Digital Commons Network^™

Microstructured Microstructure: Effects Of Concentration Variations On Shock Initiation Of Hmx-Based Plastic Explosives, Dana D. Dlott, Lawrence Salvati, Siva Kumar Valluri

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We studied shock-compressed plastic-bonded explosives (PBX) consisting of HMX (cyclotetramethylene-tetranitramine) with PDMS (poly-dimethylsiloxane) binder, where we varied the HMX weight percent (wt%) up to a maximum of 60 wt%. In this lower-concentration regime, HMX particle clustering causes the PBX structure to consist of HMX clusters and PDMS islands. Structural analysis by optical microscopy allowed us to compute a radial correlation function that gives the mean distance from an average HMX particle to the nearest polymer island. Short-duration 20 GPa shocks (4 ns) created hot spots, and time-resolved thermal emission was used to obtain the growth rate of the subsequent deflagration. …

Accelerating Shock-Driven Reactions In Metal Nanocomposites, Siva Kumar Valluri, Edward L. Dreizin, Dana D. Dlott

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Metal powders are sought as energetic additives to conventional explosives. However, due to their sluggish reaction kinetics with external gaseous oxidizers, pure metals are replaced with metallic composites with intimately mixed condensed phase oxidizers prepared by arrested reactive milling (ARM). Such composites can be initiated by non-thermal, mechanical means; through shear mixing of fuel and oxidizer under a shock compressive load. Since the ARM preparatory technique allows for tuning multiple powder attributes such as fuel/oxidizer of interest, their degree of mixing, amount of oxidizer, particle porosity, among others, a parametric study is crucial in identifying suitable traits for fast reactions …

Hyperspectral Imaging For Temperature Measurements Of Hot Spots In Shocked Plastic-Bonded Explosives, Dhanalakshmi Sellan, Siva Kumar Valluri, Dana D. Dlott

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Hot spots are formed when energetic microstructures are shocked, and they play a critical role in shock sensitivity. It is important to know both the time-dependent size and temperature of the hot spots, in order to generate a kinetic model to describe reaction growth in plastic-bonded explosives (PBX). Here we use a recently developed technique where PBX is fabricated in the form of a thin wafer, embedded within a transparent polymer binder, and shocked with a laser-launched flyer plate that produces pressures of about 30 GPa range. In this method, every crystal of the cyclotetramethylene-tetranitramine (HMX)-based PBX can be observed …

Development Of A Stable And Buffered Reference Electrode For Binary Molten Chlorides Salts, Carlos Mejia, Nicholas Christensen, Ricardo Rodriguez Ceron, Devin Rappleye

Faculty Publications

The development of stable and buffered reference electrodes (REs) is crucial for molten salt electrochemistry, particularly in pyrochemical processing, such as electrorefining. These REs must maintain a stable potential to ensure precise control over electrorefining processes by preventing unwanted shifts in the potential that could lead to impurity deposition. This study evaluated metal chlorides and metal oxides as potential candidates for REs, with their stability assessed via electrochemical methods over extended durations. While metal chloride-based REs exhibited stable potential behavior over time, their response followed the Nernst equation, leading to potential shifts with varying concentrations of oxidized species. Metal oxide-based …

Mems 411: Diving Bubbler, Yasmin Ruff, Maya Ghatalia, Selva Moslehikhah

Mechanical Engineering Design Project Class

Design an affordable, portable, and effective surface-breaking system tailored for the WashU Diving team.

Mems 411: Gentle Washing Machine For Reclem Clothing, Sadie Karp, Anna Clyne, Gabby Kogler

Mechanical Engineering Design Project Class

For our senior design project we worked with Dr. Mary Ruppert-Stroescu, Associate Professor at the Sam Fox School, and her company RECLEM to create a sustainable method for washing her clothing creations. RECLEM re-purposes old clothing scraps for sustainable garment manufacturing. RECLEM is experiencing a problem of deformation of her clothing when the pieces are go through a washing machine cycle. After completing our customer interview, we realized the root cause of the problem was the aggressive environment created by the washing machine. To combat this, we created a new washing process that is both scalable and gentle. Our design …

Mems 411: Asme Ball Bearing Sorter, Gurks Bansal, Natalia Klim, Helen Ma

Mechanical Engineering Design Project Class

Design and create a device that sorts ball bearings of 3 different materials and 2 different sizes for the 2024-2025 ASME Student Design Competition.

Mems 411: Reclém Clothes Washer Group X, Andrew Johnson, Eleni Kambouris, Ana Morgan Canales, Sheridan Lee

Mechanical Engineering Design Project Class

The RECLÉM Clothes Washer Project addresses the challenge faced by Dr. Ruppert-Stroescu and RECLÉM in efficiently washing repurposed textiles without damaging or deforming the fabric. The goal is to design a sustainable machine that dissolves water-soluble synthetic sheets while conserving water and maintaining fabric integrity.

Mems 411: Pipe Climbing Robot, Trevor S. Gilkerson, Nick M. Gunter, Phillip H. Le, Andru N. Mangkusubroto

Mechanical Engineering Design Project Class

Decreasing chemical plant emissions allow systems to become safer, less polluting, and more profitable. Pipe leaks in chemical plants, or fugitive emissions, are a significant source of lost product and safety hazard for workers. Working with Amaren's Maryland Heights natural gas power plant, the team developed a robot that can traverse pipe systems with a final goal of detecting chemical leaks.

Mems 411: Ball Bearing Sorting Device, Claudia Markel, Max Cusick, Tomás Collado

Mechanical Engineering Design Project Class

Ball bearings are an integral part of many products, including cars, planes, and appliances. However, when bearings of multiple sizes and materials are mixed together, they can be difficult to separate quickly. Sorting the ball bearings becomes even more of a challenge for people who are not able to see the difference in color to discern the materials. To solve this problem, a ball bearing sorter, which can separate bearings of 1 2 in and 1 4 in for the materials of steel, brass, and plastic, was created. This project was based on the American Society of Mechanical Engineers 2024-2025 …

Mems 411: Water Surface Tension Breaker, David Arthur D'Alessandro Iii, Ben Davis Miller, Jared Ethan Appel, Parker Monnig

Mechanical Engineering Design Project Class

Design a device that sufficiently stirs up the pool's surface for WashU's Swim and Dive team.

Mems 411: Custom Surfacing Machine, Katherine Minielly, Gaelen Clayton, Estela Villacis

Mechanical Engineering Design Project Class

Our project is in partnership with DeepSight, a startup working to revolutionize medical imaging through proprietary ultrasound sensing technology. Our objective is to create a custom surfacing machine to finish a critical ultrasound component. DeepSight’s new ultrasound system includes an aluminum component that requires a high degree of perpendicularity and a sub-micron finish on one side. DeepSight provided us with an existing grinding machine to retrofit to surface the aluminum part. Our goals were a surface roughness ofmicron, a surface perpendicularity ofmicrons, and the ability to process 3 parts inpart’s surface and ensure even surface wear. The part spins on …

Unveiling The Shadows: The Influence Of Anonymity And Fake Accounts On Cyberbully Intention In Social Media, Muzdalini Malik, Hapini Awang, Nur Suhaili Mansor, Mohamad Fadli Zolkipli, Khuzairi Mohd Zaini, Abdulrazak F. Shahatha Al-Mashhadani

Iraqi Journal for Computer Science and Mathematics

Cyberbullying has arisen as a prevalent and worrying issue in the digital age, substantially influencing the well-being and mental health of social media users. Previous studies have identified several factors and theories of cyberbullying. Still more in-depth research is required to understand the key factors influencing cyberbullying intention in social media. This study aims to identify the factors influencing cyberbullying intention in social media and examine the moderating effect of fake accounts on cyberbullying intention. An extensive literature review has been conducted to examine the gaps in existing studies on cyberbullying intention. As a result, this study uses the Theory …

Complex Precipitation Behavior In A Co-Free High Entropy Alloy During Aging, Matthew Luebbe, Fan Zhang, Jonathan D. Poplawsky, Jiaqi Duan, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

High entropy alloys (HEAs) demonstrate high strength, thermal stability, and irradiation resistance, making them desirable for applications in nuclear reactors and other harsh environments. Many existing HEAs contain cobalt (Co), which makes them unsuitable for nuclear applications due to the long-term activation of Co. A previously studied Co-free alloy, (Fe_0.3Ni_0.3Mn_0.3Cr_0.1)₈₈Ti₄Al₈, exhibits high strength but compromised ductility due to its network of brittle precipitates upon aging. This work investigates the formation mechanism and evolution of the precipitates, including L1₂ (Ni₃Ti type, ordered face-centered cubic …

Winter Solstice Phenomenon At Newgrange: Research Report 2024, Frank Prendergast

Articles

This report, commissioned by the National Monuments Service presents a comprehensive analysis of the high-resolution photographic and video recordings of the solar illumination inside the burial chamber at Newgrange passage tomb, located within the UNESCO World Heritage Site of Brú na Bóinne – Archaeological Ensemble of the Bend of the Boyne.

Nasa Microgreen Cultivation In Space Utilizing Pegda Hydrogels, Thomas Alarcon Ali, Zohaib Gabriel Khan, Ariel Marroquin, Samuel Martinez, Fabiha Samiha, Emily Yong

Publications and Research

During long-term space expeditions, it is crucial that astronauts receive the nutrients they need to maintain their overall health. While the current space diet of palatable foods is commendable and constantly evolving, nutritional content and food quality degrades over long durations. Microgreens are excellent candidates for space cultivation because they are nutrient-dense, young plants that are are densely grown and harvested when leaves are just emerging. However, antigravity, microgreen fragility, degradation speed, contamination, and limited water resources are substantial barriers to doing so. This study aims to address these challenges by cultivating microgreens inside a hydrogel, a soilless medium, to …

Valve Train Design And Material Testing, Luis Luna

Publications and Research

In automotive engineering, CAD software like SolidWorks enables engineers to design and simulate mechanical components efficiently, reducing the need for extensive prototyping. This project examines the rocker arm's performance and durability within a valve train system. Components like pushrods, camshafts, and rocker arms control air intake and exhaust timing. Due to its high-impact motion and exposure to elevated temperatures, the rocker arm endures considerable wear. This study uses SolidWorks and Finite Element Analysis (FEA) to analyze the rocker arm's stress, deformation, and wear potential during camshaft movement. Material testing and motion analysis results provide insights into improving the durability of …

Sustainability Assessment Of Photovoltaic Cells In Cross-Functional Applications, Achyuth Ravilla

Dissertations and Theses

Achieving the G7 countries' net-zero emissions target by 2050 requires integrating photovoltaic (PV) systems into diverse cross-functional applications that support sustainable energy transitions across multiple sectors. This dissertation explores the economic and environmental sustainability of three such applications: agrivoltaics, lower-dimensional materials in perovskite solar cells, and PV-electrochemical water-splitting technologies for hydrogen production. Employing life cycle assessment (LCA) and techno-economic analysis (TEA), we address the knowledge gap in comprehensive evaluations of PV-integrated solutions.

The first chapter assesses agrivoltaic systems (AVS), which combine PV systems with agriculture to mitigate land-use conflicts while enhancing food and energy production. Findings indicate that AVS designs, …

Propagation Modeling Of Terahertz Reflections And Reflector Design For Mimo Channel, Thanh Ngoc Dan Le

Dissertations and Theses

Wireless communication has transformed connectivity, enabling seamless access across devices without physical constraints. Terahertz (THz) frequencies, ranging from 100 GHz to 10 THz, promise high-bandwidth channels crucial for applications like IoT and virtual reality. However, deploying THz communication faces challenges due to significant propagation limitations such as high attenuation and environmental absorption. The motivation behind this research is to develop a comprehensive understanding of THz propagation dynamics and utilize reflective surfaces to create multipath environments for an improvement in the capacity performance of MIMO channels.

This research investigates the potential of Multi-Input Multi-Output (MIMO) channels at THz frequencies to overcome …

Applying Positive Unlabeled Learning Techniques And Using The Kullback-Leibler Divergence To Improve Geothermal Surveying Assessments, Martín Thomas Rodriguez

Dissertations and Theses

As we face the current climate crisis, the discovery of geothermal energy resources has the potential to greatly reduce our dependence on fossil fuels worldwide. However, the development of any new energy infrastructure is expensive and depends on the willingness of energy agencies and developers to make initial investments based on calculated risk measures. One such measure, called geothermal favorability, is the likelihood that a site has conditions favorable for geothermal systems containing recoverable energy potential. Its prediction from existing geophysical datasets proves to be a nontrivial task. The prediction of geothermal favorability can be framed as a binary classification …

Understanding The Role Of The Heat Transfer Coefficient Between Tool/Workpiece Interface During Friction Stir Welding, Matthew Goodson

Theses and Dissertations

The heat transfer coefficient is a key parameter in modeling friction stir welding and has yet to be measured experimentally. The importance of this parameter was shown through validating friction stir models on both sides of the tool/workpiece interface. Both a transient plunge and a steady state model were validated by matching experimental temperatures. The steady state tool temperatures were matched (with in 2.5%), but the steady state workpiece temperatures were off by around 20%. The transient model of the FSW plunge showed the effect of varying the ℎ𝑊/𝑇 on workpiece temperatures and tool temperatures. Two methods were looked at …

Processing Cost Analysis For Great South Metals, Evan Briggs, Madisen Laskos, Jared Perrin

Senior Design Project For Engineers

Great south Metals (GSM), a steel processing company based in Acworth, GA, has partnered with the Kennesaw State University (KSU) Industrial and System Engineering (ISYE) department to optimize its costing model. Currently, GSM uses a flat pricing structure for GSM-owned materials and estimates costs for toll processing. However, this approach has led to inaccuracies in pricing and challenges in tracking profitability. GSM seeks to transition to a more systematic and data-driven costing model that will improve both internal and external quoting while ensuring competitiveness in the market.

To address these challenges, the project focused on developing separate costing matrices for …

Measuring Gait Of Total Knee Arthroplasty Patients Pre-Op And Post-Op Using A Smartphone, Celeste A. Thai

Master's Theses

Motion capture technology is a tool often used in orthopedic applications, including measuring gait dysfunctions. However, gait analysis research focused on total knee arthroplasty (TKA) patients is limited, especially using motion capture systems. This may be due to a multitude of factors, such as inaccessibility to gait labs to the general public, difficulty of travel post-surgery, and overall costs of care and maintenance of motion lab equipment. New emerging novel methods use wearable devices such as smartphones and inertial measurement devices (IMUs) to perform gait assessment and are becoming favorable due to their increasingly ubiquitous nature. One such method using …

Everyone Brings Something To The Table: A Culturally Sustaining Analysis Of Teacher Candidates’ Mixed Reality Teaching Simulations, Erin Scott

Faculty Publications

Discussions of HBCU students’ content knowledge have centered around developing high impact, asset-based approaches to learning (Williams et al, 2022). So, HBCU teacher preparation providers (TPPs) can also focus efforts on culturally sustaining approaches to developing candidates’ content knowledge and researching how high impact practices, like teaching simulations, can help prepare candidates for classrooms. This exploratory case study uses critical cases (n=2); findings suggest candidates have a developing understanding of content, which forms a solid basis for increasing their knowledge. MRTSs are addressed as a potential high impact, culturally sustaining practice for building candidates’ content knowledge. Further, HBCU TPPs can …

Multi-Scale Modeling Of Dna-Templated Aggregates For Excitonic Applications, German Barcenas Moncada

Boise State University Theses and Dissertations

Quantum entanglement occupies a central role in the application of quantum mechanics towards emerging technologies of quantum information systems. Meanwhile, quantum entanglement is believed to be observed at room temperature in photosynthetic complexes in plants and algae through the energy transfer of dye molecules. The goal of this project is to engineer dye properties and their arrangement when dyes and aggregates are covalently attached to DNA so that the emergent property of exciton delocalization is as coherent, predictable, detectable and controllable. The creation of such a platform would enable the continued study of near room-temperature quantum entanglement and the more …

Designing An Advanced Gui For A Laser Harp, Matthew Moran

2024 Fall Honors Capstone Projects - Archive

This project presents the design and development of a laser harp, an innovative digital instrument that combines music and technology to inspire interest in STEM education. The harp uses laser beams and phototransistors to simulate the strings of a traditional harp, producing sound when the beams are interrupted. The primary focus of the honors section of this work is a custom-built software interface developed with a graphical user interface (GUI) that allows users to easily adjust settings like note range, volume, and the central part of the show, looping notes. The GUI is designed to be intuitive, making it easy …

Exploring Smart Thermostat, Don P. Dang

2024 Fall Honors Capstone Projects - Archive

This study examines the security, privacy, and compatibility challenges associated with smart thermostats in smart home systems. Smart thermostats, as part of the growing Internet of Things (IoT) ecosystem, face vulnerabilities such as unauthorized access, data breaches, and inconsistent security protocols. Using a mixed-methods approach, this research evaluates encryption techniques, communication protocols (Zigbee, Z-Wave, Wi Fi), and user behaviors that impact system security and efficiency. Key findings indicate that 35% of users are concerned about hacking risks, while 25% express data privacy concerns. Many users lack awareness of security measures, such as firmware updates and password management, which increases vulnerabilities. …

A Machine-Learning Approach To Predicting The Achievement Of Australian Students Using School Climate; Learner Characteristics; And Economic, Social, And Cultural Status, Myint S. Khine, Yang Liu, Vivek K. Pallipuram, Ernest Afari

Pacific Faculty Work

The Programme for International Student Assessment (PISA) is a global survey conducted by the Organisation for Economic Co-operation and Development (OECD) to assess educational systems by evaluating the academic performance of 15-year-old school students in mathematics, science, and reading. In PISA 2022, 13,437 students from Australia participated in the test. While the PISA main questionnaire assesses the subject knowledge, the student background questionnaire solicits contextual information such as school climate, learner characteristics, and socioeconomic status. This study analyses how these contextual variables predict student achievement using the machine-learning models Ridge Linear Regression, K-Nearest Neighbours, Decision Trees, eXtreme Gradient Boosting, and …

Ellipticity-Controlled Exceptional Points From Nanoscale Metasurfaces, Benjamin Goldberg

McKelvey School of Engineering Graduate Student Theses & Dissertations

Precise control over light polarization is critical for advancing technologies in telecommunica- tions, quantum computing, and image sensing. However, existing methods for manipulating polarization around exceptional points in non-Hermitian systems, have exclusively focused on circular polarization and work with reflected light. To address this limitation, we de- velop a novel metasurface platform with high-Q resonators that enables tunable control of polarization exceptional points across arbitrary ellipticity for transmitted light. Our design uses orthogonally polarized guided mode resonators in a two-layer silicon metasurface, where careful tuning of the dipolar guided mode resonances (DGMRs) and layer spacing allows us to control the …

Impact Of Irrigation Systems On Water Use And Water Productivity: A Case Study Using Aquacrop In Khartoum, Sudan, Abdalhakam Almagzoop

Department of Agricultural and Biological Systems Engineering: Masters Project Reports

Water scarcity significantly challenges agricultural productivity in arid regions like Khartoum, Sudan. This study evaluates the impact of three irrigation systems—furrow, sprinkler, and surface drip—on the water use and productivity of sorghum (Sorghum bicolor L.) under different climatic conditions using the AquaCrop model. Simulations were conducted for three representative years: a wet year (2022), a normal year (2015), and a dry year (2018). The results demonstrate that irrigation substantially improved water use efficiency and crop yield compared to non-irrigated (rainfed) conditions. Rainfed crops resulted in lower biomass, harvest index, and yield, particularly in the dry year, highlighting the importance …