Engineering Commons^™

Digitally Twinned Additive Manufacturing: Detecting Flaws In Laser Powder Bed Fusion By Combining Thermal Simulations With In-Situmeltpool Sensor Data, R Yavari, A Riensche, E Tekerek, L Jacquemetton, H Halliday, M Vandever, A Tenequer, V Perumal, A Kontsos, Z Smoqi, K Cole, P Rao

Department of Mechanical and Materials Engineering: Faculty Publications

The goal of this research is the in-situ detection of flaw formation in metal parts made using the laser powder bed fusion (LPBF) additive manufacturing process. This is an important area of research, because, despite the considerable cost and time savings achieved, precision-driven industries, such as aerospace and biomedical, are reticent in using LPBF to make safety–critical parts due to tendency of the process to create flaws. Another emerging concern in LPBF, and additive manufacturing in general, is related to cyber security – malicious actors may tamper with the process or plant flaws inside a part to compromise its performance. …

Use Of Average Mutual Information And Derived Measures To Find Coding Regions, Garin Newcomb, Khalid Sayood

Department of Electrical and Computer Engineering: Faculty Publications

One of the important steps in the annotation of genomes is the identification of regions in the genome which code for proteins. One of the tools used by most annotation approaches is the use of signals extracted from genomic regions that can be used to identify whether the region is a protein coding region. Motivated by the fact that these regions are information bearing structures we propose signals based on measures motivated by the average mutual information for use in this task. We show that these signals can be used to identify coding and noncoding sequences with high accuracy. We …

Defining The Innate Immune Responses For Sars-Cov-2-Human Macrophage Interactions, Mai M. Abdelmoaty, Pravin Yeapuri, Jatin Machhi, Katherine E. Olson, Farah Shahjin, Vikas Kumar, You Zhou, Jingjing Liang, Kabita Pandey, Arpan Acharya, Siddappa N. Byrareddy, R. Lee Mosley, Howard E. Gendelman

Nebraska Center for Biotechnology: Faculty and Staff Publications

Host innate immune response follows severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and it is the driver of the acute respiratory distress syndrome (ARDS) amongst other inflammatory end-organ morbidities. Such life-threatening coronavirus disease 2019 (COVID-19) is heralded by virus-induced activation of mononuclear phagocytes (MPs; monocytes, macrophages, and dendritic cells). MPs play substantial roles in aberrant immune secretory activities affecting profound systemic inflammation and end-organ malfunctions. All follow the presence of persistent viral components and virions without evidence of viral replication. To elucidate SARS-CoV- 2-MP interactions we investigated transcriptomic and proteomic profiles of human monocyte-derived macrophages. While expression of the …

Near-Field Imaging Of Plasmonic Nanopatch Antennas With Integrated Semiconductor Quantum Dots, Vasudevan Iyer, Yoong Sheng Phang, Andrew Butler, Jiyang Chen, Brian Lerner, Christos Argyropoulos, Thang Hoang, Benjamin Lawrie

Department of Electrical and Computer Engineering: Faculty Publications

Plasmonic nanopatch antennas that incorporate dielectric gaps hundreds of picometers to several nanometers thick have drawn increasing attention over the past decade because they confine electromagnetic fields to grossly sub-diffraction-limited volumes. Substantial control over the optical properties of excitons and color centers confined within these plasmonic cavities has already been demonstrated with far-field optical spectroscopies, but near-field optical spectroscopies are essential for an improved understanding of the plasmon–emitter interaction at the nanoscale. Here, we characterize the intensity and phase-resolved plasmonic response of isolated nanopatch antennas by cathodoluminescence microscopy. Furthermore, we explore the distinction between optical and electron beam spectroscopies of …

Association Between Aqueous Atrazine And Pediatric Cancer In Nebraska, Jagadeesh Puvvula, Shannon L. Bartelt-Hunt, Balkiss S. Ouattara, Alan S. Kolok, Jesse E. Bell, Eleanor G. Rogan

Department of Civil and Environmental Engineering: Faculty Publications

Agrichemicals, chemicals used to maximize crop and animal production, can lead to water quality concerns when these chemicals run off into surface and groundwater after precipitation events. In Nebraska, one such chemical is atrazine, a suspected carcinogen. This study evaluated the association between atrazine in surface and groundwater, in relation to the incidence of pediatric cancer in Nebraska watersheds over 30 years (1 January 1987 to 31 December 2016). The watersheds were grouped into four categories based on the average atrazine concentration over the study period, using quantile classification. The associations between atrazine (ground/surface) and pediatric cancer after adjusting for …

Greenhouse Gas Emissions And Drought Projections For Nebraska, Adam Liska

Adam Liska Papers

This lecture will focus on three issues. The first is a presentation of data from the first greenhouse gas emissions inventory for the State of Nebraska, which will be published in the coming weeks. In 2016, emissions from beef cattle made up 23% of net state emissions, and coal for electricity made up 23.7% of net state emissions. The second issue to be addressed are the impacts of the 2012 drought on agriculture in Nebraska and the region. The drought of 2012 indicates that future droughts in the 21^st century in the region can be a dominant influence on …

Crest Or Trough? How Research Libraries Used Emerging Technologies To Survive The Pandemic, So Far, Scout Calvert

University of Nebraska-Lincoln Libraries: Faculty Publications

Introduction

In the first months of the COVID-19 pandemic, it was impossible to tell if we were at the crest of a wave of new transmissions, or a trough of a much larger wave, still yet to peak. As of this writing, as colleges and universities prepare for mostly in-person fall 2021 semesters, case counts in the United States are increasing again after a decline that coincided with easier access to the COVID vaccine. Plans for a return to campus made with confidence this spring may be in doubt, as we climb the curve of what is already the second …

Recent Updates On Ions And Nutrients Uptake By Halotolerant Freshwater And Marine Microalgae In Conditions Of High Salinity, Abdul Mannan Zafar, Muhammad Asad Javed, Ashraf Aly Hassan, Khalid Mehmood, Endalkachew Sahle-Demessie

Department of Civil and Environmental Engineering: Faculty Publications

Algae is an appropriate natural resource to augment the optimal use of undesired ions in water and wastewater. Increasing algal cells, the consumption of particular ions, including chloride, nitrate, phosphate, and ammonium, provides a suitable way to optimize water treatment processes. Different algal species have the capability to survive in extreme salinities by developing resistance against osmotic pressure in saline water. The current study reviews the effect of salinity on algal biomass production, algal growth rate, chlorides, nitrates, phosphates, chemical oxygen demand (COD), total nitrogen, total phosphorus, and ammonium ions. Mainly algae cultivated in freshwater, synthetic brackish water, seawater, and …

Inter-Relationships Between Water Depletion And Temperature Differential In Row Crop Canopies In A Sub-Humid Climate, Jasreman Singh, Yufeng Ge, Derek M. Heeren, Elizabeth Walter-Shea, Christopher M.U. Neale, Suat Irmak, Wayne Woldt, Geng Bai, Sandeep Bhatti, Mitchell S. Maguire

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Irrigation has a great impact on global food security as it contributes to the majority of the world’s agricultural food supply. It is essential to judiciously utilize water resources through efficient irrigation management since the majority of U.S. groundwater aquifers are rapidly depleting. Thus, quantification of the relationships between water depletion and environmental factors is important for understanding crop response to varying levels of water stresses that depletion can cause. The objectives of this research were to: 1) investigate the relationship between root zone water depletion (D_rw) and canopy temperature differential (ΔT) at different ranges of D_{rw …}

Https://Dot.Nebraska.Gov/Media/4yaemfil/M100-Nebraska-Buried-Archeological-Sites-Phase-Ii.Pdf, Anthony L. Layzell, Rolfe D. Mandel, Courtney L. Ziska, John R. Bozell

Nebraska Department of Transportation: Research Reports

This project developed a GIS to assist with the identification of deeply buried archeological sites in alluvial settings across Nebraska with the exception of the Sandhills region. Soil survey data, previous geoarcheological investigations, landform position, and other information was used to rank the potential of any stream valley setting as low, low-moderate, moderate-high, or high potential to contain buried soils (paleosols). While the presence of buried soils does not necessarily translate to presence of buried archeological sites, the potential for such sites is far greater in paleosols. The GIS can be used by NDOT and other agencies with statutory historic …

Hybrid Scenario Generation Method For Stochastic Virtual Bidding In Electricity Market, Dongliang Xiao,, Wei Qiao

Department of Electrical and Computer Engineering: Faculty Publications

Stochastic optimization can be used to generate optimal bidding strategies for virtual bidders in which the uncertain electricity prices are represented by using scenarios. This paper proposes a hybrid scenario generation method for electricity price using a seasonal autoregressive integrated moving average (SARIMA) model and historical data. The electricity price spikes are first identified by using an outlier detection method. Then, the historical data are decomposed into base and spike components. Next, the base and spike component scenarios are generated by using the SARIMA- and historical data-based methods, respectively. Finally, the electricity price scenarios are obtained by combining the base …

Unconventional Van Der Waals Heterostructures Beyond Stacking, Peter Sutter, Eli A. Sutter

Department of Electrical and Computer Engineering: Faculty Publications

Two-dimensional crystals provide exceptional opportunities for integrating dissimilar materials and forming interfaces where distinct properties and phenomena emerge. To date, research has focused on two basic heterostructure types: vertical van der Waals stacks and laterally joined monolayer crystals with in-plane line interfaces. Much more diverse architectures and interface configurations can be realized in the few-layer and multilayer regime, and if mechanical stacking and single-layer growth are replaced by processes taking advantage of self-organization, conversions between polymorphs, phase separation, strain effects, and shaping into the third dimension. Here, we highlight such opportunities for engineering heterostructures, focusing on group IV chalcogenides, a …

Simulation For A Mems-Based Ctrnn Ultra-Low Power Implementation Of Human Activity Recognition, Muhammad Emad-Ud-Din, Mohammad H. Hasan, Roozbeh Jafari, Siavash Pourkamali, Fadi M. Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper presents an energy-efficient classification framework that performs human activity recognition (HAR). Typically, HAR classification tasks require a computational platform that includes a processor and memory along with sensors and their interfaces, all of which consume significant power. The presented framework employs microelectromechanical systems (MEMS) based Continuous Time Recurrent Neural Network (CTRNN) to performHAR tasks very efficiently. In a real physical implementation, we show that the MEMS-CTRNN nodes can perform computing while consuming power on a nano-watts scale compared to the micro-watts state-of-the-art hardware. We also confirm that this huge power reduction doesn’t come at the expense of reduced …

Characterization Of Tea (Camellia Sinensis) Granules For Quality Grading Using Computer Vision System, Md Towfiqur Rahman, Sabiha Ferdous, Mariya Sultana Jenin, Tanjina Rahman Mim, Masud Alam, Muhammad Rashed Al Mamun

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Tea (Camellia sinensis) has been found as an important medicinal beverage for human which is consumed all over the world. Primarily, the majority of tea is being cultivated in Asia and Africa, however it is commercially produced by more than 60 countries. Though substantial amount is produced, its processing system is still underdeveloped which leads to decrease in export opportunity as well as low monetary value. Moreover, the traditional method of tea grading and sorting is laborious, inefficient, and costly which ultimately produces the low-quality heterogeneous products. Processing and grading of tea granules after drying is very important …

Assessment Of A Program For Sars-Cov-2 Screening And Environmental Monitoring In An Urban Public School District, John Crowe, Andy T. Schnaubelt, Scott Schmdit Bonne, Kathleen Angell, Julia Bai, Teresa Eske, Molly Nicklin, Catherine Pratt, Bailey White, Brodie Crotts-Hannibal, Nicholas Staffend, Vicki Herrera, Jeramie Cobb, Jennifer Connor, Julie Carstens, Jonell Tempero, Lori Bouda, Matthew Ray, James V. Lawler, W Scott Campbell, John-Martin Lowe, Joshua Santarpia, Shannon Bartelt-Hunt, Michael Wiley, David Brett-Major, Cheryl Logan, Jana Broadhurst

Department of Civil and Environmental Engineering: Faculty Publications

IMPORTANCE Scalable programs for school-based SARS-CoV-2 testing and surveillance are needed to guide in-person learning practices and inform risk assessments in kindergarten through 12th grade settings. OBJECTIVES To characterize SARS-CoV-2 infections in staff and students in an urban public school setting and evaluate test-based strategies to support ongoing risk assessment and mitigation for kindergarten through 12th grade in-person learning. DESIGN, SETTING, AND PARTICIPANTS This pilot quality improvement program engaged 3 schools in Omaha, Nebraska, for weekly saliva polymerase chain reaction testing of staff and students participating in in-person learning over a 5-week period from November 9 to December 11, 2020. …

Framework To Develop Time- And Voltage-Dependent Building Load Profiles Using Polynomial Load Models, Andrew Parker, Mhd Anas Alkrch, Kevin James, Ahmad Almaghrebi, Mahmoud Alahmad

Durham School of Architectural Engineering and Construction: Faculty Publications

The power consumption of buildings over the course of each minute, hour, day and season plays a major role in how this load influences the Electric Power System voltage and frequency, and vice versa. This consumption is based on the building's load component types, efficiencies, and how they consume power and react to changes in real time. Due to this complexity, standard full-building load models are typically voltage-invariant. This paper proposes a novel framework to transform these voltage-invariant building load models into fully time- and voltage-dependent load profiles using available data on the voltage sensitivity of individual load components. While …

A Case Study To Quantify Variability In Building Load Profiles, Andrew Parker, Sam Moayedi, Kevin James, Dongming Peng, Mahmoud Alahmad

Durham School of Architectural Engineering and Construction: Faculty Publications

Recent technology development and penetration of advanced metering infrastructure (AMI), advanced building control systems, and the internet-of-things (IoT) in the built environment are providing detailed information on building operation, performance, and user's comfort and behavior. Building owners can obtain a wide range of energy consumption details at various levels of time granularity to augment their decisions as they manage the building operation and interact with the grid. AMI data are providing a new level of detail and visibility that may enhance building services and assets in the smart grid domain and make buildings inch closer to becoming a grid-interactive energy …

Pollution Prevention/Environmental Sustainability For Industry, Bruce Dvorak

Department of Civil and Environmental Engineering: Faculty Publications

It has been 30 years since, in the United States, the Pollution Prevention Act of 1990 focused attention on reducing pollution through cost-effective changes in production, operation, and raw materials use. The pollution prevention approach was novel in focusing on increasing the efficiency of a process and reducing the amount of pollution generated at its source. Worldwide, industrial organizations embraced cleaner production approaches that result in reducing pollution at the source. Governmental bodies are exploring the best prevention and control polices for pollution and energy management. Since that time, the industry has successfully applied the three pillars of sustainability—economic, environmental, …

Exploring The Structural Uniformity And Integrity Of Protonic Ceramic Thin Film Electrolyte Using Wet Powder Spraying, Wuxiang Feng, Wei Wu, Congrui Grace Jin, Meng Zhou, Wenjuan Bian, Wei Tang, Joshua Y. Gomez, Richard Boardman, Dong Ding

Department of Civil and Environmental Engineering: Faculty Publications

Thin protonic ceramic electrolyte contributes to lower ohmic resistance and enhances electrochemical performance of protonic ceramic electrochemical cells. However, manufacturing of large-scale thin electrolyte remains a challenge. Wet powder spraying is an attractive technique to deposit <10 >μm thin electrolyte when advanced atomizing techniques and optimized spraying process are integrated. Here ultrasonic atomization is integrated in the wet powder spray technique to reduce the thickness of electrolyte. Moreover, a parametric study is conducted to optimize the wet powder spray process to deposit uniform and crack-free electrolyte film. It is illustrated that tuning of solid loading rates and spray passes can affect …

High-Frequency And Below Bandgap Anisotropic Dielectric Constants In Α-(AlXGa1-X)2O3 (0≤X≤1), Matthew Hilfiker, Ufuk Kilic, Megan Stokey, Riena Jinno, Yongjin Cho, Huili Grace Xing, Debdeep Jena, Rafal Korlacki, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

A Mueller matrix spectroscopic ellipsometry approach was used to investigate the anisotropic dielectric constants of corundum α-(Al_xGa_1-x)₂O₃ thin films in their below bandgap spectral regions. The sample set was epitaxially grown using plasma-assisted molecular beam epitaxy on m-plane sapphire. The spectroscopic ellipsometry measurements were performed at multiple azimuthal angles to resolve the uniaxial dielectric properties. A Cauchy dispersion model was applied, and high-frequency dielectric constants are determined for polarization perpendicular (ε_∞,⟂) and parallel (ε_∞,∥) to the thin film c-axis. The optical birefringence is negative throughout the …

Validation Of The Mathematics Motivation Questionnaire (Mmq) For Secondary School Students, Logan Fiorella, So Yoon Yoon, Kinnari Atit, Jason R. Power, Grace Panther, Sheryl Sorby, David H. Uttal, Norma Veurink

Department of Civil and Environmental Engineering: Faculty Publications

Background: Motivation is critical for supporting persistence and achievement in science, technology, engineering, and mathematics (STEM) disciplines. In this study, we focus on the assessment of mathematics motivation among secondary school students. We provide validity and reliability evidence for the Mathematics Motivation Questionnaire (MMQ)—adapted from the Science Motivation Questionnaire designed for college students—using data from 2551 secondary students from seven states across the United States. Results: Exploratory and confirmatory factor analyses confirmed five latent factors of the MMQ indicated by 19 items: intrinsic value, self-regulation, self-efficacy, utility value, and test anxiety. The nonlinear SEM reliability coefficients of the five constructs …

Contact Angle Measurement Using A Hele-Shaw Cell: A Proof-Of-Concept Study, Haipeng Zhang, Jacob Gottberg, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Contact angle is an important property to quantify the wettability of a solid surface with a liquid, which characterizes interactions of the solid-liquid pair. Generally, to measure contact angle, special instruments such as a goniometer are necessary, but they are not readily available in certain research settings. In this study, an alternative method to measure contact angle based on a Hele-Shaw cell, microscopy imaging, and image processing is suggested. In this method, a liquid drop is injected into a transparent Hele-Shaw cell, the meniscus of the drop is captured in the top or bottom view using a brightfield microscope, and …

Contact Angle Measurement Using A Hele-Shaw Cell: A Proof-Of-Concept Study, Haipeng Zhang, Jacob Gottberg, Sangjin Ryu

Department of Mechanical and Materials Engineering: Faculty Publications

Contact angle is an important property to quantify the wettability of a solid surface with a liquid, which characterizes interactions of the solid-liquid pair. Generally, to measure contact angle, special instruments such as a goniometer are necessary, but they are not readily available in certain research settings. In this study, an alternative method to measure contact angle based on a Hele-Shaw cell, microscopy imaging, and image processing is suggested. In this method, a liquid drop is injected into a transparent Hele-Shaw cell, the meniscus of the drop is captured in the top or bottom view using a brightfield microscope, and …

Disturbance Triggers Non-Linear Microbe–Environment Feedbacks, Aditi Sengupta, Sarah J. Fansler, Rosalie K. Chu, Robert E. Danczak, Vanessa A. Garayburu-Caruso, Lupita Renteria, Hyun-Seob Song, Jason Toyoda, Jacqueline Wells, James C. Stegen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Conceptual frameworks linking microbial community membership, properties, and processes with the environment and emergent function have been proposed but remain untested. Here we refine and test a recent conceptual framework using hyporheic zone sediments exposed to wetting–drying transitions. Our refined framework includes relationships between cumulative properties of a microbial community (e.g., microbial membership, community assembly properties, and biogeochemical rates), environmental features (e.g., organic matter thermodynamics), and emergent ecosystem function. Our primary aim was to evaluate the hypothesized relationships that comprise the conceptual framework and contrast outcomes from the whole and putatively active bacterial and archaeal communities. Throughout the system we …

Making Space For Social And Emotional Learning In Science Education, Erin Ingram, Kristie Reddick, Jessica M. Honaker, Gwen A. Pearson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Social-emotional learning (SEL) is known to improve student outcomes but is rarely combined with STEM. In this paper we present an action research study to examine the impact of a STEM + SEL curriculum intervention to address a real-world school conflict. One hundred sixth–eighth graders and four teachers participated in an in-person facilitation of a SEL Arthropod curriculum, DIFFERENT. After the intervention, students completed open-ended couplet statements about arthropod behavior, tarantulas, and humans designed to measure sentiment change. Answers were manually coded using inductive coding on a scale of negative (1) to positive (5). Statement sentiments significantly shifted from negative …

Assessment Of The Effects Of Airflow Conditions Related To Hop Drying, David Mabie

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

Hops have been utilized by brewers for centuries to contribute bitterness, antimicrobial preservation and desirable aromatic profiles to beer. The hop cone is a small, lightweight, high moisture content flower which produces lupulin glands containing resins and essential oils that contribute desirable characteristics to beer. Due to the high harvest moisture content (75% wet basis), hops must be rapidly dried to properly preserve them for future processing and brewing. While hops have been dried for centuries, most literature from the past century has focused on drying to minimizing loss to the resin or physical cone structure. The objectives of this …

Evaluating Prediction Models Of Creep And Drying Shrinkage Of Self-Consolidating Concrete Containing Supplementary Cementitious Materials/Fillers, Micheal Asaad, George Morcous

Durham School of Architectural Engineering and Construction: Faculty Publications

Supplementary cementitious materials (SCMs) and fillers play an important role in enhancing the mechanical properties and durability of concrete. SCMs and fillers are commonly used in self-consolidating concrete (SCC) mixtures to also enhance their rheological properties. However, these additives could have significant effects on the viscoelastic properties of concrete. Existing models for predicting creep and drying shrinkage of concrete do not consider the effect of SCM/filler on the predicted values. This study evaluates existing creep and drying shrinkage models, including AASHTO LRFD, ACI209, CEB-FIP MC90-99, B3, and GL2000, for SCC mixtures with different SCMs/fillers. Forty SCC mixtures were proportioned for …

A Single Cell Pair Mechanical Interrogation Platform To Study Cell–Cell Adhesion Mechanics, Amir Monemianesfahani

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

Cell-cell adhesion complexes are macromolecular adhesive organelles that integrate cells into tissues. Perturbations of the cell-cell adhesion structure or relatedmechanotransduction pathways lead to pathological conditions such as skin and heart diseases, arthritis, and cancer. Mechanical stretching has been used to stimulate the mechanotransduction process originating from the cell-cell adhesion and cell-extracellular matrix (ECM) complexes. The current techniques, however, have limitations on their ability to measure the cell-cell adhesion force directly and quantitatively. These methods use a monolayer of cells, which makes it impossible to quantify the forces within a single cell-cell adhesion complex. Other methods using single cells or cell …

Power-Over-Tether Unmanned Aerial System Leveraged For Trajectory Influenced Atmospheric Sensing, Daniel Rico

School of Computing: Dissertations, Theses, and Student Research

The use of unmanned aerial systems (UASs) in agriculture has risen in the past decade and is helping to modernize agriculture. UASs collect and elucidate data previously difficult to obtain and are used to help increase agricultural efficiency and production. Typical commercial off-the-shelf (COTS) UASs are limited by small payloads and short flight times. Such limits inhibit their ability to provide abundant data at multiple spatiotemporal scales. In this thesis, we describe the design and construction of the tethered aircraft unmanned system (TAUS), which is a novel power-over-tether UAS configured for long-term, high throughput atmospheric monitoring with an array of …

The Facility Infection Risk Estimator™: A Web Application Tool For Comparing Indoor Risk Mitigation Strategies By Estimating Airborne Transmission Risk, Marcel Harmon, Josephine Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

The COVID-19 pandemic created needs for (a) estimating the existing airborne risk of infection from SARS-CoV-2 in existing facilities and new designs and (b) estimating and comparing the impacts of engineering and behavioural strategies for contextually reducing that risk. This paper presents the development of a web application to meet these needs, the Facility Infection Risk Estimator™, and its underlying Wells–Riley based model. The model specifically estimates (a) the removal efficiencies of various settling, ventilation, filtration and virus inactivation strategies and (b) the associated probability of infection, given the room physical parameters and number of individuals infected present with either …