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The aim of this research article is to develop a mathematical model of the impact cutting behaviour of a circular cutting blade on kenaf stems. The model predicts and validates the effects of crop maturity and varieties on the cutting torque, power, and energy required during kenaf harvesting. The developed mathematical model for predicting the cutting torque, power, and energy for an improved tractor mounted kenaf harvester was found to be accurate. The cutting torque, power, and energy consumed during kenaf harvesting increase steadily with increased maturity for all varieties of kenaf. Also, the highest cutting torque, power, and energy during the harvesting of Ifeken 400 ranged from 1.51 Nm to 3.36 Nm, 10.19 kW to 22.61 kW, and 1.77 Joules to 3.94 Joules. [ABSTRACT FROM AUTHOR]

The design, fabrication and evaluation of a tractor mounted kenaf harvester was carried out in this study. The machine comprises of a rotary drive mechanism, which was adapted from a forage harvester. A review of kenaf stem properties was done to ensure accuracy of the design calculation for the machine components. The design of the machine was carried out using standard design procedures. A kenaf experimental field was set up at the Obafemi Awolowo University Teaching and Research Farm for the evaluation of the machine. The machine was evaluated using, crop maturity, crop variety and forward speed of the machine as factors. Effective field capacity and field efficiency of the machine were used as performance output parameters. The data obtained was analysed using 3-level factorial response surface methodology (RSM) of design expert software. The effective field capacity was observed to decrease with increase in plant maturity and increase with increase in forward speed of the machine. The highest effective field capacity recorded was 2.13 ha/day with Ifeken 100 at crop maturity of 10 weeks after planting, and forward speed was 5 km/hr. The field efficiency of the machine was found to decrease with increasing crop maturity and forward speed of the machine. The highest field efficiency of 97% was recorded for Ifeken 100 when the crop maturity was 10 weeks after planting and at 2 km/hr forward speed of machine. [ABSTRACT FROM AUTHOR]

A cabinet dryer fabricated using locally available materials was evaluated in this study. The drier comprises a heating chamber, heat exchanger, drying trays, 3-phase blower, three heating elements of 1800 W each, and a control box consisting of temperature control, contactor, thermocouple, and circuit breaker. The dryer was evaluated based on power consumed, moisture removal, drying rate, and drying efficiency. The result showed that the energy consumed when drying plantain chips, moringa leaves, okra, and locust beans were 346.55, 55.92, 110.63, and 49.64 kJ, respectively. The energy consumed increased with an increase in the moisture removed and drying time. Similarly, the drying rate for plantain chips, moringa leaves, okra, and locust beans was 34.80, 5.40, 10.80, and 6.00 g h-1, respectively, which depended on the initial moisture content of the product and the air velocity. The drying efficiency ranged between 62.1% and 65.5%, and it reduced with an increase in the amount of moisture removed and the drying temperature. The drying system promises satisfactory performance for small-scale applications for the products with which the dryer was tested. [ABSTRACT FROM AUTHOR]

In order to design appropriate processing machineries, the knowledge of the force and deformation curve of agricultural materials is very important. In this research, fracture resistance of kola nut (cola nitida) was measured in terms of the rupture force, compressive stress, modulus of elasticity and energy absorbed. Kola nuts were quasi-statically loaded in horizontal and vertical orientations with moisture content at four levels (47.59%-61.41%) and loading rate of 5 mm min-1. The result showed that the compressive load decreased from 458.95 to 334.41 N and 605.46 to 228.10 N, compressive stress decreased from 0.40 to 0.289 MPa and 0.52 to 0.20 MPa and energy absorbed decreased from 3.46 to 1.81 J and 2.79 to 0.52 J, for vertical and horizontal orientations, respectively. These findings will be useful in the development of processing equipment for kola nuts [ABSTRACT FROM AUTHOR]

The performance evaluation of an existing kenaf decorticator was carried out in this study. A field was planted with kenaf. It was maintained and monitored until the kenaf was 10 weeks old when the evaluation of the machine commenced. The kenaf decorticator was evaluated using different operation parameters, which included plant ages (10, 11 and 12 weeks after planting), kenaf stem sizes (0.0001-0.005 m, 0.005-0.015 m and 0.015-0.023 m) and decorticator speeds (8, 9 and 10 m s-1) giving rise to a 3 by 3 factorial experiment. The result showed that the highest throughput value obtained was 612.26 kg h-1 when the machine was operated at 9 m s-1 using 0.015-0.023 m kenaf size harvested at 12 weeks after planting. The lowest percentage of kenaf fibre trapped in the machine was 10% which was obtained at week 12, when the machine operated at 9 m s-1 although ANOVA of fibre trapped showed that the operational parameters had no significant effect. The percentage waste collected decreased from 54% as the size range and speed reduced to 8 m s-1 while the percentage of fibre decorticated increased from 31% to 49% as the speed decreased to 8 m s-1. The kenaf extraction efficiency increased from 74% to 91% as the size range increased. ANOVA showed that only size range had a significant effect on the efficiency of the machine. Duncan's multiple range test showed that 0.015-0.023 m had the highest mean of efficiency but maturity of stem and speed was statistically insignificant. The study concluded that the optimal operational parameters of the machine were 8 m s-1 with 0.015-0.023 m kenaf size and 12 week of kenaf maturity. [ABSTRACT FROM AUTHOR]