Engineering Commons^™

Characterization Of A Carbon Fiber Based Broadband Microwave Absorber, Ha Tran, Branimir Pejcinovic, Robert Doneker, Kent Thompson, Adithya Ramachandran

Electrical and Computer Engineering Faculty Publications and Presentations

This paper reports the development and characterization of a novel ultra-wideband microwave absorber material (MAM) based on vertically aligned carbon fibers and ferrite beads. This specific material combination and manufacturing process allows MAM design that is thin, lightweight, and broadband. The material is prepared using a flocking process in which its components are electrostatically deposited on top of an adhesive substrate. Distinct material properties of the substrate and materials layers require characterization done with two separated layers. The microwave absorption characteristics are studied first by rectangular waveguide measurements at X and Ku bands that yield complex electric permittivity and magnetic …

Bht-Qaoa: The Generalization Of Quantum Approximate Optimization Algorithm To Solve Arbitrary Boolean Problems As Hamiltonians, Ali Al-Bayaty, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

A new methodology is introduced to solve classical Boolean problems as Hamiltonians, using the quantum approximate optimization algorithm (QAOA). This methodology is termed the “Boolean-Hamiltonians Transform for QAOA” (BHT-QAOA). Because a great deal of research and studies are mainly focused on solving combinatorial optimization problems using QAOA, the BHTQAOA adds an additional capability to QAOA to find all optimized approximated solutions for Boolean problems, by transforming such problems from Boolean oracles (in different structures) into Phase oracles, and then into the Hamiltonians of QAOA. From such a transformation, we noticed that the total utilized numbers of qubits and quantum gates …

Exploring The Relationship Between Covid-19 Transmission And Population Mobility Over Time, Tanmoy Bhowmik, Naveen Eluru

Civil and Environmental Engineering Faculty Publications and Presentations

This study explores the dynamic relationship between COVID-19 transmission and transportation mobility, with an emphasis on understanding the time-varying bidirectional interplay across the different phases of the pandemic. To gain insight into this relationship, we analyzed county-level data on transmission and mobility patterns from the United States over a 74-week period using a comprehensive list of factors including: temporal factors, socio-demographics, health indicators, health care infrastructure attributes, and spatial factors. For our analysis, we proposed a simultaneous econometric model system that explicitly accounts for the bidirectional relationship between COVID-19 transmission and mobility patterns while also accounting for the influence of …

Flexible Load Conformance: A Work-In-Progress White Paper, Dana Paresa, Robert B. Bass

Electrical and Computer Engineering Faculty Publications and Presentations

Utilities have used residential loads for providing grid services to utility customers for decades, particularly for demand response. However, the number of customers participating in such programs remains low. New Flexible Load Management strategies for providing grid services have the potential to accelerate customer participation. Efforts to improve customer participation and experience will result in increased load balancing capacity of demand response, which will benefit both customers and electric utilities. This white paper investigates whether current smart grid devices (specifically water heaters) can provide needed services while meeting ANSI/CTA-2045 standard requirements.

Improved Parameters Of Anand Model And Advanced Fea Technique For Low-Cycle Fatigue Life: Finite Element Analysis Models For Pb-Free Solder And Pb Solder In Real Life Ball Gird Ally Package, Hamidreza Nahavandi

Dissertations and Theses

The present study uses the finite element method to evaluate the fatigue life of solder joints of plastic ball grid array packages (PBGA) under thermal-cycling conditions. A Series of precise 3D FE models for solder joints of plastic ball grid array packages is created to improve reliability prediction accuracy. Damage parameters are obtained from the FEA results and used to estimate solder balls’ thermal fatigue life. The Coffin-Manson equation is employed. The predicted thermal fatigue lives are discussed in detail.

Due to marketing and legislative pressures, Pb-free solder is fast becoming a reality in electronic manufacturing. The industry has concluded …

Strategies To Mitigate Electrostatic Charging During Coffee Grinding, Joshua Méndez Harper, Robin E. Bumbaugh, Christopher H. Hendon

Electrical and Computer Engineering Faculty Publications and Presentations

Summary: Coffee grinding generates electrostatically charged particles, causing clumping, spark discharge, and beyond. When brewing, the particle aggregates affect liquid-solid surface accessibility, leading to variable extraction quality. Here, we study four charge mitigation strategies. De-electrification is readily achieved by adding small amounts of water to whole beans or by bombarding the grounds with ions produced from a high-voltage ionizer. While these techniques helped reduce visible mess, only water inclusion was found to impact coffee extracts prepared as espresso. Wetting whole beans with less than 0.05 mL/g resulted in a marked shift in particle size distribution, by preventing clump formation and …

2024 Summer Proceedings Teuscher Lab, Teuscher Group, Christof Teuscher, Chelsea Ogbede, Lauren Sanday, Sofia Vargas, Artem Arefev

altREU Projects

How will computation evolve in the coming years? What problems can be tackled using artificial intelligence, in a world increasingly driven by data? And how can that data be used to better inform our decisions as a society? In this unique collection of research projects, each chapter represents a distinct work undertaken by a single individual or a group of students as part of the altREU program led by Christof Teuscher. The projects, rooted in applications of artificial intelligence and innovative computation techniques, examine impactful solutions to numerous pressing challenges affecting communities around the world.

A Systematic Unified Approach For Addressing Temporal Instability In Road Safety Analysis, Kazi Redwan Shabab, Tanmoy Bhowmik, Mohamed H. Zaki, Naveen Eluru

Civil and Environmental Engineering Faculty Publications and Presentations

Multivariate models are widely employed for crash frequency analysis in traffic safety literature. In the context of analyzing data for multiple instances (such as years), it becomes essential to evaluate the stability of parameters over time. The current research proposes a novel approach, labelled the mixed spline indicator pooled model, that offers significant enhancement relative to current approaches employed for capturing temporal instability. The proposed approach entails carefully creating independent variables that allow us to measure parameter slope changes over time and can be easily integrated into existing methodological frameworks. The current research effort compares four multivariate model systems: year …

Machine Learning Framework For Predicting Reliability Of Solder Joints, Robert Lee Jones

Dissertations and Theses

This paper presents the techniques and framework to produce an explainable machine learning model for predicting the reliability of solder joints exposed to thermal cycle testing. While machine learning techniques have become prevalent for many engineering and data analysis tasks, the complexity of the model occludes valuable information which can be used to refine the data, tune model parameters, and aid in scientific discovery. By exposing the relationships within the model, users can have greater confidence in the use and employment of it. The purpose of this study is to show how useful relationships can be obtained from a traditional …

A Configurable Real-Time Event Detection Framework For Power Systems Using Swarm Intelligence Optimization, Umar Farooq, Midrar Adham, Mohammed Alsaid, Robert B. Bass

Electrical and Computer Engineering Faculty Publications and Presentations

Power system balancing authorities are routinely affected by sudden frequency fluctuations. These frequency events can take the form of negligible frequency deviations or more severe emergencies that can precipitate cascading outages, depending on the severity of the disturbance and efficacy of remedial action schema. It is imperative to arrest such disturbances quickly by activating primary frequency control measures. This manuscript proposes a configurable event detection framework using optimization methods to tune a detection algorithm to detect events as specified by experts from a Balancing Authority. The utility of the detection framework is demonstrated using a regression-based frequency event detection algorithm …

Extended Time, Elevated Expectations: The Unappreciated Downsides Of Pausing The Tenure Clock, Maria A. Holland, Katharina Maisel, Carolyn B. Ibberson, Laura K. Wiley, David C. Burnett, Emily M. Mace, Mary Williard Elting

Electrical and Computer Engineering Faculty Publications and Presentations

In 1971, Stanford became the first university to introduce tenure clock extensions in academia for new mothers. The American Association of University Professors (AAUP) began recommending such policies a few years later, and in 2001, modified their recommendation to include primary or coequal caregivers, following either the birth or adoption of a child (1). By 2004, 43% of 255 surveyed institutions had formal clock-stop policies...

Layered Naba2m3q3(Q2) (M = Cu Or Ag; Q = S Or Se) Chalcogenides And Local Ordering In Their Mixed-Anion Compositions, Ayat Tassanov, Huiju Lee, Yi Xia, James M. Hodges

Mechanical and Materials Engineering Faculty Publications and Presentations

Three new NaBa2M3Q3(Q2) (M = Ag or Cu; Q = S or Se) chalcogenides were prepared by using solid-state methods and structurally characterized by using single-crystal X-ray diffraction. NaBa2Ag3Se3(Se2) and NaBa2Cu3Se3(Se2) crystallize in monoclinic space group C2/m and have a two-dimensional structure composed of edge-sharing MSe4/4 tetrahedra separated by Na+ and Ba2+ cations, along with (Se2)2– dimers at the center of the spacings between [M3Se3]3– slabs. NaBa2Ag3S3(S2) adopts a related structure with space group C2/m but has additional, crystallographically distinct Ag atoms in the [Ag3S3]3– layer that are linearly coordinated. NaBa2Ag3Se3(Se2) and NaBa2Ag3S3(S2) have indirect band gaps measured to be …

Comparing The Performance Of Different Missing Data Imputation Approaches In Discrete Outcome Modeling, Md Istiak Jahan, Tanmoy Bhowmik, Lauren Hoover, Naveen Eluru

Civil and Environmental Engineering Faculty Publications and Presentations

Although several approaches exist for data imputation, these approaches are not commonly applied in transportation. The current paper is geared toward assisting transportation researchers and practitioners in developing models using datasets with missing data. The study begins with a data simulation exercise evaluating different solutions implemented for missing data. The dimensions considered in our analysis include: the nature of independent variables, different types of missing variables, different shares of missing values, multiple data sample sizes, and evaluation of single imputation (SI), multiple imputation (MI) and complete case data (CCD) approach. The comparison is conducted by adopting the appropriate inference process …

Story Of Your Lazy Function’S Life: A Bidirectional Demand Semantics For Mechanized Cost Analysis Of Lazy Programs, Liyao Xia, Laura Israel, Maite Kramarz, Stephanie Weirich, Koen Claessen, Nicolas Coltharp, Yao Li

Computer Science Faculty Publications and Presentations

Lazy evaluation is a powerful tool that enables better compositionality and potentially better performance in functional programming, but it is challenging to analyze its computation cost. Existing works either require manually annotating sharing, or rely on separation logic to reason about heaps of mutable cells. In this paper, we propose a bidirectional demand semantics that allows for extrinsic reasoning about the computation cost of lazy programs without relying on special program logics. To show the effectiveness of our approach, we apply the demand semantics to a variety of case studies including insertion sort, selection sort, Okasaki's banker's queue, and the …

Five Pivotal Practices For Leaders To Cultivate Empathy Within Virtual Scrum Teams, Dahm Mongkol Hongchai, Charles M. Weber

Engineering and Technology Management Faculty Publications and Presentations

In the digital and global economy, business leaders need more than just business and technology competencies; they also require empathy. However, there is a notable scarcity of research on empathy in Scrum for product development. This study aims to uncover critical insights into how leaders can foster empathy within virtual Scrum teams. Accordingly, this paper proposes five pivotal themes leaders can employ: Scrum fundamentals, meditation, self- and other-analysis, healthy interactions, and informal connections. These vital strategies offer actionable methods for leaders seeking to enhance empathy within their virtual Scrum teams.

Strengthening Capacity In Industrial Revolution 4.0 (Ir 4.0): A Case Study On Training Product-Service Systems Between The Us And Vietnam, Man Hang Yip, Ana Sofia Castellanos Santarnaria, Julia J. Babcock

Engineering and Technology Management Faculty Publications and Presentations

This case study analyzes how value is created in the development process of a collaborative training product-service system (PSS) designed for provincial government officials in Vietnam. This initiative, part of the USAID Strengthening Provincial Capacity (USAID SPC) project, encapsulates a series of training solutions designed to empower officials with key skills in engineering and technology management, including the knowledge to improve global value chains, upgrade technology infrastructure and sustainable production models. A primary driver for the “four-day course delivery”, the PSS analyzed in this study, was to bolster economic competitiveness at the provincial level in the context of Industrial Revolution …

Predicting Hurricane Evacuation Behavior Synthesizing Data From Travel Surveys And Social Media, Tanmoy Bhowmik, Naveen Eluru, Samiul Hasan, Aron Culotta, Kamol Chandra Roy

Civil and Environmental Engineering Faculty Publications and Presentations

Evacuation behavior models estimated using post-disaster surveys are not adequate to predict real-time dynamic population response as a hurricane unfolds. With the emergence of ubiquitous technology and devices in recent times, social media data with its higher spatio-temporal coverage has become a potential alternative for understanding evacuation behaviour during hurricanes. However, these data are often associated with selection bias and population representativeness issues. To that extent, the current study proposes a novel data fusion algorithm to combine heterogeneous data sources from transportation systems and social media, in a unified framework to understand and predict real-time population response during hurricanes. Specifically, …

Organizational Reliability And Resilience As A Dynamic System: Knowledge Modeling With Fuzzy Cognitive Maps, Antonie J. Jetter, Ahmed A. Alibage, Nan Peter Liang

Engineering and Technology Management Faculty Publications and Presentations

Safety research in complex environments recommends that high-hazard industries improve reliability and increase their capacity for resilience by enacting principles for high-reliability organizing (HRO). This view has been highly influential in many industries, ranging from aviation to hospitals, and is at the core of many safety culture programs. However, even though HRO principles originated in business practice and were observed in diverse organizations, practitioners frequently struggle to enact them in the contexts of their work. This is likely caused by two limitations of current research: principles are insufficiently specified and the interdependencies between them, such as mutually reinforcing vs. tradeoff …

Power Resilience Planning Under The Threat Of Artificial Intelligence, Chip Corbett, Cuong Nguyen, Dahm M. Hongchai, Prajakta Thorat, Pavithra Prasad, Sarah Von Schimmelmann, Charles M. Weber, Timothy R. Anderson

Engineering and Technology Management Faculty Publications and Presentations

The earth is an unstable planet. Change is constant and frequently chaotic. It is very important to plan carefully to manage changes that can be anticipated now, and to cover potential issues that might not yet have been discovered. The dawn of artificial intelligence (AI) presents a host of new concerns and opportunities. The criteria for evaluation are diverse and complex. Cybersecurity is absolutely essential, yet advances in technology have created an internet of things (IoT) where threat vectors might gain access to critical command and control elements through trillions of connected IoT devices. Whereas elegant zero trust cybersecurity models …

Quantifying Relationships In Fuzzy Cognitive Maps Based On Content Analysis Of Unstructured Research Texts, Ahmed Alibage, Antonie J. Jetter, Elpiniki Papageorgiou

Engineering and Technology Management Faculty Publications and Presentations

FCM projects often rely on knowledge-based approaches, such as expert interviews, which can be challenging to conduct because they require extensive expert participation. We propose a novel alternative to create FCM models based on expert knowledge that is already codified in research texts and other publications. In this approach, thematic network analysis identifies FCM concepts and signed causal connections, while computation of t-coefficient is used to determine the weights of the identified edges. We introduce and evaluate the approach in the context of a real-world system modeling project that is based on 47 carefully selected, peer reviewed research publications on …

Improving Attendance To Achieve Organizational Goals: A Case Study Of Human-Centered Design In A Small Us Plant-Based Food Manufacturer, Angel Contreras-Cruz, Eduardo Ahumada-Tello

Engineering and Technology Management Faculty Publications and Presentations

Plant-based food manufacturing companies face high staff turnover rates and attendance problems. It is challenging for those companies to maintain an acceptance level of employee retention and attendance to achieve their objectives. Companies rely on front-line employees to meet production plans, but employees who do not show up at work jeopardize companies' operations. Additional challenges, such as retaining and attracting talent after the COVID-19 pandemic, are present daily for several U.S. organizations. This study analyzes attendance data from the case study company to design an attendance policy. Attendance data suggested that nearly 60 percent of the operational workforce had attendance …

Mental Models Of Translational Scientists, Rasnia Tabpla, Antonie J. Jetter

Engineering and Technology Management Faculty Publications and Presentations

Translational science aims to bridge the gap between scientific discoveries and practical application yet faces challenges in achieving high success rates. This study examines the effective engagement of translational scientists, who play a key role in the translation process. It uses Fuzzy Cognitive Maps (FCMs) to analyze the scientists' mental models and identify common concepts related to success factors, such as ability, resources, opportunity, and entrepreneurial competencies. It then compares the mental models of the scientists and finds that mental models exhibit similarities, yet variations exist such as density and connectedness. Scenario analysis with FCM is then used to identify …

Technology Convergence And Its Influence On Innovation Networks: An Assessment Of Emerging Trends, Shuying Li, Wudan Ma, Xiaoyu Wang, Xian Zhang, Haiyun Xu, Edwin Garces, Tugrul U. Daim

Engineering and Technology Management Faculty Publications and Presentations

AI-age technologies will evolve at an accelerated pace, driven by long-term mutually beneficial symbiosis. Technology convergence will disrupt existing industrial technology fields in general. Assessing and predicting technology convergence will become an important technology management issue in the AI era, providing new clues for distinguishing key technologies in innovation. Existing analytical models prefer to detect retrospective convergence. The role of emerging converging technologies in developing new technologies, generating new applications, and facilitating collaboration and commercialization across different phases is not well understood. In this paper, we build a technology co-occurrence network from the perspective of technology evolution and community detection, …

Hierarchy Of Exchange-Correlation Functionals In Computing Lattice Thermal Conductivities Of Rocksalt And Zinc-Blende Semiconductors, Jiacheng Wei, Zhonghao Xia, Yi Xia, Jiangang He

Mechanical and Materials Engineering Faculty Publications and Presentations

Lattice thermal conductivity (𝜅L) is a crucial characteristic of crystalline solids with significant implications for thermal management, energy conversion, and thermal barrier coating. The advancement of computational tools based on density functional theory (DFT) has enabled the effective utilization of phonon quasiparticle-based approaches to unravel the underlying physics of various crystalline systems. While the higher order of anharmonicity is commonly used for explaining extraordinary heat transfer behaviors in crystals, the impact of exchange-correlation (XC) functionals in DFT on describing anharmonicity has been largely overlooked. The XC functional is essential for determining the accuracy of DFT in describing interactions among electrons/ions …

Mmwave Tx-Rx Self-Interference Suppression Through A High Impedance Surface Stacked Ebg, Adewale K. Oladeinde, Ehsan Aryafar, Branimir Pejcinovic

Electrical and Computer Engineering Faculty Publications and Presentations

This paper proposes a full-duplex (FD) antenna design with passive self-interference (SI) suppression for the 28 GHz mmWave band. The reduction in SI is achieved through the design of a novel configuration of stacked Electromagnetic Band Gap structures (EBGs), which create a high impedance path to travelling electromagnetic waves between the transmit and receive antenna elements. The EBG is composed of stacked patches on layers 1 and 2 of a four-layer stack-up configuration. We present the design, optimization, and prototyping of unit antenna elements, stacked EBGs, and integration of stacked EBGs with antenna elements. We also evaluate the design through …

Smart Grid Cybersecurity In The Age Of Artificial Intelligence, Chip Corbett, Charles M. Weber, Timothy R. Anderson

Engineering and Technology Management Faculty Publications and Presentations

The security of the power grid is essential for the proper function of a democratic society, yet it is constantly under threat. The internet of things (loT) will make a bad situation much worse. Misinformation, disinformation, and malinformation (MDM) have been identified as serious threats to our democratic institutions, and that same acronym applies to mobile device management (MDM), and these devices have become ubiquitous. People are notoriously bad at doing basic cybersecurity. With trillions of devices and remote access everywhere, what could possibly go wrong? Now add in the engaging opportunity of distributed energy resources (DERs) and life gets …

Improving Biomimetic Passive Dynamics Of A Quadruped Robot Hind Leg Hip Joint With A 3d Printed Torsion Spring, Haonan Zheng

Dissertations and Theses

The Agile and Adaptive Robotics Lab is interested in researching the neuromuscular control network of legged animal locomotion. To validate the lab's understanding of biological neural control, synthetic neural networks are developed and applied to biologically inspired legged robots. For a synthetic neural network to operate in the same manner as a biological neural network and produce the same locomotor behavior, the robot that the synthetic neural network is controlling must also mimic its biological counterpart. Previous research produced a quadruped robot hind leg designed with biomimetic passive dynamics by installing spring and damper pairs at each joint, however, an …

Enhancement Of Mechanical Properties Of Pcl/Pla/Dmso2 Composites For Bone Tissue Engineering, Kyung-Eun Min, Jae-Won Jang, Cheolhee Kim, Sung Yi

Mechanical and Materials Engineering Faculty Publications and Presentations

Bone tissue engineering shows potential for regenerating or replacing damaged bone tissues by utilizing biomaterials renowned for their biocompatibility and structural support capabilities. Among these biomaterials, polycaprolactone (PCL) and polylactic acid (PLA) have gained attention due to their biodegradability and versatile applications. However, challenges such as low degradation rates and poor mechanical properties limit their effectiveness. Dimethyl sulfone (DMSO₂) has emerged as a potential additive to address these limitations, offering benefits such as reduced viscosity, increased degradation time, and enhanced surface tension. In this study, we investigate tailored composites comprising PLA, PCL, and DMSO₂ to enhance mechanical …

Ultrasonic Cigarettes: Chemicals And Cytotoxicity Are Similar To Heated-Coil Pod-Style Electronic Cigarettes., Esther E. Omaiye, Wentai Luo, Kevin J. Mcwhirter, Prue Talbot

Civil and Environmental Engineering Faculty Publications and Presentations

Our purpose was to test the hypothesis that ultrasonic cigarettes (u-cigarettes), which operate at relatively low temperatures, produce aerosols that are less harmful than heated-coil pod-style electronic cigarettes (e-cigarettes). The major chemicals in SURGE u-cigarette fluids and aerosols were quantified, their cytotoxicity and cellular effects were assessed, and a Margin of Exposure risk assessment was performed on chemicals in SURGE fluids. Four SURGE u-cigarette flavor variants ("Blueberry Ice," "Watermelon Ice," "Green Mint," and "Polar Mint") were evaluated. Flavor chemicals were quantified in fluids and aerosols using gas chromatography/mass spectrometry. Cytotoxicity and cell dynamics were assessed using the MTT assay, live-cell …

Examining Driver Injury Severity In Motor Vehicle Crashes: A Copula-Based Approach Considering Temporal Heterogeneity In A Developing Country Context, Shahrior Pervaz, Tanmoy Bhowmik, Naveen Eluru

Civil and Environmental Engineering Faculty Publications and Presentations

Using data from a developing country, the current study develops a copula-based joint modeling framework to study crash type and driver injury severity as two dimensions of the severity process. To be specific, a copula-based multinomial logit model (for crash type) and generalized ordered logit model (for driver severity) is estimated in the study. The data for our analysis is drawn from Bangladesh for the years of 2000 to 2015. Given the presence of multiple years of data, we develop a novel spline variable generation approach that facilitates easy testing of variation in parameters across time in crash type and …