Abdulrahim M. Al-Ismaili

Effect of carrier agents on physicochemical properties of foam-mat freeze-dried date powder

ABSTRACT Date powder was produced by foam-mat freeze-dried method without and with carrier agents (maltodextrin and gum arabic) at two concentration levels (40 and 50%). The effect of carrier agents on the physicochemical properties of powder, i.e., hygroscopicity, degree of caking, wettability, dispersibility, solubility, water absorption index, color, and total phenolic content was investigated. Carrier agent-added date powders had lower hygroscopicity that offers good storage stability. Maltodextrin-added powders had lower wettability and higher solubility which indicate good reconstitution properties. The hygroscopicity, degree of caking, wettability, and total phenolic content significantly decreased with an increase in carrier concentration level.

Empirical model for the condenser of the seawater greenhouse

ABSTRACT Seawater greenhouses (SWGH) utilize seawater or saline/brackish groundwater for cooling the microclimate and providing freshwater for irrigation through a humidification–dehumidification desalination process. The overall effectiveness of the SWGH greatly depends on the effectiveness of its condenser. The present study provides a good review on the available simulation models of the SWGH condenser and proposes a multiple linear regression model to predict the dehumidification rate of the condenser in the Oman SWGH. Four climatic and operational input variables were considered, including solar irradiance, inlet moist air temperature, inlet humidity ratio, and inlet air mass flow rate. The results showed that the model accurately predicts the dehumidification rate when compared against experimental values [a mean predictive error (PE) = −0.127 kg/h and root mean square error (RMSE) = 4.691 kg/h]. The model also outperformed some other model in several accuracy indicators such as PE, mean absolute predictive error, RMSE, R2, index of agreement and fractional variance.