Optimization of vibrating structures to reduce radiated noise

In this work, we propose an approach for reducing radiated noise from `light' fluid-loaded structures, such as, for example, vibrating structures in air. In this approach, we optimize the structure so as to minimize the dynamic compliance (defined as the input power) of the structure. We show that minimizing the dynamic compliance results in substantial reductions in the radiated sound power from the structure. The main advantage of this approach is that the redesign to minimize the dynamic compliance moves the natural frequencies of the structure away from the driving frequency thereby reducing the vibration levels of the structure, which in turn results in a reduction in the radiated sound power as an indirect benefit. Thus, the need for an acoustic and the associated sensitivity analysis is completely bypassed (although, in this work, we do carry out an acoustic analysis to demonstrate the reduction in sound power levels), making the strategy efficient compared to existing strategies in the literature which try to minimize some measure of noise directly. We show the effectiveness of the proposed approach by means of several examples involving both topology and stiffener optimization, for vibrating beam, plate and shell-type structures.

Modeling Time-Varying Aggregate Interference in Cognitive Radio Systems, and Application to Primary Exclusive Zone Design

Accurately characterizing the time-varying interference caused to the primary users is essential in ensuring a successful deployment of cognitive radios (CR). We show that the aggregate interference at the primary receiver (PU-Rx) from multiple, randomly located cognitive users (CUs) is well modeled as a shifted lognormal random process, which is more accurate than the lognormal and the Gaussian process models considered in the literature, even for a relatively dense deployment of CUs. It also compares favorably with the asymptotically exact stable and symmetric truncated stable distribution models, except at high CU densities. Our model accounts for the effect of imperfect spectrum sensing, which depends on path-loss, shadowing, and small-scale fading of the link from the primary transmitter to the CU; the interweave and underlay modes or CR operation, which determine the transmit powers of the CUs; and time-correlated shadowing and fading of the links from the CUs to the PU-Rx. It leads to expressions for the probability distribution function, level crossing rate, and average exceedance duration. The impact of cooperative spectrum sensing is also characterized. We validate the model by applying it to redesign the primary exclusive zone to account for the time-varying nature of interference.

Reliability Assessment of a Storm Water Drain Network

Most of the cities in India are undergoing rapid development in recent decades, and many rural localities are undergoing transformation to urban hotspots. These developments have associated land use/land cover (LULC) change that effects runoff response from catchments, which is often evident in the form of increase in runoff peaks, volume and velocity in drain network. Often most of the existing storm water drains are in dilapidated stage owing to improper maintenance or inadequate design. The drains are conventionally designed using procedures that are based on some anticipated future conditions. Further, values of parameters/variables associated with design of the network are traditionally considered to be deterministic. However, in reality, the parameters/variables have uncertainty due to natural and/or inherent randomness. There is a need to consider the uncertainties for designing a storm water drain network that can effectively convey the discharge. The present study evaluates performance of an existing storm water drain network in Bangalore, India, through reliability analysis by Advance First Order Second Moment (AFOSM) method. In the reliability analysis, parameters that are considered to be random variables are roughness coefficient, slope and conduit dimensions. Performance of the existing network is evaluated considering three failure modes. The first failure mode occurs when runoff exceeds capacity of the storm water drain network, while the second failure mode occurs when the actual flow velocity in the storm water drain network exceeds the maximum allowable velocity for erosion control, whereas the third failure mode occurs when the minimum flow velocity is less than the minimum allowable velocity for deposition control. In the analysis, runoff generated from subcatchments of the study area and flow velocity in storm water drains are estimated using Storm Water Management Model (SWMM). Results from the study are presented and discussed. The reliability values are low under the three failure modes, indicating a need to redesign several of the conduits to improve their reliability. This study finds use in devising plans for expansion of the Bangalore storm water drain system. (C) 2015 The Authors. Published by Elsevier B.V.

Impact calculator

Evaluate the efficiency of your change initiative The Impact Calculator can be used to demonstrate the impact of a process redesign or system implementation by quantifying the tangible benefits or efficiency gains that can be derived from it: identifying and recording the efficiency savings and costs of a process redesign determine if and when a return on investment (ROI) is made identify and measure as many benefits as you wish quantifying efficiency savings in monetary and non-monetary terms

Experiments with a laser interferometric gravitational wave antenna

Sources and effects of astrophysical gravitational radiation are explained briefly to motivate discussion of the Caltech 40 meter antenna, which employs laser interferometry to monitor proper distances between inertial test masses. Practical considerations in construction of the apparatus are described. Redesign of test mass systems has resulted in a reduction of noise from internal mass vibrations by up to two orders of magnitude at some frequencies. A laser frequency stabilization system was developed which corrects the frequency of an argon ion laser to a residual fluctuation level bounded by the spectral density √s_v(f) ≤ 60µHz/√Hz, at fluctuation frequencies near 1.2 kHz. These and other improvements have contributed to reducing the spectral density of equivalent gravitational wave strain noise to √s_h(f)≈10^(-19)/√ Hz at these frequencies.

Finally, observations made with the antenna in February and March of 1987 are described. Kilohertz-band gravitational waves produced by the remnant of the recent supernova are shown to be theoretically unlikely at the strength required for confident detection in this antenna (then operating at poorer sensitivity than that quoted above). A search for periodic waves in the recorded data, comprising Fourier analysis of four 105-second samples of the antenna strain signal, was used to place new upper limits on periodic gravitational radiation at frequencies between 305 Hz and 5 kHz. In particular, continuous waves of any polarization are ruled out above strain amplitudes of 1.2 x 10^(-18) R.M.S. for waves emanating from the direction of the supernova, and 6.2 x 10^(-19) R.M.S. for waves emanating from the galactic center, between 1.5 and 4 kilohertz. Between 305 Hz and 5kHz no strains greater than 1.2 x 10^(-17) R.M.S. were detected from either direction. Limitations of the analysis and potential improvements are discussed, as are prospects for future searches.

Redesenho urbanístico de assentamentos informais com vistas à conservação da água e sustentabilidade ambiental.

Essa Tese apresenta um framework para implementação de redesenho urbanístico de assentamentos informais no contexto da corrente atual do planejamento urbano integrado aos dos recursos hídricos, focado na conservação da água e na sustentabilidade ambiental. Entre outros, sugere-se a implantação do desenho urbanístico de forma participativa e colaborativa. Apresenta-se, de forma ilustrativa proposta de redesenho para a comunidade da Vila Cascatinha localizada na Baixada de Jacarepaguá, Rio de Janeiro, região de expansão da cidade, que serviu como objeto de estudo. A área do assentamento é de indefinição fundiária e atualmente é ocupada por aproximadamente 900 famílias. O framework baseia-se na corrente do urbanismo de baixo impacto, sobretudo do Low Impact Urban Design and Devolopment (LIUDD). Os dispositivos são implantados na escala local, de forma descentralizada para a conservação e manejo das águas pluviais no meio urbano. A pesquisa está inserida no Projeto HIDROCIDADES, desenvolvido dentro dos princícpios da metodologia de pesquisa-ação proposta por Thiollent. Foi realizado trabalho de campo e entrevistas guiadas, tendo sido identificado um percentual expressivo de moradores descendentes de antigos pequenos produtores agrícolas. Na pesquisa, moradores elencaram os principais problemas do assentamento. Além disso, foram diagnosticadas potencialidades dos moradores, dentro do conceito de Tecnologia Social. A prospecção entre os moradores também procurou verificar, em um contexto de colaboração, o conhecimento e a aderência dos moradores às estruturas urbanísticas praticadas no contexto da corrente Desenho Urbano de Baixo Impacto. Ao final deste processo foi gerada proposta de reurbanização sustentável do assentamento estudado, bem como proposta de moradias coletivas sustentáveis. Guardando as devidas especificidades, espera-se que a proposta apresentada possa ser aplicada a outros assentamentos de paisagem similar.

Metaheurística para o Problema de Planejamento de Redes de Transmissão de Energia Elétrica com Redimensionamento

Com o passar do tempo, a demanda elétrica de diversas áreas varia tornando necessária a construção de novos geradores elétricos e a expansão da rede de transmissão de energia elétrica. Nesta dissertação, focamos no problema de expansão da rede de transmissão, assumindo que novos geradores estão construídos para suprir as novas demandas. Essa expansão exige altos investimentos que precisam ser cuidadosamente planejados. O problema pode ser modelado como um problema de otimização não linear inteira mista e pertence à classe dos problemas NP-difíceis. Desta forma, uma abordagem heurística pode ser adequada para a sua solução pois pode vir a fornecer boas soluções em tempo computacional aceitável. Esta dissertação se propõe a apresentar um estudo do problema de planejamento da expansão de redes de transmissão de energia elétrica estático e multiestágio. Mostramos o que já existe na literatura para o que é chamado de problema sem redimensionamento e as inovações feitas por nós para o problema com redimensionamento. Quanto aos métodos de solução, utilizamos a metaheurística GRASP para o problema estático e combinamos o GRASP com o procedimento Backward-Forward quando falamos em problema multiestágio. Nesta dissertação comparamos os resultados computacionais obtidos com resultados encontrados na literatura.

A inclusão de alunos com deficiência na UEPB: uma avaliação do Programa de Tutoria Especial

O presente estudo tem por objetivo avaliar as contribuições do Programa de Tutoria Especial da Universidade Estadual da Paraíba (UEPB) para a permanência e bom desempenho acadêmico dos seus alunos com deficiência no ensino superior. A pesquisa realizada, nessa Instituição de Ensino Superior, nos cursos de Pedagogia, História, Filosofia, Comunicação Social, Serviço Social, Direito e Física, contou como sujeitos: alunos com deficiência, seus respectivos tutores especiais, professores e a coordenadora do referido Programa. A investigação foi desenvolvida se utilizando de uma abordagem quantitativa e qualitativa, sendo do tipo exploratória e assumindo a forma de estudo de caso. Os procedimentos metodológicos de coleta de dados foram: análise documental, aplicação de questionários, entrevistas e registro de observações do comportamento. A pesquisa documental foi realizada durante todo o percurso da investigação, mediante acesso e análise de documentos e informações do Programa de Tutoria Especial. O questionário foi usado para a identificação e caracterização socioeconômica dos alunos com deficiência. A entrevista semiestruturada, foi aplicada aos vinte e seis sujeitos da pesquisa. Já, as sessões de observação do comportamento dos participantes foram conduzidas por meio de vinte sessões distribuídas em sala de aula e em atendimentos pedagógicos individualizados do Programa. Neste momento, procedemos, de maneira específica, ao estudo de caso de dois alunos com deficiência, integrantes da amostra dos sujeitos das entrevistas. Os resultados das entrevistas indicaram, dentre outros dados, que os sujeitos da pesquisa avaliaram o Programa de Tutoria Especial de forma positiva, alegando que o mesmo contribui tanto para a permanência dos alunos com deficiência na academia, quanto para o seu bom desempenho acadêmico. Na análise dos registros de observação, assim como das entrevistas, detectamos aspectos do Programa que ratificam, pontos que contrariam e pontos que necessitam ser incorporados à sua Resolução de criação (Resolução CONSEPE/UEPB N 013, de 07/07/2006). Os dados apontaram, portanto, a necessidade desta Resolução ser revista e reformulada para contemplar as novas demandas da dinâmica do Programa. Por fim, diante dos achados da investigação, levantamos a tese de que o Programa de Tutoria Especial da UEPB é um tipo de Atendimento Educacional Especializado (AEE) no ensino superior, com características e adaptações peculiares, ocorrendo de maneira diferenciada do AEE criado pelo Ministério da Educação, Cultura e Desporto (MEC) para a educação básica. Assim sendo, esta experiência da UEPB, sendo pioneira dentre as universidades brasileiras, poderá servir como uma proposta a ser socializada com outras universidades do país, uma vez que o MEC ainda não dispõe de uma política de AEE para o ensino superior.

Implantação da assistência humanizada ao parto em Juiz de Fora (1998-2001)

Trata-se de um estudo de natureza histórico-social do tempo presente. O objeto é a implantação do modelo humanizado de assistência ao parto em Juiz de Fora, Minas Gerais, no período de 1998 a 2001. Os objetivos do estudo são: descrever as circunstâncias de criação da Comissão Interinstitucional para Redução da Cesariana e Proteção ao Parto Normal; analisar as estratégias da Comissão Interinstitucional para Redução da Cesariana e Proteção ao Parto Normal e a implantação do modelo humanizado de assistência ao parto na cidade de Juiz de Fora; analisar os efeitos da participação das enfermeiras obstétricas no campo obstétrico. O estudo apoia-se nas noções teóricas de campo, habitus, poder simbólico, luta simbólica e capital do sociólogo Pierre Bourdieu. Na análise foi realizada a triangulação de dados, através da articulação da documentação oral e escrita à luz das noções teóricas. A criação da Comissão Interinstitucional para Redução da Cesariana e Proteção ao Parto Normal foi uma estratégia elaborada na esfera da gestão pública da cidade. Teve início no dia 26 de fevereiro de 1998 no Departamento de Programação e Acompanhamento SMS/JF. As estratégias utilizadas pela Comissão para implantar o modelo humanizado de assistência ao parto foram: a elaboração e a implantação de um Plano de Ação com ações de informações e sensibilização dos médicos e da população; formação de Recursos Humanos para implantar as práticas obstétricas humanizadas, com a criação do Curso de Especialização em Enfermagem Obstétrica; e a reconfiguração do campo obstétrico com o projeto de criação da Casa de Parto. Como efeitos da implantação do modelo humanizado de assistência ao parto foi evidenciado que, a partir de 2001, enfermeiras obstétricas, egressas do Curso de Especialização em Enfermagem Obstétrica/Universidade Federal de Juiz de Fora (UFJF), começaram a ocupar espaços nas salas de partos de duas Maternidades da cidade, e em 2005, foi criada a Lei Municipal do Acompanhante.

Redesigning the design process through interactive simulation: A case study of life-cycle engineering in jet engine conceptual design

Many aerospace companies are currently making the transition to providing fully-integrated product-service offerings in which their products are designed from the outset with life-cycle considerations in mind. Based on a case study at Rolls-Royce, Civil Aerospace, this paper demonstrates how an interactive approach to process simulation can be used to support the redesign of existing design processes in order to incorporate life-cycle engineering (LCE) considerations. The case study provides insights into the problems of redesigning the conceptual stages of a complex, concurrent engineering design process and the practical value of process simulation as a tool to support the specification of process changes in the context of engineering design. The paper also illustrates how development of a simulation model can provide significant benefit to companies through the understanding of process behaviour that is gained through validating the behaviour of the model using different design and iteration scenarios. Keywords: jet engine design; life-cycle engineering; LCE; process change; design process simulation; applied signposting model; ASM. Copyright © 2011 Inderscience Enterprises Ltd.

Reusing steel and aluminum components at end of product life.

Reusing steel and aluminum components would reduce the need for new production, possibly creating significant savings in carbon emissions. Currently, there is no clearly defined set of strategies or barriers to enable assessment of appropriate component reuse; neither is it possible to predict future levels of reuse. This work presents a global assessment of the potential for reusing steel and aluminum components. A combination of top-down and bottom-up analyses is used to allocate the final destinations of current global steel and aluminum production to product types. A substantial catalogue has been compiled for these products characterizing key features of steel and aluminum components including design specifications, requirements in use, and current reuse patterns. To estimate the fraction of end-of-life metal components that could be reused for each product, the catalogue formed the basis of a set of semistructured interviews with industrial experts. The results suggest that approximately 30% of steel and aluminum used in current products could be reused. Barriers against reuse are examined, prompting recommendations for redesign that would facilitate future reuse.

Facets of prior experience and the effectiveness of inclusive design

Research in inclusive design has shown the importance of prior experience for the usability of interactive products. Prior experience, however, is an ill-defined and inconsistently used construct. A number of different definitions and operationalisations of experience exist, but the differing power of these operationalisations to predict the usability of products for older users has rarely been investigated systematically. This study seeks to fill that gap. It is argued that the construct of experience has at least three components. It is proposed that two of these components, exposure and competence, are directly relevant for the current discussion about prior experience in inclusive design and that they can predict to different degrees the usability of a product for older users. In an empirical study, these facets of expertise are each operationalised on three levels of specificity and their impact on usability is assessed. The results show that measures of competence predict usability variables more strongly than measures of exposure and that levels of medium and high specificity are the best predictors. The application of inclusive design principles to a redesigned version of a ticket vending machine-although not resulting in a difference of overall usability-changed the impact of prior experience on usability measures implying an enhanced inclusiveness of the redesign with regard to prior experience. The implications of these findings for the effectiveness of inclusive design for older users are discussed. © 2013 Springer-Verlag Berlin Heidelberg.

CLF based designs with robustness to dynamic input uncertainties

The problem of robust stabilization of nonlinear systems in the presence of input uncertainties is of great importance in practical implementation. Stabilizing control laws may not be robust to this type of uncertainty, especially if cancellation of nonlinearities is used in the design. By exploiting a connection between robustness and optimality, "domination redesign" of the control Lyapunov function (CLF) based Sontag's formula has been shown to possess robustness to static and dynamic input uncertainties. In this paper we provide a sufficient condition for the domination redesign to apply. This condition relies on properties of local homogeneous approximations of the system and of the CLF. We show that an inverse optimal control law may not exist when these conditions are violated and illustrate how these conditions may guide the choice of a CLF which is suitable for domination redesign. © 1999 Elsevier Science B.V. All rights reserved.

Aerodynamic design of high end wall angle turbine stages- part II: Experimental verification

An experimental investigation of a turbine stage featuring very high end wall angles is presented. The initial turbine design did not achieve a satisfactory performance and the difference between the design predictions and the test results was traced to a large separated region on the rear suction-surface. To improve the agreement between computational fluid dynamics (CFD) and experiment, it was found necessary to modify the turbulence modeling employed. The modified CFD code was then used to redesign the vane, and the changes made are described. When tested, the performance of the redesigned vane was found to have much closer agreement with the predictions than the initial vane. Finally, the flowfield and performance of the redesigned stage are compared to a similar turbine, designed to perform the same duty, which lies in an annulus of moderate end wall angles. A reduction in stage efficiency of at least 2.4% was estimated for the very high end wall angle design. © 2014 by ASME.

基于DSP的烟支重量控制系统的设计

本文介绍了对Passim8K型卷烟机重量控制系统的改造。采用TI公司的TMS320LF2812DSP作为中央处理器,实现了烟支的在线重量检测和控制,并增加了烟支紧头跟踪功能。改造后的重量控制系统检测精度高,体积小,性能稳定,运行可靠。