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.

Characteristics of Some Non-Screen Films used in Industrial Radiology

Abstract: In the past, difficulties have often arisen in practice due to the lack of flexibility in control of both contrast and speed of X-ray films. In an endeavour to overcome these limitations considerable success was obtained by varying the development time within the range of 2-20 min., and this led to a need for fuller and more systematized information on the characteristics of the generally used X-ray films. An investigation has, therefore, been made of the characteristics of selected X-ray films suitable for use with metal intensifying screens, with particular reference to their variation with time of development. The results show that a much wider range of film speed and contrast can be obtained. In extreme cases speed ratios of 400: 1, and contrast ratios of 5: 1 are obtainable by modification of the time of development alone. Applications of this technique to practical radiography are considered both for obtaining maximum contrast and also, a more difficult problem, for matching the density range of the film to the range of thickness in the specimen under examination. The variation of development technique as an alternative to variation of tube voltage is discussed and it is pointed out that the former is more useful for voltages above 200 kV., whereas the latter is of more importance at lower voltages. It is hoped to prepare a further paper on this latter aspect.

Recent advances in potted and printed circuits

Abstract: The various potting resins are described in relation to the variation of properties with different proportions of hardener and the effects on the parameters of the potted components. The causes of failure of potted circuits are discussed. Design problems in the use of printed circuits are examined with particular reference to questions of conductor thickness and spacing. A method of sealing printed circuits by a thin polysulphide rubber layer which is sprayed or brushed on is described.