Estudo analítico, numérico e experimental dos parâmetros do processo filament winding em superfícies de revolução

O processo de Filament Winding (que consiste em enrolar fibras sobre um mandril), na grande maioria das vezes, forma estruturas de paredes finas e delgadas que são adequadas para uma análise estrutural pela teoria das cascas e membranas, sob as hipóteses de Kirchhoff-|Love, em um estado plano de tensões. A tubeira, cuja fabricação é o objeto que motivou este estudo, tem uma superfície definida por uma equação de terceiro grau e está submetida à pressão interna. Sendo uma superfície não trivial, é adequada para uma aplicação analítica dos fundamentos teóricos mencionados, com alguma simplificação, já que é uma superfície de revolução. Assim, a superfície é definida pelos coeficientes fundamentais de primeira e segunda ordem com determinação das curvaturas e dos raios de curvatura. As tensões e forças por unidade de comprimento (obtidas com os coeficientes fundamentais) são utilizadas para dimensionar o laminado pela Análise em Rede e pela Teoria Clássica de Laminados, de acordo com o ângulo de enrolamento. A Análise em Rede, normalmente considerada uma teoria simplificada que superdimensiona o laminado, não se confirma, neste trabalho, como um procedimento adequado, pois o componente ficaria subdimensionado se comparado à Teoria Clássica dos Laminados, avaliada com um critério de falha. Porém, o processo Filament Winding (FW) tem nas características geométricas da superfície uma limitação natural para executar a trajetória da fita obtida analiticamente com a análise estrutural, que é o escorregamento da fita sobre a superfície durante o enrolamento. Assim, em função do coeficiente de escorregamento, que deve ser menor ou igual ao coeficiente de atrito, são obtidas as trajetórias possíveis e, em função destas, calculados os ângulos de escorregamento permitidos pelo processo. Além disso, o FW tem uma característica particular devido à utilização de fibras contínuas: como o enrolamento não é interrompido nas extremidades do componente há um procedimento de retorno das fibras que depende de uma equação diofantina, que gera o entrelaçamento (pattern) das fibras. Além de respeitar uma relação específica de números inteiros, o procedimento de retorno depende também do coeficiente de atrito, cujos efeitos foram também analisados neste estudo e um procedimento alternativo apresentado. As equações diferenciais (EDOs) sem solução analítica foram resolvidas pelos processos numéricos de Runge Kutta e de Euler, utilizando o software MAPLE.Filament winding by wrapping thin tows over a mandrel, creates shells that are suitable for structural analysis by the shell and membrane theory under the Kirchhoff-Love hypothesis. The nozzle, whose manufacturing motivated this study, has a surface defined by a third degree equation and is subjected to internal pressure. As a nontrivial surface, serves as a good example to apply the complete theory to manufacture with Filament Winding. So, with determination of the first and second order fundamental coefficients, curvatures and radii of curvatures of the surface are obtained. With them, tensions and forces per unit length are calculated to dimension the laminate by Netting Analysis and Classical Laminate Theory, in function of the winding angle. Netting Analysis, usually considered a simplified theory that oversizes the laminate, is not confirmed in this paper as an appropriate procedure, since the component would be undersized compared to the Classical Laminate Theory evaluated with a failure criterion. FW has in the geometrical characteristics of the surface a natural limitation for executing the tow trajectory obtained analytically with structural analysis, which is the slippage of the tow over the surface during winding. Thus, as a function of the slippage coefficient, which must be less than or equal to the friction coefficient, the possible trajectories are obtained and, as a function of these, the winding angles allowed by the process are calculated. In addition, FW has a particular feature due to the use of continuous fibers. Since the winding is not interrupted at the ends of the component, there is a tow returning procedure that depends on a diophantine equation that generates the pattern of the filaments. Besides respecting a specific integer relation, the return procedure also depends on the slippage coefficient, whose effects were also analyzed in this study and an alternative procedure presented. The differential equations (ODEs) without analytical solution were solved by the Runge Kutta method with MAPLE software

Bases para um programa de treinamento orientada para a formação de empreendedores, através do desenvolvimento de competências, centrada nas atividades do indivíduo frente a organização

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.O presente trabalho aborda um estudo sobre as atividades e competências que o empreendedor que atua na administração de empreendimentos de base tecnológica mobiliza diante de situações profissionais. Analisa, o papel da academia como formadora do indivíduo e procura delinear até que ponto os conhecimentos lá construídos e adquiridos contribuem com a atividade profissional do empreendedor onde as forças produtivas, econômicas, sociais e políticas verdadeiramente se articulam, exigindo desse ator, invariavelmente, respostas rápidas e bem estruturadas, viabilizando a sobrevivência da empresa e do próprio empreendedor. Considera a utilização de conteúdos e metodologia de aprendizagem já implementados para ampliar as competências do empreendedor e aumentar as chances de sucesso desse ator frente às conturbadas situações impostas pela articulação das forças do mercado. Além da pesquisa bibliográfica, o foco deste trabalho teve como referência, de um lado, os empreendedores que dirigem empresas de base tecnológica seja em regime de pré-incubação ou fora dela, e de outro, acadêmicos dos cursos de Ciências da Computação e Sistemas de Informação que pretendem ingressar no mercado de trabalho como donos do próprio negócio

Tfg (Trk fused gene) is a Carma-1/IKKgamma interacting protein involved in CD40-induced canonical NF-KB signaling

Carma-1 is required for B cell receptor-/CD40- and T cell receptor-/CD28-induced B- and T-cell activation via JNK and NF-betaB. In B cells, Carma-1 becomes phosphorylated by PKCbeta, leading to its oligomerization. Subsequent Bcl10 binding induces IKKbeta-activation and, thereby, canonical NF-KB signalling. Despite these findings it is still unknown how exactly Carma-1 is connected to the plasma membrane and to the IKK-complex. Therefore, we purified Carma-1 complexes from mouse CH12 B cells using anti-Carma-1 affinity columns. Mass spectrometric analyses of the column eluates demonstrated the presence of Carma-1 as well as three previously uncharacterized adaptor proteins in B cells, one of which was the Trk-fused gene (Tfg), an adaptor protein containing PB1 and coiledcoil domains. Whereas Tfg was originally identified as fusion partner of oncogenic Trk tyrosine kinase mutants, the normal cellular homologue of Tfg has so far not been described in B cells. However, Tfg has been shown in other systems to interact with IKKgamma and to enhance TNFinduced NF-KB activation. Tfg and Carma-1 co-localized at the plasma membrane and perinuclear structures in B cells. We further corroborated the interactions of Tfg, IKKgamma and Carma-1 by Blue Native gel electrophoresis, where Carma-1 and Tfg formed a 0.7–1 MDa complex. Ectopic expression of Tfg increased the molecular mass of IKKgamma complexes, fused IKKgamma, Bcl10 and Carma-1 complexes to a ~2 MDa complex, and increased basal and CD40-induced canonical activity of NF-KB and IKKbeta. In contrast, shRNA-mediated silencing of Tfg decreased CD40-induced IKKbeta activity. Very interestingly, in primary B cells, highest expression of Tfg was detected in marginal zone and B1 B cells, and Carma-1 and Tfg formed complexes in these B cells. Since Carma-1 is required for marginal zone B cell and B1 B cell development, we suggest that a functional interaction between Carma-1 and Tfg contributes to development and maintenance of these cells by means of canonical NF-KB signals

PREDIÇÃO DO DESEMPENHO ACADÊMICO FINAL PELA PERFORMANCE NO PRIMEIRO ANO DO ENSINO SUPERIOR: UM ESTUDO DE CASO NO CURSO DE GRADUAÇÃO EM ADMINISTRAÇÃO DE UMA UNIVERSIDADE FEDERAL

O presente estudo procura verificar a validade preditiva do desempenho acadêmico de um estudante ao final do primeiro ano do ensino superior para a tendência de seu desempenho ao longo de todo o ensino superior, até a conclusão. A intenção de estudo que se coaduna com tal objetivo surge da preocupação com a criação de indicadores que permitam um diagnóstico antecipado dos casos de estudantes que tenham tendência a baixo desempenho, permitindo assim, atuação tempestiva da gestão universitária no sentido de intervir com ações de gestão acadêmica ativa para tratar dos casos antes que se consolidem ou agravem. Para a realização da análise foi feito estudo de caso incidente sobre os dados dos ingressantes no Curso de Graduação em Administração de uma Universidade Federal no ano de 2009. Selecionados os sujeitos, realizaram-se operações de correlação entre o desempenho no primeiro ano e na conclusão do curso para verificar se aquele fator prediz este. O estudo, quali-quantitativo, com ênfase na segunda componente do título metodológico, identificou que existe relevante correlação entre as variáveis, apontando que – ao menos para o caso em tela – o desempenho no primeiro ano seria suficiente para indicar a tendência de desempenho globa

Evaluating the networking performance of Linux-based home router platforms for multimedia services

ABSTRACT Wireless router platforms based on the Linux operating system are becoming popular in consumers' home networks. The transmission of multimedia data or their use as mediaaware network elements imposes high traffic and computational loads on these devices. Thus, it is interesting to evaluate the networking and processing capabilities of such home router platforms in order to assess their usefulness for improved multimedia services such as in-network H.264/SVC video stream adaptation. This paper presents a performance evaluation of three home router platforms representative for low-end, mid-range, and high-end devices. The scope of the evaluation is the performance of the Linux networking stack on these routers; results for both application-layer (TCP and UDP) transmission and kernel-level (UDP) traffic routing are given. The results show that both TCP and UDP throughputs are significantly below (less than half of) the outgoing (wired) links' nominal capacities and depend very much on the sizes of the transmitted data blocks. This clearly indicates that the networking performance is limited by the platforms' processing capabilities and the lack of mechanisms that offload networking tasks from the CPUs. This behaviour cannot be observed on today's PC systems and has to be considered when deploying multimedia services on these network devices. Furthermore, a detailed analysis of the Linux networking stack reveals that the performance is heavily impacted by the netfilter code, even when no packet filtering or network address translation is being performed. Considerable performance gains can be achieved when this netfilter code is bypassed

Magnetic resonance imaging features of craniofacial fibrous dysplasia

Purpose: To assess the value of magnetic resonance imaging (MRI) in detecting craniofacial fibrous dysplasia (CFD) and diagnosing and differentiating it from intraosseous meningioma. Additionally, the MRI appearance of the typical computed tomography (CT) imaging feature, the ground glass phenomenon, was evaluated. Material and methods: MRI datasets of 32 patients with CFD were analysed retrospectively. Detectability in MRI was assessed by analysis of 10 randomly selected patients with CFD and 10 normal controls by two blinded readers. Changes of affected bone, internal lesion structure, T1 and T2 signal intensity, and contrast enhancement of the lesion in general and ground glass areas in particular were assessed. Ten patients with intraosseous meningioma (one in each) served as differential diagnosis for CFD. Results: All 10 CFD lesions were reliably detected in MRI. In 32 patients 36 CFD lesions were evaluated. In 66.7% CFD were iso- to hypointense in T1 and hyperintense in T2; this proportion was similar for ground glass areas (65.7%). Ground glass areas were more homogeneously structured than the whole CFD lesion in both T1 (100% vs. 56%, respectively) and T2 (91% vs. 61%, respectively). Contrast enhancement was found in 97% of complete CFD lesions and 93% of ground glass areas. The accuracy for CFD vs. intraosseous meningioma was 100% for 'no soft-tissue component' and 98% for ‘bone broadening' in MRI. Conclusions: Distinct morphological changes of CFD are reliably detected in MRI and allow differentiation from intraosseous meningioma. Areas with ground glass phenomenon in CT show a predominantly homogenous internal structure in MRI with contrast enhancement

Characterization of a CdZnTe detector for a low-power CubeSat application

We report spectral and imaging performance of a pixelated CdZnTe detector custom designed for the MeVCube project: a small Compton telescope on a CubeSat platform. MeVCube is expected to cover the energy range between 200 keV and 4 MeV, with a sensitivity comparable to the one of the last generation of larger satellites. In order to achieve this goal, an energy resolution of few percent in full width at half maximum (FWHM) and a 3-D spatial resolution of few millimeters for the individual detectors are needed. The severe power constraints present in small satellites require very low power read-out electronics for the detector. Our read-out is based on the VATA450.3 ASIC developed by Ideas, with a power consumption of only 0.25 mW/channel, which exhibits good performance in terms of dynamic range, noise and linearity. A 2.0 cm× 2.0 cm× 1.5 cm CdZnTe detector, with a custom 8 × 8 pixel anode structure read-out by a VATA450.3 ASIC, has been tested. A preliminary read-out system for the cathode, based on a discrete Amptek A250F charge sensitive pre-amplifier and a DRS4 ASIC, has been implemented. An energy resolution around 3% FWHM has been measured at a gamma energy of 662 keV; at 200 keV the average energy resolution is 6.5%, decreasing to ≲ 2% at energies above 1 MeV. A 3-D spatial resolution of ≈ 2 mm is achieved in each dimension.Peer Reviewe