Civil and Environmental Engineering Commons^™

Saw-Cutting Guidelines For Concrete Pavements: Examining The Requirements For Time And Depth Of Saw-Cutting, Kambiz Raoufi, Tony Their, W. Jason Weiss, Jan Olek, Tommy E. Nantung

JTRP Technical Reports

Joints are placed in Portland cement concrete pavements (PCCP) to control random cracking. These joints provide a weakened plane that enables a crack to form in a controlled manner, relieving residual stresses that develop when thermal, hygral, or hydration movements are resisted by sub grade and adjoining pavement. While the concept of creating a weakened plane through saw-cutting is straightforward, determining the time and depth of the saw-cut has proven to be complicated. The goal of this project was to reduce the risk for joint raveling and random cracking. Specifically, this project has focused on: developing a procedure for determining …

Treatment Of Ro Concentrate Using Vsep Technology, Guillermo Guadalupe Delgado

Open Access Theses & Dissertations

The city of El Paso has the largest inland brackish desalination plant in the world. The Kay Bailey Hutchison (KBH) Desalting plant produces 15 million of permeate water every day. Due to the excellent quality of the water, the permeate water is blended with brackish water producing a final volume of 27.5 million gallons of water every day. With an average recovery rate of 80%, the KBH plant produces an average of 3 million gallons of concentrated brackish water that is disposed of via injection wells 23 miles from the plant.

Conventional reverse osmosis (RO) systems are not capable of …

Characterization Of A Mems Accelerometer For A Highway Health Monitoring Ultra-Low Power Sensor, Karla Cecilia Enriquez

Open Access Theses & Dissertations

With the 2009 American Recovery and Reinvestment Act, government officials recognized the need to implement automated methods that reduce the cost of assessment projects and provide a long-term solution to monitor the structural health of bridges and highways. Although important research exists in the area of non-destructive evaluation, current road health monitoring efforts continue to be costly and time consuming. This Thesis focuses on the characterization of a MEMS accelerometer intended to be the basis of a novel ultra-low power sensing system to remotely asses the condition of highways. The architecture of a sensor prototype built to validate an algorithm …

Finite Element Modeling Of Nondestructive Test Methods Used For Detection Of Delamination In Hot Mix Asphalt Pavements, Dante Mejia Munoz

Open Access Theses & Dissertations

For the simulation of detection of delamination this study focus on three NDT methods: Impact Echo, Impulse Response and Ultrasonic Surface Waves. The was evaluated and then a parametric study was elaborated.

Transition Metal Catalysts For Hydrodesulfurization Reactions Applied To Petroleum Industry, Brenda Torres

Open Access Theses & Dissertations

Catalysis plays a fundamental role in petroleum refining and basic petrochemical industries creating new routes in the development of industrial processes. Moreover, catalysis has become indispensable to the solution of environmental pollution problems and therefore on public health. World wide concerns for preservation of the environment has motivated the development of "Green" catalyst based technologies, to achieve a better utilization of petroleum resources and demands for cleaner transportation fuels. These environmental concerns have led to increasingly drastic regulations on sulfur, nitrogen and aromatics content in fuels. Sulfur content in the motor and diesel fuels is continuously reduced by regulations to …

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Building Services Engineering

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An Analytical Model For Transient Deformation Of Viscoelastically Coated Beams: Applications To Static-Mode Microcantilever Chemical Sensors, Stephen M. Heinrich, Michael J. Wenzel, Fabien Josse, Isabelle Dufour

Civil and Environmental Engineering Faculty Research and Publications

The problem governing the transient deformation of an elastic cantilever beam with viscoelastic coating, subjected to a time-dependent coating eigenstrain, is mathematically formulated. An analytical solution for an exponential eigenstrain history, exact within the context of beam theory, is obtained in terms of the coating and base layer thicknesses, the elastic modulus of the base material, the initial coating modulus, the coating relaxation percentage (0%–100%), and the time constants of the coating’s relaxation process and its eigenstrain history. Approximate formulas, valid for thin coatings, are derived as special cases to provide insight into system behavior. Main results include (1) the …

Three-Dimensional Free Surface Non-Hydrostatic Modeling Of Plunging Water With Turbulence And Air Entrained Transport, Tien Mun Yee

University of Kentucky Doctoral Dissertations

The advance in computational fluid dynamics in recent years has provided the opportunity for many fluid dynamic problems to be analyzed numerically. One such problem concerns the modeling of plunging water into a still water body, often encountered in pump stations. Air bubbles introduced into the system by the plunging jet can be a significant problem, especially when consumed into operating pumps. The classical approach to investigate the hydrodynamics of plunging jet in pump stations is by physical model studies. This approach is time consuming, tedious and costly. The availability of computational power today, along with appropriate numerical techniques, allows …

Measuring Performance Of Innovative Pavement Features, Wayne Jensen, Zhigang Shen, Cody Kluver

Department of Construction Engineering and Management: Faculty Publications

The Nebraska Department of Roads (NDOR) conducts annual examinations of the state's interstate and federal highway pavements. During these examinations, numerous indicators of pavement performance are measured directly or compiled from parameters recorded by a vehicle passing over the pavement section. Parameters are documented and analyzed for each one-tenth mile pavement segment. Seven sections where innovative features have been incorporated into the pavement were selected by the NDOR for comparison to nearby conventional pavement sections. This study used various parameters recorded by the NDOR as well as field observations to compare the performance of seven pairs of pavement sections. Each …

Missouri River Recovery Program: Fish And Wildlife Protection – Key To A Healthy River

United States Army Corps of Engineers, Omaha District

Fish and wildlife conservation on the Missouri River is one of the eight congressionally-authorized project purposes of the U.S. Army Corps of Engineers. In support of this, the Corps manages lands and waters to ensure its availability for future generations and to help preserve healthy ecosystems and biodiversity. This purpose originally focused on maintaining native and game species, but in recent years it has taken on renewed prominence with efforts to recover threatened and endangered species.

The Missouri River is a dynamic ecosystem, creating and maintaining important open water, sandbar, wetland, and forest habitat for a wide diversity of wildlife, …

Missouri River Recovery Program: Reclaiming Lost Habitat: Real Estate Program

United States Army Corps of Engineers, Omaha District

Historically, the Missouri River continually reshaped itself by eroding banks in some areas and building up islands and sandbars in other areas. The river’s dynamic nature provided plenty of habitat for native species of animals and plants.

Efforts in the 1900s to manage the river by building dams, levees and a navigation channel provided many social and economic benefits to the nation but drastically reduced the amount of habitat available for the river’s native species. Today, lack of habitat is a major reason that several Missouri River species are endangered or threatened, such as the pallid sturgeon, least tern and …

Missouri River Recovery Program: River Power To Clean Energy

United States Army Corps of Engineers, Omaha District

The overall vision of the Missouri River Recovery Program is to create a sustainable ecosystem supporting thriving populations of native species while providing for current social and economic values. Many of these social and economic values are authorized by the U.S. Congress as crucial uses of the river’s resources. Hydroelectric power is one of these authorized purposes. Hydroelectric power uses the power of the river to provide electricity to homes and businesses within the Missouri River Basin and beyond.

Missouri River Recovery Program: Missouri River Basin

United States Army Corps of Engineers, Omaha District

The Missouri River, the nation’s longest, travels more than 2,300 miles from Three Forks, Montana, to join the Mississippi River near St. Louis, Missouri. For centuries, the river has served as the center of life for the inhabitants of North America’s Great Plains. Following exploration and mapping by Lewis and Clark’s Corps of Discovery in the early 1800s, the Missouri River became the gateway to the West.

Historically, the dynamic and untamed Missouri River has produced violent floods in the spring and summer with erosive forces that ate away its banks and turned its waters the color of mud.

Since …

Missouri River Recovery Program: Emergent Sandbar Habitat

United States Army Corps of Engineers, Omaha District

This Value Engineering (VE) Report summarizes the events of the April 6-8, 2009 VE workshop facilitated by GeoVal, Inc. for the U.S. Army Corps of Engineers (USACE) Omaha District, Nebraska. The Missouri River Recovery Program - Emergent Sandbar Habitat Value Engineering Study focuses on the assessment of the Missouri River Recovery Program (MRRP) Habitat Creation Project with specific focus on the creation of emergent sandbar habitats, examining current plans and programs to seek out alternative approaches and ideas that will improve the overall performance of the program.

The MRRP seeks to mitigate near-term losses of Missouri River habitats and recover …

Missouri River Recovery Program: Putting The Pieces Together: Mrrp Main Programs

United States Army Corps of Engineers, Omaha District

The Missouri River Recovery Program (MRRP) is a comprehensive effort led by the U.S. Army Corps of Engineers in partnership with the U.S. Fish and Wildlife Service, Tribes, states, other federal agencies and non-governmental organizations to develop and implement actions to create a healthy Missouri River.

The MRRP consists of:

-The Missouri River Bank Stabilization and Navigation Project (BSNP) Fish
and Wildlife Mitigation Project

- The Amended Biological Opinion and the Corps’ Record of Decision related
to the Master Water Control Manual for the Missouri River

- The 2007 Water Resources Development Act

Each of these guiding authorities set out …

Missouri River Recovery Program: Spring Rise Monitoring

United States Army Corps of Engineers, Omaha District

The U.S. Army Corps of Engineers is committed to recover Missouri River species, while fulfilling its century-old responsibility to protect human health and safety. To aid in the recovery of the endangered pallid sturgeon, the Corps releases extra water from Missouri River reservoirs in March and May. These “spring pulses” mimic the historic river rises that resulted from melting snow on the plains and mountains, before the construction of dams on the river. Biologists believe these pulse events are necessary for Missouri River species to reproduce and survive, which is critical for a healthy river environment.

At the same time, …

Grand Challenges For Biological Engineering, Jeong-Yeol Yoon, Mark R. Riley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Biological engineering will play a significant role in solving many of the world's problems in medicine, agriculture, and the environment. Recently the U.S. National Academy of Engineering (NAE) released a document "Grand Challenges in Engineering," covering broad realms of human concern from sustainability, health, vulnerability and the joy of living. Biological engineers, having tools and techniques at the interface between living and non-living entities, will play a prominent role in forging a better future. The 2010 Institute of Biological Engineering (IBE) conference in Cambridge, MA, USA will address, in part, the roles of biological engineering in solving the challenges presented …

Impact Of Microclimatic Data Measured Above Maize And Grass Canopies On Penman‐Monteith Reference Evapotranspiration Calculations, Suat Irmak, Lameck O. Odhiambo

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Estimation of reference evapotranspiration (ET_ref) using measured microclimatic data and the Penman‐Monteith (PM) method provides a powerful means of quantifying actual plant evapotranspiration (ET_a) needed for use in various disciplines. When applying the PM method to estimate ET_ref, it is desirable to measure the required microclimatic data over a reference grass or alfalfa surface rather than above non‐reference surfaces. However, in reality, establishing and maintaining a reference surface for long periods of time is a difficult task. Other surface energy balance systems, such as the Bowen ratio energy balance system (BREBS), eddy covariance system, …

Special Issue On Evapotranspiration Measurement And Modeling, Samuel Ortega-Farias, Suat Irmak, R. H. Cuenca

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Water availability for irrigation throughout the world has been reduced in recent years due to a combination of frequent droughts and competition for water resources among agricultural, industrial, and urban users. In addition, some major agricultural areas face moderate to significant reductions of rainfall, or changes in timing of stream flow due to changes in timing of snowmelt, as a result of global climate change. Under such conditions, sophisticated irrigation water management will be required to optimize water use efficiency and maintain sufficient levels of crop productivity and quality. A key factor to achieve these targets is the estimation of …

Magnitude And Trends Of Reference Evapotranspiration Rates In South Central Nebraska: Daily, Monthly, Growing Season Total, And Annual Total, Suat Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Reference evapotranspiration (ET_ref ) is used to determine the actual water use (ET_a) rate for various crops and is one of the key variables that needs to be determined accurately for effective irrigation management. This extension circular provides information on the magnitude and temporal distribution of daily, monthly, annual, and growing season alfalfa-reference evapotranspiration (ET_ref)) in south central Nebraska. It also discusses why long-term average ET_ref values may not represent non-average years or be accurate enough for irrigation management.

The most common way to calculate actual crop water use (ET_a) for a …

Integration Of An Extended Octagonal Ring Transducer And Soil Coulterometer For Identifying Soil Compaction, Santosh Pitla, L. G. Wells, S. A. Shearer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The soil coulterometer is an “on‐the‐go” electro‐mechanical system which collects impedance force data at multiple depths using an oscillating coulter. During the initial testing (summer 2006), only vertical soil impedance force data was collected using a pressure sensor. To improve the performance of the coulterometer, an extended octagonal ring transducer was integrated into the system to collect both the horizontal and vertical impedance forces given by the soil. In the summer of 2007, data was collected using the revised sensor from a typical central Kentucky field setting in a 0.8‐ha (2‐acre) plot. Four passes were made with the coulterometer. Seventy …

Estimating Percent Residue Cover Using The Line-Transect Method, David P. Shelton, Paul J. Jasa

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Leaving crop residue on the soil surface is one of the easiest and most cost-effective methods of reducing soil erosion. Research in Nebraska and other midwestern states has shown that leaving as little as 20 percent of the soil surface covered with crop residue can reduce soil erosion by one-half of what it would be from residue-free conditions. Greater amounts of residue cover will further reduce erosion. Many Conservation Plans specify crop residue management or residue left on the soil surface as the primary erosion control method. Generally, the amount of cover required after planting ranges from 30 percent to …

Effect Of Phase Countdown Timers On Queue Discharge Characteristics Under Heterogeneous Traffic Conditions, Anuj Sharma

Anuj Sharma Publications

Analysis of queue discharge characteristics at signalized intersections is a primary component of traffic signal analysis and design. On the basis of previous studies, mainly conducted in homogeneous traffic conditions, the discharge headway is assumed to be high at the start of green for the first few vehicles, mainly because of start-up lost times, and is also assumed to reach the minimum value by the fourth or fifth vehicle in the queue. The minimum headway is expected to continue until the end of the queue. However, this may not be the case under heterogeneous traffic conditions, such as those in …

Special Issue On Evapotranspiration Measurement And Modeling, Samuel Ortega-Farias, Suat Irmak, R. H. Cuenca

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Water availability for irrigation throughout the world has been reduced in recent years due to a combination of frequent droughts and competition for water resources among agricultural, industrial, and urban users. In addition, some major agricultural areas face moderate to significant reductions of rainfall, or changes in timing of stream flow due to changes in timing of snowmelt, as a result of global climate change. Under such conditions, sophisticated irrigation water management will be required to optimize water use efficiency and maintain sufficient levels of crop productivity and quality. A key factor to achieve these targets is the estimation of …

Regional Co2 And Latent Heat Surface Fluxes In The Southern Great Plains: Measurements, Modeling, And Scaling, W. J. Riley, Sebastien C. Biraud, Margaret S. Torn, Marc L. Fischer, David P. Billesbach, Joe A. Berry

Department of Agricultural and Biological Systems Engineering: Faculty Publications

[1] Characterizing net ecosystem exchanges (NEE) of CO2 and sensible and latent heat fluxes in heterogeneous landscapes is difficult, yet critical given expected changes in climate and land use. We report here a measurement and modeling study designed to improve our understanding of surface to atmosphere gas exchanges under very heterogeneous land cover in the mostly agricultural U.S. Southern Great Plains (SGP). We combined three years of site-level, eddy covariance measurements in several of the dominant land cover types with regional-scale climate data from the distributed Mesonet stations and Next Generation Weather Radar precipitation measurements to calibrate a land surface …

A Sequential Bayesian Approach For Hydrologic Model Selection And Prediction, Kuo-Lin Hsu, Hamid Moradkhani, Soroosh Sorooshian

Civil and Environmental Engineering Faculty Publications and Presentations

When a single model is used for hydrologic prediction, it must be capable of estimating system behavior accurately at all times. Multiple-model approaches integrate several model behaviors and, when effective, they can provide better estimates than that of any single model alone. This paper discusses a sequential model fusion strategy that uses the Bayes rule. This approach calculates each model's transient posterior distribution at each time when a new observation is available and merges all model estimates on the basis of each model's posterior probability. This paper demonstrates the feasibility of this approach through case studies that fuse three hydrologic …

Feedback Between Residual Circulations And Sediment Distribution In Highly Turbid Estuaries: An Analytical Model, Stefan A. Talke, Huib E. De Swart, H. M. Schuttelaars

Civil and Environmental Engineering Faculty Publications and Presentations

Motivated by field studies of the Ems estuary which show longitudinal gradients in bottom sediment concentration as high as O(0.01 kg/m⁴), we develop an analytical model for estuarine residual circulation based on currents from salinity gradients, turbidity gradients, and freshwater discharge. Salinity is assumed to be vertically well mixed, while the vertical concentration profile is assumed to result from a balance between a constant settling velocity and turbulent diffusive flux. Width and depth of the model estuary are held constant. Model results show that turbidity gradients enhance tidally averaged circulation upstream of the estuarine turbidity maximum (ETM), …

An Idealized Model And Systematic Process Study Of Oxygen Depletion In Highly Turbid Estuaries, Stefan A. Talke, Huib E. De Swart, Victor De Jonge

Civil and Environmental Engineering Faculty Publications and Presentations

The sensitivity of oxygen depletion in turbid estuaries to parameters like freshwater discharge, depth, and sediment availability is investigated using an idealized model. The model describes tidally averaged circulation and suspended sediment concentration (SSC), which are input into an advection–diffusion sink module of dissolved oxygen (DO). Based on the analysis of field data collected in the Ems estuary, the modeled oxygen depletion rates are proportional to SSC. The model is calibrated to the observed variation of DO with SSC and temperature. Modeled DO closely tracks changes to the estuarine turbidity zone (ETZ): increased channel depth, decreased freshwater discharge, and decreased …

The Potential Contribution Of Organic Salts To New Particle Growth, Kelley Barsanti, Peter H. Mcmurry, J. N. Smith

Civil and Environmental Engineering Faculty Publications and Presentations

Field and lab measurements suggest that low-molecular weight (MW) organic acids and bases exist in accumulation and nucleation mode particles, despite their relatively high pure-liquid vapor pressures. The mechanism(s) by which such compounds contribute to the mass growth of existing aerosol particles and newly formed particles has not been thoroughly explored. One mechanism by which low- MW compounds may contribute to new particle growth is through the formation of organic salts. In this paper we use thermodynamic modeling to explore the potential for organic salt formation by atmospherically relevant organic acids and bases for two system types: one in which …

An H-Adaptive Finite-Element Technique For Constructing 3d Wind Fields, Darrell Pepper, Xiuling Wang

Mechanical Engineering Faculty Research

An h-adaptive, mass-consistent finite-element model (FEM) has been developed for constructing 3D wind fields over irregular terrain utilizing sparse meteorological tower data. The element size in the computational domain is dynamically controlled by an a posteriori error estimator based on the L2 norm. In the h-adaptive FEM algorithm, large element sizes are typically associated with smooth flow regions and small errors; small element sizes are attributed to fast-changing flow regions and large errors. The adaptive procedure employed in this model uses mesh refinement–unrefinement to satisfy error criteria. Results are presented for wind fields using sparse data obtained from two regions …