59 research outputs found
The use of yeast inoculation in fermentation for port production; effect on total potential ethyl carbamate
A commercial wine yeast Saccharomyces cerevisiae UCD 522 (pre-cultured in the presence of certain mass-labelled amino acids) was inoculated into a port must which was then allowed to ferment under controlled conditions of temperature and agitation. The influence of potential ethyl carbamate (EC) precursor formed due to yeast pre-culture, upon total potential EC levels was studied at various stages of fermentation. Pre-culture accumulation did not give rise to detectable levels of EC precursor during port fermentation
Pulse-shape discrimination and energy resolution of a liquid-argon scintillator with xenon doping
Liquid-argon scintillation detectors are used in fundamental physics
experiments and are being considered for security applications. Previous
studies have suggested that the addition of small amounts of xenon dopant
improves performance in light or signal yield, energy resolution, and particle
discrimination. In this study, we investigate the detector response for xenon
dopant concentrations from 9 +/- 5 ppm to 1100 +/- 500 ppm xenon (by weight) in
6 steps. The 3.14-liter detector uses tetraphenyl butadiene (TPB) wavelength
shifter with dual photomultiplier tubes and is operated in single-phase mode.
Gamma-ray-interaction signal yield of 4.0 +/- 0.1 photoelectrons/keV improved
to 5.0 +/- 0.1 photoelectrons/keV with dopant. Energy resolution at 662 keV
improved from (4.4 +/- 0.2)% ({\sigma}) to (3.5 +/- 0.2)% ({\sigma}) with
dopant. Pulse-shape discrimination performance degraded greatly at the first
addition of dopant, slightly improved with additional additions, then rapidly
improved near the end of our dopant range, with performance becoming slightly
better than pure argon at the highest tested dopant concentration. Some
evidence of reduced neutron scintillation efficiency with increasing dopant
concentration was observed. Finally, the waveform shape outside the TPB region
is discussed, suggesting that the contribution to the waveform from
xenon-produced light is primarily in the last portion of the slow component
Saint or Sinner?: A Reconsideration of the Career of Prince Alexandre de Merode, Chair of the International Olympic Committeeâs Medical Commission, 1967-2002
This article explores the role of Prince Alexandre de Merode in heading the IOCâs fight against drugs from the 1960s to 2002. History has not served de Merode very well. He has been presented in simplistic ways that emerge from context rather than evidence â as either a saint or a sinner. IOC-sanctioned accounts cast him in the mould of the saint: a moral and intelligent man who saved sports from doping. In contrast, sports academics have tended to portray him as a sinner: an ineffectual leader who did not develop either the testing systems or the punishments required to prevent doping and who deliberately concealed evidence of high-profile doping cases. This article assesses both representations before presenting information to support a richer and more complicated interpretation
ELECTROCHEMISTRY OF MOLTEN SALTS. Period Covered: June 1, 1954 to June 1, 1956
A new back-emf method for measuring the thermodynamic emf of molten salt cells of the type M/MCl/sub 2/ in molten salt solvent/Cl/sub 2/ is presented. Decomposition potentials are measured in the course of the thermodynamic emf determination. The systems PbCl/sub 2/-ZrCl/sub 2/, LiCl-KCl eutectic, LiCl-KCl- NdCl/sub 3/, MgCl/sub 2/ in LiClKCl and NaCl, SnCl/sub 2/, KCl, and PbCl/sub 2/, and ZnCl/sub 2/ in LiClKCl eutectic were studied. The thermodynamic emf's obtained by the back-emf method are in good agreement with values calculated from independent thermochemical data. Thus Raoult's law is thought to apply in these simple systems to within a factor of two in the activity coefficient. (auth
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