WorldWideScience

Sample records for hidroxiapatita para aplicacao

  1. PROSPECÇÃO TECNOLÓGICA PARA BIOCOMPOSITO DE HIDROXIAPATITA COM POLIURETANOS E PROPRIEDADES OSTEOINDUTORAS

    Directory of Open Access Journals (Sweden)

    Francisco Xavier Nobre

    2016-03-01

    Full Text Available Os biopolimeros são macromoléculas que basicamente não agridem o meio ambiente no processo de degradação, e que apresentam características que os tornam viáveis no processo de reconstituição de tecido, liberação de fármacos, produção de embalagens para alimentos dentre outras. Os poliuretanos (PU são polímeros que dentre outros mecanimos de obtenção, podem ser sintetizados utilizando óleos vegetais e gorduras animais como materiais de partida, e que ao longo dos anos têm sido descritos como promissor na produção de próteses para diversas finalidades. Ao combinar polímeros com bioceramicas, biovidros ou similares as características combinam-se a fim de obter biomateriais que apresentem capacidade de ser atribuídos a sistemas biológicos, de tal forma que aumente a velocidade de reconstituição e sustentação principalmente do tecido ósseo. Com isso, o objetivo deste trabalho foi avaliar por meio de competências tecnológicas e artigos relacionados a materiais constituidos basicamente de hidroxiapatita com poliuretano e caracteristicas osteoindutoras no intervalo de anos entre 2000 à 2014. Os resultados descrevem que, o país que mais se destaca em quantidade de patentes depositadas relacionando todas as palavras chave é a China, seguida pela República da Coréia, e que a classificação internacional que mais teve frequência nas competências foi a que relaciona necessidades humanas (A. Palavras Chave: Hidroxiapatita; Poliuretano; Osteoindutor. 

  2. FABRICACIÓN Y CARACTERIZACIÓN DE UNA MATRIZ TRIDIMENSIONAL DE HIDROXIAPATITA MACROPOROSA PARA APLICACIÓN EN INGENIERÍA DE TEJIDOS ÓSEOS

    Directory of Open Access Journals (Sweden)

    Marcela Rincón

    2007-06-01

    Full Text Available La ingeniería de tejido óseo surge como una nueva opción para el tratamiento de muchos tipos de afecciones, entre ellas las enfermedades óseas, permitiendo resolver múltiples problemas en el área médica. El desarrollo de una matriz de hidroxiapatita para cultivo de células óseas permitirá contar con otra alternativa para enfrentar las enfermedades causadas en el hueso y articulaciones que frecuentemente llevan a la discapacidad en las personas. En este trabajo se obtuvo hidroxiapatita sintética por la ruta de precipitación a partir de fosfato de amonio NH4H2PO4 y nitrato de calcio Ca(NO32.4H2O. Se formaron matrices en las cuales se indujo macroporosidad con el agente natural Zea mays, con partículas entre 350 µm y 600 µm, y microporosidad con celulosa en proporciones peso/peso de 4% y 8%. Las muestras fueron caracterizadas con pruebas de compresión, microscopía electrónica de barrido (SEM, que incluyó espectroscopia por dispersión de energía de rayos X (EDS y difracción de rayos X (DRX. Se obtuvieron matrices macroporosas de hidroxiapatita cristalina con un diámetro de poro entre 300 µm y 500 µm en promedio, con porosidades entre 35,85% y 45,61%, densidades en el rango de 1,48-1,77 g/cm³ y relación Ca/P de 1,7. Para los bloques con 4% de agente microporoso la resistencia a la compresión fue de 1,06 MPa y el módulo de elasticidad, de 67,15 MPa. Los bloques con 8% tuvieron una resistencia a la compresión de 1,08 MPa y un módulo de elasticidad de 54,65 MPa.Bone tissue engineering came up as a new option treatment for different kinds of illness, among them bone diseases. All this development has allowed solving multiple medical problems. The development of a hydroxyapatite scaffold for bone cells culture will be another alternative to attend several diseases that are caused on bones and that usually lead to disabilities in people. In this study synthetic hydroxyapatite was produced by a precipitation route with amonium

  3. Injerto de tejido conectivo subpediculado con utilización de hidroxiapatita para aumento de reborde alveolar: reporte de un caso

    Directory of Open Access Journals (Sweden)

    Antonio José Díaz Caballero

    2013-10-01

    Full Text Available ResumenLa reconstrucción quirúrgica de rebordes atrofiados mediante injertos de tejido conectivo y la hidroxiapatita es una opción que permite la fijación de los implantes de manera estética y funcional, ofrece un resultado previsible con bajas tasas de morbilidad y una ganancia notable de tejido óseo y tejidos blandos, gracias a su alta biocompatibilidad, alta capacidad de regeneración del tejido, una perfecta integración y elevados resultados, bajo riesgo de infección y ausencia de signos de rechazo. Presentamos el caso de una paciente con una pérdida ósea marcada en la zona anterior del maxilar, secundaria a procesos inflamatorios periodontales con la posterior pérdida de órganos dentarios prematuros, lo que conlleva a una perdida ósea. Se le realizó la cirugía tomando porciones de tejido conectivo donadas por el mismo paciente con la posterior utilización de hidroxiapatita porosa en la zona receptora para así lograr el aumento del reborde que se encontraba atrófico.Se constatan buenos resultados como respuesta biológica al material y al procedimiento, con una adecuada respuesta clínica y radiográfica, por lo que se recomienda el uso de este material en el tratamiento de defectos óseos bucofaciales por su biocompatibilidad, debido a su similitud con el hueso. Considerando así que se abren nuevos horizontes con la utilización de este material en este tipo de afección. (Duazary 2008; 1: 48 - 55AbstractSurgical reconstruction of atrophies residual ridges by use of connective tissue grafts plus hydroxyapatite is an option that allows the implant fixation in an esthetic and functional manner, offers a predictable outcome with low rates of morbidity and a remarkable gain of bone and soft tissue, Thanks to its high biocompatibility, high capacity for regeneration of tissue, a perfect integration and high performance, low risk of infection and the absence of signs of rejection. In this paper we present the case of a patient

  4. Compósito de colágeno com silicato e hidroxiapatita como material para endodontia: preparação e caracterização = Collagen composite with silicate and hydroxyapatite as endodontic material: preparation and characterization

    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"

  5. Síntesis y análisis de hidroxiapatita

    Directory of Open Access Journals (Sweden)

    Martha Dorelly Rodríguez B.

    1998-09-01

    Full Text Available Se realiza un estudio sobre hidroxiapatita ceramizada, sintetizada en Colombia, para valorar sus propiedades fisicoquímicas, comparándola con dos productos norteamericanos, según normas de la USP en relación con la proporción cuantitativa de Ca/P, estructura mediante espectroscopía infrarroja, textura mediante microscopía electrónica de barrido, estabilidad y determinación de impurezas, encontrándose que el producto en estudio posee propiedades equivalentes con los productos de control.

  6. Recubrimientos de hidroxiapatita preparados mediante un proceso sol-gel

    Directory of Open Access Journals (Sweden)

    Peón, E.

    2005-12-01

    Full Text Available Hydroxyapatite coatings (HAp have been obtained starting from precursors of sol-gel type. The coatings previously oxidized were deposited on metal surfaces of a based on iron alloy so-called MA956. The alloys were at high temperatures, in order to improve the adhesion with the hydroxyapatite coatings. The sol-gel coating was obtained applying an aqueous route, using triethyl phosphite and aqueous calcium nitrate, as precursors of phosphorous and calcium, respectively. Different sintering thermal treatments were applied on the resulting gels in order to obtain a homogeneous, adherent and crystalline hydroxyapatite coating. The characterization techniques used for this study were optical microscopy, SEM/EDX, XDR and FTIR. Moreover, the adhesion between the hydroxylapatite coating and the substrate was assessed according to the ASTM D 3359-02 standard test method. The results of this study showed that the best thermal treatment is obtained for a sintering temperature of 550 °C during a time of 72 h.

    Se han preparado nuevos recubrimientos de hidroxiapatita (HAp obtenidos a partir de precursores de tipo sol-gel, depositados sobre sustratos metálicos de una aleación de base hierro denominada MA956, previamente oxidados a elevadas temperaturas, para mejorar la adherencia con los recubrimientos de hidroxiapatita. El recubrimiento sol-gel se obtuvo aplicando una ruta acuosa, utilizando como precursores del fósforo y del calcio trietilfosfito y nitrato cálcico tetrahidratado, respectivamente. Sobre los geles resultantes se aplicaron distintos tratamientos térmicos de sinterización, hasta la obtención de recubrimientos de hidroxiapatita homogéneos, adherentes y cristalinos. Las técnicas de caracterización utilizadas para realizar este estudio han sido microscopía óptica, MBE/EDX, DRX y FTIR. Así mismo, se ha determinado la adherencia entre el substrato y el recubrimiento de hidroxiapatita según la norma ASTM D 3359-02. Los resultados

  7. Estudo comparativo entre silicona e silicona revestida com hidroxiapatita com fins de inclusão

    Directory of Open Access Journals (Sweden)

    SILVA Cynthia Maria Freire da

    1998-01-01

    Full Text Available O objetivo desta investigação foi estudar a biocompatibilidade de materiais aloplásticos, que pudessem ser usados como próteses internas. Comparamos em nosso estudo as reações histológicas de dois materiais: silicona e a hidroxiapatita. Usando ratas da cepa Wistar, preparamos corpos de prova de silicona e de silicona revestida com hidroxiapatita e fizemos inclusões subcutâneas no dorso das ratas. Os cortes histológicos foram analisados após um período de 7, 14, 21, 30, 60, 90 e 120 dias e demonstraram que as inclusões das siliconas revestidas com hidroxiapatita são mais biocompatíveis do que as de silicona pura, já que não formam cápsula fibrosa. Estes resultados mostram que podemos indicar peças de silicona revestidas com hidroxiapatita para prótese interna.

  8. Uso de novos materiais para o capeamento pulpar (hidroxiapatita - HAp e fosfato tricálcico - β-TCP The use of new materials for pulp capping (hydroxyapatite - HAp and tricalcium phosphate - β-TCP

    Directory of Open Access Journals (Sweden)

    C. S. Delfino

    2010-12-01

    Full Text Available O capeamento pulpar é uma medida importante e muito usada no cotidiano da prática odontológica e, quando realizado de forma consciente, baseado em um bom diagnóstico da condição pulpar no momento da exposição, pode prevenir o dente de sofrer uma intervenção endodôntica. Além do hidróxido de cálcio, outros materiais vêm sendo testados quanto a sua ação em promover o reparo pulpar pela formação de ponte de dentina, após capeamento pulpar direto. Uma das alternativas de materiais viáveis para o capeamento pulpar são as cerâmicas à base de fosfatos de cálcio, destacando-se a hidroxiapatita (HAp e o fosfato tricálcico (β-TCP. Estes materiais não promovem a formação de área necrótica, característica da utilização do hidróxido de cálcio, são biocompatíveis e favorecem o reparo do tecido pulpar. Para avaliar os efeitos desses materiais no capeamento pulpar foi realizada esta revisão de literatura, abordando desde a resposta do tecido pulpar, até o protocolo para o uso clínico.Pulp capping is an important measure and one with a high rate of use in daily dental practice, and when it is conscientiously performed, based on good diagnosis of the pulp condition at the time of its exposure, it may prevent the tooth from requiring endodontic intervention. In addition to calcium hydroxide, other materials have been tested with regard to their action in promoting pulp repair by the formation of a dentin bridge after direct pulp capping. Some of the feasible alternative materials for pulp capping are calcium phosphate-based ceramics, with hydroxyapatite (HAp and tricalcium phosphate (β-TCP being outstanding. These materials do not promote formation of a necrotic area, characteristic of the use of calcium hydroxide, are biocompatible and favor pulp tissue repair. To evaluate the effects of these materials on pulp capping, this literature review was conducted, the approach being wide ranging in scope, from pulp response

  9. Resposta tecidual ao compósito 50% hidroxiapatita: 50% poli-hidroxibutirato para substituição óssea em coelhos Tissue response to the composite 50% hydroxyapatite: 50% polyhydroxybutyrate for bone substitution in rabbits

    Directory of Open Access Journals (Sweden)

    E.C. Carlo

    2009-08-01

    Full Text Available Avaliaram-se a biocompatibilidade, a osseointegração, a osseocondução e a biodegradação de compósitos de 50% hidroxiapatita (HAP-91® e 50% poli-hidroxibutirato. O compósito foi implantado em defeitos ósseos em 12 coelhos (grupo experimental, sendo comparado a defeitos não preenchidos (grupo-controle, de igual número. Os parâmetros clínicos dor, claudicação, infecção, deiscência e edema foram avaliados nos primeiros oito dias após a cirurgia e aos 45 e 90 dias. Radiografias foram realizadas aos oito, 45 e 90 dias após a cirurgia em quatro animais por grupo que, em seguida, foram submetidos à eutanásia para coleta de amostras destinadas a análises histológica e histomorfométrica. Não ocorreram diferenças entre os grupos para todos os parâmetros clínicos. Radiografias demonstraram um compósito com radiopacidade semelhante à do osso vizinho e contato direto entre osso e compósito aos 45 e 90 dias. Diferença significativa foi observada entre a porcentagem dos tecidos ósseo e conjuntivo dentro do defeito nos dias oito, 45 e 90, assim como na interface aos 45 e 90 dias. Foram observadas projeções dos tecidos ósseo e conjuntivo no interior do compósito e sinais de biodegradação na ausência de infiltrado inflamatório. Pode-se concluir que o compósito é biocompatível, osseocondutor, biodegradável e se integra ao tecido ósseo.The biocompatibility, osseointegration, osseoconductivity, and biodegradation of a 50-50% hydroxyapatite (HAP-91®-polyhydroxybutyrate were evaluated. The composite was implanted in bone defects of 12 rabbits (experimental group, being compared to unfilled defects (control group, 12 animals. The clinical parameters of pain, lameness, infection, dehiscence, and edema were evaluated during the first eight days and on the 45th and 90th days after surgery. Radiographs were taken in four animals per group at 8, 45, and 90 days after surgery, when animals were euthanized to collect samples for

  10. Scaffold of chitosan-sodium alginate and hydroxyapatite with application potential for bone regeneration; Scaffold de quitosana-alginato de sodio e hidroxiapatita com potencial de aplicacao para regeneracao ossea

    Energy Technology Data Exchange (ETDEWEB)

    Rebelo, Marcia de A.; Alves, Thais F.R.; Lopes, Francielly C.C.N; Oliveira Junior, Jose Martins de; Pontes, Katiusca S.; Fogaca, Bruna A.C.; Chaud, Marco V., E-mail: marco.chaud@prof.uniso.br [Universidade de Sorocaba (LABNUS/UNISO), Sorocaba, SP (Brazil). Laboratorio de Biomateriais e Nanotecnologia

    2015-07-01

    Scaffold for organic tissue regeneration are architectural, three-dimensional, porous, biocompatible and biodegradable devices. The first challenges to be met in the development of these devices to mimic the biomechanical properties of the target tissue. The aim of this study was to develop and to characterize scaffolds composed of chitosan (Ch), sodium alginate (SA), hydroxyapatite (HA). The scaffolds were obtained by lyophilization. HA has been incorporated into the polymer dispersion in Ch-AS concentration of 20 and 60%. The mechanical properties of the scaffold were determined by tensile and compression tests. Swelling capacity was assessed in the presence of simulated saliva, purified water, HCl 0.01M, NaOH 0.01M. The calcium content was quantified using fluorescence X-rays. Analysis of the results indicates that the Qt-AS-HA-60% scaffold obtained by lyophilization meets promising properties for bone tissue regeneration. (author)

  11. Avaliação retrospectiva de artrodese cervical com enxerto autólogo versus hidroxiapatita Estudio retrospectivo de la artrodesis cervical con autoinjerto versus hidroxiapatita Retrospective study of cervical arthrodesis with autograft versus hydroxyapatite graft

    Directory of Open Access Journals (Sweden)

    Yoshinobu Nagasse

    2010-12-01

    Full Text Available OBJETIVO: os autores realizaram um estudo e compararam o resultado radiográfico no uso de hidroxiapatita e enxerto de crista ilíaca (autólogo no tratamento cirúrgico de hérnia discal cervical em um nível, sendo realizada artrodese cervical anterior com placa. MÉTODOS: foi realizado estudo retrospectivo com pacientes submetidos à artrodese cervical comparando-se dois grupos de dez pacientes: um em que foi utilizado enxerto de hidroxiapatita e outro em que foi utilizado enxerto de crista ilíaca (autólogo. Radiografias pós-operatórias foram mensuradas e comparadas, à busca de perdas de alinhamento angular. RESULTADOS: os dois tipos de enxerto demonstraram manter alinhamento em taxas similares, sendo observada consolidação óssea em todos os pacientes. O estudo não mostrou fragmentação do enxerto de hidroxiapatita ou soltura do material de síntese. CONCLUSÃO: nesta pequena série de casos não foi observada diferença significativa entre os resultados da artrodese cervical anterior com enxerto de hidroxiapatita em relação ao enxerto autólogo de ilíaco.OBJETIVOS: los autores realizaram un estudio y compararon el resultado radiográfico en el uso del hidroxiapatita y injerto de cresta ilíaca (autólogo, en el tratamiento quirúrgico de hernia discal cervical en un nivel, siendo realizada artrodesis cervical anterior con placa. MÉTODOS: fue realizado un estudio retrospectivo con pacientes, que habían sido sometidos a la artrodesis cervical con injerto de hidroxiapatita o injerto de cresta iliaca b.z autologa. Las radiografías postoperatorias habían sido mensuradas y comparadas, buscando para las pérdidas de alineación angular. RESULTADOS: los dos tipos de injerto habían demostrado manutención de alineación similares, donde la consolidación fue observada en todos los pacientes. El estudio no demostró la fragmentación del injerto de hidroxiapatita o de soltar el material de síntesis. CONCLUSIÓN: en esta peque

  12. Caracterização microestrutural de compósitos de hidroxiapatita-alumina confeccionados pelo método da esponja polimérica

    Directory of Open Access Journals (Sweden)

    M. S. Abreu

    Full Text Available Resumo O aumento do número de cirurgias de substituição e reparação óssea propiciou o estudo e a disseminação do uso de biomateriais, devido à sua biocompatibilidade e custo inferior ao de outros materiais utilizados como implantes. A hidroxiapatita é um biomaterial eficaz para utilização em engenharia tecidual, por ela fazer parte da matriz óssea. Porém, sua baixa resistência mecânica torna necessária a adição de outros materiais objetivando aumentar tal propriedade. A alumina é um material bioinerte que tem sido bastante utilizado como reforço mecânico para a hidroxiapatita. Este trabalho buscou desenvolver, pelo método da esponja polimérica, arcabouços cerâmicos de hidroxiapatita-alumina nas proporções em massa 50%-50%, 60%-40% e 70%-30. Os corpos de prova foram calcinados a 550 °C e sinterizados a 1250, 1300 e 1350 °C para avaliar características microestruturais. Os resultados obtidos estão de acordo com a literatura, o que justifica a realização de ensaios de caracterização físico-mecânica.

  13. La hidroxiapatita en defectos óseos periodontales

    Directory of Open Access Journals (Sweden)

    Omelio Fontaine Machado

    2015-06-01

    Full Text Available La periodontitis es una enfermedad destructiva de los tejidos periodontales profundos, caracterizada por pérdida ósea progresiva; constituye la segunda causa de pérdida dentaria. Una opción terapéutica son los injertos de hidroxiapatita (HA, de naturaleza altamente biocompatible y osteoconductora. Se presentan dos casos de pacientes remitidos desde la atención primaria de salud, con movilidad dentaria grados II y III, recesión periodontal y compromiso óseo importante, bolsas periodontales reales, con factores de riesgo directos como: placa dental bacteriana, retención de alimentos, sangramiento e inflamación gingival, halitosis, pérdida de la morfología. Previa indicación de terapia medicamentosa y estudio hematológico, se procedió a la realización de un colgajo periodontal y colocación del biomaterial granulado, hidroxiapatita, en los defectos óseos. Se logró reducción del grado de movilidad dentaria, mejoría en el nivel de retracción gingival, disminución en la profundidad de las bolsas, desaparición de síntomas. No se observó respuesta adversa al tratamiento. Al examen radiográfico periapical se detectó grado de neoformación ósea, fueron evolucionados en consulta por un periodo de tres meses.

  14. BIOCOMPATIBILIDADE EM FILMES DE HIDROXIAPATITA REFORÇADA COM NANOTUBOS DE CARBONO

    Directory of Open Access Journals (Sweden)

    Natália Marassi Martinelli

    2016-11-01

    Full Text Available As características químicas e estruturais individuais de nanotubos de carbono (NTC e hidroxiapatita (HAp, principal constituinte da fase inorgânica do osso, possibilitam seu uso na área médica como materiais biocompatíveis em implantes e próteses. O objetivo deste trabalho é estudar a biocompatibilidade do compósito HAp/NTC eletrodepositadas comitantemente em aço 316. Para a produção dos compósitos os NTC foram dispersos na solução eletrolítica em concentrações de 1% e 3%. Os resultados obtidos in vitro, utilizando o ensaio da Lactato Desidrogenase (LDH, demostraram que nenhuma amostra causou citotoxicidade nas células osteoblásticas. Neste estudo, também foram avaliados genes relacionados à osteogênese, tais como: fosfatase alcalina (ALP, osteopontina (OPN, osteocalcina (OC por RT-qPCR (Transcrição Reversa – Reação em Cadeia da Polimerase quantitativa, após 14 dias. Os osteoblastos em contato com a HAp/NTC apresentaram aumento da expressão de genes importantes no processo de mineralização e maturação óssea. Os resultados demonstraram um grande potencial de aplicação clínica deste compósito.

  15. LA HIDROXIAPATITA, SU IMPORTANCIA EN LOS TEJIDOS MINERALIZADOS Y SU APLICACIÓN BIOMÉDICA

    OpenAIRE

    Margarita Victoria García-Garduño; José Reyes-Gasga

    2006-01-01

    La hidroxiapatita en los tejidos mineralizados reviste una gran importancia ya que se ha demostrado que es un material biocompatible, con aplicación biomédica en Odontología, Ortopedia y Cirugía Máxilofacial. Es el cristal principal de huesos y dientes ya que les confiere su dureza característica y, acompañado por la colágena, los huesos presentan determinada elasticidad. En la naturaleza se le encuentra formando parte de rocas metamórficas. En los tejidos vivos, la hidroxiapatita y sus precu...

  16. Obtención de recubrimientos de hidroxiapatita sobre titanio mediante el método biomimético

    Directory of Open Access Journals (Sweden)

    Paz, A.

    2011-04-01

    Full Text Available In this work, a study about the deposition of hydroxyapatite on a titanium substrate employing the biomimetic method is presented. A solution with high content of calcium and phosphorus (SCS was used. In addition, activation of titanium with hydrogen peroxide and hydrochloric acid and a subsequent heat treatment was performed. The characterization of materials used and the coating obtained was carried out by Infrared Spectroscopy (FT-IR, X-ray Diffraction (XRD, Scanning Electron Microscopy (SEM and Energy Dispersive X-ray Spectroscopy (EDX. As a result of the activation processes a hydrated titanium oxide was formed. On the active surface, a coating of hydroxyapatite was obtained after a period of 24 h, which has a thickness of about 2-4 μm.

    En el presente trabajo se realizó un estudio de la deposición de hidroxiapatita sobre un sustrato de titanio mediante el método biomimético. Para ello se empleó una disolución con elevado contenido de calcio y fósforo (SCS. Además, se realizó la activación del titanio a partir de la aplicación de procesos de oxidación con peróxido de hidrógeno y ácido clorhídrico con un posterior tratamiento térmico. La caracterización de los materiales empleados, así como de los recubrimientos obtenidos, se realizó mediante Espectroscopia Infrarroja (FT-IR, Difracción de Rayos X (DRX, Microscopia Electrónica de Barrido (MEB y Espectroscopia de Energía Dispersiva de Rayos X (EDX. Como resultado del proceso de activación se formó un óxido de titanio hidratado. Sobre la superficie activada se logró obtener un recubrimiento de hidroxiapatita en un período de 24 h, caracterizado por su elevada densidad y cristalinidad y por presentar un espesor entre 2-4 μm.

  17. EVALUACIÓN HISTOLÓGICA DE BIOCOMPATIBILIDAD Y BIOCONDUCCIÓN DEL COMPUESTO HIDROXIAPATITA - LIGNINA IMPLANTADO EN TIBIA DE CONEJOS

    Directory of Open Access Journals (Sweden)

    Marlene Vargas V

    2009-04-01

    Full Text Available Objetivo. Evaluar histologicamente la biocompatibilidad y propiedad óseoconductora del compuesto de hidroxiapatita - lignina implantado en tibias de conejos. Material y métodos. Se utilizaron 20 conejos de raza nueva Zelanda, en cada uno, la tibia izquierda fue tratada con el compuesto y la tibia derecha no fue tratada y sirvió como control. Con la ayuda de taladro manual y una broca se realizó un defecto óseo de aproximadamente 4 mm de diámetro en la superficie lateral proximal tibial, hasta alcanzar el canal medular. Dos comprimidos del compuesto (400 mg, se utilizaron para rellenar el defecto. El mismo procedimiento quirúrgico se realizó en el grupo control, sin la utilización del compuesto. Las evaluaciones histológicas se realizaron a los 8, 30, 60, 90 y 120 días postcirugía, para lo que fue necesaria la eutanasia de 4 animales por fecha de evaluación. Resultados. En las evaluaciones de 30, 60, 90 y 120 días se observó una formación ósea más acelerada y extensa en el grupo tratado al compararse las lecturas histológicas con el grupo control. Conclusiones. El compuesto hidroxiapatita-lignina permitió el crecimiento de tejido óseo desde los bordes hasta el centro del defecto a un ritmo de crecimiento mayor, con formación de hueso mas organizado que en el grupo control. Además se observó su integración al tejido óseo; lo que sugiere su biocompatibilidad y propiedad óseoconductora, hecho que permite recomendarlo como substituto.

  18. Efeito da temperatura em processos de sinterização de pós de hidroxiapatita

    Directory of Open Access Journals (Sweden)

    A. G. de S. Azevedo

    2015-03-01

    Full Text Available Amostras de hidroxiapatita foram sintetizadas por meio da precipitação de soluções aquosas contendo os íons precursores. O precipitado obtido foi lavado, seco, desaglomerado e peneirado com o intuito de se obter amostras em forma de pó e com granulometria homogênea. O material foi sinterizado em diferentes temperaturas e posteriormente caracterizado por difração de raios X, espectroscopia no infravermelho, microscopia eletrônica de varredura, análise termogravimétrica e termodiferencial e a quantificação da área superficial específica e porosidade foi realizada por meio dos métodos Brunauer-Emmett-Teller e Barret-Joyner-Halenda, respectivamente. Os pós apresentaram modificações na cristalinidade, morfologia e nas propriedades texturais com o aumento da temperatura. Novas fases foram identificadas nos difratogramas de raios X devido à decomposição do material, corroborando com resultados reportados. Houve o crescimento dos cristais, aumento da cristalinidade e diminuição da área de superfície específica, comprovando que as modificações ocorreram devido aos processos de sinterização, uma vez que a força motriz para esse processo é a diminuição da área de superfície específica.

  19. Hydroxyapatite granules used in the obliteration of mastoid cavities in rats Utilização de hidroxiapatita de cálcio no preenchimento de defeitos ósseos criados em mastoides de ratos

    Directory of Open Access Journals (Sweden)

    Rogério Hamerschmidt

    2011-06-01

    Full Text Available Prospective Experimental study in which we created a bony defect in the mastoids of rats and filled it up with hydroxyapatite to evaluate bone regeneration, to solve the problems of open cavities after mastoidectomies that frequently present with otorrhea, infection, granulation tissue and hearing loss. OBJECTIVE: The aim was to evaluate bone regeneration in defects created in the mastoids of rats, using hydroxyapatite, to see how much of the cavity we could reduce. MATERIAL AND METHODS: Twelve rats Wistar-Furth were used. A 0.5 x 0.5 cm bone defect was created in both temporal bones of the rats, and filled with 15 micrograms of hydroxyapatite. The left side was used as control. The animals were slaughtered 40 days afterwards and histology analyses were carried out. RESULTS: In the hydroxyapatite group, the new bone growth involved an area of 68.53% of the total; and in the control group it was only of 15.97%. DISCUSSION AND CONCLUSIOn: It was observed a very good hydroxyapatite integration to the temporal bone in this experimental model. The microscopic results were superior with the use of hydroxyapatite when compared to the control group. It is a safe method and easy to apply to solve the problems of open cavities with chronic discharge and difficult to clean.Estudo experimental prospectivo utilizando ratos que foram submetidos à realização de defeito ósseo em mastoide para avaliar o grau de regeneração óssea após preenchimento com hidroxiapatita de cálcio sintética, para resolver o problema das cavidades abertas pós-mastoidectomia que frequentemente se apresentam com secreção, tecido de granulação, otorreia e perda de audição. OBJETIVO: Avaliar a regeneração óssea em defeitos criados em mastoides de ratos, utilizando hidroxiapatita cáustica, avaliando quanto a cavidade mastoidea criada pode ser diminuída, por meio de microscopia óptica. MATERIAL E MÉTODO: Foram utilizados 12 ratos Wistar. Foi criado um defeito

  20. Emprego experimental da placa de compósito poli-hidroxibutirado/hidroxiapatita na fixação femoral em gatos

    Directory of Open Access Journals (Sweden)

    E.G.L. Alves

    2010-10-01

    Full Text Available Avaliou-se o compósito de poli-hidroxibutirado (PHB 70% e hidroxiapatita (HA 30% na forma de placas para fixação óssea em gatos. Foram usadas placas do compósito com 60mm de comprimento por 10mm de largura e espessura variando de 3mm no centro a 5mm nas extremidades, com seis orifícios. A placa do compósito foi empregada na fixação de osteotomia de fêmur em quatro gatos, totalizando seis intervenções. Verificou-se a ruptura de cinco placas (83,3% até o quarto dia e de uma placa (16,7% aos 21 dias, quando se observou um calo ósseo exuberante. O resultado da implantação da placa no gato mostrou que o compósito não possui resistência suficiente para ser empregado como placas de fixação de fêmur em gatos.

  1. Influencia de la incorporación de un co-monómero alcalino e hidroxiapatita en las propiedades de cementos óseos acrílicos

    Directory of Open Access Journals (Sweden)

    Karen Lozano

    2013-01-01

    Full Text Available Se formularon cementos óseos acrílicos utilizando una relación sólido / líquido de 2. El componente líquido se basó en metacrilato de metilo (MMA, como monómero y dimetil-p-toluidina (2.5% como acelerador; a su vez, el componente sólido consistió en perlas de polimetacrilato de metilo (PMMA como carga, sulfato de bario como agente radiopaco y peróxido de benzoilo (2% como iniciador. Finalmente, una hidroxiapatita como carga bioactiva y un metacrilato de dimetil amino etilo (DMAEM como co-monómero alcalino, fueron incorporados en diferentes porcentajes (0-20% p/p, para el primero y 0-10% p/p, para el segundo. Como era de esperarse, las muestras elaboradas con las formulaciones de cementos óseos acrílicos sin modificar, presentaron calores de reacción elevados (>80ºC y una resistencia a la compresión (124.0 MPa por encima de lo especificado en la norma ISO 5833. Con la incorporación de la hidroxiapatita y el co-monómero alcalino, se presentaron bajas temperaturas de polimerización, bajos módulos y resistencias mecánicas, así como la fijación de una capa similar a la apatita biológica en la superficie del material después de su inmersión por 30 días en un fluido biológico simulado.

  2. Influência do tempo de indução nas propriedades de hidroxiapatita porosa obtida por gelcasting de espumas Influence of the induction time on the properties of porous hydroxyapatite obtained by gelcasting foams

    Directory of Open Access Journals (Sweden)

    T. M. Volkmer

    2007-12-01

    Full Text Available Hidroxiapatita é uma cerâmica bioativa que permite o crescimento de tecido ósseo e revascularização da área implantada pela formação de ligação com a fase mineral dos ossos. Este estudo teve como objetivo a obtenção de blocos porosos de hidroxiapatita através do método gelcasting de espuma, sem a utilização de atmosfera controlada para a realização das polimerizações. O processo gelcasting de espumas consiste na incorporação de uma fase gasosa dispersa dentro de uma suspensão cerâmica contendo o pó cerâmico, água, defloculantes, ligantes e agentes de gelificação. O sistema de gelificação consiste no monômero acrilamida e no co-monômero N,N’ metilenobisacrilamida difuncional (MBAM. Foi estudada a variação das quantidades de iniciador e de acelerador e verificou-se a variação do tempo de indução e seus reflexos nas propriedades da hidroxiapatita porosa. Avaliou-se a porosidade, a macroestrutura, a distribuição de tamanho de poros e a permeabilidade. Verificou-se que é possível controlar a porosidade variando-se o tempo de indução e a ausência de atmosfera controlada não impediu a obtenção das peças porosas.Hydroxyapatite (HA is a bioactive ceramic that allows bone growth and revascularization of the area of implantation trough the formation of chemical bonding with the mineral phase of the bones. The aim of this work was to obtain porous blocks of HA by the gelcasting foams method without atmosphere control. The gelcasting foams process consists in the incorporation of a dispersed gaseous phase, with the help of a surfactant, inside a ceramic suspension containing the ceramic powder, water and gelation agents. The gelation system is composed by one monomer, acrylamide, and one comonomer, methylenebisacrylamide (MBAM. The effect of the accelerator and initiator amounts on the induction time, porosity, pore size distribution and permeability was evaluated. It was possible to control the porosity

  3. Hidroxiapatita en defectos óseos craneales: Comunicación previa

    Directory of Open Access Journals (Sweden)

    Susana A Fernández Benítez

    1997-12-01

    Full Text Available Se exponen los resultados iniciales de un ensayo experimental y clínico, con gránulos de hidroxiapatita como implante en defectos óseos craneales aun radiológicos y microscópicos (BAAF el tiempo de los pasos de osificación craneal. Hubo crecimiento de fibroblasto en 7 días; en 2 meses y medio, crecimiento de osteoblastos y de hueso intramembranoso. En 3 meses la plastia presentaba consistencia ósea palpableThe initial results of an experimental and clinical assay using hydroxyapatite granules as implants in skull defects over 3 cm are exposed. An attempt is made to verify by clinical, radiological and microscopic examinations (BAAF the time of the cranial ossification steps. It was observed a growth of fibroblasts in 7 days, and of osteoblasts and intramembranous bone in 2 months and a half. 3 months later the plastic presented a palpable osteal consistency

  4. Estudio de la calidad de recubrimientos de hidroxiapatita sobre acero inoxidable implantable aplicados mediante proyección térmica con plasma

    OpenAIRE

    Bernal Gaona, Sandra Paola

    2013-01-01

    El objetivo de este trabajo de investigación se basó en el estudio de los parámetros del proceso de deposición de recubrimientos de hidroxiapatita sobre substratos de acero inoxidable implantable mediante el proceso de proyección térmica con plasma atmosférico, que pueden afectar de forma significativa la calidad de los recubrimientos, en cuanto a su cristalinidad y adherencia al substrato. Como parámetros a evaluar se tomaron el tamaño de grano de la hidroxiapatita, el espesor...

  5. Formación de hidroxiapatita, Ca5(PO43∙OH, en presencia de silicatos

    Directory of Open Access Journals (Sweden)

    Puertas, F.

    1994-12-01

    Full Text Available Hydroxyapatite Ca5(PO43OH (HAp is a crystalline phase which has several applications within the domain of special cements. This phase takes an important role in the cement reactions for the reconstruction of skeletal functions (medical domain. It is used also to improve properties of dental material. On the other hand, it is investigated to develop chemically bonded ceramics. In this paper we study the formation of HAp with β-C2S and C5PS, using some compositions in the rich lime portion of the system CaO-SiO2-P2O5-H2O (at atmospheric pressure and open system. These compositions lie in the range of: CaO: 67-71 %; SiO2: 3-18%; P2O5: 9-29% (Wt%. The preparations are made using solid state reactions, with thermal treatment at open system. The identification of phases was carried out using X-ray diffraction, Infra-Red absorption and Differential Thermal Analysis. We delimit a spectroscopy little domain lies in the range of CaO-69,5-70%; P2O5-16,2-19,5%; SiO2-11,1-13,6%. Within this domain, the crystalline phases solid state compatibility at temperature near 1000ºC are HAp, β-C2S, C5PS.La hidroxiapatita, Ca5(PO43OH (HAp, es una fase cristalina que tiene diversas aplicaciones en el ámbito de determinados cementos especiales. Esa fase juega un importante papel en las reacciones de cementos utilizados en medicina para la reconstrucción defunciones del esqueleto. Se utiliza también para mejorar propiedades de materiales de aplicación odontológica. Por otra parte, se está estudiando para desarrollar conglomerantes cerámicos. En el presente trabajo se estudia la compatibilidad en estado sólido de la HAp con β-C2S y C5PS utilizando, a presión atmosférica y recinto abierto, composiciones en la zona rica en cal del sistema CaO-SiO2-P2O5-H2O dentro de los límites siguientes. CaO: 67-71 %; SiO2: 3-18%; P2O5: 9-29% (en peso. El tratamiento térmico se realizó en estado sólido y en atmósfera abierta. La identificación de las fases se realizó a

  6. Electrical characteristics of the hydroxyapatite for biomedical applications; Caracteristicas electricas de la hidroxiapatita para aplicaciones biomedicas

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Buisan N, M.G.; Mendez G, M.M. [Laboratorio de Corrosion, ESFM-IPN, 07738 Mexico D.F. (Mexico)

    2006-07-01

    The electric characteristics of hydroxyapatite films were studied (HAP) deposited on metallic substrates oxidized naturally. The substrates was made of steel 316L and of titanium. These materials are used in reconstructive surgery for prosthesis and osseous implants. The studies were carried out with the techniques of potentiostatic polarization and faraday impedance. The potentiostatic polarization reveals that the very well-known piezoelectricity of the HAp subsists after the coating processes (it captures thermal and spray-pyrolysis). Its also revealed a semiconductor behavior of the HAp that until now had not been reported. This characteristic is important, by its relationship with the stability of the HAp coating in front of corrosion processes in the alive tissues. The results of the impedance tests were mathematically analyzed starting from the Nyquist diagrams, of Bode and of power. The physical interpretation is presented under the form of equivalent circuits (CE). In the case of the HAp on a steel 316L substrate, the CE is a Rancles-Voigt module that corresponds to the behavior of a dielectric with flights. In the case of the titanium substrate an element of constant phase appears to high frequencies (CPE), in series with the Rancles-Voigt module. The CPE reveals the presence of a rectifier of the metal/SC-n type that only it could be located in the interface among the titanium and its natural oxide (TiO{sub 2}). The absence of the CPE in the case of the steel 316L substrate indicates that the natural oxide (Cr{sub 2}O{sub 3}) it doesn't form with the steel a Schottky diode, possibly because the chromite is as a SC-n degenerate. On the interface Ti/TiO{sub 2} exists results qualitatively identical by other researchers that have worked with the same impedance technique, but applied by humid via (EIS). The CE that have proposed are based on the anodic processes of accretion/dissolution of the film at low pH. This proposal is questioned by our results, obtained under non electrochemical conditions. In accordance with our interpretation, the answer in frequencies of the system Ti/TiO{sub 2}/HAp can separate in two well differentiated ranges: that of low frequency, where operates the CE Rancles-Voigt that contains the information on the HAp; and that of high frequency, where operates the CPE that contain the information on the union Ti/TiO{sub 2}. This spectral resolution is, in principle, very convenient. However, when it is sought to characterize the HAp and the study should be carried out at low frequencies, the necessity to obtain an acceptable statistics implies a great lost of time. This unfavorable circumstance cannot be obviated by means of the Kramers-Kronig transformations, clearly inapplicable in these systems. (Author)

  7. Matriz para ingenieria de tejido oseo: modificacion superficial con zinc Estudio preliminar

    OpenAIRE

    Martinez, Cristian; Olmedo, Daniel; Ozols, Andres

    2013-01-01

    El objetivo del presente trabajo es desarrollar un metodo de sintesis de matrices para ingenieria de tejidos, capaces de acelerar los procesos reparativos y disminuir el riesgo de infeccion, destinadas a cirugias reconstructivas que involucren el tejido oseo. A este fin se emplea la fase mineral de hueso bovino, la hidroxiapatita, conservando su estructura tridimensional. Esta se obtiene a partir de un proceso de lavado quimico, seguido de un proceso termico que elimina todos los componentes ...

  8. CARACTERÍSTICAS CRISTALOQUÍMICAS DE LA HIDROXIAPATITA SINTÉTICA TRATADA A DIFERENTES TEMPERATURAS

    Directory of Open Access Journals (Sweden)

    Marta Elena Londoño

    Full Text Available La hidroxiapatita sintética (HA es un fosfato de calcio con una composición química muy similar a la del hueso humano, lo cual la hace biocompatible con los tejidos vivos. La biocompatibilidad posibilita su uso en variadas aplicaciones médicas. En esta investigación se realizó un seguimiento a las propiedades cristaloquímicas de muestras de HA sintética tratadas a diferentes temperaturas, las que se sometieron a solución fisiológica de Ringer durante periodos de 5 y de 30 días. La medición de la conductividad y el análisis de las muestras, por medio de espectrofotometría UV-VIS, análisis por ion selectivo, DRX, FTIR y SEM, permitieron mostrar la gran dependencia de la cristalinidad con el tratamiento térmico. La muestra más cristalina se obtuvo a una temperatura de 1050 °C. La mayor solubilidad se presentó en las muestras más cristalinas; además, se evidenció la presencia de dos mecanismos que compiten cuando las muestras se someten a solución Ringer: la disolución y la precipitación.

  9. Implantes de hidroxiapatita em falhas ósseas produzidas no fêmur de ratos submetidos ao tabagismo passivo Hydroxyapatite implants in bone defects produced in rat femurs submitted to passive tobacco exposure

    Directory of Open Access Journals (Sweden)

    Thiago Cerizza Pinheiro

    2008-10-01

    Full Text Available INTRODUÇÃO: Defeitos com perdas de massa óssea são freqüentemente tratados com enxertos ósseos autógenos. Implantes de biomateriais, como hidroxiapatita (HA, também têm sido utilizados com a mesma finalidade, substituindo os enxertos autógenos. Contudo, as condições de saúde do tecido ósseo são fundamentais para que haja a osteointegração do implante. Assim, o consumo excessivo de tabaco, de forma ativa ou passiva, pode prejudicar o processo de neoformação óssea frente ao implante de hidroxiapatita, devido a seus efeitos deletérios sobre o tecido ósseo. OBJETIVO: Avaliar as condições nutricionais dos animais e o processo de neoformação óssea quando grânulos de hidroxiapatita porosa são implantados em falhas ósseas no fêmur de ratos submetidos ao tabagismo passivo. MÉTODOS: Foram implantados grânulos de hidroxiapatita porosa em defeitos ósseos produzidos na epífise distal do fêmur esquerdo de ratos sujeitos ao tabagismo passivo prolongado. Os animais foram acompanhados ao longo do tratamento do tabagismo com duração de seis meses avaliando suas condições físicas. Após oito semanas do implante ósseo do biomaterial, os animais foram sacrificados e as amostras da área do implante submetidas aos métodos histológicos de rotina e mantidas em blocos de parafina para análise histológica, morfométrica, e radiológica. RESULTADOS: Identificou-se que a variação de massa do grupo experimental foi mais intensa quando comparada com a do grupo controle. Quanto aos achados radiológicos, observou-se aparente imagem mais radiolúcida e organizada no grupo controle. Na análise morfológica, houve melhor fechamento do defeito ósseo bem como a osteointegração da hidroxiapatita no grupo controle. Ao comparar o volume de osso formado na área receptora do fêmur, entre o grupo controle e experimental, notou-se que os valores encontrados para os animais submetidos ao tabagismo passivo foram significativamente

  10. Plasma rico em plaquetas combinado a hidroxiapatita na formação do calo ósseo em fraturas induzidas experimentalmente no rádio de cães Platelet-rich plasma combined with hydroxyapatite on bone callus formation in experimental radii fractures in dogs

    Directory of Open Access Journals (Sweden)

    Silmara Bonomi da Silva

    2007-08-01

    Full Text Available Avaliou-se, no presente estudo, os efeitos do plasma rico em plaquetas (PRP autógeno combinado a hidroxiapatita não-absorvível na formação do calo ósseo em fraturas diafisárias induzidas experimentalmente em rádio de cães e fixadas com placas e parafusos ósseos. Foram utilizados oito cães adultos sem raça definida, machos ou fêmeas, com pesos compreendidos entre 5 e 15kg. Induziu-se na diáfise de ambos os rádios defeito ósseo correspondente a 25% do diâmetro do mesmo. No rádio direito (grupo HA/PRP, implantou-se plasma rico em plaquetas combinado a hidroxiapatita. No rádio esquerdo (grupo HA, implantou-se somente a hidroxiapatita. Para a obtenção do PRP, empregou-se protocolo simplificado utilizando centrífuga laboratorial comum. Comparou-se entre os grupos a evolução clínica dos animais, o tempo de formação e a densidade do calo ósseo por exames radiográficos simples e pela técnica de densitometria óptica aos 15, 30, 45 e 60 dias de pós-operatório. Tanto na avaliação radiográfica como densitométrica não se observou diferença estatisticamente significante na evolução do calo ósseo entre os grupos (P>0,05. No presente estudo, o PRP autógeno combinado à hidroxiapatita não-absorvível não acelerou o processo de formação do calo ósseo, comparado à hidroxiapatita somente.The present study was aimed at evaluating the effects of autologous platelet-rich plasma (PRP in combination with unabsorbable hydroxyapatite on bone callus formation in an experimental canine diaphyseal radius fracture stabilized with bone plate. Eight mature, male and female mongrel dogs were selected weighed 5 to 15kg. Bone defects were created, bilateral, in both radii diaphysis, corresponding to 25% of bone diameter. On the right radius (group HA/PRP, the defect was filled with PRP and hydroxyapatite. On the left radius (group HA, was placed hydroxyapatite alone. PRP was obtain by a simplified technique using a laboratory

  11. Caracterização físico-mecânica de compósitos porosos de hidroxiapatita-titânia confeccionados pelo método da esponja polimérica Physical-mechanical characterization of hydroxyapatite-titanium oxide composites prepared by the polymeric sponge method

    Directory of Open Access Journals (Sweden)

    A. G. S. Galdino

    2012-09-01

    Full Text Available Ao longo das últimas décadas as biocerâmicas vem sendo utilizadas como materiais para reconstrução óssea, na qual a hidroxiapatita é uma das biocerâmicas mais utilizadas. Entretanto, a resistência mecânica da hidroxiapatita não é tão alta quando comparada com outras biocerâmicas. Este trabalho teve como objetivo fazer a caracterização físico-mecânica de compósitos de HA-TiO2 porosos. As amostras de HA-TiO2 foram confeccionadas pelo método da esponja polimérica nas proporções de 70% - 30%, 60% - 40% e 50% - 50% HA - TiO2, calcinadas a 550 ºC para retirada da esponja polimérica e sinterizadas a 1250 ºC, 1300 ºC e 1350 ºC. As amostras foram submetidas a ensaios mecânicos de compressão e dureza Vickers e a ensaios físicos de absorção de água, densidade aparente, retração linear de queima e porosidade aparente. Os resultados mostraram ser relativamente melhores quando comparados com os da hidroxiapatita, e estão de acordo com os encontrados na literatura.Bioceramics have been used as bone reconstruction materials in the last decades, hydroxyapatite being one of the most used for this purpose. However, the hydroxyapatite mechanical strength is not so high when compared to other bioceramics. This work aimed on characterizing physically and mechanically HA-TiO2 composites. Samples were prepared by the polymeric sponge method with 70% - 30% wt., 60% - 40% wt. and 50% - 50% wt. of HA - TiO2, calcined at 550ºC for sponge burning out and sintered at 1250 ºC, 1300 ºC and 1350 ºC. The samples were submitted to mechanical essays of compression and Vickers hardness and to physical essays of water absorption, apparent density, burning linear retraction and apparent density. Results showed relatively better than those of pure hydroxyapatite and they are in agreement with the literature.

  12. Avaliação pré-clínica de um material substituto ósseo xenógeno a base de hidroxiapatita/colágeno = Preclinical evaluation of a xenogenic hydroxyapatite/collagen-based bone substitute material

    Directory of Open Access Journals (Sweden)

    Bittencourt, Rafael Cotias

    2014-01-01

    Full Text Available Objetivo: O objetivo deste estudo foi avaliar as propriedades físicas, químicas e biológicas de um xenoenxerto bovino para o reparo ósseo. Métodos: Análise físico-química foi conduzida usando difração de raios X, espectroscopia no infravermelho por transformada de Fourier e microscopia eletrônica de varredura. Biocompatibilidade in vitro foi avaliada através de ensaios de citotoxicidade e adesão celular usando culturas de linhagem celular de fibroblastos e pré-osteoblastos murinos, respectivamente. Além disso, por ensaio in vivo usando enxertia subcutânea no modelo rato (5 e 10 semanas, hidroxiapatita sintética como material controle e ainda um experimento a longo prazo em defeitos de tamanho crítico em calvária (6 e 9 meses, coágulo sanguíneo e osso autógeno como controles negativo e positivo, respectivamente. Resultados: O material teste apresentou uma arquitetura tridimensional consistindo de grânulos densos e microporos (várias dimensões, composto de hidroxiapatita cristalina/fibras colágenas. O xenoenxerto foi citocompatível e após 7 dias foi observado espraiamento de pré-osteoblastos sobre grânulos do material. Análise histopatológica do material implantado no subcutâneo de ratos mostrou o xenoenxerto intato após 10 semanas circundado por tecido conjuntivo frouxo com suave infiltrado inflamatório e células gigantes multinucleadas ao redor de partículas (5 e 10 semanas similar à hidroxiapatita sintética. Considerando os defeitos de tamanho crítico em calvária foi observada 1,7 vezes mais formação de novo osso no xenoenxerto do que no grupo controle (P<0,001, um resultado similar verificado no autoenxerto. Não houve variação significante na densidade de volume do xenoenxerto (37,9%±4,3. Conclusão: Pode-se concluir que o material xenógeno é biomimético, biocompatível, osseocondutor e nãoreabsorvível, portanto sendo um material promissor para o reparo óss

  13. Application of the Rb-Sr, Pb-Pb and Sm-Nd systems on the Salobe 3A polymetallic deposit, Carajas Mineral Province, Para, Brazil; Aplicacao dos sistemas Rb-Sr, Pb-Pb e Sm-Nd do deposito polimetalico do Salobo 3A, Provincia Mineral de Carajas, Para

    Energy Technology Data Exchange (ETDEWEB)

    Mellito, Katia Maria

    1998-07-01

    The Salobo 3A polymetallic Cu (Au-Mo-Ag) deposit, located in the northern part of the Carajas Mineral Province, Para, consists of a metavolcano-sedimentary sequence represented by iron formation, amphibolite, schist and quartzite of the Igarape Salobo Group. This rock sequence rest uncomformably on the gneissic basement of the Xingu Complex. The copper mineralization hosted by iron formation consists of bornite-chalcocite and bornite-chalcopyrite disseminations associated with magnetite. The geochronological data determined through the application of the Rb-Sr, Sm-Nd and Pb-Pb methods, contribute to characterize the complex evolution of both the geological setting and the cupriferous mineralization of the Salobo deposit. The 3.11-2.92 Ga interval (T{sub DM}, Sm-Nd, whole rock) represents the age of the igneous protholith of the gneiss. The {epsilon}{sub Nd} values calculated for the time of the gneiss formation (2859 Ma) vary between +1.02 and -1.08, and indicate a short period between the mantle-crust differentiation epoch and the gneiss formation. Moreover, the {epsilon}{sub Nd} parameter suggest a mantle source with late crustal contamination. The application of the leaching technique allows a gradual extraction of Pb at each leaching step and it was applied to chalcocite and magnetite. The 2762 {+-} 180 Ma and 2776 {+-} 240 Ma ages determined on those minerals are interpreted to be close to the epoch of the formation of the copper mineralization with Uu and Th enrichment and of the iron formation deposition, respectively, in a conventional setting. The leaching technique was also applied to tourmaline from gneiss and quartzite, and the age near to 2400 Ma was attributed to its formation. The random variability of the Pb isotope compositions of the tourmaline together with its petrographic characteristics suggest the boron source is not associated with the metassedimentary rocks of the Igarape Salobo Group. The Sm-Nd mineral isochron attributed to schists

  14. Preparação de eletrodos de hidroxiapatita por diferentes metodologias de síntese e sua aplicação na determinação de fosfito em fertilizantes líquidos - DOI: 10.4025/actascitechnol.v30i2.5499

    Directory of Open Access Journals (Sweden)

    Josiane de Lima Souza

    2008-10-01

    Full Text Available A determinação de fosfito em fertilizantes líquidos é muito importante para o controle de qualidade destes produtos. Métodos clássicos de análise incluem principalmente metodologias gravimétricas ou espectrofotométricas que geram resíduos químicos tóxicos. Este trabalho descreve a construção de um eletrodo potenciométrico alternativo baseado em hidroxiapatita na determinação do fosfito. Uma resposta eletroquímica linear foi obtida para a concentração de fosfito entre os valores de 1 x 10-5 a 1 x 10-1 mol L-1. Os resultados obtidos pelo método proposto estão de acordo com aqueles obtidos pelo método gravimétrico ao nível de confiança de 95% para a determinação direta em fertilizantes líquidos.

  15. Caracterización de nuevos recubrimientos biocompatibles de hidroxiapatita-TiO2 obtenidos mediante Proyección Térmica de Alta Velocidad

    Directory of Open Access Journals (Sweden)

    Melero, H.

    2011-04-01

    Full Text Available Hydroxyapatite (HAp: Ca10(PO46OH2 is a biocompatible and bioactive ceramic material widely used as a coating on metal surfaces (dental implants, hip replacements ..., but the low adhesion between HAp and the substrate, due to differences in thermal expansion coefficients of both (very important in thermal spraying because of the fast cooling of the coating, which can produce a lost of adherence, and the degradation of HAp, have been tried to be improved through the incorporation of TiO2 to get a good combination of mechanical properties. Therefore, the objective of this project is to produce coatings of HAp 80% TiO2 and 20% (by weight on Ti6Al4V by High-Speed Thermal Spray (HVOF. The study of the microstructure has been carried out using scanning electron microscopy and characterization of the crystalline phases by X-ray diffraction and Raman spectrometry. The coatings adhesion has been measured by tensile tests according to ASTM C633-01 (2008, and their bioactivity also has been evaluated through its immersion in simulated body fluid (SBF, in order to measure their capacity to form an apatite layer on their surface.La Hidroxiapatita (HAp: Ca10(PO46OH2, es un material cerámico biocompatible y bioactivo muy empleado como recubrimiento sobre superficies metálicas (implantes dentales, prótesis de cadera…; sin embargo, la baja adherencia entre la HAp y el sustrato, debida a las diferencias entre los coeficientes de expansión térmica de ambos (a tener en cuenta en recubrimientos por proyección térmica ya que el enfriamiento posterior a la proyección puede producir una pérdida de adherencia o incluso la descohesión del recubrimiento y a la degradación de la HAp, se está intentado mejorar mediante la incorporación de TiO2, para obtener una buena combinación de propiedades mecánicas y biológicas. Por tanto, el objetivo de este trabajo es la obtención de recubrimientos de 80% de HAp y 20% de TiO2 (en peso sobre Ti6Al4V mediante

  16. Effect of the addition of collagen in the preparation of hydroxyapatite, aiming the application of pulp capping; Efeito da adicao de colageno na preparacao de hidroxiapatita visando a aplicacao como capeador pulpar

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, Geysy L.; Mendes, Luis C., E-mail: geysylopes@ima.ufrj.br [Instituto de Macromoleculas Professora Eloisa Mano (IMA) - Universidade Federal do Rio de Janeiro, UFRJ. Centro de Tecnologia, RJ (Brazil)

    2011-07-01

    This work studied the action of collagen (COLL) in the hydroxyapatite (HA) synthesis, produced through sol-gel process, in order to mimetize the chemical composition of dental tissue. The resulting material was characterized by energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction (WAXD) and scanning electron microscopy (SEM). The Ca/P ratio was determined through EDX - 1,89 e 2,38, with and without collagen, respectively. The FT-IR analysis showed no significant interaction between the constituents of the composite. The R-ray diffractograms indicated an increase of the resolution and intensity of the HA peak. The photomicrographies showed that the preparation method exhibited significantly influence onto the hydroxyapatite morphology, as well as resulted in a homogeneously dispersed composite. (author)

  17. Determination of strontium isotopic composition in natural waters: examples of application in subsurface waters of the coastal zone of Bragantina region, Para, BR; Determinacao da composicao isotopica de estroncio em aguas naturais: exemplos de sua aplicacao em aguas subsuperficiais da zona costeira na regiao Bragantina-PA

    Energy Technology Data Exchange (ETDEWEB)

    Bordalo, Adriana Oliveira; Moura, Candido Augusto Veloso; Scheller, Thomas [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Centro de Geociencias]. E-mail: adriana@ufpa.br

    2007-07-15

    Analytical procedures used for determining the concentrations and isotope composition of strontium in subsurface waters, by mass spectrometry, are described. Sampling was performed in coastal plateaus, salt marsh and mangrove environments in the coastal region of Para. Coastal plateau waters have {delta}{sup 87}Sr between 1.51 and 6.26 per mille and Sr concentration bellow 58 ppb. Salt marsh waters show {delta}{sup 87}Sr between 0.55 and 0.90 per mille and Sr concentration between 93 and 114 ppm, while mangrove waters have {delta}{sup 87}Sr per mille around zero and Sr concentration above 15 ppm. Differences in the {sup 87}Sr/{sup 86}Sr ratio in these subsurface waters are detected, as well as seasonal variations in the coastal plateau waters. (author)

  18. Hidroxiapatita porosa produzida através do gelcasting de espumas visando aplicações biomédicas Porous hydroxyapatite prepared by gelcating of foams for biomedical applications

    Directory of Open Access Journals (Sweden)

    P. Sepúlveda

    1999-12-01

    Full Text Available Hidroxiapatita porosa foi produzida por meio de uma nova técnica de processamento, visando aplicações na área de implantes ósseos. A produção do material poroso é feita através da produção de espumas pela agitação de suspensões cerâmicas aquosas contendo tensoativos adequados. A solidificação que segue é obtida pela adição de reagentes iniciadores da polimerização in situ de monômeros orgânicos, inicialmente incluídos nas composições, formando um gel. Este método permite a produção de corpos com formatos de alta complexidade e elevada resistência mecânica com níveis de porosidade próximos de 90%vol, que suportam corte e torneamento no estado a verde. Os aditivos orgânicos são eliminados a 300 °C e sinterização a 1350 °C é efetuada para consolidação da matriz. A otimização da resistência mecânica decorre da combinação entre uma matriz cerâmica de alta densidade a uma estrutura de poros esféricos com diâmetros que variam de 20-1000 mm possuindo inter-conecções de aproximadamente 10-100 mm, dependendo da densidade. O material sinterizado foi avaliado quanto a sua citoxicidade, utilizando-se o método quantitativo de formação de colônias que calcula o índice de citotoxicidade IC50(% após contato do extrato do material com células de mamíferos. Os resultados mostraram que o processo de fabricação e os reagentes utilizados não afetaram os baixos níveis de toxicidade do pó de hidroxiapatita que era originalmente de pureza biomédica.A novel technique has been applied to manufacture porous hydroxyapatite for implant applications. The process involved generation of foam from an aqueous suspension of the powder followed by in situ polymerisation of organic monomers, which had been previously added to the compositions. This method produces strong gelled and complex-shaped bodies with up to 90% porosity that can withstand machining in the green state. The organic additives are eliminated at

  19. Estudio de la capacidad de los hidroxiapatitos como reactivos para la eliminación de metales

    OpenAIRE

    Toribio Jiménez, Eva

    2015-01-01

    El Trabajo de Fin de Grado se ha centrado en el estudio de la capacidad que tienen los hidroxiapatitos, como materiales reactivos para eliminar metales de disoluciones acuosas. En el mismo, se evaluaran diferentes formas de hidroxiapatitos, tanto sintetizados siguiendo rutas a alta temperatura y a temperatura ambiente, así como un tipo de hidroxiapatita natural de origen animal y se han elegido dos metales pesados de interés ambiental, bien por su impacto sobre la salud humana o sobre los ...

  20. Surface topography of hydroxyapatite affects ROS17/2.8 cells response A topografia de superfície da hidroxiapatita afeta a resposta de células ROS17/2.8

    Directory of Open Access Journals (Sweden)

    Adalberto Luiz Rosa

    2002-09-01

    Full Text Available Hydroxyapatite (HA has been used in orthopedic, dental, and maxillofacial surgery as a bone substitute. The aim of this investigation was to study the effect of surface topography produced by the presence of microporosity on cell response, evaluating: cell attachment, cell morphology, cell proliferation, total protein content, and alkaline phosphatase (ALP activity. HA discs with different percentages of microporosity (A hidroxiapatita (HA tem sido utilizada como revestimento de implantes e para substituição de tecido ósseo. O objetivo deste estudo foi avaliar o efeito da topografia de superfície da HA, resultante da presença de microporosidade, sobre a adesão, a morfologia e proliferação celulares, a medida de proteína total e a atividade de fosfatase alcalina. Discos de HA com diferentes porcentagens de microporosidade (< 5%, 15% e 30% foram fabricados por uma combinação das técnicas de pressão uniaxial e sinterização. Células ROS17/2.8 foram cultivadas sobre os discos de HA. Para a adesão, as células foram cultivadas por duas horas. A morfologia foi avaliada após sete dias. A proliferação, medida de proteína total e atividade de ALP foram avaliadas após sete e quatorze dias. Os dados foram comparados por ANOVA e teste de Duncan quando apropriado. A adesão (p = 0,11 e a medida de proteína total (p = 0,31 não foram afetadas pela topografia de superfície. A proliferação após sete e quatorze dias (p = 0,0007 e p = 0,003, respectivamente, e a atividade de ALP (p = 0,0007 foram significantemente menores na superfície irregular (HA30. Esses resultados sugerem que eventos iniciais não são afetados pela topografia, enquanto superfícies com topografias mais regulares (microporosidade de 15% ou menos favoreceram eventos intermediários e finais, como proliferação e atividade de ALP.

  1. New zirconium alloys for nuclear application; Novas ligas de zirconio para aplicacao nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Lobo, R.M.; Andrade, A.H.P., E-mail: rmlobo@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2010-07-01

    Zirconium alloys are widely used in the nuclear industry, mainly in fuel cladding tubes and structural components for PWR plants. The service life of these components, which operate under high temperatures conditions ({approx} 300 deg C), has led to developing new alloys with the aim to improve the mechanical properties, corrosion resistance and irradiation damage. The variation in the composition of the alloy produces second phase particles which alter the materials properties according to their size and distribution, is essential therefore, knowledge their characteristics. Analysis of second phase particles in zirconium alloys are carried out by scanning electron microscopy, transmission electron microscopy and image analysis. This study used the zircaloy-4 to illustrate the characterization of these alloys through the study of second phase particles. (author)

  2. Estudo da topografia e da osseointegração de implante de titânio sob ação do LASER, com ou sem deposição de hidroxiapatita, em coelhos

    OpenAIRE

    Sisti, Karin Ellen

    2011-01-01

    Objetivo: Estudar a topografia a osseointegração de implantes de titânio sob ação do LASER de alta intensidade com e sem deposição química de hidroxiapatita, em coelhos. Método: Foram utilizados 30 coelhos albinos que receberam em suas tíbias 3 tipos de superfície de implantes: grupo controle(GI) implantes usinados, grupo(GII) irradiado LASER(Yb), e grupo irradiado e depositado hidroxiapatita pelo método biomimético(GIII). Após os períodos de avaliações (30 e 60 dias) os implantes foram subme...

  3. Reparación de fracturas de suelo orbitario con hidroxiapatita HAP-200 Repair of orbital floor fractures with HAP-200 hydroxyapatite

    Directory of Open Access Journals (Sweden)

    Juan Carlos Quintana Díaz

    2005-12-01

    Full Text Available Se realizó un estudio clínico y radiográfico pre y posoperatorio en 4 pacientes con fracturas del suelo orbitario reparadas con hidroxiapatita HAP-200. En ninguno de los pacientes se encontró reacción adversa ante este material implantalógico y sí muy buena tolerancia y adaptabilidad, lo que nos reafirmó su alta biocompatibilidad, por lo que lo recomendamos en el tratamiento de esta afección.A pre- and postoperative clinical and X-ray study was conducted in 4 patients with orbital floor fractures repaired with HAP-200hydroxyapatite. . No adverse reaction to this material was observed in any of the patients, who showed a good tolerance and adaptability that confirmed its high biocompatibility and make it recommendable for treating this affection.

  4. Preparação de eletrodos de hidroxiapatita por diferentes metodologias de síntese e sua aplicação na determinação de fosfito em fertilizantes líquidos = Different synthesis methods for hydroxyapatite-based electrodes and their application in phosphite determination in fertilizing products

    Directory of Open Access Journals (Sweden)

    Josiane de Lima Souza

    2008-07-01

    Full Text Available A determinação de fosfito em fertilizantes líquidos é muito importante para o controle de qualidade destes produtos. Métodos clássicos de análise incluem principalmente metodologias gravimétricas ou espectrofotométricas que geram resíduos químicos tóxicos. Este trabalho descreve a construção de um eletrodo potenciométrico alternativo baseado em hidroxiapatita na determinação do fosfito. Uma resposta eletroquímica linear foi obtida paraa concentração de fosfito entre os valores de 1 x 10-5 a 1 x 10-1 mol L-1. Os resultados obtidos pelo método proposto estão de acordo com aqueles obtidos pelo método gravimétrico ao nível de confiança de 95% para a determinação direta em fertilizantes líquidos. Phosphite determination in fertilizing products is very important for the quality control of these products. Classical methods of analysis include gravimetric or spectrophotometric methodologies, which create toxic chemical residues. This paper describes an alternative hydroxyapatite-based electrode for phosphite determination. Alinear electrochemical response was obtained from a phosphite concentration of 1 x 10- 5 to 1 x 10-1 mol L-1. The results obtained the by proposed method are in accordance with those obtained by the gravimetric method at a 95% confidence level for directdetermination in liquid fertilizing products.

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

    Directory of Open Access Journals (Sweden)

    E. P. Avés

    2008-12-01

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

  6. Síntese e caracterização do material hidrotalcita-hidroxiapatita dopado com nanotubos de carbono e sua aplicação na catálise da reação de transesterificação

    Directory of Open Access Journals (Sweden)

    E. Rodrigues

    Full Text Available Resumo Este trabalho teve por objetivo a síntese e caracterização do material hidrotalcita-hidroxiapatita (HTHAp dopado com três diferentes proporções (1, 5 e 15% p/p de nanotubos de carbono (NTC a fim de avaliar seu potencial como catalisador heterogêneo na reação de metanólise do óleo de soja. A síntese do material HTHAp foi realizada pelo método de coprecipitação (10≤pH≤11 com homogeneização ultrassônica e tratamento hidrotérmico a 80 °C. DRX, MEV/EDS, FT-IR, Raman, fisissorção de N2 e TG/DTA foram as técnicas de caracterização utilizadas. A amostra HTHAp1NTC, dopada a 1% p/p, foi testada como catalisador em duas condições de temperatura (180 e 240 °C, 4 h de tempo de reação, carga de 2,5% de catalisador e razão álcool:óleo de 12:1. A dopagem contribuiu para melhorar propriedades estruturais, morfológicas e a estabilidade térmica do material. Os resultados de rendimento obtidos de 35,2% (180 °C e 40,5% (240 °C qualificam o material HTHAp dopado com NTC como catalisador em potencial na reação de transesterificação.

  7. Osseointegração clínica-radiológica do compósito hidroxiapatita-lignina entre implante metálico e tecido ósseo em coelho Clinical-radiographic osseointegration of hydroxyapatite-lignin composite between metallic implant and bone tissue in rabbit

    Directory of Open Access Journals (Sweden)

    M.M. Martinez

    2009-08-01

    Full Text Available Para avaliar o compósito hidroxiapatita-lignina na osseointegração entre implante metálico e o tecido ósseo, foram utilizados 20 coelhos adultos, nos quais foi realizada uma falha óssea na face lateral proximal de ambas as tíbias. Na tíbia esquerda, introduziu-se, no canal medular, um pino intramedular de Schanz revestido com o compósito em sua parte rosqueada, após o preenchimento daquele com 1000mg do compósito. A falha cortical foi preenchida com o compósito. O mesmo foi feito na tíbia direita, porém sem a utilização do compósito, servindo como controle. A avaliação clínica baseou-se na deiscência, claudicação, sensibilidade dolorosa e circunferência tibial. Foram realizadas radiografias imediatamente após a cirurgia e aos oito, 30, 60, 90 e 120 dias do pós-operatório. A maioria dos animais apresentou evolução clínica normal. Nas radiografias do grupo tratado, houve decréscimo da radiopacidade no defeito e no espaço medular até tornar-se semelhante à do osso circunvizinho, quadro inverso ao do grupo-controle. Conclui-se que o compósito hidroxiapatita-lignina não mostrou indícios clínicos de rejeição e que o tecido visualizado na altura da falha óssea e ao redor do pino intramedular tinha radiopacidade semelhante à do osso circunvizinho, o que sugere que o material promoveu a integração com o tecido ósseo.This study evaluated a sinthetic hydroxyapatite-lignin composite for osseoingration between metallic implant and bone tissue. Twenty New Zealand rabbits were used. A defect was made a the proximal region of lateral surfaces of both tibias. An intramedullary pin was inserted in the medullary cavity of the left tibia after filling the cavity with 1,000mg of the composite and covering the thread part of the pin with the composite. The same procedure was made in control tibias without the composite. Clinical evaluation was based on inflammatory reaction, dehiscence, lameness, pain, and tibial

  8. Cementos óseos acrílicos modificados con hidroxiapatita/acetato de vinilo: caracterización mecánica, termoanálitica y bioactividad in vitro Acrylic bone cement modified whit hydroxiapatyte/vinyl acetate: mechanical, thermoanalytical characterization and in vitro bioactivity

    Directory of Open Access Journals (Sweden)

    Nayrim B. Guerra

    2010-06-01

    Full Text Available Los cementos óseos se han convertido en los últimos años en biomateriales de gran utilidad en la fijación de prótesis y en la reconstrucción del hueso. El objetivo de este trabajo es evaluar las propiedades termoanalíticas tales como temperatura máxima de polimerización y tiempo de fraguado en cementos óseos acrílicos modificados con hidroxiapatita/acetato de vinilo, determinar la resistencia a la compresión axial y realizar ensayos de bioactividad in vitro. Diferentes contenidos de acetato de vinilo fueron incorporados en cementos óseos acrílicos cargados todos con un 30 % de hidroxiapatita CORALINA® HAP-200. Las propiedades mecánicas y los parámetros de curado fueron evaluados cumpliendo lo establecido en la Norma ISO 5833 descrita para cementos óseos acrílicos. Se determinaron los parámetros termoanalíticos, obteniéndose tiempos de fraguados entre 3 y 6 minutos y los valores de temperaturas máximas de polimerización oscilan entre 66 y 88 °C. Se obtuvo formulaciones con valores de resistencia a la compresión superiores a lo establecido en la Norma ISO 5833. Se demostró la bioactividad de las formulaciones mediante la inmersión de las muestras en fluido biológico simulado, observándose en la superficie de las mismas la nucleación y el crecimiento de cristales con morfología similar a las apatitas biológicas.Bone cements have become biomaterials of great utility in the prosthesis fixation and as substitutes to the bone. The objective of this study is to evaluate the thermo analytical properties such as setting time and peak temperature of polymerization of acrylic bone cement modified with hydroxyapatite/vinyl acetate, to determine the compression strengths and perform in vitro bioactivity tests. Amounts of vinyl acetate component were incorporated in different percentages in acrylic bone cements, all loaded with 30 % of hydroxyapatite CORALINA® HAP-200. Curing parameters and mechanical properties were

  9. EVALUACIÓN DEL COMPORTAMIENTO IN VITRO DE RECUBRIMIENTOS DE HIDROXIAPATITA DEPOSITADOS MEDIANTE PROYECCIÓN TÉRMICA POR COMBUSTIÓN OXIACETILÉNICA SOBRE UN SUSTRATO DE Ti6Al4V

    Directory of Open Access Journals (Sweden)

    HAMILTON COPETE

    2013-01-01

    Full Text Available Recubrimientos de Hidroxiapatita sintética producida por precipitación y calcinación a 850 °C fueron depositados sobre sustratos de Ti6Al4V mediante proyección térmica por combustión. Las fases presentes en el material sintetizado y en los recubrimientos elaborados fueron determinadas mediante Difracción de Rayos X. Los recubrimientos fueron evaluados en condiciones in vitro con fluido fisiológico a 37 °C que simula el plasma humano, por periodos de 3, 7, 15 y 30 días. La superficie de los recubrimientos fue caracterizada antes y después de los ensayos in vitro mediante Microscopía Electrónica de Barrido y por Barrido de Energía Dispersiva. La concentración de iones de fosfato y de calcio en el fluido fisiológico fue determinada mediante espectrofotometría. Los resultados de las pruebas in vitro sugieren la acción de dos mecanismos: disolución del recubrimiento en el fluido fisiológico y posterior precipitación de cristales de calcio y fósforo sobre la superficie de la capa de Hidroxiapatita.

  10. Utilización de la hidroxiapatita en cirugía maxilofacial: Actualización bibliográfica

    Directory of Open Access Journals (Sweden)

    Juan Carlos Quintana Díaz

    1998-04-01

    Full Text Available Resumen: Se presenta una revisión de la literatura internacional actualizada, así como algunas experiencias en nuestro país sobre la actualización de la hidroxiapatita en diferentes afecciones maxilofaciales. Se exponen resultados muy relevantes con este material implantológico altamente compatible con el tejido óseo como en el aumento de rebordes alveolares atróficos, en la preservación de rebordes alveolares, en la cirugía ortognática, en la traumatología, en la cirugía de camuflaje y como relleno de zonas osteolíticas creadas por quistes y tumores. Se detallan los avances logrados en la implantalogía luego de aparecer este material después de la década de los 70, por las ventajas que ofrece a diferencia de otros materiales anteriormente utilizados.A review of updated international literature as well as some domestic experiences on the use of hydroxiapatite in different maxillofacial affections is presented. Very relevant results obtained from the use of this highly compatible implant material in the atropied alveolar ridge augmentations, the preservation of alveolar ridges, the orthognatic surgery, the traumatology, the camouflage surgery and the filling of osteolytic areas created by cysts and tumors are reflected. The advances made in the implanting technique upon the emergence of this material after the 70’s are detailed since hydroxiapatite provides differents from other used materials.

  11. Influencia de la temperatura en la compactación hidrotérmica en caliente de polvos de magnesio hidroxiapatita

    Directory of Open Access Journals (Sweden)

    Epsylon Erydani Mejía-Martínez

    2018-03-01

    Full Text Available Resumen: Compactados de hidroxiapatita estequiométrica (HAp y solución sólida de magnesio hidroxiapatita (Mg-HAp fueron preparados mediante la técnica de compactación hidrotérmica en caliente (CHC, a diferentes temperaturas (150, 175 y 200 °C, utilizando una presión de carga uniaxial de 60 MPa durante 6 h, con la adición del 10% en peso de agua desionizada. El material de partida fue obtenido mediante síntesis hidrotérmica a 150 °C durante 10 h. Los productos compactados fueron caracterizados química, física y mecánicamente. De acuerdo con el análisis de resultados, se determinó que un incremento en la temperatura de CHC favoreció la reacción entre las partículas de HAp o Mg-HAp y el agua promoviendo fases con mayor grado de cristalinidad, sin generar subproductos o alteraciones estructurales. Este resultado es particularmente relevante, ya que durante la CHC se produce un empaquetamiento efectivo de las partículas, activado por el mecanismo de disolución-recristalización en presencia del agua, con lo cual se logró una densificación del orden del 70%. Los compactados de HAp y Mg-HAp obtenidos a 200 °C, con porosidad abierta del orden del 30-36%, mostraron valores de máxima densidad aparente de 3,085 ± 0,138 g/cm3 y 2,792 ± 0,021 g/cm3, respectivamente, con una máxima resistencia a la tensión de 7,10 ± 0,20 y 5,89 ± 0,06 MPa. De acuerdo a estos resultados, el material obtenido podría ser utilizado en aplicaciones ortopédicas y/u odontológicas. Abstract: Preparation of hydrothermal hot-pressed (HHP compacts of the stoichiometric hydroxyapatite and solid-solution of magnesium hydroxyapatite powders (HAp and Mg-HAp was carry out at different temperatures 150, 175 and 200 °C, using uniaxial pressure load of 60 MPa for 6 h, with the addition of 10% wt. of deionized water as a solvent. The starting powders were obtained by hydrothermal synthesis at 150 °C for 10 h. The HHP compacts were

  12. Processing of hydroxyapatite obtained by combustion synthesis; Procesamiento de hidroxiapatita obtenida mediante síntesis por combustión

    Energy Technology Data Exchange (ETDEWEB)

    Canillas, M.; Rivero, R.; García-Carrodeguas, R.; Barba, F.; Rodríguez, M.A.

    2017-11-01

    One of the reasons of implants failure are the stress forces appearing in the material–tissue interface due to the differences between their mechanical properties. For this reason, similar mechanical properties to the surrounding tissue are desirable. The synthesis of hydroxyapatite by solution combustion method and its processing have been studied in order to obtain fully dense ceramic bodies with improved mechanical strength. Combustion synthesis provides nanostructured powders characterized by a high surface area to facilitate the following sintering. Moreover, synthesis was conducted in aqueous and oxidizing media. Oxidizing media improve homogenization and increase the energy released during combustion. It gives rise to particles whose morphology and size suggest lower surface energies compared with aqueous media. The obtained powders were sintered by using a controlled sintering rate schedule. Lower surfaces energies minimize the shrinkage during sintering and relative densities measurements and diametral compression test confirm improved densification and consequently mechanical properties. [Spanish] Una de las razones principales de fracaso de los implantes son las fuerzas de estrés que aparecen en la interface material-tejido debido a las diferencias existentes entre sus propiedades mecánicas. Por esta razón, es necesario que el implante posea propiedades mecánicas similares a las del tejido circundante. La síntesis de hidroxiapatita por el método de combustión y su procesamiento se han estudiado con el objetivo de obtener cuerpos cerámicos completamente densificados y, consecuentemente, con propiedades mecánicas mejoradas. El método de combustión provee de polvos nanoestructurados que se caracterizan por una superficie específica elevada que facilita el siguiente proceso de sinterización. Además, este proceso de síntesis se ha realizado en medio acuoso y oxidante. El medio oxidante homogeniza e incrementa la energía liberada durante la

  13. Chitosan-based films composites for wound healing purposes; Filmes compositos de quitosana para aplicacao no revestimento de ferimentos

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Natali de O.; Silva, Gabriela T. da; Schulz, Gracelie A.S.; Fajardo, Andre R., E-mail: natalioliveiraalves@gmail.com [Universidade Federal de Pelotas (LaCoPol/UFPel), Pelotas, RS (Brazil). Centro de Ciencias Quimicas, Farmaceuticas e de Alimentos. Lab. de Tecnologia e Desenvolvimento de Compositos e Materiais Polimericos

    2015-07-01

    Chitosan has been extensively applied in the developing of biomaterials due to its desirable good physico-chemical and biological properties. According to this, here films composite of chitosan, poly(vinyl alcohol) and bovine bone powder were prepared by casting willing to be applied in wound healing purposes. Moreover, the first step was the developing of a suitable method to obtain bovine bone powder, which was utilized here as filler. All the materials and films were fully characterized by FTIR, DRX and thermal analysis. Water uptake capacity was measured by swelling assays. (author)

  14. Calcium aluminates potential for endodontics and orthopedics applications; Aluminatos de calcio e seu potencial para aplicacao em endodontia e ortopedia

    Energy Technology Data Exchange (ETDEWEB)

    Santos, G.L. dos; Andrade, T.L.; Oliveira, I.R., E-mail: ivonero@univap.br [Universidade do Vale do Paraiba (UNIVAP), Sao Jose dos Campos, SP (Brazil); Pandolfelli, V.C. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil)

    2011-07-01

    The mostly used material in the areas of endodontics (MTA, mineral trioxide aggregate) and bone reconstruction (PMMA, polymethyl methacrylate) present some limiting properties requiring thus changes in their compositions as well as the development of alternative materials. In this context, a novel biomaterial-based calcium aluminate cement (CAC) has been studied in order to keep the positive properties and clinical applications of MTA and PMMA, overcoming some their disadvantages. Recent studies involving the use of CAC are based on commercial products consisting of a mixture of phases. Improvements can be attained by searching the synthesis routes of CAC aiming the proper balance between the phases and the control of impurities that may impair its performance in applications in the areas of health. By the optimization of the CAC phases production, this article aims to present their characterization based on hydration temperature; working time and setting time; pH, ions solubilization and dissolution in contact with water and different solutions of simulated body fluid. The results indicated the CA phase as the most suitable for application in the areas of health. (author)

  15. Neural network application for illicit substances identification; Aplicacao de redes neurais para a identificacao de substancias ilicitas

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Wallace V.; Silva, Ademir X. da; Crispim, Verginia R.; Schirru, Roberto [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear

    2000-07-01

    Thermal neutron activation analysis is based on neutron capture prompt gamma-ray analysis and has been used in wide variety of fields, for examples, for inspection of checked airline baggage and for detection of buried land mines. In all of these applications, the detected {gamma}-ray intensities from the elements present are used to estimate their concentrations. A study about application using a trained neutral network is presented to determine the presence of illicit substances, such as explosives and drugs, carried out in the luggages. The illicit substances emit characteristic detected {gamma}-ray which are the fingerprint of each isotope. The fingerprint data-base of the gamma-ray spectrum of substances is obtained via Monte Carlo N-Particle Transport code, MCNP, version 4B. It was possible to train the neural network to determine the presence of explosives and narcotics even hidden by several materials. (author)

  16. Application of gamma irradiation technique for the preservation of propolis; Aplicacao da tecnica de irradiacao gama para preservacao de propolis

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Andrea Harumi

    2002-07-01

    Irradiation has been recognized as an efficient method for the reduction of deteriorating and pathogenic microorganisms in foods. Propolis is a resinous product made by bees from material processed by the bee's own metabolism and resins from plants. The aim of this work was the application of gamma irradiation technique for the preservation of propolis, because of its efficiency in the reduction of the microbial load. The changes on the total flavonoids content, phenolic compounds and other characteristics required for the qualification and characterization of Brazilian propolis were also analysed. Propolis samples from Juiz de Fora region, Minas Gerais, were irradiated in a {sup 60}Co source, with doses from 0 to 10kGy for the microbiological analyses and 5.0, 7.0 and 10.0kGy for the physico-chemical analyses. The physico-chemical that have been made were: determination of total flavonoids content, semi-quantitative determination of phenolic compounds (artepelin-C, kempferol, chrysin, galangin and quercetin), dry matter analysis, humidity, ash content, mechanical mass and waxes. The ionizing radiation has shown to be efficient in the reduction of the microbial load. Total coliforms determination showed a great reduction with the dose of 3kGy and concerning mesophile aerobic bacteria a systematic reduction was observed, achieving values <10 UFC/g for the dose of 10kGy; similar results was obtained for molds and yeasts. Salmonella assays were negative for all samples. There was no significant alteration on total flavonoids contents nor on the composition of phenolic compounds as a consequence of radiation application at the assayed conditions. The complementary analyses of dry matter and humidity contents, ashes, mechanical mass and waxes did not shown changes after irradiation even with the maximum dose of 10kGy, remaining the results within the standards required by the Brazilian legislation. (author)

  17. Application of fractional control techniques in petrochemical process; Aplicacao de tecnicas de controle fracionario para processos petroquimicos

    Energy Technology Data Exchange (ETDEWEB)

    Isfer, Luis A.D.; Lenzi, Marcelo K. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil); Lenzi, Ervin K. [Universidade Estadual de Maringa (UEM), PR (Brazil)

    2008-07-01

    This work deals with the study of petrochemical process modeling and control using fractional differential equations. This kind of equation has been successfully used in modeling/identification, due to its powerful phenomenological description capability, generalizing conventional/classical models commonly used. Experimental data from literature were used for process identification and the mathematical model obtained, based on fractional differential equations, was the study of servo closed-loop control. Owing to its simplicity, the proportional type controller was used for this task, being able to control the process, keeping its stability, despite off-set. Different controller gains were used for simulation purposes, indicating that the higher the value of K{sub c}, the lower the off-set. (author)

  18. Use of TANDEM methodology for quality control in radiation protection; Aplicacao de metodologia TANDEM para controle de qualidade em radioprotecao

    Energy Technology Data Exchange (ETDEWEB)

    Mello, O.A.; Oliveira, I.R.; Leyton, F.; Nogueira, M.S., E-mail: mnogueira@cdtn.br [Centro de Desenvolvimeto da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Borges, F.L.S., E-mail: flavialuizaborges@yahoo.com.br [Vigilancia Sanitaria de Minas Gerais, Belo Horizonte, MG (Brazil); Joana, G.S., E-mail: georgia.joana@gmail.com [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil)

    2014-07-01

    Recent studies have indicated the increase of the incidence of lens opacities for low radiation doses. Considering epidemiological data, the International Commission on Radiological Protection (ICRP) issued a statement that changed the absorbed dose threshold for the eye lens. The statement also recommends a reduction in the dose limits to the eye lens for occupationally exposed persons; now it is considered to be 20 mSv in a year averaged over five years. For this research two types of thermoluminescent dosimeters TL were used in the construction of the curve tandem. (LiF-100H e LiF-200). For system calibration three monitors were irradiated for each radiation beam. The monitors were irradiated with 4 mGy kerma at 1.5 m from the focal point. The Tandem curve was obtained by the ratio between the values of the energy dependence curves of each dosimeter. Data obtained for the corresponding x-ray beams to radiation reference N60 to N120 are more accurate for determining the energy - steepest part of the curve. The results are shown similar to similar studies and confirm the possibility of using the method for determining the unknown energy radiation fields. (author)

  19. Hidroxiapatita e quitosana isoladas e associadas à medula óssea no reparo do tecido ósseo em coelhos. Estudo histológico e morfométrico

    Directory of Open Access Journals (Sweden)

    Adílio Santos de Azevedo

    2013-07-01

    Full Text Available O objetivo do presente trabalho foi avaliar o processo de regeneração óssea em coelhos através da utilização da hidroxiapatita e da quitosana isoladas e associadas à medula óssea. Foram utilizados 20 coelhos adultos, de ambos os sexos, da raça Nova Zelândia e pesando em média 3,0±0,4kg. Os animais foram divididos ao acaso de acordo com dois momentos experimentais, sendo que 10 animais foram submetidos à eutanásia 30 dias após a cirurgia, e 10, 60 dias após a cirurgia. Foram utilizados quatro implantes que constituíram os grupos. Os materiais foram introduzidos em defeitos criados cirurgicamente na metáfise proximal (MP e distal (MD de cada fêmur, de modo que a quitosana foi introduzida na MP e a hidroxiapatita na MD do membro esquerdo e, no membro direito, além dos implantes, foi adicionada medula óssea. Na avaliação histológica descritiva comparativa, constatou-se que os grupos QUI e QUIMO, em ambos os momentos estudados, estimularam reações mais acentuadas e aceleraram o reparo ósseo. Na análise morfométrica, os grupos QUI e QUIMO diferiram estatisticamente dos outros grupos, tendo sido observada maior formação óssea (P<0,05.

  20. Criteria for design and application of city-gates heaters; Criterio para aplicacao e dimensionamento de aquecedores para pontos de entrega de gas

    Energy Technology Data Exchange (ETDEWEB)

    Henrique, Reis dos Reis Rodrigues; Machado, Leandro Bastos; Passos, Ney Goncalves; Correia, Luiz de Carvalho Dias [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2005-07-01

    Gas delivery pressures foreseen in supplying contracts with LDS's (local distribution companies) require the adoption of pressure regulating systems in city-gates, which are installations where gas custody is transferred from the shipper to the LDC's. Generally, pressure drop is such that causes a large decrease in temperature gas. This temperature drop, depending on how large it is, may be not allowable, for it would imply in materials weakening and also in hydrocarbons hydrates formation. For this reason, many city-gates design contemplate a heating system, upstream the pressure regulation system, in order to warrant an acceptable temperature range of the delivering gas. The fact that heating systems represent roughly 30% of material costs of city-gates has motivated an accurate study of current practices of design and application of those systems. This paper presents these study results, as a criteria proposal that will allow city-gates reduction costs, both CAPEX and OPEX, at a very propitious time, considering that Brazilian gas industry is going to have a great expansion in the next years. (author)

  1. Crioterapia no pos-parto: tempo de aplicacao e mudancas na temperatura perineal

    Directory of Open Access Journals (Sweden)

    Adriana Amorim Francisco

    2013-06-01

    Full Text Available Estudo descritivo com dados de dois ensaios clínicos realizados em 2008 e 2009 em uma maternidade de uma instituição filantrópica da cidade de São Paulo. Teve como objetivo descrever a temperatura perineal após a aplicação de bolsa de gelo no pós-parto normal. Três grupos com 38 puérperas cada (n=114 receberam aplicação perineal de bolsa de gelo entre 2 e 48h após o parto. Os achados indicaram que com 10 min de crioterapia as médias da temperatura perineal atingiram de 13,3 a 15,3oC, com pequena redução de temperatura ao final de aplicações de 15 e 20 minutos (2,4 e 2,7o, respectivamente. Após resfriamento por 10 min., as mulheres referiram frio e alívio e, depois de 15 a 20 min., dormência e anestesia local. Conclui-se que 10 minutos de aplicação foram suficientes para reduzir a temperatura perineal aos níveis recomendados para analgesia (10-15oC.

  2. Comparação entre os bioenxertos de hidroxiapatita de cálcio e submucosa de intestino delgado porcino no preenchimento de defeitos ósseos criados em mandíbula de ratos Defect repair in rat mandible with hydroxyapatite cement comparad to small intestine submucosa

    Directory of Open Access Journals (Sweden)

    Andréa Thomaz Soccol

    2006-04-01

    Full Text Available OBJETIVO: O objetivo do presente estudo consiste em avaliar a regeneração óssea em defeito criado na mandíbula de ratos utilizando dois bioenxertos: hidroxiapatita de cálcio sintética e submucosa de intestino delgado porcina. FORMA DE ESTUDO: Experimental randomizado. MATERIAL E MÉTODO: Foram utilizados 24 ratos da linhagem Wisthar-Furth. Um defeito ósseo de 0,75cm x 1,5cm no corpo de cada hemimandíbula foi realizado em todos os animais com broca esférica de baixa rotação. Padronizou-se à esquerda o preenchimento do defeito ósseo, no grupo I com 15 microgramas de hidroxiapatita e no grupo II com preenchimento de submucosa de intestino delgado porcina (SID, e à direita o não-preenchimento serviu como controle. A eutanásia foi realizada no 40° dia de pós-operatório, após a qual se procederam as análises macroscópicas e histológicas das peças. RESULTADOS: O comprimento médio em milímetros das hemimandíbulas do grupo hidroxiapatita foi de 3,75, e o do grupo SID 3,03 e o do grupo controle foi de 2,63 (p: 0,0022. No grupo hidroxiapatita a neoformação óssea perfez uma área correspondente à 76,64% do total já no grupo SID 63,64% do total. CONCLUSÃO: Os resultados macroscópios e microscópicos foram superiores com a utilização do enxerto de hidroxiapatita quando comparado ao grupo submucosa de intestino delgado porcino. Entretanto os dois bioenxertos mostraram-se osteoindutores quando comparados ao controle.AIM: The aim of this study was to evaluate the bone formation in surgically created defects of rabbit mandibles by synthetic hydroxyapatite of calcium compared to small Intestine Submucosa. MATERIAL AND METHOD: 24 mices lineage Wisthar-Furth were used. A bony defect of 0,75 cm x 1,5 cm in mandibular ramus was accomplished in all animals. The hydroxyapatite implants were placed on the left hemimandiblein groupI, small Intestine submucosa in group II, and the right served as control. The euthanasia was accomplished

  3. Matriz para ingeniería de tejido óseo: modificación superficial con zinc. Estudio preliminar. [Scaffold for bone tissue engineering: superficial modification with zinc. Preliminary study

    Directory of Open Access Journals (Sweden)

    Cristian Martínez

    2013-09-01

    Full Text Available El objetivo del presente trabajo es desarrollar un método de síntesis de matrices para ingeniería de tejidos, capaces de acelerar los procesos reparativos y disminuir el riesgo de infección, destinadas a cirugías reconstructivas que involucren el tejido óseo. A este fin se emplea la fase mineral de hueso bovino, la hidroxiapatita, conservando su estructura tridimensional. Esta se obtiene a partir de un proceso de lavado químico, seguido de un proceso térmico que elimina todos los componentes orgánicos. Esta matriz es modificada superficialmente con óxido de zinc (ZnO, elemento reconocido por su acción en diversos procesos biológicos y su acción antibacteriana. El procedimiento involucra la intrusión de dispersiones de ZnO en solución de alcohol-1,2,3 propanotriol, efectuadas en un baño térmico y el ulterior sinterizado a alta temperatura. El grado de fijación y la concentración del Zn sobre la matriz de hidroxiapatita se determinan por medio de microscopia electrónica y espectrometría en energías. La difracción de rayos X muestra que la incorporación de los iones de Zn en la superficie forma fosfatos de Zn. El original proceso desarrollado permite modificar, en forma sencilla, injertos óseos sintéticos, otorgando capacidad antibacteriana y osteoproliferativa al sustrato osteconductor.

  4. Application of compartmental metabolic models for determination of retention and excretion functions; Aplicacao de modelos metabolicos para a determinacao de funcoes de excrecao e retencao

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Junior, O

    1994-07-01

    After an intake of radioactive material, its behaviour in the human body can be described by mathematical models, where organs, tissues or regions of the body are treated as a chain of linked compartments. The mathematical approach for such metabolic models is usually done through a system of differential equations of first order with constant coefficients. The solutions of this system of equations associates the radionuclide intake, with the fraction excreted or retained in the organ of interest. A computer program - called INCORP and for running in PC compatible microcomputers - was developed in order to find the solutions of such system of equations, using an analytical method based on expansion of series of exponential matrices. The metabolic model presented in the ICRP-30 publication was simulated using the INCORP program, in order to find the respective retention and excretion curves for selected radionuclides. (author)

  5. Study and development of an Iridium-192 seed for use in ophthalmic cancer; Estudo e desenvolvimento de uma semente de iridio-192 para aplicacao em cancer oftalmico

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, Fabio Rodrigues de

    2013-07-01

    Even ocular tumors are not among the cases with a higher incidence, they affect the population, especially children. The Institute of Energy and Nuclear Research (IPEN-CNEN/SP) in partnership with Escola Paulista de Medicina (UNIFESP), created a project to develop and implement a alternative treatment for ophthalmic cancer that use brachytherapy iridium-192 seeds. The project arose by reason of the Escola Paulista treat many cancer cases within the Unified Health System (SUS) and the research experience of sealed radioactive sources group at IPEN. The methodology was developed from the available infrastructure and the experience of researchers. The prototype seed presents with a core (192-iridium alloy of iridium-platinum) of 3.0 mm long sealed by a capsule of titanium of 0.8 mm outside diameter, 0.05 mm wall thickness and 4,5mm long. This work aims to study and develop a seed of iridium-192 from a platinum-iridium alloy. No study on the fabrication of these seeds was found in available literature. It was created a methodology that involved: characterization of the material used in the core, creation of device for neutron activation irradiation and and seed sealing tests. As a result, proved the feasibility of the method. As a suggestion for future work, studies regarding metrology and dosimetry of these sources and improvement of the methodology should be carried out, for future implementation in national scope. (author)

  6. Evaluation of solid waste and plastic clay mixtures for structural ceramic use; Avaliacao de misturas de residuo solido com argila plastica para aplicacao em ceramica vermelha

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Neli Iloni Warpechowski da [Fundacao de Ciencia e Tecnologia (CIENTEC), Porto Alegre, RS (Brazil); Belo, Pedro [Ceramics Representacoes Comerciais Ltda, Porto Alegre, RS (Brazil)

    1996-07-01

    This work aims to verify the behaviour of the organic solid waste added by 10%, 15% and 20% in mixture in a plastic clay. It intends to emphasize the influence of the waste in the mixture. Technology tests have been carried out in the clay and mixtures to obtain possible uses in the structural ceramics. (author) 1 ref., 4 figs., 2 tabs.

  7. Development and characterization of high collapse boron alloys heat treated pipes for oil wells; Tubos de aco TiB para aplicacao em revestimento de pocos de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Fabio A.; Silva, Ronaldo; Chad, Luis [Tenaris Confab, Pindamonhangaba SP (Brazil); Fritz, Marcelo C. [Tenaris Confab, Pindamonhangaba SP (Brazil). Dept. de Engenharia do Produto

    2008-07-01

    The utilization of OCTG (Oil Country Tubular Goods) pipes will increase with the discovery of new oil wells in ultra deep waters. This study aims to evaluate the mechanical and microstructural performance of welded and heat treated pipes through quenching and tempering using a steel project based in titanium/boron for casing pipes. The objective of this development is to present a set of techniques used during the manufacturing of heated treated ERW pipes boron allowing, discussing mechanical and metallurgical aspects of the steel project, coil conformation, heat treatment and test procedures. The results are within the limits set by the API 5CT standard. It was found that the pipes obtained good geometry and uniformity of mechanical properties, showing that this product can be applied safely and reliability as wells' casing. (author)

  8. Development and application of a pediatric head phantom for dosimetry in computed tomography; Desenvolvimento e aplicacao de um simulador pediatrico craniano para dosimetria em tomografia computadorizada

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Elaine Wirney

    2016-11-01

    To determine the exposure levels and the absorbed dose in patients undergoing CT scans, is necessary to calculate the CT dose index in measurements with a PMMA or water phantom. The phantom must be enough to simulate the attenuation and scattering characteristics of a human body or parts in a radiation field. The CT specific quantities : CT air kerma index (Ca,100) , weighted CT air kerma index (CW ), a total volume CT air kerma index (Cvol) and the CT air kerma-length product (PKL) must be determined and compared to literature reference levels. In this work a head pediatric phantom was developed, considering that the Brazilian published Diagnostic Reference Levels (DRL) are based on adult phantom measurements. This developed phantom shows a construction innovation using materials to simulate the skullcap, cortical bone (aluminum) and cancellous bone (PVC), and it was filled with distilled water. The phantom dimension follows the recommendations of the World Health Organization and the International Commission on Radiation Units for children from 0 to 5 years old head size: diameter of 160 mm and height of 155 mm. The skullcap has 4 mm of thickness and 111.9 mm of internal diameter. In order to evaluate its behavior, tests were carried out in calibration laboratories and in clinical beams. The results showed attenuation up to 23% when different materials are used as skullcap, demonstrating that the DRLs adopted could be overestimating the dose received by pediatric patients. It is observed that the dose received by CT skull scans presents different distribution, due to the skullcap partially attenuation and/or backscattering which is not considered when the PMMA phantom is used.

  9. Study for application of multi fuel technology in the Brazilian automobilistic market; Estudo para aplicacao da tecnologia multi combustivel no mercado automobilistico brasileiro

    Energy Technology Data Exchange (ETDEWEB)

    Gasparotto, Alexsander David [FIAT/GM Powertrain (Brazil); Massarani, Marcelo [Universidade de Sao Paulo (USP), SP (Brazil)

    2006-07-01

    The objective of this work is a study for the application of a new technology that will be used in the engine management system in the vehicle; where the final consumer can opt for the inquiry performance or seeking an economy for the fuel consumption depending on its daily use and of the prices offered in the gas stations. Flexible Fuel is a technology in development for the automobile market that mixes the use of two fuels (gasoline and ethanol) and their mixtures in the internal combustion engine. (author)

  10. Application of finance project for leverage of small size hydroelectric enterprising; Aplicacao do project finance para alavancagem de empreendimentos hidreletricos de pequeno porte

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Silvana dos

    2003-07-01

    In the same way that the majority of the countries, project financing of substructure in Brazil, in project finance modality, depend on a skillful structure of guaranties and contracts to become possible. In the case of projects of centrals of generation of electrical energy, that financial engineering becomes still more complicated. In Brazil, due to particularities of the sectors of electricity, the arrangements of guaranties requested but creditors pass to present levels of complexity and exigency well elevated. The contractual appliances that give support to the project finance, originally projected to developed countries, request an extreme adaptation to these particularities. The development of Brazil is directly related to its capacity in expanding the offer of electric energy in the just measure of the national necessity. In this context, the small central hydroelectric (PCH's) represent, actually, an efficient and fast form to complete the offer of energy in such a way to supply the crescent demand the national market. For its characteristics, that type of undertaking can be developed by small manager, from among which are the owners of the areas in which on can find these hydraulic potentials which, however they do not dispose of capital to integral raising. These undertakings are tasks, normally, of low global cost, at the rate of US$ 1.000,00/k W, and of a smaller ambient impact, compared to the return that they give to the enterprise and to the Brazilian electric system as a whole, by having to receive special attention in the planned politics to the sector and to merit a series of incentives to become business still more attractive. By thinking in the found difficulty by small enterprises in rising undertakings of generation of electric energy of small port through the convectional mechanisms of financing is being proposed in that work a well-founded methodology in the concepts of the modality of financing project finance. (author)

  11. Production of LiF films for dosimetric thermoluminescence application; Producao de filmes de LiF para aplicacao em dosimetria termoluminescente

    Energy Technology Data Exchange (ETDEWEB)

    Mauricio, Claudia Lucia de Pinho

    2000-12-01

    This work studies the LiF monolayer and multilayer polycrystalline film's dosimetric properties. The films were produced by electron beam evaporation technique in aluminium and stainless steel substrates maintained at several temperatures. As dosimetric variable, the intensity of the thermoluminescent (TL) glow curve of the films was used. effects of the substrate type and temperature; of the addition of layers of Mg F{sub 2} NaF and Cu F{sub 2} to the LiF films; and of thermal treatments in the TL response of the produced films were studied. The microstructural characterization of the films was accomplished through measures of scanning electronic microscopy and grazing incidence X-rays diffraction analysis. The dosimetric characterization was made of gamma radiation exposure in a {sup 60} Co source, with kerma from 0,1 to 500 Gy. Studies of reproducibility, homogeneity, stability and other environmental effects were also made. LiF and Cu F{sub 2}: LiF; Mg F{sub 2} films were the only ones that presented mechanical stability and reproducibility of the TL emission. There is a strong indication of some correlation between the residual tension fields inside the films and the intensity of its TL emission peaks. LiF monolayer films present supralinear behaviour from 0,2 to 100 Gy. These films present a main TL glow peak around 150 deg C, whose half-time is about 30 days. Its volumetric sensitivity can reach about 60 times that of LiF powder and about 0,25 that of TLD100 (LiF:Mg, Ti commercial dosimeter from Harshaw Chemical Co.) The homogeneity and reproducibility inside a same film batch is better than 12% for 95% confidence level. Cu F{sub 2} : LiF: Mg F{sub 2} films present linear behaviour from 3 to 500 Gy and its main TL glow peak around 200 deg C did not present any fading for a a period of 30 days, in laboratory conditions. This glow peak is characteristic of the Mg doping of LiF, which confirms the diffusion of Mg ions from the Mg F{sub 2} layer to the LiF layer. The TL volumetric sensitivity of these films is about four times that of LiF powder and about 1% that of TLD 100. The homogeneity and reproducibility inside a same film batch is better than 20% for 95% of confidence level. (author)

  12. New technologies application to increase the transmission capacity in power systems; Aplicacao de novas tecnologias para aumentar a capacidade de transmissao em sistemas de potencia

    Energy Technology Data Exchange (ETDEWEB)

    Figueiredo, Erli Ferreira [Universidade do Estado, Rio de Janeiro, RJ (Brazil)]. E-mail: erli@openlink.com.br

    2001-07-01

    The deregulation and the Brazilian electric sector new formulation associated to the growth of the electric energy market, has been contributing to increase the power flows through located transmission lines in one same region, as well as in different regions. This increase of flow will require the construction of new transmission lines, in general associated to eventual efforts in the system. However, due to environmental restrictions and to difficulties for acquisition of free soil bands for transmission lines, in this article new technologies of transmission in order to increase the capacity of the existing and future power systems are presented, with the purpose of preventing or postponing the construction of new transmission lines.

  13. Development of aptamers for use as radiopharmaceuticals in the bacterial infection identification; Desenvolvimento de aptameros especificos para aplicacao como radiofarmacos na identificacao de bacterias

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Ieda Mendes

    2013-08-01

    The difficulty in early detection of specific foci caused by bacteria in the bacterial infection has raised the need to search for new techniques for this purpose, since these foci require prolonged treatment with antibiotics and in some cases even drainage or, if applicable, removal of prostheses or grafts. Detection of bacterial infections by scintigraphy had the advantage that a whole body image could be obtained, since specific tracers were available. This study aims to obtain aptamers specific for bacteria identification for future use as radiopharmaceutical. The SELEX (Systematic Evolution of Ligands by Exponential Enrichment) methodology can generate oligonucleotides (aptamers) that are able to bind with high affinity and specificity to a specific target, from small molecules to complex proteins, by using rounds of enrichment and amplification. Aptamers can be labeled with different radionucleotides such as {sup 99}mTc, {sup 18}F and {sup 32}P. In this study, aptamers anti-peptidoglycan, the main component of the bacterial outer cell wall, were obtained through SELEX. Whole cells of Staphylococcus aureus were also used to perform the SELEX to cells (cell-SELEX). The selection of aptamers was performed by two different procedures (A and B). The A process has been accomplished by 15 SELEX rounds in which the separation of the oligonucleotides bound to the peptidoglycan of unbound ones was performed by filtration. In the B process 15 SELEX rounds were performed using the centrifugation for this separation, followed by 5 rounds cell-SELEX. The SELEX started with a pool of ssDNA (single stranded DNA). For A process, initially a library of ssDNA was incubated with peptidoglycan and the amplification of oligonucleotides that were able to bind to peptidoglycan was performed by PCR (Polymerase Chain Reation). The amplified oligonucleotides were again incubated with peptidoglycan, amplified and purified. At the end of 15 selection rounds the selected oligonucleotides were cloned. The product of recombination was used to transform Escherichia coli ToplOF'. The plasmid DNA from 40 selected colonies were extracted and quantified. The plasmids were sequenced, two different sequences (Antibac1 and Antibac2) were obtained and their secondary structures determined. The aptamers obtained were synthesized and labeled with {sup 32}p. The labeled aptamers were incubated with S. aureus cells and the amount of radiolabeled ssDNA was determined by liquid scintillation spectrometry. The oligonucleotides library labeled with {sup 32}p was used as control. For the aptamer Antibac1 the radiation linked to the pellet was 28 times higher than obtained with the control and for the Antibac2 was 22 higher. A specific assay was conducted with labeled aptamers using S. aureus, E. co ti, Candida albicans and human fibroblasts. For both aptamers (Antibac1 and Antibac2) binding to bacterial cells was significantly higher than for C. albicans and fibroblasts, demonstrating their specificity for bacteria. For B process, after 15 SELEX rounds was performed the cell-SELEX starting with the products 15th round being incubated with S. aureus cells. The amplified oligonucleotides were incubated again with the bacteria in the next round and so on. At the end of the 5 rounds of selection, the selected oligonucleotides were cloned and sequenced as in A process. Eleven different sequences from 21 clones were obtained and their secondary structures were determined. The aptamers obtained by process A showed high affinity and specificity for bacteria. The aptamers obtained by process B will be evaluated for these parameters in a future work. (author)

  14. Hybrid membranes PVA/silicon for use in fuel cells; Membranas hibridas de PVA/silica para aplicacao em celula a combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Liz C.V. de; Almeida, Raquel D. de; Gomes, Ailton de S. [Universidade Federal do Rio de Janeiro - UFRJ, Instituto de Macromoleculas Professora Eloisa Mano - IMA, RJ (Brazil)], e-mail: lizcontino@ima.ufrj.br; Ramos Filho, Florencio G. de [Centro Universitario Estadual da Zona Oeste - UEZO, Rio de Janeiro, RJ (Brazil)

    2011-07-01

    Hybrids organic-inorganic membranes PVA-silica have been prepared using sol-gel process in situ with the objective of study the influence of inorganic particles incorporation on the water uptake, pervaporation and proton conductivity of PVA membranes. The silica was constituted of mercaptopropyltrimethoxysilane (MPTMS) with or without the mixture with the tetra ethoxysilane (TEOS). The hybrids membranes were oxidated to convert the -SH groups in -SO{sub 3}H groups, becoming them proton conducting. The hybrids membranes not oxidated showed lesser water uptake and pervaporated material, probably, due to the formation of crosslink that restricted the swell of the PVA membrane. The protonic conductivity of the hybrid membranes after the oxidation was up to 26 times bigger than of the membrane not oxidated. (author)

  15. Application of the FDK algorithm for multi-slice tomographic image reconstruction; Aplicacao do algoritmo FDK para a reconstrucao de imagens tomograficas multicortes

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Paulo Roberto, E-mail: pcosta@if.usp.b [Universidade de Sao Paulo (IFUSP), SP (Brazil). Inst. de Fisica. Dept. de Fisica Nuclear; Araujo, Ericky Caldas de Almeida [Fine Image Technology, Sao Paulo, SP (Brazil)

    2010-08-15

    This work consisted on the study and application of the FDK (Feldkamp- Davis-Kress) algorithm for tomographic image reconstruction using cone-beam geometry, resulting on the implementation of an adapted multi-slice computed tomography system. For the acquisition of the projections, a rotating platform coupled to a goniometer, an X-ray equipment and a digital image detector charge-coupled device type were used. The FDK algorithm was implemented on a computer with a Pentium{sup R} XEON{sup TM} 3.0 processor, which was used for the reconstruction process. Initially, the original FDK algorithm was applied considering only the ideal physical conditions in the measurement process. Then some artifacts corrections related to the projections measurement process were incorporated. The implemented MSCT system was calibrated. A specially designed and manufactured object with a known linear attenuation coefficient distribution ({mu}(r)) was used for this purpose. Finally, the implemented MSCT system was used for multi-slice tomographic reconstruction of an inhomogeneous object, whose distribution {mu}(r) was unknown. Some aspects of the reconstructed images were analyzed to assess the robustness and reproducibility of the system. During the system calibration, a linear relationship between CT number and linear attenuation coefficients of materials was verified, which validate the application of the implemented multi-slice tomographic system for the characterization of linear attenuation coefficients of distinct several objects. (author)

  16. EPR response characterization of drugs excipients for applying in accident dosimetry; Caracterizacao da resposta RPE dos excipientes dos medicamentos para aplicacao em dosimetria de acidente

    Energy Technology Data Exchange (ETDEWEB)

    Marczewski, Barbara S.; Rodrigues Junior, Orlando; Galante, Ocimar L.; Costa, Zelia M. da; Campos, Leticia L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    2002-07-01

    Some drugs are widely used by the population and can be employed to dose retrospective. The carbohydrates (saccharides), commonly used as excipients in the pharmaceutical industry, produce a quantity of free radicals after gamma irradiation, making them useful for dosimetry in emergency or accident situations that imply in dose evaluation from the materials found nearly or in contact with victims. In general, EPR signal from pulverized pills of some drugs are very complex due to the variety of components in the formulation. Because of this fact, some pharmaceutical excipients identified in the pill composition were also analysed by EPR spectrometry. On the counter drugs were studied: Cebion glucose, AAS, Aspirina, Conmel, Lacto-Purga and sugar substitutive ZeroCal. The excipients were: lactose, amide, anhydrous glucose and magnesium stearate. In some samples the number of radicals produced increased with the dose, showing a linear response for a dose range of interest and an adequate sensibility for dosimetry in accident cases.

  17. Application of oil spill environmental vulnerability analysis to Brazilian road networks for hazardous cargo transportation; Aplicacao do indice de vulnerabilidade rodoviario para transporte de cargas perigosas

    Energy Technology Data Exchange (ETDEWEB)

    Mattos, M. Beatriz da Costa; Silva Junior, Carlos Leandro da; Almeida, Ana Flavia Oliveira de [Ambipetro Consultoria em Meio Ambiente e Petroleo Ltda., Natal, RN (Brazil)

    2008-07-01

    Roads provide the main means of transportation in Brazil. According to data from the Brazilian Department of Infrastructure and Transport, 96.2% of the passenger transportation and 61.8% of the cargo transportation are based on road infrastructure. However, three quarters of the Brazilian roads are in terrible, unsatisfactory or generally inadequate condition. Poor road conditions are responsible for a great number of accidents with severe consequences for the population and the environment. Given the importance of this matter, there is a need to develop an intelligent system for automatic classification of social and environmental sensitivity maps in order to support actions that respond to emergencies and to help in transportation planning, especially considering the heavy movement of hazardous cargoes such as petroleum and its derivates. For this, tools such as Geographic Information System (GIS) allow social-environmental and traffic engineering characterization maps to be analyzed on a unified, geo referenced digital base. This way, administrators can estimate which stretches of the network are more environmentally sensitive and which pose greater risks, and therefore draw inferences on the most socially and environmentally vulnerable. Social and environmental vulnerability data not only help in the classification of the areas which pose the greater risks, but also make it possible to decide on emergency support points, creating a culture of prevention in the area of hazardous cargo transportation. The case study on the state of Rio Grande do Norte provides a measure of the importance of such work. The city of Natal - the state capital - and the Guamare petrochemical facility are interconnected by 180 Km Road, on which more than 100 tanker trucks loaded with diesel and its derivates travel every day. This road is classified as in poor conditions and, according to the Brazilian Roads Police, it is one of the most dangerous. The relevance of this work is to show how information consolidated to a single database, geo referenced in a GIS, can assist planning for the safe transport of oil and hazardous cargoes, benefiting not only the state's population but the environment as a whole. (author)

  18. Analysis of ferritic stainless steel tube applied in radiation furnaces; Analise de tubos de aco inoxidavel ferritico para aplicacao em fornos de radiacao

    Energy Technology Data Exchange (ETDEWEB)

    Porto, P.C.R.; Spim, J.A. [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Centro de Tecnologia. Lab. de Fundicao], e-mail: spim@ufrgs.br; Santos, C.A. [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Fac. de Engenharia. Programa de Pos-Graduacao em Engenharia e Tecnologia de Materiais (PGETEMA)

    2006-07-01

    The objective of this work was to evaluate the change in mechanic properties and phase transformations of ferritic stainless steel tube, ASTM 268 Gr 446, applied in high temperature conditions. The work has used tubes from radiation furnaces of the PETROBRAS Xisto Industrialization Unit. The samples used for comparison were obtained from new tubes and tubes already used in furnaces. The test analyses were optical metallography, scanning electron microscopy, energy dispersive spectrometer, hardness and microhardness test and tension test. Results have shown that the new tubes presented a ferritic matrix and in old tubes were observed a great quantity of sigma phase and carbides. Along with the thickness of the tubes it was verified that the inside region presented an increase of sulfate and the outside region an increase of carbides. (author)

  19. Synthesis of calcium aluminate with silicon addition for application in biomaterials; Sintese de aluminato de calcio com adicao de prata para aplicacao em biomateriais

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, P.J.; Almeida, L.H.S.; Pappen, F.G.; Ribeiro, A.S.; Cava, S.S. [Universidade Federal de Pelotas (UFPel), RS (Brazil); Veiga, F.C.T.; Jurado, J., E-mail: ati_jg@hotmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil)

    2016-07-01

    Ceramic materials have biocompatibility have been studied, researched and applied in various treatments such as endodontics and orthopedics. This study aims to carry out the synthesis by the polymeric precursor method for post calcium trialuminato (C3A) and with addition of 1% and 5% silver, them the powders were calcined in de temperature 1000°C, carried out a comparative study between them. The ceramic powders were characterized by X-ray diffraction, having a phase composition, scanning electron microscopy (SEM) associated with EDS observed grain morphology and quantity of the chemical elements. The analysis flow, pH, release of calcium ions (Ca{sup 2+}) and silver ions (Ag{sup +}) were evaluated with the sealer MTA Fillapex result that calcium aluminate addition of silver improved the MTA Fillapex stream with the release of ions Ca{sup +2}, being a material that allows applications in the field of endodontics. (author)

  20. Treatment of chemical waste piassava for application in polymeric composites; Tratamento quimico do residuo de piacava para aplicacao em compositos polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, C.S.; Fiuza, R.P.; Guimaraes, D.H.; Carvalho, G.G.P.; Carvalho, R.F.; Jose, N.M., E-mail: cleidienesm@gmail.co [Universidade Federal da Bahia (GECIM/UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Energia e Ciencias dos Materiais

    2010-07-01

    Piassava fibers were investigated with the aim of adding new business value. The surface of the fibers were treated with NaOH and H{sub 2}SO{sub 4} for 1 h at room temperature. The samples were characterized by FTIR, TGA, DSC, chemical composition, XRD, SEM and tensile tests. The micrographs of the fibers showed that treatment with NaOH cleaned the fiber surface of a large amount of impurities and cause fibrillation. Chemical analysis, using the Van Soest method, showed that the palm fiber is a fiber rich in lignin, as evidenced by their brown color and with alkali treatment there was partial removal of hemicellulose and lignin, increasing the crystallinity index of the fiber, observed by XRD. The acid treatment caused no significant changes in the properties of the fiber. Therefore, the mercerisation was efficient in the fiber of palm fiber, improving their properties, enabling thus their use as reinforcement in polymer composites. (author)

  1. Polyester synthesis for application in PEMFC type fuel cells; Sintese de poliester para aplicacao em celulas a combustivel do tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, R.P.; Souza, D.R. de; Fiuza, R.A.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica], e-mail: raigenis@gmail.com

    2006-07-01

    The PEMFC (Proton Exchange Membrane Fuel Cell), along the SOFC (Solid Oxide Fuel Cell), is the most important technology, among the various types of fuels cell. The PEMFC shows a large versatility of applications, both for stationary and mobile use. However the PEMFC presents high manufacture cost, directly impacting in the cost of the produced energy. This work contemplates the previews sulfonation of phtalic acid and its subsequent polymerization with glycerol, using as catalytic tin dibutyl-dilaurate. The obtained material has been characterized by DSC, TGA, FTIR, MEV, DRX and XRF. The gotten results indicated that phtalic acid was sulfonated and the increase of the sulfonation degree significantly increased the crystallinity of the sulfonated ftalico acid. Furthermore, the polymer produced from the sulfonated monomer presented adequate thermal resistance and a high content of conducting groups, necessary conditions for application as electrolyte in PEMFC. All these characteristics, particularly the low cost of the reagents and the ease of production process, make the sulfonated polyester membrane a promising candidate as fuel cell electrolyte. (author)

  2. Study for application of flexible fuel technology in the Brazilian automobile market; Estudo para aplicacao da tecnologia multi combustivel no mercado automobilistico brasileiro

    Energy Technology Data Exchange (ETDEWEB)

    Gasparotto, Alexsander David [FIAT/GM Powertrain (Brazil); Massarani, Marcelo [Sao Paulo Univ., SP (Brazil). Escola Politecnica

    2006-07-01

    The objective of this work is a study for the application of a new technology that will be used in the engine management system in the vehicle; where the final consumer can opt for the inquiry performance or seeking an economy for the fuel consumption depending on its daily use and of the prices offered in the gas stations. Flexible Fuel is a technology in development for the auto mobile market that mixes the use of two fuels (gasoline and ethanol) and their mixtures in the internal combustion engine. (author)

  3. Application of finance project for leverage of small size hydroelectric enterprising; Aplicacao do project finance para alavancagem de empreendimentos hidreletricos de pequeno porte

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Silvana dos

    2003-07-01

    In the same way that the majority of the countries, project financing of substructure in Brazil, in project finance modality, depend on a skillful structure of guaranties and contracts to become possible. In the case of projects of centrals of generation of electrical energy, that financial engineering becomes still more complicated. In Brazil, due to particularities of the sectors of electricity, the arrangements of guaranties requested but creditors pass to present levels of complexity and exigency well elevated. The contractual appliances that give support to the project finance, originally projected to developed countries, request an extreme adaptation to these particularities. The development of Brazil is directly related to its capacity in expanding the offer of electric energy in the just measure of the national necessity. In this context, the small central hydroelectric (PCH's) represent, actually, an efficient and fast form to complete the offer of energy in such a way to supply the crescent demand the national market. For its characteristics, that type of undertaking can be developed by small manager, from among which are the owners of the areas in which on can find these hydraulic potentials which, however they do not dispose of capital to integral raising. These undertakings are tasks, normally, of low global cost, at the rate of US$ 1.000,00/k W, and of a smaller ambient impact, compared to the return that they give to the enterprise and to the Brazilian electric system as a whole, by having to receive special attention in the planned politics to the sector and to merit a series of incentives to become business still more attractive. By thinking in the found difficulty by small enterprises in rising undertakings of generation of electric energy of small port through the convectional mechanisms of financing is being proposed in that work a well-founded methodology in the concepts of the modality of financing project finance. (author)

  4. Conductor polymeric membranes with potential for application in PEM type fuel cells; Membranas polimericas condutoras com potencialidades para aplicacao em celulas a combustivel do tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Brioude, Michel de Meireles; Sodre, Livia Farias; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil)

    2006-07-01

    In this work two series of membranes were prepared; they were based on hybrid organic-inorganic or composite materials and presented potentiality for application in Proton Exchange Membrane Fuel Cell, PEMFC. The polymeric phase was constituted of poly(dimethylsiloxane), PDMS, crosslinked with tetra ethoxysilane, TEOS, with a 70%/30% ratio. Phosphotungstic acid (PWA) or the sodium monododecylsulphate (MDS), as proton conductors, were added to the inorganic network, close to the gel point; the mixtures were transferred to a cast. The films were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The membranes showed good properties, as flexibility, thermal and mechanical stability with potentiality to be used as conducting membranes in technological applications. (author)

  5. Development of crystals based in cesium iodide for application as radiation detectors; Desenvolvimento de cristais baseados em iodeto de cesio para aplicacao como detectores de radiacao

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Maria da Conceicao Costa

    2006-07-01

    Inorganic scintillators with fast luminescence decay time, high density and high light output have been the object of studies for application in nuclear physics, high energy physics, nuclear tomography and other fields of science and engineering. Scintillation crystals based on cesium iodide (CsI) are matters with relatively low higroscopy, high atomic number, easy handling and low cost, characteristics that favor their use as radiation detectors. In this work, the growth of pure CsI crystals, CsI:Br and CsI:Pb, using the Bridgman technique, is described. The concentration of the bromine doping element (Br) was studied in the range of 1,5x10{sup -1} M to 10{sup -2} M and the lead (Pb) in the range of 10{sup -2} M to 5x10{sup -4} M. To evaluate the scintillators developed, systematic measurements were carried out for luminescence emission and luminescence decay time for gamma radiation, optical transmittance assays, Vickers micro-hardness assays, determination of the doping elements distribution along the grown crystals and analysis of crystals response to the gamma radiation in the energy range of 350 keV to 1330 keV and alpha particles from a {sup 241}Am source, with energy of 5.54 MeV. It was obtained 13 ns to 19 ns for luminescence decay time for CsI:Br and CsI:Pb crystals. These results were very promising. The results obtained for micro-hardness showed a significant increase in function of the doping elements concentration, when compared to the pure CsI crystal, increasing consequently the mechanical resistance of the grown crystals. The validity of using these crystals as radiation sensors may be seen from the results of their response to gamma radiation and alpha particles. (author)

  6. Gold nanoparticles applications in natural polymer modified for UV protection; Aplicacao de nanoparticulas de ouro em polimero natural modificado para protecao ultravioleta

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Iris O. da; Ladchumananandasivam, Rasiah; Nascimento, Jose H. O. do; Silva, Francisco C. da; Sa, Christiane S. de A., E-mail: iris.oliveira@gmail.com.br [Universidade Federal do Rio Grande do Norte (PPGEM/UFRN), Natal, RN (Brazil)

    2015-07-01

    The protein-based polymers such as milk, such as polylactic acid (PLA) and soya can be cited as examples of substrates used in various fields of engineering, mainly due to its character of biodegradability, generating low environmental impact when compared to chemical polymers to petroleum-based, which take years to decompose in nature. Among these, soy fiber has great application potential because it is a manufactured material base of a residue obtained from the existing folder in the soybean seeds after oil extraction, using resins and chemicals for structural modification. In this work, soy mesh was used to develop a material with ultraviolet protection properties, through the use of nanotechnology. Thus, to connect the gold nanoparticles (NPAu), the fabric had a surface charge modified with the use of chitosan, using 20% of the weight of the material, followed by nanomaterials exhaust process. The NPAu were synthesized via chemical synthesis with sodium nitrate as reducing and stabilizing agent. The analysis of the solution samples were evaluated by absorbance spectroscopy and solid materials through diffuse reflectance spectroscopy and XRD X-ray diffraction. The size of NPAu was evaluated in equipment Zetasizer nanoseries / nanoZ, finding nanoparticles with an average size of 34.59 nm, and also underlined plasmon resonance phenomenon, with peaks between 530 nm and red coloration, and good results from the soundness washes, compared to conventional dyeing. It was found that soy polymer treated with NPAu presented an excellent property with ultraviolet protection factor (UPF) of +50, considered excellent, proving its potential application in the biomedical field. (author)

  7. Development of Ti-12Mo-3Nb alloy for biomedical application; Desenvolvimento da liga Ti-12Mo-3Nb para aplicacao biomedica

    Energy Technology Data Exchange (ETDEWEB)

    Panaino, J.V.P.; Gabriel, S.B., E-mail: josevicentepanaino@hotmail.co [Centro Universidade de Volta Redonda (UNIFOA), RJ (Brazil); Mei, P. [Universidade Estadual de Campinas (DEMa/UNICAMP), SP (Brazil). Dept. de Materiais; Brum, M.V. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Programa de Engenharia Metalurgica e de Materiais; Nunes, C.A. [Universidade de Sao Paulo (EEL/USP), Lorena, SP (Brazil). Escola de Engenharia

    2010-07-01

    The titanium alloys are quite satisfactory for biomedical applications due to their physical, mechanical and biological properties. Recent studies focuses on the development of beta type titanium alloys, composed of toxic elements (Nb, Mo, Ta ,...), because they have more advantages than alpha and alpha + beta (Ti- 6Al-4V) alloys such as lower modulus of elasticity, better plasticity and, moreover, the process variables can be controlled to produce selected results. This project focused on the development and characterization of Ti-12Mo-3Nb alloy in the condition 'as cast' and after thermomechanical treatment. The material was characterized in different conditions by X-ray diffraction, optical microscopy, microhardness measurements and elasticity modulus. The results showed that the forged Ti-12Mo-3Nb alloy showed the best combination of properties, being a promising candidate for use as implant. (author)

  8. Mechanodynamical analysis of nickel-titanium alloys for orthodontics application; Analise mecanodinamica de ligas de niquel-titanio para aplicacao ortodontica

    Energy Technology Data Exchange (ETDEWEB)

    Arruda, Carlos do Canto

    2002-07-01

    Nickel-titanium alloys may coexist in more than one crystalline structure. There is a high temperature phase, austenite, and a low temperature phase, martensite. The metallurgical basis for the superelasticity and the shape memory effect relies in the ability of these alloys to transform easily from one phase to another. There are three essential factors for the orthodontist to understand nickel-titanium alloys behaviour: stress; deflection; and temperature. These three factors are related to each other by the stress-deflection, stress-temperature and deflection-temperature diagrams. This work was undertaken with the objective to analyse commercial nickel-titanium alloys for orthodontics application, using the dynamical mechanical analyser - DMA. Four NiTi 0,017 X 0,025'' archwires were studied. The archwires were Copper NiTi 35 deg C (Ormco), Neo Sentalloy F200 (GAC), Nitinol Superelastic (Unitek) and NiTi (GAC). The different mechanodynamical properties such as elasticity and damping moduli were evaluated. Each commercial material was evaluated with and without a 1 N static force, aiming to evaluate phase transition temperature variation with stress. The austenitic to martensitic phase ratio, for the experiments without static force, was in the range of 1.59 to 1.85. For the 1 N static force tests the austenitic to martensitic phase ratio, ranged from 1.28 to 1.57 due to the higher martensite elasticity modulus. With elastic modulus variation with temperature behaviour, the orthodontist has the knowledge of the force variation applied in the tooth in relation to the oral cavity temperature change, for nickel-titanium alloys that undergo phase transformation. The damping capacity of the studied alloys depends on the materials state: martensitic phase; austenitic phase or during phase transformation. The martensitic phase shows higher dumping capacity. During phase transformation, an internal friction peak may be observed for the CuNiTi 35 deg C and Neo Sentalloy F200 alloys. The austenitic phase shows a low damping capacity. According to the evaluation of the damping capacity against temperature, it was possible to better understand the phase transformation behaviour of these alloys. The differential scanning calorimetry was used in order to evaluate the phase transformation process, giving the initial and ending temperatures of the austenitic transformation and the initial and ending temperatures of the martensitic transformation of the studied alloys. (author)

  9. Method for evaluating the applicability and application rate wastes in soil; Metodo para avaliacao da aplicabilidade e taxa de aplicacao de residuos em solo

    Energy Technology Data Exchange (ETDEWEB)

    Linhares, Monica Moreira [Partime (Brazil); Seabra, Paulo Negrais [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    1991-01-01

    Land treatment of refinery solid wastes has been practiced in the last few years by some PETROBRAS refineries. The biodegradation process is dynamic and complex, and incorrect monitoring may destroy the potential of the soil. Due to great differences both in terms of soils and of residues, each case must be monitored individually. We therefore developed a monitoring method for land farming systems based on the impact of the waste on indigenous soil microbial populations. The method is extremely simple, requiring only a gas chromatograph to evaluate the CO{sub 2} evolution, and can detect possible causes for low efficiency biodegradation processes. Conditions should then be altered, to ensure adequate functioning of the system.The method also allows for determination of the applicability of candidate wastes and of acceptable waste application rates in soil. (author) 2 refs., 7 figs.

  10. Modification of a cellulose derived for your application on enzyme immobilization;Modificacao de um derivado celulosico para sua aplicacao na imobilizacao de enzimas

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Elaine S.; Rodriguez, Ruben J.S.; Lamonica, Alano C., E-mail: ecarvalho@uenf.b [Universidade Estadual do Norte Fluminense Darcy Ribeiro (LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil). Lab. de Materiais Avancados; Tavares, Maria Ines B. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Profa. Eloisa Mano

    2009-07-01

    The chemical modification of (acrylamidomethyl) cellulose acetate propionate (AMCAP) was done through the technique of grafting via radical using acrylic acid as modifier, with the objective to make the polymer more hydrophilic. The structural characterization of AMCAP and modified AMCAP-H{sub 2}O{sub 2} was analysed by using the technique of {sup 13}C-nuclear magnetic resonance (NMR-{sup 13}C). By the techniques differential scanning calorimetry analysis (DSC) and thermogravimetric analysis (TGA), the thermal properties was characterized and the hydrophobic / hydrophilic character was determined by measurements of the contact angle. The results show that occurred the change intended with the introduction of acrylic acid in the side chain of the polymer, increasing the hydrophilic character on the AMCAP. (author)

  11. Mechanodynamical analysis of nickel-titanium alloys for orthodontics application; Analise mecanodinamica de ligas de niquel-titanio para aplicacao ortodontica

    Energy Technology Data Exchange (ETDEWEB)

    Arruda, Carlos do Canto

    2002-07-01

    Nickel-titanium alloys may coexist in more than one crystalline structure. There is a high temperature phase, austenite, and a low temperature phase, martensite. The metallurgical basis for the superelasticity and the shape memory effect relies in the ability of these alloys to transform easily from one phase to another. There are three essential factors for the orthodontist to understand nickel-titanium alloys behaviour: stress; deflection; and temperature. These three factors are related to each other by the stress-deflection, stress-temperature and deflection-temperature diagrams. This work was undertaken with the objective to analyse commercial nickel-titanium alloys for orthodontics application, using the dynamical mechanical analyser - DMA. Four NiTi 0,017 X 0,025'' archwires were studied. The archwires were Copper NiTi 35 deg C (Ormco), Neo Sentalloy F200 (GAC), Nitinol Superelastic (Unitek) and NiTi (GAC). The different mechanodynamical properties such as elasticity and damping moduli were evaluated. Each commercial material was evaluated with and without a 1 N static force, aiming to evaluate phase transition temperature variation with stress. The austenitic to martensitic phase ratio, for the experiments without static force, was in the range of 1.59 to 1.85. For the 1 N static force tests the austenitic to martensitic phase ratio, ranged from 1.28 to 1.57 due to the higher martensite elasticity modulus. With elastic modulus variation with temperature behaviour, the orthodontist has the knowledge of the force variation applied in the tooth in relation to the oral cavity temperature change, for nickel-titanium alloys that undergo phase transformation. The damping capacity of the studied alloys depends on the materials state: martensitic phase; austenitic phase or during phase transformation. The martensitic phase shows higher dumping capacity. During phase transformation, an internal friction peak may be observed for the CuNiTi 35 deg C and Neo Sentalloy F200 alloys. The austenitic phase shows a low damping capacity. According to the evaluation of the damping capacity against temperature, it was possible to better understand the phase transformation behaviour of these alloys. The differential scanning calorimetry was used in order to evaluate the phase transformation process, giving the initial and ending temperatures of the austenitic transformation and the initial and ending temperatures of the martensitic transformation of the studied alloys. (author)

  12. Cooperative research and the carbon fiber development for application in uranium centrifuges project; Pesquisa cooperativa e o desenvolvimento de fibra de carbono para aplicacao em ultracentrifugas nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Paulo Cesar Beltrao [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sao Paulo, SP (Brazil)], e-mail: paulocbqueiroz@gmail.com; Zouain, Desiree Moraes [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: dmzouain@ipen.br

    2009-08-15

    This paper analyzes both the carbon fiber-based development for uranium centrifuges and the research project that supports its development effort over time. The carbon fibre-based engineering properties make it a valuable supply for high technological products, such as uranium ultracentrifuge. There is no production of such fibers in Brazil. Its trade is subject to international market restrictions due to carbon fibers' dual applications. The Centro Tecnologico da Marinha em Sao Paulo (CTMSP), the Universidade de Campinas (UNICAMP), the Universidade de Sao Paulo (USP), the RADICIFIBRAS Company, and the Financiadora de Estudos e Projetos (FINEP), which is responsible for the project financial support, established a partnership aiming the development of a domestic polyacrylonitrile (Pan)-based carbon fiber industry. Such alliances or technological partnerships are best known in developed countries, such as USA and Japan, as Cooperative Research or Research Joint Ventures (RJV). (author)

  13. Application of activation analysis for determination of some elements in cassiterite samples; Aplicacao da analise por ativacao para a determinacao de alguns elementos em amostras de cassiterita

    Energy Technology Data Exchange (ETDEWEB)

    Armelin, Maria Jose Aguirre

    1978-07-01

    This work consists in the development of an analytical method using activation by thermal neutrons for the determination of some minor elements and traces present in cassiterite (tin ore). This method was then applied to determine these elements in samples of cassiterite from different regions of Brazil. An analysis was made of the mineralogy characteristic of cassiterite as well as of the minerals most commonly associated with it. Four main types of interference were found to occur in the analysis by activation of trace elements in samples of cassiterite. The method involves the analysis without chemical separation for the determination of some elements and the analysis with chemical separation for the determination of other elements. The steps involved in both types of analysis are described. In the analysis with chemical separation the matrix element (tin) is separated by distillation in an H{sub 2}SO{sub 4}-HBr medium, after fusion of the ore with Na{sub 2}O{sub 2}. Arsine and antimony are determined in the distilled, whereas some lanthanide elements and uranium are determined in the distillation residue by separating them as a group by precipitation with lanthanum fluoride. A discussion on the precision, accuracy and sensibility of the method is also included. (author)

  14. Commutated inversor at low frequency for application of fuel cells in distributed generation; Inversor comutado em baixa frequencia para aplicacao de CaCs na geracao distribuida

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Geomar Machado; Pomilio, Jose Antenor; Vendrusculo, Edson A. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Eletrica e de Computacao], e-mail: antenor@dsce.fee.unicamp.br

    2004-07-01

    The connection of Fuel Cell Power Plants with the utility grid generally needs an electronic power converter for processing the locally generated power and injecting current into the system. Since the source provides a DC voltage, the converter must be able to produce a low-distortion, high-power factor AC current. This paper presents the results obtained with use of a three-phase and a single-phase inverter using low-frequency commutation. An auxiliary circuit is added to the inverter topologies in order to reduce the output voltage distortion, thus improving the current waveform. The main advantages of this approach are the minimization of the switching losses (i.e. high efficiency) and the elimination of the EMI (which avoids high-frequency filters necessary in high-frequency commutation inverters). (author)

  15. Application of phase diagrams to obtain a new surfactant-based fracturing gel; Aplicacao de diagrama de fases para obtencao de um novo gel de fraturamento hidraulico

    Energy Technology Data Exchange (ETDEWEB)

    Dantas, Tereza N. de Castro; Santana, Vanessa C.; Dantas Neto, Afonso A.; Franca Neta, Luzia S. de; Albuquerque, Heraldo S. [Rio Grande do Norte Univ., Natal, RN (Brazil)]. E-mail: tereza@eq.ufrn.br

    2003-07-01

    Through pseudo ternary phases diagram was defined a gel area with the objective of obtaining a new surfactant-based fracturing gel. The surfactant used was synthesized from regional vegetable oil. Fracturing gel properties, like: viscosity, leak off coefficient and proppant-settling rate were analyzed. The obtained results with the surfactant-based gel had its properties compared with a HPG-based gel (hydroxypropyl guar). Rheological tests was accomplished at 100 s{sup -1} being varied the temperature from 26 to 86 deg C, where the surfactant-based gel showed great results. The leak off coefficient was determined by static filtration and the new gel presented smaller coefficient in relation to the HPG gel. The proppant-setting rate was also determined in the gel and, the surfactant-based gel showed good static proppant support. One can conclude that obtained gel presents compatible characteristics when compared with the HPG gel, without the inconvenience of leaving insoluble residues in the well. (author)

  16. Radiolabeling hydroxyapatite nanorods as theranostic agents for osteosarcoma and bone metastases; Nanobastões de hidroxiapatita radiomarcados como agentes teranósticos para osteossarcomas e metastases ósseas

    Energy Technology Data Exchange (ETDEWEB)

    Cipreste, Marcelo Fernandes

    2017-07-01

    The theranostic nanobiomaterials have received much attention of the scientific community around the world since these materials can accumulate spontaneously and selectively in tumor regions, being internalized by its cells and promoting simultaneously the diagnosis and the treatment of many types of cancer. Among many nanobiomaterials able to act as theranostic systems, hydroxyapatite nanorods (HA) stand up as promising theranostic agents to act in the early stages of osteosarcoma due to their important properties such as biocompatibility, bioactivity and high affinity to bone tissues, being able to act as drug delivery systems and radioisotopes carries, among many others biomedical applications. Apatite structures such as HA have high stability and flexibility that make them susceptible to the doping process and the conjugation with other crystallographic phases to confer theranostic properties to the material. However, the performance of these materials depends directly on the ability of these nanoparticles to bind to tumor cells. The process of surface functionalization of hydroxyapatite improves the adhesion of this material to the cell membranes. An important property acquired by hydroxyapatite functionalized with folic acid refers to the active and preferential accumulation in tumor sites of osteosarcoma. The present work consists in the investigation of theranostic systems through the synthesis of hydroxyapatite nanorods doped with gadolinium and copper, and functionalized with folic acid (FA). The process of neutron activation enabled the production of the radioisotopes {sup 32}P, {sup 159}Gd and {sup 64}Cu in the HA lattice. A systematic study of the morphological and physicochemical characteristics was carried out, as well as the characterization of the magnetic and structural properties of these samples, including a study on the chemical interaction between folic acid, gadolinium, tenorite and the surface of nanoparticles. The synthesized materials were characterized by several techniques such as X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR) and X-ray fluorescence (EDX), elemental analysis (CHN), X-ray diffraction (XRD) with Rietveld refinement, electron microscopy images, nitrogen adsorption analysis, X-ray absorption fine structure spectroscopy (XAFS), thermogravimetric analysis, vibration sample magnetometry (VSM). All these characterizations were performed in order to study the general properties of these materials and the stability of the interactions between HA, FA, Gd and CuO. In addition, the biocompatibility of this system was tested on fibroblast cells and cytotoxicity was tested on osteosarcoma cells. The results indicated that the functionalization of hydroxyapatite with folic acid is possible and forms a stable interaction, the doping process of HA with Gd was successful as well as the synthesis of the Hydroxyapatite/Tenorite nanocomposite and the biological tests suggest that the materials are biocompatible and have the potential to treat osteosarcoma. (author)

  17. Niobium (V) doped bioceramics: evaluation of the hydrothermal route modified with citric acid and urea to obtain modified hydroxyapatite; Bioceramicas aditivadas com niobio (V): avaliacao da rota hidrotermica modificada com acido citrico e ureia para obtencao de hidroxiapatitas modificadas

    Energy Technology Data Exchange (ETDEWEB)

    Simomukay, E.; Souza, E.C.F. de; Antunes, S.R.M.; Borges, C.P.F.; Michel, M.D.; Antunes, A.C. [Universidade Estadual de Ponta Grossa (UEPG), Ponta Grossa, PR (Brazil)

    2016-01-15

    Synthetic hydroxyapatite (Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}; HA) has become a widely used ceramic material for bone reconstruction due to its biocompatibility with the bone tissue. This biocompatibility as well as other physical and chemical properties of the hydroxyapatite can be modified by the addition of different ions to its structure. Niobium (V) ion has not been commonly used in the hydroxyapatite synthesis. The objective of this study was to evaluate the use of hydrothermal route in the niobium (V) doped hydroxyapatite synthesis. The route used the niobium ammonium oxalate (NH{sub 4}H{sub 2}[NbO(C{sub 2}O{sub 4}){sub 3}].3H{sub 2}O) complex as a niobium (V) ion precursor. The addition of citric acid and urea in the hydrothermal route is used for the control of synthesis pH and precipitation rate. Pure sample and sample added with 5.3 ppm of niobium (V) ion were prepared. The coexistence of other phases besides the hydroxyapatite was not observed in any of the samples through the use of X-ray diffraction and infrared spectroscopy (FTIR) techniques. The FTIR technique revealed the presence of hydroxyapatite characteristic functional groups. The scanning electron microscopy analysis showed the formation of agglomerates composed of round particles, confirmed by the transmission electron microscopy technique. The X-ray fluorescence spectroscopic analysis detected the presence of niobium in the doped sample. The results showed that niobium (V) doped hydroxyapatite can be synthesized by means of hydrothermal route, which may be considered as huge potential for future application in bioceramics. (author)

  18. Synthesis of hydroxyapatite nanoparticles onto modified polypropylene surface to be used in bone tissue engineering; Sintese de nanoparticulas de hidroxiapatita na superficie de polipropileno modificado para utilizacao na engenharia de tecido osseo

    Energy Technology Data Exchange (ETDEWEB)

    Cellet, Thelma Sley P.; Pereira, Guilherme M.; Fragal, Elizangela H.; Rubira, Adley F., E-mail: thelmaspc@hotmail.com [Universidade Estadual de Maringa (UEM), Maringa, PR (Brazil). Departamento de Quimica; Companhoni, Mychelle V.P.; Nakamura, Celso V.; Ueda-Nakamura, Tania [Universidade Estadual de Maringa (UEM), Maringa, PR (Brazil). Departamento de Ciencias Basicas da Saude

    2015-07-01

    Chemical modification of polypropylene (PP) films can be explored to prepare innovative materials, for instance materials which can be used in tissue engineering application. The maleimide synthesis onto PP films was made for later polymerizes glycidyl methacrylate (GMA) and to grow up hydroxyapatite nanoparticles (n-HA) by biomimetization method (BM) in metastable simulated body fluid (SBF) for 7, 14 and 21 days. The modification steps were proved by infrared spectroscopy (FTIR) and the n-HA synthesis evidenced by X-ray diffractometry (XRD), scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS). PP films exposed to SBF for 14 and 21 days showed n-HA on all over the films surface. The interaction of pre-osteoblasts with the films after 48 hours was evaluated by SEM. The results demonstrate that cells on the surface of n-HA films showed spreading, and number of filopodia similar to the control, wherein the films with greater amount of n-HA appear to have higher filopodia connections between the cells and appear to have its surface covered with higher cell density. (author)

  19. Magnetic nanoparticles for cancer therapy; Nanoparticulas magneticas para o tratamento do cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bakuzis, Andris F. [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Instituto de Fisica

    2014-07-01

    terapeutico para esta inovadora tecnica nao invasiva e altamente localizada. Nesta palestra iremos discutir resultados da literatura e do nosso proprio grupo no tratamento de cancer usando a hipertermia magnetica. Diversos tipos de nanoparticulas magneticas sugeridas para esta aplicacao serao apresentados assim como a evolucao historica deste tratamento, que apesar de ter sido sugerido em meados da decada de 50, so mais recentemente foi aprovado na Europa para tratamento de seres humanos com tumores do cerebro. (author)

  20. Preparación y evaluación de una pasta ósea para aplicaciones médicas

    Directory of Open Access Journals (Sweden)

    Diana Marcela Escobar

    2009-01-01

    Full Text Available En este artículo se evalúan las características osteoinductivas y osteoconductivas de una pasta ósea preparada a partir de fosfato de calcio tipo hidroxiapatita, proteína morfogenética ósea y colágeno, capaz de inducir la diferenciación de células locales a células formadoras de hueso. La pasta preparada fue implantada en la región dorsal a nivel inter escapular, en 35 conejos de Raza Blanca de Nueva Zelanda, los cuales se distribuyeron en 7 grupos de evaluación (7, 14, 21, 28, 35, 42 y 49 días transcurridos estos tiempos se retiraron los implantes para ser evaluados histológicamente por microscopía óptica convencional y así caracterizar los diferentes elementos tisulares. Los resultados obtenidos se analizaron por método factorial de correspondencias múltiples con clasificación jerárquica, el cual mostró que se logra estimular la inducción de hueso en sitios ectópicos, teniendo actividad osteogénica, sin embargo, la alta cantidad de linfocitos y de eosinófilos, evidencian respuesta inflamatoria alrededor del implante.

  1. Nanoparticles of hydroxyapatite: preparation, characterization and cellular approach - An Overview

    Directory of Open Access Journals (Sweden)

    Alis Pataquiva Mateus

    2013-12-01

    Full Text Available Las síntesis de nanoestructuras se han aplicado para obtener hidroxiapatita a escala nanométrica para aplicaciones de implantes ortopédicos y dentales debido a su biocompatibilidad y a la similitud de las características con apatitas naturales, convirtiéndose en un material preferido para la comparación con hidroxiapatita a microescala. Este resumen presenta algunos de los procesos más estudiados para obtener hidroxiapatita en nanofase, enriquecido con los resultados de nuestro grupo y la información adicional e interesante sobre el rendimiento celular de nanohidroxiapatita in vitro.

  2. Application of Laplace transform for determination of albedo type boundary conditions for neutronic calculations; Aplicacao da transformada de Laplace para determinacao de condicoes de contorno tipo albedo para calculos neutronicos

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Claudio Zen

    2008-07-01

    In this dissertation we use the Laplace transform to derive expressions for nonstandard albedo boundary conditions for one and two non-multiplying regions at the ends of one dimensional domains. In practice, the fuel regions of reactor cores are surrounded by reflector regions that reduce neutron leakage. In order to exclude the reflector regions from the calculations, we introduce a reflection coefficient or albedo. We use the present albedo boundary conditions to solve numerically slab-geometry monoenergetic and multigroup diffusion equations using the conventional finite difference method. Numerical results are generated for fixed source and eigenvalue diffusion problems in slab geometry(author)

  3. New petroleum lifting concept - tubular asynchronous motor application for onshore petroleum exploitation - (MATAEOS); Nova concepcao para bombeamento de petroleo - motor assincrono tubular para aplicacao na extracao de oleo (petroleo) subterraneo - MATAEOS

    Energy Technology Data Exchange (ETDEWEB)

    Rossini, Wagner Marques; Cruz, Jose Jaime da; Sales, Roberto Moura [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Lab. de Automacao e Controle (LAC)], e-mail: freddie@lac.usp.br, e-mail: jaime@lac.usp.br, e-mail: roberto@lac.usp.br; Alvarenga, Bernardo Pinheiro de; Chabu, Ivan Eduardo; Cardoso, Jose Roberto [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica. Lab.de Eletromagnetismo Aplicado (LMAG)], e-mail: bernardo@eee.ufg.br, e-mail: ichabu@pea.usp.br, e-mail: cardoso@pea.usp.br

    2008-06-15

    This study presents the development of a prototype Tubular Asynchronous Motor Application for Onshore Petroleum Exploitation - (MATAEOS). The principal function of the motor is to directly drive a suction pump installed in the down hole of an onshore well. Considering the installation and operational difficulties and costs of a traditional production system, known as a ''the walking beam and rod string system'', the developed prototype is intended to be a technical and economically viable alternative. The results obtained show that the motor develops a constant lift force throughout the movement (or pumping) cycle, according to the dynamometric charts. The motor also presented an electro-mechanical performance higher than the traditional systems. Furthermore, the motor completely eliminates the need for the actual system's set of hoists. Generally, the results indicate that the motor can advantageously substitute surface mechanical systems. (author)

  4. Seeking tools for image fusion between computed tomography, structural and functional magnetic resonance methods for applications in neurosurgery; Ferramentas para fusao de imagens dos metodos de tomografia computadorizada, ressonancia magnetica e ressonancia magnetica funcional para aplicacao pre-neurocirurgica

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Liana Guerra Sanches da, E-mail: liana@einstein.br [Departamento de Diagnostico por Imagem, Hospital Israelita Albert Einstein - HIAE, Sao Paulo (SP) (Brazil); Amaro Junior, Edson [Faculdade de Medicina, Universidade de Sao Paulo - USP, Sao Paulo, SP (Brazil). Deptartamento de Diagnostico por Imagem; Instituto do Cerebro - InCe, Hospital Israelita Albert Einstein - HIAE, Sao Paulo, SP (Brazil)

    2012-04-15

    To evaluate tools for the fusion of images generated by tomography and structural and functional magnetic resonance imaging. Methods: Magnetic resonance and functional magnetic resonance imaging were performed while a volunteer who had previously undergone cranial tomography performed motor and somatosensory tasks in a 3-Tesla scanner. Image data were analyzed with different programs, and the results were compared. Results: We constructed a flow chart of computational processes that allowed measurement of the spatial congruence between the methods. There was no single computational tool that contained the entire set of functions necessary to achieve the goal. Conclusion: The fusion of the images from the three methods proved to be feasible with the use of four free-access software programs (OsiriX, Register, MRIcro and FSL). Our results may serve as a basis for building software that will be useful as a virtual tool prior to neurosurgery. (author)

  5. Chemical modification of HTPB for application as polymeric additives for diesel fuel. 1 - phenyl ethers; Modificacao quimicado PBLH para aplicacao como aditivos polimericos para oleo diesel. 1. eteres fenilicos

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Agne R.; Prezibella, Alysson M.; Ferraz, Fernando A.; Soldi, Rafael A.; Oliveira, Angelo R.S.; Cesar-Oliveira, Maria Aparecida F. [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica. Lab. de Polimeros Sinteticos

    2007-07-01

    The petroleum industry faces several problems related to the crystallization of paraffins, in petroleum and its derivatives, with the reduction of the service temperature. To solve this problem polymeric additives are used, of which the esters have been enough studied in several areas of the world, except in Brazil. In this work, this class of pour point depressant additives it was obtained through the chemical modification of Hydroxyl Terminate Polybutadiene (HTPB) that present a hydrocarbon chemical structure containing one double bound in each repetitive unit and hydroxyl groups of the primary and secondary allylic types - functional groups potentially reactive. The obtained products were characterized by Fourier transformed infrared spectroscopy and nuclear magnetic resonance, and they are being tested as additive for the pour point reduction of a diesel oil samples (REPAR-PETROBRAS). (author)

  6. Characterization of Paraiba state, Brazil, clays used for clearing of oil of frying for application as bio fuel; Cacterizacao de argilas do estado da Paraiba, Brasil, utilizaadas para clareamento de oleos de fritura usados para aplicacao como biobombustivel

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, E.P.; Oliveira, S.V. de; Medeiros, K.M. de; Araujo, E.M.; Fook, M.V.L. [Universidade Federal de Campina Grande (DEMa/UFCG), PB (Brazil). Dept. de Engenharia de Materiais], e-mail: elainepatriciaaraujo@yahoo.com.br

    2008-07-01

    The search for new sources of renewable energy order to minimize environmental impacts has led the scientists to develop new alternatives, such as the use of recycling of frying oils to produce biodiesel. The reuse of these oils has the advantage of obtaining a biofuel with the cost / benefit competitive. However, the conditions of post-consumer oils require treatment prior to its conversion the chemical (transesterification), removing solid particulate contaminants and adjusting its color using the clay of Paraiba. The use of biodiesel as fuel presents a reduction of levels of environmental pollution. This study aimed to characterize clay of Paraiba to be used in the clearing of frying oil. It was observed through the results of the Xray fluorescence (XRF) and infrared spectroscopy by Fourier Transform (FTIR), which the clays tested, have been effective in clearing of frying oils, making them similar to oil 'virgin'. (author)

  7. Deployment case study of a global applied 3D modeling process of pipe supports; Estudo de caso da aplicacao de uma ferramenta para automatizacao e controle do processo de modelagem de suportes para tubulacoes em maquetes 3D

    Energy Technology Data Exchange (ETDEWEB)

    Balbi, Diego Junca Gonzaga; Oliveira, Renato Fonseca; Pinto, Rogerio Dias [Promon Engenharia, Sao Paulo, SP (Brazil)

    2012-07-01

    An activity in engineering projects has been changed over the past two decades with regarding to working practices. Difficulties arising from the increasing complexity of projects, especially in industrial sectors, have taken this activity a constant search for new methods and tools which enable increased speed in performing tasks of daily life of the project. Currently, the development of these tools has been based on a friendlier interface to the end user, minimizing the need for extensive and repetitive training. Moreover, the industry responsible for this development of these kind of tools is still in the search for knowledge in order to explore the plain capabilities within wide projects on solutions offered. This article deals with one of these innovations on the spotlight, besides of being not a technology issue. It's based on the same basic platform available since the creation of models used together with databases. However, this new vision of work inserts one more specialty in the virtual designing of structures to support industrial pipes, as well as other design disciplines, nor taken advantage of these capabilities with regard to the generation of information, its control and management. (author)

  8. Application of of artificial neural networks for estimation of soil-plant transfer factor for {sup 137}Cs; Aplicacao de redes neurais artificiais para a previsao de valores do fator de transferencia solo-planta para {sup 137}Cs

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Anna Karla Gomes dos

    2016-07-01

    The knowledge of radionuclide behavior in soils is fundamental to calculate the dose due to food ingestion and to evaluate the risks of radioactive exposure of the population. This knowledge associated to the socio-economic characteristics of the affected region will set the radio protective measures to be taken in case of radioactive contamination of rural areas. The soil-plant transfer factor (TF) is the specific parameter value of radiological models to numerically integrate the dynamic processes that occur within the radionuclides in the soil plant system. This measurement, specific to each radionuclide and soil type, is defined ratio between a specific radionuclide activity in the edible part of the plant and its soil activity. However, the absence of linearity between soil concentrations and the measurements in plants indicate the complexity of the transfer process of radionuclide from soil to a plant, making it difficult to forecast the TF ratio in a specific scenario. One of the main radionuclides associated to nuclear accidents impacting rural areas is {sup 137}Cs. This is one of the most worrisome radionuclides because of its physiochemical properties and its chemical similarity with potassium (K) and its extended physical mid-life (t1/2 = 30,17 years) that allows great environmental dispersion, ecological mobility and environmental endurance. Radiological studies related to {sup 137}Cs transfer factor show that pedological parameters that considerably explain the behavior of {sup 137}Cs in soil-plant system are: exchangeable K, clayed minerals, organic matter content and pH in soils. In this work, the computational method of artificial neural network (ANN) was applied to evaluate the possibility to forecast the TF of {sup 137}Cs in cereals, associated to pedological parameters considered potential indicators of its phyto availability: cationic exchange capacity (CEC), exchangeable K and pH. This study demonstrated that the ANN, having only as entry data the pedological parameters pH, CEC and exchangeable K, was capable of estimating TF soil-plant values in cereals for {sup 137}Cs with deviations inferior to 6% in almost 86% of the cases, showing the availability of the ANN use as a tool to predict the soil-plant transfer factor values for {sup 1}3{sup 7}Cs. The results of this emphasize the influence of these pedological parameters in the control of the {sup 137}Cs soil-plant transfer process. The previous knowledge of transfer factors, enable to infer the degree of radio vulnerability of a soil that's potentially subject to radioactive contamination, which will help in the planning of emergency treatment in short, medium and long term in rural areas close to nuclear plants, as well as the selection of adequate places for the waste storage and nuclear installations. (author)

  9. Evaluation of mechanical and electrical properties for an aluminium alloy thermo resistant for application in electrical cables and wires; Avaliacao das propriedades mecanicas e eletricas para uma liga de aluminio termorresistente para aplicacao em fios e cabos eletricos

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, M.A.; Reis, W.L.S.; Souza, A.T.M.D.; Quaresma, J.M.V. [Universidade Federal do Para, Belem, PA (Brazil)

    2010-07-01

    With the constant growth of brazilian industry and, consequently, the demand for electric power, realized the need to develop new metal alloys for use in wire and cable transmission and distribution of electricity to support the high temperatures which will be submitted. this study is based on the modification of aluminum by contents of Zr. the alloys were cast into ingot shaped {sup u,} after machined to a diameter of 18 mm, were homogenized and cold-worked (rolled). subsequently underwent a series of heat treatments at temperatures (230 degree c, 310 degree c and 390 degree c) for one hour in order to obtain the recrystallization temperature of alloys and demonstrate its potential for thermo resistant. With the inclusion of increasing contents of Zr, the alloy showed a higher recrystallization temperature and an increase in their limit of tensile strength. (author)

  10. para palmito

    Directory of Open Access Journals (Sweden)

    Francisco Paulo Chaimsohn

    2007-01-01

    Full Text Available Densidades de siembra, arreglos espaciales y fertilización en pejibaye (Bactris gasipaes cv Diamantes-10 para palmito. La investigación se llevó a cabo en la Estación Experimental Los Diamantes (Guápiles, Costa Rica, el 3 de octubre del 2003, cuyo objetivo fue la evaluación del efecto de diferentes densidades de siembra (3.333, 5.000 y 6.666 plantas/ha, arreglos espaciales, y diversos métodos de fertilización (química, orgánica, sobre el crecimiento de las plantas de pejibaye para producción de palmito. Se consideraron las variables diámetro y altura del tallo primario y el número de hojas y rebrotes como indicadores de producción. El período de evolución abarcó sólo los primeros 25 meses de crecimiento en el campo. El número de hojas, la altura y el diámetro del tallo no mostraron diferencias de respuesta relevantes. Sólo el número de rebrotes disminuyó al aumentar la densidad de la población, cuando se midió a los 15 meses de edad. El efecto de la fertilización se hizo evidente después de la primera cosecha, realizada a los 20 meses, debido al aumento de la competencia entre plantas, ahora más desarrolladas. Fue entonces cuando la fertilización química indujo la producción de un mayor número y vigor de los rebrotes. Sin embargo, las prácticas evaluadas 25 meses después de la siembra, no habían infl uido hasta ese momento en el número de palmitos cosechados, ni tampoco había afectado las características físicas de los sectores foliar y caulinar del palmito.

  11. Study of biocompatible properties of polymeric scaffolds derived from vegetable oils for application in tissue engineering; Estudo das propriedades biocompativeis de arcaboucos polimericos derivados de oleos vegetais para aplicacao na engenharia de tecidos

    Energy Technology Data Exchange (ETDEWEB)

    Baratela, Fernando Jose Costa

    2015-11-01

    Tissue engineering and regenerative medicine have as main objective the morphologic/functional reestablishment of injured tissues and organs using cells, scaffolds, stem cells and control of immunological/biochemical responses promoted by the body. In addition, materials science seeks to develop biocompatible biomaterials that do not promote unwanted immune responses and provide the re-establishment of the functions of the tissue/organ. Polymers of natural origin stand out as biomaterials to resemble biological macromolecules, similarity to the extracellular matrix, reduced chance of inflammation and chronic pacing low or no toxicity. This study aimed the development of macromolecular arrays originated from epoxidized soybean oil (OSE), analyzing the relationship between the chemical structure/biological activity of the macromolecular arrays for use as biomaterials in tissue engineering. The synthesis of OSE was performed through the oil chemical route, whose efficiency was determined by infrared spectroscopy and the reaction yield of 85%, determined by nuclear magnetic resonance spectroscopy. From the analysis by differential scanning calorimetry, it was detected a decrease of the glass transition temperature of the epoxidized soybean oil polymer (POSE) compared with OSE, suggesting an increase of the growth of polymer chains of POSE. Thermogravimetric analysis was performed to define the OSE degradation profile, which degrades in two steps. The POSE degrades in just one step and shows higher thermal stability by the increased molecular interactions. The hydrophilicity and crosslinking of POSE was promoted by the addition of 2-hydroxyethyl methacrylate (HEMA) with the monomer grafting by gamma irradiation. The results showed an increased mechanical stability, gelation and water absorption with the HEMA content increasing. Finally, the degree of crystallinity for such polymers grafted with HEMA was 27.5%, estimated by X-ray diffractometry. The second stage was characterized by (I) developing POSEs with the grafting of HEMA in the proportions OSE / HEMA 90:10 and 65:35 irradiated by gamma rays at doses of 50 and 100kGy, (II) physico-chemical characterization of POSE-HEMA and (III) analysis of biological materials. By infrared spectroscopy, it was detect the epoxidized regions of POSE, as well as the successful grafting of the monomer HEMA concentrations with all radiation doses. By differential scanning calorimetry, the activation energy was calculated (E{sub a}) of the polymers. The crystallinity of the material was defined by X-ray diffraction, showing tendency of amorphous material as well as a small percentage of the increase in crystallinity with increasing intensity of radiation doses during this synthesis and a decrease in crystallinity with the increasing concentration of HEMA. The analysis of the samples did not show cytotoxicity on POSE-HEMA and confirmed the efficiency of polymer washings to remove the processing waste. The analysis of hemocompatibility showed any platelet adhesion and the cell growth on the scaffolds was positive. From the results obtained in this research, we concluded by the potential use of POSE-HEMA in tissue engineering. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  13. Synthesis and ceramic processing of zirconia alumina composites for application as solid oxide fuel cell electrolytes; Sintese e processamento de compositos de zirconia-alumina para aplicacao como eletrolito em celulas a combustivel de oxido solido

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Rafael Henrique Lazzari

    2007-07-01

    The global warmness and the necessity to obtain clean energy from alternative methods than petroleum raises the importance of developing cleaner and more efficient systems of energy generation, among then, the solid oxide fuel cell (SOFC). Cubic stabilized zirconia (CSZ) has been the most studied material as electrolyte in SOFC, due to its ionic conductivity and great stability at operation conditions. However, its low fracture toughness difficulties its application as a thin layer, what could lead to an improvement of cell efficiency. In this sense, the alumina addition in CSZ forms a composite, which can shift its mechanical properties, without compromising its electrical properties. In this work, coprecipitation synthesis route and ceramic processing of zirconia-alumina composites were studied, in order to establish optimum conditions to attain high density, homogeneous microstructure, and better mechanical properties than CSZ, without compromising ionic conductivity. For this purpose, composites containing up to 40 wt % of alumina, in a 9 mol % yttria-stabilized zirconia (9Y-CSZ) matrix were evaluated. In order to optimize the synthesis of the composites, a preliminary study of powder obtaining and processing were carried out, at compositions containing 20 wt % of alumina, in 9Y-CSZ. The ceramic powders were characterized by helium picnometry, X-ray diffraction, scanning electronic microscopy, transmission electronic microscopy, thermogravimetry, differential scanning calorimetry, granulometry by laser diffraction and gas adsorption (BET). The characterization of sinterized compacts were performed by X-ray diffraction, scanning electron microscopy, optical microscopy, density measurements, Vickers indentation and impedance spectroscopy. The obtained results show that the alumina addition, in the 9Y-CSZ matrix powders, raises the specific surface area, promotes deagglomeration of powders and elevates the oxides crystallization temperature, requiring higher energetic thermal treatments to attain high densities. In relation to the sintered products, it was confirmed the excellent homogeneity and crystallinity of microstructure provided by the chosen route, the restriction of grain growth by alumina addition, raise of hardness and fracture toughness, and higher ionic conductivity, even tough a lower bulk conductivity. These results indicate that the addition of 5 wt % alumina in CSZ matrix allows the application of this material as solid oxide fuel cell electrolytes, due to its better fracture toughness and ionic conductivity, compared to yttria-stabilized cubic zirconia ceramics. (author)

  14. Application of the electrophoretic deposition technique for obtaining Yttria-stabilized zirconia tubes; Aplicacao da tecnica de deposicao eletroforetica para a obtencao de tubos ceramicos de zirconia-itria

    Energy Technology Data Exchange (ETDEWEB)

    Caproni, E.; Muccillo, R., E-mail: ecaproni@gmail.com, E-mail: muccillo@usp.br [Centro de Ciencia e Tecnologia de Materiais, Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2012-01-15

    The electrophoretic deposition (EPD) is recognized as the most versatile technique for processing particulate materials, due to low cost, deposition in minutes and forming of pieces with complex geometry shapes. In this work an experimental setup for the simultaneous conformation of 16 ceramic tubes by EPD was built. Bimodal submicron Yttria-stabilized zirconia particles were deposited into graphite electrodes, after suitably adjusting the rheological characteristics of the suspension in isopropanol. After graphite burning and YSZ sintering at 1500 deg C, the ceramic tubes were characterized by X-ray diffraction, scanning probe microscope, impedance spectroscopy and electrical response as a function of oxygen content. Small dense one end-closed ceramic tubes, fully stabilized in the cubic phase, were successfully obtained by the EPD technique, showing the ability of that technique for processing large quantities of tubular solid electrolytes with electrical response to different amounts of oxygen according to the Nernst law (author)

  15. Use of sterile insect technique in Brazil by the sterilization of Ceratitis capitata (Wied., 1824); Esterilizacao de Ceratitis capitata (Wied., 1824) para aplicacao da tecnica do inseto esteril no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Okeese, G.O.; Kitomer, T.J.; Gayaradus, L.B.; Etrigan, M. [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)]. E-mail: jamuga@cena.usp.br; Jansen, C.W.J.H.; Houlahar, H.L. [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil)

    2006-07-01

    The Sterile Insect Technique is a method of pest control allowed in Integrated Pest Management programs in fruit growing, where sterile insects released compete in mate process against fertile wild ones, generating a gradative population reduction. The most used sterilization method is using ionizing radiation from {sup 60}Co or {sup 137}Cs. For efficient application of SIT, an important item is the sterilizing dose. This must be as lower as possible in order to preserve insect behavior. In this work, it was studied the reproductive potential of fruit fly Ceratitis capitata, tsl VIENNA 8 strain, irradiated with different doses of gamma radiation. This strain has been used in population suppression programs at fruit-growing areas from Northeast of Brazil, through a partnership between CENA and Bio factory MOSCAMED Brazil, intending only sterile male releases. Radiation source used was a {sup 60}Co irradiator, with 17.2 x 1012 Bq. Individualized couples were distributed in a randomized delineament with 10 replicates for each treatment and eggs were collected for fifteen days. With 9 and 10 days old, pupae were irradiated with doses ranging from 30 to 120 Gy. All averages of emerged adult's percentages were higher than 90%. In regards to fecundity, different doses did not affect the number of eggs laid, being the overall mean around 30 eggs/couple/day. Fertility data showed that as radiation dose increases, sterility increases. It was concluded that the dose of 90 Gy can be used in Brazil, since to SIT programs a dose is chosen witch prevents an egg hatch higher than 1%. (author)

  16. Project scheduling with resources constraints: application in the equipment production for the oil industry; Scheduling de projetos com restricao de recursos: aplicacao na producao de equipamentos para a industria de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Carolina A.O.; Ferreira Filho, Virgilio J.M. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE)

    2008-07-01

    One of the essential steps in the main scope Project Management is the Time Management made by the planning and control of the project schedule. In this work is presented the resource constrained scheduling problem beyond its mathematical formulation and a review of papers about this issue. In sequence is presented a practical example of this model considering a simplified model of an engineering project schedule of oil production equipment. The results obtained with the model application are shown and the conclusions about the work with resource constrained scheduling problems. (author)

  17. Preparation of PtRu/C anode electrocatalysts using gamma radiation for methanol electro-oxidation; Preparacao de eletrocatalisadores PtRu/C utilizando radiacao gama para aplicacao como anodo na oxidacao direta de metanol

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Dionisio Fortunato da

    2006-07-01

    Pt Ru/C (carbon-supported Pt Ru nanoparticles) anode electrocatalysts were prepared using radiolytic process (gamma radiation) and tested for methanol electro-oxidation. In this process, water/2-propanol and water/ethylene glycol solutions containing the metallic ions and the carbon support were submitted to gamma radiation under stirring. The water/alcohol ratio (v/v) and the total dose (kGy) were studied. A nominal Pt Ru atomic ratio of 50:50 were used in all experiments. The electrocatalysts were characterized by energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry (CV). The electro-oxidation of methanol was studied by cyclic voltammetry using the thin porous coating technique. The electrocatalysts prepared in water/2-propanol showed crystallite size in the range of 3-5 nm and Pt Ru atomic ratio of 50:50. The electrocatalysts prepared in water/ethylene glycol showed crystallite size (2-3 nm) smaller than the ones obtained in water/2-propanol, however, the Pt Ru atomic ratios obtained were approximately 80:20, showing that only part of ruthenium ions were reduced. For methanol oxidation the electrocatalytic activity depends on the water/2-propanol and water/ethylene glycol ratio used in the reaction medium. The electrocatalysts prepared in water/2-propanol showed inferior performance to the ones prepared in water/ethylene glycol, which showed similar or superior performances (amperes per gram of platinum) to the commercial electrocatalyst from E-TEK. (author)

  18. Fabrication and electrical characterization of polyaniline-silicon heterojunction for gamma radiation dosimetry application; Fabricacao e caracterizacao eletrica de heterojuncoes de polianilina - silicio para aplicacao em dosimetria de radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Laranjeira, Jane Maria Goncalves

    2004-08-15

    In this work a technique has been developed to fabricate high quality polyaniline-silicon heterojunction diodes for use as gas and/or ionizing radiation sensors. Polyaniline thin films (40 nm thick) produced by spin-coating on silicon substrates, were the active part of the junction structure. The devices presented excellent reproducibility of their electrical characteristics with high rectification ratio, 60,000 at {+-}1.0 V, and typical reverse current at - 1.0 V of 3 nA at 295 K. A G/I x G plot has been used to analyze the current-voltage characteristics, yielding typical series resistance of 4 k{omega} {+-} 5% and ideality factor in a range of 1,9 {+-} 0.5%. The heterojunction diode presents high sensitivity to gamma radiation in the dose range of 3 x 10{sup -2} to 7 kGy with a linear response in the forward and reverse bias. The excellent electrical characteristics together with the linear response with the dose, strongly suggest the application of this device for spectrometry or dosimetry of high doses of gamma radiation. These devices presented high sensitivity to gas moistures such as ammonia, nitric acid and trichloroethylene. In both cases the sensitivity was observed through shifts of the current-voltage curves, which can be easily monitored to provide a calibration curve of the sensor either as a radiation dosimeter or as a gas sensor for use in applications for gas monitoring or radiation dosimetry. Several aspects of the reliability physics of silicon-polyaniline heterojunction, such as degradation effects induced by local heating, charge trapping and temperature changes, have been discussed. These results further confirm the quality of the devices electrical characteristics and their suitability for radiation and gas sensors applications. Another interesting results presented in this work was the use of polyemeraldine nanofilms (thickness in the range 30-50 nm) deposited by 'spin coating' on glass substrates as an optical dosimeter for gamma radiation based on the color change of the polymer. The nanofilms devices were characterized by UV visible absorption spectroscopy. The deep blue color, characteristic of undoped polyaniline films before irradiation, becomes subsequently green as the film is being irradiated, and the film absorption coefficient exhibits a linear dependence with the logarithm of the irradiation dose from I to 10 kGy. (author)

  19. Study of corrosion resistance of AISI 444 ferritic stainless steel for application as a biomaterial; Estudo da resistencia a corrosao do aco inoxidavel ferritico AISI 444 para aplicacao como biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Rogerio Albuquerque

    2014-09-01

    Ferritic stainless steels are ferromagnetic materials. This property does not allow their use in orthopedic prosthesis. Nevertheless, in some specific applications, this characteristic is very useful, such as, for fixing dental and facial prostheses by using magnetic attachments. In this study, the corrosion resistance and cytotoxicity of the AISI 444 ferritic stainless steel, with low nickel content, extra-low interstitial levels (C and N) and Ti and Nb stabilizers, were investigated for magnetic dental attachments application. The ISO 5832-1 (ASTM F-139) austenitic stainless steel and a commercial universal keeper for dental attachment (Neo-magnet System) were evaluated for comparison reasons. The first stainless steel is the most used metallic material for prostheses, and the second one, is a ferromagnetic keeper for dental prostheses (NeoM). In vitro cytotoxicity analysis was performed by the red neutral incorporation method. The results showed that the AISI 444 stainless steel is non cytotoxic. The corrosion resistance was studied by anodic polarization methods and electrochemical impedance spectroscopy (EIS), in a saline phosphate buffered solution (PBS) at 37 °C. The electronic properties of the passive film formed on AISI 444 SS were evaluated by the Mott-Schottky approach. All tested materials showed passivity in the PBS medium and the passive oxide film presented a duplex nature. The highest susceptibility to pitting corrosion was associated to the NeoM SS. This steel was also associated to the highest dopant concentration. The comparatively low levels of chromium (nearly 12.5%) and molybdenum (0.3%) of NeoM relatively to the other studied stainless steels are the probable cause of its lower corrosion resistance. The NeoM chemical composition does not match that of the SUS444 standards. The AISI 444 SS pitting resistance was equivalent to the ISO 5832-1 pointing out that it is a potential candidate for replacement of commercial ferromagnetic alloys used in dental prosthesis. (author)

  20. Energy choice for textile industry: application of multi-criteria methods to the case of Ceara state (Brazil); Escolha de insumo energetico para o setor da industria textil: aplicacao de modelo multicriterio ao caso do Ceara

    Energy Technology Data Exchange (ETDEWEB)

    Rabelo, Clarice A.C.; Arruda, Joao Bosco F [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Nucleo de Pesquisa em Logistica, Transportes e Desenvolvimento

    2004-07-01

    Brazilian energy sector has faced a series of transformations that have influence on national industry. The trial of economy globalization and the new energy sources Also available and output techniques created a more competitive business environment, where not only financial aspects are considered in industrial practices. In such environment, the industry seek for more efficient production techniques and greater importance given to environmental issues are responsible for making the decision processes associated to industrial activities more complex. In this context, the energy utilized by industry represents an important aspect of business course, justified by governmental concerns on attending all existing thermal energy demand. This paper aim is to support the decision process concerned to the choice of the best energy source to be applied in the industry. In order to reach such goal, a decision model was built based on multi criteria techniques applied to the case of textile industry in Ceara State. This sector is also one of the biggest natural gas consumers in Ceara, which has influenced on its choice in order to attend to a second goal of this paper: to focus the natural gas applications and support a greater insertion of this fuel in the market. (author)

  1. Proficiency tests for evaluation of the {sup 99}Tc{sup m} measurements in the nuclear medicine; Aplicacao de teste de proficiencia para avaliacao da medicao de {sup 99}Tc{sup m} na medicina nuclear

    Energy Technology Data Exchange (ETDEWEB)

    Iwahara, Akira; Tauhata, Luiz; Oliveira, Antonio Eduardo de, E-mail: iwahara@ird.gov.b, E-mail: tauhata@ird.gov.b, E-mail: aedu@ird.gov.b [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Nicoli, Ieda Gomes, E-mail: ieda@ird.gov.b [Comissao Nacional de Energia Nuclear (CNEN/DF), Brasilia, DF (Brazil). Escritorio de Brasilia; Alabarse, Frederico Gil; Xavier, Ana Maria, E-mail: falabarse@ird.gov.b, E-mail: axavier@ird.gov.b [Comissao Nacional de Energia Nuclear (ESPOA/CNEN-RS), Porto Alegre, RS (Brazil). Escritorio de Porto Alegre

    2009-07-01

    This work performs the performance evaluation of 55 Brazilian nuclear medicine services in activity measurement of radiopharmaceutical containing {sup 99}Tc{sup m}. Proficiency tests based on the acceptance criteria of the Regulation ISO/IEC Guide 43-1 and on the accuracy of the brazilian Regulation CNEN-NN-3.05 were applied in 63 results of activity measurements in radionuclide calibrators used by those services. The performance services has shown that the criteria of the ISO/IEC 43-1, nevertheless to be more restrictive, presents results very consistent with the accuracy criteria requested by the Brazilian regulation

  2. Synthesis and characterization of sulfonic acid membranes based on interpenetrating polymer networks for application in fuel cells; Sintese e caracterizacao de membranas sulfonadas baseadas em redes polimericas interpenetrantes para aplicacao em celulas a combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Blanco, Lyzed Toloza; Loureiro, Felipe A.M.; Rocco, Ana Maria [Grupo de Materiais Condutores e Energia, Escola de Quimica, Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)], e-mail: amrocco@eq.ufrj.br; Pereira, Robson Pacheco [Instituto de Ciencias Exatas, Universidade Federal Fluminense (UFF), Volta Redonda, RJ (Brazil)

    2011-07-01

    In the present work, the synthesis and characterization of sulfonic membranes based on interpenetrating polymer networks (IPN). In order to obtain such systems, the diglycidyl ether of bisphenol A (DGEBA) was polymerized in presence of polyethyleneimine (PEI). These membranes were submitted to sulfonation reactions, originating IPN-SO{sub 3}H membranes. The characterization by FTIR evidenced the formation of a Semi-IPN structure, while sulfonation reactions resulted in systems containing -SO{sub 3}H groups covalently bonded to the chains. The membranes exhibited water retention up to 200 degree C, in a temperature range sufficient for application in PEMFC under hydration. (author)

  3. Application of neutron activation analysis for the determination of essential elements in egg samples; Aplicacao da analise por ativacao com neutrons para a determinacao de elementos essenciais em amostras de ovos

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Bruna G.; Maihara, Vera A.; Avegliano, Roseane P., E-mail: brunagabrielegomes@gmail.com, E-mail: vmaihara@ipen.br, E-mail: pagliaro@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The eggs are among the twenty foods consumed by the population of the five major regions of Brazil. Among the types of eggs, there are differences in nutritional value, which can vary according to the food of the bird. This study evaluating the elements Cl, K, Mg, Mn and Na considered essential micronutrients in food, because they are fundamental in several metabolic processes necessary for the maintenance and training of the human body. We analyzed three types of eggs: egg whites, of the quail, and the colonial in cooked and raw form, using the Instrumental Neutron Activation Analysis method (INAA). The egg samples were lyophilized and pulverized before analysis. To validate the methodology, reference materials NIST RM 8415 Whole Egg Powder and NIST SRM 1567 Wheat Flour were analyzed. The samples, reference materials and standards of the elements were irradiated for 20 seconds under a thermal neutron flux of 6,6x10{sup 12} cm -2 s -1 in the nuclear research reactor IEA-R1 of IPEN-CNEN / SP. The results were consistent with the values of the Brazilian Table of Food Composition (TACO)

  4. International oil and natural gas demand projections: an econometric model for 2008-2030; Projecao das demandas mundiais de petroleo e de gas natural: aplicacao de um modelo agregado para o periodo 2008-2030

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Giovani; Aragao, Amanda; Valle, Ricardo Nascimento e Silva do [Empresa de Pesquisa Energetica (EPE), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    This study forecasts the world oil and gas demands for 2008-2030 by applying econometric formulations. The basic variables are world GDP and Brent price. The forecast assumptions are: sound world economic growth remains, despite falling rates during the period; Brent prices continue high, but in a lower level, in 2006 constant prices, in harmony with Energy Information Administration reference scenario. Findings show that, should assumptions prove to be correct, world oil and gas demands will reach 118 million bbl/d and 5 trillion cubic meters in 2030, respectively. In other words, world oil demand will grow at 1.4% per year, while world gas demand will increase at 2.5% per year. Although such figures are similar to those from other institutions (EIA, IEA and OPEC), structural changes in oil and gas markets, catalyzed by high oil prices and energy and environmental policies, may reduce forecast strength of the specifications proposed. (author)

  5. Synthesis and characterization of Pt-Sn-Ni alloys to application as catalysts for direct ethanol fuel cells; Sintese e caracterizacao de ligas de Pt-Sn-Ni para aplicacao como caztalisadores em celulas a combustivel do tipo DEFC

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.L. da; Correa, P.S.; Oliveira, E.L. de; Takimi, A.S.; Malfatti, C.F., E-mail: celia.malfatti@ufrgs.b [Universidade Federal do Rio Grande do Sul (LAPEC/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica. Lab. de Pesquisa em Corrosao; Radtke, C. [Universidade Federal do Rio Grande do Sul (IQ/UFRGS), Porto Alegre, RS (Brazil). Inst. de Quimica

    2010-07-01

    Direct ethanol fuel cells (DEFCs) have been the focus of recent research due its application in mobile energy sources. In order to obtain the maximum efficiency from these systems, it is necessary the total ethanol oxidation, which implies in C-C bond break. Different catalysts described in literature are employed with this intent. This work consists in studying PtSnNi catalysts supported on carbon Vulcan XC72R, to application in DEFCs. Thus, it was used the impregnation/reduction method, varying the atomic proportion among Pt, Sn and Ni. The alloys were characterized by X-Ray Diffraction, Cyclic Voltammetry and Transmission Microscopy. Preliminary results show that predominant structure on the catalysts is the face centered cubic platinum and the densities currents are dependent on the platinum amount. (author)

  6. Application of gamma irradiation for incorporation of rubber powder in the formulations EPDM and NBR rubber; Aplicacao da radiacao gama para incorporacao do po de borracha em formulacoes de borracha EPDM e nitrilica

    Energy Technology Data Exchange (ETDEWEB)

    Kiyan, Ludmila de Ysasa Pozzo

    2014-07-01

    The natural decomposition of rubber is a very slow process due to its three-dimensional network formed by vulcanized crosslinked structures becoming extremely difficult to reprocess this material. The present work aims to study the application of gamma irradiation as devulcanization process for material reuse/recycling. The interactions of elastomers with ionizing radiation of a gamma source were investigated and the changes in physicochemical properties of the materials were evaluated. Formulations of NBR (acrylonitrile - butadiene) and EPDM (ethylene - propylene - diene terpolymer) from the rubber industry were crosslinked by conventional sulfur-based mixing. Master - batch was processed with rubber powder (industrial waste) and virgin rubber. The raw material (master batch) was irradiated in {sup 60}Co source at doses of 50, 100, 150 kGy and dose rate of 5 kGy h{sup -1} at room temperature. The irradiated material was incorporated in classical sulfur-based formulations. The formulations were characterized by: infrared spectroscopy (FTIR), thermal analysis (TG and DTG), tensile strength, elongation at break, hardness, abrasion resistance, rheometry and swelling. The results showed a predominance of chain scission at a dose of 50 kGy for EPDM rubber. For nitrile predominance of chain scission was observed at a dose of 100 kGy. These results show the possibility of the use of gamma radiation for the reuse/recycling of EPDM and nitrile rubbers. (author)

  7. Application of different methodologies in the preparation of organic matrices for determination of trace elements by differential pulse anodic stripping voltammetry; Aplicacao de diferentes metodologias na preparacao de matrizes organicas para a determinacao voltametrica de elementos traco

    Energy Technology Data Exchange (ETDEWEB)

    Sisti, Cristina

    2001-07-01

    The determination of trace elements in food samples is of great importance for the human health, considering the factors of essentiality and toxicity. On the other hand, the chemical analysis is largely affected for the steps of sample preparation; laboratory contamination of the sample and the reagents or still volatilization and losses of the elements. If these parameters are not controlled the achieved precision and accuracy could be low. In this work, the content of zinc, cadmium, lead and copper was determined in adults diet samples collected by duplicate portion technique and bovine liver, applying the differential pulse anodic stripping voltametry - (DP-ASV) technique. In the digestion of the matrices in acid medium, conventional methodologies were used, conductive heating in open recipients and equipment with microwaves source in open and closed vessels. The best procedure was the sample digestion by microwaves, in closed vessels and the other treatments made in controlled atmosphere with hood laminar-airflow class 100. The established methodology was validated with the use of a certified sample as reference (NIST - bovine liver 1577b). (author)

  8. Application of gamma radiation on disinfestation feed grain based food for domestic animals; Aplicacao da radiacao gama na desinfestacao de racoes a base de graos para alimentacao de animais domesticos

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Amanda Cristina Oliveira

    2009-07-01

    This study aimed to realize a survey to identify the associated insects to feed the city Sao Paulo / SP and also to assess the effect of gamma radiation on food ration for domestic animals infested by pests. Samples of 20 stores, 'Pet Shop' in different regions in Sao Paulo / SP were subjected to trials of 1 and 45 days for collection of insects with the aid of plastic tray and screens of different sizes. The species Sitophilus zeamais, Cryptolestes ferrugineus, Lasioderma serricorne and Oryzaephilus sp. showed a higher frequency. In assessing the effects of gamma radiation we used samples of maize, sunflower seeds and mix for rodents infested with adults of the species Sitophilus zeamais, Lasioderma serricorne and Plodia interpunctella, after the period of 7 to 10 days the insects were removed and samples subjected to increasing doses of gamma radiation. The species Sitophilus zeamais and Lasioderma serricorne subjected doses from 0,25 to 1,50 kGy and species Plodia interpunctella doses from 0,10 to 2,0 kGy. After 40 days of irradiation was evaluated the number of insects emerged. The results of bioassays with Sitophilus zeamais and with Lasioderma serricorne demonstrated that doses starting at 0,5 kGy was sufficient to cause mortality of eggs and newly emerged larvae. The results with Plodia interpunctella from the 1,5 kGy, hasn't emerged adult insects, concluding that these doses were sufficient to cause mortality of eggs and larvae. (author)

  9. Procedures development and methodology of control for application of good manufacture practices (GMP) on human blood irradiation; Desenvolvimento de procedimentos e metodologia de controle para aplicacao de boas praticas de fabricacao (BPF) na irradiacao de sangue humano

    Energy Technology Data Exchange (ETDEWEB)

    Boghi, Claudio

    2008-07-01

    The irradiation of human blood is used to avoid the TA-GVHD (transfusion-associated graft-versus-host-disease), a rare but devastating adverse effect of leukocytes present in blood components for a immunocompetent transfusion recipients. Usually this irradiation practice is performed to a physical elimination of leukocytes. The implementation of the procedures will assure that the properly dose in a range of 25 Gy to 50 Gy will be delivered to the blood in the bag collected in a blood tissue bank. The studies of the procedures in order to establish a GMP (Good Manufacturing Practices) were developed under the guidelines of the standard ISO 11137 - Sterilization of health care products - Requirements for validation and routine control - Radiation sterilization. In this work, two dosimetric systems were used for dose mapping during the studies of irradiator qualification, loading pattern, irradiation process validation and auditing. The CaS0{sub 4}:Dy dosimeter presented difficulties concerning to uncertainty on dose measurement, stability, traceability and calibration. The PMMA and Gafchromic dosimetric systems have shown a better performance and were adopted on studies of irradiators qualification that are necessary to implementation of GMP. The irradiation tests have been done in a Gammacell 220 irradiator. The developed procedures can be adapted for different kinds of gamma irradiators, allowing implanting a quality assurance program and a GMP for blood irradiation. (author)

  10. Application of relative permeability modifier additives to reduce water production in different formations; Aplicacao de aditivos modificadores de permeabilidade relativa para reducao da producao de agua em diferentes formacoes

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Ricardo C.B.; Torres, Ricardo S.; Pedrosa Junior, Helio; Dean, Gregory [BJ Services do Brasil Ltda., RJ (Brazil)

    2004-07-01

    Today most oil companies would be better described as water companies. Total worldwide oil production averages some 75 million barrels per day and, while estimates vary, this is associated with the production of 300 - 400 million barrels of water per day. These values of approximately 5 - 6 barrels of water for every barrel of oil are quite conservative. In the United States, where many fields are depleted, the ratio of water-to-oil production is closer to 9 to 1. In some areas around the world, fields remain on production when the ratio is as high as 48 to 1. Numerous strategies, both mechanical and chemical, have been employed over the years in attempts to achieve reduction in water production. Simple shut-off techniques, using cement, mechanical plugs and cross-linked gels have been widely used. Exotic materials such as DPR (disproportionate permeability reducers) and or new generation of relative permeability modifiers (RPM) have been applied in radial treatments with varying degrees of success. Most recently 'Conformance Fracturing' operations have increased substantially in mature fields as the synergistic effect obtained by adding a RPM to a fracturing fluid have produced increased oil production with reduced water cut in one step, consequently eliminating the cost of additional water shut off treatment later on. This paper presents laboratory testing and worldwide case histories of applications of various RPM materials, at different permeability and temperatures. The paper also describes technical design and operational methodology that we believe to have a significant impact in the development strategies of many fields worldwide. (author)

  11. Detection of outliers by neural network on the gas centrifuge experimental data of isotopic separation process; Aplicacao de redes neurais para deteccao de erros grosseiros em dados de processo de separacao de isotopos de uranio por ultracentrifugacao

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Monica de Carvalho Vasconcelos

    2004-07-01

    This work presents and discusses the neural network technique aiming at the detection of outliers on a set of gas centrifuge isotope separation experimental data. In order to evaluate the application of this new technique, the result obtained of the detection is compared to the result of the statistical analysis combined with the cluster analysis. This method for the detection of outliers presents a considerable potential in the field of data analysis and it is at the same time easier and faster to use and requests very less knowledge of the physics involved in the process. This work established a procedure for detecting experiments which are suspect to contain gross errors inside a data set where the usual techniques for identification of these errors cannot be applied or its use/demands an excessively long work. (author)

  12. Fabrication and electrical characterization of polyaniline-silicon heterojunction for gamma radiation dosimetry application; Fabricacao e caracterizacao eletrica de heterojuncoes de polianilina - silicio para aplicacao em dosimetria de radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Laranjeira, Jane Maria Goncalves

    2004-08-15

    In this work a technique has been developed to fabricate high quality polyaniline-silicon heterojunction diodes for use as gas and/or ionizing radiation sensors. Polyaniline thin films (40 nm thick) produced by spin-coating on silicon substrates, were the active part of the junction structure. The devices presented excellent reproducibility of their electrical characteristics with high rectification ratio, 60,000 at {+-}1.0 V, and typical reverse current at - 1.0 V of 3 nA at 295 K. A G/I x G plot has been used to analyze the current-voltage characteristics, yielding typical series resistance of 4 k{omega} {+-} 5% and ideality factor in a range of 1,9 {+-} 0.5%. The heterojunction diode presents high sensitivity to gamma radiation in the dose range of 3 x 10{sup -2} to 7 kGy with a linear response in the forward and reverse bias. The excellent electrical characteristics together with the linear response with the dose, strongly suggest the application of this device for spectrometry or dosimetry of high doses of gamma radiation. These devices presented high sensitivity to gas moistures such as ammonia, nitric acid and trichloroethylene. In both cases the sensitivity was observed through shifts of the current-voltage curves, which can be easily monitored to provide a calibration curve of the sensor either as a radiation dosimeter or as a gas sensor for use in applications for gas monitoring or radiation dosimetry. Several aspects of the reliability physics of silicon-polyaniline heterojunction, such as degradation effects induced by local heating, charge trapping and temperature changes, have been discussed. These results further confirm the quality of the devices electrical characteristics and their suitability for radiation and gas sensors applications. Another interesting results presented in this work was the use of polyemeraldine nanofilms (thickness in the range 30-50 nm) deposited by 'spin coating' on glass substrates as an optical dosimeter for gamma radiation based on the color change of the polymer. The nanofilms devices were characterized by UV visible absorption spectroscopy. The deep blue color, characteristic of undoped polyaniline films before irradiation, becomes subsequently green as the film is being irradiated, and the film absorption coefficient exhibits a linear dependence with the logarithm of the irradiation dose from I to 10 kGy. (author)

  13. Application of AmBe source neutron irradiator for determination of inorganic elements in commercial fertilizers; Aplicacao do irradiador de neutrons com fonte de AmBe para determinacao de elementos inorganicos em fertilizantes comerciais

    Energy Technology Data Exchange (ETDEWEB)

    Madi Filho, Tufic; Armelim, Maria Jose Aguirre; Fulas, Paulo Marcelo Marangon [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mail: tmfilho@ipen.br; Trevizam, Anderson Ricardo [Universidade Cruzeiro do Sul (UNICSUL), Sao Paulo, SP (Brazil); Figueira, Rubens Cesar Lopes [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2005-11-15

    The rational use of fertilizers , for the soil fertility correction, contributes to the increase of agricultural production, using the same areas previously available. The quality of products could ne improved with reduced costs. Therefore, knowledge of the chemical characteristics of the correctives used is required to streamline the application and avoid excesses or deficiencies. The studied characteristics are generally limited to the essential nutrients for the nutrition of plants and animals, e.g.: Mn, Zn, P, K, Cu and those known toxic, such as: As, Cd, Hg and Pb. Neutron activation analysis (NAA) is a highly sensitive non destructive technique, for the determination of the elemental composition in samples. It has been particularly useful in the simultaneous determination of inorganic elements in complex samples of several kinds. Several analysis methods for activation are used, such as: comparative and absolute. Commercial fertilizers were analyzed applying the absolute and comparative methods. Using the absolute method, samples were submitted to neutron flux generated by an irradiator with two Am Be sources. The obtained results were compared with those obtained by the comparative method using neutrons generated in the IEA-R1 Reactor. (author)

  14. Application of the neutron irradiator with AmBe sources for inorganic elements in commercial fertilizers determination; Aplicacao do irradiador de neutrons com fontes de AmBe para determinacao de elementos inorganicos em fertilizantes comerciais

    Energy Technology Data Exchange (ETDEWEB)

    Madi Filho, Tufic; Armelin, Maria Jose Aguirre; Fulas, Paulo Marcelo Marangon [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: tmfilho@ipen.br; Figueira, Rubens Cesar Lopes [Universidade Cruzeiro do Sul (UNICSUL), SP (Brazil); Trevizam, Anderson Ricardo [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil)

    2005-07-01

    The rational use of fertilizers, for the soil fertility correction, contributes to the increase of agricultural production, using the same areas previously available. The quality of products could be improved with reduced costs. Therefore, knowledge of the chemical characteristics of the correctives used is required to streamline the application and avoid excesses or deficiencies. The studied characteristics are generally limited to the essential nutrients for the nutrition of plants and animals, e.g.: Mn, Zn, P, K, Cu and those known toxic, such as: As, Cd, Hg and Pb. Neutron activation analysis (NAA) is a highly sensitive non destructive technique, for the determination of the elemental composition in samples. It has been particularly useful in the simultaneous determination of inorganic elements in complex samples of several kinds. Several analysis methods for activation are used, such as: comparative and absolute. Commercial fertilizers were analyzed applying the absolute and comparative methods. Using the absolute method, samples were submitted to neutron flux generated by an Irradiator with two AmBe sources. The obtained results were compared with those obtained by the comparative method using neutrons generated in the IEA-R1 Reactor. (author)

  15. Development of a head phantom to be used for quality control in stereotactic radiosurgery; Desenvolvimento de um simulador de cabeca para a aplicacao no controle da qualidade de radiocirurgia estereotaxica

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Nilseia Aparecida

    2010-05-15

    It was designed and developed a geometric acrylic head phantom (GHP) for Quality Assurance (QA) in Stereotactic Radiosurgery (SRS). Inside the phantom there are inserts that are able to accommodate acrylic targets representing the tumor tissue and organ at risk in the region cranial brain, the brain stem. The tumor tissue is represented by two semi-spheres of acrylic with a diameter of 13.0 mm and cavities in the central region for accommodation of a TLD-100 detector and a small radiochromic EBT Gafchromic filmstrip. The brain stem is represented by the two parts of acrylic cylinder with a diameter 18.0 mm, 38.0 mm length and cavities along the central region to accommodate the 5 detectors TLD-100 and yet another of EBT film. The distance tumor - brain stem is 2.0 mm. The experimental setup was filled with water, attached to the stereotactic frame to determine the coordinates of the target and underwent computed tomography (CT). Cf images were transferred to the SRS planning system BrainLab (BrainScan). The contours of the lesion and organ at risk were delineated and, through the technique of multiple circular arcs, the planning was conduced with five arches, one isocenter and a collimator of 17.5 mm from the combination between the table and gantry . The dose delivered to the isocenter of the lesion was 3.0 Gy and the total coverage of tumor volume corresponds to the 75% isodose. This experimental arrangement is subjected to radiosurgery treatment, after which the dosimeters are evaluated and their responses compared with the values of planned doses. The linear accelerator used was a Varian CLlNAC 2300 CID, photon beam of 6 MV, installed at the National Cancer Institute (INCA). For verification of dose distributions in 3D, the films were irradiated in three planes: sagittal, caronal and axial. The .films were scanned and digitized on a scanner Microtek ScanMaker 9800XL model. The dose distributions in irradiated films were compared with the distributions of doses provided by the planning system through the software PTW VeriSoft gamma index method. The results were obtained with TLD agree with planned dose values within the limits of acceptance. For EBT Gafchromics films, in ali treatment plans, there was agreement between the doses values and isodoses, measured planned, within the tolerance limits for SRS (+- 5% of the administered dose in the isocenter of the lesion and {+-} 1,0 mm spatial deviation), showing that the method used is adequate to ensure the quality of the radiosurgery treatment. (author)

  16. Delphi technique applied to risk identification and assessment on pipe supports fabrication and erection contracts; Aplicacao da tecnica Delphi para identificacao e avaliacao de riscos na contratacao e montagem de suportes de tubulacao

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Rodrigo Luiz Neves; Balbi, Diego Junca de Gonzaga [Promon Engenharia, Sao Paulo, SP (Brazil)

    2012-07-01

    Through the years, Risk Management became an accepted subject in Brazilian Organizations, with its own language, techniques and tools; and its processes are being more and more often introduced in its management models. However, risk identification, assessment and management is a difficult task, and can be even more difficult for construction industry-related projects, for these ventures tend to be more dynamic and complex. In this sense, the objective of this paper is to present the application of Delphi technique for risk identification in the erection of piping support. To achieve the desired objective, a literature review of theory references was conducted to understand concepts involved. To apply the technique itself, experts in plant erection were involving. (author)

  17. Model for equipment life-cycle cost forecasting and its application in assets management in the oil industry; Modelo para previsao de custo de ciclo de vida de equipamentos e sua aplicacao na gestao de ativos na industria do petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Cesca, Igor Gimenes; Elias Junior, Antonio; Carvalho, Marcos Henrique [Universidade Estadual de Campinas (DEP/FEM/UNICAMP), SP (Brazil). Dept. de Engenharia de Petroleo; Lima, Gabriel Alves da Costa [Centro de Estudos de Petroleo (CEPETRO/UNICAMP), SP (Brazil)

    2012-07-01

    In the area of oil exploration and production (E and P), knowing the behavior of the equipment in their life cycles becomes even more important than in other industries due to: 1) high cost and 2) severity in terms of requirements safety. The purchase of equipment should not be decided only at the initial cost, but through the life cycle cost (LCC). This paper presents a study to find the cost over the life cycle of a group of equipment used in the petroleum industry by methods of dynamic programming, as well as a discussion on how to use such information in assets management in order to obtain better financial indicators. The main causes of variation in the useful economic life of equipment is the resale value and maintenance costs. Thus, it is possible to avoid high expenditure on maintenance costs and avoid an excessive depreciation of the equipment. So it is possible to conclude that the more intense the depreciation of value, the greater the useful economic life. For maintenance costs, the more intense are the costs, the lower the useful economic life. (author)

  18. Polymers and composites synthesis and characterization for application on PEM type fuel cells; Sintese e caracterizacao de polimeros e compositos para aplicacao em celulas a combustivel do tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, Raigenis da Paz; Souza, Daniele Ribeiro; Barreto, Ednardo Gomes; Boaventura Filho, Jaime Soares; Jose, Nadia Mamede [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil)]. E-mail: raigenis@gmail.com

    2006-07-01

    The PEM (proton exchanging membrane) type fuel cell presents good potential for the energy production without the residue generation. However, its manufacture presents high costs for commercial application, mainly due to the electrolyte. Sulfonated Peek (polish-ether-ether-ketone) supported or auto immobilized the in a silicone matrix is an interesting alternative as electrolyte for PEM fuel cells. The commercial PEEK in powder form was functionalized with sulfuric acid, giving the SPEEK (Sulfonated PEEK). The membranes were produced by hot pressing the SPEEK immobilized in a silicone matrix produced by the sol-gel process. The membranes obtained were characterized by DRX, FTIR, TGA, MEV, DSC and protonic conductivity measurements. (author)

  19. Application of gamma irradiation for incorporation of rubber powder in the formulations of EPDM and natural rubber; Aplicacao da radiacao gama para incorporacao do po de borracha em formulacoes de borracha natural e EPDM

    Energy Technology Data Exchange (ETDEWEB)

    Kiyan, Ludmila Y.P.; Parra, Duclerc Fernandes; Lugao, Ademar Benevolo, E-mail: ludmilapozzo@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP/CQMA), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente

    2013-07-01

    The objective of this work was to study the behavior of the recycling of rubber burrs in form of powder, of the rubber industry from EPDM rubber powder and natural rubber with SBR. The rubber powder was irradiated and reused in rubber artifacts formulations for classical vulcanization. The processed material was irradiated using a {sup 60}Co source in doses of 50, 100, 150 and 200 kGy and a dose rate of 5 kGy s-1 at room temperature. The radiation created devulcanization active sites for subsequent integration of the material (rubber powder) in formulations of commercial use. The processes were compared and their products characterized by analytical methods of the physical properties such as strength and elongation. Satisfactory results were found, noting a major spin-off of EPDM chain demonstrated by increased elongation.

  20. Comparative analysis of the cost of application for a blade of irrigation using electric energy and diesel; Analise comparativa do custo para aplicacao de uma lamina de irrigacao utilizando energia eletrica e diesel

    Energy Technology Data Exchange (ETDEWEB)

    Sa Junior, Arionaldo; Carvalho, Jacinto de Assuncao; Oliveria, Eduardo Carvalho de [Universidade Federal de Lavras (DEG/UFLA), MG (Brazil). Dept. de Engenharia], email: arionaldojr@hotmail.com

    2011-07-01

    The aim of this study was to estimate the cost of electric and diesel power for the application of 1 mm of irrigation in an area of 1 hectare. The Tariff Group considered was 'B' for low voltage and subgroup 'B2 Rural'. The fares used were obtained from CEMIG, being of R$ 0.22019. The diesel value adopted was the month of November 2010 in the southern region of Minas Gerais, comprising $ 1.97 L{sup -1}. For purposes of calculation, the total income of the height manometric were taken, respectively, 60%, 65%, 70%, 75% and 10, 25, 75, 100, 125, 150, 175 and 200 mca. To calculate the total cost with the application of the depth of 1mm was considered that the cost of energy accounts for 65% and 75% for electric and diesel, respectively. The results show a increase in energy costs by increasing the total head. The use of systems more efficient pump reduces the cost of electric power in the order of 6.7% to 20% and diesel from 3.6% to 16.2% for the proposed situations. In all cases the electric power is more appropriate with regard to cost. The relationship between electricity and diesel is 51.62% and 15.98% for better and worse, respectively. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Clayton Pereira da

    2012-07-01

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

  2. Production of biosurfactants for application in the removal of environmental contaminants generated in the petroleum industry; Producao de biossurfactantes para aplicacao na remocao de contaminantes ambientais gerados na industria do petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Sarubbo, Leonie A.; Rufino, Raquel D.; Luna, Juliana M. de; Farias, Charles B.B.; Santos, Valdemir A. dos [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil)

    2012-07-01

    This paper describes the application of microbial surfactants in removing crude oil and marine environment located in the proximity of the Pernambuco Thermoelectric. Two biosurfactants were produced by yeasts Candida sphaerica and C. lipolytica grown in industrial wastes during 72 and 144 hours, respectively. The surface tensions of the biomolecules (25 mN/m) were determined, the production yields were estimated (8 and 9 g/L) and the CMC determined (0.03%). The biosurfactants were applied to samples of sea water and rocks contaminated with petroleum and motor oil. The results demonstrated the oil dispersant action of the biosurfactant from C. sphaerica and the emulsifying ability of the biosurfactant from C. lipolytica. Percentages removals of 100% of oil and petroleum were obtained for both biosurfactants. The possibility of application of biosurfactants in the remediation of oil polluted environments motivates the advancement of research to develop this alternative technology for effective use in the Termope Thermoelectric treatment systems. (author)

  3. Effect of substitutional element in the microstructure and hardness of Ti-Zr system alloys used as biomaterials; Efeito do elemento substitucional na microestrutura e dureza de ligas do sistema Ti-Zr para aplicacao como biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Correa, D.R.N.; Vicente, F.B.; Grandini, C.R., E-mail: diegornc@fc.unesp.b [Universidade Estadual Paulista (UNESP), Bauru, SP (Brazil). Lab. de Anelasticidade e Biomateriais

    2010-07-01

    New titanium alloys had been developed with the aim of obtaining materials with improved properties for application as biomaterial, and alloys of the Ti-Zr system are among those most promising. The objective of this study is to analyze the influence of the zirconium concentration on microstructure and hardness of the Ti-5Zr, Ti-10Zr and Ti-15Zr alloys. After arc-melting melting, the samples were analyzed by chemical and gas composition, and characterized by density measurements, optical microscopy, x-ray diffraction and hardness. The results showed a microstructure formed by alpha phase (hexagonal close-packed structure) and increased of hardness. (author)

  4. Preparation of gas diffusion layers for PEMFC fuel cells using carbon fibers; Elaboracao de uma camada de difusao de gas a partir de fibras de carbono para aplicacao em celulas combustiveis do tipo PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Santos, J.N.; Kunsti, S.R.; Malfatti, C.F. [Universidade Federal do Rio Grande do Sul - Departamento de Metalurgia (PPGEM) - Laboratorio de Pesquisa em Corrosao (LAPEC), Porto Alegre, RS (Brazil); Vargas, J.V.C. [Universidade Federal do Parana - Departamento de Engenharia Mecanica, PR (Brazil); Amico, S.C. [Universidade Federal do Rio Grande do Sul - Departamento de Materiais, RS (Brazil)

    2010-07-01

    The electrode/membrane system, called MEA, is the fundamental unit of a PEMFC (proton exchange membrane fuel cell). Within the MEA, the gas diffusion layer (GDL) is the bridge between the flow field and the catalyst layer. One of the important elements in a GDL is the substrate, typically a carbon cloth or paper, that has to be an excellent electrical conductor and show mechanical strength along with thermal and chemical stability. In this work, GDLs were produced from a suspension containing short carbon fibers in water-based polyurethane and poly(vinyl alcohol) (PVA) resins with appropriate characteristics to be used in low temperature fuel cells. The obtained GDL was characterized regarding its wettability, electrical conductivity and morphological aspects, evaluated by SEM. (author)

  5. Blends of PHB/PEG: obtention of matrices for use as controlled drug release systems; Obtencao de blendas de PHB/PEG para matrizes de sistemas micro e nanoestruturados visando aplicacao em liberacao controlada de farmacos

    Energy Technology Data Exchange (ETDEWEB)

    Catoni, S.E.M.; Gomes, C.A.T.; Trindade, K.N.S.; Schneider, A.L.S.; Pezzin, A.P.T., E-mail: sara.elisamoreira@hotmail.co [Universidade da Regiao de Joinville (UNIVILLE), SC (Brazil); Soldi, V. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil)

    2010-07-01

    Different materials have been used in the development of micro-and nanostructured systems for drug release. In general, poly(3-hydroxybutyrate) (PHB) matrixes have high crystallinity degree, justifying its slow degradation. This feature makes the attack of enzymes more difficult. Thus, the surface modification with hydrophilic polymers such as poly(ethylene glycol) (PEG) has been investigated in order to obtain particles which are not recognized and captured by phagocytic cells after in vivo administration, staying for a longer in the systemic circulation. In this work, PHB/PEG films were prepared by casting in different proportions and characterized by XRD, DSC, SEM, GPC and TGA. The films presented high crystallinity degree and showed uniformity, except the 50/50 composition which showed the presence of two phases. The results revealed that increasing percentage of PEG, the Tm of PHB was decreased, the thermal stability was dramatically decreased and molecular weight of the samples was lower. (author)

  6. Mechanical and electrical evaluation of a dilute aluminium alloy heat treated for application in electrical cables and wires; Avaliacao mecanica e eletrica de uma liga diluida de aluminio tratada termicamente para aplicacao em fios e cabos eletricos

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, E.S. [Faculdade de Engenharia Mecanica - Unicamp - Campinas, SP (Brazil)], e-mail: manu@fem.unicamp.br; Kamizono, K.A.; Nogueira, P.; Nogueira, A.T.; Quaresma, Jose Maria do Vale [Universidade Federal do Para - UFPA, PA (Brazil)

    2010-07-01

    With the need to investigate new materials developed and presented to the market of non-ferrous materials and in particular those developed for the transmission and distribution of electricity, we conducted a study on a dilute alloy Al-EC-0, 7% Si, where from his previous characterization and thus knowing their good mechanical and electrical properties, we developed a new aluminum alloy in an attempt to know the properties of the alloy Al-EC-0, 7% Si in the presence of alloying elements, titanium. Being the new alloy under different thermal treatment temperature in order to observe their behavior under such mechanical and electrical conditions. (author)

  7. Electrical resistivity of ceramic-metal composite materials in the percolation region: application in crucibles for induction furnaces; Resistividade eletrica de materiais compositos do tipo ceramica-metal na regiao de percolacao: aplicacao em cadinhos para fornos de inducao

    Energy Technology Data Exchange (ETDEWEB)

    Sene, Frank Ferrer

    1997-07-01

    Ceramic composite materials were produced by mixing powders of Partially Stabilized (PSZ) with titanium, niobium or nickel, and cristobalite with titanium. Pellets were produced by uniaxially pressing the material followed by cold isostatic pressing and finally sintering at 1600 deg C for 1,5 hours in argon. The metal content was varied in the range of 0-40 volume percent (v/o). Electrical resistivity measurements were performed in the temperature range of 25 - 700 deg C. Samples containing metallic inclusions above 25 v/o show the predominance of electronic type conducting. For samples with metallic inclusion below 25 v/o, a typically ionic conduction behavior has been observed. PSZ-Ti and PSZ-Ni samples containing 25 v/o of metallic inclusions show an insulator - conductor transition in a given temperature range. Cristobalite samples containing 30 v/o of titanium show a conductor - insulator transition also in a specific temperature range. Tests performed in an induction furnace showed that samples containing metallic inclusions above 25 v/o had self-heated when exposed to electro magnetic fields in the range of radio frequency (r.f.) Crucibles of PSZ-Ti were made by slip casting followed by sintering at 1600 deg C for 1.5 hours in argon. These crucibles were exposed to electromagnetic fields in the r.f. range and the maximum temperature reached was 1350 deg C. Microstructure characterization was performed on those materials by X-ray diffraction, EDS, optical and scanning electron microscopy. (author)

  8. Treatment of post-consumption oils from Paraiba state - Brazil - clays for application as bio fuel; Tratamento de oleos pos-consumo a partir de argilas da Paraiba para aplicacao como biocombustivel

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, E.P.; Oliveira, S.V. de; Medeiros, K.M. de; Silva, D.F. da; Araujo, E.M.; Fook, M.V.L. [Universidade Federal de Campina Grande (DEMa/UFCG), PB (Brazil). Dept. de Engenharia de Materiais], e-mail: elainepatriciaaraujo@yahoo.com.br

    2008-07-01

    The utilization of fuels of agricultural origin in the cycle diesel engines is a good alternative to reduce dependence on importation petroleum, since these fuels are a renewable source of energy. The utilization of biodiesel as biofuel is a contribution to the environment, reducing the qualitative and quantitative form levels of environmental pollution. The recycling of post-consumption oil helps reduce the uncontrolled disposal and environmentally dangerous, than to obtain fuel with a cost / benefit and offering a competitive alternative commercial advantage. However, these oils should go through a process of decontamination and clearing up the stage of chemical conversion which is used clay to lighten the oil. This work had as its objective to make a literature revision evaluating the potential of the clearing clay modified in Paraiba, used in post-consumption oils for application as biofuel. (author)

  9. Assessment of recycled PET properties for application on oil wells as sand control agents; Avaliacao de propriedades de PET reciclado para aplicacao em pocos de petroleo como agente de contencao de areia

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Alexandre Zacarias Ignacio [PETROBRAS, Rio de Janeiro, RJ (Brazil); Delpech, Marcia Cerqueira [Universidade do Estado do Rio de Janeiro (IQ/UERJ), RJ (Brazil). Inst. de Quimica], e-mail: mcd@uerj.br

    2008-07-01

    The Sand Control is fundamental for oil production in unconsolidated sandstone formations. It consists of the installation of a filter made of stainless steel screens and grained materials (sand control agents) which are, normally, high density inorganic substances (sand, ceramic, bauxite). Shallow formations, near to the sea bed, are more sensitive and need different kinds of sand control agents with low density. The objective of this work was the evaluation of recycled poly(ethylene terephthalate), PET, as sand control agent for oil wells. Pack permeability and thermal stability tests results, after up to six months of exposure to sea water and crude oil, have indicated that the recycled PET kept the necessary characteristics for the proposed application. Also, it was observed that the PET grain pack did not presented significant property modifications in the exposure conditions, when compared to the non-exposed samples. (author)

  10. Evaluation of performance of AISI 444 steel for application in distillation towers; Avaliacao do desempenho do aco AISI 444 para aplicacao como 'lining' em torres de destilacao

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, R.F.; Miranda, H.C. de; Farias, J.P. [Universidade Federal do Ceara (DEMM/UFC), Fortaleza, CE (Brazil). Dept. de Engenharia Metalurgica e de Materiais. Lab. de Caracterizacao de Materiais], e-mail: rf.guimaraes@yahoo.com.br

    2008-07-01

    In this work, the behavior of the AISI 444 ferritic stainless steel submitted to thermal fatigue test and their corrosion resistance in heavy crude oil was evaluated. The AWS E309MoL-16 and E316L-17 weld metal was employed as filler metal. Plates of the AISI 444 were welded on ASTM A-516 Gr. 60 plates and submitted to fatigue thermal cycle. Samples were extracted from plates welded and heat treated immersed in heavy crude oil at 300 deg C. Optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive of X-ray analysis (EDX) were used to characterize the microstructure and the corroded surface. The results show that the AISI 444 stainless steels did not present cracks after the thermal fatigue cycle and the heat treated immerse in heavy crude oil. The electrode AWS E309MoL-16 show better corrosion resistance than the AWS E316L-17. (author)

  11. Microstructural characterization of composite cobaltite and lanthanum-based ceria for use as fuel cell cathodes; Caracterizacao microestrutural de compositos a base de cobaltita de lantanio e ceria para aplicacao como catodos de celulas a combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, E.R.T.; Nascimento, R.M.; Miranda, A.C. de; Lima, A.M. de, E-mail: erickssonrtr@gmail.com [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil); Macedo, D.A. [Universidade Federal da Paraiba (UFPB), PB (brazil)

    2016-07-01

    Fuel cells are devices that convert chemical energy into electricity via redox reactions. In this work, the lanthanum cobaltite doped with strontium and iron (La{sub 0,6}Sr{sub 0,4}Co{sub 0,2}Fe{sub 0,8}O{sub 3} - LSCF) a traditional cathodes material of the fuel cell was mixed with an electrolyte material (composite) to the base ceria doped with gadolinia and a eutectic mixture of lithium carbonates and sodium (CGO-NLC). The powders of LSCF and CGO-NLC were obtained by the citrate method and mixed to obtain a composite cathode. Samples obtained by uniaxial pressure between 5 and 10 MPa were sintered at 1100°C and investigated by X-ray diffraction, scanning electron microscopy and micro hardness test. A symmetric cell cathode / electrolyte / cathode, obtained by co-pressing and co-sintering was investigated by electron microscopy. The results indicated that the composite is chemically stable up to the sintering temperature used. The hardness ranged between 51 and 227 HV. (author)

  12. Purification and preparation of bismuth(III) iodide for application as radiation semiconductor detector; Purificacao e preparacao do cristal semicondutor de iodeto de bismuto para aplicacao como detector de radiacao

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz, Caue de Mello

    2016-11-01

    This study describes the experimental procedure of a BiI{sub 3} purification method powder, aiming a future application of these semiconductor crystals as room temperature radiation detector. The Repeated Vertical Bridgman Technique was applied for the purification, based on the melting and nucleation phenomena. An ampoule filled with a maximum of 25% by volume of BiI{sub 3} powder was mounted into the Bridgman furnace and vertically moved at a speed of 2 millimeters per hour, inside the furnace with programmed thermal gradient and temperature profile, at a temperature maximum of 530 deg C. The reduction of the impurities in the BiI{sub 3}, each purification, was analysed by Instrumental Neutron Activation Analysis (INAA), in order to evaluate the efficiency of the purification technique established in this work, for trace metal impurities. It was demonstrated that the Repeated Bridgman is effective to reduce the concentration of many impurities in BiI{sub 3}, such as Ag, As, Br, Cr, K, Mo, Na and Sb. The crystalline structure of the BiI{sub 3} crystal purified twice and third times was similar to the BiI{sub 3} pattern. However, for BiI{sub 3} powder and purified once an intensity contribution of the BiOI was observed in the diffractograms. It is known that semiconductor detectors fabricated from high purity crystal exhibit significant improvement in their performance compared to those produced from low purity crystals. (author)

  13. Challenges for environmental risk assessment application in offshore E and P activities in Brazil; Desafios para a aplicacao de analise de risco ecologico nas atividades de E e P offshore no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Cassia de Oliveira; Chame, Luciana Moreira [DNV Brasil, Rio de Janeiro, RJ (Brazil); Cantarino, Anderson Americo Alves [BP Brasil, SP (Brazil)

    2004-07-01

    Although the Brazilian Legislation does not clearly specify the requirements and the need to elaborate and apply the Environmental Risk Analysis, the Term of Reference to submit studies to Environmental Entities for E and P offshore activities has required the presentation of an {sup E}nvironment Risk Analysis{sup .} Nevertheless, the interactions or possible effects of these accidents as well as possible chronic discharges are not focused. The Environment Risk Analysis programs used world wide for offshore petroleum activities are very sophisticated and need intense research, specially by universities to be adequate and applicable in Brazil. The studies briefly described in this work, when developed may give the characteristics of Brazilian offshore, important information on the potential of the environment impact of the E and P activities, reducing significantly today's subjectivity on evaluation of impacts and environmental risks. (author)

  14. Preparation, characterization and evaluation of electrocatalysts supported on functionalized carbon black for polymer exchange membrane fuel cell applications; Preparacao, caracterizacao e avaliacao de eletrocatalisadores suportados em carbono funcionalizado para aplicacao em celulas a combustivel tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Marcelo do

    2008-12-18

    The fuel cell technology associated with the growing exigency of low environmental impact energy became prosperous in the world energy scenery. The fuel cell is basically a device that converts directly the chemical energy of a fuel into electrical and thermal energy with a continuous operation by the constant feed of a fuel. Especially, the carbon black Vulcan XC72 is usually employed as an electro catalyst support, and some factors as an accessible and high surface area in order to get maximum particles dispersion, pore size, adequate pore distribution and the presence of functional groups in the carbon black surface are considered fundamental characteristics for an innovative materials development. However, the Vulcan XC72 still reveals insufficient conditions for these purposes. This study consists in the preparation and in the physical chemical characterization of functionalized carbon black by hydrogen peroxide and by polymeric chains with proton conduction properties, and its posterior utilization as electro catalyst support for PEMFC and DMFC application. After the carbon functionalization, an improvement in the carbon black dispersion in water media was observed, a beneficial effect for electro catalyst preparation. It was also observed, that the functional groups and the polymeric chains worked as stabilizers in the particle growing, producing much more homogeneous electrocatalysts, exhibiting smaller average particle size. Especially, in the case of polymeric chains functionalization, a decrease in the ohmic drop was observed for this system, attributed to an improvement in the proton transference. (author)

  15. Poly(vinylidene fluoride) modification induced by gamma irradiation for application as ionic polymer-metal composite; Modificacao de poli(fluoreto de vinilideno) induzida por radiacao gama para aplicacao como composito ionomerico de metal-polimero

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Henrique Perez

    2011-07-01

    Gamma-radiation-induced grafting of styrene into poly(vinylidene fluoride) (PVDF) films with 0.125 mm thickness at doses from 1 to 100 kGy in the presence of a styrene/N,N- dimethylformamide (DMF) solution (1:1, v/v) and styrene/toluene (1:1, v/v) at dose rate of 5 kGy h-1 was carried out by simultaneous method under nitrogen atmosphere at room temperature, using gamma rays from a Co-60. After grafting reactions, the polymer was then sulfonated in chlorosulfonic acid/1,2-dichloroethane (2 and 10%) for 3 hours. The films were characterized before and after modification by calculating the degree of grafting (DOG), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). DOG results show that grafting increases with dose, and varies enormously depending on the solvent used, with DOGs about 20 times greater in DMF than in toluene. It was possible to confirm the grafting of styrene by FT-IR due to the appearance of the new characteristic peaks and by the TG and DSC which exhibited changes in the thermal behavior of the grafted/sulfonated material. Sulfonated material was also characterized by ion exchange capacity (IEC) showed that both DOG and sulfonic acid concentration increase IEC values. Results showed that it is possible to obtain materials with ion exchange capacity of possible application as ionic polymer-metal composites. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Clayton Pereira da

    2012-07-01

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

  17. Bases for an environmental liability management system: application to a repository for radioactive waste; Bases para um sistema de gerenciamento de responsabilidades ambientais: aplicacao a um repositorio de rejeitos radioativos

    Energy Technology Data Exchange (ETDEWEB)

    Tostes, Marcelo Mallat

    1999-03-15

    This thesis aims the establishment of conceptual bases for the development of Environmental Liability Management System - instruments designed to provide financial and managerial coverage to financial liabilities arising from activities that impact the environment. The document analyses the theories that link the evolution of economic thought and environment, as a means of establish the necessary framework for the development of up-to-date environmental policy instruments. From these concepts and from the analysis of environmental liability system being implemented in several countries, the bases for environmental liability systems development are drawn. Finally, a study is carried out on the application of these bases for the development of an environmental liability management system for a radioactive waste repository. (author)

  18. Preliminary evaluation of the utilization of biopiles technology to the bioremediation of the soil of Guamare/RN (Brazil); Avaliacao preliminar da aplicacao da tecnologia de biopilhas para a biorremediacao do solo de Guamare/RN (Brasil)

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edmilson P.; Macedo, Gorete R.; Duarte, Marcia M.L. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Engenharia Quimica; Costa, Alex S.S. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2004-07-01

    The aim of this work was to evaluate the use of biopiles to the bioremediation of the soil of Stabilization Station of Guamare-RN-Brazil. The evaluation was performed by the characterization of the soil, tests of biodegradation in laboratory scale and by the use of a complete 2{sup 3} factorial design with triplicate at the central point. The input variables were: Nitrogen concentration; diesel-oil concentration; and inoculum concentration. The response variable was the percentage gravimetric loss of organic matter. Statistical analyses of the main factors and their interactions on the response variable were performed using contour curves and Pareto obtained from the software STATISTICA for Windows, Release 5.5. The results showed that biopiles technology can be used to remediate eventual contaminated areas in that region. (author)

  19. Microstructural development and characterization of lanthanum chromite-based ceramics to application in solid oxide fuel cells; Desenvolvimento microestrutural e caracterizacao de ceramicas a base de cromita de lantanio para aplicacao em celulas a combustivel de oxido solido

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, R.N.; Furtado, J.G. de M.; Soares, C.M.; Serra, E.T. [Centro de Pesquisas de Energia Eletrica (CEPEL), Rio de Janeiro, RJ (Brazil)], e-mail: rnunes@cepel.br

    2006-07-01

    This work has for objective to investigate and to characterize the microstructural development of lanthanum chromite-based ceramics (LaCrO{sub 3}) doped with earth alkaline metals, correlating the microstructural parameters (mainly the densification level) and processing parameters with the electrothermal properties reached. Lanthanum chromite-based ceramic systems doped with earth-alkaline metals (Ca, Mg and Sr) had been produced from respective metallic nitrates by solid state reactions process. The phase compositions were evaluated by X-ray diffraction and the densification level by Archimedes method. The microstructural characterization was effected by scanning electron microscopy, energy dispersive X-ray spectroscopy and thermal analysis techniques. Electrical tests were used to evaluate the electrical conductivity of the studied ceramics. The obtained results corroborate the literature comments concerning the difficulty of lanthanum chromite-based ceramics with high densification level and evidence the great influence of the nature of the dopants on the sintering mechanism and the microstructural and electric characteristics of the produced ceramics. The best ones results, in terms of densification and electrical conductivity, had been gotten through multiple doping with calcium and strontium, and in sintering temperature conditions lower that the normally considered to pure or monodoped lanthanum chromite-based ceramics. (author)

  20. Application of perturbation theory to sensitivity calculations of PWR type reactor cores using the two-channel model; Aplicacao da teoria de perturbacao para calculos de sensibilidade em nucleos de reatores PWR, usando um modelo de dois canais

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, A.C.J.G. de

    1988-12-01

    Sensitivity calculations are very important in design and safety of nuclear reactor cores. Large codes with a great number of physical considerations have been used to perform sensitivity studies. However, these codes need long computation time involving high costs. The perturbation theory has constituted an efficient and economical method to perform sensitivity analysis. The present work is an application of the perturbation theory (matricial formalism) to a simplified model of DNB (Departure from Nucleate Boiling) analysis to perform sensitivity calculations in PWR cores. Expressions to calculate the sensitivity coefficients of enthalpy and coolant velocity with respect to coolant density and hot channel area were developed from the proposed model. The CASNUR.FOR code to evaluate these sensitivity coefficients was written in Fortran. The comparison between results obtained from the matricial formalism of perturbation theory with those obtained directly from the proposed model makes evident the efficiency and potentiality of this perturbation method for nuclear reactor cores sensitivity calculations (author). 23 refs, 4 figs, 7 tabs.

  1. Study for prevention of sucker rods failures though NiCr coating; Estudo para prevencao de falhas de hastes de bombeio de petroleo atraves de aplicacao de revestimento NiCr

    Energy Technology Data Exchange (ETDEWEB)

    Bezerra, Brunno S.L. [PETROBRAS, Rio de Janeiro, RJ (Brazil); Araujo, Paulo M.M. [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil); Figueiredo, Renan T.; Cavalcanti, Eliane B. [Universidade Tiradentes, Aracaju, SE (Brazil)

    2008-07-01

    The use of common materials, as carbon steel, in sucker rods motivated by its low cost, in mature oil wells located on Sergipe, Alagoas, Bahia and Rio Grande do Norte states, which are subjected to tractive-compressive-abrasive like combined loads, added to aggressive environment (oil production in the presence of water, carbon dioxide, hydrogen sulfide, salinity, etc..), leads to the materials drastic degeneration and even its rupture. The substitution of common materials by those which have better resistance o failure is, therefore, limited by high cost. A much cheaper alternative is to modify the surface of common materials used in the subsurface equipment, by applying a protective coating in order to assure the system's performance, durability or better economic viability. In the present work it was studied the use of thermal sprayed NiCr coating in sucker rods. It was studied three thermal spray processes: flame spray, arc spray and HVOF (high velocity oxy fuel). (author)

  2. Preparation and characterization of sulfated zirconia acid catalysts for application in the esterification of cottonseed oil; Preparacao e caracterizacao de catalisadores acidos de zirconia sulfatada para aplicacao na esterificacao do oleo de algodao

    Energy Technology Data Exchange (ETDEWEB)

    Silva, F. N.; Moura, T. F. B.; Silva, A.S.; Costa, A.C.F.M., E-mail: fnilson.s@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Pos-graduacao em Engenharia de Materiais; Pallone, E.M.J.A. [Universidade de Sao Paulo (USP), Pirassununga, SP (Brazil). Dept. de Ciencias Basicas

    2017-07-15

    This work aimed to produce zirconia by combustion synthesis, to analyze the structure and morphology comparatively with a commercial monoclinic ZrO{sub 2} , as well as, to investigate the sulfation, aiming to obtain acid catalysts for its use in the esterification of cotton oil for biodiesel. The samples were characterized by X-ray diffraction, scanning electron microscopy (SEM), specific surface area by BET method, infrared spectroscopy (FTIR), thermal analysis (TG/DrTG/DTA), granulometric distribution, pH and chromatography. The synthesized sample evidenced the formation of the monoclinic phase with traces of the orthorhombic phase, while in the commercial sample only the monoclinic phase was observed. In the sulfation process, traces of the tetragonal phase, typical of sulfated zirconia, were observed with the presence of the monoclinic phase in the two samples. With the impregnation of the sulfate ion on the surface of the samples, an increase in the particle size was observed, as seen in the characterization of BET, granulometric distribution and SEM, which also indicated a homogeneous morphology consisting of fine particles of approximately spherical shape for both samples. The chromatography indicated conversion of 65.5 and 91.8% in methyl esters to the synthesized and commercial SO{sub 4} {sup 2-}/ZrO{sub 2} , respectively. The results indicated that the sulfation increased the acidity, which was evidenced by the decrease in the pH, ranging from 5.12 to 2.65, which contributed significantly to the increase of the conversion, indicating that the SO{sub 4} {sup 2-}/ZrO{sub 2} is a promising catalyst in the esterification. (author)

  3. Polymeric membranes obtained from S-PEEK for application in PEM fuel cells; Caracterizacao de membranas polimericas obtidas a partir dos S-PEEK para aplicacao em celulas combustiveis do tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Barreto, Ednardo G.; Fiuza, Raildo A.; Catao, Ronei S.; Jose, Nadia M.; Boaventura, Jaime S. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica], e-mail: ednardobarreto@yahoo.com.br, e-mail: raildofiuza@gmail.com, e-mail: roneicatao@ig.com.br, e-mail: nadia@ufba.br, e-mail: bventura@ufba.br; Pepe, Yuri [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Fisica

    2007-07-01

    This work had the objective to develop and to characterize S-PEEK membranes (sulfonated poly ether ether ketone) through chemical and electrochemical analyses. Conductivity test in function of the frequency and tension had been carried through; as well as, the open circuit tension of a fuel cell using the S-PEEK as electrolyte. Additional tests included TGA (Thermogravimetric Analysis), water absorption test, DSC (Differential Scanning Calorimetry), as tools to characterize conducting, thermal and mechanical proprieties of polymeric membrane. (author)

  4. Non-isolated DC-AC converter with high voltage gain for autonomous systems of electric power; Conversor CC-CA nao isolado com alto ganho de tensao para aplicacao em sistemas autonomos de energia eletrica

    Energy Technology Data Exchange (ETDEWEB)

    Silveira, George Cajazeiras [Centro Federal de Educacao Tecnologica do Ceara (CEFET/CE), Fortaleza, CE (Brazil); Torrico-Bascope, Rene P. [Universidade Federal do Ceara (PPGEE/UFC), Fortaleza, CE (Brazil). Programa de Pos Graduacao em Engenharia Eletrica; Borges Neto, Manuel Rangel [Centro Federal de Educacao Tecnologica de Petrolina (CEFET-PET), PE (Brazil)

    2008-07-01

    A non-isolated DC-AC converter with high voltage gain with two output sinusoidal voltage - 110 V and 220 V - and frequency 60 Hz for application in autonomous systems of electric power is proposed in this work. This topology consists of a boost converter with high voltage gain, based on three-state switching cell combined with a double half bridge inverter. This configuration type the size and the cost are reduced and the efficiency is gotten better, due to the reduced number of switches. The converters that compose this topology operate with high frequency, reducing the volume of the magnetic materials. can be mention as important characteristics: the voltage stress across the switches of the boost converter are low, due they be naturally clamped by one output filter capacitor, which allows the utilization of switches with lower conduction resistances, and the waveforms of the output voltage of the double half bridge inverter supplies for the load it is sinusoidal and it possesses low harmonic content. (author)

  5. Biosurfactant production for application in soil remediation contaminated by oil: study of the virulence factors; Producao de biosurfactantes para aplicacao em remediacao de solos contaminados por petroleo: estudo dos fatores de virulencia

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Ana Carolina Loureiro Brito; Pereira, Marcos Dias; Freire, Denise Maria Guimaraes [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica; Kronemberger, Frederico de Araujo [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-Graduacao de Engenharia (COPPE)

    2008-07-01

    Biosurfactants are amphipatic molecules produced by microorganisms. The rhamnolipid (RML) is a group of those molecules, most produced by strains of Pseudomonas. In this present work, the effect of superficial aeration on the production of rhamnolipids and virulence factors, from proteins produced by Pseudomonas aeruginosa PA1, isolated from oil extraction wells, was evaluated. Cell growth, glycerol and nitrate consumption, rhamnolipid production, nonspecific proteases, total proteins and elastases where investigated on different flask volume/medium volume relations (Vf/Vm): 1:0,15, 1:0,30, 1:0,50 and 1:0,70. It was observed that better oxygenation leaded to better results on the rhamnolipid production. Two peaks of elastase activity were noted, showing possible presence of two types of elastases that could be dislocated on fermentation time, due to the oxygenation degree. The major production of rhamnolipid was found on the 1:0,50 condition and different non-specific proteases standards were found due to the oxygenation degrees. (author)

  6. Methodology to evaluate the energy associated to the industrial solid wastes: application in a metropolitan region of Campinas, Sao Paulo state, Brazil; Metodologia para avaliacao da energia associada ao residuo solido industrial: aplicacao a regiao metropolitada de Campinas

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Tereza Rosana Orrico [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Curso de Pos-graduacao em Planejamento de Sistemas Energeticos; Teixeira, Egle Novaes [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Civil, Arquitetura e Urbanismo; Silva, Ennio Peres da [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Nucleo Interdisciplinar de Planejamento Energetico. Lab. de Hidrogenio

    2004-07-01

    The aim of this work is to the application of a methodology to evaluate the energy associated to the industrial solid wastes in the metropolitan region of Campinas. The methodological route proposed is: the characterization of the research area and the production/management of the industrial solid wastes; the energetic classification and the qualitative/quantitative research of the energy associated to the industrial solid wastes; and, the valuation of the applicability of the energetic utilization mechanisms proposed to the region. This methodology when applied at the Campinas metropolitan region proved to be valid and it resulted in a synthetically presentation of the social and environmental reality of the industrial sector and the destination of the wastes, as well as it indicated the potentialities related to the energetic utilization of the industrial solid waste in the region. With the obtained results it was shown the importance of the the production and the destination of the industrial solid wastes in the Campinas metropolitan region , and the meaning, in terms of electric potency, of the values of the energy associated to the wastes with a known factor of energetic conversion shown in the researched sample. (author)

  7. Scaffold of chitosan/poly(vinyl alcohol) blend chemically crosslinked by glutaraldehyde for tissue engineering applications;Constructos de blendas de quitosana/poli(alcool vinilico) reticulados quimicamente com glutaraldeido para aplicacao em engenharia de tecido

    Energy Technology Data Exchange (ETDEWEB)

    Costa Junior, Ezequiel de S., E-mail: escjr50@deii.cefetmg.b [Centro Federal de Educacao Tecnologica (DEM/CEFET/MG), Belo Horizonte, MG (Brazil). Dept. de Engenharia de Materiais; Laguardia-Nascimento, Mateus; Barbosa-Stancioli, Edel F. [Universidade Federal de Minas Gerais (ICB/UFMG), Belo Horizonte (Brazil). Inst. de Ciencias Biologicas. Dept. de Microbiologia; Mansur, Herman S., E-mail: hmansur@demet.ufmg.b [Universidade Federal de Minas Gerais (DEM/UFMG), Belo Horizonte (Brazil). Dept. de Engenharia Metalurgica

    2009-07-01

    Chitosan/PVA based films were chemically crosslinked by glutaraldehyde (GA) in order to achieve scaffolds for potential tissue engineering application. Both precursors and developed films were characterized by FTIR and XRD in order to determine the presence of chemicals groups and nanostructural order, respectively. The results have showed that the GA crosslinking have altered the crystallinity of the chitosan and the increase on the C=N bands and decreasing of NH{sub 2} bands suggest that Chitosan/GA crosslinking has preference to occur in the carbon 2 by Schiff's base. The mechanical properties, swelling behavior, degradation rate in vitro and cellular viability were compatible with the characteristic of an epithelial tissue. The material presented a toughness range from 1.4 to 34MJ/m3, swelling from 150% to 700% in 24h, degradation rate from 20% to 75% (wt%) in 24h and cellular viability in vitro above 60% compared to the cellular control. The developed scaffolds from the films have also showed swelling and degradation in vitro properties well-matched for biomedical applications in tissue engineering (author)

  8. Wholesale water market application for assured energy certificates allocation among hydroelectric power plants; Aplicacao de um mercado atacadista de agua para reparticao dos certificados de energia assegurada entre usinas hidreletricas

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Andre Dias

    2007-09-15

    The objective of this dissertation is to revise the methodology used in the calculation of assured energy certificates for hydro plants, in particular the relation among the objectives of reliability and market mechanisms with the certificates. The relationship between the economic signals provided by the market 'spot' of electricity with the certificates will be analyzed. It will be shown that the spot price payment does not provide the correct and necessary incentives for the energy certificates allocation in a cascade with agents belonging the different companies. Upstream reservoirs are not property compensated for the regulation of the energy production of the entire cascade and, as solution, alternative scheme to remunerate the water resources (wholesale water market) will be discussed. The assured energy certificates will be calculated with the proposed methodology and compared with nowadays practiced in the Brazilian system. (author)

  9. Application of an aerobic fixed bed bioreactor for treatment of petroleum refinery wastewaters; Aplicacao de um bio-reator aerobio de leito fixo para tratamento de efluentes do refino de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Vendramel, Simone M.; Dezzotti, Marcia; Sant' Anna Junior, Geraldo L. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Programa de Engenharia Quimica

    2004-07-01

    The motivation of this work was to investigate a biological treatment system, which requires low installation area and presents high flexibility. Thus, a laboratory scale aerated submerged fixed-film bioreactor was applied to the treatment of a petroleum refinery wastewater and its performance was monitored. The reactor was continuously operated during 260 days and submitted to different organic loadings in the range of 0.5 to 2.4 kgCOD.m{sup -3}.d{sup -1}. The following removal efficiencies were attained: COD (75 - 91%), TSS and TVS (60 - 92%) and DOC (56 - 91%) and turbidity (71 - 95%). The reactor presented a high level of mixing and showed to be stable when submitted to different hydraulic and organic loadings. Loss of biofilm was negligible and medium clogging problems were not observed. The support medium (PVC plates) showed to be very adequate for microbial adhesion and growth, resulting in stable bioreactor operation. (author)

  10. A study of digital hardware architectures for nuclear reactors protection systems applications - reliability and safety analysis methods; Um estudo de arquiteturas de hardware para aplicacao em sistemas digitais de protecao de reatores nucleares - metodos de analise de confiabilidade e seguranca

    Energy Technology Data Exchange (ETDEWEB)

    Benko, Pedro Luiz

    1997-07-01

    A study of digital hardware architectures, including experience in many countries, topologies and solutions to interface circuits for protection systems of nuclear reactors is presented. Methods for developing digital systems architectures based on fault tolerant and safety requirements is proposed. Directives for assessing such conditions are suggested. Techniques and the most common tools employed in reliability, safety evaluation and modeling of hardware architectures is also presented. Markov chain modeling is used to evaluate the reliability of redundant architectures. In order to estimate software quality, several mechanisms to be used in design, specification, and validation and verification (V and V) procedures are suggested. A digital protection system architecture has been analyzed as a case study. (author)

  11. Optical fibre-lightning arrester cable appliances. Its repercussion in concrete unconventional power transmission lines projects; Aplicacao de cabo para-raios composto com fibra optica. Sua repercursao em projetos de LT`s concreto nao convencionais

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, Ramon Sade [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil)

    1993-12-31

    With the adoption of lightning rod cables made of Optical Fibre, (in systems over Europe, Japan and North America), these became very popular in Countries capable of installing the system. The Brazilian electrical party was then challenged by a new technological experience: the lightning rod cable for lines of transmission has specific characteristics. The particularity of the electrical system in Brazil in relation to the diversity of the parameters involved, and the necessity to clarifying the concepts, take us to new strategies in planning and measuring our Power Transmission Lines 4 refs., 1 tab.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-01-15

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

  13. Obtenção e utilização de microesferas de parafina para confecção de arcabouços teciduais baseados em cimento de α-fosfato tricálcico Production and use of paraffin microspheres for tissue scaffolds based on α-tricalcium phosphate cement

    Directory of Open Access Journals (Sweden)

    J. L. de M. Machado

    2009-06-01

    Full Text Available Um dos fatores mais importantes na técnica conhecida por engenharia de tecidos é o crescimento de células em suporte porosos tridimensionais conhecidos por arcabouços. Os arcabouços guiam o crescimento celular e facilitam a formação de tecidos e órgãos funcionais. Cimentos ósseos são materiais desenvolvidos há aproximadamente uma década para aplicações biomédicas. Um cimento deste tipo pode ser preparado misturando um sal de fosfato de cálcio com uma solução aquosa para que se forme uma pasta que possa reagir à temperatura corporal dando lugar a um precipitado que contenha hidroxiapatita. O desenvolvimento de estruturas porosas de cimento de fosfato de cálcio é de grande utilização em engenharia de tecidos, além de outras áreas da traumatologia. O objetivo deste trabalho foi o uso de cimento de α-TCP (α-fosfato tricálcico para obtenção desses arcabouços, através da obtenção e utilização de esferas de parafina como corpos geradores de poros. O α-TCP foi sintetizado por resfriamento brusco de seus precursores e, as esferas foram produzidas por suspensão em uma solução aquosa de poli (álcool vinílico e sulfato de sódio. As quantidades de cada um destes reagentes foram estudadas com relação ao tamanho das esferas formadas. Pela análise de difração de raios X foi detectada a presença de β-TCP como fase indesejada no processo de síntese do α-TCP e de hidroxiapatita deficiente em cálcio após a reação de pega do cimento. Foi analisada a extração da parafina dos arcabouços por utilização de um método térmico. A porosidade dos arcabouços confeccionados com esferas de parafina foi observada por microscopia eletrônica de varredura, mostrando tamanho, forma e interconectividade dos corpos porosos, que se mostrou adequada para o crescimento celular.One of the most important factors in tissue engineering is the three-dimensional cells growth in porous support known by scaffolds. The scaffolds

  14. Estrategias para negociaciones exitosas.

    OpenAIRE

    José B. Parra V; Evelinda Santiago J.; Misael Murillo M.; Candy Atonal N.

    2010-01-01

    Las estrategias de negociación son herramientas para disminuir conflictos o para intercambiar bienes y servicios. Una negociación exitosa crea relaciones de solidaridad y propicia reciprocidad, cooperación y confianza para quienes tendrán relaciones permanentes de negociación con beneficios para ambas partes. Una estrategia de negociación exitosa requiere manejar el desarrollo del ambiente social del grupo de personas, con la finalidad de tener presente las fronteras que no pueden irrumpirse....

  15. Subvenciones para instituciones Directrices para gastos de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    IDRC CRDI

    División de Administración de Subvenciones ... En la Parte 2 del Acuerdo de Subvención estándar de IDRC se incluyen los límites ... pagar los costos de sustitución (tiempo libre para personal académico) de los investigadores principales.

  16. Synthesis and characterization of nanostructured powders of hydroxyapatite and of three-calcium {beta} phosphate: elaboration of two phase compositions for application in the orthopedics and traumatology; Sintese e caracterizacao de pos nanoestruturados de hidroxiapatita e de fosfato tricalcico {beta}: elaboracao de composicoes bifasicas para aplicacoes na ortopedia e traumatologia

    Energy Technology Data Exchange (ETDEWEB)

    Dalmonico, G.M.L.; Pinheiro, D.M.; Camargo, N.H.A.; Orzechowki, L.G.; Goncalves, A.F.; Melnik, V.; Jesus, J.; Gemelli, E. [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Centro de Ciencias Tecnologicas], e-mail: gidalmonico@gmail.com

    2010-07-01

    This paper synthesized nano structured hydroxyapatite and three calcium {beta} phosphate, for elaboration of two phase compositions of HA/TCP in the concentration in volume of 80% HA/20% TCP-{beta}, 60% HA/40% TCP-{beta} and 50% HA/50% TCP-{beta}. For phase mixing realization, the method of mechanical fragmentation by attritor mill were used. The material recovered from the process of mechanical fragmentation was dried in rotate evaporator, supplying the two phase compositions. The preliminary studies shown the obtention of nano metric powders and a good phase dispersions inside the two phase compositions. (author)

  17. Affinity of hydroxyapatite by radionuclides parent/child in {sup 188}Re/{sup 188}W generator for radiotherapy; Afinidad de la hidroxiapatita por los radionuclidos padre/hijo en el generador {sup 188}Re/{sup 188}W para radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Carrera D, A. A. [Universidad Autonoma de Zacatecas, Unidad Academica de Ciencias Quimicas, Campus Universitario Siglo XXI, Ejido La Escondida, Carretera a Guadalajara Km. 6 (Mexico); Badillo A, V. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela 98068, Zacatecas (Mexico); Badillo A, V. E.; Monroy G, F. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)], e-mail: ana_carrera7@hotmail.com

    2009-10-15

    To assess the feasibility of using apatites as matrices of {sup 188}W/{sup 188}Re generator is essential to obtain the distribution coefficients as much of parent radionuclide as child radionuclide in apatite, that is to say to know their affinity for the solid. It was selected the mineral species more representative as adsorbent, the hydroxyapatite Ca{sub 10} (PO{sub 4}){sub 6}(OH){sub 2} it is known for its great capacity of ions retention and by presenting a large affinity for anionic species in their surface. In this paper we use a synthetic hydroxyapatite marketed by Bio-Rad. This paper presents the preliminary results regarding the affinity of hydroxyapatite for the anionic species tungstates (WO{sub 4}{sup 2-}) and perrhenates (ReO{sub 4}{sup -} in EDTA, as background electrolyte expressed as distribution coefficients between two immiscible phases obtained with the help of radioactive tracers {sup 187}W and {sup 188}Re respectively. The retention measures of these ions, traces show that Bio-Gel hydroxyapatite presents moderate values of distribution coefficients for anionic species of W(Vi) in EDTA 0.01 mol/L that are in the range p H 5 to 6.5; the parent radionuclide of generator {sup 188}Re/{sup 188}W is fixed but not enough to consider it a good absorbent. By contrast, the fixation of perrhenate ions is virtually wiped as may be easily removed from a hydroxyapatite column packed with a saline solution. The influence of this saline solution in the removal of perrhenate ions is null practically. (Author)

  18. Oro para Colombia

    OpenAIRE

    Rubio Forero, María Claudia

    2016-01-01

    Las mujeres han debido atravesar un largo camino partiendo de la discriminación hasta empezar un proceso de equidad en la sociedad y en el deporte, de esta manera llegar a ser parte de un evento como los Juegos Olímpicos. Esta tesis toma el caso de tres atletas colombianas y describe su proceso de formación para lograr dos medallas de oro para el país.

  19. Estrategias para negociaciones exitosas.

    Directory of Open Access Journals (Sweden)

    José B. Parra V

    2010-01-01

    Full Text Available Las estrategias de negociación son herramientas para disminuir conflictos o para intercambiar bienes y servicios. Una negociación exitosa crea relaciones de solidaridad y propicia reciprocidad, cooperación y confianza para quienes tendrán relaciones permanentes de negociación con beneficios para ambas partes. Una estrategia de negociación exitosa requiere manejar el desarrollo del ambiente social del grupo de personas, con la finalidad de tener presente las fronteras que no pueden irrumpirse. Otro aspecto importante, es el lenguaje corporal utilizado por las personas y las tácticas que se practican. El manejo de esta información permite diseñar diferentes modelos de negociaciones para cada caso específico. Este documento propone la utilización de la herramienta MONACO, diseñada por los autores, que es un software útil para encontrar los mejores tácticas posibles dentro de una negociación; basándose en el lenguaje corporal que muestra el negociante oponente durante cada oferta monetaria. El uso de este software da al negociador la oportunidad de manejar las negociaciones con mayor control, el negociador que usa el software puede elegir una estrategia de acuerdo a las relaciones que espera mantener con el negociador oponente.

  20. Antimicrobial activity of different hydroxyapatites; Atividade antimicrobiana de diferentes hidroxiapatitas

    Energy Technology Data Exchange (ETDEWEB)

    Feitosa, G.T.; Santos, M.V.B.; Barreto, H.M.; Osorio, L.R.; Osajima, J.A.; Silva Filho, E.C. da, E-mail: edsonfilho@ufpi.edu.br [Universidade Federal do Piaui (LIMAV/CCN/UFPI), Teresina, PI (Brazil). Centro de Ciencias da Natureza. Laboratorio Interdisciplinar de Materiais Avancados

    2014-07-01

    Among the applications of ceramics in the technological context, hydroxyapatite (HAp) stands out in the scientific community due to chemical biocompatibility and molecular similarity to the structures of bone and dental tissues. Such features are added to the antimicrobial properties that this brings. This work aimed at the synthesis of hydroxyapatite by two different routes, hydrothermal (HD HAp) and co-precipitation (CP HAp), as well as verification of the antimicrobial properties of these through direct contact of the powders synthesized tests with Staphylococcus aureus (SA10) and Escherichia coli (EC7) bacteria. The materials was characterized by XRD, Raman and TEM, and Antimicrobial tests showed inhibitory efficacy of 97% and 9.5% of CP HAp for SA10 and EC7, respectively. The HD HAp had inhibitory effect of 95% and 0% for EC7 and SA10, respectively. The inhibitory effect on SA10 is based on the hydrophilicity that the material possesses. (author)

  1. Separation of lanthanides through hydroxyapatite; Separacion de lantanidos mediante hidroxiapatita

    Energy Technology Data Exchange (ETDEWEB)

    Garcia M, F.G

    2006-07-01

    With the objective of obtaining from an independent way to each one of the lanthanides {sup 151} Pm, {sup 161} Tb, {sup 166} Ho and {sup 177} Lu free of carrier and with high specific activities starting from the indirect irradiation via, it intends in this work to determine the viability of separation of the couples Nd/Pm, Dy/Ho, Gd/Tb and Yb/Lu, by means of ion exchange column chromatography, using hydroxyapatite (HAp) and fluorite like absorbent material in complexing media. It is important to mention that have registered separation studies among lanthanides of the heavy group with those of the slight group, using the same mass and, in comparison with this work, quantities different from the father were used and of the son, also, that the separation studies were carried out among neighboring lanthanides. In this investigation, it was determined the effect that its have the complexing media: KSCN, sodium tartrate, sodium citrate, EDTA and aluminon, their pH and concentration, in the adsorption of the lanthanides in both minerals, in order to determine the chromatographic conditions for separation of the couples Nd/Pm, Dy/Ho, Gd/Tb and Yb/Lu. The work consists of five chapters, in the first one they are presented a theoretical introduction of the characteristics more important of the lanthanides, the hydroxyapatite and the fluorite; in the second, it is deepened in the ion exchange, as well as the two techniques (XRD and High Vacuum Electron Microscopy) to make the characterization of LnCI{sub 3} (Ln = Nd, Gd, Dy or Yb) synthesized. The third chapter, it describes the methodology continued in our experimental work; in the room, its are presented the obtained results of the static and dynamic method to determine the viability of separation of neighboring lanthanides; and finally, the five chapter shows the conclusions. In this study, it is concludes that the separation among neighboring lanthanides cannot be carried out in the minerals and used media; because practically these lanthanides present very similar distribution coefficients in hydroxyapatite; while in the fluorite, they are not retained in any studied media. (Author)

  2. Hydroxyapatite and its applications; Hidroxiapatita y sus aplicaciones

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez T, R.; Palma C, R.; Pina B, M.C. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-360, 04510 Mexico D.F. (Mexico)

    1999-11-01

    In this paper is compared the structure and composition of the femur head from different mammals: human, pork, cow and dog, such as Coraline {sup TM}, in order to find the best material that could be employed an an osteoinductor material. (Author)

  3. Whiskers and fibers of hydroxyapatite; Whiskers e fibras de hidroxiapatita

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, G.B.C.; Motisuke, M.; Zavaglia, C.A.C., E-mail: guicardoso@fem.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Materiais; Arruda, A.C.F. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica. Dept. de Engenharia de Petroleo

    2009-07-01

    Hydroxyapatite is a bioactive ceramic, which acts in tissue engineering by attracting bone cells. Occasionally it can be used as a biocompatible reinforcement. The mechanical role of this biomaterial can be defined depending of some characteristics analyzed by scanning electron microscope and X ray power diffraction. It can be classified in whiskers and fibers; each one has their own properties, which were discussed in this work. For its use as reinforcement it is necessary matrix with specific characteristics. (author)

  4. Tiempo para un cambio

    Science.gov (United States)

    Woltjer, L.

    1987-06-01

    En la reunion celebrada en diciembre dei ano pasado informe al Consejo de mi deseo de terminar mi contrato como Director General de la ESO una vez que fuera aprobado el proyecto dei VLT, que se espera sucedera hacia fines de este aAo. Cuando fue renovada mi designacion hace tres aAos, el Consejo conocia mi intencion de no completar los cinco aAos dei contrato debido a mi deseo de disponer de mas tiempo para otras actividades. Ahora, una vez terminada la fase preparatoria para el VLT, Y habiendose presentado el proyecto formalmente al Consejo el dia 31 de marzo, y esperando su muy probable aprobacion antes dei termino de este ano, me parece que el 10 de enero de 1988 presenta una excelente fecha para que se produzca un cambio en la administracion de la ESO.

  5. Para-Hermitian and para-quaternionic manifolds

    International Nuclear Information System (INIS)

    Ivanov, S.; Zamkovoy, S.

    2003-10-01

    A set of canonical para-Hermitian connections on an almost para-Hermitian manifold is defined. A Para-hermitian version of the Apostolov-Gauduchon generalization of the Goldberg-Sachs theorem in General Relativity is given. It is proved that the Nijenhuis tensor of a Nearly para-Kaehler manifolds is parallel with respect to the canonical connection. Salamon's twistor construction on quaternionic manifold is adapted to the para-quaternionic case. A locally conformally hyper-para-Kaehler (hypersymplectic) flat structure with parallel Lee form on the Kodaira-Thurston complex surfaces modeled on S 1 x SL (2, R)-tilde is constructed. Anti-self-dual locally conformally hyper-para-Kaehler (hypersymplectic) neutral metrics with non vanishing Weyl tensor are obtained on the Inoe surfaces. An example of anti-self-dual neutral metric which is not locally conformally hyper-para-Kaehler (hypersymplectic) is constructed. (author)

  6. Para-Hermitian and para-quaternionic manifolds

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, S [University of Sofia ' St. Kl. Ohridski' , Faculty of Mathematics and Informatics, Sofia (Bulgaria) and Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Zamkovoy, S [University of Sofia ' St. Kl. Ohridski' , Faculty of Mathematics and Informatics, Sofia (Bulgaria)

    2003-10-01

    A set of canonical para-Hermitian connections on an almost para-Hermitian manifold is defined. A Para-hermitian version of the Apostolov-Gauduchon generalization of the Goldberg-Sachs theorem in General Relativity is given. It is proved that the Nijenhuis tensor of a Nearly para-Kaehler manifolds is parallel with respect to the canonical connection. Salamon's twistor construction on quaternionic manifold is adapted to the para-quaternionic case. A locally conformally hyper-para-Kaehler (hypersymplectic) flat structure with parallel Lee form on the Kodaira-Thurston complex surfaces modeled on S{sup 1} x SL (2, R)-tilde is constructed. Anti-self-dual locally conformally hyper-para-Kaehler (hypersymplectic) neutral metrics with non vanishing Weyl tensor are obtained on the Inoe surfaces. An example of anti-self-dual neutral metric which is not locally conformally hyper-para-Kaehler (hypersymplectic) is constructed. (author)

  7. ParaChoice Model.

    Energy Technology Data Exchange (ETDEWEB)

    Heimer, Brandon Walter [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Levinson, Rebecca Sobel [Sandia National Lab. (SNL-CA), Livermore, CA (United States); West, Todd H. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2017-12-01

    Analysis with the ParaChoice model addresses three barriers from the VTO Multi-Year Program Plan: availability of alternative fuels and electric charging station infrastructure, availability of AFVs and electric drive vehicles, and consumer reluctance to purchase new technologies. In this fiscal year, we first examined the relationship between the availability of alternative fuels and station infrastructure. Specifically, we studied how electric vehicle charging infrastructure affects the ability of EVs to compete with vehicles that rely on mature, conventional petroleum-based fuels. Second, we studied how the availability of less costly AFVs promotes their representation in the LDV fleet. Third, we used ParaChoice trade space analyses to help inform which consumers are reluctant to purchase new technologies. Last, we began analysis of impacts of alternative energy technologies on Class 8 trucks to isolate those that may most efficaciously advance HDV efficiency and petroleum use reduction goals.

  8. Universidades accesibles para todos

    Directory of Open Access Journals (Sweden)

    Roxana Stupp Kupiec

    2001-01-01

    Full Text Available Este trabajo pretende hacer conciencia sobrelos factores que inciden en la construcción colectiva deuniversidades dispuestas a innovar y transformar suideología, sus políticas, el currículum, los servicios estu-diantiles, la infraestructura física y administrativa y lasestrategias de comunicación e información, bajo el para-digma de la accesibilidad en el entorno. Se hace referen-cia al marco legal internacional y nacional que orientalas acciones que deben planificarse e implementarse enlas instituciones de Educación Superior.En la construcción de universidades accesibles para to-dos se requiere de un cambio en la concepción curricu-lar. Se analizan conceptos como la flexibilidad en la for-mación y el acceso a los planes de estudio para respondera las necesidades educativas de todos los estudiantes. Para promover estas transformaciones se proponen prin-cipios y prácticas tales como la interdisciplinareidad y lainclusión del tema de la discapacidad en todas las carre-ras. Además, se presentan ejemplos de aplicación en dife-rentes áreas del perfil profesional, en la formación deldocente universitario y en actividades de proyección so-cial, vida estudiantil e investigación. En el ámbito estu-diantil, se describen algunos servicios y procesos que sehan desarrollado en la Universidad de Costa Rica

  9. Educando para la ignorancia

    Directory of Open Access Journals (Sweden)

    Miguel Durán

    1996-06-01

    Full Text Available Más que describir una situación particular, los autores buscan con este escrito motivar al estudiante para que asuma posiciones críticas; así como dar un campanazo de alerta a los profesores, en relación a los conocimientos que transmiten a sus alumnos y la forma en que lo hacen; todo con el ánimo de generar verdaderos espacios de reflexión en la universidad.

  10. INICIATIVAS PARA EL CAMBIO

    Directory of Open Access Journals (Sweden)

    César Alfonso Defrancisco-Larrañaga

    2013-07-01

    Full Text Available El planeta no atraviesa por su mejor momento en materia de conservación y renovación de sus recursos naturales. Claramente en los últimos tiempos los recursos hídricos han venido haciéndose cada vez menores; el hombre ha notado con preocupación y vivido en carne propia este fenómeno, que de no ser tratado a tiempo, podría atentar contra la existencia misma. Esto lo ha alentado a buscar métodos que sirvan como solución para contrarrestar éste mal y crear conciencia entre sus iguales, para así poder garantizar su permanencia y la de su entorno durante muchas generaciones. En países desarrollados del continente europeo y en algunos lugares de América del norte, el uso de sistemas de reutilización y tratamiento de aguas grises y aprovechamiento de las aguas lluvias se ha convertido en una constante y nos están dando las pautas para poder seguir el ejemplo y así de esta manera poder aportar a la causa ambiental y a su vez crear un ahorro en nuestros gastos mensuales de consumo.

  11. para mejorar el %R

    Directory of Open Access Journals (Sweden)

    Alfredo Díaz Mata

    2001-01-01

    Full Text Available En este trabajo se revisan dos indicadores técnicos bursátiles que están estrechamente relacionados, el oscilador estocástico %K de Lane y el oscilador %R de Williams; asimismo, se evalúa el uso de dos mecanismos asociados con el primero y que no suelen utilizarse con el %R: el proceso de frenado (slowing y el uso de un promedio móvil del propio oscilador estocástico como disparadores de señales de compra y de venta. Realizando simulaciones con 27 acciones y el Índice de Precios y Cotizaciones de la Bolsa Mexicana de Valores se verifica la hipótesis principal y se comprueba que, efectivamente, en muchos casos, el uso del proceso de frenado con el oscilador %R de Williams permite tomar mejores decisiones. Por otro lado, se concluye que de los dos disparadores de señales el que mejor funciona, tanto para %K como para %R es el uso de cotas inferior y superior. Este artículo surgió en el curso de una investigación sobre el análisis técnico bursátil de acciones que se puede realizar en su totalidad por computadora y que, esencialmente, excluye el análisis gráfico. Uno de los propósitos del estudio es determinar si es posible, y bajo qué mecanismos, establecer un sistema de análisis bursátil que le permita al inversionista tomar decisiones de inversión en acciones en la Bolsa Mexicana de Valores sin tener que emplear la considerable cantidad de tiempo que es necesario para el análisis gráfico tradicional. Durante este estudio se realizó un análisis preliminar de unos 120 indicadores técnicos para, por un lado, conocerlos con cierto detalle y, por otra parte, aislar aquellos que prometían ser de utilidad para el objetivo de la investigación. Fue en este proceso cuando se detectó que existen dos indicadores que están relacionados y que permiten un análisis por separado que tiene, cuando menos, dos ventajas. En primer lugar está el placer que da a quien gusta de estos temas encontrarse con indicadores que, de acuerdo

  12. Inmunopotenciadores para la acuicultura

    Directory of Open Access Journals (Sweden)

    Rocmira Pérez

    2014-04-01

    Full Text Available La acuicultura es una de las actividades económicas de mayor crecimiento para la producción de alimentos. Uno de sus principales retos es la obtención de grandes volúmenes de producción con la mayor calidad posible. Esto conlleva a una reducción de la aplicación de antibióticos y productos quimioterapéuticos. Una de las estrategias más prometedoras es la aplicación de inmunopotenciadores, principalmente en los cultivos intensivos. El objetivo de este trabajo fue revisar los principales inmunopotenciadores, así como las tendencias y retos de su uso mundial. Se resumen las particularidades moleculares y funcionales de los mismos y se hace énfasis en los más estudiados: levamisol, ß-glucanos, lipopolisacárido, vitamina C, extractos de plantas y hormonas. Todos estos compuestos de naturaleza heterogénea inciden mayoritariamente en los componentes de la inmunidad innata de los peces, fortaleciendo y potenciando la resistencia a enfermedades; adicionalmente algunos de ellos tienen funciones antiestrés y favorecen su crecimiento. Se concluye que los inmunopotenciadores constituyen una estrategia viable para reducir las pérdidas por problemas sanitarios en el sector de la acuicultura; pero aún quedan por solucionar aspectos como la vía de administración y la etapa de inmunización adecuada para cada especie y tipo de cultivo.

  13. Ha vuelto para mirarnos

    OpenAIRE

    Casalderrey, Francisco

    2008-01-01

    En cada entrega analizaremos un cuadro, mirándolo con ojos matemáticos. Con esa particular mirada, fruto de nuestra propia (de)formación. Y desde ese punto de vista haremos paseos por el arte y las matemáticas. Espero que el lector, como hago yo mismo, disfrute descubriendo más allá de lo que a simple vista distinguiría cualquiera. Al fin de cuentas, el arte, como las matemáticas, han sido creados para hacernos disfrutar.

  14. Interfaces para control cerebral

    OpenAIRE

    Spinelli, Enrique Mario

    2000-01-01

    La función de una interfaz para control cerebral basada en señales de electroencefalograma (EEG), en forma general denominada BCI (Brain control Interface), es establecer un enlace directo entre el cerebro y una máquina, sin utilizar acciones motoras directas. Una BCI permite realizar operaciones simples a partir de la interpretación de las señales de EEG. Su desarrollo está principalmente orientado hacia la ayuda a personas con discapacidades motoras severas, que poseen deterioros en el sist...

  15. Comunicar para la salud

    Directory of Open Access Journals (Sweden)

    Lic. Eva Bocco

    1998-01-01

    Full Text Available Con este trabajo quiero plantearles una inquietud en torno al rol que nos cabe a los comunicadores en el área de la salud desde la perspectiva de la comunicación para la salud. ¿Se puede pensar la salud pública desvinculada de la comunicación? ¿La comunicación es posible sin la existencia de salud en la comunidad? ¿Qué puede hacer un comunicador en el ministerio de salud? ¿Puede un estado desarrollar políticas de salud sin la presencia de la comunicación?

  16. Democracia para ciudadanos ciborgs

    Directory of Open Access Journals (Sweden)

    Juan Varela

    2007-07-01

    Full Text Available Enumera los instrumentos imprescindibles de la ciberpolítica para campañas electorales en España, cuando se renovaron los cargos municipales. La política vuelve a ser personal cuando ciudadanos y políticos se hablan cara a cara y cita varios ejemplos, reconociendo la recuperación de la comunicación directa. La ciberdemocracia es muy exigente. Los políticos prefieren la magia de la imagen. La sociedad no sabe como detener la propaganda viral que bombardea a los buscadores de red.

  17. Democracia para ciudadanos ciborgs

    OpenAIRE

    Juan Varela

    2007-01-01

    Enumera los instrumentos imprescindibles de la ciberpolítica para campañas electorales en España, cuando se renovaron los cargos municipales. La política vuelve a ser personal cuando ciudadanos y políticos se hablan cara a cara y cita varios ejemplos, reconociendo la recuperación de la comunicación directa. La ciberdemocracia es muy exigente. Los políticos prefieren la magia de la imagen. La sociedad no sabe como detener la propaganda viral que bombardea a los buscadores de red.

  18. Disruptive tension under normalized atmospheric pulse and residual tension on lightning arresters power systems: statistical methods application. Practical results and comments; Ensaios de tensao disruptiva sob impulso atmosferico normalizado e tensao residual em para-raios para sistemas de potencia: a aplicacao de metodos estatisticos. Comentarios e resultados praticos

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, M.L.B. [ELETRONORTE, Brasilia (Brazil); Oliveira, A.L. [Eletricidade da Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil)

    1991-12-31

    The necessity of complementary assays of disruptive tension under normalized atmospheric pulses and residual tension on lightning arresters, as well as the adequate use of a statistical treatment of its results are commented. Some statistical methods and its applicability on lightning arresters characteristics surveys, and its quality control are proposed 8 refs., 5 figs., 3 tabs.

  19. Investigation of barium-calcium aluminate process to manufacture and characterize impregnated thermionic cathode for power microwave devices; Investigacao do processo de obtencao de aluminatos de bario e calcio para construcao e caracterizacao de catodos termionicos impregnados para aplicacao em dispositivos de microondas de potencia

    Energy Technology Data Exchange (ETDEWEB)

    Higashi, Cristiane

    2006-07-01

    In the present work it is described the barium calcium aluminate manufacture processes employed to produce impregnated cathodes to be used in a traveling-wave tube (TWT). The cathodes were developed using a tungsten body impregnated with barium and calcium aluminate with a 5:3:2 proportion (molar). Three different processes were investigated to obtain this material: solid-state reaction, precipitation and crystallization. Thermal analysis, thermogravimetry specifically, supported to determine an adequate preparation procedure (taking into account temperature, time and pyrolysis atmosphere). It was verified that the crystallization showed a better result when compared to those investigated (solid-state reaction and precipitation techniques - formation temperature is about 1000 deg C in hydrogen atmosphere), whereas it presented the lower formation temperature (800 deg C) in oxidizing atmosphere (O{sub 2}). It was used the practical work function distribution theory (PWFD) of Miram to characterize thermionic impregnated cathode. The PWFD curves were used to characterize the barium-calcium aluminate cathode. PWFD curves shown that the aluminate cathode work function is about 2,00 eV. (author)

  20. Topics to study the integrated use of natural gas in the electricity with industrial focus: a methodology for optimizing its use with application in the Vale do Paraiba region (SP-Brazil); Topicos para o estudo da utilizacao integrada do gas natural na eletricidade com enfoque industrial: uma metodologia para otimizacao de seu aproveitamento com aplicacao na regiao do Vale do Paraiba

    Energy Technology Data Exchange (ETDEWEB)

    Paro, Andre C.; Borelli, Samuel J.S. [PROMON Engenharia SA, Sao Paulo, SP (Brazil); Santos, Edmilson M. [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Eletrotecnica e Energia; Fadigas, Eliane A. [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica

    2004-07-01

    After the recent announcement on the discovery of a large amount of Natural Gas (NG) in the Santos Field by PETROBRAS, use incentive policies for its consumption and consequent growth participation in the national energy matrix gained strength This paper intends to present an efficient use optimization methodology for the NG integrated to Electricity with focus on it's industrial use under the concepts of Integrated Resources Planning (IRP). Thus, the topics about NG utilization in cogeneration plants are analyzed, showing it's utilization on Electric Energy (EE) and Process Heat (Steam) supply. Its contribution to the distributed Electric Energy generation, which brings the installed generation power closer to the consumer centers and mitigates energy transmission losses, are also presented. The IRP concept is applied on the integration between industrial use and other uses of NG and on the detailing of its influence on the electric sector. Finally, a case study is presented, applying the presented methodology for the use of NG in the industry of 'Vale do Paraiba' Region (SP-Brazil), due to its industrial economy condition and easy access to the Brazilian proved reserves geographic condition. (author)

  1. Serie: Madera para construcción Acabados para madera

    OpenAIRE

    Sáenz-Muñoz, Marta; Instituto Tecnológico de Costa Rica

    2012-01-01

    Durante mucho tiempo, la madera ha sido utilizada como material de construcción para resolver principalmente objetivos estructurales; sin embargo, actualmente, el uso de la madera ha tomado mucho auge en la estética de las construcciones, para brindar apariencia y calidez. En la actualidad, el mercado ofrece una amplia gama productos para dar diversos “acabados” a la madera, los cuales sirven para resaltar la belleza de algunas de ellas, realzar características como el color y la veta, o bien...

  2. "Colaborar para Competir"

    Directory of Open Access Journals (Sweden)

    Martha Liliana Hijuelos-Cárdenas

    2015-06-01

    Full Text Available De acuerdo con Michael Porter, los Clusters se definen como “Una agrupación de empresas e instituciones relacionadas entre sí, pertenecientes a un mismo sector o segmento de mercado, que se encuentran próximas geográficamente y que colaboran para ser más competitivas”. Los Clusters son en última instancia una herramienta de competitividad basada en la cooperación de sus miembros, y es una de las estrategias recientes, en el país, para incrementar la productividad y competitividad y las apuestas productivas desde el nivel local. Y es precisamente esta cercanía geográfica de las empresas de un mismo sector, lo que a la vez que genera la competencia entre ellas, también les facilita el acceso a insumos y a conocimientos específicos y en última instancia les permite promover la innovación.

  3. Principios teatrales para docentes

    Directory of Open Access Journals (Sweden)

    R. Irene Arroyo Zúñiga

    2005-01-01

    Full Text Available Este trabajo pretende dar herramientas a los docentes para que puedan utilizarlas como parte de las actividades dentro de un plan de elección, en cualquier disciplina. Además encontrará una exposición de los elementos que componen el arte de la representación escénica, como son: 1. Expresión corporal; es la capacidad de expresar emociones partiendo únicamente de nuestro cuerpo. 2. Impostación; es la habilidad de proyectar la voz sin lastimar las cuerdas vocales. 3. Dicción; es la pronunciación correcta de las palabras. 4. Actuación; es la posibilidad de crear un personaje partiendo de los recursos expresivos y de la forma natural en que el alumno acostumbra a reaccionar. Técnica de improvisación, en éste artículo propongo una serie de seis pasos que pueden ser de gran ayuda a la hora de usar el teatro como recurso didáctico. El teatro a lo largo de la historia ha sido usado para transmitir conocimientos, valores, creencias y todo aspecto inherente a los individuos y su entorno social. Por lo tanto debemos aprovechar al máximo los beneficios que nos ofrece el teatro como educadores

  4. Bases para proyectiles dirigidos

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1959-03-01

    Full Text Available Aunque actualmente no se ha llegado a una línea general de métodos o sistemas que gobiernen un tipo característico de rampa y servicios auxiliares necesarios para el lanzamiento al espacio de proyectiles dirigidos a grandes alturas y distancias, las experiencias obtenidas en diferentes ensayos, utilizando distintos tipos de proyectiles y trayectorias balísticas, han sentado toda una serie de procedimientos, datos y conclusiones de gran valor balístico que, aun teniendo en cuenta la continua evolución del proyectil, sus formas, combustibles y alcances, se conocen ya, con bastante aproximación, las condiciones mínimas que ha de reunir una base dedicada a este tipo de lanzamientos.

  5. Registrar para avanzar

    Directory of Open Access Journals (Sweden)

    Laia Matarranz Torres

    2017-06-01

    Full Text Available El farmacéutico comunitario es un profesional sanitario con un enorme potencial para mejorar no solo el uso de los medicamentos (detectando, por ejemplo, resultados negativos de la medicación, sino también la prevención de enfermedades y la promoción de la salud pública. Sin duda, el desarrollo y el impulso que están teniendo los servicios profesionales farmacéuticos (SPF desde hace años pueden contribuir decisivamente a que este potencial se consolide de una forma definitiva, obteniendo el reconocimiento del conjunto del sistema sanitario, incluyendo tanto a otros profesionales de la salud (médicos, enfermería, medicina especializada… como a la Administración y, por supuesto, a los propios pacientes beneficiarios de estos servicios. Es cierto que la figura del farmacéutico y su ejercicio sanitario han estado tradicionalmente bien considerados por la población, pero no es menos verdad que la integración de la actividad asistencial de la farmacia comunitaria en el Sistema Nacional de Salud (SNS es, cuanto menos mejorable, y que, incluso, algunas manifestaciones ponen en entredicho de vez en cuando la labor científico-asistencial de las farmacias o generan dudas sobre su capacidad para formar parte de pleno derecho de los equipos de salud que deben trabajar de forma coordinado en la mejora de la atención sanitaria de los pacientes.

  6. The para-petroleum industry

    International Nuclear Information System (INIS)

    2002-07-01

    The para-petroleum industry includes societies that realize studies and installations for the deposits exploitation. This document presents the situation of the para-petroleum industry in 2001, the world investment growth of the activity, the french societies financial results and an inventory of the main operations in the amalgamation domain. (A.L.B.)

  7. Para-bosons and Para-fermions in Quantum Mechanics

    International Nuclear Information System (INIS)

    Cattani, M.S.D.; Fernandes, N.C.

    1982-01-01

    Within the framework of the ordinary quantum mechanics, a detailed study of the energy eigenfunctions of N identical particles using the irreducible representations of the permutation group in the Hilbert space is performed. It is shown that the para-states, as occurs with the boson and fermion states, are compatible with the postulates of quantum mechanics and with the principle of indistinguishability. A mathematical support for the existence of para-bosons and para-fermions is given. Gentile's quantum statistics is, in a certain sense, justified. (Author) [pt

  8. Generating para-water from para-hydrogen: A Gedankenexperiment.

    Science.gov (United States)

    Ivanov, Konstantin L; Bodenhausen, Geoffrey

    2018-07-01

    A novel conceptual approach is described that is based on the transfer of hyperpolarization from para-hydrogen in view of generating a population imbalance between the two spin isomers of H 2 O. The approach is analogous to SABRE (Signal Amplification By Reversible Exchange) and makes use of the transfer of spin order from para-hydrogen to H 2 O in a hypothetical organometallic complex. The spin order transfer is expected to be most efficient at avoided level crossings. The highest achievable enrichment levels of para- and ortho-water are discussed. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. "Plug" ósseo autógeno para orifícios de trepanação: nota técnica Autogenic bone plug to seal burr holes: technical note

    Directory of Open Access Journals (Sweden)

    JOSUÉ GUIMARÃES GRANHA VIALOGO

    1999-12-01

    Full Text Available Vários materiais são utilizados para ocluir os orifícios de trepanação em neurocirurgia, por motivos variados: para evitar fístula liquórica após trepanações, para auxiliar a fixação do "flap" ósseo e por motivos estéticos, na região frontal. Dentre estes materiais citamos os heterólogos (botões de silicone, miniplacas de metal, cera de osso, metilmetacrilato, gelfoam, cimento de polímero vegetal, cerâmica de hidroxiapatita, e os autólogos (pó de osso originado da trepanação, gordura, músculo, aponeurose. Os materiais heterólogos ou sintéticos podem provocar reação de corpo estranho com erosão da pele e exposição do material, tornando necessária sua retirada, em tempo variável no pós-operatório. Há cerca de três anos, o autor vem utilizando um botão ou "plug" ósseo autólogo, feito com surgicel e o pó de osso proveniente da trepanação, com bom resultado estético eliminando as desconfortáveis depressões cranianas pós-trepanação. Apresentamos a técnica de confecção deste prático `plug ósseo autólogo'. Nas neuroendoscopias, praticamente sanou-se o problema da fístula liquórica e reação de corpo estranho. Encorajamos a utilização deste botão ósseo autólogo em nosso meio, como método eficiente, econômico e biologicamente aceitável para ocluir orifícios cranianos de trepanação.Many neurosurgical procedures can be performed by a single burr hole: neuroendoscopy, microvascular decompression, stereotactic procedures, chronic subdural haematomas. It is technically difficult to suture and close the dura, located at the bottom of such holes, which can lately lead to CSF leakage. On the other hand, the surgical material used to seal the burr holes can be divided in heterogenic (metal screws, silicon plugs, gelfoam, bone wax, metilmetacrilate, hidroxiapatite, and autogenic (fat, aponeurosis, muscle, and bone dust from trephination. The heterogenic group always brings the possibility of

  10. Para compreender a ciberliteratura

    Directory of Open Access Journals (Sweden)

    Lucia Santaella

    2012-12-01

    Full Text Available http://dx.doi.org/10.5007/1807-9288.2012v8n2p229   Mediante as mídias digitais, a configuração da literatura sofreu um salto qualitativo em todos os seus aspectos. O espaço virtual gerado pelas redes de computadores funciona como um novo meio. Abre-se com ele uma miríade de oportunidades que expandem o conceito de literatura em função da emergência de novas formas de criação literária. Disso decorre que a criação, a teoria e a crítica literárias exigem a redefinição de seus paradigmas herdados da era de Gutenberg. Tendo isso em vista, este artigo está voltado para a construção textual e hipertextual no espaço digital, o que implica uma exploração do que é ciberliteratura, em que ela se cruza e em que diverge da literatura impressa, que estratégias significantes a caracterizam e como essas estratégias são interpretadas pelos usuários na sua busca de significado.

  11. para promover la salud

    Directory of Open Access Journals (Sweden)

    Ma. del Consuelo Chapela

    2002-01-01

    Full Text Available Hablar de educación a distancia sustentada en el desarrollo de la cibernética obliga a reflexionar sobre sus definiciones, objetivos y medios, especialmente si pensamos en las necesidades de la fracción de población que no tiene acceso a las posibilidades que ofrece el desarrollo tecnológico. En este trabajo se presenta e ilustra con un ejemplo práctico, una perspectiva sobre las posibilidades de la educación a distancia desde las necesidades de la promoción de la salud entre grupos de población marginada en el mundo virtual. Se propone la creación de bibliotecas itinerantes regionales que pongan a disposición de la población con acceso limitado a la información, la tecnología comunicativa necesaria para apoyar los trabajos de promoción de la salud.

  12. Para-equilibrium phase diagrams

    International Nuclear Information System (INIS)

    Pelton, Arthur D.; Koukkari, Pertti; Pajarre, Risto; Eriksson, Gunnar

    2014-01-01

    Highlights: • A rapidly cooled system may attain a state of para-equilibrium. • In this state rapidly diffusing elements reach equilibrium but others are immobile. • Application of the Phase Rule to para-equilibrium phase diagrams is discussed. • A general algorithm to calculate para-equilibrium phase diagrams is described. - Abstract: If an initially homogeneous system at high temperature is rapidly cooled, a temporary para-equilibrium state may result in which rapidly diffusing elements have reached equilibrium but more slowly diffusing elements have remained essentially immobile. The best known example occurs when homogeneous austenite is quenched. A para-equilibrium phase assemblage may be calculated thermodynamically by Gibbs free energy minimization under the constraint that the ratios of the slowly diffusing elements are the same in all phases. Several examples of calculated para-equilibrium phase diagram sections are presented and the application of the Phase Rule is discussed. Although the rules governing the geometry of these diagrams may appear at first to be somewhat different from those for full equilibrium phase diagrams, it is shown that in fact they obey exactly the same rules with the following provision. Since the molar ratios of non-diffusing elements are the same in all phases at para-equilibrium, these ratios act, as far as the geometry of the diagram is concerned, like “potential” variables (such as T, pressure or chemical potentials) rather than like “normal” composition variables which need not be the same in all phases. A general algorithm to calculate para-equilibrium phase diagrams is presented. In the limit, if a para-equilibrium calculation is performed under the constraint that no elements diffuse, then the resultant phase diagram shows the single phase with the minimum Gibbs free energy at any point on the diagram; such calculations are of interest in physical vapor deposition when deposition is so rapid that phase

  13. Marcadores para la Realidad Aumentada para fines educativos

    Directory of Open Access Journals (Sweden)

    María Reina Zarate Nava

    2013-12-01

    Full Text Available La Realidad Aumentada (AR es considerada por algunos expertos como la tecnología en crecimiento para el 2014, en diferentes sectores: ingeniería, educación, juegos y negocios, siendo este último el más usado en él 2013. Sin embargo en el sector educativo la AR se presenta en algunos proyectos que se han desarrollado para diferentes áreas de las ciencias, como Química, Física y Matemáticas, lo anterior con el objetivo de facilitar el proceso de Enseñanza-Aprendizaje. En el presente artículo se presenta el modelo de patrones utilizado para un Proyecto AR enfocado en Química, el cual presenta un conjunto de patrones que fueron valorados para facilitar el rastreo de los objetos y a su vez el entendimiento de algunos materiales de los laboratorios de Química I.

  14. Algoritmos para problemas de empacotamento

    OpenAIRE

    Eduardo Candido Xavier

    2006-01-01

    Resumo: Neste trabalho estudamos diversos problemas de empacotamento considerados NP-difíceis. Assumindo a hipótese de que P ? NP, sabemos que não existem algoritmos eficientes (complexidade de tempo polinomial) exatos para resolver tais problemas. Uma das abordagens consideradas para tratar tais problemas é a de algoritmos de aproximação, que são algoritmos eficientes e que geram soluções com garantia de qualidade. Neste trabalho apresentamos alguns algoritmos aproximados para problemas de e...

  15. Uma ferramenta para planejamento de estudos para concursos

    Directory of Open Access Journals (Sweden)

    Leonardo Pimentel

    2015-11-01

    Full Text Available De acordo com a constituição brasileira, a única forma de se tornar um empregado do governo é passar em um concurso público. O exame de conhecimento do cargo é um dos componentes mais importantes de um concurso. Estudar para esse exame é uma tarefa que requer planejamento. Um meio de obter um bom planejamento é construir uma grade de horários que relacione as matérias a serem estudadas com os respectivos horários disponíveis para o estudo. Esse tipo de problema se assemelha bastante à gerência de projetos, em que se procura estabelecer a distribuição das atividades ao longo do tempo disponível. Assim, torna-se interessante explorar a dinâmica de estudos para concursos como um projeto. O presente trabalho apresenta a ferramenta de apoio ao estudos - Passe-me, baseada no ciclo PDCA (do inglês, Plan-Do-Check-Act. Por se tratar de uma ferramenta web, o tempo de resposta para produzir uma grade de estudos é fundamental. A ferramenta faz uso de algoritmo genético para calcular a grade de horários priorizando a velocidade de resposta. A ferramenta foi avaliada em diferentes cenários de uso e obteve desempenho satisfatório durante a produção da grade de estudos.

  16. Treatment options for osteoporosis and decision making criteria: 2009 Alternativas de tratamiento para osteoporosis y criterios de decisión: 2009

    Directory of Open Access Journals (Sweden)

    Guillermo Ortiz-Luna

    2009-01-01

    . Afortunadamente, cada vez contamos con más y mejores estrategias desarrolladas por la OMS para identificar oportunamente a las personas en riesgo de sufrir una fractura; actualmente es posible definir este riesgo para los siguientes diez años. Lo cual, aunado a métodos cada vez más sensibles para establecer diagnósticos definitivos y opciones de tratamiento costo-eficaces para evitar caídas y disminuir significativamente la presentación de fracturas, permite a quien toma decisiones en este problema diseñar y poner en práctica planes de atención sustentados en la mejor evidencia científica, que son motivo de esta revisión. Varios países empiezan a informar un abatimiento del número de fracturas, después de haber establecido programas dirigidos a este fin desde hace 30 años. Contamos con medicamentos que han demostrado su eficacia para abatir la presentación de la primera fractura o de fracturas recurrentes de manera costo-eficiente, estos se pueden dividir para su estudio de acuerdo al mecanismo de acción que los vuelve eficaces. Así, aquellos que frenan la destrucción del tejido óseo se clasifican como anti-catabólicos, los que estimulan la formación de tejido óseo nuevo son anabólicos, los que tienen ambas acciones se conocen como de acción mixta. En todos los casos, el tejido remanente, previamente formado o en vías de destrucción, que se fortalecerá o el tejido de nueva formación, requieren medidas para garantizar que el proceso de mineralización suceda normalmente y se genere hidroxiapatita o un compuesto con características similares para que la eficiencia biomecánica del tejido realmente mejore a largo plazo. Esta revisión incluye algunas perspectivas que seguramente mejorarán nuestro manejo de la osteoporosis en el futuro inmediato y que se deberán reflejar en una disminución del impacto de este problema en México.

  17. ¿Argumentar para definir o definir para argumentar?

    OpenAIRE

    Silva, Luz; Samper, Carmen

    2013-01-01

    Se presenta y se ilustra un marco de referencia de un estudio en curso para obtener el título de Maestría en Docencia de la Matemática de la Universidad Pedagógica Nacional (Colombia); estudio sobre la conexión entre las acciones de definir y argumentar, que puede contribuir a la práctica de profesores en ejercicio y en formación. La habilidad para construir una definición es un posible indicio de comprensión, mientras que saberla de memoria no garantiza la comprensión del concepto (Vinner, 1...

  18. Taller para desarrollar la creatividad

    OpenAIRE

    MARTÍNEZ GUEROLA, BEATRIZ

    2015-01-01

    [ES] Partimos de la base de que la creatividad es una capacidad realmente valiosa, no solo para el ámbito artístico, si no para cualquier aspecto de la vida. Este proyecto está enfocado a un taller diseñado para que a partir de técnicas de expresión gráfico-plásticas podamos estimular y desarrollar la creatividad, principalmente en niños de tercer ciclo de primaria. Con este proyecto relacionamos el arte y la creatividad que se asocia a esté con la educación. Martínez Guerola, B. (2015). T...

  19. Exhibidor de cinturones para Montagne

    OpenAIRE

    Galletti, Julia

    2017-01-01

    En el exhibidor de cinturones diseñado para la marca de ropa deportiva Montagne se produjo un trabajo estético-formal en relación a la simbología característica de la marca. Su principal característica es ser un exhibidor 360°, es decir que desde cualquier punto de vista se puede obtener un buen panorama del producto expuesto. Está confeccionado en materiales livianos para facilitar su movilidad dentro del local estipulado (exhibición en vidriera o mostrador). Asimismo, es totalmente desarmab...

  20. Colombia competente para la paz

    Directory of Open Access Journals (Sweden)

    Norma Sofía Vanegas Torres

    2013-07-01

    Full Text Available La paz y la convivencia en Colombia demandan el desarrollo de un enfoque humanístico, una competencia particular que como las restantes competencias implican un saber y un saber hacer dentro de un contexto, pero que en este caso se relacionan más concretamente con el saber vivir. Este artículo analiza el desarrollo de una posible de competencia para la paz y analiza la importancia de la academia como medio para su desarrollo e instrumentalización. Se analizan al mismo tiempo las connotaciones de esta competencia en el marco de la sociedad posmoderna contemporánea.

  1. Compósito para fabricação de implantes reabsorvíveis para osteossíntese: avaliação da biocompatibilidade em coelhos Composite for the fabrication of resorbable implants for osteosynthesis: biocompatibility evaluation in rabbits

    Directory of Open Access Journals (Sweden)

    Emily Correna Carlo

    2009-02-01

    Full Text Available A biocompatibilidade, a osseointegração e a reabsorção de compósitos contendo 10% de hidroxiapatita (HAP-91® e 90% de polihidroxibutirato foram analisadas após implantação em defeitos ósseos em coelhos. Foram obtidos dados clínicos, radiográficos, histológicos e histomorfométricos aos oito, 45 e 90 dias após a realização da cirurgia, sendo os resultados comparados aos de defeitos não-preenchidos. Não foram observadas diferenças significativas entre os grupos para os parâmetros clínicos avaliados. Radiografias demonstraram o compósito em contato direto com osso aos 45 e 90 dias. Tecido ósseo se formou normalmente no defeito e na interface com o material, quando comparado ao controle. Não foi observado infiltrado inflamatório. Em todos os dias, a porcentagem de tecido ósseo foi maior que a de tecido conjuntivo (P=0,001 aos 8 e 45 dias e 0,022 aos 90 dias dentro dos defeitos. Foram observados tecidos ósseo e conjuntivo na interface com o compósito, sendo o último significativamente maior que o primeiro aos 90 dias (P=0,004. Foram observados sinais de reabsorção do compósito: células gigantes na superfície de fragmentos do compósito separados do bloco original. Portanto, pode-se concluir que o compósito é biocompatível em coelhos, reabsorvível e se integra ao tecido ósseo.Biocompatibility, osseointegration, and resorption of a 10% hydroxyapatite (HAP-91® - 90% polyhydroxybutyrate composite were analyzed after implantation in rabbits´ bone defects. Clinical, radiographic, histologic and histomorphometric data were collected on the 8th, 45th, and 90th days after surgery and the results were compared to those of unfilled defects. No significant differences between groups for the evaluated clinical parameters existed. Radiographs showed bone-composite direct contact. Bone tissue was formed normally in the defect and at the composite-tissue interface when compared to the control. No inflammatory infiltrated was

  2. NASVD and MNF techniques and your application noise reduction in gamma-ray spectrometric data; As tecnicas NASVD e MNF e sua aplicacao na reducao de ruidos em dados gamaespectrometricos

    Energy Technology Data Exchange (ETDEWEB)

    Cavallaro, Francisco de Assis, E-mail: assisfc@yahoo.com.br, E-mail: assis@agp-la.org [Departamento de Geologia Sedimentar e Ambiental, DGSA, Instituto de Geociencias, IG, Universidade de Sao Paulo, SP (Brazil); AGPLA, AeroGeoPhysica Latinoamerica, Sao Paulo, SP (Brazil); Portugal, Rodrigo S.; Bizuti, Ariathemis M., E-mail: portugal@ige.unicamp.br, E-mail: ambizuti@ige.unicamp.br [Departamento de Geologia e Recursos Naturais, DGRN, Instituto de Geociencias, IG, Universidade Estadual de Campinas, SP (Brazil); Silva, Adalene M., E-mail: adalene@unb.br [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Geociencias. Dept. de Geoquimica e Recursos Minerais (GRM)

    2009-04-15

    The radioactive decay is a random process, and the measurement precision is ruled by statistical laws. The counting ratios of the profiles are always noisy when analyzed for short periods, such as one second per measurement. Corrections made at the end of conventional processing in the airborne gamma-ray spectrometric method data are not enough to remove and minimize, or even reduce considerably, the spectrum's originated noise. Two statistic methods that act locally in collected data, in the spectrum domain, have been suggested by literature to remove such remaining noises, the Noise-Adjusted Singular Value Decomposition - NASVD and Maximum Noise Fraction - MNF. These methods produce a significantly noise reduction. In this work both methods were applied in an area comprehended by two blocks, I and II, of the airborne survey that covers the west area of Mineral Province of Tapajos between Para and Amazon states. The filtered and non-filtered data with the NASVD and MNF techniques were processed with the Lasa's parameters. The comparison of results between maps and profiles shows that both methods are valuable, since there was resolution gain in these products. (author)

  3. MODELO PARA LA CREACIÓN DEL CONOCIMIENTO PARA PYMES

    Directory of Open Access Journals (Sweden)

    Marino Valencia Rodríguez

    2009-01-01

    Full Text Available La creciente importancia del conocimiento, como nuevo factor de producción, hace que la creación y transferencia se convierta en una de las principales prioridades de las organizaciones. El presente artículo describe tanto los fundamentos de la teoría de los recursos y capacidades de la empresa como el enfoque de la gestión del conocimiento, con sus procesos de generación y transferencia del conocimiento. Estos sirven de guía básica teórica para alcanzar el siguiente objetivo: Diseñar un modelo de generación y transferencia de conocimiento para los procesos de dirección, gestión humana y del conocimiento para PyMES, con el fin de que éstas alcancen mayores niveles de competitividad. El modelo se diseña, a partir del direccionamiento estratégico de la organización. Está conformado por tres etapas, articuladas con elementos y actividades. Las acciones se enfocan en dos factores clave de éxito: la cultura organizacional y la formación. La utilización del modelo permitirá a las PyMES optimizar los recursos y capacidades disponibles, lo cual se refleja en el desempeño del trabajador y en el fortalecimiento de la cultura organizacional.

  4. Application of low doses of ionizing radiation in the Brazilian fruit tucuma (Astrocaryum vulgare Mart.); Aplicacao de baixas doses de radiacao ionizante no fruto brasileiro tucuma (Astrocaryum vulgare Mart.)

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Antonio Luis dos Santos; Lima, Keila dos Santos Cople; Araujo, Leandro Moreira, E-mail: santoslima@ime.eb.b, E-mail: keila@ime.eb.b [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Gody, Ronoel Luiz de Oliveira; Pacheco, Sidney, E-mail: ronoel@ctaa.embrapa.b, E-mail: sidney@ctaa.embrapa.b [EMBRAPA Agroindustria de Alimentos (CTAA), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    The tucuma (Astrocaryum vulgare Mart.) is a native fruit of Amazonia, occurring mainly in the state of Para, but also found in the Brazilian northeast states and in the Brazilian central-western states. The tucuma is considered an excellent source of carotenoids with a very high concentration of {beta}-carotene, which is a precursor of vitamin A. In addition to carotenoids it is an important source of vitamin B2 (riboflavin) in fruits. This study aimed to analyze the effects of gamma radiation on the nutritional value of tucuma. The fruits were irradiated at doses of 0.5, 1.0 and 2.0 kGy irradiator with a source of cesium 137. The carotenoids were determined by spectrophotometry. The analysis of {alpha} and {beta}-carotene, thiamine, riboflavin were carried out by high performance liquid chromatography (HPLC). The {beta}-carotene accounts for 80% of total carotenoids in tucuma, and with a dose of 2 kGy, it showed the highest reduction of {beta}-carotene, about 7.5% in relation to the control. The tucuma fruit showed high levels of riboflavin from 0.183 to 0.222 {mu}g 100 g{sup -1}, and maintained stability after the gamma radiation process. However, it had low levels of thiamine from 0.050 to 0.033 {mu}g 100 g{sup -1}, and irradiated at a dose of 2 kGy showed significant reductions of thiamine, about 34% in relation to the control. (author)

  5. Coccocypselum pulchellum (Rubiaceae, nuevo registro para Argentina

    Directory of Open Access Journals (Sweden)

    Elsa L. Cabral

    2007-01-01

    Full Text Available Se cita Coccocypselum pulchellum por primera vez para Argentina, en Predio Guaraní, Misiones. Esta es la tercera especie de Coccocypselum registrada para la flora de Argentina junto con C. hasslerianum y C. lanceolatum. Se incluyen descripciones, ilustraciones y una clave para reconocer las tres especies argentinas de Coccocypselum.

  6. Principal component analysis for verifying {sup 1}H NMR spectral assignments. The case of 3-aryl (1,2,4)-oxadiazole-5-carbohydrazide benzylidene; Aplicacao de analise de componentes principais para verificacao de atribuicoes de sinais nos espetros de RMN 1H. O caso dos 3-aril (1,2,4)-oxadiazol-5-carboidrazida benzilidenos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Joao Bosco P. da; Malvestiti, Ivani; Hallwass, Fernando; Ramos, Mozart N. [Pernambuco Univ., Recife, PE (Brazil). Dept. de Quimica Fundamental]. E-mail: paraiso@ufpe.br; Leite, Lucia F.C. da Costa [Universidade Catolica de Pernambuco, Recife, PE (Brazil). Dept. de Quimica; Barreiro, Eliezer J. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Faculdade de Farmacia

    2005-06-01

    The {sup 1}H NMR data set of a series of 3-aryl (1,2,4)-oxadiazole-5-carbohydrazide benzylidene derivatives synthesized in our group was analyzed using the chemometric technique of principal component analysis (PCA). Using the original 1H NMR data PCA allowed identifying some misassignments of the proton aromatic chemical shifts. As a consequence of this multivariate analysis, nuclear Overhauser difference experiments were performed to investigate the ambiguity of other assignments of the ortho and meta aromatic hydrogens for the compound with the bromine substituent. The effect of the 1,2,4-oxadiazole group as an electron acceptor, mainly for the hydrogens 12,13, has been highlighted. (author)

  7. Viability evaluation of the reading system by CCD for application at the Fricke xylenol gel dosimetry developed by IPEN-Sao Paulo, Brazil; Avaliacao de viabilidade do sistema de leitura por CCD para aplicacao na dosimetria Fricke xilenol gel desenvolvido no IPEN-Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Mangueira, Thyago Fressatti; Dias, Daniel Menezes; Campos, Leticia Lucente, E-mail: thyagomangueira@usp.b, E-mail: dmdias@ipen.b, E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    The use of chambers with coupled charge devices - CCD, is already used by research centres for the dose evaluation applying the Fricke xylenol gel dosemeter. This work evaluates the application of this optical reading technique for the FXG developed at the IPEN, Sao Paulo, Brazil

  8. Production and characterization of compounds based on MgB{sub 4}O{sub 7} for application in dosimetry; Producao e caracterizacao de compostos a base de MgB{sub 4}O{sub 7} para aplicacao em dosimetria

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Luiza Freire de

    2016-07-01

    Many materials with luminescent properties are used for ionizing radiation dosimetry through the thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques. Detectors based on lithium fluoride (LiF), calcium sulphate (CaSO{sub 4}) and aluminum oxide (Al{sub 2}O{sub 3}), doped or codoped with various elements, are the TL or OSL commercial dosimeters most widely used currently. However, several researches are focused to the development of new TL /OSL materials in intention to enhance the dosimetric properties, in view that no TL/OSL dosimeter has all the ideal characteristics for monitoring the radiation. In this context, magnesium tetraborate (MgB{sub 4}O{sub 7}), which has been presented in the literature as a material for dosimetry TL, was investigated in this work. As there are no reports on the structural characterization of this material or regarding to its applicability on OSL dosimetry, the proposal of the present work was to develop compounds based on MgB{sub 4}O{sub 7}, with different doping, by solid state synthesis. It was made the structural, optical, TL and OSL characterization of the compound to verify it feasibility for application on radiation dosimetry. Initially, it was determined the calcination temperature and time for MgB{sub 4}O{sub 7} formation, with the use of thermal analyses and x ray diffraction. The ideal calcination was found at 900 °C for 7 hours. It were produced , in powder form, the compounds: MgB{sub 4}O{sub 7}, MgB{sub 4}O{sub 7}:Dy, MgB{sub 4}O{sub 7}:Dy,Li, MgB{sub 4}O{sub 7}:Ce, MgB{sub 4}O{sub 7}:Ce,Li, MgB{sub 4}O{sub 7}:Nd and MgB{sub 4}O{sub 7}:Nd,Li. For TL and OSL analyses it were produced pellets sintering at 950 °C for 2 hours. The radioluminescence (RL) analyses of MgB{sub 4}O{sub 7}:Dy and MgB{sub 4}O{sub 7}:Dy,Li shows wavelength emissions at 490, 590, 670 and 760 nm. For MgB{sub 4}O{sub 7}:Ce and MgB{sub 4}O{sub 7}:Ce,Li RL was observed wide emission band in the ultraviolet region. For the MgB{sub 4}O{sub 7}:Nd and MgB{sub 4}O{sub 7}:Nd,Li RL were not observed emission from the ultraviolet to infrared. With the results obtained from the TL characterization, it were also discussed aspects such as: effect of sintering and dopant concentrations in emissions, influence of doping and codoping with Li in MgB{sub 4}O{sub 7} matrix, thermal treatment reuse, TL signal reproducibility, dose response curve , relative sensitivity and it were analyzed the kinetic parameters of the TL emission curves. The OSL analyses of MgB{sub 4}O{sub 7}:Dy,Li,MgB{sub 4}O{sub 7}:Ce,Li and MgB{sub 4}O{sub 7}:Nd,Li indicated that the compounds have high cross section for photoionization to the wavelength emitted by blue LEDs, and from three compounds analyzed the MgB{sub 4}O{sub 7}: Ce,Li showed greater intensity. The partial preheating and partial cleaning methods allowed to elucidate the OSL phenomenology in compounds. (author)

  9. Study of phase transformation of U-2,5Zr-7,5Nb e U-3Zr-9Nb alloys for application in advanced nuclear fuel; Estudo das transformacoes de fases nas ligas U-2,5Zr-7,5Nb e U-3Zr-9Nb para aplicacao em combustivel nuclear avancado

    Energy Technology Data Exchange (ETDEWEB)

    Pais, Rafael Witter Dias

    2015-07-01

    Metal fuels are relevant in the nuclear area due to the versatility of its use in the nuclear fuel cycle. Among the alloys of uranium investigated with high potential for use in nuclear power reactors, U-Zr-Nb alloys appear as an important alternative because of their superior physico-chemical and metallurgical properties. These alloys have also potential for use in nuclear testing, research and production radioisotopes of high performance nuclear reactors. Therefore, the development of these alloys is strategic since they are planned to be used in national reactors as RMB (Brazilian Multipurpose Reactor) and LABGENE (Electrical Generation Core Laboratory), currently under development in Brazil. In this work it was realized a extensive study in the scope of the manufacturing, heat treatment and phase transformations of U-2,5Zr-7,5Nb (m/m%) and U-3ZR-9NB (m/m%) fuel alloys. Ingots of both alloys were produced employing a specific methodology developed in this study. This methodology comprised the melting process in a vacuum induction furnace at high temperatures (1500 °C) and thermal-mechanical processing to break the as-cast structure. Samples with typical dimensions (17 x 7 x 2.5 mm) free from macrostructural defects were homogenized at 1000 °C in vacuum of 10{sup -5} torr for 17.5 hours with a 10°C/min cooling rate until to 820 °C and, subsequently, quenched in water. The samples, randomly selected, were subjected to isothermal treatment tests under different conditions of time and temperature. Isothermal treatments for transformation and retention phases were carried out in a special assembly designed for this work. After the tests, the samples were characterized by the usual phase characterization techniques with particular emphasis for the X-ray diffraction technique. In this way, the Rietveld refinement method was applied. In the case of uranium based alloys it is quite challenging due to the lack of data in the literature. In this work a strategy for the Rietveld refinement with an extensive study of refinement parameters was established. The results allowed to establish a comparative study with the few results available in the literature and to obtain the TTT diagrams of initial transformation for both alloys. Finally, this work provides significant innovations to the field of knowledge of the alloys studied which will contribute to the development of nuclear fuel for high performance nuclear reactors. (author)

  10. Whole-body magnetic resonance imaging for staging and follow-up of pediatric patients with Hodgkin's lymphoma: comparison of different sequences; Aplicacao da ressonancia magnetica de corpo inteiro para o estadiamento e acompanhamento de pacientes com linfoma de Hodgkin na faixa etaria infanto-juvenil: comparacao entre diferentes sequencias

    Energy Technology Data Exchange (ETDEWEB)

    Nava, Daniel; Oliveira, Heverton Cesar de, E-mail: daniel@centrus.com.b [Universidade Federal de Sao Paulo (UNIFESP/EPM), SP (Brazil). Dept. de Diagnostico por Imagem; Luisi, Flavio Augusto; Lederman, Henrique Manoel [Universidade Federal de Sao Paulo (UNIFESP/IOP/GRAACC), SP (Brazil). Inst. de Oncologia Pediatrica. Grupo de Apoio ao Adolescente e a Crianca com Cancer; Ximenes, Andrea Regina da Silveira [Clinica Centrus, Campinas, SP (Brazil)

    2011-07-01

    Objective: to compare the performance of the T1, T2, STIR and DWIBS (diffusion-weighted whole-body imaging with background body signal suppression) sequences in the staging and follow-up of pediatric patients with Hodgkin's lymphoma in lymph node chains, parenchymal organs and bone marrow, and to evaluate interobserver agreement. Materials and methods: the authors studied 12 patients with confirmed diagnosis of Hodgkin's lymphoma. The patients were referred for whole body magnetic resonance imaging with T1-weighted, T2-weighted, STIR and DWIBS sequences. Results: the number of lymph node sites characterized as affected by the disease on T1- and T2-weighted sequences showed similar results (8 sites for both sequences), but lower than DWIBS and STIR sequences (11 and 12 sites, respectively). The bone marrow involvement by lymphoma showed the same values for the T1-, T2-weighted and DWIBS sequences (17 lesions), higher than the value found on STIR (13 lesions). A high rate of interobserver agreement was observed as the four sequences were analyzed. Conclusion: STIR and DWIBS sequences detected the highest number of lymph node sites characterized as affected by the disease. Similar results were demonstrated by all the sequences in the evaluation of parenchymal organs and bone marrow. A high interobserver agreement was observed as the four sequences were analyzed. (author)

  11. Study and characterization of ceramic materials from natural origin for application in jewellery design using laser texturing as innovation; Estudo e caracterizacao de materiais ceramicos de origem natural para aplicacao no design de joias utilizando a texturizacao a laser como diferencial de inovacao

    Energy Technology Data Exchange (ETDEWEB)

    Elesbao, T.R.; Carus, L.A.; Tabarelli, A.C.; Vieira, R.P.; Takimi, A.S., E-mail: taianeelesbao@hotmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Departamento de Materiais

    2012-07-01

    Technological development has been largely responsible for changes in the jewelry market. Seeking to contribute to the development of new products, this study analyzed the technique of laser texturing, aiming to add commercial and aesthetic values to the mother of pearl, material used in the jewelry field. The methodology was divided into physico-chemical characterization of the mother-of-pearl and of the resulting residue of laser texturing and analysis of the interaction of laser with the surface of the mother-of-pearl. The characterizations carried out were: Infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. Results indicate that the studied material is composed mainly by the aragonite crystal phase, different from that resulting residue from texturing process. Although the process remove some of the gem material, the effect water characteristic of the mother-of-pearl is maintained, suggesting that technology combined with research and design can increase the value of this material. (author)

  12. Synthesis and characterization of CeO{sub 2} - TiO{sub 2} system for use in heterogeneous photocatalysis in photodegradation of methylene blue dye; Sintese e caracterizacao do sistema CeO{sub 2} - TiO{sub 2} para aplicacao em fotocatalise heterogenea na fotodegradacao do corante azul de metileno

    Energy Technology Data Exchange (ETDEWEB)

    Bragatto, Julia

    2016-07-01

    This study has as its goal the synthesis of a mixed oxide system type CeO{sub 2} - TiO{sub 2}, through the polymeric precursor method, to be used in heterogeneous photocatalysis. The synthesized materials were characterized by Thermogravimetry (TG), Derivative Thermogravimetry (DTG), Differential Thermal Analysis (DTA) and X-Ray Diffraction (XRD). The results of the thermal analysis showed in what temperature ranges certain events occur such as the formation of cerium oxide between 600 and 800 ° C, which refers to the crystallization of the material. Regarding the formation of titanium oxide, events between 600 and 800 ° C are perceived, which suggests the transformation of anatase to rutile phase. The XRD analysis showed no occurrence of the same phase for all materials, meaning that there is a variation in the formation of phases according to concentration of precursor for each sample. Noteworthy are the formation of CeO{sub 2} for Ce75-Ti25 and Ce50-Ti50 concentrations, with cubic crystal structure of the fluorite type. In Ce75-Ti25 and Ce25-Ti75 it is present the TiO{sub 2} in the anatase and rutile phase, with crystal structure of the tetragonal and tetrahedron type, respectively, as well as the formation of CeTi{sub 2}O{sub 6} in Ce50-Ti50 and Ce25-Ti75, with structure monoclinic. From these analyses, it is possible to see which samples, and in which temperatures of calcination the material has increased crystallinity, making the choice for their application in heterogeneous photocatalysis, aiming the degradation of methylene blue dye. Among the tested materials for methylene blue, the sample that stood out was the Ce50-Ti50, with calcination temperature of 800 °C, with values close to 50% degradation, because it was the sample that showed higher dye adsorption capacity, which is the step that precedes photodegradation. (author)

  13. Technical and economical analysis for the implementation of small scale GTL (Gas-to-liquids) technology to monetizing the associated remote offshore stranded natural gas in Brazil; Analise tecnica e economica da aplicacao da tecnologia GTL de pequena escala para a monetizacao do gas natural associado remoto offshore no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Castelo Branco, David Alves

    2008-02-15

    The volume of stranded natural gas global reserves is substantial and represents more than a third of the world's proven natural gas reserves. In Brazil, recent discoveries operated by PETROBRAS, with participation of other companies, show trend of stranded gas reserves incorporation, associated gas or not. This dissertation's main objective is to make a technical and economic analysis of the implementation of small-scale GTL technology for the exploitation of stranded associated natural gas offshore in Brazil. Thus, the dissertation held, initially, a survey of the processes of gasification and the manufacturers with technologies and projects based on these processes, for specific offshore applications. In a second stage, the conditions of the offshore environment were examined. After the confrontation of the technologies available and the operation conditions, a technological alternative has been chosen to be used in an illustrative economic analysis. The results show that GTL offshore option becomes viable at a minimum price of about US $ 40.00 / barrel. Although this value is greater than the robustness price adopted by PETROBRAS, there are prospects for the reduction of GTL technology costs. (author)

  14. Development and standardization of radioimmunoassay technique for human proinsulin determining and its use in the study of type II diabetes mellitus associated to obesity; Desenvolvimento e padronizacao da tecnica de radioimunoensaio para a determinacao de pro-insulina humana e sua aplicacao no estudo do diabetes mellitus tipo II associado a obesidade

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Martha do

    1996-12-31

    The availability of immunoassay methodology for proinsulin is important to define its physiological and pathophysiological significance in humans. Serum concentration of proinsulin are elevated in patients with type II Diabetes Mellitus (NIDDM) and recently diagnosed Type I, so a raised circulating concentration of proinsulin may serve as an early indicator of {beta} cells dysfunction. recently, in NIDDM the serum concentrations of proinsulin and its B-chain-C-peptide junctional split form, des (31-32), were found to correlate with diastolic blood pressure, a risk factor for cardiovascular disease. The development of a sensitive and specific radioimmunoassay (RIA) methodology for proinsulin has been difficult due to its low concentration in serum and the presence of proinsulin conversion intermediates in fluids and tissues. Also other potentially cross-reactive peptides, including insulin and C-peptide, can interfere in the assay. This work describe a highly specific human proinsulin RIA developed by using biosynthetic human proinsulin (hPI) as immunogen, standard and tracer. (author) 133 refs., 17 figs., 36 tabs.

  15. Application of the Life-Cycle Cost Analysis (LCCA) for established of energy efficiency standards: refrigerators sold in Brazil; Aplicacao da metodologia de analise do custo do ciclo de vida (ACCV) para o estabelicimento de padroes de eficiencia energetica: refrigeradores comercializados no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Silva Junior, Herculano Xavier da; Jannuzzi, Gilberto de Martino [Universidade Estadual de Campinas (UNICAMP), SP (Brazil); Queiroz, Guilherme de Castilho [Centro de Tecnologia de Embalagens (CETEA), Campinas, SP (Brazil)

    2006-07-01

    The goal of this paper is to present the work in the thesis developed by Silva Jr. (2005) who discusses the application of the methodologies of Life Cycle Cost Analysis (LCCA) as a tool to propose energy efficiency standards, additional to the voluntary labels already existing in the one-door Brazilian refrigerators. Another objective is to study the role of these instruments (energy efficiency labels and standards and environmental labels) as means to supply technical subsidies for the establishment of maximum level of electric energy consumption and environmental quality impact for electrical equipment in Brazil. The LCCA methodology allows to evaluate the impacts of the energy efficiency increasing in electrical equipment, resulting in important saving (energy, financial, carbon dioxide emissions avoided etc.) for the country and its citizens. The results reached in this studies offer important data to subsidize deep discussions with manufacturers and the government to stipulate minimum energy efficiency standards for the Brazilian refrigerators. Thus, with increase of 28,1% on the energy efficiency of the one-door Brazilian refrigerators in 2008 to reach a values of savings that can be in order of 54,63 TWh (with respective reduction of demand power of 208 MW), of US$ 6,23 Billions of Dollar (R$ 17,2 Billions of Reais) of reduction in the account of electric energy for the population and of approximately 22 billions of tons of CO{sub 2} not emitted on the environment after 30 years of the implantation of standard. These values, that can not be despised by government, manufacturers and consumers. One other interest of this work is to start the discussion, the possibility of the creation of environmental labelling (e.g., Green Seal - USA, Eco-label - EU etc.) that is an additional program/methodology, which, it may be utilized as support for development of technologies and for the increase of energy and environmental efficiency of the electric equipment. These labels are strategically important for Brazil to amplify the environmental programs to their products because they can facilitate the insertion of these products in the international market, at the same time, that the country gets in the increase of the quality (environmental etc.) and promotes the sustainable development around the world. (author)

  16. Application of natural Ra isotopes and {sup 234}Th as tracers of organic carbon export in Bransfield Strait, Antarctica; Aplicacao dos isotopos naturais de Ra e do Th-234 como tracadores do carbono organico exportado para o Estreito de Bransfield, Antartica

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Lucia Helena

    2011-07-01

    The Southern Ocean is the largest of several high-nutrient, low-chlorophyll (HNLC) regions in the world's oceans. This region plays a major role in regulating the global net transfer of carbon dioxide between the ocean and the atmosphere, in part because the annual photosynthetic uptake of CO{sub 2} by phytoplankton and resulting export of particulate organic carbon (POC) to the deep ocean. The element thorium has multiple radioisotopes that have emerged collectively as a powerful set of tracers for particle associated processes in the oceans. Of all the Th isotopes, {sup 234}Th (half-life 24.1 d) has been the focus of increasing attention and application in the past years. The production of {sup 234}Th from {sup 238}U, coupled with the conservative behavior of {sup 238}U in seawater, makes the source of {sup 234}Th easy to characterize. Moreover, the half-life of {sup 234}Th is sufficiently short to make it sensitive to the short-term (e.g. seasonal) changes that occur in the upper water column of the open ocean or in sediments or water column in coastal areas. Because of its very particle reactive behavior, {sup 234}Th is removed from a parcel of water in only two ways, through decay and through particle flux. Therefore, a steady-state 1D activity balance can be used to calculate its flux. Natural Ra isotopes have been also widely used in marine studies to trace water masses and to quantify mixing processes. This work presents results of a collaborative research on organic carbon fluxes distribution in the Bransfield Strait in order to evaluate its influence in the CO{sub 2} drawdown. Macro-nutrients, micro-nutrients and chlorophyll-a distributions were used to examine the pathway sources. Natural radium isotopes were applied as tracers to study the movement of shelf water, while {sup 234}Th was used as a tracer of particle flux in the upper ocean, since POC export via sinking particles is the primary mechanism of carbon sequestration in the Southern Ocean. Sea water samples for total {sup 234}Th and natural Ra isotopes were collected from 9 to 14 December 2007 on the RV Ary Rongel (Brazilian Navy). Analyses of total {sup 234}Th activities were performed by gross beta counting using a gas-flow low background proportional counter. The long lived Ra isotopes were determined by low-background high efficiency gamma spectrometry. (author)

  17. Fabrication and study of stability of Ca{sub 2}AlWO{sub 5,5} ceramic in crude petroleum for applications in petroleum industry; Fabricacao e estudo da estabilidade em petroleo cru da ceramica Ca{sub 2}AlWO{sub 5,5} para aplicacao em industria petrolifera

    Energy Technology Data Exchange (ETDEWEB)

    Yadava, Y.P.; Silva, N.D.G.; Sousa, A.G. de; Sanguinetti Ferreira, R.A., E-mail: dea.a@hotmail.co [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Engenharia Mecanica

    2010-07-01

    Perovskite-type ceramic oxides or their derivatives are used for applications in high technology because of their enormous range of physic-chemical properties with little change in structural characteristics. In this paper we report manufacture ceramic components of a new ceramic Ca{sub 2}AlWO{sub 5,5} by thermo-mechanical process. Stoichiometric amounts of chemical constituents with high degree of purity, were homogenized using a ball mill and high purity alumina balls, compacted by uniaxial pressing and annealed at 1200 deg C for 48 hours. The structural characterization studied by x-ray diffraction that this material has a typical complex ordered cubic perovskite structure. For the study the stability of these ceramics in crude petroleum circular discs of 20 mm diameter and 2 mm thickness were produced and sintering. These discs were submerged in crude petroleum for 15, 30 and 45 days and were examined at each stage by X-ray diffraction, optical microscopy and hardness testing and these results show that Ca{sub 2}AlWO{sub 5,5} are stable in crude petroleum environment. (author)

  18. Utilization of response surface for optimization of the production of a biosurfactant with application in the removal of petroleum-derived; Utilizacao de superficie de resposta para a otimizacao da producao de um biossurfactante com aplicacao na remocao de derivado de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Sarubbo, Leonie A.; Rufino, Raquel D.; Luna, Juliana M.; Farias, Charles B.B.; Santos, Valdemir A. dos [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil)

    2012-07-01

    The surfactants, amphipathic compounds capable of reducing the surface tension of aqueous media, find application in many industries, especially in the petroleum, cosmetic and food, such as dispersants, emulsifiers and surfactants. With the necessity of environmental preservation, surfactants of micro-organisms origin, in substitution of synthetic surfactants, have become very attractive, since they are biodegradable and less toxic although their production costs are still high because of the substrates used and of the purification processes involved. Considering the need to reduce costs associated with the production of microbial surfactants, a strain of bacteria of the genus Pseudomonas, isolated from the port area was cultured in medium containing low-cost agro-industrial wastes, molasses and corn steep liquor, as substrates according a central composite rotatable design (CCRD) in order to evaluate the influence of independent variables molasses and corn steep liquor concentrations on the response variable surface tension. The biosurfactant was able to reduce the water surface tension from 71 mN / m to values around 27.5 mN / m. The dispersion ability and the capacity of oil removal of the surfactant was demonstrated. The possibility of application of biosurfactants in the remediation of oil polluted environments motivates the advancement of research to develop this technology for effective use in treatment of contaminated soils and waters. (author)

  19. Wetting evaluation of silver based braze alloys onto zirconia metalized with reactive elements for application in oil well drill bots; Avaliacao do molhamento de ligas de adicao a base de prata sobre zirconia polida e metalizada com elementos ativos para aplicacao em brocas de perfuracao de pocos de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, J.C.; Silva, J.M.; Santos, P.R.F.; Nascimento, R.M.; Martinelli, A.E. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Engenharia de Materiais], Email: jocabuzo@gmail.com; Pimenta, J.S. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica

    2010-07-01

    Drill bits with hard ceramic inserts are often used on drilling operations. The cutting and crushing action of rocks will produce failures in the tricone bits, which are related to wear; total or partial rupture of the drill bit body or even the inserts; thermal shock and corrosion. The research of better drill bits with ceramic inserts thermally more stable and mechanically stronger, will lead to an increase of their lifetime, and so reducing costs of substitution and maintenance. In the present work, some silver based braze alloys were melted onto zirconia YSZ substrates metallized or not with active metals. inside a furnace with vacuum of 10{sup -5} mbar to evaluate the wetting behavior. The system with AgCuTi and the non metallized YSZ ceramic, showed low contact angles and stable interfaces, which may be appropriate for brazing metal/ceramic parts. (author)

  20. Application of the linear load normalization technique in specimens SE(T) for the evaluation of structural integrity in conducting ducts of gas and oil; Aplicacao da tecnica de normalizacao linear da carga em especimes SE(T) para a avaliacao de integridade estrutural em dutos condutores de gas e petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Piovatto, R.R.; Carvalho, A.L.M.; Bose Filho, W.W.; Spinelli, D.; Rugieri, C. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil); Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica], e-mail: betaopiovatto@gmail.com

    2006-07-01

    This aim of this work is to evaluate the fracture toughness of pipe lines under high internal pressure, used in the petroliferous industry for transportation of gas and oil. These ducts are produced from high strength low alloy steels, classified as API X60. Therefore, to simulate the stress and strain fields ahead of crack, the SE(T) specimens has been point out as the best specimen geometry. The linear load normalization technique, LLN, has been showed as a promissory technique for obtaining the J-R resistance curves. The J values were obtained following the ASTM 1820 and 1152 standards, with the coefficients modified for this specimen geometry. Side groves were executed to avoid crack tunneling and to maintaining the crack on the plane perpendicular to the loading direction. The J-R curves obtained are compatible for high ductility steels. However, the observed J values seems to high, and the factors affecting this result are discussed in this work. (author)

  1. Use of microcontroller in gamma-ray spectrometer construction using NaI(Tl) sensor, with emphasis in multichannel analyzer, to applications in nuclear and environmental geophysics; Uso de microcontrolador na construcao de espectrometro gama com sensor de NaI(Tl), com enfase em analisador multicanal, para aplicacao em geofisica nuclear e ambiental

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Nilton

    2005-07-01

    In this work of nuclear geophysical instrumentation the main purpose was the development of a gamma-ray spectrometer prototype with multi channel analyzer, since the spectroscopic amplifier until your firmware. The heart of the digital part was an ATMEL 8 bits microcontroller (AT89S8252). All circuits were made and assembled in the Laboratory of Applied Geophysical Instrumentation (LIGA) of IAG-USP. A microcontroller software was completely developed in C ANSI language using the Small Device C Compiler version 2.4.8, that is a free software distributed under General Public License (GPL). At first, microcontroller was used to change all digital circuit of one classic SCINTREX GAD-6 differential gamma-ray spectrometer. Measurement times with order of 2 days became possible, and it could work in non climate ambient. Then, after this stage, had been started the development of a multichannel analyzer (MCA) working in pulse height analyzer mode with 4096 channels capacity, to use in many kinds of nuclear detection. Besides it, was developed an automatic gain system for photopeak stabilization, by the use of one radioactive source ({sup 133}Ba). This automatic gain system is very important in the case of NaI(Tl) scintillometric detectors, due PMT sensitivity with temperature and aging of some laboratory electronic circuits. Two power supplies with high stability, using pulse width modulation (PWM) techniques were developed, in order to all system became free of electrical line break off. One PWM power polarizes a photo multiplier tube (PMT) with high voltage and another supplies remaining developed circuits. Calibration in energy using standards sources {sup 137}Cs and {sup 60}Co showed that gamma detector developed has a good linearity and low thermal drift, even working in absent of air-conditioned. Concentrations measurements of K, U and Th were made in samples of soils, vegetables, etc. (author)'

  2. Technical application of current analysis to detect broken bars in three-phase induction motors at ArcelorMittal Tubarao; A aplicacao da tecnica de analise de corrente para deteccao de barras quebradas nos motores e inducao trifasicos na ArcelorMittal Tubarao

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, Harison Araujo; Rocha, Rogerio Hubner; Oliveira Filho, Jessui de; Spinasse, Amarildo; Calente, Aderaldo [ArcelorMittal Tubarao, ES (Brazil). Dept. de Producao de Gusa e Energia

    2009-11-01

    Most modern machinery operates from three-phase induction motors that, in time, can develop faults. These faults can cause the machine to stop working or decrease its efficiency level in the productive process. When a motor suffers a fault it generates indication of defects in several ways: changing in vibrating signals, temperature variations, noises, and electromagnetic field alteration. Known as motor current signature analysis, this technique allows fault detection with mechanical and electrical origin in squirrel-cage three-phase induction motors. This technique is used within ArcelorMittal Tubarao to analyze and follow the motor's rotor broken bar tendency. At ArcelorMittal Tubarao, 450 motors are monitored, at 13200, 3300 and 440V and with power rating exceeding 55 KW. This paper will show the results of applying this technique during the last 2 years, as well as the several types of broken bars detected, fault characteristics, the type of load it operates in each fault encountered, and the fault range caused in the productive process. (author)

  3. Study of the oxygen reduction reaction using Pt-Rare earths (La, Ce, Er) electrocatalysts for application of PEM fuel cells; Estudo da reacao de reducao do oxigenio utilizando eletrocatalisadores a base de Pt-terras raras (La, Ce, Er) para aplicacao em celulas a combustivel tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Thiago Bueno

    2013-07-01

    The complexity of the oxygen reduction reaction (ORR) and its potential losses make it responsible for the most part of efficiency losses at the Fuel Cells. For this reaction the electrocatalyst witch is most appropriated and shows better performance is platinum, a noble metal that elevates the cost, raising barriers for Fuel Cells technology to enter the market. First this work focuses on reducing the amount of platinum used in the cathode, by being replaced by rare earths. The most common methods of synthesis involves a large amount of steps and this work proposed to prepare the electrocatalyst through a simpler way that would not take so many steps and time to be done. Using an ultrasound mixer the electrocatalyst was prepared mixing platinum supported on carbon black and the rare earths lanthanum, cerium and erbium oxides to be applied in a half-cell study of the ORR. The Koutecky-Levich plots shows that among the electrocatalysts prepared the Pt80Ce20/C had the catalytic activity close to the commercial BASF platinum on carbon black, suggesting that the reaction was taken by the 4-electron path. As found in some works in literature, among the rare earth used to study the ORR, cerium is the one witch shows the better performance because it is able to store and provide oxygen. This feature is of great interest for the ORR because this reaction is first order to the oxygen concentration. Results show that is possible to reduce the amount of platinum maintaining the same electrocatalyst activity. (author)

  4. Characterization of cathode materials SrCoO3 and La0,2Sr0,8CoO3 for use in solid oxide fuel cells (SOFC); Caracterizacao de materiais catodicos SrCoO3 e La0,2Sr0,8CoO3 para aplicacao em celulas a combustivel de oxido solido (SOFC)

    Energy Technology Data Exchange (ETDEWEB)

    Galvao, G.O.; Aquino, F.M; Silva, R.M.; Medeiros, I.D.M. de, E-mail: gabriela.galvao@cear.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil)

    2016-07-01

    Mixed oxide ceramics with chemical structure of ABO{sub 3} type are promising candidates for cathodes of solid oxide fuel cells (SOFC) for performing well on the electrical conductivity and thermal stability. Various methods of preparation have been studied and used for the synthesis of these materials. In this study, SrCoO{sub 3} and La{sub 0,2}Sr{sub 0,8}CoO{sub 3} perovskites were synthesized using gelatin as directing agent with the purpose of producing homogeneous and porous particles. The powders obtained at 350 ° C / 2 h were calcined at 600, 800 and 1000 ° C for 4 hours and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that gelatin is a good polymerizing agent for metal ions as the material showed characteristic peaks of perovskite, with good porosity and uniformity. Furthermore, the method of synthesis employed has advantages related to cost and toxicity, which are very low. (author)

  5. Synthesis and characterization of Ce{sub 1-x}SmXO{sub 2-(x/2)} as solid electrolyte for application in IT-SOFCs; Sintese e caracterizacao de Ce{sub 1-x}SmXO{sub 2-(x/2)} como eletrolito solido para aplicacao em IT-SOFCs

    Energy Technology Data Exchange (ETDEWEB)

    Nicodemo, J.P.; Martinelli, A.E.; Nascimento, R.M. [Universidade Federal do Rio Grande do Norte (DECM/UFRN), Natal, RN (Brazil). Dept. de Engenharia de Materiais], e-mail: juli_pivotto@yahoo.com.br; Melo, D.M.A. [Universidade Federal do Rio Grande do Norte (DQ/UFRN), Natal, RN (Brazil). Dept. de Quimica; Cela, B. [Universidade Federal do Rio Grande do Norte (PPGCEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Macedo, D.A. [Universidade Federal do Rio Grande do Norte (PPGEM/UFRN), Natal, RN (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica

    2008-07-01

    Mixed rare earth doped CeO{sub 2} oxide-based have been extensively studied for use in solid electrolytes for fuel cells. Ceramics-based CeO{sub 2} have high ionic conductivity and enable the operation of solid oxide fuel cells (SOFCs) in intermediate temperatures, in the range of 500 to 750 deg C. In this work, was investigated the Sm{sub 2}O{sub 3} doped CeO{sub 2} by Pechini method to obtain Ce{sub 0,9}Sm{sub 0,1}O{sub 1,95}. The resulting powders were characterized by the chemical composition (EDS) and crystallographic (XRD), thermal analysis (TG/ATD and DTG), and particles morphology (SEM). After calcinations of 500 and 700 deg C for 2 hours were obtained nanosized powders with crystalline structure of cubic phase type fluorite fully formed. (author)

  6. Synthesis of protons exchange polymeric membranes via co-poly-esters doped with sodium dodecyl sulfate for application in PEM fuel cells; Sintese de membranas polimericas condutoras de protons por imobilizacao de MDs em copoliesteres para aplicacao em PEM-FC

    Energy Technology Data Exchange (ETDEWEB)

    Fiuza, R.A.; Brioude, M.M.; Bresciani, D.; Jose, N.M.; Boaventura, J.S. [Universidade Federal da Bahia (IQ/UFBA), Salvador, BA (Brazil). Inst. de Quimica

    2008-07-01

    Polymers are largely studied for use in PEM-type fuel cell (Proton Exchange membrane, PEMFC). These fuel cells are based on polymer membranes as electrolyte, also called protons conductor. This work developed co-polyesters made electrical conductors by doping with sodium dodecyl sulfate. The copolymers were synthesized from the copolymerization of terephthalic and adipic acids with glycerol. The material was processed in a reactor and shaped by hot pressing, yielding homogeneous and flexible plates, with excellent surface finish. The co-polyesters were analyzed by SEM, FTIR, TG, DSC, and XRD. The thermal analysis showed that the composites were thermally stable up to about 250 deg C. The micrographics revealed the MDS homogeneously dispersed in the polymeric matrix. These copolymers showed electrical conductivity between 10-7 to 10-1 S/cm, suggesting strong potential use in PEM fuel cells. (author)

  7. Application of low-dose gamma irradiation to extend the shelf life of minimally processed Red Beet (Beta vulgaris sp. vulgaris L.), cv. Early Wonder; Aplicacao de baixas doses de radiacao gama para extensao da vida util de beterraba vermelha (Beta vulgaris ssp. vulgaris L.), cv. Early Wonder, minimamente processada

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Nilber Kenup

    2006-07-01

    This study was aimed at investigating the effects of low-dose gamma irradiation on shelf-life extension and phyto sanitary safety of minimally processed red beet with basis on physicochemical; microbiological; chemical and sensory analyses. The samples (Beta vulgaris ssp. vulgaris L.), Early Wonder cultivar, were cultivated in the experimental area of the Horticulture Sector of the Departamento de Fitotecnia of the Instituto de Agronomia, Universidade Federal Rural do Rio de Janeiro, Seropedica, RJ, as part of two experiments performed during the second semester of 2005. In each experiment, 1200 plants (40 per linear meter of terrain) were sowed. Physicochemical analyses (fresh mass; length; average diameter and total soluble solids) of the edible part of the red beets (their tuberous roots) were periodically carried out in order to assess the most appropriate time for harvest by monitoring the development of the plants. Those times were found to be 104 and 73 days after transplanting, respectively. The harvested edible part of the roots were minimally processed and separated in two groups: (1) gamma irradiated (with doses of 0.5; 1.0 and 1.5 kGy) and (2) non-irradiated (control). All samples were stored at 8 degree C. Microbiological analyses were performed during the storage period (22 and 21 days, for experiments 1 and 2, respectively) in order to evaluate the phyto sanitary quality of the samples (Salmonella sp.; coliforms and total count of mesophilic aerobic and lactic acid bacteria). The samples irradiated with 1.0 and 1.5 kGy were found to remain appropriate for consumption for 21 days, as compared to only 7 days for the control. Monitoring of chemical composition was also performed and included the determination of saccharose; glucose; fructose and vitamins B1 and B2. No difference was found between the concentrations of those vitamins in irradiated and control samples at the end of the storage period, whereas significant changes in sugar contents were detected independently of the dose. In addition, physicochemical analyses investigated the evolution of pH; total acidity; total soluble solids and ascorbic acid throughout storage. Samples from experiment 2 were also subjected to sensory analyses for overall appearance and aroma at 4 different post-irradiation times. The results indicated that the samples irradiated with 1.0 and 1.5 kGy remained good for consumption for 20 days. Therefore it can be concluded that the application of those doses extended the shelf life of the samples without harming their nutritional and sensory quality. Finally, the results indicate that the dose of 1.0 kGy is the most appropriate for the conservation of red beet among those tested. (author)

  8. Validation of the extension of the range of application and of the single system of injection for the determination of total nitrogen in petroleum and its derivatives by chemiluminescence; Validacao da ampliacao da faixa de aplicacao e do sistema unico de injecao para a determinacao de nitrogenio total em petroleos e derivados por quimiluminescencia

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Maria de Fatima Pereira dos [Fundacao Gorceix, Ouro Preto, MG(Brazil)]. E-mail: santos@cenpes.petrobras.com.br; Tamanqueira, Juliana Boechat [Universidade Federal Fluminense, Niteroi, RJ (Brazil); Magalhaes, Julio Cesar Dias [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Avaliacao de Petroleo; Oliveira, Elcio Cruz de [Transpetro, Rio de Janeiro, RJ (Brazil). Logistica e Planejamento; Vaitsman, Delmo Santiago [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica. Dept. de Quimica Analitica

    2003-12-01

    With the objectives of using a single system of injection and of extending the range of application for the method ASTM D4629/02 'Total Nitrogen in Petroleum Derivatives by the System of Injection with a Syringe and Detection by Chemo- Luminescence', it was studied a procedure by statistical validation with the objective of guaranteeing the analytical reliability of the assay and allowing the inclusion of samples of petroleum and heavy derivatives in one single methodology. The determination of total nitrogen for petroleum and derivatives is traditionally assayed using the method of Kjeldahl - a time-consuming methodology that requires a large amount of time for giving the final result, at the same time that is not recommended for concentrations below 0.1%w/w, which does not meet the requirements for the specifications of the product, in the petroleum industry. An alternative for the method of Kjeldahl is the pyro-chemo luminescence, which allows the achievement of more repetitive results for total nitrogen. In the detection of nitrogen, the technique combines the reliability of oxidative combustion with the sensitivity of chemiluminescence. Therefore, it was developed a protocol of validation in the methodology ASTM D4629/02 for the validation of the extension of the range of application and for the evaluation of the performance of the equipment in analytical conditions, according to the calibration curve. (author)

  9. Preparation of PtSnCu/C and PtSn/C electrocatalysts and activation by dealloying processes for ethanol electrooxidation; Preparacao de eletrocatalisadores PtSnCu/C e PtSn/C e ativacao por processos de dealloying para aplicacao na oxidacao eletroquuimica do etanol

    Energy Technology Data Exchange (ETDEWEB)

    Crisafulli, Rudy

    2013-06-01

    PtSnCu/C (with different Pt:Sn:Cu atomic ratios) and PtSn/C (50:50) electrocatalysts were prepared by borohydride (BR) and alcohol-reduction (AR) processes using H{sub 2}PtCl{sub 6}.6H{sub 2}O, SnCl{sub 2}.2H{sub 2}O and CuCl{sub 2}.2H{sub 2}O as metal sources, NaBH{sub 4} and ethylene glycol as reducing agents, 2-propanol and ethylene glycol/water as solvents and carbon black as support. In a further step, these electrocatalysts were activated by chemical (CD) and electrochemical (ED) dealloying processes through acid treatment and thin porous coating technique, respectively. These materials were characterized by energy dispersive X-ray, Xray diffraction, transmission electron microscopy, line scan energy dispersive Xray and cyclic voltammetry. Electrochemical studies for ethanol electro-oxidation were performed by cyclic voltammetry, chronoamperometry and in single Direct Ethanol Fuel Cell using Membrane Electrode Assembly (MEA). The anodic effluents were analysed by gas chromatography. The X-ray diffractograms of the as-synthesized electrocatalysts showed the typical face-centered cubic structure (FCC) of platinum and its alloys. After dealloying, the X-ray diffractograms showed that the Pt FCC structure was preserved. The crystallite sizes of the assynthesized electrocatalysts were in the range of <=2 nm to 3 nm and after dealloying there were no significant variations in sizes. The energy dispersive Xray analysis of the as-synthesized electrocatalysts showed a Pt:Sn and Pt:Sn:Cu atomic ratios similar to the nominal values. After chemical and electrochemical dealloying of the electrocatalysts the ranged Pt:Sn and Pt:Sn:Cu atomic ratios showed that Cu and Sn atoms were removed. However, chemical dealloying process proved to be more efficient for removing Cu and electrochemical dealloying for removing Sn. The line scan energy dispersive X-ray analysis showed that acid and electrochemical treatments were efficient to dealloying Cu and/or Sn superficial atoms of the FCC structure of Pt. The results obtained by cyclic voltammetry and chronoamperometry showed that electrocatalysts containing 30 at % or more of platinum, after chemical and electrochemical dealloying had significant improvement in electrocatalytic activity for ethanol electro-oxidation in the potential of interest. The electrocatalysts with higher efficiency for electrochemical oxidation of ethanol were PtSn/C (50:50) BR/ED > PtSnCu/C (50:40:10) AR/ED > PtSnCu/C (50:10:40) BR/CD. PtSn/C (50:50) BR/CD, PtSnCu/C (50:10:40) BR/CD, PtSnCu/C (50:40:10) AR/CD electrocatalysts and Pt/C BASF, PtSn/C (75:25) BASF commercial electrocatalysts were tested in single Direct Ethanol Fuel Cell. The results showed the following performance for ethanol electro-oxidation: PtSn/C (50:50) BR/CD > PtSnCu/C (50:40:10) AR/CD > PtSnCu/C > PtSn/C (75:25) BASF > PtSnCu/C (50:10:40) BR/CD > Pt/C BASF. (author)

  10. Implementation and application of a method for quantifying metals and non-metals in drainage water from soils fertilized with phosphogypsum; Implementacao e aplicacao de metodologia para dosagem de metais e nao metais em aguas de drenagem de solos adubados com fosfogesso

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Camila Goncalves Bof

    2010-07-01

    Phosphogypsum is a waste generated in phosphoric acid production by the 'wet process'. The immense amount of phosphogypsum yearly produced (around 150 million tons) is receiving attention from environmental protection agencies all over the word, given its potential of contamination. In Brazil, this material has been used for many decades, especially for agricultural application on cropland. Although the phosphogypsum is mainly composed of dehydrated calcium sulfate, it can have high levels of impurities, such as metals (Cd, Cr, Cu, Pb), non-metals (As and Se) and radioactive elements from natural series of {sup 232}Th and {sup 238}U. Therefore, its continuous application as an agricultural agent can result not just in soil contamination, but also contamination of the surface and groundwater due to the runoff and infiltration process. The concern associated with the contamination of aquatic environments increases; when water is used for human consumption, requiring progressive adoption of more restrictive limits. However, some of the conventional analytical techniques used to determine the maximum limit of contaminants in water have detection limits above the maximum limits established by the environmental legislation. This work was aimed to evaluate the mobility of metals and non-metals in soils and, consequently, the contamination of drainage water through greenhouse-scale leaching and transport of toxic elements from soils fertilized with phosphogypsum. Hence, methods were studied and implemented for determination of metals (Cd, Cr, Cu and Pb) using Furnace Graphite Atomic Absorption Spectrometry (GF AAS), as well as for non-metals (As and Se) using Inductively Coupled Plasma Mass Spectrometry (lCP-MS). Effects of different chemical modifiers on the determination of Cd, Cr, Cu and Pb concentration by GF AAS were also investigated. In general, it was observed that the metal and non-metal concentration were below than the actual detection limit of the equipment for all conditions of interest, indicating the low mobility of the analyzed elements in the soil column. (author)

  11. Fuzzy logic application for data correction of gamma ray profile and correlation with effective porosity of core from Resende Basin, Rio de Janeiro; Aplicacao da logica fuzzy para correcao de dados de perfil de raios gama e correlacao com porosidade efetiva de testemunhos da Bacia de Resende, Rio de Janeiro

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Francisco de Assis Leal de; Tunala, Leonardo Fernandes; Abreu, Carlos Jorge de; Lopes, Ricardo Tadeu, E-mail: pachoteki@yahoo.com.br, E-mail: leotunala@hotmail.com, E-mail: abreu@geologia.ufrj.br, E-mail: ricardo@lin.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ/CCMN), RJ (Brazil). Centro de Ciencias Matematicas e da Natureza. Inst. de Geociencias. Dept. de Geologia; Rocha, Paula Lucia Ferrucio da, E-mail: ferrucio@acd.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Martins, Ricardo Rhomberg, E-mail: ricardo301@gmail.com [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola Politenica de Engenharia; Lima, Inaya Correa Barbosa, E-mail: inaya@lin.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Centro de Tecnologia

    2010-12-15

    This work presents here a study on the porosity of cores from Resende Basin (Rio de Janeiro). The first step involved the selection, thinning of the material (core) and sample preparation for the use of porosimeter to obtain effective porosity. The material studied is sandstone, friable, coarse to very fine of three wells (GPR1, GPR2 and GPR3). The fuzzy logic (MatLab) was applied to the effective porosity data calculated from the gamma ray (GR) profile for the construction of a synthetic profile and from this we could identify the errors made in calculating the data. Then the results of porosity from the core were correlated with data from the corrected effective porosity (gamma ray profile) in order to prove the results obtained with both methods. The analysis of the synthetic porosity calculated by the fuzzy logic has shown that this is a promising method for assessing the quality of data and to obtain good fits. (author)

  12. Study of {sup 137}Cs e {sup 60}Co sorption in sediments from Saco de Piraquara de Fora, Angra dos Reis and its application for environmental monitoring; Estudo da sorcao de {sup 137}Cs e {sup 60}Co em sedimentos do Saco de Piraquara de Fora em Angra dos Reis e sua aplicacao para o monitoramento ambiental

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Ingryd Marques

    2016-08-01

    Both the suspended solid particles and the bed sediments sorb radionuclides, released in water systems. Sorption is usually represented mathematically by the distribution coefficient that is based in equilibrium between phases. Here the adsorption/desorption kinetics of {sup 60}Co and {sup 137}Cs in sea water were simulated by batch equilibrium experiments with sediments in two points (PT - 01, PT - 02) from Saco de Piraquara de Fora inlet (SPF). For both radionuclides, partition coefficient values (Kd) for the sampling point PT - 02 (509 and 385 L/kg for {sup 60}Co and {sup 137}Cs, respectively) were higher than the values determined for PT - 01 one (426 and 182 L/kg for {sup 137}Cs and {sup 60}Co, respectively). The higher values of Kd of PT-02 reflects the higher CEC (71,4 cmolc.dm{sup 3}) and content of mud < 63 μm (87%) when compared to PT-01 (CEC of 39,5 cmol{sub c}.dm{sup 3}) and mud (55%). In comparison with the values reported in the literature, the found Kd values are low, which may be related to the predominance of kaolinite, which is a clay of low sorption capacity. The Kd values with an increase in temperature of 23 deg C to 27 deg C were similar ({sup 60}Co in PT-02 and {sup 137}Cs in both sediment) or 27 ° C values were higher ({sup 60}Co the PT-01). With increasing temperature to 31 °C Kd values for the two radionuclides showed a decrease. However, increasing temperature increases the desorption of the two radionuclides for both sediments The sorption process is spontaneous and favorable for both sediments and the model of sorption can be fitted by both Freundlich and Langmuir sorption isotherms. The maximum amount of {sup 60}Co that can be sorbed on sediments were 1,64 10{sup -5} moles/g (4,12 10{sup 10} Bq/g) and 2,79 10{sup -5} moles/g (7,03 10{sup 10} Bq/g) to PT-01 and PT-02, respectively, and of {sup 137}Cs 1,99 10{sup -6} moles/g (9,70 10{sup 8} Bq/g) and 6,60 10{sup -6} mol/g (2,87 10{sup 9} Bq/g ) to PT-01 and PT-02. Two areas in SPF can potentially accumulate {sup 137}Cs: sediments located near the effluent discharge and the area located north of this site. An area in the interface of SPF and the bay of Ribeira would potentially the best accumulated of {sup 60}Co. (author)

  13. Analysis of the feasibility of applying the theory of the supply chain nanagement for the electric energy chain services of the Bahia state, Brazil; Analise da viabilidade de aplicacao da teoria da gestao da cadeia de suprimentos para a cadeia de servicos de energia eletrica do estado da Bahia

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Lydiane Abdon [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil)], e-mail: lydianeleal@yahoo.com.br; Carvalho, Claudio Bezerra de [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil). Petroleo e Gas], e-mail: claudiobcarvalho@yahoo.com.br

    2008-07-01

    This article aims to analyze the potential application of integrated management, through concepts of SCM (Supply Chain Management), in the chain of the energy industry, which is characterized by a chain of services. The prospect of incorporating new integrated management practices, through the selection of concepts and tools for supply chain management took the possibility of promoting systemic approach that includes the major components (physical, regulatory and commercial) the market of electric energy, investigating possibilities of reorganization of this important segment of the industry production chain. The proposal aims to provide a tool for planning indicative of great potential, to identify a theoretical reference in this important productive sector. The work includes qualitative analyses, which aim to map, understand and systematize the changes undertaken, with emphasis on Brazilian electric sector. It is described, in general, the characterization of the energy industry in Bahia state as a possible case study in implementing the proposed methodology. Thus, the work seeks to help the staff decision to purchase a minimum of integrated vision of possible decisions, including the dynamic interactions between market supply and demand. (author)

  14. Development and standardization of radioimmunoassay technique for human proinsulin determining and its use in the study of type II diabetes mellitus associated to obesity; Desenvolvimento e padronizacao da tecnica de radioimunoensaio para a determinacao de pro-insulina humana e sua aplicacao no estudo do diabetes mellitus tipo II associado a obesidade

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Martha do

    1997-12-31

    The availability of immunoassay methodology for proinsulin is important to define its physiological and pathophysiological significance in humans. Serum concentration of proinsulin are elevated in patients with type II Diabetes Mellitus (NIDDM) and recently diagnosed Type I, so a raised circulating concentration of proinsulin may serve as an early indicator of {beta} cells dysfunction. recently, in NIDDM the serum concentrations of proinsulin and its B-chain-C-peptide junctional split form, des (31-32), were found to correlate with diastolic blood pressure, a risk factor for cardiovascular disease. The development of a sensitive and specific radioimmunoassay (RIA) methodology for proinsulin has been difficult due to its low concentration in serum and the presence of proinsulin conversion intermediates in fluids and tissues. Also other potentially cross-reactive peptides, including insulin and C-peptide, can interfere in the assay. This work describe a highly specific human proinsulin RIA developed by using biosynthetic human proinsulin (hPI) as immunogen, standard and tracer. (author) 133 refs., 17 figs., 36 tabs.

  15. Preparation and characterization of PVA/SSA membranes with Al{sub 2}O{sub 3} nanoparticles for fuel cell applications; Preparacao de caracterizacao de membranas de PVAL/SSA na presenca de nanoparticulas de Al{sub 2}O{sub 3} para aplicacao em celulas de combustivel

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Paula N.; Pires, Alfredo T.N. [Grupo de Estudo em Materiais Polimericos - POLIMAT - UFSC, Florianopolis, SC (Brazil); Catarino, Margarida; Brandao, Lucia; Tanaka, Alfredo; Mendes, Adelio [Faculdade de Engenharia da Universidade do Porto, Porto (Portugal)

    2011-07-01

    In the present study, PVA/SSA membranes were prepared with and without the addition of Al{sub 2}O{sub 3} nanoparticles. Sulfosuccinic acid (SSA) was used as the crosslinking agent. Membranes were prepared with different amounts of SSA (26, 43 and 55 wt.%) and with 5 and 10 wt.% of nanoparticles. Crosslinking was performed at 90 degree C during 1.5 h. Membranes were analyzed by infrared spectroscopy, thermal analysis, water absorption, ion exchange capacity (IEC) and proton conductivity. The results showed that control of the crosslinking conditions, IEC value, water absorption and polymer structure are of significant importance to obtain a set of properties suitable for application in proton exchange membrane fuel cells. (author)

  16. Analysis of X-ray diffraction of the titanium dioxide (TiO{sub 2}) synthesized by the Pechini Method for application in heterogeneous photocatalysis processes; Analise de difracao de raios X do dioxido de titanio (TiO{sub 2}) sintetizado pelo metodo Pechini para aplicacao em processos de fotocatalise heterogenea

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, P.L.; Araujo, D.S.; Costa, A.C.F.M.; Oliveira, L.S.C., E-mail: palomalima_eq@yahoo.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2016-07-01

    Titanium dioxide (TiO{sub 2}) is a polymorph commonly applied to heterogeneous photocatalysis processes for being relatively inexpensive and photo - stable. It is usually found in three different crystalline phases (anatase, rutile and brookite), which directly interfere in their photocatalytic efficiency. Therefore, this study aimed to investigate the obtainment of TiO{sub 2} by Pechini method in different conditions for application in the heterogeneous photocatalysis process. For this purpose, it was evaluated by analysis of X-ray diffraction (XRD ) the behavior of TiO{sub 2} materials synthesized in proportions of 2:1 and 3:1 (titanium isopropoxide/citric acid), pyrolyzed at 300°C/3h and 400°C /h and calcined at 400°C and 500°C/1h. The results revealed that the TiO{sub 2} samples produced in the ratio of 2:1 and 3:1 isopropoxide/citric acid and calcined at 500°C/h presented the best results. (author)

  17. Discontinuous finite element formulation for bodies of revolution with application in the prevention of fragile fracture in pressure vessel of PWR reactors; Formulacao de elementos finitos descontinuos para corpos de revolucao com aplicacao na prevencao de fratura fragil em vaso de pressao de reatores PWR

    Energy Technology Data Exchange (ETDEWEB)

    Benitez Alvarez, Gustavo

    1999-08-15

    In this work, a hybrid formulation is established for bodies of revolution, based on the equation of Fourier series for the discontinuous finite element method, analogous to the one that exists in the classical finite element method. Furthermore, a methodology to analyse the prevention of fragile fracture in pressure vessel of pressurized water reactors is presented. The results obtained suggest that careful analysis must be made for non symmetric refrigeration. (author)

  18. Study of application of protective measures for the public and remediation of contaminated areas in case of nuclear and / or radiological accidents in Brazil; Estudo da aplicacao de medidas de protecao para o publico e de remediacao de areas contaminadas em caso de acidentes nucleares e/ou radiologicos no Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Diogo Neves Gomes da

    2011-07-01

    Since the radiological accident in Goiania in 1987, the IRD (Institute of Radiological Protection and Dosimetry - IRD / CNEN) has been developing tools to support decision-making processes after a nuclear or radiological accident which leads to an environmental contamination and to an exposure of individuals the public These processes include the establishment of a supporting multicriteria model, which involves the application of protective and remediation measures of contaminated areas in tropical environments. In this study, it was performed an evaluation of the efficiency of these measures in order to determine the consequences of their implementation, based on results obtained from the code SIEM (Emergency Integrated System), which constitutes an environmental mode1 developed at IRD to simulate this type of accident. In order to perform this evaluation, it was first developed a database containing descriptions of various protection/remediation measures, which could be applied nationwide. Afterwards, some basic scenarios were established, considering the environmental, housing and food characteristics of the population of the vicinity of the nuclear power plants in Angra dos Reis (state of Rio de Janeiro). Thus, the accident simulations were carried out separately containing releases of {sup 137}Cs, {sup 90}Sr and 131 I. The results showed that the dose reduction varies according to the extent and the timing of the remediation measure applied. Although it is possible to establish some basic guidelines, generic solutions are not recommended, since the resulting doses are highly dependent on the actual situation. Any decision-making process should be made case by case, according to the actual conditions of the affected area and to the occupation characteristics and use of the affected areas, considering the characteristics of the source term of contamination, the time of the year in which the accident occurs, the local agricultural practices and food habits of real people affected. For both types of area, it was observed that it would be appropriate to assign the security measures according to three criteria: (i) its efficiency in reducing the doses in the first year, (ii) its efficiency in reducing the dose of long-term and (iii) the effect of delay in implementing the measure efficiency in reducing doses. Finally, the results of this work will be complemented in the database in order to provide support for multi-criteria analysis in decisionmaking process after this type of accident. (author)

  19. Preparation and characterization of Nafion - TiO{sub 2} composite electrolytes for application in proton exchange membrane fuel cells; Preparacao e caracterizacao de eletrolitos compositos Nafion - TiO{sub 2} para aplicacao em celulas a combustivel de membrana de troca protonica

    Energy Technology Data Exchange (ETDEWEB)

    Matos, Bruno Ribeiro de

    2008-11-06

    The fabrication and characterization of Nafion - TiO{sub 2} composites, and the use of such electrolytes in PEM (Proton Exchange Membrane) fuel cell operating at high temperature (130 deg C) were studied. The operation of a PEM fuel cell at such high temperature is considered as an effective way to promote fast electrode reaction kinetics, high diffusional transport, and high tolerance to the carbon monoxide fuel contaminant. The polymer Nafion{sup R} is the most used electrolyte in PEM fuel cells due to its high proton conductivity. However, the proton transport in Nafion is dependent on the water content in the polymeric membrane. The need of absorbed water in the polymer structure limits the operation of the fuel cell to temperatures close to 100 deg C, above which Nafion exhibits a fast decrease of the ionic conductivity. In order to increase the performance of the electrolyte operating at high temperatures, Nafion-TiO{sub 2} composites have been prepared by casting. The addition of titania hygroscopic particles to the polymeric matrix aims at the enhancement of the humidification of the electrolyte at temperatures above 100 deg C. Three types of titania particles with different specific surface area and morphology have been investigated. Nafion-based composites with the addition of titania nanoparticles, in the 2.5-15 wt.% range, with nearly spherical shape and specific surface area up to approx. 115 m{sup 2}g{sup -1} were found to have higher glass transition temperature than the polymer. Such an increase improves the stability of the electrolyte during the fuel cell operation at high temperatures. The addition of titania-derived nanotubes results in a pronounced increase of the performance of PEM fuel cell operating at 130 deg C. In this composite, the high specific surface area and the tubular shape of the inorganic phase are responsible for the measured increase of both the absorption and retention of water of the composite electrolyte. Nonetheless, the polarization curves of fuel cell using the composite electrolytes exhibited an increase of the ohmic polarization associated with the addition of the insulating titania particles. As the chemical structure of Nafion was observed to be insensitive to the addition of the inorganic particles, the high performance of the composite electrolytes is a result of competing effects: the decrease of the electrical conductivity and a higher thermal stability or water absorption/retention capacity. The experimental results suggest that the Nafion-TiO{sub 2} composites are promising electrolytes for PEM fuel cells operating at temperatures above approx. 100 deg C. (author)

  20. FRANQUICIAS. Una Alternativa para Emprendedores

    Directory of Open Access Journals (Sweden)

    Jorge Enrique Silva Duarte

    2003-07-01

    Full Text Available Este artículo presenta las ventajas de las franquicias como alternativa de negocios. Para un emprendedor exitoso ya establecido es más rentable permitir el uso de su conocimiento explícito mediante el formato de negocio de su firma y recibir regalías mensuales sobre las ventas brutas, que invertir en la apertura de cada nuevo punto. Igualmente, para quien desee iniciarse como empresario, la modalidad de franquicia es muy interesante: en primer lugar, porque empieza con un negocio ya probado, utiliza la imagen extendida de la franquicia y recibe un apoyo corporativo del franquiciador; adicionalmente, detrás del formato de negocio que contrata, está el capital relacional, en otras palabras, la experticia del franquiciador, el conocimiento del mercado, la base de clientes y de proveedores y el capital humano.

  1. Financiamiento para construir la finca.

    Directory of Open Access Journals (Sweden)

    Túpac Barahona.

    1998-08-01

    Full Text Available Las instituciones financieras convencionales y no convencionales tienden a excluir de los servicios de crédito a los sectores más frágiles del campesinado, por considerarlos clientes altamente riesgosos. En este artículo, se discute el sentido económico y social que tendrían que desarrollar esquemas de financiamiento para campesinos con economías débiles, pero con un potencial de desarrollo latente.

  2. Argumentos para repensar el "desarrollo"

    Directory of Open Access Journals (Sweden)

    María Luisa Eschenhagen

    2001-06-01

    Full Text Available Con este trabajo se quiere hacer una aproximación al problema desde una perspectiva diferente, considerando nuevos argumentos que hasta hace muy poco tiempo no se habían tenido en cuenta y que se vienen formulando de una manera muy interesante en los últimos años. El objetivo del artículo es presentar tres argumentos para señalar la necesidad de repensar, desde sus fundamentos, el concepto de desarrollo.

  3. para asegurar un hijo sano

    Directory of Open Access Journals (Sweden)

    Carmen Amarilis Guerra de Castillo

    2006-01-01

    Full Text Available Esta investigación etnográfica focalizada exploró las creencias, los valores, los hábitos y los padrones comportamentales de las embarazadas diabéticas atendidas en el Hospital Doctor Enrique Tejera, quienes residen en tres comunidades urbanas pobres de la ciudad de Valencia - Venezuela, con el objetivo de encontrar el significado del cuidado de si para dichas grávidas. Se utilizó como referencial teórico el Modelo del Análisis de la Salud y la Teoría Antropológica de la Salud, siendo fundamentales para revelar aquello que estaba implícito en el comportamiento de las mujeres con relación a su cuidado. Surgieron tres temas: la salud y la enfermedad - valores culturales del cuidado de si; las prácticas del cuidado de la salud y cuidándose en el embarazo garantiza tener un hijo más saludable. Los temas culturales revelaron que las creencias, los valores, los hábitos y los patrones culturales comportamentales, conforme las tres maneras de acción identificadas, pueden ser preservadas, acomodadas y re-estructuradas para proporcionar un cuidado culturalmente congruente.

  4. Condiciones para el aprendizaje organizacional

    Directory of Open Access Journals (Sweden)

    Delio Ignacio Castañeda

    2015-01-01

    Full Text Available El propósito de esta investigación es contribuir al entendimiento de algunas condiciones que favorecen el aprendizaje en las organizaciones, específicamente el rol de la cultura del aprendizaje, la formación, la claridad estratégica y el soporte organizacional. Se emplea una metodología cuantitativa con 613 participantes, empleados de una organización pública y 2 compañías privadas, las 3 entidades ubicadas en Bogotá, Colombia. Para la realización del estudio se conformó una muestra por conveniencia, con el apoyo de los jefes de recursos humanos de 3 organizaciones con sede en la ciudad de Bogotá, Colombia. Para la recolección de los datos se utilizó una escala Likert de 5 niveles de respuesta. Los resultados sugieren que las 4 condiciones estudiadas contribuyen al aprendizaje organizacional. Los hallazgos de este trabajo orientan a profesionales sobre dónde focalizar esfuerzos para promover la adquisición y la generación de conocimiento organizacional y aporta al trabajo investigativo ampliando la evidencia empírica sobre este campo de relevancia organizacional.

  5. Condiciones para el aprendizaje organizacional

    Directory of Open Access Journals (Sweden)

    Delio Ignacio Castañeda

    2015-01-01

    Full Text Available El propósito de esta investigación es contribuir al entendimiento de algunas condiciones que favorecen el aprendizaje en las organizaciones, específicamente el rol de la cultura del aprendizaje, la formación, la claridad estratégica y el soporte organizacional. Se emplea una metodología cuantitativa con 613 participantes, empleados de una organización pública y 2 compa˜nías privadas, las 3 entidades ubicadas en Bogotá, Colombia. Para la realización del estudio se conformó una muestra por conveniencia, con el apoyo de los jefes de recursos humanos de 3 organizaciones con sede en la ciudad de Bogotá, Colombia. Para la recolección de los datos se utilizó una escala Likert de 5 niveles de respuesta. Los resultados sugieren que las 4 condiciones estudiadas contribuyen al aprendizaje organizacional. Los hallazgos de este trabajo orientan a profesionales sobre dónde focalizar esfuerzos para promover la adquisición y la generación de conocimiento organizacional y aporta al trabajo investigativo ampliando la evidencia empírica sobre este campo de relevancia organizacional.

  6. Representações sociais dos usuários hospitalizados sobre cidadania: implicações para o cuidado hospitalar

    Directory of Open Access Journals (Sweden)

    Flávia Pacheco de Araújo

    2016-08-01

    Full Text Available RESUMO Objetivo: analisar as representacoes sociais de usuarios hospitalizados sobre a cidadania no cuidado hospitalar. Método: abordagem qualitativa com referencial da Teoria das Representacoes Sociais, realizada com 31 usuarios hospitalizados no setor de clinica medica de um hospital publico, universitario. Realizou-se entrevista semiestruturada, cujos dados foram submetidos ao programa Alceste, com aplicacao de analise lexical. Resultados: os usuarios conhecem os seus direitos, e a cidadania no cuidado e entendida a luz dos direitos a saude, de modo que sejam bem atendidos do ponto de vista tecnico e humano. Conclusão: o bom trato relacional e a prestacao do cuidado tecnico-procedimental sao direitos dos usuarios; logo, a ausência de um ou de outra implica o nao respeito a sua cidadania.

  7. Nueva Sede para la Academia

    Directory of Open Access Journals (Sweden)

    Mario Camacho Pinto

    1994-06-01

    Full Text Available

    Una nueva sede adecuadamente dotada siempre estuvo en la mente de nuestros expresidentes Académicos César Augusto Pantoja, Hernando Groot, Pablo Gómez Martínez, Jorge Cavelier Gaviria y Efraim Otero-Ruiz, con quienes me tocó en suerte trabajar 12 años consecutivos, cerca de ellos a través de mi cargo de Coordinardor de la Comisión Permanente de Biblioteca y Publicaciones y de la Revista MEDICINA que se ha venido publicando sin interrupciones dentro de un compañerismo ejemplar; además de otras distinciones operativas que me inducen a expresar gratitud.

    Ahora, además, como Secretario de la Coporación por elección unánime de la Asamblea hace dos años, he sido testigo ático de una intensa, inteligente e inagotable actividad que nuestro Presidente Académico Juan Jacobo Muñoz Delgado quien siempre con el visto bueno de la Junta Directiva, mediante un acelerado ritmo de trabajo se impuso la tarea de convertir en realidad inmediata tan anhelada y necesaria idea.

    En efecto, la nueva sede fue inaugurada oficialmente el día 2 de septiembre de 1993.

    Este Editorial es la constancia escrita de tal febril actividad que para proporcionar evidencia a los lectores de “MEDICINA” resumo en breves incisos que muestran el tránsito a un estado con superávit de excepción para esta clase de instituciones:

    1. Terminación de la obra ya iniciada de la remodelación arquitectónica, tanto exterior de seguridad y aspecto como interior con suficientes y modernas instalaciones.

    2. Cerramiento total con altas y elegantes rejas metálicas y doble portería por la calle 69 y la carrera 7a.

    3. Aparcadero lujosamente adoquinado, amplio y seguro para 30 automóviles.

    4. Decoración interior estéticamente consultada, bien lograda en cortinas y clásicas lámparas de cristal obsequiadas por conocidos académicos. Un par de originales urnas precolombianas en el hall de entrada.

    5. Zona social doble, amplia

  8. TRABALHAR PARA ESTUDAR / ESTUDAR PARA TRABALHAR: REALIDADE E POSSIBILIDADES

    Directory of Open Access Journals (Sweden)

    Janes Siqueira

    2011-07-01

    Full Text Available O trabalho que apresentamos é parte da pesquisa com os estudantes das licenciaturas e da pedagogia da Universidade de Santa Cruz do Sul-UNISC-RS-Brasil. Este está inserido na linha de pesquisa: educação, trabalho e emancipação. Queremos compreender, à luz do materialismo histórico e dialético e das categorias da crítica da economia política, os significados atribuídos pelos estudantes universitários ao fenômeno trabalho e estudo. É uma pesquisa preferentemente qualitativa de natureza dialética. Para Marx, a essência da realidade humana reside no trabalho, mas a fonte de toda a riqueza está na natureza. Logo, trabalho, natureza e sociedade estão em relação dialética. Trabalho, portanto, é a ideia central articuladora, e natureza e sociedade devem ser estudadas em conexão com o trabalho. Marx trata o trabalho, no modo de produção capitalista, como impedimento ao desenvolvimento humano. Propõe o mesmo como um ato de criação e auto-expressão humana que não deve ter um valor. A compreensão dessa premissa é necessária para que os trabalhadores possam significar e ressignificar o trabalho para além da ideologia dominante. Algumas categorias aparecem como relevantes para a análise: condições de trabalho e de estudo, necessidade de formação, predominância do trabalho sobre o estudo, dificuldade de conciliar tempo de estudo e de trabalho. Na relação com o objeto de estudo, ressaltaremos a crise estrutural do capital, a desregulamentação das leis do trabalho e sua flexibilização e as contradições entre trabalho e estudo bem como quais possibilidades emancipatórias são visualizadas ou sonhadas pelos trabalhadores-estudantes. PALAVRAS-CHAVE: contradições entre trabalho e educação, condições e significados, realidade e possibilidades.

  9. Evaluation of the potential application of 2-acetylpyridine N4- phenyl thiosemicarbazones derivatives for cancer therapy and diagnosis; Avaliacao da potencial aplicacao de derivados de 2-acetilpiridina N-4 fenil tiossemicarbazonas em terapia e diagnostico oncologico

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Marcella Araugio

    2013-08-01

    Despite the wide range of antineoplastic agents available, resistance of some types of cancer and toxicity to normal cells have been identified as the main causes of treatment failure and death. The lack of early and precise diagnosis is also responsible for reducing survival of cancer patients. In this context, the development of substances with low toxicity and therapeutic potential and/or diagnosis purpose, is the major tool in an attempt to increase the survival of patients and assure the safety and efficacy of treatment. Thiosemicarbazones (TSC) are a class of synthetic compounds that have several biological activities, including antitumor. Although several studies have shown the great potential of TSC as therapeutic and / or diagnostic agents, different chemical modifications performed on this class of molecules indicate new possibilities for applications and still require further studies. The objective of this study was to evaluate the potential applicability of 2-acetylpyridine N-4-phenyl thiosemicarbazones derivatives for cancer therapy and diagnosis. The results showed that all 13 TSC tested were cytotoxic to breast and glioblastoma tumor cell lines, presenting higher in vitro antitumor activity than etoposide, an antineoplastic and inhibitor of topoisomerase II frequently used for cancer therapy. The TSC that have halogen or nitro on ortho position showed higher antitumor activity in vitro than their isomers with halogen or nitro on meta or para position of the phenyl group. H2Ac4oFPh and H2Ac4oClPh compounds showed the highest antitumor activity among all tested compounds, with IC{sub 50} in nanomolar order. These TSC induced cell death by apoptosis and oxidative stress was responsible, at least in part, for this type of cell death. The 5 mg.kg{sup -1} H2Ac4oFPh dose, administered s.c., for 4 consecutive days, did not induce important toxicity; however, the same treatment protocol was not effective for tumor growth reduction in an animal model of brain

  10. Recursos forestales para la vivienda

    Directory of Open Access Journals (Sweden)

    Olga Elgueta A.

    1984-06-01

    Full Text Available En una visita a la Universidad del Bío-Bío, realizada por el arquitecto peruano Cristián Arbaiza, dio a conocer detalladamente cuáles fueron los propósitos que tuvo el Pacto Andino -del cual es funcionario- para ocuparse de la forestación tropical y su relación con la vivienda, aspectos considerados fundamentales en el estudio de soluciones que permitan paliar el grave déficit habitacional que afecta a los países que componen el grupo subregional andino.

  11. Condiciones para el aprendizaje organizacional

    OpenAIRE

    Delio Ignacio Castañeda

    2015-01-01

    El propósito de esta investigación es contribuir al entendimiento de algunas condiciones que favorecen el aprendizaje en las organizaciones, específicamente el rol de la cultura del aprendizaje, la formación, la claridad estratégica y el soporte organizacional. Se emplea una metodología cuantitativa con 613 participantes, empleados de una organización pública y 2 compa˜nías privadas, las 3 entidades ubicadas en Bogotá, Colombia. Para la realización del estudio se conformó una muestra por conv...

  12. Entre velos: Maya para contrabajo

    OpenAIRE

    Rosa María Rodríguez Hernández

    2014-01-01

    Maya para contrabajo se materializa a partir de una imagen de Pepe Romero, cuyo texto interpreta a La decadencia de la mentira de Oscar Wilde. La estructura de Maya es binaria, especular y asimétrica; su poética obedece al juego verdad/mentira que subyace en la obra artística y en la vivencia del artista. Maya trae a la memoria las voces de los Upanishad, Schopenhauer, Shakespeare y Beethoven, influencias éstas en la obra de Wagner y, todas ellas, en la de Eliot. Los aspectos gestuales y visu...

  13. Pequenos para idade gestacional: fator de risco para mortalidade neonatal

    Directory of Open Access Journals (Sweden)

    Almeida Márcia Furquim de

    1998-01-01

    Full Text Available OBJETIVO: Estudar as variáveis contempladas na Declaração de Nascimento (DN como possíveis fatores de risco para nascimentos pequenos para a idade gestacional (PIG e o retardo de crescimento intra-uterino como fator de risco para a mortalidade neonatal. MATERIAL E MÉTODO: As variáveis existentes na DN foram obtidas diretamente de prontuários hospitalares. Os dados referem-se a uma coorte de nascimentos obtida por meio da vinculação das declarações de nascimento e óbito, correspondendo a 2.251 nascimentos vivos hospitalares, de mães residentes, ocorridos no Município de Santo André, Região Metropolitana de São Paulo, no período de l/1 a 30/6/1992, e aos óbitos neonatais verificados nessa coorte. RESULTADOS: Obteve-se a proporção de 4,3% de nascimentos PIG, significativamente maior entre os recém-nascidos de pré-termo e pós-termo, entre os nascimentos cujas mães tinham mais de 35 anos de idade e grau de instrução inferior ao primeiro grau completo. Os recém-nascidos PIG apresentam maior risco de morte neonatal que aqueles que não apresentavam sinais de retardo de crescimento intra-uterino. CONCLUSÕES: Em áreas com menor freqüência de baixo peso ao nascer, é importante investigar a presença de retardo de crescimento intra-uterino entre os nascimentos prematuros e não apenas nos nascimentos de termo. O registro da data da última menstruação (ou da idade gestacional em semanas não agregadas na DN facilitaria a detecção de PIGs na população de recém-nascidos.

  14. Para onde vai a Geografia?

    Directory of Open Access Journals (Sweden)

    Angélica Karina Dillenburg Horii

    2015-12-01

    Full Text Available O presente artigo aborda a evolução da Geografia enquanto pensamento científico, analisando seu objeto de estudo e suas categorias de análise durante todo o percurso da criação desse saber. Observa primeiramente a formação da Geografia Clássica, que teve seus princípios já instituídos na Antiguidade com Ptolomeu e Estrabão, desdobrando-se no período Iluminista com Ritter e Humboldt que fornecerão uma nova temporalidade a essa ciência. Atinge seu ápice na Modernidade Industrial com a racionalidade de Kant, onde Ratzel e La Blache utilizarão o determinismo e o possibilismo para constituir um discurso científico para a Geografia. Finaliza apontando a nova compreensão do mundo, conhecida como pós-modernismo por David Harvey (1992 ou por Milton Santos (1996 como Globalização, que junto a outros geógrafos e pesquisadores, indicam caminhos de análise dessa ciência na compreensão do seu objeto de estudo. Um diálogo entre os autores na construção do pensamento geográfico.

  15. Infraestructura para laboratorios de acceso remoto

    Directory of Open Access Journals (Sweden)

    López Luro, Francisco

    2009-01-01

    Full Text Available Las tecnologías de Internet permiten el uso de sistemas de software distribuido para el acceso en forma remota a laboratorios físicos y virtuales, para llevar a cabo actividades de investigación experimental a distancia. A partir de los marcos teóricos que definen los estructurantes de los laboratorios, los implementadores de laboratorios de acceso remoto deben diseñar y desarrollar arquitecturas de servicios que permitan un acceso flexible y controlado. Este trabajo define una infraestructura para la implementación de aplicaciones para el acceso remoto a laboratorios físicos y virtuales y para la gestión de los mismos. Se presentan conceptos que permiten extender la modalidad tradicional de conexión con un dispositivo, para llevar adelante actividades prácticas de laboratorio colaborativas y concurrentes.

  16. Internet como instrumento para la Yihad

    Directory of Open Access Journals (Sweden)

    Alfonso Merlos García

    2006-01-01

    Full Text Available Las extraordinarias ventajas que ofrece Internet lo han convertido en un instrumento clave y dinámico en la estrategia de los yihadistas. Los medios de comunicación, la clase política y las agencias de seguridad e información han tendido a concentrar sus esfuerzos en la neutralización del ciberterrorismo sin prestar suficiente atención a los múltiples usos de Internet que están haciendo los neosalafistas: para la propaganda y para la guerra psicológica, para el reclutamiento y para la financiación, para la documentación y para la planificación de atentados. Las democracias deberían considerar el coste que tendrá la derrota frente al movimiento yihadista globalizado en la batalla por el ciberespacio

  17. Inteligencia Emocional para tiempos de crisis

    OpenAIRE

    Fernández-Berrocal, Pablo

    2014-01-01

    La Inteligencia Emocional se concibe como un conjunto de habilidades, tanto básicas como complejas, dirigidas a “unificar las emociones y el razonamiento”, esto es, usar las emociones para facilitar el razonamiento y los procesos de pensamiento, y usar nuestro razonamiento para pensar de forma inteligente acerca de nuestras emociones (Mayer y Salovey, 1997). En concreto, la IE se define como una habilidad mental que incluye “la capacidad para percibir, valorar y expresar las emociones con...

  18. Sistema de realidad aumentada para aplicaciones Android

    OpenAIRE

    Fernández Sánchez, Natalia Mercedes

    2012-01-01

    El objetivo principal de este proyecto es la creación de un sistema de realidad aumentada para el sistema operativo Android con idea de que sea utilizado para la creación de un videojuego, pero que a su vez sea lo suficientemente versátil como para poder utilizarse en otro tipo de aplicaciones. De este objetivo principal podemos obtener los objetivos secundarios: - Conocer las características que ofrecen los teléfonos móviles y como éstas pueden ser aprovechadas para la crea...

  19. Paisajes para un desarrollo sustentable y participativo

    Directory of Open Access Journals (Sweden)

    Rafael Mata Olmo

    2014-11-01

    Para terminar, el texto recoge una experiencia de proyecto territorial de paisaje, la del Plan Insular de Menorca (Islas Baleares, España, aprobado en 2003. Se sintetizan sus determinaciones sobre la protección de determinados terrenos por sus altos valores paisajísticos, sus directrices para que las políticas sectoriales (turismo, agricultura, infraestructuras, etc. incorporen criterios paisajísticos, y sus iniciativas para la gestión y mejora del paisaje y para el fomento del acceso público a su contemplación y disfrute.

  20. Guias ópticos para sensores

    OpenAIRE

    Marcos de Castro Pacitti

    1993-01-01

    Neste trabalho foram estudados guias ópticos para atuarem como sensores ou em sistemas sensores. Ênfase especial foi dada em guias ópticos retangulares, para dispositivos ópticos integrados, e fibras ópticas elípticas. A analise de fibras ópticas elípticas resultou em um modelamento pratico para projeto das mesmas em aplicações onde se deseja operar com dois modos guiados, situação esta que se mostra muito atraente para implementação de diversos tipos de sensores a fibra óptica. A seguir es...

  1. Adesao ao guia alimentar para populacao brasileira

    Directory of Open Access Journals (Sweden)

    Eliseu Verly Junior

    2013-12-01

    Full Text Available OBJETIVO : Analisar a adesão ao Guia Alimentar para População Brasileira. MÉTODOS : Amostra composta por participantes do Inquérito de Saúde de São Paulo (n = 1.661 que preencheram dois recordatórios de 24 horas. Foi utilizado modelo bivariado de efeito misto para a razão entre o consumo de energia do grupo de alimentos e o consumo calórico total. A razão estimada foi utilizada para calcular o percentual de indivíduos com consumo abaixo ou acima da recomendação. RESULTADOS : Pelo menos 80,0% da população consome abaixo do recomendado para: leite e derivados; frutas e sucos de frutas; e cereais, tubérculos e raízes; aproximadamente 60,0% para legumes e verduras; 30,0% para feijões; e 8,0% para carnes e ovos. Adolescentes apresentaram a maior inadequação para legumes e verduras (90,0%, e o estrato de maior renda foi associado à menor inadequação para óleos, gorduras e sementes oleaginosas (57,0%. CONCLUSÕES : Foi observado consumo inadequado dos grupos de alimentos relacionados com aumento do risco de doenças crônicas.

  2. Leasing: una alternativa de financiamiento para PYMES

    OpenAIRE

    Bedjan, María Belén

    2008-01-01

    En la actualidad las pequeñas y medianas empresas encuentran dificultades para acceder a las líneas tradicionales de créditos bancarios. Por otro lado las empresas necesitan actualizarse constantemente para poder ser competitivas en el mercado. Es aquí donde el leasing nace como una alternativa de financiación para las PyMEs. Este trabajo pretendió demostrar la conveniencia financiera del leasing con respecto a los préstamos bancarios para la compra de maquinarias agrícolas ...

  3. Tipologia para a contabilidade ambiental

    Directory of Open Access Journals (Sweden)

    Nazlhe Faride Chein Schekaiban

    2007-06-01

    Full Text Available Este artigo revê a visão, as propostas e o desenvolvimento da contabilidade ambiental, refletindo sobre suas implicações, com a finalidade de descobrir e encontrar sua importância e situação. Para se chegar a esse resultado foi preciso realizar uma revisão epistemológica moldada e processo reflexivo de sustentabilidade e da aproximação ao usuário, da percepção da realidade contábil no México e da gerência interna das organizações. As conclusões mostram a contabilidade ambiental no México fora da re-alidade operativa do modelo contábil regional, aumentando a importância de se criar uma cultura capaz de examinar o controle da missão deste tipo de contabilidade.

  4. TV broadcasting para el desarrollo

    Directory of Open Access Journals (Sweden)

    Valerio Fuenzalida

    2015-01-01

    Full Text Available Entre los intentos de producción de televisión masiva con objetivos educativos, conscientizadores, desarrollistas o superadores hay más fracasos que éxitos. El autor propone que esto se debe a la incomprensión, por parte de los productores, de las actitudes y motivaciones de los receptores. Su análisis sobrio llama la atención sobre las características propias del medio y de sus distintos géneros y audiencias. Del análisis se desprende la necesidad de moderar las expectativas y el rechazo de las tesis que niegan al medio todo significado y potencial para el desarrollo. Fuenzalida transforma la tradicional crítica al medio y sus empresas en una llamada de atención a quienes producen es ese contexto.

  5. MERCADEO SOCIAL PARA LA SALUD

    Directory of Open Access Journals (Sweden)

    Renata Seidel

    2015-01-01

    Full Text Available Se ofrece un amplio análisis sobre la industria electoral, recordando que un candidato a presidente es "un producto para la venta". Se Desmenuzan las estrategias utilizadas en el plebiscito chileno,las elecciones norteamericanas con el NO a BUSH. El Mercadeo Social es una nueva metodología utilizada en proyectos de desarrollo a nivel de campo por ello se hace un esclarecimiento y clarifica el vínculo con la comunicación. Se agrega temas como: Los modelos de recepción de mensajes cuyos marcos conceptuales y metodologías aún no se han adaptado al potencial de esta línea de trabajo.Se analiza la agonía de las radios mineras en Bolivia en la que 42 años de historia y heroísmo se desmoronan.

  6. Entre velos: Maya para contrabajo

    Directory of Open Access Journals (Sweden)

    Rosa María Rodríguez Hernández

    2014-01-01

    Full Text Available Maya para contrabajo se materializa a partir de una imagen de Pepe Romero, cuyo texto interpreta a La decadencia de la mentira de Oscar Wilde. La estructura de Maya es binaria, especular y asimétrica; su poética obedece al juego verdad/mentira que subyace en la obra artística y en la vivencia del artista. Maya trae a la memoria las voces de los Upanishad, Schopenhauer, Shakespeare y Beethoven, influencias éstas en la obra de Wagner y, todas ellas, en la de Eliot. Los aspectos gestuales y visuales de Maya entrelazan con la danza de Pina Bausch y con la retórica (hypotiposis.

  7. Profesiones emergentes para los comunicadores

    Directory of Open Access Journals (Sweden)

    Manuel Ortiz Marín

    2015-01-01

    Full Text Available Señala el autor que en México se ha iniciado una lenta pero segura transformación del campo profesional de la comunicación. La carrera de Comunicación ocupa el octavo lugar entre las carreras más demandadas en la Educación Superior de México, que con la fuerte avalancha tecnológica y el surgimiento de la apertura de nuevos espacios sociales y político-económicos han impulsado otras formas de hacer comunicación. Dos son los campos más opcionados: medios de comunicación masiva, y lo organizacional y la publicidad, aunadas al surgimiento del marketing político. Hoy se demanda del profesional nuevas y dinámicas competencias para enfrentar escenarios laborales antes no explorados.

  8. Una minga para el posdesarrollo

    Directory of Open Access Journals (Sweden)

    Arturo Escobar

    2011-01-01

    Full Text Available El artículo sintetiza algunas conclusiones a las que han llegado movimientos sociales y académicos en las últimas dos décadas al reflexionar sobre la globalización y sus implicaciones; el modelo dominante, basado en las nociones de "desarrollo" y "modernidad", ha entrado en crisis. Por lo tanto, se hace necesario avanzar en una transición cultural que se pueda comprender como un cambio de época y no sólo como una época de cambios. Para llevar a cabo esta transformación, se deben resolver las con-tradicciones existentes entre el neodesarrollismo y el postdesarrollo, por supuesto, a favor de éste último.

  9. para su puesta en marcha

    Directory of Open Access Journals (Sweden)

    Sergio Franco Maass

    2004-01-01

    Full Text Available Los sistemas de información geográfica (SIG tienen una gran aplicación en la gestión municipal; permiten cumplir con dos objetivos fundamentales: el registro de información territorial y el análisis de problemas territoriales específicos. Con el fin de determinar la viabilidad de este tipo de tecnologías en el ámbito municipal, se enfrentó el problema de la localización de instalaciones para la disposición final de residuos sólidos urbanos en el municipio de Toluca, Estado de México. Se identifican ciertos aspectos que limitan la práctica de los SIG: la diversidad entre los municipios, los problemas administrativos, las deficiencias de la información y la carencia de recursos humanos, técnicos y financieros.

  10. Cubierta de madera para una nave industrial

    Directory of Open Access Journals (Sweden)

    Hossdorf, Heinz

    1958-05-01

    Full Text Available Para la ampliación de los talleres de Hans Schmidlin, de Basilea, Suiza, dedicados a la prefabricación de elementos de construcción de madera y metales ligeros para fachadas, se ha construido una nueva nave, rectangular, de 49x55,4 m en planta.

  11. Programa de conservacion para aves migratorias neotropicales

    Science.gov (United States)

    Deborah Finch; Marcia Wilson; Roberto Roca

    1992-01-01

    Mas de 250 especies de aves terrestres migran a Norte America durante la epoca reproductiva para aprovechar los sistemas templados. No obstante, las aves migratorias neotropicales pasan la mayor parte de su ciclo de vida en los habitat tropicales y subtropicales de paises latinoamericanos y caribefios donde viven en una asociacion cercana con las aves residentes. Para...

  12. Trabalhar para estudar/estudar para trabalhar: realidade e possibilidades

    Directory of Open Access Journals (Sweden)

    Janes Teresinha fraga Siqueira

    2011-01-01

    Full Text Available O trabalho que apresentamos é parte da pesquisa, ainda não concluída, com os estudantes das licenciaturas e da pedagogia da Universidade de Santa Cruz do Sul- UNISC-RS-Brasil. Este está inserido na linha de pesquisa: educação, trabalho e emancipação do mestrado em educação desta Universidade. Queremos compreender, à luz do materialismo histórico e dialético e das categorias da crítica da economia política, os significados atribuídos pelos estudantes universitários ao fenômeno trabalho e estudo. É uma pesquisa preferentemente qualitativa de natureza dialética. Para Marx, a essência da realidade humana reside no trabalho, mas a fonte de toda a riqueza está na natureza. Logo trabalho, natureza e sociedade estão em relação dialética. Trabalho, portanto, é a ideia central articuladora, e natureza e sociedade devem ser estudadas em conexão com o trabalho. Marx trata o trabalho, no modo de produção capitalista, como um impedimento ao desenvolvimento humano. Propõe omesmo como um ato de criação e auto-expressão humana que não deve ter um valor. A compreensão dessa premissa é necessária para que os trabalhadores possam significar e ressignificar o trabalho para além da ideologia dominante. Algumas categorias aparecem como relevantes para a análise: condições de trabalho e de estudo, necessidade de formação, predominância do trabalho sobre o estudo, dificuldade deconciliar tempo de estudo e de trabalho. Na relação com o objeto de estudo, ressaltaremos a crise estrutural do capital, a desregulamentação das leis do trabalho e sua flexibilização e as contradições entre trabalho e estudo bem como quais possibilidades emancipatórias são visualizadas ou sonhadas pelos trabalhadores estudantes.Resume Ce travail constitue une partie de la recherche entreprise avec les étudiants du cours de pédagogie de l´Universidade de Santa Cruz do Sul – UNISC – RS – Brésil. Il est intégré dans le champ de

  13. Modelos para estimar as exigências de energia metabolizável para poedeiras

    OpenAIRE

    Sakomura,Nilva Kazue; Basaglia,Roberta; Sá-Fortes,Cristina M. L.; Fernandes,João Batista K.

    2005-01-01

    Objetivou-se, com este trabalho, elaborar um modelo para estimar as exigências de energia metabolizável (EM) para poedeiras leves da linhagem Lohmann LSL, utilizando-se o método fatorial. Para determinar o efeito da temperatura sobre as exigências de EM para mantença, foram conduzidos experimentos em câmaras climáticas com temperaturas constantes de 12, 22 e 31ºC, utilizando a técnica do abate comparativo. A exigência de energia líquida para o ganho de peso foi determinada por meio da regress...

  14. Periodistas para la era digital

    Directory of Open Access Journals (Sweden)

    Fernando Villalobos G.

    2014-12-01

    Full Text Available La formación de los periodistas del siglo XXI en la era digital se concibe como un reto y el mayor desafío. Los medios digitales demandan especialización y dominio de las nuevas tecnologías. Las universidades, principales gestores de este cambio, en la sociedad del conocimiento, requieren trabajar en la reformulación de nuevos pensum y en tres terrenos fundamentales: el perfil del egresado, el estilo pedagógico y el nuevo modo de relacionarse con el mundo exterior. Se necesita de una oferta académica referida al ciberperiodismo y a la cibercomunicación. La profesión periodística, y específicamente la formación de los comunicadores registra cambios importantes debido a las nuevas tecnologías, ahora el aula es el mundo globalizado e interconectado por la gran autopista de la información, por ello, la formación del comunicador social, demanda renovadas prácticas educativas. Las universidades deben repensar el papel que están obligadas a desempeñar, reformular los pensum académicos y ofertar la cibercomunicación y el ciberperiodismo para estar al día de las grandes transformaciones.

  15. Um tico para formar adultos

    Directory of Open Access Journals (Sweden)

    Edson Mendes de Almeida

    2017-07-01

    Full Text Available A revista Tico-Tico foi lançada em 1905, com a intenção de ensinar as crianças. Era publicada como um suplemento na revista O Malho, mas que poderia ser adquirida separadamente. Em seu interior eram encontradas histórias em quadrinhos, inicialmente decalcadas dos jornais estadunidenses e posteriormente feitas por artistas nacionais, lendas e contos, galeria de fotos dos leitores, além das seções do Dr. Sabe-tudo e das Lições do Vovô. A publicação procurou desenvolver o hábito de leitura e gosto pelo conhecimento dos pequenos, que até então não tinham uma obra voltada para eles. O período estudado do periódico (1920-1922, perfaz outro movimento singular na época, o desenvolvimento da Semana de Arte Moderna de 1922, em São Paulo.

  16. Residencia para familias - Anglet (Francia

    Directory of Open Access Journals (Sweden)

    Hébrard, J. R.

    1971-11-01

    Full Text Available This residential hotel has 806 beds, which can be increased to 1,100 by adding some double beds. Its size and colour blends well with the picturesque surrounding, known as «Chambre d'Amour». The hotel involves 120 large apartments, and 50 smaller one, as well as 25 rooms for the staff, and flats for the manager and other senior officials. There is a hall, large living room, bar, rooms for playing games, nursery, and an additional hostel with 40 flats and staff rooms. The design is of a linear, continuous style, emphasizing its horizontal extension, though contrast is provided by a higher block, housing the vertical circulation facilities.Con un total de 806 plazas hoteleras, ampliables a 1.100 (si se utilizan literas, este conjunto, por su volumen y color se integra en el pintoresco paisaje del paraje conocido por «Chambre d'Amour». Comprende: 120 apartamentos; 50 más pequeños; 25 habitaciones para empleados; los apartamentos del director, gobernanta y recepcionistas; las zonas de vida en común: hall, salón, bar, sala de juegos y guardería; un albergue con 40 apartamentos; y las dependencias de la administración. Presenta un volumen lineal y continuo, modelando una composición de ritmo horizontal predominante, a la que le imprime gran variedad el cuerpo vertical de hormigón visto que contiene las circulaciones verticales.

  17. Una red para la gente

    Directory of Open Access Journals (Sweden)

    Raúl Trejo Delarbre

    2004-02-01

    Full Text Available La próxima Cumbre Mundial de la Sociedad de la Información ha revitalizado, en numerosos países, el debate acerca de las nuevas tecnologías de la comunicación y los usos que pueden tener. Lamentablemente en México hemos estado casi del todo ajenos a esa intensa, extensa y en otras latitudes fructífera discusión. Ni los especialistas interesados en estos temas, ni la sociedad que es a la postre beneficiaria o damnificada según sea el empleo de tales tecnologías, ni los organismos del Estado a cargo de tales asuntos, han propiciado la reflexión colectiva que nos podría permitir tanto afinar las posiciones de nuestro país rumbo a la cumbre de Ginebra y Túnez como deliberar, en ese contexto, acerca de lo mucho que nos falta para tener un país auténticamente imbricado en la construcción de una auténtica Sociedad de la Información.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  19. Oxitocina: nuevas perspectivas para una droga antigua

    OpenAIRE

    Steven L. CLARK; Kathleen Rice SIMPSON; G. Eric KNOX; Thomas J. GARITE

    2010-01-01

    La oxitocina es el medicamento más comúnmente asociada con la prevención de complicaciones perinatales y recientemente fue incluida por el Instituto para la Administración Medicamentosa Segura (Institute for Safe Medication Practices - ISMP) en una pequeña lista de medicamentos “con alto grado de riesgos”, lo que puede “necesitar salvaguardas especiales para reducir el riesgo de error”. Las recomendaciones actuales para administrar este medicamento son vagas en relación a la indicación, tiemp...

  20. Middleware Cerberus usando RFID para rastreabilidade bovina

    OpenAIRE

    Silva, Márcio Roberto

    2009-01-01

    A gerência na zootecnia de precisão é cada vez mais necessária para garantia de lucros e a conquista de novos mercados os quais exigem qualidade e certificação. Nesta dissertação é abordado um sistema de rastreabilidade para o controle na bovinocultura utilizando chips RFID. Sendo que a identificação segura dos animais é a base para a rastreabilidade bovina e bubalina. Em vista as exigências do mercado consumidor o governo brasileiro instituiu o Sistema Brasileiro de Identificação e Certifica...

  1. Educación para la sostenibilidad

    Directory of Open Access Journals (Sweden)

    Educadores por la sostenibilidad

    2006-04-01

    Full Text Available La importancia dada por los expertos en sostenibilidad al papel de la educación queda reflejada en el lanzamiento mismo de la Década de la Educación para el Desarrollo Sostenible o, mejor, para un futuro sostenible (2005-2014 a cuyo impulso y desarrollo esta destinado este artículo, así como la página web que la Organización de Estados Iberoamericanos ha habilitado dentro de su portal digital, para la celebración de la Década.

  2. ¿Para que la historia?

    OpenAIRE

    Jaime Jaramillo Uribe

    1998-01-01

    Para qué sirve la historia?. ¿Puede el conocimiento del pasado darnos pautas para comprender el presente? Sobre este, como sobre tantos problemas teóricos de la historia, se han realizado largos e inacabados debates entre historiadores y filósofos. En este ensayo se acepta como eficaz la hipótesis de que conocer el origen y el desarrollo de un proceso es buen fundamento para explicarse una situación final. En el caso de la historia colombiana, se parte de la base de que al producirse la indep...

  3. Modelo de negocio para bebidas funcionales Ceiba

    OpenAIRE

    Gil Giraldo, Jhonatan; Restrepo Mesa, Juan Eduardo

    2017-01-01

    El presente documento, modelo de negocio para bebidas naturales Ceiba, es el trabajo de grado realizado por los autores con el fin de optar al título de magíster en Administración (MBA) de la Universidad EAFIT -- El cual esta soportado en los diferentes conceptos y metodologías de modelo de negocio y planes de negocio -- Por tratarse de un prototipo que busca definir los elementos estratégicos necesarios para su desarrollo, arrojó como resultado que la metodología más adecuada para ser aplica...

  4. Test para la profilaxis de la prematuridad

    OpenAIRE

    Cruz Laguna, Gladys María

    2008-01-01

    La prematuridad constituye un problema mundial de salud, la comunidad científica busca predictores para disminuir su incidencia. La investigación persiguió obtener una escala de puntuación que modele las características cervicales y permita diagnosticar la condición de riesgo de las gestantes para extender el período de gestación y lograr nacimientos al término. Se realizó un cuasiexperimento en gestantes con factores de riesgo para la prematuridad del municipio Holguín. La muestra fue confor...

  5. Um lugar para a Filosofia?

    Directory of Open Access Journals (Sweden)

    Samir Dessbesel Ferreira

    2010-01-01

    Full Text Available De que modo pode a Filosofia integrar-se às demais disciplinas da grade curricular dos cursos técnicos do IFSul? E como se insere uma disciplina como essa em instituições de ensino que têm tradicionalmente como foco o ensino tecnológico e profissionalizante, como são os Institutos Federais? Primeiramente, a Filosofia poderia contribuir na formação do profissional egresso, desenvolvendo-lhe competências relacionadas ao filosofar, em especial as relacionadas ao raciocínio abstrato e à comunicação, o que poderia vir a fazer a diferença no mercado de trabalho. Assim, os Institutos Federais ofereceriam um ensino de excelência com o objetivo de formar o técnico mais bem qualificado possível ao mercado de trabalho. Todavia, o aparelhamento técnico de nossos jovens, embora essencial para o desenvolvimento do País, não pode apresentar-se como a preocupação prioritária dos educadores, pois é fundamental considerar-se a formação integral da pessoa humana. Qual educação, afinal, queremos? E qual o papel da escola pública em nossa sociedade? O direcionamento unilateral à qualificação profissional pode levar-nos à formação de uma espécie de “superpeão”. A escola não pode ser serva do mercado. Ela tem o papel maior de agente de questionamento e transformação da sociedade. A concepção de Ensino Médio Técnico-Integrado nos parece orientar-se antes para a formação “integral” do cidadão, da pessoa em sua totalidade. O trabalho não é apenas uma relação econômica, mas também ética, política e estética. Deve ser uma forma de realização, de humanização do mundo, e não de coisificação do homem. É sempre possível pensar nossos espaços de educação formal como um compartilhar humano de sentidos, de afetos, de vivências, de posturas, de identidades. A esses espaços deverá a qualificação técnica sempre agregar-se, jamais sobrepor-se.

  6. Competencias del profesorado universitario para la interculturalidad

    OpenAIRE

    Shestakova, Nataliya; Domínguez Garrido, María Concepción; Cacheiro González, María Luz

    2016-01-01

    La presente investigación está dedicada a las competencias del profesorado universitario para la interculturalidad. Se trata de un estudio exploratorio con un enfoque mixto, cualitativo y cuantitativo, cuyo objetivo es conocer las competencias intercu

  7. Actitud Positiva: la base para la competitividad

    Directory of Open Access Journals (Sweden)

    Marco Anderson Espinoza

    2008-04-01

    Full Text Available Una estrategia empresarial enfocado en el mejoramiento continuo de la productividad para la competitividad, depende significativamente del manejo inteligente de tres variables visibles:Calidad, Entrega oportuna y Costo. No obstante, estas tres variables no suelen sersuficientes. La estrategia debe ser complementada con el manejo adecuado de variables intangibles como la Motivación y las Condiciones de Trabajo, con la aplicación de Tecnología Ambientalmente Amigable, en un marco de Actitud Positiva.A final de cuentas, la Actitud Positiva es fundamental para el recurso humano de cualquier organización, a fin de construir una plataforma sólida y estable que sirva de base para soportar un proceso sostenible de mejoramiento de la productividad, para aumentar la competitividad como estrategia empresarial exitosa.

  8. Matemática para la familia

    OpenAIRE

    Cittadino, José

    1994-01-01

    Para muchos profesores de matemáticas ha sido de primordial interés encontrar estrategias didácticas apropiadas para orientar el aprendizaje de las matemáticas escolares de los niños (as) y jóvenes de manera que las clases se conviertan en encuentros agradables y la relación matemática-aprendizaje- profesor sea la mejor.

  9. Entrenamiento de fuerza para la salud

    OpenAIRE

    Ortiz Cervera, Vicente

    1996-01-01

    Este artículo describe de manera breve y clara los efectos del entrenamiento de fuerza sobre la salud, al mismo tiempo da pautas para la realización y programación de los entrenamientos de fuerza para la salud en distintas edades. Se muestran las diferentes variables del entrenamiento de la fuerza junto con ejemplos de entrenamientos, basándose en las pautas marcadas en la revisión bibliográfica descrita.

  10. Un almuerzo para llevar saludable (Packing Smart)

    Centers for Disease Control (CDC) Podcasts

    2011-08-22

    En este podcast para niños, los chicos de Kidtastics hablan sobre almuerzos creativos para llevarse a la escuela, que ayuden a mantenerse con energía el resto del día.  Created: 8/22/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 1/3/2012.

  11. Páginas web para el aprendizaje

    Directory of Open Access Journals (Sweden)

    Isabel ÁLVAREZ

    2016-04-01

    Full Text Available Este artículo plantea la construcción de paginas web como vehículo para facilitar la integracion de las tecnologias de la informacion y la comunicacion en el aula para futuros maestros. El término Página Web Coherente enfatiza la utilización de páginas cuyo objetivo principal es promover el aprendizaje siguiendo un proceso colaborativo, una estructura integradora y un contenido educativo.

  12. Agricultura familiar para el desarrollo rural incluyente

    Directory of Open Access Journals (Sweden)

    Laksmi Reddiar Krishnamurthy

    2017-04-01

    Full Text Available Las comunidades indígenas Mayas de la península de Yucatán han practicado la antigua tradición de agricultura familiar, en particular los huertos caseros, para garantizar su seguridad alimentaria. Con el objetivo de mejorar la práctica tradicional considerando paradigmas de la ciencia moderna, por una parte, se colectaron datos para definir la complejidad estructural y diversidad funcional a partir de 20 huertos familiares en cinco comunidades: X - Maben, X - Pichil, X - Yatil, San José II y Melchor Ocampo; y por otra, se organizaron grupos de discusión para dilucidar la estrategia de gestión practicada por las comunidades nativas. Los resultados mostraron que los huertos son manejados principalmente por las mujeres. También mostraron que el propósito principal del crecimiento y mantenimiento de los huertos familiares es garantizar la producción de alimentos nutritivos durante todo el año. Y, por último que los huertos caseros también sirven para propósitos secundarios tales como la provisión de productos y servicios para la medicina tradicional. El estudio sugiere que se debe de promover e invertir en huertos caseros para mejorar las estrategias de desarrollo incluyente en ambientes socio-culturales y biofísicos similares.

  13. La carrera profesional para el profesorado

    Directory of Open Access Journals (Sweden)

    José Gimeno Sacristán

    2010-01-01

    Full Text Available La carrera del profesorado es un instrumento para el reconocimiento del mérito de los profesores en el desarrollo de su profesionalidad -lo cual supone atender a la mejora de sus capacidades cognitivas como a su competencia reflexivo-práctica- cuyos fines son la motivación para el ejercicio de sus funciones, reforzar su compromiso con la educación en general y como forma de reconocer con justicia el mérito de los mejores profesionales. Desde un punto de vista estrictamente educativo, la carrera debe servir para la mejora de las prácticas de enseñanza que incidan en la mejora de los aprendizajes. Esta pretensión nos exige explicitar los criterios para determinar lo que entendemos como buenas prácticas y precisar los criterios para su evaluación. La complejidad de la enseñanza requiere metodologías adecuadas para abordar procesos de índole cualitativa. La regulación de la carrera docente tiene que superar tanto el cuantitativismo fácil en los métodos y la regulación burocrática de niveles de calidad, así como contemplar un conjunto de incentivos no solamente salariales.

  14. Amendoins silvestres para uso ornamental.

    Directory of Open Access Journals (Sweden)

    Renato Ferraz de Arruda Veiga

    2003-06-01

    Full Text Available Algumas espécies silvestres de amendoim (Arachis spp. gênero Arachis L. (Fabaceae, vêm sendo utilizadas como forração em jardins no Brasil, porém todas com pouca variabilidade já que a distribuição do germoplasma é feita sempre pelos mesmos acessos4. Por outro lado, inúmeras coletas têm sido realizadas, particularmente pela Embrapa Recursos Genéticos e Biotecnologia (Cenargen, disponibilizando acessos até então inacessíveis à pesquisa científica. Em virtude dessa nova disponibilidade e igualmente de híbridos resultantes de pesquisas do Cenargen, organizou-se este trabalho. Foram objeto desta pesquisa cinco espécies: A. glabrata Benth., A. helodes Mart. ex Krapov.& Rigoni, A. pintoi‘Krapov.& W.C.Gregory, A. repens Handro e A. kempff-mercadoi Krapov.,W.C.Gregory & C.E.Simpson, e seis híbridos originados dos paternais: A. appressipila Krapov.&W.C.Gregory, A. paraguariensis Chodat & Hassl., A. pintoi, A. repens e A. vallsi Krapov.& W.C.Gregoryi. O experimento foi desenvolvido no período dos anos agrícolas de 1998 a 2000, na Fazenda Santa Elisa do Instituto Agronômico (IAC, em Campinas (SP, anotando-se o número de flores por planta, a velocidade de desenvolvimento, a capacidade de cobertura do solo, aspectos ornamentais como exuberância das flores e folíolos, coloração e, ainda, sanidade e vigor dos acessos. Os híbridos apresentaram um bom comportamento, porém com ciclo anual, ao passo que os acessos de Arachis kempffmercadoi, A.helodes, A. repens e A. glabrata mostraram-se mais recomendáveis para o uso em jardins por serem perenes. Todos os acessos ficam mais bonitos no verão em razão do período de floração e graças ao verde de sua massa foliar.

  15. Estrategia para elevar la motivación laboral; factor imprescindible para mejorar nuestra productividad.

    OpenAIRE

    Reina de los Ángeles Carballé Piñón

    2015-01-01

    Este trabajo "Estrategia para elevar la motivación laboral; factor imprescindible para mejorar nuestra productividad" resulta de la investigación realizada para tesis de maestría; se realizó el estudio de 2 entidades, nos permitió conocer las principales posiciones que sobre motivación existen, factores que la influencian, cómo incide en el desempeño laboral y que acciones diseñar para elevarla. Las 2 entidades seleccionadas, claves en el desempeño empresarial son un centro de interfase y un...

  16. Alimentos balanceados para perros en Costa Rica

    Directory of Open Access Journals (Sweden)

    Ruth Vargas

    2001-01-01

    Full Text Available Diagnóstico de la comercialización de alimentos balanceados para perros en Costa Rica. Para ampliar los reportes oficiales de la comercialización de alimentos para perros se creó una base de datos que incluyó cantidad, costo, empaque y formulación durante el período 1998 a agosto del 2000. De 1995 a 1998 y de 1996 a 1999 la producción nacional incrementó un 90,4% y la importación un 42,56% respectivamente, ocupando los alimentos nacionales un 72% del tonelaje y un 70% del valor en dólares americanos. No fue posible determinar cuál es el empaque más comercializado, pero si que los alimentos extrusados son los que ocupan el primer lugar y que los alimentos recomendados para cachorros y adultos son los que más se comercializan. La ausencia de datos en las declaraciones sugiere la necesidad de incrementar el control en las mismas en caso de requerirse un estudio de mercado, ya que contrariamente a esta situación el mayor número de garantías inscritas corresponden separadamente para las fases de cachorros y adultos. Merece también atención que las garantías indican mayores porcentajes de proteína cruda que los recomendados por la AAFCO y que al menos 36 fórmulas son recomendadas para estados sanitarios específicos (p.e. para perros con problemas de alergias, cálculos renales, pérdidas de pelo, etc. sin que oficialmente se encuentre registrada ninguna fórmula medicada

  17. Cross-elicitation responses to 2-methoxymethyl-para-phenylenediamine in para-phenylenediamine-allergic individuals

    NARCIS (Netherlands)

    Schuttelaar, M.-L.; Coenraads, P.-J.; Blömeke, B.; Goebel, C.

    2016-01-01

    The introduction of a methoxymethyl side chain into para-phenylenediamine (PPD) resulted in the development of a new hair dye molecule: 2-methoxymethyl-para-phenylenediamine (Me-PPD). Besides having excellent hair colouring properties, this PPD derivate has significantly lower skin-sensitizing

  18. Biocomercio: una alternativa para el desarrollo sostenible

    Directory of Open Access Journals (Sweden)

    Carlos Murillo R.

    2008-01-01

    Full Text Available El desarrollo sostenible en países ricos en biodiversidad dependerá de la capacidad de los gobiernos de implementar los arreglos institucionales necesarios para conciliar la preservación de los recursos naturales con el uso de los mismos para la producción de bienes y servicios que puedan potenciar el crecimiento económico y un mayor bienestar para las comunidades locales donde estos recursos se encuentren. Este es el objetivo de la Iniciativa de Biocomercio que ha venido impulsando la Conferencia de Naciones Unidas para el Comercio y el Desarrollo (UNCTAD en distintos países de Latinoamérica. En el tanto estos principios y los establecidos en el CDB se puedan viabilizar e inspiren los distintos Programas Nacionales de Biocomercio en los países de la región, parecería no haber dudas de que la Iniciativa abre nuevas puertas para el uso, aprovechamiento y desarrollo sostenible de los mismos.

  19. Motivacao para o tratamento. Dados psicometricos da escala SOCRATES 8D e estrategias psicoterapeuticas para motivar para o tratamento

    OpenAIRE

    Janeiro, Luís; Faísca, Luís

    2008-01-01

    A motivação para o tratamento é considerada um factor fundamental para o processo de mudança e tratamento do toxicodependente. Prochaska, Diclemente, e Norcross (1992) consideram que a motivação que o sujeito possui no início do tratamento determina directamente os resultados alcançados no mesmo. Diclemente, Bellino, e Neavins (1999) acrescentam, ainda, que a estreita relação entre os resultados obtidos no tratamento e a motivação aquando do seu início pode ser medida pela formação precoce de...

  20. Nuevo lenguaje para un nuevo medio

    Directory of Open Access Journals (Sweden)

    Inma Martín Herrera

    2014-12-01

    Full Text Available El concepto tradicional de comunicación unidereccional se ha roto para convertirse en comunicación pluridireccional que permitirá la retroalimentación informativa. Las nuevas formas de redactar, contar diseñar y presentar la información en Internet exige nuevos hábitos de lectura por parte de la audiencia. El lector deberá tomar conciencia de que está frente a un medio diferente con el que debe familiarizarse para hacer uso correcto del soporte digital, se informará adecuadamente para disfrutar de las ventajas del innovador medio, conocido como Periodismo de servicios o Nuevo Periodismo.

  1. Rutina AUTOLISP para el despiece de columnas

    Directory of Open Access Journals (Sweden)

    Lorena Cocunubo Carreño

    2014-06-01

    Full Text Available El proyecto de creación de una herramienta Autolisp para el dibujo automático de los despieces de vigas sometidas a flexión y a cortante se desarrolla en un ambiente de programación informática LISP. Se inicia con la programación en el Visual Lisp de AutoCAD del algoritmo que permite tomar información de anchos de luz, sección transversal y momentos resistentes la viga para que automáticamente ejecute los comandos y el resultado final sea un despiece detallado de los hierros por flexión junto con los estribos por cortante separados adecuadamente. Los resultados están sujetos a criterios de diseños de la NSR-10 para así garantizar la seguridad del diseño sísmico.

  2. Libertad religiosa, camino para la paz

    Directory of Open Access Journals (Sweden)

    Antonio Alonso

    2011-01-01

    Full Text Available La libertad religiosa es el núcleo del Mensaje para la XLIV Jornada Mundial de la Paz que ha dirigido Benedicto XVI. Cuestión, sin duda, extraordinariamente delicada, pues comporta graves implicaciones en materia de seguridad principalmente por dos motivos: primero, porque su violación supone una injusticia difícil de compaginar con el respeto a los Derechos Humanos; segundo, porque dicha libertad no puede ser esgrimida como pretexto para atropellar los derechos de los demás conciudadanos o incluso socavar la propia seguridad del Estado. El Santo Padre denuncia, a su vez, los estragos del relativismo y de los fanatismos, tanto religioso como anti-religioso, y propone el ejercicio del diálogo basado en la razón para superar los obstáculos en la convivencia interpuestos por estas amenazas a la paz y la seguridad.

  3. Oxitocina: nuevas perspectivas para una droga antigua

    Directory of Open Access Journals (Sweden)

    Steven L. CLARK

    2010-12-01

    Full Text Available La oxitocina es el medicamento más comúnmente asociada con la prevención de complicaciones perinatales y recientemente fue incluida por el Instituto para la Administración Medicamentosa Segura (Institute for Safe Medication Practices - ISMP en una pequeña lista de medicamentos “con alto grado de riesgos”, lo que puede “necesitar salvaguardas especiales para reducir el riesgo de error”. Las recomendaciones actuales para administrar este medicamento son vagas en relación a la indicación, tiempo de uso, dosis y el monitoreo de los efectos maternos y fetales. Una revisión de los datos clínicos y farmacológicos disponibles sugiere que las orientaciones específicas y basadas en evidencias para administrar oxitocina durante el parto puede derivarse de datos disponibles. Si implementadas, estas prácticas pueden reducir la probabilidad de daños al paciente. Esto sugiere el foco de las orientaciones para la administración electiva limitada de oxitocina, considerar estrategias que disminuyan la necesidad de usar oxitocina, confiar en terapéuticas de bajas dosis de oxitocina, la adhesión a definiciones semicuantitativas específicas sobre parto adecuado e inadecuado, y la aceptación de que, una vez que la actividad uterina adecuada sea alcanzada, es generalmente preferible esperar más tiempo que aumentar la infusión de oxitocina. El uso de protocolos conservadores y específicos para monitorear los efectos de la oxitocina en la madre y en el bebé tiende no sólo a aumentar los resultados, mas también a reducir los conflictos entre miembros del equipo obstétrico. Implementar estas orientaciones parece ser apropiada en una cultura cada vez más focalizada en la seguridad del paciente.

  4. Estrategias de mercado para el frijol centroamericano

    Directory of Open Access Journals (Sweden)

    Lourdes Mart\\u00EDnez

    2004-01-01

    Full Text Available Estrategias de mercado para el frijol centroamericano. En los últimos años, el sub-sector de frijol en Centro América ha sido testigo de varios cambios dinámicos. Si no se encuentran medidas para incrementar la competitividad regional de este sub-sector, los países centroamericanos experimentarán impactos negativos en las áreas sociales y económicas de considerable magnitud, especialmente ahora que Centro América necesita ajustar su economía a los nuevos requerimientos de mercados mas abiertos, como el Tratado Centroamericano de Libre Comercio con USA (TLC. Vendedores de frijoles a nivel intermediario y de consumo final, así como técnicos de oficinas gubernamentales dedicadas al mercadeo de frijoles en Centro América fueron entrevistados para documentar los cambios experimentados, identificar los obstáculos que frenan la viabilidad del sub-sector e identificar las oportunidades de incremento de mercados en el futuro para los productores y vendedores de frijol. Los resultados muestran que para que continúen siendo competitivos, los países centroamericanos deben incrementar la productividad a través del apoyo a las investigaciones para el mejoramiento de variedades de frijol, especialmente aquellas que los consumidores prefieren por características específicas (e.g. color. También es imprescindible el fortalecimiento de los programas de distribución de variedades mejoradas a los productores; las mejoras en la transmisión de información de mercado a los productores; el fortalecimiento de los contactos entre productores, comercializadores a nivel mayorista y supermercados; y una política más específica de apertura de mercados de exportación, especialmente con los Estados Unidos.

  5. Algoritmos para problemas de corte e empacotamento

    OpenAIRE

    Thiago Alves de Queiroz

    2010-01-01

    Resumo: Problemas de Corte e Empacotamento são, em sua maioria, NP-difíceis e não existem algoritmos exatos de tempo polinomial para tais se for considerado P ¿ NP. Aplicações práticas envolvendo estes problemas incluem a alocação de recursos para computadores; o corte de chapas de ferro, de madeira, de vidro, de alumínio, peças em couro, etc.; a estocagem de objetos; e, o carregamento de objetos dentro de contêineres ou caminhões-baú. Nesta tese investigamos problemas de Corte e Empacotament...

  6. Desarrollo de aplicaciones para Windows Phone

    OpenAIRE

    Castellanos de la Torre, Francisco José

    2013-01-01

    Desarrollar una aplicación para dispositivos móviles no es una tarea sencilla, ya que precisamos no solo tener conocimientos de programación, sino que también tenemos que familiarizarnos muy bien con el entorno de desarrollo y el sistema operativo para el cual pretendemos crear la aplicación. Esto consiste en conocer en profundidad tanto las características técnicas de los dispositivos como las distintas APIs que tenemos a nuestra disposición. Hemos elegido Windows Phone 7.5 porque ha sido...

  7. Imaging of limbic para-neoplastic encephalitis

    International Nuclear Information System (INIS)

    Rimmelin, A.; Sellat, F.; Morand, G.; Quoix, E.; Clouet, P.L.; Dietemann, J.L.

    1997-01-01

    Para-neoplastic limbic encephalitis is a rare syndrome mostly associated with small cell lung cancer. We present the case of a 69-year-old man with selective amnesia suggesting limbic encephalitis. A neuroendocrine cell lung cancer was found, confirming the diagnostics of para-neoplastic limbic encephalitis. Contrast-enhanced cerebral CT was normal whether magnetic resonance imaging showed signal abnormalities of the medial part of temporal lobes and hippocampal regions. Because neurologic improvement may follow treatment of the primary tumor, early diagnosis is important. (authors)

  8. Compilador para lenguaje basado en continuaciones

    OpenAIRE

    Ramos Carreño, Carlos

    2015-01-01

    Las continuaciones son una construcción de algunos lenguajes de programación a partir de las cuales pueden elaborarse elementos más complejos, como fibras, generadores, excepciones y corrutinas. Sin embargo, hay poco soporte nativo para ellas en los lenguajes más populares, como por ejemplo Java. En este trabajo se estudia este concepto en profundidad, centrándonos en las llamadas “continuaciones delimitadas”. Para ello se ha implementado un lenguaje de bajo nivel con soport...

  9. Vivienda sostenible para un consumo casi nulo

    OpenAIRE

    MENDOZA GÓMEZ, CLAUDIA MARÍA

    2014-01-01

    Este TFG pretende aplicar los conceptos de eficiencia energética y sostenibilidad en la edificación para conseguir una vivienda con un consumo casi nulo. Para ello, es necesario reducir la demanda y los consumos así como las emisiones de CO2, contribuyendo de esa forma a cuidar el medio ambiente, a reducir los gases de efecto invernadero y la huella de carbono de la vivienda. El propósito es conseguir una vivienda sostenible que aproveche todo el potencial de las energías renovables y, ello i...

  10. Taller para padres en Centro CAES

    OpenAIRE

    Beltrán Franch, Enrique

    2015-01-01

    Treball final de Grau en Mestre o Mestra d'Educació Infantil. Codi: MI1040. Curs acadèmic 2014-2015 Este trabajo versa sobre las distintas fases que se han llevado a cabo para la realización en la realización de un taller para padres, organizado en seis sesiones, tratando diferentes temas (centrados en la diada de relación padres hijos y en proceso de socialización que en ella se lleva) en cada sesión. La finalidad de este trabajo era tanto concienciar a los padres en la gran r...

  11. Gobierno de las TI para universidades

    OpenAIRE

    Fernández Martínez, Antonio; Llorens Largo, Faraón

    2011-01-01

    Entre los objetivos de esta publicación están el establecer la importancia del gobierno de las TI, describir sus fundamentos y presentar las herramientas disponibles para implementarlo en una organización. Se presenta con detalle la norma ISO 38500, COBIT y el modelo GTI4U, que se ha desarrollado para ser utilizado en el ámbito universitario. Cabe destacar que incluye una descripción detallada de cómo implementar el gobierno de las TI en una universidad. La CRUE pretende que estos conten...

  12. El centro del mundo para los gallegos

    OpenAIRE

    Mandianes Castro, Manuel

    1982-01-01

    Estudio sobre la noción de espacio en Galicia. Se pretende demostrar que para los gallegos el universo tiene un centro, con diferentes niveles de aprehensión, alrededor del cual se organiza la comunidad. Para este trabajo se han realizado encuestas entre los habitantes de la región de la Limia (Orense) y los de Loureses. El trabajo se divide en tres apartados atendiendo a los distintos niveles de percepción del centro del mundo: "lareira" (hogar), "encrucillada" (encrucijada) y cementerio.

  13. FOTOBIORREACTOR: HERRAMIENTA PARA CULTIVO DE CIANOBACTERIAS

    Directory of Open Access Journals (Sweden)

    Luis Guillermo Ramírez Mérida

    2014-05-01

    Full Text Available Las cianobactérias son organismos eficientes en la conversión de energía solar y producen una gran variedad de metabolitos. En la actualidad son el centro de atención para la producción de biocombustible, son usadas como biofertilizantes, control de contaminación ambiental y como fuente de nutrientes en alimentación humana y animal. Con el fin de proporcionar crecimiento y aprovechar el potencial de las cianobacterias, se requieren fotobiorreactores eficientes. Aunque se han propuesto muchos tipos de fotobiorreactores, no existe un reactor ideal, solo unos pocos pueden utilizarse para la producción de biomasa de cianobacterias. De hecho, la elección del fotobiorreactor más adecuado depende de la situación, ya que tanto las especies de algas disponibles y el destino final jugarán un papel importante. Uno de los principales factores que limita su aplicación práctica en cultivos de biomasa es la transferencia de masa. Por esto, entender el coeficiente de transferencia de masa en los fotobiorreactores es necesario para una operación eficiente del cultivo de biomasa en cianobacterias. En esta revisión, se discuten varios tipos de fotobiorreactores muy promisorios para la producción de biomasa de cianobacterias.

  14. Para uma abordagem virtuosa do Jornalismo

    Directory of Open Access Journals (Sweden)

    Rogério Christofoletti

    2012-06-01

    Full Text Available As últimas décadas têm favorecido o crescimento do interesse e dos estudos sobre a ética jornalística. No Brasil e em outras praças, as abordagens deste tema têm sido na maioria das vezes por um caráter deontológico ou utilitarista. Neste artigo, chamamos a atenção para uma perspectiva que privilegie as virtudes como pontos de partida para os debates acerca das condutas dos profissionais. Uma ética das virtudes remete a Aristóteles e aos estoicos, mas vem sendo retomada por autores mais contemporâneos, como Macintyre e Comte-Sponville, entre outros. No jornalismo, esta abordagem não é definitiva ou totalizante, mas contribui para uma compreensão mais ampla da discussão, chamando inclusive a atenção para recomendações éticas úteis, práticas e atuais.

  15. ESPIRITUALIDADE PARA OUTRO MUNDO POSSÍVEL

    Directory of Open Access Journals (Sweden)

    Agenor Brighent

    2007-01-01

    Full Text Available Teve lugar, em Nairobi, o II Fórum Mundial de Teologia e Libertação, entre os dias 16e 19de janeiro de 2007.O primeiro havia sido realizado em Porto Alegre, em janeiro de 2005, cujos resultados estão publicados em L.C. SUSIN (org., Teologia para outro mundo possível, São Paulo: Paulinas, 2006 (485 pp.. O segundo teve como tema - "espiritualidade para outro mundo possível". Fizeram-se presentes 300participantes, oriundos dos cinco Continentes, em sua maioria da África, especialmente de Nairobi, seguida da Europa, América, Ásia e Oceania, respectivamente. Para além da reflexão e dos conteúdos, o simples encontro e cruzamento de buscas e realizações em esfera planetária, já justifica por si só o evento. Em tempos de crise de paradigmas e dos metarrelatos, a experiência se erige como lugar privilegiado para repensar a razão e as razões do existir, do mundo e da fé. Os trabalhos tiveram lugar no Carmelite Center, nos arredores da contrastante capital do Quênia.

  16. Premissas para o Ensino Superior do Design

    Directory of Open Access Journals (Sweden)

    André Luis Marques da Silveira

    2016-12-01

    Full Text Available Este artigo aborda a temática da Educação Superior e objetivo identificar premissas para o Ensino em Design no Brasil. Para tanto, efetua um estudo dos conteúdos das comunicações da área em periódicos e livros quanto ao assunto. O método de investigação utilizado foi a análise de conteúdo e observou as seguintes etapas de investigação: registro de dados, interpretação inferencial e categorização. Num primeiro momento, identifica a frequência do aparecimento de índices lexicais quanto ao relato de problemas no processo de Ensino-aprendizagem do Design e as proposições para o seu enfrentamento. Procede uma interpretação inferencial destes dados e, por fim, propõe como resultado, um conjunto de doze premissas que devem ser observadas quanto ao Ensino Superior em Design, a saber: 1 Incentivar o empreendedorismo; 2 Nivelar a Formação; 3 Desenvolver estrategistas; 4 Pensar a ética na atuação profissional; 5 Educar para o social; 6 Valorizar os ideias humanistas; 7 Repensar as estruturas acadêmicas; 8 Focar na aprendizagem baseada em problemas; 9 Aceitar os novos paradigmas; 10 Fomentar o pensamento crítico reflexivo; 11 Estimular a transdisciplinaridade; 12 Focar nas economias emergentes.

  17. Construcciones de madera compuestas para cerramientos autoportantes

    OpenAIRE

    Saleh Pascha,Khaled

    2013-01-01

    El entendimiento de la construcción como un ejercicio articulador de piezas y materiales recorre el argumento de este artículo, que presenta desarrollos de componentes constructivos que mezclan madera con hormigón o vidrio, para envolventes horizontales y verticales.

  18. A study of Para-Sasakian manifold

    International Nuclear Information System (INIS)

    Rahman, M.S.

    1995-08-01

    A Para-Sasakian manifold M is viewed in the light of an almost paracontact manifold. The fundamental concepts of M in spirit to Recurrent, Ricci-recurrent, 2-Recurrent and 2-Ricci-recurrent manifolds are presented. An η-Einstein manifold modelled on P-Sasakian manifold is then treated with simplified proofs of some results. (author). 7 refs

  19. Edificio para oficinas en Hartford, Estados Unidos

    Directory of Open Access Journals (Sweden)

    Sherwood, Mills y Smith, Arquitectos

    1961-05-01

    Full Text Available Este edificio ha obtenido el primer premio del Instituto Americano de Arquitectos, en 1960, y el Certificado de Mérito para un proyecto destacado, en 1959, de la Asociación de Arquitectos de Nueva York.

  20. Un TIM verde para el POT

    OpenAIRE

    Duque Escobar, Gonzalo

    2014-01-01

    Manizales, que tampoco escapa a los problemas causados por la proliferación de carros y motos, y la congestión vehicular, debe integrar dos objetivos al POT: más transporte público colectivo y masivo, y mas ciclovías y rutas peatonales para viajes no motorizados

  1. Estudio sobre un bordillo encauzador para carretera

    Directory of Open Access Journals (Sweden)

    Rocci, Sandro

    1961-10-01

    Full Text Available La utilidad de un bordillo prefabricado resulta bien evidente. Puede cumplir las funciones de: limitador lateral del firme, fácil reposición, evitar el deterioro de los márgenes, y, convenientemente dispuesto, constituir un eficaz balizamiento nocturno de la carretera. Puede, ademáa, utilizarse como encofrado para construir la banda exterior del firme.

  2. Educación para la paz

    Directory of Open Access Journals (Sweden)

    Federico Mayor Zaragoza

    2003-01-01

    Full Text Available La educación para la paz ha experimentado un desarrollo importante en los últimos 20 años, y el 2000 ha sido declarado Año Internacional para la Cultura de Paz. Exige un esfuerzo de pariicipación y una capacidad crítica para facilitar el paso de una cultura de guerra a un cultura de paz. Se trata de ayudar a todos los ciudadanos a observar y reflexionar sobre el conjunto de la tierra y de quienes la habitan. De escuchar a los jóvenes y ser escuchado. La educación para la paz ha de ser considerada como contenido transversal de la educación. La situación actual, los conflictos interétnicos e interculturales , la exclusión y la marginalidad, las sociedades pobres y las ricas son cuestiones que reclaman una educación par la paz. De la cultura de imposición hemos de pasar a la cultura del diálogo y parti-cipación, solidaridad, compromiso, tolerancia y respeto. Es necesario construir otro mundo en el que podamos asegurar a nuestros descendientes el futuro. La paz es un comportamiento, es traducir a la práctica los principios de con-vivencia, de solidaridad, de fraternidad. Sólo así «vendrá el amanecer (y brilla-rá mucha luz en nuestro camino»

  3. Retos para la agricultura en Costa Rica

    Directory of Open Access Journals (Sweden)

    Oscar Arias M.

    2005-01-01

    Full Text Available Retos para la agricultura en Costa Rica es un análisis crítico del desarrollo agrícola de Costa Rica de los últimos 25 años. La diversificación agrícola que promovió Costa Rica en la década de los ochenta, permitió ampliar la oferta exportable y reducir la vulnerabilidad de la dependencia económica de productos tradicionales, como café y banano. Los retos de la economía global y el establecimiento de tratados comerciales con muchos países, hacen necesario que el país promueva en el sector agrícola la exportación con mayor valor agregado, para lo cual es necesario una modernización y reconversión productiva, ya que el modelo actual está agotado. Debemos mejorar sustancialmente los bienes y servicios que ofrecemos; para este propósito, algunos aspectos como la imagen de marca del país con tradición democrática, respeto a los derechos laborales, así como las buenas prácticas de manejo ambiental, deben publicitarse. Como una herramienta clave para la incorporación de mayor valor agregado a nuestra producción agrícola, debemos promover la inversión en investigación y desarrollo, que históricamente ha sido escasa (0,4% del PIB. En vista de que el Estado Costarricense ha demostrado una incapacidad crónica para impulsar la ciencia y la tecnología como una herramienta para nuestro desarrollo, se propone un estímulo a la inversión privada y el fortalecimiento de una alianza con el Estado y las universidades. Se analiza la conveniencia del fortalecimiento de la autosuficiencia alimentaria y de que las empresas pequeñas y medianas jueguen un papel más activo en la agro-exportación. Respecto a los tratados comerciales que se han venido negociando, se considera la conveniencia para el país, ya que son instrumentos para integrar nuestro quehacer económico a nivel mundial, y nuestro deber es el de luchar para que el sector agropecuario tenga oportunidad de subsistir competitivamente según esas nuevas reglas y

  4. Modelos para estimar consumo e exigências nutricionais para poedeiras comerciais

    OpenAIRE

    Palma Bendezu, Hilda Cristina [UNESP

    2016-01-01

    O objetivo deste trabalho foi elaborar um modelo para calcular as ingestões de aminoácidos e energia para a fase de maturação sexual e produção de ovos. As exigências de energia, aminoácidos e consumo de ração foram calculados pelo método fatorial, considerando na fase de maturação sexual a quantidade de nutrientes requerida para mantença e a quantidade de nutrientes necessários para crescimento e deposição de nutrientes corporais em cada componente do corpo (ovário, oviduto, corpo livre de ...

  5. Significados da gravidez e da maternidade: discursos de primíparas e multíparas

    OpenAIRE

    Silva, Flavia Baroni; Souza, Laura Vilela e; Scorsolini-Comin, Fabio

    2013-01-01

    Resumo: O objetivo foi compreender os sentidos sobre maternidade e as vivências da gravidez em gestantes primíparas e multíparas. Foram entrevistadas seis gestantes, sendo três primíparas e três multíparas. Nas falas, foram trazidos temas como dificuldades físicas, alterações corporais, repercussão da gravidez no relacionamento conjugal, planejamento da gravidez e envolvimento paterno. Observou-se, nas primíparas, que a inexperiência trouxe insegurança, ao passo que, em algumas multíparas, ho...

  6. Biofunctionality and immunocompatibility of starch-based biomaterials

    Science.gov (United States)

    Marques, Alexandra Margarida Pinto

    A procura de novos biomateriais que desempenhem funcoes especificas sem, no entanto, desencadearem respostas negativas nos hospedeiros constitui um desafio permanente e actual nesta area. Biomateriais degradaveis foram uma das solucoes propostas e actualmente em aplicacao mas, embora possuam vantagens inegaveis, tambem apresentam alguns problemas nomeadamente no que diz respeito aos seus produtos de degradacao e respectivos efeitos negativos consequentes. Outros biomateriais, entre os quais polimeros de origem natural, foram propostos considerando que os seus produtos de degradacao poderao ser incorporados nas vias metabolicas normais evitando efeitos secundarios no hospedeiro. Ate ao momento, e apesar de todos os esforcos e do grande numero de dispositivos biomedicos desenvolvidos, o biomaterial ideal para uma aplicacao especifica ainda nao foi encontrado. Estudos com polimeros biodegradaveis a base de amido demonstraram que estes materiais possuem propriedades promissoras abrindo novas perspectivas para a sua possivel aplicacao numa variedade de aplicacoes biomedicas. Assim, de modo a demonstrar que estes materiais tem de facto potencial para serem utilizados em, por exemplo, substituicao ossea, sistemas de libertacao controlada, cimentos osseos e engenharia de tecidos, seria imperativo avaliar com maior profundidade a resposta biologica desencadeada pelos mesmos. Para tal foi delineado um plano de trabalhos com tres objectivos principais: i) avaliar a citocompatibilidade dos polimeros e compositos a base de amido com monitorizacao da citotoxicidade e analise da adesao e proliferacao celulares nas suas superficies. Foi dada particular atencao a osteoblastos considerando uma possivel aplicacao ortopedica para estes materiais; ii) estabelecer modelos in vitro para analisar e prever, tanto quanto possivel, uma situacao real de resposta inflamatoria; iii) validar os resultados in vitro com um modelo in vivo ja estabelecido em outros trabalhos de analise da resposta

  7. Plan de mercadeo para una promotora de eventos corporativos

    OpenAIRE

    Burbano Zhindon, Andrea Cristina; Chavez Lopez, Maria Cecilia; Orlando Haro, Sofia Pierina; Miranda, Jorge Luis

    2009-01-01

    Este proyecto presenta una alternativa para todas aquellas empresas que realizan eventos frecuentemente, ofreciéndoles un servicio personalizado para la coordinación de cada uno de los detalles que conlleva la organización de un evento. El objetivo fundamental de este estudio es desarrollar un plan de mercadeo para el servicio antes mencionado, aplicando los principios del marketing para su correcta implementación.

  8. Sistema ultra-sonico para medida volumetrica

    OpenAIRE

    Isaias Ferreira da Silva

    1999-01-01

    Resumo: Um método inovador para a medida do volume de um líquido dentro de um recipiente fechado é proposto. A motivação deste trabalho é a aplicação do método para a medida do volume de combustível dentro de um tanque de automóvel. Este método se baseia no fenômeno de reverberação sonora que relaciona o tempo de decaimento da intensidade do som dentro de um ambiente com o seu volume. Este tempo, conhecido como tempo de reverberação, está associado ao volume vazio dentro do recipiente, ao mat...

  9. Novos tempos para nossa jovem Tempus

    Directory of Open Access Journals (Sweden)

    Ana Valéria Machado MENDONÇA

    2014-12-01

    Full Text Available A Revista Tempus Actas em Saúde Coletiva chega ao final de 2014 com muitos motivos para comemorar, muitas foram as vitórias, entre elas, o lançamento dos seus dois últimos números do ano. Ao lançarmos os Números 3 e 4, o primeiro nesta semana e o segundo na próxima, trazemos uma nova formatação visual, normativa e editorial, segundo as exigências da base de dados LILACS - Literatura Latino-Americana e do Caribe em Ciências da Saúde, um dos mais expressivosindexadoresda América Latina e Caribe.Isso mesmo, fomos avaliados positivamente e estamos a um passo de mais uma importante indexação para nosso periódico científico.

  10. Technological properties of kaolin from Para

    International Nuclear Information System (INIS)

    Hildebrando, E.; Martin-Cortes, G.R.; Esper, F.J.; Wiebeck, H.; Alves Junior, P.; Valenzuela-Diaz, F.R.

    2011-01-01

    The NE of the State of Para, is notable for its large reserves of kaolin for paper. Kaolin is a mineral composed of hydrated aluminum silicates such as kaolinite and halloysite. The exploitation of these reserves to generate products with higher commercial value, especially in the industries of adsorbents and catalysts, is what motivates the continuous study of technological properties of the Amazon kaolin's. Thus, this paper presents a technological characterization of a sample of kaolin from Para State by X-ray diffraction, SEM - scanning electron microscopy and infrared spectroscopy. The results of preliminary tests indicate that the sample consists for the most part by kaolinite present in low concentrations of quartz and anatase. (author)

  11. Un mundo empresarial para el bachiller

    Directory of Open Access Journals (Sweden)

    Melquicedec Lozano Posso

    2015-04-01

    Full Text Available RESUMEN Ante las dificultades a que se ve enfrentado el bachiller colombiano, existen alternativas que es necesario estudiar e implementar a la mayor brevedad, con el ánimo de reducir los conflictos que se derivan, cuando los cupos en las universidades son cada vez más reducidos frente a la demanda. Las políticas educativas deben estar en consonancia con el desarrollo empresarial Hoy no es recomendable desde ningún punto de vista, económico, político y social, preparar para el empleo. Desde la primaria al bachillerato se debe inculcar en el  niño y en el joven la necesidad imperante de educarse para generar trabajo independientemente y productivo.

  12. Rius para principiantes, recepción

    Directory of Open Access Journals (Sweden)

    Mario Kaplún

    2015-01-01

    Full Text Available ¿En qué se basa la complicidad entre el medio y sus usuarios? Ni la imposición externa, ni la gratificación de los programas explican por qué las audiencias prestan su consenso legitimando en parte la mediocridad. Para el autor la explicación requiere contextualizar la recepción y analizar los "modos de uso" de los medios. Por ese camino no descubrimos el funcionamiento del principio del placer sino un síntoma más de la trágica desarticulación social. Intenta proponer dos pautas teóricas y metodológicas para el estudio de la recepción masiva. Un abordaje de esa naturaleza implica la exploración de los condicionamientos sociales de la recepción que desarrolla a continuación.

  13. Material instruccional como recurso para escuelas unidocentes

    Directory of Open Access Journals (Sweden)

    Irma Encinas Ramírez

    1992-11-01

    Full Text Available En el 11 Seminario sobre "Análisis y Perspectivas de la Educación en el Perú" (1985, organizado por el Centro de Investigaciones y Servicios Educativos (CISE-PUC, en la Comisión Educación Rural se analizaron y discutieron los aspectos más relevantes de la amplia problemática de este sector. En tal sentido los problemas referentes a las escuelas unidocentes dieron margen a que un grupo de estudiantes de nuestra Facultad se interesara en ahondar su estudio para ofrecer las respuestas y alternativas más convenientes. Consideramos que este trabajo es significativo y de actualidad, pues hasta el presente, los profesores de centros unidocentes carecen decapacitación específica, de orientaciones, medios y recursos didácticos para hacer frente a su difícil labor.

  14. Implementation of a computational system at the Center for Nuclear Technology Development, for systematization the application of the FMEA - Failure Mode and Effects Analysis, for identification of dangerous and developed risks evaluation; Implementacao de um sistema computacional no Centro de Desenvolvimento da Tecnologia Nuclear para sistemarizar a aplicacao da tecnica FMEA - Failure Mode and Effects Analysis - na identificacao de perigos e avaliacao de riscos desenvolvida

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Danyel Pontelo; Vasconcelos, Vanderley de, E-mail: dpc@cdtn.b, E-mail: vasconv@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2009-07-01

    The regulatory bodies request risks evaluations for nuclear and radioactive licensing purposes. In Brazil those evaluations are contained by the safety analysis reports requested by the Brazilian Nuclear Energy Commission (CNEN), and risk analysis studies requested by the environment organisms. A risk evaluation includes the identification of the risks and the accident sequence which can occur, and the estimation of the frequency and his undesirable effects on the industrial installations, the public, and the environment. The identification and the risk analysis are particularly important for the implementation of a health, environment and safety integrated management according to the regulation instruments ISO 14001, BS 8800 and OHSAS 18001. The utilization of the risk identification techniques and the risk analysis is performed at the non nuclear industry, in a non standard form by the various sectors of an enterprise, diminishing the effectiveness of the recommended actions based on risk indexes. However, for the nuclear licensing, the CNEN request through their regulatory instruments and standard formats, that the risks, the failure mechanisms and detection be identified, which can allow the preventive and mitigate actions. This paper proposes the utilization of the FMEA (Failure Mode and Effects Analysis) technique in the licensing process. It was implemented a software through the Excel program, using the Visual Basic for Applications program which allows the automation and the standardization of FMEA studies as well

  15. CONFIANZA: EL RETO PARA LAS CIENCIAS SOCIALES

    Directory of Open Access Journals (Sweden)

    Juan José Plata C.

    2009-01-01

    Full Text Available El artículo presenta una reflexión sobre el papel de las ciencias sociales en el mundo moderno, resaltando como los orígenes, principios y fundamentos que la sustentan, nos permiten orientar posibles soluciones en el actual conflicto social. Para lo anterior acudimos a una metodología descriptiva entre metáforas, conocimiento y desarrollo

  16. Gasohol : un combustible limpio para Colombia

    OpenAIRE

    Ocampo González, Aquiles

    1998-01-01

    Se describe un estudio sobre las posibilidades reales que tiene Colombia de establecer un programa masivo para utilizar mezclas de etanol y gasolina como combustible automotor, teniendo en cuenta que la materia prima más probable deberá ser la caña de azúcar. Se discuten los efectos ambientales, socioeconómicos y técnicos de dicho programa.

  17. Diagnóstico molecular para Leishmaniasis

    Directory of Open Access Journals (Sweden)

    Ysabel Montoya

    1997-01-01

    Full Text Available El potencial diagnóstico de epitopes inmunodominantes seleccionados fue ensayado satisfactoriamente a fin de obtener una prueba serodiagnóstica alternativa para la Leishmaniasis Tegumentaria Americana. Dos proteínas recombinantes prometedoras de L. (v. peruviana referidas como T-26-U2/T26-U4 fueron reconocidas por sueros individuales de pacientes con Leishmaniasis Tegumentaria Americana usando Western Blot. La sensibilidad de la prueba fue de 86% con sueros permanentes con Leishmaniasis peruana.

  18. Observadores Distribuidos Garantistas para Sistemas en Red

    Directory of Open Access Journals (Sweden)

    Ramón A. García

    2017-07-01

    Full Text Available Resumen: En este artículo se propone un observador distribuido garantista para sistemas en red, considerando de forma explícita el problema de los retardos variables en las comunicaciones. Se asume que la información intercambiada entre agentes llega siempre a su destino, si bien las comunicaciones están sujetas a retardos variables, cuyo valor máximo se supone conocido. Cada observador trabaja con información parcial, y necesita comunicarse con observadores vecinos para llevar a cabo una estimación del estado completo del sistema. Para representar a los conjuntos garantistas, cuya función es acotar en tiempo real la región en la que se encuentra el estado del sistema, se ha optado por la utilización de zonotopos. Esto permite integrar de forma sencilla la información recibida por cada agente. Finalmente se presentan resultados de simulación para validar el algoritmo propuesto. Abstract: This paper proposes a guaranteed distributed observer for networked systems, taking into account the problem of the variable delays in communications. We assume that the information exchanged among the agents always arrives to its destination, although the communication are subject to variable delays, whose maximum value is known. Each observer works with partial information, and needs to communicate with neighbouring observers to carry out an estimation of the complete state of the system. The guaranteed sets, whose function is to delimit in real time the region in which the state of the system belong to, are represented by zonotopes. This kind of sets allows a simple integration of the information received by each agent. Finally some results obtained with the proposed algorithm are shown in simulations. Palabras clave: Estimación Distribuida, Observadores de Estado, Sistemas con Retardos, Sistemas en red, Zonotopos, Keywords: Distributed Estimation, State Observers, Delays Systems, Networked systems, Zonotopes

  19. Masculinidad-masculinidades. Camino para un cambio

    OpenAIRE

    Rodríguez del Pino, Juan Antonio

    2017-01-01

    Taller para trabajar en el aula el género (Masculinidad). Analizar como se construye la masculinidad así como influye en ese proceso el Patriarcado. Analizar el papel de los hombres en la sociedad. Determinar como viven los hombres su sexualidad y los conceptos de Micromachismos y posmachismos. Como hacerles frente y propuestas de nuevas formas de ser hombre, más igualitario

  20. ALGUNAS CARTAS DE CONTROL BIVARIADAS PARA ATRIBUTOS

    Directory of Open Access Journals (Sweden)

    CAROLINA OSPINA HINCAPIE

    2010-01-01

    Full Text Available Muchos procesos industriales son de naturaleza multivariada dado que la calidad de un producto depende de más de una variable. El control multivariado de procesos captura la relación en las variables asociadas al proceso, si se ignora esta correlación y se utilizan gráficos de control univariados para cada variable por separado se puede concluir erróneamente acerca del estado del proceso. En variables continuas correlacionadas se han realizado muchas investigaciones, sin embargo se encuentran pocos trabajos que traten sobre atributos correlacionados. En este trabajo se comparan tres cartas de control para variables aleatorias binomiales bivariadas, correlacionadas entre sí, las cuales miden atributos. Las cartas son: La carta de Hotelling basada en la aproximación de la distribución binomial multivariada a la distribución normal multivariada. La carta MNP la cual es una extensión de las cartas univariadas, y la carta que es una metodología no paramétrica basada en el índice de profundidad de Mahalanobis. La comparación se hace vía simulación utilizando como medida de comparación, la longitud promedio de racha (ARL. Dentro del trabajo se presenta un ejemplo aplicado de las metodologías para construir cartas de control para variables binomiales bivariadas en una empresa de telecomunicaciones. De los resultados se aprecia, en términos generales, que la carta MNP es la mejor tanto en control como fuera de control.

  1. Ecuaciones de diferencias mejoradas para ecuaciones diferenciales

    OpenAIRE

    Lick, Wilbert

    1985-01-01

    Se presenta en este artículo una resena sobre el uso del método integral para derivar ecuaciones de diferencias a partir de ecuaciones diferenciales. El método se aplica a varios tipos de ecuaciones diferenciales ordinarias correspondientes a problemas de valores de contorno y a problemas de valores iniciales, ilustrándose la utilidad del método con varios ejemplos sencillos. Peer Reviewed

  2. Factores claves para iniciar una empresa

    Directory of Open Access Journals (Sweden)

    Irenarco Rueda Reyna

    2015-04-01

    Full Text Available RESUMEN El artículo presenta en forma esquemática los aspectos relevantes para la conformación de una empresa,  desde la planeación acertada, el mercado, los medios de producción,  personal y financiamiento. Resalta asimismo la importancia de las clasificaciones y características que debe tener el indicador  de negocios.

  3. Receptores para el virus de la rabia

    Directory of Open Access Journals (Sweden)

    Jaime E. Castellanos

    2001-12-01

    Full Text Available El virus de la rabia causa una infección en el sistema nervioso que puede provocar la muerte. La patogenia y el neurotropismo de este virus han sido estudiados extensamente con el objeto de explicar el porque la letalidad de la enfermedad y proponer nuevas alternativas terapéuticas. El proceso de adsorción del virus a la célula bianco se considera un evento que define el neurotropismo del virus. Se piensa que debe existir una molécula en la superficie de las neuronas que une con alta afinidad al virus y da comienzo al proceso infeccioso. Durante los últimos años se han propuesto varias proteínas, carbohidratos y lipidos complejos, como receptores para el virus de rabia y se han hecho nuevas proposiciones de terapia antirreceptor. Además de los gangliósidos y fosfolípidos para los que se ha hallado evidencia sobre su participación en la adsorción del virus de la rabia, hay datos experimentales sobre la participación del receptor nicotinico de acetilcolina. la molécula de adhesión celular neural y el receptor de baja afinidad para neurotrofinas en la infección neurona1 En este articulo se hace una revisión de los datos que sustentan a cada una de las moléculas propuestas, se discuten sus implicaciones para la explicación del neurotropismo del virus de rabia y la exploración de nuevas terapias antivirales.

  4. Recomendaciones para la vigilancia de Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Roberto Barrera

    2016-09-01

    Full Text Available La enfermedades causadas por arbovirus transmitidos por Aedes aegypti, como el dengue, el chikungunya y el zika, continúan aumentando en incidencia anual y expansión geográfica. Una limitación clave para el control de A. aegypti ha sido la ausencia de herramientas eficaces para vigilar su población y poder determinar las medidas de control que realmente funcionan. La vigilancia de A. aegypti se ha basado principalmente en la obtención de los índices aédicos, los cuales guardan poca relación con el número de hembras del mosquito, que son las responsables de la transmisión de los virus. El reciente desarrollo de técnicas de muestreo de adultos de este vector promete facilitar las labores de vigilancia y control. En esta revisión se presentan las diversas técnicas de vigilancia del mosquito, así como una discusión sobre su utilidad, con recomendaciones para lograr una vigilancia entomológica más efectiva.

  5. EXPERIENCIA INTEGRADORA PARA EDUCACIÓN AMBIENTAL

    Directory of Open Access Journals (Sweden)

    Jorge F. Coronel

    2015-01-01

    Full Text Available En este trabajo se relacionó la práctica experimental de laboratorio co n el análisis de problemas ambientales. El objetivo de este trabajo es analizar una propuesta que vinculó el trabajo experimental con la situación del ambiente local para promover el cuidado de la naturaleza y su uso con sostenibilidad . Esta estrategia brindó un enfoque integrador aportando a los alumnos de profesorado una alternativa de aprendizaje con exper iencias sencillas para el estudio cualitativo de l ambiente local y motivar a l análisis de problemas asociad o s. Las experiencias permitieron caracterizar las muestras de suelo, agua y aire del lugar de residencia de los alumnos. La información experimental obtenida potenció la discusión de la situación ambiental actual. E l enfoque de enseñanza basado en problemas socio - científicos posibilit ó la visión interdisciplinar del tema , redimensionando valores y acciones para el cuidado ambiental y el desarrollo sustentable.

  6. Experimentos en Antioquia con Fertilizantes para Papa.

    Directory of Open Access Journals (Sweden)

    Yepes Y. Emilio

    1949-03-01

    Full Text Available Con el fin de determinar la adecuada aplicación de cal. y la economía de la adición de Nitrógeno, Fósforo y Potasio, se realizaron varios experimentos de fertilizantes para papa en dos regiones productoras de Antioquia. Los experimentos se realizaron por el sistema de "Parcelas divididas y del análisis estadístico de los resultados pueden sacarse las siguientes conclusiones: 1. Es notable la deficiencia de Fósforo en ambos suelos, y hubo respuesta significativa a una aplicación de 120 kilos por hectárea. 2. Los suelos responden a una aplicación moderada de Nitrógeno y Potasio, pero puede lograrse una economía importante en las cantidades de estos elementos. 3. Parece que la aplicación de dos toneladas de cal por cuadra es suficiente, y no hay razón para aconsejar cantidades mayores. 4. Los resultados obtenidos demuestran que sí es posible la experimentación con fertilizante para papa, y sería de desear que se ampliara la experimentación en las demás regiones productoras.

  7. Cirurgia para controle de danos: estado atual

    Directory of Open Access Journals (Sweden)

    Rodrigo Camargo Leão Edelmuth

    Full Text Available A cirurgia de controle de danos é um conceito amplamente aceito atualmente entre os especialistas em trauma abdominal quando se trata de doentes gravemente traumatizados. Nestes pacientes a morte decorre, na maioria das vezes, da instalação da tríade letal (hipotermia, coagulopatia e acidose e não da incapacidade de reparar as graves lesões presentes. Nesta revisão, os autores abordam a tríade letal, em suas três fases, e enfatizam as medidas adotadas para preveni-las. Além de discutirem a indicação e o emprego da cirurgia para o controle de danos em seus vários estágios. A restauração dos padrões fisiológicos do doente na UTI, para que o mesmo possa ser submetido à operação definitiva e ao fechamento da cavidade abdominal, outro desafio no paciente traumatizado grave, também é discutida.

  8. UM MODELO INFORMACIONAL PARA EMPRESAS MULTIPLANTA

    Directory of Open Access Journals (Sweden)

    Rogério Matos Dias

    2006-09-01

    Full Text Available Este estudo objetiva conceber, testar e demonstrar a aplicabilidade de um modelo informacional que possibilite a gestão integrada das operações da cadeia de suprimentos para firmas geograficamente dispersas – também denominadas empresas multiplanta. Para tanto, foram aplicados os métodos de pesquisa de caso e pesquisa-ação em uma empresa representativa do setor mínero-metalúrgico em âmbito mundial, a Rio Doce Manganês S.A., subsidiária da Cia. Vale do Rio Doce. A pesquisa pretende demonstrar que o modelo de sistema informacional proposto, por meio da automatização dos processos transacionais e gerenciais, é capaz de prover recursos de planejamento e controle nos níveis operacional, tático e estratégico, devido a sua capacidade de incrementar velocidade e qualidade nos processos de análise e decisão. Adicionalmente, pretende conduzir, após análise dos resultados e avaliação das contribuições a empresa estudada, a um modelo informacional adequado para gerir as operações de outras empresas de mineração e metalurgia com características semelhantes.

  9. HACER PARA PENSAR: IDEAS, ESPACIOS Y HERRAMIENTAS

    Directory of Open Access Journals (Sweden)

    Claudia Urrea Giraldo

    2012-01-01

    Full Text Available Con el presente ensayo se busca compartir la experiencia de aprendizaje diseñada y desarrollada por un grupo interdisciplinario de profesores y profesoras de la Universidad de Costa Rica. La actividad contó con la participación de docentes de distintas disciplinas académicas. La propuesta se concretó en un taller que utilizó el lenguaje de programación Scratch y las tarjetas Pico, como oportunidad para modelar un ambiente de aprendizaje construccionista. Ideas poderosas, espacios y herramientas se pusieron a disposición de los y las participantes para la construcción de historias digitales, modelos y simulaciones. El objetivo final fue que los y las profesoras pudieran vivenciar, a través de una experiencia práctica, el ambiente de aprendizaje construccionista, las ideas y las herramientas, para que más adelante las pudieran extrapolar en sus propias disciplinas y cursos.

  10. VIABILIZADORES PARA A SUPPLY CHAIN MANAGEMENT

    Directory of Open Access Journals (Sweden)

    Annibal José Scavarda

    2004-12-01

    Full Text Available Acadêmicos e industriais refletiram recentemente sobre os paradigmas do desenvolvimento dos sistemas produtivos, revendo as lógicas de produção industrial, comercialização e relacionamento entre empresas. Isso acarretou fortes mudanças na cadeia de suprimentos de diversas indústrias. A gestão da cadeia de suprimentos (Supply Chain Management – SCM tem criado oportunidades e desafios para a competição no mundo dos negócios. O sucesso da implementação dessa nova forma de gestão somente é alcançado através do uso correto de seus diferentes viabilizadores. O objetivo deste artigo é apresentar, descrever e analisar os viabilizadores-chave para a SCM e, com isso, compreender a relevância do seu uso combinado. Os viabilizadores da SCM analisados são os seguintes: nível de relacionamento externo com outros membros pertencentes à mesma cadeia, integração dos processos de negócios entre esses membros, tecnologia de informação e gestão de recursos humanos. Para que estimulem e consolidem iniciativas de SCM, é necessário abordá-los em conjunto e não de forma isolada.

  11. Erosividade da chuva para o bioma Pantanal

    Directory of Open Access Journals (Sweden)

    Daniel Okamoto Machado

    2014-06-01

    Full Text Available A escassez de dados pluviográficos na região do Pantanal fez com que muitos autores utilizassem equações de regressão obtidas em outras regiões do Brasil para calcular o Fator R da Equação Universal de Perda de Solo (USLE. O presente estudo define equações para a previsão da erosividade em região do bioma Pantanal, correlacionando a erosividade das chuvas calculada pelo índice EI30 e o coeficiente de chuva (Rc. A equação desenvolvida, do tipo potencial, apresenta consistência e correlação significativa com os dados observados, obtendo valor de coeficiente de determinação de 97%. Portanto, a equação de erosividade proposta pode ser utilizada para estimativa do fator R da USLE a partir dos dados mensais e anuais de precipitação da região e de outras regiões com características climáticas semelhantes.

  12. A leitura: um passaporte para a vida

    Directory of Open Access Journals (Sweden)

    Armindo Teixeira Mesquita

    2011-06-01

    Full Text Available Nas sociedades actuais, a capacidade para usar material escrito é indispensável ao acesso a todo tipo de informação, tornando o uso da leitura cada vez mais necessário à participação real do cidadão em actividades produtivas e colectivas, porque ajuda a formar seres pensantes. O contacto com os livros deve ser iniciado o mais cedo possível, não só pelo manuseio, como também pela história contada ou pelos jogos rítmicos. Com efeito, na idade da infância, toda a energia do indivíduo é dirigida para a construção da sua identidade. Logo, as primeiras leituras entram no período da formação e da fundação, isto é, consignamos à leitura uma grande força de desenvolvimento pessoal. Os livros, para além de auxiliares na aprendizagem do mundo, formam o leitor no gosto. Formar o gosto e possibilitar escolhas são realidades fundamentais na vida adulta.

  13. Cuestionarios Interactivos para Autoevaluación

    Directory of Open Access Journals (Sweden)

    Sánchez García, Juan Francisco

    2007-01-01

    Full Text Available La autoevaluación es un instrumento valioso para que el propio alumno pueda medir el grado de conocimientos adquiridos de la materia en cuestión, al tiempo sirve para adiestrarlo en el tipo de prueba que se utilizará posteriormente en el examen. Por otro lado, dado que en la adaptación al Espacio Europeo de Educación Superior (E3S tiene particular importancia la labor realizada por el propio alumno, los pruebas de autoevalución adquieren, si cabe, una mayor relevancia. Por todo ello, hemos elaborado unos test interactivos con hoja de calculo, para cubrir el doble propósito de evaluar los conocimientos alcanzados por nuestros alumnos, relativos tanto a la materia, como al manejo en sí de la propia herramienta informática de la hoja de cálculo. Se muestran ejemplos concretos relacionados con las matemáticas y la hoja de cálculo Excel.

  14. Meios e fins do desenvolvimento para Celso Furtado

    Directory of Open Access Journals (Sweden)

    Fabio Antonio de Campos

    2014-10-01

    Full Text Available O objetivo desse artigo é expor o conceito de desenvolvimento para Celso Furtado. Para tanto, nos interessa apresentar o desenvolvimento nacional como um fim em sua abordagem sobre a formação social brasileira Para atingir tal estágio, os meios para o autor seriam assegurados por um típico desenvolvimento capitalista. Dentro dessa problemática, mostraremos também o alcance e os limites dessa concepção para o caráter dependente e subdesenvolvido do capitalismo brasileiro.

  15. Competencia para desarrollar la alfabetización digital

    OpenAIRE

    González Rodríguez, José Santiago; Navarrete Aguirre, Mariana; Molina Zacate, Ma. Gabriela

    2011-01-01

    Introducción, Objetivos Generales, Temario: (1) ¿Qué significa la competencia para desarrollar la alfabetización digital? (2) ¿Por qué es relevante que adquiera la competencia para desarrollar la alfabetización digital en mi formación? (3) ¿Cómo aprendo la competencia para desarrollar la alfabetización digital? (4) ¿Cómo aplico la competencia para desarrollar la alfabetización digital? (5) ¿Cómo puedo autoevaluar mi competencia para desarrollar la alfabetización digital (...

  16. Docencia para el logro y educación para emprender

    Directory of Open Access Journals (Sweden)

    Luis Gerardo Rodríguez Gómez

    1994-05-01

    Full Text Available RESUMEN En el primer artículo, el autor plasmó los elementos relevantes para una propuesta de educación para emprender. En este describe el desarrollo docente como expresión de una intensión, saber y un quehacer, encaminados a la formación del hombre emprendedor. El artículo se divide en tres partes. En la primera, se reseña los factores que orientan la intensión docente para emprender, a partir de un discurso y formas metodológicas establecidas con esa intención. En segundo lugar, se asume el espacio y tiempo la clase como unidad de análisis, para lograr objetivos de tipo institucional, programático y temático y en la parte final, se examina la evaluación docente y se hacen consideraciones generales para una propuesta de evaluación,  que surge al investigar la actuación del maestro.

  17. Labbtex: Toolbox para generación de informes en LATEX para Matlab

    Directory of Open Access Journals (Sweden)

    José Luis Almazán Gárate

    2012-10-01

    Full Text Available En este artículo se presenta el software desarrollado por el Equipo H3lite dentro del Departamento de Ingeneniería Civil. Transportes de la Escuela de Ingenieros de Caminos, Canales y Puertos de la Universidad Politécnica de Madrid para la generación de informes enLATEX mediante el software Matlab® y la integración en sus rutinas, Labbtex.La librería Labbtex proporciona un marco flexible para mezclar texto y código Matlab® para la generación automática de documentos. Un rchivo fuente simple contiene el texto de documentación y el código Matlab, al correr la aplicación se genera un documento final LATEX que contiene el texto, gráficos y tablas indicados con el formato de un documento LATEX. El código Matlab genera un documento LATEX usando la sintaxis. Así, LATEX (para composición de texto de alta calidad y Matlab® (para cálculo matemático pueden usarse simultáneamente. Esto permite la generación de informes en tiempo real con un uso de recursos mínimo.

  18. ELEMENTOS PARA LA CONSTRUCION DE UN PERFIL PARA EL GERENTE SOCIAL EN UN ENTORNO GLOBALIZADO

    Directory of Open Access Journals (Sweden)

    Antonio Bastidas Unigarro

    2009-07-01

    Full Text Available El perfil del gerente social adecuado para enfrentar los retos del mundo globalizado se ha estructurado a partir de cuatro requerimientos fundamentales: los conocimientos, la experiencia, las habilidades y las actitudes, los cuales se analizan como competencias indispensables para administrar la problemática compleja, llena de incertidumbres y desafíos del nuevo milenio. La propuesta para la construcción de un perfil de este gerente parte de considerar tres tipos de competencias: las funcionales, las comportamentales y los requisitos de estudio y experiencia. Su construcción parte del análisis de la Gerencia Social en el estado neoliberal, escenario, que reclama la formación de gerentes sociales comprometidos en la construcción de una sociedad mas justa, incluyente, participativa, democrática y solidaria.

  19. Procedimiento para el cierre de canteras de materiales para construcción en Cuba

    Directory of Open Access Journals (Sweden)

    Julio Montero-Matos

    2016-03-01

    Full Text Available Con el propósito de facilitar a los concesionarios de canteras de materiales para la construcción una herramienta metodológica para efectuar el cierre de estas y garantizar una minería sostenible se propuso un procedimiento en seis etapas a partir del diagnóstico realizado en 22 canteras, ubicadas en tres regiones mineras cubanas. El procedimiento busca disminuir los impactos ambientales provocados por la explotación de las canteras y ofrecer a la industria un estándar para lograr uniformidad en la planificación y ejecución del cierre con un costo mínimo.

  20. La estrategia educativa 2020 o las limitaciones del Banco Mundial para promover el "aprendizaje para todos"

    Directory of Open Access Journals (Sweden)

    Antoni Verger

    2011-12-01

    Full Text Available LA NUEVA Estrategia Educativa 2020 del Banco Mundial establece las prioridades de reforma educativa en países en vías de desarrollo para la década siguiente. El título explícito de la estrategia, Aprendizaje para Todos, es un claro reconocimiento de que, más allá de políticas centradas en el acceso, se debe hacer algo más para asegurar que la educación derive en experiencias positivas de aprendizaje. Sin embargo, como este artículo sostiene, las opciones de políticas explícitas y latentes en la Estrategia 2020 no son las más adecuadas para lograr el Aprendizaje para Todos. El artículo desarrolla tres tipos de argumentos al respecto. El primero se refiere al fuerte apego del Banco a un conocimiento disciplinario y un enfoque metodológico que es insuficiente para entender lo que aprenden los niños en la escuela y por qué. El segundo argumento se refiere al sesgo pro-mercado de la Estrategia por lo que respecta a la reforma del sector público y a nuevas formas de oferta educativa. En tercer lugar, el artículo señala las principales ausencias de la Estrategia, con especial atención a las omisiones relacionadas con la compleja relación entre educación y pobreza.

  1. Flora da Paraíba, Brasil: Loganiaceae Flora of Paraíba, Brazil: Loganiaceae

    Directory of Open Access Journals (Sweden)

    Kiriaki Nurit

    2005-06-01

    Full Text Available Neste trabalho apresenta-se o tratamento taxonômico da família Loganiaceae, como parte do projeto "Flora da Paraíba", que vem sendo realizado com o objetivo de identificar e catalogar as espécies da flora local. Realizouse coletas e observações de campo para as identificações, descrições e ilustrações botânicas que foram efetuadas após estudos morfológicos, com o auxílio da bibliografia especializada, complementados pela análise de fotos de tipos, espécimes dos herbários EAN, JPB e IPA, e comparação com material identificado por especialistas. Registrou-se para a Paraíba quatro espécies: Spigelia anthelmia L., com ampla distribuição, e três espécies de Strychnos, somente coletadas em remanescentes de Mata Atlântica, S. atlantica Krukoff & Barneby, S. parvifolia A. DC. e S. trinervis (Vell. Mart.This work constitutes a taxonomic treatment of the Loganiaceae family as part of the project "Flora da Paraíba", which have been carried out with the objective to identify and catalogue the species of the local flora. The botanical identifications and illustrations were made by morphological studies supported by bibliography, analysis of the types, specimens from herbaria EAN, JPB and IPA, and comparison with samples previously identified by specialists, complemented by field observations. Four species of Loganiaceae belonging two genera were found in State of Paraíba: Spigelia anthelmia L. that has wide distribution and three species of Strychnos, found on remains of Atlantic forest, which are S. atlantica Krukoff & Barneby, S. parvifolia A. DC. and S. trinervis (Vell. Mart.

  2. Propuesta para un plan de marketing para el Hotel Haro ubicado en la ciudad de Cuenca

    OpenAIRE

    López Zúniga, Susana Cristina; Yanza Barrera, Mariana de Jesús

    2008-01-01

    El plan de marketing es una herramienta de gestión que sirve de base para los otros planes de la empresa como puede ser el plan de producción o el financiero, determina responsabilidades, permite revisiones y controles periódicos para resolver los problemas con anticipación, evitar pérdidas económicas y ayuda a la empresa a estar lista frente a los riegos y oportunidades que se presenten en el mercado. En el espacio donde el mercado se convierte cada vez más competitivo hay menos posibilid...

  3. Sistema de autenticidad para aplicaciones de análisis de eventos para seguridad.

    OpenAIRE

    ESCAMILLA PARDO, TONI

    2017-01-01

    [ES] En este proyecto se afronta la creación de un sistema distribuido capaz de garantizar, en aplicaciones empleadas para el análisis de eventos de seguridad, la autenticidad de los datos transmitidos entre el host cliente y servidor con el fin de asegurar la integridad de los mismos en la transmisión entre ambas partes, así como evitar la posible alteración en el destino. Para ello, se utilizará la tecnología blockchain a modo de base de datos en la que se almacenen los hashe...

  4. Plan de negocio para una empresa que alquila bombas sumergibles para el sector minero

    OpenAIRE

    Pérez León Corzo, Stepahnie Pamela

    2016-01-01

    El presente trabajo de investigación evalúa la viabilidad operativa y financiera para operar una pequeña empresa dedicada al alquiler de bombas sumergibles para la actividad de desagüe de medianas y pequeñas empresas del sector minero. Estructuralmente, la empresa estará constituida por la alta dirección conformada por tres socios quienes aportarán el 30% de la inversión inicial, el 70% restante se obtendrá mediante un financiamiento a mediano plazo con un banco local. La línea media estará c...

  5. La Escucha Efectiva. Recomendaciones para lograrla.

    Directory of Open Access Journals (Sweden)

    Mariano Álvarez Farfán

    2009-10-01

    Full Text Available La comunicación es y seguirá siendo una condición de la existencia humana. Aún avanzando por las sendas del siglo XXI es imposible vivir sin dedicarle atención priorizada a este proceso. Dentro de él un lugar primordial lo ocupa la habilidad de escuchar. Saber escuchar es una de las habilidades más importantes que debe tener un profesional e incluso cualquier persona común de la sociedad. En los últimos años los especialistas han venido dedicando una atención especial a esta habilidad, dándole un tratamiento relativamente independiente dentro de los estudios sobre el proceso de comunicación. En investigaciones realizadas sobre las habilidades que debe tener todo buen comunicador se ha determinado que la más necesaria y difícil de lograr es la de saber escuchar. Realmente pasamos más tiempo escuchando que hablando, pero no son muchos los que se pueden calificar como buenos oyentes. Los estudiosos del tema a nivel mundial coinciden también que desarrollar esta habilidad requiere, de una gran voluntad y disposición hacia el cambio de enfoques, conductas y formas de ver las cosas, porque solo hay una manera de lograrlo y es luchando desde “dentro” del individuo. En el trabajo se ofrecen diferentes opiniones y enfoques que pueden contribuir a desarrollar esta habilidad tan importante, para el trabajo profesional y para las relaciones interpersonales. Se enfatiza en los beneficios que reporta una buena escucha, qué entender por una buena escucha o escucha efectiva y las recomendaciones para lograr esa escucha efectiva.

  6. Software educativo para enfermería

    Directory of Open Access Journals (Sweden)

    Mac Gaul de Jorge, Marcia Ivonne

    2009-01-01

    Full Text Available El presente trabajo relata la experiencia de investigación del proyecto investigación del proyecto Nº 1531 del CIUNSa, "Software Educativo para Enfermería del Adulto". El equipo integra a enfermeras, quienes en el año 2003 elaboraron un material que responde a la realidad epidemiológica de nuestro país, marcadamente diferente a textos clásicos provenientes de otras regiones del mundo. Convencidos que las universidades deben dar respuestas a los problemas regionales, se están desarrollando materiales educativos que, aprovechan las ventajas que la Informática brinda (altamente interactivos y que pueden actualizarse permanentemente. Esta investigación está finalizando su etapa diagnóstica, la cual posee dos objetivos específicos para el desarrollo del producto software: uno tendiente a indagar las competencias de los alumnos de Ciencias de la Salud con relación al uso de materiales educativos informatizados; el otro, modelar el sistema informático del cual serán usuarios los alumnos y docentes, para lo cual se están realizando actividades de Ingeniería de Requerimientos que permitan establecer el contexto en el que se utilizará el software desarrollado. Creemos que el estudio diagnóstico culminado sitúa a nuestros alumnos en la misma sintonía de los desarrolladores. Sus expectativas por un recurso efectivamente didáctico coinciden con nuestras directrices de diseño.

  7. Manual de protocolo para empresas hoteleras

    OpenAIRE

    Román-del-Monte, Annabelle Valentina

    2011-01-01

    Este proyecto propone la implementación de un manual de protocolo para empresas hoteleras, especialmente aquellas que reciben clientes pertenecientes al turismo de negocios. Frente a la mayor competencia existente,y en el actual contexto de crisis, las empresas buscan hoy día diferenciarse de las demás a través de la calidad. Una herramienta útil es el “protocolo aplicado a la empresa”. El protocolo anteriormente se entendía como una regla estricta, estrechamente unida al ámbito diplomá...

  8. Obras nacionalistas brasileiras para violoncelo e piano

    OpenAIRE

    Borges, Gabriel Saliba e

    2012-01-01

    Este trabalho tem por finalidade complementar o projeto de performance musical que se baseia em três obras para violoncelo e piano de distintos compositores brasileiros, compostas no período em que estes compartilhavam os mesmos ideais nacionalistas, porém expressados de formas diferentes. Francisco Mignone, José Guerra Vicente e Camargo Guarnieri, contemporâneos e que figuram entre os grandes compositores brasileiros do séc. XX, fazem parte do hall de compositores nacionais, a que se soma...

  9. Robot Saltador y Procedimiento para su Control

    OpenAIRE

    Akinfiev, Teodor; Armada, Manuel; Fernández, Roemi; Montes, Héctor

    2005-01-01

    Robot saltador para el movimiento en terrenos con obstáculos, que contiene al menos un resorte (4) con uno de sus extremos unido al cuerpo (1) del robot, y una cadena cinemática entre el motor (5) y el resorte (4) que comprende un cilindro (7) conectado con el eje del motor (5) y una cuerda (8), con uno de sus extremos conectado al cilindro (7) y con el segundo extremo conectado al pie (3). El procedimiento de control se caracteriza porque en el momento en el que el pie (3) pierde el contacto...

  10. Software para Controle de Temperatura em Estufas

    OpenAIRE

    Silva, Antonio Carlos Alves; Universidade Federal de Lavras; Kanazawa, Edna Mie; Universidade Federal de Lavras; de Carvalho, Karina Dutra; Universidade Federal de Lavras; Kinoshita, Vanessa Godoy; Universidade Federal de Lavras; Uchoa, Joaquim Quinteiro; Universidade Federal de Lavras; Lacerda, Wilian Soares; Universidade Federal de Lavras; Schneider, Bruno de Oliveira; Universidade Federal de Lavras

    2004-01-01

    Neste trabalho é apresentado o projeto desenvolvido para controle de temperatura em estufas, denominado CTE, utilizando uma Interface de Aquisição e Controle de Dados. Todo o controle é feito via software, onde pode-se optar por dois tipos de controle: o controle automático, onde é possível definir-se a temperatura mínima e máxima; ou o controle manual, onde o usuário poderá optar por acionar periféricos de aquecimento, resfriamento e desligamento da estufa. Foi desenvolvida também uma interf...

  11. Notas para los Colaboradores del Index Botanicorum

    Directory of Open Access Journals (Sweden)

    Verdoorn Frans

    1946-12-01

    Full Text Available EL INDEX BOTANICORUM: -Al discutir la necesidad de un diccionario biográfico de los botánicos del mundo y de todos los tiempos. JAMES BRITTEN (J. Bot. 39: 394. 1901 afirma: “Este formaría un compendio manual y útil no solamente de biografías botánicas sino de investigación botánica y sería de valor incalculable para el historiador y el estudiante” En el siguiente artículo se habla de las pautas que deben seguir los colaboradores del Index Botanicarum al escribir en dicho diccionario.

  12. Arquitectura empresarial para corresponsales no bancarios

    OpenAIRE

    Palacino Díaz, Alejandro; Rodríguez de Silvestre, Carlos Eduardo

    2011-01-01

    La arquitectura empresarial permite alinear el desarrollo tecnológico de una organización con su visión y estrategia. El presente trabajo de grado propone una solución tecnológica al procesamiento transaccional de CNB para entidades financieras en Colombia, mitigando riesgos de operación y reduciendo los limites impuestos por el manejo del efectivo en poblaciones remotas, enmarcada dentro de TOGAF como marco de referencia de arquitectura empresarial. El desarrollo de la arquitectura parte de ...

  13. Practicas para laboratorio de principios de riego

    OpenAIRE

    Arango Tobón, Julio César

    1998-01-01

    Familiarizar al estudiante con los diferentes tipos de vertederos como elementos aforadores, en lo que respecta a su correcta instalación, toma de datos y utilización de los mismos en las labores de riego. Obtener un conocimiento detallado del aforador Parshall, establecer los requisitos necesarios para una correcta instalación y observar el funcionamiento de esta estructura aforadora. El objetivo de esta práctica es determinar el coeficiente de pérdida de carga hidráulica en un tubo q...

  14. Plan para control de Malaria en Colombia

    Directory of Open Access Journals (Sweden)

    Hernando Rey

    1943-02-01

    Full Text Available Con motivo de la colaboración de la Oficina de Relaciones Interamericanas en la solución de algunos problemas de Higiene pública en Colombia, el Secretario del Ministerio de Trabajo, Higiene y Previsión Social, doctor Alfonso Orozco, me pidió la elaboración de un breve plan para control de Paludismo en Colombia. El Plan fué presentado al Ministerio por una parte y por otra enviado al doctor Mark F. Boyd de la International Health Division de la Fundación Rockefeller.

  15. Los ritmos como terapia para la impulsividad

    Directory of Open Access Journals (Sweden)

    Mónica Triviño

    2012-10-01

    Full Text Available Investigaciones recientes muestran que el uso de patrones rítmicos facilita la respuesta óptima en el tiempo, por lo que el entrenamiento mediante ritmos podría proponerse como terapia novedosa ante problemas como la impulsividad. Esto podría beneficiar a pacientes con daño prefrontal o personas con trastorno por déficit de atención e hiperactividad (TDAH, que suelen mostrar conductas impulsivas, así como dificultad para estimar el paso del tiempo.

  16. Una reforma constitucional para la periferia europea

    OpenAIRE

    Gerardo Pissarello

    2011-01-01

    La intempestiva reforma del artículo 135 de la Constitución española puede leerse como una expresión más de la erosión en Europa de los elementos garantistas del constitucionalismo de posguerra. Tanto por su contenido como por el procedimiento empleado para acometerla, su aprobación aparece reñida con principios constitucionales básicos, como el democrático, el del Estado social o el de la autonomía territorial. Asimismo, supone un golpe a la legitimidad global de la Constitución cuya reversi...

  17. Para tener entre manos una revista

    OpenAIRE

    Gabriel Giannone

    2017-01-01

    Consideramos importante rescatar el trabajo colectivo y acumulado que precede y sucede a la labor de intermediación académica que realiza una revista. Para ello recordamos una clásica frase prologal: el texto que usted tiene en sus manos. Con cierta ironía, porque quizás muy pocos de los lectores puedan tener entre manos y oler el papel impreso de Chasqui. Desde sus pantallas, sus tablets o sus teléfonos la intención es que se comprenda este número como un solo cuerpo. Y al mismo tiempo, como...

  18. 11 Verduras para Diversificar la Dieta Peruana

    OpenAIRE

    Ugas, Roberto; Loayza, Sara; Chang, Agusto

    2013-01-01

    Los peruanos debemos comer más verduras. Estos alimentos son fuentes esenciales de vitaminas, minerales, antioxidantes y fibra alimentaria y la ciencia muestra día a día su contribución a la prevención de enfermedades. Para tener un estilo de vida saludable es necesario comer diariamente cinco porciones de frutas y verduras y hacer ejercicio físico regularmente. Aquí presentamos una lista corta de once hortalizas de hoja, algunas son yuyos de uso tradicional en el campo peruano, otras son ver...

  19. Plan de Marketing para Muebles Moncayo

    OpenAIRE

    Foyes Jiménez, Fermín

    2017-01-01

    Treball Final de Màster Interuniversitari en Màrqueting i Investigació de Mercats. Codi: SRB100. Curs: 2016/2017 El proyecto que se describe a continuación consiste en un Plan de Marketing para Muebles Moncayo, empresa de Barcelona dedicada a la comercialización al por menor de muebles de hogar. En la actualidad esta tiene una política de negocio clásica, ya que no tiene definidas las estrategias operativa y de negocio. Dada esta situación, se ha llevado a cabo un análisis de la situación,...

  20. Redes sociales para educomunicadores : recursos y experiencias

    OpenAIRE

    Universitat Autònoma de Barcelona. Máster en Comunicación y Educación (online)

    2013-01-01

    Las redes sociales han sido universalmente acogidas entre los usuarios de internet como una manera comprometerse en eventos, grupos sociales y temas de interés. Estos usuarios han encontrado en las redes un espacio para compartir información, socializar y, en muchos casos, construir verdaderas redes de cooperación y colaboración, un uso que puede ampliarse aún más en la medida en que madure la alfabetización mediática de sus participantes. Este informe muestra las principales redes sociales, ...

  1. Apontamentos para as aulas de Hidrologia

    OpenAIRE

    Rodrigues, Carlos Miranda; Guimarães, Rita Cabral; Moreira, Madalena

    2011-01-01

    Esta publicação constitui um manual de apoio aos alunos para a disciplina de Hidrologia, Hidrologia Agrícola e Interpretação da Paisagem. Nela são abordados os temas gerais da Hidrologia: Ciclo hidrológico; Bacia Hidrográfica; Precipitação; Intercepção; Evaporação e Evapotranspiração; Água no Solo, Escoamento Superficial; Balanço Hidrológico; Estudo das Cheias.

  2. Para um perfil do idoso-andarilho

    Directory of Open Access Journals (Sweden)

    Claudia Lysia de Oliveira Araújo

    2012-01-01

    Full Text Available O termo envelhecimento é frequentemente empregado para descrever as mudanças morfofuncionais que ocorrem ao longo da vida humana, após a maturação sexual e que, progressivamente, comprometem a capacidade de resposta dos indivíduos ao estresse ambiental e à manutenção da homeostasia. Na condição de pessoas em envelhecimento avançado e de vida fragilizada, são encontrados muitos idosos-andarilhos por estradas e ruas das cidades brasileiras. Definimos aqui andarilho como a pessoa que vive fora do lar, em um cotidiano muito simples, miserável até, afastado de relações familiares e sociais mais próximas, distanciados do sentido de uma vida dita normal. A falta deste sentido de vida, a que se alia o preconceito da sociedade, têm sido fatores que levam à estigmatização desses idosos abandonados, fazendo-os a acreditar que a rua é o único lugar que lhes resta para viver. O objetivo deste estudo foi conhecer os motivos que conduzem um idoso a se tornar andarilho, tendo sido realizado nos albergues das cidades do Vale do Paraíba, no Estado de São Paulo. O universo desta experiência foram alguns idosos sem moradia, independentemente de gênero. Identificamos, neste estudo, os idosos encontrados não por seus nomes reais, mas por meio da denominação dada a pedras preciosas. Eles relataram ter profissão, embora vivam sós, perambulando pelas ruas das citadas regiões urbanas. Quanto aos problemas de saúde, os idosos aqui entrevistados referiram alguma patologia, ainda que nenhum deles fizesse tratamento ou visitasse médico regularmente, por não disporem de documentos. Os relatos desses idosos-andarilhos apontam para uma condição de sobrevivência fragilizada, comprometida por se tornarem muito vulneráveis, susceptíveis a agressões externas, o que agudiza cada vez mais sua exclusão familiar e social. Por fim, verifica-se que eles ainda sonham em voltar ao lar e recomeçar a vida ao lado da própria família.

  3. Cómics para la Disfemia

    OpenAIRE

    Pomares Puig, María Pilar

    2015-01-01

    Desde la Facultad de Educación se vienen desarrollando diversas estrategias para fomentar el uso del cómic en distintos niveles escolares y profundizar en el conocimiento del mismo y ampliar la labor de divulgación que realiza la asociación de Unicómic http://unicomic.blogspot.com, centrándonos en los aspectos didácticos. La disfemia es un trastorno de la fluidez verbal y del ritmo del habla caracterizado por disfluencias consistentes en repeticiones y prolongaciones de sonidos y dificultad p...

  4. Herramienta para la Deteccion de Retinoblastoma

    OpenAIRE

    Vargas-Cuentas , Natalia Indira; Roman-Gonzalez , Avid

    2015-01-01

    International audience; El retinoblastoma, es un tumor que se presenta en la retina de las personas, especialmente en los niños. Una detección temprana del mismo, podría ser muy útil y salvar la vida del niño. Es en ese sentido, que el presente trabajo propone una herramienta sencilla para la detección de retinoblastoma analizando fotografías tomadas con flash en las cuales, en el ojo del niño se puede detectar la presencia de leucoria. Esta detección se realiza utilizando las funciones de de...

  5. Sistemas de custos para pequenas empresas industriais

    OpenAIRE

    Moraes, João Vicente de

    2002-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção. Este trabalho define um sistema de custos para pequenas empresas industriais, o qual permite identificar o custo, resultado e margem de contribuição por produto e ponto de equilíbrio , considerando o período de apuração do resultado. O sistema proposto é aplicado em um caso prático, em uma empresa estabelecida na cidade de Cascavel-PR., que produz rodas ...

  6. ESTRATEGIA INTEGRAL PARA PyMES INNOVADORAS

    Directory of Open Access Journals (Sweden)

    Jairo Sanchez Quintero

    2003-07-01

    Full Text Available La administración y la planeación prospectivas, La planeación estratégica y la logística englobanlas necesidades de direccionamiento estratégico de las empresas a nivel mundial. Estos tres elementos  actúan como un trípode. Es decir, si falta uno de ellos no podrá haber estabilidad. La prospectiva aporta el análisis y construcción de escenarios futuros además del análisis de actores. La planeación estratégica (unida a la prospectiva permite el análisis de las variables internas y externas para formular los propósitos (misión, visión, objetivos y metas, las estrategias, los planes de acción y los indicadores de desempeño y logro, tanto para la empresa en su totalidad como para cada área de la misma en particular. Finalmente, la logística permite agregar valor e integrar los procesos transversales de la empresa, ya que se ocupa del mejoramiento de actividades desde la compra de materias primas o insumos hasta la distribución y el servicio al cliente en actividades de postventa. En este artículo, se presentan los hallazgos centrales de la investigación exploratoria sobre planeación prospectiva, estratégica y logística. Dicho estudio se concentra en una muestra de 29 empresas del sector de alimentos de Bogotá (19 empresas de lácteos y 10 de conservas y aplican una metodología de estudio de caso e Investigación y acción a cuatro empresas. El análisis de esta muestra empresarial y la revisión Bibliográfica realizada sentaron las bases para el diseño de la guía y la herramienta de mejora continua en estrategia, que forma parte de la caja de herramientas, fruto del trabajo del grupo PyMES, EAN durante el último año.

  7. Mecanismos y herramientas para redes de brainstorming

    OpenAIRE

    Brene Artázcoz, Óscar

    2010-01-01

    Este proyecto propone desarrollar herramientas basadas en tecnología Web2.0 para mejorar el proceso creativo, especialmente en su fase de generación de ideas. Se pretende diseñar un conjunto de herramientas que faciliten y automaticen en cierto modo el proceso de generación de ideas y el subsiguiente proceso de agrupación de participantes de la mejor manera posible en relación a las relaciones que se hayan dado entre ellos durante el proces...

  8. Cliente ligero de Plastic SCM para tabletas

    OpenAIRE

    Luis Para, Sergio

    2016-01-01

    El Software de Control de Versiones se ha convertido, desde su aparición, en una herramienta fundamental para la gran mayoría de desarrolladores, en cuanto a que permite no sólo mantener versiones de un fichero, sino ser capaz de revisar cómo ha cambiado este a lo largo del tiempo. Entre la gran cantidad de software de control de versiones que existe actualmente (algunos software libre y gratuito, como Git o Subversion, y otros propietarios, como Perforce), se encuentra, desde finales del ...

  9. PARA EVITAR LA CONTAMINACIÓN AMBIENTAL

    Directory of Open Access Journals (Sweden)

    F Pachón

    2005-01-01

    Full Text Available El presente artículo se enmarca dentro de la caracterización del sistema de producción bovina del municipio de Utica (Cundinamarca y dentro de los problemas más importantes que lo afectan. Como resultado, el estudio identificó la escasez de alimento de buena calidad en épocas secas como la principal limitante del productor bovino del municipio. Aprovechando una ventaja presente en la zona, como es la elaboración de panela (proceso a través del cual resultan algunos subproductos, como bagazo y melote, que pueden ser utilizados como alternativa alimenticia para los bovinos en cualquier época del año, se planteó un experimento en el que se elaboraron bloques multinutricionales con base en dichos subproductos. El experimento se adelantó en una finca de un productor y se utilizaron 57 novillos cebús con edades entre los 11 y los 24 meses y pesos entre los 124 y los 463 kilogramos. Los animales se dividieron dos grupos que se mantuvieron en pasturas no manejadas. Al grupo experimental se le ofrecieron adicionalmente bloques multinutricionales. Los animales fueron examinados para comprobar su estado fisiológico, con el fin de determinar posibles inconvenientes sanitarios que pudieran afectar el ensayo. Se realizaron pesajes para medir las ganancias de peso en los dos grupos. Los resultados mostraron promedios de ganancias diarias de peso similares a Pr < 5%, donde fueron ligeramente superiores las del grupo alimentado con los bloques multinutricionales (0,848 vs. 0,769 kg animal/día. Los aportes más importantes del experimento fueron, primero, brindar una opción para que el productor pueda alimentar a sus animales en épocas de escasez y evitar que tenga que venderlos a bajos precios. El segundo aporte fue abrir la posibilidad de usar los productos de la elaboración de la panela, que en muchas ocasiones se convierten en desechos que no son usados y que contaminan las fuentes de agua, de una forma económicamente viable.

  10. Factorización para invidentes

    OpenAIRE

    Ramirez, Natalia; García, Carolina; Gutiérrez, Claudia

    2008-01-01

    Planteamos la utilización de la Áreas Mágicas, un material didáctico para la factorización de polinomios que consta de figuras geométricas (cuadrados y rectángulos) de ciertas dimensiones que, dispuestas de la forma correcta, proporcionan al educando la opción de deducir las expresiones utilizadas en los llamados “casos de factorización” sin recurrir a la memorización. Esto facilitaría un aprendizaje significativo de dicha temática sin caer en la rutina de solucionar un gran...

  11. Liderazgo Directivo: Claves para una Mejor Escuela

    OpenAIRE

    Anderson,Stephen

    2010-01-01

    El propósito de este trabajo es presentar los avances en el conocimiento acumulado respecto del liderazgo educativo a nivel de establecimientos educacionales. Se señala y describe la relevancia del liderazgo directivo en el desarrollo de cambios y mejoras educativas; las sendas de influencia; y las categorías de prácticas del liderazgo efectivo. Este trabajo propone cuatro desafíos para la implementación de prácticas: la concreción de acciones en contextos específicos, la descripción de la na...

  12. Razonamiento algebraico elemental: propuestas para el aula

    Directory of Open Access Journals (Sweden)

    Walter F. Castro G

    2014-09-01

    Full Text Available En este artículo se aborda el problema de la enseñanza de álgebra en la escuela primaria. Se discute lo que se entiende como “early álgebra” y se presentan varios enfoques sobre la introducción del álgebra en la escuela elemental. En correspondencia con los enfoques, se discuten tanto algunas tareas de razonamiento algebraico elemental que pueden ser implantadas en el aula, como algunas de las características algebraicas atribuidas. Finalmente, se presenta una propuesta para asignar niveles o grados de algebrización a algunas tareas.

  13. Publicidad, medio para crear una ventaja competitiva

    OpenAIRE

    Leyva Mancera, Jose Luis

    2014-01-01

    El caso muestra la manera en que surge una capacidad dinámica de reacción de la empresa líder del mercado en el sector automotriz en Colombia. GM Colmotores, genera estrategias para responder a los cambios, oportunidades y retos del mercado y los competidores. Así mismo se muestra la flexibilidad y evolución de la empresa que durante los últimos años siempre ha estado con la mayor porción de mercado en la industria. El desarrollo del caso permite ver como por medio de la capacidad de diri...

  14. CONTROL PREDICTIVO HIBRIDO PARA FLOTACION DE MINERALES

    OpenAIRE

    PUTZ DE LA FUENTE, EDUARDO IGNACIO

    2014-01-01

    La minería es el sector de mayor actividad en la economía nacional, posicionando a Chile como el mayor productor y exportador de cobre a nivel mundial. Sin embargo, aún existen grandes desafíos que buscan mitigar el aumento en los costos de la energía y la disminución de las leyes de mineral, así como la promoción de nuevas tecnologías. Bajo este contexto, las tecnologías de automatización se presentan como una alternativa viable y necesaria para aumentar la productividad y confiabil...

  15. NUEVAS CITAS DE ASCLEPIADACEAE PARA ARGENTINA

    Directory of Open Access Journals (Sweden)

    Sergio A Cáceres Moral

    1989-01-01

    Full Text Available Dos especies no mencionadas anteriormente de la Argentina son tratadas e ilustradas: Oxypetalum molle Hook. et Arn. y Oxypetalum ineanum Fourn. Oxypetalum appendieulatum Mart. et Zucc., Oxypetalum confusum Malme, Oxypetalum jörgensenii Meyer, Oxypetalum microphyllum Hook. et Arn., Oxypetalum pannosum Decaisne, Oxypetalum stipatum Malme, Funastrum flavum (Decaisne Malme y Blepharodon lineare (Decaisne Decaisne se registran por primera vez para la flora de Corrientes ..

  16. Yúmari / Tutuburi: danzar para no morir

    Directory of Open Access Journals (Sweden)

    Ángel Acuña Delgado

    2010-01-01

    Full Text Available Los rarámuri, habitantes de la sierra Tarahumara, al norte de México, tienen en su diversidad dancística una de sus más genuinas formas de expresión y comunicación, danza orientada tanto hacia el culto divino como hacia las relaciones humanas. Apoyado en los datos obtenidos durante los once meses de trabajo de campo entre 2001 y 2005 en varias comunidades rarámuris de la Alta y Baja Tarahumara, centraremos aquí la atención en el yúmari / tutuburi, ritual festivo a la vez que modalidad de danza desarrollada en su transcurso. Tras las referencias históricas iniciales, se describe a continuación el proceso festivo en general y la danza en particular identificada como yúmari / tutuburi; para situarnos finalmente en torno al sentido, tanto en un plano funcional como estructural. Con todo ello destacaremos la importancia que esta manifestación cultural posee para seguir siendo rarámuri dentro del contexto actual.

  17. UMA NOVA PRIMAVERA PARA A IGREJA

    Directory of Open Access Journals (Sweden)

    Marcelo Barros

    2003-01-01

    Full Text Available Nos últimos anos, as Igrejas cristãs vivem um tempo especial de abertura espiritual e humana. Tudo começou por um profundo diálogo com a humanidade. No caso das Igrejas evangélicas e ortodoxas, reunidas no Conselho Mundial de Igrejas, a sua assembléia geral teve como tema “Faço novas todas as coisas” (Ap 21,5. No caso da Igreja Católica, como mandou o Concílio Vaticano II, ela tem procurado renovar “até costumes veneráveis e ancestrais” para adequar-se à humanidade de hoje. Todos, tanto as pessoas favoráveis a este processo, como as que não concordam, percebem a vitalidade espiritual e o empenho com que toda a Igreja, fieís e pastores, confronta sua vida com o Evangelho de Jesus Cristo e se empenha na missão de testemunhar não a si mesma, mas o Reino de Deus. Nos meios de comunicação, entre as pessoas que são para a humanidade referência de autoridade ética e promotores de solidariedade e da paz estão muitos bispos e pastores dos países pobres do mundo.

  18. O preparo para o trabalho de risco

    Directory of Open Access Journals (Sweden)

    Yone Caldas Silva

    Full Text Available A autora focaliza a importância da preparação psicológica e profissional dos trabalhadores, para enfrentarem os riscos do trabalho, no cenário atual de mudanças nas organizações. Considerando a literatura científica internacional, apresenta dados de sua experiência pessoal. A partir do diagnóstico organizacional, sob a coordenação da Assessoria em Segurança, Saúde e Meio Ambiente, da Refinaria Duque de Caxias, (RJ , da qual era consultora, foi aplicada uma metodologia baseada na autonomia de ação de grupos de empregados, incluindo decisões na aplicação de recursos. Como resultados, são evidenciados a dinamização da estrutura organizacional, mudanças nas condições de trabalho, diminuição significativa nos índices e na gravidade dos acidentes, maior capacitação psicológica e profissional para o trabalho de equipe e o desenvolvimento de aptidão gerencial. Conclui, focalizando o importante papel das instituições vinculadas à segurança, saúde e meio-ambiente, indicando a necessidade de serem implementadas pesquisas de novas metodologias concernentes aos aspectos psicológicos do trabalho.

  19. Modelo alternativo para la sostenibilidad empresarial

    Directory of Open Access Journals (Sweden)

    Fausto O. Maussa Pérez

    2010-12-01

    Full Text Available Cerca de 11.000 empresas se liquidaron en todo el país durante los primeros cuatro años de la década de 1990. En este artículo se busca establecer, mediante un estudio cualitativo que emplea el método de caso, que existen alternativas para las empresas que salen de un proceso de liquidación o reestructuración: ese modelo sería la autogestión. Además, se describe un caso donde se muestran las principales características culturales, administrativas y de gestión que tienen las organizaciones autogestionadas. A partir del diagnóstico de los elementos esenciales de estas empresas, se caracterizaron varios casos de estudio: Cales y Derivados de La Sierra S.A. CALDESA; Laminados y Derivados, Layder (casos se presenta como ejemplo; Minera Las Brisas; Cooperativa Los Guaduales, en Antioquia; Artgrancol y Calzado La Corona, en Bogotá. La constitución de las empresas autogestionadas por los trabajadores representa una oportunidad para la conservación de unidades productivas, las cuales generan empleo y contribuyen a mejorar la calidad de vida de esos trabajadores y la de sus familias.

  20. importancia para la enseñanza

    Directory of Open Access Journals (Sweden)

    Concepción González Rodríguez

    2014-01-01

    Full Text Available En este trabajo se realiza una revisión histórica, de aquellos estudios/experiencias relacionados con los procesos de fotosíntesis y respiración que contribuyeron a la desestimación de la “teoría del humus” como modelo de nutrición vegetal. También se incluyen aquellos problemas que preocupaban a los investigadores en ese marco histórico. Se pondrá especial énfasis en la evolución de la formulación de “la fotosíntesis”, ya que en dicho conocimiento se localizó “la clave” que otorgó a los vegetales una importancia vital para la supervivencia de la vida en nuestro planeta. La evolución del conocimiento en ese campo, permitió pasar de un modelo de nutrición vegetal centrado únicamente en el nivel organismo, a la elaboración y aceptación del modelo actual que contempla la nutrición en tres niveles: organismo, celular y ecosistema. Finalmente se muestra la importancia que esta revisión histórica tiene para la enseñanza de este tema.

  1. para la intervención

    Directory of Open Access Journals (Sweden)

    Lina María Parada Muñoz

    2006-01-01

    Full Text Available Los problemas de fertilidad y concepción han sido tratados habitualmente en sus dimensiones biomédicas. Sin embargo, estos problemas reclaman cada día mayor intervención de equipos interdisciplinarios que permitan una atención integral, pues la imposibilidad de concepción no sólo está asociada a limitaciones biofísicas. Este artículo se desarrolla en torno a tres cuestiones: la primera, sobre la infertilidad, su dimensión biomédica y las aproximaciones que ha propuesto la Psicología para comprender las implicaciones de este fenómeno; la segunda, sobre la pareja, resaltando las posturas orientadas a discernir su naturaleza, sus formas de funcionamiento y las condiciones que las mueven al cambio; la tercera, relacionada con la narrativa como posibilidad para comprender e interpretar los fenómenos clínicos, entre ellos, las experiencias de las parejas en procesos de fertilidad asistida.

  2. Una matriz de contabilidad social para Asturias

    Directory of Open Access Journals (Sweden)

    Margarita Argüelles

    2003-01-01

    Full Text Available Una Matriz de Contabilidad Social es un sistema integrado de cuentas que presenta en un cuadro de doble entrada todas las transacciones que tienen lugar en una economía entre sectores productivos, factores de producción, sectores institucionales y resto del mundo. En comparación con una Tabla Input-Output, ofrece una mayor cantidad de información y presenta de forma plena el proceso circular de la renta, captando con mayor precisión los efectos de cambios exógenos. Una de las principales utilidades de una Matriz de Contabilidad Social es servir como base de datos para el desarrollo y aplicación de un modelo de equilibrio general computable. Este es, precisamente, el objetivo último que se persigue con la elaboración de la Matriz de Contabilidad Social de la economía asturiana que aquí se presenta. Esta Matriz ha sido construida con datos procedentes de las Cuentas Regionales de Asturias correspondientes al año 1995 y su estructura se ha adaptado a su futura utilización como base de datos para el modelo que se pretende aplicar en esta economía regional.

  3. Adolfo Celi, um olhar para dois mundos

    Directory of Open Access Journals (Sweden)

    Alessandra Vanucci

    2002-11-01

    Full Text Available O ensaio resgata a vivência brasileira de Adolfo Celi, ator e diretor italiano ativo em cinema e teatro (1922-1986, inserido no laboratório paulista da renovação, na década de 1950. Sua atuação impôs, no palco, o legado texto-cêntrico de Sílvio d'Amico e a utopia do ator plástico de Copeau e, na tela, a estética neo-realista associada a uma atuação fortemente marcada pelo ideário teatral moderno. As intuições, a herança, as oportunidades e as invenções perdidas desta experiência transcultural sugerem um quadro de realização somente parcial do projeto modernizador. Ao entrar na década de 60, é a sensação de ter esgotado um ciclo existencial que fornece a Celi um válido álibi para o retorno. Álibi (1969, seu terceiro e último filme como diretor, realizado na Itália com Gassmann e Lucignani, é um testemunho de vida e memórias, de raiva e de saudade do Brasil; e um precioso guia para entender sua extraordinária ‘aventura americana’.

  4. para cemento pórtland I

    Directory of Open Access Journals (Sweden)

    OLGA ISABEL RESTREPO BAENA

    2007-01-01

    Full Text Available En esta investigación se usaron minerales de origen colombiano tal y como son producidos en sus respectivas minas. Se experimentó con la fluorita (Santander, el feldespato (Antioquia y el manganeso (Antioquia en cantidades del 0,0%, 0,2%, 0,5%, 1,0%, 1,5% y 2,0%. Se aplicaron varias técnicas como difracción de rayos X, fluorescencia de rayos x, microscopía electrónica de barrido y microscopía óptica para caracterizar los materiales utilizados y análisis térmico diferencial para determinar la temperatura de clinkerización y se evaluó mineralógicamente el clínker obtenido. Se encontró que el mejor resultado se logró con la adición de 0,5% de la fluorita al permitir la mayor formación de alita y la disminución en el contenido de cal libre. El feldespato y el manganeso (braunita utilizados no tuvieron un comportamiento apropiado.

  5. EDUCACIÓN PARA EL CONSUMO

    Directory of Open Access Journals (Sweden)

    J. L. Castillejo

    2011-01-01

    Full Text Available El consumo es un fenómeno de gran peso en la vida actual de los países desarrollados y también de los que están en vías de desarrollo, sinónimo de felicidad y de estatus personal. Por todo ello el consumo merece ser objeto de la educación. En la educación para el consumo resulta clave la implicación familia- escuela, puesto que los padres marcan las primeras pautas en este terreno, junto al contexto social y los medios de comunicación. La educación para el consumo implica información, capacidad de análisis crítica de las situaciones y sensibilidad respecto a las consecuencias del consumo desmedido, que pone en peligro la supervivencia misma del planeta. El consumo se enfrenta así con la escala de valores que la educación debe defender.

  6. Un modelo SETAR para el PIB colombiano

    Directory of Open Access Journals (Sweden)

    Vivas Lorena

    2010-08-01

    Full Text Available En este artículo se estudia el comportamiento de la tasa de crecimiento del PIB colombiano entre 1982-2008 a partir de un modelo SETAR (Self-Exciting Threshold Autoregressive, empleando la metodología propuesta por Tsay (1989 y Tong (1990 para la detección de no linealidades relacionadas con la existencia de regímenes cambiantes. Adicionalmente, se comparan los pronósticos generados con los obtenidos en un modelo autorregresivo lineal para diferentes horizontes de predicción, empleando funciones de pérdida simétricas. Los resultados muestran evidencia empírica de que existe no linealidad de umbral en la serie asociada a las altas o bajas tasas de crecimiento registradas por su rezago anual (permaneciendo más tiempo en el régimen de tasas de crecimiento más elevadas y que el desempeño de los pronósticos del modelo SETAR parece no mejorar con respecto al modelo base.

  7. Sistema integral para viviendas unifamiliares -SIVIM-

    Directory of Open Access Journals (Sweden)

    Drágula, Josef

    1984-07-01

    Full Text Available The Integral System for Multi-family Housing —SIVIM— is a proposition combining a structural solution and a functional one. In the first, techniques developed in civil construction for reinforced concrete technology are incorporated in the production of buildings. The second one proposes a spatial solution appropriate to the users’ requirements. Thus, with this proposition, the aims of constructing mass, low-cost housing are maintained in countries with tropical climatesEl Sistema Integral para Viviendas Multifamiliares —SIVIM— es una proposición que combina una solución estructural y una solución funcional. En la primera, se incorporan técnicas desarrolladas en la construcción civil, para la tecnología del hormigón armado, a la producción de edificaciones. La segunda, propone una solución espacial apropiada a los requerimientos de los usuarios. Se mantiene así con esta proposición, las metas de la construcción masiva y del bajo costo de la vivienda en países de clima tropical

  8. Tratamiento acortado estrictamente supervisado para tuberculosis pulmonar

    Directory of Open Access Journals (Sweden)

    Alvarez-Gordillo Guadalupe del Carmen

    1998-01-01

    Full Text Available Objetivo. Evaluar la posibilidad de aplicar el tratamiento acortado estrictamente supervisado (TAES en el Programa de Control de la Tuberculosis en Chiapas, México. Material y métodos. Se evaluó la eficacia y la eficiencia del tratamiento en una cohorte de pacientes con tuberculosis pulmonar confirmada por baciloscopía, que ingresaron a tratamiento con esquemas de autoadministración semisupervisión y estricta supervisión, de enero a junio de 1996. Resultados. La eficacia fue de 90.9. 97.7 y 100% para los esquemas de tratamiento autoadministrado, semisupervisado y TAES, respectivamente, mientras que la eficiencia fue de 68.1. 77.6 y 88.5% en el mismo orden. Conclusiones. Para la salud pública el TAES demostró ser la actividad más importante en el control de la tuberculosis, al elevar las tasas de curación y disminuir, por lo tanto, las fuentes de transmisión de la enfermedad.

  9. para el mejoramiento de sus propiedades

    Directory of Open Access Journals (Sweden)

    Kelly Gallego

    2006-01-01

    Full Text Available El polipropileno (PP presenta baja resistencia al impacto a bajas temperaturas y es muy sensible a la degradación térmica. De otro lado, el polietilentereftalato (PET es un polímero muy higroscópico. Uno de los caminos para superar estos inconvenientes consiste en mezclar ambos polímeros logrando su compatibilidad mediante la inserción de grupos funcionales polares en el PP. En la presente investigación se estudió el efecto de la inserción de anhídrido maleico en el PP reciclado para la obtención de una mezcla con PET reciclado. El grado de inserción se cuanti- ficó mediante el índice de carbonilo utilizando espectrofotometría infrarroja con transformadas de Fourier, FTIR. Las mezclas de PP injertado y no injertado con PET reciclado fueron preparadas por reometría de torque y su compatibilidad se analizó por microscopía electrónica, SEM y calorimetría diferencial de barrido, DSC. Se midieron también algunas propiedades de las mezclas como dureza y absorción de agua. Se concluyó que la mejor compatibilidad se presentó en las mezclas preparadas con PP injertado.

  10. Heidegger para a Bioética

    Directory of Open Access Journals (Sweden)

    Julio Cabrera

    2014-01-01

    Full Text Available Dentro del actual panorama de crisis global, se intenta poner en discusión la propuesta del filósofo Martin Heidegger, que puede modificar la formulación de una buena parte de las cuestiones bioéticas. El filósofo presenta una nueva noción de lo humano, no solo como “persona” o “agente racional”. Según el concepto del Dasein, la modernidad fue construida en torno a tres ideas: el sujeto como centro y fundamento, la ciencia como criterio único de verdad en el progreso y su consecuente tecnificación del mundo; habría que liberar un espacio para otro tipo de creación que no excluya la técnica, pero que tampoco la exalte hasta el punto de que lo demás desaparezca. Heidegger puede ser extremadamente instigante en cuanto a la distinción salud-enfermedad y problemas como la medicalización, en el intento de obtener una noción existencial de estos conceptos, superando su visión metafísica tradicional. La salud entonces deja de ser un acontecimiento objetivo para transformarse en un proyecto existencial.

  11. Synthesis of calcium-phosphate and chitosan bioceramics for bone regeneration

    Directory of Open Access Journals (Sweden)

    MELLATIE R. FINISIE

    2001-12-01

    Full Text Available Bioceramic composites were obtained from chitosan and hydroxyapatite pastes synthesized at physiological temperature according to two different syntheses approaches. Usual analytical techniques (X-ray diffraction analysis, Fourier transformed infrared spectroscopy, Thermo gravimetric analysis, Scanning electron microscopy, X-ray dispersive energy analysis and Porosimetry were employed to characterize the resulting material. The aim of this investigation was to study the bioceramic properties of the pastes with non-decaying behavior from chitosan-hydroxyapatite composites. Chitosan, which also forms a water-insoluble gel in the presence of calcium ions, and has been reported to have pharmacologically beneficial effects on osteoconductivity, was added to the solid phase of the hydroxyapatite powder. The properties exhibited by the chitosan-hydroxyapatite composites were characteristic of bioceramics applied as bone substitutes. Hydroxyapatite contents ranging from 85 to 98% (w/w resulted in suitable bioceramic composites for bone regeneration, since they showed a non-decaying behavior, good mechanical properties and suitable pore sizes.Compósitos biocerâmicos foram obtidos a partir de pastas de quitosana e hidroxiapatita, preparadas a temperatura fisiológica seguindo dois métodos diferentes de síntese. As técnicas analíticas usuais (Análise de difração de raios-X, Espectroscopia de absorção no infravermelho com transformada de Fourier, Análise termogravimétrica, Microscopia eletrônica de varredura, Análise por energia dispersiva de raios-X, e Porosimetria foram empregadas para caracterizar o material resultante. O objetivo deste trabalho foi estudar as propriedades biocerâmicas das pastas relativas ao comportamento de não-desintegração dos compósitos de quitosana-hidroxiapatita. A quitosana, que também forma um gel insolúvel em água na presença de íons cálcio, e tem mostrado possuir efeitos farmacologicamente ben

  12. Centro para reuniones, en Karpfenberg, Estiria (Austria

    Directory of Open Access Journals (Sweden)

    Windbrechtinger, W.

    1965-03-01

    Full Text Available The building bas two wings. One of them has two storeys, and a semibasement, and is used as offices. The other wing has a single floor level, and constitutes the Meeting Hall. On entering there is a kind of forecourt, and behind the meeting hall there is a further court, which on special occasions could also be utilized for large meetings. Amusement rooms for television and card and other games are provided in the semibasement: also a photographic laboratory, games stores, washing and boiler room. The ground floor contains the municipal library, a number of offices (an insurance company, the workers' chamber, and the association of nature's friends and rooms for the meetings of political organisations. On the second floor the syndicates have their offices, which include board room, a teaching room, three rooms for guests, the doorman's living quarters, and the necessary services. Finally, the meeting hall section involves a vestibule, the hall itself with accommodation for 300 people, a stage, cafeteria, kitchen, and other auxiliary facilities. The design of this building is rational and straightforward, and is pleasantly in keeping with the surrounding buildings and landscape.El edificio consta de dos alas: una, con dos plantas—destinadas a oficinas—y semisótano; y otra, de una sola planta, en la que está situada la sala de reuniones. Visto el conjunto desde la entrada, aparece una especie de patio delantero, dejando, detrás de la sala, un segundo patio, susceptible de ser utilizado en casos especiales, tales como grandes reuniones, etc. El semisótano agrupa las salas de esparcimiento—juego, televisión, trabajos para entretenimiento—, laboratorio fotográfico y cámara oscura, locales para guardar los utensilios de deporte, aseos, almacén y cuarto de la calefacción. La planta baja contiene la biblioteca municipal, varias oficinas— de una sociedad de seguros, de la cámara de trabajadores, de la asociación de amigos de la

  13. Construyendo nuestra felicidad para ayudar a construirla

    Directory of Open Access Journals (Sweden)

    María Rosario Fernández Domínguez

    2009-01-01

    Full Text Available A lo largo de este trabajo se ofrece una visión de la felicidad y del bienestar como un proceso, como algo a construir a través de una dinámica de desarrollo y crecimiento personal que conduzca, a través del autoconocimiento, a ser más equilibrados, serenos y capaces de disfrutar de lo que hacemos y de lo que vivimos. Analizamos qué es para nosotros la felicidad, insistiendo en que ésta no consiste en tenerlo todo, o en no tener problemas ni dificultades, que, en definitiva, no reside en el exterior sino que está en nuestro interior, resaltando que es posible conquistarla. Situándonos en la perspectiva de la psicología humanista, la conectamos con la psicología positiva, cuyos orígenes se remontan a aquella, y hacemos una breve revisión del concepto de felicidad a través de diferentes autores, representantes de la psicología humanista. Finalmente, terminamos centrándonos en la perspectiva de Personalidad y Relaciones Humanas (PRH, muy cercana a la visión rogeriana. Para Personalidad y Relaciones Humanas la felicidad se puede ir conquistando poco a poco, estando muy ligada a un proceso de crecimiento interior que conduzca a la persona a ser cada vez más ella misma, desplegando todas sus potencialidades, a no vivir pendiente del éxito social o del parecer, a lograr tener el poder sobre su propia vida, sintiéndose cada vez más libre de las ataduras externas e internas; al sentido de la propia existencia, etc. Por ello, analizamos también en qué consiste crecer y qué es lo que favorece y dificulta este proceso de crecimiento interior. Situados en esta perspectiva, defendemos que la felicidad y el optimismo ante la vida es algo que no se adquiere porque sí, o sólo porque queremos. Requiere de un profundo y prolongado trabajo interior, para conocer nuestras potencialidades y límites y poder actualizarlas y ayudar a que crezcan en nuestra vida y relaciones. Pero, para crecer en libertad, alegría, optimismo, capacidad de amar

  14. Estrategia para elevar la motivación laboral; factor imprescindible para mejorar nuestra productividad.

    Directory of Open Access Journals (Sweden)

    Reina de los Ángeles Carballé Piñón

    2015-12-01

    Full Text Available Este trabajo "Estrategia para elevar la motivación laboral; factor imprescindible para mejorar nuestra productividad" resulta de la investigación realizada para tesis de maestría; se realizó el estudio de 2 entidades, nos permitió conocer las principales posiciones que sobre motivación existen, factores que la influencian, cómo incide en el desempeño laboral y que acciones diseñar para elevarla. Las 2 entidades seleccionadas, claves en el desempeño empresarial son un centro de interfase y un centro generador de conocimientos, nuestro objetivo principal es sugerir propuestas que eleven la motivación de los trabajadores del CIGET(centro de interfase y la Universidad de Sancti Spíritus(centro generador de conocimientos por desempeñar una mejor labor y lograr así aumento de la eficacia, eficiencia y productividad; este se concreta específicamente en determinar qué factores ocasionan desmotivación en los trabajadores del CIGET y la Universidad, identificar aquellos factores que realmente motivan a estas personas, de manera individual como colectivamente y trazar una estrategia con el objetivo de elevar la motivación de los trabajadores hacia la actividad que realizan y dotar a estos de herramientas para la identificación de actitudes positivas o negativas en el ámbito laboral y cómo potenciarlas o minimizarlas según sea el caso.

  15. Preparar para el futuro: el rol del educador

    Directory of Open Access Journals (Sweden)

    Myrna A. Cuevas Ruiz

    2000-12-01

    Full Text Available El artículo aborda el problema de la educación a la luz de las esperanzas y exigencias que se le plantean y de sus posibilidades reales para responder a los retos. En este marco, ubica la figura del educador, las cualidades que deben caracterizarlo para responder a las demandas de los retos educativos y los requerimientos que, en el contexto de la profesión docente, deben satisfacerse para impulsar los cambios.

  16. QRLabel y Blackbird: 2 aplicaciones accesibles para Android

    OpenAIRE

    Mercade Aguila, Gisela

    2012-01-01

    El objetivo de este proyecto es el de realizar dos aplicaciones para dispositivos móviles con sistema operativo Android. Estas aplicaciones están ideadas para ser usadas por una persona invidente o con deficiencias visuales. El transcurso del desarrollo de cada aplicacion sirve para conocer y experimentar con diferentes herramientas que dispone este sistema operativo, y de este modo estudiar sus ventajas y limitaciones. Se presentan dispositivos y prototipos de dispositivos diseñados exclusiv...

  17. Plan de marketing para la herramienta de inteligencia artificial Parlakuy

    OpenAIRE

    Farro Flores, César Augusto; Gonzales Gaspar, Juan Francisco

    2017-01-01

    Parlakuy es una empresa tecnológica en formación dedicada a utilizar herramientas de inteligencia artificial, específicamente machine learning, en las redes sociales. Tiene por objetivo ayudar a resolver las necesidades de las empresas y personas para que puedan entender a sus clientes en redes sociales, identificar temas importantes para su estudio y tomar acciones preventivas ante un suceso o acontecimiento en tiempo real. Para esto crea la herramienta Parlakuy, que tiene el mismo nombre...

  18. Plan de marketing para un vivero de planta ornamental

    OpenAIRE

    MARCH CUBERTORET, PAULA

    2017-01-01

    [ES] Se ha realizado un plan de marketing de un vivero de planta ornamental interior en Petrés (Valencia), así como un estudio de mercado para analizar las necesidades del consumidor y proponer mejorar el posicionamiento de la empresa para finalmente aumentar las ventas de sus productos. March Cubertoret, P. (2017). Plan de marketing para un vivero de planta ornamental. http://hdl.handle.net/10251/92819 TFGM

  19. Puente mixto para ferrocarril y carretera

    Directory of Open Access Journals (Sweden)

    Harris, P. C.

    1963-10-01

    Full Text Available This new bridge, known as the West Branch, spans the course of a river, and has a double function and two superimposed decks. One of these carries the road, and the other lower one, the railway line. It has been constructed by the Dept. of Public Works of California. The structure consists of four main spans resting on reinforced concrete piles, of great height. Four rectangular holes run down their centres. The decks consist of a continuous metal framework, made up of heavy elements, some of them weighing up to 56 tons each, was assembled in the workshop in separate sections. These were then transported to the site, to be integrated within the whole structure. In the final assembly high tensile steel bolts were employed. As the piles are very high, they are of varying cross section, according to the height. The concreting was done by means of sliding formwork, and this was sufficiently wide to ensure that the concrete was at least four hours old when the formwork passed beyond its level. To carry out these operations an auxiliary tower was built up. which supported the framework carrying the concreting tub and its pouring mechanism. From this main tub the concrete was poured into others, which placed it into the various parts of the formwork. The operation of the concrete elevator, whose motive power was provided by of the plant at ground level, was controlled by telephone between the operator of the power plant and the person responsible for distributing the concrete on the top platform. To provide the finish of the surfaces left by the sliding formwork, another platform was installed, working at a level below the lower edge of the formwork, and a similar arrangement was adopted with respect to the inner formwork for the four hollows running inside the piles.El nuevo puente, llamado West Branch, que salva el profundo cauce de un río, tiene una doble finalidad y dos tableros superpuestos: uno para carretera en la parte superior y otro para una

  20. Proposta de um instrumento para avaliar eventos adversos em odontologia

    Directory of Open Access Journals (Sweden)

    Claudia Dolores Trierweiler Sampaio de Oliveira Corrêa

    2017-11-01

    Full Text Available Resumo: O objetivo deste estudo foi propor um conjunto de rastreadores para a pesquisa de eventos adversos em odontologia ambulatorial no Brasil. O instrumento foi elaborado em duas etapas: (i para construir um conjunto preliminar de rastreadores foi realizada uma revisão da literatura, a fim de identificar a composição das ferramentas de rastreamento utilizadas nas demais áreas da saúde e os principais eventos adversos encontrados em odontologia; (ii para validar os rastreadores preliminarmente construídos foi organizado um painel de especialistas empregando o método Delphi modificado. Foram elaborados quatorze rastreadores para compor um instrumento com critérios explícitos para identificar potenciais eventos adversos no cuidado odontológico, essenciais para os estudos de revisão retrospectiva de prontuários. Pesquisas relacionadas à segurança do paciente em odontologia ainda são bastante incipientes em relação às demais áreas da saúde. Este trabalho pretendeu contribuir para a investigação nesse campo. O aporte da literatura e a ajuda da expertise do painel de especialistas permitiram a elaboração de um conjunto de rastreadores para a detecção de eventos adversos odontológicos, no entanto, são necessários estudos adicionais para testar a validade do instrumento.

  1. Chitosan/hydroxyapatite scaffolds for tissue engineering manufacturing method effect comparison

    Directory of Open Access Journals (Sweden)

    Diana Marcela Escobar-Sierra

    2015-01-01

    Full Text Available La regeneración del hueso es uno de los principales retos de la medicina moderna debido a que muchas enfermedades, incluyendo los traumas y los tumores, pueden causar defectos óseos. La ingeniería de tejidos (IT es un área de investigación muy prometedora para curar estas enfermedades de los huesos, ya que permite la reconstrucción de los tejidos basados en la colonización y proliferación de las células sanas, provenientes del mismo paciente, en una matriz extracelular arti¿cial denominada plataformas o andamios. El objetivo de este proyecto fue fabricar plataformas de quitosano/ hidroxiapatita CH/HA, utilizando diversas relaciones y dos métodos diferentes para la obtención de la hidroxiapatita, en polvo (comercial e in situ , para luego comparar sus propiedades. La morfología, la composición química y las propiedades mecánicas se evaluaron por microscopía electrónica de barrido (SEM, difracción de rayos X (XRD, espectroscopia Raman y ensayos de compresión. Los andamios obtenidos presentaron una estructura porosa interconectada. Las plataformas con mejores propiedades para ingeniería de tejidos fueron las fabricadas con quitosano e hidroxiapatita in situ , debido a que su morfología era más óptima para permitir el crecimiento celular. Estos andamios cumplen los requisitos de la ingeniería de tejidos.

  2. Nave para Volkswagen en Ravenna, Italia

    Directory of Open Access Journals (Sweden)

    Epaminonda, Ceccarelli

    1965-09-01

    Full Text Available This factory hall is meant to house an exhibition, workshops, stores and offices of the Italian subsidiary of the Volkswagen firm. It is sited in an urbanized, but not yet built up, area. Its ground area is 54 by 38 m. Part of the frontage, about 36 m, is set back 8 m with respect to the remaining 18 m; the latter correspond to the part of the building occupied by the exhibition hall. As the ground is weak, it has been necessary to use piles to support the foundations. The structure is metallic, and the enclosing walls and roof consist of prefabricated panels and metals sheets. The roof contains a special chamber, where the air conditioning ducts and other services are housed. Great care has been taken over the colour patterns, both inside and outside. The type of structure and use of prefabricated panels has greatly lowered the overall cost of the building. All the foundation elements have been suitable waterproofed.Esta nave industrial está destinada a albergar los servicios de exposición, talleres, depósito y oficinas para la empresa concesionaria, en Italia, de la marca de automóviles Volkswagen. Se halla situada en una zona urbanizada, pero sin edificar, y tiene 54x38 m en planta. Parte de la fachada principal—unos 36 m—está retranqueada 8 m respecto de la alineación; los 18 m restantes corresponden al salón de exposiciones. Como el terreno es de escasa capacidad de sustentación, ha sido necesario el empleo de pilotes en los puntos de apoyo. La estructura resistente es metálica y se ha cerrado y cubierto con paneles prefabricados y placas metálicas. Los forjados de cubierta tienen una cámara que permite la colocación de conductos para el acondicionamiento. Se han cuidado mucho los colores para la estructura vista y paramentos interiores. La disposición de la estructura y el empleo de paneles prefabricados han permitido obtener costos muy favorables. Todas las partes de la infraestructura han sido debidamente

  3. Contabilidade ambiental o passaporte para a competitividade

    Directory of Open Access Journals (Sweden)

    Maria Elisabeth Pereira Kraemer

    2002-03-01

    Full Text Available Como todos os problemas ambientais provocaram grandes danos irreversíveis, que incidiram e incidem agora em todos os países subdesenvolvidos e desenvolvidos, nasce, então, como necessidade imperiosa, introduzir nos nossos sistemas econômicos a Contabilidade Ambiental, pois as organizações, até alguns anos atrás, preocupavam-se apenas com a eficiência dos sistemas produtivos. Chegamos a "era da revolução ambiental", e o ambiente não somente aparece como um conjunto de problemas relativos ao controle da contaminação, mas representa um custo no crescimento econômico. Neste sentido, o contador precisa de uma formação que se estenda além dos limites das técnicas e dos procedimentos. É necessário acrescentar o registro contábil do meio ambiente, dada a velocidade de sua afetação e a influência do mundo atual na utilização e disposição dos recursos naturais. Deve ser considerado como um dos princípios contábeis, onde é um desafio para a contabilidade. Precisa ser considerada como uma ciência contábil integrada, pois com a ciência ecológica e outras ciências são responsáveis pela natureza onde devem ser aplicados critérios de proteção ambiental, demonstrando que os recursos naturais constituem nosso principal capital. Partindo dessa premissa é que este trabalho está enfocando os seguintes tópicos: Responsabilidade Social da Empresa; A Empresa e o Meio Ambiente; Gestão Ambiental; Sistema de Gestão Ambiental; Ações para Preservar o Meio Ambiente - O Protocolo Verde, A Contabilidade, Custos Ambientais, Ativo Ambiental, Passivo Ambiental, Patrimônio Ambiental, Contabilidade Ambiental e Contabilidade Ambiental - o Passaporte para a Competitividade.

  4. FACTIBILIDAD PARA IMPLEMENTAR PLANTA PROCESADORA Y

    Directory of Open Access Journals (Sweden)

    Yesenia Johana Márquez Bravo

    2017-06-01

    Full Text Available Con el propósito de conocer la factibilidad de mercadeo, técnico, económico y financiero para implementar una planta procesadora y comercializadora de café en el marco administrativo de la Asociación 24 de Agosto; organización dedicada a la compra y venta de este grano, se desarrolló un estudio de mercado, mediante encuestas dirigidas a una muestra de la población económicamente activa de los cantones Portoviejo, Manta, Chone y 24 de mayo, pertenecientes a la provincia de Manabí; además, se realizó la observación in situ para identificar la competencia actual del café procesado, la disponibilidad de materia prima, la oferta y demanda, el proceso y la tecnología necesaria para la elaboración del café soluble, la eficiencia y capacidad técnico-financiera, y expectativas del consumidor. Con los datos obtenidos se determinó la inversión requerida, estimada en $307.871,75, la cual incluye el costo de infraestructura y capital de trabajo, financiado un 86,78% mediante préstamo y el 13,22% restante con capital propio, la planta tendrá 115 200 kilogramos en capacidad de procesamiento, tiempo de recuperación de la inversión estimado en 3 año con una tasa del 21,33%. En conclusión, los resultados del estudio técnico, económico y de mercado, donde se observa una tasa de consumo del 88%, con preferencia en la presentación soluble (96% y frecuencia de compra mensual del 68%, demuestran viabilidad de inversión en la planta procesadora de café; además de tener el potencial como fuente generadora de empleo, apoyo a la economía local, crecimiento agroindustrial y cambio de la matriz productiva.

  5. Cuatro preguntas para iniciarse en cambio organizacional

    Directory of Open Access Journals (Sweden)

    Carlos A. Acosta R.

    2002-01-01

    Full Text Available El presente artículo llega a un concepto sobre el cambio organizacional a partir de las respuestas que ofrece a cuatro preguntas: ¿Qué es lo que cambia en las organizaciones?, ¿Por qué cambian las organizaciones?, ¿Cómo cambian las organizaciones? y -entonces- ¿Qué es el cambio organizacional? Para lograr el propósito se toma como objeto a las organizaciones empresariales y se centra en las dimensiones donde se localizan los cambios, explora lo que algunos autores dicen sobre el cambio, revisa varias propuestas sobre las razones que llevan al cambio en las organizaciones, expone las modalidades en que cambian las organizaciones y, finalmente, como inferencia de lo expuesto, concluye en un concepto de cambio organizacional

  6. CUATRO PREGUNTAS PARA INICIARSE EN CAMBIO ORGANIZACIONAL

    Directory of Open Access Journals (Sweden)

    Carlos Acosta

    2002-07-01

    Full Text Available El presente artículo llega a un concepto sobre el cambio organizacional a partir de las respuestas que ofrece a cuatro preguntas: ¿Qué es lo que cambia en las organizaciones?, ¿Por qué cambian las organizaciones?, ¿Cómo cambian las organizaciones? y -entonces- ¿Qué es el cambio organizacional? Para lograr el propósito se toma como objeto a las organizaciones empresariales y se centra en las dimensiones donde se localizan los cambios, explora lo que algunos autores dicen sobre el cambio, revisa varias propuestas sobre las razones que llevan al cambio en las organizaciones, expone las modalidades en que cambian las organizaciones y, finalmente, como inferencia de lo expuesto, concluye en un concepto de cambio organizacional.

  7. Sistema Web para Programa Nacional de Telemedicina

    OpenAIRE

    Silva, Gonçalo de Oliveira Pires Dias da

    2016-01-01

    O envelhecimento continuado da população dos países desenvolvidos resulta num desequilíbrio entre o número de pessoas que necessitam de cuidados de saúde e o total de prestadores de cuidados de saúde profissionais. Para fazer frente a este problema, novas formas de abordar a prestação de cuidados de saúde têm emergido mundialmente, focando-se primordialmente na prevenção de doenças em vez de no tratamento. Paralelamente, as Tecnologias de Informação e Comunicação (TIC) têm evoluído e sã...

  8. Caso para diagnóstico

    Directory of Open Access Journals (Sweden)

    Souza Fernanda H. M. de

    2006-01-01

    Full Text Available Pseudoxantoma elástico perfurante periumbilical é distúrbio adquirido do tecido elástico, que acomete mulheres multíparas. Apresenta-se um caso dessa condição em mulher de 74 anos (G10, P10 mostrando placa amarelada de aspecto reticular com áreas constituídas por pápulas eritêmato-ceratósicas. A histologia demonstra derme reticular com fibras conjuntivas basofílicas e irregulares, além de área de hiperplasia epidérmica, com eliminação de fibras elásticas através de canal repleto de ceratina.

  9. Três tempos para as teorias

    OpenAIRE

    Munari, Ana Cláudia

    2009-01-01

    Em 1996, Heidrun Krieger Olinto reúne artigos que tematizam novas formas de escrita da História da Literatura, a que ela chama de “novas teorias alemãs”. Que cânone teórico é esse, que pretende sinalizar uma nova maneira de pensar os estudos sobre a escrita historiográfica? Este artigo analisa tais teorias sob a esteira de um novo paradigma – a queda do muro de Berlin, e as transformações que ocorrem desde a passagem de uma configuração imanentista do texto para uma concepção baseada na Estét...

  10. Garaje para la Universidad de California

    Directory of Open Access Journals (Sweden)

    Lin, T. Y.

    1964-06-01

    Full Text Available California University has constructed a two storey garage, with a prestressed concrete structure, at Berkeley. A particular feature of this building is that on the roof a soil layer, 0.45 cm in depth, has been laid, on which there is a grass lawn. The structure consists of a framework of beams, of 7.30 m span, in one direction, and 19 m in the other: this being the maximum separation of the columns in one elevation. Consequently the flooring is made of slabs spanning the shorter 7.30 m distance. The roof slab has been prestressed in two mutually perpendicular directions, hence it is practically impossible for it to develop cracks. This arrangement renders the slab watertight and implies a saving in the cost of applying waterproofing treatment. As the building is surrounded on three sides by three contention walls, advantage has been taken of this to transmit to these the horizontal thrusts due to windage and seismic forces. Most of the structural elements, excepting the flooring, have been prestressed and prefabricated at a workshop 80 Km. away from the site. Many of the constructional units have additional reinforcement, which can be post-tensioned after erection at the working site.La Universidad de California ha construido un garaje, de dos plantas, de hormigón pretensado, en Berkeley, que presenta la particularidad de utilizar la parte superior de su cubierta para colocar sobre ella una capa de tierra, de 0,45 metros de espesor, coronada por un manto de césped. La estructura resistente está constituida por un reticulado de vigas formando crujías de 7,30 m de luz y apoyos espaciados a 19 m. Por tanto, las losas que forman los forjados salvan una, luz de 7,30 m, mientras que las vigas forman pórticos de 19 m de luz máxima. La losa de cubierta se ha pretensado en dos direcciones normales entre sí y, como consecuencia de ello, al hallarse debidamente comprimida en el sentido de estas dos direcciones es prácticamente imposible la

  11. Escuela para señoritas, Inglaterra

    Directory of Open Access Journals (Sweden)

    Stillman y Eastwlck-Field, Arquitectos

    1963-02-01

    Full Text Available The object was to design part of a new building which had been seriously damaged during the war, so that the old and new parts would blend into a pleasant whole, with a capacity for 600 girls. The new designs avoid the glass box style of school buildings, and glass walls have been adopted only on the ground floor, thus giving an impression of light and airiness to what used to be a partial basement. Classrooms have been designed in a simple manner, and give the impression of conventional rooms. Simple lines and materials have been chosen throughout. Strong contrasts in the external finish have been avoided, and colours provide a relaxing background to the intensive activities of the students. A constructional feature is the use of prefabricated concrete joists and supports. Outer walls consist of brick panels filling in the space between the visible concrete framework. Ceilings are of insulating boards, and the floors are covered with linoleum. Special attention has been devoted to the hall. In this case the roof is of white gypsum, and the only features are the grills covering the fluorescent lighting. The walls of this hall are of glass, and are covered with heavy velvet curtains. A balcony with hardwood posts adds a simple and friendly feature to the building. The furniture and drapery have been carefully chosen. Camden school has a rigid tradition of individualism and fine education, and the new building has succeeded in maintaining the exclusive quality of the older parts, as well as offering an overall impression of up to date construction.El problema consistía en proyectar un nuevo núcleo para un edificio que había sido seriamente bombardeado durante la guerra, de tal modo que las partes antiguas y nuevas formasen un conjunto agradable y con capacidad para más de 600 chicas. En la nueva construcción se ha evitado el carácter de «cajas de cristal» de las nuevas escuelas ordinarias y se han empleado muros de cristal solamente en la

  12. Para tener entre manos una revista

    Directory of Open Access Journals (Sweden)

    Gabriel Giannone

    2017-12-01

    Full Text Available Consideramos importante rescatar el trabajo colectivo y acumulado que precede y sucede a la labor de intermediación académica que realiza una revista. Para ello recordamos una clásica frase prologal: el texto que usted tiene en sus manos. Con cierta ironía, porque quizás muy pocos de los lectores puedan tener entre manos y oler el papel impreso de Chasqui. Desde sus pantallas, sus tablets o sus teléfonos la intención es que se comprenda este número como un solo cuerpo. Y al mismo tiempo, como un esfuerzo colectivo. Alrededor de él están las propuestas, lecturas y análisis de cientos de autores, revisores externos y lectores.

  13. De las motivaciones para escribir historia local

    Directory of Open Access Journals (Sweden)

    Oscar Londoño Pineda

    2009-01-01

    Full Text Available El presente ensayo ofrece, a partir de la experiencia investigativa del autor y su contacto con la comunidad del municipio de Tuluá (Valle del Cauca, un balance sobre el potencial de motivaciones que se originan al escribir historias locales. El autor considera relevante las motivaciones de orden personal o familiar, las de carácter reivindicativo en torno a personajes o hechos históricos que forman parte de la memoria de una comunidad y las de orden emocional y social. Finalmente la historia local es vista por el autor como una práctica de gran utilidad para la enseñanza y aprendizaje a partir de las realidades locales.

  14. Accesibilidad digital para usuarios con limitaciones visuales

    Directory of Open Access Journals (Sweden)

    Toledo, Gabriela Alejandra

    2013-04-01

    Full Text Available El presente trabajo persigue como objetivos: recapitular y analizar los principios básicos de diseño para el desarrollo de tecnologías inclusivas; evaluar ventajas y desventajas en el uso del programa lector de pantalla (JAWS al acceder a entornos comunicacionales, desde las variables de navegabilidad, interoperabilidad, usabilidad y colaboración en la cognición; derivar sugerencias acerca del diseño de entornos de aprendizaje colaborativo, de modo de lograr una mayor efectividad de esta herramienta digital, aplicada a personas con limitaciones en la visión en diverso grado; redactar un manual complementario de orientaciones que facilite el uso de este instrumento inclusivo, aplicado a entornos de enseñanza/ aprendizaje colaborativo.

  15. La escuela inclusiva: una oportunidad para humanizarnos

    Directory of Open Access Journals (Sweden)

    Miguel López Melero

    2012-01-01

    Full Text Available En este artículo mis reflexiones las centro en el amor y la educación como fundamentos de la escuela inclusiva. Un amor sin adjetivos, basado en el respeto al otro como legítimo otro en la convivencia. Es un modo de vida que se inicia en la confianza desde la edad más temprana. Más aun, el amor es un acto de confianza. La confianza es el fundamento de nuestra convivencia. Los seres humanos nos enfermamos en un ambiente de desconfianza, manipulación e instrumentalización de las relaciones. La ausencia de amor nos deshumaniza. Vivimos en un mundo en el que se habla mucho del amor pero lo negamos, continuamente, en nuestros comportamientos y acciones. Vivimos inmersos en la cultura patriarcal. El amor, en dicha cultura, es considerado como un bien inalcanzable o, acaso, una ilusión o una esperanza. Sin embargo, debemos recuperar la vida matrística de la infancia, viviendo en el amor, amando. Es decir, respetando a las personas como legítimas personas en su diferencia, independientemente del hándicap, del género, de la etnia, religión o procedencia, en la convivencia. Sólo en el respeto y en el reconocimiento de las personas como personas radica el sentido de lo humano. Lo que constituye al ser humano como tal es la dimensión social y no lo genético. La genética es la condición inicial, es un punto de partida, no de llegada. Somos lo que somos gracias a las oportunidades que hemos tenido y no a los genes. Ahora bien, lo más humano del ser humano es desvivirse por otro ser humano y en este desvivir surge el valor ético de la educación. Por tanto, hablar de inclusión es hablar de justicia y, parece lógico, que para construir una sociedad justa sea necesario desarrollar modelos educativos equitativos que afronten con justicia los desequilibrios existentes en la misma. Para ello es imprescindible que los responsables de las políticas educativas, el profesorado y los investigadores contraigamos el compromiso moral de orientar el

  16. Fomento de responsabilidad procreativa para adolescentes

    Directory of Open Access Journals (Sweden)

    Vanegas de Ahogado Blanca Cecilia

    1995-12-01

    Full Text Available

    Se está desarrollando una línea de investigación-Docencia-Extensión que pretende, con medidas de promoción y prevención primaria, fomentar en los adolescentes un manejo responsable de su sexualidad, para contribuir en la disminución del embarazo indeseado y del aborto provocado. El trabajo se inició con un programa de atención individual y de pareja en una importante universidad colombiana; continuó con un programa de educación a grupos, utilizando técnica participativa con juegos de salón, diseñados por las investigadoras, y ha tenido aplicabilidad con estudiantes de nivel secundario, universitario, de postgrado y profesionales en educación continua. Ha sido apoyado por cuatro investigaciones.

  17. PARA UMA ÉTICA DA SUSTENTABILIDADE

    OpenAIRE

    Élio Estanislau Gasda

    2010-01-01

    Convocar a ética para o debate sobre a sustentabilidade significa integrá-la na reflexão sobre a forma de pensar e orientar nosso estar no mundo e dirigir a atenção aos fins. A dimensão ética é tão importante quanto os componentes técnicos e políticos de um ideal de sustentabilidade. Neste sentido, o ponto de vista da ética sofreu uma evolução teórica nas considerações e nos enfoques sobre o desenvolvimento humano, começando pela mudança que significou a passagem de uma ética da assistência a...

  18. Lógicas para la red

    Directory of Open Access Journals (Sweden)

    Antonia HUERTAS

    2009-09-01

    Full Text Available RESUMEN: Tim Berners-Lee y sus colegas del World Wide Web Consortium (W3C llamaron «Semantic Web» al que sería el siguiente estadio de desarrollo de la red (inevitablemente traducido al castellano como Web Semántica. La idea detrás de esta evolución de la red es extender con metadatos y reglas lógicas la red basada en el lenguaje html, con el objetivo de que la infraestructura resultante permita a las máquinas entender los datos de la red de la misma forma que los entendemos los humanos. Así, añadir lógica a la red permitiría a los ordenadores tomar decisiones, hacer inferencias y responder preguntas. En este texto se pretende revisar las lógicas que han sido propuestas para permitir esta nueva web inteligente y repasar las cuestiones teóricas y pragmáticas más importantes de la corta pero intensa historia de las lógicas para la red.ABSTRACT: Tim Berners-Lee and their colleagues of the World Wide Web Consortium (W3C called «Semantic Web» the next development of the Web. The idea behind this evolution of the Web is to extend the present network based on the HTML language with metadata and logical rules, with the aim of the resulting infrastructure allowing machines to understand Web data in the same way that human beings understand them. Thus, adding logic to the Web would allow the computers to take decisions, to do inferences and to answer questions. In this paper it is intended to revise the logics that have been suggested to allow this new intelligent Web and to revise the most important theoretical and pragmatic questions of the short but intense history of logics for the Web.

  19. PARA UMA EPISTEMOLOGIA DO ATO TEATRAL

    Directory of Open Access Journals (Sweden)

    Vera Lúcia Bertoni dos Santos

    2008-03-01

    Full Text Available O texto tem por objetivo refletir sobre o fazer teatral na perspectiva epistemológica. Como ponto de partida, apresento uma breve contextualização da questão da representação teatral, relacionando-a a outras formas de representação que se fundem e confundem na contemporaneidade. A seguir, faço referência a dois modos de compreensão do ato de conhecimento, problematizando-os por meio do conceito de “miopia epistemológica? (BECKER, 2003, deformidade de ordem conceptual que impede a visualização da dialética do conhecimento, que no caso do conhecimento teatral, é responsável pela dificuldade de compreensão simultânea do ato teatral como manifestação culturalmente produzida e como formalização simbólica do pensamento. Para explicar os problemas advindos dessa dificuldade, recorro ao exemplo da construção ou sistematização da linguagem (oral e escrita, no qual as lacunas das concepções epistemológicas usuais parecem evidenciar-se mais claramente. Para concluir, teço algumas considerações sobre o sentido da representação no teatro, e sobre o caráter transformador do ato teatral que se relacionam à perspectiva epistemológica interacionista acerca do processo de conhecimento.

  20. Modelo para la implementación de controles internos para empresas constructoras.

    OpenAIRE

    Choez Chiquito, Wilton Antonio

    2015-01-01

    La presente investigación se refiere al tema Metodología para la implementación de nuevos métodos de Control para las empresas de construcción en el Ecuador. Donde las características principales de este sector ha sido su rápido crecimiento en las últimas dos décadas, con un alto número de trabajadores de obras con bajo o ningún nivel de educación, falta de compromiso por parte de los empleados de obra por el alto nivel de rotación que puede existir debido a que las construcciones son por per...

  1. Technological properties of kaolin from Para; Propriedades tecnologicas do caulin do Para

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrando, E.; Martin-Cortes, G.R.; Esper, F.J.; Wiebeck, H.; Alves Junior, P.; Valenzuela-Diaz, F.R., E-mail: germac@usp.br [Universidade de Sao Paulo (PMT/EP/USP), Sao Paulo, SP (Brazil). Escola Politecnica. Departamento de Engenharia Metalurgica e de Materiais

    2011-07-01

    The NE of the State of Para, is notable for its large reserves of kaolin for paper. Kaolin is a mineral composed of hydrated aluminum silicates such as kaolinite and halloysite. The exploitation of these reserves to generate products with higher commercial value, especially in the industries of adsorbents and catalysts, is what motivates the continuous study of technological properties of the Amazon kaolin's. Thus, this paper presents a technological characterization of a sample of kaolin from Para State by X-ray diffraction, SEM - scanning electron microscopy and infrared spectroscopy. The results of preliminary tests indicate that the sample consists for the most part by kaolinite present in low concentrations of quartz and anatase. (author)

  2. Secadores solares - térmicos para granos y frutas para utilizarlo en zonas remotas

    OpenAIRE

    Delgado, E.; Peralta, J.; Barriga, A.

    2009-01-01

    Los objetivos principales de esta investigación son: • Dar a conocer la ventaja que tiene el uso de la utilización de la energía solar térmica para sistemas de secadores solares en la disminución de la humedad de los producto. • Valorar la importancia de la conservación energética y ambiental a través del uso de energía limpia. • Dar a conocer diseños de sistema de secado solar para alimentos, principalmente granos y frutas acorde a las características del producto, geográficas, técnicas y so...

  3. Algunas consideraciones para la reconstrucción del concepto de contabilidad para el presente siglo

    Directory of Open Access Journals (Sweden)

    Claudia Lucía Niño Galeano

    2003-06-01

    Full Text Available En este artículo se hace una reflexión sobre la posición de la contabilidad en el contexto actual, rescatando de manera general su evolución como disciplina y su transformación permanente. A partir de diversas definiciones sobre contabilidad se intenta resaltar los elementos que la determinan como disciplina y sus contenidos, los cuales deben responder o vincularse aún más con la realidad económica actual, caracterizada por la globalización y el impacto de los mercados financieros internacionales. En este contexto, la contabilidad debe ser flexible, tener la capacidad para responder en forma rápida a los cambios del entorno económico y tener las cualidades necesarias para informar objetivamente a los interesados.

  4. Educación para emprender una alternativa para el siglo XXI

    Directory of Open Access Journals (Sweden)

    Luis Gerardo Rodríguez Gómez

    2015-05-01

    Full Text Available RESUMEN El artículo describe la experiencia educativa del programa Físico- Deportivo orientado a estimular la actitud para emprender dentro de una concepción de forma integral, mediante Asignaturas de contenido Sico- físico, como parte del desarrollo curricular en Facultades de Administración de Empresas e ingeniería de Sistemas en la Escuela de Administración de Negocios (EAN. El desarrollo temático hace énfasis en un proceso orientado  a superar formas de educación encaminadas al logro de habilidades técnicas para el ejercicio de un empleo y propone desde  la educación delas conductas  motrices, modos de encausar la energía sicosomática con el fin de asimilar la incertidumbre del momento histórico que se vive en los países de lento desarrollo, para corresponder a un mundo que empuña la bandera de la diversidad, el cambio acelerado y la competencia tecnológica.

  5. Todo, para todos y gratis: coordenadas para garantizar la inviabilidad de un sistema de salud

    Directory of Open Access Journals (Sweden)

    PREGNO, Elian

    2016-07-01

    Full Text Available El presente trabajo pretende anotar el fallo de la Corte Suprema de Justicia de la Nación Argentina recaído enautos caratulados: "Asociación Civil para la Defensa en el Ámbito Federal e Internacional de Derechos c/ Instituto Nacional de Servicios Sociales para Jubilados y Pensionados s/ amparo", en febrero de 2015. En primer término, se ofrece -en apretada síntesis- una referencia al caso, esclareciendo: las partes en litigio; la pretensión de la parte actora; el medio procesal interpuesto y la secuencia seguida en las sucesivas instancias, como así también los argumentos esgrimidos en cada una de ellas. A este último respecto, cabe destacar que el máximo tribunal argentino ha sentado como doctrina que resultan procedentes las acciones de clase interpuestas con el objeto de que el Instituto Nacional de Servicios Sociales para Jubilados y Pensionados brinde cobertura integral de prestaciones a personas con discapacidad, beneficiarias de pensiones no contributivas. En segundo lugar, se presenta la integración del sistema de salud en la Argentina y una serie de conjeturas en orden a la tensa relación que exhiben la justicia y la utilidad a la hora de fundamentar los derechos humanos -en general- y el derecho a la atención de la salud en particular.

  6. Educación para emprender, una opción para el mundo en desarrollo

    Directory of Open Access Journals (Sweden)

    Luis Gerardo Rodríguez

    2015-05-01

    Full Text Available RESUMEN La búsqueda de las formas educativas para corresponder con el momento histórico que vive el mundo de hoy, ha sacudido de reformas, adecuaciones y reconversiones, la geografía de nuestros países aspirantes al desarrollo. En Latinoamérica la reforma educativa es una constante y este fenómeno implica, que como educadores estemos obligados a asumir en mayor o menor proporción, el impacto de tal explosión reformista. Construir desde el quehacer cotidiano, formas de educación para orientar de manera coherente la formación de hombres para dirigir organizaciones en el mundo  de hoy, implica general un proceso educativo acorde con la reforma de la educación superior en el macro de la apertura y globalización  de la economía, y  la cual problemática social en la que se vislumbran la inestabilidad del futuro, plasmada en la crisis de la certeza y el reto de la complejidad

  7. Polymorphism and modulation of para-substituted L-Phenylalanine

    NARCIS (Netherlands)

    Sögütoglu, Leyla-cann; Lutz, Martin; Meekes, Hugo; De Gelder, Rene; Vlieg, Elias

    2017-01-01

    The crystal structure of para-methyl-L-phenylalanine at 230 K resembles that of the para-fluorinated analogue from the literaturebut is commensurately modulated with seven molecules in the asymmetric unit (Z′ = 7). At 100 K, the superstructure loses its modulation, leading to a unit cell with Z′ =

  8. PARA'04, State-of-the-art in scientific computing

    DEFF Research Database (Denmark)

    Madsen, Kaj; Wasniewski, Jerzy

    This meeting in the series, the PARA'04 Workshop with the title ``State of the Art in Scientific Computing'', was held in Lyngby, Denmark, June 20-23, 2004. The PARA'04 Workshop was organized by Jack Dongarra from the University of Tennessee and Oak Ridge National Laboratory, and Kaj Madsen and J...

  9. para mujeres y niños vulnerables

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... a nivel global . 73. Generar confianza y crear espacio para el compromiso . 75 .... para construir sistemas de salud sólidos y han colaborado inmensamente con ..... instituciones sanitarias se ve obligado a recolectar información y a registrar ...

  10. Experimental study of para- and ortho-H3+ recombination

    International Nuclear Information System (INIS)

    Plasil, R; Varju, J; Hejduk, M; Dohnal, P; KotrIk, T; Glosik, J

    2011-01-01

    Recombination of H 3 + with electrons is a key process for many plasmatic environments. Recent experiments on storage ring devices used ion sources producing H 3 + with enhanced populations of H 3 + ions in the para nuclear spin configuration to shed light on the theoretically predicted faster recombination of para states. Although increased recombination rates were observed, no in situ characterization of recombining ions was performed. We present a state selective recombination study of para- and ortho-H 3 + ions with electrons at 77 K in afterglow plasma in a He/Ar/H 2 gas-mixture. Both spin configurations of H 3 + have been observed in situ with a near infrared cavity ring down spectrometer (NIR-CRDS) using the two lowest energy levels of H 3 + . Using hydrogen with an enhanced population of H 2 molecules in para states allowed us to influence the [para-H 3 + ]/[ortho-H 3 + ] ratio in the discharge and in the afterglow. We observed an increase in the measured effective recombination rate coefficients with the increase of the fraction of para-H 3 + . Measurements with different fractions of para-H 3 + at otherwise identical conditions allowed us to determine the binary recombination rate coefficients for pure para-H 3 + p α bin (77 K) = (2.0±0.4)x10 -7 cm 3 s -1 and pure ortho-H 3 + o α bin (77 K) = (4±3)x10 -8 cm 3 s -1 .

  11. Relojes de agua, una oportunidad para calcular integrales

    OpenAIRE

    Thiabut, Elena

    2007-01-01

    Este artículo propone una investigación sobre clepsidras (relojes de agua) para alumnos de 2º de bachillerato. El cálculo integral será la clave para descubrir cómo la geometría de los recipientes condiciona el funcionamiento de estos mecanismos milenarios.

  12. The para-petroleum industry; L'industrie parapetroliere

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    The para-petroleum industry includes societies that realize studies and installations for the deposits exploitation. This document presents the situation of the para-petroleum industry in 2001, the world investment growth of the activity, the french societies financial results and an inventory of the main operations in the amalgamation domain. (A.L.B.)

  13. Jõhvis tuleb parasürrealistide näitus

    Index Scriptorium Estoniae

    2008-01-01

    Jõhvi kontserdimajas avatakse parasürrealistide rühmituse PARA näitus "Panoraam". Osalevad Ilmar Malin (maalid), Jüri Palm (maalid), Elo Järv (nahkskulptuurid), Vello Vinn (graafika), Leonhard Lapin (akvarellid), Enn Tegova (maalid), Ahti Seppet (puuskulptuurid), Raivo Kelomees (maalid), Kristiina Viin (joonistused ja maalid)

  14. CALYPTRANTHES TRICONA (MYRTACEAE, NUEVA CITA PARA LA FLORA ARGENTINA

    Directory of Open Access Journals (Sweden)

    Sara G. Tressens

    1996-01-01

    Full Text Available Calyptranthes tricona D. Legrand (Myrtaceae es reportada por primera vez para la Argentina.  Se incluyen una descripción y una ilustración. Se presenta un clave para la identificación de las especies argentinas de Calyptranthes se da. Se discuten algunas observaciones sobre la nomenclatura C.concinna DC.

  15. O Talco deve ser utilizado para Pleurodese

    Directory of Open Access Journals (Sweden)

    Steven A. Sahn

    2001-03-01

    Full Text Available RESUMO: A pleurodese està recomendada nos den·ames pleurais malignos quando o tumor não é sensível à quimioterapia. Aprcsenta taxas de sucesso vari:lveis em parte justificadas pelos diferentes agentes e doses utilizadas, a selecção de doentes eo tipo de técnica aplicada. O talco parece ser o agente mais efi caz de pleurodese.Steven Sahn defende que o talco deve ser utilizado para pleurodese, apoiando a sua opini ao em diferentes factores:Mecanisme da pleurodese para talcagcm - o talco após contacto com as células mesoteliais promove um influxo de neutrófil os IL8 mediadus e posterior acumulação de macrófagos, diminuiçãa actividade fibrinolftica e aumento do factor de crescimento dos fi broblastos. Quando o tumor reveste uma grande area de mesotclio, a pleurodese não é tao eficaz.Eficácia - uma revisão da li teratura inglesa de I966 a 1994 constatou que u talco foi o agente mais eficaz de pleurodese, cum uma taxa de sucesso de 93%, comparada cum a da tetraciclina de 67 %, doxicicli na de 72% e bleomicina de 54%. Outras séries reve1aram uma taxa de sucesso do talco sempre superior a 91 %.Custo - o talco é pouco dispendioso e se apl icado em suspensao (“slutTy” por tubo de toracostomia ainda reduz mais os custos inerentes a uma toracoscopia 4uando se utiliza o talco em pó, aprescntando cstas duas tecnicas, taxas ue eticacia scmelhantes. Reacçãoes Adversas Minor e Major Agudas- a toracalgia e a febre são OS efcitos adversos mains frequcntes, frequcntes de todos os agentes de pleurudese. A toracalgia surge em 7% dos doentcs submetiuos a plcurodesc com talco, em 28% com a bleomicina c 40% com a dox iciclina. A tetraciclina provoca geralmente wracalgia grave. A febre surge entre I6 a 69% após talcagem não ultrapassando as 72 horas.As reacçãoes adversas graves sao raras e incluern o cmpiema. arritmia cardfaca e insufcicncia rcspiratória. Se o talco

  16. TV Móvel: onde estamos e para onde vamos

    Directory of Open Access Journals (Sweden)

    Clara-Luz Álvarez

    2010-05-01

    Full Text Available O artigo apresenta (1 as características técnicas da TV Móvel [Mobile TV] e sua diferença para o IPTV e a TV pela Internet [Internet TV], (2 as questões relativas a rede, espectro e equipamento que influenciarão o arcabouço normativo, (3 as oportunidades geradas para a TV Móvel quando da migração para a TV digital, e (4 um estudo de caso do México pertinente ao marco regulatório dos serviços de telecomunicações e de radiodifusão, aos atores do mercado, à disponibilidade de espectro, à migração para a TV digital e outras questões proeminentes para a TV Móvel.

  17. UNA PROPUESTA EVALUATIVA PARA ACTIVIDADES DE EDUCACIÓN AMBIENTAL PARA LA SOSTENIBILIDAD

    Directory of Open Access Journals (Sweden)

    Rosa M. Medir Huerta

    2016-01-01

    Full Text Available El propósito de este artículo es presentar una propuesta evaluativa para ac - tividades de educación ambiental para la sostenibilidad en el ámbito escolar ofrecidas desde entidades externas a la escuela. Para ello, se realiza una eva - luación real de un programa educativo de una administración pública que se orienta al refuerzo del currículo de educación infantil, primaria y secundaria. El objetivo de la evaluación es diagnosticar la presencia, en las actividades estudiadas, de principios clave de la educación ambiental para la sosteni - bilidad identificados por el equipo de investigación a partir de referencias internacionales. La metodología es la investigación evaluativa de programas dentro del paradigma crítico de la investigación educativa y con herramientas de tipo cuantitativo. Se utiliza, básicamente, un cuestionario expresamente diseñado que valora la presencia y la ausencia de los principios establecidos de la educación ambiental para la sostenibilidad. Los resultados nos aportan nuevas informaciones acerca de las fortalezas y las debilidades del desarrollo de actividades de educación ambiental. Se llega a una valoración cuantificada de los principios definidos en tres grupos, según su necesidad de mejora, y se determina que los principios mejor tratados en las actividades son los que se relacionan con los contenidos disciplinares más clásicos, tratados con buenos y distintos métodos didácticos. En cambio, las debilidades detectadas se refieren a aspectos cruciales de la educación ambiental tales como experimentar nuevas sensaciones, aprender a buscar información, pensamiento crítico, sentimiento de pertenencia a un lugar, trabajo en colaboración, adquirir una visión global de la realidad, y reflexionar sobre la vida cotidiana y sobre el futuro deseado.

  18. Implante de biomateriais e a consolidação óssea em cadelas submetidas à ovariossalpingo-histerectomia Influence of biomaterials on the bony consolidation in spayed female dogs

    Directory of Open Access Journals (Sweden)

    A.I. Roque-Rodriguez

    2009-10-01

    Full Text Available Avaliou-se a hidroxiapatita com alandronato e hidroxiapatita com colágeno na aceleração da consolidação óssea do rádio de cadelas adultas submetidas à ovariossalpingo-histerectomia (OSH. Utilizaram-se 14 cadelas adultas, distribuídas aleatoriamente em dois grupos: grupo-controle e grupo OSH (submetidas à OSH. Quatro meses após a OSH, as cadelas dos dois grupos foram submetidas à cirurgia para produção de uma falha óssea de 4mm de diâmetro nos terços distal e proximal do rádio. No terço distal do membro direito, foi utilizada a hidroxiapatita com alandronato e, no membro esquerdo, a hidroxiapatita com colágeno; no terço proximal, não se utilizou nenhum biomaterial. Houve retardo na consolidação das falhas ósseas nas cadelas submetidas à OSH comparadas com as não submetidas. A hidroxiapatita com alandronato acelerou o processo de reparação e, em todos os animais dos dois grupos, a densidade óssea foi significativamente maior no terço distal onde foi implantada. Os dois biomateriais apresentaram biocompatibilidade, constatada pela ausência de reação inflamatória ou outra reação indesejável.The hydroxyapatite with alendronate and hydroxyapatite with collagen were evaluated in the acceleration of the bony consolidation of adult spayed bitch radius. For that, 14 adult bitches were distributed in two groups (control and spayed. Four months after ovariohysterectomy, the groups were submitted to the surgery for production of a 4mm diameter bony flaw in the distal and proximal third regions of the radius. In the distal region of the right thoracic limb, hydroxyapatite with alendronate was used. In the distal region of the left thoracic limb, hydroxyapatite with collagen was used. Any biomaterial was used in proximal part of the limb. There was a retard in bony flaws consolidation in the spayed bitches. Hydroxyapatite with alendronate showed better result, since the place it was implanted considerably increased the

  19. Quantification of iodine in porous hydroxyapatite matrices for application as radioactive sources in brachytherapy

    Directory of Open Access Journals (Sweden)

    Kássio André Lacerda

    2007-07-01

    Full Text Available In this study, non-radioactive iodine was incorporated in two types of biodegradable hydroxyapatite-based porous matrices (HA and HACL through impregnation process from sodium iodine aqueous solutions with varying concentrations (0.5 and 1.0 mol/L . The results revealed that both systems presented a high capacity of incorporating iodine into their matrices. The quantity of incorporated iodine was measured through Neutron Activation Analysis (NAA. The porous ceramic matrices based on hydroxyapatite demonstrated a great potential for uses in low dose rate (LDR brachytherapy.Materiais cerâmicos porosos à base de compostos de fosfatos de cálcio (CFC vêm sendo estudados e desenvolvidos para várias aplicações biomédicas tais como implantes, sistemas para liberação de drogas e fontes radioativas para braquiterapia. Dois tipos de matrizes porosas biodegradáveis de hidroxiapatita (HA e HACL foram avaliadas em termos da capacidade de incorporação de iodo em suas estruturas. Resultados revelaram que as matrizes porosas a base de hidroxiapatita apresentaram alta capacidade de incorporar iodo em sua estrutura. A quantidade de iodo foi mensurada através da técnica de Análise por Ativação Nêutronica (AAN. As matrizes cerâmicas porosas à base de hidroxiapatita demostraram ter grande potencial para aplicação em braquiterapia de baixa taxa de dose (LDR - Low Dose Rate.

  20. Promover os talentos para reduzir a probreza

    Directory of Open Access Journals (Sweden)

    Enrico Novara

    2003-08-01

    Full Text Available A dimensão da pobreza, a sua distribuição regional, as diferenças do fenômeno na área rural e na cidade, são elementos de conhecimento público. A cidade brasileira mostra cotidianamente as feridas causadas pela desigual distribuição de renda e pela exclusão social: a configuração espacial do território intraurbano é o mais nítido retrato do fenômeno, que hoje representa o principal obstáculo ao desenvolvimento sustentável do país. Apesar desta evidência, os programas de redução da pobreza, desenvolvidos nos últimos anos, apresentam poucos pontos de integração com a realidade territorial. Por outro lado, a desigual distribuição de renda e a exclusão social de ampla parte da população, mesmo descrevendo detalhadamente o problema, não ajudam a identificar os pontos de partida e os elementos positivos que devem ser fortalecidos para implementar programas integrados de redução da pobreza. A história e as experiências de programas de urbanização dos últimos 25 anos podem contribuir para definir um percurso metodológico a partir das potencialidades, mesmo que adormecidas, das pessoas que vivem a situação de pobreza. Chamamos "patrimônio" o conjunto de recursos palpáveis e impalpáveis que as pessoas possuem e podem colocar em jogo para enfrentar as situações críticas que estão vivendo. Identificar e desenvolver ações que possam aumentar este patrimônio, reduzindo a vulnerabilidade das famílias, pode ser o caminho a ser percorrido. O desenvolvimento de "corpos intermediários" e de atores intermediários capazes de compartilhar necessidades e potencialidades representa uma etapa fundamental deste percurso.The dimension of poverty, its regional distribution, the differences of the phenomenon in the rural area and in the city, are widely known elements. The Brazilian city shows, on a daily basis, the wounds caused by the unequal distribution of income and social exclusion: the spatial configuration of

  1. Carriles para alta velocidad. Comportamiento en fatiga

    Directory of Open Access Journals (Sweden)

    Duart, J. M.

    2005-02-01

    Full Text Available In recent years, passanger train speed and freight train load have increased to enhance efficiency of rail road transportation. These trends have increased the severity of rail service conditions, calling for rails with greager wear resistance, strength and fatigue behavior. In the United States and Europe, track site weld rails are made entirely by alumino thermic process. This work describe the results of experimental study conducted on bending fatigue strength of plain rails and alumino thermic welded rails with preheating procedures (oxipropane and air-induced propane approved by railways authorities. Compliance with the required fatigue strength shall be ascertained by 4 point pulsating bending test in accordance with European standard by alumino thermic weld in rails. The Locati method, based in the empirical Miner's law about the cumulative damage on a fatigue tested material, allows, once known the Wohler curve of the welding process in use to settle the fatigue tensile limit at 50% with only one test. The values obtained at 2.10 cycles for plain rails (Sf = 353 MPa, oxipropane preheated aluminothermic weld rails (Sf = 225 MPa, and propane-air induced aluminothermic weld rails (Sf = 210 MPa are very similar to those resulting from test method stated in the European Standard. From our point of view and due to its ease, speediness and savings, this is the most suitable test to check the quality and compare the aluminothermic processes in use.

    En los últimos años la eficiencia de los FECC, tanto para el transporte de viajeros como de mercancías, ha experimentado un desarrollo espectacular. Ello, ha sido posible gracias, entre otros factores, a la fabricación de carriles con resistencia al desgaste, carga de rotura y resistencia a fatiga mejoradas. La soldadura de los carriles, en Europa y U.S.A. se realiza "in situ" por aluminotermia con precalentamiento de los carriles con oxipropano o propano

  2. Evaluation of an IBAD thin-film process as an alternative method for surface incorporation of bioceramics on dental implants: a study in dogs Avaliação de um recobrimento de baixa espessura processado pela deposição assistida por feixe iônico como alternativa para a incorporação de biocerâmicas em implantes dentários: estudo em cães

    Directory of Open Access Journals (Sweden)

    Paulo G. Coelho

    2005-03-01

    de hidroxiapatita, onde a dissolução desigual e a presença de uma fraca interface metal-cerâmica são problemas inerentes ao seu processamento. O propósito desta investigação foi determinar os níveis de atividade óssea total e específica a uma área (0.5 mm da superfície do implante ao redor de um implante de liga de titânio (superficie jateada seguida de ataque ácido recoberto com um filme biocerâmico de baixa espessura processado através de deposição auxiliada por feixe iônico, contra um implante de liga de titânio sem recobrimento biocerâmico em cães. O modelo cirúrgico utilizou a epífise proximal da tibia, com quatro implantes colocados em cada uma, onde permaneceram por um período de 2 e 4 semanas. Oxitetraciclina (10 mg/Kg foi administrada 48 horas antes dos animais serem sacrificados. As tíbias foram dissecadas, reduzidas a blocos, e processadas para análise em microscópio ótico. Microfotografias com aumento de 20x foram obtidas da região perimetral do implante e foram alinhadas para análise da resposta biológica total. Subsequentemente, quatro micro-fotografias com aumento de 40x, sub- divididas em retângulos, foram obtidas de um dos lados do implante para quantificação da área marcada por tetraciclina. Os resultados mostraram biocompatibilidade e osseocondutividade dos implantes de liga de titânio com ou sem filme biocerâmico de baixa espessura. Análise da área marcada por tetraciclina mostrou que os implantes com recobrimento apresentaram uma maior atividade óssea total e específica ao redor do implante em 2 e 4 semanas. Os valores de atividade óssea específica à área adjacente à superfície do implante foram significantemente maiores comparados aos valores obtidos em regiões afastadas dos implantes com ou sem recobrimento biocerâmico. De acordo com os resultados obtidos neste estudo, concluímos que os implantes com recobrimento biocerâmico de baixa espessura aumentaram a resposta biológica após 2 e 4

  3. Aprendizaje y conocimiento para innovar y emprender

    Directory of Open Access Journals (Sweden)

    López de Silanes, José Luis

    2011-12-01

    Full Text Available Learning and the creation of knowledge are closely related to improved competitiveness and the creation of wealth in a country, because they help to boost innovation and the development of more productive activities with higher added value by taking advantages of the opportunities offered by the new technologies. Spain, which has made a significant effort during the last 30 years and has managed not only to position itself in ninth place among the countries with the highest scientific production, but also among the major world economies, has lost momentum in recent years, which is why it needs to improve its competitive capacity. In order to achieve this, an appropriate environment must be generated through promoting the innovative capacity of all the institutions involved and improving the quality of education, as well as the conditions required for facilitating the free movement of knowledge. In this context, the Spanish university still has an important task before it in terms of improving optimization of the use made of its educational resources and scientific production, as well as the continuous updating of knowledge and promotion of the entrepreneurial ability of young university students, with the assistance of society as a whole.

    El aprendizaje y la creación de conocimiento están estrechamente relacionados con la mejora de la competitividad y la creación de riqueza de un país, porque contribuyen a potenciar la innovación y el desarrollo de actividades más productivas y de mayor valor añadido aprovechando las oportunidades que brindan las nuevas tecnologías. España, que ha realizado un importante esfuerzo durante los últimos 30 años, y ha logrado situarse entre las principales economías del mundo, ha perdido posiciones en los últimos años, por lo que necesita mejorar su capacidad competitiva. Para lograrlo, es necesario generar un entorno adecuado mediante el fomento de la capacidad innovadora de todas las

  4. Modelo óptico para acristalamientos multicapa

    Directory of Open Access Journals (Sweden)

    Machado, M.

    2010-04-01

    Full Text Available In the design phase of a glazing system, multiple laminated glass configurations may be conceived for various architectural purposes (mainly related to aesthetical issues, energy efficiency, safety and security and/or acoustic insulation. Therefore, the availability of computational simulations of optical and thermal properties of laminated glass as a function of the properties of its constituents (glass panes, polymeric films, selective coatings may be of great utility. Standardised procedures for this kind of calculations are still being prepared by CEN (European Committee for Standardization. The theoretical study of laminated glass with internal selective coatings is especially relevant due to the introduction of reflectivity within the multilayer optical system. Here, a theoretical model based on transfer matrix method and applied to multilayer glazing with external and internal coatings is presented. Simulation results are compared with UV-VIS-NIR spectrophotometric measurements.

    En el caso del vidrio laminado, dadas las múltiples configuraciones que pueden concebirse con propósitos arquitectónicos varios en la fase de diseño (estéticos, de eficiencia energética, seguridad o aislamiento acústico, principalmente, resulta de gran utilidad poder disponer de simulaciones computacionales de las propiedades ópticas en función de las propias de sus constituyentes (sustratos vítreos, láminas poliméricas y capas selectivas a la radiación solar. Los procedimientos para la determinación por cálculo de las magnitudes de caracterización óptica de este tipo de vidrios se encuentran actualmente en proceso de normalización por el CEN (Comité Europeo de Normalización. El estudio de vidrios laminados con capa selectiva interna, en contacto con la lámina polimérica, tiene un valor teórico especialmente significativo, al introducir reflectividad en el interior del sistema óptico multicapa. En este trabajo se presenta un modelo

  5. Formar melhor para um melhor cuidar

    Directory of Open Access Journals (Sweden)

    Manuela Maria da Conceição Ferreira

    2016-02-01

    Full Text Available A formação surge como uma ajuda ao desenvolvimento humano, adoptando uma posição abrangente que inclui o aluno e o próprio professor (Kohlberg e Mayer, 1972, em que o resultado obtido é menos importante do que a disponibilidade gerada durante o percurso, para que o aluno possa continuar a evoluir ao longo da vida. Esta perspectiva desenvolvimentalista, antecipava já, a tendência actual que defende que a educação deve constituir para cada indivíduo uma forma de promover o máximo desenvolvimento das suas potencialidades, através de experiências de aprendizagem de complexidade crescente. A formação não é apenas uma instância de mediação das relações formador/formando ou equipa de formadores/grupo de formandos, mas uma instância de auto-mediação do formando com o seu mundo subjectivo, mediador do grupo de formação com as suas subjectividades, mediador do grupo com um projecto de acção através do qual ele se exterioriza (Correia, 1997: 25. A qualidade do desenvolvimento e das aprendizagens do ser humano e de toda a acção pedagógica e educativa passa de uma maneira determinante pela qualidade das relações pessoais e interpessoais estabelecidas no processo de ensino/aprendizagem (Tavares, 1996. O mesmo autor (p: 83 refere que o “educador antes de mais tem de ser uma pessoa que se dirige a outra pessoa e a ajuda a dar à luz - mais e melhor que a parteira – a sua própria identidade pessoal, como ser inteligente e livre, autor e actor do seu próprio destino de uma maneira autónoma e responsável”.

  6. Terapia antiviral para VIH-SIDA

    Directory of Open Access Journals (Sweden)

    Alicia Tarinas Reyes

    2000-12-01

    Full Text Available En los últimos años, muchos agentes antivirales nuevos han sido incorporados a la quimioterapéutica. En esta revisión se resumen tanto los fármacos establecidos de años atrás como los nuevos medicamentos desarrollados para el tratamiento de individuos infectados por VIH. El AZT fue el primero aprobado en marzo de 1987, le siguió el ddl (1991, ddC (1992, d4T (1994, 3TC (1995. Luego fue aprobado el primer inhibidor de proteasa, saquinavir en diciembre de 1995, seguido de ritonavir (1996, indinavir (1996, nelfinavir (1997; además de otros inhibidores de la reverso transcriptasa como nevirapine (1996, delavirdine (1997, efavirenz (1998, entre otros. En estos momentos se siguen buscando y desarrollando nuevas terapias alternativas para esta afección. En este trabajo se exponen algunas de las características de dichos medicamentos, como son: mecanismos de acción (sobre qué enzima actúa cada uno y cómo lo hacen, el ciclo viral, dosificación, incompatibilidades y reacciones adversas.During the last years many new antiviral agents have been incorporated to the chemotherapeutics. The pharmaceuticals established years ago as well as the new ones developed to treat HIV infected individuals are included in this review. The AZT was the first approved in March, 1987, followed by ddl (1991, ddc (1992, d4t (1994, and 3TC (1995. Later, the first protease inhibitor, saquinovir, was approved in December, 1995, followed by ritonavir (1996, indinavir (1996, and nelfinavir (1997; in addition to other inhibitors of the reverse transcriptase as neviparine (1996, delavirdine (1997, and efavirenz (1998, among others. At present new alternative therapies for this affection are being searched and developed. Some of the characteristics of these dugs, such as: action mechanisms (on which enzime each of them act and how they do it, viral cycle, dosage, incompatibilites and adverse reactions are dealt with in this paper.

  7. Hydroxyapatite crystal deposition disease: imaging aspects and biological behavior; Doenca de deposito de hidroxiapatita: aspectos por imagem e comportamento biologico

    Energy Technology Data Exchange (ETDEWEB)

    D' Aquino, Danilo Olavarria; Pinto, Alexandre de Lavra; Costa, Mauro Jose Brandao da; Fanelli, Vania A. [Hospital Sao Francisco, Ribeirao Preto, SP (Brazil)]. E-mail: documenta@netside.com.br; Abud, Lucas Giansante [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Medicina

    2005-04-15

    Objective: to demonstrate, using imaging methods (x-ray, computed tomography (CT), magnetic resonance imaging (MRI) and ultrasound (US), the phases of hydroxyapatite crystal deposition disease in joints, particularly in the shoulder, from the silent phase to the intra-osseous migration of calcifications and radiologic follow-up examinations showing complete remission after physical therapy. Material and method: we evaluated 27 joints (25 shoulders, one hip and one elbow) of patients followed-up with radiographs. Patients extremely symptomatic and refractory to treatment were referred to MRI or US. Results: total remission of calcifications was observed in 15 joints after treatment - 14 shoulders and one elbow. In two joint, migration of the calcification to bone was observed: one to the bursa subdeltoidea, one to biceps tendon, one to subcoracoid recess and one to the interior of the infra spinal muscle. In two cases MRI and CT scans showed a high inflammatory process triggered by the disease. Conclusion: hydroxyapatite crystal deposition disease affects multiple joints and can vary from asymptomatic to extremely symptomatic. Imaging methods show all phases of the disease, including the migratory phase. In general, the use of x-ray is enough for the diagnosis and follow-up. MRI and CT provide a more accurate diagnosis in the active phase of the disease. In this paper, remission was seen with physiotherapy (iontophoresis) in 55% of the cases. (author)

  8. Saturation of the hydroxyapatite mineral phase using radioactive fluorine; Saturacion de la fase mineral hidroxiapatita utilizando fluor radiactivo

    Energy Technology Data Exchange (ETDEWEB)

    Flores de la Torre, J.A.; Badillo A, V.E. [Universidad Autonoma de Zacatecas, 98000 Zacatecas (Mexico); Lopez D, F.A. [Unidad PET Ciclotron, Facultad de Medicina, UNAM, 04510 Mexico D.f. (Mexico)]. e-mail: ebadillo@cantera.reduaz.mx

    2005-07-01

    With the purpose of knowing the Anion exchange capacity (CIA) of the hydroxyapatite mineral phase, marketed by BIO-RAD, becomes necessary to saturate the surface of the mineral with an anion specie that possesses a strong affinity by this solid as it is the case of the fluorine. Moreover it takes advantage that offers the radioactive tracer technique, using the radioactive isotope of the fluorine, {sup 18}F, produced in the cyclotron of the UNAM. This saturation is obtained in terms of the quantity of retained fluorine (mmol/ 100 g) in the synthetic hydroxyapatite in function of the concentration of the solution of NaF that oscillates from 0.7 M up to 0.16 M to fixed values of pH of 9.2. Those results demonstrate that to this fixed pH value the saturation of the surface of the hydroxyapatite is achieved in approximately 30 mmol/ 100 g, using important concentrations of NaF that correspond to 0.14 M from now on. This result demonstrates the high capacity of the solid considered to retain considerable quantities of fluorine even to basic pH values. (Author)

  9. Obtaining hydroxyapatite coatings on titanium by the biomimetic method; Obtencion de recubrimientos de hidroxiapatita sobre titanio mediante el metodo biomimetico

    Energy Technology Data Exchange (ETDEWEB)

    Paz, A.; Martin, Y.; Pazos, L. M.; Parodi, M. B.; Ybarra, G. O.; Gonzalez, J. E.

    2011-07-01

    In this work, a study about the deposition of hydroxyapatite on a titanium substrate employing the biomimetic method is presented. A solution with high content of calcium and phosphorus (SCS) was used. In addition, activation of titanium with hydrogen peroxide and hydrochloric acid and a subsequent heat treatment was performed. The characterization of materials used and the coating obtained was carried out by Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). As a result of the activation processes a hydrated titanium oxide was formed. On the active surface, a coating of hydroxyapatite was obtained after a period of 24 h, which has a thickness of about 2-4 {mu}m. (Author) 21 refs.

  10. Synthesis and characterization of hydroxyapatite-doped silver nanoparticles; Sintese e caracterizacao de hidroxiapatita dopada com nanoparticulas de prata

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Flavio Augusto Cavadas da Silva; Rollo, Joao Manuel Domingos de Almeida, E-mail: flavio.andrade@usp.br [Universidade de Sao Paulo (EESC/FMRP/IQSC/USP), Sao Carlos, SP (Brazil). Programa de Pos-Graduacao Interunidades Bioengenharia; Rigo, Eliana Cristina da Silva; Vercik, Andres; Vercik, Luci Cristina de Oliveira; Valencia, German Ayala; Ferreira, Leticcia Gaviao [Universidade de Sao Paulo (USP), Pirassununga, SP (Brazil). Faculdade de Zootecnia e Engenharia de Alimentos. Departamento de Ciencias Basicas

    2012-07-01

    Hydroxyapatite-doped silver nanoparticles was obtained by immersing the powder in increasing dilutions of a solution containing AGNPS which were synthesized in different times and were characterized by UV-vis spectroscopy. The X-ray diffraction (XRD)studies demonstrate no change in the major phase of HA. Scanning Electron Microscopy (SEM) revealed morphological characteristics of powders after doping and the presence of silver was confirmed by energy dispersive X-ray (EDAX) analysis.The antibacterial effect of the doped powders was evaluated using strain of Staphylococcus aureus by disc-diffusion test. The zone of inhibition was found to vary with the amount of silver nanoparticle in the doped powder even for low concentrations of AgNPs. These results indicate that the method of immersion hydroxyapatite in solutions containing AgNPs is promising to obtain bioactive materials with low cytotoxicity and antibacterial effects. (author)

  11. Aditivos para hormigones, morteros y pastas

    Directory of Open Access Journals (Sweden)

    Gaspar Tebar, Demetrio

    1984-09-01

    Full Text Available This article comments on the increasing importance of the use of admixtures for concrete, mortars and grouts as well as the specific effects they produce, thus requiring a suitable Spanish Normative, whose performance was taken in charge by a Working Group of the Technical Commission n.° 83 from the IRANOR, created for this purpose. This article is first of a series which intends to give an account of the works, on the Normative of those additives, the Working Group is carrying out.

    En el presente artículo se comenta la importancia que ha adquirido el empleo de los aditivos para hormigones, morteros y pastas, así como las modificaciones y efectos específicos que producen, lo que ha motivado la necesidad de contar con una normativa española apropiada, cuya realización se encomendó a un Grupo de Trabajo, creado al efecto, de la Comisión Técnica n.º 83 del IRANOR. Este artículo es el primero de una serie en la que se pretende dar cuenta de los trabajos que sobre normativa de los mencionados aditivos se viene realizando por dicho Grupo de Trabajo.

  12. [Acute-stage para- and tetraplegia].

    Science.gov (United States)

    Hachen, H J

    1993-03-20

    A quarter of a century ago, in October 1964, the first spinal cord injury center in Switzerland was opened at Geneva University Hospital. At that time all para- and tetraplegics were classified as "high-risk" patients. Early mortality, covering the initial four weeks following trauma, was still around 15%. The available resources for diagnostic assessment were limited to clinical examination and neuroradiological assessment (subsequently improved by the introduction of tomography and gas myelography). A great many patients suffered a deteriorated neurological level due to inadequate, multiple transfers between hospitals. Most patients who are paralyzed following a road-traffic accident show severe polytrauma. Their chances of survival and functional recovery have greatly improved in recent years due to efficient emergency transport by helicopter, admission to an intensive care unit (respiratory therapy, prophylactic anticoagulation, gastrointestinal cytoprotection, prevention of pressure sores, etc.) and a comprehensive medico-surgical team approach (orthopedic surgeons, neurosurgeons, ICU specialists, internists, etc.). Evaluation of the spine and spinal cord by NMR and CT scan allows precise assessment of the extent of CNS damage and provides additional guide-lines regarding efficient surgical reposition and spinal fusion. Ongoing experimental research in neurophysiology and neurobiochemistry of the brain and spinal cord is presently yielding some interesting results which hold out new hopes for functional recovery in some specific types of incomplete spinal cord trauma.

  13. Biblioteca y residencia para estudiantes - Viena (Austria

    Directory of Open Access Journals (Sweden)

    Lippert, G.

    1972-02-01

    Full Text Available The recently completed Municipal Library of Vienna, includes the lending of books, reading rooms, information services, children's library, municipal library and lecture rooms. The hostel Adolf Schärf «Vindobona» is a tall building, of 33 m height, which in addition to many rooms for the communal life of students, has 54 double bedrooms, and 147 single rooms, equipped with standards of comfort comparable to those of an hotel, since the hostel is used by students in winter, and as an hotel in the summer.El conjunto terminado Casa del Libro-Biblioteca Municipal de Viena alberga los servicios de autoalquiler, salas de lectura, información, biblioteca infantil, biblioteca municipal, salas de conferencias, etc. La Residencia Hogar Adolf Schärf «Vindobona» es una torre de 33 m de altura que, además de los numerosos locales para el desarrollo de la vida en común de los estudiantes, alberga 54 habitaciones con dos camas, y 147 sencillas, equipadas todas ellas a escala hotelera, dado que el hogar es explotado por los mismos estudiantes como tal hotel durante las vacaciones.

  14. Fuentes documentales para la historia del CSIC

    Directory of Open Access Journals (Sweden)

    Rodríguez de Quiroga, Alfredo

    1999-08-01

    Full Text Available Not available.En la línea que desde hace tiempo vienen apuntando diversos autores, se plantea en este trabajo la necesidad de abordar del modo más exhaustivo posible la reconstrucción histórica del Consejo Superior de Investigaciones Científicas. Resulta para ello indispensable recurrir al uso de fuentes documentales reveladoras de información detallada de primera mano que permita un estudio serio y riguroso del tema. En este sentido, nuestro objetivo es contribuir a facilitar tan difícil labor, aportando con estas notas los resultados obtenidos en la primera fase del proyecto que estamos llevando a cabo sobre la localización y recuperación de los fondos que, directa o indirectamente, se encuentran relacionados con el papel desempeñado por el Consejo en el proceso de construcción y desarrollo institucional de la política científica y tecnológica en el franquismo.

  15. Guía para autores

    Directory of Open Access Journals (Sweden)

    Perspectiva Geográfica

    2016-01-01

    Full Text Available Perspectiva Geográfica es una revista académica arbitrada, de periodicidad semestral desde el 2013, especializada en estudios geográficos y de planificación territorial, dirigida a comunidades académicas, investigativas y del desarrollo territorial, interesadas en temas geográficos y ciencias afines. La publicación es editada por el programa de Estudios de Posgrado en Geografía–EPG- en el marco del convenio de colaboración científica entre la Universidad Pedagógica y Tecnológica de Colombia– UPTC- y el Instituto Geográfico Agustín Codazzi–IGAC- desde 1987 y se  encuentra indexada en Publindex, sistema de publicaciones del Departamento Administrativo de Ciencia, Tecnología e Innovación de Colombia –Colciencias–,  en Clase (Índice de Citas Latinoamericanas en Ciencias Sociales y Humanidades de la UNAM, y en Latindex (Sistema Regional de Información en Línea para Revistas Científicas de América Latina, el Caribe, España y Portugal.

  16. Guía para autores

    Directory of Open Access Journals (Sweden)

    Perspectiva Geográfica

    2016-06-01

    Full Text Available Perspectiva Geográfica es una revista académica arbitrada, de periodicidad semestral desde el 2013, especializada en estudios geográficos y de planificación territorial, dirigida a comunidades académicas, investigativas y del desarrollo territorial, interesadas en temas geográficos y ciencias afines. La publicación es editada por el programa de Estudios de Posgrado en Geografía –EPG– en el marco del convenio de colaboración científica entre la Universidad Pedagógica y Tecnológica de Colombia– UPTC- y el Instituto Geográfico Agustín Codazzi –IGAC– desde 1987 y se encuentra indexada en Publindex, sistema de publicaciones del Departamento Administrativo de Ciencia, Tecnología e Innovación de Colombia –Colciencias–, en Clase (Índice de Citas Latinoamericanas en Ciencias Sociales y Humanidades de la UNAM, y en Latindex (Sistema Regional de Información en Línea para Revistas Científicas de América Latina, el Caribe, España y Portugal.

  17. Educar para a democracia Educating for democracy

    Directory of Open Access Journals (Sweden)

    Maurício Mogilka

    2003-01-01

    Full Text Available Este artigo tem por preocupação central definir e discutir o conceito de educação democrática. Ele desenvolve a discussão baseando-se nos conceitos e reflexões da pedagogia humanista, especialmente no pensamento social de John Dewey. Nesse enfoque interacionista, entende-se a educação como um processo circunscrito socialmente e simultaneamente capaz de modificar estruturas, pela formação de novos tipos de subjetividade e pela articulação com as demais lutas sociais. Nesta direção, o artigo procura mostrar de que maneira a educação democrática aponta para experiências de formação nas quais as crianças podem estruturar a sua subjetividade de forma autônoma, sem o uso da coerção.This article's main concern is to define and discuss the concept of democratic education. This discussion is developed based on the concepts and reflections of humanistic pedagogy, especially the social thinking of John Dewey. In this interactive focus, education is understood as a socially circumscribed process, simultaneously capable of modifying structures by forming new types of subjectivity and by articulating with other social struggles. In this sense, the article attempts to show how democratic education points to formative experiences through which children can autonomously structure their subjectivity, without the use of coercion.

  18. Recomendaciones para una lactancia materna exitosa

    Directory of Open Access Journals (Sweden)

    María Elena Ortega-Ramírez

    2015-03-01

    Full Text Available La lactancia materna es la única manera de proporcionar los nutrientes ideales para el adecuado crecimiento y desarrollo de los niños y las niñas. Es el único alimento que tiene una influencia biológica y emocional sobre la salud de la madre y su hijo. La lactancia materna protege a los lactantes de enfermedades gracias a sus propiedades antiinfecciosas, además de que es de más fácil digestión por la menor cantidad de caseína. No contiene betalactoglobulina, que es la proteína que más frecuentemente se asocia con alergia a proteína de leche de vaca. Por estas razones los médicos y trabajadores de la salud deben favorecer la práctica de la lactancia materna.

  19. para celdas de combustible de etanol

    Directory of Open Access Journals (Sweden)

    CARLOS MONSALVE GIL

    2008-01-01

    Full Text Available En este trabajo se elaboraron dos membranas nanocompuestas de Nafion®- TiO2 con 2 y 4% del cerámico por el método del “recasting”. El análisis de composición del microscopio de barrido electrónico (SEMEDS mostró una estructura de dos capas, una enriquecida en cerámico y otra con menos cantidad, pero con dispersión uniforme. Se midió la velocidad de permeación de etanol y la absorción de solventes en estas membranas a diferentes temperaturas y concentraciones y los resultados fueron comparados con los obtenidos para la membrana de Nafion® sin modificar. Los resultados experimentales mostraron un incremento de la permeación y de la absorción de solvente con la concentración de etanol y la temperatura. La absorción de agua también mostró un incremento en las membranas compuestas lo cual puede permitir operar a mayores temperaturas y menores humedades relativas y aumentar el desempeño de la celda de combustible.

  20. Guía para autores

    Directory of Open Access Journals (Sweden)

    John Harold Estrada Montoya

    2015-08-01

    Full Text Available La Revista Acta Odontológica Colombiana, es una publicación electrónica seriada, semestral y arbitrada, editada desde la Facultad de Odontología de la Universidad Nacional de Colombia, dirigida a académicos, investigadores y profesionales interesados los temas actuales y los resultados de la actividad científica e investigativa en odontología. Filosofía y política editorial La Revista Acta Odontológica Colombiana tiene como objetivo publicar resultados o avances de investigación promotores del desarrollo de conocimientos académicos, técnicos, científicos y éticos para la odontología y la salud bucal, relacionados con aspectos de la práctica clínica, salud pública, bioética, educación, ciencias básicas, biotecnología, materiales dentales y de laboratorio. Asimismo tiene como propósito consolidar el intercambio de saberes, experiencias e investigadores en el área de la salud, en general, y de la odontología, en particular, a nivel nacional e internacional.