Engineering Commons^™

Narrow Grass Hedge Effects On The Transport Of Antimicrobials And Antimicrobial Resistance Genes Following Land Application Of Swine Slurry, Bhavneet Soni

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The objective of this study was to determine the effects of manure amendment and narrow grass hedges on the fate and transport of antimicrobials and ARGs in runoff and in soil following the land application of swine manure slurry. Swine manure slurry was land applied to 0.75m wide by 4.0m long plots established on an Aksarben silty clay loam soil located in southeast Nebraska. The treatment factor manure amendment consisted of two levels: no manure application and manure application to meet the 3 year nitrogen (N) requirements for corn. The treatment factor of grass hedge was established for half of …

The Effect Of Skew Angle On Average Queue Delay At Tee-Intersections: A Simulation Study Using The Texas Model, Manogna Kaluva

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

This thesis explores the effect of intersection skew angle on average queue delay through simulation. The simulation model used is the TEXAS (Traffic Experimental and Analytical Simulation) model. This microscopic simulation model uses a general nonlinear car-following model. It simulates individual intersections and was designed to capture the interaction of traffic operations and intersection geometry.

Simulation models were developed for three stop-controlled, tee-intersections in Lincoln, Nebraska. Field data to develop and calibrate the simulation models were collected. All simulation models were calibrated by adjusting the car following parameters. An experimental design was developed to test the effect of skew angle …

Development Of A Field Test For Total Suspended Solids Analysis, Jessica Branigan

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Total suspended solids (TSS) are all particles in water that will not pass through a glass fiber filter with a pore size less than 2 μm, including sediments, algae, nutrients, and metals. TSS is an important water quality parameter because of its adverse effects on aquatic species and wildlife. The EPA has proposed a regulation for turbidity, a related water quality parameter, which has been stayed pending further testing. TSS is regulated through the EPA via the NPDES in many states. Since there are no accepted field tests for TSS, projects with TSS regulations must send samples to a laboratory …

Passive Stormwater Samplers For Sampling Highway Runoff From Bmps: Feasibility Studies, Mitchell R. Klein

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Pollution from highway stormwater runoff has been an increasing area of concern within the environmental field. To respond to the need for reduced contamination within runoff many Best Management Practices (BMPs) have been implemented. One difficult aspect of BMPs is monitoring their effectiveness along with determining effluent concentrations. The current methods for stormwater sampling include sending technicians or installing an auto-sampler to collect either grab or composite samples. These methods become costly, cumbersome and infeasible due to the potentially large amount of BMPs across a region and the irregularity and difficulty of predicting storms. Passive samplers have proven themselves as …

Reliability Analysis Of Shallow Foundations Bearing Capacity On Sand, Ali Alhajami

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Bearing capacity of shallow foundation is one of the most challenging problems for engineers. The difficulty comes from multiple sources of variability and uncertainty. There is an uncertainty in live load. Soil properties including: unit weight, cohesion, and angle of friction represent sources of variability in the determining bearing capacity. The current theories used in practice only estimate bearing capacity and does not give an exact value for it because of these sources of variability. Currently, there are Terzaghi, Meyerhof, Vesic, and Hansen theories for dealing with this problem. Based on previous research Terzaghi theory was found to be the …

Driver Fatigue Enforcement Techniques And Their Effect On Crashes, Carrie Mohlman

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Fatigued driving is a type of driver impairment caused by a lack of sleep, sleep disorders, long drive times, etc. Fatigued driving enforcement aims to improve safety by removing impaired drivers from the roadway. While fatigued driving is detrimental to safety, there exists the issue of identifying fatigue. There is a range between being awake and asleep and, in order to improve safety, enforcement officers must be able to identify the point at which drivers are impaired.

This thesis investigates potentially effective fatigued driving enforcement techniques for use by enforcement officers. These techniques were investigated through three primary means: a …

Velocity Measurements Of The Flow Over A Gate-Controlled Weir Structure, Mohamed M. Jalloh

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The South Florida Water Management District (SFWMD) uses G304 control structures to manage flow into and out of a large storm-water treatment area (STA). These structures consist of a lateral unsuppressed weir, a sluice gate and a corrugated culvert for flow control and transfer through an embankment. For better flow control in the STAs, it is imperative to accurately measure the discharge through the G304 control structures and to determine the approach velocity over the weir for different field scenarios.

Flow behavior of the G304 structure was examined in a prototype during two days of testing for two canal headwater …

Assessing The Impact Of Speed Limit Reduction Near Signalized High Speed Intersections Equipped With Advance Warning Flashers: A Case Study In Nebraska, Shefang Wang

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

This thesis evaluated the effects of 5 mph and 10 mph speed limit reductions in the vicinity of high-speed, signalized intersections equipped with Advance Warning Flashers (AWF). The selected methodology involved a field study of the impact of speed limit reduction at 7 high-speed, signalized intersections with AWF, using quantile regression models developed for speed. The quantile regression models for speed indicated that reduction of the speed limit from 60 mph to 55 mph did not have significant impact on observed speed during the green time. However, it was found that speed limit reduction from 65 mph to 55 mph …

Structural Reliability Analysis Of Corroded Steel Girder Bridge, Mohammed S. Al Badran

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The natural aging, environmental impact, and appropriate design are certainly playing a serious role in safety of the bridges function. The functional safety of bridge constitutes a prime element of the transportation system serving commuters, passengers and freight. According to Federal Highway Administration, the steel bridges share represents a large amount of the United States’ bridges. In last century, the collapse of both the Silver Bridge at Point Pleasant, WV over Ohio River on December 15, 1967 and over the Mianus River Bridge in Connecticut on June 28, 1983 showed that steel corrosion has been the leading reason in these …

Stormwater Pollution Treatment Bmp Discharge Structures, Miles F. Simmons

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Structural best management practices (BMPs) are used to capture and treat stormwater runoff. Most structural BMPs provide treatment by filtering runoff through a filter media or collecting it in a detention basin and slowly discharging it over an extended period of time to allow suspended solids and associated contaminants to settle out. The purpose of this study is to design an effective outlet structure that provides adequate filtration or slows discharge to 40 hours.

A model detention basin was constructed in the Civil Engineering Hydraulics Laboratory at the University of Nebraska-Lincoln (UNL) and two full scale outlet structures were tested …

Flow And Geometry Measurements At An Active Knickpoint, Clark W. Kephart

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Channel degradation is an area of growing concern in areas of the Midwestern United States where there are large deposits of loess soils. Channel degradation occurs as a result of disturbances to the sediment load, bed soil configuration, and hydraulic characteristics of the stream (i.e. discharge, channel slope and geometry). These changes may occur suddenly or slowly over time. A given disturbance may be due to a large rain event, channel adjustments (i.e. dredging and straightening), and changes in land use around the stream (Chen et al. 1999).

A knickpoint is an abrupt drop in stream bed elevation over which …

Design Of Cable-To-Post Attachments For Use In A Non-Proprietary, High-Tension, Cable Median Barrier, Ryan Joseph Bateman

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Cable median barriers are widely used across the country to prevent cross-median crashes. Several years ago, the Midwest States Pooled Fund Program contracted with the Midwest Roadside Safety Facility (MwRSF) to develop a new, non-proprietary, high-tension, 4-cable median barrier. In the Fall of 2011 and following two failed full-scale vehicle crash tests on prototype barrier systems, it was determined that design modifications were necessary to improve barrier performance. In addition, members of the Midwest States Pooled Fund Program desired to redirect the development effort.

Both of the barrier system failures which prompted the re-design effort could be partially attributed to …