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This study explores the safety problems of hydrogen leakage and explosion in hydrogen fuel cell buses through Computational Fluid Dynamics simulations. The research investigates the diffusion behavior of hydrogen in the passenger cabin depending on the leakage position and flow rates, identifying a stratified, constant-concentration layer formed at the top of the cabin. Leakage near the rear wall of the vehicle provided the highest hydrogen concentration, while at higher flow rates, the diffusive process accelerated the spreading of flammable hydrogen concentrations. Hydrogen ignition simulations showed a fast internal pressure increase and secondary explosions outside the vehicle. Thermal hazards in the cases were higher than overpressure. The research’s additional analysis of ignition timing and source location shows that overpressure peaked initially with delayed ignition but declined afterward, while rear-ignited flames exhibited the farthest high-temperature hazard range at 10.88 m. These findings are fundamental for giving insight into hydrogen behavior in confined spaces and thus guiding risk assessment and emergency response planning for the development of safety protocols in hydrogen fuel cell buses, contributing to the safer implementation of hydrogen energy in public transportation.

Wetlands are ecologically and economically important habitats. In the Mediterranean region, they account for 18.5 (±3.5) million ha or 1.5% of the world’s wetlands. Algeria has 1,500 wetlands, 50 of which are Ramsar sites. One of them is the Macta wetland, a specific ecosystem on the northwestern coast of Algeria. The study aims to provide data on the spatiotemporal evolution and interaction of the Macta wetland with human activities and climate. A diachronic diagnosis for the period 1958–2023 (65 years) was carried out using maps from 1958 and data collected by remote sensing for the period 1972–2023 in a Geographical Information System (GIS). The geomatics approach is based on the use of ArcGIS 10.8 and satellite imagery from Landsat and Sentinel-2. A precise cartography, close to the reality of the terrain, shows that between 1958 and 2023, the agricultural development, the urbanisation and flooding affected 26,515 ha or about half of the total area of the wetland. In 65 years, the anthropogenic pressure is five times greater than that caused by flooding. Therefore, the adaptation of the Macta wetland is an issue that should be considered and solved by the local environmental authorities.

Tetrasubstituted 2-acetylthiophene derivative 5 was synthesized and then condensed with various nitrogen nucleophiles such as 5-amino-1,2,4-triazole, 2-aminobenzimidazole, aniline or p-chloroaniline to afford the corresponding iminothiophene derivatives 6–8a,b. Condensation of thiophene 5 with malononitrile as carbon nucleophile afforded compound 9, which underwent nucleophilic addition with DMF-DMA to afford compound 10. The newly synthesized products were characterized by elemental analysis, IR, MS, 1H-13C-NMR and CHN analysis and then evaluated for their antimicrobial activity. Results of the in vitro antibacterial activity showed that thiophene derivative 7 was found to be more potent than the standard drug gentamicin against Pseudomonas aeruginosa. Some of these compounds showed potential antimicrobial activities. Molecular docking and Osiris/Molinspiration analyses show the crucial role and impact of substituents on bioactivity and indicate the unfavorable structural parameters in actual drug design: more substitution with electronic donor group doesn’t guarantee more effective bioactivity. This study should greatly help in an intelligent and a controlled pharmacomodulation of antibiotics.

Cardiovascular haemodynamics alters during posture changes and exposure to microgravity. Vascular auto-remodelling observed in subjects living in space environment causes them orthostatic intolerance when they return on Earth. In this study we modelled the human haemodynamics with focus on head and neck exposed to different hydrostatic pressures in supine, upright (head-up tilt), head-down tilt position, and microgravity environment by using a well-developed 1D-0D haemodynamic model. The model consists of two parts that simulates the arterial (1D) and brain-venous (0D) vascular tree. The cardiovascular system is built as a network of hydraulic resistances and capacitances to properly model physiological parameters like total peripheral resistance, and to calculate vascular pressure and the related flow rate at any branch of the tree. The model calculated 30.0 mmHg (30%), 7.1 mmHg (78%), 1.7 mmHg (38%) reduction in mean blood pressure, intracranial pressure and central venous pressure after posture change from supine to upright, respectively. The modelled brain drainage outflow percentage from internal jugular veins is 67% and 26% for supine and upright posture, while for head-down tilt and microgravity is 65% and 72%, respectively. The model confirmed the role of peripheral veins in regional blood redistribution during posture change from supine to upright and microgravity environment as hypothesized in literature. The model is able to reproduce the known haemodynamic effects of hydraulic pressure change and weightlessness. It also provides a virtual laboratory to examine the consequence of a wide range of orthostatic stresses on human haemodynamics.

Children’s literature is considered a rich aesthetic choice with various and numerous themes, and a cognitive giving in its diverse forms of literature, culture, knowledge, history, art, and sciences. It enables us to gain social experience that helps us discover and learn possible solutions in real life. Moreover, it embodies exquisite artistic and stylistic experiences, both in form and content, dominated by emotional sentiment,emotional flow, eloquence, delicacy, and sweetness of expression, without exaggeration.

In the current investigation, the efficiency inhibition of two newly synthesized bi-pyrazole derivatives, namely 2,3-bis[(bis((1 H-pyrazol-1-yl) methyl) amino)] pyridine ( Tetra-Pz-Ortho ) and 1,4-bis[(bis((1 H-pyrazol-1-yl) methyl) amino)] benzene ( Tetra-Pz-Para ) for corrosion of carbon steel (C&S) in 1 M HCl medium was evaluated. A Comparative study of inhibitor effect of Tetra-Pz-Ortho and Tetra-Pz-Para was conducted first using weight loss method and EIS (Electrochemical Impedance Spectroscopy) and PDP (Potentiodynamic Polarisation) techniques. Tetra-Pz-Ortho and Tetra-Pz-Para had a maximum inhibition efficacy of 97.2% and 96.2% respectively at optimum concentration 10 −3 mol/L and temperature 303 K, according to the data, suggesting that they are both effective inhibitors. The inhibition effectiveness of Tetra-Pz-Ortho and Tetra-Pz-Para increases significantly with higher concentration but decreases as temperature rises. The adsorption study demonstrated that the two molecules tested follow the Langmuir adsorption isotherm and chemically adsorbed on the metallic surface. The polarization methods showed that both compounds Tetra-Pz-Ortho and Tetra-Pz-Para were classified as mixed inhibitors. Based on the electrochemical impedance technique, the addition of the two inhibitors increased the charge transfer resistance and decreased the double layer capacity. In addition, the scanning electron microscopy (SEM) showed that the surface roughness of the C&S was considerably reduced in the presence of both Tetra-Pz-Ortho and Tetra-Pz-Para compared to its roughness without the inhibitors, indicated that the two inhibitors are effectively absorbed onto the carbon steel surface. These results were supported by elemental analysis of the metal/solution interface using X-ray photoelectron spectroscopy (XPS), for the two molecules tested. All studies demonstrated that the compound Tetra-Pz-Ortho is the most effective inhibitor. The DFT calculations and Monte Carlo/Molecular dynamic (MC/MD) simulations were treated and discussed for both compounds Tetra-Pz-Ortho and Tetra-Pz-Para in order to explain their interfacial approach and compared them to experimental results. The computational results of quantum chemistry were in agreement with those acquired by experimental methods.

Znotraj raziskave spletnih učnih okolij obravnava ta članek štiri modele učenja na daljavo z uporabo platforme OpenMWS znotraj procesov izbire, transkripcije in iskanja s konkordancami za označevanje gradnje in analize video korpusa. Študentje jih uporabljajo za naloge kot ustvarjanje video korpusov nanovo pri zaključevanju diplomskih nalog, pripravništva, skupinskega projektnega dela in s preoblikovanjem obstoječih video korpusov za potrebe novih uporabnikov, kot so osnovnošolci in srednješolci. Članek izpostavlja, kako analitika beleži interakcije študentov s platformo, pristop, ki študente vabi k razmisleku o lastnih učnih poteh.

The RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 is one of the optimum targets for antiviral drug design and development. The hydroxyl groups of cytidine structures were modified with different aliphatic and aromatic groups to obtain 5´- O -acyl and 2´,3´-di- O -acyl derivatives, and then, these derivatives were employed in molecular modeling, antiviral prediction, molecular docking, molecular dynamics, pharmacological and POM studies. Density functional theory (DFT) at the B3LYP/6-31G++ level analyzed biochemical behavior and molecular electrostatic potential (MESP) of the modified cytidine derivatives. The antiviral parameters of the mutated derivatives revealed promising drug properties compared with those of standard antiviral drugs. Molecular docking has determined binding affinities and interactions between the cytidine derivatives and SARS-CoV-2 RdRp. The modified derivatives strongly interacted with prime Pro620 and Lys621 residues. The binding conformation and interactions stability were investigated by 200 ns of molecular dynamics simulations and predicted the compounds to firmly dock inside the RdRp binding pocket. Interestingly, the binding residues of the derivatives were revealed in high equilibrium showing an enhanced binding affinity for the molecules. Intermolecular interactions are dominated by both Van der Waals and electrostatic energies. Finally, the pharmacokinetic characterization of the optimized inhibitors confirmed the safety of derivatives due to their improved kinetic properties. The selected cytidine derivatives can be suggested as potential inhibitors against SARS-CoV-2. The POM Theory supports the hypothesis above by confirming the existence of an antiviral (O δ- —O’ δ- ) pharmacophore site of Hits.

Metakaolin-based geopolymers are aluminosilicate materials that can be used as cationic dye adsorbents in aqueous system treatment. Our aim in this paper is to study the ability of geopolymer powder produced from metakaolin and alkaline activators to act as an adsorbent to remove methylene blue (MB). The solid materials were systematically analyzed by X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared spectrometery (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and the point of zero charge. XRF, FTIR, XRD, SEM, and EDX analyses confirmed the formation of a geopolymer composite by geopolymerization reaction. The influence of various experimental factors such as geopolymer dosage, pH, initial dye concentration, contact time, and temperature was assessed. Adsorption isotherms were evaluated by Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherms. Kinetics data were studied using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The thermodynamic parameters, namely, Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), were determined. The results indicated that the maximum decolorization was found in high pH values. The collected isotherm data were best fitted by the Langmuir isotherm, and the maximum adsorption capacity of dye onto the geopolymer was 43.48 mg/g. The experiment kinetics followed the pseudo-second-order kinetic models. The thermodynamic results demonstrated that the adsorption of the obtained material occurs spontaneously as an endothermic process. The results confirmed that the prepared adsorbent can be used for remediation of water contaminated by MB dye.

In this work, geopolymer synthesized with perlite and an alkaline activator medium was evaluated as a new adsorbent and photocatalyst for degradation of methylene blue (MB) dye from an aqueous medium. The functional group, the structure, and the morphology of the raw and the synthesized materials were characterized using FT-IR, XRD, and SEM analysis. The degradation of MB in the contaminated solution was examined using the spectrophotometric technique. Several analysis methods revealed the formation of the aluminosilicate gel after the geopolymerization reaction. The kinetics data with UV and without UV irradiations were well fitted with the pseudo-second-order equation. The results indicated that the degradation efficiency of cationic dye by perlite-based geopolymer without and with UV was up to 88.94% and 97.87% in 4 hours, respectively. The degradation efficiencies of methylene blue are in the following order: perlite-based geopolymer under UV irradiations is greater than perlite-based geopolymer without UV irradiations that is larger than UV irradiations. The overall experimental results suggested that the new elaborated material with synergetic adsorption and photocatalytic activities has a great potential for the treatment of water contaminated by hazardous substances.