Digital Commons Network^™

Development Of High Value Oil Traits Using The Model Oilseed Crop Camelina Sativa, Evan Updike

Department of Biochemistry: Dissertations, Theses, and Student Research

Plant oils are an important source of food, fuel, and feed in our society today. The oil found in the seeds of plants is composed almost entirely of triacylglycerol (TAG) molecules, which consist of three fatty acids esterified to a glycerol backbone. As crude oil supplies decline, vegetable oils are gaining traction as a renewable substitute to petroleum-based materials in fuels, lubricants, and specialty oleochemicals. However, as it currently stands vegetable oils do not possess the properties necessary to fill the void of a petroleum free world.

To address this problem, plant biotechnologists have done extensive work on genetic engineering …

Almost Speechless: Representations Of Womanhood And Female Voices In Turn­-Of-­The-Century American Novels, Carmen Sylvia Smith

Department of English: Dissertations, Theses, and Student Research

In this dissertation, I close read four turn-­of-­the-­century American novels by Henry James, Kate Chopin, Charles Chesnutt, and Willa Cather to analyze how the voices and silences of fictional women characters work to disrupt cultural ideals about womanhood. Examining which aspects of the characters’ identities are expressed in direct dialogue and which traits are conveyed to the reader through narrative devices reveals how cultural ideals about womanhood restrict women’s self-­expressive autonomy and work to exclude female voices from the public sphere.

Chapter One examines Henry James’s The Bostonians (1886) and how erotic rivals Olive Chancellor and Basil Ransom compete to …

Getting Our Act(Ivism) Together: Understanding And Fostering Secondary And University Teacher Advocacy Collaborations, Nicole E. Green

Department of English: Dissertations, Theses, and Student Research

Given the deleterious effects on students and teachers caused by ever-expanding neoliberal approaches to K-16 English Language Arts and literacy education policy, this dissertation argues effective policy advocacy and reform absolutely depends on collaborations among secondary ELA and postsecondary composition and English education teacher-scholars. Borrowing from the traditions of participant action research, this project traces the experiences of a small group of secondary and postsecondary English educators across the span of a 16-month collaborative advocacy project. By examining a range of data including recordings of group meetings, interviews, and written reflections through the lens of activity theory, this study seeks …

Development Of Tractor Instrumentation System: Hydraulics, And Controller Area Network (Can) Data Analysis Of Agricultural Machinery, Chee Town Liew

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

The tractor is a very important piece of machinery in agriculture, and it has been evolving and progressing over the years with improved and increasingly complex functionality. Controller Area Network (CAN) has been incorporated into tractors and other machinery with SAE J1939 and ISO 11783 standards, serving as the communication bus for various on-board electronic controller units (ECUs), and carries various machine operation data that can be used for analyzing machine performance. Investigation of data extraction from CAN messages was conducted by examining the SAE J1939 and ISO 11783 standards. A case study on CAN bus data analysis for a …

Quantifying The Combined Effect Of Abiotic Factors On The Decomposition Of Organic Matter In Semiarid Grassland Soils, Elnazsadat Hosseiniaghdam

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

Grassland ecosystems play a critical role in the global carbon cycle, and their cumulative carbon dioxide (CO₂) emissions can be affected by animal grazing where litter (i.e., dead plant material) is trampled into the soil. However, the subsequent effects of trampling on litter decomposition are not well understood. Meanwhile, abiotic factors, especially temperature and soil moisture, are known to strongly affect litter decomposition. Due to the very small number of published studies that have considered litter placement, either litter on top of soil or litter mixed with soil as a factor in litter decomposition under different temperature and …

Designing Gfrp-Reinforced Tilt-Up Wall Panels, Fray F. Pozo-Lora, Marc Maguire

Durham School of Architectural Engineering and Construction: Faculty Publications

Tilt-up construction was effectively enabled on a wide scale in 1979, when the ACI committee 551 report on Tilt-up construction was published, the Recommended Tilt-Up Wall Design, aka, the Yellow Book and the subsequent ACI-SEASC Task, aka the Green Book, and another Tilt-up design and construction manual developed by the ACI in 1988. The Tilt-up Concrete Association was created in 1986 by a group of industry professionals who had the need of an organization dedicated to the industry. ACI 551 maintains a document outlining the standard practice for contemporary Tilt-up design and construction. The ACI 551 document does not consider …

Bootstrap Percolation On Random Geometric Graphs, Alyssa Whittemore

Department of Mathematics: Dissertations, Theses, and Student Research

Bootstrap Percolation is a discrete-time process that models the spread of information or disease across the vertex set of a graph. We consider the following version of this process:

Initially, each vertex of the graph is set active with probability p or inactive otherwise. Then, at each time step, every inactive vertex with at least k active neighbors becomes active. Active vertices will always remain active. The process ends when it reaches a stationary state. If all the vertices eventually become active, then we say we achieve percolation.

This process has been widely studied on many families of graphs, deterministic …

Voltage-Controlled Magnetization In Chromia-Based Magnetic Heterostructures, William Echtenkamp

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Spintronics promises a new generation of low-power, high-speed, non-volatile memory and logic devices. Heterostructures based on magnetoelectric chromia enable the direct manipulation of magnetization by applied electric fields and emerged as a promising building block for spintronic devices. In this dissertation, several interesting emergent magnetic properties arising in these device-enabling building blocks are examined. In some cases, exchange coupling at the interface between the magnetoelectric antiferromagnet and an adjacent ferromagnet stabilizes the interfacial antiferromagnetic domain state against the electrically induced rotation of the bulk spin structure. Upon magnetically cycling the ferromagnet, the magnetoelectric antiferromagnet relaxes towards a commensurate spin structure …

The Design, Creation, And Cognitive Evaluation Of Ranking Tasks In Introductory Astronomy, Emily A. Welch

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Ranking tasks are a type of interactive formative assessment. They allow students to explore a concept by ranking similar situations for a specified variable, preferably without computation of that variable. I created two sets of introductory astronomy ranking tasks: the first connects the Hertzsprung–Russell (HR) diagram and the Stephan-Boltzmann luminosity equation; the second uses the transit method (TM) to rank exoplanets by comparing the depth, duration, and frequency of transits.

These tasks are designed within the constructivist pedagogical framework. They require students to call upon their own relevant schema to establish an assessment rule by which to rank the tasks. …

Thermomechanical Modeling In Laser Powder Bed Fusion Additive Manufacturing Using Graph Theory: Application To Prediction Of Recoater Crash, Md Humaun Kobir

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This work pertains to the laser powder bed fusion (LPBF) additive manufacturing process. The objective of this thesis is to predict a frequently occurring type of thermal-induced process failure in LPBF called recoater crash. To ascertain the likelihood of a recoater crash before the part is printed, we develop and apply a computationally efficient thermomechanical modeling approach based on graph theory.

Despite its demonstrated ability to overcome the design and processing constraints of conventional subtractive and formative manufacturing, the production-level scaleup of LPBF is hindered by frequent build failures. For example, the part often deforms as it is being printed …

When Did You Stop Singing? Elementary Boys' Attitudes And Self-Efficacy Toward The Act Of Singing, Eric D. Wyler

Glenn Korff School of Music: Dissertations, Theses, Student Creative Work, and Performances

The “missing males” epidemic is one which has baffled music educators and researchers for decades. Many research studies have been conducted to explore why boys choose to not be involved in choral ensembles at their middle and high schools. These studies list numerous retention/recruitment strategies; however, the problem remains. Many boys decide before they reach middle school whether they like to sing. The purposes of this study are to examine elementary age boys’ attitudes toward singing and determine at what grade level, if any, there is a significant difference in boys’ attitudes, to search for a relationship between boys’ attitudes …

Afterschool Club: German For K-5, Justin Solheim

Honors Program: Expanded Learning Clubs

The lessons found in this paper were designed for a group of 20-25 elementary schools students in downtown Lincoln, NE. The students were split into two groups: K-2 and 3-5. Through a variety of activities, the students learned the basics of the German language and culture. Many of the lessons are simple and do not require difficult thinking, as this was a summer club. Instead, they allow students to collaborate, move around, color, and solve puzzles.

Leveraging Unmanned Aerial System Remote Sensing To Inform Energy And Water Balance Models For Spatial Soil Water Content Monitoring And Irrigation Management, Mitchell S. Maguire

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

Irrigation has provided a means to produce more food and fiber throughout the world, converting low producing land into high yielding cropping systems in certain scenarios. The managing of irrigation has taken on various approaches as different locations have been constrained by different factors. Certain areas have significant ground and surface water available for irrigation while other areas struggle to meet irrigation demands due to limited water resources. These factors, along with the desire to increase crop water use efficiency, has provided the motivation to better understand crop water demands spatially within a field. A sub-field scale irrigation management study …

Integrated Geophysical Analysis Over Bathymetrists Seamounts And The Sierra Leone Rise, Alexa Fernandez

UCARE: Research Products

The Bathymetrists Seamounts (BSM) are located northeast of the Sierra Leone Rise in the Atlantic Ocean. The northern seamounts have a southwest to northeast trend which is contrary to the current eastward motion of the African tectonic plate where they reside. The geological history and crustal structures of these features are poorly understood. The goal of this study is to integrate multiple geophysical data to better understand the crustal architecture and tectonic history of the BSM.

The seismic refraction study from Jones et al. (2015) was used as the baseline for isostatic modeling. This dataset suggested the presence of magmatic …

Effect Of Radiofrequency Assisted Thermal Processing On The Structural, Functional And Biological Properties Of Egg White Powder, Alisha Kar

Department of Food Science and Technology: Dissertations, Theses, and Student Research

Radiofrequency (RF) assisted thermal processing is a novel and energy-efficient method used for pasteurization, which heats the product volumetrically as opposed to traditional hot room (HR) pasteurization. RF-assisted thermal processing accelerates the heating rate of egg white powder (EWP), which has a low thermal conductivity and further affect its gelling properties. The effect of processing methods (RF and HR) due to pH and treatment temperature combination was monitored by subjecting neutral EWP (6.4 pH) to 70 and 80 ℃ and alkaline EWP (pH 9.9) samples to 70 ℃ over 0, 5, 10, 15 and 20 d. At 80 ℃ and …

Finite Element Modelling And Exergy Analysis Of A Solar Thermal Hollow Fiber Vacuum Membrane Distillation System, Benjamin Shuldes

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

A finite element model was developed to investigate the performance of a vacuum membrane distillation module under various operating conditions and membrane parameters. Porosity, tortuosity, pore diameter, membrane thickness, and fiber length were varied along with feed temperature, velocity, and flow configuration. In all cases, boundary layer polarization phenomena were seen to inhibit the performance of the module. At certain conditions, for a 7.5 cm fiber, the reduction in permeate flux from 65 LMH (Liter/m²/h) at the inlet to below 45 LMH at the outlet of the fibers was observed. In most cases, salt concentration polarization was the …

Spatiotemporal Trends In Bacterial Diversity Across Three Watersheds Within The Platte River Basin, Nebraska, Esther Perisho

School of Natural Resources: Dissertations, Theses, and Student Research

River bacteria are understudied despite being critical components of river ecosystems. There are even fewer studies considering bacteria communities at large spatiotemporal scales, which may provide insight into drivers of community assembly. We investigated differences in bacterial diversity across environmental gradients within three sub-basins nested in the Platte River Basin, Nebraska. Surface water samples were collected weekly at 36 sites from May to September by the Nebraska Department of Environment and Energy (NDEE) in 2019. Bacterial communities were sequenced using the Illumina MiSeq platform. Sub-basins had similar counts of unique amplicon sequence variants (ASVs) but different community structures. These structural …

Genetic Parameter Estimates For Bull Prolificacy And Its Relationship With Scrotal Circumference In A Commercial Beef Cattle Population, Chad A. Russell, E John Pollak, Matthew L. Spangler

Department of Animal Science: Faculty Publications

The commercial beef cattle industry relies heavily on the use of natural service sires. When artificial insemination is deemed difficult to implement, multisire breeding pastures are used to increase reproductive rates in large breeding herds or to safe-guard against bull injury during the breeding season. Although each bull might be given an equal opportunity to produce offspring, evidence suggest that there is substantial variation in the number of calves sired by each bull in a breeding pasture. With the use of DNA-based paternity testing, correctly assigning calves to their respective sires in multisire pastures is possible and presents an opportunity …

Developing A Database Of Seismic Data Over The Cascadia Subduction Zone, Khawlh Al Farsi

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

An inevitable megathrust earthquake is expected in the Cascadia subduction zone that will affect the population of the coast of southwestern British Columbia and the northwest of the United States. In this active tectonic margin, the Juan de Fuca oceanic plate is subducting beneath the North American continental plate, causing unevenly distributed seismic activity. The major goal of this geophysical research project is to study the tectonic structures of the Cascadia subduction zone in order to comprehend the geology of the region and investigate the seismic hazards. The primary objective of this project is to develop a geophysical database of …

Metabolic Modeling And Omics-Integrative Analysis Of Single And Multi-Organism Systems: Discovery And Redesign, Mohammad Mazharul Islam

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Computations and modeling have emerged as indispensable tools that drive the process of understanding, discovery, and redesign of biological systems. With the accelerating pace of genome sequencing and annotation information generation, the development of computational pipelines for the rapid reconstruction of high-quality genome-scale metabolic networks has received significant attention. These models provide a rich tapestry for computational tools to quantitatively assess the metabolic phenotypes for various systems-level studies and to develop engineering interventions at the DNA, RNA, or enzymatic level by careful tuning in the biophysical modeling frameworks. in silico genome-scale metabolic modeling algorithms based on the concept of optimization, …

Deir (Diversity, Equity, Inclusion And Respect) In Chemistry Libraries, Kiyomi D. Deards

University of Nebraska-Lincoln Libraries: Faculty Publications

Kiyomi Deards will examine a selection of past, present, and future DEIR strategies used by herself and University of Nebraska–Lincoln Libraries. Additionally, she will highlight DEIR strategies that individuals, departments, and organizations can pursue with varying levels of support.

Distributed Neural Network Based Architecture For Dddos Detection In Vehicular Communication Systems, Nicholas Jaton

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

With the continued development of modern vehicular communication systems, there is an ever growing need for cutting edge security in these systems. A misbehavior detection systems (MDS) is a tool developed to determine if a vehicle is being attacked so that the vehicle can take steps to mitigate harm from the attacker. Some attacks such as distributed denial of service (DDoS) attacks are a concern for vehicular communication systems. During a DDoS attack, multiple nodes are used to flood the target with an overwhelming amount of communication packets. In this thesis, we investigated the current MDS literature and how it …

Evaluating The Perspectives Of Those With Severe Physical Impairments While Learning Bci Control Of A Commercial Augmentative And Alternative Communication Paradigm, Kevin Pitt, Jonathan S. Brumberg

Department of Special Education and Communication Disorders: Faculty Publications

Augmentative and alternative communication (AAC) techniques can provide access to communication for individuals with severe physical impairments. Brain–computer interface (BCI) access techniques may serve alongside existing AAC access methods to provide communication device control. However, there is limited information available about how individual perspectives change with motor-based BCI-AAC learning. Four individuals with ALS completed 12 BCI-AAC training sessions in which they made letter selections during an automatic row-column scanning pattern via a motor-based BCI-AAC. Recurring measures were taken before and after each BCI-AAC training session to evaluate changes associated with BCI-AAC performance, and included measures of fatigue, frustration, mental effort, …

Bovine Mammary Alveolar Mac-T Cells Afford A Tool For Studies Of Bovine Milk Exosomes In Drug Delivery, Mojisola Ogunnaike

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

Bovine milk exosomes (BMEs) have attracted attention as vehicles for delivering RNA therapeutics. BMEs originate in mammary alveolar cells. Here, we determined whether bovine mammary alveolar MAC-T cells are a promising tool to assess RNA delivery by BMEs. MAC-T cells exosomes (MAC-T BMEs) and BMEs were harvested by differential ultracentrifugation. Exosome size, morphology, microRNA content and marker proteins were assessed using nanoparticle tracking analysis, transmission electron microscopy, real-time PCR and immunoblot analysis, respectively. MAC-T cells were genetically engineered to secrete MAC-T BMEs endogenously labeled with a near-infrared fluorescent protein and tissue distribution was compared to fluorophore-labeled BMEs following intravenous injection …

Dynamical Variations Of The Global Covid-19 Pandemic Based On A Seicr Disease Model: A New Approach Of Yi Hua Jie Mu, Xia Wang, Gang Yin, Zengyun Hu, Daihai He, Qianqian Cui, Xiaomei Feng, Zhidong Teng, Qi Hu, Jiansen Li, Qiming Zhou

Department of Earth and Atmospheric Sciences: Faculty Publications

The ongoing coronavirus disease 2019 (COVID-19) pandemic has caused more than 150 million cases of infection to date and poses a serious threat to global public health. In this study, global COVID-19 data were used to examine the dynamical variations from the perspectives of immunity and contact of 84 countries across the five climate regions: tropical, arid, temperate, and cold. A new approach named Yi Hua Jie Mu is proposed to obtain the transmission rates based on the COVID-19 data between the countries with the same climate region over the Northern Hemisphere and Southern Hemisphere. Our results suggest that the …

Semi Real-Time Detection Of Subsurface Consolidation Defects During Concrete Curing Stage, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Subsurface consolidation defect is a common issue in concrete pavement construction, and the hidden defects often require costly repairs after project delivery. Therefore, being able to identify this type of defect during construction will enable contractor to conduct quick repairs to avoid costly post-construction rework. In this paper a semi real-time detection approach using infrared thermography is introduced. The developed approach utilizes the hydration heat during curing time to identify the subsurface voids based on the regional temperature contrast. Experimental studies were conducted using artificial void-defect in different sizes and depths. The thermographic analysis is employed to locate the void-defects …

Near-Optimal Learning Of Tree-Structured Distributions By Chow-Liu, Arnab Bhattacharyya, Sutanu Gayen, Eric Price, N. V. Vinodchandran

Department of Mathematics: Faculty Publications

We provide finite sample guarantees for the classical Chow-Liu algorithm (IEEE Trans. Inform. Theory, 1968) to learn a tree-structured graphical model of a distribution. For a distribution P on Σⁿ and a tree T on n nodes, we say T is an ε-approximate tree for P if there is a T-structured distribution Q such that D(P || Q) is at most ε more than the best possible tree-structured distribution for P. We show that if P itself is tree-structured, then the Chow-Liu algorithm with the plug-in estimator for mutual information with eO (|Σ| …

Generalist Bird Exhibits Site-Dependent Resource Selection, Samantha M. Cady, Craig A. Davis, Samuel D. Fuhlendorf, Rheinhardt Scholtz, Daniel R. Uden, Dirac Twidwell

Department of Agronomy and Horticulture: Faculty Publications

Quantifying resource selection (an organism's disproportionate use of available resources) is essential to infer habitat requirements of a species, develop management recommendations, predict species responses to changing conditions, and improve our understanding of the processes that underlie ecological patterns. Because study sites, even within the same region, can differ in both the amount and the arrangement of cover types, our objective was to determine whether proximal sites can yield markedly different resource selection results for a generalist bird, northern bobwhite (Colinus virginianus). We used 5 years of telemetry locations and newly developed land cover data at two, geographically distinct but …

Reduced-Order Modeling Of Loosening In Bolted Joints And Dynamic Interactions Between Axially Aligned Threaded Joints, Sandro Aldana

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Maintaining effective preload in bolted joints is critical for ensuring long-term performance and safety throughout the operation of any assembled structure. The loosening of bolted joints has been studied since the Industrial Revolution, but modeling approaches have only emerged over the past three decades. Although existing approaches are capable of simulating or predicting loosening in a single joint consisting of a single bolt, they are too computationally expensive to be used to model loosening in large structures consisting of many bolts. The objective of this thesis is to construct and employ a reduced-order modeling (ROM) approach that treats the internal …

An Efficient Multi-Message And Multi-Receiver Signcryption Scheme For Heterogeneous Smart Mobile Iot, Jianying Qiu, Kai Fan, Kuan Zhang, Qiang Pan, Hui Li, Yintang Yang

Department of Electrical and Computer Engineering: Faculty Publications

The Internet of Things (IoT) is developing towards smart and mobile Internet of Things (SM-IoT), which has made great progress. Due to the inherent heterogeneity, distribution, intensive communication, and resource constraints of SM-IoT, efficient security and privacy communication protocols become a particularly critical challenge. Signcryption has received considerable attention. Various signcryption schemes have been proposed to solve secure communication. However, most of them are low in efficiency, without the consideration of characteristics of the SM-IoT. In this paper, we propose a signcryption scheme to achieve efficient secure multi-message and multi-receiver communication for the heterogeneous and distributed SM-IoT. We develop Identity-based …