Search

Your search keyword '"Palmer, Phillip D."' showing total 27 results
Start Over Author "Palmer, Phillip D."
27 results on '"Palmer, Phillip D."'

2. Neptunium and plutonium solubilities in a Yucca mountain groundwater

Author

Efurd, D. Wes, Runde, Wolfgang, Banar, Joe C., Janecky, David R., Kaszuba, John P., Palmer, Phillip D., and Roensch, Fred R.

Subjects
United States. Los Alamos National Laboratory -- Research, Nuclear industry -- Research, Environmental issues, Science and technology
Abstract

Researchers from the Los Alamos National Laboratory in New Mexico performed experiments from the Yucca Mountain Nuclear Waste Repository site, NV for the solubility of neptunium and plutonium.

Published
1998

3. Solubilization of plutonium hydrous oxide by iron-reducing bacteria

Author

Rusin, Patricia A., Quintana, Leticia, Brainard, James R., Strieteimeier, Betty A., Tait, C. Drew, Ekberg, Scott A., Palmer, Phillip D., Newton, Thomas W., and Clark, David L.

Subjects
Plutonium -- Research, Soil disinfection -- Research, Bacillus (Bacteria) -- Research, Metallic oxides -- Research, Bioremediation -- Research, Environmental issues, Science and technology
Abstract

The solubilization of hydrous plutonium hydrous oxide by iron-reducing bacteria strains is described. Plutonium removal from soils is a daunting task due to its strong absorption to soils and limited solubility. Microbial metal reduction was utilized for the solubilization and metal extraction from refractory ores. The research observations suggest the need to formulate an environmentally benign strategy for the remediation of plutonium-contaminated soils.

Published
1994

4. Investigation of the Structural Properties of an Extended Series of Lanthanide Bis-hydroxychlorides Ln(OH)2Cl (Ln = Nd−Lu, except Pm and Sm)

Author

Zehnder, Ralph A., Clark, David L., Scott, Brian L., Donohoe, Robert J., Palmer, Phillip D., Runde, Wolfgang H., and Hobart, David E.

Abstract

The trivalent lanthanide bis-hydroxychloride compounds, Ln(OH)2Cl, (Ln = Nd through Lu, with the exception of Pm and Sm) have been prepared by hydrothermal synthesis starting with LnCl3·nH2O. These compounds were synthesized at temperatures not exceeding the melting point of the Teflon liners in the Parr autoclaves (∼220 °C). The compounds obtained were characterized by single crystal X-ray diffraction analysis, diffuse reflectance, FT-IR, and FT-Raman spectroscopies. Most of the lanthanide(III) bis-hydroxychlorides are isostructural and generally crystallize in the monoclinic space group P21/m. The bis-hydroxychlorides of the heavier lanthanide(III) atoms with smaller ionic radii also crystallize in the orthorhombic crystal system. Apparently hydrogen bonds between the OH groups and the Cl atoms connect the layers in the “c” direction. These H-bonds seem to be the driving force for the angle β of the monoclinic complexes to decrease with decreasing ionic radius of the Ln(III) ion and also for tying the layers together more strongly. As a result of this behavior, the structure of the heavier 4f analogues significantly resembles that of their orthorhombic counterparts. The heavier lanthanide bis-hydroxychlorides preferentially crystallize in the orthorhombic modification. The IR absorbance and Raman frequencies of the hydroxide ligands correlate as a function of the central lanthanide(III) ionic radius. This observation is corroborated by X-ray diffraction (XRD) structural data. These compounds are quite insoluble in near-neutral and basic aqueous solutions, but soluble in acidic solutions. It is expected that the analogue actinide bis-hydroxychlorides exhibit similar behavior and that this may have important implications in the immobilization and safe disposal of nuclear waste.

Published
2024
Full Text
View/download PDF

5. Investigation of the structural properties of an extended series of lanthanide bis-hydroxychlorides Ln[(OH).sub.2]Cl (Ln = Nd-Lu, except Pm and Sm)

Author

Zehnder, Ralph A., Clark, David L., Scott, Brian L., Donohoe, Robert J., Palmer, Phillip D., Runde, Wolfgang H., and Hobart, David E.

Subjects
Chlorides -- Chemical properties, Dichloropropane -- Chemical properties, Fourier transform infrared spectroscopy -- Usage, Hydrogen bonding -- Analysis, Rare earth metals -- Chemical properties, X-rays -- Diffraction, X-rays -- Usage, Chemistry
Published
2010

6. XAFS structural determination of Np(VII). Evidence for a trans dioxo cation under alkaline solution conditions

Author

Clark, David L., Conradson, Steven D., Neu, Mary P., Palmer, Phillip D., Runde, Wolfgang, and Tait, C. Drew

Subjects
Molecular structure -- Research, Solution (Chemistry) -- Research, Ions -- Research, Chemistry
Abstract

A study was conducted to determine the XAFS structure of Np(VII) under alkaline solution conditions. The findings indicate the presence of a trans dioxo ion in the Np(VII) species in alkaline solution. The presence of trans dioxo ions was observed in the amplitudes of the isolated EXAFS of the oxo shells. Several studies to determine the solid-state structure, number of equatorial ligands and solution dynamics are ongoing.

Published
1997

7. EXAFS studies of pentavalent neptunium carbonato complexes. Structural elucidation of the principal constituents of neptunium in groundwater environments

Author

Clark, David L., Conradson, Steven D., Ekberg, Scott A., Hess, Nancy J., Neu, Mary P., Palmer, Phillip D., Runde, Wolfgang, and Tait, C. Drew

Subjects
Extended X-ray absorption fine structure -- Evaluation, Actinide elements -- Research, Chemistry
Abstract

The actinide element neptunium (Np) presents a potent threat against the environment because it is highly soluble under typical groundwater conditions and has low sorption on common minerals. Carbonato complexes of pentavalent neptunium play a significant role in the transport of Np in natural aquatic environments. The molecular structures of pentavalent neptunium compounds are investigated.

Published
1996

16. Higher Order Speciation Effects on Plutonium L3 X-ray Absorption Near Edge Spectra

Author

Conradson, Steven D., primary, Abney, Kent D., additional, Begg, Bruce D., additional, Brady, Erik D., additional, Clark, David L., additional, den Auwer, Christophe, additional, Ding, Mei, additional, Dorhout, Peter K., additional, Espinosa-Faller, Francisco J., additional, Gordon, Pamela L., additional, Haire, Richard G., additional, Hess, Nancy J., additional, Hess, Ryan F., additional, Keogh, D. Webster, additional, Lander, Gerard H., additional, Lupinetti, Anthony J., additional, Morales, Luis A., additional, Neu, Mary P., additional, Palmer, Phillip D., additional, Paviet-Hartmann, Patricia, additional, Reilly, Sean D., additional, Runde, Wolfgang H., additional, Tait, C. Drew, additional, Veirs, D. Kirk, additional, and Wastin, Franck, additional

Published
2003
Full Text
View/download PDF

17. Chemical speciation of the uranyl ion under highly alkaline conditions. Synthesis, structures, and oxo ligand exchange dynamics

Author

Clark, David L., Conradson, Steven D., Donohoe, Robert J., Keogh, D. Webster, Morris, David E., Palmer, Phillip D., Rogers, Robin D., and Tait, C. Drew

Subjects
Oxo compounds -- Research, Ligands -- Research, Hydrolysis -- Research, Hydroxides -- Research, Chemistry
Abstract

Research was conducted to examine the chemical speciation of the uranyl ion under highly alkaline conditions. Tetramethylammonium countercation was used to prevent the precipitation of uranate salts which allowed for the study of uranyl hydroxide complexes under highly alkaline solution conditions. Results indicate that an equilibrium exists between two species, assigned to UO2(OH)(sub 4)(super 2-) and UO2(OH)(sub 5)(super 3-).

Published
1999

24. Higher Order Speciation Effects on Plutonium L[sub 3] X-ray Absorption Near Edge Spectra.

Author

Conradson, Steven D., Abney, Kent D., Begg, Bruce D., Brady, Erik D., Clark, David L., den Auwer, Christophe, Mei Ding, Christophe, Dorhout, Peter K., Espinosa-Faller, Francisco J., Gordon, Pamela L., Haire, Richard G., Hess, Nancy J., Hess, Ryan F., Keogh, D. Webster, Lander, Gerard H., Lupinetti, Anthony J., Morales, Luis A., Neu, Mary P., and Palmer, Phillip D.

Published
2004
Full Text
View/download PDF

27. Higher order speciation effects on plutonium L(3) X-ray absorption near edge spectra.

Author

Conradson SD, Abney KD, Begg BD, Brady ED, Clark DL, den Auwer C, Ding M, Dorhout PK, Espinosa-Faller FJ, Gordon PL, Haire RG, Hess NJ, Hess RF, Keogh DW, Lander GH, Lupinetti AJ, Morales LA, Neu MP, Palmer PD, Paviet-Hartmann P, Reilly SD, Runde WH, Tait CD, Veirs DK, and Wastin F

Abstract

Pu L(3) X-ray near edge absorption spectra for Pu(0-VII) are reported for more than 60 chalcogenides, chlorides, hydrates, hydroxides, nitrates, carbonates, oxy-hydroxides, and other compounds both as solids and in solution, and substituted in zirconolite, perovskite, and borosilicate glass. This large database extends the known correlations between the energy and shape of these spectra from the usual association of the XANES with valence and site symmetry to higher order chemical effects. Because of the large number of compounds of these different types, a number of novel and unexpected behaviors are observed, such as effects resulting from the medium and disorder that can be as large as those from valence.

Published
2004
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results