The effect of some extrusion factors on soybean crud residue-based floating fish feed was investigated. Extrusion was conducted at 20%, 25%, and 30% moisture content level, die size of 2 mm, 4 mm and 6 mm, and screw speed of 150 rpm, 200 rpm, and 250 rpm. Pearson square method of fish feed formulation was used to attain a 35% protein content of catfish feed protein requirement. Optimized value of extrusion factors moisture content, die size, and screw speed were 30%, 6 mm, and 150 rpm respectively and the optimized result of responses, expansion rate (ER) floatation rate (FR) sinking velocity (SV) specific mechanical energy (SME) swelling capacity (SC) water absorption index (WAI) water solubility index (WSI) hydration capacity (HC) and hydration index (HI) are 32.73%, 95.87%, 0.024 m s-1, 16.97 kJ kg-1, 1.73, 1.61, 2.76, 0.51, and 0.67 respectively. Feed moisture content and die size have the most significant effect on the physical and functional properties of the extrudate. Coefficient of determination R2 ranges from 0.65 to 0.96, lack of fit not-significant, desirability in optimization of 0.806, suggesting adequacy of research. Soybean crud residue base floating fish feed has been formed and evaluated with an outcome of high efficacy. This extruded producing model can be used for both domestic and industrial scales of catfish feed production.

An extruding machine for the production of floating fish feed was designed and fabricated. Performance evaluation of the fabricated floating fish feed extruding machine was done. The design of the hopper; shaft, barrel, screw and die of the machine were done using standard equations. Effect of extrusion parameters which are moisture content (20% 25%, 30%, 35%, and 40%) die size (2 mm, 4 mm, 6 mm, 8 mm and 10 mm) and screw speed (150 rpm; 200 rpm, 250 rpm, 300 rpm and 350 rpm) on expansion ratio, floatability, specific mechanical energy and efficiency were evaluated. The result shows that moisture content has significant effect on all the variables, as highest expansion ratio of 32% was obtained at 30% moisture content and 6 mm die size. Highest feed floatability was 97% at 30% moisture content and 6 mm die size. The highest specific mechanical energy of the machine was 30 kJ/kg at 40% moisture content and 4 mm die size. Die size variation also shows high impact on the machine performance, showing highest efficiency of 83% at 10 mm die size and 250 rpm while the floatation rate was 98% at 6mm die size. Screw speed has significant effect on efficiency having the highest as 85% at 150 rpm and floatability of 93% at 150 rpm while the specific mechanical energy of 29 kJ/kg was the highest at 350 rpm. Operation condition was at its best at 30% moisture content; 6 mm die size and 150 rpm of screw speed. The feed moisture content, machine die size and screw speed have significant effect on the performance of the machine. Careful selection and combination of these factors will give optimum performance of the machine during extrusion of resin.

The objective of this paper is to present a review on hybrid solar dryer and its modification for further research.  Energy is not evenly distributed in the world, developed countries have more than enough while developing countries are facing it inadequacy. Rural areas where agricultural activities are taking place largely have no access to power supply to power drying equipment. Large amount of farm produce of about 30% were damaged due to lack of drying facilities. This has been resolved with the application of evolution of solar dryer and to a better level, use of hybrid solar dryer of exponential value over open air sun drying. It was found that the drying efficiency of hybrid solar dryer was 35%, while the maximum drying temperature was 80oC. Retention time in drying chamber was found to be between 2 – 3 days, it indicate the sustainability of hybrid solar dryer for drying high moisture farm produce. Various design of solar dryer and hybrid solar dryer were reported in the literature thus for is presented. Hybrid solar dryer could be developed further with the inclusion of dehumidifier as a system aiding drying.