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Article
Publication date: 1 July 1959

D.E. Clippinger and G.J. Morris

THE use of liquid oxygen as an oxidizer for various fuels in liquid rocket propellent systems is not new. Professor Goddard used liquid oxygen in his rocket experiments and the…

45

Abstract

THE use of liquid oxygen as an oxidizer for various fuels in liquid rocket propellent systems is not new. Professor Goddard used liquid oxygen in his rocket experiments and the well known German V‐2 rockets used this material as an oxidizer. However, its effect on non‐metallic materials ordinarily used in rocket systems was not investigated until recent years. This investigation was prompted by phenomena which had been experienced by rocket engine and rocket aircraft manufacturers and by suppliers of the material. It was observed that when some organic materials came in intimate contact with liquid oxygen they became prone to detonation when subjected to certain impact energies. This was undoubtedly due to the formation of unstable organo‐peroxide compounds which when impacted released high levels of energy resulting in an explosion. Specifically, when liquid oxygen was accidently spilled on asphalt and inadvertently stepped on, the asphalt would often explode. Also, leather gaskets immersed in liquid oxygen and subjected to surge impact detonated with disastrous effects.

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Aircraft Engineering and Aerospace Technology, vol. 31 no. 7
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 January 1992

Tamasz Zoodzinski

In the paper the optimization procedure of a direct current motor with a hybrid excitation has been presented. The excitation system consists of a shunt field winding disposed…

42

Abstract

In the paper the optimization procedure of a direct current motor with a hybrid excitation has been presented. The excitation system consists of a shunt field winding disposed around field pole and permanent magnet, both acting in parallel. The field distribution in motor for various magnet and field pole dimensions has been determined using finite element method. The flux linkage with the armature winding has been computed. Demagnetizing effect of armature current was taken into account. The optimal permanent magnet and the field pole dimensions, ensuring minimum total cost of purchase and work during assumed period of time were calculated. Motor characteristics e.g. rated torque, rated current, speed regulation limit were used as constraints. In worked up algorithm and computer program Carroll internal penalty function method was used. Some basic suggestions tor design of optimal hybrid excited dc motors with parallel permanent magnet and electromagnetic excitation are given.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 11 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 April 1991

K. Horio and H. Yanai

I‐V characteristics of GaAs n‐i‐n structures are calculated by considering impact ionization of carriers. Impact ionization at reverse‐biased n‐i junction becomes a cause of steep…

38

Abstract

I‐V characteristics of GaAs n‐i‐n structures are calculated by considering impact ionization of carriers. Impact ionization at reverse‐biased n‐i junction becomes a cause of steep current rise when an acceptor density in the i‐layer is high. It is shown that an optimum acceptor density exists to keep a good isolation. Photoconduction transients of GaAs n‐i‐n structures are also simulated, and are shown to be strongly affected by existence of n‐i junctions.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 10 no. 4
Type: Research Article
ISSN: 0332-1649

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Publication date: 1 April 1986

Michal Polácek

In the course of development of human communities towards industrially advanced societies of today, there have been changes not only in economic conditions in the majority of…

280

Abstract

In the course of development of human communities towards industrially advanced societies of today, there have been changes not only in economic conditions in the majority of fields of human activity but also in the ways of providing for food, which went hand in hand with changes in living conditions. Large‐scale industrial production has brought about major changes in the way of life of the population. The development of industrial agglomerations results in a growing number of city dwellers, most of whom have no chance of producing foodstuffs of their own in kind. The distance between residential and industrial areas has been growing, the number of employed women has risen considerably. These are but a few factors affecting the way of boarding, particularly in households.

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The Tourist Review, vol. 41 no. 4
Type: Research Article
ISSN: 0251-3102

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Article
Publication date: 1 October 1969

John Duke

‘The application of computers to teaching and learning is a logical development in the evolution of educational technology, although at present the ultimate benefits can be but…

31

Abstract

‘The application of computers to teaching and learning is a logical development in the evolution of educational technology, although at present the ultimate benefits can be but dimly foreseen. The realization of this potential will require concentrated research and development efforts which can only profitably flourish within the ambit of a national programme of work.’ So opens a recently published report of the National Council for Educational Technology addressed both to Ministers and to all engaged in the education industry. What lies behind this bald statement with its overtones of brash prophecy, veiled threat, and blatant jingoism? I would like to explore some of the reasons for thinking that a revolution in education, as far reaching as the Copernican revolution in astronomy, is now within the realm of possibility.

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Education + Training, vol. 11 no. 10
Type: Research Article
ISSN: 0040-0912

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Article
Publication date: 1 March 1989

Scott W. Kelley

Explains that efficient service delivery can often present aproblem for marketers due to the nature of the services. Summarizes thetwo general methods already suggested for…

1418

Abstract

Explains that efficient service delivery can often present a problem for marketers due to the nature of the services. Summarizes the two general methods already suggested for improving the efficiency of service delivery – technological and humanistic. Discusses managerial guidelines for the implementation of these approaches to service delivery in several service industries, based on two service classification schemes.

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Journal of Services Marketing, vol. 3 no. 3
Type: Research Article
ISSN: 0887-6045

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Article
Publication date: 1 April 1976

W.B. Heginbotham, A. Pugh, D.W. Gatehouse and D. Law

The realisation of a practical generally versatile variable product assembly machine is still far from reality. However, in the same way that a generation 1 Industrial Robot can…

22

Abstract

The realisation of a practical generally versatile variable product assembly machine is still far from reality. However, in the same way that a generation 1 Industrial Robot can achieve high levels of versatility within certain restricted activities e. g. paint spraying ‐ spot welding etc., then by the correct choice of product and product design high levels of versatility can be achieved with assembly machines.

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Industrial Robot: An International Journal, vol. 3 no. 4
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 1 May 1985

Michael G. Allen

Strategic management—the infusion of strategic principles in the running of a business—has demonstrated impressive power by dramatically improving the performance of a number of…

148

Abstract

Strategic management—the infusion of strategic principles in the running of a business—has demonstrated impressive power by dramatically improving the performance of a number of major companies that implemented it. (See Exhibit 1.) This concept, born in the early Seventies, is now experiencing the adolescent struggles of what Gail Sheehy, the author of Passages, calls, “gaining authenticity” and “ego strength.” Now, an era of self assurance, authority and leadership is at hand.

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Planning Review, vol. 13 no. 5
Type: Research Article
ISSN: 0094-064X

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Article
Publication date: 1 June 1939

F.H. Gribble

THE rapid growth and development of the aircraft industry has necessitated prompt decision and action in handling the many problems in connexion with the erection and equipment of…

58

Abstract

THE rapid growth and development of the aircraft industry has necessitated prompt decision and action in handling the many problems in connexion with the erection and equipment of aerodrome buildings, hangars, workshops and factories. In the urgency of providing the industry with all its varied requirements, it is not surprising that lire insurance planning has to a very large extent been crowded out. There are, no doubt, several reasons for this and in the welter of plans and designs that have been drawn and re‐drawn, the necessity of complying with the clients' requirements, numerous rules and regulations of local authorities and Acts of Parliament, etc., the benefits which accrue to wise planning from a fire insurance point of view have not always been fully appreciated. The need for increased output has in many cases pressed very heavily on those making the necessary preparations, and frequently no serious thought has been given to fire insurance planning. There are some persons who are under the impression that, having conformed with the numerous rules and requirements, they have carried out all that can be done in this direction.

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Aircraft Engineering and Aerospace Technology, vol. 11 no. 6
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 23 August 2024

Wenling Wang and Caiqin Song

The paper aims to study the constraint solutions of the periodic coupled operator matrix equations by the biconjugate residual algorithm. The new algorithm can solve a lot of…

28

Abstract

Purpose

The paper aims to study the constraint solutions of the periodic coupled operator matrix equations by the biconjugate residual algorithm. The new algorithm can solve a lot of constraint solutions including Hamiltonian solutions and symmetric solutions, as special cases. At the end of this paper, the new algorithm is applied to the pole assignment problem.

Design/methodology/approach

When the studied periodic coupled operator matrix equations are consistent, it is proved that constraint solutions can converge to exact solutions. It is demonstrated that the solutions of the equations can be obtained by the new algorithm with any arbitrary initial matrices without rounding error in a finite number of iterative steps. In addition, the least norm-constrained solutions can also be calculated by selecting any initial matrices when the equations of the periodic coupled operator matrix are inconsistent.

Findings

Numerical examples show that compared with some existing algorithms, the proposed method has higher convergence efficiency because less data are used in each iteration and the data is sufficient to complete an update. It not only has the best convergence accuracy but also requires the least running time for iteration, which greatly saves memory space.

Originality/value

Compared with previous algorithms, the main feature of this algorithm is that it can synthesize these equations together to get a coupled operator matrix equation. Although the equation of this paper contains multiple submatrix equations, the algorithm in this paper only needs to use the information of one submatrix equation in the equation of this paper in each iteration so that different constraint solutions of different (coupled) matrix equations can be studied for this class of equations. However, previous articles need to iterate on a specific constraint solution of a matrix equation separately.

Details

Engineering Computations, vol. 41 no. 7
Type: Research Article
ISSN: 0264-4401

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