863 resultados para Internal conbustion engine
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Includes bibliography
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Objective. This study aimed to investigate the stress distribution in screwed implant-supported prostheses with different implant-abutment connections by using a photoelastic analysis. Materials and methods. Four photoelastic models were fabricated in PL-2 resin and divided according to the implant-abutment connection (external hexagon (EH) and Morse taper (MT) implants (3.75 × 11.5 mm)) and the number crowns (single and 3-unit piece). Models were positioned in a circular polariscope and 100-N axial and oblique (45) loading were applied in the occlusal surface of the crowns by using a universal testing machine. The stresses were photographically recorded and qualitatively analyzed using software (Adobe Photoshop). Results. Under axial loading, the MT implants exhibited a lower number of fringes for single-unit crowns than EH implants, whereas for a 3-unit piece the MT implants showed a higher number of fringes vs EH implants. The oblique loading increased the number of fringes for all groups. Conclusion. In conclusion, the MT implant-abutment connection reduced the amount of stress in single-unit crowns, for 3-unit piece crowns the amount of stress was lower using an external hexagon connection. The stress pattern was similar for all groups. Oblique loading promoted a higher stress concentration than axial loading. © Informa Healthcare.
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Lubricating oils are crucial in the operation of automotive engines because they both reduce friction between moving parts and protect against corrosion. However, the performance of lubricant oil may be affected by contaminants, such as gasoline, diesel, ethanol, water and ethylene glycol. Although there are many standard methods and studies related to the quantification of contaminants in lubricant oil, such as gasoline and diesel oil, to the best of our knowledge, no methods have been reported for the quantification of ethanol in used Otto cycle engine lubrication oils. Therefore, this work aimed at the development and validation of a routine method based on partial least-squares multivariate analysis combined with attenuated total reflectance in the mid-infrared region to quantify ethanol content in used lubrication oil. The method was validated based on its figures of merit (using the net analyte signal) as follows: limit of detection (0.049%), limit of quantification (0.16%), accuracy (root mean square error of prediction=0.089% w/w), repeatability (0.05% w/w), fit (R 2 =0.9997), mean selectivity (0.047), sensitivity (0.011), inverse analytical sensitivity (0.016% w/w-1) and signal-to-noise ratio (max: 812.4 and min: 200.9). The results show that the proposed method can be routinely implemented for the quality control of lubricant oils. © 2013 Elsevier B.V. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Incluye Bibliografía
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Analiza los aspectos de reorganizacion interna necesarios para que la Oficina de la CEPAL para el Caribe funcione como Secretaria del CDCC (Comite de Desarrollo y Cooperacion del Caribe)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Includes bibliography
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Includes bibliography
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El analisis forma parte del proyecto IMIN, orientado a realizar investigaciones en profundidad sobre la migracion interna a partir de los ultimos censos de poblacion. El enfasis se situa en la descripcion del fenomeno en Guatemala, durante 1976-1981 y la poblacion bajo estudio es aquella nacida en Guatemala que vivio en el pais hasta la fecha del censo y 5 anos antes. Los migrantes son personas cuya residencia habitual en 1981 era distinta de aquella en 1976. Guatemala, Esquintla y El Peten son los departamentos de inmigracion por excelencia por ser la sede de la capital, y por su desarrollo agrario. Las mujeres se dirigen hacia el departamento de Guatemala, independiente del grupo etnico; la migracion es selectiva por edad y los grupos en que se producen los desplazamientos mayores se situan entre 15 y 24 anos. Las migrantes son algo menores que los hombres migrantes y los no indios migran mas que los indios; entre estos ultimos, predominan los hombres.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Information Paper, No 26