Conjugate heat transfer is an important area of research which has been in demand due to its applications related to various scientific and engineering fields. The current research is focused to study the heat transfer in a porous medium sandwiched between two solid walls of an annular vertical cylinder. The prime focus of the current study was to evaluate the effect of solid wall thickness, the influence of variable wall thickness at inner and the outer radius, the conductivity ratio and the solid wall conductivity ratio on the heat transfer characteristics of the porous medium. The surface at inner and outer radii of the annulus is maintained isothermally at T h and T ∞ such that T h > T ∞ . The governing partial differential equations for the conjugate heat transfer in porous medium and that of solid walls are converted into a set of algebraic equations with the help of finite element method and then solved simultaneously to predict the temperature variation in the solid wall as well as the porous region of the annular domain. HHeight of cylinder (m)Permeability of the porous medium (m 2 ) KrThermal conductivity ratio = k s1 /k p Kr o Thermal conductivity ratio = k s2 /k p KrsThermal conductivity ratio of two solids k s1 /k s2 N u Average Nusselt number r, z Cylindrical coordinates (m) r , z Non-dimensional coordinates RaRayleigh number RrRadius ratio = (r o − r i )/r i T, TDimensional ( • C) and non-dimensional temperature, respectively u, w Velocity in r and z directions, respectively (m/s)

Autonomous underwater vehicle (AUV) is an unmanned tether-free vehicle which is powered by battery or fuel cell. The weight of the AUV is a major issue to be decided when considering its performance. To manufacture a propeller that is lighter in weight and able to carry the pressure applied to the blades is an involving process. The present study investigates the performance of the propeller of an AUV, manufactured by additive manufacturing, using ABS plastic material. The propeller blade designed in SolidWorks was transferred to the CUBPRO (DUO), followed by setting the parameters for a 3D printing machine. A comparative study was carried out for ABS (Acrylonitrile Butadiene Styrene) material between the required dimensions and a 3D printed model dimension propeller blade. An error analysis was carried out and we observed that ABS material is the most suitable for an AUV propeller. A stress-strain analysis for the propeller was carried out using the Finite Element Method.

Functionalized magnetite nanoparticles (Fe3O4) were prepared using the coprecipitation method followed by functionalization with a multipotent antioxidant (MPAO). The MPAO was synthesized and analyzed using FTIR and NMR techniques. In this study, the functionalized nanoparticles (IONP@AO) were produced and evaluated using the FTIR, XRD, Raman, HRTEM, FESEM, VSM, and EDX techniques. The average determined particle size of IONP@AO was 10 nanometers. In addition, it demonstrated superparamagnetic properties. The magnitude of saturation magnetization value attained was 45 emu g−1. Virtual screenings of the MPAO’s potential bioactivities and safety profile were performed using PASS analysis and ADMET studies before the synthesis step. For the DPPH test, IONP@AO was found to have a four-fold greater ability to scavenge free radicals than unfunctional IONP. The antimicrobial properties of IONP@AO were also demonstrated against a variety of bacteria and fungi. The interaction of developed nanoantioxiants with biomolecules makes it a broad-spectrum candidate in biomedicine and nanomedicine.

The present study is intended to study heat and mass transfer in a vertical annular cylinder embedded with saturated porous medium. The inner surface of cylinder is maintained at uniform wall temperature and uniform wall concentration. The governing partial differential equations are non-dimensionalised and solved by using finite element method (FEM). The porous medium is discritised using triangular elements with uneven element size. Large number of smaller-sized elements are placed near the walls of the annulus to capture the smallest variation in solution parameters. The results are reported for both aiding and opposing flows. The effects of various non-dimensional numbers such as buoyancy ratio, Lewis number, Rayleigh number, aspect ratio, etc on heat and mass transfer are discussed. The temperature and concentration profiles are presented.123 698 I. A. Badruddin et al.

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