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Due to increasing demand for food, industrial applications and biodiesel production on vegetable oils, optimization of oil extraction processes has become imperative to obtain maximum oil yield from vegetable oil feedstocks. The effect of process factors: moisture content, roasting temperature, and time, extraction temperature, and time on oil yield from sandbox seed by solvent extraction were investigated using a 5 × 5 Central Composite Rotatable (Experimental) Design of Response Surface Methodology. Results obtained were analyzed using Analysis of Variance (ANOVA) and SPSS statistical tool at (p = 0.05). The optimum conditions predicted were validated by experiments. The American Oil Chemists’ Society AOCS 5-04 standard procedure for solvent extraction was used in the experiment. The oil yield from the sandbox seed ranged from 20.9-53.6%, and was increased at the range (6-10%) moisture content, (80-100°C) roasting temperature, (5-15 min) roasting time, (90-100°C) extraction temperature and (90-150 min) extraction time. The optimum oil yield of 53.6% was obtained at the processing conditions of 10.0% moisture content, 95oC roasting temperature, 15 min roasting time, 65oC extraction temperature, and 90 min extraction time. Mathematical models to predict sandbox seed oil yield at varying process conditions were developed with an R2 (0.81). The optimum extractable oil yield of 57.10% was predicted for sandbox seed at processing conditions of 10.25% moisture content, 98.72oC roasting temperature, 17.63 min roasting time, 67.01oC extraction temperature, and 96.6 min extraction time. The study results provide data for equipment and process designs for oil extraction from the sandbox and other oilseeds.

The finitude and environmental impact of petroleum fuels have led to the search of alternative fuels and biodiesel has proven to be an alternative fuel to petro-diesel with less environmental impact. Engine performance and exhaust emissions of Sandbox Methyl Ester (SBME) fuel were evaluated. Pure SBME (B100) was blended with diesel at 5, 10, 15, 20, 25 and 50% volume designated B5, B10, B15, B20, B25 and B50 respectively. The diesel was used as a reference fuel. The fuel blends (B100-B5) and diesel was used to power a 4-stroke-single-cylinder diesel engine coupled to a dynamometer and a 7.5 kW alternator with varying loads. The brake specific fuel consumption (bsfc), brake power, thermal efficiency, carbon monoxide (CO), oxides of nitrogen (NOx) and hydrocarbon emissions were evaluated.  The results of no-load to full-load indicated that diesel utilized the lowest bsfc of 0.14-0.62 kg/kW.h to produce the highest brake power of 5.6-3.7 kW. Similarly, the range of B5-B25 utilized bsfc of 0.16-0.86 kg/kW.h to produce the brake power of 5.1-2.9 kW. The brake thermal efficiency was 58-14% for diesel, and 52-10% for B5-B25. CO emission was reduced to 38.24-11.11% for B5 and 64.71-55.56% for B100. HC emission was reduced to 9.09-5.56% for B5 and 45.45-30.56% for B100. NOx emission increased with SBME concentration. The results obtained for the SBME engine performance and exhaust emissions established it as a potential fuel to power internal combustion engines.

Optimization of process variables has become very vital in oil extraction processes to obtain maximum oil yield from oilseeds and nuts. This work focussed on the optimization of process oil extraction process from sandbox seed by mechanical expression. Effects of moisture content, roasting temperature, roasting time, expression pressure and expression time on oil yield from sandbox seed was studied using a 5×5 Central Composite Rotatable Design of Response Surface Methodology experimental design. Results obtained were subjected to Analysis of Variance (ANOVA) and SPSS statistical tool at (p = 0.05). Optimum conditions predicted were validated by experiments. All the processing factors were significant at (p = 0.05) for the sandbox oil yield except roasting temperature. The experimental results and predicted values showed low deviation (0.01-0.62). Oil yields obtained from the sandbox seed at varying process conditions varied from 16.38-38.68%. The maximum oil yield of 38.68% was obtained when the sandbox seed was subjected to process conditions of 6% moisture content, 85°C roasting temperature, 15 min roasting time, expression pressure of 20 MPa and 8 min pressing time. Mathematical equations to predict sandbox seed oil yield at varying process conditions were developed with an R2 (0.8908). The optimum extractable oil yield of 38.95% was predicted for sandbox seed at processing conditions of 7.03% moisture content, 97.72°C roasting temperature, 11.32 min roasting time, 15.11 MPa expression pressure and 8.57 min expression time. The study results provide data for designs of process and equipment for oil extraction from sandbox and other oilseeds.

The properties of kernels, grains and seeds are important in the development of equipment for transportation, handling and processing. Physical and mechanical properties of Gmelina arborea where experimentally determined. The moisture content of Gmelina arborea was determined as 41.30%wb. The major, minor and intermediate diameters were 18.16 ± 1.79 mm, 10.52 ± 0.93 mm and 9.40 ± 0.81 mm respectively. The geometric and arithmetic mean diameter were calculated as 12.12 ± 1.10 and 9.56 ± 0.90 mm respectively. The sphericity was 66.91%, aspect ratio, 58.19, bulk and true densities, 0.64 kg/m3 and 0.96 kg/m3 respectively. The porosity and mass of a 1000 seeds were 66.67% and 621.33g respectively. The coefficient of friction determined on four different surfaces were; on wood, 0.4 ± 0.7, on galvanized steel, 0.37 ± 0.6, on glass, 0.36 ± 0.4 and on aluminum, 0.34 ± 0.6. The angle of repose was 24.09o. The compressive test conducted on the three major axes; vertical, horizontal and transverse shows that the energy needed for cracking of the Gmelina arborea is least on the horizontal axis, 0.808 ± 0.19 kN, followed by the vertical axis, 1.496 ± 0.35 kN and then the transverse axis, 2.39 ± 0.20 kN, with corresponding stress as 1.52 ± 0.35, 2.90 ± 0.45 and 4.90 ± 0.44 MPa respectively.