Abstract: An above-ground, A-frame wildfire shelter designed to withstand extreme wildfire conditions is disclosed. The structure is fireproof and is fabricated entirely from non-combustible metals to ensure durability under severe thermal exposure. The A-frame roof configuration offers significant advantages, including reduced gravitational load and inherent angular bracing, as the opposing rafters support one another. Roofing panels are mounted directly to the rafters for structural integrity. To address prolonged exposure to temperatures approaching 1,000° C., the design incorporates passive cooling through hollow, rectangular rafters. These rafters facilitate airflow, drawing cooler air from near ground level and discharging heated air above the roofline. Additionally, the A-frame geometry can be scaled to accommodate an integrated off-grid electrical system, enabling geothermal cooling to mitigate soak-back heat within the shelter.

Abstract: A system for sensing and indicating the angular position of a shaft through 360 degrees of rotation using a two-axis magnetoresistive microcircuit, a two pole magnet which rotates with the input shaft, a two channel operational amplifier, and an electromechanical device such as air core meter indicator, or an electronic computer to provide remote shaft angle indication. The magnetoresistive microcircuit consists of two Wheatstone bridges with magnetic field sensitive resistor elements. The two pole magnet is attached to the input shaft and configured to provide a uniform, low level magnetic field with maximum intensity less than that which will saturate the magnetoresistive sensors. Operational amplifier circuits are trimmed to eliminate sensor offset, match scale factors for the two channels, and amplify the differential bridge sensor signals. As the input shaft rotates, sinusoidal signals V1 and V2 are obtained from the amplifiers with equal amplitude and a 90-degree phase shift.