Surviving under water : Physiological limitations and technical possibilities

Author: Mårten Silvanius; Oskar Frånberg; Rachel Lance; Blekinge Tekniska Högskola; []

Keywords: ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Diving; diving apparatus; unmanned testing; hyperbaric; scuba; oxygen sensor; composite gas cylinder; carbon dioxide monitoring; decompression; hyperbaric oxygen therapy; Systemteknik; Systems Engineering;

Abstract: The survival of humans in underwater environments necessitates a comprehensive understanding of both physiological factors and advanced technologies. Diving with self-contained underwater breathing apparatuses (SCUBA) remains one of the most common ways for human underwater activities. This thesis explores the challenges of surviving underwater by investigating diving equipment performance and human physiological modeling from both a deterministic and statistical perspective.The research examines the change of gas composition when storing nitrox gas in a composite gas cylinder over extended periods, up to one year. This analysis aims to better understand the implications of long-term storage on gas properties and safety.The efficacy of a signal analysis software algorithm designed to ascertain the accuracy of electronic rebreather oxygen sensors is evaluated. The algorithm's purpose is to provide enhanced safety measures for oxygen sensors integrated into various closed-circuit rebreathers, pursuing reliable data.The reliability of temperature monitoring of carbon dioxide scrubbers is investigated as a method to predict remaining carbon dioxide absorption capacity. This temperature monitoring acts as a crucial "fuel gauge," contributing to diver safety by preventing potential risks associated with scrubber material depletion.The research seeks to explore the principles and methodologies that can be employed to optimize the decompression algorithm, with the purpose of enhancing diver safety during decompression procedures. By employing probabilistic modeling techniques, the research aims to propose innovative solutions to minimize the risk of decompression sickness, contributing to advancements in underwater safety practices.Additionally, the thesis explores the possibilities of altering the oxygen breathing regimen for the Inside Attendant during long-duration hyperbaric oxygen therapy (HBOT) to facilitate rapid decompression without compromising safety.

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