Abstract: The concentration of a material covering a surface is controlled via an equilibrium process. Equilibrium parameters such as a concentration of the provided material, the exposure time of the material to the surface, and the surface area of an attractor applied to the surface are determined utilizing a millimeter sized piezoelectric cantilever sensor. In an example embodiment, the material is provided at a low concentration to the surface until equilibrium is attained. The amount of material accumulated on the surface is determined utilizing the cantilever sensor. The surface area of the attractor and the measured amount of material are utilized to determine the amount of the attractor surface area having the material bound thereto. Knowledge of the equilibrium parameters allows controlled surface coverage of the material on the attractor for any application. The concentration of the material adsorbed on the surface is precisely determinable and repeatable.

Abstract: A method for detection of airborne biological agent using a piezoelectric cantilever sensor that includes a piezoelectric layer and a non-piezoelectric layer. A recognition entity is placed on one or both of the two layers. The antibody that recognizes and binds to the airborne species may be chemically immobilized on the cantilever sensor surface. In one embodiment, the cantilever sensor is attached to a base at only one end. In another embodiment, the sensor includes first and second bases and at least one of the piezoelectric layer and the non-piezoelectric layer is affixed to each of the first and second bases to form a piezoelectric cantilever beam sensor. In this embodiment, resonance is measured via stress on the piezoelectric layer and it has been demonstrated that such sensors are robust and exhibit excellent sensing characteristics in gaseous media with sufficient sensitivity to detect airborne species at relatively low concentrations.

Abstract: The concentration of a material covering a surface is controlled via an equilibrium process. Equilibrium parameters such as a concentration of the provided material, the exposure time of the material to the surface, and the surface area of an attractor applied to the surface are determined utilizing a millimeter sized piezoelectric cantilever sensor. In an example embodiment, the material is provided at a low concentration to the surface until equilibrium is attained. The amount of material accumulated on the surface is determined utilizing the cantilever sensor. The surface area of the attractor and the measured amount of material are utilized to determine the amount of the attractor surface area having the material bound thereto. Knowledge of the equilibrium parameters allows controlled surface coverage of the material on the attractor for any application. The concentration of the material adsorbed on the surface is precisely determinable and repeatable.

Abstract: A light-weight hand-held contraband detection system (10) includes two different sources (74) of low energy gamma rays. Each gamma ray source selectively emits gamma rays at a different energy level, which gamma rays are directed to a specific volume (30) of an object, e.g. a vehicle, being searched. The hand-held detection system also includes a gamma ray detector (42) coupled to a visual indicator (14), which indicator visually indicates the relative number of back-scattered gamma rays reflected back from the object being searched. Back scattering of the emitted gamma rays occurs in differing degrees depending upon the density and contents of the particular volume of the object receiving the gamma rays. Certain changes in density reflect the possibility that contraband, such as drugs, may be concealed in the object being searched. In use, the system is gripped in a hand of the user and passed over the surface of the object being searched.