In this thesis a theoretical background of Nd:YAG lasers has been presented and key parameters of a design have been stated. Both pulsed mode and CW mode designs have been made / a 500mJ xenon flash lamp has been investigated as the pulsed light source and a 500W tungsten halogen lamp has been used as the continuous light source for optical pumping. Closed cooling system has been constructed. De-ionized water has been used as coolant. The goal has been acomplished by constructing a CW mode prototype. The output power has been calculated. Dependence of output power to the reflectivity of output coupler is simulated and optimum reflectivity is calculated. Theoretical emission bands of Nd:YAG have been observed experimentally.

Frequency modulated continuous wave (FM-CW) radar altimeters are used in civil and military applications. Proximity fuses, automatic cruise control systems of cars, radar altimeter of planes are examples to these applications. The goal of this thesis is to present a method for altitude determination using an FM-CW radar. For this purpose principles of radars and FM-CW systems are studied and related subjects are inspected. After this inspection, algorithms for altitude determination are evaluated. Consequently signal detection and processing methods are proposed to build an altitude determining algorithm. Also an analytical test environment for altitudes between 100 m and 4000 m is developed in computer as a result of researches. Test environment simulated the performance of altitude determining algorithm and FM-CW Radar Altimeter. The hardware is designed and implemented accordingly.

Universiẗat, Diss., 2002--Marburg.

Made available in DSpace on 2014-06-11T19:26:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-03-20Bitstream added on 2014-06-13T18:47:49Z : No. of bitstreams: 1 meneguesso_e_me_sjrp.pdf: 1062856 bytes, checksum: bda0bf2d8904199e8ddf38065e4a5410 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo principal deste trabalho é mostrar a existência dos complexos de Eilenberg-MacLane, ou K(G, n)-espaços (como são comumente chamados), para G um grupo arbitrþario se n = 1, e G abeliano, se n = 2. Esses espaicos desempenham um papel muito importante na Topologia Algébrica, principalmente na conexão entre homotopia e (co)homologia / The main purpose of this work is to show the existence of the Eilenberg- Maclaneþs complexes, or K(G, n)-spaces (as they are usually called), for an arbitrary group G if n = 1, and G abelian, if n = 2. Such spaces play a very important role in Algebraic Topology, mainly in the connection between homotopy and (co)homology.

Made available in DSpace on 2016-06-02T20:09:20Z (GMT). No. of bitstreams: 1 5883.pdf: 4918848 bytes, checksum: be74a4a1c85de8e4a97d1f9e3deff58f (MD5) Previous issue date: 2014-02-25 / Financiadora de Estudos e Projetos / The civil construction is responsible for generating a lot of waste and the lack suitable for waste treatment can cause many environmental and social problems. Brazil is the world s largest producer in the sugar and alcohol sector. During the processing of sugarcane is generated the ash sand of the sugarcane bagasse (ASSB), resulting from the burning of bagasse in boilers. The ASSB is usually released in the environment inappropriately. This study aimed to verify the possibility of using the ASSB to partially replace river sand and the construction waste (CW) to partially replace crushed stone in concretes. The ASSB samples were standardized by manual sieving and deagglomeration. The CW samples were standardized by manual screening and automated screening. The ASSB and CW were subjected to physical and chemical characterization, by its chemical composition, sieve analysis, powdery material, absorption, bulk density and true density. The ASSB was used in concretes with 30% substitute level and the CW was used with 30%, 50% and 100% substitution levels, it were produced seven concretes recipe (REF, 30ASSB, 30CW, 50CW, 30ASSB30CW, 30ASSB50CW and 100CW). The concretes were submitted to tests of compressive and tensile strength, elastic modulus, void index, absorption, density and carbonation. The concretes produced with the isolated use of 30 % of ASSB (30ASSB) and 30 % and 50 % of CW (30CW and 50CW) presented similar mechanical properties to the reference concrete. The concretes produced with 30% of ASSB and 30% and 50 % of CW ( 30ASSB30CW, 30ASSB50CW) presented similar progression of carbonation to the reference concrete, however, the combined use of the ASSB and CW resulted in the achievement of concrete with a reduction of 17%, 12% and 8% in compressive strength at 7, 28 and 91 days, respectively. Thus it is possible to indicate the combined use of the ASSB and the CW as a partial substitute natural aggregates in concrete, since the decrease in resistance can be considered low against the possibilities of using concrete containing these wastes. / A construção civil é responsável por gerar uma grande quantidade de resíduos, sendo que a falta de tratamento adequado para tais resíduos pode ocasionar diversos problemas ambientais e sociais. O Brasil é o maior produtor mundial no complexo sucroalcooleiro. Durante o processamento da cana-de-açúcar gera-se a areia de cinza do bagaço da cana-de-açúcar (ACBC), resultante da queima do bagaço em caldeiras. Essas, geralmente são lançadas ao meio ambiente de forma inadequada. Essa pesquisa objetivou verificar a possibilidade do uso da ACBC e do resíduo da construção civil (RCC) em concretos, sendo que a ACBC foi utilizada como substituta parcial do agregado miúdo natural e o RCC como substituto parcial do agregado graúdo natural. As amostras de ACBC foram padronizadas através de peneiramento manual e desaglomeração das partículas. As amostras de RCC foram padronizadas por meio de triagem manual e peneiramento mecanizado. A ACBC e o RCC foram caracterizados quanto à composição granulométrica, absorção, massa específica, massa unitária e propriedades químicas. Após a caracterização, foi realizada a dosagem e moldagem de corpos de prova de concreto com teores de substituição de 30% de ACBC e 30%, 50% e 100% de RCC e foram produzidos sete traços (REF, 30ACBC, 30RCC, 50RCC, 30ACBC30RCC, 30ACBC50RCC e 100RCC). Foram realizados ensaios de resistência à compressão, resistência à tração, módulo de elasticidade, índice de vazios, absorção, massa específica e carbonatação. Os concretos produzidos com a utilização isolada de 30% de ACBC (traço 30ACBC) e de 30% e 50% de RCC (traços 30RCC e 50RCC) apresentaram propriedades mecânicas similares ao do concreto referência (REF). Os concretos produzidos com 30% de ACBC em conjunto com 30% e 50% de RCC (traços 30ACBC30RCC, 30ACBC50RCC) apresentaram evolução na frente de carbonatação similar ao concreto referência, porém, a utilização conjunta da ACBC e do RCC resultou na obtenção de concretos com redução de 17%, 12% e 8% na resistência à compressão aos 7, 28 e 91 dias, respectivamente. Desse modo é possível indicar o uso conjunto da ACBC e do RCC como substitutos parciais de agregados naturais em concretos, pois a redução da resistência pode ser considerada baixa frente às possibilidades de utilização dos concretos contendo esses resíduos.

Fundação de Amparo a Pesquisa do Estado de Minas Gerais / The phenomenon of cavitation on the metal surface causes erosion decaying components in operation, in particular the blades of turbines for power generation, accounting for maintenance costs and losses in electricity generation resulting from periodic stops. The blades of these turbines, particularly those manufactured by C-Mn steel (carbon - manganese) are coated by arc welding for stainless steel protective order to present more uptime or longer intervals between maintenance periods. Among the materials used to coat these blades are austenitic stainless steels, and stainless steels featured in the Co and Cobased alloys (commercially Stellites). However, the latter have a high cost. Among the welding processes applied to the coating, the technique of adding cold wire (GMAW and GMAW-CW-AF) is presented as an advantageous tender in relation to other techniques currently existing special and conventional welding. Given the context, this work seeks to study, apply and evaluate the effect of alloy and austenitic stainless steel alloys Co (CoCrMo and CoCrW) deposited by GMAW-CW for the purpose of characterization, comparison, formulation and deposition of new alloys from commercial wire correlating with resistance to mass loss. The adjustments of welding technique have focused on obtaining the manufacture of coatings suitable welding parameters. The cavitation wear resistance was evaluated according to ASTM G 32, correlating microstructure and phases by optical microscopy, SEM-EDS, chemical composition and optical emission spectrometry analyzes of the phases present by XRD. The qualities of the welded surfaces have been analyzed by visual examination and Penetrant Liguid according to standard NT (Nondestructive Testing). It was found that the coatings showed good weldability without discontinuities or defects with good surface finish. In the analysis of the coatings of cobalt, the alloy H (Stellite electrode 21 and 309LSi as cold wire) and M (Stellite 6 and 309LSi electrode as cold wire) showed good performance in resistance to cavitation in similar levels of surface roughness and hardness when compared to coatings Stellites 21 and 06, made by conventional GMAW process. / O fenômeno da cavitação sobre a superfície metálica provoca à erosão que deteriora componentes em operação, em particular as pás de turbinas hidráulicas de geração de energia, sendo responsável por custos da manutenção e perdas em geração de energia elétrica decorrente das paradas periódicas. As pás dessas turbinas, em especial as fabricadas pelo aço C-Mn (carbono manganês) são revestidas por soldagem a arco por aços inoxidáveis a fim de proteção para que apresentem maior tempo de operação ou maior intervalo entre os períodos de manutenção. Entre os materiais aplicados para revestir essas pás estão os aços inoxidáveis austeníticos, e em destaque os aços inoxidáveis ao Co e as ligas à base de Co (comercialmente Stellites). No entanto, estes últimos apresentam alto custo. Entre os processos de soldagem aplicados para o revestimento, a técnica de adição de arame frio (GMAW-CW ou GMAW-AF) se apresenta como uma proposta vantajosa em relação às outras técnicas especiais de soldagem existentes atualmente e convencionais. Diante do contexto, este trabalho buscou estudar, aplicar e avaliar o efeito das ligas de aço inoxidáveis austeniticos e ligas de Co (CoCrMo e CoCrW) depositadas pelo processo GMAW-CW com a finalidade de caracterização, comparação, formulação e deposição de novas ligas a partir de arame comerciais, relacionando com a resistência à perda de massa. As adequações da técnica de soldagem têm como foco a obtenção dos parâmetros de soldagem adequados à confecção dos revestimentos. A resistência ao desgaste por cavitação foi avaliada segundo a Norma ASTM G 32, correlacionando com a microestrutura e fases por microscopia óptica, MEV-EDS, composição química por espectrometria de emissão óptica e análises das fases presentes por DRX. As qualidades das superfícies soldadas foram analisadas por análise visual e Líquido Penetrante de acordo com a norma de END (Ensaio Não Destrutivo). Verificou-se que os revestimentos apresentaram boa soldabilidade, sem descontinuidades ou defeitos, com bom acabamento superficial. Na análise dos revestimentos de cobalto, as ligas H (eletrodo Stellite 21 e 309LSi como arame frio) e M (eletrodo Stellite 6 e 309LSi como arame frio) apresentaram bom desempenho de resistência a cavitação em semelhantes níveis de rugosidade e dureza quando comparados aos revestimentos de Stellites 21 e 6, feitos pelo processo GMAW convencional. / Doutor em Engenharia Mecânica

No description available.

In this work, we studied three proteins from three different organisms by EPR spectroscopy: NpHtrII is part of the phototaxis system found in halophilic archaea, ChR2 is a cation-selective channel isolated from a green alga, and HsaCCA is an enzyme involved in the protein biosynthesis of humans. The goal was to identify characteristic conformations and dynamics in each of the studied proteins that were linked to their specific functions. The scientific disciplines employed in this work include biochemistry (site-directed spin-labeling), bioinformatics (data analysis, molecular modeling), informatics (device control, software development), molecular biology (mutagenesis, transformation, heterologous protein expression, protein purification, protein characterization), and physics (EPR spectroscopy, optical spectroscopy, experimental assembly). The experimental results show a strong interdependence between protein structure, conformers, dynamics, and function. Hydrogen bonds, although being a transient electrostatic attraction between polar molecules, are the key molecular interactions required for the conservation of protein functionality: Hydrogen bond networks in NpSRII and ChR2 stabilize the helix bundles, and hydrogen bond networks in HsaCCA mediate interdomain flexibility. However, the resulting structural alterations observed in our proteins manifest on a much larger scale: We have detected changes in the protein backbone mobility of the HAMP2 domain in NpHtrII after signaling. We have discovered the TMH B movement in ChR2 accompanying channel opening. And we have documented a substrate-dependent motion of the head domain in HsaCCA during catalysis.

No description available.

Space-borne radar interferometry provides a global vantage point to understand climate change, global weather phenomenon, and other Earth dynamics. For climate change observations, space-borne interferometers can be utilized to relate ocean topography to temperature, thus providing a global map of ocean temperatures. Since the oceans are in constant motion, a single-pass interferometer is needed to successfully make these measurements of ocean height. The feasibility of a single-pass measurement is dependent on the physical size of the instrument, hence it is cheaper and more practical to launch a small, light weight instrument into space. Since instrument size scales inversely with operating frequency, high frequency microwave technology (Ku-band and Ka-band) is preferred for these types of applications. However, space-borne deployments become more difficult to implement at these frequencies since the physical structure of the instrument changes in the harsh environment of space. For that reason, a ground-based Ku-band (13.245GHz) radar interferometer has been developed at the University of Massachusetts, Amherst Microwave Remote Sensing Laboratory (MIRSL). In this thesis, a description of the radar hardware as well as interferometric results from Mount Sugarloaf provide a measure of the performance of the radar and demonstrate the capabilities of using a ground-based interferometer as a test-bed for space-borne applications.