For which one of the following situations would Kendall’s tau be appropriate? a) The Mohs scale rates the hardness of minerals. If one mineral can scratch another, it is judged….
Calculate the free moisture content X kg H2O/kg dry solid for each data point and plot X versus time.
Drying Tests with a Foodstuff. In order to test the feasibility of drying a certain foodstuff, drying data were obtained in a tray dryer with air flow over the top exposed surface having an area of 0.186 m2. The bone-dry sample weight was 3.765 kg dry solid. At equilibrium after a long period, the wet sample weight was 3.955 kg H2O + solid. Hence, 3.955 – 3.765, or 0.190, kg of equilibrium moisture was present. The following sample weights versus time were obtained in the drying test:
a. Calculate the free moisture content X kg H2O/kg dry solid for each data point and plot X versus time. (Hint: For 0 h, 4.944 – 0.190 – 3.765 = 0.989 kg free moisture in 3.765 kg dry solid. Hence, X = 0.989/3.765.)
b. Measure the slopes, calculate the drying rates R in kg H2O/h · m2, and plot R versus X.
c. Using this drying-rate curve, predict the total time to dry the sample from X = 0.20 to X = 0.04. Use numerical integration for the falling-rate period. What are the drying rate RC in the constant-rate period and XC?