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SIMULATION ON SOLUTE TRANSPORT IN FRACTURED ROCKS BASED ON FRACTAL THEORY
基于分形理论的裂隙岩体地下水溶质运移模拟

Wang Jinguo,Zhou Zhifang,
王锦国
,周志芳

岩石力学与工程学报 , 2004,
Abstract: Rough fracture surface is of characteristics of fractal and can be considered as congruence of the upper and lower fracture surfaces. The rough fracture surface and the distribution of fracture apertures can be simulated by fractal theory. The simulation is made on solute transport in rough fractures by characteristic FEM based on the fracture face and fracture apertures simulated by using fractal theory. The result of simulation shows that it is more actual to simulate solute transport in fractures with its roughness considered. In contrast with the solute transport in smooth fractures with average aperture,the frontal surface of concentration in a rough fracture is more behindhand and is of characteristics of nonuniformity and anisotropy.
SIMULATION OF SOLUTE TRANSPORT IN SOILS--THEORY AND APPLICATION
土壤中溶质运移模拟的理论与应用

Xu Xiuyuan,Chen Tongbin,
许秀元
,陈同斌

地理研究 , 1998,
Abstract: The transport and distribution of dissolved chemicals are influenced by water movement in the soil system. In order to understand the advances in underground water pollution, salt transport in salt affected soils and salt accumulation in coast soils affected by seawaters, the studies of the past 2 decades on the theoretical development and practical applications of solute transport simulation in soil water systems are reviewed. The theories and numerical simulations on dispersions, adsorption, uptake and transport of solutes in unsaturated and saturated soils are discussed in the presented paper.
Solute transport predicts scaling of surface reaction rates in porous media: Applications to silicate weathering  [PDF]
Allen G. Hunt,Thomas E. Skinner,Behzad Ghanbarian
Physics , 2013,
Abstract: We apply our theory of conservative solute transport, based on concepts from percolation theory, directly and without modification to reactive solute transport. This theory has previously been shown to predict the observed range of dispersivity values for conservative solute transport over ten orders of magnitude of length scale. We now show that the temporal dependence derived for the solute velocity accurately predicts the time-dependence for the weathering of silicate minerals over nine orders of magnitude of time scale, while its predicted length dependence agrees with data obtained for reaction rates over five orders of magnitude of length scale. In both cases, it is possible to unify lab and field results. Thus, net reaction rates appear to be limited by solute transport velocities. We suggest the possible relevance of our results to landscape evolution of the earth's terrestrial surface.
Physiological Interpretation of Solute Transport Parameters for Peritoneal Dialysis  [PDF]
Jacek Waniewski
Computational and Mathematical Methods in Medicine , 2001, DOI: 10.1080/10273660108833073
Abstract: A mathematical model for solute distribution within the tissue due to combined processes of diffusion and convective transport through the tissue, through the capillary wall, and by lymphatic absorption, during the exchange of the solute between an organ and external medium is applied for the description of the transport of small, middle and macro — molecules. The analytical solutions of the transport equations for the steady state are described. A parameter that characterizes the concentration profiles, the penetration depth, for combined diffusive and convective transport through the tissue is described as a function of the penetration depths for pure diffusive and pure convective transport components. The equation for the solute transport across the tissue surface is similar to a phenomenological formula widely used for the description of clinical and experimental peritoneal dwell studies. The phenomenological transport parameters may therefore be interpreted using the local transport coefficients for the tissue, the capillary wall, and lymphatic absorption. Theoretical estimations of those parameters are in good agreement with clinical data about solute transport in patients on continuous ambulatory peritoneal dialysis.
The theory and experiment of solute migration caused by excited state absorptions

Jin Xiao,Wang Yu-Xiao,Shui Min,Li Chang-Wei,Yang Jun-Yi,Zhang Xue-Ru,Yang Kun,Song Ying-Lin,

中国物理 B , 2010,
Abstract: Nonsymmetrical transition from reverse-saturable absorption (RSA) to saturable absorption (SA) caused by excited state absorption induced mass transport of the CuPcTs dissolved in dimethyl sulfoxide is observed in an open aperture Z-scan experiment with a 21-ps laser pulse. The nonsymmetrical transition from RSA to SA is ascribed neither to saturation of excited state absorption nor to thermal induced mass transport, the so-called Soret effect. In our consideration, strong nonlinear absorption causes the rapid accumulation of the non-uniform kinetic energy of the solute molecules. The non-uniform kinetic field in turn causes the migration of the solute molecules. Additionally, an energy-gradient-induced mass transport theory is presented to interpret the experimental results, and the theoretical calculations are also taken to fit our experimental results.
Reactive solute transport in physically and chemically heterogeneous porous media with multimodal reactive mineral facies: The Lagrangian approach  [PDF]
Mohamad Reza Soltanian,Robert Ritzi,Zhenxue Dai,Chaocheng Huang
Physics , 2014,
Abstract: Physical and chemical heterogeneities have a large impact on reactive transport in porous media. Examples of heterogeneous attributes affecting reactive mass transport are the hydraulic conductivity (K), and the equilibrium sorption distribution coefficient (Kd). This paper uses the Deng et al. (2013) conceptual model for multimodal reactive mineral facies and a Lagrangian-based stochastic theory in order to analyze the reactive solute dispersion in three-dimensional anisotropic heterogeneous porous media with hierarchical organization of reactive minerals. An example based on real field data is used to illustrate the time evolution trends of reactive solute dispersion. The results show that the correlation between the hydraulic conductivity and the equilibrium sorption distribution coefficient does have a significant effect on reactive solute dispersion. The anisotropy ratio does not have a significant effect on reactive solute dispersion. Furthermore, through a sensitivity analysis we investigate the impact of changing the mean, variance, and integral scale of K and Kd on reactive solute dispersion.
An experimental evaluation of the solute transport volume in biodegraded municipal solid waste  [PDF]
H. Rosqvist,D. Bendz
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 1999,
Abstract: A large undisturbed sample (3.5 m3) of 22-year-old, biodegraded solid waste set up to estimate the volume fraction participating in the transport of solutes through the waste material. Altogether, five tracer tests were performed under ponding and sprinkling conditions, and under steady-state and transient conditions. The experimental break through curves (BTCs), which indicated a non-equilibrium transport of the solute by early peaks and long right-hand tails, were used to parameterize log-normal solute travel time probability density functions. The expected solute travel times (i.e. the median solute travel times) were assessed and the corresponding fraction of the experimental volumes active in the transport of solutes was estimated. The solute transport volume fractions defined by the median solute travel times were estimated to vary between 5 and 10% of the total experimental volume. Further, the magnitudes of the solute transport volume fractions defined by the modal (peak) solute travel times were estimated to vary between 1 and 2% of the total experimental volume. In addition, possible boundary effects in terms of rapid flow along the wall of the experimental column were investigated.
A molecular theory of large-solute diffusion  [cached]
A.Yoshimori
Condensed Matter Physics , 2007,
Abstract: The limit of a large solute in the molecular theory of diffusion developed by Yamaguchi et al. [Yamaguchi T. et al., J. Chem. Phys., 2005, 123, 034504] is studied. By the limit, the Stokes approximation to the hydrodynamic equations is derived in the outside region of a diffusing solute. The limit of a large solute also leads to equations in the inside region of the solute. The analytical solution of the inside equation allows one to derive the boundary condition, which is needed on the surface of the solute when the hydrodynamic equations are calculated. The boundary condition includes stick and slip boundary conditions employed by the Stokes law, in the special case. Besides stick and slip conditions, other conditions can be expressed. The boundary condition depends on properties of a solvent.
Cellular automaton model of precipitation/dissolution coupled with solute transport  [PDF]
T. Karapiperis
Physics , 1995, DOI: 10.1007/BF02179974
Abstract: Precipitation/dissolution reactions coupled with solute transport are modelled as a cellular automaton in which solute molecules perform a random walk on a regular lattice and react according to a local probabilistic rule. Stationary solid particles dissolve with a certain probability and, provided solid is already present or the solution is saturated, solute particles have a probability to precipitate. In our simulation of the dissolution of a solid block inside uniformly flowing water we obtain solid precipitation downstream from the original solid edge, in contrast to the standard reaction-transport equations. The observed effect is the result of fluctuations in solute density and diminishes when we average over a larger ensemble. The additional precipitation of solid is accompanied by a substantial reduction in the relatively small solute concentration. The model is appropriate for the study of the r\^ole of intrinsic fluctuations in the presence of reaction thresholds and can be employed to investigate porosity changes associated with the carbonation of cement.
Modelling of Solute Transport from Single Soil Aggregate  [PDF]
A.A. Siyal,A. G. Siyal,Z. A . Abro
Journal of Applied Sciences , 2002,
Abstract: A numerical solution of solute transport from a single spherical aggregate when subject to different leaching techniques is presented in this paper. Theoretical calculations of leaching with different techniques showed that with rest periods (pure salt diffusion periods) equal to on periods (water application periods) water saving equal to 50% were possible with Intermittent Leaching (IL) when compared with Continuous Leaching (CL). However, water savings with IL increased rest periods such that during leaching by increased duration of rest periods to twice of the on periods water savings up to 66% were calculated. Calculations revealed that saturated IL was more water use efficient than that of drained (empty macropores) IL.
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