Finding people trapped inside of a burning house is extremely difficult,dangerous, and time consuming. Smoke, heat, unfamiliar floor plans, and possiblestructural collapse all combine to challenge a firefighter's ability to find aperson. Thermal imaging cameras, the most advanced technology available tofirefighters today, are able to see through smoke but are unable to see throughwalls and household items. Through-wall radar and vital-sign detectionradar offer an imaging modality that may be able to help firefighters findvictims from outside of a room or even a house.Flames can interact with electromagnetic (radar) waves because the flames createa weakly-ionized plasma. Previous work has looked at small flames fueled by puregases or flames from wildfires. Combustable items in a house are typicallypetroleum-based products that have different combustion reactions compared topreviously studied flames and fire-induced plasmas. Because of this, it isunknown how electromagnetic waves interact with flames found in a house fire.This dissertation investigates the question of how electromagnetic wavesinteract with flames in a house fire. This is an open problem, with manyvariables, that poses a subtle and difficult measurement task. This work focuseson creating experimental techniques to explore this problem. From anelectromagnetic metrology perspective, the physical phenomena of interest aredifficult to measure due to ill-defined physical boundaries, characteristicslengths of varying magnitude, inhomogeneity, and varying time scales. Theexperimental methods studied here primarily focus on transmission measurementsthrough flames a few feet in height. Additionally, this work presents aproof-of-concept two-wire transmission line for bench-scale,material-characterization of solids, liquids, gases, and flames.Results from this work provide a metrological foundation for future studies inthis area. An experimental setup that can withstand direct exposure to flameswas developed and preliminary measurements recorded. Data taken during thedevelopment of this setup showed a time-dependance that corresponded totransmissions through the flame and the solid fuelbeing consumed. Calibration procedures were used to verify measurements ofstandard materials; the calibration procedure should be refined for largerflame measurements. Transmitters were placed inside of a burning house andsignal propagation was measured, which required the design of fire-proofenclosures for the transmitters. Measured results demonstrated thattransmissions may not be affected when sent from a firefighter inside of a housewith fire conditions suitable for an offensive, interior attack. It is unknownif severe conditions, such as a flashover, would affect transmissions. Plasmaswere observed in interferometric measurements of live-fire experiments performedin the laboratory.This work has explored an open problem in electromagnetics with live-savingapplications to the fire service. Results from this work warrant additionalstudy in this area to improve techniques, with the goal of puttingsearch-and-rescue radars into the hands of firefighters.
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