Properties of Grain Corn During Short Term Storage in Tropical Ambient Temperature

Grain corn in nature possesses a tendency to absorb and release moisture even during storage. Grain respiration will lead to fungal growth, consequently mycotoxin development and decreased nutritional components. Storage in tropical weather like Malaysia, in which the temperature is constantly hot throughout the year (temperature 23–33°C, with relative humidity around 81%) will promote further spoilage to the stored grain corn. Therefore, this paper discussed the properties of grain corn during three months of storage in a Malaysian weather setting. Grain corn with the initial moisture content of 12.5± 0.02% MC bagged in the; a) woven polypropylene jumbo bags, b) woven propylene 40 kg bag and c) plastic sealed container was stored in two different storage facilities located in MARDI for three months. The grain corn after three months of storage showed a consistent water activity, a darkening value in Chroma index, within the permissible limit of fungal growth and exhibits insect pest development of two major species of Coleoptera family. Grain corn is considered safe after three months of storage because low aflatoxin levels have been found, but the physical structure has been compromised due to insect pest infestations.

Experimental Study on a Passive Solar Desalination Unit Associated With Fresnel Lens and Thermal Storage

Passive solar stills can be a viable source of freshwater in water and energy scarce regions. However, the low production rate is one of the major drawbacks of passive solar stills. This work presents an experimental study of the combined effects of concentrated solar power (CSP) and phase change material (PCM) on a low-cost double slope passive solar desalination unit. Fresnel lens as the refractive CSP was used to converge the available solar irradiation onto the solar still basin that contained saline water. Metal tubes containing petroleum jelly with a melting point of 37°C were immersed as the PCM in the saline water. Four different experimental setups were tested in the natural tropical weather of Malaysia to identify the individual and combined impact of the lens and petroleum jelly on desalination performance. It was observed that the performance was better with the individual application of the CSP rather than the combination of CSP and PCM. There was a 28.21 % improvement in distillate production using Fresnel lens only; while using the Fresnel lens and PCM in combination showed a 25.64 % improvement in production. This study also provides several recommendations with which the experimental setup can be improved to yield better results in the future.