Review of NDT techniques at radio and microwave frequencies

Review of NDT techniques at radio and microwave frequencies

ND T Abstracts of a ~ u r i n g and computing complex for the radiowave inspection of laminated dielectric structures based on the method of synthesiz...

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ND T Abstracts of a ~ u r i n g and computing complex for the radiowave inspection of laminated dielectric structures based on the method of synthesizing the envelope of the radio pulse signal. The article presents the results of tests of the complex in the inspection of single-layer and double-layer structures including composite materials, and it presents the main technical characteristics of the complex. 44838

Wang, M.S.; Borrego, J.M.

High-resolution scanning microwave electric-field probe for dielectric c o n s t a n t uniformity measurement Materials Evaluation, Vol. 48, No. 9, pp. 1106-1109 (Sep. 1990) A novel microwave eioctric-field probe consisting of a microstrip resonator has been devised to measure the nonuniformity in dielectric constant of dielectric materials at the X-band by relating the resonant frequency shift of the probe to the variation in dielectric constant. A calibration curve relating the dielectric constant of samples to the resonant frequency shift of the microwave electric-field probe is empirically obtained by measuring two standard dielectric samples and free space. Two computer programs, Touchstone and Adam, are used to provide a theoretical understanding for this calibration curve. The sensitivity of our measurement system to resonant frequency shift is 0.2 MHz, which corresponds to an absolute variation of 0.04-0.1 in dielectric constant.

44601 Kozlov, V.P. C i r c u l a r l y polarized radio waves in multilayer dielectriccoating flaw detection Soviet Journal of Nondestructive Testing, Vol. 25, No. 9, pp. 636-641 (May 1990) A method is described for monitoring defects in layered insulators by means of circularly polarized radio waves. A prototype has been used to show that one can detect micropeeling in a multiiayer medium having a variable thickness.

Akhmetshin, A.M.; Myakin'kova, L.V. Wide-band U H F thickness measurement of laminated structures: development and investigation of the method of linear p r e d i c t i o n 44330

Soviet Journal of Nondestructive Testing, Vol. 25, No. 6, pp. 398-404 (Feb. 1990) The article discusses the possibility of improving the reliability of evaluations of the electric thicknesses of laminated structures by the method of linear prediction and by accelerating the processing of experimental dAtA. The noise-proofness of the method is investigates, and a detailed experimental verification is carried out on the example of two-layered dielectric structures in the frequency range 25-37 GHz.

docks. The technique is based on the attenuation of a radar signal emitted from a radar unit in the presence of chloride.

Zoughi, R. Review of NDT techniques at radio and microwave frequencies

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Review of Progress in Quantitative Nondestructive Evaluation, Voi. 8A. Edited by D.C. Thompson and D.E. Chimenti, pp. 337-344. Plenum Press (1989), ISBN 0 306 43209 9 Clearly the natural transition for NDT science is the use of higher frequencies, namely microwaves. The behavior of EM waves at these frequencies is well known and their interaction with material media has received a great deal of attention. Research in microwave NDT, with defect detection and classification in mind, has received minimal attention. However, microwaves show great promise in developing techniques and tools for NDT purposes.

Konev, V.A.; Mikhnev, V.A. Radio-wave instrument for measuring the parameters of

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dielectric sheet ANB-645 Soviet Journal of Nondestructive Testing, Vol. 25, No. 2, pp. 116-119 (Feb. 1989) The article describes an automated radio-wave instrument for measuring the dielectric permeability and thickness of dielectric sheet operating in the millimeter range of wavelengths. The sensor of the instrument consists of two different types of dielectric waveguide; this ensures the possibility of measuring simultaneously the permeability and thickness of specimens including those placed on a metallic base. The article deals with the principal features of the algorithm for processing signals and for calculating for parameters of the specimens.

Konev, V.A.; Mikhnev, VA. Frequency method of dielectrics testing in a microwave range

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Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1637-1639. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. A novel method for measuring the dielectric constant of low-loss slabtype materials at microwave or millimeter wavelengths is described. The determination is derived from measurement of frequencies corresponding to minima of a dielectric waveguide output, when the sample is placed near a curved section of the waveguide. The method requires only a small fiat area of the sample and is not very sensitive to gap variations. Therefore. it is well suited for practical applications, some results of which are presented.

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Konev, V.A.; Lyubetsky, N.V.; Tikhanovich, S.A. Non-destructive testing of materials by microwave ellipsometry methods

Symposium on Nondestructive Monitoring of Materials Properties, Boston, Massachusetts (United States), 28-30 Nov. 1988. pp. 335-340. Edited by J. Holbrook and J. Bussiere, MRS (1989) The presence of chloride ions in New England bridge decks has caused severe damage and has contributedgreatly in reducing service life.The source of the chlorideions is mainly from deicingsaltsappliedfor snow and ice removal to enable safer driving during the winter. This paper introduces a means of utilizing ground penetrating radar as a viable nondeslruetive means of detecting areas of high chloride concentration in concrete bridge

Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Voi. 2, pp. 1630-1632. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. Novel microwave methods of non-destructive testing relying on ellipsometry in the frequency range and under the conditions of total internal reflection as well as on interference ellipsomenT are considered. The analytical laws underlying these methods are considered, experimental data are presented, microwave ellipsometers are briefly outlined and the results of their testing are discussed.

Lim, K.; Gress, D.L. Detecting areas of high chloride concentration in b r i d g e decks

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Each entry in NDT Abstracts consists of the serial number in the National NDT Centre Information Store for identification purposes; the title of the paper, book or report; the name of the author; the name of the source journal or document and the abstracts. Where necessary, author's names and the title of foreign journals have been transliterated into the Latin alphabet according to British Standard BS 2979 : 1958.

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Most papers listed may be obtained as loans or copies via local library or direct from Loans Department, British Library Document Supply Centre, Boston Spa, Wetherby, Yorkshire LS23 7BQ. Details of the British Lending Library's UK and International Services may be obtained from The Director, British Library Lending Division. Technical reports are also available from the Loans Department of the British Lending Library and in the USA from the National Technical

All entries are indexed in a computerized retrieval system, located at Harwell, which allows rapid searching of information relevant to any particular inspection problem. This service is available to both UK and overseas organizations through the National NDT Centre's Qualtis Subscription Scheme - further details are available from Phil Lawrence on Abingdon (0235) 433391. © 1994 United Kingdom Atomic Energy Authority

NDT&E International 1994 Volume 27, Number 6

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