Large-scale tracer profiles in a deep claystone formation (Opalinus Clay at Mont Russelin, Switzerland): Implications for solute transport processes and transport properties of the rock

Single-well hydrogeophysical approaches have previously been applied to several fractured aquifers in the US and the UK, including karstic carbonate systems, in order to characterise solute transport. These approaches typically use single well hydraulic or tracer tests coupled with image or calliper logs to identify and characterise flowing features.&#160; They have variously been used to estimate fracture/conduit aperture and porosity, permeability and/or groundwater velocities, in order to determine groundwater vulnerability or delineate wellhead protection areas. &#160;Here, we outline a new workflow for application & analysis of single-well dilution tests for characterisation of fractured and karstic aquifers, and apply this to the Cretaceous Chalk aquifer, Yorkshire, UK.Chalk aquifers typically have transmissivity that derives essentially from a well-developed network of fractures with solutionally-enhanced apertures and small conduits. Such features can lead to high groundwater velocities and high impacts of contamination on water quality. Knowledge of their solute transport properties is therefore important for delineating source protection areas, characterising contaminant fate and transport, determination of the effectiveness of aquifer remediation, and parameter estimation for models. In this work, single well dilution test data were used to characterise flow patterns in wells and infer properties such as the kinematic fracture porosity, and groundwater velocities. The single-well dilution technique relies on the interpretation of specific electrical conductance (SEC) contrasts between aquifer formation fluid and well fluid column following introduction of saline tracer in the well. Our workflow used both uniform injection (tracer introduced throughout the water column) and point injection (specific depth) tests in open wells under ambient flow conditions. &#160;This workflow allowed sections of well showing horizontal versus vertical flow to be distinguished, and the magnitude of such flows and exchanges with the aquifer to be determined.&#160; Flow within wells are then used to characterise aquifer properties as follows i) presence and direction of vertical hydraulic gradients ii) relative permeability and depth distribution of flowing features iii) in combination with hydraulic test data (e.g. overall well transmissivity) and geophysical logs, the porosity and permeability of the flowing features at each depth iv) in combination with local hydraulic head measurements in nearby wells, an estimate of groundwater velocities in the surrounding aquifer. We tested predicted fracture porosities and groundwater velocities against those measured in previous studies via large scale pumping tests and ambient flow well-to-well tracer tests.&#160; The comparison suggests that the open-well dilution approach can provide reliable flowing porosities and groundwater velocities in fractured aquifer systems.

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tran-SAS v1.0: a numerical model to compute catchment-scale hydrologic transport using StorAge Selection functions

Geoscientific Model Development ◽

10.5194/gmd-11-1627-2018 ◽

2018 ◽

Vol 11 (4) ◽

pp. 1627-1639 ◽

Cited By ~ 8

Author(s):

Paolo Benettin ◽

Enrico Bertuzzo

Keyword(s):

Solute Transport ◽

Large Scale ◽

Solute Concentration ◽

Transport Processes ◽

Catchment Scale ◽

Numerical Accuracy ◽

Hydrological System ◽

The One ◽

Integrated Response ◽

Programming Knowledge

Abstract. This paper presents the “tran-SAS” package, which includes a set of codes to model solute transport and water residence times through a hydrological system. The model is based on a catchment-scale approach that aims at reproducing the integrated response of the system at one of its outlets. The codes are implemented in MATLAB and are meant to be easy to edit, so that users with minimal programming knowledge can adapt them to the desired application. The problem of large-scale solute transport has both theoretical and practical implications. On the one side, the ability to represent the ensemble of water flow trajectories through a heterogeneous system helps unraveling streamflow generation processes and allows us to make inferences on plant–water interactions. On the other side, transport models are a practical tool that can be used to estimate the persistence of solutes in the environment. The core of the package is based on the implementation of an age master equation (ME), which is solved using general StorAge Selection (SAS) functions. The age ME is first converted into a set of ordinary differential equations, each addressing the transport of an individual precipitation input through the catchment, and then it is discretized using an explicit numerical scheme. Results show that the implementation is efficient and allows the model to run in short times. The numerical accuracy is critically evaluated and it is shown to be satisfactory in most cases of hydrologic interest. Additionally, a higher-order implementation is provided within the package to evaluate and, if necessary, to improve the numerical accuracy of the results. The codes can be used to model streamflow age and solute concentration, but a number of additional outputs can be obtained by editing the codes to further advance the ability to understand and model catchment transport processes.

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tran-SAS v1.0: a numerical model to compute catchment-scale hydrologic transport using StorAge Selection functions

10.5194/gmd-2017-305 ◽

2018 ◽

Author(s):

Paolo Benettin ◽

Enrico Bertuzzo

Keyword(s):

Solute Transport ◽

Large Scale ◽

Solute Concentration ◽

Transport Processes ◽

Catchment Scale ◽

Numerical Accuracy ◽

Hydrological System ◽

Practical Tool ◽

Integrated Response ◽

Programming Knowledge

Abstract. This paper presents the tran-SAS package, which includes a set of codes to model solute transport and water residence times through a hydrological system. The model is based on a catchment-scale approach that aims at reproducing the integrated response of the system at one of its outlets. The codes are implemented in MATLAB and are meant to be easy to edit, so that users with minimal programming knowledge can adapt them to the desired application. The problem of large-scale solute transport has both theoretical and practical implications. On one side, the ability to represent the ensemble of water flow trajectories through a heterogeneous system helps unraveling streamflow generation processes and allows making inferences on plant-water interactions. On the other side, transport models are a practical tool that can be used to estimate the persistence of solutes in the environment. The core of the package is based on the implementation of an age Master Equation (ME), which is solved using general StorAge Selection (SAS) functions. The age ME is first converted into a set of ordinary differential equations, each addressing the transport of an individual precipitation input through the catchment, and then it is discretized using an explicit numerical scheme. Results show that the implementation is efficient and allows the model to run in short times. The numerical accuracy is critically evaluated and it is shown to be satisfactory in most cases of hydrologic interest. Additionally, a higher-order implementation is provided within the package to evaluate and, if necessary, to improve the numerical accuracy of the results. The codes can be used to model streamflow age and solute concentration, but a number of additional outputs can be obtained by editing the codes to further advance the ability to understand and model catchment transport processes.

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Claudin Tight Junction Proteins: Novel Aspects in Paracellular Transport

Peritoneal Dialysis International ◽

10.1177/089686080802800605 ◽

2008 ◽

Vol 28 (6) ◽

pp. 577-584 ◽

Cited By ~ 32

Author(s):

Constanze Will ◽

Michael Fromm ◽

Dominik Müller

Keyword(s):

Tight Junction ◽

Solute Transport ◽

Molecular Mechanisms ◽

Family Members ◽

Transport Processes ◽

Paracellular Transport ◽

Solute Flux ◽

Solute Fluxes ◽

Essential Components ◽

Renal Tubular

Claudins are essential components of the intercellular tight junction and major determinants of paracellular solute fluxes across epithelia and endothelia. Many members of this family display a distinct charge or size specificity, whereas others render the epithelium impermeable to transport. Due to intercellular localization, claudin-mediated transport processes are passive and driven by an electrochemical gradient. In epithelial tissues, claudins exhibit a temporal–spatial expression pattern corresponding with regional and local solute transport profiles. Whereas paracellular transport mechanisms in organs such as intestine and kidney have been extensively investigated, little is known about the molecular mechanisms determining solute transport in the peritoneum, and thus the determinants of peritoneal dialysis. Given the ubiquitous expression of claudins in endothelia and epithelia, it is predictable that claudins also contribute to pore formation and determination in the peritoneum, and that they are involved in solute flux. Therefore, we review the basic characteristics of claudin family members and their function as exemplified in renal tubular transport and give an outlook to what extent claudin family members might be of importance for solute reabsorption across the peritoneal membrane.

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Evaluation of the atmospheric transport in a GCM using radon measurements: sensitivity to cumulus convection parameterization

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-2811-2008 ◽

2008 ◽

Vol 8 (10) ◽

pp. 2811-2832 ◽

Cited By ~ 51

Author(s):

K. Zhang ◽

H. Wan ◽

M. Zhang ◽

B. Wang

Keyword(s):

Vertical Distribution ◽

Radon Concentration ◽

Large Scale ◽

Atmospheric Transport ◽

Surface Concentration ◽

Transport Processes ◽

Cumulus Convection ◽

Models Comparison ◽

Convection Schemes ◽

Convection Parameterization

Abstract. The radioactive species radon (222Rn) has long been used as a test tracer for the numerical simulation of large scale transport processes. In this study, radon transport experiments are carried out using an atmospheric GCM with a finite-difference dynamical core, the van Leer type FFSL advection algorithm, and two state-of-the-art cumulus convection parameterization schemes. Measurements of surface concentration and vertical distribution of radon collected from the literature are used as references in model evaluation. The simulated radon concentrations using both convection schemes turn out to be consistent with earlier studies with many other models. Comparison with measurements indicates that at the locations where significant seasonal variations are observed in reality, the model can reproduce both the monthly mean surface radon concentration and the annual cycle quite well. At those sites where the seasonal variation is not large, the model is able to give a correct magnitude of the annual mean. In East Asia, where radon simulations are rarely reported in the literature, detailed analysis shows that our results compare reasonably well with the observations. The most evident changes caused by the use of a different convection scheme are found in the vertical distribution of the tracer. The scheme associated with weaker upward transport gives higher radon concentration up to about 6 km above the surface, and lower values in higher altitudes. In the lower part of the atmosphere results from this scheme does not agree as well with the measurements as the other scheme. Differences from 6 km to the model top are even larger, although we are not yet able to tell which simulation is better due to the lack of observations at such high altitudes.

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Measurement of flow velocity profiles in tank structures using the prototype device OCM Pro LR

Water Science & Technology ◽

10.2166/wst.2011.173 ◽

2011 ◽

Vol 64 (1) ◽

pp. 263-270 ◽

Cited By ~ 2

Author(s):

K. Klepiszewski ◽

M. Teufel ◽

S. Seiffert ◽

E. Henry

Keyword(s):

Flow Velocity ◽

Large Scale ◽

Fluid Dynamic ◽

Waste Water Treatment ◽

Transport Processes ◽

Treatment Efficiency ◽

Cleaning Efficiency ◽

Cfd Modelling ◽

Ultrasonic Signals ◽

Cfd Models

Generally, studies investigating the treatment efficiency of tank structures for storm water or waste water treatment observe pollutant flows in connection with conditions of hydraulic loading. Further investigations evaluate internal processes in tank structures using computational fluid dynamic (CFD) modelling or lab scale tests. As flow paths inside of tank structures have a considerable influence on the treatment efficiency, flow velocity profile (FVP) measurements can provide a possibility to calibrate CFD models and contribute to a better understanding of pollutant transport processes in these structures. This study focuses on tests carried out with the prototype FVP measurement device OCM Pro LR by NIVUS in a sedimentation tank with combined sewer overflow (CSO) situated in Petange, Luxembourg. The OCM Pro LR measurement system analyses the echo of ultrasonic signals of different flow depths to get a detailed FVP. A comparison of flow velocity measured by OCM Pro LR with a vane measurement showed good conformity. The FVPs measured by OCM Pro LR point out shortcut flows within the tank structure during CSO events, which could cause a reduction of the cleaning efficiency of the structure. The results prove the applicability of FVP measurements in large-scale structures.

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Transport Phenomena and Properties in Treelike Networks

Applied Mechanics Reviews ◽

10.1115/1.4033966 ◽

2016 ◽

Vol 68 (4) ◽

Cited By ~ 47

Author(s):

Peng Xu ◽

Agus Pulung Sasmito ◽

Boming Yu ◽

Arun Sadashiv Mujumdar

Keyword(s):

Transport Properties ◽

Scaling Laws ◽

Transport Phenomena ◽

Transport Processes ◽

Research Progress ◽

Transport Systems ◽

Transport Mechanisms ◽

Branching Structures ◽

Flow And Heat Transfer ◽

Flow Heat

Treelike structures abound in natural as well as man-made transport systems, which have fascinated multidisciplinary researchers to study the transport phenomena and properties and understand the transport mechanisms of treelike structures for decades. The fluid flow and heat transfer in treelike networks have received an increasing attention over the past decade as the highly efficient transport processes observed in natural treelike structures can provide useful hints for optimal solutions to many engineering and industrial problems. This review paper attempts to present the background and research progress made in recent years on the transport phenomenon in treelike networks as well as technological applications of treelike structures. The subtopics included are optimization of branching structures, scaling laws of treelike networks, and transport properties for laminar flow, turbulent flow, heat conduction, and heat convection in treelike networks. Analytical expressions for the effective transport properties have been derived based on deterministic treelike networks, and the effect of branching parameters on the transport properties of treelike networks has also been discussed. Furthermore, numerical simulation results for treelike microchannel networks are presented as well. The proposed transport properties may be beneficial to understand the transport mechanisms of branching structures and promote the applications of treelike networks in engineering and industry.

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