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Engineering Commons™

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

2001

University of Kentucky

Bioresource and Agricultural Engineering

Articles 1 - 6 of 6

Full-Text Articles in Engineering

Monitoring Subsurface Drainage Flow At Remote Locations, Stephen R. Workman, Stephen F. Higgins, Scott A. Shearer Nov 2001

Monitoring Subsurface Drainage Flow At Remote Locations, Stephen R. Workman, Stephen F. Higgins, Scott A. Shearer

Biosystems and Agricultural Engineering Faculty Publications

Laboratory evaluations and field results are presented for a slotted weir used to measure discharge from subsurface drains. The head–discharge curve for the vertical slot is a simple power function with an exponent of 1.5. There was excellent agreement (r2 > 0.99 and 1:1 slope) between predicted and observed discharge in laboratory testing of 12 test weirs representing five slot widths. The primary advantages of the vertical slot weir are its simplicity, ease of maintenance, and ability to measure small flow rates. Disadvantages include a tendency for the slot to close a small amount over time as a result of …

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Determining Matric Stress With The Modified Cam Clay Energy Relationship, Richard A. Rohlf, Larry G. Wells Sep 2001

Determining Matric Stress With The Modified Cam Clay Energy Relationship, Richard A. Rohlf, Larry G. Wells

Biosystems and Agricultural Engineering Faculty Publications

The stress generated by matric suction, or matric stress, was determined at points along the stress path with an analytical and experimental procedure based on the modified Cam clay energy relationship. Matric stress was found to be approximately constant at large strain for constant water content triaxial compression tests. Matric stress was included in both shear and volume relationships in a critical–state soil model that employed the modified Cam clay yield function. Shear was modeled with a constant matric stress. Slope of the normal compression and recompression lines was adjusted for matric stress using a state function that expressed matric …

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Evaluation Of Residual Chlorothalonil Levels On Processing Tomato Foliage Using The Tom-Cast Spray Program, Jane M. Patterson, Sue E. Nokes, Mark A. Bennett, Richard E. Riedel Jul 2001

Evaluation Of Residual Chlorothalonil Levels On Processing Tomato Foliage Using The Tom-Cast Spray Program, Jane M. Patterson, Sue E. Nokes, Mark A. Bennett, Richard E. Riedel

Biosystems and Agricultural Engineering Faculty Publications

Field tomatoes were sprayed with chlorothalonil on a fixed–interval spray program and a TOM–CAST spray program with disease severity value threshold of 18. Foliage samples from upper and lower canopy layers were collected prior to spray re–applications. Chlorothalonil residue data were compared to the chlorothalonil efficacy threshold (1.2 μg/cm2). Using a seven–day interval program, eight of the nine and seven of the nine spray intervals had chlorothalonil residues above the critical level for the upper and lower canopy layers, respectively. Using the TOM–CAST program, four of the five spray intervals had chlorothalonil residues above the critical level for …

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Influence Of Inoculum Size On Phytase Production And Growth In Solid-State Fermentation By Aspergillus Niger, Chundakkadu Krishna, Sue E. Nokes Jul 2001

Influence Of Inoculum Size On Phytase Production And Growth In Solid-State Fermentation By Aspergillus Niger, Chundakkadu Krishna, Sue E. Nokes

Biosystems and Agricultural Engineering Faculty Publications

Solid–state fermentation is experiencing renewed interest for industrial enzyme production. Previous studies on the effects of fungal inoculum size on product yield have focused on spore inoculum. However, some organisms require vegetative inocula. This study investigated the effects of initial inoculum colony age, vegetative inoculum size, and duration of fermentation on the production of fungal biomass and phytase in solid–state fermentation using Aspergillus niger grown on wheat bran and soy meal. Initial inocula from 7– and 14–day–old potato dextrose agar (PDA) plates were used to study the effect of inoculum colony age in liquid culture and its further influence on …

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Submerged And Solid-State Phytase Fermentation By Aspergillus Niger: Effects Of Agitation And Medium Viscosity On Phytase Production, Fungal Morphology And Inoculum Performance, Maria Papagianni, Sue E. Nokes, Keith Filer Jan 2001

Submerged And Solid-State Phytase Fermentation By Aspergillus Niger: Effects Of Agitation And Medium Viscosity On Phytase Production, Fungal Morphology And Inoculum Performance, Maria Papagianni, Sue E. Nokes, Keith Filer

Biosystems and Agricultural Engineering Faculty Publications

Qualitative relationships between agitation levels and medium viscosity, Aspergillus niger morphology and phytase production were investigated in submerged and solid-state fermentations. Overall phytase production increased with increasing shaker speeds from 150 to 300 rpm, although specific growth rates and phytase production rates were higher at 150 rpm for 72 h from inoculation. Fungal morphology was greatly influenced by agitation with the morphological forms of small pellets and entangled mycelia predominating at 150 rpm, while the free filamentous form was obtained at 300 rpm. Upon inoculation of SSF, increased productivities were obtained from inocula grown at 150 rpm. A shift towards …

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Non–Water–Stressed Baseline As A Tool For Dynamic Control Of A Misting System For Propagation Of Poinsettias, Sérgio Zolnier, Richard S. Gates, Robert G. Anderson, Sue E. Nokes, George A. Duncan Jan 2001

Non–Water–Stressed Baseline As A Tool For Dynamic Control Of A Misting System For Propagation Of Poinsettias, Sérgio Zolnier, Richard S. Gates, Robert G. Anderson, Sue E. Nokes, George A. Duncan

Biosystems and Agricultural Engineering Faculty Publications

A technique is presented for dynamically adjusting misting intervals during propagation of vegetative cuttings. A crop setpoint temperature for activation of misting was defined by a "non-water-stressed baseline" concept, using infrared thermometry to acquire canopy temperature for plant feedback. The critical crop setpoint temperature was calculated from instantaneous values of air temperature, incident radiation, and air vapor pressure deficit (VPDair). Misting was activated when the actual crop temperature exceeded the critical crop setpoint temperature. The dynamic control was shown to have the potential to reduce the amount of applied water from 9 to 12 times during low levels …

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