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Lattice Boltzmann method (LBM) is employed in the current work to simulate two-phase flows of immiscible fluids over a square obstacle in a 2D computational domain using the Rothman-Keller color gradient model. This model is based on the multiphase Rothman-Keller description, it is used to separate two fluids in flow and to assess its efficacy when treating two fluids in flow over a square obstacle with the objective of reducing turbulence by adjusting the viscosities of the two fluids. This turbulence can cause major problems such as interface tracking techniques in gas-liquid flow and upward or downward co-current flows in pipes. So, the purpose of the study is to replace a single fluid with two fluids of different viscosities by varying these viscosities in order to reduce or completely eliminate the turbulence. The results show that to have stable, parallel and non-overlapping flows behind the obstacle, it is necessary that the difference between the viscosities of the fluids be significant. Also, showing that the increase in the viscosity ratio decreases the time corresponding to the disappearance of the vortices behind the obstacle. The results presented in this work have some general conclusions: For M≥2, the increase in the viscosity difference leads to an increasing of friction between fluids, reducing of average velocity of flow and decreasing the time corresponding to the disappearance of the vortices behind the obstacle. However, for M≤1/2, the opposite occurs.

The objective of this research is to study the fluid flow control allowing the reduction of aerodynamic drag around a square cylinder using two parallel partitions placed downstream of the cylinder using the lattice Boltzmann method with multiple relaxation times (MRT-LBM). In contrast to several existing investigations in the literature that study either the effect of position or the effect of length of a single horizontal or vertical plate, this work presents a numerical study on the effect of Reynolds number (Re), horizontal position (g), vertical position (a), and length (Lp) of the two control partitions. Therefore, this work will be considered as an assembly of several results presented in a single work. Indeed, the Reynolds numbers are selected from 20 to 300, the gap spacing (0 ≤ g ≤ 13), the vertical positions (0 ≤ a ≤ 0.8d), and the lengths of partitions (1d ≤ Lp ≤ 5d). To identify the different changes appearing in the flow and forces, we have conducted in this study a detailed analysis of velocity contours, lift and drag coefficients, and the root-mean-square value of the lift coefficient. The obtained results revealed three different flow regimes as the gap spacing was varied. Namely, the extended body regime for 0 ≤ g ≤ 3.9, the attachment flow regime for 4 ≤ g ≤ 5.5, and the completely developed flow regime for 6 ≤ g ≤ 13. A maximal percentage reduction in drag coefficient equal to 12.5%, is given at the critical gap spacing (gcr = 3.9). Also, at the length of the critical partition (Lpcr = 3d), a Cd reduction percentage of 12.95% was found in comparison with the case without control. Moreover, the position of the optimal partition was found to be equal to 0.8d i.e. one is placed on the top edge of the square cylinder and the second one is placed on the bottom edge. The maximum value of the lift coefficient is reached for a plate length Lp = 2d when the plates are placed at a distance g = 4. On the other hand, this coefficient has almost the same mean value for all spacings between the two plates. Similarly, the root means the square value of the lift coefficient (Clrms) admits zero values for low Reynolds numbers and then increases slightly until it reaches its maximum for Re = 300.

This study aims to valorize saffron by-products and use them as biostimulants in agricultural practices against chemical products. For this, different treatment of the aqueous extract of the stigmas, tepals and stamens: STS = 1 g/L stigma + 1 g/L tepal + 1 g/L stamen, TS = 2 g/L tepal + 0.6 g/L stigma, ST = 1 g/L stigma + 1 g/L tepal, S = 1 g/L stigma, SS = 1 g/L stigma + 1 g/L stamen, T = 2 g/L tepal, are used as foliar treatment, seven times every fortnight during the cycle, in a complete random block, on eggplant plants in greenhouse conditions, to know their effect on plant growth and composition fruit biochemistry. The STS, S, and T treatments significantly (p ≤ 0.05) improved plant height compared to the other treatments and the control. Then, the T and S treatments significantly (p ≤ 0.05) improved the polyphenol contents (flavonols and anthocyanins). In contrast, the highest values are observed in the fruits of the plants receiving the T, S, and ST treatments for the protein content. However, the T and S treatments significantly decreased the ascorbic acid content (p ≤ 0.05). Our results show that using the aqueous extract of tepals at 2 g/L and saffron at 1 g/L can improve the main secondary metabolites of fruits in greenhouse conditions.

Sustainability is becoming increasingly pivotal in the construction industry, prompting a shift toward the use of bio-sourced waste materials. This study presents a novel application of mint stem (MS) waste as an additive in mortar with the aim of harnessing its cellulosic nature to enhance thermal insulation. The mineralogical and chemical properties of the raw materials were examined to understand their inherent characteristics and suitability for mortar composite development. The modified mortars were subjected to thermal and mechanical evaluations with MS proportions up to 6% by cement mass. The hot disk method revealed a substantial reduction in thermal conductivity (over 50%), whereas compressive strength testing indicated a decrease with higher MS content. The water absorption increased slightly, implying changes in porosity. These findings suggest that MS can play a significant role in the development of energy-efficient building materials, despite trade-offs in mechanical strength. This study discusses the implications of these results for sustainable construction and the potential of MS-enhanced mortar. [ABSTRACT FROM AUTHOR]

This study examined the role of social context in the expression of the bilingual cognitive advantage in 145 bilingual university students. All participants mastered Arabic as their native language (L1), but half were highly proficient in French (high L2 group), whereas half were less proficient (low L2 group). A color-word Stroop test with incongruent, congruent and neutral stimuli was administered in single language blocks (Arabic or French words) or in a mixed block (Arabic and French words), either under social presence, or alone. Stroop interference was analyzed to assess the cost of resolving conflict in incongruent trials and was compared across groups and experimental conditions. If bilingualism comes with a cognitive advantage, a reduction of interference in high (vs. low) L2 proficient subjects is to be expected. Analysis revealed that interference was significantly reduced in high L2 group, but only under the single language condition. Furthermore, whereas social context and sex had no main effects, analysis revealed a significant 4-factor interaction between L2 proficiency, linguistic context, social context, and sex. Social presence further reduced interference (social facilitation) in high L2 proficient females, but not in males. Overall, the results suggest that mastering a second language comes with cognitive advantages which adapt dynamically to social and linguistic contexts in a sex-dependent manner. We argue that advancing bilingualism research requires more attention to the social environment.

In this study, the behavior of bubbles and droplets during boiling and condensation processes on a wettable horizontal plate with variable density (qw) is investigated using pseudopotential lattice Boltzmann model for multiphase flow. The analysis focuses on the complete life cycle of bubbles and droplets, from their appearance to their disappearance under the effect of gravity. The main objectives of this study are to analyze the propagation of bubbles or droplets on the horizontal surface (l*) and to study their evolution as a function of time, characterized by h*, for different values of the wetting surface density. To ensure the reliability of our model in simulating these phenomena, the hydrodynamic effect and Laplace's law were. This combination of approaches demonstrated a good compromise between our results and the references, confirming the model's reliability. Furthermore, we present results that showcase the density behaviors for different wetting surfaces, allowing us to analyze droplet behavior on the horizontal plate. It was observed that for large values of qw, significant droplet spreading occurred, and this process took time to subside. Conversely, for small values of qw, spreading was minimal, enabling rapid droplet detachment. Interestingly, in the case of boiling, the observed behaviors were reversed compared to condensation. Moreover, the heat flux analysis for the single-density case provided insights into the temperature behavior around bubbles during the nucleation process and droplets during the droplet condensation process, while maintaining a fixed density value on average. These findings contribute to a better understanding of the thermal dynamics associated with boiling and condensation phenomena. [ABSTRACT FROM AUTHOR]