Monitoring and Evaluation of Air Pollution at Ohaji/Egbema Flow Station and Its Environs via GPS in Ohaji Egbema Lga, Imo State Nigeria

The work of “Monitoring and Evaluation of Air Pollution” the main aim of this work is to measure the concentrations of gases which include CO2, CO, NOx, SOx and thermal radiation and carry out an analysis of the measured data. This experiment was scheduled to take place at Egbema flow station which is managed by NPDC (Nigerian Petroleum Development Commission) Shell location 2 in Obiakpu, Ohaji Imo state. The bad effects of these pollutant gases on the community can include cause of diseases to plants and animals, causes of physical ailments in the respiratory tract of humans, and death and degradation of the surrounding environment. The parameters measured during this exercise include the distance from the flow station, latitude and longitude of the distance measured on the earth’s surface, time for the experiment and the concentration of pollutant gases. The instrument used includes CO meter, CO2 meter, SOx and NOx meters, and thermal radiation meter. The gases were measured in three different time intervals between 10:50 am - 11:23 am (for CO: 0.02 ppm, 0.01 ppm, 0 ppm, 0 ppm, 0.01 ppm, 0 ppm;for CO2: 0.04 ppm, 0.01 ppm, 0.01 ppm, 0.02 ppm, 0.01 ppm, 0 ppm;for SOx: 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3;for NOx: 0.127 mg/m3, 0.098 mg/m3, 0.12 mg/m3, 0.122 mg/m3, 0.113 mg/m3, 0.103 mg/m3;for thermal radiation: 57.4 W/m2, 61.5 W/m2, 65.1 W/m2, 64.9 W/m2, 81.9 W/m2, 148.3 W/m2), 1:30 pm - 2:13 pm (for CO: 0.01 ppm, 0.02 ppm, 0 ppm, 0 ppm, 0.1 ppm, 0 ppm;for CO2: 0.01 ppm, 0.01 ppm, 0.01 ppm, 0.01 ppm, 0 ppm, 0 ppm;for SOx: 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3;for NOx: 0.122 mg/m3, 0.117 mg/m3, 0.114 mg/m3, 0.115 mg/m3, 0.122 mg/m3, 0.11 mg/m3;for thermal radiation: 120.5 W/m2, 132.8 W/m2, 156.7 W/m2, 170.5 W/m2, 148.5 W/m2, 95.1 W/m2) and 5 pm - 5:37 pm (for CO: 0.02 ppm, 0.1 ppm, 0.1 ppm, 0 ppm, 0 ppm, 0 ppm;for CO2: 0.03 ppm, 0.2 ppm, 0.1 ppm, 0.1 ppm, 0 ppm, 0.1 ppm;for SOx: 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3;for NOx: 0.128 mg/m3, 0.118 mg/m3, 0.119 mg/m3, 0.117 mg/m3, 0.124 mg/m3, 0.114 mg/m3;for thermal radiation: 121.4 W/m2, 133.3 W/m2, 160.2 W/m2, 177 W/m2, 161.4 W/m2, 97.2 W/m2) at distances of 0 m, 100 m, 300 m, 500 m, 1000 m and 1500 m respectively. From the values gotten from the gas concentration measurements, we can say that SOx gases are either minute or not available in the environment. Also, from the graph analysis carried out on the gases, we can also say that CO2 concentration is either increasing or at the same level throughout the distance while the concentrations of NOx, CO and thermal radiation reduce with increasing distance. On the part of the “averaging time model” used in the analysis, we can say that at increasing averaging times the concentration of gases reduces. Analysis of whether the environment is polluted and with which gas exactly is also carried out using the Air quality index and it was deduced that the environment is polluted with NOx gases because the concentration is above the normal environmental ambient temperature.

Debris flow susceptibility analysis based on the combined impacts of antecedent earthquakes and droughts： a case study for cascade hydropower stations in the upper Yangtze River, China

The upper Yangtze River region is one of the most frequent debris flow areas in China. The study area contains a cascade of six large hydropower stations located along the river with total capacity of more than 70 million kilowatts. The purpose of the study was to determine potential and dynamic differences in debris flow susceptibility and intensity with regard to seasonal monsoon events. We analyzed this region's debris flow history by examining the effective peak acceleration of antecedent earthquakes,the impacts of antecedent droughts, the combined effects of earthquakes and droughts, with regard to topography, precipitation, and loose solid material conditions. Based on these factors, we developed a debris flow susceptibility map. Results indicate that the entire debris flow susceptibility area is 167,500 km^2, of which 26,800 km^2 falls within the high susceptibility area, with 60,900 km^2 in medium and 79,800 km^2 are in low susceptibility areas. Three of the six large hydropower stations are located within the areas with high risk of debris flows. The synthetic zonation map of debris flow susceptibility for the study area corresponds with both the investigation data and actual distribution of debris flows. The results of debris flow susceptibility provide base-line data for mitigating, assessing, controlling and monitoring of debris flows hazards.

Design of Expressway Toll Station Based on Neural Network and Traffic Flow

This paper is concerned with the design of expressway toll station problem based on neural network and traffic flow. Firstly, the design of the toll plaza is mainly through analyzing the daily traffic flow, different charging mode of construction cost and waiting time of the United States. Secondly, exploring traffic conditions is divided into two kinds, based on the traffic flow speed-density flow model. Then, a fuzzy-BP neural network model is constructed, with capacity, cost, and safety factor as the input layers and performance as the output layer. It is concluded that this scheme will reduce the occurrence of traffic accidents, so it is desirable. Considering that the increase in unmanned vehicles will lead to an increase in safety performance, we increase the number of electronic toll stations to improve security performance and reduce the occurrence of traffic accidents.

HYDRAULIC CALCULATION AND MEASUREMENT OF FLOW FIELD WITHIN INLET PASSAGE OF LARGE PUMPING STATION

By means of the analysis of the internal flow within inlet passage of large pumping sta-tion, an analysis of 3-D direct boundary element for the flow has been presented on the potentialflow assumption, and a calculation and an experimental proof for the inlet passage of 30 angle-type axial pumping station have been made. Based on the analysis of the calculations and theexperiments, the calculation method is feasible and believable.

Three-dimensional CFD simulation of inlet structure flow in pumping station based on Eulerian solid- liquid two-phase flow model

Sediment deposition in the pumping station has a huge negative impact on unit operation.The three-dimensional CFD method has been used to simulate inlet structure flow in pumping station based on the Eulerian solid- liquid two-phase flow model. The numerical results of the preliminary scheme show that sediment deposition occurs in the forebay of pumping station because of poor flow pattern therein. In order to improve hydraulic configuration in the forebay,one modified measure reconstructs water diversion weir shape,and another measure sets a water retaining sill in the approach channel. The simulation results of the modified scheme prove that back flow in the forebay has been eliminated and the sediment deposition region has also been reduced.

Debris Flow Monitoring System and Observed Event in Taiwan:A Case Study at Aiyuzi River

Since 2002, the Soil and Water Conservation Bureau, which is responsible for the conservation and administrative management of hillside in Taiwan, has been cooperating with Feng Chia University. Together, they have successfully carried out the establishment and maintenance of 13 fixed debris flow monitoring stations over the island and 2 mobile debris flow monitoring stations. During July 2004, a powerful southwest air current brought by Mindulle Typhoon caused serious flood in central and southern Taiwan. This paper aims to describe the establishment of debris flow monitoring systems in Taiwan and the observation of the debris flow event during Mindulle Typhoon at Aiyuzi River in Shenmu Village, Nantou County by the monitoring station.

Mapping of Stream Flow Trends in Porsuk Basin Using GIS Environment

In this study, trends of minimum, average and maximum flows were investigated in Porsuk basin, which is a sub-basin of Sakarya basin and then changes in flows were mapped using Geographical Information Systems (GIS). In the study, in 10 flow gauging stations across the Porsuk basin, monthly average, maximum and minimum flow data is used covering the period 1961-2013 (53 years). When analyzing the distribution of observed trends in the basin, a trend has been observed in most of the river flows. A decreasing trend has been observed overall in the basin. Trends are generally decreasing over time except for a few stations. As a result, increasing trends are observed in the west part of the basin;while in the east part of the basin decreasing trends are observed. When average and maximum monthly flows are investigated, decreasing trends are observed in the stations except DSI-12182. Trend analysis of 10 flow gauging stations across the Porsuk basin is investigated by Mann-Kendall method. Trend distribution was made according to flow trends of basin by transferring Z values to GIS.

Optimization and Algorithm for Through Train Connections at District Stations

In the optimization of train diagrams, selecting the arrival and departure paths of the through gains has a great impact on the dwell time at district stations. In this paper, on the basis of train paths and the through train connection time standard at district stations, we built a mathematical model aiming at minimizing dwell time of through trains at two adjacent district stations, and then converted this into a network flow model to which is added a source and a sink node. Then, we propose a new algorithm for solving the network flow model based on the minimum-cost flow algorithm. A case study for through trains from the Guiyang South Railway Station to the Chongqing West Railway Station shows that the algorithm is reliable and efficient for solving the problem of through train connections, and there is a reduction in the total dwell time that the through trains spend at two adjacent district stations.

深层隧道进流式泵站前池流态及整流措施研究

为改善深层隧道进流式泵站前池内的旋流、偏流等不良流态,基于RNG k-ε湍流模型对前池流态进行数值模拟,研究适用于此类城市排涝泵站的整流措施。数值计算结果表明:泵站前池、进水池内存在局部立面旋滚、螺旋流、斜向流、流速分布上高下低等不良水力现象,致使泵站进水流道水力条件不佳;采用双层环形板和两组导流墩的组合式整流措施可抑制前池、进水池中的立面旋滚、螺旋流和斜向流流态,从而有效改善流道的进水条件,提高进水流道进口处流速分布均匀度,使泵进水状况变好,提高泵站运行的可靠性。

地下泵站进水流道数值模拟与方案优化

以典型地下泵站的进水流道为研究对象,建立数值仿真模型,分析设计方案的水力特性及存在不足,并给出优化方案.研究结果表明:在原方案中,外侧水泵进水管入口中心和圆洞出口中心的连线与来流方向的夹角达到70°,水流大角度偏转,并在进水管入口出现脱流现象,水头损失系数达到2.31~2.44,水泵进水管出口的流速分布均匀度为95.09%~96.80%,速度加权平均角为86.51°~87.41°,原方案的圆洞突扩进入压力罐,然后突缩进入水泵的进水管,且压力罐内无任何导流措施,致使局部流道产生了较大的水头损失;优化方案提出了“集管+岔管”的分流措施,通过2个60°弯头实现水流流向的偏移,平面和垂直方向均没有突扩或突缩结构,水头损失系数减小至0.93~1.07,优化方案不仅改善了流道的水力性能,也避免了开挖、衬砌压力罐.研究结果可为类似地下泵站进水流道设计提供一定依据.

Orthogonal optimization of flow uniformity at exit section of elbow-inlet passages

Elbow-inlet passage is widely used in large drainage pumping stations.Flow uniformity at the exit section directly determines its hydraulic performance.Flow uniformity must be optimized to improve the operational efficiency of the large axial-flow pumping station.Modeling and numerical simulation methods were used to investigate the elbow-inlet passage,and the accuracy of the calculation results was verified.The key geometric parameters affecting the uniformity of the flow were optimized by the orthogonal experiment design.The optimal schemes were obtained and compared with the original scheme.The results show that flow uniformity V u after optimization is 95.41%,which is increased by 1.04%.The pumping station efficiency is increased by 1.89%,thereby confirming the applicability and accuracy of the proposed scheme,especially for the optimization of flow uniformity of the exit section of the elbow-inlet passage.

考虑交通流量俘获的电动汽车充电负荷预测和充电站规划

针对电动汽车(EV)的充电需求,考虑路径的交通流量,以最大交通流量俘获、最小配电系统网络损耗和最小节点电压偏移为目标,构建了一个多目标决策模型对EV充电站进行规划。运用网络扩展技术确定交通流量俘获路径;运用蒙特卡罗模拟算法,确定规划区内EV的最大充电负荷,从而推算得到充电站的容量;运用超效率数据包络分析评价方法,确定经过归一化处理后各目标函数的权重系数,从而将多目标优化问题转化为单目标优化问题,并采用改进的二进制粒子群优化算法进行求解。以一个包含25个节点的交通网络耦合33节点配电系统为算例进行仿真,验证所建模型和所提方法的有效性,并进一步分析EV最大行驶里程、充电站负荷接入不同节点以及不同时刻对各目标函数的影响。

沙集泵站改造叶轮选型及流道改形研究

针对沙集泵站空化汽蚀较为严重,在工程加固改造时主体结构不变,无法通过降低站房底板增加叶轮淹没深度,从而提高空化性能的实际问题,采用计算流体动力学CFD方法,考虑泵站进口不同水位,对水泵装置全流道内部流动进行数值分析,研究水泵空化和能量特性。小幅降低叶轮中心高程,不仅未能减小空化范围,反而降低了泵装置效率,不宜采用。通过优选水泵水力模型、降速、增径并适当修整流道等方法,在保证泵装置能量性能的前提下,提高水泵空化性能。结果表明,采用方案一:叶轮直径增至1.68 m,转速降至250 r/min,基本消除了叶片进水边附近的附着空化,同时能够满足泵站特征水位组合下的流量和效率。成果也可用于类似泵站的设计和机组的选型。

铁路枢纽双编组站静态配流协同优化研究

枢纽内跨编组站进行协同配流有助于优化枢纽内的车流接续,提高全局配流质量。引入跨编组站协同配流思想,构建铁路枢纽双编组站静态配流协同优化模型,以最小化双编组站的配流总代价、最大化双编组站的总满轴列车数为优化目标,考虑车流量约束、列车到解编发作业与枢纽小运转列车走行的接续时间约束、出发列车满轴与不违编约束、调机资源使用约束。以列车等级、编组去向数及出发时刻排序作为配流代价。设计理想点算法将多目标转化为单目标进行求解,最后运用算例对模型及算法的有效性进行验证。结果表明,双编组站联合配流相较于两编组站单独配流,可使满轴列车总数增加1列、站存车总数减少13辆、配流总代价降低5.4%,从而达到更佳的配流效果。

考虑交通流量预测的光−氢−电耦合系统规划

为解决制氢、加氢站建设成本高、氢燃料汽车加氢具有不确定性特点等问题,提出一种考虑交通流量预测的光−氢−电耦合系统规划模型。首先,建立包含氢气生产、压缩和储存并通过充氢装置注入至氢燃料电池汽车内的现场制氢模型;其次,提出交通流量的预测方法,为制氢、加氢站系统建模和运行提供支持;最后,以最小化成本为目标,构建考虑交通流量预测的光−氢−电耦合系统规划模型,然后以IEEE30标准算例,以30路网节点为算例分析系统,研究发现制氢、加氢站联合光伏电站有利于降低系统成本;制氢补贴政策的实施使氢气需求增加28%,制氢、加氢站数量增加20%;电解槽制氢量快速响应峰谷分时电价变化。结果表明所提模型具有有效性。

2D—flow程序在罗南泵站强透水基础渗透分析中的应用

2D—flow程序是日本软脑株式会社研制开发的平面有限元两维渗流计算程序,计算结果准确、直观,在大量涉及渗流问题的工程中已得到验证。以罗南泵站工程为实例,介绍了2D—flow程序的原理及在该工程应用中的参数选择、计算模型和主要计算过程。

抽蓄电站无压隧洞交叉区体型优化试验研究

交叉无压隧洞交汇区域水流的水力特性复杂,无压隧洞交叉区体型及交汇口水流水力特性的研究对确保水利枢纽的安全运行具有重要的工程意义。基于物理模型试验,对某抽水蓄能电站下水库高落差泄洪排沙洞和放空洞交叉区体型进行优化,最终确定圆弧连接+交叉角21°的交叉区体型。对比分析圆弧连接+交叉角21°的交叉区优化体型下特征试验工况的水力特性。结果表明,6种特征试验工况下,泄洪排沙洞和放空洞交叉口及下游均为急流,明流泄洪且流态较稳定,均在交汇口下游右边直墙处形成最大水深,水深低于直墙高度,满足水面线不宜超过直墙范围的要求。

抽蓄电站全库盆防渗水库渗流缺陷影响分析

针对抽蓄电站全库盆防渗水库土工膜缺陷导致水库渗流量产生变化的安全问题,结合陕西省某抽蓄电站水库库底土工膜防渗工程,采用单因素影响分析和多因素影响分析方法进行抽蓄电站全库盆防渗水库渗流缺陷影响分析。结果表明,水头大小、缺陷大小、缺陷个数均正向影响抽蓄水库渗流量,而缺陷位置与抽蓄水库渗流量的相关性不明显。其中缺陷大小是影响抽蓄水库渗流量的主要因素,其次为水头大小,再次为缺陷个数。

泵站进水系统三维水动力特性数值模拟研究

【目的】研究泵站进水系统结构对水泵进水流场的影响。【方法】基于Fluent平台,假定水流为不可压缩湍流流体,在满足连续方程和动量方程的基础上,引入RNGk-ε紊流模型,对改造前后泵站进水系统进行了数值模拟,采用适于稳态流场的收敛速度更快的SIMPLEC算法,利用有限体积法进行空间离散求解,分析了不同断面的流场流速、流速旋角及流线分布,对比分析了改造前后泵站进水系统的水动力指标。【结果】改造方案各水动力指标均小于改造前方案,进水池流速标准差减小了6%~64%,进水管进口流速标准差降低了41%~96%,平均流速旋角减小了60%~73%,流速旋角标准差降低了59%~72%,水流流态分布趋向均匀,水泵进水条件明显改善。【结论】改造后泵站进水系统流速分布较均匀,流态趋于平稳,对减轻泵站机组汽蚀破坏有重要意义。