Journal Articles
Permanent URI for this collection
Browse
Recent Submissions
1 - 5 of 215
-
PublicationImpact of chilled air nozzle types on surface integrity in drilling of aluminum alloy 1050(Semarak Ilmu Publishing, 2024-07)Using cutting fluid in the machining process for Aluminum Alloy 1050 is advantageous as it helps mitigate the effects of temperature generated during cutting. It can shorten tool life and impair the quality of machine parts. Despite its benefits, cutting fluids has several disadvantages, such as high expenses, potential environmental harm, and user health risks. This research evaluates the effects of green cutting conditions, particularly nozzle types, on the metallurgical properties of the material. Their impacts on tool wear, X-Ray Diffractometer (XRD) pattern, Full Width at Half Maximum (FWHM), crystallite size, and hardness during the drilling process were investigated. The findings indicate that using chilled air with dual nozzles for cooling and lubrication is highly effective, resulting in less tool wear and a relatively purer crystalline structure of the material compared to other conditions. These results emphasize the importance of controlling cutting conditions, especially nozzle types, to produce high-quality parts with improved metallurgical properties.
-
PublicationSoft material drilling: a thermo-mechanical analysis of polyurethane foam for biomimetic bone scaffolds and optimization of process parameters using Taguchi method(Cell Press, 2024)Drilling is a widely employed technique in machining processes, crucial for efficient material removal. However, when applied to living tissues, its invasiveness must be carefully considered. This study investigates drilling processes on polyurethane foam blocks mimicking human bone mechanical properties. Various drill bit types (118° twist, 135° twist, spherical, and conical), drilling speeds (1000–1600 rpm), and feed rates (20–80 mm/min) were examined to assess temperature elevation during drilling. The Taguchi method facilitated systematic experiment design and optimization. Signal-to-noise (S/N) ratio and analysis of variance (ANOVA) identified significant drilling parameters affecting temperature rise. Validation was conducted through confirmation testing. Results indicate that standard twist drill bits with smaller point angles, lower drilling speeds, and higher feed rates effectively minimize temperature elevation during drilling
-
PublicationEffects of laser texturing on tribological properties and wettability of titanium nitride-coated AISI M2 high-speed steel(Elsevier, 2024)Excessive friction encountered during the sliding of mechanical pairs usually causes detrimental effects on both the component surfaces and their performance. Elevated contact stresses owing to high friction lead to increased wear and shortened service lifetimes. To mitigate this issue, this study explored a solution involving a surface modification of AISI M2 tool steel. The approach included a titanium nitride (TiN) coating and the laser texturing of a rectangular array of micro-dimples on the metal surface. The effect of laser texturing parameters on dimple size was investigated, and the use of 8-W laser power together with 0.1-second irradiation duration was able to fabricate the desired dimple size to enhance the lubrication. The influences of the dimple density on the coating adhesion, wettability, friction, and wear of laser-textured surface were also examined. The coating adhesions of the untextured and textured TiN-coated surfaces were not significantly different. The textured surface exhibited oleophilic behavior, and oil was more likely to spread on the surface with a higher dimple density. Under a load of 50 N, the surfaces with dimple densities of 5 % and 9 % exhibited low friction compared to the untextured surface. Wear was found to be low on the textured surface due to the enhanced lubricating effect and improved load-carrying capacity. Additionally, the empirically derived Archard wear coefficients showed non-linear wear behavior throughout the sliding length. The obtained results evidence that the laser texturing is feasible for improving tribological performance of the low friction-coated high-speed steel surfaces.
-
PublicationWake field interaction in 3D tidal turbine arrays: numerical analysis for the Pentland Firth(American Society of Civil Engineers, 2024)This study presents a methodology for applying the three-dimensional actuator disk-RANS technique in modeling tidal energy converters within a regional-scale simulation. Of particular interest are the robustness of the applied momentum source term and its effectiveness in modeling an array of full-sized tidal turbines under realistic hydrodynamic and operational conditions. The Inner Sound region, which is the site of commercial-scale deployment projects of the Pentland Firth in Scotland, is chosen as the study area. While the actuator disk approach had been used in past studies to parameterize the far-wake region of horizontal-axis tidal turbines, details of its three-dimensional implementation have not been thoroughly discussed. Criteria adopted in deciding the array location are presented in this study, along with the actuator disks' detailed setup and constraints. The models are subjected to one operational characteristic that is similar to commercial devices in service to examine the accuracy of the imposed source term under complex flow conditions. The results demonstrate that the thickness of the disk imposed in the source term has a pronounced influence on the model outputs. In addition to accurately modeling flow propagation and wake interactions, the models are also able to replicate the observed asymmetrical tidal currents in the region. Because there is currently limited published material on the detailed application of the actuator disk approach in ocean-scale models, this study is hoped to fill the research gap and provide evidence, guidance, and examples of best practices for future studies.
-
PublicationExperimental and numerical investigation of an innovative desalination unit under laminar, transient, and turbulent flow conditions(Elsevier, 2024-07)Solar-based desalination systems face problems such as interruptions in the supply of solar energy or insufficient levels of available solar energy due to geographical or weather conditions, which results in a drop in system performance. To overcome this issue, this study proposes a novel concentrating solar-powered flash desalination system with pressure modulation. The objective of this research is to investigate the influence of flow rate and perform energy and exergy analyses for the proposed novel device. The feed flow rate varied in the range of 0.2–1 L/min. The results revealed that the distillate production increases to an optimum as the flow rate is augmented. The highest product water output of 8880 ml/h was observed at a turbulent flow of 0.8 L/min. The brine heater exhibited an average energetic efficiency of 32 %. Additionally, the flash chamber, brine heater, and condenser exhibited average exergy efficiencies of 32.8 %, 4.1 %, and 89.2 %, respectively. The device achieved the lowest energy consumption of 100.8 kWh/m3, the highest gain output ratio of 15.5, and the highest energy utilization factor of 4.8. The present findings will assist engineers and researchers in analyzing the impact of feed rate on renewable energy-based desalination devices.