No description available.

No description available.

No description available.

This research report investigated the ruthenium-catalyzed hydrogenation of aqueous sodium bicarbonate. Subjects of the investigation included: the "blank" effect of the 316 stainless steel reactor in the batch mode; the catalytic activities at 150°C for unsupported ruthenium, including ruthenium purge and the metal produced from the in situ reduction of RuCl3·1-3H2O and Ru(IV)O2·H2O; the catalytic activities at 150°C for supported ruthenium including 4.05% w/w ruthenium on alumina, 5.25 and 20.85%w/w ruthenium on molecular sieve SK-41 (ammonium - substituted Y-type), 3.34 and 17.48% w/w ruthenium on SK-41 (prepared by the in situ reduction of the RuCl3·1-3H2O exchange sieve); orders of reaction rate with respect to hydrogen, bicarbonate, and catalyst at 150°C; activity as a function of temperature; and susceptibility to deactivation. The reaction appears to be zero order in both hydrogen and bicarbonate and first order in catalyst at 150°C in the concentration ranges examined; saturation of an assumed limited number of active catalyst sites is assumed to cause the observed zero orders. Conversion was negligible below 150°C, and optimum in the 150°C-200°C range, with product distribution at 150°C heavily favoring methane; e.g. 99% v/v. The stainless steel reactor was found not to catalyze the reaction at 150°C during a two hour reaction. Catalytic activity for unsupported ruthenium paralleled metal surface area (as determined by BET adsorption), while the inverse was found to be true for sieve-supported metal; mass transfer impedance and electronic effects are assumed to be contributing factors. The reaction on alumina-supported ruthenium produced an undesirable white coating, composition as yet undetermined, which strongly adhered to the support and to the reactor walls. Although the reaction investigated is even more exothermic than the Fischer-Tropsch production of methane, and the ruthenium catalyst was also found to be subject to deactivation, the reaction of interest may have an economic advantage over the Fischer-Tropsch synthesis, in that it is less expensive to decompose a bicarbonate species using hydration energy and then hydrogenate directly, then to thermally decompose the ore and hydrogenate the CO2 produced.

Thesis / Master of Science (MS)

No description available.

Thesis (M.S.)--University of Michigan, 1988.

Dans le cadre du développement des réacteurs de génération IV, une des voies de recherche concerne le développement des réacteurs à neutron rapide à caloporteur sodium. Le CEA a pour projet la construction d'un prototype de réacteur de ce type appelé " ASTRID ". En réponse aux besoins de développement de ce prototype, des recherches sont menées sur la disponibilité et, en particulier, sur la réduction des temps de lavage du sodium résiduel des assemblages de combustible, lors de leur déchargement. En effet, le lavage étant réalisé avec de l'eau, qui est très réactive avec le sodium, celle-ci est amenée de façon très progressive pour le traitement. Une solution alternative, actuellement à l'étude au CEA, et qui fait l'objet de ce mémoire de thèse, consiste en l'utilisation de solutions aqueuses salines permettant de ralentir la cinétique de la réaction du sodium avec l'eau. Ce travail de thèse présente les différents sels évalués et tente d'expliquer leur mécanisme d'action. / Within the framework of the development of generation IV reactors one of the research tracks is related to the development of fast neutron reactors using fluid sodium heat transfer...

No description available.

The objective of this study was to determine the effect of vacuum packaging and 100% CO₂ with and without sodium lactate (0%, 2.4%, 4.8%), sodium acetate (0%, 0.25%, 0.50%), and sodium diacetate (0%, 0.25%, 0.50%) on the inhibition of L. monocytogenes on turkey frankfurters. After 4 weeks at 4°C, the counts of L. monocytogenes did not increase in any treatment, including the control. The use of sodium lactate (4.8%), sodium acetate (0.5%), and sodium diacetate (0.5%) provided approximately a 0.5 log10 CFU/g decrease when compared to the control; however, there was not a significant (P > 0.05) difference between the control and the samples using sodium acetate (0.25%), sodium diacetate (0.25%), or sodium lactate (2.4%). There was also no significant difference between the samples packaged in 100% CO₂ or under vacuum (P > 0.05). After 4 weeks at 10°C, growth of L. monocytogenes was approximately 1-1.5 log lower on the frankfurters packaged in 100% CO₂ than those packaged in a vacuum atmosphere (P £ 0.001). Sodium acetate (0.5%) and sodium lactate (2.4%) in combination with a high CO₂ atmosphere prevented any increase in L. monocytogenes numbers for up to 4 weeks at 10°C. The use of sodium lactate (4.8%) and sodium diacetate (0.5%) in combination with a high CO₂ atmosphere resulted in a decrease in numbers of L. monocytogenes on the frankfurters by ~0.5 log (P £ 0.001). Strict temperature control is needed to prevent the growth of L. monocytogenes. A high CO₂ atmosphere in combination with antimicrobials may assist in keeping the numbers of the organism in the food low in the case of product contamination and temperature abuse. / Master of Science