Effect of metal oxide nanofluids on the performance of passive solar still single slope for two different absorbent plates

This study aims to improve the performances of a solar still single slope using metal oxide nanofluid (Al₂O₃–water, Cu₂O–water, and TiO₂–water). The numerical study was carried out for the climatic conditions of Agadir, Morocco, with different concentrations of nanofluids inside a basin equipped with an absorber plate with two different absorptivities. The numerical study is based on thermal balance equations applied on different solar system components and solved using the Runge Kutta method. The numerical model is validated by comparing our results with the literature available data. A comparison study of the effect of these nanofluids on solar still productivity is done. The results show that the productivity of the solar still using nanoparticles Cu₂O, TiO₂, and Al₂O₃ are 7.38, 7.1, and 7.064 kg m⁻² day⁻¹, respectively. It is obtained that the maximum efficiency of the solar still is found to be 55.27% by using cuprous oxide nanoparticles. Furthermore, an enhancement in solar still productivity of 6.36%, 19.54%, and 33.25% is obtained by dispersing 1%, 3%, and 5% volume fraction of Cu₂O nanoparticles in pure water, respectively compared to the conventional solar. Moreover, the impact of the absorptivity of the absorber plate on the solar still effectiveness is investigated. Two types of coatings are considered to change the absorber plate absorptivity. The results indicate that the efficiencies of the solar system are 58.81% and 51.77% using an absorber plate with 0.95 and 0.85 of absorptivity, respectively.     

Synergistic effect of iodide ions and bark resin of Schinus molle for the corrosion inhibition of API5L X70 pipeline steel in H2SO4

The synergistic effect of bark resin of Schinus molle (BRSM) and iodide ions in 0.5 M sulfuric acid has been studied for the first time by potentiodynamic polarization and electrochemical impedance spectroscopy measurements; also, the surface morphology has been analyzed by scanning electron microscopy–energy-dispersive X-ray spectroscopic analysis in the present work. The results show that the BRSM and iodide ions have an evident synergistic inhibition effect in a 0.5-M sulfuric acid solution. The adsorption of the BRSM/iodide ion system follows the Langmuir adsorption isotherm and acts as a mixed-type inhibitor in sulfuric acid. The BRSM/iodide ion system is an effective inhibitor for API5L X70 pipeline steel in the 0.5-M sulfuric acid solution. The maximum percentage inhibition efficiency is equal to 99% at 1 g/L BRSM + 2 mM KI.     

A comparative study of phenols composition,antioxidant, and antifungal potency of leaves extract from five Moroccan Vitis vinifera L. varieties

Vitis vinifera (L) crops, covers an area of about 54,000 ha corresponding to a production of 230,000 t of grapes, representing 5.5% of the national perennial corps. However, this plant is sensitive to various ravages and diseases, among others, the cryptogrammic by fungi. The degrading enzymes of the cell wall are among the factors of pathogenicity the more important than fungi use to colonize their host plants. In this study, the first step was devoted to the antioxidant activity and phenols composition (phenylalanine-ammonia-lyase [PAL], tyrosine-ammonia-lyase [TAL], flavonoids, and tannins) as well as high-performance liquid chromatography analysis in five vineyard leaves extract, which are “Superior, Early sweet and Flame” (Allochthonous), “Abbou and Adari” (endemic). In the second step, the lytic activities “pectinase, polygalacturonase, xylanase, mannanase, glucanase, and cellulase” were investigated among six epiphytic fungus to compare their hydrolytic aggressiveness. Subsequently, as a third part, phenols antifungal potency and Trichoderma biocontrol were displayed in the study. The phenolic compounds observed in the attributes leaves were different among varieties (p < .05), and show that the endemic variety “Abbou” leads the phytochemical amount, which has the highest quantities of PAL, and TAL, as well as the DPPH and FRAP antioxidant activity, while the introduced variety show a higher amount in total phenol and flavonoids. The polygalacturonase, mannanase, and pectinase activities are probably the main factors responsible for the aggressiveness of the studied fungus. Phenols potency showed a good mycelial inhibition with 82.09% as compared to the biocontrol (64.45%). Given the efficacy of the phytochemical control in this study, the phenols could be a part of integrated management strategies for sustainable control of vineyard disease.     

An exploration of corrosion inhibition of mild steel in sulphuric acid solution through experimental study and Monte Carlo simulations

Abstract

4-[4-(1H-imidazol-1-yl)methyl)-1H-1,2,3-triazol-1-yl]methylbenzophenone (ITBP) and 4[4-(1H-1,2,4-triazol-1-yl)methyl)-1H-1,2,3-triazol-1-yl]methylbenzophenone (TTBP) are synthesized as new heterocyclic compounds of the triazole derivative family and tested successfully as potential inhibitors for MS in 1?M H₂SO₄ corrosive medium by using gravimetric analysis, electrochemical impedance spectroscopy, potentiodynamic polarization, and energy dispersive X-ray spectroscopy (EDX). Polarization curves show that the tested inhibitors are mixed-type inhibitors. Scanning electron microscopy (SEM) affirmed the existence of an adsorbed film on the steel surface. Monte Carlo simulations were in excellent agreement with the experimental tests.

Abbreviation: PDP: Potentiodynamic Polarization; EIS: Electrochemical impedance spectroscopy; DFT: Density functional theory; MC: Monte Carlo     

Ultrasonic Inspection of the Setting Mechanism of Glass Ionomer Cement

Russian Journal of Nondestructive Testing - Ultrasonic measurements were used to characterize the setting process of glass-ionomer dental cement (GIC) and to evaluate the effect of temperature on...     

Optimization of printing parameters for improvement of mechanical and thermal performances of 3D printed poly(ether ether ketone) parts

Many processing parameters can be adjusted to optimize the fused filament fabrication (FFF) process, a popular and widely used additive manufacturing techniques for plastic materials. Among those easily adjusted parameters are the nozzle temperature, printing speed, raster orientation, and layer thicknesses. Using poly(ether ether ketone) (PEEK) as the base material, a design of experiments analysis was performed on the main FFF parameters. A response surface methodology was applied to analyze the results and to maximize the output responses. Results have shown that the nozzle temperature is the most influential parameter on tensile properties and the crystallinity degree of printed PEEK by FFF process. Parts produced with optimized FFF parameters were then subjected to an annealing treatment to induce a relaxation of residual stress and to enhance crystallinity. The best properties for 3D printed PEEK parts were achieved with annealed parts prepared at 400°C with a printing speed of 30 mm/s, 0.15 mm layer thickness and raster orientation of [0°/15°/−15°]. The resulting parts have mechanical properties comparable to those of injected PEEK.     

Full and reduced-order H∞ filtering of Takagi–Sugeno fuzzy time-varying delay systems: Input–output approach

This article addresses the issue of delay-dependent H_∞ filtering design for TakagiŮSugeno fuzzy time-varying delay systems using the input–output approach. A three-term approximation model has been used to transform the original system into two interconnected subsystems. Since the nonquadratic Lyapunov–Krasovskii functional requires to deal with the membership function's (MF) time derivative, upper-bound inequalities have been added to the obtained conditions. Based on the scaled small gain theorem, nonquadratic Lyapunov–Krasovskii functional approach and considering the bounds of the MF time-derivative, the H_∞ full- and reduced-order filters are designed and then formulated in terms of linear matrix inequalities. Finally, illustrative examples are presented to demonstrate the validity of the proposed methods.     

Copper‐Catalyzed Asymmetric Conjugate Addition of Dimethylzinc to Acyl‐N‐methylimidazole Michael Acceptors: Scope,Limitations and Iterative Reactions

An efficient copper‐catalyzed enantioselective conjugate addition of dimethylzinc to unsaturated 2‐acyl‐N‐methylimidazoles has been achieved using a chiral bidentate hydroxyalkyl‐NHC ligand. The reactions proceed with excellent regioselectivity (1,4 vs. 1,6 and 1,8) in extended conjugated systems to afford the 1,4‐adducts in high enantioselectivities. This regioselectivity could be ascertained by DFT studies highlighting the crucial role of the imidazole ring. Thanks to the development of efficient protocols to regenerate the unsaturated 2‐acyl‐N‐methylimidazole moiety, an iterative process has been developed ultimately leading to 3,5,7 all‐syn or anti‐anti polydeoxypropionate stereodiads.

     

Effect of thermal insulation using leather and carpentry wastes on thermal comfort and energy consumption in a residential building

In this work, we investigate the effect of the thermal insulation by leather wastes (wet-blue chrome shavings and buffing dust) and carpentry wastes (wood shavings and sawdust) on the energy consumption of a model building using the average climatic data of the city of Casablanca (Morocco). For this study, we used the dynamic thermal simulation tool “TRNSYS 16” which predicts the thermal behavior of building and systems associated with it. Using this software, we evaluated the effect of the above material wastes on thermal comfort and building energy consumption. The type and the thickness of the materials were considered as variants to choose the better solution. The average temperatures of building supposed thermally insulated compared to those obtained without insulation clearly show the thermal insulation ability of tested materials during the cold and warm periods of the year. Increasing the thickness of the insulator makes locals increasingly comfortable. Because of their performance, leather and carpentry wastes can compete with conventional insulating materials such as polystyrene and cork.     

Structure of the ion-rich phase in DVB cross-linked graft-copolymer proton-exchange membranes

We report on correlations between the proton conductivity, the water swelling and the dry-state morphology of ETFE-g-poly(sulfonated styrene-co-DVB) proton-exchange membranes (PEMs). We focus on the influence of the systematically varied monomer composition. Especially, the impact of the DVB cross-linker on the ion-rich phase aggregated in the dry PEM is studied by small-angle X-ray scattering. A modified hard-sphere fluid model describing the ion-rich phase is applied to interpret the observed scattering function. We find hereby that the size and number density of the ion-rich domains decrease with increasing cross-link level. Consequently, the distance between the ion-rich domains is proportional to the cross-link level. The total volume fraction of water in the hydrated membrane is proportional to the overall volume fraction of the ion-rich phase, and the number of water molecules per ion-rich aggregate is inversely proportional to the level of cross-linking. We show that there is a clear correlation between the structure of the ion-rich phase formed in the dry state and the proton conductivity of the hydrated membrane: beyond a threshold, indicating the onset of percolation of the aqueous network, the conductivity is proportional to the hydration level and inversely proportional to the mean distance between the ion-rich domains.