Natural convection and fluid flow in inclined enclosure with a corner heater

The phenomena of natural convection in an inclined square enclosure heated via corner heater have been studied numerically. Finite difference method is used for solving momentum and energy equations in the form of stream function–vorticity. One wall of the enclosure is isothermal but its temperature is colder than that of heaters while the remaining walls are adiabatic. The numerical procedure adopted in this analysis yields consistent performance over a wide range of parameters; Rayleigh number, Ra (10³ ? Ra ? 10⁶); Prandtl number, Pr (0.07 ? Pr ? 70); dimensionless lengths of heater in x and y directions (0.25 ? hx ? 0.75, 0.25 ? hy ? 0.75); and inclination angle, ? (0° ? ? ? 270°). It is observed that heat transfer is maximum or minimum depending on the inclination angle and depending on the length of the corner heaters. The effect of Prandtl number on mean Nusselt number is more significant for Pr < 1.     

Effect of boronizing and shot peening in ferrous based FeCu–Graphite powder metallurgy material on wear,microstructure and mechanical properties

Ferrous based materials manufactured by powder metallurgy (P/M) method are widely used in industry. These materials are very important because they do not require machining, have self-lubricated properties as journal bearing material, find applications in medical industry. In this study, powder metal parts were manufactured from ferrous based FeCu–Graphite composites by P/M method. Wear and mechanical test samples were manufactured and boronizing and boronizing + shot peening was applied to samples. Wear properties of these parts were investigated by wearing at 17 N load and 50 rpm on pin-on-disc wear test rig under dry conditions. Moreover, mechanical properties of powder parts were investigated in detail.     

Capacitive properties of promising energy storage material based on thiophene containing perylenediimide polymer

In this study, electropolymerization of pre-synthesized N,N′-di-[3-[2-(3-thienyl)ethyl] phenyl] perylene-3,4,9,10-bis(dicarboximide) (ThPDITh) was performed on Au button electrode and the properties of the resultant polymer P(ThPDITh) were investigated by electrochemical techniques. Effect of the polymerization charge on the redox behaviors of the polymer film was investigated by cyclic voltammetry (CV) and the polymer film was further characterized by electrochemical impedance spectroscopy (EIS) measurements. Corresponding electrical equivalent circuit was applied to the experimental data to explain the electrochemical phenomenon on the interface of the Au/P(ThPDITh). In order to obtain information on the energy storage properties of P(ThPDITh) as a pseudo-capacitive electrode material, important cell characteristics, such as redox process in anodic and cathodic potential ranges, stability of galvanostatic charge–discharge (GCD) curves, coulombic efficiency, capacitance, energy and power density values were determined. Capacitance values, obtained through different measurements (CV, EIS and GCD) are all in good agreement with each other. All the results suggested that P(ThPDITh) is capable of undergoing multiple reversible redox processes, and a good candidate for improving the capacitance and energy density of electrode material while still offering high power capability.