Numerical investigation of error properties of Green\u27s Function Discretization

Error Property of a highly accurate method for discretization solutions of the Helmholtz equation, called the Green\u27s Function Discretization (GFD) is studied. Numerical results indicate that 6th order of accuracy is obtained using this method in interpolating any acoustic source. Various combinations of interpolating functions are examined, and are shown to maintain the order of accuracy. The accuracy of the discretization for skewed lattice stencils is also examined by numerical example and yields satisfactory results. Preliminary study on a 3-D problem using this method shown the same order of accuracy

Semiactive control policies : ride analysis for passenger vehicles

Comprehensive comparison on quarter-car, half-car and full-car models were conducted to analyze the effect of using semiactive control policies, namely skyhook, groundhook and hybrid controls, in improving ride quality of passenger vehicle. Sprung mass acceleration, suspension deflection and tire deflection responses were analyzed for measurements of ride quality, rattle-space and road holding. Three different analyses were conducted on each model; frequency-domain transfer function analysis, time-domain transient state and steady state analysis. Results shows that hybrid control policy gives significant improvements in most responses while at the same time it does not compromise road holding ability of vehicle. Further quantitative comparison of responses on all three models shows that quarter-car model is unable to accurately represent responses in full-car model. Half-car model gives reasonable representation of full-car model in some states. RMS analysis conducted on a H-car 2-DOF system shows good agreement to the previous work on Q-car 2-DOF. This book should benefit researchers working in the area of semiactive control of vehicle suspension system

Performance evaluation of PV module using water filters and infrared reflective glass covers

The Photovoltaic (PV) system converts only a selected band (0.35μm to 0.82 μm) of solar radiation to electricity. The absorption of radiation outside this band leads to a temperature raise of PV module which affects its performance. Experiments were performed to prevent radiation outside the selected to reach the PV panel using water filtersand different types of infrared reflective pigments. The results of the experiments showed that the optimum water filter panel was the one with thickness of 10 mm. It led to about 4% improvement in the open circuit voltage of the module, and a significant reduction in the module’s average operating temperature up to 21oC. The optimum coated cover glass was 10 micron IRR glass cover which led to about 50% reduction in solar radiation, 22o In 1994, Beauchamp [6] used blue-red reflecting cover glasses to reduce the absorptance of infrared radiation in GaAs and amorphous solar cells. He found out that three percent of output power increased due to lowering the temperature of solar cells by using blue-red coated cover glasses. Sopian et al. [7] improved the thermal and the electrical efficiency of the thermal photovoltaic system by designing and testing a double pass air PV/T collector.Tripanagnostopoulos et al.[8] added thin flat metallic sheet (TFMS) in the middle of the air channel in the PV/T-air collector but its effect on the operating temperature of the photovoltaic cells was not significant.Russell et al.[9] conducted experiments on triple junction solar cell using Ultra violet reflective (UVR) and infrared reflective (IRR) coatings on glasses in order to reflect the ultraviolet and infrared radiation C reduction in the average temperature of the module, and 5.3% improvement in its open circuit voltage

IoT-based electromagnetic actuator for CVT: basic design and prototyping

Resulting from the slow fluid pressure responses and fluid viscosity loss, the present hydraulic-powered CVTs produce jerky movements, rattling noise and unequal power transmission at uphill climbing. The aim of this article is to present a design and prototyping of an electromagnetic actuated continuously variable transmission (EMA-CVT). Using the kinematics analysis of CVT clamping forces and electromagnetic forces, the EMA-CVT is modelled. An internet of things (IoT) has been developed to control the EMA-CVT gear ration with integrating a fuzzy logic controller CVT, wheel speed sensor, CVT pulley position sensor, and CVT secondary pulley revolution sensor. The fuzzy logic controller is used to control the current supply to the EMA. The CVT has a failsafe mode that allows to manually adjust the gear ratio if any of the sensor of the IoT system malfunctions. The EMA develops the electromagnetic force in the range of 185–266 N for the supply current in the range of 3–3.7 amps

An air conditioning system providing cooling, water heating and drying

In the tropics, air conditioning is essential as the operating daily ambient temperature is high. In Malaysia and Singapore, most of the houses and apartments are air conditioned, at least one room. Every kW of electricity consumed by the air conditioner, about 4 kW is thrown into the atmosphere. Energy is available at the inlet to the condenser at about 85oC and can be utilized for useful purposes. Here, waste heat from air conditioners is utilized for water heating and drying purposes. A water condenser fitted at the exit of compressor absorbs most of the superheat and latent heat. Even a 60% recovery of this waste energy can heat 200 litres of water to 60oC within about three hours. A dryer connected at the exit of air condenser is fitted with filter to supply clean hot air to the dryer. The system reduces global warming and the payback period is less than two years

Simulation study for economic analysis of biogas production from agricultural biomass

A process of anaerobic digestion of agricultural biomass was simulated by SuperPro Designer software v 8.5 to analyze the costof production. The simulated project used fruits and vegetable wastes as a feedstock. The concentration of methane produced is55 % (v/v) from a total of 936.8 m3 . h–1 biogas and after purification, the concentration of methane is upgraded up to 95 % (v/v).The system was designed to treat the agricultural waste, and was able to reduce more than 60 % of the initial COD (chemicaloxygen demand). From the study, economic analysis shows that the profit margin is achieved at 11 % and the rate of return ofinvestment is at 12 % which gives a payback period of 8.2 years

Analysis of engine performance with NGV

This paper presents experimental results carried out to evaluate brake thermal efficiency and fuel consumption by gasoline and compressed natural gas (CNG). In this experiment a 4-cylinders gasoline engine has been modified to bi-fuel engine, then the engine is operated for the condition of fixed load condition to obtain same brake power output from both fuels and all the corresponding results such as fuel flow rate and brake thermal efficiency have been measured for evaluation. The test results show that gasoline has higher fuel consumption and brake thermal efficiency than CNG. Details results including fuel consumption and brake thermal efficiency have been discussed in this paper