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Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

2007

Journal

University of Arkansas, Fayetteville

Articles 1 - 6 of 6

Full-Text Articles in Physical Sciences and Mathematics

Comparison Of Aquatic-Insect Habitat And Diversity Above And Below Road Crossings In Low-Order Streams, J. Wesley Neal, Nathan J. Harris, Sathyanand Kumaran, David A. Behler, Thomas J. Lang, Paul R. Port, Marcella Melandri, Benjamin G. Batten Jan 2007

Comparison Of Aquatic-Insect Habitat And Diversity Above And Below Road Crossings In Low-Order Streams, J. Wesley Neal, Nathan J. Harris, Sathyanand Kumaran, David A. Behler, Thomas J. Lang, Paul R. Port, Marcella Melandri, Benjamin G. Batten

Journal of the Arkansas Academy of Science

The effects of road crossings on fish communities have been extensively studied; yet little attention has been given to macroinvertebrate communities. This study evaluated physical stream characteristics, water quality, and aquatic-insect richness from above and below road crossings of low-order streams in the Ouachita National Forest in Arkansas. Fifteen road crossings were sampled during October and November 2005. Erosion was significantly higher below road crossings than above. Sites downstream of road crossings had significantly lower pH and significantly higher turbidity than sites upstream of road crossings. Despite differences in water quality and habitat, there was no apparent difference in aquatic-insect …

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Improvement To The Data Logging Capability Of A Cough Monitoring System, Matthew Barlow Jan 2007

Improvement To The Data Logging Capability Of A Cough Monitoring System, Matthew Barlow

Inquiry: The University of Arkansas Undergraduate Research Journal

Data logging capability of a previously developed self contained cough recorder using an accelerometer as the sensing element is improved by using a secure digital memory card for later retrieval on a computer. Firmware is developed to enhance the functionality of the cough recorder. Existing libraries are modified for increased write rates. Increased writing speed allows 8-bit sampling at rates exceeding 8kHz, allowing for detailed time and frequency domain analysis. Additional features have also been developed to enable easy management of recordings, such as a file system compatibility with Microsoft Windows., and unique file names for each recording.

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Pto Performance And Nox Emissions With D2, B20, And B100 Fuels In A John Deere 3203 Compact Tractor, Matthew Hardin, Tonya Brown, Melanie Roller, Donald Johnson, George Wardlow Jan 2007

Pto Performance And Nox Emissions With D2, B20, And B100 Fuels In A John Deere 3203 Compact Tractor, Matthew Hardin, Tonya Brown, Melanie Roller, Donald Johnson, George Wardlow

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Tests were conducted in fall 2006 on a John Deere 3203 diesel tractor to determine differences in specific fuel consumption, power take-off (PTO) torque, PTO power, thermal efficiency, and oxides of nitrogen (NOx) emissions between No. 2 diesel (D2), 20% biodiesel (B20), and 100% biodiesel (B100). Four 1-hour tests were conducted on each fuel. The results indicated no statistically significant differences (p≤.05) between D2 or B20 on any variable of interest. However, B100 resulted in significantly (p≤.05) increased, specific fuel consumption and thermal efficiency and decreased PTO torque and PTO power over both D2 and B20. These data suggest that …

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Quantifying Soil Chemical Properties Using Near Infrared Reflectance Spectroscopy, Robert L. Ficklin, Shane M. Foley, Robert E. Kissell Jr. Jan 2007

Quantifying Soil Chemical Properties Using Near Infrared Reflectance Spectroscopy, Robert L. Ficklin, Shane M. Foley, Robert E. Kissell Jr.

Journal of the Arkansas Academy of Science

Methodologies for determining soil chemical properties have evolved dramatically during the past century. Early geochemical analyses were conducted exclusively through the use of wet chemistry techniques that were relatively reliable but painstaking and subject to errors at various stages of analysis. Near infrared reflectance spectroscopy (NIRS) has emerged as a new approach for rapidly analyzing a variety of materials including soils. In this study soil samples were taken from eight study areas across the Ozark Highlands of Arkansas, and NIRS calibration models were developed to determine the accuracy of using NIRS to analyze soils compared with standard soil chemical analysis …

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Measurement And Modeling Of Light Transmission Through Turbid Media, Alois (Al) J. Adams, Michael Fahrenwald, Long Do Jan 2007

Measurement And Modeling Of Light Transmission Through Turbid Media, Alois (Al) J. Adams, Michael Fahrenwald, Long Do

Journal of the Arkansas Academy of Science

No abstract provided.

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Electron Shock Waves: Ionization Rate And Solutions To The Efd Equations, Mostafa Hemmati, Steven Summers, Michael Weller Jan 2007

Electron Shock Waves: Ionization Rate And Solutions To The Efd Equations, Mostafa Hemmati, Steven Summers, Michael Weller

Journal of the Arkansas Academy of Science

This paper describes our numerical investigation into ionizing breakdown waves, primarily antiforce waves. Antiforce waves are waves for which the electric field force on the electronsisin the opposite direction of the wave's propagation. This investigation required us to utilize one-dimensional electron fluid-dynamical equations, which were applied to a pulse wave that transmits into a region of neutral gas and is under the influence of an applied electric field. Two important assumptions were made in applying these equations: electrons were considered to be the main component in the propagation of the pulse wave, and the partial pressure of the electron gas …

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