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Articles 5611 - 5640 of 7341

Full-Text Articles in Physical Sciences and Mathematics

Sondrestrom Overview, Vincent B. Wickwar, J D. Kelly, O De La Beaujardiere, C A. Leger, F Steenstrup, C H. Dawson Jan 1984

Sondrestrom Overview, Vincent B. Wickwar, J D. Kelly, O De La Beaujardiere, C A. Leger, F Steenstrup, C H. Dawson

All Physics Faculty Publications

This overview of the Sondrestrom radar provides background material to help understand the early scientific results discussed in the following series of papers. It describes the geophysical region probed by the radar, the data acquisition procedure, and the extensive set of physical parameters derived.

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The Polar Ionosphere: Editorial, Vincent B. Wickwar, J W. Meriwether Jr. Jan 1984

The Polar Ionosphere: Editorial, Vincent B. Wickwar, J W. Meriwether Jr.

All Physics Faculty Publications

Editorial

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Initial Millstone Hill, Sondrestrom, And Hilat Observations Of Thermospheric Temperatures And Frictional Heating, W L. Oliver, J C. Foster, J M. Holt, G B. Loriot, Vincent B. Wickwar, J D. Kelly, O De La Beaujardiere, P F. Bythrow, D I. Meng, F J. Rich, R E. Huffman Jan 1984

Initial Millstone Hill, Sondrestrom, And Hilat Observations Of Thermospheric Temperatures And Frictional Heating, W L. Oliver, J C. Foster, J M. Holt, G B. Loriot, Vincent B. Wickwar, J D. Kelly, O De La Beaujardiere, P F. Bythrow, D I. Meng, F J. Rich, R E. Huffman

All Physics Faculty Publications

Elevation scan observations made by the Millstone Hill and Sondrestrom incoherent scatter radars are combined to provide extended latitudinal coverage of thermospheric measurements. Maps of the latitudinal and temporal structure of the exospheric temperature are presented for two 24‐hour periods over the latitude range 45 to 72 degrees north. On the magnetically quiet June day the Millstone and Sondrestrom data formed a consistent picture of thermospheric structure. On the disturbed July day the two radars observed very different behavior, with Millstone Hill observing strong, long‐lived ion frictional heating events but Sondrestrom observing more quiescent behavior. Comparison with HILAT satellite data …

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Plasma Characteristics Of Polar Cap F-Layer Arcs, H C. Carlson Jr., Vincent B. Wickwar, E J. Weber, J Buchau, J G. Moore, W Whiting Jan 1984

Plasma Characteristics Of Polar Cap F-Layer Arcs, H C. Carlson Jr., Vincent B. Wickwar, E J. Weber, J Buchau, J G. Moore, W Whiting

All Physics Faculty Publications

First results are reported of a comprehensive campaign to measure ionospheric structure and dynamics of nighttime polar cap F‐layer or F‐region arcs. Airborne optical and digital ionosonde data were collected simultaneously with ground based incoherent scatter radar data, continuously over many hours in time and 500 to 1000 km in space. Polar cap F‐region sub‐visual auroral arcs, which are commonly observed during quiet magnetic conditions, are found to represent boundaries (or shears) in the polar cap plasma circulation pattern. F‐region electron concentration enhancements are found in these features and can be of significance to polar thermospheric circulation, composition, and thermal …

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The Meridional Thermospheric Neutral Wind Measured By Radar And Optical Techniques In The Auroral Region, Vincent B. Wickwar, J W. Meriwether Jr., P B. Hays, A F. Nagy Jan 1984

The Meridional Thermospheric Neutral Wind Measured By Radar And Optical Techniques In The Auroral Region, Vincent B. Wickwar, J W. Meriwether Jr., P B. Hays, A F. Nagy

All Physics Faculty Publications

Radar observations of ion velocities in the magnetic zenith over Chatanika, Alaska, were used to determine the geomagnetic meridional component of the thermospheric neutral wind. Corrections for molecular diffusion and molecular ion contamination of the pure O+ composition assumed for the ionosphere were included in the analysis. Comparison of the averaged diurnal variation of the meridional wind showed good agreement between the two measurement techniques. Good agreement was also found for several cases of simultaneous observations. The evidence suggested that differences were caused by gravity waves. The 7 years of radar meridional wind results were examined with respect to …

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Pitch Angle Properties Of Magnetospheric Thermal Protons And Satellite Sheath Interference In Their Observation, Jan Josef Sojka, G. L. Wrenn, J.F. E. Johnson Jan 1984

Pitch Angle Properties Of Magnetospheric Thermal Protons And Satellite Sheath Interference In Their Observation, Jan Josef Sojka, G. L. Wrenn, J.F. E. Johnson

All Physics Faculty Publications

Cold proton observations from the geosynchronous GEOS 2 satellite are presented to show the pitch angle distribution of the refilling cold ion population found beyond the plasmapause. This refilling cold ion population flows into the depleted equatorial regions of the flux tubes from the topside ionosphere. This refilling is observed both day and night. The ions have energies between 0.5 and 3 eV. These energy characteristics are consistent with other recent observations. Although the observed angular distribution of these ions is highly complex, when allowance is made for the satellite sheath several conclusions can be made concerning the ion pitch …

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Nighttime Thermospheric Winds Over Sondre Stromfjord, Greenland, J W. Meriwether Jr., P Shih, T L. Killeen, Vincent B. Wickwar, R G. Roble Jan 1984

Nighttime Thermospheric Winds Over Sondre Stromfjord, Greenland, J W. Meriwether Jr., P Shih, T L. Killeen, Vincent B. Wickwar, R G. Roble

All Physics Faculty Publications

Observations of nighttime thermospheric neutral winds made at Sondre Stromfjord, Greenland, with optical and radar instrumentation, showed an occasional abatement in the equatorward meridional wind at a magnetic local time corresponding to the nighttime division between the evening and morning convection cells. This abatement appeared primarily in the poleward observations. In contrast, however, the characteristic midnight “surge” was usually seen in the equatorward set of observations. The apparent acceleration of about 250 m/s or greater within 4.6° latitude we attribute, in part, to a merging of neutral jet streams generated by polar cap ion drag adjacent to the auroral zone …

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Trihalomethane Compounds And Their Precursors In Salt Lake County: Evaluation Of Trihalomethane Source And Production, Kyle R. Cook, V. Dean Adams, Dennis B. George, Vincent A. Lamarra, Richard A. Hanson Jan 1984

Trihalomethane Compounds And Their Precursors In Salt Lake County: Evaluation Of Trihalomethane Source And Production, Kyle R. Cook, V. Dean Adams, Dennis B. George, Vincent A. Lamarra, Richard A. Hanson

Reports

Salt Lake County, Utah, watershed streams, drinking water treatment plants, and distribution systems were monitored for a period of one year or greater to determine the seasonal watershed precursor load, trihalomethane (THM) formation, and correlation between the two in the drinking water supplies. In addition, unit treatment processes were examined at Parleys, Big and Little Cottonwood water treatment plants, in the spring and late summer, to evaluate THM precursor reduction and THM formation. Additional studies were also conducted to appraise the potential contribution of natural sources to watershed THM precursor loading. Total organic carbon was used to estimate THM precursor …

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A Groundwater Model Of Cache Valley, Utah, Calvin G. Clyde, Roland W. Jeppson, Win-Kai Liu Jan 1984

A Groundwater Model Of Cache Valley, Utah, Calvin G. Clyde, Roland W. Jeppson, Win-Kai Liu

Reports

This report describes the development, calibration and use of quantitative, predictive management model for the groundwater in the Utah portion of the Cache Valley in northern Utah. The quasi-three-dimensional finite difference computer model was adapted from the U.S. Geological Survey’s Trescott and Larson model and simulates the groundwater levels and flows in the groundwater basin. The variable spacing grid system is 23 nodes x 38 x 2 and represents the complex natural system by a simpler approximation with one unconfined and one confined aquifer and the appropriate boundary and initial conditions. River nodes, spring nodes, and constant head nodes were …

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Use Of The Hewlett-Packard 9810 Calculator System In Water Quality Analysis, Jerald S. Fifield Jan 1984

Use Of The Hewlett-Packard 9810 Calculator System In Water Quality Analysis, Jerald S. Fifield

Reports

Introduction: It is the purpose of this manual to illustrate the utilization of the Hewlett-Packard, Model 9810A calculator for analyzing water quality data. Familiarization of each program's capabilities is essential for successful application, thus the user should read over the section used before beginning. Each section is complete with instructions and illustrative examples.

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Direct Filtration Versus Conventional Water Treatment In The Intermountain Region, Susan K. Burns, V. Dean Adams, Steel B. Maloney Jan 1984

Direct Filtration Versus Conventional Water Treatment In The Intermountain Region, Susan K. Burns, V. Dean Adams, Steel B. Maloney

Reports

The direct filtration water treatment scheme does not include sedimentation and in some cases flocculation. Compared to conventional treatment, direct filtration has lowered capital costs, reduced space requirements, decreased sludge quantities, and reduced coagulant dosages. One objective of this research was the statistical comparison of the direct filtration, Utah Valley Water Purification Plant (Orem, Utah) and the conventional Little Cottonwood Water Treatment Plant (Salt Lake City, Utah). These treatment plants are the two most compatible treatment plants having the highest correlation of source water in the local area. The Little Cottonwood plant receives approximately 65 percent of its sources water …

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Sediment-Phosphorus Relationships In Deer Creek Reservoir, Jay J. Messer, Thomas B. Hardy, Jean M. Ihnat Jan 1984

Sediment-Phosphorus Relationships In Deer Creek Reservoir, Jay J. Messer, Thomas B. Hardy, Jean M. Ihnat

Reports

Summary and Conclusions: Laboratory analyses of sediment samples recovered from Deer Creek Reservoir showed the sediments to have amoderate potential for serving as a source of phosphorus (P) for the overlying water solumn under anaerobic conditions. This source could account for the occurrence or exacerbation of blue-green algal blooms in the upper end of the reservoir when the sediment surface becomes anaerobic late in the summer. It could also delay the response of the reservoir to programs that decrease external P loading, if the upper end of the reservoir still has large enough algal blooms to render the sediment-water interface …

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Review Of In-Place Treatment Techniques For Contaminated Surface Soils - Volume 2: Background Information For In Situ Treatment, Ronald C. Sims, Darwin L. Sorensen, Judith Sims, Joan E. Mclean, Ramzi Mahmood, R. Ryan Dupont Jan 1984

Review Of In-Place Treatment Techniques For Contaminated Surface Soils - Volume 2: Background Information For In Situ Treatment, Ronald C. Sims, Darwin L. Sorensen, Judith Sims, Joan E. Mclean, Ramzi Mahmood, R. Ryan Dupont

Reports

This second volume of a two volume manual on in-place treatment of hazardous waste contaminated soil supports the treatment methodology described in Volume 1 (EPA- ). The information presented on monitoring to determine treatment effectiveness, characterization and evaluation of the behavior and fate of hazardous constituents in soil/waste systems, and properties (including adsorption, degradation, and volatilization parameters) for various compounds is intended to help the manual user in making more complex decisions and in selecting analyses concerning site, soil, and waste interactions. This report was submitted in partial fulfillment of Contract No. 68-03-3113 by Utah State University under the sponsorship …

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Crop-Tree Thinning A 50-Year-Old Western Larch Stand: 25-Year Results, United States Department Of Agriculture, Forest Service Jan 1984

Crop-Tree Thinning A 50-Year-Old Western Larch Stand: 25-Year Results, United States Department Of Agriculture, Forest Service

Forestry

This paper describes study results after 25 years of crop-tree thinning in a western larch (Larix occidentalis Nutt.) pole stand in western Montana. Five 1/2-acre plots were established in the Petty Creek drainage, Lolo National Forest, at an elevation of 4,200 feet above sea level. Western larch site index of the study area was 52 feet at 50 years. The stand was 50 years old when the study began in 1949. Two plots were thinned by the D+4 Rule, two by the Crown Rule, and one was left unthinned as a control. After 25 years, periodic diameter, basal area, and …

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Field Tests Of Elk/Timber Coordination Guidelines, United States Department Of Agriculture, Forest Service Jan 1984

Field Tests Of Elk/Timber Coordination Guidelines, United States Department Of Agriculture, Forest Service

Forestry

During the summers of 1980 and 1981, field validation tests were conducted in 11 different areas in Montana and northern Idaho. The objectives of this research were (1) to evaluate several common methods of determining cover/forage ratios, (2) to evaluate several different road-influence models, and (3) to determine the combination of cover/forage function and road model that best describes actual elk selection among different available habitats.

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Effect Of Small Aspen Clearcuts On Water Yield And Water Quality, United States Department Of Agriculture, Forest Service Jan 1984

Effect Of Small Aspen Clearcuts On Water Yield And Water Quality, United States Department Of Agriculture, Forest Service

Forestry

Streamflow and water quality were monitored in a paired watershed study involving the removal of 20 percent of the aspen (on 13 percent of the area) in five small clearcuts from a 217-acre (88-ha) catchment. There were no significant changes in peak flow, timing, or annual yield during the 4 years of posttreatment monitoring. Significant changes in pH, calcium, magnesium, and nitrates in the snowmelt streamflow from ephemeral subdrainages occurred the second year after cutting. At least some of the differences were attributed to the chemistry of the 1976-77 snowfall, which was also significantly different from snow sampled in the …

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The Sleeping Child Burn - 21 Years Of Postfire Change, United States Department Of Agriculture, Forest Service Jan 1984

The Sleeping Child Burn - 21 Years Of Postfire Change, United States Department Of Agriculture, Forest Service

Forestry

In early August 1961, more than 26,000 acres (10,500 ha) of upper montane and subalpine forest on the Bitterroot National Forest burned in a lightning-caused wildfire. At the time, the Sleeping Child Burn represented the single largest forest fire in the Northern Rocky Mountains in more than 20 years. Historically, large wildfires have not been uncommon in this region: but after two decades of successful forest fire suppression, the Sleeping Child was treated as an event almost without precedent. Not only was reseeding and rehabilitation an immediate concern, a substantial effort was invested in attempting to return the burned area …

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Tree Diameter Measurements At English And Metric Standard Heights: A Comparison, United States Department Of Agriculture, Forest Service Jan 1984

Tree Diameter Measurements At English And Metric Standard Heights: A Comparison, United States Department Of Agriculture, Forest Service

Forestry

The impact of measuring trees at 1.3 m versus 1.37 m heights above ground line was analyzed. The results indicate that the difference in diameter measurement taken at the two points averages around 1 percent. An equation for converting from English diameter at breast height to the metric equivalent of 1.3 m is presented.

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Development Of Structured Regression Hypotheses Interactive/Descriptive Geometry Through Five Dimensions, United States Department Of Agriculture, Forest Service Jan 1984

Development Of Structured Regression Hypotheses Interactive/Descriptive Geometry Through Five Dimensions, United States Department Of Agriculture, Forest Service

Miscellaney

Regression hypotheses admitted to statistical evaluation should, of course, be germain to relations between the variables considered. This constraint is easily violated with the screening of arbitrarily adopted sets of hypotheses. Sequential polynomials in additive models, for example, may include components that are not commensurate with expectation (prior knowledge) and may not include those that are (e.g., unique interaction terms) and, since the analytical results from the screening of meaningless hypotheses may themselves be meaningless, there is substantial incentive for serious preanalysis consideration of the hypotheses to be evaluated.

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Flood Insurance Study, City Of Logan, Utah, Cache County, Federal Emergency Management Agency Jan 1984

Flood Insurance Study, City Of Logan, Utah, Cache County, Federal Emergency Management Agency

All U.S. Government Documents (Utah Regional Depository)

This Flood Insurance Study investigates the existence and severity of flood hazards in the City of Logan, Cache County, Utah, and aids in the administration of the National Flood Insurance act of 1968 and the Flood Disaster Protection Act of 1973. This study will be used to convert Logan to the regular program of flood insurance by the Federal Emergency Management Agency (FEMA). Local and regional planners will use this study in their efforts to promote sound flood plain management.

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Studies Of Dispersion Energy In Hydrogen‐Bonded Systems. H2o–Hoh, H2o–Hf, H3n–Hf, Hf–Hf, M. M. Szczesniak, Steve Scheiner Jan 1984

Studies Of Dispersion Energy In Hydrogen‐Bonded Systems. H2o–Hoh, H2o–Hf, H3n–Hf, Hf–Hf, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Dispersion energy is calculated in the systems H2O–HOH, H2O–HF, H3N–HF, and HF–HF as a function of the intermolecular separation using a variety of methods. M≂ller–Plesset perturbation theory to second and third orders is applied in conjunction with polarized basis sets of 6‐311G∗∗ type and with an extended basis set including a second set of polarization functions (DZ+2P). These results are compared to a multipole expansion of the dispersion energy, based on the Unsöld approximation, carried out to the inverse tenth power of the intermolecular distance. Pairwise evaluation is also carried out using both atom–atom …

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Proton Transfers Between First‐ And Second‐Row Atoms: (H2ohsh2)+ And (H3nhsh2)+, Steve Scheiner Jan 1984

Proton Transfers Between First‐ And Second‐Row Atoms: (H2ohsh2)+ And (H3nhsh2)+, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Ab initio molecular orbital methods are used to study the transfer of the central proton along the hydrogen bonds in (H2OHSH2)+ and (H3NHSH2)+. Proton transfer potentials are generated using the 4‐31G∗ basis set at the Hartree–Fock level for various values for the hydrogen bond length R(XS). Full geometry optimizations are carried out at each stage of proton transfer. The barrier to proton transfer increases as the hydrogen bond is lengthened. For a given bond length, the highest barriers are observed for transfer from …

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Ab Initio Comparison Of H Bonds And Li Bonds. Complexes Of Lif, Licl, Hf, And Hcl With Nh3, Z. Latajka, Steve Scheiner Jan 1984

Ab Initio Comparison Of H Bonds And Li Bonds. Complexes Of Lif, Licl, Hf, And Hcl With Nh3, Z. Latajka, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Ab initio calculations are carried out on the complexes H3N–LiF, H3N–LiCl and their analogs H3N–HF and H3N–HCl as well as the isolated subunits. Double‐zeta basis sets, augmented by two sets of polarization functions, are used in conjunction with second‐order Moller–Plesset perturbation theory (MP2) for evaluation of electron correlation effects. The Li bonds are found to be substantially stronger than their H‐bonding counterparts, due in large measure to the greater dipole moments of the LiX subunits. Correlation has a large effect on the geometry and energetics of …

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Natural Variational Principles On Riemannian Structures, Ian M. Anderson Jan 1984

Natural Variational Principles On Riemannian Structures, Ian M. Anderson

Ian M. Anderson

No abstract provided.

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Electric Field And Plasma Density Measurements In The Auroral Electrojet, R. Pfaff, M. C. Kelley, Bela G. Fejer, E. Kudeki, C. W. Carlson, A. Pedersen, B. Hausler Jan 1984

Electric Field And Plasma Density Measurements In The Auroral Electrojet, R. Pfaff, M. C. Kelley, Bela G. Fejer, E. Kudeki, C. W. Carlson, A. Pedersen, B. Hausler

Bela G. Fejer

Intense electrostatic waves in the auroral E region have been detected simultaneously on two payloads launched in a mother-daughter configuration from Kiruna, Sweden. The data sets comprise electric field and density measurements from the ambient (dc) conditions to fluctuations as high as 50 kHz. The dc electric field measured by both payloads was 54 mV/m northwest, which corresponded to an electron drift velocity of 1080 m/s. This electric field drove two-stream waves perpendicular to both B and E observed by both spacecraft throughout an altitude region which agrees quite well with the range predicted by linear two-stream theory. The power …

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Ion Cyclotron Waves As Apossible Source Of Resonant Auroral Radar Echoes, Bela G. Fejer, R. W. Reed, D. T. Farley, W. E. Swartz, M. C. Kelley Jan 1984

Ion Cyclotron Waves As Apossible Source Of Resonant Auroral Radar Echoes, Bela G. Fejer, R. W. Reed, D. T. Farley, W. E. Swartz, M. C. Kelley

Bela G. Fejer

Auroral backscatter radar observations were made from Ithaca, New York, at 50 MHz during the early morning of April 1, 1976, a period of high magnetic disturbance (Kp ∼ 8). The backscattered power showed large rapid (time scale of a few minutes or less) variations, characteristic of discrete radar aurora, from L = 3.5–4. Doppler spectra of waves propagating in nearly the north-south direction from up to 28 different ranges were obtained simultaneously with good spatial (7.5 km) and temporal (2 s) resolution. Some unusual spectra with very narrow peaks at Doppler shifts between about 70 and 90 Hz were …

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Directional And Dynamic Variations Ofauroral Power Spectra Related To The Ionospheric Electron Drift Velocity, E. Nielsen, C. I. Haldoupis, Bela G. Fejer, H. M. Ierkic Jan 1984

Directional And Dynamic Variations Ofauroral Power Spectra Related To The Ionospheric Electron Drift Velocity, E. Nielsen, C. I. Haldoupis, Bela G. Fejer, H. M. Ierkic

Bela G. Fejer

Power spectral observations of auroral electron density fluctuations with a scale length of nearly 1 m have been made with the STARE system (Scandinavian twin auroral radar experiment). Simultaneous measurements of the mean radial Doppler velocities were used to derive estimates of the ionospheric electron drift velocity. The data were analyzed to determine the spectral dependence on the magnitude and direction of the electron drift velocity. The two spectral types, characterized as “narrow” and “broad,” were observed simultaneously from the same scattering volume. The width of the broad spectrum (up to about 1200 Hz) can be at least 3 times …

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Theory Of Plasma Waves In The Auroral E-Region, Bela G. Fejer, J. Providakes, D. T. Farley Jan 1984

Theory Of Plasma Waves In The Auroral E-Region, Bela G. Fejer, J. Providakes, D. T. Farley

Bela G. Fejer

We have extended the linear fluid theory of electrojet plasma waves to the region where ion magnetization effects are important. Our general dispersion relation includes the effect of cross-field and field-aligned drifts, ion inertia, electron density gradients, and recombination. In the absence of density gradients and recombinational damping, the oscillation frequency at marginal instability is changed by the ion magnetization effects from the ion acoustic frequency, ω = kCs, to the modified ion cyclotron frequency ω² = Ωi² + k²Cs². These upper E region waves can be driven by field-aligned and/or cross-field drifts and have the smallest threshold drift velocities …

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Prehistory Of Long Valley, Idaho, United States Department Of Agriculture, Forest Service Jan 1984

Prehistory Of Long Valley, Idaho, United States Department Of Agriculture, Forest Service

Archaeology/Anthropology

This thesis deals with a group of artifact collections gathered by local amateurs from a series of sites along the western shoreline of Cascade Reservoir. This study uses these artifacts as a basis to put together a preliminary view of Long Valley prehistory. Outlines of the basic artifact types are formulated and placed into a chronology based upon typological comparisons and obsidian hydration. Previous archaeological work, the ethnohistory, and local geology of the valley are discussed and related ot the sites, used in this study, in order to determine their patterns and characteristics. From these efforts directions for further research …

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Theoretical Study Of H2o–Hf And H2o–Hcl: Comparison With Experiment, M. M. Szczesniak, Steve Scheiner, Y. Bouteiller Jan 1984

Theoretical Study Of H2o–Hf And H2o–Hcl: Comparison With Experiment, M. M. Szczesniak, Steve Scheiner, Y. Bouteiller

Chemistry and Biochemistry Faculty Publications

The H bonds in H2O–HF and H2O–HCl are studied and compared using ab initio molecular orbital methods and the results compared to experimental data. Basis sets used are: (i) triple valence 6‐311G∗∗ and (ii) double ζ with two sets of polarization functions. Electron correlation, included via second‐ and third‐order Møller–Plesset perturbation theory, is found to have profound effects on both systems, particularly H2O–HCl. Both H bonds are strengthened substantially with a concomitant reduction in length. H‐bond energies and geometries calculated at correlated levels are in excellent accord with …

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