Polyvinyliden¯uorid (PVDF)-Sonden zur Messung der Druckerzeugung kleiner MunitionskomponentenPolyvinyliden¯uorid (PVDF)-Sonden sind du Ènne (25 mm) Druckaufnehmer, die in der Lage sind, Schock mit Dru Ècken bis zu mindestens 25 GPa mit einer Nanosekunden-Au¯o Èsung unter Impaktbedingungen zu messen.
SummaryPolyvinylidene Fluoride (PVDF) gauges are thin (25 mm) pressure transducers capable of measuring shock pressures up to at least 25 GPa with nanosecond time resolution for impact-loading conditions. In this work the application of PVDF gauges for measurement of the output pressure from small ordnance devices was investigated. Gauge assembly, ®ring ®xtures, and data acquisition and analysis are described in detail. The gauges were used to record the pressure from impact of¯yers accelerated by exploding bridgewire detonators and detonation cord endtips. Consistent peak pressures with standard deviations typically`10% were obtained. The measured pressures were within 10±30% of the pressures calculated from the velocities of the¯yers. The peak pressure correlated with the explosive density of endtips prepared with different explosive loading pressures. These results con®rmed that PVDF gauges produced by the Bauer process yield consistent results useful for characterizing the output of small ordnance devices.
One of the technologies being tested at Ames Research Center as part of the logistics and repurposing project is heat melt compaction (HMC) of solid waste to reduce volume, remove water and render a biologically stable and safe product. Studies at Kennedy Space Center have focused on the efficacy of the heat melt compaction process for killing microorganisms in waste and specific compacter operation protocols, i.e., time and temperature, required to achieve a sterile, stable product. The work reported here includes a controlled study to examine the survival and potential re-growth of specific microorganisms over a 6-month period of storage after heating and compaction. Before heating and compaction, ersatz solid wastes were inoculated with Bacillus amyloliquefaciens and Rhodotorula mucilaginosa, previously isolated from recovered space shuttle mission food and packaging waste. Compacted HMC tiles were sampled for microbiological analysis at time points between 0 and 180 days of storage in a controlled environment chamber. In addition, biological indicator strips containing spores of Bacillus atrophaeus and Ceo bacillus stearothermophilus were imbedded in trash to assess the efficacy of the HMC process to achieve sterilization. Analysis of several tiles compacted at 180°C for times of 40 minutes to over 2 hours detected organisms in all tile samples with the exception of one exposed to 180° C for approximately 2 hours. Neither of the inoculated organisms was recovered, and the biological indicator strips were negative for growth in all tiles indicating at least local sterilization of tile areas. The findings suggest that minimum time/temperature combination is required for complete sterilization. Microbial analysis of tiles processed at lower temperatures from 130°C-150°C at varying times will be discussed, as well as analysis of the bacteria and fungi present on the compactor hardware as a result of exposure to the waste and the surrounding environment. The two organisms inoculated into the waste were among those isolated and identified from the HMC surfaces indicating the possibility of cross contamination.
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