Desa Ahmad

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 Mechanical Properties of Kenaf Seed

This study was conducted to investigate some moisture-dependent physical and mechanical properties of kenaf seed (Hibiscus cannabinus L.). Selected physical and mechanical properties often are required for designing the planting, storage, and other processing equipment. The average length, width, thickness, geometric and arithmetic mean diameter of kenaf seed were 4.92, 4.70, 2.76, 3.98, and 3.81 mm. The average of the surface area, projected area, thousand seed mass and volume of kenaf seed increased from 46.9 to 53.7 mm2, 9.9 to 11.3 mm2, 26 to 30 g, and 19.4 to 25 mm3, respectively, with increasing moisture content from 6.8% to 25.2% d.b. Studies showed that as moisture content increased, the true density and bulk density decreased from 1341.4 to 1202.8 kg m-3 and 662.3 to 589.3 kg m-3, respectively. Also, in the same moisture range, the static coefficient of friction, filling and emptying angle of repose of kenaf seed increased linearly against the various surfaces, namely, stainless steel, aluminum and glass.

Investigations on a Novel Inductive Concept Frequency Technique for the Grading of Oil Palm Fresh Fruit Bunches

From the Malaysian harvesters perspective, the determination of the ripeness of the oil palm (FFB) is a critical factor to maximize palm oil production. A preliminary study of a novel oil palm fruit sensor to detect the maturity of oil palm fruit bunches is presented. To optimize the functionality of the sensor, the frequency characteristics of air coils of various diameters are investigated to determine their inductance and resonant characteristics. Sixteen samples from two categories, namely ripe oil palm fruitlets and unripe oil palm fruitlets, are tested from 100 Hz up to 100 MHz frequency. The results showed the inductance and resonant characteristics of the air coil sensors display significant changes among the samples of each category. The investigations on the frequency characteristics of the sensor air coils are studied to observe the effect of variations in the coil diameter. The effect of coil diameter yields a significant 0.02643 MHz difference between unripe samples to air and 0.01084 MHz for ripe samples to air. The designed sensor exhibits significant potential in determining the maturity of oil palm fruits.

Design and development of an Integrated Slasher (Pulverizer) for Sweet Potato Harvester: A Review

In this study information on the development of combined sweet potato harvester is presented. The study focuses on the design, manufacture and choice of the best slasher for cutting and fragmentation of stems and leaves (vegetative portion) for the crop to facilitate the process of harvesting and extraction of tubers. A survey on various types and forms of cutters (mowers) and knives normally used for cutting vines and leaves was conducted and concluded that the vertical type and flail type mowers are the most effective in removing of the vegetative growth. In addition there is a need to design an integrated harvester, which combines both the cutting and digging in a single pass in order to reduce the time taken for harvesting, the fuel consumption and the number of machines used since this will give some economical advantages. In addition to the design requirements, it is recommended that number of tests should be conducted to select the suitable speed for the tractor, the velocity for cutters and the length of knives for both sides of the ridges to avoid damage to the tubers.

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.

Development of a tractor-pulled motion resistance test rig for traction studies on towed narrow wheels

This work presents the development of a test rig (tractor pulled) for measurement of motion resistance of towed narrow wheels with a view to obtaining new design information to enhance the use of narrow wheels as traction members for low cost agricultural machines affordable by the low income earners or rural populace whose occupation is predominantly farming. The narrow wheels that can be used on the developed test rig are pneumatic bicycle wheels of different sizes, rigid bicycle wheel, motorcycle wheel and lugged-rigid wheel for a planting machine. The towing force which is equal to the motion resistance will be measured by the Mecmesin Basic Force Gauge (BFG) with a maximum capacity of 2.5 kN installed on the test rig. The gauge is connected to a notebook with a Dataplot program to record the towing force and import the measured force per unit time to the spread sheet for further analyses. The test rig comprises two parts, one part holding the wheel and the second part hitched to the tractor, in between the two is the BFG to measure the towing force and it is RS-232 interfaced to notebook PC. The test rig is designed for field use on different terrains to make comparison and obtain enough data to assist in the design and development of narrow wheel agricultural machinery. The effect of the different wheel sizes, axle loads and inflation pressures on the motion resistance of the test wheels can be investigated easily using the developed test

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.

Effects of Knife Shapes and Cutting Speeds of a Mower on the Power Consumption for Pulverizing Sweet Potato Vine

Two different shapes of knives (L and Y-shaped) for the rotary slasher with 300 knife cutting angle at three cutting speeds (1830, 2066 and 2044 rpm) were used to indicate their effects on the power consumption for pulverizing sweet potato vine which passed through the sieve (< 28 mm2). The results indicated that all the treatments were significant at p 0.01 significance level for the power consumption on sweet potato vine pulverizing. The best result was recorded from L-shaped knife with a power consumption of 52.12 Watts for sweet potato vine pulverization. Meanwhile, the best result was for the mower speed at 1830 rpm with the lowest power consumption of 61.23 Watts. The best performance for interaction between knife shapes and the cutting speeds was achieved by the L-shaped knife at 1830 rpm with lowest power consumption of 50.23 Watts at p 0.01.

Pulverization of sweet potato vine at different mower speeds

The effects of different mower speeds (2358, 2440 and 2553 rpm) and different knife angles (30?, 40? and 50?) on sweet potato vine pulverization were studied. The results indicated that all the treatments were significant at p < 0.05 and p < 0.01 significance level for the pulverized percentage of sweet potato vine. The 30? knife angle gave the best result with highest vine pulverized percentage of 54.60 %, and a mower speed of 2553 rpm had the finest vine pulverized percentage of 46.99 %. The best performance for interaction effect between knife angle and speed of mower was achieved by the 30? knife angle and a mower speed of 2440 rpm resulting in an average percentage of 61.27% of pulverized vine.

Effects of root zone cooling on butterhead lettuce grown in tropical conditions in a coir-perlite mixture

Growing temperate vegetable crops such as lettuce in the humid tropical climate of lowland Malaysia commonly results in heat-induced crop damage, delayed heading, and precocious bolting. Manipulating the root zone to a cooler temperature may alleviate plant damage caused by high ambient temperatures to a large extent. In this study, the effects of root zone cooling (RZC) on the growth and development of butterhead lettuce were studied in a containerized planting system containing a 3:1 coir-perlite mixture. Polyvinyl chloride (PVC) pipes were used to circulate cold water and cool the root zone of the experimental plants, while their shoots were exposed to the hot ambient temperature. The temperature of the root zone was measured at different depths (50 mm, 100 mm, 150 mm, and 200 mm from the surface of the media). The butterhead lettuce canopy diameter and number of leaves were significantly higher in the RZC treatment at the end of the growth stage compared to the control plants, and the yield, as measured by the shoot and root dry weight, as well as the root/total biomass ratio were also improved. The cooling pipes placed 100 mm below the surface provided a better growth condition for butterhead lettuce; at 100 mm, the RZC media had a mean daily temperature of 19°C and a minimum temperature of 14.4°C at 18:00. This study demonstrated the importance of optimizing root temperature for butterhead lettuce in an ambient hot tropical climate.