Engineering Commons^™

What Does It Mean To Be “Prepared For Work”? Perceptions Of New Engineers, Jessica R. Deters, Marie C. Paretti, Logan A. Perry, Robin Ott

Department of Mechanical and Materials Engineering: Faculty Publications

Background: Engineering education seeks to prepare students for engineering practice, but the concept of preparedness is often ill-defined. Moreover, findings from studies of different populations or in different contexts vary regarding how well new graduates are prepared. These variations, coupled with the lack of clarity, suggest the need to better understand what it means to be prepared for engineering work.

Purpose: This study contributes to research on workplace preparation by exploring how new graduates describe being prepared for engineering work.

Method: Applying secondary analysis to data from the multi-institution Capstone To Work (C2W) project, we used thematic …

Integrated Flood Risk Assessment Of Properties And Associated Population At County Scale For Nebraska, Usa, Shivendra Srivastava, Tirthankar Roy

Department of Civil and Environmental Engineering: Faculty Publications

Risk assessment of properties and associated population was conducted for the state of Nebraska, leveraging only open-source datasets. The flood risk framework consisted of interactions among drivers, i.e. hazard, exposure, vulnerability, and response, to assess the risks related to properties and associated populations. To quantify hazard on a county scale, we considered properties at risk of flooding based on a flood score (a higher score represents a greater chance of flooding). Exposure was quantified by considering population density at the county level. We quantified vulnerability under four categories: social, ecological, economic, and health. Response, a relatively newer component in flood …

Integrated Flood Risk Assessment Of Properties And Associated Population At County Scale For Nebraska, Usa, Shivendra Srivastava, Tirthankar Roy

Department of Civil and Environmental Engineering: Faculty Publications

Risk assessment of properties and associated population was conducted for the state of Nebraska, leveraging only open-source datasets. The flood risk framework consisted of interactions among drivers, i.e. hazard, exposure, vulnerability, and response, to assess the risks related to properties and associated populations. To quantify hazard on a county scale, we considered properties at risk of flooding based on a flood score (a higher score represents a greater chance of flooding). Exposure was quantified by considering population density at the county level. We quantified vulnerability under four categories: social, ecological, economic, and health. Response, a relatively newer component in flood …

Environmental Sustainability Of Small Wastewater Treatment Systems And Pathways For Improvement, Matthew James Thompson

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Wastewater treatment protects society and the environment by reducing pollutants generated from communities prior to discharge into local water bodies. Small water resource recovery facilities (WRRFs) represent the majority of centralized wastewater treatment systems, are resource intensive, and often lack resources needed to evaluate sustainability improvements. The goal of this dissertation was to identify primary sources and drivers of environmental impacts in small WRRFs and exploration of pathways to improve their environmental sustainability.

Case study data collected from small WRRFs in Nebraska was analyzed using environmental life cycle assessment (LCA) to quantify the environmental impact of facilities and existing opportunities. …

Room Temperature Two-Dimensional Electron Gas Scattering Time, Effective Mass, And Mobility Parameters In AlXGa1−XN/Gan Heterostructures (0.07 ≤ X ≤ 0.42), Sean Knight, Steffen Richter, Alexis Papamichail, Philipp Kühne, Nerijus Armakavicius, Shiqi Guo, Axel R. Persson, Vallery Stanishev, Viktor Rindert, Per O. Å. Persson, Plamen P. Paskov, Mathias Schubert, Vanya Darakchieva

Department of Electrical and Computer Engineering: Faculty Publications

Al_xGa_1-xN/GaN high-electron-mobility transistor (HEMT) structures are key components in electronic devices operating at gigahertz or higher frequencies. In order to optimize such HEMT structures, understanding their electronic response at high frequencies and room temperature is required. Here, we present a study of the room temperature free charge carrier properties of the two-dimensional electron gas (2DEG) in HEMT structures with varying Al content in the Al_xGa_1-xN barrier layers between x = 0:07 and x = 0:42. We discuss and compare 2DEG sheet density, mobility, effective mass, sheet resistance, and scattering times, …

Integrative Transcriptomics And Proteomics Profiling Of Arabidopsis Thaliana Elucidates Novel Mechanisms Underlying Spaceflight Adaptation, Gbolaga O. Olanrewaju, Natasha J. Haveman, Michael J. Naldrett, Anna-Lisa Paul, Robert J. Ferl, Sarah E. Wyatt

Nebraska Center for Biotechnology: Faculty and Staff Publications

Spaceflight presents a unique environment with complex stressors, including microgravity and radiation, that can influence plant physiology at molecular levels. Combining transcriptomics and proteomics approaches, this research gives insights into the coordination of transcriptome and proteome in Arabidopsis’ molecular and physiological responses to Spaceflight environmental stress. Arabidopsis seedlings were germinated and grown in microgravity (μg) aboard the International Space Station (ISS) in NASA Biological Research in Canisters – Light Emitting Diode (BRIC LED) hardware, with the ground control established on Earth. At 10 days old, seedlings were frozen in RNA-later and returned to Earth. RNA-seq transcriptomics and TMTlabeled LC-MS/MS proteomic …

Study On Debinding And Sintering Conditions In Extrusion-Based Additive Manufacturing Of 316l And 316l + Cu, Jean-François Silvain, Daniel Lincoln Gifford, Sébastien Fourcade, Laurent Cuzacq, Jean-Luc Grosseau-Poussard, Catherine Debiemme-Chouvy, Nicolas Tessier Doyen, Yongfeng Lu

Department of Electrical and Computer Engineering: Faculty Publications

This study investigates the use of a methylcellulose binder in extrusion additive manufacturing of 316L as an alternative to common wax-based binders. Various quantities of copper (Cu) powder were also added in the paste composition to attempt to reduce the sintering temperature by promoting persistent liquid phase sintering. Debinding experiments were conducted under different temperatures and dwell times using argon (Ar), Ar/5%H₂, and Ar/1%O₂ atmospheres. Debinding reduced carbon (C) content to 0.032 wt.% by using a two-step debinding process of Ar/5%H₂ and Ar/1%O₂ thermal treatments. Using this debinding process, sintering was conducted at 1200 ^{o …}

Organic Electronics In Biosensing: A Promising Frontier For Medical And Environmental Applications, Jyoti Bala Kaushal, Pratima Raut, Sanjay Kumar

Durham School of Architectural Engineering and Construction: Faculty Publications

The promising field of organic electronics has ushered in a new era of biosensing technology, thus offering a promising frontier for applications in both medical diagnostics and environmental monitoring. This review paper provides a comprehensive overview of organic electronics’ remarkable progress and potential in biosensing applications. It explores the multifaceted aspects of organic materials and devices, thereby highlighting their unique advantages, such as flexibility, biocompatibility, and low-cost fabrication. The paper delves into the diverse range of biosensors enabled by organic electronics, including electrochemical, optical, piezoelectric, and thermal sensors, thus showcasing their versatility in detecting biomolecules, pathogens, and environmental pollutants. Furthermore, …

Bridging Domain Gaps For Cross-Spectrum And Long-Range Face Recognition Using Domain Adaptive Machine Learning, Cedric Armel Nimpa Fondje

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Face recognition technology has witnessed significant advancements in recent decades, enabling its widespread adoption in various applications such as security, surveillance, and biometrics applications. However, one of the primary challenges faced by existing face recognition systems is their limited performance when presented with images from different modalities or domains( such as infrared to visible, long range to close range, nighttime to daytime, profile to f rontal, etc.) Additionally, advancements in camera sensors, analytics beyond the visible spectrum, and the increasing size of cross-modal datasets have led to a particular interest in cross-modal learning for face recognition in the biometrics and …

A Multi-Organ Maize Metabolic Model Connects Temperature Stress With Energy Production And Reducing Power Generation, Niaz Bahar Chowdhury, Margaret Simons- Senftle, Berengere Decouard, Isabelle Quillere, Martine Rigault, Karuna Anna Sajeevan, Bibek Acharya, Ratul Chowdhury, Bertrand Hirel, Alia Dellagi, Costas Maranas, Rajib Saha

Department of Chemical and Biomolecular Engineering: Faculty Publications

Climate change has adversely affected maize productivity. Thereby, a holistic understanding of metabolic crosstalk among its organs is important to address this issue. Thus, we reconstructed the first multi-organ maize metabolicmodel, iZMA6517, and contextualized itwith heat and cold stress transcriptomics data using expression distributed reaction flux measurement (EXTREAM) algorithm. Furthermore, implementing metabolic bottleneck analysis on contextualized models revealed differences between these stresses. While both stresses had reducing power bottlenecks, heat stress had additional energy generation bottlenecks.We also performed thermodynamic driving force analysis, revealing thermodynamics-reducing power-energy generation axis dictating the nature of temperature stress responses. Thus, a temperaturetolerant maize ideotype can …

Transportation Components Of The City Of Bennet Comprehensive Plan And Downtown Economic Development Plan, Kyle Mclaughlin

Community and Regional Planning Program: Theses

In partnership with the City of Bennet, the University of Nebraska, and Marvin Planning Consultants, this project assisted the creation of the City’s Comprehensive Plan and Downtown Economic Development Plan by creating a transportation focused report as a supplement to those plans. The project operates in six sections; Introduction and Overview, Evaluate the Present, Engage the Community, Recommendations, Strategies, and Policies, Implementation and Funding, and Monitoring and Evaluation. The project scope included existing conditions understanding, qualitative and quantitative transportation analysis, public engagement and stakeholder meetings, coordination with two plan creators, identifying transportation improvements, description of implementation steps, overview of available …

Motif-Cluster: A Spatial Clustering Package For Repetitive Motif Binding Patterns, Mengyuan Zhou

School of Computing: Dissertations, Theses, and Student Research

Previous efforts in using genome-wide analysis of transcription factor binding sites (TFBSs) have overlooked the importance of ranking potential significant regulatory regions, especially those with repetitive binding within a local region. Identifying these homogenous binding sites is critical because they have the potential to amplify the binding affinity and regulation activity of transcription factors, impacting gene expression and cellular functions. To address this issue, we developed an open-source tool Motif-Cluster that prioritizes and visualizes transcription factor regulatory regions by incorporating the idea of local motif clusters. Motif-Cluster can rank the significant transcription factor regulatory regions without the need for experimental …

Biomimetic Approach To Elucidate The Role Of Microenvironment In Regulating Cell Communications In Liver Diseases, Youra Moeun

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Liver is a complex organ but often underappreciated for its functions to remove toxins and fight infection in the body. Despite the ongoing prevalence of patients contracting chronic liver diseases, coupled with a global healthcare investment of approximately $70 billion, there is still no effective treatment for chronic liver diseases including alcoholic liver disease. The purpose of this dissertation was to understand the interactions of parenchymal and non-parenchymal liver cells in physiological and pathological like environments. This allowed us to recreate a healthy and the diseased microenvironments to observe the stages of the liver diseases development and apply appropriate treatments …

Modeling Overdraft-Driven Nitrate Transport In Shallow Wells For Mitigation And Scenario Planning, Jonathan Cronk

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

In Nebraska, average nitrate concentrations in groundwater have doubled since 1974, making water quality management more important than ever. As droughts, heat waves, and floods become more common climate events, understanding their impacts will be necessary to make informed management decisions. Emerging literature describes that drought correlates to an increase in the concentration of nitrate-N at domestic and irrigation wells, however the relative contributions of the mechanisms thought to be responsible is currently unknown.

This research assessed the impact of recharge and pumping rate changes as two mechanisms affecting nitrate-N concentration during drought, assessed the relationship between well depth and …

Meta-Analysis Of Insulated Concrete Wall Panel Design Methods For Shear And Flexure Behavior, Maryam Al-Bayati

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

Insulated Concrete wall panels have been designed and constructed since the early 1950s with various shear ties, dimensions, and methods; nonetheless, thermal bridging and rational design are still a concern. Many companies have recently developed plastic connectors that have gradually replaced solid concrete sections and steel connectors due to their superior thermal efficiency and strength. However, there is no generally accepted method for predicting the behavior of sandwich wall panels in structural engineering practice or codes, but many methods have been used since the early 1920. This study aims to evaluate the accuracy of current methods for predicting the flexural …

Continuous Time Recurrent Network For Human Activity Detection, Abdallah Al Zubi

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

Human activity detection is crucial to personalize the control of the building environment. For example, understanding certain human activities (e.g., walking, sitting, etc.) for an occupant in a building helps provide the proper thermal comfort control. However, these applications require large-scale neural networks that are challenging to implement and train.

In this thesis, we implemented a continuous-time recurrent neural network implementation (CTRNN) network that can solve real-time human activity detection with a smaller-size network. The CTRNN uses differential equations with a time constant to describe the neuron equations. It was implemented and trained for the first time using TensorFlow. Specifically, …

Analysis Of Bombyx Mori Silk And Polyimide Nanofibers, Sabrina Leseul

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

This thesis presents a study on the properties of Bombyx Mori silk nanofibers and polyimide (PI) nanofibers. Firstly, a Bombyx Mori silk solution has been created with degummed silkworm cocoons in order to separate the fibroin and the sericin, the two main proteins of the silk. The fibroin was then centrifuged to remove insoluble particles and stored and 4°C before mixing with hexafluoroisopropanol (HFIP). On the second part, a polyimide solution, made with shavings of polyimide and N,N-dimethylformamide (DMF). Both solutions are then electrospun. Electrospinning parameters are studied. In this way, a part of my thesis has been dedicated to …

Hydroxyapatite-Based Coatings On Silicon Wafers And Printed Zirconia, Antoine Chauvin

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

Dental surgery needs a naturally attract implant design that can ensure both osseointegration and soft tissue integration. Hydroxyapatite (HAp), the main mineral constituent of dentine and tooth enamel, is commonly used as a coating component, notably for overlaying titanium– or ceramics–based implants. This thesis aims to investigate the behavior of a HAp-based coating, specifically designed to be compatible with a porous substrate. Coating layers are made by sol–gel dip coating by immersion of porous substrates made by additive manufacturing into solutions of HAp, having been mixed with polyethyleneimine (PEI), to improve the adhesion of HAp on the substrate. First, the …

Applications Of Femtosecond Laser-Processed And Nanoneedle-Synthesized Surfaces To Enhance Pool Boiling Heat Transfer, Peter Efosa Ohenhen

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

In the present work, the integration of femtosecond laser surface processing (FLSP) with copper hydroxide on hybrid surfaces was examined. The goal was to determine the impact on pool boiling enhancement. The samples for the investigation were fabricated by first functionalizing with FLSP, and the process was then followed by citric acid cleaning (CAC) to eliminate the oxides generated on the copper surface during the FLSP process. After the citric acid cleaning, the samples were immersed in ethanol and subjected to an ultrasonic bath for 25 minutes. This step was performed to eliminate any residual citric acid and loose particles. …

A Generalized Machine Learning-Based Classifier Considering Cost-Effective Features For Automated Fault Detection And Diagnosis (Afdd) Of Packaged Rooftop Units, Md Rasel Uddin

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Packaged rooftop units (RTUs) are widely used for space conditioning in commercial buildings and manufacturing facilities. The typical soft faults related to RTUs degrade the system's performance in terms of cooling capacity, power consumption, and Coefficient of Performance (COP), detrimentally affecting both the equipment and energy consumption and the environment. Previous research in soft fault detection for rooftop units lacked classifier validation using lab and field data, developing a generalizable algorithm, and analyzing its performance across varying fault intensities.

Using a simulated data library for multiple rooftop units, this study proposes a machine-learning classifier with a reduced set of 9 …

A Review On The Coalescence Of Confined Drops With A Focus On Scaling Laws For The Growth Of The Liquid Bridge, Sangjin Ryu, Haipeng Zhang, Udochukwu John Anuta

Department of Mechanical and Materials Engineering: Faculty Publications

The surface–tension-driven coalescence of drops has been extensively studied because of the omnipresence of the phenomenon and its significance in various natural and engineering systems. When two drops come into contact, a liquid bridge is formed between them and then grows in its lateral dimensions. As a result, the two drops merge to become a bigger drop. The growth dynamics of the bridge are governed by a balance between the driving force and the viscous and inertial resistances of involved liquids, and it is usually represented by power–law scaling relations on the temporal evolution of the bridge dimension. Such scaling …

Revealing Interface-Assisted Plastic Anisotropy Via In Situ Transmission Electron Microscopy Tension Of Lamellar Tial, Zhixiang Qi, Qi Zhu, Jian Wang, Yuede Cao, Fengrui Chen, Jiangwei Wang, Yang Chen, Gong Zheng, Guang Chen

Department of Mechanical and Materials Engineering: Faculty Publications

Assembling functional units into specific orientation organizations based on functional unit and organization (FUO) paradigm can maximize utilizing mechanical property anisotropy of lamellar-structured materials. However, the origin of their anisotropic deformation behaviors has not been clearly understood. Taking the fully lamellar γ-TiAl/ α₂-Ti₃Al dual-phase single crystal as an example, we decouple the interface functional units governed anisotropic plastic deformation through in situ transmission electron microscopy tensile testing and multiscale microstructural characterizations. The orientation organization-dependent slip continuity across the γ/α₂ interface and interface strength play a determinant role in plastic anisotropy beyond intrinsic dislocation activities within …

Executive Order On The Safe, Secure, And Trustworthy Development And Use Of Artificial Intelligence, Joseph R. Biden

Copyright, Fair Use, Scholarly Communication, etc.

Section 1. Purpose. Artificial intelligence (AI) holds extraordinary potential for both promise and peril. Responsible AI use has the potential to help solve urgent challenges while making our world more prosperous, productive, innovative, and secure. At the same time, irresponsible use could exacerbate societal harms such as fraud, discrimination, bias, and disinformation; displace and disempower workers; stifle competition; and pose risks to national security. Harnessing AI for good and realizing its myriad benefits requires mitigating its substantial risks. This endeavor demands a society-wide effort that includes government, the private sector, academia, and civil society.

My Administration places the highest urgency …

A Critical Review Of Risk Matrices Used In Water Safety Planning: Improving Risk Matrix Construction, Kaycie Lane, Steve E. Hrudey

Department of Civil and Environmental Engineering: Faculty Publications

Risk matrices are used in water safety planning to prioritize improvements to drinking water systems. While water safety plans (WSPs) are promoted globally, no study has evaluated whether risk matrices are comprehensively constructed to accurately assess risk. We used risk matrix criteria adapted from previous risk matrix research to evaluate risk matrices found in twelve templates across global jurisdictions. WSP templates were found using the WSPortal website and definitions of likelihood and impact were extracted from each template to assist in the evaluation of WSP risk matrices. Application of the criteria developed from a detailed mathematical analysis by revealed that …

Examining The Corn Seedling Emergence–Temperature Relationship For Recent Hybrids: Insights From Experimental Studies, Sahila Beegum, Charles Hunt Walne, Krishna N. Reddy, Vangimalla Reddy, Kambham Raja Reddy

Nebraska Water Center: Faculty Publications

Corn seedling emergence is a critical factor affecting crop yields. Accurately predicting emergence is crucial for precise crop growth and development simulation in process-based crop models. While various experimental studies have investigated the relationship between corn seedling emergence and temperature, there remains a scarcity of studies focused on newer corn hybrids. In the present study, statistical models (linear and quadratic functional relationships) are developed based on the seedling emergence of ten current corn hybrids, considering soil and air temperatures as influencing factors. The data used for model development are obtained from controlled soil plant atmospheric research chamber experiments focused on …

A Text Analytics Model For Agricultural Knowledge Discovery And Sustainable Food Production: A Case Study From Oklahoma Panhandle, Ali Bagheri, Saleh Taghvaeian, Dursun Delen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

With recent increases in the use of social media in agricultural communities, many farmers are showing more and more interest in participating in social media and sharing different aspects of their profession with peers and policymakers. However, researchers have not explored this valuable data source well enough to help improve agribusiness decision-making. This study aims to investigate the potential capability and richness of social media for agricultural knowledge discovery, which can help monitor, detect, and predict critical agricultural events and activities and develop more sustainable food production and agricultural economy. This research utilizes text-mining tools and techniques to collect, process, …

Analysis Of Wastewater Samples To Explore Community Substance Use In The United States: Pilot Correlative And Machine Learning Study, Marie A. Severson, Sathaporn Onanong, Alexandra Dolezal, Shannon L. Bartelt-Hunt, Daniel D. Snow, Lisa M. Mcfadden

Nebraska Water Center: Faculty Publications

Background: Substance use disorder and associated deaths have increased in the United States, but methods for detecting and monitoring substance use using rapid and unbiased techniques are lacking. Wastewater-based surveillance is a cost-effective method for monitoring community drug use. However, the examination of the results often focuses on descriptive analysis.

Objective: The objective of this study was to explore community substance use in the United States by analyzing wastewater samples. Geographic differences and commonalities of substance use were explored.

Methods: Wastewater was sampled across the United States (n=12). Selected drugs with misuse potential, prescriptions, and over-the-counter drugs …

Statistical And Machine Learning Approaches To Describe Factors Affecting Preweaning Mortality Of Piglets, Md Towfiqur Rahman, Tami M. Brown-Brandl, Gary A. Rohrer, Sudhendu R. Sharma, Vamsi Manthena, Yeyin Shi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

High preweaning mortality (PWM) rates for piglets are a significant concern for the worldwide pork industries, causing economic loss and well-being issues. This study focused on identifying the factors affecting PWM, overlays, and predicting PWM using historical production data with statistical and machine learning models. Data were collected from 1,982 litters from the United States Meat Animal Research Center, Nebraska, over the years 2016 to 2021. Sows were housed in a farrowing building with three rooms, each with 20 farrowing crates, and taken care of by well-trained animal caretakers. A generalized linear model was used to analyze the various sow, …

Breakdown Of The Drift-Diffusion Model For Transverse Spin Transport In A Disordered Pt Film, Kirill D. Belashchenko, Giovanni G. Baez Flores, Wuzhang Fang, Alexey Kovalev, Mark Van Schilfgaarde, Paul M. Haney, Mark D. Stiles

Department of Physics and Astronomy: Faculty Publications

Spin-accumulation and spin-current profiles are calculated for a disordered Pt film subjected to an in-plane electric current within the nonequilibrium Green's function approach. In the bulklike region of the sample, this approach captures the intrinsic spin Hall effect found in other calculations. Near the surfaces, the results reveal qualitative differences with the results of the widely used spin-diffusion model, even when the boundary conditions are modified to try to account for them. One difference is that the effective spin-diffusion length for transverse spin transport is significantly different from its longitudinal counterpart and is instead similar to the mean-free path. This …

Evaluation Of Equivalent Thermal Conductivity For Carbon Fiber-Reinforced Bentonite Through Experimental And Numerical Analysis, Yuan Feng, Jongwan Eun, Seunghee Kim, Yong-Rak Kim

Department of Civil and Environmental Engineering: Faculty Publications

Bentonite is widely used as a water-proof material in engineering, and fibers are added to reduce the crack development of bentonite after drying. Carbon fiber can reinforce bentonite in heat-sensitive projects because of its high thermal conductivity and potential inhibition of bentonite cracking. Thus, it is important to determine the thermal conductivity of carbon fiber-reinforced bentonite. This study evaluated the thermal conductivity of carbon fiber-reinforced bentonite by analytical solution, experiment, and finite element method (FEM) simulation and discussed the effects of carbon fiber content, fiber length, fiber distribution, and the porosity of bentonite on the thermal conductivity of reinforced bentonite. …