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Articles 31291 - 31320 of 196383

Full-Text Articles in Engineering

Worst-Case Electromagnetic Coupling To An Accelerometer Using An Equivalent Circuit And Experimental Co-Characterization Methodology, Mohamed Z.M. Hamdalla, Thomas Ory, Aaron Harmon, Daryl G. Beetner, Victor Khilkevich, John Mcgeehan, John Willits, Anthony N. Caruso, Ahmed M. Hassan Jan 2023

Worst-Case Electromagnetic Coupling To An Accelerometer Using An Equivalent Circuit And Experimental Co-Characterization Methodology, Mohamed Z.M. Hamdalla, Thomas Ory, Aaron Harmon, Daryl G. Beetner, Victor Khilkevich, John Mcgeehan, John Willits, Anthony N. Caruso, Ahmed M. Hassan

Electrical and Computer Engineering Faculty Research & Creative Works

Worst-Case Coupling Estimation to a Complex Printed Circuit Board (PCB) System Typically Requires an Expensive Computational And/or Experimental Approach. Therefore, there is a Strong Need for a Deterministic Approach that Can Accurately Predict the Worst-Case Coupling with the Least Computational and Experimental Cost. This Work Uses a Hybrid Equivalent Circuit Approach Coupled with Experimental Measurements to Simplify Predicting the Worst-Case Coupling to an Accelerometer Board. the Predictions of the Proposed Methodology Are Validated using Experimental Measurements with Excellent Agreement.

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Analysis And Modeling Framework Of Common Mode Noise In A Three-Phase Motor System, Manish K. Mathew, Xin Yan, Yuandong Guo, Tanner Fokkens, Li Shen, Daryl G. Beetner, Donghyun Kim Jan 2023

Analysis And Modeling Framework Of Common Mode Noise In A Three-Phase Motor System, Manish K. Mathew, Xin Yan, Yuandong Guo, Tanner Fokkens, Li Shen, Daryl G. Beetner, Donghyun Kim

Electrical and Computer Engineering Faculty Research & Creative Works

Electromagnetic Interference (EMI) Issue is One of the Major Constraints of Power Electronic Converters, Especially for Variable-Speed Systems. in This Work, the Common Mode Noise in a Three-Phase Motor System is Analyzed and Modeled. the Three-Phase Pulse-Width Modulation (PWM) Inverter Creates High Magnitudes of Dv/dt and Di/dt, Resulting in Common Mode Noise and Disturbance Power. in This Paper, the Common Mode Noise and Disturbance Power Modeling Method Are Proposed for Three-Phase Motor Systems. the Proposed Equivalent Circuit Model Comprises Detailed Models for Insulated Gate Bipolar Transistors (IGBTs), EMI Filters, a Three-Phase Motor and a Printed Circuit Board (PCB). the Proposed …

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Analysis Of Voltage Regulator Module (Vrm) Noise Coupling To High-Speed Signals With Vrm Via Designs, Junho Joo, Manish K. Mathew, Soumya Singh, Seema Pk, Arun Chada, Bhyrav Mutnury, Chulsoon Hwang, Donghyun Kim Jan 2023

Analysis Of Voltage Regulator Module (Vrm) Noise Coupling To High-Speed Signals With Vrm Via Designs, Junho Joo, Manish K. Mathew, Soumya Singh, Seema Pk, Arun Chada, Bhyrav Mutnury, Chulsoon Hwang, Donghyun Kim

Electrical and Computer Engineering Faculty Research & Creative Works

The Physical Noise Coupling Mechanism between Voltage Regulator Module (VRM) Noise Coupling to High-Speed Signal Traces is Analyzed and Different Noise Reduction Methods Are Analyzed for the First Time. the Rapid Switching of Field Effect Transistors (FETs) Creates an Unintentional Coupling Region Around the VRM. as High-Speed Traces Are Often Routed in the Inner Signal Layers of Printed Circuit Boards (PCBs) as Striplines for Signal Integrity, the VRM Switching Noise is Mainly Coupled from Noisy Power Vias to the Victim Traces Routed Around the VRM Region. to Analyze Different Coupling Reduction Methods in Practical High-Speed Channels, a Simplified PCB Design …

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Mode-Decomposition-Based Equivalent Via (Mev) Model And Mev Model Application Range Analysis, Chaofeng Li, Kevin Cai, Muqi Ouyang, Manish Kizhakkeveettil Mathew, Mehdi Mousav, Bidyut Sen, Donghyun Kim Jan 2023

Mode-Decomposition-Based Equivalent Via (Mev) Model And Mev Model Application Range Analysis, Chaofeng Li, Kevin Cai, Muqi Ouyang, Manish Kizhakkeveettil Mathew, Mehdi Mousav, Bidyut Sen, Donghyun Kim

Electrical and Computer Engineering Faculty Research & Creative Works

The Mode-Decomposition-Based Equivalent Via (MEV) Model is Proposed in This Paper, which is a Physics-Based Equivalent Model for the High-Speed Channel Modeling. the Application Ranges of the MEV Model Are Analyzed by Varying Anti-Pad Radius, Via Radius, and Distance between the Parallel Plates for a Single Via with Multiple Layers. based on the S-Parameter Comparison with Full-Wave Simulations, the MEV Model is Useful for the Insertion Loss Calculation Up to 100 GHz. Meanwhile, the Return Loss from the MEV Model Shows a High Level of Correlation with Full-Wave Simulation Results Up to 70GHz, Even When the Anti-Pad Radius is Larger …

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Analysis On The Effect Of Averaging Duration On Radio Frequency Dosimetry In Residential Environments, Reza Asadi, Hadi Aliakbarian, Amir Sahraei, Reza Yazdani, Donghyun Kim Jan 2023

Analysis On The Effect Of Averaging Duration On Radio Frequency Dosimetry In Residential Environments, Reza Asadi, Hadi Aliakbarian, Amir Sahraei, Reza Yazdani, Donghyun Kim

Electrical and Computer Engineering Faculty Research & Creative Works

The Potential Hazards of Electromagnetic Waves Have Raised Concerns in Related Authorities to Propose Standards and Limit Lines on the Electromagnetic Field Levels. Most of the Radio Frequency (RF) Dosimetry Measurement Procedures Referred to in Safety Compliance Standards, suggest 6-Minute Averaging, in Addition to Spatial Averaging, Which Can Be Time-Consuming for Primary Measurements. Measurement Analysis in Residential Environment in This Paper Demonstrates that Lowering the Time Interval of Measurements to About 30 Seconds, Which Suggests the Possibility of Reducing the Measurement Time with Minimal Reduction to Measurement Accuracy. for All Measurement Results Shown in This Paper, having a 30-Second Averaging …

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Roughness Losses Computation Through The Partial Elements Equivalent Circuit Method, Fabrizio Loreto, Daniele Romano, Giulio Antonini, Albert E. Ruehli, Mauro Lai Jan 2023

Roughness Losses Computation Through The Partial Elements Equivalent Circuit Method, Fabrizio Loreto, Daniele Romano, Giulio Antonini, Albert E. Ruehli, Mauro Lai

Electrical and Computer Engineering Faculty Research & Creative Works

Conductor Loss Caused by Conductor Surface Roughness is a Critical Aspect in the Design of High-Speed Electronic Systems Since It Significantly Affects their Performances. Well-Established Roughness Models Have Been Proposed over the Years but They Have Been Applied Only to the Transmission Line Models of Interconnects. Typically, the Roughness Models Are Used to Modify the Per-Unit-Length Impedance of the Transmission Line Which is Extracted by 2D Model Methods. The Aim of This Work is to overcome This Limitation Thus Making It Possible to Model Roughness Conductors in the Framework of 3D Full-Wave Methods. More Precisely, it is Presented How to …

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Near Field Scanning-Based Emi Radiation Root Cause Analysis In An Ssd, Xiangrui Su, Wenchang Huang, Junghee Cho, Joonki Paek, Chulsoon Hwang Jan 2023

Near Field Scanning-Based Emi Radiation Root Cause Analysis In An Ssd, Xiangrui Su, Wenchang Huang, Junghee Cho, Joonki Paek, Chulsoon Hwang

Electrical and Computer Engineering Faculty Research & Creative Works

In Modern Portable Electronic Devices, Solid-State Drives (SSDs) Are Commonly Used and Have Been Identified as One of the Dominant Electromagnetic Interference (EMI) Noise Sources that Can Cause RF Desensitization Issues. in This Paper, the EM Emission Source from an SSD Module is Identified and Analyzed using Near Field Scanning and Dipole Moment Source Reconstruction. the Identified Noise Current Path Including the Power Management Integrated Circuit and the Decoupling Capacitor is Validated with the Assistance of Full-Wave Simulation. the Measured Noise Voltage is Used as an Excitation in the Simulation and the Simulated Near Fields Showed a Good Correlation with …

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A Real-Time Microwave Camera Prototype With Zero-Bias Diode Detectors For Emi Source Imaging, Xin Yan, Liang Liu, Victor Khilkevich Jan 2023

A Real-Time Microwave Camera Prototype With Zero-Bias Diode Detectors For Emi Source Imaging, Xin Yan, Liang Liu, Victor Khilkevich

Electrical and Computer Engineering Faculty Research & Creative Works

Emission Source Microscopy (ESM) Could Be Utilized to Localize the Electromagnetic Interference (EMI) Sources that Contribute to the Far-Field Radiation. in Those Cases, the Electrical Field over a Two-Dimensional Plane is Collected by Mechanical Scanning, Resulting in a Long Measurement Time and the Presence of Mechanical Errors. in This Work, a Microwave Camera based on a Two-Dimensional Array of Elliptical Slot Antennas and Diode Detectors is Presented. Multiplexers Are Utilized to Access the Output of Each Detector and the Scanning of the Whole Array Could Be Done Multiple Times Per Second.

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Lifelong Learning Control Of Nonlinear Systems With Constraints Using Multilayer Neural Networks With Application To Mobile Robot Tracking, Irfan Ganie, S. (Sarangapani) Jagannathan Jan 2023

Lifelong Learning Control Of Nonlinear Systems With Constraints Using Multilayer Neural Networks With Application To Mobile Robot Tracking, Irfan Ganie, S. (Sarangapani) Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Presents a Novel Lifelong Multilayer Neural Network (MNN) Tracking Approach for an Uncertain Nonlinear Continuous-Time Strict Feedback System that is Subject to Time-Varying State Constraints. the Proposed Method Uses a Time-Varying Barrier Function to Accommodate the Constraints Leading to the Development of an Efficient Control Scheme. the Unknown Dynamics Are Approximated using a MNN, with Weights Tuned using a Singular Value Decomposition (SVD)-Based Technique. an Online Lifelong Learning (LL) based Elastic Weight Consolidation (EWC) Scheme is Also Incorporated to Alleviate the Issue of Catastrophic Forgetting. the Stability of the overall Closed-Loop System is Analyzed using Lyapunov Analysis. the …

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Decomposition Measurement For Antenna Gain And Radio Sensitivity Of Wireless Receiving System, Chaoqiang Zang, Lidong Chi, Fuhai Li, James L. Drewniak, Gang Feng, Yihong Qi Jan 2023

Decomposition Measurement For Antenna Gain And Radio Sensitivity Of Wireless Receiving System, Chaoqiang Zang, Lidong Chi, Fuhai Li, James L. Drewniak, Gang Feng, Yihong Qi

Electrical and Computer Engineering Faculty Research & Creative Works

A General Procedure for Decomposition Measurements for Receiver Antenna Gain and Radio Sensitivity based on Received Signal Strength Indicator (RSSI) Reporting is Proposed in This Paper. This Procedure Standardizes the Measurement Steps for Eliminating Nonlinear Error in RSSI Reporting. after Path Loss Calibration and RSSI Uncertainty Calibration, the Real Performance of the Antenna and the Radio Working in the Actual Environment of Wireless Receiving System Can Be Measured. the Antenna Gain is Obtained from the Difference between RSSI Reporting and Transmit Power, and the Radio Sensitivity is Obtained from the Transmit Power. This Method Helps to Improve the Development Efficiency …

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Oxidation Layer Formation On Aluminum Substrates With Surface Defects Using Molecular Dynamics Simulation, Emmanuel Olugbade, Hiep Pham, Yuchu He, Haicheng Zhou, Chulsoon Hwang, Jonghyun Park Jan 2023

Oxidation Layer Formation On Aluminum Substrates With Surface Defects Using Molecular Dynamics Simulation, Emmanuel Olugbade, Hiep Pham, Yuchu He, Haicheng Zhou, Chulsoon Hwang, Jonghyun Park

Electrical and Computer Engineering Faculty Research & Creative Works

Aluminum Oxide Layer Affects the Integrity of Electrical Contact and Can Contribute Adversely to Passive Intermodulation (PIM) Behavior in Radio Frequency (RF) Devices, necessitating a Need for Understanding its Formation Mechanism and Realistic Estimation of its Thickness. using ReaxFF Molecular Dynamics Simulation Technique, This Study Investigated the Impact of Surface Defects on Aluminum Oxide Layer Formation. Results Reveal that Crystallographic Orientation Did Not Affect the Kinetics of Oxidation Process of Aluminum. However, the Reaction Kinetics Increased Significantly with Surface Inhomogeneities Such as Cracks, Scratches, and Grain Boundaries. a Non-Uniform Oxide Layer with Thickness Variation in the Range of 72-77% Was …

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Augmented Genetic Algorithm V2 With Reinforcement Learning For Pdn Decap Optimization, Haran Manoharan, Jack Juang, Hanfeng Wang, Jingnan Pan, Kelvin Qiu, Xu Gao, Chulsoon Hwang Jan 2023

Augmented Genetic Algorithm V2 With Reinforcement Learning For Pdn Decap Optimization, Haran Manoharan, Jack Juang, Hanfeng Wang, Jingnan Pan, Kelvin Qiu, Xu Gao, Chulsoon Hwang

Electrical and Computer Engineering Faculty Research & Creative Works

Genetic Algorithms (GAs) Use Many Hyperparameters, and Tuning These Parameters Can Determine the Optimization Performance. a GA with an Augmented Initial Population Was Proposed for Decap Optimization but It Had Convergence Issues by Getting Stuck in the Local Minimum. This Work Uses a Reinforcement Learning (RL) Approach to Adaptively Tune the Hyperparameters of GA during its Operation. with This Approach, the Agent Tries to Change the Parameters So that the GA Does Not Get Stuck in the Local Minimum. the Proposed Method Combining the RL Agent and Augmented GA Showed Better Performance in Terms of Solution Quality and Time Cost. …

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Intelligent Control Schemes For Maximum Power Extraction From Photovoltaic Arrays Under Faults, Azhar Ul-Haq, Shah Fahad, Saba Gul, Rui Bo Jan 2023

Intelligent Control Schemes For Maximum Power Extraction From Photovoltaic Arrays Under Faults, Azhar Ul-Haq, Shah Fahad, Saba Gul, Rui Bo

Electrical and Computer Engineering Faculty Research & Creative Works

Investigation of power output from PV arrays under different fault conditions is an essential task to enhance performance of a photovoltaic system under all operating conditions. Significant reduction in power output can occur during various PV faults such as module disconnection, bypass diode failure, bridge fault, and short circuit fault under non-uniform shading conditions. These PV faults may cause several peaks in the characteristics curve of PV arrays, which can lead to failure of the MPPT control strategy. In fact, impact of a fault can differ depending on the type of PV array, and it can make the control of …

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Predicting Compressive Strength And Hydration Products Of Calcium Aluminate Cement Using Data-Driven Approach, Sai Akshay Ponduru, Taihao Han, Jie Huang, Aditya Kumar Jan 2023

Predicting Compressive Strength And Hydration Products Of Calcium Aluminate Cement Using Data-Driven Approach, Sai Akshay Ponduru, Taihao Han, Jie Huang, Aditya Kumar

Electrical and Computer Engineering Faculty Research & Creative Works

Calcium aluminate cement (CAC) has been explored as a sustainable alternative to Portland cement, the most widely used type of cement. However, the hydration reaction and mechanical properties of CAC can be influenced by various factors such as water content, Li2CO3 content, and age. Due to the complex interactions between the precursors in CAC, traditional analytical models have struggled to predict CAC binders' compressive strength and porosity accurately. To overcome this limitation, this study utilizes machine learning (ML) to predict the properties of CAC. The study begins by using thermodynamic simulations to determine the phase assemblages of …

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Cooperative Deep $Q$ -Learning Framework For Environments Providing Image Feedback, Krishnan Raghavan, Vignesh Narayanan, Sarangapani Jagannathan Jan 2023

Cooperative Deep $Q$ -Learning Framework For Environments Providing Image Feedback, Krishnan Raghavan, Vignesh Narayanan, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In This Article, We Address Two Key Challenges in Deep Reinforcement Learning (DRL) Setting, Sample Inefficiency and Slow Learning, with a Dual-Neural Network (NN)-Driven Learning Approach. in the Proposed Approach, We Use Two Deep NNs with Independent Initialization to Robustly Approximate the Action-Value Function in the Presence of Image Inputs. in Particular, We Develop a Temporal Difference (TD) Error-Driven Learning (EDL) Approach, Where We Introduce a Set of Linear Transformations of the TD Error to Directly Update the Parameters of Each Layer in the Deep NN. We Demonstrate Theoretically that the Cost Minimized by the EDL Regime is an Approximation …

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Analyzing Ground Motion Records With Cvi Fuzzy Art, Dustin Tanksley, Xinzhe Yuan, Genda Chen, Donald C. Wunsch Jan 2023

Analyzing Ground Motion Records With Cvi Fuzzy Art, Dustin Tanksley, Xinzhe Yuan, Genda Chen, Donald C. Wunsch

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper explores using Cluster Validity Indices Fuzzy Adaptative Resonance Theory (CVI Fuzzy ART) to cluster ground motion records (GMRs). Clustering the features extracted from a supervised network trained for predicting the structure damage results in less overfitting from the trained network. Using Cluster Validity Indices (CVIs) to evaluate the clustering gives feedback to how well the data is being classified, allowing further separation of the data. By using CVI Fuzzy ART in combination with features extracted from a trained Convolutional Neural Network (CNN), we were able to form additional clusters in the data. Within the primary clusters, accuracy was …

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Identifying Potential Consequences Of Use Of A Measure Through Stakeholder Interviews, Melissa G. Kuhn, Joanna K. Garner, Shanan L. Chappell, Linda Bol Jan 2023

Identifying Potential Consequences Of Use Of A Measure Through Stakeholder Interviews, Melissa G. Kuhn, Joanna K. Garner, Shanan L. Chappell, Linda Bol

STEMPS Faculty Publications

The advent of Messick’s Contemporary Validity Theory (1994) led researchers in survey and measure design to develop and standardize qualitative and quantitative methods of collecting evidence for the validity of psychological instruments. However, one aspect of this theory, consequential validity, has few agreed-upon evidence-gathering methods (Furr & Bachrach, 2014). This study added a blueprint-driven interview method of collecting forecasted consequences of use of an instrument into the overall process of developing a measure of outreach impact on undergraduate engineering students (Authors, in press). The method, which included a purposeful sampling of end-users, is illustrated with thematically presented results. Potential implications …

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Optimized Deep Learning Audio Tagging Approach, Fatma S. El-Metwally, Ali I. Eldesouky, Sally M. Elghamrawy Jan 2023

Optimized Deep Learning Audio Tagging Approach, Fatma S. El-Metwally, Ali I. Eldesouky, Sally M. Elghamrawy

Mansoura Engineering Journal

Audio signal processing is a method for applying powerful algorithms and techniques to record, improve, save and transmit audio content signals. Audio Tagging (AT) is a challenge that requires predicting the tags of audio clips. Developments in deep learning and audio signal processing have resulted in a significant improvement in audio tagging. Many techniques have been used. Several studies have introduced different audio tagging techniques, but the performance of the results obtained from these studies is insufficient. This study proposes an Optimized Deep Learning Audio Tagging (ODLAT] approach to classify and analyze audio tagging. Each input signal is used to …

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The Role Of Smart Mashrabiya To Provide Daylighting In Office Buildings, Asma Moawad Gad, Hosny A. Dewer, Mai Wahba Madkour Jan 2023

The Role Of Smart Mashrabiya To Provide Daylighting In Office Buildings, Asma Moawad Gad, Hosny A. Dewer, Mai Wahba Madkour

Mansoura Engineering Journal

Mashrabiya is a distinct feature of our architectural legacy and heritage, daylighting is one of the most significant functions of Mashrabiya. The paper aims at studying the impact of Mashrabiya; in particular, the smart Mashrabiya screen façade on daylighting performance and visual comfort. The application of this methodology occurs in two stages: In the first stage, a typical office room with dimensions of 4 x 6 meters, and a 3-meter height is studied to determine the current state of daylighting levels through the suggested eastern, southern, and western openings in the weather of Cairo, Egypt. The second stage examines the …

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Outdoor Commercial Buildings: A Cfd Study Of The Impact Of Streets Layout On Airflow., Basma Maged, Bakr Gomaa, Alaa Sarhan Jan 2023

Outdoor Commercial Buildings: A Cfd Study Of The Impact Of Streets Layout On Airflow., Basma Maged, Bakr Gomaa, Alaa Sarhan

Mansoura Engineering Journal

The impact of the general layout of commercial streets and their orientation relative to prevailing wind direction on urban comfort due to natural ventilation is unknown. To study the natural airflow pattern in the commercial street mall, this research investigates the impact of different building layouts on airflow characteristics. To do this we conduct a parametric CFD simulation for 12 simulation cases, in which the commercial street layout changes to include secondary streets in four different cases. All cases are also subjected to three different wind directions. The study highlights that different wind orientations can significantly impact pedestrian comfort in …

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Urban Transportation Strategy As Urban Sustainable Indicator Frameworks Study Of Masdar City, Abu Dhabi, Rania Badawy Shokry Jan 2023

Urban Transportation Strategy As Urban Sustainable Indicator Frameworks Study Of Masdar City, Abu Dhabi, Rania Badawy Shokry

Mansoura Engineering Journal

— New models are being created for the planning and administration of sustainable cities as the worldwide trend toward urbanization continues. To create Masdar City, a carbon-neutral, zero-waste city that would showcase cutting-edge sustainable city architecture, the Abu Dhabi government declared in 2006 that it intended to invest $22 billion in its construction. This study aims to focus on one of the indicators of the sustainability of cities, which is sustainable transport, and to clarify how sustainable transport can be translated from Theory to Practice, by standing on the concept of sustainable cities and sustainable transport that works to enhance …

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Data-Driven Dynamic Motion Planning For Practical Fes-Controlled Reaching Motions In Spinal Cord Injury, Derek N.N. Wolf, Antonie J. Van Den Bogert, Eric M. Schearer Jan 2023

Data-Driven Dynamic Motion Planning For Practical Fes-Controlled Reaching Motions In Spinal Cord Injury, Derek N.N. Wolf, Antonie J. Van Den Bogert, Eric M. Schearer

Mechanical Engineering Faculty Publications

Functional electrical stimulation (FES) is a promising technology for restoring reaching motions to individuals with upper-limb paralysis caused by a spinal cord injury (SCI). However, the limited muscle capabilities of an individual with SCI have made achieving FES-driven reaching difficult. We developed a novel trajectory optimization method that used experimentally measured muscle capability data to find feasible reaching trajectories. In a simulation based on a real-life individual with SCI, we compared our method to attempting to follow naive direct-to-target paths. We tested our trajectory planner with three control structures that are commonly used in applied FES: feedback, feedforward-feedback, and model …

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Smoke, Air, Fire, Energy (Safe) In Rural California: Critical Reflections On An Interdisciplinary Research Collaboration, Deepti Chatti, Carisse Geronimo, Cassidy Barrientos, Jana Ganion, Malcolm Moncheur, Peter Alstone Phd, Shawn Bourque, Tanya Garcia, Tesfayohanes Yacob Jan 2023

Smoke, Air, Fire, Energy (Safe) In Rural California: Critical Reflections On An Interdisciplinary Research Collaboration, Deepti Chatti, Carisse Geronimo, Cassidy Barrientos, Jana Ganion, Malcolm Moncheur, Peter Alstone Phd, Shawn Bourque, Tanya Garcia, Tesfayohanes Yacob

Humboldt Journal of Social Relations

This article provides a synthesis of the interconnected problems of tenuous energy access, wildfires, and exposures to high air pollution in Indigenous communities in rural California through the lens of ongoing collaborative research being carried out by researchers at Cal Poly Humboldt, Schatz Energy Research Center, Karuk Department of Natural Resources, and the Blue Lake Rancheria Tribe. The collaboration is funded by the Strategic Growth Council of the state of California, and we hope is the beginning of a longer term relationship between all partners. We are an interdisciplinary team of researchers drawing on energy engineering, air pollution science, and …

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Defining Sagittal Plane Gait Mechanics And Joint Loading In People With Marfan Syndrome, Justin Melan Pol Jan 2023

Defining Sagittal Plane Gait Mechanics And Joint Loading In People With Marfan Syndrome, Justin Melan Pol

Theses and Dissertations--Biomedical Engineering

Marfan syndrome (MFS) is a genetic condition that is associated with altered muscle composition, which leads to muscle dysfunction. People with MFS exhibit high instances of lower extremity (LE) joint pain that inhibits their ability to perform activities of daily living, such as walking. Despite these detrimental impacts of MFS, there have been no attempts to characterize the effects of MFS on LE joint loading and health during walking that are associated with LE pain and dysfunction. As people with MFS exhibit a high incidence rate of osteoarthritis (OA), the need to understand the potential alterations in LE extremity mechanics …

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3-Dimensional Muscle Constructs: Using Hydrogels In Order To Model The Effects Of Exercise In Disease Conditions, Mark Mchargue Jan 2023

3-Dimensional Muscle Constructs: Using Hydrogels In Order To Model The Effects Of Exercise In Disease Conditions, Mark Mchargue

Theses and Dissertations--Biomedical Engineering

Currently, there is no standard in vitro model for studying the effects of mechanical stimulation on muscle in type II diabetes. Existing models primarily utilize electrical stimulation, which does not fully recapitulate the effects of exercise. In this thesis, we create a standardized in vitro model of murine muscle that can recapitulate the benefits seen in exercise when mechanically stimulated. Moreover, we show that a type II diabetes environment has similar effects on the muscle in vitro as well as in vivo.

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Multiscale And Multimodality Optical Imaging Of Brain Hemodynamics And Function, Mehrana Mohtasebi Jan 2023

Multiscale And Multimodality Optical Imaging Of Brain Hemodynamics And Function, Mehrana Mohtasebi

Theses and Dissertations--Biomedical Engineering

Frequent measurement of cerebral hemodynamics is crucial for continuous assessment of brain function and health. Low-frequency oscillations (LFOs; < 0.1 Hz) have shown promise as an indicator of altered neurologic activity in the abnormal brain. Moreover, quantification of temporal correlations in LFOs across distinct brain regions enables mapping of regional neurovascular disorders. Portable diffuse optical techniques such as near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS) enable noninvasive and continuous measurements of cerebral oxygenation and cerebral blood flow (CBF), respectively. However, most NIRS/DCS systems use limited numbers of discrete light sources and detectors and thus lack combinations of high temporal/spatial resolution and large field-of-view (FOV) for brain imaging. Recent development of an innovative noncontact speckle contrast diffuse correlation tomography (scDCT) in our lab provides a low-cost and portable tool for high-density imaging of CBF distributions over large FOVs. The scDCT uses a galvo-mirror to remotely deliver coherent point near-infrared light to multiple source positions and a CMOS camera as a high-density 2-D detector array to quantify spatial fluctuations of diffuse laser speckles, resulting from movement of red blood cells. Boundary CBF data were input to a unique finite-element-method (FEM)-based reconstruction algorithm for 3-D imaging of CBF distributions. However, scDCT was hindered for extracting LFOs due to its low sampling rate. In this study, scDCT was optimized to achieve high sampling rates and fast image reconstructions by use of moving window algorithms with parallel computations (Project 1). Power spectral density (PSD) analysis was performed to investigate altered LFOs during transient cerebral ischemia in neonatal piglets. Transient cerebral ischemia caused reductions in both CBF and PSD, supporting inclusion of scDCT in the growing field of LFO analysis. One remaining limitation was the long computational time required for 3-D reconstruction, which prohibited real-time applications. To overcome this limitation, a depth-sensitive diffuse speckle contrast topography (DSCT) method was developed for analyzing scDCT data to achieve fast and high-density 2-D mapping of CBF distribution without the need of complex and time-consuming 3-D reconstructions (Project 2). New head-simulating phantoms with known optical/geometric properties were designed and fabricated to evaluate the spatial resolution and depth sensitivity of DSCT method. In-vivo experiments verified the capability of DSCT in tracking dynamic changes in CBF at different depths during CO2 inhalation and transient cerebral ischemia in rats. In addition to preclinical studies, a low-cost, wearable, fluorescence eye loupe (FLoupe) device was invented for intraoperative visualization of brain tumor margin in the clinic (Project 3). Consistent results were observed against an expensive, large, standard fluorescence operative microscope for the guidance of tumor resection. Overall, through 3 projects this dissertation demonstrated a variety of noninvasive noncontact optical technologies (scDCT, DSCT, and FLoupe) that enabled multiscale (rodents, piglets, and humans) and …

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A Wearable Fiber-Free Optical Sensor For Continuous Measurements Of Cerebral Blood Flow And Oxygenation, Xuhui Liu Jan 2023

A Wearable Fiber-Free Optical Sensor For Continuous Measurements Of Cerebral Blood Flow And Oxygenation, Xuhui Liu

Theses and Dissertations--Biomedical Engineering

Wearable technologies for continuous monitoring of cerebral hemodynamics in freely behaving subjects not only advance our understanding of cognitive processing and adaptive behavior, but also provide vital information for diagnosis and therapeutic assessment of cerebral diseases associated with hypoxia/ischemia. Wearable near-infrared diffuse optical techniques have been used at the bedside to probe deep cerebral hemodynamics, including near-infrared spectroscopy (NIRS) for cerebral oxygenation measurement and diffuse correlation spectroscopy (DCS) for cerebral blood flow (CBF) measurement, respectively. However, most systems are relatively large and expensive, and use rigid fiber-optic probes that significantly constrain subject’s movement. A novel, wearable, fiber-free diffuse speckle contrast …

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Quantitative Microbial Risk Assessment (Qmra) For Urban Stormwater Reuse After Treatment Through A Bioretention System, Isaac Oluk Jan 2023

Quantitative Microbial Risk Assessment (Qmra) For Urban Stormwater Reuse After Treatment Through A Bioretention System, Isaac Oluk

Theses and Dissertations--Civil Engineering

Bioretention, also referred to as a stormwater biofilter, is an extensively used low-impact development technology for both stormwater management and water quality gains. However, little attention has been paid to the acceptability and uncertainty of human health risks associated with the treatment performance of bioretention filter media, and non-potable water reuse scenarios to guide decision-making and system design. This study uses bioretention mechanistic modeling paired with quantitative microbial risk assessment (QMRA) under uncertainty to evaluate human health risks from two reference pathogens – Campylobacter jejuni and Cryptosporidium. Consumption of irrigated green salad, consumption of raw green salad washed with effluent, …

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Do Transportation Network Companies Affect Road Safety Outcomes: A Spatially Detailed Analysis In San Francisco, Vedant Shriniwas Goyal Jan 2023

Do Transportation Network Companies Affect Road Safety Outcomes: A Spatially Detailed Analysis In San Francisco, Vedant Shriniwas Goyal

Theses and Dissertations--Civil Engineering

US traffic fatal deaths have steadily risen since 2010, with the past few years witnessing an unusual trend increase. To reverse such a dangerous trend, one must understand how and why road crashes occur and which factors are causing them. Emerging transportation technologies have shown the potential to improve mobility and safety. However, such technologies are not inherently beneficial and could worsen road safety if not effectively implemented. One such transportation technology that warrants investigation is the rise of ridesharing services, also called Transportation Network Companies (TNCs). The primary goal of the dissertation is to explore the statistical relationship between …

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Prediction Of Chlorine And Disinfection Byproduct Concentration In Water Distribution Systems Using Kypipe And Tthm Regression Models: Application To Two Systems In Kentucky, Yogesh Gautam Jan 2023

Prediction Of Chlorine And Disinfection Byproduct Concentration In Water Distribution Systems Using Kypipe And Tthm Regression Models: Application To Two Systems In Kentucky, Yogesh Gautam

Theses and Dissertations--Civil Engineering

The main objective of this research is to study if the hydraulic and water quality models can be used for water quality analysis of chlorine decay and TTHM formation at various locations across a water distribution system. This is particularly important because it is not always easy or economical to take multiple field samples and analyze them in the laboratory. In this study, models of two different water distribution systems (one more urban and efficiently managed system located in a relative flat topography, and other more rural and less efficiently managed system located in a mountainous topography) were developed in …

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