Made available in DSpace on 2015-04-14T13:33:08Z (GMT). No. of bitstreams: 1 451920.pdf: 503995 bytes, checksum: 18877f49594a02c1abdbc2ab1583ecfb (MD5) Previous issue date: 2013-08-30 / Objective : to evaluate the effects of positive fluid balance in infants under one year with bronchiolitis undergoing mechanical ventilation. Methodos : retrospective cohort study based on analysis of medical records of infants under one year admitted from April 2008 to September 2011 with bronchiolitis requiring mechanical ventilation in a tertiary Pediatric Intensive Care Unit (PICU) in southern of Brazil. We excluded patients with chronic lung disease, tracheostomy and previous use of mechanical ventilation due to acute pulmonary disease. We calculated the cumulative fluid balance within the first 3 days of the onset of mechanical ventilation. The outcomes assessed were ventilator-free days, length of stay in PICU, ventilator parameters used on the third day. Results : eighty-one patients were included in the study, 49 males (60.5%). The mean cumulative fluid balance on the third day of mechanical ventilation was 139 ? 68 ml/kg, the ventilator-free days was 19.7 ? 5.7 and the length of stay in PICU was 10.4 ? 5 6 days. In multivariate analysis, increasing cumulative fluid balance on the third day of mechanical ventilation was associated with a lower number of ventilatorfree days (&#946; -.03; 95% CI -.05, -.01; p <.001). The increasing cumulative fluid balance on the third day was also associated with higher PEEP and higher FiO2 used on the same day (&#946; .01; 95% CI.006, .019; p <.001 and &#946; .09; 95% CI .053, .136; p <.001 respectively). There was no relationship between cumulative fluid balance and length of stay in PICU (p = .950). Conclusion : cumulative fluid balance on the third day of mechanical ventilation is an independent risk factor for a lower number of ventilator-free days in infants under one year with bronchiolitis. There is also an association between higher cumulative fluid balance on the third day of mechanical ventilation and higher PEEP and higher FiO2 on the same day. / Objetivo : avaliar os efeitos do balan?o h?drico positivo em lactentes menores de um ano com bronquiolite viral aguda submetidos ? ventila??o mec?nica. Material e m?todo : estudo de coorte retrospectivo baseado na an?lise de prontu?rios de lactentes menores de um ano admitidos no per?odo de abril de 2008 a setembro de 2011 por bronquiolite viral aguda e submetidos ? ventila??o mec?nica em uma Unidade de Terapia Intensiva Pedi?trica (UTIP) terci?ria no sul do Brasil. Foram exclu?dos os pacientes com doen?a pulmonar cr?nica, traqueostomizados e com uso pr?vio de ventila??o mec?nica devido ? doen?a pulmonar aguda. Foi calculado o balan?o h?drico cumulativo nos primeiros 3 dias do in?cio da ventila??o mec?nica. Os desfechos avaliados foram: dias livres de ventila??o mec?nica, tempo de interna??o na UTIP e par?metros de ventila??o mec?nica utilizados no terceiro dia. Resultados : oitenta e um pacientes foram inclu?dos no estudo, sendo 49 meninos (60,5%). A m?dia do balan?o h?drico cumulativo no terceiro dia de ventila??o mec?nica foi de 139 ? 68 ml/kg, de dias livres de ventila??o mec?nica foi 19,7 ? 5,7 e do tempo de interna??o na UTIP foi 10,4 ? 5,6 dias. Na an?lise multivari?vel, um maior balan?o h?drico cumulativo no terceiro dia de ventila??o mec?nica apresentou associa??o com um menor n?mero de dias livres de ventila??o mec?nica (&#946; -0,03; IC 95% -0,05 a -0,01; p <0,001). O balan?o h?drico cumulativo no terceiro dia tamb?m apresentou associa??o com a utiliza??o de maior PEEP e FiO2 neste mesmo dia (&#946; 0,01; IC 95% 0,006 a 0,019; p <0,001 e &#946; 0,09; IC 95% 0,053 a 0,136; p <0,001 respectivamente). N?o houve rela??o entre balan?o h?drico cumulativo e tempo de interna??o na UTIP (p=0,950). Conclus?o : o balan?o h?drico cumulativo no terceiro dia de ventila??o mec?nica constitui fator de risco independente para um menor n?mero de dias livres de ventila??o mec?nica em lactentes menores do um ano com bronquiolite viral aguda. Existe, tamb?m, associa??o entre um maior balan?o h?drico cumulativo no terceiro dia de ventila??o mec?nica e a utiliza??o de maior PEEP e maior FiO2 neste mesmo dia.

Spatial memory and navigation relies on estimation of location. This can be achieved through several strategies, including the use of landmarks and by path integration. The latter involves inferring location from direction and distance moved relative to a known start point. The neural mechanisms of path integration are not well understood and implementation of experiments that dissociate path integration from alternative strategies is challenging. The roles of specific cell types are also unknown. Although grid cells in layer 2 of the medial entorhinal cortex (MEC) are theorised to be involved given their periodic and repeating firing fields that form a grid-like map that tiles the environment. Two excitatory cell populations have been identified in layer 2 of the MEC. Clusters of pyramidal cells that project to the CA1 are surrounded by dentate gyrus (DG) projecting stellate cells. Both populations have been shown to exhibit grid-like activity. The extent to which these cell types contribute to path integration or other strategies for solving spatial tasks is unknown. To investigate these issues, I developed a spatial memory task for mice, which uses virtual reality to generate sensitive measures of an animal’s ability to path integrate. In this task mice are trained to locate a reward zone marked with a visual cue within a virtual linear track. Use of path integration strategies can be tested in trials in which the reward zone is unmarked. In this task mice can locate the reward zone using either a local beaconing cue or path integration strategies. To assess whether self-motion derived motor information or visual feedback is used for path integration, I manipulated the translation between physical and virtual movement, putting optic and motor feedback in conflict. These manipulations suggest that mice use motor information to locate the reward zone on path integration trials. To test roles of stellate cells in the task I injected adeno-associated virus expressing the light chain of tetanus toxin, conditionally on the presence of Cre, into the MEC of mice expressing Cre specifically in stellate cells. This abolishes synaptic output from stellate cells therefore preventing them from influencing downstream neurons. I find mice with dorsal expression of the tetanus toxin virus in layer 2 stellate cells are unable to locate the reward zone using a local beaconing cue or path integration strategies. In contrast, mice with expression of green fluorescent protein (GFP) were able to locate the reward zone using both strategies. Locating the reward zone using path integration strategies first requires animal’s to learn the reward zone location, as denoted in trials with a beacon cue. To distinguish the role of stellate cells in learning versus execution of the tasks, I temporally modified the activity of stellate cells after mice had learnt to locate the reward zone using both strategies. Temporal control was achieved by use of cre-dependent adeno-associated viruses expressing mutant human muscarinic 4 receptor (hM4). When activated by clozapine - N - oxide (CNO), this receptor opens G-protein inwardly rectifying potassium (GIRK) channels and attenuates neuronal firing. Using this method, the activity of stellate cells can be temporally controlled during task execution and potentially distinguish their involvement in learning and execution of spatial memory tasks. No effect on behavioural performance was seen under these conditions. This may indicate stellate cells are required for learning but not execution of spatial memory tasks that require the use of local beaconing cues or path integration.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2016-07-26T16:32:18Z No. of bitstreams: 1 2016 - Marcelly Alves da Silva.pdf: 1109436 bytes, checksum: cf0918f898aa3347f3dda630016df417 (MD5) / Made available in DSpace on 2016-07-26T16:32:18Z (GMT). No. of bitstreams: 1 2016 - Marcelly Alves da Silva.pdf: 1109436 bytes, checksum: cf0918f898aa3347f3dda630016df417 (MD5) Previous issue date: 2016-02-26 / SILVA, Marcelly Alves da. Using of calcium and magnesium lignosulfonate in mixtures with phenol-formaldehyde in particleboard manufacturing. 2016. 33 p. Dissertation (Master in forest and Environmental Sciences). Instituto de Florestas, Universidade Federal Rural do Rio de Janeiro, Serop?dica, RJ, 2016. The purpose of this study was to evaluate the feasibility of using calcium and magnesium lignosulfonate (LS) in the production of Pinus caribaea var. caribaea particleboard panels, used pure and in mixtures with phenol-formaldehyde (FF). It was determined the basic and apparent density of the wood, as well as the physical and chemical properties of adhesives. In order to evaluate the effect of FF replaced by LS on the physical and chemical properties, panels were produced with different concentrations of these adhesives. The experiment consisted of two phases. The first phase was performed under temperature of 160?C and pressing time of 10 mitutes with the following compositions: 100% FF, and LS substitutions in the proportions of 20, 40, 60, 80 and 100%, with three replications each. In the second phase, the first phase of the three treatments with lower performance in the mechanical properties were tested at a temperature of 180?C and to 7 minutes. The results of basic and apparent wood density were 0.54 and 0.60 g/cm?, respectively. In the second stage the temperature increased and decreased of the pressing time were not sufficient to consolidate the panel, becoming not possible to analyze the results of this phase. In respect to the thickness swelling and water absorption, increases in the proportion of lignosulfonate in the mixture also raise up these values. The substitution of the phenol-formaldehyde adhesive of lignosulfonate was satisfactory in attendance the specific norm for mechanical properties by 80%. The lignosulfonate showed efficiency in the use as an adhesive in the production of particleboard in mixtures with phenol formaldehyde, suggesting that this is an alternative of the use of synthetic adhesives. / SILVA, Marcelly Alves da. Utiliza??o de lignosulfonato de c?lcio e magn?sio em misturas com fenol-formalde?do na produ??o de pain?is aglomerados. 2016. 33 p. Disserta??o (Mestrado em Ci?ncias Ambientais e Florestais). Instituto de Florestas, Universidade Federal Rural do Rio de Janeiro, Serop?dica, RJ, 2016. O objetivo deste estudo foi avaliar a viabilidade da utiliza??o do lignosulfonato de c?lcio e magn?sio (LS) na produ??o de pain?is aglomerados de Pinus caribaea var. caribaea, na forma pura e em misturas com fenol-formalde?do (FF). Foram determinadas a densidade b?sica e aparente da madeira, bem como as propriedades f?sicas e qu?micas dos adesivos. De modo a avaliar o efeito da substitui??o de FF por LS sobre as propriedades f?sicas e qu?micas, foram produzidos pain?is com diferentes concentra??es desses adesivos. O delineamento experimental foi constitu?do de duas fases. A primeira fase foi realizada sob a temperatura de 160?C e tempo de prensagem de 10 minutos, com as seguintes composi??es: 100% de FF, e as substitui??es por LS nas propor??es de 20, 40, 60, 80 e 100%, com tr?s repeti??es cada. Na segunda fase, os tr?s tratamentos da primeira fase com desempenho inferior nas propriedades mec?nicas foram testados na temperatura de 180?C em tempos de prensagem de 5 e 7 minutos. Os resultados m?dios da densidade b?sica e aparente da madeira foram de 0,54 e 0,60g/cm?, respectivamente. Na segunda fase, o aumento da temperatura e a diminui??o do tempo de prensagem n?o foram suficientes para consolidar o painel, n?o sendo poss?vel analisar os resultados desta fase. Com rela??o ao inchamento em espessura e absor??o de ?gua, ? medida que aumentou a propor??o de lignosulfonato na mistura elevaram-se tamb?m esses valores. Em at? 80%, a substitui??o do adesivo fenol-formalde?do por lignosulfonato foi satisfat?ria no atendimento a NBR 14810-2 (ABNT,2013) para propriedades mec?nicas. O lignosulfonato apresentou efici?ncia na utiliza??o como adesivo na produ??o de pain?is aglomerados em misturas com fenol-formalde?do, evidenciando que esta ? uma alternativa ? utiliza??o de adesivos sint?ticos.

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2016-12-06T16:20:59Z No. of bitstreams: 1 DIS_FELIPE_NORNBERG_SCHUCH_COMPLETO.pdf: 1906760 bytes, checksum: 0cbecd09eb2ec152ab66879b383df442 (MD5) / Made available in DSpace on 2016-12-06T16:20:59Z (GMT). No. of bitstreams: 1 DIS_FELIPE_NORNBERG_SCHUCH_COMPLETO.pdf: 1906760 bytes, checksum: 0cbecd09eb2ec152ab66879b383df442 (MD5) Previous issue date: 2016-03-31 / The studies on transport mechanics and sediment deposition in bed slope channels has rapidly increased over the last decade, this is associated with the fact that they play a fundamental role on the formation of hydrocarbon reservoirs. This work aims to investigate, through direct numerical simulation, the plunge phenomena dynamics when a heavier density fluid, full of particles, flows into a lower density environment. Simulations were carried out with Incompact3d, a code based on a Boussinesq system for incompressible fluids was utilized. The channel?s entrance sediment concentration and flow rate influence on the plunge point and deposition profiles were investigated. Results are compared with theoretical models and physical experiments. / O estudo dos mecanismos de transporte e deposi??o dos sedimentos em canal ganhou destaque nas ?ltimas d?cadas, j? que antigos dep?sitos sedimentares no leito do mar formam importantes reservat?rios de hidrocarbonetos. A inten??o desta pesquisa ? investigar, atrav?s de simula??o num?rica direta, a din?mica do fen?meno de mergulho que ocorre quando um escoamento carregado de part?culas em suspens?o adentra em um ambiente de menor densidade. Para tanto, utiliza-se o c?digo computacional Incompact3d, baseado na solu??o da equa??o de Boussinesq para fluidos incompress?veis. ? investigada a influ?ncia da vaz?o e concentra??o de sedimentos na entrada do canal sobre o ponto de mergulho e perfis de deposi??o, e os resultados s?o comparados com modelos te?ricos e experimentos f?sicos.

In this set of studies, a proteomic approach was used to investigate the protein profile of the mammary epithelial cell (MEC) through different stages of mammary development. The HC11 cell line was used to investigate protein changes between undifferentiated and differentiated MEC, which represent the pregnant and lactating states of the cells. This comparison revealed an interesting differential expression profile underscoring many recognized processes that occur in differentiated MECs, while others unveiled differences between MEC differentiation in vitro and in vivo. Primary MEC were also isolated from virgin, pregnant, and primiparous quiescent mice to compare the virgin state of the cell to the other two stages of development. These comparisons added to a previous dataset of primary isolated MEC and generated data that implied a surprising level of activity in virgin MEC relative to the other stages of development investigated. Differentially expressed proteins in the virgin and primiparous quiescent comparison also added to evidence of persisting changes occurring in the gland after a full term pregnancy that are implicated in the risk for breast cancer development. Data sets generated in the same manner from differentiating MEC were used in the development of a database to help manage the growing list of differentially expressed proteins and aid in the identification of potential interesting patterns of regulation during mammary development and differentiation.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-01-15T21:40:49Z No. of bitstreams: 1 OziasFerreiraChavesFilho_DISSERT.pdf: 4227114 bytes, checksum: 2a29900cfc1ea257a9840695d82379b2 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-01-17T15:21:47Z (GMT) No. of bitstreams: 1 OziasFerreiraChavesFilho_DISSERT.pdf: 4227114 bytes, checksum: 2a29900cfc1ea257a9840695d82379b2 (MD5) / Made available in DSpace on 2018-01-17T15:21:47Z (GMT). No. of bitstreams: 1 OziasFerreiraChavesFilho_DISSERT.pdf: 4227114 bytes, checksum: 2a29900cfc1ea257a9840695d82379b2 (MD5) Previous issue date: 2017-08-31 / Recentes trabalhos prop?em a utiliza??o dos ensaios de indenta??o (nanoindenta??o) como uma ferramenta capaz avaliar caracter?sticas (nanoindenta??o) como uma ferramenta capaz de avaliar caracter?sticas mec?nicas filmes finos, assim poss?veis falhas em sistemas que mec?nicas de filmes finos, assim como avaliar poss?veis falhas em sistemas que conjugam alta dureza com substratos met?licos a?o servi?o, conjugam filmes de alta dureza com substratos met?licos de a?o em servi?o, em solicita??es tribol?gicas. Entretanto, implementa??o da t?cnica solicita??es tribol?gicas. Entretanto, a implementa??o da t?cnica de indenta??o para avalia??o do comportamento destes e os seus resultados, para a avalia??o do comportamento destes sistemas e os seus resultados, continuam ocasionando d?vidas no meio cient?fico. Em fun??o destas incertezas continuam ocasionando d?vidas no meio cient?fico. Em fun??o destas incertezas na an?lise ensaio indenta??o, o uso num?rica na an?lise do ensaio de indenta??o, o uso de uma ferramenta num?rica capaz campos tens?es deforma??es durante ciclo de avaliar os campos de tens?es e de deforma??es durante o ciclo de identificando ?reas cr?ticas atrav?s mec?nica indenta??o, identificando poss?veis ?reas cr?ticas atrav?s da mec?nica da fratura, pode auxiliar interpreta??o mais segura deste ensaio. Este fratura, pode auxiliar em uma interpreta??o mais segura deste ensaio. Este trabalho tem proposta utilizar M?todo Elementos Finitos MEF) trabalho tem como proposta utilizar o M?todo dos Elementos Finitos (MEF) em conjunto Modelo Delamina??o Bimodularidade conjunto com o Modelo de Delamina??o e o Modelo de Bimodularidade para simular um filme CrAlN, possui simular ensaios de indenta??o em um filme de CrAlN, que possui uma alta aplicabilidade devido suas propriedades, analisar nuclea??o crescimento aplicabilidade devido a suas propriedades, e analisar a nuclea??o e crescimento trincas, podem ocorrer esses ensaios. Por fim, padr?es de trincas, que podem ocorrer durante esses ensaios. Por fim, os padr?es de surgimento trincas observados neste foram surgimento e crescimento de trincas observados neste trabalho foram comparados obtidos por outros modelos apresentados literatura comparados com os obtidos por outros modelos apresentados na literatura especializada. Tamb?m se concluiu concomitante dois modelosse especializada. Tamb?m se concluiu que o uso concomitante dos dois modelosse mostrou boa estudo nos mostrou uma boa ferramenta para o estudo de falhas nos ensaios de indenta??o finos. em filmes finos. / Recent publications propose the use of indentation testing (nanoindentation) as a tool to evaluate thin film?s mechanical properties, and (nanoindentation) as a tool to evaluate thin film?s mechanical properties, and possible failures in systems that unite high hardness film tribological evaluate possible failures in systems that unite high hardness film (tribological coating) metallic substrates steel, solicitations. However, coating) and metallic substrates of steel, in tribological solicitations. However, the implementation technique for evaluation these implementation of the indentation technique for the evaluation of these systems its results still brings on doubts scientific environment. Due and its results still brings on doubts to the scientific environment. Due to the around tests, numerical able analyze doubts around the indentation tests, the use of a numerical tool able to analyze stress displacement field during cycle, identifying the stress and displacement field during the indentation cycle, identifying possible critical areas using fracture mechanics may help give safer interpretation critical areas using the fracture mechanics may help to give a safer interpretation this test. This work?s proposal is Finite Elements Method FEM) of this test. This work?s proposal is to use the Finite Elements Method (FEM) combined with Delamination Model Cracking Strain simulate combined with Delamination Model and Cracking Strain Model to simulate cycles CrAlN film, has big applicability due indentation cycles on a CrAlN film, a film that has a big applicability due to its crack nucleation growth, which occur properties, and analyze crack nucleation and growth, which may occur during cycles. Finally, patterns growth presented work these cycles. Finally, the patterns of nucleation and growth presented in this work were compared others models specialized literature. Also were compared with others models presented on the specialized literature. Also concluded both together was good study concluded that the use of both models together was a good tool to the study of cracks films. cracks during indentation testing in thin films.

Made available in DSpace on 2014-12-17T14:08:44Z (GMT). No. of bitstreams: 1 FilipeCAL_DISSERT.pdf: 1482396 bytes, checksum: ac4b807c36f7a7406c75156b433df756 (MD5) Previous issue date: 2010-05-07 / This work aims presenting the development of a model and computer simulation of a sucker rod pumping system. This system take into account the well geometry, the flow through the tubing, the dynamic behavior of the rod string and the use of a induction motor model. The rod string were modeled using concentrated parameters, allowing the use of ordinary differential equations systems to simulate it s behavior / Este trabalho visa apresentar a modelagem e a simula??o computacional de um sistema de eleva??o de petr?leo por bombeio mec?nico. Tal sistema leva em considera??o a geometria do po?o, o escoamento do fluido na coluna de produ??o, o comportamento din?mico da coluna de hastes e o uso de um modelo para o motor de indu??o. A coluna de hastes foi modelada de forma a utilizar par?metros concentrados, permitindo o uso de sistemas de equa??es diferenciais ordin?rias na simula??o do comportamento da mesma

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-08-26T23:06:54Z No. of bitstreams: 1 FelipeFernandesCavalcante_DISSERT.pdf: 15830059 bytes, checksum: 1df43f246bc497f6fb2c86ad9f43fb04 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-30T22:45:53Z (GMT) No. of bitstreams: 1 FelipeFernandesCavalcante_DISSERT.pdf: 15830059 bytes, checksum: 1df43f246bc497f6fb2c86ad9f43fb04 (MD5) / Made available in DSpace on 2016-08-30T22:45:53Z (GMT). No. of bitstreams: 1 FelipeFernandesCavalcante_DISSERT.pdf: 15830059 bytes, checksum: 1df43f246bc497f6fb2c86ad9f43fb04 (MD5) Previous issue date: 2016-05-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Sabe-se que a grande parte das ligas de alum?nio pode sofrer varia??es significativas em suas propriedades mec?nicas dependendo do tratamento de envelhecimento realizado. Por?m, poucos trabalhos apontam as caracter?sticas dessas ligas em condi??es subenvelhecidas e superenvelhecidas, principalmente em rela??o ? tenacidade ? fratura. Al?m disso, estudos recentes apontam que algumas ligas de alum?nio subenvelhecidas podem sofrer uma esp?cie de auto cura, ou seja, esses materiais podem, quando solicitados devido a algum esfor?o externo, tender a um fechamento de algum defeito como uma trinca devido ? precipita??o din?mica, o que aumentaria sua capacidade de resistir ?s solicita??es. Neste contexto, neste trabalho ? avaliada a rela??o entre a tenacidade ? fratura e a resist?ncia ? tra??o e as condi??es de tratamentos t?rmicos de duas ligas de alum?nio (2024-T351 e 7075-T651), tanto na condi??o de entrega quanto submetidas a tratamentos t?rmicos de solubiliza??o (a 480 0C por 2,5 h) e envelhecimento artificial (145 0C por 8, 10, 16 e 24 h para a 7075, e 190 0C por 1, 3, 5, 8 e 12 h para a 2024), portanto, em condi??es de subenvelhecimento (abaixo do m?ximo de dureza), envelhecida (no ponto de m?xima dureza) e superenvelhecimento (al?m do ponto de m?xima dureza). Os materiais, nestas diferentes condi??es de processamento foram caracterizados do ponto de vista mec?nico - atrav?s dos ensaios de tenacidade ? fratura, utilizando a metodologia de entalhe chevron - KICVM (ASTM 1304), de tra??o uniaxial (ASTM E8M) e dureza HRB (ASTM E18) - e do ponto de vista estrutural, atrav?s da microscopia ?ptica, MEV e EDS. As microestruturas obtidas nas diferentes condi??es s?o avaliadas por MEV e DR-X. Os micromecanismos de fratura das amostras de tra??o e tenacidade ? fratura s?o avaliados por MEV. Em rela??o ? dureza verificou-se, para ambas as ligas, que ouve apenas um pequena tend?ncia de redu??o dos valores obtidos para a amostras envelhecidas em rela??o ao estado de entrega. Os resultados dos ensaios de tra??o indicam tamb?m uma pequena redu??o da resist?ncia das amostras envelhecidas, em rela??o ao estado de entrega. Estes resultados de dureza e tra??o indicam que a m?xima resist?ncia pode ser obtida para tratamentos de envelhecimento por 5 h (2024) e entre 10 e 12 h (7075). Os resultados de tenacidade ? fratura mostram que n?o houve influ?ncia significativa dos tempos de envelhecimento de 8h, 10h, 16h e 24h sobre os valores de KICV para a liga 7075, apesar dos tratamentos de envelhecimento terem aumentado a tenacidade ? fratura em rela??o ao estado de entrega. Em rela??o ? liga 2024, nem todos os resultados de tenacidade ? fratura puderam ser validados em fun??o da trajet?ria de crescimento de trinca fora do regime de abertura (modo I), mesmo para corpos de prova de maiores dimens?es. Este resultado indica que os diferentes tratamentos de envelhecimento da liga 2024 atuaram no sentido de aumentar a tenacidade do material, elevando a amplitude dos eventos inel?sticos ? frente da trinca. / Heat treatable aluminum alloys may experience significant changes in mechanical properties depending on heat treatment developed. Futhermore, a few works discuss about this properties in underaged and overaged conditions, mainly about fracture toughness. Recently, some researches showed that some aluminum alloys in underaged conditions may indicate the self healing phenomenon, in other words, when streched mechanically, the material could present a closure, or a reduction in crack growth ratio due local compressive stress associated to dynamic precipitation. In this context, its valued the relationship between fracture toughness, mechanical properties and heat treatment in two aluminum alloys (2024-T351 e 7075-T651) when submitted to solubilization (480 ?C for 2,5h) and artificial aging (145 ?C for 8h, 10h, 12h, 16h and 24h for 2024-S1 named first set and 7075; and 190 ?C for 1h, 3h, 5h, 8h and 12h for 2024-S2, second set), obtaining underaged, peak hardness and overaged conditions. The samples were featured using fracture toughness tests with a chevron notch, K??? (ASTM E1304); tensile tests (ASTM E8/E8M) and Vickers hardness (ASTM E 384). In structural aspects, this alloys were featured using optical microscopy and scanning electron microscopy (SEM), in microstructural aspects, using energy-dispersive X-ray spectroscopy (EDS). The micromechanisms of fracture surface on chevron samples are showed using SEM. After results, hardness and ultimate tensile stress showed maximum values between 3h and 5h (2024-S2) and approximately 10h and 12h (7075). About 2024-S2 alloy, it is showed the phenomenon of dynamic precipitation in delivery state, underaged and peak aged samples, due little peaks on stress-strain curves. However, in 2024 first and second sets, all results cannot be valid because the samples showed a significant change in fracture mode presenting a mix of mode I + mode II, futhermore, thickness B is not sufficient for attend ASTM E 1304. The 7075 aluminum alloy presented a distinguished behavior, showing independence in properties like fracture toughness and hadness mainly in overaged conditions, because as the hardness value increase in this condition, fracture toughness increased also. Besides that, K??? values showed no much variation besides the different times of aging, despite this values are much high than delivery state condition. About micromechanisms of fracture, all conditions presented dimples, and cleavage fracture associated to coarse precipitates.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-10-11T20:39:40Z No. of bitstreams: 1 JoaoDantasPaivaVieira_TESE.pdf: 4109014 bytes, checksum: 3983e2c2d433bdb997ed0483f7354aad (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-10-13T23:28:45Z (GMT) No. of bitstreams: 1 JoaoDantasPaivaVieira_TESE.pdf: 4109014 bytes, checksum: 3983e2c2d433bdb997ed0483f7354aad (MD5) / Made available in DSpace on 2016-10-13T23:28:45Z (GMT). No. of bitstreams: 1 JoaoDantasPaivaVieira_TESE.pdf: 4109014 bytes, checksum: 3983e2c2d433bdb997ed0483f7354aad (MD5) Previous issue date: 2015-08-22 / Neste trabalho empregou-se a t?cnica de metaliza??o mec?nica para produzir um revestimento de metal ativo, no caso o tit?nio (Ti), no substrato cer?mico de alumina (Al2O3), a fim de favorecer o molhamento com ligas de adi??o convencionais. Utilizou-se um processo autom?tico com o emprego de uma m?quina ferramenta de controle num?rico computadorizado (CNC) sem a interven??o do operador. Posteriormente, a cer?mica metalizada foi brasada, com tubo met?lico de inox 304, por t?cnica indireta em forno de alto v?cuo, utilizando liga de adi??o convencional Ag-28Cu. A interface resultante foi caracterizada por t?cnica de an?lise micro estrutural em microsc?pio eletr?nico de varredura (MEV) acoplado com sistema de microan?lise qu?mica por energia dispersiva (EDS) e o desempenho mec?nico, por ensaio de cisalhamento, realizado em uma m?quina universal de ensaios mec?nicos, que apresentou baixos valores da tens?o de cisalhamento. A metaliza??o com tit?nio mostrou resultado satisfat?rio com pode ser observado pelas an?lises microsc?picas, enquanto a brasagem apresentou diferen?as significativas, a menor, nos resultados de resist?ncia das amostras analisadas, quando comparadas a outros trabalhos, na mesma ?rea. / In this work employed the mechanical metallization technique to produce a thin film of titanium in the ceramic substrate of alumina (Al2O3), in order to favor wetting with conventional adding alloys. Was used an automated process with employment a machine tool computer numerical control (CNC) without operator intervention. Subsequently, the metallized ceramic was brazed with metallic stainless steel tube 304, by indirect technique in high-vacuum oven, using conventional alloying addition Ag- 28Cu. The resulting interface was characterized by technique of micro structural analysis using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) for chemical microanalysis and mechanical performance, shear test, carried out on a universal testing machine. The titanium metallization film was observed by electron microscopy showing an interface with good interaction between the elements of the materials involved, and the thickness of the layer of titanium fairly regular, consistent with results in the same work area. While brazing interface presented some defects, mainly due to the furnace atmosphere and vacuum pressure, which has not reached the specified value, identified in other studies, which influenced, to some extent, the mechanical results.

Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-22T11:43:42Z No. of bitstreams: 2 lilian_capanema_nogueira.pdf: 2184946 bytes, checksum: 6f6169ea092a767b716bac691cf179f3 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-22T11:44:14Z (GMT) No. of bitstreams: 2 lilian_capanema_nogueira.pdf: 2184946 bytes, checksum: 6f6169ea092a767b716bac691cf179f3 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2014-12-22T11:44:31Z (GMT) No. of bitstreams: 2 lilian_capanema_nogueira.pdf: 2184946 bytes, checksum: 6f6169ea092a767b716bac691cf179f3 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Made available in DSpace on 2014-12-22T11:44:31Z (GMT). No. of bitstreams: 2 lilian_capanema_nogueira.pdf: 2184946 bytes, checksum: 6f6169ea092a767b716bac691cf179f3 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Previous issue date: 2014 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / A ?Restaura??o Biol?gica? ? uma t?cnica que pode oferecer uma excelente biocompatibilidade, desgaste fisiol?gico e mant?m as caracter?sticas est?ticas e funcionais da estrutura do dente tais como brilho de superf?cie, textura, dureza, tamanho, forma, cor e resili?ncia. O objetivo do presente estudo foi comparar pelo ensaio de microtra??o a resist?ncia ? ades?o de restaura??es biol?gicas ap?s cimenta??o no substrato dentin?rio em compara??o as convencionais restaura??es est?ticas cer?micas e analisar suas ?reas de fratura. Foram selecionados vinte e quatro terceiros molares humanos h?gidos, rec?m-extra?dos, que tiveram suas por??es coron?rias seccionadas em dentina e aleatoriamente divididos em dois grupos (n=12), grupo controle (Restaura??es Cer?micas IPS e.max ZirPress) e grupo experimental (Restaura??es Biol?gicas). Para confec??o das restaura??es biol?gicas, discos de dentina foram seccionados com espessura de 2,0 mm cada. Pastilhas de cer?mica foram confeccionadas com as mesmas dimens?es dos discos de dentina. As restaura??es foram cimentadas com cimento resinoso Rely X ARC e ap?s 24 horas submetidos a 10.000 ciclos de termociclagem (5-55?C). Os dentes foram seccionados perpendicularmente ? interface de uni?o, gerando palitos de 1 mm2 e submetidos a ensaio de microtra??o com velocidade de 0,5 mm/min, utilizando uma c?lula de carga de 5Kg. Foi realizada an?lise do padr?o de fratura em lupa estereosc?pica com o aumento de 40x. Esp?cimes representativos foram caracterizados por MEV/EDS para an?lise da morfologia geral e composi??o qu?mica elementar quantitativa dos materiais. Esp?cimes representativos de cada grupo foram submetidas ao protocolo de nanoinfiltra??o com AgNO3 e analisados em MEV. Os dados foram analisados pelo teste t de Student para esp?cimes independentes (p ? 0.05) e do qui-quadrado. N?o foi observada diferen?a estat?stica significativa em rela??o ? resist?ncia ? ades?o. Houve diferen?a significativa (p=0,015) quanto ao tipo de fratura, com 75% de fraturas adesivas para o grupo experimental. As restaura??es biol?gicas apresentaram comportamento semelhante em termos de resist?ncia ? ades?o, quando comparadas ?s restaura??es cer?micas, podendo vir a ser consideradas alternativas para o restabelecimento est?tico-funcional de dentes posteriores. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Odontologia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2014. / ABSTRACT ?Biological restoration? offers excellent biocompatibility and maintains the esthetic and functional characteristics of the tooth, such as physiological wear, surface shine, texture, hardness, size, shape, color and resilience. The aim of the present study was to evaluate the bond strength of biological restorations on dentin in comparison to conventional porcelain restorations through a microtraction test and characterize areas of fracture. The crowns of 24 recently extracted sound human third molars were planed to the dentin and randomly divided into a control group (n = 12; porcelain restorations ? IPS e.max ZirPress) and experimental group (n = 12, biological restorations). Biological restorations were made from fragments of the teeth cut to a thickness of 2.0 mm. Porcelain crowns were made with the same dimensions as the biological fragments. All restorations were cemented with Rely X ARC resin and, after 24 hours, submitted to 10,000 thermal cycles (5 to 55 ?C). The teeth were sectioned perpendicularly to the interface of the union for the obtainment of samples measuring 1 mm2, which were submitted to microtraction using the EZ Test - L universal testing machine operating at 0.5 mm/min with a 5 Kg cell load. Standard fracture analysis was performed with a stereomicroscopic magnifying glass (magnification: 40 x). Representative samples were characterized by scanning electron microscopy (SEM) for the analysis of general morphology and the quantitative element composition of the materials. Additional representative samples from each group were submitted to nano-injection with AgNO3 and analyzed using SEM. Data analysis involved the Student?s t-test for independent samples and the chi-squared test (p ? 0.05). No significant difference in bond strength was found, but a significant difference was found regarding the type of fracture (p = 0.015), with an adhesive fracture rate of 75% in the experimental group. Biological restorations demonstrate similar behavior to that found in porcelain restorations with regard to bond strength and constitute a viable option for the reestablishment of function and esthetics on posterior teeth.