When work in photometry was initiated at the National Bureau of Standards (NBS) around 1903, a group of carbon-filament lamps calibrated against Hefner flame standards were set up as the first National Reference Standard of luminous intensity. ...
This is one of a group of standard inductors purchased by the National Bureau of Standards (NBS) in 1904 from several German makers. It is number #895. The design had been proposed by German physicist Max Wien in 1896. Insulated copper wire was...
This instrument was manufactured by the Cambridge Scientific Instrument Company of Cambridge, England under William Duddell's U.K. Patent DG42-1900. It is a combination of a heated wire and a thermocouple, which measures the temperature rise caused...
Electricity; Galvanometer; Radiometry; Electric currents
This five-dial type resistance box, having a total resistance of 20,000 ohms, is typical of the construction of the best laboratory equipment at the time it was purchased by the National Bureau of Standards in 1904. It was used to adjust the...
Blocks; combinatorics; examples of graphs; graph theory; minimal blocks; planar graphs; thickness of graphs; two-connected graphs
In this paper we provide a catalog of the minimal blocks with 10 and fewer vertices, together with a discussion of the methods and theorems used to produce the catalog. In addition, we prove a theorem which is a strengthening of a similar theorem...
Enhancement factor; equation of state; interaction virial coefficients; moist air; saturated air; second virial coefficients; virial coefficients
Experimental measurements of the enhancement factors for mixtures of water vapor and CO2-free air have been made at -20, -10, and +70 C. The results, coupled with previous experimental enhancement data, have been used to calculate the second...
Performance requirements are detailed for robust fast-operating 50-pound balances precise to 1 part in about 500,000, under less than ideal weighing conditions. Careful studies of design and configuration of large-capacity balances lead to the...
Primary pressure standards in the atmospheric pressure range are often established using mercury manometers. Less frequently, controlled-clearance dead-weight testers in which one component ( normally the piston) has been dimensionally measured...
This paper describes an experimental ""dual centrifuge"" in which an accelerometer being calibrated is carried around a circular path in a horizontal plane. If the instrument is constrained to have nonrotational motion, such as is provided by a...
Boron-10; boron-11; dimethoxyborane; proton; pulsed nuclear magnetic resonance; scalar and quadrupolar coupling constants and relaxation effects
Proton and boron-11 c.w. nuclear magnetic resonances have been studied in solid H11B(OCD3)2 and H10B(OCD3)2. For 11B, only the - ? transition, broadened by second order quadrupolar effects and by proton dipolar interaction can be seen; from the...
A recently developed radiometer system NCS1 is used to calibrate thermal noise temperature at any frequency between 1.0 GHz and 12.0 GHz. Any cryogenic noise source can be measured; the upper limit of noise temperatures measured without a loss of...
To supplement information given in an earlier paper (J. Res. NBS 66C (Eng. and Instr.) No. 1, 33 (1962)) a Pienkowsky-type series is presented for the calibration of a set of weights having a combined mass of 10 units and individual masses of 5, 2,...
