Distribution network automation is considered by power supply companies as an effective investment strategy to improve reliability and service quality. Switching devices and protective devices play an important role in the distribution automation system (DAS). This paper presents a novel method to optimize placement of fault indicators and sectionalizing switches in distribution networks with branch lines. The objective function of the proposed method includes the total cost of fault indicators and sectionalizing switches as well as interruption cost. Among different automation equipment, this paper considers fault indicators and remote controlled switches. Besides, manual switches are taken into account since their number and location have a significant impact on the optimal placement problem. Mixed-integer linear programming is used to model the problem, and the proposed model can be solved by large-scale commercial solvers. The solution to the problem is composed of the optimal number and location of fault indicators and sectionalizing switches. The validity of the proposed method is demonstrated by relevant case studies and sensitivity analysis. Moreover, the proposed method is applied to a real distribution network to verify its practicability. INDEX TERMS Fault indicator (FI), manual switch (MS), remote controlled switch (RCS), mixed-integer linear programming (MILP), reliability, distribution network.
A modified QuEChERS method using a GC-ECD to determine the multiple residues of pyraclostrobin, difenoconazole, dimethomorph and azoxystrobin and to indirectly determine the total residues of maneb, mancozeb and propineb by a GC-FPD (with an S filter) was established and validated. Meanwhile, field trials were conducted in accordance with good agricultural practice (GAP) to study their characteristics of residue degradation under the agricultural climate and cropping system of Guangxi Province. The separation effect of each target peak was good with a linearity range of 0.01–5 mg L−1, a limit of detection (LOD) of 0.003–0.015 mg kg−1 and a limit of quantification (LOQ) of 0.01–0.05 mg kg−1. The average recovery ranges of vegetable tomatoes and cherry tomatoes were 70.5–120.0% and 70.8–119.8%, respectively, with relative standard deviations (RSDs) of less than 7.1%. Field trials of seven fungicides in vegetable and cherry tomatoes showed that the half-lives (t 1/2 ) of the dithiocarbamate fungicides (metiram, mancozeb, and propineb, defined as total residues determined as CS2), pyraclostrobin, difenoconazole, dimethomorph, and azoxystrobin were in the ranges of 5.2, 12.7–17.8, 7.6–7.9, 6.6–6.9, and 6.3–6.6 d in vegetable tomatoes, respectively. The cherry tomatoes presented ranges of 4.3–4.5, 10.8–11.8, 6.7–7.0, 5.4–5.5, and 5.9–6.2 d, respectively. Combined with the final residue and market monitoring results, the results show that cherry tomatoes have significantly higher terminal residues, initial deposits, and maximum residues of seven fungicides than vegetable tomatoes, and these seven pesticides can be detected in cherry tomatoes purchased from three markets. Therefore, cherry tomatoes may be regarded as representative varieties of tomatoes in realizing residual extrapolation for the establishment of the maximum residue limit (MRL) value of fungicides in tomatoes and for conducting market monitoring.
In order to solve the control of the degree of anti-occlusion of the roadside landscape of the expressway curve according to the drivers’ visual characteristics during high-speed driving, a dynamic space model of the visual process of curved highway roadside landscape was established, and the calculation equation of roadside landscape visual field was derived. The dynamic occlusion ratio was defined by space coordinates, and the judgment model was proposed for the de-occlusion of the roadside landscape visual field. According to the standard design parameters of the G4 Highway Hunan section, the occlusion laws were analyzed by MATLAB for different widths and different heights of obstructions as well as the same widths and heights of obstructions at different positions in the roadside landscape visual field, thus the control value and control content of anti-occlusion clearance for the roadside landscapes were proposed. The results show that the anti-occlusion clearance control range of the roadside landscape is 270 m at the design speed of 120 km/h, 220 m at 100 km/h, and 170 m at 80 km/h. The control value of clearance width is 25 m, and the control value of clearance height is recommended to be 20 m. Within the scope of highway land expropriation, it is recommended to land expropriation 25 m wide from the road boundary. The research provides model support for building the closeness and openness of highway roadside landscape.
Nonthermal air plasma, which can be generated by air discharge, contains large amounts of reactive oxygen species (ROS), reactive nitrogen species (RNS) and high-energy particles. The ROS and RNS have strong oxidizing properties, and the high-energy particles can break chemical bonds in organic compounds, a process which can be used to degrade organic matter such as pesticides. In the present study, the effects of nonthermal air plasma on the degradation of several pesticides were investigated. An air plasma processing system was designed and constructed to produce nonthermal air plasma and to degrade five commonly used acaricides, namely, avermectin, bifenazate, spirodiclofen, etoxazole, and lufenuron, during the production of kumquat cuimi. The experimental results showed that nonthermal air plasma could degrade all the acaricides on the surface of the kumquat cuimi effectively. After 20 min of plasma treatment, the residues of avermectin, bifenazate, spirodiclofen, etoxazole and lufenuron on the surface of the kumquat cuimi were reduced by 80.67%, 79.52%, 62.40%, 48.93% and 23.11%, respectively. Further analysis indicated that the primary chemical bonds, hydrophobicity, and the pH value of the plasma-activated water can all affect the efficiency of pesticide degradation.
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