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 2791 - 2820 of 3135

Full-Text Articles in Physical Sciences and Mathematics

Concept Decomposition, Walter A. Sedelow Jr. Jan 1989

Concept Decomposition, Walter A. Sedelow Jr.

Journal of the Arkansas Academy of Science

Historically, perhaps the most general paradigm for scientists has been decomposition —as with, e.g., 'elements' in chemistry, and the basic structures/processes of theoretical physics. Knowledge representation research is encouraging a somewhat comparable activity in computer science, by way of the study of knowledge representation structures and knowledge representation systems. Symbol sets, rules of usage (including divergent inferencing engines) and conceptual primitives are among the entities involved in this process of decomposition.

Go to article

Preparation Of A Series Of Pyridyl Phenylureas Of Potential Agricultural Interest, Frank L. Setliff, Steve H. Rankin, Mark W. Milstead Jan 1989

Preparation Of A Series Of Pyridyl Phenylureas Of Potential Agricultural Interest, Frank L. Setliff, Steve H. Rankin, Mark W. Milstead

Journal of the Arkansas Academy of Science

Substituted phenylurea derivatives of 3-amino-2-chloro-5-methylpyridine and 5-amino-2-chloro-3- methylpyridine were prepared by treating the amines with appropriately substituted phenyl isocyanates. Structure- confirming spectral data are also presented.

Go to article

Bacterial Quality Of Private Water Wells In Clark County, Arkansas, S. Conine, D. Cox, K. Mitchell, Clark Kuyper, Jimmy D. Bragg Jan 1989

Bacterial Quality Of Private Water Wells In Clark County, Arkansas, S. Conine, D. Cox, K. Mitchell, Clark Kuyper, Jimmy D. Bragg

Journal of the Arkansas Academy of Science

Most private water wells in Clark County appeared to be contaminated by bacteria, apparently entering the wells from surface water seepage. Eighteen to 24% of the wells investigated were positive for fecal contamination. Deeper wells were less often contaminated. More than one-half of the wells sampled exceeded recommended limits of inorganic chemicals for safe potable water. High concentrations of iron and manganese were most common, exceeding recommended limits in more than 40% of the wells

Go to article

Blackland Prairies Of Southwestern Arkansas, Thomas L. Foti Jan 1989

Blackland Prairies Of Southwestern Arkansas, Thomas L. Foti

Journal of the Arkansas Academy of Science

The Blackland Prairie community type has been described in Texas; related communities exist in Alabama and Mississippi. The Arkansas variant of the community has not been described in detail. Since the Arkansas Natural Heritage Commission began a systematic inventory of the community in 1985, more than 36 remnants have been identified that retain substantial natural character. However, all show some degree of disturbance. Based on aerial photo interpretation, aerial inspection, and ground study, an initial description of the community is presented, including original distribution, soil, vegetation and relationship to similar communities of Texas, Mississippi, and Alabama.

Go to article

Soil Micromorphologic Features Of Holocene Surface Weathering And A Possible Late Quaternary Buried Soil, Northwest Arkansas, Diane Phillips, Margaret J. Guccione Jan 1989

Soil Micromorphologic Features Of Holocene Surface Weathering And A Possible Late Quaternary Buried Soil, Northwest Arkansas, Diane Phillips, Margaret J. Guccione

Journal of the Arkansas Academy of Science

Micromorphologic features of an alfisol developed in White River alluvium near Fayetteville, Arkansas are typical for this soil order. The A horizon has a relatively high organic matter content and an abundance of quartz sand grains with a silt and clay matrix. Voids are relatively common and some have been partly infilled. In contrast to the A horizon, the E horizon has less organic matter, larger voids, and some weak orientation of the clay matrix. The parent material for these horizons was deposited in the past 4,700 years and these pedologic horizons have formed since that time. In the underlying …

Go to article

Virtually Interactive Large-Scale Model For Arkansas: User's Guide (Vilma), Rosalinda R. A. Cantiller, Richard C. Peralta Aug 1988

Virtually Interactive Large-Scale Model For Arkansas: User's Guide (Vilma), Rosalinda R. A. Cantiller, Richard C. Peralta

Arkansas Water Resources Center Technical Reports

This user’s guide supports the use of VILMA (Virtually Interactive Large-scale Model for Arkansas). This document presents the basic concepts in Chapter I. Chapter II discusses the execution steps that the user follows during a VILMA session. Chapter III provides a detailed illustration of example data files. Chapter IV presents two example VILMA sessions. Finally, Chapter V elaborates on additional concepts. The Appendices consist of relevant program listings, instructions, and example files. In this user’s guide, the word "interactive" means the user enters his responses to the prompts that appear on a computer terminal while he is logged on to …

Go to article

Estimating Potential Ground And Surface Water Pollution From Land Application Of Poultry Litter - Ii, D. C. Wolf, J. T. Gilmour, P. M. Gale Jun 1988

Estimating Potential Ground And Surface Water Pollution From Land Application Of Poultry Litter - Ii, D. C. Wolf, J. T. Gilmour, P. M. Gale

Arkansas Water Resources Center Technical Reports

In Arkansas, approximately 1 Tg of poultry (Gallus gallus domesticus) manure and litter is produced annually. These waste products are commonly applied to pastures as a soil amendment or fertilizer, but excessive application rates and poor management practices could result in nutrient contamination of ground and surface water. The purpose of this study was to: (1) assess the nutrient concentrations in poultry manure and (2) evaluate the nitrogen loss from land-applied poultry litter and manure due to ammonia volatilization and denitrification. Analyses for total Kjeldahl nitrogen (TKN), inorganic nitrogen (Ni), phosphorus (P), and potassium (K) were compared in 12 wet …

Go to article

Development Of A Combined Quantity And Quality Model For Optimal Management Of Unsteady Groundwater Flow Fields, R. C. Peralta, J. Solaimanian, C. L. Griffis Jun 1988

Development Of A Combined Quantity And Quality Model For Optimal Management Of Unsteady Groundwater Flow Fields, R. C. Peralta, J. Solaimanian, C. L. Griffis

Arkansas Water Resources Center Technical Reports

Presented are alternative techniques for including conservative solute transport within computer models for optimizing groundwater extraction rates. Unsteady two-dimensional flow and dispersed conservative solute transport are assumed. Comparisons are made of the practicality of including modified forms of implicit and explicit finite difference solute transport equations within optimization models. These equations can be calibrated and subsequently used within a MODCON procedure. The MODCON modelling procedure consists of an integrated series of five optimization or simulation modules. The procedure is applicable for either an entire aquifer system or for a subsystem of a larger system. The first module, A, computes physically …

Go to article

Qualitative And Quantitative Aquatic Algal Data Compilation To Determine Macrotrends - Iv, Richard L. Meyer Jun 1988

Qualitative And Quantitative Aquatic Algal Data Compilation To Determine Macrotrends - Iv, Richard L. Meyer

Arkansas Water Resources Center Technical Reports

A data base of the algae of Arkansas ecoregions has been estabblished by the use of a relational data base management system (dBase III plus). The system was chosen to be readily available for a variety of microcomputers using MS- and PC-DOS. The data base contains taxonomic fields from division through variety, synonymy, authors, initial description, date, and definitive descriptive source. The data are cross-referenced by ecoregion, Round's community and subcommunity designations. The data base contains greater than 1,500 taxonomic records in all divisions and classes of freshwater algae. The data are sortable by any of the included parameters. The …

Go to article

Long-Term Reconstruction And Analysis Of White River Streamflow, M. K. Cleaveland, D. W. Stahle, J. G. Hehr Jun 1988

Long-Term Reconstruction And Analysis Of White River Streamflow, M. K. Cleaveland, D. W. Stahle, J. G. Hehr

Arkansas Water Resources Center Technical Reports

A 281-year reconstruction of White River annual runoff at Clarendon, Arkansas, was developed from a regional average of nine Oklahoma, Missouri, and Arkansas tree-ring chronologies (six post oak, Quercus stellata, and three baldcypress, Taxodium distichum). Inhomogeneity of the gaged series was detected with both double mass analysis (using state average total annual Arkansas precipitation) and regression (using the regional tree-ring average). Simple regression calibrated the homogeneous runoff data with the average ring width data from 1930 to 1980. Comparing the reconstruction with independent data verified the regression model. Variance of the reconstruction increases significantly during the 20th century, a change …

Go to article

Response Of Fish Communities To Habitat Alteration In A Small Ozark Stream, Danny J. Ebert, Stephen P. Filipek Jan 1988

Response Of Fish Communities To Habitat Alteration In A Small Ozark Stream, Danny J. Ebert, Stephen P. Filipek

Journal of the Arkansas Academy of Science

From 1984 to 1986, the Arkansas Highway and Transportation Department reconstructed and upgraded a portion of St. Hwy. 123 west of St. Hwy.7 at Pelsor, Arkansas. As a result of the construction, portions of Haw Creek, Johnson County, Arkansas, a third order stream in the Boston Mountains Ecoregion, were straightened and channelized. In reconstructing specific stream reaches, stream banks were riprapped and vegetated, gabions constructed and positioned, stream substrates and pool-riffle ratios altered. Instream and riparian habitat and fish biomass and diversity in altered reaches were radically altered. Channelized reaches became wide and shallow, lacking overstory cover and pools. Substrate …

Go to article

Arkansas' Timber Resource: Yesterday, Today, And Tomorrow, Richard A. Kluender, R. L. Willett Jan 1988

Arkansas' Timber Resource: Yesterday, Today, And Tomorrow, Richard A. Kluender, R. L. Willett

Journal of the Arkansas Academy of Science

Demand for forest products continues to rise. Arkansas provides about 4% of the U.S. total forest production and about 12% of the south central region production. Questions exist about the ability of current forest resources to completely meet anticipated future demand. In 1985, the U.S. Forest Service and the Arkansas Timber Study Committee began to analyze the existing forest base to determine whether future demand could be met from the current forest, or if not, what management changes were needed to help meet future demand. In 1985, Arkansas forests covered approximately 48% of the total land area of the state. …

Go to article

Equations Of Variation For Ordinary Differential Equations On Manifolds, J. B. Bennett Jan 1988

Equations Of Variation For Ordinary Differential Equations On Manifolds, J. B. Bennett

Journal of the Arkansas Academy of Science

No abstract provided.

Go to article

Measurements Of The Drag On Spheres Falling Through The Air, J. G. Ross, Stephen R. Addison, N.O (Jack) Gaiser Jan 1988

Measurements Of The Drag On Spheres Falling Through The Air, J. G. Ross, Stephen R. Addison, N.O (Jack) Gaiser

Journal of the Arkansas Academy of Science

No abstract provided.

Go to article

Movement And Transformation Of Selected Organic Pollutants In Subsurface Environmet In Arkansas, Ali U. Shaikh Jun 1987

Movement And Transformation Of Selected Organic Pollutants In Subsurface Environmet In Arkansas, Ali U. Shaikh

Arkansas Water Resources Center Technical Reports

Several subsurface soil and groundwater samples from eastern, southern and central Arkansas were analyzed for chlorinated organic compounds commonly used as pesticides and industrial chemicals. No significant amount of these compounds were found in these samples. The adsorption/partition characteristics of some of these compounds, such as dichlorophenols, aldrin and endrin, were determined in siltloam, sandyloam and clay soils collected from the above geographical locations. Results indicate that there is considerable difference in retention capability of different types of soils with respect to different pollutants. The partition coefficient of a particular compound in a certain type of soil can be related …

Go to article

Assessment Of The Effects Of Household Chemicals Upon Individual Septic Tank Performances, Mark A. Gross Jun 1987

Assessment Of The Effects Of Household Chemicals Upon Individual Septic Tank Performances, Mark A. Gross

Arkansas Water Resources Center Technical Reports

A laboratory study and a field study were performed to determine the amounts of specific household chemicals required to destroy bacteria populations in individual domestic septic tanks. The particular chemicals evaluated include liquid chlorine bleach, High Test Hypochlorite (HTH), Lysol disinfectant and Drano crystal. The laboratory study was performed to determine the approximate chemical concentrations to destroy the bacteria in the septic tank, and the field study showed the actual effect of the chemicals upon the bacteria in terms of reduction of the number of bacteria in the septic tank as well as the time required for the bacterial population …

Go to article

Estimating Potential Ground And Surface Water Pollution From Land Application Of Poultry Litter, J. T. Gilmour, D. C. Wolf, P. M. Gale Jun 1987

Estimating Potential Ground And Surface Water Pollution From Land Application Of Poultry Litter, J. T. Gilmour, D. C. Wolf, P. M. Gale

Arkansas Water Resources Center Technical Reports

In 1985, more than 750 million broiler chickens were produced in Arkansas. During the same year over 15 million laying chickens produced 3.6 million eggs. The waste products of these agricultural production systems, poultry litter and manure, were about 1 million metric tons. As a result of land application of these wastes, about 5,000 metric tons of annnonium N and 12,000 metric tons of mineralized nitrogen were applied to Arkansas pastures in 1985. Manures contributed about 2-3 percent of the total. The objective of this research was to quantify major components of the nitrogen cycle which influence the ground and …

Go to article

Qualitative And Quantitative Aquatic Algal Data Compilation To Determine Macrotrends- Iii, Richard L. Meyer Jun 1987

Qualitative And Quantitative Aquatic Algal Data Compilation To Determine Macrotrends- Iii, Richard L. Meyer

Arkansas Water Resources Center Technical Reports

A data base of the algae of Arkansas ecoregions has been established by the use of a relational data base management system (dBase III plus). The system was chosen to be readily available for a variety of microcomputers using MS- and PC-DOS. The data base contains taxonomic fields from division through variety, synonymy, authors, initial description, date and definitive descriptive source. The data are cross-referenced by ecoregion, Round's community and subcommunity designations. The data base contains approximately 1,500 taxonomic records in all divisions and classes of freshwater algae. The data are sortable by any of the included parameters. The data …

Go to article

Chemical Properties Of Soils And Streams In Natural And Disturbed Forest Ecosystems In The Ouachita Mountains, R. S. Beasley, E. L. Miller, E. R. Lawson Jun 1987

Chemical Properties Of Soils And Streams In Natural And Disturbed Forest Ecosystems In The Ouachita Mountains, R. S. Beasley, E. L. Miller, E. R. Lawson

Arkansas Water Resources Center Technical Reports

One year of pre-harvest and five years of post-harvest water chemistry data were collected and analyzed for N03-N, TKN, TP, OP, K and Ca on nine small watersheds in the Ouachita Mountains of central Arkansas. Gross exports of all nutrients except TKN were significantly increased by cl earcutting followed by mechanical site preparation and broadcast burning of slash. Discharge-weighted nutrient concentrations were increased only for OP, K and Ca. The treatment effect was brief, lasting only one year. The first harvest of a selection system regime had no measurable effect on gross losses or concentrations of nutrients. Precipitation chemistry measurements …

Go to article

Development Of A Combined Quanity And Quality Model For Optimal Groundwater Management, R. C. Peralta, J. Solaimanian, S. A. Prathapar, C. L. Griffis Jun 1987

Development Of A Combined Quanity And Quality Model For Optimal Groundwater Management, R. C. Peralta, J. Solaimanian, S. A. Prathapar, C. L. Griffis

Arkansas Water Resources Center Technical Reports

Presented is a procedure for incorporating solute transport as linear constraints within computer models for optimizing regional groundwater extraction strategies. The MODCON modelling procedure uses linear goal programming, embedded linearized equations for flow and solute transport and a MOC simulation model. Assumed is 2D flow and solute transport and a dispersed conservative contaminant. The MODCON procedure develops steady groundwater extraction strategies that will satisfy future groundwater quality constraints while simultaneously causing future piezometric heads to be as close to current heads as possible. The procedure is applied to a 160 square mile area in southeastern Arkansas.

Go to article

Land Use Effects On Ground Water Quality In Carbonate Rock Terrain, Kenneth F. Steele, James C. Adamski Jun 1987

Land Use Effects On Ground Water Quality In Carbonate Rock Terrain, Kenneth F. Steele, James C. Adamski

Arkansas Water Resources Center Technical Reports

A control site with a natural setting and an experimental site with significant agriculture land use were studied in the Ozark Region of Arkansas in order to determine the effect of land use on water quality in a carbonate rock terrain. The vast majority of the two sites have the Boone Limestone exposed which combined with the underlying St. Joe is the major aquifer for drinking water in the area. The sites also are similar in terms of lineament patterns (number, length and orientation), soil, slope and vegetation. Ground water samples were collected primarily from springs during three seasons (late …

Go to article

Improved Synthesis Of 5-Methylbenz(A)Anthracene, Jia Che, Dominic T.C. Yang Jan 1987

Improved Synthesis Of 5-Methylbenz(A)Anthracene, Jia Che, Dominic T.C. Yang

Journal of the Arkansas Academy of Science

A revised synthesis of 5-methylbenz(a)anthracene is reported. It involves only three simple and convenient steps starting from a commercially available compound, and gives a 82% overall yield. Bromination of 5-methylbenz(a)anthracene with N-bromosuccinimide (NBS) in carbon tetrachloride furnishes 5-bromomethylbenz(a)anthracene in a 92% yield. When bromination is carried out using dimethylformamide as the solvent, 7-bromo-5-methylbenz(a)anthracene is formed as the exclusive product.

Go to article

Botanical Evidence For Holocene Movement Of Rock Streams In Arkansas, S. Marie Lookingbill, Malcolm K. Cleaveland, Margaret J. Guccione Jan 1987

Botanical Evidence For Holocene Movement Of Rock Streams In Arkansas, S. Marie Lookingbill, Malcolm K. Cleaveland, Margaret J. Guccione

Journal of the Arkansas Academy of Science

Botanical studies of rock streams on the western half of Rich Mountain and on the north slope of Mt. Magazine in Arkansas question the common presumption that such streams require periglacial conditions to form, and are now inactive relict features in this area. Trees along the margins of the streams examined show abundant evidence of trauma resulting from Late Holocene movement, in the form of bent and tilted stems. Cross sections of trees demonstrate marked eccentric growth associated with tilting and cambial trauma associated with corrasion by rocks. That this damage is not the result of excessive snow loading is …

Go to article

Physiography And Hydrology Of The Upper Saline River, Saline And Garland Counties, Arkansas, John D. Rickett Jan 1987

Physiography And Hydrology Of The Upper Saline River, Saline And Garland Counties, Arkansas, John D. Rickett

Journal of the Arkansas Academy of Science

The Saline River is one of two significant river systems in Arkansas that does not have a major impoundment. In the interest of continuing this status, this project was conducted. Thirty-five sites on the four major and six minor tributaries of the upper saline River, Saline and Garland Counties, Arkansas, were visited a total of 58 times between 24 January 1985 and 21 November 1986. Habitat quality was assessed by measuring twelve physicochemical features and flow parameters, analyzing substrate composition and describing stream morphometry. Physicochemical measurements were within the limits of good quality habitat, and most of the readings were …

Go to article

Textural And Lithologic Differences Of Cretaceous, Tertiary, And Quaternary Gravels Of South Arkansas, Lesli Wood Jan 1987

Textural And Lithologic Differences Of Cretaceous, Tertiary, And Quaternary Gravels Of South Arkansas, Lesli Wood

Journal of the Arkansas Academy of Science

Stream gravels have been derived from the Ouachita Mountains since at least Cretaceous times. Past studies have assigned ages to gravel deposits in the basins of the Saline and Little Missouri Rivers on the basis of altitude above local floodplains. This study examines the lithologies and textures of seven gravel outcrops ranging in age from Cretaceous to Quaternary to determine whether any patterns of variation based on assigned ages, variable sources, or precise depositional setting can be discerned. No variation patterns could be found for size distributions of sand-sized and larger fractions. However, the amount of silt-clay matrix decreases through …

Go to article

Optimal Groundwater Mining Methods, Richard C. Peralta, Krzysztof G. Kowalski Dec 1986

Optimal Groundwater Mining Methods, Richard C. Peralta, Krzysztof G. Kowalski

Arkansas Water Resources Center Technical Reports

No abstract provided.

Go to article

Long-Term Effects Of Tillage On The Retention And Transport Of Soil Water, H. D. Scott, L. S. Wood, W. M. Miley Jun 1986

Long-Term Effects Of Tillage On The Retention And Transport Of Soil Water, H. D. Scott, L. S. Wood, W. M. Miley

Arkansas Water Resources Center Technical Reports

Quantitative measurements were made of the physical and chemical properties of two virgin prairie soils, Crowley and Jay, that remain in their native Arkansas environments and of similar soils that had been tilled extensively. Comparisons were made of soil properties at several depths. When compared with the tilled soils the virgin soils had higher organic matter contents, saturated hydraulic conductivities and water retained at several applied pressures. Bulk densities and hydraulic resistances were lower in the virgin soils. For the Crowley silt loam, values of pH and elemental contents of the virgin soil were higher than those of the tilled …

Go to article

Algal Growth Potentials And Heavy Metal Concentrations Of The Primary Streams To Upper Beaver Lake, Richard L. Meyer, W. Reed Green, Kenneth F. Steele, Diana Wickliff Jun 1986

Algal Growth Potentials And Heavy Metal Concentrations Of The Primary Streams To Upper Beaver Lake, Richard L. Meyer, W. Reed Green, Kenneth F. Steele, Diana Wickliff

Arkansas Water Resources Center Technical Reports

Meyer and Green (1984) demonstrated the probable inhibition of algal growth potential by heavy metals in upper Beaver Lake. Upper Beaver Lake receives water from three tributaries. One contains a small reservoir and the combined streams receive sewage input. Collections were made approximately monthly at eight sites for the Algal Assay Bottle Test (AABT) and heavy metal analysis. In general, AABT results indicated that the collections above the sewage lnput were phosphorus limited while those below were nitrogen or combined nitrogen and phosphorus limited. Growth inhibition occurred during summer and early fall at various sites with greater inhibition at the …

Go to article

Local Water Resource Information Management System, David G. Parker, Sandra C. Parker Jun 1986

Local Water Resource Information Management System, David G. Parker, Sandra C. Parker

Arkansas Water Resources Center Technical Reports

A Beaver Lake water quality database has been designed as a relational database. It has been implemented using software called R:base 5000, a system available for microcomputers using MS- or PC- DOS operating systems. The data in the database include that concerned with the author(s), title, date of publication, agency doing the study, agency funding the study and complete reference for the document. Other aspects of the database are designed to allow retrievals based on any author, study dates, parameters measured and keywords.

Go to article

The Behavior Of Soluble Salt In Sharkey Clay- Ii, J. T. Gilmour, R. E. Baser, H. D. Scott, J. A. Ferguson Jun 1986

The Behavior Of Soluble Salt In Sharkey Clay- Ii, J. T. Gilmour, R. E. Baser, H. D. Scott, J. A. Ferguson

Arkansas Water Resources Center Technical Reports

Soluble salts have been shown to accumulate in Arkansas soils in sufficient quantities to impair crop plant growth. The major objective of this study was to describe the behavior of soluble chloride salt over long time periods in Sharkey clay - a major Mississippi Delta soil. Prior to flooding rice, leaching of chloride in response to rainfall was observed. The inclusion of a sandy subsoil layer reduced this effect presumably by limiting downward movement of water under unsaturated conditions. No lateral movement of the chloride salt was found during the period prior to flooding. Removal of soluble chloride salts from …

Go to article

First Prev Next Last