Engineering Commons^™

Als-Induced Excitability Changes In Individual Motorneurons And The Spinal Motorneuron Network In Sod1-G93a Mice At Symptom Onset, Christiana S.I. Draper

Browse all Theses and Dissertations

Amyotrophic lateral sclerosis (ALS) is the most common motorneuron (MN) disease in adulthood. ALS is hallmarked by the progressive loss of MNs in the brain, brainstem, and spinal cord. Many hypotheses to explain the pathogenesis of ALS have been explored, but the exact mechanisms underlying the development of this disease remain unknown. However, abnormalities in MN excitability and glutamate excitotoxicity are the most widely studied. For decades, researchers have examined MN excitability in ALS, but the current literature is inconsistent, showing evidence of hyperexcitability, hypoexcitability, or no change in excitability of MNs in ALS. Many of these studies also focus …

Investigation Of Cation Exchange Behaviors Of FaXMa1-XPbl3 Films Using Dynamic Spin Coating, Hyang Mi Yu, Byeong Geun Jeong, Dae Young Park, Seong Chu Lim, Gon Namkoong, Mun Seok Jeong

Applied Research Center Publications

In this study, we fabricated and characterized uniform multi-cation perovskite FA_xMA_1−xPbI₃ films. We used the dynamic spin-coating method to control the cation ratio of the film by gradually increasing the FA+, which replaced the MA+ in the films. When the FA+ concentration was lower than xFA ~0.415 in the films, the stability of the multi-cation perovskite improved. Above this concentration, the film exhibited δ-phase FAPbI₃ in the FA_xMA_1−xPbI₃ films. The formation of δ-phase FAPbI₃ disturbed the homogeneity of the photoluminescence spatial distribution and suppressed the absorption spectral bandwidth …

Effect Of Hydrogen Co-Feeding On Ethylene Polymerization With Ziegler-Natta Catalysts With Different Amounts Of Titanium, Santhakamol Kittibanpacha

Chulalongkorn University Theses and Dissertations (Chula ETD)

Effect of hydrogen on the prepared TiCl4-MgCl2 catalysts having loading amounts of titanium was investigated via ethylene homopolymerization and ethylene/1-hexene copolymerization in slurry polymerization process. First, the catalysts were prepared to obtain different Ti loadings from 4.4 to 6.5 wt%. Then, all catalysts were characterized and tested in ethylene homopolymerization and ethylene/1-hexene copolymerization in the presence and absence of hydrogen during polymerization. It was found that hydrogen enhanced the catalyst activities on the catalyst with high Ti content (6.5 wt%) for 2.6 times and 1.9 times for ethylene homopolymerization and ethylene/1-hexene copolymerization, whereas it decreased the activity of the catalyst …

Simulation Of Flexural Performance Of Mill-Cut Steel Fiber Reinforced Concrete Beam Degraded By Mild Corrosion, Minh Khanh Vo

Chulalongkorn University Theses and Dissertations (Chula ETD)

The reinforced concrete structure is widely used for various applications structure due to its many advantages, so it is easily exposed to severe environments and corrosion of steel occurred shortening the life durable of the structure which may cause danger to humans and economic damage. Corrosion occurred as a significant factor leading to the further deterioration of performance and reduction of the loading resistance of reinforced concrete structures. Therefore, durable corroded structures should be dealt with to ensure user safety. In recent decades, steel fiber reinforced concrete is studied and applied cause of provides better durability. Nevertheless, there is a …

Surface Enhanced Raman Spectroscopy Analysis Of Thin-Smear-Contamination On Hdd Read-Write Head, Charin Seesomdee

Chulalongkorn University Theses and Dissertations (Chula ETD)

Surface-enhanced Raman spectroscopy (SERS) is one of the most powerful analytical techniques for the identification of molecules in microelectronics industry for failure analysis protocol. In this work, a dry-processed gold nanoclusters were prepared by magnetron sputtering deposition to promote the enhancement of the Raman signal for the best intensity gain from selected common polymers found in hard disk drive as surface contamination. The optimized sputtering conditions was applied for SERS on polycarbonate (PC), polyethylene terephthalate (PET), polypropylene (PP), and high-density polyethylene (HDPE). The Raman spectrum showed the average Raman signal intensity gain at about 114%, 78%, 254%, and 226% respectively. …

Communities Of Nitrifying Microorganisms From Recirculating Aquaculture Systems (Rass) Under Different Ammonium Concentration And Salinity, Preeyaporn Pornkulwat

Chulalongkorn University Theses and Dissertations (Chula ETD)

Bioaugmentation of nitrifying cultures can accelerate nitrification during startup and transition periods of recirculating aquaculture systems (RASs) operations. To formulate nitrifying cultures for RASs, impacts of ammonia and salinity (NaCl) on culturing nitrifying microorganisms were comprehensively investigated by including currently known groups of nitrifying microorganisms (ammonia-oxidizing archaea (AOA), ammonia oxidizing bacteria (AOB), comammox, Nitrospira, and Nitrobacter). Initially, community structure of nitrifying microorganisms was observed in biofilters from water recirculation units of shrimp holding tanks operated at two different salinities of 2 and 15 g/L. Unique patterns of nitrifying communities consisting of AOA, comammox, and Nitrospira (without AOB and Nitrobacter) were …

การจัดสมดุลสายการประกอบผลิตภัณฑ์ผสมแบบขนานหลายวัตถุประสงค์ที่ทำงานโดยคนงานและหุ่นยนต์, สุพิชชา งามพานิช

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในงานวิจัยนี้ได้เสนอวิธีแก้ปัญหาของการจัดสมดุลสายการประกอบผลิตภัณฑ์ผสมลักษณะขนาน ที่มีการดำเดินงานการประกอบผลิตภัณฑ์โดยหุ่นยนต์, คนงาน และคนงานผู้พิการ สำหรับสายการประกอบแบบขนาน เป็นระบบการประกอบที่ประกอบด้วยสายการประกอบเส้นตรงตั้งแต่ 2 สายการประกอบขึ้นไป ถูกนำมาจัดเรียงในแนวขนานกัน มีข้อดีคือ ทำให้สามารถลดรอบเวลาของสายการประกอบลงได้ โดยเฉพาะอย่างยิ่งในกรณีที่เวลาดำเนินงานของบางขั้นงานมีค่าสูงกว่ารอบเวลาที่ต้องการของสายการประกอบ ในงานวิจัยนี้มีวัตถุประสงค์ในการแก้ปัญหาของจัดสมดุลสายการประกอบ 5 วัตถุประสงค์ ได้แก่ 1) ประสิทธิภาพของสายการประกอบมากที่สุด 2) ปริมาณการปล่อยฝุ่น PM2.5 จากหุ่นยนต์เฉลี่ยมีค่าน้อยที่สุด 3) ความแตกต่างของภาระงานเฉลี่ยระหว่างสถานีงานน้อยที่สุด 4) ค่าความแปรปรวนจากการใช้พลังงานของพนักงานน้อยที่สุด 5) มูลค่าภาษีที่สามารถประหยัดได้จากการจ้างงานคนพิการมากที่สุด ซึ่งถือเป็นปัญหาแบบเอ็นพีแบบยาก (NP-hard) ทำให้เป็นไปได้ยากที่จะได้คำตอบที่ดีที่สุด (Optimal Solution) ในระยะเวลาที่จำกัด ดังนั้นจึงจะประยุกต์ใช้อัลกอริทึมวิธีการเชิงวิวัฒนาการแบบมากวัตถุประสงค์ ที่ถูกจัดว่าเป็นเมตาฮิวริสติก (Metaheuristic) ในการแก้ปัญหา, พัฒนาคำตอบ และค้นหาค่าที่ดีที่สุดพร้อมๆกันไปของแต่ละวัตถุประสงค์ โดยอัลกอริทึมที่จะศึกษาและทำการเปรียบเทียบประสิทธิภาพในการแก้ปัญหาของงานวิจัยนี้คือ วิธีการเชิงวิวัฒนาการแบบหลายวัตถุประสงค์โดยยึดหลักการจำแนก (MOEA/D) และ วิธีเชิงพันธุกรรมแบบการจัดลำดับที่ไม่ถูกครอบงำ III (NSGA-III) จากผลการเปรีบยเทียบตัวชี้วัดสมรรถนะของงานวิจัยแสดงให้เห็นว่า NSGA-III มีสมรรถนะที่ดีเหนือกว่า MOEA/D ในเกือบทุกโจทย์ปัญหา

Preference-Aware Task Assignment In Mobile Crowdsensing, Fatih Yucel

Theses and Dissertations

Mobile crowdsensing (MCS) is an emerging form of crowdsourcing, which facilitates the sensing data collection with the help of mobile participants (workers). A central problem in MCS is the assignment of sensing tasks to workers. Existing work in the field mostly seek a system-level optimization of task assignments (e.g., maximize the number of completed tasks, minimize the total distance traveled by workers) without considering individual preferences of task requesters and workers. However, users may be reluctant to participate in MCS campaigns that disregard their preferences. In this dissertation, we argue that user preferences should be a primary concern in the …

Pore Microstructure Impacts On Lithium Ion Transport And Rate Capability Of Thick Sintered Electrodes, Ziyang Nie, Rohan Parai, Chen Cai, Charles Michaelis, Jacob M. Lamanna, Daniel S. Hussey, David L. Jacobson, Dipankar Ghosh, Gary M. Koenig Jr.

Mechanical & Aerospace Engineering Faculty Publications

Increasing electrode thickness is one route to improve the energy density of lithium-ion battery cells. However, restricted Li⁺ transport in the electrolyte phase through the porous microstructure of thick electrodes limits the ability to achieve high current densities and rates of charge/discharge with these high energy cells. In this work, processing routes to mitigate transport restrictions were pursued. The electrodes used were comprised of only active material sintered together into a porous pellet. For one of the electrodes, comparisons were done between using ice-templating to provide directional porosity and using sacrificial particles during processing to match the geometric density …

A Geometric Description Of The Set Of Stabilizing Pid Controllers, Keqin Gu, Qian Ma, Huiqing Zhou, Mahzoon Salma, Xingzi Yang

SIUE Faculty Research, Scholarship, and Creative Activity

This article developed a new method to described the set of stabilizing PID control. The method is based on D-parameterization with natural description of the set. It was found that the stability crossing surface is a ruled surface that is completely determined by a curve known as discriminant. The discriminant is divided into sectors at the cusps. Corresponding to the sectors, the stability crossing surface is divided into positive and negative patches. A systematic study is conducted to identify the regions with a fixed number of right half-plane characteristic roots. The crossing directions of characteristic roots for positive patches and …

Raw And Pure Education In The Society, Iwasan D. Kejawa

Department of Educational Administration: Dissertations, Theses, and Student Research

What does education mean to individuals in the world today? Education is a way one can attain or improve his or her ability to lead and survive in the society of ours. Without educational training of the mind, it may be impossible to realize the importance of adaptability of living in the environment. Without education, It may also be difficult to embellish the use of both the mental and physical attributes possessed by individual beings.

What really is education? Education is the training of the mind to perform desire functions or to perpetuate the modality of obtaining an end or …

Applied Machine Learning In Extrusion-Based Bioprinting, Shuyu Tian

Theses and Dissertations

Optimization of extrusion-based bioprinting (EBB) parameters have been systematically conducted through experimentation. However, the process is time and resource-intensive and not easily translatable across different laboratories. A machine learning (ML) approach to EBB parameter optimization can accelerate this process for laboratories across the field through training using data collected from published literature. In this work, regression-based and classification-based ML models were investigated for their abilities to predict printing outcomes of cell viability and filament diameter for cell-containing alginate and gelatin composite hydrogels. Regression-based models were investigated for their ability to predict suitable extrusion pressure given desired cell viability when keeping …

General Brochure, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Highlights the Energy & Environmental Research Center’s employment, various resources for energy, fuel testing, technology development, and facilities. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]

Using A Lubricin Reporter Cell To Test Current Vs. Optimized Media Compositions, Sean M. Kennedy

Honors Undergraduate Theses

Osteoarthritis is a joint disease characterized by the breakdown of articular cartilage. The field of tissue engineering is interested in developing methods to produce biological alternatives to current orthopedic procedures. Lubricin is a molecule which is important in the proper lubrication of articular cartilage. It is a challenge in the field of tissue engineering to produce cartilage with sufficient lubricin expression. Developing a reporter cell for lubricin allowed for a more efficient investigation of the conditions wh­­­ich may influence its expression. By comparing "optimized" and traditional media solutions, it was determined that the use of a previously reported type II …

Bicycle Wheel Aerodynamics Predictions Using Cfd: Efficiency Using Blade Element Method, Drew Vigne

Honors Undergraduate Theses

The cycling industry has long relied on expensive wind tunnel testing when designing aerodynamic products, particularly in the context of wheels which account for 10 to 15 percent of a cyclist's total aerodynamic drag. With the recent advent of Computational Fluid Dynamics (CFD), the industry now has an economical tool to supplement the wheel design process; however, the complex nature of rotating spoked wheels requires high resolution meshes to model at acceptable fidelity. This research investigates an alternative CFD method that lowers the computational cost of modeling aerodynamic bicycle wheels by modeling spokes using Blade Element Method (BEM). Two CFD …

Workspace And Kinematic Modeling And Analysis Of Semi-Robotic Laparoscopic Surgery, Immanuel E. Girgis

Honors Undergraduate Theses

Laparoscopic Surgery has been revolutionized by the world of Surgical Robotics. Robot-Assisted Surgeries have been proven to have many advantages over the fundamental, traditional "by-hand" procedures previously conducted, and still currently being done for certain operations. Robot-assisted surgery may offer benefits to patients through the use of minimally invasive techniques, which may result in reduced blood loss, reduced blood transfusion, fewer complications, reduced postoperative pain, shorter hospital stays, and reduced recovery times (Ho et al., 2011). Studies have proven that robotic surgery may lead to patients recovering faster depending on the timeframe and the type of procedure (Tang et al., …

A Model For Assessing Staff Resilience To Improve Organizational Resilience In Emergency Departments, Stefani Baz

Honors Undergraduate Theses

Organizational Resilience is defined as the ability of an organization to anticipate sudden disruptions, effectively respond, and adapt in a changing environment to deliver its objectives, as well as successfully recover. In order to increase resilience at an organizational level, it is important to understand how individuals collectively contribute to resilience capability of an organization. Emergency Departments (EDs) are considered to be particularly well suited to investigating resilience capability due to their highly unpredictable and complex operating environment. Further, the resilience capability of EDs and their staff is suggested to be essential to successful delivery of safe, high-quality, and timely …

Development And Characterization Of Flow Independent Fuel Injectors, Michael W. Kwara

Honors Undergraduate Theses

Jet-in-crossflow is an interaction between a fuel jet and air crossflow commonly found in jet engines. The crossflow is used to break up or atomize the fuel jet for downstream combustion. This interaction between fluids while at low speeds, is predictable, varies greatly at higher speeds. This investigation seeks to (1) create a mechanism for jet-in-crossflow, using mechanical pintles, that is independent of velocity to help increase the predictability and reliability of jet engines and (2) identify key design parameters that will lead to flow independence. Parameters investigated in this experiment include pintle height, angle, and percent of pintle coverage …

Investigation Of Various Jet Configurations On Jet-In Crossflow Flame Characteristics At Elevated Pressures, Max K. Fortin

Honors Undergraduate Theses

The goal of this study is to investigate how varying the configuration of an axially staged combustion test facility affects the resultant flame and its relevant characteristics. Such relevant characteristics are the jet liftoff and the centerline jet trajectory. The configurations that are primarily being investigated are varied jet configuration diameters, 4mm and 12.7mm, preheated and non-preheated fuel, and different fuels. The testing facility is located at the University of Central Florida in the PERL (Propulsion and Energy Research Lab) facility. The facility allows for modeling an industrial turbine combustor, specifically an axial staged combustor with a Jet-In-Crossflow …

The Stability Of Two-Dimensional Cylinder Wakes In The Presence Of A Wavy Ground, Matt Duran

Honors Undergraduate Theses

The following study investigates hydrodynamic stability for two-dimensional, incompressible flow past a cylinder and compares it alongside four different variations of a wave-like ground introduced within the wake region of the cylinder wake. These different variations include changing the distance of the cylinder both horizontally from the wave-like structure and vertically from the ground. The geometry and meshes were initially constructed using GMSH and imported into Nektar++. The baseflows were then obtained in Nektar++ using the Velocity Correction Scheme, continuous Galerkin method, and Unsteady Navier Stokes solver. Then, the Implicitly Restarted Arnoldi Method driver was used to retrieve the various …

Development Of Lifting Line Theory For The Fanwing Propulsion System, Christopher Kaminski

Honors Undergraduate Theses

The FanWing propulsion system is a novel propulsion system which aerodynamically behaves as a hybrid between a helicopter and a fixed wing aircraft, and if the knowledge base with regards to this novel concept can be fully explored, there could be a new class of aircraft developed. In the current research, only 2D CFD studies have been done for the FanWing, hence the 3D lift characteristics of the FanWing have been unknown thus far, at least in the theoretical domain. Therefore, it was proposed to develop a modified Prandtl's Lifting Line Theory numerical solution and a CFD solution, comparing the …

Physicians And Their Patience: Redefining Healthcare Relationships Through Readability Optimization, Rachel V. Ball

Honors Undergraduate Theses

The present study takes legibility research and extends it to the medical setting. Internal Medicine Physicians from UCF developed six passages of medical text detailing a History of Present Illness (HPI) Report from an emergency department as well as comprehension questions for the purpose of our study. In our study, we first presented non-medical passages and comprehension questions in six common fonts to identify participants' individual fastest and slowest fonts. We then gave participants medical passages in both their best and worst fonts while measuring reading speed and comprehension. This study was delivered to a population of Amazon Mechanical Turk …

Solid Materia And Multiphase Detonations Wave Dynamics In A Rotating Detonation Engine, Ian Dunn

Electronic Theses and Dissertations, 2020-2023

Coal dust explosions can be hazardous; however, they can also generate a significant rise in stagnation pressure if adequately harnessed. Rotating detonation engine combustors seek to take advantage of the stagnation pressure rise phenomenon in a more sustained and controlled manner via confinement to a physical annulus, leading to increased overall thermodynamic efficiency. This investigation presents an analysis of detonations fueled by Carbon Black, a solid particulate consisting of virtually pure carbon molecules and lean Hydrogen-Air mixtures. As was previously realized with the addition of Carbon Black, an increase of operability limits and detonation velocities over that of a pure …

Monitoring Of Microscopic Traffic Behavior For Safety Applications Using Temporal Logic, Mariam Wessam Hassan Mohamed Nour

Electronic Theses and Dissertations, 2020-2023

Smart cities are revolutionizing the transportation infrastructure by the integration of technology. However, ensuring that various transportation system components are operating as expected and in a safe manner is a great challenge. One of the proposed solutions is traffic monitoring systems which collect and analyze traffic data for the safe operation and management of the overall system. Even though traffic safety analysis has been tied to crash data, surrogate safety measures (SSM) have recently emerged as a replacement. SSM can provide a convenient alternative for understanding the impact of conflicts on overall road safety. Traditionally, conflicts were studied through manual …

Mechanically Reconfigurable Materials And Devices Based On Two-Dimensional Transition Metal Dichalcogenide Layers, Emmanuel Okogbue

Electronic Theses and Dissertations, 2020-2023

The recent advances in electronic technologies are geared towards a combination of continued miniaturization in device components and their integration onto unconventional platforms. These efforts are aimed towards achieving electronic devices with various form factors and novel functionalities which are unattainable from traditional devices. Among these envisioned 'futuristic' technologies, electronic devices which are mechanically reconfigurable and operable under harsh operational conditions in the form of stretching, twisting and folding offer tremendous amount of unparalleled opportunities. This dissertation studies two-dimensional (2D) transition metal dichalcogenide (TMDs), a distinct class of materials with peculiar optical, electrical and mechanical properties for mechanically reconfigurable electronics. …

Secure And Trustworthy Hardware And Machine Learning Systems For Internet Of Things, Shayan Taheri

Electronic Theses and Dissertations, 2020-2023

The advancements on the Internet have enabled connecting more devices into this technology every day. This great connectivity has led to the introduction of the internet of things (IoTs) that is a great bed for engagement of all new technologies for computing devices and systems. Nowadays, the IoT devices and systems have applications in many sensitive areas including military systems. These challenges target hardware and software elements of IoT devices and systems. Integration of hardware and software elements leads to hardware systems and software systems in the IoT platforms, respectively. A recent trend for the hardware systems is making them …

Low-Profile Wireless Passive Temperature Sensors, Ectis Velazquez

Electronic Theses and Dissertations, 2020-2023

This thesis explores design challenges and promising solutions for temperature sensors for high temperature environments such as combustion turbines. To survive this high temperature environment of over 1000 °C the sensors are required to be robust in their electrical and mechanical properties. Wire connections for these high temperature environments are a complex problem due to the physical limitations of most materials at those high temperatures. In this thesis, robust ceramic sensors based on microwave resonators are demonstrated for high temperature environments, with some studies into optimizing the techniques used to measure them, as well as the distance at which their …

Robust Acceleration Of Data-Centric Applications Using Resistive Computing Systems, Baogang Zhang

Electronic Theses and Dissertations, 2020-2023

With the accessible data reaching zettabyte level, CMOS technology is reaching its limit for the data hungry applications. Moore's law has been reaching its depletion in recent studies. On the other hand, von Neumann architecture is approaching the bottleneck due to the data movement between the computing and memory units. With data movement and power budgets becoming the limiting factors of today's computing systems, in-memory computing using emerging non-volatile resistive devices has attracted an increasing amount of attention. A non-volatile resistive device may be realized using memristor, resistive random access memory (ReRAM), phase change memory (PCM), or spin-transfer torque magnetic …

Analysis Of Sign Language Facial Expressions And Deaf Students' Retention Using Machine Learning And Agent-Based Modeling, Marie Alaghband

Electronic Theses and Dissertations, 2020-2023

There are currently about 466 million people worldwide who have a hearing disability, and that number is expected to increase to 900 million by 2050. About 15% of adult Americans have hearing disabilities and about every three in 1,000 U.S. children are born with hearing loss in one or both ears. The World Health Organization (WHO) estimates that unaddressed hearing loss poses an annual global cost of $980 billion, including cost of educational support, loss of productivity, and societal costs. These are all evident that people with hearing loss are experiencing several kinds and levels of difficulties. In this dissertation, …

Experimental And Chemical Kinetics Investigation Of High-Temperature Combustion Of Diisopropyl Methylphosphonate., Ramees Khaleel Rahman

Electronic Theses and Dissertations, 2020-2023

Due to the high toxicity of chemical warfare (CW) agents, laboratory experiments are carried out using CW surrogates. Diisopropyl Methylphosphonate (DIMP), an organophosphate compound (OPC), is a crucial CW surrogate that has a chemical structure like the deadly nerve agent Sarin (GB). In this work, high-temperature combustion of DIMP is studied in a shock tube to understand the kinetics of destruction of DIMP. Laser absorption spectroscopy was used to obtain carbon monoxide mole fraction time-histories during high-temperature combustion of DIMP. Since combustion involves complex mixing phenomena involving different fuel to oxidizer ratios, experiments were conducted at conditions relevant to a) …