Proximity and complexity in the emergence of high technology industry: The oxbridge comparison

This paper examines similarities and differences in the emergence of high-tech enterprise and the growth of associated industry in Cambridgeshire and Oxfordshire since the 1960s. These cases are viewed as instances of a generic phenomenon: the emergence and growth of the science-based ‘innovative milieu’. A conceptual scheme drawn from complexity studies is used to introduce explanatory coherence into the apparently scattered and disconnected factors relevant to the genesis of high-tech milieux.     

Properties of the 20-node brick

Three-dimensional elastoplastic analyses are increasingly feasible as computing power increases. Candidate finite elements for this work are 20-node bricks. In elastoplastic situations, yielding creates ‘soft’ regions within a stiffer surrounding matrix and propagation of spurious modes is possible under reduced integration. In this paper, the intrinsic properties of the 20-node brick are analysed, with a view to avoiding numerical complications in plasticity analyses.     

The 1988 Orange River flood, Upington Region, Northwestern Cape Province, RSA

This paper describes aspects of the 1988 Orange River flood. The Orange River is a perennial, bedrock-controlled river which experienced severe flooding (flood peak: 8300 m³ s^-1) during February-April of 1988. This flood resulted in the loss of life and damage in excess of $126 million. Negligible bank erosion took place in the main channel margins due to the stabilizing effect of tree-lined banks. In contrast, areas removed from the channel margin were characterized by erosion and deposition. Within the confines of the natural flood channels, macroturbulence gave rise to scour holes which sometimes amalgamated into large erosion fields acres in extent. In many cases scour holes were present but macroturbulence-originating obstacles were not, and it is suggested that these were removed by flood-erosion processes. In some instances amalgamation of scour-hole trails (orientated down-current) led to the formation of steep-sided flood channels. Deposition took the form of large sandsheets constructed from fluvial-dune fields and braid-bar accumulations. Post-flood winds reworked some of the deposited sand into aeolian dunes.     

Refraction and scattering into a sandy ocean sediment in the 30-40-kHz band

To observe sound penetration into a sandy sediment, a buried acoustic receiving array was insonified by a wide band sound source carried by a remotely operated vehicle. A slanting array design was used to avoid scattering artifacts. This design overcame possible problems in previous experiments, in which scattering artifacts from the array structure could be mistaken for a propagating wave. The experiments took place in a sandy sediment off the West coast of Florida, as part of the sediment acoustics experiment, which is a multidisciplinary effort to study sediment acoustics. A coherent angle, speed, and height estimation process searched through a four-dimensional search space, of source height and elevation angle, wave speed, and propagation delay to find spherical acoustic wave fronts. Three main categories of waves were found: first refracted, dominant nonrefracted and evanescent. Later acoustic arrivals, a fourth category, remain to be analyzed. Their relative intensities effectively characterize the sediment penetrating acoustic energy. The acoustic sound pressure level of penetrating waves below the critical grazing angle was found to be greater than expected for a flat interface.     

Discrete element analysis of pile instability

Recently, instability of slender piles during installation has been analysed as a non-conservative buckling process. For these results to be of potential use in practice, simple procedures are necessary whereby piles of arbitrary cross-section installed in ground with arbitrarily varying properties can be treated. This paper lists discrete element matrices which enable the prediction of the onset of instability in piles assuming conservative or non-conservative ground resistance. The same matrices can then be used to incorporate effects of incipient instability in driveability analyses.