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Full-Text Articles in Engineering

Single-Pass Inline Pipeline 3d Reconstruction Using Depth Camera Array, Zhexiong Shang, Zhigang Shen Jun 2022

Single-Pass Inline Pipeline 3d Reconstruction Using Depth Camera Array, Zhexiong Shang, Zhigang Shen

Faculty Publications in Construction Engineering & Management

A novel inline inspection (ILI) approach using depth cameras array (DCA) is introduced to create high-fidelity, dense 3D pipeline models. A new camera calibration method is introduced to register the color and the depth information of the cameras into a unified pipe model. By incorporating the calibration outcomes into a robust camera motion estimation approach, dense and complete 3D pipe surface reconstruction is achieved by using only the inline image data collected by a self-powered ILI rover in a single pass through a straight pipeline. The outcomes of the laboratory experiments demonstrate one-millimeter geometrical accuracy and 0.1-pixel photometric accuracy ...


Design Of Path Correction For Improved Gait Rehabilitation, Zvonimir Pusnik May 2022

Design Of Path Correction For Improved Gait Rehabilitation, Zvonimir Pusnik

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Following a serious neurological injury or disease, such as a spinal cord injury or multiple sclerosis, many patients develop impaired gait (the ability to walk). There are many different pieces of equipment to help rehabilitate people with impaired gait, ranging from over ground walking with exoskeletons to treadmills with partial bodyweight support. Since the 1990s and 2000s, elliptical trainers have entered the rehabilitative field as a machine with low impact forces and gait-like motion. This led researchers at Madonna Rehabilitation Hospitals to collaborate with the University of Nebraska-Lincoln to create the Intelligently Controlled Assistive Rehabilitation Elliptical (ICARE).

While the ICARE ...


Development Of A Next-Generation Non-Proprietary Portable Concrete Barrier, Riley Ruskamp May 2022

Development Of A Next-Generation Non-Proprietary Portable Concrete Barrier, Riley Ruskamp

Civil and Environmental Engineering Theses, Dissertations, and Student Research

Portable concrete barriers (PCBs) are segmented barriers made of precast concrete units that are connected by various load-bearing hardware. PCBs are typically used to shield work zones by redirecting errant vehicles upon impact with the barrier system. Most commonly-available PCBs have demonstrated performance issues arising from the sloped face of the barrier, which encourages vehicles to pitch and roll during impact, potentially resulting in vehicle rollover. Concerns also exist regarding the large dynamic deflections exhibited by these systems that can encroach upon the protected work zone or require anchoring to prevent large displacements. In addition to these concerns, the American ...


Risk Assessment Of Hazardous Material Transportation For Small And Tribal Communities, Harrison Redepenning May 2022

Risk Assessment Of Hazardous Material Transportation For Small And Tribal Communities, Harrison Redepenning

Civil and Environmental Engineering Theses, Dissertations, and Student Research

By and large transportation of hazardous materials (HazMat) across the US is increasing, with truck transportation as the most common method of transport. Smaller communities (population <5,000) and Native American communities often lack the economic and political influence to quantify the dangers that HazMat incidents present to the immediate and surrounding areas. Lack of such information is an impediment to adequate preparedness in cases of HazMat incidents. This research focuses on assessing the vulnerability of small and tribal communities in Nebraska to the impacts of highway HazMat incidents. This was done by estimating the expected number and type of HazMat incidents per population in each community. Additionally, statistical analysis was conducted on actual HazMat incidents to determine if small and Native American communities experience a higher rate of incidents per population and per HazMat VMT than large and other small communities respectively. For per population, it was found small versus large is statistically significant while Native American versus other small communities was not significant. For per HazMat VMT, neither comparison was found to be statistically significant. In estimated HazMat incidents, actual HazMat incidents per population, and actual HazMat incidents per HazMat VMT, small communities had higher mean values than their large counterparts. Communities on Native American reservation land experienced a higher estimated and lower actual HazMat incident rate per population than other small communities. For actual HazMat incidents per VMT, Native American communities had a higher rate than other small communities.

Advisor: Aemal Khattak


A Physical Model Of Deadmans Run, Quinn Brandt May 2022

A Physical Model Of Deadmans Run, Quinn Brandt

Civil and Environmental Engineering Theses, Dissertations, and Student Research

A physical model of Deadmans Run and a pair of railroad bridges was constructed to assess the impacts of the bridges on flood flows. Lower Platte South Natural Resources District is planning a series of improvements to Deadmans Run to improve flood conveyance capacity and remove approximately 500 homes and businesses from the floodplain. The rail bridges are located less than a mile from the confluence of Deadmans Run and Salt Creek, meaning the bridges present a significant bottleneck to the planned improvements. The physical model was used to characterize the drag effects caused by the bridges, which was used ...


Inactivation Of Salmonella In Black Peppercorn By Fluidization With Hydrogen Peroxide Vapor, Edel Summers May 2022

Inactivation Of Salmonella In Black Peppercorn By Fluidization With Hydrogen Peroxide Vapor, Edel Summers

Biological Systems Engineering--Dissertations, Theses, and Student Research

The purpose of the present study was to assess the effectiveness of hydrogen peroxide vapor (HPV) at inactivating Salmonella inoculated in whole black pepper when used as fluidizing gas media. HPV treatment was conducted at two different temperatures (45°C and 60°C) and two dwell times (30 min and 60 min). Microbial reduction and residual hydrogen peroxide were measured at three storage times: 0 h (immediately after treatment), 24 h and 48 h post-treatment. The effect of HPV on the quality of whole black peppercorn was evaluated 48 h post-treatment based on changes in piperine content, total phenolics, antioxidant ...


Symbolic Ns-3 For Efficient Exhaustive Testing, Jianfei Shao May 2022

Symbolic Ns-3 For Efficient Exhaustive Testing, Jianfei Shao

Computer Science and Engineering: Theses, Dissertations, and Student Research

Exhaustive testing is an important type of simulation, where a user exhaustively simulates a protocol for all possible cases with respect to some uncertain factors, such as all possible packet delays or packet headers. It is useful for completely evaluating the protocol performance, finding the worst-case performance, and detecting possible design or implementation bugs of a protocol. It is, however, time consuming to use the brute force method with current NS-3, a widely used network simulator, for exhaustive testing. In this paper, we present our work on Sym-NS-3 for more efficient exhaustive testing, which leverages a powerful program analysis technique ...


Assessment Of Manure Treatment Technology Adoption And Feedlot Runoff Monitoring Opportunities, Juan Carlos Ramos Tanchez Apr 2022

Assessment Of Manure Treatment Technology Adoption And Feedlot Runoff Monitoring Opportunities, Juan Carlos Ramos Tanchez

Biological Systems Engineering--Dissertations, Theses, and Student Research

Livestock products contain valuable nutrients that enhance human health, and their production generates positive local and national economic impacts. The livestock sector also deals with large quantities of environmentally important nutrients in manure. The purpose of this thesis is to further the aims of researchers and educators working at the intersection of livestock production and the environment to identify and promote best practices for livestock production and manure management that are economically and environmentally sustainable.

The second chapter explored options to evaluate nutrient flows in feedlot runoff at the pen scale. Pen scale monitoring is an important consideration for research ...


Machine Learning-Based Device Type Classification For Iot Device Re- And Continuous Authentication, Kaustubh Gupta Apr 2022

Machine Learning-Based Device Type Classification For Iot Device Re- And Continuous Authentication, Kaustubh Gupta

Computer Science and Engineering: Theses, Dissertations, and Student Research

Today, the use of Internet of Things (IoT) devices is higher than ever and it is growing rapidly. Many IoT devices are usually manufactured by home appliance manufacturers where security and privacy are not the foremost concern. When an IoT device is connected to a network, currently there does not exist a strict authentication method that verifies the identity of the device, allowing any rogue IoT device to authenticate to an access point. This thesis addresses the issue by introducing methods for continuous and re-authentication of static and dynamic IoT devices, respectively. We introduce mechanisms and protocols for authenticating a ...


Performance Of Concrete With Different Cement Finenesses And Nano-Activators, Brandon Faltin Apr 2022

Performance Of Concrete With Different Cement Finenesses And Nano-Activators, Brandon Faltin

Civil and Environmental Engineering Theses, Dissertations, and Student Research

The excessive shrinkage in modern concrete is the result of the construction industry in its quest to complete the job as soon as possible. In order to accomplish this, the fineness of cement was increased significantly in recent decades for a faster rate of strength gain. To combat the cement fineness and reverse the trend of shrinkage, the usage of coarse cements and nanoparticles should be strongly considered. The coarse cement is used to reduce the shrinkage of concrete, while the nanoparticle increases the early strength, alleviating the original concerns of reduced early strength when using coarse cement.

Work in ...


Using Cost Simulation And Computer Vision To Inform Probabilistic Cost Estimates, Shu Jing Ding Apr 2022

Using Cost Simulation And Computer Vision To Inform Probabilistic Cost Estimates, Shu Jing Ding

Dissertations & Theses: Construction Engineering and Management

Cost estimating is a critical task in the construction process. Building cost estimates using historical data from previously performed projects have long been recognized as one of the better methods to generate precise construction bids. However, the cost and productivity data are typically gathered at the summary level for cost-control purposes. The possible ranges of production rates and costs associated with the construction activities lack accuracy and comprehensiveness. In turn, the robustness of cost estimates is minimal. Thus, this study proposes exploring a range of cost and productivity data to better inform potential outcomes of cost estimates by using probabilistic ...


Characterizing And Predicting Human Visual Perception Of Unmanned Aerial Vehicle Gestures, Paul Fletcher Apr 2022

Characterizing And Predicting Human Visual Perception Of Unmanned Aerial Vehicle Gestures, Paul Fletcher

Computer Science and Engineering: Theses, Dissertations, and Student Research

Unmanned Aerial Vehicles (UAVs) are being used in public domains and hazardous environments where effective communication strategies are critical. UAV gesture techniques have been shown to communicate meaning to human observers and may be ideal in contexts that require lightweight systems such as unmanned aerial flight, however, this work may be limited to an idealized range of viewer perspectives. As gesture is a visual communication technique it is necessary to consider how the perception of a robot gesture may suffer from obfuscation or self-occlusion from some viewpoints. This thesis presents the results of three online user-studies that examine participants’ ability ...


Estimation Of Methane Emissions From Beef Cattle Manure In Nebraska, Noe Hernandez Apr 2022

Estimation Of Methane Emissions From Beef Cattle Manure In Nebraska, Noe Hernandez

Civil and Environmental Engineering Theses, Dissertations, and Student Research

The emission of methane from livestock production contributes to climate change. Cattle manure accounts for one-third of the total methane emission over the lifecycle of beef and dairy production and represents an opportunity to lower the environmental footprint of the beef industry. While models have been developed to estimate methane emissions from manure under certain types of manure storage methods, there is a lack of a user-friendly interface that agricultural or environmental engineers can use to estimate the methane emission from manure for specific regions. Therefore, the goal of this study was to build an interface to estimate methane emissions ...


Reducing Early-Age Shrinkage Cracks Of Bridge Decks And Rails, Soumitra Das, George Morcous, Jiong Hu Apr 2022

Reducing Early-Age Shrinkage Cracks Of Bridge Decks And Rails, Soumitra Das, George Morcous, Jiong Hu

UNL Student Research Days Posters, Graduate

Early-age shrinkage cracking of concrete bridge decks and rails accelerates the penetration of water and chemicals which leads to reinforcement corrosion, delamination, and eventually spalling. All this results in shorter service life, road closure, and costly repair. Development of Low-cement concrete(LCC) mix to reduce early age shrinkage crack through aggregate grading optimization was done in this research work. This approach also reduces concrete cost ($15-$20/cyd) (15–25%) and its carbon footprint (≈15%).


The Effect Of Store-To-Store Energy Transfers On The Global Dynamics Of Aircraft, Guilherme Mainieri Eymael, Keegan J. Moore Apr 2022

The Effect Of Store-To-Store Energy Transfers On The Global Dynamics Of Aircraft, Guilherme Mainieri Eymael, Keegan J. Moore

UNL Student Research Days Posters, Undergraduate

This study analyzes the energy transfer mechanisms when nonlinear devices (stores) are attached to a linear model airplane. For that, a reduced-order model (ROM) was derived to simulate the first two flexible modes of vibration of the primary structure (aircraft) with one store in each wing. Each store can either be locked or unlocked. When locked, it only contributes as mass-effect, and when unlocked, it adds nonlinearity to the system. Simulations were then performed with either both stores locked, one store unlocked, or both stores unlocked. It was found that the attachment of nonlinear stores in the ROM changes the ...


Understanding The Nonlinear Dynamics Governing Vertical-Lift Vehicles With Variable-Speed, Fixed Rotors, Stephanie Vavra, Micah Busboom, Aleea Stanford, Keegan Moore Apr 2022

Understanding The Nonlinear Dynamics Governing Vertical-Lift Vehicles With Variable-Speed, Fixed Rotors, Stephanie Vavra, Micah Busboom, Aleea Stanford, Keegan Moore

UNL Student Research Days Posters, Undergraduate

Problem: Traffic significantly limits travel in urban areas. • The NASA Urban Air Mobility Project is developing an air taxi as an alternative mean of transportation (Fig. 1).

Challenge: Operating rotors at different frequencies may cause the cabin to vibrate at high amplitudes. Such effects are currently unknown.

Objective: Understand the effect of variable speed rotors on passenger comfort.

From the reduced-order modeling simulations, it can be assumed that counteracting the rotor speed in-balances can reduce the displacement and vibrations experienced at the center of the wing. In other words, should a rotor not maintain its optimal operation speed, reducing the ...


Biomechanical Analysis Of Athletes Sprinting With Varying Degrees Of Resistance, Michaela Ott Apr 2022

Biomechanical Analysis Of Athletes Sprinting With Varying Degrees Of Resistance, Michaela Ott

Honors Theses, University of Nebraska-Lincoln

Utilizing resistance methods for sprinters is a common approach to their training. In this study, six athletes from the University of Nebraska-Lincoln Women’s Track and Field Team ran a series of sprints using a resistance machine to collect data regarding the change in power output, stride length, level of trunk tilt with respect to the ground, and acceleration throughout a distance of ten meters when different amounts of resistant forces were applied to the athlete. It was hypothesized that as resistance increased, power output would increase, stride length would decrease, the runners would become more horizontal resulting in a ...


A Low Jitter And Low Power Electronic Interface For Time-Of-Flight Positron Emission Tomography Silicon Photomultiplier Detectors, Matthew Romer Apr 2022

A Low Jitter And Low Power Electronic Interface For Time-Of-Flight Positron Emission Tomography Silicon Photomultiplier Detectors, Matthew Romer

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

A time-of-flight (TOF) detection system for a silicon photomultiplier (SiPM) is designed for the purpose of improving on existing technology for applications in positron emission tomography, with an emphasis on low power and low timing jitter. A reconstruction algorithm is implemented in Matlab to demonstrate the effect of TOF on the image quality per number of source events, as compared to systems restricted to line-of-response (LOR) data only. A case study is performed on SiPM functionality, behavioral modeling, and contemporary front-end amplification designs for a SiPM detector. A charge sensitive amplifier (CSA) circuit is modified for simultaneous collection of timing ...


Polyaniline/Cobalt Nanoparticle Composite Films, Rifat Mahbub Apr 2022

Polyaniline/Cobalt Nanoparticle Composite Films, Rifat Mahbub

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Polymer nanocomposites have been gaining attention because of the enhanced properties of the element materials it can offer. These composites have been used in biological sector as well as quantum computing and memory devices. These are also used as different kind of sensors. Polymer composites incorporated with magnetic nanoparticles can modify the magnetic property of the nanoparticles and that has huge potential to be used in different sort of applications.

This work aims to develop a polymeric nanocomposite incorporating a conducting polymer and magnetic nanoparticles. The influence of the conducting polymer on the magnetic property of the nanoparticles was investigated ...


Learning Domain Invariant Information To Enhance Presentation Attack Detection In Visible Face Recognition Systems, Jennifer Hamblin Apr 2022

Learning Domain Invariant Information To Enhance Presentation Attack Detection In Visible Face Recognition Systems, Jennifer Hamblin

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

Face signatures, including size, shape, texture, skin tone, eye color, appearance, and scars/marks, are widely used as discriminative, biometric information for access control. Despite recent advancements in facial recognition systems, presentation attacks on facial recognition systems have become increasingly sophisticated. The ability to detect presentation attacks or spoofing attempts is a pressing concern for the integrity, security, and trust of facial recognition systems. Multi-spectral imaging has been previously introduced as a way to improve presentation attack detection by utilizing sensors that are sensitive to different regions of the electromagnetic spectrum (e.g., visible, near infrared, long-wave infrared). Although multi-spectral ...


Seabem: An Artificial Intelligence Powered Web Application To Predict Cover Crop Biomass, Aime Christian Tuyishime, Andrea Basche Mar 2022

Seabem: An Artificial Intelligence Powered Web Application To Predict Cover Crop Biomass, Aime Christian Tuyishime, Andrea Basche

Honors Theses, University of Nebraska-Lincoln

SEABEM, the Stacked Ensemble Algorithms Biomass Estimator Model, is a web application with a stacked ensemble of Machine Learning (ML) algorithms running on the backend to predict cover crop biomass for locations in Sub-Saharan. The SEABEM model was developed using a previously developed database of crop growth and yield that included site characteristics such as latitude, longitude, soil texture (sand, silt, and clay percentages), temperature, and precipitation. The goal of SEABEM is to provide global farmers, mainly small-scale African farmers, the knowledge they need before practicing and benefiting from cover crops while avoiding the expensive and time-consuming operations that come ...


An Evaluation Of Tractors Tested At The Nebraska Tractor Test Lab And The Effect Of Epa Emission Standards Based Upon Average Pto Horsepower And Fuel Efficiency, Dalton Erickson Mar 2022

An Evaluation Of Tractors Tested At The Nebraska Tractor Test Lab And The Effect Of Epa Emission Standards Based Upon Average Pto Horsepower And Fuel Efficiency, Dalton Erickson

Honors Theses, University of Nebraska-Lincoln

Newly released tractor models are tested to ensure they meet advertising claims. This thesis utilizes tractor test data to analyze performance trends in tractors based upon their power take off (PTO) horsepower and fuel efficiency and it evaluates how the average fuel efficiency of tractors was affected by the introduction of emission standards by the United States Environmental Protection Agencies. In conclusion, tractors have shown continuous improvement and growth in both fuel efficiency and PTO horsepower, and emission standards have had a small, positive effect on tractors’ average fuel efficiency.


The Effect Of Store-To-Store Energy Transfers On The Global Dynamics Of Aircraft, Guilherme Mainieri Eymael Mar 2022

The Effect Of Store-To-Store Energy Transfers On The Global Dynamics Of Aircraft, Guilherme Mainieri Eymael

Honors Theses, University of Nebraska-Lincoln

This study analyzes the energy transfer mechanisms when nonlinear devices (stores) are attached to a linear model airplane. For that, a reduced-order model (ROM) was derived to simulate the first two flexible modes of vibration of the primary structure (aircraft) with one store in each wing. Each store can either be locked or unlocked. When locked, it only contributes as mass-effect, and when unlocked, it adds nonlinearity to the system. Simulations were then performed with either both stores locked, one store unlocked, or both stores unlocked. It was found that the attachment of nonlinear stores in the ROM changes the ...


Development Of Controller Area Network Bus Programming For Quarter-Scale Tractor Pulling Sled, Brittani Wacker Mar 2022

Development Of Controller Area Network Bus Programming For Quarter-Scale Tractor Pulling Sled, Brittani Wacker

Honors Theses, University of Nebraska-Lincoln

Usage of Controller Area Network (CAN) technology has allowed for advancements in many industries, including agriculture. Most importantly, its application is useful for refining data acquisition methods. With support from the Quarter-scale Tractor Design Team at UNL, this project united a CAN bus with the team’s current tractor pulling sled. The objectives were to install new instrumentation needed for the CAN bus and to program the updated system utilizing CAN data. The program needed to give the pulling sled functionality and the ability to read and log important pulling data. These goals were all accomplished by implementing new sensors ...


Design Of A Week-Long Introduction To Engineering Summer Camp To Increase Interest And Eagerness Of Stem In Young Children, Beth Cannon Mar 2022

Design Of A Week-Long Introduction To Engineering Summer Camp To Increase Interest And Eagerness Of Stem In Young Children, Beth Cannon

Honors Theses, University of Nebraska-Lincoln

For this creative project, a one-week camp curriculum was designed for elementary students (Grades 3-5) to introduce engineering. This work includes a rationale and camp curriculum. The rationale describes the research-based design of the curriculum. It outlines engineering basics and why and how to teach engineering to young students. The curriculum intends to introduce engineering to young children and excite the possibility of a future career. The following engineering disciplines are presented throughout the week of camp: mechanical, environmental, civil, electrical, and chemical. The first day of camp focuses on the basics of engineering. Following that, each day of camp ...


Challenges Of The Industrial Revolution Era 1.0 To 5.0 : University Digital Library In Indoensia, Merlin Apriliyanti, Ilham M Mar 2022

Challenges Of The Industrial Revolution Era 1.0 To 5.0 : University Digital Library In Indoensia, Merlin Apriliyanti, Ilham M

Library Philosophy and Practice (e-journal)

This study explains the development of the world of libraries to establish a very close relationship with the world of information technology. For this reason, facilities and infrastructure are needed to facilitate data and information retrieval quickly and accurately. Facing the challenges of the Industrial Revolution 5.0 era by utilizing information technology, libraries must also adapt to the times. Because the library has an important role, among others, as a source of information and the development of knowledge. Used libraries are still conventional to be converted into digital libraries. In essence, this development represents the desire of library users ...


A Greenhouse Gas Emissions Inventory For Nebraska: Livestock And Coal Loom Large, Eric R. Holley, Adam Liska Jan 2022

A Greenhouse Gas Emissions Inventory For Nebraska: Livestock And Coal Loom Large, Eric R. Holley, Adam Liska

Adam Liska Papers

Mitigation of climate change requires the systematic identification and cataloging of emissions sources at city, state, and national levels. In this study, an inventory of annual greenhouse gas emissions from the state of Nebraska was created based on industry data, and emissions inventories were completed each year from 1990 to 2016. Nebraska’s net emissions were found to increase from 56.2 million metric tons of carbon dioxide equivalents (MMtCO2e) in 1990 to 87.4 MMtCO2e in 2016. Agriculture was found to be the sector with the most emissions (36 MMtCO2e) followed by electricity ...


Pilot-Scale Spinning And Sucrose-Tetra-Aldehydes-Crosslinking Of Feather-Derived Protein Fibers With Improved Mechanical Properties And Water Resistance, Bingnan Mu, Faqrul Hassan, Qianmei Wu, Yiqi Yang Jan 2022

Pilot-Scale Spinning And Sucrose-Tetra-Aldehydes-Crosslinking Of Feather-Derived Protein Fibers With Improved Mechanical Properties And Water Resistance, Bingnan Mu, Faqrul Hassan, Qianmei Wu, Yiqi Yang

Faculty Publications - Textiles, Merchandising and Fashion Design

Pliable and water-resistant protein fibers from feathers were developed via continuous one-step spinning and crosslinking using sucrose-tetra-aldehydes. Though flexible protein fibers from feathers were developed, poor wet stability and low tenacity still limit the large and high-end applications of feather-derived fibers. Despite that saccharide aldehydes are considered as an efficient and sustainable crosslinker, substantial concerns such as generation of formaldehyde, high consumption of modifiers, loss of mechanical properties, yellowing, and decline in dyeability of fibers, exist after crosslinking. In this work, we controlled structures of crosslinkers and incorporated disaccharide-tetra-aldehydes into a continuous wet-spinning line. No formaldehyde was generated in the ...


Geospatial Distribution Of Age-Adjusted Incidence Of The Three Major Types Of Pediatric Cancers And Waterborne Agrichemicals In Nebraska, Balkissa S. Ouattara, Jagadeesh Puvvula, Azar Abadi, Siddhi Munde, Alan S. Kolok, Shannon Bartelt-Hunt, Jesse E. Bell, Christopher S. Wichman, Eleanor Rogan Jan 2022

Geospatial Distribution Of Age-Adjusted Incidence Of The Three Major Types Of Pediatric Cancers And Waterborne Agrichemicals In Nebraska, Balkissa S. Ouattara, Jagadeesh Puvvula, Azar Abadi, Siddhi Munde, Alan S. Kolok, Shannon Bartelt-Hunt, Jesse E. Bell, Christopher S. Wichman, Eleanor Rogan

Civil and Environmental Engineering Faculty Publications

This study was conducted to examine, at the county level, the relationship between pediatric cancer incidence rate and atrazine and nitrate mean concentrations in surface and groundwater. A negative binomial regression analysis was performed to investigate the association between central nervous system (CNS) tumors, leukemia, lymphoma, and atrazine and nitrate mean concentrations in groundwater. The age-adjusted brain and other CNS cancer incidence was higher than the national average in 63% of the Nebraska counties. After controlling for the counties socio-economic status and nitrate concentrations in groundwater, counties with groundwater atrazine concentrations above 0.0002 μg/L had a higher incidence ...


Probability-Based Crack Width Estimation Model For Flexural Members Of Underground Rc Box Culverts, Sang-Hyo Kim, Syed Haider Ali Shah, Sang-Kyun Woo, Inyeop Chu, Chungwook Sim Jan 2022

Probability-Based Crack Width Estimation Model For Flexural Members Of Underground Rc Box Culverts, Sang-Hyo Kim, Syed Haider Ali Shah, Sang-Kyun Woo, Inyeop Chu, Chungwook Sim

Civil and Environmental Engineering Faculty Publications

Crack control for slabs and beams in current design practices in Korea are based on the Frosch’s model, which is adapted in ACI 318. It is more difficult to have consistent quality control in underground construction sites, such as the RC box culverts used for electric power distribution built below the ground level. There are more discrepancies between the as-built dimensions and the design dimensions provided in drawings in these structures. Due to this variability in construction error, the crack widths measured in such structures have higher potential to have more differences than the calculated values. Although crack control ...