Characterization of surface carbon formed during the conversion of methane to benzene over Mo/H-ZSM-5 catalysts

During the conversion of methane to benzene in the absence of oxygen over a 2 wt% Mo/H-ZSM-5 catalyst at 700 °C, three different types of surface carbon have been observed by X-ray photoelectron spectroscopy: adventitious or graphitic-like C (284.6 eV), carbidic-like C (282.7 eV), and hydrogen-poor sp-type C (283.2 eV), where the C 1s binding energies for the respective forms of carbon are given in parentheses. Pretreatment of the catalyst at 700 °C in CO also resulted in a strong signal at 283.2 eV; thus, the species responsible for this signal appears to be different from the usual aromatic-type coke. The coke with dominantly sp hybridization is concentrated on the external surface of the zeolite and is responsible for the gradual deactivation of the catalyst

Destructive Adsorption of Carbon Tetrachloride on Alkaline Earth Metal Oxides

The destructive adsorption of CCl4 on MgO, CaO, SrO, and BaO has been studied as a function of the reaction temperature and the amount of CCl4 injected. The reaction was followed using in situ Raman spectroscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and 13 C magic angle spinning nuclear magnetic resonance spectroscopy. It was found that the activity toward CCl4 parallels the basicity of the alkaline earth metal oxide; i.e., the activity decreased in the order BaO > SrO > CaO > MgO. Barium oxide readily reacted with CCl4 at 200-300 °C, and, at these low temperatures, CO2 was the only gas-phase product that evolved from the surface. At higher reaction temperatures, other alkaline earth metal oxides, such as CaO and MgO, also became active, and COCl2 was found to be a reaction intermediate in the destruction of CCl4. Although the destruction process is initiated at the surface, the continuous O 2- /Cl - exchange results in the bulk transformation of the metal oxide to the metal chloride. Barium oxide could be regenerated by dissolving the chloride in water, followed by precipitation as barium carbonate and subsequent calcination. In addition, carbon tetrachloride destruction at around 600 °C resulted in the formation of an unusual alkaline earth metal oxide chloride, viz., M4OCl6 (M ) Ba, Sr, or Ca)

Measuring the value of graduate information technology education for Marine Officers: a proof of concept study

This research examines a process to estimate the value of graduate education. Moreover, it demonstrates an approach to measuring the use of graduate education within organizations. Marine Corps officers who graduated from the Naval Postgraduate School's Information System Technology curriculum are studied. The study used a web-based survey for data collection and a Knowledge Value Added method to objectively estimate the value of education topics across different Marine Corps processes. Results indicate that the Information System Technology curriculum is designed and implemented to successfully meet sponsor requirements. It reveals that the education is highly valued and frequently used in post graduation billets. The most valued aspect of the education is theoretical knowledge. However, the research showed how practical information technology skills and social relationships that developed during the resident education were also highly valued and frequently used. The results go on to show that personal interest in education topics often corresponded to greater perceived value. Lastly, a proof of concept demonstrates a method to measure and compare the use on graduate education in subsequent organizational processes. The Knowledge Value Added method provides the ability to compare education use between different topics, across different jobs, and between different people.http://archive.org/details/measuringvalueof109454247Major, United States Marine CorpsApproved for public release; distribution is unlimited

Transition metal-graphite catalysts for production of light hydrocarbons from synthesis gas. Interim report, August 1, 1976-April 30, 1978

The unusual and potentially significant selectivity behaviors exhibited by iron- and, particularly, cobalt-graphite intercalates during CO hydrogenation warrant continued investigation, using a differential/integral flow-type reactor capable of operating at elevated reaction pressure, i.e., 0 to 300 psig. Such a system will enable further characterization of these catalysts to be made in at least three important, but heretofore unexamined, areas: this will permit the rapid acquisition of such important data as comparative turnover frequencies and apparent activation energies for CO conversion. The accuracy, convenience, and flexibility of the measurements will be greatly improved with a flow-type reaction system. Measurements of deactivation properties perforce require the use of a flow reactor and cannot be meaningfully made using a closed reaction system. Particular emphasis will be placed on establishing the effects of varying pretreatment conditions on activity/selectivity responses of the graphitic materials compared to their supported homologs. Additional information about catalyst coking properties and consequent mass balances will also be obtainable from such experiments. The most important information accessible by an elevated-pressure flow reactor are the comparative dependences of product selectivities on reaction pressure for both pairs of catalysts. In view of the already greater tendency of iron- and cobalt-graphite catalysts to produce longer average product molecules than their spported counterparts, even at one atmosphere pressure, it is of obvious importance to determine whether this behavior persists at higher reaction pressures. The situation for cobalt-graphite will be of particular interest because of its unusually constant selectivity properties over a 100/sup 0/C range of reaction temperatures