The Optimal Sizing of Substation Capacity in a Distribution Network, Considering a Dynamic Time-of-Use Pricing Mechanism.

Application of sensors in the smart grid has promoted the development of demand side management (DSM). However, the incentives of DSM such as peak-valley time-of-use (TOU) price will change the load pattern in the future; the substation capacity sizing will be further influenced accordingly. This paper proposes a substation capacity sizing method in distribution network considering DSM and establishes a peak-valley TOU pricing method based on the cost-benefit analysis of each participant in the TOU price. Compared with the conventional fixed peak-valley ratio, a dynamic division method is proposed to calculate the optimal pull-off ratio for the TOU pricing. By considering the proposed TOU pricing method, a substation capacity sizing model for the distribution network is further proposed. Finally, the economic benefits of the two substation capacity sizing schemes are compared and evaluated according to the selected economic indicators. The results of the case study demonstrate that under the premise of reasonable pricing, considering the impact of TOU on substation capacity sizing, the construction investment and the user cost of power supply companies can be saved while meeting the power demand. The economy and rationality of the planning scheme have been significantly improved.

Hydroxyl radical-based and sulfate radical-based photocatalytic advanced oxidation processes for treatment of refractory organic matter in semi-aerobic aged refuse biofilter effluent arising from treating landfill leachate.

In this study, three photolytic advanced oxidation processes (AOPs) were applied to the treatment of refractory organic matter in semi-aerobic aged refuse biofilter (SAARB) effluent, and the treatment efficiencies of the three AOPs were systematically compared. The AOPs combined ultraviolet (UV) radiation with either hydrogen peroxide (UV-H2O2), peroxymonosulfate (UV-PMS) or both oxidants (UV-PMS/H2O2). The effects of key parameters on degradation characteristics of refractory organics, and the contribution of reactive oxygen species were systematically studied. Results indicated that UV radiation can greatly enhance treatment efficiencies of both PMS and H2O2. Furthermore, decreasing n(H2O2)/n(PMS) ratio and decreasing the reaction pH can increase treatment efficiency for refractory organics. Compared on the basis of chemical oxygen demand (COD), treatment efficiency followed the order UV-PMS (COD removal 37.39%) > UV-PMS/H2O2 (30.51%) > UV-H2O2 (28.59%) which is consistent with results from ultraviolet-visible spectra analysis. HO• and SO4•- were both identified in the UV-PMS/H2O2 and UV-PMS processes. In the UV-PMS process, SO4•- was the dominant ROS, which suggested that SO4•--based AOPs are better than HO•-based AOPs for degrading refractory organics contained in SAARB effluent. Parallel factor (PARAFAC) analysis indicated that UV-based AOPs were effective in degrading humic- and fulvic-like substances in the SAARB leachate, and the UV-PMS process achieved a much better degradation efficiency of refractory organics in the leachate than did the UV-PMS/H2O2 and the UV-H2O2 processes. Furthermore, the best treatment efficiency was achieved by the UV-PMS process and this process also consumed the least electrical energy. This study provides a theoretical reference for refractory organics degradation in SAARB effluent by UV-catalyzed AOPs.

Inhibitory effects of components from root exudates of Welsh onion against root knot nematodes.

Root-knot nematodes (RKNs; Meloidogyne spp.) are obligate endoparasites that infect many crops and cause severe yield losses. In this research, we studied the effect of Welsh onion, grown as a companion plant, on the resistance of cucumber plants to RKN infection and analyzed the most abundant components of Welsh onion root exudates. The results showed that, when grown with Welsh onion as a companion plant, cucumber roots had 77.0% fewer root knots and egg masses than the control cucumber roots. Welsh onion root exudates were collected and extracted with chloroform, ethyl ether, n-butanol and ethyl acetate. High concentrations of the extracts from the Welsh onion root exudates decreased the hatchability of RKN eggs. In particular, the inhibitory effect of the n-butanol extract was significant and the hatchability of RKN eggs did not exceed 10%. Gas chromatographic-mass spectrometric analysis revealed that the most abundant component in the n-butanol extract was 4-hydroxy-benzeneethanol. Treatment with 1.2 mM 4-hydroxy-benzeneethanol decreased egg hatchability to 40%, whereas treatment with 9.6 mM or a higher concentration of 4-hydroxy-benzeneethanol decreased egg hatchability to less than 10%. In addition, 1.2 mM or a higher concentration of 4-hydroxy-benzeneethanol decreased the activity of the second-stage juvenile (J2). Higher 4-hydroxy-benzeneethanol concentrations (9.8 and 19.2 mM) were lethal to RKNs to some extent, with death rates greater than 50% at 48 h of treatment. The present results suggest that cultivation with Welsh onion as a companion plant may represent an alternative to the application of synthetic nematicides, with fewer side effects. We confirmed that 4-hydroxy-benzeneethanol is a natural effective nematicide.