This study aims to design a Shunt Semi-Active Power Factor Correction Circuits , which can be applied to high power circuit by low switching frequency. The designed circuit can avoid power loss working with high switching frequency when using the method of active power factor correction .The experimental configuration based on DSP is applied to a compressor of air conditioner with varied load. The simulation check the developed circuit using Ispice . Both of the experimental and simulation results have guaranteed the derived configuration reach the expected goals.

[pt] Uma metodologia eficiente e segura é proposta para prever a propagação de trincas de fadiga sob carregamento complexo em estruturas bidimensionais com geometria genérica. Primeiro, o caminho da trinca (em geral curvo) e os fatores de intensidade de tensão KI(a) e KII(a) ao longo do comprimento da trinca a são calculados num programa de elementos finitos especialmente desenvolvido para este fim, o Quebra2D. Estes cálculos são feitos usando pequenos incrementos especificáveis no tamanho da trinca e técnicas de remalhamento automatizadas. Os valores de KI(a) são usados como dados de entrada num programa de previsão de vida à fadiga, o ViDa. Esse programa foi desenvolvido para prever a iniciação e a propagação de trincas 1D e 2D sob carregamento complexo por todos os métodos clássicos, incluindo SN, eN e IIW (estruturas soldadas) para a iniciação da trinca, e o método da/dN para a propagação. Em particular, o módulo que propaga a trinca aceita qualquer expressão de KI(a) e qualquer regra da/dN, e usa o método DKrms ou CCC (crescimento ciclo-a-ciclo) para prever a propagação de trincas uni e bidimensionais sob carregamento complexo. A análise numérica proposta foi verificada através de vários experimentos representativos, cuja metodologia experimental é discutida em detalhes. / [en] A reliable and cost effective two-phase methodology is proposed to predict fatigue crack propagation in generic two-dimensional structural components under complex loading. First, the fatigue crack path and its stress intensity factor are calculated in a specialized finite- element software, using small crack increments. Numerical methods are used to calculate the crack propagation path, based on the computation of the crack incremental direction, and the stress-intensity factors KI, from the finite element response. Then, an analytical expression is adjusted to the calculated KI(a) values, where a is the length along the crack path. This KI(a) expression is used as an input to a powerful general purpose fatigue design software based on the local approach, developed to predict both initiation and propagation fatigue lives under complex loading by all classical design methods, including the SN, the eN and the IIW (for welded structures) to deal with crack initiation, and the da/dN to treat propagation problems. In particular, its crack propagation module accepts any KI expression and any da/dN rule, using the DKrms or the cycle-by-cycle propagation methods to deal with one and twodimensional crack propagation under complex loading. If requested, this latter method may include overload-induced crack retardation effects. This two-phase methodology is experimentally validated by fatigue tests on compact tension and bending single edge notch specimens, modified with holes positioned to attract or to deflect the cracks.

Esta pesquisa consistiu na verificação do comportamento do reator UASB de bancada (volume igual a 10,5 litros), quando submetido a variações senoidais de vazão afluente, comparando-se com a eficiência no seu funcionamento com vazão constante, através de análises de amostras de afluentes e efluentes. O reator UASB utilizado foi montado no Laboratório de Processos Biológicos da EESC-USP dentro de uma câmara com temperatura constante de 30 ± 3°C, e alimentado com esgoto sintético, com DQO de 500 mg/l, 750 mg/l e 1000 mg/l. O reator foi inoculado em abril de 1999, com 3,5 litros de lodo anaeróbio proveniente de um reator compartimentado, também situado na EESC-USP. Devido à dificuldade de atingir um valor esperado para a eficiência de remoção de Matéria orgânica, foi dada nova partida no reator, em julho de 1999, desta vez com lodo proveniente de outro UASB. Após a segunda partida, o reator operou com vazão constante e DQO afluente em torno de 500 mg/l até setembro de 1999, com média de remoção de DQO bruta de 75% no período, passando-se, então, à fase de variação senoidal de vazão de forma que o máximo e o mínimo fossem de ±30%, ±45% e ±60% da vazão média. Para este regime, obteve-se 80% de eficiência média de remoção de DQO bruta. Os valores de pH, alcalinidade e ácidos voláteis foram praticamente constantes durante a operação. Os perfis de remoção de DQO ao longo do dia mostraram uma pequena queda na eficiência do reator, aproximadamente 1,5 vezes o tempo de detenção hidráulica médio (8 horas), após os máximos de vazão para o regime de variação de vazão de ±30% e ±45% e 2,5 vezes o tempo de detenção hidráulica médio, para variação e ±60%. O mesmo experimento foi repetido para DQO afluente de 1000 mg/l e obteve-se, em média, eficiências de 65% de remoção de DQO. / This research consisted in the UASB reactor performance verification when it was submitted to sine-based variations of loading rate, in comparison to its normal operation. The UASB reactor used was set up at the Biological Process Laboratory of EESC-USP, inside a camera with temperature of 30°C ± 3°C. It was fed with synthetic sewage (COD = 500, 750 and 1000 mg/l). After start-up, the reactor was operated with constant loading rate (COD = 500 mg/l) until September 1999. The organic matter removal average in this period was 75%. Then, it was initiated the phase of sine-based variation loading rate (±30%, ±45% and ±60%). In this regime, it was obtained a medium gross COD removal efficiency of 80%. The pH values, alkalinity and volatile acids were practically constant during the operation. The COD removal profiles during the day showed a subtle fall in the reactor efficiency after 1.5 times the medium hydraulic detection time, for the loading rate variation of ±30% and ±45%. For ±60% variation, the answer time was approximately 2.5 times the medium hydraulic detection time. The efficiency of gross COD removal stay however over 78,53% until the experiment 9, witch showed that the reactor can stand the loading rate variations. The efficiency of filtered COD removal decreased on the second experiment, came back to the initial values and decreased again. The values of variation didn\'t surpass 6,6% for gross COD and 8,43% for filtered COD.

For decades, structural engineers have been using various conventional design approaches for assessing the strength and stability of framed structures for various loads. Today, engineers are still designing without some critical information to insure that their stability assessment yields a safe design for the life of the structure with consideration for extreme loads. Presented in this thesis is new critical information provided from the study of stability analysis and design of steel framed structures accounting for extreme loads associated to load patterns that may be experienced during their lifetime. It is conducted in five main parts. A literature survey is first carried out reviewing the previous research of analyzing frame stability including the consideration of initial geometric imperfections, and also evaluating research of the analysis and design of the increased usage of cold-formed steel (CFS) storage racks. Secondly, the elastic buckling loads for single-storey unbraced steel frames subjected to variable loading is extended to multi-storey unbraced steel frames. The formulations and procedures are developed for the multi-storey unbraced steel frames subjected to variable loading using the storey-based buckling method. Numerical examples are presented as comparisons to the conventional proportional loading approach and to demonstrate the effect of connection rigidity on the maximum and minimum frame-buckling loads. Thirdly, the lateral stiffness of axially loaded columns in unbraced frames accounting for initial geometric imperfections is derived based on the storey-based buckling. A practical method of evaluating column effective length factor with explicit accounting for the initial geometric imperfections is developed and examined using numerical examples. The fourth part is an investigation of the stability for multi-storey unbraced steel frames under variable loading with accounting for initial geometric imperfections. Finally, the stability of CFS storage racks is studied. The effective length factor of CFS storage racks with accounting for the semi-rigid nature of the beam-to-column connections of such structures are evaluated based on experimental data. A parametric study on maximum and minimum frame-buckling loads with or without accounting for initial geometric imperfections is conducted. The proposed stability analysis of multi-storey unbraced frames subjected to variable loading takes into consideration the volatility of live loads during the life span of structures and frame buckling characteristics of the frames under any possible load pattern. From the proposed method, the maximum and minimum frame-buckling loads together with their associated load patterns provides critical information to clearly define the stability capacities of frames under extreme loads. This critical information in concern for the stability of structures is generally not available through a conventional proportional loading analysis. This study of work ends with an appropriate set of conclusions.

For decades, structural engineers have been using various conventional design approaches for assessing the strength and stability of framed structures for various loads. Today, engineers are still designing without some critical information to insure that their stability assessment yields a safe design for the life of the structure with consideration for extreme loads. Presented in this thesis is new critical information provided from the study of stability analysis and design of steel framed structures accounting for extreme loads associated to load patterns that may be experienced during their lifetime. It is conducted in five main parts. A literature survey is first carried out reviewing the previous research of analyzing frame stability including the consideration of initial geometric imperfections, and also evaluating research of the analysis and design of the increased usage of cold-formed steel (CFS) storage racks. Secondly, the elastic buckling loads for single-storey unbraced steel frames subjected to variable loading is extended to multi-storey unbraced steel frames. The formulations and procedures are developed for the multi-storey unbraced steel frames subjected to variable loading using the storey-based buckling method. Numerical examples are presented as comparisons to the conventional proportional loading approach and to demonstrate the effect of connection rigidity on the maximum and minimum frame-buckling loads. Thirdly, the lateral stiffness of axially loaded columns in unbraced frames accounting for initial geometric imperfections is derived based on the storey-based buckling. A practical method of evaluating column effective length factor with explicit accounting for the initial geometric imperfections is developed and examined using numerical examples. The fourth part is an investigation of the stability for multi-storey unbraced steel frames under variable loading with accounting for initial geometric imperfections. Finally, the stability of CFS storage racks is studied. The effective length factor of CFS storage racks with accounting for the semi-rigid nature of the beam-to-column connections of such structures are evaluated based on experimental data. A parametric study on maximum and minimum frame-buckling loads with or without accounting for initial geometric imperfections is conducted. The proposed stability analysis of multi-storey unbraced frames subjected to variable loading takes into consideration the volatility of live loads during the life span of structures and frame buckling characteristics of the frames under any possible load pattern. From the proposed method, the maximum and minimum frame-buckling loads together with their associated load patterns provides critical information to clearly define the stability capacities of frames under extreme loads. This critical information in concern for the stability of structures is generally not available through a conventional proportional loading analysis. This study of work ends with an appropriate set of conclusions.

Esta pesquisa consistiu na verificação do comportamento do reator UASB de bancada (volume igual a 10,5 litros), quando submetido a variações senoidais de vazão afluente, comparando-se com a eficiência no seu funcionamento com vazão constante, através de análises de amostras de afluentes e efluentes. O reator UASB utilizado foi montado no Laboratório de Processos Biológicos da EESC-USP dentro de uma câmara com temperatura constante de 30 ± 3°C, e alimentado com esgoto sintético, com DQO de 500 mg/l, 750 mg/l e 1000 mg/l. O reator foi inoculado em abril de 1999, com 3,5 litros de lodo anaeróbio proveniente de um reator compartimentado, também situado na EESC-USP. Devido à dificuldade de atingir um valor esperado para a eficiência de remoção de Matéria orgânica, foi dada nova partida no reator, em julho de 1999, desta vez com lodo proveniente de outro UASB. Após a segunda partida, o reator operou com vazão constante e DQO afluente em torno de 500 mg/l até setembro de 1999, com média de remoção de DQO bruta de 75% no período, passando-se, então, à fase de variação senoidal de vazão de forma que o máximo e o mínimo fossem de ±30%, ±45% e ±60% da vazão média. Para este regime, obteve-se 80% de eficiência média de remoção de DQO bruta. Os valores de pH, alcalinidade e ácidos voláteis foram praticamente constantes durante a operação. Os perfis de remoção de DQO ao longo do dia mostraram uma pequena queda na eficiência do reator, aproximadamente 1,5 vezes o tempo de detenção hidráulica médio (8 horas), após os máximos de vazão para o regime de variação de vazão de ±30% e ±45% e 2,5 vezes o tempo de detenção hidráulica médio, para variação e ±60%. O mesmo experimento foi repetido para DQO afluente de 1000 mg/l e obteve-se, em média, eficiências de 65% de remoção de DQO. / This research consisted in the UASB reactor performance verification when it was submitted to sine-based variations of loading rate, in comparison to its normal operation. The UASB reactor used was set up at the Biological Process Laboratory of EESC-USP, inside a camera with temperature of 30°C ± 3°C. It was fed with synthetic sewage (COD = 500, 750 and 1000 mg/l). After start-up, the reactor was operated with constant loading rate (COD = 500 mg/l) until September 1999. The organic matter removal average in this period was 75%. Then, it was initiated the phase of sine-based variation loading rate (±30%, ±45% and ±60%). In this regime, it was obtained a medium gross COD removal efficiency of 80%. The pH values, alkalinity and volatile acids were practically constant during the operation. The COD removal profiles during the day showed a subtle fall in the reactor efficiency after 1.5 times the medium hydraulic detection time, for the loading rate variation of ±30% and ±45%. For ±60% variation, the answer time was approximately 2.5 times the medium hydraulic detection time. The efficiency of gross COD removal stay however over 78,53% until the experiment 9, witch showed that the reactor can stand the loading rate variations. The efficiency of filtered COD removal decreased on the second experiment, came back to the initial values and decreased again. The values of variation didn\'t surpass 6,6% for gross COD and 8,43% for filtered COD.