Viton GLT O-Ring Resilience Study

Giants, Thomas W.

doi:10.21236/ada402953

Cited by 5 publications

(4 citation statements)

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“…It was shown that these o'rings failed when subjected to intense cold [9][10]. The evidence of failure in these sealing o'rings was first obtained through a logistic regression between failures in these seals and ambient temperatures, and later also proven in a chemical laboratory [11].…”

Section: Previous Workmentioning

confidence: 99%

New Type of Aeronautical Risk Assessment: Performance of Kohonen Self-Organizing Maps in Identifying Brazilian Aircraft with Greater Associated Risks

Silva¹

2022

Preprint

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The purpose of this paper is to present a new way of assessing aeronautical risk using a configuration of Kohonen Self-Organizing Maps (SOM) to identify the Brazilian aircraft more likely to be involved in aeronautical accidents and the riskiest Brazilian aircraft. The technique described is classified as predictive for managing aeronautical risks, according to DOC 9859, and can be used both in the context of prevention and investigation of aeronautical accidents/incidents, as well as in the context of the insurance industry. Using this technique, it was possible to identify the 147 Brazilian aircraft with the highest associated probabilities of occurrence of aeronautical accidents, and the 180 with the highest associated risks. Five years after this identification, the respective percentages of aeronautical accidents/incidents were 34% and 27%. The application of this technique can help achieve the objective of the aeronautical community in determining what, where, and when the next aeronautical accidents and/or incidents will occur. Another aspect of the present work is to demonstrate that data collected by the national civil aviation agency in Brazil can be used to implement a predictive methodology for the management of safety in civil aviation.

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Section: Previous Workmentioning

confidence: 99%

New Type of Aeronautical Risk Assessment: Performance of Kohonen Self-Organizing Maps in Identifying Brazilian Aircraft with Greater Associated Risks

Silva¹

2022

Preprint

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“…[1] The O-ring emissivity is set at 0.94. [2] The heat transfer coefficient for the outside surfaces is evaluated using the Polhausen correlation for flow past a surface with a leading edge. [3] The thermal radiation boundary condition is applied to all surfaces of the recumbent can and to all surfaces except the bottom surface of the upright can, which is assumed to be insulated.…”

Section: Heat Transfer Analysismentioning

confidence: 99%

Pressurization Analysis for Heating of a Screw Top Utility Can Loaded With Plutonium Oxide Powder by a 1273 K Fire

Laurinat

Kesterson

Hensel

2020

Journal of Pressure Vessel Technology

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The documented safety analysis for the Savannah River Site (SRS) evaluates the consequences of a postulated 1273 K fire in a glovebox. The radiological dose consequences for a pressurized release of plutonium oxide powder during such a fire depend on the maximum pressure that is attained inside the oxide storage containers. The oxide storage configuration selected for analysis is can/bag/can, comprised of oxide powder inside an 8.38 x 10-6 m3 stainless steel B vial inside 0.006 kg of polyethylene bagging inside a one-quart screw top utility can of the type commonly used to package solvents or rubber cements. To enable evaluation of the dose consequences, temperature and pressure transients have been calculated for exposure of a typical set of storage containers to the fire. The pressurization analysis credits venting to and from the B vial but does not credit venting or leakage from the can. Due to the low rate of venting from the B vial into the can gas space, the can pressure is nearly independent of the B vial pressure. Calculated maximum pressures are compared to the utility can burst pressure. In lieu of a structural analysis of the utility cans, burst pressures and leakage rates were measured using compressed nitrogen gas. The measured gauge burst pressure was 2.50E5 +/- 0.43E5 Pa. The measured burst pressures are lower than the calculated maximum pressure due to fire exposure, indicating that the utility cans could burst during exposure to a 1273 K fire.

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“…The emissivity for the stainless steel surfaces is set conservatively at 0.9, which is a value typical for soot-covered surfaces. 1 The o-ring emissivity is set at 0.94. 2 The heat transfer coefficient for the outside surfaces is evaluated using the Polhausen correlation for flow past a surface with a leading edge.…”

Section: Heat Transfer Analysismentioning

confidence: 99%

Pressurization Analysis for Flame Heating of a Screw Top Utility Can Loaded With Plutonium Oxide Powder

Laurinat

Kesterson

Hensel

2016

Volume 7: Operations, Applications and Components

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The documented safety analysis for the Savannah River Site (SRS) evaluates the consequences of a postulated 1000 °C (1273 K) fire in a glovebox. The radiological dose consequences for a pressurized release of plutonium oxide powder during such a fire depend on the maximum pressure that is attained inside the oxide storage containers. To enable evaluation of the dose consequences, temperature and pressure transients have been calculated for exposure of a typical set of storage containers to the fire. The oxide storage configuration selected for analysis is can/bag/can, comprised of oxide powder inside an 8.38E−6 m3 stainless steel B vial inside 0.006 kg of polyethylene bagging inside a one-quart screw top utility can of the type commonly used to package solvents or rubber cements. The analysis accounts for pressurization from gases generated by pyrolysis of the polyethylene bagging and evaporation of moisture adsorbed onto the oxide powder. Results were obtained for different can orientations and different surface fire exposures, with and without initial pressurization of the B vial by hydrogen from the radiolysis of moisture. Based on the results of hydrogen back pressure tests for plutonium oxide powders loaded with moisture, the initial gauge pressure from radiolytic hydrogen was set at a bounding value of 82 psig (5.65E5 Pa). The pressurization analysis credits venting to and from the B vial but does not credit venting or leakage from the can. Calculated maximum gauge pressures inside the utility can range from 1.98E5 Pa for an upright can exposed to fire on only one side, to 7.78E5 Pa for an upright can engulfed by fire. Maximum gauge pressures inside the B vial vary from 1.36E5 to 1.43E6 Pa. Due to the low rate of venting from the B vial into the can gas space, the can pressure is nearly independent of the B vial pressure. Calculated maximum pressures are compared to the utility can burst pressure. In lieu of an analytic structural analysis of the utility cans, burst pressures and leakage rates were measured using compressed nitrogen gas. Leakage of gas through the can lid thread and seams prevented the test apparatus from reaching the burst pressure. To achieve the burst pressure, it was necessary to seal the can lid threads and seams by brazing. The measured gauge burst pressure was 2.50E5 +/− 0.43E5 Pa. The measured burst pressures are lower than the calculated maximum pressure due to fire exposure, indicating that the utility cans could burst during exposure to a 1000 °C (1273 K) fire. Leakage rates were measured for cans initially pressurized to a gauge pressure of 1.24E5 Pa. The measured leakage rates were found to be proportional to the gauge pressure inside the can, with a time constant for leakage of 0.424 +/− 0.010 reciprocal seconds. The leakage time constants follow a threshold Weibull distribution.

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Viton GLT O-Ring Resilience Study

Cited by 5 publications

References 0 publications

New Type of Aeronautical Risk Assessment: Performance of Kohonen Self-Organizing Maps in Identifying Brazilian Aircraft with Greater Associated Risks

New Type of Aeronautical Risk Assessment: Performance of Kohonen Self-Organizing Maps in Identifying Brazilian Aircraft with Greater Associated Risks

Pressurization Analysis for Heating of a Screw Top Utility Can Loaded With Plutonium Oxide Powder by a 1273 K Fire

Pressurization Analysis for Flame Heating of a Screw Top Utility Can Loaded With Plutonium Oxide Powder

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