The eyeball ROV: Design and control of a spherical underwater vehicle steered by an internal eccentric mass

A Remotely Operated Vehicle (ROV) is developed for use in the inspection of underwater structures in hazardous environments. The vehicle presented can change orientation like an eyeball using a novel gimbal mechanism for moving an internal eccentric mass. Combined with a pair of thrusters, the Eyeball ROV can move in any direction with non-holonomic constraints. In this paper the design concept is presented first, followed by dynamic and hydrodynamic analysis. Due to poor open loop stability characteristics, stability a ugmentation is implemented using onboard sensors and was de signed and tested in simulation. A physical proof-of-concept prototype is also presented

Composite facies maps: a new aid to palaeo-environmental reconstruction

A new method is described whereby different types of stratigraphic and lithofacies maps can be integrated into a single coherent map. The end product contains an accumulation of features identified in the individual base maps, thereby simplifying the interpretation and recognition of trends. Depending on the number of maps employed, a specific standard value is allotted to each original map and its data are normalized so that every map has the same range of values. The new values for each data point are then added to give compound dimensionless values, which are contoured to produce a composite facies map. The method is illustrated by means of an example from a uranium-bearing braided river deposit in the Beaufort Group. Four conventional map types are combined in order to reconstruct the palaeo-environment. -from Author

The first Lower Palaeozoic fauna proved from South Africa

[No abstract available]A fauna is described from the Cedarberg Formarion of the Table Mountain Group, western Cape Province. New taxa of brachiopods are Trematis taljaardi sp. nov., Marklandella africans sp. nov., Eostropheodonta discumbata sp. nov., and Plectothyrella haughtoni sp. nov. These indicate an age close to the Ordivician-Silurian boundary. This is the first Lower Palaeozoic fauna to be found in Africa south of the Sahara.Not

The first Lower Palaeozoic fauna proved from South Africa

[No abstract available]A fauna is described from the Cedarberg Formarion of the Table Mountain Group, western Cape Province. New taxa of brachiopods are Trematis taljaardi sp. nov., Marklandella africans sp. nov., Eostropheodonta discumbata sp. nov., and Plectothyrella haughtoni sp. nov. These indicate an age close to the Ordivician-Silurian boundary. This is the first Lower Palaeozoic fauna to be found in Africa south of the Sahara.Not