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Rationale Many antipsychotics cause orthostatic hypotension possibly due to antagonist action on resistance vessel α1A-adrenoceptors (α1A-AR). Objective We have tested this possibility by determining in Wistar rats how the orthostatic hypotensive effect of several antipsychotic drugs compares with their affinity for adrenoceptors in mesenteric small arteries (MSA with mainly α1A-AR) and aorta (mainly...
Multiple generator transformer failures at the Eskom Lethabo power station caused the situation whereby the only available spare transformers had a secondary voltage of 400 kV. The only practical solution was to upgrade the existing 275 kV integration to the national grid to 400 kV, within a time constraint of three months. The 275 kV Lethabo-Glockner 1 and 2 lines were earmarked for the uprating...
Elaborate plans are presently being considered for long distance HVAC and HVDC lines along the length of the African continent. Optimising such lines covering both the electrical and mechanical design from an economical and technical point of view is not only important but also a challenge. Evaluating the design with software modelling is still the most cost effective option. Software packages, meeting...
Cost effective higher current rated power electronic technology makes possible the conversion of high voltage alternating current circuits for high voltage direct current employment. This strategy is promoted so as to yield greater power transfers by using the same physical power line and installed conductor cross sectional area. This idea was shared and discussed by study committee B4 at the 2004...
Early indications are that HVDC will be the technology of choice for the transmission interconnection into Africa. The dominant reasons being the quantities of power to be transferred, the length of the interconnection and the minimising of heating losses. Thus far the highest operational voltage used is the plusmn 600 kV Brazilian Itaipu system. For economical bulk power transfers over several thousand...
Continuous changes in the cost of suitable (conductive) material for bare overhead conductors, changes in electrical and mechanical requirements, and improvements in manufacturing technology, have resulted in the development of a variety of possible applications or options for overhead transmission lines. In the early days, simple copper wire or copper based bare conductors were used but nowadays,...
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