Ricerc@Sapienza

In this study Ni-Co-W alloys have been produced by electrodeposition on Al net. Two electrolytic baths, with and without sodium citrate, having the same metal ion content (20 g/l Ni, 8 g/l Co and W in the range 2-8 g/l) and boric acid content 20 g/l, have been used. Temperature and current density operative conditions have been varied in the range 30-60 degrees C and 260-350 A/m(2) respectively.

In this work, a preliminary numerical model of the behavior of retro-reflective materials used as envelope coatings on street canyon buildings façades has been tested. Retro-reflective materials have a surface finish that allows to reflect the solar radiation back in the same direction of the incident radiation. In the last years this kind of materials has been studied as buildings envelope coating for their potentials in the reduction of the UHI effect.

The magnetohydrodynamic flow and heat transfer of a liquid metal in a channel past a circular cylinder with walls of non-uniform conductivity were investigated. The applied magnetic field was transversal to the forced flow (x-direction) and coplanar with the obstacle, featuring non-null components in both the z- and y-directions. Moreover, the cylinder was displaced by the duct centreline toward the bottom wall and its surface was at uniform temperature, so that a ΔT was present between the obstacle and the fluid at the inlet.

In the design of innovative nanomaterials for electromagnetic (EM) field absorption and shielding a crucial issue is the experimental characterization of the complex effective permittivity of non-uniform layered materials or electrically thin lossy layers. This paper proposes a technique to retrieve the complex relative permittivity of a thin lossy coating supported by a dielectric substrate through transmission/reflection measurements in a rectangular waveguide.

Laminar natural convection of water inside box-shaped enclosures heated at the bottom and cooled at the top, with perfectly insulated sidewalls, is studied numerically with the aim to investigate the enhanced heat transfer effects deriving from the suspension of an adiabatic square honeycomb in the middle of the enclosure so as to leave an upper and a lower clearance allowing for horizontal flows. A computational code based on the SIMPLE-C algorithm is used to solve the system of the mass, momentum and energy transfer governing equations.

Natural convection in water-filled square cavities inclined with respect to gravity, having one wall
cooled at 0°C and the opposite wall heated at a temperature ranging between 4°C and 30°C, is studied
numerically for cavity widths spanning from 0.02 m to 0.1 m in the hypothesis of temperaturedependent
physical properties, with the main aim to determine the optimal tilting angle for maximum
heat transfer. A computational code based on the SIMPLE-C algorithm is used to solve the system of

Nano scale method of lattice Boltzmann is developed to predict the fluid flow and heat transfer of air through the inclined lid driven 2-D cavity while a large heat source is considered inside it. Two case studies are supposed: first one is a pure natural convection at Grashof number from 400 to 4000 000 and second one is a mixed convection at Richardson number from 0.1 to 10 at various cavity inclination angles.

Lattice Boltzmann method ability is improved to simulate the mixed convection of Water / FMWCNT nanofluid inside a two dimensional microchannel. The influences of gravity on hydrodynamic and thermal domains are studied while the microchannel walls are imposed by a constant thermal heat flux at three different case studies as no-gravity, Ri=1 and Ri=10. The flow Reynolds number is chosen as one and the liquid micro flow conditions are involved by B = 0.005, B = 0.01 and B = 0.02. The mass fraction of carbon nanotubes in water are selected as ϕ=0, ϕ=0.1% and ϕ=0.2%.

The fluid flow and heat transfer of a nanofluid is numerically examined in a two dimensional microchannel filled by a porous media. Present nanofluid consists of the functionalized multi-walled carbon nanotubes suspended in water which are enough stable through the base fluid. The homogenous mixture is in the thermal equilibrium which means provide a single phase substance. The porous media is considered as a Darcy- Forchheimer model.

This paper deals with wireless power transfer technology applied to charge the battery of a short-distance electric vehicle. Different compensation topologies (series-series and LCC compensations) are examined and compared in terms of magnetic field emission and system efficiency. The investigation is carried out by simulations and measurements taking into account the variation of the coupling factor due to possible lateral misalignment of the parallel coils, and of the load conditions that depend on the level of the battery charge.