Ternary-hybrid nanofluids: significance of suction and dual-stretching on three-dimensional flow of water conveying nanoparticles with various shapes and densities

Increasing knowledge of hybrid nanofluid can be traced to its unique improvement of thermal performance and enhancement of heat transfer rate as applicable in the dynamics of fuel and coolant in automobiles. However, the case of water-based nanofluid conveying three kinds of nanoparticles (i.e., ternary-hybrid nanofluid) with various shapes and densities is far-fetched. The transport phenomena of water conveying smaller densities nanoparticles (i.e., copper nanotubes, graphene, and aluminum oxide) and substantial large densities of nanoparticles (i.e., copper oxide, copper, and silver) of various types through a rectangular closed domain with major emphasis on the significance of suction and dual stretching was investigated. The dimensional equation that model the aforementioned transport phenomenon, for the two cases, were non-dimenzionalized using appropriate similarity variables, parameterized, and solved numerically using shooting techniques together with fourth-order Runge-Kutta integration scheme and in-built bvp4c package of MATLAB. Enhancement in suction and stretching ratio causes the vertical velocity of the motion along x-direction and Nusselt number to be an increasing function. Due to an increase in suction and stretching ratio, fluid flow along (x, y)-directions, temperature distribution, and the local skin friction coefficients are decreasing functions. At all the levels of suction and stretching ratio, higher Nusselt numbers were found in the case of water conveying Copper oxide, Copper, and Silver nanoparticles due to their heavy densities.

Electron Beam Induced Enhancement of the Catalytic Properties of Ion-Track Membranes Supported Copper Nanotubes in the Reaction of the P-Nitrophenol Reduction

This study considers the effect of various doses of electron irradiation on the crystal structure and properties of composite catalysts based on polyethylene terephthalate track-etched membranes and copper nanotubes. Copper nanotubes were obtained by electroless template synthesis and irradiated with electrons with 3.8 MeV energy in the dose range of 100–250 kGy in increments of 50 kGy. The original and irradiated samples of composites were investigated by X-ray diffraction technique (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The improved catalytic activity of composite membranes with copper nanotubes was demonstrated by the example of the reduction reaction of p-nitrophenol in the presence of sodium borohydride. Irradiation with electrons at doses of 100 and 150 kGy led to reaction rate constant increases by 35 and 59%, respectively, compared to the non-irradiated sample. This enhancing catalytic activity could be attributed to the changing of the crystallite size of copper, as well as the surface roughness of the composite membrane.