基于网格空间数据的晋陕蒙接壤区生态环境综合评价

晋陕蒙接壤区是典型的生态过渡带、生态脆弱带。文章在调查研究的基础上 ,选取了 1 3个评价指标 ,应用层次分析法确定其权重 ,并将各个因子分级标准化和定量赋值 ,再用加权求和法得到每个评价单元的环境质量综合评价指数。根据环境综合评价指数将环境质量分为较好 (≥ 8)、一般 (≥ 6～ <8)、较差 (≥ 4～ <6)、恶劣 (<4) 4级。结果表明 :晋陕蒙接壤区的环境质量大多处于较差等级 ,较好、一般、较差、恶劣等级的面积比例分别为 2 .2 % ,2 8% ,5 7.4%和1 2 .4%     

平衡调温调湿方式中变流量冷冻水系统设计

通过对变流量冷冻水系统的分析指出，在运用平衡调温调湿方式的空调系统中，应用变流量冷冻水系统可以较大地节约能源和投资；并提出了实现这种应用的方法。     

城市地区毒气扩散事故数值模拟

在城市人口密集区域，一旦发生重大危险气体泄露事故，周围居民将处境危险。由于城市特殊的街道街谷影响，用普通的方法难以精确计算出场的时空分布，大涡模拟（Large Eddy Simulation）虽然较为精确，但对计算机计算能力要求较高。针对于此，可以通过一些方法，例如贴体网格分析、卫星遥感技术，局部网格加密技术，改进大涡模型的计算条件，考虑泄漏事故一旦发生时，道路、房屋、气候对于气体扩散的影响，对事故的致灾机理从动力学的角度进行研究。在箅例中，通过分析城市地区庙会时的一起事故．模拟气体扩散浓度的时空分布，得出城市地区各个地区的不同受灾程度。通过算例我们看到，数值模拟能够为进一步安全规划、灾害预防、应急反应提供决策支持．     

涡流澄清池与网格澄清池处理的对比试验研究

针对传统水力循环澄清池运行中所遇到的混凝效率低、出水水质差、抗冲击负荷能力弱等瓶颈问题,该试验通过对涡流澄清池与网格澄清池的启动、除浊效果、产水能力、抗冲击负荷能力进行平行对比试验,研究了涡流澄清池实际运行效果,确定了涡流澄清池的最佳运行工况及相关设计参数,为微涡流澄清技术在水厂改造、净水装置研发及其他工程应用提供设计参数支持和推广应用依据。     

不同喷雾方式下低阻文丘里振弦栅除尘配置优化实验研究

为了对比径向外喷和轴向喷雾下的低阻文丘里振弦栅耦合除尘效果,以除尘效率和系统阻力为参照,选定喉管气速、振弦栅数、纤维丝间隙和喉管液气比进行单因素实验。结果表明2种喷雾方式的除尘效率和系统阻力的变化趋势相同。利用SPSS软件进行4因素3水平正交实验设计,在特定参数条件下,2种喷雾方式的因素影响排序相同,除尘效率为纤维栅数＞纤维丝间隙＞喉管气速＞喷雾量;系统阻力为喉管气速＞纤维栅数＞纤维丝间隙＞喷雾量;径向外喷最佳配置为喉管气速24 m/s、喷雾量2.3 L/min、2块间隙为0.8 mm纤维栅板;轴向喷雾为喉管气速28 m/s、喷雾量2.4 L/min、2块间隙为0.8 mm纤维栅板;在最优配置下的除尘性能为径向外喷＞轴向喷雾。     

振弦栅收集电焊烟尘特性的数值模拟

为高效、低投入地处理电焊烟尘,得到过滤系统净化电焊烟尘的最佳设计参数,选择ICEM-CFD软件建立栅过滤系统的几何模型并进行网格划分,选用标准(Standard)k-ε模型、离散相模型(DPM),利用FLUENT软件对电焊烟尘过滤效率主要影响的单因素进行模拟计算。研究结论表明,用栅过滤系统过滤电焊烟尘颗粒时,振弦栅的栅丝直径、间距所决定填充率是过滤效率的直接决定因素;栅丝层间距是过滤效率的间接影响因素;通过探究振弦栅对电焊烟尘过滤效率的影响规律,进而为振弦栅的实际应用提供理论基础。     

Location selection of emergency supplies repositories for emergency logistics management: A variable weighted algorithm

With the development of the city, the number of establishments that are proposed or under construction is increasing year by year, and if they are industries that handle flammable, explosive, toxic, harmful, and dangerous substances, the public safety will face great threats, which will bring great challenges to emergency rescue work. Therefore, providing reasonable solutions to the problem of location selection of emergency supplies repositories are necessary for improving the emergency response efficiency in chemical industrial parks. A mathematical model for location selection of emergency supplies repositories in emergency logistics management are presented considering more actual factors. The optimization objectives of the model are to minimize total transport length and cost. And then a Variable Weighted Algorithm is designed to solve the model, where an auxiliary function was constructed with different methods of building weighting factors based on the theory and method of solving multi-objective optimization problems in operational research. Simulation results show the effectiveness and feasibility of the models and algorithms presented in this paper.     

Cascade-based attack vulnerability on the US power grid

The vulnerability of real-life networks subject to intentional attacks has been one of the outstanding challenges in the study of the network safety. Applying the real data of the US power grid, we compare the effects of two different attacks for the network robustness against cascading failures, i.e., removal by either the descending or ascending orders of the loads. Adopting the initial load of a node j to be L_j=[k_j(Σ_mΓjk_m)]^α with k_j and Γ_j being the degree of the node j and the set of its neighboring nodes, respectively, where α is a tunable parameter and governs the strength of the initial load of a node, we investigate the response of the US power grid under two attacks during the cascading propagation. In the case of α<0.7, our investigation by the numerical simulations leads to a counterintuitive finding on the US power grid that the attack on the nodes with the lowest loads is more harmful than the attack on the ones with the highest loads. In addition, the almost same effect of two attacks in the case of α=0.7 may be useful in furthering studies on the control and defense of cascading failures in the US power grid.     

Automated energy management in distributed electricity systems: An EEPOS approach

The increasing capacity of distributed electricity generation brings new challenges in maintaining a high security and quality of electricity supply. New techniques are required for grid support and power balance. The highest potential for these techniques is to be found on the part of the electricity distribution grid.

This article addresses this potential and presents the EEPOS project’s approach to the automated management of flexible electrical loads in neighborhoods. The management goals are (i) maximum utilization of distributed generation in the local grid, (ii) peak load shaving/congestion management, and (iii) reduction of electricity distribution losses. Contribution to the power balance is considered by applying two-tariff pricing for electricity.

The presented approach to energy management is tested in a hypothetical sensitivity analysis of a distribution feeder with 10 households and 10 photovoltaic (PV) plants with an average daily consumption of electricity of 4.54 kWh per household and a peak PV panel output of 0.38 kW per plant. Energy management shows efficient performance at relatively low capacities of flexible load. At a flexible load capacity of 2.5% (of the average daily electricity consumption), PV generation surplus is compensated by 34–100% depending on solar irradiance. Peak load is reduced by 30% on average. The article also presents the load shifting effect on electricity distribution losses and electricity costs for the grid user.     

电网规划环境影响评价的难点及对策建议

我国电网规划环境影响评价工作正处在起步阶段,缺乏成熟的理论方法和指标体系。结合常州市“十二五”电网发展规划环境影响评价工作,探讨了电网规划环评中存在的难点和问题并提出了相应的对策建议。