pressure 0-34 MPA, with helium and nitrogen gases. A technique of nondestructive pressure measurements is proposed based on the results of this study.

41574 Silenius, M. Paper machine condition test Anglo-Finnish Joint Symposium on Advances in Non-Destructive Testing, Espoo (Finland), 9-11 May 1988, pp. 165-175. Edited by T. Astron. Technical Research Centre of Finland (VT'F) (1988)

Machine downtime in the Finnish paper industry is extremely expensive. To alleviate this problem an array of non-destructive techniques are advocated. Each stage in the paper making process has its own problems and suggestions for each are offered. Among the techniques used are optical inspection, magnetic particle tests, vibration monitoring and liquid penetrant testing.

41554 Rankin, D. An expert eye on machine health Electrical Review, Vol. 222, No. 8, pp. 19-20 (1989)

Prevention of failure in three-phase induction motors is vital as these are widely used in industries such as mining, oil production, petrochemicals and steel manufacture. Nondestructive techniques can be usefully employed to prevent or minimise downtime. Various on and off line testing techniques are noted together with their limitations.

41503 United Technologies Corp. Non-destructive test method using transient holographic analysis - comparing holograms of test items vibrated at different excitation levels with those of a difference item in the same conditions. European Patent No. 298,899 (11 Jan. 1989)

41181 Sculthorpe, B.; Johnson, K. Using vibration to assess reactor coolant pump integrity Nuclear Engineering International, Vol. 34, No. 417, pp. 59-61 (Apr. 1989)

With the increased awareness of potential reactor coolant pump shaft failures after cracks were identified at several plants, including Florida Power Corp's Crystal River 3 in early 1986, two U.S. Companies undertook a test programme involving vibration monitoring to confirm the integrity of all four pump shafts at St Lucie. This programme has now operated successfully for two years.

41178 Cech, J.; Exner, J.; Kriston, F. NDT measurement of internal stresses in grey-iron castings Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1318-1320. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989.

Internal stresses in grid-shaped stress-test grey-iron castings were measured by the strain-gauge drill-hole method. The stress-test castings were shaken out of moulds at various time intervals. On the basis of measuring the temperature field, an optimum time for shaking out was sought. The E-module, necessary for the calculation of internal stresses, was measured by different methods at several points of the casting. The ultrasonic measurement of the E-module can be regarded as optimum.

41143 Summerscales, J. Non-destructive testing of fibre-reinforced plastics composites Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1555-1560. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989.

The production of fibre-reinforced plastics (FRP) composites now exceeds one-million tonnes per annum in the USA alone. The materials are used in highly-stressed components and thus there is a need to confirm their structural integrity. This paper reviews the complete spectrum of NDT techniques practised for the examination of FRP composites.

41135 Amoco Corporation Method for acoustic reverberation removal U.S. Patent No. 4,796,237 (3 Jan. 1989)

Defects in cement in wellbores can be determined using this downhole tool. A transducer within the tool transmits pulses of acoustic energy. The time delay (DELTA t) between transmission of a pulse and the reception of the first acoustic reverberation is measured. Positive and negative pulses of energy are used to establish a reverberation pattern.

40910 Berry, D.J.; Everett, G.M. Recent advances in instrumentation for experimental stress analysis and vibration analysis Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 588-593. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989

This paper traces the historical development of the thermoclastic effect as a stress measuring technique, together with its incorporation into commercially available instrumentation. This instrumentation is now widely used to validate designs and to assess the condition of components which have been subjected to service loading. A laser interfcrometcr option has recently been added to the instrumentation package, permitting vibration as well as stress data to be collected. Both sensor options share common data processing and scan control facilities to offer a comprehensive full field, non-contacting measurement capability. The paper presents industrial applications of both sensor options.

40784 Runkel, J.; Stegemann, D. Non-destructive condition monitoring of nuclear power plants by use of vibration analysis Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 628-633. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989

Information about the core behaviour and the operating conditions of the primary loop of nuclear power plants can be obtained by noise analysis of the standard reactor instrumentation signals. Generally four different kinds of problems are considered; surveillance of the integrity of the detectors and the signal transmission system, of mechanical conditions of the core and primary loop assemblies of thermohydraulic and monitoring and trend analysis of nuclear parameters. Vibration analysis is an especially efficient tool of condition monitoring of all reactor internals as well as the reactor pressure vessel itself and the other components of the primary loop. Loose parts, fatigue of material, cracks or other defects and even some burn up conditions of fuel elements can be identified by vibration analysis using the standard power plant instrumentation. Periodical measurements during reactor operation enable early fault detection.

40783 Petrovich, V.I.; Kljuev, V.V. Vibrometry of energetic equipment Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 623-627. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989

In this paper, the problem of reliability improvement in vibration testing of energetic equipment is taken up. The descriptions of portable and stationary vibration equipment and the basic characteristics of metrology means are presented.

40781 Penny, R.L. The mechanics and design of a hardness tester Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 534-536. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989

This paper provides initial results of research and development on a hardness tester based on the principle of a bouncing indenter. The reasons for choosing this tester arc its easy portability for in-situ use as well as a rational design based on understanding of the mechanics of its application. A preliminary design is briefly described together with some results.

40780 Rudnitsky, V.A.; Nedbalsky, I.L A new hardness testing method for elongated products Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 521-523. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989

It is proposed to conduct hardness testing by continuously registering the time interval between successive collisions of an indentor executing self-excited oscillatory motions while scanning the product surface. This new method makes it possible to substantially increase measurement accuracy and output, compared to those made by the dynamic method which uses isolated measurements.

40779 Stegemann, D.; Reimche, W.; Sodmersen, U.; Vortriede, A.; Beermann, H.; Scheer, G. Non-destructive condition monitoring of rotating machinery by vibration analysis Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands) 23-28 Apr. 1989, Vol. 1, pp. 518-520. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989

Computerized systems for multichannel vibration signal acquisition and processing, data presentation and pattern recognition have been developed and applied for condition monitoring of rotating machinery in order to detect inscrvicc damages by fatigue, corrosion and erosion. Special features of the systems are the introduction of synchronized triggering for data evaluation. Furthermore correlation techniques are applied -besides the wellknown spectral analysis techniques -to improve the detectability and identification of defects, in particular blade failures, defects of shafts, bearings, couplings and auxiliary equipment; contact between blades and casing as well as between shaft and labyrinth seals.

40729 Power Reactor & Nuclear Fuel Development Corporation Testing structures by inducing and detecting vibrations British Patent No. GB2201777 (7 Sop. 1988)

A structural defect detecting system is disclosed, which comprises vibration exciters and vibration sensors removably attached in a spaced arrangement to the construction to be inspected and by which vibratory waves generated by the vibration exciters propagate through the construction and are detected by the vibration sensors. These are analyzed to detect a defect or fault in the construction. The vibration exciters are piezoelectric accelerometcrs, which are excited by pulsed signals generated by a vibration signal generator and thus utilized as a vibration excitation source. The signal analysis components include a six channel amplifier, an eight channel data recorder, selectors for selecting on-line or off-line mode and passing data to a fast fourier transform circuit a controller and a plotter. Applications to chemical plant and nuclear power plants are referred to.

40399 Robertson, 1. T. Data handling and prediction for the health monitoring of helicopters

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