(Ba<Subscript>0.93</Subscript>Nd<Subscript>0.07</Subscript>)TiO<Subscript>3</Subscript> thin films prepared by sol–gel method as a potential dielectric resonator antenna application

In this paper, we report the application of Neodymium (Nd) doped barium titanate thin films (Ba_1-xNd_x) TiO₃ with x = 0 and 0.07 as dielectric resonator antenna. The films were prepared using the sol–gel method and dip-coating technique. Barium acetate, titanium (IV) isopropoxide and neodymium (III) acetate hydrate were used as precursors while glacial acetic acid and acetylacetone were used as solvents. Si wafers were used as a substrate with dipping times varying from 10, 30, and 50 s. The 0.07 films were >800 nm thick and crystallized after being annealed at 800°C for 30 min. The films were tested as dielectric resonator antenna. It was found that, on the actual antenna circuit, the resonant frequency decreased as the (Ba_0.93Nd_0.07) TiO₃ films thickness increased (from 0.8379, to 5.4525 μm). All samples resonate in the range of 8.68–8.83 GHz with quasi omni-directional radiation patterns.     

Effect of Hall current on MHD mixed convection boundary layer flow over a stretched vertical flat plate

In this paper, the steady magnetohydrodynamic (MHD) mixed convection boundary layer flow of an incompressible, viscous and electrically conducting fluid over a stretching vertical flat plate is theoretically investigated with Hall effects taken into account. The governing equations are solved numerically using an implicit finite-difference scheme known as the Keller-box method. The effects of the magnetic parameter, the Hall parameter and the buoyancy parameter on the velocity profiles, the cross flow velocity profiles and the temperature profiles are presented graphically and discussed. Investigated results indicate that the Hall effect on the temperature is small, and the magnetic field and Hall currents produce opposite effects on the shear stress and the heat transfer at the stretching surface.     

Experimental study of the effect of slotted blades on the Savonius wind turbine performance

This study investigates the effect of Reynolds number on the performance of Savonius wind turbine with slotted blades. The turbine performance investigation was based on the torque coefficient( Ct), power coefficient( Cp), and tip speed ratio( TSR). The experiment used two number of blade configuration, blade overlap ratio of 10%, 12.5% and 20%, slotted position of 15%, 20%, 25% and 35%, and also slotted gap width of 3 mm, 5 mm, 7 mm, and 9 mm. The wind speed carried out in this experiment are 5.94 m/s, 6.46 m/s, 6.99 m/s, and 7.27 m/s, which are generated from the fan blowers as a wind source. The Savonius turbine with 10% overlap ratio shows the best performance. The highest Cp obtained is 0.138 by the variation of a 3 mm gap with Re of 1.44 × 10~4 and 0.526 TSR.     

Synthesis,X-ray structural characterization and pyrolysis studies of heterobi- and heterotrimetallic molecular complexes

Heterobi- and heterotrimetallic complexes [NiTl(acac)₂(dmae)]₂(1) and [Ba(acac)(OH₂)Ni₂(acac)₄Tl(dmae)₂] (2) (acac = acetylacetonate, dmae = N, N-dimethyl aminoethanolate) have been synthesized by simple reactions of Ni(II) acetylacetonate, Tl(I) acetylacetonate and dmaeH for (1) and Ni(II) acetylacetonate, Tl(I) acetylacetonate, Ba metal and dmaeH for (2) in toluene to obtain crystalline products that were characterized by physicochemical and spectroscopic methods. Single-crystal X-ray analysis of both complexes shows that they crystallize in a monoclinic crystal system with space group P2₁/c. TGA studies of the complexes indicate that complex (1) is a suitable precursor for the preparation of composite NiO/Tl₂O₃, while complex (2) yields an unstable composite NiO/Tl₂O₃/BaO which on exposure to air is converted to NiO/Tl₂O₃/BaCO₃ by the absorption of atmospheric carbon dioxide.     

Melting heat transfer in hybrid nanofluid flow along a moving surface

Journal of Thermal Analysis and Calorimetry - The impact and capability of Cu–Al $$_2$$ O $$_3$$ /water nanoliquid as the heat transfer fluid are numerically investigated along a moving...     

Temperature, salt and solvent effects on intramolecular general base-catalyzed methanolysis of ionized phenyl salicylate (PS?)

The kinetic characteristics of CO, HC and NO_x reaction on different kinds of three way catalysts (TWC) has been investigated by using a fixed bed reactor. It was concluded that the three-way reaction on noble metal catalysts is controlled by internal diffusion at high space velocity 16×10⁴ h^–1. On non-noble metal catalysts internal diffusion control prevails at space velocities (S.V.) <4×10⁴ h^–1 and kinetic control occurs at S.V.> 4×10⁴ h^–1. On non-noble metal catalysts containing a small amount of a noble metal, the kinetic control region of the three-way reaction shifts to higher space velocity.     

Thermal behaviors and mechanical properties of halloysite nanotube-reinforced poly(lactic acid) nanocomposites

Poly(lactic acid)/halloysite nanotubes (PLA/HNTs) nanocomposites were prepared using melt compounding followed by compression molding. N,N′-ethylenebis(stearamide) (EBS) was used to improve the dispersion of HNTs and toughen the PLA nanocomposites. The thermal properties of PLA/HNTs nanocomposites were assessed by using differential scanning calorimeter and thermogravimetric analyzer (TG). The TG measurements were performed at both nitrogen and oxygen atmosphere. The mechanical properties of PLA/HNTs were characterized through tensile and impact tests. The morphological properties of the PLA/HNTs nanocomposites were investigated by using transmission electron microscopy and field emission scanning electron microscopy. The degree of crystallinity of PLA nanocomposites was increased slightly by the addition of EBS. The decomposition process of PLA/HNTs depends on the atmosphere reaction during TG test as well as the amount of EBS. The best mechanical properties of PLA/HNTs nanocomposites expressed by the impact strength and elongation at break were achieved by the addition of 5 mass% of EBS.