Azmi Yahya

Effect of adding palm oil mill decanter cake slurry with regular turning operation on the composting process and quality of compost from oil palm empty fruit bunches.

Formation of compost from oil palm empty fruit bunches (EFB) and decanter cake slurry by adding palm oil mill effluent (POME) with regular turning operation was investigated. The experiment was conducted in a commercial composting plant under the normal production process. The addition of decanter cake slurry has hastened the composting process of the EFB. The C/N ratio after 51 days for the mature compost with the decanter cake slurry was 18.65 while that of the matured compost without the decanter cake slurry remained high at 28.96. The compost formed from the addition of decanter cake to EFB and POME had 46.4% nitrogen, 17.9% phosphorus, 17.7% potassium and 23.1% calcium more than that without decanter cake. The use of compost produced from EFB, POME and decanter cake slurry could solve more environmental problems and enhance economic benefits in the oil palm industry.

Performance and exhaust emissions of a compression ignition engine operating on ester fuels at increased injection pressure and advanced timing

Abstract Effects of increased injection pressure and advanced injection timing on the performance and exhaust emission characteristics of a direct injection, naturally aspirated John Deere 4239D engine operating on methyl soyoil ester (IV (iodine value) = 125−135) and methyl tallow ester (IV = 47−53) were studied. The test engine was fully instrumented to provide all the required measurements for determination of the needed performance and exhaust emission variables. Four treatment combinations consisting of two levels of injection pressure (18.6 MPa and 24.1 MPa) and two levels of injection timing (19° before top-dead-centre (BTDC) and 14° BTDC) were employed. The physical and chemical properties of the test fuels were earlier determined in accordance to the ASTM and AOCS standards. Results indicated that the engine operating on ester fuels at the manufacturers injection pressure-timing setting (18.6 MPa and 14° BTDC) had lower carbon monoxide and unburned hydrocarbon carbon emissions and smoke levels, despite a slight increase in brake specific fuel consumption, as compared with when it was operating on No. 2 diesel fuel (control fuel). There were no significant differences in the engine brake specific fuel consumption and brake thermal efficiency between the ester fuels. However, between the two ester fuels, the saturated ester fuel (methyl tallow ester) showed slightly lower carbon monoxide and unburned hydrocarbons emissions, and higher smoke levels. The engine performance and exhaust emission characteristics of the engine operating on the ester fuels at advanced injection timing were better than when operating at increased injection pressure. Poor fuel combustion near the maximum operating power level was indicated with the engine operating on ester fuels at increased injection pressure. Complete fuel combustion was suppressed during high fuel flow probably due to the lack of oxygen within the spray envelope. Thus, fuels in some locations within the spray envelope that were too rich to burn escaped as unburned hydrocarbons, or burned incompletely causing high carbon monoxide and smoke levels in the exhaust emissions. Operating the engine at such conditions for extended periods could give rise to deposits problems in the combustion chamber. The engine performance and exhaust emission characteristics between the two ester fuels were almost similar at advanced injection timing and increased injection pressure.

Design and Development of a Segmented Rubber Tracked Vehicle for Sepang Peat Terrain in Malaysia

In order to improve the crossing ability, the tractive performance of a vehicle operating on low bearing capacity peat terrain and the loss of income resulting from downtime and maintenance cost, the vehicle must be designed with an ability to adapt to the changes of prevailing operation conditions. This paper describes the design and development of a new segmented rubber tracked vehicle for peat terrain in Malaysia. A new mathematical model for peat terrain, which was used to determine the forces at the ground contact parts of the track element of front idler-terrain, intermediate roadwheels-terrain, and rear sprocket-terrain interfaces is developed. The simulated performance results, such as vehicle average motion resistance coefficient of 6.8–7.9%, drawbar pull coefficient of 25.22–47%, and the tractive efficiency of 74–77% for the vehicle slippage of 5–20% indicate that the vehicle can meet the peat terrain field requirement with its optimal power consumption.

Physical and chemical characterization of methyl soyoil and methyl tallow esters as CI engine fuels

Abstract Fourteen ASTM (American Society for Testing Materials) tests and four AOCS (American Oil Chemists Society) tests were employed to characterize the fuel properties of methyl soyoil ester and methyl ta;low ester. Soybean oil and animal tallow were considered in this study as the two are leading sources for alternative CI engine fuel. Comparisons and evaluations of the properties of the esters were made against the Phillips No. 2 control diesel fuel and the ASTM D975 requirement limits set for No. 2 diesel fuel. Results from this study indicated distinct differences in the chemical compositions and some of the physical properties between the ester fuels and No. 2 diesel fuel.

Integrated mechanics of hybrid electrical air-cushion tracked vehicle for swamp peat

This paper presents an integrated mechanics for the design of hybrid electrical air-cushion tracked vehicle. The air-cushion of HETAV is protected with a novel-design air-cushion supporting system which can adjust automatically. A propeller is installed on the vehicle to develop additional thrust for overcoming the dragging motion resistance of the air-cushion system. The mean values of traction for the vehicle with propeller compared with no propeller increased 10.21% and 6.47% for the vehicle weight of 2.45 kN and 3.43 kN, respectively. Similarly, it was found that the mean values of vehicle’s motion resistance decreases 12.63% and 25.81% for the vehicle weight of 2.45 kN and 3.43 kN, respectively.

Human energy expenditure in lowland rice cultivation in Malaysia

A study was undertaken to evaluate the human energy consumption of various field operations involved in lowland rice cultivation in Malaysia. Based on recorded average heart rates, fertilizing was found to be the most strenuous operation, with an average heart rate of 138 beats min(-1). There were no significant differences in the average heart rates of the subjects among the individual tasks within the first plowing, second plowing, and harvesting operations, with the average heart rates for these three tasks being 116, 106, and 106 beats min(-1), respectively. The corresponding energy expenditures were 3.90, 3.43, and 3.35 kcal min(-1). Loading the seed into the blower tank and broadcasting the seed were the most critical tasks for the seed broadcasting operation, with average heart rates of 124 and 136 beats min(-1), respectively. The highest energy expenditure of 418.38 kcal ha(-1) was observed for seed broadcasting, and the lowest energy expenditure of 127.96 kcal ha(-1) was for second plowing. The total seasonal human energy expenditure for rice cultivation was estimated to be 5810.71 kcal ha(-1), 55.7% of which was spent on pesticide spraying. Although the sample size in this study was relatively small, the results indicated that human energy expenditure per unit area (kcal ha(-1)) was positively linked to the average heart rate of the subjects and negatively linked to the field capacity. Thus, mechanization of certain tasks could decrease worker physical effort and fatigue and increase production.

Mobility Investigation of a Designed and Developed Segmented Rubber Track Vehicle on Sepang Peat Terrain in Malaysia

Abstract The traction mechanics of a vehicle was developed based on the track-terrain interaction mechanism. The vehicle was tested on three different terrains: terrain I, terrain II, and terrain III. The tractive effort of the vehicle increased 14 per cent when the moisture content of the terrain increased from 59.85 per cent to 81.06 per cent. A traction coefficient of 48 per cent of the vehicles gross weight justified the vehicles optimum design for the Sepang peat terrain. Less variability of the vehicles tractive effort for straight motion in the range of 7.5 per cent to 13.2 per cent and for turning motion in the range of 9 per cent to 11.5 per cent between the predicted and measured tractive effort on the peat terrain III for different loading and operating speeds substantiate the validity of the developed mathematical model.

Tractive performance of a designed and developed segmented rubber tracked vehicle on Sepang peat terrain during straight motion: theoretical analysis and experimental substantiation

The vehicle field tests were conducted on three different types of peat terrains: terrain type I, terrain type II and terrain type III with two loading conditions at travelled speeds of 6 km/h and 10 km/h. The different tractive efforts of the vehicle were found during field testing due to the hydrodynamic effect, different cohesiveness and the internal frictional angle. The significant difference of the vehicle slippages were found due to the variation of the moisture content of the terrain. The least variability between the measured data over the predicted data substantiates the validity of the mathematical model.

A NOVEL VARIABLE RATE PNEUMATIC FERTILIZER APPLICATOR

The canopy prevents the use of global positioning system based fertilizer applicators in oil palm plantations. Hence, a radio frequency identification triggered variable rate pneumatic fertilizer system was developed for this application. A real-time embedded system was used as the core controller, LabVIEW software was used to program and coordinate the operations of the embedded system and the host computer. A speed measuring unit was used to provide feedback to the system. A field test was conducted to examine the response time. The sensors were calibrated in the laboratory and the measurement linearity had regression coefficients close to 1. Two to three seconds were required for the device to respond to changes in application rate. It is expected that this approach will become an alternative in plantations where the canopy hinders proper application of global positioning systems.

Simulated steerability of a segmented rubber tracked vehicle during turning on sepang peat terrain in Malaysia

A simulation study on the steerability of a segmented rubber tracked vehicle on low-bearing-capacity peat terrain is performed by considering the position of the vehicles turning pole. A set of mathematical equations in the analytical model is used to predict all the important operating parameters of the vehicle during turning to establish the vehicles steerability. Seven road wheels are used on each side of the track in order to avoid the track deflection between two consecutive road wheels. A road wheel diameter of 0.22 m and road wheel spacing of 0.225 m are employed to keep the track on the terrain as a rigid footing. The simulation of vehicle steerability in this study is focused on considering the vehicles speed of 10 km/h. The turning pole coincides with the same level of the amount of eccentricity of nominal ground pressure and the resultant turning moment resistance.