Abstract: A nasal air filtration device includes a pair of either planar or concave-convex filters, a support structure incorporating a pair of generally annular bases or sleeves for supporting the filters, and a bridge that couples the bases or sleeves to maintain them in a desired spaced-apart relation and to determine a desired angular relationship. The support structure is insertable into the nasal cavities to position the filters within corresponding nasal cavities. Flexible rims maintain the support structure and the filters in spaced-apart relation to the surrounding nasal wall. The rims conform to surrounding nasal tissue to form seals. The rims can be selectively inclined to facilitate insertion and resist accidental removal. In certain embodiments the device is combined with a filter that covers the mouth to provide an air filtration system.

Abstract: A fire detector and method for generating an alarm signal in response to a fire uses an NDIR sensor to generate a detector signal based upon one or more absorption bands selected from the 15.1? absorption band of CO2, the 6.27? absorption band of H2O and the 4.67? absorption band for CO and generates an alarm signal when a signal processor receives the detector signal and a preselected criterion is met that is indicative of the onset of a fire based upon an analysis of the detector signal using a detection algorithm that relies upon a trending pattern of the detector signal such as recognizing a substantial drop in the detector signal strength. The fire detector has a waveguide sample chamber (which can be of a re-entrant design) with at least one opening covered by a thin filtering membrane and a heat exchanger thermally connected to the sample chamber with at least one opening covered by another thin filtering membrane.