scholarly journals The National Physical Laboratory

Nature ◽  
1933 ◽  
Vol 132 (3322) ◽  
pp. 23-23 ◽  
Keyword(s):  
National Physical Laboratory ◽  
Physical Laboratory

scholarly journals 75th Foundation Day of CSIR-National Physical Laboratory: Celebration of Achievements in Metrology for National Growth

MAPAN ◽  
2021 ◽  
Author(s):  
Sanjay Yadav ◽  
Goutam Mandal ◽  
V. K. Jaiswal ◽  
D. D. Shivagan ◽  
D. K. Aswal
Keyword(s):  
National Physical Laboratory ◽  
Physical Laboratory ◽  
National Growth

Comparison of the acceleration due to gravity at the National Physical Laboratory, Teddington, the Bureau International des Poids et Mesures, Sèvres, the Physikalisch-Technische Bundesanstalt, Brunswick, and the Geodetic Institute, Potsdam

1952 ◽  
Vol 213 (1114) ◽  
pp. 408-424 ◽  
Keyword(s):  
National Physical Laboratory ◽  
Absolute Value ◽  
Geodetic Institute ◽  
Physical Laboratory ◽  
The Absolute

The values of gravity at these stations have been compared by means of pendulum observations with Invar invariable pendulums. The observed differences of gravity from the National Physical Laboratory are: B. I. P. M. -256·73 ± 0·49 mgal P. T. B. + 68·68 ± 0·49 mgal Bad Harzburg - 15·68 ± 0·49 mgal The accuracy of the measurements is not so great as has been achieved once or twice previously with the same apparatus, mainly because the changes in the lengths of the pendulums were greater than usual. These differences have been combined with German pendulum observations and with gravimeter comparisons with the following results: Value of gravity at N. P. L. on the Potsdam system: 981196·29 ± 0·3 mgal. Differences between sites of absolute determinations of gravity: N. P. L. - B. I. P. M. +256·45 ± 0·3 mgal N. P. L. - P. T. B. - 68·98 ± 0·3 mgal P. T. B. - Potsdam - 8·95 ± 0·4 mgal ( g at Potsdam = 981274 mgal.) The effects of these results on gravity surveys based on Cambridge and on the absolute value of gravity are indicated.

scholarly journals A standard measuring machine

1912 ◽  
Vol 87 (597) ◽  
pp. 385-390
Keyword(s):  
National Physical Laboratory ◽  
Standard Measuring ◽  
Physical Laboratory ◽  
Accurate Comparison ◽  
Measuring Machine ◽  
Regular Work ◽  
Absolute Measurements ◽  
Line Standard

In some physical researches it is required to measure the dimensions of a regular solid, whether parallel-sided, cylindrical, or spherical-ended, with the greatest possible accuracy. Again, in the regular work of a metrology bureau, accurate comparison of the size of an end-standard of length with reference to a line-standard is required. Until 1906 the only apparatus available for these purposes was the measuring machine made for comparing engineering gauges. In that year the writer described a machine based on the principle of electric touch, which was much more delicate than the older mechanical machines. It also had facilities for exploring the solid under test, to prove its accuracy of figure. This machine has been installed and used in the National Physical Laboratory since 1909. Improvements in it were described later. The present paper gives an outline of an improved machine of the same type embodying the experience gained in using the 1906 machine. The chief novelties are: (1) greater strength in the supporting parts, and consequent rigidity of the whole apparatus; (2) larger and much improved table to carry the solid under test; (3) improved measuring-ends; (4) an innovation for making absolute measurements, whereby the line-standard moves but the reading microscope remains fixed; (5) side girders to relieve the bed of load and so reduce friction, abrasion, and strain.

The virial coefficients of the carbon dioxide-ethylene system I. Pure gases

1964 ◽  
Vol 277 (1371) ◽  
pp. 448-467 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Second Virial Coefficient ◽  
Virial Coefficients ◽  
Direct Determination ◽  
Expansion Method ◽  
National Physical Laboratory ◽  
Intermolecular Potential ◽  
Gaseous Mixtures ◽  
Physical Laboratory ◽  
The Relationship

This paper describes the first part of an investigation of the thermodynamic properties of gases and gaseous mixtures undertaken a few years ago at the National Physical Laboratory, with the main object of providing data on the relationship between the properties of mixtures and those of the pure constituents. The virial coefficients of carbon dioxide and ethylene have been determined by the series-expansion method over the range —10 to 200 °C, and the representation of the results by several forms of intermolecular potential has been investigated. In the case of ethylene it appears that the second virial coefficient may be represented accurately in terms of a Lennard-Jones 6:12 potential, the parameters of which are determined. In the corresponding representation for carbon dioxide there is a small but systematic discrepancy and evidence is adduced that this may be rectified by the introduction of a quadrupole interaction term on the lines of the theory developed by Pople. The value of the quadrupole moment suggested by this calculation proves to be in fairly close agreement with a recent direct determination. Work on the virial coefficients of mixtures of the two gases will be described in a further paper.

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