Entropy analysis in electrical magnetohydrodynamic(MHD) flow of nanofluid with effects of thermal radiation,viscous dissipation,and chemical reaction

The unsteady mixed convection flow of electrical conducting nanofluid and heat transfer due to a permeable linear stretching sheet with the combined effects of an electric field, magnetic field, thermal radiation, viscous dissipation, and chemical reaction have been investigated. A similarity transformation is used to transform the constitutive equations into a system of nonlinear ordinary differential equations.The resultant system of equations is then solved numerically using implicit finite difference method.The velocity, temperature, concentration, entropy generation, and Bejan number are obtained with the dependence of different emerging parameters examined. It is noticed that the velocity is more sensible with high values of electric field and diminished with a magnetic field. The radiative heat transfer and viscous dissipation enhance the heat conduction in the system. Moreover, the impact of mixed convection parameter and Buoyancy ratio parameter on Bejan number profile has reverse effects. A chemical reaction reduced the nanoparticle concentration for higher values.

Adiabatic Decomposition of Two Kinds of Organic Peroxides by Accelerating Rate Calorimeter

The accelerating rate calorimeter was applied to study the thermal hazard of two kinds of organic peroxides, i.e. methyl ethyl ketone peroxide (MEKPO) and benzoyl peroxide (BPO). And their thermal decomposition characteristics were discussed. Meanwhile, thermal decomposition characteristics of MEKPO and BPO vvere compared. The result indicated that MEKPO is more sensitive to thermal effect than BPO. While once the thermal decomposition takes place. BPO will be more hazardous than MEKPO due to its serious pressure effect. Thermal kinetic analysis of these two kinds of organic peroxides was also taken, and the kinetic parameters for them were calculated. The study of thermal decomposition of MEKPO solution with different initial concentrations indicated that, the lower concentration MEKPO solution is, the higher onset temperature will be. And with the addition of organic solvent, it becomes more difficult for MEKPO to reach a thermal decomposition. Therefore, its thermal hazard is reduced.

Thermal and environmental stability of poly(4-ethynyl-p-xylylene-co-p-xylylene) thin films

The aim of this paper was to test the thermal and environmental stability of poly（4-ethynyl-p-xylylene- co-p-xylylene） thin films prepared by chemical vapor deposition （CVD） and to optimize the reaction conditions of the polymer. Fourier transformed infrared spectroscopy （FTIR）, thermogravimetric analysis （TGA） and fluorescence microscopy were employed to investigate the stability of the reactive polymer coatings in various environmental conditions. Chemical reactivity of the thin films were then tested by Huisgen 1,3-dipolar cycloaddition reaction （＂click＂ reaction）. The alkyne functional groups on poly（4- ethynyl-p-xylylene-co-p-xylylene） thin films were found to be stable under ambient storage conditions and thermally stable up to 100 ℃ when annealed at 0.08 Torr in argon. We also optimized the click reaction conditions of azide-functionalized molecules with poly（4-ethynyl-p-xylylene-co-p-xylylene）. The best reaction result was achieved, when copper concentration was 0.5 retool/L, sodium ascorbate concentration to copper concentration was 5：1. In contrast, the azide concentration and temperature had no obvious effect on the surface reaction.