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Articles 2011 - 2040 of 2433
Full-Text Articles in Physical Sciences and Mathematics
Reconnaissance Survey Of Nitrate Concentrations In Ground Water In Howard And Pike Counties, Arkansas, Travis Thornton, Kenneth F. Steele
Reconnaissance Survey Of Nitrate Concentrations In Ground Water In Howard And Pike Counties, Arkansas, Travis Thornton, Kenneth F. Steele
Technical Reports
In recent years, the rapid growth of poultry and hog production in Arkansas has caused concern regarding nitrate contamination of the ground water. In the study area of Pike and Howard Counties, the number of hogs has increased from 3,300 hogs in 1970 to 75,000 hogs in 1990. Poultr¥ production for the area has increased from 38,933,000 per year 1n 1970 to 62,774,000 per year in 1990. As animal production increases, so does the amount of animal waste that must be disposed. Hog production is of particular concern. Typical hog operations store concentrated animal waste in lagoons prior to land …
Fact Sheet No.1: Nonpoint Source Pollution And Water Quality Of Northwest Arkansas, T. C. Daniel, D. R. Edwards, D. C. Wolf, K. F. Steele, M. J. Cochran
Fact Sheet No.1: Nonpoint Source Pollution And Water Quality Of Northwest Arkansas, T. C. Daniel, D. R. Edwards, D. C. Wolf, K. F. Steele, M. J. Cochran
Technical Reports
Preservation of a clean, safe, and biologically diverse environment can capture public attention as few other issues can. Indeed, recent international cooperative efforts indicate that there is an increasing global desire to pass on to future generations an environment at least equal in quality to the one we inherited.
Model For The Co Poisoning Of Hydrodesulfurization Catalysts. Synthesis And Structure Of {Ru(Co)[Pph2sc12h7)]2cl2}.2ch2br2, Mark Draganjac, Thomas B. Rauchfuss, Arnold L. Rheingold
Model For The Co Poisoning Of Hydrodesulfurization Catalysts. Synthesis And Structure Of {Ru(Co)[Pph2sc12h7)]2cl2}.2ch2br2, Mark Draganjac, Thomas B. Rauchfuss, Arnold L. Rheingold
Journal of the Arkansas Academy of Science
The treatment of {Ru[(PPh2SC12H7)]2Cl2} with CO at ambient conditions results, after work up, in the isolation of the monocarbonylated species {Ru(CO)[(PPh2SC12H7)]2Cl2}, I. Crystals of I(C51H38Br4Cl20P2RuS2; F.W. = 1284.6) are triclinic; Ppa= 11.587(3), b = 13.010(4), c = 17.309(4) A, a = 93.32(2)°, p = 106.51(2)°, y = 91.29(2)°; Z= 2; V=2495(1) A';d^,. = 1.709 gem 1 X(MoKa) = 0.71073 A, = 37.7 cm 1 ;R =0.0748; Rw = 0.0714 for 4141 unique reflections. The geometry about the Ru(II) center is pseudooctahedral, with the phosphine ligands in the trans configuration. The Ru-S bond distance is 2.425(3) A.
Bacteriological Water Quality Of Beaver Reservoir, Arkansas, Jimmy D. Bragg, Mark E. Clark
Bacteriological Water Quality Of Beaver Reservoir, Arkansas, Jimmy D. Bragg, Mark E. Clark
Journal of the Arkansas Academy of Science
Beaver Reservoir water quality was determined through enumeration of Total coliforms and Fecal coliforms bacterial parameters at selected locations during 1991. Several areas of the reservoir contained high numbers of indicator bacteria, suggesting excessive fecal contamination. Significant numbers of salmonella-like bacteria were also cultured on SS agar, and several strains were serotyped positive for Salmonella antigens.
Schroedinger Equation With Spherically Averaged Potentials, C. A. Hughes
Schroedinger Equation With Spherically Averaged Potentials, C. A. Hughes
Journal of the Arkansas Academy of Science
Using a method adapted from few—body hyperspherical techniques, an approach to the solution of the Schroedinger equation with nonspherical potentials is discussed. The method is to spherically average the potential over spherical angles and then solve the resulting set of coupled differential equations. A discussion of how this method is applied to the Stark effect is presented.
Development Of A Variable Wavelength Flame Infrared Emission Gas Chromatography Detector, Weiqun Zhang, M. Keith Hudson, Mokhtar Mofidi
Development Of A Variable Wavelength Flame Infrared Emission Gas Chromatography Detector, Weiqun Zhang, M. Keith Hudson, Mokhtar Mofidi
Journal of the Arkansas Academy of Science
No abstract provided.
Scf-Mo And Monte Carlo Calculations Of Poly (Dimethylsiloxane), Shannon H. Brownfield, Jerry A. Darsey
Scf-Mo And Monte Carlo Calculations Of Poly (Dimethylsiloxane), Shannon H. Brownfield, Jerry A. Darsey
Journal of the Arkansas Academy of Science
Self-consistent-field molecular orbital calculations are being used more and more extensively in determining the energies and properties of various confirmations of polymers. We are using the semi-quantum mechanical procedure MNDO (moderate neglect of differential overlap) to obtain various rotational conformations states of poly(dimethylsiloxane) (PDMS). Before calculation of these states, the molecule is geometrically optimized by using the ab initio procedure Guassian 86 at the 3-21G basis set level. Generations of 144 rotational states by rotating about two bonds simultaneously in increments of 30° were created. A potential energy surface was created from which Monte Carlo generated several polymer characteristics including …
4-Substituted Anilides Of 2,6- And 5,6- Dichlorolicotinic Acid. Potential Agricultural Agents, Frank L. Setliff, Nikhil G. Soman
4-Substituted Anilides Of 2,6- And 5,6- Dichlorolicotinic Acid. Potential Agricultural Agents, Frank L. Setliff, Nikhil G. Soman
Journal of the Arkansas Academy of Science
A series of 4-substituted anilides of 2,6- and 5,6 dichloronicotinic acid were prepared. The acids were first converted to their acid chlorides, which were in turn treated with the appropriate 4-substituted aniline in chloroform. A total of 16 anilides was thus prepared, and their structures confirmed. These compounds were prepared for testing as possible herbicidal, pesticidal or fungicidal agents
Development Of Organic Mud Mounds In A Mixed Carbonate-Siliciclastic Depositional Environment, John M. Ryan, Doy L. Zachry
Development Of Organic Mud Mounds In A Mixed Carbonate-Siliciclastic Depositional Environment, John M. Ryan, Doy L. Zachry
Journal of the Arkansas Academy of Science
Organic carbonate mud mounds in the Prairie Grove Member of the Hale Formation developed on a shallow shelf swept by competent tidal currents. The mounds were stabilized by crustose red algae and fostered a sheltered setting where phylloid algae and marine invertebrates could thrive. The mounds supplied skeletal sediment locally to the intermound areas as well as regionally along the stable platform. This sediment mixed with quartz sand to form a major mixed carbonate-siliciclastic system in northwestern Arkansas.
Comparison Of Two Models For Breakdown Waves, Debra Burris, Mostafa Hemmati
Comparison Of Two Models For Breakdown Waves, Debra Burris, Mostafa Hemmati
Journal of the Arkansas Academy of Science
In this paper, the two theories concerning the propagation of breakdown waves are compared. The two theories are as follows: 1. The photoionization theory, in which the driving force of the propagation is the electromagnetic radiation from the hot gas generated at the electrode with the greatest potential gradient. 2. The electron fluid dynamical theory, in which the driving force of the propagation is the partial pressure of the high temperature electron gas generated in the neighborhood of the pulsed electrode. Successes in explaining the experimental data will be compared.
Hammett Correlations In The 1H Nmr Spectra Of Some N-Arlydihalonicotinamides, Frank L. Setliff, Nikhil G. Soman, Jody Z. Caldwell, Debra L. Rogers
Hammett Correlations In The 1H Nmr Spectra Of Some N-Arlydihalonicotinamides, Frank L. Setliff, Nikhil G. Soman, Jody Z. Caldwell, Debra L. Rogers
Journal of the Arkansas Academy of Science
Excellent linear correlations of amide proton chemical shifts (Snh) (in DMSO-d6 ) with Hammett substituent constants (5) for a series of 4-substituted anilides of four dihalonicotinic acid systems were observed. Dihalonicotinanilides with chlorine in the pyridine 2 - position exhibited a more positive slope in a Hammett plot of S^H vs - aR- where R is the substituent in the 4 position of the benzene ring. This observation is explained in terms of the inductive effect of chlorine which results in a slightly more acidic amide proton, which in turn causes an enhanced hydrogen bonding tendency to solvent. Four disubstituted …
Effect Of Aerosols On Climate Change, Haiyin Sun, Malay K. Mazumder
Effect Of Aerosols On Climate Change, Haiyin Sun, Malay K. Mazumder
Journal of the Arkansas Academy of Science
A modified two-stream approximation is presented, which includes the effect of solar zenith angle and is applicable to study the effect of aerosols on both regional and global climate changes. More realistic results are derived. A reasonable critical value of 0.8 for aerosol single scattering albedo to determine whether the aerosols will heat or cool the climate is derived
Zooplankton Community Abundance And Diversity In Dardanelle Reservoir, Arkansas, 1981-1990, John D. Rickett, Robert L. Watson
Zooplankton Community Abundance And Diversity In Dardanelle Reservoir, Arkansas, 1981-1990, John D. Rickett, Robert L. Watson
Journal of the Arkansas Academy of Science
Zooplankton samples were collected quarterly from five stations representing the discharge bay and four "control" or "dispersing impact" stations. Rotifers dominated all samples numerically and by the number of taxa. All major groups (Rotifera, Cladocera, Copepoda, and Protozoa) exhibited greatest abundances during the summer. Quarterly variations in abundance and number of taxa were documented. Except for an increase in taxonomic analysis detail between 1981 and 1984 resulting in several more taxa added to the list, no long-term increases, declines or repeating cycles were apparent. Margalef's Richness Index reflected this change and showed a long-term increase with evidence of a 5- …
Phytoplankton Community Abundance And Diversity In Dardanelle Reservoir, Arkansas, 1981-1990, John D. Rickett, Robert L. Watson
Phytoplankton Community Abundance And Diversity In Dardanelle Reservoir, Arkansas, 1981-1990, John D. Rickett, Robert L. Watson
Journal of the Arkansas Academy of Science
Phytoplankton samples were collected quarterly from 1981-1990 at five stations representing discharge water from Arkansas Nuclear One, a nuclear generating station, and four "control" or "dispersal evaluation" stations. Seventy-five taxa representing five divisions were identified and enumerated. Community structure was evaluated using abundances, number of taxa, and Margalef's Richness, Shannon's Heterogeneity and Pielou's Evenness indices. No long-term trends were identified, but the beginning of cyclic variations, with a 7-year periodicity, in abundance, number of taxa, and Shannon's and Pielou's indices were apparent. Margalef's index values were constant during most of the study period. For all samples, t-tests and Mann-Whitney U …
Using Physical, Chemical And Biological Indicators To Assess Water Quality On The Ouachita National Forest Utilizing Basin Area Stream Survey Methods, J. Alan Clingenpeel, Betty G. Cochran
Using Physical, Chemical And Biological Indicators To Assess Water Quality On The Ouachita National Forest Utilizing Basin Area Stream Survey Methods, J. Alan Clingenpeel, Betty G. Cochran
Journal of the Arkansas Academy of Science
The Ouachita National Forest (ONF) has developed a series of Best Management Practices (BMP's) designed to protect water quality and associated beneficial uses (fisheries, municipal water supplies, etc.). A monitoring program is necessary to document the effectiveness of that protection. The Basin Area Stream Survey (BASS) methodology provides a monitoring link from BMP's to the aquatic ecosystems. The goal of BASS is to identify the physical, chemical and biological characteristics of a stream in a format that will allow comparisons with other streams, and indicate when a stream is being impacted. Six index streams within two ecoregions were selected and …
Evaluation Of Water Quality Data - Beaver Lake - Table Of Contents Through Section Iii, (Part I), James W. Moore
Evaluation Of Water Quality Data - Beaver Lake - Table Of Contents Through Section Iii, (Part I), James W. Moore
Technical Reports
No abstract provided.
Evaluation Of Water Quality Data - Blue Mountain Lake, James W. Moore
Evaluation Of Water Quality Data - Blue Mountain Lake, James W. Moore
Technical Reports
No abstract provided.
Evaluation Of Water Quality Data - Beaver Lake - Appendices A - Bt, (Part Iii), James W. Moore
Evaluation Of Water Quality Data - Beaver Lake - Appendices A - Bt, (Part Iii), James W. Moore
Technical Reports
No abstract provided.
Evaluation Of Water Quality Data - Beaver Lake - Appendices C - K, (Part Iv), James W. Moore
Evaluation Of Water Quality Data - Beaver Lake - Appendices C - K, (Part Iv), James W. Moore
Technical Reports
No abstract provided.
Evaluation Of Water Quality Data - Beaver Lake - Section Iv Through Table Xli, (Part Ii), James W. Moore
Evaluation Of Water Quality Data - Beaver Lake - Section Iv Through Table Xli, (Part Ii), James W. Moore
Technical Reports
No abstract provided.
Oklahoma State University And University Of Arkansas, Fayetteville Cooperative Report On Evaluation And Assessment Factors Affecting Water Quality Of The Illinois River In Arkansas, Richard L. Meyer, Art V. Brown, David G. Parker
Oklahoma State University And University Of Arkansas, Fayetteville Cooperative Report On Evaluation And Assessment Factors Affecting Water Quality Of The Illinois River In Arkansas, Richard L. Meyer, Art V. Brown, David G. Parker
Technical Reports
No abstract provided.
Determination Of Optimal Timing Of Poultry Waste Disposal By Meteorological, Hydrological, And Water Quality Modeling Techniques, D. R. Edwards, T. C. Daniel
Determination Of Optimal Timing Of Poultry Waste Disposal By Meteorological, Hydrological, And Water Quality Modeling Techniques, D. R. Edwards, T. C. Daniel
Technical Reports
Approximately one million Mg of broiler litter were generated in conjunction with Arkansas' 1989 broiler production. Common practices for disposal of the waste have the potential to damage the quality of downstream rivers and lakes. This possibility is enhanced due to the concentration of broiler production in areas of the state with shallow soils, steep slopes, and limited suitable disposal area. Since the risk of pollution is greatest immediately following disposal and increases with rainfall depth and intensity, adverse water quality impacts may be mitigated by timing the application to coincide with low probability of surface losses of the nutrients …
The Aquatic Macroinvertebrates Of The White River National Wildlife Refuge, Steve W. Chordas Iii, George L. Harp
The Aquatic Macroinvertebrates Of The White River National Wildlife Refuge, Steve W. Chordas Iii, George L. Harp
Technical Reports
The primary purpose of this study was to survey the diversity of the aquatic macroinvertebrates of the White River National Wildlife Refuge (WRNWR). Determining relative abundance and distributional and seasonal patterns were secondary objectives. No comprehensive investigations of the WRNWR aquatic macroinvertebrates had been conducted previously, and it was hypothesized that this relatively undisturbed area may serve as a refugium. Further, this study provides base line data by which management programs can be composed. Thirty sampling stations were established within the WRNWR. Samples were collected from north to south at a basic rate of five stations per month. Revisit collections …
Water Quality As Affected By Pesticides In Rice Production, W. G. Johnson, T. L. Lavy, J. D. Mattice, B. W. Skulman, R. E. Talbert, R. J. Smith
Water Quality As Affected By Pesticides In Rice Production, W. G. Johnson, T. L. Lavy, J. D. Mattice, B. W. Skulman, R. E. Talbert, R. J. Smith
Technical Reports
Studies were conducted to determine the environmental persistence of the rice pesticides triclopyr, 2,4-D, benomyl and quinclorac. Triclopyr half-lives ranged from <7 d to >100 d depending on depth within the soil profile and clay content. Triclopyr persistence increased as depth within the profile increased and clay content increased. The benomyl metabolite MBC was present at greater than 50% of the initial amount after 9 months in the field. In simulated carryover field studies quinclorac exhibited the greatest potential for injury to subsequent rotational crops. Cotton and soybean growth was reduced when planted at four weeks after quinclorac application. The adsorption of triclopyr …7>
Determination Of The Abient Toxicity Of The Tailwater Of Nimrod Lake, John T. Knight
Determination Of The Abient Toxicity Of The Tailwater Of Nimrod Lake, John T. Knight
Technical Reports
The objective of this research was to determine if ambient toxicity exists in the receiving stream below a reservoir in which water from the hypolimnion is released. The Ceriodaphnia 7-day test was utilized to determine if toxicity existed. This test is routinely used in the monitoring of municipal and industrial effluent. It has also been utilized in determining if ambient toxicity exists within receiving streams. Nimrod Lake is a flood control impoundment on the Fourche LaFave River in west central Arkansas. The literature suggest that during stratification the hypolimnetic release contains high levels of iron, manganese, ammonia and sulfide during …
The Association Of Water Quality Parameters, Geological Substrates And Periphyton Community Structure, Richard L. Meyer, Julia Christensen Eichman
The Association Of Water Quality Parameters, Geological Substrates And Periphyton Community Structure, Richard L. Meyer, Julia Christensen Eichman
Technical Reports
This research was designed to understand the structure of epilithic diatom assemblage of a first-to-third order stream system which has minimal variance in nutrient concentration, but significant differences in geomorphological character. The primary objective was to determine the importance of geological substrate on the structure of the diatom assemblages. The second objective was to examine the effect of flow on these assemblages, and the third part of the research was to develop a seasonal model of temporal and spatial annual succession. The temporal and spatial models represent the effect of seasons, stream order, substrate characteristics, storm events, and periods of …
Investigation Of The Relationship Of Earthquakes And Underground Waste Disposal In The El Dorado Area, Arkansas, Randel Cox, Roy B. Vanarsdale
Investigation Of The Relationship Of Earthquakes And Underground Waste Disposal In The El Dorado Area, Arkansas, Randel Cox, Roy B. Vanarsdale
Technical Reports
From December, 1983 to September, 1989 twelve small earthquakes were recorded for the El Dorado, Arkansas area. Magnitudes of these earthquakes were well below damaging levels. Prior to this time no seismicity was reported in the area, suggesting that the earthquakes were not naturally occurring and may have been the result of human activity. El Dorado is located at the margin of a region of underground waste brine disposal and along a major fault zone. Elevated pore pressures resulting from brine disposal may have reduced the normal (locking) stresses across fault surfaces and triggered fault movement. Two injection wells (Great …
Pleistocene Mammals From The South Sulphur River, Hunt County, Texas, Leo Carson Davis, Kenneth M. Ball
Pleistocene Mammals From The South Sulphur River, Hunt County, Texas, Leo Carson Davis, Kenneth M. Ball
Journal of the Arkansas Academy of Science
Preliminary collecting and excavating along the South Sulphur River has produced a diverse list of fossil mammals. The pampathere, Holmesina septentrionalis, and the large armadillo, Dasypus bellus, with their southern affinities from the extinct megafauna, were found in association with Microtus pennsylvanicus, which has a northern distribution at present. This combination of species argues for climatic conditions and biotic communities during the Pleistocene that have no modern counterparts.
Preparation Of A Series Of Substituted N-Phenyl-5-Bromo-6-Chloro- And 5-Bromo-6-Chloronicotinates Of Potential Agricultural Interest, Frank L. Setliff, Maximillia M. Muguluma, Jody Z. Caldwell
Preparation Of A Series Of Substituted N-Phenyl-5-Bromo-6-Chloro- And 5-Bromo-6-Chloronicotinates Of Potential Agricultural Interest, Frank L. Setliff, Maximillia M. Muguluma, Jody Z. Caldwell
Journal of the Arkansas Academy of Science
Substituted phenyl esters of 5-bromo-2-chloronicotinic acid and 5 bromo 6-chloronicotinic acid were prepared. The acids were first converted to their respective acid chlorides using thionyl chloride, and the acid chlorides were immediately transformed to the esters by treatment with the appropriately substituted phenol in sodium hydroxide solution. Aunique chloride displacement of bromide was observed on attempting to convert 5,6-dibromonicotinic acid to its acid chloride
Microwave Pasteurization Of Potting Mixes, Rudolph J. Eichenberger
Microwave Pasteurization Of Potting Mixes, Rudolph J. Eichenberger
Journal of the Arkansas Academy of Science
A study was conducted to determine if potting soils could be pasteurized with a typical 1200 watt microwave oven. Microwave radiation times varied from 0 to 6.0 minutes. Preliminary results indicated that "damping-off" diseases could be prevented in tomato seedlings with the use of potting soils pasteurized by microwaves.