Modeling of drying kinetic of pretreated sour cherry.
The effects of pretreatment solution (dipping in boiling water, salty boiling water, ethil oleat) were studied on drying kinetic of sour cherry. The thin-layer drying of sour cherries were carried out at three air temperatures of 50, 60 and 70°C and airflow velocity of 1 m/s. The experimental data were fitted to several thin-layer drying models such as Newton, Henderson and Pabis, Page, Logarithmic, Approximate Diffusion, Two-term exponential, and Midilli et al.. Three statistical tools coefficient of determination (R2), reduced chi-square (x2) and root means square error (RMSE) were used to quantify the goodness of fit. According to the results, drying time of sour cherry samples dipped in salty boiling water solution was shorter than the pretreated samples and control treatments. Besids, The Midilli et al. and Logarithmic models were found to be most suitable in describing the drying characteristics of sour cherry respectively. The effective moisture diffusivity of sour cherries based on the analytical solution of Fick’s second law ranged from 2.07×10-11 to 2.33×10-10 m2/s. Using of pretreated solutions caused to decreasing activation energy in sour cherry drying process. Activation energy values varied from 23.74 to 83.05 kJ/mol.
Influence of pretreatment solution on the drying of sour cherry
Abstract The effect of alkali ethyl oleate solution (AEEO) on drying time of sour cherry was studied experimentally. The thin-layer drying of sour cherries was carried out under two air temperatures of 55 and 65 °C at a constant airflow velocity of 1 m/s. Drying time of pretreated samples was about 26–30% shorter than that of untreated samples. The experimental moisture loss data were fitted to select semi-theoretical and empirical thin-layer drying models, namely, Lewis, Henderson and Pabis, Page, Logarithmic, Two-term, Two-term exponential, Wang and Singh, and Midilli et al. models. Three statistical tools were used to quantify the goodness of fitting: the coefficient of determination ( R 2 ), reduced chi-square ( χ 2 ) and root means square error (RMSE). R 2 , χ 2 and RMSE values of all models were compared, it was concluded that the Midilli et al. and Logarithmic models were found to be most suitable in describing the drying characteristics of sour cherry. Effective moisture diffusivity of sour cherries based on analytical solution of Fick’s second law ranged from 4.75 × 10 −10 to 1.03 × 10 −9  m 2 /s.
Experimental study of water fluxes in a residential area: 2. Road infiltration, runoff and evaporation
Lack of accurate data has led some hydrologists and city planners to assume that urban infiltration is zero and runoff is 100% of the rainfall. These assumptions lead to an over estimation of road runoff volume and an underestimation of direct recharge to groundwater, which is already rising under some UK cities. This study investigates infiltration and runoff processes and quantifies the percentage of rainfall that contributes to storm drainage, and that which infiltrates through different types of road surface. Access tubes were installed for measuring soil water content using a neutron probe in three car parks, a road and a grass site at the Centre for Ecology and Hydrology, Crowmarsh Gifford, Wallingford. Storm drainage was recorded at the exit of the Thamesmead Estate in Crowmarsh Gifford, just before the drain joins the River Thames at Wallingford. Rainfall and water table depth were also recorded. Weekly measurements of soil moisture content indicated that the top 40 cm layer is not influenced by water‐table fluctuations and, therefore, positive changes in soil moisture could be attributed to infiltration of rainfall through the surface. Depending on the nature of the surface, subsurface layers, level of traffic, etc., between 6 and 9% of rainfall was found to infiltrate through the road surfaces studied. The storm drainage generated by road runoff revealed a flow pattern similar to that of the receiving watercourse (River Thames) and increased with the increase of infiltration and soil water content below the road surface. The ratio of runoff to rainfall was 0·7, 0·9 and 0·5 for annual, winter (October–March) and summer (April–September) respectively. As the results of the infiltration indicated that 6 to 9% of annual rainfall infiltrates through the road surface, this means that evaporation represents, 21–24% of annual rainfall, with more evaporation taking place during summer than winter. Copyright © 2003 John Wiley & Sons, Ltd.