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Full-Text Articles in Engineering

Effects Of Nutrient Level And Growth Rate On Mutation And Conjugation Processes That Confer Antibiotic Resistance To E. Coli, Mohammadreza Shafieifini Aug 2019

Effects Of Nutrient Level And Growth Rate On Mutation And Conjugation Processes That Confer Antibiotic Resistance To E. Coli, Mohammadreza Shafieifini

Civil Engineering Theses, Dissertations, and Student Research

Antibiotic resistance genes (ARGs) may enter surface water with the discharge of treated wastewater. Conjugation is a main mechanism for the horizontal gene transfer of ARGs from wastewater microbiome to the microbiome indigenous to surface water. However, little is known about how environmental factors affect the conjugation process of ARGs.

In this thesis, an extensive research related to spreading antibiotic resistance genes in the environment is reported. The project investigated how environmental parameters may affect the rate of dissemination of ARGs and in what extent the resistance level of the population is changed after mutation and conjugation event. The chemostat ...


Probabilistic Analysis Of Slide-Rocking Structures Under Earthquake Loads, Taylor J. Knickerbocker Aug 2019

Probabilistic Analysis Of Slide-Rocking Structures Under Earthquake Loads, Taylor J. Knickerbocker

Civil Engineering Theses, Dissertations, and Student Research

Estimates of rare seismic hazard are essential for the resilience of critical infrastructure and facilities. However, these estimates are highly uncertain at long return periods due to the lack of observed earthquake records. Several ground motion prediction equations have been proposed to close this gap and estimate rare seismic demands; however, these models were developed based on more moderate earthquake records and can yield physically unrealizable ground motions when extrapolated to long return periods. For this reason, seismologists have proposed using precariously balanced rocks (PBRs) as a way to constrain rare seismic hazard. PBRs are a type of fragile geologic ...


Numerical Simulation Of Diffuse Ultrasonic Waves In Concrete, Hossein Ariannejad Aug 2019

Numerical Simulation Of Diffuse Ultrasonic Waves In Concrete, Hossein Ariannejad

Civil Engineering Theses, Dissertations, and Student Research

Concrete can be subject to various type of damages. Some damages such as Alkali Silica Reaction (ASR) tend to start from the inside, where there is no easy way to identify or evaluate them in the early stage. The study of ultrasonic waves scatterings in non destructive testing (NDT) methods play a major role in identifying such damages. In an ultrasonic test, high frequency ultrasonic waves are used to interrogate the internal structure of concrete material, where the coarse aggregates and microcracks cause multiple scattering of ultrasonic waves. Experimental studies have demonstrated that diffuse ultrasonic waves scattered by boundaries, coarse ...


Sustainability Assessment Of U.S. Beef Processing And Its Antimicrobial Systems, Shaobin Li Jul 2019

Sustainability Assessment Of U.S. Beef Processing And Its Antimicrobial Systems, Shaobin Li

Civil Engineering Theses, Dissertations, and Student Research

With the increasing meat demand and awareness of sustainability, concerns have been raised regarding the sustainability of beef production and processing. However, scarce data and inadequate sustainability assessment frameworks for the U.S. beef processing industry limit the ability to develop new technologies and policies comprehensively without shifting sustainability burdens. To fill those gaps, various assessments of the U.S. beef processing industry were conducted from multiple perspectives regarding the environmental, economic, microbial effectiveness of its antimicrobial systems, and human health impacts from foodborne illness, occupational hazards, and environmental pollution.

First, process-level water and energy usage at a typical large-size ...


Restricted Crossing U-Turns At Rural Intersections, Timothy Adams May 2019

Restricted Crossing U-Turns At Rural Intersections, Timothy Adams

Civil Engineering Theses, Dissertations, and Student Research

This study examines the potential for replacing the standard intersection design at two-way stop control (TWSC) and all-way stop control (AWSC) intersections along rural highways with a roundabout or a restricted crossing u-turn (RCUT) facility. The geometry of the RCUT design prohibits left and through movements from the side road, and provides a u-turn location downstream from the main crossing. This type of facility has been implemented for rural highways extensively in other states and has the potential to serve as a cost-effective solution to improve roadway safety within Nebraska.

Comparative analysis is conducted for three site locations (Humphrey, Madison ...


Biofiltration Of Volatile Organic Compounds Emitted At Ethanol Plants, Christopher Arthur Duerschner May 2019

Biofiltration Of Volatile Organic Compounds Emitted At Ethanol Plants, Christopher Arthur Duerschner

Civil Engineering Theses, Dissertations, and Student Research

Ethanol manufacturing is an important and growing sector in the biofuels marketplace. At ethanol plants, the control of volatile organic compound containing emissions from fermentation tanks and distillers dried grains with solubles driers is accomplished through the use of air scrubbers and regenerative thermal oxidizers. The operation of these control units imposes substantial operating costs for the ethanol plant. Biotrickling filters have the ability to replace scrubbers and regenerative thermal oxidizers resulting in significant economic and environmental benefits. Two biotrickling filters were operated in parallel under acetaldehyde loadings ranging from 4 to 136 gm-3hr-1. To examine the ...


Full Scale 13-Story Building Implosion And Collapse: Effects On Adjacent Structures, Kanchan Devkota May 2019

Full Scale 13-Story Building Implosion And Collapse: Effects On Adjacent Structures, Kanchan Devkota

Civil Engineering Theses, Dissertations, and Student Research

Two dormitory halls at the University of Nebraska-Lincoln known as Cather and Pound halls were demolished via controlled implosion on December 22, 2017. Cather and Pound halls were two thirteen-story reinforced concrete structures. The demolition of these two structures included the implosion of controlled charges at selected columns on alternating floors which initiated the progressive collapse of these structures. Three nearby structures in the vicinity of Cather and Pound halls were instrumented with high sensitivity uniaxial piezoelectric accelerometers to record the response of the adjacent structures during the event of the implosion and the progressive collapse. While these two thirteen-story ...


Application Of Remote Sensing Technology In Water Resources Management, Mahesh Pun May 2019

Application Of Remote Sensing Technology In Water Resources Management, Mahesh Pun

Civil Engineering Theses, Dissertations, and Student Research

The primary goal of this dissertation was to leverage the capabilities of remote sensing technology for capturing detailed spatial information at different spatial resolutions to monitor agricultural crops and generate accurate input datasets for water resources models. This dissertation is divided into three different research studies. In the first study, a remote sensing classification method was developed for classifying irrigated and non-irrigated fields that integrates Vegetation indices with surface energy balance fluxes. The method was applied in the COHYST2010 hydrological model region with wide climate variation and to multiple growing seasons with results that were 92.1% accurate and explained ...


Development Of A Mash Tl-4 Steel, Side-Mounted, Beam-And-Post, Bridge Rail, Oscar Pena Apr 2019

Development Of A Mash Tl-4 Steel, Side-Mounted, Beam-And-Post, Bridge Rail, Oscar Pena

Civil Engineering Theses, Dissertations, and Student Research

A new steel, side-mounted, beam-and-post, bridge rail was designed, crash-tested, and evaluated according to safety performance guidelines included in the American Association of State Highway and Transportation Officials Manual for Assessing Safety Hardware (MASH) for Test Level 4 (TL-4). The new bridge rail system was designed to be compatible to multiple concrete bridge decks utilized by the States of Illinois and Ohio. Bridge rail configurations were designed and optimized based on weight per foot, constructability, and safety. Post-to-rail and rail-to-rail connections were designed for the new bridge rail. Several concepts for these connections were configured, and after discussion with representatives ...


Development Of Post-To-Deck Connections For Use In A Mash Tl-4 Steel-Tube Bridge Rail, Pascual Mauricio Apr 2019

Development Of Post-To-Deck Connections For Use In A Mash Tl-4 Steel-Tube Bridge Rail, Pascual Mauricio

Civil Engineering Theses, Dissertations, and Student Research

A new post-to-deck connection was designed for mounting an upcoming Manual for Assessing Safety Hardware (MASH) Test Level 4 steel-tube bridge rail to the side of the bridge deck to limit impact load transferred to the deck and to minimize the propensity for deck damage during impacts. With preference for the bridge rail system to be compatible for use on all deck configurations, the Illinois and Ohio Departments of Transportation desired the new system to attach to bridge decks comprised of concrete slabs or precasted prestressed, concrete box-beam girders.

A new post-to-deck connection for a new MASH 2016 TL-4 steel-tube ...


Using Theoretical And Experimental Particle Packing For Aggregate Gradation Optimization To Reduce Cement Content In Pavement Concrete Mixtures, Miras Mamirov Apr 2019

Using Theoretical And Experimental Particle Packing For Aggregate Gradation Optimization To Reduce Cement Content In Pavement Concrete Mixtures, Miras Mamirov

Civil Engineering Theses, Dissertations, and Student Research

The main objective of this study was to evaluate the effect of aggregate particle packing optimization and cement reduction on Nebraska slip-form pavement concrete performance. A literature review was conducted to examine different aggregate optimization tools, quality control tests, and historical data of Nebraska Department of Transportation (NDOT) mixtures. It was found that the Modified Toufar Model has good potential in optimizing particle packing and predicting packing degrees. The combined void content test was found to be useful to experimentally justify optimized aggregate gradations. Two specific pavement concrete workability tests, i.e., the Box Test and the VKelly Test, were ...


Simulation Of Antimicrobial Resistance Gene Fate In Narrow Grass Hedges, Marzieh Khedmati Apr 2019

Simulation Of Antimicrobial Resistance Gene Fate In Narrow Grass Hedges, Marzieh Khedmati

Civil Engineering Theses, Dissertations, and Student Research

Vegetative Filter Strips (VFS) are used for controlling the volume of runoff and decreasing the contaminants in runoff before entering the water bodies. Many studies investigated the role of VFS in sediment and nutrient removal, but little is known about their efficiency in the removal of emerging contaminants such as antimicrobial resistance genes (ARGs). VFSMOD was used to simulate the efficiency of VFS in this regard. The objectives of this study were to calibrate the VFSMOD with some experimental data and asses the efficiency of the model in simulating the filter behavior in removing ARGs. The tests were conducted in ...


Proportion And Evaluation Of Ultra-High Performance Concrete Using Local Materials, Flavia Ribeiro Furtado De Mendonca Apr 2019

Proportion And Evaluation Of Ultra-High Performance Concrete Using Local Materials, Flavia Ribeiro Furtado De Mendonca

Civil Engineering Theses, Dissertations, and Student Research

Ultra-high performance concrete (UHPC) is a new class of concrete that has superior workability, as well as mechanical and durability properties that far exceed those of conventional concrete. To achieve these properties, a very dense internal structure and the very low water-to-binder ratio (w/b) generally are necessary. While particle packing models are typically used to design UHPC, due to the complexity of the composition interaction and characteristics of UHPC, these models might not necessarily provide the best design, which leads to the need of experimental study to justify UHPC performance. The evaluation of the impact of various design parameters ...


Assessing Impact And Blast Resilience Of Polymer Coated Cementitious Materials, Murtaza Nalwala, Gabriel Nsengiyumva, Yong-Rak Kim Jan 2019

Assessing Impact And Blast Resilience Of Polymer Coated Cementitious Materials, Murtaza Nalwala, Gabriel Nsengiyumva, Yong-Rak Kim

Civil Engineering Theses, Dissertations, and Student Research

RESEARCH MOTIVATION: The bridge piers are highly vulnerable to the impact and blast loads. The position in which they are constructed makes it difficult to install protective devices around them. By the current AASHTO standard, it is possible to under-design bridge piers for commercial vehicle impacts and other events such as blast.

OBJECTIVE: To improve impact and blast resilience of bridge piers using polymeric coatings.

CONCLUSION • Polymer coating of Portland cement concrete can be achieved with a good bonding. • The polymeric coating seem to improve impact resilience of Portland cement concrete by increasing absorbed impact energy (i.e., area underneath ...