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Search Publications by: James W. Schmidt (Assoc)

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Displaying 26 - 50 of 67

Capacitors and Electromagnetic Resonators for Gas Metrology

May 1, 2007
Author(s)
Michael R. Moldover, James W. Schmidt
Gas-filled capacitors are being used as primary thermometers and they show promise as primary pressure standards and for measuring the Boltzmann constant. With these metrological applications in mind, we discuss the advantages and disadvantages of audio

A Primary Dead-Weight Tester for Pressures (0.05-1.0) MPa

April 1, 2003
Author(s)
K. Jain, Walter J. Bowers Jr., James W. Schmidt
Recent advances in technology on two fronts, 1) the fabrication of large diameter pistons and cylinders with good geometry, and 2) the ability to measure the dimensions of these components with high accuracy, have allowed dead-weight testers at NIST to

Dielectric Permittivity of Eight Gases Measured with Cross Capacitors

March 1, 2003
Author(s)
James W. Schmidt, Michael R. Moldover
A 4-ring, toroidal cross capacitor was used to measure accurately the relative dielectric permittivity ε(p,T) of He, Ar, N 2, O 2, CH 4, C 2H 6, C 3H 8, and CO 2. (ε is often called the dielectric constant. ) The data are in the range from 0 C to 50 C and

A Double-Primary Dead-Weight Tester for Pressures (35-175) kPa in Gage Mode

February 1, 2003
Author(s)
K. Jain, Y Q. Cen, Walter J. Bowers Jr., James W. Schmidt
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 have also

NCSL Pressure Comparison At 0.69 Mpa (100 psi) and 1.4 Mpa (200 psi)

July 1, 2000
Author(s)
Robert G. Driver, James W. Schmidt
The pressure and Vacuum Group at NIST has piloted a pressure comparison under the auspices of the Measurement comparison program committee for the NCSL. A 1.4 MPa (~200 psi)transducer package used as a transfer standard was circulated among 20 domestic

A primary pressure standard at 100 kPa

June 1, 1999
Author(s)
James W. Schmidt, Y Q. Cen, Robert G. Driver, Walter J. Bowers Jr., J C. Houck, S A. Tison, Charles D. Ehrlich
Primary pressure standards in the atmospheric pressure range are often established using mercury manometers. To a lesser extent controlled-clearance dead-weight testers in which one component (normally the piston) has been dimensionally measured have also