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Articles 331 - 355 of 355
Full-Text Articles in Bioresource and Agricultural Engineering
Physiological Diversity And Distributions Of Heterotrophic Bacteria In Deep Cretaceous Sediments Of The Atlantic Coastal Plain, James K. Fredrickson, David L. Balkwill, John M. Zachara, Shu-Mei W. Li, Fred J. Brockman, Mary Simmons
Physiological Diversity And Distributions Of Heterotrophic Bacteria In Deep Cretaceous Sediments Of The Atlantic Coastal Plain, James K. Fredrickson, David L. Balkwill, John M. Zachara, Shu-Mei W. Li, Fred J. Brockman, Mary Simmons
United States Department of Energy: Publications
A series of 23 intact core segments was obtained from two distinct deep subsurface geological formations, the Middendorf and the Cape Fear formations, underlying the southeastern coastal plain of South Carolina. The Middendorf formation in this region consists of permeable, saturated, sandy sediments; the Cape Fear formation consists mainly of less permeable sediments. The core segments were separated by vertical distances ranging from several centimeters to 48 m. Aerobic chemoheterotrophic bacteria were enumerated on a dilute medium, and populations ranged from 3.1 to 6.4 log CFU g of sediment-1 in the Middendorf cores and from below detection to 4.3 …
Identification Of Solubility-Controlling Solid Phases In A Large Fly Ash Field Lysimeter, Jonathan S. Fruchter, Dhanpat Rai, John M. Zachara
Identification Of Solubility-Controlling Solid Phases In A Large Fly Ash Field Lysimeter, Jonathan S. Fruchter, Dhanpat Rai, John M. Zachara
United States Department of Energy: Publications
Samples of pore fluids and leachates were obtained from a large fly ash field lysimeter in central Pennsylvania. The fly ash in the lysimeter was usually only partially saturated, and only 0.3 pore volumes of water leached through the lysimeter during the 3-year study period. The samples were analyzed for major and trace inorganic anions and cations. The resulting analyses were modeled by using an equilibrium speciation/solubility code to test the hypothesis that the solubilities of at least some species in the fly ash leachate were controlled by solid phases. Potential solubility-controlling solids were identified for Al, Ba, Ca, Cr, …
Influence Of Mineral-Bound Humic Substances On The Sorption Of Hydrophobic Organic Compounds, Ellyn M. Murphy, John M. Zachara, Steven C. Smith
Influence Of Mineral-Bound Humic Substances On The Sorption Of Hydrophobic Organic Compounds, Ellyn M. Murphy, John M. Zachara, Steven C. Smith
United States Department of Energy: Publications
The sorption of three hydrophobic organic compounds (HOC) was investigated on hematite and kaolinite that had been coated with natural humic substances over a mass percent carbon range of 0.01-0.5%. Increasing quantities of sorbed humic substances increased the sorption of HOC. Anthracene, the most hydrophobic HOC, showed the greatest sorption enhancement, while the most aromatic coating, peat humic acid, was the strongest sorbent. Depending on the type of humic acid coating and the mineral substrate, the experimental Koc values were either higher or lower than those predicted by the Kow The sorptivity of a given humic acid for …
Stress-Induced Infrared Frequency Shifts In Polyethylene, G. A. Pfeffer, D. W. Noid
Stress-Induced Infrared Frequency Shifts In Polyethylene, G. A. Pfeffer, D. W. Noid
United States Department of Energy: Publications
The molecular dynamics technique is used to study the spectral response of a polyethylene chain in a crystal environment under a mechanical deformation. The MUSIC method, which was previously shown to accurately compute dispersion curves from the time-dependent structure factor, is used. A complete characterization of frequency shifts is presented for various lamellar thickness, temperatures, stress (or pressure), and mass defects.
Sorption Of Aminonapht Halene And Quinoline On Amorphous Silica, John M. Zachara, Calvin C. Alnsworth, Christina Cowan, Ronald Schmidt
Sorption Of Aminonapht Halene And Quinoline On Amorphous Silica, John M. Zachara, Calvin C. Alnsworth, Christina Cowan, Ronald Schmidt
United States Department of Energy: Publications
The adsorption of quinoline and aminonaphthalene was investigated from aqueous solution on amorphous silica SiO2. Amorphous SiO2 was not a strong adsorbent of these compounds and quinoline was adsorbed more strongly than aminonaphthalene. The adsorption of both compounds varied with pH. A maximum in adsorption occurred near their respective pKa's. Temperature effects were significant, suggesting enthalpy contributions in the range of H bonding. Both compounds appeared to adsorb via identical mechanisms that included H bonding and ion exchange. The greater basicity of quinoline combined with (1) the enhanced electron-donating properties of the heteroatom N and …
Review Of Radial Dose Measurement Technique And Data, Matesh N. Varma
Review Of Radial Dose Measurement Technique And Data, Matesh N. Varma
United States Department of Energy: Publications
Radial dose is the average energy deposited in a short length of cylindrical shell formed between radii r and r + dr, per unit mass. Here, r is the distance perpendicular to the trajectory of an incident charged particle. Radial dose profiles as a function of radial distance for charged particles have been used to interpret radiobiological data. This article reviews the technique for measuring radial dose distributions and the available data.
Energetic Electron Tracks And Dna Strand Breaks, A. Chatterjee, W. R. Holley
Energetic Electron Tracks And Dna Strand Breaks, A. Chatterjee, W. R. Holley
United States Department of Energy: Publications
A theoretical model with no adjustable parameters is presented to evaluate the strand break yields for incident electrons between 100 eV and 1 MeV. Indirect mechanisms as well as direct mechanisms are included for the production of strand breaks. The model includes the following features: (i) multiple scattering of low energy electrons; (ii) decay of hydroxyl radicals in an aqueous solution containing Tris buffer; (iii) Monte Carlo simulation of the motion of hydroxyl radicals for interaction with the DNA sites; and (iv) stochastic aspects of the direct ionization on the DNA sites and the use of oscillator strength of a …
The Katz Cell-Survival Model And Beams Of Heavy Charged Particles, Stanley B. Curtis
The Katz Cell-Survival Model And Beams Of Heavy Charged Particles, Stanley B. Curtis
United States Department of Energy: Publications
In this paper, we describe how the Katz cell-survival model has been used to predict survival along the central axis of the dose vs depth curve of beams of heavy charged particles. Unmodified beams with sharp Bragg peaks as well as ridge-filter-modulated beams with spread Bragg peaks have been studied. The analysis in terms of this model leads to the definition of two coefficients, "ion kill" and "gamma kill", which characterize the radiation quality of the beams. In this way, the relative importance of the primary lind secondary (fragmentation) contributions can be assessed easily.
Setting the model parameter m equal …
Physical Aspects Of Charged Particle Track Structure, R. H. Ritchie, R. N. Hamm, J. E. Turner, H. A. Wright, J. C. Ashley, G. J. Banks
Physical Aspects Of Charged Particle Track Structure, R. H. Ritchie, R. N. Hamm, J. E. Turner, H. A. Wright, J. C. Ashley, G. J. Banks
United States Department of Energy: Publications
A plasmon generated by a swift charged particle constitutes a coherent excitation about the particle track. We discuss the physics of the plasmon in condensed matter and its effects on electron transport in liquid water. Criteria for the existence of the plasmon III a given substance, Its characteristics when generated by a swift charged particle, its representation in impact parameter space, and its decay into localized excitations are described. We describe how plasmon excitation and decay are implemented in our Monte Carlo code, OREC, and how track structure calculations are affected by this mode.
Subsurface Transport Of Contaminants, John E. Mccarthy, John M. Zachara
Subsurface Transport Of Contaminants, John E. Mccarthy, John M. Zachara
United States Department of Energy: Publications
Contaminants originating from human activities have entered the subsurface environment through waste disposal practices, spills, and land application of chemicals. The establishment of effective disposal and isolation procedures for chemical wastes, the protection of public health, and the amelioration of subsurface contamination rely on the ability to predict the velocity at which contaminants move through the vadose (unsaturated) and saturated zones. However, attempts to describe and predict contaminant transport cannot succeed if major pathways and mechanisms for transport are not defined.
Most approaches to describing and predicting the movement of contaminants treat groundwater as a two-phase system in which contaminants …
Interactions Of Antiprotons With Atoms And Molecules, Mitio Inokuti
Interactions Of Antiprotons With Atoms And Molecules, Mitio Inokuti
United States Department of Energy: Publications
Antiproton beams of relatively low energies (below hundreds of MeV) have recently become available. The present article discusses the significance of those beams in the contexts of radiation physics and of atomic and molecular physics. Studies on individual collisions of antiprotons with atoms and molecules are valuable for a better understanding of collisions of protons or electrons, a subject with many applications. An antiproton is unique as' a stable, negative heavy particle without electronic structure, and it provides an excellent opportunity to study atomic collision theory. Comparison of the stopping powers of a material for an antiproton and a proton …
Computer Simulation Of The Melting Process In Linear Macromolecules, Donald W. Noid, George A. Pfeffer, Stephen Z. D. Cheng, Bernhard Wunderlich
Computer Simulation Of The Melting Process In Linear Macromolecules, Donald W. Noid, George A. Pfeffer, Stephen Z. D. Cheng, Bernhard Wunderlich
United States Department of Energy: Publications
Polymer crystal melting kinetics is simulated by using molecular dynamics. A simplified molecular model of polyethylene crystal melting consisting of one extended chain on a polyethylene-like crystal surface is presented. The simulation data indicate that the end-to-end distance (eed) of radius of gyration (rg) has a simple exponential dependence on time. The rate constants for eed and rg are found to be temperature and molecular length dependent. A more detailed analysis of polymer crystal melting will be described
In-Situ Stress Orientation And Magnritjde At The Fenton Geothermal Site, New Mexico, Determined From Wellbore Breakouts, Colleen A. Barton, Mark D. Zoback, Kerry L. Burns
In-Situ Stress Orientation And Magnritjde At The Fenton Geothermal Site, New Mexico, Determined From Wellbore Breakouts, Colleen A. Barton, Mark D. Zoback, Kerry L. Burns
United States Department of Energy: Publications
The acoustic borehole televiewer provides excellent data for the detection and measurement of stress-induced wellbore breakouts. Analog televiewer data from the Fenton Geothermal well EE-3 in New Mexico were digitized and interactivly processed for detection and analysis of azimuth and shape of stress-induced breakouts occurring in the well at depths of about 2.9 - 3.5 km. A statistical analysis of the measured breakout azimuths yields a well resolved orientation of least horizontal principal stress of 119 °, consistent with least principal stress data from the Rio Grande Rift. As the magnitude of the least horizontal compressive stress, Shmin, in …
Quinoline Sorption On Na-Montmorillonite: Contributions Of The Protonated And Neutral Species, Calvin C. Ainsworth, John M. Zachara, Ron L. Schmidt
Quinoline Sorption On Na-Montmorillonite: Contributions Of The Protonated And Neutral Species, Calvin C. Ainsworth, John M. Zachara, Ron L. Schmidt
United States Department of Energy: Publications
Dilute aqueous solutions of quinoline were contacted with Na-montmorillonite to elucidate the sorption process of the neutral and protonated species. Sorption occurs via a combination of ion exchange and molecular adsorption and yields S-type isotherms. Exchange between the quinolinium ion (QH+ and Na can be described by means of Vanselow selectivity coefficients and a thermodynamic exchange constant (Kex). Due to the apparent adsorption of the neutral species at high mole fractions (x) of the solid phase, the thermodynamic standard state was defined as 0.5 mole fraction. The selectivity at pH ~4.95 of the QH+ species over …
Sorption Of Binary Mixtures Of Aromatic Nitrogen Heterocyclic Compounds On Subsurface Materials, John M. Zachara, Calvin C. Ainsworth, Christina E. Cowan, Berta L. Thomas
Sorption Of Binary Mixtures Of Aromatic Nitrogen Heterocyclic Compounds On Subsurface Materials, John M. Zachara, Calvin C. Ainsworth, Christina E. Cowan, Berta L. Thomas
United States Department of Energy: Publications
Single and binary solute sorption of pyridine, quinoline, and acridine has been investigated on two low organic carbon subsurface materials with similar properties but different equilibrium pH when saturated with water. Single solute sorption for all compounds is higher in the acidic soil as compared to the basic soil, reflecting stronger sorption of the protonated organic cations. The protonated species exhibit high selectivity for the exchange complex at low aqueous concentration with selectivity increasing with ring number. Binary sorption experiments with quinoline/pyridine and quinoline/acridine demonstrate that competitive sorption occurs between compounds in the acidic subsoil where the protonated compound species …
Applications Of The Semiclassical Spectral Method To Nuclear, Atomic, Molecular, And Polymeric Dynamics, M. L. Koszykowski, G. A. Pfeffer, D. W. Noid
Applications Of The Semiclassical Spectral Method To Nuclear, Atomic, Molecular, And Polymeric Dynamics, M. L. Koszykowski, G. A. Pfeffer, D. W. Noid
United States Department of Energy: Publications
Nonlinear dynamics plays a dominant role in a variety of important problems in chemical physics. Examples are unimolecular reactions, infrared multiphoton decomposition of molecules, the pumping process of the gamma ray laser, dissociation of vibrationally excited state-selected van der Waals’s complexes, and many other chemical and atomic processes. The present article discusses recent theoretical studies on the quasi-periodic and chaotic dynamical aspects of vibrational-rotational states of atomic, nuclear, and molecular systems using the semiclassical spectral method (SSM). We note that the coordinates, momenta, and so on, are found using classical mechanics in the studies included in this review. Consequently, certain …
Chromate Adsorption On Amorphous Iron Oxyhydroxide In The Presence Of Major Groundwater Ions, John M. Zachara, Donald Girvln, Ronald Schmidt, C. Thomas Resch
Chromate Adsorption On Amorphous Iron Oxyhydroxide In The Presence Of Major Groundwater Ions, John M. Zachara, Donald Girvln, Ronald Schmidt, C. Thomas Resch
United States Department of Energy: Publications
Chromate adsorption on amorphous iron oxyhydroxide was investigated in dilute iron suspensions as a single solute and in solutions of increasing complexity containing CO2 (g), SO42-(aq), H4Si04(aq), and cations [K+, Mg2+, Ca2+(aq)]. In paired-solute systems (e.g., CrO42- =H2CO3*), anionic cosolutes markedly reduce CrO42- adsorption through a combination of competitive and electrostatic effects, but cations exert no appreciable influence. Additionally, H4Si04 exhibits a strong time-dependent effect: CrO42- adsorption is greatly decreased with increasing H4SiO4 …
Convection In The Oceanic Crust' Simulationo F Observationsf Rom Deep Sea Drilling Project Hole 504b, Costa Rica Rift, Colin F. Williams, T. N. Narasimhan, Roger N. Anderson, Mark D. Zoback, Keir Becker
Convection In The Oceanic Crust' Simulationo F Observationsf Rom Deep Sea Drilling Project Hole 504b, Costa Rica Rift, Colin F. Williams, T. N. Narasimhan, Roger N. Anderson, Mark D. Zoback, Keir Becker
United States Department of Energy: Publications
Three-dimensional modeling of convection in the oceanic crust at Deep Sea Drilling Project site 504B using an integral finite difference model reasonably duplicates underpressures, surface heat flow, downhole temperature profiles, and fluid drawdown rates observed by in situ measurements in the borehole. The major constraint to produce such good fits is the permeability versus depth function,a quantity which was actually measured in the borehole. Pronounced "underpressuring" (fluid pressures less than hydrostatic) occurs throughout the convection cell if and only if a tight, nearly impermeable cap rock (chert) exists over the cell. The computed flow rates of water from the ocean …
Quinoline Sorption To Subsurface Materials: Role Of Ph And Retention Of The Organic Cation, John M. Zachara, Calvin Alnsworth, Larry Felice, Charles Resch
Quinoline Sorption To Subsurface Materials: Role Of Ph And Retention Of The Organic Cation, John M. Zachara, Calvin Alnsworth, Larry Felice, Charles Resch
United States Department of Energy: Publications
The sorption of quinoline (pKa = 4.94) was investigated on low-organic-carbon subsurface materials that varied in pH. Sorption isotherms were measured from 10-7 to 10-4 M quinoline and were found to be nonlinear. The resulting Freundlich constants (KF), based on total aqueous quinoline concentration, were poorly correlated with subsoil properties, including organic carbon. Higher sorption in the acidic subsoils and favorable coefficents for regression of KF, normalized to cation-exchange capacity vs. the ionization fraction (Q), point to the importance of ion exchange of the protonated compound. When the subsoil pH …
An Inventory Of Geothermal Resources In Nebraska, William D. Gosnold, Duane A. Eversoll
An Inventory Of Geothermal Resources In Nebraska, William D. Gosnold, Duane A. Eversoll
United States Department of Energy: Publications
The goal of the State Coupled Resource Assessment Program is to identify and evaluate geothermal resources in the state, particularly low-temperature potential. Eight tasks were identified and documented in this report as follows:
TASK ONE: Bottom-hole Temperature Survey
TASK TWO: Heat Flow and Temperature Gradient Survey
TASK THREE: Data Translation studies
TASK FOUR: Gravity Data
TASK FIVE: Substate Regions
TASK SIX: Information Dissemination
Heat Flow and Temperature Gradient Survey
TASK SEVEN: State Geothermal Map
TASK EIGHT: Reports
The project had three major products; (1) a map "Geothermal Resources of Nebraska,” (2) a significant amount of thermal data collected and documented …
Seasat-Satellite Investigation Of The Structure Of Western Nebraska And Its Application To The Evaluation Of Geothermal Resources, John Stix
United States Department of Energy: Publications
Seasat synthetic aperture radar (SAR) satellite imagery was used to interpret the structural framework and, indirectly, the geothermal potential of an area in western Nebraska. Lineaments were mapped from the imagery and then compared to known structure. It was found that Seasat does record surface manifestations of subtle basement structures, particularly faults and joints. Furthermore, two areas with hot dry rock geothermal potential were delineated using Seasat and other data. It is stressed that more subsurface geology and geophysical data are needed before a final evaluation of the geothermal potential can be made. Seasat imagery is a useful reconnaissance exploration …
Crystal And Molecular Structures Of Organophosphorus Insecticides. 13. S-Isopropyl 0-Methyl 0-(3,5,6-Trichloro-2-Pyridyl) Phosphoramidothioate And Dimethoate, Rick L. Lapp, Robert A. Jacobson
Crystal And Molecular Structures Of Organophosphorus Insecticides. 13. S-Isopropyl 0-Methyl 0-(3,5,6-Trichloro-2-Pyridyl) Phosphoramidothioate And Dimethoate, Rick L. Lapp, Robert A. Jacobson
United States Department of Energy: Publications
The crystal and molecular structures of S-isopropyl O-methyl O-(3,5,6-trichloro-2-pyridyl) phosphoramidothioate, C9H12N2O2PSC13, and dimethoate [ O,O-dimethyl S-(N-methylcarbamoyl)methyl phosphorodithioate], C5HI2NO3PS2, have been determined by three-dimensional X-ray analysis. The former compound crystallizes in the triclinic space group P1 with a = 10.319 (5) Å, b = 10.730 (6) Å, c = 8.44 (4) Å, a = 99.01 (2)°, β = 114.02 (l)°, and y = 62.64 (1)° with Z = 2, and the latter compound crystallizes in the monoclinic space group P21 …
Propagule Dispersal Among Forest Islands In Southeastern South Dakota, J. Warren Ranney, W. Carter Johnson
Propagule Dispersal Among Forest Islands In Southeastern South Dakota, J. Warren Ranney, W. Carter Johnson
United States Department of Energy: Publications
The study of seed dispersal between the widely separated forest patches (forest islands) of the eastern Great Plains can contribute to understanding effects of deforestation in the more complex forest island landscapes of the eastern United States. In the East, there is growing concern that the dissection of regional forests and the creation of small forest islands surrounded by non-forest uses (e.g., agriculture) may be affecting plant species richness and developmental patterns of vegetation (Levenson 1976), as has already been noted in the tropics (Gomezpompa et al. 1972). Curtis (1956) showed that the presettlement forest area in a portion of …
Missouri River Hydrology (Streamflow And Temperature) – Sioux City, Iowa To Rulo, Nebraska, David L. Schreiber
Missouri River Hydrology (Streamflow And Temperature) – Sioux City, Iowa To Rulo, Nebraska, David L. Schreiber
United States Department of Energy: Publications
In any plan for the development of water and land resources, hydrology must be a basic consideration. Because of the Missouri River Basin's large size and the many associated variations in hydrologic characteristics, hydrology is of special significance.
The Missouri River drains an area of approximately 530,000 square miles, and it is the longest river in the United States (2,315 miles). The source of the Missouri River is the headwaters of the Red Rock River in Montana, and the mouth is at the Mississippi River near St. Louis, Missouri. Part or all of 10 states and 9,700 square miles in …
The Uranyl Nitrate-Water System Above 60°, W. L. Marshall, Jr., J. S. Gill, C. H. Secoy
The Uranyl Nitrate-Water System Above 60°, W. L. Marshall, Jr., J. S. Gill, C. H. Secoy
United States Department of Energy: Publications
Although there are some data in the literature for the solubility of uranyl nitrate in water, the discrepancy of these data indicated the necessity for a check on the measurements. We have measured the solubility from the incongruent melting point of the hexahydrate at about 60° to the melting point of the dihydrate at 184°. Our results show a lower solubility than that given in most of the earlier data and also indicate an incongruent melting point for the trihydrate rather than the congruent point inferred in some of the previous work. The system is thermally stable up to the …