Th e drying characteristics of “Granny Smith” apples were analysed using a tunnel drier at diff erent temperatures and diff erent pre-treatments. „Granny Smith“ apples were cut into rectangle-shaped samples 20x20x5 mm in size. Th e drying temperatures for non-treated samples varied from 50oC to 80oC at airfl ow velocity of 2.8 m s-1. Prior to drying at 60oC, the samples were pretreated either t...

The effect of microwave-assisted convective air-drying on the drying kinetics and quality of mango was evaluated. Both microwave power and pretreatment time were significant factors but the effect of power was more profound. Increase in microwave power and pretreatment time had a positive effect on drying time. The nonenzymatic browning index of the fresh samples increased from 0.29 to 0.60 whi...

ammonium perchlorate particles have been dried in a laboratory spouted bed dryer (screen-bottomed type) which is categorized as a fluidized bed dryer. the solid particles obtained in this process of drying were semi-porous and known as the group d of geldart classification. the variations of moisture content with resident time, the effects of bed height on the pressure drop, and the influence o...

Drying kinetics of Cape gooseberry was studied and modeled during processing at four temperatures (60, 70, 80 and 90C). Desorption isotherm was obtained at 40C giving a monolayer moisture content of 0.086 g water/g d.m. Experimental drying curves showed that drying process took place only in the falling rate period. Several thin-layer drying models available in the literature were evaluated bas...

In the present work a diffusion based model was adopted to represent the drying behaviour of pears in a continuous convective drier, taking into consideration the variation of the properties of the pears along drying. The program developed simulated a significant number of situations resultant from the variation of some of the operating conditions. The temperatures tested were 30, 40 and 50 C, ...

Osmotic drying is a process of partial removal of water by submersing fruits in sucrose solution. Th e goal of this paper is to examine kinetic features of osmotic drying of apricot halves in sucrose solution. For osmotic drying of apricot halves in a thick immovable layer, a planned experiment was conducted. Experimental results were used to create an empirical model of osmotic drying kinetics...

An unstructured finite volume numerical model is presented here for simulating shallow-water flows with wetting and drying fronts. The model is based on the Green’s theorem in combination with Chorin’s projection method. A 2-order upwind scheme coupled with a Least Square technique is used to handle convection terms. An Wetting and drying treatment is used in the present model to ensures the to...

Sessile droplets of aqueous poly(ethylene oxide) solution, with average molecular weight of 100 kDa, are monitored during evaporative drying at ambient conditions over a range of initial concentrations c(0). For all droplets with c(0) > or = 3%, central conical structures, which can be hollow and nearly 50% taller than the initial droplet, are formed during a growth stage. Although the formatio...

A mathematical model of the coupled heat and mass transfer has been developed to calculate the drying process in a mixed-flow grain dryer. Periodical discharge operation of the dryer causes strong variations of temperature and moisture of the material. A series of quasi-stationary drying experiments have been carried out. These results are used to test and to improve the dryer model. The calcul...

this is the first attempt at process modeling in terms of predictive control using a hierachical method based on regression analysis and artificial neural networks (anns). this hierachical method leads to the reliability improvement of neural model of the process in predicting (extrapolation and interpolation) the process output. such an outlook makes it possible to predict the proper input set...