This paper is dedicated to the numerical simulation of the flow of a liquid over a textured surface. Two cases are considered: the Cassie-Baxter wetting regime, where air is trapped in the cavities (diphasic flow), and the Wenzel wetting regime, where the cavities are filled with fluid (monophasic flow). The simulation results show that the flow over a textured surface is equivalent to a slip flow over a smooth surface. The amount of slip increases with the size of the cavity up to a maximum value, after which it decreases. The Cassie-Baxter wetting regime leads to twice as much slip as in the Wenzel regime. However, an increase in liquid pressure allows the liquid to enter the cavity, leading to a significant reduction in slip. A positive net force can be generated if the surface is partially textured, with fluid pressure generation controlled by the amount of slip.
The escalating threat of antimicrobial resistance (AMR) and the environmental impact of industrial pollutants, particularly synthetic dyes, emphasize the pressing requirement for novel solutions. This study investigates the green synthesis of ZnO/Fe2O3 nanocomposites using Urtica dioica extract with the aim of achieving dual functionality as both antimicrobial agents and photocatalysts for pollutant degradation. The nanocomposites were synthesized with varying loads of Fe2O3 (5-50%) and characterized using X-ray diffraction (XRD) and diffuse reflectance spectroscopy (DRS). XRD analysis confirmed the presence of both the hexagonal wurtzite ZnO phase and the alpha-Fe2O3 hematite phase in all the composites, while DRS analysis revealed that the bandgap energy decreased progressively (from 1.89 to 1.72 eV) as the Fe2O3 content increased. The photocatalytic efficiency of the composites was evaluated by degrading methylene blue (MB), Congo Red (CR) and safranin O (SO) dyes under visible light. This demonstrated that the degradation performance depends on the composition, with the best activity being observed at 5% Fe2O3. Antioxidant activity was assessed using a DPPH center dot free radical scavenging assay. This showed that Urtica dioica extract exhibits superior radical scavenging capacity (maximum inhibition of 38%) compared to ZnO/Fe2O3 nanoparticles (maximum inhibition of 18%). The antibacterial efficacy against Pseudomonas aeruginosa was evaluated using direct confrontation and disk diffusion methods. This revealed that the activity was dose- and light-dependent, with enhanced performance under light exposure (10 mm inhibition zone) compared to dark conditions (1 mm). This study demonstrates the successful green synthesis of biphasic ZnO/Fe2O3 nanocomposites with promising photocatalytic and antimicrobial properties. While the results suggest possible synergistic interactions between the oxides, the underlying mechanisms, including potential charge transfer effects, require further investigation using advanced characterization techniques. Using Urtica dioica extract as a biogenic source provides a promising eco-friendly approach to synthesizing nanomaterials, with potential applications in wastewater treatment and the biomedical field.
Unfilled Co4Sb12 skutterudites typically exhibit n-type conductivity at room temperature due to native donor-type defects associated with off-stoichiometric compositions arising from Sb loss during high-temperature synthesis. Achieving stable p-type conductivity in the absence of rare-earth fillers or transition-metal substitution at the Co site remains a significant challenge. Here, we report an in situ composite engineering approach in which elemental Bi (x = 0, 3, 6, 11 wt.
Quality control of compressed earth construction materials remains a technical challenge, mainly due to the variability of raw materials and the absence of standardized non-destructive evaluation methods. This study proposes an original experimental approach to predict the mechanical performance of compressed earth blocks (CEBs), stabilized with wheat straw, using ultrasonic pulse velocity (UPV) measurements. A total of 120 blocks were manufactured according to an experimental design combining four levels of compaction energy (25, 50, 75, and 100 blows per layer) and five straw contents (0
We extend Petkov & scaron;ek's algorithm for computing hypergeometric solutions of scalar difference equations to the case of difference systems t(Y) = MY, with M E GLn(C(x)), where t is the shift operator. Hypergeometric solutions are solutions of the form gamma P where P E C(x)n and gamma is a hypergeometric term over C(x), i.e. t(gamma)/gamma E C(x). Our contributions concern efficient computation of a set of candidates for t(gamma)/gamma which we write as lambda = c AB with monic A, B E C[x], c E C & lowast;. Factors of the denominators of M-1 and M give candidates for A and B, while another algorithm is needed for c. We use super-reduction algorithm to compute candidates for c, as well as other ingredients to reduce the list of candidates for A/B. To further reduce the number of candidates A/B, we bound the type of A/B by bounding local types. Our algorithm has been implemented in Maple and experiments show that our implementation can handle systems of high dimension, which is useful for factoring operators. (c) 2025 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
