Matthew E. Briggs

Publications (6)4.7 Total impact

• Article: Second Flight of the Zeno Experiment on USMP-3

  Robert W. Gammon, J. N. Shaumeyer, Matthew E. Briggs, Hacene Boukari, David Gent, R. Allen Wilkinson
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  ABSTRACT: The second flight of the Zeno experiment in the USMP-3 flight has shown successful control of density perturbations near the window surfaces. These density changes were demonstrated to be arising from the rate of temperature change in the sample cell during the flight. These effects could be controlled by using decreasing ramp rates as Tc was approached. The cell window interference was carefully recorded to provide data about the phase of the interference close to the critical point and the effective window reflectivity. Correlograms were recorded from 500 mili K down to 2 mili K at 24 temperatures, 383 correlograms in all. The efforts to get closer were prevented by a long (greater than two week time constant) decay of a 1.3% density error caused by local heating from the 17 micro W laser beam. The phase boundary was located with unprecedented precision of +/- 2O micro K. The complete experiment sequence was done with ground commanding and uploaded script files, bypassing the original autonomous-mode program sequence.
  12/1998;
• Article: Zeno: Critical Fluid Light Scattering Experiment

  Robert W. Gammon, J. N. Shaumeyer, Matthew E. Briggs, Hacene Boukari, David A. Gent, R. Allen Wilkinson
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  ABSTRACT: The Zeno (Critical Fluid Light Scattering) experiment is the culmination of a long history of critical fluid light scattering in liquid-vapor systems. The major limitation to making accurate measurements closer to the critical point was the density stratification which occurs in these extremely compressible fluids. Zeno was to determine the critical density fluctuation decay rates at a pair of supplementary angles in the temperature range 100 mK to 100 (mu)K from T(sub c) in a sample of xenon accurately loaded to the critical density. This paper gives some highlights from operating the instrument on two flights March, 1994 on STS-62 and February, 1996 on STS-75. More detail of the experiment Science Requirements, the personnel, apparatus, and results are displayed on the Web homepage at http://www.zeno.umd.edu.
  10/1996;
• Article: Erratum: The susceptibility critical exponent for a nonaqueous ionic binary mixture near a consolute point [J. Chem. Phys. 97, 8692 (1992)]

  Kaichang J. Zhang, Matthew E. Briggs, Robert W. Gammon, J. M. H. Levelt Sengers
  The Journal of Chemical Physics 09/1996; 105(10):4397-4397. · 3.33 Impact Factor
• Article: Measurement of the temperature coefficient of ratio transformers

  Matthew E. Briggs, Robert W. Gammon, J. N. Shaumeyer
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  ABSTRACT: We have measured the temperature coefficient of the output of several ratio transformers at ratios near 0.500 000 using an ac bridge and a dual‐phase, lock‐in amplifier. The two orthogonal output components were each resolved to ±1 ppb of the bridge drive signal. The results for three commercial ratio transformers (an ESI DT72A, a Gertsch RT‐1665u, and an Eaton PRT‐10C) between 20 and 50 °C range from 0.5 to 100 ppb/K for the signal component in phase with the bridge drive, and from 4 to 300 ppb/K for the quadrature component.
  Review of Scientific Instruments 04/1993; · 1.37 Impact Factor
• Article: The susceptibility critical exponent for a nonaqueous ionic binary mixture near a consolute point

  Kai C. Zhang, Matthew E. Briggs, Robert W. Gammon, J. M. H. Levelt Sengers
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  ABSTRACT: We report turbidity measurements of a nonaqueous ionic solution of triethyl n-hexylammonium triethyl n-hexylboride in diphenyl ether. A classical susceptibility critical exponent gamma = 1.01 +/- 0.01 is obtained over the reduced temperature range t between values of 0.1 and 0.0001. The best fits of the sample transmission had a standard deviation of 0.39 percent over this range. Ising and spherical model critical exponents are firmly excluded. The correlation length amplitude xi sub 0 from fitting is 1.0 +/- 0.2 nm which is much larger than values found in neutral fluids and some aqueous binary mixtures.
  01/1993;
• Article: Critical speeding up in pure fluids

  Hacene Boukari, J. N. Shaumeyer, Matthew E. Briggs, Robert W. Gammon
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  ABSTRACT: The extreme compressibility of a pure fluid near its critical point significantly affects its bulk dynamic response to temperature changes through adiabatic processes. Equations that describe the dynamics in the absence of gravity are developed, and the magnitude of the effect is illustrated with numerical solutions in one dimension. The results are remarkable: 5 mm of critical xenon, quenched from 20 to 10 mK above its critical temperature, cools by over 99 percent in less than 5 s. Moreover, adiabatic cooling is faster when the fluid is closer to the critical point.
  03/1990;