Tracer Transport in a Homogeneous Porous Medium: Experimental Study and Acquisition Data with LabVIEW

This work represent the incorporation of information procurement (DAQ) equipment and programming to acquire information (LabVIEW) as well as real-time transport to show parameter appraises with regard to subsurface stream and transport issues. The main objective is to understand the mechanism of water and solute transfer in a sandy medium and to study the effect of some parameters on the transport of an inert tracer. In order to achieve this objective, a series of experiments were carried out on a soil column equipped with a tensiometer to monitor the state of saturation of the medium and by two four-electrode probes for measuring the electrical conductivity in the porous medium

Morphological effect of dichloromethane on alfalfa (Medicago sativa) cultivated in soil amended with fertilizer manures

In this work, we investigated the morphological effect of dichloromethane (DCM) on alfalfa (Medicago sativa) plant. We studied in vitro the influence of its concentration on alfalfa germination. The plants were placed in pots for 15 weeks, and exposed to increasing concentrations of DCM (50 µg L−1 and 84 mg L−1). In addition, we examined the effect of two manures (cow and sheep), which were applied to a contaminated soil, on alfalfa plant growth. The effect of the presence of dichloromethane is obvious even in plant–soil manure system. In fact, in the event of contamination, the soil–cow manure mixture represents the best setting medium for the Alfalfa plant compared to other environments, regardless of the contamination level. Indeed, the presence of two types of manure does not allow the suppression of the inhibitory effect of dichloromethane on the mass of the dry matter of the aerial part which is 18.38% for the cow manure-amended soil and 13.96% for the sheep manure-amended soil

Adsorption of dye on a Tunisian unsaturated layered soil: physical and numerical modeling

The main objectives of this study is to model the transport of methylene blue (MB) in homogenous and layered soils which has been studied experimentally by fixed bed column. The effect of soil stratification has been studied through numerical investigation based on the coupled solute transport model in three-layered soil. The effect of some significant parameters such as flow rate, initial concentration of MB, thickness of each layer and the numbers of layers on the breakthrough curves have been undertaken. A finite element analysis model was employed to predict the transport of MB in soils. A two dimensional model based on Richards equation and advection-dispersion equation coupled with adsorption model has been developed and an analytical model has been used to predict the dispersivity. The results shows that the soil heterogeneity has a significant effect on methylene blue (MB) adsorption through unsaturated layered media and the effect of the parameters of the upper layer of the soil is more significant than those of the lower layer but this effect can be controlled with the choice of the thicknesses of each layer

Combined effect of unsaturated soil condition and soil heterogeneity on methylene blue adsorption/desorption and transport in fixed bed column: Experimental and modeling analysis

Several series of batch and fixed bed column experiments have been carried out to study the methylene blue sorption and transport in sandy and clay soil under different experimental conditions. The non linear forms of the pseudo-second order kinetic model and the Freundlich and Langmuir isotherm models were used to quantify the maximum adsorption capacity of the used materials. The effects of several experimental factors (flow rate, initial concentration, saturation condition of soil and soil heterogeneity) on the breakthrough curves have been undertaken. Experimental data revealed that the breakthrough curves depend on flow rate, methylene blue inlet concentration, saturation condition of soil and soil heterogeneity. A two dimensional model based on Richards equation and advection–dispersion equation coupled with adsorption model was developed. A comparative analysis between this model and Thomas model showed the effectiveness of advection–dispersion model to describe the experimental breakthrough curves and particularly in an unsaturated heterogeneous medium. The advection dispersion model reproduces perfectly the transfer mechanisms in porous media and seems to be a useful tool to better understanding the physical processes and the effect of capillary barrier of methylene blue transport in unsaturated heterogeneous soil. The result shows also that the soil heterogeneity has a significant effect on methylene blue adsorption through unsaturated layered media. Furthermore, in the interface between two layers with different hydrodynamic proprieties, the adsorption capacity increases with a decrease in kinetic adsorption rate caused by the decrease in pore water velocity

Energy performance based optimization of building envelope containing PCM combined with insulation considering various configurations

Phase change material (PCM) is considered as a promising solution for reducing heating and cooling energy consumption by integrating them into the building envelope, which in turn reduces CO2 emissions. In this paper numerical simulations were carried out to evaluate the energy performance based optimization of envelope building integrated PCM. The effect of several parameters (PCM melting temperature, PCM layer combined with insulation, PCM layer and insulation layer thickness, double PCM layer system in the double external wall, and air layer interaction with PCM in roof) on energy savings in two typical models of residential buildings in Tunisia are investigated. Results show that energy demand reduction of 73.81% and 76.46% can be achieved under the optimal conditions of application of the PCM integrated in simple wall and double wall buildings respectively. This is associated with significant reduction of CO2 emission. Moreover, PCM layer performance is improved by increasing its thickness with an optimal value of 6 cm. Two PCM layers located in the middle of the double wall involve higher energy saving than a simple PCM layer