Darbe nagrinėjamas juostinio konvejerio skaldos transportavimui projektavimas naudojant šiuolaikinę kompiuterinio projektavimo įrangą. Suprojektuotas ir sumodeliuotas SolidWorks kompiuterinio projektavimo sistemoje juostinis konvejeris skaldos transportavimui. Atliktas konvejerio laikančiųjų konstrukcijų stiprumo tyrimas, nustatyta, kad jų stiprumas pakankamas. Konvejerio pavara suprojektuota ir jos komponentų stiprumo tyrimai atlikti APM WinMashine programinio paketo pagalba. Pagrindinio konvejerio pavaros veleno stiprumo tyrimas parodė, kad jis yra tinkamas dirbti maksimalaus apkrovimo sąlygomis. Atlikti darbai parodė, kad naudojant kompiuterizuoto projektavimo sistemą SolidWorks, projektuose sumažėja klaidų skaičius, bei padidėja projektų atlikimo sparta. / The development of belt conveyor for transportation of macadam, using modern computer aided design (CAD), is analysed in the work. The conveyor was developed and modeled using CAD software SolidWorks. The analysis of the strength of conveyor frame was performed, it was rated that the strength of the frame is sufficient. The drive of the conveyor was developed and the analysis of the strength of its components was performed using APM WinMashine software. The analysis of the main conveyor shaft showed that it is suitable for operation under the conditions of maximum load. The performed works showed that using CAD system SolidWorks, number of design errors and design time decreases.

As South Africa's electricity consumption increases, Eskom is promoting Demand Side Management (DSM) to aid control of both the electricity consumption and its more effective usage, thereby delaying the need to construct new power stations, which pose large economic and environmental problems. Eskom has investigated various DSM strategies, such as load shifting, co-generation, alternative fuels and energy efficient processes, and has targeted the areas of load shifting and energy efficiency as prime areas for energy savings as they are relatively inexpensive and easy to implement. Pumps and fans form a large part of the industrial load. By improving the power usage of these devices with the use of variable speed drives, large energy savings may be achieved. To enable the energy usage of industrial loads to be evaluated, a test bed system which enables a variable speed drive to be loaded with a configurable load, was constructed. The test bed system forms a tool for evaluating and demonstrating the energy savings that are possible, by replacing fixed speed drives with variable speed drives when controlling the flow rate of pumps and fans. Results from the test bed system show that by using variable speed operation of pumps and fans, some energy savings are achievable when compared to existing methods of flow control. The achievable energy savings are dependent on the system properties and the duty cycle of the pump or fan system. / Thesis (M.Sc.)-University of Natal, Durban, 2001.

In high density magnetic hard disk drives, both fast track seeking and extremely accurate positioning of the read/write head are required. A new piezoelectric microactuator with transverse and lateral control of the head positioning system for high density hard disk drives is proposed. First, the structure of the new piezoelectric microactuator is illustrated. Design of the new microactuator is based on the axial deformation of piezoelectric elements for lateral motion and the bimorph actuation of piezoelectric elements for transverse motion. Next, a mathematical model of the microactuator system is defined. Static properties associated with the displacement of the system are evaluated and then dynamic system equations of the system are evaluated. Frequency response of the system is studied based on the dynamic system equations of the actuator system. Dynamic properties of the system with a variety of system parameters are evaluated. Finally, the controller design for the actuator is presented. Simulation results show that the new actuator achieves a maximum stroke of displacement of more than 0.2m with servo bandwidth of more than 5 kHz in the lateral direction and the flying height is decreased to less than 6 nm with resonance frequency of more than 100 kHz under the 0.5 % damping assumption. The new piezoelectric microactuator improves performance of high density hard disk drives by increasing servo bandwidth and decreasing flying height.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

O elemento químico neodímio (Nd) atualmente está em evidência pois é parte fundamental em aplicações produzidas por empresas ligadas a tecnologias limpas e de ponta. Porém, é classificado como crítico pelo departamento de energia dos EUA em função do monopólio chinês atuante em sua exploração e comercialização. Devido à crescente demanda frente à restrita disponibilidade, a recuperação deste metal está em ascensão. Uma das aplicações do neodímio é o ímã permanente de neodímio-ferro-boro, utilizado em hard disk drives (HDs) de computadores. Desta forma, este estudo visou caracterizar os ímãs provenientes de HDs de computadores e estabelecer uma rota de recuperação do neodímio por meio de processos mecânicos e hidrometalúrgicos. Por meio da pesagem dos HDs e seus ímãs obteve-se massa média de 3,04 g e 7,91 g para laptop e desktop, respectivamente, representando menos de 3% da massa total do HD. A desmagnetização foi atingida por meio de aquecimento até a temperatura de Curie, em torno de 312 °C, e a cominuição realizada em moinho de facas, onde foram obtidas três granulometrias classificadas em frações A, B e C. Qualitativamente as amostras, foram analisados por meio de difração de raios-X (DRX), onde a fase tetragonal Nd2Fe14B foi o constituinte dominante, e por meio de análise em microscópio eletrônico de varredura (MEV). Semi-quantitativamente os ímãs, seus revestimentos e o precipitado final foram avaliados por meio de espectrometria de fluorescência de raios-X (FRX). A composição média de 21,5% de neodímio e 65,1% de ferro em massa, além de outros elementos químicos, obtida por meio de espectrometria de emissão óptica com plasma (ICP-OES), mostrou teor de neodímio superior aos minérios explorados, tornando este resíduo interessante em relação à recuperação deste metal. O procedimento hidrometalúrgico adotado envolveu a lixiviação das amostras em ácido sulfúrico 2M e a variação de três parâmetros: razão sólido/líquido, temperatura e tempo, em dois níveis. Posteriormente foi realizada a precipitação seletiva por meio de NaOH, formando o duplo sal NaNd(SO4)2.nH2O. Os resultados mostraram que a lixiviação de neodímio atingiu eficiência média acima de 94%, porém todos os experimentos apresentaram material não lixiviado, majoritariamente composto por níquel e cobre. / The chemical element neodymium (Nd) currently is in evidence as it is a fundamental part in applications manufactured by clean and advanced technology companies. However, it is classified as critical by the United States Department of Energy due to Chinese monopoly in its exploration and commercialization. Due to increasing demand in contrast with scarce supply, the recovery of neodymium is growing. One of the applications of this metal is the neodymium-iron-boron permanent magnet, used in hard disk drives (HDDs) of computers. Therefore, this study aimed magnets characterizing from HDDs of computers and then establishing a recovery route for neodymium by mechanical and hydrometallurgical processes. By weighing the HDDs and their magnets it was obtained the average weight of 3.04 g and 7.91 g for laptop and desktop, respectively, representing less than 3% of the HDDs total mass. Demagnetizing was achieved by heating up to Curie temperature of around 312 °C, and the comminution in knives mill resulted in three granulometries classified into fractions A, B and C. Qualitatively, magnets were analyzed by X-ray diffraction (XRD), where the tetragonal phase Nd2Fe14B was the dominant constituent of the sample, and through analysis in a scanning electron microscope (SEM). Semi-quantitatively, the magnets, its covers, and the final precipitate were evaluated by X-ray fluorescence spectrometry (XRF). The average composition of neodymium and iron showed 21.5% and 65.1% by weight, respectively, among other chemical elements. This results were obtained by optical emission spectrometry (ICP-OES), representing a higher neodymium content compared to the ores content, which makes this waste interesting from a neodymium recovery point of view. The procedure adopted involved hydrometallurgical leaching of the samples in 2M sulfuric acid varying three parameters: liquid/solid ratio, temperature and time, each one on two levels. Subsequently, the selective precipitation by NaOH was performed to form the double salt NaNd(SO4)2.nH2O. The results showed that neodymium leaching efficiency reached above 94%, but the experiments showed as well some material left, mainly composed of nickel and copper.

Resumo: Em sistemas de bombeamento, a vazão solicitada à bomba nem sempre é constante, normalmente as bombas operam em rotação constante e para obter a variação da vazão, utilizam-se válvulas de estrangulamento na saída. Outro método utilizado é controlar a velocidade do motor através de inversores de freqüência, pois, a variação da vazão é diretamente proporcional à rotação do motor, proporcionando uma maior facilidade de controle e economia de energia, porém, interferindo na qualidade de energia elétrica. Neste contexto, a finalidade deste trabalho foi a comparação do consumo de energia elétrica para dois tipos de controle de vazão em sistemas de bombeamento: por válvula de estrangulamento ou por inversor de freqüência para dois tipos de motores: padrão e de alto rendimento. Comprovou-se que a simples troca de um motor padrão por um motor de alto rendimento gera uma redução de consumo de energia elétrica entre 32,45% a 33,42%, no caso estudado. A substituição do controle de vazão, da válvula de estrangulamento para o controle pelo inversor de freqüência trouxe uma economia de energia elétrica entre 47,18% a 52,22% em determinadas faixas. A substituição do controle de vazão pela válvula e motor padrão para o controle de vazão pelo inversor e motor de alto rendimento gerou uma economia de 67,03%. Para avaliar a influência dos programas de eficiência energética na qualidade da energia foram mensurados valores do fator de potência e dos níveis de distorção harmônica total de corrente e de tensão gerados através de três tipos de acionamento do motor trifásico: partida direta, partida suave e partida com inversor de freqüência, comparando-os com valores da norma brasileira (ANEEL) e de norma internacional (IEC). / Abstract: In pumping systems the flow requested of the pump is not always constant, normally the pumps operate in constant rotation and bottleneck valves are used in order to obtain the flow variation. Controlling the motor speed through variable frequency drives is another used method since the flow variation is directly proporcional to the motor rotation. In this report it was carried out a comparisson of electric power consumption in a pumping system with the flow control by bottleneck valve and by variable frequency drives in order to identify an economically viable range of use. The technical and economical viability of substituting a standard motor for a highperformance motor one was also analysed. It proved that the simple exchange of a standard motor for a high performance one, generates a reduction of electric power consumption between 32.45% a 33.42%, in the studied case. The replacement of the flow control of the bottleneck valve to the variable frequency drives brought a saving of electric power between 47.18% a 52.22% in certain ranges. The replacement of the flow control by the valve and standard motor for the variable frequency drives and the high performance motor generated an economy of 67.03%. It was mensuremented values of power factor and total harmonic distortion of current and voltage generated by three diferent types of starts: direct start, soft-start and variable speed drives start and compared with values of the Brazilian norm (ANEEL) and International norm (IEC) to appraise its influency in energy efficiency programs. / Orientador: Teófilo Miguel de Souza / Coorientador: Pedro Magalhães Sobrinho / Banca: Rubens Alves Dias / Banca: Jamil Haddad / Mestre

Made available in DSpace on 2014-06-11T19:30:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-07Bitstream added on 2014-06-13T20:20:27Z : No. of bitstreams: 1 mesquita_rp_me_guara.pdf: 1170750 bytes, checksum: fa765b6e1b242ea2391a24aa47efeb14 (MD5) / Eletrobras / Em sistemas de bombeamento, a vazão solicitada à bomba nem sempre é constante, normalmente as bombas operam em rotação constante e para obter a variação da vazão, utilizam-se válvulas de estrangulamento na saída. Outro método utilizado é controlar a velocidade do motor através de inversores de freqüência, pois, a variação da vazão é diretamente proporcional à rotação do motor, proporcionando uma maior facilidade de controle e economia de energia, porém, interferindo na qualidade de energia elétrica. Neste contexto, a finalidade deste trabalho foi a comparação do consumo de energia elétrica para dois tipos de controle de vazão em sistemas de bombeamento: por válvula de estrangulamento ou por inversor de freqüência para dois tipos de motores: padrão e de alto rendimento. Comprovou-se que a simples troca de um motor padrão por um motor de alto rendimento gera uma redução de consumo de energia elétrica entre 32,45% a 33,42%, no caso estudado. A substituição do controle de vazão, da válvula de estrangulamento para o controle pelo inversor de freqüência trouxe uma economia de energia elétrica entre 47,18% a 52,22% em determinadas faixas. A substituição do controle de vazão pela válvula e motor padrão para o controle de vazão pelo inversor e motor de alto rendimento gerou uma economia de 67,03%. Para avaliar a influência dos programas de eficiência energética na qualidade da energia foram mensurados valores do fator de potência e dos níveis de distorção harmônica total de corrente e de tensão gerados através de três tipos de acionamento do motor trifásico: partida direta, partida suave e partida com inversor de freqüência, comparando-os com valores da norma brasileira (ANEEL) e de norma internacional (IEC). / In pumping systems the flow requested of the pump is not always constant, normally the pumps operate in constant rotation and bottleneck valves are used in order to obtain the flow variation. Controlling the motor speed through variable frequency drives is another used method since the flow variation is directly proporcional to the motor rotation. In this report it was carried out a comparisson of electric power consumption in a pumping system with the flow control by bottleneck valve and by variable frequency drives in order to identify an economically viable range of use. The technical and economical viability of substituting a standard motor for a highperformance motor one was also analysed. It proved that the simple exchange of a standard motor for a high performance one, generates a reduction of electric power consumption between 32.45% a 33.42%, in the studied case. The replacement of the flow control of the bottleneck valve to the variable frequency drives brought a saving of electric power between 47.18% a 52.22% in certain ranges. The replacement of the flow control by the valve and standard motor for the variable frequency drives and the high performance motor generated an economy of 67.03%. It was mensuremented values of power factor and total harmonic distortion of current and voltage generated by three diferent types of starts: direct start, soft-start and variable speed drives start and compared with values of the Brazilian norm (ANEEL) and International norm (IEC) to appraise its influency in energy efficiency programs.

O elemento químico neodímio (Nd) atualmente está em evidência pois é parte fundamental em aplicações produzidas por empresas ligadas a tecnologias limpas e de ponta. Porém, é classificado como crítico pelo departamento de energia dos EUA em função do monopólio chinês atuante em sua exploração e comercialização. Devido à crescente demanda frente à restrita disponibilidade, a recuperação deste metal está em ascensão. Uma das aplicações do neodímio é o ímã permanente de neodímio-ferro-boro, utilizado em hard disk drives (HDs) de computadores. Desta forma, este estudo visou caracterizar os ímãs provenientes de HDs de computadores e estabelecer uma rota de recuperação do neodímio por meio de processos mecânicos e hidrometalúrgicos. Por meio da pesagem dos HDs e seus ímãs obteve-se massa média de 3,04 g e 7,91 g para laptop e desktop, respectivamente, representando menos de 3% da massa total do HD. A desmagnetização foi atingida por meio de aquecimento até a temperatura de Curie, em torno de 312 °C, e a cominuição realizada em moinho de facas, onde foram obtidas três granulometrias classificadas em frações A, B e C. Qualitativamente as amostras, foram analisados por meio de difração de raios-X (DRX), onde a fase tetragonal Nd2Fe14B foi o constituinte dominante, e por meio de análise em microscópio eletrônico de varredura (MEV). Semi-quantitativamente os ímãs, seus revestimentos e o precipitado final foram avaliados por meio de espectrometria de fluorescência de raios-X (FRX). A composição média de 21,5% de neodímio e 65,1% de ferro em massa, além de outros elementos químicos, obtida por meio de espectrometria de emissão óptica com plasma (ICP-OES), mostrou teor de neodímio superior aos minérios explorados, tornando este resíduo interessante em relação à recuperação deste metal. O procedimento hidrometalúrgico adotado envolveu a lixiviação das amostras em ácido sulfúrico 2M e a variação de três parâmetros: razão sólido/líquido, temperatura e tempo, em dois níveis. Posteriormente foi realizada a precipitação seletiva por meio de NaOH, formando o duplo sal NaNd(SO4)2.nH2O. Os resultados mostraram que a lixiviação de neodímio atingiu eficiência média acima de 94%, porém todos os experimentos apresentaram material não lixiviado, majoritariamente composto por níquel e cobre. / The chemical element neodymium (Nd) currently is in evidence as it is a fundamental part in applications manufactured by clean and advanced technology companies. However, it is classified as critical by the United States Department of Energy due to Chinese monopoly in its exploration and commercialization. Due to increasing demand in contrast with scarce supply, the recovery of neodymium is growing. One of the applications of this metal is the neodymium-iron-boron permanent magnet, used in hard disk drives (HDDs) of computers. Therefore, this study aimed magnets characterizing from HDDs of computers and then establishing a recovery route for neodymium by mechanical and hydrometallurgical processes. By weighing the HDDs and their magnets it was obtained the average weight of 3.04 g and 7.91 g for laptop and desktop, respectively, representing less than 3% of the HDDs total mass. Demagnetizing was achieved by heating up to Curie temperature of around 312 °C, and the comminution in knives mill resulted in three granulometries classified into fractions A, B and C. Qualitatively, magnets were analyzed by X-ray diffraction (XRD), where the tetragonal phase Nd2Fe14B was the dominant constituent of the sample, and through analysis in a scanning electron microscope (SEM). Semi-quantitatively, the magnets, its covers, and the final precipitate were evaluated by X-ray fluorescence spectrometry (XRF). The average composition of neodymium and iron showed 21.5% and 65.1% by weight, respectively, among other chemical elements. This results were obtained by optical emission spectrometry (ICP-OES), representing a higher neodymium content compared to the ores content, which makes this waste interesting from a neodymium recovery point of view. The procedure adopted involved hydrometallurgical leaching of the samples in 2M sulfuric acid varying three parameters: liquid/solid ratio, temperature and time, each one on two levels. Subsequently, the selective precipitation by NaOH was performed to form the double salt NaNd(SO4)2.nH2O. The results showed that neodymium leaching efficiency reached above 94%, but the experiments showed as well some material left, mainly composed of nickel and copper.

Orientador: Ernesto Ruppert Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-17T07:23:32Z (GMT). No. of bitstreams: 1 OliveiraFilho_MiltonEvangelistade_D.pdf: 4168469 bytes, checksum: 516ef4b8f97c81ba6af204cfc8a05d8c (MD5) Previous issue date: 2010 / Resumo: A presente tese refere-se a um modelo de controle de corrente para conversores em matriz trifásico para trifásico e inversores fonte de tensão trifásica sem capacitor no elo de corrente continua com o objetivo minimizar e compensar as distorções presentes nas tensões de saída dos conversores de modo a obter correntes elétricas senoidais na carga. Nesses conversores, por não possuírem elementos armazenadores de energia de grandes valores, os desequilíbrios e/ou distorções presentes nas tensões de entrada irão se refletir nas tensões de saída. O modelo de controle de corrente proposto consiste em manter constante o módulo do vetor espacial das correntes de saída do conversor em matriz por meio de um regulador PI que altera dinamicamente a razão cíclica de acionamento das chaves de potência compensando os desequilíbrios e distorções das tensões trifásicas de entrada. O desempenho do controle proposto é validado por meio de simulações executadas no Matlab e em resultados experimentais obtidos no protótipo de um inversor fonte de tensão sem capacitor no elo de corrente continua alimentando uma carga RL trifásica / Abstract: This thesis concern a current control method for three-phase matrix converter and three-phase voltage source inverter without a dc link capacitor in order to mitigate and compensate the distortions present in the output voltages so that the output currents are sinosoidal. In these converters, because of lack of large storage elements, imbalances and/or distortions present in the input voltage will be immediately reflected to the converter output voltages. The proposed current control model forces the magnitude of the output space vector current to be constant through a PI controller that dynamically alters the duty cycle of the power converter switching for compensating the imbalances and distortions from input voltages. The performance of this current control is validated by simulations implemented in Matlab and experimental results on the prototype of a voltage source inverter without a DC link capacitor feeding a three-phase RL load / Doutorado / Energia Eletrica / Doutor em Engenharia Elétrica

Now a days, there is lot of alternatives available, which provides green and renewable energy. Through these alternatives, the consumer’s demand for energy is being satisfied. It is important to use the available energy in a systematic and efficient way so that there are many benefits. The purpose of this study is to briefly identify the various prospects, problems, and policies for energy efficiency in industries. Basis of purpose on the negative impacts caused due to the increased use of energy consumption in industries. This literature study is based from practical examples of industries, industrial applications and other new technology. As the electric motor system operates most of the industrial processes, the electricity consumption of motors in industries accounts for two thirds of total energy consumption. Influencing energy efficiency in industries provides substantial advantages. Various motor applications such as pumps, fans, air compressors, cooling compressors, variable speed drives is studied for their operation and working conditions. The utilization of energy efficient technologies to a greater extent can perceive savings to the industries. In spite of being aware of potentials of using energy efficient technologies in industries, energy efficient technologies are not widely used. A barrier to energy efficiency is explained as a practice that inhibits the industrial decision of being efficient in terms of energy and finance. The barriers consent with energy efficiency in industries is fair enough to be considered, while compromising energy for temporary prosperity is not upright. Influence of increased energy efficiency in market areas need coordination of all industries and commercial area throughout the country. The coordination between the industries and commercial sectors can be closely achieved by raising energy policies and energy regulations. The energy efficient policies are considered as cognizance for market transformation and this can maintain the industry, the environment, and the energy. The options available for market transformation are enormous. It is suggested to implement the energy efficient policies as energy efficiency is important for sustainable future. By adopting the right policy, at right situation can provide enormous benefits to the process, industry, and nation. A basis of energy efficiency in industrial application can provide potential energy savings for the present and future industrial situation. This can provide a balance between INDUSTRY-ENVIRONMENT-ENERGY.