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As a measure to enhance drying kinetics, efficiency, and quality of the whole American ginseng root, step-down relative humidity (RH) convective hot air drying strategy was experimentally investiga...

The current work presents energy efficient hot air drying by controlling the relative humidity (RH) including step-down and continuous dehumidification of RH as to specify material based on Weibull and Bi-Di models. The drying characteristics of yam slices of different thickness (6, 12, 18 mm) and longan were investigated using two RH control strategies. Results showed that continuous decrease of RH was energy efficient for longan, while the step-down strategy was more energy efficient for 12 or 18 mm thick yam slices drying. In terms of drying kinetics, the step-down control strategy of RH is more energy efficient for those materials whose drying rate as well as sample’s temperature curves display three distinct stages and sample thickness is relative large. In terms of β and Bi values in Weibull and Bi-Di models respectively, it is observed that the step-down control strategy of RH drying method is more efficient when the β value exceeds 1 and the Bi value was more than 0.1. The current investigation provided an assessment method for the convective hot air drying method by controlling RH to improve drying efficient and save energy consumption.

The enhancement of device performance achieved by inserting a LiF (lithium fluoride) interfacial layer between the active layer and aluminum (Al) cathode was investigated. Energy band diagrams and interfacial chemical reactions were examined using high-resolution synchrotron-radiation photoemission spectroscopy. If only a thin layer of Al is deposited on the P3HT:PCBM/LiF, the highest occupied molecular orbital level of the active layer does not change. This indicates that shifts in the energy band are only strongly influenced by the insertion of LiF, not the subsequent deposition of an Al layer. We found that the molecular energy band shifts occurred at the interface because of the presence of LiF increases the open-circuit voltage. Furthermore, the thin layer of LiF reduces the work function and improves contact with the cathode, thereby reducing the series resistance and improving the short circuit current density. Thus, without the influence of the Al layer, inserting LiF improves the device performance. The level of performance differs substantially from that observed at the organic layer/LiF/Al interfaces in organic light-emitting devices.

In this study, the strain Trichoderma reesei SEMCC-3.217 was used for producing cellulase in solid-state fermentation with water hyacinth ( Eichhornia crassipes ). The results of fractional factorial design showed that, the addition amount of wheat bran, (NH 4 ) 2 SO 4 , CaCl 2 and Tween 80 had significant effect on the cellulase production. Then, these four factors were selected for further optimization by central composite design for the yield of cellulase. The statistical analysis of the results showed that, the optimum composition were: 5 g of substrate containing 3.9 g water hyacinth, 1% corn steep liquor, 1% soybean meal, 0.2% NH 4 NO 3 , 0.2% KH 2 PO 4 , 0.08% MgSO 4 ·7H 2 O, 2.8% (NH 4 ) 2 SO 4 , 1.5% urea, 13.9% wheat bran, 0.08% ZnSO 4 ·7H 2 O, 0.08% FeCl 2 0.05% CaCl 2 , 0.08% NaNO 3 , 0.08% KCl and 0.27% (v/v) Tween-80. Under these conditions, the cellulase production was 4-fold increased (13.4 FPIU/g dry solid) compared with the initial level (3.4 FPIU/g dry solid) after 7 days of fermentation in a 250 ml Erlenmeyer flask. Key words : Cellulase, solid-state fermentation, optimization, water hyacinth, Trichoderma reesei.