A filter system for a free-standing air blowing fan having a support stand, motor driven fan blades and a cage about at least portions of the blades, is described. The memristor has a device response that is an integrated voltage versus an integrated current. Alternatively, hygroscopic polyol particles are coated with an inorganic material to provide a polyol having a reduced capacity for moisture absorption. It has been demonstrated that single-loop, fan-folded fascia lata sheets can exhibit mechanical properties that compare favorably with existing cruciate ligament grafts. The detected gamma ray spectra can be analyzed using a combination of standard spectra and subtracting at least one spectral component of the background in accordance with the background ratio.