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University of Nebraska - Lincoln

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Articles 511 - 540 of 697

Full-Text Articles in Biomedical Engineering and Bioengineering

Construction Of A Derivative Of Agrobacterium Tumefaciens C58 That Does Not Mutate To Tetracycline Resistance, Zhao-Qing Luo, Thomas E. Clemente, Stephen K. Farrand Jan 2001

Construction Of A Derivative Of Agrobacterium Tumefaciens C58 That Does Not Mutate To Tetracycline Resistance, Zhao-Qing Luo, Thomas E. Clemente, Stephen K. Farrand

Nebraska Center for Biotechnology: Faculty and Staff Publications

Agrobacterium tumefaciens C58 mutates to tetracycline resistance at high frequency, complicating the use of many broad-host-range cloning and binary vectors that code for resistance to this antibiotic as the selection marker. Such mutations are associated with a resistant gene unit, tetC58, that is present in the genome of this strain. By deleting the tetC58 locus, we constructed NTL4, a derivative of C58 that no longer mutates to tetracycline resistance. The deletion had no detectable effect on genetic or physiological traits of NTL4 or on the ability of this strain to transform plants.

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Tillage And Fallow Effects On Selected Soil Quality Characteristics Of Former Conservation Reserve Program Sites, John E. Gilley, John W. Doran, Bahman Eghball Jan 2001

Tillage And Fallow Effects On Selected Soil Quality Characteristics Of Former Conservation Reserve Program Sites, John E. Gilley, John W. Doran, Bahman Eghball

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Tillage and fallow have been suggested as management options for converting Conservation Reserve Program (CRP) areas to cropland. This study was conducted to measure selected soil quality characteristics of former CRP sites in Mississippi, Nebraska, and South Dakota that were tilled and then left fallow for 21 or 22 months. Soil samples from depth intervals of 0-7.6 cm and 0-30.5 cm were collected for laboratory assessment of the following soil quality indicators: bulk density, EC, pH, total C, organic C, total N, NO3-N, NH4-N, PO4-P, biomass C, biomass N, anaerobic NH4-N, lab …

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Phosphorus Risk Assessment Index Evaluation Using Runoff Measurements, Bahman Eghball, John E. Gilley Jan 2001

Phosphorus Risk Assessment Index Evaluation Using Runoff Measurements, Bahman Eghball, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

An index to evaluate the phosphorus (P) pollution potential of agricultural fields was proposed by Lemunyon and Gilbert in 1993. Data from three rainfall simulation studies were used to evaluate the relative importance of the variables in the P index. These studies included plots containing sorghum (Sorghum bicolor L.), winter wheat (Triticum aestivum L.), and corn (Zea mays L.) residues on which chemical fertilizer and composted or noncomposted beef cattle feedlot manure were applied under no-till and disked conditions. The factors of erosion, runoff, soil P level P application source, and method, and rate of P addition …

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Reducing Long-Term Atrazine Runoff From South Central Nebraska, Walter Scott Gorneau, Thomas G. Franti, Brian L. Benham, Steve D. Comfort Jan 2001

Reducing Long-Term Atrazine Runoff From South Central Nebraska, Walter Scott Gorneau, Thomas G. Franti, Brian L. Benham, Steve D. Comfort

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Heavy reliance on chemical weed control in field crops of South Central Nebraska has resulted in the appearance of atrazine at concentrations greater than established drinking water standards. Our objective was to evaluate the best management practices for atrazine runoff for the tillage and herbicide management practices common to the region under study. Field experiments were performed to measure edge–of–field atrazine and water loss from disk–till, ridge–till, and slot plant (no–till) management systems. Results indicated less water runoff from no–till (34% less) and ridge–till (36% less) than from disk–till. Similarly, atrazine loss was also less: 24% less for no–till and …

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Application Of Fuzzy Logic In Automated Cow Status Monitoring, R. M. De Mol, Wayne Woldt Jan 2001

Application Of Fuzzy Logic In Automated Cow Status Monitoring, R. M. De Mol, Wayne Woldt

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Sensors that measure yield, temperature, electrical conductivity of milk, and animal activity can be used for automated cow status monitoring. The occurrence of false-positive alerts, generated by a detection model, creates problems in practice. We used fuzzy logic to classify mastitis and estrus alerts; our objective was to reduce the number of false-positive alerts and not to change the level of detected cases of mastitis and estrus. Inputs for the fuzzy logic model were alerts from the detection model and additional information, such as the reproductive status. The output was a classification, true or false, of each alert. Only alerts …

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Runoff And Soil Loss As Affected By The Application Of Manure, John E. Gilley, L. Mark Risse Nov 2000

Runoff And Soil Loss As Affected By The Application Of Manure, John E. Gilley, L. Mark Risse

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Manure has been used effectively to improve crop production and soil properties because it contains nutrients and organic matter. While it is generally accepted that the improved soil properties associated with manure application lead to changes in runoff and soil erosion, few studies have quantified these impacts. Water quality models used to assess watershed management and estimate total maximum daily load must accurately predict loading rates from fields where manure has been applied. This study was conducted to assemble and summarize information quantifying the effects of manure application on runoff and soil loss resulting from natural precipitation events, and to …

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A Statewide Educational Program To Implement Comprehensive Nutrient Management Planning, Richard K. Koelsch, Charles A. Shapiro, R. Wozniak Sep 2000

A Statewide Educational Program To Implement Comprehensive Nutrient Management Planning, Richard K. Koelsch, Charles A. Shapiro, R. Wozniak

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

EPA and USDA NRSC have stated that the most effective way for animal feeding operations (AFO's) to minimize water quality and public health risks is to develop and implement comprehensive nutrient management plans. In response a proposed CNMP workbook has been designed to serve as an animal operation's environmental operating plan. This project will initiate field testing of the proposed Nebraska CNMP with livestock producers and advisors. It will also assist with development of supporting resources and training for educational and technical advisors.

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Fuzzy Composite Programming To Combine Remote Sensing And Crop Models For Decision Support In Precision Crop Management, David D. Jones, E. M. Barnes Sep 2000

Fuzzy Composite Programming To Combine Remote Sensing And Crop Models For Decision Support In Precision Crop Management, David D. Jones, E. M. Barnes

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Precision crop management is by definition a multi-objective decision-making process that must incorporate a diversity of data, opinion, preference and objective. This paper details an approach to decision making that allows users to express individual or corporate values and preferences; highlights the degree of imprecision associated with each input; highlights the degree of imprecision associated with each alternative; facilitates structuring of the decision process; reduces several levels of complex information into a single chart; allows examination of trade-off between alternatives and interests; and forces examination of inter-relationships between interest. The addition of using remote sensing data provides an efficient method …

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Phototrophic Anaerobic Lagoons As Affected By Copper And Zinc In Swine Diets, John E. Gilley, Daniel P. Spare, Richard K. Koelsch, Dennis D. Schulte, Phillip S. Miller, Anne M. Parkhurst Aug 2000

Phototrophic Anaerobic Lagoons As Affected By Copper And Zinc In Swine Diets, John E. Gilley, Daniel P. Spare, Richard K. Koelsch, Dennis D. Schulte, Phillip S. Miller, Anne M. Parkhurst

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Odor emissions from anaerobic lagoons containing large populations of phototrophic bacteria are usually minimal. This study was conducted to determine whether copper (123 ppm) and zinc (2,310 ppm) in diets fed to weanling pigs for therapeutic purposes affect phototrophic conditions within lagoons. Column reactors containing 47 L of swine lagoon sludge and supernatant were used to represent lagoons. The reactors were placed in an environmental chamber maintained at 24° C. Copper, zinc, and control manure were added to the reactors at a volatile solids loading rate of 128 gvs m–3 da–1 using a hydraulic retention time of …

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Narrow Grass Hedge Effects On Phosphorus And Nitrogen In Runoff Following Manure And Fertilizer Application, B. Eghball, John E. Gilley, L. A. Kramer, T. B. Moorman Jan 2000

Narrow Grass Hedge Effects On Phosphorus And Nitrogen In Runoff Following Manure And Fertilizer Application, B. Eghball, John E. Gilley, L. A. Kramer, T. B. Moorman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Runoff losses of nitrogen (N) and phosphorus (P) from field applied manure can contribute to surface water pollution. Grass hedges may reduce runoff losses of nutrients and sediment. The objective of this study was to evaluate the effects of narrow switchgrass (,i>Panicum virgatum L.) hedges (~0.75 m wide) on the transport of P and N from a field receiving beef cattle feedlot manure under tilled and n-till conditions. This study was conducted on a steep (12% average slope) Monona silt loam (fine-silty, mixed, superactive, mesic Typic Hapludolls) soil near Treynor, Iowa. The experiment was a split-plot with no-till and …

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Laboratory And Field Testing Of Seed Spacing Uniformity For Sugarbeet Planters, Jonathan W. Panning, Michael F. Kocher, John A. Smith, Stephen D. Kachman Jan 2000

Laboratory And Field Testing Of Seed Spacing Uniformity For Sugarbeet Planters, Jonathan W. Panning, Michael F. Kocher, John A. Smith, Stephen D. Kachman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Five planter configurations were evaluated for seed spacing uniformity at three field speeds using a seed location method in the field and a laboratory method involving an opto-electronic sensor system. Planter seed spacing uniformity was described using the Coefficient of Precision (CP3) measure. Results showed that CP3 measures determined using the laboratory test method were significantly different from those determined using the field test method. This indicated the laboratory test method cannot be used to predict planter seed spacing uniformity in the field. Seed spacing uniformity determined in laboratory tests was higher than, or equal to, seed spacing uniformity determined …

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Performance Tests Of Three-Point Mounted Implement Guidance Systems: Ii. Results, Michael F. Kocher, Michael B. Smith, Robert D. Grisso, Linda J. Young Jan 2000

Performance Tests Of Three-Point Mounted Implement Guidance Systems: Ii. Results, Michael F. Kocher, Michael B. Smith, Robert D. Grisso, Linda J. Young

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Side-shift and disk-steer implement guidance systems were tested for differences in performance during cultivation on fields with 0 and 5% side slope. Test speeds were slow (4.8 km/h, 3 mph) and medium (8.0 km/h, 5 mph). Test path shapes included a tractor ramp, implement ramp, sine and curve. Performance measures included tractor positional error, implement positional error, torque from side forces on the cultivator non-swiveling coulters, and travel speed. Relatively few significant differences between guidance systems were detected, and most of those involved interaction with path shape. Therefore, no clear conclusion could be reached indicating one guidance system was better …

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Water Vapor Transport Parameters Of A Cast Wheat Gluten Film, Soumya Roy, Aristippos Gennadios, Curtis Weller, Robert F. Testin Jan 2000

Water Vapor Transport Parameters Of A Cast Wheat Gluten Film, Soumya Roy, Aristippos Gennadios, Curtis Weller, Robert F. Testin

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Understanding the mode of transport of water vapor through the film is important for improving the moisture barrier properties of wheat gluten (WG) films. Effective permeability (Peff), solubility (Seff), and diffusion (Deff) coefficients of a hydrophilic cast WG film were determined at 25°C within the relative humidity (RH) range of 0–84% (with a 9–13% RH gradient between upstream and downstream water vapor flux). Peff, Seff, and Deff increased substantially as the RH gradient moved upwards in the RH spectrum. Peff increased by four orders of …

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Waste Assessment Of Agricultural Chemicals, Petroleum Products And Maintenance Residuals On Farmsteads, Sherman D. Reed, Robert D. Grisso, Wayne E. Woldt, Shirley M. Niemeyer Jan 2000

Waste Assessment Of Agricultural Chemicals, Petroleum Products And Maintenance Residuals On Farmsteads, Sherman D. Reed, Robert D. Grisso, Wayne E. Woldt, Shirley M. Niemeyer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The purpose of this study was to evaluate waste management practices of purchasing, handling, storage, and disposal of agricultural chemicals, petroleum products, and maintenance residuals. One-hundred surveys were returned by agricultural producers from three Nebraska counties selected based on unique environmental and waste management issues. Twenty-four questions concerning agricultural chemicals and 16 questions directed to petroleum products and maintenance residuals are discussed. A follow-up interview with 45 respondents was conducted “on-site” to gain insight into their reported practices, perceptions, and actual practices. Most farmers (66%) tended to purchase pesticides in 3.8 to 10 L (1-2.5 gal) containers and most (79%) …

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Narrow Grass Hedge Effects On Runoff And Soil Loss, John E. Gilley, B. Eghball, L. A. Kramer, T. B. Moorman Jan 2000

Narrow Grass Hedge Effects On Runoff And Soil Loss, John E. Gilley, B. Eghball, L. A. Kramer, T. B. Moorman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This rainfall simulation study provided information on the effects of 0.72 m (2.4 ft) wide switchgrass hedges located at the bottom of plots on runoff an soil loss under both no-till and tilled conditions. The study area, which had slopes ranging from 8 to 16%, had produced corn for 33 years and the grass hedges had been established for 6 years. Simulated rainfall [64 mm hr-1)] was applied for two hours to plots [3.7 m (12 ft) wide by 10.7 m (35.1 ft) long] with corn residue and to plots where corn residue was removed. The narrow grass …

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Fractional Composition Of Grain Sorghum (Sorghum Bicolor) After Wet-Peeling In A Centrifugal Pump, K. R. Lochte-Watson, Curtis L. Weller, Kent M. Eskridge Jan 2000

Fractional Composition Of Grain Sorghum (Sorghum Bicolor) After Wet-Peeling In A Centrifugal Pump, K. R. Lochte-Watson, Curtis L. Weller, Kent M. Eskridge

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Use of a centrifugal pump to peel and facilitate separation of grain sorghum kernels into three fractions was investigated. Special emphasis was given to separating fractions to achieve a high concentration of wax in one fraction and a high concentration of starch in another. Trials were conducted to determine the effects of both soak time and recirculation time on wet-peeling. After peeling, three fractions, peeled kernel, bran, and suspended solids, were collected. Together, the bran and suspended solids fractions contained 12.7% of the initial total dry solids, 90% of initial wax, and 8.1% of the initial starch. Peeled kernel fraction …

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Performance Tests Of Three-Point Mounted Implement Guidance Systems: I. Procedure, Michael F. Kocher, Michael B. Smith, Robert D. Grisso, Leonard L. Bashford Jan 2000

Performance Tests Of Three-Point Mounted Implement Guidance Systems: I. Procedure, Michael F. Kocher, Michael B. Smith, Robert D. Grisso, Leonard L. Bashford

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A procedure is presented for determining the performance of three-point mounted implement guidance systems. A test track with tractor ramp, implement ramp, sine wave, and curve path shapes was used as the desired path to guide the tractor and implement, and as a reference location for measuring implement positional errors. Potentiometers were used with mechanical frames to measure the tractor and implement positional errors (lateral displacement between the intended and actual travel paths). An optoelectronic sensor triggered acquisition of data from all sensors at known locations [15.2 cm (6 in.) intervals] along the track. The accumulated errors for the tractor …

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Wide Tires, Narrow Tires, Leonard L. Bashford, Michael F. Kocher, Todd S. Tibbetts Sep 1999

Wide Tires, Narrow Tires, Leonard L. Bashford, Michael F. Kocher, Todd S. Tibbetts

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Tractive performance comparisons among five different size tires were made on two different surface conditions, a wheat stubble field and a tilled wheat stubble field. Radial 18.4R46, 20.8R42 and 710/70R38 radial tires; and bias 750/65-38 and 850/55-42 tires were used. Instrumentation to evaluate tractive performance was installed on a two-wheel drive and a mechanical front wheel drive agricultural tractor. Axle torques, drawbar pull, travel speed, and engine rpm were recorded for a series of drawbar pulls on the two soil surfaces. Tractive performance evaluations among the tires were made by comparing the relationships of dynamic traction ratio to slip, tractive …

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Nutrient Balance On Nebraska Livestock Confinement Systems, Richard K. Koelsch, Gary Lesoing Aug 1999

Nutrient Balance On Nebraska Livestock Confinement Systems, Richard K. Koelsch, Gary Lesoing

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Managing the environmental risk associated with livestock production is a significant challenge. Nitrogen and phosphorus are commonly implicated as the sources of ground and surface water quality problems associated with livestock production. The degree of imbalance between these nutrient inputs and the managed nutrient outputs for a livestock operation defines the magnitude of potential environmental risk and provides insight as to the underlying causes of these challenges. A nitrogen and phosphorus balance was constructed for 33 Nebraska confinement livestock operations. Twenty-five and 17 of these operations experienced significant nitrogen and phosphorus imbalances, respectively (50% more nutrient inputs than outputs). Nutrient …

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Phosphorus And Nitrogen In Runoff Following Beef Cattle Manure Of Compost Application, Bahman Eghball, John E. Gilley Jul 1999

Phosphorus And Nitrogen In Runoff Following Beef Cattle Manure Of Compost Application, Bahman Eghball, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Manure or compost from beef cattle feedlots can be an excellent sources of nutrients and organic matter when added to soils, but they can also pollute runoff. We determined the effects of simulated rainfall on runoff losses of P and N, and EC and pH following application of manure and compost to a Sharpsburg silty clay loam (fine smectitic, mesic Typic Argiudoll) soil having grain sorghum [Sorghum bicolor (L.) Moench] and winter wheat (Triticum aestivum L.) residues. Manure, compost, and fertilizer were applied to no-till fields at rates required to meet N or P requirements for corn ( …

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Z-Protected Glutamic Acid-Based Biodegradable Thermoplastic And Thermosetting Polyesters: Synthesis And Characterization, R. M. Tadros, Hossein Noureddini, Delmar C. Timm May 1999

Z-Protected Glutamic Acid-Based Biodegradable Thermoplastic And Thermosetting Polyesters: Synthesis And Characterization, R. M. Tadros, Hossein Noureddini, Delmar C. Timm

Papers in Biomaterials

Biodegradable polymers were formed from N-benzyloxycarbonyl-L-glutamic acid with the comonomers ethylene glycol, diglycidyl ether of 1,4-butanediol, and diglycidyl ether of bisphenol A. The three polymers were a linear and a cross-linked heterochain polyester and a cross-linked polyester that contained aromatic units within its network chains. The thermoplastic resin and the soluble fractions for the thermosetting resins were characterized by gel permeation chromatography. Conversions for carboxylic acid were determined by titrations. A quality, 22,000 molecular weight thermoplastic resin was formed. The two thermosets were cured past their gel points. Gelation analysis revealed that the relative rate constants for the sequential oxirane/acid …

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Liquid-Phase Catalytic Oxidation Of Unsaturated Fatty Acids , Hossein Noureddini, M Kanabur Mar 1999

Liquid-Phase Catalytic Oxidation Of Unsaturated Fatty Acids , Hossein Noureddini, M Kanabur

Papers in Biomaterials

Liquid-phase catalytic oxidation of oleic acid with hydrogen peroxide in the presence of various transition metal/metal oxide catalysts was studied in a batch autoclave reactor. Azelaic and pelargonic acids are the major reaction products. Tungsten and tantalum and their oxides in supported and unsupported forms were used as catalysts. Alumina pellets and Kieselguhr powder were used as supports for the catalysts. Tungsten, tantalum, molybdenum, zirconium, and niobium were also examined as catalysts. Tertiary butanol was used as solvent. Experimental results concluded that tungsten and tungstic oxide are more suitable catalysts in terms of their activity and selectivity. The rate of …

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Wax Yield Of Grain Sorghum (Sorghum Bicolor) As Affected By Mechanical Harvesting, Threshing, And Handling Methods, K. R. Lochte-Watson, Curtis L. Weller Jan 1999

Wax Yield Of Grain Sorghum (Sorghum Bicolor) As Affected By Mechanical Harvesting, Threshing, And Handling Methods, K. R. Lochte-Watson, Curtis L. Weller

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Wax is found on the outer layer of the grain sorghum (Sorghum bicolor) kernel. Current harvesting and handling techniques cause abrasion and breakage, thereby potentially reducing wax yield from sorghum kernels. The purpose of this study was to determine wax yield of sorghum after mechanical harvesting and handling and to compare wax yield of whole and broken sorghum kernels. Combine threshing and auger conveying of grain caused abrasion and breakage, which reduced the wax yield by 5%. The monitored process in this experiment included a cleaning system which reduced the amount of broken kernels and sorghum particles, increasing …

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Belts Vs Tires, Belts Vs Belts, Tires Vs Tires, Leonard L. Bashford, Michael F. Kocher Jan 1999

Belts Vs Tires, Belts Vs Belts, Tires Vs Tires, Leonard L. Bashford, Michael F. Kocher

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Tractive performance comparisons among two different width rubber belt tracks, 46 cm (18 in.) and 81 cm (32 in.) wide, and two different size rear tires, 710/70R38 and 18.4R46, were made on two different surface conditions. The belts were tested on a Caterpillar 55 tractor equipped with the Mobil-trac™ system and the tires on a John Deere 8400 mechanical front-wheel-drive (MFWD) tractor. The performance tests were completed on two surfaces, one being a non-tilled wheat stubble field and the second, the wheat stubble field tilled approximately 23 cm (9 in.) deep with a Noble blade sweep. Performance comparisons using tractive …

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Seepage Characteristics And Hydraulic Properties Of A Feedlot Runoff Storage Pond, David B. Parker, Dean E. Eisenhauer, Dennis D. Schulte, John A. Nienaber Jan 1999

Seepage Characteristics And Hydraulic Properties Of A Feedlot Runoff Storage Pond, David B. Parker, Dean E. Eisenhauer, Dennis D. Schulte, John A. Nienaber

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Water and chemical transport were investigated beneath a 22-year-old beef feedlot runoff storage pond. Soil and sludge samples were collected from 14 borings to 6.1-m depths in a cross-section across the pond. The soils consisted of silt loam and clay loam, and the groundwater level was about 30 m beneath the land surface. Soil samples were analyzed for pH, NO3-N, NH4-N, Cl, P, K, SO4-S, TKN, and organic matter. Physical and hydraulic properties were measured on undisturbed samples of soil and sludge to compare saturated hydraulic conductivity, moisture release characteristics, and bulk density. Saturated …

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The Certified Safe Farm Project In Nebraska: The First Year, Jerry Jaspersen, Susanna Von Essen, Pam List, Larry Howard, David Morgan Jan 1999

The Certified Safe Farm Project In Nebraska: The First Year, Jerry Jaspersen, Susanna Von Essen, Pam List, Larry Howard, David Morgan

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Potentially preventable death, disabling injury, and serious illness are very common secondary to work in production agriculture in Nebraska and elsewhere. The traditional approach to farm safety has consisted largely of education designed to prevent traumatic injury. While education is of critical importance, additional incentives may be needed to reduce fatal and non-fatal events to an acceptable level. The Certified Safe Farm concept was developed in collaboration with two Nebraska health insurance companies. The program consists of combining an on-farm safety assessment and occupational health screening with an education program. The incentive to complete this program is to be eligible …

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Nitrate Leaching In Irrigated Corn And Soybean In A Semi-Arid Climate, N. L. Klocke, Darrell G. Watts, J. P. Schneekloth, Don R. Davison, R. W. Todd, Anne M. Parkhurst Jan 1999

Nitrate Leaching In Irrigated Corn And Soybean In A Semi-Arid Climate, N. L. Klocke, Darrell G. Watts, J. P. Schneekloth, Don R. Davison, R. W. Todd, Anne M. Parkhurst

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Nitrate-nitrogen leached from the root zone of land in intensive corn production is a major groundwater contaminant in some of the intensively irrigated regions of the western Cornbelt, including central and western Nebraska. To obtain a clearer understanding of the amount and timing of nitrate leaching losses from irrigated crops, 14 monolithic percolation lysimeters were installed in 1989-1990 in sprinkler irrigated plots at the University of Nebraska’s West Central Research and Extension Center near North Platte, Nebraska. The lysimeters were used to provide a direct measure of leachate depth from continuous corn and a corn-soybean rotation. Both cropping systems were …

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Opto-Electronic Sensor System For Laboratory Measurement Of Planter Seed Spacing With Small Seeds, Y. Lan, Michael F. Kocher, John A. Smith Jan 1999

Opto-Electronic Sensor System For Laboratory Measurement Of Planter Seed Spacing With Small Seeds, Y. Lan, Michael F. Kocher, John A. Smith

Department of Agricultural and Biological Systems Engineering: Faculty Publications

An opto-electronic sensor system for measuring seed spacing uniformity with different types of seeds is described in this paper. It consisted of a rectangular photogate block (124 × 92 mm) with 24 phototransistors (diameter, 3 mm) receiving light beams from 24 light emitting diodes (diameter, 3 mm) opposite them, a digital input/output board in a personal computer, and power supplies. The opto-electronic system was tested by comparing seed spacing measurements obtained from the opto-electronic system with measurements of the same seed spacings obtained from a grease belt test stand. The tests were conducted with different types of seeds including regular-pelleted …

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A Continuous Process For The Conversion Of Vegetable Oils Into Methyl Esters Of Fatty Acids, Hossein Noureddini, D Harkey, V Medikonduru Dec 1998

A Continuous Process For The Conversion Of Vegetable Oils Into Methyl Esters Of Fatty Acids, Hossein Noureddini, D Harkey, V Medikonduru

Papers in Biomaterials

A continuous process for the transesterification of triglycerides to methyl esters was investigated in a pilot plant. The process was equipped with a motionless and a high-shear mixer. The experimental studies explored variations in the mixing intensity, stoichiometry, and catalyst concentration on the overall conversion. The combined as well as individual effect of mixers was examined. The developed process resulted in high conversions of vegetable oils into methyl esters. Conversion of triglycerides to methyl esters in excess of 98% was achieved. Larger excess amounts of alcohol favored higher conversions. The motionless and high-shear mixers each provided adequate mixing for the …

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Enzymatic Glycerolysis Of Soybean Oil , Hossein Noureddini, S E. Harmeier Oct 1998

Enzymatic Glycerolysis Of Soybean Oil , Hossein Noureddini, S E. Harmeier

Papers in Biomaterials

Enzymatic glycerolysis of soybean oil was studied. Of the nine lipases that were tested in the initial screening, Pseudomonas sp. resulted in the highest yield of monoglycerides. Lipase from Pseudomonas sp. was further studied for the influence of temperature, thermal stability, enzyme/oil ratio, and glycerol/oil ratio. A full factorial optimization approach was performed. The following conditions were tested over the specified ranges: temperature (30?70°C), thermal stability (30?70°C), enzyme/oil ratio (0.05?0.2 g enzyme/10 g oil), glycerol/oil ratio (1:1?3:1 glycerol/oil molar ratio) and 1 h reaction time. The stability of the enzyme at the reaction temperature was also incorporated as a separate …

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