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.

Made available in DSpace on 2015-03-13T17:08:35Z (GMT). No. of bitstreams: 1 MariaFCFS_ate_pag40.pdf: 3744773 bytes, checksum: 4daab562ea3330bc9c11745e39483ee7 (MD5) Previous issue date: 2006-05-19 / This study deals with origin, sedimentary filling and fossil content of three tanks situated at Ant?nio Martins, Barcelona, Rui Barbosa, and Apodi counties, Rio Grande do Norte State. In addition, fossil materials from the C?mara Cascudo Museum - UFRN - Funda??o Amigos do Lajedo Soledade - FALS, and from private ownership were investigated. The following families were identified: Megatberiidae, Gomphotheriidae, Mylodontidae, Equidae, Felidae, Canidae, Hydrochoeridae, Camelidae, Cervidae, Dasypodidae, Glyptodontidae, Macraucheniidae, Toxodontidae, and an undetermined Edentata Pilosa. The megafauna analysis indicated that herbivorc families occur mainly in tanks, whereas carnivore families occur in a vast proportion in an investigated ravine. Taphonomie analyses were limited to physical features because the vast majority of fossils were previously colleted without appropriate care for this kind of study. The main fossization processes were identified during diagenetie investigation. Permineralization is the most important process and replacement is the secondary one during fossilization. The study concluded that paleoenvironmental conditions during the late Pleistocene were more humid than the current one. Tropical savana, characterized by fields and cerrados , was the dominant vegetation / Neste trabalho s?o abordados alguns aspectos sobre os processos de forma??o, o preenchimento sedimentar e sobre o conte?do fossil?fero de tr?s "tanques" localizados nos munic?pios de Ant?nio Marfins, Barcelona, Rui Barbosa, e de uma ravina localizada em Apodi, todos no Estado do Rio Grande do Norte. Al?m do material fossil?fero coletado durante as etapas de campo foram tamb?m estudadas algumas pe?as pertencentes ao Museu c?mara Cascudo/UFRN, a FALS (Funda??o Amigos do Lajedo de Soledade) e tamb?m sob guarda pm1icular. Foram identificadas as fam?lias Megatheriidae, Gomphotheriidae, Mylodontidae, Equidae, Felidae, Canidae, Hydrochoeridae, Camelidae, Cervidae, Dasypodidae, Glyptodontidae, Macraucheniidae, Toxodontidae e de um Edentata Pilosa lndetetminado. A an?lise de megafauna presente nos diferentes dep?sitos mostrou que nos tanques predominam as formas herb?voras, enquanto que a representa??o coletada na ravina ? mais diversificada, incluindo tipos diferentes de carn?voros. Observa??es tafon?micas foram limitadas aos aspectos f?sicos observ?veis em laborat?rio, pois a grande maioria dos f?sseis j? havia sido coletada, sem que fossem observados os cuidados m?nimos indispens?veis a esse tipo de estudo. Os estudos diagen?ticos permitiram a identifica??o dos principais processos de fossillza??o: sendo a permineraliza??o o processo de preserva??o predominante, ocorrendo subordinadamente substitui??o. A interpreta??o das condi??es paleoambientais necess?rias para dar suporte as fam?lias identificadas, conduziu a infer?ncia de condi??es clim?ticas, durante o Pleistoceno superior, diferentes das atuais, mais ?mido com vegeta??o semelhante a de uma savana tropical, onde estariam presentes campos e cerrados