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Estudo do desgaste de nanocompósitos de alumina-zircônia usando variação de parâmetros no ensaio pino-no-disco / Wear study of alumina-zirconia nanocomposites using variation of parameters in the pin-in-disk testAna Carolina Gomez 23 October 2017 (has links)
O desgaste é responsável por um grande número de falhas em materiais, provocando a sua substituição antecipada e consequentemente diminuindo a sua vida útil. Por isso, estudos são realizados para caracterizar os limites de utilização desses materiais, evitando assim situações catastróficas. A partir das variáveis e parâmetros envolvidos no ensaio de desgaste, é possível construir mapas que tem como finalidade direcionar para uma correta escolha do material, de acordo com a aplicação desejada, além de identificar o seu comportamento frente à determinadas condições de uso. Neste contexto, este trabalho teve como objetivo conhecer o comportamento de desgaste de nanocompósitos de alumina contendo 5% de inclusões nanométricas de zircônia, visando construir um diagrama de transição de desgaste entre os limites de combinação de velocidade de deslizamento e carga aplicada. Para isso, corpos de prova conformados na forma de pinos com uma das extremidades semiesféricas foram caracterizados quanto a dureza e tenacidade à fratura, submetidos ao ensaio de desgaste do tipo pino-no-disco com temperaturas e umidades ambientes, variando os parâmetros de velocidade e carga. As velocidades de deslizamento variaram de 1,2 m/s à 0,1 m/s e as cargas variaram de 2 N à 100 N. Os valores de dureza e tenacidade a fratura obtidos foram de 14,08 ± 1,22 GPa e 3,99 ± 0,14 MPa.m1/2, respectivamente. Os resultados de desgaste mostraram que a partir da caracterização e construção do diagrama de transição de regime de desgaste, com combinações de parâmetros extrínsecos de carga e velocidade de deslizamento, foi possível definir e atingir as condições limites entre o regime de desgaste moderado e a transição para o regime severo. Esse diagrama auxilia na seleção e comparação da transição entre os limites de desgaste do material estudado com outros tipos usados na engenharia. / Wear is responsible for a large number of material failures, causing them to be replaced early and consequently shortening their life-time. Therefore, studies are conducted to characterize the limits of use of these materials, thus avoiding catastrophic situations. From the variables and parameters involved in the wear test, it is possible to construct maps that aim to direct the correct choice of material according to the desired application, as well as to identify its behavior against certain conditions of use. In this context, the objective of this work was to know the wear behavior of alumina nanocomposites containing 5% nanometric zirconia inclusions in order to construct a simplified wear transition diagram between the sliding speed and applied load combination limits. For this, test pieces shaped like pins with semi-spherical tips were characterized in terms of hardness and fracture toughness, took to the wear test of the pin-on-disk with ambient temperatures and humidity, varying the speed and load parameters. Slip velocities ranged from 1.2 m/s to 0.1 m/s and loads ranged from 2 N to 100 N. The values of hardness and fracture toughness obtained were 14.08 ± 1.22 GPa and 3.99 ± 0.14 MPa.m1/2, respectively. The results of wear showed that from the characterization and construction of the wear regime transition diagram, with combinations of extrinsic load parameters and slip speed, it was possible to define and reach the boundary conditions between the moderate wear regime and the transition for the severe regime. This diagram helps in the selection and comparison of the transition between the wear limits of the studied material with other types used in engineering.
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Expressão de receptores de EGF, inibidores e reguladores do ciclo celular em lesões proliferativas da próstata canina / Expression of EGF rececptors, cell cycle inhibitors and regulators in canine prostate with proliferative lesionsFaleiro, Mariana Batista Rodrigues 14 November 2014 (has links)
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Previous issue date: 2014-11-14 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Somedysplastic lesionsof prostate, such as proliferativeinflammatoryatrophy (PIA) and
prostatic intraepithelial neoplastic(PIN) are proliferative,consideredpremalignant andcan
progress toprostatic carcinoma (PC). Others, such asbenign prostatichyperplasia(BPH) are
proliferative, butare not related tomalignancy.The humanPC is the one ofcancers that more
kill,and dog`sthe onlyanimal species thatpresentsadiseasewith similarcharacteristics, thishas
been usedas a modelfor studyof prostatecancer. Thus, in order tobetter understandthe
molecular mechanisms involvedin repairand cell cycleevolution ofproliferative
lesionsincanine prostate, this study aimed to evaluatethe gene expression ofErbB1, ErbB2,
CDKN1A, CDKN1BandTP53andimmunostaining ofEGFR(Her1), Her2(c-erbB-2), p21,
p27and p53 inprostateswithPIAandPC. Also was evaluatedtheimmunostaining ofp21, p27,
p53, c-myc andcyclinD1inprostateswith BPH, PIA, PINandPC. For this purpose,wereobtained
from atissue microarray (TMA)block, 106samplesofcanineprostate tissue, which 15 normal,
16with BPH, 30 withPIA, 20 with PIN, and 25with CP. The RT-PCR andRT-qPCR
techniques wereused to evaluategene expression, as well as immunohistochemistrywas used
to determinetheimmunophenotypeofprostatic lesions. As forEGFRand Her2has beenobserved
that thesereceptorsactin canine lesions withPIA and with PCan importantaction ofHer2,
suggesting that theyare involvedin carcinogenesisandtumor development in canineprostate.
Regarding to cellcycleinhibitor concludethat whenoverexpressedin canine
prostateswithPIAandPC, p21andp27control cellproliferation, acting as a protective factorin
the evolution of PIA to PC, and in the PC development, even in the presence of altereted p53.
In assessing ofimmunostaining ofcell cycle regulators(p21, p27, p53, cyclinD1andc-myc) in
canineprostateswithproliferative lesionswas observedthatcarcinomas probably have
lowgrowth potentialwhenoverexpressed of p21andp27, reduced expression of cyclinD1and
unalteredexpression ofc-myc, even in the presence ofmutant p53type.Further,considering
thesimilarimmunophenotypein canine glands with PIA, PINandPC considered the
regulatorsofcell cycle progression, it is reinforce the pre-malignant potential of PIA andPINin
the canineprostate. / Algumas lesões displásicas da próstata, como a atrofia inflamatória proliferativa (PIA) e a
neoplasia intraepitelial prostática (PIN), são proliferativas, consideradas pré-malignas e
podem evoluir para carcinoma prostático (PC). Outras, como a hiperplasia prostática benigna
(HPB), apesar de proliferativas, não possuem relação com malignidade. Sendo o PC humano
uma das neoplasias que mais matam, e o cão aúnica espécie animal que apresenta a
enfermidade com características semelhantes, esta tem sido utilizada como modelo para o
estudo do câncer de próstata. Assim, com o intuito de melhor compreender os mecanismos
moleculares envolvidos na regulação do ciclo celular e evolução das lesões proliferativas na
próstata canina, este estudo teve por objetivo avaliar a expressão gênica de ErbB1, ErbB2,
CDKN1A, CDKN1B e TP53,e imunomarcação deEGFR (Her1), Her2 (c-erbB-2), p21, p27 e
p53 em próstatas com PIA e PC. Também foi avaliada a imunomarcação de p21, p27, p53, cmyc
e cyclin D1 em próstatas com HPB, PIA, PIN e PC. Para tal, foram obtidas de um bloco
de microarranjo tecidual (TMA) 106 amostras de tecido prostático canino, sendo 15 normais,
16com HBP, 30com PIA, 20com PIN, e25com PC. As técnicas de RT-PCR e RT-qPCR
foram empregadas na avaliação da expressão gênica, assim como a técnica de
imunoistoquímica foi utilizada para verificar o imunofenótipo das lesões prostáticas. Quanto
aos receptores EGFReHer2 foi observado que esses atuam naslesões de PIAePCcanino, com
ação importante do receptor Her2, sugerindoqueessesestão envolvidosna carcinogênese e no
desenvolvimentotumoral da prostata canina.Em relação aos inibidores do ciclo celular
councluiu-se que quando superexpressos em próstatas com PIA e PC, p21 e p27 controlam a
proliferação celular, atuando comofator protetivo na evolução da PIA para PC, e no
desenvolviemento do PC, mesmo quando da alteração de p53. Na avaliação da
imunoexpressão dos reguladores do ciclo celular (p21, p27, p53, ciclina D1 e c-myc) em
próstatas caninas com lesões proliferativas foi constatado que os carcinomas possivelmente
apresentam baixo potencial de crescimento quando da superexpressãop21 ep27, menor
subexpressão de ciclina D1e expressão inalterada de c-myc, mesmo na presença de p53 tipo
mutante. Ainda, considerando o imunofenótipo semelhante nas glândulas com PIA, PIN e PC
no que se refere aos reguladores daprogressão do ciclo celular, reforça o potencial prémaligno
da PIA e PIN na próstata canina.
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Análise biomecânica de resistência à fratura em dentes caninos artificiais de cães, com restauração metálica fundida e retentores intrarradiculares retos e curvos com núcleo - Estudo comparativo com análise por elementos finitos / Biomechanical analysis of resistance to fracture in artificial dog canine teeth with cast metal restoration and straight and curved intrarradiculares retainers with core - Comparative study with finite element analysisSergio Luiz da Silveira Camargo 11 March 2016 (has links)
Os cães, por fatores diversos, acabam por apresentar dentes fraturados com ou sem exposição de polpa. Estas fraturas basicamente são identificadas como fraturas recuperáveis não complicadas, recuperáveis complicadas ou irrecuperáveis. As fraturas recuperáveis (localizadas apenas no esmalte e dentina) são tratadas com dentística restauradora. As recuperáveis complicadas (com lesões em esmalte, dentina e exposição do canal radicular) passam por tratamento endodôntico, podendo ser seguidas de restaurações metálicas. Os dentes mais comumente acometidos são os dentes caninos, superiores ou inferiores. Este trabalho em dentes artificiais simulando considerável destruição de sua porção coronal objetivou testar, após a adaptação da restauração metálica fundida, a resistência às fraturas no dente canino. Os dentes artificiais foram padronizados com uma técnica de replicação de raízes artificiais em molde de resina acrílica quimicamente ativada. Oitenta réplicas iguais de resina composta fotopolimerizável, padronizadas em tamanho e forma, foram construídas a partir desta técnica. Antes da reconstrução protética, aplicou-se o tratamento endodôntico, desobturação, preparo do canal radicular e moldagem. Proteticamente, um pino intrarradicular reto e outro curvo, ambos com núcleo para sustentar a coroa metálica fundida foram cimentados na porção coronal de cada raiz-réplica. Os núcleos e coroa metálica foram ambos ferulados ou estojados. Avaliou-se os dois tipos de restauração com pino intrarradicular curvos ou retos cimentados com cimento de fosfato de zinco ou resinoso para identificar o melhor conjunto restaurador. Os testes de resistência biomecânica de 80 raízes-réplicas foram divididos em 4 grupos com 20 corpos de prova para cada um dos grupos. Grupo 1: das raízes-réplicas com pino intrarradicular curvo cimentados com cimento resinoso. Grupo 2: das raízes-réplicas com pino intrarradicular curvo cimentados com cimento de fosfato de zinco. Grupo 3: das raízes-réplicas com pino intrarradicular reto cimentados com cimento resinoso. Grupo 4: das raízes-réplicas com pino intrarradicular reto cimentados com cimento de fosfato de zinco. Estes grupos foram submetidos a teste de força com pré-carga de 1,5 N, com velocidade de avanço constante de 0,05 mm por minuto em ponto pré- determinado (mésio-lateral vestibularizada) até ocorrência de fratura do conjunto ou parte dele em uma Máquina Universal Kratos. Com a avaliação biomecânica e estudo estatístico de Kruskall-Wallis, identificou-se que os dados obtidos não seguiram distribuição normal. Esta diferença mostrou-se com o p<0,05 na interpretação do teste. No caso de dados não paramétricos o post-hoc do Kruskal-Wallis foi o teste de U de Mann-Withney. Paralelamente, um estudo com análise de elementos finitos comparou os resultados obtidos. Não houve diferença significativa sobre o tipo de cimento utilizado ou que favorecesse o uso do pino reto ou do pino curvo, recaindo a escolha para o operador decidir de acordo com a melhor indicação para cada caso clínico / The dogs, by various factors, present fractured teeth with or without pulp exposure. These fractures are basically identified as recoverable fractures not complicated, recoverable complicated or unrecoverable. Recoverable fractures (located just on enamel and dentin) are treated with restorative dentistry. The complicated recoverable (with lesions in enamel, dentin and exposure of the root canal) need to undergo endodontic treatment, and may be followed by metallic restorations. The teeth most commonly affected are the canine teeth, upper or lower. This work on artificial teeth simulating considerable destruction of their coronal portions aimed to test, after the adaptation of the cast metal restoration, the fractures in the canine teeth. Artificial teeth were standardized with an artificial root replication technique in acrylic chemically activated resin impression. Eighty equal photopolimerized composite resin replicas, standardized in size and shape, were built with this technique. Before the prosthetic reconstruction, endodontic treatment, desobturation, root canal preparation and molding were done. Protetically an intrarradicular straight pin and another curved one, both to sustain core fused metal crown were cemented over the crown of each root replica. The cores and metal crown were both belted or sheathed. It was evaluated the two types of restorations with intrarradicular curved or straight pin cemented with zinc phosphate cement or resin to identify the best restorative set. The biomechanical resistance tests applied over the 80 replica roots were divided into 4 groups with 20 samples for each of the groups. Group1: roots with intrarradicular curved pin replicas cemented with resin cement. Group 2: roots with intrarradicular curved pin replicas cemented with zinc phosphate cement. Group 3: roots intrarradicular straight pin replicas cemented with resin cement. Group 4: roots intrarradicular straight pin replicas cemented with zinc phosphate cement. These groups were submitted to the test of strength with 1.5 N preload force, with constant speed rate of 0.05 mm per minute in a predetermined point (mesio-vestibular) until occurrence of fracture of the whole set or part of it in a Universal Machine Kratos. The Biomechanical evaluation and statistical study of Kruskall-Wallis, identified that the data obtained did not follow normal distribution. That difference showed up with the p < 0.05 in the interpretation of the test. In the case of parametric data post-hoc Kruskal-Wallis test of U of Mann-Whitney. At the same time, a study with finite element analysis compared the results obtained. There was no significant difference on the type of cement used or favoring the use of straight or curved intrarradicular pin, therefore it is up to the surgeon to decide according to the best indication for each clinical case
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Valorisation des déchets de la filière « bois » en deux étapes : isolation des molécules extractibles puis fabrication de charbon actif : cas du pin maritime / Valorisation of wood wastes in two steps : isolation of extractibles molecules and production of activated carbon : case of maritime pine woodMeullemiestre, Alice 11 June 2014 (has links)
Les avancées scientifiques dans les plantes, les technologies de transformation, les biotechnologies permettent d’envisager à terme que des produits de la chimie verte du carbone renouvelable, substituables et compétitifs, remplaceront ceux issus des matières fossiles. En effet, l’un des grands thèmes de recherche actuelle en chimie est la chimie dite "propre". Dans ce cadre, le projet proposé vise une double valorisation de déchets issus de la filière "bois". La première valorisation concerne l’isolation de molécules extractibles, qui sont présentes en très faible quantité dans les matériaux lignocellulosiques, donc des produits à forte valeur ajoutée. La seconde valorisation concerne la transformation du résidu, après isolation des extractibles, en charbon actif, autre matériau à forte valeur ajoutée. Le procédé proposé concerne donc le secteur de la « chimie verte » avec une approche intégrée de « valorisation des déchets ». Nous avons utilisé comme matière première des déchets de pin maritime des Landes sous forme de sciure, à partir desquels nous avons extrait les composés volatils à partir de différents procédés intensifiés tels que les microondes et les ultrasons. L’huile obtenue a été caractérisée en déterminant sa quantité (rendement), sa composition, sa capacité antioxydante, la quantité en polyphénols qu’elle renferme, sa microstructure, etc. Afin que la valorisation de ces déchets soit totale, les résidus solides ont subi une pyro-activation physique avec du CO2 et de la vapeur d’eau comme agents activants pour produire du charbon actif. Une optimisation a été effectuée à partir des réponses suivantes : la surface BET, la taille des pores par adsorption d’azote à 77 K et les propriétés d’adsorption du charbon actif en phase aqueuse (paramètres de Langmuir et Freundlich). / The scientific advances in plants, processing technologies, biotechnology allow considering that the products of renewable carbon green chemistry, substitutable and competitive will replace the products issued from fossil material. In this framework, this project concerned a double valorization of waste from wood sector. The first valorization concerned the isolation of extractable compounds which are present in low quantities and could be considered as a high added value product. The second valorization deals with the transformation of the residue in another high added value product : the activated carbons. Thus, the proposed process concerns the sector of "green chemistry" with an integrated approach of "waste valorization". In the framework of this study, we used as raw material sawdust of maritime pine (pinus pinaster) from Landes area from an isolation of volatiles extracted by some intensified processes such as microwave and ultrasounds. The obtained oil was characterized by determining the quantity (yield), the composition, the antioxidant capacity, the polyphenols content and by studying the microstructure. To achieve a total valorization the residues were submitted to a pyro-activation with CO2 and water vapor as activating agents to produce an activated carbon. An optimization was carried out according to different responses as the BET surface, the pores size by nitrogen adsorption at 77 K and the adsorption properties of activated carbon in aqueous phase (Langmuir et Freundlich parameters).
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Metalurgie podél východoegejského a západoanatolského rozhraní ve 2. tisíciletí př. n. l. / Metallurgy along the East Aegean-West Anatolian Interface in the Second Millennium B.C.Roháček, Miloš January 2015 (has links)
(in English): This thesis aims at collecting, cataloguing and analysing bronze objects from the area of the East Aegean-West Anatolian Interface in the second millennium B.C. Based on closer typological assessment and comparanda, the question of eventual local specific production along the Interface, different from the Aegea or Eastern Mediterranean, is being investigated here. From up to 217 collected items, indeed many types of bronzes, especially swords, razors and spearheads indeed show a set of specific features. Also, the characteristic of bronze metals differs in Lower Interface with stronger minoan-mycenaen influnce from items in Upper Interface which seems to be following more anatolian features.
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Analysis of Variable Insensitive Friction Stir Welding ParametersMarrero, Robert L, Jr 09 August 2017 (has links)
Friction Stir Welding (FSW) was used to perform a Design of Experiment (DOE) to determine the welding parameters effects on yielding consistent mechanical properties across the length of the weld. The travel speed was varied across set forge force and RPM conditions, to find a dataset that will yield consistent mechanical properties independent of the travel speed. Six different welds were completed on two different aluminum panels, the advancing side being Aluminum alloy 2195-T8 at a thickness of .350”, with the retreating side being Aluminum alloy 2219-T851 with a gauge thickness of .360”. A Left-hand Right-hand self-reacting pin tool was used for each weld. The mechanical properties of interest are the Ultimate Tensile Strength, Yield Strength, Elasticity and Hardness. The strengths were evaluated by tensile testing, with the Elasticity being measure post break. Specimens were then polished where macrograph and micrograph analysis was completed. Micro-hardness testing was then completed on the weld nuggets.
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Influence of Alumina Addition to Aluminum Fins for Compact Heat Exchangers Produced by Cold Spray Additive ManufacturingFarjam, Aslan January 2015 (has links)
Aluminum and aluminum-alumina powder mixtures were used to produce pyramidal fin arrays on aluminum substrates using cold spray as an additive manufacturing process. Using aluminum-alumina mixtures instead of pure aluminum powder could be seen as a cost-effective measure, preventing nozzle clogging. The fin geometries that were produced were observed using a 3D digital microscope to determine the flow passages width and fins geometric details. Heat transfer and pressure tests were carried out using different ranges of appropriate Reynolds numbers for the sought commercial application to compare each fin array and determine the effect of alumina content. It was found that the presence of alumina reduces the fins’ performance when compared to pure aluminum but that they still outperform traditional fins. Numerical simulations were performed and were used to explain the obtained experimental results. The numerical model opens up new avenues in predicting different parameters such as pressure and substrate temperature.
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Étude des mécanismes de rétention du récepteur opioïde deltaSt-Louis, Etienne January 2016 (has links)
Les médicaments de type opioïde représentent la classe de médicaments la plus utilisée pour les douleurs modérées à sévères. C’est pour cette raison que les opioïdes et leurs récepteurs sont très étudiés et qu’il y a beaucoup de publications sur ces récepteurs. En revanche, peu d’études ont cherché à identifier les partenaires d’interactions de ces récepteurs puis à comprendre les mécanismes d’adressage à la membrane.
Même si le récepteur opioïde delta (DOPr) n’est pas encore ciblé en clinique, beaucoup d’équipes s’intéressent à son rôle et à l’effet d’agonistes DOPr dans le but de trouver une nouvelle avenue thérapeutique contre la douleur. Cependant, en condition normale, les agonistes DOPr ont un faible potentiel analgésique, expliqué par le faible niveau de DOPr à la surface cellulaire des neurones. C’est pourquoi il est important de comprendre son adressage à la membrane afin de combiner les traitements aux agonistes DOPr à une thérapie qui augmenterait l’expression de surface du récepteur. De plus, on sait qu’il existe un mécanisme de régulation de l’adressage de DOPr à la surface mais il reste peu compris. Nous avons donc analysé par spectrométrie de masse le complexe protéique résultant de l’immunoprécipitation de FlagDOPr, surexprimé dans des cellules HEK293, afin d’identifier de nouveaux partenaires d’interaction. Dans cette analyse, plusieurs protéines appartenant au complexe vésiculaire COPI ont été identifiées. Nous avons montré dans l’article que DOPr interagit avec COPI via les domaines intracellulaires 2 et 3 et que ces sites d’interaction sont responsables de la rétention de DOPr. De plus, mes travaux se sont penchés sur la régulation de DOPr à la surface cellulaire, telle que l’interaction DOPr avec les protéines cdk5 et pin1, deux protéines pouvant faire partie d’un mécanisme impliqué dans la régulation du transport de DOPr à la surface cellulaire.
Comprendre l’export de DOPr est important pour le développement de nouvelles thérapies contre la douleur et plusieurs théories ont été abordées dans le cadre de mes travaux de maîtrise.
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Contraction heat transfer coefficient correlation for rectangular pin fin heat sinksSchmitt, Stephan 11 July 2011 (has links)
The demand for smaller but more powerful electronic components is ever increasing. This demand puts a strain on engineers to produce optimal cooling designs for these electronic components. One method for cooling these electronic components is with heat sinks which effectively increase the surface area available for extracting the heat from the electronic components. Computational Fluid Dynamics (CFD) software is sometimes used to aid in the design process, but CFD simulations are computationally expensive and take long to complete. This causes the design engineer to test only a few proposed designs based on his/her experience and select the design that performs the best out of the tested designs, which might not be the optimum. The temperature distribution inside the heat sink can be solved relatively quickly with the diffusion equation, but the flow around the heat sink complicates the CFD simulation and increases the solving time significantly. Therefore, applications have been developed where the interaction between the heat sink and the flow around the heat sink is replaced by heat transfer coefficients. These coefficients are calculated from correlated equations which contain the flow properties. The flow properties are extracted from a flow network solver, which solves the flow around the heat sink. This procedure results in less expensive simulations, which can be used together with an optimisation procedure to develop an optimum cooling design. In this dissertation, a correlation for the contraction heat transfer coefficients of rectangular pin fin heat sinks was developed. A methodology was developed where consecutive regression lines were fitted to a large set of data extracted from numerous CFD simulations. The combination of these regression lines formed the basis of the correlation, which was divided into two correlations; one for laminar flow and another for turbulent flow. The correlations were tested against CFD simulations as well as experimental data. The results indicate that these correlations can be effectively used to calculate the contraction heat transfer coefficients on pin fin heat sinks. / Dissertation (MEng)--University of Pretoria, 2011. / Mechanical and Aeronautical Engineering / unrestricted
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Estudo do desgaste de nanocompósitos de alumina-zircônia usando variação de parâmetros no ensaio pino-no-disco / Wear study of alumina-zirconia nanocomposites using variation of parameters in the pin-in-disk testGomez, Ana Carolina 23 October 2017 (has links)
O desgaste é responsável por um grande número de falhas em materiais, provocando a sua substituição antecipada e consequentemente diminuindo a sua vida útil. Por isso, estudos são realizados para caracterizar os limites de utilização desses materiais, evitando assim situações catastróficas. A partir das variáveis e parâmetros envolvidos no ensaio de desgaste, é possível construir mapas que tem como finalidade direcionar para uma correta escolha do material, de acordo com a aplicação desejada, além de identificar o seu comportamento frente à determinadas condições de uso. Neste contexto, este trabalho teve como objetivo conhecer o comportamento de desgaste de nanocompósitos de alumina contendo 5% de inclusões nanométricas de zircônia, visando construir um diagrama de transição de desgaste entre os limites de combinação de velocidade de deslizamento e carga aplicada. Para isso, corpos de prova conformados na forma de pinos com uma das extremidades semiesféricas foram caracterizados quanto a dureza e tenacidade à fratura, submetidos ao ensaio de desgaste do tipo pino-no-disco com temperaturas e umidades ambientes, variando os parâmetros de velocidade e carga. As velocidades de deslizamento variaram de 1,2 m/s à 0,1 m/s e as cargas variaram de 2 N à 100 N. Os valores de dureza e tenacidade a fratura obtidos foram de 14,08 ± 1,22 GPa e 3,99 ± 0,14 MPa.m1/2, respectivamente. Os resultados de desgaste mostraram que a partir da caracterização e construção do diagrama de transição de regime de desgaste, com combinações de parâmetros extrínsecos de carga e velocidade de deslizamento, foi possível definir e atingir as condições limites entre o regime de desgaste moderado e a transição para o regime severo. Esse diagrama auxilia na seleção e comparação da transição entre os limites de desgaste do material estudado com outros tipos usados na engenharia. / Wear is responsible for a large number of material failures, causing them to be replaced early and consequently shortening their life-time. Therefore, studies are conducted to characterize the limits of use of these materials, thus avoiding catastrophic situations. From the variables and parameters involved in the wear test, it is possible to construct maps that aim to direct the correct choice of material according to the desired application, as well as to identify its behavior against certain conditions of use. In this context, the objective of this work was to know the wear behavior of alumina nanocomposites containing 5% nanometric zirconia inclusions in order to construct a simplified wear transition diagram between the sliding speed and applied load combination limits. For this, test pieces shaped like pins with semi-spherical tips were characterized in terms of hardness and fracture toughness, took to the wear test of the pin-on-disk with ambient temperatures and humidity, varying the speed and load parameters. Slip velocities ranged from 1.2 m/s to 0.1 m/s and loads ranged from 2 N to 100 N. The values of hardness and fracture toughness obtained were 14.08 ± 1.22 GPa and 3.99 ± 0.14 MPa.m1/2, respectively. The results of wear showed that from the characterization and construction of the wear regime transition diagram, with combinations of extrinsic load parameters and slip speed, it was possible to define and reach the boundary conditions between the moderate wear regime and the transition for the severe regime. This diagram helps in the selection and comparison of the transition between the wear limits of the studied material with other types used in engineering.
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