Browsing by Author "Walker, Mark"

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Assessing the safety of training firefighters with the minimum requirements for firefighter garments
(Springer, 2021-03-23) Clark, Thomas B. B; Walker, Mark; Mendham, Frank
Every year, high numbers of firefighters are injured at fire incidents. A primary cause of moderate to severe injury can be linked to the protective garments worn by firefighters and understanding the limits of these protective garments is crucial for their safety. It would be substantially advantageous to firefighter safety if their available safe escape time is included in building design. To do this, the heat protective performance of firefighter garments needs to be translated into a tenable time. In this study, the minimum Thermal Protective Performance (TPP) rating of firefighter garments was investigated and found to compare well to known firefighter environments. This TPP rating was then used to further process the heat flux results from a CFD based fire model to determine an available safe escape time for firefighters. The probability of firefighters being injured was required in this study. It was used to assess the accuracy of the fire model in estimating the critical heat flux required to prevent a safe available escape time.
Wear and flexural strength comparisons of alumina/feldspar resin infiltrated dental composites
(South African Dental Association, 2008) Le Roux, Andre Rayne; Lachman, Nirusha; Walker, Mark; Botha, T.
Introduction: Incorporating a feldspar chemical bond between alumina filler particles is expected to increase the wear-resistant and flexural strength properties. Aims and Objectives: An investigation was carried out to evaluate the influence of the feldspar chemical bonding between alumina filler particles on wear and flexural strength of experimental alumina/feldspar dental composites. It was hypothesized that wear resistance and flexural strength would be significantly increased with increased feldspar mass. Methods: Alumina was chemically sintered and bonded with 30% and 60% feldspar mass, silanized and infiltrated with UDMA resin to prepare the dental restorative composite material. Results and conclusions: Higher wear-resistant characteristics resulted with increased feldspar mass of up to 60% (p<0.05). Higher flexural strength characteristics resulted as the feldspar mass was increased up to 60% (p>0.05). Feldspar chemical bonding between the alumina particles may improve on the wear-resistance and flexural strength of alumina/ feldspar composites.