Browse Topic: Fire detection
Type-II interband cascade lasers (ICLs) based on the GaSb material system represent an enabling technology for laser absorption spectroscopy in the 3-to-5-μm wavelength range. Instruments operating in this spectral regime can precisely match strong absorption lines of several gas molecules of interest in atmospheric science and environmental monitoring, specifically methane, ethane, other alkanes, and inorganic gases. Compared with non-semiconductor-based laser technologies, ICLs can be made more compact and power efficient, ultimately leading to more portable, robust, and manufacturable spectroscopy instruments.
A miniaturized Schottky diode hydrogen and hydrocarbon sensor with the structure of catalytic metal-metal oxide-silicon carbide (SiC) has been developed. The major innovation of this work is the use of the metal oxide, palladium oxide (PdOx), as a barrier layer between the catalytic metal and the SiC in the gas-sensing structure. A major advantage of adding a PdOx barrier layer between the gate metal and the SiC is to prevent and alleviate chemical reactions between the gate metal and the SiC. Without the PdOx barrier layer, the gate metal and the substrate can easily form metal silicides at high temperature, leading to diode structure disruption. The metal oxide barrier layer can be incorporated into a gas-sensing structure by standard deposition techniques in a controlled manner. This oxide naturally forms with Pd in Pd-based gas sensor systems and can disrupt the gas sensor structure when formed in situ in an uncontrolled manner. However, purposely including this oxide in the
Wildfires that start in backcountry areas sometimes burn for hours before being detected and reported. Satellites offer a vantage point from which infrared sensors can detect fires. Individual satellites in low Earth orbit (LEO) offer infrequent overpasses, making the delay from ignition to detection unacceptably long. Geostationary satellites offer a platform from which to maintain a round-the-clock vigil, but lack geographic precision, and cannot detect a rather small fire within a large pixel definitively above noise.
This ARP addresses the issue of passengers smoking in aircraft lavatories and the need to improve warnings about the danger of fire caused by smoking.
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