The drying of grapes is a more complex process compared to the dehydration of other agricultural materials due to the necessity of a pretreatment operation prior to drying. Grape drying to produce raisins is a very slow process, due to the peculiar structure of grape peel, that is covered by a waxy layer. Its removal has been so far carried out by using several chemical pre-treatments. However,...

As wood shrinks during the drying process, various stresses may develop and cause surface and internal checking. The aim of this study was to systematically investigate the effect of the drying temperature, relative humidity, and specimen thickness on the contraction stress in elm wood (Ulmus pumila L.) specimens during drying. The contraction stress was used as an indirect indicator of drying ...

In Central Europe the main species that are used for the production of sawn wood are spruce, pine, and European beech. After the sawing process, the sawn timber is technically dried to a certain moisture content by means of condensation drying. The water movement in the cellular structure, which is caused by the drying process, draws some of the extractives into solution. In the process of kiln...

Porous medium vacuum drying is a complicated heat and mass transfer process. Based on the theory of heat and mass transfer, a coupled model for the porous medium vacuum drying process is constructed. The model is implemented and solved using COMSOL software. The water evaporation rate is determined using a nonequilibrium method with the rate constant parameter Kr. Kr values of 1, 10, 1000, and ...

The modelling and simulation of drying porous coal particles in superheated steam was investigated in this paper. Improved transport and kinetic parameters as well as particle shrinkage were considered in arriving at the results. The resulting partial differential equation describing the drying process was solved numerically using the finite element analysis in addition to other useful equation...

Rapid drying can increase brittleness and induce internal cracks which predispose the product to breakage during subsequent activities. The drying process must be understood and controlled so that design guidelines which reduce or minimize drying damage to rough rice can be established and improved. This study is to give a mathematical model with numerical solution to follow the mass distributi...

Since Shackell (1909) described the preservation of biological material by freeze-drying, or drying by sublimation of ice, other workers have improved the process until, at the present time, it is used to preserve a variety of biological products. Flosdorf (1949) has reviewed the course of this development. A few of the workers in the field have published the results of attempts to use this tec...

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in this study the efficacy of intermittent and continuous drying processes on fissuring of hashemi and koohsar varieties was investigated. the fissuring of the kernels was assessed based on stress cracking index (sci). the experiments were carried out at drying and tempering temperatures of 30, 45 and 60 °c, drying durations of 20, 40 and 60 min, and constant tempering duration of 80 min. in co...