The main purpose of this research is to investigate the effect of various ball milling duration on the surface morphology, hardness and wear properties of nickel- quarry dust (Ni-QD) composite ...coating on aluminium alloy 6061 (AA6061) substrate. Ni-QD composite coatings were deposited on zincated AA6061 substrate by using electrodeposition technique. The quarry dust particles were prepared by ball milling process at 5, 10, 15 and 20 hours. Later, the quarry dust particles were added to nickel citrate bath at 50 g/l for electrodeposition of Ni-QD composite coating. The electrodeposition process was carried out for 1 hour at 40º C, under the current density of 3 A/dm2. X-ray Fluorescence (XRF), X-ray Diffraction (XRD) and scanning electron microscope (SEM) analyses were carried out in order to investigate the influence of ball milling duration on the prepared quarry dust as well as the produced composite coating. In addition, microhardness and wear testing of Ni-QD composite coatings were also performed in this study. The microhardness values of the nickel composite coatings using ball milled quarry dust are higher than using crushed quarry dust. The microhardness values for all nickel composite coatings produced from crushed and ball milled quarry dust increases from 190.6 to 282.2. The increase in microhardness values is due to the high density of quarry dust in the electrolyte. The damage of the wear scar was improved, as the ball milling duration increases from 0 to 20 hours.
A new physical model of the hosing instability that includes relativistic laser pulses and moderate densities is presented and derives the density dependence of the hosing equation. This is tested ...against two-dimensional particle-in-cell simulations. These simulations further examine the feasibility of using multiple pulses to mitigate the hosing instability in a Nd:glass-type parameter space. An examination of the effects of planar versus cylindrical exponential density gradients on the hosing instability is also presented. The results show that strongly relativistic pulses and more planar geometries are capable of mitigating the hosing instability which is in line with the predictions of the physical model.
This paper presents the result of pulsating lubrication strategy (PLS), an alternative metalworking fluids approach to improve machining performance. The formation of built-up edge (BUE) and built-up ...layer (BUL) is among the problems encountered during the machining of aluminum alloy, which degrades cutting performance and thus affects the machined surface quality. This study focuses on chip removal effectiveness by jetting a coolant intermittently of PLS on the cutting tool to create a hydraulic shock. The water stream coolant was set to pulsate at 2000 pulse/min with the pressure of 0.76 MPa. Applying this method improves chip evacuation. Hence, minimizing the formation of BUE and BUL more effectively than dry cutting.
Layered LiNi1-xCoxO2 cathode material, particularly LiCo0.6Ni0.4O2 (LCN) in stoichiometry is one of the promising cathode materials as it possesses a good electrochemical behaviour and performances ...comparable with commercial LiCoO2 (LCO) cathode material. However, more improvement needs to be done in LCN cathode material in terms of higher toxic Co content and higher cation mixing in the material which mainly contributes to the structural instability and affects the capacity fading of the material. To combat both significant issues in the material, the stability of that material structure needs to be tackled first. In this study, Co was partially substituted with Ti4+ to give the LiCo0.55Ni0.4Ti0.05O2 (LCNT) cathode material using the combustion method. To get the optimum condition of LCNT, the precursor was then calcined at a temperature of 750°C for 24 hours, 48 hours and 72 hours and denoted as LCNT24, LCNT48, and LCNT72 respectively. XRD reveals that all samples are pure, single-phase with no impurities present except for LCNT72. Nano-sized LCNT24 sample has the highest RIR value of 1.84 indicating the lowest degree of cation Li+/Ni2+ mixing in the material and the most stable structure compared to others.
Malaysia is active in automotive manufacturing activity for decades. The needs in continuing development of lean manufacturing tools are not exempt to be pressurised, which enable the regional demand ...for vehicles. Several research studies clearly indicate significant opportunities for efficiency improvement in the automotive industry through implementation and a higher level of lean management utilization. Apparently, there is still a small number of study for Lean Management Tools in a Malaysian Automotive Assembly Line. The emphasis for the study is to investigate practices of lean tools applied in the production line and proposing an implementation of lean management tools available to apply in the Malaysian automotive production line work practice. A review study of literature from different journal publication sources related to lean management tools was made to understand more on how to best identify practices of lean tools. From this literature study review, three lean management tools have been investigated and identified such as 5S, Value Stream Mapping (VSM) and Work Standardization are to be studied for proposed application in the Malaysian automotive assembly production line. The impact of implementing lean tools is studied based on the results gathered from previous studies related to 5S, VSM and Work Standardization. The conclusion of this paper is to investigate the practices and implementation of Lean Management Tools in the Malaysian Automotive Assembly. It is to be suggested that a future case study on the proposed lean tools using time study and observational survey to be implemented in Malaysian automotive assembly line and measuring the improvements gained from utilizing the selected lean tools. The result from this review is that among the lean tools highlighted here, 5S is applied everywhere in an automotive assembly line, supported by VSM with its overview of the whole process and also Work Standardization to standardize the method and flow of work in an assembly line and improve the consistency of work. Therefore, concluding this study would be the importance of 5S, VSM and Work Standardization as the implemented tools in an automotive assembly line, in view of overcoming the challenges of the constant change in customer demand.
Abstract
The purpose of this study is to understand the influence of four grasping techniques recommended by Saracen Archery and associated forearm muscles activation on traditional archer’s shooting ...performance. Each archer has shot 6 arrows in each grasping technique to the target, EMG activities of muscle Flexor Digitorum Superficialis (MFDS) and muscle Extensor Digitorum (MED) were collected in bow arm during aiming phase. The shooting performance was indicated by the distance from arrow hitting point on the target to the bull’s eye. The results revealed that each subject has specific grasping technique to obtain the best shooting performance. The grasping technique that generated the best performance is not as recommended by Saracen Archery. All subjects indicated that the best shooting performance was obtained when MED activated more than MFDS.
Non-noble metal supported catalysts such as 20NiO/MgO, 20CuO/MgO and 20ZnO/MgO were catalyzed the gasification of oil palm frond biomass in supercritical water for hydrogen production. All the ...catalysts are found to be pure with no impurities present. The specific surface area of these catalysts can be arranged in the order of 20NiO/MgO (30.1 m2 g–1) > 20CuO/MgO (16.8 m2 g–1) > 20ZnO/MgO (13.1 m2 g–1). Although catalysts with larger specific surface area are beneficial for catalytic reactions, in this study, the largest specific surface area did not lead to the highest catalytic performance. It is found that the 20ZnO/MgO catalyst (118.1 mmol ml−1) shown the highest H2 yield than the 20CuO/MgO (81.1 mmol ml−1) and 20NiO/MgO (72.7 mmol ml−1) catalysts. In addition, these supported catalysts also shown higher H2 selectivity with reached 83.8%, 84.9% and 87.6% for 20CuO/MgO, 20NiO/MgO and 20ZnO/MgO catalysts. Other factors such as dispersion, basicity and bond strength play more important roles in supercritical water gasification of biomass to produce hydrogen.
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•Catalytic SCWG using 20NiO/MgO, 20CuO/MgO and 20ZnO/MgO catalysts.•H2 yield and H2 selectivity: 20ZnO/MgO > 20CuO/MgO > 20NiO/MgO.•Specific surface area: 20NiO/MgO > 20CuO/MgO > 20ZnO/MgO.•Higher specific surface area not always leads to highest catalytic performance.
ZnO and Zn0.99Cu0.01O nanostructures were prepared by a simple sol–gel method. The band gaps of the materials were systematically studied based on the dependence of the dimensions of the ...nanostructures as well as the presence of a dopant material, Cu. ZnO and Zn0.99Cu0.01O nanostructures were found to exhibit band gap widening whilst substitution of Cu in the lattice of ZnO caused its band gap to narrow with respect to the pure ZnO materials. In order to understand the phenomenon of band gap change, structural, spectroscopic, particle size and morphological studies were done. The band gap change occurring when the materials were in the nanostructured phase was proven to be mainly due to the downward shift of the valence band. Interestingly, when the band gaps of the pure ZnO and Cu doped ZnO were compared, the band gap changes were due to different shifts of the valence bands.
As a result of its substantial energy density, layered LiNi0.8Co0.15Al0.05O2 cathode materials are thought to be the most promising of the next-generation cathode materials for electric vehicles ...(EVs). In this research, self propagating combustion (SPC) is used to prepare cathode materials made of pristine LiNi0.8Co0.15Al0.05O2 (NCA) and NCA doped with 1% Fe to produce LiNi0.8Co0.14Fe0.01Al0.05O2. Based on X-Ray Diffraction (XRD) results, pristine and doped NCA cathode materials were pure and single phase. Reference Intensity Ratio (RIR) values for pristine and doped NCA are 0.87 and 1.12 respectively indicating that the amount of cation mixing was reduced with Fe doping. Through Rietveld refinement, it was discovered that the addition of Fe to NCA resulted in a decrease in cation mixing from 13.56% to 4.07%.It was found that both pristine and doped NCA possessed polyhedral like shape morphology. It can be seen that doping with 1% Fe does not change much in the crystallite size of the materials. By having less cation mixing, Fe doped was found to greatly improve the structural integrity of NCA cathode materials, which in turn improved the materials’ electrochemical performance.
Zinc oxide nanostructures with vary pH have been successfully synthesize using a sol-gel method. The nanostructured materials were annealed at low temperature of 300 °C for 3 hour. The effect of pH ...of the synthesis condition of ZnO on the structural and optical properties of the nanostructures were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and UV-Vis spectrophotometer. XRD results revealed that only sample at very acidic condition was not pure with the presence of impurities. This implies that acidic condition require more energy in order to produce pure and single phase of ZnO nanostructures. FESEM results showed that at very acidic and basic condition, the crystallites tended to agglomerate to form bigger particles. The band gap energy of the ZnO nanostructures at pH 6 and 9 were 3.276 and 3.300 eV respectively. Interestingly, it was found that as the aspect ratio of nanorods increased, the band gap energy of the material also increased.
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