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2021

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Articles 2131 - 2160 of 9983

Full-Text Articles in Engineering

Pilot Perception Of Cockpit Organizational Framework’S Impact On Flight Safety And Subordinate Pilot Behavior, Robert D. Allen Oct 2021

Pilot Perception Of Cockpit Organizational Framework’S Impact On Flight Safety And Subordinate Pilot Behavior, Robert D. Allen

Doctoral Dissertations and Master's Theses

Past accidents have indicated that first officers (FO) are less likely to identify and correct captain errors than captains are to correct FO errors. Crew resource management (CRM) training was introduced in the late 1970s to improve captain teamwork skills to utilize the FO more effectively and to increase FO willingness to interject to preserve safety. Despite the effectiveness of CRM training programs, there continue to be incidences where subordinate pilots make weak or ineffective attempts to preserve safety.

This research investigated commercial and airline transport pilots’ perception of the impact cockpit organizational framework (COF) has on both flight safety …


Relative Pose Uncertainty Quantification Using Lie Group Variational Filtering, Christopher W. Hays Oct 2021

Relative Pose Uncertainty Quantification Using Lie Group Variational Filtering, Christopher W. Hays

Doctoral Dissertations and Master's Theses

The applications of visual sensing techniques have revolutionized the way autonomous systems perceive their environment on Earth. In space, the challenge of accurate perception has proven to be a difficult task. Due to adverse lighting conditions, high-noise images are common and degrade the performance of traditional feature-based estimation and perception algorithms. This work explores the applications of a variational filtering scheme founded in Lie Group theory to an autonomous rendezvous, proximity operations and docking problem. Two methodologies, a Monte Carlo approach and an Unscented Transform, for propagating uncertainty using a Lie Group Variational Filter are introduced and developed.


Dynamic Modeling Of Soft Robotic Dielectric Elastomer Actuator, Abdullah De Jesus El Atrache Ceballos Oct 2021

Dynamic Modeling Of Soft Robotic Dielectric Elastomer Actuator, Abdullah De Jesus El Atrache Ceballos

Doctoral Dissertations and Master's Theses

Dielectric elastomers actuators (DEAs) are among the preferred materials for developing lightweight, high compliance and energy efficient driven mechanisms for soft robots. Simple DEAs consist mostly of a homogeneous elastomeric materials that transduce electrical energy into mechanical deformation by means of electrostatic attraction forces from coated electrodes. Furthermore, stacking multiple single DEAs can escalate the total mechanical displacement performed by the actuator, such is the case of multilayer DEAs. The presented research proposes a model for the dynamical characterization of multilayer DEAs in the mechanical and electrical domain. The analytical model is derived by using free body diagrams and lumped …


Rf Fingerprinting Unmanned Aerial Vehicles, Norah Ondus Oct 2021

Rf Fingerprinting Unmanned Aerial Vehicles, Norah Ondus

Doctoral Dissertations and Master's Theses

As unmanned aerial vehicles (UAVs) continue to become more readily available, their use in civil, military, and commercial applications is growing significantly. From aerial surveillance to search-and-rescue to package delivery the use cases of UAVs are accelerating. This accelerating popularity gives rise to numerous attack possibilities for example impersonation attacks in drone-based delivery, in a UAV swarm, etc. In order to ensure drone security, in this project we propose an authentication system based on RF fingerprinting. Specifically, we extract and use the device-specific hardware impairments embedded in the transmitted RF signal to separate the identity of each UAV. To achieve …


Identification Of Factors Associated With Fume Events Using Text Mining And Data Mining Methods, Mary B. O'Connor Oct 2021

Identification Of Factors Associated With Fume Events Using Text Mining And Data Mining Methods, Mary B. O'Connor

Doctoral Dissertations and Master's Theses

Pilots, flight attendants, and passengers can be exposed to toxic compounds when the bleed air that supplies the cabin and flight deck is contaminated with pyrolyzed hydraulic fluid or oil from turbine jet engines. These fume events occur sporadically and can result in acute or chronic exposure in air crews and can have catastrophic consequences if flight crew members become impaired or incapacitated. The purpose of this research was to explore unstructured textual data and identify important factors associated with these events. Models using machine learning algorithms were developed and tested using variables gleaned from the text mining process and …


Socio-Technical Changes For Sustainable Rice Production: Rice Husk Amendment, Conservation Irrigation, And System Changes, Benjamin R. K. Runkle, Angelia L. Seyfferth, Matthew C. Reid, Matthew A. Limmer, Beatriz Moreno-Garcia, Colby W. Reavis, Jasquelin Pena, Michele L. Reba, M. Arlene A. Adviento-Borbe, Shannon R. M. Pinson, Chris Isbell Oct 2021

Socio-Technical Changes For Sustainable Rice Production: Rice Husk Amendment, Conservation Irrigation, And System Changes, Benjamin R. K. Runkle, Angelia L. Seyfferth, Matthew C. Reid, Matthew A. Limmer, Beatriz Moreno-Garcia, Colby W. Reavis, Jasquelin Pena, Michele L. Reba, M. Arlene A. Adviento-Borbe, Shannon R. M. Pinson, Chris Isbell

Biological and Agricultural Engineering Faculty Publications and Presentations

Rice is a staple food and primary source of calories for much of the world. However, rice can be a dietary source of toxic metal(loid)s to humans, and its cultivation creates atmospheric greenhouse gas emissions and requires high water use. Because rice production consumes a significant amount of natural resources and is a large part of the global agricultural economy, increasing its sustainability could have substantial societal benefits. There are opportunities for more sustainable field production through a combination of silicon (Si) management and conservation irrigation practices. As a Si-rich soil amendment, rice husks can limit arsenic and cadmium uptake, …


Development Of A Cyberinfrastructure For Assessment Of The Lower Rio Grande Valley North And Central Watersheds Characteristics, Linda Navarro, Ahmed Mahmoud, Andrew Ernest, Abdoul Oubeidillah, Jessica Johnstone, Ivan Rene Santos Chavez, Christopher Fuller Oct 2021

Development Of A Cyberinfrastructure For Assessment Of The Lower Rio Grande Valley North And Central Watersheds Characteristics, Linda Navarro, Ahmed Mahmoud, Andrew Ernest, Abdoul Oubeidillah, Jessica Johnstone, Ivan Rene Santos Chavez, Christopher Fuller

Biological and Agricultural Engineering Faculty Publications and Presentations

Lower Laguna Madre (LLM) is designated as an impaired waterway for high concentrations of bacteria and low dissolved oxygen. The main freshwater sources to the LLM flow from the North and Central waterways which are composed of three main waterways: Hidalgo/Willacy Main Drain (HWMD), Raymondville Drain (RVD), and International Boundary & Water Commission North Floodway (IBWCNF) that are not fully characterized. The objective of this study is to perform a watershed characterization to determine the potential pollution sources of each watershed. The watershed characterization was achieved by developing a cyberinfrastructure, and it collects a wide inventory of data to identify …


Expanding Temperature Sensing For The Orion Bms 2, Samuel J. Parker Oct 2021

Expanding Temperature Sensing For The Orion Bms 2, Samuel J. Parker

University Honors Theses

Formula SAE (FSAE) is an annual collegiate design competition that takes place across the globe. Portland State University’s team, Viking Motorsports, was committed to designing an Electric Vehicle (EV) for the 2021 FSAE competition. The team designed a completely custom lithium-ion cell battery that is managed by an Orion BMS 2 battery management system. The FSAE rulebook requires a robust temperature monitoring system for any EV power supply. The Orion BMS 2 can only directly collect data from eight temperature sensors, which is not enough to meet FSAE regulation. However, the BMS can be configured to monitor many more sensors …


A 12-Bit 1gs/S Sar-Assisted Pipeline Adc With Harmonic Injecting Residue Amplifier, Liang Fang Oct 2021

A 12-Bit 1gs/S Sar-Assisted Pipeline Adc With Harmonic Injecting Residue Amplifier, Liang Fang

Electrical Engineering Theses and Dissertations

Advanced wireless applications require a medium resolution Radio Frequency (RF) sampling Analog to Digital Converter (ADC). By performing sampling of ADC at RF frequency, the mixer and Intermediate Frequency (IF) amplifier can be implemented in the digital domain, which helps the receiver eliminate troublesome mixing spurs and potentially improves the software-defined ratio of the entire system. By combing the merits of the energy-efficient Successive Approximation Register (SAR) ADC and the high-speed pipeline ADC, the SAR-assisted pipeline ADC achieves superior performance in high-speed medium-resolution ADC. However, with the advance of the process, due to the pure analog implementation, the residue amplifier …


Characterization Of Uav-Based Wireless Channels With Diverse Antenna Configurations, Mahmoud Badi Oct 2021

Characterization Of Uav-Based Wireless Channels With Diverse Antenna Configurations, Mahmoud Badi

Electrical Engineering Theses and Dissertations

In the next wave of swarm-based applications, unmanned aerial vehicles (UAVs) need to communicate with peer drones in any direction of a three-dimensional (3D) space. On a given drone and across drones, various antenna positions and orientations are possible. We know that, in free space, high levels of signal loss are expected if the transmitting and receiving antennas are cross polarized. However, increasing the reflective and scattering objects in the channel between a transmitter and receiver can cause the received polarization to become completely independent from the transmitted polarization, making the cross-polarization of antennas insignificant. Usually, these effects are studied …


A Methodology For Reliability-Based Selection Of System Of Systems, Justin Brown Oct 2021

A Methodology For Reliability-Based Selection Of System Of Systems, Justin Brown

Operations Research and Engineering Management Theses and Dissertations

Currently, Department of Defense (DoD) systems underperform and have inadequate reliability compared to acquisition expectations. Additionally, System of Systems (SoS) complexity and non-quantifiable approaches to selecting systems to perform a mission cause challenges for the decision-maker. Beyond DoD, mission-critical scenarios exist where responses are not data-driven, such as hurricane response, wildfire response, and littoral search and research missions. Optimization of these missions within a short amount of time can not only increase the probability of success and reduce the cost of performing the mission but allow systems to be used for additional missions.

This dissertation presents solution methodologies to address …


An Automated Ar-Based Annotation Tool For Indoor Navigation For Visually Impaired People, Pei Du, Nirupama Bulusu Oct 2021

An Automated Ar-Based Annotation Tool For Indoor Navigation For Visually Impaired People, Pei Du, Nirupama Bulusu

Computer Science Faculty Publications and Presentations

Low vision people face many daily encumbrances. Traditional visual enhancements do not suffice to navigate indoor environments, or recognize objects efficiently. In this paper, we explore how Augmented Reality (AR) can be leveraged to design mobile applications to improve visual experience and unburden low vision persons. Specifically, we propose a novel automated AR-based annotation tool for detecting and labeling salient objects for assisted indoor navigation applications like NearbyExplorer. NearbyExplorer, which issues audio descriptions of nearby objects to the users, relies on a database populated by large teams of volunteers and map-a-thons to manually annotate salient objects in the environment like …


Real Time Simulation And Hardware In The Loop Methods For Power Electronics Power Distribution Systems, Michele Difronzo Oct 2021

Real Time Simulation And Hardware In The Loop Methods For Power Electronics Power Distribution Systems, Michele Difronzo

Theses and Dissertations

System level testing of Power Electronics Power Distribution Systems (PEPDS) can be challenging when fine temporal resolution is required (time step below 100-200ns). In the recent years, our research group has proposed various methods to simulate in real-time PEPDS using FPGAs and time step as small as 50ns. While the proposed methods allow achieving the desired temporal resolution, they are extremely demanding in terms of resources usage and the size of the PEPDS that can be simulated on a single FPGA is strongly limited.

In this dissertation -work that takes as an example application the US Navy electric Ship Zonal …


A Unified Framework Of Deep Learning-Based Facial Expression Recognition System For Diversified Applications, Sanoar Hossain, Saiyed Umer, Vijayan K. Asari, Ranjeet Kumar Rout Oct 2021

A Unified Framework Of Deep Learning-Based Facial Expression Recognition System For Diversified Applications, Sanoar Hossain, Saiyed Umer, Vijayan K. Asari, Ranjeet Kumar Rout

Electrical and Computer Engineering Faculty Publications

This work proposes a facial expression recognition system for a diversified field of appli- cations. The purpose of the proposed system is to predict the type of expressions in a human face region. The implementation of the proposed method is fragmented into three components. In the first component, from the given input image, a tree-structured part model has been applied that predicts some landmark points on the input image to detect facial regions. The detected face region was normalized to its fixed size and then down-sampled to its varying sizes such that the advantages, due to the effect of multi-resolution …


Me-Em 2020-21 Annual Report, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Oct 2021

Me-Em 2020-21 Annual Report, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering Annual Reports

Table of Contents

  • Responsive Research
  • Alumni Impact
  • Innovative Enterprises
  • Enrollment & Degrees
  • Graduates
  • Department
  • Donors
  • Contracts & Grants
  • Patents & Publications


Mid-Movement Error Corrections After Visual And Haptic Perturbations Reflect Latency And Performance Differences, Pablo Gonzalez Polanco Oct 2021

Mid-Movement Error Corrections After Visual And Haptic Perturbations Reflect Latency And Performance Differences, Pablo Gonzalez Polanco

Master's Theses (2009 -)

We examined a key attribute of sensory motor skill: the capability to adjust ongoing actions to correct performance errors that arise during the execution of a task. Fifteen subjects grasped the handle of a horizontal 2D planar robot that enacted a small viscous resistance to the arm movement. The subjects initiated interception movements using a prompted Go cue to quickly catch a pseudo-randomly moving target. On some trials, the robot viscosity field or the target’s motion (speed) was altered without any warning at the time of the Go cue. The viscosity could be increased which made it more difficult to …


Stochastic Modeling For Mobile Manipulators, Xie Jiayu Oct 2021

Stochastic Modeling For Mobile Manipulators, Xie Jiayu

Master's Theses (2009 -)

Mobile manipulators are valuable and highly desired in many fields, especially in industrial environments. However, determining the end effector position has been challenging for scenarios where the base moves at the same time that the arm follows commands to perform specific tasks. Earlier works have attempted to dynamically evaluate the problem of positioning error for mobile manipulators, but there is still room for further improvement. In this thesis, we devise a dynamical model that leverages stochastic search strategies for mobile manipulators. More specifically, we develop a dynamic model that estimates the position of the robot using an Unscented Kalman filter. …


Assessment Of Mitochondrial Dysfunction In Lungs From Rats Exposed To Hyperoxia And The Efficacy Of Duroquinone, Swetha Ganesh Oct 2021

Assessment Of Mitochondrial Dysfunction In Lungs From Rats Exposed To Hyperoxia And The Efficacy Of Duroquinone, Swetha Ganesh

Master's Theses (2009 -)

Dissipation of mitochondrial membrane potential (ΔΨm) is a hallmark of mitochondrial dysfunction. The objective of this thesis was to use a previously developed experimental-computational approach to estimate tissue ΔΨm in intact lungs of rats exposed to hyperoxia, and to evaluate the ability of duroquinone (DQ) to reverse any hyperoxia-induced depolarization of lung Ψm. Rats were exposed to hyperoxia (>95% O2) or normoxia (room air) for 48 hrs, after which lungs were excised and connected to a ventilation-perfusion system. The experimental protocol consisted of measuring the concentration of the fluorescent dye rhodamine 6G (R6G) during three single-pass phases: loading, washing, …


Detecting Invasive Insects Using Uncewed Aerial Vehicles And Variational Autoencoders, Scott Daniel Stewart Oct 2021

Detecting Invasive Insects Using Uncewed Aerial Vehicles And Variational Autoencoders, Scott Daniel Stewart

Master's Theses (2009 -)

In this thesis, we use machine learning techniques to address limitations in our ability to monitor pest insect migrations. Invasive insect populations, such as the brown marmorated stink bug (BMSB), cause significant economic and environmental damages. In order to mitigate these damages, tracking BMSB migration is vital, but it also poses a challenge. The current state-of-the-art solution to track insect migrations is called mark-release-recapture. In mark-release-recapture, a researcher marks insects with a fluorescent powder, releases them back into the wild, and searches for the insects using ultra-violet flashlights at suspected migration destination locations. However, this involves a significant amount of …


Study Of Extensions To The Linear Sampling Method For Electromagnetic Inverse Scattering, Yeasmin Sultana Oct 2021

Study Of Extensions To The Linear Sampling Method For Electromagnetic Inverse Scattering, Yeasmin Sultana

Master's Theses (2009 -)

The linear sampling method (LSM) is a simple and effective qualitative method to reconstruct the support of unknown object by solving inverse scattering problem. The solution is done based on the field radiated by the elementary source located in a set of test points. In this thesis, the LSM formulation, limitations of standard LSM and extensions of LSM are discussed. Standard LSM can reconstruct simply connected objects, but it fails in case of concave or not simply connected objects. However, it can reconstruct the convex hull for such objects. Some extensions to LSM have been proposed to avoid these limitations. …


Aeroacoustic Design Of An Abrasive Blasting Nozzle Using Cfd, Adam Dehli Oct 2021

Aeroacoustic Design Of An Abrasive Blasting Nozzle Using Cfd, Adam Dehli

Master's Theses (2009 -)

Current industrial abrasive blasting nozzles are often loud enough to negatively impact worker health and require employers to implement hearing conservation programs under OSHA noise exposure regulations. Significant opportunity exists for the use of modern computational fluid dynamics software (CFD) in the design of an abrasive blasting nozzle with a focus on reducing the acoustic intensity. Past work using CFD for abrasive blasting nozzle design has focused on improving productivity, ignoring aeroacoustic considerations. ANSYS Fluent software was used to investigate the effect of geometry changes to a commercially available No. 6 venturi nozzle, specifically the addition of a constant cross-section …


Deep Learning Approach For Dynamic Sampling For High-Throughput Nano-Desi Msi, David Helminiak Oct 2021

Deep Learning Approach For Dynamic Sampling For High-Throughput Nano-Desi Msi, David Helminiak

Master's Theses (2009 -)

Mass Spectrometry Imaging (MSI) extracts molecular mass data to form visualizations of molecular spatial distributions. The involved scanning procedure is conducted by moving a probe across and around a rectilinear grid, as in the case of nanoscale Desorption Electro-Spray Ionization (nano-DESI) MSI, where singular measurements can take up to ~5 seconds to acquire high-resolution (better than 10 μm) results. This temporal expense creates a high inefficiency in sample processing and throughput. For example, in a high-resolution nano-DESI study, a single mouse uterine tissue section (2.5 mm by 1.7 mm) had an acquisition time of ~4 hours to acquire 104,400 pixels. …


Experimental Data On Water Soluble Polymers Thermal And Hydrolytic Stability, Reactivity Ratios Of Monomers And Frr Calculation For Thermally Stable Preformed Particle Gels Therefrom, Buddhabhushan Salunkhe, Thomas P. Schuman, Ali Al Brahim, Baojun Bai Oct 2021

Experimental Data On Water Soluble Polymers Thermal And Hydrolytic Stability, Reactivity Ratios Of Monomers And Frr Calculation For Thermally Stable Preformed Particle Gels Therefrom, Buddhabhushan Salunkhe, Thomas P. Schuman, Ali Al Brahim, Baojun Bai

Chemistry Faculty Research & Creative Works

Experimental data on water soluble polymer thermal and hydrolytic stability in acidic, neutral and basic pH conditions in aqueous solution is presented. Thermal and hydrolytic stability of polymer aqueous solutions were monitored in variable pH medium by aging at 130 °C temperature for different aging time. Polymer viscosity measurements were performed periodically for 3 months. Furthermore, this data can serve as a basis of monomer selection for thermally stable hydrogels for applications like oil recovery, hydrogel coatings for steam sterilized medical devices and other applications. Reactivity ratios were determined for monomers associated to the most stable polymers using 1H …


Occurrence And Probabilistic Health Risk Assessment (Pra) Of Dissolved Metals In Surface Water Sources In Southern Peru, Alexander Ccanccapa-Cartagena, Betty Paredes, Corina Vera, Francisco D. Chavez-Gonzales, Elizabeth Joy Olson, Lisa Welp, Nadezhda N. Zyaykina, Timothy R. Filley, David M. Warsinger, Chad T. Jafvert Oct 2021

Occurrence And Probabilistic Health Risk Assessment (Pra) Of Dissolved Metals In Surface Water Sources In Southern Peru, Alexander Ccanccapa-Cartagena, Betty Paredes, Corina Vera, Francisco D. Chavez-Gonzales, Elizabeth Joy Olson, Lisa Welp, Nadezhda N. Zyaykina, Timothy R. Filley, David M. Warsinger, Chad T. Jafvert

School of Mechanical Engineering Faculty Publications

Often, metal and metalloid ions are present in water at concentrations that seriously affect human health; understanding their occurrence is critical, especially in regions such as Peru, where natural volcanic activity and anthropogenic activity have made them more prevalent in local waterbodies. In this study, river, lake, aquifer, and irrigation water samples, collected from the Chili-Quilca, Camana-Majes, Colca-Chivay-Siguas, Oco˜na, Urubamba-Vilcanota, and Titicaca river basins in Southern Peru, were analyzed for transition metals, other metals, metalloids, and other inorganic water constituents. Special emphasis was placed on metals and metalloids regulated by Peruvian Water Quality Standards and those categorized as of “primary …


Nanofluids Improve Energy Efficiency Of Membrane Distillation, Harsharaj B. Parmar, Hamid Fattahi Juybari, Yashwant S. Yogi, Sina Nejati, Ryan M. Jacob, Prashant S. Menon, David M. Warsinger Oct 2021

Nanofluids Improve Energy Efficiency Of Membrane Distillation, Harsharaj B. Parmar, Hamid Fattahi Juybari, Yashwant S. Yogi, Sina Nejati, Ryan M. Jacob, Prashant S. Menon, David M. Warsinger

School of Mechanical Engineering Faculty Publications

Thermal desalination of high salinity water resources is crucial for increasing freshwater supply, but efficiency enhancements are badly needed. Nanomaterial enhancements offer enormous potential for improving promising technologies like membrane distillation (MD). However, while many approaches have been tried, such as nanoparticle solar absorbers or nanomaterial membranes, there have not been studies to directly enhance the fluid properties in MD; via nanofluids. In this work, we examine nanofluids for gap-based MD systems, including the role of nanoscale physics and system-level energy efficiency enhancements. Our model includes the dominant micro-mixing from Brownian motion in fine particle nanofluids (copper oxide) and the …


Recent Updates On Ions And Nutrients Uptake By Halotolerant Freshwater And Marine Microalgae In Conditions Of High Salinity, Abdul Mannan Zafar, Muhammad Asad Javed, Ashraf Aly Hassan, Khalid Mehmood, Endalkachew Sahle-Demessie Oct 2021

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

Department of Civil and Environmental Engineering: Faculty Publications

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


2021 (Fall) Ensi Informer Magazine, Morehead State University. Engineering Sciences Department Oct 2021

2021 (Fall) Ensi Informer Magazine, Morehead State University. Engineering Sciences Department

ENSI Informer Magazine Archive

The ENSI Informer Magazine published in the fall of 2019.


Cyclic Triaxial Testing To Evaluate Factors Affecting The Unsaturated Cyclic Behavior Of A Silty Sand, Zachary R. Howard Oct 2021

Cyclic Triaxial Testing To Evaluate Factors Affecting The Unsaturated Cyclic Behavior Of A Silty Sand, Zachary R. Howard

Theses and Dissertations

This study assesses the cyclic resistance of a non-plastic silty sand, representative of a common mine tailings material. Two series of unsaturated cyclic triaxial tests were conducted, which varied wetting and drying path specimen preparation techniques, initial matric suction, initial net normal stress, and cyclic stress ratio. Specimens prepared using the wetting path experienced significantly higher cyclic resistance than those prepared using the drying path. Specimens that were exposed to higher initial matric suction values experienced higher cyclic resistance than those consolidated with lower initial matric suction values. Initial net normal stress was found to contribute more to specimen cyclic …


Role Of Estrogen In Regulating Diet-Induced Obesity In Females, Ahmed Aladhami Oct 2021

Role Of Estrogen In Regulating Diet-Induced Obesity In Females, Ahmed Aladhami

Theses and Dissertations

Menopause puts a female at risk for several chronic diseases, including an increased risk of obesity. Estrogens are major sex hormones of females that dramatically decrease during menopause. Several murine studies have established the crucial role of estrogen and estrogen receptor alpha (ERα) on energy homeostasis, glucose metabolism, and insulin action. However, previous works have produced contradicting findings, hence, further work is needed to optimize better outcomes. Therefore, my dissertation focuses on optimizing and characterizing different estrogen-deficient models, as well as using novel double transgenic inducible and tissue-specific models that overexpress aromatase (estrogen producing enzyme) and estrogen receptor isomers alpha …


Study Of The Effect Of B-Cell-Intrinsic Mhcii Antigen Presentation On Germinal Center B Cell Evolution Using The Brainbow Mouse Model, Nia Hall Oct 2021

Study Of The Effect Of B-Cell-Intrinsic Mhcii Antigen Presentation On Germinal Center B Cell Evolution Using The Brainbow Mouse Model, Nia Hall

Theses and Dissertations

Major histocompatibility complex class II (MHCII) are molecules that are essential for B cell activation, as well as clonal competition among activated B cell clones during germinal center (GC) reactions. However, it is unknown to what extent MHCII drives the selection of some clones over others. This is of particular importance since MHCII is highly polymorphic with the ability to indirectly alter gutmicrobiome composition by altering the immunoglobulin A (IgA) repertoire. To study this, we utilized a novel triple-transgenic mouse model to assess how B-cellintrinsic MHCII influences GC responses and GC clonal diversity, with an eyeforward to understanding the relevance …