Reactive power planning for regional power grids based on active and reactive power adjustments of DGs

To deal with extreme overvoltage scenarios with small probabilities in regional power grids, the traditional reactive power planning model requires a huge VAR compensator investment. Obviously, such a decision that makes a large investment to cope with a small probability event is not economic. Therefore, based on the scenario analysis of power outputs of distributed generations and load consumption, a novel reactive power planning model considering the active and reactive power adjustments of distributed generations is proposed to derive the optimal allocation of VAR compensators and ensure bus voltages within an acceptable range under extreme overvoltage scenarios. The objective of the proposed reactive power planning model is to minimize the VAR compensator investment cost and active power adjustment cost of distributed generations. Moreover, since the proposed reactive power planning model is formulated as a mixed-integer nonlinear programming problem, a primal-dual interior point method-based particle swarm optimization algorithm is developed to effectively solve the proposed model. Simulation results were conducted with the modified IEEE 30-bus system to verify the effectiveness of the proposed reactive power planning model

Ectopic tissue engineered ligament with silk collagen scaffold for ACL regeneration: A preliminary study

Anterior cruciate ligament (ACL) reconstruction remains a formidable clinical challenge because of the lack of vascularization and adequate cell numbers in the joint cavity. In this study, we developed a novel strategy to mimic the early stage of repair in vivo, which recapitulated extra-articular inflammatory response to facilitate the early ingrowth of blood vessels and cells. A vascularized ectopic tissue engineered ligament (ETEL) with silk collagen scaffold was developed and then transferred to reconstruct the ACL in rabbits without interruption of perfusion. At 2 weeks after ACL reconstruction, more well-perfused cells and vessels were found in the regenerated ACL with ETEL, which decreased dramatically at the 4 and 12 week time points with collagen deposition and maturation. ACL treated with ETEL exhibited more mature ligament structure and enhanced ligament-bone healing post-reconstructive surgery at 4 and 12 weeks, as compared with the control group. In addition, the ETEL group was demonstrated to have higher modulus and stiffness than the control group significantly at 12 weeks post-reconstructive surgery. In conclusion, our results demonstrated that the ETEL can provide sufficient vascularity and cellularity during the early stages of healing, and subsequently promote ACL regeneration and ligament-bone healing, suggesting its clinic use as a promising therapeutic modality. Statement of Significance Early inflammatory cell infiltration, tissue and vessels ingrowth were significantly higher in the extra articular implanted scaffolds than theses in the joint cavity. By mimicking the early stages of wound repair, which provided extra-articular inflammatory stimulation to facilitate the early ingrowth of blood vessels and cells, a vascularized ectopic tissue engineered ligament (ETEL) with silk collagen scaffold was constructed by subcutaneous implantation for 2 weeks. The fully vascularized TE ligament was then transferred to rebuild ACL without blood perfusion interruption, and was demonstrated to exhibit improved ACL regeneration, bone tunnel healing and mechanical properties. (C) 2017 Published by Elsevier Ltd on behalf of Acta Materialia Inc

Genome-wide association study of lung adenocarcinoma in East Asia and comparison with a European population

Lung adenocarcinoma is the most common type of lung cancer. Known risk variants explain only a small fraction of lung adenocarcinoma heritability. Here, we conducted a two-stage genome-wide association study of lung adenocarcinoma of East Asian ancestry (21,658 cases and 150,676 controls; 54.5% never-smokers) and identified 12 novel susceptibility variants, bringing the total number to 28 at 25 independent loci. Transcriptome-wide association analyses together with colocalization studies using a Taiwanese lung expression quantitative trait loci dataset (n = 115) identified novel candidate genes, including FADS1 at 11q12 and ELF5 at 11p13. In a multi-ancestry meta-analysis of East Asian and European studies, four loci were identified at 2p11, 4q32, 16q23, and 18q12. At the same time, most of our findings in East Asian populations showed no evidence of association in European populations. In our studies drawn from East Asian populations, a polygenic risk score based on the 25 loci had a stronger association in never-smokers vs. individuals with a history of smoking (P interaction  = 0.0058). These findings provide new insights into the etiology of lung adenocarcinoma in individuals from East Asian populations, which could be important in developing translational applications

Genome-wide association study of lung adenocarcinoma in East Asia and comparison with a European population.

Lung adenocarcinoma is the most common type of lung cancer. Known risk variants explain only a small fraction of lung adenocarcinoma heritability. Here, we conducted a two-stage genome-wide association study of lung adenocarcinoma of East Asian ancestry (21,658 cases and 150,676 controls; 54.5% never-smokers) and identified 12 novel susceptibility variants, bringing the total number to 28 at 25 independent loci. Transcriptome-wide association analyses together with colocalization studies using a Taiwanese lung expression quantitative trait loci dataset (n = 115) identified novel candidate genes, including FADS1 at 11q12 and ELF5 at 11p13. In a multi-ancestry meta-analysis of East Asian and European studies, four loci were identified at 2p11, 4q32, 16q23, and 18q12. At the same time, most of our findings in East Asian populations showed no evidence of association in European populations. In our studies drawn from East Asian populations, a polygenic risk score based on the 25 loci had a stronger association in never-smokers vs. individuals with a history of smoking (Pinteraction = 0.0058). These findings provide new insights into the etiology of lung adenocarcinoma in individuals from East Asian populations, which could be important in developing translational applications

A Preventive Strategy of Voltage Stability based on Characteristic Analysis

The purpose of voltage stability prevention and control strategy is to minimize the impact of expected accidents on the whole power grid while ensuring safe power supply. In this paper, it is expected that the accident has a large impact on the system voltage and makes the voltage margin of each node low. in order to not only adjust the node voltage, but also reduce the disturbance impact, a voltage stability prevention and control strategy is proposed based on the characteristic analysis

Mixed nitrifying bacteria culture under different temperature dropping strategies: Nitrification performance, activity, and community

In this study, the nitrification performance, metabolic activity, antioxidant enzyme activity as well as bacterial community of mixed nitrifying bacteria culture under different temperature dropping strategies [(#1) growth temperature kept at 20 degrees C; (#2) sharp1 decreased from 20 degrees C to 10 degrees C; (#3) growth at 20 degrees C for 6 days followed by sharp decrease to 10 degrees C; and (#4) gradual decreased from 20 degrees C to 10 degrees C] were evaluated. It was shown that acclimation at 20 degrees C for 6 days allowed to maintain better nitrification activity at 10 degrees C. The nitrite oxidation capacity of nitrifiers was significantly correlated with the relative light unit (RLU) (p<.05) and the fluctuation of superoxide dismutase (SOD) enzyme activity (p<.01). With serial #3 showed the highest RLU levels and the least SOD enzyme fluctuation as compared to serials #2 and #4. Throughout the experimental period, Nitrosospira and Nitrosomonas as well as Nitrospira were identified as the predominant ammonia-oxidizing bacteria (AOB) and nitrate-oxidizing bacteria (NOB). The dynamic change of AOB/NOB ratios and nitrification activity in serials #2-#4 demonstrated that AOB recovered better than NOB with long-term 10 degrees C exposure, and the nitrification performance was mainly limited by the nitrite oxidation capacity of NOB. Applying 6 days acclimation at 20 degrees C was beneficial for the mixed nitrifying bacteria culture to cope with low temperature (10 degrees C) stress, possibly due to the maintenance of metabolic activity, antioxidant enzyme activity stability as well as appropriate AOB/NOB ratio. (C) 2017 Elsevier Ltd. All rights reserved

Rapid analysis of sludge concentration using a microwave-assisted heating method: Parameters, modelling, and application

In this paper, the parameters, models, and application of a microwave-assisted heating (MWAH) method for rapid analysis of sludge concentration were studied. For activated/physicochemical sludge concentrations (2000-4000 mg/L) analysis, the feasible parameters using a MWAH method were microwave drying time of 5-10 min with microwave radiation power of 280, 560, 800 W, respectively. F- and t-tests confirmed that there were no significant differences between MWAH and conventional method. MWAH models between activated/physicochemical sludge concentrations (1000-12,000 mg/L), microwave radiation power as well as drying time were established. The relative errors were in the range of +/- 10% by applying these models. In addition, MWAH model based on 800 W of microwave radiation power was applied for rapid analysis of real wastewater sludge samples with different properties. Results demonstrated that sludge concentrations determined by MWAH method had high precision and could satisfy the analysis requirement of conventional method. Compared with conventional method, the microwave drying time and energy consumption by MWAH method can be reduced by 83.3% and 86.7%, respectively. Our study indicated that MWAH method was a rapid and low energy alternative to conventional method for sludge concentration determination in wastewater treatment systems

Double coating protection of Nd-Fe-B magnets: Intergranular phosphating treatment and copper plating

In this work, a double coating protection technique of phosphating treatment and copper plating was made to improve the corrosion resistance of sintered Nd-Fe-B magnets. In other words, the intergranular region of sintered Nd-Fe-B is allowed to generate passive phosphate conversion coating through phosphating treatment, followed by the copper coating on the surface of sintered Nd-Fe-B. The morphology and corrosion resistance of the phosphated sintered Nd-Fe-B were observed using SEM and electrochemical method respectively. The phosphate conversion coating was formed more preferably on the intergranular region of sintered Nd-Fe-B than on the main crystal region; just after a short time of phosphating treatment, the intergranular region of sintered Nd-Fe-B has been covered by the phosphate conversion coating and the corrosion resistance is significantly improved. With the synergistic protection of the intergranular phosphorization and the followed copper electrodeposition, the corrosion resistance of the sintered Nd-Fe-B is significantly better than that with a single phosphate film or single plating protection. (C) 2014 Elsevier B.V. All rights reserved

Comparative analysis on adsorption properties and mechanisms of nitrate and phosphate by modified corn stalks

In this study, modified corn stalks (MCS) were successfully synthesized by grafting or crosslinking triethylenetetramine (TETA) and triethylamine (TEA) in the presence of epichlorohydrin (EPI) and N,N-dimethylformamide (DMF) for the effective removal of nitrate and phosphate. The characteristics of adsorbents were determined and the adsorption properties and mechanisms of nitrate and phosphate on MCS were studied and compared. Results from Zeta potential, elemental analysis (EA), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) showed that quaternary ammonium group was successfully grafted onto corn stalks (CS). Both adsorption properties and mechanisms indicated that the MCS had a better affinity to phosphate. For adsorption properties, under conditions of a dosage of 4 g L-1, pH 6.0 and an initial concentration of 50 mg L-1, the phosphate removal rate was 10.97% higher than that nitrate, and SO42- and Cl- had a larger inhibitive effect on nitrate. Mechanisms analysis included adsorption kinetics, isotherm and thermodynamics. Results indicated that the parameters of different models were closely related to the adsorption effect of nitrate and phosphate. In addition, pseudo-second-order and Freundlich model fitted both nitrate and phosphate adsorption well. The thermodynamics analysis indicated that the adsorption process was spontaneous and endothermic in nature