摘要:

An exposition is given of recent advances in the theoretical analysis of circuits comprising sets of intercoupled nonlinear oscillators. Motivation for this work Motivation for this work has come from mathematical modelling of biomedical systems, particularly for the electrical activity of the gastrointestinal digestive tract. Over the past few years a matrix linearisation method has been developed and and applied to a wide range of structures comprising chains, arrays rings and tubes. Also, different coupling components including pure time delay and two types of van der Pol oscillator dynamics, have been investigated. Numerous mode patterns have been predicted and experimentally observed, and stability criteria established for a wide range of conditions. The multioscillator mode analysis entails a two-stage process comprising matrix mode decoupling followed by equivalent linearisation similar to the Krylov-Bogolioubov approach.

DOI:10.1049/ip-a-1.1983.0013

出版商:IEE    

年代:1983

数据来源: IET

摘要:

A network model for the representation of the general 3-dimensional electromagnetic field has been presented in previous publications. Solution of the network was performed by an all mesh variable method. A method is described in the paper for the solution of the linked network model in terms of a scalar potential in the magnetic part of the field, and the mesh currents in the electric part. The validity of the solution method is confirmed by a comparison of calculations with experimental results, for a full 3-dimensional problem. The new node-mesh method is shown to give rise to considerably less variables than the all mesh variable method for the solution of the linked-network problem. A comparison is also made between the number of variables required by the node-mesh method and that required by some other differential equation formulations of the 3-dimensional eddy-current problem.

DOI:10.1049/ip-a-1.1983.0014

出版商:IEE    

年代:1983

数据来源: IET

摘要:

Ocean thermal-energy conversion (OTEC) is a novel ‘alternative’ energy technology that has created much interest in a number of countries; namely, the USA, Japan, France, Sweden, Holland, India and, most recently, the UK. In particular, the first three of these have had programmes to develop the required technology. However, most interest has been centred in the USA, where the current hiatus in Federal funding provides a timely opportunity to assess progress. This paper offers a survey of the prevailing position there; outlining the outstanding technical and associated problems, and likely future developments. Non-US programmes are only mentioned to contrast them with the American position. At present, it does not appear that OTEC plants will be commercially viable on a widespread basis even in the tropics. This is particularly true of the larger plants (400 MWe, MWe = megawatts of electrical energy, the final output of a power station) towards which the American programme is ultimately geared. There does seem to be a strong possibility that small OTEC plants, around 40 MWe or less, can be commercial in certain circumstances. This would be possible when one or, preferably, more of the following conditions are met: (i) where a land-based rather than ‘at sea’ plant is possible, (ii) where alternative energy supplies are at a premium, i.e. islands or regions without indigenous energy supplies, and (iii) where conditions are such that an OTEC plant could operate in conjunction with either or both an aquaculture or desalination plant.

DOI:10.1049/ip-a-1.1983.0015

出版商:IEE    

年代:1983

数据来源: IET

摘要:

The proportion of women managers in engineering is even smaller than in many other sectors of employment but various initiatives are bringing about a gradual increase. The Women's Engineering Society, having some managers among its members and hoping to encourage more, takes stock of the current position and looks moderately hopefully towards the future.

DOI:10.1049/ip-a-1.1983.0016

出版商:IEE    

年代:1983

数据来源: IET