In this paper, a new anisotropic material concept namely composite foam is proposed as an alternative to next generation helmet liners which can potentially reduce head rotational accelerations. The Layered Composite foam concept comprises of foam layers with different densities which are glued to each other in a parallel or series configuration. Initial experiments such as static combined shea...

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...

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...

Refractometry of air is a central problem for interferometer-based dimensional measurements. Refractometry at the 10−9 level is only valid if air temperature gradients are controlled at the millikelvin (mK) level. Very precise tests of second-generation National Institute of Standards and Technology (NIST) refractometers involve comparing two instruments (two optical cavities made from ultralow...

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...

In fluoroscopic contrast study for interventional procedure, liquid contrast agent may be diluted in body fluid, losing its contrast effect. We developed a novel contrast agent of "foam state" to maintain contrast effect for enough time and performed a comparative study of physical properties and its usefulness in experimental intervention in animal model. The mean size of microbubble of foam c...

Lost-foam (also known as Expendable Pattern Casting, EPC) is an ever-growing metal casting technique, capable of producing complex metal components without parting lines. Mold preparation for lost-foam casting is typically accurate, but expensive and slow. The goal of this research was to develop a new approach for producing rapid lost-foam molds. With this new approach, patterns generated by S...