47 Matching Results

Search Results

Advanced search parameters have been applied.
in subjects: "Chemical Reaction Kinetics"  
Results: 1 - 24 next
open access

COAL CONVERSION WASTEWATER TREATMENT BY CATALYTIC OXIDATION IN SUPERCRITICAL WATER

Description: Wastewaters from coal-conversion processes contain phenolic compounds in appreciable concentrations. These compounds need to be removed so that the water can be discharged or re-used. Catalytic oxidation in supercritical water is one potential means of treating coal-conversion wastewaters, and this project examined the reactions of phenol over different heterogeneous oxidation catalysts in supercritical water. More specifically, we examined the oxidation of phenol over a commercial catalyst and… more
Date: October 18, 1999
Creator: Savage, Phillip E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Oxidation Reactions of Ethane over Ba-Ce-O Based Perovskites

Description: Ethane oxidation reactions were studied over pure and Ca-, Mg-, Sr-, La-, Nd-, and Y-substituted BaCeO{sub 3} perovskites under oxygen limited conditions. Several of the materials, notably the Ca- and Y-substituted materials, show activity for complete oxidation of the hydrocarbon to CO{sub 2} at temperatures below 650 C. At higher temperatures, the oxidative dehydrogenation (ODH) to ethylene becomes significant. Conversions and ethylene yields are enhanced by the perovskites above the thermal … more
Date: August 18, 1999
Creator: Miller, James E.; Sault, Allen G.; Trudell, Daniel E.; Nenoff, Tina M.; Thoma, Steven G. & Jackson, Nancy B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Kinetics of Reactive Wetting

Description: The importance of interfacial processes in materials joining has a long history. A significant amount of work has suggested that processes collateral to wetting can affect the extent of wetting and moderate or retard wetting rate. Even very small additions of a constituent, known to react with the substrate, cause pronounced improvement in wetting and are exploited in braze alloys, especially those used for joining to ceramics. The wide diversity of processes, such as diffusion, chemical reacti… more
Date: September 9, 1999
Creator: YOST, FREDERICK G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Kinetics of Reaction Between Plutonium Dioxide and Water at 25 C to 350 C: Formation and Properties of the PuO{sub 2+X} Phase

Description: Results of microbalance, pressure-volume-temperature, and mass spectrometric measurements show that a higher oxide of plutonium, PuO{sub 2+x}, and hydrogen are formed by reaction of plutonium dioxide with water at 25 C to 350 C. PuO{sub 2+x} has an intense green color consistent with the presence of Pu(VI). An oxide composition in excess of PuO{sub 2.25} is identified, but the maximum value of x is undefined. Reaction rates derived from linear mass-time and pressure-time data are described by a… more
Date: May 1, 1999
Creator: Morales, Luis A.; Haschke, John M. & Allen, Thomas H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Investigation of Oxidative Degradation in Polymers Using (17)O NMR Spectroscopy

Description: The thermal oxidation of pentacontane (C{sub 50}H{sub 102}), and of the homopolymer polyisoprene, has been investigated using {sup 17}O NMR spectroscopy. By performing the oxidation using {sup 17}O labeled O{sub 2} gas, it is possible to easily identify degradation products, even at relatively low concentrations. It is demonstrated that details of the degradation mechanism can be obtained from analysis of the {sup 17}O NMR spectra as a function of total oxidation. Pentacontane reveals the wides… more
Date: July 20, 1999
Creator: Alam, Todd M.; Celina, Mathew; Assink, Roger A.; Clough, Roger L.; Gillen, Kenneth T. & R., Wheeler David
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Modular Computer Code for Simulating Reactive Multi-Species Transport in 3-Dimensional Groundwater Systems

Description: RT3DV1 (Reactive Transport in 3-Dimensions) is computer code that solves the coupled partial differential equations that describe reactive-flow and transport of multiple mobile and/or immobile species in three-dimensional saturated groundwater systems. RT3D is a generalized multi-species version of the US Environmental Protection Agency (EPA) transport code, MT3D (Zheng, 1990). The current version of RT3D uses the advection and dispersion solvers from the DOD-1.5 (1997) version of MT3D. As with… more
Date: June 24, 1999
Creator: Clement, T. P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Surface Stoichiometry, Structure, and Kinetics of GaAs MOCVD

Description: We have used reflectance-difference spectroscopy (RDS) to examine the surface phases of GaAs(100) during metalorganic chemical vapor deposition (MOCVD). Since the identities of two important surface phases were unknown, we determined their structure and stoichiometry using a variety of surface science techniques. The Type III phase is a newly characterized As-rich (1 X 2)-CH{sub 3} reconstruction. The Type II phase is a metastable derivative of the Type I phase. RDS also indicates that the surf… more
Date: January 29, 1999
Creator: Baucom, K. C.; Creighton, J. R. & Moffat, H. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

In situ vibrational spectroscopic investigation of C{sub 4} hydrocarbon selective oxidation over vanadium-phosphorus-oxide catalysts

Description: n-Butane selective oxidation over the VPO catalyst to maleic anhydride is the first and only commercialized process of light alkane selective oxidation. The mechanism of this reaction is still not well known despite over twenty years of extensive studies, which can partially be attributed to the extreme difficulties to characterize catalytic reactions real-time under typical reaction conditions. In situ spectroscopic characterization techniques such as Infrared spectroscopy and laser Raman spec… more
Date: May 10, 1999
Creator: Xue, Z.Y.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

In Situ Gaseous Reduction Pilot Demonstration - Final Report

Description: The demonstration of the IGRS approach conducted at SWMU 143 on the White Sands Missile Range has provided information needed to complete a technical performance assessment and cost analysis of the technology. At least 70% of the Cr(VI) present in contaminated sediment at the site was reduced, thus verifying the effectiveness of the approach. Most of the treatment occurred in a zone located from {approximately}4 to 10 ft below ground surface, which appears to be a higher permeability interval. … more
Date: February 23, 1999
Creator: Thornton, E. C.; Phelan, J. M.; Giblin, J. T.; Olsen, K. B.; Miller, R. D. & Gilmore, T. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Origin of the Time-Dependence of Wet Oxidation of AlGaAs

Description: The time-dependence of the wet oxidation of high-Al-content AlGaAs can be either linear, indicating reaction-rate limitation, or parabolic, indicating diffusion-limited rates. The transition from linear to parabolic time dependence can be explained by the increased rate of the formation of intermediate As{sub 2}O{sub 3} vs. its reduction to elemental As. A steadily increasing thickness of the As{sub 2}O{sub 3}-containing region at the oxidation front will shift the process from the linear to th… more
Date: February 15, 1999
Creator: Allerman, A. A.; Ashby, C. I. H.; Bridges, M. M.; Hammons, B. E. & Hou, H. Q.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Thermal Decomposition Characteristics of Orthorhombic Ammonium Perchlorate (o-AP)

Description: Preliminary STMBMS and SEM results of the thermal decomposition of AP in the orthorhombic phase are presented. The overall decomposition is shown to be complex and controlled by both physical and chemical processes. The data show that the physical and chemical processes can be probed and characterized utilizing SEM and STMBMS. The overall decomposition is characterized by three distinguishing features: an induction period, and accelerator period and a deceleratory period. The major decompositio… more
Date: March 1, 1999
Creator: Behrens, R. & Minier, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Chemical Reactivity Testing for the National Spent Nuclear Fuel Program. Quality Assurance Project Plan

Description: This quality assurance project plan (QAPjP) summarizes requirements used by Lockheed Martin Energy Systems, Incorporated (LMES) Development Division at Y-12 for conducting chemical reactivity testing of Department of Energy (DOE) owned spent nuclear fuel, sponsored by the National Spent Nuclear Fuel Program (NSNFP). The requirements are based on the NSNFP Statement of Work PRO-007 (Statement of Work for Laboratory Determination of Uranium Hydride Oxidation Reaction Kinetics.) This QAPjP will ut… more
Date: January 24, 1999
Creator: Newsom, H.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Oxygenates vs. synthesis gas

Description: Methanol synthesis from H{sub 2}/CO has been carried out at 7.6 MPa over zirconia-supported copper catalysts. Catalysts with nominal compositions of 10/90 mol% and 30/70 mol% Cu/ZrO{sub 2} were used in this study. Additionally, a 3 mol% cesium-doped 10/90 catalyst was prepared to study the effect of doping with heavy alkali, and this promoter greatly increased the methanol productivity. The effects of CO{sub 2} addition, water injection, reaction temperature, and H{sub 2}/C0 ratio have been inv… more
Date: April 1, 1999
Creator: Klier, Kamil; Herman, Richard G.; Beretta, Alessandra; Burcham, Maria A.; Sun, Qun; Cai, Yeping et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Diesel Emission Control -- Sulfur Effects (DECSE) Program; Phase I Interim Data Report No. 2: NO{sub x} Adsorber Catalysts

Description: The Diesel Emission Control-Sulfur Effects (DECSE) is a joint government/industry program to determine the impact of diesel fuel sulfur levels on emission control systems whose use could lower emissions of nitrogen oxides (NOx) and particulate matter (PM) from on-highway trucks in the 2002--2004 model years. Phase 1 of the program was developed with the following objectives in mind: (1) evaluate the effects of varying the level of sulfur content in the fuel on the emission reduction performance… more
Date: October 15, 1999
Creator: DOE; ORNL; NREL; EMA & MECA
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Coal conversion wastewater treatment by catalytic oxidation in supercritical water

Description: Wastewaters from coal-conversion processes contain phenolic compounds in appreciable concentrations. These compounds need to be removed so that the water can be discharged or re-used. Catalytic oxidation in supercritical water is one potential means of treating coal-conversion wastewaters, and this project examined the reactions of phenol over different heterogeneous oxidation catalysts in supercritical water. More specifically, the authors examined the oxidation of phenol over a commercial cat… more
Date: October 20, 1999
Creator: Savage, Phillip E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Kinetics and mechanism of the oxidation of alkenes and silanes by hydrogen peroxide catalyzed by methylrhenium trioxide (MTO) and a novel application of electrospray mass spectrometry to study the hydrolysis of MTO

Description: Conjugated dienes were oxidized by hydrogen peroxide with methylrhenium trioxide (MTO) as catalyst. Methylrhenium bis-peroxide was the major reactive catalyst present. Hydroxyalkenes and trisubstituted silane were also tested. Mechanisms for each of these reactions are presented.
Date: November 8, 1999
Creator: Tan, Haisong
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Diesel Emission Control -- Sulfur Effects (DECSE) Program; Phase I Interim Data Report No. 1

Description: The Diesel Emission Control-Sulfur Effects (DECSE) is a joint government/industry program to determine the impact of diesel fuel sulfur levels on emission control systems whose use could lower emissions of nitrogen oxides (NO{sub x}) and particulate matter (PM) from on-highway trucks in the 2002--2004 model years. Phase 1 of the program was developed with the following objectives in mind: (1) evaluate the effects of varying the level of sulfur content in the fuel on the emission reduction perfo… more
Date: August 15, 1999
Creator: DOE; ORNL; NREL; EMA & MECA
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

HCCI in a CFR engine: experiments and detailed kinetic modeling

Description: Single cylinder engine experiments and chemical kinetic modeling have been performed to study the effect of variations in fuel, equivalence ratio, and intake charge temperature on the start of combustion and the heat release rate. Neat propane and a fuel blend of 15% dimethyl-ether in methane have been studied. The results demonstrate the role of these parameters on the start of combustion, efficiency, imep, and emissions. Single zone kinetic modeling results show the trends consistent with the… more
Date: November 5, 1999
Creator: Flowers, D; Aceves, S; Smith, R; Torres, J; Girard, J & Dibble, R
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

REDUCTION OF INHERENT MERCURY EMISSIONS IN PC COMBUSTION

Description: Mercury emission compliance presents one of the major potential challenges raised by the 1990 Clean Air Act Amendments. Simple ways of controlling emissions have not been identified. The variability in the field data suggest that inherent mercury emissions may be reduced if the source of this inherent capture can be identified and controlled. The key mechanisms appear to involve the oxidation of mercury to Hg{sup 2}, generally producing the more reactive HgCl{sub 2}, followed by its capture by … more
Date: August 6, 1999
Creator: Kramlich, John C.; Sliger, Rebecca N. & Going, David J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Diesel combustion: an integrated view combining laser diagnostics, chemical kinetics, and empirical validation

Description: This paper proposes a structure for the diesel combustion process based on a combination of previously published and new results. Processes are analyzed with proven chemical kinetic models and validated with data from production-like direct injection diesel engines. The analysis provides new insight into the ignition and particulate formation processes, which combined with laser diagnostics, delineates the two-stage nature of combustion in diesel engines. Data are presented to quantify events o… more
Date: February 1, 1999
Creator: Akinyami, O C; Dec, J E; Durrett, R P; Flynn, P F; Hunter, G L; Loye, A O et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

EFFECTS OF FLY ASH ON MERCURY OXIDATION DURING POST COMBUSTION CONDITIONS

Description: Tests were performed in simulated flue gas streams using two fly ash samples from the electrostatic precipitators of two full-scale utility boilers. One fly ash was derived from a Powder River Basin (PRB) coal, while the other was derived from Blacksville coal (Pittsburgh No. 8 seam). The tests were performed at temperatures of 120 and 180 C under different gas compositions. Elemental mercury (Hg) streams were injected into the simulated flue gas and passed over filters (housed in a convection … more
Date: October 1, 1999
Creator: Norton, Glenn A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Final Report: Catalytic Hydrocarbon Reactions over Supported Metal Oxides, August 1, 1995 - July 31, 1999

Description: The research program focused on the catalysis of hydrodesulfurization (HDS) over molybdenum-based catalysts and how catalyst composition, redox ability, structure and neighboring sites control the catalytic properties of metal oxides. We sought to understand the catalytic features/sites that control hydrogenation, hydrogenolysis, and isomerization during HDS. Unprompted silica-supported molybdenum oxides and molybdenum sulfides were studied. Model catalyst systems were prepared from organometal… more
Date: July 31, 1999
Creator: Ekerdt, John G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
Back to Top of Screen