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Articles 1801 - 1830 of 2433

Full-Text Articles in Physical Sciences and Mathematics

Electrostatic Microencapsulation Of Composite Particulate Materials For Manufacturing And Environmental Applications, S. De, M. Pritchett, Malay K. Mazumder, Robert A. Sims, C. U. Yurteri, Alexandru S. Biris, A. Rego Jan 2002

Electrostatic Microencapsulation Of Composite Particulate Materials For Manufacturing And Environmental Applications, S. De, M. Pritchett, Malay K. Mazumder, Robert A. Sims, C. U. Yurteri, Alexandru S. Biris, A. Rego

Journal of the Arkansas Academy of Science

Electrostatic microencapsulation is a dry coating process where two powders, one containing the fines and the other relatively larger particles, are separately dispersed in air and pre-charged with opposite polarity, using corona charging for electrostatic coagulation. These oppositely charged core and guest particles experience attractive electrostatic forces and generate composite particles. Preliminary experiments of electrostatic microencapsulation were performed using Anionic Exchange Resin (AG 1-X8) as the host particle and Red Toner (Omega 4000) as the guest particles. An electrostatic microencapsulation tower has been designed for generation of composite particles using particles of different particle size distribution.

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Alumina And Synthesis Intermediates Derived From Diethylkaluminum Amide, Benzaldehyde And Water, Stephen E. Hall, Lize Wilcox, William S. Tyree, David A. Lindquist, Malay K. Mazumder Jan 2002

Alumina And Synthesis Intermediates Derived From Diethylkaluminum Amide, Benzaldehyde And Water, Stephen E. Hall, Lize Wilcox, William S. Tyree, David A. Lindquist, Malay K. Mazumder

Journal of the Arkansas Academy of Science

The reaction of diethylaluminum amide [Et2AINH2] with benzaldehyde in toluene produces a solution of ethylaluminoxane polymer [EtAlO] and hydrobenzamide [PhCH=NCH(Ph)N=CHPh]. Alumina then is precipitated by the addition of water. Transition aluminas that may be useful in heterogeneous catalyst applications are obtained after calcining. Details of the chemistry of solution intermediates according to 1H NMR and the properties of the alumina product according to surface area analyses and powder x-ray diffraction are described.

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Bedrock Geology Of West Fork Quadrangle, Washington County, Arkansas, Jack T. King, Maria E. King, Stephen K. Boss Jan 2002

Bedrock Geology Of West Fork Quadrangle, Washington County, Arkansas, Jack T. King, Maria E. King, Stephen K. Boss

Journal of the Arkansas Academy of Science

A digital geologic map of West Fork quadrangle was produced at 1:24,000 scale using the geographic information system (GIS) software Maplnfo. Data regarding stratigraphic relations observed in the field were digitized onto the United States Geological Survey (USGS) digital raster graphic (DRG) of West Fork quadrangle. The geology of West Fork quadrangle consists of sedimentary rocks of the Mississippian and Pennsylvanian systems. The Fayetteville Shale and Pitkin Formation represent the Mississippian system. The Hale, Bloyd, and Atoka Formations represent the Pennsylvanian System. Each of these formations consists of members that were mapped at 1:24,000 scale, and this mapping effort represents …

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Chemical Composition Of Particles Of D < 0.20 Mu In The Lower Stratospheric Aerosol, Spring 1993, Joseph D. Scott, David M. Chittenden Ii Jan 2002

Chemical Composition Of Particles Of D < 0.20 Mu In The Lower Stratospheric Aerosol, Spring 1993, Joseph D. Scott, David M. Chittenden Ii

Journal of the Arkansas Academy of Science

The majority of the mass of stratospheric aerosol collected during the spring of 1993 consisted principally of particles of d >0.20 mu containing a mixture of H2SO4 and (NaK)2SO4. However, the composition of the more numerous particles with d< 0.2 mu was very different. X-ray emission spectra (EDS) of individual particles indicated that there were three different chemical populations of small particles. The most numerous population was almost all C with only traces of S and Na. The second population contained metal sulfates and chlorides, possibly accreted to a C-containing matrix. The third population consisted of S- and Cl- containing species and trace amounts of Na and K ions. The number of equivalents of metal ion was much less than that of S and Cl species, indicating that most of the S and Cl was not ionic, but was covalently bonded, perhaps to a C matrix.

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Quantification Of Land-Use Impact On Stream Water Quality, Scott Dennis, Indrajeet Chaubey, Brian Haggard Jan 2002

Quantification Of Land-Use Impact On Stream Water Quality, Scott Dennis, Indrajeet Chaubey, Brian Haggard

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

Accelerated eutrophication of Beaver Lake in northwest Arkansas is a major environmental concern. When developing watershed-management plans to protect lake water quality, it is important that linkages among land-use activities and water quality of tributary streams be quantified. This study assessed longitudinal base-flow and storm-flow water quality at War Eagle Creek and quantified linkages between stream water quality and land-use conditions within the War Eagle Creek sub-watershed of the Beaver Lake watershed. We collected six water samples: three from base-flow conditions and three from storm-flow conditions during Spring 2002. In general, concentrations of nitrate nitrogen (NO3-N), total N (TN), total …

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Land-Use Effects On Soil-Water Retention Characteristic, Naomi Colton, Kristofor Brye Jan 2002

Land-Use Effects On Soil-Water Retention Characteristic, Naomi Colton, Kristofor Brye

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

Tillage can negatively affect soil physical properties such as bulk density, organic matter content, and soil hydraulic properties, which in turn affect how plants grow. The objective of this study was to evaluate water retention characteristics of a Jay silt loam soil under cultivated agriculture and native tallgrass prairie in northwest Arkansas. Air-dry soil samples collected from 0-10 cm depth were re-wet with varying amounts of distilled water to create a range of water contents. After overnight equilibration, the water potential was measured on the re-wet soil samples using a dewpoint potentiameter. The relationship between water potential (Ψ) and water …

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Illinois River 2000 Pollutant Loads At Arkansas 59 Bridge, Marc A. Nelson, Thomas S. Soerens Oct 2001

Illinois River 2000 Pollutant Loads At Arkansas 59 Bridge, Marc A. Nelson, Thomas S. Soerens

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 for January 1, 2000 to December 31, 2000

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Application Of Neuro-Fuzzy Technique+2:9s To Predict Ground Water Vulnerability In Northwest Arkansas, B. Dixon, H. D. Scott, J. V. Brahana, A. Mauromoustakos Jul 2001

Application Of Neuro-Fuzzy Technique+2:9s To Predict Ground Water Vulnerability In Northwest Arkansas, B. Dixon, H. D. Scott, J. V. Brahana, A. Mauromoustakos

Technical Reports

Contamination of ground water has been a major concern in recent years of local, state and federal agencies involved with the management, quality, and quantity of water and their relationships with human health. The Springfield Plateau aquifer, which lies beneath the study area in northwest Arkansas, has been shown to have higher nitrate-N (NO3-N) concentrations than the national median. The dominant landuse (LULC) of this area is agriculture (primarily pasture/cattle and woodlands) and an encroaching urbanization. The major sources of nitrogen in the study area are poultry/cattle wastes, inorganic fertilizers (Peterson et. al., 1998) and septic filter fields. Many of …

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Protection Of Cave Spring Cave Biota And Groundwater Basin, G. O. Graening, A. V. Brown Jun 2001

Protection Of Cave Spring Cave Biota And Groundwater Basin, G. O. Graening, A. V. Brown

Technical Reports

This is the fourth in a series of reports on the status of endangered biota and of environmental quality in Cave Springs Cave (CSC), Benton County, Arkansas (Brown et al., 1998; Graening and Brown, 1999, 2000), funded by the Arkansas Natural Heritage Commission (ANHC). As a result of these studies, Cave Springs Cave is now one of the most thoroughly studied cave ecosystems in Arkansas. This series of studies has spawned a renewed interest in cave ecosystems and their vulnerable condition. There are now many projects focusing upon the documentation of subterranean biodiversity and its protection. Partners include the Arkansas …

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Addressing Uncertainty In Tmdls: Short Course At Arkansas Water Resources Center 2001 Annual Conference, Marty Matlock, Matthew Murawski Apr 2001

Addressing Uncertainty In Tmdls: Short Course At Arkansas Water Resources Center 2001 Annual Conference, Marty Matlock, Matthew Murawski

Technical Reports

Management of a critical natural resource like water requires information on the status of that resource. The US Environmental Protection Agency (EPA) reported in the 1998 National Water Quality Inventory that more than 291,000 miles of assessed rivers and streams and 5 million acres of lakes do not meet State water quality standards. This inventory represents a compilation of State assessments of 840,000 miles of rivers and 17.4 million acres of lakes; a 22 percent increase in river miles and 4 percent increase in lake acres over their 1996 reports. Siltation, bacteria, nutrients and metals were the leading pollutants of …

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Determination Of Nutrient Loads In Upper Moore's Creek 2000, M. A. Nelson, W. L. Cash, K. F. Steele Mar 2001

Determination Of Nutrient Loads In Upper Moore's Creek 2000, M. A. Nelson, W. L. Cash, K. F. Steele

Technical Reports

No abstract provided.

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Determination Of The Pollutant Loads In The Kings River Near Berryville, Thomas S. Soerens, Marc A. Nelson Mar 2001

Determination Of The Pollutant Loads In The Kings River Near Berryville, Thomas S. Soerens, Marc A. Nelson

Technical Reports

An automatic sampler and a U.S. Geological Swvey (USGS) gauging station were established in 1998 and water quality sampling was begun in 1999 on the Kings River near Benyville, Arkansas. Continuous stage and discharge measurements and frequent water quality sampling have been used to determine pollutant concentrations and loads in t11e river. In addition, ten samples were taken by Arkansas Water Resources Center (A WRC) concurrently with USGS samples in order to assess whether A WRC and USGS samples can be compared. This report presents the results from the sampling and analysis for January 1, I999 to December 31, 1999. …

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Demonstration Of Best Management Practices For The Protection And Improvement Of The Soil And Water Resources In The Arkansas Delta, M. A. Henslee, W. H. Baker, S. D. Carroll, J. L. Farris, S. D. Davis, C. D. Milam, J. L. Pierce Feb 2001

Demonstration Of Best Management Practices For The Protection And Improvement Of The Soil And Water Resources In The Arkansas Delta, M. A. Henslee, W. H. Baker, S. D. Carroll, J. L. Farris, S. D. Davis, C. D. Milam, J. L. Pierce

Technical Reports

This report is the compilation of a multi~year project that was directed at identifying the impact and possible mitigation solutions of non-point pollution from row crop agriculture in a watershed in the Arkansas Delta. The first part of the project involved an inventory of the condition of the major streams that make up the study watershed. The remainder of the project was focused at demonstrating and reporting best management nutrient and sediment runoff control practices (BMP) that could be implemented. The final assessment of the demonstration work is a GIS analysis that provides an overview of the effectiveness of these …

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Improvements In Turfgrass Color And Density Resulting From Comprehensive Soil Diagnostics, Matt Cordell, Jonathan Davis, David E. Longer Jan 2001

Improvements In Turfgrass Color And Density Resulting From Comprehensive Soil Diagnostics, Matt Cordell, Jonathan Davis, David E. Longer

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

There are roughly 220 golf courses in Arkansas, and as many as 50% of these courses were constructed using common bermudagrass fairways. Although resilient, common bermudagrass loses density and quality over time. In this experiment physical and chemical properties of the soil were analyzed to determine the causes of decline in turf quality observed on several fairways of a local golf course. Once a particular fairway was selected for study and preliminary soil sampling conducted, GS+, a geostatistical computer program, was used to map the location of certain chemical deficiencies. A moderate to severe Mg deficiency was detected throughout the …

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Uranium-Uranium Collisions At Relativistic Energies, Bao-An Li, Matt Tilley Jan 2001

Uranium-Uranium Collisions At Relativistic Energies, Bao-An Li, Matt Tilley

Journal of the Arkansas Academy of Science

No abstract provided.

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Non-Commercial Software For The Analysis And Interpretation Of High Resolution Molecular Spectra, A. R. Ford, Scott W. Reeve Jan 2001

Non-Commercial Software For The Analysis And Interpretation Of High Resolution Molecular Spectra, A. R. Ford, Scott W. Reeve

Journal of the Arkansas Academy of Science

No abstract provided.

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Synthesis And Characterization Of A Ruthenium-Thioxane Complex, Amanda Wroble, Scotty Sproles, Mark Draganjac, Paul M. Nave Jan 2001

Synthesis And Characterization Of A Ruthenium-Thioxane Complex, Amanda Wroble, Scotty Sproles, Mark Draganjac, Paul M. Nave

Journal of the Arkansas Academy of Science

No abstract provided.

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Life History Of The River Shiner, Notropis Blennius (Cyprinidae), In The Arkansas River Of Western Arkansas, Laura Hudson, Thomas M. Buchanan Jan 2001

Life History Of The River Shiner, Notropis Blennius (Cyprinidae), In The Arkansas River Of Western Arkansas, Laura Hudson, Thomas M. Buchanan

Journal of the Arkansas Academy of Science

The reproductive cycle, food habits, and age and growth of the river shiner, Notropis blennius (Girard), in the Arkansas River of western Arkansas were studied from May 1996 through October 1997. Based on gonadosomatic indices and mean ovumd iameters of females, tubercle development in males, and the first appearance of young-of-year in samples, the breeding season extended from June through August in both 1996 and 1997. The river shiner is a diurnal, generalist feeder that forages on a wide variety of food items. In all four seasons, detritus dominated the diets of adults and juveniles in terms of volume and …

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Synthesis Of A Ruthenium-Tetra(Tht)Dichloride Compound And The Molecular Structure Of The Partially Oxidized Compound Rucl2(Tht)2.2(Tht-O)1.8, L. A. Thornton, Mark Draganjac, Andres Meza, A. W. Cordes Jan 2001

Synthesis Of A Ruthenium-Tetra(Tht)Dichloride Compound And The Molecular Structure Of The Partially Oxidized Compound Rucl2(Tht)2.2(Tht-O)1.8, L. A. Thornton, Mark Draganjac, Andres Meza, A. W. Cordes

Journal of the Arkansas Academy of Science

No abstract provided.

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Multi-Phase Transport Study Of Relativistic Nuclear Collisions, Bin Zhang, C. M. Ko, Bao-An Li, Ziwei Lin, Subrata Pal Jan 2001

Multi-Phase Transport Study Of Relativistic Nuclear Collisions, Bin Zhang, C. M. Ko, Bao-An Li, Ziwei Lin, Subrata Pal

Journal of the Arkansas Academy of Science

A multi-phase transport model (AMPT) is developed for the study of hot and dense matter produced in relativistic nuclear collisions. This model includes both initial partonic and final hadronic scattering. Using the AMPT model, we study the momentum distributions of charged particles such as protons, antiprotons, pions, and kaons in central heavy ion collisions at Super Proton Synchrotron (SPS) and Relativistic Heavy Ion Collider (RHIC) energies. The results are consistent with experimental data at these energies. They indicate a significant nuclear shadowing but a relative weak jet quenching in the initial dense matter. Antiproton to proton ratio at mid-rapidity increases …

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Intractability And Undecidability In Small Sets Of Wang Tiles, Adam Delisse Jan 2001

Intractability And Undecidability In Small Sets Of Wang Tiles, Adam Delisse

Inquiry: The University of Arkansas Undergraduate Research Journal

Imagine a never-ending checkerboard, red and black squares alternating forever in every direction. Now close your eyes, wait for a second, and open them again. There is still the checkerboard, but is it different? Has somebody moved the checkerboard over two squares? Four squares? One million squares? It still looks the same. This is the nature of periodic tilings. Wang tiles are squares, much like the red and black ones used on a checkerboard, except Wang tiles have colors on their edges instead of on the whole square. Also, Wang tiles can only be put edge-to-edge with each other where …

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Bedrock Geology And Sea-Level History Of Fayetteville Quadrangle, Washington County, Arkansas, Maria E. King, Jack T. King, Stephen K. Boss Jan 2001

Bedrock Geology And Sea-Level History Of Fayetteville Quadrangle, Washington County, Arkansas, Maria E. King, Jack T. King, Stephen K. Boss

Journal of the Arkansas Academy of Science

A digital map depicting the detailed bedrock geology of Fayetteville Quadrangle, Washington County, Arkansas was produced at 1:24,000 scale. This map was developed utilizing state-of-the-art Geographic Information Systems technology and represents the most detailed map of the geology of Fayetteville Quadrangle that has been produced. In addition, the stratigraphy was interpreted to develop a regional sea-level history for the quadrangle. The bedrock geology of Fayetteville Quadrangle consists of sedimentary rocks of the Mississippian and Pennsylvanian systems. The Mississippian System is represented by (in ascending order) the Boone, Batesville, Fayetteville, and Pitkin Formations. The Pennsylvanian System is represented by (in ascending …

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Geologic Hazards Associated With Shale Strata And Swelling Clays Within Fayetteville Quadrangle, Washington County, Arkansas, Maria E. King, Jack T. King, Stephen K. Boss Jan 2001

Geologic Hazards Associated With Shale Strata And Swelling Clays Within Fayetteville Quadrangle, Washington County, Arkansas, Maria E. King, Jack T. King, Stephen K. Boss

Journal of the Arkansas Academy of Science

No abstract provided.

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Thermodynamic Properties Of Neutron-Rich Matter, Matt Tilley, Bao-An Li Jan 2001

Thermodynamic Properties Of Neutron-Rich Matter, Matt Tilley, Bao-An Li

Journal of the Arkansas Academy of Science

The mechanism of supernova explosion and properties of neutron stars are uniquely determined by the equation of state of neutron-rich matter. Using a phenomenological equation of state within a thermal model, we study thermodynamic properties of neutron-rich matter. In particular, we investigate chemical (diffusive) and mechanical (isothermal) instabilities of neutron-rich matter and their dependence on the nuclear equation of state. Both instabilities are found to be heavily dependent upon the isospin asymmetry, temperature, and density of neutron-rich matter. We show that the boundary of the chemical instability extends farther out into the density-isospin symmetry plane than that of the mechanical …

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Moisture Determination By Thermal Titrimetry Using The Enthalpy Of Reaction Of 2,2-Dimethoxypropane With Water, Edmond W. Wilson Jr., Reagan Baber Jan 2001

Moisture Determination By Thermal Titrimetry Using The Enthalpy Of Reaction Of 2,2-Dimethoxypropane With Water, Edmond W. Wilson Jr., Reagan Baber

Journal of the Arkansas Academy of Science

Assays for water content can be readily and simply carried out using the technique of thermal titrations. The method is based on measuring the endothermic heat of reaction exhibited when 2,2-dimethoxypropane is brought into contact with water in the presence of an acid catalyst. The apparatus is simple, requiring a constant delivery rate buret, a recording thermistor thermometer, and a stirred, thermally insulated reaction container. The 2,2-dimethoxypropane reagent used for the water assays is environmentally friendly ("green"). It is stable, pleasant smelling and economical. Working curves in three solvents, acetonitrile, tetrahydrofuran and 1,4-dioxane, show excellent precision and linearity with increasing …

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Plasmid Analysis Of Bacteria That Metabolize The Detergent Igepon, Russell O. Nordeen, Thetsu Mon, David Gilmore Jan 2001

Plasmid Analysis Of Bacteria That Metabolize The Detergent Igepon, Russell O. Nordeen, Thetsu Mon, David Gilmore

Journal of the Arkansas Academy of Science

No abstract provided.

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Empirical Model For The Variarion In Concentration Of Metal Ions During A Precipitation Event, David M. Chittenden Ii, Julie D. Chittenden Jan 2001

Empirical Model For The Variarion In Concentration Of Metal Ions During A Precipitation Event, David M. Chittenden Ii, Julie D. Chittenden

Journal of the Arkansas Academy of Science

The concentration of a pollutant in an air mass and the concentration of that pollutant in a series of rain water samples from a single event within that air mass, fluctuate during the course of the event. This the result of scavenging, diffusion, and advection processes. A simple mathematical model, containing only a scavenging term has had limited success in describing changes of concentration in rain water. To date, no attempt has been made to include diffusion or advection terms in the model. In this study, a two factor model was developed after determining that (1) the exponential scavenging term …

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An Analysis Of Unsolvable Linear Partial Differential Equations Of Order One, Laura J. Fields Jan 2001

An Analysis Of Unsolvable Linear Partial Differential Equations Of Order One, Laura J. Fields

Inquiry: The University of Arkansas Undergraduate Research Journal

It is difficult to underestimate the importance of differential equations in understanding the physical world. These equations, involving not just simple variables like temperature, speed or mass, but also the derivatives, i.e. the rate of change of these variables, are found in nearly every branch of science. Until the mid 20th century, all such equations were thought to be solvable. This was based on the discovery by Leonard Euler that certain differential equations, called ordinary differential equations (ODEs), are indeed always solvable. While ODEs deal with simple conditions, under which some quantity changes with some other quantity and its derivatives, …

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Upper White River Bmp Implementation Project (Nps Final Report), Paul F. Vendrell, K. F. Steele, M. A. Nelson, R. W. Mcnew Dec 2000

Upper White River Bmp Implementation Project (Nps Final Report), Paul F. Vendrell, K. F. Steele, M. A. Nelson, R. W. Mcnew

Technical Reports

The project objective was to monitor agricultural best management practices implemented to minimize sediment, nutrient, and bacterial impact on water quality of the Upper White River watershed. The project targeted the primary agricultural causes of non-point source nutrient and bacterial pollution in three sub-basins of the White River in the Beaver Lake Watershed. Areas with high animal densities targeted high source areas. High source areas were treated with best management practices (BMP) in an effort to reduce the impact to the White River and Beaver Lake. The predominant BMP implemented was waste management, a component of the farm nutrient management …

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Improving Water Quality Through Bmps For Crop Production Systems Whole Farm Soil And Water Management, J. T. Gilmour, L. R. Frye, N. A. Slaton Dec 2000

Improving Water Quality Through Bmps For Crop Production Systems Whole Farm Soil And Water Management, J. T. Gilmour, L. R. Frye, N. A. Slaton

Technical Reports

The major objective of this demonstration project was to assess the usefulness of Global Positioning Systems/Geographic Information Systems (GPS/GIS), water testing, soil testing and yield monitoring in a whole farm water and soil management plan. An important part of this objective was to make recommendations to increase crop productivity and decrease the potential for surface water degradation through erosion and runoff at the farm. The farm was located on 2400 acres in the Bayou de View watershed in Monroe County, Arkansas. The farm lies approximately five miles southwest of the town of Brinkley straddling Highway 17 just south of its …

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