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Graduate Theses, Dissertations, and Problem Reports

Theses/Dissertations

2023

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Full-Text Articles in Engineering

Evaluations Of Frp Composite Coupons Under Impact And Puncture, Lekhnath Bhandari Jan 2023

Evaluations Of Frp Composite Coupons Under Impact And Puncture, Lekhnath Bhandari

Graduate Theses, Dissertations, and Problem Reports

Evaluations of FRP Composite Coupons Under Impact and Puncture

Lekhnath Bhandari

Railroad tank cars are the main mode of transportation for carrying flammable liquids and other hazardous materials, in any mode of ground transportation system. These tank cars, if punctured during derailments may explode releasing large amounts of hazardous materials and posing serious threats to human life and leading to economic losses. To minimize such catastrophes, in 2015, United States Department of Transportation (USDOT) proposed to improve the thermal and puncture performances of these tank cars and introduced two new design specifications: DOT-117 and DOT-117R. Tank cars with 9/16 inches …


Weigh-In-Motion Data-Driven Pavement Performance Prediction Models, Mohhammad Afsar Sujon Jan 2023

Weigh-In-Motion Data-Driven Pavement Performance Prediction Models, Mohhammad Afsar Sujon

Graduate Theses, Dissertations, and Problem Reports

The effective functioning of pavements as a critical component of the transportation system necessitates the implementation of ongoing maintenance programs to safeguard this significant and valuable infrastructure and guarantee its optimal performance. The maintenance, rehabilitation, and reconstruction (MRR) program of the pavement structure is dependent on a multidimensional decision-making process, which considers the existing pavement structural condition and the anticipated future performance. Pavement Performance Prediction Models (PPPMs) have become indispensable tools for the efficient implementation of the MRR program and the minimization of associated costs by providing precise predictions of distress and roughness based on inventory and monitoring data concerning …


Microwave-Assisted Ammonia Synthesis Over Cs-Ru/Ceo2 Catalyst, Alazar Kesete Araia Jan 2023

Microwave-Assisted Ammonia Synthesis Over Cs-Ru/Ceo2 Catalyst, Alazar Kesete Araia

Graduate Theses, Dissertations, and Problem Reports

Ammonia synthesis is one of the greatest innovations of the 20th century with extensive applications from fertilizers to intermediates for nitrogen-containing chemicals and pharmaceuticals. Annually, more than 242 million tons of ammonia is produced globally, supporting approximately 27% of the world’s population. One of the fast-growing applications for ammonia is as H2 energy carrier due to its high energy storage capacity, considered to be a decarbonized energy source. The low volumetric energy density and incompressibility makes Hydrogen a non-preferable energy carrier; an alternative carrier becomes a requirement. Ammonia possesses unique property as an energy-dense carrier to store and …


A Computer Vision-Based Method For Tack Coat Coverage Inspection Using Drone-Collected Images, Aida Da Silva Jan 2023

A Computer Vision-Based Method For Tack Coat Coverage Inspection Using Drone-Collected Images, Aida Da Silva

Graduate Theses, Dissertations, and Problem Reports

Tack coat is a thin asphalt applied between the existing surface and asphalt overlay during road rehabilitation. The uniformity of tack coat coverage plays a vital role in providing adhesive bonding between the two layers in the pavement structures. To ensure tack coat uniformity, the current practice primarily relies on manual inspection during construction by field experts. This process is time-consuming and tedious, and the results can be subjective and error-prone. Drones have emerged as a non-destructive sensing technology in the construction industry for many inspection practices. Unlike other non-destructive inspection technologies, drones offer benefits ranging from accelerating data collection …


Optimizing Sample Collection And Data Interpretation For Effective Wastewater-Based Epidemiology In Combined Sewer Systems, Christopher Allen Anderson Jan 2023

Optimizing Sample Collection And Data Interpretation For Effective Wastewater-Based Epidemiology In Combined Sewer Systems, Christopher Allen Anderson

Graduate Theses, Dissertations, and Problem Reports

COVID-19 has spurred growth in the science surrounding wastewater-based epidemiology (WBE) pertaining to the detection of severe acute respiratory virus 2 (SARS-CoV-2) in waste streams as an early warning signal for public health. However, the highly variable wastewater environment has made it difficult to standardize an approach for sampling and analysis, especially in locations using combined sewer infrastructure. This study addresses knowledge gaps of WBE via three specific aims: (1) to compare diurnal fluctuations of SARS-CoV-2 and the human fecal indicator, pepper mild mottle virus (PMMoV) in wastewater treatment plant (WWTP) influent samples collected during dry versus wet weather conditions; …


Accelerating Manufacturing Decisions Using Bayesian Optimization: An Optimization And Prediction Perspective, Taofeeq Olajire Jan 2023

Accelerating Manufacturing Decisions Using Bayesian Optimization: An Optimization And Prediction Perspective, Taofeeq Olajire

Graduate Theses, Dissertations, and Problem Reports

Manufacturing is a promising technique for producing complex and custom-made parts with a high degree of precision. It can also provide us with desired materials and products with specified properties. To achieve that, it is crucial to find out the optimum point of process parameters that have a significant impact on the properties and quality of the final product. Unfortunately, optimizing these parameters can be challenging due to the complex and nonlinear nature of the underlying process, which becomes more complicated when there are conflicting objectives, sometimes with multiple goals. Furthermore, experiments are usually costly, time-consuming, and require expensive materials, …


Ai-Driven Security Constrained Unit Commitment Using Predictive Modeling And Eigen Decomposition, Talha Iqbal Jan 2023

Ai-Driven Security Constrained Unit Commitment Using Predictive Modeling And Eigen Decomposition, Talha Iqbal

Graduate Theses, Dissertations, and Problem Reports

Security Constrained Unit Commitment (SC-UC) is a complex large scale mix integer constrained optimization problem solved by Independent System Operators (ISOs) in the daily planning of the electricity markets. After receiving offers and bids, ISOs have only few hours to clear the day-ahead electricity market. It requires a lot of computational effort and a reasonable time to solve a large-scale SC-UC problem. However, exploiting the fact that a UC problem is solved several times a day with only minor changes in the system data, the computational effort can be reduced by learning from the historical data and identifying the patterns …


Biologically – Plausible Load Feedback From Dynamically Scaled Robotic Model Insect Legs, William Zyhowski Jan 2023

Biologically – Plausible Load Feedback From Dynamically Scaled Robotic Model Insect Legs, William Zyhowski

Graduate Theses, Dissertations, and Problem Reports

Researchers have been studying the mechanisms underlying animal motor control for many years using computational models and biomimetic robots. Since testing some theories in animals can be challenging, this approach can enable unique contributions to the field. An example of a system that benefits from this modeling and robotics approach is the campaniform sensillum (CS), a kind of sensory organ used to detect the loads exerted on an insect's legs. The CS on the leg are found in groups on high-stress areas of the exoskeleton and have a major influence on the adaptation of walking behavior. The challenge for studying …


Augmented Reality And Mobile Systems For Heavy Equipment Operators In Surface Mining, Juan David Valencia Quiceno Jan 2023

Augmented Reality And Mobile Systems For Heavy Equipment Operators In Surface Mining, Juan David Valencia Quiceno

Graduate Theses, Dissertations, and Problem Reports

U.S. federal laws mandate that mining companies ensure a safe workplace, implement approved training programs, and promptly report work-related injuries. The mining industry's commitment to innovation reflects a history of adopting advancements to enhance environmental sustainability, workplace safety, and overall productivity, while simultaneously reducing operational costs. This thesis proposes the integration of Augmented Reality (AR) technology and digital applications to enhance the surface mining industry, presenting two innovative solutions: an AR Training System and an Operational Digital System. These business solutions have been developed and applied at a surface mine in the southwest of the US, having the potential to …


Development Of A Hydrometallurgical Process For The Extraction Of Cobalt, Manganese, And Nickel From Acid Mine Drainage Treatment Byproduct, Alejandro Agudelo Mira Jan 2023

Development Of A Hydrometallurgical Process For The Extraction Of Cobalt, Manganese, And Nickel From Acid Mine Drainage Treatment Byproduct, Alejandro Agudelo Mira

Graduate Theses, Dissertations, and Problem Reports

Critical minerals (CMs) are defined as crucial elements for the country's economy due to the development of new cutting-edge applications and the risk of an eventual disruption in their supply chain. The unique chemical and physical properties of the CMs have made these elements decisive in the growth of industries such as telecommunications, army, medicine, Aerospace, etc. In 2022, the US Geological Survey established a list of 50 CMs, including manganese, cobalt, nickel, aluminum, magnesium, and others. Of the total of CMs, 26 are 100% imported from outside the United States (Venditti, 2022).

Driven by the ever-increasing demand for critical …


Integrated Immunity-Based Methodology For Uav Monitoring And Control, Ryan G. Mclaughlin Jan 2023

Integrated Immunity-Based Methodology For Uav Monitoring And Control, Ryan G. Mclaughlin

Graduate Theses, Dissertations, and Problem Reports

A general integrated and comprehensive health management framework based on the artificial immune system (AIS) paradigm is formulated and an automated system is developed and tested through simulation for the detection, identification, evaluation, and accommodation (DIEA) of abnormal conditions (ACs) on an unmanned aerial vehicle (UAV). The proposed methodology involves the establishment of a body of data to represent the function of the vehicle under nominal conditions, called the self, and differentiating this operation from that of the vehicle under an abnormal condition, referred to as the non-self. Data collected from simulations of the selected UAV autonomously flying a set …


Exploiting The Advantages And Overcoming The Challenges Of The Cable In A Tethered Drone System, Rogerio Rodrigues Lima Jan 2023

Exploiting The Advantages And Overcoming The Challenges Of The Cable In A Tethered Drone System, Rogerio Rodrigues Lima

Graduate Theses, Dissertations, and Problem Reports

This dissertation proposes solutions for motion planning, localization, and landing of tethered drones using only tether variables. A tether-based multi-model localization framework for tethered drones is proposed. This framework comprises three independent localization strategies based on a different model. The first strategy uses simple trigonometric relations assuming that the tether is taut; the second method relies on a set of catenary equations for the slack tether case; the third estimator is a neural network-based predictor that can cover different tether shapes. Multi-layer perceptron networks previously trained with a dataset comprised of the tether variables (i.e., length, tether angles on the …


Implementing Test Automation With Selenium Webdriver, Ramana Inturi Jan 2023

Implementing Test Automation With Selenium Webdriver, Ramana Inturi

Graduate Theses, Dissertations, and Problem Reports

Many software programs, such as applications for designing, modeling, simulating, and analyzing systems, are now commonly available as web-based applications. The testing of such sophisticated web applications is highly challenging and can be extremely tedious and error-prone if done manually. Recently automation tools have become increasingly used for testing web-based applications, as they minimize human involvement and repetitive work.

For this problem report project, we have built and implemented an automation testing framework for web applications. The project specifically uses a tool called Selenium WebDriver, which has been used to develop the testing framework. By using this framework, testers may …


Robust State Estimation Methods For Robotics Applications, Shounak Das Jan 2023

Robust State Estimation Methods For Robotics Applications, Shounak Das

Graduate Theses, Dissertations, and Problem Reports

State estimation is an integral component of any autonomous robotic system. Finding the correct position, velocity, and orientation of an agent in its environment enables it to do other tasks like mapping and interacting with the environment, and collaborating with other agents. State estimation is achieved by using data obtained from multiple sensors and fusing them in a probabilistic framework. These include inertial data from Inertial Measurement Unit (IMU), images from camera, range data from lidars, and positioning data from Global Navigation Satellite Systems (GNSS) receivers. The main challenge faced in sensor-based state estimation is the presence of noisy, erroneous, …


System Analysis Of An Internal Combustion Engine (Ice) – Solid Oxide Fuel Cell (Sofc) Hybrid Cycle, Jose Javier Colon Rodriguez Jan 2023

System Analysis Of An Internal Combustion Engine (Ice) – Solid Oxide Fuel Cell (Sofc) Hybrid Cycle, Jose Javier Colon Rodriguez

Graduate Theses, Dissertations, and Problem Reports

Due to the intermittent nature of renewable energy and the rigid operation of existing coal plants, the need for flexible power generation technology is eminent. Hybrid energy systems have shown potential for flexible, grid following dynamics while maintaining higher efficiencies. The work below focuses on the performance analysis of a proposed 100 kW pressurized Internal Combustion Engine (ICE) and Solid Oxide Fuel Cell (SOFC) hybrid system. The un-utilized fuel from the SOFC stack provided the chemical energy to operate the engine. A turbocharger was used to deliver the necessary air flow for both the stack and engine. An external reformer …


Optimal Deployment Of Air Vehicle As Communication Relay For Multiple Ground Vehicles, Juan David Pabon Arias Jan 2023

Optimal Deployment Of Air Vehicle As Communication Relay For Multiple Ground Vehicles, Juan David Pabon Arias

Graduate Theses, Dissertations, and Problem Reports

Heterogeneous teams of both air and ground mobile vehicles can combine the advantages of mobility, sensing capability, and operation time when performing complex tasks. However, when ground vehicles operate in cluttered environments with randomized obstacles, they may experience line of sight (LoS) obstructions and loss of communication due to those obstacles. To mitigate this issue, an airborne relay can be positioned in the vicinity of the ground vehicles to aid communication by establishing two-hop communication links between the vehicles.

This thesis develops an analytical framework to calculate the probability of spanning a two-hop communication between a pair of ground vehicles …


Analysis Of The Root Causes Of Fatal Injuries In The United States Surface Mines Between 2008 And 2021., Maria Fernanda Quintero Jan 2023

Analysis Of The Root Causes Of Fatal Injuries In The United States Surface Mines Between 2008 And 2021., Maria Fernanda Quintero

Graduate Theses, Dissertations, and Problem Reports

Mining has long been recognized as a hazardous industry worldwide. An annual average rate of 10.3 fatal injuries per 100,000 workers was recorded in the United States between 2008 and 2021 (MSHA, 2022). This rate can be compared with the average of the industries with the highest average rates of fatal injuries—agriculture, forestry, fishing, and hunting; transportation and warehousing; and construction—which had average rates of 23.5, 13.1, and 9.9 fatal injuries per 100,000 workers, respectively, during the same period in the Unites States (U.S. Bureau of Labor Statistics, 2023).

The scope of this research is related to the fatal injuries …


Identification Of Rockmass Deformation And Lithological Changes In Underground Mines By Using Slam-Based Lidar Technology, Francisco Eduardo Gil Hurtado Jan 2023

Identification Of Rockmass Deformation And Lithological Changes In Underground Mines By Using Slam-Based Lidar Technology, Francisco Eduardo Gil Hurtado

Graduate Theses, Dissertations, and Problem Reports

In mining, hazards causing rib and roof fall accidents generally develop with time. The development of a hazard depends on factors like geology, excavation geometry, overburden stress, and mining-induced stresses. Hazard mapping in an underground mine is essential for roof and rib stability assessment. However, often it is neither practical nor economical to inspect and map vast areas of mine workings with limited personnel. New technologies, recently, have been adopted in the mining industry that can solve this problem. Advances in LiDAR technology and simultaneous localization and mapping (SLAM) algorithms have led to the development of portable and mobile laser …


Exploring The Usage Of Acid Mine Drainage Sludge As A Soil Amendment For Reclaimed Mine Lands, Brady Watters Jan 2023

Exploring The Usage Of Acid Mine Drainage Sludge As A Soil Amendment For Reclaimed Mine Lands, Brady Watters

Graduate Theses, Dissertations, and Problem Reports

Acid mine drainage (AMD) is a form of water pollution generated when water and oxygen come into contact with sulfide minerals, forming metal ions, sulfuric acid, and sulphates in solution. AMD is characterized by its toxic metals content and low pH, both of which are an environmental concern. The treatment of AMD separates the contaminants into a high-water content sludge. This sludge is a pure waste product under current evaluation for alternative uses as well as improvements to storage and treatment processes. This thesis focused on analyzing the potential for AMD sludge to be used in recently reclaimed lands as …


Development Of Machine Learning Based Approach To Predict Fuel Consumption And Maintenance Cost Of Heavy-Duty Vehicles Using Diesel And Alternative Fuels, Sasanka Katreddi Jan 2023

Development Of Machine Learning Based Approach To Predict Fuel Consumption And Maintenance Cost Of Heavy-Duty Vehicles Using Diesel And Alternative Fuels, Sasanka Katreddi

Graduate Theses, Dissertations, and Problem Reports

One of the major contributors of human-made greenhouse gases (GHG) namely carbon dioxide (CO2), methane (CH4), and nitrous oxide (NOX) in the transportation sector and heavy-duty vehicles (HDV) contributing to about 27% of the overall fraction. In addition to the rapid increase in global temperature, airborne pollutants from diesel vehicles also present a risk to human health. Even a small improvement that could potentially drive energy savings to the century-old mature diesel technology could yield a significant impact on minimizing greenhouse gas emissions. With the increasing focus on reducing emissions and operating costs, there is a need for efficient and …


Selective Recovery Of Rare Earth Elements From Acid Mine Drainage Treatment Byproduct, Zeynep Cicek Jan 2023

Selective Recovery Of Rare Earth Elements From Acid Mine Drainage Treatment Byproduct, Zeynep Cicek

Graduate Theses, Dissertations, and Problem Reports

Rare earth elements (REEs) are critical in emerging clean energy, advanced technologies, and military defense applications due to their unique physical, chemical, optical, and luminescent properties. Given the potential supply chain restrictions imposed by one country's dominance in the global REE market and the consistently growing demand for REEs, developing the US domestic REE supply chain is imperative. Thus, alternative sources are crucial to supply the demand and prevent interruption in manufacturing products that consume REEs. Concurrently, acid mine drainage (AMD) is a long-standing and widespread global challenge the mining industry encounters. AMD is generated in large volumes and continuously …


Structural Health Monitoring Using Machine Learning And Synthetic Data, Michail Tzimas Jan 2023

Structural Health Monitoring Using Machine Learning And Synthetic Data, Michail Tzimas

Graduate Theses, Dissertations, and Problem Reports

Structural health monitoring spans many decades of research across multiple engineering fields. However, typical monitoring processes for damage detection of complex structures usually prohibit real-time or fast detection of debilitating damage to the structure. One of the major issues of real-time detection of damage is the enormity of data that needs to be processed, which is worsened by the relative inability of fast relaying of data to structural engineers. With the rapid advancement of Machine Learning, both issues can be overcome, and detection of failure is achieved with non-invasive techniques. This dissertation explores the applicability of Machine Learning as a …


Modular Supply Network Optimization Of Renewable Ammonia And Methanol Co-Production, Benjamin Akoh Jan 2023

Modular Supply Network Optimization Of Renewable Ammonia And Methanol Co-Production, Benjamin Akoh

Graduate Theses, Dissertations, and Problem Reports

To reduce the use of fossil fuels and other carbonaceous fuels, renewable energy sources such as solar, wind, geothermal energy have been suggested to be promising alternative energy that guarantee sustainable and clean environment. However, the availability of renewable energy has been limited due to its dependence on weather and geographical location. This challenge is intended to be solved by the utilization of the renewable energy in the production of chemical energy carriers. Hydrogen has been proposed as a potential renewable energy carrier, however, its chemical instability and high liquefaction energy makes researchers seek for other alternative energy carriers. Ammonia …


Simulations Of Implementation Of Advanced Communication Technologies, Ivy Yousuf Moutushi Jan 2023

Simulations Of Implementation Of Advanced Communication Technologies, Ivy Yousuf Moutushi

Graduate Theses, Dissertations, and Problem Reports

Wireless communication systems have seen significant advancements with the introduction of 3G, 4G, and 5G mobile standards. Since the simulation of entire systems is complex and may not allow evaluation of the impact of individual techniques, this thesis presents techniques and results for simulating the performance of advanced signaling techniques used in 3G, 4G, and 5G systems, including Code division multiple access (CDMA), Multiple Input Multiple Output (MIMO) systems, and Low-Density Parity Check (LDPC) codes. One implementation issue that is explored is the use of quantized Analog to Digital Converter (ADC) outputs and their impact on system performance.

Code division …


Energy Digital Twins In Smart Manufacturing Systems, Anna Billey Jan 2023

Energy Digital Twins In Smart Manufacturing Systems, Anna Billey

Graduate Theses, Dissertations, and Problem Reports

In this thesis, an Energy Digital Twin for smart manufacturing systems was developed and evaluated. In particular, the study focused on bidirectional parameter communication between the physical and the virtual part with the aim of optimizing the energy used in the manufacturing process. Rising costs and the environmental impacts related to energy consumption have grown in importance worldwide. There are elevated concerns in sectors like manufacturing, leading to an urgent quest to reduce energy consumption. A recent advancement in Industry 4.0 technology, the Digital Twin, represents a promising smart technology and tool that researchers are investigating to help reduce energy …


Lithium-Ion Battery Safety Analysis With Physical Sub-Models, Samuel Abimbola Ogunfuye Jan 2023

Lithium-Ion Battery Safety Analysis With Physical Sub-Models, Samuel Abimbola Ogunfuye

Graduate Theses, Dissertations, and Problem Reports

Ever-increasing explosions occurring globally at a rapid rate and in diverse situations have re-established the fact that novel, faster, and more accurate approaches must be developed to analyze and possibly curb these explosions and avert their future occurrences. Experimental endeavors and computational fluid dynamics (CFD) simulations as compared to engineering models generally require enormous time, and resources, as well as a high-level of expertise and technicalities. This might, however, delay prompt analysis and the ability to draw conclusions, thereby causing setbacks in recommending safety measures for different situations and conditions. Therefore, robust models which are accurate and fast to give …


A Machine Learning Approach For Early Diagnosis Of Transthyretin Amyloid Cardiomyopathy Among Heart Failure Patients, Tanjim Ahmed Jan 2023

A Machine Learning Approach For Early Diagnosis Of Transthyretin Amyloid Cardiomyopathy Among Heart Failure Patients, Tanjim Ahmed

Graduate Theses, Dissertations, and Problem Reports

Transthyretin Amyloid Cardiomyopathy (ATTR-CM) is a rare, progressive, and fatal disease. Prevalence of ATTR-CM ranges from 4 to 17 per 100000 cases where the mean survival time is less than 4 years. It has a history of being underdiagnosed and misdiagnosed. The diagnosis delay has a weighted mean of 6.1 years for wild-type ATTR-CM. Low awareness, the necessity of invasive procedures, and lack of treatment are the key reasons for delayed diagnosis. But, with the introduction of non-invasive tests like nuclear scintigraphy with 99mTC-PYP and the disease modifying drug Tafamidis, the diagnosis delay signifies a missed opportunity to increase …


State Estimation, Covariance Estimation, And Economic Optimization Of Semi-Batch Bioprocesses, Ronald Hunter Alexander Jan 2023

State Estimation, Covariance Estimation, And Economic Optimization Of Semi-Batch Bioprocesses, Ronald Hunter Alexander

Graduate Theses, Dissertations, and Problem Reports

One of the most critical aspects of any chemical process engineer is the ability to gather, analyze, and trust incoming process data as it is often required in control and process monitoring applications. In real processes, online data can be unreliable due to factors such as poor tuning, calibration drift, or mechanical drift. Outside of these sources of noise, it may not be economically viable to directly measure all process states of interest (e.g., component concentrations). While process models can help validate incoming process data, models are often subject to plant-model mismatches, unmodeled disturbances, or lack enough detail to track …


Development Of A Framework To Support Community-Scale Nutrient Recovery For Local Crop Fertilization And Production, Scott A. Lopez Jan 2023

Development Of A Framework To Support Community-Scale Nutrient Recovery For Local Crop Fertilization And Production, Scott A. Lopez

Graduate Theses, Dissertations, and Problem Reports

Nutrient and resource recovery (NRR) has become increasingly crucial as regions face deteriorating sanitation infrastructures, limited support, and growing environmental challenges. Implementing region-specific NRR technologies and systems could provide effective circular economy insights into addressing these challenges. Because of the multidisciplinary challenges associated with the design and implementation of NRR strategies, various government and local decision-makers need to collaborate effectively in the decision-making process. Structured decision-making (SDM) methodologies are practical when determining the most appropriate NRR strategy for nutrient-rich waste streams. However, applications of computational SDM limited because of the vast amounts of data that are needed to analyze the …


Synthesis Of Quasi-Freestanding Graphene Films Using Radical Species Formed In Cold Plasmas, Michael A. Mathews Jr. Jan 2023

Synthesis Of Quasi-Freestanding Graphene Films Using Radical Species Formed In Cold Plasmas, Michael A. Mathews Jr.

Graduate Theses, Dissertations, and Problem Reports

For over a decade, the Stinespring laboratory has investigated scalable, plasma assisted synthesis (PAS) methods for the growth of graphene films on silicon carbide (SiC). These typically utilized CF4-based inductively coupled plasma (ICP) with reactive ion etching (RIE) to selectively etch silicon from the SiC lattice. This yielded a halogenated carbon-rich surface layer which was then annealed to produce the graphene layers. The thickness of the films was controlled by the plasma parameters, and overall, the process was readily scalable to the diameter of the SiC wafer.

The PAS process reproducibly yielded two- to three-layer thick graphene films …