Summary form only given, as follows. An increasing number of electricity markets employing some form of spot pricing. However, limited experience of the behaviour of spot prices exists. This paper introduces and investigates one particular aspect of pricing behaviour observed in the New Zealand spot market, known as “price inversion”. Spot prices are generally calculated using some form of OPF or power-flow software. The phenomena of price inversion is investigated using the DC power-flow implemented in the New Zealand spot market, and using a full AC power-flow. Price inversion is shown to be dependent on the physical characteristics of the power system. The economic implications of price inversion are also discussed

Radar, both ship-borne and airborne played a vital part in preventing the defeat of Britain in the Battle of the Atlantic. The Telecommunications Research Establishment (TRE) was responsible for the airborne radar for the RAF and FAA. A detailed account of the work on the airborne detection of surface vessels, starting with the first experiments in 1937, is given in the paper. ASV (aircraft to surface vessel) started its life as an equipment intended for the detection of surface vessels. The importance of the submarine during the Second World War deflected attention, to a very large extent, from ASV's original role. As the war progressed more and more attention became focused on the improvement of the equipment to enable it to detect submarines with less and less showing above the surface of the sea.

The paper describes the Regional and National Tracing Systems being developed for the UK enabling public service records to be identified and located using unreliable and incomplete name and address information, and explains how CAFS provides an answer to a problem which would otherwise be insoluble. Topics covered include the sizing calculations, the main database organisation, the primary and secondary indexing structures and particular reference is made to the use of CAFS in 'fuzzy' and quorum searches.

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AbstractA brief account of the rheology course for undergraduates at the Procter Department of Food and Leather Science of Leeds University is given. Both the practical and theoretical approaches are considered. The former deals with present methods of rheological assessment, the latter should provide a sound foundation for future rheological research.

The many uses of leather have largely relied on the range of mechanical properties which it can provide, according to the raw material employed in its manufacture and the manufacturing processes themselves. The contrasting behaviour of a stiff sole leather and of a fine gloving leather exemplify this point. The last twenty years have seen intensive investigation of many mechanical properties of leather and the design of test methods now accepted internationally.

Summary An apparatus has been designed and constructed which allows the rupture properties of dilute gelatin gels to be studied. Breaking stresses in the range 1.7×104 to 1×106 dyne cm−2 have been determined; extension at break varied between 46 and 155%.

AbstractA vacuum still for lithium has been constructed and operated. Analysis of lithium before and after distillation shows a reduction of concentration of most elements except oxygen; however, the available methods of analysis for oxygen are not considered reliable. Precise details of operations and difficulties with the present design are included.It is concluded from the present work, and that of others, that purification of lithium to nuclear reactor standards is feasible.

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(1955). The Chemical Structure and Physical Properties of Gelatin. The Journal of Photographic Science: Vol. 3, No. 2, pp. 60-67.

FRACTIONATION1 commercial gelatins has shown that the rigidity of gelatin gels is not solely dependent on the distribution of molecular weights but also depends on another factor—the ‘rigidity factor’. Scatchard's results2 show that the mean molecular weight of gelatin, and also its viscosity in aqueous solution, are decreased by thermal degradation. Ferry3 measured the reduction in the rigidity of gels of these degraded gelatins, and related the changes to the molecular weights. The present investigation shows that while in certain conditions (for example, low pH) Ferry's assumption is correct, in other conditions (for example, neutral or high pH) the rigidity factor is also reduced as degradation proceeds.

AbstractA method for fractionating gelatin based on the solubility behavior of gelatin/detergent complexes is described. The method is practical and convenient both for determining molecular weight distributions and for preparing gelatin fractions. It is shown that fractions of equal reduced viscosity, and hence molecular weight, derived from gelatins of similar isoelectric points may still differ in important respects, thus confirming the conclusions of Pouradier and Venet, who prepared fractions by a different method of fractionation. It is established that the rigidity of gels formed from the gelatin fractions is independent of molecular weight, at least at 5.5 g./100 ml. concentration. There is some indication that, for the lowest molecular weight fraction, a slight variation of rigidity with molecular weight is occurring. Some other structural feature, at present unidentified, must be associated with the mechanism of gel formation.

The composition and structure of gelatin are related to the method of manufacture, and to the physical properties of gelatin solutions and gels. The importance of the isoionic point, molecular weight distribution and a gel-forming factor are discussed in connexion with the experimental results.

AbstractA method is described for measuring the separate properties, colour and clarity, of gelatin and glue solutions. The optical densities of gelatin or glue solutions, before and after filtration by means of a bacterial filter, are measured either as a function of wavelength, with a spectrophotometer, or in terms of the light transmitted by standard colour filters, with a photoelectric absorptiometer. The limitations of the method and its usefulness in routine control are discussed.

A proportional counter, filled with hydrogen or methane, has been developed for the measurement of monoenergetic neutron fluxes in the energy range 0.1 to 1.0 Mev. The pulse distributions obtained from the recoil protons are in good agreement with the calculated distributions allowing for end and wall effects over this energy range for appropriate fillings. Flux measurements can be made with certainty to better than 5 percent. Calculations of wall and end effects have been repeated using the latest range energy relation for protons.

An extrusion method for the measurement of the flow properties of unseasoned linoleum is described. The method is suitable either for the study of absolute flow properties, or for routine testing, of unseasoned linoleum, and examples of its application are given. The significance of the method in relation to the manufacture of linoleum is discussed, particularly in relation to the effects of combined hydrostatic pressure and shearing stress as in the calendering process.

A constant stress extension apparatus designed to measure extension-time curves for plastics for which Poisson's ratio may be taken as 0.5 is described. Extension up to 50% can be measured, and the provision of low- and high-magnification optical lever systems for measurement of the extension enables small and large movements to be measured. The constant stress is obtained by means of a cam, the shape of which has been computed. Some preliminary results are given of the behaviour of a nitrocellulose plastic, in order to illustrate the use of the instrument. This material does not obey the `Boltzmann Superposition Principle' for large stresses.

AbstractAbsolute measurements of the Theological properties of caulking compounds designed for use with hand or air pressure guns are described. The methods used arc the tube plastometer, for extension measurements, and the divided cylinder plastometer, which can be used for measurements at stresses both above and below the yield value for continuous flow. Below this yield value irreversible deformation occurs, but the rate of shear decreases continuously as shear proceeds. Above the yield value the behaviour approximates to that of a Bingham plastic body complicated, in some instances, by thixotropy. The results obtained have been applied to the practical problems of filling and the use of hand pressure guns. The temperature dependence of flow properties has also been studied.

The general behaviour of stiff pastes is discussed in order to select the most suitable form of apparatus for rheological measurements. Two new instruments, each of the concentric cylinder type, which can be applied to different types of stiff paste, are described. The first relies on the use of a narrow annulus to enable absolute calculations to be made, and incorporates a novel method of filling by using a split outer cylinder. It cannot be used satisfactorily with systems showing very rapid shear hardening, for which the second instrument was designed. This instrument enables the shear to be determined at all points across a wide annulus. Measurements show that, for some systems, Bingham's law of plastic flow is obeyed for each value of the shear, the effect of the shear hardening being to give an increasing value to the yield stress, as the amount of shear increases. Two new ideal rheological bodies are suggested and the effect of hydrostatic pressure on the flow properties of materials is discussed.