ND T Abstracts outer surface of the pipe specimen. Experimental procedures are described and results presented. 41736 Lingard, S; Ng, K.K. An investigation of acoustic emission in sliding fraction and wear of metals Wear, Vol. 130, No. 2, pp. 367-379 (Apr. 1989) Measurements of acoustic emission (AE) in severe sliding of metallic specimens were performed with a view to determining relationships, if any, between AE and wear-friction parameters, it was found that AE is readily observed in dry sliding and that emission rates and cumulative count data are sensitive to the external variables which influence tribological contact conditions. A relationship between cumulative AE count and frictional work is proposed and possible reasons for the form of the relationship are discussed. Emissions did not appear to he directly dependent on rates of wear but the possibility that AE-wear correlations exist should not be precluded in view of recent work in other laboratories using significantly different apparatus and instruments. 41713 Frederikse, H.; Feldman, A. T h e r m a l wave inspection of heat resistant ceramic coatings Nondestructive Testing of High-Performance Ceramics, Conference Proceedings, Boston, Massachusetts, (United States), 25-27 Aug. 1987, pp. 177-182. Edited by A. Vary and J. Snyder. The American Ceramic Society (1987) Photo-thermal radiometry is being evaluated as a non-contact method for on-line monitoring of the thermal resistance of ceramic coatings. Measurements have been made on plasma sprayed-coatings of chromia and zirconia. Thermal conductivities of the coatings appear to be two to five times smaller than for bulk materials. 41712 anon T e m p e r a t u r e - b a s e d t h e r m o g r a p h i c inspection technology Verfahrenstechnik, Vol. 23, No. 6, pp. 53-54 0un. 1989) An industrial thermography system with computerised data evaluation is described. The rechargeable battery-powered thermograph weighs a little over 6 kg and is similar to a video camera in operation, with data recording on to a built-in 3 1/2" rustproof diskette holding 0.7 M of data. The complete unit is designed for use in situ at industrial plant such as furnaces. For subsequent processing of the diskettes there is a special software package CM ("Condition Monitoring") with several versions and highly developed colour graphics. The measurement range is -20 to +500sup(o)C without loss of accuracy by using a flame filter. The thermograph can work in electromagnetic fields and observe gas combustion processes (filtering out irrelevant spectrum components).
Sattler, F,I. Improving quality through nondestructive testing 41555
Chemical Engineering, Vol. 96, No. 4, pp. 116-119 (Apr. 1989) This review describes the role of nondestructive testing (NDT) during specification and procurement as well as in preventative maintenance. Various NDT techniques are noted with their mode of operation and limitations. The author concludes by describing NDT as it is used for monitoring processoperations. 41551
Berdonosov, V.A.; Boiko, D.A.; Lapshin, B.M.; Chakhlov,
V.L. Nondestructive inspection of the condition of oil pipeline cleaning units Soviet Journal of Nondestructive Testing, Vol. 24, No. 6, pp. 428-431 (Feb. 1989) A reduction in downtime in main oil pipelines can be achievedusing a combination acoustic and radiographic method. Stoppageof the cleaning units is very common. Theseare locatedusing acousticmeansi.e. increased acoustic noise at the point of stoppage. Inspection of the condition of the cleaning unit is conductedradiographic,ally. This devicemakesit possibleto prevent emergencysituations without dismantling the pipeline. 41541
Blum, T.; Suzuki, L;/nasaki, L
systems for the detection of single-point and multipoint cutting tool failures Journal of Acoustic Emission, Vol. 7, No. 4, pp. 179-184 (Oct.-Dec. 1988) This paper presentstwo acoustic emission (AE) monitoring devices to evaluate the condition of single-point and multipoint cutting tools. The differing primary dynamic characteristics of single-point and multlpoint machine tools create several problems. Reliable detection of "in-direct" signals which are associatedwith the machining process is highlighted in this study.
41507 Koyo Seiko KK (Kawi) Acoustic monitor for detecting early stage of damage in bearing - measures power of acoustic emission from bearing and compares hand- passed output with given threshold to determine failure rate European Patent No. 297,729 (4 Jan. 1989) 41338 Hopwood, T.; Prine, D.W. Acoustic emission monitoring of in-service bridges Kentucky Transportation Research Program, Lexington (United States), PB88-244231/GAR, 61 pp. (Aug. 1987) An experimental acoustic emission (AE) device, the Acoustic Emission Weld Monitor (AEWM), has been field tested on six bridges during the study. In addition, the device was used to test three other bridges under separate contracts from state highway agencies. The device was evaluated to determine if it could detect fatigne-crack growth on in- service steel bridges. The device rejects high background noise rates typical of bridges and detects and locates AE activity from known defects such as cracks and subsurface flaws. The AEWM functioned properly in every field test situation to which it was applied. The device has demonstrated capability to perform AE tests on inservice bridges. It may be used to detect hidden defects or to assist in making repair decisions concerning detected discontinuities. The AEWM and AE testing have the potential for low-cost inspection of critical bridge members. 41335 Buttle,D.I.; Scruby, C.B. Acoustic emission monitoring of a fatigue crack in 50D steel in a sea- water environment NDT International, Vol. 22, No. 2, pp. 81-96 (Apr. 1989) Four specimens of 4360-50D steel plates were fatigued under a range of simulated marine environments and loads. Acoustic Emission (AE) events were detected using four broadband point-contact u'ansducers and located in 3D ( <1 mm accuracy) relative to the crack front. This information was used together with the load at which each emission occurred to distinguish between 'primary' and 'secondary' source events. The results are presented and discussed. Measurements of the compressional wave arrival strengths at each probe were compared with calculated radiation patterns for different types of AE source. The experimental radiation patterns were always consistent with a double monopole combined with a microcrack source in varying proportions. Under these testing conditions, secondary events associated with corrosion product fracture dominated the emission. Whilst little or no primary emission was detected during fatigue crack growth in parent plate, this may not be the case in welds, regions of low toughness or where the stress fields are more complex. 41138 Prasad, R. Acoustic emission - its industrial applications Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Voi. 2, pp. 927-929. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989. The paper describes the use of continuous monitoring of Acoustic Emission (AE) Signals for the study of events like phase transformation, stress corrosion, cracking of brittle surface coating, welding processes, tool wear, Cr-plating, leak detection, integrity of reactor pressure vessels, and off-shore structures, in-flight monitoring of air-craft structures, slope stability, onset of rock-fall and determination of fatigue life.
Industrial applications of near infrared reflectance for the measurement of moisture Measurement and Control, Vol. 22, No. 2, pp. 45-49 (Mar. 1989) Near infrared reflectance has been used increasingly in a wide variety of industrial applications to provide accurate process control using on-line sensors to provide continuous reliable signals relating to moisture content and is now recognized as a useful and powerful measurement technique. The theory behind the technique is discussed as is instrumentation and installation. Various industrial applications are discussed as examples such as milk powder, maize grit, nylon polymer chips, and cottage cheese. 40526 Tonolini, F. Application of acoustic emission to condition monitoring Proceedings of the 16th European Working Group on Acoustic Emission Conference, London (United Kingdom), 13-18 Sep. 1987, pp. 2951-2960. Edited by C.B. Scruby and R. Hill, Proceedings of the 4th European Conference on Non-Destructive Testing, London (United Kingdom), 13-17 Sep. 1987, Voi. 4, Pergamon Press, 1988 In applying acoustic emission (AE)technology to condition monitoring, both the phenomena producing AE in the materials and the acoustic
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