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Articles 31 - 60 of 96
Full-Text Articles in Engineering
Structural Characteristics And Thermophysical Properties Of Molten Salts From Ab Initio Molecular Dynamics Simulations, Austin David Clark
Structural Characteristics And Thermophysical Properties Of Molten Salts From Ab Initio Molecular Dynamics Simulations, Austin David Clark
Theses and Dissertations
This work 1) draws insights on molten salt structure and properties directly from ab initio molecular dynamics (AIMD) simulations, 2) demonstrates the advantageous symbiosis of computational and experimental collaborations on molten salt research, and 3) simultaneously generates ab initio data sets for fitting an interatomic potential model for classical molecular dynamics (MD) simulations. This work discusses the motivations for AIMD simulations of molten salts, thermophysical properties and structural characteristics of interest, advanced methodologies for AIMD simulations, and several completed AIMD studies on molten salts. Of import are the methodological contributions of this work to AIMD simulations, primarily the radical increase …
The Abacus: A New Approach To Authorization, Jacob Aaron Jess Siebach
The Abacus: A New Approach To Authorization, Jacob Aaron Jess Siebach
Theses and Dissertations
The purpose of this thesis is to investigate the implementation of digital authorization for computer systems, specifically how to implement an efficient and secure authorization engine that uses policies and attributes to calculate authorization. The architecture for the authorization engine is discussed, the efficiency of the engine is characterized by various tests, and the security model is reviewed against other presently existing models. The resulting efforts showed an increase in efficiency of almost two orders of magnitude, along with a reduction in the amount of processing power required to run the engine. The main focus of the work is how …
Designing Cell-Free Protein Synthesis Systems For Improved Biocatalysis And On-Demand, Cost-Effective Biosensors, Mehran Soltani Najafabadi
Designing Cell-Free Protein Synthesis Systems For Improved Biocatalysis And On-Demand, Cost-Effective Biosensors, Mehran Soltani Najafabadi
Theses and Dissertations
The open nature of Cell-Free Protein Synthesis (CFPS) systems has enabled flexible design, easy manipulation, and novel applications of protein engineering in therapeutic production, biocatalysis, and biosensors. This dissertation reports on three advances in the application of CFPS systems for 1) improving biocatalysis performance in industrial applications by site-specific covalent enzyme immobilization, 2) expressing and optimizing a difficult to express a mammalian protein in bacterial-based CFPS systems and its application for cost-effective, on-demand biosensors compatible with human body fluids, and 3) streamlining the procedure of an E. coli extract with built-in compatibility with human body fluid biosensors. Site-specific covalent immobilization …
Transparent Capacitive And Piezoelectric Micromachined Ultrasonic Transducers For Tactile Feedback With 3d Displays, Emily Anne Laughlin
Transparent Capacitive And Piezoelectric Micromachined Ultrasonic Transducers For Tactile Feedback With 3d Displays, Emily Anne Laughlin
Theses and Dissertations
3D display technology is limited by the user's ability to interact with displays without being connected to external equipment. In order to feel tactile feedback in conjunction with displays, ultrasonic sound pressure fields have been created; however, ceramic transducers interfere with the user's immersive experience. We have created transparent ultrasonic transducers using capacitive micromachined ultrasonic transducer (CMUT) and piezoelectric micromachined ultrasonic transducer (PMUT) technology that allow the user to remain immersed in the experience while interacting with the display. Individual transparent piezoelectric transducers made with indium tin oxide (ITO) and polyvinylidene fluoride (PVDF) generate 66.9dB with 91.6% transparency. Samples were …
Active Thermography For Additive Manufacturing Processes, Nicholas Jay Wallace
Active Thermography For Additive Manufacturing Processes, Nicholas Jay Wallace
Theses and Dissertations
The goal of the research conducted for this master's thesis is to understand if active thermography is a suitable technique to detect (identify) and measure (approximate depth and or size) defects in additive manufacturing (AM) processes. Although other non-destructive measurement techniques exist, active thermography is an attractive option for AM applications because of the short measurement times that could be implemented between each layer of a print, and because of the relatively inexpensive equipment required. However, pulse thermography is typically applied to detect larger defects (>1 mm) in materials with high thermal conductivity. It was uncertain if active thermography …
An Investigation Of The Impact Gender-Specific Course Grouping Has On Female Middle-School Students' Concept Of And Interests Toward Technology And Engineering, Thomas Broderick Walsh
An Investigation Of The Impact Gender-Specific Course Grouping Has On Female Middle-School Students' Concept Of And Interests Toward Technology And Engineering, Thomas Broderick Walsh
Theses and Dissertations
Attempts to improve retention, interest, and enrollment of females in Technology & Engineering Education courses have included a variety of approaches including female-only classes. However, the implications of such courses have not been thoroughly investigated. Therefore, an investigation of female-only classes was undertaken; the findings revealed that the overall enrollment of females went up in the course and in subsequent classes, these students maintained their interests and attitudes towards Technology and Engineering, their perceptions of an engineer's gender changed from that of mostly male to mostly female, and their concepts of what an engineer does changed from mostly building or …
Analysis Of Closed-Loop Digital Twin, Andrew Stuart Eyring
Analysis Of Closed-Loop Digital Twin, Andrew Stuart Eyring
Theses and Dissertations
Given recent advancements in technology and recognizing the evolution of smart manufacturing, the implementation of digital twins for factories and processes is becoming more common and more useful. Additionally, expansion in connectivity, growth in data storage, and the implementation of the Industrial Internet of Things (IIoT) allow for greater opportunities not only with digital twins but closed loop analytics. Discrete Event Simulation (DES) has been used to create digital twins and in some instances fitted with live connections to closely monitor factory operations. However, the benefits of a connected digital twin are not easily quantified. Therefore, a test bed demonstration …
Analysis Of Benefits Of An Expansion To Udot's Incident Management Program, Logan Stewart Bennett
Analysis Of Benefits Of An Expansion To Udot's Incident Management Program, Logan Stewart Bennett
Theses and Dissertations
In 2018 the Utah Department of Transportation (UDOT) funded a study in which data were collected to evaluate performance measures for UDOT's Incident Management Team (IMT) program. After that study was completed, UDOT received funding to expand the size of its IMT program. Additionally, TransSuite, a data source used by the UDOT Traffic Operations Center to log incident-related data, was reconfigured to provide a higher quantity of performance measure data. This study made use of the new data source, in addition to Computer Aided Dispatch logs provided by the Utah Highway Patrol that were used in the first study, to …
Highly Integrated And Miniaturized 3d Printed Serial Dilution Microfluidic Devices For Dose-Response Assays, Jose Luis Sanchez Noriega
Highly Integrated And Miniaturized 3d Printed Serial Dilution Microfluidic Devices For Dose-Response Assays, Jose Luis Sanchez Noriega
Theses and Dissertations
The ability to generate a range of concentrations of various solutions rapidly and conveniently is an ongoing need in biotechnology. In this thesis we demonstrate how we took advantage of the full process control afforded by our recent custom high resolution 3D printer and resin advances to realize highly integrated and miniaturized microfluidic components for simultaneous on-chip serial dilution for dose-response assays. With judicious selection of mixed layer thicknesses and pixel-by-pixel dose control, we show that the diameter of 3D printed membrane valves can be reduced from 300 µm to 46 µm. We further introduce an entirely new kind of …
Forecasting Inundation Extents In The Amazon Basin Using Srh-2d And Hand Based On The Geoglows Ecmwf Streamflow Services, Christopher Hyde Edwards
Forecasting Inundation Extents In The Amazon Basin Using Srh-2d And Hand Based On The Geoglows Ecmwf Streamflow Services, Christopher Hyde Edwards
Theses and Dissertations
Floods are the most impactful natural disasters on earth, and reliable flood warning systems are critical for disaster preparation, mitigation, and response. The GEOGloWS ECMWF Streamflow Services (GESS) provide forecasted streamflow throughout the world. While forecasted discharge is essential to flood warning, forecasted inundation extents are required to understand and predict flood impact. In this research, I sought to expand GESS flood warning potential by generating inundation extents from streamflow forecasts. I compared Height Above Nearest Drainage (HAND), a method beneficial for flood mapping on a watershed scale, to a 2D hydrodynamic model, specifically Sedimentation and River Hydraulics – Two …
Feasibility And Impact Of Liquid/Liquid-Encased Dopants As Method Of Composition Control In Laser Powder Bed Fusion, Taylor Matthew Davis
Feasibility And Impact Of Liquid/Liquid-Encased Dopants As Method Of Composition Control In Laser Powder Bed Fusion, Taylor Matthew Davis
Theses and Dissertations
Additive manufacturing (AM) – and laser powder bed fusion (LPBF) specifically – constructs geometry that would not be possible using standard manufacturing techniques. This geometric versatility allows integration of multiple components into a single part. While this practice can reduce weight and part count, there are also serious drawbacks. One is that the LPBF process can only build parts with a single material. This limitation generally results in over-designing some areas of the part to compensate for the compromise in material choice. Over-designing can lead to decreased functional efficiency, increased weight, etc. in LPBF parts. Methods to control the material …
Concepts For Rapid-Refresh, Global Ocean Surface Wind Measurement Evaluated Using Full-System Parametric Extrema Modeling, M. Patrick Walton
Concepts For Rapid-Refresh, Global Ocean Surface Wind Measurement Evaluated Using Full-System Parametric Extrema Modeling, M. Patrick Walton
Theses and Dissertations
Satellite wind vector data is integral to atmospheric models and forecasts. Currently, the limited refresh rate of global wind vector measurement systems makes it difficult to observe diurnal variation of mesoscale processes. Using advancements in the underlying subsystem technologies, new satellite wind scatterometers may be possible that increase temporal resolution, among other performance metrics. I propose a method for parametrically modeling the extreme performance range of a complex system. I use this method to develop a model of the space of possible satellite wind scatterometer designs. I validate the model using point designs of heritage scatterometers. Finally, I present two …
Considering Social Impact When Engineering For Global Development, Hans Jorgen Ottosson
Considering Social Impact When Engineering For Global Development, Hans Jorgen Ottosson
Theses and Dissertations
Every manufactured product has an environmental impact, a social impact, and an economic impact. As engineers, we should do our best to understand how our design decisions influence these impacts (the three pillars of sustainability), and at the same time make decisions that collectively lead to maximum positive impacts, or minimum negative impacts on the economy, environment, and society. Many times, engineers show interest and want to design for all three pillars of sustainability but are often constrained to focus on the environmental and economic aspects, leaving out social sustainability due to lack of understanding and resources. In practice, this …
Dual-Axis Acousto-Optic/Electro-Optic Deflectors In Lithium Niobate For Full-Parallax Holographic Video Displays, Mitchell Robert Adams
Dual-Axis Acousto-Optic/Electro-Optic Deflectors In Lithium Niobate For Full-Parallax Holographic Video Displays, Mitchell Robert Adams
Theses and Dissertations
A major limitation of acousto-optic (AO) leaky-mode modulator based holographic displays is their inability to present full-parallax. We propose that full-parallax capabilities can be bestowed on these displays by integrating an electro-optic (EO) phased array into the architecture. We validated this concept by rendering computational models and by fabricating and testing a basic two-axis AO/EO deflector prototype in lithium niobate. This was, to our knowledge, the first instantiation of an integrated, hybrid AO/EO deflector. The prototype had a 6° deflection range along the AO-axis, and a 3° deflection range along the EO-axis. A series of models provide us with a …
Assessment And Expansion Of Laboratory-Based Testing Of Biomass Cookstoves, Cameron M. Quist
Assessment And Expansion Of Laboratory-Based Testing Of Biomass Cookstoves, Cameron M. Quist
Theses and Dissertations
Biomass cookstoves are a significant source of various pollutants, such as CO2, CO, and particulate matter (PM). To mitigate the issues surrounding cookstoves, significant research has been undertaken on improved cookstoves (ICS). This research can be performed in a laboratory setting, in the field, or a combination of both. This work concentrates on the purely laboratory testing. Laboratory testing has both advantages and disadvantages when compared to field testing (e.g. decreased cost and increased consistency). However, field applications are variable, environments can be significantly different (for example wind and ambient temperature can be very different in the field vs. a …
Ductile Design And Predicted Inelastic Response Of Steel Moment Frame Buildings For Extreme Wind Loads, Tyler Eric Giles
Ductile Design And Predicted Inelastic Response Of Steel Moment Frame Buildings For Extreme Wind Loads, Tyler Eric Giles
Theses and Dissertations
Inelastic design methods have been used in seismic design for several years and are well accepted in engineering practice. In contrast, an inelastic wind design method is yet to be developed, in part due to the inherent differences between seismic forces and wind forces. Current wind design practice follows a linear method to find a design windspeed for the location where the structure will be built. Once the design windspeed has been determined, the lateral force resisting system is designed such that it will behave elastically. This study was conducted with the hypothesis that by providing ductility at the material …
Cmos Charge Amplifier For Scientific Instruments, Yixin Song
Cmos Charge Amplifier For Scientific Instruments, Yixin Song
Theses and Dissertations
Charge detection is essential for a large number of commercial and scientific applications. A charge amplifier is one of the most fundamental building blocks for a detector system. This thesis describes the design, circuit implementation, and post-silicon testing of two different charge amplifier designs, analog and digital, that address some commonly seen fundamental challenges in the charge detection application. In particular, the proposed designs can be integrated with an image charge detector (ICD) to study the characteristics of dust on Mars. The proposed charge amplifier design utilizes a small 10 fF feedback capacitor to achieve a high gain. The fully …
Design Validation Of A Multi-Stage Gradually Deploying Stent, Dillon J. Despain
Design Validation Of A Multi-Stage Gradually Deploying Stent, Dillon J. Despain
Theses and Dissertations
Angioplasty, or the use of rapidly deploying stents, is a common treatment for reopening narrowed vasculature often caused by atherosclerotic plaque. However, in-stent restenosis (ISR) induced by intimal hyperplasia is a common challenge to angioplasty. High impact stresses from current stent deployment processes have been linked to intimal hyperplasia; thus a stent that is gradually deployed over a longer period of time holds potential to mitigate these stresses. This work hypothesizes that resorbable polymeric links can be used as a triggering mechanism to enable repeatably controlled deployment of a compliant nitinol stent design with the eventual goal of reducing intimal …
Modeling Current And Future Windblown Utah Dust Events Using Cmaq 5.3.1, Zachary David Lawless
Modeling Current And Future Windblown Utah Dust Events Using Cmaq 5.3.1, Zachary David Lawless
Theses and Dissertations
Windblown dust events can be defined as windblown dust emitted from the Earth's surface to the atmosphere. These events have significant impact on local air quality. Predicting the location and magnitude of these events is vital for Utah air quality assessment and planning. Previous modeling studies have focused only on past dust events. This work utilized a state-of-the-science software framework based on the Community Multiscale Air Quality (CMAQ) v5.3.1 modeling system to predict dust events in Utah. The framework was verified using previous studies for dust events in April 2017 and March 2010. Once verified, the framework was used to …
Control Of Post-Weld Fracture Toughness In Friction Stir Processed X-80 Hsla Steel, Nolan Tracy Crook
Control Of Post-Weld Fracture Toughness In Friction Stir Processed X-80 Hsla Steel, Nolan Tracy Crook
Theses and Dissertations
The present study investigates the fracture toughness of FSW X-80 HSLA steel welds. Weld cooling rate and peak temperature were varied among welds; indirectly manipulated through FSW travel speed, rpm, and weld preheat. Fracture toughness was tested according to ASTM 1820 standard along the weld centerline using surface-notched SEB specimen cooled to -40 °C. This study resulted in a reliable, repeatable process for generating friction stir welds with CTOD’s consistently above that of the original base metal. CTOD and microstructure of friction stir welds can be selected by controlling weld cooling rate and peak temperature. Material properties and microstructure similar …
Use Of Vertical Electrical Impedance For Nondestructive Evaluation Of Concrete Bridge Decks, Enoch Thomas Boekweg
Use Of Vertical Electrical Impedance For Nondestructive Evaluation Of Concrete Bridge Decks, Enoch Thomas Boekweg
Theses and Dissertations
Nondestructive evaluation of civil infrastructure is increasingly important in the modern world to assess structures, predict longevity, and prescribe rehabilitation or replacement. For concrete bridge decks, one emerging diagnostic technique is vertical electrical impedance (VEI) testing, which is a nondestructive evaluation technology that quantitatively assesses the cover protection offered to steel reinforcement. Because VEI testing is still a relatively new approach to bridge deck inspection, additional studies are needed to increase the interpretability of VEI data. This thesis increases VEI interpretability with two advances. The first advance, presented in Chapter 2, offers an analytical model for interpreting VEI measurements of …
Exploration Of Constant-Force Wristbands For A Wearable Health Device, Thomas Alexander Naylor
Exploration Of Constant-Force Wristbands For A Wearable Health Device, Thomas Alexander Naylor
Theses and Dissertations
Wearable Health Devices (WHDs) are an emerging technology that enables continuous monitoring of vital signs during daily life. Issues with constant and consistent data acquisition have been found while WHD technology has developed. The force of the measurement area and movement of the sensors are key mechanical issues that need to be solved for WHDs to become a viable way to continuously monitor health conditions. This work explores Constant-Force Mechanisms (CFMs) as a solution to problems the current WHD industry faces. Additionally, the relationship between force provided from the mechanism, sensor pressure on the wrist, patient comfort, and sensor readings …
An Exploration Of Soil Moisture Reconstruction Techniques, Spencer Nishimoto Low
An Exploration Of Soil Moisture Reconstruction Techniques, Spencer Nishimoto Low
Theses and Dissertations
Satellite radiometers are used to remotely measure properties of the Earth's surface. Radiometers enable wide spatial coverage and daily temporal coverage. Radiometer measurements are used in a wide array of applications, including freeze/thaw states inference, vegetation index calculations, rainfall estimation, and soil moisture estimation. Resolution enhancement of these radiometer measurements enable finer details to be resolved and improve our understanding of Earth. The Soil Moisture Active Passive (SMAP) radiometer was launched in April 2014 with a goal to produce high resolution soil moisture estimates. However, due to hardware failure of the radar channels, prepared algorithms could no longer be used. …
Precision Maritime Landing Of Autonomous Multirotor Aircraft With Real-Time Kinematic Gnss, Matthew Kent Rydalch
Precision Maritime Landing Of Autonomous Multirotor Aircraft With Real-Time Kinematic Gnss, Matthew Kent Rydalch
Theses and Dissertations
In this thesis two methods were developed for precise maritime landing of an autonomous multirotor aircraft based on real-time kinematic (RTK) Global Navigation Satellite System (GNSS). The first method called RTK-localized method (RLM) uses RTK GNSS measurements to localize a sea vessel and execute the landing. RLM was demonstrated outdoors in hardware and landed on a physically simulated boat called a mock-boat with an average landing error of 9.7 cm. The mock-boat was actuated to have boat-like motion and a forward velocity of ~2 m/s. This method showed that accurate landing is possible with RTK GNSS as the primary means …
A New Method Of Measuring Flow Stress For Improved Modeling Of Friction Stir Welding, David John Prymak
A New Method Of Measuring Flow Stress For Improved Modeling Of Friction Stir Welding, David John Prymak
Theses and Dissertations
Deficiencies in friction stir welding (FSW) numerical modelling are identified. Applicability of flow stress data derived from hot compression, hot torsion, and split Hopkinson bar testing methods is assessed. A new method of measuring flow stresses in the stir zone of a friction stir welding tool is developed. This test utilizes a non-consumable flat-faced cylindrical tool of different geometries that induces a vertical and rotational load on the material of interest. A constant vertical load and rpm value is used for each test yielding the resulting motor torque and temperature generation to define the material response. Experimental samples are cross-sectioned, …
Zero-Energy Tuning Of Silicon Microring Resonators Using 3d Printed Microfluidics And Two-Photon Absorption Induced Photoelectrochemical Etching Of Silicon, Kevin Eugene Larson
Zero-Energy Tuning Of Silicon Microring Resonators Using 3d Printed Microfluidics And Two-Photon Absorption Induced Photoelectrochemical Etching Of Silicon, Kevin Eugene Larson
Theses and Dissertations
This thesis presents a novel method of modulating silicon photonic circuits using 3D printed microfluidic devices. The fluids that pass through the microfluidic device interact directly with the silicon waveguides. This method changes the refractive index of the waveguide cladding, thus changing the effective index of the system. Through using this technique we demonstrate the shift in resonant wavelength by a full free spectral range (FSR) by increasing the concentration of the salt water in the microfluidic device from 0% to 10%. On a 60 μm microring resonator, this equals a resonant wavelength shift of 1.514 nm when the index …
High-Speed Image Classification For Resource-Limited Systems Using Binary Values, Taylor Scott Simons
High-Speed Image Classification For Resource-Limited Systems Using Binary Values, Taylor Scott Simons
Theses and Dissertations
Image classification is a memory- and compute-intensive task. It is difficult to implement high-speed image classification algorithms on resource-limited systems like FPGAs and embedded computers. Most image classification algorithms require many fixed- and/or floating-point operations and values. In this work, we explore the use of binary values to reduce the memory and compute requirements of image classification algorithms. Our objective was to implement these algorithms on resource-limited systems while maintaining comparable accuracy and high speeds. By implementing high-speed image classification algorithms on resource-limited systems like embedded computers, FPGAs, and ASICs, automated visual inspection can be performed on small low-powered systems. …
Behavior Of Unreinforced Lightweight Cellular Concrete Backfill For Reinforced Concrete Retaining Walls, Ryan Jeffrey Wilkinson
Behavior Of Unreinforced Lightweight Cellular Concrete Backfill For Reinforced Concrete Retaining Walls, Ryan Jeffrey Wilkinson
Theses and Dissertations
Lightweight cellular concrete (LCC) is a mixture of cement, water and foam, with a density less than 50 pcf. This material is being used increasingly often in a variety of construction applications due to its self-leveling, self-compacting, and self-consolidating properties. LCC may be used as a backfill or structural fill in areas where traditional granular backfill might normally be used. This material may be especially advantageous in areas where the underlying soil may not support the weight of a raised earth embankment. Testing on the behavior of LCC when used as backfill behind retaining walls is relatively limited. The effects …
Understanding Quote-Tweet Usage During The Covid-19 Pandemic, David Hardy Bean
Understanding Quote-Tweet Usage During The Covid-19 Pandemic, David Hardy Bean
Theses and Dissertations
The Covid-19 pandemic first entered the international news cycle with mixed levels of concern. How did people across the globe react to first encounters with this virus? For many it was like seeing for the first time the spewing ash of a volcano, or the receding tides of a tsunami. Many reacted with disbelief, not knowing the proper course of action for themselves or for their community. This study explores the topics of discussion and reactions to the pandemic through the lens of quote-tweets--from the initial confusion and disbelief to the eventual politicization, economic closures, and reopening events. Quote-tweets are …
A Framework For Assessing And Designing Human Annotation Practices In Human-Ai Teaming, Suzanne Ashley Stevens
A Framework For Assessing And Designing Human Annotation Practices In Human-Ai Teaming, Suzanne Ashley Stevens
Theses and Dissertations
This thesis work examines how people accomplish annotation tasks (i.e., labelling data based on content) while working with an artificial intelligence (AI) system. When people and AI systems work together to accomplish a task, this is referred to as human-AI teaming. This study reports on the results of an interview and observation study of 15 volunteers from the Washington DC area as the volunteers annotated Twitter messages (tweets) about the COVID-19 pandemic. During the interviews, researchers observed the volunteers as they annotated tweets, noting any needs, frustrations, or confusion that the volunteers expressed about the task itself or when working …