An energy policy for Australia: Extracts from the summary report and recommendations of the Task Force on Energy of The Institution of Engineers,Australia

Over the next few years, Australia must modify its dependence on natural oil and place greater reliance on other fossil fuels and renewable energy sources. The management of this transition is a major task, and can only be successfully achieved through a co-ordinated programme of action by Commonwealth and State Governments, supported by widespread public understanding of the issues involved.The recommendations in this report have arisen from the deliberations of the Task Force on Energy, which commenced work in 1975. The Task Force and its associated twelve working parties included many of the leading energy experts in Australia, in engineering, science and economics. They are associated with State Governments and energy instrumentalities, Commonwealth agencies, private enterprise, consulting engineering, universities and research bodies, but have co-operated in the work of the Task Force in their personal capacities. Overall, at least one hundred key specialists were associated with the working party studies. There was wide-ranging national co-operation in these studies, and information on critical energy issues throughout Australia was freely exchanged.     

Modeling and code development for concrete structures: An overview

The present status of efforts to model concrete behavior under projected extreme loadings suitable for finite element formulation is presented. The difficulties in modeling introduced by problems associated with quality control of the concrete mix and dependency of test results on a number of variables are pointed out. A variety of modeling schemes which attempt to take into account such peculiarities of concrete behavior are discussed, and advantages and shortcomings of each scheme are mentioned. Future analytical and experimental research needs are indicated, especially with regard to reinforced concrete element modeling. The present paper constitutes a state-of-the-art report on computer modeling of plain and reinforced concrete behavior and contains appropriate recommendations from the authors.     

On real factorizations of symmetric circulant sparse matrices

For the matricesA mentioned in the headline we determine the limit points up to which there is possible a real factorization of the formA=QQ ^T . HereQ=(q _ij ) is a circulant matrix, where from the elementsq _ij andq _ji withi≠j always one element is vanishing.     

Anregungen aus dem Schnittebenenverfahren für die Lösung des allgemeinen Transportproblems

If the cutting plane method is applied formally to the computation of flows with minimal costs then repeatedly negative cycles have to be determined. Up to now this can be done only with algorithms which are relatively clumsy. A modification of the algorithm enables us to avoid the search of such cycles and to generate an effective algorithm. At the same time we obtain stimulations for other numerical procedures, e. g., it becomes apparent how to proceed, when the approximation of the (nonlinear) cost function is successively improved.     

5.0 Nanosecond surface discharge development

Contents The nanosecond developing mechanisms of the positive and negative corona streamers on the insulation surface have been studied using the Dust figure technique (=Lichtenberg figure technique). This method has an advantage of measuring the velocity of corona discharge developments, because the distribution of the positive and negative charges produced in the discharge space can be colorfully separated and recorded on the insulation surface. The velocities of the corona streamer development were measured at the voltage of 821 kV and the pressure of 50760 Torr. From the result, the velocities obtained at a voltage of 21 kV and a pressure of 150 Torr were 8.2×10⁸ cm/sec in the positive and 5.8×10⁸ cm/sec in the negative. The observed maximum velocity of negative corona streamer was 1.0×10⁹ cm/sec at the conditions of 18 kV and 50. Torr. The result suggests that the velocity of the negative streamer will be larger than that of the positive at lower pressure and also nanosecond pulse voltage. Moreover, it was found that the field distribution in the corona streamer on the insulation surface could be estimated using Gauss's law.

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5.0 Nanosekunden—Oberflächen—Entladungsentwicklung

Übersicht Die Nanosekunden Ausbreitungsmechanismen der positiven und negativen Koronaentladung auf den Isolatoroberflächen sind mit der Staubfiguren-Methode (=Lichtenberg-Figuren-Methode) erforscht worden. Diese Methode hat einen Vorteil für die Messung der Ausbreitungsgesch windigkeit der Koronaentladung, weil die Verteilung der positiven und negativen Ladung, die im Entladeraum erzeugt wird, auf den Isolatoroberflächen sorgfältig getrennt und aufgezeichnet werden kann. Die Ausbreitungsgeschwindigkeit der Koronaentladung wurde bei einer Spannung von 5 bis 21 kV und einem Druck von 50 bis 760 Torr gemessen. Aus dem Resultat: Die Geschwindigkeiten, die bei einer Spannung von 21 kV und einem Druck von 150 Torr gemessen wurden, betrugen 8,2×10⁸ cm/sec in der positiven und 5,8×10⁸ cm/sec in der negativen Spannung. Die gemessene Höchstgeschwindigkeit der negativen Koronaentladung lag bei 1,0×10⁸ cm/sec bei einer Spannung von 18 kV und einem Druck von 50 Torr. Das Resultat ergibt, daß die Geschwindigkeit der negativen Koronaentladung größer wird als die der positiven Koronaentladung bei geringerem Druck und bei Nanosekunden-Impulsbreite. Darüber hinaus wurde festgestellt, daß die Feldverteilung in der Koronaentladung auf den Isolatoroberflächen mit Hilfe des Gausschen Gesetzes geschätzt werden konnte.

     

A O(|V|·|E|) algorithm for maximum matching of graphs

This paper presents an algorithm which finds a maximum matching in a graph withn nodes andm edges within timek ₁ mn+k ₂ , wherek ₁ andk ₂ are constants. It is also shown that a maximum degree-constrained subgraph can be found within timek ₃ m ³ +k ₄ , wherek ₃ andk ₄, are constants. Use of random access computer is assumed in the computation of the time bounds.