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2000

University of Kentucky

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Articles 1 - 30 of 51

Full-Text Articles in Physical Sciences and Mathematics

Continuum Pumping Of [Fe Ii] In The Orion Nebula, E. M. Verner, D. A. Verner, J. A. Baldwin, Gary J. Ferland, P. G. Martin Nov 2000

Continuum Pumping Of [Fe Ii] In The Orion Nebula, E. M. Verner, D. A. Verner, J. A. Baldwin, Gary J. Ferland, P. G. Martin

Physics and Astronomy Faculty Publications

This paper presents detailed comparisons between numerical simulations of Fe II emission spectra and recent high-resolution and signal-to-noise spectra of the Orion Nebula. We have identified 40 [Fe II] lines in the spectrum, allowing extensive comparisons between theory and observations. The identifications are based on predictions of a realistic model of the Fe II atom, which includes the lowest 371 levels (all levels up to 11.6 eV). We investigate the dependence of the spectrum on electron density and on pumping by the stellar continuum. Orion is important because it provides a relatively simple environment in which to test complex simulations. …


Simulation Of Daily And Monthly Stream Discharge From Small Watersheds Using The Swat Model, Crystal A. Spruill, Stephen R. Workman, Joseph L. Taraba Nov 2000

Simulation Of Daily And Monthly Stream Discharge From Small Watersheds Using The Swat Model, Crystal A. Spruill, Stephen R. Workman, Joseph L. Taraba

Biosystems and Agricultural Engineering Faculty Publications

The Soil and Water Assessment Tool (SWAT) was evaluated and parameter sensitivities were determined while modeling daily streamflows in a small central Kentucky watershed over a two-year period. Streamflow data from 1996 were used to calibrate the model and streamflow data from 1995 were used for evaluation. The model adequately predicted the trends in daily streamflow during this period although Nash-Sutcliffe R2 values were –0.04 and 0.19 for 1995 and 1996, respectively. The model poorly predicted the timing of some peak flow values and recession rates during the last half of 1995. Excluding daily peak flow values from August …


Metallic Nanoscale Fibers From Stable Iodine-Doped Carbon Nanotubes, Peter C. Eklund, Leonid Grigorian, Keith A. Williams, Gamini U. Sumanasekera, Shaoli Fang Oct 2000

Metallic Nanoscale Fibers From Stable Iodine-Doped Carbon Nanotubes, Peter C. Eklund, Leonid Grigorian, Keith A. Williams, Gamini U. Sumanasekera, Shaoli Fang

Physics and Astronomy Faculty Patents

A method of doping involves soaking single-walled carbon nanotubes in molten iodine. Excess physisorbed iodine may then be removed by annealing.


Observational Constraints On The Internal Velocity Field Of Quasar Emission-Line Clouds, Mark Bottorff, Gary J. Ferland, Jack Baldwin, Kirk Korista Oct 2000

Observational Constraints On The Internal Velocity Field Of Quasar Emission-Line Clouds, Mark Bottorff, Gary J. Ferland, Jack Baldwin, Kirk Korista

Physics and Astronomy Faculty Publications

This paper addresses the question, what does the spectrum of a typical quasar reveal about the velocity structure within its broad emission line region clouds? Turbulent (i.e., nonthermal) broadening of spectral lines can be due to macroturbulence or microturbulence. Microturbulence affects line formation and the emitted spectrum and may be required to account for the observed smoothness of the line profiles. The velocity field is crucial since it addresses the fundamental nature of the individual clouds and the global structure of the active galactic nuclei (AGNs) environment. For example, stellar winds or magnetically confined blobs might be highly microturbulent, requiring …


Pride Water Quality Assessment Report: I. Problems And Programs, Kentucky Water Resources Research Institute. University Of Kentucky Sep 2000

Pride Water Quality Assessment Report: I. Problems And Programs, Kentucky Water Resources Research Institute. University Of Kentucky

KWRRI Research Reports

This report provides an overview of the water quality problems and associated state and federal programs in the 40 counties that make up the PRIDE region. The 2000 Kentucky 305(b) stream assessment has identified over 1000 miles of impaired stream within the region. The major cause of pollution in the region is related to problems with pathogens. Much of these problems are related to straight pipes and failing septic and wastewater systems. It has been estimated that there are over 35,000 straight pipes and failing septic systems in the PRIDE region. A second major environmental impact in the region is …


Pride Water Quality Assessment Report: Iii. Existing And Proposed Monitoring Network, Kentucky Water Resources Research Institute, University Of Kentucky Sep 2000

Pride Water Quality Assessment Report: Iii. Existing And Proposed Monitoring Network, Kentucky Water Resources Research Institute, University Of Kentucky

KWRRI Research Reports

This document provides a recommendation for proposed sampling sites in support of the general water quality assessment of the 40 county PRIDE region. A general assessment of the associated environmental problems and programs in the region can be found in the companion report: PRIDE Water Quality Assessment Report I: Problems and Programs while the report PRIDE Water Quality Assessment Report II: Chemical, Biological and Habitat Assessments provides a 10 year baseline assessment of environmental conditions in the region as measured by indicators of pH, fecal coliforms, habitat assessment, and macro-invertebrate assessment.


Pride Water Quality Assessment Report: Ii. Chemical, Biological And Habitat Assessments, Kentucky Water Resources Research Institute, University Of Kentucky Sep 2000

Pride Water Quality Assessment Report: Ii. Chemical, Biological And Habitat Assessments, Kentucky Water Resources Research Institute, University Of Kentucky

KWRRI Research Reports

The efficient utilization of federal funds in improving the water quality and aquatic habitat of the region requires a mechanism for assessing and evaluating the impacts of the proposed and ongoing projects as well as some mechanism for prioritizing the allocation of additional funds. In order to evaluate the effectiveness of these projects it is important to provide a formal monitoring and assessment program based on sound scientific principles. This report provides an initial 10 year baseline assessment of the existing water quality conditions in the 40 county PRIDE·region for the purpose of evaluating the impacts of the PRIDE programs …


Clathrate Structure For Electronic And Electro-Optic Applications, Leonid Grigorian, Peter C. Eklund, Shaoli Fang Aug 2000

Clathrate Structure For Electronic And Electro-Optic Applications, Leonid Grigorian, Peter C. Eklund, Shaoli Fang

Physics and Astronomy Faculty Patents

A method including the steps of (a) depositing a metal layer on a selected portion of a silicon substrate under a first set of predetermined conditions to form an metal silicide layer and an intermediate n-type silicon layer; and (b) exposing the metal silicide layer and the n-type silicon layer to a second set of predetermined conditions to form a silicon clathrate film on the selected portion of the silicon substrate, where the intermediate n-type silicon layer acts to bond the silicon clathrate to the silicon substrate to form a silicon clathrate structure.


The Narrow-Line Region In The Seyfert 2 Galaxy Ngc 3393, Andrew J. Cooke, J. A. Baldwin, Gary J. Ferland, Hagai Netzer, Andrew S. Wilson Aug 2000

The Narrow-Line Region In The Seyfert 2 Galaxy Ngc 3393, Andrew J. Cooke, J. A. Baldwin, Gary J. Ferland, Hagai Netzer, Andrew S. Wilson

Physics and Astronomy Faculty Publications

The narrow-line region (NLR) of the Seyfert 2 galaxy NGC 3393 is dominated by a symmetric structure which appears as S-shaped arms in Hubble Space Telescope (HST) images. These arms, which occupy the central few arcseconds of the nucleus, border a linear, triple-lobed radio source. We use HST imaging and spectra, ground-based optical images, long-slit spectra, Fabry-Perot imaging spectroscopy, and VLA radio data to perform a detailed investigation of the kinematics and ionization of the line-emitting gas in NGC 3393 and of its relationship with the relativistic gas responsible for the radio emission. The excitation map [O III] …


Thermolectric Materials Based On Intercalated Layered Metallic Systems, Peter C. Eklund, Leonid Grigorian, Keith A. Williams, Gamini U. Sumanasekera Jul 2000

Thermolectric Materials Based On Intercalated Layered Metallic Systems, Peter C. Eklund, Leonid Grigorian, Keith A. Williams, Gamini U. Sumanasekera

Physics and Astronomy Faculty Patents

A novel thermoelectric material in the form of a unit cell including a first reagent intercalated as a semiconducting layer into a metallic layered host and a method for producing the thermoelectric material are disclosed. The unit cell is characterized by a Seebeck coefficient S of 80-140 μV/K° and an electrical conductivity σ of 103 -104 (Ωcm)-1, as well as a figure of merit Z of about 2×10-3 K-1 at 100° K.


The Primordial Helium Abundance: Toward Understanding And Removing The Cosmic Scatter In The Dy/Dz Relation, D. R. Ballantyne, Gary J. Ferland, P. G. Martin Jun 2000

The Primordial Helium Abundance: Toward Understanding And Removing The Cosmic Scatter In The Dy/Dz Relation, D. R. Ballantyne, Gary J. Ferland, P. G. Martin

Physics and Astronomy Faculty Publications

We present results from photoionization models of low-metallicity H II regions. These nebulae form the basis for measuring the primordial helium abundance. Our models show that the helium ionization correction factor (ICF) can be nonnegligible for nebulae excited by stars with effective temperatures larger than 40,000 K. Furthermore, we find that when the effective temperature rises to above 45,000 K, the ICF can be significantly negative. This result is independent of the choice of stellar atmosphere. However, if an H II region has an [O III] λ5007/[O I] λ6300 ratio greater than 300, then our models show that, regardless of …


Infrared Classification Of Galactic Objects, Željko Ivezić, Moshe Elitzur May 2000

Infrared Classification Of Galactic Objects, Željko Ivezić, Moshe Elitzur

Physics and Astronomy Faculty Publications

Unbiased analysis shows that IRAS data reliably differentiate between the early and late stages of stellar evolution because objects at these stages clearly segregate in infrared color-color diagrams. Structure in these diagrams is primarily controlled by the density distribution of circumstellar dust. The density profile around older objects is the steepest, declining as r-2, while young objects have profiles that vary as r-3/2 and flatter. The different density profiles reflect the different dynamics that govern the different environments. Our analysis also shows that high-mass star formation is strongly concentrated within ~5 kpc around the Galactic center, in …


Properties Of Dust Grains In Planetary Nebulae. I. The Ionized Region Of Ngc 6445, Peter A. M. Van Hoof, Griet C. Van De Steene, Douwe A. Beintema, P. G. Martin, Stuart R. Pottasch, Gary J. Ferland Mar 2000

Properties Of Dust Grains In Planetary Nebulae. I. The Ionized Region Of Ngc 6445, Peter A. M. Van Hoof, Griet C. Van De Steene, Douwe A. Beintema, P. G. Martin, Stuart R. Pottasch, Gary J. Ferland

Physics and Astronomy Faculty Publications

One of the factors influencing the spectral evolution of a planetary nebula is the fate of the dust grains that are emitting the infrared continuum. Several processes have been proposed that either destroy the grains or remove them from the ionized region. To test whether these processes are effective, we study new infrared spectra of the evolved nebula NGC 6445. These data show that the thermal emission from the grains is very cool and has a low flux compared to Hβ. A model of the ionized region is constructed, using the photoionization code CLOUDY 90.05. Based on this model, we …


Changes In Alfalfa Breeding — Where Is Alfalfa Headed?, Becky Greenwald Feb 2000

Changes In Alfalfa Breeding — Where Is Alfalfa Headed?, Becky Greenwald

Kentucky Alfalfa and Stored Forage Conference

Alfalfa didn't earn the title "Queen of the Forages" just because of its good looks on rolling hills or sweet smell at harvest. Alfalfa was first described nearly 2,500 years ago, in 490 B.C in the desert regions of what is now Iran. From the Middle East, alfalfa was taken into Europe and South America by invading armies, explorers, and missionaries.


Little Known Facts About Alfalfa, Don Ball Feb 2000

Little Known Facts About Alfalfa, Don Ball

Kentucky Alfalfa and Stored Forage Conference

During the previous nineteen Kentucky Alfalfa Conferences, many topics pertaining to alfalfa have undoubtedly been addressed. In fact, some topics such as establishment techniques, varieties, and factors affecting yield are important enough that they have probably been discussed in one form or another during most of these conferences.

However, a twentieth-year state commodity conference is a milestone that deserves some special consideration, and which should justify inclusion of one or more unique topics on the program. This line of thinking led to idea that for this presentation it might be interesting to discuss some facts about alfalfa that are not …


Reducing Alfalfa Harvesting Losses, Michael Collins Feb 2000

Reducing Alfalfa Harvesting Losses, Michael Collins

Kentucky Alfalfa and Stored Forage Conference

In some areas of the country, producers store a substantial portion of their forage for winter feeding as silage or haylage. However, hay remains the most popular storage method for forage. Hay stores well for long periods and is better suited to cash sale and transportation than silage. Mechanical conditioning, which gained acceptance during the 1950's is probably still the greatest single change in hay harvesting and storage technology during this century. However, a number of other noteworthy changes and innovations have occurred in recent years which have helped to reduce the extent of losses during hay harvesting and storage.


Opportunities For Alfalfa As A Grazing Crop In Kentucky, Ken Johnson Feb 2000

Opportunities For Alfalfa As A Grazing Crop In Kentucky, Ken Johnson

Kentucky Alfalfa and Stored Forage Conference

Why do we continue to hear people talk about Alfalfa as a grazing crop? In my opinion there are two words that come to mind when I think of grazing Alfalfa, quality and yield. Alfalfa is without a doubt the highest quality forage we can graze. Alfalfa is also one of the highest yielding forages we can graze and maybe the highest yielding widely known and widely grown forage available to Kentucky farmers.


Hay Testing And New Marketing Program, Allen Johnson Feb 2000

Hay Testing And New Marketing Program, Allen Johnson

Kentucky Alfalfa and Stored Forage Conference

The Kentucky Department of Agriculture (Hay & Grain Branch) Hay testing program is now entering its 13th year of testing hay for Kentucky producers. The Department continues to use NIR forage analysis equipment. The program has made many improvements and much information has been gained. We continue to strive for quality control and producing accurate results. Recently, many new updates have occurred. New hardware and software have been added, along with the recent purchase of a second hay testing van. By placing a toll free call (1-800- 248-4628) to the Department of Agriculture in Frankfort, we will find a …


An Alfalfa Disease Calendar, Paul Vincelli Feb 2000

An Alfalfa Disease Calendar, Paul Vincelli

Kentucky Alfalfa and Stored Forage Conference

The following calendar provides producers and agricultural professionals with insights that may improve alfalfa production in several ways. First, knowing when to expect certain diseases improves one's ability to diagnose disease problems, which is a fundamental foundation for disease management. The many UK Extension Service publications on alfalfa as well as publications like the Alfalfa Analyst and the Compendium of Alfalfa Diseases, all are useful for diagnosis, but none provides a precise calendar of when to expect activity of alfalfa diseases in Kentucky. An alfalfa disease calendar can also provide occasional insights into timely management practices. For example, being …


Fertilizing Alfalfa For Profit, Monroe Rasnake, Steven G. Isaacs Feb 2000

Fertilizing Alfalfa For Profit, Monroe Rasnake, Steven G. Isaacs

Kentucky Alfalfa and Stored Forage Conference

Alfalfa has the potential for producing high yields of high quality forage with good management. A key component of good management is supplying plant nutrients in adequate quantities and proper balance. In Kentucky, this requires fertilizing soils with agricultural limestone, commercial fertilizers and/or animal manures. Good soil fertility is necessary for alfalfa stand establishment, high yields and long stand life.


Kentucky Alfalfa Conference After Twenty Years, Garry D. Lacefield Feb 2000

Kentucky Alfalfa Conference After Twenty Years, Garry D. Lacefield

Kentucky Alfalfa and Stored Forage Conference

Today marks the 20th consecutive year we have come together for a full days conference featuring "Alfalfa- Queen of the Forages" as the theme and focal point. Only one other state in the U.S. has such an annual event.


Foreword [2000], Garry D. Lacefield Feb 2000

Foreword [2000], Garry D. Lacefield

Kentucky Alfalfa and Stored Forage Conference

This is the front matter of the proceedings.


1999 Kentucky River Watershed Watch Data Collection Effort, L. Ormsbee, E. Caudill, G. Epp Feb 2000

1999 Kentucky River Watershed Watch Data Collection Effort, L. Ormsbee, E. Caudill, G. Epp

Kentucky River Watershed Watch

No abstract provided.


Effect Of Magnesium And Sulfur Fertilization Of Alfalfa, Kenneth L. Wells, James E. Dollarhide Jan 2000

Effect Of Magnesium And Sulfur Fertilization Of Alfalfa, Kenneth L. Wells, James E. Dollarhide

Soil Science News and Views

In response to concerns that high yields of alfalfa need to be fertilized with sulfur (S) because of soil depletion of S and less S entering the soil from atmospheric fallout, studies were conducted during 1998-1999, to test for S response by alfalfa. Additionally, alfalfa was tested for magnesium (Mg) response because previous hay analysis from the study site had shown very low levels of Mg.


Irrigated Field Crop Acres In Kentucky, Lloyd W. Murdock Jan 2000

Irrigated Field Crop Acres In Kentucky, Lloyd W. Murdock

Soil Science News and Views

Irrigation in Kentucky has always been limited. This is due to a limited water supply in many parts of Kentucky and the high amount of rainfall in the state which reduces the chances for a consistent profitable response to field crops.


Soil Testing For Agronomic And Environmental Uses, William O. Thom, Frank J. Sikora Jan 2000

Soil Testing For Agronomic And Environmental Uses, William O. Thom, Frank J. Sikora

Soil Science News and Views

Soil testing is a program that includes taking samples from a field or site, performing a laboratory analysis, and making recommendations for lime and crop nutrients. Good results from this program depend on several supporting factors: (I) obtaining samples representative of the soil in a field area or site; (2) using good techniques in the laboratory that give accurate indications of the nutrient status of the sampled area; and (3) having an extensive data base for making lime and nutrient recommendations from the analytical results.


Drawdown Of Soil Test Phosphorus And Potassium Levels By Alfalfa, Kenneth L. Wells, James E. Dollarhide Jan 2000

Drawdown Of Soil Test Phosphorus And Potassium Levels By Alfalfa, Kenneth L. Wells, James E. Dollarhide

Soil Science News and Views

Alfalfa hay production removes large amounts of phosphorus (P) and potassium (K) from soils. Because of this, there is always interest in the reduction of soil test phosphorus (STP) and soil test potassium (STK) levels by high-yielding alfalfa. Periodic soil sampling for 2 years during an on-farm· fertilizer study on a high yielding alfalfa field provided an insight into this.


Evaporation Reduction Potential In An Undisturbed Soil Irrigated With Surface Drip And Sand Tube Irrigation, Masoud Meshkat, Richard C. Warner, Stephen R. Workman Jan 2000

Evaporation Reduction Potential In An Undisturbed Soil Irrigated With Surface Drip And Sand Tube Irrigation, Masoud Meshkat, Richard C. Warner, Stephen R. Workman

Biosystems and Agricultural Engineering Faculty Publications

The efficiency of drip irrigation is highly dependent on evaporation losses occurring from the constantly saturated soil beneath emitters. Advent of subsurface drip irrigation is in part an approach to curb this inefficiency. An irrigation method, Sand Tube Irrigation (STI), is proposed to increase the efficiency of “Normal” surface applied drip Irrigation (NI method) on permanent tree crops without the need for burying the irrigation tubing. The sand tube consists of removing a soil core beneath the emitter and filling the void with coarse sand. A weighing lysimeter was constructed in the laboratory and instrumented to directly measure temporal evaporation …


Overview Of Environmental Regulations That Affect Coal Combustion, Cortland F. Eble Jan 2000

Overview Of Environmental Regulations That Affect Coal Combustion, Cortland F. Eble

Information Circular--KGS

Environmental regulations have had, and continue to have, an effect on the combustion of coal. These regulations largely affect the electric utility industry, the largest consumer of domestic coal, but they ultimately affect everyone, because we all use electricity, and the cost of compliance is usually passed on to the consumer, resulting in higher electric bills.


Coal Resources Of The Lower Elkhorn Coal Bed In Eastern Kentucky, Ernest E. Thacker, Gerald A. Weisenfluh, William M. Andrews Jr., John K. Hiett Jan 2000

Coal Resources Of The Lower Elkhorn Coal Bed In Eastern Kentucky, Ernest E. Thacker, Gerald A. Weisenfluh, William M. Andrews Jr., John K. Hiett

Map and Chart--KGS

This chart is one of a series that shows the regional characteristics of the Lower Elkhorn coal. The maps were prepared as part of the U.S. Geological Survey's Natural Coal Assessment Program, which compiles regional maps and databases that provide a comprehensive assessment of the most important coal beds in the nation. The Lower Elkhorn coal is one of the leading producers in the state of Kentucky and has, in some areas, a reputation as an excellent metallurgical-grade coal. It is known locally as the Pond Creek, Imboden, Path Fork, Blue Gem, Straight Creek, Bruin or Vires coal bed. This …