Negative Poisson's ratio foam was used in the development of seat cushions which exert reduced peak pressure upon the skin of seated persons. Foam processing techniques were scaled up. A longer processing time was required for cushion size samples in comparison with small samples. Pressure distributions on a seated subject were measured using a pressure-sensitive array. Seated pressure distribu...

Performance advantages of incorporating fluid channels into foam made of DERTEX VN600 (Vinyl Nitrile) are evaluated. This foam has the potential to replace the traditional foam material of helmet liners, like Expanded Polystyrene (EPS). Experiments involved dropping a certified size E headform vertically onto a flat, solid anvil. Elastically deformable and resilient VN foam outperformed EPS dur...

Finite Element Analysis (FEA) was used to model viscoelastic effects in the compression of polyurethane (PU) foam. Modelling of the impact compression of foam cubes predicted that a compressed region propagated through the sample, causing step increases in the stress traces. Modelling of head impacts on gymnastic ‘crash’ mats, made of PU chip foam, revealed that the majority, but not all, of th...

An analytical model is developed for the performance of a microcellular radio network in the presence of co-channel interference and additive white Gaussian noise. The modulation schemes considered are BPSK, BFSK, and QPSK. The multiple-access channel is statistically modeled by one Rician-distributed desired signal and several uncorrelated Rayleigh plus log-normally shadowed interfering signal...

A new medium 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 microcellula...

Future microcellular systems will require distributed network control. A packet-switched network is particularly suitable for this requirement. Moreover, packet switching naturally accommodates speech activity detection to improve Vation-ALOHA protocol for packet speech transmission from wireless terminals to a base station. Because PRMA is a statistical multiplexer, the channel becomes congest...

Endothelial dysfunction is an established clinical marker of early coronary artery disease and has been shown to be associated with increased cardiovascular morbidity and mortality. New concepts now extend the view of endothelial dysfunction beyond the traditional involvement of the coronary arterial endothelium alone. Recent research indicates that the coronary vessel wall, especially the vasa...

This paper presents a numerical study of microwave scattering and emission from a foamcovered ocean surface. The foam layer is modeled as an inhomogeneous layer with randomly rough airfoam and foam-seawater boundaries. Kelvin’s Tetrakaidecahedron structure is selected as the skeleton for simulating the air bubbles in the foam layer. The electromagnetic characteristics of the foam layer, includi...

abstract: background: release of volatile organic compounds (vocs) in industrial and urban area have adverse effects on human health and  environment. the aim of this study was removal of gaseous toluene, as the most of pollutants among vocs, by using of tio 2 nanoparticles coated on nickel foam substrate. methods: tio 2 nanoparticles prepared by sol gel method and coated on nickel foam. morpho...