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in subjects: "Adsorption Heat"

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Materials and Component Development for Advanced Turbine Systems

In order to meet the 2010-2020 DOE Fossil Energy goals for Advanced Power Systems, future oxy-fuel and hydrogen-fired turbines will need to be operated at higher temperatures for extended periods of time, in environments that contain substantially higher moisture concentrations in comparison to current commercial natural gas-fired turbines. Development of modified or advanced material systems, combined with aerothermal concepts are currently being addressed in order to achieve successful operat… more

Date: October 1, 2008

Creator: Alvin, M. A.; Pettit, F.; Meier, G.; Yanar, N.; Chyu, M.; Mazzotta, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Calculation of Reactive-evaporation Rates of Chromia

A methodology is developed to calculate Cr-evaporation rates from Cr2O3 with a flat planar geometry. Variables include temperature, total pressure, gas velocity, and gas composition. The methodology was applied to solid-oxide, fuel cell conditions for metallic interconnects and to advanced-steam turbines conditions. The high velocities and pressures of the advanced steam turbine led to evaporation predictions as high as 5.18 9 10-8 kg/m2/s of CrO2(OH)2(g) at 760 °C and 34.5 MPa. This is equival… more

Date: April 1, 2008

Creator: Holcomb, G. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effects of Temperature Gradients and Heat Fluxes on High-Temperature Oxidation

The effects of a temperature gradient and heat flux on point defect diffusion in protective oxide scales were examined. Irreversible thermodynamics were used to expand Fick’s first law of diffusion to include a heat-flux term—a Soret effect. Oxidation kinetics were developed for the oxidation of cobalt and of nickel doped with chromium. Research is described to verify the effects of a heat flux by oxidizing pure cobalt in a temperature gradient at 900 °C, and comparing the kinetics to isotherma… more

Date: April 1, 2008

Creator: Holcomb, G. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A new approach in ultrapurification of coal by selective flocculation. Progress report, [July 1990]

A relatively pure sample of coal and coal pyrite (free of clays) was provided from the Coal Research Resource Center at VPI, Blackburgh, VA. The samples have been prepared and single mineral flucculation tests are in progress to confirm the selectivity achieved with the previously evaluated flocculents. The mathematical/computational model was used to predict the effect of process parameters such as feed composition and polymer dosage on the yield and selectivity. It is determined that improvem… more

Date: June 1, 1990

Creator: Moudgil, B. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Instrument uncertainty effect on calculation of absolute humidity using dewpoint, wet-bulb, and relative humidity sensors

As part of the US Department of Energy`s Advanced Desiccant Technology Program, the National Renewable Energy Laboratory (NREL) is characterizing the state-of-the-art in desiccant dehumidifiers, the key component of desiccant cooling systems. The experimental data will provide industry and end users with independent performance evaluation and help researchers assess the energy savings potential of the technology. Accurate determination of humidity ratio is critical to this work and an understan… more

Date: April 1998

Creator: Slayzak, S. J. & Ryan, J. P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Numerical estimation of adsorption energy distributions from adsorption isotherm data with the expectation-maximization method

The expectation-maximization (EM) method of parameter estimation is used to calculate adsorption energy distributions of molecular probes from their adsorption isotherms. EM does not require prior knowledge of the distribution function or the isotherm, requires no smoothing of the isotherm data, and converges with high stability towards the maximum-likelihood estimate. The method is therefore robust and accurate at high iteration numbers. The EM algorithm is tested with simulated energy distrib… more

Date: August 1, 1993

Creator: Stanley, B. J. & Guiochon, G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The corrosion of UO2 versus ThO2: a quantum mechanical investigation

Quantum mechanical surface energy calculations have been performed on both uranium dioxide (UO{sub 2}) and thorium dioxide (ThO{sub 2}) (111), (110), and (100) surfaces to determine their relative reactivities. While UO{sub 2} and ThO{sub 2} both have the fluorite structure Fm3m, they differ in that uranium has two dominant oxidation states, U{sup 4+} and U{sup 6+}, while thorium only has one, Th{sup 4+}. Furthermore, UO{sub 2} is an intrinsically weak p-type semi-conductor with a band gap of 2… more

Date: January 11, 2005

Creator: Skomurski, F. N.; Shuller, L. C.; Becker, U. & Ewing, R. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A new model of coal-water interaction and relevance for dewatering. Quarterly technical progress report, 1 September--30 November 1992

The picture that emerges is that there are quite large heat effects associated with low uptakes of solvents by the coal. The fact that the heat of wetting decreases dramatically with uptake has been illustrated many times. The final equilibrium uptake of solvent in a swollen coal probably takes place at near zero partial molar enthalpy of mixing, as we have argued earlier. It would, however, be interesting to establish what sorts of interactions give rise to the high initial heats of mixing. Th… more

Date: December 31, 1992

Creator: Suuberg, E. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Structure and dynamics of dense monolayers of NO adsorbed on Rh(111) in equilibrium with the gas phase in the Torr pressure range

Using Scanning Tunneling Microscopy, we show the phase transition between new structures of NO on Rh(111) in equilibrium with the gas phase near 300K, in the Torr pressure range. Two phases with (2x2)and (3x3) periodicity transform into each other as the pressure and temperature change around the equilibrium P-T line. By measuring P and T at coexistence, we determined the heat of adsorption in the(3x3) structure. From the phase boundary dynamics, the activation energy barrier between phases was… more

Date: November 1, 2000

Creator: Rider, Keith B.; Hwang, Kevin S.; Salmeron, Miquel & Somorjai, Gabor A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Not-In-Kind Technologies for Residential and Commercial Unitary Equipment

This project was initiated by the Department of Energy in response to a request from the HVAC industry for consolidated information about alternative heating and cooling cycles and for objective comparisons of those cycles in space conditioning applications. Twenty-seven different heat pumping technologies are compared on energy use and operating costs using consistent operating conditions and assumptions about component efficiencies for all of them. This report provides a concise summary of th… more

Date: January 11, 2001

Creator: Fischer, S.K.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Hydrogen Chemisorption on Pt Single Crystal Surfaces in Acidic Solutions

Hydrogen chemisorption from dilute acidic solution onto Pt single crystal surfaces was examined using an electrochemical cell directly coupled to LEED/Auger analytical system. No pre-anodization was used prior to observing hydrogen adsorption by cyclic voltammetry so that clean surfaces having the ordered structures indicated by LEED were studied. The problem of contributions from non-ordered parts of the electrode like support wires and edges was solved by using a gold evaporation masking tech… more

Date: April 1, 1980

Creator: Ross, Philip N., Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

A new model of coal-water interaction and relevance for dewatering. Quarterly technical progress report, December 1, 1991--February 28, 1992

The possibility that coal holds a significant portion of its moisture by solvent swelling mechanisms leads to an interesting technical issue. It is well known that simple drying of low rank coals at minemouth is ineffective because the process is reversible, to a significant degree. The economic advantages of pre-shipment drying have however dictated a search for ``permanent`` drying procedures. These have been developed by largely empirical means, and involve mild pyrolytic treatments of the c… more

Date: September 1, 1992

Creator: Suuberg, E. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Atomic-Scale Design of Iron Fischer-Tropsch Catalysts: A Combined Computational Chemistry, Experimental, and Microkinetic Modeling Approach

Work continued on the development of a microkinetic model of Fischer-Tropsch synthesis (FTS) on supported and unsupported Fe catalysts. The following aspects of the FT mechanism on unsupported iron catalysts were investigated on during this third year: (1) the collection of rate data in a Berty CSTR reactor based on sequential design of experiments; (2) CO adsorption and CO-TPD for obtaining the heat of adsorption of CO on polycrystalline iron; and (3) isothermal hydrogenation (IH) after Fische… more

Date: September 29, 2006

Creator: Mavrikakis, Manos; Dumesic, James A. & Nabar, Rahul P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Adsorbate structures and catalytic reactions studied in the torrpressure range by scanning tunneling microscopy

High-pressure, high-temperature scanning tunneling microscopy (HPHTSTM) was used to study adsorbate structures and reactions on single crystal model catalytic systems. Studies of the automobile catalytic converter reaction [CO + NO {yields} 1/2 N{sub 2} + CO{sub 2}] on Rh(111) and ethylene hydrogenation [C{sub 2}H{sub 4} + H{sub 2} {yields} C{sub 2}H{sub 6}] on Rh(111) and Pt(111) elucidated information on adsorbate structures in equilibrium with high-pressure gas and the relationship of atomic… more

Date: May 23, 2003

Creator: Hwang, Kevin Shao-Lin

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

open access

Noble Metal Catalysts for Mercury Oxidation in Utility Flue Gas: Gold, Palladium and Platinum Formulations

The use of noble metals as catalysts for mercury oxidation in flue gas remains an area of active study. To date, field studies have focused on gold and palladium catalysts installed at pilot scale. In this article, we introduce bench-scale experimental results for gold, palladium and platinum catalysts tested in realistic simulated flue gas. Our initial results reveal some intriguing characteristics of catalytic mercury oxidation and provide insight for future research into this potentially imp… more

Date: July 1, 2008

Creator: Presto, A. A. & Granite, E. J

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

[Experimental and kinetic modeling of acid/base and redox reactions over oxide catalysts]. Technical progress report

The research has involved the characterization of catalyst acidity, {sup 2}D NMR studies of Bronsted acid sites, and kinetic, calorimetric, and spectroscopic studies of methylamine synthesis and related reactions over acid catalysts. Approach of this work was to explore quantitative correlations between factors that control the generation, type, strength, and catalytic properties of acid sites on zeolite catalysts. Microcalorimetry, thermogravimetric analysis, IR spectroscopy, and NMR spectrosc… more

Date: July 1, 1993

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Sorption and chemical transformation of PAHs on coal fly ash. Final technical report

The objectives of this work were to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAH`s) and their derivatives, and to attempt to understand the influence of surface properties of coal ash in the chemical transformations of PAH`s.

Date: February 1, 1995

Creator: Mamantov, G. & Wehry, E. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Sorption and chemical transformation of PAHs on coal fly ash. Annual technical progress report No. 4, [November 1, 1991--October 31, 1992]

The objective of this research is to characterize the interactions of coal fly ash with polycyclic aromatic hydrocarbons (PAHs) and their derivatives, and to understand the influence of the surface properties of coal ash (and other atmospheric particles) on the chemical transformations of polycyclic aromatic compounds. During the past year the following specific aspects of this broad problem area have been investigated: (a) Fractionation of heterogeneous coal fly ash samples into different part… more

Date: December 31, 1992

Creator: Mamantov, G. & Wehry, E. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Studies of N{sub 2}0 adsorption and decomposition on Fe-ZSM-5

The interactions of N2O with H-ZSM-5 and Fe-ZSM-5 have been investigated using infrared spectroscopy and temperature-programmed reaction. Fe-ZSM-5 samples with Fe/Al ratios of 0.17 and 0.33 were prepared by solid-state exchange. It was determined that most of the iron in the samples of Fe-ZSM-5 is in the form of isolated cations, which have exchanged with Bronsted acid H+ in H-ZSM-5. The infrared spectrum of N2O adsorbed on H-ZSM-5 at 298 K exhibits bands at 2226 and 1308 cm-1 associated with v… more

Date: March 8, 2002

Creator: Wood, Benjamin R.; Reimer, Jeffrey A. & Bell, Alexis T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

CO2 SEPARATIONS USING ZEOLITE MEMBRANES

Zeolite and other inorganic molecular sieve membranes have shown potential for separations based on molecular size and shape because of their small pore sized, typically less than 1 nm, and their narrow pore size distribution. The high thermal and chemical stability of these inorganic crystals make them ideal materials for use in high temperature applications such as catalytic membrane reactors. Most of the progress with zeolite membranes has been with MFI zeolites prepared on porous disks and … more

Date: June 30, 2001

Creator: Noble, Richard D. & Falconer, John L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The Effect of Chemical Additives on the Synthesis of Ethanol. Technical Progress Report 5, September 16, 1988--December 15, 1988

The objective of this research is to elucidate the role of various chemical additives on ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used will include S, P, Ag, Cu, Mn, and Na. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of studies including temperature programmed desorption, infrared st… more

Date: February 4, 1989

Creator: Chuang, S. S. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The Effect of Chemical Additives on the Synthesis of Ethanol. Technical Progress Report No. 8, June 16, 1989--September 15, 1989

The objective of this research is to elucidate the role of various chemical additives on ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used for this study will include S, P, Ag, Cu, Mn, and Na which have different lectronegativities. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of experimen… more

Date: December 20, 1989

Creator: Chuang, S. S. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Sorption and chemical transformation of PAHs on coal fly ash. Technical progress report No. 3, May 1--July 31, 1992

The results obtained to date indicate that toluene is a useful ``probe solute`` for measuring the relative affinities of various fly ash fractions for aromatic solutes. In general, the adsorption isotherms obtained for toluene on fly ash fractions can be fit to a Freundlich adsorption isotherm equation, which implies that the adsorbent surface in question is heterogeneous. For most fly ash fractions studied thus far, the measured heat of adsorption decreases as the quantity of toluene injected … more

Date: October 1, 1992

Creator: Mamantov, G. & Wehry, E. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The Effect of Chemical Additives on the Synthesis of Ethanol. Technical Progress Report No. 4, June 16, 1988--September 15, 1988

The objective of this research is to elucidate the role of various chemical additives on ethanol synthesis over Rh- and Ni-based catalysts. Chemical additives used for this study will include S, P, Ag, Cu, Mn, and Na which have different electronegativities. The effect of additives on the surface state of the catalysts, heat of adsorption of reactant molecules, reaction intermediates, reaction pathways, reaction kinetics, and product distributions is/will be investigated by a series of experime… more

Date: November 14, 1988

Creator: Chuang, S. S. C.

Item Type: Report

Partner: UNT Libraries Government Documents Department