Effect of scattering extinction coefficient on drying rate

Abstract

Drying is purposely meant for preservation at lowest possible cost. The methods of drying can be categorized into two broad headings - Natural and Artificial. In the natural drying method, solar radiation is the major factor required. It has been observed that less than 30% of the radiation from the sun actually reaches the earth surface, the rest are reflected or scattered by the particles of the media through which it passes. As human activities on the earth surface increase, more panicles are released into the atmosphere and hence the rate at which the solar radiation is scattered (or extinct) is at increase. The rate at which the solar radiation reaching the earth surface is scattered was hypothetically measured by drying moist produce in a semi-closed solar drier. The evaporated moisture (forming smog) from the produce was used as the hypothetical atmospheric particles. The effect of this radiation scattering (scattering extinction coefficient, or kvalue) on the drying rate was observed. It was noted that the k-value increases as the amount of particles are increased, and this led to a decrease in drying rate. It was adjudged that, has more particles are released into the atmosphere more radiation will be scattered and drying rate of produce will be reduced. This effect is not known at present due to the general global warming resulting from ozone depletion.