Abstract: A detector for detecting vapors emitted from analytes includes a housing, a pump and a sensing assembly. The housing has an inlet, an outlet and an enclosed sensing volume therebetween. The pump communicates with the housing for moving a carrier sequentially through the enclosed sensing volume at a predetermined flow rate. The sensing assembly senses the vapors of the analyte delivered by the carrier as the carrier passes through the housing. The sensing assembly includes a sensing unit constructed of an amplifying fluorescent polymer, a source of excitation, a detector, and a convertor assembly.

Abstract: A detector for detecting vapors emitted from analytes includes a housing, a pump and a sensing assembly. The housing has an inlet, an outlet and an enclosed sensing volume therebetween. The pump communicates with the housing for moving a carrier sequentially through the enclosed sensing volume at a predetermined flow rate. The sensing assembly senses the vapors of the analyte delivered by the carrier as the carrier passes through the housing. The sensing assembly includes a sensing unit constructed of an amplifying fluorescent polymer, a source of excitation, a detector, and a convertor assembly.

Abstract: A detector for detecting vapors emitted from analytes includes a housing, a pump and a sensing assembly. The housing has an inlet, an outlet and an enclosed sensing volume therebetween. The pump communicates with the housing for moving a carrier sequentially through the enclosed sensing volume at a predetermined flow rate. The sensing assembly senses the vapors of the analyte delivered by the carrier as the carrier passes through the housing. The sensing assembly includes a sensing unit constructed of an amplifying fluorescent polymer, a source of excitation, a detector, and a convertor assembly.

Abstract: A detector for detecting vapors emitted from energetic compounds includes a housing, a pump and a sensing assembly. The housing has an inlet, an outlet and an enclosed sensing volume there between. The pump communicates with the housing for moving a carrier gas sequentially through the enclosed sensing volume at a predetermined flow rate. The sensing assembly senses the vapors of the energetic compound delivered by the carrier gas as the carrier gas passes through the housing. The sensing assembly includes a sensing unit constructed of an amplifying fluorescent polymer, a source of excitation, a light detector, and a convertor assembly.

Abstract: A hydraulic force servo system provides apparatus for compensating for unequal loading forces applied to an actuator piston, and for unequal areas on opposite faces of the piston. Asymmetric nonlinear differential hydraulic force feedback from the output side of a force servovalve is summed with the hydraulic control signal inputs to the output stage of the servovalve at hydraulic summing junctions. Impedances offered by orifices in the feedback lines determine the amount of feedback. Nonlinear characteristics of the feedback method serve to compensate for nonlinearities in the servo actuator and system. The impedance ratio of the orifices is selected as a function of the known or postulated asymmetry of the loading forces to be applied to the actuator piston, and the ratio of the areas of the opposing faces of the actuator piston. Hydraulic damping further improves linearity and stability.

Abstract: An apparatus for reducing harmonic distortion and causing a more linear response in a hydraulic vibrator apparatus which generates a seismic signal into the surface of the earth is disclosed. The force developed in the actuator of a hydraulic vibrator is directly related to pressure applied to the hydraulic piston. Conventional vibrators use flow control type servovalves to develop this pressure. Changes in loading due to earth surface conditions reflect back as changes in pressure across the hydraulic piston. Pressure can be better controlled in the actuator such that it varies only as a function of the input signal, and the natural response of a vibrator can be made more linear, and the harmonic distortion can be reduced by using a pressure control type servovalve.

Abstract: An apparatus and method are disclosed which monitor the position of a scanner platform and, in response to roll of the platform, compensate a scanner device mounted thereon to maintain the center lines of the angles of scan in alignment as defined by a line parallel to the direction of movement of the scanner platform relative to the object which is scanned.

Abstract: The invention provides a vertical velocity signal and an integration signal, respectively, of two detected ambient conditions. The signals are summed, in a selectable ratio, and compared with a predetermined altitude set point. When there is a difference between the summed outputs and the altitude set point, an altitude control signal is provided to control a vertical propulsion system of an object whose altitude is to be maintained above a terrain.