Resilience-Oriented Load Restoration Method and Repair Strategies for Regional Integrated Electricity-Natural Gas System

The rising frequency of extreme disaster events seriously threatens the safe and secure operation of the regional integrated electricity-natural gas system(RIENGS).With the growing level of coupling between electric and natural gas systems,it is critical to enhance the load restoration capability of both systems.This paper proposes a coordinated optimization strategy for resilience-enhanced RIENGS load restoration and repair scheduling and transforms it into a mixed integer second-order cone programming(MISOCP)model.The proposed model considers the distribution network reconfiguration and the coordinated repair strategy between the two systems,minimizing the total system load loss cost and repair time.In addition,a bi-directional gas flow model is used to describe the natural gas system,which can provide the RIENGS with more flexibility for load restoration during natural gas system failure.Finally,the effectiveness of the proposed approach is verified by conducting case studies on the test systems RIENGS E13-G7 and RIENGS E123-G20.

Causality Diagram-based Scheduling Approach for Blast Furnace Gas System

Rational use of blast furnace gas(BFG) in steel industry can raise economic profit, save fossil energy resources and alleviate the environment pollution. In this paper, a causality diagram is established to describe the causal relationships among the decision objective and the variables of the scheduling process for the industrial system, based on which the total scheduling amount of the BFG system can be computed by using a causal fuzzy C-means(CFCM) clustering algorithm. In this algorithm,not only the distances among the historical samples but also the effects of different solutions on the gas tank level are considered.The scheduling solution can be determined based on the proposed causal probability of the causality diagram calculated by the total amount and the conditions of the adjustable units. The causal probability quantifies the impact of different allocation schemes of the total scheduling amount on the BFG system. An evaluation method is then proposed to evaluate the effectiveness of the scheduling solutions. The experiments by using the practical data coming from a steel plant in China indicate that the proposed approach can effectively improve the scheduling accuracy and reduce the gas diffusion.

A natural gas hydrate-oil-gas system in the Qilian Mountain permafrost area, northeast of Qinghai-Tibet Plateau

Natural gas hydrate,oil and gas were all found together in the Qilian Mountain permafrost area,northeast of Qinghai-Tibet Plateau,China.They are closely associated with each other in space,but whether they are in any genetic relations are unknown yet.In this paper,a hydrocarbon gas-generation series,gas-fluid migration series and hydrocarbon gas-accumulation series are analyzed to probe the spatial,temporal and genetic relationships among natural natural gas hydrate,oil and gas.The subsequent results show that natural gas hydrate,oil and gas actually form a natural gas hydrate-oil-gas system.Based on the Middle Jurassic and the Upper Triassic hydrocarbon gas-generation series,it is divided into four major sub-systems in the study area:(1)A conventional Upper Triassic gas-bearing sub-system with peak hydrocarbon gas-generation in the late Middle Jurassic;(2)a conventional Middle Jurassic oil-bearing sub-system with low to mature hydrocarbon gas-generation in the late Middle Jurassic;(3)a natural gas hydrate sub-system with main gas source from the Upper Triassic gas-bearing sub-system and minor gas source from the Middle Jurassic oil-bearing sub-system as well as little gas source from the Middle Jurassic coal-bed gas and the microbial gas;(4)a shallower gas sub-system with microbial alteration of the main gas source from the Upper Triassic gas-bearing sub-system.This natural gas hydrate-oil-gas system and its sub-systems are not only theoretical but also practical,and thus they will play an important role in the further exploration of natural gas hydrate,oil and gas,even other energy resources in the study area.

EQUATION OF STATE BASED HYDRATE MODEL FOR NATURAL GAS SYSTEMS CONTAINING BRINE AND POLAR INHIBITOR

1 INTRODUCTIONIn the past two decades,as large reserves of hydrocarbons were discovered in the formof natural gas hydrates stored in deep oceans and permafrost regions such reserves mayturn out to become a tremendous energy source in the future.Among the challengingproblems emerged from offshore oil/gas exploration and production,hydrate research re-ceived new impetus.

Parametric study of the clustering transition in vibration driven granular gas system

A parametric study of the clustering transition of a vibration-driven granular gas system is performed by simulation.The parameters studied include the global volume fraction of the system,the size of the system,the friction coefficient,and the restitution coefficient among particles and among particle-walls.The periodic boundary and fixed boundary of sidewalls are also checked in the simulation.The simulation results provide us the necessary“heating”time for the system to reach steady state,and the friction term needed to be included in the“cooling”time.A gas-cluster phase diagram obtained through Kolmogorov-Smirnov(K-S)test analysis using similar experimental parameters is given.The influence of the parameters to the transition is then investigated in simulations.This simulation investigation helps us gain understanding which otherwise cannot be obtained by experiment alone,and makes suggestions on the determination of parameters to be chosen in experiments.

Oxygen Potentials and Oxygen-potential Diagrams for Buffer Gas System at Normal Pressure

The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ly a particular representation under ignoring the effects of oxygen,thereby being unavailable for accurate cal- culation of oxygen potentials.In this paper,the oxygen potentials set by CO_2-H_2 gas mixtures and the mis- takes and errors of the classical expressions for them were discussed emphatically.The deviation in partial pressures of oxygen in some of previous experiments under the oxygen potentials controlled by CO_2-H_2 gas mixtures was explained quantitatively.The oxygen-potential diagrams predicting the equilibrated gas com- positions from the initial conditions have been also given.

Real-time Risk-averse Dispatch of an Integrated Electricity and Natural Gas System via Condi-tional Value-at-risk-based Lookup-table Ap-proximate Dynamic Programming

The real-time risk-averse dispatch problem of an integrated electricity and natural gas system(IEGS)is studied in this paper.It is formulated as a real-time conditional value-at-risk(CVaR)-based risk-averse dis-patch model in the Markov decision process framework.Because of its stochasticity,nonconvexity and nonlinearity,the model is difficult to analyze by traditional algorithms in an acceptable time.To address this non-deterministic polynomial-hard problem,a CVaR-based lookup-table approximate dynamic programming(CVaR-ADP)algo-rithm is proposed,and the risk-averse dispatch problem is decoupled into a series of tractable subproblems.The line pack is used as the state variable to describe the impact of one period’s decision on the future.This facilitates the reduction of load shedding and wind power curtailment.Through the proposed method,real-time decisions can be made according to the current information,while the value functions can be used to overview the whole opti-mization horizon to balance the current cost and future risk loss.Numerical simulations indicate that the pro-posed method can effectively measure and control the risk costs in extreme scenarios.Moreover,the decisions can be made within 10 s,which meets the requirement of the real-time dispatch of an IEGS.Index Terms—Integrated electricity and natural gas system,approximate dynamic programming,real-time dispatch,risk-averse,conditional value-at-risk.

Deep-large faults controlling on the distribution of the venting gas hydrate system in the middle of the Qiongdongnan Basin, South China Sea

Many locations with concentrated hydrates at vents have confirmed the presence of abundant thermogenic gas in the middle of the Qiongdongnan Basin(QDNB).However,the impact of deep structures on gasbearing fluids migration and gas hydrates distribution in tectonically inactive regions is still unclear.In this study,the authors apply high-resolution 3D seismic and logging while drilling(LWD)data from the middle of the QDNB to investigate the influence of deep-large faults on gas chimneys and preferred gasescape pipes.The findings reveal the following:(1)Two significant deep-large faults,F1 and F2,developed on the edge of the Songnan Low Uplift,control the dominant migration of thermogenic hydrocarbons and determine the initial locations of gas chimneys.(2)The formation of gas chimneys is likely related to fault activation and reactivation.Gas chimney 1 is primarily arises from convergent fluid migration resulting from the intersection of the two faults,while the gas chimney 2 benefits from a steeper fault plane and shorter migration distance of fault F2.(3)Most gas-escape pipes are situated near the apex of the two faults.Their reactivations facilitate free gas flow into the GHSZ and contribute to the formation of fracture‐filling hydrates.

Development of a 2D spatial displacement estimation method for turbulence velocimetry of the gas puff imaging system on EAST

A gas puff imaging(GPI)diagnostic has been developed and operated on EAST since 2012,and the time-delay estimation(TDE)method is used to derive the propagation velocity of fluctuations from the two-dimensional GPI data.However,with the TDE method it is difficult to analyze the data with fast transient events,such as edge-localized mode(ELM).Consequently,a method called the spatial displacement estimation(SDE)algorithm is developed to estimate the turbulence velocity with high temporal resolution.Based on the SDE algorithm,we make some improvements,including an adaptive median filter and super-resolution technology.After the development of the algorithm,a straight-line movement and a curved-line movement are used to test the accuracy of the algorithm,and the calculated speed agrees well with preset speed.This SDE algorithm is applied to the EAST GPI data analysis,and the derived propagation velocity of turbulence is consistent with that from the TDE method,but with much higher temporal resolution.

Microplastic Impacts on Greenhouse Gases Emissions in Terrestrial Ecosystems

Microplastics can influence global climate change by regulating the emissions of greenhouse gases from different ecosystems. The effects of microplastics in terrestrial ecosystems are still not well studied particularly greenhouse gases emissions. Thus, we conducted a laboratory experiment over a period of 90 days with two types of microplastics (differing in their chemical structure), high density polyethylene (HDPE) and low density polyethylene (LDPE), which were applied to the soil at a rate of 0% to 0.1% (w/w). The overarching aim was to investigate the effects of microplastic type, microplastic concentration and days of exposure on greenhouse gases emissions. We also used original and artificially weathered microplastics (the same HDPE and LDPE) to make a comparison of greenhouse gases emissions between the original microplastics treated soils and the soils treated with weathered microplastics. Our findings showed that HDPE and LDPE microplastics significantly increased the emissions of greenhouse gases from the soil than that of the control soils. Emissions were increased with the increases in the level of microplastic in the soil. The weathered microplastic emitted greater quantity of greenhouse gases compared to that of the original microplastics. In contrast to a low initial emission quantity, the emissions were gradually increased at the termination of the experiment. Our experiment on the emissions of greenhouse gases from the soil vis-à-vis microplastic additions indicated that the microplastic increased the emissions of greenhouse gases in terrestrial ecosystems, and pervasive microplastic impacts may have consequences for the global climate change. Greenhouse gases emissions from the soil not only depend on the type and concentration of the microplastic, but also on the days of exposure to the microplastic.

Optimization of the Gas Generator in Composite Power System with Tip-Jet Rotor

The key and bottleneck of research on the tip-jet rotor compound helicopter lies in the power system. Computational Fluid Dynamics (CFD) was used to numerically simulate the gas generator and rotor inner passage of the tip-jet rotor composite power system, studying the effects of intake mode, inner cavity structure, propellant components, and injection amount on the characteristics of the composite power system. The results show that when a single high-temperature exhaust gas enters, the gas generator outlet fluid is uneven and asymmetric;when two-way high-temperature exhaust gas enters, the outlet temperature of the gas generator with a tilted inlet is more uniform than that with a vertical inlet;adding an inner cavity improves the temperature and velocity distribution of the gas generator's internal flow field;increasing the energy of the propellant is beneficial for improving the available moment.

Whole petroleum system and ordered distribution pattern of conventional and unconventional oil and gas reservoirs

The classical source-to-trap petroleum system concept only considers the migration and accumulation of conventional oil and gas in traps driven dominantly by buoyance in a basin,although revised and improved,even some new concepts as composite petroleum system,total petroleum system,total composite petroleum system,were proposed,but they do not account for the vast unconventional oil and gas reservoirs within the system,which is not formed and distributed in traps dominantly by buoyancedriven.Therefore,the petroleum system concept is no longer adequate in dealing with all the oil and gas accumulations in a basin where significant amount of the unconventional oil and gas resources are present in addition to the conventional oil and gas accumulations.This paper looked into and analyzed the distribution characteristics of conventional and unconventional oil/gas reservoirs and their differences and correlations in petroliferous basins in China and North America,and then proposed whole petroleum system(WPS)concept,the WPS is defined as a natural system that encompasses all the conventional and unconventional oil and gas,reservoirs and resources originated from organic matter in source rocks,the geological elements and processes involving the formation,evolution,and distribution of these oil and gas,reservoirs and resources.It is found in the WPS that there are three kinds of hydrocarbons dynamic fields,three kinds of original hydrocarbons,three kinds of reservoir rocks,and the coupling of these three essential elements lead to the basic ordered distribution model of shale oil/gas reservoirs contacting or interbeded with tight oil/gas reservoirs and separated conventional oil/gas reservoirs from source rocks upward,which is expressed as“S\T-C”.Abnormal conditions lead to other three special ordered distribution models:The first is that with shale oil/gas reservoirs separated from tight oil/gas reservoirs.The second is that with two direction ordered distributions from source upward and downward.The third is with lateral distribution from source outside.

Upper Paleozoic total petroleum system and geological model of natural gas enrichment in Ordos Basin, NW China

Based on the analysis of Upper Paleozoic source rocks, source-reservoir-caprock assemblage, and gas accumulation characteristics in the Ordos Basin, the gas accumulation geological model of total petroleum system is determined. Then, taking the Carboniferous Benxi Formation and the Permian Taiyuan Formation and Shanxi Formation as examples, the main controlling factors of gas accumulation and enrichment are discussed, and the gas enrichment models of total petroleum system are established. The results show that the source rocks, faults and tight reservoirs and their mutual coupling relations control the distribution and enrichment of gas. Specifically, the distribution and hydrocarbon generation capacity of source rocks control the enrichment degree and distribution range of retained shale gas and tight gas in the source. The coupling between the hydrocarbon generation capacity of source rocks and the physical properties of tight reservoirs controls the distribution and sweet spot development of near-source tight gas in the basin center. The far-source tight gas in the basin margin is mainly controlled by the distribution of faults, and the distribution of inner-source, near-source and far-source gas is adjusted and reformed by faults. Generally, the Upper Paleozoic gas in the Ordos Basin is recognized in four enrichment models: inner-source coalbed gas and shale gas, inner-source tight sandstone gas, near-source tight gas, and far-source fault-transported gas. In the Ordos Basin, inner-source tight gas and near-source tight gas are the current focuses of exploration, and inner-source coalbed gas and shale gas and far-source gas will be important potential targets in the future.

Multiobjective economic model predictive control using utopia-tracking for the wet flue gas desulphurization system

Efficient control of the desulphurization system is challenging in maximizing the economic objective while reducing the SO_(2) emission concentration. The conventional optimization method is generally based on a hierarchical structure in which the upper optimization layer calculates the steady-state results and the lower control layer is responsible to drive the process to the target point. However, the conventional hierarchical structure does not take the economic performance of the dynamic tracking process into account. To this end, multi-objective economic model predictive control(MOEMPC) is introduced in this paper, which unifies the optimization and control layers in a single stage. The objective functions are formulated in terms of a dynamic horizon and to balance the stability and economic performance. In the MOEMPC scheme, economic performance and SO_(2) emission performance are guaranteed by tracking a set of utopia points during dynamic transitions. The terminal penalty function and stabilizing constraint conditions are designed to ensure the stability of the system. Finally, an optimized control method for the stable operation of the complex desulfurization system has been established. Simulation results demonstrate that MOEMPC is superior over another control strategy in terms of economic performance and emission reduction, especially when the desulphurization system suffers from frequent flue gas disturbances.

Neutronics analysis of a subcritical blanket system driven by a gas dynamic trap-based fusion neutron source for ^(99)Mo production

Gamma-emitting radionuclide ^(99m)Tc is globally used for the diagnosis of various pathological conditions owing to its ideal single-photon emission computed tomography (SPECT) characteristics.However,the short half-life of ^(99m)Tc (T_(1/2)=6 h)makes it difficult to store or transport.Thus,the production of ^(99m)Tc is tied to its parent radionuclide ^(99)Mo (T_(1/2)=66 h).The major production paths are based on accelerators and research reactors.The reactor process presents the potential for nuclear proliferation owing to its use of highly enriched uranium (HEU).Accelerator-based methods tend to use deuterium–tritium(D–T) neutron sources but are hindered by the high cost of tritium and its challenging operation.In this study,a new ^(99)Mo production design was developed based on a deuterium–deuterium (D–D) gas dynamic trap fusion neutron source (GDT-FNS) and a subcritical blanket system (SBS) assembly with a low-enriched uranium (LEU) solution.GDT-FNS can provide a relatively high-neutron intensity,which is one of the advantages of ^(99)Mo production.We provide a Monte Carlo-based neutronics analysis covering the calculation of the subcritical multiplication factor (k_(s)) of the SBS,optimization design for the reflector,shielding layer,and ^(99)Mo production capacity.Other calculations,including the neutron flux and nuclear heating distributions,are also provided for an overall evaluation of the production system.The results demonstrated that the SBS meets the nuclear critical safety design requirement (k_(s)<0.97) and maintained a high ^(99)Mo production capacity.The proposed system can generate approximately 157 Ci ^(99)Mo for a stable 24 h operation with a neutron intensity of 1×10^(14) n/s,which can meet 50%of China’s demand in 2025.

基于GAS算法的卵砾石粒径自动识别应用研究

粒径和级配是表征床面组成的重要指标,基于GAS粒径自动识别技术可自动识别粗粒床面粒径并生成级配曲线,能够大幅提高现场采样和分析的效率。为了验证GAS的分割效果,采用GAS提供的默认参数进行分割,同时应用ImageJ软件手动分割进行验证。结果表明:GAS级配曲线的相对误差为5.7%,相关系数为0.992。另外,采用单参数和多参数敏感性分析法来标准化参数调整方案,gre、can1和can2对GAS提取的级配曲线和特征粒径有显著影响,其中gre起主导作用,而can1和can2控制着砾石边界的检测完整性。

GAS6-AS1调节miR-370-3p/SPATA2轴对卵巢癌细胞增殖、迁移、侵袭、凋亡和EMT的影响

目的:探讨长链非编码RNA GAS6反义RNA1(long non-coding RNA GAS6 antisense RNA1, lncRNA GAS6-AS1)调节miR-370-3p/精子发生相关蛋白2 (spermatogenesis-associated protein 2, SPATA2)轴对卵巢癌细胞增殖、迁移、侵袭、凋亡和上皮间质转化(epithelial mesenchymal transformation, EMT)的影响。方法:qRT-PCR、Western blot分别检测癌旁组织、卵巢癌组织、人正常卵巢上皮细胞IOSE80及卵巢癌细胞系HO-8910、SKOV3、A2780中GAS6-AS1、miR-370-3p及SPATA2蛋白表达。将SKOV3细胞分为:对照组(NC组)、 si-NC组、si-GAS6-AS1组、mimic NC组、miR-370-3p mimic组、si-GAS6-AS1+inhibitor NC组、si-GAS6-AS1+miR-370-3p inhibitor组,qRT-PCR检测细胞中GAS6-AS1、miR-370-3p表达;CCK-8法检测细胞增殖;流式细胞术检测细胞凋亡;划痕愈合实验检测细胞迁移;Transwell实验检测细胞侵袭;Western blot检测SPATA2、细胞周期素D1(CyclinD1)、Bcl-2相关X蛋白(Bcl-2-associated X,Bax)、E-钙黏蛋白(E-cadherin)、波形蛋白(Vimentin)、神经钙黏蛋白(N-cadherin)表达;双荧光素酶报告基因实验检测GAS6-AS1与miR-370-3p、 miR-370-3p与SPATA2的关系。结果:在卵巢癌组织和细胞中GAS6-AS1、SPATA2蛋白高表达,miR-370-3p低表达,且在SKOV3细胞中GAS6-AS1、SPATA2蛋白表达量最高,miR-370-3p表达水平最低,因此,选择SKOV3细胞为后续研究对象。与NC组、si-NC组比较,si-GAS6-AS1组GAS6-AS1、OD450值(24 h、48 h、72 h)、划痕愈合率、侵袭细胞数、SPATA2、CyclinD1、Vimentin、N-cadherin蛋白表达降低,miR-370-3p表达、细胞凋亡率、Bax、E-cadherin蛋白表达升高(P<0.05);与NC组、mimic NC组比较,miR-370-3p mimic组OD450值(24 h、48 h、72 h)、划痕愈合率、侵袭细胞数、SPATA2、CyclinD1、Vimentin、N-cadherin蛋白表达降低,miR-370-3p表达、细胞凋亡率、Bax、E-cadherin蛋白表达升高(P<0.05);miR-370-3p inhibitor减弱了沉默GAS6-AS1对SKOV3细胞增殖、迁移、侵袭及EMT的抑制及对细胞凋亡的促进作用。GAS6-AS1与miR-370-3p、miR-370-3p与SPATA2存在靶向调控关系。结论:沉默GAS6-AS1通过上调miR-370-3p来抑制SPATA2表达,从而抑制SKOV3细胞增殖、迁移、侵袭及EMT,并促进细胞凋亡。

Repositioning fertilizer manufacturing subsidies for improving food security and reducing greenhouse gas emissions in China

China removed fertilizer manufacturing subsidies from 2015 to 2018 to bolster market-oriented reforms and foster environmentally sustainable practices.However,the impact of this policy reform on food security and the environment remains inadequately evaluated.Moreover,although green and low-carbon technologies offer environmental advantages,their widespread adoption is hindered by prohibitively high costs.This study analyzes the impact of removing fertilizer manufacturing subsidies and explores the potential feasibility of redirecting fertilizer manufacturing subsidies to invest in the diffusion of these technologies.Utilizing the China Agricultural University Agri-food Systems model,we analyzed the potential for achieving mutually beneficial outcomes regarding food security and environmental sustainability.The findings indicate that removing fertilizer manufacturing subsidies has reduced greenhouse gas(GHG)emissions from agricultural activities by 3.88 million metric tons,with minimal impact on food production.Redirecting fertilizer manufacturing subsidies to invest in green and low-carbon technologies,including slow and controlled-release fertilizer,organic-inorganic compound fertilizers,and machine deep placement of fertilizer,emerges as a strategy to concurrently curtail GHG emissions,ensure food security,and secure robust economic returns.Finally,we propose a comprehensive set of government interventions,including subsidies,field guidance,and improved extension systems,to promote the widespread adoption of these technologies.

Elimination mechanism of coal and gas outburst based on geo‑dynamic system with stress–damage–seepage interactions

Coal and gas outburst is a complex dynamic disaster during coal underground mining.Revealing the disaster mechanism is of great signifcance for accurate prediction and prevention of coal and gas outburst.The geo-dynamic system of coal and gas outburst is proposed.The framework of geo-dynamic system is composed of gassy coal mass,geological dynamic environment and mining disturbance.Equations of stress–damage–seepage interaction for gassy coal mass is constructed to resolve the outburst elimination process by gas extraction with boreholes through layer in foor roadway.The results show the occurrence of outburst is divided into the evolution process of gestation,formation,development and termination of geo-dynamic system.The scale range of outburst occurrence is determined,which provides a spatial basis for the prevention and control of outburst.The formation criterion and instability criterion of coal and gas outburst are established.The formation criterion F1 is defned as the scale of the geo-dynamic system,and the instability criterion F2 is defned as the scale of the outburst geo-body.According to the geo-dynamic system,the elimination mechanism of coal and gas outburst—‘unloading+depressurization’is established,and the gas extraction by boreholes through layer in foor roadway for outburst elimination is given.For the research case,when the gas extraction is 120 days,the gas pressure of the coal seam is reduced to below 0.4 MPa,and the outburst danger is eliminated efectively.

THE EXISTENCE OF GLOBAL SOLUTIONS FOR THE FULL NAVIER-STOKES-KORTEWEG SYSTEM OF VAN DER WAALS GAS

The aim of this work is to prove the existence for the global solution of a nonisothermal or non-isentropic model of capillary compressible fluids derived by J.E.Dunn and J.Serrin(1985),in the case of van der Waals gas.Under the small initial perturbation,the proof of the global existence is based on an elementary energy method using the continuation argument of local solution.Moreover,the uniqueness of global solutions and large time behavior of the density are given.It is one of the main difficulties that the pressure p is not the increasing function of the densityρ.