The metallography of solid mercury and amalgams

During the last three years an investigation into the properties of dental alloys and the phenomenon of setting of amalgams has been in progress in the Metallurgy Department of the National Physical Laboratory on behalf of the Dental Investigation Committee of the Department of Scientific and Industrial Research, and with the aid of funds provided by the Dental Board of the United Kingdom. This investigation has been concerned chiefly with a study of the ternary amalgams of silver, tin and mercury, which are the basis of amalgams used as filling materials in dental practice. Owing to the absence of any recorded systematic survey, it became necessary to examine the constitution of the amalgams over the whole range of composition from 0 to 100 per cent, mercury. For this purpose it was desired to determine the microstructure of pure mercury and the dilute amalgams, in addition to those which, containing smaller percentages of mercury, are completely solid at ordinary temperatures. The melting point of pure mercury is — 38 • 85° C. In all series of amalgams, that is, alloys of mercury with other metals, therefore, the alloys within certain ranges of composition are completely or partially molten at normal temperatures. As a consequence, the investigation of the constitution in the solid state of the whole of an alloy system in which one of the components is mercury requires the application of a technique developed with particular reference to the characteristic properties of this metal.

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Radiotherapy reference dose audit in the United Kingdom by the National Physical Laboratory: 20 years of consistency and improvements

Physics and Imaging in Radiation Oncology ◽

10.1016/j.phro.2017.07.005 ◽

2017 ◽

Vol 3 ◽

pp. 21-27 ◽

Cited By ~ 9

Author(s):

Russell A.S. Thomas ◽

Matthew A. Bolt ◽

Graham Bass ◽

Rebecca Nutbrown ◽

Tao Chen ◽

...

Keyword(s):

United Kingdom ◽

National Physical Laboratory ◽

Reference Dose ◽

The United Kingdom ◽

Physical Laboratory

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The optical determination of high metallurgical temperatures - The melting point of iron

Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character ◽

10.1098/rspa.1930.0145 ◽

1930 ◽

Vol 129 (809) ◽

pp. 91-114

Keyword(s):

Melting Point ◽

Molten Metal ◽

National Physical Laboratory ◽

Optical Pyrometer ◽

Chemical Attack ◽

Physical Laboratory ◽

Thermal Changes ◽

Refractory Crucible ◽

Optical Determination

The present investigation has been carried out in the Metallurgical Department of the National Physical Laboratory in order to adapt the optical pyrometer to the estimation of the fusion temperatures of materials of high purity and high melting point and of substances of corrosive or volatile nature. Melting points and thermal changes in the solid state at high temperatures are generally determined by means of platinum thermocouples which are protected from the molten metal or its vapour by insertion in a refractory sheath. Contamination of the molten metal is frequently occasioned by chemical attack which takes place between the metal and the refractory crucible or couple sheath. This is particularly marked when the refractories contain siliceous material.

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Mathematics and Aeronautics

Journal of the Royal Aeronautical Society ◽

10.1017/s0368393100073089 ◽

1960 ◽

Vol 64 (595) ◽

pp. 375-394 ◽

Cited By ~ 10

Author(s):

M. J. Lighthill

Keyword(s):

United States ◽

North Carolina ◽

United Kingdom ◽

Applied Mathematics ◽

The United States ◽

National Physical Laboratory ◽

Memorial Lecture ◽

The United Kingdom ◽

Physical Laboratory ◽

Wilbur Wright

The 48th Wilbur Wright Memorial Lecture, “Mathematics and Aeronautics” was given by Mr. M. J. Lighthill, F.R.S., before a large and distinguished audience at the Institution of Mechanical Engineers, 1 Birdcage Walk, on 19th May 1960. Dr. E. S. Moult, C.B.E., B.Sc, F.R.Ae.S., M.I.Mech.E., President of the Society, presided.As has become the custom, before the lecture was delivered the President presented the awards made by the Council for 1960 for outstanding contributions to aeronautics. In the unavoidable absence of the Secretary he was assisted by Miss E. C. Pike, M.A., A.F.R.Ae.S., Secretary of the Medals and Awards Committee and Editor of The Aeronautical Quarterly. The list of the awards presented on this occasion was published in the June 1960 Journal—(p. XXXII).The President, introducing the lecturer, reminded the audience that the Wilbur Wright Lecture commemorated the first manned, powered controlled flight by Wilbur Wright at Kitty Hawk, North Carolina on 17th December 1903. The first Wilbur Wright Memorial Lecture was held in 1913 and they had been held each year ever since, through two World Wars; in itself a wonderful record. The custom had been, and would continue to be, to have alternately a lecturer from the United Kingdom and a lecturer from the United States; last year the lecture had been by Mr. McCarthy of Chance Vought and next year again it would be by an American.The Wilbur Wright Lectures had been a most distinguished series by distinguished lecturers, and he was sure that the lecture that night would be in keeping. His pleasant duty was to introduce Professor Lighthill—or as they had to call him Mr. Lighthill now that he was Director of the Royal Aircraft Establishment, which was an even greater distinction. Mr. Lighthill was the youngest Director that the R.A.E. had ever had—that alone was a tribute to Mr. Lighthill's ability and his high standing in the profession. Before joining the Royal Aircraft Establishment Mr. Lighthill was Professor of Applied Mathematics at Manchester University, and for a time, after leaving Cambridge, had worked at the National Physical Laboratory where he applied the mathematics of Cambridge to the problems of aerodynamics. His lecture was on “Mathematics and Aeronautics” he would ask Mr. Lighthill to deliver the 48th Wilbur Wright Memorial Lecture.

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Iron of high purity

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1935.0230 ◽

1935 ◽

Vol 153 (878) ◽

pp. 172-200 ◽

Cited By ~ 6

Keyword(s):

High Purity ◽

National Physical Laboratory ◽

The Past ◽

Oxygen System ◽

Physical Laboratory ◽

Metallurgy Department ◽

Purity Iron ◽

High Purity Iron ◽

Commercial Iron ◽

Made In

During the past eleven years (1925-35) several equilibrium diagrams involving iron as one of the components have been investigated at the National Physical Laboratory. The provision of the numerous alloys required for these researches has necessitated the production of quantities of high purity iron. Tritton and Hanson, when they began work on the iron-oxygen system at the National physical Laboratory, considered that the best commercial iron then obtainable was unsuitable for their work, and in the period 1922-24 prepared iron electronically according to the method of Cain, Schram, and Cleaves. At first the present authors produced iron in a somewhat similar manner, but when improvements in analytical methods revealed impurities in samples originally considered satisfactory, alterations were made in the method of preparation. Comprehensive analyses indicate that the latent batch of iron prepared the authors is very low in impurities, yet the physical properties of this material suggest that some disturbing factor may still be present. The problem is apparently complex and a rapid solution appears unlikely In these circumstances it was thought that the present publication of data concerning several batches of iron prepared at the National Physical Laboratory would serve a useful purpose. In addition to information obtained by the authors, particulars of a batch of iron prepared by Mr. W. E. Prytherch, M. Sc., also of the Metallurgy Department, N. P. L., are included, together with occasional results obtained by older members of tde staff. The results of Tritton and Hanson ( loc. cit .) are omitted, how-ever, as these have already been published.

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Safety in the Dover Strait: a Progress Report

Journal of Navigation ◽

10.1017/s0373463300025170 ◽

1974 ◽

Vol 27 (1) ◽

pp. 51-65

Author(s):

P. J. Gregory

Keyword(s):

Traffic Engineering ◽

National Physical Laboratory ◽

Civil Aviation ◽

The United Kingdom ◽

Steering Group ◽

Marine Traffic ◽

Physical Laboratory ◽

Royal Institution ◽

Traffic Systems ◽

Set Up

AS readers of the Journal will know the Department of Trade and Industry set up in 1971 a Marine Traffic Systems Steering Group, to commission and coordinate research and development relating to the problems of marine traffic behaviour and to consider practical measures which could be undertaken as regards the Dover Strait area. The Group comprises mariners, economists, scientists and administrators from the Department of Trade and Industry including the National Physical Laboratory, representatives of the Civil Aviation Authority, the Ministry of Defence and, more recently, the Chamber of Shipping of the United Kingdom and Trinity House. Hargreaves has recently described briefly some of the earlier work arising out of the Group's existence. This paper describes in more detail the activities of the Steering Group from the time of its first meeting in March 1971 to the present day (October 1973). Many of the results of this activity are already known to Members of the Institute as a result of the publication in the Journal of papers read at the Conference on Marine Traffic Engineering held at the N.P.L. in May 1972 and sponsored jointly by the Royal Institute of Navigation and the Royal Institution of Naval Architects.

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Accuracy and Linearity of Spectrophotometers in Clinical Chemistry Laboratories

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/000456328001700205 ◽

1980 ◽

Vol 17 (2) ◽

pp. 87-90 ◽

Cited By ~ 5

Author(s):

John F Stevens

Keyword(s):

Quality Control ◽

United Kingdom ◽

Clinical Chemistry ◽

National Physical Laboratory ◽

Cobalt Nitrate ◽

The United Kingdom ◽

Physical Laboratory ◽

Wide Scatter ◽

Chemistry Laboratories ◽

Set Up

Solutions of cobalt nitrate sealed in vials were circulated to all clinical chemistry laboratories in the United Kingdom. Participants reported wavelengths of maximum absorbance together with the actual absorbances obtained. The results were compared with values obtained from the National Physical Laboratory. The results show a wide scatter, and several instruments were extensively repaired or replaced as a result of the survey. The most recently marketed machines had the best performance, and it is suggested that regular quality control and maintenance of the machines is vital. It is intended to set up a scheme for regular monitoring of spectrophotometer performance.

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