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Full-Text Articles in Physical Sciences and Mathematics

Sediment Phosphorus Flux In Beaver Lake In Northwest Arkansas, Taraf Abu Hamdan, Thad Scott, Duane Wolf, Brian E. Haggard Jan 2010

Sediment Phosphorus Flux In Beaver Lake In Northwest Arkansas, Taraf Abu Hamdan, Thad Scott, Duane Wolf, Brian E. Haggard

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

Internal phosphorus (P) loading may influence primary production in lakes, but the influence of sediment-derived P has not been well studied in Beaver Lake of Northwest Arkansas. Soluble reactive phosphorus (SRP), dissolved organic P (DOP), and total dissolved P (TDP) sediment-water fluxes were determined using intact sediment cores collected from deepwater environments in the riverine, transition zone, and lacustrine zones of Beaver Lake. The SRP, DOP, and TDP fluxes were also estimated from cores collected from shallow locations in the transition zone. There was a net positive SRP (0.001 – 0.005 µg P cm-2 h-1), DOP (0.005 – 0.01 µg …


Assessment Of Total Organic Carbon Concentrations In Two Streams Of Northwest Arkansas: Town Branch And Brush Creek, Abigail N. Washispack, Jason A. Mcginnis, Brian E. Haggard Jan 2010

Assessment Of Total Organic Carbon Concentrations In Two Streams Of Northwest Arkansas: Town Branch And Brush Creek, Abigail N. Washispack, Jason A. Mcginnis, Brian E. Haggard

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

Within a stream, changes in flow rate and local environment can affect the total organic content (TOC) concentrations in the stream water and TOC delivery downstream to water supply reservoirs. Disinfection by-products (DBPs) result from various chemical reactions between chlorine, bromine, and organic carbon in raw water during the drinking water treatment process; DBPs are potential carcinogens and are regulated by the U.S. Environmental Protection Agency. In this project, we measured the TOC concentrations in two streams in the Beaver Lake Watershed: Town Branch and Brush Creek. We then compared TOC concentrations between the two streams and to that observed …


Effects Of Diesel And Biodiesel Blends On Engine Performance And Efficiency, Christopher Hunt, Donald Johnson, Don Edgar Jan 2010

Effects Of Diesel And Biodiesel Blends On Engine Performance And Efficiency, Christopher Hunt, Donald Johnson, Don Edgar

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

Tests were conducted during the summer of 2009 on a John Deere 3203 diesel tractor to determine differences in specific fuel consumption (sfc), power take-off (PTO) torque (Nm), and PTO power (kW), between ultralow sulfur No. 2 Diesel (D2), 20% biodiesel (B20), 50% biodiesel (B50), and100% biodiesel (B100). Four 1-hr tests were conducted with D2, while three 1-hr tests were conducted with B20, B50, and B100. The results indicated that there was no significant (p < 0.05) difference between D2 and B20 for power or torque. Fueling with B50 resulted in significantly lower power and torque than fueling with D2 or B20, but significantly higher power and torque than fueling with B100. There were significant differences between each fuel in sfc; as the biodiesel blend increased, sfc also increased. Based on these data, B20 appears to be the optimal biodiesel blend for this and similar compact utility tractors since fueling with B20 resulted in no significant loss in power or torque (compared to D2) and only a slight increase in fuel consumption.