Mechanical Engineering Commons^™

Extended Adaptive Oscillator Framework For Gait Phase Estimation With Adaptive Coupling And Transition Detection Across Locomotion Tasks, Nikhila Radha Krishnan

All Theses

Gait phase is a human-inspired physical variable that describes the instantaneous position of a person within a gait cycle. Adaptive oscillators have been widely used for gait phase estimation due to their ability to synchronize with periodic and pseudo-periodic biomechanical signals and generate monotonically increasing cyclic phase values. Typically, the performance of adaptive oscillators is strongly influenced by coupling strength, a parameter that bridges a trade-off between convergence speed and steady-state variability of the estimated stride frequency. In gait assistive applications, stride frequency estimation must be sufficiently fast to enable phase-based assistance while achieving a stable stride frequency estimate. The …

Residual Stress Informed Reconstruction And Failure Analysis Of Manufacturing Induced Composite Meso-Structure, Mohammad Nazmus Saquib

Mechanical & Aerospace Engineering Theses & Dissertations

A physics informed, AI-augmented framework is developed to enable digital twins of molded composite materials by linking manufacturing induced residual stresses to a local meso-structure. By reconstructing and explicitly modeling these architectures, the framework reveals how processing driven meso-structural variability governs stiffness, damage evolution, and failure. The work focuses on two technologically important systems: prepreg platelet molded composites (PPMC), characterized by inherently stochastic platelet architectures, and 2/2 twill glass fiber/PA6 organosheets, whose periodic but locally variable weave geometry influences mechanical response. For PPMC, the Residual Stress Informed Microstructure Reconstruction (ResIMiR) framework is introduced, combining thermoelastic strain fields with deep learning …

Toward Risk-Informed Design Of Supercooling Heat Exchangers: Statistical Inference And Experimental Investigation Of Heterogeneous Ice Nucleation, Daniel B. Gardner

All Graduate Theses and Dissertations, Fall 2023 to Present

Ice-based cooling storage systems can reduce electricity costs and grid strain by making ice during off-peak hours and using it for air conditioning during the day. One promising design works by chilling water below its freezing point as it flows through a heat exchanger, then allowing it to freeze in a separate storage tank. The challenge is that the chilled water can freeze prematurely inside the heat exchanger itself, blocking the flow and shutting the system down. Preventing this unwanted freezing requires understanding how and where ice begins to form on surfaces, a process called nucleation.

This dissertation investigates ice …

Water-Heated Maisotsenko Cycle Humidifiers: A Component-Level Study On Evaporation And Exit Brine Concentration, Omar Abdulfattah Farag Omar A. Farag

Renewable Mechanical Energy

Maisotsenko-cycle (M-cycle) Heat-and-Mass Exchangers (HMXs) are usually assessed as part of complete cooling or desalination systems, which makes the behaviour of the humidifier itself difficult to distinguish. Here, a validated model is used to examine a water-heated M-cycle humidifier as an independent component. Inlet saline-water temperature, ambient temperature, Relative Humidity (RH), and water-to-air Mass-flow Ratio (MR) were varied, and performance was described by Water Evaporation Rate (WER), outlet-air specific humidity, and outlet brine salinity. Water heating and a larger MR produced the strongest increase in moisture addition because they maintained a warmer water film and greater transfer potential. At fixed …

A Thickness-Invariant Origami Robot With Integrated Actuation And Multimodel Locomotion, Larry L. Howell, Davis Wing, Nathan Usevitch, Sam Bridge, William Bowler

Faculty Publications

ABSTRACT Origami robots possess the potential for advanced reconfigurability in various contexts and environments. This paper describes and demonstrates the function of an origami robot following a thickness-invariant version of the Yoshimura tessellation. This thickness-invariance allows for the simple folding pattern to be expanded vertically, allowing all robotics components to be housed within the panels of the robot without impacting the functional relationships between folds of the pattern, or requiring other, more complex forms of thickness accommodation. The mathematics and engineering to create such a robot are presented to enable the use of these techniques in creating other origami-based robots. …

Thermal Degradation Analysis Of Bagasse Fibers From Sugarcane Waste, Rashmitha Suresh, Faisal Al Nasser

Journal of Mechanical Engineering Science and Technology (JMEST)

Sugarcane is one of the important commodities in the industry where bagasse fiber as waste is abundantly available.   Sugarcane bagasse fiber has high cellulose, a key element in the utilization of bagasse. Chemical pretreatment is important to prepare the natural fiber before used as composite reinforcement. The purpose of the study is to analyze the thermal degradation of bagasse fiber after being treated using NaOH and TEMPO solution. The manufacturing method was carried out by a series of washing bagasse with distilled water and NaOH solution, subsequently soaking it in 6% NaOH and 2,2,6,6-tetramethylpiperidine-l-oxyl (TEMPO) solution, and conducted oven-dried. Thermogravimetric …

Emergent De Sitter Expansion And Closed Topology From The Cosmic Fabric Model As An Open Thermodynamic System: Resolving The Negative Bulk Modulus Paradox, T G. Tenev, C B. Ward, T F. Tenev, M F. Horstemeyer

Faculty Publications and Presentations

The Cosmic Fabric Model establishes a continuum-mechanics isomorphism to General Relativity by representing physical space as an elastic three-dimensional hyperplate embedded in a four-dimensional spatial bulk. Reproducing vacuum kinematics requires a vanishing P-wave modulus, which in turn implies a negative bulk modulus—an apparent thermodynamic instability in a closed system. This paradox is resolved by recasting the framework as an open system: the instability is not pathological but instead drives cosmic expansion. In this interpretation, the observable universe is a lower-energy solid formed through continuous solidification from a higher-dimensional precursor fluid. Using multiplicative kinematics from finite-growth mechanics, the model shows that …

Developing Simulation To Improve G3p3 Efficiencies, Andrew Gaudette

Mechanical Engineering ETDs

Concentrated solar power (CSP) systems offer a promising method of renewable energy generation by using heliostats to focus sunlight onto a falling particle receiver. At the National Solar Thermal Testing Facility (NSTTF), particles absorb and store solar energy for later power generation. A major source of efficiency loss is wind-driven particle escape through the receiver aperture. This thesis develops computational fluid dynamics (CFD) simulations to characterize wind flow around the G3P3 falling particle receiver and support future wind mitigation strategies. Numerical studies were conducted to establish an appropriate simulation methodology. Iteration studies showed that 2,000 iterations were sufficient for convergence, …

Control Of Reshock In A Shock Tube, Alexander Sweis

Mechanical Engineering ETDs

Reshocks can pose a threat to the structural integrity of structures and buildings. While incident shock waves pose larger threats, the study of reshocks and reshock attenuation is important to consider. This thesis investigates methods for controlling and attenuating reshock strength within a shock tube through material-based damping and modifications to baffle box geometric configurations. Experiments are performed using a custom-built shock tube in the University of New Mexico fluid mechanics laboratory. Four baffle box configurations are examined: a foam-lined configuration, a foam-lined configuration with ”egg crate-like” textured foam, an empty (no foam) configuration, and a configuration which incorporates a …

Development Of Dynamic Proof-Mass Configurations For Broadband Piezoelectric Energy Harvesting, Nico E. Galarza

Electrical and Computer Engineering ETDs

The purpose of this thesis is to investigate and develop dynamic proof-mass configurations for broadband piezoelectric energy harvesting. Conventional piezoelectric energy harvesters are typically limited by narrow operating bandwidths, restricting their performance under variable-frequency excitation. This research presents the design, fabrication, and experimental evaluation of multiple proof-mass concepts intended to increase the usable frequency range of cantilever-based piezoelectric energy harvesters. Several dynamic mass configurations were developed using additive manufacturing techniques and integrated with commercially available piezoelectric cantilevers. Experimental testing was conducted under controlled vibration conditions to characterize voltage response, resonant behavior, and bandwidth performance. The results demonstrate that dynamic proof-masses …

Investigating Light-Matter Interactions In Low-Dimensional Silicon Carbide, Nishan Shrestha

Mechanical Engineering ETDs

Recent advances in materials science have transformed the study and application of low-dimensional materials, with two-dimensional (2D) systems and nanoscale structures exhibiting properties beyond their bulk counterparts. Despite significant progress in materials such as graphene and silicon, the nanoscale exploration of silicon carbide (SiC) remains relatively underdeveloped, despite its critical importance in photonics and electronics and high temperature applications. Motivated by the transformative potential of nanoscale material design and the technological importance of SiC, this dissertation investigates structure and properties of low-dimensional silicon carbide structures. It explores the synthesis and optical properties of SiC nanosheets and nanowires using a variety …

Analysis Of Electronic Control Unit Optimization On The Performance Of A 150 Cc Motorcycle Engine Using Ethanol-Blended Fuel, Agus Achmad Syaiful, Annisa Bhikuning, Muhammad Rizal Baihaqi, Muhammad Aulia Rafli

Journal of Mechanical Engineering Science and Technology (JMEST)

The use of ethanol-blended fuel in a standard vehicle can reduce combustion quality, which has an impact on decreasing vehicle performance. At the above 20% blend level, it affects vehicle performance and requires adjustments to engine settings or the Electronic Control Unit (ECU) before use on conventional engines. This study investigates the effect of aftermarket ECU settings on the performance of a 150 cc motorcycle operating on a gasoline-ethanol blend. Four fuel variations were tested: Pertalite (P100), revvo 90 (R100), and 30% ethanol blends (PE30 and RE30). This study analyzes the effects of optimizing injection duration and ignition timing settings …

Object Avoidance Onboard An Autonomous Underwater Vehicle In Support Of Geomagnetic Based Navigation System, Eric Benavidez

Electronic Theses and Dissertations 2020 - Present

The objective of this thesis was to collect and analyze magnetic field data in the vicinity of the Mercy, Tracey, and Jay Scutti with an autonomous underwater vehicle (AUV) and a forward mounted magnetometer. The collected data was used to develop geomagnetic contour maps and magnetic thresholds of known anomalies to compare the results with validated sources such as NOAA.

In addition, this collected data was used to develop a Gazebo simulation which accurately modeled the magnetic field data and ocean effects of the Fort Lauderdale Shipwreck Trail. This Gazebo simulation allowed for proper testing and refinement of object avoidance …

Chemical Composition Stability Of Cu–Sn And Cu–Zn Journal Bechemical Composition Stability Of Cu–Sn And Cu–Zn Alloys Fabricated By Sand And Permanent Mold Casting With Nickel Alloying, Erwin Erwin, Didik Sugiyanto, Juan Pratama, Trisna Ardi Wiradinata, Abdul Rachmadhan, Muhammad Fikri Andika

Journal of Mechanical Engineering Science and Technology (JMEST)

The processes of moulding and reinforcing chemical elements have a big impact on the balance of chemical composition in copper-based bearing alloys. This has a direct impact on how well the material works. This study examines Cu–Sn alloys produced via sand casting and Cu–Zn alloys fabricated through permanent mould casting, with the incorporation of nickel, which remains uncommon. The objective was to examine the variations in the equilibrium of the chemical composition and the performance potential of the bearing alloy metal when subjected to different casting techniques and nickel concentrations ranging from 0% to 4%. Some of the methods used …

Effect Of Concentration And Temperature Of Tio2-Al2o3 Hybrid Nanofluid On The Corrosion Rate Of Aluminum Radiator, Ratna Monasari, Rizky Maulana Ramadhan, Nike Nur Farida, Ahmad Hanif Firdaus, Supa Kusuma Aji, Yuniarto Agus Winoko, Rizkyansyah Alif Hidayatullah

Journal of Mechanical Engineering Science and Technology (JMEST)

Corrosion of aluminum radiators can reduce cooling system reliability and shorten service life in automotive applications. This study examines the effect of TiO₂-Al₂O₃ hybrid nanofluid concentration and temperature on the corrosion rate of commercially available aluminum radiator material. Hybrid nanoparticles with a TiO₂-Al₂O₃ mass ratio of 50:50 were dispersed in distilled water at concentrations of 0.6 wt.%, 0.8 wt.%, and 1.0 wt.%. Corrosion behavior was evaluated using a 14-day accelerated immersion test at 60°C and 80°C, and the corrosion rate was determined using the gravimetric mass loss method. The results …

Experimental Evaluation Of Membranes In The Recovery Of Hydrogen From Serpentinization, Rafael Dos Santos

LSU Master's Theses

Natural hydrogen generated through serpentinization reactions has emerged as a promising low-carbon energy resource. However, serpentinization-derived gas streams commonly contain methane (CH₄) and carbon dioxide (CO₂), requiring purification before hydrogen can be utilized in industrial applications. Membrane-based gas separation technologies offer a potentially cost-effective solution for hydrogen recovery; however, to the best of the author's knowledge, no previous studies have specifically investigated their application to serpentinization-derived gas streams.

This work evaluates the performance of two commercial polymeric membrane modules (Evonik and Generon) and one palladium-copper (Pd-Cu) membrane module (Okaya) for hydrogen recovery from gas compositions representative of serpentinization environments. An …

Global Time-Resolved Measurements Of Inlet/Isolator Unstart Induced By Mass Injection, Andrew N. Bustard, Benjamin L. Bemis, Aaron Marques, Matthew J. Zahr, Thomas J. Juliano

Publications

The inner surface pressure of an axisymmetric inlet/isolator model was measured using anodized-aluminum pressure-sensitive paint (PSP) viewing through cast acrylic. Temperaturesensitive paint was utilized to correct for the PSP’s temperature sensitivity. The model was tested under Mach 5.7 flow at 𝑹𝒆 = 7.1 ×106 /m under conventional noise conditions. Transverse jet injection with jet-to-inlet mass-flow ratios up to 0.8 was used to induce unstart in the inlet/isolator. Background-oriented schlieren visualization of the inlet shocks was collected simultaneously with the PSP to determine when the inlet unstarted. Computational fluid dynamics results were used to determine off-wall flow structures and quantify approach …

Straw As A Potential Vegetable Fibre Insulative Infill In Framed Constructions - Material Testing\Tnotereftnote1, Patrick Daly

Journal of Sustainable Construction Materials and Technologies

The construction sector faces increasing pressure to reduce embodied carbon and adopt circular material strategies, with bio-based materials offering a promising pathway. Straw-based insulation, particularly in loose-fill form, has gained traction in Europe, where several products have achieved certification under EAD 040138-01-1201. This study investigates the potential of Irish-processed straw chip as a bio-based insulative infill for framed construction by evaluating its material properties and thermal conductivity–density performance relative to European ETA-certified reference products. A programme of laboratory testing was undertaken on commercially available Irish straw samples, including material characterisation (moisture content, particle morphology, and dust content) and thermal conductivity …

Development And Characterization Of Mycelium-Based Biocomposites From Ganoderma Lucidum Using Spent Yerba Mate And Residual Sunflower Oil For Sustainable Insulation In Construction, Paula V. Alfieri, Guadalupe Canosa

Journal of Sustainable Construction Materials and Technologies

The construction industry urgently requires sustainable alternatives to petroleum-based insulation materials such as expanded polystyrene (EPS) and mineral wool. Mycelium-based biocomposites offer a promising solution by valorizing agricultural waste while delivering competitive thermal and acoustic performance. In this study, developed and characterized biocomposites using Ganoderma lucidum mycelium combined with spent yerba mate and residual sunflower oil (70 g/30 mL), both commonly generated as waste in Argentine institutions. Two formulations were evaluated: high density (HD: 280 ± 5 kg/m³) and low density (LD: 185 ± 5 kg/m³). Samples were cultivated for 90 days at 28 °C and 65% relative humidity and …

Comparative Life Cycle Assessment Of Hemp Walls In Residential Construction In Morocco, Hicham Kaddouri, Rachida Elbarghmi, Firyal Latrache, Marwane Hammouti, Abderrahim Abidouche, Ismael Driouch

Journal of Sustainable Construction Materials and Technologies

This study analyzes the energy and environmental performance of hemp-based wall solutions applied to Moroccan residential buildings by combining dynamic thermal simulation and life cycle assessment (LCA). A reference building is assessed under four representative Moroccan climates (Al Hoceima, Oujda, Marrakech, and Ouarzazate), comparing a conventional wall retrofitted with hemp plaster and a wall incorporating hemp concrete. The results show that hemp concrete significantly reduces annual heating and cooling energy demands by 20–24% depending on the climate, with heating needs decreasing by up to 40% and cooling needs by approximately 15%, particularly in hot and arid regions. The LCA reveals …