Engineering Commons^™

Hydraulic And Mineralogical Characterization Of Organoclay Before And After Reaction With Non-Aqueous Phase Liquid (Napl), Mostafa Afzalian

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

Sediment capping—a method used to stabilize and remediate contaminated subaqueous sediment in lakes or river shores by covering the contaminant with multiple layered materials— is a more effective, economic, and durable in situ treatment compared to ex situ methods such as dredging. The caps are typically composed of porous geomaterials such as gravels, sands, Reactive Core Mat (RCM), including reactive soils (e.g., organoclay) and geosynthetics (e.g., geotextiles). The designed caps are regarded as water-permeable so as not to disturb the sediment; however, the caps become unsaturated state because of trapped gas generated from the decomposition of organic matter. Most of …

Concentration And Treatment Of Odors Generated By Landfills, Gabriel Cohen

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

Landfills produce hydrogen sulfide (H₂S), an odorous compound that can be a nuisance and danger to public. Biological treatment, in particular bio-trickling filters, is a method for controlling H₂S emissions but startup costs can be costly. The goal of this study is to provide a low-cost method for improving environmental air quality in Nebraska through an odor control device. This study determined that the Loup Central Landfill located near Elba, NE would be an adequate site for the testing and implementation of the odor control device. The off-gas of the Loup Central Landfill was tested for …

Risk Of Injury Analysis In Depth Jump And Squat Jump, Curtis L. Tomasevicz, Jeffrey C. Woldstad, David.Jones@Unl.Edu

Department of Biological Systems Engineering: Papers and Publications

Introduction: The depth jump (DJ) and squat jump (SJ) are accepted ways to assess and train power producing ability but are not without risk of injury. Methods: Sixteen male participants (age = 21.7 ± 1.54 yrs., height = 177.7 ± 11.4 cm, mass = 77.7 ± 13.6 kg) were evaluated for power exertion capabilities while being assessed for risk of injury in the knee and low back through a range of resistances based on a percentage of participants’ heights in the DJ (0% through 50%) and bodyweights for the SJ (0% through 100%). Two variables were used to assess the …

Comparative Analyses Of Variable And Fixed Rate Irrigation And Nitrogen Management For Maize In Different Soil Types: Part I. Impact On Soil-Water Dynamics And Crop Evapotranspiration, Vasudha Sharma, Suat Irmak

Department of Biological Systems Engineering: Papers and Publications

Understanding the soil-water dynamics and maize evapotranspiration (ETc) under variable rate irrigation (VRI) and variable rate fertigation (VRF) management with respect to soil spatial variability constitutes the basis for developing effective variable rate water and nitrogen management strategies. This long-term research was designed to quantify and compare the soil-water dynamics, including available water (AW), and ETc during vegetative and reproductive growth periods of VRI, fixed rate irrigation (FRI) and no-irrigation (NI) under fixed rate fertigation (FRF), VRF and pre-plant (PP) nitrogen management in three different soil types [Crete silt loam (S1); Hastings silty clay loam (S2) and Hastings silt loam …

Introduction To Special Issue Of Irrigation Science: Improving Irrigation Management Across The Ogallala Aquifer, Usa, Allan A. Andales, Daran Rudnick, José L. Chávez

Department of Biological Systems Engineering: Papers and Publications

Groundwater stored in aquifers is a major source of irrigation water for many agricultural regions that receive insufficient precipitation for crop production. In the U.S.A., the High Plains aquifer (HPA) that underlies parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming supplies irrigation water for agricultural production. The HPA underlies around 450,658 km² (174,000 mi²) of which the Ogallala aquifer is the principal geologic formation underlying 347,059 km² (134,000 mi²) (Gutentag et al. 1984). The Ogallala aquifer is primarily a water table (unconfined) aquifer with saturated thickness ranging from 0 …

Engaging Farmers And The Agriculture Industry Through The Testing Agricultural Performance Solutions Program, Charles A. Burr, Daran Rudnick, Matt Stockton, Robert Tigner, Krystle Rhoades

Department of Biological Systems Engineering: Papers and Publications

The University of Nebraska–Lincoln Testing Agricultural Performance Solutions (TAPS) program involves use of farm management competitions to increase engagement across producers, industry, and universities.Participants make several management decisions throughout the growing season in a controlled field trial held at the university research station. Results are analyzed, and awards are presented for most profitable farm, most efficient farm, and farm with the greatest grain yield. The TAPS program involves several techniques for facilitating participatory assistance, including two-way communication and transformational learning. It has resulted in participants' questioning their past management decisions and realizing that they need to improve their marketing skills …

Quantitative Assessment Of Alkali-Silica Reaction In Small And Large-Scale Concrete Specimens Utilizing Nonlinear Acoustic Techniques, Clayton Malone

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

Nonlinear resonance techniques have been shown to be sensitive to microcracking in materials, including alkali-silica reaction (ASR) damage in concrete. However, application of nonlinear resonance tests have been limited due to the difficulty of application to large-scale field structures and the inability to quantitatively relate material nonlinearity with damage development. In this study, the development of ASR in concrete prisms and large concrete beam specimens of varying aggregate types and specimen sizes was monitored using linear and nonlinear resonance techniques.

For the concrete prisms, although the linear resonance frequency test could detect initiation and development of ASR damage in specimens …

Climate Change And Market-Based Insurance Feedbacks, Eric R. Holley, Adam Liska, Cory Walters, Geoffrey C. Friesen, Michael Hayes, Max J. Rudolph, Donald A. Wilhite

Adam Liska Papers

Climatic events have accounted for 91% of $1.05 trillion in insured costs for global catastrophic events from 1980 to 2016. Costs are driven by socio-economic development and increased frequency and severity of climatic disasters driven by climate change. Government policies to reduce systemic risk (e.g., cap-and-trade, carbon tax) have been a predominant approach for mitigation and adaptation. Alternatively, market-based incentives for climate change adaptation and mitigation already operate via the insurance industry to lessen impacts on society. Insurance feedbacks include changes in 1) premiums and insurance policies, 2) non-coverage, and 3) policy making and litigation. Alongside government policies, insurance feedbacks …

Biofiltration Of Volatile Organic Compounds Emitted At Ethanol Plants, Mitham Al-Faliti

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

Ethanol is a major biofuel source of energy in the U.S. Ethanol production produces several harmful emissions from both fermentation tanks and dryers. CO₂ scrubbers control the emissions from the fermentation tanks, while the emissions from the dryers are controller by regenerative thermal oxidizers. These methods are expensive to operate. A potential alternative is bio-trickling filters. Bio-trickling filters are an inexpensive and environmentally friendly alternative. For this study, two parallel bio-trickling filters were operated one at 25°C called the mesophilic bio-trickling filter and one at 60°C called the thermophilic bio-trickling filter. The mesophilic bio-trickling filter simulates emissions from fermentation …

Comparison Of Object Detection And Patch-Based Classification Deep Learning Models On Mid- To Late-Seasonweed Detection In Uav Imagery, Arun Narenthiran Veeranampalayam Sivakumar, Jiating Li, Stephen Scott, Eric T. Psota, Amit J. Jhala, Joe D. Luck, Jiating Li

Department of Biological Systems Engineering: Papers and Publications

Mid- to late-season weeds that escape from the routine early-season weed management threaten agricultural production by creating a large number of seeds for several future growing seasons. Rapid and accurate detection of weed patches in field is the first step of site-specific weed management. In this study, object detection-based convolutional neural network models were trained and evaluated over low-altitude unmanned aerial vehicle (UAV) imagery for mid- to late-season weed detection in soybean fields. The performance of two object detection models, Faster RCNN and the Single Shot Detector (SSD), were evaluated and compared in terms of weed detection performance using mean …

Development Of A Mash Test Level 4 Open Concrete Bridge Rail, Jacob Delone

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

An open concrete bridge rail was designed and developed according to safety performance guidelines in the American Association of State Highway Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) for Test Level 4 (TL-4). Systems designed and developed under previous guidance were studied, and their geometric information and full-scale crash testing performance was studied to establish the geometry of the new bridge rail. Yield-Line Theory and the AASHTO Post and Beam design methods were studied, and a modified version of the AASHTO Post and Beam method was utilized to determine the capacity of the new open concrete bridge rail. …

Development Of An Improved Arterial Roadway Performance Reliability Methodology, Ernest Tufuor

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

The need for reliable performance measures of urban arterial roadways is increasing because of the rise in traffic congestion and the high value of travel time. Consequently, travel time reliability (TTR), which combines components of measures of central tendency and measures of dispersion of travel times, has recently received considerable research interest.

The basis of all TTR metrics is the travel time distribution (TTD). Estimating and forecasting arterial TTDs for TTR analysis is the focus of this dissertation. This dissertation proposes a new TTR methodology that is a marked improvement on recent TTR estimation and forecasting methodologies including the current …

Optimum Mixing Design Of Xanthan And Gellan Treated Soils For Slope Stabilization For Weathered Shales And Glacial Tills In Nebraska, Layal Bitar

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

Verdigre located in North Eastern Nebraska experienced slope failures. The geological formations of theses slopes largely consist of several layers of weathered shales and glacial tills. It is believed that the weathering process reduced the shear strength of the soils leading to slope failures.

In this study, strength characteristics of Xanthan and Gellan gums treated soil specimens compacted at the optimum moisture content for field application were investigated so that the biopolymer treated soils may be properly used to stabilize the slopes. The untreated and treated samples were subjected to a wet-freeze(-6^oF)-thaw(167^oF)-dry weathering process up to …

Past, Present And Future Of Irrigation On The U.S. Great Plains, Steve R. Evett, Paul D. Colaizzi, Freddie R. Lamm, Susan A. O'Shaughnessy, Derek M. Heeren, Thomas J. Trout, William L. Kranz, Xiaomao Lin

Department of Biological Systems Engineering: Papers and Publications

Motivated by the need for sustainable water management and technology for next-generation crop production, the future of irrigation on the U.S. Great Plains was examined through the lenses of past changes in water supply, historical changes in irrigated area, and innovations in irrigation technology, management, and agronomy. We analyzed the history of irrigated agriculture through the 1900s to the present day. We focused particularly on the efficiency and water productivity of irrigation systems (application efficiency, crop water productivity, and irrigation water use productivity) as a connection between water resource management and agricultural production. Technology innovations have greatly increased the efficiency …

Retention Of Swine Slurry Constituents In Soil And Crop Residue As Affected By Setback Distance, John E. Gilley, Shannon L. Bartelt-Hunt, Kent M. Eskridge, Xu Li, Amy M. Schmidt, Daniel D. Snow

Department of Biological Systems Engineering: Papers and Publications

Setbacks are prescribed distances from surface waters within which manure application is not allowed. Little information is available concerning the retention of swine slurry constituents in soil and crop residue materials within setback areas. This study was conducted to measure the retention of selected constituents within a setback area following the upslope application of swine slurry and the introduction of simulated rainfall. The no-till cropland site had a slope gradient of 4.9% and a mean winter wheat residue cover of 7.73 Mg ha−1 . Soil and vegetative samples were collected on 3.7 m wide by 23.2 m long plots with …

Economic Comparisons Of Variable Rate Irrigation And Fertigation With Fixed (Uniform) Rate Irrigation And Fertigation And Pre-Plant Fertilizer Management For Maize In Three Soils, Vasudha Sharma, Suat Irmak

Department of Biological Systems Engineering: Papers and Publications

Extensive field research for data collection to conduct economic comparisons of variable rate irrigation (VRI) with fixed (uniform) rate irrigation (FRI) and no irrigation (NI) in combination with three nitrogen application strategies of fixed (uniform) rate fertigation (FRF), variable rate fertigation (VRF) and pre-plant nitrogen (PP) management for maize (Zea mays L.) were conducted. Research was conducted in three soil types [(i) Crete silt loam (S1); (ii) Hastings silty clay loam (S2); and (iii) Hastings silt loam (S3)] for three growing seasons (2015, 2016 and 2017) in Nebraska, USA. For the economic analyses, the average initial investment of the …

Riveted Steel Railway Bridge Health Monitoring And Damage Detection, Ahmed Rageh

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

Visual inspection is often used to assess the condition of railway bridges at discrete points in time, an approach that can be subjective and possibly unsafe. Alternatively, certain bridges have their condition assessed via the installation of a large number of sensors. These sensors can be costly to place, power and maintain. Therefore, reducing their numbers and maximizing the extracted information is of utmost importance. In addition, evaluating bridge condition from measured response can be quite challenging due to loading and environmental variations, especially when a limited number of sensors are used.

The focus of this research is to develop …

Extracellular Matrix Disparities In An Nkx2-5 Mutant Mouse Model Of Congenital Heart Disease, Deanna Bousalis, Christopher S. Lacko, Nora Hlavac, Fariz Alkassis, Rebecca A. Wachs, Sahba Mobini, Christine E. Schmidt, Hideko Kasahara

Department of Biological Systems Engineering: Papers and Publications

Congenital heart disease (CHD) affects almost one percent of all live births. Despite diagnostic and surgical reparative advances, the causes and mechanisms of CHD are still primarily unknown. The extracellular matrix plays a large role in cell communication, function, and differentiation, and therefore likely plays a role in disease development and pathophysiology. Cell adhesion and gap junction proteins, such as integrins and connexins, are also essential to cellular communication and behavior, and could interact directly (integrins) or indirectly (connexins) with the extracellular matrix. In this work, we explore disparities in the expression and spatial patterning of extracellular matrix, adhesion, and …

Development Of An In Vitro Intervertebral Disc Innervation Model To Screen Neuroinhibitory Biomaterials, Sarah M. Romereim, Caleb A. Johnston, Adan L. Redwine,, Rebecca A. Wachs

Department of Biological Systems Engineering: Papers and Publications

Pain originating from an intervertebral disc (discogenic pain) is a major source of chronic low back pain. Pathological innervation of the disc by pain‐sensing nerve fibers is thought to be a key component of discogenic pain, so treatment with biomaterials that have the ability to inhibit neurite growth will greatly benefit novel disc therapeutics. Currently, disc therapeutic biomaterials are rarely screened for their ability to modulate nerve growth, mainly due to a lack of models to screen neuromodulation. To address this deficit, our lab has engineered a three dimensional in vitro disc innervation model that mimics the interface between primary …

Reliability-Calibrated Ann-Based Load And Resistance Factor Load Rating For Steel Girder Bridges, Francisco Garcia

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

This research aimed to develop a supplemental ANN-based tool to support the Nebraska Department of Transportation (NDOT) in optimizing bridge management investments when choosing between refined modeling, field testing, retrofitting, or bridge replacement. ANNs require an initial investment to collect data and train a network, but offer future benefits of speed and accessibility to engineers utilizing the trained ANN in the future. As the population of rural bridges in the Midwest approaching the end of their design service lives increases, Departments of Transportation are under mounting pressure to balance safety of the traveling public with fiscal constraints. While it is …

Evaluation Of Low-Cost Depth Cameras For Agricultural Applications, Isabella C.F.S. Condotta, Tami M. Brown-Bandl, Santosh Pitla, John P. Stinn, Késia O. Silva-Miranda

Department of Biological Systems Engineering: Papers and Publications

Low-cost depth-cameras have been used in many agricultural applications with reported advantages of low cost, reliability and speed of measurement. However, some problems were also reported and seem to be technology related, so understanding the limitations of each type of depth camera technology could provide a basis for technology selection and the development of research involving its use. The cameras use one or a combination of two of the three available technologies: structured light, time-of-flight (ToF), and stereoscopy. The objectives were to evaluate these different technologies for depth sensing, including measuring accuracy and repeatability of distance data and measurements at …

Biological Systems Engineering, Asmaa Abdella, Fernando Segato, Mark R. Wilkins

Department of Biological Systems Engineering: Papers and Publications

The present work studied the optimization of aeration rate, agitation rate and oxygen transfer and the use of various batch fermentation strategies for xylanase production from a recombinant Aspergillus nidulans strain in a 3 L stirred tank reactor. Maximum xylanase production of 1250 U/mL with productivity of 313 U/mL/day was obtained under an aeration rate of 2 vvm and an agitation rate of 400 rpm using batch fermentation. The optimum volumetric oxygen transfer coefficient (kLa) for efficient xylanase production was found to be 38.6 h1. Fed batch mode and repeated batch fermentation was also performed with kLa was 38.6 h1. …

Eliminating Rebar Splicing In Transverse Joints Of Precast Full Depth Bridge Deck Panels, David Gee

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

This study looks at the removal of longitudinal rebar splicing when sufficient longitudinal post-tensioning is provided for full-depth precast deck panels for simply supported bridges. Full-depth precast prestressed concrete deck panels are high quality plant produced pretensioned panels. They are often post-tensioned at the site to provide an average net compression in the joint of at least 250 psi due to effective prestress. This is to ensure adequate transfer of load as truck wheels pass over the joint. This net compression on the transverse joint is not explicitly clear by the AASHTO LRFD Bridge Design Specifications. Based on this section, …

Capturing Spatial Variability In Maize And Soybean Using Stationary Sensor Nodes, Jasreman Singh, Derek M. Heeren, Yufeng Ge, Geng Bai

Department of Biological Systems Engineering: Papers and Publications

• Irrigation in agriculture maximizes crop yield and improves food security globally • Irrigation scheduling is strongly based on the ability to accurately estimate the appropriate amount and timing of water application • The timing of the irrigation can best be informed through the crop canopy stress, and the amount of irrigation is informed through soil moisture depletion

• Developing upper (non-water stressed) and lower (non-transpiring) baselines for irrigated and non-irrigated maize and soybean • Investigating the relationship between the canopy stress and the soil moisture stress

The canopy temperature stress and soil moisture depletion had stronger correlation for non-irrigated …

Evidence Of Arithmetical Uncertainty In Estimation Of Light And Water Use Efficiency, Meetpal S. Kukal, Suat Irmak Dr.

Department of Biological Systems Engineering: Papers and Publications

It was demonstrated that conventional resource use efficiency (RUE) estimation methodology is largely subject to arithmetic weakness. Extensive field research data on aboveground biomass (AGB), absorbed photosynthetically active radiation (APAR), and crop evapotranspiration (ETc) in maize, soybean, sorghum, and winter wheat confirmed this methodological bias for light use efficiency (LUE) and water use efficiency (WUE) estimation. LUE and WUE were derived using cumulated (data aggregates across samplings) and independent (data increments across samplings) approaches. Use of cumulated data yielded strong-but-false correlation between AGB and APAR or Etc, being a statistical artefact. RUE values from an independent (data increments across samplings) …

Predicting Escherichia Coli Loads In Cascading Dams With Machine Learning: An Integration Of Hydrometeorology, Animal Density And Grazing Pattern, Olufemi P. Abimbola, Aaron R. Mittelstet, Tiffany Messer, Elaine D. Berry, Shannon L. Bartelt-Hunt, Samuel Hansen

Department of Biological Systems Engineering: Papers and Publications

Accurate prediction of Escherichia coli contamination in surface waters is challenging due to considerable uncertainty in the physical, chemical and biological variables that control E. coli occurrence and sources in surface waters. This study proposes a novel approach by integrating hydro-climatic variables as well as animal density and grazing pattern in the feature selection modeling phase to increase E. coli prediction accuracy for two cascading dams at the USMeat Animal Research Center (USMARC), Nebraska. Predictive models were developed using regression techniques and an artificial neural network (ANN). Two adaptive neuro-fuzzy inference system (ANFIS) structures including subtractive clustering and fuzzy c-means …

Banning Carbon Nanotubes Would Be Scientifically Unjustified And Damaging To Innovation, Daniel A. Heller, Prakrit V. Jena, Matteo Pasquali, Kostas Kostarelos, Lucia G. Delogu, Rachel E. Meidl, Slava V. Rotkin, David A. Scheinberg, Robert E. Schwartz, Mauricio Terrones, Yu Huang Wang, Alberto Bianco, Ardemis A. Boghossian, Sofie Cambré, Laurent Cognet, Simon R. Corrie, Philip Demokritou, Silvia Giordani, Tobias Hertel, Tetyana Ignatova, Mohammad F. Islam, Nicole M. Iverson, Anand Jagota, Dawid Janas, Junichiro Kono, Sebastian Kruss, Markita P. Landry, Yan Li, Richard Martel, Shigeo Maruyama, Anton V. Naumov, Maurizio Prato, Susan J. Quinn, Daniel Roxbury, Michael S. Strano, James M. Tour, R. Bruce Weisman, Wim Wenseleers, Masako Yudasaka

Department of Biological Systems Engineering: Papers and Publications

In a recent correspondence, the Swedish non-profit organization ChemSec announced the addition of carbon nanotubes to the SIN (‘Substitute It Now’) list1. Carbon nanotubes were added as an entire material class that “should be restricted or banned in the EU.” We believe that this recommendation confuses researchers and the public as it is based on evidence from a very narrow subset of data. Such a designation will likely hinder innovations that could lead to safe and effective applications of carbon nanotubes. Furthermore, this line of reasoning could damage other fields of science and technology, if applied similarly. We have worked …

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.

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 …

An Automated Seepage Meter For Streams And Lakes, D. Kip Solomon, Eric Humphrey, Troy E. Gilmore, David P. Genereux, Vitaly Zlotnik

Department of Biological Systems Engineering: Papers and Publications

We describe a new automatic seepage meter for use in soft bottom streams and lakes. The meter utilizes a thin‐walled tube that is inserted into the streambed or lakebed. A hole in the side of the tube is fitted with an electric valve. Prior to the test, the valve is open and the water level inside the tube is the same as the water level outside the tube. The test starts with closure of the valve, and the water level inside the tube changes as it moves toward the equilibrium hydraulic head that exists at the bottom of the tube. …