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The technique described in this paper consists of the examination of surface strains in a metal component with optically sensitive material bonded to the component and the analysis of the photoelastic pattern produced under load by means of polarized light reflected from the surface of the metal. The original investigations cover in considerable detail the development of the technique and the results obtained, using the photoelastic materials Catalin 800, C.R.39, and the Marco Resin, S.B.26C, and S.B.28C, in conjunction with light alloy, magnesium and mild steel. The fundamental problem of producing good adhesion between the photoelastic material and the metal surface coupled with satisfactory light reflexion from the latter comprised the major part of the initial investigations. Results of the measurement of both elastic and plastic stress concentrations at holes in plates subjected to uniform tension are presented, together with a qualitative analysis of the effect on stress distribution of the variation of the pin to hole clearance in lugs. Owing to the fairly extensive nature of the original investigations it has only been possible to outline the more salient features of the work undertaken. The term ‘Metaplastic’ is suggested to describe concisely the use of compound specimens for the photoelastic applications considered.

NOTWITHSTANDING the fact that there exists a considerable amount of literature published in various forms on the subject of brittle lacquers and their applications to a multitude of diverse problems a brief resume of some of the general principles involved would seem not to be out of place.

Details are given of a simple extensometer with a gauge length of 0·50 in. which uses the mechanical interference of two sets of parallel straight lines as the means by which to measure displacement and hence strain. The interference effect exhibited by two pieces of Dufaycolor reseau placed in surface contact has been employed for development purposes since the reseau provides a convenient and ready‐made source of fine parallel rulings, after the removal of the photographic emulsion. Some of the related aspects of mechanical interferometry and its possibilities are discussed by way of introduction.

A PHOTOGRAPH of the fully developed crack pattern adjacent to the end bolts in a Perspex model of the rear spar root joint of the same blade is given in FIG. 35. Fatigue tests are to be undertaken on the metal prototypes of the front and rear spar joints in which modifications arrived at by the model tests will be incorporated.

THE application of cemented wires to determine the location of initial failure in static tests on large specimens has been investigated, among others, by R. W. Powell in 1946.

Tapered and Parallel Shank Specimens Tapered and parallel shank specimens were loaded in increments of 200 lb. up to about 1,300 lb., generally the maximum for both types.

The investigations have been primarily concerned with some of the practical problems associated with the metoplastic technique, they have in this respect attempted to solve some of these problems with the best means available at the time.

The calibration of brittle lacquer is an important part of the technique. The photograph, FIG. 10, gives some idea of the essentials of a cam operated cantilever beam bending rig with a steel beam in position, partially deflected; the equipment shown is in certain respects similar to an American apparatus the subject of U.S. Patent No. 2,310,845. FIG. 11 shows the typical formation of a crack pattern in an early type of cantilever calibration beam the dimensions of which are given in FIG. 12. The cracks observed may be grouped into two classes, the first incomplete cracks at A, distance L1 from the root, and the first complete crack at C, distance L2 from the root of the beam. Consistent results have been obtained using the mean position at B, corresponding to ×=1/2(L1 + L2) in. to compute the strain sensitivities of lacquers. The distance A to C, equivalent to (L1−L2.) in. is invariably quite constant for a given type of lacquer, and thickness of coaling, a typical relationship between dimension (L1−L2) in. and the thickness of a lacquer is illustrated by FIG. 13.

Public procurement provides a fertile ground for corruption in the Nigerian public sector. Reforms to create an effective public procurement system, which have been almost exclusively the governmentʼs affair, seem to be yielding insignificant results. Effective reforms to control corruption in public procurement systems must be sustainably participative and inclusive of all essential stakeholders in the society. Most importantly, the preconditions for achieving a sound public procurement system are integrity and commitment to good governance practices through the provision of welldesigned legislation and supporting regulations and review processes.

This paper investigates the location determinants of foreign investors and how the location decision‐making impacts on their knowledge transfer strategies. Survey data were collected in Yunnan, a southwest province of China. By examining two different sets of location factors at both the national and provincial levels, the research found that location factors at the provincial level, rather than at the national level, directly influenced foreign investors’ knowledge transfer strategies. The research also found that the support of Yunnan’s local government compensated for the underdeveloped endowment conditions of the province, significantly increasing knowledge transfer of foreign investors. The research suggests that foreign investors need to make appropriate location selection to efficiently exploit their ownership advantages. A well‐structured policy regime is required of host countries in order to encourage knowledge transfer by foreign investors.