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OBJECTIVES: To investigate safety risks in slowpitch softball by conducting laboratory and experimental studies on the performance of high tech softball bats with polyurethane softballs. To compare the results with the recommended safety standards. METHODS: ASTM standard compression testing of seven softball models was conducted. Using these seven softball models, bat/ball impact testing was performed using seven adult male softball players and six high tech softball bat models to determine mean batted ball speeds. Over 500 bat/ball impact measurements were recorded and analysed. Available pitcher reaction time was calculated from the mean batted ball speed measurements. RESULTS: According to the United States Specialty Sports Association and the Amateur Softball Association, the maximum initial batted ball speed should be 137.2 km/h, which corresponds to a minimum pitcher reaction time of 0.420 second. These experiments produced mean batted ball speeds of 134.0-159.7 km/h, which correspond to available pitcher reaction times of 0.409-0.361 second. CONCLUSION: The use of high tech softball bats with polyurethane softballs can result in batted ball speeds that exceed the recommended safety limits, which correspond to decreased available pitcher reaction times. [ABSTRACT FROM AUTHOR]

Metal membranes play a vital role in hydrogen purification. Defect-free membranes can exhibit effectively infinite selectivity but must also provide high fluxes, resistance to poisoning, long operational lifetimes, and low cost. Alloying offers one route to improve on membranes based on pure metals such as palladium. We show how ab initio calculations and coarse-grained modeling can accurately predict hydrogen fluxes through binary alloy membranes as functions of alloy composition, temperature, and pressure. Our approach, which requires no experimental input apart from knowledge of bulk crystal structures, is demonstrated for palladium-copper alloys, which show nontrivial behavior due to the existence of face-centered cubic and body-centered cubic crystal structures and have the potential to resist sulfur poisoning. The accuracy of our approach is examined by a comparison with extensive experiments using thick foils at elevated temperatures. Our experiments also demonstrate the ability of these membranes to resist poisoning by hydrogen sulfide.