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Bioresource and Agricultural Engineering

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University of Nebraska - Lincoln

1999

Articles 1 - 7 of 7

Full-Text Articles in Engineering

Method And Apparatus For Production Of Levulinic Acid Via Reactive Extrusion, Viswasrao Ghorpade, Milford Hanna Jan 1999

Method And Apparatus For Production Of Levulinic Acid Via Reactive Extrusion, Viswasrao Ghorpade, Milford Hanna

Industrial Agricultural Products Center: Publications and Information

The present invention relates to a continuous process for preparing levulinic acid from starch in a reactive extrusion process. In a preferred embodiment, the extrusion takes place in a twin-screw extruder having a plurality of temperature zones wherein the starch slurry is preconditioned, extruded, filter pressed, reboiled, vacuum distilled, condensed, centrifuged, whereby the waste effluent from the centrifugation is reprocessed upstream to the preconditioning stage.


2h Solid-State Nmr Investigation Of Terephthalate Dynamics And Orientation In Mixed-Anion Hydrotalcite-Like Compounds, Robert S. Maxwell, Ravi K. Kukkadapu, James E. Amonette, Herman Cho Jan 1999

2h Solid-State Nmr Investigation Of Terephthalate Dynamics And Orientation In Mixed-Anion Hydrotalcite-Like Compounds, Robert S. Maxwell, Ravi K. Kukkadapu, James E. Amonette, Herman Cho

US Department of Energy Publications

The dynamics and orientations of interlayer terephthalate (TA) anions in mixed-anion hydrotalcite-like compounds [Mg1-x Alx(OH)2](AyB1-y)x/2nH2O, where A = p-C6D4(COO)22- and B ) CO32-] were investigated by 2H variable-temperature solid-state nuclear magnetic resonance (NMR) spectroscopy. Two dominant 003 d spacings, 7.6 and 14.2 Å, were observed by X-ray diffraction (XRD) in these samples, suggesting that there were at least two interlayer environments. Over the range of layer charges studied (0.37 ≥ x ≥ 0.29), the intensity …


Metal Oxide Surfaces And Their Interactions With Aqueous Solutions And Microbial Organisms, Gordon E. Brown Jr., Victor Henrich, William Casey, David Clark, Carrick Eggleston, Andrew Felmy Andrew Felmy, D. Wayne Goodman, Michael Gratzel, Gary Maciel, Maureen I. Mccarthy, Kenneth H. Nealson, Dimitri Sverjensky, Michael Toney, John M. Zachara Jan 1999

Metal Oxide Surfaces And Their Interactions With Aqueous Solutions And Microbial Organisms, Gordon E. Brown Jr., Victor Henrich, William Casey, David Clark, Carrick Eggleston, Andrew Felmy Andrew Felmy, D. Wayne Goodman, Michael Gratzel, Gary Maciel, Maureen I. Mccarthy, Kenneth H. Nealson, Dimitri Sverjensky, Michael Toney, John M. Zachara

US Department of Energy Publications

During the past decade, interest in chemical reactions occurring at metal oxide-aqueous solution interfaces has increased significantly because of their importance in a variety of fields, including atmospheric chemistry, heterogeneous catalysis and photocatalysis, chemical sensing, corrosion science, environmental chemistry and geochemistry, metallurgy and ore beneficiation, metal oxide crystal growth, soil science, semiconductor manufacturing and cleaning, and tribology. The metal oxide-aqueous solution interface is reactive due to acid-base, ligand-exchange, and/or redox chemistry involving protons (hydronium ions), hydroxyl groups, aqueous metal ions, and aqueous organic species and also complexes among these species. Interfacial localization of those species (adsorption) may result from electrostatic, …


Influence Of Aqueous And Solid-Phase Fe(Ii) Complexants On Microbial Reduction Of Crystalline Iron(Iii) Oxides, Matilde Urrutia, Eric E. Roden, John M. Zachara Jan 1999

Influence Of Aqueous And Solid-Phase Fe(Ii) Complexants On Microbial Reduction Of Crystalline Iron(Iii) Oxides, Matilde Urrutia, Eric E. Roden, John M. Zachara

US Department of Energy Publications

The influence of aqueous (NTA and EDTA) and solidphase (aluminum oxide, layer silicates) Fe(II) complexants on the long-term microbial reduction of synthetic goethite by Shewanella alga strain BrY was studied. NTA enhanced goethite reduction by promoting aqueous Fe(II) accumulation, in direct proportion to its concentration in culture medium (0.01-5 mM). In contrast, EDTA failed to stimulate goethite reduction at concentrations e1 mM, and 5 mM EDTA enhanced the final extent of reduction by only 25% in relation to nonchelator controls. The minor effect of EDTA compared to NTA, despite the greater stability of the Fe(II)- EDTA complex, likely resulted from …


Climate Change Impacts On The Potential Productivity Of Corn And Winter Wheat In Their Primary United States Growing Regions, Robert Brown, Norman Rosenberg Jan 1999

Climate Change Impacts On The Potential Productivity Of Corn And Winter Wheat In Their Primary United States Growing Regions, Robert Brown, Norman Rosenberg

US Department of Energy Publications

We calculate the impacts of climate effects inferred from three atmospheric general circulation models (GCMs) at three levels of climate change severity associated with change in global mean temperature (GMT) of 1.0, 2.5 and 5.0 _C and three levels of atmospheric CO2 concentration ([CO2]) – 365 (no CO2 fertilization effect), 560 and 750 ppm – on the potential production of dryland winter wheat (Triticum aestivum L.) and corn (Zea mays L.) for the primary (current) U.S. growing regions of each crop. This analysis is a subset of the Global Change Assessment Model (GCAM) which has …


Below-Ground Respiratory Responses Of Sugar Maple And Red Maple Saplings To Atmospheric Co2 Enrichment And Elevated Air Temperature, Nelson Edwards, Richard Norby Jan 1999

Below-Ground Respiratory Responses Of Sugar Maple And Red Maple Saplings To Atmospheric Co2 Enrichment And Elevated Air Temperature, Nelson Edwards, Richard Norby

US Department of Energy Publications

The research described in this paper represents a part of a much broader research project with the general objective of describing the effects of elevated [CO2] and temperature on tree growth, physiological processes, and ecosystem-level processes. The specific objective of this research was to examine the below-ground respiratory responses of sugar maple (Acer saccharum Marsh.) and red maple (Acer rubrum L.) seedlings to elevated atmospheric [CO2] and temperature. Red maple and sugar maple seedlings were planted in the ground in each of 12 open-top chambers and exposed from 1994 through 1997 to ambient air …


Report Of The Poplar Working Group, Steve Strauss Jan 1999

Report Of The Poplar Working Group, Steve Strauss

US Department of Energy Publications

Poplars consist of all species of the genus Populus, including cottonwoods, aspens, and the many interspecies hybrids in common use (Dickmann and Stuart 1983). Our working group focused on the fungal pathogens, arthropod herbivores, and weed competitors of Populus in the United States. However, bacterial and viral diseases of Populus are significant in Europe, and genetic engineering approaches toward their control or management are being studied. The key aspects of poplar biology important to understanding the use of pest resistance genes are described below.