A device includes an adjustable capacitance and a switchable inductance coupled to the adjustable capacitance and configured as a tunable resonant circuit, the switchable inductance comprising a tapped structure having a first inductance and a second inductance.

Tunable radio frequency (RF) front-end architecture using filter having adjustable inductance and capacitance

A control system and data acquisition system for an electrical capacitance tomography sensor comprised of a sensor having a plurality of electrodes, where each electrode is further comprised of a plurality of capacitance segments. Each of the capacitance segments of each electrode can be individually addressed to focus the electric field intensity or sensitivity to desired regions of the electrodes and the sensor.

Interactive and adaptive data acquisition system for use with electrical capacitance volume tomography

A flexible capacitance sensor having multiple layers for communicating signals to a data acquisition system for reconstructing an image of an area or object located in a subject being sensed, the flexible capacitance sensor having a flexible layer of capacitance plates; a flexible shielding ground layer next to the layer of capacitance plates; a flexible layer of signal traces next to the shielding ground layer, where the layer of signal traces has a plurality of trace lines; and where the capacitance sensor is flexible and adapted to be wrapped around the subject being sensed. The sensor is adapted to communicate signals via the plurality of trace lines to a data acquisition system for providing an image of the area or object between the capacitance plates.

Modular Stretchable and Flexible Capacitance Sensors for Use with Electrical Capacitance Volume Tomography & Capacitance Sensing Applications

A method and testing apparatus including first and second load adjusting mechanisms for cyclically applying and reducing first and second tensile loads on a specimen and first and second controllers connected to the first and second load adjusting mechanisms for independently cycling the loads which are additive. Cycling the first and second loads for peak loading and over-peak loading the specimen respectively and controlling first and second loading rates and first and second dwell periods of first and second cycles for peak loading and over-peak loading respectively. The second load adjusting mechanism may include an inflatable over-peak device resting on a plate mounted to a frame of the apparatus. The device includes a hollow housing for supporting the second load, an inflatable bladder within the housing, and a bladder lower portion extending out of an opening at a bottom of the housing when the bladder is inflated.

Apparatus and method for over-peak loading for creep-rupture testing

An oxygenate additive analyzer is provided which detects and determines the presence of oxygen enhancing additives in gasoline or other fuels. The oxygenate additive analyzer includes a portable electronic controller with a fuel cell connected to the controller by a ribbon cable. In operation, a sample of the fuel to be tested is placed in the fuel cell and electrical control signals are transmitted between the controller and the fuel cell. The analyzer measures the direct current conductivity, resonant frequency, and temperature, and such data is analyzed on the unique software system in the microprocessor of the controller. Upon the completion of the fuel analysis, the controller displays the percentage, if any, of added oxygen by weight, lists probable oxygenates as a percentage of volume, and shows the temperature of the fuel sample. The analyzer is a portable unit with a battery power supply. The batteries are rechargeable from both a 120 volt Ac power supply or a 12 volt DC automobile battery-power system. The analyzer includes a computer interface and printer connector to facilitate communication of the information to an external computer and/or printer for logging and storage of information.

Fuel additive analyzer system and process

Measurements of the permittivity of samples over a very wide frequency range and a wide temperature range have previously involved such problems as changing parts of the measuring equipment in different regions of the frequency range, substituting one of the components of a bridge used as part of the equipment to obtain bridge balance, and limited permittivity resolution. The present invention employs a capacitance bridge formed by a sample (C₁,R₁) held between electrodes, a series capacitor C₂ and a detector comprising a high input impedance amplifier 11 and correlators 25. The bridge is balanced by applying voltages of known relative amplitude and phase constructed from outputs having relative phases of 0°, 90° and 180° of two phase-locked oscillators 13 and 14. The voltages are constructed using phase shifters 17, 20, attenuators 19, 21 and summer-driver circuits 12, 22. At low frequencies the applied voltages are obtained from a waveform synthesizer 15. In order to allow for any inaccuracies in the amplitude and phase of the applied voltages, a reference bridge is provided which comprises two capacitors 26, 27 connected in series and a detector which includes a high input impedance amplifier 28, connected between the junction of the capacitors and a common terminal.

Philip Charles Jarrett Pring

Papers

Apparatus and method for determining the permittivity of samples of material over a wide frequency band