• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Influência da temperatura de alimentação de biocombustíveis no desempenho de motor agrícola / Analysis of the Influence of Fuel Temperature on the Diesel Engine Motor Performance

Gralick, Jonas 16 March 2018 (has links)
Submitted by Edineia Teixeira (edineia.teixeira@unioeste.br) on 2018-09-26T14:00:43Z No. of bitstreams: 2 Jonas_Gralick2018.pdf: 2685574 bytes, checksum: b64c2c6e6adf79c04cc4638b8d97ae16 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-09-26T14:00:43Z (GMT). No. of bitstreams: 2 Jonas_Gralick2018.pdf: 2685574 bytes, checksum: b64c2c6e6adf79c04cc4638b8d97ae16 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-16 / A search for alternatives to reduce the use of diesel within the national energy unit has been studied in a gradual way with biodiesel inserts to diesel, in order to reduce greenhouse gases. This is the result of the implementation of Law 13.263 / 2016, which is a mandatory addition of biodiesel in diesel, which is 15% in 2019. Parameters such as viscosity change when biodiesel is added to diesel, where this factor direct influence on fuel atomization and limitation in an engine. Thus, this work sought the behavior of renewable biofuels in a 61 cv agricultural engine, operating with blends of diesel, biodiesel and ethanol, which was tested on pure diesel and the proportions of 8, 15 and 20% biodiesel diesel, with and without ethanol, heating at 45, 65 and 85 ° C. The mechanical performance of the engine was measured by a eddy current dynamometer, and as gas emission by means of a combustion analyzer. The performance tests were performed on five replicates, while the submissions were done at a single time for each treatment. Regarding the performance of the engine, the specific weight was B0E1 at 85 ° C, while for the hourly consensus the lowest value was for the B20 at 85 ° C. The maximum power values were at 45 ° C, and the mixtures with the temperature level increased to the temperature of B15 at 85 ° C, 65 ° C. Rising fuel temperature, reducing heat, fuel temperature, reducing fuel temperature, reducing fuel temperature and reducing fuel consumption / A busca de alternativas para a redução do uso de diesel dentro da matriz energética nacional, tem sido estudada de modo gradativo com inserções parciais de biodiesel ao diesel, de modo a reduzir os gases de efeito estufa. Essa prática é decorrente da implantação da Lei 13.263/2016, que prevê a obrigatoriedade da adição do biodiesel no diesel, a qual chegará em 15% em 2019. Parâmetros como a viscosidade se alteram quando o biodiesel é adicionado no diesel, em que esse fator influencia diretamente na atomização do combustível e emissões em um motor. Assim, este trabalho buscou avaliar o comportamento de biocombustíveis renováveis em um motor agrícola de 61 cv, operando com misturas de diesel, biodiesel e etanol, o qual foi ensaiado o diesel puro e misturas nas proporções de 8, 15 e 20% de biodiesel adicionados ao diesel, com e sem etanol, aquecidas a 45, 65 e 85°C. O desempenho mecânico do motor foi medido por um dinamômetro de correntes de Foucault, e as emissões de gases foram mensuradas por um analisador de combustão. Os ensaios de desempenho foram realizados em cinco repetições, enquanto que as emissões foram coletas em uma única vez para cada tratamento. Em relação ao desempenho do motor, o menor consumo específico foi de B0E1 a 85°C, já para o consumo horário o menor valor foi para B20 a 85°C. Os maiores valores de potência máxima foram a 45°C, e as misturas com etanol também foram superiores em relação às misturas sem etanol, para os valores de torque houve um decréscimo com o aumento da temperatura sendo o menor valor para B15 a 85°C, porém essa mesma mistura teve melhor desempenho a 65°C. Para as emissões apresentou-se um aumento de O2 e temperatura dos gases de exaustão, em função do aumento da temperatura do combustível, todavia para os valores de CO2, NOx e eficiência de combustão teve um decréscimo em função do aumento da temperatura do combustível.
2

Influence de l’avancement de la mandibule sur la posture générale : étude stabilométrique et compléments électromyographiques

Bazert, Cédric 16 December 2008 (has links)
Les orthèses de propulsion mandibulaire sont fréquemment utilisées en orthopédie-dento-faciale pour stimuler le développement de ce maxillaire. Le déplacement antérieur de son centre de gravité et les tensions musculaires et viscérales (appareil aéro-digestif) qui apparaissent alors sont susceptibles d’influer sur la posture du sujet debout. Pour le déterminer, une étude stabilométrique a été menée. Elle permet de mettre en évidence les variations de position de la projection au sol du centre de gravité du corps (PGv). Les effets du port de trois orthèses imposant une quantité de propulsion différente ont été analysés, comparés entre eux et à la situation sans orthèse portée. Ces résultats ont été complétés par ceux issus d’une étude électromyographique, menée pour détecter les muscles mis en jeu dans le contrôle de l'équilibre. L’ensemble de ces expérimentations montre principalement une perte du contrôle postural (augmentation des oscillations de PGv) et un repositionnement plus postérieur du centre de gravité corporel lors d’avancement mandibulaire important, et ce d’autant plus que l’orthèse portée provoque peu de désocclusion inter-maxillaire. Une activité accrue des muscles fléchisseurs dorsaux du pied, de la hanche, du cou et extenseurs du rachis lombaire accompagne ces variations de position de PGv. Une hypothèse d'adaptation posturale en réaction à l'avancement de la mandibule est formulée ainsi qu’une critique et une évolution du protocole d’étude. / Mandibular propulsion splints are frequently used in dento-facial orthopedics so as to stimulate the development of this maxilla. Consequently, we can notice that its centre of gravity moves forward but also that visceral (the aerodigestive apparatus) and muscle tensions appear. These elements are likely to have an influence on the position of a person standing. A stabilometric study was carried out to highlight the changes in the projection onto the ground of the body centre of gravity (PGv). We analysed and compared the effects of the wearing of three different splints (each of which required a different level of propulsion). But a comparison between these results and the normal situation (no splint worn) was also drawn. Moreover, an electromyographic study was carried out to find out which muscles were stimulated in the balance control. Its results were then added to those of the stabilometric study. These experiments mainly show that we lose control of the postural equilibrium (increase of the PGv oscillations). It also shows that when the mandible is significantly moved forward, the body center of gravity goes back into a more posterior position. This is all the more true as the splint worn does not cause much inter-maxillar disocclusion. The back flexor muscle of the foot, of the hip, of the neck and the extensor muscle of the lumbar rachis are greatly stimulated in the variations of the PGv. A postural adaptation to the mandibular advancement is hypothetically expressed, together with a criticism and an evolution of the study procedure.

Page generated in 0.037 seconds