Accession Number : ADA139024

Title :   Characterization of Humidity Sensors and Physical Properties of H20.

Descriptive Note : Final rept. Jan 82-Aug 83,

Corporate Author : SOUTH DAKOTA SCHOOL OF MINES AND TECHNOLOGY RAPID CITY DEPT OF PHYSICS

Personal Author(s) : Ashworth,T.

Report Date : 01 MAR 1984

Pagination or Media Count : 46

Abstract : Commercially available humidity sensors have been evaluated. There do not appear to have been any significant advances in aluminum oxide devices recently. A new sensor (Thunder Scientific BR-101B) is a little faster than the aluminum oxide types (but not as fast as the manufacturer claims), and it has the significant advantage of a near purely resistive impedance. A monitoring system capable of following fast changes (milliseconds) in sensor parameters has been developed; it detects and records in logarithmic fashion both the magnitude and phase of th sensor's response to a sinusoidal signal. Thermal conductivity of pure ice (Ih) and tetrahydrofuran hydrate has been measured in the temperature range 45 to 200K. The data on the pure ice is in good agreement with previous results. Our data on the clathrate hydrate is a little higher than previous measurements by a radial flow method, but we also find the conductivity to be a factor of 5 (at 200K) to 20 (at 45K) lower than that of pure ice. We find an identical temperature dependence to that found previously, and we extended measurements down to 45K. (Author)

Descriptors :   *Hygrometers, *Water, *Physical properties, *Thermal conductivity, Water vapor, Ice, Monitoring, Aluminum oxides, Clathrate compounds, Hydrates, Radial flow, Temperature, Furans, Hydroxyl radicals

Subject Categories : Meteorology
      Test Facilities, Equipment and Methods
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE