Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Portland State University

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 691 - 720 of 2758

Full-Text Articles in Engineering

Determinants Of Student Information Technology Adoption, Hans P. Vanderschaaf Jul 2020

Determinants Of Student Information Technology Adoption, Hans P. Vanderschaaf

Dissertations and Theses

Innovating service delivery in higher education is central to supporting institutional and societal goals of increasing the numbers of college graduates and for transforming higher education institutions to center on the needs of today's students. Within this context, technology plays a critical role. This research seeks to contribute to institutional, academic and educational technology sector efforts to dramatically enhance service quality, in support of improving undergraduate student outcomes (student success), by identifying the determinants of student information technology adoption and removing barriers to accessing higher education.

Using a mixed-methods and empirical approach based on the Unified Theory of Acceptance and …


Statistical Modeling Of Historical Daily Water Temperatures In The Lower Columbia River, Malia Hanae Scott Jul 2020

Statistical Modeling Of Historical Daily Water Temperatures In The Lower Columbia River, Malia Hanae Scott

Dissertations and Theses

Water temperature affects numerous aspects of aquatic life, and its stability is critical to cold water fish such as salmonids. With rising anthropogenic influence in natural environments, the future existence of these organisms is becoming less certain. In this study, I examined the evolution of historical water temperatures in the lower Columbia River by creating a statistical model to estimate daily historical water temperatures between the 1850s and 2010s. Daily air temperature and river flow measurements were used as inputs to the model, which estimated daily water temperatures at Bonneville Dam. The model used time lags between air temperature and …


Dynamic Effects Of Inertial Particles On The Wake Recovery Of A Model Wind Turbine, Sarah E. Smith Jul 2020

Dynamic Effects Of Inertial Particles On The Wake Recovery Of A Model Wind Turbine, Sarah E. Smith

Dissertations and Theses

Impacting particles such as rain, dust, and other debris can have devastating structural effects on wind turbines, but little is known about the interaction of such debris within turbine wakes. This study aims to characterize behavior of inertial particles within the turbulent wake of a wind turbine and relative effects on wake recovery. Here a model wind turbine is subjected to varied two-phase inflow conditions, with wind as the carrier fluid (Reλ = 49 - 88) and polydisperse water droplets (26 to 45µm in diameter) at varied concentrations (Φv=0.24 x 10-5 - 1.3 …


Exploring Policies And Strategies For The Diffusion Of Remote Patient Monitoring (Rpm) For The Care Of Senior Population, Hamad Asri Alanazi Jul 2020

Exploring Policies And Strategies For The Diffusion Of Remote Patient Monitoring (Rpm) For The Care Of Senior Population, Hamad Asri Alanazi

Dissertations and Theses

Telemedicine offers great promise in addressing some of the healthcare challenges such as the increase of healthcare expenditure, a growing population, and a projected physician shortage; telemedicine is increasingly being included in the discussion of medicine's future. Telemedicine offers the capabilities to deliver healthcare across distances at reduced costs while maintaining or even increasing the quality of treatment and services.

The objective of this research is to develop a model to evaluate alternative solutions to increase the adoption of RPM for the senior population. Also, the research provides a systematic approach for a comprehensive assessment of teleconsultation adoption, develop a …


Droplet Ejections During Wet Lab Operations Aboard Spacecraft, Caleb Cushman Turner Jul 2020

Droplet Ejections During Wet Lab Operations Aboard Spacecraft, Caleb Cushman Turner

Dissertations and Theses

The breakup and rupture of liquid bridges, thin films, bubbles, droplets, rivulets, and jets can produce satellite droplets that are subsequently ejected into their surrounding environment. For example, when any solid object is withdrawn from a liquid bath, the formation of an ever-thinning columnar liquid bridge eventually ruptures along the axis of the bridge. When rupture occurs under typical pipetting conditions the dynamics governing the rupture almost always produce at a minimum a satellite droplet. When these droplets occur they are often too small and too fast to be observed by the human eye. In a terrestrial environment they are …


Evaluating R&D Projects In Regulated Utilities: The Case Of Power Transmission Utilities, Edwin Garces Jul 2020

Evaluating R&D Projects In Regulated Utilities: The Case Of Power Transmission Utilities, Edwin Garces

Dissertations and Theses

R&D project selection is essential for many organizations; however, it is a complex decision since it is affected by many factors. These factors vary among organizations because of their different objectives and conditions. There are limited budgets for the investments, and the current R&D project selection methods are focused on financial analysis or complex mathematical probabilistic calculations. Therefore, the main motivation of this research is to create a method to help improve the ex-ante selection of R&D projects in regulated organizations. More importantly, the case application is the electric transmission utilities sector, which plays one of the most critical roles …


Memristive Architectures And Algorithms For Approximate Graph-Based Inference, Mohammad M.A. Taha Jul 2020

Memristive Architectures And Algorithms For Approximate Graph-Based Inference, Mohammad M.A. Taha

Dissertations and Theses

The goal of this thesis is to design fast, low-power, robust graph-based inference systems. Our approach to this is by using (1) in-memory computing, (2) approximate computing principles, and (3) memristive devices.

This work is motivated by the fact that conventional von Neumann architectures are not efficient for inference applications, mainly due to the data transfer bottleneck. Adding cache memories and using GPUs is a remedy, however, does not eliminate this bottleneck. In-memory computing is an alternative approach that performs all computations inside the memory, thus eliminating the data transfer bottleneck.

The memristor, which is a passive two-terminal device, is …


A Market Diffusion Potential (Mdp) Assessment Model For Residential Energy Efficient (Ee) Technologies In The U.S., Momtaj Khanam Jul 2020

A Market Diffusion Potential (Mdp) Assessment Model For Residential Energy Efficient (Ee) Technologies In The U.S., Momtaj Khanam

Dissertations and Theses

The Diffusion of Residential Energy Efficient (EE) Technologies has been studied for many years. Finding ways to bridge the energy efficiency gap and increase the diffusion of these technologies have been of much interest to researchers and practitioners alike. However, in most studies, diffusion is equated to adoption of EE technologies by consumers. The present study tries to break this mindset and develops a model to assess the diffusion of residential EE technologies from the market's perspective. The model assesses diffusion of an EE technology based on the market's ability to provide benefits to customers that are identified to be …


The Optimization Of Machining Parameters For Milling Operations By Using The Nelder–Mead Simplex Method, Yubin Lee, Alin Resiga, Sung Yi, Chien Wern Jul 2020

The Optimization Of Machining Parameters For Milling Operations By Using The Nelder–Mead Simplex Method, Yubin Lee, Alin Resiga, Sung Yi, Chien Wern

Mechanical and Materials Engineering Faculty Publications and Presentations

The purpose of machining operations is to make specific shapes or surface characteristics for a product. Conditions for machining operations were traditionally selected based on geometry and surface finish requirements. However, nowadays, many researchers are optimizing machining parameters since high-quality products can be produced using more expensive and advanced machines and tools. There are a few methods to optimize the machining process, such as minimizing unit production time or cost or maximizing profit. This research focused on maximizing the profit of computer numerical control (CNC) milling operations by optimizing machining parameters. Cutting speeds and feed are considered as the main …


Ultrasonic Coda Wave Comparison For Quality Control Of Manufactured Parts: Proof Of Feasibility, Alexei Marin-Cortes Jul 2020

Ultrasonic Coda Wave Comparison For Quality Control Of Manufactured Parts: Proof Of Feasibility, Alexei Marin-Cortes

Civil and Environmental Engineering Master's Project Reports

Manufactured parts are a staple of modern urban life, visible in homes (e.g., kitchen appliances), offices (e.g., printers), the automobile and aerospace industries (e.g., body parts), and more. This M.S. project intended to determine whether ultrasonic testing could be used in a simple and rapid manner to perform quality control of manufactured parts. Ultrasonic testing is employed for this purpose using two surface-coupled transducers, one being a transmitter and the other one a receiver. An ultrasonic pulse, which is generated by the transmitting transducer, propagates through the part, collecting information about material and geometry, as well as potential unwanted features. …


Online Survey Of Driver Comprehension Of The Flashing Yellow Arrow For Right-Turn Signal Indications, Sirisha Kothuri, Christopher Monsere, Hisham Jashami, David Hurwitz Jul 2020

Online Survey Of Driver Comprehension Of The Flashing Yellow Arrow For Right-Turn Signal Indications, Sirisha Kothuri, Christopher Monsere, Hisham Jashami, David Hurwitz

Civil and Environmental Engineering Faculty Publications and Presentations

This paper presents the results of an online survey of licensed driver comprehension of the right-turn signal displays with a focus on the flashing yellow arrow (FYA) and also including the circular green and red and red arrow. Recruitment postcards were mailed to a random sample of 9,872 residents in Oregon. The online survey yielded 399 responses. The open-ended responses were coded for comprehension and analyzed. The results suggest that FYA for right turns is well understood by Oregon drivers despite its current novelty (only two locations at the time of the research). Importantly, survey respondents were more likely to …


Fabrication And Characterization Of Flexible Three-Phase Zno-Graphene-Epoxy Electro-Active Thin-Film Nanocomposites: Towards Applications In Wearable Biomedical Devices, Mandeep Singh, Sanjeev Kumar, Shervin Zoghi, Debaki Sarcar, Saquib Ahmed, Shaestagir Chowdhury, Sankha Banerjee Jul 2020

Fabrication And Characterization Of Flexible Three-Phase Zno-Graphene-Epoxy Electro-Active Thin-Film Nanocomposites: Towards Applications In Wearable Biomedical Devices, Mandeep Singh, Sanjeev Kumar, Shervin Zoghi, Debaki Sarcar, Saquib Ahmed, Shaestagir Chowdhury, Sankha Banerjee

Mechanical and Materials Engineering Faculty Publications and Presentations

Perovskite oxides have been used as sensors, actuators, transducers, for sound generation and detection, and also in optical instruments and microscopes. Perovskite halides are currently considered as optoelectronic devices such as solar cells, photodetectors, and radiation detection, but there are major issues with stability, interfacial recombination, and electron/hole mobility. The following work looks into the fabrication of non-toxic ZnO-based lead-free alternatives to perovskite oxides for use as secondary sensors or electron transport layers along with perovskite halides for application in stacked biomedical wearable devices. Three-phase, lead-free, Zinc Oxide-Graphene-Epoxy electroactive nanocomposite thin films were fabricated. The volume fraction of the Graphene …


Ce-Qual-W2 Hydrodynamic And Water Quality Model Of The Cedar River Municipal Watershed, Amory Spencer Cervarich Jul 2020

Ce-Qual-W2 Hydrodynamic And Water Quality Model Of The Cedar River Municipal Watershed, Amory Spencer Cervarich

Dissertations and Theses

The laterally averaged, two-dimensional model CE-QUAL-W2 was used to develop a water quality model of the Cedar River Municipal Watershed as a reservoir management and climate change scenario tool. The 90,638-acre watershed, located 56 kilometers southeast of Seattle, WA, provides drinking water to over 1.4 million people. The watershed relies on two waterbodies for storage, Chester Morse Lake and the Masonry Pool. The Masonry Dam is the main storage structure in the watershed. The Cedar River flows downstream from the Masonry Dam for 57 kilometers to Lake Washington. The reservoir model simulated Chester Morse Lake and the Masonry Pool. The …


Dynamic Response Of Highway Bridge Superstructures Subjected To Wave Action: Experimental Analysis And Numerical Modeling, Alaa Waleed Hameed Jun 2020

Dynamic Response Of Highway Bridge Superstructures Subjected To Wave Action: Experimental Analysis And Numerical Modeling, Alaa Waleed Hameed

Dissertations and Theses

Bridges are critical lifeline components of the infrastructure network, enabling economies to function under normal conditions and disaster response and recovery missions to take place after extreme events. Therefore, ensuring satisfactory performance increases community resilience and minimizes both human and economic losses. Coastal bridges, which are the focus of this PhD dissertation, are vulnerable to coastal storms. High failure rates of these bridges during two major hurricane events in the mid-2000s have spurred research activities to better understand the wave-induced forces of coastal bridges.

This PhD research represents a continuation effort to build, implement, and introduce new fundamental concepts and …


An Assessment Of The Decision-Making Units' Efficiency In Service Systems, Maoloud Yakhlif Dabab Jun 2020

An Assessment Of The Decision-Making Units' Efficiency In Service Systems, Maoloud Yakhlif Dabab

Dissertations and Theses

Most tools and models of performance and quality of service management are generic and do not solve complex technical systems. The critical components of the system need such tools to assess their efficiency to make a better decision about them. One of the primary objectives in the service systems is to improve the ability of efficiency, effectiveness, and sustainability of critical assets. One of the challenges with improving critical assets is the amount of major capital spending needed to upgrade a technology infrastructure with a high obsolescence rate. This along with usage and reliability issues, makes evaluating mobile cells to …


Design Of A 7-Mhz Portable Direct Conversion Transceiver With Digitally Controlled Keying, Abram Morphew Jun 2020

Design Of A 7-Mhz Portable Direct Conversion Transceiver With Digitally Controlled Keying, Abram Morphew

Dissertations and Theses

This thesis outlines the design of a portable direct conversion transceiver system for the 7-MHz (or 40m) band. This band is popular due to its propagation characteristics which allow for world-wide communication with very low power. The transceiver utilizes a crystal-stabilized local oscillator optimized for frequency agility, low power consumption, and an optimal drive level of +7 dBm. A low power 8-bit microcontroller acts as an interface for either a straight key providing manual Morse code operation or digital logic control from a personal computer. It also acts as a side tone oscillator providing audio feedback to the operator during …


Designing Gates And Architectures For Superconducting Quantum Systems, Sahar Daraeizadeh Jun 2020

Designing Gates And Architectures For Superconducting Quantum Systems, Sahar Daraeizadeh

Dissertations and Theses

Large-scale quantum computers can solve certain problems that are not tractable by currently available classical computational resources. The building blocks of quantum computers are qubits. Among many different physical realizations for qubits, superconducting qubits are one of the promising candidates to realize gate model quantum computers. In this dissertation, we present new multi-qubit gates for nearest-neighbor superconducting quantum systems. In the absence of a physical hardware, we simulate the dynamics of the quantum system and use the simulated environment as a framework for test, design, and optimization of quantum gates and architectures. We explore three different simulation-based gate design methodologies: …


Evidence From Urban Roads Without Bicycle Lanes On The Impact Of Bicycle Traffic On Passenger Car Travel Speeds, Jaclyn S. Schaefer, Miguel A. Figliozzi, Avinash Unnikrishnan Jun 2020

Evidence From Urban Roads Without Bicycle Lanes On The Impact Of Bicycle Traffic On Passenger Car Travel Speeds, Jaclyn S. Schaefer, Miguel A. Figliozzi, Avinash Unnikrishnan

Civil and Environmental Engineering Faculty Publications and Presentations

A concern raised by some motorists in relation to the presence of bicycles on urban roads without bicycle lanes, discussed in part of the traffic literature, is that cyclists will slow down motorized vehicles and therefore create congestion. This research answers this question: do bicycles reduce passenger car travel speeds on urban roads without bicycle lanes? To answer this question, a detailed comparative analysis of the travel speeds of passenger car (class two vehicles) on lower volume urban roads without bicycle lanes is presented. Speed distributions, the mean, and the 50th and 85th percentile speeds for two scenarios were examined: …


User-Rated Comfort And Preference Of Separated Bike Lane Intersection Designs, Christopher Monsere, Nathan Mcneil, Rebecca Sanders Jun 2020

User-Rated Comfort And Preference Of Separated Bike Lane Intersection Designs, Christopher Monsere, Nathan Mcneil, Rebecca Sanders

Civil and Environmental Engineering Faculty Publications and Presentations

Improved bicycle infrastructure has become increasingly common in the United States as cities seek to attract new riders, including the demographic who do not feel comfortable riding with motor vehicle traffic. A key tool in designing low-stress networks is the use of separated or protected bicycle lanes, and intersections are the critical links. This paper presents an analysis of the perceived level of comfort of current and potential bicyclists from 277 survey respondents who rated 26 first-person video clips of a bicyclist riding through mixing zones, lateral shifts, bend-in, bend-out, and protected intersection designs. A total of 7,166 ratings were …


Work-In-Progress: Implementing Sophomore Cornerstone Courses In Electrical And Computer Engineering, Branimir Pejcinovic, Melinda Holtzman, Phillip Wong Jun 2020

Work-In-Progress: Implementing Sophomore Cornerstone Courses In Electrical And Computer Engineering, Branimir Pejcinovic, Melinda Holtzman, Phillip Wong

Electrical and Computer Engineering Faculty Publications and Presentations

Many engineering programs have significant project-based courses in the freshman and senior years. The project component in our freshman year-long sequence evolves from minimally structured projects, like designing and building Rube-Goldberg contraptions, to more complex microcontroller-based projects where formal tools for teamwork and project management are introduced. However, we do not yet enforce strict adherence to procedures and processes in the freshman year. This is unlike the senior capstone, where the expectation is that students will not only be familiar with these methods but will use them effectively throughout their projects. This presents an obvious problem: what happens in the …


Dim: Adaptively Combining User Interests Mined At Different Stages Based On Deformable Interest Model, Xiaoru Wang, Yueli Li, Zhihong Yu, Fu Li, Heng Zhang, Yali Cai, Lixian Li May 2020

Dim: Adaptively Combining User Interests Mined At Different Stages Based On Deformable Interest Model, Xiaoru Wang, Yueli Li, Zhihong Yu, Fu Li, Heng Zhang, Yali Cai, Lixian Li

Electrical and Computer Engineering Faculty Publications and Presentations

User interest mining is widely used in the fields of personalized search and personalized recommendation. Traditional methods ignore the formation of user interest which is a process that evolves over time. This leads to the inability to accurately describe the distribution of user interest. In this paper, we propose the interest tracking model (ITM). To add the timing, ITM uses Dirichlet distribution and multinomial distribution to describe the evolutional process of interest topics and frequent patterns, which well adapts to the evolution of user interest hidden in short texts between different time slices. In addition, it is well known that …


Facilitating Mixed Self-Timed Circuits, Alexandra R. Hanson May 2020

Facilitating Mixed Self-Timed Circuits, Alexandra R. Hanson

University Honors Theses

Designers constrain the ordering of computation events in self-timed circuits to ensure the correct behavior of the circuits. Different circuit families utilize different constraints that, when families are combined, may be more difficult to guarantee in combination without inserting delay to postpone necessary events. By analyzing established constraints of different circuit families like Click and GasP, we are able to identify the small changes necessary to either 1) avoid constraints entirely; or 2) decrease the likelihood of necessary delay insertion. Because delay insertion can be tricky for novice designers and because the likelihood of its requirement increases when mixing different …


Optimized Xanthene-Based Probes For Pancreatic Cancer Imaging, Ian Ruramai Munhenzva May 2020

Optimized Xanthene-Based Probes For Pancreatic Cancer Imaging, Ian Ruramai Munhenzva

Dissertations and Theses

Pancreatic Ductal Adenocarcinoma (PDAC) is one of the deadliest human malignancies with an extremely poor 5-year survival rate of below 5%. Surgical resection is the most effective treatment of choice because chemotherapy and radiation therapy do not improve life expectancy. Residual tumor after PDAC surgery is common due to a lack of PDAC targeted intraoperative contrast agents to confirm clear margins.

Fluorescence imaging has the potential to improve surgery outcome and PDAC patients' survival rate via the use of highly PDAC-specific molecular probes to facilitate tumor identification. This thesis describes the application of a focused library of benzoxanthene fluorophores for …


Chehalis River And Tributary Water Quality And Hydrodynamic Modeling: Model Setup, Calibration Analysis For 2013-2015, Tel Jensen Apr 2020

Chehalis River And Tributary Water Quality And Hydrodynamic Modeling: Model Setup, Calibration Analysis For 2013-2015, Tel Jensen

Dissertations and Theses

The Chehalis River is located in southwest Washington State. Its headwaters are in the Willapa Hills, and it drains parts of the Doty Hills, the western foothills of the Cascade Mountains, and the southern Olympic Mountains. The Chehalis River is over 125 miles long and its basin is over 2000 square miles spanning parts of seven counties and diverse land uses.

CE-QUAL-W2 is a widely used two-dimensional (vertical and longitudinal) hydrodynamic and water quality model developed by the US Army Corp of Engineers and the Water Quality Research Group at Portland State University. Version 4.2 includes the ability to run …


Spectrum Modeling Of Out-Of-Band Intermodulation For Dual-Band Rf Amplifiers In Ofdm Modulation, Xianzhen Yang, Siyuan Yan, Xiao Li, Qiang Wu, Fu Li Apr 2020

Spectrum Modeling Of Out-Of-Band Intermodulation For Dual-Band Rf Amplifiers In Ofdm Modulation, Xianzhen Yang, Siyuan Yan, Xiao Li, Qiang Wu, Fu Li

Electrical and Computer Engineering Faculty Publications and Presentations

Dual-band RF amplifiers play increasingly important roles in next-generation mobile communication systems including 5G, and the out-of-band intermodulation products are often not negligible since they generate interference to adjacent channels. In this article, following our previous modeling of cross-modulation for amplified dual-band signals, an analytical expression of out-of-band intermodulation for dual-band orthogonal frequency-division multiplexing signals is derived using the third-order intercept points IP3. The experimental measurement results validate the proposed analytical expression.


A Numerical Investigation Of Microgravity Evaporation, Daniel Peter Ringle Apr 2020

A Numerical Investigation Of Microgravity Evaporation, Daniel Peter Ringle

Dissertations and Theses

Evaporation is important to myriad engineering processes such as cooling, distillation, thin film deposition, and others. In fact, NASA has renewed interest in using cabin air pressure evaporation as a means to recycle waste water in space. As one example, NASA recently conducted experiments aboard the International Space Station (ISS) to measure evaporation rates in microgravity and to determine the impacts of porous structure on the process. It has long been assumed that differences in evaporation rates between 1-g0 and microgravity are small. However, discrepancies by as much as 40% have been observed in practice. The assumption now …


Aggregated Water Heater System (Awhs) Optimization For Ancillary Services, Manasseh Obi Apr 2020

Aggregated Water Heater System (Awhs) Optimization For Ancillary Services, Manasseh Obi

Dissertations and Theses

In this dissertation, I present a two-stage optimization routine that schedules an Aggregated Water Heater System (AWHS) to concurrently provide three utility ancillary services, namely, frequency regulation, frequency response, and peak demand mitigation.

Water heaters can be controlled to manage their energy take, the amount of energy a water heater can absorb upon command. The AWHS is a model aggregation of thousands of water heaters, the energy take and power characteristics of which are based on U.S Census household data and usage behavior patterns. The aggregate energy take available in the AWHS may be dispatched en masse for participation in …


Enhanced Carrier Transport By Transition Metal Doping In Ws2 Field Effect Transistors, Maomao Liu, Sichen Wei, Simran Shahi, Hemendra Nath Jaiswal, Paolo Paletti, Sara Fathipour, Maja Remskar, Jun Jiao, Wansik Hwang, Fei Yao, Huamin Li Apr 2020

Enhanced Carrier Transport By Transition Metal Doping In Ws2 Field Effect Transistors, Maomao Liu, Sichen Wei, Simran Shahi, Hemendra Nath Jaiswal, Paolo Paletti, Sara Fathipour, Maja Remskar, Jun Jiao, Wansik Hwang, Fei Yao, Huamin Li

Physics Faculty Publications and Presentations

High contact resistance is one of the primary concerns for electronic device applications of two-dimensional (2D) layered semiconductors. Here, we explore the enhanced carrier transport through metal–semiconductor interfaces in WS2 field effect transistors (FETs) by introducing a typical transition metal, Cu, with two different doping strategies: (i) a “generalized” Cu doping by using randomly distributed Cu atoms along the channel and (ii) a “localized” Cu doping by adapting an ultrathin Cu layer at the metal–semiconductor interface. Compared to the pristine WS2 FETs, both the generalized Cu atomic dopant and localized Cu contact decoration can provide a Schottky-to-Ohmic contact …


Parametric Investigation Of Effect Of Abnormal Process Conditions On Self-Piercing Riveting, Taek-Eon Jeong, Dong-Hyuck Kam, Cheolhee Kim Apr 2020

Parametric Investigation Of Effect Of Abnormal Process Conditions On Self-Piercing Riveting, Taek-Eon Jeong, Dong-Hyuck Kam, Cheolhee Kim

Mechanical and Materials Engineering Faculty Publications and Presentations

Self-piercing riveting (SPR) is one of the mechanical joining processes, and its application to Al/Fe dissimilar materials combination, which is hard to weld, is expanding in the automotive industry. The main process parameters in SPR are types of rivet and die, setting force, and rivet setting speed. Previously, the relationship between the main process parameters and output parameters such as cross-sectional characteristics and joint strength has been studied to optimize the SPR process. In practical applications, there are unexpected and abnormal process conditions such as poor fit-up, angular misalignment, edge offset distance, and inaccurate setting and pre-clamping forces, and their …


Scanning Electron Microscopy (Sem) Investigation Of Morphology Changes In The Reduction Of Silica Nanoparticles To Elemental Silicon, Allison M. Cairns Apr 2020

Scanning Electron Microscopy (Sem) Investigation Of Morphology Changes In The Reduction Of Silica Nanoparticles To Elemental Silicon, Allison M. Cairns

University Honors Theses

The application of silicon nanoparticles varies from energy storage materials, to drug-delivery, and molecular recognition. Various chemical and physical properties of the Si nanoparticles arise from their morphology. This paper aims to reveal the morphology of Si nanoparticles following magnesiothermic reduction of silica (SiO2) nanoparticles. Two sets of SiO2 nanoparticles were used, commercially available NanoXact nanoparticles and laboratory-synthesized Stöber nanoparticles. A Zeiss Sigma VP FEG SEM was used to examine the morphology. Following the magnesiothermic reduction, the nanoparticles were etched with HF. Ten sets of images were taken of both Stöber and NanoXact nanoparticles: 1,2: the SiO …