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  1. Development of procedure using plasma welding process to produce {sup 125}I seeds; Desenvolvimento de procedimento utilizando processo de soldagem plasma para confeccao de sementes de {sup 125}I

    Feher, Anselmo

    2006-07-01

    The prostate cancer, which is the second cause of death by cancer in men, overcome only by lung cancer, is a problem of public health in Brazil. Brachytherapy is among the possible available treatments for prostate cancer, in which small seeds containing {sup 125}I radioisotope are implanted in the prostate. The seed consists of a titanium sealed capsule with 0.8 mm external diameter and 4.5 mm length, containing a central silver wire with adsorbed {sup 125}I. The plasma arc welding is one of the viable techniques for the sealing process. The equipment used in this technique is less costly than in other processes. The main objective of this work was the development and the validation of the welding procedure using plasma welding process and the elaboration of a sealing routine according to Good Manufacturing Practices. The development of this work has presented the following phases: cut and cleaning of the titanium material, determination of the welding parameters, development of a device for holding the titanium tube during the welding process, validation of sealed sources according to ISO 2919 Sealed Radioactive Sources - General Requirements and Classification, leakage test according to ISO 9978 Sealed Radioactive Sources - Leakage Test Methods and metallographic assays. The developed procedure, to seal {sup 125}I seeds using plasma welding process, has shown to be efficient, satisfying all the established requirements of ISO 2919. The results obtained in this work have given the possibility to establish a routine production process according to the orientations presented in resolution RDC number 59 - Good Manufacturing Practices do Medical Products of the ANVISA - Brazilian Nacional Agency of Sanitary Surveillance. (author)

  2. Soldagem tig orbital

    Pigozzo, Ivan Olszanski

    2015-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2015. As obras de construção de tubulações e dutovias para o transporte de matéria, principalmente na indústria do petróleo e gás, apresentam na atualidade constante crescimento, causando relevantes impactos econômicos e produtivos para o desenvolvimento do país. Neste tipo de obra, as etapas de soldagem são um fator determinante para melhore...

  3. Soldagem por Difusão de Aços Inoxidáveis para Fabricação de Trocadores de Calor Compactos

    Marcus Vinícius Volponi Mortean

    2016-03-01

    Full Text Available Resumo A união de materiais diferentes ou componentes com geometrias complexas muitas vezes requer processos de uniões especiais, como por exemplo, uma fonte de energia de alta densidade como laser ou feixe de elétrons para soldagem por fusão ou mesmo um processo de soldagem no estado sólido. Em particular, este trabalho descreve os experimentos recentes da aplicação da soldagem por difusão no estado sólido (SDES para diferentes tipos de aços inoxidáveis: austenítico AISI 316L, duplex UNS 31803 e superduplex UNS 327250. A soldagem por difusão foi realizada sob alto vácuo a 1050 °C, durante 60 minutos, empregando uma pressão uniaxial de 18-35 MPa. A qualidade da união foi avaliada por microscopia óptica e testes mecânicos. Os resultados preliminares indicam a necessidade de otimização dos parâmetros de processo para os aços duplex e superduplex. Os resultados positivos alcançados no presente trabalho permitiram a fabricação de protótipos de trocadores de calor compacto em aço inoxidável, utilizando o novo método de fabricação, desenvolvido por LABTUCAL / UFSC, através do qual o processo de corte a jato de água é aplicado para confeccionar com precisão os canais do núcleo do permutador de calor.

  4. Metodologia de Baixo Custo para Registro de Imagens do Arco Voltaico de Soldagem

    Anna Louise Voigt

    2017-12-01

    Full Text Available Resumo Equipamentos que permitem o registro de imagens são importantes ferramentas no estudo dos processos de soldagem. Contudo, câmeras de alta velocidade que permitem a captura de imagens do arco voltaico e dos fenômenos envolvidos, a exemplo da transferência metálica, são limitadas devido ao seu alto custo. Tendo em visto a utilização de câmeras de baixo custo relativo, o presente estudo tem por objetivo avaliar os efeitos dos parâmetros de exposição no registro do arco voltaico, sendo este, semelhante ao que se observa através da máscara de soldagem. Logo, analisou-se os efeitos da abertura do diafragma, tempo de exposição e sensibilidade ISO. Além destes parâmetros, foram empregados filtros na lente da câmera a fim de melhorar a qualidade das imagens. Por fim, aplicou-se o conhecimento adquirido no registro do processo TIG com alimentação de arame frio, sendo possível a visualização das gotas sendo transferidas bem como da poça de fusão.

  5. Desenvolvimento e Validação de Algoritmos para Emprego de Sensores na Soldagem Robótica Orbital do Passe de Raiz de Tubulações

    Renan Medeiros Kindermann

    2015-12-01

    Full Text Available Resumo Os sistemas comerciais destinados à automação da soldagem orbital enfrentam desafios perante o controle da trajetória e a parametrização do processo. Os tubos e dutos do setor de Petróleo e Gás apresentam descontinuidades, advindas de sua fabricação, críticas para o processo de soldagem. Para superar isto, o presente trabalho investiga a utilização de sensores para correção em tempo real da soldagem orbital. Um robô antropomórfico atua na condução da tocha. Um sensor a arco para seguimento de junta e um sensor baseado no contato elétrico para procura da junta foram empregados. Um programa em forma de algoritmos para geração de uma trajetória orbital automática e alocação dos parâmetros de soldagem foi desenvolvido. A validação da estratégia proposta e do controle da tocha pelo sensor a arco foi realizada com depósitos em corpos de prova de tubos. A soldagem do passe de raiz com um processo MIG/MAG com controle de corrente no curto-circuito também foi executada em conjunto com o sensor a arco.

  6. Reciclagem de Cavacos de Titânio para a Deposição de Revestimentos Duros por Soldagem

    José Gedael Fagundes Júnior

    2015-03-01

    Full Text Available O titânio é um metal nobre e possui excelentes propriedades biomecânicas, podendo assim ser plenamente aceito pelo organismo humano. A grande demanda na utilização de implantes dentários, fabricados a partir de ligas de titânio traz consigo um aumento significativo na geração de resíduos (cavacos, resultantes dos processos de usinagem empregados. Com o objetivo de reduzir os impactos ambientais, soluções alternativas para a reutilização de tais resíduos têm sido estudadas. O carboneto de titânio (TiC possui elevada dureza, o que potencialmente permitiria a sua utilização como reforço em revestimentos antidesgaste aplicados em equipamentos das indústrias sucroalcooleira e mineradoras. Neste trabalho cavacos de ligas a base de titânio foram processados e utilizados como matéria prima para a fabricação de consumíveis experimentais de soldagem. Cordões de solda foram produzidos sobre amostras de aço-carbono por soldagem a arco elétrico com proteção gasosa e eletrodo de tungstênio (tradução do termo inglês GTAW. A caracterização microestrutural do metal de solda foi realizada por MEV e difração de raios-X. O comportamento mecânico dos revestimentos foi analisado por meio de um ultramicrodurômetro digital. Verificou-se que a microestrutura do metal de solda era composta por partículas não prismáticas de alta dureza distribuídas em uma matriz ferrítica. Medidas feitas por microanálise EDS mostraram diferenças na concentração de titânio entre a matriz e as partículas duras, onde maiores teores deste elemento foram identificados. A análise cristalográfica confirmou que houve a formação de carbonetos de titânio envoltos por uma matriz de ferrita.

  7. Aperfeiçoamento da técnica de Soldagem Pontual por Fricção (FSpW para união de poliamida 6 e laminado de poliamida 66 com fibra de carbono

    Joel Gonçalves

    2014-03-01

    Full Text Available A Soldagem Pontual por Fricção ('Friction Spot Welding - FSpW' é uma técnica inovadora que foi desenvolvida e patenteada em 2005 pelo centro de pesquisa alemão Helmholtz Zentrum Geesthacht (HZG. A técnica apresenta ciclos rápidos, baixo custo operacional e gera soldas com alto desempenho mecânico. Foi inicialmente projetada para a soldagem de ligas metálicas leves. A soldagem de polímeros é alvo de pesquisas recentes e a soldagem de compósitos poliméricos por FSpW ainda é inédita. Este estudo demonstrou a viabilidade técnica da soldagem de chapa de poliamida 6 (PA6 e laminado de poliamida 66 e fibra de carbono (CF-PA66 por FSpW. O histórico térmico, o acabamento superficial, a microestrutura da região da solda e a resistência mecânica ao cisalhamento de juntas sobrepostas PA6/CF-PA66 foram investigados. O aumento do tamanho do anel de fixação da ferramenta original, projetada para a soldagem de metais, possibilitou a seleção de parâmetros de soldagem que resultaram em grande aporte térmico, resultando no aumento da área soldada, num menor entalhe (inscrição deixado pela ferramenta na amostra, produzindo melhoria no acabamento superficial da solda. Essa otimização resultou em uma junta PA6/CF-PA66 com resistência ao cisalhamento de 35 MPa (2196 N, com fratura predominante na placa superior de PA6.

  8. Otimização de Parâmetros do Processo de Soldagem Arco Submerso para Revestimentos Anticorrosivos

    Marcos Mesquita da Silva

    2016-03-01

    Full Text Available Resumo Neste trabalho foi avaliada a influência das variáveis de soldagem em cordões de solda, aplicados pelo processo Arco Submerso (SAW com corrente convencional, visando futura aplicação em revestimentos metálicos contra corrosão. Segmentos de tubo de um aço API 5L Gr B foram utilizados como substrato, além da utilização de um metal de adição de liga de níquel, diâmetro de 1,13mm, classificação AWS ERNiCrMo-4 (Hastelloy C-276, e um fluxo do tipo neutro, básico e aglomerado (EN 760: SA AF 2 DC. Foram analisadas as variáveis tensão, velocidade de alimentação de arame e distância do bico de contato à peça (DBCP – com o restante dos parâmetros constantes – através de um planejamento fatorial completo em dois níveis e pontos centrais. Os resultados mostraram modelos matemáticos estatisticamente significativos e preditivos para as respostas diluição e corrente média, IM. Porém, para a resposta Reforço/Largura (R/L, o modelo se caracterizou como estatisticamente significativo, não preditivo e contendo uma falta de ajuste. A DBCP, por sua vez, foi a variável que se constituiu como a de maior significância na redução da diluição.

  9. Desenvolvimento dos Parâmetros do Processo de Soldagem por Atrito com Pino Não Consumível para o Aço de Alta Resistência e Baixa Liga ISO 3183 X80M

    Tahiana F. C. Hermenegildo

    Full Text Available Resumo Sabe-se que as velocidades de soldagem e rotacional, força axial, ângulo de inclinação e desenho da ferramenta são as principais variáveis de entrada independentes, que são utilizadas para controlar o processo de soldagem por atrito com pino não consumível, e que a taxa de geração de calor, taxa de resfriamento, força na direção de soldagem e o torque são as variáveis de resposta, que irão influenciar na evolução microestrutural e desempenho mecânico da junta soldada. Neste trabalho foi feito um estudo do comportamento destas variáveis visando o desenvolvimento de parâmetros para o aço API 5L X80 (ISO 3183 X80M. Para tanto, chapas com 12 mm de espessura, foram soldadas através de dois passes, utilizando ferramenta de nitreto de boro cúbico policristalino. Observou-se que, mantendo-se a velocidade de soldagem constante, o aumento da velocidade rotacional e /ou da força axial, tende a reduzir as forças reativas e o torque atuantes durante o processo pelo aumento da taxa de geração de calor. Por outro lado, mantendo-se essas variáveis constantes, o aumento da velocidade de soldagem tende a aumentar as forças e o torque, uma vez que para o aço, este parâmeto desempenha um papel significativo na taxa de geração de calor durante o processo.

  10. Proposta de roteiro para a determinação das variáveis de soldagem do Processo TIG pulsado aplicado à soldagem de chapas finas Proposal of roadmap for determining the variables of pulsed TIG welding process applied to welding of thin plates

    Tiago Vieira da Cunha

    2013-03-01

    Full Text Available Na soldagem TIG pulsada a corrente varia entre dois níveis bem definidos de energia numa determinada frequência, sendo, portanto, necessário a regulagem de um conjunto de variáveis composto pela corrente de pulso, tempo de pulso, corrente de base, tempo de base, além da velocidade de soldagem. Entretanto, apesar de ser uma técnica tão amplamente difundida, na prática estas variáveis de soldagem muitas vezes são reguladas de forma arbitrária. Isto pode conduzir ao uso ineficiente da pulsação da corrente quando considerado o resultado final da solda, bem como nos aspectos de produtividade. Diante desta carência, este trabalho tem por objetivo apresentar um roteiro desenvolvido com o intuito de suprir a necessidade prática de se estabelecer critérios para auxiliar a determinação das variáveis da soldagem TIG pulsada, tomando como premissa a largura desejada para o cordão de solda final, a sobreposição entre os pontos de solda que compõem o cordão e a velocidade de soldagem. Por fim, é apresentada uma aplicação deste roteiro na soldagem "bead on plate" de chapas de aço inox com 1,2 mm de espessura.In pulsed TIG welding the current varies between two well-defined energy levels in a given frequency being, therefore, necessary to the adjustment of a set of variables consisting of the peak current, peak time, background current, background time and the welding speed. However, despite being a technique so widespread, in practice these welding variables are often regulated arbitrarily. This can lead to inefficient use of the pulsed current regarding the end result of the weld as well as in the aspects of productivity. Given this shortage, this paper aims to present a roadmap developed in order to meet the practical need to establish criteria to assist in the determination of pulsed TIG welding variables, taking as its premise the desired width of the weld bead, overlap between the weld points comprising the weld bead and the

  11. Desenvolvimento de sistema de apoio com depósito cerâmico para soldagem e processamento por atrito com pino não consumível

    Tiago F. A. Santos

    2014-06-01

    Full Text Available A mesa suporte das peças a serem unidas normalmente se deforma durante o processo de soldagem por atrito com pino não consumível devido às altas cargas envolvidas. Consequentemente, a obtenção de juntas soldadas com penetração total, bem como a vida útil da amostra e da ferramenta podem ser afetadas, causando paradas não programadas e comprometendo a produtividade do processo e deslocando mão de obra para uma etapa de manutenção não prevista na cadeia do processo de soldagem. Este trabalho apresenta uma mesa de apoio com depósito cerâmico para o processamento e soldagem por atrito com pino não consumível. Para o desenvolvimento da mesa foram testados quatro depósitos cerâmicos, sob uma placa de aço, dos quais o de menor porosidade atingiu melhor desempenho. Essa mesa permitiu a realização de juntas soldadas com penetração completa de aços inoxidáveis duplex; resistir às altas cargas durante a soldagem de aços baixa liga alta resistência e realizar juntas dissimilares aço-alumínio, sem aderência do material mais macio à mesa suporte; bem como outras importantes características como confinar o calor e o metal plastificado, assim como determinar parâmetros de soldagem estáveis.

  12. Estudo de Procedimentos de Soldagem MIG/MAG para Aplicação de Revestimentos de Liga de Níquel Inconel 625 em Aço Estrutural ASTM A387 Gr.11

    Nathália Escóssio Cavalcante

    2016-03-01

    Full Text Available Resumo O presente trabalho objetiva o estudo de técnicas de soldagem aplicadas a reparo de componentes fabricados em aço ASTM A387 Gr.11, largamente utilizado em aplicações da indústria do petróleo e gás. Devido ao regime de trabalho e necessidade de utilização de materiais com boa resistência mecânica e à corrosão, utilizou-se como metal de adição a liga UNS N06625 (Inconel 625. O processo de soldagem utilizado foi o MIG/MAG e a técnica de soldagem aplicada foi a dupla camada. A metodologia do presente trabalho foi dividida em etapas, sendo a primeira a realização de ensaios exploratórios para definir a relevância dos fatores de controle estudados. A segunda etapa consistiu na aplicação do critério de dureza e de microestrutura para definir as melhores relações de energia para aplicação da técnica da dupla camada. A técnica da dupla camada se mostrou eficaz na melhora das propriedades da microestrutura da ZAC-GG dos revestimentos, verificou-se intenso refinamento de grão. Houve também redução nas medidas de dureza e microdureza. Para ambos os gases de proteção utilizados (Ar+25%He e Ar+4%CO2 foi possível obter relações de energia com afastamentos positivos. Em todas essas relações a energia da segunda camada foi maior que a energia da primeira camada.

  13. Desenvolvimento da ferrita delta na solda e ZTA resultante de soldagem plasma pulsada em um aço inoxidável supermartensítico Delta-ferrite development in weld and HAZ produced by pulsed plasma arc welding in a supermartensitic stainless steel

    Sérgio L. Henke

    2013-03-01

    Full Text Available A ferrita delta é considerada uma fase indesejável na microestrutura dos aços inoxidáveis martensíticos haja vista a mesma poder influenciar no desempenho da resistência à fadiga, tenacidade e corrosão sob-tensão. Sendo assim, o objetivo deste trabalho foi investigar o efeito da soldagem plasma pulsada sobre a distribuição e quantidade de ferrita delta em um aço inoxidável supermartensítico. Para tal foram obtidos cordões por meio de fusão superficial sobre uma amostra de aço inoxidável supermartensítico de alta liga utilizando corrente pulsada e convencional. Em seguida foi efetuada a caracterização microestrutural, em especial da ferrita delta, via análises metalográficas por meio de microscopia óptica e eletrônica de varredura . Os experimentos revelaram que, para o mesmo aporte térmico, a pulsação de corrente promoveu a formação de ferrita delta na forma de bandas ao longo do cordão de solda e redução significativa desta fase na ZTA quando comparada à soldagem convencional.The objective of this study was to investigate the effect of pulsed plasma welding on the distribution and amount of delta ferrite which is considered an undesirable phase in a supermartensitic stainless steel. For such weld beads have been obtained by melting the surface of a sample of a high-alloy supermartensitic stainless steel using pulsed and conventional current. Microstructural characterization, especially of delta ferrite, was performed by metallographic analysis by means of optical microscopy and scanning electron microscopy. The experiments showed that for the same heat input, pulsed current promoted the formation of delta ferrite in the form of bands along the weld bead and caused a significant reduction of this phase in HAZ as compared to conventional welding.

  14. Um critério para determinar a regulagem da tensão em soldagem MIG/MAG por curto-circuito A criterion to determine voltage setting in short-circuit GMAW

    Gabriel Maradei Carneiro de Rezende

    2011-06-01

    Full Text Available Este trabalho apresenta um estudo exploratório sobre um critério denominado "Critério Laprosolda para Estabilidade de Transferência em MIG/MAG com curto-circuito", o qual tem por finalidade uma análise quantitativa da regularidade da transferência metálica para regulagem de parâmetros para soldagem MIG/MAG por curto circuito convencional. Inicialmente é apresentado o embasamento para elaboração deste critério. A avaliação da confiabilidade do mesmo foi feita por meio de soldagens e comparações dos resultados com o rendimento de deposição e com as características geométricas do cordão de solda. Para isto, chapas de teste com 3,18 mm de espessura e abertura de raiz de 1 mm entre elas foram soldadas, dentro dos mesmos parâmetros de corrente e velocidade de alimentação, usando arame AWS ER70S-6 de 1,2 mm de diâmetro protegido pela mistura Argônio 85% - Dióxido de Carbono 15%. Para atender a relação proposta, varreu-se a regulagem de tensões de soldagem desde valores muito baixos até muito altos para o que se esperava para esta condição de soldagem. Os resultados confirmam a efetividade do "Índice de Regularidade" como meio de avaliar regulagens de soldagem MIG/MAG visando minimizar respingos e otimizar o acabamento do cordão.This paper presents an exploratory study on a criterion called "Criterion for Stability Laprosolda Transfer in MIG / MAG with short circuit", which aims at a quantitative analysis of the regularity of metal transfer for setting parameters for MIG / MAG conventional in short circuit. Initially it is stated the foundation for development of this criterion. The evaluation of that was made by welding and comparisons of results with the efficiency of deposition and the geometric characteristics of the weld bead. For this, the test plates with 3.18 mm thick and 1 mm gap between them was welded in the same range of current and feeding speed, using wire AWS ER70S-6 1.2 mm of diameter protected by the

  15. Validação de um Sistema Robotizado Recém Desenvolvido para a Soldagem pelo Processo Friction Stir Welding por meio da União e Caracterização de Juntas da Liga de Alumínio 5052 H34

    Bruno Silva Cota

    2017-12-01

    Full Text Available Resumo Este projeto trata da validação de um sistema recém desenvolvido para a soldagem pelo processo friction stir welding, que foi adaptado a um robô antropomórfico com capacidade de 500 kg e seis graus de liberdade. Para garantir que o sistema projetado é capaz de soldar materiais pelo processo FSW, ou seja, garantir que possui rigidez, resistência e torque suficientes para realizar a operação de soldagem, faz-se necessário realizar a validação do mesmo. Para tanto, foi necessário soldar um material conhecido, com parâmetros já estabelecidos, e utilizar uma ferramenta apropriadamente dimensionada. Dessa forma, escolheu-se a liga 5052 H43 de 3 mm de espessura, usada na produção de navios, embarcações e estruturas automotivas. Para a soldagem das juntas finais foi usada uma ferramenta fabricada em AISI H13, com pino cônico liso e diâmetro do ombro de 18 mm. A velocidade rotacional da ferramenta foi mantida constante em 378 rpm, e a velocidade de avanço em 7,5 mm/min, sendo a inclinação da ferramenta de 2°. Verificou-se após os ensaios que o sistema de soldagem projetado se mostrou eficaz em aplicações de soldagem FSW, apresentando torque e resistência mecânica suficientes para a união de materiais com baixo ponto de fusão. Por meio dos parâmetros utilizados, bem como da geometria da ferramenta, foi possível obter juntas da liga de alumínio 5052 H34 soldadas com: bom aspecto superficial, baixos valores de rebarba, ausência de sulcos ou vazios ao longo da linha de soldagem e com penetração total.

  16. Sistema embarcado para monitoramento sem fio de sinais em soldagem a arco elétrico com abordagem tecnológica Embedded system for wireless signal monitoring during arc welding with technological approach

    Marcus Vinícius Ribeiro Machado

    2012-06-01

    Full Text Available Industrialmente, o processo de soldagem a arco é o mais importante na produção e reparo de equipamentos, e sendo um processo especial de fabricação, que não pode ser completamente inspecionado contra imperfeições somente após sua finalização, o monitoramento da produção se faz necessário. Este monitoramento é tecnologicamente requerido pelas normas ISO 3834:2005 e ISO 17662:2005, que dizem que o fabricante deve adotar medidas para garantir a qualidade necessária, além de especificarem os dados que devem ser monitorados e a correta calibração dos sistemas e equipamentos de medida. Este, portanto, pode ser usado para garantir documentação do processo e tomadas de ações corretivas. Existem sistemas que realizam o monitoramento satisfatoriamente, mas o uso de comunicação por cabos e/ou com computador dedicado dificultam suas aplicações industriais. Então, um sistema embarcado, independente, que monitore diferentes sinais do processo de soldagem e que se comunique de forma robusta e flexível a diferentes equipamentos é fundamental para a indústria. Este sistema deve ser de utilização simplificada e apresentar o estado da arte em tecnologia de comunicação. Devido a essa necessidade, foi então projetado e construído um sistema para monitoramento sem fio de sinais em soldagem a arco elétrico, denominado de MoSo Wi-Fi. Três canais de aquisição estão disponíveis (tensão, corrente e velocidade de alimentação de arame, sendo validados pela instrumentação de soldagens TIG CA e MIG/MAG (curto-circuito, goticular e pulsado, demonstrando grande aplicabilidade e robustez a um baixo custo de hardware.Industrially, arc welding process is the most important in equipment production and repair, and being a special manufacturing process, which cannot be completely inspected for flaws only after its completion, production monitoring is necessary. This monitoring is technologically required by ISO 3834:2005 and ISO 17662

  17. Sistema de visão por infravermelho próximo para monitoramento de processos de soldagem a arco Near-infrared vision system for arc-welding monitoring

    Carolina Pimenta Mota

    2013-03-01

    Full Text Available A visão, o sentido predileto do ser humano, e sua grande capacidade de captar, processar e interpretar grandes quantidades de dados de natureza visual tem sido, ao longo dos anos, um grande estímulo para o desenvolvimento de técnicas e de dispositivos tecnológicos que a reproduzam num sistema computacional. Nos processos de soldagem, a visão pode fornecer dados na inspeção e qualidade da junta soldada, no monitoramento de parâmetros, na correção de trajetórias até, por fim, no estudo dos fenômenos envolvidos no processo. Porém, a radiação luminosa emitida pelo arco representa uma barreira para tais estudos baseados na visualização do processo. Uma das formas utilizadas atualmente para se obter a visualização do processo, sem a interferência do arco, consiste em iluminar o processo com o infravermelho próximo e utilizar filtros de interferência (passa-faixa, em torno deste mesmo comprimento de onda, durante a aquisição das imagens. Uma solução para a iluminação infravermelha, de aplicação crescente, envolve o uso de diodos laser de alta potência, com baixo custo e menor complexidade de instalação do que os lasers convencionais. Desta forma, a proposta deste trabalho foi a criação de um sistema de visão dos processos de soldagem a arco, de baixo custo e alta flexibilidade, indo desde a caracterização dos espectros de emissão luminosa do arco, passando pela criação de uma topologia de acionamento para o diodo de alta potência no infravermelho próximo, respeitando suas limitações de uso e maximizando a potência luminosa emitida, criação dos circuitos de controle, escolha dos equipamentos e componentes ópticos e, por fim, projeto e aplicação de um protótipo em processos de soldagem. As limitações do sistema de visão, como um todo, foram encontradas através de sua aplicação com soldagem TIG e MIG/MAG. Nestes ensaios, embora não tenha sido capaz de sobrepor a luz do arco, o sistema

  18. Estudo de Procedimentos de Soldagem MIG/MAG para Aplicação de Revestimentos de Liga de Níquel Inconel 625 em Aço Estrutural ASTM A387 Gr.11

    Cavalcante, Nathália Escóssio; Andrade, Tathiane Caminha; Pinheiro, Pedro Helton Magalhães; Miranda, Hélio Cordeiro de; Motta, Marcelo Ferreira; Aguiar, Willys Machado

    2016-01-01

    Resumo O presente trabalho objetiva o estudo de técnicas de soldagem aplicadas a reparo de componentes fabricados em aço ASTM A387 Gr.11, largamente utilizado em aplicações da indústria do petróleo e gás. Devido ao regime de trabalho e necessidade de utilização de materiais com boa resistência mecânica e à corrosão, utilizou-se como metal de adição a liga UNS N06625 (Inconel 625). O processo de soldagem utilizado foi o MIG/MAG e a técnica de soldagem aplicada foi a dupla camada. A metodologia...

  19. Efeito de dois sistemas de soldagem na alteração dimensional nas ligas de cobalto-cromo verificado por meio de análise por extensometria linear elétrica e resistência à flexão

    Castilho, Anderson Almeida [UNESP

    2009-01-01

    O objetivo neste estudo foi avaliar a alteração dimensional provocada pelos procedimentos de soldagem nas infra-estruturas de próteses fixas impanto-suportadas por meio de análise de extensometria linear elétrica assim como se determinar a resistência flexão de dois tipos de juntas soldadas (Arco-Plasma e Laser) em liga Odontológica Co-Cr. Para tanto, estruturas metálicas foram fundidas pelo método de indução para pilares tipo micro-unit. Para esse estudo, foram investigados três grupos: Grup...

  20. Revestimento de Níquel Depositado pela Soldagem MIG e MIG com Arame Frio

    Carlos Alberto Mendes da Mota

    Full Text Available Resumo: Este artigo apresenta um estudo das características operacionais, geométricas e microestruturais de soldas MIG e MIGAF (MIG com arame frio aplicadas no revestimento de chapa de um aço AISI 1020, com uma superliga de níquel ER NiCrMo-4, tipo Hastelloy 276C. A soldagem foi automatizada, na posição plana, e realizada por uma fonte eletrônica em CC+ com aquisição instantânea dos oscilogramas de corrente e tensão de soldagem. As variáveis de entrada foram às velocidades do arame eletrodo e do arame frio, e a velocidade de soldagem. Foram avaliadas a operacionalidade dos processos e o efeito da energia de soldagem sobre as características geométricas (reforço e largura, diluição, microestrutura e microdureza do revestimento. Os resultados indicaram um bom desempenho operacional, a ausência de defeitos nos passes isolados e nos revestimentos para as soldagens com MIGAF. Além disso, constataram-se menores níveis de diluição.

  1. Uma breve revisão histórica do desenvolvimento da soldagem dos aços API para tubulações A brief history review of development on API steels welding for pipeline

    Jaime Casanova Soeiro Junior

    2013-06-01

    Full Text Available Este trabalho enfoca o desenvolvimento dos aços API para tubulações desde o aço API 5L X42, desenvolvido em 1948, através de laminação a quente seguida de tratamento térmico. Desde então foram feitos diferentes desenvolvimentos visando aumentar a resistência mecânica e a tenacidade, além de melhorar a soldabilidade. Entre eles, a adição de elementos de liga, produzindo os aços ARBL e a utilização de rotas de processamento termomecânico durante a laminação. Inicialmente a rota utilizada era a laminação a quente controlada (TMCR, com utilização de elemento microligante como Nb para os aços X60 e o conjunto Nb e V para os aços X65 e X70, associado a uma redução do teor de carbono. Posteriormente foi implantada a rota de fabricação do aço por laminação controlada seguida de resfriamento controlado (TMCP, com redução de carbono e adição de Nb e Ti para os aços X80, e adições de Mo, Nb, Be Ti para os X100. A redução do carbono foi motivada também para melhorar a sua soldabilidade e, por este motivo, estes aços são soldados por diferentes processos de soldagem, como o eletrodo revestido. Desenvolvimentos recentes com raiz feita com MAG-TC e enchimento com arame tubular tem dado resultados animadores.This paper is a brief history on the development of pipelines steels since the API 5L X42 steel, developed in 1948 by hot rolling followed by heat treatment. Subsequently different developments were made to increase the strength and toughness of these materials, and to improve their weldability. Among them, the addition of microalloying elements, producing HSLA steels and thermomechanical processing routes during hot rolling. Initially the route used was the controlled hot rolling (TMCR, together with microalloying element such as Nb for X60 steel and Nb plus V for X65 and X70 steels, associated with a reduction in carbon content. Later, the thermomechanical controlled process (TMCP manufacturing route was

  2. Manufatura Aditiva: o papel da soldagem nesta janela de oportunidade

    Eduardo André Alberti

    2014-06-01

    Full Text Available A manufatura aditiva (MA é uma evolução da prototipagem rápida no sentido que cria um produto físico a partir de um arquivo digital (CAD 3D, entretanto sua utilização extrapola a produção de protótipos. Esta técnica envolve o projeto de um componente em camadas, estas multicamadas são depositadas por processos de soldagem produzindo o componente sem a necessidade de moldes ou outras ferramentas. Inicialmente esta tecnologia quase se restringia a processos de alta densidade de energia entretanto a busca por maior competitividade levou utilização de processos de soldagem a arco, utilizando material de adição na forma de arame ou de pó. Este trabalho tem por objetivo revisar as informações mais recentes com particular destaque para a MA utilizando processos a arco. São destacados os desafios envolvidos na fabricação de componentes por MA tanto na deposição das multicamadas como na fase de acabamento.

  3. Influência da Posição e dos Parâmetros de Soldagem na Soldagem TIG Orbital Aplicada a Tubulações de Aço Baixo Carbono

    Daniel Wallerstein Figueirôa

    2015-12-01

    Full Text Available Resumo A característica mais marcante da soldagem TIG Orbital é a constante alteração na posição de soldagem enquanto a tocha acompanha o perfil geométrico dos tubos. No contexto da soldagem TIG orbital de tubos de grande diâmetro e paredes espessas, é investigada a relação entre a posição de soldagem, uso de corrente constante ou pulsada e ainda valor da corrente média nas características geométricas dos cordões obtidos. Foram realizadas soldas de deposição em tubos de aço carbono SAE 1020, bem como macrografias das seções transversais dos cordões via microscopia óptica. Filmagens em alta definição contribuíram para a compreensão do comportamento da poça de fusão nas diferentes posições de soldagem. As características geométricas foram quantificadas através das macrografias com o uso de um software e foi traçada a relação destas com as variáveis citadas. Além disso, foi feita uma análise microestrutural das amostras, correlacionando com a microdureza Vickers. Concluiu-se que cordões soldados com corrente pulsada apresentam maiores reforço e largura, bem como maior dureza e microestrutura mais refinada. A posição vertical ascendente resulta em cordões com menor fator de forma e maior penetração, e a posição sobre cabeça resulta em cordões de baixo fator de forma.

  4. Seleção dos parâmetros através dos custos de soldagem para aplicação de revestimento com ligas de níquel depositadas pelo processo MIG/MAG Using the welding costs to select welding parameters for Weld Overlay with nickel alloy through the GMAW process

    Antonio Rodolfo Paulino Pessoa

    2011-03-01

    Full Text Available Neste trabalho foram calculados e comparados os custos de soldagem associados a cada um dos ensaios realizados, como forma de determinar parâmetros operacionais adequados e economicamente viáveis para soldagem com o processo MIG/MAG com transferência metálica por curto-circuito, visando uma correta deposição de revestimentos com ligas de níquel sobre um substrato de aço C-Mn. O número de ensaios a serem realizados, foi determinado pelo uso do método Taguchi que dividiu os ensaios em duas matrizes L9, resultando num total de 18 ensaios. Na comparação dos gastos despendidos em cada um dos ensaios foi utilizado o custo direto total da soldagem de um revestimento com 55 mm de largura e 190 mm de comprimento, utilizando uma sobreposição de 50%. Com base nos resultados dos ensaios foram pré-selecionados quatro ensaios (R7, R11, R12 e RC4, dentre os quais o ensaio R11 apresentou o menor custo. Mas vale ressaltar que nos quatro ensaios pré-selecionados o material de adição utilizado foi a liga 625, pois esta liga apresentar um custo do arame-eletrodo muito inferior as demais ligas (C-276 e 686. Assim a escolha do material de adição para aplicação do revestimento ficou restrita somente a liga 625.In this work were calculated and compared the welding costs for each of the tests performed to determine operational parameters and economically feasible for welding with GMAW process in a short circuiting transfer mode, aiming at a correct weld overlay with nickel alloy on a substrate of C-Mn steel. The number of tests to be performed was determined by using the Taguchi method that divided the tests into two L9 orthogonal arrays resulting in a total of 18 experiments. To compare the costs incurred in each of the tests we used the total direct cost of welding a layer with dimensions of 55 x 190 mm, using an overlap of 50%. Based on the results of the tests were pre-selected four tests (R7, R11, R12 and RC4, among which the test R11 has the

  5. Seleção de parâmetros através do método Taguchi para soldagem de revestimento com ligas de níquel pelo processo MIG/MAG Using the Taguchi method to select welding parameters for weld overlay with nickel alloy through the GMAW process

    Antonio Rodolfo Paulino Pessoa

    2010-12-01

    Full Text Available Neste trabalho utilizou-se o método Taguchi (planejamento Robusto de experimentos, para cumprir com um reduzido número de ensaios, dois objetivos: obter a influência dos fatores de controle sobre as variáveis respostas e determinar as condições ideais para aplicação das ligas de níquel nas soldagens de revestimentos através do processo MIG/MAG com transferência metálica por curto-circuito. Foram escolhidos seis fatores de controle com três níveis cada: Tensão de referência, Velocidade de soldagem, Tipo de tecimento, Técnica da tocha, Gás de proteção e o Material de adição. Por sua vez as variáveis respostas escolhidas foram: Diluição (D e Razão entre o reforço e a largura (R/L. As soldagens foram realizadas na posição plana por simples deposição sobre chapas de aço ASTM 516 Gr60 com dimensões de 200 x 50 x 12,7 mm. O uso do tecimento proporcionou cordões com baixos valores da razão R/L e obteve valores bastante baixos de diluição chegando à ordem de 5%. A combinação dos níveis dos fatores de controle apontados como ótimos pelo método Taguchi resultaram em valores para as variáveis repostas consideradas adequadas para a soldagem de revestimento.In this work aim the Taguchi method (Robust design of experiments was chosen to achieve with a limited number of tests two objectives: the first was to the influence of the control factors (welding parameters on quality characteristics (weld bead geometry and the second was to determine optimal conditions for weld overlay with nickel alloy through the GMAW process in a short circuiting transfer mode. Six control factors were employed with three levels each: Reference voltage, Welding speed, Arc oscillation, welding gun orientation (Perpendicular, forehand and backhand, Shielding gas and filler metal. Already the employed quality characteristics were: Percent dilution (D and the ration between reinforcement and bead width (R/L. The weldings were accomplished using

  6. Transferência de calor aplicada à prototipagem rápida por deposição de metal em camadas sucessivas utilizando soldagem 3D

    Felipe Ferreira Fraga

    2013-12-01

    Full Text Available Este trabalho apresenta um estudo dos fenômenos de transferência de calor no processo de prototipagem rápida por deposição de metal em camadas sucessivas utilizando soldagem a arco, também chamada de soldagem 3D (3D Welding. O objetivo é desenvolver um modelo simplificado e compreender o processo de transferência de calor e suas relações com os parâmetros de soldagem, de modo a se possibilitar um controle dos ciclos térmicos a que estará sujeito o material depositado. Desenvolveu-se um modelo físico-matemático para a transferência de calor durante o processo de soldagem, o qual é resolvido numericamente pelo método das diferenças finitas, permitindo a simulação de situações típicas desse tipo de processo de fabricação. O modelo numérico desenvolvido foi validado por meio da simulação de casos específicos para os quais se conhecem soluções analíticas. A partir das equações do modelo, definiram-se parâmetros adimensionais, dentre os quais pode-se citar o grupo adimensional π1, relacionado principalmente à velocidade de soldagem. Realizaram-se alguns experimentos numéricos observando a influência desse grupo nas temperaturas máximas, médias e nas amplitudes dos ciclos térmicos que a peça está sujeita.

  7. Efeitos da Energia de Soldagem e Consumível sobre a Resistência à Flexão Simples de Juntas Soldadas em Perfis Tubulares de Aço TMCP

    Rafael Luciano Dalcin

    2016-03-01

    Full Text Available Resumo A introdução dos aços fabricados por processamento termomecânico controlado (TMCP demandou maiores propriedades mecânicas e metalúrgicas das juntas soldadas sobre eles produzidas. Em função desses fatores, a energia de soldagem é estritamente limitada, e para evitar uma eventual redução da resistência mecânica da zona afetada pelo calor (ZAC, é necessário testar os procedimentos de soldagem próximos daqueles que serão usados na estrutura real. Desta forma, o objetivo deste estudo é obter dados detalhados referentes à eficiência mecânica de juntas soldadas pelo processo MAG e com diferentes energias de soldagem, sobre perfis tubulares quadrados em aço TMCP, formando um conjunto soldado coluna/viga. Portanto, seis distintas energias de soldagem e dois metais de adição foram utilizados (AWS ER80S-G e AWS ER120S-G, com as soldas posicionadas em todo o contorno do perfil. As doze estruturas soldadas foram instrumentadas e submetidas à flexão simples. Comparando-se as juntas soldadas produzidas com mesma energia de soldagem, e apesar dos efeitos similares sobre a zona afetada pelo calor (ZAC, aquelas fabricadas com o consumível AWS ER120S-G apresentaram maior resistência mecânica.

  8. Avaliação metalúrgica da soldagem de revestimento inox austenítico sobre aço SAE 4130

    Márcio de Souza Elias

    2014-12-01

    Full Text Available O objetivo deste trabalho foi realizar uma avaliação metalúrgica da soldagem de revestimento inox austenítico sobre a área de selagem de tubos de Riser fabricados em aço SAE 4130. O estudo foi dividido em duas etapas. A primeira etapa teve como objetivo a determinação da taxa de diluição e taxa de deposição para os níveis máximo e mínimo de energia de soldagem conforme procedimentos de soldagem (EPS com os processos TIG e ER. A seguir, foi feita análise e estudo com o diagrama de Schaeffler para identificar os consumíveis de solda mais adequados, conforme critérios de qualidade estabelecidos. Este estudo identificou o metal de adição 312 para a primeira camada, o 309 e 308 para a segunda. Todos usando o nível máximo de energia de soldagem e o processo de soldagem ER, com benefícios à produtividade. A segunda etapa teve como objetivo a validação dos resultados empíricos encontrados na 1ª etapa, com a execução de soldas de revestimento com duas camadas cada, e a caracterização metalúrgica das juntas soldadas por ensaios mecânicos e análise microestrutural por MO e MEV. Os resultados dos ensaios mecânicos e da microestrutura foram considerados satisfatórios, atendendo os critérios de qualidade adotados. Foi observada uma microestrutura austeno-ferritica com teor de ferrita delta entre 10 a 15 % nas duas camadas do revestimento. O eletrodo 312 assumiu posição de destaque na aplicação da 1ª camada da solda de revestimento sobre o aço SAE 4130, em função do seu maior teor de ferrita delta e cromo, evitando a formação de trincas a quente. Para a segunda camada, tanto o 309 como o 308 podem ser usados. Todas as soldas foram feitas com elevada energia de soldagem, garantindo o aumento da produtividade, sem alteração significativa nas características físicas e mecânicas.

  9. Caracterização mecânica e estudo do perfil térmico na soldagem por fricção rotativa de materiais dissimilares

    Eder Paduan Alves

    2016-01-01

    Na busca de processos alternativos utilizados para união de materiais dissimilares, destaca-se o processo de soldagem por fricção rotativa (Rotary Friction Welding), utilizado em tecnologia de ponta na indústria aeroespacial, aeronáutica, nuclear, bélica e automotiva. O processo de soldagem por fricção rotativa (SFR) acontece no estado sólido sem ocorrência de fusão entre as partes, e apresenta como principais mecanismos a difusão e mistura mecânica. Este trabalho tem como objetivo a caracter...

  10. Soldagem TIG de elevada produtividade: influência dos gases de proteção na velocidade limite para formação de defeitos High productivity TIG welding: influence of shielding gases on the limit speed for defect formation

    Mateus Barancelli Schwedersky

    2011-12-01

    Full Text Available O processo TIG, em configurações tradicionais, apresenta problemas quando utilizado de maneira autógena com elevadas corrente e velocidade de soldagem. Nessa condição, normalmente ocorrem defeitos no cordão, principalmente descontinuidades denominadas humping. Em estudo realizado no LABSOLDA, foram obtidas soldas de excelente qualidade com o processo TIG atingindo velocidades de 1,5 m/min. Este procedimento, utilizando na proteção misturas argônio-hidrogênio, possibilitou velocidade semelhante ao processo MIG/MAG convencional, com a vantagem de ser realizada sem material de adição. O presente trabalho tem o objetivo de fornecer subsídios para uma nova análise da formação dos defeitos na soldagem TIG de elevada produtividade, já que a teoria baseada na pressão do arco não contempla totalmente o que tem sido observado na prática. Foram realizados ensaios com diferentes correntes utilizando argônio, hélio e misturas argônio-hidrogênio no gás de proteção. Os resultados mostram que para a mesma corrente média, à medida que o teor de H2 foi aumentado, ocorreram também gradativos aumentos da área fundida e eficiência de fusão. Foi possível mostrar indícios de que o mecanismo de formação de defeitos não depende somente da pressão do arco, mas sim do balanço entre pressão do arco e quantidade de metal fundido, que é dependente da eficiência de fusão proporcionada pelo gás utilizado.Under usual configurations, the TIG process presents problems when used autogenously with high current and welding speed. In this condition defects in the weld bead usually occur, especially discontinuities called humping. In a study conducted at LABSOLDA, welds with excellent quality were obtained using the TIG process reaching speeds of 1.5 m/min. Under argon-hydrogen shielding gas mixtures welding speed similar to the conventional MIG/MAG process was allowed, with the advantage of being performed without filler material. The

  11. Improving productivity and quality in plastic and thin metallic plates manufacturing by using ultrasonic welding processes Melhorando a produtividade e qualidade na fabricação em plástica e chapas finas de metal por soldagem por ultra-som

    D. Dehelean

    2009-12-01

    Full Text Available The paper presents an overview of the research done at the Romanian National R&D Institute for Welding and Material Testing ISIM Timisoara in the field of ultrasonic process development. It starts with a general presentation of the value added by the welding sector in Europe. There are presented figures representing the size of the welding sector in Romania. The need of development of new high efficiency welding processes is mentioned, ultrasonic welding being one of the special welding processes with exceptional application perspectives. Practical examples of industrial application of the ultrasonic welding process for joining plastic and metallic materials are presented. A special case study refers to the welding of new shape memory alloys. The use of the ultrasonic welding instead of an conventional welding process has lead in each presented case study to an increase of the efficiency of the welding process through higher productivity and saving of manpower, consumable, energy.Este trabalho apresenta um panorama dos trabalhos de pesquisa conduzidos no Instituto nacional Romeno de P&D em Soldagem e Avaliação de Materiais (ISIM - Timisoara no desenvolvimento de processos ultrassônicos. Ele se inicia com uma apresentação geral pelo valor adicionado pelo setor de soldagem à Europa. São apresentados valores representativos do tamanho do setor de soldagem na Romênia. A necessidade do desenvolvimento de novos processos de soldagem de alta eficiência é mencionada, sendo a soldagem ultrassônica um dos processos especiais de soldagem com perspectivas excepcionais de aplicação. Exemplos práticos da aplicação industrial deste processo de soldagem para a união de plásticos e de metais são apresentados e um caso especial se refere à soldagem de novas ligas com efeito de memória de forma. O uso de soldagem por ultrassom no lugar de um processo convencional de soldagem resultou, em cada um dos estudos de caso apresentados, em um aumento

  12. Influência da incorporação de resíduo de escória de fluxo de soldagem nas propriedades tecnológicas de argamassa de múltiplo uso e cerâmica vermelha para construção civil Influence of the incorporation of waste of slag of welding flux on the technological properties of multiple use mortar and red ceramic for civil construction

    C. E Viana

    2010-03-01

    Full Text Available O processo de soldagem a arco submerso é empregado em grande escala na indústria metal-mecânica. No entanto, este processo gera enorme quantidade de resíduo de escória. Em geral, este resíduo vem sendo disposto em lixões. Nos últimos anos, a área de cerâmica tem atraído grande atenção para reciclagem de resíduos industriais. Neste trabalho foi feito um estudo objetivando avaliar a influência do resíduo de escória de fluxo de soldagem sobre as propriedades tecnológicas de argamassa de múltiplo uso e cerâmica vermelha para uso na construção civil. O resíduo de escória de fluxo de soldagem foi caracterizado em relação à composição química, difração de raios X, análise do tamanho de partículas e massa específica real. A argamassa foi preparada com a incorporação de resíduo de escória de soldagem em substituição total de areia natural (agregado miúdo tradicional. As argamassas foram caracterizadas em termos de consistência, densidade de massa no estado fresco, teor de ar incorporado e resistência à compressão. Análise microestrutural das argamassas foi feita via MEV. Foi preparada também uma série de misturas argila/resíduo contendo até 10% em peso de resíduo de escória de fluxo de soldagem. As peças cerâmicas foram preparadas por prensagem uniaxial e queimadas entre 850 ºC e 950 ºC. As peças queimadas foram caracterizadas quanto à retração linear, absorção de água, porosidade aparente, massa específica aparente e tensão de ruptura à flexão. Os resultados mostraram que o resíduo de escória de fluxo de soldagem pode substituir areia natural como agregado miúdo em argamassa de múltiplo uso. Além do mais, o resíduo de escória pode ser incorporado em cerâmica vermelha (tijolos e blocos cerâmicos como substituto parcial de argila natural.The submerged-arc welding process is widely used in the metal-mechanic industry. However, this process generates huge amounts of slag waste. In

  13. Deposição por plasma com arco transferido Hardfacing by plasma transfer arc process

    Víctor Vergara Díaz

    2010-03-01

    Full Text Available Em virtude do Processo de Soldagem Plasma com Alimentação de Pó ter similaridades com o Processo de Soldagem Plasma com Alimentação de Arame, foi realizado um estudo comparativo entre ambos os processos utilizando-se a liga a base de cobalto comercialmente conhecida como Stellite 6, como material de adição na forma de pó e arame. A pesquisa foi realizada com a expectativa de ser aplicada nas operações de revestimentos de superfícies, em especial em pás de turbinas hidráulicas desgastadas por cavitação. A seleção do material de adição a ser empregado depende da natureza do mecanismo de desgaste encontrado. No Labsolda, a liga Stellite 6 vem sendo uma das mais utilizadas, por apresentar uma excelente resistência ao desgaste erosivo por cavitação. Foi avaliada a influência da vazão de gás de plasma a partir dos valores de diluição, dimensões do cordão, dureza e microestrutura. O Processo de Soldagem Plasma com Alimentação de Pó foi o que produziu o melhor acabamento superficial, menor diluição, melhor molhamento e maior largura. Com isto abre-se uma nova perspectiva para revestimentos metálicos e neste contexto se insere a recuperação por soldagem de partes erodidas de turbinas hidráulicas.The Plasma powder transferred arc welding process, which uses feed stock in the powder form, has similarities with Plasma wire transferred arc welding. This work describes a comparative study of the two processes using a Cobalt-based alloy commercially known as Stellite 6. This Co-based alloy is recognized for its superior cavitation erosion resistance. The aim of this work is to investigate the potential of PTA coatings for the protection and refurbishiment hydraulic turbine blades. Coatings were evaluated for the influence of Plasma gas flow rate on coating dilution, geometry, hardness and microstructure. Coatings processed with the atomized Stellite 6 powder feestock showed a superior surface quality, lower dilution

  14. Soldagem por ponto no estado sólido de ligas leves Solid state spot welding of lightweight alloys

    Leonardo Contri Campanelli

    2011-09-01

    Full Text Available A recente preocupação quanto às mudanças climáticas vem impulsionando pesquisas em eficiência energética dos meios de transportes no sentido de reduzir a emissão de gases. Uma das principais soluções consiste na redução do peso estrutural através da aplicação de novos materiais, como as ligas leves de alumínio e magnésio. Entretanto, novos usos ficam muitas vezes limitados pela dificuldade de união desses materiais. A técnica de soldagem por fricção e mistura (FSW é um processo de união no estado sólido que surge como uma alternativa viável para substituir ou complementar as tecnologias de união consagradas. Como uma junta contínua não é sempre a requisitada, duas tecnologias de união por ponto derivadas do FSW estão em desenvolvimento: soldagem por fricção e mistura por ponto (FSSW e soldagem por fricção por ponto (FSpW. Além de fornecerem juntas de elevada resistência e praticamente isentas de defeitos, estas técnicas apresentam alta eficiência energética, curto ciclo de soldagem, facilidade de automação e compatibilidade com o meio-ambiente, fazendo frente às técnicas convencionais de união por ponto, como a soldagem por resistência por ponto (RSW e a rebitagem.The recent concern about climate change has stimulated research into transport energy efficiency in order to reduce the emission of gases. One of the main solutions is to reduce the structural weight through the application of new materials, such as aluminum and magnesium lightweight alloys. However, new applications are often limited by the difficulty of joining these materials. Friction Stir Welding (FSW is a solid state joining technique that emerges as a viable alternative to replace or complement the established joining technologies. As a continuous weld is not always requested, two spot welding technologies derived from FSW are under development: Friction Stir Spot Welding (FSSW and Friction Spot Welding (FSpW. Besides providing

  15. Estudo do comportamento do aço API 5L X80 quando submetido à soldagem por processo automatizado Study on the behavior of API 5L X80 steel when subjected to automated welding process

    Siderley Fernandes Albuquerque

    2012-06-01

    Full Text Available No Brasil, a soldagem de tubulações tem sido praticamente de forma manual, entretanto, a utilização de processos de soldagem automatizados têm crescido muito nos últimos anos, contribuindo para o maior controle dos parâmetros de soldagem, e conseqüentemente, a possibilidade de obtenção de juntas soldadas com melhores propriedades mecânicas. A soldagem de tubulações com aço API 5L X80 ainda vem sendo avaliada no Brasil no que diz respeito aos melhores procedimentos, parâmetros e processos de soldagem; a aplicação de processos automatizados nas condições específicas de campo constitui em uma opção ainda incipiente no país por se discutir ainda a relação custo/benefício com a sua implantação. Logo, o objetivo deste trabalho é avaliar o comportamento na ZTA de juntas soldadas do aço API 5L X80 utilizados para transporte de petróleo e gás quando submetidos à soldagem com diferentes parâmetros, procedimentos e processos de soldagem, incluindo o processo automatizado; os resultados indicam além da redução da extensão e do tamanho de grão da ZTA a preservação da estrutura bainítica do metal de base nesta região nas soldagem executadas com processos automatizados.The welding of pipes has been largely manual in Brazil, however, the use of automated welding processes have greatly increased in recent years, contributing to greater control of welding parameters, and consequently, the possibility of obtaining welded joints with better mechanical properties. The welding of pipes of API 5L X80 steel has been evaluated in Brazil considering to best practices, parameters and welding processes; the implementation of automated processes in the specific field conditions is relevant project and innovative design in this area. Therefore, the objective is to evaluate the behavior in the HAZ of the API 5L X80 steel used for transporting oil and gas when subjected to automated welding processes; the results indicated besides the

  16. Metodologia para parametrizar e avaliar a técnica da ''burn-zinc'' no processo de soldagem a ponto por resistência Methodology for parameterize and assessment of the burn-zinc technique in the resistance spot welding process

    Vinicius Castanheira do Nascimento

    2010-03-01

    Full Text Available Para minimizar os efeitos prejudiciais do zinco na soldagem a ponto por resistência de chapas galvanizadas, utiliza-se uma técnica tradicionalmente denominada ''Burn-Zinc'' (queima do zinco. Porém, existem poucas informações e estudos disponíveis na literatura sobre quando e como utilizá-la. O presente estudo teve a finalidade de avaliar a técnica de ''burn-zinc'', procurando entender melhor o fenômeno. Para tal, foi criada uma metodologia para determinação dos parâmetros ideais para cada combinação de chapa. Uma avaliação desta metodologia foi feita com uma série de soldagens com variações sistemáticas da corrente e pressão em níveis compatíveis para se obter a queima do Zn. Visualização das soldagens através de filmagem em alta velocidade, com sincronização dos sinais elétricos, foi empregada para entender os resultados. Uma vez definidos os parâmetros, soldagens foram realizadas com ou sem a aplicação da técnica. Os procedimentos experimentais propostos mostraram ser eficientes para a verificação e parametrização da técnica ''burn-zinc''. Mas houve evidências que a utilização da técnica nem sempre vai ocasionar redução no tempo total de operação.For minimizing the detrimental effects of zinc during resistance spot welding of galvanized sheets, a technique denominated Burn-Zinc is usually employed. However, there is no much information and studies available in the current literature about when and how to use this technique. The present work had the objective of assessing and understanding better this technique. For that, a methodology for determination of ideal burn-zing parameters as a function of the sheets was proposed. The evaluation of this methodology was carried out by a series of weldments, by systematically varying current and pressure at compatible levels for zinc burning. High speed filming, synchronized with the electrical signals, was employing for visualizing and results analyses

  17. Aplicação do processo laser CO2 de soldagem em aço ARBL na fabricação de rotores para máquinas elétricas

    Conz, Roberto [UNESP

    2004-01-01

    O objetivo deste trabalho foi substituir um bloco de grandes dimensões em aço forjado, por chapas finas de aço, laminadas a quente, soldadas pelo processo LASER CO2, destinadas à fabricação de rotores para máquinas elétricas com até 40 MW de potência, para tanto foram utilizadas chapas com 3 mm de espessura, empilhadas, compactadas e fixadas por tirantes. Considerando que a largura das bobinas e blanks disponíveis no mercado nacional não atendem às necessidades dimensionais do produto fez-se ...

  18. Influência da temperatura interpasse nas propriedades do aço inoxidável duplex durante a soldagem pelo processo a arco submerso

    Tatiana Resende Alvarez

    2014-06-01

    Full Text Available Os aços inoxidáveis duplex (AID são materiais que apresentam elevada resistência à corrosão com altos valores de resistência mecânica motivando sua utilização em diversos componentes de processo na indústria offshore. No entanto, existem grandes desafios na soldagem destes materiais em termos de produtividade e qualidade da junta produzida, tendo em vista sua ampla utilização desde componentes de pequenas espessuras, tais como umbilicais, até de grandes espessuras, como tubulações de linhas de injeção de água salgada. No que concerne a tubulações de espessuras pequenas é empregado satisfatoriamente o processo de soldagem Gas Tungsten Arc Welding (GTAW conhecido como TIG. No que diz a respeito a tubulações de paredes espessas foi implementado, recentemente, o processo automático de soldagem por arco submerso (SAW na linha de pré-montagem de tubulações, aumentando consideravelmente a produtividade das juntas produzidas. No entanto, existe uma grande demanda de tempo para a realização de um novo passe de solda, em virtude da máxima temperatura interpasse exigida ser inferior a 150ºC. Portanto, o presente trabalho apresenta os resultados da caracterização e avaliação da resistência à corrosão de uma junta soldada correspondente a uma tubulação de aço inoxidável duplex (AID UNS S31803 de 21,4 mm de espessura de parede soldada pelos processos de soldagem MIG (GMAW na raiz e arco submerso (SAW no enchimento e acabamento, empregando-se temperaturas interpasses entre 150 e 290ºC. Os resultados da caracterização das propriedades mecânicas, composição química e resistência à corrosão em diversas regiões da junta soldada foram comparadas com os obtidos para o metal de base (MB da tubulação, assim como com os valores mínimos exigidos pelas normas de projeto. Deste modo, o presente trabalho permite avaliar a influência da temperatura interpasse nas propriedades da junta em decorrência de um poss

  19. Análise metalográfica do titânio puro submetido à soldagem laser Nd: YAG e TIG

    Ana Cláudia Gabrielli Piveta

    Full Text Available INTRODUÇÃO: Os métodos de soldagem mais utilizados em Odontologia não podem ser aplicados ao titânio puro e às suas ligas em função da alta reatividade do titânio com elementos atmosféricos; dessa forma, o mesmo não deve ser soldado por processo comum. OBJETIVO: O objetivo deste trabalho foi avaliar a característica metalúrgica do titânio comercialmente puro sem solda e submetido aos processos de soldagem a laser e TIG. MATERIAL E MÉTODO: Foram confeccionados 15 corpos de prova em titânio comercialmente puro, cinco para cada condição, na forma de hastes cilíndricas, obtidas por fundição odontológica, sob atmosfera de gás argônio e vácuo, com calor produzido por um arco voltaico, com a injeção do titânio sob vácuo-pressão. Três grupos foram formados I: soldagem a laser; II: soldagem TIG, e III: sem solda. Os corpos de prova do grupo I e II foram seccionados ao meio e soldados por TIG e por laser, respectivamente; o grupo III foi mantido sem corte e sem solda, como controle. A análise metalográfica foi realizada sob aumentos de 50×, 100× e 200×, em microscópio. RESULTADO: Pelos resultados obtidos nas micrografias, o titânio comercialmente puro apresentou uma morfologia de grãos equiaxiais da fase α, o cordão de solda a laser apresentou estrutura martensítica e, na TIG, microestrutura Widmanstätten. CONCLUSÃO: A microestrutura martensítica é condizente com a alta taxa de resfriamento proveniente do processo de soldagem a laser. As estruturas martensítica e Widmansttäten são mais refinadas quando comparadas à microestrutura do metal base.

  20. Avaliação das Tensões Residuais em Juntas Soldadas de Inconel 625 Obtidas Através da Soldagem por Fricção e Mistura Mecânica

    Guilherme Vieira Braga Lemos

    Full Text Available Resumo A utilização de materiais nobres é requisito básico em aplicações onde existe um ambiente agressivo como na indústria do petróleo e nuclear. Neste panorama, a liga Inconel 625 é frequentemente utilizada como material de cladeamento no revestimento interno de dutos rígidos. Assim, as superligas de níquel exercem papel fundamental nos campos de exploração de águas profundas e, por isso, o conhecimento de métodos modernos de soldagem aplicados a estas ligas e suas consequências nos estados de tensões residuais é importante. Portanto, o presente trabalho faz uma avaliação das tensões residuais após a Soldagem por Fricção e Mistura Mecânica (SFMM em chapas soldadas de Inconel 625. A união das chapas foi realizada com rotação da ferramenta 200 e 1200 rpm e velocidade de soldagem constante (1mm/s. As medições de tensões residuais na superfície das juntas soldadas foram investigadas através da técnica de difração de raios-X. Além disso, foram avaliadas as macroestruturas e o aporte térmico de acordo com os parâmetros de soldagem empregados. Embora não existam muitos trabalhos relacionados ao processo SFMM para ligas de Inconel, provavelmente devido à sua dificuldade de soldagem, tem sido percebido um aumento na aplicação da soldagem no estado sólido como excelente alternativa para as superligas à base de níquel. Os resultados mostraram que diferentes parâmetros de processo produziram juntas soldadas distintas e, consequentemente, variações na distribuição de tensões residuais. Por fim, um aumento na velocidade de rotação da ferramenta ocasionou um aumento nas tensões residuais na zona de mistura.

  1. Análise de Distorções na Soldagem de Juntas em “X” e “V” em Modelos Reduzidos em Escala de Anéis Segmentados Utilizando o Monitoramento Contínuo com Sensores a Laser

    Jonathas Henrique Pereira

    2016-03-01

    Full Text Available Resumo Distorções em componentes soldados são alterações permanente de forma e dimensões resultantes das deformações plásticas que ocorrem devido as tensões térmicas desenvolvidas durante o processo de soldagem. Em função dos elevados custos para corrigir essas distorções de soldagem, existe grande interesse das indústrias em prever, monitorar e controlar estas distorções. Este trabalho compara as distorções ocorridas durante a soldagem de modelos de anel segmentado em escala reduzida com dois tipos de juntas (“X” e “V” utilizando a metodologia de monitoramento contínuo da evolução das distorções de soldagem com sensores a laser. Para o monitoramento contínuo são utilizados sensores a laser que são apoiados sobre a peça e os feixes foram projetados em um anteparo translúcido colocado em frente ao mesmo. Com a progressão da distorção durante a soldagem os feixes luminosos se movimentam pelo anteparo proporcionalmente a deformações ocorridas na peça. Os deslocamentos dos pontos luminosos refletidos no anteparo são filmados pelo lado oposto do anteparo. A discretização da filmagem permite analisar as deformações ao longo do processo soldagem e determinar a evolução das distorções em função do tempo. Foi confirmado que as soldagens realizadas em juntas em “X” apresentam menores valores de distorções que as juntas em “V”. Os resultados demostram que para os corpos de prova utilizados neste experimento pelo menos 60% da distorção ocorreu após a extinção do arco. Pelos testes experimentais foi possível afirmar que a técnica de monitoramento com sensores a laser é viável para utilizar na indústria e laboratórios de soldagem, porém faz-se necessário otimizar o processamento dos dados obtidos pela filmagem, permitindo um monitoramento instantâneo. A informação sobre a evolução das distorções durante a soldagem será útil para definir e monitorar de forma mais eficiente o

  2. Efeito do tipo de revestimento na soldagem a ponto de aços galvanizados Effect of coating type on spot welding of galvanized steel

    Tarcélio Anício da Silva

    2010-09-01

    Full Text Available Os aços galvanizados são cada vez mais utilizados pela indústria automobilística devido à sua excelente resistência à corrosão e boa trabalhabilidade. A soldagem a pontos por resistência de aços galvanizados apresenta o inconveniente de um maior desgaste dos eletrodos quando comparada com a soldagem de aços não revestidos. Este é causado pela reação do zinco com o cobre do eletrodo, formando uma liga Zn-Cu (latão que diminui a vida útil do eletrodo. No presente trabalho, foram feitos testes de soldagem a ponto utilizando aços livres de intersticiais (IF, revestidos por imersão a quente com zinco puro (GI e liga Zn-Fe (GA. Foram determinados os campos de soldabilidade dinâmicos e a vida útil dos eletrodos para juntas formadas pelas combinações GA/GA, GI/GI e GA/GI. O estudo do campo de soldabilidade dinâmica mostrou que os valores de corrente necessários para a obtenção de uma solda adequada aumentam mais rapidamente para a junta de materiais GI/GI e este efeito foi associado com a maior contaminação do eletrodo pelo Zn do revestimento. Por sua vez, a soldagem da junta GA/GI apresenta taxas de variação desta corrente um pouco maiores do que a da junta GA/GA, mas menores que a da junta GI/GI. Em geral, a junta GA/GI apresentou resultados nos testes de soldagem mais próximos dos da junta GA/GA em comparação com os testes com a junta GI/GI. Isto mostra a influência positiva, do revestimento GA, no aumento do número de pontos de solda, mesmo quando a junta é constituída de aços com dois tipos de revestimentos diferentes (GA e GI.Steels coated with zinc and zinc-iron alloys are being increasingly used by the car industry due to their excellent corrosion resistance and good workability. Spot welding of coated steels has the disadvantage of increasing electrodes wear when compared to uncoated steels. Such wear is caused by the reaction of the zinc coating with the copper of the electrode forming an alloy Zn

  3. Efeito da profundidade de soldagem no hidrogênio difusível de soldas molhadas Effect of water depth on diffusible hydrogen on wet welds

    Weslley Carlos Dias da Silva

    2012-12-01

    Full Text Available Em soldagem subaquática molhada, a ocorrência de poros e trincas a frio pode ter um efeito bastante prejudicial nas propriedades mecânicas da junta soldada. O hidrogênio contribui diretamente para o aparecimento destas duas descontinuidades. A quantidade de hidrogênio difusível (Hdif no metal de solda pode ser influenciada por diversos fatores. Todavia, pouco se sabe sobre a influência da profundidade de soldagem (pressão sobre a quantidade de Hdif no metal de solda. Neste trabalho, diversas medições de hidrogênio difusível foram feitas nas profundidades de 0,30 m, 10 m e 20 m e 30 m em soldagem molhada. O consumível utilizado foi o eletrodo comercial E6013 envernizado. As medições de hidrogênio difusível foram feitas através do método da cromatografia. Para medição de porosidade foi utilizado o método macrográfico e um programa analisador de imagem. O hidrogênio residual também foi medido. Os resultados mostraram que o hidrogênio difusível reduziu significativamente com o aumento da pressão hidrostática ao contrário da porosidade, que aumentou com o aumento da pressão hidrostática. Não se observou alterações apreciáveis no hidrogênio residual do metal de solda. Desta forma, é possível concluir que a profundidade de soldagem afeta diversos aspectos da soldagem subaquática molhada, em especial, o hidrogênio difusível e porosidade, conforme foi observado neste trabalho.In underwater wet welding, cold cracking and pores might have a deleterious effect in the mechanical properties of welded joint. The hydrogen might act in the occurrence of theses discontinuities. The amount of diffusible hydrogen in the weld metal can be influenced by several factors. However, not yet known whether the depth of welding (pressure affects the amount of diffusible hydrogen in weld metal. In this work, several measurements of diffusible hydrogen were made at following depth: 0.30 m, 10 m, 20 m and 30 m atwet welding. The

  4. Some pitfalls in welding of duplex stainless steels Algumas armadilhas na soldagem de aços inoxidáveis duplex

    Demian J. Kotecki

    2010-12-01

    encontradas com uma frequência relativamente alta para justificar um exame mais detalhado destas. A especificação inadequada do metal base frequentemente resulta em propriedades inadequadas da zona termicamente afetada (ZTA. Zona fundida autógena é também motivo de preocupação em função de limites no teor de nitrogênio. A situação mais comumente encontrada é o uso de UNS S31803 para o AID 2205 no lugar de S32205. O uso de um aporte térmico inapropriado ocorre mais frequentemente com AISD. Embora uma faixa de 0,5 a 1,5 kJ/mm seja uma recomendação normal de aporte térmico para AISD, tanto o passe de raiz como muitos pequenos cordões depositados no limite inferior desse intervalo de aporte térmico tendem a resultar em precipitação e/ou formação de austenita secundária no metal de solda submetido a ciclos térmicos repetidos. Tratamento térmico após soldagem (TTAT inapropriado ocorre quando metais de adição de maior teor de níquel (tipicamente 9% são usados. Estes tratamentos não são normalmente aplicados a AID, mas a conformação severa de cabeças, por exemplo, ou a soldagem para reparo de fundidos, pode requerer um recozimento após a soldagem. Especificações como a ASTM A790 e a A890 indicam um mínimo de 1040ºC para o recozimento e o fabricante tende a usar uma temperatura próxima deste mínimo. Contudo, o metal de adição de maior teor de níquel requer temperaturas mais elevadas para dissolver a fase sigma durante o aquecimento para a temperatura de recozimento.

  5. Estimativa da produtividade em soldagem pelo Método de Monte Carlo Productivity estimation in welding by Monte Carlo Method

    José Luiz Ferreira Martins

    2011-09-01

    Full Text Available O objetivo deste artigo é o de analisar a viabilidade da utilização do método de Monte Carlo para estimar a produtividade na soldagem de tubulações industriais de aço carbono com base em amostras pequenas. O estudo foi realizado através de uma análise de uma amostra de referência contendo dados de produtividade de 160 juntas soldadas pelo processo Eletrodo Revestido na REDUC (refinaria de Duque de Caxias, utilizando o software ControlTub 5.3. A partir desses dados foram retiradas de forma aleatória, amostras com, respectivamente, 10, 15 e 20 elementos e executadas simulações pelo método de Monte Carlo. Comparando-se os resultados da amostra com 160 elementos e os dados gerados por simulação se observa que bons resultados podem ser obtidos usando o método de Monte Carlo para estimativa da produtividade da soldagem. Por outro lado, na indústria da construção brasileira o valor da média de produtividade é normalmente usado como um indicador de produtividade e é baseado em dados históricos de outros projetos coletados e avaliados somente após a conclusão do projeto, o que é uma limitação. Este artigo apresenta uma ferramenta para avaliação da execução em tempo real, permitindo ajustes nas estimativas e monitoramento de produtividade durante o empreendimento. Da mesma forma, em licitações, orçamentos e estimativas de prazo, a utilização desta técnica permite a adoção de outras estimativas diferentes da produtividade média, que é comumente usada e como alternativa, se sugerem três critérios: produtividade otimista, média e pessimista.The aim of this article is to analyze the feasibility of using Monte Carlo method to estimate productivity in industrial pipes welding of carbon steel based on small samples. The study was carried out through an analysis of a reference sample containing productivity data of 160 welded joints by SMAW process in REDUC (Duque de Caxias Refinery, using ControlTub 5.3 software

  6. Estudo da emissão de raios infravermelho próximo em processos de soldagem a arco Study of near-infrared emission on processes of arc welding

    Carolina Pimenta Mota

    2011-03-01

    Full Text Available O estudo de boa parte dos fenômenos envolvidos no processo de soldagem necessita de auxílio visual e a luminosidade emitida pelo arco pode representar uma grande barreira. Uma das formas utilizadas atualmente para se obter a visualização do processo, sem a interferência do arco, consiste em iluminar o processo com o infravermelho próximo e utilizar filtros durante a aquisição das imagens. Assim, é importante investigar o comportamento do arco de soldagem em relação à sua emissão luminosa no espectro infravermelho. Desta forma, a proposta deste trabalho foi a realização de um estudo comparativo entre a emissão do arco de soldagem de radiação infravermelha próxima em dois processos largamente utilizados, TIG e MIG/MAG, focando também sua influência por parâmetros como a corrente de soldagem e a proteção gasosa utilizada. Com o uso de um sensor de luminosidade e a utilização de um sistema de lentes ópticas, foram realizados experimentos, adquirindo o espectro luminoso emitido pelo arco voltaico. Através dos resultados obtidos, ou seja, do valor numérico de energia luminosa do arco de soldagem (integração do espectro é possível se obter, com a utilização desta mesma metodologia, a energia luminosa no infravermelho próximo e, consequentemente, a intensidade luminosa, necessária para a sobreposição do arco durante a aquisição de imagens.Most of the phenomenon studied in the welding processes needs a vision system and the arc light emission can create a great barrier. Nowadays, one of the techniques used for visualizing the process, without arc interference, is the illumination of the process with near-infrared laser and the use of optic filters during the image acquisition. Thus, it is important to investigate the welding arc behavior in respect to its light emission within the near-infrared spectrum. Therefore, this work aims to perform a comparative study of the arc near infrared emission in one of the two

  7. Comparação da eficiência térmica entre soldagem A-TIG e TIG convencional

    Donegá,Thiago José; Costa,Thonson Ferreira; Arencibia,Rosenda Valdés; Vilarinho,Louriel Oliveira

    2014-01-01

    O processo A-TIG (soldagem TIG com fluxo ativo) consiste em depositar uma fina camada de fluxo sobre a superfície da peça antes da soldagem. A deposição da camada pode ser feita através de pincel ou spray, e a soldagem é realizada após a secagem. Verifica-se que com este processo é possível aumentar a produtividade (velocidade de soldagem) em até três vezes em comparação ao processo TIG convencional. Entretanto, os fenômenos físicos associados a este ganho prático de produtividade ainda perma...

  8. Development of safe optimized welding procedures for high strength Q&T steel welded with austenitic consumables Desenvolvimento de procedimentos de soldagem seguros e otimizados para aços temperados e revenido de alta resistência com consumíveis austeníticos

    Lenka Kuzmikova

    2013-06-01

    Full Text Available High strength quenched and tempered (Q&T steels offer obvious economic benefits originating from their advantageous strength to price and weight ratios. These steels are usually welded using ferritic consumables and for this combination the risk of hydrogen assisted cold cracking (HACC is high. The use of austenitic stainless steel (ASS consumables has great potential to significantly improve this issue. Yet, there are no guidelines for determination of safe level of preheat for welding ferritic steels with ASS consumables. For this reason manufacturers adopt this parameter from procedures developed for conventional ferritic consumables thus significantly limiting the benefits ASS consumables are capable to deliver. Productivity could be further enhanced by identifying the upper interpass temperature threshold, thus reducing the stand-off times. Aim of this work is to develop safe highly optimised procedures for welding of high strength Q&T steel with ASS consumable.Aços temperados e revenidos de alta resistência (Q&T oferecem vantagens econômicas óbvias originadas de sua benéfica razão resistência e custo ou peso. Estes aços são normalmente soldados com consumíveis ferríticos e, por esta causa, apresentam alto risco de trinca de hidrogênio. O uso de consumíveis de aços inoxidáveis austeníticos representa um grande potencial para melhorar este aspecto. Entretanto, não há recomendações técnicas para determinar um nível seguro de temperatura de pré-aquecimento para soldagens de aços ferríticos com consumíveis austeníticos. Por isto, fabricantes adotam para este parâmetro os tirados de procedimentos desenvolvidos para consumíveis ferríticos convencionais, consequentemente reduzindo os benefícios que os consumíveis austeníticos poderiam fornecer. Produtividade poderia ser intensificada pela identificação da temperatura de interpasse, reduzindo os tempos mortos. O objetivo do presente trabalho foi o de desenvolver

  9. Monitoring system for thermal plasma; Sistema de monitoreo para plasma termico

    Romero G, M.; Vilchis P, A.E. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    In the Thermal plasma applications laboratory it has been the degradation project of oils for isolation in transformers. These are a very hazardous residues and at this time in the country they are stored in metal barrels. It has been the intention to undergo the oils to plasma for degradate them to non-hazardous residues. The system behavior must be monitored to establish the thermal plasma behavior. (Author)

  10. Avaliação da microestrutura e propriedades mecânicas de metais de solda obtidos por processos de soldagem manual e automatizado utilizado na soldagem de aço API 5L X80 Evaluation of microstructure and mechanical properties of weld metals obtained by manual and automated welding process used in the welding of API 5L X80 steel

    Siderley Fernandes Albuquerque

    2011-12-01

    Full Text Available O objetivo do trabalho foi avaliar as características da zona termicamente afetada (ZTA e a microestrutura e propriedades mecânicas de metais de solda de juntas soldadas do aço API 5L X80, obtidos para quatro diferentes procedimentos de soldagem utilizando processos manuais e automatizados. Para isto, chapas do referido aço foram soldadas por processo manual ao Arco Elétrico com Eletrodo Revestido (SMAW, utilizando 473 e 673 K como temperaturas de interpasses e o eletrodo celulósico AWS E8010-G como consumível; por processo ao Arco Elétrico com Arame Tubular (FCAW robotizado, utilizando o arame AWS E71T- 1C como metal de adição e argônio com 25%CO2 como gás de proteção; por processo a Arco Elétrico com Eletrodo de Tungstênio (GTAW mecanizado na raiz da solda, usando o arame ER70S-3 e argônio como gás de proteção. As análises microestruturais foram relacionadas com os resultados de ensaios de impacto Charpy nos metais de solda e com os perfis de microdureza Vickers ao longo da junta soldada. Os resultados indicaram maiores percentuais de Ferrita Acicular e maiores valores de resistência ao impacto nos metais de solda e uma menor extensão e granulometria da ZTA, associado ao procedimento de soldagem utilizando processo automatizado com maior velocidade de soldagem.The objective of this work was to evaluate the heat affected zone characteristics and weld metals microstructure and mechanical properties of API 5L X80 steel welded joints, obtained for four different welding procedures using manual and automated processes. For this, plates of this steel were welded by manual Shielded Metal Arc Welding (SMAW process with interpasses temperatures of 473 e 673 K, and using AWS E8010-G electrode as filler metals; robotized Flux Cored Arc Welding (FCAW process, using AWS E71T-1C wire and Ar25%CO2 as consumable and mechanized Gas Tungsten Arc Welding (GTAW process, for the root pass using AWS ER70S-3 and Ar as consumable .The

  11. Estudo de alguns parâmetros básicos da soldagem GMAW com transferência por curto-circuito Evaluation of basic parameters of short-circuit GMA welding

    Paulo J. Modenesi

    2011-03-01

    Full Text Available O processo de soldagem GMAW é caracterizado por uma forte interdependência de seus parâmetros operacionais e uma grande sensibilidade a variações destes. Estas características podem causar variações nas condições operacionais, dificultando o estabelecimento e a reprodução destas condições que, usualmente precisam ser verificadas pela realização de testes. Como uma forma de minimizar esta dificuldade e facilitar o entendimento da relação entre as variáveis deste processo, tem-se trabalhado no desenvolvimento de um modelo matemático capaz de simular aspectos elétricos e operacionais da soldagem GMAW. O objetivo do presente trabalho foi estudar procedimentos de determinação e fatores que afetam duas variáveis fundamentais para o desenvolvimento deste modelo (a resistividade elétrica do arame durante a soldagem e a soma das quedas de tensão anódica e catódica no arco, U AC na soldagem com transferência por curto-circuito. Os testes experimentais envolveram a deposição mecanizada de cordões emaço de baixo carbono usando arames do mesmo material com diferentes gases de proteção. Metodologias para a determinação dos parâmetros citados foram desenvolvidas com base em procedimentos similares indicados na literatura. Os detalhes destes procedimentos são avaliados, os resultados obtidos são comparados com dados da literatura e métodos para estimar a resistência elétrica entre o bico de contato e o eletrodo são apresentados. Os resultados sugerem valores para esta resistência entre 6 e 9 mΩ.GMA welding is characterized by a strong dependence between its operational parameters and a high sensitivity to small variations of those. These characteristics tend to make it harder to replicate welding conditions. It is also a barrier to welding automation and makes it necessary to perform a number of real welding tests before determining operational conditions for a given application. In order to contribute to reduce

  12. Influência do material de base sobre o rendimento de fusão em soldagem a arco Influence of base material on the melting efficiency in arc welding

    Ruham Pablo Reis

    2011-12-01

    Full Text Available O objetivo deste trabalho foi determinar o comportamento do rendimento bruto de fusão em soldagem a arco frente a diferentes tipos de material de base (aço ao carbono, aço inoxidável e alumínio. Como extensão, objetivou-se também estimar de forma indireta o rendimento térmico do processo em questão usando-se estimação de isotermas por método analítico. Para isto, foram feitas soldagens sobre placas de teste utilizando-se o processo TIG nos três materiais em dois níveis de corrente de soldagem. Foi verificado que o rendimento bruto de fusão é muito baixo (menor que 10%, mas tende a aumentar com a elevação do nível de corrente de soldagem (efeito da dimensão da peça. O alumínio apresentou o menor rendimento de fusão, tendo o aço inoxidável apresentado o melhor aproveitamento do calor imposto. Em relação ao rendimento térmico, a metodologia proposta não se mostrou adequada.The aim of this work was to determine the behavior of the gross melting efficiency in arc welding towards different types of materials (carbon steel, stainless steel and aluminum alloy. An extra objective was to indirectly estimate the thermal efficiency of the process using the estimation of isotherms by analytic methods. For that, welds were carried out over three materials at two welding current levels using the GTAW process. It was verified that the melting efficiency is very low (lower than 10%, yet it rises by increasing the current level (effect of material size. The aluminum alloy presented the lowest melting efficiency in contrast to the highest heat yield of the stainless steel. With respect to the thermal efficiency, the proposed methodology was not adequate.

  13. Investigação sobre a eficiência da fibra de vidro e da fibra cerâmica como suporte de solda na soldagem unilateral Investigation over the eficiency of fiber glass and ceramic fiber as weld support in one-sided welding

    Luiz Cláudio Tatagiba

    2011-12-01

    Full Text Available O objetivo deste trabalho foi avaliar uma nova categoria de suporte de solda para a soldagem unilateral do aço carbono, usando tecidos de fibra de vidro e fibra cerâmica. Trata-se de uma proposta de inovação tecnológica, uma evolução do suporte cerâmico convencional. A soldagem unilateral com este tipo de suporte de solda foi executada em chapas de aço carbono com arame tubular (FCAW e MIG-MAG (GMAW. A eficiência da fibra de vidro e da fibra cerâmica em suportar o metal de solda líquido foi verificada durante a soldagem do passe de raiz. Várias espessuras e combinações de tecidos de fibra de vidro e fibra cerâmica foram testadas, bem como foram identificados pontos de trabalho. As seguintes variáveis do processo foram estudadas: a abertura de raiz, a corrente e a velocidade de soldagem. Os resultados mostram que os materiais à base de fibra de vidro e fibra cerâmica são eficientes para suportar a poça de solda líquida. O modo de fixação do suporte de solda na junta soldada também mostrou ser efetivo. Foi possível estimar uma faixa de operação do processo, com abertura de raiz de 2,0 a 4,0 mm, a energia de soldagem menor que 1,8 kJ/mm, a técnica de soldagem ligeiramente puxando e com pequena oscilação da tocha, espessura do suporte de solda de tecido de fibra de vidro maior que 1,6 mm. Macrogafias da juntas soldadas mostraram que houve penetração nas laterais do chanfro, reforço de solda adequado na raiz e não foram notados defeitos.The objective of this work was to evaluate a new chategory of weld support for the one-sided welding of carbon steel, using fiber glass and ceramic fiber tissues. This is a proposal of techonological innovation proposed, an evolution of the conventional ceramic support. The one-sided welding with this type of weld support was made in carbon steel with FCAW and GMAW. The efficiency of fiber glass and ceramic fiber was verified during the root weld bead. Several thicknesses and

  14. Junções de materiais dissimilares utilizando o processo de soldagem por fricção rotativa

    Eder Paduan Alves

    2010-01-01

    O objetivo desse trabalho é o desenvolvimento de junções no estado sólido de materiais dissimilares alumínio AA 1050 e aço inoxidável AISI 304, que possam ser utilizadas nas tubulações de reservatórios de propelentes líquidos e demais tubulações dos Veículos Lançadores de Satélites. As junções foram obtidas pelo processo de soldagem por fricção rotativa convencional, que combina o calor gerado entre o atrito de duas superfícies e deformação mecânica. Foram realizados testes de soldagem com di...

  15. Microwave plasma for materials treatment; Plasmas de microondas para tratamiento de materiales

    Camps, E.; Garcia, J.L.; Muhl, S.; Alvarez F, O.; Chavez C, J. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1997-07-01

    The microwave discharges of the Electron Cyclotron Resonance (Ecr) type are capable to generate plasma with relatively high ionization coefficients which can vary between 1 and 10 % also they are realized in low pressures at 10 {sup -4} Torr. order generating at this time high concentrations of neutral excited chemical species which result in that the chemical processes can be realized with much greater velocity as in another systems. In this work it was studied and characterized a microwave discharge type Ecr using for this electric probes and optical emission spectroscopy. The characterization was carried out with the purpose of optimizing the plasma parameters and to establish a control over the same one doing so that the experiments have a greater reproducibility and a major work efficiency. (Author)

  16. Otimização do processo de soldagem FCAW usando o erro quadrático médio multivariado FCAW welding process optimization using the multivariate mean square error

    Emerson José de Paiva

    2010-03-01

    Full Text Available Encontrar um conjunto ótimo de parâmetros para um processo de soldagem é uma tarefa pouco trivial, face às múltiplas características exigíveis ou desejáveis que devem ser analisadas. Além disso, a negligência da estrutura de variância-covariância destas características na otimização pode conduzir a ótimos inadequados. Com o intuito de auxiliar na busca desses parâmetros, um método para otimização multiobjetiva, desenvolvido para o estudo do processo de soldagem FCAW (do inglês Flux Cored Arc Welding, utilizando-se arames tubulares, baseado no conceito de Erro Quadrático Médio Multivariado, será apresentado. Trata-se de uma abordagem combinada da Metodologia de Superfície de Resposta, Projeto de Experimentos e Análise de Componentes Principais, na tentativa de localizar valores próximos a alvos especificados, para cada uma das características estudadas (Penetração, Taxa de deposição, Rendimento, Índice de convexidade e Diluição, considerando-se as variáveis de processo expressas em função da tensão (V, velocidade de alimentação do arame (Va e da distância do bico de contato-peça (d. Os resultados obtidos apontam para uma boa adequação desta proposta.The optimization of welding processes is not a trivial task, mainly due to the great number of exigible and desirable characteristics that must be analyzed. Moreover, the optimization of a welding process with multiple characteristics without to consider the variance-covariance structure, may lead to inadequate optimum. To help in this task, a method of multiobjective optimization based in the Multivariate Mean Square Error applied in the study of multiple correlated characteristics of a FCAW (Flux Cored Arc Welding welding process will be presented. This method characterized by a combined approach based in the Response Surface Methodology, Design of Experiments and Principal Components Analysis consisted in an attempt to achieve the nearest values to

  17. Robotic system for orbital welding of pipes; Sistema robotizado para soldagem orbital de dutos

    Bracarense, Alexandre Queiroz; Lima, II, Eduardo Jose; Torres, Guilherme Fortunato; Ramalho, Frederico [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Felizardo, Ivanilza; Zanon, Gislaine Pires [ROTECH Tecnologia Robotica Ltda., Belo Horizonte, MG (Brazil)

    2004-07-01

    This work presents the robotic system projected for orbital welding of pipelines of oil and gas. The system consists of a controller (microcomputer), that allows the execution of all the referring tasks to the welding in an autonomous way, and two manipulates, to what are coupled the welding torches that are connected to a welding power source with double wire feeders. With this system, GMA W process is used to execute the root pass, while FCA W process, besides the GMA W, is used for the filling and finishing passes. The system has four degrees of freedom, allowing the control of stick out, travel speed, torch angle and positioning. Besides these, the arc voltage and and welding current are also controlled during the process. Knowing that for each welding position (plane, vertical up and down and over head) a great group of parameters must be used, several tests were accomplished. With these values a controlled variation could be accomplished in an uninterrupted way when welding position changes, getting the increase of the productivity and also the quality of the weld performed by a robotic system. (author)

  18. Análise do fluxo de material no processo de soldagem por fricção com pino consumível

    Renan Mensch Landell

    2016-01-01

    Em substituição aos processos de reparo de defeitos por soldagem por arco elétrico, a Soldagem por Fricção com Pino Consumível ou Friction Hydro Pillar Processing (FHPP) vem sendo estudada devido a suas diversas vantagens sobre os processos convencionais de reparo. Isso se deve a não ocorrência de fusão do metal base e do metal de adição, ao reduzido tempo de processamento (inferior a um minuto, na maioria dos casos) e à possibilidade de automação do processo. Entretanto, por ser um processo ...

  19. Efeitos da Pulsação Ultrassônica da Corrente sobre a Geometria da ZF e ZAC na Soldagem Arco Submerso

    Anna Louise Voigt

    Full Text Available Resumo: O presente trabalho propõe investigar a aplicação da técnica de excitação ultrassônica do arco no processo SAW com o intuito de avaliar a influência dos principais parâmetros associados a pulsação da corrente, como a frequência e a amplitude da corrente de excitação ultrassônica, sobre os cordões de solda produzidos. Para tanto, foi montada uma bancada experimental constituída por duas fontes de energia: uma convencional de soldagem e outra capaz de pulsar a corrente em frequências ultrassônicas. Durante a realização dos ensaios foram empregadas duas amplitudes de corrente de excitação ultrassônica, 25 A e 50 A, cada qual em três frequências de pulsação diferentes, 20 kHz, 50 kHz e 80 kHz. A partir de macrografias foram realizadas análises dimensionais dos cordões obtidos com foco na largura, penetração e área fundida, assim como a área da zona afetada pelo calor (ZAC. Como resultado, contrariando as informações disponíveis na literatura, não foi possível identificar alterações consideráveis na geometria do cordão de solda, assim como, na ZAC que pudessem ser atribuídas à pulsação da corrente nas frequências estudadas.

  20. Analysis of Magnetic Nozzles For Space Plasma Thrusters = Análisis de Toberas Magnéticas para Motores Espaciales de Plasma

    Merino Martínez, Mario

    2013-01-01

    Esta tesis presenta un análisis teórico del funcionamiento de toberas magnéticas para la propulsión espacial por plasmas. El estudio está basado en un modelo tridimensional y bi-fluido de la expansión supersónica de un plasma caliente en un campo magnético divergente. El modelo básico es ampliado progresivamente con la inclusión de términos convectivos dominantes de electrones, el campo magnético inducido por el plasma, poblaciones electrónicas múltiples a distintas temperaturas, y la capacid...

  1. A química da formação do cordão na soldagem TIG

    Paulo J. Modenesi

    2013-09-01

    Full Text Available A soldagem TIG apresenta elevados níveis de estabilidade e permite um controle mais apurado do que a maioria dos demais processos de soldagem a arco. É bem conhecido, contudo, que pequenas variações de composição química do metal base ou da região de operação do arco podem ter um efeito pronunciado no formato do cordão de solda, o que reduz a capacidade de controlar e a previsibilidade do processo. Este trabalho apresenta uma revisão da variabilidade do cordão de solda obtido no processo TIG com pequenas alterações na composição química do metal base e das soldagens A-TIG e TIG com gás ativo. Aspectos comuns e particulares de cada caso são realçados e discutidos e os mecanismos propostos na literatura em cada caso são apresentados e comparados.

  2. Avaliação da precisão de duas técnicas de união de estruturas metálicas - brasagem e soldagem a laser - em uma prótese clássica de Brånemark pelo método da microscopia eletrônica de varredura (MEV)

    Lucio Hirokuni Kanashiro

    2005-01-01

    Este estudo avaliou a precisão de duas técnicas de união, a brasagem e a soldagem a laser, em estruturas metálicas de uma prótese clássica de Brånemark. Dez estruturas fundidas em NiCr foram segmentadas em 4 partes e analisadas no MEV em pontos pré-estabelecidos, vestibular e proximal, totalizando 8 pontos de análise para cada estrutura. Na primeira fase, foi mensurada a fenda marginal existente entre o análogo do implante e o abutment UCLA antes da união destes segmentos através da brasagem ...

  3. In-situ-phase analysis using synchrotron radiation of low transformation temperature (LTT welding material Análise "In-Situ" de fases com radiação sincrótona de materiais de soldagem de baixa temperatura de transformação

    Arne Kromm

    2009-03-01

    Full Text Available Cold cracking resistance is a relevant evaluation criterion for welded joints and affected by residual stresses which result from the welding procedure. Compressive residual stresses can thereby have a positive influence on preventing cracking. A unique possibility of generating compressive residual stresses already during the welding procedure is offered by the so-called Low Transformation Temperature (LTT filler wires. Compared to conventional wires, these materials show decreased phase transformation temperatures which can work against the cooling-specific contraction. In consequence, distinct compressive residual stresses can be observed within the weld and adjacent areas. The strength of these fillers makes them potentially applicable to high-strength steel welding. Investigations were carried out to determine the phase transformation behaviour of different LTT-filler materials. Transformation temperatures were identified using Single Sensor Differential Thermal Analysis (SS-DTA. Additionally Synchrotron radiation was used to measure the transformation kinetics of all involved crystalline phases during heating and cooling of a simulated weld thermal cycle.Fissuração a frio é um critério de avaliação relevante para juntas soldadas, sendo afetada pelas tensões residuais resultantes da soldagem. Neste contexto, tensões residuais de compressão podem ter uma influência positiva no sentido de prevenir a fissuração. Uma possibilidade única de já gerar tensões residuais de compressão já durante a execução da soldagem é oferecida pelos materiais de adição conhecidos como de "baixa temperatura de transformação" (BTT. Comparados com metais de adição convencionais, esses apresentam uma temperatura de transformação de fase inferior a qual pode contrapor a contração térmica do material durante o seu resfriamento. Como resultado, claras tensões residuais compressivas podem ser observadas na soldas e áreas adjacentes. A

  4. The international institute of welding (IIW, its potential positive influence in the world and some national models for technology innovation O instituto internacional de soldagem (IIS, sua influência potencial positiva no mundo e alguns modelos nacionais de inovação tecnológica

    Chris Smallbone

    2009-03-01

    industry, education and training, improving the image of welding and the use of appropriate technologies will be highlighted. Examples of how the elements of such models could be used in many regions of the world will be given. The involvement of industry and governments across the world in conjunction with the work of IIW and its 53 member countries is critical to the success of such initiatives.Desde a sua criação 60 anos atrás, o Instituto Internacional de Soldagem (IIS teve muitos casos de sucesso. Em 2006, o IIS introduziu um grande projeto denominado "Melhorar a Qualidade de Vida Global Através do Uso Otimizado da tecnologia de Soldagem". Muitas de suas iniciativas beneficiarão vários países. Estima-se que, nesta próxima década, muitos trilhões de dólares serão gastos em projetos de infra-estrutura em indústrias de energia e de processamento. Além de trabalhos de usuais de fabricação, construção e manutenção, os projetos adicionais de infra-estrutura criarão desafios para a tecnologia de soldagem. Estes desafios incluem a fabricação, construção, manutenção inspeção e avaliação de trilhões de componentes de forma eficiente e efetiva, de uma maneira não agressiva ao ambiente e que resulte em elevada integridade e confiabilidade em serviço. Em muitos países industrializados, equipamentos de pressão estão envelhecendo e a vida útil de plantas industriais está sendo levada além do projetado inicialmente. Muitas fábricas estão operando de forma quase ininterrupta com tempo muito limitado para inspeção e manutenção. Isto é uma receita para o desastre. Espera-se que, nos próximos cinco anos, um número crescente de falhas, resultando em morte, ferimentos, danos ao ambiente e perda de produção, ocorrerá através do mundo. Este artigo dá uma visão geral do trabalho do IIS em diferentes regiões do mundo e setores industriais que usam a soldagem, os desafios encontrados, oportunidades disponíveis, oportunidades dispon

  5. Influência da energia de soldagem em uniões de lâminas finas através de laser pulsado de Nd:YAG Effect of the heat input on pulsed Nd:YAG laser welding of thin foil

    Vicente A. Ventrella

    2010-12-01

    Full Text Available A soldagem laser vem sendo utilizada como um importante processo de manufatura. Ela pode ser utilizada tanto no modo contínuo quanto no modo pulsado. No processo onde se utiliza laser pulsado é possível realizar soldas de costura em lâminas finas, através da sobreposição dos pulsos. Nesse caso a velocidade de soldagem é definida pela taxa de sobreposição, taxa de repetição e diâmetro do pulso. A soldagem de sobreposição de lâminas finas apresenta problemas típicos como distorção excessiva da junta soldada, falta de contato entre as lâminas a serem soldadas (presença de um gap de ar, perfuração da junta e presença de altos níveis de tensões residuais. O processo de laser pulsado é preferido em relação ao processo por laser contínuo, pois ele possibilita um melhor controle da energia de soldagem. O presente trabalho estudou a influência da energia do pulso, no caso processo de soldagem laser Nd:YAG, na soldagem de lâminas finas ( 100µm de aço inoxidável austenítico AISI 316L, utilizado no revestimento de sensores (que trabalham em ambiente corrosivo da indústria sucroalcooleira. Utilizou-se energia de pulso de 1,0 a 2,25 Joules, com incremento de 0,25 Joules e largura temporal de 4 ms. As soldas foram realizadas com proteção gasosa de argônio. Foram realizadas análises macrográficas das juntas soldadas, através de secções transversais das mesmas e, ensaios de microdureza Vickers e ensaios de tração. Os resultados obtidos mostraram que o controle da energia do pulso, em processo de soldagem por laser de lâminas finas é de fundamental importância para a geração de juntas soldadas com boas propriedades mecânicas e livres de descontinuidades. O limite de resistência da junta soldada aumentou no início e depois sofreu um pequeno decréscimo em função do aumento da energia do pulso. O processo mostrou-se muito sensível à presença de gap entre as lâminas.Laser beam welding has been used widely

  6. Power supply controlled for plasma torch generation; Fuente de alimentacion controlada para la generacion de un plasma

    Diaz Z, S

    1997-12-31

    The high density of energy furnished by thermal plasma is profited in a wide range of applications, such as those related with welding fusion, spray coating and at the present in waste destruction. The waste destruction by plasma is a very attractive process because the remaining products are formed by inert glassy grains and non-toxic gases. The main characteristics of thermal plasmas are presented in this work. Techniques based on power electronics are utilized to achieve a good performance in thermal plasma generation. This work shown the design and construction of three phase control system for electric supply of thermal plasma torch, with 250 kw of capacity, as a part of the project named `Destruction of hazard wastes by thermal plasma` actually working in the Instituto Nacional de Investigaciones Nucleares (ININ). The characteristics of thermal plasma and its generation are treated in the first chapter. The A C controllers by thyristors applied in three phase arrays are described in the chapter II, talking into account the power transformer, rectifiers bank and aliasing coil. The chapter III is dedicated in the design of the trigger module which controls the plasma current by varying the trigger angle of the SCR`s; the protection and isolating unit are also presented in this chapter. The results and conclusions are discussed in chapter IV. (Author).

  7. Soldagem em operação: parte 1 - efeito do arrefecimento causado pelo fluido em tubulação de espessura 11 mm In-service welding: part 1: effect of freezing caused by fluid in 11 mm thick pipe

    Paulo Faria

    2012-12-01

    Full Text Available Este trabalho avalia, na soldagem em operação, a influência do arrefecimento causado por um líquido fluindo em contato com a parede interna de uma tubulação sendo soldada por TIG (GTAW e eletrodo revestido (SMAW. A soldagem foi realizada na ligação de conexões de aço ASTM A105 a um tubo API 5L Gr X60 com espessura de 11 mm e de 6 mm. A circulação do fluido foi feita com água potável em duas faixas de temperatura, de 6 a 10ºC e 26 a 36ºC. Foram simuladas quatro juntas soldadas, avaliadas por meio de ensaios não destrutivos (inspeção visual, líquido penetrante, partículas magnéticas e ultrasom. Esta parte do trabalho apresenta os resultados dos ensaios destrutivos (tração, dobramento, impacto, fratura e dureza e análise macrográfica e micrográfica para o tubo de 11 mm de espessura. As juntas soldadas não apresentaram os problemas típicos da soldagem em operação, como trincas a frio e risco de perfuração. Os procedimentos de soldagem puderam ser qualificados, atendendo os critérios de aceitação das normas pertinentes. Foi possível concluir que o resfriamento acelerado causado pelo fluido em circulação, elevou consideravelmente a taxa de resfriamento na superfície interna do tubo. O efeito do arrefecimento causado pelo fluido no interior do tubo foi mais significativo que a temperatura deste fluido, tendo provocado o aumento na dureza da zona fundida e zona termicamente afetada e reduzido o alongamento no ensaio de tração, porém ainda em valores adequados para o tubo de 11 mm de espessura.This work evaluates for in-service welding, the influence of cooling caused by a liquid flowing in contact with the inner wall of a pipe being welded by TIG (GTAW and stick electrode (SMAW. The welding was done to join connections of an ASTM A105 to an 11mm and 6 mm thick API 5L Gr X60 steel pipe. The fluid circulation was made with potable water within two temperature ranges, of 6 to 10ºC and 26 to 36ºC. Four welded

  8. Estudo comparativo da resistência ao desgaste abrasivo do revestimento de três ligas metálicas utilizadas na indústria, aplicadas por soldagem com arames tubulares Comparative study of the wear resistance of three metal cored wire welded coatings used in industry

    Ricardo Vinícius de Melo Leite

    2009-12-01

    Full Text Available As ligas metálicas aplicadas por soldagem em superfícies, objetivando a proteção contra o desgaste e o conseqüente aumento da vida útil de peças e equipamentos, têm sido utilizadas em larga escala nas indústrias de bens de consumo e nos setores de mineração e sucroalcooleiro. O desgaste abrasivo em peças e equipamentos representa, nestas industriais, um dos principais fatores de depreciação de capital e uma importante fonte de despesas com manutenção. Para a aplicação do revestimento por soldagem, os arames tubulares têm sido uma alternativa cada vez mais viável, devido à sua alta produtividade e qualidade de solda, substituindo, em parte, o uso do eletrodo revestido. O objetivo deste trabalho é fazer um estudo comparativo da resistência ao desgaste abrasivo do revestimento aplicado por soldagem com arames tubulares autoprotegidos de três ligas metálicas utilizadas na indústria, uma do tipo Fe-Cr-C, outra do tipo Fe-Cr-C com adição de nióbio e boro e a terceira, do tipo Fe-Cr-C com adição de nióbio. Os revestimentos anti-desgaste, conhecidos como revestimento duro, foram aplicados em chapas de aço carbono, com os mesmos parâmetros e procedimentos de soldagem. Os corpos de prova foram obtidos por corte e retificação e foram submetidos a ensaios de desgaste abrasivo, em um abrasômero Roda de Borracha, conforme procedimento estabelecido pela norma ASTM G65-91. Os resultados obtidos demonstraram que a liga Fe-Cr-C com adição de Nióbio e Boro apresentou desempenho superior em relação ao desgaste abrasivo.The metal alloys deposited by welding on the components surface, with the objective of protection against wear and the consequent increase in the lifetime of parts and equipments, have been used extensively in the consumer products industry and sectors of Mining and Sugar & alcohol. The abrasive wear on parts and equipments represents one of the main depreciation factors of capital and the major source of

  9. Influência da energia de soldagem na microestrutura e na microdureza de revestimentos de aço inoxidável duplex Influence of the heat input on the microstructure and microhardness of weld overlay of duplex stainless steel

    Everton Barbosa Nunes

    2012-06-01

    Full Text Available Aços inoxidáveis duplex (AID são caracterizados por apresentar interessante boas propriedades mecânicas e resistência à corrosão, possuindo um vasto campo de aplicação na indústria química e petroquímica. Geralmente, os reparos dos equipamentos ou estruturas são realizados por soldagem, sendo importante a seleção de parâmetros. É de suma importância a obtenção do teor adequado de ferrita no metal de solda, sendo que a variação da energia de soldagem pode influenciar de forma direta no percentual de ferrita. Logo, o objetivo deste trabalho é avaliar a influência da variação da energia de soldagem na microestrutura e na microdureza do metal de solda do AID. Foram realizadas soldagens de revestimento com sobreposição de duas camadas sobre o aço estrutural ASTM A516 Gr.60, utilizando eletrodo revestido AWS E2209-17. Três níveis de energia (15, 20 e 24 kJ/cm foram empregados, variando-se a corrente e a velocidade de soldagem. Foi verificado que para os níveis de energia empregados não houve diferença significativa no percentual de ferrita, porém o primeiro cordão depositado apresentou maior teor de austenita em relação aos demais cordões. De forma geral, foi verificado que o primeiro cordão depositado obteve níveis maiores de microdureza. Todas as condições apresentaram microdurezas abaixo do valor crítico.Duplex stainless steels (DSS are characterized by the presentation of an interesting combination of good mechanical properties and corrosion resistance, having a wide application in chemical and petrochemical industry. Generally, the manufacture and repair of any industrial equipment involve welding operations, even though it is very important to evaluate the influence of welding parameters. It is very important to obtain appropriate ferrite content in the weld metal, so that the variation of heat input can influence on the ferrite content directly. Therefore, the aim this work is to evaluate the

  10. Modelagem matemática do processo de soldagem GMAW: transferência por vôo livre Mathematical modeling of GMA welding: free fligth transfer

    Ivan José de Santana

    2011-09-01

    Full Text Available Este artigo descreve a concepção e validação de um modelo matemático direcionado à soldagem GMAW. O modelo permite a predição de alguns parâmetros de soldagem, assim como o comportamento do processo em condições operacionais de transferência metálica por vôo livre. Este modelo foi baseado em um conjunto de equações, que descrevem as características operacionais da fonte de energia, as quedas de tensão que ocorrem no arco elétrico e nos componentes do circuito de soldagem, e em um balanço de energia na ponta do arame. A validação do modelo envolveu testes de soldagem mecanizada em corpos-de-prova de aço baixo carbono, com monitoração da corrente, tensão, comprimento de arco e velocidade de alimentação de arame. O modelo mostrou-se capaz de prever,em diferentes situações, com erros inferiores a 10%, os valores médios de alguns parâmetros fundamentais no processo de soldagem GMAW (valores médios de corrente, tensão e comprimento de arco elétrico, assim como, o comportamento destes na ocorrência de mudanças operacionais.This paper describes the conception and validation of a mathematical model applied to GMA welding. This model allows predicting some welding parameters as well as process behavior for operation with free flight transfer mode. This model was based on a set of equations that describes the power source characteristics, the voltage drop along the electric arc, the welding circuit and the energy balance on the wire tip. The model validation was performed by comparing its results to experimental welding trials. In this test specimen steel of low carbon was used and the parameters welding current and voltage, speed of wire feeding and arc length were monitored. The results have shown that the model is able to correctly predict how different parameters change with alterations in wire feed, in different situations. Furthermore, welding current and voltage e arc length value were predicted with a least

  11. Quantitative Characterization of Phosphor Detector for Fusion Plasmas; Caracterizacion Cuantitativa de Detectores Luminiscentes para Plasmas de Fusion

    Baciero, A; Zurro, B; McCarthy, K J

    2004-07-01

    Experiments made to characterize phosphor screens with application as broadband radiation detectors, are described. Several radiation sources, covering the spectral range between the ultraviolet and X ray, were used. In addition, details are given of three original phosphor-screen-based detectors that were designed for use as broadband detectors in magnetically confined fusion devices. The first measurements obtained with these detectors in plasmas created in the TJ-II stellarator device are presented together with the analysis performed. (Author)

  12. Soldagem unilateral com suporte cerâmico de cordierita One-sided welding with cordierite ceramic backing

    Luciana Lezira Pereira de Almeida

    2010-06-01

    Full Text Available Este trabalho apresenta a avaliação de juntas soldadas com suporte cerâmico de cordierita produzido em laboratorio. Foi utilizada a técnica de soldagem unilateral em chapas de aço A-36 com espessuras de 6,4 e 15,8 mm pelo processo MIG-MAG. Com a chapa de 6,4 mm foi avalliado apenas o passe de raiz sobre o suporte cerâmico. Com a chapa de 15,8 mm foi produzida uma junta soldada em passes múltiplos. Após soldagem as juntas soldadas foram submetidas a ensaios de inspeção visual, liquido penetrante, macrografia, microdureza Vickers, microscopia ótica, ensaios de dobramento e de tração e análise química por EDS. Os resultados mostram que o passe de raiz, realizado sobre o suporte cerâmico, apresentou bom acabamento, isento de descontinuidades, com penetração adequada nas laterais do chanfro e reforço de solda apropriado. Em relação à junta soldada, a microestrutura da zona fundida (ZF obteve predominância de ferrita primária, em suas formas de ferrita de contorno de grão e poligonal, e ferrita com segunda fase alinhada. A microdureza Vickers obteve valores médios abaixo de 180 HV tanto na zona termicamente afetada (ZTA como na ZF. Os ensaios de dobramento não apresentaram descontinuidades maiores que 3 mm e nos ensaios de tração a ruptura ocorreu no metal base, indicando que o procedimento de soldagem foi adequado. A composição das inclusões tanto do passe de raiz como do ultimo passe de solda possuem os mesmos constituintes, apesar de proporções diferentes, indicando que não houve contaminação do material do suporte cerâmico no cordão de solda.This work presents the evaluation of welded joints using ceramic backing made in the laboratory. The one-sided welding technique was used to weld A-36 steel plate with 6,4 and 15,8 mm thick by the GMAW process. With the 6,4 mm steel plate, only the root bead welded over the ceramic backing was evaluated. With the 15,8 mm steel plate, a multipass welded joint was made

  13. Soldagem unilateral com suporte cerâmico de cordierita One-sided welding with cordierite ceramic backing

    Luciana Lezira Pereira de Almeida

    2010-03-01

    Full Text Available Este trabalho apresenta a avaliação de juntas soldadas com suporte cerâmico de cordierita produzido em laboratorio. Foi utilizada a técnica de soldagem unilateral em chapas de aço A-36 com espessuras de 6,4 e 15,8 mm pelo processo MIG-MAG. Com a chapa de 6,4 mm foi avalliado apenas o passe de raiz sobre o suporte cerâmico. Com a chapa de 15,8 mm foi produzida uma junta soldada em passes múltiplos. Após soldagem as juntas soldadas foram submetidas a ensaios de inspeção visual, liquido penetrante, macrografia, microdureza Vickers, microscopia ótica, ensaios de dobramento e de tração e análise química por EDS. Os resultados mostram que o passe de raiz, realizado sobre o suporte cerâmico, apresentou bom acabamento, isento de descontinuidades, com penetração adequada nas laterais do chanfro e reforço de solda apropriado. Em relação à junta soldada, a microestrutura da zona fundida (ZF obteve predominância de ferrita primária, em suas formas de ferrita de contorno de grão e poligonal, e ferrita com segunda fase alinhada. A microdureza Vickers obteve valores médios abaixo de 180 HV tanto na zona termicamente afetada (ZTA como na ZF. Os ensaios de dobramento não apresentaram descontinuidades maiores que 3 mm e nos ensaios de tração a ruptura ocorreu no metal base, indicando que o procedimento de soldagem foi adequado. A composição das inclusões tanto do passe de raiz como do ultimo passe de solda possuem os mesmos constituintes, apesar de proporções diferentes, indicando que não houve contaminação do material do suporte cerâmico no cordão de solda.This work presents the evaluation of welded joints using ceramic backing made in the laboratory. The one-sided welding technique was used to weld A-36 steel plate with 6,4 and 15,8 mm thick by the GMAW process. With the 6,4 mm steel plate, only the root bead welded over the ceramic backing was evaluated. With the 15,8 mm steel plate, a multipass welded joint was made

  14. Avaliação do Uso do Tecimento sobre o Nível de Diluição e Geometria do Cordão de Solda na Soldagem TIG com Alimentação Automática de Arame Frio

    Edvan Cordeiro de Miranda

    2015-06-01

    Full Text Available ResumoEste trabalho tem por objetivo estudar a influência do tecimento na soldagem TIG com alimentação de arame frio em único passe visando à aplicação futura em revestimento de ligas de níquel, considerando a análise das características geométricas e diluição, de forma a adequar estes revestimentos para as indústrias do Setor de Petróleo e Gás Natural. A baixa diluição é necessária para evitar a redução das propriedades de resistência à corrosão dos revestimentos. As soldagens foram realizadas utilizando um robô industrial e um alimentador automático de arame frio. A liga usada como metal de adição foi a AWS ER NiCrMo-3 (Inconel 625 e o substrato foi o aço ASTM A516 Gr. 60. Foram realizadas soldagens com alimentação automática de arame frio na condição sem tecimento e com tecimento tipo triangular, variando a energia em três níveis. Os resultados mostraram que o uso do tecimento influencia consideravelmente a geometria do cordão de solda e o nível de diluição. Com uso do tecimento o reforço do cordão de solda reduziu e a largura aumentou, proporcionando uma melhor distribuição de material sobre a peça, reduzindo com isso a razão reforço/largura (R/L, parâmetro este que indica o grau de convexidade do cordão de solda. Uma razão R/L alta, indica que o grau de convexidade pode ser excessivo, dificultando com isso uma adequada sobreposição de passes para soldagem posterior de revestimentos, com a possibilidade de formação de vazios entre os mesmos. Quanto a penetração e a diluição, ambas apresentaram comportamentos similares, com redução de forma significativa nas condições em que o tecimento é empregado. Estes resultados mostram que o uso do tecimento garante uma combinação de baixa razão R/L com baixa diluição, condição esta desejável para soldagem de revestimentos.

  15. APLICACIÓN DEL MÉTODO DE COÁGULO DE PLASMA PARA ESTUDIOS DE ULTRAESTRUCTURA CELULAR APPLICATION OF PLASMA COAGULATE METHOD FOR CELULAR ULTRASTRUCTURE STUDIES

    GERARDO ANDRÉS TORRES RODRÍGUEZ

    2009-06-01

    Full Text Available Los estudios de ultraestructura celular en material particulado como bacterias, virus y células en suspensión requieren de un manejo especial, es por esto que se han desarrollado técnicas como la de coágulo de plasma, la cual se aplicó en un modelo experimental de fagocitosis. Se realizaron análisis de Microscopia Electrónica de Transmisión y de Barrido observándose claramente cuatro etapas de la fagocitosis. Se consideró una relación de 10 partículas de levadura por PMN como la proporción más eficiente para la observación del proceso fagocítico, igualmente se determinó muy corto el periodo de incubación de 20 minutos para alcanzar la fagocitosis en su totalidad. La técnica del coágulo de plasma mostró muy buenos resultados en preparaciones para TEM conservando la integridad de las células, no obstante, esta técnica presentó inconvenientes al observarse en MEB debido a los componentes fibrosos del coágulo que impiden una observación de la muestra, adhiriéndose a las superficies produciendo artefactos y deterioro en éstas.Studying ultrastructure cell in particle material such as bacteria, virus and cells suspension require special handling. For that reason, it has been developed techniques like plasma coagulate with phagocytosis as experimental model and analyzed by transmission electronic microscopy (TEM and scanning electronic microscopy (SEM. Four stages of phagocytosis were observed. The efficient proportion to observe the phagocytosis process was 10 particles per NPM (Nuclear Polymorphic, although 20 min as a incubation period was very short to reaching the total process. Applying this technique, cells conserved their integrity to obtain good quality preparation for TEM. In contrast for SEM samples which kept coagulate fiber components adhered to the surface, producing devices and cell deterioration was observed.

  16. Half bridge resonant converter for ignition of thermal plasmas; Convertidor resonante de medio puente para la ignicion de plasmas termicos

    Pena E, L

    1998-12-31

    In this work the background, design, implementation and performance of a half bridge resonant converter (HBRC) used as an electronic ignition system for arc plasma torch generation is presented. The significance of the design lies in its simplicity, versatility and low cost. The system operates like a high voltage supply attached to electrodes before gaseous breakdown and like open circuit when electric arc is established. Resonant converter is implemented with a high voltage and high speed power driver intended for control the power MOSFET transistors connected in half bridge topology with L C load. The HBRC operates besides interference into domestic electric supply line (120 V, 60 Hz) as well electric measurement devices. Advantages and limitations of the converter are reviewed. Experimental impedance variation in the medium as a function of frequency operation and some experiences in striking arcs are also presented. (Author).

  17. Terapia de bioestimulación con plasma rico en plaquetas para el envejecimiento cutáneo Bioestimulation technique with rich plasma in platelets for skin aging

    HM Escobar

    2012-01-01

    La bioestimulación con plasma rico en plaquetas es una técnica ambulatoria para la prevención y manejo del envejecimiento cutáneo, se basa en la fisiología de la piel y funciona muy bien sola o dentro de un plan terapéutico combinado. El derivado de sangre autóloga estimula la producción de colágeno, elastina y tejido epidérmico, lo que se traduce en piel más tersa, luminosa y de mejor calidad. Son mínimos los riesgos de formación de hematomas, infección, transmisión de enfermedades o reaccio...

  18. Pulse generator for bias materials in the plasma immerse ion implantation process; Generador de pulsos para polarizar materiales en el proceso de implantacion de iones inmersos en plasma

    Lopez Callegas, Regulo; Valencia Alvarado, Raul; Munoz Castro, Arturo Eduardo; Godoy Cabrera, Oscar Gerardo [Instituto Nacional de Investigaciones Nucleares, Mexico D.F. (Mexico); Moreno Saavedra, Hilda; Gonzalez Colin, Mireya; Mariano Escamilla, Hector Fernando [Instituto Tecnologico de Toluca, Estado de Mexico (Mexico)

    2003-10-15

    The 0-10 kV pulse generator has been designed, with 100 {mu}s duration and 1-100 Hz frequencies ranges. The use of the pulse generator is in the plasma immersed ion implantation technique (P III). The process was realized in 304 austenitic stainless steel, the results were analyzed by: SEM, X-rays diffraction and hardness Vickers. The hardness was increased due to the efficiency of the pulse generator and P III process, the results obtained showed that the nitrogen inside the stainless steel was implanted and besides some nitrides was formed and therefore the hardness was increased. Also, the more adequate work pressure was determined to carry out the P III process. [Spanish] Se presenta el diseno de un generador de pulsos de alto voltaje con amplitudes controladas de hasta 10 kV, la duracion maxima de los pulsos es del orden de los 100 {mu}s y frecuencia de repeticion en el intervalo de 1-100 Hz. La aplicacion de este generador de pulsos es para el proceso de implantacion de iones en materiales inmersos en plasmas (PIII). Los analisis hechos a los aceros austeniticos cedula 304 mediante microscopia electronica de barrido, difraccion de rayos X y dureza Vickers, muestran la eficiencia obtenida con el generador de pulsos en el proceso PIII, debido a que en el acero inoxidable se presenta un incremento en el nitrogeno y conformacion de algunos nitruros, lo cual da lugar al incremento de la dureza. Asimismo, se determino la presion de trabajo mas adecuada para llevar a cabo el proceso PIII.

  19. Surface preparation for XRD residual stress measurements; Preparacao de superficie para medicao de tensoes residuais em soldagem por DRX

    Mishchenko, Andrii; Oliveira, Bruno Jose de; Scotti, Americo, E-mail: asmwelder@gmail.com, E-mail: brunojoliveira7@gmail.com, E-mail: ascotti@mecanica.ufu.br [Universidade Federal de Uberlandia (UFU), MG (Brazil)

    2016-10-15

    A characteristic feature of the X Ray Diffraction (XRD) method for stress determination is that measurements occur at a thin surface layer. Steel sheets come with surfaces modified by lamination, cleaning (sandblasting, grinding) and even corrosion, which induce residual stresses or roughness inherent to the material. Therefore, surface preparation prior to the residual stress measurement is essential, although no standard procedure seems to be available. A general recommendation is to remove a thin layer so that only residual stresses related to the welding process will be measured. In this study, the use of portable electrolytic equipment was evaluated for mechanized surface material removal. Chemical compositions of electrolytic solutions and the influence of current on the removed material, removal time and temperature during the process were studied. As a result, a suitable chemical solution for electro etching of low carbon steel was developed and a set of “soft” parameters that allowed the removal of about 300 um in a reasonable time was found. Higher currents reduce the removal time, yet increasing the consumption of the solution and plate temperature (which could adversely alter the microstructure or generate thermal stresses). Furthermore, the influence of these parameters on the operability of the process was demonstrated. (author)

  20. Avaliação da soldagem multipasse de chapas espessas de aços inoxidáveis lean duplex UNS S32304 soldadas pelos processos SMAW, GMAW e FCAW: parte 1: propriedades mecânicas Evaluation of multipass welding of thick lean duplex stainless steel UNS S32304 plates welded by SMAW, GMAW and FCAW: part 1: Mechanical Properties

    Ronaldo Cardoso Junior

    2012-12-01

    Full Text Available Os aços inoxidáveis duplex (AID vêm se apresentando como uma excelente alternativa para aplicações em que alta resistência à corrosão e alta resistência mecânica são requeridas. Contudo, os AID, incluindo os aços inoxidáveis lean duplex, apresentam soldabilidade inferior em relação aos aços inoxidáveis austeníticos. Nesse sentido, esse trabalho tem como objetivo a avaliação da soldagem multipasse de chapas 22 mm de espessura da liga inoxidável lean duplex UNS S32304, utilizando-se os processo SMAW, GMAW e FCAW e consumíveis com dois tipos de composição química, 22%Cr9%Ni3%Mo e 23%Cr7%Ni, totalizando seis experimentos. Foram empregados chanfros em V com 60º e suporte cerâmico para soldagem do passe de raiz, sendo que o aporte térmico foi mantido praticamente constante em 1,6 kJ.mm-1. Determinou-se os tempos de soldagem e a seqüência de passes, objetivando uma análise de produtividade, em seguida as juntas soldadas foram submetidas à END por raios x. Foram extraídos corpos de prova para ensaios de tração, dobramento, Charpy a -30 ºC e microdureza. A produtividade dos processos semi-automáticos se mostrou pelo menos 63 % maior que a do processo SMAW, enquanto o processo FCAW se mostrou de 6 a 18% mais rápido que o GMAW. Foram encontradas descontinuidades (porosidade consideradas aceitáveis segundo ASME B31.3 em alguns dos experimentos, que não influenciaram negativamente os resultados mecânicos, os quais se apresentaram acima requerimento do metal de base e especificado por normas de fabricação.The duplex stainless steels (DSS's have been placed as an excellent alternative for applications where high corrosion resistance and high mechanical strength are required. However, DSS's, including the lean duplex, present lower weldability than the austenitic stainless steels. Thus, this study aims to evaluate the multipass welding of 22 mm plates of lean duplex stainless steel alloy UNS S32304, using the process

  1. Terapia de bioestimulación con plasma rico en plaquetas para el envejecimiento cutáneo Bioestimulation technique with rich plasma in platelets for skin aging

    HM Escobar

    2012-03-01

    Full Text Available La bioestimulación con plasma rico en plaquetas es una técnica ambulatoria para la prevención y manejo del envejecimiento cutáneo, se basa en la fisiología de la piel y funciona muy bien sola o dentro de un plan terapéutico combinado. El derivado de sangre autóloga estimula la producción de colágeno, elastina y tejido epidérmico, lo que se traduce en piel más tersa, luminosa y de mejor calidad. Son mínimos los riesgos de formación de hematomas, infección, transmisión de enfermedades o reacciones alérgicas.Biostimulation with rich plasma in platelets is an outpatient technique for the prevention and management of skin aging, which is based on the physiology of the skin, and works very well alone or in a combined treatment plan. Own patient derivate blood stimulates production of collagen, elastin and skin tissue, resulting in a smoother skin, brighter and better quality. Risks of bruising, infection, disease transmission or allergic reactions are minimal.

  2. Efeito dos parâmetros de processo na obtenção e na microestrutura de juntas alumínio-aço realizadas mediante soldagem por atrito com pino não consumível (SAPNC

    Edwar Andrés Torres López

    2013-09-01

    Full Text Available Os resultados bem-sucedidos apresentados na literatura acerca da soldagem por atrito com pino não consumível das juntas alumínio-aço, desconsideram o aspecto e formação de defeitos na junta como pontos de referência para sua avaliação. Igualmente aumenta a controvérsia acerca da presença de compostos intermetálicos do tipo Fe xAl y, somado à falta de informação sobre sua origem. O objetivo deste trabalho é determinar parâmetros adequados para a obtenção de juntas alumínio-aço livres de defeitos e sua relação com a formação de fases deletérias durante a soldagem por atrito com pino. Foram obtidas juntas soldadas consolidadas e foi determinada a microestrutura resultante destas juntas soldadas da liga de alumínio 6063-T5 e aço AISI SAE 1020. Utilizou-se uma ferramenta de carbeto de tungstênio (WC-14Co a velocidades de rotação e de avanço de 300 rpm e 150 mm.min-1, respectivamente. Foram empregados deslocamentos da ferramenta de +0,5; +1,0 e +1,5 mm. Os resultados realçam a importância do aporte energético na obtenção de juntas alumínio-aço com aspecto superficial e penetração adequados. A análise microestrutural revela a formação de sete regiões na junta soldada, destacando a zona termo-mecanicamente afetada no lado do aço, uma banda de grãos ultra finos de ferrita e a ausência de compostos intermetálicos na interface alumínio-aço.

  3. The ortho:para ratio of H{sub 3}{sup +} in laboratory and astrophysical plasmas

    Crabtree, Kyle N.; Indriolo, Nick; Kreckel, Holger; McCall, Benjamin J. [University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2015-01-22

    The discovery of H{sub 3}{sup +} in the diffuse interstellar medium has dramatically changed our view of the cosmic-ray ionization rate in diffuse molecular clouds. However, another surprise has been that the ortho:para ratio of H{sub 3}{sup +} in these clouds is inconsistent with the temperature derived from the excitation of H{sub 2}, the dominant species in these clouds. In an effort to understand this discrepancy, we have embarked on an experimental program to measure the nuclear spin dependence of the dissociative electron recombination rate of H{sub 3}{sup +} using the CRYRING and TSR ion storage rings. We have also performed the first measurements of the reaction H{sub 3}{sup +}+H{sub 2}→H{sub 2}+H{sub 3}{sup +} below room temperature. This reaction is likely the most common bimolecular reaction in the universe, and plays an important role in interconverting ortho- and para-H{sub 3}{sup +}. Finally, we have constructed a steady-state chemical model for diffuse clouds, which takes into account the spin-dependence of the formation of H{sub 3}{sup +}, its electron recombination, and its reaction with H{sub 2}. We find that the ortho:para ratio of H{sub 3}{sup +} in diffuse clouds is likely governed by a competition between dissociative recombination and thermalization by reactive collisions.

  4. In vitro cell culture, platelet adhesion tests and in vivo implant tests of plasma-polymerized para-xylene films

    Chou, Chia-Man; Yeh, Chou-Ming; Chung, Chi-Jen; He, Ju-Liang

    2013-01-01

    Plasma-polymerized para-xylene (PPX) was developed in a previous study by adjusting the process parameters: pulse frequency of the power supply (ω p ) and para-xylene monomer flow rate (f p ). All the obtained PPX films exhibit an amorphous structure and present hydrophobicity (water contact angle ranging from 98.5° to 121.1°), higher film growth rate and good fibroblast cell proliferation. In this study, in vitro tests (fibroblast cell compatibility and platelet adhesion) and an in vivo animal study were performed by using PPX deposited industrial-grade silicone sheets (IGS) and compared with medical-grade silicone ones (MS), which were commonly manufactured into catheters or drainage tubes in clinical use. The results reveal that PPX deposited at high ω p or high f p , in comparison with MS, exhibit better cell proliferation and clearly shows less cell adhesion regardless of ω p and f p . PPX also exhibit a comparatively lower level of platelet adhesion than MS. In the animal study, PPX-coated IGS result in similar local tissue responses at 3, 7 and 28 days (short-term) and 84 days (long-term) after subcutaneous implantation the abdominal wall of rodents compared with respective responses to MS. These results suggest that PPX-coated industrial-grade silicone is one alternative to high cost medical-grade silicone.

  5. In vitro cell culture, platelet adhesion tests and in vivo implant tests of plasma-polymerized para-xylene films

    Chou, Chia-Man [Department of Surgery, Taichung Veterans General Hospital, Taiwan, ROC (China); National Yang-Ming University, Taipei, Taiwan, ROC (China); Yeh, Chou-Ming, E-mail: cmchou4301@gmail.com [Taichung Hospital, Department of Health, Executive Yuan, Taiwan, ROC (China); Chung, Chi-Jen [Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology, Taiwan, ROC (China); He, Ju-Liang [Department of Materials Science and Engineering, Feng Chia University, Taiwan, ROC (China)

    2013-09-01

    Plasma-polymerized para-xylene (PPX) was developed in a previous study by adjusting the process parameters: pulse frequency of the power supply (ω{sub p}) and para-xylene monomer flow rate (f{sub p}). All the obtained PPX films exhibit an amorphous structure and present hydrophobicity (water contact angle ranging from 98.5° to 121.1°), higher film growth rate and good fibroblast cell proliferation. In this study, in vitro tests (fibroblast cell compatibility and platelet adhesion) and an in vivo animal study were performed by using PPX deposited industrial-grade silicone sheets (IGS) and compared with medical-grade silicone ones (MS), which were commonly manufactured into catheters or drainage tubes in clinical use. The results reveal that PPX deposited at high ω{sub p} or high f{sub p}, in comparison with MS, exhibit better cell proliferation and clearly shows less cell adhesion regardless of ω{sub p} and f{sub p}. PPX also exhibit a comparatively lower level of platelet adhesion than MS. In the animal study, PPX-coated IGS result in similar local tissue responses at 3, 7 and 28 days (short-term) and 84 days (long-term) after subcutaneous implantation the abdominal wall of rodents compared with respective responses to MS. These results suggest that PPX-coated industrial-grade silicone is one alternative to high cost medical-grade silicone.

  6. Estudo da microestrutura formada no processo de soldagem por atrito em aço C-Mn com pino consumível Microstructural evaluation of a C-Mn steel welded by the friction hidro-pillar process

    Cleber Rodrigo de Lima Lessa

    2011-03-01

    Full Text Available A soldagem por arco elétrico é a técnica mais empregada para reparar estruturas de grande porte, mas apresenta desvantagens associadas à solidificação do metal de solda. Então a utilização de processos de solda por atrito, especificamente o processo FHPP (Friction Hydro Pillar Processing que consiste na utilização de pinos para reparo por atrito, apresenta vantagens por ser um processo realizado no estado sólido. Menores temperaturas estão envolvidas e não existe influência do ambiente externo, minimizando os problemas nos reparos estruturais. Este trabalho teve como objetivo observar a variação dos parâmetros do processo e os efeitos desses na microestrutura e qualidade do reparo. O estudo comparou diferentes forças axiais nos reparos com aço C-Mn através de metalografias e perfis de microdureza. Uma força axial maior resultou em um menor tempo de processo, em uma microestrutura mais homogênea e evitou os defeitos "falta de adesão" na zona de ligação e "cisalhamento a quente" do pino.The arc welding it is the most used technique to repair large structures, however, has disadvantages that result from the solidification of the weld metal. So the use of friction welding, specifically the FHPP (friction hydro pillar processing process that consists on using plugs for friction repair, presents advantages because it is a process that is carried out on the solid state. Lower temperatures are involved and do not have the influence of the external environment, minimizing the problems on structure repairs. This work has the objective of observe the process parameters variation and their effects on microstructure and on the quality of the repair. The study compared different axial forces on repairs whit C-Mn steel through of metallographic and microhardness profiles. A higher axial force results in less time of process, in a more homogeneous microstructure, and avoided the defects "noncompliance" in the bounding zone and "hot

  7. Plasma rico em plaquetas para reparação de falhas ósseas em cães Platelet-rich plasma for canine bone restoration

    Anna Laeticia Trindade Barbosa

    2008-08-01

    Full Text Available As plaquetas chegam rapidamente ao local da ferida e liberam múltiplos fatores de crescimento (FC e citocinas que contribuem para a reparação óssea e aumentam a vascularização local. O Plasma Rico em Plaquetas (PRP concentra as plaquetas e os FC liberados por elas, aceleram a formação óssea e melhora a qualidade do trabeculado. Este trabalho apresenta um protocolo para confecção de PRP e demonstra alguns aspectos da sua utilização na reparação óssea de cães. O protocolo foi desenvolvido a partir de sangue coletado por punção jugular em três cães adultos, pesando em média 20kg. Para avaliação da aplicação clínica e dos aspectos da reparação óssea, foram criadas duas falhas mediais no terço proximal de cada tíbia. Assim, a falha 1 não foi preenchida, constituindo o controle, a falha 2 foi preenchida com 3mg de enxerto ósseo autógeno da crista da tíbia, a falha 3 com gel de plaquetas (PRP e falha a número 4 com a associação PRP e 3mg de enxerto ósseo autógeno. O protocolo laboratorial proposto mostrou-se de fácil execução e de baixo custo e possibilitou a concentração adequada de plaquetas no PRP final, cujo número foi dependente da contagem inicial no sangue total de cada animal. A comparação da radiopacidade na região da falha, em todos os tratamentos, e ao longo do tempo demonstrou que o PRP associado ao enxerto determinou maior precocidade e uniformidade de radiopacidade, quando comparado à falha preenchida pelo PRP e ao enxerto usados isoladamente, e sendo que ambos determinam melhores resultados de preenchimento que a falha mantida sem tratamento.The platelets arrive quickly at the injury site and release several growth factors (GF and citokines that contribute to bone repair and increasing local vascularization. The Platelet-rich Plasma (PRP concentrates the platelets and their growth factors, increasing the rate of bone formation and better quality of trabecular bone. This research presents

  8. 3D modeling of material flow and temperature in Friction Stir Welding Modelagem 3D do fluxo de material e da temperatura na soldagem "Friction Stir"

    Diego Santiago

    2009-09-01

    Full Text Available The process of Friction Stir Welding (FSW is a welding method developed by the "The Welding Institute" (TWI of England in 1991. The welding equipment consists of a tool that rotates and progresses along the joint of two restrained sheets. The joint is produced by frictional heating which causes the softening of both components into a viscous-plastic condition and also by the resultant flow between the sheets to be joined. Numerical Modeling of the process can provide realistic prediction of the main variables of the process, reducing the number of experimental tests, thus accelerating the design processes while reducing costs and optimizing the involved technological variables. In this study the friction stir welding process is modeled using a general purpose finite element based program, reproducing the material thermal map and the corresponding mass flow. Numerical thermal results are compared against experimental thermographic maps and numerical material flow results are compared with material flow visualization techniques, with acceptable concordance.O processo denominado "Friction Stir Welding" (FSW é um método de soldagem desenvolvido pelo "The Welding Institute" (TWI na Inglaterra em 1991. O equipamento de soldagem consiste de uma ferramenta que gira e avança ao longo da interface entre duas chapas fixas. A junção é produzida pelo calor gerado por fricção o qual causa o amolecimento de ambos os componentes atingindo uma condição visco-plástica e também pelo escoamento resultante entre as laminas a ser unidas. A modelagem numérica do processo pode fornecer uma predição real das principais variáveis do processo, reduzindo o número de testes experimentais, acelerando, portanto os processos de projeto ao mesmo tempo em que reduz custos e permite a otimização das variáveis tecnológicas envolvidas. Neste trabalho, o processo de soldagem por fricção é modelado empregando um programa de propósito geral baseado no m

  9. Efeito do Arrefecimento Causado pelo Fluido Durante a Soldagem em Operação em Tubulações com Espessura de Parede de 6 e 11 mm

    Jefferson Pinto Soares

    Full Text Available Resumo Este trabalho compara a influência do arrefecimento causado por um fluído em circulação e em contato com a parede interna de uma tubulação, que caracteriza a soldagem em operação. Foram avaliadas duas espessuras de parede do tubo e duas temperaturas do fluido interno. A soldagem foi realizada na ligação de conexões de aço ASTM A105 a um tubo API 5L Gr X60 com espessura de 11 mm e de 6 mm, utilizando os processos TIG (GTAW e eletrodo revestido (SMAW. A circulação do fluido foi feita com água potável em duas faixas de temperatura, de 6 a 10 °C e 18 a 36 °C. Durante a soldagem, a temperatura interna do tubo e a taxa de resfriamento foram monitoradas. Foram preparadas quatro juntas soldadas, avaliadas por ensaios não destrutivos (inspeção visual, líquido penetrante, partículas magnéticas e ultrassom, ensaios destrutivos (tração, dobramento, impacto, fratura e dureza e análise macrográfica e micrográfica. Os resultados mostram que, com os procedimentos adotados, não é necessária a adoção de cuidados especiais quanto à possibilidade de perfuração e vazamento de fluido durante a soldagem em operação. Houve evidencias que o efeito do arrefecimento do fluido no interior do tubo foi mais significativo que a espessura da parede do tubo no aumento da taxa de resfriamento. Ainda, a temperatura do fluido em circulação no tubo exerceu papel secundário no aumento da taxa de resfriamento e na redução da temperatura máxima na parede interna do tubo. O arrefecimento causado pelo fluido provocou aumento na dureza da ZF e ZTA, reduziu o alongamento no ensaio de tração, porém ainda em valores adequados. Estes comportamentos foram mais observados no tubo de menor espessura, de 6 mm. Foi possível, pelos resultados dos ensaios não destrutivos e ensaios mecânicos obtidos, qualificar os procedimentos de soldagem, com base nas normas especializadas neste processo.

  10. Processamento de Ligas de Níquel com Técnica de Manufatura Aditiva Utilizando Plasma por Arco Transferido

    Eduardo André Alberti

    2015-06-01

    Full Text Available ResumoA manufatura aditiva é um processo utilizado para a construção e reparos de peças que possuem geometria complexa ou que necessitem de gradiente de propriedades. Nessa técnica múltiplas camadas são depositadas para a construção da geometria do componente. O sucesso desse procedimento depende de fatores como a técnica de deposição, parâmetros, liga a ser depositada e condições da deposição, como temperatura e atmosfera protetora. Neste estudo, o potencial da técnica de Plasma por arco transferido para manufatura aditiva foi avaliado produzindo “paredes finas”, construídas a partir da sobreposição de cordões. Foram utilizadas duas ligas a base de níquel, uma endurecida por precipitação e outra endurecida por solução sólida. Durante os trabalhos, foram selecionados os parâmetros de processamentos, incluindo a avaliação do efeito do pré-aquecimento a 300°C. Resultados mostraram que a composição química da liga influencia a geometria da parede construída assim como a utilização de pré-aquecimento. Estruturas de solidificação exibindo dendritas refinadas com crescimento epitaxial entre camadas são identificadas. Entretanto, as características da liga determinam o perfil de dureza ao longo da seção transversal, sendo a liga endurecida por precipitação influenciada pelos ciclos térmicos de deposição e a liga endurecida por solução sólida pela diluição com o substrato. Em qualquer dos casos é recomendado a aplicação de tratamento térmico pós-soldagem para uniformização das propriedades.

  11. Parameters optimization for friction spot welding of AZ31 magnesium alloy by Taguchi method Otimização dos parâmetros de soldagem por fricção por ponto da liga de magnésio AZ31 pelo método de Taguchi

    Leonardo Contri Campanelli

    2012-03-01

    Full Text Available Friction spot welding (FSpW is a solid state welding process suitable for producing spot-like joints, especially in lightweight materials, which are particularly interesting due to the weight saving potential. The plunging of an especially designed non-consumable and rotating tool creates a connection between overlapped sheets through frictional heat and plastic deformation. Minimum material loss is observed, and therefore a fully consolidated joint with flat surface (no keyhole is obtained. In the current study, the effect of FSpW parameters, such as rotational speed, plunge depth and dwell time, on lap shear strength of AZ31 magnesium alloy joints was investigated. The optimization of input process parameters was carried out through Taguchi approach of DOE. Analysis of variance was applied to determine the individual importance of each parameter. Main effect plots were used to indicate the best levels for maximizing lap shear strength. The results show that tool plunge depth has the higher effect on the weld strength, followed by rotational speed and dwell time.A soldagem por fricção por ponto (FSpW é um processo de soldagem no estado sólido adequado para a produção de juntas pontuais, especialmente em materiais leves, que são particularmente interessantes devido ao potencial de redução de peso. A penetração de uma ferramenta não-consumível e rotacional especialmente desenvolvida cria uma junção entre as placas sobrepostas através de calor por fricção e deformação plástica. A perda de material é mínima, obtendo-se, portanto, uma junta totalmente consolidada com superfície plana (sem furo. Neste trabalho, investigou-se o efeito dos parâmetros do FSpW, tais como velocidade de rotação, profundidade de penetração e tempo de residência, na resistência ao cisalhamento das juntas de liga de magnésio AZ31. A otimização dos parâmetros de entrada do processo foi realizada através do método de Taguchi de DOE. A an

  12. Caracterização e avaliação da resistência à corrosão na soldagem de tubulação de aço inoxidável duplex UNS S31803 pelo processo a arco submerso Characterization and evaluation of corrosion resistance of welded joint of duplex stainless steel pipe UNS S31803 by submerged arc process

    Juan Manuel Pardal

    2011-12-01

    Full Text Available O presente trabalho apresenta os resultados da caracterização e avaliação da resistência à corrosão de uma junta soldada correspondente a uma tubulação de aço inoxidável duplex (AID UNS S31803 de 35 mm de espessura de parede soldada pelos processos de soldagem TIG (GTAW na raiz e arco submerso (SAW no enchimento e acabamento. Foram empregados como consumíveis de soldagem metais de adição de liga 25Cr-9Ni-4Mo (% em peso. Os resultados da caracterização das propriedades mecânicas, composição química e resistência à corrosão em diversas regiões da junta soldada foram comparados com os obtidos para o metal de base da tubulação, assim como com os valores mínimos exigidos pelas normas de projeto. Os resultados obtidos demonstram claramente a possibilidade da implementação do processo SAW na pré fabricação de tubulações de paredes espessas de AID, tendo em vista os resultados das propriedades analisadas e a grande demanda na construção e montagem de tubulações desta família de aço inoxidáveis na indústria offshore.This work presents the mechanical properties, microstructural and corrosion resistance evaluation of a welded joint of duplex stainless steel (DSS pipe with 35 mm wall thickness. The joint was welded by gas tungsten arc welding (GTAW process in the root passes and submerged arc welding (SAW in the filling and cap passes using filler metals with composition 25Cr-9Ni-4Mo (%wt.. The results of mechanical properties, chemical composition and corrosion resistance characterization in different regions of the welded joint were compared to the base metal and to the specifications required by the standards applied in the project. The main focus of this work was to show the successful utilization of SAW process in the welding of thick wall pipes of DSS. The application of high productivity process such as SAW has a crescent demand in offshore industry.

  13. Application of NIR - CRDS for state selective study of recombination of para and ortho H3+ ions with electrons in low temperature plasma

    Varju, J.; Roučka, Š.; Kotrík, T.; Plašil, R.; Glosík, J.

    2010-05-01

    We present a study of H3+ recombination performed at 77 K on the two lowest rotational levels of this ion, which belong to its two different nuclear spin states of the studied ion. A near infrared cavity ring-down spectrometer (~1381 nm, CRDS arrangement) has been used to obtain the time evolution of concentration of both states. From the overall ion density decay during the afterglow we obtained the binary recombination rate coefficient αbin (77 K) = 1.2×10-7 cm3s-1. We have also observed ternary helium assisted recombination of both para and ortho H3+. The process is very slow (at 77 K) and the obtained ternary recombination rate coefficient is in contradiction with the theoretical prediction. It is the first time that the binary and ternary H3+ recombination rate coefficient was measured at a known population of para and ortho H3+ ions in decaying plasma.

  14. Application of NIR - CRDS for state selective study of recombination of para and ortho H3+ ions with electrons in low temperature plasma

    Varju, J; Roucka, S; KotrIk, T; Plasil, R; Glosik, J

    2010-01-01

    We present a study of H 3 + recombination performed at 77 K on the two lowest rotational levels of this ion, which belong to its two different nuclear spin states of the studied ion. A near infrared cavity ring-down spectrometer (∼1381 nm, CRDS arrangement) has been used to obtain the time evolution of concentration of both states. From the overall ion density decay during the afterglow we obtained the binary recombination rate coefficient α bin (77 K) = 1.2x10 -7 cm 3 s -1 . We have also observed ternary helium assisted recombination of both para and ortho H 3 + . The process is very slow (at 77 K) and the obtained ternary recombination rate coefficient is in contradiction with the theoretical prediction. It is the first time that the binary and ternary H 3 + recombination rate coefficient was measured at a known population of para and ortho H 3 + ions in decaying plasma.

  15. IMPLEMENTACIÓN DE UNA METODOLOGÍA PARA LA SEPARACIÓN DE PROTEOMAS DE PLASMA HUMANO MEDIANTE ELECTROFORESIS BIDIMENSIONAL

    Ruth Andrea Rodríguez

    2015-09-01

    Full Text Available El análisis proteómico en derivados sanguíneos es una importante herramienta en el descubrimiento de biomarcadores para el diagnóstico de enfermedades, aunque su caracterización exhibe desafíos relacionados con el amplio rango dinámico de las proteínas. En este trabajo se implementaron las condiciones para la separación de proteomas de plasma sanguíneo por electroforesis bidimensional. En muestras de plasma de infante y adulto se evaluaron dos sistemas de pretratamiento de la muestra para reducir el rango dinámico de las proteínas: inmunodepleción de proteínas abundantes y enriquecimiento de proteínas de baja abundancia. Los proteomas se separaron por electroforesis bidimensional y las imágenes se analizaron con el programa Melanie 7.0. Se encontró que ambos métodos de pretratamiento fueron reproducibles y permitieron ver las diferencias en los proteomas de infante y adulto, como muestran los análisis de componentes principales y de clasificación jerárquica tipo heatmap. El porcentaje de recuperación de proteínas fue mayor con la inmunodepleción en comparación con el enriquecimiento proteico. Estos resultados permitieron concluir que con la inmunodepleción, se tiene mayor control de las proteínas eliminadas y por tanto menor pérdida de información, lo que permite su aplicación en estudios exploratorios para la identificación de potenciales biomarcadores de enfermedad.

  16. Efeito do formato de onda e gás de proteção sobre a taxa de fusão e geometria do cordão na soldagem MIG/MAG-PV Effect of waveform and shielding gas on melting rate and bead geometry for MIG/MAG-PV

    Alexandre Saldanha do Nascimento

    2012-03-01

    Full Text Available Dada a importância do uso da polaridade variável na soldagem MIG/MAG (MIG/MAG-PV, com grande potencial para a aplicação de revestimento e para a soldagem de passe de raiz, �� fundamental investigar os efeitos de parâmetros do processo na formação do cordão e na taxa de fusão do arame-eletrodo. Esta última em especial, dada a maior taxa de fusão obtida pelo período de polaridade negativa. Desta forma, procurou-se avaliar o efeito de dois formatos de onda investigados anteriormente que possuem pausa de corrente antes e após o pulso principal do período de polaridade positiva, haja vista que estas condições se mostraram as mais estáveis. Investigou-se também o efeito do tipo de gás de proteção utilizado sobre as características geométricas do cordão de solda (representadas pela largura, penetração e reforço e taxas de fusão e deposição e o rendimento. As soldagens foram executadas em simples deposição sobre chapas de aço SAE 1020 pelo processo MIG/MAG-PV com 30 e 50% de porcentagem de tempo com eletrodo em polaridade negativa. Os gases de proteção utilizados foram Ar+2%O2, Ar+5%O2, Ar+8%CO2 e Ar+15%CO2. Procurou-se manter o mesmo comprimento de arco em todos os testes, por meio da variação da velocidade de alimentação de arame. Além disto, foi mantida constante a relação velocidade de alimentação de arame pela velocidade de soldagem, com o objetivo de tentar manter o volume de metal depositado constante para comparação. Pode-se concluir que o melhor entendimento do comportamento da geometria em relação aos parâmetros e consumíveis utilizados auxiliará para garantir o perfil do cordão desejado de acordo com a aplicação. Aliado a isto, a análise da taxa de fusão do processo possibilita selecionar com mais coerência os parâmetros e consumíveis utilizados que forneçam menores perdas de material e maior produtividade.Due to the importance of variable polarity in MIG/MAG welding (MIG

  17. Influence of laser design parameters on the hydrodynamics of microfusion plasmas; Influencia de los parametros basicos del laser sobre la hidrodinamica de plasmas para microfusion

    Sanmartin, J A; Barrero, A

    1976-07-01

    The quasi neutral, one dimensional motion generated in a cold, infinite, uniform plasma of density n{sub 0}, by the absorption, In a given plane, of a linear pulse of energy per unit time and area {phi} - {phi}{sub 0}t/{tau}, 0< t {<=} {tau}, is considered; the analysis allows for thermal conduction and viscosity of ions and electrons, their energy exchange, and an electron thermal flux limiter. The motion is found to be self similar and governed by single non dimensional parameter {alpha} similar{sub t}o(n{sup 2}{sub 0} {tau}/{phi}{sub 0}){sup 2}/3. Detailed asymptotic results are obtained for both {alpha}<<1and {alpha}>>1; the general (behaviour of the solution for arbitrary {alpha} is discussed. The analysis can be easily extended to the case of a plasma initially occupying a half-space, and throws light on the hydrodynamics of laser fusion plasmas. (Author) 51 refs.

  18. Excitation of a plasma by high frequencies for illumination purposes; Excitacion de un plasma por altas frecuencias para propositos de iluminacion

    Valdivia B, R

    2003-07-01

    The power electronics plays a very important paper so much in the national as international industrial development. For that reason, many of the works are focused in the one analysis and amplification of this area with the purpose of finding improvements in the existent systems and always looking for oneself end: the energy saving. Moreover, in the last years has occurred great interest to other very important area given their properties of energy profit, novelty and mainly their wide range of applications. This area is the study and use of the plasma. Many institutions with international recognition already invest and they develop systems in these two big areas of the technology among those that is the National Institute of Nuclear Research (INlN) with some laboratories dedicated to the work of the plasma, one of them the Laboratory of Thermal Plasma Applications (LAPT). The conjugation of both areas was analysed and developed in the present work with the one purpose of designing a system to generate thermal plasma and to give him one or but applications like it is to produce a luminous source as like to degrade organic gases as the Methane or Acetylene. This was developed by means of a resonant inverter with the help of MOSFET IRFK2D450 transistors and a load L C in a serial-parallel configuration with the purpose to profit their condition of resonance to have the maximum transfer of energy to the plasma. For to have a best profit of the energy it was realized an analysis of design for to oblige to the transistors to commute in zero voltage (ZVS) and to avoid then lost of power of C A. (Author)

  19. Caracterização de Uma Junta Dissimilar entre Aço Carbono e Inconel 625 Obtida por Soldagem por Explosão

    Rodrigo Andrade Ribeiro

    Full Text Available Resumo Neste trabalho é caracterizada uma junta dissimilar entre aço carbono e inconel 625 obtida pela soldagem por explosão. A caracterização metalográfica foi feita com uso de diferentes ataques químicos e observação microestrutural do metal de base (MB, a interface e o revestimento de inconel 625 por meio de microscopia ótica (MO, microscopia eletrônica de varredura (MEV e espectroscopia de energia dispersa (EDS. Ensaios de microdureza foram realizados em todas as regiões. Os resultados mostram forte deformação dos grãos na proximidade da interface, tanto do lado do MB quanto do lado do inconel, tendo sido verificado significativo aumento da dureza. Na interface, ocorre o aparecimento de zonas localmente fundidas devido à dissipação de energia no impacto durante a explosão. Estas zonas apresentam microestrutura provavelmente martensítica. O trabalho conclui que o processo atinge os níveis de qualidade e produtividade característicos do segmento offshore.

  20. Analise da adaptação marginal de proteses fixas implanto-suportadas em liga de titanio, fundidas em monobloco ou submetidas a soldagem laser e eletroerosão atraves do assentamento passivo

    Tatiana Bernardon Peixoto Silva

    2001-01-01

    Resumo: A proposta deste trabalho foi avaliar o desadaptação marginal de infra-estruturas de próteses fixas implanto-suportadas fundidas em monobloco e submetidas à soldagem laser, antes e após a eletroerosão através da análise do assentaIÍlento passivo. Vinte infta-estruturas foram confeccionadas a partir de um modelo mestre metálico com cinco implantes fixados na região inter-forâmes paralelos entre si, e fundidas em titânio comercialmente puro - Ti c. p. (Rematitan - Dentaurum - Pforzhein ...

  1. Efeito do desajuste marginal, tipo de soldagem e material do parafuso sobre a força de destorque de parafusos protéticos e tensões induzidas aos pilares

    Sabrina Alessandra Rodrigues

    2012-01-01

    Resumo: O objetivo neste estudo foi analisar as tensões induzidas aos análogos de pilares protéticos, utilizando-se strain gauges; e avaliar a força de destorque de parafusos protéticos (ouro e titânio) em infraestruturas fundidas em titânio comercialmente puro (Ti cp), antes e após os procedimentos de soldagem laser e TIG (tungsten inert gas). Foram confeccionadas vinte infraestruturas fundidas em titânio comercialmente puro (Ti cp), simulando uma prótese fixa de três elementos; vinte modelo...

  2. Utilização de plasmas em pressão atmosférica para modificação de polímeros biocompatíveis

    Lopes, Bruno Bellotti [UNESP

    2013-01-01

    Neste trabalho foi desenvolvido um equipamento para produção de plasmas em pressão atmosférica. Empregando esse sistema, o polímero PLDLA (poli(L-Co,L ácido lático)) e sua blenda com o tri(carbonato de metileno) (poli(L-Co-D,L-Co TMC)) foram hidrofilizados em diferentes condições de tempo e potência de plasma. Seus ângulos de contato foram investigados anteriormente e após cada exposição ao plasma para se avaliar o efeito do tratamento. Espectroscopia de emissão óptica foi empregada para se c...

  3. The influence of screw type, alloy and cylinder position on the marginal fit of implant frameworks before and after laser welding Influência do tipo de parafuso, liga e da posição do cilindro na adaptação marginal das infra-estruturas sob implantes antes e após a soldagem a laser

    Daniela Castilio

    2006-04-01

    ânio. OBJETIVOS: Avaliar a influência do tipo de parafuso, liga e posição do cilindro na adaptação marginal de infra-estruturas sobre implante antes e após a soldagem a laser. MÉTODOS: Após os abutments do tipo Estheticone serem aparafusados nos implantes, trinta cilindros protéticos de plástico foram montados e encerados com 15 barras cilíndricas. Cada espécime possuía três componentes protéticos interconectados. Cinco espécimes foram fundidos em monobloco com liga de titânio e liga de cobalto-crômio. Em cada espécime, os testes foram conduzidos com parafusos hexagonais de titânio e com parafusos de ouro com fenda, separadamente, num total de 30 parafusos testados. As medidas nas interfaces foram feitas com microscópio óptico com 5mm de precisão. Após o seccionamento, os espécimes foram soldados a laser e novas medidas obtidas. Os dados foram submetidos para análise com os testes ANOVA a quatro critérios e Tukey para comparações múltiplas (alfa=0,05. RESULTADOS: Os parafusos com fenda e hexágono não apresentaram diferenças significantes independente da adaptação dos cilindros fundidos em titânio, tanto em monobloco como após a soldagem a laser. Quando os parafusos com hexágono e fenda foram testados nos espécimes de cobalto-crômio, diferenças estatisticamente significantes foram encontradas na condição monobloco, com os parafusos fendidos apresentando melhor adaptação (24,13µm do que os com hexágono (27,93 µm. Além disso, nenhuma diferença significante foi encontrada após a soldagem a laser. CONCLUSÕES: 1 O uso de diferentes ligas metálicas exerce influência nos resultados, 2 Os parafusos com hexágono e fenda somente possuem o papel de fixar a prótese, e não melhoram a adaptação dos cilindros e 3 a posição do cilindro não afetou os valores de adaptação marginal.

  4. Construcción y caracterización de un nuevo nebulizador múltiple para técnicas analíticas basadas en plasma (ICP-OES, ICP-MS y MP-AES).

    Lúñez Fernández, Claudia

    2016-01-01

    En la siguiente memoria, se presenta la metodología para la construcción de un nuevo nebulizador múltiple, resultado de una serie de nebulizadores anteriores, los cuales se han ido mejorando para optimizar las características del aerosol generado y con ello los parámetros analíticos de calidad en la espectrometría de emisión atómica con plasma de microondas (MP-AES) y espectrometría de emisión óptica con plasma de acoplamiento inductivo (ICP-OES). Este nuevo nebulizador multiconducto presenta...

  5. Método analítico para a determinação de meloxicam em plasma humano por cromatografia líquida de alta eficiência (CLAE Determination of meloxicam in human plasma by HPLC

    Valentina Porta

    2005-06-01

    Full Text Available Desenvolveu-se e validou-se método analítico simples, rápido e específico para quantificação de meloxicam (inibidor da COX-2 em plasma humano através da cromatografia líquida de alta eficiência, para aplicação em estudos de bioequivalência. Piroxicam foi utilizado como padrão interno. Empregou-se cromatografia em fase reversa com coluna modelo Synergi RP-MAX (150 x 4,6 mm, à temperatura de 30 ºC e fase móvel constituída por mistura de acetonitrila e tampão fosfato 0,025 mol/L pH 4,5 (40:60, v/v, a um fluxo de 1,0 mL/min. Os analitos foram detectados por UV a 364 nm. As amostras de plasma foram acidificadas com ácido clorídrico 1 mol/L, extraídas utilizando-se éter terc-butil metílico e, após filtração e secagem, o resíduo foi reconstituído em 250 mL de fase móvel para injeção em CLAE. Os tempos de retenção para meloxicam (padrão e piroxicam (padrão interno foram 3,35 e 4,19 minutos, respectivamente. Este método apresentou linearidade na faixa de concentração entre 50-4000 ng/mL (R² = 0,9995, com limite de quantificação inferior de 50 ng/mL e exatidão de 114%. O método analítico desenvolvido neste trabalho demonstrou especificidade, linearidade, precisão e exatidão adequadas, permitindo sua aplicação em ensaios de bioequivalência.A simple, rapid and specific high-performance liquid cromatographic (HPLC method was developed and validated to estimate meloxicam (COX-2 inhibitor levels in human plasma. Piroxicam was used as internal standard. Reversed phase chromatography was conducted using a Synergi RP-MAX (150 x 4.6 mm column at 30 ºC and a mobile phase of acetonitrile and 0.025 mol/L pH 4,5 phosphate buffer (40:60, v/v, at a flow rate of 1mL/min. Analytes were detected at 364 nm. Plasma samples were acidified with 1 mol/L hydrochloric acid and extracted with tert-butyl methyl ether, evaporated to dryness, reconstituted in 250 mL of mobile phase and injected in the column. The retention time of

  6. Application of NIR - CRDS for state selective study of recombination of para and ortho H{sub 3}{sup +} ions with electrons in low temperature plasma

    Varju, J; Roucka, S; KotrIk, T; Plasil, R; Glosik, J, E-mail: Juraj.Glosik@mff.cuni.c [Charles University, Faculty of Mathematics and Physics, Department of Surface and Plasma Science, V Holesovickach 2, Prague 8 (Czech Republic)

    2010-05-01

    We present a study of H{sub 3}{sup +} recombination performed at 77 K on the two lowest rotational levels of this ion, which belong to its two different nuclear spin states of the studied ion. A near infrared cavity ring-down spectrometer ({approx}1381 nm, CRDS arrangement) has been used to obtain the time evolution of concentration of both states. From the overall ion density decay during the afterglow we obtained the binary recombination rate coefficient {alpha}{sub bin} (77 K) = 1.2x10{sup -7} cm{sup 3}s{sup -1}. We have also observed ternary helium assisted recombination of both para and ortho H{sub 3}{sup +}. The process is very slow (at 77 K) and the obtained ternary recombination rate coefficient is in contradiction with the theoretical prediction. It is the first time that the binary and ternary H{sub 3}{sup +} recombination rate coefficient was measured at a known population of para and ortho H{sub 3}{sup +} ions in decaying plasma.

  7. Effects of plasma polymerized para-xylene intermediate layers on characteristics of flexible organic light emitting diodes fabricated on polyethylene terephthalate substrates

    Sohn, Sunyoung; Kim, Kyuhyung; Kho, Samil; Jung, Donggeun; Boo, Jin-hyo

    2008-01-01

    Characteristics of flexible organic light emitting diodes (FOLEDs) with the plasma polymerized para-xylene (PPpX) intermediate layer were investigated. For the purpose of reducing moisture permeation through plastic substrates, a PPpX intermediate layer was inserted between FOLEDs and the plastic substrates. As the concentration of C-H bonding in the PPpX film deposited at 25 deg. C was increased, PPpX films showed increased transmittance. Surface morphologies of polyethylene terephthalate (PET) covered with the PPpX intermediate layer were improved compared to PET without PPpX on it. Due to the highly cross-linked network structure in the plasma polymer film, water vapor permeability of PET substrates with the PPpX intermediate layer of 75 nm was decreased compared to PET substrates without PPpX on it. FOLEDs with the PPpX intermediate layer showed improved optical and electrical characteristics as well as lifetimes than FOLEDs without the PPpX intermediate layer

  8. Supersonic flow with shock waves. Monte-Carlo calculations for low density plasma. I; Flujo supersonico de un plasma con ondas de choque, un metodo de montecarlo para plasmas de baja densidad, I.

    Almenara, E; Hidalgo, M; Saviron, J M

    1980-07-01

    This Report gives preliminary information about a Monte Carlo procedure to simulate supersonic flow past a body of a low density plasma in the transition regime. A computer program has been written for a UNIVAC 1108 machine to account for a plasma composed by neutral molecules and positive and negative ions. Different and rather general body geometries can be analyzed. Special attention is played to tho detached shock waves growth In front of the body. (Author) 30 refs.

  9. Protocolo para obtenção do plasma rico em plaquetas de cães

    Ferreira, Vanessa Borges costa [UNESP

    2012-01-01

    Biotechnology as the platelet-rich plasma (PRP) have been widely used in tissue repair, aiming to accelerate the healing of wounds. The potencial of PRP to reduce the recovery time of injuries depends on the concentration of platelets, its function and their growth factors. The lack of protocols for obtaining PRP in dogs, combined with variations of the same, hinders the use of biotech. The aim of this study was to test three different protocols for obtaining PRP and verify effectiveness in d...

  10. The fitness of copings constructed over UCLA abutments and the implant, constructed by different techniques: casting and casting with laser welding Adaptação de copings de ritânio ao implante, construídos sobre pilares UCLA por duas técnicas: fundição e fundição com soldagem de bordo laser

    Elza Maria Valadares da Costa

    2004-12-01

    adaptação passiva de sua estrutura protética é um fator relevante para o sucesso deste trabalho. Um estudo comparativo foi feito entre dois métodos de confecção de prótese unitária suportada por implante. Para tanto incluímos no centro de um bloco de resina um implante rosqueado de 3.75mm de diâmetro por 10.0mm de comprimento (3i Implant innovations, Brasil e sobre este parafusamos com torque de 20N.cm 15 pilares UCLA torneados anti-rotacionais (137CNB, Conexão Sistemas de Próteses, Brasil sem qualquer procedimento laboratorial (grupo controle - GC. A partir de um molde de silicone, 15 componentes tipo UCLA calcináveis (56CNB, Conexão Sistemas de Próteses, Brasil foi parafusado (20N.cm ao implante e receberam enceramentos padrão (face vestibular plana os quais foram fundidos em titânio (grupo fundição - GF. 15 componentes, tipo UCLA torneados em titânio (137CNB, Conexão, Sistemas de Próteses, Brasil receberam o mesmo enceramento padrão e estes copings foram fundidos em titânio separados e soldados a laser aos respectivos pilares em seu bordo (grupo soldagem a laser- GSL. A adaptação marginal foi observada na interface implante/componente, sob microscópio de medição, no eixo y, em 4 pontos de referência na vestibular, lingual, mesial e distal previamente marcados no bloco. As médias aritméticas foram obtidas e uma análise dos dados foi feita para determinar o teste estatístico mais apropriado. Os dados estatísticos descritivos (µm para Controle (média ± desvio padrão:13.50 ± 21.80; mediana 0.00, for Fundição (36.20 ± 12.60; 37.00, para Laser (10.50 ± 12.90; 3.00 foram submetidos ao Kruskal-Wallis ANOVA, alfa = 5%. Resultados: Os testes mostraram que os valores médios de distorção diferem estatisticamente (kw = 17.40; df =2; p = 0.001<0.05. O teste Dunn's (5% mostra diferença entre Fundição e os outros dois grupos. Conclusão: No eixo y, os menores valores de distorção foram obtidos pelo grupo soldagem a laser de bordo

  11. Validación de un método de cromatografía líquida para la determinación de rifampicina en plasma humano

    Luis Moreno-Exebio

    Full Text Available Objetivos: Validar un método de cromatografía líquida de alta resolución (HPLC para la determinación de rifampicina (RFP en plasma humano. Materiales y métodos. Se desarrolló un método HPLC para la determinación de RFP en plasma. La separación fue realizada por cromatografía de fase reversa con una columna C18 y una fase móvil compuesta por una mezcla de acetonitrilo y solución amortiguadora de fosfato de potasio monobásico 0,05 M (38:62 v/v a 335 nm. En el cual se empleó como estándar interno rifampicina quinona (RFP-QN. Resultados. Los tiempos de retención de RFP y RFP-QN fueron 7,81 y 12,26 minutos, respectivamente. El ensayo fue lineal de 0,5 a 250 ug/mL Los parámetros evaluados de precisión, exactitud, selectividad, linealidad, recuperación cumplieron con lo establecido en las guías internacionales de validación de métodos bioanalíticos. Conclusiones. El método HPLC desarrollado es simple, específico, sensible, selectivo y lineal para un amplio rango de concentraciones de RFP en plasma

  12. Avaliação de sete protocolos para obtenção de plasma rico em plaquetas na espécie equina Evaluation of seven platelet-rich plasma processing protocols in the equine species

    Roberta Carneiro da Fontoura Pereira

    2013-06-01

    Full Text Available O presente estudo teve por objetivo avaliar a capacidade de concentração plaquetária e sua correlação com os níveis do fator de crescimento TGF-B1, a presença de leucócitos e de hemácias nos diferentes protocolos utilizados na obtenção do plasma rico em plaquetas (PRP de equinos, através do método manual. Dez equinos, sadios, com idade média de 7 anos (±2,39, pesando em média 500kg (±67,1 foram utilizados neste estudo. Os protocolos testados variaram na velocidade e no tempo nas duas centrifugações. As variáveis analisadas nas amostras de PRP foram: concentração de plaquetas, presença de leucócitos e hemácias, e níveis de TGF-β1 quantificados pelo teste ELISA. Os protocolos testados não diferiram na capacidade de concentração de plaquetas e nos níveis de TGF-β1. Entretanto, houve diferença significava entre o protocolo I e os demais por este apresentar maior número de hemácias e leucócitos nas amostras de PRP, sendo por esse motivo considerado um protocolo inadequado para processamento do volume de sangue utilizado. Os demais protocolos podem ser utilizados para obtenção de PRP terapêutico em equinos.PRP is plasma that contains a high numbers of platelets and growth factors in a small volume. The aim of this study was to evaluate seven different protocols to obtain PRP by the manual method according to their capacity to concentrate platelets, leukocyte and erythrocyte contamination and correlation between platelet count and TGF-β1 growth factor levels in PRP samples. Ten healthy horses with a mean age of 7 years (±2.39, weighing on average 500 kg (±67.1 were used in this study. The protocols tested varied according to the speed and time used at the two centrifugations. PRP samples were analyzed regarding platelet concentration, leukocyte and erythrocyte contamination and TGF-β1 levels quantified by ELISA. No significant differences among protocols were observed regarding the ability to concentrate

  13. Soldagem de um aço inoxidável ferrítico com o processo A-TIG Ferritic stainless steel welding with the A-TIG process

    Alessandra Gois Luciano de Azevedo

    2009-03-01

    Full Text Available O processo de soldagem TIG com fluxo (processo A-TIG apresenta como principal vantagem a possibilidade de se obter uma maior penetração do cordão de solda empregando os mesmos parâmetros de soldagem do processo TIG convencional. Diversos estudos mostram a influência dos fluxos ativos sobre as características geométricas das soldas em aços inoxidáveis austeníticos, porém pouco se sabe sobre a influência deste processo nas características geométricas e metalúrgicas de cordões de solda em aços inoxidáveis ferríticos. Neste trabalho são aplicados diferentes tipos de fluxo na soldagem de aço inoxidável ferrítico com o objetivo de verificar possíveis influências no perfil do cordão de solda, no seu aspecto visual, na microestrutura, na dureza da zona fundida e na resistência ao impacto (ensaio Charpy. As soldagens "bead-on-plate" foram realizadas sem metal de adição. Foram utilizados seis tipos de fluxo, sendo um óxido elaborado em laboratório (TiO2 e cinco fluxos comerciais. Os resultados mostraram que a utilização do fluxo permite um aumento na penetração com mudanças significativas no aspecto do cordão de solda. Verificou-se ainda que a microestrutura e a dureza do cordão de solda do aço estudado não foram afetadas pelo tipo de fluxo utilizado, com a microestrutura analisada em microscópio óptico. O aço em estudo mostrou um alto grau de fragilidade à temperatura ambiente.The A-TIG welding process presents as main advantage the possibility of increase in the penetration depth using the same parameters as conventional TIG welding. Many researchers show the influence of the active flux on the weld geometry in austenitic stainless steel, however little it is known of the influence of this process in the weld fillet shape and metallurgic characteristics of the weld fillet in ferritic stainless steel. In this work different types of flux are applied with the objective to verify possible influences on the weld

  14. Análisis de plasmas inducidos por láser con excitación multipulso para el proceso de ablación de areolas de Tuna

    Teresa Flores

    2010-01-01

    Full Text Available Introducción: La técnica de análisis de plasmas inducidos por láser (LIBS, posee importantes ventajas como son que la muestra no requiere preparación previa, puede estar en fase sólida, liquida o gaseosa y tener cualquier forma y dimensión, se requiere una cantidad mínima de material y, finalmente, el análisis se realiza en tiempo real. Estas ventajas, hacen posible el seguimiento en tiempo real de un proceso de ablación láser, incluso para muestras de composición compleja. Para el monitoreo de un proceso industrial, esta herramienta sería más adecuada, si se cuenta con una calibración del equipo y un protocolo particular definido. En el trabajo, se ejemplifica esta posibilidad para el caso de la ablación láser de areolas de Tuna (fruto de el Opuntia ficus-indica. Método: Se realiza el análisis LIBS de muestras de tuna, tanto en las areolas como en la corteza. Para la excitación del plasma se emplea un láser de Nd:YAG en régimen de Q:Switch con tren de pulsos. Con el objeto de asegurar el reconocimiento de las líneas en los espectros LIBS, se realizaron análisis en patrones de composición conocida, estableciéndose un protocolo para la interpretación de los espectros. Resultados: Se logró una clara lectura de la línea de H ubicada en 656.2 nm. Se estableció un protocolo para la interpretación de los espectros, que permitió la identificación de 49 picos característicos. Finalmente, se determina la composición para la corteza y la areola y se lleva a cabo una comparación cualitativa entre éstas. Discusión: Se muestra que la excitación láser en forma de tren de pulsos, entendido este régimen como modalidad particular del Q:Switch, permite la determinación eficiente de elementos, con una adecuada relación señal-ruido. Por otra parte, que es posible determinar diferencias composicionales evidentes entre corteza y la areola, lo cual permite monitorear un proceso de ablación de areolas con láser de manera

  15. Caracterización de un plasma pulsado utilizado para producir recubrimientos de TiN, por medio de espectroscopía óptica de emisión

    Restrepo Parra, Elisabeth

    2001-01-01

    En este trabajo se realiza la caracterización de un plasma pulsado utilizado para la producción de recubrimientos duros de TiN, utilizando técnicas de espectroscopía óptica de emisión. Con el fin de realizar esta caracterización se han calculado la temperatura y la densidad electrónica de dicho plasma. El cálculo de la temperatura electrónica se realiza suponiendo que esta es diferente de la temperatura de excitación de los átomos, esto nos permite modificar el método más convencional, co...

  16. Magnetic spires for the detection of the position of the plasma column in a Tokamak (linear approximation); Espiras magneticas para la deteccion de la posicion de la columna de plasma en un Tokamak (aproximacion lineal)

    Colunga S, S

    1990-07-15

    In this report the simplified analysis of a method to detect the movement of the plasma column of a tokamak in the vertical direction and of the biggest radius is given. The peculiar case of the Tokamak Novillo of the Plasma Physics Laboratory of the ININ is studied. (Author)

  17. Utilização de plasma rico em plaquetas de coelhos com poucos leucócitos e hemácias para a consolidação de ossos

    M.G.M.G. Andrade

    2016-04-01

    Full Text Available Objetivou-se utilizar o plasma rico em plaquetas, obtido por técnica capaz de produzir um produto autólogo, com reduzido número de leucócitos e hemácias, e avaliar, por meio de radiografias, a capacidade de cicatrização de uma falha óssea induzida no rádio de coelhos. Foram coletados 10,5mL de sangue por via intracardíaca, o qual foi distribuído em três tubos de hemossedimentação contendo citrato de sódio. Os tubos contendo as amostras foram submetidos a uma centrifugação a 2.000rpm (670,8G por 20 minutos, e da coluna de sedimentação foram aspirados de cada tubo 1.000µL de plasma para a redução do volume sobrenadante. Aspirou-se o plasma acima do anel de leucócitos e transferiu-se para outro tubo para centrifugação a 2.000rpm por 10 minutos. O conteúdo plaquetário no fundo do tubo foi ressuspendido e homogeneizado a 1.000µL do plasma sobrenadante para formar o PRP líquido. Uma falha de 1,0cm foi realizada no rádio esquerdo de cada coelho. O tempo de consolidação foi observado por meio de exame radiográfico aos 45 e 90 dias de pós-operatório (PO. As imagens foram comparadas entre o grupo controle (G1 e o grupo que recebeu o implante de PRP por via transdérmica (G2. A evolução da cicatrização foi verificada com auxílio do programa Adobe Photoshop CC e em uma escala de cinza que representa o contraste. No G2 foi verificada média de 63% de contraste aos 45 dias de PO e de 65% aos 90 dias de PO. No G2, aos 45 dias de PO, a média encontrada foi de 42,7%, e aos 90 dias de PO, 31,25%, indicando que houve evolução do processo de reparação óssea em comparação ao grupo que não recebeu o implante de PRP. O método de obtenção de plasma rico em plaqueta autólogo de coelhos reduziu o número de leucócitos e hemácias e recuperou o número de plaquetas, sendo este maior ou igual aos valores fisiológicos para a espécie. O PRP obtido foi capaz de acelerar o processo de consolidação óssea em coelhos.

  18. Hidrolisado de mucosa intestinal de suínos em substituição ao plasma sangüíneo em dietas para leitões de 21 a 49 dias Hydrolyzed of intestinal mucosa of swine in substitution to blood plasma in diets of pigs from 21 to 49 days

    Anderson Corassa

    2007-12-01

    Full Text Available Um experimento foi conduzido para avaliar o efeito da substituição parcial ou total do plasma sangüíneo por hidrolisado de mucosa intestinal de suínos (HI em dietas para leitões de 21 a 49 dias. Cento e quarenta leitões desmamados aos 21,7 ± 2,9 dias com peso médio de 5,54 ± 0,65 kg foram distribuídos em um delineamento experimental de blocos ao acaso, com cinco tratamentos, sete repetições e quatro animais por unidade experimental. O experimento foi dividido nas fases de 21 a 35 dias e de 36 a 49 dias de idade. Os tratamentos consistiram de uma dieta com plasma e de quatro dietas contendo diferentes níveis dos produtos HI 50 e HI 62 em substituição ao plasma. A substituição parcial ou total do plasma pelos produtos HI 50 e HI 62 não resultou em diferenças no consumo médio diário, no ganho de peso médio diário e na conversão alimentar de leitões nos períodos avaliados. Os pesos absoluto e relativo das vísceras funcionais não foram afetados pelos tratamentos. Não houve efeito das dietas sobre as características de integridade intestinal no duodeno, jejuno e íleo de leitões com 35 dias de idade. Os produtos HI 50 e HI 62 podem substituir total ou parcialmente o plasma em rações para leitões de 21 a 49 dias de idade sem efeitos significativos.A trial was conduced to evaluate the effect partial or total substitution of blood plasma for hydrolyzed of intestinal mucosa of swine (HI in diets of pigs from 21 to 49 days of age. A total of 140 piglets weaned at 21.7 ± 2.9 days of age with average weight of 5.54 ± 0.65 kg were allotted to a randomized experimental block design, with five treatments, seven replications of four animals per experimental unit. The experiment was divided in the phases from 21 to 35 days and from 36 to 49 days of age. The treatments consisted of a diet with plasma and four diets with different levels of HI 50 and HI 62 products in substitution of plasma. The partial or total plasma

  19. Study, analysis and design of plasma torch for the elimination of hospital wastes in Chile; Estudio, analisis y diseno de antorcha de plasma para eliminacion de residuos hospitalarios en Chile

    Diaz Ramirez, Ximena Jesus

    2014-07-01

    Within the field of new technologies in industry, the use of plasma is notable for its high speed of expansion and development. Currently one of its uses is the elimination of waste as it allows to avoid problems such as the formation of airborne byproducts and hazardous solids that represent a serious problem for the environment and human health. Plasma, when it is at extreme temperatures above 3,000 Celsius, causes inorganic waste to disintegrate and to vitrify on a solid residue while organic waste is converted into gases. Unlike any other thermal treatment of waste (incineration, gasification, pyrolysis, etc.) and because it is not a combustion process, but atomization of matter, no pollutant emissions into the atmosphere (dioxins and similar) or ash, there are only simple gases and an inert solid completely vitrified that can be used in the construction, for the obtaining of urban furniture, as decorative element, for example. The project proposes to develop an experimental device, laboratory plasma torch, to investigate its application in the reduction of hospital waste. It is expected to model, design and construct an experimental device that produces a plasma jet, whose temperature is adequate to perform hospital waste treatments at the laboratory level. The main objective of the project is to contribute to the generation of knowledge in the field of hospital waste reduction through the use of technological applications of plasmas, generating the necessary research for the study of art and technological development at the experimental level in the indicated field.

  20. Recubrimientos protectores para componentes de turbinas de aviación y de generación de energía depositados por proyección por plasma

    Agüero Bruna, A.

    2000-08-01

    Full Text Available Coatings produced by aluminium diffusion, called aluminide are employed to increase the oxidation and corrosion resistance, increasing the life of Ni and Co base superalloys components at temperatures comprised between 900 and 1050ºC. Consequently these coatings are frequently employed in aeronautic and power generation turbines as well as in the chemical industry. Aluminides are industrially produced by pack cementation or CVD and recently it has been demonstrated that its resistance significantly increases when Cr is added (chrome-aluminides. During this work, a feasibility study has been carried out in order to determine if plasma spray can be employed for depositing this type of coatings on turbine blades. Therefore, aluminium and aluminium/chromium layers were deposited on Ni base IN100 superalloy specimens that were subsequently subjected to a diffusion heat treatment under Ar flow. Characterisation and analysis of the coatings were carried out by metallography , SEM and EDS. Cyclic oxidation tests were carried out at 1050º C while molten sulphate hot corrosion was performed at 900º C. The results of this preliminary study are promising and indicate that plasma spray can be developed as an industrial process for production of aluminide and chrome-aluminide coatings.

    Los recubrimientos producidos por difusión de aluminio, llamados aluminuros, se emplean para aumentar la resistencia a la oxidación y a la corrosión, incrementando la vida de componentes fabricados con superaleaciones de níquel y cobalto a temperaturas comprendidas entre 900 y 1050º C. Por ello se emplean muy frecuentemente en turbinas aeronaúticas y de producción de energía y en la industria química. Los aluminuros se obtienen industrialmente mediante cementación o CVD y recientemente se ha demostrado que su resistencia aumenta significativamente cuando se añade cromo (cromoaluminuros. Durante el presente trabajo, se ha realizado un estudio de viabilidad

  1. Observaçães sôbre a congelação do plasma humano para desidratação

    Humberto T. Cardoso

    1945-08-01

    Full Text Available A technics for prefreezing of blood plasma and serum is described in this paper. The method indicated by Strumia et al. (2, uses a rapid local freezing to obtain the shell-freezing, with refigerated alcohol bath, at temperatures around minus 35ºC. On our work, it has been found that normal horse blood plasma fulfils the instructions given by Strumia, although normal human blood plasma, very often, fails to give the expected results. This is very disadvantageous at the routine work. With the use of small amounts of solid carbon dioxide, spread over the flasks, in the refrigerated bath, it has been possible to start the chrystallization. The technics prescribes a rapid cooling, like the one used by Strumia, to bring the temperature down, to about plus 10ºC. and, with rotating device stopped, the solid carbon dioxide is applied for one minute simultaneously on each flask. Starting rotation again, it begins to form a very uniform shell around the walls of the flasks.

  2. Numerical Calculation of Transport Based on the Drift-Kinetic Equation for Plasmas in General Toroidal Magnetic Geometry: Convergence and Testing; Calculo Numerico del Transporte mediante la Ecuacion Cinetica de Deriva para Plasmas en Geometria Magnetica Toroidal: Convergencia y Comprobaciones

    Reynolds, J. M.; Lopez-Bruna, D.

    2009-12-11

    This report is the third of a series [Informes Tecnicos Ciemat 1165 y 1172] devoted to the development of a new numerical code to solve the guiding center equation for electrons and ions in toroidal plasmas. Two calculation meshes corresponding to axisymmetric tokamaks are now prepared and the kinetic equation is expanded so the standard terms of neoclassical theory --fi rst order terms in the Larmor radius expansion-- can be identified, restricting the calculations correspondingly. Using model density and temperature profiles for the plasma, several convergence test are performed depending on the calculation meshes and the expansions of the distribution function; then the results are compared with the theory [Hinton and Hazeltine, Rev. Mod. Phys. (1976)]. (Author) 18 refs.

  3. Numerical Calculation of Transport Based on the Drift Kinetic Equation for plasmas in General Toroidal Magnetic Geometry; Calculo Numerico del Transporte mediante la Ecuacion Cinetica de Deriva para Plasmas en Geometria Magnetica Toroidal: Preliminares

    Reynolds, J. M.; Lopez-Bruna, D.

    2009-12-11

    This report is the first of a series dedicated to the numerical calculation of the evolution of fusion plasmas in general toroidal geometry, including TJ-II plasmas. A kinetic treatment has been chosen: the evolution equation of the distribution function of one or several plasma species is solved in guiding center coordinates. The distribution function is written as a Maxwellian one modulated by polynomial series in the kinetic coordinates with no other approximations than those of the guiding center itself and the computation capabilities. The code allows also for the inclusion of the three-dimensional electrostatic potential in a self-consistent manner, but the initial objective has been set to solving only the neoclassical transport. A high order conservative method (Spectral Difference Method) has been chosen in order to discretized the equation for its numerical solution. In this first report, in addition to justifying the work, the evolution equation and its approximations are described, as well as the baseline of the numerical procedures. (Author) 28 refs.

  4. Numerical Calculation of Transport Based on the Drift-Kinetic Equation for Plasmas in General Toroidal Magnetic Geometry: Numerical Methods; Calculo Numerico de Transporte mediante la Ecuacion Cinetica de Deriva para Plasmas en Geometria Magnetica Toroidal: Metodos Numericos

    Reynolds, J. M.; Lopez-Bruna, D.

    2009-10-12

    In this report we continue with the description of a newly developed numerical method to solve the drift kinetic equation for ions and electrons in toroidal plasmas. Several numerical aspects, already outlined in a previous report [Informes Tecnicos Ciemat 1165, mayo 2009], will be treated now in more detail. Aside from discussing the method in the context of other existing codes, various aspects will be now explained from the viewpoint of numerical methods: the way to solve convection equations, the adopted boundary conditions, the real-space meshing procedures along with a new software developed to build them, and some additional questions related with the parallelization and the numerical integration. (Author) 16 refs.

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

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

    2017-10-15

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

  6. Estudio comparativo de técnicas de preparación de muestras para microscopía electrónica de transmisión de recubrimientos cerámicos proyectados por plasma

    Ramírez de Arellano López, A.

    2000-12-01

    Full Text Available The development of advanced materials, with complex microstructures, is a permanent challenge to the development and application of new efficient techniques for microstructural characterization. In ceramic coatings on metals, there exist a differential ion-milling ratio between both components, limiting in principle the use of conventional techniques. In this work, we report on a comparative study of TEM sample preparation techniques for plasma-sprayed ceramic coatings. Firstly, we have used a procedure derived from the conventional one (polishing, dimpling, ion milling, and alternatively a new technique using focused ion-beam milling. The material selected for this study is fine-grained alumina that was plasmasprayed on a steel substrate. The efficiency of both techniques is discussed along with the most significant microstructural features of the material subject of study.

    El desarrollo de materiales avanzados, con microestructuras cada vez más complejas, supone un reto constante de desarrollo y aplicación de técnicas que permitan el análisis de la microestructura de forma eficiente. En el caso de los recubrimientos cerámicos sobre substrato metálico, la diferente velocidad de adelgazamiento iónico que suelen mostrar ambos sistemas supone, en principio, una limitación sustancial. En este trabajo, presentamos un estudio comparativo de la fabricación de láminas delgadas para microscopía electrónica de transmisión, empleando en primer lugar una técnica derivada de la convencional (desbaste, pulido y adelgazamiento iónico, y alternativamente una novedosa técnica de ataque selectivo mediante un haz iónico. El material elegido para realizar este estudio ha sido un recubrimiento de óxido de aluminio de grano fino proyectado por el método de plasma sobre acero. Se discute la eficiencia de cada una de las técnicas, así como las carácteristicas microstructurales más destacadas en el material objeto de estudio.

  7. Development of an automation system for iodine-125 brachytherapy seed production by (Nd:YAG) laser welding; Automacao do processo de soldagem a laser (Nd:YAG) para confeccao das sementes de iodo-125 utilizadas em braquiterapia

    Somessari, Samir Luiz

    2010-07-01

    The aim of this work is to develop an automation system for iodine-125 radioactive seed production by (Nd:YAG) laser welding, which has been used successfully in Low Dose Rate (LDR) brachytherapy treatment. This small seed consists of a welded titanium capsule, with 0.8mm in diameter and 4.5mm in length, containing iodine-125 adsorbed onto a silver rod. The iodine-125 seeds are implanted into the human prostate to irradiate the tumor for cancer treatment. Nowadays, the Radiation Technology Center, at IPEN-CNEN/SP imports and distributes 36,000 iodine-125 seeds per year, for the clinics and hospitals in the country. However, the Brazilian market potential is now over 8,000 iodine-125 seeds per month. The local production of these iodine-125 radioactive sources becomes a priority for the Institute, in order to reduce the price and the problems of prostate cancer management. It will permit to spread their use to a largest number of patients in Brazil. On the other hand, the industrial automation plays an important role for iodine-125 seeds in order to increase the productivity, with high quality and assurance, avoiding human factors, implementing and operating with Good Manufacturing Practices (GMP). The technology consists of appliance electronic and electro-mechanical parts and components to control machines and processes. The automation system technology for iodine-125 seed production developed in this work was mainly assembled employing Programmable Logic Controller (PLC), stepper motors, drivers, (Nd:YAG) laser welding machine, photoelectric sensors and supervisory. (author)

  8. Método analítico por cromatografía líquida de alta resolución para la determinación de carbamazepina en plasma humano Analytical method by high resolution liquid chromatography for the determination of carbamazepine in human plasma

    Narda M. Jiménez Alemán

    2007-04-01

    Full Text Available Entre los requisitos para desarrollar los estudios de biodisponibilidad y bioequivalencia se encuentra contar con metodologías analíticas validadas para el trabajo con muestras en fluidos biológicos. Se desarrolló un método por cromatografía líquida de alta resolución para la determinación de carbamazepina en plasma humano, se utilizó como fase móvil una mezcla de hidrógeno fosfato de sodio: acetonitrilo (65:35 ajustada a pH= 3,3 con ácido fosfórico, flujo de 1,2 mL/min y detección ultravioleta a 210 nm. Se empleó propilparabeno como estándar interno. Conforme con las regulaciones establecidas para la validación de métodos en fluidos biológicos se estudiaron los parámetros siguientes: estabilidad de las muestras, linealidad, especificidad, precisión, exactitud y límite de detección y cuantificación. El método resultó específico y sensible con un límite de detección y cuantificación de 0,9 y 1,0 ng, respectivamente. El método fue lineal, preciso y exacto en el rango de concentraciones de 1,07 a 12,67 µg/mL. La recuperación media no fue estadísticamente diferente del 100,0 %. El analito en la matriz biológica propuesta permaneció en el periodo estudiado. La metodología descrita en este trabajo se aplica en nuestro caso al estudio que evalúa la biodisponibilidad y bioequivalencia de una formulación cubana de carbamazepina en voluntarios sanos.One of the requirements to develop the studies of bioavailability and bioequivalence is to have analytic methodologies validated for the work with samples in biological fluids. A method was developed by high resolution liquid chromatography for the determination of carbamazepine in human plasma. A mixture of hydrogen phosphate of sodium: acetonitrile (65:35 adjusted to pH= 3.3 with phosphoric acid, flow of 1.2 mL/min and ultraviolet detection at 210 nm, was used as mobile phase. Propylparabene was used as an internal standard. According to the established regulations for

  9. Uma metodologia para parametrização do processo MIG/MAG CA A methodology for parameterization of the AC MIG/MAG process

    Américo Scotti

    2012-09-01

    Full Text Available O processo MIG/MAG CA tem um potencial muito grande de aplicação, por permitir unir as características da soldagem MIG/MAG convencional (corrente contínua, com o eletrodo no positivo com as de se usar corrente negativa na soldagem MIG/MAG. Entretanto, o formato de onda de corrente (alternada, pulsada no positivo e constante no negativo demanda uma seleção criteriosa de seus inúmeros parâmetros de regulagem, o que vem limitando o estudo e aplicação desta versão de processo MIG/MAG. O objetivo deste trabalho foi propor e avaliar uma metodologia capaz de estimar os parâmetros de regulagem do processo MIG/MAG CA, de tal forma a se obter soldas com estabilidade de comprimento de arco e cordões com geometria adequada. É feita uma descrição passo a passo da definição dos parâmetros de entrada e da forma de se obter experimentalmente alguns valores de parâmetros necessários para estimação de outros valores de regulagem. As equações de estimação são apresentadas e discutidas. É feita uma demonstração da aplicação da metodologia, com a validação dos resultados pela comparação entre valores estimados e reais.The AC MIG/MAG process presents remarkable application potential, since it allows join the characteristics of the conventional MIG/MAG process (direct current, electrode positive with the ones obtained when negative current is applied in MIG/MAG welding. However, the current wave shape (alternate, pulsed in positive and constant in negative polarities demands a criterions selection of its innumerous setting parameters, fact that limits the development and application of this process version. The objective of this work was to propose and assess a methodology able to estimate the setting parameters of the CA MIG/MAG welding process, in such a way to result in welds with arc length stability and adequate bead geometry. A step-a-step description of the input parameter definitions and of the way to experimentally obtain

  10. Avaliação de soldagem de aço estrutural através do Ruído Magnético de Barkhausen Evaluation of carbon steel welded plates with Magnetic Barkhausen Noise

    Claudia P. Serna-Giraldo

    2010-12-01

    Full Text Available Este trabalho apresenta resultados de avaliação de juntas soldadas de aço estrutural ASTM A36 por meio do Ruído Magnético de Barkhausen (RMB. A soldagem foi feita em chapas de 6 mm de espessura com preparação de chanfro em V, com um e dois passes. Foram feitas a caracterização de microestructuras e microdurezas através da junta soldada, e na superfície foram feitas medições de RMB. Os sinais de RMB foram analisados com o valor máximo, uma média de valores acima de 80% do pico máximo, o rms e o rms do envelope, dos quais foram obtidas curvas da variação com respeito ao centro do cordão e também foram obtidos mapas superficiais. Na caracterização microestructural obteve-se que as amostras de um e dois passes apresentaram tamanhos da zona afetada pelo calor (ZAC diferente. As microdurezas mostraram que no limite de fusão tem-se a maior dureza enquanto que no fim da ZAC tem-se a menor dureza. O RMB mostrou que no limite de fusão tem o menor valor, enquanto que no fim da ZAC tem o maior valor. Este estúdio mostrou que as mudanças na microestrutura influenciam em todos os parâmetros analisados, sendo que a junta soldada ficou melhor representada pelo valor rms e rms do envelope do RMB.This paper shows results for the evaluation of ASTM A36 carbon steel welded joints by Magnetic Barkhausen Noise (MBN. V-groove shape welded samples were made in a 6 mm thickness plates, with one-pass and two-pass. Microstructural and microhardness characterization were made on a transversal section of welds. In the surface was made measurement of MBN. The signal of MBN were analyzed with the maximum value, threshold of 80% above of maximum, the root mean square (rms, the root mean square of the profile, and these parameters were plotted in function of the distance to center bead. Surface maps were obtained, too. The microstructural characterization identified different heat affected zone (HAZ sizes for one-pass and two-pass. In addition

  11. Plasma turbulence

    Horton, W.

    1998-07-01

    The origin of plasma turbulence from currents and spatial gradients in plasmas is described and shown to lead to the dominant transport mechanism in many plasma regimes. A wide variety of turbulent transport mechanism exists in plasmas. In this survey the authors summarize some of the universally observed plasma transport rates

  12. Plasma properties

    Weitzner, H.

    1990-06-01

    This paper discusses the following topics: MHD plasma activity: equilibrium, stability and transport; statistical analysis; transport studies; edge physics studies; wave propagation analysis; basic plasma physics and fluid dynamics; space plasma; and numerical methods

  13. Plasma accelerators

    Bingham, R.; Angelis, U. de; Johnston, T.W.

    1991-01-01

    Recently attention has focused on charged particle acceleration in a plasma by a fast, large amplitude, longitudinal electron plasma wave. The plasma beat wave and plasma wakefield accelerators are two efficient ways of producing ultra-high accelerating gradients. Starting with the plasma beat wave accelerator (PBWA) and laser wakefield accelerator (LWFA) schemes and the plasma wakefield accelerator (PWFA) steady progress has been made in theory, simulations and experiments. Computations are presented for the study of LWFA. (author)

  14. Plasma device

    Thode, L.E.

    1981-01-01

    A method is described for electron beam heating of a high-density plasma to drive a fast liner. An annular or solid relativistic electron beam is used to heat a plasma to kilovolt temperatures through streaming instabilities in the plasma. Energy deposited in the plasma then converges on a fast liner to explosively or ablatively drive the liner to implosion. (U.K.)

  15. Plasma Modes

    Dubin, D. H. E.

    This chapter explores several aspects of the linear electrostatic normal modes of oscillation for a single-species non-neutral plasma in a Penning trap. Linearized fluid equations of motion are developed, assuming the plasma is cold but collisionless, which allow derivation of the cold plasma dielectric tensor and the electrostatic wave equation. Upper hybrid and magnetized plasma waves in an infinite uniform plasma are described. The effect of the plasma surface in a bounded plasma system is considered, and the properties of surface plasma waves are characterized. The normal modes of a cylindrical plasma column are discussed, and finally, modes of spheroidal plasmas, and finite temperature effects on the modes, are briefly described.

  16. Plasma centrifuges

    Karchevskij, A.I.; Potanin, E.P.

    2000-01-01

    The review of the most important studies on the isotope separation processes in the rotating plasma is presented. The device is described and the characteristics of operation of the pulse plasma centrifuges with weakly and strongly ionized plasma as well as the stationary plasma centrifuges with the medium weak ionization and devices, applying the stationary vacuum arc with the high ionization rate and the stationary beam-plasma discharge with complete ionization, are presented. The possible mechanisms of the isotope separation in plasma centrifuges are considered. The specific energy consumption for isotope separation in these devices is discussed [ru

  17. Plasma astrophysics

    Kaplan, S A; ter Haar, D

    2013-01-01

    Plasma Astrophysics is a translation from the Russian language; the topics discussed are based on lectures given by V.N. Tsytovich at several universities. The book describes the physics of the various phenomena and their mathematical formulation connected with plasma astrophysics. This book also explains the theory of the interaction of fast particles plasma, their radiation activities, as well as the plasma behavior when exposed to a very strong magnetic field. The text describes the nature of collective plasma processes and of plasma turbulence. One author explains the method of elementary

  18. Plasma waves

    Swanson, DG

    1989-01-01

    Plasma Waves discusses the basic development and equations for the many aspects of plasma waves. The book is organized into two major parts, examining both linear and nonlinear plasma waves in the eight chapters it encompasses. After briefly discussing the properties and applications of plasma wave, the book goes on examining the wave types in a cold, magnetized plasma and the general forms of the dispersion relation that characterize the waves and label the various types of solutions. Chapters 3 and 4 analyze the acoustic phenomena through the fluid model of plasma and the kinetic effects. Th

  19. Radioimmunoassay method for measurement of plasma androstenedione. Its validation in ovulatory women and in patients with polycystic ovarian syndrome; Metodo de radioimunoensaio para medida da androstenediona plasmatica. Validacao em mulheres ovulatorias e com sindrome dos ovarios policisticos

    Vilanova Socorro Veras, Maria do; Silva e Rosa, Alzira Amelia; Moura, Marcos Dias de; Ferriano, Rui Alberto; Sa, Marcos Felipe Silva de [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Medicina

    1995-01-01

    The present paper has as objective the standardization of a radioimmunoassay method for measurement of androstenedione. Ethyl ether was used for plasma extraction. The sensitivity of the method was 6,8 pg/tube; the reproducibility (inter assay error) was 15,6%; the precision (intrassay error) was 5,2%. As biological control, 20 ovulatory women showed median plasma values of 1250 pg/ml and 24 women with polycystic ovary syndrome presented median plasma values of 2.037 pg/ml. (author). 6 refs., 2 figs., 1 tab.

  20. Plasma device

    Thode, L.E.

    1981-01-01

    A method is described of providing electron beam heating of a high-density plasma to drive a fast liner to implode a structured microsphere. An annular relativistic electron beam is used to heat an annular plasma to kilovolt temperatures through streaming instabilities in the plasma. Energy deposited in the annular plasma then converges on a fast liner to explosively or ablatively drive the liner to convergence to implode the structured microsphere. (U.K.)

  1. Argon plasma coagulation and hyperbaric oxygen therapy in chronic radiation proctopathy, effectiveness and impact on tissue toxicity Argón plasma y oxígeno hiperbárico para el control de la rectorragia crónica secundaria a la proctopatía por radiación

    Julio César Álvaro-Villegas

    2011-11-01

    Full Text Available Background: chronic radiation proctopathy (CRP is associated with recurrent rectal bleeding and transfusional requirements. Argon plasma coagulation (APC and hyperbaric oxygen therapy (HOT have been shown to be effective in the control of CRP. No prospective comparisons have been reported between these treatments. Aim: the aim was to evaluate the effectiveness, safety and impact on tissue toxicity of APC compared to HOT in patients with CRP. Material and methods: a prospective study for evaluating treatment response was conducted. Patients with cervical cancer and CRP with rectal bleeding were recruited. They had not received previous treatment. Collected data included: demographics, previous radiation dosage, duration and severity of rectal bleeding. Hemoglobin, transfusional requirements, and tissue toxicity (SOMA LENT questionnaire at baseline and at 1, 2, and 3 months follow up were recorded. Results: thirty-one patients were included, 14 in the APC group and 17 in the HOT group. No response was noted in 13 and 18% of patients in the APC and HOT group respectively (p = NS. At the 1 and 2 months follow-up, the APC group showed a significantly better response in terms of transfusional requirements (0.6 vs. 3.4 and 0.7 vs. 2.5 and tissue toxicity score (5.3 vs. 8.6 and 3.8 vs. 7.248. After 3 months, both groups showed further improvement in all parameters without significant differences between them. Conclusions: APC and HOT were effective, safe and decreased the tissue toxicity scores in patients with CRP. However, response rate was higher and faster in the APC group.Introducción: la proctopatía por radiación (PPR se asocia con rectorragía recurrente y requerimientos de trasfusiones. La coagulación con argón plasma (APC y la terapia con oxígeno hiperbárico (HOT han sido efectivas en el control de la PPR. No hay estudios prospectivos comparativos entre ambas técnicas. Objetivo: el objetivo del estudio es evaluar la efectividad

  2. Dusty plasmas

    Jones, M.E.; Winske, D.; Keinigs, R.; Lemons, D.

    1996-01-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project has been to develop a fundamental understanding of dusty plasmas at the Laboratory. While dusty plasmas are found in space in galactic clouds, planetary rings, and cometary tails, and as contaminants in plasma enhanced fabrication of microelectronics, many of their properties are only partially understood. Our work has involved both theoretical analysis and self-consistent plasma simulations to understand basic properties of dusty plasmas related to equilibrium, stability, and transport. Such an understanding can improve the control and elimination of plasma dust in industrial applications and may be important in the study of planetary rings and comet dust tails. We have applied our techniques to the study of charging, dynamics, and coagulation of contaminants in plasma processing reactors for industrial etching and deposition processes and to instabilities in planetary rings and other space plasma environments. The work performed in this project has application to plasma kinetics, transport, and other classical elementary processes in plasmas as well as to plasma waves, oscillations, and instabilities

  3. Plasma chromatography

    Anon.

    1984-01-01

    This book examines the fundamental theory and various applications of ion mobility spectroscopy. Plasma chromatography developed from research on the diffusion and mobility of ions. Topics considered include instrument design and description (e.g., performance, spectral interpretation, sample handling, mass spectrometry), the role of ion mobility in plasma chromatography (e.g., kinetic theory of ion transport), atmospheric pressure ionization (e.g., rate equations), the characterization of isomers by plasma chromatography (e.g., molecular ion characteristics, polynuclear aromatics), plasma chromatography as a gas chromatographic detection method (e.g., qualitative analysis, continuous mobility monitoring, quantitative analysis), the analysis of toxic vapors by plasma chromatography (e.g., plasma chromatograph calibration, instrument control and data processing), the analysis of semiconductor devices and microelectronic packages by plasma chromatography/mass spectroscopy (e.g., analysis of organic surface contaminants, analysis of water in sealed electronic packages), and instrument design and automation (hardware, software)

  4. Diseño conceptual de una sonda Langmüir para caracterización de plasmas fríos mediante diseño estadístico de experimentos.

    Victor Hugo Camargo Suarez; Diego Andrés Acosta Maya; Juan Manuel Jaramillo O

    2013-01-01

    La caracterización y control de los procesos asistidos por plasma, se ha convertido en una necesidad cada vez más apremiante en el contexto industrial. Una de las técnicas más versátil y económica es la espectroscopia por métodos electrostáticos. En este trabajo se planteó el diseño y construcción de un sistema de caracterización de plasmas fríos por métodos electrostáticos (Sonda de Langmüir), basado en los conceptos de la física de plasmas y herramientas propias de la ingeniería como diseño...

  5. para palmito

    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.

  6. Diseño conceptual de una sonda Langmüir para caracterización de plasmas fríos mediante diseño estadístico de experimentos.

    Victor Hugo Camargo Suarez

    2013-01-01

    Full Text Available La caracterización y control de los procesos asistidos por plasma, se ha convertido en una necesidad cada vez más apremiante en el contexto industrial. Una de las técnicas más versátil y económica es la espectroscopia por métodos electrostáticos. En este trabajo se planteó el diseño y construcción de un sistema de caracterización de plasmas fríos por métodos electrostáticos (Sonda de Langmüir, basado en los conceptos de la física de plasmas y herramientas propias de la ingeniería como diseño estadístico de experimentos y el diseño conceptual. El resultado de éste trabajo consistió en el diseño conceptual, la construcción de una sonda y la verificación experimental del funcionamiento de la misma, en un reactor de plasma empleando diseño de experimentos.

  7. Plasma physics

    Drummond, James E

    1961-01-01

    A historic snapshot of the field of plasma physics, this fifty-year-old volume offers an edited collection of papers by pioneering experts in the field. In addition to assisting students in their understanding of the foundations of classical plasma physics, it provides a source of historic context for modern physicists. Highly successful upon its initial publication, this book was the standard text on plasma physics throughout the 1960s and 70s.Hailed by Science magazine as a ""well executed venture,"" the three-part treatment ranges from basic plasma theory to magnetohydrodynamics and microwa

  8. Plasma generator

    Omichi, Takeo; Yamanaka, Toshiyuki.

    1976-01-01

    Object: To recycle a coolant in a sealed hollow portion formed interiorly of a plasma limiter itself to thereby to cause direct contact between the coolant and the plasma limiter and increase of contact area therebetween to cool the plasma limiter. Structure: The heat resulting from plasma generated during operation and applied to the body of the plasma limiter is transmitted to the coolant, which recycles through an inlet and outlet pipe, an inlet and outlet nozzle and a hollow portion to hold the plasma limiter at a level less than a predetermined temperature. On the other hand, the heater wire is, at the time of emergency operation, energized to heat the plasma limiter, but this heat is transmitted to the limiter body to increase the temperature thereof. However, the coolant recycling the hollow portion comes into direct contact with the limiter body, and since the plasma limiter surround the hollow portion, the heat amount transmitted from the limiter body to the coolant increases to sufficiently cool the plasma limiter. (Yoshihara, H.)

  9. ADIÇÃO DE PLASMA BOVINO EM SALMOURAS PARA INJEÇÃO DE COXÃO DURO BOVINO (m. BICEPS FEMORIS E SEUS EFEITOS NO PH E NA CARGA MICROBIANA DE BIFES COZIDOS, EMBALADOS A VÁCUO E MANTIDOS SOB REFRIGERAÇÃO

    Ana Lúcia da Silva Corrêa LEMOS

    2010-12-01

    Full Text Available

    As características físicas (pH e microbiológicas (contagem total de psicrotrófi cos e bactérias lácticas de coxão duro bovino (m. Biceps femoris submetido à injeção de salmouras isentas de polifosfatos, adicionadas de agentes bacteriostáticos, lactato de sódio e diacetato de sódio e contendo plasma bovino líquido (PLL e PLO ou plasma bovino desidratado (PDL e PDO, foram avaliadas juntamente com cortes injetados com salmouras isentas de plasma, contendo polifosfatos e com os mesmos agentes bacteriostáticos (CL e CO e cortes não injetados in natura (IN, perfazendo sete tratamentos de bifes embalados a vácuo, provenientes dos cortes íntegros após cozimento, mantidos sob refrigeração (6°C durante 43 dias.Os tratamentos injetados crus e após cozimento não diferiram entre si quanto ao pH, embora, o pH do IN cru tenha sido inferior ao do cozido. A adição de plasma bovino líquido ou desidratado não afetou a carga bacteriana nos cortes íntegros após cocção, mas elevou a carga bacteriana de todos os tratamentos injetados quando comparados aos isentos de plasma (CL e CO ao longo da estocagem sob refrigeração dos bifes embalados a vácuo. A temperatura de armazenamento (6ºC, comum durante a distribuição e exposição de carnes resfriadas no varejo, foi um dos fatores determinantes para a redução da qualidade microbiológica, pois infl uenciou na velocidade do crescimento dos microrganismos deterioradores, especialmente nas salmouras adicionadas de plasma.

  10. Efeito da energia de soldagem sobre a microestrutura e propriedades mecânicas da zona afetada pelo calor de juntas de aço inoxidável duplex Effect of the welding heat input on the microstructure and mechanical properties of the heat affected zone of multipass welded joints of duplex stainless steel

    Everton Barbosa Nunes

    2011-09-01

    Full Text Available O objetivo deste trabalho é analisar a influência da energia de soldagem na zona afetada pelo calor (ZAC, de juntas soldadas do aço inoxidável duplex UNS S31803. Foram realizadas soldagens com eletrodo revestido AWS E2209-17 em junta tipo V de Aço Inoxidável Duplex UNS S31803, com dois níveis de energia (15 e 20 kJ/cm. A condição soldada com energia mais elevada apresentou uma ZAC mais extensa e microestrutura mais grosseira nos passes de acabamento. No entanto, nos passes de enchimento e de raiz, as ZAC's destas regiões foram mais refinadas e menos extensa. Em relação à microdureza, a condição soldada com energia de 15 kJ/cm apresentou níveis menores. Em relação à tenacidade, não foi verificada diferença significativa nos resultados.The aim this work is to evaluate the influence of multipass welding heat input on the microstructure and mechanical properties of the heat affected zone (HAZ of UNS S31803 duplex stainless steel multipass welded joints. The shielded metal arc welding process using as filler metal the AWS E2209-17 covered electrode were employed had been carried through V joint groove UNS S31803 DSS, so that two levels of energy (15 and 20 kJ/cm had been used in this experiment. The condition welded with higher energy higher a HAZ extensive and coarser microstructure in the finishing passes. On the other hand, in the wadding passes and root pass, the HAZ this region was more refined and less extensive. In respect of microhardness, the condition welded with energy of 15 kJ/cm got lower levels. In relation to toughness, it was not observed significant differences.

  11. Estudo pré-analítico e de validação para determinação de malondialdeído em plasma humano por cromatografia líquida de alta eficiência, após derivatização com 2,4-dinitrofenilhidrazina Preanalytical and validation studies for the determination of malondialdehyde in human plasma through high performance liquid chromatography after derivatization with 2,4-dinitrophenylhydrazine

    Marina Venzon Antunes

    2008-06-01

    Full Text Available O malondialdeído (MDA é um importante biomarcador utilizado na avaliação do estresse oxidativo. O objetivo deste estudo foi desenvolver uma metodologia para a quantificação plasmática de MDA, através de cromatografia líquida de alta eficiência com detecção por arranjo de diodos (CLAE-DAD, após processo de derivatização com 2,4-dinitrofenilhidrazina (DNPH, avaliando as principais variáveis pré-analíticas. A curva de calibração em plasma (0 a 40 µM apresentou elevada linearidade (r²=0,998. Os principais parâmetros de validação foram: recuperação absoluta: 78%; limite de detecção: 0,11 µM e limite de quantificação: 0,38 µM. Os valores de MDA determinados em indivíduos adultos saudáveis (n=38 foram 3,31 ± 0,38 µM (média ± DP. Estudos de estabilidade do padrão de MDA, reagente derivatizante e MDA plasmáticos, indicaram que a solução padrão pode ser armazenada a -20 e 4 ºC.Malondialdehyde (MDA is an important biomarker for the evaluation of oxidative stress status. The aim of this study was to develop a method for plasma MDA quantification by high performance liquid chromatography with diode-array detection (HPLC-DAD, following derivatization with 2,4-dinitrophenylhydrazine (DNPH, evaluating the main preanalytical variables. The calibration curve in plasma (0 to 40 µM presented high linearity (r² = 0.998. Main validation parameters were: recovery: 78%; LOD: 0.11 µM and LOQ: 0.38 µM. The MDA values obtained in healthy volunteers (n=38 were 3.31 ± 0.38 µM (mean ± SD. Stability studies of MDA standard solution and derivatizing reagent and plasma MDA indicated that the standard solution can be stored at -20 and 4 ºC, remaining stable for at least 30 days.

  12. Bridge between fusion plasma and plasma processing

    Ohno, Noriyasu; Takamura, Shuichi

    2008-01-01

    In the present review, relationship between fusion plasma and processing plasma is discussed. From boundary-plasma studies in fusion devices new applications such as high-density plasma sources, erosion of graphite in a hydrogen plasma, formation of helium bubbles in high-melting-point metals and the use of toroidal plasmas for plasma processing are emerging. The authors would like to discuss a possibility of knowledge transfer from fusion plasmas to processing plasmas. (T. Ikehata)

  13. Plasma waves

    Swanson, D. G

    1989-01-01

    ... Swanson, D.G. (Donald Gary), D a t e - Plasma waves. Bibliography: p. Includes index. 1. Plasma waves. QC718.5.W3S43 1989 ISBN 0-12-678955-X I. Title. 530.4'4 88-34388 Printed in the United Sta...

  14. Plasma properties

    Weitzner, H.

    1991-06-01

    The Magneto-Fluid Dynamics Division continues to study a broad range of problems originating in plasma physics. Its principal focus is fusion plasma physics, and most particularly topics of particular significance for the world magnetic fusion program. During the calendar year 1990 we explored a wide range of topics including RF-induced transport as a plasma control mechanism, edge plasma modelling, further statistical analysis of L and H mode tokamak plasmas, antenna design, simulation of the edge of a tokamak plasma and the L-H transition, interpretation of the CCT experimental results at UCLA, turbulent transport, studies in chaos, the validity of moment approximations to kinetic equations and improved neoclassical modelling. In more basic studies we examined the statistical mechanisms of Coulomb systems and applied plasma ballooning mode theory to conventional fluids in order to obtain novel fluid dynamics stability results. In space plasma physics we examined the problem of reconnection, the effect of Alfven waves in space environments, and correct formulation of boundary conditions of the Earth for waves in the ionosphere

  15. Plasma container

    Ebisawa, Katsuyuki.

    1985-01-01

    Purpose: To enable to easily detect that the thickness of material to be abraded is reduced to an allowable limit from the outerside of the plasma container even during usual operation in a plasma vessel for a thermonuclear device. Constitution: A labelled material is disposed to the inside or rear face of constituent members of a plasma container undergoing the irradiation of plasma particles. A limiter plate to be abraded in the plasma container is composed of an armour member and heat removing plate, in which the armour member is made of graphite and heat-removing plate is made of copper. If the armour member is continuously abraded under the effect of sputtering due to plasma particles, silicon nitride embedded so far in the graphite at last appears on the surface of the limiter plate to undergo the impact shocks of the plasma particles. Accordingly, abrasion of the limiter material can be detected by a detector comprising gas chromatography and it can easily be detected from the outside of the plasma content even during normal operation. (Horiuchi, T.)

  16. Estudio sobre las formas de presentación de una galleta nutritiva a base de proteína de plasma sanguíneo de bovino para niños en edad escolar

    Alizo, María Alexandra; Márquez Salas, Enrique J.

    2009-01-01

    Debido a la carencia en la producción de proteínas en los países en desarrollo, diferentes alternativas han sido propuestas, una de ellas es la utilización de las proteínas del plasma sanguíneo como suplemento alimenticio. El presente estudio tuvo por objetivo determinar, mediante pruebas de degustación, las características físicas (sabor, forma, diseño de empaque) y aceptación por parte de los niños de bajos recursos de una galleta nutritiva elaborada a base de plasma sanguíneo. La metodolog...

  17. Sistema em fluxo para determinação espectrofotométrica de uréia em plasma de sangue animal empregando leguminosa como fonte natural da enzima urease

    Luca Gilmara C.

    2001-01-01

    Full Text Available A spectrophotometric flow injection analysis (FIA procedure employing natural urease enzyme source for the determination of urea in animal blood plasma was developed. Among leguminous plants used in the Brazilian agriculture, the Cajanus cajan specie was selected as urease source considering its efficiency and availability. A minicolumn was filled with leguminous fragments and coupled to the FIA manifold, where urea was on-line converted to ammonium ions and subsequently it was quantified by spectrophotometry. The system was employed to determine urea in animal plasma samples without any prior treatment. Accuracy was assessed by comparison results with those obtained employing the official procedure and no significant difference at 90 % confidence level was observed. Other profitable features such as an analytical throughput of 30 determinations per hour, a reagent consumption of 19.2 mg sodium salicylate, 0.5 mg sodium hipochloride and a relative standard deviation of 1.4 % (n= 12 were also obtained.

  18. A importância da análise de especiação do chumbo em plasma para a avaliação dos riscos à saúde

    Moreira Fátima R.

    2004-01-01

    Full Text Available Lead absorption is influenced by the species that are formed and the physicochemical characteristics of lead, among others. Lead plasma concentration is < 5% of total blood lead and represents the biologically active fraction able to cross the cell membranes. Health risks mainly depend on a specific metal and its species. Speciation analysis is the analytical activity of identifying and determining different metal species. Chromatographic methods are very useful in the identification of species and the techniques most used to determine metals in biological fluids are ICP OES/MS and AAS. Lead speciation analysis in blood plasma is fundamental for understanding and evaluating the interaction mechanisms between that analyte and its biological targets.

  19. Cosmic plasma

    Alfven, H [California Univ., San Diego, La Jolla (USA)

    1981-01-01

    The properties of space plasmas are analyzed, based on laboratory results and data obtained by in situ measurements in the magnetosphere (including the heliosphere). Attention is given to the question of how much knowledge can be gained by a systematic comparison of different regions of plasma, and plasmas are considered with linear dimensions varying from laboratory size up to the Hubble distance. The traditional magnetic field description of plasmas is supplemented by an electric current description and it is demonstrated that many problems are easier to understand with a dualistic approach. Using the general plasma properties obtained, the origin and evolution of the solar system is summarized and the evolution and present structure of the universe (cosmology) is discussed.

  20. Plasma device

    Thode, L.E.

    1981-01-01

    A relativistic electron beam generator or accelerator produces a high-voltage electron beam which is modulated to initiate electron bunching within the beam which is then applied to a high-density target plasma which typically comprises DT, DD, or similar thermonuclear gas at a density of 10 17 to 10 20 electrons per cubic centimeter. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region of the high-density plasma target. The high-temperature plasma can be used to heat a high Z material to generate radiation. Alternatively, a tunable radiation source is produced by using a moderate Z gas or a mixture of high Z and low Z gas as the target plasma. (author)

  1. Superconducting plasmas

    Ohnuma, Toshiro; Ohno, J.

    1994-01-01

    Superconducting (SC) plasmas are proposed and investigated. The SC plasmas are not yet familiar and have not yet been studied. However, the existence and the importance of SC plasmas are stressed in this report. The existence of SC plasmas are found as follows. There is a fundamental property of Meissner effect in superconductors, which shows a repulsive effect of magnetic fields. Even in that case, in a microscopic view, there is a region of magnetic penetration. The penetration length λ is well-known as London's penetration depth, which is expressed as δ = (m s /μ 0 n s q s 2 ) 1/2 where m s , n s , q s and μ o show the mass, the density, the charge of SC electron and the permeability in free space, respectively. Because this expression is very simple, no one had tried it into more simple and meaningful form. Recently, one of the authors (T.O.) has found that the length can be expressed into more simple and understandable fundamental form as λ = c/ω ps where c = (ε 0 μ 0 ) -1/2 and ω ps = (n s q s 2 /m s ε 0 ) 1/2 are the light velocity and the superconducting plasma frequency. From this simple expression, the penetration depth of the magnetic field to SC is found as a SC plasma skin depth, that is, the fundamental property of SC can be expressed by the SC plasmas. This discovery indicates an importance of the studies of superconducting plasmas. From these points, several properties (propagating modes et al) of SC plasmas, which consist of SC electrons, normal electrons and lattice ions, are investigated in this report. Observations of SC plasma frequency is also reported with a use of Terahertz electromagnet-optical waves

  2. Plasma universe

    Alfven, H.

    1986-04-01

    Traditionally the views in our cosmic environment have been based on observations in the visual octave of the electromagnetic spectrum, during the last half-century supplemented by infrared and radio observations. Space research has opened the full spectrum. Of special importance are the X-ray-gamma-ray regions, in which a number of unexpected phenomena have been discovered. Radiations in these regions are likely to originate mainly from magnetised cosmic plasma. Such a medium may also emit synchrotron radiation which is observable in the radio region. If we try to base a model of the universe on the plasma phenomena mentioned we find that the plasma universe is drastically different from the traditional visual universe. Information about the plasma universe can also be obtained by extrapolation of laboratory experiments and magnetospheric in situ measurements of plasma. This approach is possible because it is likely that the basic properties of plasma are the same everywhere. In order to test the usefulness of the plasma universe model we apply it to cosmogony. Such an approach seems to be rather successful. For example, the complicated structure of the Saturnian C ring can be accounted for. It is possible to reconstruct certain phenomena 4-5 bilions years ago with an accuracy of better than 1 percent

  3. Plasma physics

    1979-01-01

    This report contains the papers delivered at the AEB - Natal University summer school on plasma physics held in Durban during January 1979. The following topics were discussed: Tokamak devices; MHD stability; trapped particles in tori; Tokamak results and experiments; operating regime of the AEB Tokamak; Tokamak equilibrium; high beta Tokamak equilibria; ideal Tokamak stability; resistive MHD instabilities; Tokamak diagnostics; Tokamak control and data acquisition; feedback control of Tokamaks; heating and refuelling; neutral beam injection; radio frequency heating; nonlinear drift wave induced plasma transport; toroidal plasma boundary layers; microinstabilities and injected beams and quasilinear theory of the ion acoustic instability

  4. Plasma centrifuge

    Ikehata, Takashi; Mase, Hiroshi

    1998-01-01

    The plasma centrifuge is one of statistical isotope separation processes which uses the centrifugal force of a J x B driven rotating plasma in a magnetic field to give rise to the mass-dependent radial transport of isotopic ions. The system has been developed as an alternative to the gas centrifuge because a much higher rotational velocity and separation factor have been achieved. In this review, the physical aspects of the plasma centrifuge followed by the recent experimental achievements are described, especially in comparison with the gas centrifuge. (author)

  5. Complementação por coagulação com plasma de argônio após a ressecção endoscópica completa pela técnica de fatiamento para grandes adenomas colorretais

    Walton Albuquerque

    Full Text Available OBJETIVO: avaliar a eficácia da complementação por coagulação com plasma de argônio para reduzir a taxa de neoplasia residual ou recorrente após ressecção endoscópica completa fragmentada de grandes adenomas sésseis colorretais. MÉTODOS: critérios de inclusão: pacientes com grandes adenomas colorretais sésseis, > 20mm, sem sinais morfológicos de infiltração profunda, submetidos à ressecção endoscópica completa fragmentada estudada com cromoendoscopia e magnificação de imagens. Os pacientes foram randomizados em dois grupos: grupo 1 - nenhum procedimento adicional e, grupo 2 - complementação por coagulação com plasma de argônio. O seguimento por colonoscopia foi realizado em três, seis e 12 meses de pós-operatório. Foi avaliada a taxa de neoplasia residual ou recidiva local. RESULTADOS: foram incluídos no estudo um total de 21 lesões. Onze lesões no grupo 1 e dez no grupo 2. Ocorreram duas neoplasias residuais ou recorrências locais em cada grupo, detectadas em três meses de acompanhamento. CONCLUSÃO: a complementação por coagulação com plasma de argônio após uma aparente ressecção endoscópica completa em fragmentos de grandes adenomas sésseis colorretais não parece reduzir a ocorrência de lesão adenomatosa residual ou recidiva local.

  6. Plasma Cleaning

    Hintze, Paul E.

    2016-01-01

    NASA's Kennedy Space Center has developed two solvent-free precision cleaning techniques: plasma cleaning and supercritical carbon dioxide (SCCO2), that has equal performance, cost parity, and no environmental liability, as compared to existing solvent cleaning methods.

  7. Laser Plasmas

    -focusing in a plasma ... Center for Energy Studies, Indian Institute of Technology, New Delhi 110 016, India; Tata Consultancy Services, Gurgaon, India; Ideal Institute of Technology, Ghaziabad, India; Center for Research in Cognitive, ...

  8. Plasma will…

    Lunov, Oleg

    2016-01-01

    Roč. 174, č. 3 (2016), s. 486-487 ISSN 0007-0963 Institutional support: RVO:68378271 Keywords : plasma * ionized gas Subject RIV: BO - Biophysics OBOR OECD: Biophysics Impact factor: 4.706, year: 2016

  9. Plasma technology

    Drouet, M.G.

    1984-03-01

    IREQ was contracted by the Canadian Electrical Association to review plasma technology and assess the potential for application of this technology in Canada. A team of experts in the various aspects of this technology was assembled and each team member was asked to contribute to this report on the applications of plasma pertinent to his or her particular field of expertise. The following areas were examined in detail: iron, steel and strategic-metals production; surface treatment by spraying; welding and cutting; chemical processing; drying; and low-temperature treatment. A large market for the penetration of electricity has been identified. To build up confidence in the technology, support should be provided for selected R and D projects, plasma torch demonstrations at full power, and large-scale plasma process testing

  10. Plasma metallization

    Crowther, J.M.

    1997-09-01

    Many methods are currently used for the production of thin metal films. However, all of these have drawbacks associated with them, for example the need for UHV conditions, high temperatures, exotic metal precursors, or the inability to coat complex shaped objects. Reduction of supported metal salts by non-isothermal plasma treatment does not suffer from these drawbacks. In order to produce and analyse metal films before they become contaminated, a plasma chamber which could be attached directly to a UHV chamber with XPS capability was designed and built. This allowed plasma treatment of supported metal salts and surface analysis by XPS to be performed without exposure of the metal film to the atmosphere. Non-equilibrium plasma treatment of Nylon 66 supported gold(lll) chloride using hydrogen as the feed gas resulted in a 95% pure gold film, the remaining 5% of the film being carbon. If argon or helium were used as the feed gases during plasma treatment the resultant gold films were 100% pure. Some degree of surface contamination of the films due to plasma treatment was observed but was easily removed by argon ion cleaning. Hydrogen plasma reduction of glass supported silver(l) nitrate and palladium(ll) acetate films reveals that this metallization technique is applicable to a wide variety of metal salts and supports, and has also shown the ability of plasma reduction to retain the complex 'fern-like' structures seen for spin coated silver(l) nitrate layers. Some metal salts are susceptible to decomposition by X-rays. The reduction of Nylon 66 supported gold(lll) chloride films by soft X-rays to produce nanoscopic gold particles has been studied. The spontaneous reduction of these X-ray irradiated support gold(lll) chloride films on exposure to the atmosphere to produce gold rich metallic films has also been reported. (author)

  11. Plasma confinement

    Hazeltine, R D

    2003-01-01

    Detailed and authoritative, this volume examines the essential physics underlying international research in magnetic confinement fusion. It offers readable, thorough accounts of the fundamental concepts behind methods of confining plasma at or near thermonuclear conditions. Designed for a one- or two-semester graduate-level course in plasma physics, it also represents a valuable reference for professional physicists in controlled fusion and related disciplines.

  12. Plasma Diagnostics

    Zaveryaev, V [Kurchatov Institute, Moscow (Russian Federation); others, and

    2012-09-15

    The success in achieving peaceful fusion power depends on the ability to control a high temperature plasma, which is an object with unique properties, possibly the most complicated object created by humans. Over years of fusion research a new branch of science has been created, namely plasma diagnostics, which involves knowledge of almost all fields of physics, from electromagnetism to nuclear physics, and up-to-date progress in engineering and technology (materials, electronics, mathematical methods of data treatment). Historically, work on controlled fusion started with pulsed systems and accordingly the methods of plasma parameter measurement were first developed for short lived and dense plasmas. Magnetically confined hot plasmas require the creation of special experimental techniques for diagnostics. The diagnostic set is the most scientifically intensive part of a plasma device. During many years of research operation some scientific tasks have been solved while new ones arose. New tasks often require significant changes in the diagnostic system, which is thus a very flexible part of plasma machines. Diagnostic systems are designed to solve several tasks. As an example here are the diagnostic tasks for the International Thermonuclear Experimental Reactor - ITER: (1) Measurements for machine protection and basic control; (2) Measurements for advanced control; (3) Additional measurements for performance evaluation and physics. Every new plasma machine is a further step along the path to the main goal - controlled fusion - and nobody knows in advance what new phenomena will be met on the way. So in the planning of diagnostic construction we should keep in mind further system upgrading to meet possible new scientific and technical challenges. (author)

  13. Setting-up and validation of two radioimmunoassay methods for determination of plasma progesterone concentration in mares, cows and rats; Padronizacao e validacao de dois metodos de radioimunoensaio (RIE) para dosagem da progesterona (P{sub 4}) no plasma de equinos, bovinos e ratos

    Rosa e Silva, A A.M.; Caldas, M C.S.; Campos, L M.A. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Fac. de Medicina. Dept. de Fisiologia; Gradela, A [UNESP, Jaboticabal, SP (Brazil). Faculdade de Ciencias Agrarias e Veterinarias

    1993-06-01

    Two reliable radioimmunoassay (RIA) methods which permits the measurement of progesterone (P{sub 4}) in plasma of equine, bovine and rats are described. After extraction of plasma with diethylic ether the RIA methods were performed. The first one utilizes {sup 125} I progesterone (double antibody method) and the other 1,2,6,7,16, 17 {sup 3} H progesterone (adsorption in charcoal/dextran). Both two methods were suitable in the valuation of plasma P{sub 4} concentration in different physiological reproductive conditions. The method of the double antibody showed higher sensibility beyond to be less expensive than the other method. Despite it, the two RIA methods were much less expensive than available commercial Kits in the market. (author) 14 refs., 2 figs., 1 tab.

  14. Estudo da Técnica Tig Keyhole por Meio do Análise Comparativo entre Duas Tochas de Alta Produtividade na União de Chapas de Aço Carbono de Meia Espessura

    Olivares, Erick Alejandro González; Silva, Régis Henrique Gonçalves e; Dutra, Jair Carlos

    2015-01-01

    Resumo Na bibliografia de referência comum, a soldagem por meio da técnica Keyhole sempre foi associada a processos de soldagem com uma alta concentração de energia, como o processo Laser ou o processo Plasma. Novos avanços em tochas TIG estão mudando a forma em como o processo de soldagem TIG deveria ser considerado. Um exemplo desses novos avanços é a tocha comercialmente conhecida como Infocus, que segundo seus fabricantes a principal característica da tocha é a capacidade de concentração ...

  15. Cold plasmas

    Franz, G.

    1990-01-01

    This textbook discusses the following topics: Phenomenological description of a direct current glow discharge; the plasma (temperature distribution and measurement, potential variation, electron energy distribution function, charge neutralization, wall potentials, plasma oscillations); Production of charge carriers (ions, electrons, ionization in the cathode zone, negative glowing zone, Faraday dark space, positive column, anode zone, hollow cathode discharges); RF-discharges (charge carrier production, RF-Shields, scattering mechanisms); Sputtering (ion-surface interaction, kinetics, sputtering yield and energy distribution, systems and conditions, film formation and stresses, contamination, bias techniques, multicomponent film deposition, cohesion, magnetrons, triode systems, plasma enhanced chemical vapor deposition); Dry etching (sputter etching, reactive etching, topography, process control, quantitative investigations); Etching mechanisms (etching of Si and SiO 2 with CF 4 , of III/V-compound-semiconductors, combination of isotrope and anisotrope etching methods, surface cleaning); ion beam systems (applications, etching); Dyclotron-resonance-systems (electron cyclotron resonance systems, whistler-sources and 'resonant inductive plasma etching'); Appendix (electron energy distribution functions, Bohm's transition zone, plasma oscillations, scattering cross sections and mean free path, metastable states, Child-Langmuir-Schottky equation, loss mechanisms, charge carrier distribution in the positive column, breakdown at high frequencies, motion in a magnetic field, skin depth of an electric field for a HF-discharge, whistler waves, dispersion relations for plane wave propagation). (orig.) With 138 figs

  16. Plasma heating

    Wilhelm, R.

    1989-01-01

    Successful plasma heating is essential in present fusion experiments, for the demonstration of DpT burn in future devices and finally for the fusion reactor itself. This paper discusses the common heating systems with respect to their present performance and their applicability to future fusion devices. The comparative discussion is oriented to the various function of heating, which are: - plasma heating to fusion-relevant parameters and to ignition in future machines, -non-inductive, steady-pstate current drive, - plasma profile control, -neutral gas breakdown and plasma build-up. In view of these different functions, the potential of neutral beam injection (NBI) and the various schemes of wave heating (ECRH, LH, ICRH and Alven wave heating) is analyzed in more detail. The analysis includes assessments of the present physical and technical state of these heating methods, and makes suggestions for future developments and about outstanding problems. Specific attention is given to the still critical problem of efficient current drive, especially with respect to further extrapolation towards an economically operating tokamak reactor. Remarks on issues such as reliability, maintenance and economy conclude this comparative overview on plasma heating systems. (author). 43 refs.; 13 figs.; 3 tabs

  17. Análise da passividade e adaptação de infraestruturas de Ti com soldagem a laser vertical e horizontal de borda, cilindro cimentado ou processo CAD/CAM

    Maíra Daysê Moreira Serra e Silva

    2013-01-01

    Resumo: Este estudo comparou diferentes técnicas para obtenção de infraestruturas protéticas implantossuportadas com menores desajustes verticais e melhor passividade. A partir de uma matriz metálica com paredes planas e dimensões de altura, comprimento e espessura de 25 X 70 X 10 mm, contendo 4 análogos de microunits (3,75 X 13 mm), foram confeccionadas 25 amostras separadas em cinco grupos (n=5): Grupo IM infraestruturas fundidas em monobloco; Grupo ISS infraestruturas fundidas seccionadas ...

  18. PLASMA DEVICE

    Gow, J.D.; Wilcox, J.M.

    1961-12-26

    A device is designed for producing and confining highenergy plasma from which neutrons are generated in copious quantities. A rotating sheath of electrons is established in a radial electric field and axial magnetic field produced within the device. The electron sheath serves as a strong ionizing medium to gas introdueed thereto and also functions as an extremely effective heating mechanism to the resulting plasma. In addition, improved confinement of the plasma is obtained by ring magnetic mirror fields produced at the ends of the device. Such ring mirror fields are defined by the magnetic field lines at the ends of the device diverging radially outward from the axis of the device and thereafter converging at spatial annular surfaces disposed concentrically thereabout. (AFC)

  19. Plasma properties

    Weitzner, H.

    1989-08-01

    A cursory examination of the research activities of the Magneto-Fluid Dynamics Division for the calendar year 1988 shows the effects of the gradual transformation of the group. Although our principal activity, fusion plasma physics research, is unchanged, the work shows closer ties to problems relevant to present experiments than previously. Most notable is the concentrated effort on tokamak equilibrium and transport. We are exploring the implication of turbulence induced transport, resistive MHD effects, neoclassical transport, and possible interpretations of transport based on classical phenomena. In addition, one of our members has chosen to focus on problems of enhanced statistical methods for interpretation of experiments. All of this activity preceded the Tokamak Transport Initiative and reflects our active involvement and concern with the world-wide tokamak program. Since equilibrium and transport are by no means the only theoretical plasma physics problems affecting fusion devices we continue substantial efforts in wave propagation and heating, particle simulation of plasmas, stability theory, enhancement of numerical algorithms, and general plasma physics. We are attempting to develop effective numerical schemes for the Boltzmann equation, adaptive grid methods for MHD, and particle simulation of boundary and antenna effects. Many of these topics reflect our continuing concern to maintain a modest effort in the development of theoretical models and tools for problems of real significance to fusion, but not necessarily of immediate highest priority. We select problems which we expect to become extremely important in the future. Our space plasma physics activities, funded by agencies other than DOE, transfers knowledge learned in fusion plasma physics to another area and conversely stimulates work also relevant to fusion problems

  20. Electron plasma waves and plasma resonances

    Franklin, R N; Braithwaite, N St J

    2009-01-01

    In 1929 Tonks and Langmuir predicted of the existence of electron plasma waves in an infinite, uniform plasma. The more realistic laboratory environment of non-uniform and bounded plasmas frustrated early experiments. Meanwhile Landau predicted that electron plasma waves in a uniform collisionless plasma would appear to be damped. Subsequent experimental work verified this and revealed the curious phenomenon of plasma wave echoes. Electron plasma wave theory, extended to finite plasmas, has been confirmed by various experiments. Nonlinear phenomena, such as particle trapping, emerge at large amplitude. The use of electron plasma waves to determine electron density and electron temperature has not proved as convenient as other methods.

  1. ''Dusty plasmas''

    Tsytovich, V.N.; Bingham, R.; Angelis, U. de

    1989-09-01

    The field of ''dusty plasmas'' promises to be a very rewarding topic of research for the next decade or so, not only from the academic point of view where the emphasis is on developing the theory of the often complex collective and non-linear processes, but also from the point of view of applications in astrophysics, space physics, environmental and energy research. In this ''comment'' we should like to sketch the current development of this fast growing and potentially very important research area. We will discuss the new features of ''dusty'' plasmas in the most general terms and then briefly mention some successful applications and effects which have already been examined. (author)

  2. Plasma physics and engineering

    Fridman, Alexander

    2011-01-01

    Part I: Fundamentals of Plasma Physics and Plasma ChemistryPlasma in Nature, in the Laboratory, and in IndustryOccurrence of Plasma: Natural and Man MadeGas DischargesPlasma Applications, Plasmas in IndustryPlasma Applications for Environmental ControlPlasma Applications in Energy ConversionPlasma Application for Material ProcessingBreakthrough Plasma Applications in Modern TechnologyElementary Processes of Charged Species in PlasmaElementary Charged Particles in Plasma and Their Elastic and Inelastic CollisionsIonization ProcessesMechanisms of Electron Losses: The Electron-Ion RecombinationEl

  3. Revascularización pulpar mediante la utilización de plasma rico en plaquetas autólogo o en combinación con una matriz colágena, como posibilidades terapéuticas para dientes con ápice abierto, pulpa necrótica y/o patología periapical.

    Paula Alejandra Camargo Guevara

    2014-07-01

    Full Text Available Objetivo: describir el uso del plasma rico en plaquetas autólogo o en combinación con una matriz colágena como posibilidades terapéuticas de revascularización en dientes con ápices abiertos, pulpa necrótica y/o lesión periapical. Métodos: se realizó una búsqueda temática de la literatura entre los años 2007 y 2013, por medios electrónicos, bases de datos, revistas y journals con alto impacto en endodoncia. Resultados: la endodoncia regenerativa es un procedimiento biológico diseñado para reemplazar estructuras lesionadas, enfermas o ausentes del complejo pulpo-dentinal. Hay tres factores que guían y permiten la regeneración tisular: células madre mesenquimales (MSC, que pueden diferenciarse y apoyar la continuación en el desarrollo radicular, factores de crecimiento (GF, para la inducción de la proliferación celular y la diferenciación, y un andamio adecuado que brinde soporte y promueva la migración, crecimiento y la diferenciación celular. El colágeno y el plasma rico en plaquetas (PRP han sido reportados como andamios de elección en la regeneración endodóntica, se dice que estimulan la formación de tejido, la organización y la adherencia celular, mejorando el tiempo de tratamiento y de evolución. Conclusiones: en los procedimientos de revascularización, elegir un andamio o soporte tridimensional como el colágeno tipo I o PRP sumado a la inducción de los tejidos periapicales, aumenta las posibilidades de éxito en el tratamiento de regeneraciónendodóntica gracias a las propiedades que brindan y a la interacción molecular.

  4. Plasma chromograninx

    Goetze, Jens P; Hilsted, Linda M; Rehfeld, Jens F

    2014-01-01

    Cardiovascular risk assessment remains difficult in elderly patients. We examined whether chromogranin A (CgA) measurement in plasma may be valuable in assessing risk of death in elderly patients with symptoms of heart failure in a primary care setting. A total of 470 patients (mean age 73 years...

  5. Burning plasmas

    Furth, H.P.; Goldston, R.J.; Zweben, S.J.

    1990-10-01

    The fraction of fusion-reaction energy that is released in energetic charged ions, such as the alpha particles of the D-T reaction, can be thermalized within the reacting plasma and used to maintain its temperature. This mechanism facilitates the achievement of very high energy-multiplication factors Q, but also raises a number of new issues of confinement physics. To ensure satisfactory reaction operation, three areas of energetic-ion interaction need to be addressed: single-ion transport in imperfectly symmetric magnetic fields or turbulent background plasmas; energetic-ion-driven (or stabilized) collective phenomena; and fusion-heat-driven collective phenomena. The first of these topics is already being explored in a number of tokamak experiments, and the second will begin to be addressed in the D-T-burning phase of TFTR and JET. Exploration of the third topic calls for high-Q operation, which is a goal of proposed next-generation plasma-burning projects. Planning for future experiments must take into consideration the full range of plasma-physics and engineering R ampersand D areas that need to be addressed on the way to a fusion power demonstration

  6. Magnetoresistive waves in plasmas

    Felber, F.S.; Hunter, R.O. Jr.; Pereira, N.R.; Tajima, T.

    1982-01-01

    The self-generated magnetic field of a current diffusing into a plasma between conductors can magnetically insulate the plasma. Propagation of magnetoresistive waves in plasmas is analyzed. Applications to plasma opening switches are discussed

  7. Plasma physics

    Cairns, R A

    1985-01-01

    This book is intended as an introduction to plasma physics at a level suitable for advanced undergraduates or beginning postgraduate students in physics, applied mathematics or astrophysics. The main prerequisite is a knowledge of electromagnetism and of the associated mathematics of vector calculus. SI units are used throughout. There is still a tendency amongst some plasma physics researchers to· cling to C.g.S. units, but it is the author's view that universal adoption of SI units, which have been the internationally agreed standard since 1960, is to be encouraged. After a short introductory chapter, the basic properties of a plasma con­ cerning particle orbits, fluid theory, Coulomb collisions and waves are set out in Chapters 2-5, with illustrations drawn from problems in nuclear fusion research and space physics. The emphasis is on the essential physics involved and (he theoretical and mathematical approach has been kept as simple and intuitive as possible. An attempt has been made to draw attention t...

  8. Plasma shutdown device

    Hosogane, Nobuyuki; Nakayama, Takahide.

    1985-01-01

    Purpose: To prevent concentration of plasma currents to the plasma center upon plasma shutdown in a torus type thermonuclear device by the injection of fuels to the plasma center thereby prevent plasma disruption at the plasma center. Constitution: The plasma shutdown device comprises a plasma current measuring device that measures the current distribution of plasmas confined within a vacuum vessel and outputs a control signal for cooling the plasma center when the plasma currents concentrate to the plasma center and a fuel supply device that supplies fuels to the plasma center for cooling the center. The fuels are injected in the form of pellets into the plasmas. The direction and the velocity of the injection are set such that the pellets are ionized at the center of the plasmas. (Horiuchi, T.)

  9. Estrategias para negociaciones exitosas.

    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....

  10. Plasma spot welding of ferritic stainless steels

    Lešnjak, A.

    2002-06-01

    Full Text Available Plasma spot welding of ferritic stainless steels is studied. The study was focused on welding parameters, plasma and shielding gases and the optimum welding equipment. Plasma-spot welded overlap joints on a 0.8 mm thick ferritic stainless steel sheet were subjected to a visual examination and mechanical testing in terms of tension-shear strength. Several macro specimens were prepared. Plasma spot welding is suitable to use the same gas as shielding gas and as plasma gas, i.e., a 98 % Ar/2 % H 2 gas mixture. Tension-shear strength of plasma-spot welded joints was compared to that of resistance-spot welded joints. It was found that the resistance welded joints withstand a somewhat stronger load than the plasma welded joints due to a larger weld spot diameter of the former. Strength of both types of welded joints is approximately the same.

    El artículo describe el proceso de soldeo de aceros inoxidables ferríticos por puntos con plasma. La investigación se centró en el establecimiento de los parámetros óptimos de la soldadura, la definición del gas de plasma y de protección más adecuado, así como del equipo óptimo para la realización de la soldadura. Las uniones de láminas de aceros inoxidables ferríticos de 0,8 mm de espesor, soldadas a solape por puntos con plasma, se inspeccionaron visualmente y se ensayaron mecánicamente mediante el ensayo de cizalladura por tracción. Se realizaron macro pulidos. Los resultados de la investigación demostraron que la solución más adecuada para el soldeo por puntos con plasma es elegir el mismo gas de plasma que de protección. Es decir, una mezcla de 98 % de argón y 2 % de hidrógeno. La resistencia a la cizalladura por tracción de las uniones soldadas por puntos con plasma fue comparada con la resistencia de las uniones soldadas por resistencia por puntos. Se llegó a la conclusión de que las uniones soldadas por resistencia soportan una carga algo mayor que la uniones

  11. PARAFAC: uma ferramenta quimiométrica para tratamento de dados multidimensionais. Aplicações na determinação direta de fármacos em plasma humano por espectrofluorimetria PARAFAC: a chemometric tool for multi-dimensional data treatment. Applications in direct determination of drugs in human plasma by spectrofluorimetry

    Marcelo M. Sena

    2005-10-01

    Full Text Available Since the last decade, the combined use of chemometrics and molecular spectroscopic techniques has become a new alternative for direct drug determination, without the need of physical separation. Among the new methodologies developed, the application of PARAFAC in the decomposition of spectrofluorimetric data should be highlighted. The first objective of this article is to describe the theoretical basis of PARAFAC. For this purpose, a discussion about the order of chemometric methods used in multivariate calibration and the development of multi-dimensional methods is presented first. The other objective of this article is to divulge for the Brazilian chemical community the potential of the combination PARAFAC/spectrofluorimetry for the determination of drugs in complex biological matrices. For this purpose, two applications aiming at determining, respectively, doxorrubicine and salicylate in human plasma are presented.

  12. Subvenciones para instituciones Directrices para gastos de ...

    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.

  13. Plasma focus breeder

    Ikuta, Kazunari.

    1981-09-01

    Instead of using linear accelerators, it is possible to breed fissile fuels with the help of high current plasma focus device. A mechanism of accelerating proton beam in plasma focus device to high energy would be a change of inductance in plasma column because of rapid growth of plasma instability. A possible scheme of plasma focus breeder is also proposed. (author)

  14. Estudo da soldagem de tubos de aço inoxidável duplex e superduplex na posição 5G Study of the welding of duplex and superduplex stainless steel pipes in the 5G position

    Pedro Ivo Guimarães de Vasconcellos

    2010-09-01

    Full Text Available Os aços inoxidáveis duplex e superduplex possuem uma microestrutura austeno-ferrítica com fração média de cada fase de cerca 50%. A microestrutura duplex é responsável pelas excelentes propriedades mecânicas, especialmente o limite de escoamento e a tenacidade, e pela elevada resistência a corrosão por pites e sob tensão em meios contendo cloretos. A soldagem destes aços é frequentemente uma operação crítica. Neste trabalho, um tubo de superduplex SAF 2207 foi soldado pelo processo TIG (GTAW no passe de raiz e eletrodo revestido (SMAW nos passes de enchimento, e um tubo de duplex SAF 2205 foi todo soldado pelo processo GTAW. A microestrutura do metal base, zona afetada termicamente (ZTA e metal de solda foi caracterizada e quantificada. As propriedades de tenacidade, resistência a corrosão e composição química foram avaliadas e correlacionadas. Os valores de tenacidade ao impacto Charpy-V foram considerados adequados. Não foi observada a precipitação de intermetálicos, carbonetos e nitretos. O melhor resultado no teste de corrosão da junta soldada de aço inox superduplex, comparado ao duplex, foi atribuído ao baixo teor de ferrita delta na solda e ZTA, e composição química da solda enriquecida em Cr, Mo, W e N.The duplex and superduplex stainless steels have an austenitic-ferritic microstructure with an average fraction of each phase of approximately 50%. This duplex microstructure is responsible for the excellent mechanical properties, specially the yield strength and toughness, and for the improved pitting and stress corrosion cracking resistance in chloride environments. Welding of these steels is often a critical operation. In this work, a superduplex stainless steel SAF 2507 pipe was welded by the GTAW process in the root pass and by SMAW process on filler passes, and one pipe of duplex SAF 2205 was entirely welded by the GTAW process. The microstructure of the base metal, heat affected zone (HAZ and weld

  15. Plasma rico em plaquetas na Implantologia

    Rego, Luis André Ferreira Lopes

    2014-01-01

    Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária As reabilitações orais implanto-suportadas resolveram grandes limitações das próteses removíveis convencionais. No entanto, o tempo de espera e o sucesso no tratamento com implantes trouxeram novos desafios, tal como o uso de concentrados autólogos de plaquetas para promoção da osteointegração. O plasma rico em plaquetas é definido c...

  16. Plasma Free Metanephrines

    ... Links Patient Resources For Health Professionals Subscribe Search Plasma Free Metanephrines Send Us Your Feedback Choose Topic ... Images View Sources Ask Us Also Known As Plasma Metanephrines Formal Name Fractionated Plasma Free Metanephrines (Metanephrine ...

  17. Improved plasma accelerator

    Cheng, D. Y.

    1971-01-01

    Converging, coaxial accelerator electrode configuration operates in vacuum as plasma gun. Plasma forms by periodic injections of high pressure gas that is ionized by electrical discharges. Deflagration mode of discharge provides acceleration, and converging contours of plasma gun provide focusing.

  18. Experimental study of para- and ortho-H3+ recombination

    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 .

  19. ECR plasma photographs as a plasma diagnostic

    Racz, R; Biri, S; Palinkas, J [Institute of Nuclear Research (ATOMKI), H-4026 Debrecen, Bem ter 18/c (Hungary)

    2011-04-15

    Low, medium or highly charged ions delivered by electron cyclotron resonance (ECR) ion sources all are produced in the ECR plasma. In order to study such plasmas, high-resolution visible light plasma photographs were taken at the ATOMKI ECR ion source. An 8 megapixel digital camera was used to photograph plasmas made from He, methane, N, O, Ne, Ar, Kr, Xe gases and from their mixtures. The analysis of the photo series gave many qualitative and some valuable physical information on the nature of ECR plasmas. A comparison was made between the plasma photos and computer simulations, and conclusions were drawn regarding the cold electron component of the plasma. The warm electron component of similar simulation was compared with x-ray photos emitted by plasma ions. While the simulations are in good agreement with the photos, a significant difference was found between the spatial distribution of the cold and warm electrons.

  20. Plasma physics and fusion plasma electrodynamics

    Bers, Abraham

    2016-01-01

    Plasma is a ubiquitous state of matter at high temperatures. The electrodynamics of plasmas encompasses a large number of applications, from understanding plasmas in space and the stars, to their use in processing semiconductors, and their role in controlled energy generation by nuclear fusion. This book covers collective and single particle dynamics of plasmas for fully ionized as well as partially ionized plasmas. Many aspects of plasma physics in current fusion energy generation research are addressed both in magnetic and inertial confinement plasmas. Linear and nonlinear dynamics in hydrodynamic and kinetic descriptions are offered, making both simple and complex aspects of the subject available in nearly every chapter. The approach of dividing the basic aspects of plasma physics as "linear, hydrodynamic descriptions" to be covered first because they are "easier", and postponing the "nonlinear and kinetic descriptions" for later because they are "difficult" is abandoned in this book. For teaching purpose...

  1. Plasma waves in an inhomogeneous cylindrical plasma

    Pesic, S.S.

    1976-01-01

    The complete dispersion equation governing small amplitude plasma waves propagating in an inhomogeneous cylindrical plasma confined by a helical magnetic field is solved numerically. The efficiency of the wave energy thermalization in the lower hybrid frequency range is studied

  2. Oro para Colombia

    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.

  3. Quiescent plasma machine for plasma investigation

    Ferreira, J.L.

    1993-01-01

    A large volume quiescent plasma device is being developed at INPE to study Langmuir waves and turbulence generated by electron beams (E b ≤ 500 e V) interacting with plasma. This new quiescent plasma machine was designed to allow the performance of several experiments specially those related with laboratory space plasma simulation experiments. Current-driven instabilities and related phenomena such as double-layers along magnetic field lines are some of the many experiments planned for this machine. (author)

  4. Plasma basic concepts and nitrogen containing plasmas

    Sanz Lluch, M. del Mar; Tanarro, Isabel

    2007-01-01

    Basic concepts related to plasmas are described as well as the typical characterization methods currently available. A brief overview about some plasma applications is given, but focusing on plasma used in material processing mainly devoted to the microelectronics industry. Finally, specific applications related to plasma-assisted MBE for nitrides and dilute nitrides are given, showing some interesting research works performed to that purpose, and giving the usual characterization techniques ...

  5. Estrategias para negociaciones exitosas.

    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.

  6. Lectures in plasma diagnostics

    Hutchinson, I.H.

    1990-06-01

    This paper discusses the following topics on plasma diagnostics: Electric probes in flowing and magnetized plasmas; Electron cyclotron emission absorption; Magnetic diagnostics; Spectroscopy; and Thomson Scattering

  7. Plasma electron losses in a multidipole plasma

    Haworth, M.D.

    1983-01-01

    The magnitude of the plasma electron cusp losses in a multidipole plasma device is determined by using a plasma electron heating technique. This method consists of suddenly generating approximately monoenergetic test electrons inside the multidipole plasma, which is in a steady-state equilibrium prior to the introduction of the test electrons. The Coulomb collisions between the test electrons and the plasma electrons result in heating the plasma electrons. The experimentally measured time evolution of the plasma electron temperature is compared with that predicted by a kinetic-theory model which calculates the time evolution of the test electron and the plasma electron distribution functions. The analytical solution of the plasma electron heating rate when the test electrons are first introduced into the plasma predicts that there is no dependence on ion mass. Experimental results in helium, neon, argon, and krypton multidipole plasmas confirm this prediction. The time-evolved solution of the kinetic equations must be solved numerically, and these results (when coupled with the experimental heating results) show that the plasma electron cusp-loss width is on the order of an electron Larmor radius

  8. Physics of plasma etching and plasma deposition

    Schram, D.C.; Hoog, de F.J.; Bisschops, T.J.; Kroesen, G.M.W.; Howorka, F.; Lindinger, W.; Maerk, T.D.

    1986-01-01

    The kinetics and mechanism of the title processes are discussed on the basis of a model in which the plasma-surface system is subdivided into 5 regions: (I) plasma prodn., (II) plasma flow plus radicals, (III) gas adsorbed layer, (IV) modified surface, and (V) undisturbed solid (or liq.) state.

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

    Oliveira, Thiago Cesar de

    2014-06-01

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

  10. Fusion plasma physics

    Stacey, Weston M

    2012-01-01

    This revised and enlarged second edition of the popular textbook and reference contains comprehensive treatments of both the established foundations of magnetic fusion plasma physics and of the newly developing areas of active research. It concludes with a look ahead to fusion power reactors of the future. The well-established topics of fusion plasma physics -- basic plasma phenomena, Coulomb scattering, drifts of charged particles in magnetic and electric fields, plasma confinement by magnetic fields, kinetic and fluid collective plasma theories, plasma equilibria and flux surface geometry, plasma waves and instabilities, classical and neoclassical transport, plasma-materials interactions, radiation, etc. -- are fully developed from first principles through to the computational models employed in modern plasma physics. The new and emerging topics of fusion plasma physics research -- fluctuation-driven plasma transport and gyrokinetic/gyrofluid computational methodology, the physics of the divertor, neutral ...

  11. Oscillatory processes in plasma

    Gallin, E.

    1980-01-01

    The oscillatory process play an important part in plasma evolution, In hot plasma in particular, the interactions between the oscillation modes are preponderant in relation to the binary collisions between particles. The nonlineary interactions between collective plasma oscillations can generate, in this case, a non-balanced steady state of plasma (steady turbulence). The paper elucidates some aspects of the oscillatory phenomena which contribute to the plasma state evolution, especially of hot plasma. A major part of the paper is devoted to the study of parametric instabilities in plasma and their role in increasing the temperature of plasma components (electrons, ions). Both parametric instabilities in plasma in the vicinity of thermodynamic balance and parametric processes is steady turbulent plasma are analysed - in relation to additional heating of hot plasma. An important result of the thesis refers to the drowing-up of a non-lineary interaction model between the oscillation modes in turbulent plasma, being responsible for the electromagnetic radiation in hot plasma. On the basis of the model suggested in the paper the existence of a low frequency radiative mode in hot plasma in a turbulent state, can be demonstrated. Its frequency could be even lower than plasma frequency in the field of long waves be even lower than plasma frequency in the field of long waves. Such a radiative mode was detected experimentally in focussed plasma installations. (author)

  12. Effect of the welding process on the microstructure and microhardness of API 5L X80 steel welded joint used for oil transportation pipeline; Efeito do processo de soldagem sobre a microestrutura e a microdureza de juntas soldadas de aco API 5L X80 usado em tubulacoes para transporte de petroleo

    Alves, R.T.P.; Albuquerque, S.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil); Maciel, T.M.; Almeida, D.M.; Santos, M.A.

    2008-07-01

    This study had as objective to evaluate the microstructure and microhardness of API 5L X80 steel welded joints, used for pipelines to transport oil and gas, using the Shield Metal Arc Welding process with pre- heating temperature of 200 deg C and 400 deg C and the AWS E8010G electrode as filler metal. For this, besides the microhardness of the welded joint, the weld metals percentiles of micro-constituents and of columnar and regenerated grains and the medium size and extension of the heat affected zone were evaluated. The percentage of acicular ferrite in weld metal ranged from 13% to 33% which generated values of microhardness from 114 HV to 309 HV. (author)

  13. Dust-Plasma Interactions

    Rosenberg, Marelene

    2005-01-01

    Our theoretical research on dust-plasma interactions has concentrated on three main areas: (a)studies of grain charging and applications; (b) waves and instabilities in weakly correlated dusty plasma with applications to space and laboratory plasmas; (c) waves in strongly coupled dusty plasmas.

  14. Communication through plasma sheaths

    Korotkevich, A. O.; Newell, A. C.; Zakharov, V. E.

    2007-01-01

    We wish to transmit messages to and from a hypersonic vehicle around which a plasma sheath has formed. For long distance transmission, the signal carrying these messages must be necessarily low frequency, typically 2 GHz, to which the plasma sheath is opaque. The idea is to use the plasma properties to make the plasma sheath appear transparent

  15. Plasma Turbulence General Topics

    Kadomtsev, B. B. [Nuclear Energy Institute, Academy of Sciences of the USSR, Moscow, USSR (Russian Federation)

    1965-06-15

    It is known that under experimental conditions plasma often shows chaotic motion. Such motion, when many degrees of freedom are excited to levels considerably above the thermal level, will be called turbulent. The properties of turbulent plasma in many respects differ from the properties of laminar plasma. It can be said that the appearance of various anomalies in plasma behaviour indicates the presence of turbulence in plasma. In order to verify directly the presence of turbulent motion in plasma we must, however, measure the fluctuation of some microscopic parameters in plasma.

  16. Introduction to plasma dynamics

    Morozov, A I

    2013-01-01

    As the twenty-first century progresses, plasma technology will play an increasing role in our lives, providing new sources of energy, ion-plasma processing of materials, wave electromagnetic radiation sources, space plasma thrusters, and more. Studies of the plasma state of matter not only accelerate technological developments but also improve the understanding of natural phenomena. Beginning with an introduction to the characteristics and types of plasmas, Introduction to Plasma Dynamics covers the basic models of classical diffuse plasmas used to describe such phenomena as linear and shock w

  17. Tiempo para un cambio

    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.

  18. Collisionless plasmas in astrophysics

    Belmont, Gerard; Mottez, Fabrice; Pantellini, Filippo; Pelletier, Guy

    2013-01-01

    Collisionless Plasmas in Astrophysics examines the unique properties of media without collisions in plasma physics. Experts in this field, the authors present the first book to concentrate on collisionless conditions in plasmas, whether close or not to thermal equilibrium. Filling a void in scientific literature, Collisionless Plasmas in Astrophysics explains the possibilities of modeling such plasmas, using a fluid or a kinetic framework. It also addresses common misconceptions that even professionals may possess, on phenomena such as "collisionless (Landau) damping". Abundant illustrations

  19. Experimental plasma physics

    Dreicer, H.; Banton, M.E.; Ingraham, J.C.; Wittman, F.; Wright, B.L.

    1976-01-01

    The Experimental Plasma Physics group's main efforts continue to be directed toward the understanding of the mechanisms of electromagnetic energy absorption in a plasma, and the resultant plasma heating and energy transport. The high-frequency spectrum of plasma waves parametrically excited by the microwave signal at high powers has been measured. The absorption of a small test microwave signal in a plasma made parametrically unstable by a separate high-power driver microwave signal was also studied

  20. Examples of plasma horizons

    Hanni, R.S.

    1975-01-01

    The concept of the plasma horizon, defined as the boundary of the region in which an infinitely thin plasma can be supported against Coulomb attraction by a magnetic field, shows that the argument of selective accretion does not rule out the existence of charged black holes embedded in a conducting plasma. A detailed account of the covariant definition of plasma horizon is given and some examples of plasma horizons are presented. 7 references

  1. Elements of plasma technology

    Wong, Chiow San

    2016-01-01

    This book presents some fundamental aspects of plasma technology that are important for beginners interested to start research in the area of plasma technology . These include the properties of plasma, methods of plasma generation and basic plasma diagnostic techniques. It also discusses several low cost plasma devices, including pulsed plasma sources such as plasma focus, pulsed capillary discharge, vacuum spark and exploding wire; as well as low temperature plasmas such as glow discharge and dielectric barrier discharge which the authors believe may have potential applications in industry. The treatments are experimental rather than theoretical, although some theoretical background is provided where appropriate. The principles of operation of these devices are also reviewed and discussed.

  2. Para-Hermitian and para-quaternionic manifolds

    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)

  3. Para-Hermitian and para-quaternionic manifolds

    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)

  4. TFTR plasma feedback systems

    Efthimion, P.; Hawryluk, R.J.; Hojsak, W.; Marsala, R.J.; Mueller, D.; Rauch, W.; Tait, G.D.; Taylor, G.; Thompson, M.

    1985-01-01

    The Tokamak Fusion Test Reactor employs feedback control systems for four plasma parameters, i.e. for plasma current, for plasma major radius, for plasma vertical position, and for plasma density. The plasma current is controlled by adjusting the rate of change of current in the Ohmic Heating (OH) coil system. Plasma current is continuously sensed by a Rogowski coil and its associated electronics; the error between it and a preprogrammed reference plasma current history is operated upon by a ''proportional-plusintegral-plus-derivative'' (PID) control algorithm and combined with various feedforward terms, to generate compensating commands to the phase-controlled thyristor rectifiers which drive current through the OH coils. The plasma position is controlled by adjusting the currents in Equilibrium Field and Horizontal Field coil systems, which respectively determine the vertical and radial external magnetic fields producing J X B forces on the plasma current. The plasma major radius position and vertical position, sensed by ''B /sub theta/ '' and ''B /sub rho/ '' magnetic flux pickup coils with their associated electronics, are controlled toward preprogrammed reference histories by allowing PID and feedforward control algorithms to generate commands to the EF and HF coil power supplies. Plasma density is controlled by adjusting the amount of gas injected into the vacuum vessel. Time-varying gains are used to combine lineaveraged plasma density measurements from a microwave interferometer plasma diagnostic system with vacuum vessel pressure measurements from ion gauges, with various other measurements, and with preprogrammed reference histories, to determine commands to piezoelectric gas injection valves

  5. International conference on plasma physics

    Silin, V.P.; Sitenko, A.G.

    1985-01-01

    A brief report on the 6th International conference on plasma physics and on the 6th International Congress on plasma waves and plasma instabilities, which have taken place in summer 1984 in Losanne, is presented. Main items of the conference are enlightened, such as the general theory of a plasma, laboratory plasma, thermonuclear plasma, cosmic plasma and astrophysics

  6. Plasmas and fluids

    Anon.

    1986-01-01

    Plasma and fluid physics includes the fields of fusion research and space investigation. This book discusses the most important advances in these areas over the past decade and recommends a stronger commitment to basic research in plasma and fluid physics. The book recommends that plasma and fluid physics be included in physics curriculums because of their increasing importance in energy and defense. The book also lists recent accomplishments in the fields of general plasma physics, fusion plasma confinement and heating, space and astrophysical plasmas, and fluid physics and lists research opportunities in these areas. A funding summary explains how research monies are allocated and suggests ways to improve their effectiveness

  7. Amanteigamento por aspersão térmica na soldagem em operação de dutos de pequena espessura: estabilidade e penetração do arco voltaico Buttering by thermal spraying in welding in-service repair of pipes with small thickness: arc stability and penetration

    Nilceu Novicki

    2011-09-01

    Full Text Available Este trabalho reúne resultados promissores sobre uma via alternativa de reparo em dutos e tubulações em operação com pequena espessura remanescente, envolvendo a recuperação prévia da parede do tubo por amanteigamento por processos de aspersão térmica. Avaliou-se a instabilidade apresentada pelo arco voltaico e alteração do perfil da zona fundida quando da deposição de solda por eletrodos revestidos sobre chapas de aço carbono previamente amanteigadas, com camadas de composição similar, pelos processos de aspersão térmica a chama e a arco-elétrico. Os resultados permitiram correlacionar a estabilidade do arco com o nível de oxidação das camadas aspergidas.( Medidas de temperatura do revestimento aspergido mostraram que, desde que o processo de aspersão ocorra de forma ininterrupta até a espessura final do revestimento, a temperatura superficial é crescente com a espessura do depósito, o que resulta num maior teor de óxidos, associado tanto à uma instabilidade do cordão como à uma maior penetração da poça fundida. Difratogramas de raios-X nas camadas aspergidas e análises do teor de oxigênio na zona fundida dos cordões de solda comprovaram a influência desse elemento na alteração do perfil da zona fundida. Como alternativa ao uso de ar comprimido, foi avaliada sua substituição pelo argônio como gás de arraste, verificando-se efeitos muito benéficos - redução significativa da penetração e boa estabilidade do arco voltaico - admite-se que advindos da redução da oxidação da camada aspergida pelo efeito protetor do gás inerte. A avaliação dos resultados permitiu estabelecer critérios de soldagem com menor risco de perfuração se comparados a uma condição sem revestimento prévio por aspersão térmica.This work brings promising results about an alternative way of welding in-service repair of pipes with low reminiscent thickness, which involves a previous buttering coating of the pipe wall by

  8. Nonthermal Radiation Processes in Interplanetary Plasmas

    Chian, A. C. L.

    1990-11-01

    RESUMEN. En la interacci6n de haces de electrones energeticos con plasmas interplanetarios, se excitan ondas intensas de Langmuir debido a inestabilidad del haz de plasma. Las ondas Langmuir a su vez interaccio nan con fluctuaciones de densidad de baja frecuencia para producir radiaciones. Si la longitud de las ondas de Langmujr exceden las condicio nes del umbral, se puede efectuar la conversi5n de modo no lineal a on- das electromagneticas a traves de inestabilidades parametricas. As se puede excitar en un plasma inestabilidades parametricas electromagneticas impulsadas por ondas intensas de Langmuir: (1) inestabilidades de decaimiento/fusi5n electromagnetica impulsadas por una bomba de Lang- muir que viaja; (2) inestabilidades dobles electromagneticas de decai- miento/fusi5n impulsadas por dos bombas de Langrnuir directamente opues- tas; y (3) inestabilidades de dos corrientes oscilatorias electromagne- ticas impulsadas por dos bombas de Langmuir de corrientes contrarias. Se concluye que las inestabilidades parametricas electromagneticas in- ducidas por las ondas de Langmuir son las fuentes posibles de radiacio- nes no termicas en plasmas interplanetarios. ABSTRACT: Nonthermal radio emissions near the local electron plasma frequency have been detected in various regions of interplanetary plasmas: solar wind, upstream of planetary bow shock, and heliopause. Energetic electron beams accelerated by solar flares, planetary bow shocks, and the terminal shock of heliosphere provide the energy source for these radio emissions. Thus, it is expected that similar nonthermal radiation processes may be responsible for the generation of these radio emissions. As energetic electron beams interact with interplanetary plasmas, intense Langmuir waves are excited due to a beam-plasma instability. The Langmuir waves then interact with low-frequency density fluctuations to produce radiations near the local electron plasma frequency. If Langmuir waves are of sufficiently large

  9. Special issue: Plasma Conversion

    Nozaki, T.; Bogaerts, A.; Tu, X.; van de Sanden, M. C. M.

    2017-01-01

    With growing concern of energy and environmental issues, the combination of plasma and heterogeneous catalysts receives special attention in greenhouse gas conversion, nitrogen fixation and hydrocarbon chemistry. Plasma gas conversion driven by renewable electricity is particularly important for the

  10. Neutrino beam plasma instability

    positron or electron–proton plasma in the context of early universe, stars and supernova ... proper. Of course, in their later work on kinetic theory (KT) [5] of neutrino plasma inter- .... for electron also with additional electric potential term.

  11. Plasma kinetic theory

    Elliott, J.A.

    1993-01-01

    Plasma kinetic theory is discussed and a comparison made with the kinetic theory of gases. The plasma is described by a modified set of fluid equations and it is shown how these fluid equations can be derived. (UK)

  12. Physics of laser plasma

    Rubenchik, A.; Witkowski, S.

    1991-01-01

    This book provides a comprehensive review of laser fusion plasma physics and contains the most up-to-date information on high density plasma physics and radiation transport, useful for astrophysicists and high density physicists

  13. Plasma heating in collisionless plasma at low plasma density

    Wulf, H.O.

    1977-01-01

    The high frequency heating of a collisionless, fully ionized low density plasma is investigated in the range: 2ωc 2 2 under pumping frequencies. A pulsed 1 MHz transmitter excites a fast standing, magneto-acoustical wave in the plasma, via the high frequency magnetic field of a Stix solenoid. The available modulation degrees are between 0.7 and 7.0%. As power consumption measurements show, there appears at all investigated pumping frequencies an effective energy transfer to the plasma that cannot be explained with the classical MHD models. Measurements with electrostatic probes and further with a miniature counter-field spectrometer yield an electron and ion temperature gain of two to three factors and 15-18, compared to the corresponding values in the initial plasma. (orig./HT) [de

  14. ParaChoice Model.

    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.

  15. Universidades accesibles para todos

    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

  16. Educando para la ignorancia

    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.

  17. Introduction to Plasma Physics

    Gurnett, Donald A.; Bhattacharjee, Amitava

    2017-03-01

    Preface; 1. Introduction; 2. Characteristic parameters of a plasma; 3. Single particle motions; 4. Waves in a cold plasma; 5. Kinetic theory and the moment equations; 6. Magnetohydrodynamics; 7. MHD equilibria and stability; 8. Discontinuities and shock waves; 9. Electrostatic waves in a hot unmagnetized plasma; 10. Waves in a hot magnetized plasma; 11. Nonlinear effects; 12. Collisional processes; Appendix A. Symbols; Appendix B. Useful trigonometric identities; Appendix C. Vector differential operators; Appendix D. Vector calculus identities; Index.

  18. Plasma-wall interaction

    Reichle, R.

    2004-01-01

    This document gathers the 43 slides presented in the framework of the week long lecture 'hot plasmas 2004' and dedicated to plasma-wall interaction in a tokamak. This document is divided into 4 parts: 1) thermal load on the wall, power extraction and particle recovery, 2) basic edge plasma physics, 3) processes that drive the plasma-solid interaction, and 4) material conditioning (surface treatment...) for ITER

  19. Plasma physics an introduction

    Fitzpatrick, Richard

    2014-01-01

    Plasma Physics: An Introduction is based on a series of university course lectures by a leading name in the field, and thoroughly covers the physics of the fourth state of matter. This book looks at non-relativistic, fully ionized, nondegenerate, quasi-neutral, and weakly coupled plasma. Intended for the student market, the text provides a concise and cohesive introduction to plasma physics theory, and offers a solid foundation for students wishing to take higher level courses in plasma physics.

  20. Application of plasma focus device to compression of toroidal plasma

    Ikuta, Kazunari

    1980-01-01

    A new concept of compressing a toroidal plasma using a plasma focus device is considered. Maximum compression ratio of toroidal plasma is determined merely by the initial density ratio of the toroidal plasma to a sheet plasma in a focus device because of the Rayleigh-Taylor instability. An initiation senario of plasma-linear is also proposed with a possible application of this concepts to the creation of a burning plasma in reversed field configurations, i.e., burning plasma vortex. (author)

  1. INICIATIVAS PARA EL CAMBIO

    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.

  2. Plasma membrane ATPases

    Palmgren, Michael Broberg; Bækgaard, Lone; Lopez Marques, Rosa Laura

    2011-01-01

    The plasma membrane separates the cellular contents from the surrounding environment. Nutrients must enter through the plasma membrane in order to reach the cell interior, and toxic metabolites and several ions leave the cell by traveling across the same barrier. Biological pumps in the plasma me...

  3. Plasma in wound healing

    Tipa, R.S.

    2012-01-01

    Plasmas, due to their electrical and chemical properties, release in the invironment a unique cocktail of charged species, energetic photons and active radicals. Plasmas have a miriad of applications. To mention just a few, plasmas are being used in the semiconductors industry, atomic layer

  4. Plasma in astrophysics

    Kulsrud, R.M.

    1982-10-01

    Two examples of plasma phenomena of importance to astrophysics are reviewed. These are examples where astrophysical understanding hinges on further progress in plasma physics understanding. The two examples are magnetic reconnection and the collisionless interaction between a population of energetic particles and a cooler gas or plasma, in particular the interaction between galactic cosmic rays and the interstellar medium

  5. Plasma processing and chemistry

    Schram, D.C.; Mullen, van der J.J.A.M.; Sanden, van de M.C.M.

    1994-01-01

    The growing field of applications of plasma as deposition, etching, surface modification and chemical conversion has stimulated a renewed interest in plasma science in the atomic physical chemistry regime. The necessity to optimize the various plasma processing techniques in terms of rates, and

  6. Evaluación in vivo de la eficacia cosmética de dos procedimientos de bioestimulación con la aplicación de plasma rico en plaquetas en arrugas faciales, para mejorar la elasticidad y firmeza de la piel tratada

    Cornejo Bravo, Juan Carlos

    2017-01-01

    Mi proyecto de titulación se orientó a buscar la eficacia cosmética de dos procedimientos de bioestimulación con Plasma Rico en Plaquetas en arrugas faciales, teniendo como resultado que la eficacia se encuentra en personas con mioenvejecimiento (30-40 años) con el procedimiento de Plasma Rico en Plaquetas Activado (PRPA). This project, prior to obtaining my Master’s degree was aimed towards seeking the cosmetic efficiency of two bio stimulation procedures using platelet-rich plasma applie...

  7. Some aspects of plasma thermodynamics

    Gorgoraki, V.I.

    1986-01-01

    The objective reasons which have inhibited the development of a plasma-thermodynamics theory are discussed and the authors formulate the fundamental principles which can be the basis of a common plasma-thermodynamics theory. Two kinds of thermodynamic equilibrium plasmas are discussed, an isothermal plasma and a nonisothermal plasma. An isothermal plasma is a high-temperature plasma; the Saha-Eggert equation describes its behavior. A nonisothermal plasma is a low-temperature plasma, and the reactions taking place therein are purely plasma-chemical. The ionization equilibrium and the composition of such a plasma can be found with the aid of the equations presented in this paper

  8. Space plasma simulation chamber

    1986-01-01

    Scientific results of experiments and tests of instruments performed with the Space Plasma Simulation Chamber and its facility are reviewed in the following six categories. 1. Tests of instruments on board rockets, satellites and balloons. 2. Plasma wave experiments. 3. Measurements of plasma particles. 4. Optical measurements. 5. Plasma production. 6. Space plasms simulations. This facility has been managed under Laboratory Space Plasma Comittee since 1969 and used by scientists in cooperative programs with universities and institutes all over country. A list of publications is attached. (author)

  9. Computations in plasma physics

    Cohen, B.I.; Killeen, J.

    1984-01-01

    A review of computer application in plasma physics is presented. Computer contribution to the investigation of magnetic and inertial confinement of a plasma and charged particle beam propagation is described. Typical utilization of computer for simulation and control of laboratory and cosmic experiments with a plasma and for data accumulation in these experiments is considered. Basic computational methods applied in plasma physics are discussed. Future trends of computer utilization in plasma reseaches are considered in terms of an increasing role of microprocessors and high-speed data plotters and the necessity of more powerful computer application

  10. Model of detached plasmas

    Yoshikawa, S.; Chance, M.

    1986-07-01

    Recently a tokamak plasma was observed in TFTR that was not limited by a limiter or a divertor. A model is proposed to explain this equilibrium, which is called a detached plasma. The model consists of (1) the core plasma where ohmic heating power is lost by anomalous heat conduction and (2) the shell plasma where the heat from the core plasma is radiated away by the atomic processes of impurity ions. A simple scaling law is proposed to test the validity of this model

  11. Mirror plasma apparatus

    Moir, R.W.

    1981-01-01

    A mirror plasma apparatus which utilizes shielding by arc discharge to form a blanket plasma and lithium walls to reduce neutron damage to the wall of the apparatus. An embodiment involves a rotating liquid lithium blanket for a tandem mirror plasma apparatus wherein the first wall of the central mirror cell is made of liquid lithium which is spun with angular velocity great enough to keep the liquid lithium against the first material wall, a blanket plasma preventing the lithium vapor from contaminating the plasma

  12. Contemporary plasma physics

    Sodha, M.S.; Tewari, D.P.; Subbarao, D.

    1983-01-01

    The book consists of review articles on some selected contemporary aspects of plasma physics. The selected topics present a panoramic view of contemporary plasma physics and applications to fusion, space and MHD power generation. Basic non-linear plasma theory is also covered. The book is supposed to be useful for M.S./M.Sc. students specialising in plasma physics and for those beginning research work in plasma physics. It will also serve as a valuable reference book for more advanced research workers. (M.G.B.)

  13. ECR Plasma Photos

    Racz, R.; Biri, S.; Palinkas, J.

    2009-01-01

    Complete text of publication follows. In order to observe and study systematically the plasma of electron cyclotron resonance (ECR) ion sources (ECRIS) we made a high number of high-resolution visible light plasma photos and movies in the ATOMKI ECRIS Laboratory. This required building the ECR ion source into an open plasma device, temporarily. An 8MP digital camera was used to record photos of plasmas made from He, methane, N, O, Ne, Ar, Kr, Xe gases and from their mixtures. The effects of the main external setting parameters (gas pressure, gas composition, magnetic field, microwave power, microwave frequency) were studied to the shape, color and structure of the plasma. The double frequency mode (9+14 GHz) was also realized and photos of this special 'star-in-star' shape plasma were recorded. A study was performed to analyze and understand the color of the ECR plasmas. The analysis of the photo series gave us many qualitative and numerous valuable physical information on the nature of ECR plasmas. To our best knowledge our work is the first systematic study of ECR plasmas in the visible light region. When looking in the plasma chamber of an ECRIS we can see an axial image of the plasma (figure 1) in conformity with experimental setup. Most of the quantitative information was obtained through the summarised values of the Analogue Digital Unit (ADU) of pixels. By decreasing the strength of the magnetic trap we clearly observed that the brightness of the central part of the plasma gradually decreases, i.e. the plasma becomes more and more 'empty'. Figure 2 shows a photo series of ECR plasma at decreasing axial magnetic field. The radial size of the plasma increased because of the ascendant resonant zone. By increasing the power of the injected microwave an optimum (or at least saturation) was found in the brightness of the plasma. We found correlation between the gas dosing rates and plasma intensities. When sweeping the frequency of the microwave in a wide region

  14. Cyclotron waves in plasma

    Lominadze, D G

    2013-01-01

    Cyclotron Waves in Plasma is a four-chapter text that covers the basic physical concepts of the theory of cyclotron waves and cyclotron instabilities, brought about by the existence of steady or alternating plasma currents flowing perpendicular to the magnetic field.This book considers first a wide range of questions associated with the linear theory of cyclotron oscillations in equilibrium plasmas and in electron plasmas in metals and semiconductors. The next chapter deals with the parametric excitation of electron cyclotron oscillations in plasma in an alternating electric field. A chapter f

  15. Introduction to plasma engineering

    Roth, J.R.

    1988-01-01

    The author has begun writing a textbook entitled Introduction to Plasma Engineering, which is intended for upper division undergraduates or professionals who are entering the field. This paper features a detailed topical outline of all 20 chapters of the book. The text is organized so that the first five chapters cover plasma physics and basic principles; the next 13 chapters cover the most important engineering applications of plasmas, in order of increasing plasma energy/number density; and two final chapters cover plasma diagnostics and magnetic coil design

  16. Experimental study of para- and ortho-H3+ recombination

    Plašil, R.; Varju, J.; Hejduk, M.; Dohnal, P.; Kotrík, T.; Glosík, J.

    2011-07-01

    Recombination of H3+ with electrons is a key process for many plasmatic environments. Recent experiments on storage ring devices used ion sources producing H3+ with enhanced populations of H3+ 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-H3+ ions with electrons at 77 K in afterglow plasma in a He/Ar/H2 gas-mixture. Both spin configurations of H3+ have been observed in situ with a near infrared cavity ring down spectrometer (NIR-CRDS) using the two lowest energy levels of H3+. Using hydrogen with an enhanced population of H2 molecules in para states allowed us to influence the [para-H3+]/[ortho-H3+] 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-H3+. Measurements with different fractions of para-H3+ at otherwise identical conditions allowed us to determine the binary recombination rate coefficients for pure para-H3+ pαbin(77 K) = (2.0±0.4)×10-7 cm3s-1 and pure ortho-H3+ oαbin(77 K) = (4±3)×10-8 cm3s-1.

  17. Applied plasma physics

    Anon.

    1979-01-01

    Applied Plasma Physics is a major sub-organizational unit of the Magnetic Fusion Energy (MFE) Program. It includes Fusion Plasma Theory and Experimental Plasma Research. The Fusion Plasma Theory group has the responsibility for developing theoretical-computational models in the general areas of plasma properties, equilibrium, stability, transport, and atomic physics. This group has responsibility for giving guidance to the mirror experimental program. There is a formal division of the group into theory and computational; however, in this report the efforts of the two areas are not separated since many projects have contributions from members of both. Under the Experimental Plasma Research Program we are developing a neutral-beam source, the intense, pulsed ion-neutral source (IPINS), for the generation of a reversed-field configuration on 2XIIB. We are also studying the feasibility of using certain neutron-detection techniques as plasma diagnostics in the next generation of thermonuclear experiments

  18. Plasma polymerization by Softplasma

    Jiang, J.; Wu, Zhenning; Benter, Maike

    2008-01-01

    , external electrode, and electrodeless microwave or high frequency reactors. [3] Softplasma™ is an internal electrode plasma setup powered by low frequenc~ gower supply. It was developed in late 90s for surface treatment of silicone rubber. [ ]- 5] It is a low pressure, low electron density, 3D homogenous......In the late 19th century, the first depositions - known today as plasma polymers, were reported. In the last century, more and more research has been put into plasma polymers. Many different deposition systems have been developed. [1, 2] Shi F. F. broadly classified them into internal electrode...... plasma. In this study, we are presenting the surface modification"pf polymers by plasma polymerization using Softplasma™. Softplasma™ can be used for two major types of polymerization: polymerization of vinyl monomers, where plasma acts as initiator; chemical vapour deposition, where plasma acts...

  19. Plasma engineering: a perspective

    Gralnick, S.L.

    1978-01-01

    This review paper will present the authors perspective of the field of Plasma Engineering as it has evolved over the preceding five years. This embrionic discipline has grown in that period of time to the point where it is sufficiently mature to become part of the curriculum, and a speciality within, the discipline of Nuclear Engineering. Plasma Engineering can be distinguished from the underlying science of plasma physics in that in the pursuit of the latter, our goal is the understanding of the fundamental processes governing the behavior of plasmas while the former discipline seeks the embodiment of these concepts in useful devices. Consequent to this goal, the plasma engineer, of necessity, is concerned with the interfaces between a plasma configuration and the device by which it is produced and maintained. These interface problems, often referred to as kitchen physics are multidisciplinary in nature, and their solution requires careful attention to both plasma physics and machine engineering detail

  20. Applied plasma physics

    Anon.

    1978-01-01

    Applied Plasma Physics is a major sub-organizational unit of the MFE Program. It includes Fusion Plasma Theory and Experimental Plasma Research. The Fusion Plasma Theory group has the responsibility for developing theoretical-computational models in the general areas of plasma properties, equilibrium, stability, transport, and atomic physics. This group has responsibility for giving guidance to the mirror experimental program. There is a formal division of the group into theory and computational; however, in this report the efforts of the two areas are not separated since many projects have contributions from members of both. Under the Experimental Plasma Research Program, we are developing the intense, pulsed neutral-beam source (IPINS) for the generation of a reversed-field configuration on 2XIIB. We are also studying the feasibility of utilizing certain neutron-detection techniques as plasma diagnostics in the next generation of thermonuclear experiments

  1. Metallurgical plasma torches

    Shapovalov, V.A.; Latash, Yu.V.

    2000-01-01

    The technological equipment for the plasma heating of metals, plasma melting and plasma treatment of the surface is usually developed on the basis of are plasma torches using direct or alternating current. The reasons which partly restrict the industrial application of the plasma torches are the relatively short service life of the electrode (cathode) on which the arc is supported, and the contamination of the treated metal with the products of failure of the electrode. The aim of this work was to determine the reasons for the occurrence of negative phenomena observed in the process of service of plasma torches, and propose suitable approaches to the design of metallurgical plasma torches characterised by a long service life

  2. para mejorar el %R

    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

  3. Plasmas for medicine

    von Woedtke, Th.; Reuter, S.; Masur, K.; Weltmann, K.-D.

    2013-09-01

    Plasma medicine is an innovative and emerging field combining plasma physics, life science and clinical medicine. In a more general perspective, medical application of physical plasma can be subdivided into two principal approaches. (i) “Indirect” use of plasma-based or plasma-supplemented techniques to treat surfaces, materials or devices to realize specific qualities for subsequent special medical applications, and (ii) application of physical plasma on or in the human (or animal) body to realize therapeutic effects based on direct interaction of plasma with living tissue. The field of plasma applications for the treatment of medical materials or devices is intensively researched and partially well established for several years. However, plasma medicine in the sense of its actual definition as a new field of research focuses on the use of plasma technology in the treatment of living cells, tissues, and organs. Therefore, the aim of the new research field of plasma medicine is the exploitation of a much more differentiated interaction of specific plasma components with specific structural as well as functional elements or functionalities of living cells. This interaction can possibly lead either to stimulation or inhibition of cellular function and be finally used for therapeutic purposes. During recent years a broad spectrum of different plasma sources with various names dedicated for biomedical applications has been reported. So far, research activities were mainly focused on barrier discharges and plasma jets working at atmospheric pressure. Most efforts to realize plasma application directly on or in the human (or animal) body for medical purposes is concentrated on the broad field of dermatology including wound healing, but also includes cancer treatment, endoscopy, or dentistry. Despite the fact that the field of plasma medicine is very young and until now mostly in an empirical stage of development yet, there are first indicators of its enormous

  4. Inmunopotenciadores para la acuicultura

    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.

  5. Plasma sheath in non-Maxwellian plasma

    Shimizu, Takuo; Horigome, Takashi

    1992-01-01

    Reviewing many theoretical and experimental works on the electron-energy distributions (EEDF) of various plasmas, we point out that many plasmas have EEDF of non-Maxwellian in shape. Therefore, the recent treatment of plasma sheath using the Maxwell-Boltzmann distribution approximation should be improved. To do this, we have adopted Rutcher's standard distribution as a generalized form in place of the traditional Maxwellian, and found that the minimum energy of ions entering the sheath edge (Bohm's criterion) varies largely, and have also shown the variation of Debye length with the shape of EEDF. The length is the most important parameter to proceed with more detailed analysis on plasma-sheaths, and also to control them in the future. (author)

  6. Ha vuelto para mirarnos

    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.

  7. Interfaces para control cerebral

    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...

  8. Comunicar para la salud

    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?

  9. Democracia para ciudadanos ciborgs

    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.

  10. Democracia para ciudadanos ciborgs

    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.

  11. Particle modeling of plasmas computational plasma physics

    Dawson, J.M.

    1991-01-01

    Recently, through the development of supercomputers, a powerful new method for exploring plasmas has emerged; it is computer modeling of plasmas. Such modeling can duplicate many of the complex processes that go on in a plasma and allow scientists to understand what the important processes are. It helps scientists gain an intuition about this complex state of matter. It allows scientists and engineers to explore new ideas on how to use plasma before building costly experiments; it allows them to determine if they are on the right track. It can duplicate the operation of devices and thus reduce the need to build complex and expensive devices for research and development. This is an exciting new endeavor that is in its infancy, but which can play an important role in the scientific and technological competitiveness of the US. There are a wide range of plasma models that are in use. There are particle models, fluid models, hybrid particle fluid models. These can come in many forms, such as explicit models, implicit models, reduced dimensional models, electrostatic models, magnetostatic models, electromagnetic models, and almost an endless variety of other models. Here the author will only discuss particle models. He will give a few examples of the use of such models; these will be taken from work done by the Plasma Modeling Group at UCLA because he is most familiar with work. However, it only gives a small view of the wide range of work being done around the US, or for that matter around the world

  12. Diazepam e nordiazepam em plasma: métodos de extração líquido-líquido e em fase sólida no pré-tratamento de amostras para análise cromatográfica em fase líquida Diazepam and nordiazepam in plasma: liquid-liquid and solid phase extraction in sample pre-treatment for high performance liquid chromatography analysis

    Ellen Figueiredo Freire

    2005-10-01

    Full Text Available Analysis of diazepam (DZP and its active metabolite nordiazepam (NDZP in plasma is commonly performed in clinical medicine to ensure proper therapeutic effects while minimizing the incidence of toxicity. This study aimed to optimize analytical parameters and compare two pre-treatment techniques, liquid-liquid (LLE and solid phase extraction (SPE, as well as liquid chromatographic conditions to analyze simultaneously DZP and NDZP in plasma from 20 patients treated with a daily dose of 10 mg. Both techniques showed to be well in line with the international criteria for analytical validation, which permitted to quantify DZP (66.2 - 1148.6 ng mL-1 and NDZP (138.5 - 808.6 ng mL -1 in all samples. The correlation coefficients between SPE and LLE were respectively 0.9729 for DZP and 0.9643 for NDZP.

  13. Serie: Madera para construcción Acabados para madera

    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...

  14. Magnetospheric plasma waves

    Shawhan, S.D.

    1977-01-01

    A brief history of plasma wave observations in the Earth's magnetosphere is recounted and a classification of the identified plasma wave phenomena is presented. The existence of plasma waves is discussed in terms of the characteristic frequencies of the plasma, the energetic particle populations and the proposed generation mechanisms. Examples are given for which plasmas waves have provided information about the plasma parameters and particle characteristics once a reasonable theory has been developed. Observational evidence and arguments by analogy to the observed Earth plasma wave processes are used to identify plasma waves that may be significant in other planetary magnetospheres. The similarities between the observed characteristics of the terrestrial kilometric radiation and radio bursts from Jupiter, Saturn and possibly Uranus are stressed. Important scientific problems concerning plasma wave processes in the solar system and beyond are identified and discussed. Models for solar flares, flare star radio outbursts and pulsars include elements which are also common to the models for magnetospheric radio bursts. Finally, a listing of the research and development in terms of instruments, missions, laboratory experiments, theory and computer simulations needed to make meaningful progress on the outstanding scientific problems of plasma wave research is given. (Auth.)

  15. Particle beams and plasmas

    Hofmann, A.; Messerschmid, E.; Lawson, J.D.

    1976-01-01

    These lectures present a survey of some of the concepts of plasma physics and look at some situations familiar to particle-accelerator physicists from the point of view of a plasma physicist, with the intention of helping to link together the two fields. At the outset, basic plasma concepts are presented, including definitions of a plasma, characteristic parameters, magnetic pressure and confinement. This is followed by a brief discussion on plasma kinetic theory, non-equilibrium plasma, and the temperature of moving plasmas. Examples deal with beams in the CERN Intersecting Storage Rings as well as with non-steady beams in cyclic accelerators and microwave tubes. In the final chapters, time-varying systems are considered: waves in free space and the effect of cylinder bounds, wave motion in cold stationary plasmas, and waves in plasmas with well-defined streams. The treatment throughout is informal, with emphasis on the essential physical properties of continuous beams in accelerators and storage rings in relation to the corresponding problems in plasma physics and microwave tubes. (Author)

  16. "Colaborar para Competir"

    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.

  17. Principios teatrales para docentes

    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

  18. Determinación del valor umbral de tamizaje de la glicemia en ayunas, para identificar la intolerancia a los carbohidratos, en mujeres con síndrome de ovarios poliquísticos Determination of fasting plasma glucose cut-off valuefor the identification of abnormal carbohydrate tolerance in women with polycystic ovarian syndrome

    Yai-Linn Chang; Leonardo Orozco-Saborío; Ileana Azofeifa-Hernández; Gerardo Montiel-Larios

    2012-01-01

    Objetivo: determinar el valor predictivo de la glucosa en ayunas, para identificar intolerancia a los carbohidratos en pacientes con síndrome de ovario poliquístico. Materiales y métodos: a 100 mujeres con diagnóstico de síndrome de ovario poliquístico, se les realizó una prueba de tolerancia a 75 g de glucosa. Resultados: la sensibilidad para una cifra umbral de 101 mg/dl, fue de un 41,7%, IC 95%: 23% - 63%, y la especificidad de un 92,1%, IC95 %:83% - 97%. Con un valor predictivo positivo d...

  19. Un nuevo m??todo de cromatograf??a de l??quidos de alto rendimiento y de fase inversa para la determinaci??n de flutamida en liposomas, plasma de sangre de rata y formas de dosificaci??n en comprimidos

    Umrethia, M.L.; Ghosh, P.K.; Majithiya, R.J.; Murthy, R.S.R.

    2005-01-01

    La flutamida es un antiandr??geno ampliamente utilizado en el tratamiento del c??ncer de pr??stata que afecta al nivel de ant??geno espec??fico de la pr??stata (PSA) en sangre, lo que requiere que sea estable en la sangre durante el suficiente tiempo. Se ha desarrollado una nueva forma de dosificaci??n farmac??utica, los liposomas, para mejorar la eficacia de este f??rmaco. El objeto de este estudio es desarrollar un m??todo HPLC UV para la determinaci??n de la FLT en los liposoma...

  20. Introduction to complex plasmas

    Bonitz, Michael; Ludwig, Patrick; Horing, Norman

    2010-01-01

    Complex plasmas differ from traditional plasmas in many ways: these are low-temperature high pressure systems containing nanometer to micrometer size particles which may be highly charged and strongly interacting. The particles may be chemically reacting or be in contact with solid surfaces, and the electrons may show quantum behaviour. These interesting properties have led to many applications of complex plasmas in technology, medicine and science. Yet complex plasmas are extremely complicated, both experimentally and theoretically, and require a variety of new approaches which go beyond standard plasma physics courses. This book fills this gap presenting an introduction to theory, experiment and computer simulation in this field. Based on tutorial lectures at a very successful recent Summer Institute, the presentation is ideally suited for graduate students, plasma physicists and experienced undergraduates. (orig.)

  1. Introduction to Complex Plasmas

    Bonitz, Michael; Ludwig, Patrick

    2010-01-01

    Complex plasmas differ from traditional plasmas in many ways: these are low-temperature high pressure systems containing nanometer to micrometer size particles which may be highly charged and strongly interacting. The particles may be chemically reacting or be in contact with solid surfaces, and the electrons may show quantum behaviour. These interesting properties have led to many applications of complex plasmas in technology, medicine and science. Yet complex plasmas are extremely complicated, both experimentally and theoretically, and require a variety of new approaches which go beyond standard plasma physics courses. This book fills this gap presenting an introduction to theory, experiment and computer simulation in this field. Based on tutorial lectures at a very successful recent Summer Institute, the presentation is ideally suited for graduate students, plasma physicists and experienced undergraduates.

  2. Nonideal plasmas - experimental research

    Guenther, K.; Hess, H.; Radtke, R.

    1986-01-01

    The investigation of nonideal, strongly coupled, or non-Debye plasmas is a new field of the well-known arc plasma physics. The increased pressure and density cause different behaviour of the dense plasma. The paper surveys the main differences between the nonideal and the usual arc plasmas. The electrical conductivity, continuum radiation absorption coefficient, shift and broadening of spectral lines, and plasma phase transition are discussed. The problems of generation and diagnostics of nonideal plasmas are also described. Finally, the importance of the topic is underlined: possible applications in astrophysics and in different fields of technology: light sources, MHD generators, circuit breakers, laser mirrors and shutters, high temperature gas-phase fission reactors, material treatment and laser fusion are mentioned. (D.Gy.)

  3. Thermal plasma waste treatment

    Heberlein, Joachim; Murphy, Anthony B

    2008-01-01

    Plasma waste treatment has over the past decade become a more prominent technology because of the increasing problems with waste disposal and because of the realization of opportunities to generate valuable co-products. Plasma vitrification of hazardous slags has been a commercial technology for several years, and volume reduction of hazardous wastes using plasma processes is increasingly being used. Plasma gasification of wastes with low negative values has attracted interest as a source of energy and spawned process developments for treatment of even municipal solid wastes. Numerous technologies and approaches exist for plasma treatment of wastes. This review summarizes the approaches that have been developed, presents some of the basic physical principles, provides details of some specific processes and considers the advantages and disadvantages of thermal plasmas in waste treatment applications. (topical review)

  4. Binary recombination of para- and ortho-H3+ with electrons at low temperatures.

    Dohnal, P; Hejduk, M; Varju, J; Rubovic, P; Roucka, S; Kotrík, T; Plasil, R; Johnsen, R; Glosík, J

    2012-11-13

    Results of an experimental study of binary recombination of para- and ortho-H(3)(+) ions with electrons are presented. Near-infrared cavity-ring-down absorption spectroscopy was used to probe the lowest rotational states of H(3)(+) ions in the temperature range of 77-200 K in an H(3)(+)-dominated afterglow plasma. By changing the para/ortho abundance ratio, we were able to obtain the binary recombination rate coefficients for pure and para-H(3)(+) and ortho-H(3)(+). The results are in good agreement with previous theoretical predictions.

  5. Compression of toroidal plasma by imploding plasma-liner

    Ikuta, Kazunari.

    1979-07-01

    A new concept of compressing a plasma in a closed magnetic configuration by a version of liner implosion flux compression technique is considered. The liner consists of a dense plasma cylinder, i.e. the plasma-liner. Maximum compression ratio of toroidal plasma is determined just by the initial density ratio of the toroidal plasma to the liner plasma because of the Rayleigh-Taylor instability. A start-up senario of plasma-liner is also proposed with a possible application of this concept to the creation of a burning plasma in reversed field configurations, i.e. burning plasma vortex. (author)

  6. Space plasmas 2

    Frankel, N.E.; Hines, K.C.; Kowalenko, V.

    1981-01-01

    The longitudinal dielectric response of an ultra-degenerate relativistic plasma composed of electrons and positrons is considered. The relativistic Hartree self-consistent field method is used to investigate the dispersion relations and damping parameters of such a plasma in the presence of a magnetic field. These properties must be studied in the various regimes appropriate for a relativistic plasma as detailed by Tsytovich and Jancovici

  7. Plasma polarization spectroscopy

    Iwamae, Atsushi; Horimoto, Yasuhiro; Fujimoto, Takashi; Hasegawa, Noboru; Sukegawa, Kouta; Kawachi, Tetsuya

    2005-01-01

    The electron velocity distribution function (EVDF) in plasma can be anisotropic in laser-produced plasmas. We have developed a new technique to evaluate the polarization degree of the emission lines in the extreme vacuum ultra violet wavelength region. The polarization of the emission lines and the continuums from the lithium-like nitrogen and from helium- and hydrogen-like carbon in recombining plasma is evaluated. Particle simulation in the velocity space gives the time scale for relaxation of anisotropic EVDFs. (author)

  8. Plasma nitriding of steels

    Aghajani, Hossein

    2017-01-01

    This book focuses on the effect of plasma nitriding on the properties of steels. Parameters of different grades of steels are considered, such as structural and constructional steels, stainless steels and tools steels. The reader will find within the text an introduction to nitriding treatment, the basis of plasma and its roll in nitriding. The authors also address the advantages and disadvantages of plasma nitriding in comparison with other nitriding methods. .

  9. Cyclotron waves in plasma

    Lominadse, D.G.

    1975-01-01

    The book deals with fundamental physical concepts of the theory of cyclotron waves and cyclotron instabilities conditioned by the presence in plasma of direct or alternating electric currents passing in it perpendicularily to a magnetic field. A great variety of problems is considered connected with the linear theory of cyclotron oscillations in equilibrium and electron plasma of metals and semiconductors. Parametric excitations of electron cyclotron oscillations of plasma in an alternating electric field are studied. Particular attention is paid to the investigation of plasma turbulence arising as a result of development of cyclotron instabilities. Experimental data are discussed and compared with theoretical results

  10. Princeton Plasma Physics Laboratory

    1990-01-01

    This report discusses the following topics: principal parameters achieved in experimental devices fiscal year 1990; tokamak fusion test reactor; compact ignition tokamak; Princeton beta experiment- modification; current drive experiment-upgrade; international collaboration; x-ray laser studies; spacecraft glow experiment; plasma processing: deposition and etching of thin films; theoretical studies; tokamak modeling; international thermonuclear experimental reactor; engineering department; project planning and safety office; quality assurance and reliability; technology transfer; administrative operations; PPPL patent invention disclosures for fiscal year 1990; graduate education; plasma physics; graduate education: plasma science and technology; science education program; and Princeton Plasma Physics Laboratory reports fiscal year 1990.

  11. Princeton Plasma Physics Laboratory

    1990-01-01

    This report discusses the following topics: principal parameters achieved in experimental devices fiscal year 1990; tokamak fusion test reactor; compact ignition tokamak; Princeton beta experiment- modification; current drive experiment-upgrade; international collaboration; x-ray laser studies; spacecraft glow experiment; plasma processing: deposition and etching of thin films; theoretical studies; tokamak modeling; international thermonuclear experimental reactor; engineering department; project planning and safety office; quality assurance and reliability; technology transfer; administrative operations; PPPL patent invention disclosures for fiscal year 1990; graduate education; plasma physics; graduate education: plasma science and technology; science education program; and Princeton Plasma Physics Laboratory reports fiscal year 1990

  12. Plasma processing for VLSI

    Einspruch, Norman G

    1984-01-01

    VLSI Electronics: Microstructure Science, Volume 8: Plasma Processing for VLSI (Very Large Scale Integration) discusses the utilization of plasmas for general semiconductor processing. It also includes expositions on advanced deposition of materials for metallization, lithographic methods that use plasmas as exposure sources and for multiple resist patterning, and device structures made possible by anisotropic etching.This volume is divided into four sections. It begins with the history of plasma processing, a discussion of some of the early developments and trends for VLSI. The second section

  13. Nonlinear Physics of Plasmas

    Kono, Mitsuo

    2010-01-01

    A nonlinearity is one of the most important notions in modern physics. A plasma is rich in nonlinearities and provides a variety of behaviors inherent to instabilities, coherent wave structures and turbulence. The book covers the basic concepts and mathematical methods, necessary to comprehend nonlinear problems widely encountered in contemporary plasmas, but also in other fields of physics and current research on self-organized structures and magnetized plasma turbulence. The analyses make use of strongly nonlinear models solved by analytical techniques backed by extensive simulations and available experiments. The text is written for senior undergraduates, graduate students, lecturers and researchers in laboratory, space and fusion plasmas.

  14. The plasma universe

    Faelthammar, C.G.

    1989-12-01

    The term 'Plasma Universe', coined by Hannes Alfven, emphasices the fact that plasma phenomena discovered in the laboratory and in accessible regions of space. must be important also in the rest of the universe, which consists almost entirely of matter in the plasma state. Relevant aspect of this concept will be discussed. They include the response of the plasma to electric currents, the support of magnetic-field aligned electric fields, violation of the frozen-field condition, rapid release of magnetically stored energy, acceleration of charged particles, chemical separation, and filamentary and cellular structures. (authors)

  15. Bases para proyectiles dirigidos

    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.

  16. Registrar para avanzar

    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.

  17. The plasma physics of plasma processing

    Shohet, L.

    1991-01-01

    Plasma processing is used for producing new materials with unusual and superior properties, for developing new chemical compounds and processes, for machining, and for altering and refining materials and surfaces. It has direct applications to semiconductor fabrication, materials synthesis, welding, lighting, polymers, anti-corrosion coatings, machine tools, metallurgy, electrical and electronics devices, hazardous waste removal, high performance ceramics, and many other items in both high-technology and the more traditional industries. Plasma processing takes on a wide variety of apparently different forms in industry, but the techniques share many common characteristics and problems. Control of the generation and flux of ions, electrons and free radicals in the plasma and their incidence on a surface is vital. Diagnostics, sensors, modeling techniques, and associated statistical methods are needed. However, without an in-depth understanding of the variety of phenomena taking place and their application to the industrial environment, advances in this technology, and its efficient use, will occur at a diminishing rate

  18. Plasma Physics An Introduction to Laboratory, Space, and Fusion Plasmas

    Piel, Alexander

    2010-01-01

    Plasma Physics gives a comprehensive introduction to the basic processes in plasmas and demonstrates that the same fundamental concepts describe cold gas-discharge plasmas, space plasmas, and hot fusion plasmas. Starting from particle drifts in magnetic fields, the principles of magnetic confinement fusion are explained and compared with laser fusion. Collective processes are discussed in terms of plasma waves and instabilities. The concepts of plasma description by magnetohydrodynamics, kinetic theory, and particle simulation are stepwise introduced. Space charge effects in sheath regions, double layers and plasma diodes are given the necessary attention. The new fundamental mechanisms of dusty plasmas are explored and integrated into the framework of conventional plasmas. The book concludes with a brief introduction to plasma discharges. Written by an internationally renowned researcher in experimental plasma physics, the text keeps the mathematical apparatus simple and emphasizes the underlying concepts. T...

  19. The para-petroleum industry

    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.)

  20. Método de eliminación de trihalometanos y/o contaminantes emergentes mediante plasma

    Erra Serrabasa, Pilar; Jover Comas, Eric; Molina Mansilla, Ricardo; Bertrán Serra, Enric; Bayona Termens, Josep María; Reyes Contreras, Carolina

    2009-01-01

    Método de eliminación de trihalometanos y/o contaminantes emergentes mediante plasma. Se describe un método de eliminación de trihalometanos y contaminantes refractarios en medios acuosos mediante la aplicación directa de plasma para conseguir la degradación de los compuestos contaminantes presentes en el agua.

  1. EDITORIAL: Plasma jets and plasma bullets Plasma jets and plasma bullets

    Kong, M. G.; Ganguly, B. N.; Hicks, R. F.

    2012-06-01

    Plasma plumes, or plasma jets, belong to a large family of gas discharges whereby the discharge plasma is extended beyond the plasma generation region into the surrounding ambience, either by a field (e.g. electromagnetic, convective gas flow, or shock wave) or a gradient of a directionless physical quantity (e.g. particle density, pressure, or temperature). This physical extension of a plasma plume gives rise to a strong interaction with its surrounding environment, and the interaction alters the properties of both the plasma and the environment, often in a nonlinear and dynamic fashion. The plasma is therefore not confined by defined physical walls, thus extending opportunities for material treatment applications as well as bringing in new challenges in science and technology associated with complex open-boundary problems. Some of the most common examples may be found in dense plasmas with very high dissipation of externally supplied energy (e.g. in electrical, optical or thermal forms) and often in or close to thermal equilibrium. For these dense plasmas, their characteristics are determined predominantly by strong physical forces of different fields, such as electrical, magnetic, thermal, shock wave, and their nonlinear interactions [1]. Common to these dense plasma plumes are significant macroscopic plasma movement and considerable decomposition of solid materials (e.g. vaporization). Their applications are numerous and include detection of elemental traces, synthesis of high-temperature materials and welding, laser--plasma interactions, and relativistic jets in particle accelerators and in space [2]-[4]. Scientific challenges in the understanding of plasma jets are exciting and multidisciplinary, involving interweaving transitions of all four states of matter, and their technological applications are wide-ranging and growing rapidly. Using the Web of Science database, a search for journal papers on non-fusion plasma jets reveals that a long initial phase up

  2. Geospace Plasma Dynamics

    2013-05-22

    perturbations. High-speed solar wind streams cause recurrent geomagnetic activity and ionospheric disturbances. In [5], we analyze the equatorial...over eight successive orbits (~12 hours). A clear pre- reversal enhancement of upward plasma drift occurred between 18:00 and 19:00 LT when plasma

  3. Introduction to Plasma Spectroscopy

    Kunze, H-J

    2009-01-01

    Based on lectures given at the Ruhr-University of Bochum for graduate students and postgraduates starting in plasma physics as well as from low- to high-density hot plasmas, this book introduces basic ideas and fundamental concepts and typical instrumentation from the X-ray to the infrared spectral regions

  4. General Relativistic Plasma Dynamics

    Moortgat, J.B.

    2006-01-01

    In this thesis I discuss the importance of general relativity on plasma physics in several astrophysical and cosmological contexts. The first chapters show how gravitational waves can excite all three fundamental low frequency magnetohydrodynamic plasma modes, the Alfven, slow and fast

  5. Atoms in dense plasmas

    More, R.M.

    1986-01-01

    Recent experiments with high-power pulsed lasers have strongly encouraged the development of improved theoretical understanding of highly charged ions in a dense plasma environment. This work examines the theory of dense plasmas with emphasis on general rules which govern matter at extreme high temperature and density. 106 refs., 23 figs

  6. Waves in unmagnetized plasma

    Lambert, A.J.D.

    1979-01-01

    A review of linear and weakly non-linear theory of electron waves, ion waves and electromagnetic waves in plasmas is presented. The author restricts the discussion to an infinitely extended, homogeneous and isotropic plasma, not affected by external fields and described by Vlasov's and Maxwell's equations. (Auth.)

  7. Plasma processing and chemistry

    Schram, D.C.

    2002-01-01

    A review. Plasma deposition and plasma conversion can be characterized by five steps: prodn. by ionization, transfer of chem. to precursors, transport of radicals to the surface, surface interactions with deposition, recirculation and generation of new monomers. For very fast deposition, large flows

  8. Plasma technology directory

    Ward, P.P.; Dybwad, G.L.

    1995-01-01

    The Plasma Technology Directory has two main goals: (1) promote, coordinate, and share plasma technology experience and equipment within the Department of Energy; and (2) facilitate technology transfer to the commercial sector where appropriate. Personnel are averaged first by Laboratory and next by technology area. The technology areas are accelerators, cleaning and etching deposition, diagnostics, and modeling

  9. Atoms in dense plasmas

    More, R.M.

    1986-01-01

    Recent experiments with high-power pulsed lasers have strongly encouraged the development of improved theoretical understanding of highly charged ions in a dense plasma environment. This work examines the theory of dense plasmas with emphasis on general rules which govern matter at extreme high temperature and density. 106 refs., 23 figs.

  10. Microwave plasma mode conversion

    Torres, H.S.; Sakanaka, P.H.; Villarroel, C.H.

    1985-01-01

    The behavior of hot electrons during the process of laser-produced plasma is studied. The basic equations of mode conversion from electromagnetic waves to electrostatic waves are presented. It is shown by mode conversion, that, the resonant absorption and parametric instabilities appear simultaneously, but in different plasma regions. (M.C.K.) [pt

  11. Polychromatic holographic plasma diagnostics

    Zhiglinskij, A.G.; Morozov, A.O.

    1992-01-01

    Review of holographic interferometry properties is performed and advantages of this method by plasma diagnostics are indicated. Main results obtained by the method of holographic interferometry in studies of various-type plasmas are considered. Special attention is paid to multiwave plasma diagnostics, the necessity of which is related as a rule to multicomponent composition of plasma. The eight laser and gas-discharge sources and holographic schemes, which make it possible to realize plasma polychromatic and holographic interferometry, are considered. The advantages of the method are demonstrated by examples of polychromatic holographic diagnostics of arc discharge and discharge in a hollow cathode. Review of theoretical works determining the applicability area of resonance polychromatic interferometry is carried out

  12. Chaotic phenomena in plasmas

    Kawai, Y.

    1991-08-01

    It has recently been recognized that the research on various aspects of chaotic dynamics grows rapidly as one of some areas in nonlinear science. On the other hands, the plasma has long been called a treasure-house of nonlinear phenomena, so it is easy to imagine that the plasma is abundant in chaotic phenomena. In fact, the research on plasma chaos is going on, such as the research on the stochastic magnetic field and the chaotic orbit in the toroidal helical system, as well as the research in other experiments. To review the present status of the research on plasma chaos and to make clear the basic common physics, a working group was organized in 1990 as a collaboration research of National Institute for Fusion Science. This is the report on its activity in 1990, with a stress on experimental data obtained in basic plasma experiments and RFP, and on the relaxed theories and computer simulations. (author)

  13. Plasma based accelerators

    Caldwell, Allen [Max-Planck-Institut fuer Physik, Muenchen (Germany)

    2015-05-01

    The concept of laser-induced plasma wakefields as a technique to accelerate charged particles was introduced 35 years ago as a means to go beyond the accelerating gradients possible with metallic cavities supporting radio frequency electromagnetic fields. Significant developments in laser technology have made possible the pulse intensity needed to realize this concept, and rapid progress is now underway in the realization of laser-driven plasma wakefield acceleration. It has also been realized that similar accelerating gradients can be produced by particle beams propagating in plasmas, and experimental programs have also been undertaken to study this possibility. Positive results have been achieved with electron-driven plasma wakefields, and a demonstration experiment with proton-driven wakefields is under construction at CERN. The concepts behind these different schemes and their pros and cons are described, as well as the experimental results achieved. An outlook for future practical uses of plasma based accelerators will also be given.

  14. Solar system plasma waves

    Gurnett, Donald A.

    1995-01-01

    An overview is given of spacecraft observations of plasma waves in the solar system. In situ measurements of plasma phenomena have now been obtained at all of the planets except Mercury and Pluto, and in the interplanetary medium at heliocentric radial distances ranging from 0.29 to 58 AU. To illustrate the range of phenomena involved, we discuss plasma waves in three regions of physical interest: (1) planetary radiation belts, (2) planetary auroral acceleration regions and (3) the solar wind. In each region we describe examples of plasma waves that are of some importance, either due to the role they play in determining the physical properties of the plasma, or to the unique mechanism involved in their generation.

  15. Plasma-material interactions

    Wilson, K.L.

    1984-01-01

    Plasma-interactive components must be resistant to erosion processes, efficient in heat removal, and effective in minimizing tritium inventory and permeation. As long as plasma edge temperatures are 50 eV, no one material can satisfy the diverse requirements imposed by these plasma materials interactions. The only solution is the design of duplex, or even more complicated, structures. The material that faces the plasma should be low atomic number, with acceptable erosion and evaporation characteristics. The substrate material must have high thermal conductivity for heat removal. Finally, materials must be selected judiciously for tritium compatibility. In conclusion, materials play a critical role in the achievement of safe and economical magnetic fusion energy. Improvements in materials have already led to many advances in present day device operation, but additional innovative materials solutions are required for the critical plasma materials interaction issues in future power reactors

  16. SUPERFAST THERMALIZATION OF PLASMA

    Chang, C.C.

    1962-06-12

    A method is given for the superfast thermalization of plasma by shock conversion of the kinetic energy stored in rotating plasma rings or plasmoids colliding at near supersonic speeds in a containment field to heat energy in the resultant confined plasma mass. The method includes means for generating rotating plasmoids at the opposite ends of a Pyrotron or Astron containment field. The plasmoids are magnetically accelerated towards each other into the opposite ends of time containment field. During acceleration of the plasmoids toward the center of the containment field, the intensity of the field is sequentially increased to adiabatically compress the plasmoids and increase the plasma energy. The plasmoids hence collide with a violent shock at the eenter of the containment field, causing the substantial kinetic energy stored in the plasmoids to be converted to heat in the resultant plasma mass. (AEC)

  17. Antimatter plasmas and antihydrogen

    Greaves, R.G.; Surko, C.M.

    1997-01-01

    Recent successes in confining antimatter in the form of positron and antiproton plasmas have created new scientific and technological opportunities. Plasma techniques have been the cornerstone of experimental work in this area, and this is likely to be true for the foreseeable future. Work by a number of groups on trapping antimatter plasmas is summarized, and an overview of the promises and challenges in this field is presented. Topics relating to positron plasmas include the use of positrons to study the unique properties of electron endash positron plasmas, the interaction between positrons and ordinary matter, and the laboratory modeling of positron-annihilation processes in interstellar media. The availability of cold, trapped antiprotons and positrons makes possible the production of neutral antimatter in the form of antihydrogen. This is expected to enable precise comparisons of the properties of matter and antimatter, including tests of fundamental symmetries and the measurement of the interaction of antimatter with gravity. copyright 1997 American Institute of Physics

  18. A new large-scale plasma source with plasma cathode

    Yamauchi, K.; Hirokawa, K.; Suzuki, H.; Satake, T.

    1996-01-01

    A new large-scale plasma source (200 mm diameter) with a plasma cathode has been investigated. The plasma has a good spatial uniformity, operates at low electron temperature, and is highly ionized under relatively low gas pressure of about 10 -4 Torr. The plasma source consists of a plasma chamber and a plasma cathode generator. The plasma chamber has an anode which is 200 mm in diameter, 150 mm in length, is made of 304 stainless steel, and acts as a plasma expansion cup. A filament-cathode-like plasma ''plasma cathode'' is placed on the central axis of this source. To improve the plasma spatial uniformity in the plasma chamber, a disk-shaped, floating electrode is placed between the plasma chamber and the plasma cathode. The 200 mm diameter plasma is measure by using Langmuir probes. As a result, the discharge voltage is relatively low (30-120 V), the plasma space potential is almost equal to the discharge voltage and can be easily controlled, the electron temperature is several electron volts, the plasma density is about 10 10 cm -3 , and the plasma density is about 10% variance in over a 100 mm diameter. (Author)

  19. Plasma sheath criterion in thermal electronegative plasmas

    Ghomi, Hamid; Khoramabadi, Mansour; Ghorannevis, Mahmod; Shukla, Padma Kant

    2010-01-01

    The sheath formation criterion in electronegative plasma is examined. By using a multifluid model, it is shown that in a collisional sheath there will be upper as well as lower limits for the sheath velocity criterion. However, the parameters of the negative ions only affect the lower limit.

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

    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

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

    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.

  2. Proceedings of the thirty second national symposium on plasma science and technology: plasma for societal benefits: book of abstracts

    Dave, Sandhya; Shravan Kumar, S.; Vijayakumaran; Singh, Raj; Awasthi, L.M.

    2017-01-01

    This symposium covers topics on: basic plasma, computer modelling for plasma, exotic plasma, industrial plasma, laser plasma theory, nuclear fusion, plasma diagnostics, laser plasma, plasma processing, pulsed power, space and astrophysical plasma. Papers relevant to INIS are indexed separately

  3. Para compreender a ciberliteratura

    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.

  4. para promover la salud

    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.

  5. Plasma rico en plaquetas en pacientes con gonartrosis

    Álvarez López, Alejandro; Ortega González, Carlos; García Lorenzo, Yenima; Arias Sifontes, Joanka; Ruiz de Villa Suárez, Abel

    2013-01-01

    Fundamento: la aplicación del plasma rico en plaquetas se ha convertido en una modalidad de tratamiento para pacientes con gonartrosis, tanto de forma aislada como en combinación con otros procedimientos. Objetivo: actualizar al personal médico sobre aspectos esenciales relacionados con la aplicación del plasma rico en plaquetas en pacientes con gonartrosis. Método: se realizó una revisión bibliográfica de un total de 300 artículos originales publicados en Pubmed, Hinari y Medline, mediante e...

  6. Plasma physics an introduction to laboratory, space, and fusion plasmas

    Piel, Alexander

    2017-01-01

    The enlarged new edition of this textbook provides a comprehensive introduction to the basic processes in plasmas and demonstrates that the same fundamental concepts describe cold gas-discharge plasmas, space plasmas, and hot fusion plasmas. Starting from particle drifts in magnetic fields, the principles of magnetic confinement fusion are explained and compared with laser fusion. Collective processes are discussed in terms of plasma waves and instabilities. The concepts of plasma description by magnetohydrodynamics, kinetic theory, and particle simulation are stepwise introduced. Space charge effects in sheath regions, double layers and plasma diodes are given the necessary attention. The novel fundamental mechanisms of dusty plasmas are explored and integrated into the framework of conventional plasmas. The book concludes with a concise description of modern plasma discharges. Written by an internationally renowned researcher in experimental plasma physics, the text keeps the mathematical apparatus simple a...

  7. Waves in Space Plasmas Program

    Fredricks, R. W.; Taylor, W. W. L.

    1981-01-01

    The Waves in Space Plasmas (WISP) program is a joint international effort involving instrumentation to be designed and fabricated by funding from NASA and the National Research Council of Canada. The instrumentation, with a tentatively planned payload for 1986, can be used to perturb the plasma with radio waves to solve problems in ionospheric, atmospheric, magnetospheric, and plasma physics. Among the ionospheric and plasma phenomena to be investigated using WISP instrumentation are VLF wave-particle interactions; ELF/VLF propagation; traveling ionospheric disturbances and gravity wave coupling; equatorial plasma bubble phenomena; plasma wave physics such as mode-coupling, dispersion, and instabilities; and plasma physics of the antenna-plasma interactions.

  8. Waves in Space Plasmas Program

    Fredricks, R.W.; Taylor, W.W.L.

    1981-01-01

    The Waves in Space Plasmas (WISP) program is a joint international effort involving instrumentation to be designed and fabricated by funding from NASA and the National Research Council of Canada. The instrumentation, with a tentatively planned payload for 1986, can be used to perturb the plasma with radio waves to solve problems in ionospheric, atmospheric, magnetospheric, and plasma physics. Among the ionospheric and plasma phenomena to be investigated using WISP instrumentation are VLF wave-particle interactions, ELF/VLF propagation, traveling ionospheric disturbances and gravity wave coupling, equatorial plasma bubble phenomena, plasma wave physics such as mode-coupling, dispersion, and instabilities, and plasma physics of the antenna-plasma interactions

  9. Para-equilibrium phase diagrams

    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

  10. Marcadores para la Realidad Aumentada para fines educativos

    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.

  11. Influence of plasma density and plasma sheath dynamics on the ion implantation by plasma immersion technique

    Ensinger, Wolfgang

    1996-01-01

    Influence of plasma density and plasma sheath dynamics on the ion implantation by plasma immersion technique / B. Rauschenbach ... - In: Nuclear instruments and methods in physics research. B. 113. 1996. S. 266-269

  12. Instabilities in inhomogeneous plasma

    Mikhailovsky, A.B.

    1983-01-01

    The plasma inhomogeneity across the magnetic field causes a wide class of instabilities which are called instabilities of an inhomogeneous plasma or gradient instabilities. The instabilities that can be studied in the approximation of a magnetic field with parallel straight field lines are treated first, followed by a discussion of the influence of shear on these instabilities. The instabilities of a weakly inhomogeneous plasma with the Maxwellian velocity distribution of particles caused by the density and temperature gradients are often called drift instabilities, and the corresponding types of perturbations are the drift waves. An elementary theory of drift instabilities is presented, based on the simplest equations of motion of particles in the field of low-frequency and long-wavelength perturbations. Following that is a more complete theory of inhomogeneous collisionless plasma instabilities which uses the permittivity tensor and, in the case of electrostatic perturbations, the scalar of permittivity. The results are used to study the instabilities of a strongly inhomogeneous plasma. The instabilities of a plasma in crossed fields are discussed and the electromagnetic instabilities of plasma with finite and high pressure are described. (Auth.)

  13. High energy plasma accelerators

    Tajima, T.

    1985-05-01

    Colinear intense laser beams ω 0 , kappa 0 and ω 1 , kappa 1 shone on a plasma with frequency separation equal to the electron plasma frequency ω/sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ω/sub pe//e of the order of 1GeV/cm for a plasma density of 10 18 cm -3 through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed

  14. Plasma Science Committee (PLSC)

    1990-01-01

    The Plasma Science Committee (PLSC) is a standing committee under the auspices of the Board on Physics and Astronomy, Commission on Physical Sciences, Mathematics, and Applications of the National Academy of Sciences--National Research Council. Plasma sciences represent a broad and diverse field. The PLSC has accepted the responsibility of monitoring the continuing development and assessing the general health of the field as whole. Although select advisory bodies have been created to address specific issues that affect plasma science, such as the Fusion Policy Advisory Committee (FPAC), the PLSC provides a focus for the plasma science community that is unique and essential. The membership of the PLSC is drawn from research laboratories in universities, industry, and government. Areas of expertise on the committee include accelerators and beams, space physics, astrophysics, computational physics and applied mathematics, fusion plasmas, fundamental experiments and theory, radiation sources, low temperature plasmas, and plasma-surface interactions. The PLSC is well prepared to respond to requests for studies on specific issues. This report discusses ion of the PLSC work

  15. Algoritmos para problemas de empacotamento

    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...

  16. Electromagnetic separator of plasma

    Gasilin, V.V.; Nezovibatko, Yu.N.; Poklepach, G.S.; Shvets, O.M.; Taran, V.S.; Tereshin, V.I.

    2005-01-01

    The progress in the widespread utilization of the PVD methods is determined in many respects by the plasma quality and, therefore, the necessity of an application of plasma separators, in particular magnetic separators. One needs to note that traditional magnetic separators have a number of problems their using, namely their unwieldiness, the presence of the isolated cameras and so on. We have proposed, manufactured and investigated the simple separator of plasma that doesn't require using additional cameras. As a source of metallic plasma the standard cathode vaporizer in the installation 'BULAT 6' was in use. Plasma stream from the cathode flowed through the not protected by isolation spiral solenoid. The solenoid input (from the cathode side) was under floating potential. The solenoid output was connected to the autonomous power supply system. The solenoid was prepared with stride winding and 90 degree turn. The solenoid current was 20-90 A and the solenoid voltage with respect to the vessel (earth) was +15 V. In this case drifting charged particles could freely fly out from the interior solenoid region to its boundary. The glow of the turned flow of plasma was observed during the supplying of the cathode and the solenoid. Plasma flow was separated from the coils and extended along the axis of solenoid. One can assume that this device ensures radial electric with respect to the bulk of plasma (the diameter of the bulk of plasma is comparable with the cathode diameter), the toroidal magnetic field, produced by solenoid, was of an order of 20 Oe. Magnetic field strength was sufficient for the magnetization of electrons, but it was rather small for magnetizing the ions and charged micro-droplets. The experiments carried out with aluminum cathode on the deposition of coatings at the stainless steel substrate have shown the high effectiveness of this separator operation. Coatings without droplets were obtained also on the glass substrate with HF- displacement

  17. The expanding plasma jet

    Sanden, M.C.M. van den.

    1991-01-01

    This thesis concerns the fundamental aspects of an argon plasma expanding from a cascaded arc. This type of plasma is not only used for fundamental research but also for technologically orientated research on plasma deposition and plasma sources. The important characteristics of the plasma are a strong supersonic expansion in which the neutral particle and ion densities decrease three orders of magnitude, followed by a stationary shock front. After the shock front the plasma expands further subsonically. A part of this thesis is devoted to the discussion of a newly constructed combined Thomson-Rayleigh scattering set up. With this set up the electron density, the electron temperature and the neutral particle density are measured locally in the plasma for different conditions. In the analysis of the measured spectra weak coherent effects and the measured apparatus profile are included. The inaccuracies are small, ranging from 1 to 4 percent for the electron density and 2 to 6 percent for the electron temperature, depending on the plasma conditions. The inaccuracy of the neutral particle density determination is larger and ranges from 10 to 50 percent. The detection limits for the electron and neutral particle density are 7.10 17 m -3 and 1.10 20 m -3 respectively. A side path in this thesis is the derivation of the Saha equation for a two-temperature plasma. The reason for this derivation was the dispute in the literature about the correct form of this equation. In this thesis it is shown, from the correct extension of the second law of thermodynamics and from the non-equilibrium formalism of Zubarev, That in the limit of m e /m h ->0 the generalized Saha equation depends on the electron temperature only. (author). 221 refs.; 54 figs.; 13 tabs

  18. Transport barriers in plasmas

    Caldas, I L; Szezech, J D Jr; Kroetz, T; Marcus, F A; Roberto, M; Viana, R L; Lopes, S R

    2012-01-01

    We discuss the creation of transport barriers in magnetically confined plasmas with non monotonic equilibrium radial profiles. These barriers reduce the transport in the shearless region (i.e., where the twist condition does not hold). For the chaotic motion of particles in an equilibrium electric field with a nonmonotonic radial profile, perturbed by electrostatic waves, we show that a nontwist transport barrier can be created in the plasma by modifying the electric field radial profile. We also show non twist barriers in chaotic magnetic field line transport in the plasma near to the tokamak wall with resonant modes due to electric currents in external coils.

  19. Radioimmunoassay of plasma progesterone

    Langer, L; Veleminsky, J [Institute of Clinical Endocrinology, Lubochna (Czechoslovakia); Hampl, R; Starka, L [Vyzkumny Ustav Endokrinologicky, Prague (Czechoslovakia); Holan, J [Comenius Univ., School of Medicine, Martin (Czechoslovakia). Dept. of Physics and Nuclear Medicine

    1978-06-30

    A simple modification of plasma progesterone radioimmunoassay is described. 11..cap alpha..-Hydroxyprogesterone hemisuccinate - BSA conjugate was used as an immunogen. (1,2,6,7-H-3) Progesterone specific radioactivity 82 Ci.mmol/sup -1/ was purchased from Radiochemical Centre Amersham (England). The method has been applied for the analysis of more than 2000 plasma samples. The typical fluctuation of progesterone in plasma during the menstrual cycle, using data obtained with this method is illustrated. The reliability criteria of the method are given.

  20. Unexpected high plasma cobalamin

    Arendt, Johan F B; Nexo, Ebba

    2013-01-01

    It is well-established that more than 8% of patients examined for vitamin B12 deficiency unexpectedly have increased plasma levels of the vitamin, but so far there are no guidelines for the clinical interpretation of such findings. In this review, we summarise known associations between high plasma...... cobalamin binding proteins, transcobalamin and haptocorrin. Based on current knowledge, we suggest a strategy for the clinical interpretation of unexpected high plasma cobalamin. Since a number of the associated diseases are critical and life-threatening, the strategy promotes the concept of 'think...

  1. Ambipolar diffusion in plasma

    Silva, T.L. da.

    1987-01-01

    Is this thesis, a numerical method for the solution of the linear diffusion equation for a plasma containing two types of ions, with the possibility of charge exchange, has been developed. It has been shown that the decay time of the electron and ion densities is much smaller than that in a plasma containing only a single type of ion. A non-linear diffusion equation, which includes the effects of an external electric field varying linearly in time, to describe a slightly ionized plasma has also been developed. It has been verified that the decay of the electron density in the presence of such an electric field is very slow. (author)

  2. Nonequilibrium Phenomena in Plasmas

    Sharma, A Surjalal

    2005-01-01

    The complexity of plasmas arises mainly from their inherent nonlinearity and far from equilibrium nature. The nonequilibrium behavior of plasmas is evident in the natural settings, for example, in the Earth's magnetosphere. Similarly, laboratory plasmas such as fusion bottles also have their fair share of complex behavior. Nonequilibrium phenomena are intimately connected with statistical dynamics and form one of the growing research areas in modern nonlinear physics. These studies encompass the ideas of self-organization, phase transition, critical phenomena, self-organized criticality and turbulence. This book presents studies of complexity in the context of nonequilibrium phenomena using theory, modeling, simulations, and experiments, both in the laboratory and in nature.

  3. Computing in plasma physics

    Nuehrenberg, J.

    1986-01-01

    These proceedings contain the articles presented at the named conference. These concern numerical methods for astrophysical plasmas, the numerical simulation of reversed-field pinch dynamics, methods for numerical simulation of ideal MHD stability of axisymmetric plasmas, calculations of the resistive internal m=1 mode in tokamaks, parallel computing and multitasking, particle simulation methods in plasma physics, 2-D Lagrangian studies of symmetry and stability of laser fusion targets, computing of rf heating and current drive in tokamaks, three-dimensional free boundary calculations using a spectral Green's function method, as well as the calculation of three-dimensional MHD equilibria with islands and stochastic regions. See hints under the relevant topics. (HSI)

  4. Plasma control and utilization

    Ensley, D.L.

    1976-01-01

    A plasma is confined and heated by a microwave field resonant in a cavity excited in a combination of the TE and TM modes while responding to the resonant frequency of the cavity as the plasma dimensions change to maintain operation at resonance. The microwave field is elliptically or circularly polarized as to prevent the electromagnetic confining field from going to zero. A high Q chamber having superconductive walls is employed to minimize wall losses while providing for extraction of thermonuclear energy produced by fusion of nuclei in the plasma. 24 claims, 15 figures

  5. Radiofrequency power in plasmas

    NONE

    1995-12-31

    This document includes the various communications that were presented at the 11th topical conference on radio frequency power in plasmas which took place in Palm Springs in May 1995. It includes current diffusion studies to assess the non-inductive current deposition profiles, experiments for plasma to reach quickly an equilibrium state, and modelling of electrons in plasma. Some comparison studies also reveal the efficiency of the Quasi-Optical Grill antenna for reactor applications. Finally, a scenario for efficient mode conversion heating in the ion cyclotron range of frequency is presented. Separate abstracts were prepared for the 6 papers in this volume. (TEC).

  6. Desenvolvimento de colunas cromatográficas de meios de acesso restrito proteína-imobilizada e suas avaliações para análise de fármacos com injeção direta de plasma humano

    Lima,Virgínia Veronica de; Cassiano,Neila Maria; Cass,Quezia Bezerra

    2006-01-01

    A series of bovine serum albumin-immobilized supports have been prepared and used as restricted access media (RAM) columns. Restricted-access supports combine size-exclusion of proteins and other high-molar-mass matrix components with the simultaneous enrichment of low-molar mass analytes. These characteristics were chromatographically evaluated for the columns. The RAM-BSA (Bovine Serum Albumin) columns showed excellent performance for exclusion of human plasma protein with good retention ca...

  7. Plasma processing: Technologies and applications

    Naddaf, M.; Saloum, S.

    2005-01-01

    This study aims to present the fundamentals of physics of plasmas, methods of generation, diagnostics, and applications for processing of materials. The first chapter defines plasma in general as well as its main parameters, the most important differential equations in plasma physics, and classifies the types of plasmas. the various methods and techniques to create and sustain plasma are presented in the second chapter. Chapter 3 focuses on plasma diagnostic methods and tools. While chapter 4 deals with applications of plasma processing such as; surface modification of materials, plasma ashing and etching, plasma cutting, and the environmental applications of plasma. Plasma polymerization and its various applications have been presented in more details in the last chapter. (Author)

  8. Nuclear spin state-resolved cavity ring-down spectroscopy diagnostics of a low-temperature H3+ -dominated plasma

    Hejduk, Michal; Dohnal, Petr; Varju, Jozef; Rubovič, Peter; Plašil, Radek; Glosík, Juraj

    2012-01-01

    We have applied a continuous-wave near-infrared cavity ring-down spectroscopy method to study the parameters of a H 3 + -dominated plasma at temperatures in the range 77–200 K. We monitor populations of three rotational states of the ground vibrational state corresponding to para and ortho nuclear spin states in the discharge and the afterglow plasma in time and conclude that abundances of para and ortho states and rotational temperatures are well defined and stable. The non-trivial dependence of a relative population of para- H 3 + on a relative population of para-H 2 in a source H 2 gas is described. The results described in this paper are valuable for studies of state-selective dissociative recombination of H 3 + ions with electrons in the afterglow plasma and for the design of sources of H 3 + ions in a specific nuclear spin state. (paper)

  9. Nuclear spin state-resolved cavity ring-down spectroscopy diagnostics of a low-temperature H_3^+ -dominated plasma

    Hejduk, Michal; Dohnal, Petr; Varju, Jozef; Rubovič, Peter; Plašil, Radek; Glosík, Juraj

    2012-04-01

    We have applied a continuous-wave near-infrared cavity ring-down spectroscopy method to study the parameters of a H_3^+ -dominated plasma at temperatures in the range 77-200 K. We monitor populations of three rotational states of the ground vibrational state corresponding to para and ortho nuclear spin states in the discharge and the afterglow plasma in time and conclude that abundances of para and ortho states and rotational temperatures are well defined and stable. The non-trivial dependence of a relative population of para- H_3^+ on a relative population of para-H2 in a source H2 gas is described. The results described in this paper are valuable for studies of state-selective dissociative recombination of H_3^+ ions with electrons in the afterglow plasma and for the design of sources of H_3^+ ions in a specific nuclear spin state.

  10. Unmatter Plasma revisited

    Smarandache, Florentin

    2017-10-01

    Unmmatter Plasma is a novel form of plasma, exclusively made of matter and its antimatter counterpart. The electron-positron beam plasma was generated in the laboratory in the beginning of 2015. This experimental fact shows that unmatter, a new form of matter that is formed by matter and antimatter bind together (mathematically predicted since 2004) really exists. That is the electron-positron plasma experiment of 2015 is the experimentum crucis verifying the mathematically predicted unmatter. Unmatter is formed by combinations of matter and antimatter that bind together, or by long-range mixture of matter and antimatter forming a weakly-coupled phase. Binding and bound state means that the interaction is sufficiently strong to tie together the particles of a system, therefore hindering them from becoming free. For example, a usual liquid is a bound state of molecules, while a gas is an un-bounded where the molecules can move freely in successive collisions.

  11. Plasma concentrations of misonidazole

    Notter, G; Rylander, U; Turesson, I

    1980-10-01

    The plasma concentrations of misonidazole doses between 0.6 and 2.0 g/m/sup 2/ were analyzed in respect to the variation within the same patient and between different patients. Peak plasma levels were observed after 2 hours. The mean plasma levels of misonidazole only at 3 hours were 23.8, 47.0 and 76.5 ..mu..g/ml after misonidazole doses of 0.6, 1.2 g/m/sup 2/, respectively. The half-life of misonidazole only was found to be 8.2 hours for women and 10.5 for men. Good linearity between plasma levels and drug doses was observed after administration of different single doses to the same patient within the dose range 0.6 to 2.0 g/m/sup 2/.

  12. Plasma-surface interaction

    Kurnaev, V.A.

    1996-01-01

    The latest experimental results characterizing plasma interaction with walls in thermonuclear facilities are presented. The main attention is paid to the mode of plasma ejection from the tokamak divertor receiving elements to study the properties of the so-called gas divertor. A sharp reduction of load on the receiving plates is provided in the mode at the expense of over-radiation of a substantial share of power in a layer of peripheral removed plasma. However, the sharp reduction of load on the current-receiving plates is accompanied by an increase of the main plasma charge up to an unacceptably high level. An alternative variant of solving the problem of heat and impurity removal in the form of a concept of capillary lithium divertor is described. Besides, the latest results of experiments in simulator devices are presented. 46 refs., 15 figs

  13. Plasma formation in TBR

    Del Bosco, E.

    1981-01-01

    In this work are presented and discussed results of the formation and equilibrium of the plasma current in TBR, a small tokamak, designed and contructed at the Instituto de Fisica of Universidade de Sao Paulo. The measured breakdown curves for H 2 , A and He are compared with the predictions of a simple model with reasonable agreement. The influence of stray magnetic fields in the plasma formation is investigated and conditions are chosen to facilitate the breakdown. The time profile of loop voltage and plasma current for shots with plasma equilibrium are shown. A comparison is made between experimental results and analytical-numerical model for tokamaks discharges with ohmic heating. Reasonable agreement is obtained when Z, effective atomic number, is assumed as a parameter. (Author) [pt

  14. Vol. 6: Plasma Physics

    Sitenko, A.

    1993-01-01

    Problems of modern physics and the situation with physical research in Ukraine are considered. Programme of the conference includes scientific and general problems. Its proceeding are published in 6 volumes. The papers presented in this volume refer to plasma physics

  15. Ferroelectric Plasma Thruster

    Kovaleski, Scott D; Kemp, Mark A

    2008-01-01

    .... When radiofrequency high voltage is applied between the electrodes, through the thickness of the crystal, a combination of triple point and piezoelectric effects produce dense plasma on the crystal surface...

  16. Fizeau plasma interferometer

    Frank, A.M.

    1980-01-01

    This paper describes a technique by which the sensitivity of plasma interferometers can be increased. Stabilization and fractional fringe measurement techniques have improved to the point where additional optical sensitivity could be useful

  17. Plasma relativistic microwave electronics

    Kuzelev, M.V.; Loza, O.T.; Rukhadze, A.A.; Strelkov, P.S.; Shkvarunets, A.G.

    2001-01-01

    One formulated the principles of plasma relativistic microwave electronics based on the induced Cherenkov radiation of electromagnetic waves at interaction of a relativistic electron beam with plasma. One developed the theory of plasma relativistic generators and accelerators of microwave radiation, designed and studied the prototypes of such devices. One studied theoretically the mechanisms of radiation, calculated the efficiencies and the frequency spectra of plasma relativistic microwave generators and accelerators. The theory findings are proved by the experiment: intensity of the designed sources of microwave radiation is equal to 500 μW, the frequency of microwave radiation is increased by 7 times (from 4 up to 28 GHz), the width of radiation frequency band may vary from several up to 100%. The designed sources of microwave radiation are no else compared in the electronics [ru

  18. Plasma turbulence in tokamaks

    Caldas, Ibere L.; Heller, M.V.A.P.; Brasilio, Z.A. [Sao Paulo Univ., SP, RJ (Brazil). Inst. de Fisica

    1997-12-31

    Full text. In this work we summarize the results from experiments on electrostatic and magnetic fluctuations in tokamak plasmas. Spectral analyses show that these fluctuations are turbulent, having a broad spectrum of wavectors and a broad spectrum of frequencies at each wavector. The electrostatic turbulence induces unexpected anomalous particle transport that deteriorates the plasma confinement. The relationship of these fluctuations to the current state of plasma theory is still unclear. Furthermore, we describe also attempts to control this plasma turbulence with external magnetic perturbations that create chaotic magnetic configurations. Accordingly, the magnetic field lines may become chaotic and then induce a Lagrangian diffusion. Moreover, to discuss nonlinear coupling and intermittency, we present results obtained by using numerical techniques as bi spectral and wavelet analyses. (author)

  19. Micro Plasma Spectrometer

    National Aeronautics and Space Administration — The purpose of this IRAD project is to develop a preliminary design elements of miniature electron and ion plasma spectrometers and supporting electronics, focusing...

  20. Gingival plasma cell granuloma

    Amitkumar B Pandav

    2012-01-01

    Full Text Available Plasma cell granuloma, also known as inflammatory pseudotumor is a tumor-like lesion that manifests primarily in the lungs. But it may occur in various other anatomic locations like orbit, head and neck, liver and rarely in the oral cavity. We here report an exceedingly rare case of gingival plasma cell granuloma in a 58 year old woman who presented with upper gingival polypoidal growth. The histopathological examination revealed a mass composed of proliferation of benign spindle mesenchymal cells in a loose myxoid and fibrocollagenous stroma along with dense infiltrate of chronic inflammatory cells predominantly containing plasma cells. Immunohistochemistry for kappa and lambda light chains showed a polyclonal staining pattern confirming a diagnosis of plasma cell granuloma.

  1. Computational plasma physics

    Killeen, J.

    1975-08-01

    The behavior of a plasma confined by a magnetic field is simulated by a variety of numerical models. Some models used on a short time scale give detailed knowledge of the plasma on a microscopic scale, while other models used on much longer time scales compute macroscopic properties of the plasma dynamics. In the last two years there has been a substantial increase in the numerical modelling of fusion devices. The status of MHD, transport, equilibrium, stability, Vlasov, Fokker-Planck, and Hybrid codes is reviewed. These codes have already been essential in the design and understanding of low and high beta toroidal experiments and mirror systems. The design of the next generation of fusion experiments and fusion test reactors will require continual development of these numerical models in order to include the best available plasma physics description and also to increase the geometric complexity of the model. (auth)

  2. Plasma sprayed thermoregulating coatings

    Kudinov, V.V.; Puzanov, A.A.; Zambrzhitskij, A.P.; Soboleva, V.V.

    1979-01-01

    Shown is the possibility of plasma spraying application for thermoregulating coating formation. Given are test results of service properties of BeO, Al 2 O 2 plasma coatings on the substrates of the MA2-1 magnesium alloy. Described is a device for studying durability of coating optical parameters under ultraviolet irradiation in deep vacuum. Dynamics of absorption coefficient, growth caused by an increase in absorption centers amount under such irradiation is investigated

  3. Carbon plasma gun

    Mendel, C.W. Jr.; Zagar, D.M.; Mills, G.S.; Humphries, S. Jr.; Goldstein, S.A.

    1980-01-01

    A family of plasma guns supplying highly ionized carbon plasma is described. The guns are simple and inexpensive to construct and are pulsed by small capacitor banks of a few hundred joules. The output consists of 10 17 --10 18 multiply ionized carbon ions traveling at about 10 7 cm/s. Neutral output is very low and arrives well after the ionized carbon. The guns and pulsers are very reliable

  4. Plasma emission mechanisms

    Melrose, D.B.

    1985-01-01

    Only three emission processes are thought to play a role in solar radio emission: plasma emission, gyromagnetic emission and bremsstrahlung. In this chapter plasma emission is discussed and the processes involved in its production are treated, namely, the generation of Langmuir turbulence, the partial conversion into fundamental transverse radiation, production of secondary Langmuir waves and the generation of second-harmonic transverse radiation. (U.K.)

  5. Heating in toroidal plasmas

    Canobbio, E.

    1981-01-01

    This paper reports on the 2nd Joint Grenoble-Varenna International Symposium on Heating in Toroidal Plasmas, held at Como, Italy, from the 3-12 September 1980. Important problems in relation to the different existing processes of heating. The plasma were identified and discussed. Among others, the main processes discussed were: a) neutral beam heating, b) ion-(electron)-cyclotron resonance heating, c) hybrid resonance and low frequency heating

  6. Dynamics of magnetospheric plasmas

    Horwitz, J.L.

    1985-01-01

    The dynamical behavior of the magnetospheric plasmas which control the electrostatic charging of spacecraft is the result of the complex interaction of a variety of production, loss, transport, and energization mechanisms in the magnetosphere. This paper is intended to provide the spacecraft engineer with a foundation in the basic morphology and controlling processes pertaining to magnetospheric plasma dynamics in the inner magnetosphere, including the synchronous orbit region. 32 references

  7. Radio frequency plasma excitation

    Burden, M.St.J.; Cross, K.B.

    1979-01-01

    An investigation into the use of rf sputtering for ion cleaning of insulating substrates before ion plating is reported. Initial experiments consisted of sputtering metals with rf power followed by the deposition of copper onto glass slides using rf plasma excitation and biasing supply. It was found that good quality films were obtained by rf ion plating onto plastics with excellent adhesion over a wide operating pressure range. A block schematic of the rf plasma excitation system is shown. (UK)

  8. Multicusp plasma containment apparatus

    Limpaecher, R.

    1980-01-01

    It has been discovered that plasma containment by a chamber having multi-pole magnetic cusp reflecting walls in combination with electronic injection for electrostatic containment provides the means for generating magnetic field free quiescent plasmas for practical application in ion-pumps, electronic switches, and the like. 1250 ''alnico v'' magnets 1/2 '' X 1/2 '' X 1 1/2 '' provide containment in one embodiment. Electromagnets embodying toroidal funneling extend the principle to fusion apparatus

  9. Numerical simulation of plasmas

    Dnestrovskii, Y.N.; Kostomarov, D.P.

    1986-01-01

    This book contains a modern consistent and systematic presentation of numerical computer simulation of plasmas in controlled thermonuclear fusion. The authors focus on the Soviet research in mathematical modelling of Tokamak plasmas, and present kinetic hydrodynamic and transport models with special emphasis on the more recent hybrid models. Compared with the first edition (in Russian) this book has been greatly revised and updated. (orig./WL)

  10. Oscillations in quasineutral plasmas

    Grenier, E.

    1996-01-01

    The purpose of this article is to describe the limit, as the vacuum electric permittivity goes to zero, of a plasma physics system, deduced from the Vlasov-Poisson system for special initial data (distribution functions which are analytic in the space variable, with compact support in velocity), a limit also called open-quotes quasineutral regimeclose quotes of the plasma, and the related oscillations of the electric field, with high frequency in time. 20 refs

  11. Measuring the Plasma Density of a Ferroelectric Plasma Source in an Expanding Plasma

    Dunaevsky, A.; Fisch, N.J.

    2003-01-01

    The initial density and electron temperature at the surface of a ferroelectric plasma source were deduced from floating probe measurements in an expanding plasma. The method exploits negative charging of the floating probe capacitance by fast flows before the expanding plasma reaches the probe. The temporal profiles of the plasma density can be obtained from the voltage traces of the discharge of the charged probe capacitance by the ion current from the expanding plasma. The temporal profiles of the plasma density, at two different distances from the surface of the ferroelectric plasma source, could be further fitted by using the density profiles for the expanding plasma. This gives the initial values of the plasma density and electron temperature at the surface. The method could be useful for any pulsed discharge, which is accompanied by considerable electromagnetic noise, if the initial plasma parameters might be deduced from measurements in expanding plasma

  12. From particles to plasmas

    Van Dam, J.W.

    1989-01-01

    The title of this book, From Particles to Plasmas, has more than one meaning. First, it reflects how the scientific career of Marshall Rosenbluth has evolved, beginning in the field of elementary particle physics and extending into his major area of plasma physics. Secondly, it is meant to suggest the wide spectrum of subject matters addressed in the individual lectures, ranging from numerical simulation and space physics and accelerators to various subfields in the physics of plasmas. In the third place, the title is a reference to the way in which the theoretical description of plasmas is often constructed, namely starting from the motion of single particles and then incorporating collective effects. Most of the contributions in this book do concern various aspects of fusion plasma physics, which is the field in which most of Marshall Rosenbluth's scientific contributions have been and are being made. In this field his eminence and authority are indicated by the sobriquet pope of plasma physics that is often applied to him

  13. Plasma control device

    Matsutomi, Akiyoshi.

    1995-01-01

    Plasma position and shape estimation values are outputted based on measured values of coil current. When the measured values of the position and the shape are judged to be abnormal, position and shape estimation values estimated by a plasma position and shape estimation means are outputted as position and shape feed back values to a plasma position and shape control means instead of the position and shape measured values. Since only a portion of the abnormal position and shape measured values may also be replaced with the position and shape estimation values, errors in the plasma position and shape feed back values can be reduced as a whole. In addition, even if the position and shape measured values are abnormal or if they can not be measured, plasma control can be continued by alternative position and shape estimation values, thereby enabling to avoid interruption of plasma control. Since the position and shape estimation values are obtained not only with the measured values of coil current but also with the position and shape estimation values, the accuracy is improved. Further, noises superposed on the position and shape measured values are filtered, and the device is stabilized compared with a prior art device. (N.H.)

  14. Plasma position control device

    Takase, Haruhiko.

    1987-01-01

    Purpose: To conduct position control stably to various plasmas and reduce the burden on the control coil power source. Constitution: Among the proportional, integration and differentiation controls, a proportional-differentiation control section and an integration control section are connected in parallel. Then, a signal switching circuit is disposed to the control signal input section for the proportional-differentiation control section such that either a present position of plasmas or deviation between the present plasma position and an aimed value can be selected as a control signal depending on the control procedures or the state of the plasmas. For instance, if a rapid response is required for the control, the deviation between the present plasma position and the aimed value is selected as the input signal to conduct proportional, integration and differentiation controls. While on the other hand, if it is intended to reduce the burden on the control coil power source, it is adapted such that the control signal inputted to the proportional-differentiation control section itself can select the present plasma position. (Yoshihara, H.)

  15. Thermal plasmas: fundamental aspects

    Fauchais, P.

    2005-01-01

    This article treats of thermal plasmas, i.e. mainly produced by electric arcs and RF discharges. Their main characteristic is that they are generated at a pressure close to the atmospheric pressure (between 10 4 and 10 6 Pa) and refer to the classical kinetics of the Boltzmann equation. Because of the pressure, the collisions between particles are numerous and ionization is mainly due to a thermal effect. They correspond to electron densities between 10 20 and 10 24 m -3 and temperatures between 6000 and 25000 K. In these plasmas, the electric fields and the average free trajectories are too weak to generate a ionization state by direct inelastic collision. Ionization is thus essentially a thermal phenomenon due to elastic collisions. This article presents: 1 - the particles present in a plasma: definition, energy states; 2 - characteristic data: collisions, average free path and collision cross-section, distribution function, ionization types, charged particles mobility inside an electric field, scattering, Debye length; 3 - plasmas at the thermodynamical equilibrium: conditions of equilibrium, calculation of composition, thermodynamic properties, transport properties, radiation; 4 - thermal plasmas away from equilibrium: conditions of non-equilibrium, calculation of plasma composition, calculation of transport properties, quenching phenomenon. (J.S.)

  16. Online plasma calculator

    Wisniewski, H.; Gourdain, P.-A.

    2017-10-01

    APOLLO is an online, Linux based plasma calculator. Users can input variables that correspond to their specific plasma, such as ion and electron densities, temperatures, and external magnetic fields. The system is based on a webserver where a FastCGI protocol computes key plasma parameters including frequencies, lengths, velocities, and dimensionless numbers. FastCGI was chosen to overcome security problems caused by JAVA-based plugins. The FastCGI also speeds up calculations over PHP based systems. APOLLO is built upon the WT library, which turns any web browser into a versatile, fast graphic user interface. All values with units are expressed in SI units except temperature, which is in electron-volts. SI units were chosen over cgs units because of the gradual shift to using SI units within the plasma community. APOLLO is intended to be a fast calculator that also provides the user with the proper equations used to calculate the plasma parameters. This system is intended to be used by undergraduates taking plasma courses as well as graduate students and researchers who need a quick reference calculation.

  17. Fueling by coaxial plasma guns

    Marshall, J.

    1977-01-01

    A review of the operational characteristics of ''snowplow'' and ''deflagration'' coaxial plasma guns is given. The injection of these plasmas into containment fields is discussed. The effect of a background plasma on low-beta injection is mentioned. The use of high-beta injection for reactor plasmas is described

  18. Numerical simulation in plasma physics

    Samarskii, A.A.

    1980-01-01

    Plasma physics is not only a field for development of physical theories and mathematical models but also an object of application of the computational experiment comprising analytical and numerical methods adapted for computers. The author considers only MHD plasma physics problems. Examples treated are dissipative structures in plasma; MHD model of solar dynamo; supernova explosion simulation; and plasma compression by a liner. (Auth.)

  19. Plasma-based accelerator structures

    Schroeder, Carl B.

    1999-01-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas

  20. Physics of partially ionized plasmas

    Krishan, Vinod

    2016-01-01

    Plasma is one of the four fundamental states of matter; the other three being solid, liquid and gas. Several components, such as molecular clouds, diffuse interstellar gas, the solar atmosphere, the Earth's ionosphere and laboratory plasmas, including fusion plasmas, constitute the partially ionized plasmas. This book discusses different aspects of partially ionized plasmas including multi-fluid description, equilibrium and types of waves. The discussion goes on to cover the reionization phase of the universe, along with a brief description of high discharge plasmas, tokomak plasmas and laser plasmas. Various elastic and inelastic collisions amongst the three particle species are also presented. In addition, the author demonstrates the novelty of partially ionized plasmas using many examples; for instance, in partially ionized plasma the magnetic induction is subjected to the ambipolar diffusion and the Hall effect, as well as the usual resistive dissipation. Also included is an observation of kinematic dynam...

  1. Echo phenomena in a plasma

    Pavlenko, V.N.

    1983-01-01

    The mechanism of echo phenomenon in different plasma media: laboratory and cosmic plasma, metals and semiconductors is analyzed to get a more comprehensive idea on collective processes in a plasma and for practical applications in radiophysics and plasma diagnostics. The echo phenomenon permitted to confirm a reversible nature of the Landau damping, to prove the fact that the information on perturbation is conserved in a plasma (as non-damping oscillations of the distribution function) even after disappearing of the macroscopic field. The dependence of the diffusion coefficient on the velocity is measured, microturbulences in a plasma are investigated. New ways of the plasma wave conversion are suggested, as well as ''lightning'' of super-critical plasma layers and regions of plasma non-transparency. Prospective advantages of using echo for studying the mechanisms of charged particle interaction with the surface bounding a plasma are revealed

  2. Dust in flowing magnetized plasma

    Pandey, Birendra P.; Samarian, Alex A.; Vladimirov, Sergey V.

    2009-01-01

    Plasma flows occur in almost every laboratory device and interactions of flowing plasmas with near-wall impurities and/or dust significantly affects the efficiency and lifetime of such devices. The charged dust inside the magnetized flowing plasma moves primarily under the influence of the plasma drag and electric forces. Here, the charge on the dust, plasma potential, and plasma density are calculated self-consistently. The electrons are assumed non-Boltzmannian and the effect of electron magnetization and electron-atom collisions on the dust charge is calculated in a self-consistent fashion. For various plasma magnetization parameters viz. the ratio of the electron and ion cyclotron frequencies to their respective collision frequencies, plasma-atom and ionization frequencies, the evolution of the plasma potential and density in the flow region is investigated. The variation of the dust charge profile is shown to be a sensitive function of plasma parameters. (author)

  3. Uma ferramenta para planejamento de estudos para concursos

    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.

  4. Desarrollo y evaluación de técnicas espectrocópicas basadas en plasmas inducidos por láser y en descargas luminiscentes estimuladas con campos magnéticos para el análisis directo de sólidos

    Vega Reguilón, Paola

    2016-01-01

    El gran desarrollo de nuevos materiales impulsa la investigación en las técnicas de análisis directo de sólidos, en particular de aquellas que permiten obtener información sobre la distribución espacial de la composición elemental de un material (tanto en superficie como en profundidad), información que quedaría destruida si la muestra fuese disuelta. Una de estas técnicas es la descarga luminiscente generada mediante radiofrecuencia (rf-GD) que consiste en un plasma a baja presión que acopl...

  5. Desenvolvimento de colunas cromatográficas de meios de acesso restrito proteína-imobilizada e suas avaliações para análise de fármacos com injeção direta de plasma humano

    Lima Virgínia Veronica de

    2006-01-01

    Full Text Available A series of bovine serum albumin-immobilized supports have been prepared and used as restricted access media (RAM columns. Restricted-access supports combine size-exclusion of proteins and other high-molar-mass matrix components with the simultaneous enrichment of low-molar mass analytes. These characteristics were chromatographically evaluated for the columns. The RAM-BSA (Bovine Serum Albumin columns showed excellent performance for exclusion of human plasma protein with good retention capacity for a series of acidic, basic, and neutral drugs.

  6. Plasma particle accelerators

    Dawson, J.M.

    1988-01-01

    The Superconducting Supercollider (SSC) will require an 87-kilometer accelerator ring to boost particles to 40 TeV. The SSC's size is due in part to the fact that its operating principle is the same one that has dominated accelerator design for 50 years: it guides particles by means of magnetic fields and propels them by strong electric fields. If one were to build an equally powerful but smaller accelerator, one would need to increase the strength of the guiding and propelling fields. Actually, however, conventional technology may not be able to provide significant increases in field strength. There are two reasons. First, the forces from magnetic fields are becoming greater than the structural forces that hold a magnetic material together; the magnets that produce these fields would themselves be torn apart. Second, the energy from electric fields is reaching the energies that bind electrons to atoms; it would tear electrons from nuclei in the accelerator's support structures. It is the electric field problem that plasma accelerators can overcome. Plasma particle accelerators are based on the principle that particles can be accelerated by the electric fields generated within a plasma. Because the plasma has already been ionized, plasma particle accelerators are not susceptible to electron dissociation. They can in theory sustain accelerating fields thousands of times stronger that conventional technologies. So far two methods for creating plasma waves for accelerators have been proposed and tested: the wakefield and the beat wave. Although promising electric fields have been produced, more research is necessary to determine whether plasma particle accelerators can compete with the existing accelerators. 7 figs

  7. Plasma state. The universe's fire

    Lehner, Th.

    2004-01-01

    The plasma is the fourth state of matter, obtained at a very high temperature by the separation of the electrons from their nuclei. Plasma represents 99% of the visible mass of our present day universe and was the unique state of matter at its very beginning. Plasmas are present in the core of stars and in the interstellar environment. More closer to us, they are responsible of spectacular phenomena, like aurora borealis, lightning, comet queues etc.. This book makes a review of the different types of plasmas (electromagnetic, Earth's plasmas, spatial plasmas, solar plasmas, astrophysical plasmas). One chapter presents the thermonuclear fusion as future energy source. Another one treats of the chaos and turbulence inside plasmas. Some applications of plasmas are reviewed: MHD and ionic propulsion systems, MHD energy conversion and MHD generators, thermo-ionic converters, solid-state plasmas, particle accelerators, coherent radiation sources, 'Zeta' machines, X-ray lasers, isotopic separation, non-neutral plasmas and charged beams, free-electrons lasers, electrons and positrons plasmas, industrial applications (etching and cleaning, manufacturing of solar cells, flat screens, industrial reactors, waste treatment, cold plasma-assisted sterilization, effluents decontamination etc.). A last chapter makes an overview of the modern research in plasma physics. (J.S.)

  8. Integrated modelling of the edge plasma and plasma facing components

    Coster, D.P.; Bonnin, X.; Mutzke, A.; Schneider, R.; Warrier, M.

    2007-01-01

    Modelling of the interaction between the edge plasma and plasma facing components (PFCs) has tended to place more emphasis on either the plasma or the PFCs. Either the PFCs do not change with time and the plasma evolution is studied, or the plasma is assumed to remain static and the detailed interaction of the plasma and the PFCs are examined, with no back-reaction on the plasma taken into consideration. Recent changes to the edge simulation code, SOLPS, now allow for changes in both the plasma and the PFCs to be considered. This has been done by augmenting the code to track the time-development of the properties of plasma facing components (PFCs). Results of standard mixed-materials scenarios (base and redeposited C; Be) are presented

  9. Plasma rico en plaquetas Platelet -rich plasma

    J. González Lagunas

    2006-01-01

    El Plasma Rico en Plaquetas es una suspensión concentrada de la sangre centrifugada que contiene elevadas concentraciones de trombocitos. Durante los últimos años, este producto ha aparecido de forma repetida en publicaciones científicas y en medios de comunicación generales como un producto que por sus características induce la curación y regeneración de los tejidos. La premisa de su uso es que las elevadas concentraciones de plaquetas en el PRP, liberan cantidades significativas de factores...

  10. ¿Argumentar para definir o definir para argumentar?

    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...

  11. Low Temperature Plasma Medicine

    Graves, David

    2013-10-01

    Ionized gas plasmas near room temperature are used in a remarkable number of technological applications mainly because they are extraordinarily efficient at exploiting electrical power for useful chemical and material transformations near room temperature. In this tutorial address, I will focus on the newest area of low temperature ionized gas plasmas (LTP), in this case operating under atmospheric pressure conditions, in which the temperature-sensitive material is living tissue. LTP research directed towards biomedical applications such as sterilization, surgery, wound healing and anti-cancer therapy has seen remarkable growth in the last 3-5 years, but the mechanisms responsible for the biomedical effects have remained mysterious. It is known that LTP readily create reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS (or RONS), in addition to a suite of other radical and non-radical reactive species, are essential actors in an important sub-field of aerobic biology termed ``redox'' (or oxidation-reduction) biology. I will review the evidence suggesting that RONS generated by plasmas are responsible for their observed therapeutic effects. Other possible bio-active mechanisms include electric fields, charges and photons. It is common in LTP applications that synergies between different mechanisms can play a role and I will review the evidence for synergies in plasma biomedicine. Finally, I will address the challenges and opportunities for plasma physicists to enter this novel, multidisciplinary field.

  12. Mechanisms of Plasma Therapeutics

    Graves, David

    2015-09-01

    In this talk, I address research directed towards biomedical applications of atmospheric pressure plasma such as sterilization, surgery, wound healing and anti-cancer therapy. The field has seen remarkable growth in the last 3-5 years, but the mechanisms responsible for the biomedical effects have remained mysterious. It is known that plasmas readily create reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS (or RONS), in addition to a suite of other radical and non-radical reactive species, are essential actors in an important sub-field of aerobic biology termed ``redox'' (or oxidation-reduction) biology. It is postulated that cold atmospheric plasma (CAP) can trigger a therapeutic shielding response in tissue in part by creating a time- and space-localized, burst-like form of oxy-nitrosative stress on near-surface exposed cells through the flux of plasma-generated RONS. RONS-exposed surface layers of cells communicate to the deeper levels of tissue via a form of the ``bystander effect,'' similar to responses to other forms of cell stress. In this proposed model of CAP therapeutics, the plasma stimulates a cellular survival mechanism through which aerobic organisms shield themselves from infection and other challenges.

  13. Plasma treatment of onychomycosis

    Xiong, Zilan; Roe, Jeff; Grammer, Tim; Him, Yeon-Ho; Graves, David B.

    2015-09-01

    Onychomycosis or fungal infection of the toenail or fingernail is a common affliction. Approximately 10% of the world's adult population is estimated to suffer from onychomycosis. Current treatment options such as topical creams, oral drugs, or laser treatments are generally limited by a variety of problems. We present results for an alternative onychomycosis treatment scheme using atmospheric pressure cold air plasmas. Using thinned cow hoof as a model nail material, we tested the ability of various plasma sources to act through the model nail to eradicate either bacteria or fungus deposited on the opposite side. Following 20 minute exposure to a surface microdischarge (SMD) device operating in room air, we observed a ~ 2 log reduction of E. coli. A similar result was obtained against T. rubrum after 45 min plasma treatment. NOx species concentration penetrating through the model nail as well as uptake into the nail were measured as a function of nail thickness. We propose that these plasma-generated species, or perhaps their reaction products, are responsible for at least part of the observed anti-microbial effect. We also explore the use of ultraviolet light acting in synergy with plasma-generated chemical species.

  14. ITER plasma facing components

    Kuroda, T.; Vieider, G.; Akiba, M.

    1991-01-01

    This document summarizes results of the Conceptual Design Activities (1988-1990) for the International Thermonuclear Experimental Reactor (ITER) project, namely those that pertain to the plasma facing components of the reactor vessel, of which the main components are the first wall and the divertor plates. After an introduction and an executive summary, the principal functions of the plasma-facing components are delineated, i.e., (i) define the low-impurity region within which the plasma is produced, (ii) absorb the electromagnetic radiation and charged-particle flux from the plasma, and (iii) protect the blanket/shield components from the plasma. A list of critical design issues for the divertor plates and the first wall is given, followed by discussions of the divertor plate design (including the issues of material selection, erosion lifetime, design concepts, thermal and mechanical analysis, operating limits and overall lifetime, tritium inventory, baking and conditioning, safety analysis, manufacture and testing, and advanced divertor concepts) and the first wall design (armor material and design, erosion lifetime, overall design concepts, thermal and mechanical analysis, lifetime and operating limits, tritium inventory, baking and conditioning, safety analysis, manufacture and testing, an alternative first wall design, and the limiters used instead of the divertor plates during start-up). Refs, figs and tabs

  15. Plasma-Wall Interactions

    Li, J; Chen, J L [Institute of Plasma Physics, Chinese Academy of Sciences (China); Guo, H Y [Tri Alpha Energy (United States); Institute of Plasma Physics, Chinese Academy of Sciences (China); McCracken, G M [Culham Science Centre, UKAEA, Abingdon (United Kingdom)

    2012-09-15

    The problem of impurities in fusion plasmas has been recognized since the beginning of the fusion programme. Early experiments in glass vacuum vessels released gas from the wall to such an extent that the radiation from the impurities prevented the plasma from being heated above about 50 eV. The radiative power loss is principally due to line radiation from partially stripped ions, which is particularly a problem during the plasma startup phase. Another problem is fuel dilution, which arises because impurity atoms produce many electrons and, for a given plasma pressure, these electrons take the place of fuel particles. Impurities can also lead to disruptions, as a result of edge cooling and consequent current profile modification. The fractional impurity level which radiates 10% of the total thermonuclear power for a 10 keV plasma is 50% for helium, 7% for carbon, and less than 0.1% for molybdenum. Clearly, impurities of low atomic number are a much less serious problem than those of high atomic number. (author)

  16. Plasma nuclear fusion method

    Yamazaki, Shunpei; Miyanaga, Shoji; Wakaizumi, Kazuhiro; Takemura, Yasuhiko.

    1990-01-01

    Nuclear fusion reactions are attained by plasma gas phase reactions using magnetic fields and microwaves, and the degree of the reactions is controlled. That is, deuterium (D 2 ) is introduced into a plasma container by utilizing the resonance of microwaves capable of generating plasmas at high density higher by more than 10 - 10 3 times as compared with the high frequency and magnetic fields, and an electric energy is applied to convert gaseous D 2 into plasmas and nuclear fusion is conducted. Further, the deuterium ions in the plasmas are attracted to a surface of a material causing nuclear fusion under a negatively biased electric field from the outside (typically represented by Pd or Ti). Then, deuterium nuclei (d) or deuterium ions collide to the surface of the cathode on the side of palladium to conduct nuclear reaction at the surface or the inside (vicinity) thereof. However, a DC bias is applied as an external bias with the side of the palladium being negative. The cold nuclear fusion was demonstrated by placing a neutron counter in the vicinity of the container and confirming neutrons generated there. (I.S.)

  17. Plasma-surface interactions

    Goeckner, M J; Nelson, C T; Sant, S P; Jindal, A K; Joseph, E A; Zhou, B S; Padron-Wells, G; Jarvis, B; Pierce, R; Overzet, L J

    2008-01-01

    Materials processing is at a crossroads. Currently a large fraction of industrially viable materials processing is via plasmas. Until recently it has been economical to just examine the influence the plasma properties on the desired surface processes and through this ultimately optimize manufacturing. For example, it is well known that the surface processes (etch or deposition), occur in the top few mono-layers of the surface. Thus, in film growth one requires that molecules from the gas-phase land and bond on the surface. However as processing has reached the nano-scale, development of viable processes has become more and more difficult. In part, this is because of all of the free parameters that exist in plasmas. To overcome this economic issue, tool vendors and semiconductor companies have turned to complex computational models of processing plasmas. For those models to work, one requires a through understanding of all of the gas-phase and surface-phase processes that are exhibited in plasmas. Unfortunately, these processes, particularly those at the surface, are not well understood. In this article we describe a viable model of the surface-phase based on cross sections for processes that occur. While originally developed of fluorocarbon systems, the model also appears to be applicable to hydrocarbon systems.

  18. Plasma-surface interactions

    Goeckner, M J; Nelson, C T; Sant, S P; Jindal, A K; Joseph, E A; Zhou, B S; Padron-Wells, G; Jarvis, B; Pierce, R; Overzet, L J [Department of Electrical Engineering, University of Texas at Dallas (United States)], E-mail: goeckner@utdallas.edu

    2008-10-01

    Materials processing is at a crossroads. Currently a large fraction of industrially viable materials processing is via plasmas. Until recently it has been economical to just examine the influence the plasma properties on the desired surface processes and through this ultimately optimize manufacturing. For example, it is well known that the surface processes (etch or deposition), occur in the top few mono-layers of the surface. Thus, in film growth one requires that molecules from the gas-phase land and bond on the surface. However as processing has reached the nano-scale, development of viable processes has become more and more difficult. In part, this is because of all of the free parameters that exist in plasmas. To overcome this economic issue, tool vendors and semiconductor companies have turned to complex computational models of processing plasmas. For those models to work, one requires a through understanding of all of the gas-phase and surface-phase processes that are exhibited in plasmas. Unfortunately, these processes, particularly those at the surface, are not well understood. In this article we describe a viable model of the surface-phase based on cross sections for processes that occur. While originally developed of fluorocarbon systems, the model also appears to be applicable to hydrocarbon systems.

  19. Optical plasma torch electron bunch generation in plasma wakefield accelerators

    G. Wittig

    2015-08-01

    Full Text Available A novel, flexible method of witness electron bunch generation in plasma wakefield accelerators is described. A quasistationary plasma region is ignited by a focused laser pulse prior to the arrival of the plasma wave. This localized, shapeable optical plasma torch causes a strong distortion of the plasma blowout during passage of the electron driver bunch, leading to collective alteration of plasma electron trajectories and to controlled injection. This optically steered injection is more flexible and faster when compared to hydrodynamically controlled gas density transition injection methods.

  20. Plasma cleaning for waste minimization

    Ward, P.P.

    1993-07-01

    Although plasma cleaning is a recognized substitute for solvent cleaning in removing organic contaminants, some universal problems in plasma cleaning processes prevent wider use of plasma techniques. Lack of understanding of the fundamental mechanisms of the process, unreliable endpoint detection techniques, and slow process times make plasma cleaning processes less than desirable. Our approach to address these plasma cleaning problems is described. A comparison of plasma cleaning rates of oxygen and oxygen/sulfur hexafluoride gases shows that fluorine-containing plasmas can enhance etch rates by 400% over oxygen alone. A discussion of various endpoint indication techniques is discussed and compared for application suitability. Work toward a plasma cleaning database is discussed. In addition to the global problems of plasma cleaning, an experiment where the specific mixed-waste problem of removal of machine oils from radioactive scrap metal is discussed.

  1. Plasma Colloquium Travel Grant Program

    Hazeltine, R.D.

    1998-01-01

    OAK B188 Plasma Colloquium Travel Grant Program. The purpose of the Travel Grant Program is to increase the awareness of plasma research. The new results and techniques of plasma research in fusion plasmas, plasma processing space plasmas, basic plasma science, etc, have broad applicability throughout science. The benefits of these results are limited by the relatively low awareness and appreciation of plasma research in the larger scientific community. Whereas spontaneous interactions between plasma scientists and other scientists are useful, a focused effort in education and outreach to other scientists is efficient and is needed. The academic scientific community is the initial focus of this effort, since that permits access to a broad cross-section of scientists and future scientists including undergraduates, graduate students, faculty, and research staff

  2. Plasma rico en plaquetas Platelet -rich plasma

    J. González Lagunas

    2006-04-01

    Full Text Available El Plasma Rico en Plaquetas es una suspensión concentrada de la sangre centrifugada que contiene elevadas concentraciones de trombocitos. Durante los últimos años, este producto ha aparecido de forma repetida en publicaciones científicas y en medios de comunicación generales como un producto que por sus características induce la curación y regeneración de los tejidos. La premisa de su uso es que las elevadas concentraciones de plaquetas en el PRP, liberan cantidades significativas de factores de crecimiento. En este artículo se van a recoger las evidencias científicas que se han presentado en la literatura médica con respecto al PRP y a la curación ósea, así como las diferentes aplicaciones clínicas que se han sugerido.Platelet-rich plasma is a by-product of centrifuged whole blood that contains high levels of thrombocytes. In the last decade, scientific and media interest has been generated by this product that apparently has the capacity of inducing and promoting tissue healing and regeneration. The premise of its use is that the large number of platelets in PRP release significant amounts of growth factors. In this paper, a critical review of the medical literature regarding PRP and bone healing will be presented. Also, the suggested clinical applications of the product will be addressed.

  3. Taller para desarrollar la creatividad

    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...

  4. Atoms in dense plasmas

    More, R.M.

    1987-01-01

    This paper covers some aspects of the theory of atomic processes in dense plasmas. Because the topic is very broad, a few general rules which give useful guidance about the typical behavior of dense plasmas have been selected. These rules are illustrated by semiclassical estimates, scaling laws and appeals to more elaborate calculations. Included in the paper are several previously unpublished results including a new mechanism for electron-ion heat exchange (section II), and an approximate expression for oscillator-strengths of highly charged ions (section V). However the main emphasis is not upon practical formulas but rather on questions of fundamental theory, the structural ingredients which must be used in building a model for plasma events. What are the density effects and how does one represent them? Which are most important? How does one identify an incorrect theory? The general rules help to answer these questions. 106 references, 23 figures, 2 tables

  5. Corpuscular plasma diagnostics

    Afrosimov, V.; Petrov, M.

    1984-01-01

    An elementary explanation is presented of the physical principles and important methods of corpuscular plasma diagnostics. The invaluable role of corpuscular methods for measuring the hot plasma ion component in thermonuclear facilities, especially hydrogen ions in tokamaks, is emphasized. All corpuscular methods employ analysis of fast neutral atoms and therefore the mechanism of their creation inside a hot plasma is explained first. The ammount of information obtainable from spectra of fast neutrals is discussed. Multichannel analyzers developed at the FTI A.F. Ioffe in Leningrad are described in detail. Classical passive corpuscular diagnostics are examined as are active methods using artifitial beams of hydrogen atoms. The method used for obtaining local values of ion temperature and density is explained. Corpuscular spectroscopic diagnostics and its application for measuring impurities is mentioned. (J.U.)

  6. Plasma cell leukemia

    Fernández de Larrea, C; Kyle, R A; Durie, B G M

    2013-01-01

    Plasma cell leukemia (PCL) is a rare and aggressive variant of myeloma characterized by the presence of circulating plasma cells. It is classified as either primary PCL occurring at diagnosis or as secondary PCL in patients with relapsed/refractory myeloma. Primary PCL is a distinct clinic......-pathological entity with different cytogenetic and molecular findings. The clinical course is aggressive with short remissions and survival duration. The diagnosis is based upon the percentage (≥ 20%) and absolute number (≥ 2 × 10(9)/l) of plasma cells in the peripheral blood. It is proposed that the thresholds...... regimens and bortezomib-based regimens are recommended followed by high-dose therapy with autologous stem cell transplantation if feasible. Allogeneic transplantation can be considered in younger patients. Prospective multicenter studies are required to provide revised definitions and better understanding...

  7. Plasma processing of nanomaterials

    Sankaran, R Mohan

    2014-01-01

    CRC Press author R. Mohan Sankaran is the winner of the 2011 Peter Mark Memorial Award "… for the development of a tandem plasma synthesis method to grow carbon nanotubes with unprecedented control over the nanotube properties and chirality." -2011 AVS Awards Committee"Readers who want to learn about how nanomaterials are processed, using the most recent methods, will benefit greatly from this book. It contains very recent technical details on plasma processing and synthesis methods used by current researchers developing new nano-based materials, with all the major plasma-based processing techniques used today being thoroughly discussed."-John J. Shea, IEEE Electrical Insulation Magazine, May/June 2013, Vol. 29, No. 3.

  8. [Plasma properties: Annual report

    1987-01-01

    The Magneto-Fluid Dynamics Division of the Courant Institute is engaged in a broad program of basic research in the theoretical aspects of plasma physics and magneto-fluid dynamics with emphasis on those areas which are relevant to the fusion energy program. The total research program in the division includes efforts in the areas of plasma containment, stability, equilibrium, transport, wave propagation (including shock waves), heating, orbit theory, as well as numerical experiments and the development of practical numerical methods in all plasma problems. Applications are made to the following project areas: Tokamaks, Mirrors, Stellarators, and Alternate Concepts. Developments include the whole spectrum of models from macroscopic MHD and guiding center to Vlasov, drift kinetic Fokker-Planck, and Boltzmann. This document describes research completed as well as programs in progress

  9. Heating in toroidal plasmas

    Knoepfel, H.; Mazzitelli, G.

    1984-01-01

    The article is a rather detailed report on the highlights in the area of the ''Heating in toroidal plasmas'', as derived from the presentations and discussions at the international symposium with the same name, held in Rome, March 1984. The symposium covered both the physics (experiments and theory) and technology of toroidal fusion plasma heating. Both large fusion devices (either already in operation or near completion) requiring auxiliary heating systems at the level of tens of megawatts, as well as physics of their heating processes and their induced side effects (as studied on smaller devices), received attention. Substantial progress was reported on the broad front of auxiliary plasma heating and Ohmic heating. The presentation of the main conclusions of the symposium is divided under the following topics: neutral-beam heating, Alfven wave heating, ion cyclotron heating, lower hybrid heating, RF current drive, electron cyclotron heating, Ohmic heating and special contributions

  10. Relativistic plasma dispersion functions

    Robinson, P.A.

    1986-01-01

    The known properties of plasma dispersion functions (PDF's) for waves in weakly relativistic, magnetized, thermal plasmas are reviewed and a large number of new results are presented. The PDF's required for the description of waves with small wave number perpendicular to the magnetic field (Dnestrovskii and Shkarofsky functions) are considered in detail; these functions also arise in certain quantum electrodynamical calculations involving strongly magnetized plasmas. Series, asymptotic series, recursion relations, integral forms, derivatives, differential equations, and approximations for these functions are discussed as are their analytic properties and connections with standard transcendental functions. In addition a more general class of PDF's relevant to waves of arbitrary perpendicular wave number is introduced and a range of properties of these functions are derived

  11. Plasma Simulation Program

    Greenwald, Martin

    2011-10-04

    Many others in the fusion energy and advanced scientific computing communities participated in the development of this plan. The core planning team is grateful for their important contributions. This summary is meant as a quick overview the Fusion Simulation Program's (FSP's) purpose and intentions. There are several additional documents referenced within this one and all are supplemental or flow down from this Program Plan. The overall science goal of the DOE Office of Fusion Energy Sciences (FES) Fusion Simulation Program (FSP) is to develop predictive simulation capability for magnetically confined fusion plasmas at an unprecedented level of integration and fidelity. This will directly support and enable effective U.S. participation in International Thermonuclear Experimental Reactor (ITER) research and the overall mission of delivering practical fusion energy. The FSP will address a rich set of scientific issues together with experimental programs, producing validated integrated physics results. This is very well aligned with the mission of the ITER Organization to coordinate with its members the integrated modeling and control of fusion plasmas, including benchmarking and validation activities. [1]. Initial FSP research will focus on two critical Integrated Science Application (ISA) areas: ISA1, the plasma edge; and ISA2, whole device modeling (WDM) including disruption avoidance. The first of these problems involves the narrow plasma boundary layer and its complex interactions with the plasma core and the surrounding material wall. The second requires development of a computationally tractable, but comprehensive model that describes all equilibrium and dynamic processes at a sufficient level of detail to provide useful prediction of the temporal evolution of fusion plasma experiments. The initial driver for the whole device model will be prediction and avoidance of discharge-terminating disruptions, especially at high performance, which are a

  12. Exhibidor de cinturones para Montagne

    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...

  13. Colombia competente para la paz

    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.

  14. Pulsed Plasma Electron Sources

    Krasik, Yakov

    2008-11-01

    Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E Saveliev, J. Appl. Phys. 98, 093308 (2005). Ya. E. Krasik, A. Dunaevsky, and J. Felsteiner, Phys. Plasmas 8, 2466 (2001). D. Yarmolich, V. Vekselman, V. Tz. Gurovich, and Ya. E. Krasik, Phys. Rev. Lett. 100, 075004 (2008). J. Z. Gleizer, Y. Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).

  15. Plasma diagnostic reflectometry

    Cohen, B.I.; Afeyan, B.B.; Garrison, J.C.; Kaiser, T.B.; Luhmann, N.C. Jr.; Domier, C.W.; Chou, A.E.; Baang, S.

    1996-01-01

    Theoretical and experimental studies of plasma diagnostic reflectometry have been undertaken as a collaborative research project between the Lawrence Livermore National Laboratory (LLNL) and the University of California Department of Applied Science Plasma Diagnostics Group under the auspices of the Laboratory Directed Research and Development Program at LLNL. Theoretical analyses have explored the basic principles of reflectometry to understand its limitations, to address specific gaps in the understanding of reflectometry measurements in laboratory experiments, and to explore extensions of reflectometry such as ultra-short-pulse reflectometry. The theory has supported basic laboratory reflectometry experiments where reflectometry measurements can be corroborated by independent diagnostic measurements

  16. Protective plasma envelope

    Bocharov, V.N.; Konstantinov, S.G.; Kudryavtsev, A.M.; Myskin, O.K.; Panasyuk, V.M.; Tsel'nik, F.A.

    1984-06-01

    A method of creating an annular plasma envelope used to protect the hot plasma from flows of impurities and gases from the walls of the vacuum chamber is described. The diameter of the envelope is 30 cm, the thickness of the wall is 1.5 cm, the length is 2.5 m, and its density is from 10 13 to 10 14 cm -3 . The envelope attenuates the incident (from outside) flow of helium 10-fold and the low of hydrogen 20-fold

  17. Plasma fractionation issues.

    Farrugia, Albert; Evers, Theo; Falcou, Pierre-Francois; Burnouf, Thierry; Amorim, Luiz; Thomas, Sylvia

    2009-04-01

    Procurement and processing of human plasma for fractionation of therapeutic proteins or biological medicines used in clinical practice is a multi-billion dollar international trade. Together the private sector and public sector (non-profit) provide large amounts of safe and effective therapeutic plasma proteins needed worldwide. The principal therapeutic proteins produced by the dichotomous industry include gamma globulins or immunoglobulins (including pathogen-specific hyperimmune globulins, such as hepatitis B immune globulins) albumin, factor VIII and Factor IX concentrates. Viral inactivation, principally by solvent detergent and other processes, has proven highly effective in preventing transmission of enveloped viruses, viz. HBV, HIV, and HCV.

  18. Dust-Plasma Interactions

    Rosenberg, M.

    2010-01-01

    The objective of our theoretical research under this grant over the past 3 years was to develop new understanding in a range of topics in the physics of dust-plasma interactions, with application to space and the laboratory. We conducted studies related to the physical properties of dust, waves and instabilities in both weakly coupled and strongly coupled dusty plasmas, and innovative possible applications. A major consideration in our choice of topics was to compare theory with experiments or observations, and to motivate new experiments, which we believe is important for developing this relatively new field. Our research is summarized, with reference to our list of journal publications.

  19. Plasma YKL-40

    Jensen, Peter; Wiell, C; Milting, K

    2013-01-01

    Background  Plasma YKL-40 is an inflammatory biomarker. No useful biomarker exists in patients with psoriasis or psoriatic arthritis. Objective  To measure YKL-40 and high-sensitivity C-reactive protein (hs-CRP) in patients with psoriasis or psoriatic arthritis before and during treatment. Methods......-CRP at inclusion and during 48 weeks of adalimumab treatment. The patients with psoriatic arthritis were divided into responders and non-responders. Results  In patients with psoriasis, the baseline median PASI score was 10.8 and baseline YKL-40 was 45 μg/L. Seventeen per cent had elevated plasma YKL-40 compared...

  20. Steam torch plasma modelling

    Jeništa, Jiří

    2017-01-01

    Roč. 37, č. 3 (2017), s. 653-687 ISSN 0272-4324 R&D Projects: GA ČR(CZ) GA15-19444S Institutional support: RVO:61389021 Keywords : Arc * Evaporation * Mass flow rate * Water-vortex stabilization * Net emission coefficients * Partial characteristics * Local thermodynamic equilibrium Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.355, year: 2016 http://link.springer.com/article/10.1007/s11090-017-9789-7

  1. Measurement of plasma parameters

    1999-01-01

    The physics issues of the measurements of the plasma properties necessary to provide both the control and science data for achieving the goals of the ITER device are discussed. The assessment of the requirements for these measurements is first discussed, together with priorities that relate to the experimental program. Subsequently, some of the proposed measurement techniques, the plasma diagnostics, are described with particular emphasis on their implementation on ITER and their capability to meet the requirements. A judgement on the present status of the diagnostic program on ITER is provided with some indication of the research and development program necessary to demonstrate viability of techniques or their implementation. (author)

  2. Plasma wave accelerator. II

    Mori, W.; Joshi, C.; Dawson, J.M.

    1982-01-01

    It was shown that the insertion of a cross magnetic field prevents the particles from getting out of phase with the electric field of the plasma wave in the beat wave accelerator scheme. Thus, using a CO 2 laser, n/sub c//n/sub e/ = (ω 0 /ω/sub p/) 2 approx. 35, and a 300 kG magnetic field, electrons can be (in principle) accelerated to 100 GeV in 2 meters. For comparison without the magnetic field, the same energies may be obtained in a n/sub c//n/sub e/ approx. 10 5 plasma over a distance of 100 meters

  3. Plasma-wall interactions

    Behrisch, Rainer

    1978-01-01

    The plasma wall interactions for two extreme cases, the 'vacuum model' and the 'cold gas blanket' are outlined. As a first step for understanding the plasma wall interactions the elementary interaction processes at the first wall are identified. These are energetic ion and neutral particle trapping and release, ion and neutral backscattering, ion sputtering, desorption by ions, photons and electrons and evaporation. These processes have only recently been started to be investigated in the parameter range of interest for fusion research. The few measured data and their extrapolation into regions not yet investigated are reviewed

  4. Optical properties of cluster plasma

    Kishimoto, Yasuaki; Tajima, Toshiki [Japan Atomic Energy Research Inst., Neyagawa, Osaka (Japan). Kansai Research Establishment; Downer, M C

    1998-03-01

    It is shown that unlike a gas plasma or an electron plasma in a metal, an ionized clustered material (`cluster plasma`) permits propagation below the plasma cut-off of electromagnetic (EM) waves whose phase velocity is close to but below the speed of light. This results from the excitation of a plasma oscillation mode (and/or polarization mode) through the cluster surface which does not exist in usual gaseous plasma. The existence of this new optical mode, cluster mode, is confirmed via numerical simulation. (author)

  5. Plasma effects on subcellular structures

    Gweon, Bomi; Kim, Dan Bee; Jung, Heesoo; Choe, Wonho; Kim, Daeyeon; Shin, Jennifer H.

    2010-01-01

    Atmospheric pressure helium plasma treated human hepatocytes exhibit distinctive zones of necrotic and live cells separated by a void. We propose that plasma induced necrosis is attributed to plasma species such as oxygen radicals, charged particles, metastables and/or severe disruption of charged cytoskeletal proteins. Interestingly, uncharged cytoskeletal intermediate filaments are only minimally disturbed by plasma, elucidating the possibility of plasma induced electrostatic effects selectively destroying charged proteins. These bona fide plasma effects, which inflict alterations in specific subcellular structures leading to necrosis and cellular detachment, were not observed by application of helium flow or electric field alone.

  6. Dynamic plasma screening effects on atomic collisions in dense plasmas

    Young-Dae Jung

    1999-01-01

    Dynamic plasma screening effects are investigated on electron-ion collisional excitation and Coulomb Bremsstrahlung processes in dense plasmas. The electron-ion interaction potential is considered by introduction of the plasma dielectric function. The straight-ling trajectory method is applied to the path of the projectile electron. The transition probability including the dynamic plasma screening effect is found to be always greater than that including the static plasma screening effects. It is found that the differential Bremsstrahlung radiation cross section including the dynamic plasma screening effect is also greater than that including the static plasma screening effect. When the projectile velocity is smaller than the electron thermal velocity, the dynamic polarization screening effect becomes the static plasma screening effect. However, when the projectile velocity is greater than the electron thermal velocity, the interaction potential is almost unshielded

  7. Observation of plasma hole in a rotating plasma

    Nagaoka, Kenichi; Ishihara, Tatsuzo; Okamoto, Atsushi; Yoshimura, Shinji; Tanaka, Masayoshi Y.

    2001-01-01

    Plasma hole, a cylindrical density cavity, formed in a rotating plasma has been investigated experimentally. The plasma hole is characterized by large aspect ratio (length/radius ≥ 30), steep boundary layer between the hole and the ambient plasma (10 ion Larmor radius), and extremely high positive potential (130 V). The flow velocity field associated with plasma hole structure has been measured, and is found to have interesting features: (1) plasma rotates in azimuthal direction at a maximum velocity of order of ion sound speed, (2) plasma flows radially inward across the magnetic field line, (3) there present an axial flow reversal between core and peripheral region. It is found that the flow pattern of the plasma hole is very similar to the that of well-developed typhoon with core. (author)

  8. Partially ionized plasmas including the third symposium on uranium plasmas

    Krishnan, M. [ed.

    1976-09-01

    Separate abstracts are included for 28 papers on electrically generated plasmas, fission generated plasmas, nuclear pumped lasers, gaseous fuel reactor research, and applications. Five papers have been previously abstracted and included in ERA.

  9. Review on plasmas in extraordinary media: plasmas in cryogenic conditions and plasmas in supercritical fluids

    Stauss, Sven; Muneoka, Hitoshi; Terashima, Kazuo

    2018-02-01

    Plasma science and technology has enabled advances in very diverse fields: micro- and nanotechnology, chemical synthesis, materials fabrication and, more recently, biotechnology and medicine. While many of the currently employed plasma tools and technologies are very advanced, the types of plasmas used in micro- and nanofabrication pose certain limits, for example, in treating heat-sensitive materials in plasma biotechnology and plasma medicine. Moreover, many physical properties of plasmas encountered in nature, and especially outer space, i.e. very-low-temperature plasmas or plasmas that occur in high-density media, are not very well understood. The present review gives a short account of laboratory plasmas generated under ’extreme’ conditions: at cryogenic temperatures and in supercritical fluids. The fundamental characteristics of these cryogenic plasmas and cryoplasmas, and plasmas in supercritical fluids, especially supercritical fluid plasmas, are presented with their main applications. The research on such exotic plasmas is expected to lead to further understanding of plasma physics and, at the same time, enable new applications in various technological fields.

  10. Double plasma system with inductively coupled source plasma and quasi-quiescent target plasma

    Massi, M.; Maciel, H.S.

    1995-01-01

    Cold plasmas have successfully been used in the plasma-assisted material processing industry. An understanding of the physicochemical mechanisms involved in the plasma-surface interaction is needed for a proper description of deposition and etching processes at material surfaces. Since these mechanisms are dependent on the plasma properties, the development of diagnostic techniques is strongly desirable for determination of the plasma parameters as well as the characterization of the electromagnetic behaviour of the discharge. In this work a dual discharge chamber, was specially designed to study the deposition of thin films via plasma polymerization process. In the Pyrex chamber an inductively coupled plasma can be excited either in the diffuse low density E-mode or in the high density H-mode. This plasma diffuses into the cylindrical stainless steel chamber which is covered with permanent magnets to produce a multidipole magnetic field configuration at the surface. By that means a double plasma is established consisting of a RF source plasma coupled to a quasi-quiescent target plasma. The preliminary results presented here refer to measurements of the profiles of plasma parameters along the central axis of the double plasma apparatus. Additionally a spectrum analysis performed by means of a Rogowski coil probe immersed into the source plasma is also presented. The discharge is made in argon with pressure varying from 10 -2 to 1 torr, and the rf from 10 to 150 W

  11. Plasma rotation study in Tore Supra radio frequency heated plasmas

    Chouli, Bilal

    2014-01-01

    Toroidal flows are found to improve the performance of the magnetic confinement devices with increase of the plasma stability and confinement. In ITER or future reactors, the torque from NBI should be less important than in present-day tokamaks. Consequently, it is of interest to study other intrinsic mechanisms that can give rise to plasma rotation in order to predict the rotation profile in experiments. Intriguing observations of plasmas rotation have been made in radio frequency (RF) heated plasmas with little or no external momentum injection. Toroidal rotation in both the direction of the plasma current (co-current) and in the opposite direction (counter-current) has been observed depending on the heating schemes and plasma performance. In Tore Supra, most observations in L-mode plasmas have been in the counter-current direction. However, in this thesis, we show that in lower hybrid current drive (LHCD), the core toroidal rotation increment is in co- or counter-current direction depending on the plasma current amplitude. At low plasma current the rotation change is in the co-current direction while at high plasma current, the change is in the counter-current direction. In both low and high plasma current cases, rotation increments are found to increase linearly with the injected LH power. Several mechanisms in competition which can induce co- or counter-current rotation in Tore Supra LHCD plasmas are investigated and typical order of magnitude are discussed in this thesis. (author) [fr

  12. Filamentary magnetohydrodynamic plasmas

    Kinney, R.; Tajima, T.; McWilliams, J.C.; Petviashvili, N.

    1994-01-01

    A filamentary construct of magnetohydrodynamical plasma dynamics based on the Elsaesser variables is developed. This approach is modeled after discrete vortex models of hydrodynamical turbulence, which cannot be expected in general to produce results identical to those based on a Fourier decomposition of the fields. In a highly intermittent plasma, the induction force is small compared to the convective motion, and when this force is neglected, the plasma vortex system is described by a Hamiltonian. A statistical treatment of a collection of discrete current-vorticity concentrations is given. Canonical and microcanonical statistical calculations show that both the vorticity and the current spectra are peaked at long wavelengths, and the expected states revert to known hydrodynamical states as the magnetic field vanishes. These results differ from previous Fourier-based statistical theories, but it is found that when the filament calculation is expanded to include the inductive force, the results approach the Fourier equilibria in the low-temperature limit, and the previous Hamiltonian plasma vortex results in the high-temperature limit. Numerical simulations of a large number of filaments are carried out and support the theory. A three-dimensional vortex model is presented as well, which is also Hamiltonian when the inductive force is neglected. A statistical calculation in the canonical ensemble and numerical simulations show that a nonzero large-scale magnetic field is statistically favored, and that the preferred shape of this field is a long, thin tube of flux. Possible applications to a variety of physical phenomena are suggested

  13. Plasma physics and instabilities

    Lashmore-Davies, C.N.

    1981-01-01

    These lectures procide an introduction to the theory of plasmas and their instabilities. Starting from the Bogoliubov, Born, Green, Kirkwood, and Yvon (BBGKY) hierarchy of kinetic equations, the additional concept of self-consistent fields leads to the fundamental Vlasov equation and hence to the warm two-fluid model and the one-fluid MHD, or cold, model. The properties of small-amplitude waves in magnetized (and unmagnetized) plasmas, and the instabilities to which they give rise, are described in some detail, and a complete chapter is devoted to Landau damping. The linear theory of plasma instabilities is illustrated by the current-driven electrostatic kind, with descriptions of the Penrose criterion and the energy principle of ideal MHD. There is a brief account of the application of feedback control. The non-linear theory is represented by three examples: quasi-linear velocity-space instabilities, three-wave instabilities, and the stability of an arbitrarily largeamplitude wave in a plasma. (orig.)

  14. Plasma focus matching conditions

    Soliman, H.M.; Masoud, M.M.; Elkhalafawy, T.A.

    1988-01-01

    A snow-plough and slug models have been used to obtain the optimum matching conditions of the plasma in the focus. The dimensions of the plasma focus device are, inner electrode radius = 2 cm, outer electrode radius = 5.5 cm, and its length = 8 cm. It was found that the maximum magnetic energy of 12.26 kJ has to be delivered to plasma focus whose density is 10 19 /cm 3 at focusing time of 2.55 μs and with total external inductance of 24.2 n H. The same method is used to evaluate the optimum matching conditions for the previous coaxial discharge system which had inner electrode radius = 1.6 cm, outer electrode radius = 3.3 cm and its length = 31.5 cm. These conditions are charging voltage = 12 kV, capacity of the condenser bank = 430 μf, plasma focus density = 10 19 /cm 3 focusing time = 8 μs and total external inductance = 60.32 n H.3 fig., 2 tab

  15. Plasma deposition of refractories

    Kudinov, V.V.; Ivanov, V.M.

    1981-01-01

    The problems of deposition, testing and application of plasma coating of refractory metals and oxides are considered. The process fundamentals, various manufacturing procedures and equipment for their realization are described in detail. Coating materials are given (Al, Mg, Al 2 O 3 , ZrO 2 , MgAlO 4 ) which are used in reactor engineering and their designated purposes are shown [ru

  16. 5. Laser plasma interaction

    Labaune, C.; Fuchs, J.; Bandulet, H.

    2002-01-01

    Imprint elimination, smoothing and preheat control are considerable problems in inertial fusion and their possible solution can be achieved by using low-density porous materials as a buffer in target design. The articles gathered in this document present various aspects of the laser-plasma interaction, among which we have noticed: -) numerical algorithmic improvements of the Vlasov solver toward the simulation of the laser-plasma interaction are proposed, -) the dependence of radiation temperatures and X-ray conversion efficiencies of hohlraum on the target structures and laser irradiation conditions are investigated, -) a study of laser interaction with ultra low-density (0,5 - 20 mg/cm 3 ) porous media analyzing backscattered light at incident laser frequency ω 0 and its harmonics 3*ω 0 /2 and 2*ω 0 is presented, -) investigations of laser interaction with solid targets and crater formation are carried out with the objective to determine the ablation loading efficiency, -) a self organization in an intense laser-driven plasma and the measure of the relative degree of order of the states in an open system based on the S-theorem are investigated, and -) the existence and stability of electromagnetic solitons generated in a relativistic interaction of an intense laser light with uniform under-dense cold plasma are studied

  17. Fundamentals of plasma physics

    Bittencourt, J A

    1986-01-01

    A general introduction designed to present a comprehensive, logical and unified treatment of the fundamentals of plasma physics based on statistical kinetic theory. Its clarity and completeness make it suitable for self-learning and self-paced courses. Problems are included.

  18. Plasma source ion implantation

    Conrad, J.R.; Forest, C.

    1986-01-01

    The authors' technique allows the ion implantation to be performed directly within the ion source at higher currents without ion beam extraction and transport. The potential benefits include greatly increased production rates (factors of 10-1000) and the ability to implant non-planar targets without rastering or shadowing. The technique eliminates the ion extractor grid set, beam raster equipment, drift space and target manipulator equipment. The target to be implanted is placed directly within the plasma source and is biased to a large negative potential so that plasma ions gain energy as they accelerate through the potential drop across the sheath that forms at the plasma boundary. Because the sheath surrounds the target on all sides, all surfaces of the target are implanted without the necessity to raster the beam or to rotate the target. The authors have succeeded in implanting nitrogen ions in a silicon target to the depths and concentrations required for surface treatment of materials like stainless steel and titanium alloys. They have performed ESCA measurements of the penetration depth profile of a silicon target that was biased to 30 kV in a nitrogen discharge plasma. Nitrogen ions were implanted to a depth of 700A at a peak concentration of 30% atomic. The measured profile is quite similar to a previously obtained profile in titanium targets with conventional techniques

  19. Plasma skin regeneration technology.

    Bogle, M A

    2006-09-01

    Plasma skin regeneration (PSR) technology uses energy delivered from plasma rather than light or radiofrequency. Plasma is the fourth state of matter in which electrons are stripped from atoms to form an ionized gas. The plasma is emitted in a millisecond pulse to deliver energy to target tissue upon contact without reliance on skin chromophores. The technology can be used at varying energies for different depths of effect, from superficial epidermal sloughing to deeper dermal heating. With the Portrait PSR device (Rhytec, Inc.) there are three treatment guidelines termed PSR1, PSR2, and PSR3. The PSR1 protocol uses a series of low-energy treatments (1.0,1.2 Joules) spaced 3 weeks apart. The PSR2 protocol uses one high-energy pass (3.0, 4.0 Joules) performed in a single treatment, and the PSR3 protocol uses two high-energy passes (3.0 4.0 Joules) performed in a single treatment. All protocols improve fine lines, textural irregularities, and dyspigmentation; however, skin tightening is probably more pronounced with the high-energy treatments.

  20. Stirring Strongly Coupled Plasma

    Fadafan, Kazem Bitaghsir; Rajagopal, Krishna; Wiedemann, Urs Achim

    2009-01-01

    We determine the energy it takes to move a test quark along a circle of radius L with angular frequency w through the strongly coupled plasma of N=4 supersymmetric Yang-Mills (SYM) theory. We find that for most values of L and w the energy deposited by stirring the plasma in this way is governed either by the drag force acting on a test quark moving through the plasma in a straight line with speed v=Lw or by the energy radiated by a quark in circular motion in the absence of any plasma, whichever is larger. There is a continuous crossover from the drag-dominated regime to the radiation-dominated regime. In the crossover regime we find evidence for significant destructive interference between energy loss due to drag and that due to radiation as if in vacuum. The rotating quark thus serves as a model system in which the relative strength of, and interplay between, two different mechanisms of parton energy loss is accessible via a controlled classical gravity calculation. We close by speculating on the implicati...

  1. Reprocessing of spent plasma

    Pierini, G.

    1981-01-01

    This invention relates to a process for removing helium and other impurities from a mixture containing deuterium and tritium, a deuterium/tritium mixture when purified in accordance with such a process and, more particularly, to a process for the reprocessing of spent plasma removed from a thermofusion reactor. (U.K.)

  2. Planetary plasmas and fields

    Roederer, J.G.

    1976-01-01

    The magnetospheres of earth, Jupiter, and Mercury are discussed. The main features and physical processes characteristic of the quiet time earth magnetosphere are examined. Jupiter's larger and more distant magnetosphere is compared with the earth's and recent findings are reviewed. The plasma and field environment of Mercury is also discussed and similarities with the earth's magnetosphere are noted

  3. Implicit plasma simulation

    Langdon, A.B.

    1985-01-01

    Implicit time integration methods have been used extensively in numerical modelling of slowly varying phenomena in systems that also support rapid variation. Examples include diffusion, hydrodynamics and reaction kinetics. This article discussed implementation of implicit time integration in plasma codes of the ''particle-in-cell'' family, and the benefits to be gained

  4. Fundamentals of Plasma Physics

    Cargill, P J

    2007-01-01

    The widespread importance of plasmas in many areas of contemporary physics makes good textbooks in the field that are both introductory and comprehensive invaluable. This new book by Paul Bellen from CalTech by and large meets these goals. It covers the traditional textbook topics such as particle orbits, the derivation of the MHD equations from Vlasov theory, cold and warm plasma waves, Landau damping, as well as in the later chapters less common subjects such as magnetic helicity, nonlinear processes and dusty plasmas. The book is clearly written, neatly presented, and each chapter has a number of exercises or problems at their end. The author has also thankfully steered clear of the pitfall of filling the book with his own research results. The preface notes that the book is designed to provide an introduction to plasma physics for final year undergraduate and post-graduate students. However, it is difficult to see many physics undergraduates now at UK universities getting to grips with much of the content since their mathematics is not of a high enough standard. Students in Applied Mathematics departments would certainly fare better. An additional problem for the beginner is that some of the chapters do not lead the reader gently into a subject, but begin with quite advanced concepts. Being a multi-disciplinary subject, beginners tend to find plasma physics quite hard enough even when done simply. For postgraduate students these criticisms fade away and this book provides an excellent introduction. More senior researchers should also enjoy the book, especially Chapters 11-17 where more advanced topics are discussed. I found myself continually comparing the book with my favourite text for many years, 'The Physics of Plasmas' by T J M Boyd and J J Sanderson, reissued by Cambridge University Press in 2003. Researchers would want both books on their shelves, both for the different ways basic plasma physics is covered, and the diversity of more advanced topics. For

  5. Plasma Wave Electronic Terahertz Technology

    Shur, Michael

    2003-01-01

    Plasma waves are oscillations of electron density in time and space. In deep submicron field effect transistors plasma wave frequencies lie in the terahertz range and can be tuned by applied gate bias...

  6. Probing of flowing electron plasmas

    Himura, H.; Nakashima, C.; Saito, H.; Yoshida, Z.

    2001-01-01

    Probing of streaming electron plasmas with finite temperature is studied. For the first time, a current-voltage characteristic of an electric probe is measured in electron plasmas. Due to the fast flow of the electron plasmas, the characteristic curve spreads out significantly and exhibits a long tail. This feature can be explained calculating the currents collected to the probe. In flowing electron plasmas, the distribution function observed in the laboratory frame is non-Maxwellian even if the plasmas come to a state of thermal equilibrium. Another significant feature of the characteristic is that it determines a floating potential where the current equals zero, despite there being very few ions in the electron plasma. A high impedance probe, which is popularly used to determine the space potential of electron plasmas, outputs the potential. The method is available only for plasmas with density much smaller than the Brillouin limit

  7. High-frequency plasma oscillations

    Akhiezer, A I; Fainberg, Y B; Sitenko, A G; Stepanov, K; Kurilko, V; Gorbatenko, M; Kirochkin, U [Academy of Sciences of the Ukrainian SSR (USSR)

    1958-07-01

    It is well known that the electrical conductivity of a plasma, the ion-electron equilibration time, and the time required to heat the electron component of the plasma all increase greatly with increasing temperature. Consequently, the usual method of Joule heating a plasma may be difficult to apply in the region of high temperatures (> 10{sup 6}K), especially if the plasma current alone, without any additional measures, is used to generate magnetic fields for the confinement of the plasma. Therefore, it is of interest to study methods of plasma heating that do not directly use Joule heat, especially methods by which energy is directly supplied to the ion component during the time between collisions. Some of these methods make use of ionic resonance as well as other resonance phenomena which can occur in plasma in an external magnetic field. This paper deals with certain aspects of the theory of high-frequency plasma oscillations.

  8. Basic physics of colloidal plasmas

    Plasma Physics Division, Institute of Advanced Study in Science and Technology, Khanapara, ..... tic wave) to form a random collection of the nonlinear wave grains (like ... [8] M S Sodha and S Guha, in Advances in plasma phyiscs edited by A ...

  9. Plasma devices for hydrocarbon reformation

    Cha, Min

    2017-01-01

    Plasma devices for hydrocarbon reformation are provided. Methods of using the devices for hydrocarbon reformation are also provided. The devices can include a liquid container to receive a hydrocarbon source, and a plasma torch configured

  10. Water-stabilized plasma generators

    Hrabovský, Milan

    1998-01-01

    Roč. 70, č. 6 (1998), s. 1157-1162 ISSN 0033-4545 R&D Projects: GA ČR GA102/95/0592; GA ČR GV106/96/K245 Institutional research plan: CEZ:AV0Z2043910 Keywords : thermal plasma, plasma torch, water-stabilized plasma Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.677, year: 1998

  11. Controlled fusion and plasma heating

    1990-06-01

    The contributions presented in the 17th European Conference on Controlled Fusion and Plasma Heating were focused on Tore Supra investigations. The following subjects were presented: ohmic discharges, lower hybrid experiments, runaway electrons, Thomson scattering, plasma density measurements, magnetic fluctuations, polarization scattering, plasma currents, plasma fluctuation measurements, evaporation of hydrogen pellets in presence of fast electrons, ripple induced stochastic diffusion of trapped particles, tearing mode stabilization, edge effects on turbulence behavior, electron cyclotron heating, micro-tearing modes, divertors, limiters

  12. Information Theory and Plasma Turbulence

    Dendy, R. O.

    2009-01-01

    Information theory, applied directly to measured signals, yields new perspectives on, and quantitative knowledge of, the physics of strongly nonlinear and turbulent phenomena in plasmas. It represents a new and productive element of the topical research programmes that use modern techniques to characterise strongly nonlinear signals from plasmas, and that address global plasma behaviour from a complex systems perspective. We here review some pioneering studies of mutual information in solar wind and magnetospheric plasmas, using techniques tested on standard complex systems.

  13. Transition in plasma fluctuation between attached and detached plasmas

    Okazaki, Katsuya; Ohno, Noriyasu; Kajita, Shin; Tanaka, Hirohiko

    2012-01-01

    The static and dynamic behaviors of detached plasmas have received considerable attention because the use of a detached divertor is thought to provide a promising method for reducing the heat flux to plasma-facing components. In this study, fluctuations were measured with an electrostatic probe as the plasma was changed from attached to detached states by increasing the neutral gas pressure. The transition from an attached plasma to a detached plasma was found to change the phase relation between the density and the potential. (author)

  14. Plasma simulation in space propulsion : the helicon plasma thruster

    Navarro Cavallé, Jaume

    2017-01-01

    The Helicon Plasma Thruster (HPT) is an electrodynamic rocket proposed in the early 2000s. It matches an Helicon Plasma Source (HPS), which ionizes the neutral gas and heats up the plasma, with aMagneticNozzle (MN),where the plasma is supersonically accelerated resulting in thrust. Although the core of this thruster inherits the knowledge on Helicon Plasma sources, dated from the seventies, the HPT technology is still not developed and remains below TRL 4. A deep review of the HPT State-of-ar...

  15. Dusty plasma phase in a steady state plasma device

    Liang Xiaoping; Zheng Jian; Ma Jinxiu; Liu Wangdong; Zhuang Ge; Xie Jinlin; Wang Congrong; Yu Changxuan

    2000-01-01

    A DC discharge dusty plasma device used for study of waves in dusty plasma is introduced. A dusty plasma column is produced with about 30 cm in length and about 8.4 cm in diameter. The electron saturation current of Langmuir probe is obviously decreasing while the dust grains are present in the plasma. The negative charge on dust grains is directly proportional to the rotation rate of the dispenser. And the dust grains carry up to 40% of the negative charges in the whole plasma

  16. Gas injected washer plasma gun

    Jain, K.K.; John, P.I.; Punithavelu, A.M.; Rao, P.P.

    1980-01-01

    A plasma gun similar in geometry to the washer plasma gun has been operated with gas injected externally. hydrogen, nitrogen and argon plasmas have been ionised and accelerated to velocities of the order of 10 7 mm s -1 and densities 10 11 mm -3 . Higher parameter range is possible with higher electrical input power. (author)

  17. High-temperature plasma physics

    Furth, H.P.

    1988-03-01

    Both magnetic and inertial confinement research are entering the plasma parameter range of fusion reactor interest. This paper reviews the individual and common technical problems of these two approaches to the generation of thermonuclear plasmas, and describes some related applications of high-temperature plasma physics

  18. Plasma Physics Applied (New Book)

    Grabbe, Crockett

    2007-03-01

    0.5cm Plasma physics applications are one of the most rapidly growing fields in engineering & applied science today. The last decade alone has seen the rapid emergence of new applications such as dusty plasmas in the semiconductor and microchip industries, and plasma TVs. In addition, this last decade saw the achievement of the 50-year Lawson breakeven condition for fusion. With new discoveries in space plasma physics and applications to spacecraft for worldwide communication and space weather, as well as new applications being discovered, this diversity is always expanding. The new book Plasma Physics Applied reviews developments in several of these areas. Chapter 1 reviews the content and its authors, and is followed by a more comprehensive review of plasma physics applications in general in Chapter 2. Plasma applications in combustion and environmental uses are presented in Chapter 3. Lightning effects in planetary magnetospheres and potential application are described in Chapter 4. The area of dusty plasmas in both industrial and space plasmas and their applications are reviewed in Chapter 5. The particular area of Coulomb clusters in dusty plasmas is presented in Chapter 6. The variety of approaches to plasma confinement in magnetic devices for fusion are laid out in Chapter 7. Finally, an overview of plasma accelerator developments and their applications are presented in Chapter 8.

  19. Introduction to dusty plasma physics

    Shukla, PK

    2001-01-01

    Introduction to Dusty Plasma Physics contains a detailed description of the occurrence of dusty plasmas in our Solar System, the Earth''s mesosphere, and in laboratory discharges. The book illustrates numerous mechanisms for charging dust particles and provides studies of the grain dynamics under the influence of forces that are common in dusty plasma environments.

  20. Elements of plasma kinetic theory

    Guasp, J.

    1976-01-01

    The physical foundations of plasma kinetic equations are exposed inside a series of seminars on plasma and fusion physics. The Vlasov and collisional equations with its application range have been discussed. The momenta equations for the macroscopic magnitudes and the more usual approximations have been obtained: two fluid equations for cold and warm plasmas, magnetohydrodynamic equations and the double-adiabatic theory. (author)

  1. Optical properties of dense plasmas

    Guenther, S.

    1996-05-01

    The following topics were dealt with: Stellar spectra and stellar atmospheres, spectrocopic methods in the plasma diagnostic, Green function method, influence of charged plasma particles on the line profile, Storer-Strahler interaction, dynamic screening effects, line profile shift and asymmetry, collective plasma excitations, ion dynamic effects on line profiles

  2. Containment of high temperature plasmas

    Bass, R.W.; Ferguson, H.R.P.; Fletcher, H. Jr.; Gardner, J.; Harrison, B.K.; Larsen, K.M.

    1973-01-01

    Apparatus is described for confining a high temperature plasma which comprises: 1) envelope means shaped to form a toroidal hollow chamber containing a plasma, 2) magnetic field line generating means for confining the plasma in a smooth toroidal shape without cusps. (R.L.)

  3. Large-scale numerical simulations of plasmas

    Hamaguchi, Satoshi

    2004-01-01

    The recent trend of large scales simulations of fusion plasma and processing plasmas is briefly summarized. Many advanced simulation techniques have been developed for fusion plasmas and some of these techniques are now applied to analyses of processing plasmas. (author)

  4. Miniature Coaxial Plasma injector Diagnostics by Beam Plasma Interaction

    El-Tayeb, H.; El-Gamal, H.

    2003-01-01

    A miniature coaxial gun has been used to study the interaction between plasma beam and low density plasma formed in glow discharge. The peak discharge current flow between the coaxial electrodes was 5.25 kA as a single pulse with pulse width of 60 mu. Investigations are carried out with argon gas at pressure 0.4 Torr. The plasma stream ejected from the coaxial discharge propagates in the neutral argon atoms with mean velocity of 1.2x10 5 cm/s. The plasma stream temperature and density were 4.2 eV and 2.4x10 13 cm -3 respectively. An argon negative glow has been used as base plasma where its electron temperature and density were 2.2 eV and 6.2x10 7 cm -3 respectively. When the plasma stream propagates through the negative glow discharge region its velocity decreased to 8.8 x 10 4 cm/s and also the plasma electron temperature decreased to 3.1 eV, while the stream density remained the same. An excited wave appeared on the electric probe having frequency equal to the plasma frequency of the plasma under consideration. Simulation of the problem showed that this method could be applied for plasma diagnostics within the region of investigation. Those further studies for high temperature, dense, and magnetized plasma will be considered

  5. Streaming metal plasma generation by vacuum arc plasma guns

    MacGill, R.A.; Dickinson, M.R.; Anders, A.; Monteiro, O.R.; Brown, I.G.

    1998-01-01

    We have developed several different embodiments of repetitively pulsed vacuum arc metal plasma gun, including miniature versions, multicathode versions that can produce up to 18 different metal plasma species between which one can switch, and a compact high-duty cycle well-cooled version, as well as a larger dc gun. Plasma guns of this kind can be incorporated into a vacuum arc ion source for the production of high-energy metal ion beams, or used as a plasma source for thin film formation and for metal plasma immersion ion implantation and deposition. The source can also be viewed as a low-energy metal ion source with ion drift velocity in the range 20 - 200 eV depending on the metal species used. Here we describe the plasma sources that we have developed, the properties of the plasma generated, and summarize their performance and limitations. copyright 1998 American Institute of Physics

  6. The Plasma Archipelago: Plasma Physics in the 1960s

    Weisel, Gary J.

    2017-09-01

    With the foundation of the Division of Plasma Physics of the American Physical Society in April 1959, plasma physics was presented as the general study of ionized gases. This paper investigates the degree to which plasma physics, during its first decade, established a community of interrelated specialties, one that brought together work in gaseous electronics, astrophysics, controlled thermonuclear fusion, space science, and aerospace engineering. It finds that, in some regards, the plasma community was indeed greater than the sum of its parts and that its larger identity was sometimes glimpsed in inter-specialty work and studies of fundamental plasma behaviors. Nevertheless, the plasma specialties usually worked separately for two inter-related reasons: prejudices about what constituted "basic physics," both in the general physics community and within the plasma community itself; and a compartmentalized funding structure, in which each funding agency served different missions.

  7. Scattering of electromagnetic waves into plasma oscillations via plasma particles

    Lin, A.T.; Dawson, J.M.

    1975-01-01

    A plasma subjected to an intense electromagnetic wave can exhibit a large number of parametric instabilities. An interesting example which has received little attention is the decay of the electromagnetic wave into a plasma oscillation with the excess energy and momentum being carried off by electrons. This process has been simulated on a one-and-two-halves dimensional electromagnetic code. The incident electromagnetic wave had a frequency near the plasma frequency so that decay into a plasma oscillation and a backscattered electromagnetic wave was excluded. As expected, the threshold for this instability was very large , so it is unlikely that this instability is competitive in most laser plasmas. Nevertheless, the physical mechanism involved provides a means for absorption of laser light and acceleration of particles in a plasma containing large amplitude plasma oscillations

  8. Merging and Splitting of Plasma Spheroids in a Dusty Plasma

    Mikikian, Maxime; Tawidian, Hagop; Lecas, Thomas

    2012-12-01

    Dust particle growth in a plasma is a strongly disturbing phenomenon for the plasma equilibrium. It can induce many different types of low-frequency instabilities that can be experimentally observed, especially using high-speed imaging. A spectacular case has been observed in a krypton plasma where a huge density of dust particles is grown by material sputtering. The instability consists of well-defined regions of enhanced optical emission that emerge from the electrode vicinity and propagate towards the discharge center. These plasma spheroids have complex motions resulting from their mutual interaction that can also lead to the merging of two plasma spheroids into a single one. The reverse situation is also observed with the splitting of a plasma spheroid into two parts. These results are presented for the first time and reveal new behaviors in dusty plasmas.

  9. Interaction between electromagnetic waves and plasma waves in motional plasma

    Chen, S. Y.; Gao, M.; Tang, C. J.; Peng, X. D.

    2009-01-01

    The electromagnetic wave (EM wave) behavior and the electromagnetic instability caused by the interaction between an EM wave and a plasma wave in motional plasma are studied. The dispersion relation of EM waves and the dielectric tensor of motional plasma are derived by magnetohydrodynamics, and the wave phenomenon in motional plasma is displayed. As a result, the electromagnetic instability, which is excited by the interaction between the EM waves and the plasma waves, is revealed. The mechanism of the instability is the coupling between high frequency electromagnetic field and the transverse electron oscillation derived from the deflection of longitudinal electron oscillation due to self-magnetic field. The present research is useful with regard to the new type of plasma radiation source, ion-focusing accelerator, and plasma diagnostic technique.

  10. High beta plasma operation in a toroidal plasma producing device

    Clarke, J.F.

    1978-01-01

    A high beta plasma is produced in a plasma producing device of toroidal configuration by ohmic heating and auxiliary heating. The plasma pressure is continuously monitored and used in a control system to program the current in the poloidal field windings. Throughout the heating process, magnetic flux is conserved inside the plasma and the distortion of the flux surfaces drives a current in the plasma. As a consequence, the total current increases and the poloidal field windings are driven with an equal and opposing increasing current. The spatial distribution of the current in the poloidal field windings is determined by the plasma pressure. Plasma equilibrium is maintained thereby, and high temperature, high beta operation results

  11. Synthesis of N-graphene using microwave plasma-based methods

    Dias, Ana; Tatarova, Elena; Henriques, Julio; Dias, Francisco; Felizardo, Edgar; Abrashev, Miroslav; Bundaleski, Nenad; Cvelbar, Uros

    2016-09-01

    In this work a microwave atmospheric plasma driven by surface waves is used to produce free-standing graphene sheets (FSG). Carbonaceous precursors are injected into a microwave plasma environment, where decomposition processes take place. The transport of plasma generated gas-phase carbon atoms and molecules into colder zones of plasma reactor results in carbon nuclei formation. The main part of the solid carbon is gradually carried from the ``hot'' plasma zone into the outlet plasma stream where carbon nanostructures assemble and grow. Subsequently, the graphene sheets have been N-doped using a N2-Ar large-scale remote plasma treatment, which consists on placing the FSG on a substrate in a remote zone of the N2-Ar plasma. The samples were treated with different compositions of N2-Ar gas mixtures, while maintaining 1 mbar pressure in the chamber and a power applied of 600 W. The N-doped graphene sheets were characterized by scanning and by high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Plasma characterization was also performed by optical emission spectroscopy. Work partially funded by Portuguese FCT - Fundacao para a Ciencia e a Tecnologia, under grant SFRH/BD/52413/2013 (PD-F APPLAuSE).

  12. MODELO PARA LA CREACIÓN DEL CONOCIMIENTO PARA PYMES

    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.

  13. Experimental Plasma Research project summaries

    1980-09-01

    This report contains descriptions of the activities supported by the Experimental Plasma Research Branch of APP. The individual project summaries were prepared by the principal investigators and include objectives and milestones for each project. The projects are arranged in six research categories: Plasma Properties; Plasma Heating; Plasma Diagnostics; Atomic, Molecular and Nuclear Physics; Advanced Superconducting Materials; and the Fusion Plasma Research Facility (FPRF). Each category is introduced with a statement of objectives and recent progress and followed by descriptions of individual projects. An overall budget summary is provided at the beginning of the report

  14. Plasma expansion: fundamentals and applications

    Engeln, R; Mazouffre, S; Vankan, P; Bakker, I; Schram, D C

    2002-01-01

    The study of plasma expansion is interesting from a fundamental point of view as well as from a more applied point of view. We here give a short overview of the way properties like density, velocity and temperature behave in an expanding thermal plasma. Experimental data show that the basic phenomena of plasma expansion are to some extent similar to those of the expansion of a hot neutral gas. From the application point of view, we present first results on the use of an expanding thermal plasma in the plasma-activated catalysis of ammonia, from N 2 -H 2 mixtures

  15. Atmospheric-pressure plasma technology

    Kogelschatz, U

    2004-01-01

    Major industrial plasma processes operating close to atmospheric pressure are discussed. Applications of thermal plasmas include electric arc furnaces and plasma torches for generation of powders, for spraying refractory materials, for cutting and welding and for destruction of hazardous waste. Other applications include miniature circuit breakers and electrical discharge machining. Non-equilibrium cold plasmas at atmospheric pressure are obtained in corona discharges used in electrostatic precipitators and in dielectric-barrier discharges used for generation of ozone, for pollution control and for surface treatment. More recent applications include UV excimer lamps, mercury-free fluorescent lamps and flat plasma displays

  16. Tecnical report- Group of Plasma

    Sakanaka, P.H.; Boeckelmann, H.K.; Marotta, A.

    1985-01-01

    The research activities of Plasma Laboratory at UNICAMP (University of Campinas, Brazil) in the period from november 84 to july/85 are described. In the TUPA project, several works related to substructure and research programs were developed. Diagnostic techniques to analyse the theta Pinch implosion phase, a presure probe, an electrostatic ion energy analyser and laser-produced plasma spectroscopy were developed. The experimental results were obtained, using multiple magnetic probes inserted in the plasma. These results were analysed by numerical code using some MHD equations in 2 dimensions. A description of plasma dynamic was determined and the plasma parameters such as density and temperature were estimated. (M.C.K.) [pt

  17. Plasma devices for hydrocarbon reformation

    Cha, Min Suk

    2017-02-16

    Plasma devices for hydrocarbon reformation are provided. Methods of using the devices for hydrocarbon reformation are also provided. The devices can include a liquid container to receive a hydrocarbon source, and a plasma torch configured to be submerged in the liquid. The plasma plume from the plasma torch can cause reformation of the hydrocarbon. The device can use a variety of plasma torches that can be arranged in a variety of positions in the liquid container. The devices can be used for the reformation of gaseous hydrocarbons and/or liquid hydrocarbons. The reformation can produce methane, lower hydrocarbons, higher hydrocarbons, hydrogen gas, water, carbon dioxide, carbon monoxide, or a combination thereof.

  18. Experimental plasma research project summaries

    1978-08-01

    This report contans descriptions of the activities supported by the Experimental Plasma Research Branch of APP. The individual project summaries were prepared by the principal investigators and include objectives and milestones for each project. The projects are arranged in six research categories: Plasma Properties; Plasma Heating; Plasma Measurements and Instrumentation; Atomic, Molecular and Nuclear Physics; Advanced Superconducting Materials; and the Fusion Plasma Research Facility (FPRF). Each category is introduced with a statement of objectives and recent progress and followed by descriptions of individual projects. An overall budget summary is provided at the beginning of the report

  19. Experimental Plasma Research project summaries

    None

    1980-09-01

    This report contains descriptions of the activities supported by the Experimental Plasma Research Branch of APP. The individual project summaries were prepared by the principal investigators and include objectives and milestones for each project. The projects are arranged in six research categories: Plasma Properties; Plasma Heating; Plasma Diagnostics; Atomic, Molecular and Nuclear Physics; Advanced Superconducting Materials; and the Fusion Plasma Research Facility (FPRF). Each category is introduced with a statement of objectives and recent progress and followed by descriptions of individual projects. An overall budget summary is provided at the beginning of the report.

  20. Plasmas and intense laser light

    Kennedy, E.T.

    1984-01-01

    The present article begins with a description of the laser technology required to reach the high irradiances of interest and provides a brief outline of the more important diagnostic techniques used in investigating the plasmas. An introduction to plasma waves is given and the linear and nonlinear excitation of waves is discussed. The remainder of the article describes some of the experimental evidence supporting the interpretation of the plasma behaviour at high laser-light intensities in terms of the excitation of plasma waves and the subsequent heating of plasma by these waves. (author)

  1. Waves and Oscillations in Plasmas

    Pecseli, Hans L

    2012-01-01

    The result of more than 15 years of lectures in plasma sciences presented at universities in Denmark, Norway, and the United States, Waves and Oscillations in Plasmas addresses central issues in modern plasma sciences. The book covers fluid models as well as kinetic plasma models, including a detailed discussion of, for instance, collisionless Landau damping. Offering a clear separation of linear and nonlinear models, the book can be tailored for readers of varying levels of expertise.Designed to provide basic training in linear as well as nonlinear plasma dynamics, and practical in areas as d

  2. Coccocypselum pulchellum (Rubiaceae, nuevo registro para Argentina

    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.

  3. Adiabatic plasma buncher

    Ferrario, M. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, Frascati, RM (Italy); Katsouleas, T.C. [Los Angeles Univ. of Southern California, Los Angeles, CA (United States); Serafini, L. [Istituto Nazionale di Fisica Nucleare, Milan (Italy); Ben Zvi, I. [Brookhaven National Laboratory, Upton, NY (United States)

    2000-07-01

    In this paper is presented a new scheme of injection into a plasma accelerator, aimed at producing a high quality beam while relaxing the demands on the bunch length of the injected beam. The beam dynamics in the injector, consisting of a high voltage pulsed photo-diode, is analyzed and optimized to produce a {lambda}{sub p}/20 long electron bunch at 2.5 MeV. This bunch is injected into a plasma wave in which it compresses down to {lambda}{sub p}/100 while simultaneously accelerating up to 250 MeV. This simultaneous bunching and acceleration of a high quality beam requires a proper combination of injection energy and injection phase. Preliminary results from simulations are shown to assess the potentials of the scheme.

  4. Magnetospheric plasma physics

    Bingham, R.

    1989-09-01

    The discovery of the earth's radiation belts in 1957 by Van Allen marked the beginning of what is now known as magnetospheric physics. In this study of plasma physics in the magnetosphere, we shall take the magnetosphere to be that part of the earth's ionized atmosphere which is formed by the interaction of the solar wind with the earth's dipole-like magnetic field. It extends from approximately 100km above the earth's surface where the proton-neutral atom collision frequency is equal to the proton gyrofrequency to about ten earth radii (R E ∼ 6380km) in the sunward direction and to several hundred earth radii in the anti-sunward direction. The collision dominated region is called the ionosphere and is sometimes considered separate from the collisionless plasma region. In the ionosphere ion-neutral collisions are dominant and one may think of the ionosphere as a frictional boundary layer ∼ 1000km thick. Other planets are also considered. (author)

  5. Underwater plasma arc cutting

    Leautier, R.; Pilot, G.

    1991-01-01

    This report describes the work done to develop underwater plasma arc cutting techniques, to characterise aerosols from cutting operations on radioactive and non-radioactive work-pieces, and to develop suitable ventilation and filtration techniques. The work has been carried out in the framework of a contract between CEA-CEN Cadarache and the Commission of European Communities. Furthermore, this work has been carried out in close cooperation with CEA-CEN Saclay mainly for secondary emissions and radioactive analysis. The contract started in May 1986 and was completed in December 1988 by a supplementary agreement. This report has been compiled from several progress reports submitted during the work period, contains the main findings of the work and encloses the results of comparative tests on plasma arc cutting

  6. Plasma and the universe

    Falthammar, C.G.

    1988-01-01

    Hannes Alfven has enjoyed a long and spectacular career in which he has time and again pioneered the path that other workers were able fruitfully to exploit. One thinks of the Alven waves, the concept of gyrocenter drift and the perturbation theory based on it, and the critical velocity phenomenon in the interaction of a plasma with a neutral gas. All of these discoveries have been of fundamental importance. By no means content to rest on his laurels, Alfven has, during the last decade, contributed to science in a major sense, especially in the field of cosmogeny. For example, he has used the latest data from the Voyager spacecraft to test his detailed predictions of the structure of the Saturnian rings. Alfven's current preoccupation is with the Plasma Universe and, as may be expected, some of his concepts are receiving observational support, while others are still controversial

  7. Magnetron plasma and nanotechnology

    Kashtanov, Pavel V; Smirnov, Boris M; Hippler, Rainer

    2007-01-01

    Magnetron plasma processes involving metal atoms and clusters are reviewed. The formation of metal atoms near the cathode and their nucleation in a buffer gas flow are discussed. The flow of a buffer gas with metal clusters through a magnetron chamber disturbs the equilibrium between the buffer gas flow and clusters near the exit orifice and is accompanied by cluster attachment to the chamber walls. Cluster charging far off the cathode, the disturbance of equilibrium between the buffer gas flow and cluster drift, and the attachment of charged clusters to the chamber walls - the factors determining the output parameters of the cluster beam escaping the magnetron chamber - are analyzed. Cluster deposition on a solid surface and on dusty plasma particles is considered. (reviews of topical problems)

  8. Estimating plasma temperatures

    Nash, J.K.; Iglesias, C.A.; Chen, M.H.; Rogers, F.J.

    1992-04-01

    Recent laser-produced plasma experiments have relied on spectroscopic comparisons with models to infer plasma temperatures. The models use an experimentally determined value for the matter density as input and treat the temperature as a free parameter to obtain a best fit to the experimental absorption spectrum. However, uncertainties in the ionization balance theories lead to inferred temperatures that are model dependent. We report results of a new approach which combines high=quality atomic data with an ionization balance obtained from systematic expansions of the grand canonical ensemble. The latter avoids the ad hoc cutoffs required in free energy minimization schemes and includes Coulomb corrections usually neglected in other models. Comparisons to experimental spectra show excellent agreement

  9. Ion plasma electron gun

    Wakalopulos, G.

    1976-01-01

    In the disclosed electron gun positive ions generated by a hollow cathode plasma discharge in a first chamber are accelerated through control and shield grids into a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode causing the cathode to emit secondary electrons which form an electron beam having a distribution adjacent to the cathode emissive surface substantially the same as the distribution of the ion beam impinging upon the cathode. After passing through the grids and the plasma discharge chamber, the electron beam exits from the electron gun via a foil window. Control of the generated electron beam is achieved by applying a relatively low control voltage between the control grid and the electron gun housing (which resides at ground potential) to control the density of the positive ions bombarding the cathode

  10. Plasma Theory Division

    Callen, J.D.; Dory, R.A.; Aghevli, R.

    1977-01-01

    The progress during the past year is organized by group efforts and divided into five major areas. The basic tokamak areas and the sections in which their work is summarized are: magnetohydrodynamic (MHD) theory, kinetic theory, and transport simulation. The ELMO Bumpy Torus (EBT) theory work has its own research projects on MHD theory, kinetic theory, and transport simulation. In the plasma engineering area, relevant research work is further developed and synthesized into models that are used in the design of advanced fusion systems--The Next Step (TNS), demonstration fusion reactor (Demo), EBT ignition test, etc. Specific plasma engineering projects on providing the TNS physics basis and the development of the EBT reactor study are discussed. The computing support activities during the past year are summarized

  11. Electron waves and resonances in bounded plasmas

    Vandenplas, Paul E

    1968-01-01

    General theoretical methods and experimental techniques ; the uniform plasma slab-condenser system ; the hollow cylindrical plasma ; scattering of a plane electromagnetic wave by a plasma column in steady magnetic fields (cold plasma approximation) ; hot non-uniform plasma column ; metallic and dielectric resonance probes, plasma-dielectric coated antenna, general considerations.

  12. FRANQUICIAS. Una Alternativa para Emprendedores

    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.

  13. Transport processes in space plasmas

    Birn, J.; Elphic, R.C.; Feldman, W.C.

    1997-01-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project represents a comprehensive research effort to study plasma and field transport processes relevant for solar-terrestrial interaction, involving the solar wind and imbedded magnetic field and plasma structures, the bow shock of the Earth's magnetosphere and associated waves, the Earth's magnetopause with imbedded flux rope structures and their connection with the Earth, plasma flow in the Earth's magnetotail, and ionospheric beam/wave interactions. The focus of the work was on the interaction between plasma and magnetic and electric fields in the regions where different plasma populations exist adjacent to or superposed on each other. These are the regions of particularly dynamic plasma behavior, important for plasma and energy transport and rapid energy releases. The research addressed questions about how this interaction takes place, what waves, instabilities, and particle/field interactions are involved, how the penetration of plasma and energy through characteristic boundaries takes place, and how the characteristic properties of the plasmas and fields of the different populations influence each other on different spatial and temporal scales. These topics were investigated through combining efforts in the analysis of plasma and field data obtained through space missions with theory and computer simulations of the plasma behavior

  14. Plasma turbulence calculations on supercomputers

    Carreras, B.A.; Charlton, L.A.; Dominguez, N.; Drake, J.B.; Garcia, L.; Leboeuf, J.N.; Lee, D.K.; Lynch, V.E.; Sidikman, K.

    1991-01-01

    Although the single-particle picture of magnetic confinement is helpful in understanding some basic physics of plasma confinement, it does not give a full description. Collective effects dominate plasma behavior. Any analysis of plasma confinement requires a self-consistent treatment of the particles and fields. The general picture is further complicated because the plasma, in general, is turbulent. The study of fluid turbulence is a rather complex field by itself. In addition to the difficulties of classical fluid turbulence, plasma turbulence studies face the problems caused by the induced magnetic turbulence, which couples field by itself. In addition to the difficulties of classical fluid turbulence, plasma turbulence studies face the problems caused by the induced magnetic turbulence, which couples back to the fluid. Since the fluid is not a perfect conductor, this turbulence can lead to changes in the topology of the magnetic field structure, causing the magnetic field lines to wander radially. Because the plasma fluid flows along field lines, they carry the particles with them, and this enhances the losses caused by collisions. The changes in topology are critical for the plasma confinement. The study of plasma turbulence and the concomitant transport is a challenging problem. Because of the importance of solving the plasma turbulence problem for controlled thermonuclear research, the high complexity of the problem, and the necessity of attacking the problem with supercomputers, the study of plasma turbulence in magnetic confinement devices is a Grand Challenge problem

  15. Spectroscopic diagnostics of industrial plasmas

    Joshi, N.K.

    2004-01-01

    Plasmas play key role in modern industry and are being used for processing micro electronic circuits to the destruction of toxic waste. Characterization of industrial plasmas which includes both 'thermal plasmas' and non-equilibrium plasmas or 'cold plasmas' in industrial environment offers quite a challenge. Numerous diagnostic techniques have been developed for the measurement of these partially ionized plasma and/or particulate parameters. The 'simple' non-invasive spectroscopic methods for characterization of industrial plasmas will be discussed in detail in this paper. The excitation temperature in thermal (DC/RF) plasma jets has been determined using atomic Boltzmann technique. The central axis temperature of thermal plasma jets in a spray torch can be determined using modified atomic Boltzmann technique with out using Abel inversion. The Stark broadening of H β and Ar-I (430 nm) lines have been used to determine the electron number density in thermal plasma jets. In low-pressure non-equilibrium argon plasma, electron temperature has been measured using the Corona model from the ratio of line intensities of atomic and ionic transitions. (author)

  16. On neutral plasma oscillations

    Shadwick, B.A.; Morrison, P.J.

    1993-06-01

    We examine the conditions for the existence of spectrally stable neutral modes in a Vlasov-Poisson plasma and show that for stable equilibria of systems that have unbounded spatial domain, the only possible neutral modes are those with phase velocities that correspond to stationary inflection points of the equilibrium distribution function. It is seen that these neutral modes can possess positive or negative free energy

  17. Princeton Plasma Physics Laboratory:

    Phillips, C.A. (ed.)

    1986-01-01

    This paper discusses progress on experiments at the Princeton Plasma Physics Laboratory. The projects and areas discussed are: Principal Parameters Achieved in Experimental Devices, Tokamak Fusion Test Reactor, Princeton Large Torus, Princeton Beta Experiment, S-1 Spheromak, Current-Drive Experiment, X-ray Laser Studies, Theoretical Division, Tokamak Modeling, Spacecraft Glow Experiment, Compact Ignition Tokamak, Engineering Department, Project Planning and Safety Office, Quality Assurance and Reliability, and Administrative Operations.

  18. Topics in Plasma Physics

    Vahala, Linda [Old Dominion Univ., Norfolk, VA (United States)

    2015-05-31

    During the period 1998-2013, research under the auspices of the Department of Energy was performed on RF waves in plasmas. This research was performed in close collaboration with Josef Preinhaelter, Jakub Urban, Vladimir Fuchs, Pavol Pavlo and Frantisek Zacek (Czech Academy of Sciences), Martin Valovic and Vladimir Shevchenko (Culham). This research is detailed and all 38 papers which were published by this team are cited.

  19. Quark-Gluon Plasma

    1990-01-01

    This volume contains 14 review articles on the theory and phenomenology of the creation and diagnosis of quark-gluon plasma. They are written by active investigators of in the various research topics, which range from the QCD foundation through transport theory and thermalization models to the examination of possible signatures. The monograph should be useful not only to the experienced researchers in the subject but also to newcomers.

  20. Magnetized plasma kinetic theory

    Hassan, M.H.A.; Watson, C.J.H.

    1977-01-01

    The magnetized Balescu-Lenard Collision integral for a multi-species plasma in the form derived by Hassan and Watson (1976) is approximated by ignoring wave effects. The resulting collision integral is put in Fokker-Planck form and most of the integrals occurring in the coefficients are performed analytically. The remaining integral is evaluated approximately in various limits for ion-electron, electron-electron and electron-ion interactions. (author)