University of Gafsa

The importance of this work lies in the application of a combined electrocoagulation/electro-Fenton (EC/EF) treatment for carwash wastewater, offering a cost-effective and efficient remediation approach. During electro-coagulation (EC), experiments were carried out in a cylindrical cell containing 450 mL of carwash wastewater. This process promotes the formation of $$Fe\left( {OH} \right)_{n}$$ (n = 2 or 3) as coagulants, along with $${\text{Fe}}^{3 + } {\text{/Fe}}^{2 + }$$ ions acting as catalysts. The effects of key operating parameters, including applied current, electrode material (Fe and Al), and initial pH, were evaluated, and both COD removal and energy consumption were assessed. In the EF stage, comparative trials were performed in stirred reactors equipped with a Pt anode and a carbon-felt cathode under O₂ bubbling to generate H₂O₂ at the cathode. The hydroxyl radicals produced at the anode surface through water oxidation and in the bulk solution via Fenton’s reagent (Fe2⁺/H₂O₂) promote the oxidative degradation of organic contaminants. The effects of the supporting electrolyte, applied current and the catalytic activity were investigated to optimize electro-Fenton efficiency. Under optimal EC conditions (I = 1 A, Fe electrode, pH = 5.7), 76.58% COD removal was achieved with an energy consumption of 0.987 kWh·m⁻3. Nearly complete COD removal (97.8%) was obtained using the combined process, where residual organics after EC were removed during electro-Fenton treatment at 0.3 A for 360 min.

Introduction. The machine-converter system is a prevalent and essential configuration, widely used not only in variable-speed industrial drive applications, but also in high-tech transportation and power fields. Problem. Conventional drive systems, particularly those supplied by standard 2-level inverters, face major challenges regarding the enhancement of their dynamic performance and drive availability. To overcome these limitations, a solution involves utilizing the open-end stator winding induction machine associated with cascaded 2-level inverter topologies. The goal of this work is to improve the availability of the drive system by increasing its degrees of freedom through the association of an open-end winding induction machine by two cascaded 2-level inverters. Methodology. The mathematical modeling of this machine is presented and validated using MATLAB/Simulink. To evaluate the machine’s performance, it is first powered by two cascaded 2-level inverters and subsequently by three cascaded 2-level inverters. Following this initial evaluation, the machine is then fed by two cascaded 2-level inverters operating in degraded mode. This analysis features different failure configurations, and the specific operational conditions that must be respected. Results. This topology enhances dynamic performances and enables effective power segmentation as well as a degraded mode operation. These benefits are confirmed by the simulation results. The scientific novelty is based on demonstrating the effectiveness of degraded mode control, which gives the machine-cascaded inverters topology a superior advantage in terms of reliability and performances. Practical value. This topology provides a highly reliable and fault-tolerant drive solution, ensuring better performance during normal operation and better availability after an inverter failure. References 15, tables 1, figures 24.

UDC 512.5 We provide and study a Hom-type generalization of Jordan–Malcev–Poisson algebras called Hom–Jordan–Malcev–Poisson algebras. We show that they are closed under twisting by suitable self-maps and give a characterization of admissible Hom–Jordan–Malcev–Poisson algebras. In addition, we introduce the notion of pseudo-Euclidian Hom–Jordan–Malcev–Poisson algebras and describe its $T^*$-extension. Finally, we generalize the notion of Lie–Jordan–Poisson triple system to the Hom setting and establish its relationships with Hom–Jordan–Malcev–Poisson algebras.

This study presents a multifunctional nanocomposite based on poly(vinylidene fluoride) (PVDF) for applications in energy harvesting and sensing. We hereby report the synthesis of advanced nanocomposites that incorporate varying concentrations of barium titanate (BaTiO 3 ) nanoparticles and multi-walled carbon nanotubes (CNTs) through an optimized solution processing method. The fabricated composites achieve intrinsic piezoelectric properties without the requirement for external poling. The synergistic effects of BaTiO 3 (10–20 wt%) and CNT (0–1.5 wt%) concentrations were revealed using a concentration-resolved design matrix in which CNT loading was systematically varied within each BaTiO 3 level. The resulting composition-property relationships were comprehensively investigated through multi-scale characterization, including morphological, mechanical, and electrical analyses. The developed PVDF-based nanocomposite exhibits pronounced mechanical reinforcement, with Young’s modulus and tensile strength increased by 68% and 79%, respectively, relative to pure PVDF. The optimized nanocomposite delivers superior piezoelectric performance, achieving a d 33 of 66 pC/N and generating an open-circuit voltage of 25 V with a maximum output power of 345 μ W. Simultaneously, it exhibits an exceptional piezoresistive sensitivity of 20.6 kPa −1 , enabling dual-mode operation for high-performance energy harvesting and pressure sensing. By co-optimizing energy harvesting and sensing within a single multifunctional nanocomposite, this work provides a foundational platform for autonomous systems, enabling the development of next-generation smart skins and self-powered electronics. • First concentration-resolved map linking formulation to function for BaTiO 3 -CNT co-filled PVDF. • Dual fillers drive self-poling and percolation, giving electroactive β -phase of 95 %. • ∼ 40 µm PVDF/BaTiO 3 /CNT films made without external poling or stretching. • Tenfold voltage gain up to 25 V and power output to 345 µW under cyclic loading. • High-sensitivity pressure sensing: 20.6 kPa −1 (66.8 k Ω / kPa ) with < 1 % hysteresis.

In this work, we investigated the dielectric behaviorof an anthracene-containingpoly­(p-arylene-ethynylene)-alt-poly­(p-arylene-vinylene) (AnE-PVad) copolymer blended with fullerene(PCBM). The study was carried out in an organic solar cell structureof ITO/PEDOT:PSS/AnE-PVad:PCBM/LiF/Al using impedance spectroscopy.The real part of the complex impedance (Z′)reached high values at low frequencies. This behavior is consistentwith space-charge accumulation and interfacial polarization causedby charge buildup in the bulk and at the electrode interfaces. Athigher frequencies, dipoles aligned more effectively with the alternatingfield, which reduced the impedance. The Cole–Cole plots showedclear semicircular arcs that correspond to different relaxation processesand conduction mechanisms. These features were successfully interpretedusing an equivalent circuit model. The dielectric constant (ε′)displayed strong dispersion at low frequencies due to Maxwell–Wagnerinterfacial polarization. The dielectric loss (ε″) decreasedsharply below approximately 104 rad·s–1, reflecting dipolar deformation and relaxation effects. Analysisof the complex electric modulus offered further insight into charge-transportdynamics and space-charge relaxation within the active layer. Thereal part of the modulus (M′) increased markedlywith angular frequency, indicating a shift from electrode-dominatedto bulk-controlled conduction. The impedance and dielectric analysesshow that the electrical response of the AnE-PVad:PCBM solar cellis governed by interfacial polarization and field-dependent relaxationmechanisms. These findings provide a deeper understanding of chargedynamics in organic photovoltaic systems.

This paper develops an enhanced current control approach for a Three-Phase Four-Wire (3P4W) split-capacitor Shunt Active Power Filter (SAPF) to mitigate current harmonics produced by Compact Fluorescent Lamps (CFLs). A Fuzzy Hysteresis Current Controller (FHCC) and a Modulated Hysteresis Current Controller (MHCC) are proposed to provide the triggering signals for the Insulated-Gate Bipolar Transistors (IGBTs) of the SAPF to ensure improved switching performance and reduced steady-state error near the Shifted Zero-Crossing Area (S-ZCA). The Synchronous Reference Frame (SRF) power theory is adopted for reference current generation. The effectiveness of both techniques, FHCC and MHCC, is evaluated through simulations inMATLAB<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup>/Simulink and validated in real time using the Hardware-in-the-Loop (HIL) platform, especially with the Typhoon HIL-402 device. As both techniques act exclusively for switching gate signal generation techniques and not reference-current extraction methods, the structures are general in nature and are not load-dependent. Comparative analysis with the conventional hysteresis current controller (HCC) demonstrates significant improvements in the reduction of Total Harmonic Distortion (THD) to 1.08% and the overall improvement of power quality without notches in waveforms near zero crossings. The results confirm the robustness and efficiency of the proposed MHCC strategy in the HIL implementation.

Organic–inorganic hybrid materials based on divalent metal halides constitute versatile platforms for tuning their physicochemical properties, with potential applications in optoelectronics, energy storage, and dielectric devices. Here, we present the first synthesis and complete characterization of [(C4H9)4N]2CoBr4, a novel halogenocobaltate(ii) compound. Hirshfeld surface analysis and single-crystal X-ray diffraction reveal a monoclinic structure composed of layered tetrabutylammonium cations and tetrahedral [CoBr4]2− units stabilized by strong C–H⋯Br interactions. The integrity of the organic and inorganic components is verified by vibrational spectroscopy (FT-IR and Raman). DSC analysis revealed the existence of two phase transitions at 335 K and 345 K. Electrical and dielectric tests, performed between 313 K and 353 K, demonstrated a phase transition around T = 338 K, as well as non-Debye relaxation processes, thermally activated charge transport, and semiconducting properties. At low frequencies, the dielectric permittivity reaches exceptionally high values (ε′ ≈ 105), highlighting the strong dielectric response of this material and its potential relevance for functional dielectric and energy-storage applications. This study expands the family of functional halogenocobaltates(ii) and provides valuable insights into the structure–property relationships that govern hybrid materials.