Research on the Recovery of Irregular Flights under Uncertain Conditions

This paper mainly studies the problem of irregular flights recovery under uncertain conditions. Based on the analysis of the uncertain factors affecting the flight, taking the total delay time and the total cost of flight delay as the objective function, and considering the constraints of flight plan and passenger journey, an uncertain objective programming model is constructed. Finally, taking OVS airport temporarily closed due to bad weather as an example, the results show that better quality optimization scheme can be obtained by integrating passenger recovery with narrow sense flight recovery stage and implementing integrated recovery.

Enhanced Atom Search Optimization Based Optimal Control Parameter Tunning of PMSG for MPPT

For the past few years,wind energy is the most popular non-traditional resource among renewable energy resources and it’s significant to make full use of wind energy to realize a high level of generating power.Moreover,diverse maximum power point tracking(MPPT)methods have been designed for varying speed operation of wind energy conversion system(WECS)applications to obtain optimal power extraction.Hence,a novel and metaheuristic technique,named enhanced atom search optimization(EASO),is designed for a permanent magnet synchronous generator(PMSG)based WECS,which can be employed to track the maximum power point.One of the most promising benefits of this technique is powerful global search capability that leads to fast response and high-quality optimal solution.Besides,in contrast with other conventional meta-heuristic techniques,EASO is extremely not relying on the original solution,which can avoid sinking into a low-quality local maximum power point(LMPP)by realizing an appropriate trade-off between global exploration and local exploitation.At last,simulations employing two case studies through Matlab/Simulink validate the practicability and effectiveness of the proposed techniques for optimal proportional-integral-derivative(PID)control parameters tuning of PMSG based WECS under a variety of wind conditions.

输电线路发生单相接地短路后采样周期对测距精度的影响

本文分析了输电线路三相系统发生单相接地短路故障时工频测距的基本原理。选用PSCAD/EMTDC仿真软件搭建输电线路分布参数模型,针对输电线路发生单相接地短路故障进行仿真,使用傅立叶算法对故障周期进行提取并计算电压电流工频量,利用基于工频分量的单端故障测距原理进行故障测距。分析利用傅立叶算法在提取电压电流工频量时选取不同采样周期对测距精度的影响。借助福建霞浦小沙110 KV大京风电线发生单相接地短路故障时,录波器采集到的实时故障数据,验证采样周期对测距结果的影响。对利用工频量进行故障测距时采样周期的选取有一定的借鉴意义。

Toward atomistic models of intact severe acute respiratory syndrome coronavirus 2 via Martini coarsegrained molecular dynamics simulations

The causative pathogen of coronavirus disease 2019(COVID-19),severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),is an enveloped virus assembled by a lipid envelope and multiple structural proteins.In this study,by integrating experimental data,structural modeling,as well as coarse-grained and all-atom molecular dynamics simulations,we constructed multiscale models of SARS-CoV-2.Our 500-ns coarse-grained simulation of the intact virion allowed us to investigate the dynamic behavior of the membrane-embedded proteins and the surrounding lipid molecules in situ.Our results indicated that the membrane-embedded proteins are highly dynamic,and certain types of lipids exhibit various binding preferences to specific sites of the membrane-embedded proteins.The equilibrated virion model was transformed into atomic resolution,which provided a 3D structure for scientific demonstration and can serve as a framework forfuture exascale allatom molecular dynamics(MD)simulations.A short all-atom molecular dynamics simulation of 255 ps was conducted as a preliminary test for largescale simulationsofthis complexsystem.

mSwap: a large-scale image-compositing method with optimal m-ary tree

With the increasing of computing ability,large-scale simulations have been generating massive amounts of data in aerodynamics.Sort-last parallel rendering is the most classical image compositing method for large-scale scientific visualization.However,in the stage of image compositing,the sort-last method may suffer from scalability problem on large-scale processors.Existing image compositing algorithms tend to perform well in certain situations.For instance,Direct Send is well on small and medium scale;Radix-k gets well performance only when the k-value is appropriate and so on.In this paper,we propose a novel method named mSwap for scientific visualization in aerodynamics,which uses the best scale of processors to make sure its performance at the best.mSwap groups the processors that we can use with a(m,k)table,which records the best combination of m(the number of processors in subgroup of each group)and k(the number of processors in each group).Then in each group,using a m-ary tree to composite the image for reducing the communication of processors.Finally,the image is composited between different groups to generate the final image.The performance and scalability of our mSwap method is demonstrated through experiments with thousands of processors.

In-situ sampling investigation of deposition and corrosion of convective heating surfaces in a grate type municipal solid waste incineration plant:a case study

Metal corrosion and ash deposition are two common issues in municipal solid waste incineration(MSWI)plants.An in-situ sampling investigation was conducted in an MSWI plant in Jiangsu,China.The deposit samples were collected from 6 convective heating surfaces including the reheaters,superheaters,and economizer.The corrosion samples were obtained from a ruptured tube cut from the tertiary superheater.The element composition,crystal phases,and morphology of deposit and corrosion samples were characterized and analyzed.The results show that S contents of these deposits are 32-45 wt%,considerable Cl(10.63 wt%)was only detected in the deposits of the tertiary superheater.The composition of the deposits varies with the location because the flue gas temperature determines the thermodynamic trend of the sulfation reactions of different chlorides and the SO_(2)equilibrium partial pressure required in these reactions.Ca sulfates mainly exist in deposits at high temperatures(above approximately 500℃).Whereas alkali metal sulfates are the main component of deposits at low temperatures(below approximately 500℃).A multi-layer structure is exhibited on the cross-section of the corrosion samples.The discovery of Cl in the interface between the matrix and the oxide layer confirms that Cl can penetrate the outer oxide film.Besides,polysulfate components were observed inside the metal oxide layers,which indicates that a melt has occurred there.This study has provided a better understanding of ash deposition and corrosion phenomena in MSWI systems and more emphasis should be placed on the research of ash deposition and corrosion mechanisms.