Civil and Environmental Engineering Commons^™

Representing Organic Matter Thermodynamics In Biogeochemical Reations Via Substrate-Explicit Modeling, Hyun-Seob Song, James C. Stegen, Emily B. Graham, Joon-Yong Lee, Vanessa A. Garayburu-Caruso, William C. Nelson, Xingyuan Chen, J. David Moulton, Timothy D. Scheibe

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Predictive biogeochemical modeling requires data-model integration that enables explicit representation of the sophisticated roles of microbial processes that transform substrates. Data from high-resolution organic matter (OM) characterization are increasingly available and can serve as a critical resource for this purpose, but their incorporation into biogeochemical models is often prohibited due to an over-simplified description of reaction networks. To fill this gap, we proposed a new concept of biogeochemical modeling—termed substrate-explicit modeling—that enables parameterizing OM-specific oxidative degradation pathways and reaction rates based on the thermodynamic properties of OM pools. Based on previous developments in the literature, we characterized the resulting kinetic …

Within-Field Variability In Granular Matrix Sensor Data And Its Implications For Irrigation Scheduling, T. Lo, H.C. Pringle Iii, Daran Rudnick, Geng Bai, L. Jason Krutz, D.M. Gholson, Xin Qiao

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Even when located within the same field, multiple units of the same soil moisture sensor rarely report identical values. Such within-field variability in soil moisture sensor data is caused by natural and manmade spatial heterogeneity and by inconsistencies in sensor construction and installation. To better describe this variability, daily soil water tension values from 14-23 sets of granular matrix sensors during the middle part of four soybean site-years in the Mississippi Delta were analyzed. The soil water tension data were found to follow approximately normal distributions, to exhibit moderately high temporal rank stability, and to show strong positive correlation between …

Teacher Level Factors And Student Achievement In A Cyber-Enabled Engineering Education Professional Development Program, Wei Zakharov, Johannes Strobel, Heidi A. Diefes-Dux

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study investigates the impact of an elementary engineering education teacher professional development program on student learning. The results show a significant increase in students’ knowledge in science from pre- to post-test as well as in engineering design from grade two to grade four. Further, the study uses multilevel modeling to quantitatively analyze the impact of differences among teachers on the engineering design achievement of their students. Different predictive relationships between demographic and social capital factors at the teacher level and student achievement are identified and implications for educational policymaking and practices are discussed.

Predicting Total Petroleum Hydrocarbons In Field Soils With Vis–Nir Models Developed On Laboratory-Constructed Samples, Nuwan K. Wijewardane, Yufeng Ge, Natasha Sihota, Thomas Hoelen, Toni Miaso, David C. Weindorf

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Accurate quantification of petroleum hydrocarbons (PHCs) is required for optimizing remedial efforts at oil spill sites. While evaluating total petroleum hydrocarbons (TPH) in soils is often conducted using costly and time-consuming laboratory methods, visible and near-infrared reflectance spectroscopy (Vis–NIR) has been proven to be a rapid and cost-effective field-based method for soil TPH quantification. This study investigated whether Vis–NIR models calibrated from laboratory-constructed PHC soil samples could be used to accurately estimate TPH concentration of field samples. To evaluate this, a laboratory sample set was constructed by mixing crude oil with uncontaminated soil samples, and two field sample sets (F …

Antibiotic Resistance Gene Profile Changes In Cropland Soil After Manure Application And Rainfall, Morgan A. Meyers, Lisa M. Durso, John E. Gilley, Heidi Waldrip, Lana Castleberry, Amy Schmidt

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Land application of manure introduces gastrointestinal microbes into the environ- ment, including bacteria carrying antibiotic resistance genes (ARGs). Measuring soil ARGs is important for active stewardship efforts to minimize gene flow from agri- cultural production systems; however, the variety of sampling protocols and target genes makes it difficult to compare ARG results between studies. We used polymerase chain reaction (PCR) methods to characterize and/or quantify 27 ARG targets in soils from 20 replicate, long-term no-till plots, before and after swine manure application and simulated rainfall and runoff. All samples were negative for the 10 b-lactamase genes assayed. For tetracycline resistance, …

Setback Distance Impacts On Transport And Antibiotic Resistance Phenotypes Of Fecal Indicators, Morgan A. Meyers, Lisa M. Durso, John E. Gilley, Daniel N. Miller, Xu Li, Amy M. Schmidt Schmidt

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Although the land application of livestock manure has numerous agronomic benefits, runoff from manured fields can degrade water quality. Setbacks instruct a minimum distance be maintained between manure application and surface waters. They are commonly used to manage nutrient contamination of surface waters; however, their utility for reducing microbial inputs remains unclear. Here we evaluated the efficacy of five setback distances in no-till wheat (Triticum aes- tivum L.) residue plots for reducing runoff fecal indicator concentrations from swine manure-amended fields. Also, since there is increasing interest in the use of water quality indicators to monitor antibiotic resistance in environmental sys- …

Innovative Extension Methods In The U.S. To Promote Irrigation Water Management, Daran Rudnick, Matt Stockton, Saleh Taghvaeian, Jason Warren, Michael D. Dukes, Amy Kremen, Christopher G. Henry, Jonathan Aguilar, Brenda Ortiz, Allan A. Andales, Chuck A. Burr, Xin Qiao, Wei‑Zhen Liang, Steven Walthour, Steve H. Amosson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Promotion and adoption of irrigation water management (IWM) technology, tools, and best management practices are important as water availability concerns are addressed. Traditional extension programs have relied on lecture presentations, field tours, fact sheets, and on-station demonstrations to promote IWM practices and tools. However, these platforms tend not to provide the experience and opportunity for growers to identify and become comfortable with innovative solutions, such as new technology. To address these challenges and to appeal to an ever-changing client base, innovative and locally relevant extension and outreach programs have been devised to engage and educate growers. This article describes some …

Accumulation And Release Of Nutrients By Immersed Stalks Collected On Selected Dates Following Harvest, John E. Gilley, David B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The concentrations of phosphorus (P) and nitrogen (N) in runoff from cropland areas may be influenced by accumulation and release of P and N by stalk residues. A laboratory study was conducted to measure the effects of time since harvest and immersion period on accumulation and release of P and N by corn, soybean, and wheat stalks. Experimental variables included type of stalk material (corn, soybean, and wheat), time since harvest (six residue collection dates over an approximate 1-year period), and stalk immersion period (25 s (0.42 min), 250 s (4.2 min), 2500 s (42 min), 25,000 s (6.9 h), …

Effect Of Urea Fertilizer Deep Placement Days After Transplanting Using Brri Prilled Urea Applicator On Transplanted Boro Rice Yield, Muhammad Rashed Al Mamun, K. Naher, Md Towfiqur Rahman, Md Anwar Hossen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Rice is the most important crop in the developing countries of Asia. In the south and south-east Asia, rain-fed and irrigated transplanted rice occupies nearly two-thirds of the rice-growing area and produces more than 80% of the rough rice. In these areas, prilled urea conventionally applied by farmers is very insufficient in the transplanted rice field, where severe losses occur (up to 60% of applied N) via NH₃volatilization, denitrification, leaching, and runoff. Considering loss minimization, an experiment was conducted during the Boro season at Bangladesh Agricultural Development Corporation (BADC) in Sylhet to evaluate the performance of BRRI Prilled …

Effect Of Rotary Blade Modification On Residue Retention Into Conservation Agriculture Practices, Md Talash Mahmud, Md Towfiqur Rahman, Md Mosharraf Hossain, Muhammad Ashik-E-Rabbani

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Conservation Agriculture (CA) has been a promising technique for better crop production. Manual seeding with conventional tillage practice is laborious and time consuming. However, Strip tillage (ST) method incorporating seeding machines minimizes human drudgery and optimizes the crop yield. Many problems associated with ST have been rectified e.g. tiny furrow backfill, inaccuracy of seed and fertilizer placement, leading to poor germination and curtailed outcomes. This article focused on the effects of residue retention for the rotary blades design on a versatile multi-crop planter (VMP). Four types of rotary blades of VMP differed by 15^o increment of tip angles were …

Regional Sustainable Development Of Renewable Natural Resources Using Net Primary Productivity On A Global Scale, Saket Dubey, Ashutosh Sharma, Venkatesh Kishor Panchariya, Manish Kumar Goyal, Rao Y. Surampalli, Tian C. Zhang

Department of Civil and Environmental Engineering: Faculty Publications

Ecological Indicators 127 (2021) 107768

The Fluxnet2015 Dataset And The Oneflux Processing Pipeline For Eddy Covariance Data, Gilberto Pastorello, Timothy Arkebauer, Dave P. Billesbach, Anatoly Gitelson, Adam Liska, Andrew Suyker, Elizabeth Walter-Shea, More Than 200 Other

Adam Liska Papers

The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as …

Wastewater Treatment Fatty Acids For Biodiesel Production, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Wastewater scum is the thick oily substance that floats on top of the primary and secondary tanks within a wastewater treatment plant. Scum has a 30% to 60% lipid content making it an excellent resource for the biodiesel industry. Also the use of scum would reduce the cost of current management practices such as landfill disposal or incineration. In this article there is an overview of lipid byproducts currently being produced at wastewater treatment plants today. This is followed by a presentation showing a full length process for turning wastewater scum into biodiesel raw material.

Remediating Soil For Successful Vegetation Establishment Along Nebraska Highways, Shad Mills, Martha Mamo, Walt Schacht, Humberto Blanco-Canqui

Nebraska Department of Transportation: Research Reports

Vegetation along roadsides is important to prevent soil erosion, provide habitat, and filter water running off the road. Vegetation close to the pavement along highways in Nebraska does not readily establish and persist. It is thought that the sodium and bulk density are the driving factors behind the lack of vegetation. After a construction project the shoulder is seeded into the compacted soil, and during winter salts can accumulate in the soil because of deicing agents being used. The purpose of our study was to determine if the sodium and bulk density are the driving factors of the vegetation cover. …

Establishment Of Wildflower Islands To Enhance Roadside Health And Aesthetics, Walter Schacht, Judy Wu-Smart

Nebraska Department of Transportation: Research Reports

Wildflowers are crucial in the ecological function of the low-input roadside plant communities in terms of water andnutrient cycling, nutrient inputs such as nitrogen, total plant canopy cover, stand longevity, and provision of habitat for numerous small animals. Further, wildflowers provide critical foraging and nesting resources for birds, insects, and other wildlife. Unfortunately, habitat loss from agricultural and urban development has led to rapid population declines in wild bees and other pollinators across the US, thereby jeopardizing not only food production but also the sustainability of our natural landscapes (Kearns & Inouye, 1997). One way to mitigate wild bee decline …

Protocol Efficiently Measuring The Swelling Rate Of Hydrogels, Katherine Zhang, Wuxiang Feng, Congrui Jin

Department of Civil and Environmental Engineering: Faculty Publications

Hydrogels are polymeric materials which can swell in water and retain a significant fraction of water within their structure without dissolving in water. Swelling rate is one of the most important properties of hydrogels. To measure the swelling rate, the profile of swelling capacity versus time of a hydrogel sample is obtained by performing free-absorbency capacity measurements at consecutive time intervals. Traditionally, either the tea-bag method, the sieve method, or the filtration method is used for the free-absorbency capacity measurements depending on the amount of the available sample and the desired precision. However, each method has its own systematic drawbacks. …

Lidar Assessment To Monitor Bridge Response Under Live And Dead Loads, Daniel Watson

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

Understanding how a bridge structure responds to various loads in a time and resource-efficient approach is vital in characterizing bridge health. Bridge health monitoring is an evaluation of the structural condition and performance, which optimizes limited transportation budgets by prioritizing the bridges that are in the most need for retrofit or replacement. Identifying and remedying issues will mitigate long-term problems and ensure that the bridge remains open to service for all legal loads. In contrast, health monitoring and load rating will determine if a bridge can only carry traffic up to a certain weight or speed, requiring a bridge load …

Multiscale Modeling Of Fracture In Quasi-Brittle Materials Using Bifurcation Analysis And Element Elimination Method, Keyvan Zare Rami

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

Analyzing the fracture of heterogeneous materials is a complex problem, due to the fact that the mechanical behavior of a heterogeneous material is strongly dependent on a variety of factors, such as its microstructure, the properties of each constituent, and interactions between them. Therefore, these factors must be effectively taken into account for accurate analysis, for which the multiscale method has been widely used. In this scheme, the computational homogenization method is used to obtain the effective macroscopic properties of a heterogeneous material based on the response of a Representative Volume Element (RVE). The growth of damage in an RVE …

Small Ruminant Health Intervention Calendar In Ethiopia, Mesfin Mekonnen, Ayalew Assefa, Tesfalem Nane, Firdawok Ayele, Asrat Arke, Belay Elias, Barbara Wieland

Daugherty Water for Food Global Institute: Faculty Publications

Contents

1 Background................................................................................................... 3
2 Developing the health intervention calendar............................................................ 4
The treatment calendar ......................................................... 4 Applying the calendar..................................................................... 5 4 References................................................................... 8

Environmental Sustainability Assessment Of Small Nebraska Mechanical Water Resource Recovery Facilities: Impacts Of Construction And Operations, Sussan Moussavi

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

Many small, rural communities struggle with aging or inadequate water resource recovery facilities (WRRFs), and face challenges in constructing and operating such systems. Although existing literature has provided insight into the environmental sustainability of large systems including both the construction and operational phases, these studies have not examined small systems in adequate depth or breadth. The environmental impacts associated with construction may be notable for small WRRFs since the initial construction can be a larger share of the total life cycle environmental impact.

The goal of this work is to provide the environmental sustainability profiles of 12 mechanical WRRFs in …

Evaluation Of Reducing Cement Content In Ndor Class R Combined Aggregate Gradations, Miras Mamirov, Jiong Hu, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

The main objective of this research project was to achieve a cement reduction on Nebraska slip-form pavement concrete through aggregate particle packing optimization. A literature review was conducted to examine different aggregate optimization tools, quality control tests, and historical data of Nebraska Department of Transportation (NDOT) pavement mixtures. It was found that the Modified Toufar Model has good potential in optimizing particle packing and predicting packing degrees. The combined aggregate void content test was found to be useful to experimentally justify optimized aggregate gradations. The Box Test with a modified index and image analysis tool for surface void estimation was …

Long-Term Performance Evaluation Of Nudeck In Kearney East Bypass, George Morcous, Marc Maguire

Nebraska Department of Transportation: Research Reports

The Kearney East Bypass bridge is the first project that implements the newly developed precast concrete deck system (known as 2nd generation NUDECK). The new system consists of full-depth full-width precast prestressed concrete deck panels that are 12 ft (3.66 m) long each. The panels have covered shear pockets at 4 ft (1.22 m) spacing on each girder line to host clustered shear connectors that are adjustable in height. Narrow unreinforced transverse joints are used to eliminate the need for deck overlay. Also, deck panels are post-tensioned in the longitudinal direction using a new post-tensioning system that eliminates the need …

Standard Design For Nebraska County Bridges, Chungwook Sim, Jiong Hu, Maher K. Tadros, Alexander Bleyhl, David Gee

Nebraska Department of Transportation: Research Reports

Many county-owned bridges in Nebraska need replacement due to their structural deficiency. Most of the bridges needing replacement are in the 40 to 60 ft range. This span range lacks a standard design that fits Nebraska county practices in terms of speed and simplicity of construction. The current systems being used are (a) Precast 1 by 2 ft planks which can span up to 30 ft, (b) Cast-in-place slab bridges which can span up to 50 ft but require extensive field formwork, concrete placing, and curing, and are best when constructed in three-span units, and (c) Inverted tees which can …

Precast Concrete Deck-To-Girder Connection Using Uhpc, George Morcous, Mostafa Abo El-Khier

Nebraska Department of Transportation: Research Reports

The implementation of ultra-high-performance concrete (UHPC) in bridge construction has been growing rapidly in the last two decades due to its excellent mechanical properties, workability, and durability. This report presents a new UHPC connection between precast concrete deck panels and bridge girders that eliminates changes to the design and production of girder shear connectors commonly used in conventional cast-in-place concrete deck construction. In conventional construction, girder shear reinforcement or studs are extended into the cast-in-place concrete deck to transfer interface shear and create composite section. In the new connection, girder shear reinforcement or studs are kept underneath the deck panels, …

Development Of High-Performance Rapid Patching Materials For Pavement Repair, Gholami Shayan, Jiong Hu, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

Concrete pavements exhibiting severe distresses which require patching are commonly observed in the concrete pavement in Nebraska. Due to the requirements of opening pavement to traffic after placing the rapid patching materials, it is essential for that concrete to achieve high early strength. To ensure this, a high cement content and chloride-based accelerators are currently used in the Nebraska Department of Transportation (NDOT) Portland cement-based rapid-patching materials. Besides its associated high cost, high cement content tends to result in a less stable mix with high shrinkage, high heat of hydration, and high cracking potential. In addition, using chloride-based accelerators has …

Condition Assessment Of Bridge Decks With Asphalt Overlay, Sepehr Pashoutani, Jinying Zhu

Nebraska Department of Transportation: Research Reports

Ground penetrating RADAR (GPR) is a widely used nondestructive testing (NDT) method for bridge deck evaluation. However, the current GPR signal and data processing software and algorithms are not able to provide comprehensive information about bridge deck condition. Although the original objective of this research project was to develop GPR analysis algorithms for condition assessment of bridge decks with asphalt overlay, the scope of work has been expanded to concrete bridge decks with or without overlays.

In this study, the research team developed a complete GPR analysis procedure that includes the following components: 1) obtain zero-time for GPR reflection at …

Development Of A Mix Design Adjustment Method For Fiber Reinforced Concrete And Super High Performance Concrete Based On Excess Paste, Joe Malloy

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

The main objective of this study was to develop a mix design adjustment method for Fiber Reinforced Concrete (FRC) that would maintain appropriate workability while improving hardened concrete performance. A literature review was conducted to examine existing methods for adjusting mix designs to account for fiber introduction. It was found that while increasing fine aggregate and cement paste content can make up for lost workability with the addition of fibers, no rational mix design adjustment method is available. Reference mix designs from the Nevada Department of Transportation and the Nebraska Department of Transportation were used, and this study focused on …

The Application Of Gray-Scale Level-Set Method In Segmentation Of Concrete Deck Delamination Using Infrared Images, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Conventional nondestructive delamination detection of concrete pavements through thermography is often based on temperature contrasts between delaminated and sound areas. Non-uniform backgrounds caused by the environmental conditions are often challenging for contrast-based methods to robustly differentiate the delaminated areas from the sound areas. Instead of focusing on the temperature contrast, this study proposes a temperature gradient-based level set method (LSM) to detect boundaries for delamination segmentations. A modified edge indicator function is developed to represent the normalized temperature gradient of a thermal image. The experimental study was conducted to evaluate its applicability and stability for boundary detection in terms of …

A Co-Optimal Coverage Path Planning Method For Aerial Scanning Of Complex Structures, Zhexiong Shang, Justin Bradley, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

The utilization of unmanned aerial vehicles (UAVs) in survey and inspection of civil infrastructure has been growing rapidly. However, computationally efficient solvers that find optimal flight paths while ensuring high-quality data acquisition of the complete 3D structure remains a difficult problem. Existing solvers typically prioritize efficient flight paths, or coverage, or reducing computational complexity of the algorithm – but these objectives are not co-optimized holistically. In this work we introduce a co-optimal coverage path planning (CCPP) method that simultaneously co-optimizes the UAV path, the quality of the captured images, and reducing computational complexity of the solver all while adhering to …

Evaluation Of Internally Cured Bridge Deck Concrete With Standard And Optimized Aggregate Gradation, Arman Abdigaliyev

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

Due to the relatively high cement content and low water-to-cement ratio (w/c) used, bridge deck concrete is prone to premature cracking. Internal curing has been found to greatly reduce the chance of premature cracking as well as concrete deterioration. This research developed internally cured bridge deck concrete based on a local mix design in Nebraska. Four different lightweight fine aggregate (LWFA) as internal curing agents were evaluated and their effects on fresh, mechanical, durability, and shrinkage properties of concrete were studied. The study focused on resolving two issues associated with fine aggregate replacement based on Bentz equation. To identify the …