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Articles 2071 - 2100 of 2433

Full-Text Articles in Physical Sciences and Mathematics

Photoacoustic Detection Of Carbonaceous Atmospheric Aerosols, Duane Jackson Jan 1990

Photoacoustic Detection Of Carbonaceous Atmospheric Aerosols, Duane Jackson

Journal of the Arkansas Academy of Science

The role of carbonaceous aerosols in the atmosphere as a risk factor in climatic changes and health effects and state-of-the-art monitoring processes are briefly presented here. In particular, development of a photoacoustic technique for measuring the concentration of carbonaceous particles is discussed. The photoacoustic measurement is based upon detection of pressure waves generated by localized time-dependent heating of air inside the photoacoustic chamber. Heating of air inside the chamber is due to absorption of visible laser radiation by carbon particles present inside the chamber. The laser radiation is chopped, and the resultant pressure signal produced by subsequent heating and cooling …

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Impact Of Microprocessor Protected Mode Programming On Undergraduate Education N Engineering Technology, Robert L. Douglas Jan 1990

Impact Of Microprocessor Protected Mode Programming On Undergraduate Education N Engineering Technology, Robert L. Douglas

Journal of the Arkansas Academy of Science

No abstract provided.

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On-Line Process Fiber Optic Refractometer For Measuring Edible Oil Hydrogenation, Charles F. Cole, Robert A. Sims, Alois (Al) J. Adams Jan 1990

On-Line Process Fiber Optic Refractometer For Measuring Edible Oil Hydrogenation, Charles F. Cole, Robert A. Sims, Alois (Al) J. Adams

Journal of the Arkansas Academy of Science

The process of edible oil partial hydrogenation has improved steadily over the past decades, but few on-line process instruments exist capable of measuring the extent of hydrogenation. This work describes the design of a prototype, on-line fiber optic refractometer for controlling and monitoring of oils. It uses an established correlation between the degree of hydrogenation of an edible oil and its refractive index (Rl). The refractometer cell uses a bare optical fiber in direct contact with processing oil. Equations are given describing the power transmission characteristics of an optical fiber as a function of its cladding Rl. Comparisons between calculated …

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Arkansas Water Resources Research Center Pamphlet, Kenneth F. Steele Jan 1990

Arkansas Water Resources Research Center Pamphlet, Kenneth F. Steele

Technical Reports

Arkansas Water Resources Center (AWRC) works closely with state and federal agencies and academic institutions. Priority research categories are: surface water analysis, ground water pollution, surface and ground water quality/quanity, and water resource management.

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Educational Software Development Using Hypertext And Expert System Software Concepts, Siripong Malasri, Roger R. Easson Jan 1990

Educational Software Development Using Hypertext And Expert System Software Concepts, Siripong Malasri, Roger R. Easson

Journal of the Arkansas Academy of Science

This paper presents two computer software concepts: hypertext and expert systems; which are useful for educational software development. Good educational software enhances the learning process and offers opportunities for faculty to provide additional materials for independent studies, which would otherwise be impossible, due to the limited time and incredible growing rate of technological progress. The hypertext concept offers the students a non-linear learning style, while the expert system concept provides explanation facilities for students to probe the logic of the systems. Both approaches are extremely useful for educational software. With the proper tools, the courseware can be implemented easily and …

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Design Of A Viscometer Using Magnetostriction Of Ferromagnetic Probes, Subhendra Nath Sarkar Jan 1990

Design Of A Viscometer Using Magnetostriction Of Ferromagnetic Probes, Subhendra Nath Sarkar

Journal of the Arkansas Academy of Science

On-line measurement of viscosity of process liquids at process temperature is difficult though industrially very important. A viscometer is designed which can do this up to about 300 °C almost on-line within about 1-8% accuracy except for very viscous liquids like glucose. It uses a ferromagnetic probe designed to mechanically vibrate in the ultrasonic frequency range. An excitation coil sends repeated excitation current pulses to induce mechanical vibration in the probe tip. When placed in a process fluid, the vibration amplitude is damped due to the viscosity of the fluid, and the damped vibration is sensed by Faraday's principle by …

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Characterization Of Radioactivity In Hot Springs National Park, Arkansas, C. E. Epperson, N. R. Rhodes Jan 1990

Characterization Of Radioactivity In Hot Springs National Park, Arkansas, C. E. Epperson, N. R. Rhodes

Journal of the Arkansas Academy of Science

No abstract provided.

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Status Of The Accelerator Project At Uca, Jack Gaiser, Harold L. Pray Jan 1990

Status Of The Accelerator Project At Uca, Jack Gaiser, Harold L. Pray

Journal of the Arkansas Academy of Science

No abstract provided.

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Management Of The Ozark Big-Eared Bat, Plecotus Townsendii Ingens, In Arkansas, Michael J. Harvey, Sam W. Barkley Jan 1990

Management Of The Ozark Big-Eared Bat, Plecotus Townsendii Ingens, In Arkansas, Michael J. Harvey, Sam W. Barkley

Journal of the Arkansas Academy of Science

No abstract provided.

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Analysis, Design And Implementation Of A Pilot Relational Database For Groundwater In The State Of Arkansas, Ray Hashemi-Nassab Jun 1989

Analysis, Design And Implementation Of A Pilot Relational Database For Groundwater In The State Of Arkansas, Ray Hashemi-Nassab

Technical Reports

There are several agencies within the state of Arkansas dealing with underground water. Each agency has its own database that acts as an isolated depository of data. Practically, the communication among these databases is zero, not because there is no need for it, but because the communication is very difficult if not impossible. Data redundancy, inconsistency, and lack of integrity is overwhelming. In this study we have addressed the problem of lack of unity among the databases belonging to different agencies. Also, as an alternative we have developed a relational database. In this database the data was normalized to 4NF. …

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An Expert System For Managing An Activated Sludge Wastewater Treatment Plant, Sandra C. Parker, David G. Parker Jun 1989

An Expert System For Managing An Activated Sludge Wastewater Treatment Plant, Sandra C. Parker, David G. Parker

Technical Reports

A diagnostic expert system for an activated sludge wastewater treatment plant has been designed to link with a relational database management system for obtaining operational parameter values that are used by the program to diagnose operational problems that may occur in the process. The problems that are dealt with by the system are bulking sludge, floating sludge, defloculation, ashing, solids washout, foaming problems, high soluble effluent BOD and problems in the aeration system. The link between the expert system and the database is accomplished via programming that is initiated by the expert system program. The operator of the system is …

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Improving Irrigation Scheduling And Water Use Efficiency In Cotton, Derrick M. Oosterhuis Jun 1989

Improving Irrigation Scheduling And Water Use Efficiency In Cotton, Derrick M. Oosterhuis

Technical Reports

Cotton (Gossypium hirsutum L) is an important crop in the southern United States. The crop is grown in both irrigated and rainfed situations and is seldom free from periods of water shortages at some stage during the season. In recent years the need for consistency in yields and a stable cash flow has resulted in a rapid expansion in the number of irrigated acres of cotton in the Mississippi Delta. Irrigation research has, however, not kept pace with this expansion. This project represents a start at meeting this urgent need. The influence of weather patterns necessitates that these studies be …

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Simulation Of The Fate Of Nitrogen From The Disposal Of Poultry Litter, H. D. Scott Jun 1989

Simulation Of The Fate Of Nitrogen From The Disposal Of Poultry Litter, H. D. Scott

Technical Reports

A PC/AT computer model was developed to simulate the transport of water, nitrate and ammonia in the soil profile after an application of poultry litter to pasture. The model was written using FORTRAN 77 compiler and can be used on any IBM type compatible computer with a math coprocessor. Poultry litter has been shown to be a potential source of plant nutrients, but mismanagement can result in nitrate pollution of the surface and groundwater. The model is composed of a main program, 11 subroutines and three subprograms. An example was shown of the flexibility and dynamic nature of the computer …

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Minimizing The Potential For Groundwater Contamination From Agricultural Point Sources, Joseph H. Massey, Terry L. Lavy, John D. Mattice Jun 1989

Minimizing The Potential For Groundwater Contamination From Agricultural Point Sources, Joseph H. Massey, Terry L. Lavy, John D. Mattice

Technical Reports

An activated charcoal filtration unit was designed to remove pesticides from leftover pesticide solutions and rinsates generated under farm-like conditions. The system, fabricated for less than $1400 using readily available components, effectively removed the pesticides atrazine, benomyl, carbaryl, fluometuron, metolachlor, and trifluralin from wastewater generated on the University of Arkansas Agronomy Farm located in Fayetteville, AR. A total of 2253 L of wastewater were treated using the system. Of these 1768 L were generated from washing out the spray tank (rinsates) while 485 L stemmed from leftover pesticide solutions that were mixed, but not applied. Typical initial pesticide concentrations in …

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Presentation Of Verified Algal Taxa As Reference Sources, Richard L. Meyer Jun 1989

Presentation Of Verified Algal Taxa As Reference Sources, Richard L. Meyer

Technical Reports

A data base of the algae of Arkansas ecoregions has been established to describe the numerous taxa that occur within the aquatic ecosystems included in these regions. The organisms were identified with the aid of diverse literature from throughout the world. These sources are written in multiple languages and the living organisms had to be compared with outline or silhouette drawings. These illustrations may include shading, but none present the true color of the organism but only the characteristics of the descriptive source. Primary characteristics used to identify algae is based upon pigmentation of the plastid and the number and …

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Determining Pesticide And Nitrate Levels In Spring Water In Northwest Arkansas, T. L. Lavy, B. A. Dehart, John D. Mattice Jun 1989

Determining Pesticide And Nitrate Levels In Spring Water In Northwest Arkansas, T. L. Lavy, B. A. Dehart, John D. Mattice

Technical Reports

Occurrences of pesticides in our nations ground water are on the rise. As states become aware of this problem and begin monitoring programs, incidence of contamination will probably increase. Since the problem of pesticides in groundwater is relatively new, little research has centered on the fate of pesticides after they reach the groundwater environment. In Northwest Arkansas efforts to monitor groundwater for pesticides have been small. Twenty-five springs in Northwest Arkansas were sampled in the fall of 1988, and spring of 1989. Analysis for atrazine, alachlor, metolachlor, diuron, and simazine in spring water was preformed using gas liquid chromatography and …

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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.

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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.

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7li Nmr Of Normal Human Erythrocytes, Rao P. Gullapalli, Roger M. Hawk, Richard A. Komoroski Jan 1989

7li Nmr Of Normal Human Erythrocytes, Rao P. Gullapalli, Roger M. Hawk, Richard A. Komoroski

Journal of the Arkansas Academy of Science

Lithium has been known to be an effective medication for people with bipolar disorder. The mechanisms of action of lithium in the brain is not very well understood. NMR spectroscopy and imaging are effective both in determining lithium levels in tissue and brain. We have monitored lithium levels in red blood cells. We have been able to separate intra- and extracellular compartments of lithium using shift reagents, thereby obtaining T^1 's of both the compartments. Lithium uptake as a function of hematocrit was monitored weekly over a 3 week period. The time constant of 50 mM lithium uptake at 25°C …

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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 …

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Determination Of The Suitability Of Arkansas River Water For Municipal, Industrial And Agricultural Use, James W. Moore Jan 1989

Determination Of The Suitability Of Arkansas River Water For Municipal, Industrial And Agricultural Use, James W. Moore

Technical Reports

River water samples from the five sites were collected by the U. S. Geological Survey (USGS) in accordance with their established sampling procedures. Samples for wet chemistry and atomic absorption analyses were delivered to the Bell Engineering Center at the University of Arkansas by USGS personnel. Samples for organics analyses from the Lee Creek, Dardanelle, Little Rock and Pine Bluff sites were delivered by USGS to American Interplex in Little Rock. Samples for organics analyses for the Van Buren site were delivered to the Bell Engineering Center and sent by United Parcel Service (next day air) to Daily Analytical Services …

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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

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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.

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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

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 …

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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

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 …

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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

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 …

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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

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 …

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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

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 …

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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. …

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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 …

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