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Articles 1471 - 1500 of 2277
Full-Text Articles in Civil and Environmental Engineering
P96. Three-Dimensional Morphometry Of Human Cervical Endplates, Rebecca A. Wachs, Victoria M. Michna, Eric H. Ledet
P96. Three-Dimensional Morphometry Of Human Cervical Endplates, Rebecca A. Wachs, Victoria M. Michna, Eric H. Ledet
Department of Agricultural and Biological Systems Engineering: Faculty Publications
BACKGROUND CONTEXT: Degeneration of the cervical intervertebral disc is the underlying cause for many patients suffering from neck and upper extremity pain. Anterior cervical discectomy and fusion, and cervical disc replacements are common, but next generation implants and less invasive surgical techniques are predicated on a comprehensive characterization of cervical endplate morphology. To date, cervical endplate morphometry has not been described in detail, and age-related and gender- dependent differences have not been characterized.
PURPOSE: The purposes of this research were to measure cervical endplate morphometry in both men and women across three decades of life and characterize age, gender, and …
Field Performance Evaluation Of A Ventilation System: A Swine Case Study, Jay D. Harmon, Michael C. Brumm, Larry D. Jacobson, Stephen H. Pohl, David R. Stender, Richard R. Stowell
Field Performance Evaluation Of A Ventilation System: A Swine Case Study, Jay D. Harmon, Michael C. Brumm, Larry D. Jacobson, Stephen H. Pohl, David R. Stender, Richard R. Stowell
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Swine finishing facility ventilation has become relatively complex and is often mismanaged as a system. One of the few ways to truly understand these systems is to spend time systematically going through the many components of the building and how they work as a system. To learn to help producers better, a team of university Extension specialists that included agricultural engineers and animal scientists spent an extended period carefully documenting conditions in a deep‐pit swine finishing building with two 1,000‐head rooms. Exhaust fans connected to the manure pit and wall fans were operated at various stages as a negative‐pressure ventilation …
Trapping Phosphorus In Runoff With A Phosphorus Removal Structure, Chad J. Penn, Joshua M. Mcgrath, Elliott Rounds, Garey A. Fox, Derek M. Heeren
Trapping Phosphorus In Runoff With A Phosphorus Removal Structure, Chad J. Penn, Joshua M. Mcgrath, Elliott Rounds, Garey A. Fox, Derek M. Heeren
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Reduction of phosphorus (P) inputs to surface waters may decrease eutrophication. Some researchers have proposed fi ltering dissolved P in runoff with P-sorptive byproducts in structures placed in hydrologically active areas with high soil P concentrations. Th e objectives of this study were to construct and monitor a P removal structure in a suburban watershed and test the ability of empirically developed fl ow-through equations to predict structure performance. Steel slag was used as the P sorption material in the P removal structure. Water samples were collected before and after the structure using automatic samples and analyzed for total dissolved …
Calibration Of Microsimulation Models For Multimodal Freight Networks, Justice Appiah Ph.D., P.E., Bhaven Naik, Scott Sorensen
Calibration Of Microsimulation Models For Multimodal Freight Networks, Justice Appiah Ph.D., P.E., Bhaven Naik, Scott Sorensen
Mid-America Transportation Center: Final Reports and Technical Briefs
This research presents a framework for incorporating the unique operating characteristics of multi-modal freight networks into the calibration process for microscopic traffic simulation models. Because of the nature of heavy freight movements in US DOT Region VII (Nebraska, Iowa, Missouri, Kansas), the focus of the project is on trucks or heavy gross vehicles (HGV). In particular, a genetic algorithm (GA) based optimization technique was developed and used to find optimum parameter values for the vehicle performance model used by “Verkehr In Staedten-SIMulationmodell (VISSIM)”, a widely used microscopic traffic simulation software. At present, the Highway Capacity Manual (HCM), which is the …
Phase I Development Of An Aesthetic, Precast Concrete Bridge Rail, Ronald K. Faller, Scott K. Rosenbaugh, Robert W. Bielenberg, Dean L. Sicking, John D. Reid
Phase I Development Of An Aesthetic, Precast Concrete Bridge Rail, Ronald K. Faller, Scott K. Rosenbaugh, Robert W. Bielenberg, Dean L. Sicking, John D. Reid
Mid-America Transportation Center: Final Reports and Technical Briefs
Precast concrete bridge rail systems offer several advantages over traditional cast-in-place rail designs, including reduced construction time and costs, installation in a wide range of environmental conditions, easier maintenance and repair, improved railing quality, and greater flexibility for aesthetic treatments. The objective of this project was to develop a precast concrete bridge rail system that met the TL-4 impact safety standards provided in MASH. The design criteria for the new bridge rail system included criteria for barrier geometry, provisions for open and closed rail options, constructability, weight limitations, segment length, design impact loads, connection of barrier segments, and connection to …
Truck Safety At Highway-Rail Grade Crossings, Aemal Khattak, Miao Gao
Truck Safety At Highway-Rail Grade Crossings, Aemal Khattak, Miao Gao
Mid-America Transportation Center: Final Reports and Technical Briefs
Safety at highway-rail grade crossings (HRGC) is a major concern for different agencies because increasing highway and rail traffic presents a greater risk of crashes at these locations. In 2008, there were 2,391 crashes and 523 fatalities reported at grade crossings across the U.S. Of these, 187 crashes were reported in Nebraska, including 35 involving trucks with trailers and 10 involving trucks only. At gated crossings, gate-related violations by truck drivers are a primary cause of collisions between trains and trucks. The objectives of this research were to report on the frequency and type of gate violations by truck drivers …
Assessing The Risk Of Crash For Trucks On Onset Yellow, Anuj Sharma Ph.D., Nathaniel P. Burnett
Assessing The Risk Of Crash For Trucks On Onset Yellow, Anuj Sharma Ph.D., Nathaniel P. Burnett
Mid-America Transportation Center: Final Reports and Technical Briefs
Each day, millions of signal changes to the yellow phase occur at isolated high speed intersections, when erroneous driver decisions to stop or go may often lead to a crash. Dilemma zone protection systems are typically used to control these intersections in order to ensure the safe and efficient movement of vehicles. However, traditional dilemma zone protection systems show deterioration in performance during medium to heavy traffic volume conditions, jeopardizing both the safety and efficiency of intersections. The performance of these control systems for heavy vehicles is even more greatly affected, as traditional dilemma zone boundaries were developed for passenger …
Effect Of Freeway Level Of Service And Driver Education On Truck Driver Stress - Phase 1, Anuj Sharma Ph.D., Senem Velipasalar Ph.D., Sanjay Singh M.D., Dave Engel B.S., Sunil Gyawali Ph.D.
Effect Of Freeway Level Of Service And Driver Education On Truck Driver Stress - Phase 1, Anuj Sharma Ph.D., Senem Velipasalar Ph.D., Sanjay Singh M.D., Dave Engel B.S., Sunil Gyawali Ph.D.
Mid-America Transportation Center: Final Reports and Technical Briefs
This research primarily deals with truck driver stress and its nature, stressors, and their mutual relationship. During the study, the different demands of driving that are related to roads, vehicle, traffic conditions, driver predisposition to stress and the surrounding environmental conditions were explored. The two distinct clusters of ―Low Stress level‖ and ―High Stress level‖ were identified in the stress distribution. The binary logistic regression method was used to relate these two conditions of stress with wide range of stressors. The result found that truck driver training was a statistically significant factor in predicting the low stress level. Other statistically …
Intellidrive Technology Based Yellow Onset Decision Assistance System For Trucks, Anuj Sharma Ph.D., Nathaniel Burnett, Sepideh S. Aria Ph.D.
Intellidrive Technology Based Yellow Onset Decision Assistance System For Trucks, Anuj Sharma Ph.D., Nathaniel Burnett, Sepideh S. Aria Ph.D.
Mid-America Transportation Center: Final Reports and Technical Briefs
Erroneous decisions by drivers to stop or go at the onset of yellow can lead to incidences of premature stopping or red light running, which in turn can cause severe rear end or right angle collisions. Because trucks or busses are relatively less maneuverable, have lower available acceleration and lower comfortable deceleration rates, and have a higher line of sight than do passenger vehicles, the risk of crashes is higher for trucks than other vehicles upon stop or go situations. Dilemma zone protection systems are used at high speed intersection s to enhance safety; however, such systems are generally designed …
Cable Median Barrier Failure Analysis And Prevention, Dean L. Sicking, Cody S. Stolle
Cable Median Barrier Failure Analysis And Prevention, Dean L. Sicking, Cody S. Stolle
Mid-America Transportation Center: Final Reports and Technical Briefs
Cross-median crashes have been identified as one of the highest injury or fatality risk crash types. Although crossmedian crashes account for only 2% to 5% of all median crash events, they are disproportionately represented in the number and frequency of fatalities on interstate roadways. Many states have utilized cable median barriers to reduce the risk of cross-median crashes, frequently with great success. However, cable median barriers are also fixed obstacles to errant vehicles. Cable median barriers can place occupants at increased risk of severe injury or fatality if the barrier fails to adequately contain and redirect errant vehicles, resulting in …
Feasibility Of Integrating Natural And Constructed Wetlands In Roadway Drainage System Design, John S. Stansbury, Massom Moussavi, Tian Zhang
Feasibility Of Integrating Natural And Constructed Wetlands In Roadway Drainage System Design, John S. Stansbury, Massom Moussavi, Tian Zhang
Mid-America Transportation Center: Final Reports and Technical Briefs
Stormwater from roadways could have negative effects on the environment and aquatic ecosystems. Typical highway runoff pollutants include solids; heavy metals, particularly cadmium, copper, and zinc; petroleum hydrocarbons; gasoline constituents; PAHs (polyaromatic hydrocarbons); oxygen demanding compounds measured as COD (chemical oxygen demand) and BOD (biochemical oxygen demand); and road salts. Roadway runoff falls under the legislation of the Clean Water Act (CWA) via the National Pollutant Discharge Elimination System (NPDES). CWA regulates discharge of nonpoint source pollutants, such as roadway runoff, by issuing permits to public entities which manage Municipal Separate Storm Sewer Systems (MS4s). Part of the Nebraska Department …
Characteristics And Contributory Causes Related To Large Truck Crashes - Phase Ii, Sundanda Dissanayake Ph.D., P.E., Siddhartha Kotikalapudi
Characteristics And Contributory Causes Related To Large Truck Crashes - Phase Ii, Sundanda Dissanayake Ph.D., P.E., Siddhartha Kotikalapudi
Mid-America Transportation Center: Final Reports and Technical Briefs
Statistics clearly demonstrate that large-truck crashes contribute to a significant percentage of high-severity crashes. It is therefore important for the highway safety community to identify the characteristics and contributory causes of these types of crashes. The first phase of the current research endeavor examined fatal crash data from the Fatality Analysis Reporting System (FARS) database. In the second phase, presented in the current report, truck-crashes of all severity levels were analyzed with the intention of understanding characteristics and contributory causes, as well as identifying factors contributing to increased severity of truck-crashes. This goal could not be achieved by analyzing fatal …
Improving Safety Of The Surface Transportation System By Addressing The Issues Of Vulnerable Road Users: Case Of The Motorcyclists, Sundanda Dissanayake Ph.D., P.E., Mohammad Saad B. Shaheed
Improving Safety Of The Surface Transportation System By Addressing The Issues Of Vulnerable Road Users: Case Of The Motorcyclists, Sundanda Dissanayake Ph.D., P.E., Mohammad Saad B. Shaheed
Mid-America Transportation Center: Final Reports and Technical Briefs
Over the past few years, motorcycle fatalities have increased at an alarming rate in the United States. Motorcycle safety issues in Kansas are no different from the national scenario. Accordingly, this study examines motorcycle crashes in Kansas in order to identify and evaluate critical crash-related factors and subsequent impacts on motorcycle crash injury outcomes. State-level motorcycle rider fatality rates were investigated while considering various factors including helmet laws, using generalized least-squares regression modeling. A detailed characteristic analysis was carried out for motorcycle crashes, using Kansas crash data. Comparisons were made between several aspects of motorcycle crashes and other vehicle crashes. …
Evaluation Of Large Truck Crashes At Horizontal Curves On Two-Lane Rural Highways In Kansas, Eric J. Fitzsimmons Ph.D., Steven Shruck Ph.D., P.E., Tomas E. Lindheimer
Evaluation Of Large Truck Crashes At Horizontal Curves On Two-Lane Rural Highways In Kansas, Eric J. Fitzsimmons Ph.D., Steven Shruck Ph.D., P.E., Tomas E. Lindheimer
Mid-America Transportation Center: Final Reports and Technical Briefs
The objective of this study was to investigate the relationship between roadway and environment-related factors and truck crash severity at horizontal curves located on rural, two-lane state highways in Kansas. Single vehicle truck crashes and multi-vehicle crashes involving at least one truck were extracted from the Kansas Department of Transportation’s crash and roadway databases for the years 2006-2010, resulting in 452 crash records. Descriptive statistics and 95 percent confidence intervals were constructed for an odds ratio analysis comparing single-vehicle truck crashes to multi-vehicle crashes involving at least one truck for the variables that were included in both databases. Overall, the …
A Preliminary Appraisal Of The Safety And Operational Effects On The Regional Transportation System Caused By New Rail- Truck Intermodal Facilities, Thomas E. Mullinazzi, Steven D. Schrock, Eric J. Fitzsimmons, Robert A. Rescot
A Preliminary Appraisal Of The Safety And Operational Effects On The Regional Transportation System Caused By New Rail- Truck Intermodal Facilities, Thomas E. Mullinazzi, Steven D. Schrock, Eric J. Fitzsimmons, Robert A. Rescot
Mid-America Transportation Center: Final Reports and Technical Briefs
Potential for impacts to a small Kansas city were evaluated in light of a planned rail to truck intermodal facility. The city of Edgerton, Kansas, was selected for an intermodal terminal in 2006 by a Class I railroad due to its regional proximity to the Kansas City market and market conditions favorable to such a facility. Through an analysis of various reports and literature along with original traffic, railroad, and environmental data, along with citizen feedback, the framework was laid to be able to compare the impacts of the facility to a snapshot in time prior to its opening.
Earmarked Revenues And Spending Volatility: The Case Of Highway Finance, Phuong Nguyen-Hoang Ph.D., William Duncombe Ph.D.
Earmarked Revenues And Spending Volatility: The Case Of Highway Finance, Phuong Nguyen-Hoang Ph.D., William Duncombe Ph.D.
Mid-America Transportation Center: Final Reports and Technical Briefs
Over the last decade, state governments have experienced two recessions (including the recent “Great Recession”) which have resulted in significant disruptions in state budgets and highlighted the volatility of the personal income tax and general sales tax. Since infrastructure maintenance funding may be particularly vulnerable to budget cuts during recessions, it is important to identify more stable revenue sources and budgetary institutions. One of the distinguishing characteristics of highway finance in the United States is the heavy use of earmarked revenues linked to highway users. Our key research question is whether an increase in the share of highway funding from …
Determining The Stresses In Steel Railroad-Track Rails Due To Freight Movements Using Non-Contact Laser-Speckle, Robert Peterman Ph.D., P.E., Rob Murphy, Weixin Zhao Ph.D.
Determining The Stresses In Steel Railroad-Track Rails Due To Freight Movements Using Non-Contact Laser-Speckle, Robert Peterman Ph.D., P.E., Rob Murphy, Weixin Zhao Ph.D.
Mid-America Transportation Center: Final Reports and Technical Briefs
This research was aimed at developing a procedure to determine the existing stresses in steel rails used in railroad tracks. These stresses are caused by the combination of both thermal restraint and physical/mechanical loads. However, since the track sections are installed at various temperatures and then continuously welded together and secured to wood or concrete ties, the stresses existing in the track at any given time are currently unknown. In fact, not only the magnitude of stress is unknown, but also the basic knowledge about whether the rails are in tension or compression at a given time. Since the stresses …
2012 Nebraska Water Monitoring Programs Report, Marty Link, Mike Archer
2012 Nebraska Water Monitoring Programs Report, Marty Link, Mike Archer
Nebraska Department of Environmental Quality: Reports
The following Nebraska Department of Environmental Quality staff have contributed to this report with their photos, maps, numbers, words, and editing. Their efforts are greatly appreciated and gratefully acknowledged here: Mike Archer, Ken Bazata, Dave Bubb, Ryan Chapman, Jason Garber, Patrick Hartman, Tom Heatherly, Dave Ihrie, Dan Inman, Greg Michl, Will Myers, Patrick O’Brien (NARD), Brad Routt, and Dave Schumacher.
Optimal Advance Detector Location For Green Termination Systems On High-Speed Isolated Rural Intersections, Lili Du, Anuj Sharma, Srinivas Peeta
Optimal Advance Detector Location For Green Termination Systems On High-Speed Isolated Rural Intersections, Lili Du, Anuj Sharma, Srinivas Peeta
Department of Civil and Environmental Engineering: Faculty Publications
This study seeks to identify the optimal location of an advance point traffic detector (APTD) to support green termination algorithms for enhanced dilemma zone protection systems at high-speed isolated signalized rural intersections. This is done by developing a nonlinear optimization model with the objective to maximize the opportunities to predict empty dilemma zones during a look-ahead time period subject to the prediction accuracy which is manifested through prediction efficiency and safety constraints in the model. The distance of the APTD from the stop bar of the intersection represents the decision variable. The Golden-Section line search algorithm combined with numerical integration …
Methane And Carbon Dioxide Production From Simulated Anaerobic Degradation Of Cattle Carcasses, Qi Yuan, Samuel Saunders, Shannon L. Bartelt-Hunt
Methane And Carbon Dioxide Production From Simulated Anaerobic Degradation Of Cattle Carcasses, Qi Yuan, Samuel Saunders, Shannon L. Bartelt-Hunt
Department of Civil and Environmental Engineering: Faculty Publications
Approximately 2.2 million cattle carcasses require disposal annually in the United States. Land burial is a convenient disposal method that has been widely used in animal production for disposal of both daily mortalities as well as during catastrophic mortality events. To date, greenhouse gas production after mortality burial has not been quantified, and this study represents the first attempt to quantify greenhouse gas emissions from land burial of animal carcasses. In this study, anaerobic decomposition of both homogenized and unhomogenized cattle carcass material was investigated using bench-scale reactors. Maximum yields of methane and carbon dioxide were 0.33 and 0.09 m …
Fabrication And Characterization Of Dna-Loaded Zein Nanospheres, Mary C. Regier, Jessica D. Taylor, Tyler Borcyk, Yiqi Yang, Angela K. Pannier
Fabrication And Characterization Of Dna-Loaded Zein Nanospheres, Mary C. Regier, Jessica D. Taylor, Tyler Borcyk, Yiqi Yang, Angela K. Pannier
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Background: Particulates incorporating DNA are promising vehicles for gene delivery, with the ability to protect DNA and provide for controlled, localized, and sustained release and transfection. Zein, a hydrophobic protein from corn, is biocompatible and has properties that make it a promising candidate material for particulate delivery, including its ability to form nanospheres through coacervation and its insolubility under physiological conditions, making it capable of sustained release of encapsulated compounds. Due to the promise of this natural biomaterial for drug delivery, the objective of this study was to formulate zein nanospheres encapsulating DNA as the therapeutic compound, and to …
Quantification And Heterogeneity Of Infiltration And Transport In Alluvial Floodplains, Derek M. Heeren, Garey A. Fox, Daniel E. Storm, Peter Q. Storm, Brian E. Haggard, Todd Halihan, Ronald B. Miller
Quantification And Heterogeneity Of Infiltration And Transport In Alluvial Floodplains, Derek M. Heeren, Garey A. Fox, Daniel E. Storm, Peter Q. Storm, Brian E. Haggard, Todd Halihan, Ronald B. Miller
Department of Agricultural and Biological Systems Engineering: Faculty Publications
In order to protect drinking water systems and aquatic ecosystems, all critical nutrient source areas and transport mechanisms need to be characterized. It is hypothesized that hydrologic heterogeneities (e.g., macropores and gravel outcrops) in the subsurface of floodplains play an integral role in impacting flow and contaminant transport between the soil surface and shallow alluvial aquifers which are intricately connected to streams. Infiltration is often assumed to be uniform at the field scale, but this neglects the high spatial variability common in anisotropic, heterogeneous alluvial floodplain soils. In the Ozark ecoregion, for example, the erosion of carbonate bedrock (primarily limestone) …
Berm Method For Quantification Of Infiltration And Leaching At The Plot Scale In High Conductivity Soils, Derek M. Heeren, Garey A. Fox, Daniel E. Storm
Berm Method For Quantification Of Infiltration And Leaching At The Plot Scale In High Conductivity Soils, Derek M. Heeren, Garey A. Fox, Daniel E. Storm
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Measuring infiltration and leaching at the plot scale is difficult, especially for high hydraulic conductivity soils. Infiltration rate has been indirectly calculated at the plot scale by comparing surface runoff to rainfall. Direct measurement of infiltration and leaching beyond the point scale is typically limited to locations where land forming has been performed, e.g. infiltration ponds and fields with basin irrigation. The standard method for field measurement of infiltration is a double ring infiltrometer, which is limited in size (typically 30 cm diameter). In this research, a new method is proposed that uses a temporary berm constructed of a water …
Field Scale Modeling To Estimate Phosphorus And Sediment Load Reductions Using A Newly Developed Graphical User Interface For Soil And Water Assessment Tool, Aaron R. Mittelstet, Erin R. Daly, Daniel E. Storm, Michael J. White, Greg A. Kloxin
Field Scale Modeling To Estimate Phosphorus And Sediment Load Reductions Using A Newly Developed Graphical User Interface For Soil And Water Assessment Tool, Aaron R. Mittelstet, Erin R. Daly, Daniel E. Storm, Michael J. White, Greg A. Kloxin
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Streams throughout the North Canadian River watershed in northwest Oklahoma, USA have elevated levels of nutrients and sediment. Soil and Water Assessment Tool (SWAT) was used to identify areas that likely contributed disproportionate amounts of Phosphorus (P) and sediment to Lake Overholser, the receiving reservoir at the watershed outlet. These sites were then targeted by the Oklahoma Conservation Commission (OCC) to implement conservation practices, such as conservation tillage and pasture planting as part of a US Environmental Protection Agency Section 319(h) project. Conservation practices were implemented on 238 fields. The objective of this project was to evaluate conservation practice effectiveness …
Whose Water Is It Anyway? Comparing The Water Rights Frameworks Of Arkansas, Oklahoma, Texas, New Mexico, Georgia, Alabama, And Florida, M. D. Smolen, Aaron R. Mittelstet, Bekki Harjo
Whose Water Is It Anyway? Comparing The Water Rights Frameworks Of Arkansas, Oklahoma, Texas, New Mexico, Georgia, Alabama, And Florida, M. D. Smolen, Aaron R. Mittelstet, Bekki Harjo
Department of Agricultural and Biological Systems Engineering: Faculty Publications
In most states surface waters, (streams, lakes, and coastal waters) are owned by the public. On the other hand, ground water may be privately or publicly owned. Because all waters are linked through the hydrologic cycle, and the hydrologic cycle is not confined within any geographic or political boundary, the question of ownership is generally replaced by one of who has the right to manage, divert, use, or sell the water.
Comparison Of 2-Way Versus Metered 3-Way Boom Shut-Off Valves For Automatic Section Control On Agricultural Sprayers, Ajay Sharda, Joe D. Luck, John P. Fulton, Timothy P. Mcdonald, Scott A. Shearer, Daniel K. Mullenix
Comparison Of 2-Way Versus Metered 3-Way Boom Shut-Off Valves For Automatic Section Control On Agricultural Sprayers, Ajay Sharda, Joe D. Luck, John P. Fulton, Timothy P. Mcdonald, Scott A. Shearer, Daniel K. Mullenix
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Modern spray rate controllers along with technologies such as automatic section control (ASC) provide benefits such as overlap reduction on agricultural sprayers. However, product (liquid) dynamics within the boom plumbing affect off-rate errors and application uniformity during rate changes and ASC actuation. Therefore, this study was conducted to compare nozzle flow stability and uniformity across the boom when using two different boom shut-off valves (2-way and metered 3-way) on an 18.3-m sprayer boom. Pressure transducers were mounted at 1) the boom manifold, 2) randomly at 12 nozzle bodies across the spray boom, and 3) upstream and downstream of the flow …
Selecting Sprinkler Packages For Center Pivots, Derrel L. Martin, William L. Kranz, Allen L. Thompson, Hong Liang
Selecting Sprinkler Packages For Center Pivots, Derrel L. Martin, William L. Kranz, Allen L. Thompson, Hong Liang
Department of Agricultural and Biological Systems Engineering: Faculty Publications
Center pivots are the primary method of irrigation across the U.S. Great Plains. Center-pivot irrigation is also the fastest growing method of irrigation in the U.S. and around the world. Pivots have the potential to be very efficient and uniform if sprinkler devices are properly selected for local field conditions. New water application devices provide for selection that minimizes runoff and controls droplet sizes to reduce evaporation and drift losses. We present updates to models for computing runoff potential based on characteristics of sprinkler devices and soil textural classes. A dimensionless solution to the Green-Ampt infiltration method for center pivots …
Sensitivity Of Grass- And Alfalfa-Reference Evapotranspiration To Weather Station Sensor Accuracy, Dana O. Porter, Prasanna H. Gowda, Thomas H. Marek, Terry A. Howell, Jerry Moorhead, Suat Irmak
Sensitivity Of Grass- And Alfalfa-Reference Evapotranspiration To Weather Station Sensor Accuracy, Dana O. Porter, Prasanna H. Gowda, Thomas H. Marek, Terry A. Howell, Jerry Moorhead, Suat Irmak
Department of Agricultural and Biological Systems Engineering: Faculty Publications
A sensitivity analysis was conducted to determine the relative effects of measurement errors in climate data input parameters on the accuracy of calculated reference crop evapotranspiration (ET) using the ASCE-EWRI Standardized Reference ET Equation. Data for the period of 1995 to 2008 from an automated weather station located at the USDA-ARS Conservation and Production Research Laboratory at Bushland, Texas were used for the analysis. Results
indicated that grass (ETos) and alfalfa (ETrs) reference crop ET were most sensitive to measurement errors in wind speed and air temperature followed by incoming shortwave (solar) radiation, and that data …
Evaluation Of A Rhodamine-Wt Dye/Glycerin Mixture As A Tracer For Testing Direct Injection Systems For Agricultural Sprayers, Joe D. Luck, Scott A. Shearer, Brian D. Luck, Fred A. Payne
Evaluation Of A Rhodamine-Wt Dye/Glycerin Mixture As A Tracer For Testing Direct Injection Systems For Agricultural Sprayers, Joe D. Luck, Scott A. Shearer, Brian D. Luck, Fred A. Payne
Department of Agricultural and Biological Systems Engineering: Faculty Publications
The purpose of this study was to provide valuable insight regarding the use of Rhodamine WT (red) dye as a tracer for evaluating injected concentrations. More specifically, the effects of mixing the dye with glycerin to simulate the viscosity of a pesticide (e.g., glyphosate) or injecting the dye/glycerin mixture into deionized (DI) versus tap water on developing appropriate calibration equations were evaluated. Test results indicated that mixing the dye in a solution of glycerin and DI water significantly affected absorbance measurements compared to the dye mixed solely in DI water. The error in estimating absorbance was 7.4% between the two …
Swat: Model Use, Calibration, And Validation, Jeffrey G. Arnold, Daniel N. Moriasi, Philip W. Gassman, Karim C. Abbaspour, Michael J. White, Raghavan Srinivasan, Chinnasamy Santhi, Daren Harmel, Ann Van Griensven, Michael W. Van Liew, Narayanan Kannan, Manoj K. Jha
Swat: Model Use, Calibration, And Validation, Jeffrey G. Arnold, Daniel N. Moriasi, Philip W. Gassman, Karim C. Abbaspour, Michael J. White, Raghavan Srinivasan, Chinnasamy Santhi, Daren Harmel, Ann Van Griensven, Michael W. Van Liew, Narayanan Kannan, Manoj K. Jha
Department of Agricultural and Biological Systems Engineering: Faculty Publications
SWAT (Soil and Water Assessment Tool) is a comprehensive, semi-distributed river basin model that requires a large number of input parameters, which complicates model parameterization and calibration. Several calibration techniques have been developed for SWAT, including manual calibration procedures and automated procedures using the shuffled complex evolution method and other common methods. In addition, SWAT-CUP was recently developed and provides a decision-making framework that incorporates a semi-automated approach (SUFI2) using both manual and automated calibration and incorporating sensitivity and uncertainty analysis. In SWAT-CUP, users can manually adjust parameters and ranges iteratively between autocalibration runs. Parameter sensitivity analysis helps focus the …