Made available in DSpace on 2014-12-17T15:12:16Z (GMT). No. of bitstreams: 1 BrunoCO_DISSERT.pdf: 1224385 bytes, checksum: e81346840baebc6b478b882c9d426669 (MD5) Previous issue date: 2012-04-13 / The general objective of this dissertation is to analyze the metaphysical aspects of "rational mechanics" of Isaac Newton, clarifying, by scientific and philosophical discourse, their main elements, with emphasis to the presence of one entity infinitely rational behind all the phenomena of nature, and to the Newton's insight as certain empiricist which, however, accepts deductions metaphysics; a philosopher-scientist. The specific objectives are detailed below: a) brief presentation of the development of modern science, since the Pre-Socratics, seeking to understand the historical conjecture that enabled the rise of Newtonian mechanics; b) presentation of the elements of scientific methodology and philosophical, aimed at comprehension of certain "Newtonian methodology", understanding how this specific methodology able to present empirical aspects, mathematics, philosophic and religious in communion; c) to understand, from the Newtonian concepts, both concerning man's role in the world as the "notional notions" of mass, space, time and movement, necessary for analysis and understanding of certain metaphysical aspects in the Newtonian physics; d) to present the Newtonian concepts related to the ether, to understand why it necessarily assumes metaphysics characteristics and mediation between the bodies; e) to present and understand the factors that lead the empiricist Newton to assume the religion in his mechanics, as well as, the existence and functions of God in nature, to object to the higher content of his metaphysics; f) to highlight the metaphysical elements of his classical mechanics, that confirm the presence of concepts like God Creator and Preserver of the natural laws; g) at last, to analyze the importance of Newton to the modern metaphysics and the legacy to philosophy of science at sec. XVII to science contemporary / O objetivo geral dessa disserta??o ? analisar os aspectos metaf?sicos da mec?nica racional de Isaac Newton, esclarecendo, pelo discurso cient?fico e filos?fico, os seus elementos principais, com destaque para a presen?a de uma entidade infinitamente racional por tr?s dos fen?menos de toda a natureza, e para a percep??o de Newton como certo empirista que, no entanto, aceita dedu??es metaf?sicas; um fil?sofo-cientista. Os objetivos espec?ficos podem ser assim enumerados: a) breve apresenta??o do desenvolvimento da ci?ncia moderna, desde os pr?-socr?ticos, buscando compreender os aspectos hist?ricos que possibilitaram o surgimento da mec?nica newtoniana; b) apresenta??o dos elementos da metodologia cient?fica e filos?fica, visando ? compreens?o de certa metodologia newtoniana , compreendendo como essa metodologia espec?fica consegue apresentar aspectos emp?ricos, matem?ticos, filos?ficos e religiosos; c) exposi??o, a partir dos conceitos newtonianos, do papel concernente ao homem no mundo e das no??es nocionais de massa, espa?o, tempo e movimento, necess?rios ? an?lise e compreens?o de certos aspectos metaf?sicos na f?sica de Newton; d) elucidar os conceitos newtonianos referentes ao ?ter, para entendermos por que ele assume necessariamente caracter?sticas metaf?sicas e de media??o entre os corpos; e) apresentar e compreender os fatores que levam o empirista Newton assumir a religi?o na sua mec?nica, bem como, a exist?ncia e fun??es de Deus na natureza, para objetar o conte?do maior de sua metaf?sica; f) evidenciar os elementos metaf?sicos de sua mec?nica cl?ssica, que confirmam a presen?a de conceitos como Deus Criador e Preservador das leis naturais; g) por fim, analisar a import?ncia de Newton para a metaf?sica moderna e a heran?a da filosofia da ci?ncia do s?culo XVII para a ci?ncia contempor?nea

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-04-02T12:49:23Z No. of bitstreams: 1 PoincyanaSonalyBessaDeHolanda_DISSERT.pdf: 3471213 bytes, checksum: d12fe151d13d0d2fef6e1270f2c6bfbb (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-04-04T15:16:34Z (GMT) No. of bitstreams: 1 PoincyanaSonalyBessaDeHolanda_DISSERT.pdf: 3471213 bytes, checksum: d12fe151d13d0d2fef6e1270f2c6bfbb (MD5) / Made available in DSpace on 2018-04-04T15:16:34Z (GMT). No. of bitstreams: 1 PoincyanaSonalyBessaDeHolanda_DISSERT.pdf: 3471213 bytes, checksum: d12fe151d13d0d2fef6e1270f2c6bfbb (MD5) Previous issue date: 2017-11-30 / O Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / O estudo proposto abordar? a an?lise mec?nica, morfol?gica e tintorial de fios e tecidos de malha (estrutura Jersey) produzidos com a fibra de meta-aramida. Inicialmente fios fiados de meta-aramida foram caracterizados atrav?s da an?lise de t?tulo, tor??o e tra??o. Em seguida uma estrutura de malha jersey foi desenvolvida em um tear circular com o intuito de realizar o tingimento deste material com diferentes classes de corantes. Devido a grande dificuldade para se tingir a fibra de meta-aramida, foi proposto um pr?-tratamento com o polieletr?lito cloreto de poli (dialil dimetil am?nio) PDDACL. Posteriormente as amostras antes e ap?s funcionaliza??o e tingimento, foram caracterizadas por meio de ensaios mec?nicos (tra??o, alongamento, fric??o, pilling) e f?sico-qu?micos (an?lise termogravim?trica, calorimetria diferencial de varredura, ?ngulo de contato, espectroscopia no Infravermelho com Transformada de Fourier), complementados por microscopia eletr?nica de varredura. Os tingimentos foram realizados com corantes ?cido, disperso e b?sico em temperaturas 110/120/130?C. Sendo a classe do corante ?cido, utilizada para o planejamento experimental 3?, a fim de se otimizar o processo de tingimento para a obten??o de elevados valores de for?a color?stica. Os efeitos qu?micos da funcionaliza??o da meta-aramida com PDDACL contribu?ram para os melhores resultados obtidos nos valores de for?a color?stica, alcan?ando K/S de 80,38 no ponto ?timo ? 50min, 70?C e com uma concentra??o de 5% spm de PDDACL. As propriedades mec?nicas dos substratos tratados com PDDACL e tintos n?o foram alteradas. Todavia, foi observada uma diminui??o na forma??o de pilling, aumento na hidrofobicidade e uma melhor uniformidade do tingimento nas amostras previamente tratadas. A fibra de meta-aramida degradou a temperaturas superiores a 500?C, e quanto as an?lises de FTIR n?o foi poss?vel identificar novas bandas al?m das presentes no espectro obtido da amostra in Natura, mesmo ap?s a funcionaliza??o. Com rela??o a solidez ? lavagem observou-se uma queda nos valores de K/S, de aproximadamente 3 vezes, por?m a amostra funcionalizada manteve valores de for?a color?stica 2,3 vezes superiores aos valores da amostra sem funcionaliza??o. / This study deals with a mechanical, morphological and tinctorial analysis of yarns and fabrics (Jersey Knit) produced with meta-aramid fiber. Initially, meta-aramid yarns were characterized by titration, torsion and tensile analysis. Aiming to dye the yarns with different dyes, a structure of jersey knit has been developed by using a round loom. Due to the difficulty to dye the meta-aramid fiber, a pre-treatment with a polyelectrolyte poly (diallyl dimethyl ammonium chloride) (PDDACL) has been proposed. Afterwards, the samples have been characterized before and after functionalization and dyeing by mechanical (traction, elongation, friction, pilling) and physical-chemical tests (thermogravimetric analysis, differential scanning calorimetry, contact angle, Fourier-transform infrared spectroscopy(FTIR)), complemented by scanning electron microscopy. The dyeing process has been performed with different dyestuff, such as acid dyes, reactive and basic at temperatures 110/120/130?C. In order to optimize the dyeing process by obtaining high values of color strength, the acid dye class has been used in the 3? experimental design. The chemical effects of the functionalization of meta-aramid with PDDACL contributed to the best results obtained in the color strength values reaching k/s of 80.38 at an optimum point at 50min, 70?C and with a concentration of 5% spm of PDDACL. The mechanical properties of the substrates treated and dyed with PDDACL were not altered. However, we have been observed a decrease in pilling, increase in hydrophobicity and better uniformity of dyeing. The meta-aramid fiber degraded at temperatures higher than 500 ? C, and for the FTIR analysis has been not possible to identify the presence of new bands besides those present in the spectrum obtained from the in-nature sample, even after functionalization. Regarding wash fastness, we have been observed a decrease in K/S values of approximately 3 times was observed, but the functionalized sample maintained values of Color strength 2-3 times higher than the values of the sample without functionalization.

Made available in DSpace on 2014-12-17T14:07:07Z (GMT). No. of bitstreams: 1 MarcioCSM_TESE.pdf: 957118 bytes, checksum: 7c10d815ada900ecb0efde8936a6064e (MD5) Previous issue date: 2011-07-29 / The growing concern with the solid residues management, observed in the last decade, due to its huge amount and impact, has motivated the search for recycling processes, where these residues can be reprocessed to generate new products, enlarging the cycle of materials and energy which are present. Among the polymeric residues, there is poly (ethylene terephthalate) (PET). PET is used in food packaging, preferably in the bottling of carbonated beverages. The reintegration of post-consumer PET in half can be considered a productive action mitigation of environmental impacts caused by these wastes and it is done through the preparation of several different products at the origin, i.e. food packaging, with recycling rates increasing to each year. This work focused on the development and characterization mechanical, thermal, thermo-mechanical, dynamic mechanical thermal and morphology of the pure recycled PET and recycled PET composites with glass flakes in the weight fraction of 5%, 10% and 20% processed in a single screw extruder, using the following analytical techniques: thermogravimetry (TG), differential scanning calorimetry (DSC), tensile, Izod impact, Rockwell hardness, Vicat softening temperature, melt flow rate, burn rate, dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM). The results of thermal analysis and mechanical properties leading to a positive evaluation, because in the thermograms the addition of glass flakes showed increasing behavior in the initial temperatures of thermal decomposition and melting crystalline, Furthermore was observed growing behavior in the mechanical performance of polymer composites, whose morphological structure was observed by SEM, verifying a good distribution of glass flakes, showing difference orientation in the center and in the surface layer of test body of composites with 10 and 20% of glass flakes. The results of DMTA Tg values of the composites obtained from the peak of tan ? showed little reductions due to poor interfacial adhesion between PET and recycled glass flakes. / A crescente preocupa??o com a gest?o de res?duos s?lidos, observada na ?ltima d?cada, em virtude de sua enorme quantidade e impacto ambiental, tem motivado a busca por processos de reciclagem, onde estes res?duos podem ser reprocessados de modo a gerarem novos produtos, ampliando o ciclo dos materiais e energia neles contidos. Dentre os res?duos polim?ricos, destaca-se o poli(tereftalato de etileno) (PET). O PET ? utilizado em embalagens de alimentos, preferencialmente, no envase de bebidas carbonatadas. A reintegra??o do PET p?s-consumo ao meio produtivo pode ser considerada uma a??o mitigat?ria dos impactos ambientais causados por estes res?duos e j? ? realizada por meio da obten??o de diversos produtos diferentes ao da origem, ou seja, embalagens para alimento, com taxas de reciclagem crescente a cada ano. Este trabalho focou o desenvolvimento e a caracteriza??o mec?nica, t?rmica, termo-mec?nica, termo-din?mico-mec?nica e morfol?gica do PET reciclado processado e dos comp?sitos de PET reciclado com flocos de vidro na fra??o em peso de 5%, 10% e 20% processados em uma extrusora rosca simples, utilizando as seguintes t?cnicas de an?lise: termogravimetria (TG), calorimetria explorat?ria diferencial (DSC), tra??o uniaxial, impacto Izod, dureza Rockwel, temperatura de amolecimento Vicat, ?ndice de fluidez, taxa de queima, an?lise termo-din?mico-mec?nica (DMTA) e microscopia eletr?nica de varredura (MEV). Os resultados das an?lises t?rmicas e das propriedades mec?nicas conduziram a uma avalia??o positiva, pois nos termogramas as adi??es dos flocos de vidro mostraram comportamento crescente nas temperaturas inicial de decomposi??o t?rmica e de fus?o cristalina, al?m disso, observou-se comportamento crescente no desempenho mec?nico dos comp?sitos polim?ricos, cuja estrutura morfol?gica foi observada por MEV, verificando uma boa distribui??o dos flocos de vidro, apresentando diferen?a na orienta??o no centro e na camada superficial do corpo de prova dos comp?sitos com 10 e 20% de flocos de vidro. Nos resultados de DMTA os valores de Tg dos comp?sitos obtidos a partir do pico de tan ?, apresentaram pequenas redu??es, devido a pobre ades?o interfacial entre o PET reciclado e os flocos de vidro.

Made available in DSpace on 2014-12-17T14:07:22Z (GMT). No. of bitstreams: 1 JorgeFSO_TESE.pdf: 9384301 bytes, checksum: 94f6528a142b55c3b875e331722c4d8d (MD5) Previous issue date: 2013-12-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / As most current studies, reinforced plastics have been, in recent years, a viable alternative in building structural elements of medium and large, since the lightness accompanied by high performance possible. The design of hybrid polymer composites (combination of different types of reinforcements) may enable structural applications thereof, facing the most severe service conditions. Within this class of composite materials, reinforced the underlying tissues hybrid high performance are taking space when your application requires high load bearing and high rigidity. The objective of this research work is to study the challenges in designing these fabrics bring these materials as to its mechanical characterization and fracture mechanisms involved. Some parameters associated with the process and / or form of hybridization stand out as influential factors in the final performance of the material such as the presence of anisotropy, so the fabric weave, the process of making the same, normative geometry of the specimens, among others. This sense, four laminates were developed based hybrid reinforcement fabrics involving AS4 carbon fiber, kevlar and glass 49-E as the matrix epoxy vinyl ester resin (DERAKANE 411-350). All laminates were formed each with four layers of reinforcements. Depending on the hybrid fabric, all the influencing factors mentioned above have been studied for laminates. All laminates were manufactured industrially used being the lamination process manual (hand-lay-up). All mechanical characterization and study of the mechanism of fracture (fracture mechanics) was developed for laminates subjected to uniaxial tensile test, bending in three and uniaxial compression. The analysis of fracture mechanisms were held involving the macroscopic, optical microscopy and scanning electron microscopy / Conforme estudos mais atuais, os pl?sticos refor?ados v?m sendo, nos ?ltimos anos, uma alternativa vi?vel na constru??o de elementos estruturais de m?dio e grande porte, desde que a leveza acompanhada de alto desempenho seja poss?vel. A concep??o de comp?sitos polim?ricos h?bridos (combina??o entre tipos diferentes de refor?os) pode possibilitar aplica??es estruturais dos mesmos, frente ?s mais adversas condi??es de servi?os. Dentro dessa classe de materiais comp?sitos, os refor?ados a base de tecidos h?bridos de alto desempenho v?m tomando espa?o quando a sua aplica??o requer alto suporte de carga e alta rigidez. O objetivo desse trabalho de investiga??o ? o estudo da influ?ncia que esses tecidos trazem na concep??o desses materiais quanto a sua caracteriza??o mec?nica e mecanismos de fratura envolvidos. Alguns par?metros associados ao processo e/ou forma de hibridiza??o se destacam como fatores influenciadores no desempenho final do material tais como a presen?a de anisotropia, forma da trama tecido, processo de confec??o dos mesmos, geometria normativa dos corpos de prova, entre outros. Neste sentido, quatro laminados comp?sitos foram desenvolvidos ? base de tecidos de refor?os h?bridos envolvendo fibras de carbono AS4, kevlar 49 e vidro-E e como matriz a resina ep?xi ?ster vin?lica (DERAKANE 411-350). Todos os laminados comp?sitos foram constitu?dos com quatro camadas de refor?os. Dependendo do tipo de tecido h?brido, todos os fatores influenciadores acima mencionados foram estudados para os laminados. Todos os laminados foram fabricados industrialmente sendo empregado o processo de lamina??o manual (hand-lay-up). Todo o estudo da caracteriza??o mec?nica e do mecanismo de fratura (fratura mec?nica) foi desenvolvido para os laminados submetidos aos ensaios mec?nicos de tra??o uniaxial, flex?o em tr?s e compress?o uniaxial. As an?lises dos mecanismos de fratura foram realizadas envolvendo a macroscopia, microscopia ?tica e eletr?nica de varredura

Made available in DSpace on 2014-12-17T14:09:19Z (GMT). No. of bitstreams: 1 JonatasALJ_TESE.pdf: 9049452 bytes, checksum: dd9b668c8bc7791108be8a6bbc44e152 (MD5) Previous issue date: 2014-04-28 / A self-flotator vibrational prototype electromechanical drive for treatment of oil and water emulsion or like emulsion is presented and evaluated. Oil production and refining to obtain derivatives is carried out under arrangements technically referred to as on-shore and off-shore, ie, on the continent and in the sea. In Brazil 80 % of the petroleum production is taken at sea and area of deployment and it cost scale are worrisome. It is associated, oily water production on a large scale, carrier 95% of the potential pollutant of activity whose final destination is the environment medium, terrestrial or maritime. Although diversified set of techniques and water treatment systems are in use or research, we propose an innovative system that operates in a sustainable way without chemical additives, for the good of the ecosystem. Labyrinth adsor-bent is used in metal spirals, and laboratory scale flow. Equipment and process patents are claimed. Treatments were performed at different flow rates and bands often monitored with control systems, some built, other bought for this purpose. Measurements of the levels of oil and grease (OGC) of efluents treaty remained within the range of legal framework under test conditions. Adsorbents were weighed before and after treatment for obtaining oil impregna-tion, the performance goal of vibratory action and treatment as a whole. Treatment technolo-gies in course are referenced, to compare performance, qualitatively and quantitatively. The vibration energy consumption is faced with and without conventional flotation and self-flotation. There are good prospects for the proposed, especially in reducing the residence time, by capillary action system. The impregnation dimensionless parameter was created and confronted with consecrated dimensionless parameters, on the vibrational version, such as Weber number and Froude number in quadratic form, referred to as vibrational criticality. Re-sults suggest limits to the vibration intensity / Um prot?tipo vibr?til autoflotador de acionamento eletromec?nico para tratamento de ?gua de produ??o de petr?leo e emuls?o cong?nere ? apresentado e avaliado. A produ??o de petr?leo para refinamento e obten??o de derivados ? realizada sob modalidades tecnicamente referidas como on-shore e off-shore, isto ?, no continente e no mar. No Brasil 80% da produ??o petrol?-fera ? feita no mar e ?rea de implanta??o e escala de custo s?o preocupantes. Associa-se ?gua oleosa de produ??o, efluente abundante em larga escala, carreadora de 95% do potencial polu-idor da atividade cujo destino final ? o meio ambiente mar?timo ou terrestre. Embora diversi-ficado conjunto de t?cnicas e sistemas de tratamento d ?gua encontram-se em uso ou pesqui-sa, prop?e-se um sistema inovador que opera de forma sustent?vel sem aditivos qu?micos, pa-ra o bem do ecossistema. Utilizou-se labirinto adsorvente, em espirais met?licos, e escala la-boratorial de fluxo. Patentes de equipamento e processo s?o reivindicadas. Realizaram-se tra-tamentos em vaz?es e faixas de frequ?ncia distintas, monitoradas com sistemas de controle, uns constru?dos, outros aquistados para tal. Medi??es do teor de ?leo e graxa (TOG) do eflu-ente tratado mantiveram-se dentro do intervalo de enquadramento legal nas condi??es de en-saio. Pesaram-se os adsorventes antes e ap?s o tratamento para obten??o da impregna??o de ?leo, meta de desempenho da a??o vibrat?ria e tratamento como um todo. Tecnologias atuais de tratamento s?o referenciadas para compara??o de desempenho, qualitativa e quantitativa-mente. Confrontou-se consumo energ?tico operando-se em vibra??o, com e sem flota??o con-vencional, e com autoflota??o. Vislumbram-se boas perspectivas de rendimento do sistema proposto, sobretudo, na redu??o do tempo de resid?ncia por a??o de capilaridade. Criou-se o par?metro adimensional de impregna??o e se lhe confrontou com consagrados par?metros a-dimensionais, na vers?o vibracional, como n?mero de Weber e n?mero de Froud quadr?tico, referido como criticalidade vibr?til. Resultados sugerem limites ? intensidade vibrat?ria

Made available in DSpace on 2014-12-17T14:57:56Z (GMT). No. of bitstreams: 1 SergioRLT_TESE_Capa_ate_pag58.pdf: 1954386 bytes, checksum: d88b3653eaeaeec9f2c0ce6f5549f9ef (MD5) Previous issue date: 2014-02-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The growing demand in the use of composite materials necessitates a better understanding of its behavior related to many conditions of loading and service, as well as under several ways of connections involved in mechanisms of structural projects. Within these project conditions are highlighted the presence of geometrical discontinuities in the area of cross and longitudinal sections of structural elements and environmental conditions of work like UV radiation, moisture, heat, leading to a decrease in final mechanical response of the material. In this sense, this thesis aims to develop studies detailed (experimental and semi-empirical models) the effects caused by the presence of geometric discontinuity, more specifically, a central hole in the longitudinal section (with reduced cross section) and the influence of accelerated environmental aging on the mechanical properties and fracture mechanism of FGRP composite laminates under the action of uniaxial tensile loads. Studies on morphological behavior and structural degradation of composite laminates are performed by macroscopic and microscopic analysis of affected surfaces, in addition to evaluation by the Measurement technique for mass variation (TMVM). The accelerated environmental aging conditions are simulated by aging chamber. To study the simultaneous influence of aging/geometric discontinuity in the mechanical properties of composite laminates, a semiempirical model is proposed and called IE/FCPM Model. For the stress concentration due to the central hole, an analisys by failures criteria were performed by Average-Stress Criterion (ASC) and Point-Stress Criterion (PSC). Two polymeric composite laminates, manufactured industrially were studied: the first is only reinforced by short mats of fiberglass-E (LM) and the second where the reinforced by glass fiber/E comes in the form of bidirectional fabric (LT). In the conception configurations of laminates the anisotropy is crucial to the final mechanical response of the same. Finally, a comparative study of all parameters was performed for a better understanding of the results. How conclusive study, the characteristics of the final fracture of the laminate under all conditions that they were subjected, were analyzed. These analyzes were made at the macroscopic level (scanner) microscope (optical and scanning electron). At the end of the analyzes, it was observed that the degradation process occurs similarly for each composite researched, however, the LM composite compared to composite LT (configurations LT 0/90? and LT ?45?) proved to be more susceptible to loss of mechanical properties in both regarding with the central hole as well to accelerated environmental aging / A crescente demanda na utiliza??o dos materiais comp?sitos torna imprescind?vel uma melhor compreens?o do seu comportamento frente ?s mais diversas condi??es de carga e servi?o, bem como sob as variadas formas de conex?es envolvendo mecanismos nos projetos estruturais. Dentro dessas condi??es de projeto destaque se faz para a presen?a de descontinuidades geom?tricas na ?rea de se??es transversal e ou longitudinal dos elementos estruturais, assim como, condi??es ambientais de servi?o como a radia??o UV, a umidade, o calor, que levam a um decr?scimo na resposta mec?nica final do material. Neste sentido, essa tese tem como objetivo o desenvolvimento de estudos (experimental e modelos semi-emp?ricos) detalhados dos efeitos causados pela presen?a de descontinuidade geom?trica, mais especificamente um furo conc?ntrico na se??o longitudinal (com redu??o da se??o transversal), assim como, da influ?ncia do envelhecimento ambiental acelerado nas propriedades mec?nicas e mecanismo de fratura de laminados comp?sitos de PRFV sob a a??o de cargas uniaxiais de tra??o. Estudos referentes ao comportamento morfol?gico e de degrada??o estrutural dos laminados comp?sitos s?o realizados, atrav?s de an?lises macrosc?picas e microsc?picas das superf?cies afetadas, al?m da avalia??o mediante a T?cnica de Media??o de Varia??o de Massa (TMVM). As condi??es de envelhecimento ambiental acelerado ser?o simuladas atrav?s da c?mara de envelhecimento. Para avalia??o da influ?ncia simult?nea do envelhecimento/descontinuidade geom?trica nas propriedades mec?nicas dos laminados comp?sitos, um modelo semi-empirico ? proposto e denominado de Modelo IE/FCPM. Para o caso da presen?a da concentra??o de tens?o devido ao furo conc?ntrico, a mesma ? avaliada a partir do uso dos crit?rios de falhas da Tens?o M?dia (Average-Stress Criterion) e da Tens?o Pontual (Point-Stress Criterion). Dois laminados comp?sitos polim?ricos, confeccionados industrialmente, foram estudados: o primeiro ? unicamente refor?ado com mantas de fibras curtas de vidro/E (LM) e o segundo onde o refor?o de fibras de vidro/E vem na forma de tecido bidirecional (LT). Na concep??o das configura??es dos laminados a presen?a da anisotropia ? fundamental para a resposta mec?nica final dos mesmos. Por fim, um estudo comparativo entre todos os par?metros foi realizado para uma melhor compreens?o dos resultados. Como estudo conclusivo, as caracter?sticas da fratura final dos laminados sob todas as condi??es que os mesmos foram submetidos, foram analisadas. Essas an?lises foram feitas em n?veis macrosc?pico (scanner) microsc?pico (?ptico e eletr?nico de varredura). Ao t?rmino das an?lises foi observado que o processo de degrada??o se d? de forma semelhante para cada comp?sito pesquisado, no entanto, o laminado comp?sito LM quando comparado ?s configura??es LT 0/90? e LT ?45? do laminado comp?sito LT, se mostrou mais suscept?vel a perda de propriedades mec?nicas tanto em rela??o ? presen?a do furo conc?ntrico como em rela??o ao envelhecimento ambiental acelerado

Made available in DSpace on 2014-12-17T14:58:15Z (GMT). No. of bitstreams: 1 MayaraSCFL_DISSERT.pdf: 5165682 bytes, checksum: c5b249c3b897f27db4e517452be9b9ce (MD5) Previous issue date: 2012-04-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Composites based on PEEK + PTFE + CARBON FIBER + Graphite (G_CFRP) has increased application in the top industries, as Aerospace, Aeronautical, Petroleum, Biomedical, Mechanical and Electronics Engineering challenges. A commercially available G_CFRP was warmed up to three different levels of thermal energy to identify the main damage mechanisms and some evidences for their intrinsic transitions. An experimental test rig for systematize a heat flux was developed in this dissertation, based on the Joule Effect. It was built using an isothermal container, an internal heat source and a real-time measurement system for test a sample by time. A standard conical-cylindrical tip was inserted into a soldering iron, commercially available and identified by three different levels of nominal electrical power, 40W (manufacturer A), 40W (manufacturer B), 100W and 150W, selected after screening tests: these power levels for the heat source, after one hour of heating and one hour of cooling in situ, carried out three different zones of degradation in the composite surface. The bench was instrumented with twelve thermocouples, a wattmeter and a video camera. The twelve specimens tested suffered different degradation mechanisms, analyzed by DSC (Differential Scanning Calorimetry) and TG (Thermogravimetry) techniques, Scanning Electron Microscopy (SEM) and Energy-Dispersive X-Rays (EDX) Analysis. Before and after each testing, it was measured the hardness of the sample by HRM (Hardness Rockwell M). Excellent correlations (R2=1) were obtained in the plots of the evaporated area after one hour of heating and one hour of cooling in situ versus (1) the respective power of heat source and (2) the central temperature of the sample. However, as resulting of the differential degradation of G_CFRP and their anisotropy, confirmed by their variable thermal properties, viscoelastic and plastic properties, there were both linear and non-linear behaviour between the temperature field and Rockwell M hardness measured in the radial and circumferential directions of the samples. Some morphological features of the damaged zones are presented and discussed, as, for example, the crazing and skeletonization mechanism of G_CFRP / Comp?sitos baseados em matrizes polim?ricas de PEEK e PTFE, refor?adas com fibra de carbono e grafite (G_CFRP) apresentam crescente aplica??o e desafios ? Engenharia nas ind?strias Aeroespacial, Aeron?utica, de Petr?leo, Biom?dica, Mec?nica e Eletr?nica. Um comp?sito G_CFRP foi aquecido em tr?s n?veis de energia t?rmica para identificar os principais mecanismos de dano e algumas evid?ncias em suas transi??es de mecanismos. Uma bancada experimental foi desenvolvida para sistematizar o fluxo t?rmico com base no Efeito Joule. Foi constru?da usando-se um recipiente isot?rmico, uma fonte quente interna e um sistema de medidas em tempo real para ensaiar um corpo-de-prova (CP) de cada vez. Uma ponta c?nica-cil?ndrica foi inserida em um ferro de soldar, comercialmente dispon?vel e identificado por tr?s diferentes n?veis de pot?ncia el?trica, 40W (fabricante A), 40W (fabricante B), 100W e 150W, selecionados ap?s ensaios piloto: estes n?veis de pot?ncia para a fonte quente, ap?s uma hora de aquecimento e uma hora de resfriamento in situ, promoveu tr?s zonas diferentes de degrada??o na superf?cie do comp?sito. A bancada foi instrumentada com doze termopares, um watt?metro e uma c?mera de v?deo. Os doze C.P. ensaiados apresentaram diferentes mecanismos de degrada??o, analisados pelas t?cnicas de Calorimetria Diferencial Explorat?ria (DSC) e Termogravimetria (TG), e pelas an?lises de Microscopia Eletr?nica de Varredura (MEV) e Energia Dispersiva de Raios-X (EDS). Antes e ap?s cada ensaio, foram feitos ensaios de dureza Rockwell M (HRM). Excelentes correla??es (R2=1) foram obtidas nas curvas da ?rea evaporada ap?s uma hora de aquecimento e uma hora de resfriamento in situ versus (1) a respectiva pot?ncia da fonte quente e (2) a temperatura central do C.P. entretanto, como resultado da degrada??o diferencial do G_CFRP e da sua anisotropia, confirmadas por suas propriedades t?rmicas vari?veis, propriedades viscoel?sticas e viscopl?sticas, houve comportamentos linear e n?o-linear entre o campo de temperatura e a HRM medidos nas dire??es radial e circunferencial dos C.P. Algumas peculiaridades morfol?gicas das zonas de dano s?o apresentadas e discutidas, como, por exemplo, os mecanismos de dano por crazing e esqueletiza??o do G_CFRP

Made available in DSpace on 2014-12-17T15:14:49Z (GMT). No. of bitstreams: 1 AlzeyGF.pdf: 1374839 bytes, checksum: 04a6f9d10ed4cb9e18af438a89ba7f26 (MD5) Previous issue date: 2008-10-02 / Systems whose spectra are fractals or multifractals have received a lot of attention in recent years. The complete understanding of the behavior of many physical properties of these systems is still far from being complete because of the complexity of such systems. Thus, new applications and new methods of study of their spectra have been proposed and consequently a light has been thrown on their properties, enabling a better understanding of these systems. We present in this work initially the basic and necessary theoretical framework regarding the calculation of energy spectrum of elementary excitations in some systems, especially in quasiperiodic ones. Later we show, by using the Schr?odinger equation in tight-binding approximation, the results for the specific heat of electrons within the statistical mechanics of Boltzmann-Gibbs for one-dimensional quasiperiodic systems, growth by following the Fibonacci and Double Period rules. Structures of this type have already been exploited enough, however the use of non-extensive statistical mechanics proposed by Constantino Tsallis is well suited to systems that have a fractal profile, and therefore our main objective was to apply it to the calculation of thermodynamical quantities, by extending a little more the understanding of the properties of these systems. Accordingly, we calculate, analytical and numerically, the generalized specific heat of electrons in one-dimensional quasiperiodic systems (quasicrystals) generated by the Fibonacci and Double Period sequences. The electronic spectra were obtained by solving the Schr?odinger equation in the tight-binding approach. Numerical results are presented for the two types of systems with different values of the parameter of nonextensivity q / Sistemas cujos espectros s?o fractais ou multifractais t?m sido bastante estudados nos ?ltimos anos. O entendimento completo do comportamento de muitas propriedades f?sicas destes sistemas ainda est? longe de ser completamente efetivado devido ? complexidade dos pr?prios sistemas. Desta maneira, novas aplica??es e novos m?todos de estudo dos seus espectros t?m sido feitos, possibilitando uma melhor compreens?o acerca desses sistemas. Apresentamos neste trabalho de disserta??o inicialmente todo o arcabou?o te?rico b?sico e necess?rio no tocante ? obten??o dos espectros de energia de excita??es elementares em alguns sistemas, mais especificamente nos sistemas quasiperi?dicos. Posteriormente mostramos, usando a equa??o de Schrodinger na aproxima??o de liga??o forte, os resultados para o calor espec?fico de el?trons com a mec?nica estat?stica de Boltzmann-Gibbs para sistemas quasiperi?dicos unidimensionais tipo Fibonacci e Per?odo Duplo. Estruturas desse tipo j? foram bastante exploradas, no entanto o uso da mec?nica estat?stica n?o-extensiva proposta por Constantino Tsallis ? bem adequado para sistemas que apresentam de alguma forma um perfil fractal, e portanto nosso principal objetivo foi aplic?-la para o c?lculo de grandezas termodin?micas ampliando um pouco mais a compreens?o das propriedades desses sistemas. Neste sentido, calculamos anal?tica e numericamente o calor espec?fico generalizado de el?etrons em sistemas quasiperi?dicos unidimensionais (quasicristais) gerados pelas sequ?ncias de Fibonacci e Per?odo Duplo. Os espectros eletr?nicos foram obtidos fazendo-se uso tamb?m da equa??o de Schrodinger na aproxima??o de liga??o forte. Resultados num?ricos s?o apresentados para os dois tipos de sistemas com diferentes valores do par?metro de n?o-extensividade q

Made available in DSpace on 2014-12-17T15:14:59Z (GMT). No. of bitstreams: 1 TiagoMV_DISSERT.pdf: 2054032 bytes, checksum: 01cc6c903e54670f8c4b846fab645cd0 (MD5) Previous issue date: 2012-02-24 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / This dissertation briefly presents the random graphs and the main quantities calculated from them. At the same time, basic thermodynamics quantities such as energy and temperature are associated with some of their characteristics. Approaches commonly used in Statistical Mechanics are employed and rules that describe a time evolution for the graphs are proposed in order to study their ergodicity and a possible thermal equilibrium between them / Esta disserta??o apresenta brevemente os grafos aleat?rios e as principais quantidades calculadas a partir deles. Ao mesmo tempo, grandezas b?sicas da Termodin?mica como energia e temperatura s?o associadas a algumas de suas caracter?sticas. Abordagens comumente utilizadas na Mec?nica Estat?stica s?o empregadas e regras que descrevem uma evolu??o temporal para os grafos s?o propostas com o objetivo de estudar sua ergodicidade e um poss?vel equil?brio t?rmico entre eles

Made available in DSpace on 2014-12-17T15:15:01Z (GMT). No. of bitstreams: 1 AndreAAM_TESE.pdf: 2226063 bytes, checksum: fe5fa44772a8628a39e211a6a6d4e925 (MD5) Previous issue date: 2014-04-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / We address the generalization of thermodynamic quantity q-deformed by q-algebra that describes a general algebra for bosons and fermions . The motivation for our study stems from an interest to strengthen our initial ideas, and a possible experimental application. On our journey, we met a generalization of the recently proposed formalism of the q-calculus, which is the application of a generalized sequence described by two parameters deformation positive real independent and q1 and q2, known for Fibonacci oscillators . We apply the wellknown problem of Landau diamagnetism immersed in a space D-dimensional, which still generates good discussions by its nature, and dependence with the number of dimensions D, enables us future extend its application to systems extra-dimensional, such as Modern Cosmology, Particle Physics and String Theory. We compare our results with some experimentally obtained performing major equity. We also use the formalism of the oscillators to Einstein and Debye solid, strengthening the interpretation of the q-deformation acting as a factor of disturbance or impurity in a given system, modifying the properties of the same. Our results show that the insertion of two parameters of disorder, allowed a wider range of adjustment , i.e., enabling change only the desired property, e.g., the thermal conductivity of a same element without the waste essence / Abordamos a generaliza??o das quantidades termodin?micas q-deformadas atrav?s da q-?lgebra que descreve uma ?lgebra generalizada para b?sons e f?rmions. A motiva??o para o nosso estudo surge do interesse de fortalecer nossas id?ias iniciais, a fim de propor uma poss?vel aplica??o experimental. Em nossa jornada, conhecemos uma generaliza??o recentemente proposta ao formalismo do q-c?lculo, que ? a aplica??o de uma seq??ncia generalizada, descrita por dois par?metros de deforma??o reais positivos e independentes q1 e q2, conhecidos por osciladores de Fibonacci. Aplicamos ao conhecido problema do diamagnetismo de Landau imerso em um espa?o D-dimensional, que ainda gera boas discuss?es por sua natureza, e a depend?ncia com o n?mero de dimens?es D, nos possibilita futuramente estendermos a sua aplica??o para sistemas extra-dimensionais, tais como a CosmologiaModerna, a F?sica de Part?culas e Teoria de Cordas. Comparamos nossos resultados com alguns obtidos experimentalmente, apresentando grande equival?ncia. Aplicamos ainda o formalismo dos osciladores aos s?lidos de Einstein e Debye, fortalecendo ? interpreta??o da q-deforma??o atuando como um fator de perturba??o ou impureza, num determinado sistema, modificando as propriedades do mesmo. Nossos resultados mostram que a inser??o de dois param?tros de desordem, possibilitaram uma maior faixa de ajuste, ou seja, possibilitando alterar apenas a propriedade desejada, por exemplo, a condutividade t?rmica de um elemento sem que o mesmo perca sua ess?ncia .