Applied Mechanics and Materials Vol. 315

Abstract: Journal bearing is widely applied in most of rotating machineries for transmission of large loads at mean speed of rotation. Friction caused by the shearing condition between journal, bearing and lubricant contribute to power loses in journal bearing system. In the present study, an experimental work was conducted to determine the effect of oil supply pressure on frictional force, friction coefficient and torque of a journal bearing. A journal diameter of 100 mm with a ½ length-to-diameter ratio was used. The oil supply pressure was set at three different values (0.3, 0.5, 0.7 MPa). Frictional force and friction coefficient results for 400, 600 and 800 RPM at different radial loads were obtained. It was observed that the change in oil supply pressure has affected the fluid frictional force and friction coefficient to some extent.

Abstract: Atherosclerosis (stenosis) is a common cardiovascular disease in which the blood vessel restructures by narrowing, thickening and gets hardened due to the deposition of plaque. A detailed study of narrowing of arteries applying computational aspects which leads to better findings in order to know the underlying mechanics of development and progression of such diseases. Such kind of analysis can be a useful tool for the medical professionals to study the realistic physiological conditions. They can simulate and observe the blood flow in arteries. In the present study, a case of normal and stenosed carotid bifurcation is simulated. The models are generated in CATIA based on the clinical data obtained from a patient using Ultrasound Doppler. A transient FSI analysis considering Newtonian behavior is performed to compare the significance of High Blood Pressure (HBP) and Normal Blood Pressure (NBP) on carotid bifurcation. The FSI simulation is carried out for both HBP and NBP conditions for several pulse cycles on normal and stenosed models using ANSYS13.0 to demonstrate the changes in flow behavior at various sections of the model. The computed results agree well with clinical observations and available literature as seen in case of NBP.

Abstract: This paper presents the development of wood-based composites material for 3D Printing process. The aim is to characterize the waste material from wood powder (WD) as an alternative material and low cost production for rapid prototyping product. The powder blends containing wood powder (90-120µm) with commercial ZP102 material from Z Corporation was used as the composite material. The materials were mechanically blended to produce composition of WD/ZP102(vol.%) 25:70, 50:50 and 75:25 respectively. The material was successfully processed on 3D printers machine, to produce three-dimensional components and followed by post-treatment with ZMax solution to enhance the mechanical properties. The mechanical properties, dimensional accuracy and surface quality of the components were evaluated and the results were compared with the standard ZP102 material. The result shows that the mechanical properties improved with the increased of wood powder content up to 50 (vol.%). However, dimensional accuracy and surface quality were decreased as the wood content increased. Further work on powder preparation is continued for surface quality improvement.

Abstract: Due to its versatility, micro metal injection molding has become an alternative method in powder metallurgy where it can produce small part with a minimal number of waste. The success of micro MIM is greatly influenced by feedstock characteristics. This paper investigated the characterization and optimization which both of them plays an important characteristic in determining the successful of micro MIM. In this paper, stainless steel SS 316L was used with composite binder, which consists of PEG (Polyethelena Glycol), PMMA (Polymethyl Methacrilate) and SA (Stearic Acid). The rheology properties are investigated using Shimadzu Flowtester CFT-500D capillary rheometer. The geometry of water atomised stainless steel powder are irregular shape, therefore it is expected significant changes in the rheological results that can influence the microcomponent, surface quality, shape retention and resolution capabilities. From rheological characteristics, feedstock with 61.5% shows a significant value with several injection parameters were optimized through screening experiment such as injection pressure (A), injection temperature (B), mold temperature (C), injection time (D) and holding time (E). Besides that, interaction effects between injection pressure, injection temperature and mold temperature were also considered to optimize in the Taguchis orthogonal array. Result shows that 61.5%vol contributes a significant stability over a range of temperature and the best powder loading from a critical powder volume percentage (CPVP) and rheological point of view. Furthermore interaction between injection temperature and mold temperature (BxC) give highest significant factor followed by interaction between injection pressure and mold temperature (AxC).

Abstract: LEV is a ventilation system that collects and sucks out particles such as dusts, mists, gases, vapors or fumes out of work station, so that they can’t be breathed in by occupants. There is a lot of LEV allocated and installed in order to help protecting occupants’ health but it doesn’t work properly. To overcome this issue, computational fluid dynamics (CFD) will be implemented. Past studies CFD techniques represent a very significant improvement of air ventilation systems. However, CFD is just a tool in prediction model, which can lead to inaccuracy of predicting airflow due to problems with pre-processing, solver and post-processing with parameter from actual experimental results. As of yet, it is not possible to 100% accurately simulate airflow around a body. These codes are simply models which are close to that of a real flow, but not an exact match. All of these require validation to help minimizing percentage error in CFD methodology. Several strategies are needed to boost effectiveness of LEV in terms of predicting airflow in a geometry model. The outcome of this research can be used as a benchmark or guideline for industries to help improving indoor air quality (IAQ).

Abstract: ndoor Air Quality (IAQ) problem mostly comes from improper maintenance of ducting. Monitoring of ducting were not widely practices since the awareness to maintain it will need consideration of budget. This paper examines the development of mechanical robot that can moveable across ducting to monitor ducting condition. The device expected to collect data such as Temperature (°C),, Relative Humidity (RH), gas pollutant and picture inside ducting. The result from this kind of monitoring should be a guide for proper maintenance activity. It also can predict necessary time and duration for duct cleaning. In conclusion, the mechanical robot data analysis that captured from ducting will be compared to the IAQ standard to create safe indoor air to the user or building occupants.

Abstract: The evaluation of catalytic combustion of waste palm trunk derived biomass and biochar with perovskite supported by K₂CO₃ using the TG (thermogravimetric) under oxidation atmospheres was carried out. Catalyst activity system of K₂CO₃ supported on perovskite was studied. The effect of using developed catalyst and reference catalyst in the catalytic combustion of waste palm trunk derived biomass and biochar was investigated. Catalysts, biomass and biochar waste palm trunk samples separated into the size of 100μm to 250μm fractions were subjected to non-isothermal thermogravimetric experiments were performed with different atmospheres which consisted of nitrogen and oxygen with N₂:O₂ 9:1 ratio, at heating rate of 2°C/min in the presence of 100cc/min total flow of N₂ and O₂. Alumina, K10Alumina and Ni10Alumina catalysts showed very poor catalytic combustion activity. However K10LMC82 or K₂CO₃/LaMn_0.8Cu_0.2O₃ catalyst showed better catalytic combustion activity compared to the other catalysts, which indicated that perovskite oxide was more effective as a support for the combustion.