Ministry of Supply

About: Ministry of Supply is a based out in . It is known for research contribution in the topics: Polarography & Bacillus (shape). The organization has 416 authors who have published 355 publications receiving 8951 citations. The organization is also known as: MoS.

On the Energy-Spectrum of an Almost Periodic Succession of Pulses

Abstract: An analysis is presented of the effect of (i) irregularities in the amplitude of pulses, and (ii) jitter in the repetition rate on the energy-spectrum of a succession of pulses. In both cases the spectrum bas two components: (a) a line spectrum, and (b) a continuous spectrum. In case (i), the envelope of both spectra is proportional to the envelope of the energy-spectrum of a single pulse and the lines in the line spectrum are spaced by the repetition frequency (see Figs. 1 and 2). In case (ii), the envelopes of the spectra are not the same as the envelope of a single pulse, and the lines are spaced by the mean repetition frequency (see Figs. 3 and 4).

Cross-polarization of the Radar Melting-Band

Abstract: WHEN plane-polarized radiation is scattered by meteorological precipitation particles other than spheres, a component of the back-scattered energy is polarized at right-angles to the plane of polarization of the incident wave. This component will be referred to as the ‘cross-polarized’ component in this communication. Recent observations at Cambridge and Malvern have shown that the melting particles found just below the freezing-level, which give rise to the well-known radar ‘melting-band’1, produce back-scattered radiation with a greater cross-polarized component than that given by the rain below and the snow above the freezing-level. These observations have been made using separate aerials for transmission and reception, by comparing the echo received when the aerials have their planes of polarization parallel with that received when the plane of polarization for reception is at right-angles to that for transmission.

The detection and measurement of water droplets

Abstract: The use of a dyestuff (Naphthol Green B) in gelatine, coated on the slides of a cascade impactor, provides a method for determining the drop-size distribution of fogs and water sprays which is easy to apply in practice and gives a permanent record for subsequent microscopic analysis. Calibration of the stain remaining after evaporation of a droplet impacting on the slide shows it to be, on the average, 2.5 times the diameter of the droplet. The method can be readily used for droplets of less than 1 μ diameter.

A systematic assessment of dissolved oxygen supply in a 20-litre culture vessel

Abstract: The factors influencing aeration are discussed and, using the sulphite oxidation method of measurement, the influence of impeller diameter and speed, air rate, and air pressure on the aeration efficiency of a 20-litre culture vessel has been determined and the power consumed by the impeller measured. Conditions are given for obtaining sulphite oxidation rates of 200–250 millimoles of O2 per litre of medium per hour which can be increased to 500–600 millimoles by raising the operating gauge pressure from zero to 1·36 atm.

Some observations of air flow over the sea

Abstract: Wind speeds were measured over the sea at five heights up to 8 m. Though the fetch was limited, the wind profiles obtained are considered representative of flow over the sea. The wind speed varies logarithmically with height when the temperature gradient is small. Assuming that laboratory laws of flow are applicable, values of the roughness parameter z0 are deduced. It is found that z0 increases from about 0·02 cm in a wind of 5 m/sec to 0·25 cm at 9 m/sec. The relationship between wind speed and z0 however is not unique for the state of the surface is determined by other factors beside wind speed. In inversion conditions the wind-speed distribution departs from the logarithmic form a few metres above the surface. The results obtained are compared with those of some other workers. Bi-directional vanes were used to obtain gustiness measurements at the site. While the vertical gustiness is found to be of similar magnitude to that over land surfaces of comparable roughness, the cross-wind gustiness appears to be greater over the sea.