Applied Mechanics and Materials Vols. 465-466

Abstract: Particle Swarm Optimization (PSO) algorithm is often used for solving RFID Network Planning (RNP) problems. However, the direct correlation between RNP parameters (coordinates and power settings of RFID readers) and PSO solutions is rarely shown. This is due to the fact that most researches done in this field focus more on the development of new variants of PSO and the optimization result. For that reason, this paper tends to investigate the correlation between RNP parameters and PSO solutions. One of RNP objectives (Optimal Tag Coverage) is taken as an example. The formula of optimal tag coverage is elaborated in order to expose the allocation of RNP parameters in the formula. In addition, a representation system for embedding RNP parameters in PSO solution is explained. This paper can also serves as an early guideline for solving RNP problems using PSO algorithm.

Abstract: In metal injection molding, to identify the homogenous aluminum based feedstock is a challenging issues. In this study, a metal injection molding of aluminum feedstock which contains of high density polyethylene, stearic acid and paraffin wax as binder system was performed. The feedstock are used to produce tensile and gear shape green specimens using injection molding machine. The process ability of the metal injection molding feedstock depends on different parameters such as their binder composition and amount of metal powder used. From this study, the percentage of volume shrinkage experienced a sudden increase at the metal composition more than 50%. It also shown that, the paraffin wax content, affects the feedstock performances.

Abstract: In this research, Palm Oil Methyl Ester (PME) was added to methanol-biodiesel fuel in order to reduce the emissions. Thus, for diesel engines, alcohols are receiving increasing attention because they are oxygenated and renewable fuels. Therefore, in this study, the effect of PM emission level of a four cylinder, naturally aspirated, indirect injection diesel engine has been experimentally investigated by using methanol-blended diesel fuel from 0% to 20% with an increment of 5%. Thus, the effects of methanol on particulate matter (PM) components, soluble organic fraction (SOF) and dry soot (DS) using different type of fuel blends were investigated. Using a composite filter, the ester-methanol-diesel characteristic such as mass concentration in term PM, SOF and DS were analyzed under different engine operating conditions. The results show that the combination of 10% of methanol with 20% of Palm Oil Methyl Ester gives less PM emissions. Thus, PME20M10 of methanol-biodiesel fuel can reduce the PM emissions effectively for all load condition.

Abstract: A green technology of acoustic of fluid-structure interactions become an emerging technology today, a call thermoacoustic heat engine. Thermoacoutics heat engine systems convert the energy on a harvesting from a waste heat energy and convert to an electrical energy. That component of devices a call a hot heat exchangers. This paper study was focused on a new design of thermoacoustics heat exchanger and investigation of its performance in terms of thermal analysis. A conceptual design was produced with three designs of hot heat exchangers, which are wire-type, finger-type and star-type. Commercial code ANSYS-CFX software are used on the evaluation, the heat exchanger’s designs were simulated with two thermal conditions which are steady state and transient heat conduction. Materialselection from copper and aluminium a chosen to look-out the engagement between theoretical and numerical study. There are three inlet temperatures that are assumed will be supplied by constant waste heat which are 200°C, 350°C and 500°C.The star-type design has the highest value of heat conduction through a fin heat conduction with copper as a material which is 32.84W. Star-type hot heat exchanger recorded the fastest time to distribute temperature compared to wiretype and fingertype heat exchanger. Result shown the combination between star-type design and copper material will produce a good agreement to design a hot heat exchanger.

Abstract: A mechanical parking brake is one of the most important safety subsystems in a vehicle. Its main function is to hold a vehicle in position when parks on a flat or slope road. A typical problem of the mechanical parking brake system is that it requires a driver to apply sufficient or sometimes high pulling force to keep the vehicle stationary at any road slopes. Insufficient pulling force may cause the vehicle to move away or known as rollaway phenomenon. In order to overcome such an issue, an electro-mechanical parking brake (EMPB) is proposed and developed. The EMPB system is then tested using in-house parking brake test bench. It is found that the EMPB takes within 0.6s to fully engage and within 0.5s to disengage the system, respectively at 11.3 degrees of the road slope. Thus, current design of an EMPB system can prevent rollaway problem and also can be used as alternative replacement for the existing fully mechanical parking brake system.

Abstract: In recent years, a lot of effort has gone into many researchers making components of specific functions, mimicking various microstructures in nature. In this study, a super hydrophobic surface on injection-molded liquid silicone rubber was fabricated, mimicking micro-bumps on a lotus leaf. Original patterns were machined by electric discharge machining and liquid silicone rubber was injection-molded by using the original patterns as molds. The hydrophobic characteristics of injection-molded liquid silicone rubber surface replicated from the original electric discharge machined surface were studied. According to variations of injection molding process parameters like mold temperature, injection speed, injection pressure, vacuum, etc. the variations of water contact angles, as a hydrophobic index, measured on the injection-molded surfaces were examined. The liquid silicone rubber surface molded from wire-cutting electric discharge machined surface at mold temperature 120°C, injection speed 5 mm/sec, injection pressure 70 bar and in a vacuum cavity showed water contact angle of 148°, which is close to super-hydrophobic level.

Abstract: is present project investigated the impact penetration response of woven jute fiber reinforced composites subjected to wide range of low impact velocities. Hand layout woven jute fibers are thermally compressed to ensure no internal defects formed in the composites. Six layers of woven jutes are stacked together using different fiber orientations [0/q/0]_s. Low impact velocities are used ranging between 5 – 20 m/s. Force-time, force-displacement and energy-time curves are obtained automatically during the impact tests. The results are then discussed with considering the composite fragmentations and failure mechanisms. It is found that 0⁰ composite orientations capable to absorb sufficiently impact energy for 5 m/s but not for velocity greater than 10 m/s. When fiber orientations used between 15 – 45⁰, the composite impact resistance increased indicating two significant peak forces. These peak forces represent different type of failure mechanisms occurred during the striker progresses.

Abstract: Zinc oxide nanoparticles were successfully synthesized using modified gel combustion synthesis route. Zinc nitrate was used as oxidant while fatty alcohol (8 carbon chains octyl alcohol) and fatty ester (12 carbon chains lauric acid) derived from palm oil as well as glycerol played the role of organic dispersants/fuel. X-ray diffraction (XRD) patterns of the calcined samples exhibited three prominent peaks at ca. 2θ = 31.9°, 34.6° and 36.4° corresponding to (100), (002) and (101) reflection planes which were well indexed to zinc oxide hexagonal phase with wurtzite structure. Additional peaks were not observed in XRD patterns suggesting that no other phases were formed during the combustion synthesis. The morphology of calcined samples produced using glycerol as fuel exhibited elongated spindle-like shapes at ca. 1 μm consisted of nanoparticles. Samples prepared using fatty alcohol as fuel exhibited hexagonal morphology with crystallites sizes of ca. 30 to 40 nm. These results suggested that palm oil derived fatty alcohols and fatty esters are alternative materials as organic dispersants in the production of metal nanoparticles using gel combustion synthesis. The resulting optical properties of ZnO nanocrystallites prepared in this study were similar to those obtain from bulk materials with energy band gap value at ca. 3.28 eV compared to 3.37 eV for the latter.

Abstract: An experimental investigation had been carried out for heating-only on samples of type 304 stainless steel with oxyacetylene gas flame set to neutral flame with temperature 2700⁰-3300°C. The flame effect on surface integrity was investigated in terms of hardness test and microstructural characterization. Substrates temperatures were raised to 355°C as well as 550°C while oxyacetylene flame travels at approximate of 74 mm/min along the span of the material. The experimental outcome revealed the microstructures from two examined conditions: Initial grain structures as well as grain structure when flame heated to 355°C has retained austenite crystal structure while flame heating to 500⁰-550°C revealed chromium carbide precipitates. Within the investigated temperature range of 500⁰-550°C, preheating was evidently proven to result to sensitization.

Abstract: Welding fumes has both acute and long term chronic hazards. Small size welding workshops often have the drawback in health and safety consciousness. This study is conducted to investigate the personal welding fumes exposure among welders in small size welding workshop. Two workshops were selected to represent a very small welding workshop (2 workers) and a medium workshop (8 workers). The main activities in these workshops were metal inert gas welding (MIG) process onto mild steel material. Welding fumes was sampled for 8 hours and analyze by the inductively coupled plasma mass spectrometry (ICP-MS). The results of the study showed that only iron element existed notably in time weighted average (TWA) 8 hours calculation for both workshops. However, welding fumes exposure for both workshops were well below the permissible exposure limit (PEL) as stated in the Use and Standards of Exposure of Chemical Hazardous to Health regulation (USECHH) 2000 under the Malaysian Occupational Safety and Health Act 1994.