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Optimizing Hip And Knee Assistance For Walking And Sit-To-Stand Transitions: An Intrinsic Muscle Mechanics Based Predictive Approach, Neethan Ratnakumar

Dissertations

As the global population ages, the demand for wearable assistive technologies continues to rise, driven by their potential to enhance mobility and independence in older adults. Effectively designed controllers for lower-limb exoskeletons to assist sit-to-stand (STS) and walking are crucial for delivering efficient, safe, and comfortable assistance during daily activities. Traditionally, controller optimization involves biomechanical modeling and user-specific customization. Musculoskeletal simulations play a central role in this process by providing insights into human-exoskeleton interaction dynamics, thereby informing and refining control strategies.

This work presents a simulation-driven approach for developing exoskeleton controllers for walking and STS using two distinct methods: optimal …

Computational Fluid Dynamics (Cfd) Modeling For Bio-Inspired Aerodynamic Optimization In Autonomous Drones, Hyginus C.O. Unegbu, Danjuma Saleh Yawas

Makara Journal of Technology

This study explores the aerodynamic benefits of bio-inspired design modifications for autonomous drones using advanced Computational Fluid Dynamics (CFD) simulations. Four bio-inspired configurations—leading-edge serrations, winglets, riblet surfaces, and curved wings—were assessed and compared against a baseline drone model to evaluate their impact on aerodynamic performance. The results indicated that all bio-inspired designs significantly enhanced lift, reduced drag, and improved overall aerodynamic efficiency. The leading-edge serration configuration achieved the highest performance gains, with a 33.6% increase in maximum lift coefficient (CL) and a 29.5% improvement in lift-to-drag ratio (CL/CD), primarily due to delayed flow separation and reduced turbulence. Winglets minimized wingtip …

Probing The Effect Of Peg-Dna Interactions And Buffer Viscosity On Tethered Dna In Shear Flow, Fatema Tuz Zohra, Huda Al-Zuhairi, Jefferson Reinoza, Hyeongjun Kim, Andreas Hanke

Mechanical Engineering Faculty Publications

DNA flow-stretching is a widely employed, powerful technique for investigating the mechanisms of DNA-binding proteins involved in compacting and organizing chromosomal DNA. We combine single-molecule DNA flow-stretching experiments with Brownian dynamics simulations to study the effect of the crowding agent polyethylene glycol (PEG) in these experiments. PEG interacts with DNA by an excluded volume effect, resulting in compaction of single, free DNA molecules in PEG solutions. In addition, PEG increases the viscosity of the buffer solution. By stretching surface-tethered bacteriophage lambda DNA in a flow cell and tracking the positions of a quantum dot labeled at the free DNA end …

3d-Printable Hydrogel With Rapid Ambient Self-Healing, Anna M. Petre

Research from the Berry Summer Thesis Institute, 2025

Inspired by nature, soft robots composed of compliant (“soft”) materials are well-suited for uncertain, dynamic tasks requiring safe interaction between a robot and its environment. Soft robots with the ability mend minor damage (e.g. perforations, tears) have been enabled by the rapid development of self-healing soft materials. Recently, one of these hydrogel materials (internally dubbed “BeckOHflex”) – made entirely from commercially available precursors – was developed with several appealing characteristics including rapid ambient self-healing, 3D printability on commercial machines, and competitive mechanical properties. However, the self-healing performance of BeckOHflex falls short of competitors that leverage custom-synthesized precursors. This project aims …

Transfer Learning-Based Multi-Sensor Approach For Predicting Keyhole Depth In Laser Welding Of 780dp Steel, Byeong-Jin Kim, Young-Min Kim, Cheolhee Kim

Mechanical and Materials Engineering Faculty Publications and Presentations

Penetration depth is a critical factor determining joint strength in butt welding; however, it is difficult to monitor in keyhole-mode laser welding due to the dynamic nature of the keyhole. Recently, optical coherence tomography (OCT) has been introduced for real-time keyhole depth measurement, though accurate results require meticulous calibration. In this study, deep learning-based models were developed to estimate penetration depth in laser welding of 780 dual-phase (DP) steel. The models utilized coaxial weld pool images and spectrometer signals as inputs, with OCT signals serving as the output reference. Both uni-sensor models (based on coaxial pool images) and multi-sensor models …

Influence Of Obesity On Knee Joint Mechanics: A Subject-Specific Musculoskeletal Modeling Approach, Ryan C. Knowles

Electronic Theses and Dissertations

Obesity has been consistently linked to knee osteoarthritis (KOA), a debilitating joint disease. While prior work has shown that obese individuals often walk with altered biomechanics compared to normal-weight (NW) individuals, which may accelerate KOA progression, less is known about how these mechanics affect load distribution between the medial and lateral tibiofemoral (TF) compartments, particularly during higher-demand activities. This study developed subject-specific musculoskeletal models of five obese and five NW individuals, incorporating CT-based bone measurements and individualized joint contact points. Simulations were driven by six degree-of-freedom (6DOF) kinematics obtained from high-speed stereo radiography (HSSR) to predict TF loading and associated …

Quantify The Impact Of Occupant Behavior On Building Retrofits To Achieve Net-Zero Target Under Future Climates, Pratik Raj Pandey

Dissertations - ALL

It is estimated that about 40% of all the electricity generated in the United States is consumed by the building sector. This scale of energy use by buildings can be understood by the fact that the U.S. alone consumes approximately 20% of all the energy produced globally, despite having only about 4.23% of the world's population. Given the threats posed by climate change, it is necessary to curtail the energy demand of this sector. Additionally, global climate change has increased the frequency, intensity, and duration of extreme climate events like heat waves, cold waves, hurricanes, floods, and droughts. Given the …

Recent Progress And Scientific Challenges In Wire-Arc Additive Manufacturing Of Metallic Multi-Material Structures, Sainand M. Jadhav, Sambhaji Kusekar, Akash Belure, Satyavan Digole, Abhijeet Mali, Muralimohan Cheepu, Manoj Mugale, Suhas Alkunte, Duckbong Kim

Faculty Articles

Metallic multi-material structures are heterogeneous structures characterized by changing composition, microstructures, and site-specific characteristics, advantageous for numerous applications where multifunctionality is desired. Metallic multi-material structures are known as bimetallic structures (BSs), which are functionally graded materials (FGMs). In recent years, wire-arc additive manufacturing (WAAM) advanced as a promising additive manufacturing process to realize the fabrication of these structures due to its high deposition rate, cost-effectiveness, and material utilization efficiency. This review presents a comprehensive overview of the recent progress, processing strategies, and scientific challenges in WAAM of multi-material structures. The paper begins with an introduction to multi-material structures, followed by …

Re-Engaging Driver Attention Using Chatgpt: A Multimodal Study On Stress Impact And Driving Performance, Alaa Zaki Elfiqi

Theses and Dissertations

Driving is considered a complex task that requires continuous focus and attention from the driver. Driving performance can also be impacted by changes in the driver’s stress level. However, limited research explores methods to address this challenge. With the current advances in Large Language Models (LLMs) and their ability to engage in human-like interaction, this study investigates the potential of using ChatGPT, designed to speak Egyptian Arabic, in re-engaging driver attention under different driving scenarios for low-stress and high-stress conditions within a virtual reality (VR) environment driving simulator. Drivers were asked to follow a leading car into two scenarios with …

Ceramic Waste As Sustainable Material In Self-Compacting Concrete: Experimental Study And Ann Predictive Modeling, Abderrezak Bouziane, Houssam Slimanou, Mohamed Amin Bouzidi, Nedjima Bouzidi

Journal of Sustainable Construction Materials and Technologies

Recycling of ceramic waste in the construction sector is a promising option for reducing the environmental impacts of the concrete industry. The main objective of this study is the elaboration of a solid predictive model for ceramic waste based self-compacting (SCC) concrete properties, using artificial neural networks (ANN). This further, reduces its environmental impact without compromising satisfactory performance. An experimental approach was adopted with different substitution ratios: 0 to 30 wt% and particle sizes ranging from 3-8 mm and 8-15 mm. Tested properties of modified SCC as compressive strength at 7 and 28 days (fc7, fc28), spread (L), sieve stability …

Comparative Study On The Performance Of Ggbs, Uggbs, And Rha-Incorporated Cement Mortar Mixes, Devansh Goel, Sudarshan D. Kore

Journal of Sustainable Construction Materials and Technologies

The environmental footprint of cement production has accelerated the pursuit of sustainable alternatives in the construction industry. Supplementary cementitious materials (SCMs), particularly those derived from industrial and agricultural waste, offer a promising approach to reducing cement consumption while maintaining performance. This study evaluates the fresh and mechanical behavior of binary, ternary, and quaternary cementitious mortar blends incorporating ground granulated blast-furnace slag (GGBS), ultrafine GGBS (UGGBS), and rice husk ash (RHA) as partial replacements for cement. A total of 32 mortar mixes were designed with water-to-binder (w/b) ratios ranging from 0.3 to 0.5 and varied replacement levels of RHA (0-20%), GGBS …

Design Of A 10-Ton Capacity Solar-Powered Cold Storage At The Cituis Fish Auction Site, Tangerang, Banten, Indonesia, Wardi Wardi, Muhammad Arif Budiyanto

Journal of Materials Exploration and Findings

This study presents the design of a 10-ton capacity solar-powered cold storage system for the Cituis Fish Auction Site (TPI) in Tangerang, Indonesia, as a sustainable solution to support the coastal fisheries sector. The system comprises two temperature zones: an anteroom at 5°C and a freezer room at -30°C, both integrated with a hybrid system utilizing solar panels and batteries. The total power consumption of the cooling system reaches 27.51 kW. The simulation results, obtained using HOMER Pro software, indicate that the hybrid PV system can reduce CO₂ emissions by up to 16,754 kg per year. From an economic …

Correlation Between Microstructure And Hardfacing Properties With Welding Current Intensity In Reconditioned Low-Alloy Steel Material Using Submerged Arc Welding (Saw) : A Comprehensive Review, Iman Nugraha Asmara, Winarto Winarto

Journal of Materials Exploration and Findings

This review studying the correlation between microstructural transformations and mechanical properties in reconditioned low-allow steel material, focusing on the impact of Submerged Arc Welding (SAW) parameters, especially current, on microstructure . The study highlights how variation on welding parameters, especially current intensity variation, affecting microstructural transformations, hardness, and wear resistance of hardfaced layers. Key aspects such as dilution effect, phases distribution, and carbide formation are reviewed to understanding their impact on mechanical properties. By reviewing insights from existing literature and experimental findings, this review underscores the role of Submerged Arc Welding in enhancing mechanical properties and microstructural of low-alloy steel …

Techno-Enviro-Economic Approach For Electrification Of Rural And Shrimp Farming Regional Development Of An Isolated Island In Indonesia By Utilizing Hybrid Renewable Energy Systems, Fiqih Akbar Wijaya, Mohammad Akita Indianto

Journal of Materials Exploration and Findings

One of the challenges in developing and archipelagic countries such as Indonesia is maintaining energy demand in rural and isolated areas due to difficulties in electrical distribution. For instance, in areas like Bawean Island, no additional electricity capacity has been introduced in the past year, leading to an unmet potential customer demand. One of the possible options is by utilizing Hybrid Renewable Energy Systems (HRES) that are integrated with existing fossil fuel-based energy systems to support the growing energy demand in the remote island. A case study in Bawean Island is conducted with the projected energy demand covers the energy …

Remaining Life Assessment And Fitness For Service Evaluation Of Aging Chemical Reactors In Polyethylene Terephthalate Resin Industry, Aditya Pahlawan Munthe, Donanta Dhaneswara, Wahyuaji Narottama Putra, Gama Widyaputra

Journal of Materials Exploration and Findings

Aging chemical reactors in the polyethylene terephthalate (PET) resin industry require comprehensive evaluation to ensure safe continued operation. This study conducts a remaining life assessment (RLA) and fitness-for-service (FFS) evaluation on five 30-year-old reactors, based on API 510, API 579/ASME FFS-1, and ASME BPVC Section VIII Div. 1 standards. The analysis involves corrosion rate measurement, future corrosion allowance (FCA) projection, and minimum thickness verification. Among the reactors, R-120 was found to have the shortest remaining life less than 15 years. FFS assessments using three criteria Average Measured Thickness, MAWP from Point Thickness Readings, and Minimum Measured Thickness confirm that R-120 …

Implementation Of Reliability Centered Maintenance On Crude Booster Pump, Dzulfikar Ali Hafizh, Maya Agustianingrum Putri St., Ph.D., D. Rizal, Adzra Qanita

Journal of Materials Exploration and Findings

Crude oil booster pump is one of the critical equipment in oil refinery operations. In aging plants that have been operating for more than 25 years, where reliability and maintenance issues on equipment often cause operational disruptions and even unplanned shutdowns. This study aims to develop a structured reliability-centered maintenance (RCM) strategy for crsude oil booster pump systems that is also in line with the principles of asset integrity management system (AIMS). This methodology follows the RCM II approach, starting with system function analysis, failure mode identification, and criticality assessment through Failure Mode, Effect, and Criticality Analysis (FMECA) to determine …

Exploring Different Metal-Oxide Cathode Materials For Structural Lithium-Ion Batteries Using Dip-Coating, David Petrushenko, Thomas Burns, Paul Ziehl, Ralph E. White, Paul T. Coman

Faculty Publications

In this study, a selection of active materials were coated onto commercially available intermediate modulus carbon fibers to form and analyze the performance of novel composite cathodes for structural power composites. Various slurries containing polyvinylidene fluoride (PVDF), active material powders, 1-methyl-2-pyrrolidone (NMP) and carbon black (CB) were used to coat carbon fiber tows by immersion. Four active materials—lithium cobalt oxide (LCO), lithium iron phosphate (LFP), lithium nickel manganese cobalt oxide (NMC), and lithium nickel cobalt aluminum oxide (NCA)—were individually tested to assess their electrochemical reversibility. The cells were prepared with a polymer separator and liquid electrolytes and assembled in 2025-coin …

The Dropbot: Design And Development Of A Custom Drone For Precision Water Drop Penetration Time (Wdpt) Testing, Mugundan Prakash

UNLV Theses, Dissertations, Professional Papers, and Capstones

Assessing the hydrophobic characteristics of soil is vital for understanding soil wettability or soil-water interactions, particularly in post-wildfire environments where water repellency can significantly impact ecosystem recovery, water infiltration, and erosion control. One key metric in soil wettability studies is the Water Drop Penetration Time (WDPT) test, which evaluates the hydrophobicity of soil and guides land treatment strategies. This thesis presents the design and development of DropBot, a custom-built drone platform engineered for the precise delivery and analysis of water droplets in WDPT tests.The DropBot, a custom drone, integrates a lightweight, 3D-printed frame with a self-leveling platform, enabling consistent droplet …

A Study Of Wear Measurement And Life Prediction Of Insert Chute Liner On Gold Ore Processing, Ferry Ardika Natanael, Nony Maulidya, Dedi Priadi

Journal of Materials Exploration and Findings

Chutes are critical materials handling assets to transport solid particles from one process step to another in mineral processing, coal mining and cement industries. The material transport, because of material characteristics, cause severe wear on internal lining of chutes or bins’ structure. The wear problem on internal lining of bins or chutes needs to be checked to keep production efficiency. Therefore, not checked wear rate causes liner replacement schedule becomes unpredictable. It leads to production loss and highly cost maintenance in industry. This study shows that condition-based maintenance through regular thickness measurement using Ultrasonic Transducer (UT) to predict life service …

Analysis Of Leak Testing Planning For Carbon Dioxide Piping Systems In The Development Of Carbon Capture, Utilization, And Storage Facilities In The Bintuni Basin, Devi Sentiani, Akhmad Herman Yuwono Professor

Journal of Materials Exploration and Findings

Carbon Capture, Utilization, and Storage (CCUS) technologies have become a key strategic response to global efforts to reduce CO₂ emissions. This study presents a leak testing strategy designed for a carbon dioxide (CO₂) piping system as part of a Carbon Capture, Utilization, and Storage (CCUS) project in the Bintuni Basin, West Papua, Indonesia. This study aims to ensure the system is properly prepared before commissioning by designing a leak test plan that is both practical and technical, based on ASME B31.3, ASME PCC-2, and API STD 520 Part 1. We conducted the process, which involves identifying the system boundaries, …

Functional Biopolymers Applied To Sustainable Technologies In The Environment And Healthcare, Fengjie He

UNLV Theses, Dissertations, Professional Papers, and Capstones

Biodegradable polymeric materials (biopolymers) are naturally derived materials known for their excellent biocompatibility, biodegradability, sustainability, and versatile chemical functionality. They have attracted increasing attention in various applications as alternative to synthetic materials ranging from food packaging to tissue engineering. Meanwhile, with intrinsic advantages, biopolymers have also emerged as promising materials in addressing contemporary challenges in both biomedical and environmental fields. Motivated by the significant potential of biopolymers and the growing need for sustainable materials, my research focuses on the design and engineering of biodegradable polymers with novel modification methods and application directions. In this work, two representative biopolymers are selected: …

Bio-Inspired Electroactive Polymer (Eap) Sensors For Surface And Canal Flow Sensing In Dynamic Environments, Nazanin Minaian

UNLV Theses, Dissertations, Professional Papers, and Capstones

Nature can often create some of the most efficient and elegant solutions to complex problems, and engineering stands to benefit greatly from these time-tested designs. One of the more sophisticated examples of this is the lateral line system in fish: a distributed network of superficial and canal neuromasts that enables aquatic species to detect fluid disturbances with remarkable precision. This dissertation leverages that biological framework to explore the potential of electroactive polymers (EAPs), aiming not just to replicate structure, but to emulate function.Two classes of EAPs form the basis of this work: electroactive plasticized polymer gels (EPPGs) and ionic polymer-metal …

Nanofluid-Enhanced Hvac&R Systems (2015–2025): Experimental, Numerical, And Ai-Driven Insights With A Strategic Roadmap, Aung Myat, Md Mashiur Rahman, Muhammad Akbar

Mechanical and Manufacturing Engineering Faculty Research

Heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems account for a significant share of global energy demand, prompting intensive research into advanced thermal enhancement techniques. Among these, nanofluids—colloidal suspensions of nanoparticles in base fluids—have shown promise in boosting heat transfer performance. This review provides a structured and critical evaluation of nanofluid applications in HVAC&R systems, synthesizing research published from 2015 to 2025. A total of 200 peer-reviewed articles were selected from an initial pool of over 900 through a systematic filtering process. The selected literature was thematically categorized into experimental, numerical, hybrid, and AI/ML-based studies, with further classification by fluid …

Wear Of High Entropy Alloys: Understanding Effects Of Cryogenic Temperatures And Surface Nitriding On Wear Behavior, Aubrey Yu Tang

Dartmouth College Ph.D Dissertations

Cryogenic tribological applications have become increasingly important with the development and innovation of advanced equipment in aerospace, polar regions, superconductivity, and more. Traditional lubrication methods are not viable under these harsh environments, so metallic materials must be able to maintain excellent mechanical properties and withstand the constant impact and wear alone. High entropy alloys (HEAs) have emerged as potential candidates for these applications because of their wide variety of excellent room temperature properties and apparent improvement of mechanical properties of some HEAs at extremely low temperatures. Despite their promising nature, very limited work has been done on understanding the wear …

Genetic Algorithm Optimization To Maximize Sensitivity Of Triboelectric Mems Accelerometers, Yu Tian, Benyamin Davaji, Shahrzad Towfighian

Mechanical Engineering Faculty Scholarship

A genetic algorithm is used to optimize the sensitivity of a triboelectric MEMS accelerometer fabricated using CMOS-compatible processes. The optimization focuses on the structural parameters of an awl-shaped serpentine microspring (ASSM) connected to the proof mass. Constraints are defined by microfabrication standards and the available chip area. Three different constraint problems are considered, and the algo- rithm yields designs with maximized sensitivity in each case. Simulations under various sinusoidal vibration scenarios show that the optimized designs significantly outperform the previous version, achieving a 2.72× improvement at 1000 Hz and up to 20× at 500 Hz.

Spray Characterization And Fuel Property Analysis Of Tier 3 Gasoline In A Gdi System Using Machine Learning, Kyungwon Lee

Theses and Dissertations

This study investigates the spray behavior of Tier 3 gasoline in gasoline direct injection engines using experimental methods. Tier 3 gasoline, formulated with lower sulfur content, enhances aftertreatment system efficiency and supports cleaner combustion. A comparative fuel property analysis between Tier 3 gasoline and PACE-20, surrogate fuel, was conducted to understand compositional effects on spray. A constant volume spray chamber and optical diagnostics, including diffuse back-illumination extinction, Schlieren, microscopic, and 3D CT reconstruction imaging, were used to examine spray morphology under varying injection conditions. Key spray parameters such as liquid volume fraction, projected liquid volume, droplet size, and cone angle …

Interatomic Potential Of Multiphase Materials Using Modified Embedded Atom Method (Meam) And Artificial Neural Network (Rann), Henan Zhou

Theses and Dissertations

There is a significant need for computer simulations to explore multiphase materials because of their significance in both industry and research. These simulations are both more efficient and less expensive than many experimental approaches, making them an ideal choice for this purpose. It is possible to use molecular dynamics simulations that make use of the MEAM and RANN interatomic potentials in order to comprehend and characterize the properties, performance, and behavior of materials at the atomic scale of different material phases. In the realms of elements, alloys, and impurities, MEAM can be utilized in a wide variety of applications. Through …

Enhanced Nanomechanical, Tribological And Electrical Properties Of Ni-Cr Coatings Via Max Phase Reinforcement And Metallic Interlayers, Mohammad Ashikul Alam

Theses and Dissertations

Nickel-Chromium (Ni-Cr) coatings are widely used in industrial applications due to their resistance to oxidation, thermal stability, and adjustable electrical and mechanical properties. However, achieving improved multifunctional performance across various use cases ranging from extreme tribological environments to microscale device integration remains a significant challenge. This thesis explores two complementary strategies for enhancing the performance of Ni-Cr coatings in both thick and thin film configurations, aiming to address limitations in wear resistance, durability, adhesion, and electrical conductivity. For thick coatings, Ni-Cr was reinforced with Ti3SiC2 MAX phase particles and processed using selective laser sintering (SLS) with optimized parameters. The addition …

Joint Kinematics And Kinetics During Vertical Jump Landings With Progressively Increasing External Loads, Darcie L. Yount

Dissertations

This study examined sagittal and frontal plane kinematics and kinetics during countermovement jump (CMJ) landings performed with either a traditional barbell (BB) or a hexagonal bar (HEX) across increasing submaximal loads in recreationally active males. Generally, hip and knee flexion angles and joint mean angular velocities decreased as loads increased. Hip extension and knee flexion moments increased as load increased up to 20 kg, at which point these values decreased. Performing the CMJ with the HEX exhibited increased frontal plane stability compared with the BB group. Additionally, the BB group exhibited stiffer landing strategies, with decreased sagittal plane joint angles …

Mae Enewsbrief Apr- June 2025, Department Of Mechanical And Aerospace Engineering, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.