This paper deals with simulations of a radio interface of third generation (3G) mobile systems operating in the WCDMA FDD mode including propagation predictions in macro and microcells. In the radio network planning of 3G mobile systems, the quality of coverage and the system capacity present a common problem. Both macro and microcellular concepts are very important for implementing wireless co...

A new multiple access control (MAC) protocol for mobile wireless communications is presented and investigated. We explore, via an extensive simulation study, the performance of the protocol when integrating voice and data traffic over two wireless channels, one of medium capacity (referring mostly to outdoor microcellular environments) and one of high capacity (referring to an indoor microcellu...

Abstract Supercritical CO 2 -assisted extrusion technique was used to produce flame retarded foams from recycled poly(ethylene terephthalate) (rPET). Synergistic combination of aluminium-alkylphosphinate retardant (FR) and natural montmorillonite (MMT) utilised provide adequate retardancy at moderate loadings, i.e. with less than 9% additives. Addition FR found increase the rate degradation dur...

The mechanism for nucleation phenomenon in solid-state microcellular foams is identified as a solid-state failure process. This process originates at internal flaws within the gas-polymer matrix, where it is induced by the presence of a state of hydrostatic tensile stress within the polymer matrix. The hydrostatic tensile stress is caused by the presence of the saturating gas within the polymer...

Damping behaviours of the open cell microcellular pure Al foams fabricated by sintering and dissolution process with the relative density of 0?31–0?42 and the pore size of 112–325 mm were investigated. The damping characterisation was conducted on a multifunction internal friction apparatus. The internal friction (IF) was measured at frequencies of 1?0, 3?0 and 6?0 Hz over the temperature range...

Nanocomposites containing poly(methyl methacrylate) (PMMA) and surface functionalized Multi-Walled Carbon Nanotubes (MWNTs) were synthesized. The dispersion of MWNTs in PMMA was characterized using Transmission Electron Microscopy (TEM).The synthesized nanocomposites were successfully foamed using a simple method based on the in-situ generation of supercritical carbon dioxide (CO2</sub...

this investigation presents the effect of various parameters on foam stability and its rheological properties. the underlying idea of this experiment is generating of drilling foam with uniform bubbles. the main problem of foam using is controlling its stability during field application. the most important parameters which cause instability in foam are gravity drainage, gas diffusion and bubble...

The annular foam breaker is one which uses the vacuum and shear force generated by the Coanda effect to break foam. Its effectiveness in destroying drilling foam has been test in wellbore flow simulation loop experimental stand. Experimental results showed that the operating pressure of the annular foam breaker should be larger than 0.6MPa and the stabilizers concentration of the foam drilling ...