to the use of renewable energy sources. It also discusses about biomass sustainability and its myths. The Brazilian case shows that the usage of biomass is mixed to the use of sugar cane. The studies in this area are essentially directed to the production of ethanol and the burn of the solid waste production in steam generators. This article focuses on a specific liquid effluent product: the vinasse. The use of vinasse in agriculture as liquid fertilizer is not new. This article studies the technical, economical and environmental viability of the biogas production obtained from the anaerobic digestion of vinasse in order to generate electricity. The reactor under analysis is the UASB (Upflow Anaerobic Sludge Blanket) and a case study of a experimental process linked to alcohol production is used as a base to put side by side some points of view. Finally this article discusses how environmental regulations related to the effluent disposal (and their differences between two states in Brazil) were really trade-off issues in the decision making from the economical perspective. The combinations of the analysis (technical, economical and environmental) contributes for the global dimension of the alternative. (author)

  19. MODIFICACION QUIMICA DEL POLIPROPILENO Y SU POTENCIAL USO COMO AGENTE EXTRACTANTE DE IONES METALICOS.

    OpenAIRE

    PEREZ AMARO, LUCIA GABRIELA; PEREZ AMARO, LUCIA GABRIELA

    2008-01-01

    Es de interés en la presente tesis doctoral ampliar el campo de aplicación del polipropileno isotáctico homopolímero (PP) basándose en las propiedades mecánicas, químicas y el bajo costo de producción del polímero. Las excelentes propiedades mecánicas car 176p.

  20. EVALUACION FISICA MECANICA Y QUIMICA SOBRE CERRAMIENTOS UTILIZADOS POSTERIOR A UN INCENDIO

    Directory of Open Access Journals (Sweden)

    Valero, D.

    2015-06-01

    Full Text Available Esta investigación tuvo como objetivo evaluar el comportamiento ante el calor, de bloques de concreto aligerado y de poliestireno expandido de alta densidad, usados en losas y cerramientos en edificaciones prototipo. Se enmarca dentro de una investigación de campo, de carácter experimental y analítico-descriptivo, para lo cual se realizaron seis fases: recopilación de la información, caracterización físico-mecánica del revestimiento a utilizar, prototipos o módulos a ensayar, descripción de la sistemática del ensayo, caracterización físico-química de los materiales en estudio, y elaboración de recomendaciones de seguridad en caso de incendio. Se recopiló la información necesaria en materia de poliestireno expandido de alta densidad, y bloques aligerados con arcilla expandida mediante consultas de textos, manuales, normas, institutos, locales comerciales, publicaciones en internet, personal técnico capacitado con experiencia en el uso en obras de dichos materiales. La empresa especializada International Fire Services C.A. (IFSCA realizó el estudio requerido según normas. Entre los hallazgos relevantes se encontraron los altos valores de compuestos volátiles orgánicos durante la combustión del poliestireno expandido y la propiedad de los bloques aligerados con arcilla expandida como aislantes térmicos. This research is intended to evaluate the behavior of lightened concrete blocks and expanded high density polystyrene when exposed to heat, that are used in slabs and enclosures in prototype buildings. It is part of a field research, experimental and analytical-descriptive, for which six phases were carried out: collection of information, physical-mechanical character of coating to use, prototypes or modules to be tested, description of the scheme of testing, physical-chemical character of the materials under study and development of safety recommendations in case of fire characterization. The necessary information on expanded polystyrene high density, and lightweight blocks with expanded clay was collected through consultation of texts, manuals, standards, colleges, shops, online publications, trained personnel with experience using these materials. The specialized company International Fire Services C.A. (IFSCA conducted the study required under standards. Among the key findings there were the high levels of volatile organic compounds during combustion of expanded polystyrene and characteristics of the lightweight expanded clay blocks as thermal insulators were found.

  1. Feasibility of cogeneration systems in chemical industry; Viabilidade de sistemas de cogeracao em industria quimica

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Moises Henrique de Andrade; Balestieri, Jose Antonio Perrella [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia

    1998-07-01

    The increasing penetration of natural gas in the Brazilian energetic market, some industries as pulp and paper, chemical and that ones related to the food and beverage processes are some of the ones that are more interested in the cogeneration practice based on the burning of this fossil fuel. An analysis of a photographic chemical industry consumption data revealed that combined cycles and Diesel units were the most suitable for thermal following strategy, considering that the four compression chillers must be maintained, and steam or gas cycles in the case of a complete substitution for absorption chillers and the same strategy. The economic attractiveness was done according to the internal return rate and payback, revealing that the investment can be returned in short time. (author)

  2. Comportamiento de hormigones expuestos a condiciones naturales de alta agresividad quimica

    Directory of Open Access Journals (Sweden)

    Angel Oshiro

    2008-01-01

    Full Text Available Cuando se considera el hormigón en estado endurecido, un aspecto muy importante es la durabilidad del hormigón, la que puede depender del ambiente al que se expone o de causas internas del hormigón mismo. Este trabajo iniciado en el año 1976 por los ingenieros argentinos Oshiro y Rocha, centra su atención en el primer aspecto, presentando los resultados de la exposición de hormigones que estuvieron durante más de 20 años en un ambiente agresivo con elevado contenido de sulfatos y cloruros, geográficamente ubicado en Las Salinas Grandes, provincia de Córdoba, en el centro de la República Argentina. Los resultados difunden la experiencia de un caso real como un aporte para el medio científico y técnico, que permita tomar conciencia de las decisiones a tomar cuando el hormigón es expuesto a medios agresivos; permiten confirmar el deterioro químico progresivo de la pasta de cemento, en menor magnitud en hormigones con cemento puzolánico y la ventaja del empleo de bajas relaciones agua cemento y aditivo incorporador de aire en las principales propiedades del hormigón, controladas durante 20 años.

  3. Carcinogenese quimica por DMBA (7,12-dimethylbenzanthracene em camundongos femeas BALB/c: novos fatos

    Directory of Open Access Journals (Sweden)

    Krishna Duro de Oliveira

    2015-06-01

    Full Text Available Polycyclic aromatic hydrocarbons are known carcinogens used in rodent experimental models. In this study, the carcinogen DMBA (7,12-dimethylbenzanthracene was administered by gavage, diluted in corn oil, to female BALB / c mice at hebdomadary doses of 1 mg per animal for 1, 3, 6 or 9 weeks. Animals were weighed and monitored weekly until death. Remaining animals were euthanized at the age of 53 weeks. At necropsy, representative fragments of neoplasms were collected and routinely processed for histopathological analysis. Of all mice that received DMBA, 68.57% developed some type of tumor. Of the 70 mice treated with various doses of DMBA, 22 (31.43% developed mammary tumors. The adenoacanthoma was the most commonly (18.75% diagnosed histological type of breast cancer. Lung (15.71%, lymphoid tissue (11.43%, stomach (7.14% and skin (2.86% were also primary sites of tumor development. One third (33.33% of the mice receiving 1 mg of DMBA developed lung cancer. Therefore, the administration of DMBA was shown to be an efficient model of carcinogenesis in mice, especially for the study of breast cancer, when using the highest dose, and lung, when using the lowest dose. Carcinogenesis models have been used for several purposes in cancer research. These results represent new facts for a classic carcinogenesis model.

  4. Obtenção de gorduras low trans por interesterificação quimica

    OpenAIRE

    Miluska Castillo Caceres

    2008-01-01

    Resumo: As gorduras trans, principalmente presentes nos alimentos industrializados como biscoitos, gorduras para fritura, margarinas, entre outros, são resultados da hidrogenação parcial, processo utilizado pela indústria há mais de 100 anos Abstract:Trans fats, most contained within food industrialized and biscuits, fats for frying, margarine and others, are the result of partial hydrogenation, a process used by the industry for more than 100 years

  5. Efeito do pH sobre as caracteristicas fisico-quimicas do cream cheese.

    OpenAIRE

    Raquel Rossi Monteiro

    2004-01-01

    Resumo: Os objetivos deste trabalho foram padronizar uma condição de teste para avaliar a capacidade de derretimento do Cream cheese e avaliar o efeito do pH sobre a capacidade de derretimento, firmeza, equilíbrio físico-químico entre a matriz protéica e a fase aquosa do queijo e sobre a microestrutura do Cream cheese. Os queijos foram fabricados segundo metódo tradicional e a alteração do pH foi feita pós-processamento, através da exposição das amostras em atmosfera de hidróxido de amônio ou...

  6. On-line chemical cleaning of pipelines; Limpieza quimica de ductos en linea

    Energy Technology Data Exchange (ETDEWEB)

    Cross, Michael Brent [Brenntag Stinnes Logistics, Muelheim/Ruhr (Germany)

    2003-07-01

    The concern of efficiency and maintenance in the pipeline industry, due to fluids and sediments, has led the development of new methods of cleaning. Some methods of cleaning are described in this work with their advantages and disadvantages.

  7. ESTUDIO DE LA INTERRELACION ENTRE LA COMPOSICION Y QUIMICA DEL ROCIO CON LOS PROCESOS FOTOQUIMICOS ATMOSFERICOS.

    OpenAIRE

    Maria Angelica Rubio Campos; Ernesto Vicente Gramsch Labra; Eduardo Alejandro Lissi Gervaso; Maximiliano Araya Orellana; Marcela Shielien Cadiz Gin; Augusta Victoria Caroca Muñoz; Irene Eugenia Fuenzalida Farias; Cesar Antonio Gonzales Fernandez; Maria Jose Guerrero Duarte; Jimena Valentina Maira Solis; Elizabeth Salinas Donaire; Claudia Vega Vega; Natalia Zamorano Carrasco

    2004-01-01

    STUDY ON THE INTERRELATION BETWEEN COMPOSITION AND CHEMISTRY OF DEW AND ATMOSPHERIC PHOTOCHEMICAL PROCESSES The general objective of this project was to evaluate the impact of the different sources of radicals generated in the atmosphere of the city of Santiago, thus getting to know their relation to the chemical composition of dew, fog and rain. The hypothesis proposed in this study is that dews can include substances of photochemical origin, which might lead to the generation of smog...

  8. Multichannel analyzer for nuclear spectrometry with FPGA using Vivado; Analizador multicanal para espectrometria nuclear con FPGA utilizando Vivado

    Energy Technology Data Exchange (ETDEWEB)

    Garcia D, A.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico); Ordaz G, O. O.; Ibarra D, S. [Universidad de Cordoba, Campus de Rabanales, Carretera Nacional IV, km 396, 14014 Cordoba (Spain); Bravo M, I., E-mail: angelogarciad@hotmail.com [Universidad de Alcala, Departamento de Electronica, Campus Universitario s/n, 28805 Alcala de Henares, Madrid (Spain)

    2017-09-15

    The different applications of ionizing radiation have made this a very significant and useful tool, in turn can be dangerous for living beings if they are exposed to uncontrolled doses. However, due to its characteristics, cannot be perceived by the five senses, in such a way that in order to know the presence of it, radiation detectors and additional devices are required that allow to quantify and classify it. This is the case of the multichannel analyzer that is responsible for separating the different pulse heights that are generated in the detectors, in a certain number of channels; according to the number of bits of the analog to digital converter. The development or conditioning of nuclear technology has increased considerably due to the demand of the applications; therefore this allows developing systems that cover some commercial requirements, cost and volume in relation to the user needs. The objective of the work was to design and implement an intellectual property core (IP Core) which functions as a multichannel analyzer for nuclear spectrometry. For the IP Core design methodology, its components were created in VHDL hardware description language and packaged in the Vivado design suite, making use of resources such as the ARM processor cores that the Zynq chip contains. Likewise, for the first phase of the implementation, the hardware architecture was embedded in the FPGA and the application for the ARM processor was programmed in C language. For the second phase, the management, control and visualization of the results, a virtual instrument was developed in the LabView programming platform. The data obtained as a result of the development and implementation of the IP Core was observed graphically in a histogram that is part of the aforementioned virtual instrument. (Author)

  9. Evolutionary neural networks: a new alternative for neutron spectrometry; Redes neuronales evolutivas: una nueva alternativa para la espectrometria de neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz R, J. M. [Departamento de Electrotecnia y Electronica, Escuela Politecnica Superior, Av. Menendez Pidal s/n, 14004 Cordoba (Spain); Martinez B, M. R.; Vega C, H. R. [Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, Cipres 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Galleo, E. [Departamento de Ingenieria Nuclear, Universidad Politecnica de Madrid, Jose Gutierrez Abascal 2, 28006 Madrid (Spain)], e-mail: morvymm@yahoo.com.mx

    2009-10-15

    A device used to perform neutron spectroscopy is the system known as a system of Bonner spheres spectrometer, this system has some disadvantages, one of these is the need for reconstruction using a code that is based on an iterative reconstruction algorithm, whose greater inconvenience is the need for a initial spectrum, as close as possible to the spectrum that is desired to avoid this inconvenience has been reported several procedures in reconstruction, combined with various types of experimental methods, based on artificial intelligence technology how genetic algorithms, artificial neural networks and hybrid systems evolved artificial neural networks using genetic algorithms. This paper analyzes the intersection of neural networks and evolutionary algorithms applied in the neutron spectroscopy and dosimetry. Due to this is an emerging technology, there are not tools for doing analysis of the obtained results, by what this paper presents a computing tool to analyze the neutron spectra and the equivalent doses obtained through the hybrid technology of neural networks and genetic algorithms. The toolmaker offers a user graphical environment, friendly and easy to operate. (author)

  10. Methods of calculus for neutron spectrometry in proportional counters; Metodos de calculo para espectrometria de neutrones en contadores proporcionales

    Energy Technology Data Exchange (ETDEWEB)

    Butragueno, J L; Blazquez, J B; Barrado, J M

    1976-07-01

    Response functions for cylindrical proportional counters with hydrogenated gases have been determined, taking in account only wall effect, by means of two independent calculus methods. One of them is a Monte Carlo application and the other one analytica at all. Results of both methods have been compared. (Author)

  11. Plutonium determination in urine by techniques of mass spectrometry; Determinacion de plutonio en orina por tecnicas de espectrometria de masas

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez M, H. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Yllera de Ll, A., E-mail: hector.hernandez520@gmail.com [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Departamento de Medio Ambiente, Av. Complutense 22, 28040 Madrid (Spain)

    2013-10-15

    The objective of this study was to develop an analytic method for quantification and plutonium reappraisal in plane tables of alpha spectrometry be means of the mass spectrometry technique of high resolution with plasma source inductively coupled and desolvator Aridus (Aridus-Hr-Icp-Ms) and mass spectrometry with accelerator (AMS). The obtained results were, the recovery percentage of Pu in the plane table was of ∼ 90% and activity minimum detectable obtained with Aridus-Hr-Icp-Ms and AMS was of ∼ 3 and ∼ 0.4 f g of {sup 239}Pu, respectively. Conclusion, the results demonstrate the aptitude of the Aridus-Hr-Icp-Ms and AMS techniques in the Pu reappraisal in plane tables with bigger speed and precision, improving the values notably of the activity minimum detectable that can be obtained with the alpha spectrometry (∼ 50 f g of {sup 239}Pu). (author)

  12. Characterization of CT beams using Compton spectrometry; Caracterização de feixes de TC utilizando Espectrometria Compton

    Energy Technology Data Exchange (ETDEWEB)

    Terini, Ricardo A.; Nerssissian, Denise Y.; Campelo, Maria Carolina S.; Yoshimura, Elisabeth M., E-mail: rterini@if.usp.br [Universidade de São Paulo (LDRFM/USP), SP (Brazil). Lab. de Dosimetria das Radiações e Física Médica

    2017-07-01

    Obtaining the energy spectra of computed tomography (CT) X-ray beams is essential, helping to obtain parameters that characterize beam quality and equipment performance. However, CT photon fluxes are too high to have the spectra measured directly with common photon counting detectors. In this work, a Compton spectrometer was designed, with Al-Pb-Al collimators and shields, as well as a cadmium telluride (CdTe) detector to get the spectrum of CT beams, from the measurement of the spectrum of a beam scattered at 90 deg by a polymethyl-methacrylate (PMMA) rod. A MatLab® computer code was developed, using the Waller-Hartree formalism, to reconstruct the spectrum of the incident beam, from the measured scattered beam spectrum. Tests at IF-USP Laboratory of Radiation Dosimetry and Medical Physics with standard CT beams showed that the reconstructed spectrum is alike the directly measured beam. Shielding influence and scatterer thickness were investigated. The system was tested in measurements on a GE 690 CT scanner, showing practical positioning on the exam table, and alignment with CT lasers refined by scan projection radiography. Spectra obtained with the properly shielded system presented values of half-value layer (HVL) compatible with those measured in QC tests and kVp values with accuracy to evaluate the scanner voltage calibration. (author)

  13. Characterization of a tannin by NMR; Caracterizacao de um tanino elagico por espectrometria de ressonancia magnetica nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Antonio C.F.; Silva, Antonio J.R. da [Universidade Federal, Rio de Janeiro (Brazil). Nucleo de Pesquisas de Produtos Naturais

    1994-12-31

    This work presents the observations performed during the process of characterization of Geraniin, a crystalline tannin, which is able to undergo hydrolysis, isolated from Phyllanthus tennellus, a plant known in Brazil as `quebra-pedra`. The methodology is presented and the chemical analysis performed for the identification are presented and discussed. The obtained results are compared to the existing literature 5 refs., 2 figs., 8 tabs.

  14. Uso de espectrometria de massas em medidas eletroquímicas - a técnica de DEMS

    Directory of Open Access Journals (Sweden)

    Souza José Pio I. de

    2000-01-01

    Full Text Available The combination of cyclic voltammetry and on line mass spectrometry, called differential electrochemical mass spectrometry (DEMS, is already a well established method for on line identification and quantitative detection of the products and intermediates of electrochemical reactions. This article aims to show the principles of the method and how this technique have been used to study electrochemical problems such the electrocatalytic oxidation of organic molecules, as methanol and ethanol, at noble metal electrodes.

  15. Tracking and uncertainty in absorption spectrometry and atomic emission; Trazabilidad e incertidumbre en espectrometria de absorcion y emision atomica

    Energy Technology Data Exchange (ETDEWEB)

    Arvizu Torres, Maria del Rocio; Ramirez Cruz, Pedro [Centro Nacional de Metrologia (CENAM), Division de Materiales Metalicos, Area de Metrologia de Materiales, Departamento de Educacion Continua, El Marquez, Queretaro (Mexico)

    2008-04-18

    In this course it is described what methodology is, the measuring instruments and the importance of its calibration. The history of the International System of Units is described and what the meaning of tracking is. Also the general concepts of uncertainty in analytical measurements are shown, such as the measurements of central tendency and the variability measurements. [Spanish] En este curso se describe que es metodologia, los instrumentos de medicion y la importancia de calibrarlos. Se describe la historia del Sistema Internacional de Unidades y que es la trazabilidad. Tambien se presentan conceptos generales de incertidumbre en mediciones analiticas, como las medidas de tendencia central y las medidas de variabilidad.

  16. X-ray Spectrometry: Basic principles; Espectrometria de raios X: princípios básicos

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, R.M.; Teixeira, G.J.; Cardoso, R.S.; Peixoto, J.G.P., E-mail: rmcarvalho91@gmail.com [Instituto de Radioproteção e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2017-07-01

    The application of X rays requires a study of its spectrum. Intrinsic difficulties of the own method and of all the instrumentation necessary for the accomplishment of this practice were related. The objective was to demonstrate the use of a commercial spectrometer using at room temperature and compare it with spectra theoretically obtained by simulation. As an initial result was that both instrumentation is compatible to be used in an X-ray beam, with and without scattering material and its theoretical data were obtained. (author)

  17. The Conference on the Dynamics of Molecular Collisions Held at Snowbird, Utah on 14-19 July 1985.

    Science.gov (United States)

    1985-07-01

    Berkeley Lab. (701) 237-8906 Berkeley, CA 94720 S(415) 486-6 4 47 Dr. F. Borondo Dept. de Quimica Fisica y Quimica CuanticA Dr. Frank Budenholzer...F. Martin and M. Yaez. Departamento de Quimica Fisica y Quimica Cudntica Facultad de Ciencias. C-XIV. Universidad Aut6noma de Madrid. Cantoblanco

  18. Constraints on the Grueneisen Theory

    Science.gov (United States)

    2007-02-01

    TOMSK 634024 RUSSIA 5 DEPARTMENTO DE QUIMICA FISICA I FACULTAD DE CIENCIAS QUIMICAS UNIVERSIDAD COMPLUTENSE DE MADRID V G BAONZA...OVIEDO FACULTAD DE QUIMICA DEPARTMENTO DE QUIMICA FISICA Y ANALITICA E FRANCISCO AVENIDA JULIAN CLAVERIA S/N 33006 - OVIEDO

  19. A Note on the Application of the Extended Bernoulli Equation

    Science.gov (United States)

    1999-02-01

    SANTANDER SPAIN DEPARTMENTO DE QUIMICA FISICA FACULTAD DE CIENCIAS QUIMICAS UNIVERSIDAD COMPLUTENSE DE MADRID V G BAONZA M TARAVTLLO M CACERAS...UNIVERSIDAD DE OVIEDO FACULTAD DE QUIMICA DEPARTMENTO DE QUIMICA FISICA Y ANALITICA E FRANCISCO AVENIDA JULIAN CLAVERIA S/N 33006 - OVIEDO SPAIN

  20. International Conference on the Organometallic and Coordination Chemistry of Germanium, Tin and Lead (6th) Held in Brussels, Belgium on July 23-28, 1989

    Science.gov (United States)

    1989-07-28

    Molybdenumý-Tn and Molybdenum-M~ercury Bonds P08 Tudela. David Departamento de Quimica (C-VIII), Universidad Aut6noma de Madrid, 28049 Madrid, Spain The...Departamento de Quimica Inorgfnica. Facultad de QuImicas . Universidad Complutense de Madrid. Madrid, 28040. SPAIN. Previously it has been shown that...University ot New York at Albany Albany, NY 12222, USA Camipo Santillana, Jose Antonio, Mr. Dpto Quimica Inorganica, Pac. CC. Quimicas Universidad

  1. Sequential chemical extraction of heavy metals in a study of the chemical alteration of mine tailings at Ticapampa (Huaraz, Peru); Extraccion quimica secuencial de metales pesados en el estudio de alteracion quimica de relaves de mina en Ticapampa (Huaraz, Peru)

    Energy Technology Data Exchange (ETDEWEB)

    Jara Facundo, M. A.

    2011-07-01

    The upper reaches of the Rio Santa (Huaraz, Peru) are highly affected by the mining activities of generally small and very small mining companies located in two specific areas, Cordillera Blanca, and Cordillera Negra, with the largest mining claims located in the districts of Recuay and Ticapampa. To assess the mobility and bioavailability of heavy metals in the abandoned tailings pond belonging to the Alianza mining company in the district of Ticapampa, and to identify the fractions to which they are associated we applied a sequential chemical extraction. The results were compared with studies into their mineralogical characterization, a quantitative chemical analysis and a determination of potential acidity and potential neutralization by the ABA (acid-base accounting) method applied to samples of tailings. The sequential extraction procedure confirmed the mode of general alteration observed in the area through mineralogical studies: a relatively easy mobility of Pb, and Cd, and considerable immobility with regard to Ag, Cr and Co, as well as an intermediate mobility of Cu, Zn, and As. Significant cadmium and lead contents found in the most mobile fractions of the tailings may represent an environmental threat, bearing in mind the toxic nature of these elements. Despite the low mobility of arsenic, the total quantities of this element are so high that the waters of the Rio Santa are being affected. (Author) 22 refs.

  2. Chemical and physicochemical characterization of vermicompost from bovine manure and evaluation of competitive adsorption of cadmium and lead; Caracterizacao quimica e fisico-quimica de vermicomposto de esterco bovino e avaliacao da adsorcao competitiva por cadmio e chumbo

    Energy Technology Data Exchange (ETDEWEB)

    Lamim, Soraida Sozzi Miguel [Juiz de Fora Univ., MG (Brazil). Dept. de Quimica; Jordao, Claudio Pereira; Brune, Walter; Pereira, Jose Luis [Vicosa Univ., MG (Brazil). Dept. de Quimica

    1996-09-01

    The chemical and physicochemical characterization of vermicompost from bovine manure has been studied. It was examined the pH and cation exchangeable capacity (CTC), moistness, ash, organic carbon, total nitrogen, lignin, cellulose and metal concentrations, among other characteristics. The vermicompost was then applied to the retention and competition of metal pollutants (Cd and Pb) from metal nitrate solutions. The retention was affected by both the pH and time of adsorption, while the competitive character of these metals for the substrate was not relevant to each pH examined. (author) 46 refs., 4 figs., 7 tabs.

  3. 24. Annual meeting of the Brazilian Chemical Society. Chemistry in Latin America: integration and sustainable development. Book of Abstracts; 24. Reuniao anual da Sociedade Brasileira de Quimica. A quimica na America Latina: integracao e desenvolvimento sustentavel. Livro de Resumos

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    Some works about chemical synthesis, utilization of rare earths elements and the use of electrochemical analysis are show. Spectroscopic studies of complexes and organic composition of new chemical compounds are discussed. Structural studies aiming identification of recent natural products and preparation of compounds and metal complexes using nuclear magnetic resonance, X- ray diffraction and fluorescence methods are show. Some experimental and theoretical approach aiming results of level of accuracy on the news natural compounds, as well as aspects on environmental chemistry are presented.

  4. Forecast of physicochemical properties and chemical composition of gasoline from infrared spectra, using multivariate calibration; Previsao de propriedades fisico-quimicas e composicao quimica da gasolina a partir de espectros infravermelhos, utilizando calibracao multivariada

    Energy Technology Data Exchange (ETDEWEB)

    Cocco, Lilian Cristina; Yamamoto, Carlos Itsuo [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Lab. de Analise de Combustiveis Automotivos (LACAUTets)

    2008-07-01

    This work describes the attainment of mathematical models, applying multivariate calibration in infrared spectrum with ATR, from 128 gasoline samples with diverse chemical compositions, collected in a period of two and a half years. Infrared spectra had been used to assemble the input matrix for the modeling, whereas the standardized assays and gaseous chromatography had supplied the output matrices. Ninety samples were been used for training and 38 for testing. In order to calibrate chemical composition from chromatography, the techniques of mass spectrometry and chemical ionization were used to identify unknown substances and improve the fitting of the mathematical models. Two hundred and ninety substances were detected and identified, from which 100 were unknown. Six PLS/PCR models were attained to predict some properties as specific mass, Reid vapor pressure, T10, T50, T90 and PFE from distillation curve. Another six PLS/PCR models were attained to predict the amount of aromatics, paraffins, isoparaffins, naphthenes, olefins and oxygenates. In general, mathematical models were attained with good training fit, with correlation coefficients higher than 0,975 (T10) and reaching a maximum of 0,998 (naphthenes) and they are able to forecast an average chemical percentage and properties of interest from gasoline, with acceptable prediction errors. (author)

  5. Calculation of absorbed dose in water by chemical Fricke dosimetry; Calculo de dose absorvida na agua por dosimetria quimica Fricke

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Adenilson Paiva, E-mail: adenilson-fisica@hotmail.com.br [Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, RJ (Brazil); Meireles, Ramiro Conceicao [Fundacao do Cancer, Rio de Janeiro, RJ (Brazil)

    2016-07-01

    This work is the result of a laboratory activity performed in Radiological Sciences Laboratory (CRL), linked to the State University of Rio de Janeiro (UERJ). This practice aimed to determine the absorbed dose to water, through the primary calibration method called dosimetry Fricke, which consists of ferrous ions (Fe + 2) to ferric (Fe + 3), generated by water radiolysis products which is the structural change of water molecule caused by ionizing radiation. A spectrophotometer was used to extract data for analysis at a wavelength (λ) 304 and 224 nm with function of measuring the absorbance using bottles with irradiated and nonirradiated Fricke solution. (author)

  6. VARIABILIDAD Y RELACION ENTRE LAS PROPIEDADES ANATOMICAS, QUIMICAS Y LA APTITUD PULPABLE, EN CLONES DE EUCALYPTUS GLOBULUS.

    OpenAIRE

    RAMIREZ VIDAL, MAURICIO HERNAN; RAMIREZ VIDAL, MAURICIO HERNAN

    2008-01-01

    Se estudió la variación de la anatomía de la madera, variables biornétricas, aptitud pulpable y propiedades de la pulpa, en 14 clones de E. globulus de 7 años de edad, creciendo en un ensayo clonal en la zona de Arauco, región del Bio-Bio, Chile. Las Cara 61p.

  7. Efectos del procedimiento de extraccion en la organizacion estructural y composicion quimica de la matriz nuclear en plantas.

    OpenAIRE

    Cerezuela Rosique, María Angeles

    1991-01-01

    La matriz nuclear es una estructura núcleoesquel&ica ampliamente estudiada en sistemas animales, pero apenas existen trabajos que aborden el tema en sistemas vegetales, que poseen diferencias acusadas en la organización del citoesqueleto respecto a las células animales. Para profundizar en el conocimiento sobre el nucleoesqueleto y la matriz nuclear de plantas, hemos realizado un análisis de su organización ultraestructural, composición pohpeptídica y localización de ácidos ...

  8. ESTUDO DA ESTABILIDADE MICROBIOLOGICA E FISICO-QUIMICA DE POLPA DE CUPUAÇU DESIDRATADA EM ESTUFA

    Directory of Open Access Journals (Sweden)

    JULIANA DA SILVA DE ABREU MOREIRA

    2011-01-01

    moulds, all for triplicats. The results showed significant effect of interaction between dehydration time and storage to variables ºBrix and ascorbic acid. The water activity and the pH kept stable during all the period of storage, while the level of ascorbic acid reduces by the dehydration time and storage. The dehydration of in natura cupuaçu pulp in conventional oven is a practicable method of conservation and storage for 90 days.

  9. Chemical characterisation of zircon-cadmium sulfoselenide ceramic pigments; Caracterizacion quimica de pigmentos ceramicos a base de sulfoseleniuro de cadmio

    Energy Technology Data Exchange (ETDEWEB)

    Gazulla Barreda, M. F.; Rodrigo Edo, M.; Blasco Roca, E.; Orduna Cordero, M.

    2013-07-01

    The present paper addresses the development of a methodology that allows the complete chemical characterisation of zircon cadmium sulfoselenide ceramic pigments including minor and major elements. To develop the methodology, five zircon-cadmium sulfoselenide pigments with different hues were selected, studying the different measurement process steps, from sample preparation to the optimisation of the measurement of the different components of the pigments by spectroscopic techniques (WD-XRF and elemental analysis by combustion and IR detection). The chemical characterisation method developed was validated with synthetic standards prepared from the mixture of certified reference materials and pure oxides because no certified referenced materials of this type of pigments were commercially available. The developed method can be used for a complete chemical characterization of zircon-cadmium sulfoselenide ceramic pigments with a very low uncertainty for all the elements analysed. (Author)

  10. EVALUACIÓN QUIMICA DE LA FIBRA EN SEMILLA, PULPA Y CÁSCARA DE TRES VARIEDADES DE AGUACATE

    Directory of Open Access Journals (Sweden)

    ADELA MARÍA CEBALLOS P

    Full Text Available El sector agropecuario colombiano requiere integrarse al sector agroindustrial para aumentarle valor a sus productos y residuos. Utilizar residuos agrícolas y agroindustriales como materias primas para obtener metabolitos secundarios es tema de interés en investigación y busca dar respuestas al uso de esos residuos, mediante desarrollo de tecnologías aplicables al entorno colombiano. Se valoraron cáscara, semilla y pulpa de aguacate variedades Booth8, Trinidad y Papelillo en estados de madurez fisiológica (MF y consumo (MC. Se hizo caracterización bromatológica, contenido de fibra como carbohidratos solubles (CHOS, lignina LG, celulosa y hemicelulosa (CEL y HEMICEL y fibra bruta (FB según (Tappi Methods 1993, 1998, AOAC, 2001. Los resultados fueron analizados mediante ANOVA (P < 0,05 utilizando SAS V9.1. Los CHOS en los dos estados de madurez y para las tres variedades variaron entre 12-38% cáscara, 20-35% pulpa y 17-35% semilla; CEL y HEMICEL 8-50% cáscara, 7-26% pulpa, 1-5% semilla, los cuales pueden ser útiles como complementos de procesos biotecnológicos. La pulpa de las tres variedades tiene alto valor nutricional por sus contenidos de proteína, fibra y minerales. La composición de la cáscara y semilla podrían ser importantes para suplementos de dieta animal o como recuperador de suelos para la producción agrícola

  11. Chemical and colour quenching in liquid scintillation counting; Estudio de la extincion quimica y por color en centelleo liquido

    Energy Technology Data Exchange (ETDEWEB)

    Scott, P E; Grau, A

    1987-07-01

    Chemical and colour quenching for H-3 and C-14 was studied. The method includes spectral analysis of colouring agents; methyl red, (4'-dimethylamine-azobenzene 2-carboxylic acid) dimethyl yellow (4'-dimethylamine-azobenzene) and malachite green (methane, bis .(4-dimethyl aminophenyl) - (phenyl)). External standard channels ratio was applied for the liquid scintillation counting of samples. The introduction of an isolated external standard seems to be a strong tool for the correction of chemical and colour quenching curves. (Author) 12 refs.

  12. Chemical and colour quenching in liquid scintillation counting; Estudio de la extincion quimica y por color en centelleo liquido

    Energy Technology Data Exchange (ETDEWEB)

    Scott, P. E.; Grau, A.

    1987-07-01

    Chemical and colour quenching for H-3 and C-14 was studied. The method includes spectral analysis of colouring agents; methyl red, (4'-dimethylamine-azobenzene 2-carboxylic acid) dimethyl yellow (4'-dimethylamine-azobenzene) and malachite green (methane, bis .(4-dimethyl aminophenyl) - (phenyl)). External standard channels ratio was applied for the liquid scintillation counting of samples. The introduction of an isolated external standard seems to be a strong tool for the correction of chemical and colour quenching curves. (Author) 12 refs.

  13. COMPOSICIÓN QUIMICA Y ACTIVIDAD ANTIFOULING DE LA FRACCION LIPIDICA DE LA ESPONJA MARINA Cliona tenuis (Clionidae

    Directory of Open Access Journals (Sweden)

    Leonardo Castellanos

    2009-04-01

    Full Text Available Normal 0 21 false false false st1\\:*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} Del extracto orgánico de la esponja marina Cliona tenuis, recolectada en las Islas del Rosario (Colombia, Mar Caribe, fue obtenida la fracción lipídica, la cual presentó propiedades antifouling en pruebas en campo. Esta fracción fue separada por CC sobre gel de sílice hasta obtener fracciones de ésteres metílicos, glicéridos, glicolípidos, fosfolípidos y ácidos grasos libres, las cuales fueron identificadas por CCD y técnicas de dereplicación (RMN 1H y 13C. Posteriormente, las fracciones de glicéridos, glicolípidos y fosfolípidos fueron hidrolizadas y los ácidos obtenidos, junto con los provenientes de la fracción de ácidos grasos libres, fueron transformados en ésteres metílicos y todos se analizaron por CGAR-EM. Para ubicar las insaturaciones y ramificaciones, los ésteres metílicos se transformaron luego en sus correspondientes pirrolididas, las cuales también se analizaron por CGAR-EM. El estudio cromatográfico (valores de ECL y de los espectros de masas de los ésteres metílicos y de sus derivados pirrolididas permitió identificar 81 ácidos grasos diferentes, de los cuales no habían sido previamente reportados: los ácidos 4,8-hexadecadienoico, 11-metil-4,10-octadecadienoico, 6,9,12,14-icosatetraenoico, y 6,9,12,14,17-icosapentanoico.

  14. Chemical analysis of superconductor material by Rietveld method; Analise quimica de material superconductor atraves do metodo de Rietveld

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Junior, E.S.; Gomes Junior, G.G.; Ogasawara, T., E-mail: georges@metalmat.ufrj.b [Universidade Federal do Rio de Janeiro (COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Dept. de Eng. Metalurgica e Materiais; Bispo, E.R.; Polasek, A. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil); Amorim, H.S. [Universidade Federal do Rio de Janeiro (IF/UFRJ), RJ (Brazil). Inst. de Fisica

    2010-07-01

    Among the main superconducting systems, the system Bi-Sr-Ca-Cu-O is extremely important because it presents two stages of high superconducting critical temperature. To manufacture samples of the superconducting phase (Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}Ox (Bi-2223) were used oxides and carbonates of high purity. The mixture was calcined and sintered for 100-200h in air. To characterize the material we used X-ray diffraction, SEM / EDS and measurement of critical temperature (Tc). The Rietveld method was used for structure refinement, and quantification of phases and to estimate the chemical composition of samples in order to obtain greater control of chemical composition using only the data of X-ray diffraction. The results were compared with the refinement results of X-ray fluorescence and was observed a discrepancy of about 8%. This result indicates that the Rietveld method can be an interesting alternative to perform chemical analysis. (author)

  15. Influence of iodine chemistry on source term assessment; Influencia de la quimica del yodo en la estimacion del termino fuente

    Energy Technology Data Exchange (ETDEWEB)

    Herranz Puebla, L E; Lopez Diez, I; Rodriguez Maroto, J J; Martinez Lopez-Alcorocho, A

    1991-07-01

    The major goal of a phenomenology analysis of containment during a severe accident situation can be spitted into the following ones: to know the containment response to the different loads and to predict accurately the fission product and aerosol behavior. In this report, the main results coming from the study of a hypothetical accident scenario, based on LA-4 experiment of LACE project, are presented. In order to do it, several codes have been coupled: CONTEMPT4/MOD5 (thermohydraulics), NAUA/MOD5 (aerosol physics) and IODE (iodine chemistry). It has been demonstrated the impossibility of assessing with confidence the Source Term if the chemical conduct of some radionuclides is not taken into account. In particular, the influence on the iodine retention efficiency of the sump of variables such as pH has been proven. (Author)12 refs.

  16. Radiation chemical dosimetry by means of nitrate-nitrite; Dosimetria quimica de la radiacion aplicacion del sistema nitrato-nitrito

    Energy Technology Data Exchange (ETDEWEB)

    Tormo Ferrero, M J

    1977-07-01

    The different chemical systems used in dosimetry and the selection criteria for them are described. The general topics in dosimetry with alkali nitrates as well as the phenomena occurring in their radiolysis are also treated. The possibility of application in dosimetric areas useful in radiosterilization and industrial processes is studied too. (Author) 22 refs.

  17. Drogas na adolescencia : analise do uso de substancia quimicas entre adolescentes estudantes de escolas publicas e particulares de Campinas, SP

    OpenAIRE

    Maria Alice de Araujo Armani

    2007-01-01

    Resumo: Objetivo: Pesquisar, entre adolescentes de diferentes níveis sócio-culturais, estudantes de escolas públicas e privadas, uso de medicações específicas (fórmulas laboratoriais que visam emagrecimento, inibidores do apetite, ?orlistat?, anabólicos e esteróides, laxantes, diuréticos), tabagismo, consumo de bebidas alcoólicas, início de vida sexual, prevenção de gestações e DST e utilização de métodos anticoncepcionais. Métodos: Foi realizada uma pesquisa entre adolescentes estudantes do...

  18. Chemistry characterization and samples beryllium process impurity determination; Caracterizacao quimica e determinacao de impurezas de amostras de processo de berilio

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Leonel Mathry de

    1992-12-01

    Brazil is the greatest world producer of beryl (3 Be O.Al{sub 2}O{sub 3}.6SiO{sub 2}) and has recently begun to produce beryllium compounds by means of a pilot plant constructed at Governador Valadares city (Minas Gerais - Brazil). The aim of this work was the determination of trace level impurities and macro constituents in the tenth % range to support analytical control process of plant production and characterization of beryllium compounds. The impurities separations and purification process was developed by two steps procedure. The first one using EDTA complexation has separated and reduced some impurities to less than 1 {mu}g/ml level. In the second one it was used a chelating resin (Chelex 100) and the separation efficiency was about 75 to 97 % related with the element tested. High pure berylium oxide standard was obtained from purification of Be(OH)2. The R X fluorescence presented only traces of Cu and Si < 1 % Fe and Mn, Zn, Ca, Al, Na and S were completely removed. The beryllium content was determined by direct atomic emission spectroscopy in argon plasma (Dcp) and compared with classic gravimetric method as Be O. The results were in agreement (49,2+/-0,2 % and 48,3+/-0,1 % respectively) between 95 % of confidence. A low temperature gravimetric method for beryllium determination was also studied using Oxine with microwave furnace. A total of 24 elements including macro and trace level were determined by Dcp and/or spectrophotometric methods. The Be/B separation was studied using anionic resin in poly alcohols medium. A more detailed study of equilibrium conditions is necessary. This work was realized at Laboratorio de Analise Mineral (LAM) of Comissao Nacional de Energia Nuclear - Rio de Janeiro (CNEN). (author)

  19. Physico-chemical evaluation of radiation effects on apple juice; Avaliacao fisico-quimica do suco de maca irradiado

    Energy Technology Data Exchange (ETDEWEB)

    Blumer, Lucimara; Domarco, Rachel E.; Spoto, Maria H.F.; Walder, Julio M.M.; Matraia, Clarice [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)

    1997-12-01

    Gala and Fuji varieties apple`s juice were clarified with enzyme and irradiated aiming to extend the shelf-life without conservants and chemical additives. The juices were analysed for soluble solids, titrable acidity, pH and color. Results showed effect of storage periods in soluble solids, pH and color. The variety and storage period modified the titrable acidity. The pH was altered by irradiation dose and the storage period. (author). 9 refs., 6 figs.

  20. 76 FR 42113 - Purified Carboxymethylcellulose From Mexico: Final Results of Antidumping Duty Administrative Review

    Science.gov (United States)

    2011-07-18

    ..., 2011) (Preliminary Results). The review covers one producer/ exporter, Quimica Amtex S.A. de C.V. The..., through June 30, 2010, is as follows: Weighted- Producer/exporter average margin (percentage) Quimica...

  1. International Symposium on Gas Kinetics (11th) Held in Assisi (Perugia), Italy on 2-7 September 1990. Book of Abstracts

    Science.gov (United States)

    1990-09-07

    CROSSED-BEAM CONDITIONS L. Bafiares and A. Gonz’a1ez Urefia Departamento de Quimica Fisica. Facultad de Quimica . Universidad Complutense de Madrid. 28040...Departamento de Quinica Fisica, Universidad del Pais Vasco, Bilbao, Spainand J.M.Alvariiio, Departamento de Quimica Fisica, Universidad de Salamanca...ilbao (Spain) Jesus Matcos, Dcparlamenlo de Quimnica Fisie:n, Fnrullad de Quimica , Salamanca (Spain) Antonio Lagani, Dipareimento di Chirnica

  2. Application of electron ionization mass spectrometry for mulungu alkaloid analysis; Aplicacao de espectrometria de massas com ionizacao por eletron na analise de alcaloides do mulungu

    Energy Technology Data Exchange (ETDEWEB)

    Feitosa, Luis Guilherme Pereira; Guaratini, Thais; Lopes, Joao Luis Callegari; Lopes, Norberto Peporine [Universidade de Sao Paulo (FCFRP/USP), Ribeirao Preto, SP (Brazil). Fac. de Ciencias Farmaceuticas de Ribeirao Preto. Dept. de Quimica e Fisica; Bizaro, Aline Cavalli; Silva, Denise Brentan da, E-mail: npelopes@fcfrp.usp.br [Incubadora SUPERA, Ribeirao Preto, SP (Brazil). Lychnoflora Pesquisa e Desenvolvimento em Produtos Naturais

    2012-07-01

    Erythrina verna is a medicinal plant used to calm agitation popularly known as mulungu. We purchased the barks of E. verna from a commercial producer and analyzed the alkaloid fraction of the bark by CG-MS and HRESI-MS. Five erythrinian alkaloids were identified: erysotrine, erythratidine, erythratidinone, epimer, and 11-hydroxyeritratidinone. Here we report the compound 11-hydroxyeritratidinone for the first time as a natural product. (author)

  3. A new computation tool for neutron spectrometry and dosimetry; Una nueva herramiento de computo para la espectrometria y dosimetria de neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Martinez B, M. R.; Ortiz R, J. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Av. Ramon Lopez Velarde No. 801, Col. Centro, Zacatecas (Mexico)], e-mail: mrosariomb@yahoo.com.mx

    2009-10-15

    By using the integrated accounts of spectrometric system of Bonner spheres is possible to reconstruct the neutron spectrum using various methods such as: Monte Carlo, the parameterization and iterative methods. The response matrix, counting rates and neutron spectrum are intimately related through the integral-differential of Fredholm of first type. however, the weight of Bonner spheres system, the procedure of spectra reconstruction, the need of a expert user, the high time consumption, the need to use a reconstruction code (BUNKI, SAND, among others) and the spectrum resolution, are some of problems that this system presents. The above difficulties have motivated the development of complementary procedures such as maximum entropy, genetic algorithms and artificial neural networks. In recent years, using neural network technology has become an alternative procedure in the nuclear science research area, considering a replacement for classical techniques used for years. In previous works, was used a new method called robust design methodology of artificial neural networks, to construct various network topologies capable of solving the problems of neutron spectrometry and dosimetry, however noted that not exist tools for end-user that allow test and validate the designed networks. This paper presents the development of a software for neutronic spectrometry and dosimetry, based on information extracted from an artificial neural network designed in previous work, through the robust design methodology of artificial neural networks with the following characteristics: was designed in a user graphical interface easy to use, speed on the application execution, unlike other deconvolution codes, not is necessary to select and initial spectrum for spectrum reconstruction, as an additional element to this tool, besides spectrum, the calculation is performed simultaneous of 13 equivalent dose from just counting rates from a spectrometric system of Bonner spheres. (Author)

  4. Neutron spectrometry and dosimetry by means of evolutive neural networks; Espectrometria y dosimetria de neutrones por medio de redes neuronales evolutivas

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz R, J.M.; Martinez B, M.R.; Vega C, H.R. [UAZ, Av. Ramon Lopez Velarde Num. 801, 98000 Zacatecas (Mexico)

    2008-07-01

    The artificial neural networks and the genetic algorithms are two relatively new areas of research, which have been subject to a growing interest during the last years. Both models are inspired by the nature, however, the neural networks are interested in the learning of a single individual, which is defined as fenotypic learning, while the evolutionary algorithms are interested in the adaptation of a population to a changing environment, that which is defined as genotypic learning. Recently, the use of the technology of neural networks has been applied with success in the area of the nuclear sciences, mainly in the areas of neutron spectrometry and dosimetry. The structure (network topology), as well as the learning parameters of a neural network, are factors that contribute in a significant way with the acting of the same one, however, it has been observed that the investigators in this area, carry out the selection of the network parameters through the essay and error technique, that which produces neural networks of poor performance and low generalization capacity. From the revised sources, it has been observed that the use of the evolutionary algorithms, seen as search techniques, it has allowed him to be possible to evolve and to optimize different properties of the neural networks, just as the initialization of the synaptic weights, the network architecture or the training algorithms without the human intervention. The objective of the present work is focused in analyzing the intersection of the neural networks and the evolutionary algorithms, analyzing like it is that the same ones can be used to help in the design processes and training of a neural network, this is, in the good selection of the structural parameters and of network learning, improving its generalization capacity, in such way that the same one is able to reconstruct in an efficient way neutron spectra and to calculate equivalent doses starting from the counting rates of a Bonner sphere spectrometric system. (Author)

  5. In-situ gamma spectrometry method for determination of environmental gamma dose; Metodo de espectrometria gamma in situ para determinacao de dose gama ambiental

    Energy Technology Data Exchange (ETDEWEB)

    Conti, Claudio de Carvalho

    1995-07-15

    This work tries to establish a methodology for germanium detectors calibration, normally used for in situ gamma ray spectrometry, for determining the environmental exposure rate in function of the energy of the incident photons. For this purpose a computer code has been developed, based on the stripping method, for the computational spectra analysis to calculate the contribution of the partial absorption of the gamma rays (Compton effect) in the active and nonactive parts of the detector. The resulting total absorption spectrum is then converted to fluence distribution in function of the energy for the photons reaching the detector, which is then used to calculate the exposure rate or kerma in air. The unfolding and fluency convention parameters are determined by detector calibration using point gamma sources. The method is validated by comparison of the results against the calculated exposure rate at a point of interest for the standards. This method is used for the direct measurement of the exposure rate distribution in function of the energy at the site, in situ measurement technic, leading to rapid results during an emergency situation and also used for indoor measurements. (author)

  6. Instrumental analysis of low level of Cs-137 in marine samples by gamma spectrometry; Analise instrumental de baixos niveis de Cs-137 em amostras marinhas por espectrometria gama

    Energy Technology Data Exchange (ETDEWEB)

    Figueira, Rubens C.L.; Silva, Luiz R.N.; Figueiredo, Ana M.G.; Cunha, Ieda I.L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica

    1997-12-31

    An instrumental method for low level Cs-137 analysis in marine samples is presented. The method consists in the detector calibration, as well as, determination of detector counting efficiency, accumulative counting of both background and sample and smoothing of 661.6 keV photopeak. The methodology was applied in reference samples and in sediments samples of south Brazilian coast 11 refs., 6 figs., 4 tabs.; e-mail: figueira at net.ipen.br

  7. Determination of Radium 226 in mexican phosphate fertilizers and gypsum by gamma spectrometry.; Determinacion de Radio 226 en fertilizantes fosfatados y en yeso mediante espectrometria gamma.

    Energy Technology Data Exchange (ETDEWEB)

    Godinez A, M C

    1996-12-31

    The {sup 226} Ra isotope was determined in 17, 20 and 46% m/m phosphate fertilizers and gypsum. The samples of the fertilizers were dissolved in 10% v/v nitric acid solutions. The barium sulphate method was used for the precipitation of {sup 226} Ra. On the other hand, alkaline fusion method was used to separate the {sup 226} Ra from gypsum. The results indicated that {sup 226} Ra was present in the phosphate fertilizers and gypsum. The {sup 226} Ra concentrations present in these materials were between 10 {sup -4} - 10 {sup -5} {mu}g g{sup -1}. (Author).

  8. Gamma spectrometric validation of measurements test of radionuclides in food matrices; Validacao do ensaio de medidas por espectrometria gama de radionuclideos em matrizes de alimentos

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Mychelle M.L.; Custodio, Luis G.; Bonifacio, Rodrigo L.; Taddei, Maria Helena T., E-mail: mychelle@cnen.gov.br, E-mail: Igcustodio@hotmail.com, E-mail: rodrigo@cnen.gov.br, E-mail: mhtaddei@cnen.gov [Comissao Nacional de Energia Nuclear (LAPOC/CNEN-MG), de Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas

    2013-10-01

    In a testing laboratory the quality system encompasses a set of activities planned and systematic, which ensure the traceability process of an analysis, which is based on the standards NBR ISO/TEC 17025. With the need for analysis of radionuclides in food products to meet the requirements of import and export, accreditation of testing on this standard becomes increasingly necessary. The Gamma Spectrometry is a technique used for direct determination of radionuclides in different matrices, among them the food, being possible the simultaneous determination of different radionuclides in the same sample without the need for a chemical separation. In the process of Accreditation the methodology validation is an important step that includes testing accuracy, traceability, linearity and recovery. This paper describes the procedures used to validate the assay for determining radionuclides using gamma spectrometry in food. These procedures were performed through analysis of a certificated reference material by the International Atomic Energy Agency (IAEA Soil 327), analysis of samples of milk powder prepared from the doping with certified liquid standards also by the results obtained in the participation of tests of proficiency in analysis of environmental samples. (author)

  9. Test and validation of the iterative code for the neutrons spectrometry and dosimetry: NSDUAZ; Prueba y validacion del codigo iterativo para la espectrometria y dosimetria de neutrones: NSDUAZ

    Energy Technology Data Exchange (ETDEWEB)

    Reyes H, A.; Ortiz R, J. M.; Reyes A, A.; Castaneda M, R.; Solis S, L. O.; Vega C, H. R., E-mail: alfredo_reyesh@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Ingenieria Electrica, Av. Lopez Velarde 801, Col. Centro, 98000 Zacatecas (Mexico)

    2014-08-15

    In this work was realized the test and validation of an iterative code for neutronic spectrometry known as Neutron Spectrometry and Dosimetry of the Universidad Autonoma de Zacatecas (NSDUAZ). This code was designed in a user graph interface, friendly and intuitive in the environment programming of LabVIEW using the iterative algorithm known as SPUNIT. The main characteristics of the program are: the automatic selection of the initial spectrum starting from the neutrons spectra catalog compiled by the International Atomic Energy Agency, the possibility to generate a report in HTML format that shows in graph and numeric way the neutrons flowing and calculates the ambient dose equivalent with base to this. To prove the designed code, the count rates of a spectrometer system of Bonner spheres were used with a detector of {sup 6}LiI(Eu) with 7 polyethylene spheres with diameter of 0, 2, 3, 5, 8, 10 and 12. The count rates measured with two neutron sources: {sup 252}Cf and {sup 239}PuBe were used to validate the code, the obtained results were compared against those obtained using the BUNKIUT code. We find that the reconstructed spectra present an error that is inside the limit reported in the literature that oscillates around 15%. Therefore, it was concluded that the designed code presents similar results to those techniques used at the present time. (Author)

  10. Low-energy X-ray and gamma spectrometry using silicon photodiodes; Espectrometria de raios X e gama de baixa energia utilizando fotodiodos de silicio

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Iran Jose Oliveira da

    2000-08-01

    The use of semiconductor detectors for radiation detection has increased in recent years due to advantages they present in comparison to other types of detectors. As the working principle of commercially available photodiodes is similar to the semiconductor detector, this study was carried out to evaluate the use of Si photodiodes for low energy x-ray and gamma spectrometry. The photodiodes investigated were SFH-205, SFH-206, BPW-34 and XRA-50 which have the following characteristics: active area of 0,07 cm{sup 2} and 0,25 cm{sup 2}, thickness of the depletion ranging from 100 to 200 {mu}m and junction capacitance of 72 pF. The photodiode was polarized with a reverse bias and connected to a charge sensitive pre-amplifier, followed by a amplifier and multichannel pulse analyzer. Standard radiation source used in this experiment were {sup 241} Am, {sup 109} Cd, {sup 57} Co and {sup 133} Ba. The X-ray fluorescence of lead and silver were also measured through K- and L-lines. All the measurements were made with the photodiodes at room temperature.The results show that the responses of the photodiodes very linear by the x-ray energy and that the energy resolution in FWHM varied between 1.9 keV and 4.4 keV for peaks corresponding to 11.9 keV to 59 keV. The BPW-34 showed the best energy resolution and the lower dark current. The full-energy peak efficiency was also determined and it was observed that the peak efficiency decreases rapidly above 50 keV. The resolution and efficiency are similar to the values obtained with other semiconductor detectors, evidencing that the photodiodes used in that study can be used as a good performance detector for low energy X-ray and gamma spectrometry. (author)

  11. IDENTIFICAÇÃO DE COMPOSTOS ORGÂNICOS EM LIXIVIADO DE ATERRO SANITÁRIO MUNICIPAL POR CROMATOGRAFIA GASOSA ACOPLADA A ESPECTROMETRIA DE MASSAS

    Directory of Open Access Journals (Sweden)

    Eliane Sloboda Rigobello

    2015-07-01

    Full Text Available The organic compounds present in leachate can contaminate soil, superficial and underground water, and the majority is considered harmful to the environment and human health. The objective of this study was to identify organic compounds present in landfill leachate located in Maringá-PR by gas chromatography coupled to mass spectrometry (GC-MS. The raw leachate was characterized by measurements of pH, Chemical Oxygen Demand (COD, Biochemical Oxygen Demand (BOQ, Dissolved Organic Carbon (DOC, apparent and true colors, turbidity and absorbance at 254 nm. The extraction of organic compounds in leachate was carried out by liquid-liquid extraction (LLE with ethyl acetate and dichloromethane solvents, while varying the pH and ionic strength. The analysis of the leachate by GC-MS showed the presence of compounds considered to have toxic effects on the environment and human health, such as pesticides and phenolic compounds. Several compounds containing oxygenated groups such as carboxylic acids and alcohols were also identified, indicating that it was highly probable that the decomposition of waste in the landfill was in the acidogenic phase.

  12. Determination of the composition of a mixture of polar substances by NMR; Determinacao da composicao de uma mistura de substancias polares por espectrometria de ressonancia magnetica nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Antonio C.F.; Silva, Antonio J.R. da [Universidade Federal, Rio de Janeiro (Brazil). Nucleo de Pesquisas de Produtos Naturais

    1994-12-31

    This work describes the process of analysis of a mixture of polar compounds obtained from the extract of Phyllanthus tennellus, a plant known in Brazil as `quebra-pedra`, which is extensively used in Brazilian popular medicine. The methodology, which includes the use of chromatography and NMR, is described. The proposed composition of the mixture is presented. A discussion is presented concerning one component which could not be identified

  13. Spectrometry and dosimetry of isotopic sources of neutrons by means of artificial neural networks; Espectrometria y dosimetria de fuentes isotopicas de neutrones mediante redes neuronales artificiales

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R.; Ortiz R, J. M.; Hernandez D, V. M; Martinez B, M. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Gallego, E.; Lorente, A. [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, C/Jose Gutierrez Abascal No. 2, 28006 Madrid (Spain); Barquero, R., E-mail: fermineutron@yahoo.co [Hospital del Rio Hortega, C/Dulzaina No. 2, 47012 Valladolid (Spain)

    2010-09-15

    The artificial neural networks technology has been applied to reconstruct the neutrons spectra of two isotopic sources: {sup 252}Cf, and {sup 241}Am-Be. Also, this technology has been applied to obtain the effective dose, E, and the personal dose equivalents, Hp(10) and environmental, H *(10). To obtain the spectra and the doses only were used the count rates produced in a Bonner Spheres spectrometer with a scintillator of {sup 6}LiI(Eu) of 0.4 {phi} x 0.4 cm{sup 2}. The equivalent environmental dose and the spectra of the sources were also obtained by means of the reconstruction code BUNKIUT. When comparing the results obtained by means of both procedures it was found that they are consistent. (Author)

  14. Committed effective dose determination in cereal flours by gamma-ray spectrometry; Determinacao das doses efetivas por ingestao de farinhas de cereais atraves da espectrometria de raios gama

    Energy Technology Data Exchange (ETDEWEB)

    Scheibel, Viviane

    2006-07-01

    The health impact from radionuclides ingestion of foodstuffs was evaluated by the committed effective doses determined in commercial samples of South-Brazilian cereal flours (soy, wheat, corn, manioc, rye, oat, barley and rice flour). The radioactivity traces of {sup 228}Th, {sup 228}Ra, {sup 226}Ra, {sup 40}K, {sup 7}Be and {sup 137}Cs were measured by gamma-ray spectrometry employing a 66% relative efficiency HPGe detector. The energy resolution for the 1332.46 keV line of {sup 60}Co was 2.03 keV. The committed effective doses were calculated with the activities analyzed in the present flour samples, the foodstuff rates of consumption (Brazilian Institute of Geography and Statistics) and the ingestion dose coefficients (International Commission of Radiological Protection). The reliability median activities were verified with {chi}{sup 2} tests, assuring the fittings quality. The highest concentration levels of {sup 228}Th and {sup 40}K were 3.5 {+-} 0.4 and 1469 {+-} 17 Bq.kg{sup -1} for soy flour, respectively, with 95% of confidence level. The lower limit of detection for {sup 137}Cs ranged from 0.04 to 0.4 Bq.kg{sup -1}. The highest committed effective dose was 0.36 {mu}Sv.y{sup -1} for {sup 228}Ra in manioc flour (adults). All committed effective doses determined at the present work were lower than the UNSCEAR limits of 140 {mu}Sv.y{sup -1} and much lower than the ICRP (1991) limits of 1 mSv.y{sup -1}, for general public. There are few literature references for natural and artificial radionuclides in foodstuffs and mainly for committed effective doses. This work brings the barley flour data, which is not present at the literature and {sup 7}Be data which is not encountered in foodstuffs at the literature, besides all the other flours data information about activities and committed effective doses. (author)

  15. Concentration of Radon Progeny in Air by Alpha Spectrometry Measurement; Medida de los descendientes del radon en aire por Espectrometria Alfa

    Energy Technology Data Exchange (ETDEWEB)

    Acena, M L; Crespo, M T

    1989-07-01

    The concentration of radon progeny in air has been determined by alpha spectrometry measurement of 214 Po and 318 Po. A known volume of air was passed through a filter, then the alpha activity was directly measured on this filter. (Author) 15 refs.

  16. X-Ray Fluorescence Spectrometry. I.- Determination of thorium in ores; Espectrometria de fluorescencia de rayos X. A.- Aplicacion a la determinacion de torio en minerales

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez Polonio, J; Crus Castillo, F. de la; Fernandez Cellini, R

    1961-07-01

    A X-ray spectrometric method has been developed for analysis of thorium in ores in the range of concentration from 0.01 to 0.5 percent ThO{sub 2}, using selenium as a internal standard. The concentration of thorium is determined in a working curve prepared by plotting the percentage of ThO{sub 2} against the ratio intensity of the Th L{alpha}{sub 1} line to Sek{sub {beta}}1 line. (Author) 17 refs.

  17. Thallium Analysis in Environmental Samples by Inductively Coupled Plasma Mass Spectrometry; Analisis de Talio en Muestras Ambientales por Espectrometria de Masas con Fuente de Plasma de Acoplamiento Inductivo

    Energy Technology Data Exchange (ETDEWEB)

    Higueras, I; Fernandez, M; Conde, E; Gajate, A

    2008-08-06

    Due to its high toxicity, thallium has been considered by the US Environmental Protection Agency as one of the priority pollutants to be controlled. While being a highly toxic element, thallium has been studied to a much lesser degree than other toxic elements, mainly because thallium is often undetected by classical analytical methods. Thallium is a rare and dispersed element that occurs mainly in sulfur-containing ores. Thus, it is a potential pollutant to surrounding environment, if Tl-rich mineral and/or their industrial wastes are not properly disposed. In this work an Inductively Coupled Plasma Mass Spectrometry analytical procedure has been developed in order to determine thallium in environmental solid samples and its application to the study of this element as a potential pollutant associated with natural and anthropogenic activities. The analytical procedure has been validated by the use of appropriate reference materials, and through the isotope dilution technique as a primary method of measurement. Finally, the developed procedure has been applied to several samples from a mining area, as one of the scenarios where thallium it is likely to occur. (Author) 87 refs.

  18. {sup 14} C dating by using mass spectrometry with particle accelerator; Datacao por {sup 14} C utilizando espectrometria de massa com acelerador de particulas

    Energy Technology Data Exchange (ETDEWEB)

    Santos, G.M.; Gomes, P.R.S. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Fisica]. E-mail: paulogom@if.uff.br; Yokoyama, Y. [Australian National Univ., Canberra (Australia). Research School of Earth Science; Tada, M.L. di; Cresswell, R.G.; Fifield, L.K. [Australian National Univ., Canberra (Australia). Dept. of Nuclear Physics

    1999-03-01

    The different aspects concerning the {sup 14} C dating are described, including the cosmogenic origin of {sup 14} C, its production and absorption by matter, the procedures to be followed for the age determination and the associated errors, particularly by the Accelerator Mass Spectrometry (AMS) technique, and the different steps of the sample preparation process. (author)

  19. Methodology for unconditional declassification of waste materials by gamma spectrometry; Metodologia para la desclasificacion incondicional de materiales residuales mediante espectrometria gamma

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Gomez, M. A.; Gonzalez Gandal, R.; Socorro Garcia, G.; Garcia Acosta, F.

    2013-07-01

    This paper aims to present the methodology for conventional materials management through its declassification and can be used by all Spanish nuclear power plants. The methodology is based on management through declassification unconditional, ie, there are no restrictions on the origin, type of material and the final destination. (Author)

  20. Development of a methodology for radionuclide impurity analysis in radiopharmaceuticals using gamma spectrometry; Desenvolvimento de uma metodologia para analise de impurezas radionuclidicas em radiofarmacos por espectrometria gama

    Energy Technology Data Exchange (ETDEWEB)

    Paula, Eduardo Bonfim de; Araujo, Miriam Taina Ferreira de; Delgado, Jose Ubiratan; Poledna, Roberto; Lins, Ronaldo; Leiras, Anderson; Silva, Carlos Jose da; Oliveira, Antonio Eduardo de, E-mail: bonfim@bolsista.ird.gov.br, E-mail: miriamtaina@hotmail.com [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2016-07-01

    The LNMRI has sought to develop a methodology for the identification and accurate detection of gamma radiation impurities stations in metrological level, aiming to meet the recommendations not only of international pharmacopoeia, as well as the CNEN and ANVISA regarding the quality control can ensure patients the doses received by the practices are as low as feasible. As an initial target, it was possible to obtain an efficiency curve with uncertainty around 1% necessary to initiate future measurements of interest applied to nuclear medicine and to start the development of impurities analysis technique. (author)

  1. Methodology for determination of activity of radionuclides by gamma spectrometry; Metodologia para determinacao da atividade de radionuclideos por sistema de espectrometria gama

    Energy Technology Data Exchange (ETDEWEB)

    Fragoso, Maria da Conceicao de Farias; Oliveira, Victor Rogerio S. de; Oliveira, Mercia L.; Lima, Fernando Roberto de Andrade, E-mail: mariacc05@gmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-NE), Recife, PE (Brazil)

    2014-07-01

    Due to the growth in the number of procedures that make use of the positron emission tomography (PET), there is a need for standard solutions for the calibration of the systems used for the measurement of the PET radiopharmaceutical (activimeter) in radiopharmacies and in nuclear medicine services. Among the existing alternatives for the standardization of radioactive sources, the method known as gamma spectrometry is widely used for short-lived radionuclides. The purpose of this study was to implement the methodology for standardization of the {sup 18}F solutions by gamma spectrometry at the Regional Center for Nuclear Sciences of the Northeast (CRCN-NE/CNEN-NE), Brazil. (author)

  2. Factors affecting the energy resolution in alpha particle spectrometry with silicon diodes; Fatores que influenciam a resolucao em energia na espectrometria de particulas alfa com diodos de Si

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Fabio de. E-mail: f.camargo@bol.com.br

    2005-07-01

    In this work are presented the studies about the response of a multi-structure guard rings silicon diode for detection and spectrometry of alpha particles. This ion-implanted diode (Al/p{sup +}/n/n{sup +}/Al) was processed out of 300 {mu}m thick, n type substrate with a resistivity of 3 k{omega}{center_dot}cm and an active area of 4 mm{sup 2}. In order to use this diode as a detector, the bias voltage was applied on the n{sup +} side, the first guard ring was grounded and the electrical signals were readout from the p{sup +} side. These signals were directly sent to a tailor made preamplifier, based on the hybrid circuit A250 (Amptek), followed by a conventional nuclear electronic. The results obtained with this system for the direct detection of alpha particles from {sup 241}Am showed an excellent response stability with a high detection efficiency ({approx_equal} 100 %). The performance of this diode for alpha particle spectrometry was studied and it was prioritized the influence of the polarization voltage, the electronic noise, the temperature and the source-diode distance on the energy resolution. The results showed that the major contribution for the deterioration of this parameter is due to the diode dead layer thickness (1 {mu}m). However, even at room temperature, the energy resolution (FWHM = 18.8 keV) measured for the 5485.6 MeV alpha particles ({sup 241}Am) is comparable to those obtained with ordinary silicon barrier detectors frequently used for these particles spectrometry. (author)

  3. Neutron Spectrometry Work at the CNEN; La spectrometrie neutronique au CNEN; Raboty po nejtronnoj spektrometrii v nkyaeh; Trabajos de espectrometria neutronica realizados en el CNEN

    Energy Technology Data Exchange (ETDEWEB)

    Caglioti, G; Ascarelli, P [Comitato Nazionale per L' energia Nucleare Euratom, G. C. R. Ispra, Varese (Italy)

    1963-01-15

    In this communication the main features of the triple axis spectrometer recently installed at the Ispra-1 reactor are presented. Preliminary results in the quasi elastic angular distribution of 1.4A neutrons scattered in liquid bromine are shown and briefly discussed. (author) [French] Dans ce memoire, l'auteur decrit les principales caracteristiques du spectrometre triaxial installe recemment au reacteur Ispra-1. Il donne et examine brievement les resultats preliminaires des experiences sur la distribution angulaire quasi elastique de neutrons de 1.4A a diffuses dans du brome liquide. (author) [Spanish] La memoria describe las principales caracteristicas del espectrometro triaxial recientemente instalado en el reactor lspra-1. Asimismo, expone brevemente los resultados iniciales de las determinaciones de distribucion angular de neutrones de 1,4 A dispersados en forma cuasi elastica por bromo liquido. (author)

  4. Self-attenuation correction in the environmental sample gamma spectrometry; Correcao de auto-absorcao na espectrometria gama de amostras ambientais

    Energy Technology Data Exchange (ETDEWEB)

    Venturini, Luzia; Nisti, Marcelo B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1997-10-01

    Self-attenuation corrections were calculated for gamma ray spectrometry of environmental samples with densities from 0.42 g/ml up to 1.59 g/ml, measured in Marinelli beakers and polyethylene flasks. These corrections are to be used when the counting efficiency is calculated for water measured in the same geometry. The model of Debertin for Marinelli beaker, numerical integration and experimental linear attenuation coefficients were used. (author). 3 refs., 4 figs., 6 tabs.

  5. X-Ray Fluorescence Spectrometry. II Determination of Uranium in ores; Espectrometria de fluorescencia de Rayos X. II-Aplicacion a la determinacion de uranio en minerales

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez Polonio, J; Crus Castillo, F. de la; Fernandez Cellini, R

    1961-07-01

    A method of analysis of uranium in ores by X-ray spectrometry was developed, using the internal standard technique. Strontium was found to be the most suitable internal standard for general use. A Norelco Philips X-ray fluorescent spectrometer was used in this work, equipped with a lithium fluoride crystal acting as a diffraction grating analyzer. The intensity of the uranium-L {alpha}{sub 1} spectral line is calculated and related to corresponding strontium-K{sub {alpha}} spectral line, both detected with a Scintillation Counter. (Author) 31 refs.

  6. Source Hierarchy List. Volume 1. A through D

    Science.gov (United States)

    1994-07-01

    AVEIRO ’JNIV (PORTUGAL) 426929 01 AVEIRO UNIV (PORTUGAL) DEPT DE ENGENHARIA * 01 AVEIRO UNIV (PORTUGAL...INSTITUTO DE QUIMICA 01 CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS BARCELONA (SPAIN) INSTITUTO DE QUIMICA ORGANICA 01 CONSEJO SUPERIOR DE...SPAIN) INSTITUTO DE QUIMICA FISICA 01 CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS MADRID (SPAIN) INST DE OPTICA* 1377 423244 406350 094990

  7. 75 FR 62100 - Purified Carboxymethylcellulose From Mexico: Final Results of Antidumping Duty Administrative Review

    Science.gov (United States)

    2010-10-07

    ... 15, 2010) (Preliminary Results). The review covers one producer/exporter, Quimica Amtex, S.A. de C.V... Carboxymethylcellulose from Mexico: Final Determination Analysis Memorandum for Quimica Amtex, S.A. de C.V.,'' dated... June 30, 2009, is as follows: Weighted- average Producer/exporter margin (percentage) Quimica Amtex, S...

  8. Synthesis of Chromophores for Nonlinear Optics Applications

    Science.gov (United States)

    2010-03-12

    Investigacion de Quimica Aplicada Blvd. Enrique reyna, No. 140 Saltillo, Coahuila, Mexico 25253 AFOSR FA9550-09-1-0017 12 March 2010...PERFORMING ORGANIZATION REPORT NUMBER CENTRO DE INVESTIGACION EN QUIMICA APLICADA BLVD ENRIQUE REYNA NO 140 SALTILLO 25253 MEXICO...APPLICATIONS Eduardo Arias, Ivana Moggio and Ronald F. Ziolo Centro de Investigacion de Quimica Aplicada Saltillo, Coahuila, Mexico 25253

  9. 75 FR 60084 - Purified Carboxymethylcellulose from Mexico: Preliminary Results of the First Five-year (“Sunset...

    Science.gov (United States)

    2010-09-29

    ..., Quimica Amtex S.A. de C.V. (Quimica Amtex), within the 30-day deadline specified in 19 CFR 351.218(d)(3)(i... of dumping at the following weighted-average margins: Quimica Amtex 12.61 percent All Others 12.61...

  10. Chemical characterization of Xanthan biopolymers synthesized by Xanthomonas campestris pv pruni strains; Caracterizacao quimica de biopolimeros sintetizados por Xanthomonas campestris pv pruni

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Angelita da S.; Vendruscolo, Claire T.; Furlan, Ligia [Universidade Federal de Pelotas, RS (Brazil). Centro de Biotecnologia]. E-mail: angelita@ufpel.tche.br; claire@ufpel.tche.br; ligia@ufpel.tche.br; Galland, Griselda [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Qumica

    2001-07-01

    In this work we describe the characterisation of Xanthan biopolymers synthesized by two Xanthomonas campestris pv pruni strains, in aerobic fermentation. By chromatography on TLC we could notice the presence of Mannose monomer in higher proportion in the 82 strain with relation to the another ones. The viscosity results showed the temperature dependence. The 06 and 82 strains had their viscosity increased whereas for the 87 strain we could observe a reduction with temperature increasing. The {sup 13}C NMR spectrum of 87 strain showed the characteristic signals at approximately 92.8, 70.4 and 61.4 ppm, attributed to C1, C4 and C6 from glucose monomer, with higher intensity. (author)

  11. Physicochemical characterization of ceramics from Sao Paulo II archaeological site; Caracterizacao fisico-quimica da ceramica do sitio arqueologico Sao Paulo II

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Rogerio Baria

    2013-08-01

    Archaeometry is a consolidated field with a wide application of nuclear analytical techniques for the characterization, protection, and restoration of archaeological pieces. This project aimed at studying the elementary chemical composition of 70 ceramic fragments samples from Sao Paulo II archaeological site, located along the Solimoes River channel, next to Coari city, in Brazilian Amazon. The characterization of samples was performed by neutron activation analysis (NAA). By the determination of 24 elements in the ceramic fragments ( Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Sb, Sm. Rb, Se, Ta, Tb, Th, U, Yb and Zn), it was possible to define groups of samples regarding the similarity/dissimilarity in elementary chemical composition. For such a task, the multivariate statistical methods employed were cluster analysis (C A), principal component analysis (PCA) and discriminant analysis (DA). Afterwards, seven ceramic fragments were selected based on the groups previously established, for the characterization of the site temporal horizon. Those ceramic fragments were analyzed by thermoluminescence (TL) and EPR for dating purposes. The firing temperatures were determined by electron paramagnetic resonance (EPR) technique, in order to infer about some aspects of the ceramic manufacture employed by the ancient peoples that lived in Sao Paulo 11. By the results obtained in this study, it was possible to identify the quantity of clay sources employed by the ceramists and the age of the ceramic pieces. Therefore, the results of this research may contribute to the study on the occupation dynamics in the pre-colonial Brazilian Amazon. (author)

  12. Efeito da composição quimica, origem e grau de maturação sobre cor e acrocanica da banana nanica obtida por secagem HTST.

    OpenAIRE

    Michelle Oliveira

    2007-01-01

    Resumo: A banana crocante, para ser consumida na forma de snacks, pode ser obtida através de secagem com ar a altas temperaturas por um curto período de tempo (HTST - High Temperature Short Time) na fase inicial de secagem, seguida da secagem à temperatura média (50-70°C). O objetivo deste trabalho foi avaliar a influência da composição química da banana nanica (Musa acuminata Colla subgrupo Cavendish), proveniente de duas origens e três graus de maturação sobre as características de crocânci...

  13. Uncertainty analysis in the determination of absorbed dose in water by Fricke chemical dosimetry; Analise das incertezas na determinacao da dose absorvida na agua por dosimetria quimica Fricke

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, Fabia; Aguirre, Eder Aguirre, E-mail: fabiavasco@hotmail.com, E-mail: ederuni01@gmail.com [Fundacao do Cancer, Rio de Janeiro, RJ (Brazil); Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

    2016-07-01

    This work studies the calculations of uncertainties and the level of confidence that involves the process for obtaining the dose absorbed in water using the method of Fricke dosimetry, developed at Laboratorio de Ciencias Radiologicas (LCR). Measurements of absorbance of samples Fricke, irradiated and non-irradiated is going to use in order to calculate the respective sensitivity coefficients, along with the expressions of the calculation of Fricke dose and the absorbed dose in water. Those expressions are used for calculating the others sensitivity coefficients from the input variable. It is going to use the combined uncertainty and the expanded uncertainty, with a level of confidence of 95.45%, in order to report the uncertainties of the measurement. (author)

  14. Etymology of transition metal biomolecules as a learning aid in Biological Chemistry; A etimologia de biomoleculas com metais de transicao como auxiliar na aprendizagem de Quimica Biologica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jose A.L. da, E-mail: pcd1950@ist.utl.pt [Universidade Tecnica de Lisboa (Portugal). Instituto Superior Tecnico. Centro de Quimico Estrutural

    2013-11-01

    Numerous functional biomolecules are associated with metals, i.e. the metallobiomolecules; more specifically, some are dependent on transition metals required for several crucial biological roles. Nevertheless, their names can lead to ambiguous interpretations concerning the properties and performances of this group of biological molecules. Their etymology may be useful by providing a more perceptive insight into their features. However, etymology can lead to incongruous conclusions, requiring an especially careful approach to prevent errors. Examples illustrating these subjects shall be examined (author)

  15. Physico-chemical characterization of biodiesel from pests attacked corn oil; Caracterizacao fisico-quimica do biodiesel de oleo de milho danificado por pragas

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Fabia M.; Correa, Paulo C.; Martins, Marcio A.; Santos, Silmara B.; Damian, Amanda D. [Universidade Federal de Vicosa (UFV), MG (Brazil)], Emails: copace@ufv.br, aredes@ufv.br, syllmara@vicosa.ufv.br

    2009-07-01

    The biodiesel is a renewable energy source alternative to fossil fuels. The biodiesel synthesis can be made by many types of triglycerides transesterification, it is possible to use this biofuel in vehicles if it has the quality required from Agencia Nacional de Petroleo, Gas Natural e Biocombustiveis (ANP). Searching an application for pests attacked corn, there is feasibility technical for the biodiesel production from this corn oil. The biodiesel synthesis was made through ethyl transesterification process with alkaline catalyst using ethanol. The biodiesel physical-chemical characterization was performed using ANP methods. (author)

  16. Physical and chemical properties of pigmented oil obtained from shrimp heads; Evaluacion fisico-quimica de aceite pigmentado obtenido de la cabeza de camaron

    Energy Technology Data Exchange (ETDEWEB)

    Nunez-Gastelum, J. A.; Sanchez-Machado, D. I.; Lopez-Cervantes, J.; Paseiro-Losada, P.; Sendon, R.; Sanchez-Silva, A. T.; Costa, H. S.; Aurrekoetxea, G. P.; Angulo, I.; Soto-Valdez, H.

    2011-07-01

    In this work the proximal analysis, physicochemical characterization, fatty acid profile and astaxanthin content of pigmented oil obtained by fermentation shrimp heads are presented. Lipids are the major components in the oil (95%). The saponification number is 178.62 mg KOH/g, iodine value 139.8 cg iodine/g, and the peroxide value was not detected. Density and viscosity were 0.92 mg/ml and 64 centipoises, respectively. The highest contents of fatty acids were linoleic (C18:2n6), oleic (C18:1n9) and palmitic (C16:0). Eicosapentaenoic acid (C20:5n3, EPA) and docosahexaenoic acid (C22:6n3, DHA) account for 9% of the total. The content of astaxanthin was 2.72 mg/g dry weight. The pigmented oil is a dietary source of nutrients with high value such as astaxanthin. (Author) 45 refs.

  17. Chemical characterization of the gels produced by the diazotrophic bacteria Rhizobium tropici and Mesorhizobium sp; Caracterizacao quimica dos geis produzidos pelas bacterias diazotroficas Rhizobium tropici e Mesorhizobium sp.

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Nilson Kobori [Departamento de Engenharia e Tecnologia de Alimentos, Instituto de Biociencias, Letras e Ciencias Exatas, Universidade Estadual Paulista, Sao Jose do Rio Preto - SP (Brazil); Aranda-Selverio, Gabriel; Exposti, Diego Tadeu Degli; Silva, Maria de Lourdes Corradi da [Departamento de Fisica, Quimica e Biologia, Faculdade de Ciencias e Tecnologia, Universidade Estadual Paulista, Presidente Prudente - SP (Brazil); Lemos, Eliana Gertrudes Macedo; Campanharo, Joao Carlos [Departamento de Tecnologia, Faculdade de Ciencias Agrarias e Veterinaria, Universidade Estadual Paulista, Jaboticabal - SP (Brazil); Silveira, Joana Lea Meira [Departamento de Bioquimica e Biologia Molecular, Universidade Federal do Parana, Curitiba - PR (Brazil)

    2012-07-01

    The exopolysaccharides with characteristics of gel produced by Rhizobium tropici (EPSRT) and Mesorhizobium sp (EPSMR) are acidic heteropolysaccharide composed mainly of glucose and galactose in a molar ratio of 4:1 and 5:1 respectively, with traces of mannose ({approx} 1%). Chemical analysis showed the presence of uronic acid, pyruvate and acetyl-substituents in the structures of both polymers. Experiments of gel permeation chromatography and polyacrylamide gel electrophoresis showed that EPSRT and EPSMR are homogeneous molecules with low grade of polydispersity. The EPS were characterized using spectroscopic techniques of FT-IR, {sup 1}H and {sup 13}C-NMR. (author)

  18. Artificial intelligence applied to natural products; computer study of pimarane diterpene. Aplicacao da inteligencia artificial em quimica de produtos naturais: estudo, por computador, dos diterpenos pimaranicos

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, M N; Borges, J H.G.; Furlan, M; Gastmans, J P [UNESP, Araraquara, SP (Brazil). Dept. de Quimica Organica; Emerenciano, V de [Sao Paulo Univ., SP (Brazil). Dept. de Quimica Organica

    1989-01-01

    This paper describes the study of the sup(13)C NMR characteristic signals of naturally occurring pimarane. The analysis is performed by computer, starting from a data base which encloses about 400 diterpenes and using the PICKUPS programm. By this way it is possible to analyse substructure from one to five atoms as well as the effects of substituents on them. (author).

  19. Influence of chemical composition in crystallographic texture Fe-Cr-Mo alloys; Influencia da composicao quimica na textura cristalografica de ligas Fe-Cr-Mo

    Energy Technology Data Exchange (ETDEWEB)

    Moura, L.B.; Guimaraes, R.F. [Instituto Federal de Educacao, Ciencia e Tecnologia do Ceara, Fortaleza, CE (Brazil). Dept. da Industria; Abreu, H.F.G. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil)

    2010-07-01

    The use of steels with higher contents of Mo in the oil industry has been an alternative to reduce the effect of naphthenic corrosion in refining units. The addition of Mo in Fe-Cr alloys in the same manner that increases resistance to corrosion naphthenic causes some difficulties such as difficulty of forming, welding and embrittlement. In this work, experimental ingots of Fe-Cr-Mo alloys (Cr - 9, 15 and 17%, Mo - 5, 7 and 9%) were melted in vacuum induction furnace and hot and cold rolled in a laboratory rolling mill. The influence of chemical composition on crystallographic texture of samples subjected to the same thermo-mechanical treatment was analyzed by x-ray diffraction. The results indicate that fiber (111) becomes more intense with increasing Mo and/or Cr contents. (author)

  20. Influence of the mineralogical composition of cement in the diffusion of chemical species; Influencia de la composicion mineralogica del cemento en la difusion de especies quimicas

    Energy Technology Data Exchange (ETDEWEB)

    Galicia A, E.

    2015-07-01

    The disposal is the final stage of radioactive waste management. This is essentially placing them in a facility with a reasonable assurance of safety. In this last stage, the ultimate goal is the confinement and isolation of radioactive waste from the human environment for a time period and under conditions such that the release of radionuclides not put in radiation risk to people and the environment. In relation to the storage of radioactive waste of low and medium activity, the final repositories for radioactive waste, based in cement materials are already operating in many countries. The isolation is performed by applying natural or artificial barriers between radioactive waste and man so as to prevent the release of radionuclides to the environment, until they have decreased their toxicity. The cement-based materials are involved in the different stages of the radioactive waste management since they are used for immobilization of waste in the container, container manufacturing and filling the spaces between the containers and vaults container and also as a barrier engineering and construction material in civil engineering. The concrete (cement mix + water + sand + gravel) it is one of the materials used to produce the engineered barrier system and produce containers for radioactive waste. In addition to their mechanical properties (product processing into hydraulic binder after being hydrated), their composition and solubility allow cushion the contact groundwater to ph higher (12.0 - 13.5) during considerable time scales (10{sup 14} - 10{sup 15} years) and it has an active role with the radionuclides confinement present in the radiological inventory of radioactive waste. The study of the microstructures of cement is a constant challenge for specialists working in this area, mainly due to the complex and heterogeneous mineralogical composition. Cement consists of many different phases in order to achieve specific properties such as reactivity properties, setting time, color and others. Portland cements commonly used in the construction industry, they are based primarily on the mineral phases of limestone and silica. In conventional cement admixtures the chemical reactivity depends on the ratio of tricalcium and dicalcium silicate (C{sub 3}S/C{sub 2}S), the tricalcium aluminate (C{sub 3}A) influences in the setting time and tetra calcium ferro aluminate (C{sub 4}AF) gives a different color to the cement. In this research the mineralogical composition of two commercial cements is studied and its influence on the phenomenon of radionuclides retention. For this particular concrete discs were manufactured with water, sand and two commercial cements: Tolteca Extra CPC 30-RRS and Cruz Azul CPC Type II 30-R. The solid observation techniques used for analysis of the cement paste and concrete they are: X-ray Diffraction and Scanning Electron Microscopy, as well as the nuclear analytic techniques of Moessbauer and X-ray Fluorescence. (Author)

  1. Major accidents involving dangerous chemicals and Standard Basic Self-Protection; Accidentes graves en los que intervangan sustancias quimica peligrosas y Norma Basica de Autoproteccion

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Fernandez, L.

    2011-07-01

    Nuclear and radioactive facilities and other centers, institutions and agencies engaged in activities that may lead to emergency situations, are subject to specific regulations directed to take measures to prevent and control risks at source and to act initially in emergency situations and limit the consequences, in order to protect people, property and the environment. With these premise, place the following article, which summarizes the basic guidelines in the field of major accident and self-protection, summarizing the implications of current legislation in this field. (Author)

  2. 3D simulation of the thermal and chemical plumes using open source software; Simulacion 3D de las plumas termica y quimica mediante software de codigo libre

    Energy Technology Data Exchange (ETDEWEB)

    Saenz Temino, J. L.; Lerones Martin, J.; Gonzalez Delgado, J.

    2013-07-01

    The interaction of thermal and chemical plumes in the region of the Irish Sea near the site has been simulated using a finite element model representative of the local hydrodynamic regime, concluding how the method of selected cooling, open cycle, is physically and environmentally feasible. Furthermore, tunnel lengths required for each scenario under discussion have been preliminarily defined, varying in a range from 1800 to 2300 meters for a unit (1 tunnel), 4400-6300 meters of two units (2 tunnels) and 8000 meters to three units (2 tunnels), depending on the chosen technology.

  3. Influence of chemical composition of civil construction waste in the cement paste; Influencia da composicao quimica dos residuos da construcao civil a pasta de cimento

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, G.A.; Andrade, A.C.D.; Souza, J.M.M.; Evangelista, A.C.J.; Almeida, V.C., E-mail: valeria@eq.ufrj.b [Universidade Federal do Rio de Janeiro (EQ/UFRJ), RJ (Brazil). Escola de Quimica

    2009-07-01

    The construction and demolition waste when disposed inappropriately might cause serious public health problems. Its reutilization focusing on the development of new products using simple production techniques, assuring a new product life cycle and not damaging the environment is inserted in sustainable concept. The aim of this work was identifying the characteristics of types of waste generated in a residential reform (glassy ceramic and fill dirt leftovers) verifying separately its influence on cement pastes mechanical behavior. Cement pastes + wastes were prepared in 25% and 50% proportions with an approximately 0,35 water/cement relation and, glue time determination, water absorption, resistance to compression and X-ray fluorescence assays were taken. The results indicate that the chemical composition of the waste causes changes in the behavior of cement pastes, reflecting on their resistance to compression. (author)

  4. Chemical properties of gutta-percha endodontic filling material: investigation of five commercial brands; Propriedades quimicas de cones de guta-percha: avaliacao de diferentes marcas comerciais

    Energy Technology Data Exchange (ETDEWEB)

    Silva Junior, Joao Batista A.; Paula, Regina C.M.; Feitosa, Judith P.A. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica]. E-mail: juniorquim@yahoo.com.br; rpaula@dqoi.ufc.br; judith@dqoi.ufc.br; Gurgel Filho, Eduardo; Teixeira, Fabricio B [Universidade Estadual de Campinas, Piracicaba, SP (Brazil). Faculdade de Odontologia.Dept. de Odontologia Restauradora]. E-mail: gurgeleduardo@aol.com

    2001-07-01

    Chemical composition e thermal stability of five brands of gutta-percha endodontic filling material were investigated. Samples with higher amount of organic materials possess higher thermal stability. Investigation of gutta-percha polymer extracted from the endodontic filling by IR and NMR shows that the polymer is predominantly trans-polyisoprene. The thermal stability and molar mass were similar for four brands, however the 'Tanari' brand has got lower molar mass value than the other ones. (author)

  5. Chemical variations observed in irradiated, treated with IPC and control potato tubers; Variaciones quimica observadas en tuberculos de patata irradiados, tratados con IPC y testigo

    Energy Technology Data Exchange (ETDEWEB)

    Mazon Matanzo, M P; Fernandez Gonzalez, J

    1976-07-01

    The content in soluble sugars, ascorbic acid and phenolic acids of potato tubers preserved by irradiation and IPC, during storage period of five months are studied. In the irradiated tubers, soluble sugars increased immediately after the irradiation, in relation to the control tubers reaching inferior values to those reached by the control tubers, at the end of the storage period. The content in ascorbic acid is generally kept higher in the irradiated and IPC treated tubers than in the control tubers and the content in phenolic acids increased in the irradiated and IPC treated tubers by immediate effect of this treatment. (Author) 39 refs.

  6. Relatório do Mestrado em Ensino da Fisica e de Quimica no 3º Ciclo do Ensino Básico

    OpenAIRE

    Carvalho, Paulo Jorge de Oliveira

    2014-01-01

    Relatório de estágio do Mestrado em Ensino de Física e de Química no 3.º ciclo do Ensino Básico e no Ensino Secundário apresentado à Faculdade de Ciências e Tecnologia da Universidade de Coimbra

  7. Physical chemistry characterization of soils of the Storage Center of Radioactive Wastes; Caracterizacion fisico-quimica de suelos del Centro de Almacenamiento de Desechos Radioactivos

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez T, U. O.; Fernandez R, E. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, 52140 Metepec, Estado de Mexico (Mexico); Monroy G, F.; Anguiano A, J., E-mail: uohtrejo@gmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (MX)

    2011-11-15

    Any type of waste should be confined so that it does not causes damage to the human health neither the environment and for the storage of the radioactive wastes these actions are the main priority. In the Storage Center of Radioactive Wastes the radioactive wastes generated in Mexico by non energy applications are storage of temporary way. The present study is focused in determining the physical chemistry properties of the lands of the Storage Center of Radioactive Wastes like they are: real density, ph, conductivity percentage of organic matter and percentage of humidity. With what is sought to make a characterization to verify the reaction capacity of the soils in case of a possible flight of radioactive material. The results show that there are different density variations, ph and conductivity in all the soil samples; the ph and conductivity vary with regard to the contact time between the soil and their saturation point in water, for the case of the density due to the characteristics of the same soil; for what is not possible to establish a general profile, but is necessary to know the properties of each soil type more amply. Contrary case is the content of organic matter and humidity since both are in minor proportions. (Author)

  8. Chemical, mineralogical and ceramic properties of clays from Northern Santa Catarina, Brazil; Caracterizaco fisico-quimica de argilas da regiao norte de Santa Catarina

    Energy Technology Data Exchange (ETDEWEB)

    Correia, S L; Bloot, E L; Folgueras, M.V., E-mail: sivaldo@joinville.udesc.b [Universidade do Estado de Santa Catarina (UDESC/CCT), Joinville, SC (Brazil). Centro de Ciencias Tecnologicas; Hotza, D [Universidade Federal de Santa Catarina (UFSC/EQA), Florianopolis, SC (Brazil). Dept. de Engenharia Quimica

    2009-07-01

    Clay materials crop out in the northern Santa Catarina mining district were investigated in order to assess their potential in the ceramic industry. Four different clays (A, B, C and D) were selected. Their chemical composition was obtained by Xray fluorescence and their mineralogy by X-ray diffraction, coupled with numerical rational analysis. Their thermal behaviour was studied by differential thermal analysis. Technological testing consisted in a simulation of the industrial processing performed at a laboratory scale. The test pieces were obtained by pressing and fired in the range of 850-1200 deg C. In each case their technological properties were studied. The main mineralogical phases detected were kaolinite, quartz and mica. Hematite and feldspars may be present in the clays. The clays show two groups of particle sizes almost equally frequent in the range of 1 to 60 {mu}m. The northern Santa Catarina clays are suitable for the production of bricks and earthenware in the 900- 1100 deg C range. (author)

  9. Spectral analysis of colour-quenched and chemically quenched C-14 samples; Estudio espectral de muestras de C-14 con extincion quimica y por color en centelleo liquido

    Energy Technology Data Exchange (ETDEWEB)

    Scott, P E; Grau, A

    1987-07-01

    In this paper pairs of pulse height distribution curves, of C-14 samples, colour-quenched and chemically quenched was obtained. The possibility to choose a counting window in order to obtain the counting efficiency curves, for both type of quenching was studied. (Author) 7 refs.

  10. Exergetic analysis of a gas turbine plant with chemical recuperation; Analise exergetica de uma planta de turbina a gas com recuperacao quimica

    Energy Technology Data Exchange (ETDEWEB)

    Prieto, Mario G. Sanchez; Nebra, Silvia Azucena; Gallo, Waldir L. Ribeiro [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Energia]. E-mails: 192572rg@discovery.fem.unicamp.br; sanebra@fem.unicamp.br; wgallo@fem.unicamp.br

    2000-07-01

    One of the proposals that has been more recently analyzed with growing interest in Gas Turbine cycles, with the purpose of obtaining gains in the power output and thermal efficiency, is the Chemically Recuperated Gas Turbine Cycle, (CRGT). Such systems are equipped of chemical heat recovery components in which the waste heat in the turbine exhaust is used to convert a methane-steam mixture into a hydrogen-rich fuel in a methane steam reformer. One additional aspect of these cycles that represents a potential benefit is explained by the ultra-low NO{sub x} emission levels, even less than those system which use steam injection This paper, with the aid of the concepts emanated from the Second Thermodynamic Law, is presenting an evaluation of the exergetic performance of one installation of this type. Exergetic efficiencies are evaluated according to the relation fuel-product, considering one control volume for each component of the system. (author)

  11. Effects of irradiation on the physicochemical properties of carioca beans; Efeitos da irradiacao nas propriedades fisico-quimicas do feijao carioca

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Damaris Carvalho

    2016-10-01

    The common bean is an important component in the diet of the average Brazilian person. Each harvest of beans, losses occur due to attacks of insects and rodents. One of the ways to preserve the beans, and at the same time keep its nutritional characteristics, is the use of gamma radiation. This study aimed to evaluate the effects of different doses of gamma radiation on the physical and chemical properties of the carioca variety of common beans subject to cooking of soaked and unsoaked beans. Portions of raw beans were used as control and the other was subject to ionizing radiation at doses of 1, 5 and 10 kGy. Following irradiation, a portion of the samples (control and irradiated) were soaked and the other was not, then all beans were cooked. The cooked samples were lyophilized, milled and then accommodated in pots and stored at -23 deg C temperatures. The analysis of chemical composition, determination of protein digestibility, condensed tannin and phytic acid content were performed using the milled samples. Using whole grains, were performed analysis of expansion capability and hydration, cooking time and instrumental color. Irradiation did not alter the chemical composition of soaked and unsoaked samples. The condensed tannin levels did not reduce according to increased doses. The phytic acid concentrations were reduced at the doses of 5 and 10 kGy for soaked samples, whereas for the not soaked beans, gamma irradiation did not influence the phytate content. The protein digestibility decreased on soaked samples, at doses of 1 kGy and in the other doses, the reduction was not significant. As for not soaked beans, increases in digestibility were observed at dose of 10 kGy. As the doses increased, reduction in cooking time on soaked and unsoaked beans was noted. At a dose of 10 kGy, the bean expansion capability increased. The samples' color did not change significantly, as the doses increased. Therefore, it is concluded that ionizing radiation has no effect on the chemical composition and tannin content. Irradiation influenced the phytates when applied in higher doses, but only in soaked samples, as well as mitigate protein digestibility on soaked beans. It reduces cooking time, raises bean expansion capability at a 10 kGy dose, but it does not change the bean color as doses increase. (author)

  12. Chemical and microbiological assessments of the multi mixture treated by gamma radiation; Avaliacao quimica e microbiologica da multimistura tratada por irradiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Cinthia Graciele

    2008-07-01

    In Brazil, the multi mixture have being used since the eighties as an alternative against severe infantile malnutrition of the poorest population. However, its use is still reason of controversies mainly due to: the presence of anti nutritional factors, the microbiological quality and the nutritional value. Considering the routine use of multi mixture in the region, this work aimed to evaluate samples of multi mixture were collected in the metropolitan area of the City of Belo Horizonte/MG for determining the anti nutritional factors (phytic and oxalic acids), the microbiological quality, the centesimal and mineral composition, and still the induced effect in these factors of the gamma radiation. For the analyses, the samples passed by the process of gamma irradiation at doses of: 2, 4, 6, 8 and 10 kGy and then were evaluated anti nutritional factors (phytic acid and oxalic), the microbiological quality (yeasts and molds, Salmonella, Coagulase positive Staphylococcus, Bacillus cereus, coliform to 45 deg C) to full percentage (moisture, ash, proteins, carbohydrates and lipids) and the efficiency of the method of Paramagnetic Electronic Resonance (EPR) in the detection of irradiated samples. The mineral composition of the samples was carried out by the irradiation by Neutronic Activation. The methods used were searched in literature. The obtained results suggest that the concentration of the phytic and oxalic acids can not be appropriated for the children with severe nutritional deficit and that it would be necessary additional control in their daily ingestion due to the absorption of essential minerals. In general the samples had presented acceptable microbiological quality for consumption, except by one of it. The data of the centesimal and mineral composition, in the usually recommended portions, showed lower concentration than recommended for children. Any significant alteration in phytic and oxalic acids as well as in the centesimal composition were detected after gamma irradiation. The electronic paramagnetic resonance can be detected irradiated samples. (author)

  13. Coupling between solute transport and chemical reactions models. Acoplamiento de modelos de transporte de solutos y de modelos de reacciones quimicas

    Energy Technology Data Exchange (ETDEWEB)

    Samper, J.; Ajora, C. (Instituto de Ciencias de la Tierra, CSIC, Barcerlona (Spain))

    1993-01-01

    During subsurface transport, reactive solutes are subject to a variety of hydrodynamic and chemical processes. The major hydrodynamic processes include advection and convection, dispersion and diffusion. The key chemical processes are complexation including hydrolysis and acid-base reactions, dissolution-precipitation, reduction-oxidation, adsorption and ion exchange. The combined effects of all these processes on solute transport must satisfy the principle of conservation of mass. The statement of conservation of mass for N mobile species leads to N partial differential equations. Traditional solute transport models often incorporate the effects of hydrodynamic processes rigorously but oversimplify chemical interactions among aqueous species. Sophisticated chemical equilibrium models, on the other hand, incorporate a variety of chemical processes but generally assume no-flow systems. In the past decade, coupled models accounting for complex hydrological and chemical processes, with varying degrees of sophistication, have been developed. The existing models of reactive transport employ two basic sets of equations. The transport of solutes is described by a set of partial differential equations, and the chemical processes, under the assumption of equilibrium, are described by a set of nonlinear algebraic equations. An important consideration in any approach is the choice of primary dependent variables. Most existing models cannot account for the complete set of chemical processes, cannot be easily extended to include mixed chemical equilibria and kinetics, and cannot handle practical two and three dimensional problems. The difficulties arise mainly from improper selection of the primary variables in the transport equations. (Author) 38 refs.

  14. DISEÑO DE UNA HERRAMIENTA ÚTIL PARA DETECTAR TEMPRANAMENTE ALUMNOS CON DIFICULTADES EN EL APRENDIZAJE DE CONCEPTOS DE QUIMICA

    Directory of Open Access Journals (Sweden)

    Alejandra V. Quiroga

    2013-01-01

    Full Text Available El objetivo de este trabajo fue diseñar una evaluación diagnóstica que permita detectar tempranamente a aquellos alumnos con dificultades de aprendizaje e incluirlos en distintas instancias de apoyo ofrecidas por la Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata. La evaluación diagnóstica fue construida utilizando analogías de conceptos químicos que serán estudiados en el curso de Química General e Inorgánica. El uso de analogías es ampliamente utilizado en la enseñanza de la química y juega un papel importante en el proceso de enseñanza-aprendizaje de las ciencias. Se comparó el desempeño alcanzado en la evaluación diagnóstica con el resultado del primer parcial de Química General e Inorgánica y con el resultado obtenido en el examen de ingreso. Se puede concluir que la evaluación diagnóstica diseñada sería una herramienta fundamental para seleccionar potenciales participantes para el sistema de tutorías que se lleva a cabo en la Facultad de Ciencias Agrarias y Forestales.

  15. Chemical characterization of polymeric surge arresters and insulators used in high voltage lines; Caracterizacao quimica de para-raios e isoladores utilizados em linhas de alta tensao

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira Junior, Joao B. de; Castro Junior, Joao B. de; Silva, Maria Elisa S.R. e; Freitas, Roberto F.S.; Sousa, Ricardo G. de [Lab. de Ciencia e Tecnologia de Polimeros, Dept. de Engenharia Quimica da EE.UFMG, Belo Horizonte, MG (Brazil); Souza, Breno P.G. de [CEMIG Distribuicao S/A, Belo Horizonte, MG (Brazil)], e-mail: bpgsouza@gmail.com

    2011-07-01

    In the last two decades, traditional porcelain and glass surge arresters and insulators, used in the electrical system, have been replaced by polymeric materials. For this type of application it is recommended that these devices have a high resistance to environmental stresses and impacts without suffering degradation process. Considering the environmental conditions these polymers are exposed to, when used for this purpose, studies of their chemical composition are needed. In this work, polymeric materials present in surge arresters and insulators used in electrical system were chemically characterized by Fourier Transform Infrared Spectroscopy (FTIR). FTIR analysis showed that the samples tested are made of poly(dimethylsiloxane) - PDMS (silicone) and additives such as alumina trihydrated [Al (OH)3] and calcium carbonate. (author)

  16. Evaluation of the chemical modifications in petroleum asphalt cement with the addition of polypropylene; Avaliacao das modificacoes quimicas no cimento asfaltico de petroleo com a adicao de polipropileno

    Energy Technology Data Exchange (ETDEWEB)

    Marcondes, C.P.; Sales, M.J.A.; Resck, I.S., E-mail: mjsales@unb.b [Universidade de Brasilia (LabPol/UnB), DF (Brazil). Inst. de Quimica. Lab. de Pesquisa em Polimeros; Farias, M.M.; Souza, M.V.R. [Universidade de Brasilia (UnB), DF (Brazil). Dept. de Engenharia Civil e Ambiental

    2010-07-01

    Studies show that the common distress mode in the Brazilian highway network are fatigue cracks and plastic deformation, which are associated with the type of material used in the pavement layers, structural project, excessive traffic load and weathering. To minimize these defects, research on modifiers such as polymers, added to asphalt binders have been developed to provide physical, chemical and rheological improvement. This paper investigates chemical modifications of the binders with the addition of PP by FTIR, NMR and DSC. FTIR spectra of pure and modified binder showed no differences in absorption. NMR analysis showed no strong chemical bonds between the binder and PP. DSC curve of PP showed a melting temperature of 160 deg C ({Delta}H = 94J/g) and the pure binder presented an endothermic transition between 20 and 40 deg C ({Delta}H = 2J/g). In the DSC curves of mixtures, these transitions are not significant, indicating possible interactions between asphalt binder and PP. (author)

  17. Tecnologia da destilação molecular : da modelagem matematica a obtenção de dados experimentais aplicada a produtos de quimica fina

    OpenAIRE

    Cesar Benedito Batistella

    1999-01-01

    Resumo: A industrialização de compostos de química fina requer muito esforço em sua manufatura, especialmente no estágio de purificação, devido às especificações rigorosas desta classe de produtos. A destilação convencional, entretanto, em muitos casos, não pode ser utilizada, devido à instabilidade térmica dos compostos envolvidos. Existem, por exemplo, produtos sensíveis ao calor, tais como, vitaminas A, E, K, muitos intermediários farmacêuticos, como a ranitidina, diversos cosméticos, óleo...

  18. Physical-chemistry characterization of oil and biodiesel from Crambe abyssinica Hochst; Caracterizacao fisico-quimica do oleo e do biodiesel de DE Crambe abyssinica Hochst

    Energy Technology Data Exchange (ETDEWEB)

    Jasper, Samir Paulo; Biaggioni, Marco Antonio Martin; Silva, Paulo Roberto Arbex; Seki, Andre Satoshi; Saath, Reni [Universidade Estadual Paulista (FCA/UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas], E-mail: jasper@fca.unesp.br

    2010-07-01

    Currently, the production of biodiesel in the world is growing so rapidly, this interest and demand for biodiesel promote an increase in demand for raw materials, or lipids. Biodiesel is a substitute for diesel oil obtained by transesterification, acid or base, of the lipids present in oils and fats. The Crambe abyssinica Hochst is species plant that has attracted interest of Brazilian producers due to oil content, rusticity and mechanized cultivation, mainly as a crop of winter it becomes an option for most farmers in this period. This study aimed to characterize physical-chemical oil and biodiesel from Crambe abyssinica Hochst, in accordance with Resolution n. 42 of the ANP. The analysis of fatty acids of oil crambe showed high concentration of unsaturated fatty acids, which may not be suitable for the use of biodiesel in very cold regions, where it is used pure or in mixtures with diesel in large proportions. The biodiesel produced from Crambe abyssinica Hochst be revealed within the standards established by the National Agency of Petroleum, Natural Gas and Biofuels. (author)

  19. Physical-chemical characterization of sediments from Lapa Grande de Taquaracu archaeological site, MG; Caracterizacao fisico-quimica de sedimentos do sitio arqueologico Lapa Grande de Taquaracu, MG

    Energy Technology Data Exchange (ETDEWEB)

    Tudela, Diego Renan Giclioti

    2013-07-01

    In this project the elemental concentrations of Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sc, Sm, Ta, Tb, Th, U, Yb and Zn were determined by instrumental neutron activation analysis (INAA) in 60 sediment samples from Lapa Grande de Taquaracu archaeological site, located in MG State. The samples were provided by Dr. Astolfo Gomes de Mello Araujo from the Museum of Archaeology and Ethnology, University of Sao Paulo. This site is a palaeoindian rockshelter located near Lagoa Santa karst with characteristics which could be used to test karst abandonment model during the Middle Holocene related to dry conditions. The results of elemental concentrations, interpreted by multivariate statistical analysis, showed the formation of three different compositional and well-defined groups. The variable selection study by means of Procrusts analysis was also carried out. X-ray diffraction (XRD) analyses were also performed in 8 samples to study their mineralogical composition and they showed that there are distinctions in crystalline structure between the samples of the three elemental compositional groups, being quartz, calcite, dolomite and mica the main crystalline phases present in the samples. (author)

  20. Chemical composition of spoil from bituminous coal and anthracite in Spain. Composicion quimica de los esteriles de hulla y antracita de Espana

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Canibano, J; Fernandez Valcarce, A

    1991-05-01

    The article describes the chemical composition of spoil from bituminous coal and anthracite in Spain. Chemical composition, mineralogical properties and physical and mechanical characteristics are used to determine the most suitable application for the spoil in order to solve the problem of disposal. 20 refs., 5 figs., 4 tabs.

  1. Resolution of ibuprofen: a project for an experimental organic chemistry course; Resolucao do ibuprofeno: um projeto para disciplina de quimica organica experimental

    Energy Technology Data Exchange (ETDEWEB)

    Romero, Adriano L.; Baptistella, Lucia H.B.; Coelho, Fernando; Imamura, Paulo M., E-mail: imam@iqm.unicamp.br [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica

    2012-07-01

    A practical and didactic sequence of experiments was proposed to illustrate the stereochemistry concept, optically active compounds, resolution of racemates, and use of the NMR technique, including 2D-COSY for identification of organic compounds, on a laboratory course for undergraduate students. The sequence was: extractions of racemic ibuprofen and chiral naproxen from commercial tablets; syntheses of diastereoisomeric amides reacting chiral (S)-(-)-{alpha}-methylbenzylamine with (+-)-ibuprofen; separation and determination of absolute configuration of amides by {sup 1}H NMR spectroscopy and GC analysis, and hydrolysis of amides to obtain (+)- and (-)-ibuprofen. (author)

  2. Development of method to chemical separation of gallium-67 by thermal diffusion technique; Desenvolvimento de metodo para separacao quimica de galio-67 pela tecnica de difusao termica

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Patricia de Andrade

    2012-07-01

    Radioisotopes of gallium have been studied and evaluated for medical applications since 1949. Over the past 50 years {sup 67}Ga has been widely used in the diagnosis of various diseases, including acute and chronic inflammatory lesions, bacterial or sterile and several types of tumors. In Brazil 30% of clinics that provide services for Nuclear Medicine use {sup 67}Ga citrate and the demand for 67{sup G}a at IPEN-CNEN/SP is 37 GBq (1 Ci)/week. The {sup 67}Ga presents physical half-life of 3.26 days (78 hours) and decays 100% by electron capture to stable {sup 67}Zn. Its decay includes the emission of {gamma} rays with energies of 93.3 keV (37%), 184.6 keV (20.4%), 300.2 keV (16.6%) and 888 keV (26%). In the past {sup 67}Ga was produced by the reaction {sup 68}Zn (p, 2n) {sup 67}Ga at IPEN-CNEN/SP. After irradiation, the target was dissolved in concentrated HCl and the solution percolated through a cationic resin DOWEX 50W-X8, 200-400 mesh, conditioned with 10 mol L{sup -1} HCl. Zinc, nickel and copper were eluted in 10 mol L{sup -1} HCl and {sup 67}Ga 3.5 mol L{sup -1} HCl. The final product was obtained as {sup 67}Ga citrate. This work presents a new, fast, direct and efficient method for the chemical separation of 67{sup G}a by thermal diffusion (heating of the target) combined with concentrated acetic acid extraction. Purification was performed by ion exchange chromatography. Natural zinc electrodeposition was performed on nickel/copper plates as substrate and the zinc deposits were adherent to the substrate, slightly shiny and uniform. The targets were irradiated with 26 MeV protons and integrated current of 10 {mu}A.h. After irradiation, the targets were heated at 300 deg C for 2 hours and placed in contact with concentrated acetic acid for 1 hour. The average yield of extraction of {sup 67}Ga was (72 {+-} 10)%. This solution was evaporated and the residue was taken up in 0.5 mol L{sup -1} NH{sub 4}OH. The 67{sup G}a was purified on cationic resin Dowex 50WX8 in NH{sub 4}OH medium. The {sup 67}Ga recovery was (98 {+-} 2)%. This solution was evaporated and taken up in 0.1 mol L{sup -1} HCl. The chemical purity was evaluated by ICP-OES that resulted in (2 {+-} 1) {mu}g mL{sup -1} of zinc. The concentration of iron, copper and nickel was lower than the detection limits and also than the utilization limits for {sup 67}Ga. The radionuclidic purity was greater than (99.9%). This method showed to be suitable to obtain high purity {sup 67}Ga in less aggressive chemical conditions than before. (author)

  3. Asymmetric catalysis in Brazil: development and potential for advancement of Brazilian chemical industry; Catalise assimetrica no Brasil: desenvolvimento e potencialidades para o avanco da industria quimica brasileira

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Antonio Luiz, E-mail: braga.antonio@ufsc.br [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Departamento de Quimica; Luedtke, Diogo Seibert; Schneider, Paulo Henrique [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Instituto de Quimica; Andrade, Leandro Helgueira [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Quimica; Paixao, Marcio Weber [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica

    2013-07-01

    The preparation of enantiomerically pure or enriched substances is of fundamental importance to pharmaceutical, food, agrochemical, and cosmetics industries and involves a growing market of hundreds of billions of dollars. However, most chemical processes used for their production are not environmentally friendly because in most cases, stoichiometric amounts of chiral inductors are used and substantial waste is produced. In this context, asymmetric catalysis has emerged as an efficient tool for the synthesis of enantiomerically enriched compounds using chiral catalysts. More specifically, considering the current scenario in the Brazilian chemical industry, especially that of pharmaceuticals, the immediate prospect for the use of synthetic routes developed in Brazil in an enantioselective fashion or even the discovery of new drugs is practically null. Currently, the industrial production of drugs in Brazil is primarily focused on the production of generic drugs and is basically supported by imports of intermediates from China and India. In order to change this panorama and move forward toward the gradual incorporation of genuinely Brazilian synthetic routes, strong incentive policies, especially those related to continuous funding, will be needed. These incentives could be a breakthrough once we establish several research groups working in the area of organic synthesis and on the development and application of chiral organocatalysts and ligands in asymmetric catalysis, thus contributing to boost the development of the Brazilian chemical industry. Considering these circumstances, Brazil can benefit from this opportunity because we have a wide biodiversity and a large pool of natural resources that can be used as starting materials for the production of new chiral catalysts and are creating competence in asymmetric catalysis and related areas. This may decisively contribute to the growth of chemistry in our country. (author)

  4. Synthesis of zeolites from boiler fly ash: physical, chemical and mineralogical characterization; Sintese de zeolitas a partir de cinza volante de caldeiras: caracterizacao fisica, quimica e mineralogica

    Energy Technology Data Exchange (ETDEWEB)

    Rocha Junior, C.A.F.; Santos, S.C.A.; Souza, C.A.G., E-mail: augustorocha2@gmail.com [Programa de Pos Graduacao em Engenharia Quimica (PPEQ-UFPA), Belem, PA (Brazil); Angelica, R.S.; Neves, R.F. [Programa de Pos-Graduacao em Geologia e Geoquimica, Instituto de Geociencias (PPGG-IG-UFPA), Ananindeua, PA (Brazil)

    2012-01-15

    Along the years, worldwide industrial development has causing a growing generation of residues, bringing potentials environmental problems. A study of the characteristics of these wastes, as well as the development of techniques for their use in new processes becomes indispensable for the environment preservation. The main purpose of this work is to evaluate the possible use of two important industrial residues from the Amazon region for zeolite synthesis: (a) the fly ash (particle size < 100 {mu}m) that comes from burning of mineral coal in boiler; and (b) the micro silica, a by-product of the reaction between quartz and coal in the production of metallic silicon and alloys iron-silicon.The following chemical, physical and mineralogical characterization methods were carried out: X-ray diffractometry, X-ray fluorescence, scanning electron microscopy, granulometric analysis, differential thermal and thermogravimetric analysis (DTA-TG). The analyses were carried out at the following conditions: 60, 100, 150 and 190 deg C, Na{sub 2}O/Al{sub 2}O{sub 3} molar ratio of 5 and Si/Al molar ratio ranging from 2.12 to 15, and reaction time of 24 h. The results of the fly characterization demonstrate its enormous potential as raw material for the zeolite synthesis. SiO{sub 2} and Al{sub 2}O{sub 3} represent more than 50% of its composition, mineralogical phases defined, low humidity content, low particle size (d{sub 90} < 10 {mu}m), among others. Mineralogical analyses of the synthesized products showed the formation of some zeolite types, as follow: analcime, phillipsite, sodalite, zeolite P and tobermorite. The results show that the mixture fly ash-micro silica in these reaction conditions point to a promising material for zeolite synthesis (author)

  5. Effect of chemical treatment on thermal properties of fibers from pineapple;Estudo da modificacao quimica nas fibras provenientes da coroa do abacaxi

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Rafael I.M.; Mulinari, Daniella R.; Carvalho, Kelly C.C.; Conejo, Luiza dos Santos; Voorwald, Herman J.C.; Cioffi, Maria Odila H., E-mail: rafaelimf@hotmail.co [Universidade Estadual Paulista (UNESP), Guaratingueta, SP (Brazil)

    2009-07-01

    In this work the effect of the chemical modification of natural fibres from of pineapple fibres with alkaline solution was studied. After modification the in nature and modified fibres were analyzed by XRD diffractometry and thermogravimetry with objective to evaluate influence chemical treatment in surface and in the thermal properties fibres. With the obtained results it was possible to verify an increase of 10.4 % in the crystallinity index of fibres beyond the increase around 4.5% in the degradation temperature, what it indicates an increase in the stability thermal of the fibres. (author)

  6. Chemical and radiological characterization of meals served by the COSEAS (USP-SP); Caracterizacao quimica e radiologica de refeicoes servidas pelo COSEAS/USP-SP

    Energy Technology Data Exchange (ETDEWEB)

    Favaro, Deborah Ines Teixeira [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil). Centro do Reator de Pesquisas. Lab. de Analise por Ativacao Neutronica], e-mail: defavaro@ipen.br; Chioccola, Gabriella Saitta; Bortoli, Maritsa; Cozzolino, Silvia Maria Franciscato [Universidade de Sao Paulo (USP), SP (Brazil). Faculdade de Ciencias Farmaceuticas. Lab. de Alimentos e Nutricao Experimental; Taddei, Maria Helena [Comissao Nacional de Energia Nuclear (CNEN), Pocos de Caldas, MG (Brazil). Coordenacao do Laboratrio de Pocos de Caldas (COLAB); Mazzilli, Barbara Paci [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), SP (Brazil). Div. de Radiometria Ambiental

    2009-01-15

    This study presents the results obtained for the chemical and radiological analyses of lunch meals served in the cafeteria at the University of Sao Paulo-USP (COSEAS restaurant) in Brazil, on 5 non-consecutive days. On each of the five days, the meals were collected in triplicate and then freeze-dried for analysis totalizing 15 samples. The determination of the proximate composition complied with the AOAC standardized methodologies. The content of Ca, Fe, K, Na, Se, and Zn was determined by instrumental neutron activation analysis and the method validation was performed by certified reference materials analyses. Based on the concentration data, the daily intake of each mineral was calculated (corresponding to 40% of the total daily intake) and compared to the new recommendations set by the National Research Council (USA) considering the 19-30 year-old women range group. Comparing the average values obtained in this study with the recommended values, it was possible to verify that for macronutrients and the micronutrients Fe, Se, and Zn the recommendations were followed; for Ca and K they were deficient and exceeded the recommendation value for Na. The radionuclides {sup 40}K, {sup 60}Co, {sup 137}Cs, and {sup 131}I were determined by gamma spectrometry; {sup 90}Sr by liquid scintillation and {sup 210}Po, {sup 234}U, {sup 232}Th, {sup 238}U, {sup 235}U, {sup 228}Th, {sup 230}Th, and {sup 232}Th by alpha spectrometry. All radionuclides are present in concentrations below the limits set by the Food and Agriculture Organization (FAO). (author)

  7. Creació d'una eina informàtica per a la resolució de problemes d'Enginyeria Quimica

    Directory of Open Access Journals (Sweden)

    M. Isabel Vázquez Navarro

    2008-12-01

    Full Text Available El objetivo de este proyecto es crear una aplicación en web con una amplia colección de problemas de balances de materia. La herramienta potencia que el estudiante aprenda a resolver estos problemas de forma sistemática y le proporciona un mecanismo de resolución guiado, incidiendo en la metodología y pasos a seguir. Los profesores introducen los problemas de forma interactiva y automatizada. La resolución por el estudiante sigue unos pasos guiados pero dejando la máxima capacidad de decisión al mismo. Durante la resolución el estudiante es informado de los errores cometidos y se le proporcionan ayudas.

  8. Explicaciones y argumentos de profesores de quimica en formación inicial: la construcción de criterios para su evaluación

    Directory of Open Access Journals (Sweden)

    Natalia Ospina Quintero

    2011-01-01

    Full Text Available El presente documento se deriva de una investigación didáctica (Martínez y Ospina, 2008 en la que se propuso una estrategia para enseñar termodinámica a profesores de química en formación inicial. Se pretende mostrar la construcción de los criterios de evaluación diseñados con el objetivo de determinar la incidencia de las habilidades cognitivolingüísticas (Jorba, Gómez and Prat, 2000 en el aprendizaje de conceptos asociados a procesos fisicoquímicos.

  9. Caracterización Antimicrobiana Y Fisico-Quimica De Muestras De Propoleo Proveniente De La Región Andina Colombiana

    Directory of Open Access Journals (Sweden)

    E Bastos

    2011-01-01

    Full Text Available El propóleo es un material resinoso, de origen animal, producido por las abejas a partir de diversos materiales vegetales. El objetivo de este trabajo fue caracterizar muestras de propoleo provenientes de la región  andina Colombiana respecto a su perfil antimicrobiano y físico-químico. Fueron empleados extractos etanólicos de propóleos por la técnica de disco- difusión, frente a las especies Eschericia coli, S.aureus y Candida albicans. Para la caracterización físico-química se evaluo el porcentaje de extracto seco, contenidio de cera, índice de oxidación y determinación cuantitativa de compuestos fenólicos y flavonoides. Todas las muestras presentaron actividad antibacteriana, con halos de inhibición comprendidos entre 8 y 12 mm para E. coli y entre 8,3 y  23,5 mm para S. aureus, no se observo ninguna actividad para C. albicans. Los parámetros fisico-químicos citados anteriormente presentaron una variación de 2,72 a 9,17%, 0 a 2%, 3 a 51s, 0,1 a 0,5 (p/p y 0,02 a 0,95 (p/p, respectivamente. El perfil antimicrobiano observado, relacionado al físico-químico, sugiere la necesidad de nuevos estudios para la determinación del origen botánico y geográfico de las muestras estudiadas.

  10. Explicaciones y argumentos de profesores de quimica en formación inicial: la construcción de criterios para su evaluación

    Directory of Open Access Journals (Sweden)

    Natalia Ospina Quintero

    2011-01-01

    Full Text Available El presente documento se deriva de una investigación didáctica (Martínez y Ospina, 2008 en la que se propuso una estrategia para enseñar termodinámica a profesores de química en formación inicial. Se pretende mostrar la construcción de los criterios de evaluación diseñados con el objetivo de determinar la incidencia de lashabilidades cognitivolingüísticas (Jorba, Gómez and Prat, 2000 en el aprendizaje de conceptos asociados a procesos fisicoquímicos

  11. ELABORAÇÃO E CARACTERIZAÇÃO FÍSICO-QUIMICA E SENSORIAL DE ESTRUTURADOS DE POLPA CONCENTRADA DE ABACAXI

    Directory of Open Access Journals (Sweden)

    Johnatt Alan Rocha de OLIVEIRA

    2012-01-01

    Full Text Available Este trabalho teve por objetivo estudar o procedimento de estruturação de polpa concentrada de abacaxi, empregando-se diferentes hidrocoloides e altas concentrações de polpa de abacaxi. Os hidrocoloides utilizados foram: pectina de baixa metoxilação, gelatina, ágar-ágar e alginato de sódio. Utilizou-se como processo para concentração da polpa a desidratação osmótica e a concentração por evaporação á vácuo. O fruto in natura foi submetido a análises físico-químicas e para os estruturados foram realizadas análises físico-químicas e sensoriais. Os resultados mostraram ser possível obter estruturados a partir de polpa concentrada de abacaxi, com concentrações significativas de vitamina C, proteína e fibra. Quanto à análise sensorial, os estruturados de abacaxi obtiveram elevada aceitação por parte dos possíveis compradores, apresentando índices elevados de intenção de compra, com cerca de 90% dos provadores que afirmaram que certamente ou possivelmente comprariam o produto se o encontrassem à venda.

  12. Caracterización Quimica de material particulado fraciión respirable pm 10 en la atmósfera de Rioacha la Guajira Colombia

    Directory of Open Access Journals (Sweden)

    Calos Julio Doria Argumedo

    2017-01-01

    Full Text Available Teniendo en cuenta la importancia desde el punto de vista de la contaminación ambiental, que tienen las partículas inhalables PM 10 en ambientes urbanos, y que los efectos que se puedan generar en la salud dependen de la composición química del material formado por partículas, se realizó este estudio con el objetivo de revelar la composición química de las partículas atmosféricas a través de técnicas de Espectrofotometría UV-VIS y Espectrometría de Masas con fuente de Plasma de Acoplamiento, generados principalmente por fuentes naturales y antrópicas en la ciudad de Riohacha al norte de Colombia; para ello se recolectaron 30 muestras de partículas atmosféricas por medio de filtros de cuarzo con una frecuencia mensual, durante el período de marzo a diciembre de 2014. Las PM 10 presentan una concentración promedio de 52,9 µg/m 3 y los iones solubles de mayor concentración corresponden a Na + , Cl - , Ca +2 y Mg +2 . Las diferencias entre los sitios de muestreo no fueron significativas (p> 0,6. El 70% del Ca +2 es de origen no marino, atribuyéndose al suelo y al tráfico vehicular y peatonal. Conocer la composición química del material particulado, PM 10 tiene relevancia no sólo desde el punto de vista de la química de la atmósfera, sino también sobre la calidad del aire que se respira en las ciudades.

  13. COMPOSICION QUIMICA Y CONCENTRACION DE PRECURSORES DE ACIDO RUMENICO Y VACCENICO EN FORRAJES ALTERNATIVOS PARA LA ALIMENTACION DE RUMIANTES EN ECOSISTEMAS ARIDOS

    Directory of Open Access Journals (Sweden)

    Ricardo Ortega Pérez

    2009-07-01

    Full Text Available Se determinó el valor nutrimental de alfalfa henificada (AH, dos genotipos de fríjol yorimón [IT90K-277-2 (FYG18 y Sesenteño (FYG25], un clon de pasto taiwán (PT, un cultivar local de nopal en dos presentaciones, pencas tiernas de 15 días de edad o ";;;nopalitos";;; (NT y pencas maduras (NM de 60 días de edad y germinado de semillas de maíz (GM del genotipo ASGROW 7573. Se cuantificó el contenido de materia seca (MS, proteína cruda (PC, lípidos totales (LT, cenizas (C, fibra cruda (FC y energía bruta (EB, así como la concentración de ácido linoleico (LA, ácido α-linolénico (ALA, ácidos grasos poliinsaturados (PUFA y ácidos grasos n-3. Los resultados revelan que los genotipos de frijol yorimón FYG25 y FYG18, mostraron el mayor contenido de PC. Respecto a la concentración de LT, el genotipo de yorimón FYG25 mostró la mayor cantidad seguido del FYG18 y AH. Los forrajes verdes de frijol yorimón (FYG25 y FYG18, así como el pasto Taiwán tuvieron el contenido mayor de ácido α-linolénico. Las semillas de germinado de maíz mostraron los contenidos mayores de ácido linolénico seguido del nopal tierno. Ambos ácidos grasos poliinsaturados (ALA y LA son precursores del ácido ruménico y del ácido vaccénico en rumiantes. Por lo tanto, el uso de estos forrajes verdes en la alimentación de rumiantes es una alternativa que podría modificar las proporciones de ácido grasos en la leche y la carne con el propósito de incrementar los PUFA, específicamente el ácido ruménico así como el ácido vaccénico.

  14. Chemical characterization of diets consumed in the COSEAS restaurant, by neutron activation analysis; Caracterizacao quimica de dietas consumidas no restaurante do COSEAS/USP-SP, por ativacao neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Favaro, Deborah I.T. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica]. E-mail: defavaro@ipen.br; Chioccola, Gabriella S.; Bortoli, Maritsa C.; Cozzolino, Silvia M.F. [Sao Paulo Univ., SP (Brazil). Faculdade de Ciencias Farmaceuticas. Lab. de Alimentos e Nutricao Experimental]. E-mail: gabich@usp.br

    2005-07-01

    This study presents the results of chemical characterization of meals (lunch) offered by COSEAS/USP-SP restaurant, during 5 non consecutive days. These meals were collected in triplicate, in the same way they are offered to the users, being freeze-dried and prepared for chemical analysis. In the total, 15 samples were collected. The proximate composition was determined by using the standard methodologies according to AOAC (1995). The contents of some micronutrients (Ca, Fe, K, Na, Se and Zn) were determined by instrumental neutron activation analysis. The methodology validation was performed by certified reference materials analyses: Oyster Tissue (NIST SRM 1566{sup b}), Orchard Leaves (NIST SRM 1541) and Peach Leaves (NIST SRM 1547). >From concentration results the daily intake of each micronutrient was calculated considering this meal as 40% of the total daily intake and the values were compared to the new dietary recommendations of micronutrients (Dietary Reference Intakes-DRIs, Institute of Medicine, USA), for the women in the life stage from 19 to 30 years. Comparing the average values found with the recommended values, it was verified that macronutrients and Fe, Se and Zn micronutrients reached the values set by new DRIs. For Ca and K the daily intake was inadequate and Na, exceeded the recommended value. (author)

  15. Semiquantitative and quantitative measurements for EDXRF in elemental chemical composition of pigments; Medidas semi-quantitativas e quantitativas por EDXRF em composicao quimica elementar de pigmentos

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Elizabeth Cristina Soares da

    2005-02-15

    X-Ray fluorescence technique is largely used in the characterization of art and archaeological objects for restoration and conservation, allowing a multi-elemental, simultaneous and non destructive analysis. In this work it was used a portable XRF equipment of XRF that consists of a {sup 238} Pu source ( 13,6 and 17,2 keV; 95 mCi) and a SI-PIN detector coupled to a 8 k multichannel analyser. The results were collected by a palmtop computer and later analysed in a PC, through the program AXIL-QXAS. The acquisition time for each measurement was 500 s. The measurements were accomplished in a wood sculpture (Santa Luzia image, number 164) from the collection of the Museu de Etnologia da Universidade de Sao Paulo (MAE-USP), in the following regions: (STL1) inferior side of the wood base exposed without finishing, (STL2) frontal inferior base of the pedestal (dark blue) (STL3), inferior part of the frontal dress (gold), (STL4) medium part of the dress (clear blue) (STL5) mantle (red), (STL6) back central lock of the hair in the backs (black), (STL7) right cheek (flesh-coloured) and (STL8) mantle (gold). The elements found in the STL1 region were: Al, Ca, Fe and a high concentration of Zn. In the region STL2 were found Al, C, Fe, Zn and the key element Cu. In the region STL3 - Ca, Zn and the key element Au. In the region STL4 it was found Zn and the key element Cu. In the region STL5 the key element S and Hg. In the region STL6 were found Fe, Ca, S and Hg. In the region STL 7 were found Al, Cu, Hg and Zn. In the region STL8 were found Ca, Al and Au, with high concentration. It was concluded that the possible pigments would be: STL2 and STL4 - CuCO{sub 3}. Cu(OH){sub 2} + ZnO; STL3 and STL8 - Au; STL5 - HgS, STL6 - HgS mixed with other oxides, possibly of Fe and Mn, and STL 7 - HgS + ZnO. Standard samples of wood painted with pigments of the colors white, blue, red, rose, flesh color and green were also made. Through the XRF method it was verified that the white pigment is TiO{sub 2}, the red one is SeS, rose and flesh colors are a mixture of the red and white pigment, and the blue one is CoO Al{sub 2}O{sub 3}. Through the concentrations of the elementary composition of the pigments on the wood samples it was possible to calculate the sensitivity curve of the system in order to obtain quantitative data. But there are some difficulties to perform this calibration, since the sample is infinite and the disposition of layers is not uniform. It was not found papers about pigments using portable XRF in art and archaeological objects in the Brazilian literature. (author)

  16. Mineral chemistry in inerted layers of red mud from Hydro Alunorte; Quimica-mineral das camadas inertizadas em lama vermelha da Hydro Alunorte

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, Erika Raiol; Fernandez, Oscar Jesus Choque; Costa, Josivaldo Chaves, E-mail: raiolerika@hotmail.com [Instituto Federal de Educacao, Ciencia e Tecnologia do Para (IFPA), Belem, PR (Brazil)

    2016-07-01

    In this study were carried out the mineral chemistry variations in samples of the different depths and deposition time of the red mud solids from Hydro ALUNORTE Para. Red mud samples were analyzed by X-ray diffraction and fluorescence. The predominant chemical compositions are: iron, sodium and titanium oxides, residual alumina and silica. Similar phases along the profiles layers are similar and are represented by hematite, anatase, goethite, sodalite and quartz. Sometimes occur calcite, zircon, cristobalite and gypsum. The iron percentage increases in the deeper layers as well as the residual silica and alumina decrease with depth. The titanium oxide had constant. The pH of the samples ranged from 9.9 to 11. The predominant size particles are < 74 micrometers. The study shows the possibility of working with this residue in other applicability observing its characteristics. (author)

  17. Rock analyzes that could be key in biofuel production: student expands research in Germany: Escuela de Quimica sent to posgraduate student at Leipzig University

    International Nuclear Information System (INIS)

    O'neal Coto, Katzt; Puente Urbina, Allen

    2014-01-01

    University student of posgraduate in chemistry at the Universidad de Costa Rica has done an internship at the Universitat Leipzig, Germany. All the facilities were given to analyze samples of a type of sedimentary rock known as diatomite. The Nuclear Magnetic Resonance of Xenon was used to remove the fatty acids present in vegetable oil or animal fat used in the production of biodiesel [es

  18. 7. Seminar of the IIE-IMP-ININ on technological specialities. Topic 8: Analytical Chemistry; 7. Seminario IIE-IMP-ININ sobre especialidades tecnologicas. Mesa 8: Quimica Analitica

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    With the purpose to give continuity to the exchange of experiences and to impel the development of common specialties among IIE-ININ-IMP, the VII Seminary was held in Mexico City on September 7, 1994. In the event were present 163 researchers of the three participant Institutions as well as representative persons of invited institutions. The objective of this Seminary was to relate the researchers of a common branch, with the idea that the specialists made an exchange of experiences, in order to establish cooperation routes. The event was arranged in 11 working tables, with a total of 111 papers: 43 of these papers were from IIE, 42 from IMP, 22 from ININ and 4 from invited entities. During the Seminary, the 11 working tables has sessions simultaneously, and each one of the papers were discussed at the time that possible future cooperating inter institutional actions were examined. The conclusions of the Seminary were exposed in a plenary session, in the presence of the directing boards of the three participant Institutions.

  19. Caracterización Quimica de material particulado fraciión respirable pm 10 en la atmósfera de Rioacha la Guajira Colombia

    OpenAIRE

    Calos Julio Doria Argumedo; Juan Reynerio Fagundo Castillo

    2017-01-01

    Teniendo en cuenta la importancia desde el punto de vista de la contaminación ambiental, que tienen las partículas inhalables PM 10 en ambientes urbanos, y que los efectos que se puedan generar en la salud dependen de la composición química del material formado por partículas, se realizó este estudio con el objetivo de revelar la composición química de las partículas atmosféricas a través de técnicas de Espectrofotometría UV-VIS y Espectrometría de Masas con fuente de Plasma de Acoplamiento, ...

  20. Physico-chemistry characteristics of compost from urban solid wastes in Valencia (Spain); Caracteristicas fisico-quimicas de los composts de residuos solidos urbanos de la Comunidad Valenciana

    Energy Technology Data Exchange (ETDEWEB)

    Albiach, M. R.; Canet, R.; Pomares, F.; Tarazona, F.; Chaves, C.; Ferrer, E.

    2004-07-01

    For nearly twenty years samples of MSW compost produced in the Valencia region. have been analysed in our laboratories. Their main characteristics are summarised and discussed in this article, which reveals their compliance with current regulations, but also the problems which may arise if stricter requirements are eventually applied by the European Commission. (Author)

  1. Electronic waste: chemical characterization glasses of tubes cathode rays with viability for recycling; Lixo eletronico: caracterizacao quimica dos vidros de tubos de raios catodicos com viabilidade para reciclagem

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Norma Maria O.; Morais, Crislene R. Silva, E-mail: normalimam@ig.com.br [Universidade Federal de Campina Grande (UFCG), Campina Grande, PB (Brazil). Unidade Academica de Engenharia de Materiais; Lima, Lenilde Mergia Ribeiro [Universidade Federal de Campina Grande (UATEC/UFCG), Campina Grande, PB (Brazil). Unidade Academica de Tecnologia do Desenvolvimento

    2011-07-01

    Electronic waste, or e-waste, often makes incorrect destinations, which causes serious environmental problems. The aim of this study was to analyze the X-ray fluorescence to study the recycling technology for the glass of Cathode Ray Tubes or, popularly, 'picture tubes', identified by the acronym CRT (Cathode Ray Tubes), which integrate computer monitors. It was observed that the glass screen and funnel analyzed have different chemical compositions. As the silicon oxide (SiO2), the largest component of these glasses percentage 59.89% and 48.63% respectively for the screen and funnel this oxide is responsible for forming the vitreous network. The study of recycling of computer monitors it is important, since about 45% of existing materials on a monitor are made of glass, since it is 100% recyclable and can be reused, thus reducing the amount of waste deposited in the environment. (author)

  2. Process of chemical recycling of post-consumer PET using a factorial design; Processo de reciclagem quimica do PET pos-consumo empregando o planejamento fatorial

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Carlos Eduardo de O.; Almeida, Yeda Medeiros B. de; Vinhas, Gloria M., E-mail: carlos.olacerda@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2015-07-01

    The present study investigated important variables in the depolymerization reaction of post-consumer poly (ethylene terephthalate) - PET via alkaline hydrolysis. Through this reaction is obtained terephthalic acid (PTA), a monomer, which when purified, is used for the production of PET resin. The study was based on a 2{sup 2} factorial design in which the independent variables were the concentration of NaOH solution and the reaction time, and the dependent variable was the yield of PTA obtained. The experiments that generated the best results, 100 % of yield, were obtained with the higher values of the independent variables. Statistical analysis showed that the concentration of NaOH solution is the variable that most influences in the process. The PTA obtained was analyzed by NMR ¹H technique, confirming the strong resemblance to commercial PTA obtained by petrochemical way. (author)

  3. Establishment of methodology for determination of {sup 93}Zr in radioactive wastes by Liquid Scintillation Counting (LSC) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS); Estabelecimento de metodologia para determinacao de {sup 93}Zr em rejeitos radioativos por Espectrometria de Cintilacao Liquida (LSC) e Espectrometria de Massa com Plasma Indutivamente Acoplado (ICP-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Thiago Cesar de

    2014-06-01

    The zirconium-93 is a long-lived pure β-particle-emitting radionuclide produced from {sup 235}U fission and from neutron activation of the stable isotope {sup 92}Zr and thus occurring as one of the radionuclides found in nuclear reactors. Due to its long half life, {sup 93}Zr is one of the radionuclides of interest for the performance of assessment studies of waste storage or disposal. Measurement of {sup 93}Zr is difficult owing to its trace level concentration and its low activity in nuclear wastes and further because its certified standards are not frequently available. The aim of this work was to develop a selective radiochemical separation methodology for the determination of {sup 93}Zr in nuclear waste and analyze it by Liquid Scintillation Counting (LSC) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). To set up the radiochemical separation procedure for zirconium, a tracer solution of {sup 95}Zr and its 724 keV γ-ray measurements by γ- spectrometry were used in order to follow the behavior of zirconium during the radiochemical separation. For the LSC technique a {sup 55}Fe solution, which is one of the major interfering measures zirconium, was used to verify the decontamination factor during the separation process. The efficiency detection for {sup 63}Ni was used to determination of {sup 93}Zr activity in the matrices analyzed. The limit of detection of the 0.05 Bq 1{sup −1} was obtained for {sup 63}Ni standard solutions by using a sample:cocktail ratio of 3:17 mL for Optiphase Hisafe 3 cocktail. For the ICP-MS technique a zirconium stable solution was used to verify the zirconium behavior and recovery during radiochemical separation and a solution of Ba, Co, Eu, Fe, Mn, Nb, Sr and Y was used to verify the decontamination factor during the separation process. A standard solution {sup 93}Nb as isotope for determining the {sup 93}Zr by ICP-MS was used for calibration and analysis. The detection limit of 0.039 ppb was obtained for the standard solution of zirconium. Then, the protocol was applied to low level waste (LLW) and intermediate level waste (ILW) from nuclear power plants. (author)

  4. Characterisation of gas and particle emissions from wildfires =

    Science.gov (United States)

    Vicente, Ana Margarida Proenca

    Os incendios florestais sao uma importante fonte de emissao de compostos gasosos e de aerossois. Em Portugal, onde a maioria dos incendios ocorre no norte e centro do pais, os incendios destroem todos os anos milhares de hectares, com importantes perdas em termos economicos, de vidas humanas e qualidade ambiental. As emissoes podem alterar consideravelmente a quimica da atmosfera, degradar a qualidade do ar e alterar o clima. Contudo, a informacao sobre as carateristicas das emissoes dos incendios florestais nos paises do Mediterrâneo e limitada. Tanto a nivel nacional como internacional, existe um interesse crescente na elaboracao de inventarios de emissoes e de regulamentos sobre as emissoes de carbono para a atmosfera. Do ponto de vista atmosferico da monitorizacao atmosferica, os incendios sao considerados um desafio, dada a sua variabilidade temporal e espacial, sendo de esperar um aumento da sua frequencia, dimensao e severidade, e tambem porque as estimativas de emissoes dependem das carateristicas dos biocombustiveis e da fase de combustao. O objetivo deste estudo foi quantificar e caraterizar as emissoes de gases e aerossois de alguns dos mais representativos incendios florestais que ocorreram no centro de Portugal nos veroes de 2009 e de 2010. Efetuou-se a colheita de amostras de gases e de duas fracoes de particulas (PM2.5 e PM2.5-10) nas plumas de fumo em sacos Tedlar e em filtros de quartzo acoplados a um amostrador de elevado volume, respetivamente. Os hidrocarbonetos totais (THC) e oxidos de carbono (CO e CO2) nas amostras gasosas foram analisados em instrumentos automaticos de ionizacao de chama e detetores nao dispersivos de infravermelhos, respetivamente. Para algumas amostras, foram tambem quantificados alguns compostos de carbonilo apos reamostragem do gas dos sacos Tedlar em cartuchos de silica gel revestidos com 2,4-dinitrofenilhidrazina (DNPH), seguida de analise por cromatografia liquida de alta resolucao. Nas particulas, analisou-se o

  5. International Conference (4th) on Nanostructured Materials Held in Stockholm, Sweden on 14-19 June 1998. Special Volume - Part A. Volume 12, Numbers 1-4, 1999

    Science.gov (United States)

    1998-06-19

    Investigaciones Quimicas and Dpto. Quimica Inorgänica. Centra de Investigaciones Cientificas Isla de la Cartuja. Avda. Americo Vespuccio s/n, 41092...Sevilla, Spain. 3 Dpto. de Quimica- Fisica , Universidad de Sevilla, C/Prof. Garcia Gonzalez s/n, 41012-Sevilla. Abstract—An electrochemical process has...AGGREGATES J.A. Sotelo* and G.A. Niklasson# *Dpto. de Fisica y Matematicas, Universidad Peruana Cayetano Heredia, Apto. 5045, Lima, Peru

  6. Proceedings of the International Congress (12th), Corrosion Control for Low-Cost Reliability, Held in Houston, Texas on September 19 -24, 1993. Volume 3B. Corrosion: Specific Issues

    Science.gov (United States)

    1993-09-24

    de Quimica Pura y Aplicada, Monterrey N.L., 1990. No. 47. 3.- 8. Valdez, G. Guerra, J. Sampedro, N. Rosas. CORROSION, Vol. 2, No. 3, 1991, pp. 11-15...AISI 304L AND 316L STAINLESS STEELS PREPARED BY POWDER METALLURGY. E. Otero Departamento de Ciencia de Materiales Facultad de Ciencias Quimicas ...Madrid, Spain. V. Utrilla Departamento de Ciencia de Materiales Facultad de Ciencias Quimicas Universidad Complutense 28040-Madrid, Spain. E. Sfienz

  7. Mechanisms of Laser Induced Reactions in Opaque Heterogeneous Environments

    Science.gov (United States)

    1993-11-01

    ST. Av. bonds, both within its own structure and also with Rovisco Pais. 109h Lisboa Codex. Portugal. §Present address: Centro de Quimica Pura e...and L. F. VIEIRA FERREIRA Centro de Quimica Fisica Molecular, Universidade Ttcnica de Lisboa. Complexo 1, Instituto Superior Tecnico, Av. Rovisco Pais...and Ana R. Garcia Centro de Quimica Fisica Molecular, Universidade Tecnica de Lisboa--Complexo I-IST. Av- Rovisco Pais, 1096 Lisboa Codex, Portugal

  8. International Symposium on Polymer Electrolytes (3rd) Held in Annecy, France on June 17-21, 1991. Extended Abstracts

    Science.gov (United States)

    1991-06-01

    ELECTROLYTES. J. Morgado, L. Alcicer Departamento de Engenharia Quimica , Instituto Superior T&nico P- 1096 Lisboa Codex, Portugal As previoulsy...Alcicer Departamento de Engenharia Quimica , Instituto Superior Tdcnico P-1096 Lisboa, Portugal (PEO)nZnX 2 films, in the range n=4-40 were prepared by...RARE EARTH SALTS T. M. A. Abrantes and L. Alcdcer Departamento de Engenharia Quimica , Instituto Superior Tcnico P;4096 Lisboa, Portugal L. A. Dias

  9. Cholesteric Liquid Crystal Glass Platinum Acetylides

    Science.gov (United States)

    2014-06-01

    M. Krein AFRL/RXAP Ronald F. Ziolo, Eduardo Arias, and Ivana Moggio 2Centro de Investigacion en Quimica Aplicada(CIQA) Albert Fratini... Quimica Aplicada(CIQA), Boulevard Enrique Reyna Albert Fratini - Department of Chemistry, University of Dayton Yuriy Garbovskiy and Anatoliy...Force Research Laboratory Materials and Manufacturing Directorate Wright-Patterson Air Force Base, OH 45433-7750 Centro de Investigacion en Quimica

  10. Co-Sponsorship of 1999 Conference on the Dynamics of Molecular Collision (17th) held in Lake Harmony, Pennslyvania on 18-23 July 1999.

    Science.gov (United States)

    2000-02-25

    Cambridge, Cambridge CB2 1EW, U.K. Fernando Castafio and Maria N. Sanchez Rayo Departamento de Quimica Fisica, Universidad del Pais Vasco, Apartado...Welge Fakultät für Physik. Universität Bielefeld, Germany F.J. Aoiz, L. Banares, J.F. Castillo, B. Marti’nez-Haya Departamento de Quimica Fisica...8656 Tokyo, Japan M A.J.C. Varandas • Departamento de Quimica Sangwoon Yoon Universidade de

  11. New Meta and Nanomaterials for Photorefractive Enhancement and Photorefractive Two-Beam Coupling

    Science.gov (United States)

    2010-03-12

    Centro de Investigacion de Quimica Aplicada Blvd. Enrique reyna, No. 140 Saltillo, Coahuila, Mexico 25253 AFOSR FA9550-09-1-0023 12 March 2010...ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER CENTRO DE INVESTIGACION EN QUIMICA APLICADA BLVD ENRIQUE REYNA NO 140 SALTILLO 25253...Photorefractive Two-Beam Coupling Ronald F. Ziolo Centro de Investigacion de Quimica Aplicada Saltillo, Coahuila, Mexico 25253 Grant

  12. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Author Affiliations. Prithwiraj Byabartta1 2. Department of Chemistry, University of Burdwan, Golapbag, Burdwan 713 104; Departmento de Quimica Inorganica, Universidad de Zaragoza, Zaragoza 50009, Spain ...

  13. Study on the natural radioactivity from the region of Presidente Figueiredo (AM), Brazil, using gamma spectrometry; Estudo da radioatividade natural da regiao de Presidente Figueiredo (AM) utilizando espectrometria gama

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva, Jose Ribamar Silveira

    1999-07-01

    A gamma spectrometry profile was carried out along BR174 highway, that crosses some lithostratigraphic units of the North portion of the Sedimentary Basin of Amazon. Measurements in situ were realized in 116 points, 1 km apart, using a GAD-6 gamma-spectrometer and samples of rocks and soils were collected in geologically representative points, for gamma measurements using a shielded detector of NaI(Tl) available in the Nuclear Geophysics Laboratory of IAG/USP. The criterion used for evaluating the reliability degree of the concentration values of eU (ppm), eTh (ppm) and %K was to establish mathematically detection limits, for all measurement points. Every these points had been located using GPS with accuracy of 50 m to become possible a future detailed study. The purpose of matching portable gamma spectrometer and laboratory determinations was to compare the 2 techniques, using the criterion of detectability limits, and to verify the influence of {sup 222} Rn atmospheric radioactive gas in field measurements. In the case of portable detector, it allows fast measurements and the sensor 'sees' a big volume of material (rock, soil...), that makes it more representative. In some situations where atmospheric phenomena of thermal inversion occurs, measurement can be affected by the {sup 222} Rn cosmic background. Presence of radon daughter elements, associated with aerosols, in this tropical environment (high values of temperature and humidity), where the speed of the wind that could exhaust this gas is practically zero. It is observed that the values of concentration in the some points, got with these 2 techniques, have the same trend, and the stretches where peaks of concentration of K also occur and U and Th are associated with the presence of granite out corps, great boulders, and clay soils from weathering of these rocks. (author)

  14. Neutron spectrometry and dosimetry with neural networks and Bonner spheres: a study to reduce the spheres number; Espectrometria y dosimetria neutronica con redes neuronales y esferas Bonner: un estudio para reducir el numero de esferas

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza G, J. G.; Martinez B, M. R.; Leon P, A. A.; Hernandez P, C. F.; Castaneda M, V. H.; Solis S, L. O.; Castaneda M, R.; Ortiz R, J. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Av. Ramon Lopez Velarde 801, Col. Centro, 98000 Zacatecas, Zac. (Mexico); Mendez, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Laboratorio de Patrones Neutronicos, Av. Complutense 22, 28040 Madrid (Spain); Gallego, E. [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain); De Sousa L, M. A. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, MG (Brazil)

    2016-10-15

    For neutron spectrometry and neutron dosimetry, the Bonner spheres spectrometric system has been the most widely used system, however, the number, size and weight of the spheres composing the system, as well as the need to use a reconstruction code and the long periods of time used to carry out the measurements are some of the disadvantages of this system. For the reconstruction of the spectra, different techniques such as artificial neural networks of reverse propagation have been used. The objective of this work was to reduce the number of Bonner spheres and to use counting speeds in a reverse propagation neural network, optimized by means of the robust design methodology, to reconstruct the neutron spectra. For the design of the neural network we used the neutron spectra of the IAEA and the response matrix of the Bonner spheres with {sup 6}LiI(Eu) detector. The performance of the network was compared; using 7 Bonner spheres against other cases where only 2 and one sphere are used. The network topologies were trained 36 times for each case keeping constant the objective error (1E(-3)), the training algorithm was trains cg and the robust design methodology to determine the best network architectures. With these, the best and worst results were compared. The results obtained using 7 spheres were similar to those with the 5-in sphere, however is still in an information analysis stage. (Author)

  15. Software tool for resolution of inverse problems using artificial intelligence techniques: an application in neutron spectrometry; Herramienta en software para resolucion de problemas inversos mediante tecnicas de inteligencia artificial: una aplicacion en espectrometria neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda M, V. H.; Martinez B, M. R.; Solis S, L. O.; Castaneda M, R.; Leon P, A. A.; Hernandez P, C. F.; Espinoza G, J. G.; Ortiz R, J. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, 98000 Zacatecas, Zac. (Mexico); Mendez, R. [CIEMAT, Departamento de Metrologia de Radiaciones Ionizantes, Laboratorio de Patrones Neutronicos, Av. Complutense 22, 28040 Madrid (Spain); Gallego, E. [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, C. Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Sousa L, M. A. [Comision Nacional de Energia Nuclear, Centro de Investigacion de Tecnologia Nuclear, Av. Pte. Antonio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    The Taguchi methodology has proved to be highly efficient to solve inverse problems, in which the values of some parameters of the model must be obtained from the observed data. There are intrinsic mathematical characteristics that make a problem known as inverse. Inverse problems appear in many branches of science, engineering and mathematics. To solve this type of problem, researches have used different techniques. Recently, the use of techniques based on Artificial Intelligence technology is being explored by researches. This paper presents the use of a software tool based on artificial neural networks of generalized regression in the solution of inverse problems with application in high energy physics, specifically in the solution of the problem of neutron spectrometry. To solve this problem we use a software tool developed in the Mat Lab programming environment, which employs a friendly user interface, intuitive and easy to use for the user. This computational tool solves the inverse problem involved in the reconstruction of the neutron spectrum based on measurements made with a Bonner spheres spectrometric system. Introducing this information, the neural network is able to reconstruct the neutron spectrum with high performance and generalization capability. The tool allows that the end user does not require great training or technical knowledge in development and/or use of software, so it facilitates the use of the program for the resolution of inverse problems that are in several areas of knowledge. The techniques of Artificial Intelligence present singular veracity to solve inverse problems, given the characteristics of artificial neural networks and their network topology, therefore, the tool developed has been very useful, since the results generated by the Artificial Neural Network require few time in comparison to other techniques and are correct results comparing them with the actual data of the experiment. (Author)

  16. Optimization of the architecture of a neural network in neutron spectrometry to reduce the number of Bonner spheres; Optimizacion de la arquitectura de una red neuronal en espectrometria de neutrones para reducer el numero de esferas Bonner

    Energy Technology Data Exchange (ETDEWEB)

    Leon P, A. A.; Martinez B, M. R.; Hernandez P, C. F.; Espinoza G, J. G.; Castaneda M, V. H.; Solis S, L. O.; Castaneda M, R.; Ortiz R, J. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Av. Ramon Lopez Velarde 801, Col. Centro, 98000 Zacatecas, Zac. (Mexico); Mendez V, R. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Laboratorio de Patrones Neutronicos, Av. Complutense 22, 28040 Madrid (Spain); Gallego, E. [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, ETSI Industriales, Jose Gutierrez Abascal 2, 28006 Madrid (Spain); De Sousa L, M. A. [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Av. Pte. Antonio Carlos 6627, 31270-901 Pampulha, Belo Horizonte, Minas Gerais (Brazil)

    2016-10-15

    The neutron spectrometry is an experimental process for determining the energy distribution called the Spectrum. Among the methods available for neutron spectrometry, one can mention the Bonner Sphere Spectrometric System as one of the most used, consisting of a detector placed in the center of a set of polyethylene spheres whose diameters range from 2 to 18 inches, however has some disadvantages such as the long periods of time to perform the measurements, the weight and the spheres number that vary according to the system. From this, alternative methods such as artificial neural networks are proposed. For this project neural networks of reverse propagation were used with the methodology of robust design of artificial neural networks, with the aid of a computational tool that maximizes the performance, making the time used for the training s of the network is the smallest possible and thus gets the orthogonal fixes quickly to determine the best network topology. The counting rates of a spectrometric system with 7 spheres, 2 spheres and one sphere of 5 and 8 inches were used. This methodology seeks to reduce the work used as in the spectrometric system formed by a greater number of spheres, since to enter less data in the counting rates to obtain the spectra with 60 energy levels saves time and space, because at having a smaller number of spheres its portability is easier to move from one place to another, for this we performed several experiments with different errors until we reached the optimal error so that the topology of the network was appropriate and find the best design parameters. A statistical software JMP was also used to obtain the best topologies and thus to retrain obtaining its best and worst spectra, in order to determine if the reduction is possible. (Author)

  17. Determinação de arsênio em amostras da cadeia produtiva de frangos de corte por espectrometria de absorção atômica com forno de grafite

    Directory of Open Access Journals (Sweden)

    Amália G. G Dionísio

    2011-01-01

    Full Text Available Chicken meat is largely consumed in human nutrition and it is produced in extremely large scale in some countries, including Brazil. In this work graphite furnace atomic absorption spectrometry was used for determination of arsenic in chicken and chicken production-related samples. These samples were digested employing a microwave-assisted procedure in closed vessels using a 7 mol L-1 nitric acid solution plus concentrated hydrogen peroxide. The concentration range of total As determined in chicken production-related samples varied from 1.30 to 29.8 mg kg-1 of As. The detection and quantification limits reached were 0.055 and 0.182 mg kg-1, respectively (n = 15.

  18. Dose calculation for {sup 40}K ingestion in samples of beans using spectrometry and MCNP; Calculo de dose devido a ingestao de {sup 40}K em amostras de feijao utilizando espectrometria e MCNP

    Energy Technology Data Exchange (ETDEWEB)

    Garcez, R.W.D.; Lopes, J.M.; Silva, A.X., E-mail: marqueslopez@yahoo.com.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/PEN/UFRJ), Rio de Janeiro, RJ (Brazil). Centro de Tecnologia; Domingues, A.M. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Fisica; Lima, M.A.F. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Biologia

    2014-07-01

    A method based on gamma spectroscopy and on the use of voxel phantoms to calculate dose due to ingestion of {sup 40}K contained in bean samples are presented in this work. To quantify the activity of radionuclide, HPGe detector was used and the data entered in the input file of MCNP code. The highest value of equivalent dose was 7.83 μSv.y{sup -1} in the stomach for white beans, whose activity 452.4 Bq.Kg{sup -1} was the highest of the five analyzed. The tool proved to be appropriate when you want to calculate the dose in organs due to ingestion of food. (author)

  19. Isotope Dilution - Thermal Ionisation Mass Spectrometric Analysis for Tin in a Fly Ash Material; Analisis de Estano en una Ceniza de Combustion mediante Espectrometria de Masas de Ionizacion Termica con Dilucion Isotopica

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, C; Fernandez, M; Quejido, A L

    2006-07-01

    Isotope dilution-thermal ionisation mass spectrometry (ID-TIMS) analysis has been applied to the determination of tin in a fly ash sample supplied by the EC Joint Research Centre (Ispra, Italy). The proposed procedure includes the silica gel/phosphoric acid technique for tin thermal ionisation activation and a strict heating protocol for isotope ratio measurements. Instrumental mass discrimination factor has been previously determined measuring a natural tin standard solution. Spike solutions has been prepared from 112Sn-enriched metal and quantified by reverse isotope dilution analysis. Two sample aliquots were spiked and tin was extracted with 4,5 M HCI during 25 min ultrasound exposure time. Due to the complex matrix of this fly ash material, a two-step purification stage using ion-exchange chromatography was required prior TIMS analysis. Obtained results for the two sample-spike blends (10,10 + - 0,55 y 10,50 + - 0,64 imolg-1) are comprarable, both value and uncertainty. Also a good reproducibility is observed between measurements. The proposed ID-TIMS procedure, as a primary method and due to the lack of fly ash reference material certified for tin content, can be used to validate more routine methodologies applied to tin determination in this kind of materials. (Author) 75 refs.

  20. An X-ray fluorescence method for the determination of small quantities el elements collected on filters; Determinacion de pequenas concentraciones de elementos en filtros por espectrometria de fluorescencia de rayos X

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Guerra, J. P.; Bayon, A.

    1981-07-01

    An X-ray fluorescence method for the determination of As, Ba, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, U, V and Zn collected on P.V.C. filters in concentration ranges from 0,6 to 1000{mu}g, depending on the element, is described. A sequential automatic spectrometer with a chromium tube is used for tho Ba determination, while As, Hg, Pb, Se and U are bottler determined with a molybdenum one. For the rest of the elements a tungsten target is preferred. The interferences between AsK{sup {alpha}}{sub 1},2- PbL{sup {alpha}}{sub 1},2 and CrK{sup {alpha}}{sub 1},2-Vk{beta}{sub 1},3 lines are corrected by applying specific coefficients. The radial variation of the primary X-ray beam intensity on the irradiated surface has been specially studied with chromium, gold, molybdenum and tungsten tubes. For that purpose different x-ray wavelengths in the range 9,89 A to 0,56 A have been selected. The curves obtained show a rather high heterogeneity for the excitation source. This conclusion implies the need for an homogeneous distribution of elements on the filter. (Author) 7 refs.

  1. Preliminary results of neutron spectroscopy in proton therapy treatment room in Ithemba Labs (South Africa); Resultados preliminares de espectrometria de neutrones en la sala de tratamiento de protonterapia en Ithemba Labs (Sudafrica)

    Energy Technology Data Exchange (ETDEWEB)

    Domingo, C.; Garcia-Fuste, M. J.; Amgarou, K.; Sanchez-Doblado, F.; Nieto-Camero, J.

    2011-07-01

    Proton beams originating from accelerators high energy hadrons lead to the production of neutrons when protons interact with the elements present in the beam line. Furthermore, when these protons are used for proton therapy treatments, their interaction with the patient also involves production of neutrons, mainly due to interactions with the C, O and N. This represents a source of unwanted radiation that increases the risk of developing second cancers by the patient. Assessment of risk factors is one of the goals of our project.

  2. Decision Threshold and Detection Limit in Spectrometric Measurements. Part 1: Application to Gamma Spectrometry; Umbral de Decision y Limite de Deteccion en Medidas Espectrometricas. Parte 1: Aplicacion a la Espectrometria Gamma

    Energy Technology Data Exchange (ETDEWEB)

    Perez, C.; Gasco, C.; Lopez, M.A.

    2010-03-03

    This report summarised the author's lecture of the advanced gamma spectrometry course organised by CIEMAT. The characteristic limits determination in gamma spectrometry generally is obtained through the programming that the trade marks offers to the client with the objective of the automatic calculation of the activity concentrations existing in a sample. In this report, the examples shown in the ISO 11929 standard are compared to the programming realised by Genie 2k for determining characteristic limits. The main difference of both is located in the uncertainty calculations due to the efficiency calibration that is considered by ISO and not by Genie 2K. Through implementation in the software developed by trade marks will be possible to introduce this uncertainty and to assimilate to the calculation done by ISO 11929. In the second part of this report will be analyzed the more complicated samples of this application as counting in a whole body counter (following ISO-28218 about Performance Criteria for radio bioassay), multiplet, overlapping, addition of several peaks for obtaining the activity concentration, etc. (Author) 19 refs.

  3. Assembly of positioner of automated two-dimensional scan coupled to X-ray fluorescence spectrometry; Montagem de posicionador de varredura bidimensional automatizada acoplado a espectrometria de fluorescência de raios-X

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Leonardo Santiago Melgaço

    2011-07-01

    This work describes the design and assembling of a prototype automated positioner two-dimensional scanning coupled to X-ray fluorescence spectrometry. The work aims to achieve a portable and easy to use, device of broad utility in the analysis of samples by X-ray fluorescence area of expertise and research. The two-dimensional scanning of the positioner is by means of two stepper motors controlled by a microcontroller PIC 16F877A, encoder and optical sensors. The user interacts with the XY table through an interface program for the Windows operating system, which communicates with the microcontroller through the serial port. The system of Fluorescence Spectroscopy incorporated into the positioner consists of a system commercially available system from the company AMPTEK, where the primary source of excitation of the sample was a source of {sup 241}Am of 59.5 KeV emissions. Resolution and accuracy of tests were performed in the XY scanning process and reproducibility of the same kit with the fluorescence spectrometry X-ray. Qualitative tests by X-ray fluorescence spectrometry in samples were performed to demonstrate the applicability and versatility of the project. It follows that the prototype illustrates a possible adequately to portable device for X-ray spectrometry of two-dimensional. (author)

  4. Adsorption of Hydrogen and Potassium on GaAs(110) Studied by Time-of-Flight Scattering and Recoiling Spectrometry; Espectrometria de Iones Aplicada al Estudio de la Adsorcion de H y K en GaAs(110)

    Energy Technology Data Exchange (ETDEWEB)

    Gayone, J E [Comision Nacional de Energia Atomica, Centro Atomico Bariloche (Argentina)

    2000-07-01

    We study the adsorption of H and K on a GaAs(ll0) surface by Time-of-Flight Ion-Scattering (ISS) and Direct Recoiling (DRS) Spectrometry. The method for cleaning and preparation of the surface consists on cycles of grazing bombardment with 20 keV Ar+ combined with annealing. Since this is the first time that this method is applied to a semiconductor surface, the crystallographic structure of the grazing ion bombarded surface is first characterized by ISS and DRS. The variations of the projectile scattered intensity as a function of the incident and azimuthal angles are interpreted in terms of calculated shadowing and focusing effects. The crystallographic structure of the GaAs(ll0) surface prepared by this method presents the surface relaxation observed for cleaved surfaces. The adsorption of H on GaAs(ll0) is studied as a function of the H{sub 2} exposure and the surface temperature.The behavior of the intensity of projectiles scattered from the first two As and Ga layers is consistent with a process of unrelaxation towards the ideal surface termination upon H adsorption. We have determined that for exposures of 1000 L and 2000 L the AsI-GaI splitting corresponding to the unrelaxed surface is reduced to {delta}Z = (0.0 n 0.08) A, as it should be expected for the bulk terminated surface. In addition, the fraction of the surface remaining relaxed as in the clean surface decreases strongly with the H{sub 2} exposure. The H atoms adsorbed on the surface can be detected as recoils produced in quasi-single collisions allowing the study of the adsorption kinetics. The variations of the H recoil intensity with the exposure show that the sticking coefficient changes strongly with the H coverage since the beginning the adsorption. Above {approx} 500 L, the adsorption kinetics deviates from the initial behavior and the sticking coefficient becomes almost constant and small. The simultaneous measurements of the H coverage (with DRS) and the changes in the atomic structure (with ISS) as a function of the exposure indicate that the initial strong decrease in the rate of unrelaxation is mainly a consequence of the variation of the sticking coefficient. Below 100 L, most of the H atoms participate in the unrelaxation process. However, above 500 L, it is necessary to increase strongly the H coverage to produce small changes in the atomic structure of the surface. The measurements of the As and Ga direct recoils intensities change with the incident direction of the projectile in accordance with the crystallographic structure of the surface. On the other hand, the H recoil intensity is almost independent of the crystallographic sample orientation, indicating that an important fraction of the H atoms are not adsorbed in well ordered sites.Measurements as a function of the sample temperature show a continuous decrease of the H DR intensity for both low and high exposures. The combined results of forward recoiled atom and scattered projectile intensities suggest that an important fraction of the adsorbed H atoms is not bonded in a well ordered layer and may be forming molecules since the beginning of the adsorption process. The adsorption of K on GaAs(110) is mainly studied by DRS. The analysis of K direct recoil intensity indicates that at room temperature, the adsorption of K saturates at 0.5 ML, which corresponds to an atom density of {approx} 4.4x10{sup 1}4 at/cm{sup -2}. The adsorption process proceeds in two stages, which depend on the K coverage ({theta} (K)). At low coverages, {theta} (K)<0.1 ML, the K atoms are adsorbed exclusively on the [001] Ga rows and close to the sites of a new As layer, with a local crystallographic order. At high coverages the K atoms start to adsorb also along the As rows, although with a lower probability than on the Ga rows. At saturation, the K layer does not form an ordered structure. The dependence of the direct-recoil ion fractions on the K coverage is consistent with the structural information obtained from the analysis of the total recoiled intensity (ions plus neutrals). At low cov

  5. Quantification of {sup 235} U and {sup 226} Ra in soil samples by means of Gamma spectroscopy; Cuantificacion de {sup 235} U y {sup 226} Ra en muestras de suelo por medio de espectrometria gamma

    Energy Technology Data Exchange (ETDEWEB)

    Quintero P, E.; Rojas M, V.P.; Montes M, F.R.; Gaso P, M.I.; Cervantes N, M.L. [Gerencia de Innovacion Tecnologica, A.P. 18-1027, C.P. 11801 Mexico D.F. (Mexico)

    2000-07-01

    In this work it is presented the Gamma Spectroscopy method which is realized in the Environmental Radiological Surveillance Laboratory using the option of deconvolution of a commercial software for the quantification of {sup 235} U and {sup 226} Ra; also is presented the method for the {sup 226} Ra correction activity. (Author)

  6. Determination of essential and toxic elements in commercial baby foods by instrumental neutron activation analysis and atomic absorption spectrometry; Determinacao dos elementos essenciais e toxicos em alimentos comerciais infantis por analise por ativacao com neutrons e espectrometria de absorcao atomica

    Energy Technology Data Exchange (ETDEWEB)

    Vallinoto, Priscila

    2013-08-01

    The World Health Organization recommends that infants should be breast fed exclusively for at least six months after birth. After this period, it is recommended to start introducing complementary foods, in order to meet the child's nutritional, mineral and energy needs. Commercial food products for infants form an important part of the diet for many babies. Thus, it is very important that such food contains sufficient amounts of minerals. Inadequate complementary feeding is a major cause of high rates of infant malnutrition in developing countries. In this study, essential elements: Ca, Cl, Co, Cr, Fe, K, Mg, Mn, Na, Se and Zn and toxic elements: As, Cd, Hg levels were determined in twenty seven different commercial infant food product samples by Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometry (AAS). In order to validate both methodologies the reference material: INCT MPH-2 Mixed Polish Herbs and NIST - SRM 1577b Bovine Liver by INAA and NIST - SRM 1548th Typical Diet and NIST - SRM 1547 Peach Leaves by AAS were analyzed. The twenty seven baby food samples were acquired from Sao Paulo city supermarkets and stores. Essential and toxic elements were determined. Most of the essential element concentrations obtained were lower than the World Health Organization requirements, while concentrations of toxic elements were below the tolerable upper limit. These low essential element concentrations in these samples indicate that infants should not be fed only with commercial complementary foods. (author)

  7. Determination of Th and U by neutron activation for gamma spectrometry calibration in situ; Determinacion de Th y U por activacion neutronica para calibracion de espectrometria gamma in situ

    Energy Technology Data Exchange (ETDEWEB)

    Nava M, F.; Rios M, C.; Mireles G, F.; Saucedo A, S.; Davila R, I.; Pinedo, J. L. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas (Mexico); Landsberger, S., E-mail: iqnava@hotmail.com [University of Texas at Austin, Nuclear Engineering Teaching Laboratory, Pickle Research Campus, R9000 Austin, Texas 78712 (United States)

    2012-10-15

    Using the analysis by neutron activation to determine the profile of the thorium and uranium concentration calibration factors were obtained for their use in the gamma spectrometry in situ. Three sites were selected (San Ramon, Villa de Cos y la Zacatecana) and the analysis by activation was development in the Laboratory of Nuclear Engineering Teaching of the Texas University in Austin with the nuclear reactor Ut-TRIGA. Starting from the gamma spectra in situ, the areas of normalized photo-pick of the radioisotopes were: {sup 208}Tl and {sup 228}Ac for the thorium series and {sup 214}Pb and {sup 214}Bi for the uranium series. The averages of the factors found in units of (cpm/Bq/Kg) are of 105.63{+-}8.32 and 75.87{+-}4.61 for the thorium and uranium, respectively. (Author)

  8. Análise de pesticidas organoclorados em água usando a microextração em fase sólida por headspace com cromatografia gasosa e espectrometria de massas

    Directory of Open Access Journals (Sweden)

    Crislaine Batista Prates

    2011-01-01

    Full Text Available A method based on headspace - solid phase microextraction coupled with gas chromatography - mass spectrometry was validated for the quantitative determination of 18 organochlorine pesticides in water. For the extraction conditioning some parameters as the best type of coating fiber, time and temperature of extraction, pH and ionic strength were evaluated. The method HS-SPME/GC-MS/MS showed linear coefficient above 0.9948. The repeatability of the measurements were lower than 7.6%. Relative recoveries were between 88 and 110%. Limits of detection from 0.5 x 10-3 to 1.0 mg L-1 were obtained. A total of 31 samples were analyzed and 16 presented from 1 to 5 pesticides.

  9. Possibilities for standardization of {sup 152}Eu by liquid scintillation and gamma spectrometry; Possibilidades para padronização do {sup 152}Eu por cintilação líquida e por espectrometria gama

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira Filho, A.L.; Cruz, P.A.L. da; Silva, R.L. da; Delgado, J.U., E-mail: alfredo@ird.gov.br [Instituto de Radioproteção e Dosimetria (LNMRI/IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. Nacional de Metrologia das Radiações Ionizantes; Lopes, R.T. [Coordenacao de Pos-Graduacao e Pesquisa de Engenharia (LIN/PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentação Nuclear

    2017-07-01

    The {sup 152}Eu has a half-life of 13.5 years and a very complex decay scheme with two branches of decay. It disintegrates in {sup 152}Sm by electronic capture (72.1%) or by emission of positrons (0.027%) and in {sup 152}Gd by beta emission minus (27.9%). The child nucleus, {sup 152}Sm, has 19 excited levels, while {sup 152}Gd has 15. The direct decay of the parent nucleus to the fundamental state of the child nucleus does not exist. The decay of a {sup 152}Eu source results in emissions of 4 KX photons and 132 gamma rays, which is the reason for a lot of true coincidence-sum. The particular interest in this radionuclide is explained by its wide use in the calibration in energy and efficiency of gamma spectrometers with semiconductor detectors, since the range of energy of the emitted photons, varying from 40 to 1769 keV. But, because of such a complex decay scheme, the determination of {sup 152}Eu activity presents many difficulties. The CIEMAT / NIST liquid scintillation counting method and the peak-sum coincidence method, an absolute measurement technique using coincidence counts and photon spectrometry, have been tested in the LNMRI-IRD to standardize {sup 152}Eu solutions.

  10. Caracterização, por espectrometria de massas, dos micropoluentes presentes no esgoto bruto e nos efluentes de um sistema de tratamento combinado anaeróbio-aeróbio

    OpenAIRE

    Leite, Gustavo de Sousa

    2008-01-01

    Substâncias provenientes de fármacos, produtos de limpeza e de higiene pessoal, após utilizadas, atingem o sistema de coleta sanitário e chegam às estações de tratamento onde são, muitas vezes, apenas parcialmente degradadas. Poucos trabalhos são encontrados na literatura nacional sobre a presença de microcontaminantes orgânicos em esgoto sanitário e sua remoção durante o tratamento biológico de efluentes domésticos. Sendo assim, o presente estudo desenvolveu uma metodologia analítica para id...

  11. Design of a computation tool for neutron spectrometry and dosimetry through evolutionary neural networks; Diseno de una herramienta de computo para la espectrometria y dosimetria de neutrones por medio de redes neuronales evolutivas

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz R, J. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Ingenieria Electrica, Av. Ramon Lopez Velarde No. 801, Col. Centro, Zacatecas (Mexico); Martinez B, M. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Av. Ramon Lopez Velarde No. 801, Col. Centro, Zacatecas (Mexico); Gallego, E. [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, Jose Gutierrez Abascal No. 2, E-28006 Madrid (Spain)], e-mail: morvymmyahoo@com.mx

    2009-10-15

    The neutron dosimetry is one of the most complicated tasks of radiation protection, due to it is a complex technique and highly dependent of neutron energy. One of the first devices used to perform neutron spectrometry is the system known as spectrometric system of Bonner spheres, that continuous being one of spectrometers most commonly used. This system has disadvantages such as: the components weight, the low resolution of spectrum, long and drawn out procedure for the spectra reconstruction, which require an expert user in system management, the need of use a reconstruction code as BUNKIE, SAND, etc., which are based on an iterative reconstruction algorithm and whose greatest inconvenience is that for the spectrum reconstruction, are needed to provide to system and initial spectrum as close as possible to the desired spectrum get. Consequently, researchers have mentioned the need to developed alternative measurement techniques to improve existing monitoring systems for workers. Among these alternative techniques have been reported several reconstruction procedures based on artificial intelligence techniques such as genetic algorithms, artificial neural networks and hybrid systems of evolutionary artificial neural networks using genetic algorithms. However, the use of these techniques in the nuclear science area is not free of problems, so it has been suggested that more research is conducted in such a way as to solve these disadvantages. Because they are emerging technologies, there are no tools for the results analysis, so in this paper we present first the design of a computation tool that allow to analyze the neutron spectra and equivalent doses, obtained through the hybrid technology of neural networks and genetic algorithms. This tool provides an user graphical environment, friendly, intuitive and easy of operate. The speed of program operation is high, executing the analysis in a few seconds, so it may storage and or print the obtained information for further analysis and treatment. (Author)

  12. Xanthium strumarium L. antimicrobial activity and carboxyatractyloside analysis through electrospray ionization mass spectrometry Atividade antimicrobiana e análise de carboxiatractilosideo por espectrometria de massas com ionização por electrospray de Xanthium strumarium L

    Directory of Open Access Journals (Sweden)

    R. Scherer

    2009-01-01

    Full Text Available The aim of this work was to evaluate the antimicrobial activity of Xanthium strumarium L. leaf extracts against Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa and Clostridium perfringens, as well as to investigate the presence of the toxic compound carboxyatractyloside in different plant parts. S. aureus and C. perfringens were more sensitive to non-polar than to polar fractions, and there was no difference between extracts for the remaining bacteria. All extracts had strong antimicrobial activity against the evaluated microorganisms. Carboxyatractyloside was found in cotyledons and seeds but not in adult leaves and burrs. Thus, only Xanthium strumarium leaves in adult stage can be used for medicinal purposes.O objetivo do presente trabalho foi avaliar a atividade antimicrobiana de extratos de folhas de Xanthium strumarium L. sobre os microrganismos Staphylococcus aureus, Escherichia coli, Salmonella thyphimurium, Pseudomonas aeruginosa e Clostridium perfringens, bem como verificar a presença do composto tóxico carboxiatractilosideo em diferentes partes da planta. As bactérias S. aureus e C. perfringens foram mais sensíveis às frações não polares do que as polares, sendo que para as outras bactérias não foi verificada diferença entre os extratos. Todos os extratos apresentaram uma forte ação antimicrobiana sobre os microrganismos avaliados. O carboxiatractilosideo foi encontrado nos cotilédones e nas sementes da planta, entretanto, não foi encontrado nas folhas em estádio adulto e na carapaça espinhosa que envolve a semente. Portanto, somente as folhas de Xanthium strumarium na fase adulta podem ser utilizadas para o uso medicinal.

  13. Aplicação de espectrometria de massas com ionização por elétron na análise de alcaloides do mulungu

    Directory of Open Access Journals (Sweden)

    Luís Guilherme Pereira Feitosa

    2012-01-01

    Full Text Available Erythrina verna is a medicinal plant used to calm agitation popularly known as mulungu. We purchased the barks of E. verna from a commercial producer and analyzed the alkaloid fraction of the bark by CG-MS and HRESI-MS. Five erythrinian alkaloids were identified: erysotrine, erythratidine, erythratidinone, epimer, and 11-hydroxieritratidinone. Here we report the compound 11-hydroxieritratidinone for the first time as a natural product.

  14. Antocianinas em extratos vegetais: aplicação em titulação ácido-base e identificação via cromatografia líquida/espectrometria de massas

    Directory of Open Access Journals (Sweden)

    Wesson Guimarães

    2012-01-01

    Full Text Available Anthocyanins extracted from picao, quaresmeira, petunia, flamboyant, purple ipe, lobeira, pata de vaca, jaboticaba, purple cabbage and jambul were evaluated as natural acid-base indicators. Anthocyanins in extracts were identified using HPLC/MS. Clear, rapid change in color at final-point titration was observed for extracts but only picao showed strong change in pH. Indirect determination of carbonate in limestone using a natural indicator was performed and results compared with phenolphthalein indicator and potentiometer titration. Optimal results were obtained with picao but other extracts showed good accuracy and precision.

  15. Validation the quantification of beta emitters activity in urine by scintillation spectrometry in the liquid phase; Validacion de la cuantificacion de actividad de emisores beta en orina mediante espectrometria de centelleo en fase liquida

    Energy Technology Data Exchange (ETDEWEB)

    Sierra, I.; Hernandez, C.; Benito, P.; Lopez, C.

    2013-07-01

    In this paper the methodology used in the validation of the technique for quantifying activity of some beta emitters in urine ({sup 3}H, {sup 1}4C, {sup 3}5S, {sup 3}2P and {sup 9}0Sr) by scintillation spectrometry Liquid Phase (Liquid Scintillation Counting, LSC) is described in bio elimination Laboratory Service CIEMAT Radiation Dosimetry accredited since last year for carrying out assays measure radiation dose based on ISO forth above. (Author)

  16. X-ray fluorescence spectrometry used to assess the dispersion of metals within mining environments; Aplicacion de la tecnica de espectrometria de fluorescencia de rayos-X en el estudio de la dispersion de metales en areas mineras

    Energy Technology Data Exchange (ETDEWEB)

    Margui, E.; Gonzalez-Fernandez, O.; Hidalgo, M.; Pardini, G.; Queralt, I.

    2011-07-01

    One critical factor for success in characterizing metals polluting mining environments so as to be able to eliminate them and subsequently recover these areas depends upon a speedy and correct response in the analysis of samples. Rapid, simultaneous, multi-element analysis can be undertaken using X-ray fluorescence spectrometry, a versatile, non-destructive analytical technique commonly employed to identify both major and minor elements in samples related to environmental studies. An additional advantage of this technique is the possibility of conducting the analysis directly on solid samples, which is extremely convenient when dealing with environmental samples that are difficult to dissolve, such as soils, sediments and mining wastes. Moreover, in recent years the development of spectrometers equipped with digital-signal processors combined with enlarged X-ray production, using better designs for excitation-detection, has contributed to an improvement in instrumental sensitivity, thus allowing us to detect important polluting elements such as Cd and Pb at trace levels. In this paper the authors describe, on the basis of their own experience, some interesting applications of XRF spectrometry for the analysis of several types of environmental samples related to the study of the dispersion of metals within mining environments: (A) analysis of mining wastes, soils and sediments; (B) analysis of samples of vegetation used as bio indicators or related to phyto remediation studies; and (C) analysis of water samples related to mining operations. (Author) 26 refs.

  17. Validation of the alpha spectrometry bio elimination laboratory for measuring activity in excreta; Validacion de la tecnica de espectrometria alfa por el laboratorio de bioeliminacion para la medida de actividad en excretas

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Gonzalez, C.; Sierra Bercero, I.; Benito Alonso, P.; Lopez Zarza, C.

    2011-07-01

    the Laboratory Radiation Dosimetry Service of the CIEMAT is undergoing a process of adapting its working methods and quality assurance to management and technical requirements established in ISO / IEC 17025:2005 with to obtain accreditation shortly ENAC.

  18. Genetic algorithms used to optimize an artificial neural network design used in neutron spectrometry; Algoritmos geneticos utilizados para optimizar un diseno de red neuronal artificial usado en espectrometria de neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Arteaga A, T.; Ortiz R, J. M.; Vega C, H. R., E-mail: tarcicio70@yahoo.co.uk [Universidad Autonoma de Zacatecas, Av. Lopez Velarde 117, 98600 Zacatecas, Zac. (Mexico)

    2016-10-15

    Artificial neural networks (Ann) are widely used; it which consist of an input layer, one or more hidden layers and an output layer; these layers contain neurons and each has connections called weights, where the knowledge are allowed and let to Ann solve problems proposed. These Ann is used to reconstruction of the energy spectrum of neutrons from count rates and develop Bonner sphere neutron dosimetry. Currently, we have developed Ann with high performance and generalization ability. Determine your optimal architecture is usually a difficult task, an exhaustive search of all possible combinations of parameters is rarely possible further training of the neural network with random initial weights can cause two major drawbacks: it can stuck in local minima or converge very slowly. In this project it will be used Genetic Algorithms (Ga); which are based on the principle or analogy of evolution through natural selection and has shown to be very effective in optimizing complex search functions and large spaces or to find a near optimal overall efficiency. The aim is to decrease the architecture in number of hidden neurons and therefore the total number of connections is reducing. The benefits obtained by optimizing the network are that the number of connections would be considerably smaller and thus the computational complexity, hardware integration, resources will be lower such that will allow to be even more viable implemented. To use the Ga three problems must be solve: 1) coding the problem into chromosomes. 2) Construct a fitness function. 3) Proper selection of genetic operators; crossover, selection, mutation. As a result, the scientific knowledge obtained can to be applied to similar problems having a reference parameters used and their impact on the optimization would to be generated. It concluded that the input layer and output are subject to the problem; the Ga propose the optimal number of neurons in the hidden layer without losing the quality of the results. (Author)

  19. Investigação da oxidação eletroquímica de etanol por espectrometria de massas on-line sobre nanoestruturas metálicas

    OpenAIRE

    Daniel Augusto Cantane

    2013-01-01

    Etanol é um combustível químico promissor como uma fonte de geração de energia in situ para a aplicação em células a combustível de baixa temperatura (25 °C). Entretanto, o desenvolvimento das células a combustível utilizando etanol no ânodo têm sido prejudicado devido à baixa eficiência na oxidação eletroquímica do etanol para dióxido de carbono. Com isso, esta tese tem como objetivo sintetizar novos eletrocatalisadores nanoestruturados e investigar a sua atividade catalítica para a elet...

  20. Characterization of a gamma spectrometry monitor LaBr{sub 3} automatic stations for environmental monitoring; Caracterizacion de un monitor de espectrometria gamma de LaBr{sub 3} para las estaciones automaticas de vigilancia ambiental

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, A.; Salvador-Castineria, P.; Roig, M.; Fernandez-Varea, J. M.; Padro, A.

    2011-07-01

    The Institut de Techniques Energetiques (INTE) of the Universitat Politecnica de Catalunya (UPC) is collaborating with the German Radiation Protection (BfS) in order to characterize LaBr{sub 3} detector developed by the BfS for future installation of monitoring networks automatic. This paper presents the results obtained with the monitor installed on the roof of the premises of INTE South Campus located in Barcelona and Monte Carlo simulations that complement its characterization.

  1. Study on the natural radioactivity from the region of Presidente Figueiredo (AM), Brazil, using gamma spectrometry; Estudo da radioatividade natural da regiao de Presidente Figueiredo (AM) utilizando espectrometria gama

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva, Jose Ribamar Silveira

    1999-07-01

    A gamma spectrometry profile was carried out along BR174 highway, that crosses some lithostratigraphic units of the North portion of the Sedimentary Basin of Amazon. Measurements in situ were realized in 116 points, 1 km apart, using a GAD-6 gamma-spectrometer and samples of rocks and soils were collected in geologically representative points, for gamma measurements using a shielded detector of NaI(Tl) available in the Nuclear Geophysics Laboratory of IAG/USP. The criterion used for evaluating the reliability degree of the concentration values of eU (ppm), eTh (ppm) and %K was to establish mathematically detection limits, for all measurement points. Every these points had been located using GPS with accuracy of 50 m to become possible a future detailed study. The purpose of matching portable gamma spectrometer and laboratory determinations was to compare the 2 techniques, using the criterion of detectability limits, and to verify the influence of {sup 222} Rn atmospheric radioactive gas in field measurements. In the case of portable detector, it allows fast measurements and the sensor 'sees' a big volume of material (rock, soil...), that makes it more representative. In some situations where atmospheric phenomena of thermal inversion occurs, measurement can be affected by the {sup 222} Rn cosmic background. Presence of radon daughter elements, associated with aerosols, in this tropical environment (high values of temperature and humidity), where the speed of the wind that could exhaust this gas is practically zero. It is observed that the values of concentration in the some points, got with these 2 techniques, have the same trend, and the stretches where peaks of concentration of K also occur and U and Th are associated with the presence of granite out corps, great boulders, and clay soils from weathering of these rocks. (author)

  2. Determination of trace amounts of selenium in minerals and rocks by flame less atomic-absorption spectrometry; Determinacion de selinio en minerales y rocas por espectrometria de absorcion atomica

    Energy Technology Data Exchange (ETDEWEB)

    Alduan, F. A.; Capdevilla, C.

    1980-07-01

    The determination of trace amounts of selenium In silicate rocks and feldspar by solvent extraction and graphite furnace atomic-absorption spectrometry has been stu- died. Sodium diethyl-ditio carbamate and ammonium pyrrolidine dithiocarbamate have been tried as chelating agents. The best results are achieved when selenium is extracted Into carbon tetrachloride as the sodium diethyldithiocarbamate complex. The method allows to detect 0,75 ppm of selenium in the sample. Recoveries are about 100%. (Author) 7 refs.

  3. Validation of methods to measure uranium isotopes using magnetic sector mass spectrometry with inductively coupled plasma source; Validacion de metodos para medir isotopos de uranio usando espectrometria de masas de sector magnetico con fuente de plasma acoplado inductivamente

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez M, H. [Universidad del Centro de Mexico, Capitan Caldera 75, Col. Tequixquiapan, 78250 San Luis Potosi, SLP (Mexico); Rios L, M. J. [Universidad Autonoma de San Luis Potosi, Facultad de Enfermeria y Nutricion, Unidad de Posgrado, Av. Nino Artillero 130, 78210 San Luis Potosi, SLP (Mexico); Romero G, E. T., E-mail: hector.hernandez520@gmail.com [ININ, Departamento de Quimica, Laboratorio Forense Nuclear, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2017-10-15

    The mass spectrometry technique with inductively coupled plasma source (Icp-Ms) has been widely used to measure isotopic ratios of elements toxic to human health. Reason for which, in this work several measurement methods for the analysis of uranium isotopes in different matrices were implemented using magnetic sector mass spectrometry with inductively coupled plasma source (Icp-SFMS). Groundwater, sediment, soil and urine were the matrices analyzed, which were supplied by intercomparison tests conducted by the IAEA and Association for the Promotion of Quality Control of Medical Biology Analysis in Radio-toxicology. The procedures used in the treatment of soil, sediment and water samples were based on US EPA methods. In the case of the urine sample, the preparation was rapid (1:20 dilution). The average of the results obtained in yield of each matrix was 94, 71, 72 and 78% for water, urine, soil and sediment respectively. In addition, the precision in terms of standard relative deviation was less than 5% and the accuracy was less than 4%. In conclusion, the Icp-SFMS is a very sensitive technique for measuring isotopes of U in different matrices. However, careful tuning is necessary, especially in the mass regions of interest 234, 235 and 238 if an external quantification is considered using natural U solutions. (Author)

  4. Design and construction of prompt-gamma spectroscopy facility applied to the boron determination; Diseno y construccion de una facilidad de espectrometria prompt-gamma aplicada a la determinacion de boro

    Energy Technology Data Exchange (ETDEWEB)

    Poblete, Victor; Henriquez, Carlos; Klein, Juan; Navarro, Gustavo [Comision Chilena de Energia Nuclear, Santiago (Chile). Centro de Estudios Nucleares La Reina, Comision Chis Nucleares La Reina, Comision Chi Reina

    1997-12-31

    A prompt-gamma spectroscopy facility was developed using the south tangential neutron beam of the RECH-1 research reactor for boron determination. The implementation of a thermal neutron beam was performed considering different aspects such as biological protection of working area and the beam collimation for a Ge detector, design and sample holder selection, standards and sample preparation. One ppm of Boron in different samples with counting-rate of 20 minutes and a good accuracy were determined. (author). 5 refs.

  5. Simultaneous determination of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry INa(Ti), in solid samples.; Determinacion de U (Natural), Th (Natural) y Ra-226 en diversos materiales, mediante espectrometria con INa (TI)

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, S.; Navarro, T.; Alvarez, A.

    1991-07-01

    A method has been developed to determine activities of Ra-226, natural uranium and natural thorium by gamma-ray spectrometry. The measurement system has been calibrated using standards specially prepared at the laboratory. It is necessary to assume secular equilibrium in the samples, between Ra-226 and Th-232 and its daughters nuclides, and between U-238 and its immediate daughter Th-234, as the photo peaks measured are those of the daughters. The results obtained indicate that this method can of ter replace the radiochemical techniques used to measure activities in this type of sample. The method has been successfully used to determine these natural isotopes in samples from uranium mills. (Author) 9 refs.

  6. Determination and quantification of impurities found in samples of {sup 124}I using gamma spectrometry; Determinacao e quantificacao de impurezas encontradas em amostra de {sup 124}I usando a espectrometria gama

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ronaldo Lins da; Delgado, Jose Ubiratan; Araujo, Miriam Taina Ferreira de; Laranjeira, Adilson da Silva; Poledna, Roberto; Veras, Eduardo de; Almeida, Maria Candida M. [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Braghirolli, Ana Maria S. [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    {sup 124}I, positron emitter is produced in the IEN/CNEN-RJ and used in diagnosis image of tumors. In this radioisotope production process impurities appear and health agency requires that the level of these characteristics is quantified. These radionuclides emit gamma and X-radiation, allowing the identification and quantitation by gamma spectrometry. With the use of HPGE detector, coupled with the efficiency curve, was identified {sup 125}I and {sup 126}I. The impurity levels measured in the sample were in the range of 0.5% to 90%, respectively, indicating the feasibility of the method for controlling the quality of the radiopharmaceutical.

  7. Combined discrete nebulization and microextraction process for molybdenum determination by flame atomic absorption spectrometry (FAAS); Avaliacao da combinacao da nebulizacao discreta e processos de microextracao aplicados a determinacao de molibdenio por espectrometria de absorcao atomica com chama (FAAS)

    Energy Technology Data Exchange (ETDEWEB)

    Oviedo, Jenny A.; Jesus, Amanda M.D. de; Fialho, Lucimar L.; Pereira-Filho, Edenir R., E-mail: erpf@ufscar.br [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica

    2014-04-15

    Simple and sensitive procedures for the extraction/preconcentration of molybdenum based on vortex-assisted solidified floating organic drop microextraction (VA-SFODME) and cloud point combined with flame absorption atomic spectrometry (FAAS) and discrete nebulization were developed. The influence of the discrete nebulization on the sensitivity of the molybdenum preconcentration processes was studied. An injection volume of 200 μ resulted in a lower relative standard deviation with both preconcentration procedures. Enrichment factors of 31 and 67 and limits of detection of 25 and 5 μ L{sup -1} were obtained for cloud point and VA-SFODME, respectively. The developed procedures were applied to the determination of Mo in mineral water and multivitamin samples. (author)

  8. DETERMINAÇÃO DE POPS E AGROTÓXICOS EM LEITE MATERNO EMPREGANDO CROMATOGRAFIA A GÁS ACOPLADA À ESPECTROMETRIA DE MASSAS COM IONIZAÇÃO QUÍMICA NEGATIVA (GC-NCI-MS)

    OpenAIRE

    Mariela de Souza Viera

    2016-01-01

    A Convenção de Estocolmo foi a primeira atitude mundial a tentar preservar a saúde humana e o ambiente do uso indiscriminado de agrotóxicos, especialmente os poluentes orgânicos persistentes (POPs), que se caracterizam por serem lipofílicos podendo bioacumular nos tecidos adiposos e também no leite materno. Porém, os POPs constituem apenas uma parte dos produtos químicos com potencial de contaminação ambiental e humana uma vez que novas substâncias estão constantemente sendo desenvolvidas e l...

  9. Experimentos simples usando fotometria de chama para ensino de princípios de espectrometria atômica em cursos de química analítica

    Directory of Open Access Journals (Sweden)

    Okumura Fabiano

    2004-01-01

    Full Text Available The purpose of this paper is the development of simple strategies to teach basic concepts of atomic spectrometry. Metals present in samples found in the daily lives of students are determined by flame atomic emission spectrometry (FAES. FAES is an accurate, precise, and inexpensive analytical method often used for determining sodium, potassium, lithium, and calcium. Historical aspects and their contextualization for students are also presented and experiments with samples that do not require pre-treatment are described.

  10. A gamma-Ray spectrometer system for low energy photons by coupling two detectors; Un sistema de espectrometria gamma de fotones de baja energia mediante acoplamiento de dos detectores

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, A; Palomares, J; Romero, L; Travesi, A

    1986-07-01

    This report describes the study performed to obtain a composite (sun uma) spectrum from a Low Energy Gamma Spectrometry System by coupling two planar Germanium detectors. This disposition allows to obtain a high counting efficiency for the total system. It shows the improvement achieved by the synthetic spectrum which is obtained by adding the two original spectra through the LULEPS code. This code corrects the differences (channel/energy) between both two spectra before performing the addition. (Author) 6 refs.

  11. Determination of {sup 226}Ra by gamma spectrometry: study of packaging vial of sample for analysis; Determinacao de {sup 226}Ra por espectrometria gama: estudo do recipiente de acondicionamento de amostra para analise

    Energy Technology Data Exchange (ETDEWEB)

    Carneiro, Andre Cavalcanti

    2015-07-01

    Determination of radioactivity levels of {sup 226}Ra by gamma spectrometry in a sample is based on measurements of {sup 214}Pb and {sup 214}Bi, daughters of {sup 222}Rn. Because radon is a gas, it can leak from the sample vial or accumulate on the upper empty it. If the vial has any crack, there will be loss of gas, which will cause error in determining the {sup 226}Ra concentration. One possible cause of cracks in the vials, that houses standards and samples, is the radiolysis action in the vial material, usually a polymer. As the demand {sup 226}Ra analysis in different matrices (geological samples, food, plants, etc.) is increasing, it was decided to study some polymer vials available on the market, to verify the feasibility to be used when is applied the analysis method using gamma spectrometry. Four types of polymer vials have been studied. The radiation doses in walls of the vials caused by natural radionuclides present in the sample were simulated using gamma irradiation. Tests, such as compressive strength test and tightness, were applied to the irradiated and non-irradiated vials. First, to verify the effect of radiolysis on the vial material and also if there was {sup 222}Rn diffusion in their walls. These preliminary results pointed out that the acrylic vials are the best option of packaging samples for analysis. This study should be repeated in a larger number of samples for a better evaluation. (author)

  12. Development of multichannel system for nuclear radiation spectrometry based on an embedded control and acquisition device Myrio-1900; Desarrollo de sistema multicanal para espectrometria de radiacion nuclear basado en un dispositivo embebido de control y adquisicion MyRIO-1900

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez D, S.

    2016-07-01

    This work describes the design a multichannel analyzer system 4096 channels (Mca) for gamma radiation spectrometry. The multichannel analyzer has as its main component an embedded company National Instruments model NI (Myrio-1900) module, which is integrated by a step of converting analog to digital signals (A / D) and digital-to-analog (D / A) a programmable gate array, and a processor real time (Rt). Through this module the pulses generated by the detector to be processed and subsequently forming the multichannel analyzer are acquired. In addition, a graphical user interface designed to make more use friendly system from a personal computer (Pc), embedded programming module and the user interface was done with the LabVIEW programming environment. tests with different sources of radiation ({sup 60}Co, {sup 226}Ra, {sup 137}Cs) and semiconductor detectors (Ge) and scintillation (Na) were made. Getting results satisfactory. (Author)

  13. Determination of rubidium and strontium in geological materials by X-Ray fluorescence spectrometry; Determinacion de rubidio y estroncio en materiales geologicos mediante espectrometria de fluorescencia de rayos X

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M.

    1979-07-01

    In order to determine whole-rock ages by the Rb/Sr procedure, an X-ray fluorescence spectrometry method for the determination of both elements has been developed. The samples are pressed into boric acid backed and ringed pellets with this material as a binding agent. Matrix corrections are made following the determination od the mass absorption coefficients, based on the intensity of the Compton-scattered peak of MoK{alpha}. or MoK{beta}{sub 1}.3. The U. S. Geological Survey granodiorite GSP-1 is used as a reference standard. Spectral-line interferences have been carefully studied and the empirical correction factors determined. A BASIC language program for calculating the Rb and Sr concentrations and the Rb/Sr ratios has been written. (Author) 7 refs.

  14. Crystal Dynamics from Neutron Spectrometry; Etude de la dynamique des cristaux par la spectrometrie neutronique; Izuchenie voprosov dinamiki kristallov metodami nejtronnoj spektrometrii; Estudio de la dinamica de redes cristalinas por espectrometria neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Woods, A. D.B. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    1963-01-15

    This paper reviews investigations carried out at Chalk River on the lattice dynamics of various crystals including lead, sodium, alkali halides, semi-conductors, and other more complex compounds. Analysis of the low temperature results (-{approx}100{sup o}K) gives considerable insight into the nature of the interatomic forces. In sodium, a simple metal, the interatomic forces are very nearly derivable from a potential. Lead, a more complicated metal, has extremely long range forces accompanied by strong electronic effects. At higher temperatures anharmonic effects are very pronounced in both metals, especially in lead. The alkali halide results can be interpreted on a ''shell'' model, with polarizable ions. Even at low temperature neutron groups corresponding to the longitudinal optical modes. (author) [French] Dans ce memoire, l'auteur decrit les recherches faites a Chalk River sur la dynamique des reseaux de certains cristaux, y compris le plomb, le sodium, les halogenures alcalins, les semi-conducteurs et d'autres composes complexes. L'analyse des resultats obtenus a basse temperature (environ 100{sup o}K) fournit de nombreux renseignements sur la nature des forces interatomiques. Dans le sodium (metal simple), les forces interatomiques peuvent presque etre derivees d'un potentiel. Dans un metal plus complique, tel que le plomb, on trouve des forces ayant une portee extremement grande et comportant des effets electroniques marques. A des temperatures plus elevees, il se produit des effets anharmoniques tres prononces dans les deux metaux et particulierement dans le plomb. On peut interpreter les resultats obtenus pour les halogenures alcalins en se fondant sur le modele en couche comportant des ions polarisables. Meme aux basses temperatures, les groupes de neutrons correspondant aux modes optiques longitudinaux possedent des largeurs dependant de la temperature, que l'on ne comprend pas encore parfaitement. (author) [Spanish] Los autores pasan revista a las investigaciones realizadas en Chalk River sobre la dinamica reticular de varios cristales, entre ellos plomo, sodio, haluros alcalinos, semiconductores-y otros compuestos mas complejos. El analisis de los resultados obtenidos a baja temperatura ({approx}100{sup o}K) permite formarse una idea mas cabal de la naturaleza de las fuezas interatomicas. En el sodio, metal simple, dichas fuerzas pueden deducirse con considerable precision a partir de un potencial. En el plomo, metal mas complejo, existen fuerzas de largo alcance acompanadas de fuertes efectos electronicos. A temperaturas mas elevadas, los efectos anarmonicos son muy pronunciados en ambos metales, sobre todo en el plomo. Los resultados obtenidos con los haluros alcalinos pueden interpretarse segun el modelo de capas con iones polarizables. Incluso a bajas temperaturas, los grupos de neutrones correspondientes a los modos opticos longitudinales presentan amplitudes dependientes de la temperatura que aun no se han podido interpretar en detalle. (author)

  15. Determination of Cd and Pb in canned pineapple by atomic absorption spectroscopy using a graphite oven; Determinacion de Cd y Pb en pina enlatada por espectrometria de absorcion atomica utilizando horno de grafito

    Energy Technology Data Exchange (ETDEWEB)

    Linares P, G.; Sanchez P, L.; Benavides M, A.; Acosta L, C. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    Owing to the food susceptibility to be contaminated it is necessary to realize pursuit studies or frequent monitoring about the content of certain metals which represent health risks by its toxicological effects in the human being and another living organisms. In this work the cadmium and lead concentrations are determined in six national brands of canned pineapple analysing separately sugar sirup and the fruit. (Author)

  16. Methodology for measuring surfaces using in situ gamma spectrometry in nuclear and radiological emergencies; Metodologia de medida de superficies mediante espectrometria gamma in sit en emergencias radiologicas y nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Yague, L.; Navarro, N.; Perez, C.; Perez-Cejuela, P.; Vico, A.; Maquez, J. L.; Alvarez, A.

    2013-07-01

    CIEMAT has an environmental mobile unit for measurements of ambient dose rate and activity concentration in air. In addition, recently it included the ability to surface concentration measurement. This measure is particularly useful for making decisions about emergency decontaminate surfaces according to the criteria of the DBRR. (Author)

  17. Determination of activity by gamma spectrometry of radionuclides present in drums of residues generated in nuclear centrals; Determinacion de actividad por espectrometria gamma de radionucleidos presentes en tambores de residuos generados en centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, J.C.; Fernandez, J. [Autoridad Regulatoria Nuclear, Av. Del Libertador 8250, Ciudad Autonoma de Buenos Aires (Argentina)]. e-mail: jaguiar@cae.arn.gov.ar

    2006-07-01

    The generation of radioactive residuals in nuclear centrals as CNA I (Atucha I Nuclear Central) and CNE (Embalse Nuclear Central) makes that the measurement of those radionuclides has been a previous stage to the waste management. A method used in those nuclear centrals it is the gamma spectrometry with HPGe detectors, previous to the immobilization of the residual in a cemented matrix, with this the contact with the external agents and its possible dispersion to the atmosphere in the short term is avoided. The ARN (Nuclear Regulatory Authority) of Argentina it carries out periodically intercomparisons and evaluations of the measurement and procedures systems used in the nuclear power stations for the correct measurement and determination of activity of radioactive residuals by gamma spectrometry. In this work an independent method of measurement is exposed to the nuclear power stations. To determine the activity of the residuals by gamma spectrometry deposited in drums, it is required of the precise knowledge of the efficiency curve for such geometry and matrix. Due to the RNA doesn't have a pattern of these characteristics, a mathematical model has been used to obtain this efficiency curve. For it, it is necessary to determine previously: 1) the geometric efficiency or solid angle sustained by the source-detector system (drum-detector) applying a mathematical model described in this work. 2) To estimate the auto-attenuation factor that present the photons in the cemented matrix, these calculations are carried out with a simple equation and its are verified with the Micro Shield 6.10 program. The container commonly used by these nuclear power stations its are drums for 220 liters constructed with SAE 1010 steel and with a thickness of 0.127 cm, with an approximate weight 7.73 Kg., internal diameter of 57.1 cm, and height: 87 cm. The results obtained until the moment register a discrepancy from 5 to 10% with relationship to the measurements carried out by the nuclear power stations. (Author)

  18. Proposta de um modelo de simulação de análises de espectrometria de massa para aulas práticas de Bioquímica no ensino superior

    OpenAIRE

    Barbosa, Eduardo Fernandes

    2015-01-01

    Mass spectrometry is a very important tool to elucidate many aspects of modern biochemistry. This proposal aims to enable that any graduate student get an initial contact with this technique through simulations in practical classes. Low cost and simple implementation enable and facilitate its application. The student can understand the basic principles of mass spectrometry and enable data interpretation obtained through this methodology. This simulation can provide to students an initial cont...

  19. Oxidação eletroquímica de etanol em temperatura ambiente e intermediária: estudo quantitativo das vias reacionais por espectrometria de massas on-line

    OpenAIRE

    Adriana Coêlho Queiroz

    2016-01-01

    Na primeira parte do trabalho, foram investigados materiais ativos para eletro-oxidar etanol e acetaldeído seletivos para a rota C2 (Carbono 2) e, também, ativos para eletro-oxidar hidrogênio molecular, visando a aplicação em células a combustível de hidrogênio indireto. Neste tipo de célula, um processador de combustível externo desidrogena o etanol e os produtos desta reação, contendo H2, acetaldeído e, possivelmente, etanol residual, são direcionados para alimentar o ânodo. Neste sentido, ...

  20. Cu,Cr and As determination in preserved woods (Eucalyptus ssp.) by X-ray fluorescence spectrometries; Determinacao de cobre, cromo e arsenio em madeira preservada (Eucalyptus sp.) pelas espectrometrias de fluorescencia de raios X

    Energy Technology Data Exchange (ETDEWEB)

    Pereira Junior, Sergio Matias

    2014-07-01

    Brazil produces around 2.2 millions of cubic meters of treated wood to meet the annual demand of railway, electric, rural and construction sectors. The most used wood species are eucalyptus (Eucalyptus ssp.) and pine (Pinus ssp.).The treated woods used for poles, sleepers, fence posts and plywoods should be according to Brazilian norms requirements. The most usual wood preservative products used in Brazil are CCA (chromated copper arsenate) and CCB (copper chromium and boron salt). The analytical methods, such as flame atomic absorption spectrometry (FAAS), plasma inductively coupled optical emission spectrometry (ICPOES) and X-ray fluorescence spectrometry (XRFS) have been used for the analytical control of those treatment processes. In this work, the eucalyptus trees (Eucalyptus ssp) samples was obtained from Minas Gerais State, Brazil, cut plantation areas. Under pressure, eucalyptus wood samples were submitted to different concentration of CCA solution reaching 3.9, 6.7, 9.1, 12.4 and 14.0 kg of CCA by m-³ sapwood retentions. Samples in cylinders and sawdust forms were obtained from treated wood samples. Copper, chromium and arsenic determination was performed using the energy dispersive X-ray fluorescence spectrometry (EDXRFS), portable X-ray fluorescence spectrometry (PXRFS), flame atomic absorption spectrometry (FAAS) and instrumental neutron activation analysis. In this work, the method of analysis, sensitivity, precision and accuracy performances of the related techniques were outlined. (author)

  1. Influence of soil composition in the determination of chromium by atomic absorption spectrometry with flame air / acetylene; Influencia de la composicion del suelo en la determinacion de cromo por espectrometria de absorcion atomica con llama aire/acetileno

    Energy Technology Data Exchange (ETDEWEB)

    Duran Sosa, Ibis; Granda Valdes, Mayra [Departamento de Quimica Analitica, Facultad de Quimica, Universidad de La Habana, La Habana (Cuba); Pomares Alfonso, Mario Simeon, E-mail: mpomares@imre.oc.uh.cu [Instituto de Ciencias y Tecnologia de Materiales, Universidad de La Habana, La Habana (Cuba)

    2014-07-01

    The Air-acetylene Flame Atomic Absorption determination of chromium is a complex task, being strongly influenced by sample composition and instrumental conditions. The objective of this work was to study the influence of Al, Ca, Fe, K, Mg, and Na on the absorption of chromium in the air-acetylene flame, both separately and combined in solution, when acetylene flow and burner height vary. Dissolutions of the mixtures simulated the composition of four soils from the Quibu River Basin in Havana, Cuba. Chromium absorption first increased and then decreased with increment of acetylene flow for shorter burner heights (∼ 2-4 mm); while a continuous increase was observed for larger heights (> 4 mm). This behavior was the same in the presence and absence of interfering chemical element, mentioned above. On the other hand, the dependence of the magnitude of the interference with acetylene flow and burner height was complex and dependent on the interfering element, particularly at larger heights where the behavior of Al was remarkably different. The interference of the four mixtures of Al, Ca, K, Fe, Mg and Na decreased in comparison to individual interfering effects and was less dependent on acetylene flow and burner height. Finally, a significant reduction of interference on chromium determination in soil samples was achieved by an adequate selection of acetylene flow and burner height.

  2. Um novo método para quantificar mercúrio orgânico (Hg orgânico empregando a espectrometria de fluorescência atômica do vapor frio

    Directory of Open Access Journals (Sweden)

    Márcia Cristina Bisinoti

    2006-12-01

    Full Text Available In this work a simple and sensitive procedure to extract organic mercury from water and sediment samples, using methylene chloride in acidic media followed by CVAFS quantification has been developed. The method was evaluated for possible interferents, using different inorganic mercury species and humic acid, no effects being observed. The detection limit for organic mercury was 160 pg and 396 pg for water and sediment samples respectively. The accuracy of the method was evaluated using a certified reference material of methylmercury (BCR-580, estuarine sediment. Recovery tests using methylmercury as surrogate spiked with 1.0 up to 30.0 ng L-1 ranged from 90 up to 109% for water samples, whereas for sediments, recoveries ranged from 57 up to 97%.

  3. Raman Investigation of Structural Photoinduced Irreversible Changes of Ga(10)Ge(25)S(65) Chalcogenide Glasses

    Science.gov (United States)

    2001-06-01

    Brazil cDepto de Quimica - Universidade Federal de Juiz de Fora, Juiz de Fora, MG- Brazil dEscola de Engenharia de Sao Carlos- - Universidade de Sao Paulo...Inorganic Materials IIC ASCR and ICT, Pelleova 24, Prague 6, Czech Republic blnstituto de Quimica - UNESP- C.P. 355, CEP: 14801-970, Araraquara, SP

  4. Development of New Photorefractive Polymer Materials

    Science.gov (United States)

    2015-05-19

    and the Di-OH-C8-PDI (Pery-OH) provided by Dr. Ziolo at Centro de Investigacion en Quimica Aplicada. Figure 19 shows absorbance measurements of the...Additional sensitizers were provided by Dr. Ziolo at Centro de Investigacion en Quimica Aplicada, Fe5PPV and 3BzC60, with molecules

  5. Silicon-Based Optoelectronic Materials, Symposium Held in San Francisco, California on April 12-14, 1993. Materials Research Society Symposium Proceedings, Volume 298

    Science.gov (United States)

    1993-12-14

    Pierre Basmaji and Sirgio C. Zilio Instituto de Ffsica e Quimica de Sio Carlos - USP Caixa Postal 369, 13560-970 - Sio Carlos, SP, Brazil "Vilnius...Ffsica e Quimica de Sko Carlos Departamento de Fisica e Ci~ncia dos Materiais Universidade de Sio Paulo, Caixa Postal 369 13560-970 Sio Carlos, SP

  6. National Fuel Cell Seminar (1983) Program and Abstracts Held at Orlando, Florida on 13-16 November 1983.

    Science.gov (United States)

    1983-01-01

    January 1982 - December 1983), supported by CNPq Brazil, carrying out research for Ph.D. degree in Chemistry from Instituto de Fisica e Quimica de Sao...Carlos, USP, Brazil. 2. Visiting Scientist at Los Alamos National Laboratory (May - July 1983) from Instituto de Fisica e Quimica de Sao Carlos, USP

  7. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Lotfali Saghatforoush1 Laura Valencia Matarranz2 Firoozeh Chalabian3 Shahriare Ghammamy4 Fatemeh Katouzian5. Department of Chemistry, Payame Noor University, 19395-4697, Tehran, I.R. of Iran; Departamento de Quimica Inorganica, Facultad de Quimica, Universidade de Vigo, 36310 Vigo Pontevedra, Spain ...

  8. Determination of Methylmercury Traces in Biological Matrix: Chemical Extraction and Nuclear Quantification with the Neutron Activation Analysis Technique; Determinacion de Trazas de Metilmercurio en Matriz Biologica: Extracion Quimica y Cuantificacion Mediante la Tecnica Nuclear de Analisis por Activacion Neutronica (AANI)

    Energy Technology Data Exchange (ETDEWEB)

    Soldati, A L [Instituto Balseiro, Universidad Nacional de Cuyo, Centro Atomico Bariloche (Argentina)

    2002-07-01

    Mercury is present in the environment as a result of the human and natural activities.The total amount of Hg present in the biosphere has been incremented three times since the industrial era, and now it is affecting in a global sense all the ecosystem.One of the main entrance of Hg in the human diet is the consumption of fish and other marine creatures.Most of the ingested Hg is mono methylmercury (MeHg), which is one of the most toxic forms in which this element could be found because it crosses membranes.Since the toxicity levels are low, the determination of concentrations of total Hg and Me Hg require very careful sampling, sample conditioning and analytical procedures to prevent either losses or contamination, or the degradation of the Hg species.In this work, we implemented a chemical Me Hg extraction procedure, using a ionic exchange resin, with three different types of fish tissue: muscle, liver and hepato pancreas.After Me Hg extraction, the determination and quantification was made by Instrumental Neutron Activation Analysis, by measuring the {sup 197} Au, y el {sup 203} Tl deexcitation s, created through the radioactive decay of the isotopes {sup 197} Hg y {sup 203} Hg.The influence of several parameters on the overall extraction process, such as velocity of passage through the ionic exchange column and the acid concentration used in the extraction was evaluated.Regarding the INAA determinations, a choice was made for the irradiation, decay and counting times, neutron and gamma doses, and the counting geometry The detection limit found for this technique (dry weight) is 140 pg MeHg/g. The Hg contents of the muscle samples were measured with the 279 keV emission of the product of the {sup 202} Hg(n,g){sup 203} Hg reaction, with a recovery of (100 {+-} 13)%. Liver and Hepato pancreas samples were measured with the 77 keV gamma emission of the {sup 197} Hg, checking this result with the 67 y 69 keV X emissions from the same isotope.The liver samples needed an extra vacuum filtering process during the extraction.The filtering process was implemented and with no significant effects of losses or contamination.The recoveries obtained for both types of samples are close to 100%. However, due to the lower Hg contents in these samples, the uncertainties are higher than in the muscle samples measurements (20% for livers and 50% for hepato pancreas) because the Me Hg amounts analyzed are near the detection limit of this technique.

  9. Physical and chemical characterization of pastes of bone cements with ZrO{sub 2}; Caracterizacion fisica y quimica de pastas de cementos oseos con ZrO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Quinto H, A. [Instituto Tecnologico de Zacatepec, A.P. 45, 62900 Zacatepec, Morelos (Mexico); Pina B, M.C. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360, 04510 Mexico D.F. (Mexico)

    2003-07-01

    Setting times and temperature of sixteen calcium phosphate cements added with ZrO{sub 2} were evaluated. Their behaviors were analysed to be used like injectable formulations in surgery of bone. Two cements of calcium phosphates enriched with ZrO{sub 2} with the best characteristics in setting times and temperature, were mechanically tested after 1 and 7 days of prepared. Density was determined using a pycnometer, chemical composition was determined by X-ray diffraction and the molecular structure was determined by infrared spectroscopy. (Author)

  10. Extraction of pigments from seeds of Bixa orellana L.: an alternative for experimental courses in organic chemistry; Extracao de pigmentos das sementes de Bixa orellana L.: uma alternativa para disciplinas experimentais de quimica organica

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Charllyton Luis S. da; Chaves, Mariana H. [Piaui Univ., Teresina, PI (Brazil). Dept. de Quimica]. E-mail: mariana@ufpi.br

    2005-02-01

    This paper describes methodologies for the extraction and characterization by TLC, UV-VIS, IR and NMR of bixin from Bixa orellana L. (urucum) seeds. Based on the results, the extraction with NaOH 5% is the fastest, uses low cost materials, requires two to four laboratory hours and is a useful alternative for an experimental Organic Chemistry discipline. (author)

  11. Chemical modification of high molecular weight polyethylene through gamma radiation for biomaterials applications; Modificacao quimica de polietileno de alto peso molecular atraves de radiacao gama para aplicacao em biomateriais

    Energy Technology Data Exchange (ETDEWEB)

    Raposo, Matheus P.; Rocha, Marisa C.G., E-mail: matheusmerlim@hotmail.com [Universidade Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Instituto Politecnico

    2015-07-01

    Ultra high molecular weight polyethylene has been used in the medical field due to its high mechanical properties compared to the other polymers. Its main application is in the development of orthopedic implants, which requires high resistance to abrasion. One of the most used methods is the introduction of crosslinks in the polymer through gamma irradiation. In order to prevent oxidation reactions, studies have been developed using tacoferol (vitamin E) as an antioxidant for the material. The ascorbic acid (vitamin C), however, has been appointed as a viable alternative for vitamin E. In this work, a high molecular weight polyethylene grade (HMWPE) and polyethylene samples formulated with vitamin C were submitted to gamma radiation. Thermodynamic-mechanical methods and gel content determinations were used to characterize the samples obtained. The sample containing 1% of vitamin C and irradiated with 50 KGy of gamma radiation presented the highest content of crosslinks. (author)

  12. Study of film graphene/graphene oxide obtained by partial reduction chemical of oxide graphite; Estudo de filme de grafeno/oxido de grafeno obtido por reducao quimica parcial do oxido de grafite

    Energy Technology Data Exchange (ETDEWEB)

    Gascho, J.L.S.; Costa, S.F.; Hoepfner, J.C.; Pezzin, S.H., E-mail: juliagascho@hotmail.com [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2014-07-01

    This study investigated the morphology of graphene/graphene oxide film obtained by partial chemical reduction of graphite oxide (OG) as well as its resistance to solvents. Films of graphene/graphene oxide are great candidates for replacement of indium oxide doped with tin (ITO) in photoelectric devices. The OG was obtained from natural graphite, by Hummer's method modified, and its reduction is made by using sodium borohydride. Infrared spectroscopy analysis of Fourier transform (FTIR), Xray diffraction (XRD) and scanning electron microscopy, high-resolution (SEM/FEG) for the characterization of graphene/graphene oxide film obtained were performed. This film proved to be resilient, not dispersing in any of the various tested solvents (such as ethanol, acetone and THF), even under tip sonication, this resistance being an important property for the applications. Furthermore, the film had a morphology similar to that obtained by other preparation methods.(author)

  13. Chemical and physical analysis on hard tissues after irradiation with short pulse Nd:YAG laser; Alteracoes quimicas e fisicas de tecidos duros irradiados por laser de neodimio chaveado

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Andrea Antunes

    2003-07-01

    This work reports on a study that was designed to investigate chemical, physical and morphological alterations in the dental enamel surface. The influence of application of laser in enamel surface by microscopic technical, X-ray fluorescence for chemical analysis, physical property as well as hardness and thermal analysis with Nd:YAG laser is also pointed out. A prototype of Nd:YAG (Q-switched) laser developed at the Center of Lasers and Applications - Institute of Energetic and Nuclear Research, aiming applications in the Medical Sciences that typical wavelength of 1.064 nm was used. The modifications in human dental enamel chemical composition for major and trace elements are here outlined. The accuracy of procedures was performed by analysis of natural hydroxyapatite as standard reference material. The identification and quantification of the chemical elements presented in the dental tissue samples were performed trough EDS, XRF and INAA. We determined the rate Calcium/Phosphorus (Ca/P) for different techniques. We performed an analysis in different regions of the surface and for different areas allowing a description of the chemical change in the total area of the specimen and the assessment of the compositional homogeneity of the each specimen. A comparison between XRF and INAA is presented. Based on morphological analysis of the irradiated surfaces with short pulse Nd:YAG laser we determined the area surrounded by the irradiation for the parameters for this thesis, and this technique allowed us to visualize the regions of fusion and re-solidification. The energy densities ranged from 10 J/cm{sup 2} to 40 J/cm{sup 2}, with pulse width of 6, 10 e 200 ns, and repetition rates of 5 and 7 Hz. In this thesis, FTIR-spectroscopy is used to analyze powder of mineralized tissue as well as enamel, dentine, root and cementum for human and bovine teeth after irradiation with short-pulse Nd:YAG laser. Characteristic spectra were obtained for the proteins components and mineral compound of dental tissue. We determined the rate between the area of the control and irradiated bands and the results pointed out an enlargement in the area below the curve of the distinct conditions of irradiation. We monitored the raise of temperature caused by irradiation using the T-thermocouple fixed on the pulpar chamber. The result obtained for the highest value of the energy density was inferior to 5 deg C, which indicates that its use is viable without damage on the dental pulp. Based on models already presented in the literature for the heat transfer we performed numeric simulations using the irradiation parameters from this thesis and we simulated the temperature variation in deepness and for different exposition time on the enamel and the dentine. (author)

  14. Evolution of {sup 222} Rn and chemical species related with eruptive processes of the Popocatepetl volcano; Evolucion de {sup 222} Rn y especies quimicas relacionadas con procesos eruptivos del volcan Popocatepetl

    Energy Technology Data Exchange (ETDEWEB)

    Aranda Z, P

    1998-10-01

    The study of the water quality for human consumption has always been great importance, considering the factors that can affect water quality as aquifers recharge and underground permeability. In this work, the behavior of three water springs related with the Popocatepetl volcano were studied within April 1997 and March 1998. The spring in Paso de Cortes in the municipality of Amecameca, State of Mexico, and the springs of Atlimeyaya and Axocopan in Atlixco, State of Puebla; the water of these last two springs is used for human consumption. The content of radon in water was determined by means of liquid scintillation, and a concentration of 1.22 Bq/l was found in the spring of Atlimeyaya, which represents 2 % of the maximum permissible level established by ICRP. A significant increase was observed in the Paso de Cortes spring in the month of July 1997. The content of radium, was determined by means of gamma spectrophotometry and small quantities of this element (<0.11 Bq/l) were found. Water chemical analysis also included usual physical-chemical parameters determination by means of conventional methods. The spring of Axocopan, was found to have the major level of minerals, followed by Atlimeyaya and finally the Paso de Cortes spring, which is supplied by recent infiltrated water. Fluoride level showed a peak high level in concentration during the months of October and November, time in which infiltration due to rain is low; concentration level found was above the maximum permissible level established by Mexican authorities for this compound. The other chemical species determined were: Ca{sup 2+} , Mg{sup 2+} , K{sup +}, Na{sup +}, H C O{sub 3} {sup -} , Cl{sup -} , S O{sub 4} {sup -} {sup 2} , Li, B, Sc, Ti, V, Rb, Sr and Ba, primarily, which did not show any significant variation with the change of seasons. No important variations in the concentration of radon, radium or for other volcanic activity related species were found in the entire study. (Author)

  15. The use of glycerol in PET chemical recycling with the prospect of the polymeric membranes production; Utilizacao de glicerol na reciclagem quimica de PET visando a producao de membranas polimericas cationicas

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Agne R. de; Consentino, Vinicius M.; Muniz, Aline S.; Sakae, George H.; Oliveira, Angelo R.S.; Cesar-Oliveira, Maria Aparecida F. [Universidade Federal do Parana - UFPR, Centro Politecnico, Curitiba, PR (Brazil)], e-mail: mafco@ufpr.br

    2011-07-01

    The recent interest in alternative sources of renewable energy of unlimited duration and with a low environmental impact, has led to a rise in the use and production of biodiesel. This requires an increase in the availability of glycerine in the market. This involves a study of new applications to increase the consumption of this raw material which can be linked to solving a serious environmental problem - the unsuitable disposal of post-consumption PET packages. Parallel to this, combustible cell technology is proving to have promising results, particularly in the area which uses polymeric electrolytes. The polymeric proton exchange membrane is currently most widely used in Nafion. However, this entails very high costs. By bringing together these important requirements in the energy sector, this study demonstrates how the development of aromatic sulfonate polyesters obtained from the chemical recycling of poly(ethylene terephthalate) with an aromatic derivative of glycerol. (author)

  16. Evaluation of the physico-chemical properties of nanocomposites of low density linear polyethylene and organophilic montmorillonite obtained by fusion; Avaliacao das propriedades fisico-quimicas de nanocompositos de polietileno linear de baixa densidade e montmorilonita organofilica obtidos por fusao

    Energy Technology Data Exchange (ETDEWEB)

    Arndt, Aline; Sandrin, Bianca M.; Pezzin, A.P.T., E-mail: anapezzin@yahoo.com.br [Universidade da Regiao de Joinville (UNIVILLE), SC (Brazil); Meier, Marcia M. [Universidade do Estado de Santa Catarina (UESC), Joinville, SC (Brazil). Departamento de Quimica; Balzer, Palova S. [Centro Universitario Unisociesc, Joinville, SC (Brazil). Departamento de Engenharia Mecanica; Tavares, Maria I.B. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Laboratorio de Solucoes em Ralaxometria

    2016-07-01

    In this project they were produced and characterized nanocomposite organoclay applied to linear low density polyethylene in order to improve their physicochemical properties. Samples were produced by means of extrusion and injection process, varying proportions of nanoclay (2; 2.5; 3.0 and 3.5%) in LLDPE. Samples nanocomposites were characterized by TGA, DSC and Flammability test (UL-94). The TGA analysis showed that adding nanoclay increased thermal stability, especially for LLDPE / OMMT2,0 sample increased thermal stability at 4.4%. By DSC it was found that samples with nanoclay incorporation did not affect the Tm of LLDPE, though the increase of nanoclay raised the degree of crystallinity of the samples 52.7% in LLDPE / 2.5 OMMT sample. The flammability results show that the sample LLDPE / OMMT 2.0 showed a decrease of 37.77% in the flame propagation velocity. The NMR showed that the samples up LLDPE / 2.5 OM has an exfoliated nanocomposite formation. (author)

  17. Isolation and partial chemical analysis of exopolysaccharides from cultivated marine diatom Coscinodiscus wailesii (Coscinodiscales, Bacillariophyta); Isolamento e analise quimica parcial de exopolissacarideos da diatomacea marinha cultivada Coscinodiscus wailesii (Coscinodiscales, Bacillariophyta)

    Energy Technology Data Exchange (ETDEWEB)

    Marson-Ascencio, Poliana G.; Ascencio, Sergio Donizeti [Universidade Federal do Tocantins, Palmas, TO (Brazil); Baggio, Selma Faria Zawadzki, E-mail: polianamarson@uft.edu.br [Universidade Federal do Parana, Curitiba, PR (Brazil). Centro Politecnico. Dept. de Bioquimica e Biologia Molecular

    2012-07-01

    The marine diatom Coscinodiscus wailesii has attracted ecological interest because their blooms affect fishing areas. The aim of this work was the isolation, extraction and partial chemical characterization of soluble exopolysaccharide and bound exopolysaccharide from C. wailesii. Cultures were grown in Guillards f/2 medium under controlled conditions of temperature, aeration, photo period and light intensity. Percentage of carbohydrate, uronic acids, sulfates groups and cellular lipids was determined. Ion exchange chromatography of exopolysaccharides produced three fractions whose partial chemical structures were disclosed using {sup 13}C NMR and methylation techniques. (author)

  18. Synthesis of liquid crystals derived from nitroazobenzene: a proposed multistep synthesis applied to organic chemistry laboratory classes; Sintese de cristais liquidos derivados do nitroazobenzeno: uma proposta de sintese multi-etapas aplicada as aulas de quimica organica experimental

    Energy Technology Data Exchange (ETDEWEB)

    Cristiano, Rodrigo; Cabral, Marilia Gabriela B.; Aquino, Rafael B. de; Cristiano, Claudia M.Z., E-mail: rcristiano@quimica.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Departamento de Quimica

    2014-07-01

    We describe a synthetic route consisting of five steps from aniline to obtain liquid crystal compounds derived from nitroazobenzene. Syntheses were performed during the second half of the semester in organic chemistry laboratory classes. Students characterized the liquid crystal phase by the standard melting point techniques, differential scanning calorimetry and polarized optical microscopy. These experiments allow undergraduate students to explore fundamentally important reactions in Organic Chemistry, as well as modern concepts in Chemistry such as self-assembly and self-organization, nanostructured materials and molecular electronics. (author)

  19. Analysis of the physico-chemical quality Enalapril and Simvastatin drugs manipulated in magistral pharmacies from Belo Horizonte, MG, Brazil; Analise da qualidade fisico-quimica dos medicamentos Enalapril e Sinvastatina manipulados em farmacias magistrais de Belo Horizonte, MG, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Tatiana Cristina Bomfim

    2013-07-01

    The increasing expansion of compounding pharmacy associated with several reports on variances in the quality of compounded drugs demonstrates the need for verification of quality, safety and efficacy of these products. In this work, physical and chemical analyzes were performed to evaluate the quality of some capsules manipulated enalapril and simvastatin, acquired in five pharmacies in Belo Horizonte /Brazil. Among the analyzes are pharmacopoeial tests for appearance, identification, determination of weight, content, related compounds and uniformity of dosage units, and was also performed neutron activation analysis for the determination of inorganic impurities in drugs sampled. The results showed that 60% of the samples were unsatisfactory for pharmacopoeial tests. The contents of the capsules sampled for individual testing unit dose uniformity between 0% and 136.2%. This test is important in evaluating the quality, which influences the safety and efficacy of drug treatment, since it allows you to check if the product contains the proper dosage and necessary for successful pharmacotherapy. On the other hand, underdosing can lead to reduced or absent desired therapeutic response, and overdoses can provide an undesirable effects and even toxic. The concentration of inorganic impurities was considered to be relatively small. However, no specific limits for some chemical elements in medicine hamper a better thread. In addition, further studies must be performed to assess chronic exposure to low concentrations of inorganic impurities, since drugs can be continuously used, and other sources of exposure must also be considered in order to evaluate the risk. The problems related to the quality and safety of compounded drugs are still reality in the country and reveal a serious public health problem, especially regarding the lack of uniformity between the unit doses of medications. It is suggested that the competent authorities to sanitary products, propose changes in supervision and improvements in legislation, since the analysis required by the law, are not sufficient to ensure the quality of drugs dispensed in pharmacies. (author)

  20. Evaluation of the effects of gamma radiation on physicochemical characteristics of kiwi (Actinidia deliciosa) cv. Hayward minimally processed; Avaliacao dos efeitos da radiacao gama nas caracteristicas fisico-quimicas de kiwi (Actinidia deliciosa) cv. Hayward minimamente processado

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Ana Claudia Sampaio

    2011-07-01

    The search for a healthy life has led consumers to rethink their eating habits, consuming fruits and vegetables in place of manufactured products, therefore, the demand for minimally processed products has evolved rapidly. The kiwi fruit (Actinidia deliciosa) has high nutritional value, being rich in C vitamin especially, which has wide acceptance in consumer markets. Thus, along with papaya, passion fruit and pineapple, kiwi can be considered as an additional feature of C vitamin in the diet, or as a substitute for traditional citrus. The aim of this study was to assess the effects of gamma radiation on physical and chemical characteristics of kiwis minimally processed and stored under refrigeration, since this technology increases the shelf life of fruits and vegetables. The Kiwis was stripped, processed and cut into slices, stored in polyethylene bags of 10 cm squared and irradiated at doses of 0 (control), 1 and 2 kGy. A source of {sup 60}Co Gammacell 220, dose rate of 0.429 kGy/hour, in which each treatment had 5 replicates with 15 slices of kiwifruit per replicate. After irradiation the samples were stored in a climatic chamber at 6 degree C (near the temperature of commercial refrigerators). The following criteria were physical chemical analysis: pH, color, chlorophyll content, loss of weight, moisture, acidity and Brix. The analysis were done on 1{sup st}, 7{sup th} and 14{sup th} days after irradiation. The results indicated that gamma radiation did not induce deleterious changes in the physicochemical properties of the kiwi may be used for preservation of minimally processed kiwifruit. (author)

  1. Synthesis and chemical modification of polymeric resins for the treatment of cations and aromatic hydrocarbons in produced oily water; Sintese de modificacao quimica de resina polimerica e aplicacao na remocao de cations e hidrocarbonetos aromaticos presentes em agua produzida

    Energy Technology Data Exchange (ETDEWEB)

    Aversa, Thiago M.; Rodrigues, Monique F.; Vieira, Helida V.P.; Queiros, Yure G.C.; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro, Instituto de Macromoleculas, Lab. de Macromoleculas e Coloides na Industria do Petroleo, Rio de Janeiro, RJ (Brazil)], e-mail: thiagoaversa@ima.ufrj.br

    2011-07-01

    The use of chemically modified resins in oily water treatment process is not very developed yet. Because of this, this work suggests to study the styrene and divinylbenzene sulfonation effect on oil and grease, aniline and calcium removal from the water. The aniline, oils and greases belong to a class of toxic organic compounds, with the Brazilian maximum limits established for disposal in CONAMA 393/2007, while the calcium ions belong to the group of cations of alkaline earth metals which improve hardness to the water, may cause fouling as carbonates and sulfates form. By using sulfonated resins in oily water treatment it is possible to remove not only oils and greases but also calcium and aniline. These kinds of polar compounds are removed because of the cation exchange capacity of resin. (author)

  2. Propagation of crevices in stainless steel AISI304L in conditions of hydrogen chemistry (HWC); Propagacion de grietas en acero inoxidable AISI304L en condiciones de quimica de hidrogeno (HWC)

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Fuentes C, P.; Merino C, F. [ININ, 52750 Ocoyoacac, Estado de Mexico (Mexico); Castano M, V. [IFA-UNAM, Juriquilla, Queretaro (Mexico)]. e-mail: ads@nuclear.inin.mx

    2006-07-01

    Crevice growth velocities in samples of AISI 304L stainless steel thermally welded and sensitized were obtained by the Rising displacement method or of growing displacement. It was used a recirculation circuit in where the operation conditions of a BWR type reactor were simulated (temperature of 288 C and a pressure of 8 MPa) with the chemistry modified by the addition of hydrogen with and without the addition of impurities of a powerful oxidizer like the Cu{sup ++} ion. CT pre cracked specimens were used and each rehearsal stayed to one constant displacement velocity of 1 x 10{sup -9} m/s (3.6 {mu}m/hr), making a continuous pursuit of the advance of the crack by the electric potential drop technique. To the end of the rehearsal it was carried out the fractographic analysis of the propagation surfaces. The values of the growth velocities obtained by this methodology went similar to the opposing ones under normal conditions of operation; while the fractographic analysis show the cracks propagation in trans and intergranular ways, evidencing the complexity of the regulator mechanisms of the one IGSCC even under controlled ambient conditions or with mitigation methodologies like the alternative hydrogen chemistry. (Author)

  3. Chemical characterization of xyloglucan obtained from Tamarindus indica seeds from the semi arid northeastern; Caracterizacao quimica de xiloglucana obtida a partir de sementes de Tamarindus indica oriundas do semi arido nordestino

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Delane da C.; Cunha, Arcelina P.; Silva, Sarah M.F.; Gallao, Maria Izabel, E-mail: izagalao@gmail.com [Rede Nordeste de Biotecnologia (RENORBIO), Fortaleza, CE (Brazil). Centro de Ciencia; Azeredo, Henriette M.C. de [EMBRAPA Agroindustria Tropical, Fortaleza, CE (Brazil)

    2013-07-01

    Playing an important role in food, seeds are sources of carbohydrates, proteins and lipids, so they have been explored for a long time by the food industry. For this reason, the objective of present work is to obtain and characterize xyloglucan obtained from tamarind seeds (Tamarindus indica). In order to assess possible industrial applications of the polysaccharide, it was characterized by Infrared Fourier Transform spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) and Thermogravimetric Analysis (TGA). Search results showed that it was possible to perform xyloglucan extraction but the process still requires improvements in order to increase the extraction yield. FTIR, NMR and TGA results were similar to those found in literature. (author)

  4. Chemical characterization of xyloglucan obtained from Tamarindus indica seeds from the semi arid northeastern (Brazil); Caracterizacao quimica de xiloglucana obtida a partir de sementes de tamarindus indica oriundas do semi arido nordestino

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Delane da C.; Cunha, Arcelina P.; Silva, Sarah M.F.; Gallao, Maria Izabel, E-mail: izagalao@gmail.com [Rede Nordeste de Biotecnologia (RENORBIO), Forteleza, CE (Brazil). Centro de Ciencia; Universidade Federal do Ceara (UFC), Fortalea, CE (Brazil); Azeredo, Henriette M.C. de [EMBRAPA Agroindustria Tropical, Fortaleza, CE (Brazil)

    2015-07-01

    Playing an important role in food, seeds are sources of carbohydrates, proteins and lipids, so they have been explored for a long time by the food industry. For this reason, the objective of present work is to obtain and characterize xyloglucan obtained from tamarind seeds (Tamarindus indica). In order to assess possible industrial applications of the polysaccharide, it was characterized by Infrared Fourier Transform spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR) and Thermogravimetric Analysis (TGA). Search results showed that it was possible to perform xyloglucan extraction but the process still requires improvements in order to increase the extraction yield. FTIR, NMR and TGA results were similar to those found in literature. (author)

  5. Physico-chemical quality of drinking water in the northwest area of Madrid (Spain); Calidad fisico-quimica de las aguas de abastecimiento de la zona noroeste de Madrid

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Mata, M.; Orzaez Villanueva, M. T.; Tenorio Sanz, M. D.; Garcia Puertas, P. [Universidad Complutense de Madrid (Spain); Montes Boltella, C. [Universidad Carlos III. Leganes Madrid (Spain)

    2001-07-01

    A physico-chemical analytical study of the edible waters of the northwest area of Madrid has been made. The object was to evaluate the quality characters of this water thought the water analysis of 40 representative buildings. The parameters analyzed were odour, taste, turbidity, pH, conductivity, nitrate, nitrite, ammonia, oxid ability and chlorine. The results show the analyzed waters agree with the current public consume waters legislation through with some punctual exceptions. (Author) 13 refs.

  6. Caracteristicas fisico-quimicas e microbiológicas de ovos de codorna conservados na forma de picles
    Physico-chemical and microbiology of quail eggs preserved in the form of pickles

    Directory of Open Access Journals (Sweden)

    P. B. FARIA

    2010-12-01

    Full Text Available

    Visando aumentar o tempo de conservação, com salga e acidificação do ovo de codorna cozido na forma de picles, foram testados sete tipos de soluções: A (60% vinagre, 8% NaCl; B (40% vinagre, 8% NaCl; C (20% vinagre, 0,3% ácido cítrico, 8% NaCl; D (20% vinagre, 0,3% ácido cítrico, 5% NaCl; E (2% ácido acético, 0,3% ácido cítrico, 5% NaCl,; F (2% ácido acético, 0,3% ácido cítrico, 5% NaCl, 0,02% benzoato de sódio e G (0,4% ácido acético, 0,3% ácido cítrico, 5% NaCl. Foram realizados análises de pH, acidez titulável, cloretos totais e perda de peso dos ovos, nos intervalos de 2, 7, 14, 21, 28 dias. Todos os resultados foram infl uenciados significativamente a partir do segundo dia do início do experimento. Para acidez titulável as soluções A, E e F mostraram maior acidez (p<0,05. No produto, o pH inicial foi reduzido a partir do segundo dia e somente a solução G apresentou valores de pH acima de 4,5. Para cloretos totais, as soluções A, B e C mostraram maior percentual (p<0,01 do que os demais. As conservas promoveram mudanças significativas a partir do segundo dia, as soluções com maiores porcentagens de acidez e menor valores de pH proporcionaram melhor estabilidade e menor desenvolvimento de microrganismos mesófilos. As soluções D, E e F apresentaram em geral melhores características físico-químicas e microbiológicas para conservação de ovos de codorna na forma de picles.

  7. Response function of an HPGe detector simulated through MCNP 4A varying the density and chemical composition of the matrix; Funcion respuesta de un detector HPGe simulada mediante MCNP 4A variando la densidad y composicion quimica de la matriz

    Energy Technology Data Exchange (ETDEWEB)

    Leal A, B.; Mireles G, F.; Quirino T, L.; Pinedo, J.L. [Universidad Autonoma de Zacatecas, Zacatecas (Mexico)]. e-mail: bleal79@yahoo.com.mx

    2005-07-01

    In the area of the Radiological Safety it is required of a calibrated detection system in energy and efficiency for the determination of the concentration in activity in samples that vary in chemical composition and by this in density. The area of Nuclear Engineering requires to find the grade of isotopic enrichment of the uranium of the Sub-critic Nuclear Chicago 9000 Mark. Given the experimental importance that has the determination from the curves of efficiency to the effects of establishing the quantitative results, is appealed to the simulation of the response function of the detector used in the Regional Center of Nuclear Studies inside the range of energy of 80 keV to 1400 keV varying the density of the matrix and the chemical composition by means of the application of the Monte Carlo code MCNP-4A. The obtained results in the simulation of the response function of the detector show a grade of acceptance in the range from 500 to 1400 keV energy, with a smaller percentage discrepancy to 10%, in the range of low energy that its go from 59 to 400 keV, the percentage discrepancy varies from 17% until 30%, which is manifested in the opposing isotopic relationship for 5 fuel rods of the Sub critic nuclear assemble. (Author)

  8. Effect of adding of the styrene-butadiene-styrene (SBS) copolymer in chemical and rheological properties of the brazilian asphalt; Efeito da adicao de SBS nas propriedades quimicas e reologicas de asfalto oriundo de petroleo brasileiro

    Energy Technology Data Exchange (ETDEWEB)

    Lucena, M.C.C.; Soares, S.A. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Quimica Organica e Inorganica]. E-mail: mccl@dqoi.ufc.br; sas@ufc.br; Soares, J.B. [Ceara Univ., Fortaleza, CE (Brazil). Dept. de Engenharia de Transportes]. E-mail: jsoares@det.ufc.br

    2003-07-01

    Chemical and rheological characterization of the asphalt cement (AC) from the Fazenda Alegre petroleum, and the effect of adding 4.5% of the styrene-butadiene-styrene (SBS) copolymer were investigated. Structural characteristics were analyzed by infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). A structure similar to the Arabian and Venezuelan petroleum was observed. The simulated aging led to structural modification noticed by the increment in the carbonyl and sulphoxide groups. Thermogravimetry (TGA) showed that SBS did not affect the AC thermal decomposition at both inert and oxidative atmosphere. However, the differential scanning calorimetry (DSC) showed a decrease in the glass transition temperature of the material when SBS was added. The effect of SBS on the absolute viscosity revealed that SBS is not an inert additive and causes an increase in viscosity, in a nonlinear fashion. The commonly found Newtonian behavior of asphalt binders under high temperatures was also found on the SBS modified binder. Dynamic mechanical tests have shown that SBS increases the binder performance grade. (author)

  9. Physiochemical, energy characteristics and performance of coconut fiber in the sorption of diesel and bio diesel oils; Caracteristicas fisico-quimicas, energetica e desempenho da fibra de coco na sorcao de oleos diesel e biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Adriana Ferla de [Pos-Graduacao em Agronomia - Energia na Agricultura, Faculdade de Ciencias Agronomicas, Universidade Estadual Paulista - FCA/UNESP, Botucatu, SP (Brazil); Curso Superior de Tecnologia em Biocombustiveis, Universidade Federal do Parana - UFPR, Palotina, PR (Brazil)], e-mail: adrianaferla@ufpr.br; Leao, Alcides Lopes [Dept. de Recursos Naturais, Faculdade de Ciencias Agronomicas, Universidade Estadual Paulista - FCA/UNESP, Botucatu, SP (Brazil)], e-mail: alcidesleao@fca.unesp.br; Caraschi, Jose Claudio [Universidade Estadual Paulista - UNESP, Itapeva, SP (Brazil)], e-mail: carachi@itapeva.unesp.br; Oliveira, Luciano Caetano de [Curso de Agronomia, Universidade Federal do Parana - UFPR, Palotina, PR (Brazil)], e-mail: lucianocaetano@ufpr.br; Goncalves, Jose Evaristo [Pos-Graduacao em Agronomia - Energia na Agricultura, Faculdade de Ciencias Agronomicas, Universidade Estadual Paulista - FCA/UNESP, Botucatu, SP (Brazil)], e-mail: evaristto@yahoo.com.br

    2011-07-01

    Accidents involving oil spills and its derivatives on the soil and in hydric bodies are common and worrying once they endanger the quality of the ecosystem. An economical and efficient way of combating oil spills is the use of the sorption method using sorbent materials. There is a range of sorbent materials, however, the natural ones like biomass and vegetable fibers demonstrate interest due to the low cost and good sorbent capacity. There are works concerning the sorption of crude oil, however for diesel and bio diesel, which had their production increased, there is a little or even nothing exists in the literature. The aim of this work was to investigate the sorption capacity of coconut fiber (Cocos nucifera) confronting to the fuels, diesel and biodiesel and to compare them with the peat commercially used. The bio sorbents were also submitted to the physiochemical and energy characterization. Most of the tests were performed on the granulometric size range of {<=}180 {mu}m 180-425 {mu}m; 425-850 {mu}m e 850-3350 {mu}m. The coir fiber presented capacity of diesel and bio diesel sorption similar to the commercial sorbent made of peat. The determination of the calorific power of the bio sorbents shows that they can be used for energy generation before and after they are used as sorbents. This way, those materials can be used after studies of economical viability in this sector and still to increase the economy of the areas where they are abundant. (author)

  10. Evaluation of occupational exposure to chemicals in research and development laboratories in the petrochemical industry; Avaliacao da exposicao ocupacional a substancias quimicas em laboratorios de pesquisa e desenvolvimento na area petroquimica

    Energy Technology Data Exchange (ETDEWEB)

    Rebelo, Paulo Antonio de Paiva [Seguranca, Meio Ambiente, Eficiencia Energetica e Saude (SMES). Gerencia de Saude (Brazil)], e-mail: prebelo@petrobras.com.br; Coeli, Medina [Unidade de Negocio de Exploracao e Producao do Rio de Janeiro (UN-RIO). Gerencia de Seguranca(Brazil)], e-mail: leo.medina@petrobras.com.br; Rosa, Henrique Vicente Della; Nascimento, Elizabeth de Souza [Universidade de Sao Paulo (USP). Faculdade de Ciencias Farmaceuticas (Brazil)], e-mails: hdellarosa@toxikon.com, esnasci@usp.br

    2009-04-15

    A sectional study was conducted on workers in 137 laboratories, 30 pilot units and support areas of a research center in order to evaluate the level of occupational exposure based on environmental measurements from the 2004's workplace environmental protection program with the aim of assessing the risk of health injury arising from occupational exposure to chemical agents. The recognition task was developed using interviews and secondary data from safety programs covering health and environmental risks of all procedures, facilities / equipment and activities. 2,738 cases of exposure were identified, involving exposure to 484 chemicals (with 246 agents and 238 chemicals mixtures), ranging in purity and concentration, found in 243 jobs. The target population comprised 1,563 workers exposed to chemical agents, subdivided into 168 different Homogeneous Group of Expose with an average of 4.55 employees per group. In each workplace were identified, on average, 4.91 HGE and, on average, 3.73 chemicals. Regarding the 2,738 cases of chemical agents versus activity, in 14% of the cases (382 cases) there was daily exposure, in 82.1% (2,249 cases) the frequency of use varied from two to three times a week and in the remaining 3.9% (107 cases) the use was sporadic, about once a week or less. Nine of the ten most frequently used substances were hydrocarbons. 977 samples (485 samples of chemicals and 492 samples of benzene) were measured. Out of the total number of measurements taken, 91.9% of the evaluations corresponding to 92.5% of workers who work with chemicals, presented environmental measurement results below the action level, demonstrating, therefore, exposure to low concentrations.Chemical were found in most areas of work and accounts for 81% of occupational exposure in the evaluated laboratories. There is evidence of presence of one given substance in various locations, as well as of a great diversity of frequently used chemicals, since in every workplace 3.73 chemicals on average were identified, ranging from 1 to 12 and 96.1% of cases. Exposure to a given substance occurs at least every three days; in 14% of cases it happens on a daily basis, involving 71.5% of chemicals. In the study group, 59% of workers remain in business for over ten years, undergoing exposure for a long time (chronic). (author)

  11. Recent trends in the mitigation of the IGSCC through modifications in the water chemistry of BWR reactors; Tendencias recientes en la mitigacion del IGSCC mediante modificaciones en la quimica del agua de reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Robles, E.F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    During the last years, the Nuclear Power stations had been that to adequate or to modify the parameters and operational conditions, attempting to maintain and to safeguard the integrity and functionality of its components and systems, as well as the personnel safety involved in its operation. In a Boiling water reactor (BWR), the chemical control of the water, constitutes one of the fundamental aspects to get a sure and reliable operation, having as main objectives: (a) The protection of the reactor vessel, of the structural materials of the same one and of the pipes and components of those recirculation systems against the Intergranular stress corrosion phenomena (IGSCC); (b) To guarantee the integrity of the nuclear fuel minimizing the corrosion phenomena in the fuel elements; and (c) The reduction of the operational dose of the personnel involved directly in the operation and maintenance by means of the control of the activated corrosion products. (Author)

  12. Características físico-quimicas, análise sensorial e conservação de frutos de cultivares de bananeira resistentes à sigatoca-negra

    Directory of Open Access Journals (Sweden)

    Célia Lúcia Siqueira

    2010-10-01

    Full Text Available O cultivar Prata Anã é o mais plantada no Norte de Minas Gerais, o que demonstra estar a bananicultura regional baseada numa variedade suscetível à sigatoca-negra. Apesar de existirem cultivares resistentes em fase de recomendação para o cultivo na região, ainda são escassos os trabalhos relacionados a metodologias de conservação pós-colheita. Assim, o objetivo deste trabalho foi avaliar o período de armazenamento e as características físico-químicas e sensoriais dos cultivares de bananeira Fhia - 02 e Precioso, ambos resistentes à sigatoca-negra, e o efeito da atmosfera modificada associada à refrigeração. Foram realizados três experimentos, o primeiro em temperatura ambiente, o segundo a 12 ºC e o terceiro a 15 ºC. Esses experimentos foram instalados no delineamento em blocos casualizados em esquema de parcelas subdivididas no tempo, tendo nas parcelas um fatorial 2 (com e sem embalagem x 2 (Fhia - 02 e Precioso e nas subparcelas as avaliações em intervalo de seis e dois dias para frutos armazenados nas temperaturas de 12, 15 e 25 ºC, com quatro repetições e três frutos por unidade experimental. Após o tratamento, os frutos foram dispostos em bandejas de poliestireno expandido (sem embalagem e embalagens de 10 e 16 µm e umidade relativa de 90%. As características avaliadas foram: tamanho, diâmetro, cor, firmeza, perda de matéria fresca, sólidos solúveis totais (SST, acidez total titulável (ATT, SST/ATT, pH e análise sensorial. O uso da embalagem associada à refrigeração permitiu armazenar os frutos por 28 dias, mantendo as características físico-químicas.

  13. Influence of the chemical composition, heat and surface treatment in the biofouling of austenitic stainless steels; Influencia de la composicion quimica, del tratamiento termico y del acabado supreficial en el bioensuciamiento de aceros inoxidables austeniticos

    Energy Technology Data Exchange (ETDEWEB)

    Sarro, M. I.; Aleman, O.; Moreno, D. A.; Roso, M.; Ranninger, C.

    2004-07-01

    The main objective of this study was to analyse the biofouling processes in the kinds of stainless steels used normally in industry (UNS S30400, UNS S30403 and UNS S31600), with different surface treatments after grinding and polishing. The study was developed using two microscopy techniques. Scanning Electron Microscopy (SEM) was used to evaluate the microorganisms distribution in the materials, and Epi fluorescence Microscopy was used to evaluate the viability of cells in the biofilm. The results revealed the influence of the material, heat treatment, surface treatment and roughness in the biofouling processes in the stainless steel assays. (Author) 33 refs.

  14. Synthesis of poly(D,L-lactide-co-glycolide) copolymers and its chemical characterization by NMR and FTIR; Sintese e caracterizacao quimica por RMN e FTIR do copolimero poli(D,L-lactideo-co-glicolideo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Poly(D,L-lactide-co-glycolide) copolymer is of great interest for medical applications. This interest is justified by the fact that it is bioreabsorbable, biocompatible and non-toxic, while its degradation kinetics can be modified by the copolymerization ratio of the monomers. In this study, copolymers were synthesized at 175 deg C by opening the rings of the cyclic dimers of the D,L-lactide and glycolide monomers in the presence of stannous octoate initiator and lauryl alcohol co-initiator. The efficient application of a vacuum to the reaction medium, coupled with adequate stirring, is fundamental for the success of the synthesis. The following analysis techniques were used to characterize the synthesized copolymers: Nuclear Magnetic Resonance Spectroscopy (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). The chemical composition and the ratio of the monomers in the synthesized copolymer were determined. (author)

  15. Applications of artificial intelligence techniques to organic chemistry. Study on sup 13 C NMR of steroids using computer. Aplicacoes de tecnicas de inteligencia artificial em quimica organica. Estudo, por computador, de RMN sup 13 C de esteroides

    Energy Technology Data Exchange (ETDEWEB)

    Lins, A P [Instituto Biologico, Sao Paulo, SP (Brazil). Secao de Farmacologia; Furlan, M [UNESP, Araraquara, SP (Brazil). Inst. de Quimica; Gastmans, G P [UNESP, Guaratingueta, SP (Brazil). Inst. de Quimica e Fisica; Emerenciano, V P [Sao Paulo Univ., SP (Brazil). Inst. de Quimica

    1991-01-01

    This work describes the utilization of two groups of programs in searching for characteristic signals of NMR {sup 13}C steroidal compounds. The first group of programs used data bases with the spectral data and a methodology that enables the choice and the search of substructures. The chemical shifts and multiplicities for each specific substructure are used as rules to identify different types and subtypes of steroidal compounds. The second one was built to apply the rules formulated by the first group of programs and to foresee any skeletal based on a spectral analysis. (author).

  16. Chemical structures and thermal properties of polyesters obtained from different samples of bio diesel epoxidized; Estruturas quimicas e propriedades termicas de poliesteres obtidos a partir de diferentes tipos de biodiesel epoxidado

    Energy Technology Data Exchange (ETDEWEB)

    Samios, Dimitrios; Reiznautt, Quelen B.; Nicolau, Aline; Martini, Denise D.; Chagas, Arthur L. das, E-mail: dsamios@iq.ufrgs.b [Universidade Federal do Rio Grande do Sul (IQ/UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica. Lab. de Instrumentacao e Dinamica Molecular

    2009-07-01

    In this work new structures from oligo esters and polyesters from different oils (olive oil, sunflower oil and linseed oil) were synthesized and characterized. Oligo esters and polyesters were synthesized from the reaction of fatty acid methyl epoxy-esters, obtained from different oils, with cis-1,2-cyclohexanedicarboxylic anhydride in the presence of triethylamine (TEA). Different amounts of the resin 1,4-butanediol diglycidyl ether (BDGE) were added in order to increase the capacity of crosslinking. The molar ratio of BDGE used in system was between 0 and 0.066. The intermediate structures, as well as the oligo esters and polyesters produced, were analyzed by using Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance ({sup 1}H - NMR). The thermal behavior of the products was realized through differential scanning calorimetry and Thermogravimetric analyses. The presence of BDGE in the materials chains increases the bonding capacity resulting in a higher molecular weight material which presents good thermal stability. (author)

  17. Physical, chemical and mineralogical characterization of water treatment plant waste for use in soil-cement brick; Caracterizacao fisica, quimica e mineralogica de residuo de estacao de tratamento de aguas para aproveitamento em tijolo solo-cimento

    Energy Technology Data Exchange (ETDEWEB)

    Pessin, L.R.; Destefani, A.Z.; Holanda, J.N.F., E-mail: larapessin@hotmail.com [Universidade Estadual do Norte Fluminense Darcy Ribeiro (CCT/PPGECM/UENF), Campos dos Goytacazes, RJ (Brazil)

    2011-07-01

    The water treatment plants (WTP) for human consumption generate huge amounts of waste in the form of sludge (sludge) that have been over the years mostly inadequately prepared in water resources and the environment. Moreover, traditional methods of disposal of waste water treatment plants commonly used are generally costly activities. An alternative method for disposal of this waste abundant is its incorporation in ceramic products. This work is focused on the physical-chemical and mineralogical composition of a sample of waste water treatment plants from the region of Campos dos Goytacazes-RJ to their use in the manufacture of soil-cement brick. Several characterization techniques were used including X-ray diffraction, X-ray fluorescence, scanning electron microscopy, picnometry, particle size analysis and plasticity. The experimental results indicate that the waste water treatment plants have the potential to be used in the manufacture of ecologic soil-cement bricks. (author)

  18. Chemical signature study of tupiguarani ceramic tradition from Central region of the Rio Grande do Sul state, Brazil; Estudo de assinaturas quimicas em ceramica da tradicao tupiguarani da regiao central do estado do Rio Grande do Sul, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Bona, Irene Akemy Tomiyoshi

    2006-07-01

    In this work a model based on experimental results using chemical composition data of the pottery sherds applied to Spearmann's no parametric test, principal component analysis and discriminant analysis, was applied. The samples are soils and Tupiguarani Tradition pottery sherd from the central area of the Rio Grande do Sul State. The chemical elements , Al, Ba, Ca, Cr, Fe, K Mn, Pb, Rb, S, Si, Sr, Ti, V and Zn were determined by energy dispersive X-ray fluorescence (EDXFR) while Ce, Cu, Gd, La, Nd, Pr, Sm, Th and Y by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) techniques. Relationships among the pottery characteristics, studied sites and sherd dispersion in the several sites were proposed. Indications of chemical signature of the small pottery with function to go or not to the fire were observed. The largest dispersion is of small pottery with surface treatment no corrugated. The potteries chemical fingerprints from Ijui River, Ibicui-Vacacai Mirim River and Jacui River were verified. (author)

  19. Identification and analysis of the environmental management documentation related to the activities of environmental and chemical analysis laboratories; Identificacao e analise da documentacao pertinente a gestao ambiental relacionada as atividades de laboratorios de analises quimicas e ambientais

    Energy Technology Data Exchange (ETDEWEB)

    Otomo, Juliana Ikebe; Brandalise, Michele; Romano, Renato Lahos; Marques, Roberto; Szarota, Rosa Maria; Raduan, Rosane Napolitano; Salvetti, Tereza Cristina; Egute, Nayara dos Santos; Almeida, Josimar Ribeiro de; Aquino, Afonso Rodrigues de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: araquino@ipen.br

    2009-08-15

    In the last years, many documents were elaborated by several countries and entities, concerning the environmental question. The implantation of and Environmental Management System requires specific documentation so that a company or laboratory can adjust themselves to the environmental quality. For laboratories of chemical, environmental analyses and also nuclear materials, the needs of attendance to the requirements of the following municipal, state and federal institutions were identified: Corpo de Bombeiros, CNEN - Comissao Nacional de Energia Nuclear, IBAMA - Instituto Brasileiro do Meio Ambiente e dos Recursos Renovaveis, ANVISA - Agencia Nacional de Vigilancia Sanitaria, PMSP - Prefeitura Municipal de Sao Paulo e a CETESB - Companhia Ambiental do Estado de Sao Paulo. (author)

  20. Quality in the chemical analysis of biological matrices by fluorescence X-ray by energy dispersive; Qualidade nas analises quimicas de matrizes biologicas pela fluorescencia de raios-X por dispersao de energia

    Energy Technology Data Exchange (ETDEWEB)

    Sousa, Evely E. de; Paiva, Jose Daniel S. de; Franca, Elvis J. de; Almeida, Macio E.S.; Cantinha, Rebeca S.; Hazin, Clovis A., E-mail: evelysousa_182@hotmail.com, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

    2013-07-01

    The aim of this study was to obtain multielement analytical curves of high analytical rigor to the analysis of biological matrices by the technique of fluorescence x-ray energy dispersive - EDXRF. Calibration curves were constructed from the reference materials IAEA 140, IAEA 155, IAEA V8, V10 to the International Atomic Energy Agency - IAEA, and SRM1515, SRM 1547, SRM 1570a, SRM 1573a, SEM 1567a, to the National Institute of Standards and Technology - NIST. After energy calibration, all samples were subjected to vacuum to the analyzes by 100 seconds for each group of chemical elements. The voltages used were respectively 15 keV for chemical elements with less than atomic number 22 and 50 keV for the others. After the construction of the curves, the analytical quality was assessed by the analysis of a portion-test of the reference material SRM 2976, also produced by NIST. Based on the number of certified reference materials used for construction of calibration curves in this work, quality analytical protocol was originated with considerable reliability for quantification of chemical elements in biological samples by EDXR.

  1. Effect of the gamma radiation on the chemical, rheological, baker and microbiological properties in wheat flour; Efecto de la radiacion gama sobre las propiedades quimicas, reologicas, panaderas y microbiologicas en harina de trigo

    Energy Technology Data Exchange (ETDEWEB)

    Agundez A, Z; Fernandez R, M V [Departamento de Ciencias Quimico Biologicas, Universidad de Sonora, Hermosillo (Mexico); Arce C, M E; Cruz Z, E [Instituto de Ciencias Nucleares, UNAM, 04510 Mexico D.F. (Mexico); Chernov, V; Barboza F, M [Departamento de Investigacion en Fisica, Universidad de Sonora, Hermosillo (Mexico)

    2002-07-01

    The gamma radiation has been used in several places of the World as a sterilization method, preservation and pasteurization of foodstuffs, effect which is achieved due to diminishing or elimination of the microorganisms, reaching every time more acceptance, moreover eliminates the uses of toxic and carcinogenic substances, of general use, but at the present, being in the process of being totally prohibited, due to the higher risk in the human health. In this work the related results with the effects of the gamma radiation are presented, coming from a {sup 60} Co source, in commercial wheat flour exposed to a dose of 1.0 KGy. The used dose is that allowed according to the NOM-033-SSA1-1993 standard. It was determined that the chemical characteristics of humidity, protein and ashes were not affected by radiation. The rheological properties neither suffer severe effects as consequence of radiation; the pharynographic and alveographic parameters were lightly affected by the treatment. Significant changes were detected in the percentage of water absorption and in the tolerance index to mixing. However a diminish of 10% in the development time and an increase of 13% in the stability was observed, for the irradiated samples respect to the those samples not irradiated. In relation to the alveograph parameters it was only detected a diminish of 7% in the force parameter (w) without changes in the tenacity/blowing up index ratio (P/L). The fall number diminish 11% indicating a small diminution in viscosity. The bakering properties do not turn out modified by the irradiation treatment finding a specific weight of 4.6 and 4.5 (cm{sup 3}/g) for the control and irradiated samples, respectively. In the mesophyll analysis it was found a diminish of 96% from the original charge in control samples, observing a diminution of 74 and 25% in yeasts and mushrooms respectively. Microbiologically it was determined absence of total coliforms bacteria and faecal coliforms in the control samples and of course in those ones treated with gamma radiation. In general the results show that the use of gamma radiation in the recommended dose does not affect significantly the functional properties of the wheat flour, being moreover advantageous due to the diminution of the bacterial charge induced by the gamma radiation. Acknowledgments. Project sponsored by the UNAM, DGICSA-SEP and CONACYT. (Author)

  2. Study of clay chemical composition in formation of new phases in crystalline materials ceramic; Estudo da composicao quimica de argilas na formacao de novas fases cristalinas em materiais ceramicos

    Energy Technology Data Exchange (ETDEWEB)

    Lima, L.K.S.; Goncalves, W.P.; Silva, V.J.; Dias, G.; Neves, G.A.; Santana, L.N.L., E-mail: lizandralima15@gmail.com, E-mail: lisiane@dema.ufcg.edu.br [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia dos Materiais

    2016-07-01

    The knowledge of the characteristics of raw materials and the behavior of these during the heat treatment is crucial before starting any manufacturing process of clay-based products. The objective of this work was to study phase transformations of clay under different heat treatments using conventional oven. To achieve the same were used two clays coming from the municipality of Cubati - PB and kaolin from an industry in the Northeast. The samples were subjected to beneficiation process, crushing, grinding and sieving and further characterized: chemical analysis, particle size, thermal and mineralogical. For heat treatment temperatures employed were 1000, 1100 and 1200 ° C, heating rate 5 ° C / min and residence time of 60min. After this step, the mineralogical characterization was performed by x-ray diffraction technique. Clays with larger particle size fraction below 2um and greater amount of flux oxides showed higher amount of mullite for the temperatures studied. The results also showed nucleation of mullite phase from 1100 °C, a band 2theta in the range of between 20 and 25°, characteristic of amorphous silica and the temperature rise was observed intensification of crystalline phases. (author)

  3. Effect of endogenous factors on the chemical perception of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) to sex pheromone; Efeito de fatores endogenos na percepcao quimica de Grapholita molesta(Busck) (Lepidoptera: Tortricidae) ao feromonio sexual

    Energy Technology Data Exchange (ETDEWEB)

    Altafini, Deisi L.; Sant' Ana, Josue; Redaelli, Luiza R., E-mail: deisila@gmail.co [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Dept. de Fitossanidade. Programa de Pos-Graduacao em Fitotecnia

    2010-06-15

    The oriental fruit moth, Grapholita molesta (Busck), stands out as one of the most important pest in Rosaceae orchards in Brazil. During feeding, caterpillars bore into shoots, branches and fruits, impairing the commercial production. This work aimed to study the effect of endogenous factors in the chemical perception and in the species chemotactic behavior, seeking to optimize monitoring and the behavioral control of this pest. We evaluated male electroantennographical (EAG) and chemotactical (olfactometry) responses to the synthetic sex pheromone in different ages, virgins or mated and fed or unfed. The EAG responses of males did not differ for all evaluated factors. Nevertheless, the chemotactical behavior of males seems to decrease with age, not varying as a function of mating or feeding conditions. The knowledge about the interference of these factors in G. molesta may help with the interpretation of fi eld results, allowing the development of suitable and reliable control measures based on infochemicals for behavioral control. (author)

  4. Physicochemical characterization of sludge obtained in a UASB reactor: influence on the energetic utilization in the pyrolysis process; Caracterizacao fisico-quimica de lodo obtido em um reator UASB: influencia no aproveitamento energetico em processo de pirolise

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Murillo Barros de [Universidade Federal do Tocantins (UFT), Palmas, TO (Brazil)], Email: murillopur@yahoo.com.br; Vieira, Glaucia Eliza Gama; Cardoso, Aderlanio da Silva; Silveira, Dyego Amaral; Figueiredo, Radson Lima [Universidade Federal do Tocantins (LEDBIO/UFT), Palmas, TO (Brazil). Lab. de Ensaios e Desenvolvimento de Biomassas e Biocombustiveis

    2010-07-01

    In biological treatment processes of domestic sewer it leaves of the organic matter is converted and another is absorbed being part of the microbial biomass denominated generic of mud biological or secondary composed mainly of biological solids, and that for that reason can also be denominated of sewage sludge. To give a maintainable final destiny for that residue has been one of the great challenges of the sanitation in the last years. Great part of that material is destined unproductive some are incinerated, others are disposed in sanitary embankments. This work had as objective the physiochemical characterization of the digested sludge, virgin and free from oxide of calcium (CaO), produced in the reactor UASB, of ETE Vila Uniao located in the city of Palmas-TO, for the destination as raw material for energy use in pyrolysis process. The collected sample was taken drought and stabilized to be analyzed at the laboratory LEDBIO/UFT where they were studied the particle, tenor of ashes, humidity and volatile density and sequential extraction for soxhlet. Found in the biomass loud tenor of volatile (56,72%), carbon fastens low (5,21%) and a considerable tenor of ashes (32,78%), what suggests that that sludge, in agreement with the comparisons of the literature, can obtain good incomes in pyrolysis process, especially incomes in bio-oil and coal. (author)

  5. Chemical characterization of bottom ashes generated during combustion of a Colombian mineral coal in a thermal power plant; Caracterizacao quimica das cinzas de fundo originadas pela combustao, em usina termoeletrica, de um carvao mineral do nordeste da Colombia

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, H.S.; Nogueira, R.E.F.Q.; Lobo, C.J.S.; Nobre, A.I.S.; Sales, J.C.; Silva, C.J.M., E-mail: hspfisica@hotmail.com [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Centro de Tecnologia. Dept. de Engenharia Metalurgica e de Materiais

    2012-07-01

    Bottom ashes generated during combustion of a mineral coal from Colombia were characterized by X-ray fluorescence spectrometry and X-ray diffraction. The interest in this particular coal is due to the fact that it will be used by a thermal power plant in Ceara, Northeastern Brazil, where it could produce over 900 tons of different residues/combustion products every day. Results from Xray fluorescence allowed identification and quantification of elements present in the sample: silicon (59,17%), aluminum (13,17%), iron (10,74%), potassium (6,11%), titanium (2,91%), calcium (4,97%), sulphur (0,84%) and others (2,09%). The X-ray diffraction revealed patterns from silica, mullite, calcium sulphate and hydrated sodium. Results obtained so far indicate that the material is a potential raw-material for use in the formulation of ceramic components (author)

  6. Determination of concentration of radon, volatile organic compounds (VOC) and water chemistry in springs near to Popocatepetl volcano; Determinacion de la concentracion de radon, VOCs y Quimica del agua en manantiales cercanos al volcan Popocatepetl

    Energy Technology Data Exchange (ETDEWEB)

    Pena, P.; Segovia, N.; Lopez M, B.E.; Cisniega, G. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Valdes, C.; Armienta, M.A.; Mena, M. [Instituto de Geofisica, UNAM, 04510 Mexico D.F. (Mexico)

    2004-07-01

    Popocatepetl volcano is a high-risk active volcano in Central Mexico where the highest population density in the country is settled. Radon in the soil and groundwater together with water chemistry from samples of nearby springs is analysed as a function of the 2002-2003 volcanic activity. Soil radon indicated fluctuations related both the meteorological parameters and sporadic explosive events. Groundwater radon showed essentially differences in concentration due to the specific characteristics of the studied springs. Water chemistry showed stability along the monitoring period indicating also differences between springs. No anthropogenic pollution from volatile organic compounds was observed. (Author)

  7. E-waste: development of recycling process and chemical characterization of circuit printed - motherboard; Lixo eletronico: desenvolvimento de processo de reciclagem e caracterizacao quimica de placa de circuito impresso - motherboard

    Energy Technology Data Exchange (ETDEWEB)

    Junior, O.L.F.; Vargas, R.A.; Andreoli, M.; Martinelli, J.R.; Seo, E.S.M., E-mail: olfjunior@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The electro-electronic industry has been regulated by the National Politic of Solid Residues Act (PNRS) and Bill no. 7.404, concerning the actions, procedures, and method to collect, recycle and promotion of environmentally acceptable final destination of residues. The present work contributes to develop recycling process of printed circuit used in microcomputers and in its chemical characterization. The experimental procedure consisted of grinding, classification, magnetic and electrostatic separation, and separation based on density difference, followed by chemical characterization of the metallic and non metallic materials in the motherboard. It was determined that the amounts of Ag, Al, Ba, Cl, Cr, Cu, Fe, Mn, Pb, and Zn in the residue are above the toxicity allowable levels, and they are in the samples of the decanted material. Among the samples of the floating material, Al, Ba, Br, Ca, Cu, Fe, Pb (in less quantity), Si (in more quantity), and Sn, Ti and Zn were detected. Those materials can be useful in the preparation of red ceramics. (author)

  8. COMPOSICIÓN QUIMICA DE LA LECHE, DIGESTIBILIDAD in vitro DE LA MATERIA SECA Y PRODUCCIÓN EN VACAS ALIMENTADAS CON GRAMÍNEAS SOLAS O ASOCIADAS CON Lotus uliginosus

    Directory of Open Access Journals (Sweden)

    A. Morales

    2013-01-01

    Full Text Available La presente investigación tuvo como objetivo evaluar el uso de la leguminosa Lotus uliginosus como alternativa de inclusión dentro de las praderas en dos ecorregiones estratégicas de la sabana de Bogotá. en cada finca se evaluaron cuatro tratamientos: 1 kikuyo solo (P. clandestinum, 2 kikuyo asociado con trébol pata de pájaro ( P.clandes-tinum + L. uliginosus, 3 festuca alta sola (F. arundinacea y 4 Festuca alta asociada con trébol pata de pájaro (F. arundinacea + L. uliginosus. el número de bovinos varió de acuerdo a la capacidad de carga de cada finca. se utilizaron animales que se encontraban en el segundo tercio de lactancia durante un período experimental de siete días. en cada tratamiento se determinó la producción (L/día y calidad de leche (% de grasa, proteína y sólidos totales; en la pastura se evaluó la composición química (Ms, Fdn, Fda y la digestibilidad in vitro de la materia seca (divMs. se midió el consumo voluntario. en la finca Megaleche la producción de biomasa presentó diferencias significativas (P<0,05 entre los tratamientos destacándose el tratamiento del kikuyo solo; la calidad nutricional de las pasturas también presentó diferencias (P<0,04 destacándose el tratamiento de kikuyo + trébol pata de pájaro, asociación que también se destacó en consumo voluntario (P< 0.05 y producción de leche (P<0,05. en la finca Colega el contenido de proteína del forraje presentó diferencias cuando las gramíneas se asociaron con el trébol pata de pájaro (P<0,001. se concluyó que la introducción del Lotus en las praderas mejoró la producción de leche y consumo de materia seca en los animales.

  9. The influence of chemical composition and fineness on the performance of alkali activated cements obtained from blast furnace slags; A influencia da composicao quimica e da finura no desempenho de cimentos alcali ativados obtidos com escorias de alto forno

    Energy Technology Data Exchange (ETDEWEB)

    Langaro, Eloise Aparecida; Matoski, Adalberto, E-mail: elolangaro@hotmail.com, E-mail: adalberto@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba (Brazil); Luz, Caroline Angulski da; Buth, Islas Stein; Moraes, Maryah Costa de; Pereira Filho, Jose Ilo, E-mail: angulski@utfpr.edu.br, E-mail: islas_sb@hotmail.com, E-mail: maryah_moraes@hotmail.com, E-mail: ilofilho@yahoo.com.br [Universidade Tecnologica Federal do Parana (UTFPR), Pato Branco, PR (Brazil)

    2017-01-15

    New binders are being developed for concrete in order to reduce the environmental impact mainly related to CO{sub 2} emissions. Alkali -activated cements (CATs) are obtained from lime-aluminosilicate materials and an alkali activator and can reduce by 80% the emission of CO{sub 2} compared to Portland Cement (PC). Papers have also shown physical and mechanical properties similar or higher than those presented by the PC, however, the activation of raw material is complex. Recent papers have also have showed a strong influence of the characteristics of raw material on the performance of CAT, however, little mentioned in the literature.. Therefore, this paper aimed to analyze the influence of characteristics of blast furnace slag (fineness and chemical composition) on the behavior of activated alkali cements. For this purpose, two slags were used, A and B, which were submitted to different milling times; and activated using 5% of NaOH. Mortars and pastes were prepared for compressive strength testing (7 and 28 days), measurements of heat of hydration and investigation of microstructure (XRD and DSC) were made. The results showed that the mortar made with slag A reached a very good mechanical performance, close to 48MPa at 28 days, and higher formation of CSH, in opposite of slag B. The probable hypothesis of this study is that the system formed in CAT made with slag A (containing more Al{sub 2}O{sub 3}) could provide CSH with a greater incorporation of Al and a lower crystallinity, increasing the mechanical strength. (author)

  10. Effects of chemical composition and test parameters on the hot ductility of C-Mn-Al steels; Efeito da composicao quimica e parametros de ensaios sobre a ductilidade a quente de acos C-Mn-Al

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Marcelo C.S. de; Comineli, Osvaldo G; Pancieri, Jose G.P.; Oliveira, Maria A.L. de [Espirito Santo Univ., Vitoria, ES (Brazil). Dept. de Engenharia Mecanica; Souza Lima Cardoso, Geraldo I. de [Companhia Siderurgica de Tubarao (CST), Serra, ES (Brazil); Mintz, Barry [The City Univ., London (United Kingdom)

    1987-12-31

    The effects of Al content, as well as hot tensile test parameters on hot ductility of two C-Mn-Al steels are presented. Thermal cycle were carried out to study the influence of thermal oscillations during those compositions cooling, consisting of heating the samples up to a solubilization temperature, high enough to dissolve any phase which could possibly be present in the original ingot, and also to produce a coarser grain size. After 5 minutes at 1330 deg C, the steels were cooled in three different ways to reach test temperature and samples remain at this temperature for 5 minutes for stabilization before testing. Further, a preliminary comparison between hot ductility results, obtained when samples are molten and continuously cooled at two different rates, and those obtained for solution treated samples which are cooled at an intermediate cooling rate. For the two composition solution treated, a ductility was observed trough displaced from each other about 50 deg C, being the Al content the responsible for this difference. (author) 14 refs., 11 figs., 1 tab.

  11. In vitro evaluation of the chemical and morphological changes of the enamel surface using different bleaching techniques; Avaliacao in vitro das alteracoes quimica e morfologica da superficie do esmalte utilizando diferentes tecnicas de clareamento dental

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, Alessandra de Siervi

    2003-07-01

    'In vitro' evaluation through MEV and EDS of the morphological and chemical changes, respectively, of the bovine enamel, submitted to different bleaching techniques. For the MEV evaluation eighteen apical thirds were pigmented and divided into two parts. One half of each sample was the control and the other half was bleached according to the protocol of each test group (n= 6). Group I - home bleaching with a 10% carbamide peroxide; group II bleaching with 35% hydrogen peroxide and LED; group III - bleaching with 35% hydrogen peroxide with diode laser bleaching. The same procedure was done with the eighteen samples which were analyzed through EDS and which had their buccal surface grinded and polished before the bleaching procedure in order to obtain more precise values of the fraction of calcium and phosphorus. The results showed no morphological changes among the analyzed control halves and the bleached halves. There was not a statistical significant difference about Ca and P values, among the control halves and the bleached halves regarding the chemical components (p< 0,05). (author)

  12. Study of the influences of the zeolites physical and chemical characteristics in the soya oil cracking; Estudo das influencias das caracteristicas fisico-quimicas de zeolitas no craqueamento do oleo de soja

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Frances Regiane dos

    1995-10-01

    Vegetable oils have been studied as raw materials to yield fuel hydrocarbons. The catalytic and thermal transformations of these oils have been presented as being able to generate hydrocarbons from which diesel oil and vegetable gasoline may be obtained. (author)

  13. Chemometrics application in fuel's MTR type chemical characterization by X-ray fluorescence; Aplicacao da quimiometria para caracterizacao quimica de combustiveis tipo MTR por fluorescencia de raios-X

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Clayton Pereira da

    2012-07-01

    In Brazil and worldwide the nuclear power has occupied a prominent position with many applications in industry, power generation, environment and medicine, improving the quality of tests and treatments, therefore people's lives. Uranium is the main element used in nuclear facilities and it s employed as base material to generation of electricity in the manufacture of radiopharmaceuticals. In the '50s, during the Cold War, the then newly created International Atomic Energy Agency proposed to oversee nuclear facilities and encourage the manufacture of nuclear fuels with low-enriched uranium (LEU) fuel came then type Material Test Reactor (MTR), manufactured initially in U{sub 3}O{sub 8} and U{sub 3}Si{sub 2} later, both dispersed in aluminum. The use of this technology requires a constant improvement of all processes involving the manufacture of MTR subject to several international protocols, which seek to ensure the reliability of the fuel from the standpoint of practical and environmental. In this context, the control of impurities, from the point of view of neutron economy, directly affects the quality of any nuclear fuel, so strict control is necessary. The literature has reported procedures which, beyond generating residues, are lengthy and costly, they need calibration curve and consequently reference materials. The aim of this work is to establish and validate a methodology for nondestructive quantitative chemical analysis, low cost and analysis time, as well as minimize the generation of waste, for multielement determination of major constituents (Utotal and Si) and impurities (B, Mg, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd and others) present in U3O8 and U{sub 3}Si{sub 2}, meeting the needs of nuclear reactors in the nuclear fuel qualification type MTR. For that purposes, will be applied the X-ray fluorescence technique which allows fast chemical and nondestructive analysis, aside from sample preparation procedures that do not require previous chemical treatments (dissolving, digesting, and others). To corrections like effects of spectral and matrix were applied and evaluated the fundamental parameter method, univariate calibration curve and multivariate calibration. The results were compared by means of statistical tests in accordance with ISO 17025 in MRCs (123 (1-7) and 124 (1-7)) MCRs of U{sub 3}O{sub 8} from New Brunswick Laboratory (NBL) and 16 U{sub 3}Si{sub 2} samples provided by CC of IPEN/CNEN-SP. The chemometrics is a promising method to determination of minor and major constituents on the U3Si2 and U3O8 basis nuclear fuel, because the precision and accuracy are statistically equal volumetric analysis, gravimetric and ICPOES methods. (author)

  14. Cement for oil well developed from ordinary cement: characterization physical, chemical and mineralogical; Cimento para poco de petroleo desenvolvido a partir de cimento comum: caracterizacao fisica, quimica e mineralogica

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, D.N.S.; Neves, G. de A.; Chaves, A.C.; Mendonca, A.M.G.D.; Lima, M.S. de [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Bezerra, U.T., E-mail: daninascimento.eng@gmail.com [Instituto Federal de Educacao, Ciencia e Tecnologia da Paraiba (IFPB), Campina Grande, PB (Brazil)

    2012-07-01

    This work aims to characterize a new type of cement produced from the mixture of ordinary Portland cement, which can be used as an option in the cementing of oil wells. To enable this work we used the method of lineal programming for the new cement composition, then conducted tests to characterize through particle size analysis by laser diffraction, chemical analysis by EDX, TGA, X-ray diffraction, time grip, resistance to compression. The overall result showed that the new cement had made low-C3A, takes more time to the CPP, thermal stability up to 500 ° C, the kinetics of hydration and low levels of major components consistent with the specifications of ABNT. (author)

  15. Chemical and mineralogical characterization of two commercial cements and its evolution in function of time; Caracterizacion quimica y mineralogica de dos cementos comerciales y su evolucion en funcion del tiempo

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez B, O.

    2014-07-01

    Mineralogical evolution of Portland cement is studied during hydration process using materials characterization techniques as X-ray diffraction (XRD) and scanning electron microscopy (Sem) in order to analyze the changes in the various cement minerals as alite, belite, celite, during processing to the hydrated phases of tobermorite gel, portlandite and ettringite, respectively, in the cement paste setting at different ages (3, 7 and 28 days). It was found that the hydration process occurs differently in each mineral because of their reaction rates or changes they experience in their crystals during processing of anhydrous to hydrated phase. You may notice changes in the appearance of the dough as you go hydration and the formation of tobermorite gel, portlandite and ettringite. (Author)

  16. Propositions of new correlations for prediction of physical-chemical properties in products of Brazilian crude oil; Proposicao de novas correlacoes para calculo de propriedades fisico-quimicas de derivados de petroleos brasileiros

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Ulysses Brandao [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2008-07-01

    The prediction of products properties is a useful tool in the petroleum industry, because it allows the estimation of quality when it is not possible to be determined it in the laboratory. Among existing correlations for properties prediction, the best known are those from the American Petroleum Institute (API), but there are limitations in the use of such models to estimate the properties of Brazilian petroleum products. A study was done to determine new correlations which would adjust to these oils. In this work a statistical treatment was used in a group of samples covering products from oils produced in several regions of Brazil. The results of this study are presented in this work. New correlations are proposed to estimate the aniline point, pour point and cloud point of Brazilian oil products. The data are showed graphically, with the experimental values plotted against the results of both the proposed and the API correlations. The average absolute deviations obtained for these correlations were smaller than those presented by the API equations, for the same data sets. This work helps to improve the quality estimation of Brazilian petroleum products using process simulators. (author)

  17. Physicochemical, rheological, thermal, and bread making properties of flour obtained from irradiated wheat;Propriedades fisico-quimicas, reologicas, entalpicas e de panificacao da farinha obtida de trigo irradiado

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Carolina Sobral

    2006-07-01

    Most of the methods that are nowadays used for food preservation derive from old times. Besides these methods, new non-thermal methods have been developed in order to improve food quality during its processing. Irradiation technology has a great contribution potential to improve preservation, storage and distribution of foods. Several studies from international literature have reported the efficiency of irradiation process on microbiological control of grains and their products. Due to the low technological quality of national wheat, Brazil depends on its import. Wheat is the main ingredient of bread which is one of the most important products of Brazilian people's diet. The objective of this work was to study the effect of ionizing radiation on wheat on physicochemical, rheological, and thermal properties of flour produced from this wheat, and consequently, its performance on bread making. All experiments were conducted on laboratory scale. Wheat was submitted to irradiation on different doses (0.0; 0.5; 1.0 and 2.0 kGy) and flour produced underwent physicochemical, rheological, thermal and microbiological analyses. Flour bread making performance was measured through quality of bread. None of the physicochemical, rheological or thermal parameters was influenced by irradiation, with the exception of Falling Number, which decreased significantly with the increase of irradiation dose, indicating the effect of irradiation on wheat starch, and consequently on dough's gelatinization. Bread quality parameters did also not show significant differences, and sensory analysis showed that bread produced from irradiated and non irradiated wheat did not present perceivable flavor. (author)

  18. Quantitative chemical analysis for the standardization of copaiba oil by high resolution gas chromatography; Analise quimica quantitativa para a padronizacao do oleo de copaiba por cromatografia em fase gasosa de alta resolucao

    Energy Technology Data Exchange (ETDEWEB)

    Tappin, Marcelo R.R.; Pereira, Jislaine F.G.; Lima, Lucilene A.; Siani, Antonio C. [Farmanguinhos - Inst. de Tecnologia em Farmacos, Rio de Janeiro, RJ (Brazil)]. E-mail: siani@far.fiocruz.br; Mazzei, Jose L. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Escola de Quimica; Ramos, Monica F.S. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Farmacia. Dept. de Medicamentos

    2004-04-01

    Quantitative GC-FID was evaluated for analysis of methylated copaiba oils, using trans-(-)-caryophyllene or methyl copalate as external standards. Analytical curves showed good linearity and reproducibility in terms of correlation coefficients (0.9992 and 0.996, respectively) and relative standard deviation (< 3%). Quantification of sesquiterpenes and diterpenic acids were performed with each standard, separately. When compared with the integrator response normalization, the standardization was statistically similar for the case of methyl copalate, but the response of trans-(-)-caryophyllene was statistically (P < 0.05) different. This method showed to be suitable for classification and quality control of commercial samples of the oils. (author)

  19. Program VODAM for treatment of mineral physico-chemical data, with a special application to the uranium case; Programa VODAM para tratamiento de datos de fisico-quimica mineral. Ejemplo de aplicacion al caso del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Santoma Juncadella, L

    1972-07-01

    The VODAM program is written in FORTRAN IV language and makes a physico-chemical analysis of waters, for an element or a number of them, under investigation. A thermodynamical data files is incorporated, and is useful for a low temperature range. It is the basic nucleus for a series of programs of physico-chemical interpretation of hydrogeochemical data and automatic construction of equilibrium diagrams. (Author) 13 refs.

  20. Obtaining of a barium compound by combustion chemistry and their evaluation as Co adsorbent; Obtencion de un compuesto de bario por combustion quimica y su evaluacion como adsorbente de Co

    Energy Technology Data Exchange (ETDEWEB)

    Rosas G, N [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2008-07-01

    In this work, barium carbonate synthesized by chemical combustion method using a chemical precursor prepared by the combination of barium nitrate and urea as a fuel, with a 1:1 molar ratio in aqueous solution, the chemical precursor was heated to evaporate excess water, producing a homogeneous viscous liquid, that when heated to 900 centi grades for 5 minutes an exothermic reaction was produced very quickly and abruptly, forming a white powder final product, fine porous, little spongy, dry and crystalline ready to be used as material adsorbent. Additionally, the effect of water on the synthesis by chemical combustion was studied. Simultaneously, and with the purpose of comparing the advantages and disadvantages of the method by chemical combustion, barium carbonate was synthesized by precipitation method using barium nitrate salts and sodium carbonate. Synthesized barium carbonate, was characterized by X-ray diffraction, thermal gravimetric analysis, infrared spectrometry and scanning electron microscopy. We studied the adsorption capacity of Co present in aqueous solution by static tests on materials synthesized at room temperature using the neutron activation analysis. It was found that the synthesis by chemical combustion provides an interesting alternative compared to the synthesis by precipitation because it offers simplicity of synthesis and speed to have a good adsorbent material. It was found that the barium carbonate synthesized by the chemical combustion method using in their synthesis 1.0 ml of water, was the one who achieved the maximum adsorption capacity of 95.6% compared with the barium carbonate prepared by precipitation, which reached a capacity adsorption of 51.48%. (Author)

  1. Physicochemical characterization of steel slag post-processed as aggregate for sustainable concrete; Caracterizacao fisico-quimica de agregados de escoria de aciaria LD pos-processada para concretos sustentaveis

    Energy Technology Data Exchange (ETDEWEB)

    Souza, B.P. de; Fontes, W.C.; Carvalho, J.M.F. de; Mol, R.M.R.; Costa, E.C.P. da; Peixoto, R.A.F., E-mail: wannarquit@gmail.com [Universidade Federal de Ouro Preto (LMC/UFOP), MG (Brazil). Laboratorio de Materiais de Construcao Civil

    2016-07-01

    The concrete is the material most widely used in construction, consuming a large amount of natural resources for its production. Therefore, this work analyzes the technical and environmental aspects of concrete with full replacement of natural aggregates for processed LD steelmaking slag. The experimental program comprehends physical characterization - particle size distribution, moisture content, bulk and specific density - and elemental chemical characterization with X-Ray Fluorescence, and mineralogical characterization via X-Ray Diffraction. Morphological characterization was performed through a stereomicroscope. From these results, concrete with compressive strengths of 20 and 40 Mpa were developed, with ABPC methodology. These were characterized in the fresh and hardened states, obtaining results favorable to the steelmaking slag application in Portland cement concrete. This sustainable concrete features properties similar conventional concrete, and contributing to sustainability of buildings. (author)

  2. In vitro study of morphological and chemical modification threshold of bovine dental enamel irradiated by the holmium laser; Estudo in vitro das alteracoes morfologicas e quimicas do esmalte dental bovino irradiado pelo laser de holmio

    Energy Technology Data Exchange (ETDEWEB)

    Eduardo, Patricia Lerro de Paula

    2001-07-01

    The aim of this study is to investigate the Ho:YLF laser effects on the dental enamel surface with regards to its morphology, thermal variations during its irradiation in the pulp chamber and its increased resistance to demineralization through quantitative analysis of calcium and phosphorous atoms reactive concentrations in samples. Twenty samples of bovine enamel were used and divided in four groups: control - acidulated phosphate fluoride (APF) application followed by demineralization treatment with lactic acid; irradiation with Ho:YLF laser (100 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid; irradiation with Ho:YLF laser (350 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid: and irradiation with Ho:YLF laser ( 450 J/cm{sup 2}) followed by APF topic application and demineralization treatment with lactic acid. Ali samples were quantified according to their calcium and phosphorous atoms relative concentrations before and after the treatments above. X-Ray fluorescence spectrochemical analysis and scanning electron microscopy were carried out. It was observed an increase on the calcium and phosphorous atoms concentration ratio and therefore the enamel demineralization reduction as a result of the lactic acid treatment in the samples irradiated with the holmium laser followed by the APF application. In order to evaluate the feasibility of this study for clinical purposes, morphological changes caused by the holmium laser irradiation were analyzed. Such modifications were characterized by melted and re-solidified regions of the enamel with consequent changes on its permeability and solubility. Temperature changes of ten human pre-molars teeth irradiated with 350 J/cm{sup 2} and 450 J/cm{sup 2} were also monitored in the pulp chamber in real time. Temperature increases over 4,20 C did not occur. The results obtained from this study along with the results from previous researches developed at 'Center for Lasers and Applications (IPEN)', indicate the holmium laser as a promising alternative for the Preventive Dentistry. (author)

  3. In vitro evaluation of the chemical and morphological changes of the enamel surface using different bleaching techniques; Avaliacao in vitro das alteracoes quimica e morfologica da superficie do esmalte utilizando diferentes tecnicas de clareamento dental

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, Alessandra de Siervi

    2003-07-01

    'In vitro' evaluation through MEV and EDS of the morphological and chemical changes, respectively, of the bovine enamel, submitted to different bleaching techniques. For the MEV evaluation eighteen apical thirds were pigmented and divided into two parts. One half of each sample was the control and the other half was bleached according to the protocol of each test group (n= 6). Group I - home bleaching with a 10% carbamide peroxide; group II bleaching with 35% hydrogen peroxide and LED; group III - bleaching with 35% hydrogen peroxide with diode laser bleaching. The same procedure was done with the eighteen samples which were analyzed through EDS and which had their buccal surface grinded and polished before the bleaching procedure in order to obtain more precise values of the fraction of calcium and phosphorus. The results showed no morphological changes among the analyzed control halves and the bleached halves. There was not a statistical significant difference about Ca and P values, among the control halves and the bleached halves regarding the chemical components (p< 0,05). (author)

  4. Characterization of TiO{sub 2} thin films obtained by metal-organic chemical vapour deposition; Caracterizacao de filmes finos de TiO{sub 2} obtidos por deposicao quimica em fase vapor

    Energy Technology Data Exchange (ETDEWEB)

    Carriel, Rodrigo Crociati

    2015-07-01

    Titanium dioxide (TiO{sub 2}) thin films were grown on silicon substrate (100) by MOCVD process (chemical deposition of organometallic vapor phase). The films were grown at 400, 500, 600 and 700 ° C in a conventional horizontal equipment. Titanium tetraisopropoxide was used as source of both oxygen and titanium. Nitrogen was used as carrier and purge gas. X-ray diffraction technique was used for the characterization of the crystalline structure. Scanning electron microscopy with field emission gun was used to evaluate the morphology and thickness of the films. The films grown at 400 and 500°C presented anatase phase. The film grown at 600ºC presented rutile besides anatase phase, while the film grown at 700°C showed, in addition to anatase and rutile, brookite phase. In order to evaluate the electrochemical behavior of the films cyclic voltammetry technique was used. The tests revealed that the TiO2 films formed exclusively by the anatase phase exhibit strong capacitive character. The anodic current peak is directly proportional to the square root of the scanning rate for films grown at 500ºC, suggesting that linear diffusion is the predominant mechanism of cations transport. It was observed that in the film grown during 60 minutes the Na+ ions intercalation and deintercalation easily. The films grown in the other conditions did not present the anodic current peak, although charge was accumulated in the film. (author)

  5. Chemical signature study of tupiguarani ceramic tradition from Central region of the Rio Grande do Sul state, Brazil; Estudo de assinaturas quimicas em ceramica da tradicao tupiguarani da regiao central do estado do Rio Grande do Sul, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Bona, Irene Akemy Tomiyoshi

    2006-07-01

    In this work a model based on experimental results using chemical composition data of the pottery sherds applied to Spearmann's no parametric test, principal component analysis and discriminant analysis, was applied. The samples are soils and Tupiguarani Tradition pottery sherd from the central area of the Rio Grande do Sul State. The chemical elements , Al, Ba, Ca, Cr, Fe, K Mn, Pb, Rb, S, Si, Sr, Ti, V and Zn were determined by energy dispersive X-ray fluorescence (EDXFR) while Ce, Cu, Gd, La, Nd, Pr, Sm, Th and Y by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) techniques. Relationships among the pottery characteristics, studied sites and sherd dispersion in the several sites were proposed. Indications of chemical signature of the small pottery with function to go or not to the fire were observed. The largest dispersion is of small pottery with surface treatment no corrugated. The potteries chemical fingerprints from Ijui River, Ibicui-Vacacai Mirim River and Jacui River were verified. (author)

  6. Chemometrics application in fuel's MTR type chemical characterization by X-ray fluorescence; Aplicacao da quimiometria para caracterizacao quimica de combustiveis tipo MTR por fluorescencia de raios-X

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Clayton Pereira da

    2012-07-01

    In Brazil and worldwide the nuclear power has occupied a prominent position with many applications in industry, power generation, environment and medicine, improving the quality of tests and treatments, therefore people's lives. Uranium is the main element used in nuclear facilities and it s employed as base material to generation of electricity in the manufacture of radiopharmaceuticals. In the '50s, during the Cold War, the then newly created International Atomic Energy Agency proposed to oversee nuclear facilities and encourage the manufacture of nuclear fuels with low-enriched uranium (LEU) fuel came then type Material Test Reactor (MTR), manufactured initially in U{sub 3}O{sub 8} and U{sub 3}Si{sub 2} later, both dispersed in aluminum. The use of this technology requires a constant improvement of all processes involving the manufacture of MTR subject to several international protocols, which seek to ensure the reliability of the fuel from the standpoint of practical and environmental. In this context, the control of impurities, from the point of view of neutron economy, directly affects the quality of any nuclear fuel, so strict control is necessary. The literature has reported procedures which, beyond generating residues, are lengthy and costly, they need calibration curve and consequently reference materials. The aim of this work is to establish and validate a methodology for nondestructive quantitative chemical analysis, low cost and analysis time, as well as minimize the generation of waste, for multielement determination of major constituents (Utotal and Si) and impurities (B, Mg, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd and others) present in U3O8 and U{sub 3}Si{sub 2}, meeting the needs of nuclear reactors in the nuclear fuel qualification type MTR. For that purposes, will be applied the X-ray fluorescence technique which allows fast chemical and nondestructive analysis, aside from sample preparation procedures that do not require previous chemical treatments (dissolving, digesting, and others). To corrections like effects of spectral and matrix were applied and evaluated the fundamental parameter method, univariate calibration curve and multivariate calibration. The results were compared by means of statistical tests in accordance with ISO 17025 in MRCs (123 (1-7) and 124 (1-7)) MCRs of U{sub 3}O{sub 8} from New Brunswick Laboratory (NBL) and 16 U{sub 3}Si{sub 2} samples provided by CC of IPEN/CNEN-SP. The chemometrics is a promising method to determination of minor and major constituents on the U3Si2 and U3O8 basis nuclear fuel, because the precision and accuracy are statistically equal volumetric analysis, gravimetric and ICPOES methods. (author)

  7. Preparation of (+)-{alpha}-terpineol from (+)-limonene: monoterpenes with pleasant odor in a project for undergraduate organic chemistry laboratory; Preparacao do (+)-{alpha}-terpineola a partir do (+)-limoneno: monoterpenos de odor agradavel em um projeto para quimica organica experimental

    Energy Technology Data Exchange (ETDEWEB)

    Baptistella, Lucia Helena Brito; Imamura, Paulo Mitsuo; Melo, Leandro Vilela de; Castello, Claudio [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica], e-mail: lhbb@iqm.unicamp.br

    2009-07-01

    A synthesis of (+)-{alpha}-terpineol from (+)-limonene was proposed as a project for undergraduate organic laboratory course. Terpineol is a useful flavor and fragrance compound, and several aspects of this preparation are suited for experimental organic classes, including basic techniques for extraction and analyses of essential oils, different reaction types and the possibility of a high degree of student interest. (author)

  8. Crack propagation in stainless steel AISI 304L in Hydrogen Chemistry conditions (HWC); Propagacion de Grietas en Acero Inoxidable AISI 304L en Condiciones de Quimica de Hidrogeno (HWC)

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Fuentes C, P.; Merino C, F. [ININ, Carretera Mexico -Toluca s/n, La Marquesa, Ocoyoacac, Mexico (Mexico); Castano M, V. [Instituto de Fisica Aplicada, UNAM, Km 15.5 Carretera Queretaro-San Luis Potosi, Juriquilla, Queretaro (Mexico)]. e-mail: ads@nuclear.inin.mx

    2006-07-01

    Velocities of crack growth in samples type CT pre cracking of stainless steel AISI 304l solder and sensitized thermally its were obtained by the Rising Displacement method or of growing displacement. It was used a recirculation circuit that simulates the operation conditions of a BWR type reactor (temperature of 280 C and a pressure of 8 MPa) with the chemistry modified by the addition of hydrogen with and without the addition of impurities of a powerful oxidizer like the Cu{sup +} ion. In each essay stayed a displacement velocity was constant of 1x10{sup -9} m/s, making a continuous pursuit of the advance of the crack by the electric potential drop technique. Contrary to the idea of mitigation of the crack propagation velocity by effect of the addition of the hydrogen in the system, the values of the growth velocities obtained by this methodology went similar to the opposing ones under normal operation conditions. To the finish of the rehearsal one carries out the fractographic analysis of the propagation surfaces, which showed cracks growth in trans and intergranular way, evidencing the complexity of the regulator mechanisms of the IGSCC like in mitigation conditions as the alternative Hydrogen Chemistry. (Author)

  9. Effects on physicochemical, microbiological and sensory characteristics of honey bee samples submitted to gamma radiation; Efeitos nas caracteristicas fisico-quimicas, microbiologicas e sensoriais em amostras de mel de abelhas submetidas a radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Bera, Alexandre

    2010-07-01

    Honey production in Brazil has increased considerably and gaining pro eminence on the international market, as a result many demands have become part of the productive honey chain. In addition to the analyses provided for the Brazilian legislation, international market demand products that meet the most stringent quality standards. Honey has interesting characteristics due to its constitution, but even so there are problems that can change some how your identity and quality. The application of gamma radiation is a viable proposal which promotes the reduction of bio burden without changing the constitution and most importantly the physicochemical properties, with smaller nutritional losses when compared to other treatments used in foods. This study beyond the physicochemical parameters required by Brazilian regulation also included other relevant analyses, including FT-IR ATR. Microbiological analyses were carried out on samples of pure honeys and subsequently inoculated microbial known loads to assess the action of gamma radiation in doses of 5 and 10 kGy. The triangular test was used to differentiate the irradiated and not irradiated. samples The major changes that have occurred in samples of honeys were mainly in concentrations of HMF (hydroxymethylfurfural) and diastase activity occurring a significant decrease in all analyzed samples. There was a reduction microbiological from the application of the 5 kGy, reaching absence with 10 kGy dose except Paenibacillus larvae. The sensory analysis conducted on samples of honey and honey irradiated with 5, 10 and 15 kGy doses, pointed out that there is no significant difference (5%) between irradiated and control samples. The application of gamma radiation in honeys proved a very useful method in microbiological decontamination, featuring few changes in the product at doses up to 10 kGy. (author)

  10. Determination and analysis of the physical chemical characteristics of witness coupons of boral for the CNLV; Determinacion y analisis de las caracteristicas fisico quimicas de cupones testigo de boral para la CNLV

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez M, J.L.; Aguilar H, F.; Rivero G, T.; Carrillo M, R. [ININ, Apdo. Post 18-1027, Col Escandon, 11801 Mexico D.F. (Mexico)]. E-mail: jlgm@nuclear.inin.mx; fah@nuclear.inin.mx; trg@nuclear.inin.mx; racm@nuclear.inin.mx

    2004-07-01

    The burnt fuel elements that are extracted in each charging of the Units 1 and 2 of the Nuclear Power Plant of Laguna Verde, are deposited in shelves placed in the storage reservoir designed for this end. Each cell or storage shelf has a structure type cage. Among the cells neutron absorber material is placed, (Boral), what allows to avoid the possible criticality that could settle down when accumulating in the storage the irradiated fuel elements. This boral has been designed to maintain its characteristics of thermal neutron absorber during a lifetime of the plant. To check that the wings and the Boral have not suffered some degradation or some change due to the environmental conditions in the warehouse, it is necessary to watch over their physical and chemical characteristics periodically, what is carried out by a surveillance program based on Badges or manufactured witness coupons of the same material that the wings. The badges witness are embedded in a special wing, which is placed in the place with more radiation in the pool. In this work the laboratory tests carried out in the ININ to the coupon witness 03 of the Unit 2, (II-03) are described, being presented the results and obtained conclusions. (Author)

  11. Changes in physico-chemical properties of soil by adding organic amendments in a tomato crop; Cambios en la propiedades fisico-quimicas del suelo por adicion de enmiendas organicas en cultivo de tomate

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Navarro, A.; Marin Salneandro, P.; Delgado Iniesta, M. J.

    2009-07-01

    This study possible changes in the physico-chemical properties of soil under intensive cultivation of tomatoes after the addition of two different types of organic amendments: a natural as sheep manure and synthetic made. Trial plots that were designed are located in the NE of the province of Granada, in Puebla de Trial plots that were designed are located in the NE of the province of Granada, in Puebla de Don Fadrique, in the are that in recent years, change are very important in agriculture, from traditional farms extensive cultivation of rain-fed cereal crops such as intensive vegetale broccoli or tomatoes. (Author) 16 refs.

  12. Microstructural characteristics of steel rebar submitted to the process of self - tempering; Caracterizacao microestrutural de superficies e interfaces de vergalhoes de aco auto-revenidos utilizando Microscopia Eletronica de Varredura (MEV) e analise quimica

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, M.F.O., E-mail: matheusfob@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), MG (Brazil)

    2014-07-01

    Every day the construction industry seeks new alternatives to maximize use of the materials provided new tools for structural design of the new techniques in welding rods. In this sense, this work proposes to study the mechanical properties of steel rebar self-tempering for civil construction, choosing the bars from 6.3 to 25.4 mm in diameter for the study. The cooling process of rebar, after rolling, known as self-tempering produces a rebar with excellent mechanical properties and low cost to the plant, they put the rebar shall be composed of concentric layers with different mechanical properties among themselves. To study the influence of these layers on the mechanical behavior of rebar microstructural characterization was made by means of electron microscopy analysis of transmitted light and scanning of all samples. From the results it was found that only the bars 20 and 25mm diameter had a heat treatment for self-tempering relevant. (author)

  13. Preparation and physico-chemical characterization of inclusion complexes between local anesthetics and hydroxypropyl-{beta}-cyclodextrin; Preparacao e caracterizacao fisico-quimica de complexos de inclusao entre anestesicos locais e hidroxipropil-{beta}-ciclodextrina

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Carolina Morales; Abrami, Priscila; Goncalves, Marcos Moises; Andreo Filho, Newton [Universidade de Sorocaba, SP (Brazil); Fernandes, Sergio Antonio; Paula, Eneida de [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Biologia. Dept. de Bioquimica; Fraceto, Leonardo Fernandes [UNESP, Sorocaba, SP (Brazil). Dept. de Engenharia Ambiental]. E-mail: leonardo@sorocaba.unesp.br

    2007-07-15

    S(-) Bupivacaine (S(-)BVC) and Lidocaine (LDC) are widely used local anesthetics (LA). Hydroxypropyl {beta}-cyclodextrin (HP-{beta}-CD) is used as a drug-carrier system. The aim of this work was to characterize inclusion complexes between LA and HP-{beta}-CD. The affinity constants determined at different pHs show favourable complexation. The release kinetics experiments showed that S(-)BVC and LDC changed the released profiles in the presence of HP-{beta}-CD. Nuclear magnetic resonance experiments gave information about the interaction between LA and the cyclodextrin cavity. This study focused on the physicochemical characterization of drug-delivery formulations that come out as potentially new therapeutic options for pain treatment. (author)

  14. Aluminium polychloride in the groundwater potabilization process. Its performance as a coagulant in the aluminium chemistry domain; Policloruro de aluminio en el proceso de potabilizacion de aguas superficiales. Su comportamiento como coagulante dentro del ambito de la quimica del aluminio

    Energy Technology Data Exchange (ETDEWEB)

    Torra, A.; Valero, F. [Aigues Ter Llobregat. ATLL. Barcelona (Spain); Bisbal, J.L.; Tous, J.F. [Kemira Iberica. Barcelona (Spain)

    1998-12-01

    The development of prepolymerized coagulants of metallic salts, such as aluminium polychloride, has led to an improvement in the coagulation of drinking water and sewage, in front of the so-called hydrolyzed coagulants, such alum or ferric chloride. This paper describes the chemical properties and the advantages of the aforementioned coagulants: purification efficiency, working pH range, sensitivity to low temperatures, sludge filterability and residual Al. As a practical case it is described its application in the purification of surface waters of Llobregat river in Abrera (Barcelona). (Author) 32 refs.

  15. Evolution of {sup 222} Rn and chemical species related with eruptive processes of the Popocatepetl volcano; Evolucion de {sup 222} Rn y especies quimicas relacionadas con procesos eruptivos del volcan Popocatepetl

    Energy Technology Data Exchange (ETDEWEB)

    Aranda, P.; Ceballos, S.; Cruz, D.; Hernandez, A.; Lopez, R.; Pena, P.; Salazar, S.; Segovia, N.; Tamez, E. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    The {sup 222} Rn monitoring in the Popocatepetl volcano was initiated on 1993. At December 21, 1994 it is initiated an eruptive stage in the volcano with gas emission, ashes and the lava dome formation on the crater at middle 1996. During all this time it has been determined radon concentrations on soils with active and passive detectors. In this work the changes in radon contents are reported also the physicochemical parameters in spring water related with the volcanic building associated to the recent activity of the volcano. (Author)

  16. Chemical synthesis of composite HML / PDMcT / PAni and its application as the trhiodan adsorbent in aqueous solutions; Sintese quimica de compositos de HML/PDMcT/PAni e sua aplicacao como adsorvente do trhiodan em solucoes aquosas

    Energy Technology Data Exchange (ETDEWEB)

    Girotto, L.G.; Pacheco, I.; Freitas, L.L. de; Oliveira, R.S.; Amaral, F.A. do; Canobre, S.C., E-mail: aylagg.eab@gmail.com [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Quimica

    2016-07-01

    The mixed hydroxide lamellar [Co -Al- Cl] was synthesize by the co- precipitation method constant pH 8. The synthesis composite HML/PDMcT/PAni was carried out via chemical. The DRX composite HML/PDMcT/PAni showed that one amorphicity in the conductor polymer doesn't hid the diffraction peaks characteristic of HML. The MEV micrographs of composite HDL / PDMcT / PAni showed a large number of crystallites compacts with several shapes characteristic to PDMcT and nanofibers of polyaniline indicating an association between the different constituents forming the composite. The results of the adsorption was 98% of the pesticide in the composite HML / PDMcT / PAni , the composite can contribute so significantly to one Thiodon withdrawal in contaminated pesticide waters. (author)

  17. Effects of gamma radiation of Cobalt-60 on arabica and conillon seeds coffea: physic-chemistry evaluation; Efeitos da radiacao gama do Cobalto-60 em sementes de cafe arabica e conillon: avaliacao fisico-quimica

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcus Henriques da

    2012-07-01

    Brazil is the largest producer and exporter of coffee in the world. The coffee bean is one of the main products of the Brazilian trade balance. Two species of coffee are the most economically important: the Coffea arabica L. and Coffea canephora Pierre is the largest representative of the Coffea canephora Pierre is the coffea conillon. Food irradiation is an area of research that aims to increase the shelf life of foods and controlling pests. This study aimed to verify the physicochemical variables of Arabica coffee and conillon were affected when exposed to doses of gamma radiation from cobalt-60. The samples were provided by Polo in Coffee Quality Technology, Federal University of Lavras - UFLA. The coffee samples were subjected to irradiation doses: 0 (control), 5 kGy and 10 kGy, a multipurpose irradiator of IPEN - Research Institute of Nuclear Energy and the University of São Paulo, at a rate of 7.5 kGy / hour. For irradiation the samples were vacuum-packed in appropriate packaging aluminised. After the process of irradiation the samples were stored at a temperature of 15 ± 1 deg C and relative humidity of 17 ± 1%. The following analyzes were performed: levels of total sugars, glucose, sucrose, caffeine, humidity, pH, total acidity, electrical conductivity and fibers. Analyses were performed 1, 30, 60 and 90 days after irradiation, and the results were submitted to analysis of variance and means were compared by Tukey test at 5%. It was observed that the analysis results of the samples irradiated with 5 kGy and 10 kGy showed values similar to the control. It was concluded that irradiation did not induce deleterious effects on arabica coffee seeds and conillon irradiated with 5 kGy and 10 kGy to 90 days after irradiation. (author)

  18. Study of the influence of chemical composition on the pozzolanicity of soda-lime glass microparticles; Estudo da influencia da composicao quimica na pozolanicidade de microparticulas de vidro soda-cal

    Energy Technology Data Exchange (ETDEWEB)

    Sales, R.B.C. [Universidade do Estado de Minas Gerais (UEMG), MG (Brazil). Departamento de Ciencias e Tecnologia; Sales, F.A.; Correa, E.C.; Patricio, P. [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET-MG), MG (Brazil); Mohallem, N.D.S.; Aguilar, M.T.P., E-mail: teresa@ufmg.br [Universidade Federal de Minas Gerais (UFMG), MG (Brazil)

    2014-07-01

    The use of residues presents interesting possibilities for obtaining eco-efficient concretes. Research has investigated the use of glass residue in Portland cement composite, whether as an aggregate or a supplementary material. However, there is still no consensus on the influence of the chemical composition of glass on the behaviour of the composites in which it is used. This paper aims to analyse the influence of this composition on the performance of cement composites produced with microparticles of colourless and amber glass. Pozzolanicity was assessed by means of direct tests (modified Chapelle and electrical conductivity) and indirect tests (chemical characterization, X-ray diffraction, thermo analysis and pozzolanic activity index). Most of the results show that microparticles of both types of glass display pozzolanic activity, with no significant differences between them. This indicates the potential for the use of glass microparticles as a supplementary material in cement composites. (author)

  19. Effect of welding process on microstructure, microhardness and composition chemistry of stainless steel coatings applied by welding; Efeito do processo de soldagem na microestrutura, microdureza e composicao quimica de revestimentos de aco inoxidavel aplicados por soldagem

    Energy Technology Data Exchange (ETDEWEB)

    Melo, R.H.F. de; Maciel, T.M., E-mail: raphael.engmec@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Programa de Pos-Graduacao em Mecanica; Costa, J.; Santa, R.A.C. [Universidade Federal de Campina Grande (UFCG), Cuite, PB (Brazil). Unidade Academica de Quimica

    2012-07-01

    This study evaluates the influence of welding parameters on the chemical composition of weld overlays of the AWS E 308-L T1 applied by the FCAW and SAW process, as well as their influence on the microstructure and microhardness of the weld overlays. The characterization of chemical composition was performed by EDX (Energy Dispersive X-ray Analysis), the microstructure was investigated by optical microscopy and Vickers microhardness. The contents of Cr, Ni, Mn, Mo, Nb and Si varied as a function of welding parameters, the microstructure and microhardness varied as a function of heat input and chemical composition. The resulting microstructure showed an austenitic matrix with lacy ferrite and ferrite FA, with an average hardness of 191.6 HV for the FCAW process and 210 HV for the SAW process. (author)

  20. Analysis of energy cogeneration incentive politics to a sodium-chlorine Brazilian chemical plant energy cogeneration; Analise de politicas de incentivo a cogeracao de energia numa planta quimica brasileira de soda-cloro

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, J.B.V.; Borschiver, S. [Universidade Federal do Rio de Janeiro (CT/UFRJ), RJ (Brazil). Centro de Tecnologia], E-mail: suzana@eq.ufrj.br; Szklo, A.S. [Universidade Federal do Rio de Janeiro (PPE/COPPE/UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia. Programa de Planejamento Energetico], E-mail: szklo@ppe.ufrj.br; Andrade, M.H.S. [Braskem S.A., Rio de Janeiro, RJ (Brazil)], E-mail: marcio.andrade@braskem.com.br

    2010-07-01

    This paper evaluates, from a pont of view of investor and through the use of a simulator, the impact of incentive politics to the cogeneration, from the sugar cane bagasse, at a plant for production of sodium-chlorine.

  1. Physical and chemical evaluation of the effect of a magnetic field on the electrodeposition of Ni in low carbon steel; Evaluacion fisica y quimica del efecto de un campo magnetico en la electrodeposicion de Ni en acero bajo carbono

    Energy Technology Data Exchange (ETDEWEB)

    Campo G, G. A.

    2015-07-01

    In this study nickel coatings were obtained, with and without the presence of magnetic field at 60 degrees Celsius for 7, 12 and 17 minutes on substrates of AISI 1018 carbon steel, from a classical type Watts solution. The properties of the coatings were studied by X-ray diffraction, scanning electron microscopy and atomic force microscopy, hardness tester and roughness tester, the electrochemical behavior of the films was also studied through RP and EIE and also capacitance calculations, corrosion rate and thickness were made. In general, the magnetic field has a negative influence on the physical and chemical properties of an electrodeposited Ni steel AISI 1018. The details are discussed in this research. (Author)

  2. Effects of ionizing radiation in the physico-chemical characteristics of red wine Cabernet Sauvignon; Efeitos da radiacao ionizante nas caracteristicas fisico-quimicas do vinho tinto Cabernet Sauvignon

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Fellipe Souza da; Leiras, Anderson; Wagner, Walsan, E-mail: fellipe.souzadasilva@gmail.com [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    The oenology in the current days is increasingly aimed obtain improvements on wine quality produced without there the deterioration of characteristics of the same, using new technologies for such order. The objective of present work will be the application of the radiation ionizing in wines Cabernet Sauvignon, with the interest of analyzing its effects on physic-chemical characteristics of this wines, such as quality, aging and etc. Were analyzed the following strands: degree alcoholic; dry extract; density and absorbance with spectrometer (420, 520 and 620 nm). (author)

  3. Detección de patrones y anomalías espectrales del terreno mediante espectrometría de imagen de alta resolución : reconocimiento, optimización y evaluación multiescenario

    OpenAIRE

    Rejas Ayuga, Juan Gregorio

    2014-01-01

    El objeto de esta Tesis doctoral es el desarrollo de una metodologia para la deteccion automatica de anomalias a partir de datos hiperespectrales o espectrometria de imagen, y su cartografiado bajo diferentes condiciones tipologicas de superficie y terreno. La tecnologia hiperespectral o espectrometria de imagen ofrece la posibilidad potencial de caracterizar con precision el estado de los materiales que conforman las diversas superficies en base a su respuesta espectral. Es...

  4. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Author Affiliations. Abraham F Jalbout1 Md Abul Haider Shipar2. Instituto de Quimica, Universidad Nacional Autonoma de Mexico, Mexico City, Mexico; Faculty of Engineering, Chiba University, Inage-ku, Chiba 263-8522, Japan ...

  5. Equilibrium and Kinetic Studies of Cu (II), Cd (II), Pb (II) and Fe (II ...

    African Journals Online (AJOL)

    ADOWIE PERE

    from Aqueous Solution Using Cocoa (Theobroma cacao) Pod Husk. *1. OBIKE, AI;. 1. IGWE, JC;. 1. EMERUWA, CN;. 2. UWAKWE, KJ. 1 Department of Pure & Industrial Chemistry, Abia State University, Uturu, Abia State, ..... Eclectica Quimica.

  6. Meeting on Solute/Solvent Interactions Held in Aberdeen Proving Ground, Maryland on May 29-30, 1991

    Science.gov (United States)

    1992-01-01

    the magnitudes of the nuclear charges and therefore cannot be assumed to indicate relative reactivities toward nucleophiles. There is accordingly no...APPENDIX 3 ORGANIZATIONS OF AUTHORS IN THESE PROCEEDINGS Central Michigan University 49 Instituto de Quimica Fisica 33 La Sierra University, Riverside 71...Aberdeen Proving Gd, MD Joxe-Luis Abbud Christopher Cramer Instituto de Quimica Fisica SMCCR-RSP-C "Rocasolano" U.S. Army Chemical RD&E Center Conajo

  7. Redes de colaboração científica na área de química no Brasil: um estudo baseado nas coautorias dos artigos da revista Química Nova

    Directory of Open Access Journals (Sweden)

    Cristina Gomes de Souza

    2012-01-01

    Full Text Available In this paper we built three co-authorship networks displaying the acquaintances between countries, universities and authors that have published papers in Quimica Nova from 1995 to 2008. Our research was conducted applying a bibliometric approach to 1782 papers and over 4200 authors. Centrality measures were used and the most significant actors of each network were pointed out. The results using the centrality metrics and the network structures indicated that Quimica Nova resembles a typical scientific community.

  8. Area Handbook Series: Portugal, A Country Study

    Science.gov (United States)

    1993-01-01

    result of their excessive dependence on debt financing, Quimigal and Setenave, as well as Companhia Nacional de Petro- quimica (CNP), a state-owned...Gerais de Material de Engenharia (OGME) for the overhaul of military vehicles; and Oficinas Gerais de Material Aeronautico (OGMA) for maintenance and...CNP. See Companhia Nacional de Petro- (CCP). See Portuguese Confederation quimica of Commerce coal, 149 Confederaqio Geral dos Trabalhadores coastline

  9. International Symposium on Electrochemical Impedance Spectroscopy (2nd) Held in Santa Barbara, California on 12-17 July 1992 (Extended Abstracts)

    Science.gov (United States)

    1992-01-01

    Aplicada. M.Martinez and S.Bruque, Departamento.de Quimica Inorgknica. Facultad de Ciencias, Universidad de MAlaga, E-29071 Milaga,(SPAIN). Hydrogen...Departamento de QuImica , Universidade de Coimbra, 3049 Coimbra Codex, Portugal Studies of aluminium corrosion in chloride media have been carried out under a...Caixa Postal 68505, CEP: 21945, RJ, Brazil. z-Depto. de Fisico-Qulmica - IQ/UFRJ - RJ, Brazil. 9-Escola de Engenharia - UFRJ - RJ, Brazil. INTRODUCTION

  10. Determination of fluconazole in serum and amniotic fluid of rats by gas-chromatography/mass spectometry (GC/MS Determinação de fluconazol em soro e líquido amniótico de ratas por cromatografia a gas/espectrometria de massas (CG/EM

    Directory of Open Access Journals (Sweden)

    Dione Marçal Lima

    2005-06-01

    Full Text Available Rats treated with oral dose of 100 mg/kg of fluconazole during pregnancy had their serum and amniotic fluid quantified for this drug using a GC/MS method. Fluconazole was extracted with ethyl acetate from samples and analysed by a GC-MS Shimadzu QP5050A system using a CBP-5 fused silica capillary column. Tioconazole was used as internal standard. Calibration curve was linear within the range 10.0 - 300.0 µg/mL. The limit of quantification was 0.1 µg/mL and no interference was observed in the blank serum and amniotic liquid. The mean concentrations of the drug in the serum and amniotic fluid were 206.01 ± 105.25 µg/mL and 125.34 ± 65.24 mug/mL, respectively. This procedure showed to be sensitive and efficient enough for the use in teratogenic studies of fluconazole and other azole drugs.Soro e líquido amniótico de ratas tratadas com fluconazol (dose oral de 100 mg/kg durante a prenhez foram quantificados para este fármaco usando cromatografia gasosa acoplada à espectroscopia de massas (CG/EM. O fluconazol foi extraído das amostras com acetato de etila e analisado empregando-se um cromatógrafo CG/EM Shimadzu QP5050A com coluna capilar de sílica fundida CBP-5. O tioconazol foi utilizado como padrão interno. A curva padrão foi linear no intervalo das concentrações de 10,0 a 300,0 µg/mL. O limite de quantificação foi de 0,1 µg/mL e não foi observada interferência no branco de soro e líquido amniótico. As concentrações médias do fármaco no soro e líquido amniótico foram 206,01 ± 105,25 µg/mL e 125,34 ± 65,24 µg/mL, respectivamente. Este procedimento mostrou-se sensível e eficiente para ser usado em estudos de teratogenicidade do fluconazol e outros azóis.

  11. Análise direta de sólidos por espectrometria de absorção atômica com atomização em forno de grafite: uma revisão Solid sampling graphite furnace atomic absorption spectrometry: a review

    Directory of Open Access Journals (Sweden)

    Cassiana Seimi Nomura

    2008-01-01

    Full Text Available This is a review of direct analysis using solid sampling graphite furnace atomic absorption spectrometry. Greater emphasis is dedicated to sample preparation, sample homogeneity, calibration and its application to microanalysis and micro-homogeneity studies. The main advantages and some difficulties related to the applicability of this technique are discussed. A literature search on the application of solid sampling graphite furnace atomic absorption spectrometry in trace element determination in many kinds of samples, including biological, clinical, technological and environmental ones, is also presented.

  12. Chemical characterization of neonicotinoids in surface waters by high performance liquid chromatography with Tandem Mass Spectrometry (HPLC MS/MS); Caracterização química dos neonicotinóides em águas superficiais via cromatografia liquída de alta eficiência acoplada a Espectrometria de Massas em Tandem (HPLC-MS/MS)

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Priscila Oliveira

    2017-07-01

    The present study aimed to develop a method for the determination and validation of a method for the identification and quantification of Neonicotinoids in surface waters collected in the Bauru region, in the state of São Paulo. The analytical techniques studied for the development of this method were the high performance liquid chromatography with tandem mass spectrometry (HPLC - MS / MS), gas chromatography with mass spectrometry (GC / MS) and gas chromatography with electron capture detector (GC / ECD). The class of pesticides Neonicotinoids was chosen for this work because it is related to a sudden disappearance of bees in colonies around the world. This phenomenon is known as Colony Collapse Disorder (CCD) and it is characterized by a rapid loss in the population of adult bees. The Neonicotinoids used in this study were the compounds Clothianidin, Imidacloprid and Thiamethoxam which were banned in their use as pesticides in Europe by Implementing Regulation No. 540/2011. The samples were concentrated using solid phase extraction (SPE) and liquid liquid extraction (LLE) techniques and injected into HPLC-MS / MS, GC / MS and GC / ECD. The GC / ECD and GC / MS techniques were not satisfactory for determination in the water matrix because the detection limit (10 mg L{sup -1}) is above the maximum allowed by the US Environmental Protection Agency (0.6 μg L{sup -1}). The HPLC - MS / MS technique using the multiple reaction monitoring (MRM) proved to be adequate for this study because it obtained quantification limits between 5.89 and 8.06 μg L{sup -1} and a linearity between 0.9963 and 0.9999 for the three compounds. (author)

  13. Análise de aminas aromáticas em amostras de interesse ambiental por cromatografia líquida de alta eficiência acoplada a detectores de arranjo de diodo, eletroquímico e espectrometria de massas: Thiago Mescoloto Lizier. -

    OpenAIRE

    Lizier,Thiago Mescoloto [UNESP

    2014-01-01

    This work investigates new analytical methods for analysis of aromatic amines selected because of their toxicological and/or mutagenic properties in samples of environmental interest using chromatographic techniques with various detectors. After optimization of chromatographic conditions as aromatic amines: 4,4'-oxydianiline, aniline, 2,4-diaminotoluidina, 4,4'- diaminobifenila, 4,4'-methylenebis-(2-chloroaniline), 3,3'-dichlorobenzidine, 2- aminonaphthalene, 2-methylaniline, 2-methoxyaniline...

  14. Introduction to Body Composition Assessment Using the Deuterium Dilution Technique with Analysis of Urine Samples by Isotope Ratio Mass Spectrometry (Spanish Edition); Introduccion a la determinacion de la composicion corporal mediante la tecnica de dilucion de deuterio con analisis de muestras de orina por espectrometria de masas de relacion isotopica

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-11-15

    The IAEA has fostered the more widespread use of a stable isotope technique to assess body composition in different population groups to address priority areas in public health nutrition in Member States. It has done this by supporting national and regional nutrition projects through its technical cooperation programme and coordinated research projects over many years. This publication was developed by an international group of experts to provide practical hands-on guidance in the use of this technique in settings where analysis of stable isotope ratios in biological samples is to be made by isotope ratio mass spectrometry. The publication is targeted at new users of this technique, for example nutritionists, analytical chemists and other professionals. More detailed information on the theoretical background and the practical applications of state of the art methodologies to monitor changes in body composition can be found in IAEA Human Health Series No. 3, Assessment of Body Composition and Total Energy Expenditure in Humans by Stable Isotope Techniques.

  15. Introduction to Body Composition Assessment Using the Deuterium Dilution Technique with Analysis of Saliva Samples by Fourier Transform Infrared Spectrometry (Spanish Edition); Introduccion a la determinacion de la composicion corporal mediante la tecnica de dilucion de deuterio con analisis de muestras de saliva por espectrometria infrarroja por transformada de Fourier

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-12-15

    For many years, the IAEA has fostered the more widespread use of stable isotope techniques to assess body composition in different population groups to address priority areas in public health nutrition in Member States. The objective is to support national and regional nutrition projects through both the IAEA's technical cooperation programme and its coordinated research projects. In particular, during the last few years, the increased access to analyses of deuterium enrichment by Fourier transform infrared (FTIR) spectrometry has increased the application of this technique in Africa, Asia and Latin America. This publication was developed by an international group of experts to provide practical, hands-on guidance in the use of this technique in settings where the analysis of deuterium enrichment in saliva samples will be made by FTIR. It is targeted at new users of this technique, for example nutritionists, analytical chemists and other professionals. More detailed information on the theoretical background and the practical application of state of the art methodologies to monitor changes in body composition can be found in an IAEA publication entitled Assessment of Body Composition and Total Energy Expenditure in Humans by Stable Isotope Techniques (IAEA Human Health Series No. 3)

  16. Determinação direta de Ca, Mg, Mn e Zn em amostras de leite de búfala da Ilha de Marajó por espectrometria de absorção atômica com chama (FAAS Direct determination of Ca, Mg, Mn and Zn in buffalo milk of the Marajó Island by FAAS

    Directory of Open Access Journals (Sweden)

    João B. Pereira Junior

    2009-01-01

    Full Text Available This work proposes an analytical procedure for direct determination of calcium, magnesium, manganese and zinc in buffalo milk by flame atomic absorption spectrometry (FAAS. Samples were diluted with a solution containing 10% (v/v of water-soluble tertiary amines (CFA-C at pH 8. For comparison, buffalo milk samples were digested with HNO3 and H2O2. According to a paired t-test, the results obtained in the determination of Ca, Mg, Mn and Zn in digested samples and in 10% (v/v CFA-C medium were in agreement at a 95% confidence level. The developed procedure is simple, rapid, decrease the possibility of contamination and can be applied for the routine determination of Ca, Mg, Mn and Zn in buffalo milk samples without any difficulty caused by matrix constituents, such as fat content, and particle size distribution in the milk emulsion.

  17. QuEChERS: um método moderno de preparo de amostra para determinação multirresíduo de pesticidas em alimentos por métodos cromatográficos acoplados à espectrometria de massas QuEChERS: a modern sample preparation method for pesticide multiresidue determination in food by chromatographic methods coupled to mass spectrometry

    Directory of Open Access Journals (Sweden)

    Osmar D. Prestes

    2009-01-01

    Full Text Available This review attempts to provide an updated overview of the Quick, Easy, Cheap, Effective, Ruged and Safe (QuEChERS multiresidue extraction method, that involves initial extraction in acetonitrile, an extraction/partition step after the addition of salt, and a cleanup step utilizing dispersive solid phase extraction. QuEChERS method is nowadays the most applied extraction method for the determination of pesticide residues in food samples, providing acceptable recoveries for acidic, neutral and basic pesticides. Several applications for various food matrices (fruits, vegetables, cereals and others in combination with chromatographic mass spectrometry analysis were presented.

  18. Determination of the isotopic ratio {sup 234} U/{sup 238} U and {sup 235} U/{sup 238} U in uranium commercial reagents by alpha spectroscopy; Determinacion de la relacion isotopica {sup 234} U/{sup 238} U y {sup 235} U/{sup 238} U en reactivos comerciales de uranio por espectrometria alfa

    Energy Technology Data Exchange (ETDEWEB)

    Iturbe G, J L

    1990-02-15

    In this work the determination of the isotope ratio {sup 234} U/{sup 238} U and {sup 235} U/{sup 238} U obtained by means of the alpha spectroscopy technique in uranium reagents of commercial marks is presented. The analyzed uranium reagents were: UO{sub 2} (*) nuclear purity, UO{sub 3} (*) poly-science, metallic uranium, uranyl nitrate and uranyl acetate Merck, uranyl acetate and uranyl nitrate Baker, uranyl nitrate (*) of the Refinement and Conversion Department of the ININ, uranyl acetate (*) Medi-Lab Sigma of Mexico and uranyl nitrate Em Science. The obtained results show that the reagents that are suitable with asterisk (*) are in radioactive balance among the one {sup 234} U/{sup 238} U, since the obtained value went near to the unit. In the case of the isotope ratio {sup 235} U/{sup 238} U the near value was also obtained the one that marks the literature that is to say 0.04347, what indicates that these reagents contain the isotope of {sup 235} U in the percentage found in the nature of 0.71%. The other reagents are in radioactive imbalance among the {sup 234} U/{sup 238} U, the found values fluctuated between 0.4187 and 0.1677, and for the quotient of activities {sup 235} U/{sup 238} U its were of 0.0226, and the lowest of 0.01084. Also in these reagents it was at the {sup 236} U as impurity. The isotope of {sup 236} U is an isotope produced artificially, for what is supposed that the reagents that are in radioactive imbalance were synthesized starting from irradiated fuel. (Author)

  19. Characterization of chemical elements in soil submitted to different systems use and management by energy dispersive x-ray fluorescence spectrometry (EDXRF); Caracterizacao dos niveis de elementos quimicos em solo, submetido a diferentes sistemasde uso e manejo, utilizando espectrometria de fluorescencia de raios-X por energia dispersiva (EDXRF)

    Energy Technology Data Exchange (ETDEWEB)

    Wastowski, Arci Dirceu; Rosa, Genesio Mario da; Cherubin, Mauricio Roberto; Rigon, Joao Paulo Gonsiorkiewicz, E-mail: wastowski@smail.ufsm.b [Universidade Federal de Santa Maria (UFSM), Frederico Westphalen, RS (Brazil). Centro de Educacao Superior Norte do Rio Grande do Sul

    2010-07-01

    This study aimed to evaluate the chemical elements levels in soil, submitted to different management systems and use by the Energy Dispersive X-Ray Fluorescence Spectrometry - EDXRF. The systems were T1 - agroforestry (SAF), T2 - native field (CN), T3 - native forest (NM), T4 - tillage forest (PF); T5 - conventional tillage system (SPC) and T6 - system tillage (NT). Samples were collected at 0-10 and 10-20 cm, dried and ground for analysis in EDX-720. The soil showed no difference in the average concentrations of chemical elements analyzed in the profiles, but the systems presented different concentrations of metal elements, and T3 had the highest K, Ca and Zn at 0-10 cm and higher contents of K, Ca, Cu, Zn and Mn in the layer of 10-20 cm. (author)

  20. Emprego da amostragem de suspensão na determinação de Cu e Zn em lapa antártica e Ni em sedimento de rio por espectrometria de absorção atômica com chama

    Directory of Open Access Journals (Sweden)

    Alves Flávia de Lima

    2001-01-01

    Full Text Available In order to demonstrate the feasibility of slurry sampling for environmental studies, different methodologies were developed for Cu and Zn in antarctic limpets and Ni in river sediment with FAAS detection. Studies focusing particle size, acid concentration, slurry stability, selectivity, among others were carried out in order to define the better conditions for slurry analysis. A study related to the depth profile for Ni in the Atibaia River sediment was made after optimization conditions for this element. For accuracy check, certified reference material was used as well as decomposition with microwave oven.

  1. Determinação de fósforo em aços por espectrometria de absorção atômica no forno de grafite Determination of phosphorus in steel samples by graphite furnace atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Adilson José Curtius

    1998-06-01

    Full Text Available A method for the determination of phosphorus in steel samples by graphite furnace atomic absorption spectrometry, using the Zeeman effect background correction and the STPF conditions is proposed. The effect of iron (III on the phosphorus signal was studied. It was verified, through the pyrolysis temperature curves, that iron (III is an efficient chemical modifier, thermically stabilizing phosphorus up to 1400ºC. The phosphorus signal increases with the iron (III concentration, but in the range, which corresponds to the usual concentrations of iron in the sample solutions, the increase is small. Phosphorus was determined in three standard reference materials, after its dissolution in a mixture of hydrochloric and perchloric acids in a PTFE bomb. The agreement with the certified concentration values was excellent. Iron (III was added to the reference analytical solutions prepared in the blank of the dissolution, while the sample solutions were measured directly, since they already contained the modifier. The detection limit (k = 2 was 0.0042% of phosphorus in the steel sample.

  2. Determinação de As em amostras orgânicas de interesse ambiental por espectrometria de absorção atômica com atomização eletrotérmica após combustão em bomba de O2

    OpenAIRE

    Dias Vera Maria da Costa; Satte Maria Salete Selaimen

    2003-01-01

    The toxicity of the major As species present in the environment justifies the effort for quantifying the element in environmental organic samples, which can vary from animal and vegetal tissues to coal and industrial residues. This paper comments about the applicability of the O2 bomb digestion, as a general procedure for all environmental organic materials. A rapid and straightforward method is suggested, which consists in burning the sample in the bomb at high O2 pressure, dissolving the va...

  3. Validation of an analytical method for the determination of total mercury in urine samples using cold vapor atomic absorption spectrometry (CV-AAS); Validacao de metodologia analitica para determinacao de mercurio total em amostras de urina por espectrometria de absorcao atomica com geracao de vapor frio (CV-AAS)

    Energy Technology Data Exchange (ETDEWEB)

    Guilhen, Sabine Neusatz

    2009-07-01

    Mercury (Hg) is a toxic metal applied to a variety of products and processes, representing a risk to the health of occupationally or accidentally exposed subjects. Dental amalgam is a restorative material composed of metallic mercury, which use has been widely debated in the last decades. Due to the dubiety of the studies concerning dental amalgam, many efforts concerning this issue have been conducted. The Tropical Medicine Foundation (Tocantins, Brazil) has recently initiated a study to evaluate the environmental and occupational levels of exposure to mercury in dentistry attendants at public consulting rooms in the city of Araguaina (TO). In collaboration with this study, the laboratory of analysis at IPEN's Chemistry and Environment Center is undertaking the analysis of mercury levels in exposed subjects' urine samples using cold vapor atomic absorption spectrometry. This analysis requires the definition of a methodology capable of generating reliable results. Such methodology can only be implemented after a rigorous validation procedure. As part of this work, a series of tests were conducted in order to confirm the suitability of the selected methodology and to assert that the laboratory addresses all requirements needed for a successful implementation of the methodology. The following parameters were considered in order to test the method’s performance: detection and quantitation limits, selectivity, sensitivity, linearity, accuracy and precision. The assays were carried out with certified reference material, which assures the traceability of the results. Taking into account the estimated parameters, the method can be considered suitable for the afore mentioned purpose. The mercury concentration found for the reference material was of (95,12 ± 11,70)μg.L{sup -1} with a recovery rate of 97%. The method was also applied to 39 urine samples, six of which (15%) showing urinary mercury levels above the normal limit of 10μg.L{sup −1}. The obtained results fall into a range of concentration from 1,02 to 23,36μg.L{sup −1}. (author)

  4. Study of the influence of PPO in the compatibility of the system PA6/PC/PPO through nuclear magnetic resonance II - Composition changes in the PA6/PC/PPO system; Estudo da afluencia do PPo na compatibilidade do sistema PA6/PC/PPO atraves de espectrometria de resonancia magnetica nuclear. II - Mudanca na composicao do sistema PA6/PC/PPO

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Dilma Alves; Oliveira, Clara Marize F.; Tavares, Maria Ines Bruno [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas; Menezes, Sonia M.C. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisa

    1997-12-31

    This work aims to study the influence in the quantities of poly(propylene oxide) in the miscibility of the system 6-poly-amide/ poly - carbonate / poly (propylene oxide). NMR was used as chemical instrumental technique for the analysis. Results are presented 15 refs.

  5. Validation of an analytical method for the determination of total mercury in urine samples using cold vapor atomic absorption spectrometry (CV-AAS); Validacao de metodologia analitica para determinacao de mercurio total em amostras de urina para espectrometria de absorcao atomica com geracao de vapor frio (CV-AAS)

    Energy Technology Data Exchange (ETDEWEB)

    Guilhen, Sabine Neusatz

    2009-07-01

    Mercury (Hg) is a toxic metal applied to a variety of products and processes, representing a risk to the health of occupationally or accidentally exposed subjects. Dental amalgam is a restorative material composed of metallic mercury, which use has been widely debated in the last decades. Due to the dubiety of the studies concerning dental amalgam, many efforts concerning this issue have been conducted. The Tropical Medicine Foundation (Tocantins, Brazil) has recently initiated a study to evaluate the environmental and occupational levels of exposure to mercury in dentistry attendants at public consulting rooms in the city of Araguaina (TO). In collaboration with this study, the laboratory of analysis at IPEN's Chemistry and Environment Center is undertaking the analysis of mercury levels in exposed subjects' urine samples using cold vapor atomic absorption spectrometry. This analysis requires the definition of a methodology capable of generating reliable results. Such methodology can only be implemented after a rigorous validation procedure. As part of this work, a series of tests were conducted in order to confirm the suitability of the selected methodology and to assert that the laboratory addresses all requirements needed for a successful implementation of the methodology. The following parameters were considered in order to test the method's performance: detection and quantitation limits, selectivity, sensitivity, linearity, accuracy and precision. The assays were carried out with certified reference material, which assures the traceability of the results. Taking into account the estimated parameters, the method can be considered suitable for the afore mentioned purpose. The mercury concentration found for the reference material was of (95,12 +- 11,70)mug.L{sup -1} with a recovery rate of 97%. The method was also applied to 39 urine samples, six of which (15%) showing urinary mercury levels above the normal limit of 10{mu}g.L{sup -1}. The obtained results fall into a range of concentration from 1,02 to 23,36{mu}g.L{sup -1}. (author)

  6. Pré-concentração de cádmio com Saccharomyces cerevisiae e determinação em águas fluviais usando espectrometria de emissão óptica com plasma indutivamente acoplado Preconcentration of cadmium with Saccharomyces cerevisiae and determination in river water using inductively coupled plasma optical emission spectrometry

    Directory of Open Access Journals (Sweden)

    Priscila Andreoli Biscaro

    2007-04-01

    Full Text Available A preconcentration method based on the use of Saccharomyces cerevisiae as sorbent material is proposed for the determination of Cd(II in river water. The solid phase extraction was performed in batch mode and the determination of the analyte in the solid phase was easily carried out by introducing a slurry of the yeast (0.0625 g / 2.5 mL directly into the ICP OES. A limit of detection of 0.11 µg L-1 and a sample throughput in the range of 4 - 54 sample h-1 were obtained. Determinations of cadmium in a certified sample and in real river water samples were in excellent agreement with the expected values.

  7. Determinação de resíduos de cloranfenicol em amostras de leite e mel industrializados utilizando a técnica de espectrometria de massas em "tandem" (CLAE-EM/EM Determination of chloramphenicol residues in industrialized milk and honey samples using LC-MS/MS

    Directory of Open Access Journals (Sweden)

    Helio Alves Martins Júnior

    2006-06-01

    Full Text Available The present work shows a method for the determination of chloramphenicol (CAP antibiotic in milk, powder milk and honey. The solid phase extraction and liquid-liquid extraction were applied as a clean-up and pre-concentration strategies followed by LC-ESI/MS/MS analysis. The recovery was studied for different fortification levels from 0.05 to 1.00 µg L-1 in milk, showing values between 91 101% and RSD bellow 8.0%, while honey was spiked with a concentration of 0.20 µg kg-1 yelding a mean recovery of 83% and RSD of 6.5%. The quantification transition 321>152 showed a LOD of 0.52 ng kg-1 and LOQ of 1.85 ng kg-1.

  8. Development of an analytical model for the determination of {sup 60}Co in aqueous samples by atomic absorption and gamma spectrometry techniques; Elaboracion de un modelo analitico para la determinacion de {sup 60}Co en muestras acuosas mediante tecnicas de absorcion atomica y espectrometria gamma

    Energy Technology Data Exchange (ETDEWEB)

    Solis A, N. A.

    2015-07-01

    The applications of the nuclear energy in industry and medicine generate radioactive wastes that must be isolated and confined in order to limit its spread in the biosphere. These types of wastes are generated in hospitals, industry, research centers and nuclear power plants (during de fuel cycle). The radioactive elements (radionuclides) cannot be destroyed by any known method, either chemical or mechanical. Its final destruction is produced by radioactive decay, which makes them stable isotopes, or nuclear transmutation being bombarded with atomic particles. Consequently, the radioactive waste management is to control the radioactive discharges and reduce to tolerable limits, eliminating of effluents and wastes the radionuclides of interest, concentrating them so they can be stored or evacuated so that later not appear in dangerous concentration in the biosphere. In Mexico, the main generators of radioactive wastes are the nuclear power plant of Laguna Verde in Veracruz, Hospitals of the public and private sector, in addition Instituto Nacional de Investigaciones Nucleares (ININ) some institutes and facilities of the UNAM and Instituto Politecnico Nacional (IPN) and industries among others. The aqueous radioactive wastes, particularly those from the nuclear power plants contain traces of cobalt-60. Currently there is no model or analytical technique for the separation of this radionuclide, so it became necessary to develop an analytical model for separation and facilitate their disposal. In this paper was shown that atomic absorption and gamma spectrometry techniques can separate the active concentration of the inactive, which is important because the total concentration can be associated through direct relationships with the wear of metal parts of the nuclear reactor, since the metal alloys of the same reactor containing a fraction of cobalt. Also this analytical and mathematical model that can be reproducible and applicable to full sets of samples and that this correlation can be interpreted graphically to obtain approximate values for active or inactive cobalt concentration. (Author)

  9. Avaliacão de programas de aquecimento para espectrometria de absorção atômica com atomizacão eletrotérmica em filamento de tungstênio Evaluation of heating programs for electrothermal atomic absorption spectrometry using a tungsten coil

    Directory of Open Access Journals (Sweden)

    Pedro V. Oliveira

    2000-10-01

    Full Text Available A tungsten coil atomizer was used to investigate the effect of heating programs with constant or variable drying temperatures on the atomization of Al, Cd, Cr and Pb. The variation of the surface temperature in the tungsten coil furnace can occur during each heating step due to the design of the power supply, that may apply constant voltages during a programmed time. For volatile elements (Cd, losses in sensitivity were observed when the program with a variable temperature was used. On the other hand, these effects are negligible for less volatile elements (Al and Cr and any tested program, in different acidic media, could be used without appreciable changes in sensitivities. The results allow the establishment of proper heating programs for elements with different thermochemical behavior in the tungsten coil atomizer.

  10. Absolute standardization of radionuclides with complex decay by the peak-sum coincidence method and photon spectrometry with HPGe detector; Padronização primária de radionuclídeos com decaimento complexo pelo método de coincidência pico-soma espectrometria de fótons com detector GeHP

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ronaldo Lins da

    2017-07-01

    This study aims to present a new methodology for absolute standardization of {sup 133}Ba, which is a complex decay radionuclide, using the peak-sum coincidence method associated with gamma spectrometry with a high resolution germanium detector. The use of the method of direct multiplication of matrices allowed identifying all the energies of sum coincidence, as well as their probabilities of detection, which made possible the calculation of the probabilities of detecting the energies of interferences. In addition, with the use of deconvolution software it was possible to obtain the areas of energy without interference of other sums, and by means of the deduced equation for the peak sum method, it was possible to standardize {sup 133}Ba. The result of the activity was compared with those found by the absolute methods existing in the LNMRI, where the result obtained by coincidence peak-sum was highlighted among all. The estimated uncertainties were below 0.30%, compatible with the results found in the literature by other absolute methods. Thus, it was verified that the methodology was able to standardize radionuclide {sup 133}Ba with precision, accuracy, easiness and quickness. The relevance of this doctoral thesis is to provide the National Metrology Laboratory of Ionizing Radiation (LNMRI) with a new absolute standardization methodology for complex decay radionuclides. (author)

  11. Aplicação de métodos quimiométricos na caracterização de charutos utilizando extração por dispersão da matriz em fase sólida e análise por cromatografia gasosa acoplada à espectrometria de massas

    Directory of Open Access Journals (Sweden)

    Vanessa de Menezes Prata

    2011-01-01

    Full Text Available In this work, the organic compounds of cigar samples from different brands were analyzed. The compound extraction was made using the matrix solid-phase dispersion (MSPD technique, followed by gas chromatography and identification by mass spectrometry (GC-MS and standards, when available. Thirty eight organic compounds were found in seven different brands. Finally, with the objective of characterizing and discriminating the cigar samples, multivariate statistical analyses were applied to data, e.g.; principal component analysis (PCA and hierarchical cluster analysis (HCA. With such analyses, it was possible to discriminate three main groups of three quality levels.

  12. Caracterização dos níveis de elementos químicos em solo, submetido a diferentes sistemas de uso e manejo, utilizando espectrometria de fluorescência de raios-x por energia dispersiva (EDXRF Characterization of chemical elements in soil submitted to different systems use and management by energy dispersive x-ray fluorescence spectrometry (EDXRF

    Directory of Open Access Journals (Sweden)

    Arci Dirceu Wastowski

    2010-01-01

    Full Text Available This study aimed to evaluate the chemical elements levels in soil, submitted to different management systems and use by the Energy Dispersive X-Ray Fluorescence Spectrometry - EDXRF. The systems were T1 - agro forestry (SAF, T2 - Native Field (CN, T3 - Native Forest (NM, T4 - Tillage Forest (PF; T5 - conventional tillage system (SPC and T6 - System tillage (NT. Samples were collected at 0-10 and 10-20 cm, dried and ground for analysis in EDX-720. The soil showed no difference in the average concentrations of chemical elements analyzed in the profiles, but the systems presented different concentrations of metal elements, and T3 had the highest K, Ca and Zn at 0-10 cm and higher contents of K, Ca, Cu, Zn and Mn in the layer of 10-20 cm.

  13. Analysis of sodium metal by X-ray fluorescence spectrometry (I). Determination of Hf, Mo, Nb, Ta, Ti, V and Zr; Analisis de sodio metal por espectrometria de fluorescencia de rayos X. Determinacion de Hf, Mo, Nb, Ta, Ti, V y Zr

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Guerra, J P

    1981-07-01

    A method allowing the determination of trace quantities of Hf, Mo, Nb, Ta, Ti, Vi and Zr in sodium metal previous transformation into Na{sub 2}S0{sub 4} is described. The enrichment of the impurities is performed through a coprecipitation technique in sulfuric medium by using Fe{sup 3}+ as a collector and cupferron or phenyfluorone as the precipitating reagent. The matrix influence and the best concentration of the collector (10/{mu}/ml), adequate pH (1,3 or 4, respectively) and optimum filter type (Millipore BSWP02500 or BDWP04700, respectively) have been studied, as well as the precipitation recoveries corresponding to the reagent above. It has been demonstrated the batter efficiency of the cupferron for determining all the Impurities. Detection limits range from 0.01 to 0.2 ppm., depending on the element, for samples 4 g in weight. An automatic spectrometer attached to a 16 K minicomputer and X-ray tube with a gold anode (2250-2700 W) are used. The Interferences between the lines ZrK{alpha} (2{sup n}d order) - HfL{alpha} and TiK{beta} - VK {alpha} have been studied and the respective correction coefficients have been deduced. (Author) 8 refs.

  14. Neutron activation analysis and activity in the vessel steel of a BWR reactor for their study without radiological risks in microscopy and spectrometry; Analisis de activacion neutronica y actividad en el acero de la vasija de un reactor nuclear tipo BWR para su estudio sin riesgos radiologicos en microscopia y espectrometria

    Energy Technology Data Exchange (ETDEWEB)

    Moranchel, M.; Garcia B, A. [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Fisica, Unidad Profesional Adolfo Lopez Mateos, Zacatenco, 07738 Mexico D. F. (Mexico); Longoria G, L. C., E-mail: mmoranchel@ipn.mx [IAEA, Department of Technical Cooperation, Division for Latin America, Room B1109 Wagramerstrasse 5, PO Box 100, A-1400, Vienna (Austria)

    2012-07-01

    The vessel material of nuclear reactors is subject to irradiation damage induced by the bombardment of neutrons coming from the reactor core. Neutrons are classified as fast and thermal, which produce different effects. Fast neutrons cause damage to the material by dislocation or displacement of atoms in the crystal structure, while the effect of thermal neutrons is a nuclear transmutation that can significantly change the properties of the material. The type and intensity of damage is based on the characteristics of the material, the flow of neutrons and the modes of neutrons interaction with the atomic structures of the material, among others. This work, alluding to nuclear transmutation, makes an analysis of neutron activation of all isotopes in a steel boiling water nuclear reactor (BWR) vessel. An analytical expression is obtained in order to model activity of steel, on the basis of the weight percentage of its atomic components. Its activity is theoretically estimated in a witness sample of the same material as that of the vessel, placed within the nuclear reactor since the beginning of its commercial operation in April 1995, up to August 2010. It was theoretically determined that the witness sample, with a 0.56 g mass (1 x 1 x 0.07 cm{sup 3} dimensions or equivalent) does not present a radiological risks during the stage of preparation, observation and analysis of it in electron microscopy and X-ray diffraction equipment s. The theoretical results were checked experimentally by measuring the activity of the sample by means of gamma spectrometry, measurement of the exposure levels around the sample, as well as the induced level to whole body and limbs, using thermo-luminescent dosimetry (TLD). As a result of the theoretical analysis, new chemical elements are predicted, as a result of the activation phenomena and radioactive decay, whose presence can be a fundamental factor of change in the properties of the vessel. This work is a preamble to the investigation of the damage of neutron irradiation on the vessel steel of boiling water reactors (BWR) using electron microscopy, spectroscopy and X-ray diffraction techniques. (Author)

  15. XRD (X-Ray Diffraction) and nitrogen adsorption characterization of Ni-Pt/mordenite catalysts; Caracterizacao por EDX (Espectrometria de Raios-X), DRX (Difracao de Raios-X) e adsorcao de nitrogenio de catalisadores Ni/Pt/mordenita visando sua aplicacao na isomerizacao de n-hexano

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Geovana do Socorro V.; Sousa, Bianca V.; Rodrigues, Meiry Glaucia F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2008-07-01

    The search for molecules of high octane arose great interest in the isomerization processes. Catalysts to the zeolite base have been wide developed for the n-paraffins isomerization. In this work, bimetallic bifunctional catalysts supported on Mordenite zeolite were prepared samples containing 60Pt40Ni (wt.%) metal (Pt). The catalysts were obtained by competitive ion exchange using aqueous solutions of [Pt(NH{sub 3}){sub 4}]Cl{sub 2} and Ni(NH{sub 3}){sub 6}]Cl{sub 2} complexes. The EDS characterization analyses showed incorporation of the nickel and platinum mordenite zeolite. The diffractograms showed competitive ion exchange and calcination processes did not provoke appreciable changes in the zeolitic support framework. The peaks attributed to nickel and platinum oxides was possible to observe in the bimetallic catalysts 60Ni40Pt/MOR. The results of the N{sub 2} physical adsorption of the 60Ni40Pt/MOR showed that it did not have modification in the superficial area of the catalysts. (author)

  16. Aerial gamma spectrometry of the uranium province of Lagoa Real (Caetite, BA, Brazil): go environmental aspects and distribution of the absorbed dose in the air; Espectrometria gama aerea da provincia uranifera de Lagoa Real (Caetite, BA): aspectos geoambientais e distribuicao da dose absorvida no ar

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Esau Francisco Sena

    2006-07-01

    In the present study, it was analyzed the surface concentrations of the natural radioelements K, U and Th, as well as the absorbed dose rate in air caused by gamma radiation from the Lagoa Real uranium province, which is located at the center southern portion of Bahia State and comprises an area of approximately 4.600 Km{sup 2}. Data from the airborne gamma ray spectrometric survey of the region (Sao Timoeo Project) carried out in 1979, was used in this study. Besides, recent data of U, Th and absorbed dose rates from the Environmental Monitoring Program of the uranium concentration plant (URA), operated in the region by the Brazilian Nuclear Industries (INB), were used with the aim of inter compare the sampling points in the same geo referenced area. Imaging geo processing software's give support to frame maps of surface concentrations and ternary maps, as well as allow the integration of these with other themes (e.g. hydrology, geology, pedology) favouring the interpretation of geo environmental process from the radioactive cartography. Considering the whole study area, it was obtained the following mean values: absorbed dose rate in air (61,08 nGy.h{sup -1}), Potassium (1,65 % K) , Uranium (3,02 ppm eU) and thorium (18,26 ppm eTh). The geological unities bounding the uranium anomalies were placed in the areas characterized by the highest values of radioelements and, as expected, the major dose levels. The use of ternary maps coupled with the geology and hydrology allowed distinguishing the relationship between the surface distribution of natural radioelements and the geo environmental aspects, including the influence of the catchment in their transport and migration. (author)

  17. Study of New Analytical Methodologies for the Analysis of Polychlorinated Dibenzo-P-Dioxins (PCDDs) and Polychlorinated Di benzofurans (PCDFs) by Quadrupole Ion Storage Tandem-in-time Mass Spectrometry. Application to Environmental Samples; Estudio de nuevas metodologias analiticas en la determinacion de policlorodibenzo-P-dioxinas (PCDDs) y policlosrodibenzofuranos (PCDFs) por espectrometria de masas con trampa ionica. Aplicacion a muestras medioambientales

    Energy Technology Data Exchange (ETDEWEB)

    Sanz Chichon, M. P.

    2008-07-01

    Two alternative analytical methodologies have been developed for the analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and di benzofurans (PCDFs) in environmental samples. The techniques studied have been: Pressurized Fluid Extraction (PFE) and Microwave-Assisted Extraction (MAE) versus Soxhlet extraction; the automated system Power-PrepTM versus the conventional cleanup using open chromatographic columns with different adsorbents and the application of tandem mass spectrometry (HRGC-MS/MS) versus high resolution mass spectrometry (HRGC-HRMS) for PCDD/Fs detection and quantification. (Author) 233 refs.

  18. Application of neutron activation techniques and x-ray energy dispersion spectrometry, in analysis of metallic traces adsorbed by chelex-100 resin; Ativacao das tecnicas de ativacao neutronica e espectrometria por dispersao de onda e de energia de raios X, na analise de tracos metalicos adsorvidos pela resina chelex-100

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Jair C.; Amaral, Angela M.; Magalhaes, Jesus C.; Pereira, Jose S.J.; Silva, Juliana B. da; Auler, Lucia M.L.A. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)]. E-mail: jcf@urano.cdtn.br

    2000-07-01

    In this work, the authors have investigated optimal conditions of adsorption for several ion metallic groups (cations of heavy metals and transition metals, oxyanions metallics and metalloids and cations of rare earths), as traces (ppb), withdrawn and in mixture of groups, by chelex-100 resin. The experiments have been developed by bath techniques in ammonium acetate tamponade solution 40 mM pH 5,52 content 0,5 g of chelex-100 resin. After magnetic agitation for two hours, resins were dried and submitted to X-ray energy dispersion spectrometry, x-ray fluorescence spectrometry and neutron activation analysis. The results have demonstrated that chelex-100 resin adsorb quantitatively transition element groups and rare earth groups in two cases (withdrawn and simultaneously adsorption)

  19. Assessment of beta-emitter radionuclides in biological samples using liquid scintillation counting. Application to the study of internal doses in molecular and cellular biology techniques; Evaluacion en muestras biologicas de radionucleidos emisores beta mediante espectrometria de centelleo en fase liquida. Aplicaciones al estudio de dosis internas en tecnicas de investigacion de biologia molecular y celular

    Energy Technology Data Exchange (ETDEWEB)

    Sierra, I.; Delgado, A.; Navarro, T.; Macias, M. T.

    2007-07-01

    The radioisotopic techniques used in Molecular and Cellular Biology involve external and internal irradiation risk. It is necessary to control the possible internal contamination associated to the development of these techniques. The internal contamination risk can be due to physical and chemical properties of the labelled compounds, aerosols generated during the performance technique. The aim of this work was to estimate the possible intake of specific beta emitters during the technique development and to propose the required criterions to perform Individual Monitoring. The most representative radioisotopic techniques were selected attending their potential risk of internal contamination. Techniques were analysed applying IAEA methodology according to the used activity in each technique. It was necessary to identify the worker groups that would require individual monitoring on the base of their specific risk. Different measurement procedures were applied to study the possible intake in group risk and more than 160 persons were measured by in vitro bioassay. (Author) 96 refs.

  20. Determinação direta de selênio em água de coco e em leite de coco utilizando espectrometria de absorção atômica com atomização eletrotérmica em forno de grafite Direct determination of selenium in coconut water and coconut milk using graphite furnace atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Poliana C. Aleixo

    2000-06-01

    Full Text Available Selenium is both essential and toxic to man and animals, depending on the concentration and the ingested form. Most fruits and vegetables are poor sources of selenium, but coconut can be a good selenium source. Samples were suspended (1 + 4 v/v in a mixture of tertiary amines soluble in water (10% v/v CFA-C. This simple sample treatment avoided contamination and decreased the analysis time. The standard additions method was adopted for quantification. The action of the autosampler was improved by the presence of the amines mixture in the suspension. A Varian model AA-800 atomic absorption spectrometer equipped with a graphite furnace and a GTA 100 autosampler was used for selenium determination in coconut water and coconut milk. Background correction was performed by means of the Zeeman effect. Pyrolytically coated graphite tubes were employed. Using Pd as chemical modifier, the pyrolysis and the atomization temperatures were set at 1400 and 2200ºC, respectively. For six samples, the selenium concentration in coconut water varied from 6.5 to 21.0 mug L-1 and in coconut milk from 24.2 to 25.1 mug L-1. The accuracy of the proposed method was evaluated by an addition-recovery experiment and all recovered values are in the 99.5-102.3% range. The main advantage of the proposed method is that it can be directly applied without sample decomposition.

  1. Eletrodeposição de irídio em tubo de grafite como modificador químico permanente em espectrometria de absorção atômica Electrodeposition of iridium in graphite tube as permanent chemical modifier in atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Juliana Naozuka

    2003-12-01

    Full Text Available A tubular electrochemical flow-cell for iridium deposition on the inner surface of pyrolytic graphite tube for permanent chemical modification is proposed. A transversal heated graphite tube was used as working electrode, a cylindrical piece of graphite inserted into the graphite tube as auxiliary electrode, and a micro Ag/AgCl(sat as reference electrode. Iridium solution in 1.0 mol L-1 HCl, flowing at 0.55 mL min-1 for 60 min was used to perform the electrochemical modification. The applied potential to the flow-cell was - 0.700 V vs Ag/AgCl. Scanning electron microscopy images were taken for thermal and electrochemical modified graphite surface in order to evaluate the iridium distribution. Selenium hydride trapping was used to verify the performance of the proposed permanent chemical modifier.

  2. Validation of an analytical method for the determination of total mercury in urine samples using cold vapor atomic absorption spectrometry (CV-AAS); Validacao de metodologia analitica para determinacao de mercurio total em amostras de urina para espectrometria de absorcao atomica com geracao de vapor frio (CV-AAS)

    Energy Technology Data Exchange (ETDEWEB)

    Guilhen, Sabine Neusatz

    2009-07-01

    Mercury (Hg) is a toxic metal applied to a variety of products and processes, representing a risk to the health of occupationally or accidentally exposed subjects. Dental amalgam is a restorative material composed of metallic mercury, which use has been widely debated in the last decades. Due to the dubiety of the studies concerning dental amalgam, many efforts concerning this issue have been conducted. The Tropical Medicine Foundation (Tocantins, Brazil) has recently initiated a study to evaluate the environmental and occupational levels of exposure to mercury in dentistry attendants at public consulting rooms in the city of Araguaina (TO). In collaboration with this study, the laboratory of analysis at IPEN's Chemistry and Environment Center is undertaking the analysis of mercury levels in exposed subjects' urine samples using cold vapor atomic absorption spectrometry. This analysis requires the definition of a methodology capable of generating reliable results. Such methodology can only be implemented after a rigorous validation procedure. As part of this work, a series of tests were conducted in order to confirm the suitability of the selected methodology and to assert that the laboratory addresses all requirements needed for a successful implementation of the methodology. The following parameters were considered in order to test the method's performance: detection and quantitation limits, selectivity, sensitivity, linearity, accuracy and precision. The assays were carried out with certified reference material, which assures the traceability of the results. Taking into account the estimated parameters, the method can be considered suitable for the afore mentioned purpose. The mercury concentration found for the reference material was of (95,12 +- 11,70)mug.L{sup -1} with a recovery rate of 97%. The method was also applied to 39 urine samples, six of which (15%) showing urinary mercury levels above the normal limit of 10{mu}g.L{sup -1}. The obtained results fall into a range of concentration from 1,02 to 23,36{mu}g.L{sup -1}. (author)

  3. Aerial gamma spectrometry of the uranium province of Lagoa Real (Caetite, BA, Brazil): go environmental aspects and distribution of the absorbed dose in the air; Espectrometria gama aerea da provincia uranifera de Lagoa Real (Caetite, BA): aspectos geoambientais e distribuicao da dose absorvida no ar

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Esau Francisco Sena

    2006-07-01

    In the present study, it was analyzed the surface concentrations of the natural radioelements K, U and Th, as well as the absorbed dose rate in air caused by gamma radiation from the Lagoa Real uranium province, which is located at the center southern portion of Bahia State and comprises an area of approximately 4.600 Km{sup 2}. Data from the airborne gamma ray spectrometric survey of the region (Sao Timoeo Project) carried out in 1979, was used in this study. Besides, recent data of U, Th and absorbed dose rates from the Environmental Monitoring Program of the uranium concentration plant (URA), operated in the region by the Brazilian Nuclear Industries (INB), were used with the aim of inter compare the sampling points in the same geo referenced area. Imaging geo processing software's give support to frame maps of surface concentrations and ternary maps, as well as allow the integration of these with other themes (e.g. hydrology, geology, pedology) favouring the interpretation of geo environmental process from the radioactive cartography. Considering the whole study area, it was obtained the following mean values: absorbed dose rate in air (61,08 nGy.h{sup -1}), Potassium (1,65 % K) , Uranium (3,02 ppm eU) and thorium (18,26 ppm eTh). The geological unities bounding the uranium anomalies were placed in the areas characterized by the highest values of radioelements and, as expected, the major dose levels. The use of ternary maps coupled with the geology and hydrology allowed distinguishing the relationship between the surface distribution of natural radioelements and the geo environmental aspects, including the influence of the catchment in their transport and migration. (author)

  4. Geração eletroquímica do hidreto de selênio em sistema de injeção em fluxo com detecção por espectrometria de absorção atômica com chama Ar-Glp

    Directory of Open Access Journals (Sweden)

    Machado Luís Fernando Rebel

    2000-01-01

    Full Text Available This paper presents a system for electrochemical hydride generation using flow-injection and atomic absorption spectrometry to determine selenium in biological materials. The electrolytic cell was constructed by assembling two reservoirs, one for the sample and the other for the electrolytic solution separated by a Nafion membrane. Each compartment had a Pt electrode. The sample and electrolyte flow-rates, acidic media, and applied current were adjusted to attain the best analytical performance and ensure the membrane lifetime. The atomisation system used a T quartz tube in an air-LPG flame. The composition of the flame, the observation height, and the argon flow rate used to carry the hydrides were critically investigated. The system allowed to perform thirty determinations per hour with a detection limit of 10 mug L-1 of Se. Relative standard deviations were in general lower than 1.5% for a solution containing 20.0 and 34.0 mug L-1 of Se in a typical sample digest. Accuracy was assessed analysing the certified materials: rice flour (NIST-1568 from National Institute of Standard and Technology and dried fish (MA-A-2, whole animal blood (A-2/1974 from the International Atomic Energy Agency.

  5. Gamma ray spectrometry and radon emissions in soils from the Piquiri Syenite Massif region (Encruzilhada do Sul e Cachoeira do Sul, RS); Espectrometria de raios gama e emissao de radonio em solos da regiao do Macico Sienitico Piquiri (Cachoeira do Sul e Encruzilhada do Sul, RS)

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Mujalli, Gibran, E-mail: gibran.romero.mujalli@uni-hamburg.de [Institute for Geology, University of Hamburg (Germany); Roisenberg, Ari, E-mail: ari.roisenberg@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Instituto de Geociencias. Departamento de Mineralogia e Petrologia

    2016-05-15

    This study was focused in performing a gamma radiation survey and measurements of radon concentration in soils from the Piquiri Syenite Massif, an intrusion located at central area of the Rio Grande do Sul State. This intrusion has alkaline affiliation with high concentrations of uranium in accessory minerals as zircon, sphene, apatite, and others. The gamma radiation measurements were made considering a grid with squares about 2 km side each, using the gamma spectrometer RS-125, obtaining counts per second (cps), dose rate (DR) and concentrations of K, eU and eTh. Moreover, measurements of {sup 220}Rn and {sup 222}Rn in soil were made using the AlphaGUARD equipment. The counts per second values obtained in this study range from 130 to 1045, the dose rate from 28.9 nSv/h to 424.6 nSv/h, the K concentration from 0.5 % to 8.3 %, the eU concentration from 0.8 ppm to 25.8 ppm, and the eTh concentration from 3.0 ppm to 99.2 ppm. The distribution of K defines with relatively precision the lithological contacts of the Piquiri Syenite Massif and between the two main facies of the intrusion (Main and Marginal Facies). The Main Facies of the syenite contains the highest concentrations of eTh, while the highest concentrations of eU were measured in the north area of this facies. The {sup 220}Rn and {sup 222}Rn concentrations range from 10 kBq/m{sup 3} to 550 kBq/m{sup 3} and from 5 kBq/m{sup 3} to 400 kBq/m{sup 3}, respectively, in the Main and Marginal Facies. The high values of radon measured in Main Facies of the Piquiri Syenite Intrusion may indicate high potential risk to the health of inhabitants in the area. (author)

  6. Determination of experimental conditions for the analysis of rare-earth elements by X-ray fluorescence spectrometry. Application to oxalates and potassium sulphate matrices; Establecimiento de varibles experimentales para la determinacion de tierras raras por espectrometria de fluorescencia de rayos X. Aplicacion a los concentrados de oxalatos y sulfatos

    Energy Technology Data Exchange (ETDEWEB)

    Bayon Fuentes, A.; Bermudez Polonio, J.

    1969-07-01

    A previous theoretical and experimental study is carried out in order to analyze the rare earths elements by X-ray florescence spectrometry. All possible spectral interferences are considered. The working conditions for each element were selected, taking into account the peak/background ratio values for the following parameters: tungsten, molybdenum and chromium targets, current and voltage, analyzing crystals, and scintillation and flow proportional counters. Calibration curves were plotted showing the concentration of rare earths elements in oxalates and potassium sulphate matrices, and the theoretical detection limits for each element: are calculated. (Author) 8 refs.

  7. Calibration of the High Resolution Gamma Spectrometry Detection Systems from the Environmental Radioactivity Unit and Radiological Surveillance (ARU and RV); Calibracion de los Sistemas Detectores de Espectrometria Gamma de Alta Resolucion de la Unidad de Radiactividad Ambiental y Vigilancia Radiologica (URA y VR)

    Energy Technology Data Exchange (ETDEWEB)

    Suarez-Navarro, J. A.; Gasco, C.; Arana, M.; Suanez, A.

    2012-11-01

    In accordance with international regulations and with the quality criteria imposed by the internal quality system of the laboratory of gamma spectrometry, which belongs to the Unit of Environmental Radioactivity and Radiation Monitoring (URA y VR), it is necessary to perform a periodic calibration of the measurement systems of gamma spectrometry. The equipment calibration carries with the need for the preparation of the geometries of measurement and calibration in energy and in efficiencies. This report reflects the procedures for the preparation of the wide range of geometries available in the laboratory, as well as the different calibrations performed with those geometries in almost all the laboratory gamma detectors using the CANBERRA software Genie 2k. (Author) 9 refs.

  8. Study on water-sediment interaction in samples from Rio das Velhas - Minas Gerais State - Brazil using instrumental neutron activation analysis, and argon plasma coupled mass spectroscopy; Estudo da interacao agua-sedimento em amostras do Rio das Velhas - MG utilizando os metodos: analise por ativacao neutronica instrumental (INAA) e espectrometria de massa acoplada a um plasma de argonio (ICP-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Veado, Maria Adelaide R.V.; Oliveira, Arno H. de [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Revel, G.; Pinte, G. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Lab. d`Analyse par Activation Pierre Sue; Toulhoat, P. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Unite Mixte de Recherche Analyse et Environnement

    1999-11-01

    Sorption of the metallic elements in aqueous solutions in surface of the hydroxides affects the transport of heavy elements in the freshwaters. Sorption and the chemistry of the hydroxides are important studies for knowledge in geology, waters and waste treatment, and environment studies. In the industrial mining region areas, the river surface waters are subject to modifications in its physical and chemistries properties: pH, DBO, conductivity and alkalinity. Instrumental neutron activation analysis and inductively coupled plasma-mass spectrometry (ICP-MS), have ben used for the determination of toxic heavy metals and others pollutants in the Das Velhas river in State of Minas Gerais, in south-east Brazil. Water samples were collected with acidification on site, which provoked a change of its natural pH. Consequently, metallic elements associated to hydroxides and to particles in suspension were liberated. The objective of this paper is to show the different behavior of any elements, in water of Das Velhas river, with relation of its chemical forms (cations or anions), the solubility degree, the pH and the presence of rare earth elements. (author) 11 refs., 10 figs.; e-mail: adelaide at nuclear.ufmg.br; heeren at nuclear.ufmg.br; grevel at drecam.cea.fr; pierre.toulhoat at cea.fr

  9. Teores de nutrientes minerais e metais pesados em açúcar mascavo produzido por diferentes sistemas orgânicos e convencionais

    OpenAIRE

    Paulo Dirceu Luchini

    2014-01-01

    Quantificou-se os teores de Cu, Zn, Mn, Fe, Pb e Cd em açúcar mascavo oriundo de canas produzidas por diferentes formas de cultivo de sistemas orgânicos e convencionais. Os metais Pb e Cd foram determinados por espectrometria de absorção atômica com atomização eletrotérmica em forno de grafite (GFAA) e os metais Cu, Zn, Mn e Fe foram determinados por espectrometria de absorção atômica com chama (FAAS). Os teores de Cu, Zn, Mn e Fe foram detectados apenas em valores abaixo do limite recomendad...

  10. Composition of essential oils from the leaves of six species of the Baccharis genus from 'campos de altitude' of the atlantic forest of Sao Paulo; Composicao quimica dos oleos essenciais das folhas de seis especies do genero Baccharis de 'campos de altitude' da Mata Atlantica Paulista

    Energy Technology Data Exchange (ETDEWEB)

    Lago, Joao Henrique G.; Romoff, Paulete; Favero, Oriana A. [Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil). Centro de Ciencias e Humanidades]. E-mail: joaolago@mackenzie.com.br; Soares, Marisi G.; Baraldi, Patricia T.; Correa, Arlene G. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil). Dept. de Quimica; Souza, Fatima O. [Instituto de Botanica, Sao Paulo, SP (Brazil). Secao de Curadoria do Herbario

    2008-07-01

    The essential oils from the leaves of six species of the Baccharis genus (B. dracunculifolia, B. microdonta, B. regnelli, B. schultzii, B. trimera, and B. uncinella), collected in the 'Campos de Altitude' of the Atlantic Forest (SP), were extracted using hydrodistillation procedures and analyzed by GC and GC/MS. There was a predominance of sesquiterpenes in all studied oils as {beta}-elemene in B. dracunculifolia and B. regnelli, {alpha}-humulene in B. trimera, {gamma}-gurjunene in B. schultzii, bicyclogermacrene in B. regnelli, {delta}-cadinene in B. regnelli and B. uncinella, spathulenol in B. schultzii, caryophyllene oxide in B. microdonta and guaiol in B. uncinella. However, a high amount of monoterpenes was also observed in B. uncinella ({alpha}-pinene), B. regnelli ({delta}-car-3-ene) and B. schultzii (limonene). The chemical compounds of the essential oils of B. schultzii, B. regnelli and B. microdonta are described for the first time in this work. (author)

  11. Biomimetic polymers in analytical chemistry. Part 1: preparation and applications of MIP (Molecularly Imprinted Polymers) in extraction and separation techniques; Polimeros biomimeticos em quimica analitica. Parte 1: preparo e aplicacoes de MIP ('Molecularly Imprinted Polymers') em tecnicas de extracao e separacao

    Energy Technology Data Exchange (ETDEWEB)

    Tarley, Cesar Ricardo Teixeira; Sotomayor, Maria del Pilar Taboada; Kubota, Lauro Tatsuo [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica. Dept. de Quimica Analitica]. E-mail: kubota@iqm.unicamp.br

    2005-11-15

    MIPs are synthetic polymers that are used as biomimetic materials simulating the mechanism verified in natural entities such as antibodies and enzymes. Although MIPs have been successfully used as an outstanding tool for enhancing the selectivity or different analytical approaches, such as separation science and electrochemical and optical sensors, several parameters must be optimized during their synthesis. Therefore, the state-of-the-art of MIP production as well as the different polymerization methods are discussed. The potential selectivity of MIPs in the extraction and separation techniques focusing mainly on environmental, clinical and pharmaceutical samples as applications for analytical purposes is presented. (author)

  12. Microbiological, physicochemical and sensory evaluation of cabbage and carrot minimally processed salad after radiation treatment intended to immunocompromised patients or with special diets; Avaliacao microbiologica, fisico-quimica e sensorial de salada de repolho com cenoura minimamente processada apos o tratamento por radiacao gama destinado a pacientes imunocomprometidos ou com dietas especiais

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Thaise Cristine Fernandes

    2015-09-01

    During and after the treatment of cancer, people with HIV or transplants, the food intake can offer a well-being to the patient, because the action of eating right helps people to feel strong. Healthy people have their immune system working properly and can tolerate small amounts of bacteria. However, immunocompromised persons may not be able to and however immunocompromised people cannot fight this small amount of microorganisms and require a diet with very low microbiological count to avoid contact with potentially harmful bacteria. This is called neutropenic diet. These patients are susceptible to food contamination, so that it's not advisable the ingestion of raw products. The vegetable irradiation with low doses has the purpose of reducing the microbial load. The aim of this study was to obtain data on microbiological, sensorial e physicochemical aspects in minimally processed 'Primavera' salad irradiated with different doses of gamma radiation designed to immunocompromised patients. It were used doses of 1.0kGy, 2.0kGy, 3.0kGy and 4.0kGy irradiated in the Multipurpose Irradiator {sup 60}Co located in Radiation Technology Center. Microbiological analyzes were performed (n=25) using Petrifilm, sensory analysis using the sensory acceptance test (n=30) and triangular (n=15) and texture analysis (n=90) in the Food Microbiology Laboratory located at the Radiation Technology Center. The texture analysis was performed with the aid of a texturometer equipped with 5 kg load cell using a triangular cutting Warner-Bratzler Knife blade probe with the descent speed of 2mm/sec. All results were expressed in Newtons (N). The results showed that for microbiological analyzes the standards were followed according to the RDC 12/01 ANVISA. For the sensory test of acceptation no difference was found among the samples, however in the triangular test could be found slight differences between samples irradiated with 4.0kGy and control and there was significant difference among the sample, showing that the sample of 3.0kGy would be indicate for this specific public. It can be concluded that for a neutropenic diet the suggested dose is 2.0kGy. (author)

  13. Chemical species of europium (III) in ionic force media 0.02M, 0.1M, and 0.7M NaClO{sub 4} at 298 K; Especies quimicas del europio (III) en medios de fuerza ionica 0.02M, 0.1M y 0.7M NaClO{sub 4} a 298 K

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez R, E.; Jimenez R, M.; Solache R, M. [Instituto Nacional de Investigaciones Nucleares, Departamento de Quimica, A.P. 18-1027, C.P. 11801 Mexico D.F. (Mexico)

    2000-07-01

    In order to know the effects of the controlled or accidental liberation of the europium in the environment, it is necessary to know its chemical behavior in found conditions in oceans, ground and surface water. The behavior of this element in these environments can be controlled mainly by the hydrolysis and its interaction with inorganic and organic ions. (Author)

  14. Spectrographic determination of boron and silicon in uranium tetrafluoride: Study of the chemical reactions in the electrode cavity when ZnO is used as a uranium excitation suppressor; Determinacion espectrografica de Boro y Silicio en Tetrafluoruro de Unraio: Estudio de las reacciones quimicas que tienen lugar en el crater del electrodo al autilizar ZnO como supresor de la excitacion del Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Alduan, F. A.; Capdevila, C.; Rosa, M.

    1973-07-01

    A method has been developed for determining traces of boron and silicon in uranium tetrafluoride. Use is made of zinc oxide to decrease the volatilization of uranium and achieve high sensitivities. The thermochemical reactions which occur in the anode cavity during the arcing process have been investigated. UO{sub 2} and a uranium, zinc and fluorine compound, both less volatile than uranium tetrafluoride, are formed. (Author)

  15. Evaluation of the ionizing radiation {sup 60}Co effect on the physical, chemical and nutritional properties of different cultivars of soybean grains (Glycine max (L.));Avaliacao dos efeitos da radiacao ionizante de {sup 60}Co em propriedades fisicas, quimicas e nutricionais de diferentes cultivares de graos de soja Glycine max (L.)

    Energy Technology Data Exchange (ETDEWEB)

    Toledo, Tais Carolina Franqueira de

    2006-07-01

    With the increase of the world population, creative strategies will be necessary to control food production. To achieve this challenge, new cultivars have been development, though different techniques and characteristics. To improve food conservation, a plant of methods can be used. The use of Cobalto-60 radiation is a secure and useful method to increase the life time of foods. Due to the commercial and nutritional importance of soybean, some alterations must be studied. This study has the objective to determinate this alterations caused by irradiation (with doses of 2, 4 and 8 kGy) in raw and cooked grain of five different cultivars of soybean (BRS 212, BRS 213, BRS 214, 231 BRS and E48), this study includes analysis of time cooking and hydratation, and chemical analysis of proximate composition, in vitro digestibility of proteins, percentage of deamidation , phenolics compounds, trypsin inhibitors and tannins. The amount of water absorbed by each grain varied from 14.00 to 16.66mL, and the time cooking varied from 119.67 to 291.33 minutes. The values found for ash were 4.90 to 6.08%, for protein from 21.23 to 36.99%, for fat from 19.22 to 24.84%, soluble staple fibres from 1.37 to 4.03% and insoluble staple fibres from 15.97 to 18.87%. The deamidation percentage in the different samples varied of 17,34 to 57.79% and the digestibility in vitro from 84.45 to 89.11%. Inside of the anti nutritional factors, the total compounds phenolics varied from 3.9 to 9.7 mg/g, the units of trypsin inhibited from 24.75 to 57.53 UTI/g and the tannins from 0.02 to 0.32 mg/g. For the physical analyses it showed differences in the time of hydratation among them and the irradiation promoted reduction in the time, but not in the amount of absorbed water; in the cooking time it had reduction with the increase of the doses of radiation; the differences found in the proximate composition did not have influence with the irradiation, but with the different cultivars; for the digestibility alterations only with the cooking treatment had been found, showing an increase after the baking; the treatment of irradiation promoted a higher percentage of deamidation of the samples with the increase of the doses; regard to the anti nutritional factors, all them had a reduction as the doses radiation increased. The cooking also promoted a reduction in the anti nutritional factors in the raw and baked samples. So the treatment of irradiation did not promote reduction in the nutritional qualities of the soybean grains, being effective in the improvement of them with the reduction in the anti nutrient factors. (author)

  16. Caracterização físico-quimica de farinhas oriundas de variedades de mandioca utilizadas no vale do Juruá, Acre Physicochemical characteristics of flours deriving of cassava varieties used in the Vale do Juruá, Acre

    Directory of Open Access Journals (Sweden)

    Joana Maria Leite de Souza

    2008-12-01

    Full Text Available Algumas características de farinha de mandioca dependem da variedade da raiz utilizada para o processamento. Objetivou-se avaliar as características físico-químicas da farinha de mandioca oriundas de variedades utilizadas no estado do Acre. Os tratamentos foram compostos pelas variedades: T1= Paxiubão, T2= Im221, T3 = Caboquinha, T4 = Araçá, T5 = Colonial, T6 = Branquinha, T7 = Panati e T8 = Mansa e Brava. Foram coletadas amostras das oito variedades de mandioca em casas-de-farinha no município de Cruzeiro do Sul, Acre. As raízes foram transportadas via aérea para o Laboratório de Tecnologia de Alimentos da Embrapa-AC, na cidade de Rio Branco, Acre. Foram avaliados: teor de umidade, cinzas, lipídios, proteína, fibra bruta, carboidratos, acidez, pH e atividade de água. Todas as amostras se apresentaram de acordo com os padrões estabelecidos pela Legislação Brasileira para farinha de mandioca quanto ao teor de umidade, cinzas e carboidratos. As farinhas analisadas apresentam teores baixos de fibras e baixa acidez. A atividade de água das farinhas analisadas esteve abaixo do limite mínimo capaz de permitir o desenvolvimento de microrganismos. As variedades Araçá, Colonial e Branquinha se mostraram adequadas para a fabricação de farinha de mandioca devido, principalmente, ao elevado teor de proteína e carboidratos presente nas farinhas produzidas.Some characteristics of the cassava depend on the variety used for the processing. The objectified of this study was to evaluate physicochemical characteristics of the cassava flour from varieties used in Acre. The treatments were composed by the varieties: T1 = Paxiubão, T2 = Im221, T3 = Caboquinha, T4 = Araçá, T5 = Colonial, T6 = Branquinha, T7 = Panati and T8 = Mansa e Brava. Samples of flour of eight cassava varieties were collect in cassava mils in Cruzeiro do Sul. The samples were sent by airmail to Rio Branco, Acre, to be analyzed in the Food and Technology Laboratory at Embrapa-AC. The evaluated parameters were: water percentage, ashes, lipids, protein, fiber, carbohydrates, acidity, pH and water activity. All samples were taken according to the established patterns of the Brazilian Legislation for cassava flour, considering water percentage, ashes and carbohydrates. The analyzed flours presented low fibers levels and low acidity. The water activity of the analyzed flours was below the minimum limit necessary to allow microorganisms development. The varieties Araçá, Colonial and Branquinha were adequate to cassava flour manufacturing, mainly because of the high protein and carbohydrates levels present in the produced flour.

  17. "Sustancia" en el devenir la quimica: dime cómo te buscan y te diré que eres "Substance" in the evolution of chemistry: tell me how the other is looking for you and I will tell you what you are

    Directory of Open Access Journals (Sweden)

    Berta Lucila Henao

    2009-01-01

    Full Text Available Con base en planteamientos de Stephen Toulmin se presentan algunos aspectos del devenir histórico de la Química, en relación con el concepto sustancia. En un recorrido somero y no lineal, el texto intenta mostrar algunas complejas redes que se tejen entre los diversos componentes de lo que Toulmin denomina "ecología intelectual"; así como los nichos de la racionalidad y la representación, en las dinámicas de la misma. Esta aproximación al devenir del concepto, permite identificar preguntas y problemas que, con diferentes significados, énfasis y matices, aún están vigentes; modelos explicativos con los que se ha pretendido dar respuesta a dichas cuestiones y algunas formas de validación que permiten la aceptación contextual de los mismos. Finalmente, proponemos posibles implicaciones de estos análisis para la enseñanza.Taking into account Stephen Toulmin´s approaches, we will look at some aspects in the historical development of Chemistry connected to the concept of substance. In a superficial and non-linear manner, the text tries to show some complex networks that developed between the diverse components named by Toulmin as "intellectual ecology", such as the niches of rationality and the representations among them. This aproximation to the outcoming allows to identify the questions and the problems which with different meanings, emphasis and shades are still current; explanatory models which have pretended giving an answer to those questions and some forms of validity which permit the contextual acceptance of them. Finally, we propose possible implications of these analysis to teaching.

  18. Effect of addition of lignin in physical-chemical properties of a polyesters based on glycerol, phthalic and adipic acids; Efeito da adicao de lignina nas propriedades fisico-quimicas de poliesteres a base de glicerol e acidos ftalico e adipico

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, D.H.; Viana, A.P.M.; Lima, A.S.C.; Goncalves, A.P.B.; Miranda, C.S.; Jose, N.M., E-mail: dhanseng@yahoo.com.br [Universidade Federal da Bahia (UFBA), alvador, BA (Brazil)

    2014-07-01

    In this paper the study of different addition amounts of lignin in the physicochemical properties of polyesters made from glycerol and different amounts of phthalic and adipic acids have been proposed. The following characterizations were made: XRD, FTIR, TGA, DSC and SEM. The variation in the percentage of adipic and phthalic acids had a direct effect on thermal and morphological properties. The thermal analysis showed that there was miscibility between the polyester and lignin, by means of displacement related to the temperature of thermal degradation events. In FTIR analysis was noted displacements of characteristic bands of hydrogen bonds and specific carbonyl ester groups. These shifts were more pronounced as it has larger amounts of phthalic acid as monomer and larger amounts of lignin in the compositions. (author)

  19. Ionizing radiation effects of Cobalt-60 on the physical-chemical, sensorial and microbiological of bread with addition of linseed (Linum usitatissimum); Efeitos da radiacao ionizante de cobalto-60 nas caracteristicas fisico-quimicas sensoriais e microbiolgicas de paes com adicao de linhaca (Linum usitatissimum)

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Neila Camargo de

    2011-07-01

    The incorporation of functional ingredients on breading products has grown very much lately, because of the preoccupation with the consumers' health. The linseed has awakened the interest by its high level of fiber, lignin, omega-3 and antioxidants compounds. The objective of the present work is evaluate the ionizing radiation effect of {sup 60}Co on the physical-chemical, sensorial and microbiological characteristics of bread with addition of different concentration of brown linseed. There were elaborated 3 types of bread: French roll, form bread prepared with the mixture and form bread produced with conventional ingredients. It was added smashed brown linseed on the bread dough, with concentrations of 8% and 12%. After the preparation, the three kinds of bread packed with polypropylene packages and taken to the IPEN/USP (Institute of Nuclear Energetic Research/University of São Paulo) and irradiated with doses of 6, 8 and 10 kGy. Treatments were elaborated without the addition of linseed and without irradiation, for control, totalizing 12 distinct treatments, to each bread formula tested. Chemical analyses were made (centesimal composition, anti-nutritional compounds, anti-oxidant activity, glycemic index, fat acids, complex B vitamins and minerals); physical analyses (cooking index, volume, color and water activity); sensorial analyses (preference tests and Descriptive Quantitative Analysis - ADQ); microbiological analysis and a survey about irradiated products. It could be seen that the addition of linseed was efficient to increase the level of alimentary fiber and the level of lipids on the 3 bread formula. The three kinds of bread that received the linseed addition and that were not irradiated presented increase on the level of total phenolic; however, when the samples which received the linseed addition were submitted to the irradiation process, it could be noticed the decrease of the antioxidant capacity. There was an increase on the level of omega-3, depending on the percentage of linseed added to the bread. The linseed addition was effective to raise the level of potassium, phosphorus and magnesium. But, the irradiation decrease the level of vitamin B1 and vitamin B6 of the three kinds of bread. The irradiation did not influence the quality of the obtained bread. The sample tasters, not trained, accepted the bread independently of the doses of applied radiation. The ADQ test evidenced that the sensorial characteristics of the samples depend on the ingredient variation used on the formulas and on the radiation. The irradiated samples presented mold counting considerably lower than the non-irradiated samples, which increased the shelf-life of those products. The survey reveals that the majority of the people interviewed has little or any knowledge about radiation and believe that the irradiation can generate some kind of harm for human beings. Therefore, the bread production enriched with mashed linseed and submitted to gamma radiation is promising, given that the chemical and sensorial properties were considered satisfactory, besides the increasing of the shelf-time. (author)

  20. Chemical recycling of post-consumer PET: structural characterization of terephthalic acid and the effect of Alkaline Hydrolysis at low temperature; Reciclagem quimica do PET pos-consumo: caracterizacao estrutural do acido tereftalico e efeito da hidrolise alcalina em baixa temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Talitha Granja; Almeida, Yeda Medeiros Bastos de; Vinhas, Gloria Maria, E-mail: gmvinhas@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Quimica

    2014-09-15

    Due to the environmental impact caused by PET packaging disposal, this material recycling has been thoroughly discussed and evaluated. In particular, chemical recycling enables achievement of the monomers that are used in PET resin manufacture: ethylene glycol (EG) and terephthalic acid (PTA). Therefore, studies for this process optimization are important from environmental and economic points of view. The present study investigated certain parameters that influence the depolymerization reaction of PET post-consumer via alkaline hydrolysis in order to obtain PTA. Assays were performed at 70 °C by varying the concentration of sodium hydroxide and the reaction time. The best results were obtained at 10.82 mol L{sup -1} NaOH and 9 h reaction time. Consequently, it was possible to prove this process viability, once analyses by infrared and nuclear magnetic resonance confirmed that PTA was obtained in all reactions performed. (author)

  1. Preparation and characterization of phase-pure anatase and rutile TiO{sub 2} powder by new chemistry route; Preparacao e caracterizacao de nanoparticulas de TiO{sub 2} nas fases anatase e rutila por uma nova rota quimica

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, E. A.; Montanhera, M.A.; Paula, F.R., E-mail: sevlarede2@yahoo.com.br [Universidade Estadual Paulista Julio de Mesquista Filho (UNESP), Ilha Soltiera, SP (Brazil). Faculdade de Engenharia. Departameinto de Fisica e Quimica; Spada, E.R. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Institutlo de Fisica

    2014-07-01

    Titanium dioxide (TiO{sub 2}) is used in a wire range applications such as photocatalysis and sensor device. In this work is shown a new and effective method for the preparation of TiO{sub 2} nanocrystalline in the crystallographic forms, anatase and rutile. The method involves dissolving the TiOSO{sub 4} powder in H{sub 2}O{sub 2} solution and thermal treatment of amorphous precipitate. The technique of X-ray diffraction was used to follow the structure evolution of amorphous precipitate. Pure anatase structure and rutile are obtained at 600 deg C and 1000 deg C with a grain size estimated 24 and 55 nm respectively. TiO{sub 2} nanoparticles is a promising alternative of the low cost whose potential for solar cells deserve a careful evaluation, especially in hybrid solar cells that employs TiO{sub 2} as electron acceptor and as transport channels. (author)

  2. Measurement of the mass of mercury in electrolytic cells of Chemical Industry of the Istmo s. a. of c. v. Coatzacoalcos Plant, Ver. (Mexico); Determinacion de la masa de mercurio en celdas electroliticas de Industria Quimica del Istmo s. a. de c. v. Planta Coatzacoalcos, Ver

    Energy Technology Data Exchange (ETDEWEB)

    Angeles C, A.; Vizuet G, J.; Herrera M, J. M.; Flores M, J

    2001-01-15

    For the industry of the production of caustic soda and chlorine is commonly use electrolytic cells with mobile electrode of mercury; in the process it gets lost mass, and there is necessity to know the quantity of mercury that exists in each cell. To know the periodic levels of mercury in the 40 electrolytic cells of the Plant of Coatzacoalcos, in the State of Veracruz (Mexico), the investigators of the ININ used the technique of isotopic dilution by mean of the radioactive injection of a radioactive tracer.(Author)

  3. Effects of gamma radiation ({sup 60}Co) on the main physical and chemical properties of health care packaging and their compounds paper and multilayer plastic film, used for health products sterilization; Efeitos da radiacao gama (Cobalto-60) nas principais propriedades fisicas e quimicas da embalagens compostas por papel grau cirurgico e filme plastico laminado, destinadas a esterilizacao de produtos para saude

    Energy Technology Data Exchange (ETDEWEB)

    Porto, Karina Meschini Batista Geribello

    2013-07-01

    Gamma radiation is one of the technologies applied for the sterilization of packaging systems containing products for health. During sterilization process it is critical that the properties of packages are maintained. In this study two samples of commercial pouch packaging comprised of surgical grade paper on one side and the other side multilayer plastic film were irradiated with gamma rays. The following doses were applied 25 kGy (1,57 kGy/h) and 50 kGy (1,48 kGy/h). One packaging sample was paper formed by softwood fibers and multilayer plastic film based on poly(ethylene terephthalate) (PET)/polyethylene (PE). The second type of paper sample was made by a mixture of softwood and hardwood fibers and multilayer plastic film based on polyethylene terephthalate (ethylene) (PET)/polypropylene (PP). The effects of radiation on the physical and chemical properties of papers and multilayer plastic films, as well as the properties of the package were studied. The paper was the more radiation sensitive among the studied materials and radiation effects were more pronounced at brightness, pH, tearing resistance, bursting strength and tensile strength. Nonetheless, worst comparatively effects were noted on the sample made by a mixture of softwood and hardwood fibers. The porosity of paper was enhanced by 50 kGy. In the case of plastic films, radiation effects on tensile strength was the most pronounced property for both samples. In the case of the packaging the sealing resistance decreased with radiation. The effects observed for the treatment at 50 kGy were more pronounced when compared to 25 kGy. This last is the dose which is usually applied to sterilize health products. A dosimetry study was performed during irradiation at 25 kGy, 40 kGy and 50 kGy and its importance may be reported by the average dose variation 20 %. (author)

  4. Verification of the correlation between the {sup 210} Pb and the chemical composition of the incrustations found on gas pipelines and the implication on radiological protection; Verificacao da correlacao entre a atividade de {sup 210}Pb e a composicao quimica de incrustacoes encontradas em linhas de gas e a implicacao em protecao radiologica

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Franciane Martins de Carvalho

    2004-07-01

    In the last decades, the occurrence of solid residual deposits, known as black powder, in natural-gas pipelines, gathering systems and compression equipment from gas industries has raised increasing regulatory concerns in terms of radiological protection. Concerns are also raised about the waste disposal and management of the radioactive residues eventually produced. Recent projections indicate a significant increase in the production of natural-gas and its products, due to a growing commercial demand, which leads to the production of huge amounts of residues. Thus, more information is needed in order to allow a preliminary evaluation of the radiological profile of this type of industry. In black powder residues, the most prevalent radioisotope is {sup 210}Pb. The present work aimed to investigate the correlation between the chemical composition of the residue and the concentration of {sup 210}Pb, in black powder samples collected at Bacia de Campos, in the State of Rio de Janeiro, Brazil. The main objective was to generate information to regulatory authorities, to the National Commission of Nuclear Energy (CNEN) and to companies that produce natural-gas, such as PETROBRAS. Based on the information, the gas producing companies could elaborate radiological protection guidelines, and also decide about the need for implementation of a waste management program at the installation. The samples of black powder analyzed at the present work have confirmed the existence of such correlation between the concentration of {sup 210}Pb and chemical parameters. In principle, the present results make the use of such correlation feasible for preliminary evaluations of the {sup 210}Pb levels in natural-gas installations. On the other hand, given the geographic limitations, a broader study is recommended, in order to evaluate the investigated correlation, which could be used as a guiding tool for the Brazilian industry of production and processing of natural-gas.(author)

  5. Recent Developments in the Chemical Thermodynamics of the Uranium Chalcogenides; Progres Accomplis Recemment dans la Thermodynamique Chimique des Chalcogenures d'Uranium; Poslednie dostizheniya v khimicheskoj termodinamike khal'kogenidov Urana; Recientes Progresos en la Termodinamica Quimica de los Calcogenidos de Uranio

    Energy Technology Data Exchange (ETDEWEB)

    Westrum, Jr., E. F. [University of Michigan, Ann Arbor, MI (United States)

    1966-02-15

    Extension of the cryothermal data on tetrauranium enneaoxide to higher temperatures has revealed the thermophysical aspects of the (suspected) gradual, {lambda}-type, structural transition at 348 Degree-Sign K with an associated entropy increment of 1.84 cal/gfm Degree-Sign K involved in the displacement of interstitial oxygen atoms. Measurements of both heat capacity and magnetic susceptibility on Mallinckrodt sintered uranium dioxide have confirmed that the antiferromagnetic-paramagnetic transition occurs at 30.4 Degree-Sign K with a heat capacity of 400 cal/gfm Degree-Sign K rather than at 28.7 Degree-Sign K with 9 cal/gfm Degree-Sign K as reported in the literature. This now permits interpretation of the thermal anomaly found in {beta}-triuranium heptaoxide. Cryogenic heat capacities on well-characterized samples of {alpha}-, {beta}- and {gamma}-uranium trioxide prepared by Dr. E.H.P. Cordfunke of Reactor Centrum Nederland are combined with his higher temperature heat capacities, enthalpies of formation and other thermodynamic data to yield relative stability data for these important nuclear materials. Both uranium monoselenide and Uranium diselenide are found to have lambda-type anomalies associated with magnetic disordering. That in uranium diselenide occurs at 13.1 Degree-Sign K with an associated entropy increment of 0.16 cal/gfm Degree-Sign K. The 160 Degree-Sign K anomaly in the monoselenide has an entropy increment of 1.0 cal/gfm Degree-Sign K, which may be compared with the value of 1.17 found for the monosulfide near 180 Degree-Sign K. Both thermal anomalies in the monochalcogenides arise as a consequence of disordering the ferromagnetic state and contrast with the antiferromagnetic anomaly found in the isostructural mononitride at 52 Degree-Sign K. The new thermodynamic data accord well with the entropy estimation scheme of Gronvold and Westrum. (author) [French] L'extension de la temperature plus elevee des valeurs aux basses temperatures des constantes relatives au nonaoxyde de tetrauranium a revele les aspects thermophysiques de la transition structurale de ' type {lambda} supposee progressive a 348 Degree-Sign K avec accroissement d'entropie associe de 1,84 cal/gfm Degree-Sign K, qui intervient dans le deplacement d'atomes d'oxygene interstitiels. Des mesures de la capacite calorifique et de la susceptibilite magnetique sur du bioxyde d'uranium fritte de Mallincktodt ont confirme que la transition antiferromagnetique-paramagnetique se produit a 30,4 Degree-Sign K avec 400 cal/gfm Degree-Sign K pour la capacite calorifique et non a 28,7 Degree-Sign K avec une saute de 9 cal/gfm Degree-Sign K comme il est dit dans d'autres ouvrages. On peut ainsi interpreter l'anomalie thermique trouvee dans l'heptaoxyde de triuianium beta. L'auteur a combine les capacites calorifiques, aux basses temperatures, d'echantillons bien caracterises de trioxyde d'uranium alpha, beta et gamma prepares par E. Cordfunke du Reactor Centrum Nederland avec les valeurs des capacites calorifiques, des enthalpies de formation et d'autres constantes thermodynamiques pour en tirer les valeurs de la stabilite relative pour ces importants materiaux nucleaires. Il a constate que le mohoseleniure et le biseleniure d'uranium presentaient tous deux des anomalies du type lambda associees a un desordre magnetique. Cette anomalie se produit a 13,1 Degree-Sign K dans le biseleniure, avec un accroissement d'entropie associe de 0,16 cal/gfm Degree-Sign K. L'anomalie se produisant a 160 Degree-Sign K dans le monoseleniure est accompagnee d'un accroissement d'entropie de 1,0 cal/gfm Degree-Sign K, qui peut etre compare a la valeur 1,17 trouvee pour le monosulfure au voisinage de 180 Degree-Sign K. Les deux anomalies thermiques dans les monochalcogenures resultent d'un desordre de l'etat ferromagnetique et s'opposent b l'anomalie antiferromagnetique constatee dans le mononitrure isostructural a 52 Degree-Sign K. Les nouvelles valeurs des constantes thermodynamiques sont en bon accord avec le systeme d'estimation de l'entropie de Gronvold et Westrum. (author) [Spanish] La extension a temperaturas mas elevadas de los datos criotermicos correspondientes al U{sub 4}O{sub 11} ha puesto de manifiesto los aspectos termoffsicos de la transicion estructural gradual (sospechada) de tipo lambda a 348 Degree-Sign K, con un correspondiente aumento de entropia igual a 1,84 cal/gfm Degree-Sign K, vinculado al desplazamiento de atomos de oxigeno intersticiales. Las mediciones, de la capacidad calorifica y de la susceptibilidad magnetica, realizadas con UO{sub 2}'Mallinckrodt' sinterizado, confirmaron que la transicion antiferromagnetica-paramagnetica tiene lugar a 30,4 Degree-Sign K con una variacion de capacidad calorifica igual a 400 cal/gfm Degree-Sign K, en lugar de producirse a 28,7eK con una variacion de 9 cal/gfm eK, segun se informa en la literatura tecnica. Con ello se puede interpretar ahora la anomalia termica hallada en el U{sub 3}O{sub 7}-{beta}. La capacidad calorifica a bajas temperaturas de muestras bien caracterizadas de UO{sub 3}-{alpha}, UO{sub 3}-{beta} y UO{sub 3} -{gamma}, preparadas por el Dr. E.H.P. Cordfunke, del Reactor Centrum Nederland, se combina con estas capacidades calorificas a temperaturas mas elevadas, con las entalpias de formacion y con otros datos termodinamicos, para obtener datos de estabilidad relativa correspondientes a esos importantes materiales nucleares. Tanto el monoseleniuro como el diseleniuro de uranio poseen anomalias de tipo lambda vinculadas al desordenamiento magnetico. La del diseleniuro de uranio se produce a 13,1 Degree-Sign K, con un incremento de entropia igual a 0,16 cal/gfm Degree-Sign K. La anomalia de 160 Degree-Sign K tiene un incremento de entropia de 1,0 cal/gfm eK, que puede compararse con el valor 1,17 encontrado para el monosulfuro cerca de los 180 Degree-Sign K. Ambas anomalias termicas observadas en los monocalcogenidos surgen como consecuencia del desordenamiento del estado ferromagnetico y contrastan con la anomalia antiferro- magnetica hallada en el mononitruro isoestructural a 52 Degree-Sign K. Los nuevos datos termodinamicos concuerdan satisfactoriamente con los obtenidos mediante el procedimiento de evaluacion de entropia de Gronvold y Westrum. (author) [Russian] Rasprostranenie kriotermicheskih dannyh no U{sub 4}O{sub 9} na bolee vysokie temperatury pokazalo termofizicheskie aspekty (predpolagaemogo) postepennogo strukturnogo prevrashhenija tipa-A. pri temperature 348 Degree-Sign K s sootvetstvujushhim prirashheniem jentropii v razmere 1,84 kalorij/gramm-mol' OK, svjazannogo so smeshheniem vnedrennyh atomov kisloroda. Izmerenija kak teploemkosti, tak i magnitnoj vospriimchivosti na spechennoj dvuokisi urana Mol- linkrodta podtverdili, chto antiferromagnitnyj-paramagnitnyj perehod proishodit pri 30,4 Degree-Sign K so skachkom teploemkosti v 400 kalorij/gramm-mol' Degree-Sign K, a ne pri 28,7 Degree-Sign K s povysheniem teploemkosti na devjat' kalorij/gramm-mol' Degree-Sign K, kak soobshhalos' v literature. Jeto pozvoljaet teper' ob{sup j}asnit' termicheskuju anomaliju, obnaruzhennuju v {beta} -U{sub 3}O{sub 7}. Kriogennye teploemkosti, poluchennye na harakternyh obrazcah {alpha}-, {beta}-, i {gamma} utriokisi urana, podgotovlennyh doktorom E.G.P.Kordfunke iz Niderlandskogo reaktornogo centra, kombinirujutsja s teploemkostjami pri bolee vysokoj temperature, jental'pijami obrazovanija i drugimi termodinamicheskimi dannymi dlja poluchenija dannyh ob otnositel'noj stabil'nosti jetih vazhnyh jadernyh materialov. Obnaruzheno, chto kak monoselenid urana, tak i diselenid urana imejut anomalii tipa ljambda, svjazannye s magnitnym razuporjadocheniem. V diselenide urana jeto proishodit pri 13,1 Degree-Sign K s prirashheniem jentropii v 0,16 kalorij/gramm-mol' Degree-Sign K. Prirashhenie jentropii v monoselenide pri anomalii pri 160 Degree-Sign K sostavljaet velichinu 1,0 kalorij/gramm- mol' Degree-Sign K, chto mozhno sravnit' s velichinoj 1,17, poluchennoj dlja monosul'fida pri temperature okolo 180 Degree-Sign K. Obe termicheskie anomalii v monohal'kogenidah voznikajut vsledstvie razupo- rjadochenija ferromagnitnogo sostojanija i otlichajutsja ot antiferromagnitnoj anomalii, obnaruzhennoj v izostrukturnom mononitride pri temperature 52 Degree-Sign K. Novye termodinamicheskie dannye horosho soglasujutsja so shemoj ocenki jentropii Gronvold i Westrum. (author)

  6. Comparative study of smear layer removal by different etching modalities and Er:YAG laser irradiation on the root surface: a scanning electron microscopy study; Estudo comparativo, atraves de microscopia eletronica de varredura, da acao de diferentes substancias quimicas e do laser de Er:YAG, na remocao de smear layer, em superficies radiculares submetidas a raspagem e aplainamento

    Energy Technology Data Exchange (ETDEWEB)

    Theodoro, Leticia Helena

    2001-07-01

    The aim of this study was to compare the effects of citric acid, EDTA, citric acid with tetracycline, and Er:YAG laser to smear layer removal on the root surface after scaling with manual instruments by SEM. Thirty specimens (n=30) of root surface before scaling were divided into 6 groups (n=5). The Control Group (G1) was not treated; Group 2 (G2) was conditioned with citric acid gel 24%, pH1, during 2 minutes; Group 3 (G3) was conditioned with EDTA gel 24%, pH 7, during 2 minutes; Group 4 (G4) was conditioned with citric acid and tetracycline gel 50%, pH1 during 2 minutes; Group 5 (G5) was irradiated with Er:YAG laser (2.94 {mu}m), 47 mJ/10 Hz, focused, under water spray during 15 seconds and fluence of 0.58 J/cm{sup 2}; Group 6 (G6) was irradiated with Er:YAG laser (2.94{mu}m), 83 mJ/10 Hz, focused, under water spray during 15 seconds and fluence of 1.03 J/cm{sup 2}. The micrographic were analyzed by scores and following the statistical analysis with Kruskal Wallis (p<0.05) H=20,31. The G1 was significantly different of all groups (28.0); the G2 (13.4), G3 (11.7), and G4 (13.6) showed no difference in relation to G5 (20.3) and G6 (6.0), but the G6 was significantly different from G5. From the results, it can be conclude that: 1) there was intensity smear layer after scaling and root planing; 2) all treatments were effective to smear layer remove with significantly difference to G2, G3, G4, G5 and G6; G2, G3 and G4 were not statistically different from G5 and G6; 3) G6 was more effective in the smear layer remotion in relation to G5 and both presented irregular root surface. (author)

  7. Influence of different water-ethanol solvent systems on the spectroscopic and physico-chemical properties of the macrocyclic compounds pheophytin and chlorophyll a; Influencia de diferentes sistemas de solvente agua-etanol sobre as propriedades fisico-quimicas e espectroscopicas dos compostos macrociclicos feofitina e clorofila a

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Leonardo M.; Rodrigues, Maira R.; Oliveira, Hueder P. M. de [Universidade Camilo Castelo Branco, Sao Jose dos Campos, SP (Brazil); Lima, Adriana [Universidade do Vale do Paraiba, Sao Jose dos Campos, SP (Brazil); Soares, Rafael R. S.; Batistela, Vagner R.; Gerola, Adriana P.; Hioka, Noboru [Universidade Estadual de Maringa (UEM), PR (Brazil). Dept. de Quimica; Severino, Divinomar; Baptista, Mauricio S. [Universidade de Sao Paulo, (USP), SP (Brazil). Inst. de Quimica; Machado, Antonio Eduardo da Hora [Universidade Federal de Uberlandia (UFU), MG (Brazil). Inst. de Quimica

    2010-07-01

    This work focus on the influence of solvent on the photophysical properties of chlorophyll a and pheophytin. Both compounds are related to the photosynthesis process and are considered prototypes of photosensitizers in Photodynamic Therapy. Fluorescence measurements were developed using water/ethanol mixtures at different compositions, since both solvents could be employed in biological applications. The spectroscopic properties of these compounds undergo profound changes depending on water content in the ethanol due to auto-aggregation processes. The major hydrophobicity and the lower dielectric constant of ethanol when compared with water precluded significantly the auto-aggregation process of these compounds. (author)

  8. Computerized tomography with X-rays: an instrument in the analysis physico-chemical between formations and drilling fluids interactions; Tomografia computadorizada com raios-X: uma ferramenta na analise das interacoes fisico-quimicas entre as formacoes rochosas e fluidos de perfuracao

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Marcus Vinicius Cavalcante

    1998-12-31

    In this study it is demonstrated the applicability of the Computerized Tomography technique with x-rays to evaluate the reactivity degree between various drilling fluids and argillaceous sediments (Shales and Sandstones). The research has been conducted in the Rock-Fluid Interaction Pressure Simulator (RFIPS), where the possible physico-chemical alterations can be observed through successive tomography images, which are obtained during the flow of the fluid through the samples. In addition, it was noticed the formation of mud cake in Berea Sandstones samples in the RFIPS, though the Computerized Tomography with X-rays, when utilizing drilling fluids weighted with the baryte. (author) 35 refs., 38 figs., 5 tabs.

  9. Computerized tomography with X-rays: an instrument in the analysis physico-chemical between formations and drilling fluids interactions; Tomografia computadorizada com raios-X: uma ferramenta na analise das interacoes fisico-quimicas entre as formacoes rochosas e fluidos de perfuracao

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, Marcus Vinicius Cavalcante

    1999-12-31

    In this study it is demonstrated the applicability of the Computerized Tomography technique with x-rays to evaluate the reactivity degree between various drilling fluids and argillaceous sediments (Shales and Sandstones). The research has been conducted in the Rock-Fluid Interaction Pressure Simulator (RFIPS), where the possible physico-chemical alterations can be observed through successive tomography images, which are obtained during the flow of the fluid through the samples. In addition, it was noticed the formation of mud cake in Berea Sandstones samples in the RFIPS, though the Computerized Tomography with X-rays, when utilizing drilling fluids weighted with the baryte. (author) 35 refs., 38 figs., 5 tabs.

  10. Microbiological, physico-chemical, and sensorial modifications during the useful life of the shrimps (Penaeus brasiliensis e Penaeus Paulensis) submitted to gamma radiation.; Alteracoes microbiologicas, fisico-quimicas e sensoriais durante a vida util do camarao-rosa (Penaeus brasiliensis e Penaeus Paulensis) submetido a radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Mariana Del Ben

    2000-07-01

    During the last years, there has been an increase in the consumption of seafood and freshwater fish as a healthier diet option. Shrimps are the most important product in the international trade market. This kind of food easily deteriorates due to autolysis, oxidation and microbial action. This research was carried out in order to study the effectiveness of radiation in preserving shrimps. Samples of shrimps (Penaeus brasiliensis and P. paulensi) were submitted to gamma radiation doses of O kGy, 1 kGy, 2 kGy, 2.5 kGy, 3 kGy and 3.5 kGy and stored under refrigeration. The microbiological analysis was performed on days O, 2, 4, 7 10 and 14 post processing. Simultaneously, the pH and total, volatile bases (TVBN) were determined. The psychotropic population varied from <2.0 log to 8.08 log CFU/g while the mesophilic ranged from <1.0 109 to 6.03 log CFU/g; pH varied from 7.52 to 8.33 and TVBN from 28.47 to 56.00 mg N/100g, according to the radiation dose and the day of analysis. Black spots, changes in the characteristic odour and TVBN levels showed the beginning of a chemical deterioration as of the 4 th day of analysis. Doses of 3 kGy and 3.5 kGy presented the best results. Pseudomonas spp. showed the highest sensitivity to radiation. Due to the lapse of time between capturing shrimps and returning to land together with inadequate manipulation and storage in the boat, the quality of raw material is prejudiced which makes the radiation process unfeasible. (author)

  11. Effects of the modified atmosphere and irradiation on the microbiological, physical-chemical and sensory characteristics of the 'minas frescal' cheese;Efeitos da atmosfera modificada e da irradiacao sobre as caracteristicas microbiologicas, fisico-quimicas e sensoriais do queijo minas frescal

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, Vanessa Pires da

    2004-07-01

    The experiment was divided into two parts. Initially, it was studied the 'Minas Frescal' cheeses packed under atmospheric air, modified atmosphere of 70% CO2 and 30% N2 (ATM) and vacuum. Second the cheeses packed under these three treatments had been radiated by doses of 2 KGy. In the two parts of the experiment, it was analyzed the microbial evolution and, the sensory and physical-chemical characteristics of the cheeses under the different treatments during a 4 deg C-storage. In the first phase of the experiment it was verified that the ATM and the vacuum decreased the intensity of the total population growth of aerobic mesophilic and psychotropic and had reduced the population of Staphylococcus positive coagulase, but they had not been efficient controlling the total coliforms and Escherichia coli, while in control all the populations had continuously grown, according to the sensory characteristics of the cheeses, color, odor and appearance. These characteristics were kept the same during the 40 days of storage, and the control decreased the acceptability levels gradually, being rejected in the 17{sup th} day. In the second part of the experiment, it was observed that a 2KGy-irradiation over the 'Minas Frescal' cheeses reduced the populations of aerobic mesophilic, aerobic and anaerobic psychotropic, Staphylococcus positive coagulase, total coliforms and Escherichia coli. The ATM and vacuum treatments were very efficient therefore they prevented the growth of these microorganisms during the storage, while in control, the aerobic mesophilic and psychotropic population grew during the storage. According to sensory aspects, the ATM treatment was the most efficient one, because it kept the appearance, texture and flavor for more than 43 days while the vacuum kept for 36 days and the control for only 8 days. The use of the irradiation with modified atmosphere and low temperatures of storage increased the shelf life of the cheeses, hindering the growth of the microbial populations in the product and keeping product sensory characteristics. (author)

  12. Mitigation strategies of intergranular corrosion in systems of reactors of water boiling (BWR). Combined action of the chemistry of the hydrogen and the oxygen; Estrategias de mitigacion de la corrosion intergranular en sistemas de reactores de agua en ebullicion (BWR). Accion combinada de la quimica del hidrogeno y del oxigeno

    Energy Technology Data Exchange (ETDEWEB)

    Verdugo, M.

    2015-07-01

    Inter-Granular Stress Corrosion cracking (IGSCC) in austenitic stainless steel and in austenitic nickel-based alloys has been the subject of many studies the aim of which was to resolve one of the main problems faced by BWR nuclear power plants since the 1960s. This corrosion phenomenon is the result of the combined action of three factors: sensitization of the material, high local stresses and an aggressive medium. This paper deals with these factors separately and analyzes the oxidative chemistry of BWR reactors (aggressivity of the medium) as one the main causes if IGSCC. (Author)

  13. Petrography, mineral chemistry and lithochemistry of the albitite and granite-gneissics rocks of anomaly 35 from Lagoa Real uranium province; Petrografia, quimica mineral e litoquimica do albitito e das rochas granito-gnaissicas da anomalia 35, provincia uranifera de Lagoa Real

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Camila Marques dos

    2016-07-01

    In the northwestern portion of the Lagoa Real Uranium Province (LRUP), located in south-central Bahia, it is located one of the most promising uranium anomalies Brazil (an35, Gameleira I deposit), the reserves and proximity to the Cachoeira mine. Other anomalies of this sector (eg. 31 AN and AN34), are also considered strategic for the content of radioactive minerals and REE. The objective was to develop a study of a representative drill core of an35, where the main rocks PULR are present. The research focused on the mineralogical and chemical changes observed in the passages of a lithology to another, from the rock to the meta granitic albitites, through gneiss and transitional rocks, and making comparisons with similar lithologies sampled on testimonies of AN31 and 34. The granites are classified as hypersolvus coarse alkali-feldspar granite and are variably deformed. The main mineral assemblage in granites are perthitic orthoclase+hedenbergite+ quartz +hastingsite + biotite, and zircon, apatite, ilmenite and titanite are accessories. The reddening of these rocks are characterized by feldspars sericitization and hematitization and the presence of 'vazios'. The gneisses are mainly gray and reach milonitic to protomilonitics terms. These rocks have characteristics of subsolidus changes as swapped rims and metasomatic perthites. The tardi-magmatic association (amphibole+biotite) indicates final crystallization or late influx by superficial fluids resulting in an increase in water and volatiles, such as F and Cl in the system, which must also have carried rare-earth elementsGranites have geochemical affinity with A-type ferroan granite, A2, reduced and are post-collisional. Their patterns of incompatible elements and rare earths are comparable to Sao Timoteo Granite, but their petrographic features indicate that it is a less common granite facies. Albitites were classified as garnet albitites, magnetite albitites and biotite albitites. Contacts between albitites and gneisses are macroscopically gradational, however, in the garnet albitites replacement of granitic mineral facies by the albitite facies were observed petrographically, implying a granitic protolith for this rock. On the other hand, magnetite albitites do not have clear relationship with granites. Albitites usually have porphyroblastic texture with granoblastic polygonal matrix and chessboard texture in albite porphyroclasts. The garnet albitites comprise hedenbergite, hastingsite, garnet, magnetite and sphena. Magnetite albitites, in turn, have hedenbergite, Fe-edenite, biotite, martitized magnetite, allanite and sphene. The diopside+actinolite+eastonita association is late, and in these rocks, it is restricted to more deformed portions or filling voids. The biotite albitites comprise biotite, zircon and apatite hedenbergite (?). Mineralization occurs in magnetite albitites as thin lenses composed by sphene, magnetite, carbonate and zircon. The uranium mineral is the uraninite, which occurs filling spaces between crystals and sphene or albite granules. In comparison to granites, albitites have a higher content of Na{sub 2}O, MgO, V, W, Zr, Pb and Sr for and lower K{sub 2}O, SiO{sub 2} and F. They have a geochemical REE pattern that is identical to that of granite. The similarity between macroscopic granites and albitites, the presence of vazios, feldspar hematitization and sericitization causing macroscopical reddening in transitional portions and the replacement of potassic feldspar by albite and oligoclase are suggestive of episyenitization processes. The metasomatic perthites and presence of chessboard texture in porphyroclasts indicate successive albitization processes prior to deformation. The comparison between albitite samples of different drill cores and anomalies shows that there are differences in the formation and mineralization of these rocks. The V and Mg enrichment in some albitites suggests that these rocks may result from the interaction of fluids with different compositions with varied range of rocks, such as granite, syenite and mafic rocks. Thus, albitite s must be the result of successive processes of change influenced by the interaction of fluids with different rocks in the area, and varying compositionally on a local scale. (author)

  14. Identification, quantification and comparison between the chemical substances responsible for the irradiated pot still cachaca and commercial rum aromas; Identificacao, quantificacao e comparacao das substancias quimicas responsaveis pelos aromas da cachaca de alambique e do rum comercial tratados pelo processo de irradiacao

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Maria Djiliah Camargo Alvarenga de

    2006-07-01

    The irradiation process has being presented as an alternative technique in food preservation. When applied on beverages, radiation is mainly used for malt decontamination or sterilization of musts and had been proposed also to accelerate aging. Some confusion over rum and cachaca identities has arisen due to the internationalization of cachaca. This research aims to identify, quantify and compare the effect of gamma radiation on the aroma of the Brazilian spirit with rum, irradiated and non irradiated, by instrumental and sensory analysis. Results showed that the content of volatile compounds presented strong correlation with the radiation dose (0,150 and 300 Gy) for all the samples. According to Triangle Test for aroma, all the judges could distinguish among non irradiated and irradiated samples (300 Gy), aged cachaca from rum and non aged cachaca from rum, but they could not distinguish aged cachaca from non aged cachaca. Analysis of variance (ANOVA) of the results from the quantitative descriptive analysis showed that non irradiated non aged cachaca and rum were different in their alcohol, vinegar, vanilla, citrus, melon, spice, vegetal and grass except caramel and apple aroma attributes. Non irradiated cachaca and irradiated cachaca (300 Gy); and non irradiated rum and irradiated rum (300 Gy) were different in their apple, caramel, vinegar, vanilla, citrus, melon, spice, vegetal and grass except alcohol aroma attributes. According to the gas chromatography/olfactometry results, significant difference was found among non irradiated cachaca and rum; non irradiated cachaca and irradiated cachaca (300 Gy); and non irradiated rum and irradiated rum (300 Gy) when their aromas were compared. (author)

  15. Characterization and corrosion behavior of phytic acid coatings, obtained by chemical conversion on magnesium substrates in physiological solution; Caracterizacion y comportamiento frente a la corrosion de recubrimientos de acido fitico, obtenidos por conversion quimica, sobre substratos de magnesio en solucion fisiologica

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Alvarado, L. A.; Lomeli, M. A.; Hernandez, L. S.; Miranda, J. M.; Narvaez, L.; Diaz, I.; Garcia-Alonso, M. C.; Escudero, M. L.

    2014-10-01

    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 degree centigrade. The results indicate that phytic acid conversion coatings provided a very effective protection to the magnesium substrates studied. (Author)

  16. Microbiological testing and physical and chemical analysis of reconstituted fruit juices and coconut water
    Avaliação microbiológico e caracterização físico-quimica de refrescos e água de coco

    Directory of Open Access Journals (Sweden)

    F. B. PILÓ

    2010-04-01

    Full Text Available

    The aim of this study was to assess the quality of reconstituted fruit juices and coconut water sold for immediate consumption in bars, restaurants and bakeries, and by street vendors in Belo Horizonte (Minas Gerais, Brazil. Microbial quality was determined by counting coliforms, yeasts, staphylococci and salmonellae. Total titratable acidity, pH and total soluble solids of these beverages were recorded. For coconut water samples, the total reducing sugar content was also determined. The “juices” collected included reconstituted orange, cashew and grape-fl avored juice powders and concentrated cashew juice. Sixty samples of these juices and 45 of coconut water were collected. More than half (55% of the juice samples did not comply with current Brazilian legislation, which states that there must be a total absence of coliforms in a 50 mL sample. Sixteen percent of the coconut water samples exceeded the bacterial count limits defi ned in Brazilian law, with thermotolerant coliform densities above 102 MPN / mL. The high levels of sugar and low pH found in the coconut water were possibly related to the high yeast counts in most samples. Forty-seven percent of coconut water samples showed staphylococcal counts above 103 CFU/mL. The numbers of thermotolerant coliforms, yeasts and staphylococci found suggest unsatisfactory hygienic practices during the preparation of these beverages. Salmonellae were not detected in any of the samples. The physical and chemical properties of the drinks varied among the samples. Our results suggest that both the reconstituted juices and coconut waters need better hygienic and sanitary control.

  17. Study of chemical interaction induced by ionizing radiation poly(dimethylsiloxane-g-ethylene oxide) in the poly(n-vinyl-2-pyrrolidone) and agar membrane; Estudo da interacao quimica do poli(dimetilsiloxano-g-oxido de etileno) na membrana de poli(n-vinil-2-pirrolidona) e agar induzida com radiacao ionizante

    Energy Technology Data Exchange (ETDEWEB)

    Bazzi, Aurea de Souza

    1999-07-01

    Membrane composed by poly(N-vinyl-2-pyrrolidone) (PVP) and agar was formulated with and without poly(dimethylsiloxane-g-ethylene oxide) (SEO) irradiated with electron beam with doses between 10-50 kGy. The radiolytic behaviour of each component, PVP, agar and SEO, was studied when irradiated by gamma ray, in the absence and presence of air and water, by electron paramagnetic resonance (EPR) at 77 K. The chemical interaction of SEO with PVP/agar membrane was investigated by: infrared spectroscopy, energy dispersive X-ray fluorescence, dynamic-mechanical analysis, scanning electron microscopy, gel and swelling analysis. The cytotoxicity of the PVP/agar/SEO membrane was evaluated by cellular suppression. The membrane radicals from PVP ({phi}NC.) and from water (H., OH. and H{sub 2}O) was observed by EPR at 77K. The agar radicals formed by hydrogen abstraction of C{sub 1} and C{sub 3} of {beta}-D-galactose and/or C{sub 1} and C{sub 4} of {alpha}-L-galactose, reacted primarily with water radicals in despite of they also took part in the membrane by chemical bond. The radicals from SEO (.CH{sub 2}{approx}, .Si{approx}, .O{approx}) participated in the inter and intramolecular crosslinking as co-crosslinker by polymeric bridge. The co-crosslinked action depended on its concentration associated to PVP concentration. The presence op acrylates increases the tensile break of the PVP/agar/SEO membrane significantly. (author)

  18. Composicao quimica, perfil de acidos graxos e quantificacao dos acidos ƒ¿-linolenico, eicosapentaenoico e docosahexaenoico em visceras de tilapias (Oreochromis niloticus = Percentual composition, fatty acids and quantification of the LNA (Alfa-Linolenic, EPA (Eicosapentaenoic and DHA (Docosahexaenoic acids in visceras of Nile Tilapia (Oreochromis niloticus

    Directory of Open Access Journals (Sweden)

    Nilson Evelázio de Souza

    2005-01-01

    Full Text Available Foi avaliada a composição química de vísceras de tilápias (Oreochromis niloticus criadas em cativeiro Os teores de umidade, cinza, proteína bruta e lipídios totais foram de 64,4%; 1,3%; 6,3% e 18,0%, respectivamente, caracterizando alta concentração de lipídiostotais em relação a outros resíduos de peixes. Foram identificados 49 ácidos graxos, sendo majoritários os ácidos: oléico, (32,8%, seguido do palmítico, (19,9% e linoléico, (18,2%. As razões entre n-6/n-3 e ácidos poliinsaturados/saturados foram de 5,5 e 0,9, respectivamente. As quantificações dos ácidos graxos alfa-linolênico, eicosapentaenóico e docosahexaenóico, em mg/g de lipídios totais, foram de 10,4, 1,4 e 9,3, respectivamente. O elevado teor de lipídios totais das vísceras contribuiu significativamente para as quantidadesde ácidos graxos n-3. Todos os parâmetros analisados foram satisfatórios sob o ponto de vista nutricional e neste sentido as vísceras de tilápias poderão ser utilizadaa para alimentar peixes ou outros animais.The chemical composition was evaluated in visceras of tilapias raised in captivity. The moisture, ash, crude protein and total lipids contents were 64.4%; 1.3%; 6.3% and 18.0%, respectively, characterizing high total lipids concentration in relation other residues of fish. Forty nine fatty acids were detected, the major fatty acids were oleic (32.8%, palmitic (19.9% and linoleic-1 (18.2% and oleic (9.4%. The ratio n-6/n-3 and polyunsaturated/saturated fatty acids, showed the values 5.5 and 0.9, respectively. The quantifications of alfa-linolenic, eicosapentaenoic and docosahexaenoic acids (in mg/g of total lipids, were 10.4, 1.4 and 0.3, respectively. The higher contents of total lipids in visceras contributed significantly for amounts of n-3 fatty acids. All the parameters analyzed were shown nutritional value satisfactory in this sense visceras of tilapias can be used in the feed of fish and other animal.

  19. Chemical synthesis, characterization studies and reactivity of a catalytic material based on ZrO{sub 2}-H{sub 3}PW{sub 12}O{sub 40}; Sintesis quimica, estudios de caracterizacion y reactividad de un material catalitico a base de ZrO{sub 2}-H{sub 3}PW{sub 12}O{sub 40}

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Enriquez, Juan Manuel; Garcia Alamilla, Ricardo; Paramo Garcia, Ulises; Rodrigo, Rebeca Silva [Instituto Tecnologico de Ciudad Madero, Tamaulipas (Mexico). Division de Estudios de Posgrado e Investigacion; Garcia Serrano, Luz Arcelia, E-mail: jmanuelher@hotmail.com [Instituto Politecnico Nacional, Mexico, D.F. (Mexico). Centro Interdisciplinario de Investigaciones y Estudios sobre Medio Ambiente

    2013-10-01

    In this work, the preparation and characterization of materials such as zirconium oxide (ZrO{sub 2}) and phosphotungstic acid promoted zirconium oxide (ZrO{sub 2}-H{sub 3}PW{sub 12}O{sub 40}) is presented. Physico-chemical characterization results showed that addition of H{sub 3}PW{sub 12}O{sub 40} acted as both a textural and chemical promoter of zirconium oxide. The incorporation of phosphotungstic acid into the ZrO{sub 2} matrix delayed the sintering of the material and stabilized ZrO{sub 2} in the tetragonal phase. ZrO{sub 2} acidity was also enhanced, developing strong acid sites on its surface. The Pt/ZrO{sub 2}-H{sub 3}PW{sub 12}O{sub 40} catalyst was active for n-pentane isomerization at 250 deg C, exhibiting high selectivity to iso-pentane (95%). This result is probably due to its suitable acidity (author)

  20. Physical, chemical and radioactive characterization of co-products from titanum dioxide industry for valorization in the cement industry; Caracterizacion fisico-quimica y radiactiva de los sub-productos provenientes de la industria de dioxido de titanio para su valorizacion en la industria del cemento: implicaciones radiologicas.

    Energy Technology Data Exchange (ETDEWEB)

    Gazquez, M.J.; Mantero, J.; Bolivar, J.P.; Garcia-Tenorio, R.; Vaca, F.

    2011-07-01

    The present study was conducted to characterize the raw materials (ilmenite and slag), waste (red gypsum) and several co-products (sulphate monohydrate and sulphate heptahydrated) form the titanum dioxide industry in relation to their elemental composition (major, minor and trace elements), granulometry, mineralogy, microscopic morphology, physical composition and radioactive content in order to apply this knowledge in the valorization of the co-products in the fields sucha as construction, civil engineering, etc. In particular, the main properties of cements produced with different proportions of red gypsum were studied, and the obtained improvements, in relation to Ordinary Portland Cements (OPC) were evaluated. It was also demonstrated that the levels of pollutants and the radioactive content in the produced RG cements, remain within the regulated safety limits. (Author). 38 refs.

  1. Physical, chemical and radioactive characterization of co-products from titanium dioxide industry for valorization in the cement industry; Caracterizacion fisico-quimica y radiactiva de los sub-productos provenientes de la industria de dioxido de titanio para su valorizacion en la industria del cemento: implicaciones radiologicas.

    Energy Technology Data Exchange (ETDEWEB)

    Gazquez, M.J.; Mantero, J.; Bolivar, J.P.; Garcia-Tenorio, R.; Vaca, F.

    2011-07-01

    The present study was conducted to characterize the raw materials (ilmenite and slag), waste (red gypsum) and several co-products (sulphate monohydrate and sulphate heptahydrated) form the titanium dioxide industry in relation to their elemental composition (major, minor and trace elements), granulometry, mineralogy, microscopic morphology, physical composition and radioactive content in order to apply this knowledge in the valorization of the co-products in the fields such a as construction, civil engineering, etc. In particular, the main properties of cements produced with different proportions of red gypsum were studied, and the obtained improvements, in relation to Ordinary Portland Cements (OPC) were evaluated. It was also demonstrated that the levels of pollutants and the radioactive content in the produced RG cements, remain within the regulated safety limits. (Author). 38 refs.

  2. Behavior patterns of chemical and isotopic species (2006-2007) in the Los Azufres, Mich., geothermal field, as a response to reinjection; Patrones de comportamiento de especies quimicas e isotopicas (2006-2007) en el campo geotermico de Los Azufres, Mich., en respuesta a la reinyeccion

    Energy Technology Data Exchange (ETDEWEB)

    Barragan R, Rosa Maria; Arellano G, Victor Manuel; Martinez E, Ignacio; Aragon A, Alfonso [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rmb@iie.org.mx; Reyes D, Lisette; Gonzalez, Rubi [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia de Los Azufres, Morelia, Michoacan (Mexico)

    2009-07-15

    Chemical and isotopic ({delta}18 O y {delta}D) data from the Los Azufres geothermal field fluids for 2006 and 2007 were analyzed to investigate changes in their behavior patterns and their relation to reinjection. Total discharge chlorides, reservoir temperatures, excess steam in well feeding fluids, CO{sub 2} concentrations at reservoir and total discharge conditions, and liquid saturations were calculated. Contour lines of certain parameters were obtained for 2006 and 2007 to relate them to the contours obtained for 2005 and to the reinjection histories. Fluid isotopic compositions, including injection fluids, were correlated to estimate fluid mixing effects between the reservoir and reinjection fluids. Results suggest chemical parameters respond to the mass flow rate injected and to the isotopic composition of injection fluids. {delta}D vs {delta}18 O relationships show a number of wells produce different proportions of reinjection returns. In the northern zone, wells AZ-65D, AZ-13, AZ-32, AZ-9A, AZ-9AD, AZ-28A, AZ-69D and AZ-44 produce relatively high proportions, while wells AZ-5, AZ-28 and AZ-19, among others, produce lower proportions. Wells AZ-2A, AZ-16AD, AZ-46 and AZ-33 from the southern field zone produce higher proportions of reinjection returns while wells AZ-34, AZ-36 and AZ-37 produce lower proportions. The liquid saturation distribution in 2007 shows the maximum saturation zones have decreased compared with 2005 and 2006 data. In 2007, maximum liquid saturations were found around wells AZ-22 and AZ-23 (southern zone) and AZ-28, AZ-32, AZ-45 and AZ-48 (northern zone). Minimum saturations were found around wells AZ-6 and AZ-16 (southern zone) and AZ-56 (northern zone). The CO{sub 2} levels for the reservoir liquid were used to trace paths of reinjection fluids, considering these fluids are depleted in this gas. Thus the minimum CO{sub 2} contour lines indicate the movement of the reinjection fluids in the reservoir. [Spanish] Se analizaron datos quimicos e isotopicos ({delta}18 O y {delta}D) de fluidos de pozos del campo geotermico de Los Azufres, Mich., obtenidos en 2006 y 2007, para investigar los cambios ocurridos en sus patrones de comportamiento y su relacion con el proceso de reinyeccion de fluidos al yacimiento. El analisis de los datos comprendio las estimaciones de cloruros en las descargas totales, temperaturas de yacimiento, exceso de vapor en los fluidos de alimentacion, las concentraciones de CO{sub 2} en las descargas totales y en la fase liquida del yacimiento y las saturaciones de liquido en la formacion. Con los resultados se elaboraron mapas de isovalores de los parametros mencionados correspondientes a 2006 y 2007 para investigar su evolucion con respecto a los mapas obtenidos en 2005, asi como su relacion con las historias de reinyeccion. Se correlacionaron las composiciones isotopicas de los fluidos incluyendo los de reinyeccion para estimar efectos de mezcla de fluidos. Los resultados indican que las variables estudiadas responden a las tasas de reinyeccion en el campo. Las relaciones {delta}D vs {delta}18 O indican que un buen numero de pozos del campo producen diferentes proporciones de retornos de reinyeccion; en la zona norte los pozos AZ-65D, AZ-13, AZ-32, AZ-9A, AZ-9AD, AZ-28A, AZ-69D y AZ-44 producen una mayor proporcion mientras que los pozos AZ-5, AZ-28 y AZ-19 entre otros, producen una menor proporcion. En la zona sur los pozos AZ-2A, AZ-16AD, AZ-46 y AZ-33 producen relativamente altas proporciones de retornos de reinyeccion mientras que los pozos AZ-34, AZ-36 y AZ-37 producen menores proporciones. La distribucion de saturaciones de liquido hallada en 2007 muestra que las areas de maxima saturacion han disminuido con respecto a las distribuciones de este parametro en 2005 y 2006. En 2007 las saturaciones maximas de liquido se localizaron alrededor de los pozos AZ-22 y AZ-23 (zona sur) y AZ-28, AZ-32, AZ-45 y AZ-48 (zona norte), mientras que las saturaciones minimas se localizaron en los pozos AZ-6 y AZ-16 (zona sur) y AZ-56 (zona norte). El CO{sub 2} del liquido del yacimiento mostro ser eficaz para trazar el avance de los fluidos inyectados, agotados en CO{sub 2}, hacia las zonas productoras de los pozos.

  3. Preliminary experiments on the use of radioactive indicators in macromolecular chemistry; Experiences preliminaires sur l'utilisation des indicateurs radioactifs en chimie macromoleculaire; Predvaritel'nye opyty ispol'zovaniya radioaktivnykh indikatorov v makromolekulyarnoj khimii; Ensayos preliminares sobre el empleo de indicadores radiactivos en quimica macromolecular

    Energy Technology Data Exchange (ETDEWEB)

    De Brouckere, L; Van Leemput, R; Stein, R [Laboratoire de Chimie Generale II, Universite Libre de Bruxelles (Belgium)

    1962-03-15

    In studies of osmotic phenomena with high polymers, two causes of error are particularly important: (a) Diffusion of low-molecular-weight polymers across the membrane; (b) Polymer adsorption on the membrane. For investigations on both these phenomena radiotracer methods present decisive advantages over the classical and far less sensitive gravimetric procedures. The polymer used in the authors' experiments was a hetero-disperse sample of (poly) chloro-butyl acrylate which was ionically chlorinated with Cl{sup 36} starting from a sample of (poly)butyl acrylate. This polymer was dissolved in acetone. Diffusion chambers similar to twin-cell osmometers were set up. Cellophane membranes with permeabilities of 6.7 x 10{sup -5} h{sup -1} to 30.6 x 10{sup -5} h{sup -1} separated the solution from the solvent. It was found that: (a) With our apparatus, about two hundred hours were necessary to reach an equilibrium or steady state in diffusion experiments; (b) The fraction of polymer diffusing through the membrane in a given time was independent of the concentration; (c) The amount of polymer diffusing was related to the permeability of the membrane; (d) A practically irreversible adsorption of polymer on the membrane was observed (30 to 40 {mu}g/cm{sup 2}). (author) [French] Dans les etudes sur les phenomenes osmotiques avec de hauts polymeres, deux causes d'erreurs sont particulierement importants : a) La diffusion des polymeres de faible poids moleculaire a travers la membrane; b) L'adsorption des polymeres sur la membrane. Pour les recherches sur ces deux phenomenes, la methode des radiotraceurs presente des avantages decisifs par rapport aux procedes gravi metriques classiques, beaucoup moins sensibles. Le polymere utilise dans les experiences des auteurs etait un echantillon a dispersion heterogene acrylate de (poly) chloro-butyle, obtenu par chlorruation ionique d'un echantillon d'acrylate de (poly)butyle avec du chlore-36. Ce polymere etait dissous dans de l'acetone. On a utilise des chambres de diffusion analogues aux osmometres a cellules jumelles. Des membranes de cellophane de permeabilite 6,7 {center_dot} 10{sup -5} h{sup -1} a 30,6 {center_dot} 10{sup -5} h{sup -1} separaient la solution du solvant. On a constate: a) Qu'avec l'appareil utilise dans les experiences de diffusion, il fallait environ deux cents heures pour atteindre un etat d'equilibre ou un etat stationnaire; b) Que la fraction de polymere se diffusant a travers la membrane dans un temps donne etait independante de la concentration; c) Que la quantite de polymere diffuse variait en fonction de la permeabilite de la membrane; d) Qu'il se produisait une adsorption pratiquement irreversible du polymere sur la membrane (30 a 40 {mu}g/cm{sup 2}). (author) [Spanish] Las dos principales fuentes de error cuando se estudian fenomenos osmoticos con polimeros de elevado peso molecular son: a) la difusion de polimeros de bajo peso molecular a traves de la membrana; b) la adsorcion de polimeros en la membrana. Los metodos que emplean trazadores radiactivos para la investigacion de estos dos fenomenos ofrecen ventajas decisivas sobre los procedimientos gravimetricos clasicos, que son mucho menos sensibles. El polimero empleado por los autores consistio en una muestra heterodispersa de policloroacrilato de butilo obtenido por el oracion ionica del poliacrilato de butilo con {sup 36}Cl. Este polimero se utilizo disuelto en acetona. Los autores emplearon camaras de difusion, semejantes a osmomotros de celulas gemelas. La solucion quedaba separada del disolvente por membranas de celofan de permeabilidades de 6,7 x 10{sup -5} h{sup -1} a 30,6 x 10{sup -5} h{sup -1}. Han llegado a las conclusiones siguientes: a) con el aparato empleado en los experimentos de difusion, se precisan unas 200 horas para alcanzar un estado de equilibrio o un regimen estacionario; b) la fraccion de polimero que difunde a traves de la membrana en un tiempo determinado es independiente de la concentracion; c) la cantidad de polimero que se difunde depende de la permeabilidad de la membrana; d) se observa una adsorcion practicamente irreversible del polimero en la membrana (30 a 40 {mu}g cm{sup 2}). (author) [Russian] Pri izuchenii osmoticheskikh yavlenij s ispol'zovaniem vysokikh polimerov osoboe znachenie predstavlyayut dve prichiny oshibok: a) diffuziya nizkomolekulyarnykh polimerov cherez membranu; b) adsorbtsiya polimera na membrane. Dlya issledovaniya oboikh ehtikh yavlenij metod radioaktivnykh indikatorov predstavlyaet nesomnennye preimushchestva nad obychnymi i gorazdo menee chuvstvitel'nymi vesovymi metodami. V provedennykh avtorami doklada opytakh byl ispol'zovan geterodispersnyj obrazets polimera (poli)-khlorobutilakrilata, kotoryj byl khlorirovan s pomoshch'yu Cl{sup 36} posredstvom ionizatsii, iskhodya iz obraztsa (poli)-butilakrilata. Ehtot polimer rastvo- ryaetsya v atsetone. Byli postroeny diffuzionnye kamery, analogichnye dvuyacheechnym osmometram. Rastvor otdelyalsya ot rastvoritelya tselofanovymi membranami, obrabotannymi tak, chtoby davat' pronitsaemost' ot 6,7 x 10{sup -5} ch{sup -1} do 30,6 x 10{sup -5} ch{sup -1} Bylo najdeno, chto: a) s nashim oborudovaniem ponadobilos' okolo 200 chasov dlya togo, chtoby v opytakh diffuzii dostich' ravnovesiya ili ustojchivogo sostoyaniya; b) dolya polimera, diffundiruyushchaya cherez membranu v opredelennyj promezhutok vremeni, ne zavisit ot kontsentratsii; c) kolichestvo diffundiruyushchego polimera zavisit ot pronitsaemosti membrany; d) nablyudalas' pochti neobratimaya adsorbtsiya polimera na membrane (30-40 {mu}g/cm{sup 2}). (author)

  4. Heat treatment and gamma radiation effects on the physical-chemical, microbiological and sensory stability of pure sugarcane juice or added with fruit juices, stored under refrigeration;Efeitos do processamento termico e da radiacao gama na estabilidade fisico-quimica, microbiologica e sensorial de caldo de cana puro e adicionado de suco de frutas, armazenado sob refrigeracao

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Aline Cristine Garcia de

    2007-07-01

    Sugarcane juice is a taste drink, energetic, no alcoholic that conserves all the nutrients in cane sugar. It was very appreciated by the Brazilian population and its production has been shown to be a highly lucrative business. This research had the following objectives: evaluate the acceptance of the consuming market and the stability of pure sugarcane juice or added with natural fruit juices, submitted of heat treatment (70 deg C/ 25 min) and/ or gamma radiation (2,5 kGy) and stored in high density polyethylene bottles, under refrigeration (5 +- 1 deg C). Sugarcane juice market test was evaluated through the application of 350 questionnaires on six Sao Paulo cities. Sugarcane juice stability was evaluated through microbiological (psychotropic count, lactic bacteria and yeasts and molds count), physical-chemical (pH, color, titratable acidity, soluble solids, ratio and polyphenoloxidase activity) and sensory (hedonic test) parameters. Centesimal composition was determined analyzing: humidity, caloric value, total carbohydrates, total and reducing sugars, lipids, proteins, ascorbic acid, ash and minerals. Sugarcane juice shelf life period was determinate ever 7 days over a period of 42 days stored under refrigeration. The data were submitted to the variance analysis and compared by Tukey's test (p<0,05). Among the 350 interviewed people, more of the half one is interested about its habitual food safe and care about street foods. Sandwiches had been cited foods as routinely consumed, followed for the sugarcane juice and 'pastel'. Among the interviewed ones, 80% had mentioned to appreciate sugarcane juice. It had not correlation between age and school age and the preference for the consumption form was with lemon juice addition. About 55% of the interviewed ones had mentioned that would more frequently consume sugarcane juice processed and packed. Sugarcane juice processing did not modify the flavor and taste of the drink. It was concluded from the sensory analyses that the best mixture was that formulated with sugarcane juice and 4% of lemon juice as well as 10% of pineapple juice. Sugarcane juice centesimal composition was not altered by fruit juice concentration addition. However, sugarcane juice added with 10% pineapple juice incremented manganese and reducing sugars when compared with pure sugarcane juice and added with 4% lemon juice. The market test proffered mixture was shown to be that containing sugarcane juice and natural lemon juice for evaluation the shelf life. Sugarcane juice added with 4% of lemon juice submitted to gamma radiation, heat treatment combined with gamma radiation and heat treatment remaining satisfactory microbiological, sensory and physical chemical characteristics until 28, 35 and 42 days respectively, after processing. These results indicated that the heat treatment was effective for sugarcane juice preservation. (author)

  5. Dosimetry of radon, thorium and their progenies in the environment of a chemistry lab and crude in Zulia State, Venezuela; Dosimetria de radon, toron y sus progenies en el entorno de un laboratorio de quimica y crudo en el Estado Zulia, Venezuela

    Energy Technology Data Exchange (ETDEWEB)

    Pineda, L.; Viloria, T., E-mail: lendavaI22@hotmail.com, E-mail: lpineda@fing.luz.edu.ve, E-mail: tviloria63@yahoo.es [Universidad del Zulia, Maracaibo (Venezuela, Bolivarian Republic of). Departamento de Fisica; Palacios, D.; Sajo-Bohus, L., E-mail: sajobohus@gmail.com, E-mail: sanjuro.perdomo@gmail.com [Universidad Simon Bolivar, Caracas (Venezuela, Bolivarian Republic of). Laboratorio de Fisica Nuclear

    2013-07-01

    The main objective of this study was to estimate the dose rate of inhalation and the annual contribution of effective dose in the mixed field of radon and thoron in the environment of laboratory chemicals and oil from Zulia State, Venezuela, due to manipulation and storage of oil samples and water production.

  6. Stability evaluation and chemical characterization of different vegetable oils viewing the search for candidates for certified reference materials for bio diesel; Avaliacao da estabilidade e caracterizacao quimica de diferentes oleos vegetais visando a busca de candidatos a materiais de referencia certificado (MRC) para biodiesel

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Georgiana F. da; Fonseca, Mauricio G.; Goncalves, Lenise V.F.; Silva, Regina Celia F. da; Silva, Fernanda M.R. da; Rodrigues, Janaina M. [Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (LABOR/INMETRO), Duque de Caxias, RJ (Brazil). Lab. de Analises Organicas; Leal, Rodrigo V.P. [Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (LAMBOC/INMETRO), Duque de Caxias, RJ (Brazil). Lab. de Motores, Combustiveis e Lubrificantes], Email: rvleal@inmetro.gov.br; Cunha, Valnei S. [Instituto Nacional de Metrologia, Normalizacao e Qualidade Industrial (DIMCI/INMETRO), Duque de Caxias, RJ (Brazil). Diretoria de Metrologia Cientifica e Industrial

    2009-07-01

    Viewing the characterization of the various vegetable oils aiming to obtain a data bank that allows the production of certified reference materials for bio diesel of different blends, a study of chemical-physical characterization of different oils and derivative of bio diesel.

  7. A gestão de resíduos de laboratório na visão de alunos de um curso de graduação de quimica e áreas afins Waste laboratory management under the viewpoint of undergraduate students of a chemistry course and related areas

    Directory of Open Access Journals (Sweden)

    Zélia Therezinha Custódio Leite

    2008-01-01

    Full Text Available This work presents the students´ profile before and after working in the course "Laboratory Chemical Waste Treatment" in the last ten years. The structure of the course is also described. Although students have shown an increasing previous experience on waste management, many fundamental aspects are missing, especially knowledge on the directives focusing environmental aspects. Visits to industrial plants are also essential to better understand the impact of wastes in environment. Most students nowadays consider waste management as an essential part of their professional formation. A good waste management program must consider several topics of extreme relevance.

  8. Influence of the precursors in the chemical preparation of {gamma} - Al{sub 2}O{sub 3} in reactions of alcohols dehydration; Influencia de los precursores en la preparacion quimica de {gamma} - Al{sub 2}O{sub 3} en reacciones de deshidratacion de alcoholes

    Energy Technology Data Exchange (ETDEWEB)

    Salmones, J.; Limon, M.T.; Mayagoitia, V.; Rojas, F.; Kornhauser, I.; Morales, J.; Acosta, D. [Instituto Mexicano del Petroleo, Subdireccion General de Investigacion Aplicada, Apartado Postal 14-805, 07730, Mexico D.F. (Mexico)

    1998-12-31

    A chemical method for the synthesis of alumina substrates based on a microscopic morphological control, is presented. The influence of the precursor alcohol used for the synthesis of Al(OR){sub 3} is studied too. This latter compound is the raw material to synthesize the alumina materials treated here. The effects of alcohols such as ethanol, isopropanol and ter butanol are analyzed. Results show that an early formation (i.e. at low temperature) of the porous structure is reached in the case of {gamma} -Al{sub 2}O{sub 3} synthesized from ethanol. On the other hand, pore formation for alumina obtained from isopropanol and ter butanol, occurs until appearance of the {gamma} phase (at approximately 500 Centigrade). The different alumina substrates were used as catalysts in dehydration reactions of primary, secondary and tertiary alcohols. Decreasing catalytic activity corresponds to the sequence: (R-OH){sub 3} < (R-OH){sub 2} < (R-OH) in the case of ethanol; while for isopropanol and ter butanol the sequence is: (R-OH) < (R-OH){sub 2} < (R-OH){sub 3}. These results are explained by means of a reaction mechanism which is associated with the textural properties of the catalysts. (Author)

  9. Atomic Energy Levels. As Derived From the Analyses of Optical Spectra. Volume 3

    Science.gov (United States)

    1958-05-01

    Quimica (Madrid) [Al 46, 328 (1952). (I P) K. 0. Kessler and R. E. Trees, Phys. Rev. (2) 32, 303 (1953). (hfs) H. E. Walchii, A Tab/ of Nuclear .omena Data...I and 11. ________ 6. Reference 111 H. E. Walchli, A Tabl of Nuclear Momenti Data, Oak Ridge [101 R. T. Birge, Rev. Mod. Phys. 13, No. 4, 237 (1941...to (141 M. A. Catalin y R. Velasco, An. Real Soc. Foip. Fillica y Ac, in press (1958). Quimica (Madrid) [A] 48, 247 (1952). 161 C. E. Moore

  10. International Conference on Photochemistry (15th) Abstracts of Invited Lectures and Oral and Poster Contributions Held in Paris, France on 28 July-2 August 1991 (XVeme Conference Internationale de Photochimie, Paris, France 28 Juillet-2 Aout 1991)

    Science.gov (United States)

    1991-08-01

    M. Novo, C. Rios, F. Rodrlguez PrIelo Dpto. Quimica Fisica. Universidad de Santiago. E-15706 Santiago de Compostela. SPAIN. Ground- and excited-state...Sebastiao J. Formosinh Jo~o S. Brancod), and M. Mendes M.M. Fernandes a ) a) Instituto Superior de Engenharia de Coimbra,3000-Coibra,Portugal b) Department of...Braslavskyl, and Kurt Schaffner i I 3Max-Planck-Institut far Strahlenchemie, D.4330 M~lhem a.d. Ruhr, Stiftstrafle 34- 36, FRG. ’ Departamento de QuImica

  11. Calibration and study of the measurement capabilities of real-time gamma spectrometry equipment developed for the renewal of the network of stations automatic monitoring environmental radiation of the Generalitat of Catalunya; Calibracion y estudio de las capacidades de medida de los equipos de espectrometria gamma en tiempo real desarrollados para la renovacion de la Red de Estaciones Automaticas de vigilancia radiologia ambiental de la Generalitat de Catalunya

    Energy Technology Data Exchange (ETDEWEB)

    Casanovas, R.; Prieto, E.; Salvado, M.

    2014-10-01

    The renewal of the automatic environmental radiation surveillance network of the Generalitat of Catalunya has been carried out through the development and implementation of gamma-spectrometry-based equipment. the monitors use scintillation crystals, either Na(TI) or LaBr{sub 3}(Ce) and currently, there are 3 types of equipment water radioactivity monitors, aerosols on a particulate filter monitors and direct measurement monitors. In this paper, we expose the basic features of its operation, the details of their calibration and the minimum detectable activity concentration for some isotopes. (Author)

  12. Calibration and study of the measurement capabilities of real-time gamma spectrometry equipment, developed for the renewal of the network of automatic stations for environmental radiological surveillance of the Generalitat de Catalunya; Calibracion y estudio de las capacidades de medida de loes equipos de espectrometria gamma en tiempo real desarrollados para la renovacion de la Red de Estaciones Automaticas de vigencia radiologica ambiental de la generalitat de Catalunya

    Energy Technology Data Exchange (ETDEWEB)

    Casanovas, R.; Prieto, E.; Salvado, M.

    2013-07-01

    The renewal of the automatic environmental radiation surveillance network of the Gereralitat of Catalunya has been carried out through the development and implementation of gamma-spectrometry-based equipment. The monitors use scintillation cristals, either NaI(Tl) or LaBr{sub 3}(Ce) and currently, there are 3 types of equipment: water radioactivity monitors, aerosols on a particulate filter monitors and direct measurement monitors. In this paper, we expose the basic features of its operation, the details of their calibration and the minimum detectable activity concentrations for some isotopes.

  13. Quantification of {sup 232}Th, {sup 234}U, {sup 235}U and {sup 238}U in river mollusks by magnetic sector mass spectrometry with inductively coupled plasma source (Icp-SFMS); Cuantificacion de {sup 232}Th, {sup 234}U, {sup 235}U y {sup 238}U en moluscos de rios por espectrometria de masas de sector magnetico con fuente de plasma acoplado inductivamente (ICP-SFMS)

    Energy Technology Data Exchange (ETDEWEB)

    Arevalo R, D. L.; Hernandez M, H.; Romero G, E. T.; Lara A, N. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Alfaro de la T, M. C., E-mail: arevalo0591@hotmail.com [Universidad Autonoma de San Luis Potosi, Dr. Salvador Nava s/n, Zona Universitaria, 78290 San Luis Potosi, SLP (Mexico)

    2016-09-15

    The present work deals with the methodology established for the quantification of {sup 232}Th, {sup 234}U, {sup 238}U and {sup 235}U in the shell of gastropod mollusks collected in the rivers Valles, Coy and Axtla of San Luis Potosi, Mexico, which belong to the Panuco River basin; these rivers have as main source of pollution the discharge of municipal sewage, waste from small industries, agricultural and cattle residues and from natural sources. Conventional methods for measuring radio-nuclides are confronted with certain conditions related to the requirement in measurement, basically in the characterization that is related to the concepts of precision and accuracy. The analysis of the gastropod mollusk shell was performed by the Icp-SFMS technique; the main advantages of this technique lie in the isotope quantification capacity, the high precision and the low limits of detection, in this study are very important because these elements are in concentrations between ppb and ppt. This technique allowed the analysis of the samples having a complex matrix by the presence CaCO{sub 3} minimizing the interferences thanks to the ionization efficiency of the Ar plasma. For the species Pachychilus monachus were found concentrations of {sup 232}Th of 0.16-5.37 μg/g and of total U of 0.101-4.081 μg/g being this species where the highest values of total U were found. For Thiara (melanoids) tuberculata the lowest values were found among the different species ({sup 232}Th 0.61-3.61 μg/g and total U 0.006-0.042 μg/g), for Pachychilus suturalis, values of {sup 232}Th of 0.58-6.4 μg/g and for Pachychilus sp. were found between 0.26-7.62 μg/g and for total U values between 0.28-3.33 μg/g. The method offers several advantages: speed, good precision, low values of quantification limits and high sensitivity in the measurement of radio-nuclides and heavy metals. (Author)

  14. Determinação simultânea de As, Cd e Pb em amostras de água purificada para hemodiálise por espectrometria de absorção atômica com forno de grafite, após otimização multivariada baseada no uso de planejamento experimental Simultaneous determination of arsenic, cadmium and lead by GF AAS in purified water samples for hemodialysis after multivariate optimization based on factorial design

    Directory of Open Access Journals (Sweden)

    Lisia Maria G. dos Santos

    2008-01-01

    Full Text Available This paper reports the development of a methodology for simultaneously determining As, Cd and Pb, employing GF AAS with polarized Zeeman-effect background correction. In order to make the procedure applicable, the influence of pyrolysis and atomization temperatures and the amount of chemical modifiers were studied. Factorial and central composite designs were used to optimize these variables. Precision and accuracy of the method were investigated using Natural Water Reference material, Nist SRM 1640. Results are in agreement with certified values at the 95% confidence limit when the Student t-test is used. This methodology was used for quality control of purified water for hemodialysis.

  15. Determinação de As em amostras orgânicas de interesse ambiental por espectrometria de absorção atômica com atomização eletrotérmica após combustão em bomba de O2 Determination of As in environmental organic samples by atomic absorption spectrometry with electrothermal atomization after O2 bomb combustion

    Directory of Open Access Journals (Sweden)

    Vera Maria da Costa Dias

    2003-10-01

    Full Text Available The toxicity of the major As species present in the environment justifies the effort for quantifying the element in environmental organic samples, which can vary from animal and vegetal tissues to coal and industrial residues. This paper comments about the applicability of the O2 bomb digestion, as a general procedure for all environmental organic materials. A rapid and straightforward method is suggested, which consists in burning the sample in the bomb at high O2 pressure, dissolving the vapours in diluted HNO3 and determining As in the resulting solution by atomic absorption spectrometry with electrothermal atomization. The method was applied to certified materials and plant samples.

  16. Determinação de As em amostras orgânicas de interesse ambiental por espectrometria de absorção atômica com atomização eletrotérmica após combustão em bomba de O2 Determination of As in environmental organic samples by atomic absorption spectrometry with electrothermal atomization after O2 bomb combustion

    OpenAIRE

    Vera Maria da Costa Dias; Maria Salete Selaimen Satte

    2003-01-01

    The toxicity of the major As species present in the environment justifies the effort for quantifying the element in environmental organic samples, which can vary from animal and vegetal tissues to coal and industrial residues. This paper comments about the applicability of the O2 bomb digestion, as a general procedure for all environmental organic materials. A rapid and straightforward method is suggested, which consists in burning the sample in the bomb at high O2 pressure, dissolving the va...

  17. Carbon-14 and Hydrogen-3 Measurement by Means of a Liquid Scintillation Spectrometer: Colour Quenching; Mesure du Carbone-14 et du Tritium a l'Aide d'un Spectrometre a Scintillateurliquide: Extinction Chromatique; Izmerenie soderzhaniya Ugleroda-14 i Vodoroda-3 s pomoshch'yu zhidkostnogo stsintillyatsionnogo spektrometra. oslablenie tsveta; Influencia de la Extincion Cromatica en la Medicion del Carbono-14 y del Hidrogeno-3 por Espectrometria del Centelleo Liquido

    Energy Technology Data Exchange (ETDEWEB)

    Iwakura, T.; Kasida, Y. [National Institute of Radiological Sciences, Chiba (Japan)

    1965-10-15

    An attempt was made to correlate colour quenching and wavelength of the absorption maximum in liquid scintillators. Attempts were also made to find a difference in discriminator ratio versus counting efficiency curves between chemical and colour quenching. Fourteen photosensitive cyanine dyes were used as colouring agents in alcohol solution. The concentration of the dye in the counting samples ranged from 0.5 to 10 x 10{sup -6} M to give the desired absorbance in the liquid scintillator medium. Toluene-1-{sup 14}C and toluene-{sup 3}H were used as the internal standards. Counting was carried out with a Packard TRI-CARB Model 314 EX2 liquid scintillation spectrometer. Discriminator settings were 100-1000 divisions for the red channel and 186-1000 divisions fox the green channel. The high voltage applied to the photomultiplier was selected to give balance point operation in the red channel in an unquenched sample. Concentration of dyes against extent of quenching was examined. Because of the characteristic wavelengths of light emitted by the scintillator systems and the response of the photomultipliers (S-11 response), it was expected that red and yellow solutions which have maximum absorption at 400-500 nm would show the greatest quenching effect. To evaluate the total colour quenching, the following relationship was used to define the total absorption coefficient: A = ({Sigma}A{sub i}W{sub i})/({Sigma}W{sub i}) where W{sub i} is the relative photomultiplier sensitivity for light within the spectral range i nm, and A{sub i} is the absorbance of light within the spectral range i nm used. Total absorbance was calculated for each 40 nm range. 360-400, 400-440 etc., to 520-560 nm. The reciprocal absorbance 1/A versus the counting efficiency shows a linear relationship over a wide range of counting efficiencies. The curves of the discriminator ratio versus counting efficiency show that when colour quenching becomes strong, the colour quenching curve separates from the chemical quenching curve in {sup 14}Ccounting. On the other hand, similar measurements made in counting {sup 3}H do not show a separation of the two quenching curves. (author). (author) [French] On s'est efforce de trouver une correlation entre l'extinction chromatique et la longueur d'onde d'absorption maximale des scintillateurs liquides. On a egalement cherche a trouver une difference entre les courbes exprimant l'efficacite du comptage en fonction du rapport du discriminateur, selon qu'il s'agit d'extinction chimique ou d'extinction chromatique. On a utilise comme colorants 14 cyanines photosensibles en solution alcoolique. On a fait varier la concentration de teinture dans les echantillons de comptage de 0,5 a 10x10{sup -6} M, de maniere a obtenir le pouvoir absorbant voulu dans le scintillateur liquide. Du toluene-1- 14C et du toluene-3 H ont servi d'etalons internes. On a procede au comptage avec un spectrometre a scintillateur liquide Packard TRI-CARB, modele 314 EX2. Les reglages du discriminateur etaient les suivants: 100 a 1000 divisions pour le canal rouge et 186 a 1000 divisions pour le canal vert. La haute tension appliquee au photomultiplicateur a ete choisie de maniere a obtenir le point d'equilibre dans le canal rouge pour un echantillon non eteint. On a etudie les concentrations des teintures en fcuction du degre d'extinction. En raison des longueurs d'onde caracteristiques de la lumiere emise par le scintillateur et de la reponse des photomultiplicateurs (reponse S-ll), on s'attendait que les solutions rou,geb et jaunes qui accusent une absorption maximale a 400-500 nm donnent l'effet d'extinction le plus prononce. En vue de calculer l'extinction chromatique totale, on a utilise la formule suivante pour determiner le coefficient d'absorption totale: A = ({Sigma}A{sub i}W{sub i})/({Sigma}W{sub i}), dans laquelle W{sub i} est la sensibilite relative du photomultiplicateur pour une lumiere emise sur une longueur d'onde de i nm et A{sub i} est le coefficient d'absorption de la lumiere emise sur la longueur dlonde de i nm dans la bande spectrale utilisee. On a calcule le coefficient d'absorption totale pour chaque bande de 40 nm soit 360-400, 400-440, etc. jusqu'a 520-560 nm. Le graphique de l'inverse du coefficient d'absorption 1/A en fonction de l'efficacite du comptage revele une relation lineaire pour un large intervalle d'efficacite de comptage. Les courbes donnant le rapport du discriminateur en fonction de l'efficacite de comptage montrent que, lorsque l'extinction chromatique devient forte, la courbe qui la represente se separe de la courbe d'extinction chimique dans le comptage de {sup 14}C. Au contraire, des mesures analogues faites avec {sup 3}H ne font pas apparaitre cette separation entre les courbes d'extinction. (author) [Spanish] Los autores procuraron establecer una relacion entre la extincion cromatica y la longitud de onda en el maximo de. absorcion de centelleadores liquidos. Asimismo intentaron hallar una diferencia en la razon de discriminacion en funcion de las curvas del rendimiento de recuento entre la extincion qufmica y la cromatica. Utilizaron 14 colorantes fotosensibles a base de cianina en solucion alcoholica. La concentracion del colorante en las muestras que se querfan analizar estaba comprendida entre 0,5 y 10 x 10{sup -6} M fin-de obtener la absorcion deseada en el centelleador liquido. Como patrones internos emplearon tolueno-1- {sup 14}C y tolueno-{sup 3}H. El recuento se efectuo con un espectrometro de centelleo liquido Packard TRI-CARB, modelo 314 EX2. El discriminador se graduo en 100 a 1000 divisiones para el canal rojo y en 186 a 1000 divisiones para el canal verde. El valor de la alta tension aplicada al fotomultiplicador se eligio con miras a conseguir un funcionamiento en el punto de equilibrio del canal rojo para una muestra sin extintor. Los autores estudiaron la concentracion de colorantes en funcion del grado de extincion. Debido a la longitud de onda caracteristica de la luz emitida por los centelleadores y la respuesta del fotomultiplicador (S-ll), se supuso que la solucion roja y amarilla, que tiene un poder maximo de absorcion a 400-500 nm, ejerceria el efecto de extincion mas acusado. Para evaluar la extincion cromatica total el coeficiente de absorcion total se definio mediante la expresion A = ({Sigma}A{sub i}W{sub i})/({Sigma}W{sub i}), donde W{sub i} es la sensibilidad relativa del fotomultiplicador a luz de una longitud de onda i nm y A{sub i} es la absorbencia de luz de longitud de onda i nm en el intervalo espectral empleado. La absorbencia total se calculo para una serie de intervalos de 40 nm (360 a 400 , 400 a 440, etc., hasta 520 a 560 nm). La inversa de la absorbencia (1/A) es proporcional al rendimiento de recuento de un amplio intervalo de valores de este. En el recuento del {sup 14}C, las curvas de la razon de discriminacion en funcion del rendimiento de recuento ponen de manifiesto que a medida que se intensifica la extincion cromatica, la curva correspondiente se separa de la curva de extincion qufmica. Por otra parte, mediciones similares efectuadas durante el recuento de {sup 3}H no revelan separacion de las dos curvas de extincion. (author) [Russian] Byla sdelana popytka ustanovit' sootnoshenie mezhdu oslableniem cveta i dlinoj volny maksimuma pogloshhenija v zhidkostnyh scintilljatorah. Byla takzhe sdelana popytka opredelit' razlichija krivyh zavisimosti kojefficienta diskriminatora ot jeffektivnosti scheta dlja himicheskogo oslablenija i oslablenija cveta. Chetyrnadcat' fotochuvstvitel'nyh cianinovyh krasok bylo ispol'zovano v kachestve krasjashhih agentov v rastvore spirta. Koncentracija kraski v izmerjaemyh obrazcah menjalas' ot 0,5 do 10-10{sup 6} molja, chtoby poluchit' trebujushheesja pogloshhenie v zhidkoj scintilljacionnoj srede. V kachestve vnutrennih standartov ispol'zovalis' toluol-1-uglerod-14 i toluol- vodorod-3. Schet proizvodili s pomoshh'ju zhidkostnogo scintilljacionnogo spektrometra Pakard TRI-CARB, model' 314 EH2. Nastrojka diskriminatora sostavljala 100-1000 delenij dlja krasnogo kanala i 186-1000 delenij dlja zelenogo. Vysokoe naprjazhenie, primenjaemoe dlja fotoumnozhitelja, vybrali dlja togo, chtoby obespechit' uravnoveshennuju tochechnuju rabotu v krasnom kanale pri neoslablennom obrazce. Koncentracija krasok byla izuchena po stepeni oslablenija. Vsledstvie harakternosti dliny voln sveta, ishodjashhego iz scintilljatornyh sistem i reakcii fotoumnozhitelej (reakcija S-I), predpolagalos', chto krasno-zheltyj rastvor, kotoryj imeet maksimum pogloshhenija pri 400 - 500 mmk budet imet' samyj bol'shoj jeffekt oslablenija. Chtoby ocenit' obshhee oslablenie cveta dlja opredelenija kojefficienta obshhego pogloshhenija ispol'zovalos' sledujushhee otnoshenie: A = ({Sigma}A{sub i}W{sub i})/({Sigma}W{sub i}), gde W{sub i} - otnositel'naja chuvstvitel'nost' fotoumnozhitelja k svetu s dlinoj volny i mmk; a A{sub i} - pogloshhenie sveta s dlinoj volny i mmk v predelah ispol'zuemogo spektra. Obshhee pogloshhenie bylo rasschitano dlja kazhdogo intervala v 40 mmk, naprimer dlja 360 - 400, 400 - 440 i t.d. do 520 - 560 mmk. Jekvivalentnoe pogloshhenie 1/A v zavisimosti ot jeffektivnosti scheta pokazyvaet linejnuju zavisimost' v shirokom diapazone jeffektivnosti scheta. Krivye zavisimosti kojefficienta diskriminatora ot jeffektivnosti scheta pokazyvajut, chto, kogda oslablenie cveta stanovitsja sil'nym, krivaja oslablenija cveta otdeljaetsja ot krivoj himicheskogo oslablenija pri schete ugleroda-14. S drugoj storony, proizvedennye pri schete vodoroda-3 analogichnye izmerenija ne pokazyvajut razdelenija dvuh krivyh oslablenija. (author)

  18. International Symposium on Gas Kinetics (9th) Held in Bordeaux, France on 20-25 July 1986. Abstracts

    Science.gov (United States)

    1986-07-25

    versidad a Distancia, Ciudad Universitaria, 28040 Madrid. 3.M. Fiquera, J. Medina and 3.C. Rodriguez, Int de Quimica Fi sica "Rocasolano", CSIC, Serrano...inhibition. N J3 By making sensible (we hopel) assumptions about the reactivity of C 2115 towards allylic It, we estimate for 798 K and 50 Torr n-hexane

  19. Localization and Specification of Copper Ions in Biofilms on Corroding Copper Surfaces.

    Science.gov (United States)

    1994-01-01

    Sao Paulo, Brazil: Aquatec Quimica : 1985). 256/3 5. H. Shih, F. Mansfeld, ASTM STP 1154, 174, Philadelphia, PA, 1992. 6. B. Little, P. Wagner, R...Pope, "A Study of Microbiologically Influenced Corrosion in Nuclear Power Plants and a Practical Guide for Countermeasures," Electric Power Research

  20. Sol-Gel Optics: Proceedings SPIE-The International Society for Optical Engineering Held in San Diego, California on 11-13 July 1990. Volume 1328

    Science.gov (United States)

    1992-03-01

    important for optical devises used in such environment as nuclear power stations and space stations. Fig. 9 shows the y-ray dose dependence of the coupling...Bi 2 0 3 and TiO2-CeO 2 Compositions. Michel A. Aegerter, Eliane R. La Serra University of Sao Paulo, Instituto de Fisica e Quimica de Sao Carlos

  1. Molecular Recognition in the Oxidation of Catechols by Dicobalt-BISDIEN Dioxygen Complexes

    Science.gov (United States)

    1992-01-30

    Recognition in the Oxidation of Catechols by Dicobalt-RISDIEN Dioxygen Complexes Lizete F S Cezar and Bruno Szpoganicz Departamento de Quimica ...bridged bi- nuclear Co(II)-BISDIEN dioxygen complexes; Co20 2 LCat2 + is the bivalent form, and Co20 2 (OH)LCat + and Co 20 2 (OH)2 Cat° are hydroxo

  2. International Symposium on Solubility Phenomena (3rd) Held in Guildford, Surrey England on 23 - 26 August 1988

    Science.gov (United States)

    1988-08-26

    solubilities is, first of all, important for metallurgy, electrochemistry, nuclear and space technology. Experimental solubilities of metals in liquid Hg...Dianderas de Acosta and I.FernAndez Paz Departamento de Quimica Universidad Nacional de San Agustin, Arequipa, Peru Equilibria and derived free

  3. Soldier-Portable Battery Supply: Foreign Dependence and Policy Options

    Science.gov (United States)

    2014-01-01

    private firm, the Sociedad Quimica y Minera (SQM) de Chile. Across the border in Bolivia, the Salar de Uyuni, which is the largest salt flat in the...on analyzing the U.S.-China military balance, as well as developing strategies for dealing with nuclear -armed regional adversaries and performing an

  4. Dynamics of Electron Transfer for a Nonsuperexchange Coherent Mechanism. I

    Science.gov (United States)

    1989-10-13

    observation. In the treatment three collective nuclear coordinates are introduced, permitting independent reorganization energies for each reactive center... nuclear coordinates are introduced, permitting independent reorganization energies for each reactive center. With certain approximations, namely, equal...numerically. One rough but simple analytical result for the latter is also given. tPresent address: Departmento de Quimica , Facultad de Ciencias

  5. Binding of Pentaammineruthenium(II) Residues to the Tris(bipyrazine)ruthenium(II) Cation.

    Science.gov (United States)

    1987-08-01

    de Quimica , Universidade de Sao Paulo, CP 20780, Sao Paulo, SP, Brazil and Department of Chemistry, York University, North York, Ontario, Canada M3J...absorption spectra in the near-infrared region were obtained with a Cary 1 7 spectrophotometer, with the samples dissolved in D20. Nuclear magnetic

  6. Theoretical Crystal-Field Calculations for Rare-Earth Ions in III-V semiconductor Compounds

    Science.gov (United States)

    1991-10-01

    22209 Director Director US Army Electronics Warfare Laboratory Defense Nuclear Agency Attn AMSEL-DD Attn Tech Library Attn AMSEL-DD, J. Charlton 6801...Washougal, WA 98671 Attn SLCHD-NW-TN, Chief Attn SLCHD-NW-TS, Chief Departmento Quimica Fundamental Attn SLCHD-PO, Chief Universidade Federal de

  7. Interfacial Effects and Organization of Inorganic-Organic Composite Solids.

    Science.gov (United States)

    1998-05-20

    alkoxide are examined by liquid state 29Si nuclear magnetic resonance)NMR) spectroscopy. The morphology of the coating is dependent upon chemical...Lopez, Univ de Malaga, Dept d* Quimica Inorganica, CnatalograAa It Mineralogia Malaga, SPAIN; Deborah Jones, Univ de Montpellier II, Lab dei

  8. Particle Flux in the Western Black Sea in the Present and over the Last 5,000 Years: Temporal Variability, Sources, Transport Mechanisms.

    Science.gov (United States)

    1987-09-01

    unit i in the deep basil o,’res is 263 rm. Thus, based on this calculation the annua! deposition at the suGre sites is on average 4.7 times higher than...AAS) y espectrografia de emision (OES): Anales de Quimica, v. 81, p. 48-55. % %. -131- Baumgartner, T., V. Ferreira-Bartrina, H. Schrader, and A

  9. A Simple DWBA (’Franck-Condon’) Treatment of H-Atom Transfers between Two Heavy Particles.

    Science.gov (United States)

    1984-07-02

    integral over the reactants’ and products’ wavefunctions and the interaction potential. )Permanent address: DIpartarnento de Quirnica Fisica y Quimica... Cuantica , USniversidad Autonomna de Madrid, Cantoblanco. Madrid-34, Spain. blContribution No. 7020. -2- The reactants’ and products’ wavelunctions

  10. 1738-IJBCS-Article-Saw Yaya

    African Journals Online (AJOL)

    hp

    the “Instituto de Quimica, -(U.N.A.M),. Mexico” - while Mössbauer spectra were obtained as described previously (DE Sousa et al., 2006). The infrared spectra were obtained with FTIR spectrometer, the samples being as. KBr pellets. Infrared data are given in cm-1. IR abbreviations: (vs) very strong, (s) strong, (m) medium ...

  11. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    1 Fernando Ibañez1 Lucio Valetti1 Vanina Muñoz1 María Soledad Anzuay1 Liliana Ludueña1 Adriana Fabra1. Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-quimicas y Naturales, Universidad Nacional de Río ...

  12. Measurements of sulfur dioxide, ozone and ammonia concentrations in Asia, Africa, and South America using passive samplers

    CSIR Research Space (South Africa)

    Carmichael, GR

    2003-03-01

    Full Text Available : gcarmich@engineering.uiowa.edu (G.R. Carmichael). 1352-2310/03/$ - see front matter r 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S1352-2310(02)01009-9 ac Chemistry Istitute Departmento de Quimica Analitica, Universidade Federal da Bahia...

  13. International Conference on Internal Friction and Ultrasonic Attenuation in Solids (ICIFUAS) (10th) held in Roma, Italy on September 6 - 9, 1993

    Science.gov (United States)

    1993-09-09

    Flortncio 3. H. Tejima 3 , J.A.R. Jordao3 (1) Depto de Fisica, UNESP, Bauru, SP, Brazil. (2) Depto Engenharia Mateiais, UFSCar. Sao Carlos, SP, Brazil. (3...At6mica, Dto. de Quimica de Reactores, Av. del Libertador 8250, (1429) Buenos Aires, Argentina. (3) Universidad de Buenos Aires, Facultad de Ciencias

  14. Source Hierarchy List. Volume 3. O through Z

    Science.gov (United States)

    1994-07-01

    UNIVERSIDAD NACIONAL DE CORDOBA 387102 (ARGENTINA) 01 UNIVERSIDAD NACIONAL DE CORDOBA 4O5530 (ARGENTINA) INSTITUTO DE CIENCIAS QUIMICAS ...UNIVERSIDADE ESTADUAL DE CAMPINAS 426597 (BRAZIL) 01 UNIVERSIDADE ESTADUAL DE CAMPINAS (BRAZIL) FACULDADE DE ENGENHARIA * 5133 398130 UNIVERSIDADE...UNIVERSIDADE FEDERAL DE SAD CARLOS 420497 (BRAZIL) 01 UNIVERSIDADE FEDERAL OE SAO CARLOS (BRAZIL) OEPT OE ENGENHARIA DE MATERIALIS

  15. Materials for Energy Conversion and Environmental Protection

    Science.gov (United States)

    2004-10-13

    electrochemistry group, head of the inorganic chemistry department, and a member of the Instituto de Quimica -Fiscia de los Materiales, Medio Ambiente y...at Worcester Polytechnic University and received his B.S. in chemical engineering in1982 from the Instituto Militar de Engenharia (Brazil), and his

  16. Planetary Conjunction: Economics, Politics, and Partnering In Space

    Science.gov (United States)

    2013-06-01

    Andrade Gutierrez Quimica Ltda, Centro Tecnico Aerospacial, Empresa Brasileira de Telecomunicacões, Instituto de Aeronautica e Espaco, and Instituto...Activity (EVA) During Space Transportation System (STS) -82, a Servicing Mission for the Hubble Space Telescope (HST).........................33 13...responsible for the solar array that would power Hubble while in orbit.63 Figure 12: An Extravehicular Activity (EVA) During Space Transportation

  17. (AJST) DETERMINATION DE LA QUALITÉ DU PAIN DE SUCRE A ...

    African Journals Online (AJOL)

    RÉFÉRENCES. Arguello-Morales, M., Sanchez-Gonzales, M., Canedo, M.,. Quirasco, M., Farres, A., Lopez-Munguia, A., (2005),. Proteolytic modification of Leuconostoc mesenteroides B-512F dextransucrase, Antonie Van. Leewenhoek, 87(2):131-141. Badui, J.D.S., (1995), Quimica de alimentos, 3a edicion,. 62-65, Edition ...

  18. Original Research Original Research

    African Journals Online (AJOL)

    RAGHAVENDRA

    Argon, G.T. (1986). Estudo geoquimico de metais pesados em sediments da planicie de mare da Enseada das. Garcas. Baia de Sepetiba. RJ.T.Mest., Inst. Quimica,. Univ.fed. Fluminense. 135. Berrow, M.L. and Stein, W.M. (1983). Extraction of metals from soils and sewage by refluxing with aqua regia. Analyst 108: 277-285 ...

  19. Human immunodeficiency virus (HIV) seropositivity and hepatitis B ...

    African Journals Online (AJOL)

    Method: A total of 130 donors comprising 120 commercial donors and 10 voluntary donors were tested for antibodies to human immunodeficiency virus and hepatitis B surface antigen in Benin city using Immunocomb HIV - 1 and 2 Biospot kit and Quimica Clinica Aplicada direct latex agglutination method respectively.

  20. Metal–selenium interactions. Crystal structure of binuclear [( 1η-iodo ...

    Indian Academy of Sciences (India)

    Unknown

    2Departmento de Quimica Inorganica, Facultade de Farmacia, Universidade de Santiago, 15706, Santiago, Spain e-mail: tarlok@angelfire.com. MS received 11 September 2000; revised 13 November 2000. Abstract. Reaction of mercury(II) diiodide with triphenyl selenophosphorane–Se. (1:1 mole ratio) in acetone followed ...

  1. JPRS Report, Proliferation Issues

    Science.gov (United States)

    1992-06-25

    control of INGTON POST saying: "Secretary of Defense Richard Nuclemon Minero Quimica Ltda. [Nuclebras Monazite and Cheney approved the Pentagon’s plan ... Planned [Alm a-Ata Radio] .................................................................................................. 26 Krasnoyarsk Search for...34 [Article by political staff: "Space plan defended"] He said the aim of the investigation was to determine the market opportunities, risks and

  2. NEWS: Conference diary

    Science.gov (United States)

    2000-03-01

    18 - 20 October 2000 Santa Fe, Argentina 5th Symposium of Investigators in Physics Education. Info: Ing Cristina Camara, GIDEAF Departamento de Fisica, Facultad de Ingenieria Quimica - UNL, Santiago del Estero 2829, 3000 Santa Fe, Argentina (ccamara@fiqus.unl.edu.ar or www.unl.edu.ar/sief5 )

  3. Characterization of magnetic nano particles of CoFe{sub 2}O{sub 4} and CoZnFe{sub 2}O{sub 4} prepared by the chemical co-precipitation method; Caracterizacion de nanoparticulas magneticas de CoFe{sub 2}O{sub 4} y CoZnFe{sub 2}O{sub 4} preparadas por el metodo de coprecipitacion quimica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, J.; Zambrano, G.; Gomez, M. E. [Universidad del Valle, Departamento de Fisica, Laboratorio de Peliculas Delgadas, Ciudad Universitaria Melendez, 25360 Cali (Colombia); Prieto, P. [Universidad del Valle, Centro de Excelencia en Nuevos Materiales, Ciudad Universitaria Melendez, 25360 Cali (Colombia); Espinoza B, F. J., E-mail: javierlo21@gmail.com [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Fracc. Real de Juriquilla, 76230 Queretaro (Mexico)

    2012-07-01

    Magnetic cobalt ferrite nanoparticles of CoFe{sub 2}O{sub 4} and CoZnFe{sub 2}O{sub 4} were prepared by co-precipitation technique from aqueous salt solutions of Co (II), ZnSO{sub 4} and Fe (III), in an alkaline medium. CoFe{sub 2}O{sub 4} powder samples were structurally characterized by X-ray diffraction, showing the presence of the most intense peat at 2{theta} = 413928{sup o} (Co K{alpha}1) corresponding to the (311) crystallographic orientation of the CoFe{sub 2}O{sub 4} spinel phase. The mean size of the crystalline of CoFe{sub 2}O{sub 4} and CoZnFe{sub 2}O{sub 4} nanoparticles determined from the full width at half maximum of the strongest reflection of the (311) peak by using the Scherrer approximation was calculated to be 11.4 and 7.0 ({+-} o.2) nm, respectively. Transmission electron microscopy studies permitted determining nanoparticle size of CoZnFe{sub 2}O{sub 4}. Fourier transform infrared spectroscopy was used to confirm the formation of Fe-O bonds, allowing identifying the presence of ferrite spinel structure. Magnetic properties were investigated with the aid of a vibrating sample magnetometer at room temperature Herein, the sample showed superparamagnetic behavior, determined by the hysteresis loop finally, due to the hysteresis loop of the CoZnFe{sub 2}O{sub 4} is very small, our magnetic nanoparticles can be considered as a soft magnetic material. These magnetic nanoparticles have interesting technological applications in biomedicine given their biocompatibility, in nano technology, and in ferro fluid preparation. (Author)

  4. Determinação espectrométrica dos flavonóides das folhas de Maytenus (Celastraceae e de Passiflora (Passifloraceae e comparação com método CLAE-UV

    Directory of Open Access Journals (Sweden)

    Regina de A. O. Chabariberi

    Full Text Available Este trabalho apresenta uma modificação dos procedimentos descritos nas Farmacopéias Francesa e Européia para a análise de flavonoides de Passiflora incarnata L., Passifloraceae, por espectrometria UV-Visível e propõe a sua aplicação na determinação dos flavonoides totais das folhas da espinheira-santa (Maytenus aquifolium Mart. e Maytenus ilicifolia (Schrad. Planch., Celastraceae e do maracujá (Passiflora edulis Sims. e Passiflora alata Curtis, Passifloraceae. Os resultados obtidos por espectrometria no UV-Visível foram comparados aos obtidos por cromatografia líquida de alta eficiência (CLAE-UV, encontrando-se resultados estatisticamente similares entre os métodos espectrométrico modificado da Farmacopéia Francesa e CLAE-UV.

  5. Production and Use of the Isotopes Sodium-24, Potassium-42, Copper-64 and Molybdenum-99; Production et Utilisation des Isotopes Sodium-24, Potassium-42, Cuivre-64 et Molybdene-99; ПРОИЗВОДСТВО И ПРИМЕНЕНИЕ ИЗОТОПОВ НАТРИЯ-24, КАЛИЯ-42, МЕДИ-64 И МОЛИБДЕНА-99; Produccion y Empleo los Isotopos Sodio-24, Potasio-42, Cobre-64 Y Molibdeno-99

    Energy Technology Data Exchange (ETDEWEB)

    Loos, R. [Departement de Physique, Universite Lovanium, Leopoldville (Congo, The Democratic Republic of the)

    1963-03-15

    }s en el punto de flujo maximo). Como se carece de medios de manipulacion quimica para las sustancias muy activas, se procede a irradiar muestras consistentes en productos quimicos de forma adecuada ; la ausencia de isotopos no deseables se comprueba por espectrometria gamma (analizador de 400 canales). Los recuentos se efectuan generalmente con analizadores de un solo canal. En el caso del cobre-64 ciertas mediciones se han controlado con un dispositivo de dos detectores en coincidencia. Se ha previsto el empleo del analizador multicanal para los experimentos en que intervengan dos indicadores. El autor senala algunos de los fines para que se emplean los radioisotopos: 1. En el laboratorio de fisiologia: curvas de flujo circulatorio, distribucion y cinetica de la distribucion de diversos isotopos (sodio-24, potasio-42, cobre-64). 2. En el laboratorio de farmacologia: influencia de diversas condiciones farmacologicas sobre los desplazamientos de los iones (potasio-42); fijacion del cobre-64 por los musculos lisos y sus relaciones con la actividad farmacologica de este metal. 3. En el laboratorio de microbiologia: estudio de l'a*funcion fisiologica y de la distribucion delmolibdeno en las plantas (molibdeno-99); control del perfeccionamiento de metodos microbiologicos para la determinacion del molibdeno. (author) [Russian] Leopol'dvil'skij universitet Lovanium rabotaet v tesnom sotrudnichestve s centrom Triko, kotoryj raspolagaet reaktorom Triga (DheNjoral Atomiks) s maksimal'noj moshhnost'ju v 50 kvt i postavljaet izotopy laboratorijam universiteta ili drugim potrebiteljam. Kak pravilo, obluchenie proizvoditsja v rotacionnoj korone (plotnost' potoka 3,10{sup 11}n/sek.sma); v special'nyh sluchajah ispol'zuetsja central'nyj kanal (2,5 * 10{sup 12}n/sek cm{sup 2} pri maksimal'noj plotnosti potoka). V svjazi s otsutstviem sredstv himicheskoj obrabotki vysoko aktivnyh veshhestv pribegaet k oblucheniju obrazcov v sootvetstvujushhej himicheskoj forme; otsutstvie izotopov s

  6. European Science Notes Information Bulletin Reports on Current European/ Middle Eastern Science

    Science.gov (United States)

    1991-03-01

    carbon-fibre- reinforced plastic Centro de Quimica Fisica Molecular P composites Deutsche Forschungsanstalt fur Luft-Und Raumfahrt (DLR), K61n-Porz D...technology R&D is a significant part of this program, Nuclear and Renewable Energies (ENEA), and eight funded at about DM 550 ($314.3 million). Coal... nuclear powerplants. The process is being and to experimentally employ new communication tested in a plant of industrial scale where the resins are

  7. Thin Metallic Films from Solvated Metal Atoms.

    Science.gov (United States)

    1987-07-14

    Departamento de Quimica , Universidad de Concepcion, Cassilla 3-:, c oncepcion, Chile. -I{ - ~ *~.’JS*~M 4 .~4\\ 821 19 the gold particles were negatively...1:i, 7 J. AdpI. Radiat. s toD.. 21(l),36-8 (1970). 12. L. G. Colombetti, D. A. Goadwin, and R. J. Hermanson, Nuclear Aed. 10, 597-6u2. (1C69). 13. L

  8. Problem Definition Study on TAX (1-acetylhexahydro-3,5-dinitro-1,3,5- triazine), SEX (1-acetyloctahydro-3,5,7-trinitro-1,3,5,7-tetrazocine), Lead Salicylate and Lead Beta-Resorcylate 2-Nitrodiphenylamine and Ethyl Centralite

    Science.gov (United States)

    1979-07-01

    IV-14 IV-3. Nuclear Magnetic Resonance Spectrum of 2-Nitrodiphenylamine ................. IV-15 IV-4. Map of Radford Army Amumunition Plant...Chemie GmbH Chemische Werke Munchen Otto Barlocher CmbH Metallgesellschaft AG ITALY Stabilital SpA SPAIN Industrias Quimicas de Parets. SA UNITED KINGDOM...abnormal cristae and matrix, and disrupted nuclear membrane. The mitochrondria seemed to be the organelle most frequently affected. Thus, it was shown that

  9. Symposium Q: Magnetic Thin Films, Heterostructures, and Device Materials

    Science.gov (United States)

    2007-05-22

    ing, and applications. version, hydrogen, and nuclear research. Examples of extended functionality of In addition to the presentations on government...and the pure Fe is bcc phase. United States Department of Energyi National Nuclear Security From these evidences, it indicates that the laminates form...in the regions where the self assembled monolayer is polar in Escudero3; ’Centro de Investigacion en Quimica Aplicada, Saltillo, nature, and it is non

  10. Lipopolysaccharide Antigens of Pseudomonas aeruginosa and Design of Novel Vaccines.

    Science.gov (United States)

    1987-09-01

    Studies on the Lipopolysaccharide Antigens of Seven Immunotypes of P a_ n , SELAQ, Proc. 3 VL Seminario Latinoamericano J1 Quimica , pp. 143-159 (1979). 7...Bioolymers, 19 (1980) 1801-1814. 74" , 8. Derek Horton and David A. Riley, Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy of Lipopolysaccharides...Amer. Chem. Soc., 87 (1965), 1345-1353. 40. D. Horton and D. A. Riley, "Phosphorus-31 Nuclear Magnetic Resonance Spectroscopy of Lipopolysaccharides

  11. Microbiologically Influenced Corrosion in Copper and Nickel Seawater Piping Systems

    Science.gov (United States)

    1990-09-01

    Influenced Tipton, D. G. and Kain, R. M. 1980. Effect of temperature onCorosiope in Nuclear Power Plants atudy a Mical Gnuide the resistance to pitting of...Monel alloy 400 in seawater. In:Corrosion in Nuclear Power Plants anda Practical ie fr Proceedings of Corrosion 󈨔. Chicago, Illinois: National...Sons Ltd. 441 pp. Quimica . Verink, E.D. and Pourbaix, M. 1971. Use of electrochemical Pope, D. H., Duquette, D. J., Johannes, A. H., and Wayner

  12. Colloquium on High Resolution Molecular Spectroscopy (16th) Held in Universite de Bourgogne, Dijon, France on 6-10 September 1999

    Science.gov (United States)

    1999-09-28

    Chimica Fisica e Photophysique Mol6culaire, Physikalische Chemnie, Inorganica, Universit6 de Paris-Sud, ETH Zentrum, Universitý, de Bologna, Orsay... de la Materia, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid, Spain; C. CLAVEAU and A. VALENTIN, Laboratoire de Physique...Cedex, France; J. C. LOPEZ and S. BLANCO, Departamento de Quimica- Fisica , Facultad de Ciencias, Universitad de Valladolid, 47071 Valladolid, Spain; A

  13. International Conference on Chemical Kinetics: Program and Abstracts Held in Gaithersburg, Maryland on 17-19 June 1985.

    Science.gov (United States)

    1985-06-01

    Salamanca Dpto. Fisica Teorica and University Complutense Dpto. Metodos Matematicos de la F1sica The authors show how the knowledge of (n-1) first...M. Dominguez. Centro de Quimica, Instituto Venezolano de Investigaciones Cientificas Caracas 1010-A. Venezuela. The kinetics of the gas phase...Alexandra Rotinov, Rosa M. Domfnguez, and Ignacio Martin Centro de Qufmica, Instituto Venezolano de Investigaciones Cientificas (I.V.I.C.), Caracas

  14. International Symposium (43rd) on Molecular Spectroscopy Held in Ohio State University on 13-17 June 1988.

    Science.gov (United States)

    1988-06-01

    Superior de Investigaciones Cientificas, c/Serrano, 119, 28006 Madrid, Spain. TG7. ON THE ASSIGNMENT OF THE EXCITED SINGLET STATES IN THE CO. MOLECULE...Departmento de Quimica Fisica , Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain; and R. H. TIPPING, Department of Physics and Astronomy...Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, C/ Serrano, 119, 28006 Madrid, SPAIN. ’-. (2:𔃻) ON THE ASSIGNMENT

  15. Recursos humanos para novos cenários Human resources for new scenarios

    Directory of Open Access Journals (Sweden)

    Angelo C. Pinto

    2009-01-01

    Full Text Available The Brazilian Chemical Society - SBQ has made substantial contributions to the formation of qualified human resources at all levels since its foundation in 1977. Several papers addressing this subject have been published in Quimica Nova by different authors over the last years. In this paper, we discuss the present need for "Curriculum Guidelines" for undergraduate education in Chemistry with actions to be taken in accord with the Principles of Green Chemistry and Sustainability.

  16. Proceedings of US-Latin American Workshop on Molecular and Materials Sciences: Theoretical and Computational Aspects Held in Gainesville, Florida on 10-12 March 1993

    Science.gov (United States)

    1994-08-09

    QUJANTM OIGMI CAL CALCULATI OCS APPLI ED TO A RAT7 ONAL DESIGN OF METAL CATALYSTS. Guillermina Lucia EstiO. Proyecto Qui nor. Facultad de Ciencias ...Necanica Cuantica Aplicada (CNCA). Facultad do Ciencias , Universidad de Chile, Casilla 653-Santiago Chile. Keywords : Ion Solvation Isoelectronic Processes...Vmnezolano de Invetigaciones Cientificas (MC), Apartado 21827, Caracas 1020-A, Venmeuela and Escuela do Quimica, Facultad de Ciencias , Universidad

  17. 20th International Conference on Solid State Ionics (SSI 20)

    Science.gov (United States)

    2016-05-20

    Italy; 2CNST @PoliMI, Istituto Italiano di Tecnologia , Milano, Italy; 3Physical Chemistry of Solids, Max Planck Institute for Solid State Research...Coughlin5; 1Chemical Sciences, University of Padova, Padova, Italy; 2Consorzio Interuniversitario Nazionale per la Scienza e la Tecnologia dei Materiali...Germany; 2Instituto de Tecnologia Quimica , Valencia, Spain; 3Ernst Ruska Center, Jülich, Germany. 4:50 PM J5.05 Hydrogen Permeation through CO2-Stable

  18. A IMPORTÂNCIA DA SOCIEDADE BRASILEIRA DE QUÍMICA NA PÓS-GRADUAÇÃO EM QUÍMICA NO BRASIL

    Directory of Open Access Journals (Sweden)

    Aldo J. G. Zarbin

    Full Text Available The role of the different actions headed by the Brazilian Chemical Society (SBQ for the development of the Graduate Programs in Chemistry in Brazil is highlighted herein. Specifically, the importance of the SBQ journals, such as the Quimica Nova (QN, Journal of the Brazilian Chemical Society (JBCS and Revista Brasileira de Química (RVQ as vehicles to disseminate the knowledge produced by the different graduate programs in chemistry is demonstrated.

  19. Brazil, the United States, and the Missile Technology Control Regime

    Science.gov (United States)

    1990-03-19

    Pursues Dream in Space," Washington Post, 13 December 1984, lf, 4f. According to Defense News, "Brazil’s Andrade Gutierrez Quimica produces ammonium...owned by Engesa (EnQenheiros Especializados S.A. - 40 percent), Embraer (Empresa Brasileira de Aeronautica S.A. - 40 percent), Esca ( Engenharia de...AeronAutica S.A. EMFA - Estado Maior das Forcas Armadas (General Staff of the Armed Forces) Engesa - Engenheiros Es~ecializados S.A. Esca - Engenharia de

  20. International Symposium on Applications of Laser Techniques to Fluid Mechanics (7th) Held in Lisbon, Portugal on July 11-14, 1994. Volume 1

    Science.gov (United States)

    1994-07-14

    CHARACTERISTICS OF LOW MOLECULAR WEIGHT SHEAR-THINNING FLUIDS A. S. Pereira Departamento de Engenharia Quimica , Instituto Superior de Engenharia do Porto Rua...de S.Tom6. 4200 Porto CODEX. Portugal F. T. Pinho Departamento de Engenharia Mecinica e Gestio Industrial Faculdade de Engenharia , Rua dos Bragas. 4099...turbulence Investiga•:’o Cientifica- INIC. INEGI (lnstituto de Engenharia characteristics of the low molecular weight polymers are Mec~nica e Gestio

  1. Proceedings of the Annual Conference on Magnetism and Magnetic Materials (38th) Held at Minneapolis, Minnesota on 15-18 November 1993. (Journal of Applied Physics. Volume 75, Number 10, Part 28

    Science.gov (United States)

    1994-05-15

    Spain E. Irurieta, J. Gonzilez, and K. Kulakowskia) Departamento de Fisica de Materiales, Facultad de Quimicas , Universidad del Pais Vasco, 20009...Ishikawa, and Doyle H Short period oscillation of the interlayer exchange coupling in sputtered Co-Re superlattices J. L. Leal Instituto de Engenharia de...1699 Lisbon, Portugal P. P Freitas Instituto de Engenharia de Sistemas e Computadores, R. Alves Redol, 9-1, 1000 Lisbon, Portugal and Instituto Superior

  2. 2-[3-Furyl(hydroxy)methyl]-2,3-dimethylcyclohexanone.

    Science.gov (United States)

    García, Esther; Mendoza, Virgilio; Guzmán, José Agustín; Maldonado Graniel, Luis Angel; Hernández-Ortega, Simón

    2002-06-01

    Contribution No. 1750 of the Instituto de Quimica, UNAM, Mexico. In the molecule of the title compound, C(13)H(18)O(3), there is a syn relationship between the two vicinal methyl groups. The six-membered ring adopts a chair conformation, with one equatorial and two axial groups, and the furyl group is almost parallel to the ketone group. Intermolecular hydrogen bonds [O[bond]H...O[double bond]C 2.814 (3) A] form chains along [100].

  3. Hidrólise do óleo de Azadirachta indica em água subcrítica e determinação da composição dos triacilglicerídeos e ácidos graxos por cromatografia gasosa de alta resolução a alta temperatura e cromatografia gasosa de alta resolução acoplada à espectrometria de massas Hydrolysis of Azadirachta indica oil using subcritical water and determination of triacylglycerides and fat acids by HT-HRGC-FID and HRGC-MS

    Directory of Open Access Journals (Sweden)

    Jair Sebastião da Silva Pinto

    2010-01-01

    Full Text Available The development of modern analytical tools plays an important role in quality control. The main purpose of this study was to explore the use of subcritical water as a versatile analytical tool, employed simultaneously as a reagent and solvent, as well as the application of high temperature-high resolution gas chromatography (HT-HRGC to develop a procedure for the analysis of triacylglycerides and fatty acids in Azadirachta indica A. Juss. (Neem oil without the need for solvents, chemical reagents, or catalytic agents. The developed method presented satisfactory results and is in agreement with the concepts of Green Analytical Chemistry (GAC.

  4. Physico-chemical characterization of human recombinant follicle-stimulating hormone (hFSH) and its subunits by reversed-phase high-performance liquid chromatography ( RP-HPLC): comparison with pituitary hFSH reference preparation from 'National Hormone and Pituitary Program' from USA; Caracterizacao fisico-quimica da foliculotropina humana(hFSH) recombinabte e de suas subunidades, por cromatografia liquida de alta eficiencia (HPLC) em fase reversa: comparacao com a preparacao de referencia de hFSH de origem hipofisaria do ''National Hormone and Pituitary Program'' dos EUA

    Energy Technology Data Exchange (ETDEWEB)

    Loureiro, Renan Fernandes

    2006-07-01

    A reversed-phase high-performance liquid chromatography (RP-HPLC) method for the qualitative and quantitative analysis of intact human folliclestimulating hormone (hFSH) was established and validated for accuracy, precision and sensitivity. Human FSH is a dimeric glycoprotein hormone widely used as a diagnostic analyte and as therapeutic product in reproductive medicine. The technique developed preserves the protein integrity, allowing the analysis of the intact heterodimeric form rather than just of its subunits, as it is the case for the majority of the conditions currently employed. This methodology has also been employed for comparing the relative hydrophobicity of pituitary, urinary and two Chinese hamster ovary (CHO)-derived hFSH preparations, as well as of two other related glycoprotein hormones of the anterior pituitary: human thyroid-stimulating hormone (hTSH) and human luteinizing hormone (hLH). The least hydrophobic of the three glycohormones analyzed was hFSH, followed by hTSH and hLH. A significant difference (p<0.005) was observed in t{sub R} between the pituitary and recombinant hFSH preparations, reflecting structural differences in their carbohydrate moieties. Two main isoforms were detected in urinary hFSH, including a form which was significantly different (p<0.005) for the pituitary and recombinant preparations. The linearity of the dose-response curve (r = 0.9965, n = 15) for this RP-HPLC methodology, as well as an inter-assay precision with relative standard deviation less than 4% for the quantification of different hFSH preparations and a sensitivity of the order of 40 ng, were demonstrated. The chromatographic behavior and relative hydrophobicity of the individual subunits of the pituitary and recombinant preparations were also analyzed. Furthermore, the accurate molecular mass of the individual hFSH subunits and of the heterodimer were simultaneously determined by matrix-assisted laser desorption ionization time-of-flight mass spectral analysis (MALDI-TOF-MS). The present methodology represents, in our opinion, an essential tool for characterization and quality control of this hormone that is not yet described in the main pharmacopoeias. (author)

  5. Obtention of agricultural gypsum traced on {sup 34} S (Ca{sup 34} SO{sub 4}.2H{sub 2}O), by chemical reaction between H{sub 2}{sup 34} SO{sub 4} and Ca(OH){sub 2}; Obtencao do gesso agricola marcado no {sup 34} S (Ca{sup 34} SO{sub 4}.2H{sub 2}O), por reacao quimica entre o H{sub 2}{sup 34} SO{sub 4} e Ca(OH){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Rossete, Alessandra L.R.M.; Bendassolli, Jose A.; Ignoto, Raquel de Fatima; Batagello, Hugo Henrique [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Isotopos Estaveis

    2002-07-01

    The gypsum (CaSO{sub 4}.2H{sub 2}O) has double function in the soil: as source of calcium and sulfur and reducing agent of aluminum saturation. The sulfur for the plants has acting in the vital functions and it is proven fact increase of the S deficiency in Brazilian soils. The isotope tracer {sup 34} S can elucidate important aspects in the sulfur cycle. The Ca{sup 34} SO{sub 4}.2H{sub 2}O was obtained by chemical reaction between Ca(OH){sub 2} and H{sub 2}{sup 34} SO{sub 4} solution. The acid was obtained by chromatography ionic change, using cationic resin Dowex 50WX8 and Na{sub 2}{sup 34} SO{sub 4} solution. The reaction was realized under slow agitation. After the reaction, the precipitate was separated and dried in ventilated stove at 60 deg C temperature. The Mass of the Ca{sup 34} SO{sub 4}.2H{sub 2}O produced was determined by method gravimetric. This way, a system contends resin 426 cm{sup 3}, considering volume of 2.2 liters can be obtained a solution contends 44.2 g of H{sub 2}{sup 34} SO{sub 4}, theoretically could be produced 78.0 g of Ca{sup 34} SO{sub 4}.2H{sub 2}O approximately. With results of the tests were verified that there was not total precipitation of the Ca{sup 34}SO{sub 4}.2H{sub 2}O. Were produced 73.7{+-} 0.6 g of Ca{sup 34} SO{sub 4}.2H{sub 2}O representing average income 94.6{+-}0.8 %. The purity of the produced CaSO{sub 4}.2H{sub 2}O was 98%. (author)

  6. Synthesis of Li{sub 1}+xM{sup I}II{sub x}Ti{sub 2}-x(PO{sub 4}){sub 3} with nasicon structure, using sol-gel methods. Study of the relationship microstructure electrical properties; Sintesis mediante quimica sol gel de compuestos Li{sub 1}+xM{sup I}II{sub x}Ti{sub 2}-x(PO{sub 4}){sub 3} con estructura tipo Nasicon. Estudio de la relacion microestructura-propiedades electricas

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Estebanez, M.; Rivera-Calzada, A.; Leon, C.; Santamaria, J.; Isasi-Marin, J.

    2010-07-01

    Compounds of formula Li{sub 1}+xM{sup I}II{sub x}Ti{sub 2}-x(PO{sub 4}){sub 3} with M{sup I}II = Cr, Fe and x = 0 and 0.05 have been prepared at soft temperatures using the Pechini synthesis method, based on sol-gel chemistry. The structural and microstructural characterization by X-ray diffraction and Scanning Electron Microscopy (SEM), shows that all of them crystallize in a NASICON-type structure with similar lattice parameters. Doping with Fe and Cr, causes an increase of the density of the samples after sinterization what clearly improves the ionic conductivity of the original material, LiTi{sub 2}(PO{sub 4}){sub 3} until values of 9x10{sup -}4 S cm{sup -}1 at room temperature in the chromium-doped material. (Author)

  7. Caracterització mineralògica dels materials dels dipòsits de tungstè de Mittersill i Morille per el seu processament

    OpenAIRE

    Call Espinalt, Joan

    2016-01-01

    La mineralogia dels dipòsits de tungstè de Mittersill (Àustria) i Morille (Espanya) han estat caracteritzats. L’objectiu d’aquest treball és caracteritzar dipòsits de tungstè per que es pugui desenvolupar una metodologia per tal d’assolir una millora substancial en l’alliberament del tungstè a partir de les menes estudiades. Per aconseguir-ho buscarem quina és la mida de màxim alliberament del mineral. La composició química ha estat obtinguda per mitjà d’una Espectrometria de Masses per Plasm...

  8. COMPOSIÇÃO QUÍMICA E AVALIAÇÃO DA ATIVIDADE CARRAPATICIDA DO ÓLEO ESSENCIAL DE Cinnamomun zeylanicum NO CONTROLE DE Rhipicephalus microplus

    OpenAIRE

    ILDENICE NOGUEIRA MONTEIRO

    2013-01-01

    Os constituintes do óleo de Cinnamomum zeylanicum foram identificados por cromatografia gasosa acoplada à espectrometria de massas (CG-EM). Também foi avaliada a atividade deste óleo essencial contra larvas e fêmeas de Rhipicephalus microplus (carrapato bovino). O óleo das folhas mostrou um rendimento de 1,03% e seus principais constituintes foram Benzoato de Benzila (65,39%), Linalol (5,37%), E-Cinamaldeido (3,97%), α-Pineno (3,95%), β-Felandreno (3,42%), Eugenol (3,36%) e Benzalde...

  9. Análises do proteoma de raízes de cana-de-açúcar e da expressão de uma peroxidase apoplástica responsiva à micorriza arbuscular

    OpenAIRE

    Simão Lindoso de Souza

    2006-01-01

    Micorrizas arbusculares (MAs) são associações simbióticas entre os fungos do filo Glomeromycota e a maioria das plantas. Os mecanismos moleculares que controlam o processo de colonização e desenvolvimento das MAs são ainda pouco conhecidos, mas proteínas com acúmulo diferencial em MAs podem ter papel regulatório importante. O presente trabalho teve como objetivo detectar, por meio de eletroforese bi-dimensional (2D-PAGE) e espectrometria de massas, proteínas com acúmulo diferencial no fluido ...

  10. Uso de marcadores fenotípicos e bioquímicos para caracterização de isolados de Aspergillus seção Flavi

    OpenAIRE

    Couto, F. A.; Santos, C.; Dias, E. S.; Lima, Nelson; Batista, L. R.

    2015-01-01

    Os fungos do gênero Aspergillus seção Flavi representam uma das seções mais importantes do gênero e apresentam elevada variabilidade morfológica e bioquímica. Com o advento da abordagem polifásica, sua taxonomia tem sido constantemente revisada. O presente trabalho teve como objetivo utilizar diferentes metodologias para verificar o poder discriminatório dos métodos morfológico, bioquímico, molecular e de espectrometria de massas de isolados de Aspergillus seção Flavi. Trinta e...

  11. DEVELOPMENT OF CAPILLARY ELECTROPHORESIS BASED METHODS WITH DIFFERENT DETECTION APPROACHES FOR DETERMINATION OF ORGANOTINS, STROBILURINS AND AMINOGLYCOSIDES

    OpenAIRE

    CABRINI FERRAZ DE SOUZA

    2013-01-01

    Neste trabalho, métodos baseados em diferentes abordagens em eletroforese capilar (CE) foram propostos. No caso da determinação de compostos organoestanhos ou OTs (difenilestanho e monofenilestanho) em fluidos biológicos, foi usada abordagem de eletroforese capilar por zona (CZE) hifenada com a espectrometria de massas (do tipo quadrupolo) com fonte de plasma indutivamente acoplado (CE-ICP-MS). As condições de análise foram estudadas no modo univariado visando otimizar a composição da solu...

  12. Análisis metalúrgico de la colección numismática

    OpenAIRE

    Montero Ruiz, Ignacio

    2009-01-01

    Durante los trabajos de excavación en la Mezquita de El Cristo de la Luz se recuperaron en diversos contextos y unidades estratigráficas alrededor de 300 monedas. Este conjunto de monedas es un reflejo de la propia historia del monumento y de la ciudad de Toledo, pero también con su estudio a través de técnicas de análisis elemental podemos profundizar en aspectos de Historia económica de mayor alcance.El análisis de composición se ha realizado a 77 monedas mediante espectrometria de fluoresc...

  13. DETERMINATION OF REFRACTORY ELEMENTS IN USED LUBRICATING OIL AND IN FUEL OIL BY ICP OES WITH EMULSIFIED SAMPLES

    OpenAIRE

    ROSELI MARTINS DE SOUZA

    2003-01-01

    O conhecimento da concentração dos elementos traço em óleo lubrificante usado é útil para a avaliação de desgastes de componentes específicos de motores.Em óleo combustível, este monitoramento permite avaliar a qualidade do combustível e prever o potencial das emissões de metais no meio ambiente. Neste trabalho, utilizou-se a espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) para a determinação de elementos refratários em amostras de ól...

  14. The Use of Research Reactors and Short-Lived Isotopes in the Study of Nuclear-Reactor Fuel Materials; Emploi de Reacteurs de Recherche et de Radioisotopes de Courte Periode dans l'Etude des Combustibles pour Reacteurs Nucleaires; ИСПОЛЬЗОВАНИЕ ИССЛЕДОВАТЕЛЬСКИХ РЕАКТОРОВ И КОРОТКОЖИВУЩИХ ИЗОТОПОВ ПРИ ИЗУЧЕНИИ ТОПЛИВНЫХ МАТЕРИАЛОВ ДЛЯ ЯДЕРННХ РЕАКТОРОВ; Empleo de Reactores de Investigacion y de Isotopos de Periodo Corto en el Estudio de Combustibles Nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Elleman, T. S.; Townley, C. W.; Sunderman, D. N. [Battelle Memorial Institute, Columbus, OH (United States)

    1963-03-15

    propiedades fisicas y quimicas de la muestra de combustible y de los productos de fision. Ademas, este procedimiento permite obtener datos, importantes para la ingenieria, sobre la radiactividad total liberada y la vida util del combustible. Las muestras se irradian generalmente en capsulas de doble pared que se sumergen en la piscina del reactor o en sus orificios experimentales y los productos de fision volatiles se extraen de la capsula con un gas de arrastre. Como la relacion existente entre la velocidad de desprendimiento y el periodo de semide- sintegracion del isotopo constituye un factor importante para determinar el mecanismo de desprendimiento, se recogen y analizan el cripton y el xenon, gases de fision con periodos de 1,7 s a 5,3 d. Los gases nobles de periodo corto (cripton-89, cripton-91, cripton-92, xenon-137, xenon-138, xenon-139, xenon-140 yxenon-141) se determinan recogiendo en un alambre cargado electricamente los productos de filiacion radiactivos no volatiles, que se determinan por analisis radioquimico, mientras que los gases de fision de periodo mas largo (cripton-85m, cripton-87, cripton-88, yodo-131, xenon-133 y xenon-135) se absorben en trampas refrigeradas de carbon activado ; por su parte, las fracciones yodo, cripton y xenon se separan por elucion en una columna cromatografica y se analizan por espectrometria gamma. Los productos de fision no volatiles liberados por la muestra se depositan en una trampa adyacente de lamina metalica, que se puede retirar en cualquier momento de la irradiacion para proceder a su analisis. La liberacion de productos de fision que se observa en diversas condiciones de irradiacion puede o no depender de la concentracion; con frecuencia se liberan selectivamente ciertos elementos, se produce un desprendimiento rapido de productos de fision durante los cambios de temperatura y despues del paro del reactor se liberan gases de fision. La tecnica descrita permite obtener datos fundamentales sobre el rendimiento de nuevos

  15. BIODISPONIBILIDADE DE METAIS TÓXICOS EM SEDIMENTOS DO RIO SUBAÉ, BAHIA, BRASIL

    Directory of Open Access Journals (Sweden)

    Jucelino Balbino da Silva Júnior

    2016-12-01

    Full Text Available Este trabalho avaliou a biodisponibilidade dos metais Pb, Cd, Zn, Cu e Ni, empregando a técnica dos sulfetos voláteis em ácido (AVS e metais simultaneamente extraídos (SEM, contemplando período chuvoso e de estiagem. As amostras de sedimento foram coletadas em 10 (dez estações ao longo da bacia do rio Subaé, desde a sua nascente até a foz na Baía de Todos os Santos (BTS. Os metais liberados durante a extração foram analisados usando espectrometria de fluorescência de raios-X (TXRF e espectrometria de absorção atômica com otimização eletrotérmica em forno de grafite (GFAAS, e os sulfetos voláteis foram quantificados utilizando potenciometria com eletrodo de íon seletivo (IES. A partir dos resultados obtidos, pode-se concluir, em função dos valores encontrados para os sulfetos e da matéria orgânica, que as concentrações de metais apresentaram valores que caracterizam a possibilidade de efeitos biológicos adversos para a biota nas regiões de baixa salinidade, em ambos os períodos.

  16. Colaboración con el responsable de riesgos laborales del centro en la gestión del sistema de prevención de riesgos de la Fundación CARTIF

    OpenAIRE

    Vicente Iglesias, Patricia

    2012-01-01

    En el presente trabajo se desarrollan las memorias de las prácticas de empresa propuestas por el Máster de Gestión de Prevención de Riesgos Laborales, Calidad y Medio Ambiente, realizadas en Fundación Cartif, durante un periodo de 180 horas, basadas en el área de prevención de riesgos laborales, en sus tres especialidades: seguridad, higiene y ergonomía. Ingenería de Quimica y Tecnología del Medio Ambiente Máster en Gestión de la Prevención de Riesgos Laborales, Calidad y Medio...

  17. Determination of elements in the atmosphere of Valle de Toluca by Neutron Activation (July 1992 - April 1993)

    International Nuclear Information System (INIS)

    Garcia S, I.

    1994-01-01

    The purpose of this study is to continue with the environmental monitoring program of Valle de Toluca by means of the Neutron Activation Analysis and atomic absorption techniques. The analytical results corresponding to the period of July 1992 to April 1993, and the analyzed elements by Neutron Activation were Na, V, Br, Al and Mn, while Cr and Pb were analyzed by Atomic Absorption Spectroscopy. Since the study is a joint project with the Facultad de Quimica de la Universidad Autonoma del Estado de Mexico, the purpose is to continue with this type of chemical analysis. (Author)

  18. Electrochemical noise measurements techniques and the reversing dc potential drop method applied to stress corrosion essays

    International Nuclear Information System (INIS)

    Aly, Omar Fernandes; Andrade, Arnaldo Paes de; MattarNeto, Miguel; Aoki, Idalina Vieira

    2002-01-01

    This paper aims to collect information and to discuss the electrochemical noise measurements and the reversing dc potential drop method, applied to stress corrosion essays that can be used to evaluate the nucleation and the increase of stress corrosion cracking in Alloy 600 and/or Alloy 182 specimens from Angra I Nuclear Power Plant. Therefore we will pretend to establish a standard procedure to essays to be realized on the new autoclave equipment on the Laboratorio de Eletroquimica e Corrosao do Departamento de Engenharia Quimica da Escola Politecnica da Universidade de Sao Paulo - Electrochemical and Corrosion Laboratory of the Chemical Engineering Department of Polytechnical School of Sao Paulo University, Brazil. (author)

  19. Ellipsometry and electronic microscopy of ashes swept of the Popocatepetl volcano; Elipsometria y microscopia electronica de barrido de las cenizas del volcan Popocatepetl

    Energy Technology Data Exchange (ETDEWEB)

    Munoz, Aaron; Munoz, Rafel; Falcon, Nelson [Universidad de Carabobo, Valencia (Venezuela); Chavira, Enrique [Instituto Nacional de Astrofisica Optica y Electronica, Puebla (Mexico)

    2001-12-01

    The ellipsometry and the scanning electronic microscopy is applied to the study of the optic properties of Popocatepetl volcano ash in connection with the form, ruggedness and elemental chemical composition of the microparticles, also to argue about the relation with atmospheric conditions. [Spanish] Se aplica la eliposometria y la microscopia electronica de barrido al estudio de las propiedades opticas de las cenizas de volcan Popocatepetl en relacion con la forma, rugosidad y composicion quimica elemental de las microparticulas, destacandose su vinculacion con las condiciones de visibilidad.

  20. Networks 90: Polymer Networks Group Meeting (10th) and IUPAC international Symposium on Polymer Networks (10th) Held in Jerusalem on 20-25 May 1990. Programme and Abstracts

    Science.gov (United States)

    1990-05-25

    Ingenieria Quimica, 12 de octubre 1842, 8000 Bahia Blanca, Argentina. P-36 BRANCHING KINETICS OF EPOXY POLYMERIZATION OF 1,4-BUTANEDIOL DIGLYCIDYL ETHER...OF ENTANGLED POLYMERS IN MELTS L-6 J. des Cloizeaux (France) 14:45-15:05 THE CONCEPT OF INTRINSIC CHAIN STRESS IN L-7 POLYMER NETWORKS J.J. Weiner, J...RELATION TO DIFFUSIVE TRANSPORT A.M. Weiss, K. Adler, A.J. Grodzinsky, M.L. Yarmush (Israel, USA) 15:05-15:25 DIFFUSION BEHAVIOUR IN SOLUTIONS OF L-25

  1. Eliminación de contaminantes emergentes mediante adsorción empleando xerogeles de carbón

    OpenAIRE

    Álvarez, Silvia; Ribeiro, Rui; Gomes, Helder; Sotelo, José; Garcia, Juan

    2014-01-01

    En la actualidad el número de sustancias quimicas potencialmente peligrosas que pueden lIegar a alcanzar el medio ambiente es muy amplio, por lo que la atención en la investigación de la contaminación dei agua se ha extendido recientemente a lo que se denomina contaminación emergente; es decir, la contaminación causada por sustancias químicas de origen y propiedades muy diversas, en concentraciones muy bajas, y que persisten en las aguas residuales tras el tratamiento de éstas ...

  2. Sorción de hidrolizados proteicos en lana tratada con bisulfito sódico: influencia en las propiedades químicas y físico-mecánicas.

    OpenAIRE

    Gómez de Paula, Ma Nieves; Naik Kardile, Arun; Juliá Ferrés, Ma. Rosa; Erra Serrabasa, Pilar

    1997-01-01

    La sorción de hidrolizados proteicos en fibras queratinicas provoca una mejora en las propiedades físicas y quimicas de fibras dañadas. En este trabajo se presentan los resultados de las modificaciones de estas propiedades en lana tratada con bisulfito sódico e hidrolizado proteico bien de colágeno o de queratina o de sus respectivos derivados anfifílicos cuaternizados y se comparan con las obtenidas para lana tratada sólo con bisulfito sódico. The sorption of protein hydrolisates in kerat...

  3. DANAE: simulador de propiedades fisicoquímicas como una combinación entre la racionalización más pura y profunda y la medición experimental más tactual y empirica

    Directory of Open Access Journals (Sweden)

    Daniel Bogoya Maldonado

    1991-03-01

    Full Text Available Este articulo pretende ilustrar una combinación entre la razón y la experiencia para estimar propiedades fisicoquímicas, útiles para el cálculo de balances de materia y energia, de uso frecuente en ingenleria quimica. Igualmente, presenta el sistema DANAE, desarrollado para calcular interactivamente por microcomputador seis propiedades de compuestos puros y cinco de mezclas (hasta de quince componentes, basado en un banco de datos (de tamaño 250 KB Y dos programas principales (de tamaño 80 KB.

  4. Thermoregulation: Research and Clinical Applications

    Science.gov (United States)

    1989-08-01

    NEDERGAARD The Wenner-Gren Institute, Biologihus F3, University of Stockholm, S-106 91 Stockholm (Sweden) and *Cdtedra de Bioquimica , Facultad de Quimica...heart rate and a lack of arrhythmias. This was true as the temperature dropped and reached a low of 30-32°C, as well as in the actual recovery peri...like this to establish whether the response is linear with added amount, and the actual absorbance observed on each plate is not only a function of

  5. A simple model to evaluate the impact of the thermal power plants emissions; Un modelo simple para evaluar el impacto de las emisiones de centrales termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Rodas Grapain, Arturo; Salcido, Alejandro [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2000-07-01

    Formulation and validation of a dispersion model for relative plumes are presented in this paper. This model (MOTTQUIP: Modelo de Transporte Turbulento y Quimico de Plumas) was developed to assess the environmental impact of power generation. The theoretical formulation if this model is based on the integral form of the mass balance equation. MOTTQUIP can simulate (in two dimensions) the turbulent dispersion and chemical transformation phenomena of a nitrogen oxides (Nox) non-buoyant plume in an ozone (O{sub 3}) atmosphere. The results produced by MOTTQUIP, however, can run in a personal computer consuming relatively short CPU times. [Spanish] En este trabajo se presentan la formulacion y la validacion de un modelo (MOTTQUIP: Modelo de Transporte Turbulento y Quimica de Plumas) para evaluar el impacto de las emisiones de contaminantes reactivos de centrales termoelectricas. Este modelo se formula a partir de la forma integral de la ecuacion de balance de masa, y no de su forma diferencial, como se procede generalmente. MOTTQUIP simula, en dos dimensiones, la dispersion turbulenta y transformacion quimica de una pluma no flotante de oxidos de nitrogeno (Nox), misma que se interna paulatinamente en un ambiente de ozono (O{sub 3}). Los resultados obtenidos son comparados con los de modelos alternos que simulan el mismo sistema reactivo, encontrandose una concordancia bastante aceptable. Una ventaja de MOTTQUIP, sin embargo, es que puede utilizarse en sistemas de computo pequenos, empleando tiempos de CPU relativamente cortos.

  6. Síntese e caracterização de um novo composto obtido pela reação entre hidreto de trifenilestanho e ácido (±)-mandélico e avaliação de seu potencial biocida sobre o fungo Fusarium oxysporum f. sp. cubense

    OpenAIRE

    Barbiéri, Roberto Santos; Lima, Elysio Prado de; Silva, Samuel Ferreira da; Dias, Allan Kardec Carlos; Cardoso, Maria das Graças; Terra, Vilma Reis

    2006-01-01

    O presente artigo refere-se à síntese e caracterização de um novo composto organoestânico, pela reação de ácido (±)-mandélico e hidreto de trifenilestanho, em meio de acetonitrila e sob refluxo, [(C6H5)2SnMand 2] {Mand = C6H5CH(OH)COO], identificado por análise elementar de carbono e hidrogênio, espectroscopia no infravermelho e espectrometria de massa de alta resolução, para o qual foi proposta estrutura octaédrica com o grupo fenila em posição trans. Verificou-se que o composto apresenta aç...

  7. Síntese e caracterização de um novo composto obtido pela reação entre hidreto de trifenilestanho e ácido (±)-mandélico e avaliação de seu potencial biocida sobre o fungo Fusarium oxysporum f. sp. cubense Synthesis, characterization and evaluation of the biocide effect on the fungus Fusarium oxysporum f. sp. cubense of a new compound obtained by reaction of triphenyltin hydride and (±)-mandelic acid

    OpenAIRE

    Roberto Santos Barbiéri; Elysio Prado de Lima; Samuel Ferreira da Silva; Allan Kardec Carlos Dias; Maria das Graças Cardoso; Vilma Reis Terra

    2006-01-01

    O presente artigo refere-se à síntese e caracterização de um novo composto organoestânico, pela reação de ácido (±)-mandélico e hidreto de trifenilestanho, em meio de acetonitrila e sob refluxo, [(C6H5)2SnMand 2] {Mand = C6H5CH(OH)COO], identificado por análise elementar de carbono e hidrogênio, espectroscopia no infravermelho e espectrometria de massa de alta resolução, para o qual foi proposta estrutura octaédrica com o grupo fenila em posição trans. Verificou-se que o composto apresenta aç...

  8. Development and validation of methodology SPE-LC-MS/MS for pharmaceuticals and illicit drug determination in the waters of Guarapiranga dam - Sao Paulo/SP, Brazil

    OpenAIRE

    SHIHOMATSU, HELENA M.

    2015-01-01

    Este estudo apresenta o desenvolvimento da metodologia de extração em fase sólida e separação em cromatográfica líquida acoplada a espectrometria de massas em sequencia, SPE-LC-MS/MS, para a determinação de 21 (vinte e um) fármacos pertencentes a diferentes classes terapeuticas, 1 (uma) droga de abuso e seu principal metabólito, em amostras de água superficial. A separação cromatográfica foi otimizada estudando o desempenho de fases estacionárias e fases móvies. A quantificação dos compostos ...

  9. Utilização da espectroscopia Raman na identificação de drogas ilícitas em perícia criminal

    OpenAIRE

    Silveira, Gustavo de Carvalho

    2013-01-01

    Este trabalho é um resumo do dia a dia dos laboratórios de perícia. As principais drogas apreendidas são descritas como a maconha, cocaína, crack, ecstasy, dentre outras. Comenta a legislação brasileira aplicada tanto no consumo e tráfico de entorpecentes quanto na classificação dessas substâncias proibidas. Cita também os métodos convencionais de análise como cromatografia em camada delgada e os colorimétricos e os métodos oficiais nos quais ocorrem o acoplamento da espectrometria de massas ...

  10. Essential oil from two populations of Echinodorus grandiflorus (Cham. & Schltdl. Micheli (Chapéu de couro

    Directory of Open Access Journals (Sweden)

    Daniel S. Pimenta

    2006-12-01

    Full Text Available Analysis by Gas Chromatography and Gas Chromatography/Mass Spectrometry of the essential oils obtained from leaves of Echinodorus grandiflorus ("Chapéu de couro" from two different populations (Big Leaves and Small Leaves, collected monthly between September 1998 and December 1999 revealed 17 components. Phytol was the major constituent for both populations. The main sesquiterpene representatives are (E-caryophyllene, alpha-humulene and (E-nerolidol.Análise por cromatografia com fase gasosa e cromatografia com fase gasosa acoplada à espectrometria de massas de óleos essenciais obtidos de folhas de Echinodorus grandiflorus ("Chapéu-de-couro" em duas diferentes populações (folhas grandes e folhas pequenas, coletadas mensalmente entre setembro de 1998 e dezembro de 1999, revelou 17 componentes. Fitol foi o constituinte majoritário em ambas populações. Os principais representantes sesquiterpênicos foram (E-cariofileno, alfa-humuleno e (E-nerolidol.

  11. Goiaba (psidium guajava L.) cultivar IAC-4 : carotenoides e outras propriedades, mudanças durante processamento e estocagem

    OpenAIRE

    Marisa Padula

    1983-01-01

    Resumo: Através da cromatografia em coluna e em camada delgada, espectrometria de absorção visível e reações químicas, os carotenóides na goiaba Cultivar IAC-4 foram identificados como: 8-caroteno, ζ-caroteno, γ-caroteno, zeinoxantina, licopeno, 5,6,5',6'- diepóxi-B-caroteno e 5,8-epóxi-3,31,4-trihidroxi-3-caroteno. O principal pigmento foi o licopeno, correspondendo a 86% de 62 γg/g de carotenóides totais. O teor de B-caroteno foi 3,7 γg/g, conse- qüentemente o valor de v...

  12. Conversão do metanol em olefinas catalisada por zeólitas com diferentes características ácidas e estruturais

    OpenAIRE

    Flávia Figueiredo Almaraz

    2011-01-01

    A reação de transformação de metanol em olefinas leves foi investigada sobre as peneiras moleculares HZSM-5, HFER, SAPO-34 e HMCM-22. A caracterização físico-química das amostras foi realizada através das técnicas de FRX, DRX, fisissorção de nitrogênio, MEV, espectrometria no IV com adsorção de piridina e TPD de NH3. O desempenho catalítico das mesmas foi comparado em condições de isoconversão inicial de 755%. Verificou-se que as características ácidas e estruturais exerceram forte influência...

  13. Efeitos deleterios dos cloretos em reservatorios de concreto

    OpenAIRE

    Matoski, Adalberto

    1998-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnologico Caracterização dos reservatórios de água potável das regiões de Curitiba e Florianópolis, quanto às patologias apresentadas. Utilização do ensaio de potencial de eletrodo para a definição das linhas equipotenciais sobre a laje de concreto dos reservatórios. Análise dos efeitos do cloro adicionado à água, para sua desinfecção, sobre o concreto. Comparaçao entre os ensaios químico e de espectrometria de raio...

  14. Um método espectrométrico de emissão em chama baseado em imagens digitais para determinação indireta de fármacos e determinação simultânea de sódio e cálcio

    OpenAIRE

    Lyra, Wellington da Silva

    2012-01-01

    Neste trabalho a potencialidade da Espectrometria de Emissão em Chama Baseada em Imagens digitais (DIB-FES) é demonstrada por meio de duas aplicações completamente distintas. A primeira consiste na determinação indireta de três fármacos em soluções injetáveis: diclofenaco sódico, dipirona sódica e gluconato de cálcio e a segunda na combinação da DIB-FES com Regressão Linear Múltipla (MLR) para a determinação simultânea de sódio e cálcio em amostras de leite em pó. Até o pres...

  15. MÉTODO MULTIRRESÍDUO PARA DETERMINAÇÃO DE MICOTOXINAS EM VINHO POR UPLC-MS/MS

    OpenAIRE

    Laís Weber Righi

    2013-01-01

    Um método rápido usando cromatografia líquida de ultra eficiência acoplada a espectrometria de massas (UPLC-MS/MS) foi implementado e otimizado para proporcionar a determinação completa de 36 micotoxinas em amostras de vinhos. A extração foi realizada com acetonitrila, aplicando o método QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe; em português: Rápido, Fácil, Barato, Efetivo, Robusto e Seguro) modificado. Tradicionalmente, o método QuEChERS é muito conhecido na determinação de múlt...

  16. Perspectivas mecanisticas de reações organicas catalisadas por paladio : Heck, oxa-Heck e acoplamento de Buchwald-Hartwig por ESI-MS/MS

    OpenAIRE

    Boniek Gontijo Vaz

    2009-01-01

    Resumo: A espectrometria de Massas por eletronspray (ESI-MS) tornou-se um método prático para o estudo de mecanismos reacionais em solução. Neste trabalho importantes reações catalisadas por paládio: reação de Heck-Mizoroki, oxa-Heck e o acoplamento de Buchwald-Hartwig foram monitoradas por ESI-MS visando interceptar espécies que comprovam as atuais propostas mecanísticas ou que abram caminho para novas propostas para estas reações. O monitoramento das reações foi realizado no modo off-line, ...

  17. Determinação Simultânea de Metais em Cachaças Utilizando Voltametria de Redissolução Com Eletrodos de Nanotubo de Carbono e Calibração Multivariada.

    OpenAIRE

    FERREIRA, R. J.

    2015-01-01

    Cachaças são destilados provenientes de cana de açúcar, gerando teores alcoólicos em faixas de porcentagem de 38% a 48% em volume. Devido a seu grande consumo no país e sua complexidade em constituição química, promoveu-se neste trabalho a determinação dos metais cobre, zinco, cadmio e chumbo, que em quantidades elevadas, são nocivos à saúde e ao metabolismo humano. Determinou-se as concentrações desses metais por meio da espectrometria de emissão óptica com plasma indutivamente acoplado (ICP...

  18. New group of oligosaccharides excreted in honeydew from scale insects Stigmacoccus sp. And coccus hesperidium L. Novo grupo de oligossacarídeos excretado no "honeydew" das cochonilhas Stigmacoccus sp. e coccus hesperidum L.

    Directory of Open Access Journals (Sweden)

    Amauri Bogo

    2003-08-01

    Full Text Available Analysis of the honeydew from scale insects Stigmacoccus sp. and Coccus hesperidium (L. were carried out by paper chromatography, FAB-MS and GC-MS. The results showed three components (tri-, tetra- and penta-saccharides which were composed by 1,4 glucose(s linked to the glucose of sucrose. The findings therefore imply significant and novel metabolic transformations of sugars by the insect and/or microbial symbionts. From these results, structures and common names as "Stigmatriose, Stigmatetraose and Stigmapentose" were proposed for these oligosaccharides because they were found initially in Stigmacoccus sp. honeydew.Análise da secreção doce ou açucarada produzida pelas cochonilhas Stigmacoccus sp. e Coccus hesperidium (L. foi realizada pelas técnicas de cromatografia de papel, bombardeamento de átomo rápido-espectrometria de massas (FAB-MS e cromatografia gasosa-espectrometria de massas (GC-MS. Os resultados mostraram a presença de três oligossacarídeos (tri-, tetra- e pentassacarídeos os quais são compostos por uma ou mais moléculas de 1,4-glucopiranose ligadas à posição 1-glucopiranose do dissacarídeo sacarose. A constatação da presença destes oligossacarídeos na secreção doce ou açucarada das espécies citadas sugere um significante e novo metabolismo de transformação de açucares pelo inseto e/ou por simbiontes microbianos. A partir destes resultados, e por não existirem referências sobre o assunto, sugerem-se as fórmulas estruturais e os nomes comuns de "Estigmatriose, Estigmatetraose e Estigmapentaose" pelo fato de terem sido inicialmente encotrados no honeydew de Stigmacoccus sp.

  19. ANÁLISE DE METAIS EM AMOSTRAS COMERCIAIS DE ERVA-MATE DO SUL DO BRASIL

    Directory of Open Access Journals (Sweden)

    Ana Paula SAIDELLES

    2010-11-01

    Full Text Available

    A erva-mate (Ilex paraguariensis, St. Hill. ingerida como infusão a quente, chamada de “chimarrão”, é uma cultura com grande valor comercial para os estados do sul do Brasil. Atualmente muitos estudos tem sido desenvolvidos buscando estabelecer os benefícios terapêuticos e efeitos colaterais à saúde humana da erva-mate, que podem estar relacionados à presença de metais. Neste trabalho foram determinadas as concentrações de metais essenciais e tóxicos na composição da erva-mate comercializada e consumida nos diferentes estados do sul do Brasil. Amostras provenientes do Rio Grande do Sul, Paraná e Santa Catarina foram analisadas para a determinação da concentração de Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Na, Ni, Pb, Sr, V, Zn por espectrometria de massa com plasma indutivamente acoplado (ICP-MS e espectrometria de emissão óptica com plasma indutivamente acoplado (ICP-OES. Observou-se que a concentração média de todos os metais analisados nas amostras estava dentro dos limites toleráveis. Entretanto, foram observadas concentrações minerais diferenciadas entre as regiões estudadas. Desta forma, a erva-mate pode ser recomendada na utilização diária, podendo suprir necessidades básicas de ingestão desses metais essenciais sem o risco de problemas causados por elementos tóxicos.

  20. Environmental radiation monitoring in Sao Paulo state

    International Nuclear Information System (INIS)

    Agudo, E.G.; Albuquerque, A.M. de; Vasconcellos, N.V. de

    1991-01-01

    The results of environmental radiation monitoring that CETESB (Technological Company of Environmental Sanitation of Sao Paulo) does in influence areas of radioactive materials store of Nuclemon Minero-Quimica S.A. in the municipality of Itu, Sao Paulo State, are presented. The data comprises the period of 1983-1990 with information about concentration levels of radium-225 in underground and superficial waters of the region. On March, 1989, was detected contamination in a well near of the stores. The levels observed, its implications in terms of health risks and possible causes of event are discussed too. The goals that CETESB intends to reach in terms of monitoring of environmental radiation in Sao Paulo State are also presented. (C.M.)