Abstract: An optical pump unit may include a line voltage transistor, coupled between an input side and an output side of the optical pump unit. The optical pump may further include a DC-to-DC converter, having an input side coupled to the line voltage transistor; an optical pump assembly, coupled to an output side of the DC-to-DC converter; a current control assembly, coupled to the optical pump assembly; a throttle back control assembly, having an output coupled to the current control assembly, and a current/voltage sensor, to monitor a line current and voltage drop in the optical repeater, and being coupled to an input of the throttle back control assembly. As such, the throttle back control assembly may be configured to send a signal to the current control assembly to reduce a power at the optical pump assembly when a decrease in line current or voltage drop takes place.

Abstract: A system for spectral induced polarization measurement of a formation is provided. The system provides an intelligent module to be utilized in performing spectral induced polarization (SIP) measurements for geophysical studies or otherwise. The system includes a instrument that includes a housing configured to be inserted into a surface opening. The housing houses a signal generator that generates an excitation signal. A drive electrode directs the excitation signal into the material adjacent the housing. A plurality of electrodes sense the voltage and/or current in the material adjacent the housing and a processor processes the sensed voltage and/or current to measure a property of the material. The system also provides a configuration in which a plurality of instruments configured for spectral induced polarization measurements are interconnected to provide communication, synchronization, a common reference signal or power.

Abstract: A system for spectral induced polarization measurement of a formation is provided. The system provides an intelligent module to be utilized in performing spectral induced polarization (SIP) measurements for geophysical studies or otherwise. The system includes a instrument that includes a housing configured to be inserted into a surface opening. The housing houses a signal generator that generates an excitation signal. A drive electrode directs the excitation signal into the material adjacent the housing. A plurality of electrodes sense the voltage and/or current in the material adjacent the housing and a processor processes the sensed voltage and/or current to measure a property of the material. The system also provides a configuration in which a plurality of instruments configured for spectral induced polarization measurements are interconnected to provide communication, synchronization, a common reference signal or power.

Abstract: An on-line sensing system and method for monitoring in real-time thermal-oxidative breakdown, water contamination, and/or fuel dilution conditions in operational engine lubricating oils. The method of the invention includes an electrochemical impedance analysis technique specific to the particular oil to be monitored. Sensing devices having of at least two electrodes are configured for direct installation in an existing access port, or drain port, of a lubricating oil reservoir. An AC voltage waveform is applied to the sensing device (preferably less than 100 Hz) to produce voltage and current responses between the appropriate electrodes contacting the oil. The magnitude impedance |Z| and phase angle components of the complex impedance are used to characterize the quality and/or condition of the engine oil under test. The system also provides an electrical indication indicative of the percentage remaining useful life of the oil.

Abstract: A method and apparatus is provided for controlling the bias point of a Mach-Zehnder modulator. The method begins by applying a dither signal to a DC bias that is applied to a Mach-Zehnder modulator. A component of an optical output signal provided by the Mach-Zehnder modulator that is synchronous with the dither signal is detected. The dither signal is adjusted to maintain the detected component of the optical output signal at a substantially constant value.

Abstract: A method and apparatus is provided for controlling the bias point of a Mach-Zehnder modulator. The method begins by applying a dither signal to a DC bias that is applied to a Mach-Zehnder modulator. A component of an optical output signal provided by the Mach-Zehnder modulator that is synchronous with the dither signal is detected. The dither signal is adjusted to maintain the detected component of the optical output signal at a substantially constant value.

Abstract: This invention is directed to a sensing system and method for detecting in real-time oil degradation, water contamination, and fuel dilution in operational engine oils for internal combustion engines. The method of the invention uses an electrochemical impedance analysis technique. The sensing system has a multi-electrode sensor element that can be immersed in the engine oil being monitored. The electrode element has at least two electrodes configured so that it can be directly mounted within the oil reservoir of an internal combustion engine. The sensor configuration with a dielectric lubricant contained between the electrodes defines an electrochemical sensor output-impedance-circuit that produces an indication of the operational oil's quality or deterioration. A sinusoidal voltage waveform is applied across the electrodes of the sensor to produce a frequency dependent current through the oil and electrode system.

Abstract: A hard copy recorder is provided in which paper or film is moved along a paper path by a motor-driven roller. A tension-measuring dancer measures paper or film tension. The position of the dancer is sensed by an optical sensor, which produces a signal representative of paper or film tension. The paper or film tension signal is used to selectively couple one signal from a number of sources of predetermined different frequencies to the motor to control its speed in accordance with the sensed paper tension.

Abstract: Self-sufficient incubation assembly for the in vitro cultivation of microorganisms such as bacteria and for being energized by a self-contained energy source, including a heater for heating means, such as a culture growth dish assembly or a cuvette, for receiving a culture growth medium seeded with microorganisms, to a physiological temperature to cultivate the microorganisms, and electrical circuitry which interconnects the heater with the energy source and which includes a temperature control element in intimate physical contact with the seeded culture growth receiving means to cause the temperature of the control element to be substantially the same as the temperature of the medium; the electrical circuit in operation produces heat and due to its intimate physical contact with the means for receiving the seeded culture growth medium supplements the heating of the medium by the heater and the supplementation reduces the total energy required to be supplied by the energy source to cultivate the microorganism