Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-10-10T14:30:31Z No. of bitstreams: 1 2015 - Alessandra de Lima Machado.pdf: 1487065 bytes, checksum: cd9c7f300bf5103dbe9de9f9244f7bbb (MD5) / Made available in DSpace on 2017-10-10T14:30:33Z (GMT). No. of bitstreams: 1 2015 - Alessandra de Lima Machado.pdf: 1487065 bytes, checksum: cd9c7f300bf5103dbe9de9f9244f7bbb (MD5) Previous issue date: 2015-02-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The evaluation of toxicity caused by aluminum (Al) trees used in urban forestry is of great importance for the development of seedlings and plantings in appropriate conditions. The tree species Bauhinia variegata L. is commonly used in urban afforestation, requiring knowledge of their nutritional requirements and conflicts related to the presence of trees on the streets, for example, interference in the electricity distribution networks. Pruning is the main practice management done on trees planted in the streets. Optimizing the pruning process can generate benefits such as less frequent pruning, lower cost and higher efficiency, especially for the energy sector. The objectives of this study were to evaluate the influence of Al in the development of Bauhinia variegata seedlings, and analyze the effectiveness of different types of pruning cut with or without the use of Al, in order to reduce shoots. This study was developed in two stages, resulting in two chapters. The first, directly related to mineral nutrition, with the study aimed to investigate the effects of Al toxicity on growth and root development. Experiments were performed in simple and complete nutrient solution and in acid soil substrate. The second chapter presents the study to assess the effectiveness of different types of pruning cut made in adult plants of Bauhinia variegata, with and without the use of Al as a growth inhibitor. The results indicated that this species is sensitive to the toxicity of Al from the concentration of 50 ?M, being observed decrease in root growth rate and relative root elongation. The critical dose to paralyze Al root growth were 151,48 ?M of Al in simple nutrient solution and 388,72 ?M of Al in complete nutrient solution. Al caused increase in the diameter of the roots of seedlings from the concentration at 400 ?M solution. The application of limestone in acid soil favored the growth of plants of Bauhinia variegata, resulting in higher dry matter weight values of root and shoot dry mass weight. When pruning was held close to the trunk and Al application shoots were not observed until the last evaluation at 210 days after pruning. In pruning held close to the trunk without Al application occurred shoots. In the cuttings leaving stump 20 and 40 cm, with or without the application of Al occurred shoots / A avalia??o da toxidez causada pelo alum?nio (Al) em ?rvores utilizadas na arboriza??o urbana ? de grande import?ncia para o desenvolvimento de mudas e plantios em condi??es adequadas. A esp?cie arb?rea Bauhinia variegata L., ? comumente utilizada na arboriza??o de urbana, sendo necess?rio o conhecimento das suas exig?ncias nutricionais e dos conflitos relacionados ? presen?a das ?rvores nas ruas, como, por exemplo, a interfer?ncia nas redes de distribui??o de energia el?trica. A poda ? a principal pr?tica de manejo realizada nas ?rvores plantadas nas ruas. A otimiza??o do processo de podas pode gerar benef?cios como menor frequ?ncia de podas, menor custo e maior efici?ncia, especialmente para o setor el?trico. Os objetivos deste trabalho foram avaliar a influ?ncia do Al no desenvolvimento de mudas de Bauhinia variegata, e analisar a efici?ncia de diferentes tipos de corte em poda associado ou n?o ao uso de Al, de modo a diminuir brota??es. Estes estudos foram desenvolvidos em duas etapas, resultando assim em dois cap?tulos. O primeiro, relacionado diretamente ? nutri??o mineral, com o estudo direcionado ? investiga??o dos efeitos da toxidez do Al no crescimento e desenvolvimento de ra?zes. Foram realizados experimentos em solu??o nutritiva simples e completa e em substrato de solo ?cido. O segundo cap?tulo apresenta o estudo de avalia??o da efici?ncia de diferentes tipos de corte em podas realizadas em plantas adultas de Bauhinia variegata, com e sem a utiliza??o de Al como inibidor de crescimento. Os resultados indicaram que esta esp?cie ? sens?vel ? toxidez do Al a partir da concentra??o de 50 ?M, sendo observada diminui??o na taxa de crescimento radicular e na elonga??o radicular relativa. As doses cr?tica de Al que paralisaria o crescimento radicular foram de 151,48 ?M de Al em solu??o nutritiva simples e de 388,72 ?M de Al em solu??o nutritiva completa. O Al provocou aumento do di?metro das ra?zes de mudas a partir da concentra??o em solu??o de 400 ?M. A aplica??o de calc?rio em solo ?cido favoreceu o crescimento de plantas de Bauhinia variegata, resultando em maiores valores de peso de massa seca de raiz e peso de massa seca de parte a?rea. Quando a poda foi realizada rente ao tronco principal e com aplica??o de Al n?o foram observadas brota??es at? a ?ltima avalia??o, aos 210 dias ap?s a poda. Na poda realizada rente ao tronco principal sem aplica??o de Al ocorreram brota??es. Nas podas deixando toco de 20 e 40 cm, com ou sem aplica??o de Al, ocorreram brota??es.

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 2016-05-07T00:01:05Z No. of bitstreams: 1 PedroHenriqueSalesDaCosta_DISSERT.pdf: 3167327 bytes, checksum: e3758236165e8d3906f6f8f92e8a236b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-05-09T20:11:14Z (GMT) No. of bitstreams: 1 PedroHenriqueSalesDaCosta_DISSERT.pdf: 3167327 bytes, checksum: e3758236165e8d3906f6f8f92e8a236b (MD5) / Made available in DSpace on 2016-05-09T20:11:14Z (GMT). No. of bitstreams: 1 PedroHenriqueSalesDaCosta_DISSERT.pdf: 3167327 bytes, checksum: e3758236165e8d3906f6f8f92e8a236b (MD5) Previous issue date: 2015-08-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Em muitos casos o passe de raiz ? uma etapa cr?tica da soldagem, uma vez que sua execu??o ? afetada por diversos fatores, tais como varia??o da abertura da junta, ?ngulo do chanfro, dimens?es da face (nariz) da raiz, inclina??o da tocha, velocidade de soldagem e velocidade de alimenta??o. Al?m disso, a escolha do processo de soldagem ? um fator primordial para garantir a execu??o de um passe de raiz com adequadas propriedades mec?nicas e metal?rgicas. Nesse contexto, este trabalho teve como objetivo estudar a viabilidade dos processos de soldagem MIG-P CC+ e TIG-A aplicado ao passe de raiz em chapas de 200 x 200 x 12,75 mm da liga de alum?nio AA 5052. Para tal, foram analisadas configura??es diferentes de soldagem: o tipo de chanfro (em V e em gola com L=2,00 e 3,00 mm) e dois tipos de metais de adi??o (ER 4043 e 5356). Como metodologia de compara??o, foi determinada a mesma corrente de 150 A e taxa de deposi??o do metal de adi??o Va/Vs = 14, foram realizadas 8 combina??es de par?metros, cada uma com 3 repeti??es, totalizando 24 testes, salientando que foi usada apenas a configura??o de chanfro mais adequada para o TIG-A. S?o apresentados resultados da micrografia e microdureza das zonas fundida e termicamente afetada e n?veis de dilui??o para as juntas soldadas com os distintos metais de adi??o, al?m da radiografia. Nas condi??es estabelecidas neste trabalho, pode-se afirmar que o processo TIG-A apresentou melhores resultados em rela??o ao MIG-P CC+. Em rela??o ? configura??o do chanfro, o que se mostrou mais adequado foi o chanfro em V, para ambos os metais de adi??o e processos. N?o ocorreram defeitos como falta de fus?o, mordeduras e rugosidades. Em rela??o aos n?veis de dilui??o, foram constatados maiores valores quando utilizado o processo MIG-P CC+ para o ER 4043, assim como o processo TIG-A na configura??o de chanfro em V. O metal de adi??o ER 4043 apresentou uma quantidade de poros maior em rela??o ao ER 5356, em ambos os processos. Foi observada ? presen?a de um refino de gr?o, al?m de maiores n?veis de dureza em todas as soldas realizadas com o metal de adi??o ER 5356. / In many cases the root pass is a critical step of welding, since its execution is affected by several factors, such as variation of joint opening, chamfer angle, dimensions of the face (nose) root, torch inclination, welding speed and feed speed. Moreover, the choice of the welding process is a key factor to ensure the execution of a root pass with adequate mechanical and metallurgical properties. In this context, this work aimed to study the feasibility of MIG-P CC+ and TIG-A welding processes applied to the root pass in plates of 200 x 200 x 12,75 mm of the AA 5052 aluminum alloy. For this, different configurations of welding were analyzed: chamfer type(V and collar with L=1,0 and 3,00 mm) and two types of addition metals (ER 4043 and 5356). As compared methodology, It was determined the same current 150 A and the deposition rate of addition metal Va/Vs = 14, they were proposed 12combinations of parameters, each with 3repetitions, totaling 36 tests, stressing that It was used only the most appropriate chamfer setting for TIG-A. Results of micrograph and microhardness of fusion and heat affected zones and dilution levels for welded joints with diferente addition metals, beyond radiography. At the established conditions in this work, it can be said that the TIG-A process showed better results in relation to MIG-P CC+. About the chamfer configuration, which was more appropriate was V chamfer, for both addition metals and process. There were no defects such as lack of fusion, bites and roughness. Relative to dilution levels, higher values were observed when used the MIG-P CC+ process for the ER 4043, as well as TIG-A in the V chamfer configuration. ER 4043 addition metal showed a larger amount of pores in relation to the ER 5356, in both process. It was observed the presence of a grain refining, beyond higher hardness levels in all welds made with the ER 5356 addition metal.

Made available in DSpace on 2014-12-17T15:14:52Z (GMT). No. of bitstreams: 1 EduardoMD_DISSERT.pdf: 1460594 bytes, checksum: 3bdc57732c952c77e8ca0b42292d1e86 (MD5) Previous issue date: 2011-01-27 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this work we deposit via non-reactive magnetron sputtering of radio-frequency nanofilmes of nitreto of aluminum(AlN). The nanofilms aluminum nitride are semiconductors materials with high thermal conductivity, high melting point, piezoelectricity and wide band gap (6, 2 eV) with hexagonal wurtzite crystal structure, belonging to the group of new materials called III-V nitrides in which together with the gallium nitride and indium nitride have attracted much interest because they have physical and chemical properties relevant to new technological applications, mainly in microelectronic and optoelectronic devices. Three groups were deposited with thicknesses nanofilms time dependent on two substrates (glass and silicon) at a temperature of 25 ? C. The nanofilms AlN were characterized using three techniques, X-ray diffraction, Raman spectroscopy and atomic force microscopy (AFM), examined the morphology of these. Through the analysis of X-rays get the thickness of each sample with its corresponding deposition rate. The analysis of X-rays also revealed that nanofilms are not crystalline, showing the amorphous character of the samples. The results obtained by the technique, atomic force microscopy (AFM) agree with those obtained using the technique of X-rays. Characterization by Raman spectroscopy revealed the existence of active modes characteristic of AlN in the samples / Neste trabalho depositamos via magnetron sputtering de r?dio-frequ?ncia n?o reativo nanofilmes de nitreto de alum?nio (AlN). Os nanofilmes de nitreto de alum?nio s?o materiais semicondutores com alta condutividade t?rmica, elevado ponto de fus?o, piezoeletricidade e largo "bandgap"(6;2 eV) com estrutura cristalina wurtz?tica hexagonal, pertencentes ao grupo de novos materiais denominados nitretos III-V que em conjunto com o nitreto de g?lio e o nitreto de ?ndio t?m despertado muito interesse por possu?rem propriedades f?sico-qu?micas relevantes para novas aplica??es tecnol?gicas, principalmente em microeletr?nica e dispositivos optoeletr?nicos. Foram depositados tr?s grupos de nanofilmes com as espessuras depend?ntes do tempo, sobre dois tipos de substratos (vidro e sil?cio) a uma temperatura de 25?C. Os nanofilmes de AlN foram caracterizados usando tr?s t?cnicas, a difra??o de raios-X, espectroscopia Raman e microscopia de for?a at?mica (AFM), analisado-se a morfologia desses. Atrav?s da an?lise dos raios-X obtemos a espessura de cada amostra com sua respectiva taxa de deposi??o. A an?lise dos raios-X tamb?m revelou que os nanofilmes n?o s?o cristalinos, evidenciando o car?ter amorfo das amostras. Os resultados obtidos atrav?s da t?cnica, microscopia de for?a at?mica (AFM) concordam com os obtidos usando a t?cnica de raios-X. A caracteriza??o por espectroscopia Raman evidenciou a exist?ncia de modos ativos caracter?sticos do AlN nas amostras analisadas

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-27T12:30:35Z No. of bitstreams: 1 EraldoCamaraDeSouza_TESE.pdf: 1960987 bytes, checksum: aaf762025bc316dd0b3bce3590afc7a7 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-30T14:17:00Z (GMT) No. of bitstreams: 1 EraldoCamaraDeSouza_TESE.pdf: 1960987 bytes, checksum: aaf762025bc316dd0b3bce3590afc7a7 (MD5) / Made available in DSpace on 2017-01-30T14:17:00Z (GMT). No. of bitstreams: 1 EraldoCamaraDeSouza_TESE.pdf: 1960987 bytes, checksum: aaf762025bc316dd0b3bce3590afc7a7 (MD5) Previous issue date: 2016-07-22 / Neste trabalho foram obtidos comp?sitos alumina - tungst?nio (Al2O3 ? W), a partir da rea??o aluminot?rmica dos p?s de paratungstato de am?nia (APT) e alum?nio, misturados e mo?dos em moinho de alta energia. O p? obtido na moagem foi inserido numa tocha de plasma, impulsionado por um jato de arg?nio, e ao interagir com o plasma, foi aquecido abruptamente at? a temperatura de igni??o do alum?nio, reagindo exot?rmicamente. O produto da rea??o foi depositado sobre um substrato met?lico confeccionado em lat?o. Foram analisadas a influ?ncia da varia??o do fluxo de igni??o/alimenta??o e das dist?ncias tocha - substrato. Alternativamente, foi acoplado ? tocha, um dispositivo de confinamento do jato de plasma para as dimens?es do substrato. Os comp?sitos foram caracterizados quanto ? composi??o, fases e distribui??o de fases. A caracteriza??o das fases foi obtida por difra??o de raios X, a an?lise morfol?gica, atrav?s de microscopia eletr?nica de varredura - MEV e a an?lise qu?mica, atrav?s de espectroscopia de energia dispersiva - EDS. Os comp?sitos obtidos com o fluxo de plasma confinado apresentaram maior percentual de redu??o em rela??o a quantidade de W obtido, principalmente, com o fluxo de alimenta??o/igni??o de 5,0 l/min e 40mm de dist?ncia tocha-substrato. / In this work composite alumina ? tungsten (Al2O3 ? W) was obtained from the aluminothermic reaction of ammonium paratungstate (APT) and aluminum powders, mixed and grounded in high-energy mill. So the powder obtained was inserted in a plasma torch feeder, driven by a flux of argon, and when interacted with the plasma, was abruptly heated to the aluminum ignition temperature, reacts exothermically. The product of this reaction was deposited on a brass substrate. The influence of variation ignition/powder feeding as well as the distance from torch until substrate were analysed. Alternatively a confinement device for the plasma jet was attached in order to adjust the substrate dimensions. Chemical composition, phases and phase distribution of these composite materials were characterized. The X ? ray diffraction was used to analyze the existent phases; the Scanning Electron Microscopy (SEM) was used to perform the morphological aspect of the powder; and finally the Energy Dispersive Spectroscopy (EDS) was used for analyzing the chemical composition. The composites obtained by using confined plasma flux showed greater percentage reduction from the amount of W mainly when the feed/injection flow of 5 l/min and 40 mm of distance away torch-substrate were set up.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-08-01T11:55:04Z No. of bitstreams: 1 JoseRaelsonPereiraDeSouza_DISSERT.pdf: 2931697 bytes, checksum: 893ae580fb21bb765e576fb1a24663a9 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-08-02T14:19:30Z (GMT) No. of bitstreams: 1 JoseRaelsonPereiraDeSouza_DISSERT.pdf: 2931697 bytes, checksum: 893ae580fb21bb765e576fb1a24663a9 (MD5) / Made available in DSpace on 2017-08-02T14:19:30Z (GMT). No. of bitstreams: 1 JoseRaelsonPereiraDeSouza_DISSERT.pdf: 2931697 bytes, checksum: 893ae580fb21bb765e576fb1a24663a9 (MD5) Previous issue date: 2017-02-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Este trabalho apresenta o estudo da obten??o e caracteriza??o da reciclagem de alum?nio oriundo de latas de bebida composta pelas ligas de alum?nio AA3004, 5042 e 5182, atrav?s da t?cnica de moagem de alta energia e da metalurgia do p?. As latas foram selecionadas, picotadas e mo?das para obten??o do p? met?lico sob diferentes tempos de moagem (1h, 1h30min e 2h). O p? obtido foi compactado a uma carga de 400 MPa e sinterizado a 600 ?C por duas horas. Para caracteriza??o do p? de alum?nio foram realizadas an?lises em DRX, MEV e EDS, e granulometria a laser; enquanto o material consolidado por sinteriza??o, al?m das an?lises via DRX, MEV e EDS, foi caracterizado tamb?m atrav?s de ensaios de dilatometria, compress?o e microdureza Vickers. Avaliou-se o tamanho das part?culas e sua rela??o com as propriedades da liga de alum?nio. A rota de processamento adotada resultou na compacta??o efetiva do p? de alum?nio proveniente da moagem de latinhas de bebidas, por?m apresentando porosidade, t?pica de metais sinterizados. Observou-se uma grande incid?ncia de precipitados da fase Al6Mn dispersa na matriz Al-alfa (CFC). As amostras apresentaram varia??es em suas propriedades mec?nicas em fun??o do tempo de moagem. A porosidade e a microestrutura da liga podem ter influenciado as propriedades mec?nicas resultando no comportamento discrepante entre a resist?ncia a compress?o.e a microdureza. A resist?ncia a compress?o aumentou de 105 N/mm? com 1h de moagem para 120 N/mm? com 1h30min e diminui para 110 N/mm? com 2h de moagem, mas a ductilidade apresentou pouca varia??o. A dureza foi de 56,43 HV, 66,52 HV e 92,21 HV para os tempos de 1h, 1h30min e 2h, respectivamente. / This work presents the study of the production and characterization of aluminum recycling from beverage cans composed of aluminum alloys AA3004, 5042 and 5182, using high energy grinding and powder metallurgy. The cans were selected, punched and ground to obtain the metallic powder under different milling times (1h, 1h30min and 2h). The obtained powder was compacted at a load of 400 MPa and sintered at 600 ? C for two hours. For characterization of the aluminum powder, XRD, SEM and EDS analyzes were performed, and laser grading; While the material consolidated by sintering, in addition to the analyzes via DRX, SEM and EDS, was also characterized by Vickers dilatometry, compression and microhardness tests. The size of the particles and their relationship to the properties of the aluminum alloy were evaluated. The processing route adopted resulted in the effective compaction of the aluminum powder from the beverage cans mill, but with porosity, typical of sintered metals. A high incidence of precipitates of the Al6Mn phase dispersed in the Al-alpha matrix (CFC) was observed. The samples presented variations in their mechanical properties as a function of milling time. The porosity and microstructure of the alloy may have influenced the mechanical properties resulting in the dissimilar behavior between the compressive strength and microhardness. The compressive strength increased from 105 N / mm? with 1h grinding to 120 N / mm? with 1h30min and decreasing to 110N / mm? with 2h grinding, but the ductility presented little variation. The hardness was 56.43 HV, 66.52 HV and 92.21 HV for the times of 1h, 1h30min and 2h, respectively.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-11-01T21:11:49Z No. of bitstreams: 1 JulianoAugustoMedeirosDeMenezesEOliveira_DISSERT.pdf: 8358330 bytes, checksum: a0ec67f844a5bacdf6c24e821ebe74d1 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-11-07T19:34:30Z (GMT) No. of bitstreams: 1 JulianoAugustoMedeirosDeMenezesEOliveira_DISSERT.pdf: 8358330 bytes, checksum: a0ec67f844a5bacdf6c24e821ebe74d1 (MD5) / Made available in DSpace on 2017-11-07T19:34:31Z (GMT). No. of bitstreams: 1 JulianoAugustoMedeirosDeMenezesEOliveira_DISSERT.pdf: 8358330 bytes, checksum: a0ec67f844a5bacdf6c24e821ebe74d1 (MD5) Previous issue date: 2017-08-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / As ligas de alum?nio na composi??o eut?tica apresentam como caracter?stica baixa temperatura de fus?o e uma microestrutura complexa formada por constituintes eut?ticos. Elas podem ser aplicadas na ind?stria de fundi??o, por apresentarem adicionalmente alta fluidez e baixa tend?ncia ? forma??o de porosidade e de trincamento a quente. Foram produzidas por fundi??o em areia as ligas eut?ticas do sistema Al-Cu (bin?ria), Al-Cu-Si e Al-Cu-Mg (tern?rias) e Al- Cu-Si-Mg (quatern?ria). As ligas foram analisadas microestruturalmente no estado bruto de fus?o e no estado ap?s tratamento t?rmico de homogeneiza??o ? 495 ?C por at? 24 horas, via Fluoresc?ncia de Raios-X (FRX), Difra??o de Raios-X (DRX) e Microscopia Eletr?nica de Varredura (MEV) com sistema de Energia Dispersiva de Varredura (EDS). Os resultados mostraram a forma??o das principais fases constituintes no estado de equil?brio termodin?mico, a forma??o significativa de constituintes eut?ticos e a forma??o em pequena quantidade de intermet?licos Al5FeSi (plaquetas) e AlFeSiMgCu (escrita chinesa), comumente encontradas devido ? presen?a intr?nseca do ferro como impureza em ligas de alum?nio. / The aluminum alloys in the eutectic composition have a characteristic low melting temperature and a complex microstructure formed by eutectic constituents. They can be applied in the foundry industry, as they additionally present high fluidity and low tendency to the formation of porosity and hot cracking. The Al-Cu (binary), Al-Cu-Si and Al-Cu-Mg (ternary) and Al- Cu-Si-Mg (quaternary) systems were produced by sand casting. The alloys were analyzed microstructurally in the as-cast condition and after homogenizing heat treatment at 495 ? C for until 24 hours, via x-rays fluorescence (FRX), x-rays diffraction (XRD) and scanning electron microscopy (SEM) with dispersive scanning energy system (EDS). The results showed the formation of the main constituent phases in the thermodynamic equilibrium state, the significant formation of eutectic constituents and the formation of a small amount of intermetallic Al5FeSi (platelets) and AlFeSiMgCu (chinese writing), commonly found due to the intrinsic presence of iron as an impurity In aluminum alloys.

Made available in DSpace on 2014-12-17T14:09:16Z (GMT). No. of bitstreams: 1 JardelDC_TESE_Parcial.pdf: 1739659 bytes, checksum: 19974b9395e0d9fcb23b07c3997dab2f (MD5) Previous issue date: 2012-07-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The resistance of aluminum and their alloys, to the corrosion phenomenon, in aqueous solutions, is a result of the oxide layer formed. However, the corrosion process in the aluminum alloy is associated with the presence a second phase of particles or the presence of chloride ions which promote the disruption of the oxide layer located producing the corrosion process. On the other hand, the term water produced is used to describe the water after the separation of the oil and gas in API separators. The volumes of produced water arrive around 5 more times to the volume of oil produced. The greatest feature of the water is the presence of numerous pollutants. Due to the increased volume of waste around the world in the current decade, the outcome and the effect of the discharge of produced water on the environment has recently become an important issue of environmental concern where numerous treatments are aimed at reducing these contaminants before disposal. Then, this study aims to investigate the electrochemical corrosion behavior of aluminum alloy 6060 in presence of water produced and the influence of organic components as well as chloride ions, by using the electrochemical techniques of linear polarization. The modification of the passive layer and the likely breakpoints were observed by atomic force microscopy (AFM). In the pit formation potential around -0.4 to -0.8 V/EAg/AgCl was observed that the diffusion of chloride ions occurs via the layer formed with the probable formation of pits. Whereas, at temperatures above 65 ?C, it was observed that the range of potential for thepit formation was -0.4 to -0.5 V/EAg/AgCl. In all reactions, the concentration of Al(OH)3 in the form of a gel was observed / A resistencia do aluminio e suas ligas a corros?o em meio aquoso ? resultado da camada de oxido formada. Entretanto, o processo corrosivo nas ligas de alum?nio esta associado a presen?a de part?culas de segunda fase ou a presen?a de ions cloreto que promovem a ruptura da camada de ?xido produzindo o processo corrosivo localizado. Por outro lado, o termo ?gua produzida ? usado para descrever a ?gua ap?s a sua separa??o do ?leo e g?s nos separadores API. Os volumes de ?gua produzida chegam em m?dia de 5 vezes o volume do ?leo produzido. A maior caracter?stica dessa ?gua ? a presen?a de in?meros contaminantes. Devido ao aumento do volume dos res?duos em todo o mundo na d?cada atual, o desfecho e do efeito da descarga de ?gua produzida sobre o meio ambiente tem recentemente tornar-se uma quest?o importante de preocupa??o ambiental onde in?meros tratamentos s?o destinados a redu??o destes contaminantes antes do descarte. Ent?o, o presente estudo visa investigar o comportamento eletroquimico de corros?o da liga de aluminio 6060 em presen?a de ?gua produzida e a influencia dos componentes organicos assim como dos ions cloreto, atrav?s do uso das tecnicas eletroqu?micas de polariza??o linear. A modifica??o da camada passiva e os prov?veis pontos de ruptura foram observados por microscopia de for?a atomica (AFM). No potencial de forma??o de pit de -0,4 a -0,8 V/EAg/AgCl observa-se que ocorre a difus?o dos ?ons cloreto pela camada formada com prov?vel forma??o de pites. Entretanto, em temperaturas superiores a 65?C observou-se que a faixa de potencial de forma??o de pit foi de -0,4 a -0,5V/ EAg/AgCl. Em todas as rea??es observou-se o aumento na concentra??o de Al(OH)3 sob a forma de um gel / 2020-01-01

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-05-03T11:26:21Z No. of bitstreams: 1 2013 - Valeria Polese.pdf: 1777501 bytes, checksum: c11ce694e66877535a131581bb746469 (MD5) / Made available in DSpace on 2017-05-03T11:26:21Z (GMT). No. of bitstreams: 1 2013 - Valeria Polese.pdf: 1777501 bytes, checksum: c11ce694e66877535a131581bb746469 (MD5) Previous issue date: 2013-04-15 / AMPLA Energia e Servi?os S. A. / LIGHT Servi?os de Eletricidade S.A. / The present study looked for alternatives of growth handling and of pruning in plants used in the urban forestation, seeking to the decrease of conflicts of these with electric power spinnings. In the chapter I experiments were accomplished with Flamboyant in soil and simple nutritious solution containing Al, with objective of studying handling alternatives seeking to reduce the growth and development of plantules Flamboyant. The aluminum atrophies roots could affect the growth. Six experiments were accomplished with plantules (soil and simple nutritious solution) in conditions of growth camera and vegetation house, Department of Fitotecnia - UFRRJ. In the soil experiments they were used two sources of sulfate of aluminum, being a commercial one and a pure source analytically, in the concetrations 0, 100, 200, 300 and 400 kg ha-1 in the soils Planossolo and Argissolo, with four repetitions. The experiments accomplished in simple nutritious solution just received calcium (0,001 mM) and they had as source AlCl3 with doses that varied from 0,075 to 5,0 mM. Through the results of the chapter I was ended that in same or superior conditions of soil concentrations to 0,4 Cmolc/dm3 of Al caused toxicity to the plantules of Flamboyant, with effects mainly in the length root, and in solution simple nutritious doses same or upper to 0,075 mM of AlCl3 paralyzed the growth root. Al can be used as inhibitor of vegetable growth in plantules of Flamboyant. The chapter II had as objective studies the effects of the pruning and association with growth inhibitors in arboreal species. Four experiments were accomplished with the plants Sabi?, Sombreiro, and Cucumber (phytotoxicity Evaluation the herbicides). The experiments were installed in the Department of Fitotecnia-UFRRJ, Serop?dica. In the experiment 1 (Sabi?) all the plants were cut off 2 m of height, and they were applied the treatments: control, 2.4-D+Picloram, and Picloram. In the experiment 2 (Sabi?) all the plants were pruned removing 1/3 of the cup and applying the treatments: control, HCl, AlCl3, Picloram and nearby Cut (Without pruning of 1/3 of the cup). The experiment 3 (Sombreiro) had as treatments cut types in relation to the main trunk: nearby, leaving stub of 20 cm and of 40 cm. The experiment 4 (Pepino) it was installed in the originating from soil the first experiment with Sabi?. In the experiment 1, the treatment with Picloram delayed the beginning of the regrowth, important factor for the present study, so that they delay to arrive to the electric power spinning. In the experiment 2, just the treatment Picloram presented length and diameter of sprouts a little smaller in relation to the other treatments. In the experiment 3 it was verified that the nearby cut didn't present new budding until the 145 days after the pruning. In the experiment 4 the cucumber presented more intense toxicity in the treatment with Picloram. Was ended that Picloram and 2,4-D+Picloram were efficient for budding handling in adult plants of Sabi?, because they presented budding with small lengths, delaying the accomplishment of new pruning. In plants of Sombreiro the nearby cut was efficient, not presenting budding. It happened toxicity for Picloram in plants of Pepino. / O presente estudo buscou alternativas de manejo de crescimento e de poda em plantas utilizadas na arboriza??o urbana, visando ? diminui??o de conflitos destas com fia??es de energia el?trica. No cap?tulo I foram realizados experimentos com Flamboyant em solo e solu??o nutritiva simples contendo Al, com objetivo de estudar alternativas de manejo visando diminuir o crescimento e desenvolvimento de pl?ntulas Flamboyant. O alum?nio atrofia ra?zes podendo afetar o crescimento. Foram realizados seis experimentos com pl?ntulas (Solo e solu??o nutritiva simples) em condi??es de c?mara de crescimento e casa de vegeta??o, Departamento de Fitotecnia - UFRRJ. Nos experimentos de solo foram utilizadas duas fontes de sulfato de alum?nio, sendo uma comercial e uma fonte pura analiticamente, nas concentra??es 0, 100, 200, 300 e 400 kg ha-1 nos solos Planossolo e Argissolo, com quatro repeti??es. Os experimentos realizados em solu??o nutritiva simples receberam apenas c?lcio (0,001 mM) e tiveram como fonte AlCl3 com doses que variaram de 0,075 a 5,0 mM. Atrav?s dos resultados do cap?tulo I conclui-se que em condi??es de solo concentra??es iguais ou superiores a 0,4 Cmolc/dm3 de Al causaram toxicidade ?s pl?ntulas de Flamboyant, com efeitos principalmente no comprimento radicular, e em solu??o nutritiva simples doses iguais ou superiores a 0,075 mM de AlCl3 paralisaram o crescimento radicular. O Al pode ser utilizado como inibidor de crescimento vegetal em pl?ntulas de Flamboyant. O cap?tulo II teve como objetivo estudar os efeitos da poda e da sua associa??o com inibidores de crescimento em esp?cies arb?reas. Foram realizados quatro experimentos com as plantas Sabi?, Sombreiro, e Pepino (Avalia??o de fitotoxidade a herbicidas). Os experimentos foram instalados no Departamento de Fitotecnia-UFRRJ, Serop?dica-RJ. No experimento 1 (Sabi?) todas as plantas foram decepadas a 2 m de altura, e foram aplicados os tratamentos: Testemunha; 2,4-D+Picloram; e Picloram. No experimento 2 (Sabi?) todas as plantas foram podadas retirando 1/3 da copa e aplicando os tratamentos: Testemunha, HCl, AlCl3, Picloram e Corte rente (Sem poda de 1/3 da copa). O experimento 3 (Sombreiro) teve como tratamentos tipos de corte em rela??o ao tronco principal: rente, deixando toco de 20 cm e de 40 cm. O experimento 4 (Pepino) foi instalado no solo proveniente do primeiro experimento com Sabi?. No experimento 1, o tratamento com Picloram atrasou o in?cio da rebrota, fator importante para o presente estudo, a fim de que demorem chegar ? fia??o de energia el?trica. No experimento 2, apenas o tratamento Picloram apresentou comprimento e di?metro de brotos um pouco menores em rela??o aos demais tratamentos. No experimento 3 foi verificado que o corte rente n?o apresentou novas brota??es at? os 145 dias ap?s a poda. No experimento 4 o pepino apresentou toxidez mais intensa no tratamento com Picloram. Conclui-se que o Picloram e 2,4-D+Picloram foram eficientes para manejo de brota??es em plantas adultas de Sabi?, pois apresentaram brota??es com comprimentos pequenos, atrasando a realiza??o de nova poda. Em plantas de Sombreiro o corte rente foi eficiente, n?o apresentando brota??es. Ocorreu toxidez por Picloram em plantas de Pepino

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2018-08-30T16:36:02Z No. of bitstreams: 1 2009 - Aldir Carlos Silva.pdf: 1230710 bytes, checksum: 56dbab398ff37045b73bd259ab1a15ac (MD5) / Made available in DSpace on 2018-08-30T16:36:02Z (GMT). No. of bitstreams: 1 2009 - Aldir Carlos Silva.pdf: 1230710 bytes, checksum: 56dbab398ff37045b73bd259ab1a15ac (MD5) Previous issue date: 2009-03-06 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Aluminum tolerance studies in seedlings of Passion fruit (cvs. IAC-273/277, IACPaulista, IAC-275, FB-100) and Carica papaya (cvs.Taiung, Golden, Gran Golden, Baixinho de Santa Amalia) were performed in a growth chamber at the Laboratories of Chemistry of the Rhizosphere and Seeds of the Department of Fitotecnia, of University Federal Rural of Rio Janeiro, Institute of Agronomy. Experiments with different concentrations of Al were conducted in nutrient solution simple (with Ca) and complete, with the aims to analyze the tap root length, ratio of root lengths, relative root elongation, diameter of root and stem and effect of stains. Also were conducted experiments with seeds soaked in different concentration of Al to verify the percentage of germination, seedlings normal and abnormal. The use of simple nutrient solution was not satisfactory to shown the performance of seedlings of papaya. In passion fruit both nutrient solutions can be used in short term experiment. Over the concentration of 160?M of Al occurred effect of toxicity in root of seedlings of passion fruit and papaya, but at concentrations lower that 80?M there were stimulus of growth. The tap root length was the more efficient parameter to compare root toxicity. The soaking of seeds in the solution of aluminum did not affect the germination, root tap emission and the growth of seedlings until 1280?M. With the increased of time of contact with the Al solution, the young roots have been injured especially in papaya seedlings. The use of stains pyrocatechol violet and hematoxylin were both efficient to determinate the aluminum tolerance in papaya and passion fruit, but just pyrocatechol violet could compare the doses used, produced a color gradient with increasing concentration of aluminum. With the use of hematoxylin was only possible to separate the high concentrations of low concentrations of aluminum. The best passion fruit cultivar was IAC 273/277and papaya was Tainung / Os estudos da toler?ncia ao alum?nio em pl?ntulas de maracuj? (cvs. IAC-273/277, IACPaulista, IAC-275, FB-100) e mam?o (cvs.Tainug, Golden, Gran Golden, Baixinho de Santa Am?lia) foram realizados, em c?mara de crescimento nos Laborat?rios de Qu?mica da Rizosfera e Laborat?rio de Analise de Sementes, Departamento de Fitotecnia, Instituto de Agronomia da Universidade Federal Rural Rio de Janeiro. Foram realizados experimentos com diferentes concentra??es de alum?nio em solu??o nutritiva simples (com c?lcio) e completa, para analise do crescimento radicular utilizando os par?metros comprimento radicular, taxa de crescimento radicular, elonga??o radicular relativa, di?metro do colo, di?metro de ?pice da raiz principal bem como testes com corantes. Foi tamb?m realizado estudos do efeito da embebi??o das sementes com solu??es de alum?nio para verificar o efeito na porcentagem de germina??o, pl?ntulas normais e anormais, e n?o germinadas. O uso da solu??o nutritiva simples para realizar testes de curta dura??o de contacto ao alum?nio, n?o foi satisfat?rio para mam?o, sendo mais adequado o uso de solu??o nutritiva completa. Em maracuj?, ambas as solu??es podem ser utilizadas. As pl?ntulas de maracuj? crescidas em solu??o simples com o aumento do tempo de contacto com alum?nio na solu??o, as ra?zes ficaram endurecidas. Em concentra??es acima de 160?M de alum?nio, ocorreu efeito fitotoxico, contudo em concentra??es menores que 80?M ocorreu at? aumento do crescimento radicular para mam?o e maracuj?. O comprimento radicular foi o mais eficiente par?metro indicador da toler?ncia ao alum?nio. A embebi??o das sementes em alum?nio n?o afetou a germina??o a emiss?o da raiz principal e o crescimento da pl?ntula at? a concentra??o da solu??o de embebi??o de 1280?M, mas a medida que aumentou o tempo de contato e a concentra??o de alum?nio, as ra?zes rec?m emitidas sofreram danos, principalmente as de pl?ntulas de mam?o. O uso dos corantes qu?micos violeta de pirocatecol e hematoxilina foram eficiente na determina??o da toler?ncia ao alum?nio em maracuj? e mam?o, mais somente o violeta de pirocatecol permitiu comparar as doses entre si, gerando um gradiente de colora??o com o aumento da concentra??o de alum?nio, com o uso da hematoxilina s? foi poss?vel separar as concentra??es altas das concentra??es baixas de alum?nio. As melhores cultivares nas condi??es testadas foi a IAC 273/277 de maracuj? e a cv Tainung de mam?o