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Jon R. Pratt (Fed)

Dr. Pratt is a mechanical engineer and Chief of the Quantum Measurement Division of the Physical Measurement Laboratory (PML) at the National Institute of Standards and Technology (NIST).


Measuring the frequency of a pendulum

Jon R. Pratt, Stephan Schlamminger, Charles Condos, Jack Manley, Dalziel Wilson
We previously reported the use of a chip-scale torsion pendulum as a clock gravimeter, exploiting the parametric coupling of its frequency to the local

The Design of an Instrument to Realize Small Torque at NIST

Leon S. Chao, Rafael Marangoni, Frank C. Seifert, Darine El Haddad, Jon R. Pratt, David B. Newell, Stephan Schlamminger
After the recent redefinition of the International System of Units (SI), torque no longer needs to be traceable to a calibrated mass in a gravitational field

Contributions of precision engineering to the revision of the SI

Stephan Schlamminger, Harald Bosse, Horst Kunzmann, Jon R. Pratt, Ian Robinson, Michael de Podesta, Paul Shore, Paul Morantz
All measurements performed in science and industry are based on the International System of Units, the SI. It has been proposed to revise the SI following an

Patents (2018-Present)

Absolute Mass Balance

NIST Inventors
Leon Chao and Jon R. Pratt
An absolute mass balance determines an absolute mass of an object and includes: a dual diameter wheel including: a balance fulcrum; and a balance beam disposed on the balance fulcrum and including: a main mass arm and a counter mass arm; a main mass receiver that receives the object; a main magnet

Optomechnical Gravimeter

NIST Inventors
Jacob Taylor and Jon R. Pratt
An optomechanical gravimeter includes: a first and second accelerometer; and a spacer member interposed between the first accelerometer and the second accelerometer such that the first accelerometer and the second accelerometer independently include: a basal member; a test mass disposed on the basal
Created August 27, 2019, Updated December 8, 2022