基于分形的土壤中非均匀流动的染色示踪试验与图像分析

通过采集土壤染色示踪试验中的溶质迁移动态图像,分析和研究了非饱和土壤中溶质运移的特性及其空间动态分布特征,采用Photoshop和Matlab处理数字图像并将其转化为二值图像,利用Java计算出了基于W indows平台的分形维数值。     

利用同一土柱测定土壤水分和保守性溶质运移参数

利用数学模型预测土壤水分和溶质运移过程的准确性取决于所涉及的水力参数和土壤溶质运移参数的可靠性和精度。目前由于实验系统和研究方法的限制，在测定水力参数和溶质运移参数时所采用的土壤样本不一致，产生了样本误差。本文建立了利用同一土壤样本测定水力参数和溶质运移参数方法，即首先进行水平一维入渗实验，待土壤饱和后改换为供溶液试验，测定土壤边界层随时间的变化过程从而计算出溶质运移参数。与传统的利用土壤溶质穿透曲线获得参数的方法比较表明，本文提出的方法是可行的。     

黄土区土壤溶质径流迁移过程影响因素浅析

根据室内降雨－入渗－产流过程中溶质迁移模拟实验研究结果，对降雨，有效雨滴功能，坡度，坡长，土壤溶质化学特性以土壤溶质随地表径流迁称全过程影响进行了分析，分析结果表明了雨强和有效雨滴动能与雨后表面土壤饱和含水量，土壤入渗能力，土壤水分运移深度，径流熔质浓度，径流溶质迁移总量以及径流溶质平均浓度间的关系，并根据Ｇｒｅｅｎ－Ａｍｐｔ人渗模式，推求了有效动能对土壤饱和导不率间关系，为进一步研究土壤溶质随地     

土壤中溶质运移韵研究现状及问题

随着土壤盐渍化和环境问题的日益突出，以研究土壤水中的溶质在土壤中运移过程、规律和机理的土壤溶质运移理论已被环境科学、土壤科学、农田灌溉等各个相关领域学者关注。简要介绍了土壤溶质运移理论的发展过程和国内外学者数十年来关于土壤溶质运移的研究成果，对数值模拟的研究现状、数值计算方法的应用、水动力弥散系数和延迟因子2个重要参数的测定等内容进行了一定评价，讨论了目前土壤溶质运移理论研究的不足之处。     

Langmuir吸附模式及其应用

本文综述了Ｌａｎｇｍｕｉｒ提出并建立在单分子吸附理论基础上，将土壤对溶质的吸附量和溶质液相浓度之间的关系进行定量描述的Ｌａｎｇｍｕｉｒ吸附模型，及其在应用中的发展。     

溶质运移理论的发展

关于土壤或地下水受到污染的问题,其实质是可溶性污染物在水流作用下在土壤或含水层中的运移结果,研究此问题而兴起的一门学科就是溶质运移理论。介绍了溶质运移模型、溶质运移的室内外试验研究成果和溶质运移数值模拟方法的研究现状。     

Langmuir吸附模式及其应用

本文综述了Ｌａｎｇｍｕｉｒ提出并建立在单分子吸咐理论基础上，将土壤对溶质的吸咐量和溶质液相浓度之间的关系进行定量描述的Ｌａｎｇｍｕｉｒ吸附模型，及其在应用中的发展．     

黄土区土壤溶质径流迁移过程影响因素浅析

根据室内降雨—入渗—产流过程中溶质迁移模拟实验研究结果，对降雨、有效雨滴动能、坡度、坡长、土壤溶质化学特性对土壤溶质随地表径流迁移全过程影响进行了分析。分析结果表明了雨强和有效雨滴动能与雨后表面土壤饱和含水量、土壤入渗能力、土壤水分运移深度、径流溶质浓度、径流溶质迁移总量以及径流溶质平均浓度间关系。并根据Ｇｒｅｅｎ－Ａｍｐｔ入渗模式，推求了有效动能对土壤饱和导水率间关系。为进一步研究土壤溶质随地表径流迁移提供指导。     

田间条件下土壤氮素运移的模拟模型I

将土壤ＮＨ＾＋４和ＮＯ＾－３视为土壤溶质，根据土壤溶质运移原理，选用描述地土壤溶质运移的对流－弥散模型，建立了一个田间条件下土壤运移的数值模拟模型，模型中考虑了矿化，生物固持－释放，土壤氨挥发，硝化和反硝化等转化作用，并用线性模式描述土壤铵吸附，作物根系吸收也在源汇项中，各转化参数均需用土壤温度和湿度作了进行修正，所建模型为土壤水，热和氮素联合模拟模型，对联合模型中水盐运动模块用经典经验作了检验。     

考虑土壤中硝态氮转化作用的传递函数模型

本文运用传递函数模型，模拟了冬小麦从播种至返青期地中渗透计土壤2m出流处的NO-3N浓度动态。假设模拟时段内冬小麦的根系吸氮与累积实际蒸散量成正比，计算了冬小麦的吸氮动态(汇项)；联立由田间氮素平衡法所得的净矿化项(源汇项)从而获得净源汇项。在模型中将NO-3-N在土壤中的主要转化作用作为源汇项嵌入传递函数的模型中，建立了NO-3-N这一不稳定溶质在土壤中淋失的传递函数模型。通过对比实测资料，表明作者提出的考虑NO-3-NN主要转化作用的传递函数模型较通常保守溶质的传递函数模型具有更好的仿真精度。     

考虑残留氮对非稳定流场硝态氮淋失贡献的传递函数模型Ⅱ农田应用

应用田间冬小麦-夏玉米生长条件下土壤硝态氮淋失动态的试验资料，对所提出的可估计表施和残留氮对土壤非稳定流场中硝态氮淋失贡献的传递函数模型进行了检验。首先，对所选定的农田中的两个土壤剖面，估算了硝态氮和氯离子的中值与均值迁移时间，然后，利用我们的模型，使用其中一个土壤剖面标定硝态氮和氯离子运移的概率密度函数的参数，接着，应用标定后的传递函数模型，模拟了另一个土壤剖面的硝态氮淋失浓度和累积淋失量动态，并分别估算了表施和残留氮占硝态氮总淋失量的分数。结果表明：提出的传递函数模型在农田条件下对土壤硝态氮累积淋失量模拟的相对误差为14.89%。     

非稳定流条件下非饱和均质土壤溶质运移的传递函数解

根据溶质运移的传递函数模型Tromsfer Function Model, TFM理论，研究了非稳定流条件下非饱和均质土壤中表施和原有NO-3 N及原有Cl-的运移。由极大似然法估算了模型参数μ和σ2，求出了溶质运移的概率密度函数，计算了NO-3 -N的淋失量，并利用土壤中原有Cl-的动态，对NO-3 N的迁移过程进行了模拟，同时还估算了溶质的中值迁移时间tm和均值迁移时间相应的运移体积θst和θst。     

土壤中硝态氮淋洗的传递函数模拟和预报

运用传递函数模型(Transfer Function Model,TFM)作为随机模拟工具，对灌溉入渗重分布条件下非饱和土壤中硝态氮的运移进行了数学模拟。获得了实验条件下土壤中硝态氮迁移时间的概率密度函数和中值与均值迁移时间及运移体积分数，仿真了实验期间硝态氮的出流浓度动态，估算了硝态氮的累积淋洗量。     

Development of a pH/Alkalinity Treatment Model for Applications of the Lampricide TFM to Streams Tributary to the Great Lakes

It has long been known that the toxicity of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is influenced by chemical and physical properties of water. As the pH, conductivity, and alkalinity of water increase, greater concentrations of TFM are required to kill sea lamprey (Petromyzon marinus) larvae. Consequently, the concentration of TFM required for effective treatment varies among streams. Brown trout (Salmo trutta) and sea lamprey larvae were exposed to a series of TFM concentrations in a continuous-flow diluter for 12 h. Twenty five exposures were conducted at various water alkalinities and pHs that treatment personnel encounter during lampricide treatments. Survival/mortality data were analyzed for lampricide concentrations that produced 50 and 99.9% mortality (LC₅₀ and LC_99.9) for sea lamprey larvae and 25 and 50% mortality (LC₂₅ and LC₅₀) for brown trout. Linear regression analyses were performed for each set of tests for each selected alkalinity by comparing the 12-h post exposure LC_99.9 sea lamprey data and LC₂₅ brown trout data at each pH. Mortality data from on-site toxicity tests conducted by lampricide control personnel were compared to predicted values from the pH/alkalinity prediction model. Of the 31 tests examined, 27 resulted in the LC₁₀₀s (lowest TFM concentration where 100% mortality of sea lamprey was observed after 12 h of exposure) falling within 0.2 mg/L of the predicted sea lamprey minimum lethal (LC_99.9) range. The pH/alkalinity prediction model provides managers with an operational tool that reduces the amount of TFM required for effective treatment while minimizing the impact on non-target organisms.     

Contaminant transport through fractured-porous media: An experimental study

In this paper, an experimental study has been carried out to investigate the behavior of solute transport through fractured-porous media. Experimental set-up consists of fractured-porous media which has been created with clay (matrix) and a single fracture is created in middle of the clay matrix in flow direction. During experiment, the clay matrix is saturated with fresh water and solute tracer is injected in the fracture at inlet and the samples are collected from out let for different times of interval. Concentration profiles of experimental data of chloride and fluoride are simulated with developed numerical model to estimate transport parameters. Results show that the value of matrix-diffusion coefficient depends on fracture velocity and residence time till to reach in equilibrium condition. It is also found that higher value of diffusion coefficient leads to reduce the magnitude of solute concentration in the fracture. The experimental results indicate that there is substantial diffusion and sorption in the fractured-porous matrix. The estimated parameters and numerical model can be used for design of waste disposal system in the fractured matrix system. Finally, numerical results of various temporal moments have been predicted to study the behavior of reactive solute in the fracture, and it was found that the behavior of solute mass recovers, mean arrival time and second time moment are nonlinear along the travel distance for solute in the fracture in the presence of matrix-diffusion and decay rate coefficient.     

Pedotransfer functions to determine water conducting macroporosity in South African soils

Macropores play an important role in the rapid transport of water, solutes and pollutants through the soil. Transport through these pores (>0.5 mm) is dominated by gravitational forces (i.e. matrix forces have low impact) resulting in flow rates orders of magnitude higher than rates that would be predicted, posing problems for modelling and understanding water and solute transport through soils. This study aimed to quantify the water conducting macroporosity (WCM) in a range of soils in South Africa and to develop three pedotransfer functions (PTFs) able to predict WCM. Saturated (K(s)) and unsaturated (K??) conductivities were measured in situ on 120 soil profiles using double ring and tension infiltrometers methods. Differences between K(s) and K?? in conjunction with Poiseuille's law and the capillary rise equation were used to calculate WCM. The first two multiple regression functions made use of all available soil properties influencing WCM using a 'best model' and 'backward' analysis approach respectively. The third model used only easily observable soil properties to predict the WCM. The functions were validated using a double-cross method. Results are encouraging with R2 values of 0.78, 0.74 and 0.69 for functions 1, 2 and 3 respectively.     

Modeling Lampricide Transport in the St. Marys River

This paper describes use of an integrated chemical/oil spill computer model to study lampricide transport in the St. Marys River. The model is developed based on a depth-averaged two-dimensional advection-diffusion equation using a Lagrangian discrete parcel method. The hydrodynamics in the model is computed using a depth-averaged two-dimensional finite element model. The model is used to analyze the effectiveness of alternative lampricide application strategies. This analysis showed that releasing TFM from both the Great Lakes Power Plant and the Edison Sault Power Station is more effective than releasing from the Great Lakes Power Plant only, in terms of kill-per-dollar. However, the total cost for two-site releases are higher than single-site releases. The simulations also showed that the optimum duration of TFM release is between 14 and 16 hours. Simulations of bottom velocity distribution showed that the area over which the granular Bayluscide application could cover 70 to 90% of the sea lamprey (Petromyzon marinus) population in the St. Marys River, depending on the total river discharge.     

室内滴灌施药条件下阿特拉津在土壤中运移规律的研究Ⅰ.物理模拟与参数确定

利用滴灌系统施用农药可以将农药直接作用到植物根区，这是节水农业和生态农业中一种先进的灌溉施药方法。本文详细地描述了在实验室内开展的滴灌施用除草剂一阿特拉津在土壤中运移的物理模拟实验，介绍了采用批量平衡技术和批培养方法获得阿特拉津在供试土壤中吸附特性参数和降解速率常数的实验步骤，给出了根据Freundlich吸附等温线和一级动力学方程对实验数据的拟合结果。此外，由土壤干容重及吸管法求得的土壤质地，利用土壤传递函数间接求取了van Genuchten型水力学参数，并由易混合置换实验得到了溶质运移的弥散度。本文的研究成果为进一步开展滴灌施用阿特拉律在土壤中运移规律的数值分析奠定了基础。     

室内滴灌施药条件下阿特拉津在土壤中运移规律的研究Ⅰ：物理模拟与参数确定

利用滴灌系统施用农药可以将农药直接作用到植物根区，这是节水农业和生态农业中一种先进的灌溉施药方法。本文详细地描述了在实验室内开展的滴灌施用除草剂-阿特拉津在土壤中运移的物理模拟实验，介绍了采用批量平衡技术和批培养方法获得阿特拉津在供试土壤中吸附特性参数和降解速率常数的实验步骤，给出了根据Freundlich吸附等温线和一级动力学方程对实验数据的拟合结果。此外，由土壤干容重及吸管法求得的土壤质地，利用土壤传递函数间接求取了van Genuchten型水力学参数，并由易混合置换实验得到了溶质运移的弥散度。本文的研究成果为进一步开展滴灌施用阿特拉律在土壤中运移规律的数值分析奠定了基础。