Transition metal carbides have great industrial importance with a wide area of applications. Unlike many ceramic materials which can be produced from raw materials found in nature, the refractory carbides generally do not exist in the natural state. Synthesis of these carbides is costly and exacting. Sputtered coatings of the refractory metal carbides are of great interest for applications where hard wear-resistant materials are desired. Understanding how the experimental conditions affect the microstructure and properties in reactive sputtering deposition process is still an area of intense research activity. Reactively sputtered zirconium carbide thin films were grown on (100) silicon substrate and the influence of substrate temperature on the properties of the films were investigated. The substrate temperature was varied from ambient to 500°C and partial pressures of the sputter gas and reactive gas (argon and methane) were optimised to obtain crystalline films. Structural characteristics showed that the films exhibit nanocomposite structure consisting of ZrC nanocrystallites embedded in amorphous carbon typically at lower growth temperature (TS < 300°C), and at higher growth temperatures film were highly textured. In addition, Films deposited at 325 °C showed a distinct increase in FWHM which had considerable effect on the mechanical properties of the film. Maximum hardness of 24.8 GPa was seen at 325ºC. The changes in atomic bonding structures, their relative fractions with respect to substrate temperature were discussed. We also report superhard nanocrystalline nanocomposite NbC thin film deposited on Si (100) under 500˚C growth temperature via reactive magnetron sputtering. The pronounced nano hardness and modulus value of 42 GPa and 267 GPa at 40/60 C/Nb ratio were found to be strongly dependent on the grain size and higher percentage of carbide content. HRTEM studies further confirm the formation of nanocomposite structure with nanocrystalline grains embedded in amorphous matrix. The influence of vapour incidence angle (α= 0˚ to 75˚) on optimized ZrC and NbC thin films were investigated by depositing films in Oblique angle deposition geometry (OAD). The anisotropic growth rate of crystallographic planes and the mechanism of development of micro structural features in OAD of carbide films have been investigated. XRD and pole figure measurements indicated that the films grown at higher growth temperatures (800°C) exhibited higher degree of preferred orientation coupled with larger crystallite size whereas the films deposited at room temperature displayed random polycrystalline nature. The strong increase in porosity with increase in deposition angle with distinctly separated nanometer sized columns resulted in lowering of hardness and reduced modulus value. The film with zero incidence angle exhibited a maximum hardness and reduced modulus of 28 GPa and 223 GPa respectively. On the other hand, NbC films deposited with OAD, remained to be polycrystalline in nature with less intense peaks and also exhibited loss of preferential orientation indicating lower crystal quality with increase in vapor deposition angle. It is apparent that variation in crystallographic texture coupled with sculptured nanostructures are solely material dependent properties. Nano metric modulated ZrC/NbC superlattice multilayer structure performance has been evaluated for structural stability and hardness enhancement. Multilayers present superlattice effect in XRD patterns, which are attributed to the precise periodical stacking of crystalline monolayers also confirmed by cross section FESEM. X-ray photoelectron spectroscopy depth profile analysis was performed to get information on chemical composition of modulated layers and also to get an insight on the interface region. Hardness and modulus value of 43.2 GPa and 272 GPa was observed which is higher than individual monolayers response to mechanical loading. The enhanced hardness is possibly due to the inhibition of dislocation motion along the interface and also due to strain effects at the interface.

Utilizou-se o conceito de ?aço matriz + NbC? para produzir ligas com a matriz do aço rápido M2 ( 0,5%C ? 2%W ? 3%Mo ? 4,6%Cr ? 1%V) e variadas frações volumétricas de carbonetos de nióbio. Adicionou-se 2,5 e 5% de nióbio e carbono estequiométrico para a obtenção de carbonetos NbC e titânio (0,1%) para modificação da morfologia dos carbonetos NbC. Os carbonetos NbC apresentaram-se como carbonetos eutéticos com morfologia de escrita chinesa, como carbonetos primários com a morfologia de cruz de malta e como carbonetos eutéticos e primários com morfologia poligonal, estes últimos modificados com a adição de titânio. Após tratamento térmico de têmpera e revenimento para obtenção da máxima dureza, as ligas foram submetidas a ensaios de fadiga térmica (100 ciclos, 650ºC), de abrasão (roda de borracha ? 130N, 200rpm, 30min, hematita como abrasivo) e de deslizamento alternado (disco contra esfera ? 70,6N, amplitude: 6mm, freqüência, 6 Hz, 2h) para estudar o efeito da fração volumétrica e da morfologia dos carbonetos frente a estas solicitações. As ligas com carbonetos com morfologia poligonal e menor fração volumétrica de carbonetos (comparando-se morfologias iguais) apresentaram o melhor desempenho sob fadiga térmica devido ao baixo valor do parâmetro C/Dm da microestrutura (continuidade de carbonetos/distância livre média entre carbonetos). Os corpos-de-prova foram caracterizados por meio de microscopia ótica e eletrônica de varredura para determinar os sítios de nucleação e caminhos de propagação das trincas. Nos ensaios em roda de borracha as ligas com carbonetos eutéticos divorciados com morfologia poligonal apresentaram maior resistência ao desgaste do que os aços contendo carbonetos eutéticos cooperativos. O aumento da fração volumétrica de carbonetos NbC teve um máximo na resistência a abrasão e depois uma queda devido a presença de carbonetos primários grosseiros que fraturaram na superfície ensaiada e foram arrancados aumentanto a perda de massa. Nos ensaios de deslizamento alternado não foi possível hierarquizar o comportamento das ligas. Os corpos-de-prova de abrasão e de deslizamento foram caracterizados por microscopia ótica e eletrônica de varredura para determinar os mecanismos de desgaste atuantes. Um aço rápido para cilindros de laminação a quente (2%C ? 5%Cr ? 5%Mo ? 5%V) foi ensaiado sob condições idênticas às aplicadas às ligas estudadas, objetivando comparar desempenhos. O aço rápido apresentou desempenho superior nos ensaios de abrasão e de deslizamento alternado (devido a alta fração volumétrica de carbonetos eutéticos) e inferior no ensaio de fadiga térmica (devido ao alto parâmetro C/Dm da microestrutura oriundo da alta fração volumétrica de carbonetos eutéticos). / The concept of ?matrix steel + NbC? was used to cast alloys with the M2 steel matrix (0,5%C ? 2%W ? 3%Mo ? 4,6%Cr ? 1%V) and different volume fractions of niobium carbides. Niobium (2,5 e 5%) and stoichiometric carbon were added to produce NbC carbides and titanium (0,1%) to modify de NbC carbides morphology. NbC presented three basic morphologies: Chinese script (coupled eutectic); primary carbides with cross morphology and polygonal primary and eutectic carbides (divorced eutectics). After heat treatment of quench and temper in order to obtain the maximum hardness, the alloys were submitted to thermal fatigue test (100 cycles, 650ºC), dry rubber wheel abrasive wear test (130N, 200rpm, 30min, hematite as abrasive) and reciprocating sliding wear test (70,6N, amplitude: 6mm, frequency: 6Hz, 2h). The alloys with polygonal NbC carbides and lower volume fractions of carbides (for the same morphology) showed the best behaviour due to their low ?carbide continuity/carbide free path? ratio of the microstructure. The alloys were characterized by optical microscopy and SEM to investigate de cracks nucleation and propagation. In the dry rubber wheel tests, polygonal NbC eutectic carbides (divorced eutectics) showed better behaviour than Chinese script NbC eutectic carbides. High volume fractions of NbC carbides improved the abrasion resistance until a maximum and after that, the presence of big primary NbC carbides, lowered the abrasion resistance due to cracks in those big carbides. The results of the reciprocating sliding tests have not allowed to rank the performance of the alloys. Abrasion and sliding specimens were submitted to optical microscopy and SEM in order to evaluate the prevalent wear mechanisms. One high speed steel for hot rolling mill rolls (2%C ? 5%Cr ? 5%Mo ? 5%V) was tested under the same conditions that the alloys studied were tested in order to compare their performances. The high speed steel showed better performance in abrasion and reciprocating sliding wear due to the high volume fraction of coupled eutectic carbides and lower performance in thermal fatigue due to the high ?carbide continuity/carbide free path? ratio of the microstructure than the alloys studied.

Les alliages de type HP constituent un matériau de choix pour l'élaboration des tubes de vaporeformage et de vapocraquage dans l'industrie pétrochimique. Exposés à des températures comprises entre 700°C et 1000°C sous des pressions gazeuses de plusieurs MPa, leur microstructure initiale associée à une fine précipitation secondaire, intervenant en cours de service, leur confèrent une excellente résistance aux mécanismes de fluage auxquels ils sont sujets. Néanmoins, à terme, la coalescence des précipités conduit à la dégradation rapide des tubes.Les effets de certains éléments d'alliages (V, Ti/W) sur la précipitation secondaire des carbures M23C6 et NbC ont été étudiés au travers de simulations via le logiciel TC-PRISMA. Sur la base de résultats prometteurs en termes d'optimisation des caractéristiques de la précipitation, deux alliages modèles ont été coulés au laboratoire et soumis à divers vieillissements dans la gamme de température correspondant aux conditions de service. Les microstructures de ces alliages ont d'abord été comparées à celle d'un alliage HP industriel de composition standard à l'état brut de coulée. La précipitation secondaire a par la suite été caractérisée au sein des trois alliages dans les différents états vieillis. Les investigations microstructurales ont permis de mettre en avant certains effets bénéfiques d'un ajout de vanadium et d'ajouts combinés de titane et de tungstène sur les caractéristiques de la précipitation secondaire. / HP alloys are typically used as steam methane reforming tubes in the petrochemical industry. During service, they are exposed to temperatures between 700°C and 1000°C under gaz pressure of several MPa. Their as-cast microstructure, together with fine in-situ secondary precipitation, provide these alloys with an excellent resistance to creep deformation. Nevertheless, after long-time ageing, coarsening of secondary carbides leads to the weakening of the tubes and therefore to an accelerated damaging.The effects of some alloying elements (V, Ti/W) on secondary precipitation of M23C6 and NbC carbides were investigated through numerical simulations performed with TC-PRISMA software. On the basis of encouraging results in terms of precipitation optimization, two model HP-type alloys were cast at the laboratory and aged in the range of temperatures corresponding to service conditions. As-cast microstructures were first compared with an industrial "standard" alloy. Then, secondary precipitation were characterized for all the alloys and all ageing temperatures. Microstructural investigation highlighted the beneficial effect of vanadium and titanium/tungsten additions on secondary precipitation characteristics.

NBC?s situation comedy The Office reflects on the nature of workplace management in the 21st century. The show critiques a corporation that values conformity over individuality, while implying that promoting ?creative? employees to upper management is not credible alternative. The Office does this by focusing on Michael Scott (played by Steve Carell), a character whose unique creative working style makes him a great salesman but a poor manager. Michael?s character stands in contrast to Ryan Howard (played by B.J. Novak), who differs from Michael both in his approach to business and his success at it. The Office implies that creativity is a valuable asset for non-managerial workers, but creative management can be problematic. As workplaces continue to evolve, it is imperative to explore how creativity and bureaucracy co-exist. It may be unrealistic to expect creativity to saturate all aspects of professional life, but striking a balance between creativity and organization might be paramount in assuring job satisfaction and productivity for future generations of employees.

Autism has been declared an urgent public health concern by the U.S. government and an epidemic by some advocacy groups. Determining autism’s diagnostic criteria, prevalence, and causes have been challenging. It is important to examine how the U.S. media have contributed to the public’s understanding of autism. Previous research found that British media coverage of the theory that vaccines cause autism was shown to contribute to the decline of vaccination rates in Britain (Lewis & Speers, 2003). This study examined U.S. television news media coverage using an agenda-setting theory and media framing perspective. A content analysis was conducted of national television evening news broadcasts airing on ABC, CBS, and NBC from 1994, when autism was first recognized as a spectrum disorder through April 2010, the time of this study. Specifically, this study examined the saliency of autism stories and how autism was framed in terms of prevalence and causes.

Thesis (M.S.)--Butler University, 1995. / Includes bibliographical references (leaves x-xiii).

Thesis (Ph. D.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 383-401). Also available online in ProQuest, free to University of Oregon users.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-02-21T21:32:47Z No. of bitstreams: 1 RicardoCesarDaSilvaRocha_TESE.pdf: 5309449 bytes, checksum: d6c6f63a7d0c3dd4a1a227198be68cee (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-02-23T18:57:37Z (GMT) No. of bitstreams: 1 RicardoCesarDaSilvaRocha_TESE.pdf: 5309449 bytes, checksum: d6c6f63a7d0c3dd4a1a227198be68cee (MD5) / Made available in DSpace on 2018-02-23T18:57:37Z (GMT). No. of bitstreams: 1 RicardoCesarDaSilvaRocha_TESE.pdf: 5309449 bytes, checksum: d6c6f63a7d0c3dd4a1a227198be68cee (MD5) Previous issue date: 2017-07-31 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Os processos de aspers?es t?rmica s?o utilizados para obten??o de revestimentos, com o objetivo, de reduzir o desgaste, minimizar os efeitos da corros?o ou para reparo de superf?cies, com aplica??es na ind?stria de petr?leo, aeroespacial e el?trica, dentre outras. O carbeto de ni?bio (NbC) tem se destacado na ind?stria mec?nica, na ?rea qu?mica e de microeletr?nica, por apresentar propriedades como elevada dureza, alto ponto de fus?o (3610?C), elevada condutividade t?rmica, grande estabilidade qu?mica, al?m de resist?ncia a radia??o. As propriedades dos revestimentos dependem da composi??o qu?mica e da microestrutura, que s?o influenciadas por sua vez pelos par?metros do processo. A t?cnica de deposi??o atrav?s de tocha de plasma por arco n?o transferido vem sendo estudada para o processamento de revestimentos. O Fe-NbC ? um novo produto desenvolvido para ser utilizado como refor?o por proporcionar melhoria nas propriedades mec?nicas de materiais met?licos. Apresenta-se neste trabalho os resultados de uma investiga??o sobre a forma??o, caracteriza??o e desempenho tribol?gico de camadas duras, obtidas por aspers?o t?rmica atrav?s de plasma de arco n?o transferido a partir de p?s de Fe-NbC, depositados em substrato de a?o ABNT 1020. Para a obten??o das camadas, foram variadas a corrente de trabalho e a vaz?o de g?s da tocha. Os revestimentos obtidos foram caracterizados por meio de an?lises de difra??o de Raios X, microscopia ?ptica, microscopia eletr?nica de varredura, an?lise qu?mica, rugosidade, microdureza Vickers e testes de pino sobre disco. Os resultados indicaram que as varia??es dos par?metros de deposi??o alteraram a dureza e o coeficiente de atrito devido a forma??o de fases de NbC e Fe3O4. / Thermal spraying processes are used to obtain coatings, which can reduce erosion, minimizing the effects of corrosion or for repairing surfaces, with applications in the petroleum, aerospace and electrical industries, among others. NbC carbide has been outstanding in the mechanical, chemical and microelectronic industries since it has properties such as high hardness, high melting point (3610 ? C), high thermal conductivity, high chemical stability, besides resistance to radiation. The properties of the coatings depend on the chemical composition and the microstructure, which are influenced by the process parameters. The technique of deposition through an untransferred arc plasma torch has been studied for coating processing. Fe-NbC is a new product developed to be used as reinforcement because it provides improvement in the mechanical properties of metallic materials. This work presents the results of an investigation on the formation, characterization and tribological performance of hard layers obtained by thermal spraying, using non-transferred arc plasma from Fe-NbC powders deposited on ABNT 1020 steel substrate. To get the layers, the working current and the gas flow of the torch were varied. The obtained coatings were characterized by X-ray diffraction analysis, optical microscopy, scanning electron microscopy, chemical analysis, roughness, Vickers microhardness and pin-to-disk tests. The results indicated that the variations of the deposition parameters have changed the hardness and the coefficient of friction due to the formation of NbC and Fe3O4 phases.

Submitted by Suethene Souza (suethene.souza@ufpe.br) on 2015-03-09T17:30:33Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO Marco Antonio Granha.pdf: 1263356 bytes, checksum: 9dc72d1fa8943f95af039a3ad5c365bd (MD5) / Made available in DSpace on 2015-03-09T17:30:33Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) DISSERTAÇÃO Marco Antonio Granha.pdf: 1263356 bytes, checksum: 9dc72d1fa8943f95af039a3ad5c365bd (MD5) Previous issue date: 2014-04-30 / O presente estudo teve como objetivo explicar como as empresas de serviços contábeis se adaptaram a NBC TG 1000 – Contabilidade para Pequenas e Médias Empresas para a preparação, elaboração e divulgação das demonstrações contábeis de seus clientes. Para alcançar esse objetivo, a pesquisa utilizou uma abordagem de métodos misto sequencial, sendo inicialmente aplicado um questionário de pesquisa para as 148 empresas de serviços contábeis associadas ao SESCAP-PE obtendo 35 respostas representando a etapa quantitativa do estudo. Em seguida, entrevistas semiestruturadas baseadas em um roteiro elaborado a partir dos resultados da etapa inicial, foram realizadas com 8 sócios de 7 empresas de serviços contábeis de reconhecida experiência e competência técnica, representando a etapa qualitativa do estudo. Os resultados da etapa inicial da pesquisa evidenciaram que a maioria das empresas pesquisadas não adotam plenamente ou não conhecem a norma. Na segunda etapa da pesquisa, onde se buscou o aprofundamento das questões apontadas na etapa inicial, os resultados revelaram que a adoção da NBC TG 1000 pelas empresas de serviços contábeis ocorreu de forma parcial, sendo utilizadas apenas as seções relativas a elaboração das demonstrações contábeis. Os principais fatores que dificultaram a adoção plena da norma evidenciados pela pesquisa foram: a complexidade do texto do pronunciamento e o prazo considerado muito curto entre a divulgação e sua obrigatoriedade de adoção, a necessidade de cumprimento das exigências fiscais, o conhecimento ainda em fase de consolidação dos profissionais da contabilidade, a falta de interesse e conhecimento dos clientes em relação a importância das demonstrações contábeis e a resistência para entrega das informações e documentações em tempo hábil para o registro tempestivo das transações. Embora os respondentes tenham adotado de forma parcial a norma, todos consideram positivo o processo de convergência ao padrão internacional de contabilidade.

Submitted by Natalia de Souza Gonçalves (natalia.goncalves@ufpe.br) on 2016-09-19T14:23:00Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Atualizada_Dissertação Yuri Prestes 2016 PPGO l.pdf: 5509758 bytes, checksum: 8f72293dc72621c1a2af7560c8875b2a (MD5) / Made available in DSpace on 2016-09-19T14:23:01Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Atualizada_Dissertação Yuri Prestes 2016 PPGO l.pdf: 5509758 bytes, checksum: 8f72293dc72621c1a2af7560c8875b2a (MD5) Previous issue date: 2016-02-19 / Este trabalho tem foco em processos físicos oceanográficos que dominam a interação entre o estuário do Rio Pará e a Plataforma Continental Amazônica (PCA). Esta, amplamente estudada pela comunidade científica por diversas áreas do conhecimento, comumente atrelada à influência do Rio Amazonas sobre a plataforma continental e/ou às correntes oceânicas de contorno oeste que atuam nessa região do Oceano Atlântico tropical. Contudo, uma importante questão ainda não respondida é qual a influência do estuário do Rio Pará sobre a PCA? O objetivo do presente trabalho é analisar a interação das forçantes físicas dentro do sistema Rio Pará-PCA. Medições eulerianas na plataforma e no estuário foram realizadas de modo a abranger as variabilidades temporais da área de estudo. Na plataforma, a coleta de dados ocorreu de Abril à Julho de 2008, período que abrange a diminuição da descarga fluvial, mudanças na direção dos alísios e intensificação da Corrente Norte do Brasil (CNB). No estuário, os levantamentos realizados ocorreram ao longo de um ciclo completo de maré semidiurno, durante o período seco (Outubro 2014) e o período chuvoso (Junho 2015) da região amazônica. Também foi elaborado um modelo em caixa (box model) de descarga para estivar a magnitude do aporte fluvial do Rio Pará. A propagação da onda de maré domina o sistema, gerando fluxos bidirecionais em regiões de micromaré a mais de 300 km de distância da foz do estuário. Na PCA, a maré gera intensas correntes barotrópicas no sentido da componente de velocidade transversal à plataforma, até alcançar a foz do sistema estuarino. Na quebra da plataforma, no período em que a CNB se intensifica, suas bordas de corrente atingem a PCA em profundidades < 100 m, agindo como um importante mecanismo nas trocas entre a plataforma amazônica e o oceano profundo do Atlântico Tropical. A magnitude da descarga média estimada pelo box model foi de 2 x 104 m3s-1, demonstrando também que o maior contribuinte hídrico para o Rio Pará é o Rio Tocantins. A força de empuxo gerada pela descarga fluvial interage com a força da maré, produzindo variabilidade lateral no estuário do Rio Pará. Na margem direita, há tendência de fluxos laminares, estratificação vertical e correntes baroclínicas, com processos mistura principalmente por difusão. Entre tanto, na margem esquerda, foi verificado a presença de fluxos turbulentos, ausência de gradientes de densidade vertical e correntes barotrópicas, de modo que os processos de mistura por advecção dominam a mistura no sistema. Os resultados apresentados ao longo de três artigos científicos enfatizaram o quão complexo e dinâmico é o sistema Rio Pará-PCA. Esta característica dinâmica do sistema gera a extrema necessidade de que as atividades potencialmente danosas devem ser desenvolvidas juntamente com medidas de prevenção para evitar danos ao meio ambiente. / This work aims to study on oceanographic physical process that dominate the interaction between the Pará River estuary and Amazon Continental Shelf (ACS). This widely studied by the scientific community in various areas of geosciences, commonly associated to Amazon River influence on the continental shelf, or to boundary ocean currents which occur in western of Atlantic Tropical. However, an important question not answered yet, is the influence of Para River estuary on the ACS? The objective of this study is to analyze the interaction of physical forcings within the Pará River-ACS system. Eulerian measurements on the platform and in the estuary were carried out to cover the temporal variability of the study area. On the amazon shelf, data collection occurred from period of April to July 2008 covering the decrease in river discharge, changes in the direction of the trade and intensification of the North Brazil Current (NBC). In the estuary, the surveys occur over a full semidiurnal tidal cycle during the amazonian dry season (October 2014) and the rainy season (June 2015). It was also prepared a discharge box model to estimate the magnitude of fluvial contribution of Pará River on the ACS. The tidal wave propagation dominates the system, generating bidirecional flows in microtides regions more than 300 km away from the estuary mouth. In the ACS, the tides creates intense barotropic currents towards the across-shelf velocity component until reach the mouth of the estuary system. On the shelf break, in the period in which the CNB intensifies, its current edges reach the ACS at < 100 depth, acting as an important mechanism in the exchange process between the Amazon shelf and the deep ocean of the Atlantic Tropical. The estimated of average discharge magnitude by box model was 2 x 104 m3s-1, also showing that the largest input to the Pará River is the Tocantins River. The buoyancy force generated by river discharge interacts with the tidal force, producing lateral variability in the estuary of Para River. On the right margin, there is a tendency of laminar flow, vertical stratification and baroclinic currents, with mixing processes primarily forced by diffusion. Meanwhile, the left margin, it was verified the presence of turbulent flow, no vertical density gradients, and intense barotropic currents, so that the advection processes dominate the mixing in the system. The results presented over the three papers emphasize how complex and dynamic is the Pará river-ACS system. This dynamic characteristic generates extreme need for potentially damaging activities should be developed together with preventive measures to avoid damage to the environment.