Sample records for digestao quimica espectrometria
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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
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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.
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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...
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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.
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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
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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
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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 ...
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Espectrometria de massas avançada em estudos estruturais de metabólitos de fármacos e proteínas
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 ...
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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
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Removal of Perchlorate from Water and Wastewater by Catalytic Hydrogen Gas Membrane Systems
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
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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
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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...
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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.
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Constraints on the Grueneisen Theory
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
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A Note on the Application of the Extended Bernoulli Equation
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
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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
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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
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The Conference on the Dynamics of Molecular Collisions Held at Snowbird, Utah on 14-19 July 1985.
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
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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
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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...
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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)
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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...
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Source Hierarchy List. Volume 1. A through D
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
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Synthesis of Chromophores for Nonlinear Optics Applications
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
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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
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Cholesteric Liquid Crystal Glass Platinum Acetylides
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
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New Meta and Nanomaterials for Photorefractive Enhancement and Photorefractive Two-Beam Coupling
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
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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
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Mechanisms of Laser Induced Reactions in Opaque Heterogeneous Environments
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
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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
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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
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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 ...
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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
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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...
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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.
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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 ...
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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...
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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
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Development of New Photorefractive Polymer Materials
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
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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
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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
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Area Handbook Series: Portugal, A Country Study
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
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Meeting on Solute/Solvent Interactions Held in Aberdeen Proving Ground, Maryland on May 29-30, 1991
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
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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
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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.
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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%.
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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...
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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
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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.
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Atomic Energy Levels. As Derived From the Analyses of Optical Spectra. Volume 3
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
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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.
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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 ...
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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.
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Characterisation of gas and particle emissions from wildfires =
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
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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 ...
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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.
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A Simple DWBA (’Franck-Condon’) Treatment of H-Atom Transfers between Two Heavy Particles.
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
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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
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Interfacial Effects and Organization of Inorganic-Organic Composite Solids.
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
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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...
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Theoretical Crystal-Field Calculations for Rare-Earth Ions in III-V semiconductor Compounds
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
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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.
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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 ...
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Materials for Energy Conversion and Environmental Protection
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
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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 ...
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Localization and Specification of Copper Ions in Biofilms on Corroding Copper Surfaces.
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
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Binding of Pentaammineruthenium(II) Residues to the Tris(bipyrazine)ruthenium(II) Cation.
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
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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 )
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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
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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
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Soldier-Portable Battery Supply: Foreign Dependence and Policy Options
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
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(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 ...
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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
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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 ...
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International Symposium on Gas Kinetics (9th) Held in Bordeaux, France on 20-25 July 1986. Abstracts
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
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Molecular Recognition in the Oxidation of Catechols by Dicobalt-BISDIEN Dioxygen Complexes
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
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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
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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
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Dynamics of Electron Transfer for a Nonsuperexchange Coherent Mechanism. I
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
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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 ...
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Source Hierarchy List. Volume 3. O through Z
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
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JPRS Report, Proliferation Issues
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
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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.
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Thin Metallic Films from Solvated Metal Atoms.
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
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Planetary Conjunction: Economics, Politics, and Partnering In Space
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
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Estudio de arcillas peruanas por espectrometria mossbauer
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...
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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
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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
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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
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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
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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...
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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:) ON THE ASSIGNMENT
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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
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Symposium Q: Magnetic Thin Films, Heterostructures, and Device Materials
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
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Lipopolysaccharide Antigens of Pseudomonas aeruginosa and Design of Novel Vaccines.
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
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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
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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
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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.
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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...
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20th International Conference on Solid State Ionics (SSI 20)
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
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European Science Notes Information Bulletin Reports on Current European/ Middle Eastern Science
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
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Microbiologically Influenced Corrosion in Copper and Nickel Seawater Piping Systems
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
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Brazil, the United States, and the Missile Technology Control Regime
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
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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.
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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)
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GPU-Accelerated Optical Coherence Tomography Signal Processing and Visualization
Darbrazi, Seyed Hamid Hosseiny
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Oliveira, Marta Madalena Marques de
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Viscoelastic nanocapsules under flow in microdevices
Cordeiro, Ana Lucinda Teixeira
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Clinopyroxene based glasses and glass-ceramics for functional applications
Goel, Ashutosh
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Rodrigues, Arlete da Silva
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Single Point Incremental Forming and Multi-Stage Incremental Forming on Aluminium Alloy 1050
Suriyaprakan, Premika
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Albumin and fibronectin adsorption and osteoblast adhesion on titanium oxides
Freitas, Susana Maria Ribeiro e. Sousa Mendes de
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Stellar activity in high-precision photometric and spectroscopic transit observations
Oshagh, Mahmoudreza
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Laranjeira, Marta de Sousa
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Impact evaluation of the large scale integration of electric vehicles in the security of supply
Bremermann, Leonardo Elizeire
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Starch and polyethylene based bone-analogue composite biomaterials
Reis, Rui Luis Goncalves dos
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Magnetism at the nanoscale: Nanoparticles, nanowires, nanotubes and their ordered arrays
Proenca, Mariana Jesus Paiva
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Birefringence and Bragg grating control in femtosecond laser written optical circuits
Fernandes, Luis A.
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Improving the characteristics of foundry alloys AlSiCuMg during manufacturing
Fragoso, Bruno Filipe Marques
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Seismic assessment of reinforced concrete frame structures with a new flexibility based element
Arede, Antonio Jose Coelho Dias
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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Couto, Diana Manuel Mocho de Bastos
As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de
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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 ...
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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...
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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...
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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.
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2-[3-Furyl(hydroxy)methyl]-2,3-dimethylcyclohexanone.
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].
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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
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Thermoregulation: Research and Clinical Applications
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
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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.
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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.
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Utilização da espectroscopia Raman na identificação de drogas ilícitas em perícia criminal
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 ...
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Análisis metalúrgico de la colección numismática
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...
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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...
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MÉTODO MULTIRRESÍDUO PARA DETERMINAÇÃO DE MICOTOXINAS EM VINHO POR UPLC-MS/MS
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...
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Efeitos deleterios dos cloretos em reservatorios de concreto
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...
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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, ...
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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...
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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)
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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.
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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.
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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...
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Eliminación de contaminantes emergentes mediante adsorción empleando xerogeles de carbón
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 ...
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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.
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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...
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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...
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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 ...
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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...
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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...
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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
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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.
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Bortoluzzi, Janaína Heberle
2007-01-01
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Físicas e Matemáticas. Programa de Pós-Graduação em Quimica. Neste trabalho a técnica de SPME aliada a GC-MS foi aplicada para o estudo da degradação térmica do poli(propileno) e do poli(estireno)-co-poli(metil metacrilato). São discutidos principalmente os produtos formados, mecanismos de formação dos principais produtos e parâmetros cinéticos de degradação. Degradaram-se os polímeros num forno tubular em divers...
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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...
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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)
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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...
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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)
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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
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Freitas, Carolina Gomes; Walsh, Michael; Atallah, Álvaro Nagib
2017-06-07
Warfarin is a commonly used anticoagulant. Whether a given dose of the different formulations of Brazilian warfarin will result in the same effect on the international normalized ratio (INR) is uncertain. The aim of the WARFA trial is to determine whether the branded and two generic warfarins available in Brazil differ in their effect on the INR. WARFA is a cross-over RCT comparing three warfarins. The formulations tested are the branded Marevan® (Uniao Quimica/Farmoquimica) and two generic warfarin (manufactured respectively by Uniao Quimica Farmaceutica Nacional and Laboratorio Teuto Brasileiro). All of them were manufactured in Brazil, are available in all settings of the Brazilian healthcare system and were purchased from retail drugstores. Eligible participants had atrial fibrillation or flutter, had been using warfarin for at least 2 months with a therapeutic range of 2.0-3.0 and had low variability in INR results during the 1st period of the trial. Our primary outcome, for which we have an equality hypothesis, is the difference between warfarins in the mean absolute difference between two INR results, obtained after three and 4 weeks with each drug. Our secondary outcomes, that will be tested for inequality (except for the mean INR, which will be tested for equality), include the difference in the warfarin dose, and time in therapeutic range. Clinical events and adherence were also recorded and will be reported. To our knowledge, WARFA will be the first comparison of the more readily applicable INR results between branded and generic warfarins in Brazil. WARFA is important because warfarins are commonly switched between in the course of a chronic treatment in Brazil. Final results of WARFA are expected in May 2017. ClinicalTrials.gov NCT02017197 . Registered 11 December 2013.
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International Nuclear Information System (INIS)
Cartin Elizondo, Jorge Eduardo
2014-01-01
Chemical analysis of polar pesticides has been qualitatively interest in forensic scientific research by toxicological qualities to the attainment of crimes against human life, pets and plants; associating people and objects in the scene and the possible ways in which the events occurred. The Unidad de Toxicos y Varios of the Seccion de Quimica Analitica of the Departamento de Ciencias Forenses has analyzed polar pesticides and other families to concentration levels, is compared to the environmental analysis and quality control of food. The compounds are used in Costa Rica in recent years as acute chemical weapon to commit crimes against human and animal life. The toxic and lethal amounts of polar pesticides in mammals orally have been milligram level. The Seccion de Quimica Analitica has developed a qualitative methodology to analyze polar pesticides as minor components. The need for reliable analytical quality results has made it necessary to approach a review of the methodology of routine. The review has been solved by selecting two matrices characteristics in such cases: a solid food commercially known as maria biscuits and a carbonated cola. Analytes have been selected based on: greater toxicity, broad spectrum of analytes polarity, the octanol-water partition constant, the water solubility among others. The extraction of analytes in matrices has been selected by solid-phase extraction. The instrumental technique used is gas chromatography with mass selective detector. A method of acquisition optimized in its injection is used. The analysis of instrumental signals were obtained in scanning mode all ions formed, known as Scan and by monitoring mode of ions selected ions (MIS), analysis of the data is acquired in Scan mode because concentration levels of work. The methodology for the qualitative determination of pesticide meets the criteria established for the chemical identification of analytes carbofuran, phorate, terbufos, methyl parathion, chlorpyrifos and
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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.)
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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
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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.
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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).
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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
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International Nuclear Information System (INIS)
Mozeto, A.A.; Fontanetti, A.R.
1986-01-01
The working conditions of a system for low-level tritium analyses in natural waters were determined using eletrolytic enrichment and liquid scintillation counting techniques. The system installed at the Departamento de Quimica - UFScar is characterized by the following experimental parameters: (a) sample volume reduction factor during eletrolysis = 16.7; (b) tritium recovery factor = 80%; (c) tritium enrichment factor = 13.4; (d) counting efficiency = 12.5%; (e) background level = 11.5 cpm; (f) counting time per sample = 500 minutes; (g) sensitivity = 8.3 TU/cpm; (h) lower detection limit = 3.6 TU + - 50% and (i) analytical capacity = 30 samples/month. It is also discussed the suitability of the analytical system in terms of rain and ground water samples as well. (Author) [pt
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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
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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
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Implantação de um sistema de gestão de reagentes em laboratórios universitários
Directory of Open Access Journals (Sweden)
Nelio Garbellini de Carvalho
2010-12-01
Full Text Available Los temas ambientales han sido cada vez más discutidos actualmente y nuevas praticas en ese sentido están ganando importancia en diversos sectores, por ejemplo, en las instituciones de enseñanza superior. En esa obra fueron diagnosticadas y analisadas, a través de un cuestionário aplicado a los encargados, las atividades relacionadas al manejo de los reactivos y el medio como su control es ejecutado por los laboratorios del Departamiento de Quimica de la Universidad Federal de Sao Carlos. De esa manera, fue desarrollado un software integrado entre los laboratorios, para la gestión de los reactivos, buscando disminuir el desperdício de ellos y la compra desnecesaria, lo que ayuda a minimizar la generación de residuos y el impacto ambiental.
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Directory of Open Access Journals (Sweden)
Luiz Erlon Araújo Rodrigues
1990-06-01
Full Text Available Os processos inflamatórios que se desenvolvem durante as etapas avançadas da esquistossomose mansônica hepática foram relacionados, com o acúmulo de siderossomos, a capacidade dos íons ferrosos/férricos de desencadearem a formação de radicais livres e aperoxidação de lipídios membranáceos, assim como à diminuição da estabilidade das membranas dos diversos componentes do compartimento lisossômico hepático. Os lisossomos isolados de figados de camundongos infectados por 100 cercárias, com 80 e 100 dias de infecção, foram respectivamente, 2,5 e quase 4 vezes mais frágeis que os controles, isolados de figados de camundongos não infectados. A presença de siderossomos em grande quantidade foi demonstrada por espectrometria aos raios-X.
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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.
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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)
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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.
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Efeito do pH sobre as caracteristicas fisico-quimicas do cream cheese.
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...
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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.
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SÍNTESE DO 2-ALIL-4-CLORO-6-ISOPROPIL-3-METILFENOL A PARTIR DO TIMOL
Directory of Open Access Journals (Sweden)
Ana Flávia Nunes de Paula Azevedo
2017-01-01
Full Text Available A industria agroquímica busca apresentar compostos cada vez mais eficientes, seletivos e seguros sob a perspectiva ambiental. Nesse contexto, a síntese de novos compostos ativos partindo de materia-prima natural apresenta-se como forte alternativa. Os sistemas catalíticos, que utilizam condições suaves de temperatura e pressão e apresentam grande rendimento mostram-se extremamente eficientes e tem conquistado seu espaço nas pesquisas agroquimicas, bem como a sintese de clorofenois usando ions cloreto como fonte de cloro e um oxidante adequado. O presente trabalho propos sintetizar um composto inédito análogo ao herbicida dicamba, partindo do timol, um fenol de origem natural. Seguindo uma rota de sintese em tres etapas, que teve rendimento global de 84% pode-se desenvolver o composto 2-alil-4-cloro-6-isopropil-3-metilfenol, que foi caracterizado por espectrometria de massas e infravermelho.
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Identificação de δ tocotrienol e de ácidos graxos no óleo fixo de urucum (Bixa orellana Linné
Directory of Open Access Journals (Sweden)
C.K. Costa
2013-01-01
Full Text Available Bixa orellana é uma planta nativa do Brasil, conhecida popularmente como urucum. O objetivo desse estudo foi extrair o óleo das sementes de B. orellana e, a partir dele, isolar e identificar o tocotrienol e quantificar seus ácidos graxos. A extração do óleo realizou-se em aparelho Soxhlet utilizando hexano como solvente extrator. O tocotrienol foi isolado por meio de métodos cromatográficos e identificado por espectrometria de ressonância magnética nuclear RMN ¹H e RMN 13C. Os ácidos graxos foram quantificados por cromatografia gasosa acoplada ao espectrômetro de massa. Os resultados demonstraram a presença de δ -tocotrienol e, dentre os ácidos graxos, a ocorrência do ácido aracdônico, que até o presente momento não havia sido relatada na espécie em estudo.
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Directory of Open Access Journals (Sweden)
Miriam Cristina Leone Potzernheim
Full Text Available Foi determinada a composição química dos óleos essenciais de 3 espécies do gênero Piper coletadas em Matas de Galeria no Cerrado, e comparada com composição dos óleos das mesmas espécies oriundas da Mata Atlântica. A composição química do óleo de Piper arboreum subsp arboreum, P. dilatatum e P. hispidum foi determinada por cromatografia gasosa em coluna capilar HP-5 e espectrometria de massas. As três espécies do Cerrado apresentaram predominância de sesquiterpenos. Piper arboreum subsp arboreum apresentou como constituintes majoritários biciclogermacreno (12,1%, 10-epi-g-eudesmol (11,6% e óxido de cariofileno (10,1%. Em P. dilatatum os constituintes em maior quantidade foram cis-b-ocimeno (19,6% e b-cariofileno (11,3% e em P. hispidum foram b-pineno (19,7%, a-pineno (9,0%.
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Desenvolvimento de surfatantes para aplicação na indústria de explosivos
Directory of Open Access Journals (Sweden)
Luciana Rodrigues Barreto Lopes
2014-08-01
Full Text Available A comercialização dos explosivos emulsionáveis, aí incluída a dinamite de ANFO, acarretou um aumento significativo no consumo mundial de explosivos entre 1960 e 1980, conseqüência da maior segurança no transporte e no preparo dos explosivos na forma de uma emulsão. Os surfatantes utilizados nestas emulsões são ésteres, amidas ou imidas derivadas do poliisobutileno com terminações de anidrido succínico (PIBSA. Neste trabalho, surfatantes derivados da reação do PIBSA com polioxietilenodiaminas foram sintetizados e caracterizados pelas técnicas de espectrometria no infravermelho e de cromatografia de exclusão de tamanho. Os surfatantes sintetizados foram avaliados quanto ao efeito das suas estruturas na redução da tensão interfacial do sistema água em óleo e todos foram capazes de reduzir a tensão interfacial deste sistema.
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Pirólise de resíduos poliméricos gerados por atividades offshore Pyrolysis of offshore solid wastes
Directory of Open Access Journals (Sweden)
Mara L. de Oliveira
2009-01-01
Full Text Available Resíduos plásticos gerados pelas atividades offshore da indústria de exploração e produção de óleo e gás, após caracterização por ensaio de identificação das classes poliméricas e análise térmica, foram pirolisados em atmosfera inerte a 450 °C. Os óleos pirolíticos foram caracterizados por espectrofotometria de infravermelho por transformada de Fourier (FTIR e cromatografia em fase gasosa acoplada à espectrometria de massas (CG/EM, indicando a composição de parafinas, olefinas e aromáticos.Solid wastes from oil and gas offshore exploration and production activities, after characterization of polymeric classes and thermal identification analysis tests, were pyrolysed under an inert atmosphere at 450 °C. The pyrolysis oil was characterized by Fourier Transform Infrared Spectroscopy (FTIR gas chromatography mass spectrometry (CG/EM, indicating high generation of paraffin, olefines and aromatics.
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Directory of Open Access Journals (Sweden)
T. Pinotti
2006-12-01
Full Text Available The ability of Geotrichum candidum to produce fruity aroma in food grade sucrose, molasses, corn steep liquor and peptone based culture media was tested by sensory evaluation and analyzed by gas chromatography mass spectrometry. A strong and sweet fruity aroma was produced from molasses, with peptone or corn steep liquor stimulating aroma production. Molasses with peptone supplemented with leucine, valine, or alanine yielded better fruity aroma production and the presence of many esters was consistent with the fruity aroma production.Geotrichum candidum foi cultivado em diversos meios de cultura contendo sacarose ou melaço e milhocina ou peptona e a produção de aroma frutal foi verificada através de avaliação sensorial e cromatografia gasosa acoplada a espectrometria de massas. Os meios contendo melaço, peptona e leucina, valina ou alanina apresentaram os melhores resultados e a presença de diversos ésteres foi consistente com a formação de aroma frutal.
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Constituintes químicos voláteis e não-voláteis de Moringa oleifera Lam., Moringaceae
Directory of Open Access Journals (Sweden)
Milena B. Barreto
Full Text Available O estudo fitoquímico do extrato etanólico das folhas de Moringa oleifera Lam., Moringaceae, resultou no isolamento dos derivados benzilnitrilas niazirina, niazirinina e 4-hidroxifenil-acetonitrila, enquanto que das cascas dos frutos somente o octacosano foi obtido. Os óleos essenciais das folhas, flores e frutos foram analisados por cromatografia gasosa acoplada a espectrometria de massa. Os constituintes principais identificados foram: fitol (21,6% e timol (9,6% nas folhas, octadecano (27,4% e ácido hexadecanóico (18,4% nas flores e docosano (32,7% e tetracosano (24,0% nos frutos. As estruturas dos compostos isolados foram identificadas a partir de técnicas espectroscópicas (RMN, IV e EM. A 4-hidroxifenil-acetonitrila está sendo citada pela primeira vez para o gênero Moringa e os óleos essenciais das flores e frutos estão sendo citados pela primeira vez para a espécie M. oleifera.
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Energy Technology Data Exchange (ETDEWEB)
1990-12-31
The objective of the Department of Applied Research is to carry out research on fields of physics, materials sciences, chemistry and engineering. Some branches of research can be mentioned: high Tc superconductors, hydrogen storage in metallic hydrides, extractive metallurgy of strategic minerals and others. In the first case, both the Development Division and the Thermodynamics group in the Metallurgy Division, have actively participated. [Espanol] El Dpto. de Investigacion Aplicada tiene como objetivo realizar investigacion en campos de la fisica, ciencias de materiales, quimica e ingenieria. Se pueden citar nuevas lineas de trabajo, entre ellos: los superconductores ceramicos de alta temperatura critica, el almacenamiento de hidrogeno en hidruros metalicos, el desarrollo de una servo-cuna computarizada, la metalurgia extractiva de materiales estrategicos y otros. En el primer caso han participado activamente la Div. Desarrollo y el Grupo de Termodinamica de la Division Metalurgia.
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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)
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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
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Energy Technology Data Exchange (ETDEWEB)
Tello Hinojosa, Enrique [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)
1996-01-01
Chemical analysis of water produced by 12 hot springs in the geothermal areas of Recubichi and Piedras de Lumbre, Chihuahua, Mexico were carried out in order to establish the geochemical characteristic of the groundwater and to know their interaction with deeper geothermal fluids. We made two sampling of water and gases in 1984 and 1995. The chemical composition of waters produced by the springs is of sulfate alkaline type. It was found, according to the Na:K:Mg relative content that most hot springs are located in the partial equilibrium zone, whereas the lowest temperature hot springs shift toward the groundwaters domain. The temperature estimated from gas geothermometry was 187 degrees celsius. It was found that the He has a deep origin, whereas the N{sub 2} is of atmospheric origin. Methane was not detected, suggesting that equilibria between gases and the liquid phase was reached at temperatures over 150 degrees celsius. The chemical compositions for the springs at Recubichi and Piedras de Lumbre zones are similar, so, it suggests that they have the same origin. The water quality of the springs for agricultural use, is classified between C2-S2 and C2-S3 types, that suggest that this water can be used for irrigation. The arsenic element was not detected and the concentration for the boron element is lower that 0.175 ppm. [Espanol] Los analisis quimicos de agua de 12 manantiales y 4 fumarolas de las zonas de Recubichi y Piedras de Lumbre, Chihuahua, Mexico fueron estudiados con el fin de conocer las caracteristicas geoquimicas del acuifero somero y su interaccion con fluidos geotermicos. Se realizaron 2 muestreos tanto de agua como de gases en 1984 y 1995. En ambos muestreos se encontro que la composicioon quimica del agua de todos los manantiales es del tipo sulfatado-sodico. De acuerdo con el contenido relativo de Na:K:Mg el agua de los manantiales mas calientes (93 grados celsius), se ubica en la zona de equilibrio parcial, mientras que en los de menor
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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.
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Energy Technology Data Exchange (ETDEWEB)
Pena, Wagner; Briceno, Jorge A., E-mail: wpenac@cia.ucr.ac.c [Univ. de Costa Rica, Centro de Investigaciones Agronomicas (Costa Rica); Leiros de la Pena, Maria del Carmen [Univ. de Santiago de Compostela, Dept. Edafologia y Quimica Agricola (Spain)
2005-07-15
The use agricultural and forest soils is normal in the territory of the Autonomous Community of Galicia for submitting the physical, chemical and agroclimatic optimum. The region has areas by the characteristics of the environment has been impossible to use agricultural and forestry. Serpentinite soils developed on frequently drew attention to the high degree of infertility, caused by nutrient deficiency and excess toxic metal content. The results of general physical and chemical properties have been analyzed of the total metal content and biochemical parameters of 28 soils on serpentinite in A Coruna Galicia, Spain. The infertility of soil organic matter, nutrients and low microbial activity and biochemistry have been caused by high level of pH and nutritional imbalance due to the high content of Mg{sup 2+}. OM (organic matter) content, total N, soluble P and exchangeable K{sup +}, were lower due to the underdevelopment of vegetation and the potential toxic effects that have metal on the biological activity in the middle. (author) [Spanish] El uso agricola y forestal de los suelos es normal en el territorio de la Comunidad Autonoma de Galicia por haber presentado las condiciones fisicas, quimicas y agroclimaticas optimas. La region tiene zonas que por las caracteristicas del medio ha sido imposible el uso agricola y forestal. Los suelos desarrollados sobre serpentinita es frecuente que hayan llamado la atencion por el elevado grado de infertilidad, provocado por la deficiencia de nutrimentos y por el exceso contenido en metales toxicos. Los resultados de las propiedades generales fisicas y quimicas han sido analizados del contenido total de metales y de parametros bioquimicos de 28 suelos sobre serpentinita en A Coruna, Galicia, Espana. La infertilidad de los suelos de materia organica, nutrimentos y baja actividad microbiana y bioquimica han sido causadas por el alto nivel de pH y el desbalance nutricional por el alto contenido de Mg{sup 2+}. El contenido de MO
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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)
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International Nuclear Information System (INIS)
2007-12-01
The quality of the air in the city of Asuncion was evaluated, studying the distribution of the main chemical elements that are present in the sampling sites, using Bio monitors Tillandsia Meridionalis Baker and Tillandsia Recurvata L. and analyzed by of the ray-x florescence, technique the data were analyzed by means of the AXIL software and the results were a statistically analyzed by the SPSS Software for the creation of the maps of concentration distribution of the different elements from interest. The project was carried out multidisciplinary group integrated by the CNEA as Coordinator and executor; the Facultad de Ciencias Agrarias; the Facultad de Ciencias Quimicas; the Facultad de Ciencias Exactas y Naturales of the Universidad Nacional de Asuncion, as well as the Municipalidad de Asuncion.The material was done by specialists in the field and with the financial support of the IAEA [es
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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
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COMPONENTES MINORITÁRIOS DO ÓLEO DE MAMONA (Ricinus comunnis L.
Directory of Open Access Journals (Sweden)
Elina Bastos Caramão
2007-12-01
Full Text Available O óleo extraído de sementes de Ricinnus communis L., conhecida como mamona, foi analisado neste trabalho quanto a presença decomponentes minoritários extraídos na fase insaponificável. A extração de insaponificáveis foi realizada conforme o método AOCS(Ca 6a-40 e a análise das amostras de óleo foi realizada por Cromatografia gasosa acoplada a espectrometria de massas (CG-DEMapós derivatização com BSA. Entre as substâncias identificadas encontrou-se o D-tocoferol, g- tocoferol, D5-ergostenol, stigmasterol,obtusifoliol, g-sitosterol, fucosterol e cicloartenol. As amostras de óleo de diferentes variedades de mamona, obtidas por prensagem afrio e por solvente em extrator soxhlet apresentaram diferenças quanto as substâncias separadas. O método empregado para extração eanálise foi apropriado para identificar a presença de componentes minoritários no óleo de mamona.
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Síntese e propriedades fotoluminescentes do óxido de cério dopado com magnésio
Directory of Open Access Journals (Sweden)
G. P. Casali
2014-09-01
Full Text Available Neste trabalho são investigadas as propriedades ópticas de fotoluminescência do óxido de cério dopado com magnésio na forma de pós para analisar a influência dos sais precursores dos íons de interesse sobre a morfologia e as propriedades ópticas e para avaliar as propriedades ópticas com excitação em diferentes comprimentos de onda na região do visível e ultravioleta. Os pós foram obtidos pelo método dos precursores poliméricos. A caracterização estrutural dos materiais obtidos foi feita por difração de raios X. A estrutura e a simetria dos materiais foram estudadas por espectrometria de espalhamento Raman. As curvas de transmissão foram avaliadas por espectroscopia eletrônica na região UV-Vis. As propriedades ópticas foram avaliadas por espectroscopia de fotoluminescência e a microestrutura por microscopia eletrônica de varredura
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Energy Technology Data Exchange (ETDEWEB)
Huato Soberanis, Julio; Ogura, Tetsuya [Universidad Autonoma de Guadalajara, Guadalajara, Jalisco (Mexico)
1995-02-01
A spectrophotometric method to determine As in tortilla and lime has been optimized, modifying the AsH{sub 3} generator. The reaction between arsin (AsH{sub 3}){sub 4} and diethyldithiocarbamate of Ag (AgDDC); was followed spectrophotometrically. The conditions under which the As remains in the ash during the calcination of the tortillas were studied. It was found that when they were heated in a quartz tube with a careful control of the air flow and oxygen, as well as the heating temperature, the arsenic loss in minimized. [Spanish] Se ha optimizado el metodo para determinar As en la tortilla y cal mediante espectrometria en el visible del color producido en la reaccion entre Arsina (AsH{sub 3}){sub 4} y dietilditiocarbamato de plata (AgDDC); modificando el generador de AsH{sub 3}. Se han buscado las condiciones en las que el arsenico permanece en las cenizas de la calcinacion de las tortillas; encontrandose que las tortillas deben calentarse en un tubo de cuarzo con control del flujo de aire y oxigeno asi como de la temperatura de calentamiento.
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Separation of the components of the TBP-H2 MBP-HDBP-H3PO4 mixture
International Nuclear Information System (INIS)
Pires, M.A.F.; Abrao, A.
1981-04-01
Several schemes for the separation of dibutylphosphoric acid (HDBP), monobutylphosphoric acid (H 2 MBP) and orthophosphoric acid (H 3 PO 4 ) as hydrolytic and radiolytic degradation products from tri-n-butylphosphate (TBP) were studied. For the resolution of a HDBP, H 2 MPB and H 3 PO 4 mixture in TBP-diluent, or in TBP-diluent-heavy metal nitrate (U-VI, Th-IV or Zr-IV), techniques such as ion exchange chromatography, ion chromatography and separation onto a chromatographic alumina column were investigated. For the identification, determination and analytical resolution following up for the several systems studied, techniques such as refraction index measurement, electrical conductivity measurement, molecular spectrophotometry and gas chromatography were applied. Special emphasys was given to the separation using alumina column where the HDBP acid was retained and eluted selectively for its separation from TBP-varsol-uranyl nitrate mixtures. This analytical procedure was applied to the samples coming from the Uranium Purification Pilot Plant in operation at the Centro de Engenharia Quimica (IPEN). (Author) [pt
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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)
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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)
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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.
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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)
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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.
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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.
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Obtenção de gorduras low trans por interesterificação quimica
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
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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)
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Directory of Open Access Journals (Sweden)
José Roberto Pinto de Souza
2005-06-01
álises por cromatografia gasosa acoplada à espectrometria de massas e das espectrometrias no infravermelho, de ressonância magnética nuclear de 1H e de 13C e comparação com dados espectrais da literatura. Entre os constituintes isolados, concluiuse que o eugenol é um dos prováveis responsáveis pela atividade antifúngica de O. gratissimum, pois registros da literatura comprovaram a atividade deste constituinte contra várias espécies de fungos.
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Directory of Open Access Journals (Sweden)
Maristela Martins
2012-03-01
Full Text Available A study was carried out to evaluate the association of levels of radioactivity, selenium and aflatoxin in shelled Brazil nuts, which were classified in different sizes, for export. The selenium determinations were performed by inductively coupled plasma optical emission spectrometry (LOQ = 3.0 µg g-1, and aflatoxins were detected by Liquid chromatography-mass spectrometry (LOQ = 0.85 µg kg-1, recovery rates were between 92 and 100%. Radioactivity was measured by high-resolution gamma spectrometry. The selenium mean concentration was (22.7 ± 7.4 µg g-1. (n = 30. Mean activities determined for the following radium isotopes were: 15.77 Bq kg-1 for 224Ra, 104.8 Bq kg-1 for 226Ra and 99.48 Bq kg-1 for 228Ra. For 226Ra, the levels did not vary significantly with nut sizes, although such differences were observed for 224Ra and 228Ra. There was no statistically significant association between the level of selenium and the activity of radionuclides, however, there was correlation between the radionuclides. Aflatoxins above the quantification limit were not found.Um estudo foi realizado para avaliar a associação dos níveis de radioatividade, selênio e aflatoxinas em castanha-do-Brasil descascada, que foram classificadas em diferentes tamanhos, para exportação. As determinações de selênio foram realizadas por espectrometria de emissão óptica com plasma indutivamente acoplado (LOQ=3,0 µg kg-1 e aflatoxinas foram detectadas por LC-MSMS (LOQ=0,85 µg kg-1, as taxas de recuperação ficaram entre 92 e 100%. A radioatividade foi medida por espectrometria gama de alta resolução. A concentração média de selênio foi de (22,7 ± 7,4 µg g-1. (n = 30. A atividade média determinada para os radioisótopos foram: 15,77 Bq kg-1 para o 224Ra, 104,8 Bq kg-1 para 226Ra e 99,48 Bq kg-1 para 228Ra. Para 226Ra, os níveis não variaram significativamente com o tamanho das nozes, embora tais diferenças foram observadas para 224Ra e 228Ra. Não houve
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Development of lithium disilicate based glass-ceramics =
Fernandes, Hugo Alexandre Goncalves da Rocha
O principal objectivo deste estudo foi o desenvolvimento de vitroceramicos a base de dissilicato de litio no sistema Li2O-K2O-Al2O3-SiO2 contendo uma razao molar SiO2/Li2O muito afastada da do dissilicato de litio (Li2Si2O5) usando composicoes simples e a tecnica tradicional de fusao-vazamento de vidro de forma a obter materiais com propriedades mecanicas, termicas, quimicas e electricas superiores que permitam a utilizacao destes materiais em diversas aplicacoes funcionais. Investigou-se o fenomeno de separacao de fases, a cristalizacao e as relacoes estrutura-propriedades de vidros nos sistemas Li2O-SiO2, Li2O-Al2O3-SiO2 e Li2O-K2O-Al2O3-SiO2. Os vidros nos sistemas Li2O-SiO2 e Li2O-Al2O3-SiO2 apresentaram fraca densificacao e resultaram em materiais frageis, contrastando com a boa sinterizacao dos vidros no sistema Li2O-K2O-Al2O3-SiO2. Pequenas adicoes de Al2O3 e K2O ao sistema Li2O-SiO2 permitiram controlar a separacao de fases devido a formacao de especies de Al(IV) que confirmaram o papel de Al2O3 como formador de rede. Os compactos de po de vidro das composicoes contendo Al2O3 e K2O tratados termicamente resultaram em vitroceramicos bem densificados, apresentando dissilicato de litio como a principal fase cristalina, e valores de resistencia mecanica a flexao, resistencia quimica e condutividade electrica (173-224 MPa, 25-50 mg/cm2 e 2´10-18 S/cm, respectivamente) que possibilitam a utilizacao destes materiais em diversas aplicacoes funcionais. A adicao de P2O5, TiO2 e ZrO2 ao sistema Li2O-K2O-Al2O3-SiO2 como agentes nucleantes revelou que os vidros contendo apresentaram cristalizacao em volume, com a formacao de metassilicato de litio a temperaturas mais baixas e dissilicato de litio para as temperaturas mais elevadas, enquanto a adicao de zirconia reduz o grau de segregacao, aumenta a polimerizacao da matriz vitrea e desloca o valor de Tg para temperaturas superiores, inibindo a cristalizacao.
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Energy Technology Data Exchange (ETDEWEB)
Rogel-Ramirez, A [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: ARogelR@iingen.unam.mx
2008-10-15
This paper contains the description of a bidimensional Computational Fluid Dynamics (CFD), model Developer to simulate the flow and reaction in a stratified downdraft biomass gasifier, whereby Eulerian conservation equations are solved for particle and gas phase components, velocities and specific enthalpies. The model is based on the PHOENICS package and represents a tool which can be used in gasifier analysis and design. Contributions of chemical kinetics and the mixing rate using the EBU approach are considered in the gas phase global homogeneous reactions. The harmonic blending of chemical kinetics and mass transfer effects, determine the global heterogeneous reactions between char and O{sub 2}, CO{sub 2} and H{sub 2}O. The turbulence effect in the gas phase is accounted by the standard {kappa}-{epsilon} approach. The model provides information of the producer gas composition, velocities and temperature at the outlet, and allows different operating parameters and feed properties to be changed. Finally, a comparison with experimental data available in literature was done, which showed satisfactory agreement from a qualitative point of view, though further validation is required. [Spanish] Este estudio describe un modelo numerico bidimensional, basado en Dinamica de Fluidos Computacional (CFD), desarrollado para simular el flujo y las reacciones que ocurren en un gasificador estratificado de flujos paralelos, en el que se resuelven ecuaciones de conservacion Eulerianas para los componentes de la fase gaseosa, la fase solida, velocidades y entalpias especificas. El modelo esta basado en el codigo PHOENICS y representa una herramienta que puede ser utilizada en el analisis y diseno de gasificadores. En las reacciones globales homogeneas se consideran las contribuciones de la cinetica quimica y la rapidez de mezclado, usando el modelo Eddy Brake-UP (EBU). La medida harmonica de la cinetica quimica y la transferencia de masa, determinan las velocidades globales de
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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)
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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)
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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.
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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.
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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)
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Energy Technology Data Exchange (ETDEWEB)
Kochmann, Sonnia; Riquelme, Ildefonso [Division Tecnicas Analiticas Nucleares, Direccion de Investigacion y Ensenanza, Comision Nacional de Energia Atomica, San Lorenzo (Paraguay); Fernandez, Myriam; Vera Planas, Nestor [Laboratorio Quimico Biologico, Departamento de Investigacion de Delitos, Direccion de Apoyo Tecnico, Policia Nacional, Asuncion (Paraguay); Insauralde, Arieal; Sanabria, Felipe [Fisicoquimica Biologica, Facultad de Ciencias Quimicas, Facultad de Ciencias Quimicas, Universidad Nacional de Asuncion, San Lorenzo (Paraguay)
1999-07-01
The nuclear analysis its nondestructive characteristics of high sensibility, rapidity and specificity, offers optimal conditions for its application in forensic field, the determination of present metallic elements in the remainders of firings of, firearms like obtention of patterns that help systematic to distinguish originating remainders of other sources, like pyrotechnique devices or contamination of the labor environment, and but important, from the legal point of view, it contributes the certainty and it leaves the possibility of an expertise in a punishable fact taken to the court. [Spanish] Las tecnica analitica nuclear de espectrometria por fluorescencia de rayos X dispersiva en energia, por sus caracteristicas no destructivas de alta sencibilidad, rapidez y especificidad, brinda condiciones optimas para su aplicacion en en campo forense, en la determinacion de elementos metalicos presentes en los residuos de disparos de armas de fuego, asi como la obtension de patrones que ayuden a distinguir sistematicamente residuos provenientes de otras fuentes, como artefactos pirotecnicos o contaminacion del medio ambiente laboral, y lo mas importante, desde el punto de vista legal, aporta la certeza y deja abierta la posibilidad de una contrapericia en un hecho punible llevado a los estrados judiciales.
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Directory of Open Access Journals (Sweden)
Allegra YALLOUZ
2001-01-01
Full Text Available No presente trabalho, estudou-se o nível de mercúrio em atum sólido enlatado, comercializado na cidade do Rio de Janeiro. Foram analisadas 39 amostras, pertencente a 5 marcas e lotes distintos, utilizando-se a espectrometria de absorção atômica pela técnica de vapor-frio. Os resultados obtidos demonstraram que 53% das amostras apresentaram um teor acima do máximo recomendado, sendo que somente uma entre as cinco marcas estudadas apresentou todas as amostras com níveis dentro dos limites tolerados. Tais resultados demonstram a necessidade de um maior controle da qualidade destes produtos.The present study investigated the mercury levels in canned tuna fish, commercialized in the Rio de Janeiro city, Brazil. Thirty nine samples from five different makers were analyzed by cold vapor atomic absorption spectrometry. The results showed that 53% of the samples presented levels above the WHO (World Health Organization recommended value, and only one from the five suppliers presented all their samples below this level. Such results indicate that it urges a better quality control for this food.
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Substâncias voláteis em mel floral e mel de melato
Directory of Open Access Journals (Sweden)
CAMPOS Gisélia
2000-01-01
Full Text Available Embora pareça existir um "flavor" característico de mel, a grande variedade de flores disponíveis para a abelha, possibilita uma grande diversidade de flavor e aroma, indicando a presença de vários componentes voláteis. Alguns destes dependem da fisiologia da abelha, dos procedimentos após a colheita e no mel de melato há também a interferência de insetos sugadores e das formigas. Várias substâncias voláteis já foram identificadas, sendo algumas características de determinados méis uniflorais. Com o objetivo de encontrar uma substância volátil característica do mel de melato, seis amostras deste tipo de mel e seis amostras de mel floral foram analisadas usando extração por arraste de gás hidrogênio e cromatografia a gás acoplada a espectrometria de massas. Ácido acético foi encontrado em quatro amostras de mel de melato e em uma amostra de mel floral porém, com menor abundância.
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Directory of Open Access Journals (Sweden)
Fabiola Fernandes Galvão Rodrigues
2011-04-01
Full Text Available The essential oil from the fresh leaves of Lippia microphylla Cham. was obtained by hydrodistillation and characterized by gas chromatography-mass spectrometry (GC-MS. Major constituents of the oil were 1.8-cineole (18.12%, ƒÒ-ocimene (15.20%, bicyclogermacrene (11.63% and caryophyllene oxide (8.32%. Antimicrobial activity of the oil against Gram-positive and Gram-negative bacteria was determined by gel diffusion method. The oil showed good antibacterial activity against Shigella flexneri, Escherichia coli and Streptococcus pyogenes and very good antibacterial activity against Staphylococcus aureus.O oleo essencial das folhas frescas de Lippia microphylla Cham. foi obtido por hidrodestilacao e caracterizado por cromatografia gasosa acoplada a espectrometria de massas (CG-EM. O constituinte majoritario do oleo foi 1.8-cineol (18,12%, ƒÒ-ocimeno (15,20%, bicyclogermacreno (11,63% e oxido de caryophylleno (8,32%. A atividade antimicrobiana do oleo frente as bacterias Gram-positivas e Gramnegativas foi determinada pelo metodo de difusao em gel. O oleo apresentou uma boa atividade antibacteriana frente a Shigella flexneri, Escherichia coli e Streptococcus pyogenes sendo o melhor resultado frente a Staphylococcus aureus.
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Control of rare earths fractioning in a pilot unit, by emission optical spectrography
International Nuclear Information System (INIS)
Friedmann, R.
1978-01-01
A spectrochemical method has been developed for the determination of Y, Pr, Sm, Eu, Gd and Dy in purified lanthanum oxide; Y, La, Nd, Sm, Gd and Dy in purified cerium oxide and Y, La, Sm, Eu, Gd and Dy in neodymium oxide. The technique consists of an almost total consumption of the sample in a 17 amperes direct current arc. The rare erath oxides are mixed with an equal amount by weight of spectrographic graphite powder and the electrodes are arced in an argon(80%)-oxygen (20%) atmosphere, inside a specially designed chamber, to suppress cyanogen bands. The concentration ranges are approximately 0.002-2%, depending on the matrix and the elements to be analysed. The precision, accuracy and acceptability of the method are calculated for all elements. The total error values are approximately in the range of 18-48%. The method was developed for the quality control of the individual fractions held by pulsed and ion exchange columns in the lanthanide separations, in the Centro de Engenharia Quimica, Instituto de Energia Atomica, Sao Paulo [pt
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Energy Technology Data Exchange (ETDEWEB)
Pires, M A.F.; Abrao, A
1981-04-01
Several schemes for the separation of dibutylphosphoric acid (HDBP), monobutylphosphoric acid (H/sub 2/MBP) and orthophosphoric acid (H/sub 3/PO/sub 4/) as hydrolytic and radiolytic degradation products from tri-n-butylphosphate (TBP) were studied. For the resolution of a HDBP, H/sub 2/MPB and H/sub 3/PO/sub 4/ mixture in TBP-diluent, or in TBP-diluent-heavy metal nitrate (U-VI, Th-IV or Zr-IV), techniques such as ion exchange chromatography, ion chromatography and separation onto a chromatographic alumina column were investigated. For the identification, determination and analytical resolution following up for the several systems studied, techniques such as refraction index measurement, electrical conductivity measurement, molecular spectrophotometry and gas chromatography were applied. Special emphasis was given to the separation using alumina column where the HDBP acid was retained and eluted selectively for its separation from TBP-varsol-uranyl nitrate mixtures. This analytical procedure was applied to the samples coming from the Uranium Purification Pilot Plant in operation at the Centro de Engenharia Quimica (IPEN).
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Electricity and environmental conservation; Electricidad y conservacion del medio ambiente
Energy Technology Data Exchange (ETDEWEB)
Rivas, Elena [ed.] [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)
1999-07-01
This article presents a study on the environmental contamination of seven of the main fossil fuel power stations of the country. Experiment with water emulsions in fuel oil and with fluidized beds was carried out, which allow to burn fuels with efficiency, retaining the polluting compounds emitted to the atmosphere, which considers factors such as the wind turbulences, the atmospheric chemistry and the gas recirculation above the chimney, and the use of biogas to generate electricity which offers an ample potential of mitigation of the environmental contamination, characteristic of the garbage dumps. [Spanish] Este articulo presenta un estudio de contaminacion ambiental de siete de las principales centrales termoeletricas del pais. Se experimento con emulsiones de agua en combustoleo y los lechos fluidizados, los cuales permiten quemar combustibles con eficiencia reteniendo los compuestos contaminantes emitidos a la atmosfera, los cuales consideran factores como la turbulencia del viento, la quimica atmosferica y la recirculacion de gases sobre la chimenea, la utilizacion de biogas para generar electricidad el cual ofrece un amplio potencial de mitigacion de la contaminacion ambiental propia de los basureros.
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Energy Technology Data Exchange (ETDEWEB)
Lopes, Jansen M.; Lucas, Elisabete F. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas]. E-mail: elucas@ima.ufrj.br; Neves, Guilherme B.M. [COMAB Especialidades Quimicas Ltda., Rio de Janeiro, RJ (Brazil)]. E-mail: tecnico@comabrio.com
2003-07-01
One way of improving well production is the addition of demulsifier already in the gas lift. This is due to the apparent viscosity of water-in-oil emulsions being higher than apparent viscosity of crude oil, which in turn is higher than the apparent viscosity of an water-in-oil dual phase admixture and is also higher than the apparent viscosity of an oil-in-water emulsion. However, there are some situations where, in order to obtain separate flows of oil and water phases, demulsifier should be added in specific amounts in order to promote the desired phase separation. In heavy oils water and oil phase separation may be hard to obtain, however, the right demulsifier amount may imply in a considerable decrease in petroleum viscosity even without the appearance of two phases, making the flow easier. This work has evaluated the viscosity of a heavy crude having API degree 14 and BSW 52%, as a function of the addition of different amounts of DEMTROL BR 67, manufactured by Dow Quimica/Comab, Brazil, as demulsifier. (author)
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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
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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.
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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...
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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.
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Directory of Open Access Journals (Sweden)
Marco Antonio Vasconcelos Santos
2005-04-01
Full Text Available Inicialmente, desenvolveu-se um estudo para quantificar e comparar as concentrações de alguns metais presentes em duas amostras de hemolinfa do caramujo Biomphalaria glabrata (infectados e não-infectados com Schistosoma mansoni. A espectrometria de emissão óptica com fonte de plasma induzido (ICP-OES, foi utilizada para analisar os metais nas duas amostras. Os metais estudados foram: alumínio, cálcio, cádmio, cobalto, cromo, cobre, ferro, potássio, magnésio, manganês, chumbo e zinco. Os resultados mostram que, a princípio, os metais não são fatores determinantes no processo de defesa desses organismos contra este parasita, quando presente nos seus tecidos.We conducted a preliminary study to quantify and compare two concentrations of the same metals present in the hemolymph of snail Biomphalaria glabrata. In this context, we used Induction Coupled Plasma Optical Emission Spectroscopy technique (ICP-OES, to analyze the metals in the two samples (snails infected and not infected with Schistosoma mansoni. The metals studied were: aluminum, calcium, cadmium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, lead and zinc. Preliminary results showed that such metals are not involved in the defense of these organisms against the parasite, when present in their tissues.
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Sérgio Antônio Lemos de Morais
2005-06-01
Full Text Available Este estudo caracterizou a Lignina de Madeira Moída (LMM proveniente de Pinus oocarpa cultivado na região do Cerrado brasileiro. A LMM foi isolada e analisada por meio das espectrometrias no infravermelho com transformada de Fourier (IVTF, de ressonância magnética nuclear do próton e carbono-13 e por intermédio de métodos químicos de análise por via úmida. A LMM apresentou uma fórmula mínima igual a C9H9,2O2,6(OCH 30,8 e massas molares médias em massa (Mw e numérica (Mn de 3.969 e 1.133 Da, respectivamente. A LMM dessa madeira se enquadra dentro das ligninas típicas de coníferas.This work presents the characterization of the milled wood lignin (MWL of the Pinus oocarpa cultivated in the Brazilian cerrado. FTIR, carbon-13 and proton NMR spectroscopies as well as wet chemical methods were used. The established C9 unit formula for MWL was C9H9,2O2,6(OCH 30,8 and its relative molecular weights (Mw and (Mn were 3969 and 1133 Da, respectively. Pinus oocarpa MWL was typical of softwood lignins.
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Directory of Open Access Journals (Sweden)
Waldir Nagel Schirmer
2009-01-01
Full Text Available Adsorventes carbonados estão entre as melhores opções na remoção de compostos orgânicos voláteis (COV de correntes gasosas, pela boa afinidade que apresentam com compostos dessa natureza, além de baixo custo e disponibilidade. O presente trabalho avalia o desempenho do ciclo adsorção/dessorção de dois compostos orgânicos voláteis (fenol e tolueno em nanotubos de carbono (NTC comparativamente a um carbono grafitizado de aplicação tipicamente analítica (Carbotrap. As metodologias de amostragem e análise empregadas compreendem a coleta de gases por bombeamento (amostragem ativa em cartuchos (tubos, contendo o material adsorvente com posterior análise por cromatografia gasosa e espectrometria de massa (CG/EM, de acordo com o Método TO-17 da USEPA. Em relação ao desempenho dos adsorventes, o nanotubo obteve clara vantagem em relação ao Carbotrap, conseguindo reter mais adsorbato por massa de adsorvente. Além disso, não foi verificada interação diferenciada do fenol e tolueno com os dois adsorventes, tanto na etapa de adsorção quanto na de dessorção.
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Directory of Open Access Journals (Sweden)
Waldir Nagel Schirmer
2008-12-01
Full Text Available Adsorventes carbonados estão entre as melhores opções na remoção de compostos orgânicos voláteis (COV de correntes gasosas,pela boa afinidade que apresentam com compostos dessa natureza, além de baixo custo e disponibilidade. O presente trabalhoavalia o desempenho do ciclo adsorção/dessorção de dois compostos orgânicos voláteis (fenol e tolueno em nanotubos de carbono(NTC comparativamente a um carbono grafitizado de aplicação tipicamente analítica (Carbotrap. As metodologias deamostragem e análise empregadas compreendem a coleta de gases por bombeamento (amostragem ativa em cartuchos (tubos,contendo o material adsorvente com posterior análise por cromatografia gasosa e espectrometria de massa (CG/EM, de acordocom o Método TO-17 da USEPA. Em relação ao desempenho dos adsorventes, o nanotubo obteve clara vantagem em relação aoCarbotrap, conseguindo reter mais adsorbato por massa de adsorvente. Além disso, não foi verificada interação diferenciada dofenol e tolueno com os dois adsorventes, tanto na etapa de adsorção quanto na de dessorção.
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Encapsulation and re-use of wood industry waste: varnish powder
Directory of Open Access Journals (Sweden)
Acosta, A.
2006-06-01
Full Text Available The present article describes the findings of the first stageof the analysis of xiloarcilla, a material made of clayand a wood industry by-product, namely the wood andpolyurethane varnish powder pump-suctioned off woodcomponents during sanding and polishing. This powderwas added to the clay in proportions of from 1% to 5%by weight. The prime materials as well as the xiloarcillacompound were characterized, in the latter case primarilyto determine its physical-mechanical properties andchemical and environmental feasibility as a constructionmaterial.En este articulo se presentan los resultados obtenidos,en una primera etapa, del estudio del material que denominaremoscomo xiloarcilla, compuesto por arcilla y porun subproducto de las industrias de la madera, que eneste caso son los polvos del lijado y del barnizado y excedentesde estos productos utilizados en el acabado demuchos componentes de madera (PLB, estos polvos seadicionaron a la arcilla en cantidades entre el 1% y el5% del peso total del compuesto. Se realizo un estudiode caracterizacion de los materiales aislados y posteriormentedel compuesto xiloarcilla, con enfasis en el comportamientofisico-mecanico y su respuesta quimica ymedioambiental, como material de construccion.
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Bioequivalence of ciprofloxacin tablet formulations assessed in Indonesian volunteers.
Harahap, Y; Prasaja, B; Indriati, E; Lusthom, W; Lipin
2007-06-01
Determination of the bioequivalence of two ciprofloxacin tablet formulations (test formulation manufactured by Novell Pharmaceutical Laboratories, Indonesia, reference formulation from Quimica Farmaceutica Bayer, Spain). 24 healthy volunteers received each of the two ciprofloxacin formulations at a dose of 500 mg in a 2-way crossover design. Blood samples were obtained prior to dosing and at 0.5, 1, 1.5, 2, 3, 4, 6, 8, 10, 12 and24h after drug administration. Plasma concentrations of ciprofloxacin were monitored using high-performance liquid chromatography over a period of 24 h after administration. The pharmacokinetics parameter AUC0-24h, AUC0-infinity and Cmax were tested for bioequivalence after log-transformation of data and ratios of tmax were evaluated non-parametrically. The point estimates and 90% confidence intervals for AUC0-24h, AUC0-infinity and Cmax were 97.55% (92.71 - 102.6%), 97.63% (92.90 - 102.59%) and 95.84% (89.95 - 102.10%), respectively, satisfying the bioequivalence criteria of the European Committee for Proprietary Medicinal Products and the US Food and Drug Administration guidelines. These results indicate that two medications of ciprofloxacin are bioequivalent and, thus, may be prescribed interchangeably.
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Umolu, Patience Idia; Okoror, Lawrence Ehis; Orhue, Philip
2005-03-01
Human Immunodeficiency Virus and Hepatitis B virus are blood borne pathogens that can be transmitted through blood transfusion and could pose a huge problem in areas where mechanisms of ensuring blood safety are suspect. This study became necessary in a population where most of the blood for transfusion is from commercial blood donors. 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. Thirteen (10%) samples were HIV seropositive and 7(5.8%) were HBsAg positive. The age bracket 18 - 25years had the highest numbers of donors and also had the highest number of HBsAg positive cases (7.8%) while the age group 29 - 38years had highest number of HIV seropositive cases. High prevalence of HIV antibodies and Hepatitis B surface antigen was found among commercial blood donors. Appropriate and compulsory screening of blood donors using sensitive methods, must be ensured to prevent post transfusion hepatitis and HIV.
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EVALUACIÓN DE LA CALIDAD MICROBIOLÓGICA DEL AGUA ENVASADA EN BOLSAS PRODUCIDA EN SINCELEJO- COLOMBIA
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Jhon Vidal D
2009-08-01
Full Text Available Objetivo. Evaluar la calidad microbiológica y fisico-quimica del agua envasada en bolsas producidad en la ciudad de Sincelejo-Colombia con destino al consumo humano. Materiales y métodos. Para la estimación de organismos coliformes totales y fecales, Pseudomona aeruginosa y mesófilos en el agua envasada de 13 marcas, se utilizó el método de filtración por membrana (FxM. Resultados. El 92 % de las marcas de agua envasada en bolsa que se produce en la ciudad de Sincelejo presentaron bacterias mesófilas en su producto, mientras que en el 33% de ellas se encontraron coliformes totales. Cabe destacar que una marca presentó coliformes fecales, otra Pseudomonas aeruginosa y el reporte microbiano fue mayor en las envasadoras que poseían registro INVIMA. Conclusiones. Gran parte del agua envasada en bolsas de la ciudad de Sincelejo genera un riesgo a la salud de los consumidores, debido a la presencia de microorganismos patógenos, lo que está relacionado con inadecuados procesos de producción y a la intermitencia del suministro del agua utilizada como materia prima.
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Energy Technology Data Exchange (ETDEWEB)
Castro Sotelo, Laura Veronica [Instituto Politecnico Nacional, ESIQIE, Mexico, D.F. (Mexico)]. E-mail: lcastros@ipn.mx; Flores Oropeza, Eugenio Alejandro [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)]. E-mail: eaflores@imp.mx; Hernandez Garcia, Arnulfo [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: arte8080@hotmail.com; Vazquez Moreno, Flavio Salvador [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)]. E-mail: fvmoreno@imp.mx
2010-11-15
There are certain polymers that have the character to be flow modifiers, and this emerges of the chemical structure and molecular interaction that the polymers have with the crude oil. Three polymers were prepared by emulsion polymerization were characterized, they were characterized by Fourier transform infrared (FTIR) spectroscopy and Size exclusion Size exclusion chromatography (SEC). To assess its implementation, the polymers were evaluated in heavy crude oils with rotational tests. The polymer concentration was evaluated at 1000 ppm, and it presented an appreciable reduction of viscosity in heavy crude oil. [Spanish] Existen ciertos polimeros que tienen el caracter de ser modificadores de flujo, y esto surge de la estructura quimica y las interacciones moleculares que presentan estos al contacto con el aceite crudo. Se sintetizaron tres polimeros a traves de la tecnica de polimerizacion en emulsion, los polimeros fueron caracterizados por Espectroscopia Infrarroja con transformada de Fourier (FTIR), tambien se utilizo la tecnica de Cromatografia por Exclusion de Tamanos (SEC). Para valorar su aplicacion, se evaluaron en aceites crudos pesados con pruebas rotacionales. La concentracion de los polimeros se valuo en 1000 ppm, y se aprecio un notable abatimiento de la viscosidad del aceite crudo pesado.
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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
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Energy Technology Data Exchange (ETDEWEB)
Garcia-Orellana, Jordi [Universitat Autonoma de Barcelona (Spain)
2012-07-01
smaller masses. Though analytical techniques exist for determining {sup 210}Pb with {beta} spectrometry with proportional counters or liquid scintillation counters its application to the study of sedimentary cores is rare. [Spanish] El {sup 210}Pb es un emisor {beta}-{gamma}, con dos emisiones {beta} de energias E{sub 1max} = 63.1 keV y E{sub 2max} = 16.6 keV y una emision {gamma} de 46.5 keV. El hecho de ser doble emisor permite su determinacion directa mediante diferentes tecnicas, aunque tambien podemos determinar su actividad de forma indirecta mediante su descendiente el {sup 210}Po. La tecnica mas comun y que recomendamos para la determinacion del {sup 210}Pb en sedimentos costeros es la medida de {sup 210}Po por espectrometria {alpha}. En este tipo de registros podemos asumir que el {sup 210}Pb y su descendiente el {sup 210}Po se encuentran en equilibrio secular, aunque existe la posibilidad que en la parte superior del core esto no se cumpla siempre. Las ventajas de esta tecnica son que i) el procesamiento radioquimico de las muestras no es complicado, ii) los espectrometros {alpha} permiten un recuento rapido para obtener una estadistica aceptable (<10%) y iii) la cantidad de muestra que se requiere es pequena (de 0.2 a 1 g). La facilidad del tratamiento de las muestras y la sencillez del tratamiento espectral permite realizar perfiles exploratorios de los cores para determinar la calidad del perfil sedimentario antes del inicio de otros analisis. La medida directa del {sup 210}Pb mediante espectrometria {gamma} con detectores de Ge de alta resolucion es tambien muy comun. Las ventajas de esta tecnica son que: - se trata de una tecnica no destructiva y por tanto permite la reutilizacion de las muestras para otros analisis; - la preparacion de las geometrias de medida es sencilla y no necesita de procesos radioquimicos; - permite medir simultaneamente otros radionuclidos {gamma} de interes ({sup 137}Cs, {sup 241}Am, {sup 226}Ra, {sup 40}K y {sup 234}Th). Asimismo
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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)
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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)
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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)
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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
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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.
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EVALUACIÓN QUIMICA DE LA FIBRA EN SEMILLA, PULPA Y CÁSCARA DE TRES VARIEDADES DE AGUACATE
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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
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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.
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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.
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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.
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Variabilidade sazonal dos constituintes da própolis vermelha e bioatividade em Artermia salina
Directory of Open Access Journals (Sweden)
Lívio César Cunha Nunes
Full Text Available A própolis é uma substância resinosa coletada pelas abelhas de diversas partes das plantas. Sua composição depende da época, vegetação e local de coleta. Apresenta diversas atividades biológicas como antimicrobiana, antioxidante, antitumoral, dentre outras. Foi realizado estudo da variabilidade sazonal, nos meses de fevereiro, junho e outubro de 2006, dos constituintes voláteis da própolis vermelha de Pernambuco através da extração por headspace dinâmico e identificação por cromatografia gasosa acoplada com espectrometria de massas (CG-EM. Foram identificados 34 constituintes voláteis, sendo monoterpenos e monoterpenóides, sesquiterpenos e sesquiterpenóides, fenilpropanóides, aldeídos, cetonas e η-alcanos. Os constituintes majoritários foram o trans-anetol, α-copaeno e o metil cis-isoeugenol. Também foi realizado o perfil fitoquímico por cromatografia em camada delgada (CCD, através da qual os constituintes fenólicos foram identificados como majoritários. Com o extrato bruto metanólico da própolis, realizou-se o ensaio de letalidade em Artemia salina, que demonstrou DL50 de 18,9 µg/mL, sugerindo uma possível atividade antitumoral.
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Directory of Open Access Journals (Sweden)
Dorian Lesca de Oliveira
2010-08-01
Full Text Available Este estudo analisou as concentrações de metais pesados (Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb e Zn por espectrometria de absorção atômica de chama (FAAS e variáveis físico-químicas (pH, condutividade elétrica e temperatura in situ em amostras de águas superficiais da circunvizinhança do Aterro Municipal de Manaus e chorume. Amostras de água e chorume foram coletadas no período de estiagem e chuvoso com o objetivo de verificar a influência antrópica sobre o sistema hídrico composto pelos Igarapés: Matrinxã, Aracu, Acará, e Bolívia. Os dados obtidos foram submetidos a duas análises estatísticas exploratórias: Análise de Componente Principal (PCA e Análise de Agrupamento Hierárquico (HCA. Os resultados indicaram concentrações de metais pesados distintos conforme a estação do ano e elemento. A PCA revelou correlações significativas entre: Al, Cd, Fe, Mn, Ni e Pb assim como Zn e Co. A HCA e PCA mostraram que as características do sistema hídrico são semelhantes ao chorume na estiagem.
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Directory of Open Access Journals (Sweden)
Priscilla Fracalossi Riguetti
2015-01-01
Full Text Available Neste estudo analisaram-se as concentrações de manganês, zinco, cádmio, chumbo, mercúrio e crômio, em amostras de chorume coletado no aterro sanitário de Dourados/MS. Foram retiradas amostras de dois reservatórios, um com tratamento aeróbio e outro com tratamento anaeróbio. Foram realizadas quatro coletas de 2012 a 2013, compreendendo períodos de seca e de chuvas. As concentrações dos metais foram determinadas por espectrometria de absorção atômica, modalidade chama. A comparação de resultados entre os dois reservatórios e entre as coletas foi realizada empregando-se análise de variância com nível de confiança de 95%. A análise dos resultados mostrou diferenças, quanto à concentração dos metais, somente entre as coletas. Os elementos manganês, zinco e chumbo apresentaram maiores concentrações nos períodos chuvosos e os demais elementos nos períodos de seca. De forma geral, apenas o índice pluviométrico interferiu nas concentrações dos metais estudados, também não se observaram variações de pH e condutividade elétrica ao longo do experimento.
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Composição de voláteis e perfil de aroma e sabor de méis de eucalipto e laranja
Directory of Open Access Journals (Sweden)
Bastos Deborah Helena Markowicz
2002-01-01
Full Text Available Neste trabalho foram analisados os compostos voláteis de amostras de mel de eucalipto e laranja colhidos nos estados de São Paulo e de Minas Gerais. O isolamento dos voláteis foi realizado empregando-se uma técnica de ''headspace'' dinâmico, a separação efetuada por cromatografia gasosa de alta resolução e a identificação por espectrometria de massas, Índices de Kovats e padrões, quando disponíveis. Foram identificados no mel de laranja o benzaldeído, o óxido cis de linalol, n-heptanal, 6-metil-5-hepten-2-ona, octanal e fenilacetaldeído, e em mel de eucalipto, o nonanal, 2-heptanona, 2-heptanol, octanol e nonanol. A caracterização sensorial desses méis foi obtida por Análise Descritiva Quantitativa e a aplicação de Análise dos Componentes Principais aos dados revelou que os descritores ''queimado'' e ''sabor residual'' caracterizam o mel de eucalipto, enquanto ''floral'' e ''cera'' caracterizam o mel de laranja. Entre os compostos identificados, o nonanal e o nonanol apresentaram contribuição sensorial importante ao mel de eucalipto, enquanto o fenilacetaldeído e o benzaldeído foram relacionados com os principais descritores do mel de laranja.
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Caracterização e Beneficiamento Primário de Placas de Circuito Impresso (PCI de Telefones Celulares
Directory of Open Access Journals (Sweden)
Theo Antonio de Jesus
2015-12-01
Full Text Available Devido ao constante avanço tecnológico, uma grande quantidade de aparelhos é descartada por obsolescência tecnológica ou defeitos. Isto acarreta a contaminação do solo e do lençol freático, além de representar perda econômica pois as PCI (placas de circuito impresso dos telefones celulares são ricas em metais pesados e alguns metais valiosos. Com o objetivo de conhecer melhor a composição e concentração destas PCI de modo a otimizar os processos de reciclagem, foi realizada a caracterização das PCI através da digestão em água régia e da utilização das técnicas de DRx (difração de raios x e FRx (espectrometria de fluorescência de raios x. Os resultados proporcionaram conhecimento suficiente a respeito da composição e concentração dos principais metais das PCI. A presença de ouro, prata e cobre chama a atenção para o potencial econômico destes resíduos. Estudos são necessários para desenvolver os processos mais adequados com vistas a concentrar estes metais e viabilizar sua reciclagem.
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Directory of Open Access Journals (Sweden)
Raimundo Marcelino Silva Neto
2016-10-01
Full Text Available Polpa e suco de melão clarificado por microfiltração tangencial foram avaliados com relação as suas características físico-químicas e compostos aromáticos. A polpa do melão (Cucumis melo var inodorus foi extraída, tratada com as enzimas Pectinex Ultra SP-L e Celuclast e clarificada por microfiltração à pressão média de 3,0 bar. O suco clarificado apresentou-se incolor com uma leve tonalidade esverdeada. As características físico-químicas da polpa e do suco clarificado, como pH, brix, acidez titulável, turbidez, glicose, frutose, sacarose, foram identificadas, assim como seu perfil aromático por meio de micro-extração em fase sólida (SPME e cromatografia gasosa acoplada com espectrometria de massa (CG-EM. A microfiltração permitiu obter uma bebida de valor agregado partindo de uma matéria-prima de descarte do mercado externo, preservando suas características físico-químicas iniciais, indicando seu potencial de uso em blends de sucos de frutas tropicais. Adicionalmente, a fração retida poderá ser incorporada na polpa do melão e direcionada ao mercado de bebidas funcionais.
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Estabilidade térmica de embalagens de poli (tereftalato de etileno (PET: determinação de Oligômeros
Directory of Open Access Journals (Sweden)
Maria Teresa de A. Freire
1998-03-01
Full Text Available RESUMO: Embalagens plásticas para alimentos contendo poli(tereftalato de etileno (PET foram submetidas a diversas condições de aquecimento. Oligômeros foram identificados por cromatografia líquida de alta eficiência acoplada à espectrometria de massas, quantificados e usados como parâmetro de avaliação da estabilidade térmica do PET. Pequenas variações foram verificadas na distribuição dos oligômeros unicamente nas amostras aquecidas a 230 °C, o que sugere estabilidade térmica do PET nas condições de aquecimento utilizadas. Os resultados obtidos indicam que o uso do polímero é adequado para utilização como material de embalagem para alimentos a serem aquecidos em fornos convencionais ou de microondas.ABSTRACT: Polyethylene terephthalate (PET food packaging materials were submitted to different heating conditions. Oligomers were identified by high performance liquid chromatography coupled to mass spectrometry, quantified and used as parameter for the evaluation of thermal stability of the polymer. Small changes in oligomer distribution were observed only for samples heated at 230 °C, suggesting that PET is stable at the heating conditions employed. The results also suggest that the polymer is suitable as food packaging material intended for use in conventional and microwave ovens.
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Directory of Open Access Journals (Sweden)
Fernanda Salvato
2010-03-01
Full Text Available A implementação da espectrometria de massa (MS para as análises de peptídeos (MS e de aminoácidos (MS em tandem ou MS/MS tornou possível a identificação de centenas de proteínas em experimentos únicos. Uma grande variedade de estratégias está disponível atualmente para o fracionamento e a purificação de amostras, a identificação de proteínas, a quantificação, a análise de modificações pós-traducionais (MPT's e os estudos de interação. Dessa forma, a proteômica abre novas perspectivas na biologia de plantas com ênfase nos estudos de variabilidade genética, estresses fisiológicos e desenvolvimento de plantas.The implementation of mass spectrometry (MS for peptides (MS and amino acids (tandem MS or MS/MS analysis allowed the identification of hundreds of proteins in single experiments. A number of different strategies are current available for sample fractioning and purification, proteins identification, quantification, post-translational modifications (PTM and interaction analyses. In this way, the proteomics open up new perspectives in plant biology with emphasis on studies of genetic variability, physiological stresses and plant development.
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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.
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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)
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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.
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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.
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Energy Technology Data Exchange (ETDEWEB)
Arenas-Martinez, L.F [Universidad Autonoma de Coahuila, Coahuila (Mexico)]. E-mail: fernando.arenas@uadec.edu.mx; Garcia-Cerecero, G. [Corporacion Mexicana de Investigacion en Materiales S.A. de C.V., Saltillo, Coahuila (Mexico)
2012-10-15
The corrosion behavior of gas metal arc welding (GMAW) regions has been studied using potentiodynamic polarization and polarization resistance (LPR) techniques. Experiments were conducted in hydrogen sulfide (H{sub 2}S)-containing brine and in H{sub 2}S-free brine. Welds were made on API 5L X52 steel. Due to differences in their microstructure, chemical composition and residual stress level, weld regions exhibited different responses under H{sub 2}S corrosion. Base metal exhibited the highest corrosion rate (CR) and the most cathodic corrosion potential. [Spanish] Se estudio el comportamiento ante la corrosion de las regiones de soldadura de un cordon realizado por arco metalico con gas (GMAW) sobre un acero grado API X52 mediante las tecnicas de polarizacion potencio dinamica y resistencia a la polarizacion (LPR). Los experimentos se realizaron utilizando salmuera con 300 ppm de acido sulfhidrico (H{sub 2}S) y salmuera libre de H{sub 2}S como electrolitos. Debido a las diferencias en su microestructura, composicion quimica y el nivel de esfuerzos residuales, las regiones de soldadura mostraron diferentes respuestas a la corrosion por H{sub 2}S. El metal base exhibio la velocidad de corrosion (VC) mas alta y el potencial de corrosion mas catodico.
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Implementation perspective of a Radiological Agent Identification Laboratory - LIAR at CTEx
International Nuclear Information System (INIS)
Santos, Avelino; Silva, Jorge A.V.; Oliveira, Luciano S.R.; Vilela, Paulo R.T.
2011-01-01
Radiometric analysis at Centro Tecnologico do Exercito, CTEx, have been performed since 1980s, to be applied in the course of pre-operational and operational stages of a subcritical nuclear assembly which was set up into the extinct Instituto de Pesquisas Especiais, IPE. In that time, monitoring, that were based in analytical techniques of gamma spectrometry and total alpha/beta counting, were performed. Nowadays, the aptness of identify radiological and nuclear agents in environmental samples is a deficiency of Division of Defesa Quimica, Biologica e Nuclear, DDQBN, which is legatee of IPE nuclear duty. With the implementation of Laboratorio de Identificacao de Agentes Radiologicos, LIAR, the obsolescence of DDQBN equipment is been solved by the acquisition of modern spectroscopy systems which are supposed able to analyze CTEx environmental matrix samples, according to specific CNEN standard, as well as to perform works that concern diverse activities on civil defense, security, scientific advisory, research, and foreign trade areas. So, this work describes the implementation of LIAR at DDQBN of CTEx and analyses perspectives of its use. Basic functionality, stage of implementation, systems and analytical techniques are described. Finally, the work considers the importance and the foreseen outcomes of LIAR implementation on scientific, technological, economic, social and environmental areas. (author)
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Argentina's chemical makers seek government support
International Nuclear Information System (INIS)
Salles, F.
1993-01-01
Argentina's chemical industry association, Camara de la Industria Quimica y Petroquimica (CIQYP; Buenos Aires), has started negotiations with the government aiming to stem industry-wide losses, which reached $236 million during the past 18 months. CIQYP blames the poor performance on worldwide over-supply and falling prices, which have curbed exports, and low tariffs, which have spurred imports. It is calling for higher import tariffs and export incentives. The talks will also focus on a possible bond issue that would support companies willing to restructure and modernize operations. The main factor hindering competitiveness is what CIQYP president Alejandro Achaval calls Argentinean cost, including high energy costs, high provincial and federal taxes, and high financing charges. Since 1988, the industry has cut prices by 30%, formed mergers and joint ventures, closed 11 plants and started five new ones, slashed the workforce by 27%, and engaged in the government's privatization program. Meanwhile, plans to privatize 64% of aromatics producer Petroquimica General Mosconi(PGM) were derailed when potential bidders Diamond Shamrock, Shell, and Perez Companc refused for the second time to make offers on February 2. Jorge Olazabal, planning secretary of the Ministry of Defense, says PGM will be put up for sale again by March
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Implementation perspective of a Radiological Agent Identification Laboratory - LIAR at CTEx
Energy Technology Data Exchange (ETDEWEB)
Santos, Avelino; Silva, Jorge A.V.; Oliveira, Luciano S.R.; Vilela, Paulo R.T., E-mail: avelino@ctex.eb.br, E-mail: jalberto@ctex.eb.br, E-mail: luciano@ctex.eb.br, E-mail: pauloric@ctex.eb.br [Centro Tecnologico do Exercito (DDQBN/CTEx), Rio de Janeiro, RJ (Brazil). Div. de Defesa Quimica, Biologica e Nuclear
2011-07-01
Radiometric analysis at Centro Tecnologico do Exercito, CTEx, have been performed since 1980s, to be applied in the course of pre-operational and operational stages of a subcritical nuclear assembly which was set up into the extinct Instituto de Pesquisas Especiais, IPE. In that time, monitoring, that were based in analytical techniques of gamma spectrometry and total alpha/beta counting, were performed. Nowadays, the aptness of identify radiological and nuclear agents in environmental samples is a deficiency of Division of Defesa Quimica, Biologica e Nuclear, DDQBN, which is legatee of IPE nuclear duty. With the implementation of Laboratorio de Identificacao de Agentes Radiologicos, LIAR, the obsolescence of DDQBN equipment is been solved by the acquisition of modern spectroscopy systems which are supposed able to analyze CTEx environmental matrix samples, according to specific CNEN standard, as well as to perform works that concern diverse activities on civil defense, security, scientific advisory, research, and foreign trade areas. So, this work describes the implementation of LIAR at DDQBN of CTEx and analyses perspectives of its use. Basic functionality, stage of implementation, systems and analytical techniques are described. Finally, the work considers the importance and the foreseen outcomes of LIAR implementation on scientific, technological, economic, social and environmental areas. (author)
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Energy Technology Data Exchange (ETDEWEB)
Soto V, Federico; Obaya V, Adolfo; Guerrero, Claudia [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)
1996-06-01
In this work, we present the classification and identification of hazardous industrial residues. Mexico has had a wide industrial development in last years, for instance the chemical, steel and petroleum industries, and it has had important effects in the waste industrial generation from different processes. For this reason it is important to diffuse how the correct classification and identification of industrial wastes is made, for insuring their handling, treatment and adequate disposal. [Spanish] En este articulo se presentan los principales aspectos a considerar en la clasificacion e identificacion de los residuos industriales peligrosos. Mexico, considerado como un pais en vias de desarrollo, ha mantenido en los ultimos anos un amplio crecimiento industrial y uno de los mas altos del mundo en poblacion. Esta situacion ha orillado a intensificar la explotacion de los recursos naturales mediante la actividad minera, la siderurgica, la industria quimica, la petrolera, etcetera. Todo esto ha repercutido indudablemente en la generacion de residuos de tan diversa naturaleza como lo son los procesos y las materias primas involucradas, con caracteristicas que van desde los poco riesgosos hasta los altamente peligrosos. Por esta razon, la clasificacion e identificacion de los residuos peligrosos es de suma importancia para asegurar su adecuado manejo, tratamiento y disposicion.
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International Nuclear Information System (INIS)
Cotrim, Marycel Barboza; Sato, Ivone Mulako; Salvador, Vera Lucia R.; Dantas, Elizabeth Sonoda Keiko; Cantagallo, Maria Ines; Lemes, Marcos Jose L.; Scapin, Marcos Antonio; Sisti, Cristina; Silveira, Elias Santana; Furusawa, Helio Akira; Pires, Maria Aparecida Faustino
2003-01-01
The present work presents the participation of the Environmental Diagnostic Division Laboratories (MQA) at the intercomparison national and international laboratories, (PI/SABESP - Interlaboratory Sao Paulo, Brazil, Program; Program for Interlaboratorial Analytic Quality Control of Metals in Water (CBM/COMETRO); Programa para La Calidad de las Mediciones Quimicas (PCQM/INTI) - Argentine, and the Commission d'Etablissement des Methodes d'Analyse, France (CETAMA/CEA). Those essay providers have using statistical tests such as the t-Student, Zscore and Cochran and Grubbs for the data evaluations. The obtained results are presented involving the analytical such as atomic absorption spectrometry: flame, graphite oven and hydride generation (AAS), emission spectrometry with induced plasma (ICP-OES), X-ray fluorescence WD-XRFS), ion chromatography and voltametry (VRA). The elements such as B, Al, K, Mg, Ca, Cr, Fe, Co, Cu, Zn and Pb, and the anions such as Cl-, NO 3 - , SO 4 2- and F - , were determined at trace level (mgL -1 ), and the elements such as Cr, As, Cd, Pb e Hg, at the trace level (μgL -1 ) in water matrices. The evaluation of analytical results, in the period 1997 to 2002, demonstrate a continuous improvement evidencing the importance of Laboratories participation at those type of exercises
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Energy Technology Data Exchange (ETDEWEB)
Cotrim, Marycel Barboza; Sato, Ivone Mulako; Salvador, Vera Lucia R.; Dantas, Elizabeth Sonoda Keiko; Cantagallo, Maria Ines; Lemes, Marcos Jose L.; Scapin, Marcos Antonio; Sisti, Cristina; Silveira, Elias Santana; Furusawa, Helio Akira; Pires, Maria Aparecida Faustino [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: mecotrim@ipen.br, e-mail: imsato@ipen.br, e-mail: vsalvado@ipen.br, e-mail: esdantas@ipen.br, e-mail: cantagal@ipen.br, e-mail: mjllemes@ipen.br, e-mail: helioaf@ipen.br, e-mail: mapires@ipen.br
2003-07-01
The present work presents the participation of the Environmental Diagnostic Division Laboratories (MQA) at the intercomparison national and international laboratories, (PI/SABESP - Interlaboratory Sao Paulo, Brazil, Program; Program for Interlaboratorial Analytic Quality Control of Metals in Water (CBM/COMETRO); Programa para La Calidad de las Mediciones Quimicas (PCQM/INTI) - Argentine, and the Commission d'Etablissement des Methodes d'Analyse, France (CETAMA/CEA). Those essay providers have using statistical tests such as the t-Student, Zscore and Cochran and Grubbs for the data evaluations. The obtained results are presented involving the analytical such as atomic absorption spectrometry: flame, graphite oven and hydride generation (AAS), emission spectrometry with induced plasma (ICP-OES), X-ray fluorescence WD-XRFS), ion chromatography and voltametry (VRA). The elements such as B, Al, K, Mg, Ca, Cr, Fe, Co, Cu, Zn and Pb, and the anions such as Cl-, NO{sub 3}{sup -}, SO{sub 4}{sup 2-} and F{sup -}, were determined at trace level (mgL{sup -1}), and the elements such as Cr, As, Cd, Pb e Hg, at the trace level ({mu}gL{sup -1}) in water matrices. The evaluation of analytical results, in the period 1997 to 2002, demonstrate a continuous improvement evidencing the importance of Laboratories participation at those type of exercises.
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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 ...
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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)
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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.
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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.
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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)
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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)
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Directory of Open Access Journals (Sweden)
B. Aráoz
2004-03-01
Full Text Available From soils contaminated with polychlorinated biphenils (PCBs a strain of Alcaligenes sp. able to grow in a mineral medium with a commercial mixture of PCBs as carbon source was isolated. This strain consumed up to 200 ppm in seven days in laboratory conditions. After 24 h of incubation, some new congeners of PCBs could be recognized by mass spectrometry. Through the identification of these compounds it was possible to postulate examples of possible transformations by dechlorinations of penta- and tetra-chlorinated congeners into tri-chlorinated ones. The properties of the isolated strain are appropriate for bioremediation of contaminated areas and also for using in bioreactors in order to remove the xenobiotic chemical.A partir de suelos contaminados con bifenilos policlorados (PCBs se aisló una cepa de Alcaligenes sp. capaz de crecer en medio mineral con una mezcla comercial de PCBs como fuente de carbono. Esta cepa consumió hasta 200 ppm de PCBs en siete días de incubación en condiciones de laboratorio. En 24 horas de incubación se han podido detectar nuevos congéneres de PCBs mediante espectrometria de masa. La identificación de estos compuestos ha permitido postular transformaciones de congéneres penta- y tetra-clorados que originarían derivados triclorados. Las propiedades de la cepa aislada son apropiadas para biorremediación y para su uso en biorreactores para eliminar estos compuestos xenobióticos.
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Directory of Open Access Journals (Sweden)
F.G.G. PEDRO
2016-01-01
Full Text Available RESUMO O presente trabalho teve como objetivo determinar a composição centesimal (cinzas, umidade, proteínas, lipídeos e carboidratos totais e mineral (Na, K, Ca, Cu, Fe, Mg, Mn e Zn das plantas medicinais Barbatimão (Stryphnodendron adstringens (Mart. Coville, Carqueja (Baccharis trimera (Less D.C., Mangava-Brava (Lafoensia pacari A. St.-Hil., e Quebra Pedra (Phyllanthus niruri L. comercializadas no mercado do Porto de Cuiabá, MT. As amostras foram identificadas botanicamente por meio da exsicata feita no Instituto de Botânica da Universidade Federal de Mato Grosso, Campus Cuiabá. A composição centesimal foi determinada de acordo com as recomendações da Association of Official Analytical Chemists e a concentração dos minerais foi quantificada por Espectrometria de Absorção Atômica em Chama. Os resultados obtidos foram: umidade (7,72% a 12,10%; cinzas (1,64% a 8,44%; proteínas (2,36% a 9,35%; lipídeos (0,41% a 2,05%; carboidratos totais (72,09% a 82,37% e, foram encontradas diferenças significativas entre as amostras (p K>Zn>Cu>Mg>Mn>Ca>Fe. Os valores obtidos em 200 mL das infusões quando comparados aos índices diários recomendados para minerais sugerem que os chás avaliados podem ser fonte de minerais, principalmente de K e Mn.
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Maria Isabel VALLILO
2006-12-01
Full Text Available O presente trabalho teve como objetivoidentificar os componentes químicos voláteis quecontribuem para o aroma agradável exalado pelosfrutos de Campomanesia adamantium, Myrtaceae,popularmente conhecida por gabiroba ou guabirobacomum no cerrado. A caracterização química do óleoessencial (0,05% v/p foi realizada utilizando-se atécnica da cromatografia a gás, acoplada àespectrometria de massas (CG-EM. O resultadoda análise atesta a presença de 30 componentesentre monoterpenos de fórmulas químicas iguais aC10H14, C10H16; C10H18O, C11H18O2, e sesquiterpenos,de fórmulas químicas equivalentes a C15H24 eC15H24O no óleo dos frutos dessa espécie.The present work aimed to identify thevolatile chemical components that contribute forpleasant fragrance exhaled by fruits ofCampomanesia adamantium, Myrtaceae, popularlyknown as guabiroba or gabiroba. The chemicalcharacterization of essential oil was carriedthrough using technique of gas chromatographyconnected to mass spectrometry (GC-MS. Resultsof analysis certify the presence of 30 compoundsbetween monotherpenes C10H14, C10H16, C10H18O,C11H18O2 and sesquitherpenes C15H24, C15H24O inthe essential oil of the fruits of this species.
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C. Majolo
2014-09-01
Full Text Available Objetivou-se com este trabalho identificar, quantificar os constituintes, e avaliar a atividade antibacteriana dos óleos essenciais extraídos de rizomas de açafrão (Curcuma longa L. e gengibre (Zingiber officinale Roscoe cultivados nas condições de Manaus/AM frente a 14 salmonelas entéricas isoladas de frango resfriado. A extração dos óleos essenciais foi realizada utilizando-se aparelho tipo Clevenger e a composição determinada por Cromatografia Gasosa acoplada a Espectrometria de Massas (CG-MS. A atividade antibacteriana foi realizada com o emprego de técnica de microdiluição em caldo. O óleo essencial de gengibre se mostrou expressivamente mais eficiente do que o óleo de açafrão, tanto em termos de ação bacteriostática (concentração inibitória mínima de 2500 a 5000 µg.mL-1 quanto bactericida (concentração bactericida mínima de 5000 a 10000 µg.mL-1 observando-se variação apenas em duas as amostras em termos de resistência a ação bactericida deste óleo. Assim, o óleo essencial de gengibre, representa uma alternativa para o controle de Salmonella enterica, entretanto, demais estudos abordando o sinergismo com alimentos são indicados.
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Adélia Emília de Almeida
2008-12-01
Full Text Available A esquistossomose, uma importante doença no Brasil, é causada por trematódeo pertencente ao gênero Schistosoma, atingindo milhões de pessoas, numa das maiores regiões endêmicas dessa doença em todo globo. O principal objetivo desse trabalho foi sintetizar o derivado 6-formil-oxamniquina e avaliar sua atividade biológica. O derivado 6-formil- oxamniquina foi obtido por oxidação da oxamniquina com dióxido de manganês empregando diclorometano como solvente, à temperatura ambiente, por 24 horas. Sua obtenção foi confirmada por espectrometria na região de infravermelho e espectroscopia de RMN 13C e ¹H, apresentando atividade similar quando comparada à oxamniquina comercial (Mansil®.Schistosomiasis, an important disease in Brazil, is caused by a trematode of the genus Schistosoma, reaching millions of person in one of the most endemic region of this disease in the whole globe. The main goal of this work was to syntetize the 6-formyl-oxamniquine derivative and evaluate its biological activity. The 6-formyl-oxamniquine derivative was obtained by the oxidation of oxamniquine with MnO2, applying CH2Cl2 as solvent at room temperature for 24 hours. The obtaintion of 6-formyl-oxamniquine derivative compound was confirmed by IR spectroscopy and 13C NMR and ¹H NMR, presenting similar activity when compared to the commercial oxamniquine (Mansil®.
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C. R. SILVA
2011-04-01
Full Text Available
O estudo objetivou determinar a concentração de selênio nas unhas e na dieta consumida por 66 pré-escolares matriculados em um Centro de Educação Infantil do MunicÃpio de São Paulo. Para a obtenção do consumo alimentar foi utilizado o método de registro alimentar, com a aplicação da pesagem direta dos alimentos. Os teores de selênio na dieta e nas unhas foram determinados por espectrometria de absorção atômica em forno de graï¬ te. A ingestão média de selênio das crianças de 2 a 3 anos foi de 18,7μg/dia e das de 4 a 6 anos de 29,5μg/dia. Os teores de selênio nas unhas das crianças de 2 a 3 anos foi 0,50μg/g e nas de 4 a 6 anos 0,48μg/g. Os resultados sugerem que os pré-escolares recebem na instituição uma alimentação adequada com relação ao selênio.
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Directory of Open Access Journals (Sweden)
Michelli Barbosa de Andrade
2014-10-01
Full Text Available No Brasil, o chumbo metálico é obtido principalmente a partir da reciclagem de baterias de chumbo-ácido utilizando o processo pirometalúrgico, que é acompanhado da geração de uma escória que apresenta elementos como Fe, Si, S, Al, Ca, Zn, Pb. O objetivo deste trabalho foi de estudar a escória gerada no processo através da fluorescência e difração de raios X e de extrações utilizando o método de Tessier seguida da determinação das concentrações dos metais nos extratos por espectrometria de absorção atômica. Com os resultados da fluorescência de raios X, observou-se que a somatória das porcentagens dos elementos citados se aproxima a 97 %. Pela difração de raios X, detectou-se fases como: Pirrotita (Fe1-xS, Maghemita (Fe2O3, Fayalita (Fe2+2SiO4, Óxido de chumbo e alumínio (Pb2Al2O5, Hercinita (Fe2+Al2O4 e Óxido de chumbo (Pb2O3 e que nos extratos, estão presentes vários metais em concentrações variáveis, sendo que chumbo e ferro são encontrados geralmente em maior concentração.
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Roberta Gomes Coelho
2006-09-01
Full Text Available From the ethanol extract of the capitula and scapes of Syngonanthus bisulcatus (Koern Ruhland the flavonoids 5-hydroxy-7,4'-dimethoxy-6-C-beta-D-glucopyranosylflavone, isovitexin (5,7,4'-trihydroxy-6-C-beta-D-glucopyranosylflavone, luteolin (5,7,3',4'-tetrahydroxyflavone, lutonarin (5,3',4'-trihydroxy-6-C-7-O-beta-D-glucopyranosylflavone and 5,6,3',4'-tetrahydroxy-7-O-beta-D-glucopyrade were isolated. The structure of the compounds were characterized by spectroscopic methods, mainly 1D and 2D NMR experiments, as well as ESMS spectrometry. In addition we examined the effect of the ethanol extract of capitulae and scapes in the ulcer model ethanol/HCl-induced gastric mucosal lesions.Do extrato etanólico dos capítulos e dos escapos de Syngonanthus bisulcatus (Koern Ruhland foram isolados os flavonóides: 5-hidroxi-7,4'-dimetoxi-6-C-beta-D-glicopiranosilflavona, isovitexina (5,7,4'-triidróxi-6-C-beta-D-glicopiranosilflavona, luteolina (5,7,3',4'- tetraidroxiflavona, lutonarina (5,3',4'-triidroxi-6-C-7-O-beta-D-glicopiranosilflavona e 5,6,3',4'-tetraidroxi-7-O-beta-D-glicopiranosilflavona. As estruturas dos compostos foram caracterizadas por espectroscopia (RMN mono e bi-dimensionais e por espectrometria de massas Electrospray. Adicionalmente foram examinados os efeitos dos extratos etanólicos dos capítulos e dos escapos pelo modelo de úlcera induzida por etanol/HCl
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Geoquímica de solos do pantanal norte, Mato Grosso
Directory of Open Access Journals (Sweden)
Elaine de Arruda Oliveira Coringa
2014-12-01
Full Text Available A caracterização e análise geoquímica de solos permitem compreender os processos de migração, dispersão e concentração de elementos químicos no perfil, embasando a correlação dos atributos deles com as classes de solos formadas, o que possibilita inferências acerca das gêneses desses solos. Esta pesquisa teve por objetivos caracterizar e interpretar a composição geoquímica total de elementos maiores e menores em classes de solos representativas do Pantanal norte, na sub-região de Barão de Melgaço, Mato Grosso, Brasil. Foram selecionados 20 perfis das principais classes de solos do Pantanal e analisadas amostras dos horizontes A e B (ou C quanto à concentração de óxidos totais por espectrometria de fluorescência de raios-X, além das caracterizações física, química e mineralógica. Os solos subdividiram-se em dois tipos geoquímicos: um composto por textura arenosa a franco-arenosa com teores relativamente elevados de SiO2 e predominância de caulinita e quartzo, com menor teor de bases e elementos-traço; e outro composto por textura mais argilosa, geoquimicamente heterogêneos e com teores significativos de minerais 2:1, Al2O3, óxidos de Fe e Mn, bases e elementos-traço.
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CARACTERIZAÇÃO QUÍMICA E ATIVIDADE MUTAGÊNICA DO ÓLEO ESSENCIAL DE Lippia alba
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Thammyres de Assis Alves
2017-01-01
Full Text Available Os óleos essenciais são substâncias voláteis que vêm despertando interesse no setor agrícola, devido o grande potencial que possuem no controle de pragas. Assim, objetivo deste trabalho foi determinar a composição química do óleo essencial de folhas de Lippia alba e avaliar o seu potencial mutagênico. Para isso, o óleo essencial foi obtido por hidrodestilação, utilizando um aparelho do tipo Clevenger, seus constituintes químicos foram analisados por meio da cromatografia em fase gasosa com detector de ionização de chama (CG-DIC e de espectrometria de massas (CG-EM. Os compostos majoritários encontrados foram: geranial (29,83%, neral (20,71% e óxido de cariofileno (19,26%. A toxicidade do óleo essencial de L. alba foi avaliado em sementes de Lactuca sativa. O óleo essencial de L. alba inibiu 100% o crescimento radicular das sementes de L. sativa nas concentrações de 0,720% e 0,360% (m v-1. Nas outras concentrações testadas (0,180%, 0,090%, 0,045%, o óleo essencial apresentou um decréscimo no efeito de inibição conforme diminuição de sua concentração. Logo, o óleo essencial de L. alba possui potencial a ser usado como bioherbicida.
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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.
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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.
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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)
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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.
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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.
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Wastewater characterization of IPEN facilities - a preliminary study
International Nuclear Information System (INIS)
Monteiro, Lucilena R.; Goncalves, Cristina; Terazan, Wagner R.; Cotrim, Marycel E.B.; Pires, Maria Aparecida F.
2011-01-01
As part of IPEN's Environmental Monitoring Program, wastewater sample collection and analysis was implemented on a daily basis. CQMA- Centro de Quimica e Meio Ambiente was responsible for the determination of total, fixed and volatile solids, pH, metals (as Al, Sb, Ba, Cd, Pb, Co, Cu, Cr, Hg, Mo, Ni, Ag, Na, Zn, Ca, Mg, Be, Sn, Li, K, Sr, Ti and V), semimetals (As, B, Se and Si) and anions (such as chloride, nitrate, sulfate and fluoride). The results were compared to the legal values established by the Sao Paulo State regulation 8,468/76, which defines the maximum permitted values for most of the studied substances in wastewater, aiming its releasing in public wastewater treatment system. The evaluation of this parameters concentration on Ipen's effluent implies that 50% of the wastewater corresponds to organic matter due to the sanitary load and inorganic macro elements, mainly as sodium, potassium, calcium. The only parameter not found in accordance with Brazilian legislation was pH in four out of the one hundred and seven samples collected throughout 2009 (2.8% of the samples analyzed). This preliminary study showed the effluents generated at Ipen's facility is characterized by the presence of organic matter and macro elements, commonly found in sanitary wastewater and it is in compliance with Sao Paulo regulations. (author)
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Beatriz Milena Grajales Atehortúa
2015-03-01
Full Text Available El sauco Sambucus nigra es un arbusto con características botanicas, composicion quimica y sustancias activas, que ofrece las condiciones para ser aprovechado con fines medicinales, alimenticios, ornamentales, artesanales y para suplementación animal. Sobre la especie existen publicaciones sobre diversos temas en particular, sin embargo, no se cuenta con un documento que contenga informacion total sobre la especie. El objetivo de esta investigacion fue consolidar documentacion bibliografica sobre las caracteristicas, manejo y usos del sauco, que permita conocer ampliamente la especie y asi motivar su implementación en sistemas productivos generando beneficios sociales, ambientales y economicos, de tal manera que se puedan aprovechar todos los beneficios que esta brinda. Es asi como al final del articulo se dan recomendaciones sobre el manejo y uso del S. nigra en sistemas silvopastoriles del tropico alto, entre los que se tienen las cortinas rompe vientos, cercas vivas, sistema de ramoneo y banco de forraje mixto. Entre las alternativas en sistemas silvopastoriles, se tiene el sauco como especie multiproposito, el cual por sus propiedades permite ser implementado bajo diferentes herramientas de manejo del paisaje y proporciona forraje de buena calidad, mejora las condiciones de la leche, aporta en la protección de los recursos y en general ofrece diversidad de subproductos que pueden ser aprovechados.
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Energy Technology Data Exchange (ETDEWEB)
Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)
1995-12-31
The coatings applied by thermal projection have an important number of applications in different industries (chemical, oil, electric, nuclear, etc.). The main purpose of the protection by means of coatings is to alter the surface characteristics of a component so as to resist corrosive environments, abrasion and erosion, among others. The coatings can be applied by different methods, but due to the fact that its characteristics appreciably differ from the base metal, it is important the knowledge of its properties when a coating is selected for a specific use. In this article the characteristics of the applied coatings by thermal projection, the factors that affect its performance and the principal application techniques, are described. [Espanol] Los recubrimientos aplicados por proyeccion termica tienen un numero importante de aplicaciones en diferentes industrias (quimica, petrolera, electrica, nuclear, etc.). El proposito principal de la proteccion por medio de recubrimientos es alterar las caracteristicas de la superficie de un componente de manera que resista ambientes corrosivos, abrasion y erosion, entre otros. Los recubrimientos pueden aplicarse por diferentes metodos, pero debido a que sus propiedades difieren apreciablemente de las del metal base, es importante el conocimiento de sus propiedades cuando se selecciona un recubrimiento para un uso especifico. En este articulo se describen las caracteristicas de los recubrimientos aplicados por proyeccion termica, los factores que afectan su desempeno y las principales tecnicas de aplicacion.
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Energy Technology Data Exchange (ETDEWEB)
Porcayo Calderon, Jesus [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)
1996-12-31
The coatings applied by thermal projection have an important number of applications in different industries (chemical, oil, electric, nuclear, etc.). The main purpose of the protection by means of coatings is to alter the surface characteristics of a component so as to resist corrosive environments, abrasion and erosion, among others. The coatings can be applied by different methods, but due to the fact that its characteristics appreciably differ from the base metal, it is important the knowledge of its properties when a coating is selected for a specific use. In this article the characteristics of the applied coatings by thermal projection, the factors that affect its performance and the principal application techniques, are described. [Espanol] Los recubrimientos aplicados por proyeccion termica tienen un numero importante de aplicaciones en diferentes industrias (quimica, petrolera, electrica, nuclear, etc.). El proposito principal de la proteccion por medio de recubrimientos es alterar las caracteristicas de la superficie de un componente de manera que resista ambientes corrosivos, abrasion y erosion, entre otros. Los recubrimientos pueden aplicarse por diferentes metodos, pero debido a que sus propiedades difieren apreciablemente de las del metal base, es importante el conocimiento de sus propiedades cuando se selecciona un recubrimiento para un uso especifico. En este articulo se describen las caracteristicas de los recubrimientos aplicados por proyeccion termica, los factores que afectan su desempeno y las principales tecnicas de aplicacion.
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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)
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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)
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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.
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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)
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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)
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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)
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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)
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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.
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Relatório do Mestrado em Ensino da Fisica e de Quimica no 3º Ciclo do Ensino Básico
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
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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.
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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...
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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)
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Composição e fungitoxicidade do óleo essencial de capim citronela em função da adubação orgânica
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Ronice Alves Veloso
2012-12-01
Full Text Available O objetivo deste trabalho foi avaliar a influência da adubação orgânica sobre o teor e a composição do óleo essencial de capim citronela (Cymbopogon nardus, bem como a fungitoxicidade desse óleo ao crescimento micelial dos fungos Didymella bryoniae, Colletotrichum gloeosporioides e Amphobotrys ricini. A extração do óleo essencial foi realizada por hidrodestilação, a partir de plantas cultivadas em quatro doses de adubação orgânica (0, 3, 6 e 9 kg de esterco bovino curtido por cova, e a identificação dos constituintes químicos foi conduzida por cromatografia gasosa/espectrometria de massas. Para avaliar a inibição do crescimento micelial, o experimento foi instalado no delineamento inteiramente casualizado, em arranjo fatorial. Foram testadas sete alíquotas do óleo essencial (0, 5, 10, 15, 20, 25 e 30 µL, em cinco épocas de avaliação, com quatro repetições. O teor de óleo essencial do capim citronela não foi afetado pela adubação orgânica, e o óleo essencial do capim citronela apresentou 24 compostos químicos, entre estes monoterpenos e sesquiterpenos, com maior concentração dos compostos citronelal, β-citronelol, geraniol e elemol. O óleo essencial do capim citronela apresenta maior efeito de inibição a Amphobotrys ricini, em comparação aos fungos Didymella bryoniae e Colletotrichum gloeosporioides.
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Directory of Open Access Journals (Sweden)
Arnaldo Antonio Rodella
1999-07-01
Full Text Available Um sistema de análise química por injeção em fluxo é proposto para a determinação espectrofotométrica de zinco em amostras de misturas de fertilizantes minerais, empregando-se zincon como reagente cromogênico. O procedimento analítico envolve redução de íons metálicos por ácido ascórbico, complexação com íon cianeto, seguindo-se a descomplexação seletiva do zinco com formaldeído, liberando-o para que reaja com o zincon formando um complexo azul. A aplicação do método proposto à extratos de mistura de fertilizantes indicou que a ação de interferentes pode ser contornada e que resultados comparáveis aos da espectrometria de absorção atômica são obtidos.A flow injection system for zinc analysis in mineral fertilizer mixtures is proposed using zincon as chromogenic reagent. The effect of interfering ions such as Cu2+, Fe3+, Mn2+ was eliminated by reduction (using ascorbic acid and complexation of these metal íons with cyanide, with zinc included. Zinc is allowed to react with zincon only after the destruction of the zinc cyano complex with formaldehyde. Flow injection analysis permitted efficient control of the reaction time so that only the zinc ion is set free to produce a blue complex with zincon. Zinc was determined in 16 fertilizer mixtures (3 replicates with precision and accuracy comparable to atomic absorption spectrometry.
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Estudo comparativo dos óleos voláteis de algumas espécies de Piperaceae
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J.M.O. Mesquita
Full Text Available O presente trabalho teve por objetivo a análise comparativa dos óleos voláteis de espécies da família Piperaceae. As espécies estudadas foram as seguintes: Piper aduncum, P. amalago, P. arboreum, P. cernuum, P. hispidum, P. regnelii, P. submarginalum, P. vicosanum e Pothomorphe umbellata. A análise dos óleos voláteis foi efetuada pela combinação de técnicas de Cromatografia de Fase Gasosa (CG e de Cromatografia de Fase Gasosa acoplada a Espectrometria de Massa (CG/EM. A porcentagem de identificação dos constituintes nas análises dos óleos voláteis de Piper aduncum, P. amalago, P. vicosanum, P. submarginalum e Pothomorphe umbellata, atingiu valores superiores a 80%. Houve predominância de compostos de natureza sesquiterpênica nas composições químicas das espécies analisadas, com exceção de P. hispidum, P. submarginalum e P. vicosanum onde a predominância na composição foi de monoterpenos. Pelos dados apresentados observou-se que, dentre os compostos majoritários, os mais freqüentes, nas 9 espécies estudadas, foram beta-pineno (9/9 e espatulenol (9/9, seguidos por E-cariofileno (8/9, óxido de cariofileno (8/9, germacreno D (7/9, alfa-pineno (7/9 e limoneno (6/9. Pela primeira vez se relata a composição dos óleos voláteis de P. submarginalum e P vicosanum.
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Constituintes voláteis de cafés "gourmet" e mole do cerrado do triângulo mineiro em função da torra
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Nascimento Evandro Afonso do
2003-01-01
Full Text Available Neste trabalho foi estudada a variação da composição dos voláteis de dois cafés "gourmet" e de um café mole em função do grau de torrefação. Os cafés provenientes de Araguari, cerrado do Triângulo Mineiro, foram submetidos à torra americana (grãos marrons claros, média (grãos marrons e forte (grãos pretos e, em seguida, moídos e submetidos a uma destilação por arraste de vapor em contra-corrente com diclorometano. A análise de cromatografia gasosa acoplada à espectrometria de massas (CG-EM dos constituintes voláteis mostrou que piridina, pirazina e derivados, furfural e derivados são os principais constituintes voláteis dos cafés analisados. Mostrou ainda que não é possível diferenciar os três tipos de café pelos compostos dominantes (concentração acima de 1% no aroma. Foi observado também que a torra afeta sensivelmente os resultados, sendo que a torra americana, usada normalmente na prova da xícara para classificação sensorial de cafés, produz alguns voláteis de forte impacto no aroma que não aparecem na torra média nem na forte, além de apresentar concentrações dos componentes mais comuns muito diferentes daquelas observadas nas outras duas torras.
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Directory of Open Access Journals (Sweden)
Migdalia Miranda Martínez
2016-06-01
Full Text Available En el presente trabajo se realizó el estudio de algunos parámetros fisico-químicos y químicos de las semillas de Plukenetia volubilis L. (Sacha inchi o maní del inca, que incluyó el estudio como droga cruda, la extracción y análisis por cromatografia gaseosa-espectrometria de masas del aceite fijo, así como la evaluación de su poder antioxidante. Se comprobó que las características fisico químicas de la droga cruda (humedad residual 11,87 ± 0,02%, cenizas totales de 5,26 ± 0,02%, cenizas insolubles en ácido clorhídrico 0,85 ± 0,03% se encontraban dentro del rango informado por la OMS para drogas vegetales. El rendimiento de aceite de las semillas fue del 32%y en su composición pudo corroborarse la presencia de: ácido dodecanoico; ácido tetradecanoico; octadeceno; ácido hexadecanoico; eicosano; ácido heptadecanoico; ácido 9,12 octadecadienoico; ácido 9,12,15 octadecatrienoico; ácido 16-metil heptadecanoico; tricosano; tetracosano; pentacosano; hexacosano; heptacosano; octacosano; nonacosano. En la evaluación antioxidante de las semillas, realizada por la técnica de FRAP (Ferric Reducing Antioxidant Power, se pudo apreciar que la especie mostró valores de potencial de reducciones superiores a los de la Vitamina e reconocido compuesto con capacidad reductora y considerado un potente agente antioxidante.
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Affonso Celso Gonçalves Júnior
2009-04-01
Full Text Available O presente trabalho avaliou a eficiência da biomassa seca de aguapé (Eichornia crassipes na remoção dos metais pesados cádmio (Cd, chumbo (Pb, cromo (Cr, cobre (Cu, zinco (Zn e níquel (Ni de soluções preparadas com estes metais. O delineamento utilizado foi inteiramente casualizado, com cinco tratamentos (soluções com diferentes concentrações dos metais pesados e quatro repetições. A biomassa seca permaneceu nas soluções dos tratamentos por um período de 48h, e nos intervalos de 1; 2; 3; 6; 12; 24; 36 e 48h após a instalação do experimento, coletaram-se alíquotas de cada tratamento, determinando-se a maior remoção de cada metal pesado pela biomassa seca do aguapé. Foi realizada digestão nitroperclórica na biomassa seca e determinação dos teores dos metais na biomassa e nas alíquotas por espectrometria de absorção atômica, modalidade chama. Para os metais Cd, Pb, Cr, Cu e Zn ocorreu remoção significativa pela massa seca do aguapé nos diferentes tratamentos, enquanto para o Ni não foi encontrada diferença significativa. Dessa forma, conclui-se que a biomassa seca produzida, a partir do aguapé Eichornia crassipes, é um excelente material para a remoção, tanto em pequena como em grande escala, de corpos hídricos contaminados com metais pesados.
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José G. M. da Costa
Full Text Available Tendo em vista que bactérias resistentes a antimicrobianos representam um desafio no tratamento de infecções, é notória a necessidade de encontrar novas substâncias com propriedades antimicrobianas para serem utilizadas no combate a esses microrganismos. Este trabalho relata a avaliação da atividade antibacteriana, toxicidade e identificação dos componentes químicos do óleo essencial de Croton zehntneri (variedade estragol, planta utilizada na medicina popular como calmante e estimulante do apetite. A atividade antimicrobiana e a concentração inibitória mínima (CIM foram determinadas pelo método de difusão em discos. A avaliação da toxicidade foi realizada frente à Artemia salina com resultado considerado ativo (CL50 < 100 µg/mL. O óleo essencial das folhas apresentou atividade antibacteriana frente a todas as bactérias testadas exceto contra Salmonella typhimurium, sendo o melhor resultado frente a Shigella flexneri com CIM de 50 µg/mL. A análise da composição química foi obtida por cromatografia gasosa acoplada a espectrometria de massa (CG/EM e permitiu identificar um total de 97,4% dos componentes, com presença majoritária de estragol (76,8%. A presença de tal constituinte nos impulsiona a realização de estudos com outras bactérias, já que o estragol foi anteriormente relatado como sendo responsável por atividades antibacterianas.
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Cuesta, C; Ródenas, S; Merinero, M C; Rodríguez-Gil, S; Sánchez-Muniz, F J
1998-09-01
To investigate the hypercholesterolemic effects of a dietary exchange between 16:0 and 18:1 while 18:2 was at relatively lower level (approximately 4%) in aged women with initially high total serum cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) values and with high intakes of dietary cholesterol. Subjects were assigned to two consecutive 28 d periods. In the first period all subjects followed an oleic acid-rich diet in the form of oleic acid-rich sunflower oil. This was followed by a second period rich in palmitic acid in the form of palmolein. Nutrient intakes, serum lipids, lipoproteins, antioxidant vitamins, peroxides and LDL-peroxides were measured at two dietary periods. Instituto de Nutrición y Bromatología (CSIC), Departamento de Nutrición y Bromatología I (Nutrición) and Sección Departamental de Quimica Analítica, Universidad Complutense, Madrid, Spain. The palmolein period led to an increase in TC (P or = 6.21 mmol/L or with TC 6.21 mmol/L than in women with TC < 6.21 mmol/L, but palmolein decreased serum and LDL-peroxide in hypercholesterolemics more than in the normocholesterolemics, resulting in serum and LDL-peroxide levels which theoretically are more adequate. Though palmolein increased LDL-C concentrations, it better protected LDL particles, mainly in women with high TC, against peroxidation than did oleic acid-rich sunflower oil.
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Evaluation of the Olympus AU-510 analyser.
Farré, C; Velasco, J; Ramón, F
1991-01-01
The selective multitest Olympus AU-510 analyser was evaluated according to the recommendations of the Comision de Instrumentacion de la Sociedad Española de Quimica Clinica and the European Committee for Clinical Laboratory Standards. The evaluation was carried out in two stages: an examination of the analytical units and then an evaluation in routine work conditions. The operational characteristics of the system were also studied.THE FIRST STAGE INCLUDED A PHOTOMETRIC STUDY: dependent on the absorbance, the inaccuracy varies between +0.5% to -0.6% at 405 nm and from -5.6% to 10.6% at 340 nm; the imprecision ranges between -0.22% and 0.56% at 405 nm and between 0.09% and 2.74% at 340 nm. Linearity was acceptable, apart from a very low absorbance for NADH at 340 nm; and the imprecision of the serum sample pipetter was satisfactory.TWELVE SERUM ANALYTES WERE STUDIED UNDER ROUTINE CONDITIONS: glucose, urea urate, cholesterol, triglycerides, total bilirubin, creatinine, phosphate, iron, aspartate aminotransferase, alanine aminotransferase and gamma-glutamyl transferase.The within-run imprecision (CV%) ranged from 0.67% for phosphate to 2.89% for iron and the between-run imprecision from 0.97% for total bilirubin to 7.06% for iron. There was no carryover in a study of the serum sample pipetter. Carry-over studies with the reagent and sample pipetters shows some cross contamination in the iron assay.
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Caracterização físico-química de misturas de óleos vegetais para fins alimentares
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Katcilanya Menezes Almeida
2013-05-01
Full Text Available Objetivou-se, com este trabalho, a elaboração e caracterização de misturas especiais de óleos vegetais para fins alimentícios, com base nos óleos de amendoim, gergelim, maracujá e soja. Os óleos de amendoim e gergelim foram extraídos de sementes das cultivares BRS-Havana e BRS-Seda, respectivamente, cedidas pela Embrapa Algodão enquanto o óleo de maracujá foi adquirido no comércio de São Paulo e o de soja no de Campina Grande. As misturas foram elaboradas com base em uma matriz de planejamento experimental e, em seguida, submetidas aos ensaios físico-químicas (umidade, índice de acidez, índice de iodo, índice de refração, densidade e viscosidade segundo a metodologia do IAL (2008. Os resultados foram submetidos à análise de variância (ANOVA por delineamento inteiramente casualizado com 17 tratamentos e 6 variáveis pelo software ASSISTAT versão 7.6 beta. Todas as misturas diferiram estatisticamente entre si a nível de 1% pelo teste de Tukey e apresentaram-se aptas para fins alimentares, com influência da significante quantidade de ácidos graxos insaturados em todas as medidas físico-quimicas. Os óleos de maracujá e soja são quimicamente semelhantes.
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Energy Technology Data Exchange (ETDEWEB)
Hernandez R, Aurelio; Romero S, Antonio; Gomez G, Herminia [Instituto Politecnico Nacional, Mexico, D.F. (Mexico)
1996-02-01
The objective of this paper is to explain the programs that are contained in a Thermodynamic Computer System. Students can use this Computer System to make complicated calculations that are required in Thermodynamic Analysis. One of this programs is used to obtain the expression of heat capacity of pure substances in terms of temperature, at constant pressure. A database of pure substances has been created which retrieves the thermodynamic properties (enthalpy, entropy and Gibbs free energy) in such a format that it is very easy to understand. The changes of state functions for chemical reactions can also be calculated. Another program is used to estimate the equilibrium conditions in multicomponent and multiphase systems. [Spanish] En el presente trabajo se muestran los programas de computo que conforman un Sistema de Analisis Termodinamico desarrollado con el fin de facilitar los calculos y la comprension de algunos principios de la Termodinamica. Este sistema permite obtener la funcionalidad de la capacidad calorifica con la temperatura de sustancias puras, a presion constante; obtener de manera rapida y concisa las propiedades termodinamicas (entalpia, entropia y energia libre de Gibbs) de elementos y compuestos puros almacenados en una base de datos; determinar los cambios en las funciones de estado de reacciones quimicas entre sustancias puras; determinar el equilibrio en sistemas multicomponentes y multifasicos. Se indican los alcances de este grupo de programas de computo asi como su aplicacion a procesos practicos.
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Energy Technology Data Exchange (ETDEWEB)
Castaneda-Contreras, J. [Centro Universitario de Los Lagos, Universidad de Guadalajara, Guadalajara, Jalisco (Mexico)
2006-01-15
The sun-gel process is a chemical route that allows the manufacture of amorphous and poly-crystalline materials in a relatively simple way. New materials can be obtained, materials that through the traditional manufacture methods, are very difficult to obtain, such as oxide combinations (SiO{sub 2}, TiO{sub 2}, ZrO{sub 2}, etc.), and that, when being produced by traditional methods, they run the risk of being contaminated with rare earth ions or organic dyes. The unique structures, micro- structures and compounds that can be made with the sun-gel process open many possibilities for practical applications, to name a few: the manufacture of optical components, preforms for optical fibers, dielectric coatings, superconductors, waveguides, nanoparticles, solar cells, etc. [Spanish] El proceso sol-gel es una ruta quimica que permite fabricar materiales amorfos y policristalinos de forma relativamente sencilla. Se pueden obtener nuevos materiales que a traves de los metodos tradicionales de fabricacion son muy dificiles de obtener, tales como combinaciones de oxidos (SiO{sub 2}, TiO{sub 2}, ZrO{sub 2}, etc.), y que, de ser producidos por metodos tradicionales corren el riesgo de contaminarse con iones de tierras raras o colorantes organicos. Las estructuras unicas, micro estructuras y compuestos que pueden hacerse con el proceso sol-gel abren muchas posibilidades para aplicaciones practicas, por nombrar algunas, la fabricacion de componentes opticos, preformas para fibras opticas, recubrimientos dielectricos, superconductores, guias de onda, nanoparticulas, celdas solares, etc.
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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.
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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)
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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
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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.
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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)
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Energy Technology Data Exchange (ETDEWEB)
Rodas Grapain, Arturo
1999-07-01
One of the main problems involved in air quality models to calculate the pollutant concentration in a single point in the space and time, is the complexity of the numerical method. Even though the numerical methods are based on sophisticated and elaborated mathematics. They present two important and inevitable drawbacks: the stability of the numerical method. This means that its capacity to obtain reliable convergency in relation to the calculated values and real values is limited. The time and memory consumption. The high machine memory used to perform the numerical procedures and the time needed to prepare such procedures. Another problem is the mathematical basis of the structure of the air quality model. Commonly, simple models can perform quick estimations; however they are not exact contrary to the complex and elaborated models. In order to employ these complex models a high speed computer (workstations or Cray computer) is required. For this reason, this work presents a model approach with a relatively simple theoretical structure. The structure of this model named MOTTQUIP (modelo de transporte turbulento y quimica de plumas) can provide good results in point concentration operations. These results are compared with those obtained by two moderately complex mathematical models (Georgopoulos-Seinfeld and Lipphardt reactive plume models). The model developed in this work, shows a special feature where the solution of the differential equations are not involved explicitly. Therefore, it does not present the typical difficult in solving this kind of equations with the traditional numerical methods. [Spanish] Uno de los principales problemas que se presentan en los modelos de calidad del aire para el calculo de la concentracion de un cierto contaminante, para un punto dado en el espacio y en el tiempo, es la complejidad del metodo numerico involucrado para este fin, debido a que dichos metodos de calculo estan basados en matematicas sofisticadas y muy
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Directory of Open Access Journals (Sweden)
Camila Morais Gonçalves da SILVA
2012-12-01
Full Text Available Os chás mate e verde, comuns na dieta brasileira, foram avaliados primeiramente quanto a sua composição: os polifenóis totais e os flavonóides totais das matrizes alimentares in natura foram quantificados por espectrofotometria, enquanto o perfil de composição foi analisado por espectrometria de massas (ESI-MS. Posteriormente, a atividade antioxidante foi avaliada por ensaios in vitro, antes e após a biotransformação enzimática por lipase de pâncreas de porco e lipase de Aspergillus niger comerciais, nas condições de reação estabelecidas pelo fabricante. Amostras dessas matrizes foram avaliadas por diferentes métodos: FRAP, DPPH, co-oxidação β-caroteno/ ácido linoléico, ORAC e a peroxidação lipídica foi avaliada pelo índice de TBARS. Subsequentemente foi realizada uma comparação entre o potencial antioxidante dos chás in natura, sem biotransformação, com os chás liofilizados também não biotransformados, a fim de avaliar se o processo de liofilização poderia comprometer a capacidade antioxidante da amostra, já que este poderia ser utilizado como método de conservação das amostras para futuros testes. A biotransformação enzimática aumentou a atividade antioxidante de ambos os chás, enquanto o processo de liofilização não promoveu alterações no potencial antioxidante das matrizes estudadas, quando comparadas as amostras in natura.
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Revenli Fernanda do Nascimento
2017-05-01
Full Text Available Resumo O objetivo do trabalho foi determinar os teores de sódio (Na e potássio (K em refeições servidas em um restaurante universitário da região sul do Brasil, utilizando espectrometria de emissão atômica como método analítico. Foram coletadas 30 amostras de refeições do almoço e do jantar de um restaurante universitário, referentes a 131 diferentes cardápios no período de um semestre (4 meses, levando-se em conta o consumo de todos os alimentos oferecidos no cardápio, inclusive o suco e a salada temperada. Os resultados indicaram que o teor médio de Na em uma refeição ultrapassou o limite diário recomendado pela Organização Mundial da Saúde (OMS em 25 das 30 amostras analisadas. Observaram-se teores maiores em refeições compostas por algum tipo de alimento industrializado, como linguiças e batata palha, ou com pratos tradicionalmente temperados, como barreado. Os menores teores de Na estavam presentes em cardápios nos quais havia batata frita ou ovo. Os teores de K encontrados em 19 refeições poderiam ser considerados satisfatórios segundo a recomendação da OMS, no entanto, levando-se em conta que o consumo de K deve ser 1,75 vezes maior que o de Na em uma mesma refeição, a oferta de K foi baixa em todas as amostras analisadas.
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Luiz Erlon Araújo Rodrigues
1990-06-01
Full Text Available Os processos inflamatórios que se desenvolvem durante as etapas avançadas da esquistossomose mansônica hepática foram relacionados, com o acúmulo de siderossomos, a capacidade dos íons ferrosos/férricos de desencadearem a formação de radicais livres e aperoxidação de lipídios membranáceos, assim como à diminuição da estabilidade das membranas dos diversos componentes do compartimento lisossômico hepático. Os lisossomos isolados de figados de camundongos infectados por 100 cercárias, com 80 e 100 dias de infecção, foram respectivamente, 2,5 e quase 4 vezes mais frágeis que os controles, isolados de figados de camundongos não infectados. A presença de siderossomos em grande quantidade foi demonstrada por espectrometria aos raios-X.The inflammatory processes that develop during the advanced stages of hepatic Schistosomiasis mansoni have been related in this study to: (a accumulation of siderosomes; (b capacity of the ferrous/ferric ions to unleash the formation of free radicals; (c peroxidation of membranaceous lipids and; (d reduction of stability of the membranes of several components of the hepatic lysosomal compartment. The lysosomes isolated from the livers of infected mice by 100 cercariae, with 80 and 100 days of infection, were respectively 2.5 and almost 4 times weaker than the control ones isolated from livers of non-infected mice. The presence of a great quantity of siderosomes has been demonstrated by transmission electronic microscopy and X-ray spectrometry microanalysis.
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C.S. ROSA
2016-03-01
Full Text Available RESUMO A dengue está entre as doenças virais de propagação vetorial mais importante no mundo, causando sérios impactos de morbidade e mortalidade. Desta forma, o presente trabalho teve como objetivo analisar a composição química e a toxicidade do óleo essencial de Myrcia sylvatica (G. Mey D.C. frente Aedes aegypti e Artemia salina. Folhas de M. sylvatica foram coletadas no Parque Nacional da Chapada das Mesas, no município de Carolina (MA no mês de fevereiro de 2012. O óleo foi obtido por hidrodestilação e sua composição química foi determinada por cromatografia gasosa acoplada à espectrometria de massa (CG/EM. O bioensaio frente Artemia salina e às larvas de 3° estádio de Aedes aegypti foram realizados em diferentes concentrações. Os dados de mortalidade foram avaliados por regressão linear para determinar os valores de CL50. Obteve-se 0,5% de rendimento, sendo o (E-cariofileno o constituinte majoritário. O óleo essencial apresentou uma CL50 = 79,44 µg/mL frente A. salina, sendo considerado altamente tóxico. No entanto, este óleo não demonstrou efeito sobre as larvas de A. aegypti. Considerando que o teste de Artemia salina tem correlação com atividades biológicas de grande interesse terapêutico como antitumoral, o óleo essencial das folhas de M. sylvatica demonstrou potencial para desenvolvimento de produtos farmacêuticos.
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Carla Adriana Pizarro Schmidt
2009-08-01
Full Text Available Tendo em vista que o Brasil é um grande produtor e consumidor de café, fica evidente a importância de sua caracterização em diferentes locais de cultivo. O objetivo do presente estudo foi quantificar os teores de metais pesados em amostras de grãos de café, provenientes de lavouras implantadas em solos oriundos do basalto e do arenito Caiuá do Estado do Paraná. Foram examinadas 30 amostras de grãos de café, sendo 15 cultivados em solos predominantemente arenosos e 15 em solos argilosos. A determinação de Cromo (Cr, Cobalto (Co, Níquel (Ni, Chumbo (Pb, Cádmio (Cd, Cobre (Cu, Zinco (Zn e Manganês (Mn foi feita por espectrometria de emissão atômica com fonte de plasma induzido com Thermo Jarrel-ash ICAP 612 E (ICP-EAS. Os níveis foram variáveis entre as amostras.Considering that Brazil is a big producer and coffee consumer its evident the importance of its characterization in the different places of cultivation. The purpose of the present study was quantify the levels of high metals in coffee grains samples 'IAPAR 59' derived from farming introduced in basalt and Caiuá sandstone soils in Paraná, Brazil . Thirty ground samples were examined, being 15 of predominantly arenaceous ground and 15 of argillaceous ground. The determination of Chrome (Cr, Cobalt (Co, Nickel (Ni, Lead (Pb, Cadmium (Cd, Copper (Cu, Zinc (Zn and Manganese (Mn, was made through atomic emission spectrometry with induced plasma source with Thermo 612 Jarrel-ash ICAP E (ICP-EAS. The levels changed among the samples.
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Bianca L. Sadicoff
2001-06-01
Full Text Available Copolímeros graftizados de poliacrilamida e poli(óxido de propileno (PPO foram sintetizados via técnica de polimerização micelar. Foram investigadas as mudanças de viscosidade das suas soluções frente à variação do teor de monômero hidrófobo incorporado ao copolímero, adição de sal e de tensoativo. O maior teor de grupos hidrófobos resultou em aumento da viscosidade aparente das soluções poliméricas. A adição de sal provocou maior interação entre os grupos hidrófobos verificada pela desestabilização do sistema polimérico. A adição de tensoativos gerou decréscimo das viscosidades reduzidas das soluções poliméricas. Os copolímeros obtidos foram caracterizados, qualitativamente, por espectrometria de absorção na região do infravermelho (FTIR.Graft copolymers of polyacrylamide and poly(propylene oxide (PPO were synthesized by a micellar copolymerization technique. The rheological properties of the copolymers solutions were evaluated and compared with literature data for solutions of the same copolymers, synthesized by solution polymerization. The effect of hydrophobe content, salt addition and surfactant addition on the rheological properties were also investigated. Increasing hydrophobe content resulted in higher solution viscosities in the semi-dilute regime. Upon addition of salts, the hydrophobic groups associated to minimize their exposure to water. In the semi-dilute region, higher contents of surfactant added resulted in lower reduced viscosities of the polymer solutions. The copolymers were qualitatively characterized by infra-red spectrometry (IR.
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Zilda Cristina Gazim
2008-09-01
Full Text Available Terpenes and aroma volatiles from flowers of Calendula officinalis cultivated in southeastern Brazil were obtained by steam distillation (SD, headspace-cold finger (HS-CF extraction and headspace solid-phase microextraction (HS-SPME coupled with gas chromatography and mass spectrometric analysis. The dried flowers contained 0.1% oil. Kovats indices and mass spectra were used to identify 27 individual components in the various volatile fractions. The main components present in the volatile fractions of the C. officinalis flowers, obtained by SD, HS-SPME, and HS-CF, were δ-cadinene (22.5, 22.1, and 18.4 % and γ-cadinene (8.9, 25.4, and 24.9 % while 20.4 % of α-cadinol was seen only after SD extraction.Terpenos e aromas voláteis das flores de Calendula officinalis cultivados no sudoeste do Brasil foram isolados por arraste a vapor (SD, dedo frio (HS-CF e micro extração em fase sólida (HS-SPME acoplada à espectrometria de massas. As flores secas da C. officinalis contêm 0,1% de óleo essencial e foram identificadas 27 substâncias químicas através do cálculo do índice de Kováts e interpretação dos espectros de massas. As substâncias majoritárias presentes no óleo essencial das flores de C. officinalis, obtido por SD, HS-SPME e HS-CF foram δ-cadinene (22,5; 22,1 e 18,4 % γ-cadinene (8,9, 25,4 e 24,9 % e 20.4 % de α-cadinol foi observado apenas na extração por arraste a vapor.
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José Cleto da Silva Filho
1999-02-01
Full Text Available O presente trabalho teve como objetivo analisar alguns subprodutos agroindustriais utilizados na alimentação animal e identificar os principais minerais presentes. Amostras de farelos de algodão, arroz, canola, soja e trigo; farinhas de peixe, carne e penas + vísceras; cascas de algodão, arroz, laranja; bagaços de tomate e de laranja foram coletadas em diferentes locais de produção. O método analítico empregado foi a análise por ativação com nêutrons seguida de espectrometria gama. Os níveis de minerais encontrados em todas as amostras, inclusive aqueles considerados tóxicos, tais como As, Cd e Hg, não excederam os limites máximos permitidos em dietas para animais domésticos. Os valores obtidos foram comparados com os comumente encontrados em forragens.This study aimed to analyze some agroindustrial by-products used to feed animals in order to identify the presence of the main minerals. Samples of cotton seed meal, rice, canola, soybean and wheat; fish meal, feather meal, meat meal, feather plus viscera meal; rinds of cotton, rice, orange; citrus pulp and tomato residue were collected in different sites of production of the by-products. The method of analysis used was the neutron activation followed by gamma ray spectrometry. The levels of minerals found in all samples were compared with the levels commonly found in forages. The mineral concentration, even those of the toxic elements, as As, Cd and Hg, was at low level and did not exceed the maximum tolerable levels for domestic animals.
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Edmilson Cezar Paglia
2008-08-01
Full Text Available The distillation process was periodically monitored, on Campo Largo-PR, in “CHAMEL Ind. e Com. De Produtos Naturais LTDA.”, in the 2005 harvest. The hydrodistillation and GC-MS analyses were done in the UFPR Laboratories. The obtained data indicate that the chamomile essential oil extracted through the distiller model used presented low quality. Great part of the essential oil, besides their main components, it was being lost with the hidrolato. In the distillation process the periodic evaluation of quality and efficiency indicators is indispensable to establish appropriate operational conditions.Com o objetivo de avaliar o rendimento e a composição química do óleo essencial de camomila submetida a um sistema de extração por arraste de vapor, em escala comercial, monitorou-se periodicamente o processo realizado, no município de Campo Largo – PR, num modelo utilizado pela “CHAMEL Ind. E Com. de Produtos Naturais Ltda.”, na safra de 2005. As determinações analíticas foram realizadas em laboratórios da UFPR, por meio da hidrodestilação e cromatografia gasosa acoplada à espectrometria de massas. Os dados obtidos indicam que o óleo essencial da camomila extraído por meio do modelo de destilador utilizado apresentou qualidade aquém das expectativas. Grande parte do óleo essencial, inclusive seus principais componentes, estava sendo perdida junto ao hidrolato. No processo de destilação o monitoramento periódico de indicadores de qualidade e de eficiência é imprescindível para estabelecer condições adequadas de operacionalização.
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Richard Clayton Tomasella
2015-06-01
Full Text Available Métodos de tratamento avançado utilizando-se de materiais adsorventes alternativos podem substituir ou complementar tratamentos convencionais existentes, auxiliando na remoção de substâncias tóxicas provindas de diversos processos industriais. Espectrometria e testes biológicos (toxicidade aguda e crônica auxiliam no monitoramento dos rejeitos industriais, avaliando a eficiência desses sistemas alternativos de tratamento de efluentes. O trabalho objetivou promover a redução da concentração do chumbo (Pb e da toxicidade de um efluente industrial utilizando o potencial de compostos naturais (argilominerais e turfa e do carvão ativado (controle como adsorventes em ensaios em batelada. O carvão ativado permitiu remover 99,4% do Pb no efluente (15 min, e para os demais adsorventes a remoção ocorreu progressivamente até 24 horas, resultando em eficiências de remoção de 88,0% (argila do Vale do Paraíba - VP, 73,6% (argila de Ajapí - A e 63,5% (turfa. A toxicidade aguda foi completamente removida com a utilização do carvão ativado, enquanto eficiências de remoção maiores do que 50% foram obtidas utilizando compostos naturais. Efeito tóxico significativo não foi observado após o tratamento com o carvão ativado e argila VP com relação à toxicidade crônica. Os resultados indicam a possibilidade de utilização da argila VP como adsorvente de baixo custo comercial em métodos de tratamento avançado.
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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)
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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)
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Qualidade das águas cinza tratada com fitorremediação em unidades de produção agrícola
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Verena S. Baracuhy
2015-07-01
Full Text Available A irrigação é uma atividade que necessita de grande quantidade de água, o tratamento de águas cinzas provenientes de uma lavanderia pública em regiões semiáridas para reuso passa a ser uma alternativa de sobrevivência neste ambiente e favorável no desenvolvimento econômico sustentável. Nesse contexto, a pesquisa foi realizada no distrito de Ribeira no município de Cabaceiras - PB objetivando-se avaliar a qualidade da água cinza tratada com fitorremediação nas unidades de produção agrícola. Foram realizados dois tratamentos com(Tanque 2 e sem fitorremediação(Tanque 1, a cultura utilizada foi o capim elefante roxo. Foram coletadas amostras mensais e analisadas os seguintes parâmetros fisicoquimicos: Turbidez, pH, Condutividade elétrica (Ce, Demanda Quimica de Oxigenio(DQO e Fostoro Total. Para a turbidez os valores dos tratamentos foram acima de 1.000 UNT. Na demanda química de oxigênio, o valor mínimo foi de 311mg/L (setembro e máximo de 438mg/L (outubro no tanque 2 em contrapartida no tanque 1 o valor mínimo foi de 354mg/L (setembro e máximo de 618mg/L (outubro. O tratamento com fitorremediação teve uma maior eficiência na redução de DQO.Palavras – chave: capim elefante roxo, reuso, irrigação
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Zerovalent bismuth nanoparticles inhibit Streptococcus mutans growth and formation of biofilm
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Hernandez-Delgadillo R
2012-04-01
Full Text Available Rene Hernandez-Delgadillo1, Donaji Velasco-Arias2, David Diaz2, Katiushka Arevalo-Niño1, Marianela Garza-Enriquez1, Myriam A De la Garza-Ramos1, Claudio Cabral-Romero11Instituto de Biotecnologia, Centro de Investigacion y Desarrollo en Ciencias de la Salud, CIDICS, Facultad de Odontologia, Universidad Autonoma de Nuevo Leon, UANL, Monterrey, Nuevo Leon, 2Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Distrito Federal, MexicoBackground and methods: Despite continuous efforts, the increasing prevalence of resistance among pathogenic bacteria to common antibiotics has become one of the most significant concerns in modern medicine. Nanostructured materials are used in many fields, including biological sciences and medicine. While some bismuth derivatives has been used in medicine to treat vomiting, nausea, diarrhea, and stomach pain, the biocidal activity of zerovalent bismuth nanoparticles has not yet been studied. The objective of this investigation was to analyze the antimicrobial activity of bismuth nanoparticles against oral bacteria and their antibiofilm capabilities.Results: Our results showed that stable colloidal bismuth nanoparticles had 69% antimicrobial activity against Streptococcus mutans growth and achieved complete inhibition of biofilm formation. These results are similar to those obtained with chlorhexidine, the most commonly used oral antiseptic agent. The minimal inhibitory concentration of bismuth nanoparticles that interfered with S. mutans growth was 0.5 mM.Conclusion: These results suggest that zerovalent bismuth nanoparticles could be an interesting antimicrobial agent to be incorporated into an oral antiseptic preparation.Keywords: zerovalent bismuth nanoparticles, antimicrobial agent, biofilm, Streptococcus mutans
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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)
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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)
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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)
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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.
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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)
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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)
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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)
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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 frÃjol 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 dÃas de edad o ";;;nopalitos";;; (NT y pencas maduras (NM de 60 dÃas de edad y germinado de semillas de maÃz (GM del genotipo ASGROW 7573. Se cuantificó el contenido de materia seca (MS, proteÃna cruda (PC, lÃpidos totales (LT, cenizas (C, fibra cruda (FC y energÃa bruta (EB, asà 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, asà como el pasto Taiwán tuvieron el contenido mayor de ácido α-linolénico. Las semillas de germinado de maÃz 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 podrÃa modificar las proporciones de ácido grasos en la leche y la carne con el propósito de incrementar los PUFA, especÃficamente el ácido ruménico asà como el ácido vaccénico.
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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)
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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)
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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)
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Directory of Open Access Journals (Sweden)
Fabrício Augusto Hansel
2008-02-01
Full Text Available Este trabalho foi realizado com o objetivo de avaliar a distribuição de lipídios em sedimentos arqueológicos do sítio Rio do Meio, Ilha de Santa Catarina. Nos extratos totais de lipídios, analisados por cromatografia gasosa e espectrometria de massas (CG e CG-EM, predominaram os compostos ácidos e álcoois saturados. Foram detectados pelo menos dois tipos de matéria orgânica: uma antiga e outra comparativamente recente. Na primeira, o extrato total de lipídios foi dominado por ácidos graxos de cadeias curtas ( Ac20:0 e Al20:0. Em contraste, na deposição classificada como recente, foram identificados em maiores teores os ácidos e álcoois de cadeias longas (> Ac20:0 e Al20:0. Neste estudo, foi possível observar a incorporação de material orgânico procedente de fontes de origem vegetal, bacteriana e, possivelmente, animal (gorduras nos sedimentos arqueológicos analisados.In this study the distribution of lipid compounds was evaluated in sediment samples of an archaeological site Rio do Meio, Santa Catarina Island, Brazil. In the total lipid extracts, analyzed by gas chromatography and mass spectrometry (GC and GC-MS, saturated fatty acids and alcohols were predominant. At least two sources of organic matter were detected, an older and a more recent one. In the old deposit, the most abundant lipids were short-chain fatty acids ( Ac20:0 and Al20:0. In contrast, the fresh deposit was dominated by long-chain fatty acids and alcohols (> Ac20:0 and Al20:0. This paper described the incorporation of vegetal, bacterial and possible animal (fat sources into the archaeological sediments analyzed.
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Directory of Open Access Journals (Sweden)
León, Blanca Liliana Torres
2008-01-01
Full Text Available Objetivo: Avaliar o monômero residual liberado de materiais resilientes para reembasamento polimerizados por diferentes métodos. Metodologia: Dois materiais foram testados: Ever-Soft polymerizado por banho quente de água ou por energia de microondas, e Light Liner polimerizado quimicamente e por luz visível (polimerização dual. O monômero residual liberado foi mensurado em 12 espécimes (40x10x0,3mm fabricados com cada material e método de polimerização. Os espécimes foram armazenados em água destilada por 168 horas a 37ºC, e analisados diariamente por espectrometria ultravioleta (Light Liner: 204nm, Ever-Soft: 206nm. Os dados foram analisados por ANOVA de fator único e teste de Bonferroni (a=0,05. O monômero residual liberado em relação ao tempo foi determinado por análise de regressão polinomial. Resultados: O monômero residual liberado em 168 horas do teste (µg/cm2 em espécimes polimerizados por banho de água quente (0,27±0,01µg/cm2 foi significativamente maior (P < 0,05 que em espécimes processados por energia de microondas (0,25±0,02µg/cm2. Ever-Soft mostrou uma redução na liberação de monomer residual com o tempo, tendendo a se estabilizar em 96 horas. Light Liner continuou a liberar monômero com o tempo. Conclusão: Ever-Soft pode ser polimerizado por energia de microondas. Os valores de monômero residual liberado foram baixos, e os níveis de monômero diminuíram com o tempo
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Oxidação de fármacos por cloro e formação de subprodutos em amostras aquosas em escala de bancada
Directory of Open Access Journals (Sweden)
Brígida P. de Souza
Full Text Available RESUMO Fármacos e desreguladores endócrinos são encontrados em águas naturais brasileiras, incluindo alguns mananciais de abastecimento, também em função da baixa cobertura de coleta e tratamento de esgotos no Brasil. Nesse cenário, o presente trabalho intentou avaliar a remoção de três fármacos - sulfametoxazol (SMX, diclofenaco (DCF e 17β-estradiol (E2 - em água destilada por meio da oxidação com cloro (hipoclorito de sódio, variando-se a dose de cloro e o tempo de contato em ensaios de batelada. As soluções cloradas foram analisadas, ainda, por cromatografia acoplada à espectrometria de massas para identificação de eventuais subprodutos de oxidação. Para tempo de contato de 10 min e dose de cloro de 1,5 mg.L-1, foi observada remoção média de 61% para DCF, 36% para E2 e 33% para SMX. Apenas para o DCF verificou-se diferença estatisticamente significativa (α=0,05 para dose de cloro de 3,0 mg.L-1. A oxidação seguiu modelo cinético de pseudossegunda ordem, com valores de k2 de 0,0168 L.µg.min-1 para SMX (para ambas doses testadas, de 0,0133 e 0,0798 L.µg.min-1 para DCF, e de 0,0326 e 0,0289 L.µg.min-1 para E2, para doses de cloro de 1,5 e 3,0 mg.L-1, respectivamente. Por fim, verificou-se que o aumento do tempo de contato favoreceu a oxidação dos fármacos, ainda que com a perspectiva de formação de subprodutos para SMX e E2.
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Directory of Open Access Journals (Sweden)
Sansonetti, A.
2006-06-01
Full Text Available St. Abbondio, at Como, Italy, is one of the most outstandingRomanesque basilicas in Northern Italy. Theentire building, and particularly the cloister, has beenthe object of a number of restorations over the centuries,as well as a significant conservation endeavourconducted between 2000 and 2003. In the in-depthdiagnostic survey undertaken on that occasion, thecomposition and morphology of the plaster in bothinteriors and exteriors were determined to obtain furtherinsight into the history of the cloister and its conservation.Plaster representative of the various phasesof construction were characterized with techniquessuch as powder X-ray diffraction, mercury intrusionporosimetry, thin section optical microscopy and atomicspectrometry. As a result of these analyses, groupsof samples with similar characteristics could be identified,confirming historiographic hypotheses on thesequence of the restoration and conservation workdone on the building and establishing a possible toolfor architectural archaeology.S. Abbondio (Como, Italia es una de las mas extraordinariasbasilicas romanicas presentes en el norte de Italia.El edificio entero y en particular el claustro ha sido expuestoa varias intervenciones durante los ultimos siglos, enparticular los ultimos trabajos de conservacion ejecutadosentre los anos 2000 y 2003. En esta ocasion se ha efectuadouna vasta campana diagnostica sobre los revoquestanto internos como externos, destinada a clasificarlosdesde el punto de vista compositivo-morfologico y paradescubrir la historia sobre la conservacion del claustro.Revoques representativos de las diferentes fases constructivashan sido identificados con la utilizacion de metodoscomo el analisis de difraccion de rayos X en polvo,porosimetria por intrusion de mercurio, microscopia opticapara secciones finas y espectrometria atomica. Losresultados han permitido agrupar las muestras que presentabancaracteristicas similares, confirmando hipotesishistoricas sobre la
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Directory of Open Access Journals (Sweden)
Daniel Augusto Schurt
Full Text Available Este trabalho teve como objetivo elucidar, por meio da pirólise analítica acoplada à cromatografia gasosa e espectrometria de massa, alterações na composição química da lignina nas bainhas de plantas de arroz das cultivares BR-Irga 409 e Labelle supridas ou não com silício (Si e infectadas por Rhizoctonia solani. A concentração de Si nas bainhas das plantas supridas com esse elemento foi significativamente maior (2,7 dag kg-1 em comparação com as plantas não supridas (0,45 dag kg-1. Na presença de Si, a área abaixo da curva do progresso da queima das bainhas foi significativamente reduzida em 19 e 25%, respectivamente, para as plantas das cultivares BR-Irga-409 e Labelle em relação à ausência desse elemento na solução nutritiva. Com base nos espectros de massas obtidos, foram identificados 33 compostos, dos quais 10 foram produtos da degradação de carboidratos e 23 derivados da lignina. Dentre os derivados da lignina, oito compostos eram do tipo p-hidroxifenila, 11 compostos do tipo guaiacila e quatro compostos do tipo siringila. Nas bainhas das plantas das duas cultivares de arroz, supridas ou não com Si, a concentração de lignina (p-hidroxifenila, siringila (S e guaiacila (G foi de, aproximadamente, 15%. Houve aumento na relação S/G apenas nas bainhas das plantas da cultivar BR-Irga 409 supridas com Si e infectadas por R. solani. A maior concentração de Si nas bainhas das plantas de arroz das duas cultivares, que por sua vez resultou em aumento na relação S/G, contribuiu para reduzir os sintomas da queima das bainhas.
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Directory of Open Access Journals (Sweden)
E'Gues, Miguel Antônio Menezes
2008-01-01
Full Text Available Objetivo: Este trabalho teve por objetivo preparar e caracterizar um novo compósito de colágeno com silicato e hidroxiapatita que possa vir a ser utilizado como material endodôntico em capeamento pulpar direto e em pulpotomia. Metodologia: Os materiais utilizados como matéria-prima foram colágeno do tipo I na forma aniônica, silicato (cimento Portland Branco e hidroxiapatita sintetizada. Estes materiais foram misturados em proporções variadas de modo a obter um material compósito na forma de pasta. Os materiais obtidos foram caracterizados por técnicas de calorimetria exploratória diferencial, termogravimetria, microscopia eletrônica de varredura (MEV, espectrometria de dispersão de energia de Raios-X e espectroscopia na região do infravermelho. Resultados: A presença de colágeno no compósito foi demonstrada por transições térmicas típicas daquelas encontradas para o colágeno do tipo I (~48ºC, independentemente da proporção utilizada, e também por imagens de MEV, onde as fibras colagênicas também puderam ser observadas interligando as partículas de silicato. A composição química de todos compósitos de colágeno foi praticamente idêntica à do silicato utilizado. Conclusão: Os resultados mostraram que a estrutura da matriz de colágeno nos compósitos testados não foi alterada. Esta é uma característica importante para a utilização em endodontia do material compósito proposto, objetivando uma reparação tecidual de forma "mais natural"
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Directory of Open Access Journals (Sweden)
Ana Cristina Miranda Senna Gouvêa
2012-03-01
Full Text Available Availability of analytical standards is a critical aspect in developing methods for quantitative analysis of anthocyanins. The anthocyanins cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside were isolated from samples of freeze-dried açaí (Euterpe oleraceae Mart., which is a round and purple well-known palm fruit in Brazil, and then used as standards. The isolation of the anthocyanins was performed by High Performance Liquid Chromatography (HPLC, using an adapted six-channel selection valve. The identification of anthocyanin pigments in açaí was based on mass spectrometric data for molecular ions and MS-MS product ions and on previous published data. After the collection procedure, standards with a high purity grade were obtained and an external standard curve of each anthocyanin was plotted.Disponibilidade de padrões analíticos é um aspecto crítico no desenvolvimento de métodos de análises quantitativas de antocianinas. Para a obtenção dos padrões isolados de antocianinas cianidina-3-O-glicosídeo e cianidina-3-O-rutinosídeo foram utilizadas amostras liofilizadas de açaí (Euterpe oleraceae Mart., que é um conhecido fruto de palmeiras no Brasil de forma arredondada e roxo. O isolamento das antocianinas foi realizado por Cromatografia Líquida de Alta Eficiência (CLAE, utilizando uma válvula seletora de seis canais. A identificação de antocianinas no açaí foi baseada em dados publicados na literatura e por espectrometria de massas. Após a coleta, padrões com um alto grau de pureza foram obtidos e uma curva para padronização externa de cada antocianina foi feita.
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Directory of Open Access Journals (Sweden)
Heloísa Helena Garcia da Silva
2007-06-01
Full Text Available Oil-resin fractions from Copaifera reticulata Ducke (Leguminosae-Caesalpinoideae were evaluated for larvicidal activity on third larval instars of Aedes aegypti, in searching for alternative control methods for this mosquito. The bioactive fractions were chemically monitored by thin-layer chromatography, ¹H and 13C nuclear magnetic resonance and mass spectrometry. Bioassays were performed using five repetitions, at a temperature of 28 ± 1°C, relative humidity of 80 ± 5% and light and dark cycles of 12h. Mortality was indicated by darkening of the cephalic capsule after 24h of exposure of the larvae to the solutions. The most active fractions were CRM1-4 (sesquiterpenes and CRM5-7 (labdane diterpenes, which showed LC50 values of 0.2 and 0.8ppm, respectively.A atividade larvicida das frações do óleo-resina de Copaifera reticulata Ducke (Leguminosae-Caesalpinoideae foi avaliada em larvas de 3º estádio de Aedes aegypti, na busca de alternativas para o controle desse mosquito. As frações bioativas foram monitoradas quimicamente através de cromatografia de camada delgada, analisada por ressonância magnética nuclear de hidrogênio (¹H e 13C e espectrometria de massas. Os bioensaios foram realizados à temperatura de 28±1°C, 80±5% de umidade relativa e fotofase de 12h, com cinco repetições. A mortalidade foi determinada através do escurecimento da cápsula cefálica, após 24h de exposição das larvas às soluções. As frações mais ativas foram CRM1-4 (sesquiterpenos e CRM5-7 (diterpeno labdano, que mostraram os valores de CL50 de 0,2 e 0,8ppm, respectivamente.
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Study of reproducibility of measurements with the spectrometer of Bonner multispheres
International Nuclear Information System (INIS)
Azevedo, G.A.; Pereira, W.W.; Patrao, K.C.S.; Fonseca, E.S.
2013-01-01
This work aims to study the metrological behavior of the Bonner Multisphere Spectrometer (BMS) of the LN / LNMRI / IRD - Laboratorio Metrologia de Neutrons / Laboratorio Nacional de Metrologia e Radiacao Ionizante / Instituto de Radioprotecao e Dosimetria, for measurements in repeatability and reproducibility conditions. Initially, a simulation was done by applying the Monte Carlo method, using the MCNP code and respecting the ISO 8529-1 (2001), using the sources of Californium ( 252 Cf), Americium-Beryllium ( 241 AmBe) and californium in heavy water (Cf + D 2 O), all located at a distance of 100 cm from the neutron detector ( 6 Li (Eu) - crystal scintillator). In this program, the counting of neutrons that are captured by the detector was made. The source is located in the center of a sphere of radius 300 cm. Analyzes the impact of these neutrons in a point of the sphere wall, which in this case acted as a neutron detector and from there, it is estimated the number of neutrons that collide in the whole sphere. The purpose is to obtain the neutron count for different energy bands in a solid field of neutrons, since they have a spectrum ranging from a low to a high energy that can also vary within a particular environment. Wishes to obtain new fields with different sources and moderators materials to be used as new reference fields. Measurements are being conducted for these fields, with the aim of analyzing the variability conditions of the measurement (repeatability and reproducibility) in LEN - Laboratorio de Espectrometria de Neutrons of the LN/LMNRI/IRD. Thus, the spectrometer will be used to improve both the knowledge of the spectrum as the standard of neutrons of the lab, proving that a spectrometry is essential for correct measurement
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Directory of Open Access Journals (Sweden)
Maíra Lopes Mazoto
2014-12-01
Full Text Available Objetivos: descrever os níveis de exposição ambiental ao chumbo entre criancas de duas escolas localizadas em regiões com características socioambientais distintas no município do Rio de Janeiro. Métodos: estudo piloto em amostra de conveniência com 270 estudantes. A análise das amostras de sangue capilar foi realizada usando o método de Espectrometria de Massa Acoplado a Plasma Indutivo (ICP-MS. A exposição ao chumbo entre as crianças foi estimada através de comportamentos e habitos diarios e presença de fontes de chumbo no domicilio ou entorno. Resultados: a concentração média do chumbo no sangue capilar foi 3,59 μg/dL ± 2,25. Cinco crianças (1,85% apresentaram concentrações acima de 10 μg/dL. Observou-se uma diferença estatisticamente significativa na concentração média de chumbo em sangue capilar nas variáveis idade (p=0,034, renda per capita (p=0,005 e exposição a chumbo (p=0,044. As variáveis renda média familiar per capita e idade mostraram-se inversamente proporcionais à concentração de chumbo e o status de exposição diretamente proporcional. As escolas apresentaram diferença estatisticamente significativa (p=0,004 quanto à prevalência de crianças expostas ao chumbo. Conclusões: embora a variável escola não tenha sido boa preditora da concentração capilar de chumbo, a maior prevalência de crianças expostas a chumbo se encontra na escola localizada na área mais poluída.
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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)
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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)
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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)
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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.
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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.
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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
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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.
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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, ...
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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)
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Directory of Open Access Journals (Sweden)
R.T. Macêdo Santos
1989-08-01
Full Text Available Acredita-se que as lesões teciduais na leptospirose possam decorrer da ação direta das leptospiras, de toxinas sintetizadas ou liberadas durante sua lise. O presente estudo visou a extração quimica da glicolipoproteína (GLP da leptospira, a produção de anti-soro anti-GLP e a avaliação de sua distribuição em cortes de fígado e rim de cobaias inoculadas e sacrificadas em estudo seqüencial diário até o 6°dia de infecção, correspondente ao pico da doença. Procurou-se também correlacionar a expressão tecidual da GLP com o grau de lesões locais, em busca de novos subsídios para a compreensão da patogenia da leptospirose. A QLP foi detectada em fígado e rim de 2 dentre 6 cobaias no 5°dia e em todas as 6 no 6° dia de infecção, sob a forma de grânulos no citoplasma de macrófagos, livres no interstício ou acolados à membrana de células endoteliais e parenquimatosas, especialmente nas regiões mais lesadas. A cronologia do aparecimento da GLP e sua distribuição sugerem tratar-se de produto dc lise de leptospiras fagocitadas por macrófagos e que esta substância, conquanto não comprovada como iniciadora das lesões, associa-se a seu agravamento nas etapas mais avançadas da leptospirose.
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Energy Technology Data Exchange (ETDEWEB)
Miranda Herrera, Carlos A.; Canchola Felix, Ismael; Raygoza Flores, Joaquin; Mora Perez, Othon [Comision Federal de Electricidad, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: carlos.miranda02@cfe.gob.mx
2009-07-15
In the area called Poligono Hidalgo, inside the Cerro Prieto IV zone in the Cerro Prieto geothermal field, BC, corrosion has occurred in the last few years on well casings and pipelines used for geothermal fluids. Corrosion test results are presented here for pipes, type API L-80 and ASTM A-53 grade B, which were subjected to condensate from wells 403 and 424. These wells have thrown corroded material from their respective casings. With these data we pinpoint corrosive conditions in this field area and determine which pipes are adequate to case wells in similar chemical, production conditions to minimize adverse effects and extend the life of the well, allowing more efficient exploitation of the deepest production zones in the reservoir. [Spanish] En el campo geotermico de Cerro Prieto, BC, dentro del area del Poligono Hidalgo en el sector conocido como Cerro Prieto IV, algunos pozos han presentado en los ultimos anos desgastes en sus tuberias de revestimiento y en las tuberias de linea para el transporte del fluido geotermico. Se presentan resultados de pruebas de corrosion con tuberias tipo API L-80 y ASTM A-53 grado B al ser sometidas al condensado de los pozos 403 y 424, los cuales han estado arrojando material de sus respectivas tuberias de revestimiento. Con estos datos se pretende conocer las condiciones corrosivas de esa zona del campo y determinar cual seria la tuberia ideal a utilizar en pozos con condiciones quimicas de produccion semejantes a fin de minimizar este efecto adverso y prolongar la vida de los pozos, a la vez que se permita la explotacion eficiente de las zonas productoras mas profundas del yacimiento.
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Estudio comparativo de la mineralogía y los coloides arcillosos en suelos de trópicos húmedos
Directory of Open Access Journals (Sweden)
Juan Bullón Ames
2014-12-01
Full Text Available Objetivos: Comparar las diferencias de la composición mineralógica de los suelos de Malasia y Zaire con suelos del Perú, en relación al tipo de coloides arcillosos que poseen. Métodos: Se utilizó el método analítico descriptivo correlacional, siendo las variables: a Tipo de arcillas, b Propiedades físicas del suelo y c Propiedades químicas. Se operacionalizó las variables siendo sus indicadores: Para tipo de arcillas: kaolinitas, halloysitas, Illitas, cloritas y esmectitas; para Propiedades físicas, textura: arena, limo y arcilla; para propiedades químicas: pH, aluminio cambiable, acidez cambiable KCl, acidez cambiable BaCl2 TEA. Para determinar estos indicadores se utilizaron los métodos analíticos siguientes: Termodiferencial y Microscopia electrónica para el tipo de arcillas y los minerales goetita y gibsita. Las propiedades físico-quimicas fueron determinadas por los siguientes métodos: La Granulometría (textura por el método Bouyoucos, pH por potenciometría, el aluminio cambiable por titulación del extracto con KCl, acidez cambiable KCl por el método Yuan, y acidez cambiable BaCl2 TEA por Cloruro de bario. Resultados: Se encontró que los Oxisoles están compuestos por arcillas Kaolinitas y por los minerales: Gibsita y Goetita, mientras que los Ultisoles están conformados por arcillas Illiticas, complejos expandibles esmectíticos, en menor proporción por Kaolinitas. Conclusión: Los Ultisoles presentes en Perú son más fértiles que los Oxisoles.
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Aulas-laboratorios de bajo costo, usando TIC
Directory of Open Access Journals (Sweden)
Silvia E. Calderón
2015-01-01
Full Text Available En este trabajo se presentan los resultados de una propuesta educativa orientada a promover el desarrollo de un pensamiento critico y un mayor interes por las ciencias experimentales. Con este fin desarrollamos propuestas de proyectos educativos susceptibles de ser destinadas a las aulas y laboratorios de las escuelas secundarias y primeros anos de la universidad, que resaltan los aspectos metodologicos de las ciencias. Aqui, realizamos una compilacion de varios proyectos, que ilustran formas de incorporar las tecnologias de la informacion y la comunicacion (TIC en diversos experimentos de ciencias, muchos de ellos publicados individualmente anteriormente, y que en conjunto se pueden utilizar para implementar un aula-laboratorio de bajo costo. Con TIC hacemos referencia a la convergencia de computadoras, sistemas audiovisuales, Internet, telefonia, y diversos equipos que se integran con algunos de ellos. Los proyectos intentan integrar areas como fisica, matematica, quimica, informatica, arte, etc. y apuntan a que los estudiantes puedan responder a las preguntas: .Como sabemos esto?, .Por que creemos en aquello? Preguntas que ilustran la naturaleza del pensamiento cientifico. Nuestra contribucion mas significativa es haber desarrollado ≪aulas-laboratorios≫ de muy bajo costo, usando TIC. Con el advenimiento de programas como ≪Una Laptop por Nino≫ que se estan implementando en varios paises de Latinoamerica, resulta oportuno utilizar este recurso como base para generar laboratorios de bajo costo, que creemos pueden ser una herramienta util para mejorar el aprendizaje de las ciencias, incentivar vocaciones y contribuir a desarrollar un pensamiento critico, a la par de desarrollar habilidades con el uso de las TIC que pueden ser de utilidad en diversos ambitos academicos y laborales.
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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)
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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.
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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)
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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.
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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)
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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.
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Evaluation of thermochemical biomass conversion in fluidized bed =
Neves, Daniel dos Santos Felix das
Dado o aumento acelerado dos precos dos combustiveis fosseis e as incertezas quanto a sua disponibilidade futura, tem surgido um novo interesse nas tecnologias da biomassa aplicadas a producao de calor, eletricidade ou combustiveis sinteticos. Nao obstante, para a conversao termoquimica de uma particula de biomassa solida concorrem fenomenos bastante complexos que levam, em primeiro lugar, a secagem do combustivel, depois a pirolise e finalmente a combustao ou gasificacao propriamente ditas. Uma descricao relativamente incompleta de alguns desses estagios de conversao constitui ainda um obstaculo ao desenvolvimento das tecnologias que importa ultrapassar. Em particular, a presenca de elevados conteudos de materia volatil na biomassa poe em evidencia o interesse pratico do estudo da pirolise. A importância da pirolise durante a combustao de biomassa foi evidenciada neste trabalho atraves de ensaios realizados num reator piloto de leito fluidizado borbulhante. Verificou-se que o processo ocorre em grande parte a superficie do leito com chamas de difusao devido a libertacao de volateis, o que dificulta o controlo da temperatura do reator acima do leito. No caso da gasificacao de biomassa a pirolise pode inclusivamente determinar a eficiencia quimica do processo. Isso foi mostrado neste trabalho durante ensaios de gasificacao num reator de leito fluidizado de 2MWth, onde um novo metodo de medicao permitiu fechar o balanco de massa ao gasificador e monitorizar o grau de conversao da biomassa. A partir destes resultados tornou-se clara a necessidade de descrever adequadamente a pirolise de biomassa com vista ao projeto e controlo dos processos. Em aplicacoes de engenharia ha particular interesse na estequiometria e propriedades dos principais produtos piroliticos. Neste trabalho procurou-se responder a esta necessidade, inicialmente atraves da estruturacao de dados bibliograficos sobre rendimentos de carbonizado, liquidos piroliticos e gases, assim como composicoes
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Energy Technology Data Exchange (ETDEWEB)
Tello Hinojosa, Enrique [Gerencia de Proyectos Geotermoelectricos de la Comision Federal de Electricidad, Morelia (Mexico)
1996-05-01
Isotopic and chemical analysis o water produced by 14 springs in the San Antonio El Bravo, Chihuahua, Mexico geothermal area, were carried out in order to establish the geochemical characteristics of the groundwater and to know their interaction with deeper geothermal fluids. We made two samplings of water and gases in 1984 and 1995. The chemical composition of waters produced by the springs in of sodium-bicarbonate-chloride type. It was found, according to the Na:K:Mg relative content, that most hot springs are located in the partial equilibrium zone, whereas the lowest temperature hot springs shift toward the groundwaters domain. The temperature estimated from gas geothermometry was 129 degrees celsius. The isotopic composition at Ojo Caliente and Infiernito springs presents enrichment in {delta}{sup 18}O, product rock-water interaction at high temperature. The Agua Roque spring is located in the line of meteoric waters. Analysis of metals was carried out too, the concentration of gold element is 0.09 mg/l in Ojo Caliente and Infiernito springs, whereas silver, aluminum and iron elements were not detected. The water quality of the springs for agricultural use, is classified between C2-S1, C3-S1, C3- S2, C4-S3 and C4-S4 types, that suggests that only the water from Agua Roque can be used for irrigation. The arsenic element was not detected but the concentration of the boron element is high for irrigation use (2.39 ppm). [Espanol] Los analisis quimicos e isotopicos de agua de 14 manantiales de la zona de San Antonio El Bravo. Chihuahua, Mexico, fueron realizados con el fin de conocer las caracteristicas geoquimicas del acuifero somero y su interaccion con fluidos geotermicos. Se realizaron 2 muestreos tanto de agua como de gases en 1984 y 1995. En ambos muestreos se encontro que la composicion quimica del agua de todos los manantiales es del tipo bicarbonatado-clorurado-sodico. De acuerdo con el contenido relativo de Na:K:Mg el agua de los manantiales mas calientes
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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)
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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)
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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...
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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)
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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)
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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
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Energy Technology Data Exchange (ETDEWEB)
Sheinbaum, C. [UNAM, Mexico, D. F. (Mexico); Jauregui, I. [CONAE, Mexico, D. F. (Mexico)
1995-12-31
This paper presents an analysis of the trends of the energy use for the industry in Mexico. For the various industrial branches (mining, construction, chemical, sugar, cement, paper and cellulose and glass) the changes in energy intensity (measured as the use of the energy divided by the aggregated value) and in the participation of the same in the industrial Internal Gross Product are presented. This is developed by means of the analysis of Laspeyress exchange indexes. It is found that in most of the industrial branches a reduction of the energy density has been originated. The reasons for the falling of this indicator are structural and of technological change nature, depending on the industrial branch. Nevertheless the classical analysis of the Laspeyress indexes is not sufficient to explain the changes occurred in the energy intensity in the Mexican industry for the last years. [Espanol] Este articulo presenta un analisis de las tendencias del uso de la energia para la industria en Mexico. Para las diversas ramas industriales (mineria, construccion, quimica, azucar, cemento, papel y celulosa y vidrio) se presentan los cambios en la intensidad energetica (medida como uso de la energia entre valor agregado) y en la participacion de las mismas en el Producto Interno Bruto (PIB) industrial. Esto se desarrolla por medio del analisis de indices de cambio de Laspeyress. Se encuentra que en la mayoria de las ramas industriales hubo una disminucion en la intensidad energetica. Las razones de la caida de este indicador son estructurales y de cambio tecnologico dependiendo de la rama industrial. Sin embargo el analisis clasico de los indices de Laspeyress es insuficiente para explicar los cambios ocurridos en la intensidad energetica de la industria mexicana para los ultimos anos.
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Energy Technology Data Exchange (ETDEWEB)
Sheinbaum, C [UNAM, Mexico, D. F. (Mexico); Jauregui, I [CONAE, Mexico, D. F. (Mexico)
1996-12-31
This paper presents an analysis of the trends of the energy use for the industry in Mexico. For the various industrial branches (mining, construction, chemical, sugar, cement, paper and cellulose and glass) the changes in energy intensity (measured as the use of the energy divided by the aggregated value) and in the participation of the same in the industrial Internal Gross Product are presented. This is developed by means of the analysis of Laspeyress exchange indexes. It is found that in most of the industrial branches a reduction of the energy density has been originated. The reasons for the falling of this indicator are structural and of technological change nature, depending on the industrial branch. Nevertheless the classical analysis of the Laspeyress indexes is not sufficient to explain the changes occurred in the energy intensity in the Mexican industry for the last years. [Espanol] Este articulo presenta un analisis de las tendencias del uso de la energia para la industria en Mexico. Para las diversas ramas industriales (mineria, construccion, quimica, azucar, cemento, papel y celulosa y vidrio) se presentan los cambios en la intensidad energetica (medida como uso de la energia entre valor agregado) y en la participacion de las mismas en el Producto Interno Bruto (PIB) industrial. Esto se desarrolla por medio del analisis de indices de cambio de Laspeyress. Se encuentra que en la mayoria de las ramas industriales hubo una disminucion en la intensidad energetica. Las razones de la caida de este indicador son estructurales y de cambio tecnologico dependiendo de la rama industrial. Sin embargo el analisis clasico de los indices de Laspeyress es insuficiente para explicar los cambios ocurridos en la intensidad energetica de la industria mexicana para los ultimos anos.
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Método complexométrico para el análisis rápido del cemento portland
Directory of Open Access Journals (Sweden)
Calleja, J.
1964-06-01
Full Text Available Not availableSe aborda en este trabajo el problema del análisis rápido del cemento y de los materiales silíceos por medios puramente químicos y sin la ayuda que pudieran prestar otras técnicas físicas. Se adopta un método volumétrico casi general, basado en la .complexometría, sin más excepción que la determinación gravimétrica acelerada de la sílice. Para la determinación del óxido férrico se mantiene el procedimiento dicromatométrico por su sencillez y precisión. Por complexometría se determinan con Complexona III 0,01 M la suma de alúmina y ácido férrico (la alúmina se calcula por diferencia, la suma de cal y magnesia y, aparte, la cal (la magnesia se calcula por diferencia y el trióxido de azufre. El método se manifiesta tan preciso y reproducible como los clásicos l (dentro de las tolerancias de las Normas A. S. T. M. y es mucho más rápido, puesto que permite efectuar el análisis completo del cemento en unas tres horas. Es también más sencillo, ya que ahorra pesadas y calcificaciones (gravimetrías y no requiere el empleo de equipos especiales de colorimetría, fotometría, espectrometría de rayos X, si bien se conjuga bien con cualquiera de estas técnicas de naturaleza física. Es susceptible de sucesivas mejoras, y en tal sentido se continúa trabajando en el Departamento de Quimica del I.E.T.c.c.
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La ingeniería de procesos químicos: una visión alternativa del programa de Ingeniería Química
Directory of Open Access Journals (Sweden)
Alfonso Conde Cotes
1996-01-01
Full Text Available El Ingeniero de Procesos ha sido definido como aquel que tiene la responsabilidad de crear sistemas de procesamiento de la materia que, en forma económica, segura y sin alteración perjudicial del ambiente, transformen materias primas, energía y conocimiento en productos de utilidad. Su labor se centra en el análisis y la sintesis de procesos, para lo cual desarrolla labores de descomposición, modelación y simulación (análisis, y de diseño, evaluación, optimización y control (síntesis según se trate de un proceso dado o de su gestación. El proceso es un sistema conformado por elementos (equipos y sus relaciones fisicas controlantes, que interactúa sobre el medio externo recibiendo de él impulsos en forma de materias primas y energía y devuelve productos útiles para el hombre. El proceso es creado y operado por el hombre para su beneficio. Por el objeto de su trabajo, la ingeniería de procesos constituye el enfoque, dentro de la ingeniería quimica, que más cercanamente puede desarrollar la función central definida para la universidad. No se niega la posibilidad del desempeño del profesional en otras funciones que también le son propias, pero la tesis que se formula habla de que una formación como la hasta ahora esbozada, referida a la globalidad de los procesos y que integra los elementos del saber normalmente asociados a la carrera, aventaja los requerimientos del ejercicio profesional medio, es decir, no desatiende el campo de trabajo, y permite formar individuos capaces de transformar. La discusión tiene qué ver con el contenido curricular de la carrera y con la metodología de su desarrollo.
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Energy Technology Data Exchange (ETDEWEB)
Garcia Arelle, Carlos [Turbomaquinas S. A. de C.V., La Piedad, Michoacan (Mexico)
2007-11-15
The continuous use of steam turbines, the chemistry of the steam itself and the variations of operation velocities, cause the gradual deterioration by erosion, oxidation and/or corrosion of the rotors and blades. When this happens most of the original manufacturers recommend to rectify the areas, diminishing the surfaces, or to compare with a new rotor. TURBOMAQUINARIAS S.A. de C.V. has developed the most reliable and safe methods to return the rotor to its original dimensions and in case of recurrent problems such as erosion, oxidation and/or wear, it offers the alternative of attaching coatings metallurgically compatible with which these problems are eliminated or diminished that might show up on the rotor surface as well as in the body of the discs or of the blades. These restoring methods are recommended by the international standards such as API 687. [Spanish] El uso continuo de las turbinas de vapor, la quimica del mismo vapor y la variacion de las velocidades de operacion, ocasionan el deterioro gradual por erosion, oxidacion y/o corrosion de los rotores y de los alabes. Al ocurrir esto la mayoria de los fabricantes originales recomiendan rectificar las areas, disminuyendo las superficies, o bien comparar un rotor nuevo. TURBOMAQUINARIAS S.A. de C.V. ha desarrollado los metodos mas confiables y seguros para devolver a su rotor las dimensiones originales y en caso de problemas recurrentes tales como erosion, oxidacion y/o desgaste, ofrece la alternativa de agregar recubrimientos metalurgicamente compatibles con los cuales se eliminan o se disminuyen estos problemas que pueden presentarse tanto en la superficie del rotor como del cuerpo de los discos o bien de los alabes. Estos metodos de restauracion son recomendados por las normas internacionales tales como la API 687.
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Directory of Open Access Journals (Sweden)
Garcia Campoy AH
2018-05-01
Full Text Available Abraham Heriberto Garcia Campoy,1 Rosa Martha Perez Gutierrez,1 Gabriela Manriquez-Alvirde,2 Alethia Muñiz Ramirez3 1Laboratorio de Investigación de Productos Naturales, Escuela Superior de Ingenieria Quimica e Industrias extractivas IPN, Unidad Profesional Adolfo Lopez Mateos, Mexico City, Mexico; 2Universidad Autonoma Metropolitana, Mexico City, Mexico; 3CONACYT-IPICYT/CIIDZA, San Luis Potosí, México Background: The aim was to explore the efficacy of extract of Eysenhardtia polystachya-loaded silver nanoparticles (EP/AgNPs on pancreatic β cells, INS-1 cells, and zebrafish as a valuable model for the study of diabetes mellitus.Materials and methods: EP/AgNPs were synthesized using methanol/water bark extract of E. polystachya and characterized using various physicochemical techniques.Results: Immersion of adult zebrafish in 111 mM glucose solution resulted in a sustained hyperglycemic, hyperlipidemic state, and serum insulin levels decreased. The synthesized EP/AgNPs showed an absorption peak at 413 nm on ultraviolet–visible spectroscopy, revealing the surface plasmon resonance of the nanoparticles. Transmission electron microscopy indicated that most of the particles were spherical, with a diameter of 10–12 nm, a polydispersity index of 0.197, and a zeta potential of -32.25 mV, suggesting high stability of the nanoparticles. EP/AgNPs promote pancreatic β-cell survival, insulin secretion, enhanced hyperglycemia, and hyperlipidemia in glucose-induced diabetic zebrafish. EP/AgNPs also showed protection of the pancreatic β-cell line INS-1 against hydrogen peroxide-induced oxidative injury.Conclusion: The results indicate that EP/AgNPs have good antidiabetic activity and therefore could be used to prevent the development of diabetes. Keywords: Eysenhardtia polystachya, zebrafish, silver nanoparticles, diabetes, insulin, hyperlipidemia
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Bismuth oxide aqueous colloidal nanoparticles inhibit Candida albicans growth and biofilm formation
Directory of Open Access Journals (Sweden)
Hernandez-Delgadillo R
2013-04-01
Full Text Available Rene Hernandez-Delgadillo,1 Donaji Velasco-Arias,3 Juan Jose Martinez-Sanmiguel,2 David Diaz,3 Inti Zumeta-Dube,3 Katiushka Arevalo-Niño,1 Claudio Cabral-Romero2 1Facultad de Ciencias Biológicas, Instituto de Biotecnologia, Universidad Autonoma de Nuevo Leon, UANL, Monterrey, Mexico; 2Facultad de Odontología, Universidad Autonoma de Nuevo Leon, UANL, Monterrey, México; 3Facultad de Quimica, Universidad Nacional Autonoma de Mexico, UNAM, Distrito Federal, México Abstract: Multiresistance among microorganisms to common antimicrobials has become one of the most significant concerns in modern medicine. Nanomaterials are a new alternative to successfully treat the multiresistant microorganisms. Nanostructured materials are used in many fields, including biological sciences and medicine. Recently, it was demonstrated that the bactericidal activity of zero-valent bismuth colloidal nanoparticles inhibited the growth of Streptococcus mutans; however the antimycotic potential of bismuth nanostructured derivatives has not yet been studied. The main objective of this investigation was to analyze the fungicidal activity of bismuth oxide nanoparticles against Candida albicans, and their antibiofilm capabilities. Our results showed that aqueous colloidal bismuth oxide nanoparticles displayed antimicrobial activity against C. albicans growth (reducing colony size by 85% and a complete inhibition of biofilm formation. These results are better than those obtained with chlorhexidine, nystatin, and terbinafine, the most effective oral antiseptic and commercial antifungal agents. In this work, we also compared the antimycotic activities of bulk bismuth oxide and bismuth nitrate, the precursor metallic salt. These results suggest that bismuth oxide colloidal nanoparticles could be a very interesting candidate as a fungicidal agent to be incorporated into an oral antiseptic. Additionally, we determined the minimum inhibitory concentration for the synthesized
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Energy Technology Data Exchange (ETDEWEB)
Vazquez-Huerta, G.; Ramos-Sanchez, G. [Cinvestav-IPN, Mexico, D.F. (Mexico)]. E-mail: gervazkez@gmail.com; Antano-Lopez, R. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica S. C., Pedro Escobedo, Queretaro (Mexico); Solorza-Feria, O. [Cinvestav-IPN, Mexico, D.F. (Mexico)
2009-09-15
Nanometric-sized ({approx}5nm) Au particles were synthesized using the chemical reduction of AuCl{sub 3} with NaBH{sub 4}. The Au particles were analyzed with x-ray diffraction (XRD), finding that the particles are highly crystalline, with a face-centered cubic (FCC) structure. The impedance spectrums obtained in 0.5M H{sub 2}SO{sub 4} solution saturated with O{sub 2}, at potentials greater than 0.38 V vs NHE, show one single temperature constant associated with the reduction in O{sub 2} on Au particles, producing hydrogen peroxide (O{sub 2} +2H{sup +} + 2e{sup -} =H{sub 2}O{sub 2}). At potentials less than 0.38 V, a second constant temperature appears associated with a second process, that is, the reduction of H{sub 2}O{sub 2} to H{sub 2}O. [Spanish] Particulas de Au con tamano nanometrico ({approx}5nm) fueron sintetizadas a partir de la reduccion quimica del AuCl{sub 3} con NaBH{sub 4}. Las particulas de Au fueron analizadas con difraccion de rayos X (XRD), se encontro que las particulas son altamente cristalinas, con una estructura cubica centrada en las caras (FCC). Los espectros de impedancia obtenidos en solucion 0.5M H{sub 2}SO{sub 4} saturada con O{sub 2}, a potenciales mayores de 0.38 V vs NHE muestran una sola constante de tiempo, asociada a la reduccion de O{sub 2} sobre las particulas de Au, dando como producto peroxido de hidrogeno (O{sub 2} +2H{sup +} + 2e{sup -} =H{sub 2}O{sub 2}). A potenciales menores de 0.38 V aparece una segunda constante de tiempo, asociada a un segundo proceso, i.e. la reduccion del H{sub 2}O{sub 2} a H{sub 2}O.
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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).
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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.
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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)
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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)
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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.
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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)
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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)
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Miriam Gonçalves Martins Ramos
2007-12-01
Full Text Available Neste trabalho, investigou-se o nível de contaminação por Cd, Cr, Cu, Pb e Zn, nos ambientes de mangues próximos ao Rio Cubatão, utilizando como bioindicador as espécies de plantas A. schaueriana, L. racemosa e R. mangle. As amostras de folhas destas plantas foram coletadas em quatro pontos de amostragem situados fora da área povoada da cidade de Cubatão. O conteúdo de metais pesados nas folhas foi determinado utilizando a técnica de Espectrometria por Absorção Atômica (FAAS. Os resultados obtidos indicam uma contaminação por cádmio e cromo em diversas amostras analisadas neste trabalho. De uma forma geral, as três espécies de plantas apresentaram resultados muito similares tanto no teor como na ordem em que bioacumulam os metais estudados: Zn > Pb > Cr > Cu > Cd. Desta forma, em princípio, qualquer uma delas poderia ser utilizada como bioindicador de poluição ambiental por metais pesados naquela região.In this work, the contamination level by Cd, Cr, Cu, Pb and Zn in mangrove environments near the Cubatão River has been investigated using as bioindicator the plant species A. schaueriana, L. racemosa and R. mangle. Leave samples of these plants were collected in four locals situated out of the populated area of the Cubatão town. The heavy metals content in the leaves were determined by the Flame Atomic Absorption Spectrometry (FAAS technique. The results obtained have shown some contamination by cadmium and cromium for several leave samples analysed in this work. In general, the three species of plants presented similar results concerning the content as well as the bioaccumulation order for the studied metals: Zn > Pb > Cr > Cu > Cd. In this way, any one of them could, in principle, be employed as bioindicator of heavy metal environmental pollution in that region.
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Keila Maria Roncato Duarte
2002-08-01
Full Text Available Com o desenvolvimento da indústria farmacêutica e o conseqüente surgimento de novas substâncias promotoras do crescimento animal, o setor agropecuário necessita de tecnologias cada vez mais eficientes e sensíveis para detectar possíveis resíduos deixados por este vasto número de substâncias anabolizantes, principalmente esteróides com atividades estrogênicas, androgênicas e progestogênicas. Tais substâncias, quando presentes na carne, gordura, ovos, entre outros, podem ser detectadas e quantificadas por uma série de métodos, dentre os quais, descrevemos os cromatográficos, baseados principalmente em cromatografia gasosa acoplada à espectrometria de massa (CG-EM, cromatografia líquida de alta eficiência (CLAE, cromatografia em camada delgada de alta eficiência (CCDAE e os métodos imunológicos, como radioomunoensaio (RIA e ensaio imunoenzimático (ELISA. Estes métodos têm como vantagens o elevado número de amostras que podem ser analisadas por período de tempo, aliadas à alta sensibilidade na detecção de resíduos.With the development of the pharmaceutical industry, and consequently appearance of new substances which promote animal growth, the agricultural sector needs technologies more and more efficient and sensitive to detect possible residues left by this vast number of anabolic substances, mainly steroids with estrogenic, androgenic and progesterogenics activities. Such substances, when present in meat, fat, and eggs among others, can be detected and quantified by a series of methods, among the ones which we described the chromatographic methods, based mainly on gaseous chromatography coupled to the mass espectrometry (CG-MS, high performance liquid chromatography (HPLC, thin layer chromatography (HPTLC and the immunological methods, as radioimmunoassay (RIA and enzyme linked immunosorbent assay (ELISA. These methods have as advantages the high number of samples that can be analyzed by period of time, toghether
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Mário Roberto Maróstica Junior
2008-03-01
Full Text Available Ethanolic extracts and essential oils from Green Propolis from southeastern Brazil and leaf buds from its botanical origin Baccharis dracunculifolia were analyzed by Reversed Phase High Performance Liquid Chromatography (RP-HPLC, Reversed Phase High Performance Thin Layer Chromatography (RP-HPTLC and Gas Chromatography - Mass Spectrometry (GC-MS. The essential oils were obtained by hydro-distillation. Both ethanolic extracts and essential oils showed similar chromatographic profiles. Thirteen flavonoids were identified by RP-HPLC and RP-HPTLC analyses in both samples. Twenty-three volatile compounds were identified by GC-MS analyses. Seventeen were present in both essential oils. The major flavonoid compound in both extracts was artepillin C. The major volatile compound in both essential oils was nerolidol. The major compounds identified in this work could be used as chemical markers in order to classify and identify botanical origins of propolis.Extratos etanólicos e óleos essenciais de própolis verde do sudeste brasileiro e gemas de sua origem botânica (Baccharis dracunculifolia foram analisados por CLAE-FR (Cromatografia Líquida de Alta Eficiência em Fase Reversa, CCDAE (Cromatografia em Camada Delgada de Alta Eficiência e CG-EM (Cromatografia Gasosa acoplada a Espectrometria de Massas. Os óleos essenciais foram obtidos por hidro destilação. Extratos etanólicos e óleos essenciais de Baccharis dracunculifolia e de própolis mostraram perfis cromatográficos similares entre si. Treze flavonóides foram identificados por CLAE-FR e CCDAE em ambas as amostras. Vinte e três compostos voláteis foram identificados por CG EM, sendo dezessete deles presentes em ambos os óleos essenciais. Artepillin C foi o flavonóide encontrado em maiores concentrações em ambas as amostras, enquanto nerolidol foi o volátil majoritário em ambos os óleos essenciais. Os compostos majoritários identificados neste trabalho podem ser utilizados como
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Valdir F. Veiga Junior
2007-01-01
Full Text Available O gênero Copaifera L. é um dos mais importantes economicamente na Região Amazônica devido, principalmente, à produção dos óleos de copaíba, oléo-resinas com diversas propriedades farmacológicas confirmadas. Apesar disso, os estudos fitoquímicos com as sementes das árvores do gênero Copaifera L.são raros. Copaifera officinalis foi a primeira espécie do gênero Copaifera a ser descrita. Este trabalho descreve a composição dos extratos obtidos em hexano e em acetato de etila das sementes de C. officinalis. No extrato obtido em hexano, a análise por cromatografia em fase gasosa utilizando padrões e através de espectrometria de massas permitiu a identificação de: esqualeno, tetradecano, hexadecano, campesterol, estigmasterol e beta-sitosterol; os ácidos graxos hexadecanóico, 9-octadecenóico e octadecanóico (majoritários; e decanóico, eicosanóico, docosanóico e tetracosanóico (minoritários. Cumarina foi isolada do extrato em acetato de etila e identificada por técnicas de RMN.Copaifera L. is one of the most economically important plant genera in the Amazon Region, since it exudes a resin-oil named copaiba oil possessing several confirmed pharmacological properties. In spite of that, phytochemical studies of the seeds from this genus are rare. Copaifera officinalis L. was the first species in the genus Copaifera to be described. This paper describes the chemical composition of the hexane and ethyl acetate extracts of the seeds from this species. In the hexane extract, gas chromatography and mass spectrometry analyses enabled us to identify squalene, tetradecane, hexadecane, campesterol, stigmasterol and beta-sitosterol; hexadecanoic, 9-octadecenoic and octadecanoic acids (major substances; as well as decanoic, eicosanoic, docosanoic and tetracosanoic (minor substances acids. Coumarin was detected in the ethyl acetate extract, isolated and identified by NMR.
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Nogueira A.R. de A.
1997-01-01
Full Text Available Um sistema polivalente de análises químicas por injeção em fluxo foi proposto para a determinação de cálcio, magnésio e fósforo em digeridos ácidos de plantas. O-cresolphtaleina complexona (CPC foi selecionado como reagente colorimétrico para a determinação de cálcio e magnésio e molibdato de amônio/vanadato de amônio para a determinação de fósforo. O sistema empregou tampão amônio-amônia (pH 10,5 e EGTA ou 8-hidroxiquinolina como agentes mascarantes para cálcio ou magnésio, respectivamente. Equações de calibração lineares foram obtidas, sendo que para facilitar a utilização do sistema proposto, foi utilizada curva analítica mista (até 40,0 mg Ca L-1, 10,0 mg Mg L-1 e 16,0 mg P L-1, não sendo observadas interferências entre os elementos. Os limites de detecção foram: 0,10; 0,05 e 0,004 mg L-1 respectivamente para Ca, Mg e P. Pequenas modificações no coeficiente das equações de calibração (normalmente < 3% foram observadas após períodos de 4 h de trabalho. Os resultados apresentaram-se precisos (d.p.r. < 0,02, e em concordância com método alternativo (espectrometria de absorção atômica. Quando o sistema foi aplicado a análises em rotina, boa repetibilidade foi observada, sendo obtidas velocidade de amostragem de 107 amostras h-1 para magnésio e 75 amostras h-1 para cálcio e fósforo, enfatizando a simplicidade, robustez e versatilidade, inerentes aos sistemas de análises por injeção em fluxo.
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Ação e caracterização química de óleos essenciais no manejo da antracnose do maracujá
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César Fernandes Aquino
2012-12-01
Full Text Available Objetivou-se avaliar dois métodos de inoculação de Colletotrichum gloeosporioides em maracujá, testar a patogenicidade de diferentes isolados, o efeito fungitóxico e a composição química dos óleos essenciais das espécies medicinais alecrim-pimenta (Lippia sidoides Cham., capim-santo [Cymbopogon citratus (D. C. Stapf.], alfavaca-cravo (Ocimum gratissimum L., no controle da antracnose [Colletotrichum gloeosporioides (Penz.], associado ao estádio de maturação de frutos de maracujazeiro-amarelo. Avaliaram-se três experimentos, onde se testou a patogenicidade de seis isolados do fungo em delineamento inteiramente casualizado, com seis repetições, outro com o mesmo delineamento em esquema fatorial 2x2 (suspensão de conídios e disco de micélio e frutos (verdes e maduros, com seis repetições. No tratamento com frutos, utilizou-se o delineamento inteiramente casualizado, em esquema fatorial 5x3+1, sendo cinco concentrações (0; 2; 4; 6 e 8µL mL-1 e três espécies medicinais, mais o tebuconazol, com cinco repetições. Fez-se a caracterização química dos óleos por cromatografia gasosa, com espectrometria de massas. Todos os isolados foram patogênicos. Os frutos maduros apresentaram maior diâmetro das lesões, quando inoculados com suspensão de conídios. O óleo de C. citratus proporcionou o menor diâmetro das lesões nos frutos, até a concentração de 6 µL mL-1. Na concentração de 8 µL mL-1, todos os óleos inibiram o desenvolvimento do fungo. O timol (30,24%, o citral (77,74% e o eugenol (92,89% foram componentes majoritários em L. sidoides, C. citratus e O. gratissimum, respectivamente.
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Cleyde Ferreira Barreto Valotto
2011-04-01
Full Text Available INTRODUÇÃO: Dengue é um importante problema de saúde pública, em vários países, e tem como principal vetor o Aedes aegypti, mosquito mais adaptado às áreas urbanizadas. Apresenta-se, pela primeira vez, as alterações ultraestruturais em larvas de 3º estádio, desse mosquito, causadas pelos larvicidas naturais, um diterpeno labdano, extraído de Copaifera reticulata, e uma fração rica em taninos catéquicos, extraída de Magonia pubescens, evidenciando o mecanismo de ação dessas substâncias. MÉTODOS: Os experimentos foram realizados com larvas de 3º estádio em solução de 0,9ppm, do diterpeno (3-β-acetoxylabdan-8(17-13-dien-15-óico e de 3,7ppm, da fração majoritária de tanino catéquico de massa molecular 864Da. Obtiveram-se as substâncias através de fracionamentos cromatográficos sucessivos, identificadas por ressonância magnética nuclear de hidrogênio e espectrometria de massas. As larvas que atingiram estado letárgico foram coletadas e dissecadas e seus tubos digestórios fixados, desidratados, emblocados e polimerizados. Cortes ultrafinos foram feitos e contrastados com acetato de uranila 3% e citrato de chumbo, posteriormente, levados ao microscópio eletrônico. RESULTADOS: As principais alterações ultraestruturais provocadas pelos diterpeno e tanino sobre larvas de Aedes aegypti foram vacuolização citoplasmática, desorganização e degeneração celular, mudança estrutural dos microvilos e deslocamento das células da lâmina basal. CONCLUSÕES: O diterpeno e a fração rica em taninos catéquicos provocaram a morte das larvas de Aedes aegypti através da destruição celular no intestino médio.
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Valores de referência de qualidade para metais pesados em solos do Rio Grande do Norte
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Welka Preston
2014-06-01
Full Text Available O crescimento industrial e o populacional têm aumentado os teores de metais pesados nos solos e impactado a qualidade desse recurso. Nesse contexto, as agências de proteção ambiental vêm despendendo esforços para o estabelecimento de índices que possam identificar áreas suspeitas de contaminação. Valores de Referência de Qualidade para Solos (VRQs refletem a concentração natural de determinada substância no solo, sem interferência antrópica. O trabalho objetivou estabelecer os VRQs para os metais Ag, Ba, Cd, Co, Cr, Cu, Ni, Pb, Sb, V e Zn exigidos pelo Conama, para composição da legislação direcionada ao monitoramento desses elementos nos solos do Estado do Rio Grande do Norte. Foram coletadas 416 amostras de solo em áreas de mata nativa ou com mínima influência antrópica. A abertura das amostras foi efetuada pelo método EPA-3051A, sendo os metais determinados por espectrometria de emissão ótica (ICP-OES e absorção atômica (AA. Os resultados do trabalho comprovaram que estudos regionalizados são essenciais para definição de VRQs. Os VRQs calculados para o Rio Grande do Norte foram mais restritivos que os de outros estados do país. A análise fatorial de confirmação dos dados foi útil para obtenção de VRQs mais confiáveis e demonstrou que para o Estado esses valores podem ser estabelecidos com apenas duas repetições por local de coleta. Nesse sentido, é primordial um planejamento prévio, de distribuição dos locais de amostragem, de maneira que os diversos compartimentos geomorfológicos, pedológicos e geológicos do Estado sejam representados.
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Eula Maria de M. B. Costa
2008-06-01
Full Text Available Microbial biotransformations constitute an important alternative as models for drug metabolism study in mammalians and have been used for the industrial synthesis of chemicals with pharmaceutical purposes. Several microorganisms with unique biotransformation ability have been found by intensive screening and put in commercial applications. Ten isolates of Beauveria sp genus filamentous fungi, isolated from soil in the central Brazil, and Beauveria bassiana ATCC 7159 were evaluated for their capability of quercetin biotransformation. Biotransformation processes were carried out for 24 up to 96 hours and monitored by mass spectrometry analyses of the culture broth. All strains were able to metabolize quercetin, forming mammalian metabolites. The results were different from those presented by other microorganisms previously utilized, attrackting attention because of the great diversity of reactions. Methylated, sulphated, monoglucuronidated, and glucuronidated conjugated metabolites were simultaneously detected.Biotransformações microbianas constituem uma alternativa importante como modelo para o estudo do metabolismo de medicamentos em mamíferos e são empregadas em processos sintéticos industriais com propósitos farmacêuticos. Diversos microrganismos com potencial para biotransformação têm sido encontrados através de screening intensivo e aplicados comercialmente. Dez cepas de fungos filamentosos do gênero Beauveria, isolados na região central do Brasil, e a cepa Beauveria bassiana ATCC 7159 foram avaliadas quanto à capacidade de biotransformação da quercetina. As reações de biotransformações foram realizadas por um período de 24 a 96 horas, e monitoradas através de espectrometria de massas do meio reacional. Todas as cepas foram capazes de metabolizar a quercetina, formando metabólitos encontrados nos mamíferos. Os resultados foram diferentes dos resultados apresentados por outros microrganismos utilizados anteriormente e
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Petroleum hydrocarbon assessment in the sediments of the northeastern Havana littoral, Cuba
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Companioni Dams, Eloy Yordad; Nunez Clemente, Ana Catalina; Cora Medina, Miriam Odette [Laboratorio de Quimica Ambiental, Centro de Investigaciones del Petroleo, Habana (Cuba)]. E-mail: elocompa@yahoo.com; Gonzalez Brovo, Luis [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear, Habana, (Cuba); Marbot Ramada, Rolando [Laboratorio de Quimica Analitica, Centro de Investigaciones del Petroleo, Habana (Cuba); Montes de Oca Porto, Rodny [Laboratorio Antidoping, Habana (Cuba); Rosabal Rodriguez, Maikel [Centro de Ingenieria y Manejo Ambiental de Bahias y Costas, Habana (Cuba); Diaz Diaz, Miguel angel [Laboratorio de Quimica Ambiental, Centro de Investigaciones del Petroleo, Habana (Cuba)
2009-02-15
As a part of a geochemical study, aliphatic and aromatic hydrocarbons were determined in surficial sediments, from a Cuban coastal zone located in the Northeastern Havana Littoral. Sediment samples were collected at 15 sites in this area, and then extracted and analyzed by gas chromatography with flame ionization and mass spectrometry detectors. Total concentration of both, aliphatic (AH) and aromatic (ArH) hydrocarbons, varied from 2.4 {+-} 0.2 to 105.1 {+-} 5.9 {mu}g/g (dry weight) and from 1.1 {+-} 0.2 to 38.4 {+-} 7.6 {mu}g/g (dry weight), respectively. The chromatography profile of AH was dominated by an unresolved complex mixture (UCM), and the presence of isoprenoid hydrocarbons, steranes and hopanes, indicated petroleum - related hydrocarbon inputs. The predominant concentration of phytoplanktonic molecular markers (pristane and nC17) in collected sediments, revealed the marine productivity in this sites. The anthropogenic contribution detected showed the impact of the petroleum exploration along this coastal area. [Spanish] Como parte de un estudio geoquimico se determinaron hidrocarburos alifaticos y aromaticos en sedimentos superficiales, de una zona costera situada en el Litoral Nordeste de La Habana. Las muestras de sedimento se colectaron en 15 estaciones de muestreo en esta area, y posteriormente se extrajeron y analizaron mediante cromatografia gaseosa con detectores de ionizacion a la llama y espectrometria de masas. Las concentraciones totales de hidrocarburos alifaticos (HA) e hidrocarburos aromaticos (HAr) variaron desde 2.4 {+-} 0.2 a 105.1 {+-} 5.9 {mu}g/g (peso eco) y desde 1.1 {+-} 0.2 a 38.4 {+-} 7.6 {mu}g/g (peso eco), respectivamente. El perfil cromatografico de los hidrocarburos alifaticos estuvo dominado por una mezcla compleja no resuelta (MCNR), y la presencia de hidrocarburos isoprenoides, esteranos y hopanos, indico el aporte de hidrocarburos derivados del petroleo. La concentracion predominante de marcadores moleculares
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Davidson, A. S.; Elliott, F.; Powell, R.; Swinburn, K. A. [United Kingdom Atomic Energy Authority, Windscale and Calder Works, Cumberland (United Kingdom)
1966-02-15
). La precision requerida del metodo de analisis quimico depende del numero de determinaciones que se efectuen en cada periodo contable. Asi, para un metodo minucioso pero impreciso es necesario proceder a un gran numero de analisis. Puede resultar mas economico efectuar menos determinaciones con un metodo mas preciso. En la memoria se exponen detalladamente los metodos para la determinacion del plutonio: a) radioquimicos, b) colorimetricos, con toronol, c) separacion del plutonio, formacion del complejo con exceso de EDTA y retrovaloracion del reactivo, d) volumetria, e) dilucion isotopica seguida de espectrometria de masas, y f) espectrometria diferencial. Tambien se resenan los metodos de determinacion del uranio: a) gravimetria en forma de U{sub 3}O{sub 8}, b) extraccion con eter seguida de gravimetria o calorimetria, c) volumetria, d) dilucion isotopica seguida de espectrometria de masas y e) determinacion del enriquecimiento por espectrometria de masas o por espectrografia del desplazamiento de las lineas de un espectro de emision. En todos los procedimientos contables se emplean patrones para controlar los analisis y descubrir las inexactidudes que deben corregirse. En la memoria se dan precisiones sobre todos los metodos y se indica cuales de ellos se emplean en la nueva planta de separacion. (author) [Russian] Vse cifry dlja podscheta kolichestva special'nyh materialov vkljuchajut odin ili bolee iz treh osnovnyh parametrov, a imenno: izmerenija na ustanovke, vzjatie obrazcov i vzjatie analizov. Chto kasaetsja izmerenij, provodimyh na ustanovke, to luchshe vsego ispol'zovat' vzveshivanie tam, gde jeto vozmozhno, naprimer, kolichestvo plutonija pri zagruzke v novuju ustanovku razdelenija izotopov opredeljaetsja na osnove vesa zagruzhennyh uranovyh sterzhnej. Podrobno obsuzhdajutsja metody izmerenija velichin, naprimer a) pnevmaticheskogo merkatora i b) indikatornogo metoda s ispol'zovaniem radioaktivnogo cezija. Privodjatsja proverennye vykladki kazhdogo metoda
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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...
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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)
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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
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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)
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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).
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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)
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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.
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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...
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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)
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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)
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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)
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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.
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Energy Technology Data Exchange (ETDEWEB)
Sanchez, Ligbel; Morales, Jose; Velasquez, Harvi; Portillo, Dennis; Cano, Yulixis; Montilla, Brinolfo; Iriarte, Nelkis, Mesa, Johan [Universidad del Zulia, Maracaibo (Venezuela)]. E-mail: ligbels@hotmail.com
2009-08-15
de emision naturales y antropicas, se incorporan en las gotas de lluvia a traves de varios procesos fisicoquimicos durante los eventos de precipitacion. El conocimiento de la composicion quimica de las precipitaciones es critico para el entendimiento de la contaminacion regional y local y sus efectos sobre los ecosistemas. Entre las sustancias acidas o potencialmente acidas envueltas en la formacion de la lluvia acida, se puede senalar los compuestos de azufre, nitrogeno y cloro. Un factor importante en las caracteristicas acido-base de la lluvia es la emision de materiales alcalinos como carbonato de calcio, magnesio y amoniaco, que se encuentran generalmente como un vapor capaz de neutralizar los acidos sulfurico y nitrico. Los datos de la quimica de las lluvias, en este trabajo, provienen de varios sitios de la ciudad de Maracaibo, las muestras de agua de lluvia fueron recolectadas en tres periodos repartidos entre los anos 1989 y 2001, con equipos de muestreo manuales y automaticos. Para los diferentes analisis realizados se utilizaron un espectrometro de absorcion atomica modalidad llama, Perkin-Elmer 3110 y un cromatografo ionico con detector de conductividad, marca Dionex 2000i/SP. El pH-PPV en la lluvia de Maracaibo es 4.8, indicativo de una atmosfera ligeramente acida e influenciada por: SO{sub 4}{sup -2}, Cl{sup -} y NO{sub 3}{sup -} en 86 %. La especie neutralizante mas importante es el NH{sub 3}, aunque las concentraciones de Ca{sup +2} y Mg{sup +2} son aportes adicionales al proceso de neutralizacion atmosferica. El mayor flujo de depositacion humeda fue exhibido por: NH{sub 4}{sup +}, SO{sub 4}{sup -2}, Cl{sup -} y NO{sub 3}{sup -} con 67.5 %. Estadisticamente, se evidencio una alta correlacion entre SO4{sup *}, Cl{sup *} y NO{sub 3}{sup -} con el ion H{sup +} (p<0.05), ratificando su influencia en la acidez de las lluvias de Maracaibo. Se concluye que solo una pequena fraccion de los iones potencialmente acidos contribuyen a la acidez libre de las
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Energy Technology Data Exchange (ETDEWEB)
Elliot, M. N.; Grover, J. R.; Hardwick, W. H. [Atomic Energy Research Establishment, Harwell (United Kingdom)
1963-02-15
comme milieu de stockage, en les comparant aux verres au borosilicate. (author) [Spanish] El principal factor que es preciso tener en cuenta al proceder a la eleccion de un vidrio adecuado para almacenar por largos periodos desechos de productos de fision es el metodo de almacenamiento que se va a aplicar; el segundo factor es el grado de seguridad que ofrece la elaboracion del vidrio en un establecimiento de alta actividad. A su vez, los factores que interesan para el almacenamiento son la resistencia a la lixiviacion, la estabilidad termica y a las radiaciones y la proporcion de desechos que se pueden incorporar a la masa vitrea, mientras que las propiedados fisicas y quimicas de los aditivos vitrificantes, asi como el punto de fusion y la viscosidad del vidrio mismo, son factores que intervienen mas bien en el proceso de elaboracion. Los autores examinan la importancia relativa de todos estos factores. Exponen luego los resultados del estudio experimental de los vidrios al borosilicato que se han elegido para, los ensayos en instalacion piloto, incluso el efecto de dosis de radiacion hasta 10{sup 12} rad sobre sus propiedades fisicas y quimicas. Tambien examinaron vidrios de otras composiciones y compararon su posible utilidad, como medio de almacenamiento, con la de los vidrios al borosilicato. (author) [Russian] Steklo dlja dlitel'nogo hranenija othoDov, soderzhashhih produkty delenija, dolzhno vybirat'sja, vo-pervyh s uchetom predpolagaemogo metoda hranenija i , vo-vtoryh, s uchetom vozmozhnosti ego poluchenija na vysokoradioaktivnyh ustanovkah. Vazhnymi faktorami s tochki zrenija hranenija javljajutsja: stojkost' protiv vyshhelachivanjja, teplostojkost' i radiacionnaja stojkost', a takzhe predel'naja dolja vvodimyh othodov; chto zhe kasaetsja fizicheskogo haraktera i himicheskih svojstv jelementov, dobavljaemyh dlja stekloobrajeovanija, a takzhe tochki plavlenija i vjazkosti stekla, to jeti faktory kasajutsja processa izgotovlenija. Obsuzhdaetsja otnositel
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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
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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.
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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.
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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)
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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.
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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.
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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, ...
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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)
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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%.
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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.
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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)
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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)
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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)
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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)
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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.
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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)
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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)
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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.
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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)
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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)
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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)
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Energy Technology Data Exchange (ETDEWEB)
Munoz Ledo, Ramon; Ley Koo, Marcos [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Varela Ham, Ruben [Universidad Autonoma Metropolitana, Mexico, D. F. (Mexico)
1993-12-31
A problem is set up of a reacting flow which occurs in a gas exhausting duct, which is boiled down to a problem of initial conditions (temperature, pressure and concentration of species) freeing the selection of reaction mechanisms. Through some pre-established algorithms calculation routines can be programmed in specific problems of chemistry kinetics. With the calculation routines set forth in base of the selected mechanism, the temperature, pressure, etc., conditions, a general program is obtained containing the differential equations for the mechanisms, and with its solution, with a certain degree of uncertainty, the gases at a duct outlet can be predicted. The exhaust gases will carry unburned particles and products that can be polluting or not. If we vary the working conditions, we can find the optimum values to work with equipment that produces exhaust gases, anticipating with it the more efficient utilization of the equipment and the energy with the least possible pollution. [Espanol] Se plantea un problema de un flujo reactivo que se lleva a cabo en un ducto de salida de gases de escape, para lo cual se reduce a un problema de condiciones iniciales (temperatura, presion y concentracion de especies), y dejando en libertad la seleccion de mecanismos de reaccion. Mediante algunos algoritmos preestablecidos se pueden programar las rutinas de calculo en problemas especificos de cinetica quimica. Con las rutinas de calculo planteadas en base al mecanismo seleccionado, las condiciones de temperatura, presion, etc. se obtiene un programa general que contiene las ecuaciones diferenciales para el mecanismo y con su solucion se puede predecir con cierto grado de incertidumbre los gases a la salida de un ducto, los gases de salida llevaran particulas inquemadas y productos que pueden ser contaminantes o no, si hacemos variacion en las condiciones de trabajo podemos encontrar los valores optimos para trabajar con equipos que producen gases de escape, previendo con ello
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Microbiological corrosion in low carbon steels; Corrosion microbiologica en aceros de bajo carbono
Energy Technology Data Exchange (ETDEWEB)
Medina-Custodio, O; Ortiz-Prado, A; Jacobo-Armendariz, V. H; Schouwenaars-Franssens, R [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: medina_1979@yahoo.com; armandoo@servidor.unam.mx; vjacobo@dgapa.unam.mx; raf_schouweenaars@yahoo.com
2009-01-15
The Microbiologically Induced Corrosion affects several industries, such as oil industry where it is estimated that 20% to 30% pipes failures are related with microorganism. The chemical reactions generate ions transfer, this validate the use of electrochemical technique for its analysis. Coupons submerged in a nutritional medium with presence and absence of three different microorganisms during two periods, 48 hours and 28 days were studied. Polarization resistance (Rp) and Electrochemical Impedance Spectroscopy (EIS) techniques were applied to determine the corrosively of the systems. The results show a greater corrosive effect of abiotic systems, this indicates a microorganisms protection effect to the metal, opposite to the first hypothesis. This result was ratified observing surface coupons by using Scanning Electron Microscopy (SEM) technique. A possible mechanism based on Evans - Tafel graph is proposed to explain inhibitor microorganism effect. [Spanish] La corrosion microbiologica es un tipo comun de deterioro que afecta diversas industrias, una de ellas es la petrolera en la que se estiman que el 20% o 30% de fallas en las tuberias de trasporte de hidrocarburos es favorecida por microorganismos. Las reacciones quimicas que sustentan estos, generan transferencia de iones, lo que justifica el empleo de tecnicas electroquimicas para su analisis. En este trabajo, se estudiaron probetas de acero de bajo carbono SAE 1018, sumergidas en un medio nutritivo rico en cloruros en presencia y ausencia de tres diferentes cargas microbianas, en tiempos de exposicion de 48 horas y 28 dias. Se realizaron ensayos de resistencia a la polarizacion (Rp) y espectroscopia de impedancia electroquimica (EIS) para determinar el efecto corrosivo de los diferentes sistemas. Los resultados muestran que el medio abiotico causa el mayor efecto corrosivo, lo que indica un efecto protector de los microorganismos al metal contradiciendo la hipotesis inicialmente propuesta. La observacion
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Energy Technology Data Exchange (ETDEWEB)
Gonalez Partida, Eduardo [Universidad Nacional Autonoma de Mexico (Mexico); Tello Hinojosa, Enrique [Comision Federal de Electricidad (Mexico); Pal Verma, Mahendra [Instituto de Investigaciones Electricas (Mexico)
2001-03-01
The Las Tres Virgenes geothermal field is a liquid dominated system. The separated produced by the wells are sodium-chloride type, which is a characteristic of totally equilibrated geothermal brine. The temperature of water-rock interaction in the reservoir is 280 Celsius degrees. the chemical composition of gases corresponds to the one expected in a geothermal environment. The CO{sub 2} is the predominating gas and it is superior in 90% in weight to the total of existing gases. The gas contents is less than 1% in weight, in the case of the wells LV-1 and LV-3. It is also possible to conclude that the gases are in equilibrium with the liquid phase at a temperature of 280 Celsius degrees. With respect to water quality, it is saline, from high to very high and the contents of exchangeable sodium is also very high, resulting in waters not fit for agricultural usage. [Spanish] El yacimiento geotermico de Las Tres Virgenes, en Baja California Sur, Mexico, es un sistema de liquido dominante, en donde el agua separada producida por los pozos presenta un caracter clorurado-sodico caracteristico de una salmuera de origen geotermico totalmente equilibrada. El sistema agua-roca se encuentra en equilibrio a una temperatura de 280 grados centigrados , dicha temperatura son congruentes con las estimadas para las fases gaseosas y liquidas. La composicion quimica de los gases corresponde a la esperada en un ambiente geotermico. El CO{sub 2} es el predominante y es superior a 90% en peso del total de los gases presentes. El contenido de gas es menor de 1% en peso en el caso de los pozos LV-1 y LV-3. Tambien se puede concluir que los gases estan en equilibrio en las fases liquidas a una temperatura de 280 grados centigrados. Con respecto a la calidad del agua, presenta una salinidad de alta a muy alta y el contenido de sodio intercambiable tambien es muy alto, por lo que dichas aguas no son muy aptas para el cultivo.
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Energy Technology Data Exchange (ETDEWEB)
Bravo Alvarez, H; Soto Ayala, R; Sosa Echeverria, R; Sanchez Alvarez, P [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)
2003-10-15
Actually, acid rain is considered as a potential problem that affects materials and ecosystems. The effect on monuments, made mainly from limestone, has been studied for long time. In this work, a sample of limestone from Tulum, Qintana Roo, was studied. The following parameters were measured: density, porosity and percentage of water adsorption. Also, the sample was irrigated with acid rain prepared in the laboratory (pH = 4.6), based in the chemical composition of 56 rain samples from Puerto Morelos, Quintana Roo, in 1994 and 1995. The results obtained show that acid rain is neutralized by calcium carbonate from the limestone. The high calcium concentrations in the effluent, show that limestone is dissolved by acid rain. Superficial recession was 4.4 {mu}m/year under experimental conditions used. [Spanish] Actualmente la lluvia acida se ha convertido en un problema potencial que afecta en mayor o menor grado a materiales y a los ecosistemas. El efecto que causa la lluvia acida en monumentos construidos fundamentalmente de roca caliza, ha sido objeto de muchas investigaciones realizadas, prioritariamente, por paises que poseen estructuras, cuyo material de construccion es caliza. En este trabajo de investigacion se estudio una muestra de roca caliza proveniente de los monumentos mayas de Tulum, Quintana Roo. Se determinaron los parametros de densidad, porosidad y porcentaje de adsorcion de agua. Asimismo, se efectuo la irrigacion de la muestra con lluvia acida (pH aprox.4.6), preparada en el laboratorio con base en la composicion quimica que se determino en 56 muestras de agua de lluvia provenientes de Puerto Morelos, punto cercano a los monumentos de Tulum, Quintana Roo, durante los anos 1994 y 1995. Los resultados permiten concluir que la lluvia acida sufre un proceso de naturalizacion con el carbonato de calcio de la roca caliza. Las altas concentraciones de calcio en el efluente, mostraron que la roca caliza sufrio una disolucion con la lluvia acida. La
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Energy Technology Data Exchange (ETDEWEB)
Bravo Alvarez, H.; Soto Ayala, R.; Sosa Echeverria, R.; Sanchez Alvarez, P. [Facultad de Ingenieria, UNAM, Mexico, D.F. (Mexico)
2003-12-01
Actually, acid rain is considered as a potential problem that affects materials and ecosystems. The effect on monuments, made mainly from limestone, has been studied for long time. In this work, a sample of limestone from Tulum, Quintana Roo, was studied. The following parameters were measured: density, porosity and percentage of water adsorption. Also, the sample was irrigated with acid rain prepared in the laboratory (pH 4.6), based in the chemical composition of 56 rain samples from Puerto Morelos, Quintana Roo, in 1994 and 1995. The results obtained show that acid rain is neutralized by calcium carbonate from the limestone. The high calcium concentrations in the effluent show that limestone is dissolved by acid rain. Superficial recession was 4.4 {mu}m/year under experimental conditions used. [Spanish] Actualmente la lluvia acida se ha convertido en un problema potencial que afecta en mayor o menor grado a materiales y a los ecosistemas. El efecto que causa la lluvia acida en monumentos construidos fundamentalmente de roca caliza, ha sido objeto de muchas investigaciones realizadas, prioritariamente, por paises que poseen estructuras, cuyo material de construccion es caliza. En este trabajo de investigacion se estudio una muestra de roca caliza proveniente de los monumentos mayas de Tulum, Quintana Roo. Se determinaron los parametros de densidad, porosidad y porcentaje de adsorcion de agua. Asimismo, se efectuo la irrigacion de la muestra con lluvia acida (pH aprox. 4.6), preparada en el laboratorio con base en la composicion quimica que se determino en 56 muestras de agua de lluvia provenientes de Puerto Morelos, punto cercano a los monumentos de Tulum, Quintana Roo, durante los anos 1994 y 1995. Los resultados permiten concluir que la lluvia acida sufre un proceso de neutralizacion con el carbonato de calcio de la roca caliza. Las altas concentraciones de calcio en el efluente, mostraron que la roca caliza sufrio una disolucion con la lluvia acida. La
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Simulation of the phenomenon of single-phase and two-phase natural circulation
International Nuclear Information System (INIS)
Castrillo, Lazara Silveira
1998-02-01
Natural convection phenomenon is often used to remove the residual heat from the surfaces of bodies where the heat is generated e.g. during accidents or transients of nuclear power plants. Experimental study of natural circulation can be done in small scale experimental circuits and the results can be extrapolated for larger operational facilities. The numerical analysis of transients can be carried out by using large computational codes that simulate the thermohydraulic behavior in such facilities. The computational code RELAP5/MOD2, (Reactor Excursion and Leak Analysis Program) was developed by U.S. Nuclear Regulatory Commissions's. Division of Reactor Safety Research with the objective of analysis of transients and postulated accidents in the light water reactor (LWR) systems, including small and large ruptures with loss of coolant accidents (LOCA's). The results obtained by the simulation of single-phase and two-phase natural circulation, using the RELAP5/MOD2, are presented in this work. The study was carried out using the experimental circuit built at the 'Departamento de Engenharia Quimica da Escola Politecnica da Universidade de Sao Paulo'. In the circuit, two experiments were carried out with different conditions of power and mass flow, obtaining a single-phase regime with a level of power of 4706 W and flow of 5.10 -5 m 3 /s (3 l/min) and a two-phase regime with a level of power of 6536 W and secondary flow 2,33.10 -5 m 3 /s (1,4 l/min). The study allowed tio evaluate the capacity of the code for representing such phenomena as well as comparing the transients obtained theoretically with the experimental results. The comparative analysis shows that the code represents fairly well the single-phase transient, but the results for two-phase transients, starting from the nodalization and calibration used for the case single-phase transient, did not reproduce faithfully some experimental results. (author)
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Energy Technology Data Exchange (ETDEWEB)
Castrillo, Lazara Silveira
1998-02-01
Natural convection phenomenon is often used to remove the residual heat from the surfaces of bodies where the heat is generated e.g. during accidents or transients of nuclear power plants. Experimental study of natural circulation can be done in small scale experimental circuits and the results can be extrapolated for larger operational facilities. The numerical analysis of transients can be carried out by using large computational codes that simulate the thermohydraulic behavior in such facilities. The computational code RELAP5/MOD2, (Reactor Excursion and Leak Analysis Program) was developed by U.S. Nuclear Regulatory Commissions's. Division of Reactor Safety Research with the objective of analysis of transients and postulated accidents in the light water reactor (LWR) systems, including small and large ruptures with loss of coolant accidents (LOCA's). The results obtained by the simulation of single-phase and two-phase natural circulation, using the RELAP5/MOD2, are presented in this work. The study was carried out using the experimental circuit built at the 'Departamento de Engenharia Quimica da Escola Politecnica da Universidade de Sao Paulo'. In the circuit, two experiments were carried out with different conditions of power and mass flow, obtaining a single-phase regime with a level of power of 4706 W and flow of 5.10{sup -5} m{sup 3}/s (3 l/min) and a two-phase regime with a level of power of 6536 W and secondary flow 2,33.10{sup -5} m{sup 3}/s (1,4 l/min). The study allowed tio evaluate the capacity of the code for representing such phenomena as well as comparing the transients obtained theoretically with the experimental results. The comparative analysis shows that the code represents fairly well the single-phase transient, but the results for two-phase transients, starting from the nodalization and calibration used for the case single-phase transient, did not reproduce faithfully some experimental results. (author)
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Energy Technology Data Exchange (ETDEWEB)
Flores Hernandez, J. Roberto [Instituto de Investigaciones Electricas Cuernavaca, Morelos (Mexico)] e-mail: jrflores@iie.org.mx; Reyes, Brenda [UNAM. Facultad de Quimica, Mexico D.F. (Mexico); Barbosa P., Romeli [Centro de Investigacion en Energia, UNAM, Temixco, Morelos (Mexico); Cano Castillo, Ulises; Albarran, Lorena [Instituto de Investigaciones Electricas Cuernavaca, Morelos (Mexico)
2009-09-15
Membrane electrode assemblies (MEA) are the most important part of PEM fuel cells since their interface results in the electrochemical reactions that make the generation of electricity possible. The MEA is composed of a proton exchange membrane, both sides of which are impregnated with a catalyst layer, normally of carbon-supported platinum. Depending on the technique used for its fabrication (atomization, serigraphy, brush methods, chemical reduction, etc.), the properties of the MEA can be different in terms of porosity, distribution of the catalyst, thickness and structure of the catalyst layer, and the quality of the union between the catalyst layer and the membrane, etc. Currently, the porosity of the electrodes is generated by isopropanol evaporation (solvent used in the dye) during the fabrication process conducted in the Instituto de Investigaciones Electricas (IIE). This document presents the results obtained from adding a porous agent to the catalytic dye base composition used in the fabrication of MEA at the IIE. [Spanish] Los Ensambles Membrana-Electrodo (MEA's) son la parte mas importante en las celdas de combustibles tipo PEM, ya que en su interfaz se llevan a cabo las reacciones electroquimicas que hacen posible la generacion de electricidad. El MEA esta compuesto de una membrana de intercambio protonico a la cual se le impregna en ambos lados una capa catalitica normalmente de platino soportado en carbon. Dependiendo de la tecnica empleada en su fabricacion (atomizado, serigrafia, brocha, reduccion quimica, etc.), las propiedades del MEA pueden ser diferentes en cuanto a porosidad, distribucion del catalizador, grosor y estructura de la capa catalitica, asi como la calidad de la union entre la capa catalizadora y la membrana, etc. Actualmente, la porosidad de los electrodos es generada por la evaporacion del isopropanol (solvente utilizado en la tinta) durante el proceso de fabricacion que se realiza en el Instituto de Investigaciones
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Energy Technology Data Exchange (ETDEWEB)
Altamirano-Bedolla, J. A.; Manzanares-Papayanopoulos, E.; Herrera-Velarde, J. R. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: emp@iie.org.mx
2010-11-15
The usage of hydrocarbons, such as natural gas, oil products and coal, will be the main source of energy to the mankind for next generations. Therefore, the actual research and technological developments point out to employ with high efficiency those fuels. The main interests are to release most of the energy as possible and to guide the combustion reactions. It is well known that during the combustion process of coal, the chemical energy is converted to thermal energy, which it allows the steam production, and therefore to produce energy through an electric generator. The main interest of the work presented here is to study the behavior of the coal combustion processes in function of the approximate analysis and some associate indices of that analysis, to point out the optimization of the coal usage as main fuel in electrical power generation plants. [Spanish] El uso de hidrocarburos como son el gas natural, los derivados del petroleo y el carbon mineral, continuara siendo en las proximas decadas la principal fuente de energia de la humanidad. Por consiguiente, la investigacion cientifica y los desarrollos tecnologicos actualmente se enfocan en emplear de manera mas eficiente dichos combustibles, satisfaciendo entre otros factores, dos intereses principales: liberar la mayor cantidad de energia, reduciendo al minimo el material combustible no quemado, y direccionar las reacciones del proceso de combustion para minimizar la cantidad de productos no deseados resultantes de la reaccion. A traves de los procesos quimicos de combustion del carbon, se transforma la energia quimica a energia termica, lo que permite la produccion de vapor para a su vez impulsar una turbina la cual esta acoplada a un generador electrico. El objetivo del presente trabajo es el estudio del comportamiento de los procesos quimicos que se llevan a cabo durante las reacciones de combus-tion del carbon en funcion del analisis aproximado y de los indices asociados resultantes de dicho analisis; lo
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Energy Technology Data Exchange (ETDEWEB)
Munoz Ledo, Ramon; Ley Koo, Marcos [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Varela Ham, Ruben [Universidad Autonoma Metropolitana, Mexico, D. F. (Mexico)
1992-12-31
A problem is set up of a reacting flow which occurs in a gas exhausting duct, which is boiled down to a problem of initial conditions (temperature, pressure and concentration of species) freeing the selection of reaction mechanisms. Through some pre-established algorithms calculation routines can be programmed in specific problems of chemistry kinetics. With the calculation routines set forth in base of the selected mechanism, the temperature, pressure, etc., conditions, a general program is obtained containing the differential equations for the mechanisms, and with its solution, with a certain degree of uncertainty, the gases at a duct outlet can be predicted. The exhaust gases will carry unburned particles and products that can be polluting or not. If we vary the working conditions, we can find the optimum values to work with equipment that produces exhaust gases, anticipating with it the more efficient utilization of the equipment and the energy with the least possible pollution. [Espanol] Se plantea un problema de un flujo reactivo que se lleva a cabo en un ducto de salida de gases de escape, para lo cual se reduce a un problema de condiciones iniciales (temperatura, presion y concentracion de especies), y dejando en libertad la seleccion de mecanismos de reaccion. Mediante algunos algoritmos preestablecidos se pueden programar las rutinas de calculo en problemas especificos de cinetica quimica. Con las rutinas de calculo planteadas en base al mecanismo seleccionado, las condiciones de temperatura, presion, etc. se obtiene un programa general que contiene las ecuaciones diferenciales para el mecanismo y con su solucion se puede predecir con cierto grado de incertidumbre los gases a la salida de un ducto, los gases de salida llevaran particulas inquemadas y productos que pueden ser contaminantes o no, si hacemos variacion en las condiciones de trabajo podemos encontrar los valores optimos para trabajar con equipos que producen gases de escape, previendo con ello
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GIS based Hydrogeological Vulnerability Mapping of Groundwater Resources in Jerash Area-Jordan
Energy Technology Data Exchange (ETDEWEB)
Hammouri, N [Department of Earth and Environmental Sciences, Faculty of Natural Resources and Environment, Hashemite University, Zarqa (Jordan); El-Naqa, A [Department of Water Management and Environment, Faculty of Natural Resources and Environment, Hashemite University, Zarqa (Jordan)
2008-04-15
This paper presents groundwater vulnerability mapping for Jerash area, north Jordan generated using EPIK and DRASTIC models. These models have been implemented using GIS to delineate groundwater protection zones and to suggest a protection plan to improve groundwater quality of the major springs and wells. Most of the groundwater resources in the study area are polluted and bacteria and nitrate levels are high. Different sources of groundwater pollution have been identified. Domestic wastewater is considered as a major source of pollution. Urban runoff, fertilizers from agricultural return flows and solid waste disposal appear to be secondary sources. The most relevant vulnerability class of EPIK map is very high which accounts for about 41 % of the total area. While in the DRASTIC vulnerability map, areas with high vulnerability were only about 23 % of the total area. There is a good correlation between vulnerability maps obtained from both models with microbiological and chemical pollution evidences. There is also a good agreement between the areas classified as highly vulnerable and those that have high levels of pollution. [Spanish] El estudio de vulnerabilidad de aguas subterraneas en la region de Yerash, Jordania fue obtenido mediante las metodologias de EPIK y DRASTIC. Se uso GIS para mapear las zonas protegidas y para sugerir un plan de proteccion para mejorar la calidad del agua subterranea en los principales manantiales y pozos. Los niveles de contaminacion bacteriana y de nitratos son elevados. El efluente domestico es la fuente mas importante de contaminacion; vienen en segundo lugar la precipitacion en zonas urbanas, los fertilizantes agricolas y los desechos solidos. En el mapa de EPIK, la vulnerabilidad extrema abarca hasta 41% del area total; en cambio, en el mapa de DRASTIC las areas de alta vulnerabilidad ocupan solo un 23% del area. La correlacion de los datos de contaminacion microbiana y quimica con ambos mapas der vulnerabilidad es buena
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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.
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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...
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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)
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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)
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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)
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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.
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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.
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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)
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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...
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Analysis of electrocautery generated smoke by chromatographic-mass spectrometry.
Kalil, Jefferson; Pessine, Francisco B T; Fidelis, Carlos H V; Menezes, Fabio H; Palma, Paulo Cesar Rodrigues
2016-01-01
to analyze the chemical components of the smoke from electrocautery from coagulating muscle and liver tissues of pigs. we collected smoke produced by electrocautery applied to porcine tissue in previously evacuated bottles, with qualitative and quantitative analysis of the compounds present through the hyphenated technique gas chromatography / mass spectrometry. there was a majority of decanal aldehyde in the fumes from the subcutaneous, muscle and liver tissues. Fumes of subcutaneous and muscular tissues also showed the presence of hexanal and phenol. In the fumes of subcutaneous and liver tissues we also found toluene and limonene and, finally, nonanal smoke was present in the muscle and liver tissues. there is increasing evidence showing that smoke from electrocautery used in subcutaneous, muscle and liver tissue is harmful to human health. Thus, there is need to reduce exposure to it or wear masks with filters capable of retaining these particles. analisar quimicamente os componentes da fumaça do eletrocautério, provenientes da coagulação de tecidos, muscular e hepático de suino. coleta de fumaça produzida por eletrocauterização de tecido porcino em frascos previamente evacuados com análise qualitativa e quantitativa dos compostos presentes, através de técnica hifenada, cromatografia a gás/espectrometria de massas. houve presença majoritária do aldeído decanal nas fumaças provenientes dos tecidos subcutâneo, muscular e hepático. Fumaças dos tecidos subcutâneo e muscular mostraram também a presença de hexanal e fenol. Nas fumaças dos tecidos subcutâneo e hepático foram encontrados ainda tolueno e limoneno e, por fim, nonanal estava presente nas fumaças dos tecidos muscular e hepático. há número crescente de evidências mostrando que fumaça proveniente de eletrocauterização de tecidos subcutâneo, muscular e hepático é nociva à saúde de seres humanos. Portanto, há necessidade de reduzir a exposição a ela ou usar máscara com
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Directory of Open Access Journals (Sweden)
Nerendra Narain
2004-06-01
Full Text Available Entre as inúmeras frutas tropicais e subtropicais produzidas no Brasil, duas que se destacam do ponto de vista do aroma da polpa são maracujá amarelo (Passiflora edulis forma Flavicarpa e cajá (Spondias mombin L.. Os voláteis da polpa destas frutas foram capturados pela técnica de headspace dinâmico e analisados no sistema de cromatografia gasosa de alta resolução e espectrometria de massa. Foram identificados 48 e 33 compostos voláteis na polpa de maracujá e cajá, respectivamente. Os compostos voláteis predominantes na polpa de maracujá pertenceram às classes de ésteres (59,24%, aldeídos (15,27%, cetonas (11,70% e álcoois (6,56%, enquanto na polpa de cajá as principais classes de compostos foram de ésteres (48,76%, álcoois (21,69%, aldeídos (11,61% e cetonas (4,19%. Outros compostos aromáticos característicos foram para maracujá: beta-ionona e linalol e para cajá: gama-octalactona e ácidos butírico e hexanóico.Among the numerous tropical and sub-tropical fruits produced in Brazil, two that attain relatively greater importance from the point of view of aroma of their pulp are yellow passion fruit (Passiflora edulis forma Flavicarpa and yellow mombin (Spondias mombin L.. The volatile components in the pulp of these fruits were captured by dynamic headspace technique and were analyzed in a system of high-resolution gas chromatography and mass spectrometry. Forty-eight and thirty-one volatile compounds were identified in passion fruit and yellow mombin fruit pulp, respectively. The predominant volatile compounds in passion fruit pulp belonged to the classes of esters (59.24%, aldehydes (15.27%, ketones (11.70% and alcohols (6.56% while in the yellow mombin pulp, the principal classes of compounds were esters (48.76%, alcohols (21.69%. aldehydes (11.61% and ketones (4.19%. The other characteristic aroma compounds for passion fruit were beta-ionone and linalool and for yellow mombin were gamma-octalactone, butanoic and
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Directory of Open Access Journals (Sweden)
Rodrigo L. Fabri
2012-12-01
Full Text Available The bioactivity guided fractionation of the dichloromethane extract of Mitracarpus frigidus afforded the pyranonaphthoquinone psychorubrin. This compound, hitherto unknown in the genus Mitracarpus, had its biological activity evaluated against one panel of bacteria and two fungi, three tumor cell lines (HL60, Jurkat and MCF-7 and four Leishmania species. Its identity was confirmed unambiguously by ¹H, 13C, ¹H-COSY, IR and UV-Vis spectroscopy and mass spectrometry. Psychorubrin displayed a very promising antitumor with IC50 of 4.5, 5.6 and 1.1 µM for HL60, Jurkat and MCF-7 cell lines, respectively. Antimicrobial activity, mainly against Cryptococcus neoformans (MIC of 87.3 µM was observed. A pronounced antileishmanial potential was also verified with IC50 varying from 1.7 to 2.7 µM for the Leishmania species tested. This is the first report of the presence of pyranonapthoquinones in the Mitracarpus genus, which may serve as a chemotaxonomical marker.O fracionamento biomonitorado do extrato diclorometânico de Mitracarpus frigidus forneceu a piranonaftoquinona psicorubrina. Essa substância, até então desconhecida no gênero Mitracarpus, teve sua atividade biológica avaliada contra várias bactérias e dois fungos, três linhagens de células tumorais (HL60, Jurkat e MCF-7 e quatro espécies de Leishmania. Sua estrutura foi confirmada por meio de ¹H, 13C, ¹H-COSY, IR e UV-Vis e espectrometria de massas. Psicorubrina exibiu uma atividade antitumoral promissora com CI50 de 4,5, 5,6 e 1,1 µM para HL60, Jurkat e MCF-7, respectivamente. Atividade antimicrobiana, principalmente contra Cryptococcus neoformans (CIM de 87,3 µM, foi observada. Um pronunciado potencial leishmanicida também foi verificado com CI50 variando de 1,7 - 2,7 µM para as diferentes espécies de Leishmania testadas. Este é o primeiro relato da presença de piranonaftoquinonas no gênero Mitracarpus, que poderão ser úteis como marcadores quimiotaxonômicos.
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Directory of Open Access Journals (Sweden)
Aline Correa Mazzoni
2012-09-01
Full Text Available Caxias do Sul hosts the second largest metal-mechanic pole in Brazil, which increases the risk of atmospheric contamination. With the aim of identifying species that might be useful as indicators of atmospheric deposition of metals, 15 species of mosses from an urban and a rural setting were analyzed and compared with specimens deposited at the Herbarium of the Universidade de Caxias do Sul. Metal concentrations (Zn, Ni, Cd, Cr, Cu and Pb were determined using Atomic Absorption Spectrometry (AAS. The Mann-Whitney test indicated concentrations of Zn, Cu, Pb and Cr that were significantly different between the urban and rural areas. Additionally, Concentrations of Zn, Cd, Cu and Pb were significantly higher in recently collected samples. The species Thuidium tomentosum Besch., Sematophyllum subpinnatum (Brid. E. Britton, Helicodontium capillare (Hedw. A. Jaeger, Schlotheimia jamesonii (W.-Arnott Brid. and Meteorium deppei (Hornsch. ex Müll. Hal. Mitt. are potential biomonitors of atmospheric metal deposition.Caxias do Sul sedia o segundo maior pólo metal mecânico do Brasil, apresentando elevado risco de contaminação atmosférica. Com o objetivo de identificar espécies úteis como indicadoras da deposição atmosférica de metais, foram analisadas 15 espécies de musgos procedentes da zona urbana e da área rural e espécimens depositados no Herbário da Universidade de Caxias do Sul. Os metais (Zn, Ni, Cd, Cr, Cu e Pb foram determinados por meio de Espectrometria de Absorção Atômica (AAS. O Teste de Mann-Whitney indicou diferenças significativas nas concentrações de Zn, Cu, Pb e Cr entre as áreas urbana e rural. Um aumento significativo na presença de Zn, Cd, Cu e Pb foi evidenciado nas amostras recentes. As espécies Thuidium tomentosum Besch., Sematophyllum subpinnatum (Brid. E. Britton, Helicodontium capillare (Hedw. A. Jaeger, Schlotheimia jamesonii (W.-Arnott Brid. e Meteorium deppei (Hornsch. ex Müll. Hal. Mitt. são indicadas
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Directory of Open Access Journals (Sweden)
C.F. Aquino
2014-01-01
Full Text Available Objetivou-se avaliar a ação de diferentes concentrações de óleos essenciais de três plantas medicinais sobre o crescimento micelial, a produção e a germinação de conídios de Colletotrichum gloeosporioides (Penz.. Utilizou-se os óleos essenciais de Lippia sidoides Cham., Cymbopogon citratus (DC Stapf. e Ocimum gratissimum L. em cinco concentrações (0 µL mL-1, 1 µL mL-1, 3 µL mL-1, 5 µL mL-1 e 7 µL mL-1 com 4 repetições no delineamento inteiramente casualizado, em esquema fatorial 5x3. Os óleos foram analisados por cromatografia gasosa acoplada com espectrometria de massas. Para todas as características verificou-se efeito significativo da interação "Óleo" versus "Concentração". O óleo essencial de C. citratus proporcionou a maior inibição do crescimento micelial em todas as concentrações testadas. Os outros óleos não se diferenciaram, exceto a partir da concentração de 5 µL mL-1, onde o óleo de L. sidoides foi superior ao óleo de O. gratissimum. Na produção e germinação de conídios, o óleo de C. citratus, foi superior aos óleos de L. sidoides e de O. gratissimum nas concentrações de 1 µL mL-1 e 3 µL mL-1, inibindo completamente a produção e germinação a partir da concentração de 3 µL mL-1. As concentrações influenciam em todas as variáveis, ajustando-se à equação do modelo linear. Observa-se o decréscimo nessas, à medida em que se aumentam as concentrações dos óleos testados. Os óleos essenciais testados possuem efeito fungitóxico e fungistático.
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Directory of Open Access Journals (Sweden)
Paulo Eduardo Pardo
2004-10-01
Full Text Available Com o objetivo de estudar as concentrações de zinco da sola do casco de bovinos com e sem lesões podais, suplementados ou não com levedura seca, foram selecionadas e examinadas 60 vacas, escolhidas aleatoriamente, de um rebanho de 150 animais. Formaram-se quatro grupos de 15 animais, sendo o primeiro com animais com lesões podais e suplementados com levedura, o segundo com animais com lesões podais e sem suplementação de levedura, o terceiro com animais sem lesões podais e suplementados com levedura e o quarto com animais sem lesões podais e sem a suplementação de levedura. As concentrações de zinco da sola do casco foram determinadas por espectrometria de absorção atômica com chama (AAS. A comparação estatística das concentrações de zinco nas amostras foram submetidos à análise de variância, seguida pelo teste de Tukey, para comparação de médias. As médias das concentrações de zinco da sola do casco dos animais dos quatro grupos, quando comparadas estatisticamente, apresentaram diferença estatística significativa, somente nos animais com lesões podais e suplementados com levedura.With the goal of studying the hoof sole zinc concentrations of cow with and without foot lesions, suplemented or not with dried yeast from sugarcane; 60 cows were chosen from milking of 150 animals. Four groups of 15 animals were formed being the first one of animals with foot lesions and with supplemental yeast, the second one of animals with lesions and without supplemental yeast, the third group of animals without foot lesions and with supplemental yeast and the fourth one of animals without foot lesions and without supplemental yeast. Hoof sole zinc was determined by the Atomic Absortion Spectrophotometry (AAS. The results were statistically evaluated by analysis of variable, followed by Tukey’s test to compare mean levels. The mean concentration of zinc in the hoof sole of the groups statistically, significant showed differences
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Directory of Open Access Journals (Sweden)
Saulo Rios Mariz
2003-03-01
Full Text Available O uso indevido de anfetaminas tem preocupado as autoridades sanitárias em todo o mundo. No Brasil, destacam-se os anorexígenos anfetamínicos como o femproporex, que, no organismo, se biotransforma em anfetamina. Apesar de ser controlado por legislação específica, este fármaco tem sido amplamente utilizado em nosso país. Nas análises toxicológicas para verificação do uso de fármacos e drogas de abuso, têm-se empregado diferentes amostras biológicas. Mais recentemente a utilização do cabelo tem sido preconizada principalmente por informar sobre um uso a longo prazo da substância. A técnica para identificação de anfetaminas em cabelo é a cromatografia em fase gasosa acoplada à espectrometria de massas (CG-EM. A partir de um método descrito na literatura foram desenvolvidos estudos para avaliação da imunofluorescência polarizada como técnica de triagem na identificaçao de anfetamina em cabelo de usuários de anfetamínicos. Os resultados obtidos indicam que o método otimizado pode ser utilizado como triagem na identificação de anfetamina em cabelo.The amphetamine abuse is a preoccupation of public health authorities all over the world. In Brazil, anoretic drugs like fenproporex have been much used. Fenproporex is metabolically dealkylated to amphetamine in the human body. In spite of its legal control, it has been abused in the country. Different samples have been used to identify the drug in toxicological analyses. Hair samples have been proposed recently to identify and study the long-term use of the drug. CG-MG is the technique used to identify amphetamines in hair samples. Following a method proposed in specific literature, some studies have been developed to evaluate the application of the fluorescence polarization imunoassay (FPIA to identify amphetamine in hair samples of fenproporex users. The results show that the standard method may be used as screening in the identification of amphetamine by FPIA in hair
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Directory of Open Access Journals (Sweden)
Roberto Santos Barbiéri
2006-06-01
Full Text Available 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, [(C6H52SnMand 2] {Mand = C6H5CH(OHCOO], 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 ação biocida sobre o fungo Fusarium oxysporum f. sp. cubense, sendo mais efetivo que o ácido (±-mandélico livre. No entanto, a atividade biocida do composto foi menos intensa que a observada para cloreto de estanho hidratado, acetato de trifenilestanho e hidreto de trifenilestanho, empregados para fins de comparação. Nos testes de germinação de conídios e microconídios do mesmo fungo, na presença de [(C6H52SnMand 2], os índices de germinação ficaram abaixo de 11%.The present paper refers to the synthesis and characterization of a new organotin compound that was obtained by reaction of (±-mandelic acid with triphenyltin hydride in acetonitrile medium under reflux. According to hydrogen and carbon elemental analysis, infrared spectroscopy and high resolution mass spectrometry the formula of such compounds is (C6H52SnMand 2 {Mand = C6H5CH(OHCOO}. An octahedral complex, with the phenyl groups in trans position was proposed for its structure. It was observed that this compound was active against the fungus Fusarium oxysporum f. sp. cubense. The biocide effect was more intense than the one observed for(±-mandelic acid. However, it was less efficient than tin chloride hydrate, triphenyltin acetate and triphenyltin hydride. In germination assays with conides and microconides of the same fungus in the presence of [(C6H52SnMand 2], the germination rates were below 11%.
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Energy Technology Data Exchange (ETDEWEB)
Padmasree, K. P.; Diaz-Guillen, M. R.; Diaz-Guillen, J. A.; Mendoza, E. M.; Fuentes, A. F. [Cinvestav, unidad Saltillo, Ramos Arizpe, Coahuila (Mexico)]. E-mail: padma512@yahoo.com
2009-09-15
Lithium ion conducting glasses have been extensively investigated due to their potential application as solid state amorphous electrolytes in lithium rechargeable batteries. The use of glassy electrolytes in all solid state devices may provide numerous advantages like increased safety, facility of fabrication and miniaturization and having a higher conductivity than those of the crystalline counterparts. In this work, we prepared and studied the Lithium ion conducting glassy solid electrolytes of the composition {sub x}Li{sub 2}O-(1-x)[0.5B{sub 2}O{sub 3} -0.5P{sub 2}O{sub 5}] where 20
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Juliana Possavatz
2014-01-01
Full Text Available O rio Cuiabá é um importante tributário do rio Paraguai, cuja bacia é de grande importância por agasalhar o Pantanal, a maior área úmida do planeta. A base econômica da bacia hidrográfica do rio Cuiabá é a produção agrícola e pecuária que, para manter elevada produtividade, requer grandes quantidades de insumos agrícolas como os pesticidas que, podem atingir diversos ambientes devido aos processos de dispersão que ocorrem após sua introdução no ambiente. Os sedimentos desempenham importante papel para a caracterização da poluição de rios devido a seu potencial de acumulação de poluentes. Este estudo objetivou avaliar a contaminação por pesticidas usados nas lavouras plantadas na bacia do rio Cuiabá, MT. Para tanto, amostras de sedimento de fundo foram coletadas mensalmente de agosto de 2011 a julho de 2012. Para a determinação dos pesticidas atrazina, cipermetrina, clorpirifós, endossulfam (α, β e seu metabólito endossulfam sulfato, lambda-cialotrina, malationa, metolacloro, metribuzim, parationa metílica, permetrina e trifuralina no sedimento utilizou-se método multirresíduo que consiste na extração sólido-líquido por agitação mecânica seguida de purificação por extração líquido-líquido e identificação e quantificação por cromatografia a gás acoplada a espectrometria de massas. Resíduos de pesticidas foram identificados em amostras coletadas em agosto e setembro de 2011 e janeiro, fevereiro, abril e julho de 2012, em concentrações variando de 5,7 a 79,3 µg kg-1 . Embora a frequência de detecção tenha sido baixa, esses resultados indicam que há potencial de transporte de pesticidas usados na bacia do rio Cuiabá e seus tributários atingindo o Pantanal.
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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)
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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)
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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)
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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)
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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.
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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)
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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)
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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)
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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.
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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)
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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)
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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)
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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)
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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)
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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)
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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)
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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)
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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...
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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.
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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.
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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.
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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
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Alternate fuels; Combustibles alternos
Energy Technology Data Exchange (ETDEWEB)
Romero Paredes R, Hernando; Ambriz G, Juan Jose [Universidad Autonoma Metropolitana. Iztapalapa (Mexico)
2003-07-01
encuentran en la naturaleza, se cultivan o son desperdicios de origen organico. Asi se abordara de manera sucesiva las conversiones fisicas, quimicas y biologicas que pueden tener lugar en un proceso de produccion de un combustible alterno o mismo su uso directo como lo seria el quemar basura derivada de los bosques.
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Studies on magnetocaloric and magnetic coupling effects =
Amaral, Joao Cunha de Sequeira
O presente trabalho apresenta novas metodologias desenvolvidas para a analise das propriedades magneticas e magnetocaloricas de materiais, sustentadas em consideracoes teoricas a partir de modelos, nomeadamente a teoria de transicoes de fase de Landau, o modelo de campo medio molecular e a teoria de fenomeno critico. Sao propostos novos metodos de escala, permitindo a interpretacao de dados de magnetizacao de materiais numa perspectiva de campo medio molecular ou teoria de fenomeno critico. E apresentado um metodo de estimar a magnetizacao espontanea de um material ferromagnetico a partir de relacoes entropia/magnetizacao estabelecidas pelo modelo de campo medio molecular. A termodinamica das transicoes de fase magneticas de primeira ordem e estudada usando a teoria de Landau e de campo medio molecular (modelo de Bean-Rodbell), avaliando os efeitos de fenomenos fora de equilibrio e de condicoes de mistura de fase em estimativas do efeito magnetocalorico a partir de medidas magneticas. Efeitos de desordem, interpretados como uma distribuicao na interaccao magnetica entre ioes, estabelecem os efeitos de distribuicoes quimicas/estruturais nas propriedades magneticas e magnetocaloricas de materiais com transicoes de fase de segunda e de primeira ordem. O uso das metodologias apresentadas na interpretacao das propriedades magneticas de variados materiais ferromagneticos permitiu obter: 1) uma analise quantitativa da variacao de spin por iao Gadolinio devido a transicao estrutural do composto Gd5Si2Ge2, 2) a descricao da configuracao de cluster magnetico de ioes Mn na fase ferromagnetica em manganites da familia La-Sr e La-Ca, 3) a determinacao dos expoentes criticos β e δ do Niquel por metodos de escala, 4) a descricao do efeito da pressao nas propriedades magneticas e magnetocaloricas do composto LaFe11.5Si1.5 atraves do modelo de Bean-Rodbell, 5) uma estimativa da desordem em manganites ferromagneticas com transicoes de segunda e primeira ordem, 6) uma descricao de
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Directory of Open Access Journals (Sweden)
Rosa Márquez
2011-04-01
Full Text Available El propósito de este estudio fue aplicar la metodología de extracción con calor en condiciones de vacío a grasa cavitaria y exterior para la obtención de aceite de ñandú (Rhea americana con condiciones, una vez refinado, de humedad, acidez, índice de peróxidos, color y perfil de ácidos grasos compatibles con las exigencias del comercio internacional para los aceites de ratites.En cuanto al método de refinación seleccionado fue el método de refinación alcalina. Las condiciones elegidas para la neutralización fueron: NaOH 10% y 0.1% de exceso de la misma. Luego el aceite se lava hasta un contenido de jabones inferior a 50 ppm debido a que los mismos afectan el valor de acidez. De esta forma se lograron valores de acidez muy por debajo del límite requerido por la AEA (American Emu Association para el aceite de emú extra refinado. Se utilizó tierra de blanqueo Supreme 126 (marca Tonsil de Quimica Sumex S.A., en una concentración del 0.5 %.Se determinó que no existen diferencias sustanciales entre la grasa cavitaria y exterior y en el proceso de winterización se obtienen dos fracciones con perfil de ácidos grasos diferentes siendo la oleína más rica en ácidos grasos insaturados. El contenido de oleico prácticamente no varía entre las fracciones, mientras que el porcentaje de linoleíco (ácido graso esencial es superior para la oleína.En el presente trabajo se obtuvo un aceite cuyas características y parámetros de calidad son aceptables para los requerimientos internacionales que deben poseer los aceites para aplicación en cosmética, haciéndolo factible de comercializar. Por lo que los métodos de extracción y refinación adaptados para esta aplicación son adecuados y simples de aplicar.
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Energy Technology Data Exchange (ETDEWEB)
Leyva Noyola, Fatima; Solorza Feria, Omar [Centro de Investigacion y Estudios Superiores del IPN, Mexico, D.F. (Mexico)]. E-mail: fleyva@cinvestav.mx
2009-09-15
This work reports on the catalytic activity of RuPd, RuCo, PdCo and RuPdCo material for oxygen reduction reaction (ORR). These materials were synthesized using chemical reduction with NaBH{sub 4} as a reducing agent in THF, in ambient temperature and pressure conditions. The evaluation of the catalytic activity was done using cyclic voltamperometry (CV) and rotary disc electrode (RDE) in H{sub 2}SO{sub 4} 0.5 M. The kinetic results showed that the electrochemical reaction involves 4 electrons and the transfer of the first electron is the determinant stage. The values of {alpha}, i0 and the Tafel slope were very similar for the four materials studied, around 0.4, 5x10{sup -6} mA cm{sup -2} and 60 mV dec-1, respectively. Although these values are less than those reported for nanostructured platinum, they are better than those reported for other materials such as pure Pd, which enables them to be considered as cathode catalysts for a proton exchange membrane fuel cell. [Spanish] En este trabajo se reporta la actividad catalitica de los materiales RuPd, RuCo, PdCo y RuPdCo para la reaccion de reduccion de oxigeno (RRO). Estos materiales fueron sintetizados por el metodo de reduccion quimica, usando NaBH{sub 4} como agente reductor en THF, en condiciones de temperatura y presion ambiental. La evaluacion de la actividad catalitica fue realizada usando Voltamperometria Ciclica (VC) y Electrodo Disco Rotatorio (EDR) en H{sub 2}SO{sub 4} 0.5 M. Los resultados cineticos mostraron que la reaccion electroquimica procede por la via de 4 electrones y la etapa determinante es la transferencia del primer electron. Los valores de {alpha}, i0 y pendiente de Tafel fueron muy similares para los 4 materiales estudiados, siendo estos de alrededor de 0.4, 5x10{sup -6} mA cm{sup -2} y 60 mV dec{sup -1}, respectivamente. Sin embargo, aun cuando estos valores son menores que los reportados para platino nanoestructurado, son mejores que los reportados para otros materiales como el Pd puro
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International Nuclear Information System (INIS)
Rodenas, J.; Gallardo, S.; Ballester, S.; Hoyler, F.
2006-01-01
One of the features in the characterization of a drum containing radioactive wastes is to verify the activity of radionuclides contained in the drum. An H.P. Ge detector can be used for this measurement. However, it is necessary to perform an efficiency calibration for all geometries involved. In the framework of a joint project between the Departamento de Ingenieria Quimica y Nuclear (Universidad Politecnica de Valencia, Spain) and the Fachbereich Angewandte Naturwissenschaften und Technik (Fachhochschule Aachen, Abteilung Julich, Germany), different configurations for a drum containing radioactive sources have been implemented in the laboratory. A cylindrical drum of 850 mm height, a diameter equal to 560 mm and 3 mm of steel thickness has been used in the experimental measurements. The drum contains a clay ceramic matrix whose chemical composition is 55% SiO 2 , 40% of Al 2 O 3 and 5% of TiO 2 . Several vertical PVC tubes having a diameter of 30 mm are inserted in the drum at different distances from the central axis. In the experiment, a pack of point sources with 133 Ba, 60 Co and 137 Cs is introduced into each one of the tubes. A ring-shape distributed source is generated by rotating the drum around its axis during the measurement. The detector efficiency is determined experimentally for these configurations. On the other hand, a Monte Carlo model, using the M.C.N.P. code, has been developed to simulate the drum, the clay matrix and the PVC tubes. The effect of the drum spinning has been reproduced simulating a ring source with different diameters. The model also includes detailed detector geometry. Using this Monte Carlo model, the detector efficiency is calculated for each configuration implemented in the laboratory. Comparison of results from Monte Carlo simulation and experimental measurements should permit the validation of the M.C.N.P. model. Consequently it will be possible to obtain efficiency curves without experimental measurements. Therefore, these
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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)
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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)
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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)
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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.