Showing papers by "Ministry of Supply published in 1953"
184 citations
176 citations
TL;DR: PHOSPHATE esters separated on paper chromatograms are usually detected by degrading them on the paper with acid to give ortho-phosphoric acid and detecting this by the reaction with molybdate and a reducing reagent.
Abstract: PHOSPHATE esters separated on paper chromatograms are usually detected by degrading them on the paper with acid to give ortho-phosphoric acid and detecting this by the reaction with molybdate and a reducing reagent. The procedure of Hanes and Isherwood1 is based upon this and is widely used. This technique suffers from two disadvantages. In the first place, the prolonged initial ‘digestion’ necessary to break down the more resistant esters frequently leaves the paper in a very fragile state; and secondly, further analyses cannot be carried out on the spot after treatment. In order to avoid these disadvantages the following technique was developed. It depends upon the fixation of ferric ions by the esters and the reaction of the free ferric ion with salicylsulphonic acid. If the paper is not strongly buffered it is sprayed with 0.1 per cent FeCl3.6H2O in 80 per cent alcohol, dried in air at room temperature and then sprayed with 1 per cent salicylsulphonic acid in 80 per cent alcohol. Upon drying, the phosphates appear as white spots on a pale mauve background, ortho-phosphate having a band of deeper mauve surrounding it. The colour formation occurs only when the pH of the residual moisture in the paper is about 1.5–2.5. This can be checked conveniently with thymol blue, since the colour formation occurs most satisfactorily when the paper just turns this indicator red. Further indications of unsatisfactory pH are that below this range no colour is formed, whereas above the range the colour is orange-yellow and definition of the spots is very poor.
166 citations
146 citations
TL;DR: The distribution of inhaled bacterial aerosols has been studied in guinea-pigs, monkeys and mice, using Bacillus subtilis spores labelled with radiophosphorus, and the subsequent fate of the retained particles accords with what is known about ciliary removal.
Abstract: The distribution of inhaled bacterial aerosols has been studied in guinea-pigs, monkeys and mice, using Bacillus subtilis spores labelled with radiophosphorus. Particle sizes from about 1 to 12μ have been used.The guinea-pig shows the expected change of distribution with particle size; the proportion retained in the head increases with increased particle size. The figures correspond closely with those for man. Monkeys show similar results but are more irregular.The subsequent fate of the retained particles has been studied and accords with what is known about ciliary removal.The work is intended to link with parallel investigations of respiratory infection in closely similar conditions, and its implications are discussed in a paper on that subject (Druett et al. 1953).
87 citations
TL;DR: The hypothesis advanced earlier to account for the toxicity of fluoroacetate (FCH2.COONa) has been proved recently by the isolation of an enzymically synthesized mono-fluorotricarboxylic acid in crystalline form1, prepared from the products of interaction of kidney tissue with fumarate and fluoro acetate.
Abstract: THE hypothesis advanced earlier to account for the toxicity of fluoroacetate (FCH2.COONa) has been proved recently by the isolation of an enzymically synthesized mono-fluorotricarboxylic acid in crystalline form1, prepared from the products of interaction of kidney tissue with fumarate and fluoroacetate. Though there was much to suggest that it was mono-fluorocitric acid, this had not been rigorously proved by a comparison of the infra-red spectrum with a synthetic specimen. The recent synthesis by one of us (D. E. A. R., in the press) of fluorocitric acid has made it possible to compare the infra-red spectra of the barium salts of this with the barium salt from 1.5 mgm. of the enzymically synthesized (natural) crystalline compound isolated in Oxford (by R. A. P. and R. W. W.).
43 citations
TL;DR: In this article, the wave functions at the boundaries between the cells are described, based either on least square fitting or on expansion of ψ in terms of functions which are orthogonal over the boundaries.
Abstract: The cellular method has been applied to the determination of electronic wave functions of the Bloch type in PbS. In each cell ψ is expanded in terms of ‘Kubic harmonics9, and a table of these functions (for a NaCl type of lattice) for prominent points in momentum space is included. An attempt has been made to establish a self-consistent field, by treating only the electrons with k = 0, but results have shown that this approximation is not very good. Methods of matching the wave functions at the boundaries between the cells are described, based either on least square fitting or on expansion of ψ in terms of functions which are orthogonal over the boundaries. These methods have been tested with the empty lattice test. Curves are given showing the approximate band structure in two prominent crystallographic directions. The resulting width of the full band is about 6 eV, that of the conduction band about 7 eV. The forbidden energy gap is very small ( -4 eV /degree, about half the experimental value.
35 citations
01 Oct 1953
TL;DR: In this paper, the phase changes which occur on total reflection are modified when a metal plate is placed near and parallel to a totally reflecting boundary, and the phase difference between plane waves of equal amplitude, polarized in and perpendicular to the plane of incidence, can be varied from -π through zero and up to the value obtained without the plate.
Abstract: The phase changes which occur on total reflection are modified when a metal plate is placed near and parallel to a totally reflecting boundary. In particular the phase difference between plane waves of equal amplitude, polarized in and perpendicular to the plane of incidence, can be varied from -π through zero and up to the value obtained without the plate. When the refractive index is greater than or equal to 1 + 21/2, there are two positions of the plate for which the reflected wave is circularly polarized, and in which the electric vector rotates in opposite directions. Measurements of this effect have been made at a wavelength of 1.25 cm, with a microwave analogue of the optical spectrometer, and a 45° Perspex prism with faces 6 in. square. In view of the limitations due to diffraction the results are in good agreement with the theory, and are an elegant way of showing the presence of the evanescent wave beyond a totally reflecting boundary.
23 citations
TL;DR: Spores are formed when vegetative cells of sporing aerobes are shaken with distilled water at 37° and these spores are derived from the small number of cells which survive lysis.
Abstract: Spores are formed when vegetative cells of sporing aerobes are shaken with distilled water at 37°. These spores are derived from the small number of cells which survive lysis. The sporulation process involves increase and concentration of solid material in the cell, and is achieved at the expense of the products of lysis of 80 to 90 per cent of the resuspended cells.
23 citations
16 citations
TL;DR: In this paper, the conditions for polarography were laid down and the theoretical aspects of the results obtained with a single-sweep cathode ray polarograph are discussed, and the mutual interference of the elements is detailed and recommendations for their determination in the presence of one another.
TL;DR: In this paper, the results obtained by the use of a single-sweep cathode ray polarograph are given and suggestions regarding the fundamental nature of some electrode reactions are made.
TL;DR: A spectrophotomctric study of the reaction between haematoxylm and aluminium to form a complex was performed in this article, where it was concluded that the complex is formed not with haem atoxylin but with haeniatein which is formed from.
TL;DR: In this article, the effect of electric charges on the particles of an aerosol on its rate of coagulation due to Brownian movement, differences in gravitational settling and turbulence was investigated.
Abstract: Smoke-chamber experiments have been carried out to determine the electric charge distributions and the constants descriptive of coagulation and surface loss of aerosols of porous silica powder, magnesium oxide and ammonium chloride. The data obtained were used to test the hypothesis that the rate of coagulation is affected by the electric charge distribution. Calculations have been made of the effect of electric charges on the particles of an aerosol on its rate of coagulation due to Brownian movement, differences in gravitational settling and turbulence. A simple expression for the coagulation constant was obtained which was found to be a function of the fraction of positive particles, the fraction of negative particles, the average particle charge of each sign and the average radius. A more exact treatment of ageing data than has previously been presented indicated a possible variation in the coagulation and surface loss constants with time, and this variation has been shown to be related to changes in the electric charge distribution.
TL;DR: In this paper, a method for the spectrophotometric determination of fluoride is described, which can detect down to 0.05 p.p.m. of fluoride on a 10 gram sample with precision of rather better than ± 10% with larger amounts of fluoride.
TL;DR: In this article, the conditions for polarography were laid down and the theoretical aspects of the results obtained with a single-sweep cathode ray polarograph were discussed, and recommendations for their determination in the presence of one another were presented.
TL;DR: In this paper, a nonrelativistic approximation to Dirac's new variational formulation of the single-stream electrodynamic field equations is presented using 3-vector notation and m.k.s. units throughout.
Abstract: Summary A non-relativistic approximation to Dirac's new variational formulation of the single-stream electrodynamic field equations is presented using 3-vector notation and m.k.s. units throughout. The Hamilton-Jacobi theory of a rotational space charge stream is developed. The variational formulation is generalized to the multi-stream case—both for a finite number and a non-denumerably infinite number of streams.
TL;DR: It is confirmed that the presence of iron as impurity in titanous chloride and sulphate solutions invalidates the use of potassium dichromate as a standard substance.
TL;DR: The application of the aluminium-haematoxylin reagent to the determination of fluoride in sea-water, river and potable waters, and sewage effluent is described in this article.
TL;DR: The advantages of microwave aerial systems using lenses over those using reflectors are briefly touched upon, various criteria are stated by which the usefulness of a lens aerial may be judged, and a brief study is made of the various types of microwave lens currently in use or projected.
Abstract: The advantages of microwave aerial systems using lenses over those using reflectors are briefly touched upon, various criteria are stated by which the usefulness of a lens aerial may be judged, and a brief study is made, at an introductory level, of the various types of microwave lens currently in use or projected.
TL;DR: The rate-controlling process is thus the transfer of the heat necessary for the evaporation of the drop1 as discussed by the authors, which occurs in the vapour phase during combustion of liquid fuel drops.
Abstract: DURING the combustion of liquid fuel drops, the chemical oxidation occurs in the vapour phase. The rate-controlling process is thus the transfer of the heat necessary for the evaporation of the drop1.
TL;DR: In this paper, Torrey1 has discussed the possibilities of using a relatively rapid approach to resonant conditions as a method of searching for unknown nuclear resonances, and has described methods in which Hcffff1 (the radio-frequency field) has been pulsed.
Abstract: TORREY1 has discussed the possibilities of using a relatively rapid approach to resonant conditions as a method of searching for unknown nuclear resonances, and has described methods in which H
1 (the radio-frequency field) has been pulsed. Where the establishment of resonance conditions is rapid compared with the spin-lattice relaxation time, this method gives theoretically a larger nuclear signal than that available in cases where the resonance is excited continuously or frequently. We have found that a method whereby H
1 is fixed and H
0 (the D.c. magnetic field) is rapidly swept over a relatively wide range provides not only a simple method of demonstrating nuclear resonance effects, but also one that has possibilities in rapid searching for unknown resonances.
TL;DR: It is unrealistic to examine the vertical in navigation only in terms of providing a reference for sextant altitude measurement and the paper will therefore discuss more general problems of aircraft stability, which can themselves be studied by means of the sextants.
Abstract: This paper will discuss various methods of defining the vertical in aircraft. It is unrealistic to examine the vertical in navigation only in terms of providing a reference for sextant altitude measurement and the paper will therefore discuss more general problems of aircraft stability, which can themselves to some extent be studied by means of the sextant.
01 Jun 1953
TL;DR: In this article, a general summary of the problem of interpreting interchangeability and a limit of size; the general nature of a fit and the limits of size which determine it are briefly examined.
Abstract: This paper begins with a general summary of the problem of interpreting interchangeability and a limit of size; the general nature of a fit and of the limits of size which determine it are briefly examined. Some statistical problems of assembly and inspection and their effects on interchangeability and on the practical interpretation of a limit of size are investigated. The standard of measurement is considered in some detail as defining gauge tolerances and errors of measurement, and as giving guidance in relation to certain varying degrees of interchangeability that have been shown to exist. The effect of these arguments on the standard of limits and fits is discussed and certain practical pitfalls in the statistical arguments are briefly examined. Low degrees of interchangeability are discussed and also interchangeability in relation to complex forms, position, and angular dimension. It is shown how the various degrees of interchangeability can be indicated by means of suitable provisions in the standa...
TL;DR: An investigation into the methods of construction of radiation thermocouples using semiconducting thermoelectric materials is described in this paper, based on the description given in patent applications by E. Schwarz.
Abstract: An investigation into the methods of construction of radiation thermocouples using semiconducting thermoelectric materials is described. This work has been based on the description given in patent applications by E. Schwarz. Performance data for these thermocouples is included together with that obtained for certain commercial couples made by Schwarz and measured by the authors.