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Articles 1 - 13 of 13
Full-Text Articles in Physical Sciences and Mathematics
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- …
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
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.
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.
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 …
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.
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
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 …
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.
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.
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.
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 …
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 …