Since most of the energy input is converted to thermal energy in laser applications, the proper thermal management of laser systems is an important issue. Maintaining the laser diode and crystal temperature distributions in a narrow range during the operation is the most crucial requirement for the cooling of a laser system. In the present study, thermoelectric cooling (TEC) of a 1064 nm wavelength diode pumped laser source is investigated both experimentally and numerically. During the heat removal process, the thermal resistance through and between the materials, the proper integration of the TEC assembly, and the heat sink efficiency become important. For the aim of evaluating and further improving the system performance, various assembly configurations, highly conductive components, efficient interface materials and heat sink alternatives are considered. Several experiments are conducted during the system development stage, and parallel numerical simulations are performed both for comparison and also for providing valuable input for the system design. Results of the experiments and the simulations agree well with each other. As the laser device works in the transient regime, the experiments and the simulations are also implemented in this regime. In the final part of the study, the experiments are performed under the actual device working conditions. It is proved that with the designed TEC module and the copper heat sink system, the laser device can operate longer than the required operational time successfully.

Orientador: Paulo de Oliveira Camargo / Banca: João Francisco Galera Monico / Banca: Márcio H. O. Aquino / Banca: Inez Staciarini Batista / Banca: Claudio Antonio Brunini / Após a desativação da técnica SA, a ionosfera tornou-se a principal fonte de erro no posicionamento com GPS. O erro associado à ionosfera é diretamente proporcional ao conteúdo total de elétrons (TEC - Total Electron Content) presente ao longo do caminho da trajetória percorrida pelo sinal na ionosfera e inversamente proporcional ao quadrado da freqüência do sinal. O TEC, e conseqüentemente o erro devido à ionosfera, variam no tempo e no espaço e é influenciado por diversas variáveis, tais como: ciclo solar, época do ano, hora do dia, localização geográfica, atividade geomagnética, entre outros. A região brasileira é um dos locais que apresenta os maiores valores e variações espaciais do TEC e onde estão presentes diversas particularidades da ionosfera, tais como, a anomalia equatorial e o efeito da cintilação ionosférica. Desta forma, é importante a realização de pesquisas que visam estudar o comportamento do TEC, e conseqüentemente do erro devido à ionosfera no Brasil, que é um trabalho complexo devido aos diversos fatores que influenciam a variação do TEC, além das particularidades presentes na região brasileira. Estudos desta natureza podem auxiliar a comunidade geodésica brasileira, e demais usuários do GPS, no entendimento das limitações impostas pela ionosfera nas regiões de interesse. Devido à natureza dispersiva da ionosfera, o estudo do comportamento do TEC no Brasil pode ser realizado utilizando os dados GPS de receptores de dupla freqüência pertencentes à RBMC (Rede Brasileira de Monitoramento Contínuo). Adicionalmente, para uma melhor análise, pode-se também utilizar dados das estações da rede IGS (International GNSS Service) da América do Sul. / In the SA absence, the ionosphere is the largest error source in GPS positioning. The error due to the ionosphere in the GPS observables depends on the signal frequency and Total Electron Content (TEC) in the ionospheric layer. The TEC varies regularly in time and space in relation to the sunspot number, the season, the local time, the geographic position, and others. The Brazilian region is one of the regions of the Earth that presents largest values and space variations of the TEC, being influenced by the equatorial anomaly of ionization and ionospheric scintillation. Therefore, it is important to study the TEC behavior in the Brazilian region. Due to the ionosphere dispersive nature, the TEC behavior in Brazil can be studied using GPS data from RBMC (Rede Brasileira de Monitoramento Contínuo - Brazilian Network for Continuous Monitoring of GPS). Additionally, GPS data from IGS (International GNSS Service) network of the South America can also be used in the experiments. / Doutor

Las celdas de combustible de óxido sólido (cuyo acrónimo en inglés es SOFC) son dispositivos energéticos capaces de convertir la energía química de un combustible directamente en energía eléctrica. Esto las dota de unas eficiencias eléctricas muy elevadas, que pueden llegar a ser del 80% si se aprovecha su calor residual de alta calidad mediante turbinas. Además, son capaces de funcionar con una gran variedad de combustibles: hidrógeno, gas natural, gas de síntesis, etanol, metanol, etc. Sin embargo, para su inserción en la cadena de producción energética, su temperatura de funcionamiento debería disminuir al rango de 500-700 ºC sin que se redujeran las densidades de potencias eléctricas generadas. Las SOFC convencionales se basan en la conducción de iones oxígeno de su electrolito, que separa la reacción de combustión del combustible en sus semi-reacciones electroquímicas, generando de este modo la energía eléctrica directamente. Al disminuir la temperatura de operación en este tipo de SOFC, con electrolitos (o membranas) delgados e hidrógeno como combustible, la principal limitación de funcionamiento se centra en la activación y reducción del oxígeno que tiene lugar en el electrodo denominado cátodo. Por otro lado, el empleo de otros combustibles basados en carbono no es compatible con los materiales de ánodos actualmente utilizados. Por tanto, es necesario el desarrollo de nuevos cátodos con mejoradas propiedades electrocatalíticas para la reducción de oxígeno a menores temperaturas, cuyas propiedades termo-mecánicas sean compatibles con las del resto de componentes de la celda, y la obtención de ánodos capaces de funcionar con combustibles basados en carbono. La combinación conjunta de varios lantánidos y bario en la estructura perovskita (LalPrpSmsBab)0.58Sr0.4Fe0.8Co0.2O3 ha permitido obtener compuestos con resistencias de polarización de electrodo significantemente menores que las mostradas por el cátodo del estado de la técnica La0.6Sr0.4Fe0.8Co0.2O3 en el rango de temperaturas 450-650 ºC. / Vert Belenguer, VB. (2011). ELECTRODOS AVANZADOS PARA PILAS DE COMBUSTIBLE DE ÓXIDO SÓLIDO (SOFCs) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/14669 / Palancia

<p dir="ltr">In Global Navigation Satellite Systems Reflectometry (GNSS-R) a critical theme is in un-<br>derstanding and delving into determining specular points, and how to optimize its solutions.<br>The implications are significant for soil moisture, Snow Water Equivalent (SWE), water stor-<br>age, and climate dynamics. For instance, the Signals of Opportunity in P-Band Investigation<br>(SNOOPI) will utilize observations in reference to the specular point to evaluate measurements<br>that could be used to determine water content, soil moisture, and SWE. The focus of this<br>study is presenting and evaluating two prominent methods for determining specular points:<br>the Minimum Path Delay (MPL) and the Unit Difference (UD). Specular point determin-<br>nation presents various challenges which include: surface roughness, temporal and spatial<br>variability, and multipath effects. All of these earth’s surface characteristics pose a challenge<br>for scientists and engineers who wish to collect terrestrial parameters. The analysis in this<br>study offers a comparative approach focusing on data from the simulator for the CubeSat<br>SNOOPI mission is to evaluate specular point determination accuracy as well as offer a real-<br>world application to determine the efficacy of the two methods. Through this evaluation,<br>the researcher aims to improve specular point determination techniques used in the GNSS-R<br>community and offer insights into future techniques and how they can support each other<br>for more precise results.<br></p>

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-04-19T14:22:53Z No. of bitstreams: 1 PDF - Wilson Luiz dos Santos Filho.pdf: 775879 bytes, checksum: 770072135e50de9b9e1f8f021d84d6e2 (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-22T20:25:20Z (GMT) No. of bitstreams: 1 PDF - Wilson Luiz dos Santos Filho.pdf: 775879 bytes, checksum: 770072135e50de9b9e1f8f021d84d6e2 (MD5) / Made available in DSpace on 2016-07-22T20:25:32Z (GMT). No. of bitstreams: 1 PDF - Wilson Luiz dos Santos Filho.pdf: 775879 bytes, checksum: 770072135e50de9b9e1f8f021d84d6e2 (MD5) Previous issue date: 2014-11-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / From the analysis of Financial Mathematics teaching in Brazil and the confirmation that the majority of the Brazilian population deals, in an inefficient way, with financial tran- sactions, we proposed in this work a strategy to approach a kind of Financial Mathematics capable of turning this theme much more meaningful to High School Students. We recal- led the basic concepts of Financial Mathematics, went through the Financial Education in Brazil, discussed the main Amortization Systems practiced in our country with day-by-day examples and, finally, we presented an interesting application in the calculation of car loans, describing the characteristics of Leasing and Personal Credit (CDC). Besides that, we eli- cited the calculations of Total Effective Cost (CET) of a transaction, applying the use of a Financial Calculator. / A partir da análise acerca do ensino da Matemática Financeira no Brasil e da consta- tação de que grande parte do povo brasileiro lida de forma ineficiente com transações finan- ceiras, propusemos neste trabalho, uma estratégia de abordagem da Matemática Financeira capaz de tornar mais significativo aos alunos do Ensino Médio este tema. Recordamos os conceitos básicos daMatemática Financeira, passeamos pela Educação Financeira no Brasil, discutimos os principais Sistemas de Amortização praticados em nosso país com exemplos corriqueiros e, finalmente, apresentamos uma aplicação interessante no cálculo de um finan- ciamento de veículo, descrevendo as características Leasing e CDC, além de evidenciarmos o cálculo do Custo Efetivo Total (CET) de uma transação, recorrendo ao uso de uma Calcu- ladora Financeira.

Ces travaux de recherche doctorale s'inscrivent dans le domaine de l'Interaction Homme-Machine (IHM) en informatique ambiante avec, comme sujet d'étude, le couplage de ressources d'interaction. Coupler deux ressources, c'est l'action de les lier de manière à ce qu'elles opèrent conjointement pour fournir de nouveaux services. En réponse au foisonnement d'exemples et de techniques d'interaction ad hoc, cette étude propose une définition formelle de la notion de couplage, un cadre analytique ainsi qu'un intergiciel pour l'expérimentation. Le cadre d'analyse inclut d'une part, une taxonomie qui permet de comprendre l'espace problème et d'identifier des pistes de recherche encore inexplorées, et d'autre part des outils formels couvrant le cycle de vie d'un couplage, la composition de couplages, et les techniques d'interaction pour que l'utilisateur puisse façonner son espace interactif par le biais de couplages.

New technologies, more specifically, Information and Communication Technologies (ICTs), are today indispensable in all professions. It is undeniable, however, that some professions have been affected to a greater extent than others. This study describes ICTs used in conference interpreting, in both professional and educational settings. It also records the interpreters' and interpreter trainers' perceptions of ICTs, especially in terms of improving the quality of their performance and their professionalism. The data has been collected through two global surveys, both conducted mainly through questionnaires and personal interviews, and triangulated with in situ observations. As to the results of the research, it was found that variation in use was not always due to generational or regional differences as had been expected. Conference interpreter trainers, on their part, are identifying different ways to overcome budgetary restrictions to allow students to learn about ICTs in order to better prepare them for the labor market. / Las nuevas tecnologías, especialmente las Tecnologías de la Información y la Comunicación (TICs), son actualmente un componente indispensable de todas las profesiones. Sin embargo, es innegable que hay profesiones que han resultado más beneficiadas por las TICs que otras. La presente investigación describe las TICs utilizadas en la interpretación de conferencias, tanto en el ámbito profesional como en el formativo. Registra asimismo la percepción y actitud de los intérpretes y de los formadores de intérpretes de conferencia hacia las TICs, en cuanto a mejorar la calidad de su desempeño y su profesionalismo. Para recoger la información, se llevaron a cabo dos encuestas a nivel global por medio de cuestionarios, complementadas con una serie de entrevistas y observaciones.En cuanto a los resultados de la investigación, se encontró que la variación en el uso no era siempre resultado de diferencias generacionales o regionales. Los formadores de intérpretes de conferencia, por su parte, están encontrando nuevas formas de superar las restricciones presupuestales para que sus estudiantes aprendan sobre el uso de las TICs, con el objeto de prepararlos mejor para su inserción en el mercado laboral.

In Turkey, most of the existing buildings have been designed according to Turkish Earthquake codes of 1975 and 1997. It is a well known fact that, poor material quality, poor design, poor control on site and inadequate workmanship makes existing buildings vulnerable to earthquake. In addition, change in function of buildings becomes another problem. These problems increase the importance of assessment of existing buildings. For this purpose, a new chapter has been added to the new code and assessment methods of existing buildings is regulated. 2007 Turkish Earthquake Code offered two analysis methods, linear and nonlinear analysis methods. Due to comprehensive computational, modeling and assessment challenges involved in applying the code procedures that are generally not well understood by practicing engineers, the use of commercial package computer programs is preferred. There are widely used three software&rsquo / s in Turkey / Idestatik, Sta4 and Probina. These programs currently handle linear assessment method only. This study aims to compare the assessment results of the most widely used three structural analysis and design softwares in Turkey. For this purpose, four v different structures having different property and plan were employed. These buildings were selected to be representative of the mostly common building types. Each building has been modeled and identified with the same material properties, the same reinforcement details and the same geometric properties in each software. The results of the assessment are compared in order to determine the inconsistencies among the software&rsquo / s and their reliability.

Nous étudions l'effet thermo-électrique et les phénomènes qui en résultent, forces et les courants thermoélectriques (TEC) sous l'action d'un champ magnétique externe imposé lors de la solidification d'alliages métalliques. Nous avons utilisé des simulations numériques, des observations directes et des examens de laboratoire. L'interaction entre les courants thermo-électriques et le champ magnétique externe lors de la solidification se produit des forces électromagnétiques et donc un écoulement du métal liquide. Le résultat est nommé effet magnétique thermoélectrique (TEME). Les formulations de TEC, les forces et les équations gouvernant les écoulements TEM sont donnés. Afin de mieux prouver l'existence de la TEME, des expériences par méthode d'imagerie à rayons X menées au synchrtron ont été utilisées pour observer in-situ et en temps réel l'action directe des forces et les mouvements TEM pendant la solidification directionnelle des alliages Al-Cu. Nous avons montré la cohérence raisonnable entre les calculs analytiques et des simulations numériques qui ont exécuté avec les mêmes conditions de traitement. En outre, la capacité des écoulements thermo-électriques à influer sur la microstructure lors de la solidification directionnelle sont expérimentalement évaluées dans les autres cas en réalité. La solidification directionnelle d'une seule phase de formation des alliages Al-Cu sous divers champs magnétiques montre que les écoulements TEM sont capables de modifier la forme de l'interface liquide-solide conduisant à des morphologies différentes. L'effet le plus intense se produit dans différents champs magnétiques pour différentes morphologies, en effet, le champ magnétique élevé est nécessaire pour la morphologie a une plus petite longueur typique. Ceci est en accord avec le comportement des vitesses de TEM qui varient avec les champs magnétiques imposés ainsi que les différentes échelles de longueur typique. Cette variation est confirmée par des simulations numériques 3D. Nous montrons que les dendrites primaires et à l'avant de la phase eutectique, peuvent être modifiés par les mouvements TEM et les forces de TEM dans le solide pour améliorer la croissance de la phase de Al2Cu facettes primaire pendant la solidification des Al-40wt%Cu hypereutectiques. Le mécanisme de renforcement de la croissance de la phase facettes Al2Cu est confirmé par la transmission électronique observation au microscope, et la raison de la formation de la structure de croissance de couple de Al-26wt% Cu alliages est vérifiée par le test de l'analyse thermique différentielle. Ainsi, nous pouvons affirmer que le champ magnétique élevé facilite la formation de la structure de la croissance de couple pour hypoeutectiques alliages Al-Cu, et favorise la croissance de la phase Al2Cu primaire pour hypereutectiques Al-Cu alliages. / We have investigated the thermoelectric magnetic (TEM) forces and flows resulting from the interaction between the internal thermoelectric currents (TEC) and the imposed external magnetic field during solidification. Numerical simulations, direct observations and experimental examinations were undertaken. As the natural phenomenon, TEC was discovered almost 200 years ago, therefore, our introduction begins from then on. It is shown that the interaction between TEC and external magnetic field during solidification in the cont put forth new interesting phenomena in the context of a rising field named Electromagnetic Processing of Materials. After that, it is discussed how the TEC appear and the TEM effect (TEME, referring to both TEM forces and flows) behaves at the liquid-solid interface in directional solidification under external magnetic field. Meanwhile, formulations of TEC, TEM forces and flows are given, and numerical simulations of TEME are performed to visually display the TEM forces and flows. In order to further prove the existence of TEME, in situ synchrotron X-ray imaging method was used to observe the direct resultant of TEM forces and flows during directionally solidifying the Al-Cu alloys. The observations show reasonable consistency with the analytical calculations and numerical simulations performed with the same process conditions. Except confirmation the existence of TEME, its abilities to affect the microstructure during directional solidification are experimentally investigated in the more realistic cases. The single phase forming Al-Cu alloys are directionally solidified under various magnetic fields, which shows that TEM flows are capable to modify the shape of liquid-solid interface, and the most intensive affect occurs under different magnetic fields for different interface morphologies. Indeed, the smaller the typical length of the morphology is the higher the magnetic field is needed. This agrees with the estimating regulation of the velocity of TEM flows changing with magnetic fields for different typical length scales, and is confirmed by 3D numerical simulations. Directional solidification of multiphase forming Al-Cu alloys under various magnetic fields shows that the mushy zone length (distance between the front of primary dendrites and eutectic phases) varies with the magnetic fields, which can be attributed to the redistribution of rejected solutes by TEM flows. In addition, apparent enhanced growth of the primary faceted Al2Cu phase is founded when Al-40wt%Cu alloys are solidified under sufficient high magnetic fields, this should be ascribed to the TEM forces acting on the solid because strains are able to lead the formation of defects and thus benefit to the growth of faceted phase. This is confirmed by comparison of the dislocations in samples solidified without and with a 10T magnetic field via transmission electron microscopy observation. In another aspect, an almost entire couple growth structure is achieved when Al-26wt%Cu alloys are directionally solidified under a 4T magnetic field, which can be explained by the effect of high magnetic field on changing the nucleation temperature and growth velocity of each phase. Moreover, the differential thermal analysis test on the nucleation temperature of both α-Al and eutectic phases verified this explanation. Therefore, we conclude that high magnetic field facilitates the formation of couple growth structure for hypoeutectic Al-Cu alloys, reversely, enhances the growth of primary dendrite for hypereutectic Al-Cu alloys.

Nous étudions l'effet thermo-électrique et les phénomènes qui en résultent, forces et les courants thermoélectriques (TEC) sous l'action d'un champ magnétique externe imposé lors de la solidification d'alliages métalliques. Nous avons utilisé des simulations numériques, des observations directes et des examens de laboratoire. L'interaction entre les courants thermo-électriques et le champ magnétique externe lors de la solidification se produit des forces électromagnétiques et donc un écoulement du métal liquide. Le résultat est nommé effet magnétique thermoélectrique (TEME). Les formulations de TEC, les forces et les équations gouvernant les écoulements TEM sont donnés. Afin de mieux prouver l'existence de la TEME, des expériences par méthode d'imagerie à rayons X menées au synchrtron ont été utilisées pour observer in-situ et en temps réel l'action directe des forces et les mouvements TEM pendant la solidification directionnelle des alliages Al-Cu. Nous avons montré la cohérence raisonnable entre les calculs analytiques et des simulations numériques qui ont exécuté avec les mêmes conditions de traitement. En outre, la capacité des écoulements thermo-électriques à influer sur la microstructure lors de la solidification directionnelle sont expérimentalement évaluées dans les autres cas en réalité. La solidification directionnelle d'une seule phase de formation des alliages Al-Cu sous divers champs magnétiques montre que les écoulements TEM sont capables de modifier la forme de l'interface liquide-solide conduisant à des morphologies différentes. L'effet le plus intense se produit dans différents champs magnétiques pour différentes morphologies, en effet, le champ magnétique élevé est nécessaire pour la morphologie a une plus petite longueur typique. Ceci est en accord avec le comportement des vitesses de TEM qui varient avec les champs magnétiques imposés ainsi que les différentes échelles de longueur typique. Cette variation est confirmée par des simulations numériques 3D. Nous montrons que les dendrites primaires et à l'avant de la phase eutectique, peuvent être modifiés par les mouvements TEM et les forces de TEM dans le solide pour améliorer la croissance de la phase de Al2Cu facettes primaire pendant la solidification des Al-40wt%Cu hypereutectiques. Le mécanisme de renforcement de la croissance de la phase facettes Al2Cu est confirmé par la transmission électronique observation au microscope, et la raison de la formation de la structure de croissance de couple de Al-26wt% Cu alliages est vérifiée par le test de l'analyse thermique différentielle. Ainsi, nous pouvons affirmer que le champ magnétique élevé facilite la formation de la structure de la croissance de couple pour hypoeutectiques alliages Al-Cu, et favorise la croissance de la phase Al2Cu primaire pour hypereutectiques Al-Cu alliages.