水功能区水质响应系数计算研究

水质响应系数是计算水环境容量,进而明确排污责任主体的重要基础。以一维对流扩散方程为基础,基于线性叠加原理,推导了水质响应系数矩阵,探讨了基于综合水动力水质模型的水功能区水质响应系数矩阵高效计算方法。基于HEC-RAS模型建立了辽河干流水动力水质模型,据此计算了辽河干流水功能区水质响应系数矩阵。结果表明:基于综合水动力水质模型的水功能区水质响应系数矩阵高效计算方法可显著提高计算效率,而且HECRAS模型不仅在水动力模拟方面优势显著,在水质模拟方面亦表现出良好特性。较之公式法,基于综合水动力水质模型计算水功能区水质响应系数可以显著提高计算精度。

基于水质响应系数的浅水湖泊水环境容量计算方法

根据湖泊污染物迁移转化机理、质量守恒原理,提出浅水湖泊污染物浓度场稳定判别方法。根据湖泊浓度场稳定后水质控制点污染物浓度与各入湖河道污染物通量的响应关系,构建多入湖河流水质响应系数矩阵,并采用线性规划法求解浅水湖泊各入湖河道水环境容量。与常规方法相比,该方法充分考虑了多入湖河流入湖污染物通量的叠加影响,提高了湖泊水环境容量的计算精度。

黄山市新安江流域水环境保护及河流水质排名

新安江是黄山人的母亲河,黄山市大力推进生态环境保护及水污染防治工作,确保水环境质量稳中趋好。本文简要介绍了黄山市为保护新安江水质而采取的各项措施和取得的成效,并对如何通过水质排名的方式促进黄山市地表水环境质量持续改善进行了探讨。运用水质指数法对新安江河流水质进行排名是一项有益的尝试,这对其他地方的生态环境保护和水污染防治工作起到借鉴作用。

新沟河工程应急调水效果评估

为探究新沟河工程应急调水的相关问题,评估工程实际调度效果,基于新沟河工程应急调水试验期间实测水量水质数据,采用水质综合污染指数法,引入水质改善系数、类别变化指数等分析评估了新沟河工程沿线水质对引水的响应规律。结果表明:调水试验期间新沟河西支分流比为0.30~0.59,受到西支分流的影响,新沟河东支入太湖日均流量占新沟河日均引江流量的9%~22%,长江来水对京杭运河以南东支的影响时间约为西直湖港北枢纽开启并持续引水3 d后;干流水质改善效果与本底水质以及断面距离来水水源的远近有关,本底综合污染指数较大的断面,其最大水质改善系数总体较大,当断面本底水质状况接近时,距离来水水源较近的断面水质改善系数较大。

机载激光测深海水后向散射包络的频域分析

根据机载激光测深海水后向散射雷达方程 ,在机载激光测深系统典型参数情况下 ,详细分析了海水衰减系数、海水反照率、飞机高度以及光学接收系统全视场角对海水后向散射频谱的影响。得到了 :当衰减系数C从 0 .2 /m变到 0 .9/m时 ,后向散射包络频谱将展宽2 36MHz ;当海水反照率ω从 0 .1变到 0 .9时 ,后向散射包络频谱将展宽 2 2 0MHz ;机载激光测深系统接收视场角和飞机高度对系统探测到的海水后向散射包络频率无显著影响 ;当最小可探测功率Pb=1.5 6× 10 - 10 W时 ,在典型的实验参数条件下后向散射包络的频率范围为 0 <f<5 .6× 10 8Hz。

河南省水资源资产与负债研究

开展水资源资产与负债研究,对于促进水资源管理、优化水资源配置等具有重要意义。在综合考虑水质、水量和用水效率等因素基础上,运用定量评价模型,研究了河南省2006—2016年水资源资产和负债动态演变趋势。结果表明:①全国先进用水产值均大于平均用水产值,建筑业与服务业最高,其次为工业、虚拟生态业,农业最低;全国单方水产值、单方水资源资产和用水总产值不断增长,呈现良好发展态势。②河南省农业用水效率系数最大,其次为工业、虚拟生态业,建筑业与服务业年均值最小;综合用水效率系数呈现同样的趋势。③河南省综合水质系数呈现先降后升的变化趋势,资产综合系数略有波动但差值较小,负债综合系数呈波动减小趋势。④河南省水资源总资产及人均资产呈波动变化趋势,整体水平显著提高;水资源总负债及人均负债均呈现上升—下降—上升的波动趋势,水资源净资产及人均净资产均呈波动增加趋势。

基于分质供水的区域水资源配置

水资源的优化配置是提高水资源高效利用的一种有效途径,基于水量的水资源配置无法体现水资源在水质方面的区别。分质供水在我国已经起步,但还没有广泛推广。因此建立基于水质的区域水资源优化配置模型,并进行了实例应用研究。

飞来峡水利枢纽库区动态纳污能力计算研究

根据飞来峡水利枢纽库区水流及水质特点,选取不同设计流量,建立二维水流水质模型.通过水槽实验,拟合水质衰减系数与流速的关系曲线,以获取模型水质计算参数.研究结果表明：通过概化排污口排污量与混合带长度响应关系计算,确定各排污口混合带长度在1 300～2 500m之间;在90％最枯月、50％最枯月及多年平均流量水文条件下,飞来峡库区干流水域COD纳污能力分别为162 107.7t、199 220.2t及372 104.3t; NH3-N纳污能力分别为2 757.4t、3 408.4t和6 276.4t;飞来峡库湾的纳污能力远小于库区干流水域,库湾COD纳污能力仅相当于干流的25％,NH3-N纳污能力仅相当于干流的5％;飞来峡库区纳污能力年内逐月差异显著,其中汛期（4～9月）纳污能力较大,COD、NH3-N纳污能力约占全年纳污能力的58％,飞来峡库区年内月纳污能力与月平均流量呈现较好的正相关关系.

基于水足迹理论的赣江上下游城市生态补偿研究

水足迹理论和流域生态补偿是当前研究领域的两大热点。基于水资源可持续利用的理念,将水足迹方法运用于生态补偿,构建流域间生态补偿的标准模型,同时引入水质修正系数(KQ)对模型进行完善,使之更具有实用性和可行性。文章以赣江流域生态补偿为例,通过对位于上游的赣州市和下游的南昌市的水生态安全性进行评判,运用"保护者受益、受益者补偿"的原理,得出南昌市作为受益区,应对生态保护投入者的赣州市进行补偿,经核算得出,在2010-2014年5年期间,南昌市应支付19.92亿元给赣州市,以分摊其投入成本。

STUDY ON MASS TRANSFER IN SEPARATION OF ESSENTIAL OILS FROM PLANT MATERIALS BY STEAM DISTILLATION

The mass transfer model describing the separation of essential oils from plant materials has been proposed and the mass transfer coefficient has been obtained by fitting the present model to the experimental data for three kinds of plant materials. The validity of the model has been verified. To im' prove the vapor-solid contact, a mechanical agitator has been installed in the steam distillator. The effect of agitating rate on mass transfer coefficient has also been examined.

Effect of copper on the growth of shrimps Litopenaeus vannamei : water parameters and copper budget in a recirculating system

Shrimps( Litopenaeus vannamei) were intensively cultured in a recirculating aquaculture system for 98 days to investigate effects of 0.3 mg/L Cu on its performance, Cu budget, and Cu distribution. Shrimps in Cu-treated systems had greater mean final weight(11.10 vs 10.50 g), body length(107.23 vs 106.42 mm), survival rate(67.80% vs 66.40%), and yield(6.42 vs 5.99 kg/m 3), and lower feed conversion ratio(1.20 vs 1.29) than those in control systems but the differences were not significant. Vibrio numbers remained stable(10 4 –10 6 colony forming units/mL) in the rearing tanks of both control and treated systems. Total ammonium-N, nitrite-N, nitrate-N, pH, chemical oxygen demand, 5-day carbonaceous biochemical oxygen demand, and total suspended solids were similar in controls and treatments. Dissolved Cu concentration in the treated systems decreased from 0.284 to 0.089 mg/L while in the control systems it increased from 0.006 2 to 0.018 mg/L. The main sources of Cu in the treated systems were the artificially added component(75.7% of total input), shrimp feed(21.0%), water(2.06%), and shrimp biomass(1.22%). The major outputs of Cu occurred via the mechanical filter(41.7%), water renewal(15.6%), and draining of the sediment trap(15.1%). The foam fractionator removed only 0.69% of total Cu input. Harvested shrimp biomass accounted for 11.68% of Cu input. The Cu concentration of shrimps in the Cu-treated systems(30.70 mg/kg wet weight) was significantly higher than that in control systems(22.02 mg/kg). Both were below the maximum permissible concentration(50 mg/kg) for Cu in seafood for human consumption in China. Therefore, recirculating systems can be used for commercial on-growing of Litopenaeus vannamei without loss of shrimp quality, even in water polluted by 0.30 mg/L Cu. The mechanical filter is the main route for Cu removal.

Slope stability analysis of Southern slope of Chengmenshan copper mine,China

The engineering geology and hydrogeology in the southern slope of Chengmenshan copper mine are very complicated,because there is a soft-weak layer between two kinds of sandstones.Field investigations demonstrate that some instability problems might occur in the slope.In this research,the southern slope,which is divided into six sections(I-0,I-1,I-2,II-0,II-1 and II-2),is selected for slope stability analysis using limit equilibrium and numerical method.Stability results show that the values of factor of safety(FOS) of sections I-0,I-1 and I-2 are very low and slope failure is likely to happen.Therefore reinforcement subjected to seismic,water and weak layer according to sections were carried out to increase the factor of safety of the three sections,two methods were used;grouting with hydration of cement and water to increase the cohesion(c) and pre-stressed anchor.Results of reinforcement showed that factor of safety increased more than 1.15.

Influence of Osmotic Dehydration with High Electric Field on the Drying Kinetics and Mass Transfer of Green Apples

Traditional thermal methods of drying food have often led to loss of flavours, nutrients, vitamins, etc., which encourages non-thermal pretreatments such as osmotic dehydration （OD） and/or high electric field （HEF） application to improve the overall product quality. The aim of this study was to evaluate the effect of osmotic dehydration （50% sucrose） with high electric field strengths of 0.5 and 1.0 kV/cm as pretreatments on the drying kinetics and mass transfer of green apples during convective drying at 65 ~C and microwave drying at 1 W/g. The added value of the OD and HEF on the drying kinetics, and the effective mass transfer coefficients of the subsequent drying methods were investigated through this research. The efficacy of these pre-treatments was assessed and compared using cell disintegration index, product texture and thus bring forth new correlations between these pre-treatments and the cell disintegration index using dielectric spectroscopy and its effect on the product texture.

Development of Heat Transfer Coefficient and Friction Factor Correlations for Serrated Fins in Water Medium using CFD

Abstract： The most popularly used fin types in compact heat exchangers are the serrated fins, wavy fins, louvered fins and plain fins. Amongst these fin types the serrated fins assume lot of importance due to its enhanced thermo-hydraulic performance. Thermo-hydraulic design of CHEs （Compact heat exchangers） is strongly dependent upon the predicted/measured dimensionless performance （Colburnj factor and Fanning friction vs. Reynolds number） of heat transfer surfaces. This paper describes the numerical analysis to study the heat transfer coefficient and friction factor of Serrated fins in water medium. CFD （Computational fluid dynamics） methodology has been used to develop the single phase water heat transfer coefficient and friction factor correlations for serrated fins using ANSYS Fluent 14.5. The results are compared with previous air-cooled models and experimental results of water. The water cooled CFD analysis results shows that the Prandtl number has a large effect on the Nusselt number of the serrated fin geometry. Finally, the generalized correlations are developed for serrated fins taking all geometrical parameters into account. This numerical estimation can reduce the number of tests/experiments to a minimum for similar applications.

Copper partitioning between granitic silicate melt and coexisting aqueous fluid at 850°C and 100 MPa

Experiments on the partitioning of Cu between different granitic silicate melts and the respective coexisting aqueous fluids have been performed under conditions of 850 ℃, 100 MPa and oxygen fugacity （fO2） buffered at approaching Ni-NiO （NNO）. Partition coefficients of Cu （Dcu = Cfluid/Cmelt） were varied with different alumina/alkali mole ratios [Al2O3/（Na2O ＋ K2O）, abbreviated as Al/ Alk], Na/K mole ratios, and SiO2 mole contents. The DCu increased from 1.28 ± 0.01 to 22.18 ±0.22 with the increase of Al/Alk mole ratios （ranging from 0.64 to 1.20） and Na/K mole ratios （ranging from 0.58 to 2.56）. The experimental results also showed that Dcu was positively correlated with the HCl concentration of the starting fluid. The Dcu was independent of the SiO2 mole content in the range of SiO2 content considered. No Dcu value was less than 1 in our experiments at 850 ℃ and 100 MPa, indicating that Cu preferred to enter the fluid phase rather than the coexisting melt phase under most conditions in the melt-fluid system, and thus a significant amount of Cu could be transported in the fluid phase in the magmatichydrothermal environment. The results indicated that Cu favored partitioning into the aqueous fluid rather than the melt phase if there was a high Na/K ratio, Na-rich, peraluminous granitic melt coexisting with the high Cl^- fluid.

Effects of Soil pH，Texture，Moisture，Organic Matter and Cadmium Contenton Cadmium Diffusion Coefficient

The supply of cadmium from soil to plant roots mainly depends on the diffusion process. This work was conducted tostudy the effect of some soil properties on cadmium diffusion coefficient (D) in soil. Measurements were made using the Shofield and Graham-Bryce's isotopic labelling method. Cadmium diffusion coefficients varied from 10￣(-7) to 10￣(-9) cm￣2s￣(-1),Higher values were observed in acid sandy soils and lower values in calcareous clay soils. Liming an acid soil resulted in a sub-stantial decrease of D. Addition of cadmium as nitrate salt generally increased D, while addition of sewage sludge and organ-ic matter resulted in a significant decrease of cadmium diffusion. The rhizospheric activity also induced a moderate reduction in D. The relationships between D 10￣(-9)cm￣2s￣(-1)) on the one hand and soil PH, moisture (Mc, g kg￣(-1)), organic matter (OM, gkg￣1 ), clay (Cy, g kg￣(-1)) and cadmium content (Cd, mg kg￣(-1)) on the other were obtained by the multigle regression:D=182. 1-29.g1 pH+0.210Mc-0.303OM+0.011Cy+1.64Cd (R￣2=0.859,n=22 ).

EFFECTS OF ROCK BEHAVIOR AND STRESS CONDITION ON FIELD STRESS DETERMINATION

Non-consistency of stress results is of ten observed during field measurements. In some cases, even the rneasurernents are made at the same location in a massive rockrnass, the results can vary widely. In order to solve the problem, extensive research has been carried out to study the major factors wh1ch rnay affect stress deterrnlnation. They include the rock behaviour and the stress state. For rocks showing non-isotropic behaviour, the values of Young’s modulus and Poisson ratio vary with the orientation of loading and measurement. Stress condition in the rock affects the rock behaviour. Furtherrnore, the loading condition on rock samples durlng laboratory tests is different from in the field and therefore the determined e1astic constants may not represent the field condi tion. In general , the Young’s modulus may depend on the orientation, the loading path, the stress magnitude and the stress ratio. This paper examines in detail the effects of those factors, especially for rocks showing transversely isotropic behaviour. It is found that the discrepancy of stress results from field measurernents in this type of rock is mainly due to over simplification of the rock behavior and inadequate use of elastic constants of the rock during stress calculation. A case study is given,which indicates the significance of these factors and demonstrates the proper procedure for stress calculation from measurements.

Estimation of Pool Boiling Heat Transfer Coefficients of Ethanol-Water Mixtures

Based on the analysis of the principles of heat and mass transfer from the liquid bulk to bubble surface during nucleation, a new estimation method to predict the heat transfer of the nucleate pool boiling in binary mixtures is proposed in this paper by using the heat and mass transfer analogy (Colburn analogy) at the bubble surface transfer layers. With the use of Thome's concept of boiling range, an approximate method is derived to realize the calculation. The predicted results by this method are in good agreement with the experimental data from different sources.

Effect of attack angle change on hydrodynamic character of supercavitating bodies

A series of experiments has been done in a moderate-velocity cavitation tunnel to investigate the effects of attack angle change on hydrodynamic characters of supercavitation. Hydrodynamic characters of the aft section at various attack angles were compared. The investigation shows that hydrodynamic forces of the aft section are dependent of supercavity shapes at different attack angles,and the magnitude of hydrodynamic forces of the aft section varies with the change of attack angle. When the aft section is in the fully wetted case,the drag coefficient changes little. Lift and moment coefficients both increase with the increased attack angle,and the increase magnitude is not large. When the aft body planing is on the cavity boundary,the drag coefficient of nonzero attack angle is larger than that of zero attack angle,and the maximal lift and moment coefficients both vary obviously with the increased attack angle. In the case that the body is fully enveloped by cavity,the drag coefficient,lift coefficient and moment coefficient are nearly constant with the change of attack angles.

Landslide stability for Shuitianba in the Three Gorges area

According to the data of preliminary survey, the authors established a landslide geological model,on the basis of analyses on the sensitivity of landslide, tried to simulate and calculate the landslide stability of Shuitianba with the method of transfer coefficient when it is under different strength parameters, and study the landslide mechanism. The results show that it is sensitive to the effects of shear strength parameters of sliding zone and groundwater level on landslide stability safety coefficient, which provides reliable basis for calculation of landslide stability.