Efeito da barreira t?rmica em uma palheta de a?o AISI 316 utilizada para turbina a g?s.

Programa de P?s-Gradua??o em Engenharia de Materiais. Departamento de Engenharia Metal?rgica, Escola de Minas, Universidade Federal de Ouro Preto.O objetivo deste trabalho ? analisar uma palheta de turbina a g?s constitu?da de a?o inoxid?vel austen?tico (AISI 316), um sistema de resfriamento simples e um sistema de prote??o t?rmica, este formado por uma camada de zirc?nia estabilizada com ?tria e uma camada de liga??o formada de n?quel, cromo, alum?nio e ?trio. Estes sistemas s?o inclu?dos no projeto da palheta a fim de aumentar sua vida ?til e reduzir a temperatura do material base. Assim se pode aumentar a temperatura de entrada e o desempenho da turbina. Essa an?lise ? executada de duas formas, a primeira numericamente atrav?s da aplica??o da din?mica dos fluidos computacional (computational fluid dynamics ? CFD) e do m?todo dos elementos finitos na an?lise estrutural e outra experimentalmente atrav?s da constru??o de uma palheta e investiga??o do comportamento da barreira t?rmica em um forno de fluxo. Desta forma, avalia-se o comportamento do sistema em um fluxo oxidante de alta temperatura. Verifica-se tamb?m a efic?cia do revestimento no a?o inoxid?vel austen?tico, avaliando-se a temperatura interna da palheta, ou seja, a temperatura do metal. Assim, pode-se estimar a vida ?til da palheta. Igualmente, pode-se avaliar a hip?tese de que ligas menos nobres possuem uma vida ?til pr?xima das superligas utilizadas atualmente. Desta maneira, o custo na manufatura deste tipo de pe?a ser? reduzido. O estudo indica que o revestimento t?rmico e o sistema de resfriamento foram eficiente e reduziram significantemente a temperatura do substrato met?lico, redu??o da ordem de 300?C em rela??o a temperatura de entrada na turbina. Entretanto, o revestimento n?o suportou o fluxo oxidante, ocorrendo a gera??o de uma camada de ?xido no a?o inoxid?vel, assim deteriorando o revestimento.The objective of this work is to analyze a gas turbine blade made of austenitic stainless steel (AISI 316), a simple cooling system and a thermal barrier coating, this formed by a yttriastabilized zirconia layer and a bonding layer formed of nickel, chromium, aluminum and yttrium. These systems are included in the design of the blade in order to increase its useful life and reduce the temperature of the stainless steel. This can increase the turbine inlet temperature and turbine performance. This analysis is performed in two ways, the first numerically through the application of computational fluid dynamics (CFD) and finite volume method and another through an experiment with the construction of a blade and investigation of the thermal barrier behavior in an oven. In this way, the system behavior in a high temperature oxidizing flow is evaluated. The coating effectiveness on the austenitic stainless steel is also checked, the blade internal temperature, i.e. the temperature of the metal, is evaluated. Then, the blade life can be estimated. Thus, the hypothesis that less noble alloys have a useful life close to the superalloys can be evaluated. In this way, the manufacturing cost will be reduced. The study indicated that the thermal barrier coating and the cooling system were efficient and significantly reduced the temperature of the metal substrate, reducing the order of 300 ?C related to the turbine inlet temperature. However, the coating did not withstand the oxidizing flux, generating an oxide layer on the stainless steel surface, thus the coating was deteriorated

ANÁLISE DO DESEMPENHO DE UMA TURBINA A GÁS AERONÁUTICA DO TIPO TURBOFAN

Resumo:  O presente artigo tem como objetivo analisar os parâmetros de desempenho e consumo de combustível de uma turbina a gás (tipo turbofan) utilizada no campo da aeronáutica. Para a execução desse trabalho utilizou-se de pesquisas bibliográficas acerca do ciclo termodinâmico, tipos de turbinas aeronáuticas, empuxo, consumo específico e os componentes de uma turbofan. A partir dos resultados, obtidos pela modelagem da turbofan no software GSP (Gas Turbine Simulation Program), observou-se que o empuxo e o consumo específico de combustível variam com as condições propostas no trabalho, que envolvem a variação do número de Mach, altitude, vazão mássica de combustível e razão de by-pass. Ao final, sugere-se como trabalhos futuros, a variação de mais parâmetros de entrada, tais como, a razão de compressão do compressor e a inserção de um controle de arrefecimento da turbina pelo ar retirado do compressor. Palavras-chave: Turbina aeronáutica, turbofan, desempenho, empuxo, consumo específico, software GSP, Rolls-Royce BR710.

Revisiting RFID Mifare Classic security in the context of investigations that account millionaire losses a case study based on the ticketing system implemented in Brazil/ Revisitando a segurança do RFID Mifare Classic no contexto de investigações que contabilizam perdas milionárias um estudo de caso baseado no sistema de bilhética implementado no Brasil

Electronic systems in the infrastructure of public and private transport services are increasing. This growth comes from the various benefits for its implementation. In the capital of Brazil, the Federal District, as well as other federative entities, an electronic ticketing system based on smart cards was adopted. The card adopted in the capital belongs to the Mifare Classic series whose internal characteristics are widely known. Although several vulnerabilities are known, this card is still widely used in Brazil and worldwide. The focus of this study is on the security of this card as a credit storage medium within the ticketing system adopted locally. The most relevant and known vulnerabilities were enumerated. These vulnerabilities were confronted with the real possibility of building a cloned card. As an expected result, it was possible to build a cloned and accepted card within the system. Finally, significant storage areas were revealed: serial number location, registration number, credit total, credit batches and a 64 bits signature. This reinforces the need to withdraw Mifare Classic cards urgently

Tecido acrobático a partir de um projeto de extensão: reflexão na educação física

The search for circus activity classes, especially acrobatic tissue, is constantly increasing in contemporary times, with a great demand in projects that are associated with these arts. This study aimed to show how the extension project “Tecendo a Corporeidade” (Weaving the Corporeity) was created in the Physical Education Degree course at the Regional University of Cariri (Iguatu-CE). The project has 25 participants and the sample was composed by two teachers, one being the creator of the project and the other the scholarship student. Thus, it is a qualitative research, in which a structured questionnaire was used as a data collection instrument composed of 15 questions about the emergence and functionality of the extension project. According to the responses, it is concluded that the emergence of the project occurred through the experience of the responsible teacher, who had previously had contact with the practice of gymnastics when teaching.A busca por aulas de atividades circenses, em especial o tecido acrobático, está em uma constante crescente na contemporaneidade, existindo uma grande demanda em projetos que estejam associados a essas artes. Esse estudo teve como objetivo apresentar de que forma surgiu o projeto de extensão “Tecendo a Corporeidade” no curso de Licenciatura em Educação Física da Universidade Regional do Cariri (Iguatu-CE). O projeto possui 25 participantes e a amostra foi composta por duas professoras, uma idealizadora do projeto e a professora bolsista. Dessa forma, trata-se de uma pesquisa qualitativa, na qual utilizou-se como instrumento de coletas de dados um questionário estruturado composto por 15 perguntas acerca do surgimento e funcionalidade do projeto de extensão. De acordo com as respostas das participantes, concluiu-se que o surgimento do projeto se deu através da experiência da professora responsável, que previamente havia tido contato com a prática ao ministrar o conteúdo de ginástica

Species composition and richness of anurans in Cerrado urban forests from central Brazil

Brazil harbors the greatest diversity of amphibians on the planet although there are few studies dealing with urban fauna. The objective of this study is to describe the species composition and richness of anurans in urban Cerrado fragments from Campo Grande municipality, Mato Grosso do Sul state, central Brazil. The specimens were sampled in three stages through pitfall traps and visual/acoustic surveys. Seventeen species were recorded (17.7% of anuran species registered in Mato Grosso do Sul), with Leptodactylidae and Hylidae being the most represented families. The existence of a high number of green areas and water bodies in the urban area likely favors anuran species in the region. The anuran communities in urban areas of Campo Grande were dominated by species which use a broad range of habitats. In this study there was the record of a new species of anuran, Proceratophrys dibernardoi, for the state of Mato Grosso do Sul. The forest fragments that had the highest similarity for species composition were those with similar environmental conditions. The knowledge of the fauna that occurs in urban areas is important because natural habitats suffer severe fragmentation and degradation and species present in these areas may disappear in a shorter period of time

Application of controlled-release nitrogen fertilizer in irrigated common bean crops

The use of adequate management practices and high nitrogen fertilizer rates have contributed to increase the common bean grain yield, however, the application of nitrogen fertilizer at sowing still requires evaluations for irrigated crops in the Brazilian Cerrado biome region. Thus, the objective of this work was to evaluate the effect of application of different rates of controlled-release nitrogen fertilizer—dimethylpyrazole phosphate (DMPP)—at sowing and as top-dressing on agronomic performance and leaf area index of irrigated common bean crops grown in the Brazilian Cerrado biome region. A randomized block design in a 4×3 factorial arrangement with four replications was used. The treatments consisted of four nitrogen rates (0, 60, 120, and 180 kg ha-1) and three application forms (100% at sowing, 100% as top-dressing, and 50% at sowing + 50% as top-dressing). Irrigation was managed with class A tanks and two-day intervals. The nitrogen applied at the different stages of the crop did not affect the production components of the common bean plants. The highest grain yields were found with the nitrogen rates of 180 kg ha-1 in 2015 (1,756.37 kg ha-1), and 123.98 kg ha-1 in 2016 (1,799.63 kg ha-1).The use of adequate management practices and high nitrogen fertilizer rates have contributed to increase the common bean grain yield, however, the application of nitrogen fertilizer at sowing still requires evaluations for irrigated crops in the Brazilian Cerrado biome region. Thus, the objective of this work was to evaluate the effect of application of different rates of controlled-release nitrogen fertilizer—dimethylpyrazole phosphate (DMPP)—at sowing and as top-dressing on agronomic performance and leaf area index of irrigated common bean crops grown in the Brazilian Cerrado biome region. A randomized block design in a 4×3 factorial arrangement with four replications was used. The treatments consisted of four nitrogen rates (0, 60, 120, and 180 kg ha-1) and three application forms (100% at sowing, 100% as top-dressing, and 50% at sowing + 50% as top-dressing). Irrigation was managed with class A tanks and two-day intervals. The nitrogen applied at the different stages of the crop did not affect the production components of the common bean plants. The highest grain yields were found with the nitrogen rates of 180 kg ha-1 in 2015 (1,756.37 kg ha-1), and 123.98 kg ha-1 in 2016 (1,799.63 kg ha-1)

A Influência da Racionalidade Limitada na Institucionalização das Alterações Orçamentárias

The research aims to seek information on how the influence of limited rationality occurs in the institutionalization of budgetary changes. It aims to analyze how the bounded rationality, proposed by Bogt e Scapens (2018), ends up influencing managers in decision making and budget choices. The study is justified by the contribution that concerns the feeling about limited rationality and its influence on budgetary changes, making it possible to understand the relationship between the two. This is a unique, descriptive case study with a qualitative approach. A semi-structured interview and structured questionnaires were carried out, these in turn were analyzed by the method of discourse analysis, and the research was carried out in an industry located in the West of the State of Paraná, founded in 2006, and since then it has been standing out in the scenario national. as an important wheat miller. The main results demonstrate that Limited Rationality is seen as a natural process and divergence of thoughts and ideas is expected among the participants in the elaboration of budget changes, that the rule element and routines are directly interconnected within the budget process, as well as the elements , actions and institutionalization.A pesquisa tem como objetivo buscar informações de como ocorre a influência da racionalidade limitada na institucionalização das alterações orçamentárias. Visa analisar como a racionalidade limitada, proposta por Bogt e Scapens (2018), acaba influenciando os gestores na tomada de decisão e nas escolhas orçamentárias.  O estudo se justifica pela contribuição que concerne o sentimento sobre a racionalidade limitada e sua influência nas alterações orçamentárias, possibilitando compreender a relação entre os dois. Trata-se de um estudo de caso único, descritivo e tem abordagem qualitativa. Foram realizados uma entrevista semiestruturada e questionários estruturados, estes por sua vez foram analisados pelo método de análise do discurso, sendo a pesquisa realizada em uma indústria situada no Oeste do Estado do Paraná, sendo fundada em 2006, e desde então vem se destacando no cenário nacional como importante beneficiadora de trigo. Os principais resultados demonstram que a Racionalidade Limitada é vista como um processo natural e é esperada a divergência de pensamentos e ideias entre os participantes da elaboração das alterações orçamentárias, que o elemento regra e rotinas estão diretamente interligados dentro do processo orçamentário, assim como os elementos, ações e institucionalização

Rede Social e Papéis de Gênero de Casais Ribeirinhos de uma Comunidade Amazônica

This study describes the social network of two couples from a bordering community (Araraiana River, Municipality Ponta de Pedras, Marajó Island/Pará). Data were collected through a socio demographic inventory, a routine inventory and a field diary and analyzed by a network map. It was observed that the relation of the couples is based on economic and work alliances, company for leisure or religious activity. It has also been found that these relationships are marked by gender patterns which delimit the environments of daily activities, define the status that each one holds in the family and condition the formation of bonds in social networks.Este estudo descreve as redes sociais de dois casais de uma comunidade ribeirinha (Rio Araraiana, Município de Ponta de Pedras, Ilha do Marajó/Pará). Os dados foram coletados com um inventário sócio-demográfico, um inventário de rotina e diários de campo e, analisados pelo mapa de rede de Sluzki. Constatou-se que os vínculos dos casais são baseados em alianças de ajuda econômica e de trabalho, companhia para lazer ou atividade religiosa. Verificou-se que as relações são marcadas por padrões de gênero que delimitam os ambientes das atividades cotidianas, definem o status ocupado na família e condicionam a formação de vínculos na rede social. &nbsp