Civil and Environmental Engineering Commons^™

Effectiveness Study Of Non-Nuclear Gauge For Hot Mix Asphalt (Hma) Pavement Construction, Ziqing Zhuang

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Density is an important measure for hot-mix asphalt (HMA) pavement quality control. Traditionally, the nuclear gauge method is widely used in pavement density testing. However, some disadvantages of nuclear gauges (such as the handling, storage, and transportation of radioactive materials) have created the need of non-nuclear technology. This thesis evaluated the Pavement Quality Indicator (PQI) model 301, which was promised to be more efficient than the nuclear method. The PQI utilizes many electrical impedance principles by using the current going through the pavement to determine its density and moisture content. Test data were collected in the field during pavements, and …

Effectiveness Study On Temporary Pavement Marking Removals Methods, Koudous Kabassi

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

This study was conducted to identify effective temporary marking removal methods and procedures on concrete and asphalt pavements. Pavement markings provide guidance to road travelers and can lead to accidents when not properly removed. Current state guidelines on removal do not provide clear and objective methods of measurement. After testing the most common removal methods, this research concluded that removing markings by chemical was not only cost and results-oriented effective compared to other methods, but it was also safe to the environment and road users. Finally, a baseline of measurements was developed for this project, along with the feasibility of …

Streambank Erosion And Instability Induced By Groundwater Seepage, Taber L. Midgley, Garey A. Fox, Glenn V. Wilson, Derek M. Heeren, Andrew Simon, Eddy J. Langendoen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Excessive sediment is one of the most common surface water pollutants. It diminishes water quality and destroys aquatic habitat. Streambank erosion is known to be a major source of sediment in streams and rivers, contributing as much as 80% of the total sediment load in some watersheds. Little work has been done to study the effects of seepage on streambank erosion and failure. Prior research, primarily in the laboratory under well-defined and controlled conditions, has examined seepage as a mechanism for bank erosion, but more needs to be done to validate conclusions derived from the laboratory with field data. This …

Performance Rating Of De-Icing Chemicals For Winter Operations, Barbara M. Gerbino-Bevins

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

The cost of deicing chemicals is a significant part of the Nebraska Department of Road's winter maintenance budget. Many products are available for use in highway and bridge deicing and new products are introduced each year. The objectives of this research are to develop a laboratory test to evaluate the performance of chemical deicers, to investigate national, state, and local standards, and to develop best maintenance practices to optimize the use of chemical deicers.

This research project consists of two phases:

Phase 1: conduct a literature survey to find data from existing laboratory tests used to evaluate deicer performance.

Phase …

Application Of Shredded-Tire Biofilter And Membrane Bioreactor For Greywater Reclamation, Meng Hu

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

Water scarcity is a pressing global issue. Greywater (GW) reclamation is a viable option to reduce freshwater demand. The objectives of this work were to: a) evaluate the feasibility of the combination of shredded tire biofilter (STB) technology and membrane bioreactor (MBR) technology in GW reclamation; b) study the effects of various parameters on STB performance; and c) understand the fouling mechanisms to lower the energy consumption in MBRs. Bench-scale STBs and MBRs (flat-sheet membranes) were constructed to address the first two objectives, while an independent membrane (hollow-fiber membranes) fouling experiment was designed for the third objective.

It was found …

Applied And Mechanistic Studies Of Microbial 17beta-Estradiol Degradation, Zhongtian Li

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

The presence of natural estrogens, a class of endocrine disrupting compounds, in water has caused increasing concerns over their adverse impacts on the health of aquatic eco-systems and human beings. In this study, adsorption characteristics of two natural estrogens, 17β-estradiol (E2) and estrone (E1), on granular activated carbon (GAC) were investigated in isotherm tests and in a GAC column. The GAC column was then converted to a biologically active carbon (BAC) column and the removal efficiency of E2 and its primary biodegradation intermediate E1 were monitored. During BAC operation, the impacts of various reactor operation parameters, such as the carbon …

Roadside Grading Guidance, Kevin D. Schrum

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

Provisions for the design of roadside foreslopes are not readily available, and as a result, engineering judgment is often employed. Unfortunately, this can lead to inconsistent designs, where, inevitably, some designs will be too costly and other designs will be too dangerous. Therefore, a design guide was created to lend consistency to the design of these foreslopes while maintaining the most economical and safe design.

This design guide was prepared after conducting a benefit-cost analysis using the Roadside Safety Analysis Program (RSAP). A large test matrix was developed in an attempt to simulate the most possible scenarios, leaving interpolation to …

Theoretical And Numerical Research On Sediment Transport In Pressurized Flow Conditions, Zhaoding Xie

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

Research of river bed erosion is an important part of designing bridges and transportation networks since the stability and hydrodynamic response of bridges critically depends on river bed scour. The engineering designers traditionally focus on the local scour around hydraulic structures, such as piers and abutments, in open channel flow. The pressurized scour under a submerged bridge deck is seldom researched.

In this study, the commercial CFD codes, FLOW3D and STARCCM+, are adopted to simulate pressure scour under a bridge deck with six girders. Several limitations for FLOW3D are found during its application of sediment transport model: a) the scour …

A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal, Sarah M. Asio

Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research

The application of traditional approaches to the design of efficient facilities can be tedious and time consuming when uncertainty and a number of constraints exist. Queuing models and mathematical programming techniques are not able to capture the complex interaction between resources, the environment and space constraints for dynamic stochastic processes. In the following study discrete event simulation is applied to the facility planning process for a grain delivery terminal. The discrete event simulation approach has been applied to studies such as capacity planning and facility layout for a gasoline station and evaluating the resource requirements for a manufacturing facility. To …

The Effects Of Pedestrian Countdown Timers On Safety And Efficiency Of Operations At Signalized Intersections, Jacob N. Schmitz

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

Pedestrian countdown timers are becoming common at urban and suburban intersections. The added information that pedestrian countdown timers provide to pedestrians can also be used by approaching drivers. A before and after case study on the effects that pedestrian countdown timers have on safety and efficiency of operations was performed at two signalized intersections in Lincoln, Nebraska. The effects on both drivers and pedestrians were analyzed. Performance measures for pedestrian analysis include pedestrian compliance and average pedestrian walking speed. Performance measures for the driver analysis include probability of stopping and speed at the stop bar of vehicles during the yellow …

Developing Deterioration Models For Nebraska Bridges, George Morcous

Nebraska Department of Transportation: Research Reports

No abstract provided.

Identifying Changes In Climatic Trends And The Fingerprints Of Landuse And Landcover Changes In The High Plains Of The Usa, Denis Mutiibwa

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Human activities such as conversion of natural ecosystem to croplands and urban-centers, deforestation and afforestation impact biophysical properties of land surface such as albedo, energy balance, and surface roughness. Alterations in these properties affect the heat and moisture exchanges between the land surface and atmospheric boundary layer. The objectives of this research were; (i) to quantitatively identify the High plains’ regional climate change in temperatures over the period 1895 to 2006, (ii) detect the signatures of anthropogenic forcing of LULC changes on the regional climate change of the High Plains, and (iii) examine the trends in evolving regional latent heat …

An Enzymatic Treatment Of Soil-Bound Prions Effectively Inhibits Replication, Samuel Saunders, Jason C. Bartz, Kurt C. Vercauteren, Shannon L. Bartelt-Hunt

Department of Civil and Environmental Engineering: Faculty Publications

Chronic wasting disease (CWD) and scrapie can be transmitted through indirect environmental routes, possibly via soil, and a practical decontamination strategy for prion-contaminated soil is currently unavailable. In the laboratory, an enzymatic treatment under environmentally relevant conditions (22°C, pH 7.4) can degrade soil-bound PrPSc below the limits of Western blot detection. We developed and used a quantitative serial protein misfolding cyclic amplification (PMCA) protocol to characterize the amplification efficiency of treated soil samples relative to controls of known infectious titer. Our results suggest large (104- to >106-fold) decreases in soil-bound prion infectivity following enzyme treatment, demonstrating that a mild enzymatic …

Using Laser Scanning Cytometry To Investigate The Transport Of Nano-Scale Particles In Porous Media, Ryan May

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

The increased production of nanomaterials in recent years has been unprecedented. Given their potential toxicity, understanding the mechanisms controlling the transport of nanoparticles in the subsurface is important. In this study, a technique was developed for using a Laser Scanning Cytometer (LSC) to visualize and quantify the stable attachment of nano-scale particles. Experiments using three different size particles, 510 nm, 210 nm and 57 nm, in conjunction with a flow cell system containing saturated glass beads under varied injection duration, solution chemistry, Darcy velocity and solids content were performed. A technique for using the LSC data to develop spatial distributions …

Effect Of Information On Driver's Risk At The Onset Of Yellow, Nathaniel P. Burnett

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

Intersection crashes average approximately 8,500 fatal and 900,000 injury accidents a year (1). At the onset of yellow at a high speed signalized intersection, a driver may encounter a region of the intersection approach, where they can neither stop safely nor be able to clear the intersection before the red indication. A wrong decision to stop when it would have been safer to proceed can lead to a severe rear-end collision. Conversely, a wrong decision to proceed through the intersection could lead to the driver running the red light and possibly causing a right angle collision. The traditional …

Computational Microstructure Modeling Of Asphalt Mixtures Subjected To Rate-Dependent Fracture, Francisco Aragao

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

Computational microstructure models have been actively pursued by the pavement mechanics community as a promising and advantageous alternative to limited analytical and semi-empirical modeling approaches. The primary goal of this research is to develop a computational microstructure modeling framework that will eventually allow researchers and practitioners of the pavement mechanics community to evaluate the effects of constituents and mix design characteristics (some of the key factors directly affecting the quality of the pavement structures) on the mechanical responses of asphalt mixtures. To that end, the mixtures are modeled as heterogeneous materials with inelastic mechanical behavior. To account for the complex …

Evaluation Of The In-Service Safety Performance Of Safety-Shape And Vertical Concrete Barriers, Francisco Daniel Albuquerque

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

Roadside concrete barriers have been widely used to protect errant motorists from hitting roadside hazards or obstacles. Two concrete barrier profiles, vertical and safety-shape, have been used for this purpose. The safety-shape profile has been shown to produce excessive vehicle climbing which tends to increase rollover propensity. The vertical profile, on the other hand, does not cause vehicle climbing, but it does produce higher lateral forces which may produce higher injury levels.

The objective of this research is to investigate which barrier profile is the safest based on real-world vehicle crash data. The safest barrier profile is defined as the …

Delayed Composite Action Coupled With Post-Tensioning For Cast In Place Bridge Deck Systems, Nathanael J. Toenies

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

Cast-in-place bridge decks are known to have transverse cracking early in the life of the bridge due to shrinkage and temperature effects. The cracks result from immediate composite behavior between the girder and the deck. For steel bridges, this bond is caused by shear studs welded to the steel beams and embedded in the cast-in-place deck. Prevention or closure of these cracks could greatly increase the durability of the bridge.

The following research focuses on introducing a system that will have delayed composite action, allowing strain in the concrete before it becomes composite with the girder. The system is meant …

Computational Micromechanics Modeling Of Damage-Dependent Bituminous Composites Based On Two-Way Coupled Multiscale Approach, Jamilla Lutif

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

This study presents a multiscale computational model with its verification and validation to mechanical behavior predictions of bituminous composites that are subject to fracture damage. Bituminous composites are classical examples of multi-phase composites in different length scales. The understanding of the mechanical behavior of asphaltic media has been a challenge to the pavement mechanics community due to multiple complexities involved: heterogeneity, anisotropy, nonlinear inelasticity, and damage growth in multiple forms. To account for this problem in an accurate and efficient way, this study proposes the use of the two-way coupled multiscale computational modeling technique.

The two-way coupled multiscale model is …

Effectiveness Study On Temporary Pavement Marking Removals Methods, Yong Cho, Jae-Ho Pyeon

Nebraska Department of Transportation: Research Reports

This study was conducted to identify effective temporary marking removal methods and procedures on concrete and asphalt pavements. Pavement markings provide guidance to road travelers and can lead to accidents when not properly removed. Current state guidelines on removal do not provide clear and objective methods of measurement. After testing the most common removal methods, this research concluded that removing markings by chemical was not only cost and results-oriented effective compared to other methods, but it was also safe to the environment and road users. Finally, a baseline of measurements was developed by the research team for this project, along …

Impact Of 0.7 Inch Diameter Strands On Nu I-Grinders, Maher K. Tadros, George Morcous

Nebraska Department of Transportation: Research Reports

No abstract provided.

Non-Nuclear Method For Density Measurements, Yong-Rak Kim, Yong Cho

Nebraska Department of Transportation: Research Reports

Quality control (QC) and quality assurance (QA) are necessary to ensure fulfillment and compliance to specifications, guidelines, manuals, and programs which outline methods and requirements during construction. Density, an important part of quality control, can be used to evaluate the quality of Hot Mix Asphalt (HMA) and soil compaction. This study investigated new technologies used for QC and QA by comparing the Pavement Quality Indicator (PQI) model 301 with a nuclear gauge and core sample measurements for HMA. For soil QC and QA, non-nuclear technologies—the Electrical Density Gauge (EDG), the Moisture Density Indicator (MDI), and the Light Weight Deflectometer (LWD)—were …

The Green, Blue And Grey Water Footprint Of Crops And Derived Crop Products, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

Abstract. This study quantifies the green, blue and grey water footprint of global crop production in a spatially-explicit way for the period 1996–2005. The assessment improves upon earlier research by taking a high-resolution approach, estimating the water footprint of 126 crops at a 5 by 5 arc minute grid. We have used a grid-based dynamic water balance model to calculate crop water use over time, with a time step of one day. The model takes into account the daily soil water balance and climatic conditions for each grid cell. In addition, the water pollution associated with the use of nitrogen …

Missouri River Recovery Program Power Point Presentation

United States Army Corps of Engineers, Omaha District

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Ecosystem Management Of The Missouri River From Gavins Point Dam To Ponca State Park, Nebraska, Robert S. Nebel

United States Army Corps of Engineers, Omaha District

•Authorized by a 1978 amendment to the National Parks and Recreation Act (PL 95- 625) which amended the Wild and Scenic Rivers Act of 1968 (PL 90-542)

• Corps is authorized to construct recreational development, bank stabilization, and other recreational river features as necessary to support the values for which the river was designated

• Life-of-project funding ceiling of $21 million; approximately $3.2 million spent to date

• The Corps and National Park Service signed a 1980 Cooperative Agreement outlining each agency's responsibilities

• The General Management Plan has recently been updated (1999) with an environmental emphasis

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National Water Footprint Accounts: The Green, Blue And Grey Water Footprint Of Production And Consumption. Volume 1: Main Report, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

This study quantifies and maps the water footprints of nations from both a production and consumption perspective and estimates international virtual water flows and national and global water savings as a result of trade. The entire estimate includes a breakdown of water footprints, virtual water flows and water savings into their green, blue and grey components. The main finding of the study can be summarized as:

The global water footprint in the period 1996-2005 was 9087 Gm3/yr (74% green, 11% blue, 15% grey). Agricultural production contributes 92% to this total footprint.

About one fifth of the global water footprint relates …

National Water Footprint Accounts: The Green, Blue And Grey Water Footprint Of Production And Consumption, Volume 2: Appendices, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

Contents

Appendix I. The water footprint of national production (Mm³/yr)

Appendix II. Virtual-water flows related to trade in crop, animal and industrial products, per country (Mm³/yr)

Appendix III. International virtual-water flows per product category (Mm³/yr)

Appendix IV. National water saving related to trade in agricultural and industrial products per country (Mm³/yr)

Appendix V. Global water saving related to trade in agricultural and industrial products, per product (Mm³/yr)

Appendix VI. The average water footprint per ton of commodity per country, weighted based on origin (WF* in m³/ton)

Appendix VII. …

Investigation Of The Use Of Multi-Criteria Decision-Making Tools For Management Of An Urbanizing Watershed, Reed C. Colton

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

The regulation of non-point pollution sources (e.g. agricultural runoff and stormwater discharges) as mandated by the 1972 Clean Water Act, forced a fundamental paradigm shift from “end of the pipe” pollution control to a watershed management approach. Multiple jurisdictions and often conflicting objectives make it difficult to reach stakeholder consensus and execute watershed management decisions. To facilitate decision making when multiple and/or conflicting objectives exist, Multi-Criteria Decision-Making (MCDM) tools were developed for diverse applications, and potentially could be used to facilitate watershed management.

The overall objective of this thesis was to evaluate MCDM tool use to facilitate community-based management of …

Economic Input–Output Life Cycle Assessment Of Water Reuse Strategies In Residential Buildings And Communities, Derek J. Gardels

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

The objective of this study was to determine the environmental sustainability and economic feasibility of five water reuse designs using economic input-output life cycle assessments and benefit/cost analyses. These five water reuse designs were evaluated for four regions of the United States including the Northwest (Seattle), Southwest (Scottsdale), Midwest (Omaha), and Southeast (Tampa). The water reuse designs include a greywater reuse system with no treatment for sub-surface landscape irrigation for a single-family residential house (Model 1), an indoor greywater reuse system with treatment for toilet flushing and laundry washing for a single-family residential house (Model 2), a hybrid untreated greywater …