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Four different drying methods, namely, air drying (AD), microwave-assisted vacuum drying (MWVD), coupled microwave–hot air drying (MWAD), and freeze drying (FD), were studied, in terms of drying time, color, reducing sugar content, shrinkage, microstructure, and sensory evaluation. The drying rate of MWVD and MWAD were notably faster than that of AD and FD. The highest reducing sugar content was observed in MWAD, followed by MWVD. No significant differences were observed in reducing sugar between air-dried and freeze-dried products. FD had the best color and shrinkage among the other drying methods. The color and shrinkage of MWVD drying is close to the fresh litchis and much better than hot air and MWAD. Scanning electron microscopy (SEM) images showed that the MWVD and FD litchis have a porous structure, whereas AD and MWAD litchis have a compact structure. The sensory evaluation suggests that peeled litchis dried by the four studied drying methods are of a quality that is accepted by consumers. [ABSTRACT FROM PUBLISHER]

In this paper, the unsteady characteristics of tip leakage flow in axial fans with circumferential skewed blades were investigated at off-design conditions using wall pressure test. The static pressure fluctuations near blade tip were captured at off-design conditions by using pressure sensors mounted on casing wall. From the measured results, instantaneous characteristics of tip leakage flow in circumferential skewed fans were analyzed. Based on the measurement results, as the flow rate decreases, the broadband frequency components of tip leakage flow tend to increase in the low frequency domain. The forward-skewed blade is found to be effective in controlling tip leakage flow to expand from blade leading edge to tail edge, the TLF component of the BSK rotor propagates more fast than that of FSK rotor. The instability of tip leakage flow under off-design conditions is controlled by circumferential skewed blades. [ABSTRACT FROM AUTHOR]

Surface soil samples around Guanting Reservoir ranging from 2-10 km were measured for pesticide residues (HCHs and DDTs) concentrations in 2009. Occurrences and related environmental risk were analyzed; furthermore, GIS and geostatistical techniques were applied to analyze the spatial variation of organochlorine pesticides. The results show that concentrations of HCHs in soils range from n.d. to 14.97 ng x g(-1) with a mean value of 0.73 ng x g(-1), and DDTs range from n.d. to 64.91 ng x g(-1) with a mean value of 6.46 ng x g(-1). According to the isomers of HCHs and metabolites of DDTs, HCHs and DDTs residues in soils were primarily from historical use. The land use showed great effect on the degradation of HCHs and DDTs, with the residual level sequence of orchard >> crop land > barren land. Based on kriging interpolation, the spatial distribution of HCHs and DDTs around Guanting Reservoir was observed. Spatial variability indicated how HCHs and DDTs had been applied and distributed in the past. Compared with those in other national or international regions, the concentrations of HCHs and DDTs in soils around Guanting Reservoir were very low.