Made available in DSpace on 2015-04-14T13:58:25Z (GMT). No. of bitstreams: 1 398972.pdf: 1270520 bytes, checksum: c981dc4ef6d67b9a25e1efbb0fef41df (MD5) Previous issue date: 2008-01-15 / Este trabalho apresenta um estudo comparativo entre sistemas catal?ticos para a rea??o de transesterifica??o dos ?leos de farelo de arroz. A transesterifica??o do ?leo do farelo de arroz refinado com metanol foi avaliada na presen?a de acido sulf?rico (H2SO4) e compostos de estanho como: cloreto de estanho (SnCl2. 2H2O), 2-etilhexanoato de estanho (Sn(C8H15O2)2), conhecido comercialmente como DBTDL. Os produtos das rea??es foram caracterizados atrav?s da analise comparativa entre os catalisadores, verificou-se uma melhor performance para o DBTDL, com rendimento de 99,9% , no tempo de 4h e rela??es molares de 480:100:5 entre ?lcool, ?leo e catalisador, respectivamente . Estes resultados demonstram a viabilidade do uso de compostos met?licos como catalisadores na obten??o de biodiesel, uma alternativa interessante a catalise acida e b?sica. Nas otimiza??es do processo, foram avaliadas alcoolizes com metanol e etanol, as razoes molares foram variadas e foram utilizados como ?leo de partida, alem dos ?leos refinados, tamb?m ?leos degomados e brutos.

Made available in DSpace on 2015-04-14T13:58:45Z (GMT). No. of bitstreams: 1 436188.pdf: 5507987 bytes, checksum: bb7dbc2c844572b613d5bebdeb70d2ae (MD5) Previous issue date: 2011-08-18 / Since the biodiesel national programs began, many research groups have been studied this fuel efficiency, such as economical aspects, environments effects and engine performance and durability. The research objective was project and build a pin-on-disk device test per ASTM G99 95a (Standard Test Method for Wear Testing with a Pin-on-Disk Apparatus) to test material wear under diesel (B5) biodiesel (B100). The project validation was realized by performing aluminum-silicon wear test under two conditions: in presence of diesel (B5) and in presence of biodiesel (B100), with fix speed of 220 rpm, pin load of 5 N and 8 N during 150,000 cycles. The test analysis desired to compare the wear of an alloy used in diesel engines under different solutions. After the wear test, the disc weight loss, the topography and the microstructure were analyzed. The qualitative preliminary result shows better lubricates of biodiesel (B100) to test conditions adopted. / Desde o surgimento dos programas nacionais para a adi??o de biodiesel no diesel, diversos grupos t?m estudado a efic?cia deste combust?vel, abordando aspectos econ?micos, de meio ambiente, desempenho e durabilidade dos motores diesel. O presente trabalho tem o objetivo de projetar, construir e testar um trib?metro para an?lise de materiais submersos em biodiesel e diesel. O equipamento de teste foi desenvolvido tendo como refer?ncia a norma ASTM G99 95a (Standard Test Method for Wear Testing with a Pin-on-Disk Apparatus). A valida??o do projeto se realizou mediante ensaios de desgaste da liga alum?niosil?cio AA305 em duas condi??es: na presen?a de diesel (B5) e na presen?a de biodiesel (B100), com rota??o fixa de 220 rpm, e for?as de 5 N e 8 N durante per?odos de 150.000 ciclos. As an?lises dos dados tiveram como finalidade fazer um comparativo do desgaste da liga em estudo, utilizada em motores diesel, em diferentes solu??es. Ap?s os ensaios foram analisadas as perdas de massa, a topografia do disco e a microestrutura. A an?lise qualitativa das amostras indicou melhor lubricidade do biodiesel (B100) para as condi??es de teste adotadas.

Submitted by Kelson Anthony de Menezes (kelson@ucb.br) on 2016-11-23T12:14:00Z No. of bitstreams: 1 JessicaCarvalhoBergmannTeseparcial2013.pdf: 124515 bytes, checksum: 0d2877a5336a887b74ef27ed08081d9a (MD5) / Made available in DSpace on 2016-11-23T12:14:00Z (GMT). No. of bitstreams: 1 JessicaCarvalhoBergmannTeseparcial2013.pdf: 124515 bytes, checksum: 0d2877a5336a887b74ef27ed08081d9a (MD5) Previous issue date: 2013-10-07 / The necessity to be a self-suficient producer of fuels is stimulating research for alternative types of energy. Brazil, as well as other countries, is investing in this sector and in 2012 was the second largest biofuel producer in the world. Bioethanol production can double productivity with second generation technology in which bioethanol is produced from cellulose. Biodiesel production from oils using different feedstocks can also contribute for this independency in biofuels production, both locally and globally. This doctorate thesis is divided in two chapters, both attempting to make a contribution to the development of the biofuels sector in Brazil. The first chapter focuses on enzyme discovery for ethanol production from cellulose. The second chapter focuses on the characterization of the soil microbiota associated with oil palm plants with fatal yellowing, which has hindered the development of a biodiesel industry based on palm oil. The first chapter describes prospection for hydrolytic enzymes to be used for biomass deconstruction in second generation bioethanol production. Enzymes were screened from an Amazon soil large insert metagenomic library (30-50 kb). The library containing approximately 213,000 clones was functionally screened, and 15 clones with cellulolytic activity and 16 clones resistant to hydroquinone were identified. The sequences of these 31 clones and an additional 65 other random clones were obtained and analysed using the IMG/MER pipeline. In silico analysis identified several coding regions (CDS) that were amplified by PCR and cloned in expression vectors. The sequences for two beta-glucosidases enzymes, BGL17 and BGL18, were codon optimized before being expressed and purified. Characterization of both enzymes showed that the optimum temperature for BGL17 and BGL18 was 45oC and 40oC, respectively. The optimum pH for BGL17 and BGL18 was 6.0 and for 6.5, respectively. Half-life stability was approximately one hour for both enzymes. Regarding enzyme kinetics, BGL18 showed higher Vmax and Km (11 U/mg ?? 0.0011 and 0.36 mM ?? 0.01612) when compared to BGL17 (85 U/mg ?? 0.0028 and 0.30 mM ?? 0.017). Kcat was only calculated for BGL17 as 38.57 s-1 ?? 0.37 as the purification of BGL18 was not successfull. Chapter two aimed to study the soil bacterial diversity from oil palm trees affected by fatal yellowing disease (bud rot) in three different stages. The strategy used was pyrosequencing of the gene for the 16S ribosomal RNA (16S rRNA). Oil palm is an oilcrop produced in the north region of Brazil with hight oil yield, which makes it a good candidate for biodiesel production. However, oil palm trees are being affected by fatal yellowing (FY) for more than 20 years, but to this date no etiological agent was identified. Observation was reported where healthy palm tree were planted in the same spot as previously sick tree, developed FY after a period of time, suggesting that the disease could be transmitted by some microorganism in the soil. In this work, the gene for 16S rRNA was amplified from DNA extracted from soil of diseased oil palm trees (stages 5 and 8) and from plants with no symptoms of the disease and sequenced. Pyrosequencing originated 839,694 sequences. After artifacts and chimeras were removed, 498,397 sequences distributed in 9 samples (3 for each disease stage) remained to be analyzed. Sequences were analyzed using the Qiime pipeline (Quantitative Insights in Microbial Ecology) and taxonomic classification of sequences was obtained based on the RDP (Ribossomal Database Project). The most abundant phyla in the samples were Acidobacteria, Proteobacteria, Planctomycetes, Firmicutes and Verrucomicrobia. Alpha and Beta diversity were calculated and taxonomic comparisons were performed by STAMP software. Results showed that the bacterial communtiy associated with soils of diseaded plants on stage 5 (DCA5) and stage 8 had a higher number of observed OTUs than stage 0, as determined by the Chao1 phylogenetic diversity index. Beta-diversity analysis showed that the different biological replicates of soil from diseased plants of the same stage are significantly different, as shown in PCoA (Principal Coordenate Analysis). Taxonomic comparison showed more rare phyla associated to stages 5 and 8 of the disease. This work is the first to study the bacterial microbiota associated with soils of oil palm plants with and without symptoms of fatal yellowing with next generation sequencing. / A necessidade de produzir combust??veis para que futuramente haja independ??ncia na produ????o de energia, vem impulsionando pesquisas no setor de energias alternativas. O Brasil, assim como outros pa??ses emergentes, tem investido e ganhado espa??o neste cen??rio, sendo hoje o segundo maior produtor mundial de biocombust??veis. A produ????o de bioetanol, apesar de j?? bem estabelecida no pa??s, poder?? dobrar com a tecnologia de produ????o de etanol de segunda gera????o (a partir da biomassa). Al??m disso, com a produ????o de biodiesel a partir do ??leo de diferentes culturas oleaginosas poder?? contribuir para esta independ??ncia na produ????o de biocombust??veis localmente e globalmente. Esta tese est?? dividida em dois cap??tulos, ambos tratando como produto final a produ????o de biocombust??veis. O cap??tulo um teve como objetivo a prospec????o de enzimas hidrol??ticas para serem utilizadas durante o processo de hidr??lise enzim??tica e clones resistentes a produtos secund??rios formados durante o processo de pr??-tratamento na produ????o de etanol de segunda gera????o. Construiu-se uma biblioteca metagen??mica de grandes insertos (30-50 kb) em fosm??deo a partir de DNA da comunidade microbiana do solo amaz??nico. A biblioteca contendo aproximadamente 213.000 clones foi triada funcionalmente, identificando 15 clones com atividade celulol??tica e 16 clones resistentes ?? hidroquinona (produto t??xico a leveduras produzido durante o pr??tratamento). Estes 31 clones com atividade na triagem funcional, somados a outros 65 clones selecionados aleatoriamente, foram sequ??nciados e suas sequ??ncias depositadas no pipeline IMG/MER (JGI) onde foram anotadas. A an??lise computacional dos clones com atividades enzim??ticas permitiu a identifica????o de diferentes regi??es codificantes (CDs) que foram amplificadas por PCR e clonadas em vetores de express??o. Conseguiu-se a express??o de duas enzimas beta-glicosidases (BGL17 e BGL18) que tiveram suas sequ??ncias otimizadas antes de serem purificadas. A caracteriza????o destas enzimas mostrou que a BGL17 e BGL18 possuem uma temperatura ??tima de 45oC e 40oC, respectivamente, e um pH ??timo de 6 e 6,5, respectivamente, com estabilidade m??dia nestas condi????es em torno de uma hora. A BGL17 possui um valor de Vmax e Km de 85 U/mg e 0,30 mM ?? 0.017 enquanto a BGL18 possui os valores de Vmax e Km de 11,01 U/mg e 0,36 mM ?? 0,01612. O cap??tulo dois visou o estudo da microbiota de solo de dendezeiros acometidos pelo amarelecimento fatal (AF) em diferentes est??gios da doen??a utilizando como estrat??gia o pirosequenciamento do gene para 16S rRNA. A planta do dend?? ?? uma oleaginosa produzida principalmente no norte do Brasil e possui um alto rendimento de ??leo o que a torna uma boa candidata a produ????o de biodiesel. Por??m, o dendezeiros t??m sido acometidos pelo AF, sendo seu agente etiol??gico procurado h?? mais de 20 anos sem resultados conclusivos. Plantas sadias que foram replantadas no mesmo lugar de plantas doentes desenvolveram a doen??a, criando-se a hip??tese da transmiss??o do AF ocorrer pelo solo. Neste trabalho, realizou-se o pirosequenciamento do gene para 16S rRNA amplificado da comunidade bacteriana de uma amostra de solo da base de dendezeiros acometidos por AF em dois est??gios da doen??a (est??gio 5 e est??gio 8) e aparentemente sem doen??a (est??gio 0). O sequenciamento gerou 839.694 sequ??ncias que depois de retirados os artefatos totalizaram 498.397 sequ??ncias distribu??das em 9 pontos (3 para cada est??gio da doen??a). As sequ??ncias foram analisadas utilizando-se o programa Qiime (Quantitative Insights in Microbial Ecology) e sua classifica????o taxon??mica atribu??da de acordo com o RDP-II (Ribossomal Database Project). Os filos mais abundantes encontrados foram Acidobacteria, Proteobacteria, Planctomycetes, Firmicutes e Verrucomicrobia. An??lises de alfa e beta diversidade foram realizadas e compara????es taxon??micas foram feitas utilizando o programa STAMP (Statistical Analysis of Metagenomic Profiles). Os resultados mostraram que os pontos DCA5 (dendezeiros com AF no est??gio 5 da doen??a) apresentam maior quantidade de OTUs observadas em rela????o a diversidade filogen??tica e ??ndice de Chao1. As an??lises de beta-diversidade mostraram que os agrupamentos entre os pontos por sintomas da doen??a s??o significativamente diferentes. Compara????es taxon??micas mostraram uma maior presen??a de filos raros nos est??gios 5 e 8. Este trabalho foi o primeiro realizado tentando elucidar o causador do AF utilizando sequenciamento de ??ltima gera????o. Estes resultados ir??o contribuir para futuros estudos do Amarelecimento Fatal.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-11-22T20:18:42Z No. of bitstreams: 1 CleonilsonMafraBarbosa_TESE.pdf: 4055728 bytes, checksum: 4de55338df2c07716d2c555f19dcc09a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-11-22T23:43:24Z (GMT) No. of bitstreams: 1 CleonilsonMafraBarbosa_TESE.pdf: 4055728 bytes, checksum: 4de55338df2c07716d2c555f19dcc09a (MD5) / Made available in DSpace on 2017-11-22T23:43:24Z (GMT). No. of bitstreams: 1 CleonilsonMafraBarbosa_TESE.pdf: 4055728 bytes, checksum: 4de55338df2c07716d2c555f19dcc09a (MD5) Previous issue date: 2017-07-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Esse trabalho prop?s uma rota alternativa de s?ntese de catalisadores para rea??es de oxida??o do metanol e etanol a serem aplicados em c?lulas a combust?vel, sendo estes a base de ?xidos e precursores mistos de ni?bio e t?ntalo puros e dopados com cobalto, cobre e n?quel, obtidos a partir do mineral de base, a columbita/tantalita. Inicialmente, foi efetivado um planejamento experimental da purifica??o total deste min?rio, na sequ?ncia, foi realizada a dopagem usando um percentual de 10%, em massa. Os tratamentos t?rmicos foram realizados em tr?s diferentes temperaturas (110, 400 e 600 ?C). Na sequ?ncia, foi efetivada a s?ntese do precursor oxalato, que foi utilizado, por conseguinte, na s?ntese dos precursores dopados onde estes passaram pelos mesmos procedimentos dos ?xidos. O min?rio puro e tratado foi caracterizado por fluoresc?ncia de raios X (FRX) e difra??o de raios X (DRX) que mostraram a sua total purifica??o. O precursor foi avaliado atrav?s das an?lises de difra??o de raios X (DRX), espectroscopia de infravermelho (IV), an?lises t?rmicas (TG/DTG/DSC e DTA) e a microscopia eletr?nica de varredura (MEV); apresentando part?culas inferiores a 0,2 micrometros, um alto valor de perda de massa (76,6 %) e uma estrutura porosa de formas irregulares. Os catalisadores puros e dopados foram submetidos ?s an?lises por difra??o de raios X (DRX), espectroscopia de fotoel?trons excitados por raios X (XPS), microscopia eletr?nica de varredura (MEV) e microscopia eletr?nica de transmiss?o (MET), que apresentaram fortes ind?cios de propriedades catal?ticas para a oxida??o devido a sua r?pida redu??o. Na caracteriza??o el?trica, estes catalisadores foram avaliados pela t?cnica da voltametria de pulso diferencial (DPV) atrav?s de sensores em rea??o para a oxida??o dos ?lcoois. As an?lises demonstraram que estes materiais s?o ?timos condutores, porque aumentaram a passagem de corrente el?trica do eletrodo de trabalho em at? duas ordens de grandeza superior ao eletrodo de ouro. Os melhores desempenhos para as rea??es foram observados principalmente com o dopante de cobre, seguido por o n?quel, o puro e depois o de cobalto, considerando ainda que os materiais obtidos possuem caracter?sticas apropriadas para aplica??o em eletrodos de c?lulas a combust?vel. / This paper proposes an alternative route for producing catalysts for methanol and ethanol oxidation reactions to be applied on fuel cells. Those catalysts are based on oxides and precursors of mixed niobium and tantalum materials in their pure and doped (with Co, Cu or Ni) forms. These materials are obtained from columbite/tantalite, which is the base mineral for Nb, Ta. At first, an experimental planning for the complete purification of the mineral was performed. After purification, 10%wt. doping with each of the metals, and thermal treatment at three different temperatures (110,400 and 600?C) was carried out. Un-doped purified oxides were then subject to complexation process followed by metal addition (doping) and thermal treatment. Purified and thermally treated mineral was characterized by X-Ray Fluorescence (XRF) and X-Ray Diffraction and complete purification was attained. Complex precursors were evaluated on the basis of XRD, Infra-Red Spectroscopy (IR), thermal behavior (TG/DSC and DTA) and morphology (Scanning Electron Microscopy) and presented particle sizes under 0.2 ?m, elevated weight loss (76.6%) and a porous structure of irregular shape. Pure and doped catalysts were characterized on XRD, XPS (X-Ray Excited Photon Spectroscopy), SEM and TEM (Transmission Electron Microscopy) basis, presenting indication of catalytic properties interesting for oxidation reactions, such as quick surface reduction. Electrical evaluation of the catalysts was performed according to Differentia Pulse Voltammetry (DPV) with the use of micro sensors during alcohol oxidation reactions. These analyses indicated the excellent conducting characteristics of the materials as electric current flow was increased in two orders of magnitudes in comparison to gold electrodes. The best catalytic behaviors were observed when dopping was performed with copper, followed by nickel, without and cobalt dopant addition. Therefore, the synthesized materials presented characteristics that indicate their suitability for use as fuel cells electrodes.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-04T20:21:19Z No. of bitstreams: 1 RayanaHozanaBezerril_TESE.pdf: 1462425 bytes, checksum: cac67c7bf1570bf9fe04615be96e17d0 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-09T23:46:58Z (GMT) No. of bitstreams: 1 RayanaHozanaBezerril_TESE.pdf: 1462425 bytes, checksum: cac67c7bf1570bf9fe04615be96e17d0 (MD5) / Made available in DSpace on 2015-12-09T23:46:58Z (GMT). No. of bitstreams: 1 RayanaHozanaBezerril_TESE.pdf: 1462425 bytes, checksum: cac67c7bf1570bf9fe04615be96e17d0 (MD5) Previous issue date: 2014-07-25 / Dentre as atividades econ?micas potencialmente poluidoras que comprometem a qualidade do solo e da ?gua subterr?nea est?o os postos revendedores de combust?veis. O vazamento de combust?veis derivados do petr?leo a partir de tanques subterr?neos ou atividades realizadas indevidamente com estes poluentes podem contaminar extensas ?reas, causando s?rios problemas ambientais e toxicol?gicos. O n?mero de postos de combust?veis cresceu desordenadamente, sem nenhum tipo de controle, com isso os impactos ambientais gerados por esses empreendimentos cresceram ocasionando a polui??o do solo e da ?gua subterr?nea. V?rias t?cnicas utilizando tensoativos t?m sido propostas para remedia??o deste tipo de contamina??o. Este estudo apresenta como inova??o a aplica??o de diferentes sistemas contendo tensoativos na fase vapor e compara suas efici?ncias de remo??o de diesel de um solo contendo esse contaminante. Para isso, foi utilizado um sistema que cont?m sete po?os injetores das seguintes solu??es vaporizadas : ?gua, solu??es de tensoativo, microemuls?o e nanoemuls?o, Os tensoativos utilizados foram o ?leo de Coco Saponificado (OCS), em solu??o aquosa e um ?lcool etoxilado UNTL-90: em solu??o aquosa, e em sistemas de microemuls?o e nanoemuls?o. Dentre os sistemas investigados, a nanoemuls?o foi a que apresentou maior efici?ncia de remo??o com 88% do diesel, sendo a mais vi?vel ecol?gica e tecnicamente por ser um sistema com menor teor de mat?ria ativa. / Among the potentially polluting economic activities that compromise the quality of soil and groundwater stations are fuel dealers. Leakage of oil derived fuels in underground tanks or activities improperly with these pollutants can contaminate large areas, causing serious environmental and toxicological problems. The number of gas stations grew haphazardly, without any kind of control, thus the environmental impacts generated by these enterprises grew causing pollution of soil and groundwater. Surfactants using various techniques have been proposed to remedy this kind of contamination. This study presents innovation as the application of different systems containing surfactant in the vapor phase and compares their diesel removal efficiencies of soil containing this contaminant. For this, a system that contains seven injection wells the following vaporized solutions: water, surfactant solution, microemulsion and nanoemulsion, The surfactants used were saponified coconut oil (OCS), in aqueous solution and an ethoxylated alcohol UNTL-90: aqueous solution , and nanoemulsion and microemulsion systems. Among the systems investigated, the nanoemulsion showed the highest efficiency, achieving 88% removal of residual phase diesel, the most ecologically and technically feasible by a system with lower content of active matter

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-08T22:38:21Z No. of bitstreams: 1 RobsonGuimaraesSanabio_TESE.pdf: 5116561 bytes, checksum: 312e2468286ab5c95fe5eb204d4a9168 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-11T21:47:26Z (GMT) No. of bitstreams: 1 RobsonGuimaraesSanabio_TESE.pdf: 5116561 bytes, checksum: 312e2468286ab5c95fe5eb204d4a9168 (MD5) / Made available in DSpace on 2016-04-11T21:47:26Z (GMT). No. of bitstreams: 1 RobsonGuimaraesSanabio_TESE.pdf: 5116561 bytes, checksum: 312e2468286ab5c95fe5eb204d4a9168 (MD5) Previous issue date: 2015-05-22 / A adi??o de hidrog?nio gasoso como fonte alternativa de combust?vel vem sendo largamente utilizada. Hoje em dia, v?rias experi?ncias est?o em andamento para a utiliza??o de geradores de hidrog?nio (eletrolisadores) por demanda em ve?culos automotores. Em todos os an?ncios desses produtos seus fabricantes afirmam que este procedimento fornece uma redu??o de consumo de combust?vel, reduz os n?veis de emiss?o de gases t?xicos pela descarga e melhora a vida ?til do motor. A presente pesquisa faz uma an?lise da estrutura f?sica de pe?as de motores que utilizam eletrolisadores por demanda. Para isto, foi montado um sistema estacion?rio com um motogerador de energia el?trica, monocil?ndrico, e adaptados dois eletrolisadores um de c?lula seca e outro de c?lula molhada. Nas etapas de observa??o, foram feitas an?lises de consumo em quatro faixas de carga de trabalhos e observado o pist?o do motor, que foi cortado e analisado por microscopia ?tica (MO), Microscopia Eletr?nica de Varredura e de Energia Dispersiva (MEV-EDS), Microscopia Confocal e Difra??o de Raios - X (DRX), no sistema estacion?rio, em cada etapa. Os resultados mostraram uma redu??o consider?vel no consumo de combust?vel e uma corros?o acentuada no pist?o original de f?brica, feito de liga alum?nio-sil?cio. Como barreira ? corros?o foi feita uma nitreta??o por plasma na cabe?a do pist?o, que se mostrou resistente ao ataque pelo hidrog?nio, embora tenha apresentado evid?ncias de tamb?m ter sido atacada. Concluiu-se que os eletrolisadores automotivos podem ser uma boa op??o em termos de consumo e redu??o de emiss?es de gases t?xicos, por?m o material das c?maras de combust?o dos ve?culos devem ser preparados para este fim. / The addition of hydrogen gas as an alternative fuel source has been widely used, as well reported in scientific literature. Today, several experiments are underway for the use of hydrogen generators (electrolysers) demand for motor vehicles. In all these products their ads manufacturers claim that this provides a reduction of fuel consumption, reduces the emission levels of toxic gas by the discharge and improves engine life. This research analyzes the physical structure of engine components using electrolysis on demand. To this end, a stationary system was fitted with a power generator of electricity, drum roller and adapted two electrolyzers: a dry cell and wet cell other. In steps observation were consumption analyzes in four work load ranges and observing the piston engine, which has been cut and analyzed by Optical Microscopy (OM), Scanning Electron Microscopy and Dispersive Energy (SEM-EDS), X ? Ray Diffraction (XRD) and Confocal Microscopy, the stationary system in each step. The results showed a considerable reduction in fuel consumption and a high corrosion in the original factory piston constituted of aluminum-silicon alloy. As corrosion barrier was made a plasma nitriding in the piston head, which proved resistant to attack by hydrogen, although it has presented evidence also, of having been attacked. It is concluded that the automotive electrolysers can be a good choice in terms of consumption and reducing toxic gas emissions, but the material of the combustion chambers of vehicles must be prepared for this purpose.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-06-09T23:48:16Z No. of bitstreams: 1 PauloAntonioMacedoSilva_TESE.pdf: 3938129 bytes, checksum: 33a58d5ed902b34a959919327356aca8 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-06-10T20:54:26Z (GMT) No. of bitstreams: 1 PauloAntonioMacedoSilva_TESE.pdf: 3938129 bytes, checksum: 33a58d5ed902b34a959919327356aca8 (MD5) / Made available in DSpace on 2016-06-10T20:54:26Z (GMT). No. of bitstreams: 1 PauloAntonioMacedoSilva_TESE.pdf: 3938129 bytes, checksum: 33a58d5ed902b34a959919327356aca8 (MD5) Previous issue date: 2015-10-26 / No presente trabalho mostra que a s?ntese por combust?o, destaca-se como uma t?cnica alternativa para obten??o dos p?s-cer?micos de ?xidos superiores, nanoestrutrurados e de alta pureza, como as ferritas de f?rmulas Co(1-x)Zn(x)Fe2O4 e Ni(1-x)Zn(x)Fe2O4 com x variando de 0,2 mols, num intervalo de 0,2 ? x ? 1,0 mol, que apresentam propriedades, magn?ticas, em que ocorre ? coexist?ncia de estado ferroel?trico e ferrimagn?tico, as quais podem ser utilizadas em antenas de micro fitas e superf?cies seletivas de frequ?ncias em faixas de micro-ondas miniaturizadas, sem perda de desempenho. A obten??o ocorreu atrav?s do processo de combust?o e de processos f?sicos adequados a utiliza??o ao m?todo de sinteriza??o do substrato, resultando um material cer?mico, de elevado grau de pureza nanom?trico. An?lises no Magnet?metro de Amostra Vibrante (MAV) mostraram que estes materiais ferriticos apresentam par?metros como histereses de materiais que possuem comportamento pr?prio dos materiais magn?ticos de boa qualidade, em que os estados de magnetiza??o podem ser mudados bruscamente com uma varia??o relativamente pequena da intensidade do campo, tendo assim grandes aplica??es no campo de eletroeletr?nicos. A caracterizaram dos p?s-cer?micos sinterizados a 900?C, como suas propriedades estruturais, geom?tricas, tamanho do cristalito e dist?ncia Interplanar, foram feitas por Difra??o de Raios-X (DRX). Foram feitas outras an?lises, como a Microscopia Eletr?nica de Varredura (MEV), Fluoresc?ncia de Raios-X (FRX) , a permissividade el?trica e a tangente de perda, em altas frequ?ncias, atrav?s do aparelho ZVB - 14 Vector Network Analyzer 10 MHz-14 GHz, da ROHDE & SCHWART. / This work shows that the synthesis by combustion is a prominent alternative to obtain ceramic powders of higher oxides, nanostructured and of high purity, as the ferrites of formulas Co(1-x)Zn(x)Fe2O4 e Ni(1-x)Zn(x)Fe2O4 with x ranging from 0.2 mols, in a range from 0.2 ? x ? 1.0 mol, that presents magnetic properties in coexistence of ferroelectric and ferrimagnetic states, which can be used in antennas of micro tapes and selective surfaces of low frequency in a range of miniaturized microwaves, without performance loss. The obtainment occurred through the combustion process, followed by appropriate physical processes and ordered to the utilization of the substrate sinterization process, it gave us a ceramic material, of high purity degree in a nanometric scale. The Vibrating Sample Magnetometer (VSM) analysis showed that those ferritic materials presents parameters, as materials hysteresis, that have own behavior of magnetic materials of good quality, in which the magnetization states can be suddenly changed with a relatively small variation of the field intensity, having large applications on the electronics field. The X-ray Diffraction (XRD) analysis of the ceramic powders synthesized at 900 ?C, characterize its structural and geometrical properties, the crystallite size and the interplanar spacing. Other analysis were developed, as Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF), electric permittivity and the tangent loss, in high frequencies, through the equipment ZVB - 14 Vector Network Analyzer 10 MHz-14 GHz, of ROHDE & SCHWART.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-08T21:06:56Z No. of bitstreams: 1 FabioPimentaDeLira_DISSERT.pdf: 2588802 bytes, checksum: 309b81889459c9056d686910dd512bf9 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-07-12T19:50:05Z (GMT) No. of bitstreams: 1 FabioPimentaDeLira_DISSERT.pdf: 2588802 bytes, checksum: 309b81889459c9056d686910dd512bf9 (MD5) / Made available in DSpace on 2016-07-12T19:50:05Z (GMT). No. of bitstreams: 1 FabioPimentaDeLira_DISSERT.pdf: 2588802 bytes, checksum: 309b81889459c9056d686910dd512bf9 (MD5) Previous issue date: 2015-11-30 / O presente estudo trata de uma an?lise, em car?ter experimental, do consumo de combust?vel de um veiculo flex, operando com diferentes misturas de gasolina e etanol em tr?fego urbano, o que permite obter resultados mais condizentes com a realidade do motorista, haja vista que os ?ndices de consumo aferidos pelo INMETRO n?o levam em considera??o o real cen?rio que a popula??o enfrenta diariamente em seus deslocamentos urbanos, possibilitando assim a escolha mais economicamente vi?vel da mistura gasolina/etanol, acarretando numa redu??o dos custos e, possivelmente, uma diminui??o nos ?ndices de emiss?o de poluentes. Atualmente, os fabricantes de ve?culos flex recomendam o abastecimento com etanol, caso o valor deste n?o ultrapasse 70% do valor da gasolina comum, entretanto, os ve?culos com a tecnologia flex, possibilitam operar com qualquer percentual de mistura no tanque de combust?vel, por?m, hoje, muitos dos propriet?rios desses ve?culos n?o utilizam esse recurso com efici?ncia, por desconhecerem essa possibilidade de mistura ou pela raz?o de n?o existir um estudo mais profundo em rela??o ao percentual ideal da mistura que proporcione um maior rendimento com um custo inferior ao proposto pelos fabricantes. / This study is an analysis, on a trial basis, the fuel consumption of a Flex vehicle, operating with different mixtures of gasoline and ethanol in urban traffic, allowing more consistent results with the reality of the driver. Considering that most owners unaware of the possibility of mixing the fuel at the time of supply, thus enabling the choice of the most economically viable mixing gasoline / ethanol, resulting in lower costs and possibly a decrease in pollutant emission rates. Currently, there is a myth created by the people that supply ethanol only becomes viable if the value of not more than 70% of regular gasoline. However vehicles with this technology make it possible to operate with any percentage of mixture in the fuel tank, but today many of the owners of these vehicles do not use this feature effectively, because they ignore the possibility of mixing or the reason there is a deeper study regarding the optimal percentage of the mixture to provide a higher yield with a lower cost than proposed by the manufacturers.

Made available in DSpace on 2014-12-17T14:53:12Z (GMT). No. of bitstreams: 1 RosangelaLRS.pdf: 1607437 bytes, checksum: c3288cd109c72956dad50f3ce4abe494 (MD5) Previous issue date: 2006-05-19 / The objective of this work was to investigate the factors that inhibit the use of Environmental Techniques in the Gas Station of the city of Natal/RN. For this, a survey with the aid of a questionnaire was used like research instrument. It s used a sample for convenience, not probabilistic. For collection of the data, it was used directly application of the questionnaire to the Managers or Assistant managers of the gas station, in accordance with its availability or presence. The data was collected in all the regions of Natal (North, South, East and West). The population in accordance with the data of the ANP of September 2005 is of 111 ranks and the collected sample was of 86. To carry through the analysis of the data of this research had been used softwares Excel and Statistic version 5.0, for Windows. The analysis of data is divided in two parts; descriptive analysis and analysis of groupings (clusters). The results showed that bigger part of the interviewed ones has between 30 and 39 years of age; they have second grade completed; they had declared to have little between and reasonable knowledge how much to the use of Clean Technology (CT) in gas station; and a small part of the interviewed ones had informed to have much knowledge how much the resolutions of the CONAMA established for the Gas Station. Of the searched ranks, the majority is national(76.7%); the most accurate practice environmental used in the gas station are: it collects selective of oil used or contaminated and ecological tanks - coated with strengthened fibre glass; great part of the interviewed ones (33.8%) informed that never the TL makes planning of referring future action; about of the half of the interviewed ones (84.9%) they had more declared that its employees have of none to a reasonable level of training for deal with problems that compromise the environment; the majority of the ranks (72.1%) functions has for more then six years. It is observed that almost all the interviewed ones (96.5%) evaluate as being important or very important the implantation of CT in Gas Station and the great majority (82.1%) evaluates the difficulty in if implanting these technologies in Gas Station as being easy or very easy. In the analysis of cluster, it was verified existence of two groupings (as much in the variable of the barriers and benefits), being that inside of each clusters exists homogeneity and between clusters exists heterogeneity. In reality, everything is important or very important in the opinion of the interviewed ones. There only exists a small significant difference that separates them in clusters / O objetivo deste trabalho foi investigar os fatores que inibem o uso de T?cnicas Ambientais nos Postos de Combust?veis da cidade de Natal/RN. Para isso, foi utilizado um procedimento de pesquisa do tipo Survey (levantamento) com o aux?lio de um question?rio, identificado como sendo o instrumento de pesquisa. Utilizou-se a amostra por conveni?ncia, n?o probabil?stico. Para coleta dos dados, utilizou-se a aplica??o do question?rio diretamente aos Gerentes ou Sub-gerentes dos Postos, de acordo com a sua disponibilidade ou presen?a. Os dados foram coletados em todas as regi?es de Natal (Norte, Sul, Leste e Oeste). A popula??o de acordo com os dados da ANP de Setembro 2005 ? de 111 postos (atualizados) e a amostra coletada foi de 86. Para realizar a an?lise dos dados desta pesquisa foram utilizados os softwares Excel e Statistica vers?o 5.0, para Windows. A an?lise de dados ? dividida em duas partes: an?lise descritiva e an?lise de agrupamentos (clusters). Os resultados mostraram que maior parte dos entrevistados t?m entre 30 e 39 anos de idade; t?m 2? grau completo; declararam ter entre pouco e razo?vel conhecimento quanto ao uso de TL em postos de combust?vel; e uma pequena parte dos entrevistados informaram ter muito conhecimento quanto as resolu??es do CONAMA estabelecidas para os Postos de combust?vel. Dos postos pesquisados, a maioria ? nacional (76,7%); as pr?ticas ambientalmente corretas mais usadas nos postos s?o: coleta seletiva de ?leo usado ou contaminado e tanques ecol?gicos - revestidos com fibra de vidro refor?ada; grande parte dos entrevistados (33,8%) informou que nunca fazem planejamento de a??o futura referente a TL; cerca de mais da metade dos entrevistados (84,9%) declararam que os seus funcion?rios t?m de nenhum a um razo?vel n?vel de treinamento para lidarem com problemas que comprometem o meio ambiente; a maioria dos postos (72,1%) funcionam h? mais de 6 anos. Observa-se que quase todos os entrevistados (96,5%) avaliam como sendo importante ou muito importante a implanta??o de TL em Postos de combust?vel e a grande maioria (82,1%) avalia a dificuldade em se implantar essas tecnologias em postos como sendo f?cil ou muito f?cil. Na an?lise de cluster, verificou-se a exist?ncia de dois agrupamentos (tantos nas vari?veis das barreiras e benef?cios), sendo que dentro de cada clusters existe homogeneidade e entre clusters existe heterogeneidade. Na verdade, tudo ? importante ou muito importante na opini?o dos entrevistados. Existe apenas uma pequena diferen?a significativa que os separa em clusters

Made available in DSpace on 2014-12-17T14:58:13Z (GMT). No. of bitstreams: 1 JoseCTN_DISSERT.pdf: 3330335 bytes, checksum: 998a47f5aaa9275ec35cf7e52cf1d08e (MD5) Previous issue date: 2012-03-16 / This work presents the analysis of data collected by Universidade Federal do Rio Grande do Norte and State Public Prosecution Office experts concerning to current situation of liquid fuel resale stations, its forms of storage and its technical apparatus for the performance of primary functions (supply of vehicles) and secondary (car washing, storage of used oil, oil change etc.). The data presented were analyzed in the setting of the city of Natal (RN) and considering its characteristics, potentialities and weaknesses. Thereafter, it was discussed liquid fuels resale pollution potential in the city and legal provisions directed to implementation of Green Seal. The discussion involves three agents: environmental, legal and technical ones, applied to all 110 resale fuel stations which were analyzed / Este trabalho apresenta a an?lise dos dados colhidos pelos peritos da Universidade Federal do Rio Grande do Norte e do Minist?rio P?blico Estadual referentes ? situa??o dos postos de revenda de combust?veis l?quidos, suas formas de armazenamento e o seu aparato t?cnico para o exerc?cio das fun??es principal (abastecimento de ve?culos) e secund?ria (lavagem de ve?culos, armazenamento de ?leo usado, troca de ?leo etc.). Os dados apresentados foram analisados sob a configura??o da Cidade de Natal (RN) e levando-se em considera??o suas caracter?sticas, potencialidades e fragilidades. Da? por diante, discutiu-se sobre o potencial poluidor da atividade de revenda de combust?veis l?quidos na cidade e as disposi??es legais direcionadas para a implanta??o do Selo Verde. A discuss?o apresentada envolve principalmente tr?s agentes: o ambiental, o legal e o t?cnico, aplicados aos 110 postos de revenda de combust?veis analisados