Actuators for smart applications

Actuator manufacturers are developing promising technologies\ud which meet high requirements in performance, weight and\ud power consumption. Conventionally, actuators are characterized\ud by their displacement and load performance. This hides the\ud dynamic aspects of those actuation solutions. Work per weight\ud performed by an actuation mechanism and the time needed to\ud develop this mechanical energy are by far more relevant figures.\ud Based on these figures, a selection process was developed.\ud With time and energy constraints, it highlights the most\ud weight efficient actuators. This process has been applied to the\ud Gurney flap technology used as a morphing concept for rotorblades.\ud Three control schemes were considered and simulations\ud were performed to investigate the mechanical work required. It\ud brought forward piezoelectric stack actuators as the most effective\ud solution in the case of an actively controlled rotorblade. The\ud generic nature of the procedure allows to use it for a wide range\ud of applications

Síntese e caracterização de cristais liquidos tipo bastão de hockey

TCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências Físicas e Matemáticas. Curso de Química.Este trabalho tem como objetivo geral a síntese de cristais líquidos termotrópicos, com forma semelhante a bastões de hockey contendo o heterociclo 1,3,4 oxadiazol, e o estudo sistemático envolvendo a relação da estrutura molecular e comportamento mesomórfico bem como o fotofísico. O acesso à tais compostos envolve a reação de acoplamento cruzado de Sonogashira. As mesofases foram caracterizadas por observações ópticas de microscopia óptica de luz polarizada (MOLP) e medidas calorimétricas com um Calorímetro Diferencial de Varredura (DSC). As texturas observadas são típicas de cristais líquidos calamíticos. Todos os compostos foram caracterizados por métodos espectroscópicos de IV, UV, RMN de 1H e 13C

Caracterização das propriedades mecânicas e metalúrgicas de uma junta de aço Astm A36 soldado pelo processo de arco submerso (SAW) com diferentes aportes térmicos

A soldagem de materiais é utilizada em grande escala na indústria metalmecânica, sendo a maneira mais econômica para unir metais, sendo assim, desafia constantemente o setor industrial na busca por processos de fabricação que apresentem maior produtividade, com alta qualidade e custos reduzidos. Neste contexto, o processo de arco submerso (submerged arc welding - SAW) se destaca por sua alta produtividade e boa qualidade da junta soldada, sendo muito utilizado na soldagem de perfis estruturais. Dentre os aços estruturais existentes, um dos mais utilizados e conhecidos é o ASTM A36, que é classificado como um aço carbono de média resistência mecânica. Este aço é muito utilizado na confecção de perfis estruturais em diversos setores da indústria metalmecânica como na construção civil. A velocidade de soldagem é um dos principais parâmetros do processo de soldagem, que influencia diretamente na produtividade do processo, assim como nas propriedades mecânicas e metalúrgicas da junta soldada. A utilização de diferentes velocidades de soldagem geram diferentes aportes térmicos, que pode ser entendida como a quantidade de calor envolvido no momento da soldagem, ou seja, diferentes aportes térmicos, geram diferentes taxas de extração de calor da poça de fusão para o metal de base a ser soldado. Estas diferentes condições de extração de calor ou de resfriamento, poderão produzir distintas transformações microestruturais, e estas transformações podem ser prejudiciais às propriedades mecânicas, principalmente à tenacidade na zona afetada pelo calor (ZAC). O presente estudo tem por objetivo aprofundar o conhecimento sobre o efeito de diferentes velocidades de soldagem nas propriedades mecânicas e metalúrgicas de uma junta do aço ASTM A36 soldado pelo processo de SAW. A avaliação das propriedades mecânicas e metalúrgicas será definida através de ensaios de dobramento, tração da junta soldada, ensaios de Charpy-V e caracterizações microestruturais, além de perfis de microdureza.The welding of materials is used on large scale in the metal industry, being the most economical way to join metals; therefore, it constantly challenges the industrial sector to search for manufacturing processes that present higher productivity, with high quality and reduced costs. In this context, the submerged arc welding process (SAW) stands out for its high productivity and good quality of the welded joint and is widely used in the welding of structural profiles. Among the existing structural steel, one of the most used and known is ASTM A36 – which is classified as a carbon steel with a medium mechanical strength. This steel is widely used in the manufacture of structural profiles in various sectors of the metalworking industry as well as in constructions. The welding speed is one of the main parameters of the welding process. This influences directly in the productivity process as well as in the mechanical and metallurgical properties of the weld. Different welding speeds generate different heat inputs, and it can be understood as the amount of heat involved in the welding time. Since we have different heat inputs, we will generate different heat extraction rates from the weld pool to the base metal. These different heat extraction conditions or cooling conditions may produce different microstructural changes, and these changes may be harmful to mechanical properties, especially toughness in the heat affected zone (HAZ). This study aims to deepen the understanding on the effect of different welding speeds in the mechanical and metallurgical properties of steel joint ASTM A36 welded by the SAW process. The evaluation of the mechanical and metallurgical properties will be made through bending tests, tensile test of the welded joint, Charpy-V test to check the toughness, microstructural characterization, and microhardness profiles

CosmoHammer: Cosmological parameter estimation with the MCMC Hammer

We study the benefits and limits of parallelised Markov chain Monte Carlo (MCMC) sampling in cosmology. MCMC methods are widely used for the estimation of cosmological parameters from a given set of observations and are typically based on the Metropolis-Hastings algorithm. Some of the required calculations can however be computationally intensive, meaning that a single long chain can take several hours or days to calculate. In practice, this can be limiting, since the MCMC process needs to be performed many times to test the impact of possible systematics and to understand the robustness of the measurements being made. To achieve greater speed through parallelisation, MCMC algorithms need to have short auto-correlation times and minimal overheads caused by tuning and burn-in. The resulting scalability is hence influenced by two factors, the MCMC overheads and the parallelisation costs. In order to efficiently distribute the MCMC sampling over thousands of cores on modern cloud computing infrastructure, we developed a Python framework called CosmoHammer which embeds emcee, an implementation by Foreman-Mackey et al. (2012) of the affine invariant ensemble sampler by Goodman and Weare (2010). We test the performance of CosmoHammer for cosmological parameter estimation from cosmic microwave background data. While Metropolis-Hastings is dominated by overheads, CosmoHammer is able to accelerate the sampling process from a wall time of 30 hours on a dual core notebook to 16 minutes by scaling out to 2048 cores. Such short wall times for complex data sets opens possibilities for extensive model testing and control of systematics.Comment: Published version. 17 pages, 6 figures. The code is available at http://www.astro.ethz.ch/refregier/research/Software/cosmohamme

Dimensões e espaços da inovação social

DIMENSIONS AND SPACES OF SOCIAL INNOVATION. Following a period in which the idea of innovation was almost exclusively associated with the technological domain, the notion of social innovation has over the past few years gained increasing recognition and come to be used in a variety of contexts. In most of the of the market, usually without direct intervention by the State, and primarily aimed at social inclusion through the activity of the third sector. However, the conceptual discussion within the scope of Project LINKS has led us to further delimit the scope of the concept of social innovation, in order to define the conceptual framework of the research. Thus, we suggest that social innovation be regarded as consisting of any new response enjoying social recognition that both seeks and achieves social change while fulfilling three criteria: i) the satisfaction of human needs not met through market mechanisms; ii) the advancement of social inclusion; and iii) the empowerment of agents or actors that are actually or potentially subject to processes of social exclusion/marginalisation, thereby triggering changes of varying intensity in power relations. Having identified the central object of our research, it becomes indispensable to render operative the concept of social innovation, in order to produce a “roadmap” that makes it possible both to carry out a systematic comparative reading of the case studies and to define a set of indicators to be used in extensive analysis. In this paper, we begin by presenting the analytical dimensions that we consider to be most relevant: i) What is social innovation?; ii) Why is there social innovation?; iii) How does social innovation come about?; iv) Who produces social innovation?; and v) Where is social innovation produced? The discussion around these five analytical dimensions enables us to put forth a schematic roadmap that makes it possible to move forward in the analysis and interpretation of the actual social-geographical reality of social innovation. This roadmap emphasises certain aspects of social innovation, such as its nature, stimuli, resources and dynamics, as well as the characteristics of both its agents and its milieu, which, it is argued, tends to be characterised by a set of specificities that we can subsume under the concept of “plasticity”. In the second part of the article, we focus on the experience of microcredit in Portugal under the light of the conceptual framework presented in the first part. After a brief presentation of the concept and history of microcredit, we briefly describe its introduction in the national network space and then proceed to interpret it as an instance of social innovation – as such open to analysis according to the aforementioned dimensions. This interpretation of this particular example seems to confirm the heuristic value of the suggested roadmap, both in structuring the analysis of future case studies and in designing a set of indicators to be used in extensive research

Rometa e Julieu: uma paródia

Esta peça foi originalmente escrita em 1991 como um trabalho a ser apresen- tado durante o 35o aniversário da fundação do Colégio Monsenhor Adelmar da Mota Valença no municı́pio de Garanhuns/PE. O autor e demais atores cursavam, à época, a 8a série (atualmente o 9o ano do Ensino Fundamental II). A apresentação teatral ocorreu no dia 19 de outubro do referido ano, teve direção de Antônio Pacheco Neto e foi encenada no Centro Cultural Alfredo Leite Cavalcanti. O espetáculo foi vencedor nas categorias Melhor texto, Melhor Atriz e Melhor Ator e foi reapresentado no SESC Garanhuns em Novembro do mesmo ano. Uma referência a essa comemoração do citado colégio pode ser encontrada nos arquivos do jornal local do municı́pio de Garanhuns O Monitor de 09 de novembro de 1991. O autor reservou-se o direito de fazer algumas pequenas alterações nas ce- nas, falas e trilha sonora visando incorporar alguns elementos inexistentes na época em que a peça foi escrita. A essência, no entanto, mantém-se inalter- ada

Improving Memory Hierarchy Utilisation for Stencil Computations on Multicore Machines

Although modern supercomputers are composed of multicore machines, one can find scientists that still execute their legacy applications which were developed to monocore cluster where memory hierarchy is dedicated to a sole core. The main objective of this paper is to propose and evaluate an algorithm that identify an efficient blocksize to be applied on MPI stencil computations on multicore machines. Under the light of an extensive experimental analysis, this work shows the benefits of identifying blocksizes that will dividing data on the various cores and suggest a methodology that explore the memory hierarchy available in modern machines

Low-Power and Low-Noise Clock Generator for High-Speed ADCs

The rapid development of high-performance communication technologies reflects a clear trend in demanding requirements imposed on analog-to-digital converters (ADCs). Thus, it appears that these requirements imply higher frequencies not only for the input signal but also higher sampling frequencies, which translates into a higher sensitivity of the circuit to thermal noise and consequent increase in phase-noise. This arises as to the main purpose of this document, which will seek, as its main objective, the development of an architecture that allows the generation of multiple clock signals at high input frequencies with low jitter and low power dissipation to make ADCs more efficient and faster. This dissertation proposes an architecture implemented by a Clock Buffer that converts a differential input signal into a single-ended output signal, a Digital Buffer that transforms a sine wave into a square wave, and finally a Multi Clock Phase Generator (MPCG), consisting of Shift Registers. Both architectures are implemented in 130 nm CMOS technology. The architecture is powered by a LVDS signal with an amplitude of 200 mV and a frequency of 1 GHz, in order to output 8 square wave clock signals with an amplitude of 1.2 V and with a frequency of 125 MHz. The signals obtained at the output later will feed an architecture of 8 Time-Interleaved ADCs. The total area of the implemented circuit is about 8054.3 μm2, for a dissipated power of 5.3 mW and a jitter value of 1.13 ps. This new architecture will be aimed at all types of entities that work with devices that are made up of high-speed performance ADCs, to improve the operation of these same devices, making the processing from a continuous signal to a discrete signal as efficiently as possible.O rápido desenvolvimento das tecnologias de comunicação de alto desempenho, reflete uma tendência clara na exigência dos requisitos impostos aos conversores analógico-digital (ADCs). Deste modo, verifica-se que estes requisitos implicam elevadas frequências não só sinal de entrada, como também frequências elevadas de amostragem o que se traduz numa maior sensibilidade do circuito ao ruído térmico e consequente aumento ruído de fase. Esta problemática, surge como propósito principal deste documento, no qual se procurará, como objetivo principal, o desenvolvimento de uma arquitetura que permita gerar múltiplos sinais de relógio a altas frequências de entrada e períodos de amostragem, com um baixo jitter e baixa energia consumida de forma a tornar mais eficiente e rápido o funcionamento de ADCs. Ruido térmico. Esta dissertação propõe uma arquitetura composta por um amplificador de sinal de relógio que converte o duplo sinal de entrada num único sinal de saída, um amplificador digital que transforma uma onda sinusoidal numa onda quadrada e por fim um gerador de fase múltipla de sinais de relógio (MPCG), constituído por registos de deslocamento. Ambas as arquiteturas são implementadas em tecnologia CMOS de 130 nm. A arquitetura é alimentada com um sinal LVDS de 200 mV de amplitude e com uma frequência de 1 GHz, de forma a obter à saída 8 sinais de relógio de onda quadrada com uma amplitude de 1,2 V e com 125 MHz de frequência. Os sinais obtidos à saída posteriormente alimentarão uma arquitetura de 8 canais com multiplexagem temporal. A área total do circuito implementado é cerca de 8054,3 μm2, para uma potência dissipada de 5,3 mW e para um valor de jitter de 1,13 ps. Esta nova arquitetura será direcionada para todo o tipo de entidades que trabalham com dispositivos que são constituídos por ADCs de alta velocidade de desempenho, de forma a poder melhorar o funcionamento desses mesmos dispositivos, tornando o processamento de sinal continuo para sinal discreto o mais eficiente possível