A Hybrid Reduced-Order Model for the Aeroelastic Analysis of Flexible Subsonic Wings—A Parametric Assessment

A hybrid reduced-order model for the aeroelastic analysis of flexible subsonic wings with arbitrary planform is presented within a generalised quasi-analytical formulation, where a slender beam is considered as the linear structural dynamics model. A modified strip theory is proposed for modelling the unsteady aerodynamics of the wing in incompressible flow, where thin aerofoil theory is corrected by a higher-fidelity model in order to account for three-dimensional effects on both distribution and deficiency of the sectional air load. Given a unit angle of attack, approximate expressions for the lift decay and build-up are then adopted within a linear framework, where the two effects are separately calculated and later combined. Finally, a modal approach is employed to write the generalised equations of motion in state-space form. Numerical results were obtained and critically discussed for the aeroelastic stability analysis of a uniform rectangular wing, with respect to the relevant aerodynamic and structural parameters. The proposed hybrid model provides sound theoretical insights and is well suited as an efficient parametric reduced-order aeroelastic tool for the preliminary multidisciplinary design and optimisation of flexible wings in the subsonic regime

Intelligent state observers : proposals

Orientador: Celso Pascoli BotturaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: O problema de se observar o estado do sistema nasce da necessidade de se controlar plantas cujo estado não se pode medir. Convencionalmente são utilizados observadores baseados em modelos dinâmicos para resolver esse problema, através da construção de estimativas do estado desconhecido. Nesta tese, é abordada uma solução alternativa para este problema. Várias propostas de observadores inteligentes, são realizadas com base em mapeamentos entre subespaços gerados pelas equações que regem a dinâmica não linear do sistema, utilizando várias técnicas de inteligência computacional, capazes de apresentar estimativas do estado do sistema dinâmico através de observadores que não apresentam um comportamento dinâmico com relação ao tempo.Abstract: The state observer problem arises from the necessity of controlling plants whose state can not be measured. Usually dynamic model based observers are used to solve this problem, for estimating unknown state. In this thesis an alternative solution for this problem is presented. Various proposals for intelligent observers are made based on mappings between subspaces generated by the equations describing the nonlinear dynamics of the system, using various computational intelligence techniques able to present state estimates for the dynamic system through nonlinear observers that do not exhibit a dynamic behavior with respect to time.MestradoAutomaçãoMestre em Engenharia Elétric

Extension of analytical indicial aerodynamics to generic trapezoidal wings in subsonic flow

Analytical indicial aerodynamic functions are calculated for several trapezoidal wings in subsonic flow, with a Mach number 0.3≤ Ma≤ 0.7. The formulation herein proposed extends well-known aerodynamic theories, which are limited to thin aerofoils in incompressible flow, to generic trapezoidal wing planforms. Firstly, a thorough study is executed to assess the accuracy and limitation of analytical predictions, using unsteady results from two state-of-the-art computational fluid dynamics solvers as cross-validated benchmarks. Indicial functions are calculated for a step change in the angle of attack and for a sharp-edge gust, each for four wing configurations and three Mach numbers. Then, analytical and computational indicial responses are used to predict dynamic derivatives and the maximum lift coefficient following an encounter with a one-minus-cosine gust. It is found that the analytical results are in excellent agreement with the computational results for all test cases. In particular, the deviation of the analytical results from the computational results is within the scatter or uncertainty in the data arising from using two computational fluid dynamics solvers. This indicates the usefulness of the developed analytical theories

GESTÃO DE CUSTOS E ENERGIA: EVIDÊNCIAS, OPORTUNIDADES E RESULTADOS OBTIDOS EM UM CASO CONCRETO

The acquisition of electricity in the Free Contracting Environment - FCE - is a consolidated alternative of cost reduction, since it allows the previous contracting of the energy to be consumed at a freely negotiated price among market players. The objective of this study was to demonstrate, through a case study, how the acquisition of electric energy in the FCE can help reduce organizational costs and generate significant economic results. Methodologically, it was an explanatory research, with quanti-qualitative approach, whose instruments of data collection were the bibliographical research and documentary analysis coming from a case study. The analysis of the data occurred through electronic spreadsheets, graphics, and, finally, content and comparative analysis. The results demonstrate the cost reduction, of the R$5,000,000.00 (five million “reais”), a lower payback in less than two months, and also an Internal Rate of Return - IRR - of 365$ 5.000,000,00 (cinco milhões de reais), payback inferior a dois meses e uma Taxa Interna de Retorno – TIR de 365%

Contribution of complement activation pathways to neuropathology differs among mouse models of Alzheimer's disease

<p>Abstract</p> <p>Background</p> <p>Complement proteins and activation products have been found associated with neuropathology in Alzheimer's disease (AD). Recently, a C5a receptor antagonist was shown to suppress neuropathology in two murine models of AD, Tg2576 and 3xTg. Previously, a genetic deficiency of C1q in the Tg2576 mouse model showed an accumulation of fibrillar plaques similar to the complement sufficient Tg2576, but reactive glia were significantly decreased and neuronal integrity was improved suggesting detrimental consequences for complement activation in AD. The goal of this study was to define the role of the classical complement activation pathway in the progression of pathology in the 3xTg mouse that develops tangles in addition to fibrillar plaques (more closely reflecting human AD pathology) and to assess the influence of complement in a model of AD with a higher level of complement hemolytic activity.</p> <p>Methods</p> <p>3xTg mice deficient in C1q (3xTgQ-/-) were generated, and both 3xTg and 3xTgQ-/- were backcrossed to the BUB mouse strain which has higher in vitro hemolytic complement activity. Mice were aged and perfused, and brain sections stained for pathological markers or analyzed for proinflammatory marker expression.</p> <p>Results</p> <p>3xTgQ-/- mice showed similar amounts of fibrillar amyloid, reactive glia and hyperphosphorylated tau as the C1q-sufficient 3xTg at the ages analyzed. However, 3xTg and 3xTgQ-/- on the BUB background developed pathology earlier than on the original 3xTg background, although the presence of C1q had no effect on neuropathological and pro-inflammatory markers. In contrast to that seen in other transgenic models of AD, C1q, C4 and C3 immunoreactivity was undetectable on the plaques of 3xTg in any background, although C3 was associated with reactive astrocytes surrounding the plaques. Importantly, properdin a component of the alternative complement pathway was associated with plaques in all models.</p> <p>Conclusions</p> <p>In contrast to previously investigated transgenic models of AD, development of neuropathology in 3xTg mice, which progresses much slower than other murine models, may not be influenced by fibrillar amyloid mediated activation of the classical complement pathway, suggesting that the alternative complement pathway activation or a C3-independent cleavage of C5 could account for the detrimental effects in these mice that are prevented by the C5a receptor antagonist. Furthermore, the paucity of complement activation may be a factor in the slower kinetics of progression of pathology in the 3xTg model of this disease.</p

ALGORITMOS GENÉTICOS APLICADOS NA CRIAÇÃO DE AGENDAS DE HORÁRIO SEMANAL DE AULAS

Determining a weekly class schedule is a computationally complex problem whose computational cost can increase exponentially in relation to the number of variables involved in the solution. There are several software on the market that build this timetable based on deterministic rules. Alternatively, we intend to build this solution using Genetic Algorithms, making use of its exploratory capacity in multidimensional spaces.A determinação de uma agenda semanal de aulas é um problema computacionalmente complexo, cujo custo computacional pode aumentar exponencialmente em relação ao número de variáveis envolvidas na solução. Existem no mercado diversos software que constroem essa agenda com base em regras determinísticas. Alternativamente, pretende-se construir essa solução utilizando Algoritmos Genéticos, fazendo uso de sua capacidade exploratória em espaços multidimensionais

Synthesis and properties of new paramagnetic hybrid bayerite from Al(0)/naphthalene dianhydride reaction

The reaction of Naphthalene 1,4,5,8-dianhydride (NTCDA) with elemental aluminum(0) powder is studied in an aqueous alcoholic KOH mixture to search for the NTCDA anion and dianion electron-adducts. After analyzing various reaction conditions it was found that the reaction yielded a greenish precipitate in 3:1 (v:v) ethanol:water mixture. This powder is composed mainly of aluminum trihydroxide crystallites of bayerite [&#945;-Al(OH3)(s)] and the organic content is approximately 6%. This hybrid material proved to be paramagnetic even after exposure to air for one year and at temperatures up to 200 ºC. Typical carbonylic bound to metal IR bands and reflectance UV-VIS spectra demonstrate the entrapment of NTCDA radical anion into the aluminum trihydroxide, hence rendering its green color and a paramagnetic behavior. Thus, besides the understanding of an aluminum reaction in suspension, the entrapment of an organic material (NTCDA) that stays stable as the corresponding radical can provide an interesting option for the synthesis of aluminum trihydroxide composites.FAPESPCNPQCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

CONVERSOR AC-DC EM MODO CONTÍNUO DE CORRENTE COM COMPENSAÇÃO EM FREQUÊNCIA PARA LÂMPADAS LED DE BAIXO CUSTO E ALTA EFICIÊNCIA

Este artigo apresenta uma nova arquitetura de um driver de LEDs de alto brilho, com baixo custo e elevado rendimento. Emprega-se um conversor do tipo CUK em modo contínuo de corrente com compensação em frequência, para alimentação dos LEDs de alto brilho através da rede elétrica, a partir de 85V a 265V, operando em alta frequência com comutação por Modulação por Largura de Pulso (MLP) e conectado a um filtro ressonante LC série para alimentação da carga com proteção contra surto de tensão na entrada. Foram utilizados vinte LEDs de Alta Potência da OSRAM 720-GWPSL e um circuito com corrente constante em modo Off-line. A arquitetura proposta visa apresentar uma proposta de um driver de baixo custo e baixo consumo de corrente. É apresentado o estudo comparativo entre o protótipo deste dispositivo a partir dos gráficos obtidos com os resultados de medições em laboratório

Aeroelastic model and analysis of an active camber morphing wing

Morphing aircraft structures usually introduce greater compliance into aerodynamic sections, and therefore will affect the aeroelasticity with the potential risk of increased flutter. A low-fidelity model of an active camber morphing wing and its aeroelastic model are developed in order to investigate the potential critical speed by exploiting its chord-wise dimension and flexibility. Such a model may be used for conceptual design, where low fidelity models are used to explore and optimise a wide range of configurations. The morphing camber concept is implemented using a continuous representation of a two-segment structure with a rigid segment and a deformable part. The aeroelastic model is developed based on both steady and unsteady aerodynamic models, so that different parameters can be easily modified to examine changes in the flutter solutions. Of particular interest are the ratio of the morphing segment length to the chord, and its relative stiffness, as such morphing camber is potential operated using the deformable part as a flap. By comparing the results of the quasi-steady and unsteady aerodynamic models, it is shown that the quasi-steady aerodynamic model gives a more conservative prediction of the flutter speed. In addition, responses in phase space are simulated to show the fundamental aeroelastic behaviour of the morphing camber wing. It is also shown that the active compliant segment can be used to stabilise the morphing aircraft by using feedback control. This paper provides a system-level insight through mathematical modelling, parameter analysis and feedback control into dynamics applications of morphing camber