Engineering Commons^™

Cooling Under Applied Stress Rejuvenates Amorphous Alloys And Enhances Their Ductility, Nikolai Priezjev

Mechanical and Materials Engineering Faculty Publications

The effect of tensile stress applied during cooling of binary glasses on the potential energy states and mechanical properties is investigated using molecular dynamics simulations. We study the three-dimensional binary mixture that was first annealed near the glass transition temperature and then rapidly cooled under tension into the glass phase. It is found that at larger values of applied stress, the liquid glass former freezes under higher strain and its potential energy is enhanced. For a fixed cooling rate, the maximum tensile stress that can be applied during cooling is reduced upon increasing initial temperature above the glass transition point. …

Covid-19 And Mental Health/Substance Use Disorders On Reddit: A Longitudinal Study, Amanuel Alambo, Swati Padhee, Tanvi Banerjee, Krishnaprasad Thirunarayan

Computer Science and Engineering Faculty Publications

COVID-19 pandemic has adversely and disproportionately impacted people suffering from mental health issues and substance use problems. This has been exacerbated by social isolation during the pandemic and the social stigma associated with mental health and substance use disorders, making people reluctant to share their struggles and seek help. Due to the anonymity and privacy they provide, social media emerged as a convenient medium for people to share their experiences about their day to day struggles. Reddit is a well-recognized social media platform that provides focused and structured forums called subreddits, that users subscribe to and discuss their experiences with …

Multi-Echo Quantitative Susceptibility Mapping For Strategically Acquired Gradient Echo (Stage) Imaging, Sara Gharabaghi, Saifeng Liu, Ying Wang, Yongsheng Chen, Sagar Buch, Mojtaba Jokar, Thomas Wischgoll, Nasser H. Kashou, Chunyan Zhang, Bo Wu, Jingliang Cheng, E. Mark Haacke

Computer Science and Engineering Faculty Publications

Purpose: To develop a method to reconstruct quantitative susceptibility mapping (QSM) from multi-echo, multi-flip angle data collected using strategically acquired gradient echo (STAGE) imaging. Methods: The proposed QSM reconstruction algorithm, referred to as “structurally constrained Susceptibility Weighted Imaging and Mapping” scSWIM, performs an ℓ1 and ℓ2 regularization-based reconstruction in a single step. The unique contrast of the T1 weighted enhanced (T1WE) image derived from STAGE imaging was used to extract reliable geometry constraints to protect the basal ganglia from over-smoothing. The multi-echo multi-flip angle data were used for improving the contrast-to-noise ratio in QSM through a weighted averaging scheme. The …

Developing An Equivalent Solid Material Model For Bcc Lattice Cell Structures Involving Vertical And Horizontal Struts, Tahseen A. Alwattar, Ahsan Mian

Mechanical and Materials Engineering Faculty Publications

In this study, a body-centered cubic (BCC) lattice unit cell occupied inside a frame structure to create a so-called “InsideBCC” is considered. The equivalent quasi-isotropic properties required to describe the material behavior of the InsideBCC unit cell are equivalent Young’s modulus ( E e ) , equivalent shear modulus ( G e ) , and equivalent Poisson’s ratio ( ν e ) . The finite element analysis (FEA) based computational approach is used to simulate and calculate the mechanical responses of InsideBCC unit cell, which are the mechanical responses of the equivalent solid. Two separates finite element models are then …

Additive Manufacturing And How 3d Printing Is Fighting Covid-19, Raghavan Srinivasan, Ahsan Mian, Joy Gockel, Laura M. Luehrmann

Mechanical and Materials Engineering Faculty Publications

This is the fourth installment in the Shelter in Place (SiP) Lecture series. This installment covers the creative ways that 3D printing has supported efforts to combat the pandemic. It covers the basics of what 3D printing is, some of the various creative projects that have used 3D printing to combat the pandemic, among other topics and questions by the pandemic.

Defect Characterization Of Additively Manufactured Parts, Sabrina D'Alesandro, Joy Gockel, Andrew Harvey

Symposium of Student Research, Scholarship, and Creative Activities Materials

This document describes various image processing techniques to be used for defect characterization of additively manufactured parts. This will help the reader gain knowledge of materials science engineering and the nuances in analyzing data from image processing software.

Additive manufacturing is shaping the manufacturing world through simplistic household printers’ to more complex metal printers used for a variety of applications. Specifically, laser powder bed fusion (LPBF) is an additive manufacturing process that deposits metal powder over the build plate and melts it with a laser in the shape of the build part. In order to make LPBF more efficient with …

How Do Surgeon Preferences And Technique Variances Affect Outcome?, Anastasia Axiopoulou, Caroline G. L. Cao, Katherine Lin Md, Keith Watson Md

Symposium of Student Research, Scholarship, and Creative Activities Materials

The goal of the research project is to create a blue-print of a robot-assisted hysterectomy procedure to support design and evaluation of technology to enhance system performance. To create this blue-print, we will conduct a task analysis, model the cognitive task flow and decision making, and develop a simulation of the hysterectomy procedure. The surgical simulation will be used as a platform to train surgeons on robotic-assisted hysterectomies, as well as to assess learning and performance. Additionally, it will be used to design and develop techniques and novel technology to support surgeons in their performance of the surgery. Current research …

Identifying Easy Indicators Of Dementia, Swati Padhee, Tanvi Banerjee, Valerie L. Shalin, Krishnaprasad Thirunarayan

Symposium of Student Research, Scholarship, and Creative Activities Materials

Alzheimer’s Disease (AD) is a degenerative chronic neurodegenerative disease that affects millions of people and whose care costs billions of dollars. There is growing evidence that variations in speech and language may be early indicators of dementia. One of the most initial symptoms of dementia is speech impairment, including difficulty in finding words and changes to the grammatical structure. These early indicators can be detected by having the patients perform a picture description task, such as the Cookie Theft task from the Boston Diagnostic Aphasia Examination. However, much of the state-of-the-art NLP for dementia has been limited due to the …

Measuring Nomophobia And Exploration Of Consequences And Comorbidities, Sarah Marie Fryman, William L. Romine

Symposium of Student Research, Scholarship, and Creative Activities Materials

Excessive use of smartphones has coined the term “Nomophobia”, or fear of not being able to use your smartphone. For many, these devices have become an extension of ourselves, which raises hesitation on whether or not society has become addicted to smartphones. Specific diagnostic criteria for smartphone addiction have yet to be settled, and even appropriate to use the word “addiction” when describing excessive usage of smartphones is controversial.

We therefore explore utilize current measures to explore the symptoms of nomophobia and their hierarchy, as well as comorbidities including social anxiety, self-esteem, distracted driving and sleep quality. A total of …

Predicting Alcohol Withdrawal In Intensive Care Units, Reza Sadeghi, Tanvi Banerjee, William L. Romine

Symposium of Student Research, Scholarship, and Creative Activities Materials

Alcohol use disorder is a common health issue in older adults who are facing depression caused by retirement, loss of a spouse, pain, and sleep problems. The prolonged, heavy alcohol ingestion will lead to high alcohol dependency such that cessation or reduction of using alcohol causes alcohol withdrawal syndrome (AWS) in roughly 4 to 72 hours after the last drink. During the initial 8 hours, patients face anxiety, insomnia, nausea, and abdominal pain. This condition is followed by high blood pressure, increased body temperature, unusual heart rate, and confusion. If this syndrome does not receive any treatment, the patients will …

Biomechanical Behavior Of A Variable Angle Locked Tibiotalocalcaneal Construct, Farah Hamandi, Gerard Simon, Richard T. Laughlin, Tarun Goswami

Biomedical, Industrial & Human Factors Engineering Faculty Publications

This paper examines the mechanics of the tibiotalocalcaneal construct made with a PHILOS plating system. A failed device consisting of the LCP plate and cortical, locking, and cannulated screws was used to perform the analysis. Visual, microstructure, and fractographic examinations were carried out to characterize the fracture surface topology. These examinations revealed the presence of surface scratching, inclusions, discoloration, corrosion pits, beach marks, and cleavage and striations on the fracture surface. Further examination of the material crystallography and texture revealed an interaction of S, Ni, and Mo-based inclusions that may have raised pitting susceptibility of the device made with Stainless …

Correlating In-Situ Monitoring Data With Internal Defects In Laser Powder Bed Fusion Additive Manufacturing, Andrew J. Harvey

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The presence of defects within laser powder bed fusion (LPBF) parts can lead to reduced mechanical properties and life of components. Because of this, the ability to detect these defects within the parts is critical before the part is subject to its intended loading. Normally the parts are subjected to a quality analysis once they are completed however, this process is typically expensive and time consuming. A solution for these problems is to sense the creation of defects and pores in the parts in-situ, while the part is being fabricated. One proposed method of in-situ monitoring is visible spectroscopy to …

Small-Signal Analysis Of Non-Isolated Ćuk Dc-Dc Converter, Lokesh Kathi

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In the future, renewable energy sources will be the primary energy sources due to non-renewable energy resources depletion. Having a sustainable energy source as an input voltage source for the electrical system is essential. Its applications can be widely used in hybrid solar-wind energy systems, electric vehicles, etc. This converter is invented and named after by Slobodan Cuk. An analysis describing a detailed steady-state operation of the non-isolated Cuk converter operating in continuous-conduction mode (CCM) is provided. The expected steady-state current and voltage waveforms across different components of the converter are analytically derived. Design equations for the converter are provided. …

Design And Simulation Of Boost Dc - Dc Pulse Width Modulator (Pwm) Feed-Forward Control Converter, Calenia L. Franklin

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Military aircraft systems’ power losses are occurring during the loading operations; loading and unloading causes the aircraft systems to lose power. The primary aircraft power source is provided by a 400Hz Ground Power Units (GPU). This GPU provides power to interior lighting, the aircraft cargo compartment, and other electrical systems (i.e. bus). The issues are during loading and unloading on the aircraft, which causes dropout of aircraft power supplied by the external 400Hz GPU. The majority of the military aircraft require a high voltage and a high current with a 270V power output. This thesis analyzes using Feed-Forward PWM Boost …

Single-Pixel Camera Based Spatial Frequency Domain Imaging For Non-Contact Tissue Characterization, Alec M. Petrack

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Optical imaging has demonstrated potential as a medical imaging modality for measuring tissue functionality. Recently, interest in fluorescence guided surgery has emerged from improvements in optical imaging that have allowed real-time feedback. Of the optical imaging modalities, spatial frequency domain imaging (SFDI) has gained a lot of interest. Unlike spectroscopic techniques, such as functional near infrared spectroscopy (fNIRS) and frequency domain spectroscopy that measure bulk tissue properties, SFDI quantifies tissue functionality locally and wide field making it practical for clinical applications. Unfortunately, traditional SFDI systems use multi-pixel detectors, which may not exhibit ideal spectral characteristics, have limited sensitivity, be expensive, …

Identifying Knowledge Gaps Using A Graph-Based Knowledge Representation, Daniel P. Schmidt

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Knowledge integration and knowledge bases are becoming more and more prevalent in the systems we use every day. When developing these knowledge bases, it is important to ensure the correctness of the information upon entry, as well as allow queries of all sorts; for this, understanding where the gaps in knowledge can arise is critical. This thesis proposes a descriptive taxonomy of knowledge gaps, along with a framework for automated detection and resolution of some of those gaps. Additionally, the effectiveness of this framework is evaluated in terms of successful responses to queries on a knowledge base constructed from a …

Improving Pain Management In Patients With Sickle Cell Disease Using Machine Learning Techniques, Fan Yang

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Sickle cell disease (SCD) is an inherited red blood cell disorder that can cause a multitude of complications throughout a patient's life. Pain is the most common complication and a significant cause of morbidity. Since pain is a highly subjective experience, both medical providers and patients express difficulty in determining ideal treatment and management strategies for pain. Therefore, the development of objective pain assessment and pain forecasting methods is critical to pain management in SCD. On the other hand, the rapidly increasing use of mobile health (mHealth) technology and wearable devices gives the ability to build a remote health intervention …

Global Joint Registry: Analysis Of Revision Hip Arthroplasty Data, Alicia M. Runser

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Total hip arthroplasty (THA) has become well-known as being one of the most successful procedures with much long-term positive clinical results. However, revision surgeries are still required. The four most common failure modes for THAs, “reasons for revision”, are loosening, dislocation or instability, fracture, and infection. The goal of a hip arthroplasty register is to gather information on patients that undergo a total hip arthroplasty and factors pertaining to their surgery which may affect their outcome for future years such as the reason for revision. Analysis of this data can help with the allocation of healthcare funds and the efficacy …

Uncertainty-Aware Brain Lesion Visualization, Christina Gillmann, Dorothee Saur, Thomas Wischgoll, Karl T. Hoffman, Hans Hagen, Ross Maciejewski, Gerik Scheuermann

Computer Science and Engineering Faculty Publications

A brain lesion is an area of tissue that has been damaged through injury or disease. Its analysis is an essential task for medical researchers to understand diseases and find proper treatments. In this context, visualization approaches became an important tool to locate, quantify, and analyze brain lesions. Unfortunately, image uncertainty highly effects the accuracy of the visualization output. These effects are not covered well in existing approaches, leading to miss-interpretation or a lack of trust in the analysis result. In this work, we present an uncertainty-aware visualization pipeline especially designed forbrain lesions. Our method is based on an uncertainty …

Medical Education And Assisted Surgery By Ar, Sadan Suneesh Menon, Thomas Wischgoll, Sharon Farra, Cindra Holland

Computer Science and Engineering Faculty Publications

No abstract provided.

Predicting Early Indicators Of Cognitive Decline From Verbal Utterances, Swati Padhee, Anurag Illendula, Megan Sadler, Valerie L. Shalin, Tanvi Banerjee, Krishnaprasad Thirunarayan, William Romine

Computer Science and Engineering Faculty Publications

Dementia is a group of irreversible, chronic, and progressive neurodegenerative disorders resulting in impaired memory, communication, and thought processes. In recent years, clinical research advances in brain aging have focused on the earliest clinically detectable stage of incipient dementia, commonly known as mild cognitive impairment (MCI). Currently, these disorders are diagnosed using a manual analysis of neuropsychological examinations. We measure the feasibility of using the linguistic characteristics of verbal utterances elicited during neuropsychological exams of elderly subjects to distinguish between elderly control groups, people with MCI, people diagnosed with possible Alzheimer's disease (AD), and probable AD. We investigated the performance …

Observing P300 Amplitudes In Multiple Sensory Channels Using Cognitive Probing, Cody Lee Wintermute

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High cognitive workload occurs when excessive working memory resources have been deployed to resolve sensory and cognitive processing, resulting in decremented task performance. The P300 event-related potential (ERP) component has shown sensitivity to cognitive load, and it was hypothesized that an attenuated P300 amplitude could be indicative of high cognitive load. We tested this hypothesis by having eight participants complete two continual performance tasks at increasing workload levels while simultaneously performing an oddball task, evoking P300 ERPs in either the auditory or tactile sensory channel. In our experiment, electroencephalographic recordings were collected over the parietal region to observe the P300 …

Mitigating Atmospheric Phase Errors In Sal Data, Randy S. Depoy Jr.

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Synthetic aperture ladar (SAL) is an emerging remote sensing technology capable of providing high-resolution, interpretable, and timely imagery. SAL and synthetic aperture radar (SAR) are similar in that they provide high-resolution imagery suitable for a wide-variety of applications beyond the diffraction limit of the real aperture. Several advantages of SAL are; realistic imagery resulting from diffuse scattering of optically-rough objects, fine directionality of laser beam making the technology inherently low probability-of-detect, and shorter synthetic aperture collection times, all of which result from operating at optical as opposed to RF wavelengths. With the dramatic decrease in wavelength, SAL systems become more …

Characteristics Of Nanosilver Ink (Utdag) Microdroplets And Lines On Polyimide During Inkjet Printing At High Stage Velocity, Aamir Hamad, Adam Archacki, Ahsan Mian

Mechanical and Materials Engineering Faculty Publications

The performance of printed electronics strongly depends on printing techniques and printing resolution that enhance their electrical and mechanical properties. In this research paper, a Jetlab 4xl was used to control and dispense microdroplets of highly conductive nanosilver ink (UTDAg) on a polyimide substrate. The waveform effect on the droplet generation is characterized by measuring the size and the speed of the drops. The behavior of ejected drops on the substrate is studied by printing lines at different drop spacing and stage velocity. The jetting parameters that drive the piezoelectric actuator were properly determined and two waveforms (bipolar) were created …

The Effect Of Thermal History On The Atomic Structure Andmechanical Properties Of Amorphous Alloys, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The influence of thermal processing on the potential energy, atomic structure, and mechanical properties of metallic glasses is examined using molecular dynamics simulations. We study the three-dimensional binary mixture, which was first relaxed near the glass transition temperature and zero pressure, and then rapidly cooled deep into the glass phase. It was found that glasses annealed at higher temperatures are relocated to higher energy states and their average glass structure remains more disordered, as reflected in the height of the first two peaks in the pair distribution function. The results of mechanical testing demonstrate that both the shear modulus and …

Kv2.1 Channel Clustering In The Sod1-G93a Mouse Model Of Als, Joshua Christopher Harris

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Kv2.1 channels mediate slow-activating K+ rectifier current within the membrane of spinal motoneurons (MNs), and they are known to co-localize with other synapses and ion channels. Although Kv2.1 channels are suggested to regulate MN excitability, little research has gone into investigating its potential contribution to MN-altered excitability in Amyotrophic Lateral Sclerosis (ALS). Using the male SOD1-G93A mouse model of ALS, we examined Kv2.1 cluster area and density in lumbar MNs at four key stages of disease progression. In our experiments, MNs were separated by type via SK3 immunoreactivity in order to isolate and compare the responses of disease-resistant (slow; SK3+) …

Extracting Information From Subroutines Using Static Analysis Semantics, Luke A. Burnett

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Understanding how a system component can interact with other services can take an immeasurable amount of time. Reverse engineering embedded and large systems can rely on understanding how components interact with one another. This process is time consuming and can sometimes be generalized through certain behavior.We will be explaining two such complicated systems and highlighting similarities between them. We will show that through static analysis you can capture compiler behavior and apply it to the understanding of a function, reducing the total time required to understand a component of whichever system you are learning.

Primary Processing Parameters And Their Influence On Porosity And Fatigue Life Of Additively Manufactured Alloy 718, Luke C. Sheridan

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In many structural applications void-like defects cause significant performance debits which call for component redesign or post-processing to account for or remove the defects. For laser powder bed fusion (LPBF) processes, it has been shown that many of these features and their size and shape characteristics are controllable through LPBF process parameter manipulation. For design efforts, however, it is necessary to understand the direct influences of processing on the formation of porosity and the role that individual pores and porosity distributions have on the properties and performance of AM components. Additionally, design criteria must be established to facilitate implementation of …

Finding Data Races In Software Binaries With Symbolic Execution, Nathan D. Jackson

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Modern software applications frequently make use of multithreading to utilize hardware resources better and promote application responsiveness. In these applications, threads share the program state, and synchronization mechanisms ensure proper ordering of accesses to the program state. When a developer fails to implement synchronization mechanisms, data races may occur. Finding data races in an automated way is an already challenging problem, but often impractical without source code or understanding how to execute the program under analysis. In this thesis, we propose a solution for finding data races on software binaries and present our prototype implementation BINRELAY. Our solution makes use …

Hierarchical Anomaly Detection For Time Series Data, Ryan E. Sperl

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With the rise of Big Data and the Internet of Things, there is an increasing availability of large volumes of real-time streaming data. Unusual occurrences in the underlying system will be reflected in these streams, but any human analysis will quickly become out of date. There is a need for automatic analysis of streaming data capable of identifying these anomalous behaviors as they occur, to give ample time to react. In order to handle many high-velocity data streams, detectors must minimize the processing requirements per value. In this thesis, we have developed a novel anomaly detection method which makes use …