Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Chemistry (7)
- Organic Chemistry (6)
- Physics (4)
- Engineering Physics (3)
- Life Sciences (3)
-
- Biochemistry (2)
- Biochemistry, Biophysics, and Structural Biology (2)
- Engineering (2)
- Astrophysics and Astronomy (1)
- Computer Sciences (1)
- Cosmology, Relativity, and Gravity (1)
- Earth Sciences (1)
- Electrical and Computer Engineering (1)
- Electromagnetics and Photonics (1)
- Entomology (1)
- Environmental Chemistry (1)
- Fluid Dynamics (1)
- Fresh Water Studies (1)
- Geology (1)
- Materials Science and Engineering (1)
- Numerical Analysis and Scientific Computing (1)
- Oceanography and Atmospheric Sciences and Meteorology (1)
- Other Astrophysics and Astronomy (1)
- Other Physics (1)
- Physical Chemistry (1)
- Programming Languages and Compilers (1)
- Semiconductor and Optical Materials (1)
- Stratigraphy (1)
Articles 1 - 15 of 15
Full-Text Articles in Physical Sciences and Mathematics
Boron Phosphate And Aluminum Phosphate Aerogels, David A. Lindquist, Steven M. Poindexter, Sterling S. Rooke, D. Ritchie Stockdale, Kirk B. Babb, Alison L. Smoot, William E. Young
Boron Phosphate And Aluminum Phosphate Aerogels, David A. Lindquist, Steven M. Poindexter, Sterling S. Rooke, D. Ritchie Stockdale, Kirk B. Babb, Alison L. Smoot, William E. Young
Journal of the Arkansas Academy of Science
Anhydrous sol-gel condensation of triethyl phosphate [(CH3CH2O)3PO] with boron trichloride (BCL3 ) or triethyl aluminum [(CH3CH2 ) 3A1] in organic solvents, led to formation of metallophosphate gels. The pore fluid of the gels was removed under supercritical conditions in a pressurized vessel to form aerogels. The aerogels were then calcined at progressively higher temperatures to produce high surface area phosphates. Since the initial gel reagent mixtures contained several NMR active nuclei, the condensation chemistry prior to the gel point was monitored by solution nB NMR. The surface areas, distribution of pore sizes, and total pore volumes of the aerogel products …
Hammett Correlations Of Half-Wave Reduction Potentials In A Series Of N-(Aryl Substituted)-Dichloronicotinamides, Cecil C. Persons, Ali U. Shaikh, Julie Shiflett, Frank L. Setliff
Hammett Correlations Of Half-Wave Reduction Potentials In A Series Of N-(Aryl Substituted)-Dichloronicotinamides, Cecil C. Persons, Ali U. Shaikh, Julie Shiflett, Frank L. Setliff
Journal of the Arkansas Academy of Science
Excellent correlations of Hammett substituent constants (sigmaR) of a series of N-(R-substituted aryl) -2,6-, 2,5-, and 5,6- dichloronicotinamides with polarographic half-wave potentials were observed. Although the correlations demonstrate that all three series of amides experience comparable sensitivity to the R groups at the carbonyl reduction site, the relative ease of reduction varies according to the chlorine substitution pattern on the pyridine ring. These differences are suggested to be due to combinations of mesomeric, inductive, and field effects which operate differently in the three systems. Correlation analysis also revealed that Hammett heteroatomic replacement constants previously determined by NMR studies are valid …
Storm Dominated Channel Sequences On A Shallow Marine Shelf: Morrowan Of Northwest Arkansas, Kimberley R. Jones, Doy L. Zachry
Storm Dominated Channel Sequences On A Shallow Marine Shelf: Morrowan Of Northwest Arkansas, Kimberley R. Jones, Doy L. Zachry
Journal of the Arkansas Academy of Science
The Brentwood Member of the Bloyd Formation (Morrowan, Pennsylvanian) in northwestern Arkansas contains stratigraphic sequences deposted by tropical storms in middle shelf environments. The deposits are confined to shallow channels incised by strong unidirectional currents into an interval of shale deposited during fair weather conditions. Complete storm sequences reflect initial bottom currents of high competency that declined through time and were succeeded by wave generated oscillatory activity. The storm succession consists of an erosion surface followed by a basal pebble conglomerate, massive grainstone and packstone, whole-fossil wackestone, hummocky cross-strata and a swell lag of platy crinoidcalyxes. As storm activity ceased, …
Computational Fluid Dynamics In Small Airway Models Of The Human Lung, G. Burnside, J. R. Hammersley, Rama N. Reddy, B. Catlin
Computational Fluid Dynamics In Small Airway Models Of The Human Lung, G. Burnside, J. R. Hammersley, Rama N. Reddy, B. Catlin
Journal of the Arkansas Academy of Science
The promise of gene replacement therapy for cystic fibrosis, the administration of drugs via inhalation therapy, and die deposition location of man-made airborne particulates all involve a more complete understanding of the fluid dynamics in the human lung. Flow in the larger airways may be measured through life-sized models directly, but the airways in the peripheral lung are too small and the flows are too complex to be studied in this manner. Computational models can be developed which will accurately represent both the geometric nature of the central airways and the fluid dynamics with in them. Two-dimensional and three-dimensional models …
Visualizing Electrostatic Phenomena Using Mathematica, Eric Mayes
Visualizing Electrostatic Phenomena Using Mathematica, Eric Mayes
Journal of the Arkansas Academy of Science
A set of packages for visualizing electrostatic phenomena was developed using Mathematica as a programming language. These packages allow users to plot potential fields, equipotential lines, 2-D and 3-D vector fields in order to gain a visual understanding of electrostatic charges. They would be useful in accompanying undergraduate physics labs pertaining to electrostatics, as they would enable students to connect experiment with mathematics through open-ended visual exploration
Aquatic Macrophytes Of Two Small Northwest Arkansas Reservoirs, John J. Sullivan, Arthur V. Brown
Aquatic Macrophytes Of Two Small Northwest Arkansas Reservoirs, John J. Sullivan, Arthur V. Brown
Journal of the Arkansas Academy of Science
Lake Fayetteville and Lake Wedington are small reservoirs of about the same size and age that are located in northwestern Arkansas. We collected macrophytes from eleven transects around each reservoir in the autumn of 1993. Justicia (waterwillow), Typha (cat-tail), Scirpus (bulrush), Potamogeton (pondweed), and Zannichellia (horned pondweed) occur in both reservoirs. Justicia occurs most commonly in both reservoirs. The macrophytes of Lake Wedington are organized in a characteristic zonation pattern with bands from shore toward open water of emergent, floating-leaved, then submersed macrophytes. Macrophyte zonation was not as evident in Lake Fayetteville because of the low occurrence of floating leaved …
Monte Carlo Simulation Of The Scintillating Optical Fiber Calorimeter (Sofcal), Zibin Yang, Russell Gillum, Donald C. Wold
Monte Carlo Simulation Of The Scintillating Optical Fiber Calorimeter (Sofcal), Zibin Yang, Russell Gillum, Donald C. Wold
Journal of the Arkansas Academy of Science
A scintillating optical fiber calorimeter (SOFCAL) is being developed by NASA/Marshall Space Flight Center for use in balloon-borne emulsion chambers to study the spectrum of high-energy cosmic rays and gamma rays. SOFCAL will not saturate for long exposures, and the detector will be helpful for the study of primary cosmic-ray nuclei energies from 100 GeV to 1,000 TeV. For a given incident particle and energy, computer simulations of electromagnetic cascades allow computation of energy deposited in different regions of the calorimeter. For these initial simulations, a 5-cm x 5-cm x 7-cm calorimeter was used. Each subsection contained a 0.4-cm thick …
Using The Cern Program-Library Graphics And Interactive Data Display, Morgan T. Burks, Wilson H. Howe, Christine A. Byrd, Wilfred J. Braithwaite
Using The Cern Program-Library Graphics And Interactive Data Display, Morgan T. Burks, Wilson H. Howe, Christine A. Byrd, Wilfred J. Braithwaite
Journal of the Arkansas Academy of Science
Small scale Monte Carlo programming is growing rapidly due to the ease with which complex problems may be formulated by any programmer. These programmers may choose to exploit graphics and interactive displays available in the program library developed and maintained by CERN (the Center for European Nuclear Research). This paper outlines the use of graphics and interactive data display features of the CERN program library, developed for visualizing simulated data events in particle detectors. One example uses GEANT, CERN's Monte Carlo modeling program, to simulate 300 MeV/c protons incident on a silicon slab. Display packages for GEANT are available both …
Reaction Of Titanocene Dichloride With Acetylenedicarboxylate, Tanya L. Hagler, Mark Draganjac, Paul M. Nave, J. Ed Bennett, Farooq Kahn, Robert Engelken, Gerard Williams, Chris Poole, Kwok Fai Yu
Reaction Of Titanocene Dichloride With Acetylenedicarboxylate, Tanya L. Hagler, Mark Draganjac, Paul M. Nave, J. Ed Bennett, Farooq Kahn, Robert Engelken, Gerard Williams, Chris Poole, Kwok Fai Yu
Journal of the Arkansas Academy of Science
The reaction of Cp2TiCl2 with either the mono- or dipotassium salt of acetylenedicarboxylic acid (ADC) gives high yields of an insoluble orange product. The insoluble compound shows potential semiconductor behavior, as evidenced by an apparent bandgap in the orange region of the visible spectrum. Under N2 ,the compound decomposes at 238° C, eventually losing approximately 46% total mass up to 1350° C. The exothermic decomposition in air, beginning at 235° C, results in the formation of titanium oxides.
Analysis Of Ammunition By X-Ray Fluorescence, Michael W. Rapp, Teddy L. Townsend
Analysis Of Ammunition By X-Ray Fluorescence, Michael W. Rapp, Teddy L. Townsend
Journal of the Arkansas Academy of Science
Nondestructive analysis of lead shotgun pellets by X-ray fluorescence (XRF) shows considerable promise in assignment of the identity of the ammunition source. X-ray fluorescence spectra of various shotgun pellets and of standard alloys were obtained using an energy-dispersive instrument and an Am-241 source. The correlation obtained between the precent antimony in the standard alloys and the intensity of the Ka fluorescence peak from antimony was excellent. Peak areas from antimony in shotgun pellets were measured and compared to calibration plots from the standard alloys. The method was capable of distinguishing among lead-based alloys, such as ammunition, with antimony content as …
Thermal Decomposition Studies Of Selected Transition Metal Polysulfide Complexes. Ii. Effect Of Atmosphere On Decomposition, Benjamin Rougeau, Mark Draganjac
Thermal Decomposition Studies Of Selected Transition Metal Polysulfide Complexes. Ii. Effect Of Atmosphere On Decomposition, Benjamin Rougeau, Mark Draganjac
Journal of the Arkansas Academy of Science
Initial studies involved the thermal decomposition profile of five polysulfide complexes in air up to 550 °C. Since our first report to the Academy in 1990, we have obtained the capability to run samples up to 1500°C under various gases. Thermal Gravimetric Analysis (TGA) and Differential Thermal Analysis (DTA)of a series of transition metal polysulfide complexes are presented. Compounds analyzed included Cp2TiS5 ,MoS9 2",MoOS8 2", Zn(S x ) 2", Cd(S x ) 2-, Fe2S122 - and NiS82.
Fluid Dynamics Model Of Data Acquisition And Date Analysis For High-Energy Physics, Charles M. Byrd, Christine A. Byrd, Wilson H. Howe, W. J. Braithwaite
Fluid Dynamics Model Of Data Acquisition And Date Analysis For High-Energy Physics, Charles M. Byrd, Christine A. Byrd, Wilson H. Howe, W. J. Braithwaite
Journal of the Arkansas Academy of Science
No abstract provided.
Ultrasound Assisted Oxidative Cleavage Of Alpha-Keto, Alpha-Hydroxy And Alpha-Halo Ketones By Superoxide, Yi Hong Cao, A. Toland, Dominic T.C. Yang
Ultrasound Assisted Oxidative Cleavage Of Alpha-Keto, Alpha-Hydroxy And Alpha-Halo Ketones By Superoxide, Yi Hong Cao, A. Toland, Dominic T.C. Yang
Journal of the Arkansas Academy of Science
No abstract provided.
Effective, Reliable, Inexpensive Cryofixation Device, Lawrence A. Mink, Roger A. Buchanan
Effective, Reliable, Inexpensive Cryofixation Device, Lawrence A. Mink, Roger A. Buchanan
Journal of the Arkansas Academy of Science
No abstract provided.
Compton Scattering Of Gamma-Rays From Electrons In Advanced Laboratory, Christine A. Byrd, Morgan T. Burks, Lawrence A. Yates, Wilfred J. Braithwaite
Compton Scattering Of Gamma-Rays From Electrons In Advanced Laboratory, Christine A. Byrd, Morgan T. Burks, Lawrence A. Yates, Wilfred J. Braithwaite
Journal of the Arkansas Academy of Science
A kinematically-complete 2-body final state measurement of Compton scattering of 662-keV photons is presened, where both scattered photon energy and electron recoil energy are measured versus photon scattering angle, theta gamma. Passive collimation of the photon beam is avoided; each recoiling electron triggers a photon-scattering event providing active beam collimation. Recoiling electrons have low energies at small theta gamma, impairing electron detection efficiency. Examining the recoiling-electron energy spectra in coincidence with high-resolution gammas indicates a 1"x 1"NaI detector is superior to a 1"x1" NE-102 plastic scintillator as the active scattering material, for efficient recoil-electron detection. Electron efficiencies versus theta gamma …