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1994

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Articles 1861 - 1890 of 2037

Full-Text Articles in Physical Sciences and Mathematics

Land Resources Of The Northam Region, Neil Clifton Lantzke, I Fulton Jan 1994

Land Resources Of The Northam Region, Neil Clifton Lantzke, I Fulton

Land resources series

This report presents soil and landform mapping of about one million hectares in the Avon Valley and central wheatbelt of Western Australia at scale of 1:100,000. The study area spans from the lateritic plateau of the Darling Range to the broad, flat landscape of the wheatbelt and covers four broad physiographic regions: • the Zone of Ancient Drainage; • the Zone of Rejuvenated Drainage; • the West Kokeby Zone; and • the Darling Range Zone. Twenty-five soil landscape units were identified and mapped on the accompanying map sheets. A soil landscape unit is an area of land that occurs in …


An Inventory And Condition Survey Of The Murchison River Catchment, Western Australia, Peter James Curry, A L. Payne, K A. Leighton, P Hennig, D A. Blood Jan 1994

An Inventory And Condition Survey Of The Murchison River Catchment, Western Australia, Peter James Curry, A L. Payne, K A. Leighton, P Hennig, D A. Blood

Technical Bulletins

The inventory and condition survey of the Murchison River catchment and surrounds, undertaken by the Department of Agriculture between 1985 and 1988, describes and maps the natural resources of the region’s pastoral leasehold land. This survey report provides a baseline record of the existence and condition of the natural area’s resources, to assist with the planning and implementation of land management practices. The report identified and described the condition of soils, landforms, vegetation, habitat, ecosystems, and declared plants and animals. It also assessed the impact of pastoralism and made land management recommendations. The area surveyed by field work during 1985-88 …


Transonic Inviscid Disc Flows In The Schwarzschild Metric – I, Menas Kafatos, Ruixin Yang Jan 1994

Transonic Inviscid Disc Flows In The Schwarzschild Metric – I, Menas Kafatos, Ruixin Yang

Mathematics, Physics, and Computer Science Faculty Articles and Research

The coupled hydrodynamic equations governing equatorial flows applicable to inviscid disc accretion in the Schwarzschild metric are solved analytically and numerically. Here, we concentrate on the transonic solutions, that represent physically allowed accretion on to black holes. A polytropic equation linking gas pressure and density is assumed, and solutions are obtained for different conditions, such as isothermal and adiabatic gas flows. The dependence of those solutions on the angular momentum is explored. Under certain conditions, when there exist multiple possible sonic points, the numerical simulation automatically zeros in to the unique transonic solution passing through one of the sonic points.


Modelling Sun-Aligned Polar Cap Arcs, D. J. Crain, Jan Josef Sojka, Robert W. Schunk, Lie Zhu Jan 1994

Modelling Sun-Aligned Polar Cap Arcs, D. J. Crain, Jan Josef Sojka, Robert W. Schunk, Lie Zhu

All Physics Faculty Publications

We present results of a new model of the time-dependent ionospheric response to a generalized steady state Sun-aligned (SA) arc structure. The thermal and plasma structure of a “prototype” arc is compared to the general features of observed SA arcs. We find that the general features of electron density, Ne , electron temperature, Te , and ion temperature, Ti , are determined by the distribution of the particle precipitation and E × B convection associated with the SA arc. The model results are extended to predict the possible variation of Ne, Te , and …


Ionospheric Response To Traveling Convection Twin Vortices, Robert W. Schunk, Lie Zhu, Jan Josef Sojka Jan 1994

Ionospheric Response To Traveling Convection Twin Vortices, Robert W. Schunk, Lie Zhu, Jan Josef Sojka

All Physics Faculty Publications

Traveling convection twin vortices have been observed for several years. At ionospheric altitudes, the twin vortices correspond to spatially localized, transient structures embedded in a large‐scale background convection pattern. The convection vortices are typically observed in the morning and evening regions. They are aligned predominantly in the east‐west direction and have a horizontal extent of from 500–1000 km. Associated with the twin vortices are enhanced electric fields, particle precipitation, and an upward/downward field‐aligned current pair. Once formed, the twin vortex structures propagate in the tailward direction at speeds of several km/s, but they weaken as they propagate and only last …


Model Study Of Multiple Polar Cap Arcs: Occurrence And Spacing, Lie Zhu, Jan Josef Sojka, Robert W. Schunk, D. J. Crain Jan 1994

Model Study Of Multiple Polar Cap Arcs: Occurrence And Spacing, Lie Zhu, Jan Josef Sojka, Robert W. Schunk, D. J. Crain

All Physics Faculty Publications

A new scenario for the formation of multiple polar cap arcs is proposed based on the results from a time‐dependent electrodynamic model of polar cap arcs developed by Zhu et al. [1993]. The results suggest that the appearance of multiple polar cap arcs may not be due to multiple structures in the magnetospheric source region, but instead, may primarily be determined by the coupled magnetosphere‐ionosphere system in which the ionosphere plays an active role. It was found that with the same magnetospheric driver, a strong ionospheric background convection and an ionospheric background Hall conductance in the range of from 0.5 …


Theoretical Study Of Polar Cap Arcs: Time-Dependent Model And Its Applications, Lie Zhu, Jan Josef Sojka, Robert W. Schunk, D. J. Crain Jan 1994

Theoretical Study Of Polar Cap Arcs: Time-Dependent Model And Its Applications, Lie Zhu, Jan Josef Sojka, Robert W. Schunk, D. J. Crain

All Physics Faculty Publications

A time-dependent theoretical model of polar cap arcs developed during the Coupling, Energetics, and Dynamics of Atmospheric Regions/High-Latitude Plasma Structures (CEDAR/HLPS) campaigns in the past two years is briefly described. In the model the electrodynamics of the polar cap arcs are treated self-consistently in the frame of the coupled magnetosphere-ionosphere system. The preliminary simulation results of the temporal evolution and spatial structure of the polar cap arcs for both winter and summer conditions are presented. The model can be used to conduct both the model-observation study of specific features of the polar cap arcs and the quantitative theoretical study of …


Taking A Cat Map: Genome Analysis By Supercomputer, Jose V. Lopez Jan 1994

Taking A Cat Map: Genome Analysis By Supercomputer, Jose V. Lopez

Marine & Environmental Sciences Faculty Articles

No abstract provided.


Vertical Variation In Groundwater Chemistry Inferred From Fluid Specific-Conductance Well Logging Of The Snake River Plain Basalt Aquifer, Idaho National Engineering Laboratory, Southeastern Idaho, Spencer H. Wood, William Bennecke Jan 1994

Vertical Variation In Groundwater Chemistry Inferred From Fluid Specific-Conductance Well Logging Of The Snake River Plain Basalt Aquifer, Idaho National Engineering Laboratory, Southeastern Idaho, Spencer H. Wood, William Bennecke

Geosciences Faculty Publications and Presentations

Well logging of electrical fluid specific conductance (Cs) shows that permeable zones yielding ground water to intrawell flows and the water columns in some wells at INEL have highly different chemistry, with as much as a two-fold variation in Cs). This suggests that dedicated pump sampling of ground water in the aquifer may not be representative of the chemistry of the waste plumes migrating southwest of the nuclear facilities. Natural background Cs in basalt-aquifer ground water of this part of the Snake River Plain aquifer is less than 325µS/cm (microSiemans/cm), and total dissolved solids in …


Environmental Attitudes And Knowledge: An International Comparison Among Business Students, Raymond Benton Jr., G. Ray Funkhouser Jan 1994

Environmental Attitudes And Knowledge: An International Comparison Among Business Students, Raymond Benton Jr., G. Ray Funkhouser

School of Business: Faculty Publications and Other Works

This article investigates international differences in environmental knowledge and attitudes among business administration students. The Environmental Knowledge and Attitude Scale, developed by Maloney, Ward, and Braucht (1975) and used by Synodinos (1990), was administered to 85 upperdivision business administration students at Loyola University Chicago and 111 upperdivision business students at the National University of Singapore. No significant differences were found between the two samples on the Knowledge, Concern, or Willingness to Act subscales. The United States students' higher mean score on the Actual Behavior subscale was significant but may only reflect relative possibilities for participation in environmental activities. Overall, the …


Source Rock Geochemistry Of The Southern Tyee Basin, Southwest Oregon, David E. Long Jan 1994

Source Rock Geochemistry Of The Southern Tyee Basin, Southwest Oregon, David E. Long

Dissertations and Theses

This study examined source rock geochemistry of the southern Tyee Basin. Total organic carbon, rock-eval pyrolysis, vitrinite reflectance, thermal alteration index and visual assessments were performed on splits from cutting samples from five wells and on outcrop samples from four measured sections. Organic matter was found to be dispersed, averaging about 0.5 weight percent. The organic matter is primarily terrestrial in origin, or type I l l , with low potential for gas production and no oil potential. Three coal samples are clearly the richest sources of organic matter examined in this study.


Fossil Charcoal In Cretaceous-Tertiary Boundary Strata: Evidence For Catastrophic Firestorm And Megawave, Michael A. Kruge Jan 1994

Fossil Charcoal In Cretaceous-Tertiary Boundary Strata: Evidence For Catastrophic Firestorm And Megawave, Michael A. Kruge

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Organic matter separated from calcareous sandstone from the upper portion of a deep-water tsunami deposit at Arroyo el Mimbral, Taumalipas (Mexico), which marks the biostratigraphically-defined Cretaceous-Tertiary boundary, consists primarily of fossil charcoal, including semifusinite and pyrofusinite. Analytical pyrolysis-gas chromatography-mass spectrometry revealed the highly aromatic and polyaromatic character of the organic matter assemblage, typical of the products of partial combustion. The organic matter probably originated as terrestrial vegetation that was caught in a firestorm and subsequently transported far offshore in the backwash of a megawave. These data are consistent with the hypothesis of combustion of large masses of vegetation triggered by …


Geochemical Characterization Of Maceral Concentrates From Herrin No. 6 Coal (Illinois Basin) And Lower Toarcian Shale Kerogen (Paris Basin), B Artur Stankiewicz, Michael A. Kruge, John C. Crelling Jan 1994

Geochemical Characterization Of Maceral Concentrates From Herrin No. 6 Coal (Illinois Basin) And Lower Toarcian Shale Kerogen (Paris Basin), B Artur Stankiewicz, Michael A. Kruge, John C. Crelling

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Density gradient centrifugation (DGC) is a physical method for the separation of sedimentary organic matter into its constituents. Using DGC, it is possible to prepare maceral concentrates from a single sample, which are amenable to microanalysis. DGC fractions from a coal sample from the Illinois Basin (Herrin No. 6, Upper Carboniferous) and from the kerogen of a marine shale sample from the Paris Basin (Lower Toarcian) were analyzed by flash pyrolysis-gas chromatography-mass spectrometry, after extraction by CH2Cl2.

Chemical differences between the coal DGC fractions are the easiest to recognize, indicating very distinctive biological precursors. For example, …


Flash Pyrolysis-Gas Chromatography/Mass Spectrometry Of Lower Kittanning Vitrinites: Changes In The Distributions Of Polyaromatic Hydrocarbons As A Function Of Coal Rank, Michael A. Kruge, David F. Bensley Jan 1994

Flash Pyrolysis-Gas Chromatography/Mass Spectrometry Of Lower Kittanning Vitrinites: Changes In The Distributions Of Polyaromatic Hydrocarbons As A Function Of Coal Rank, Michael A. Kruge, David F. Bensley

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Chemical analyses restricted to a single coal maceral permit a focus on rank effects without concern for variations in organic matter type. Vitrinite concentrates of high purity were isolated from coal samples of the Lower Kittanning seam by multi-step density gradient centrifugation, with reflectances ranging from 0.66 to 1.39% Rmax. In addition to the previously recognized losses of phenolic compounds, the vitrinite pyrolyzates exhibit marked increases in relative concentrations of tri- and tetraaromatic hydrocarbons (especially benzo[a]fluorene, methyl-phenanthrenes, methylfluorenes and methylchrysenes) above 0.9% Rmax, i.e., beyond the "second coalification jump" of Teichmüller. Thus, petrographically-recognizable physical transformations are shown …


Serravallian Shales In The Monte Dei Corvi Pelagic Sequence (Ancona, Italy): An Organic Geochemical Perspective, Michael A. Kruge, B Artur Stankiewicz, Alessandro Montanari Jan 1994

Serravallian Shales In The Monte Dei Corvi Pelagic Sequence (Ancona, Italy): An Organic Geochemical Perspective, Michael A. Kruge, B Artur Stankiewicz, Alessandro Montanari

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

In addition to the predominant marly lithologies, the Serravallian-Tortonian sequence at Monte dei Corvi (MDC), south of Ancona, Italy, contains at least 85 thin, dark calcareous shales. Such shales, averaging 14 cm in thickness, comprise 9% of the total Serravallian sequence. Sixteen of them were sampled for a preliminary organic geochemical evaluation. All the MDC shales appear to have been deposited during periodic anoxic events, as demonstrated by the presence of significant quantities of organic matter and authigenic pyrite. The degree of anoxicity (and thus the amount of organic matter preserved) appears to have differed from one event to the …


Opportunities For Integration In Institutional Arrangements For Water Management In The Yukon, Patrick James Dooling Jan 1994

Opportunities For Integration In Institutional Arrangements For Water Management In The Yukon, Patrick James Dooling

Theses and Dissertations (Comprehensive)

The history of water resources management in the Yukon has been characterized by conflict. This problem is due to the failure to address the interrelationships between water and land resources. Although many parts of the Yukon remain largely undisturbed wilderness areas, development pressures place increasing demands on Territorial water resources. To ensure these stresses do not degrade Yukon waters to the extent common in many Canadian regions, a reevaluation of the legal and administrative arrangements for water management in the Yukon is required. A majority of the legislation pertaining to water management in the Yukon was introduced in the 1970s …


Molecular-Dynamics Simulations Of Some Baxf4 Compounds, John Flocken, Z. Mo, Wai-Ning Mei, John R. Hardy, Dorian Hatch Jan 1994

Molecular-Dynamics Simulations Of Some Baxf4 Compounds, John Flocken, Z. Mo, Wai-Ning Mei, John R. Hardy, Dorian Hatch

Physics Faculty Publications

We have carried out molecular-dynamics simulations on BaXF4 compounds, where X is Mg, Mn, or Zn. Ab initio potentials, with no adjustable parameters, were used to obtain short-range interactions between ion pairs. We found a polar ground-state structure which is in agreement with the A21am space group reported experimentally. We were able to reverse polarization in BaMgF4 at high temperatures, using large fields, but were unable to reverse polarization in the other compounds. The second-order phase transition in the Mn compound at 250 K was reproduced. We believe this to be the first extension of …


Low Internal Magnetic Fields In Anisotropic Superconductors, Allan J. Greer Jr. Jan 1994

Low Internal Magnetic Fields In Anisotropic Superconductors, Allan J. Greer Jr.

Dissertations, Theses, and Masters Projects

This thesis is a theoretical, numerical study of the magnetic fields which exist in the anisotropic, high temperature superconductors like $YBa\sb2Cu\sb3O\sb{7-\delta}$, or YBCO for short, using both the anisotropic London theory and simulations based on existing muon spin rotation techniques. The thesis first describes the muon spin rotation ($\mu$SR) techniques, and then gives a brief discussion of superconductivity with regard to the London theory of anisotropic, type II superconductors. Next, numerical results of the application of this theory to YBCO are presented. Three dimensional surface plots of the magnetic field components within the flux line lattice (FLL) are shown, as …


A Simple Description Of Coherence, William Moebs, Jeff Sanny Jan 1994

A Simple Description Of Coherence, William Moebs, Jeff Sanny

Physics Faculty Works

No abstract provided.


5-Acetyl[2.2]Paracyclophane, Sergey V. Lindeman, Yuri T. Struchkov, Vyacheslav N. Guryshev Jan 1994

5-Acetyl[2.2]Paracyclophane, Sergey V. Lindeman, Yuri T. Struchkov, Vyacheslav N. Guryshev

Chemistry Faculty Research and Publications

The title compound 5-acetyltricyclo[8.2.2.24,7]hexa-deca-4,6,10,12,13,15-hexaene, C18H18O,is the first example of a mono-π-substituted [2.2]paracyclophane to be structurally characterized. The average bending angles are α = 13.2 and β = 9.9°. The distance between the 'bottoms' of the practically parallel boat-like benzene nuclei is 3.098(2) Å. The π conjugation between the acetyl group and the substituted benzene cycle is negligible (rotation angle ca 45°) because of steric hindrance.


An M-Carboranedicarboxylic Acid Dianilide, Sergey V. Lindeman, Georgii A. Kats, Lyudmila G. Komarova Jan 1994

An M-Carboranedicarboxylic Acid Dianilide, Sergey V. Lindeman, Georgii A. Kats, Lyudmila G. Komarova

Chemistry Faculty Research and Publications

The crystal structure of the 'non hydrogen-bonded' (according to IR data) polymorph of 1,7-bis(phenylcarbamoyl)-1,7-dicarba-closo-dodecaborane(12), C16-H22B10N2O2, has been determined. The two phenylamide groups have a Z configuration [the torsion angles 0-C-N-C are -2.3 (5) and -3.0 (5)°]. As a result both 'active' protons of these groups are almost completely shielded by other H atoms of the neighbouring carborane nucleus and phenyl substituents, and, therefore, no hydrogen-bonding contacts are found.


Measurement Of The Branching Fraction For D+K-++, Balest, R.; Et Al., M. Thulasidas Jan 1994

Measurement Of The Branching Fraction For D+K-++, Balest, R.; Et Al., M. Thulasidas

Research Collection School Of Computing and Information Systems

Using the CLEO II detector at the Cornell Electron Storage Ring we have measured the ratio of branching fractions, B(D+K-++)/(D0K-+)=2.350.160.16. Our recent measurement of scrB(D0K-+) then gives scrB(D+K-++)=(9.30.60.8)%.


A Fuzzy Logic-Based Foundation For Analyzing Imprecise Conflicting Requirements, J. Yen, Xiaoqing Frank Liu Jan 1994

A Fuzzy Logic-Based Foundation For Analyzing Imprecise Conflicting Requirements, J. Yen, Xiaoqing Frank Liu

Computer Science Faculty Research & Creative Works

Imprecise requirements are represented by the canonical form in test-score semantics. The concepts of feasibility, satisfiability, and specificity are formalized based on the fuzzy sets. The relationships between requirements are classified to be conflicting and cooperative. A feasible overall requirement can thus be formulated based on the tradeoff analysis of the conflicting requirements by using fuzzy multi-criteria optimization technique


Parameter Tuning For The Max Expert System, Christopher J. Merz, M. J. Pazzani Jan 1994

Parameter Tuning For The Max Expert System, Christopher J. Merz, M. J. Pazzani

Computer Science Faculty Research & Creative Works

We investigate methods for tuning numeric parameters in Nynex MAX, a telephone trouble screening expert system. Steepest descent, hillclimbing, and simulated annealing parameter adjustment strategies are applied to the problems of maximizing classification accuracy and minimizing misclassification cost. For both of those optimization problems we evaluate each algorithm''s ability to tune initial parameters for several situations


Skin Cancer Diagnosis Using Hierarchical Neural Networks And Fuzzy Logic, Hsi-Chieh Lee Jan 1994

Skin Cancer Diagnosis Using Hierarchical Neural Networks And Fuzzy Logic, Hsi-Chieh Lee

Masters Theses

"Skin cancer, the most common cancer in the United States that affects about 600,000 Americans every year, accounts for 1 % of all cancer deaths. Among all, Malignant Melanoma is the most virulent form of skin cancer that is responsible for 75% of all deaths from skin cancer. In 1992, approximately 32,000 people are expected to develop melanoma and about 6,700 will die. However, even malignant melanoma can be treated successfully if detected in the early phase. Therefore, our research goal is to diagnose skin cancer, especially malignant melanoma.

In this study, only the digitized images obtained from color tumor …


Direct Simulation Monte Carlo For Thin Film Bearings, Alejandro Garcia, B. Alder, F. J. Alexander Jan 1994

Direct Simulation Monte Carlo For Thin Film Bearings, Alejandro Garcia, B. Alder, F. J. Alexander

Alejandro Garcia

The direct simulation Monte Carlo (DSMC) scheme is used to study the gas flow under a read/write head positioned nanometers above a moving disk drive platter (the slider bearing problem). In most cases, impressive agreement is found between the particle-based simulation and numerical solutions of the continuum hydrodynamic Reynolds equation which has been corrected for slip. However, at very high platter speeds the gas is far from equilibrium, and the load capacity for the slider bearing cannot be accurately computed from the hydrodynamic pressure.


Microscopic Simulation Of Dilute Gases With Adjustable Transport Coefficients, Alejandro Garcia, F. Baras, M. Malek Mansour Jan 1994

Microscopic Simulation Of Dilute Gases With Adjustable Transport Coefficients, Alejandro Garcia, F. Baras, M. Malek Mansour

Alejandro Garcia

The Bird algorithm is a computationally efficient method for simulating dilute gas flows. However, due to the relatively large transport coefficients at low densities, high Rayleigh or Reynolds numbers are difficult to achieve by this technique. We present a modified version of the Bird algorithm in which the relaxation processes are enhanced and the transport coefficients reduced, while preserving the correct equilibrium and nonequilibrium fluid properties. The present algorithm is found to be two to three orders of magnitude faster than molecular dynamics for simulating complex hydrodynamical flows.


Dynamic Phenomena In Superconducting Oxides By Esr, Juana Vivó Acrivos, Lei Chen, C. M. Burch, P. Metcalf, J. M. Honig, R. S. Liu, K. K. Singh Jan 1994

Dynamic Phenomena In Superconducting Oxides By Esr, Juana Vivó Acrivos, Lei Chen, C. M. Burch, P. Metcalf, J. M. Honig, R. S. Liu, K. K. Singh

Juana Vivó Acrivos

Dynamic electron spin resonance (ESR) measurements compare the paramagnetic and antiferromagnetic (AF) properties of superconducting oxides in the range 4 K to room temperature, at 8 MHz and 9.36 GHz. Two are derivatives of YBa2Cu30 7: 1: Nd(Nd0.05Ba0.95 )2Cu30 7, Te0 =72 K and II: Y0.2Cao.8Sr2[Cu2(Tlo.5Pb0.5 )]07, Te0 =108 K and two are cases where AF ordering dominates the weak superconductivity: III: Nb01.1> 1. 25 ~Teo~ 10 K and IV: La2Ni04.00, 70 K :::: Teo:::: 40 K. At temperatures 298:::: T:::: 64 K, the ESR absorption by I indicates orthorhombic symmetry. The peaks at Ke =2.06, gb =2.13, and Ka …


Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle Jan 1994

Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle

Michael Sinensky

No abstract provided.


The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton Jan 1994

The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton

Michael Sinensky

The conversion of mammalian prelamin A to mature lamin A proceeds through the removal of 18 amino acids from the carboxyl terminus. The initial step in this processing is the isoprenylation of a CAAX box cysteine. This proteolytic event is distinctive for prelamin A among the known prenylated mammalian proteins. Since the carboxyl terminus of prelamin A is removed during maturation, it is not obvious that this protein would undergo the two reactions subsequent to prenylation observed in other CAAX box proteins-the endoproteolytic removal of the carboxyl-terminal 3 amino acids and the subsequent methylation of the now carboxyl-terminal cysteine. To …