Narrow Results

The interaction between the H₂ molecule and the PdAg, PdAu, PtAg and PtAu bimetallic dimers deposited on the MgO(100) surface is investigated using density functional theory (DFT). The bimetallic dimers, whose molecular axes are considered to be perpendicular to the support surface, are adsorbed on top of an oxygen atom. Within this adsorption mode, the dimers prefer the orientation in which their Pd or Pt end is closer to the oxygen atom. The Ag and Au ends of the MgO-supported dimers capture the H₂ molecule with small exoenergetic effects. The spontaneous dissociation of H₂ on these ends does not occur. Thus, the MgO support decreases the ability of the dimers to adsorb and dissociate the H₂ molecule. From a catalytic viewpoint, it means that the activity of small bimetallic clusters toward the dissociative adsorption of H₂ is reduced when they are arranged on MgO. On the other hand, the results of our calculations show that the presence of the MgO support strengthens the binding of H atoms inside the PdAu, PtAg and PtAu dimers.

The effect of MgO on structure and dielectric properties of aluminoborosilicate glasses was investigated. FTIR data indicated that glass network was mainly built by tetrahedral [SiO₄], [BO₄], [AlO₄] and trigonal [BO₃]. A small amount of AlO₅ or AlO₆ units also existed. The glass system was characterized with lower dielectric constant (4.17 ~ 4.6) and dielectric loss (12.3 × 10^-4 ~ 14.77 × 10^-4) at 1 MHz. With the increase of MgO content, the quantity of AlO₅ or AlO₆ units decreased. The variation of density showed a decreasing tendency. The dielectric constant and loss were all found to decrease.

Metallic fluids like CuO, Al₂O₃, ZnO, SiO₂ and TiO₂ nanofluids were widely used for the development of working fluids in flat plate heat pipes except magnesium oxide (MgO). So, we initiate our idea to use MgO nanofluids in flat plate heat pipe as a working fluid material. MgO nanopowders were synthesized by wet chemical method. Solid state characterizations of synthesized nanopowders were carried out by Ultraviolet Spectroscopy (UV), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques. Synthesized nanopowders were prepared as nanofluids by adding water and as well as water/ethylene glycol as a binary mixture. Thermal conductivity measurements of prepared nanofluids were studied using transient hot-wire apparatus. Response surface methodology based on the Box–Behnken design was implemented to investigate the influence of temperature (30–60${}^{\circ }$C), particle fraction (1.5–4.5 vol.%), and solution pH (4–12) of nanofluids as the independent variables. A total of 17 experiments were accomplished for the construction of second-order polynomial equations for target output. All the influential factors, their mutual effects and their quadratic terms were statistically validated by analysis of variance (ANOVA). The optimum stability and thermal conductivity of MgO nanofluids with various temperature, volume fraction and solution pH were predicted and compared with experimental results. The results revealed that increase in particle fraction and pH of MgO nanofluids at certain points would increase thermal conductivity and become stable at nominal temperature.

Pulsed laser ablation in liquid (PLAL) of metallic magnesium was used in this work to manufacture magnesium nanoparticles with varying average sizes (10–90nm). (2.07–3.44) $\times$ 10⁸W/cm² of laser intensity and pulse rates of 100 pulses were used to create the nanoparticles. Laser power increased the number of nanoparticles in magnesium oxide (MgO) at 204nm absorption spectroscopic absorbance linearly. When the UV–Vis absorbance of nanoparticles rose, so did their colloidal density (measured in mg/mL). Nanoparticles are more likely to be produced at higher laser scanning rates: UV–Vis absorbance and nanoparticle diameters. Field emission scanning electron microscopy (FESEM) revealed that nanoparticles created dendritic patterns when put upon metal foil. The nanoparticles were measured using dynamic light scattering. When MgO particles were used in antibacterial activity against (in vitro) various gram-positive and gram-negative strains of bacteria, they had a demonstrable impact on some strains of bacteria. MgO has been shown to have antibacterial properties.