Showing papers by "Ministry of Supply published in 1954"

The Molar Heats of Lead Sulphide, Selenide and Telluride in the Temperature Range 20°K to 260°K

Abstract: An apparatus suitable for calorimetry at low temperatures is described. With it, the molar heats of lead sulphide, selenide and telluride have been measured between 20°K and 260°K. These salts show a normal family of molar heat curves, from which the usual thermodynamic functions have been calculated. An analysis of corrections required with the method of calorimetry used, is given in an Appendix.

A relationship between body fat and plasma pseudo-cholinesterase.

Abstract: The aim of this study was to determine whether there was any relationship between body fat and pseudo(or plasma) cholinesterase. Hutchinson, McCance & Widdowson (I~sI), in reporting their studies of undernutrition and feeding, pointed out that, at the end of rehabilitation when men became ‘fat’, the average pseudo-cholinesterase was higher than normal. It therefore seemed of interest to investigate the relationship of body fat to pseudo-cholinesterase in men in metabolic equilibrium as opposed to that in men at the end of a dynamic process of equilibrium.

The analysis of adenosine triphosphate and adenosine diphosphate preparations by paper ionophoresis.

Abstract: The importance of adenosine triphosphate (ATP) in cell metabolism and the instability of its preparations during storage have resulted in a keen interest being shown in methods for its analysis. Until recently the most satisfactory analysis of ATP has involved the preparation and use of highly purified enzyme systems (Bailey, 1949). Other less time-consuming methods involving paper chromatography are now available. The most recent (Eggleston & Hems, 1952) involves the separation and estimation of ATP, adenosine 5-phosphate (AMP),orthophosphateandpyrophosphate + adeno. sine diphosphate (ADP) by 'two-solvent onedimensional chromatography' and the individual determination of pyrophosphate by a further chromatographic separation. During the development of a general scheme for the analysis of acid-soluble phosphates a method involving paper ionophoresis was evolved which was found to separate all the above esters in one operation and in the space of a few hours. The technique which is described below has been applied to the analysis. of seven samples of ATP and one of ADP.

Polarization of Radar Echoes from Meteorological Precipitation

Abstract: MEASUREMENTS on the polarization of radio waves reflected from meteorological precipitation are sometimes handicapped by limitations of the investigating radar, and this is particularly so in the case of so-called circularly polarized radars. In practice, all radars radiate an elliptically polarized wave, and it can be shown that a perfectly spherical target will appear to produce two orthogonally polarized circular components differing in magnitude by 40 dB. if the voltage ellipticity ratio of the radiated wave is 0.99, and by 20 dB. if the ellipticity ratio is 0.9. This sets a limit to the accuracy obtainable in field measurements.

Infra-red Spectra of Fluorinated Hydrocarbons

Abstract: WE have recently examined for analytical purposes the infra-red spectra of some fully fluorinated hydrocarbons. Complex interactions occur in compounds of this type, and it is not to be expected that the absorption frequencies of any particular structural group will be constant: but nevertheless some regularities have been observed which may be useful.

Intensities of Discrete Radio Sources in Cygnus and Cassiopeia at 22.6 Mc.s.

Abstract: IT is important both for the understanding of the nature of the localized radio sources and the determination of interstellar radio absorption to extend the measurement of the spectra of the sources to as low radio-frequencies as possible. Ionospheric transmission sets a limit, but by choosing frequencies not too close to the critical frequency, and restricting observations to days of low ionospheric disturbance, reasonably accurate measurements may be obtained. In this way, we have recently made measurements at a frequency of 22.6 Mc./s. (λ = 13.3.m.) by means of an interferometer consisting of two aerials spaced in the east–west direction at 20 wave-lengths apart, thus producing lobes in the aerial pattern at intervals of about 3°. Each aerial consists of an array of six full-wave dipoles giving a vertically directed beam of width ± 22° and ± 9° in the north–south and east–west directions respectively. The recording apparatus is a simplified form of the type described by Machin, Ryle and Vonberg1, whereby the receiver is continually switched to a standard noise diode source which is automatically adjusted by a servo-mechanism to equalize the received radiation.

The comparison and calibration of power-measuring equipment at wavelengths of 3 cm and 10 cm

Abstract: A description is given of recent experiments which have resulted in the production of substandard power-measuring equipment for wavelengths in the 3cm and 10cm wavebands. The equipment consists of two calibrated thermistor bridges measuring up to 1 mW of microwave power, and these may be regarded as the present United Kingdom substandards. The accuracy of the final calibration carried out at wavelengths of 3.18 and 10.77cm is estimated at ±2% and ±1% respectively. Good agreement was obtained in a comparison of the two standards used in the 3cm calibration, the water calorimeter and the torqueoperated vane wattmeter developed by Cullen and Stephenson.

Solar Radio Asymmetry at 4-Metres Wave-length

Abstract: IN 1948, Hey, Parsons and Phillips1 reported that at 4.1-metres wave-length bursts of radio emission, usually of a few minutes duration, occurred more often in association with flares on the eastern half of the sun's disk than on the western half. Subsequent observations have confirmed this conclusion. In a recent analysis of radio emissions at 1.5-metres wavelength, Dodson, Hedeman and Owren2 could find no evidence of this asymmetry. The following reasons may explain why they failed to observe the effect.

The Use of Oxygen Apparatus by Acclimatized Men

Abstract: Although oxygen breathing apparatus has a wide range of applications it is only in Himalayan mountaineering that the users are likely to be fully acclimatized to high altitude. Above 25000 ft. even acclimatized men are severely handicapped without additional oxygen and hence we have little accurate information on phenomena occurring at these heights. The following notes describe observations made during the British Expedition to Cho Oyu of 1952 and the Everest Expedition of 1953, when oxygen apparatus was used to a greater extent than in previous mountaineering. The conditions met in mountaineering at great altitudes are not easy, and a breathing set must meet several stringent requirements. Thus the greatest weight which a climber can carry over difficult ground for many hours is about 60 lb., but a load as great as this is a severe handicap and weight and bulk should both be small.

Production of Individual, Sized, Droplets by High-Voltage ‘Firing’ from a Micropipette

Abstract: THERE are several satisfactory methods for the continuous production of uniform droplets. The range below 10 microns may be covered in the La Mer vapour condensation apparatus, 10 µ–1,000µ, by the spinning disk principle, 100 µ to several millimetres by the vibrating tip, interrupted jet and micro-burette principles and 800 µ to 6–7 mm. by liquid falling by gravity from the tip of a vertical tube.

The Impact of Development and Research on Production and Design

Abstract: The paper deals with some technical activities which are of particular importance in relation to production, but which are not always recognized as having a direct bearing thereon. Simplification of product, functional development and production research provide means by which existing facilities may be made to yield greater output, that is, to increase production efficiency. They also make it certain that industry will in the future employ those processes which ensure the maximum economic gain.The attitude of the mechanical engineer to production techniques as a part of design also receives consideration, together with the desirability of infusing designers and draughtsmen with a greater interest in new methods. The responsibility of industry in affording training for this purpose is also discussed.The lack of adequate support for production research is emphasized, while attention is drawn to the difficulties of small firms in benefiting from the results of research and development work on new processes.