Surface wave techniques for the study of engineering structures and materials

A wire drive pulse echo method of measuring the spectrum of solid bodies described. Using an 's' plane representation, a general analysis of the transient response of such solids has been carried out. This was used for the study of the stepped amplitude transient of high order modes of disks and for the case where there are two adjacent resonant frequencies. The techniques developed have been applied to the measurenent of the elasticities of refractory materials at high temperatures. In the experimental study of the high order in-plane resonances of thin disks it was found that the energy travelled at the edge of the disk and this initiated the work on one dimensional Rayleigh waves.Their properties were established for the straight edge condition by following an analysis similar to that of the two dimensional case. Experiments were then carried out on the velocity dispersion of various circuits including the disk and a hole in a large plate - the negative curvature condition.Theoretical analysis established the phase and group velocities for these cases and experimental tests on aluminium and glass gave good agreement with theory. At high frequencies all velocities approach that of the one dimensional Rayleigh waves. When applied to crack detection it was observed that a signal burst travelling round a disk showed an anomalous amplitude effect. In certain cases the signal which travelled the greater distance had the greater amplitude.An experiment was designed to investigate the phenanenon and it was established that the energy travelled in two nodes with different velocities.It was found by analysis that as well as the Rayleigh surface wave on the edge, a seoond node travelling at about the shear velocity was excited and the calculated results gave reasonable agreement with the experiments.

A rationale for the optimisation by computer methods of the efficient use of metals and materials

The aim of the research project was to gain d complete and accurate accounting of the needs and deficiencies of materials selection and design data, with particular attention given to the feasibility of a computerised materials selection system that would include application analysis, property data and screening techniques. The project also investigates and integrates the three major aspects of materials resources, materials selection and materials recycling. Consideration of the materials resource base suggests that, though our discovery potential has increased, geologic availability is the ultimate determinant and several metals may well become scarce at the same time, thus compounding the problem of substitution. With around 2- to 20- million units of engineering materials data, the use of a computer is the only logical answer for scientific selection of materials. The system developed at Aston is used for data storage, mathematical computation and output. The system enables programs to be run in batch and interactive (on-line) mode. The program with modification can also handle such variables as quantity of mineral resources, energy cost of materials and depletion and utilisation rates of strateqic materials. The work also carries out an in-depth study of copper recycling in the U.K. and concludes that, somewhere in the region of 2 million tonnes of copper is missing from the recycling cycle. It also sets out guidelines on product design and conservation policies from the recyclability point of view.

Development of science and technology policy for Kuwait

The status of Science and Technology in KUWAIT has been analysed in order to assess the extent of the application of Science and Technology needed for the Country's development. The design and implementation of a Science and Technology Policy has been examined to identify the appropriate technology necessary to improve KUWAIT's socio-economic-industrial structures. Following a general and critical review of the role of Science and Technology in the developing countries, the author has reviewed the past and contemporary employment of Science and Technology for development.of various sectors and the existence, if any, of any form (explicit, implicit, or both) of a Science and Technology Policy in KUWAIT. The thesis is structured to evaluate almost all of the sectors in KUWAIT which utilise Science and/or Technology, the effectiveness of such practices, their policymaking process, the channels by which policies were transformed into sources of influence through Governmental action and the impact that various policy instruments at the disposal of the the Government had on the development of S & T capabilities. The author has studied the implications of the absence of a Science and Technology Policy in Kuwait by examining some specific case studies, eg, the absence of a Technology Assessment Process and the negative impacts resulting from this; the ad-hoc allocation of the research and development budget instead of its being based on a percentage of GNP; the limitations imposed on the development of indigenous contracting companies and consultancy and engineering design offices; the impacts of the absence of Technology Transfer Centre, and so forth. As a consequence of the implications of the above studies, together with the negative results from the absence of an explicit Science and Technology Policy, eg, research and development activities do not relate to the national development plans, the author suggests that a Science and Technology Policy-Making Body should be established to formulate, develop, monitor and correlate the Science and Technology Activities in KUWAIT.