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Adamovsky, Grigory

Publications and source records attributed to Adamovsky, Grigory.

48 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Optical techniques for determination of normal shock position in supersonic flows for aerospace applications

Techniques for the quantitative determination of shock position in supersonic flows using direct and indirect methods is presented. A description of an experimental setup is also presented, different configurations of shock position sensing systems are explained, and some experimental results are given. All of the methods discussed are analyzed to determine the ease of technology transfer from the laboratory to in-flight operation.

Adamovsky, Grigory↗
NASA NTRS1990

Optical techniques for determination of normal shock position in supersonic flows for aerospace applications

Techniques for the quantitative determination of shock position in supersonic flows using direct and indirect methods is presented. A description of an experimental setup is also presented, different configurations of shock position sensing systems are explained, and some experimental results are given. All of the methods discussed are analyzed to determine the ease of technology transfer from the laboratory to in-flight operation.

Adamovsky, Grigory↗
NASA NTRS1990

Photoelastic transducer for high-temperature applications

A design for a birefringence transducer for high-temperature applications is described. The spring element and the readout instrumentation are addressed. A pressure transducer based on the concept has been built and successfully tested at temperatures up to 600 C.

Redner, A. S.↗
NASA NTRS1989

Fiber optic sensing systems using high frequency resonant sensing heads with intensity sensors

Optical fibers have an inherent capability of transmitting high bandwidth analog and digital signals. To apply this property of fiber optics to remote sensing, special sensing heads as well as signal processing electronics have to be developed. In systems employing intensity modulating sensors, there is also a need for a referencing technique to compensate for changes in the transmission of the connecting fibers and light source intensity. Fiber optic sensing systems incorporated in sensing heads of a special configuration are discussed. Different modes of operation as well as resonant conditions are explained. Theoretical and experimental analyses are also given.

Adamovsky, Grigory↗
NASA NTRS1988

Fiber optic sensing systems using high frequency resonant sensing heads with intensity sensors

Optical fibers have an inherent capability of transmitting high bandwidth analog and digital signals. To apply this property of fiber optics to remote sensing, special sensing heads as well as signal processing electronics have to be developed. In systems employing intensity modulating sensors, there is also a need for a referencing technique to compensate for changes in the transmission of the connecting fibers and light source intensity. Fiber optic sensing systems incorporated in sensing heads of a special configuration are discussed. Different modes of operation as well as resonant conditions are explained. Theoretical and experimental analyses are also given.

Adamovsky, Grigory↗
NASA NTRS1988

Fiber-optic displacement sensor with temporally separated signal and reference channels

A fiber-optic displacement sensor with temporally separated signal and reference channels is proposed. The sensing technique used is based on determining the relative amplitude of the signal and reference pulses that together form a double pulse. The relative amplitude of the pulses in the double pulse is a function of the displacement. A setup to generate the double pulse with individual pulses of 5-ns duration and 10-ns delay is described. A novel signal processing technique, used to determine the relative amplitude of such pulses in the double pulse by analyzing different portions of the signal spectrum, is explained. Experimental data are also provided.

Adamovsky, Grigory↗
NASA NTRS1988

Fiber optic sensors with internal referencing

The main problem with amplitude modulating type sensors is that any variation in the intensity of the optical signal which occurs throughout the sensing system is interpreted by the photodetector as resulting from the sensor itself and is reflected as an error in the sensed parameter. To account for these errors, a referencing technique with the signal and reference channels separated in the time domain over the same fiber link can be used. Selected sensing and signal processing techniques involving temporally separated signal and referencing channels are described. A transition from the time into the frequency domain is also discussed. Experimental data are presented.

Adamovsky, Grigory↗
NASA NTRS1987

Referencing in fiber optic sensing systems

Different techniques to account for losses induced by the environment on signals in intensity modulation fiber optic sensing systems are described and analyzed.

Adamovsky, Grigory↗
NASA NTRS1987

Referencing in fiber optic sensing systems

Different techniques to account for losses induced by the environment on signals in intensity modulation fiber optic sensing systems are described and analyzed.

Adamovsky, Grigory↗
NASA NTRS1986

Fiber-optic thermometer using temperature dependent absorption, broadband detection, and time domain referencing

A fiber-optic thermometer based on temperature dependent absorption in Nd(3+) doped glass is demonstrated over the 298-573 K range. A broadband detection technique allows the use of the complete spectrum of a pulse modulated light emitting diode. A fiber-optic recirculating loop is employed to construct a reference channel in the time domain by generating a train of pulses from one initial pulse. A theoretical model is developed, and experimental data are shown to compare well with the theory. Possible sources of error and instability are identified, and ways to enhance the performance of the system are proposed.

Adamovsky, Grigory↗
NASA NTRS1986

Time domain referencing in intensity modulation fiber optic sensing systems

Intensity modulation sensors are classified by the way in which the reference and signal channels are separated: in space, wavelength, or time domains. To implement the time-domain referencing, different types of fiber-optic loops have been used. A pulse of short duration sent into the loop results in a series of pulses of different amplitudes. The information about the measured parameter is retrieved from the relative amplitudes of pulses in the same train.

Adamovsky, Grigory↗