1,721,058 research outputs found
Experimental study of fatigue age on SUP-9 leaf spring steel which received heat treatment and shot peening processes
No full textOne aspect of the technical defect of leaf springs that are subjected to dynamic loads is fatigue defects which cause failure, as a result of uneven road surface or impact. Then leaf springs are expected to have a higher fatigue resistance limit. To improve the mechanical properties of leaf spring steel by providing heat treatment and shot peening processes, which will provide compressive residual stress to the surface, thereby improving the fatigue resistance of the spring. In this study, SUP 9 steel specimen has dimensions of 7 mm and a width of 50 mm, the heat treatment process is carried out at an austenitizing temperature of 920⁰C and 480 ⁰C temper temperature, for shot peening it is carried out at a pressure of 5 kg / cm², a shot diameter of 0.8 mm, with a peening time of 15 seconds, 17 seconds and 20 seconds, and testing of tensile, hardness, fatigue, residual stress, and fractography. This study shows that for a long shot time, good results are obtained, namely, the fatigue life has increased 8.7 times from the fatigue life of the spring steel without shot peening with application stress of 217 N / mm², and the residual stress is -847.39 N / mm²
Assessment of thermal energy storage integrated solar thermal collector system: a review
No full textRenewable solar energy is clean, abundant and globally available although intermittent in nature, thus requires storage ability whereby the solar radiation can be utilized and store simultaneously, the excess reuse during cloudy weathers and night time when there is no solar radiation. Continuous investigations by many researchers have shown that the integration of thermal energy storage (TES) to solar collector could improve the system performance and extend their utilization beyond solar radiation hours. Several studies utilizing different energy storage materials such as phase change materials (PCM), nanomaterials, PCM nanomaterials and hybrid PCM materials have reported improved heat transfer mechanism in solar thermal collectors. However, the demerits on weight, size and space increment, leakages and poor heat transfer mechanism caused by the PCM-TES incorporation with solar thermal collectors still persists despite the several research attempts on development of new smart PCM-TES materials and their incorporation. Thus far, the current mini-review paper attempts to bridge the literature gaps on past and recent PCM-TES integration techniques used for solar thermal collector systems. In addition, the performance analysis of existing designs, material fabrications and suggested improvement are discussed in this paper
Experimental studies on the quasi-static axial crushing behavior of foam-filled steel extrusion tubes
No full textThe concerns of automotive safety have been given special attention in order to reduce human fatalities or injuries. One of the techniques to reduce collisio
On three classes of mesh for the solution of a singularly perturbed two-point boundary value problem
No full textThere are several mesh types on which the solutions of discretized governing equations are obtained in computational fluid dynamics. Main classes include uniform, piecewise-uniform, exponential expanding, and hybrid meshes. Despite of their successful stories, their unwitting applications often result in bad solutions which involve, for instance, spurious oscillations, over- or under-estimations, and excessive computation time. This paper pays attention on three mesh classes, namely the uniform mesh, the piecewise-uniform mesh as represented by Shishkin mesh, and Shishkin-exponential expanding mesh which signifies the hybrid mesh. In particular, we examine the comparative effectiveness of the meshes for the solution of a singularly perturbed two-point boundary value problem. This is done by employing an error model based on the singular perturbation parameter and mesh number, with the assumption that the spatial error grows with respect to space. It is found that the number of mesh is reduced by at least half if the Shishkin mesh is replaced by the uniform and the Shishkin-exponential expanding meshes, in order to prevent spurious oscillations. The finding serves as a guideline for the researchers and engineers in selecting appropriate meshes on which flow problems are numerically solved
Development of an aquaponic system using ablution greywater for recreational purpose
No full textThe ablution ritual consumes large quantities of water, especially in mosques and public prayer rooms, where the greywater is allowed to run free and drain away. In Malaysia, most ablution system consists of a line of water taps with a drainage trough to carry the greywater to main drains. Some decent water is lost in the process as the tap is left running. In view of unnecessary waste, a simple recycling system can be designed to collect, treat and reuse the ablution water within a close-loop system for non-drinking applications, such as toilet flushing, general washing, plants watering and flowerbed cultivation. Therefore, this study was conducted to recover and reuse the ablution greywater that produced from Masjid Sultan Ibrahim with an aquaponic system. The aquaponic system involves the use of fish as a source of nutrients for the plant's growth, while the plants filter the water for the fish. In addition, the aquatic system model has its own attraction value that is very compatible with the landscape of the Masjid Sultan Ibrahim and at the same time it also provides recreational activities
Performance evaluation of a counter-rotating vertical axis wind turbine (VAWT) on a moving train
No full textRenewable energies are the types of energy that always exist and environmentally friendly. Wind energy is one of the renewable energy types that can reduce the mass use of fossil fuels as an alternative way to generate electricity. Practically, the Wind turbine is responsible for converting the kinetic energy as the wind act on the blades to generate electrical energy. In this study, the Savonius-type counter-rotating wind turbine has been chosen to study its aerodynamic performance on a moving train. For the simulation, the wind velocities tested start from 50 km/h until 160 km/h with 10 km/h interval between each case while investigating the performance in terms of torque and power output. The designs of the models are developed using Solidworks software and the Computational Fluid Dynamics (CFD) simulation software; ANSYS FLUENT was sued to run the simulations. The simulation results such as velocity streamlines, velocity contours, pressure contours and turbulent kinetic energy have been captured to allow the reader to observe the flow applied on the train as well as a wind turbine. The results obtained from the simulation show that the aerodynamic performance in terms of both power and torque output increases as the wind speed on the blades increases
Plasma transfer arc welding (PTAW) for depositing tungsten carbide-nickel cermet coating for corrosion
No full textPTAW is a cermet deposition method that may produce thick coating (up tp 3 mm). Cermet deposit by this method has shown high wear and corrosion resistance. The tungsten carbide (WC) content will be varied (0, 35, 50 65 wt%) to evaluate its morphology, chemical composition and corrosion behavior of the coating. Two techniques have been used to characterise the powders and coatings which are scanning electron microscopy (SEM) and x-ray diffraction (XRD). Micro-scale abrasion wear tester and dry sand rubber wheel has been used for wear behaviour evaluation. It is found that, for all coatings with WC, XRD spectrum shows two type of tungsten carbide which are WC and W2C, nickel (Ni) and nickel boride (Ni3B). By increasing the WC contents, the WC distributions are more homogeneous. Lower WC content shows the WC are tend to sinking to the bottom layer of the coating due to its high density compare to the nickel. The corrosion result shows that by increasing the carbide content, not much changes to the corrosion potential. The corrosion for cermet coating is due to removal of binder follow by carbide detachment. The corrosion in acidic electrolyte is higher compares to in alkaline electrolyte
Mechanical properties of AA7075 aluminium chip reinforced rice husk silica by solid state technique
No full textTypes of reinforcements in Metal Matrix Composite (MMC) are essential to form a better MMC due to the bonding element to the based matrix. This research was carried out based on the recycling of aluminium alloy AA7075 reinforced rice husk silica (natural waste fibres) as MMC. Solid state technique was used to examine the effect of rice husk silica as a reinforcement agent in MMCs. This technique remarkably lower operation costs and resources compared to conventional cast recycling. Recycled aluminium chip AA7075 with the addition of composition as-received untreated and treated rice husk silica (2.5, 5, 7.5, 10, and 12.5 wt%) were used. Treated rice husk was soaked in hydrochloric acid to fasten the burning process at temperatures of 700 and 1000°C. MMC samples were prepared using a cold compaction method by setting of load compaction of 9 tons for 20 minutes. Then, the MMC samples were sintered at a temperature of 552°C. Mechanical properties of MMC were obtained from hardness and compression tests, while optical microscope (OM) and scanning electron microscopy (SEM) were used for microstructural analysis of MMC samples. For mechanical properties, the hardness of MMC was higher at 10 wt% rice husk silica, i.e., 65.93 Hv for untreated, and 69.52 Hv for treated rice husk. These results were based on rice husk silica that burned at 700℃. It found that aluminium chip sample without reinforcement was 53.49 Hv, which is lower than samples at 10 wt% of rice husk silica. For the compressive strength, silica burned at 700℃ indicated rice husk silica at 5 wt% obtained high strength of MMC with 333.63 MPa for untreated, and 322.52 MPa for treated rice husk silica. In comparison, aluminium chip without a reinforcement sample was found to lower strength with 290.47 MPa. Based on this research, the reinforcement of rice husk silica burned at 700℃ has better properties of MMC compared to rice husk silica burned at 1000℃
A review on aviation restructuring action to survive in COVID-19 challenges: Malaysia perspective
No full textAviation is the most affected by the global outbreak of COVID-19, as traffic has almost ceased, causing airlines to be completely grounded, placing them in severe financial distress. The survival of airlines, indeed, the landscape of the domestic and global aviation industry at the end of the crisis, is still unfolding. As few months passed since the Movement Control Order (MCO commenced, Malaysia has successfully flattened the curve for infections in this country by conducting acute case detections and screen those who in high risk group such as Malaysians returning from overseas and so on. Malaysia has slowly reopened its economy sector to allow businesses resumed with strict Standard Operation Procedures (SOP) to be followed. Therefore, this chapter will review the action that airlines and airport management in Malaysia had revised its financial strategies to recover quickly from the losses over past few months
CFD simulation study of multistage vertical axis wind turbine (VAWT)
No full textNowadays, the generation of energy from wind power has grown significantly as one of the most important renewable energy sources in the world today. In this study, the performance of a multistage vertical axis wind turbine (VAWT) has been assessed through 3D computational fluid dynamics (CFD) simulation approach based on K-omega shear stress transport (SST) models using the ANSYS Software. The inexpensive, omnidirectional, compact and easy to assemble Savonius rotor has been applied in this study along with the multistage-rotor concept. Multistage-rotor is where one stage of the rotor is placed on top of another stage of the rotor. The wind speed tested ranges from 5 m/s to 11 m/s at a tip-speed ratio (TSR) ranging from 0.2 to 1.0. The findings for torque and power with different operating wind speed demonstrated that as the wind speed increases at constant tip-speed ratio (TSR), the torque also increases; meanwhile, the torque coefficient decreases. However, when the wind speed increases along with the increasing TSR, the power generated increases. Meanwhile, the performance power coefficient has a directly proportional relationship with the TSR and an inverse relation with the wind speed tested
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