Mechanical Engineering

This research has investigated the fluid characteristic effect in the engine cylinder of four-stroke direct injection diesel engine converted to port injection dedicated compressed natural gas (CNG) engine spark ignition. This research has using computational engine model for steady-state and transient simulation. The investigation and simulation of the engine cylinder flow performance characteristic profile based on engine computational model. The engine computational model has developed based from the diesel engine converted to port injection dedicated compressed natural gas (CNG) engine spark ignition. The simulation of engine model has simulated in variations engine speeds. The simulation results of fluid characteristics are shown the characteristics of in cylinder volumetric efficiency profile, percent burned mass, fuel/air ratio, fuel flow profile, total fuel consumption and total fuel energy entering to cylinder in variations engine speeds.

Compressed natural gas (CNG) is the most favorite for fossil fuel substitution. There are four methods to inject the CNG into the engine cylinder, such as gas mixer / carburetor injection, single point injection, sequential injection and direct injection. In sequential port injection CNG engines, gas fuel is injected by fuel nozzle injector via intake port into combustion chamber. To improve the perfect of mixing process of CNG fuel and air in combustion chamber is by arranging of injector nozzle holes number. The objectives this paper is to design and investigate the injector nozzle multi holes and the effect on airfuel mixing in combustion chamber of sequential port injection CNG engine based on variation intake valve lift using CosmosFlow simulation. The simulation of injected gas fuel and intake air mixing in the combustion camber of new injector nozzle multi holes geometries effect is conducted in 1.78mm, 3.55mm, 5.33mm and 7.10 mm intake valve lift and in 1000 rpm engine speed. The results are shown, that the 4 holes injector nozzle is has the best in air-fuel mixing. In the best trend air-fuel mixing results, the injected gas fuel and intake air has been mixed spread evenly in combustion chamber.

Natural gas in the form of compressed natural gas (CNG) becoming the subject of interest today, as the combustion of gasoline and diesel fuels result in the emission of noxious pollutants which threaten the very survival of life in this planet. this overview will concentrate on Malaysian scenarios of using CNG, and the trend of research to overcome the lack of CNG engine performance. The crude oil of fossil fuel is believed to be finished at the early decades of this century. According to this situation the use of compressed natural gas (CNG) become a very good option as the alternative fuel. However, the current situation shows that CNG still cannot replace the gasoline as a prime resource of fuel but it is expected that as the gas distribution network expands and the number of refueling stations increase, increasingly more dedicated single-fuel engines will be develop for mass production which will be designed from scratch and will be fully optimized to accommodate the characteristics physical and chemical properties of natural gas. Although at present bi-fuel gasoline conversions seem to be a convenient way to spread the use of CNG in the passenger car market, research of improving the performance of CNG-Engine vehicle at least nearly equal to the petrol engine. Most of the research done by automotive manufacturers, universities or research organizations is focusing on how to increase the performance of the vehicle by increase the engine power equal to gasoline vehicle counterpart, increase the driving range, reducing the weight of CNG storage, exhaust emissions meet or better than CARB/ULEV or SULEV standard, and meet all motor vehicle standard and trunk storage space comparable to gasoline vehicle.

Pelbagai jenis rawatan bekam disediakan:
1. Bekam Standard Points (Optimize Aliran Darah & Detoksifikasi).
Bekam jenis ini sesuai untuk semua lapisan umur bagi mencapai kesihatan optimum.
2. Bekam Kolesterol Tinggi / Darah Tinggi.
3. Bekam Sakit Urat, Kejang & Kebas.
4. Bekam Sakit Pinggang.
5. Bekam Diabetes.
6. Bekam Sakit Kepala Teruk / Migraine.
7. Bekam Gout (Asam Urat).
8. Dan Lain-Lain.

Rasulullah saw pernah bersabda bahawa:
“Sesungguhnya rawatan yang paling bagus untuk kalian gunakan ialah bekam”.
- HR Bukhari –

Bagi anda yang ingin mendapatkan rawatan bekam atau maklumat lanjut, anda boleh WhatsApp/Call/SMS ke :

017 - 4256 121

Atau klik link WhatsApp di bawah ini.
https://wa.me/60174256121

Pelbagai jenis rawatan bekam disediakan:
1. Bekam Standard Points (Optimize Aliran Darah & Detoksifikasi).
Bekam jenis ini sesuai untuk semua lapisan umur bagi mencapai kesihatan optimum.
2. Bekam Kolesterol Tinggi / Darah Tinggi.
3. Bekam Sakit Urat, Kejang & Kebas.
4. Bekam Sakit Pinggang.
5. Bekam Diabetes.
6. Bekam Sakit Kepala Teruk / Migraine.
7. Bekam Gout (Asam Urat).
8. Dan Lain-Lain.

Rasulullah saw pernah bersabda bahawa:
“Sesungguhnya rawatan yang paling bagus untuk kalian gunakan ialah bekam”.
- HR Bukhari –

Bagi anda yang ingin mendapatkan rawatan bekam atau maklumat lanjut, anda boleh WhatsApp/Call/SMS ke :

017 - 4256 121

Atau klik link WhatsApp di bawah ini.
https://wa.me/60174256121

Viscosity is the most important property of a lubricant that can affect bearing performance. It controls the film thickness that is established during an operation. In this study, the ultrasonic method was used to measure the static viscosity profile around a journal bearing by using shear reflection coefficients at several locations around the journal bearing. This enables the viscosity profile to be established. The technique introduced was found to be successful and acceptable results were obtained from certain regions of the journal bearing flow. This study serves as a preliminary work for developing viscosity measurement in a rotating journal bearing.

This paper presents an experimental investigation carried out to compare specific wear rate and surface morphology between Kenaf Epoxy Composite (KEC) and Carbon Fiber Reinforced Plastic (CFRP). Wear tests were carried out using Abrasion Resistance Tester (TR-600) in dry sliding conditions. These tests were performed at room temperature with different applied loads (5, 20 and 30N) and sliding velocity of 1.4m/s. Surface morphology of both materials was also examined before and after each test using an optical 3D surface measurement device. From the wear test, it was observed that the wear characteristics of KEC are comparative to those of CFRP. It was also found that the morphology of worn material composites in both cases exhibits a similar trend. This is a preliminary test for a future work on the enhancement of Kenaf Composites and the application.

The ability of nanofluids, an engineered fluid, to effectively remove heat has been proven to exceed that of a conventional fluid. However, dynamic viscosity may put a limitation on this ability. This paper presents the results of the experimental measurement of the dynamic viscosity for water-based nanofluids and the development of empirical viscosity models using the response surface method (RSM). The nanofluids that are being considered in this work are silicon dioxide (SiO2)-water and aluminum oxide (Al2O3)-water at a concentration of 0.01, 0.055 and 0.1 vol.%. Experiments were designed and analyzed according to the face-centered central composite design (CCD) in the RSM. ANOVA was used to evaluate the significance of the independent factors, which are the nanoparticle concentration and temperature. Empirical models to predict the dynamic viscosity of both nanofluids at a specific temperature and volume concentration were developed and validated. Excellent fits of the models were demonstrated by their high coefficient of determination, R 2. Results indicate that dynamic viscosity increases with nanoparticle concentration and decreases with temperature. It is also observed that the addition of less or equal than 0.1 vol.% of SiO2 in water would not significantly change the viscosity.

Estimation of the operational topology of the power grid is necessary for optimal market settlement and reliable dynamic operation of the grid. This paper presents a novel framework for topology estimation for general power grids (loopy or radial) using time-series measurements of nodal voltage phase angles that arise from the swing dynamics. Our learning framework utilizes multivariate Wiener filtering to unravel the interaction between fluctuations in voltage angles at different nodes and identifies operational edges by considering the phase response of the elements of the multivariate Wiener filter. The performance of our learning framework is demonstrated through simulations on standard IEEE test cases.

The objective of this paper is to determine the most technically feasible passive method in reducing the car interior temperature. Three methods were experimentally studied; using sunshades, ventilators and window tints. A 1.5 national sedan car was used in this study where it was exposed to direct sunlight for a period of 5 hours for four different cases. The temperatures measured by thermocouples strategically located within the car were obtained and analyzed. It is observed that the maximum temperature occurred at the dashboard for all cases. The usage of ventilators is found to reduce the average maximum temperature for the ambient air inside the car by as much as 3.3 o C. Although their performance is more or less similar with that for the window tints, their application is impractical. All in all, it can be concluded that the window tints is the best method in reducing the interior temperature.

This paper presents the numerical study on the usage of Al2O3 nanofluid-filled heat pipes in controlling the temperature of lithium-ion batteries, specifically for the application in powering the electric vehicle (EV). The heat pipes thermal management system (HPTMS) was modelled as a solid continuum body with high equivalent thermal conductivity. Thermal resistance network model was used to determine the equivalent thermal conductivity. The effect of heat inputs and the nanoparticle volume concentration on the performance of the HPTMS were studied. The simulation results were validated against previous experimental works and showed good agreement with each other. Results also indicate that by using 1.5%vol Al2O3 as the working fluid in the heat pipes, the battery surface temperature and the total thermal resistance can be reduced by as much as 4.44°C (7.28%) and 15%, respectively.

This study aims to optimize operating parameters of copper-sintered-wick heat pipes used in thermal management of lithium-ion batteries in EV application. The optimization was accomplished by using D-optimal design in the Response Surface Method (RSM). There are three independent variables or factors considered in this study; battery heat generation rate, the condenser length of the heat pipes and the coolant water flow rate. ANOVA analysis was used to evaluate the effect of each factor and the significance of the interactions. Developed regression models for both the maximum surface temperature, Tmax and the temperature difference, T were significant (p<0.0001) with excellent adjusted coefficient of determination, R 2 of 0.9945 and 0.9981 respectively. The results were optimized with the goals of maintaining the battery surface temperature and the temperature difference within the battery below the desired limit at the maximum heat generation rate possible. It was found that the optimum conditions occurred when the heat generation rate is 20.834 W, the condenser length is 150 mm and the water flow rate is 0.90 LPM. The predicted Tmax and T at these optimized conditions were verified by a numerical simulation and the difference between the predicted and the simulated values were within the acceptable error range of 3.64% and 13.12% respectively

and the operating temperatures on the rate of nanofluids heat transfer in a compact heat exchanger. 40 nm CuO nanoparticles was mixed with demineralized water at 2% and 6% volume concentrations. Sodium Lauryl Sulphate (SLS) powder was added to enhance the mixing process and stabilize the dispersion of the nanofluids. A custom-made closed loop test rig were designed, fabricated and tested for these experiments. The test rig was set-up to represent the actual ap-plication of the nanofluids in cooling of a compact heat exchanger. Experimental runs were conducted at varying operating temperatures which include the runs for water, CuO-water at 40 o C, 50 o C and 60 o C. The results indicate that by adding small amount of CuO nanoparticles into water as the base fluid, the rate of heat transfer and convection heat transfer coefficient would increases by at least 17.3% and 40% respectively. It was also discovered that CuO nanofluids with 2% volume loading produces greater increase in rate ...

Nanocomposite has been one of recent study interest among researcher, scientists, and students. With public consciousness about environment, there is a change in using environmental friendly's materials. With the incorporation of nanotechnology, the strength of the composite shouldn't be sacrificed because of the use of natural fibre. Kenaf has been studied extensively and has been one of the candidates to be used in composite and with hybridizing with glass fibre, The strength of the composite could be retained to be used widely. In this study, nanosilica was impregnated in hybrid kenaf and glass epoxy composite to and was tested for its longitudinal and transverse tensile properties. From this study, incorporation of nanosilica in hybrid kenaf and glass epoxy composite help to increase its tensile modulus up to 34.52%, and longitudinal tensile strength up to 13.64%.

Thermal control has become a critical factor in the design of enclosure for electronic equipment because of the recent trends in the electronic industry towards increased miniaturization of components and device heat dissipation. A great demand on the system performance and reliability also intensifies the needs for a better thermal management, especially with a product that is meant to be located near direct sun ray. The main objectives for this study are to plan a suitable mechanical design for an enclosed box and design a heat transfer mechanism suitable for the system to relief hardware accumulated heat to apply to an early drowsiness detection system. This paper reviews an enclosure design to efficiently dissipate heat produced from the electronics component inside an early drowsiness detection system. ____________________________________________________________________________________________