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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

A influ?ncia do agregado gra?do na resist?ncia mec?nica e propriedades de fratura de um concreto para pavimenta??o r?gida

Paiva, Danyel Fl?vio Lopes de 25 November 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-22T18:37:40Z No. of bitstreams: 1 DanyelFlavioLopesDePaiva_DISSERT.pdf: 2519156 bytes, checksum: b31565236fd0ac524181f84e8d976787 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-03-03T23:45:00Z (GMT) No. of bitstreams: 1 DanyelFlavioLopesDePaiva_DISSERT.pdf: 2519156 bytes, checksum: b31565236fd0ac524181f84e8d976787 (MD5) / Made available in DSpace on 2017-03-03T23:45:00Z (GMT). No. of bitstreams: 1 DanyelFlavioLopesDePaiva_DISSERT.pdf: 2519156 bytes, checksum: b31565236fd0ac524181f84e8d976787 (MD5) Previous issue date: 2016-11-25 / Este trabalho tem como objetivo analisar a influ?ncia do agregado gra?do na resist?ncia mec?nica e propriedades de fratura de um concreto destinado a pavimenta??o r?gida, utilizado nas obras de duplica??o e adequa??o de capacidade da BR-101/RN, corredor Nordeste, entre os munic?pios de Parnamirim/RN e Ar?s/RN. Em primeira an?lise, foi variado o teor do agregado gra?do no tra?o de refer?ncia, onde o percentual de agregado gra?do em fun??o da quantidade total dos agregados foi de 59% a 69%. Para a segunda an?lise foi reproduzido o tra?o de refer?ncia apenas com agregados de di?metros m?ximos 12,5 mm, 19 mm e 25 mm. Para ambas as an?lises foram feitos ensaio de resist?ncia ? compress?o axial, tra??o na flex?o e na compress?o diametral, m?dulo de elasticidade, tenacidade ? fratura e energia de fratura. Os resultados da an?lise da influ?ncia do teor mostraram que o tra?o com menor teor de agregado gra?do - T (59%) apresentou maiores resist?ncias mec?nicas em rela??o ao tra?o de refer?ncia - REF (64%), com aumentos de 8% para a resist?ncia ? compress?o e tra??o na flex?o, enquanto sua tenacidade ? fratura e energia de fratura diminu?ram em 7% e 12%, respetivamente. J? o tra?o com maior teor de agregado - T (69%), apresentou diminui??o na resist?ncia mec?nica em 12% para resist?ncia ? compress?o e tra??o na flex?o, por?m aumento de tenacidade ? fratura e energia de fratura de 4% e 2%, respectivamente. J? os resultados da an?lise da influ?ncia do di?metro m?ximo do agregado gra?do, mostraram que a diminui??o do di?metro m?ximo do agregado causou aumento da resist?ncia mec?nica e diminui??o dos par?metros de fratura. O tra?o VAR. 12, apresentou aumentos em rela??o ao tra?o de refer?ncia (REF) de 12% para a resist?ncia ? compress?o axial e 19% para a resist?ncia ? tra??o na flex?o, por?m com redu??es de 38% para a tenacidade a fratura e 22% para a energia de fratura. Os maiores resultados dos par?metros de fratura nesta an?lise foram apresentados pelo tra?o de refer?ncia ? REF, por?m com diferen?a considerada insignificante em rela??o ao tra?o VAR. 25. / This study aims to analyze the influence of the large aggregate on the mechanical strength and fracture properties of a concrete headed for rigid paving, used in the constructions of duplication and capacity adaptation of the BR-101 / RN, Northeast corridor, between cities from Parnamirim / RN and Ar?s /RN. In the first analysis, the content of the aggregate was varied in the reference tract, in which the percentage of large aggregate as a function of the total amount of the aggregates was from 59% to 69%. For the second analysis, the reference trace was reproduced only with aggregates with maximum diameters, such as 12.5 mm, 19 mm and 25 mm. For both analyzes, axial compression, flexural tensile and diametral compression, modulus of elasticity, fracture toughness and fracture energy were tested. The results of the analysis of the contente influence showed that the trait with lower content of large aggregate ? T (59%) presented higher mechanical resistance in relation to the reference trait ? REF (64%), with increases of 8% for resistance to compression and tensile strength in flexion, while its fracture toughness and fracture energy decreased by 7% and 12%, respectively. On the other hand, the trait with higher T - aggregate content (69%) showed a decrease in mechanical strength of 12% for compression strength and flexural tensile strength, but an increase of fracture toughness and fracture energy of 4% and 2%, respectively. With regard to the results of the influence analysis of the maximum diameter of the large aggregate showed that the reduction of the maximum diameter of the aggregate caused an increase in the mechanical resistance and decrease of the fracture parameters. The VAR - 12 trait presented increases with respect to the reference trajectory (REF) by 12% for the axial compressive strength and 19% for tensile strength in the flexure, but with reductions of 38% for fracture toughness and 22% for energy of fracture. The greatest results of the fracture parameters in this analysis were presented by the REF- reference trait , but with a difference considered insignificant in relation to the VAR- 25 trait.
112

Desenvolvimento de FSS mecanicamente reconfigur?vel para aplica??es em micro-ondas

Carvalho, Rafaela Gomes Gon?alves de 30 January 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-07-03T12:46:24Z No. of bitstreams: 1 RafaelaGomesGoncalvesDeCarvalho_DISSERT.pdf: 3495415 bytes, checksum: 8f2ba59f5497dd2972e751f7feaa758f (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-07-06T15:18:49Z (GMT) No. of bitstreams: 1 RafaelaGomesGoncalvesDeCarvalho_DISSERT.pdf: 3495415 bytes, checksum: 8f2ba59f5497dd2972e751f7feaa758f (MD5) / Made available in DSpace on 2017-07-06T15:18:49Z (GMT). No. of bitstreams: 1 RafaelaGomesGoncalvesDeCarvalho_DISSERT.pdf: 3495415 bytes, checksum: 8f2ba59f5497dd2972e751f7feaa758f (MD5) Previous issue date: 2017-01-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A reconfigurabilidade ? uma caracter?stica muito importante nos sistemas modernos de comunica??o, pois permite que uma mesma estrutura se adapte aos diferentes cen?rios de uma mesma aplica??o, como por exemplo, radomes, r?dio cognitivo, e telas adaptativas que bloqueiam transmiss?es sem fio indesejadas. Essa caracter?stica pode ser alcan?ada mediante m?todos tradicionais, como o uso de dispositivos semicondutores ativos (diodos PIN, Schottky) ou capacitores vari?veis acoplados a cada elemento b?sico da superf?cie seletiva de frequ?ncia (FSS), sendo necess?rio o uso de um circuito separado para alimentar esses dispositivos. No entanto, estes m?todos requerem um n?mero elevado de elementos ativos, o que aumenta a complexidade e o custo de fabrica??o, abrindo espa?o para o surgimento de t?cnicas mais simples e robustas quanto ? seletividade, como a reconfigurabilidade mec?nica. Este trabalho consiste no desenvolvimento de uma superf?cie seletiva de frequ?ncia (FSS) reconfigur?vel, para operar na banda X, formada por patches condutores triangulares impressos em uma camada de diel?trico de fibra de vidro (FR-4). A FSS desenvolvida permite a reconfigura??o da frequ?ncia de resson?ncia a partir da varia??o do ?ngulo da onda incidente na estrutura, com polariza??o TE, e pode ser aplicada em sistemas de comunica??o via sat?lite a partir de uma interface microcontrolada. A an?lise da estrutura da FSS ? efetuada atrav?s do software Ansoft Designer do M?todo das Ondas ? WCIP. / Reconfigurability is a very important feature in modern communication systems because it allows the same structure to adapt to different scenarios of the same application, such as radomes, cognitive radio, and adaptive screens that block unwanted wireless transmissions. This characteristic can be achieved by traditional methods, such as the use of active semiconductor devices (PIN and Schottky diodes) or variable capacitors coupled to each basic element of the frequency selective surface (FSS), requiring the use of a separate circuit to feed these components. However, these methods require a high number of active elements, which increases the complexity and cost of manufacturing, opening space for the emergence of simpler and more robust techniques for selectivity, such as mechanical reconfigurability. This work consists of the development of a reconfigurable frequency selective surface (FSS), to operate in the X-band, composed of triangular patch elements printed on a dielectric layer of fiberglass (FR-4). The developed FSS allows the reconfiguration of the resonant frequency from the variation of the angle of the incident wave in the structure, in the TE polarization, and can be applied in satellite communication systems through a microcontrolled interface. The analysis of the structure of the FSS is done through Ansoft Designer software and WCIP method.
113

Desenvolvimento de uma estrat?gia de controle para uma unidade de bombeio inteligente

Oliva, Gabriel Bessa de Freitas Fuezi 05 July 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-11-03T20:19:53Z No. of bitstreams: 1 GabrielBessaDeFreitasFueziOliva_DISSERT.pdf: 6203013 bytes, checksum: 7504f427f888a49303ef36d8aab5a72d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-11-16T22:15:44Z (GMT) No. of bitstreams: 1 GabrielBessaDeFreitasFueziOliva_DISSERT.pdf: 6203013 bytes, checksum: 7504f427f888a49303ef36d8aab5a72d (MD5) / Made available in DSpace on 2017-11-16T22:15:44Z (GMT). No. of bitstreams: 1 GabrielBessaDeFreitasFueziOliva_DISSERT.pdf: 6203013 bytes, checksum: 7504f427f888a49303ef36d8aab5a72d (MD5) Previous issue date: 2017-07-05 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O m?todo de eleva??o artificial por Bombeio Mec?nico (BM) ? o mais utilizado nos po?os de petr?leo no Brasil e no mundo. Este m?todo se destaca pela sua simplicidade, baixo custo em investimentos e manuten??es, flexibilidade quanto ? vaz?o de opera??o e possibilidade de operar com fluidos de diferentes composi??es e viscosidades. No entanto, as unidades de bombeio mec?nico (UB?s), assim como todo equipamento mec?nico, necessitam de manuten??es peri?dicas sejam elas corretivas ou preventivas. Dentre as atividades operacionais mais comuns realizadas nas unidades de bombeio destacam-se o balanceamento e o ajuste do curso da haste polida. A realiza??o dessas atividades requer a parada da produ??o do po?o e ? feita manualmente por uma equipe que ? deslocada at? o local onde se encontra a UB. Nesse contexto, a Petrobras em parceria com a UFRN e fornecedores desenvolveram uma unidade de bombeio mec?nico, denominada Unidade de Bombeio Inteligente (UBI), capaz de realizar o balanceamento e o ajuste do curso da haste polida sem a necessidade de uma equipe se deslocar at? a UB. Isto posto, beneficiando-se das vantagens da UBI, este trabalho se prop?e a desenvolver uma estrat?gia para controlar automaticamente a Unidade de Bombeio Inteligente. O desenvolvimento dessa estrat?gia tem por objetivo garantir que o equipamento tanto opere em condi??es adequadas e dentro de seus limites de seguran?a (previamente definidos pelo operador), quanto otimize a produ??o do po?o. Com o intuito de se obter a valida??o da estrat?gia de controle proposta para a UBI, foram realizados testes em laborat?rio utilizando po?os virtuais. Esses testes demonstraram que a estrat?gia desenvolvida conseguiu apresentar desempenho satisfat?rio, isto ?, controlar a UBI, mant?-la dentro dos limites pr?-estabelecidos pelo operador e otimizar a vaz?o de produ??o. / The Sucker-Rod Pump (SRP) system is the most used artificial lift method in oil wells in Brazil and in the world. This method stands out for its simplicity, low cost in investments and maintenance, can be operated in a large range of flowrates and possibility to operate with fluids of different compositions and viscosities. However, the Sucker-Rod Pumping Units, as well as all mechanical equipment, require periodic maintenance, whether corrective or preventive. Two important procedures commonly made at the SRP Units are the adjustment for counterbalancing the pumping unit and the adjustment of the polished rod stroke length. Performing these procedures require stopping the production of the well and are made manually by a team that is moved to the place where the pumping unit is located. In this context, Petrobras in partnership with UFRN and other companies developed a new type of pumping unit, called Smart Sucker-Rod Pump (SSRP), which is capable to counterbalancing the unit and adjust the polished rod stroke length without the need of a team to move to the field. Thus, benefiting from the advantages of the SSRP, this work proposes to develop a strategy to automatically control the Smart Sucker-Rod Pump. The development of this strategy aims to ensure that the equipment both operates under proper conditions and within its safety limits (previously set by the operator), as well as to optimize the well production. In order to validate the control strategy developed for the SSRP, laboratory simulations were performed using virtual wells. It was observed that the developed strategy reached the proposed goals for which it was developed, that is, keep the parameters of the SSRP within the limits set by the operator and optimize the production flowrate.
114

Facebook : uma possível ferramenta de gestão para o PET?

Lima, Francisco Roberto Vasconcelos de. 11 December 2013 (has links)
Dissertação (mestrado)—Universidade de Brasília, Faculdade de Educação, Programa de Pós-Graduação em Educação, Mestrado Profissional em Educação, 2013. / Submitted by Andre Sousa de Sena (andresena1512@icloud.com) on 2014-08-13T18:05:42Z No. of bitstreams: 1 2013_FranciscoRobertoVasconcelosdeLima.pdf: 1256801 bytes, checksum: 7a1afb1df80c46bfe2ead6983f825578 (MD5) / Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2014-08-13T19:24:00Z (GMT) No. of bitstreams: 1 2013_FranciscoRobertoVasconcelosdeLima.pdf: 1256801 bytes, checksum: 7a1afb1df80c46bfe2ead6983f825578 (MD5) / Made available in DSpace on 2014-08-13T19:24:00Z (GMT). No. of bitstreams: 1 2013_FranciscoRobertoVasconcelosdeLima.pdf: 1256801 bytes, checksum: 7a1afb1df80c46bfe2ead6983f825578 (MD5) / O presente estudo intenciona investigar como a Administração Pública, em especial o Ministério da Educação (MEC), através suas políticas públicas e seus programas educacionais, se posiciona frente ao fenômeno das redes sociais virtuais, em especial os websites de relacionamentos com seus dados armazenados na Internet (Web 2.0), mais especificamente, o Facebook. Além disso, buscamos saber se os gestores nacionais e locais do Programa de Educação Tutorial (PET) da SESu/MEC fazem uso do Facebook na gestão de seus grupos. Desse modo, esta pesquisa exploratória analisa o potencial da virtualidade da Web 2.0 e de suas redes sociais na gestão de programas educacionais. A metodologia utilizada no desenvolvimento da pesquisa aqui relatada buscou seguir os postulados de uma pesquisa exploratória. Seu corpus foi examinado por meio da técnica de análise de conteúdo como nos é ensinado por Laurence Bardin. Como modelo teórico de gestão da administração pública, usou-se o proposto por Ana Paula Paes de Paula, ao qual chama vertente societal de gestão da Administração Pública, a qual propõe a maior participação dos cidadãos comuns na condução das políticas públicas, entre outros aspectos sociais importantes. Tal modelo é apresentado nesse trabalho como alternativa à vertente gerencial implantada no período neoliberal dos anos 1990, sobretudo no governo de FHC. Os resultados apontam para o fato de que a gestão dos grupos PET, no âmbito da IES, faz uso de TICs virtuais em sua comunicação. Há unanimidade quando ao uso dos grupos de discussão. Quanto ao uso do Facebook, a pesquisa revela que, apesar dele não ser usados de forma regular por todos os gestores locais, já que nem todos têm uma página oficial do grupo neste espaço virtual, há fortes indícios de que os alunos-bolsistas participantes do PET se interconectam, interagindo no Facebook por meio de suas redes sociais pessoais. Isso proporciona maior rapidez na intercomunicação dos petianos, favorecendo a gestão do grupo. No que tange a interação virtual dos petianos com o público-alvo de seus projetos de extensão, o estudo revelou que ela ainda é escassa devido, sobretudo, às péssimas conexões à internet. A ausência da conexão banda larga inviabiliza o uso das redes sociais nos locais onde desenvolvem seus projetos, em sua maioria escolas que atendem às classes populares do campo e das periferias das grandes cidades. Surpreendentemente, observou-se que o MEC não encoraja o uso do Facebook na gestão de suas políticas educacionais, pois seus técnicos não são autorizados a acessá-lo no ambiente de trabalho sem a devida permissão especial. _______________________________________________________________________________________ ABSTRACT / This study intends to investigate how the federal public administration, especially the Ministry of Education (MEC), through its social policies and educational programs, positions itself on the phenomenon of social networks of the Web 2.0, especially those promoted by the Facebook. In addition to this, we seek to know whether national and local managers of the a certain higher education program offered by SESu/MEC the Tutorial Education Program (PET) make use of Facebook and its social networks in the management of PET groups. The methodology used in the research reported here sought to follow the tenets of an exploratory research. Its corpus was examined by means of content analysis techniques, as taught by Laurence Bardin. As theoretical model of public administration management, we used the model proposed by Ana Paula Paes de Paula, which she calls societal. This approach proposes greater participation of ordinary citizens in the conduct of public policy, among other important social issues. This model, as presented in this work, is an alternative to the present managerial model implemented in the so-called neoliberal period of the 1990s, especially in the FCH administration. The results point to the fact that the management of PET groups within the IES makes use of virtual ICTs in their communication. There is unanimity about the use of discussion groups. Regarding the use of Facebook, the survey reveals that, although it is not used regularly by all local managers (professors-tutors), since not every group has an official page on that website virtual. There is strong evidence that participants of the Program interconnect and interact on Facebook through their personal profiles and networks. Regarding the interaction of petianos with the social group of their extension projects, the study revealed that it is still scarce, mainly due to bad connections to the internet. The lack of internet broadband connection hinders the use of social networks in places where they develop their projects, mostly schools that cater to the working classes of the countryside of the country and suburbs of its large cities.
115

Método dos elementos de contorno aplicado na análise do escorregamento de estacas. / Boundary element method applied in pile slip analysis.

Guilherme Basílio Vick 04 April 2014 (has links)
Neste trabalho apresenta-se um modelo numérico para a análise de problemas tridimensionais envolvendo a interação mecânica estaca-solo, acoplando-se o Método dos Elementos de Contorno (MEC) ao Método dos Elementos Finitos (MEF). O solo é modelado com o MEC utilizando-se as soluções fundamentais de Mindlin, assumindo um meio semi-infinito, homogêneo, isotrópico e elástico-linear. As estacas, modeladas com o MEF, consistem em um elemento único, com quatro nós e 14 parâmetros nodais (três deslocamentos em cada nó e mais duas rotações no topo da estaca). Cada uma das estacas é levada em consideração no MEC como uma linha de carga. Considera-se o escorregamento das estacas em relação ao maciço, empregando modelos de aderência para a definição da evolução das tensões tangenciais ao longo do comprimento das estacas. São empregados, como funções de forma, polinômios do quarto grau para os deslocamentos horizontais, cúbicos para os deslocamentos verticais e tensões horizontais ao longo do fuste e quadráticos para as tensões verticais do fuste e escorregamento. A reação da ponta da estaca é calculada assumindo tensão constante na base. / This work presents a method for tri-dimensional pile-soil interaction problems, by coupling the Boundary Element Method (BEM) to the Finite Element Method (FEM). The soil is modeled with BEM, using the Mindlins fundamental solutions, supposing a semi-infinite, homogeneous, isotropic, elastic and linear space. Piles are modeled with FEM and are represented by one element with four nodes and 14 nodal parameters (three displacements in each node and two rotations at the top node). Each pile is represented in BEM as a line load. The pile slip is considered using adherence models to evaluate the evolution of shaft tractions. There are employed fourth grade polynomial shape functions for horizontal displacements, cubic polynomial functions for vertical displacements and horizontal tractions along shaft and quadratic polynomial functions for vertical tractions and slip. Tip reaction is calculated supposing constant traction at the base.
116

Análise da interação estaca-solo-superestrutura com o acoplamento MEC-MEF / Pile-soil-superstructure interaction using BEM-FEM coupling

Ana Paula Ferreira Ramos 26 September 2013 (has links)
Fundações do tipo radier estaqueado são aquelas formadas pelos elementos estruturais de placa e estacas (elementos de barras) e o solo . Ao contrário de outras tipos de fundações, onde a carga da superestrutura é transferida ao solo pelo radier ou pelas estacas apenas, no radier estaqueado a contribuição das estacas, bem como a do radier são consideradas. As estacas transferem as cargas da superestrutura ao solo e, assim, permitem a redução dos recalques de uma forma muito econômica. O objetivo do presente trabalho é a análise da interação solo-estrutura através do acoplamento MEC-MEF. O solo é considerado um semi-espaço homogêneo, elástico e linear governado pela equação de Navier e modelado pelo Método dos Elementos de Contorno (MEC), admitindo a solução fundamental de Mindlin. As estacas são modeladas pelo Método dos Elementos Finitos (MEF) e cada elemento possui quatro nós. Além disso, as estacas podem receber forças horizontais, verticais e momentos. A tensão de cisalhamento ao longo da estaca é aproximada por um polinômio do segundo grau e as forças na direção horizontal são aproximadas por um polinômio do quarto grau. O elemento de fundação que faz a ligação do pilar com a estaca é representado por uma placa de grande rigidez, que apresenta o comportamento de um bloco. A interação entre o radier estaqueado e o solo é feita através da reação resultante da interação estaca-solo, nos nós com estaca. A interface radier-solo é dividida em elementos triangulares e para a reação do solo considera-se a variação linear ao longo de cada elemento. A superestrutura é modelada pelo MEF. Vários exemplos de interação solo-estrutura são estudados nesta tese, e mostram que as soluções obtidas a partir do programa computacional desenvolvido no presente trabalho denominado SSI estão de acordo com outros autores. / Piled raft foundations are structures consisting of piles, the raft and the soil. Unlike classical foundation design where the building load is either transferred by the raft or the piles alone, in a piled raft foundation the contribution of the piles as well as the raft is taken into account. The piles transfer a part of the building loads into the soil and thereby allow the reduction of settlement in a very economic way. The objective of the present work is the analysis of soil-structure interaction using BEM-FEM coupling. The soil, assumed to be an elastic linear homogeneous half space is governed by Navier\'s equation and it is modeled by the Boundary Elements Method (BEM) using Mindlin\'s fundamental solution. The piles are modeled by the Finite Element Method (FEM) with four nodes each. In addition, the piles can received horizontal and vertical forces and bending moments. The shear traction along the pile is approximated by a second-degree polynomial and the tractions in the horizontal direction are approximated by a fourth degree polynomial. The cap of the pile group is assumed to be rigid. The interaction between the raft and soil is made through the subgrade reaction. The soil-cap interface is divided into triangular elements and the subgrade reaction is assumed to vary linearly across each element. The building\'s structure is modeled by FEM. Several soil structure interaction examples are studied in this thesis, and they show that the solutions obtained from program SSI are in good agreement with others authors.
117

Caracteriza??o de placas de circuito impresso oriundas de telefones celulares e recupera??o de cobre / Circuit boards printed characterization coming from mobile phones and copper recovery

Jesus, Theo Antonio de 23 January 2015 (has links)
Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-06-01T14:05:35Z No. of bitstreams: 1 2015 - Theo Antonio de Jesus.pdf: 3265233 bytes, checksum: 84b1c9854e0877f1a010f74527aca2e5 (MD5) / Made available in DSpace on 2017-06-01T14:05:35Z (GMT). No. of bitstreams: 1 2015 - Theo Antonio de Jesus.pdf: 3265233 bytes, checksum: 84b1c9854e0877f1a010f74527aca2e5 (MD5) Previous issue date: 2015-01-23 / Technological advances encourages the constant exchange of electronic equipment by increasing the amount of waste generated. The concern with the disposal of these wastes is related to the amount of available metals and final disposal, which usually occurs in dumps or landfills. These wastes have precious metals and other trace elements that are released into the environment by leaching from the organic acid attack. Most of these residues has printed circuit boards in which are concentrated the most metals, and the characterization of these plates help to choose the most appropriate recycling processes. This study aimed to characterize the printed circuit boards of mobile phones as its danger and composition as well as preliminarily investigate the possibility of copper recovery via an electrolytic process and test a mixture of coagulant / flocculant in the removal of metals, including copper. The plates were ground knives in order to release the metals and then separating the particle size was made in three fractions of different sizes. Each of the fractions was characterized by digestion in aqua regia, diffraction and X-ray fluorescence characterization, as the danger was performed through recommended by the ABNT NBR 10005. In the fractions resulting from the grain size were performed gravity separations. For the recovery of copper was used in electrolytic technique medium prepared with the electrolyte coming from the gravimetric fraction with a higher concentration of metals. The copper recovery efficiency through electrolytic process was evaluated by the decrease of its concentration in the electrolyte at five different times. Also, the use of coagulant mixture / flocculant had their efficiency assessed by check which proportion coagulant / flocculant used resulted in solution with lower concentrations of metals. It is also made of copper recovery compared by both methods. Mechanical processes are used to promote adequate concentration of most metals with approximately 80% in the coarser fraction using the separation grain size. The characterization results showed that the printed circuit boards of mobile phones are rich in copper, mean values reaching 40%, in addition to having small amounts of gold and silver. In the study of danger, lead levels were found in amounts well above the limit established by ABNT NBR 10004, requiring specific treatments at the disposal of this type of waste. Some proportions coagulant / flocculant used produced better results than others, getting, on average, above 90% removal. The recovery of copper showed better performance using the electrolytic process, compared to that obtained at any ratio coagulant / flocculant used once reached 98.05 % after 40 minutes. It was estimated the average revenue generated in the recovery of metals from the main printed circuit boards of mobile phones discarded in 2013 in Brazil, reaching the amount of US $ 6,182,263.06 / O avan?o tecnol?gico incentiva a troca constante dos equipamentos eletroeletr?nicos aumentando a quantidade de res?duos gerados. A preocupa??o com a disposi??o desses res?duos est? relacionada com a quantidade de metais existentes e sua disposi??o final, que geralmente se d? em lix?es ou aterros. Estes res?duos apresentam metais preciosos e outros elementos tra?os que s?o liberados no meio ambiente pela lixivia??o proveniente do ataque de ?cidos org?nicos. A maior parte destes res?duos possui placas de circuito impresso onde est? concentrada a maior parte dos metais, sendo que a caracteriza??o destas placas ajuda na escolha dos processos de reciclagem mais adequados. Este trabalho teve como objetivo caracterizar as placas de circuito impresso de telefones celulares quanto sua periculosidade e composi??o, bem como investigar preliminarmente a possibilidade de recupera??o de cobre via um processo eletrol?tico e testar uma mistura de coagulante/floculante na remo??o de metais, inclusive cobre. As placas foram processadas em moinho de facas, a fim de liberar os metais e, em seguida, foi feita a separa??o granulom?trica em tr?s fra??es de diferentes tamanhos. Cada uma das fra??es foi caracterizada por digest?o em ?gua r?gia, difra??o e fluoresc?ncia de raios X. A caracteriza??o, quanto ? periculosidade, foi realizada por meio do preconizado pela NBR ABNT 10005. Nas fra??es oriundas da granulometria foram realizadas as separa??es gravim?tricas. Para a recupera??o de cobre foi utilizada a t?cnica eletrol?tica por meio de eletr?lito preparado com a fra??o oriunda da gravimetria com maior concentra??o de metais. A efici?ncia da recupera??o de cobre via processo eletrol?tico foi avaliada por meio da diminui??o de sua concentra??o no eletr?lito em cinco tempos diferentes. J? a utiliza??o da mistura coagulante/floculante teve sua efici?ncia avaliada pela verifica??o de qual propor??o coagulante/floculante utilizada resultou em solu??o com menor concentra??o de metais. Fez-se tamb?m a compara??o de recupera??o de cobre por ambos os m?todos. Os processos mec?nicos utilizados foram adequados para promoverem a concentra??o da maioria dos metais alcan?ando cerca de 80 % na fra??o mais grosseira utilizando-se a separa??o granulom?trica. Os resultados da caracteriza??o mostraram que as placas de circuito impresso de celulares s?o ricas em cobre, alcan?ando valores m?dios de 40 %, al?m de apresentarem pequenas quantidades de ouro e prata. No estudo de periculosidade, foram encontrados n?veis de chumbo em quantidades muito acima do limite estabelecido pela NBR ABNT 10004, sendo necess?rios tratamentos espec?ficos no descarte deste tipo de res?duo. Algumas propor??es de coagulante/floculante utilizadas produziram resultados mais satisfat?rios que outras, ficando, na m?dia, acima dos 90 % de remo??o. A recupera??o de cobre apresentou melhor desempenho utilizando processo eletrol?tico, quando comparado ao obtido a qualquer propor??o de coagulante/floculante utilizada, uma vez que alcan?ou 98,05 % ap?s 40 minutos. Foi estimada a receita m?dia gerada, na recupera??o dos principais metais contidos nas placas de circuito impresso dos telefones celulares, descartados em 2013, no Brasil, chegando-se ao valor de US $ 6.182.263,06.
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Caractérisation de biomarqueurs cellulaires pour étudier la plasticité mammaire au cours de la lactation chez la vache laitière. / Characterization of cell biomarkers for studying mammary gland plasticity throughout lactation in dairy cattle.

Arevalo turrubiarte, Magdalena 28 September 2016 (has links)
La recherche sur la fonction de lactation est indispensable pour la filière laitière. La glande mammaire est un organe composé de cellules épithéliales, de cellules myoépithéliales, de fibroblastes, d’adipocytes et de cellules endothéliales. L’identification et l’évolution en dynamique des populations cellulaires dans la glande mammaire bovine au cours la lactation reste encore à ce jour méconnues. Les objectifs de cette thèse ont été 1) l’obtention d’un panel des biomarqueurs pour identifier les différentes cellules dans la glande mammaire bovine et 2) le suivi de leur évolution au cours d’un cycle de lactation. Les biomarqueurs de surface (CD49f, EpCAM, CD24 et CD10) ont permis de phénotyper deux lignées mammaires bovines. Nous avons également utilisé ces biomarqueurs pour phénotyper les cellules dans la glande mammaire bovine au cours d’un cycle de lactation.Dans cet objectif, des biopsies ont été prélevées sur 5 vaches laitières primipares à quatre étapes durant la lactation. Après la digestion des biopsies, les cellules obtenues ont été marquées et phénotypées par cytométrie en flux. L’analyse des résultats montre des corrélations positives entre les populations cellulaires CD49f+ et CD49f+/CD24- avec la production laitière. Nous avons mis en évidence une population cellulaire CD49f-/EpCAM- qui augmente au cours de la lactation. Ces résultats suggèrent qu’à partir de l’utilisation de biomarqueurs il est possible d’identifier et phénotyper l’évolution de différentes cellules pendant la lactation dans la glande mammaire bovine. / Research of lactation function of the bovine mammary gland remains essential in dairy farming. The mammary gland is an organ composed of epithelial cells, myoepithelial cells, fibroblasts, adipose cells and endothelial cells. The identification and evolution of cell populations in the bovine mammary gland during lactation is currently unknown. The objectives of this thesis were 1) to obtain a panel of biomarkers capable of identifying different cells within the mammary gland 2) to follow the evolution of these cells throughout a lactation cycle. The cell surface biomarkers (CD49f, CD24, CD10 and EpCAM) allowed us to phenotype two bovine mammary cell lines. We also used these cell biomarkers to phenotype cell populations during lactation.For this objective mammary gland explants were obtained by biopsies taken on 5 primiparous lactating cows at four different times during lactation. After the biopsies were digested, the cells obtained were phenotyped by flow cytometry. Analysis of the results revealed a positive correlation between the CD49f+ and CD49f+/CD24- cell populations and milk yield. We also found evidence that one cell population (CD49f-EpCAM-) was increased during lactation. In general these results suggest that biomarker expression can be utilized to identify the phenotype and the evolution of different cell types during lactation in the bovine mammary gland.
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Svaret är 42, men vad är frågan? : En analys av EMEC-modellen och dess effekter på svensk klimatpolitik

André, Hampus, Jonsson, Max January 2015 (has links)
EMEC är en allmänjämviktsmodell som har använts av Konjunkturinstitutet för att beräkna samhällsekonomiska kostnader av styrmedel, och utvärdera kostnadseffektivitet som en del av det svenska klimatpolitiska beslutsunderlaget. Med anledning av kritik som har riktats mot modellen har detta examensarbete syftat till att analysera EMEC och dess effekter i klimatpolitiken, samt belysa och diskutera aspekter som eventuellt behövs utvecklas eller hanteras på ett annat sätt i den svenska klimatpolicyutvärderingen. En intervju - och litteraturstudie bidrog med ett kontrasterande aktörsperspektiv på olika identifierade nyckelaspekter som sedan utgjorde ett ramverk för analysen av en efterföljande empirisk studie. Resultaten visar att det finns starka skäl att påstå att modellen har överskattat kostnader av utsläppsminskningar vilket sannolikt har påverkat Sveriges klimatpolitiska inriktning. I direkt anknytning till modellen argumenteras detta bero på svårigheten i att göra antaganden om framtida teknik-och prisutvecklingar, samt på modellens statiska utformning. I samband med modellens klimatpolitiska roll kan det argumenteras bero på ett relativt kortsiktigt tidsperspektiv och en endimensionell bedömning av klimatomställningens nytta i relation till klimatfrågans långsiktighet och flerdimensionella nyttosida. Det kan också påpekas att detta fördyrar klimatpolitiken på lång sikt. En alternativ klimatpolicyutvärdering tillämpar ett bredare grepp genom att exempelvis inkludera de dynamiska kostnader som är förknippade med inlåsningseffekter i kolintensiva strukturer, vilket med en kontrafaktisk jämförelse sänker kostnaden av en klimatpolicy. Vid fortsatt styrmedelsutvärdering med EMEC föreslås en förändring av hur resultaten ska tolkas. Givet att det politiska sammanhanget också fortsättningsvis kräver kvantitativa underlag finns det ett behov av en mer varierad klimatpolicyutvärdering, där också kvalitativa aspekter och fler indikatorer än BNP beaktas som komplement. / EMEC is a computational general equilibrium (CGE) model used for calculation of societal costs and evaluation of cost-effectiveness in the decision basis of Swedish climate policy. The model has been criticized for exaggerating societal costs of policies, exemplified by Sweden's relative decoupling of GDP and carbon dioxide emissions during 1990-2010. Thereby, one could argue that the model results possibly have led to less ambitious climate targets in Sweden. With the model's suitability being questioned and an expressed need for better climate policy evaluation, this master thesis aims to analyse EMEC and its effects on Sweden's climate policy. It also aims to highlight key aspects for improved climate policy evaluation. Literature and interview studies were conducted in order to form a balanced framework of different actors' perspectives on the issue. This related to several identified aspects that were considered important by the authors in the context of the EMEC model. The subsequent empirical study of three periods of Swedish climate-political processes used these results as a basis for discussion. The results imply that the critique about exaggerated costs very likely is justified, which probably also has affected Sweden's climate-political direction. Regarding the model itself, the principal reasons are argued to be its static nature and the difficulties associated with predicting future technological- and world-market price developments. Connected to the model's role, the principal reasons are argued to be rooted in its relatively short-term perspective and one-dimensional definition of benefits, compared to the long-term and multi-dimensional nature of a transition to a low-carbon society. These features have, in this study, been argued to weaken the long-term cost-effectiveness of Sweden's climate policy. The EMEC-model's principal effects in this respect have been constituted in the arguments for general policies over sector-specific goals as well as emission reductions abroad. An alternative evaluation framework would include a wider range of benefits and costs associated with climate policy, for example dynamic costs of lock-in effects in carbon intensive structures. This would decrease the costs of climate policy in a counter-factual comparison. It could be argued that a qualitative decision basis would be more appropriate considering the complexities and difficulties associated with modelling a largely uncertain future. Especially, since model results are based on the same historic trends that need to be abandoned in order to reach future climate targets. However, considering that the climate-political process demands a quantitative decision-basis, qualitative aspects should function as a complement and gain increased emphasis in the Swedish climate- political decision basis. This would purposively broaden the framework and serve as a necessary balance to the indications given by results on GDP. Given that the EMEC model to some extent continues to constitute a basis for climate policy, suggestions for alternative interpretations of the model results have also been provided.
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Single-Shot, Ultrafast, Multi-Frame X-Ray Imaging of Defect-Bearing Ablator Materials in Extreme Conditions

Hodge, Daniel S. 12 December 2022 (has links)
Characterization of the dynamic behavior of defect-bearing ablator materials subjected to extreme conditions is essential in advancing fusion energy as an reliable and abundant energy source. By understanding how materials evolve spatially and temporally we can minimize hydrodynamic instabilities, which are major contributing factors to energy yield degradation in inertial confinement fusion (ICF) experiments. In this thesis we demonstrate the capabilities of an ultrafast x-ray imaging (UXI) detector, the Icarus V2, where we capture multiple frames of single void-bearing sample compressed by a high-intensity laser shockwave. Using the Matter in Extreme Conditions (MEC) instrument at the Linac Coherent Light Source (LCLS), we conducted two experiments with the x-ray free electron laser (XFEL) multi-pulse mode, delivering four nanosecond-separated pulses to a sample impacted by a laser shockwave, obtaining multiframe images of a single sample in the holographic and direct imaging regime with the UXI detector. In contrast to the low temporal resolution provided by current cameras, the Icarus V2 can capture images with high temporal resolution, which can be used to determine the mechanisms that prevent thermonuclear ignition in ICF experiments. For images captured in the holographic regime at our XFEL energy of 8.23 keV, we realized that the shock front was obscured by strong phase-contrast effects. We recognized that by increasing the XFEL energy while in the holographic regime, more distinguishable features could be revealed behind and along the shock front. Alternatively, in the direct-imaging configuration we discovered that the evolution of microstructural features were directly recognizable in comparison to the holographic regime at lower XFEL energies. Overall, the images captured by the UXI in both regimes demonstrated our ability to obtain multiframe images of processes that occur over several nanoseconds for single samples, which has never been done before. Moreover, the capabilities of the UXI enable extraction of quantitative information over multiple frames, which can help with uncovering the underlying physics involved in high energy density (HED) physics experiments and other experiments involving non-repeatable ultrafast phenomena. Specifically, insight into the behavior of the void can be gained by performing phase retrieval on the images and obtaining the areal density of the materials during laser-shock ablation. Generally, the UXI improves data acquisition speed and operational efficiency, which extends this camera's functionality to experiments that occur at various time scales or experiments that require multiple images to be captured.

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