Characterization of particulate products for aging of ethylbenzene secondary organic aerosol in the presence of ammonium sulfate seed aerosol

Aging of secondary organic aerosol(SOA) particles formed from OH– initiated oxidation of ethylbenzene in the presence of high mass(100–300 μg/m~3) concentrations of(NH_4)_2SO_4seed aerosol was investigated in a home-made smog chamber in this study.The chemical composition of aged ethylbenzene SOA particles was measured using an aerosol laser time-of-flight mass spectrometer(ALTOFMS) coupled with a Fuzzy C-Means(FCM) clustering algorithm.Experimental results showed that nitrophenol,ethyl-nitrophenol,2,4-dinitrophenol,methyl glyoxylic acid,5-ethyl-6-oxo-2,4-hexadienoic acid,2-ethyl-2,4-hexadiendioic acid,2,3-dihydroxy-5-ethyl-6-oxo-4-hexenoic acid,1H-imidazole,hydrated N-glyoxal substituted1H-imidazole,hydrated glyoxal dimer substituted imidazole,1H-imidazole-2-carbaldehyde,N-glyoxal substituted hydrated 1H-imidazole-2-carbaldehyde and high-molecular-weight(HMW) components were the predominant products in the aged particles.Compared to the previous aromatic SOA aging studies,imidazole compounds,which can absorb solar radiation effectively,were newly detected in aged ethylbenzene SOA in the presence of high concentrations of(NH_4)_2SO_4seed aerosol.These findings provide new information for discussing aromatic SOA aging mechanisms.     

支持向量机在边坡稳定性预测中的应用

针对离子型稀土原地浸矿边坡稳定性问题的小样本、非线性等特点,采用一种边坡稳定性预测模型——支持向量机(SVM)模型,分别使用网格参数寻优、遗传算法(GA)参数寻优、粒子群(PSO)寻优算法来计算SVM模型的参数,分析比较3种算法得到的参数,确定最适合离子型稀土原地浸矿边坡稳定性预测的SVM回归模型的参数寻优算法。     

惯性器件加速试验环境谱编制与数据处理方法研究

目的研究模拟惯性器件贮存环境温度变化的加速环境谱与加速试验方法。方法监测样品贮存环境温度应力变化的同时,检测样品性能的变化,通过雨流计数法将温度变化曲线转化为温度环境谱后再转换为加速环境谱,依照加速环境谱开展试验,通过试验结果与自然贮存样品性能比对,开展试验样品性能评价。结果以2012年某试验库房的温度数据为例,通过转换得到了模拟惯性器件贮存环境的环境谱和加速环境谱,并得到了用于指导惯性器件加速试验的方法。结论将雨流计数法用于处理惯性器件经历的温度曲线,转化得到的加速试验方法,可以较好地模拟惯性器件贮存实际经历的温度变化过程,指导对惯性器件的性能变化趋势进行预测和评价。     

An optimization of artificial neural network modeling methodology for the reliability assessment of corroding natural gas pipelines

A fast calculation of the reliability is meaningful to the in-line inspection of corroding natural gas pipelines. However, the traditional Monte Carlo simulation(MCS) method is time consuming for the low possibilities of the pipeline failure. The artificial neural network(ANN) is preferable for the complex nonlinear situation. An optimization of artificial neural network modeling methodology for the reliability assessment of corroding natural gas pipelines is proposed in this paper. To reduce the influence of training sets random behaviors on the calculation results, some algorithms are used to optimize the sequence of the training samples and the initial parameters of ANN models. The optimized model is applied to the reliability assessment of a corroded pipe with two successive inline inspections. According to the physical parameters of the pipeline, the trend of corroding pipeline reliability in time is predicted. The comparison between the trained ANN model, the MCS method and non-optimized ANN model shows the advantages the proposed modeling process. The methodology given in this paper is general and it can be applied to evaluate the reliability of other kind of structure safeties in practical systems.     

疏散路径受阻情况下的人员疏散模型及算法

建筑火灾中,随着火势的不断增大和烟气的不断增多,随时会有某条疏散路径因被火势或烟气封堵而不能正常通行的情况发生。针对此情况下的应急疏散问题,以待疏散人员全部完成疏散所需时间最短为目标,以结合疏散路径的通行能力合理分配待疏散人员为原则,运用Dijkstra算法对网络中的最短路径进行求解,并结合网络流控制的方法实现疏散人员的合理分配,建立了疏散路径受阻情况下的人员疏散模型,并提出了该模型的算法思想及算法步骤,最后结合算例进行了验证。验证结果表明,该模型及算法可行、有效,既可较好地避免因大量人员选择相同疏散路线而造成的拥堵,还提高了疏散网络的整体使用率,又有效缩短了人员的疏散所需时间。     

基于网络流理论的矿井通风网络可靠性研究

矿井通风网络是通风系统的重要组成部分,对其进行可靠性研究具有非常重要的意义。针对矿井通风网络系统的自身属性,结合网络流理论建立了通风网络可靠性评价模型。对各风路的风量进行动态实时监测,并运用统计学方法分析了风网中风流的变化趋势及风量分布规律,得到了通风系统中任一风路风量的分布密度函数,进而推导出各风路的可靠性指标值。运用简化的邻接终点矩阵法求解通风网络最小路集并基于MATLAB编程实现此算法。提出了一种简化的不交化最小路集算法:对于任一长度为m-1的最小路,只需在其中添加n-m+1条该最小路中不出现的分支的逆,就可直接获得不交化结果,其余最小路采用BDD算法进行不交化运算。通过以上方法可量化分析通风网络的可靠性。最后通过实例解算检验其可行性。     

A novel framework-based cuckoo search algorithm for sizing and optimization of grid-independent hybrid renewable energy systems

Hybrid renewable energy systems (HRES) turned into an appealing choice for supplying loads in remote areas. The application of smart grid principals in HRES provides a communication between the load and generation from the HRES. Using smart grid in the HRES will optimally utilize the generating resources to reschedule the loads depending on its importance. This paper presents a new proposed design and optimization simulation program for techno-economic sizing of grid-independent hybrid PV/wind/diesel/battery energy system using Cuckoo search (CS) optimization algorithm. Using of CS will help to get the global minimum cost condition and prevent the simulation to be stuck around local minimum. A new proposed simulation program (NPSP) is acquainted using CS to determine the optimum size of each component of the HRES for the lowest cost of generated energy and the lowest value of dummy energy, at highest reliability. A detailed economic methodology to obtain the price of the generated energy has been introduced. Results showed that using CS reduced the time required to obtain the optimal size with higher accuracy than other techniques used iterative techniques, Genetic Algorithm (GA), and Particle Swarm Optimization (PSO). Numerous significant outcomes can be extracted from the proposed program that could help scientists and decision makers.     

联合采用Inglada算法和Geiger算法确定地震精确位置

Inglada定位算法具有全局反演地震位置的优点,但只能采用均匀地壳结构求解地震位置,Geiger定位算法能够采用不均匀地壳结构进行定位,但给定的真解必须在实际解附近才能得到全局最优的震源位置。本研究结合Inglada和Geiger算法的各自优点,提出了地震定位算法的策略,即先采用Inglada算法得到接近真解的初始震源位置,然后采用Geiger算法对Inglada算法得到的解进行修改,以便得到考虑不均匀速度模型的震源位置。数值试验表明这种策略可以很好地约束地震的位置。我们将该算法应用于2008年2月11日江西瑞金ML2.3地震,得到了残差更小的地震精确位置。     

海上溢油事故双目标应急物资调度模型

为满足海上溢油事故发生后的应急物资需求,最大程度减少事故带来的损失,根据海上溢油应急物资调度的特点,构建基于应急物资需求量和调度时间模糊不确定下应急成本最小和延误时间最少的双目标调度模型。引入三角模糊函数描述应急物资调度中物资需求量和调度时间的不确定性,构建模糊环境下溢油事故点对应急物资应急成本最小和应急延误时间最少的双目标模型,利用遗传算法求解,并通过算例分析证明了该方法的有效性。结果表明,三角模糊数能很好地表征调度中物资需求量和时间的不确定性及模糊属性,确定的调度方案能为海上溢油事故发生时应急物资调度提供决策依据。     

基于弹塑性损伤-渗流耦合模型的隧道洞口段围岩稳定性研究

为分析复杂条件下隧道洞口段稳定性问题,建立基于Mohr-Coulomb准则的岩石弹塑性损伤-渗流耦合模型,利用完全隐式的向后欧拉算法编制弹塑性损伤模型的应力积分程序。在此基础上,利用ABAQUS平台的子程序接口实现耦合模型的有限元计算。将该模型应用于福建某洞口段隧道工程的围岩稳定性评价中,分析不同降雨强度下洞口段结构的安全系数、位移及损伤值的变化规律。结果表明:隧道洞口段结构的安全系数、损伤区和位移均会随着降雨进程的发展发生变化,雨季应加强监测频率。