No abstract

Appropriate technology for the conversion of solar radiation to thermal energy is vital for food dehydration. Solar drying considered an advancement of sundrying is an efficient solar energy system. A reliable and low-cost multi-crop solar drying technique is required for small scale farmers in Sri Lanka. Therefore, the objective of this study was to develop a solar heater assisted multi-crop dryer for small scale farmers. The main components of solar dryer are flat plate solar collector, drying chamber, solar panel with air DC heater, turbo ventilator, exhaust fans, and temperature control system. The performance of the fabricated solar assisted multi-crop dryer with DC air heater was evaluated for drying rate and drying efficiency of three agro-products; bitter gourd (Momordica charantia), jackfruit (Artocarpus heterophyllus) and mushroom (Pleurotus ostreatus). The drying rates were 0.151 kgh -1 for bitter gourd, 0.145 kgh -1 for jackfruit, and 0.154 kgh -1 for mushroom. The efficiency of solar collector was 25.84%. The drying efficiencies for bitter gourd, jackfruit, and mushroom were 12.85%, 12.35%, and 13.15%, respectively. Further, favorable colour could be achieved by the modified solar assisted multi crop dryer. Therefore, the solar assisted multi-crop dryer designed in the present experiment is an effective method of converting solar radiation to thermal energy and could be recommended for small scale farmers in Sri Lanka for drying agro products.Further improvements are required to increase solar thermal efficiency.

Abstract:Particle size affects many characteristics in the manufacturing process. Controlling the particle size helps to assure that the milled material will be consistent and repeatable with respect to firstly color, that is, uniform particles assure batch-to-batch color consistency, Secondly, flowability that is critical to packaging, tableting, weighing. Thirdly, uniformity, that is , consistent bulk density.Fourthly, density -helps control shipping costs and minimize dust. Fifthly, reconstitution, that assures the desired dissolution rate, Sixthly, chemical reaction that is vital for uniform, controlled chemical change. Finally, taste that allows precise portion control for consistent taste. The aim of this project is to design and develop a rasp bar mill for size reduction of maize seeds for different purposes. The fabricated rasp bar mill is capable of feeding maize around 60-180 kg/h, delivering of grits 60-90%, with sieve effectiveness 90-100% at a power requirement of 800-1400W,for different sieve perforation sizes of 5, 6, 7, 8 mm respectively. Key words:Size reduction, Rasp bar mill, Maize gritting IntroductionMaize ( Particle size affects many characteristics in the manufacturing process. Controlling the particle size helps to assure that the milled material will be consistent and repeatable with respect to firstly color, that is, uniform particles assure batch-to-batch color consistency, Secondly, flowability that is critical to packaging, tableting, weighing. Thirdly, uniformity, that is , consistent bulk density.