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Full-Text Articles in Earth Sciences
Average Steady Nonuniform Flow In Stratified Formations, Peter Indelman, Vitaly A. Zlotnik
Average Steady Nonuniform Flow In Stratified Formations, Peter Indelman, Vitaly A. Zlotnik
Department of Earth and Atmospheric Sciences: Faculty Publications
A mathematical model of average nonuniform flow in heterogeneous stratified media is developed. The averaged Darcy's law is obtained by deriving the analytical expression of the effective conductivity tensor for media with small heterogeneities. The fundamental solution of the average flow equation (mean Green function) corresponding to the flow toward a single point source of deterministic discharge is derived. The mean head distribution is calculated for a fully penetrating well, for a finite length well in an infinite domain, and for a dipole well. The concept of equivalent conductivity is defined for use in identifying the formation conductivity properties. The …
Effect Of Sulfate On The Release Rate Of Al3+ From Gibbsite In Low-Temperature Acidic Waters, Moira K. Ridley, David J. Wesolowski, Donald A. Palmer, Pascale Bénézeth, Richard Kettler
Effect Of Sulfate On The Release Rate Of Al3+ From Gibbsite In Low-Temperature Acidic Waters, Moira K. Ridley, David J. Wesolowski, Donald A. Palmer, Pascale Bénézeth, Richard Kettler
Department of Earth and Atmospheric Sciences: Faculty Publications
Solubility experiments were performed at 5 °C by reacting 1 g of powdered gibbsite with 45 g of aqueous H2SO4-NaCl and HCl-NaCl (0.01 m H+) solutions at 0.1 m ionic strength. The kinetics of dissolution were monitored under extremely undersaturated conditions and appeared to favor a zero-order rate-determining process. The dissolution rate of gibbsite in the sulfate solution was approximately 10 times faster than in the HCl solution, which is consistent with trends reported in the literature for studies performed at higher temperatures. The enhanced dissolution kinetics of gibbsite (and by analogy, other aluminum-containing minerals) in …
Ground Water, Robert F. Diffendal Jr.
Ground Water, Robert F. Diffendal Jr.
Department of Earth and Atmospheric Sciences: Faculty Publications
A geologic overview of the groundwater supply underlying Cheyenne County, Nebraska (1997).
Geology, Robert F. Diffendal Jr.
Geology, Robert F. Diffendal Jr.
Department of Earth and Atmospheric Sciences: Faculty Publications
An overview of the geology of Cheyenne County, Nebraska.
Relations Between Directional Spectral Vegetation Indices And Leaf Area And Absorbed Radiation In Alfalfa, Elizabeth Walter-Shea, Jeffrey L. Privette, D. Cornell, Mark A. Mesarch, C. Hays
Relations Between Directional Spectral Vegetation Indices And Leaf Area And Absorbed Radiation In Alfalfa, Elizabeth Walter-Shea, Jeffrey L. Privette, D. Cornell, Mark A. Mesarch, C. Hays
Department of Earth and Atmospheric Sciences: Faculty Publications
s ensors on satellite platforms with extreme view angles have been increasingly used to analyze regional and global vegetation cover and productivity because of frequent observations. This study, using experimental and theoretical methods, analyzed variations in vegetation indices with sun-view geometry as a means of understanding the sensitivity of relations beween vegetation indices and the biophysical properties, the leaf area index (LAI), and the instantaneous fraction of absorbed photosynthetically active radiation (fAPAR). Canopy bidirectional reflectance factors (BRFs) of an alfalfa crop were measured and simulated at a variety of solar and view zenith angles. Also, fAPAR, LAI, and leaf optical …
Surface Textural Analysis Of Quartz Sand Grains From Odp Site 918 Off The Southeast Coast Of Greenland Suggests Glaciation Of Southern Greenland At 11 Ma, P. E. Helland, Mary Anne Holmes
Surface Textural Analysis Of Quartz Sand Grains From Odp Site 918 Off The Southeast Coast Of Greenland Suggests Glaciation Of Southern Greenland At 11 Ma, P. E. Helland, Mary Anne Holmes
Department of Earth and Atmospheric Sciences: Faculty Publications
Shipboard analysis of the 1,183-m sedimentary section recovered at Site 918 in the Irminger Basin during Ocean Drilling Program Leg 152 revealed material of glacial origin (diamictons, ice-rafted debris (IRD) and dropstones) as deep as 543 m below sea floor (bsf). The sediment containing the deepest dropstone was biostratigraphically dated shipboard as approximately 7 Ma, pushing back the date for the onset of glaciation on southern Greenland by 5 Ma. Thin layers of fine sand were found as much as 60 m deeper in the core, raising the possibility of an even earlier date for glaciation. To determine the sedimentary …