Mohammed Trari

This paper investigates air–water two-phase flow regimes in a horizontal T-junction mini-channel with a 1 × 1 mm² main mini-channel and a 0.3 × 0.3 mm² side channel. The resulting cross-sectional area ratio of about 11:1 lies outside the range covered by most previous studies. Two injection configurations were compared systematically: in the first, air flows through the main channel and water enters through the side branch; in the second, the two ports are swapped. In the first configuration, the gas superficial velocity ranged from J_g = 1.7 × 10⁻³ to 1.5 m/s and the liquid superficial velocity from J_ℓ = 2.7 × 10⁻³ to 0.1 m/s. In the second, J_g ranged from 1.5 × 10⁻² to 12.5 m/s and J_ℓ from 1.7 × 10⁻³ to 0.28 m/s. Six flow regimes were identified: monodispersed bubbles, slug–bubbles, slug–bubble–-slug, slug, wavy annular and annular flow. From these observations, flow maps were built for each configuration: one in terms of the superficial velocities J_g and J_ℓ and one in terms of the momentum flux ratio X_M and the gas Weber number We_g. The maps show that the flow pattern is strongly sensitive to the injection mode, and that the transition boundaries deviate substantially from those of maps in literature. The set of regimes itself also depends on the configuration. Slug–bubble–slug and annular flows occur only in the first configuration, whereas monodispersed bubbles, slug–bubbles and wavy annular flow occur only in the second. Slug flow is the only regime common to both. For instance, direct visual observation at identical flow rates confirms that the injection configuration alone determines the resulting flow pattern. To the best of our knowledge, such a configuration-dependent set of regimes has not been reported before for this geometry.

Tandem perovskite solar cells offer significant potential for achieving high power conversion efficiencies. Using Solar Cell Capacitance Simulator-1D (SCAPS-1D) numerical simulations, several device architectures were designed and optimized in terms of band gaps, layer thicknesses, doping concentrations, and defect densities. The FTO/TiO₂/MAPbI₃/Spiro-OMeTAD/Au cell achieved a PCE of 43.30% (V_oc = 1.5766 V, J_sc = 30.20 mA/cm², F_F = 90.92%). The AZO/ZnO/MAPbI₃/CIGS/Au configuration reached 36.21%, while the AZO/ZnO/MASnI₃/CIGS/Au device delivered 35.51% efficiency. The best performance was obtained for the FTO/ZnO/MASnI₃/CuSCN/Au structure, with a record simulated PCE of 43.71% (V_oc = 1.4389 V, J_sc = 36.64 mA/cm², FF = 85.25%). The exceptional efficiency is attributed to the synergistic combination of optimal band alignment, low defect density, and appropriate doping conditions. Nonetheless, these simulated values surpass current experimental efficiencies of Sn-based perovskites, emphasizing the gap between idealized models and practical realizations. This work provides clear guidelines for functional layer engineering and underscores the need for experimental validation to bridge this gap. The proposed ZnO/MASnI₃/CuSCN tandem design represents a promising route toward efficient, stable, and lead-free perovskite solar cells.

This study focuses on the synthesis of CuAl₂O₄ nanostructures by the sol-gel method under atmospheric air. The obtained sample underwent several experimental analysis and characterizations. The X-ray diffraction confirms the development of a pure spinel CuAl₂O₄ structure, with an average crystallite size of 24 nm. The microstrain shows that CuAl₂O₄ is subjected to compressive stress (ε < 0), with a slight deformation of the lattice. Furthermore, the fourier transform infrared spectroscopy confirmed the presence of Cu–O and Al–O bonds. Scanning electron microscopy (SEM) analysis showed irregular nanocubes randomly dispersed with sizes ranging from 0.14 to 0.30 µm. The diffuse reflectance revealed an energy gap of 1.98 eV, with a light absorption capacity in the visible region. Electrochemical measurements in Na₂SO₄ allowed the estimation of the flat band potential of CuAl₂O₄ (+0.23 V vs. SCE), Saturated Calomel Electrode (VCE). The photocatalytic activity of the spinel is tested on the degradation of tartrazine (E102) under visible light. A high efficiency in the removal of 95% of tartrazine (Tart, 20 mg/L) in acidic medium, in the presence of CuAl₂O₄ (1 g/L) under visible irradiation for 180 min.

This study aimed to evaluate the effectiveness of the Metal‐Organic Framework 5 (MOF‐5) in efficiently removing Methyl Orange (MO) from wastewater by photocatalysis. MOF‐5 was synthesized by a faster and environmentally friendly route. The crystal structure of MOF‐5 was confirmed by SEM analysis, whose size ranges from 5 to 45 nm. Diffuse reflectance UV/Vis spectroscopy exhibits an optical gap (E _g ) of 3.55 eV, indirectly allowed. The photo‐degradation kinetics show significant removal at low concentrations and decrease at high concentrations (> 50 mg L ⁻¹ ). Finally, the optimization of photo‐degradation by combining six parameters. A Plackett‐Burman Design (PBD) was used to identify the important factors influencing the MO adsorption on MOF‐5, three factors have a significant effect on the adsorption process, namely MO concentration, catalyst dosage Solide/Liquid (S/L) ratio and S ₂ O ₈ ²⁻ (PS) optimized by using the Box‐Behnken Design (BBD) and Response Surface Method (RSM). The maximum photo‐degradation rate for MO removal on MOFS‐5 reached 97.8% and was optimized for a catalyst dose (S/L = 0.465 g/L), MO concentration of 56.67 g/L and S ₂ O ₈ ²⁻ amount of 4.93 mM.