Employing response surface methodology and neural network to accurately model thermal conductivity of TiO2–water nanofluid using experimental data

In this research, the thermal conductivity of the H₂O–titania nanofluid is modeled versus the particle concentration and temperature via the Artificial Neural Network (ANN) and Response Surface Methodology (RSM). The experimental data include six particle concentrations and five temperatures from 30 to 70 °C. The thermal conductivity augments by the increment in nanoparticle concentration and temperature, such that the maximum thermal conductivity increment happens at the highest temperature and nanoparticle concentration (i.e., T = 70 °C and φ = 1%). It is observed that the impact of temperature on the thermal conductivity is more noticeable than the influence of particle concentration, however, the thermal conductivity demonstrates a more non-linear trend versus nanoparticle volume fraction compared with the temperature. The best structure of the neural network has 2 hidden layers with 2 and 4 neurons, respectively in the 1^st and 2^nd hidden layers. The results show that the prediction precision of the ANN correlation is better than that of the RSM correlation.     

A concise and simple click reaction catalyzed by immobilized Cu(I) in an ionic liquid leading to the synthesis of β-hydroxy triazoles

This study describes an ecocompatible, concise, and practically reliable approach for the regioselective synthesis of β-hydroxy triazoles via Huisgen's click coupling reaction among varied epoxides, NaN₃, and suitable acetylenes catalysed by immobilized Cu(I) in ionic liquid (IL). This one-pot, atom-economic, efficient, and highly regioselective green protocol ensures higher yield of β-hydroxy triazole scaffolds (85–95%). To make the process ecofriendly, this study emphasizes on the catalyst immobilization technique along with its possible recycling that gave a high reaction yield in up to three runs. The structures of all synthesized compounds have been characterized by comparing ¹H nuclear magnetic resonance (NMR), ¹³C NMR, and mass spectroscopic data with those reported in the literature.     

Methylviologen cation radiacal,its dimer and complex in various media

Chemical, photochemical and radiolytic reduction of methylviologen, MV²⁺ (1,1'-dimethyl-4,4' -dipiridinum) leads to the formation of methylviologen cation radical, MV ^+.. It is stable in aprotic solvents, dry polymer foils and frozen aqueous solutions. In the presence of water at ambient temperatures MV^+. can undergo oxidation or conversion into dimer (MV^+.)₂ and/or complex MV^+. (MV²⁺). Upon freezing or addition of neutral salt, MV^+. forms dimers in diluted MV²⁺ solutions (below 0.01 mol dm^-3) while in concentrated ones (exceeding 0.05 mol dm^-3) the formation of the complex prevails. Spectral and E.S.R. characteristics of MV^+., its dimer and complex are given.