The calculation and optimal allocation of transmission capacity in natural gas networks with MINLP models

The transmission capacity of gas pipeline networks should be calculated and allocated to deal with the capacity booking with shippers. Technical capacities, which depend on the gas flow distribution at routes or interchange points, are calculated with a multiobjective optimization model and form a Pareto solution set in the entry/exit or point-to-point regime. Then, the commercial capacities, which can be directly applied in capacity booking, are calculated with single-objective optimization models that are transformed from the above multiobjective model based on three allocation rules and the demand of shippers.Next, peak-shaving capacities, which are daily oversupply or overdelivery amounts at inlets or deliveries,are calculated with two-stage transient optimization models. Considering the hydraulic process of a pipeline network and operating schemes of compressor stations, all the above models are mixed-integer nonlinear programming problems. Finally, a case study is made to demonstrate the ability of the models.

Synthesis of Osthole Derivatives with Grignard Reagents and Their Larvicidal Activities on Mosquitoes

The structure of osthole has been modified to improve its larvicidal activity against mosquitoes. A new efficient synthesis of osthole derivatives with Grignard reagents has been developed, which employs CuI and LiCI as pro- moters and covers a broad range of substrates to afford the corresponding products in mild to good yields （up to 83%）. Bio-activity evaluation showed that several products exhibited better activities than osthole.

Numerical analysis of crack-tip fields of piezoelectric media by hybrid finite element

A hybrid model, piezoelectric P-S element, is developed for electro-elastic crack analysis. The model is used to investigate coupling crack-tip fields. The obtained numerical solutions recover the 1/r1/2 singularity, and it is in good consistence with the real ones. The results offer a valuable basis for studying the mechanism of coupling fracture.

A novel methodology for forecasting gas supply reliability of natural gas pipeline systems

In this paper,a novel systematic and integrated methodology to assess gas supply reliability is proposed based on the Monte Carlo method,statistical analysis,mathematical-probabilistic analysis,and hydraulic simulation.The method proposed has two stages.In the first stage,typical scenarios are determined.In the second stage,hydraulic simulation is conducted to calculate the flow rate in each typical scenario.The result of the gas pipeline system calculated is the average gas supply reliability in each typical scenario.To verify the feasibility,the method proposed is applied for a real natural gas pipelines network system.The comparison of the results calculated and the actual gas supply reliability based on the filed data in the evaluation period suggests the assessment results of the method proposed agree well with the filed data.Besides,the effect of different components on gas supply reliability is investigated,and the most critical component is identified.For example,the 48th unit is the most critical component for the SH terminal station,while the 119th typical scenario results in the most severe consequence which causes the loss of 175.61×10^4 m^3 gas when the 119th scenario happens.This paper provides a set of scientific and reasonable gas supply reliability indexes which can evaluate the gas supply reliability from two dimensions of quantity and time.

Design, Synthesis, and Insecticidal Activities of Novel Pyranoside Derivatives Targeting at Potential Second Calcium Channel IP3 Receptor

In order to search for potent and environmental friendly insecticides with new modes of action, a series of pyranoside derivatives mimicking D-myo-inositol 1,4,5-trisphosphate （IP3） were designed and synthesized according to the bioisosterie approach. The biological assay indicated that most of the new compounds showed moderate to good insecticidal activities against oriental armyworm （Mythimna separata） and diamondback moth （PluteIla xylostella）. Especially, compound 5g displayed 80% larvicidal activity against oriental armyworm at 50 mg/L. Meanwhile, 5a showed 100% and 70% larvicidal activities against diamondback moth at 50 and 25 nag/L, respectively. To further explore the mode of action, calcium imaging technique was applied to study the effects of 5a, 5g, and 5i on the intracellular calcium ion concentration （[Ca^2＋]i） in central neurons isolated from Spodoptera exigua. The results indicated that the tested compounds released stored calcium ions from endoplasmic reticulum.