Bioresource and Agricultural Engineering Commons^™

Side Mounted Doppler Flow Meter For Canals, Stuart W. Styles

BioResource and Agricultural Engineering

The Irrigation Training and Research Center has undertaken a performance review of advanced electronic flow measurement technologies in irrigation applications. An example is the SonTek Argonaut Side-Looking (SL) Doppler Flow Meter.

Doppler Flow Meters For Turnouts, Stuart W. Styles

BioResource and Agricultural Engineering

Irrigation districts, farmers and other agricultural and environmental water users need reliable and low-cost flow meters with integrated dataloggers to measure water velocity and depth with a high level of precision. The Irrigation Training and Research Center has undertaken a performance review of advanced electronic flow measurement technologies in irrigation applications. Examples are the Unidata STARFLOW and the MACE AgriFlo Ultrasonic Doppler Meters.

Variable Frequency Drives - Planning Your System, Charles M. Burt

BioResource and Agricultural Engineering

Many irrigation districts are installing Variable Frequency Drives (VFDs) to increase their level of service to their customers and/or to reduce their energy consumption. This brochure is intended to help irrigation districts properly evaluate what type of VFD they need and how to install it.

However, not all VFDs are the same. The performance quality of a VFD will depend on the characteristics of the particular VFD, as well as how the VFD system is set up. Many times it is the seemingly small details that will have a large impact on performance in the long run. This brochure is …

Ft-Nir Spectroscopic Analysis Of Nitrogen In Cotton Leaves, Mark R. Riley, Loreto C. Canaves

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Near-infrared spectroscopy was evaluated as a means to quantify the nitrogen content- in fresh cotton leaves (Gossypium hirsutum L. var. Delta Pine 90) subjected to a factorial design experiment of varying nitrogen and water applications. Absorbance spectra were collected in the 10000-4000 cm^-1 (1000-2500 nm) region from fresh cotton leaves over a two month portion of the growing season. Total nitrogen content was quantified by a wet chemistry Kjeldahl method for validation purposes. Partial least-squares regression analysis, using an automated grid search method, selected the spectral region 6041 to 5651 cm^-1 (1650-1770 nm) for analysis based on having …

Biomineralization Of Poorly Crystalline Fe(Iii) Oxides By Dissimilatory Metal Reducing Bacteria (Dmrb), John M. Zachara, Ravi K. Kukkadapu, James K. Fredrickson, Yuri A. Gorby, Steven C. Smith

United States Department of Energy: Publications

Dissimilatory metal reducing bacteria (DMRB) catalyze the reduction of Fe(III) to Fe(II) in anoxic soils, sediments, and groundwater. Two-line ferrihydrite is a bioavailable Fe(III) oxide form that is exploited by DMRB as a terminal electron acceptor. A wide variety of biomineralization products result from the interaction of DMRB with 2-line ferrihydrite. Here we describe the state of knowledge on the biotransformation of synthetic 2-line ferrihydrite by laboratory cultures of DMRB using select published data and new experimental results. A facultative DMRB is emphasized (Shewanella putrefaciens) upon which most of this work has been performed. Key factors controlling the identity of …

Reduction Kinetics Of Fe(Iii), Co(Iii), U(Vi), Cr(Vi), And Tc(Vii) In Cultures Of Dissimilatory Metal-Reducing Bacteria, Chongxuan Liu, Yuri A. Gorby, John M. Zachara, James K. Fredrickson, Christopher F. Brown

United States Department of Energy: Publications

The reduction kinetics of Fe(III)citrate, Fe(III)NTA, Co(III)EDTA⁻, U(VI)O₂²⁺, Cr(VI)O₄²⁻, and Tc(VII)O₄⁻ were studied in cultures of dissimilatory metal reducing bacteria (DMRB): Shewanella alga strain BrY, Shewanella putrefaciens strain CN32, Shewanella oneidensis strain MR-1, and Geobacter metallireducens strain GS-15. Reduction rates were metal specific with the following rate trend: Fe (III)citrate ≥ Fe(III)NTA > Co(III)EDTA⁻ ›› UO₂ ²⁺ > CrO₄²⁻ > TcO₄⁻, except for CrO₄²⁻ when H₂ was used as electron donor. The metal reduction rates were also electron donor dependent with faster rates …

Influence Of Mn Oxides On The Reduction Of Uranium(Vi) By The Metal-Reducing Bacterium Shewanella Putrefaciens, James K. Fredrickson, John M. Zachara, David Kennedy, Chongxuan Liu, Martine Duff, Douglas Hunter, Alice Dohnalkova

United States Department of Energy: Publications

The potential for Mn oxides to modify the biogeochemical behavior of U during reduction by the subsurface bacterium Shewanella putrefaciens strain CN32 was investigated using synthetic Mn(III/IV) oxides (pyrolusite [β-MnO₂], bixbyite [Mn₂O₃] and K⁺-birnessite [K₄Mn₁₄O₂₇ • 8H₂O]). In the absence of bacteria, pyrolusite and bixbyite oxidized biogenic uraninite (UO₂[s]) to soluble U(VI) species, with bixbyite being the most rapid oxidant. The Mn(III/IV) oxides lowered the bioreduction rate of U(VI) relative to rates in their absence or in the presence of gibbsite …

Sorption Of Cs+ To Micaceous Subsurface Sediments From The Hanford Site, Usa, John M. Zachara, Steven Smith, Chongxuan Liu, James Mckinley, R. Jeffrey Serne, Paul Gassman

United States Department of Energy: Publications

The sorption of Cs⁺ was investigated over a large concentration range (10^-9–10^-2 mol/L) on subsurface sediments from a United States nuclear materials site (Hanford) where high-level nuclear wastes (HLW) have been accidentally released to the vadose zone. The sediment sorbs large amounts of radiocesium, but expedited migration has been observed when HLW (a NaNO₃ brine) is the carrier. Cs⁺ sorption was measured on homoionic sediments (Na⁺, K⁺, Ca²⁺) with electrolyte concentrations ranging from 0.01 to 1.0 mol/L. In Na⁺ electrolyte, concentrations were extended to near saturation with …

Extraction Of Silymarin Compounds From Milk Thistle (Silybum Marianum) Seed Using Hot, Liquid Water As The Solvent, J.F. Alvarez Barreto

Inquiry: The University of Arkansas Undergraduate Research Journal

High value specialty chemicals are usually obtained from natural products by extracting with generally regarded as safe (GRAS) solvents. Because organic solvents are quite often used, high operating and disposal costs often occur. When compared to traditional solvents, water can be viewed as an interesting alternative because of its low operating and disposal costs. Milk thistle contains compounds (taxifolin, silychristin, silydianin, silybinin A and silybinin B) that display hepatoxic protection properties. This paper examines the batch extraction of silymarin compounds from milk thistle seed meal in 50'C, 70'C, 85'C and 100'C water as a function of time. For taxifolin, silychristin, …

Fiber Optic Sensor Response To High Levels Of Fat In Cream, Czarena L. Crofcheck, Frederick A. Payne, Clair L. Hicks, M. Pinar Mengüç, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

A light backscatter technique using optical fibers to deliver and receive light was investigated for measuring the milkfat content of unhomogenized cream. Light backscatter through cream at wavelengths of 450 to 900 nm was measured for fiber separation distances from 2 to 6.5 mm and for cream containing 10 to ~40 weight percent (wt%) milkfat. Unhomogenized cream (~40 wt% milkfat) was mixed with skim milk (~0.05 wt% milkfat) to yield samples with five different milkfat levels. Three optical response models were tested for correlation with milkfat content: one using the light intensity measurement at a single separation distance, the second …