Fiber Optic Measurement System Research Articles

Experimental Investigation on the Arc Motion with Different Configurations of Quenching Chamber in AC Contactor

SUMMARY Two dimensional optical fiber measurement system is used to investigate experimentally the arc motion and reignition with four different configurations of quenching chamber in an AC contactor. It demonstrates that the splitter plate arrangement has significant effect on the arc motion in arc quenching chamber, and fixing arc runner in the first and last splitter plates benefits to arc motion, and increase the dielectric recovery strength. The results are very useful to design the quenching chamber in AC contactor with high performance.

Performance enhancement on mechanical and electrical effects for on-line fiber-optic bending loss measurement

For an automatic testing of the fiber bending loss parameter, we proposed an on-line fiber optic bending loss measurement system. Many impact factors from the supporting systems, free space coupling alignment, external spatial perturbation device and the other automatic testing systems may degrade the on-line fiber-optic bending loss measurement system. We reduce those impact factors and show the mechanical and electrical improvement in this paper. The accuracy can be improved by 3–5 dB for the proposed on-line bending loss measurement system. Development of an on-line fiber-optic bending loss measurement system can provide a fast-checking solution for jump-line quality improvement on fiber-from-the-desk (FFTD) access network.

Measurement of ultrasonic pressure by heterodyne interferometry with a fiber-tip sensor

A fiber-optic measurement system is described that allows ultrasound to be detected in fluids. It is based on a heterodyne interferometer, and the sensing element consists of a metal-coated fiber tip. The heterodyne technique permits direct acquisition of the sound pressure. The required ac photodetection is carried out with wide bandwidth, and the system provides high temporal and spatial resolution. For optimum performance the system parameters are matched to the sound-wave properties of the current application with the aid of theoretical and numerical calculations. The fiber-optic sensor system was applied to two problems of ultrasonic exposimetry in which the favorable features of the measurement technique were exploited. Shock waves from an electromagnetic lithotripter were investigated by use of the wide bandwidth of the system, and the subharmonic in an ultrasonic cleaner was detected, which indicates cavitation.

Retrofitting-new high voltage XLPE cables substituting paper-insulated power cables in steel pipes

Many utilities still have paper-insulated pipe type cables in service. In the near future they may have to replace some of these systems due to local increases in electric power demand or aged cable insulation. In many cases the steel pipes are well protected against corrosion and thus suitable for further use. For retrofitting in such installations, XLPE-insulated cables offer several advantages. Felten & Guilleaume Energietechnik AG has developed a new three-core XLPE-insulated 64/110 kV cable with reduced insulation thickness (10 mm), that can be pulled into a pipe. In co-operation with VEW ENERGIE AG, the cable performance is being investigated in a field test, that started in October 1996. This long-term loading cycle test will last for three years. The test voltage, applied between conductor and earth, amounts to 127 kV. The temperature is measured with the help of an optical-fiber measurement system. This device is computer controlled and works as a remote monitoring system.

Engineering the development of optical fiber sensors for adverse environments

Optical fiber sensors and measurement systems must be engineered to meet tough environmental requirements necessary for applications outside the laboratory. No generalized computer-aided tools exist to help advance the development, design and use of these systems in the field. Computer-aided design tools currently being developed are described. Structural finite element analyses are coupled with opto-elastic analyses of all-fiber interferometers and serial microbend sensors for the distributed measurement of various physical quantities. The combined analyses are parameterized and implemented on personal computers or workstations for use as design and development tools to determine the performance of different sensor configurations in various environments. Potentially, these computer-aided tools could be used for failure diagnosis and redesigning of existing optical fiber sensors. Performances predicted by the computer simulations are verified with experimental data and numerical analyses from the literature. The long-term goal is to develop user-friendly software packages for sensor manufacturers and end-users.

A rotating arc gas pump for circuit breaking and other applications

A rotating arc circuit breaker is described which uses an auxiliary current source to generate the magnetic field for driving the arc. Test results obtained using optical fiber measurement systems have shown that there are three main arcing phases. Initially the arc rotates at an essentially constant but low velocity, subsequently its velocity oscillates between this and much higher values, and finally the are plasma may become diffuse in nature. Test results obtained with dielectric strength probes have indicated that a unidirectional flow of arc heated gas is generated. The flow is away from the moving contact of the interrupter so promoting good dielectric strength in this critical contact region. The combination of the optical fiber and dielectric probe results indicates two possible modes of gas pumping represented, respectively, by a fan and a piston-type action of the arc. Simplified analytical models for both modes are developed with predictions obtained showing good agreement with the experimental results. Discussion of experimental results suggests that the transition from oscillatory velocity changes to diffuse arcing represents an important parameter for scaling the geometries of future interrupters and arc heaters.

受精卵活性評価のためのファイバー化散乱光計測システム(II)

We evaluated the newly designed fiber-optic measurement system to measure human embryo viability. We measured angular distribution of the light scattering intensity to measure the embryonic mitodchondrial density in which localization may relate to the developmental ability. The size selectivity of the system was investigated with the latex sphere suspensions. The measured light scattering of these suspensions showed good agreement with the calculated results of which scattering distribution were differerent according to the latex diameter. We measured the light scattering of live mouse embryo. Since the measured scattering patterns of the embryo were similar to the pattern abtained from mitochondria equivalent particle, we think the measured light scattering manly originated from mitochondria in the live embryo. Our measurement method might become the practical selecting method of embryo to suppress the multiple pregnancy on current in vitro fertilization-embryo transfer.

A fiber-optic strain measurement and quench localization system for use in superconducting accelerator dipole magnets

A novel fiber-optic measurement system for superconducting accelerator magnets is described. The principal component is an extrinsic Fabry-Perot interferometer to determine localized strain and stress in coil windings. The system can be used either as a sensitive relative strain measurement system or as an absolute strain detector. Combined, one can monitor the mechanical behaviour of the magnet system over time during construction, long time storage and operation. The sensing mechanism is described, together with various tests in laboratory environments. The test results of a multichannel test matrix to be incorporated first in the dummy coils and then in the final version of a 13 T Nb/sub 3/Sn accelerator dipole magnet are presented. Finally, the possible use of this system as a quench localization system is proposed. >

受精卵活性評価のためのファイバー化散乱光計測システム

受精卵活性評価のためのファイバー化散乱光計測システム

Analysis of intracranial pressure.

Methods for the acqusition and analysis of intracranial pressure (ICP) signals are reviewed from clinical and technical perspectives. The clinical importance of ICP monitoring is presented, and methods for ICP transduction are briefly discussed. These methods include intraventricular catheters, subarachnoid screws, epidural techniques, and the new fiberoptic ICP measurement systems. Approaches to the visual analysis of the ICP waveform are presented, with special emphasis on the relationship between the ICP waveform and the arterial blood pressure signal. Methods of computer-based ICP analysis are also reviewed, including histogram and "systems analysis" methods. Methods to predict ICP pressure rises and to estimate intracranial compliance are also discussed. Finally, ICP monitoring is reviewed from the point of view of patient outcome. It is concluded that advanced ICP waveform analysis methods warrant further clinical evaluation to demonstrate their clinical usefulness.

A fiberoptic pressure measurement system

A fiberoptic pressure measurement system

Measurement of tumor ph during microwave induced experimental and clinical hyperthermia with a fiber optic pH measurement system

The influence of hyperthermia on tissue pH was investigated using a modified version of the fiber optic monitoring system. This newly developed system was tested for use in tissues and found to be suitable for pH measurement during microwave induced hyperthermia. The fiber optic pH probe (0.7 mm diameter) could be easily used in the electromagnetic fields produced by the microwave applicators, whereas only the display unit required some shielding. Tissue pH of experimental and clinical tumors was measured concurrently with local microwave hyperthermia treatment. The mean initial intratumor pH of a rat rhabdomyosarcoma was 7.03 (SD 0.13, n = 19) and the pH of human subcutis was 7.45 (SD 0.02, n = 8). In rat tumor a primary pH decrease was observed during heating which was fully reversed during cooling. The coefficient of temperature dependence was -0.016 pH unit/°C (SD 0.004, n = 12). After approximately 1 hr of heating at 43°C a further pH decrease of 0.1–0.3 unit occurred which was not reversed directly after treatment. Measurements during clinical local microwave hyperthermia treatments after radiotherapy revealed similar changes in pH values, primary as well as secondary. The estimated coefficient of temperature dependence for the reversible pH change, which occurred in subcutis as well as in tumor tissue, was −0.016 pH unit/°C (SD 0.004, n = 12). The fiber optic pH measurement system is expected to be a valuable tool in the thorough investigation of temperature and time related pH changes in tumor during experimental as well as clinical hyperthermia treatment.

Performance of an in-vivo, continuous blood-gas monitor with disposable probe.

A fluorescence-based fiber optic measurement system has been developed for monitoring pH, pCO2, and pO2 through a 20-gauge radial artery catheter without compromising capabilities for monitoring arterial pressure or for blood withdrawal. The measuring probe consists of three optical fibers to which the sensing chemistries are attached, and a thermocouple that measures temperature. The probe is designed to meet in-vivo biocompatibility requirements for a one-time use of up to 72 h. The components that are in contact with the patient's blood are nontoxic, nonhemolytic, nonthrombogenic, and sterilizable. Blood compatibility is enhanced by including covalently bound heparin. The in-vitro accuracy of the system has been tested against commercial blood-gas measurement instruments; comparison with tonometry and blood gas values gave r greater than or equal to 0.98 for all three sensors. The standard error for all sensors was within the College of American Pathologists' accuracy guidelines for measuring blood gas. Instrumental drift was minimal, indicating that system performance characteristics should not be the limiting factor in obtaining clinically useful information for up to 72 h. The response times of the sensors in animal and in-vitro studies were less than 2 min, suitable for monitoring physiological changes in blood gas values.

Optical Fiber Measurement Systems and Methods

Optical Fiber Measurement Systems and Methods

Fibre-optic measurement system

Fibre-optic measurement system

Displacement measurements of vibrating transducers

An in-air measurement procedure has been developed to measure the displacement of a vibrating surface. Specifically the amplitude of vibration has been measured for the radiating surfaces of several transducers (primarily tonpilz type) of different designs. The objective being to determine to what degree the radiating head of a transducer acts as a rigid piston at resonance. In some cases it was known prior to measurement that the radiating head was vibrating with a modal structure, i.e., the corners vibrated out of phase with the center. A fiber optic measurement system was used in order to perform noncontact vibration displacement measurements. The usable frequency range is dc to 100 kHz. Displacement amplitudes on the order of one micron have been measured accurately. The apparatus, which was built at the Applied Research Laboratory at The Pennyslvania State University, allows displacement mapping of the entire surface of a transducer's radiating head. [Work supported by NAVSEA.]

A universal fiber-optic (UFO) measurement system based on a near-IR fiber Raman laser

A universal fiber-optic measurement system, which is useful for measuring loss and dispersion in the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.06-1.6 \mu</tex> m wavelength region, is described. The source is a silica fiber Raman laser pumped by a mode-locked and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</tex> -switched Nd:YAG laser at 1.06 μm. Subnanosecond multiple-Stokes pulses in the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.1-1.6 \mu</tex> m wavelength region are generated in a low-loss single-mode silica fiber. The use of this near-infrared fiber Raman laser for characterizing various transmission properties of single and multimode test fibers is demonstrated. Loss spectra, intramodal dispersion, and intermodal dispersion data are obtained in the wavelength region of minimum loss and minimum material dispersion for silica fibers.