Current Issue : January - March Volume : 2018 Issue Number : 1 Articles : 5 Articles
It has been known that magnetic exposure of fuel prior to combustion\ncan improve effectiveness of combustion process. However, the main reason of\nthe phenomenon is still unclear. In this paper, characteristics of fuel as exposed to\nelectromagnetic field was measured experimentally and inter-related appropriately\nin order to have preliminary insight to the clarification of the phenomenon. Fuel\ncharacteristics being investigated were viscosity, vibration of the fuel molecules,\ndipole moment, and refractive index. These experiments were performed using various\nblend compositions between fossil diesel (petrodiesel) and biodiesel fuel i.e. B0,\nB10, B40, B70 and B100. The electromagnetic field was generated by a galvanum\ntube wounded with 9,000 wire coil. The fuel characteristics of both prior and post\nelectromagnetic exposures were then measured with time variation of 0ââ?¬â??1,800 s.\nThe experimental results revealed that electromagnetic exposure of the fuel increased\nvibrational frequency of its molecules significantly, which in turn weakened\nthe attracting energy and caused uniform arrangement of dipole moment of the\nmolecules. The experimental data also revealed that the fuel characteristics did not\nalter significantly after it was exposed to the electromagnetic field for more than 1,200 s. This information is considered to be useful for further research in order\nto resolutely clarify the phenomenon of efficient combustion process of fuel after\nexposure to magnetic field....
The continuous improvements in micro-forging technologies generally involve process,\nmaterial, and tool design. The field assisted sintering technique (FAST) is a process that makes\npossible the manufacture of near-net-shape components in a closed-die setup. However, the final part\nquality is affected by the influence of friction during the ejection phase, caused by radial expansion\nof the compacted and sintered powder. This paper presents the development of a pre-stressed tool\nsystem for the manufacture of micro gears made of aluminum. By using the hot isostatic pressing\n(HIP) sintering process and different combinations of process parameters, the designed tool system\nwas compared to a similar tool system designed without a pre-stressing strategy. The comparison\nbetween the two tool systems was based on the ejection force and part fidelity. The ejection force was\nmeasured during the tests, while the part fidelity was documented using an optical microscope and\ncomputed tomography in order to obtain a multi-scale characterization. The results showed that the\nuse of pre-stress reduced the porosity in the gear by 40% and improved the dimensional fidelity by\nmore than 75% compared to gears produced without pre-stress....
Heat exchangers are devices in which heat is transferred from one fluid to another\nfluid as a result of temperature difference. Heat exchanger presented in\nthe current paper in which inside the tubes flows water, but outside the tubes\nflows air aims to enable cooling of circulating water, which serves to cool the\nengine of a machine. Such exchangers find application in the automotive industry\nas well as heating and cooling equipment and HVAC systems etc. The\nsurface of the heat exchanger by the air side always tends to be much larger\nusing surface fins in order to facilitate equalization of thermal resistance for\nboth sides of the heat exchanger, because the rate of transmission of heat from\nthe water side is much greater. Furthermore, the paper will present analytical\nand experimental studies involved for determination of performance of\nplate-fin heat exchanger for various flows of working fluids in order to get the\nhighest values of performances i.e. : overall heat transfer coefficient U, efficiency\nof heat exchanger , maximal and real heat transferred, pressure drop,\nair velocity and Reynolds number from the air side of heat exchanger etc. The\npresent scientific paper is based on the fact that from the experimental model\nmade for laboratory conditions, conclusions are derived that can be used\nduring installation of such heat exchanger on certain machines in order to\npredict their performance....
The combined effects of preexposure to high temperature and alkalinity on the tensile performance of structural GFRP reinforcing\nbars are experimentally investigated. A total of 105 GFRP bar specimens are preexposed to high temperature between 120âË?Ë?C and\n200âË?Ë?C and then immersed into pH of 12.6 alkaline solution for 100, 300, and 660 days. From the test results, the elastic modulus\nobtained at 300 immersion days is almost the same as those of 660 immersion days. For all alkali immersion days considered\nin the test, the preheated specimens provide slightly lower elastic modulus than the unpreheated specimens, showing only 8%\nmaximum difference.The tensile strength decreases for all testing cases as the increase of the alkaline immersing time, regardless\nof the prehearing levels. The tensile strength of the preheated specimens is about 90% of the unpreheated specimen for 300 alkali\nimmersion days. However, after 300 alkali immersion days the tensile strengths are almost identical to each other. Such results\nindicate that the tensile strength and elastic modulus of the structural GFRP reinforcing bars are closely related to alkali immersion\ndays, not much related to the preheating levels. The specimens show a typical tensile failure around the preheated location....
The deformation and failure of rock mass is a process of energy dissipation; the damping of DDA is a very important and basic\nproblem. The correctness and effectiveness of DDA rely on the appropriate values of the numeric controlling parameters like time\ninterval, spring stiffness, and assumed maximum displacement ratio ...
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