In 1765, Boston artist John Singleton Copley sent Boy with a Squirrel—a portrait of his half-brother Henry Pelham—across the Atlantic Ocean; the painting ended up in the hands of London-based artists Joshua Reynolds and Benjamin West. Because the work did not depict a patron and it was intended for an artistic audience, Boy with a Squirrel challenges the functionality of traditional portraiture in mid-eighteenth century colonial America. In Boy with a Squirrel, Copley uses form, iconography, and composition as a way to assert to his English counterparts his belonging to the London art community, showcasing his knowledge and even mastery of British and continental traditions. Copley communicates his membership in the London art public through his use through the formal lexicon of his desired audience, effectively Anglicizing his forms. While Anglicization plays a central role in the emergence of the public self in the mid- eighteenth-century American colonies, Copley's adaptation of Anglicizing forms challenges many of the standard conventions. Though the exchange of information between Britain and the American colonies was slow and incomplete, Copley would have had many different opportunities to learn about the British and continental traditions he hoped to demonstrate. The circulation of books and prints, the display of private collections, John Smibert's copies of masterworks, and the growing awareness of the Grand Tour all would have informed Copley's awareness of these British tastes. / text

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The ideal squirrel cage motor should have a varying rotor resistance; large at standstill, and decreasing as the speed rises. Overseas - designed high impedance rotors try to fulfil these conditions - mostly used are double cage rotors and die cast aluminium rotors. However, in the South African coal-mining industry these rotors recorded high rate failures with heavy financial losses. As a result, the need for an alternative rotor type that was able to comply with basic conditions ignored before appeared on the market: • Higher reliability with extended life expectancy • Lower total ownership costs • Easy re-manufacturing with components available on the market • Specific performance stability at competitive price. Over the years, only two principles were tacitly accepted in designing squirrel cage rotors: 1. For a single cage rotor, in a circumferential direction around the rotor the squirrel cage bars are placed in the same cylindrical shell, with the same shape and same conductivity. 2. For a double cage rotor, the same rule as above applies; however, in the radial direction, the bars have different shapes and typically different conductivities. The Invention is based on a new principle, i.e. "in a circumferential direction around the squirrel cage rotor, squirrel cage bars may have different conductivities and same shapes, or different conductivities and different shapes”. Mixed Conductivity Fabricated Rotors (MCFR) are designed and manufactured based on this new principle, and are able to withstand the harsh South African mining conditions. Since patented, the invention has been materialised in a set of special rotors powering continuous miners of a reputable coal-mining house, which was spending about R5 million annually on replacing specific imported die cast aluminium rotors only. Fully complying with the above-mentioned basic conditions, the patent offers a large variety of technical and economical advantages, increasing mining processes efficiency beyond expectations. The thesis describes the MCFR's design adaptability by altering the rotor design to meet the demands of a specific engineering application as a base line of drives design. The patent is part of the new South African trend of increasing processes efficiency. It offers large possibilities of designing dedicated motors with a positive impact on the South African economy. Some socio-economical advantages are worthy of considerable study: • Being locally manufactured, the MCFR may reduce the country's economical dependence. • Requiring no special expertise, the MCFR can be produced in any quantity and size without excessive investment. • The MCFR offers an alternative option (product interchangeability) on the market as well as sound competition (with export potential). • The patent ensures business sustainability conditions which diffuse financial constraints on motor manufacturers and end-users during the re-capitalisation process (very loaded in South African economic and industrial environment). / Thesis (Ph.D. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2007.

Thesis (PhD)--University of South Australia, 1999