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Synthesis Of A Low-Carbonate High-Charge Hydrotalcite-Like Compound At Ambient Pressure And Atmosphere, Ravi K. Kukkadapu, Marc S. Witkowski, James E. Amonette Jan 1997

Synthesis Of A Low-Carbonate High-Charge Hydrotalcite-Like Compound At Ambient Pressure And Atmosphere, Ravi K. Kukkadapu, Marc S. Witkowski, James E. Amonette

US Department of Energy Publications

Hydrotalcite (HT), a clay mineral, is constructed of brucite-like layers [Mg(OH)2] in which substitution of Al3+ for Mg2+ at a mole ratio of 1:3 yields a net positive charge. This layer charge is compensated by exchangeable CO3 2- anions located (along with adsorbed water molecules) in the interlayer region. Numerous analogues of HT [i.e., “hydrotalcite-like” compounds (HTLCs)] have been synthesized with a variety of M2+/M3+ combinations,M2+/M3+ ratios, and interlayer anions.1-10 The compositions of these HTLCs are usually expressed using a generalized form of the formula for a substituted brucite, …


Byproduct Formation During The Reduction Of Tce By Zero-Valence Iron And Palladized Iron, Liyuan Liang, Nic Korte, J. D. Goodlaxson, Jay Clausen, Quintus Fernando, Rosy Muftikian Jan 1997

Byproduct Formation During The Reduction Of Tce By Zero-Valence Iron And Palladized Iron, Liyuan Liang, Nic Korte, J. D. Goodlaxson, Jay Clausen, Quintus Fernando, Rosy Muftikian

US Department of Energy Publications

Trichlorothene (TCE) was reduced with zero-valence iron and palladized iron in zero-head-space extractors. Progress of the reaction in these batch studies was monitered with purge-and-trap gas chromatography and a flame ionization detector. When a 5 ppm initial concentration of TCE reacts with zero-valence iron, approximately 140 ppb of vinyl chloride persists for as long as 73 days. The concentration of vinyl chloride (approximately 10 ppb) remaining with palladized iron is approximately and order of magnitude less than when zero-valence iron is the reductant. These data suggest that volatile byproducts may be under-represented in other published data regarding reduction in zero-valence …


A Lagrangian Dispersion Model For Predicting Co2 Sources, Sinks, And Fluxes In A Uniform Loblolly Pine (Pinus Taeda L.) Stand, Gabriel Katul, Ram Oren, David Ellsworth, Cheng-I Hsieh, Nathan Phillips, Keith Lewin Jan 1997

A Lagrangian Dispersion Model For Predicting Co2 Sources, Sinks, And Fluxes In A Uniform Loblolly Pine (Pinus Taeda L.) Stand, Gabriel Katul, Ram Oren, David Ellsworth, Cheng-I Hsieh, Nathan Phillips, Keith Lewin

US Department of Energy Publications

A canopy Lagrangian turbulent scalar transport model for predicting scalar fluxes, sources, and sinks within a forested canopy was tested using CO2 concentration and flux measurements. The model formulation is based on the localized near-field theory (LNF) proposed by Raupach [1989a, b]. Using the measured mean CO2 concentration profile, the vertical velocity variance profile, and the Lagrangian integral timescale profile within and above a forested canopy, the proposed model predicted the CO2 flux and source (or sink) profiles. The model testing was carried out using eddy correlation measurements at 9 m in a uniform 13 m tall …


Runoff, Erosion, And Soil Quality Characteristics Of A Former Conservation Reserve Program Site, John E. Gilley, John W. Doran, Douglas Karlen, T. C. Kaspar Jan 1997

Runoff, Erosion, And Soil Quality Characteristics Of A Former Conservation Reserve Program Site, John E. Gilley, John W. Doran, Douglas Karlen, T. C. Kaspar

Department of Biological Systems Engineering: Papers and Publications

No-till and moldboard plow tillage systems were established on a former Conservation Reserve Program (CRP) site in southwest Iowa. Runoff rates from simulated rainfall events were significantly greater on sites returned to crop production than from adjoining, undisturbed CRP areas. Substantial soil loss was measured from the moldboard plow treatments, but no significant differences in erosion rates were found between the undisturbed CRP and no-till management systems. No-till management maintained levels of soil quality similar to those of CRP by preserving soil structural integrity and reducing losses of soil organic matter (SOM) associated with tillage. Conservation tillage systems which maintain …