Reddad El Moznine

Safe drinking water remains an issue all around the world, especially in arid countries that require seawater desalination to obtain safe water. This research seeks to analyze water quality at the major stages of an SWRO plant, i.e., raw seawater intake, RO permeate, reject brine, and distribution network water. For the study, conventional physicochemical methods of water quality analysis, as well as electrochemical impedance spectroscopy, were used. Four water samples were taken at different stages of the treatment process: raw seawater (feed water), RO permeate, reject brine, and distribution network water. Physicochemical parameters, such as pH, electrical conductivity, total dissolved solids (TDS), major ions (Na⁺, Cl⁻, Ca²⁺, and Mg²⁺), and heavy metals (Zn, Cu, Cr, and Hg) concentrations, were evaluated. Electrochemical impedance spectroscopy was used to investigate ionic transport, dielectric relaxation, and interfacial polarization mechanisms within the tested solutions. It has been shown that RO membranes are capable of rejecting major ions up to 95–99%, as can be seen in the low values of conductivity and TDS of RO permeate. EIS analysis also allowed for identifying specific electrochemical characteristics of all four types of water, with brine being characterized by the highest polarization rates and relaxation times.

Several studies on solar cells using SCAPS-1D were conducted to investigate their performance, which are typically limited to I–V analysis for DC characterization. Therefore, in the present study, a very wide frequency range from 10^–2 Hz to 10¹² Hz was employed to explore diffusion processes and investigate the performance of lead-free Perovskite Solar Cells (PSCs) featuring as a novel heterostructure. These investigations concern the optimization of MASnI₃ thickness as an absorber. Additionally, the impact of series (Rs) and shunt (Rsh) resistances is also examined. From the I–V analysis, it was determined that the power efficiency (PCE) could be achieved at a thickness of 0.6 µm. Increasing the series resistance (Rs) led to a significant decrease in the fill factor (FF) and (PCE), whereas the shunt resistance (Rsh) demonstrated a notable improvement in both (FF) and (PCE). Analysis of AC characteristics revealed complex impedance (Z*) and modulus (M*) indicative of main ionic transport, recombination, and diffusion processes crucial for optimization. An appropriate equivalent circuit model was developed and validated through deconvolution and theoretical considerations, yielding parameters such as the time constant for each process. It was observed that ionic conductivity and electronic diffusion play key roles in balancing charge collection and recombination losses. The critical influence of series and shunt resistance on low and high-frequency processes was emphasized, underscoring their significance in solar cell efficiency. A strong correlation was established between the evolution of time constants for each process and power conversion efficiency (PCE).

In this work, a sensor yarn based on a natural sisal yarn containing a non-electro-conductive core impregnated with PVA polymer and coated by PEDOT:PSS polymer as an electro-conductive sheath was investigated. The main objectives include the development of this new sensor yarn as a first step. Then, we look towards the insertion of this sensor yarn into different woven structures followed by the monitoring of the mechanical behaviour of composite materials made with these fibrous reinforcements. The combined effect of the structural geometry and the number of PEDOT:PSS coating layers on the properties of the sensor yarns was investigated. It was found that the number of PEDOT:PSS coating layers could strongly influence the electromechanical behaviours of the sensor yarns. Different methods of characterization were employed on strain-sensor yarns with two and four coating layers of PEDOT:PSS. The piezo-resistive strain-sensor properties of these selected coating layers were evaluated. Cyclic stretching-releasing tests were also performed to investigate the dynamic strain-sensing behavior. The obtained results indicated that gauge factor values can be extracted in three strain regions for two and four coating layers, respectively. Moreover, these strain-sensor yarns showed accurate and stable sensor responses under cyclic conditions. Furthers works are in progress to investigate the mechanism behind these first results of these sisal fibre-based sensors.

This work aims to investigate the physical and mechanical properties of sisal fiber and yarn of Moroccan origin. The cellulosic and non-cellulosic constituents of the Moroccan sisal fiber were identified by FTIR spectroscopy. The thermal properties were studied by thermogravimetric analysis. The hydrophilicity of the fiber was evaluated by the contact angle. The results show that the sisal fiber has a low thermal stability. The mechanical properties of the fiber analyzed by the Impregnated Fiber Bundle Test (IFBT) method show that the porosity of the impregnated yarns and the twist angle of the yarns influence the elastic modulus of the sisal fiber. The physical and mechanical properties of the manufactured sisal yarns were also characterized and analyzed. The obtained results reveal an interesting potential to use the Moroccan sisal fiber in development of bio-sourced composite materials.

In this paper we present an inexpensive electronic measurement instrumentationdeveloped in our laboratory, to measure and plot the impedance of a loaded fuel cell orbattery. Impedance measurements were taken by using the load modulation method. Thisinstrumentation has been developed around a VXI system stand which controls electroniccards. Software under Hpvee^® was developed for automatic measurements and the layout ofthe impedance of the fuel cell on load. The measurement environment, like the ambienttemperature, the fuel cell temperature, the level of the hydrogen, etc..., were taken withseveral sensors that enable us to control the measurement. To filter the noise and theinfluence of the 50Hz, we have implemented a synchronous detection which filters in a verynarrow way around the useful signal. The theoretical result obtained by a simulation underPspice^® of the method used consolidates the choice of this method and the possibility ofobtaining correct and exploitable results. The experimental results are preliminary results ona 12V vehicle battery, having an inrush current of 330A and a capacity of 40Ah (impedancemeasurements on a fuel cell are in progress, and will be the subject of a forthcoming paper).The results were plotted at various nominal voltages of the battery (12.7V, 10V, 8V and 5V)and with two imposed currents (0.6A and 4A). The Nyquist diagram resulting from theexperimental data enable us to show an influence of the load of the battery on its internalimpedance. The similitude in the graph form and in order of magnitude of the valuesobtained (both theoretical and practical) enables us to validate our electronic measurementinstrumentation. One of the future uses for this instrumentation is to integrate it with several control sensors, on a vehicle as an embedded system to monitor the degradation of fuel cell membranes.

In this paper we present an electronic measurement instrumentation developed in our laboratory, to measure and plot the impedance of the fuel cell on load. Impedance measurements were taken by using the load modulation method. This instrumentation has been developed around a VXI system stand which controls electronic cards. Software under HPVEEreg was developed for automatic measurements and layout. The theoretical result obtained by a simulation under PSPICEreg consolidates us in the possibility of obtaining correct and exploitable results. The experimental results are preliminary results on a 12 V vehicle battery (Impedance measurements on a PEMFC are in progress). The similitude in the graph form and in order of magnitude of the values obtained (both theoretical and practical) enables us to validate our instrumentation. One of the future uses for this instrumentation is to integrate it on a vehicle as an embedded system to monitor the degradation of fuel cell membranes.