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As a result of a badly conceived farm policy the bulk of the EC′s dried grape crop of 1981/82 was sold into intervention. Minimum import prices (MIPs) were introduced, throwing the import trade into confusion, and distorting the market for dried grapes. MIPs meant that the competitive advantage of low cost suppliers was lost, and the importer′s traditional skills of buying cheap were thwarted. Failure to distinguish between types of product, quality and presentation, led to further difficulties. Even marginal failure to respect the MIP led to the application of substantial countervailing charges. In February 1988 a ruling of the European Court gave some relief to the beleaguered trade.

A Description of the Facilities Available in the Research Division of High Duty Alloys Ltd. and an Account of the Work Carried Out in Developing the Hiduminium‐RR.58 Alloy which has been Specified for the Anglo‐French Concord Supersonic Airliner. A brief account of the research work necessary for the development of aluminium alloys with special properties, in particular Hiduminium‐RR.58, the alloy which was initiated and developed by Dr W. M. Doyle and his colleagues and has now been specified by both the British and French designers for the construction of the B.A.C./Sud Concord supersonic airliner.

The authors construct an intertemporal model of rent-maximizing behavior on the part of a timber harvester under potentially multidimensional risk as well as geographical heterogeneity. Subsequently, the authors use recursive methods (specifically, the method of stochastic dynamic programing) to characterize the optimal policy function – the rent-maximizing timber-harvesting profile. One noteworthy feature of their application to forestry in the province of British Columbia, Canada is the unique and detailed information the authors have organized in the form of a dynamic geographic information system to account for site-specific cost heterogeneity in harvesting and transportation, as well as uneven-aged stand dynamics in timber growth and yield across space and time in the presence of stochastic lumber prices. Their framework is a powerful tool with which to conduct policy analysis at scale.

The use of fibre optic sensors is a relatively new development but the future applications are enormous

Insulating spheres for tanks. The new Allplas sphere (Fig. 1) is claimed to possess several advantages over the firm's existing sphere. The spheres are blow‐moulded from polypropylene, which is used to penetrate into the joint between the two halves of the mould, thus forming a circumferential flash on the old type of sphere, this flash being formed at the expense of wall thickness at that point. In contrast, the new sphere has a bead along the joint line, this providing reinforcement at what used to be the weakest point and thus greatly improving the resistance to mechanical damage.

THE British aircraft industry will only survive if it is competitive in the world's markets. This applies in both the civil and military fields. Since the main function of an aeroplane is to provide the most economic means of transportation — or weapons system — any symposium on any manufacturing technique must regard the value of engineering aspect as paramount. Thus, R. & D. into welding is not just a pleasant academic exercise and it must be justified by its ability to provide more economic aircraft.

THE development of synthetic resin adhesives has proceeded very fast since about 1937 when the first urea formaldehyde wood glues were being produced on a pilot scale. The excellent resistance of these materials to weathering conditions has enabled very considerable advances in structural design both in wooden structures and rather more recently in metal aircraft. These synthetic resin adhesives are basically ‘thermosetting’, that is to say, they harden by the addition of catalysts or by the application of heat, the chemical process which takes place being irreversible and not dependent upon the evaporation of solvents. This concept leads not only to good weather resistance, but also to the practicality of sticking together non‐porous materials such as metal. The first use of bonding of mstal in aircraft structures was in the de Havilland Hornet in 1943,1 and since then bonding has proved its advantages over other methods of joining for both primary and secondary structures. Other new methods of fabrication have appeared since that time and the requirements for structures in terms of loading and environment have changed considerably; but both mctal‐to‐metal bonding and its newer partner honeycomb sandwich show signs of much more extensive use in the future. These two most important applications of synthetic resin adhesives in modern aircraft will now be considered.

DURING the spring of 1968, Pilot magazine initiated the design of a homebuilt aircraft. The intention was to follow through the design in a series of articles highlighting the problems, difficulties and, hopefully, successes of the project. The initial design was undertaken by the staff of the magazine defining the basic specification of the aircraft as a two‐place, all‐metal tourer/sports plane of modern style, capable of 5 hours' endurance, and arriving at the aircraft shown in Fig. 1. It is a sensibly small aircraft of 24ft. wing span and 20 ft. overall length with a constant 4 ft. wing chord to give a gross wing area of 96 sq. ft. The cockpit area, covered with a one‐piece sliding canopy, is a generous 48 in. wide with ample leg room forward and luggage space aft.

This paper proposes the Student's t Dynamic Linear Regression (St-DLR) model as an alternative to the various extensions/modifications of the ARCH type volatility model. The St-DLR differs from the latter models of volatility because it can incorporate exogenous variables in the conditional variance in a natural way. Moreover, it also addresses the following issues: (i) apparent long memory of the conditional variance, (ii) distributional assumption of the error, (iii) existence of higher moments, and (iv) coefficient positivity restrictions. The model is illustrated using Dow Jones data and the three-month T-bill rate. The empirical results seem promising, as the contemporaneous variable appears to account for a large portion of the volatility.

AEROSPACE is a very broad field and in order to deal with sheet metal applications in a little detail it is proposed to limit this article to airframes where the largest usage of sheet metal occurs.