Engineering Commons^™

Electron Mobility And Velocity In Ai 0.45 Ga 0.55 N-Channel Ultra-Wide Bandgap Hemts At High Temperatures For Rf Power Applications, Hansheng Ye, Mikhail Gaevski, Grigory Simin, Asif Khan, Patrick Fay

Faculty Publications

Ultra-wide bandgap AlGaN has attracted recent attention as a promising channel material for next-generation high electron mobility transistors (HEMTs) for RF power due to its high critical field, excellent transport properties, and potential for operation in extreme environments. However, the effects of temperature on the transport properties are not fully understood. Here, Al_0.62Ga_0.38N/Al_0.45Ga_0.55N HEMTs have been fabricated and characterized up to 150 °C at DC and RF to evaluate the effect of temperature on electron mobility and carrier velocity. Measured results indicate that both mobility and carrier velocity exhibit modest dependence on …

Development Of Controller Area Network Bus Programming For Quarter-Scale Tractor Pulling Sled, Brittani Wacker

Honors Program: Senior Projects (Public)

Usage of Controller Area Network (CAN) technology has allowed for advancements in many industries, including agriculture. Most importantly, its application is useful for refining data acquisition methods. With support from the Quarter-scale Tractor Design Team at UNL, this project united a CAN bus with the team’s current tractor pulling sled. The objectives were to install new instrumentation needed for the CAN bus and to program the updated system utilizing CAN data. The program needed to give the pulling sled functionality and the ability to read and log important pulling data. These goals were all accomplished by implementing new sensors, coding …

Behavior Of One-Way Reinforced Concrete Slabs With Polystyrene Embedded Arched Blocks, Ali Hussein Ali Al-Ahmed, Falah Hasan Ibrahim, Abbas Abdulmajeed Allawi, Ayman El-Zohairy

Faculty Publications

This study presents experimental and numerical investigations on seven one-way, reinforced concrete (RC) labs with a new technique of slab weight reduction using polystyrene-embedded arched blocks (PEABs). All slabs had the same dimensions, steel reinforcement, and concrete compressive strength. One of these slabs was a solid slab, which was taken as a control slab, while the other six slabs were cast with PEABs. The main variables were the ratio of the length of the PEABs to the length of the slab (lp/L) and the ratio of the height of the PEABs to the total slab depth (hP/H). The minimum decrease …

Annealing Post-Drawn Polycaprolactone (Pcl) Nanofibers Optimizes Crystallinity And Molecular Alignment And Enhances Mechanical Properties And Drug Release Profiles, M. D. Flamini, T. Lima, K. Corkum, N. J. Alvarez, Vincent Beachley

Henry M. Rowan College of Engineering Departmental Research

Post-drawn PCL nanofibers can be molecularly tuned to have a variety of mechanical properties and drug release profiles depending on the temperature and time of annealing, which has implications for regenerative medicine and drug delivery applications. Post-drawing polycaprolactone (PCL) nanofibers has previously been demonstrated to drastically increase their mechanical properties. Here the effects of annealing on post-drawn PCL nanofibers are characterized. It is shown that room temperature storage and in vivo temperatures increase crystallinity significantly on the order of weeks, and that high temperature annealing near melt significantly increases crystallinity and molecular orientation on the order of minutes. The kinetics …

Relativistic Magnetron With Diffraction Output And Split Cathode, Artem Kuskov

Electrical and Computer Engineering ETDs

The relativistic magnetron with diffraction output (MDO) is one of the most efficient
microwave sources for sub-100 ns pulses. For pulse widths greater than 100 ns, the microwave production stops due to anode-cathode (A−K) gap closure. In the presence of a solid cathode, the anode and cathode plasmas expand towards each other, shorting the gap. A research team at The Technion Israel Institute of Technology proposed to replace a solid cathode with a split cathode in a magnetron with radial extraction to mitigate gap closure and maximize microwave production from a long pulse generator. Such a cathode geometry comprises an …

Cesspits As Onsite Sanitation Facilities In The Non-Sewered Palestinian Rural Areas: Users’ Satisfaction, Needs And Perception., Rehab Thaher, Nidal Mahmoud, Issam A. Al-Khatib, Yung-Tse Hung

Civil and Environmental Engineering Faculty Publications

The main aim of this research was to assess the problems of using cesspits in the non-sewered areas in the West Bank of Palestine by the means of a questionnaire, with a sample size of 485 households, targeting the cesspits’ owners. People who use cesspits for house onsite wastewater management are not satisfied with them, and most of them complain about high disturbance during discharge of the cesspits (75.5%). Emptying cesspits represents a financial burden, costing 6% of the households’ monthly income. The frequency of cesspits’ emptying decreases substantially when there are onsite GWTPs. People accept that constructing a house …

Considerations For Radio Frequency Fingerprinting Across Multiple Frequency Channels, Jose A. Gutierrez Del Arroyo, Brett J. Borghetti, Michael A. Temple

Faculty Publications

Radio Frequency Fingerprinting (RFF) is often proposed as an authentication mechanism for wireless device security, but application of existing techniques in multi-channel scenarios is limited because prior models were created and evaluated using bursts from a single frequency channel without considering the effects of multi-channel operation. Our research evaluated the multi-channel performance of four single-channel models with increasing complexity, to include a simple discriminant analysis model and three neural networks. Performance characterization using the multi-class Matthews Correlation Coefficient (MCC) revealed that using frequency channels other than those used to train the models can lead to a deterioration in performance from …

Robust Design Methodologies Under Performance Variations For More Than Moore Technologies: Cnfets & 3dics, Satya Keerthi Vendra

Dissertations and Theses

Various emerging technologies have shown great potential of supplementing silicon transistors as Moore's law slows down. One such disruptive technology, Carbon Nanotube Field Effect Transistors (CNFET), among others, promises increased speed and integration with reduced power consumption. However, due to a limited controllability over the Carbon Nano-tube(CNT) growth process, CNFETs show large variations in their performance and behavior. It is therefore difficult to predict and model their behavior while design suggestions are also challenging. CNT variations are important for a realistic delay modelling. Due to the presence of CNT-specific variations, conventional CMOS evaluation techniques cannot be used for CNFETs.

This …

Influence Of Cold Expansion And Aggressive Environment On Crack Growth In Aa2024-T3, Ken Shishino, Christopher Leirer, Alberto Mello

Publications

This research aims to establish the effect of hole cold expansion on fatigue life of pre-cracked material under aggressive environment. A relationship between crack propagation and secondary crack initiation was established for AA2024-T3 cold worked holes subjected to cyclic loads to determine the impact on fatigue life of joints in presence of saline solution. Galvanic corrosion of a steel fastener/aluminum plate assembly was investigated assuming the presence of cracks in the aluminum plates, whose growth will be monitored in-situ with a digital microscope throughout the fatigue process. The cold expansion treatment improved the fatigue life fourfold under a corrosive environment, …

Response Of Green Lake, Wisconsin, To Changes In Phosphorus Loading, With Special Emphasis On Near-Surface Total Phosphorus Concentrations And Metalimnetic Dissolved Oxygen Minima, Dale M. Robertson, Benjamin J. Siebers, Robert Ladwig, David P. Hamilton, Paul C. Reneau, Cory P. Mcdonald, Stephanie Prellwitz, Richard C. Lathrop

Michigan Tech Publications, Part 1

Green Lake is the deepest natural inland lake in Wisconsin, with a maximum depth of about 72 meters. In the early 1900s, the lake was believed to have very good water quality (low nutrient concentrations and good water clarity) with low dissolved oxygen (DO) concentrations occurring in only the deepest part of the lake. Because of increased phos¬phorus (P) inputs from anthropogenic activities in its water¬shed, total phosphorus (TP) concentrations in the lake have increased; these changes have led to increased algal produc¬tion and low DO concentrations not only in the deepest areas but also in the middle of the …

Inventing The Baby Saver: An Activity Systems Analysis Of Applied Engineering At The High School Level, Jessica Gale

Journal of Pre-College Engineering Education Research (J-PEER)

Extant research and engineering education frameworks call for students to engage in personally meaningful engineering projects; however, there are few case studies documenting the work of young engineers working to design solutions to real-world problems that matter to them. This qualitative case study describes the work of a purposively selected group of high school engineering students (the InvenTeam) (n = 15) as they devote a school year to a particularly ambitious invention project: designing and prototyping a device to mitigate deaths occurring when children are left unattended in hot cars. Utilizing cultural historical activity theory as a theoretical and …

Examining Optimal Truck Platoon Configurations To Maximize Its Operational, Safety, And Environmental Performance, Md Adilur Rahim

LSU Master's Theses

Efficient movement of freight is a critical component of the US economy and especially important to the southcentral region where several large freight distribution hubs are located. However, several challenges affect freight movement efficiency, including high fuel and labor costs, vehicular emissions, and traffic safety problems. Truck platooning is a promising application of connected and automated vehicle (CAV) technology that has great potential in addressing current challenges in freight movement in the USA and elsewhere. Few prior studies have examined the potential environmental and traffic operational impacts of truck platooning on freeways. In particular, little is known regarding its impacts …

Co-Occurrence Of Microplastics, Uranium And Arsenic In Heavy Metal-Contaminated Freshwaters And Their Potential Interaction, Jasmine Anne Quiambao

Civil Engineering ETDs

This study identified microplastics and heavy metals in fields sites of freshwater systems in New Mexico and evaluated the interactions of arsenic (As) and uranium (U) with commercial microplastics for acidic and neutral pH in laboratory-controlled conditions. The potential interaction of microplastics with other contaminants is not well-established. Microplastics could interact with heavy metals in ecosystems with naturally elevated background concentrations of metals or affected by anthropogenic activities. Previous studies have found heavy metal contamination in freshwater systems in New Mexico near abandoned mine sites. The objective of this study is (1) to identify and characterize microplastics from metal contaminated …

To Critically Review The Use Of Screencasts For Teaching Land Surveying, Eugen Niculae, Alain Chenaux

Conference papers

Screencasting tools allow for a screen capture of the actions on a computer screen with accompanying audio. This research initially reviews through the literature how screencasting has been used pedagogically and, through this primary research, the application of an existing screencast called Screencast-O-Matic and feedback from students from both Construction Management and Geospatial Surveying Undergraduate Programmes of TU Dublin, where and how it could be deployed for the surveying classes and fieldwork during the pandemic situation. This research occurred when all Irish third-level institutions lectures and tutorials moved online, and access to survey equipment for fieldwork was severely reduced. The …

Components’ Exchanges Between Recycled Materials And Asphalt Binders In Asphalt Mixes, Eslam Deef-Allah, Magdy Abdelrahman, Mohyeldin Ragab

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The focus of this study was to explore the components' exchanges between recycled asphalt shingles (RAS) or reclaimed asphalt pavement (RAP) and virgin asphalt binders (VABs) in the asphalt mixes and to establish their effect on the rutting resistance of the extracted asphalt binders (EABs). Twelve plant mixes and twelve field mixes were gathered as examples of four Superpave mixes containing RAP or RAS. The plant mixes were reheated and compacted in the lab. The field mixes were collected as cores within 2 weeks after the ending of the construction process. The exchanged components were investigated using Fourier transform infrared …

Interpreting Multi-Stage Teaching And Learning Initiatives For Mechanical Engineering Students - A Knowledge Management Perspective For Students, Kevin Delaney, Ger Nagle, Mingzhu Chen

Conference papers

Encouraging students to “think differently”, to “think like an engineer”, to “just solve the problem” is challenging and depends upon many factors such as the prior learning and experiences of the particular students involved. Sometimes it is difficult to convince students to really engage with activities outside their own comfort zones if they cannot see the potential benefits that might accrue through such engagement.

This paper describes a paradigm, inspired by knowledge management, which the authors have used to explain the importance of engaging with teaching and learning activities to undergraduate students. More importantly it helps these students to understand …

Influence Of Phosphorus Sources On The Compressive Strength And Microstructure Of Ferronickel Slag-Based Magnesium Phosphate Cement, Cuirong Yan, Hongyan Ma, Zhongqiu Luo, Xintao Zhou, Luxing Wang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Electric furnace ferronickel slag (EFS) is a typical magnesium-rich industrial by-product discharged from the manufacture of nickel and iron-nickel alloys. The approach to use it as the raw material for the preparation of magnesium phosphate cement (MPC) has potential and proves effec-tive. In this study, three different phosphorus sources (PS) including phosphoric acid (H₃PO₄, PA), sodium dihydrogen phosphate (NaH₂ PO₄, SDP) and potassium dihydrogen phosphate (KH₂ PO₄, PDP) were used to react with EFS to prepare the EFS-based MPC (EMPC), and the effects of raw material mass ratio (EFS/PA, EFS/SDP, …

Encouraging Voluntary Government Action Via A Solar-Friendly Designation Program To Promote Solar Energy In The United States, Xue Gao, Casey I. Canfield, Tian Tang, Hunter Hill, Morgan Higman, John Cornwell

Engineering Management and Systems Engineering Faculty Research & Creative Works

Sustainable development requires an accelerated transition toward renewable energy. In particular, substantially scaling up solar photovoltaics (PV) adoption is a crucial component of reducing the impacts of climate change and promoting sustainable development. However, it is challenging to convince local governments to take action. This study uses a combination of propensity score matching (PSM) and difference-in-differences (DID) models to assess the effectiveness of a voluntary environmental program (VEP) called SolSmart that targets local governments to engage in solar-friendly practices to promote the local solar PV market in the United States. Via specific designation requirements and technical assistance, SolSmart simplifies the …

Madfam: Microarchitectural Data Framework And Methodology, Tor J. Langehaug, Scott R. Graham, Christine M. Schubert Kabban, Brett J. Borghetti

Faculty Publications

In the aftermath of Spectre and Meltdown researchers have proposed a variety of attack detection solutions by applying machine learning to data collected from hardware performance monitoring units. Although many microarchitectural attack detection systems provide high-accuracy detection results, the behavior of the underlying data collection mechanisms is not well described or understood. This research introduces the MicroArchitectural Data Framework And Methodology (MADFAM) to prescribe a systematic approach to collecting and preserving the information available in sequences of microarchitectural data. The proposed framework focuses on hardware performance counters (HPCs) as the primary data source. HPC configuration is complex, which makes it …

Design Of A Week-Long Introduction To Engineering Summer Camp To Increase Interest And Eagerness Of Stem In Young Children, Beth Cannon

Honors Program: Senior Projects (Public)

For this creative project, a one-week camp curriculum was designed for elementary students (Grades 3-5) to introduce engineering. This work includes a rationale and camp curriculum. The rationale describes the research-based design of the curriculum. It outlines engineering basics and why and how to teach engineering to young students. The curriculum intends to introduce engineering to young children and excite the possibility of a future career. The following engineering disciplines are presented throughout the week of camp: mechanical, environmental, civil, electrical, and chemical. The first day of camp focuses on the basics of engineering. Following that, each day of camp …

Scheduling Aircraft Departures To Avoid Enroute Congestion, Johannes Martinez

Scholarly Horizons: University of Minnesota, Morris Undergraduate Journal

When scheduled flights are forecast to overcrowd sections of enroute airspace, an air traffic control authority may need to delay departures. Mixed integer linear programming can be used to compute a schedule that resolves the congestion while bringing the sum of all delays to a minimum. Standard linear programming constraint formulations for such scheduling problems, however, have poor run times for instances of realistic size. A new constraint formulation based on cycles and paths through a route graph reduces run times in computational experiments. It shows particularly strong performance for schedules that approach the worst-case solution times in standard formulations.

Humanity’S Journey To The Red Planet, Robinson Raphael

Student Works

Being the fourth planet in our solar system, Mars is half the size of Earth and constitutes a gravity near 0.38 g. Like its fellow terrestrial planets, it has a central core, rocky mantle, and solid crust. Coupled with a thin atmosphere, its surface features are reminiscent of both the Earth and Moon. Given adequate accessibility, Mars has been a hub for scientific exploration. With past and present robotic missions, they have gradually provided information about the Martian environment to help aid future human exploration. For humanity’s first manned mission to the Martian crater, Aram Chaos, a crew of six …

Bcse: Blockchain-Based Trusted Service Evaluation Model Over Big Data, Fengyin Li, Xinying Yu, Rui Ge, Yanli Wang, Yang Cui, Huiyu Zhou

Big Data Mining and Analytics

The blockchain, with its key characteristics of decentralization, persistence, anonymity, and auditability, has become a solution to overcome the overdependence and lack of trust for a traditional public key infrastructure on third-party institutions. Because of these characteristics, the blockchain is suitable for solving certain open problems in the service-oriented social network, where the unreliability of submitted reviews of service vendors can cause serious security problems. To solve the unreliability problems of submitted reviews, this paper first proposes a blockchain-based identity authentication scheme and a new trusted service evaluation model by introducing the scheme into a service evaluation model. The new …

Big Data With Cloud Computing: Discussions And Challenges, Amanpreet Kaur Sandhu

Big Data Mining and Analytics

With the recent advancements in computer technologies, the amount of data available is increasing day by day. However, excessive amounts of data create great challenges for users. Meanwhile, cloud computing services provide a powerful environment to store large volumes of data. They eliminate various requirements, such as dedicated space and maintenance of expensive computer hardware and software. Handling big data is a time-consuming task that requires large computational clusters to ensure successful data storage and processing. In this work, the definition, classification, and characteristics of big data are discussed, along with various cloud services, such as Microsoft Azure, Google Cloud, …

Exploiting More Associations Between Slots For Multi-Domain Dialog State Tracking, Hui Bai, Yan Yang, Jie Wang

Big Data Mining and Analytics

Dialog State Tracking (DST) aims to extract the current state from the conversation and plays an important role in dialog systems. Existing methods usually predict the value of each slot independently and do not consider the correlations among slots, which will exacerbate the data sparsity problem because of the increased number of candidate values. In this paper, we propose a multi-domain DST model that integrates slot-relevant information. In particular, certain connections may exist among slots in different domains, and their corresponding values can be obtained through explicit or implicit reasoning. Therefore, we use the graph adjacency matrix to determine the …

Sampling With Prior Knowledge For High-Dimensional Gravitational Wave Data Analysis, He Wang, Zhoujian Cao, Yue Zhou, Zong-Kuan Guo, Zhixiang Ren

Big Data Mining and Analytics

Extracting knowledge from high-dimensional data has been notoriously difficult, primarily due to the so-called "curse of dimensionality" and the complex joint distributions of these dimensions. This is a particularly profound issue for high-dimensional gravitational wave data analysis where one requires to conduct Bayesian inference and estimate joint posterior distributions. In this study, we incorporate prior physical knowledge by sampling from desired interim distributions to develop the training dataset. Accordingly, the more relevant regions of the high-dimensional feature space are covered by additional data points, such that the model can learn the subtle but important details. We adapt the normalizing flow …

Toward Intelligent Financial Advisors For Identifying Potential Clients: A Multitask Perspective, Qixiang Shao, Runlong Yu, Hongke Zhao, Chunli Liu, Mengyi Zhang, Hongmei Song, Qi Liu

Big Data Mining and Analytics

Intelligent Financial Advisors (IFAs) in online financial applications (apps) have brought new life to personal investment by providing appropriate and high-quality portfolios for users. In real-world scenarios, identifying potential clients is a crucial issue for IFAs, i.e., identifying users who are willing to purchase the portfolios. Thus, extracting useful information from various characteristics of users and further predicting their purchase inclination are urgent. However, two critical problems encountered in real practice make this prediction task challenging, i.e., sample selection bias and data sparsity. In this study, we formalize a potential conversion relationship, i.e., user→activated user→client and decompose this relationship into …

A Comparison Of Computational Approaches For Intron Retention Detection, Jiantao Zheng, Cuixiang Lin, Zhenpeng Wu, Hong-Dong Li

Big Data Mining and Analytics

Intron Retention (IR) is an alternative splicing mode through which introns are retained in mature RNAs rather than being spliced in most cases. IR has been gaining increasing attention in recent years because of its recognized association with gene expression regulation and complex diseases. Continuous efforts have been dedicated to the development of IR detection methods. These methods differ in their metrics to quantify retention propensity, performance to detect IR events, functional enrichment of detected IRs, and computational speed. A systematic experimental comparison would be valuable to the selection and use of existing methods. In this work, we conduct an …

Expanding Cherenkov Imaging Applications In Radiotherapy: Clinic-Wide In Vivo Treatment Monitoring And Mr-Linac Quality Assurance, Daniel A. Alexander

Dartmouth College Ph.D Dissertations

Radiation therapy treatments have become increasingly complex, striving to improve patient outcomes by delivering sufficient dose for tumor control while sparing more normal tissue. This trend has necessitated the development of additional workflows, such as multilayered incident mitigation strategies and advanced techniques for adapting treatments to account for time-sensitive patient factors. Novel technologies such as optical 3D surface monitoring and magnetic resonance-guided linear accelerators have been developed to assist clinicians in implementing these workflows. We hypothesize that optical imaging methods developed for radiotherapy dose monitoring and measurement can be used to positively impact modern radiation therapy challenges. Cherenkov imaging allows …

The Optimal Relationship Between Actuator Stiffness And Actuation Timing For A Passive Ankle Exoskeleton: An Opensim Simulation, Cody Anderson, Hafizur Rahman, Sara Myers

UNO Student Research and Creative Activity Fair

Introduction

The passive ankle exoskeleton developed by Collins et al. (2015) reduced the metabolic cost of walking with an actuation-timing of ~16% of stance [1]; however, other actuation timings have not been extensively investigated. Therefore, the purpose of this study was to determine the optimal relationship between actuator-stiffness and actuation-timing for a passive ankle exoskeleton by using musculoskeletal modeling.

Methods

Kinematics and ground reaction forces were recorded while a healthy-young male walked on overground force-plates, and these data were exported to a musculoskeletal modeling software (OpenSim) for simulation. A passive ankle exoskeleton model was designed and integrated with a default …