696 research outputs found

    Caracterização de incertezas em modelos estruturais dinâmicos de painéis honeycomb Al-Al

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    Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Faculdade UnB Gama, 2017.No Trabalho de Conclusão de Curso 1, foi apresentado um estudo exploratório no impacto de incertezas associadas às dimensões de uma viga engastada de aço no cálculo das frequências naturais e, no presente trabalho, seu uso foi apliado para um caso mais complexo: um painel sanduíche. O atual escopo consiste no Satélite Geoestacionário de Defesa e Comunicações Estratégicas (SGDC), um programa do Governo Brasileiro lançado com o objetivo de prover cobertura de serviços de Internet aos brasileiros e estabelecer soberania nas comunicações estratégicas do governo brasileiro. Espera-se que o SGDC 2 entre em operação até 2022 e, para auxiliar na prevenção de possíveis problemas relacionados à sua operação, desde o lançamento até o fim da sua vida útil, é importante a construção de um modelo computacional capaz de auxiliar na previsão dos modos de vibração dos painéis sanduíches do tipo honeycomb de modo que seja possível caracterizar as incertezas associadas ao modelo e às dimensões dos painéis. O presente trabalho apresenta uma análise numérica e experimental nos modos naturais de vibração do painel sanduíche que será utilizado no SGDC 2, cuja metodologia se fundamenta no uso do Método de Monte Carlo. Ao final do trabalho, percebe-se que a incerteza de método é maior que a incerteza de parâmetros de entrada.In the Graduation Thesis 1 was presented an exploratory study on impact of uncertainties associated with the dimensions of a steel cantilever in natural frequencies and, in this present work, your use has been expanded to a more complex case: a sandwich panel. The current scope consists of the Geostationary Satellite of Defense and Strategic Communications (SGDC), a Brazilian Government program launched with the objective to provide a coverage of Internet service to Brazilians and establish sovereignty in strategic communications from the Brazilian Government. Is expected to launch the SGDC-2 until 2022 and, to assist in the prevention of possible problems related to your operation, since the launch to the end of your life, it is important the construction of a computational model capable to assist in the prediction of vibration modes of the honeycomb sandwich panels so that it is possible to characterize the uncertainties associated with the model and the dimensions of the panels. This paper presents a numerical and experimental analysis on natural modes of vibration of sandwich panel that will be used in the SGDC 2, whose methodology is based on the use of the Monte Carlo method. At the end of this work, is noted that the method uncertainty is greater than the input parameter uncertainty

    Effects of laser-textured on rake face in turning PCD tools for Ti6Al4V

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    The demand inherent to the aeronautical industry in terms of productivity and quality requirements leads to develop new cutting tools. Hence, PCD tools meet the requirements in productivity while machining low machinability aeronautical alloys such as Ti6Al4V. Tool chipbreakers play a considerable role in terms of tool life. However, due to the extreme conditions (temperature and pressure) required to manufacture PCD tools, any complex geometry on tool rake faces is not viable, so chipbreakers are not possible, except for those external to inserts. This work proposes a groove-type laser engraved chipbreaker design and a manufacturing methodology, with experimental validation on turning a Ti6Al4V workpiece. The so-manufactured chipbreakers achieve titanium alloy chip fragmentation, making easy chip removal from the cutting zone. A set of experiments involving various laser parameters to characterize the PCD depth and surface integrity and experimental validation for those chipbreakers designs were carried out in finishing cutting conditions. The optimum parameters for the engraving of PCD were found, obtaining satisfactory breakage of titanium chips. Chip length was always below 17.29 mm.Authors are grateful to Basque government group IT IT1337- 19, the Ministry of Mineco REF DPI2016-74845-R and PID2019- 109340RB-I00, and the UPV/EHU itself for the financial aid for the pre-doctoral grants PIF 19/96

    Topological confinement in an antisymmetric potential in bilayer graphene in the presence of a magnetic field

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    We investigate the effect of an external magnetic field on the carrier states that are localized at a potential kink and a kink-antikink in bilayer graphene. These chiral states are localized at the interface between two potential regions with opposite signs

    Hospital-acquired intestinal toxemia botulism in a newly diagnosed adult colon cancer patient

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    This manuscript reports a case of intestinal toxemia botulism in an adult with recently diagnosed metastatic colon cancer in whom botulism symptoms began 23 days after hospital admission. Representing the rarest form of botulism presentation in clinical practice, this infectious disease may have developed due to a cluster of predisposing factors that favored Clostridium botulinum colonization and the endogenous production of neurotoxins, among which are previous use of broad-spectrum antibiotics and colon changes related to the development of the neoplasia. This case highlights the importance of considering intestinal toxemia botulism in the differential diagnosis of a patient presenting with symmetrical descending flaccid paralysis, since immediate treatment with botulinum antitoxin may improve clinical outcomes

    Analysis of anti-Mullerian hormone (AMH) and its receptor (AMHR2) genes in patients with persistent Mullerian duct syndrome

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    Objective: To screen for mutations in AMH and AMHR2 genes in patients with persistent Mullerian duct syndrome (PMDS). Patients and method: Genomic DNA of eight patients with PMDS was obtained from peripheral blood leukocytes. Directed sequencing of the coding regions and the exon-intron boundaries of AMH and AMHR2 were performed. Results: The AMH mutations p.Arg95*, p.Arg123Trp, c.556-2A>G, and p. Arg502Leu were identified in five patients; and p.Gly323Ser and p.Arg407* in AMHR2 of two individuals. In silico analyses of the novel c.556-2A>G, p.Arg502Leu and p.Arg407* mutations predicted that they were harmful and were possible causes of the disease. Conclusion: A likely molecular etiology was found in the eight evaluated patients with PMDS. Four mutations in AMH and two in AMHR2 were identified. Three of them are novel mutations, c.556-2A>G, and p. Arg502Leu in AMH; and p.Gly323Ser in AMHR2. Arq Bras Endocrinol Metab. 2012;56(8):473-8Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [305743/2011-2, 314392/2009-2, 302084/2009-6]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (Fapesp) [06/50999-0]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP

    Pesquisa de mutações nos genes do hormônio antiMülleriano (AMH) e do seu receptor (AMHR2) em pacientes com síndrome de persistência dos ductos Müllerianos

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    OBJECTIVE: To screen for mutations in AMH and AMHR2 genes in patients with persistent Müllerian duct syndrome (PMDS). PATIENTS AND METHOD: Genomic DNA of eight patients with PMDS was obtained from peripheral blood leukocytes. Directed sequencing of the coding regions and the exon-intron boundaries of AMH and AMHR2 were performed. RESULTS: The AMH mutations p.Arg95*, p.Arg123Trp, c.556-2A>G, and p.Arg502Leu were identified in five patients; and p.Gly323Ser and p.Arg407* in AMHR2 of two individuals. In silico analyses of the novel c.556-2A>G, p.Arg502Leu and p.Arg407* mutations predicted that they were harmful and were possible causes of the disease. CONCLUSION: A likely molecular etiology was found in the eight evaluated patients with PMDS. Four mutations in AMH and two in AMHR2 were identified. Three of them are novel mutations, c.556-2A>G, and p.Arg502Leu in AMH; and p.Gly323Ser in AMHR2. Arq Bras Endocrinol Metab. 2012;56(8):473-8OBJETIVO: Analisar os genes AMH e AMHR2 em indivíduos com síndrome de persistência dos ductos de Müller (SPDM). PACIENTES E MÉTODO: Amostras de DNA genômico de oito pacientes com SPDM foram obtidas de leucócitos de sangue periférico. Sequenciamento direto da região codificadora e das áreas intrônicas próximas aos éxons dos genes AMH e AMHR foi realizado. RESULTADOS: As mutações p.Arg95*, p.Arg123Trp, c.556-2A>G e p.Arg502Leu no gene AMH foram identificadas em cinco pacientes e as mutações p.Gly323Ser e p.Arg407* no gene AMHR2, em dois indivíduos. As análises in silico das mutações c.556-2A>G, p.Arg502Leu e p.Arg407*, não descritas anteriormente na literatura, previram que elas são deletérias e possivelmente a causa da doença. CONCLUSÃO: Uma provável etiologia molecular foi encontrada nos oito pacientes portadores de SPDM avaliados. No gene do AMH foram identificadas quatro mutações e no AMHR2, duas mutações. Três das seis mutações encontradas são mutações novas, c.556-2A>G e p.Arg502Leu no gene AMH; e p.Gly323Ser no AMHR2. Arq Bras Endocrinol Metab. 2012;56(8):473-8473478Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    Suscetibilidade de operárias de Atta sexdens tratadas com o imunossupressor Sandimmun Neoral a Metarhizium anisopliae

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    The objective of this work was to evaluate if the immunosuppressant Sandimmun Neoral enhances the activity of Metarhizium anisopliae against the leaf-cutting ant Atta sexdens. The vulnerability to the pathogen was measured by comparing the mortality rate of worker ants subjected to the following treatments: immunosuppressant+control, immunosuppressant+M. anisopliae, excipient+control, excipient+M. anisopliae, control+M. anisopliae, and control. Worker ants treated with immunosuppressant+M. anisopliae showed the highest mortality rate in comparison with those subjected to all other treatments. The use of the immunosuppressant together with entomopathogenic fungus controlled leaf-cutting ants in laboratory conditions.O objetivo deste trabalho foi avaliar se o imunossupressor Sandimmun Neoral favorece a atividade de Metarhizium anisopliae contra a formiga cortadeira Atta sexdens. A vulnerabilidade ao patógeno foi medida ao se comparar a mortalidade de operárias expostas aos seguintes tratamentos: imunossupressor+controle, imunossupressor+M. anisopliae, excipiente+controle, excipiente+M. anisopliae, controle+M. anisopliae e controle. Operárias tratadas com imunossupressor+M. anisopliae apresentaram a maior taxa de mortalidade em comparação às submetidas a todos os outros tratamentos. O uso do imunossupressor juntamente com fungo entomopatogênico controlou as formigas cortadeiras em condições de laboratório

    Analysis of anti-Mullerian hormone (AMH) and its receptor (AMHR2) genes in patients with persistent Mullerian duct syndrome

    Get PDF
    Objective: To screen for mutations in AMH and AMHR2 genes in patients with persistent Mullerian duct syndrome (PMDS). Patients and method: Genomic DNA of eight patients with PMDS was obtained from peripheral blood leukocytes. Directed sequencing of the coding regions and the exon-intron boundaries of AMH and AMHR2 were performed. Results: The AMH mutations p.Arg95*, p.Arg123Trp, c.556-2A>G, and p. Arg502Leu were identified in five patients; and p.Gly323Ser and p.Arg407* in AMHR2 of two individuals. In silico analyses of the novel c.556-2A>G, p.Arg502Leu and p.Arg407* mutations predicted that they were harmful and were possible causes of the disease. Conclusion: A likely molecular etiology was found in the eight evaluated patients with PMDS. Four mutations in AMH and two in AMHR2 were identified. Three of them are novel mutations, c.556-2A>G, and p. Arg502Leu in AMH; and p.Gly323Ser in AMHR2. Arq Bras Endocrinol Metab. 2012;56(8):473-8Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [305743/2011-2, 314392/2009-2, 302084/2009-6]Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (Fapesp) [06/50999-0]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP
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