In the general form of the curve for the rate of drying of a solid shown in Figure 16.2, there are two and sometimes three distinct sections. During the constant-rate period, moisture vaporises into the air stream and the controlling factor is the transfer coefficient for diffusion across the gas film. It is important to understand how the moisture moves to the drying surface during the falling...

Moisture diffusion in multi-layer carbon composite structures is difficult to model using finite difference methods due to the discontinuity in concentrations between adjacent layers of differing materials. Applying a mass conserving approach at these boundaries proved to be effective at accurately predicting moisture uptake for a sample exposed to a fixed temperature and relative humidity. Det...

rice is one of the most widely human consumed agricultural products. for a prevention or diminishing of rice cracking in its milling process, precision control of drying conditions is indispensable. in this research, a thin layer experimental dryer is employed to obtain paddy’s drying kinetics. drying experiments were conducted at five inlet temperatures of drying air of 30, 40, 50, 60 and 70 °...

Humidity change in concrete is the leading cause of shrinkage. Moreover, moisture diffusion coefficient an essential parameter for assessing and predicting internal content concrete. However, there a lack theoretical construction experimental studies on effect different conditions, especially constraints, Therefore, humidity, pore structure parameters, basic mechanical properties under strength...

Pulsed field gradient (PFG) nuclear magnetic resonance (NMR) has been used to study self-diffusion characteristics of water and oil in natural peanuts and in peanuts saturated with water. From the dependence on diffusion time of the echo decay due to diffusion, regions of completely restricted diffusion for the oil molecules were identified. The mean size and size distribution function of these...

introduction drying foods, fruits and vegetables is a suitable method to reduce post-harvest losses of the crops. drying is considered as a simultaneous heat and mass transfer process. various physical, chemical and nutritional changes occur during drying of foods and are affected by a number of internal and external heat and mass transfer parameters. external parameters may include temperature...

Experiments have been carried out to study the influence of moisture condition, including moisture content and its distribution, on the chloride diffusion in partially saturated ordinary Portland cement mortar. The mortar samples with water-to-cement (w/c) ratios of 0.4, 0.5 and 0.6, cured for one year, were preconditioned to uniform water saturations ranging from 18% to 100%. The interior rela...