This research aims to develop parts for Advanced Fuel/Oil Filtering Re- circulation applicable to this kind of regulation proof engines. These parts can play a role of converting traditional air emission type crankcase into recovery type crankcase so that the engine can deal with environmental regulations, which do not allow minimal amount of toxic gas discharge. For the experiment, test method and specially made testing equipment are prepared. The results showed that Oil separation efficiency of the Cyclone type crank case oil separator was higher than one of the partition wall type in bench test and that Emission gas of the cyclone type oil separator was higher than one of the partition wall type in vehicle test.
Numerical simulation has been carried out to analyze seawater flow characteristics for shroud geometry variations with tidal current generation turbine. Seawater flow field characteristics in the turbine system are largely influenced by the shroud geometry. The vortex flow area in the diffuser part of the shroud gradually grows with the increase of shroud angle, but its recirculation velocity gets smaller. The centerline velocity of shroud increases with the length of cylinder part when diffuser part length and angle are constant(2.5m, 0.733rad) for the cylinder-diffuser type shroud system. Seawater velocity on the tip of turbine blade is pretty high, and as radial distance increases from the turbine axis, there is more gap between the fluid velocity isolines. These results in this study will be applicable for optimal design of tidal current generation system.
The automotive speaker is modeld to nonlinear speaker model using the large signal performance measurement. In order to study the characteristics for the mass of cone paper and damper, the mass of the cone paper and damper is changed and the nonlinear parameters of the speaker are studied using the experimental approach. From measurement data, the effect on force factor, compliance(stiffness), resonance frequency, Q-factor is investigated by changing the conpaper and damper.
In this article, we proposed a novel technique to fabricate cell‐culturing scaffold, that is, the hollowcylinder‐ grain assembly technique. This technique uses hollow cylindrical particles with sub‐mm thickness. Firstly, we fabricate PCL (polycaprolactone) hollow cylinder with sub-mm thickness using lab-made stainless steel mold. After that, we put the above-mentioned fabricated particles into a metal mold of which temperature could be controlled with hot plate and heat insulation system. PCL particles in the metal mold could be assembled together without severe collapsing under adequate temperature and time. Consequently, we could fabricate scaffold or foam structure with interconnected‐porosity and observed surface of cross section of fabricated scaffold by SEM.
As vehicle technology becomes advanced, the vehicle ride quality is improved. Safety of automotive suspension system is influenced directly with quality ride of passenger. This study aims at the improvement of automotive shock absorbers. Static and vibration analyses are analyzed at car cushion buffer with spring force due to the weight movement of vehicle. The maximum equivalent stresses and strains are calculated and six different natural frequencies are applied with each mode of vibration. Maximum deformation vibration value is also derived by the condition of harmonic vibration. As the durability of advanced automotive shock absorber can be improved by applying this study result with the design of car cushion buffer. ride quality gets better and the damage can be prevented.
The demand of energy is increasing around the world due to the high dependency of our society on energy. So the worldwide recognition of the limited supply of fuels has led to a large scale effort in search of alternative energy sources. Biodiesel has been considered as an alternative fuel to the petroleum diesel in compression ignition engines and is receiving more and more attention. Biodiesel can be obtained by the transesterification of methanol with triglycerides, with glycerin as by- product. This paper introduces the transesterification reaction of lard oil with methanol in the presence of hexane as solvent and potassium hydroxides as catalyst. Different from other researches, a new method to analyze the reaction process in this research was developed by starting with the by-product, crude glycerin. This new method was verified and the effects of various parameters such as solvent, molar ratio of methanol to oil (3:1-12:1), catalyst concentration (0.5-4 wt%) on the traneseterification process were investigated. Molar ratio of methanol to oil was optimized and identified to be 8:1, catalyst concentration of 2 wt% with hexane as solvent and at a temperature of 57℃ were found to be optimum for the reactions. Under this condition for 4 hours, the production yield can be 96.95%.
In this study, a computational work to investigate the influence of a turbulent wake flow by a rectangular prism with different aspect ratio, which is installed at the inlet of a diffuser. The k-ω model was adopted to simulate the turbulence. The continuity and time averaged Navier-stokes equations were solved by a implicit finite volume scheme. The computational results are qualitatively well compared to existing experimental data by PIV. The results show that the velocity recovery of the subsonic diffuser is dependent on the aspect ratio of rectangular prism.
This experimental study was performed to investigate wake flow and unsteady flow characteristics using a model for actual shape of a wind breaker and visualization of flow through the particle image velocimetry. Three control angle of flap were selected and instantaneous velocity distributions and flow characteristics were experimently investigated. It is found that as the control angle increases, the flows are characterized by the appearance of the growth of recirculation region.
Most of the plastics products have been manufactured by injection molding. Molding trouble in injection-molded parts is caused by changing a molding product and molding process condition, etc. In this study, warpage in the injection molded part have been studied. specimens are rectangular flat shape with and without ribs. Non-crystalline resins (PC) and crystalline resins (PA66) were used for material and 30% glass fiber reinforced-resins(PC, PA66). Flat shape ribs showed higher warpage than flat shape without rib by 10 to 41%. the specimens with ribs that are located parallel to flow direction has higher warpage than the specimens with rib that are located perpendicular to flow direction by 11 to 50%. crystalline resins have higher warpage than non-crystalline resins by 22 to 78%.
High hardness steel generally means its hardness over HRC45. This using CBN tools for turning. Tool breakage and damage during turning process cause material loss and additional tool cost. If it is predicted during the process and accumulate this data as a turning parameter it will be of help to turning mechanism understanding. For this purpose neural technology give beneficial as prediction, categorization, searching and enable nolinear function for pre-diagnosis algorithm. In this study we appraise the accuracy of prediction by applying backpropagation neural networks (BPNs) method in the high hardness steel turning.