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Articles 284341 - 284370 of 304054

Full-Text Articles in Physical Sciences and Mathematics

Mithras: A Brief Description, O De La Beaujardiere, Vincent B. Wickwar, M J. Baron, J Holt, R M. Wand, W L. Oliver, P Bauer, M Blanc, C Senior, D Alcayde, G Caudal, J Foster, E Nielsen, R Heelis Jan 1984

Mithras: A Brief Description, O De La Beaujardiere, Vincent B. Wickwar, M J. Baron, J Holt, R M. Wand, W L. Oliver, P Bauer, M Blanc, C Senior, D Alcayde, G Caudal, J Foster, E Nielsen, R Heelis

All Physics Faculty Publications

Between May 1981 and June 1982 an intensive campaign of 33 coordinated observations was carried out using the three incoherent-scatter radars capable of probing the auroral zone. During this period the groups operating the Dynamic Explorer satellites and the STARE radar made special efforts to acquire data coincident with the radar observations. The objective of these MITHRAS experiments and subsequent analysis is to further our understanding of the interactions of the magnetosphere, the ionosphere, and the thermosphere, with special emphasis on local time/universal time variations. Three experimental modes with different time resolution and spatial coverage were used to examine different …


Thermospheric Neutral Wind At –39° Azimuth During The Daytime Sector At Sondrestrom, Vincent B. Wickwar Jan 1984

Thermospheric Neutral Wind At –39° Azimuth During The Daytime Sector At Sondrestrom, Vincent B. Wickwar

All Physics Faculty Publications

Measurements with the Sondrestrom radar have been used to examine the daytime thermospheric neutral wind and to relate that wind to other geophysical parameters. Ion drag is found to be particularly important for determining the wind pattern. However, evidence is presented that the wind pattern is significantly influenced by soft particle precipitation and, possibly, by Joule heating.


Observations Of Interplanetary Magnetic Field And Of Ionospheric Plasma Convection In The Vicinity Of The Dayside Polar Cleft, C R. Clauer, P M. Banks, A Q. Smith, T S. Jorgensen, E Friis-Christensen, S Vennerstrom, Vincent B. Wickwar Jan 1984

Observations Of Interplanetary Magnetic Field And Of Ionospheric Plasma Convection In The Vicinity Of The Dayside Polar Cleft, C R. Clauer, P M. Banks, A Q. Smith, T S. Jorgensen, E Friis-Christensen, S Vennerstrom, Vincent B. Wickwar

All Physics Faculty Publications

Dayside ionospheric convection at high latitudes has been examined during a series of experiments using the Sondrestrom radar together with ancillary observations of the interplanetary magnetic field (IMF) by the IMP‐8 spacecraft. The radar experiments obtained a latitude coverage of 67.6° Λ to 81.30° Λ and a temporal resolution of between 14 to 25 minutes. A total of 17 rotations through the dayside cleft region during April, June and July, 1983 have been examined. The observations show two convection cells with sunward flow at lower latitudes and antisunward flow at higher latitudes. The flow commonly rotates through a 180° angle …


A Theoretical F Region Study Of Ion Compositional And Temperature Variations In Response To Magnetospheric Storm Inputs, Jan Josef Sojka, Robert W. Schunk Jan 1984

A Theoretical F Region Study Of Ion Compositional And Temperature Variations In Response To Magnetospheric Storm Inputs, Jan Josef Sojka, Robert W. Schunk

All Physics Faculty Publications

The response of the polar ionosphere to magnetospheric storm inputs was modeled. During the “storm,” the spatial extent of the auroral oval, the intensity of the precipitating auroral electron energy flux, and the plasma convection pattern were varied with time. The convection pattern changed from a symmetric two-cell pattern with a 20-kV cross-tail potential to an asymmetric two-cell pattern with enhanced plasma flow in the dusk sector and a total cross-tail potential of 90 kV. During the storm there were significant changes in the ion temperature, ion composition, and molecular/atomic ion transition height. The storm time asymmetric convection pattern produced …


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.


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


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 …


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 …


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 …


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 …


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 …


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 …


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.


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 …


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 …


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.


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.


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.


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 …


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 …


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 …


A New Method For The Quantitative Determination Of Radon-222 In Natural Waters, Charles Whitlow Jan 1984

A New Method For The Quantitative Determination Of Radon-222 In Natural Waters, Charles Whitlow

Honors Theses

Several studies in the past have shown radon to be present in many natural waters including mineral springs, hot springs, rivers, lakes, and rainwater. A compilation of tables of radon concentration in mineral and hot springs all over the world was published by Kuroda in 1953. Most of this radon comes from radium and uranium minerals which the springs flow over. The radon concentration in lakes is from two major souces [sic]. One source is dissolved radium and the other is the inflow of high radon concentration groundwaters [sic].


Miocene Burrows Of Extinct Bear Dogs: Indication Of Early Denning Behavior Of Large Mammalian Carnivores, Robert M. Hunt Jr., Xue Xiang-Xu, Joshua Kaufman Jan 1984

Miocene Burrows Of Extinct Bear Dogs: Indication Of Early Denning Behavior Of Large Mammalian Carnivores, Robert M. Hunt Jr., Xue Xiang-Xu, Joshua Kaufman

Department of Earth and Atmospheric Sciences: Faculty Publications

Partial skeletons of four species of extinct carnivores have been found in their dens excavated in the floodplain of an early Miocene ephemeral braided stream at Agate Fossil Beds National Monument, Nebraska. Bear dogs (Carnivora: Amphicyonidae) were the principal occupants; their den dimensions and body size are similar to those of living wolves and hyenas. Discovery of this predator community extends the record of denning behavior of large mammalian carnivores to the early Miocene, 20 million years ago.


Relative Crop Yields On Different Soil Types, Pea And Lupin, R French Jan 1984

Relative Crop Yields On Different Soil Types, Pea And Lupin, R French

Experimental Summaries - Plant Research

1. Relative crop yields on different soil types - 84M50, 84M51, 84M52, 84M53. 2. Pea and lupin time of sowing trials - 84JE42, 84LG32, 84LG31, 84ME55, 84ME53, 84ME54, 84N065. 3. Effect of P-Pickel on Pea Nodulation - 84M64. 4. Lupin Agronomy - 84M55, 82ME52.


Cercospora Disease Of Subterranean Clover, Root Rot, Cereal Smuts, Rapeseed Diseases, M J. Barbetti Jan 1984

Cercospora Disease Of Subterranean Clover, Root Rot, Cereal Smuts, Rapeseed Diseases, M J. Barbetti

Experimental Summaries - Plant Research

Cercospora disease of subterranean clover: - . Susceptibility to and losses from cercospora on sub-clover cultivars. Locality: Bibby Springs, Cervantes. (84M073, 84M075, 84M076). Subterranean clover root rot: - Seed treatments for root rot control. Locality: Albany (84AL39); Scott River (84 BU11). Fungicide drenches for root rot control. Locality: Perth (84PE22) using intact cores from Albany and Scott River. Cultivar screening for resistance to root rot fungi. Locality: Perth (84PE24) with field plantings at Albany and Scott River. Methyl bromide fumigation for control of sub-clover root rot. Locality: Vasse Research Station (84V15). Two sites. Cereal smuts – Fungicidal control of loose …


Seed Ecology Of Weeds, A H. Cheam Jan 1984

Seed Ecology Of Weeds, A H. Cheam

Experimental Summaries - Plant Research

1. Emergence of weed seedlings from different soil depths 82MT49 Mt Barker Research Station 83MT4 Mt Barker Research Station 82NR12 Northam Research Station 83NR2 Northam Research Station 82C37 Chapman Research Station 83C3 Chapman Research Station

2. Longevity of buried weed seeds 82MT50 Mt Barker Research Station 83MT5 Mt Barker Research Station 82NR13 Northam Research Station 83NR3 Northam Research Station 82C38 Chapman Research Station 83C4 Chapman Research Station

3. Emergence of weed seedlings in relation to soil type and cultivation 82PE32 South Perth

4. Changes in the number of viable dock seeds in soil under different soil surface treatments 83V2 Vasse …


Crop Oil Additives To Herbicides, R Madin, A Lindsay Jan 1984

Crop Oil Additives To Herbicides, R Madin, A Lindsay

Experimental Summaries - Plant Research

Crop oil additives to herbicides - 84LG42.

Umbrella grass (Cyperus eragrostis) control in irrigated pasture - 85HA1.

Stinkwort control - 85NO5, 85PE14.

Ice plant (Mesembryanthem nodiflorum) control in crop and pasture - 83SG20, 83SG21.


Comparison Of Conventional Boomspray And C.D.A. Equipment For Weed Control In Cereals, J R. Peirce, B. J. Rayner Jan 1984

Comparison Of Conventional Boomspray And C.D.A. Equipment For Weed Control In Cereals, J R. Peirce, B. J. Rayner

Experimental Summaries - Plant Research

l. 84N067 - Ryegrass

2. 84N068 - Capeweed

3. 84ME69 - Capeweed

4. 84 (40-41) - Ryegrass & Radish

5. C.D.A. - Capeweed

6. Boomspray Capeweed

Comparison of conventional boomspray and C.D.A. equipment for weed control in cereals – 84C40, 84C41, 84ME69, 84NO67, 84NO68.

Effectiveness of Roundup C.T. with and without crop oils applied through Controlled Droplet Applicators (C.D.A.) – Wongan Hills Research Station.

Effectiveness of Roundup C.T. with and without crop oils applied through a conventional boomspray – Wongan Hills Research Station.


Soil Acidity In The Eastern Wheatbelt, W Porter, S Carr, J Garlett Jan 1984

Soil Acidity In The Eastern Wheatbelt, W Porter, S Carr, J Garlett

Experimental Summaries - Plant Research

1. Surface incorporated lime: 80M30 - Wheat. 82ME54 - Lupins. 82TS33 - Wheat. 80M31 - Wheat. 81M5 - Medic. 2. Subsoil banded lime: 81M54 - Lupins. 3. Whole profile incorporated lime: 82M5 - Wheat. 82ME10 - Wheat. 4. Acid tolerant species: 84ME50 - interaction with N. 84ME51 - interaction with PP. 84ME52 - growth on non-acid sand.


Effect Of Various Crop And Pasture Species On The Growth Of A Subsequent Wheat Crop, N Delroy, J W. Bowden, I Rowland, M Ralph, R Lunt, M Baker Jan 1984

Effect Of Various Crop And Pasture Species On The Growth Of A Subsequent Wheat Crop, N Delroy, J W. Bowden, I Rowland, M Ralph, R Lunt, M Baker

Experimental Summaries - Plant Research

83WH29: The effect of various crop and pasture species on the growth of a subsequent wheat crop. Aim: To characterise the effect of various crop and pasture species on the growth and yield components of a subsequent wheat crop with special emphasis on the nitrogen nutrition of that crop. To provide validation data for modelling wheat growth and nitrogen uptake. Measurements: Factors to be monitored through time were; Soil moisture profiles; Mineral nitrogen profiles; Root growth profiles; Top growth and nitrogen uptake; Development score; Incidence of disease and pests.

Seasonal notes, trial design, weed diseases and pests. Results: The results …