大落差原油管道投产充水过程研究

为了探究大落差管道充水投产过程中存在的不满流及低点超压问题,以中缅原油管道怒江跨越段为例（其最大高差达1 480 m）,基于OLGA多相流瞬态模拟方法,对大落差原油管道充水过程进行仿真研究,重点分析到达管道不同低点位置的最大速度、压力及相应持液率,得到不同输量条件下不同低点位置的水流速度、压力及持液率随时间变化规律。结果表明:当输量为900~2 000 m3/h时该管道中存在的段塞流概率降低57%,同时减少了管压波动以及对管道和设备的破坏,提高了管道输送效率。     

长江干线中下游溢油应急设备点选址优化

为优化长江干线中下游溢油应急设备点选址,建立溢油应急需求水域风险评价体系,采用云模型对其评价,进而构建以加权距离最小为目标的溢油应急设备点选址模型。采用自适应差分进化算法(Adaptive Differential Evolution,ADE)对其求解。将模型应用于九江港的溢油应急设备点选址,最终解算选址于瑞昌港区及彭泽港区,此评估结果与九江港实际规划相符。     

钼冶炼行业发展循环经济探析

根据目前我国钼冶炼行业的生产现状,通过对三氧化钼的焙烧、钼铁冶炼主要生产工艺、产污环节及污染治理情况进行总结分析,重点阐述二氧化硫、烟尘和铼回收利用后的经济效益,说明环保治理可成为钼冶炼行业的经济增长点,发展钼冶炼循环经济是必然的选择。     

On the Relationship Between Mean and Variance of Soil Moisture Fields1

Abstract: The objective of this work was to explain an apparent contradiction in the literature related to the relationship between mean and variance (or standard deviation) of soil moisture fields. Some studies found an increase in soil moisture variance with decreasing mean soil moisture, while others showed a decrease. The evidence of maximum variance in the mid‐range of mean soil moisture was also reported in the literature. In this paper, we focus on the effects of spatial variability of soil texture on the relationship between variance and mean of soil moisture during soil dry‐down processes. Soil texture influences soil moisture mean and variance through its direct effects on evaporation and drainage, which are two main factors controlling soil drying. A differential equation describing soil moisture dry down is proposed and studied. Our study shows that as mean soil moisture is greater than a threshold, variance increases with decreasing mean soil moisture. If mean soil moisture is less than the threshold, variance decreases with decreasing mean soil moisture. The threshold depends on soil texture and is between the field capacity and the wilting point. The soil moisture dry‐down equation is also applied to explain the apparent contradiction with regard to the relationship between mean and variance of soil moisture fields reported in the literature.     

Generic scenario for the impact of cooling lubricants into the hydrosphere

According to directive 93/67/EEC of the European Commission, this paper deals with the generic exposition evaluation of the environmental concentration of cooling Lubricant chemicals from the metal working industry into the hydrosphere. After considering the relevant life-cycle steps and the selection of a representative point source for the 'reasonable worst case', the emission per day Elocal(water) is determined. It leads to the predicted environmental concentration (PEClocal(water)) for the local stage in the compartment water. In order to gain the PEClocal(water) for an example--a corrosion inhibitor as additive in a cooling lubricant--, the relevant emission paths and the corresponding representative point source are described for the reasonable worst case. For non-water-miscible cooling lubricants, none of the operations in the life cycle leads to a release into the compartment water. To evaluate the hazard potential for cooling lubricant chemicals, the complete risk assessment has to be done. Also, the assessment has to be done for all high production volume chemicals, new substances and existing hazard chemicals. This means that even industrial categories like chemicals used in the textile industry or biocides and others have to be evaluated.     

西部农村沼气建设现状与对策

阐述了大力发展西部农村沼气建设的必要性和可行性．并就如何发展沼气建设提出了一些建议和解决方案。     

HERBICIDES AND TRANSFORMATION PRODUCTS IN SURFACE WATERS OF THE MIDWESTERN UNITED STATES1

ABSTRACT: Most herbicides applied to crops are adsorbed by plants or transformed (degraded) in the soil, but small fractions are lost from fields and either move to streams in overland runoff, near surface flow, or subsurface drains, or they infiltrate slowly to ground water. Herbicide transformation products (TPs) can be more or less mobile and more or less toxic in the environment than their source herbicides. To obtain information on the concentrations of selected herbicides and TPs in surface waters of the Midwestern United States, 151 water samples were collected from 71 streams and five reservoir outflows in 1998. These samples were analyzed for 13 herbicides and 10 herbicide TPs. Herbicide TPs were found to occur as frequently or more frequently than source herbicides and at concentrations that were often larger than their source herbicides. Most samples contained a mixture of more than 10 different herbicides or TPs. The ratios of TPs to herbicide concentrations can be used to determine the source of herbicides in streams. Results of a two‐component mixing model suggest that on average 90 percent or more of the herbicide mass in Midwestern streams during early summer runoff events originates from the runoff and 10 percent or less comes from increased ground water discharge.     

OPTIMIZATION PROCEDURE FOR COST EFFECTIVE BMP PLACEMENT AT A WATERSHED SCALE1

ABSTRACT: A combinatorial optimization procedure for best management practice (BMP) placement at the watershed level facilitates selection of cost effective BMP scenarios to control non point source (NFS) pollution. A genetic algorithm (GA) was selected from among several optimization heuristics. The GA combines an optimization component written in the C++ language with spatially variable NFS pollution prediction and economic analysis components written within the Arc View geographic information system. The procedure is modular in design, allowing for component modifications while maintaining the basic conceptual framework. An objective function was developed to lexicographically optimize pollution reduction followed by cost increase. Scenario cost effectiveness is then calculated for scenario comparisons. The NPS pollutant fitness score allows for evaluation of multiple pollutants, based on prioritization of each pollutant. The economic component considers farm level public and private costs, cost distribution, and land area requirements. Development of a sediment transport function, used with the Universal Soil Loss Equation, allows the optimization procedure to run within a reasonable timeframe. The procedure identifies multiple near optimal solutions, providing an indication of which fields have a more critical impact on overall cost effectiveness and flexibility in the final solution selected for implementation. The procedure was demonstrated for a 1,014‐ha watershed in the Ridge and Valley physiographic region of Virginia.     

煤炭自燃位置的分析与查找

从分析煤炭自燃的条件出发,提出了火源点的分析原则,并应用这些原则对兴隆庄煤矿的煤炭自燃情况进行了具体分析。     

Trend surface analysis of forest landscape pattern in Guandishan forest region of Shanxi,China

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