Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

University of Arkansas, Fayetteville

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1741 - 1770 of 2433

Full-Text Articles in Physical Sciences and Mathematics

Studies Of Zeolite Entrapped Ruthenium Polypyridine Complexes, Anwar A. Bhuiyan Jan 2005

Studies Of Zeolite Entrapped Ruthenium Polypyridine Complexes, Anwar A. Bhuiyan

Journal of the Arkansas Academy of Science

There is an intense interest in designing molecular systems which will absorb visible sunlight, initiate an electron transfer process, and ultimately convert the solar energy to useful chemical energy of fuels such as hydrogen produced from water. The zeolite-entrapped polypyridine complexes of divalent ruthenium hold promise as efficient photocatalysts for net charge separation and such efficiencies are further enhanced by organized incorporation of donor and acceptor components. This paper deals with the synthesis and spectroscopic investigation of zeolite-entrapped ruthenium polypyridine complexes which may be useful in the development of solar energy conversion schemes. The sensitizer molecules, such as Ru(bpy)3 2+ …

Go to article

Quantification And Prediction Of Stream Dryness In The Interior Highlands, Justin M. Homan, Nicholas M. Girondo, Charles J. Gagen Jan 2005

Quantification And Prediction Of Stream Dryness In The Interior Highlands, Justin M. Homan, Nicholas M. Girondo, Charles J. Gagen

Journal of the Arkansas Academy of Science

Although ecological studies have noted streams drying in the Interior Highlands, published measurements of streambed dryness are lacking. Clearly, stream drying has the potential to affect benthic macroinvertebrate and fish communities. In 2003, we initiated an assessment of streambed dryness for three streams in the Ouachita Mountains representative of the Central Hills, Ridges, and Valleys. In the following summer, we applied the approach to 15 similar size watersheds in three distinct ecoregions of the Interior Highlands: Ouachita Mountains-Athens Plateau, Ozark Highlands-Springfield Plateau, and Lower Boston Mountains. Repeated dryness measurements were recorded in each stream and correlated to nearby USGS stream …

Go to article

Identifying The Factors Distinguishing Timber Sales On Industrial And Non-Industrial Private Forest Lands In Arkansas, Sayeed R. Mehmood, Prabudhda Dahal Jan 2005

Identifying The Factors Distinguishing Timber Sales On Industrial And Non-Industrial Private Forest Lands In Arkansas, Sayeed R. Mehmood, Prabudhda Dahal

Journal of the Arkansas Academy of Science

Although forests provide a wide variety of products and services, timber still continues to be the most valued forest product in the marketplace. More than two-third of the nation's forests are under private control, some are owned by industries (about 10%) while a much larger portion (about 59%) is owned by individuals. This study investigates the differences between timber sales offered by industrial and non-industrial ownerships. A test of means revealed that there is a significant difference between per hectare bid for these 2 types of sales. A logistic regression model was then estimated to identify important factors characterizing this …

Go to article

Where Does It All End? Boundaries Beyond Euclidean Space, Jonathan Thompson Jan 2005

Where Does It All End? Boundaries Beyond Euclidean Space, Jonathan Thompson

Inquiry: The University of Arkansas Undergraduate Research Journal

No abstract provided.

Go to article

Water Quality Monitoring Of Moores Creek Above Lincoln Lake 2003, Marc A. Nelson, L. Wade Cash, G. Keith Trost Sep 2004

Water Quality Monitoring Of Moores Creek Above Lincoln Lake 2003, Marc A. Nelson, L. Wade Cash, G. Keith Trost

Technical Reports

No abstract provided.

Go to article

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Washington County Road 76 Bridge On Ballard Creek, Marc A. Nelson, L. Wade Cash, G. Keith Trost Sep 2004

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Washington County Road 76 Bridge On Ballard Creek, Marc A. Nelson, L. Wade Cash, G. Keith Trost

Technical Reports

The Illinois River Basin has experienced water quality impairment from non-point source pollution for many years. This fact was well documented in the State of Arkansas' Water Quality Assessment report, the Soil Conservation Service River Basin Study, and several University of Arkansas, Fayetteville studies. Thirty-seven sub-watersheds have been identified by the SCS in the Arkansas portion of the Illinois River basin. In the Arkansas portion of the Basin, the Illinois River, Evansville Creek, Baron Fork, Cincinnati Creek, Muddy Fork, Moores Creek, Clear Creek, Osage Creek and Flint Creek were all classified as not supporting their designated use as primary contact …

Go to article

2003 Pollutant Loads Kings River Near Berryville, Arkansas, Marc A. Nelson, L. Wade Cash Sep 2004

2003 Pollutant Loads Kings River Near Berryville, Arkansas, Marc A. Nelson, L. Wade Cash

Technical Reports

An automatic sampler and a USGS gauging station were established in 1998 and water quality sampling was begun in 1999 on the Kings River near Berryville, Arkansas. Continuous stage and discharge measurements and frequent water quality sampling have been used to determine pollutant concentrations and loads in the river. This report presents the results from the sampling and analysis for January 1, 2003 to December 31, 2003.

Go to article

Illinois River 2003 Pollutant Loads At Arkansas Highway 59 Bridge, Marc A. Nelson, L. Wade Cash Sep 2004

Illinois River 2003 Pollutant Loads At Arkansas Highway 59 Bridge, Marc A. Nelson, L. Wade Cash

Technical Reports

Automatic water samplers and a U. S. Geological Survey gauging station were established in 1995 on the main stem of the Illinois River at the Arkansas Highway 59 Bridge. Since that time, continuous stage and discharge measurements and water quality sampling have been used to determine pollutant concentrations and loads in the Arkansas portion of the Illinois River. This report represents the results from the measurement and sampling by the Arkansas Water Resources Center -Water Quality Lab for January 1, 2003 to December 31, 2003.

Go to article

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Washigton County Road 195 Bridge On The West Fork Of The White River 2003 Annual Report, Marc Nelson, L. Wade Cash, Sandi Formica Jul 2004

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Washigton County Road 195 Bridge On The West Fork Of The White River 2003 Annual Report, Marc Nelson, L. Wade Cash, Sandi Formica

Technical Reports

A water quality sampling station was installed at the Washington County road 195 bridge on the West Fork of the White River just above the confluence of the three main forks of the Upper White River in December 2001. The Quality Assurance Project Plan (QAPP) was approved by EPA Region six on March 2002 and sampling was begun at that time. This station is coordinated with a USGS gauging station at the same location. This station was instrumented to collect samples at sufficient intervals across the hydrograph to accurately estimate the flux of total suspended solids, nitrogen and phosphorus into …

Go to article

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Wyman Bridge On The White River, Marc Nelson, L. Wade Cash Jul 2004

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Wyman Bridge On The White River, Marc Nelson, L. Wade Cash

Technical Reports

An automatic water sampler was established in 2000 on the main stem of the White River at the Wyman Road Bridge. The Quality Assurance Project Plan (QAPP) was approved by EPA Region six on April 2000 and sampling was begun at that time. This station is coordinated with a USGS gauging station at the same location. This station was instrumented to collect samples at sufficient intervals across the hydrograph to accurately estimate the flux of total suspended solids, nitrogen and phosphorus into the upper end of Beaver Lake from the White River. The Upper White was designated as the states …

Go to article

Comparison Of Dissolved And Acid-Extractable Metal Concentrations In Groundwater, Eastern Arkansas, Burmshik Kim, Kenneth F. Steele, Todd Fugitt Jan 2004

Comparison Of Dissolved And Acid-Extractable Metal Concentrations In Groundwater, Eastern Arkansas, Burmshik Kim, Kenneth F. Steele, Todd Fugitt

Journal of the Arkansas Academy of Science

No abstract provided.

Go to article

Be Star Spectroscopy Using The Uca Fiber-Fed Spectrograph, Scott Austin Jan 2004

Be Star Spectroscopy Using The Uca Fiber-Fed Spectrograph, Scott Austin

Journal of the Arkansas Academy of Science

Beginning in June 2003, undergraduate students and the author have spectroscopically monitored bright Be stars using a custom built fiber-fed spectrograph attached to the UCA Observatory 11-inch Schmidt-Cassegrain telescope. We have obtained 0.8 Angstrom/pixel resolution spectra of the H-alpha line for over forty Be-Stars. Some have been observed on multiple dates in order to detect any temporal changes. Line profiles, velocities, and observed variations for some of these stars will be presented.

Go to article

Electric Discharge: Boundary Conditions, Mostafa Hemmati, Chris Justice Jan 2004

Electric Discharge: Boundary Conditions, Mostafa Hemmati, Chris Justice

Journal of the Arkansas Academy of Science

The electron gas in electric discharge can be described by a set of one-dimensional fluid dynamical equations. The fundamental equations are those of a three-component (electrons, ions, and neutral particles) fluid, different from the treatment of the problem inplasma physics, a fully ionized two-component case. The leading edge of the wave is treated as a shock front driven mainly by the electron gas pressure. Integrating the one-dimensional global differential equations for mass balance, conservation of momentum and energy, and evaluating the constant of integration at the wave front permits derivation of boundary conditions on electron temperature and electron velocity. Using …

Go to article

Impact Of Black Shale Weathering On Sediment Quality, G. M. Ogendi, R. E. Hannigan, Jerry L. Farris, D. Smith Jan 2004

Impact Of Black Shale Weathering On Sediment Quality, G. M. Ogendi, R. E. Hannigan, Jerry L. Farris, D. Smith

Journal of the Arkansas Academy of Science

Weathering of black shales leads to elevated metal concentrations in both surface water and stream sediments. In spite of the recent focus on black shales, few data exist on the ecological impacts of this process particularly on aquatic organisms. The key objective of this study was to determine the impact of trace metal concentrations in sediments upon aquatic organisms. To achieve the above objective, stream sediment samples were collected from streams draining black shale and limestone (used as a reference stream) lithologies located in central Arkansas between June 2003 and January 2004. Trace metal concentrations were measured by the dynamic …

Go to article

The Effects Of Multiple Mutations In The Hydrophobic Core Upon The Stability Of Staphylococcal Nuclease, Rebecca L. Danforth Jan 2004

The Effects Of Multiple Mutations In The Hydrophobic Core Upon The Stability Of Staphylococcal Nuclease, Rebecca L. Danforth

Inquiry: The University of Arkansas Undergraduate Research Journal

Previous work in the laboratory of my research advisor, Dr. Wesley Stites, has investigated the core packing of the protein staphylococcal nuclease. The core of a protein is critical in determining a protein's structure and stability. The hydrophobicity of the core has long been thought to be the principal driving force for folding, but recent work in the Stites lab has shown that optimization of van der Waals contacts and minimization of cavities, in our shorthand term, packing, is at least as energetically important. We are building upon this information in our attempt to better pack the protein core. If …

Go to article

Tailwater Recovery Systems For Irrigation: Benefit/Cost Analysis And Water Resource Conservation Technique In Northeast Arkansas, Jennifer L. Bouldin, Nate A. Bickford, H. B. Stroud, G. S. Guha Jan 2004

Tailwater Recovery Systems For Irrigation: Benefit/Cost Analysis And Water Resource Conservation Technique In Northeast Arkansas, Jennifer L. Bouldin, Nate A. Bickford, H. B. Stroud, G. S. Guha

Journal of the Arkansas Academy of Science

Water, one of the earth's most vital resources, is particularly significant in the Arkansas Delta agricultural landscape. While both surface and groundwater are extremely important, 94% of the 26.9 billion L (7.1 billion gal) of water pumped daily from the Alluvial Aquifer is used for agricultural purposes. This common property is subsequently being depleted and sustainable conservation methods are being pursued. State and federal incentive programs encourage the use of a tailwater recovery system in agricultural irrigation. With the use of a complete recovery system, benefits include not only government incentives for wetland habitat, but reduced groundwater use and decreased …

Go to article

Effects Of Vegetation Removal On Native Soil Quality In Eastern Arkansas, Lorena Moreno, Kristofor R. Brye Jan 2004

Effects Of Vegetation Removal On Native Soil Quality In Eastern Arkansas, Lorena Moreno, Kristofor R. Brye

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Aboveground vegetation removal practices, such as cutting and baling and burning, can both positively and negatively affect a prairie ecosystem. Burning can stimulate growth and species diversity, but removing vegetation and the nutrients it contains without equal replenishment of those nutrients could cause a steady decline in available soil nutrients. The objective of this study was to evaluate the effects of vegetation removal techniques in a native tallgrass prairie in eastcentral Arkansas. Soil samples were collected from the top 10 cm in each soil mapping unit that existed in each of three prairie areas that differed by the amount of …

Go to article

Assessment And Restoration Of A Neighborhood Wetland Invaded By Exotic Plant Species, Ryan Neal, Kimberly R. Payne, Lorena Moreno, Graham Duffy, Jonathan Peck, Mary C. Savin Jan 2004

Assessment And Restoration Of A Neighborhood Wetland Invaded By Exotic Plant Species, Ryan Neal, Kimberly R. Payne, Lorena Moreno, Graham Duffy, Jonathan Peck, Mary C. Savin

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

The University of Arkansas Crop, Soil, and Environmental Sciences (CSES) Club adopted a local wetland in the spring of 2002 through the Fayetteville Parks and Recreation Department. This project has allowed students to interact with local community and governmental organizations as well as other academic departments within the university. Students have gained valuable laboratory and field experience through characterizing hydric soils, identifying bird and plant species, and analyzing water quality, soil nutrients, and microbial biomass. Under the main goal of restoring the wetland, the club has outlined both short and long-term objectives including soil and water assessments; removal of two …

Go to article

Characterizing Bean Pod Rot In Arkansas And Missouri, Jeremy H. Taylor, Craig S. Rothrock Jan 2004

Characterizing Bean Pod Rot In Arkansas And Missouri, Jeremy H. Taylor, Craig S. Rothrock

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Green beans are an important crop grown for processing in both Arkansas and Missouri. Green beans are harvested mechanically using non-selective picking fingers. Harvested beans are then transported in bulk to processing plants that are located at various locations throughout the midSouth. Thus, the crop is managed for high quality, avoiding pod blemishes caused by insects and diseases. One of the consistent quality problems that affect Arkansas and Missouri green bean crops is pod rot. Two of the causal agents of pod rot that have been reported by researchers and vegetable companies alike are Pythium aphanidermatum and an unidentified Phytophthora …

Go to article

Method Analysis Of Laboratory Measures Of Stream Sediment And Water Phosphorus Equilibrium, Anna L. Erickson, Stephanie M. Williamson, Brian E. Haggard Jan 2004

Method Analysis Of Laboratory Measures Of Stream Sediment And Water Phosphorus Equilibrium, Anna L. Erickson, Stephanie M. Williamson, Brian E. Haggard

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Elevated phosphorus concentrations in aquatic ecosystems of northwest Arkansas prompted an investigation of the effects of sample preparation and extraction methods on laboratory measures of sediment-phosphorus interactions. Two streams of contrasting phosphorus (P) concentrations were selected to determine the effect of using a CaCl2 solution instead of filtered stream water, refrigerated or dried sediments instead of fresh wet sediments, and vortexing the suspensions instead of shaking them. Sediment equilibrium P concentration (EPC0) and P buffering capacity (K) were used to determine differences in extraction methods. EPC0 and K from extractions using fresh sediments and a CaCl2 solution matching the electrical …

Go to article

Laboratory-Scale Evaluation Of Incandescent And Compact Florescent Lamps For Poultry House Lighting, Leanne Gabriel, Donald M. Johnson Jan 2004

Laboratory-Scale Evaluation Of Incandescent And Compact Florescent Lamps For Poultry House Lighting, Leanne Gabriel, Donald M. Johnson

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

This laboratory-scale study compared 1000- and 2000-h rated 60W incandescent lamps and 6000-h rated 60W-equivalent compact florescent lamps over 6000 h of simulated broiler-house operation. The four original 1000-h incandescent lamps were replaced 22 times and the four 2000-h incandescent lamps were replaced 14 times. None of the four compact florescent lamps failed during the 6000-h experiment, although one was broken due to human error. Both types of incandescent lamps had significantly higher (p < .0001) mean illuminance (lx) than did the compact florescent lamps. The compact florescent lamps used significantly less (p < .0001) power (W) and had significantly higher (p < .0001) efficiency (lx/W) than the incandescent lamps. Despite a higher initial purchase price, the total cost (purchase + replacement + electrical) of operating compact florescent lamps was approximately 36% lower than the total cost of operating either type of incandescent lamp over the 6000 h period. The results of this study indicate that even at a least-cost price for electricity ($0.04/kW/h), growers can reduce total broilerhouse lighting costs by replacing incandescent lamps with compact florescent lamps.

Go to article

Swine Waste Demonstration And Training Project, C. V. Maxwell, K. Vandevender, K. P. Coffey, P. A. Moore, I. Chaubey, D. R. Smith Dec 2003

Swine Waste Demonstration And Training Project, C. V. Maxwell, K. Vandevender, K. P. Coffey, P. A. Moore, I. Chaubey, D. R. Smith

Technical Reports

No abstract provided.

Go to article

Water Quality Monitoring Of Moore's Creek Above Lincoln Lake, M. A. Nelson, L. W. Cash, G. K. Trost Nov 2003

Water Quality Monitoring Of Moore's Creek Above Lincoln Lake, M. A. Nelson, L. W. Cash, G. K. Trost

Technical Reports

No abstract provided.

Go to article

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Washington County Road 76 Bridge On Ballard Creek, Marc A. Nelson, Ron Redman, L. Wade Cash, G. Keith Trost Nov 2003

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Washington County Road 76 Bridge On Ballard Creek, Marc A. Nelson, Ron Redman, L. Wade Cash, G. Keith Trost

Technical Reports

The Illinois River Basin has experienced water quality impairment from non-point source pollution for many years. This fact was well documented in the State of Arkansas' Water Quality Assessment report, the Soil Conservation Service River Basin Study, and several University of Arkansas, Fayetteville studies. Thirty-seven sub-watersheds have been identified by the SCS in the Arkansas portion of the Illinois River basin. In the Arkansas portion of the Basin, the Illinois River, Evansville Creek, Baron Fork, Cincinnati Creek, Muddy Fork, Moores Creek, Clear Creek, Osage Creek and Flint Creek were all classified as not supporting their designated use as primary contact …

Go to article

2002 Pollutant Loads Kings River Near Berryville, Arkansas, Marc Nelson, Wade Cash Nov 2003

2002 Pollutant Loads Kings River Near Berryville, Arkansas, Marc Nelson, Wade Cash

Technical Reports

An automatic sampler and a USGS gauging station were established in 1998 and water quality sampling was begun in 1999 on the Kings River near Berryville, Arkansas. Continuous stage and discharge measurements and frequent water quality sampling have been used to determine pollutant concentrations and loads in the river. This report presents the results from the sampling and analysis for January 1, 2002 to December 31, 2002.

Go to article

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Washington County Road 195 Bridge On The West Fork Of The White River, Marc Nelson, Wade Cash Nov 2003

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Washington County Road 195 Bridge On The West Fork Of The White River, Marc Nelson, Wade Cash

Technical Reports

A water quality sampling station was installed at the Washington County Road 195 Bridge on the West Fork of the White River just above the confluence of the three main forks of the Upper White River in December 2001. The Quality Assurance Project Plan (QAPP) was approved by EPA Region Six on March 2002 and sampling was begun at that time. This station is coordinated with a USGS gauging station at the same location. This station was instrumented to collect samples at sufficient intervals across the hydrograph to accurately estimate the flux of total suspended solids, nitrogen and phosphorus into …

Go to article

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Wyman Road Bridge On The White River, Marc Nelson, Wade Cash Nov 2003

Water Quality Sampling, Analysis And Annual Load Determinations For Tss, Nitrogen And Phosphorus At The Wyman Road Bridge On The White River, Marc Nelson, Wade Cash

Technical Reports

A water quality sampling station was installed at the Wyman Road Bridge just below the confluence of the three main forks of the Upper White River in January 2000. This station is coordinated with the USGS gaging station at the same location. This station was instrumented to collect samples at sufficient intervals across the hydrograph to accurately estimate the flux of total suspended solids, nitrogen and phosphorus into the upper end of Beaver Lake from the Upper White River.

Go to article

Illinois River 2002 Pollutant Loads At Arkansas Highway 59 Bridge, Marc A. Nelson, Wade Cash Sep 2003

Illinois River 2002 Pollutant Loads At Arkansas Highway 59 Bridge, Marc A. Nelson, Wade Cash

Technical Reports

Automatic water samplers and a U. S. Geological Survey gauging station were established in 1995 on the main stem of the Illinois River at the Arkansas Highway 59 Bridge. Since that time, continuous stage and discharge measurements and water quality sampling have been used to determine pollutant concentrations and loads in the Arkansas portion of the Illinois River. This report represents the results from the measurement and sampling by the Arkansas Water Resources Center -Water Quality Lab for January 1, 2002 to December 31, 2002.

Go to article

Stormwater Pollution Prevention Bmp Workshop, Demonstration, And Evaluation, Findlay G. Edwards Jun 2003

Stormwater Pollution Prevention Bmp Workshop, Demonstration, And Evaluation, Findlay G. Edwards

Technical Reports

With the recent promulgation of Phase II of the National Pollution Discharge Elimination System (NPDES) Stormwater Pollution Control regulations, many construction companies, consulting engineers, architects, and regulating agency personnel are unaware of the new stormwater pollution reduction requirements. In addition, they are typically unaware of Best Management Practices (BMPs) that are available to mitigate stormwater discharge pollution and the proper methods of installing and maintaining BMPs. The Water Quality Goals and Objectives were to train engineers, contractors, architects, and governmental officials on the new Phase II Storm Water NPDES regulations and Best Management Practices available for construction projects. The Original …

Go to article

Bioassessment Of The West Fork Of The White River, Northwest Arkansas, Arthur V. Brown, Andrea J. Radwell, Robin A. Reese Jun 2003

Bioassessment Of The West Fork Of The White River, Northwest Arkansas, Arthur V. Brown, Andrea J. Radwell, Robin A. Reese

Technical Reports

The West Fork-White River has been and continues to be an important water resource for northwest Arkansas. It is used recreationally for fishing and swimming, agriculturally as a source of water for livestock and irrigation of crops, it is mined for gravel, used as a receiving stream for municipal wastewater effluent, and contributes to Beaver Lake which provides water for treatment and distribution to most of northwest Arkansas. While these uses have benefited a large segment of the Arkansas population, they have also contributed to the decline in environmental quality of the river. To facilitate the development of appropriate management …

Go to article

First Prev Next Last