Thermo-Structural Studies of Spores Subjected to High Temperature Gas Environments

Kumar, Rakesh; Saurav, Samarth; Титов, Е. В.; Levin, Deborah A.; Long, Robert; Neely, W. C.

doi:10.2514/6.2009-3752

Cited by 4 publications

(6 citation statements)

References 13 publications

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“…Previous studies have revealed rapid heat transfer from the environment to the spore. Kumar et al [58] showed that the spore took $0.1 ms to reach the surrounding temperature of $400°C. Xing et al [59] showed that the temperature could reach steady state in less than 0.5 ms.…”

Section: Temperature Profiles Of Bs Spores On the Pt Wire Surfacementioning

confidence: 98%

“…Further reduction in viability at higher temperatures was minimal. Grinshpun et al [19,20] exposed aerosolized Bs spores to hot air flow (150-1000°C) and controlled the entire exposure time to be around 0.2-1 s. Due to rapid heat transfer into aerosolized spores [58], the exact time to reach peak temperature could be much shorter. Similarly, the viability of spores started to decrease at 200-250°C.…”

Section: Spore Viability Heated To Fixed Peak Temperatures Under the mentioning

confidence: 99%

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Inactivation of bacterial spores subjected to sub-second thermal stress

Zhou

Orr

Jian

et al. 2015

Chemical Engineering Journal

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Section: Temperature Profiles Of Bs Spores On the Pt Wire Surfacementioning

confidence: 98%

Section: Spore Viability Heated To Fixed Peak Temperatures Under the mentioning

confidence: 99%

Inactivation of bacterial spores subjected to sub-second thermal stress

Zhou

Orr

Jian

et al. 2015

Chemical Engineering Journal

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“…The associated time constants for heat transfer for the coupled and uncoupled cases was found to be approximately 0.7 ms. In our previous work 3 Returning to the top portion of Fig. 6, after 0.3 ms the percentages of water become uniform across the spore and decreases with the time exponentially and levels off to the ambient moisture at approximately 400 ms.…”

Section: B Resultsmentioning

confidence: 93%

“…In either case, it should be noted that the associated time constant is much larger than the typical time constant for pure heat transfer processes which we found to be on the order of milliseconds. 3 2. Sensitivity to diffusion coefficient D w Figure 4 shows the transient response of the percentage of free water w with parameterized variable D w = 7×10 −11 (top), 3.7×10 −10 (middle), and 2×10 −9 m 2 /s (bottom).…”

Section: Numerical Equations Used In Water Diffusion Modeling and mentioning

confidence: 99%

“…The heat transfer rate from the gas to the spore wall was estimated by standard heat transfer correlations 2 and verified by a DSMC analysis. 3,4 It was found that it took just ∼0.4 ms, in comparison to ∼75 ms exposure time, for the spore inner core to reach steady state at the gas temperature in a pure thermal response analysis, ignoring its structural response. Thus it was found that the time constant associated with the heat transfer was much smaller than the exposure time.…”

Section: Introductionmentioning

confidence: 99%

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Deactivation Analysis of Spores in a High Temperature Gas Using a Coupled Water Diffusion and Heat Transfer Model

Zhu

Levin

Setlow

et al. 2012

43rd AIAA Thermophysics Conference

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One of the major mechanisms of deactivating spores is to expose them to elevated temperatures. Experiments carried out in an exposure tube to study the effects on spores in a high temperature gas environment provide evidence of spore deactivation. Microbiological tests show that the more likely reason for spore death is due to either protein damage or some damage to the spore's inner membrane, which are processes that are much slower than heat transfer. 1 In this paper, we employ a coupled water diffusion and heat transfer model to evaluate the associated time constant for the deactivation of spores due to water diffusion. We find that for a standalone spore, the time for diffusion is on the order of 0.1 to several hundred milliseconds and approximately one order of magnitude longer for a spore in an aggregate. This result is in better agreement with the associated time constant of approximately 75ms obtained from the experiment than our previous study that only considered thermal-structural analyses and leads us one step closer to understanding the deactivation mechanism of spores.

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