Civil and Environmental Engineering Commons^™

Calibrating The Robertson’S Platoon Dispersion Model On A Coordinated Corridor With Advance Warning Flashers, Zhao Li, Laurence Rilett, Ernest Tufuor

Department of Civil and Environmental Engineering: Faculty Publications

Platoon dispersion (PD) is the foundation of traffic signal coordination in an urban traffic network. PD describes the phenomenon by which vehicles depart from an upstream intersection as a platoon and begin to disperse before they arrive at the downstream intersection. Recently, advance warning flashers (AWFs) have been applied in many high-speed corridors. There is a need to update the traditional PD model to include the effect of AWFs. This paper examines the traffic flow dispersion patterns when an AWF is present and tests the hypothesis that the AWF will affect PD on a coordinated signal corridor. Platoon vehicles, which …

Spatial And Temporal Changes In Maize And Soybean Grain Yield, Precipitation Use Efficiency, And Crop Water Productivity In The U.S. Great Plains, Meetpal S. Kukal, S. Irmak

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Sustainable agricultural utilization of the limited water resources demands improvements in understanding the changes in crop water productivity (CWP) in space and time, which is often presented as a potential solution to relieve the growing pressure on fresh water resources. In addition, crop yield needs to be studied in relation to precipitation received annually and during the growing season for its contribution to reduce irrigation water requirements, which is quantified through precipitation use efficiency (PUE). Hence, systematic quantifications, mapping, and analyses of large-scale CWP and PUE levels are needed. This study aims to quantify long-term (1982-2013) information on grain yield, …

Large Co2 And Ch4 Emissions From Polygonal Tundra During Spring Thaw In Northern Alaska, Naama Raz-Yaseef, Margaret S. Torn, Yuxin Wu, David P. Billesbach, Anna K. Liljedahl, Timothy J. Kneafsey, Vladimir E. Romanovsky, David R. Cook, Stan D. Wullschleger

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The few prethaw observations of tundra carbon fluxes suggest that there may be large spring releases, but little is known about the scale and underlying mechanisms of this phenomenon. To address these questions, we combined ecosystem eddy flux measurements from two towers near Barrow, Alaska, with mechanistic soil-core thawing experiment. During a 2 week period prior to snowmelt in 2014, large fluxes were measured, reducing net summer uptake of CO₂ by 46% and adding 6% to cumulative CH₄ emissions. Emission pulses were linked to unique rain-on-snow events enhancing soil cracking. Controlled laboratory experiment revealed that as surface ice …

Cive 463: Traffic Engineering—A Peer Review Of Teaching Project Benchmark Portfolio, John Sangster

UNL Faculty Course Portfolios

This course portfolio documents the backward design of a senior-level design elective course in traffic engineering within the Department of Civil Engineering at the University of Nebraska. An extensive discussion of stakeholder needs for the course is followed by an analysis of formative and summative feedback assessments that are designed to meet the needs of a heterogeneous group of students in the course. As a senior-level design elective, there is a wide variety of interest levels among participants in the course, varying from those who have experience with internships in the topic and offer letters to conduct work in this …

Invasive Species Impacts On Infrastructure, Invasive Species Advisory Committee

National Invasive Species Council

Executive Summary

Invasive species represent one of the most significant threats to ecosystems, human and animal health, infrastructure, the economy, and cultural resources. Because potentially invasive, non-native species typically enter the United States through ports of entry in urban environments, some of the first observable impacts may be to infrastructure, yet little is known about the economic costs associated with these impacts to the “built” environment. In addition, federal agencies currently lack the authority necessary to effectively prevent, eradicate, and control invasive species that impact the human-built environment. This lack of authority prevents rapid response to some of the most …

Effectiveness Study Of Unl’S Crack Routing Device (Crd) –Phase Ii, Changbum Ahn, Yong Cho, Hamed N. Rafsanjani, Heath Wiley

Nebraska Department of Transportation: Research Reports

This project evaluated the crack routing device (CRD) for effectiveness in improving current crack-cutting practices and for possible adoption as a standard in the Nebraska Department of Roads (NDOR). To enact these evaluations of CRD, the research team collaborated with NDOR to conduct surveys and field tests. Given the positive results obtained from this project, improved road-maintenance practices are anticipated when CRD is used, and this research therefore recommends the adoption of CRD in crack-routing work.

Condition Factor Calibration For Load And Resistance Factor Rating Of Steel Girder Bridges, Pranav M. Shakya

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

The Load and Resistance Factor Rating (LRFR) is a reliability-based rating procedure complementary to the Load and Resistance Factor Design (LRFD). The intent of LRFR is to provide consistent reliability for all bridges regardless of in-situ condition. The primary difference between design and rating is the uncertain severity and location of deterioration, including the potential future loss of strength for an element already evidencing deterioration. Ostensibly, these uncertainties are accounted for by applying an additional strength reduction factor: the condition factor, ϕ_c. Currently, condition factors are nominally correlated to the condition of the member, which can be Good, …

Continuous Long-Term Health Monitoring Using Ultrasonic Wave Propagation, Ece Erdogmus

Nebraska Department of Transportation: Research Reports

No abstract provided.

M049 Effects Of Compaction And Soil Moisture On American Burying Beetles, W. Wyatt Hoback

Nebraska Department of Transportation: Research Reports

Silphid beetles in the genus Nicrophorus bury themselves during periods of inactivity, however, the influence of soil characteristics on burial behavior remains unclear. We examined soil preferences of the federally endangered Nicrophorus americanus, as well as of N. carolinus, N. marginatus, N. obscurus, and N. orbicollis, in a series of experiments. Differences in burial depth by sex were found for N. carolinus, N. marginatus, and N. obscurus, which are diurnal species. Both sexes of N. americanus bury to a mean depth of 18 cm. Soil preferences tested included sand versus sandy loam versus sandy loess, degrees of soil moisture, and …

Evaluation Of Dowel Bar Inserter Practices In Pcc Pavements With Magnetic Tomography Technology, Farshad Fallah, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

Dowel Bar Inserters (DBI) are automated mechanical equipment that position dowel bars in Portland Cement Concrete (PCC) after concrete is placed. Compared to the alternative approach, which is using dowel baskets, DBIs offer advantages in cost and speed of construction. However, as dowel bars are not anchored to the subgrade similar to dowel baskets, there is a concern about the quality of dowel placement using this equipment. Improper placement of dowel bars can lead to reduced load transfer between slabs, which results in pavement distresses such as faulting and spalling at joints. To determine the accuracy of dowel placement by …

Modeling Streambank Erosion On Composite Streambanks On A Watershed Scale, A. R. Mittelstet, D. E. Storm, G. A. Fox, P. M. Allen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Streambanks can be a significant source of sediment and phosphorus to aquatic ecosystems. Although the streambank-erosion routine in the Soil and Water Assessment Tool (SWAT) has improved in recent versions, the recently developed routine in SWAT 2012 has undergone limited testing, and the lack of site or watershed specific streambank data increases the uncertainty in the streambank-erosion predictions. There were two primary objectives of this research: (1) modify and test the 2012 SWAT streambank-erosion routine on composite streambanks, and (2) compare SWAT default and field-measured channel parameters and assess their influence on predicted streambank erosion. Three modifications were made to …

Spatial Distribution Of Antibiotic Resistance In Soils Receiving Beef Feedlot Runoff, Scott Speicher

Department of Environmental Engineering: Theses and Other Student Research

A study was conducted to provide new insight on the potential contribution to antibiotic resistance from the land application of beef feedlot runoff to soil. This study reports the distribution and quantity of antibiotic resistant bacteria (ARBs), fecal indicator bacteria (FIB), and antibiotic resistance genes (ARGs) in soil from (i) a field receiving long-term application of beef feedlot runoff holding pond effluent and (ii) a cool-season pasture with no history of supplemental manure application.

Soil samples were collected June 2015 at the U.S. Meat Animal Research Center near Clay Center, Nebraska. A response surface sampling design (RSSD) model based on …

Species Distribution Model For Swift Fox In Nebraska, Lucia Corral Hurtado

Nebraska Department of Transportation: Research Reports

No abstract provided.

Quantifying An Aquifer Nitrate Budget And Future Nitrate Discharge Using Field Data From Streambeds And Well Nests, Troy E. Gilmore, David P. Genereux, Kathleen M. Farrell, Helena Mitasova

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Novel groundwater sampling (age, flux, and nitrate) carried out beneath a streambed and in wells was used to estimate (1) the current rate of change of nitrate storage, dS_NO3 /dt, in a contaminated unconfined aquifer, and (2) future [NO₃^–]_FWM (the flow-weighted mean nitrate concentration in groundwater discharge) and f_NO3 (the nitrate flux from aquifer to stream). Estimates of dS_NO3 /dt suggested that at the time of sampling (2013) the nitrate storage in the aquifer was decreasing at an annual rate (mean = –9 mmol/m²yr) equal …

Benchmark Levels For The Consumptive Water Footprint Of Crop Production For Different Environmental Conditions: A Case Study For Winter Wheat In China, La Zhuo, Mesfin Mekonnen, Arjen Y. Hoekstra

Daugherty Water for Food Global Institute: Faculty Publications

Meeting growing food demands while simultaneously shrinking the water footprint (WF) of agricultural production is one of the greatest societal challenges. Benchmarks for the WF of crop production can serve as a reference and be helpful in setting WF reduction targets. The consumptive WF of crops, the consumption of rainwater stored in the soil (green WF), and the consumption of irrigation water (blue WF) over the crop growing period varies spatially and temporally depending on environmental factors like climate and soil. The study explores which environmental factors should be distinguished when determining benchmark levels for the consumptive WF of crops. …

Effect Of Rainfall Timing And Tillage On The Transport Of Steroidhormones In Runoff From Manure Amended Row Crop Fields, Sagor Biswas, William L. Kranz, Charles A. Shapiro, Daniel D. Snow, Shannon L. Bartelt-Hunt, Mitiku Mamo, David D. Tarkalson, Tian C. Zhang, David P. Shelton, Simon J. Van Donk, Terry L. Mader

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Runoff generated from livestock manure amended row crop fields is one of the major pathways of hormone transport to the aquatic environment. The study determined the effects of manure handling, tillage methods, and rainfall timing on the occurrence and transport of steroid hormones in runoff from the row crop field. Stockpiled and composted manure from hormone treated and untreated animals were applied to test plots and subjected to two rainfall simulation events 30 days apart. During the two rainfall simulation events, detection of any steroid hormone or metabolites was identified in 8–86% of runoff samples from any tillage and manure …

Anisotropic Contrast Optical Microscope, D. Peev, T. Hofmann, N. Kananizadeh, S. Beeram, E. Rodriguez, S. Wimer, K.B. Rodenhausen, C.M. Herzinger, T. Kasputis, E. Pfaunmiller, A. Nguyen, Rafal Korlacki, A. Pannier, Y. Li, E. Schubert, D. Hage, M. Schubert

Department of Civil and Environmental Engineering: Faculty Publications

An optical microscope is described that reveals contrast in the Mueller matrix images of a thin, transparent, or semi-transparent specimen located within an anisotropic object plane (anisotropic filter). The specimen changes the anisotropy of the filter and thereby produces contrast within the Mueller matrix images. Here we use an anisotropic filter composed of a semi-transparent, nanostructured thin film with sub-wavelength thickness placed within the object plane. The sample is illuminated as in common optical microscopy but the light is modulated in its polarization using combinations of linear polarizers and phase plate (compensator) to control and analyze the state of polarization. …

How Acoustics In California High Performance Schools Relate To Student Achievement, Devin K. Wong

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

This research project seeks to determine if students attending K–12 schools meeting a minimum standard of high performance classroom conditions in the state of California do evidence higher scholastic achievement, based on publically available results on state-wide standardized tests. In three phases, a subset of 200+ schools applying for grants dedicated to building high performance schools over the past decade was correlated with an existing database of achievement scores for all public schools in California. The criteria utilized to specify high performance classrooms was provided by the California High Performance Initiative (HPI) Grant program. Academic achievement was evaluated on a …

Development Of A Transition Between An Energy-Absorbing Concrete Barrier And A Rigid Concrete Butress, Tyler L. Schmidt, Ronald K. Faller, Jennifer D. Schmidt, John D. Reid, Robert W. Bielenberg, Scott Rosenbaugh

Nebraska Department of Transportation: Research Reports

From 2010 to 2015, MwRSF researchers developed the RESTORE barrier, which is a restorable MASH TL-4 median barrier with a steel and concrete rail supported by elastomer posts and steel skids. The research effort reported herein describes the initial development of a transition from the RESTORE barrier to a rigid TL-4 concrete buttress.

The previously-developed RESTORE barrier LS-DYNA model was validated against three full-scale vehicle crash tests. Several design concepts were generated through a series of brainstorming efforts. The primary transition concept consisted of a pin and loop connection between the RESTORE barrier and rigid concrete buttress, which was designed …

Performance Of Advance Warning Systems In A Coordinated System, Li Zhao, Laurence R. Rilett, Ernest Tufuor, Waleed Khan, Christopher Lefrois

Nebraska Department of Transportation: Research Reports

The Advance Warning System (AWS), developed by the Nebraska Department of Roads (NDOR) has proven to be effective at improving traffic safety at isolated signalized intersections. However, the effectiveness of the system has not been analyzed at signalized intersections operating in a coordinated mode. This project analyzed AWS on arterials where the signals operate in a coordinated mode. The test bed consisted of nine sites, which are located at five successive coordinated signalized intersections on Highway 281 in Grand Island, Nebraska. A non-intrusive data collection system was used to collect a continuous traffic stream of data up to 1200 ft …

Research On High-Rap Asphalt Mixtures With Rejuvenators And Wma Additives, Hamzeh Haghshenas, Hesanaddin Nabizadeh, Yong-Rak Kim, Kommidi Santosh

Nebraska Department of Transportation: Research Reports

No abstract provided.

Wetlands And Coastal Systems: Protecting And Restoring Valuable Ecosystems, C. T. Agouridis, K. R. Douglas-Mankin, A. C. Linhoss, A. R. Mittelstet

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Wetlands and coastal systems are unique, highly productive, and often threatened landscapes that provide a host of services to both humans and the environment. This article introduces a five-article Wetlands and Coastal Systems Special Collection that evolved from a featured session at the 2015 ASABE Annual International Meeting in New Orleans, Louisiana. The Collection provides perspectives on tools and techniques for enhancing the protection and restoration of wetlands and coastal systems with emphasis on vegetation, hydrology, water quality, and planning. Topics span the Florida Everglades (two articles) and Virginia floodplain (one article) wetland systems and include remote sensing (one article) …

Improved Methodologies In Modeling And Predicting Failure In Aashto M-180 Guardrail Steel Using Finite Element Analysis – Phase I, Brandt M. Humphrey, Robert W. Bielenberg, Ronald K. Faller, John D. Reid, Mehrdad Negahban

Nebraska Department of Transportation: Research Reports

No abstract provided.

Midwest Guardrail System (Mgs) Placed Adjacent To A 1v:2h Fill Slope With 6-Ft Posts, Austin J. Haase, Justine E. Kohtz, Karla A. Lechtenberg, John D. Reid, Ronald K. Faller

Nebraska Department of Transportation: Research Reports

No abstract provided.

Design Procedures Of Retrofitted Bridge Rail, Richard L. Wood, Yijun Liao, Mohammad E. Mohammadi, Jordan Wipf

Nebraska Department of Transportation: Research Reports

The use of shallow embedment anchors in concrete is essential for retrofit applications; however, the combination of steel anchors, chemical adhesive, and concrete acting as a single tensile mechanism creates uncertainties in anchor strength and failure modes. Differences in concrete compressive strengths and in specifications of adhesives between manufacturers increases uncertainty further. In addition to these issues, prior research conducted by others examines the behavior of such anchors with respect to cracked versus uncracked concrete, partial bonding of the embedded length, and strength reductions due to anchor proximity to edges. While it is understood, anchors require a proper installation detail, …

Identifying And Addressing Soil Property Issues Affecting Roadside Vegetation Establishment, Xu Li, Martha Mamo, Walter H. Schacht, Tala Awada, Humberto Blanco-Canqui

Nebraska Department of Transportation: Research Reports

Attaining adequate vegetation cover along highways is important for NDOR to comply with EPA’s stormwater regulations. However, low plant cover is a common problem on shoulders (first 16 feet off the pavement) of many highways in Nebraska. The ultimate goal of this study is to identify cost-effective engineering solutions that assure adequate seed beds (i.e., soil conditions) for establishment of selected seeding mixtures. The objectives of this study are to (1) characterize the soil properties along roadsides where vegetation stands have not developed well, and (2) verify the effects of select soil property parameters on plant germination and establishment.

Sampling …

Laboratory And Full Boom-Based Investigation Of Nozzle Setup And Restriction Effects On Flow, Pressure And Spray Pattern Distribution, Shane H. Forney

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

Pesticide application is an integral part of crop production and ground-based agricultural boom sprayers are used extensively to apply pesticides to the crop canopy or soil surface across millions of acres in the United States. Efficient application is necessary to minimize costs and limit adverse environmental impacts. Errors in flow rate and system pressure measurements may cause as-applied maps to incorrectly indicate application rates and could negatively affect downstream data processing or analysis. The goals of this study were to provide quantified measurements on the effects of nozzle setup errors on spray pattern uniformity and evaluate how laboratory patternator data …

Unmanned Aerial Vehicles For High-Throughput Phenotyping And Agronomic Research, Yeyin Shi, J. Alex Thomasson, Seth C. Murray, N. Ace Pugh, William L. Rooney, Sanaz Shafian, Nithya Rajan, Gregory Rouze, Cristine L. S. Morgan, Haly L. Neely, Aman Rana, Muthu V. Bagavathiannan, James Henrickson, Ezekiel Bowden, John Valasek, Jeff Olsenholler, Michael P. Bishop, Ryan Sheridan, Eric B. Putman, Sorin Popescu, Travis Burks, Dale Cope, Amir Ibrahim, Billy F. Mccutchen, David D. Baltensperger, Robert V. Avant, Jr., Misty Vidrine, Chenghai Yang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Advances in automation and data science have led agriculturists to seek real-time, high quality, high-volume crop data to accelerate crop improvement through breeding and to optimize agronomic practices. Breeders have recently gained massive data-collection capability in genome sequencing of plants. Faster phenotypic trait data collection and analysis relative to genetic data leads to faster and better selections in crop improvement. Furthermore, faster and higher-resolution crop data collection leads to greater capability for scientists and growers to improve precision-agriculture practices on increasingly larger farms; e.g., site-specific application of water and nutrients. Unmanned aerial vehicles (UAVs) have recently gained traction as agricultural …

Development And Assessment Of A Groundwater Sustainability Index In Climatically Diverse Groundwater Irrigated Regions In Nebraska, Maria A. Mulet Jalil

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

The aim of this research was to evaluate the impact of regional change in ET on groundwater level changes and the assessment and development of a groundwater sustainability index for climatically diverse regions across Nebraska during 2000-2014. Irrigation in the selected regions is predominantly supplied by groundwater. The hypothesis is that groundwater use can become sustainable if the regional evapotranspiration (ET) is managed so that it equals the ET of vegetation that is native to the region. Site locations were Box Butte, Chase, Dundy, Holt LNNRD and York Counties and 3 ecosystems were evaluated: native vegetation, dryland and irrigated cropping …

Use Of Recycled Crushed Concrete (Rcc) Fines For Potential Soil Stabilization, Lindeman Mark, Varilek Brandon, Lieska Halsey, Rick Gloe, Maria Olomi

Nebraska Department of Transportation: Research Reports

This study evaluated the use of Recycled Crushed Concrete (RCC) Fines for potential soil stabilization. Soil stabilization is the enhancement of subgrade stability to improve the constructability of successive pavement layers. Use of RCC fines may not only provide less costly alternatives for subgrade stabilization, but their use may also alleviate landfill disposal challenges.