United States Department of Energy

About: United States Department of Energy is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Coal & Catalysis. The organization has 13656 authors who have published 14177 publications receiving 556962 citations. The organization is also known as: DOE & Department of Energy.

Uncatalyzed and wall‐catalyzed forward water–gas shift reaction kinetics

Abstract: The kinetics of the high-temperature (1070–1134 K), low- and high-pressure gas-phase forward water–gas shift reaction (fWGSR) were evaluated in an empty quartz reactor and a quartz reactor packed with quartz particles. The power-law expression for the reaction rate was consistent with the Bradford mechanism and was invariant with respect to pressure. The experimental rate constant was lower than that published by Graven and Long, and slightly higher than estimates obtained using the reaction rate expression derived from the Bradford mechanism in conjunction with values of reaction rate constants obtained from the GRI database. Similar experiments conducted using a reactor composed of Inconel® 600, a representative reactor shell material, exhibited substantially enhanced rates of reaction. A simple power-law rate expression was incorporated into a surface-catalyzed plug flow reactor (PFR) model to correlate the results between 600 and 900 K. Palladium and palladium–copper alloy surfaces, representative of hydrogen membranes, were also shown to enhance the fWGSR rate, but not as much as the Inconel® 600 surfaces. © 2005 American Institute of Chemical Engineers AIChE J, 2005

Magnetic field effects on transport properties of PtSn4

Abstract: The anisotropic physical properties of single crystals of orthorhombic PtSn${}_{4}$ are reported for magnetic fields up to 140 kOe, applied parallel and perpendicular to the crystallographic b axis. The magnetic susceptibility has an approximately temperature-independent behavior and reveals an anisotropy between the ac plane and b axis. Clear de Haas-van Alphen oscillations in fields as low as 5 kOe and at temperatures as high as 30 K were detected in magnetization isotherms. The thermoelectric power and resistivity of PtSn${}_{4}$ show the strong temperature and magnetic field dependencies. A change of the thermoelectric power at $H=140$ kOe is observed as high as $\ensuremath{\simeq}$50 $\ensuremath{\mu}$V/K. Single crystals of PtSn${}_{4}$ exhibit very large transverse magnetoresistance of $\ensuremath{\simeq}$$5\ifmmode\times\else\texttimes\fi{}{10}^{5}$% for the ac plane and of $\ensuremath{\simeq}$$1.4\ifmmode\times\else\texttimes\fi{}{10}^{5}$% for the b axis resistivity at 1.8 K and 140 kOe, as well as pronounced Shubnikov de Haas oscillations. The magnetoresistance of PtSn${}_{4}$ appears to obey Kohler's rule in the temperature and field range measured. The Hall resistivity shows a linear temperature dependence at high temperatures followed by a sign reversal around 25 K which is consistent with thermoelectric power measurements. The observed quantum oscillations and band structure calculations indicate that PtSn${}_{4}$ has three-dimensional Fermi surfaces.