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Articles 1 - 30 of 657
Full-Text Articles in Mechanical Engineering
Review: Mechanics Of Mycelium Materials, Md Anwar Sadat Anik, Ehsanul Azim, Gerardo I. Zapata, Mohammad R. Islam
Review: Mechanics Of Mycelium Materials, Md Anwar Sadat Anik, Ehsanul Azim, Gerardo I. Zapata, Mohammad R. Islam
Mechanical Engineering Faculty Publications
The biological growth of fungal root structure, called mycelium, can be engineered to develop innovative fibrous and biocomposite materials. Mycelium materials have potential as sustainable alternatives to petroleum-derived materials for load-bearing applications. To realize this potential, there is an increasing effort dedicated to understanding the mechanics of mycelium materials. This work presents a systematic review of our current understanding of the mechanics of mycelium materials with a specific focus on structure–property relationships. The review first explores how the mycelium’s fiber network structure varies depending on whether it is grown as a two-dimensional (2D) membrane, a cellular foam, or as a …
Analysis Of The Fracture Toughness Of Ercual A2 Cladding On Api X70 Using The Instrumented Charpy Impact Test, Martín Aguirre-Pulido, Francisco Fernando Curiel-López, Jose Jaime Taha-Tijerina, Jorge Alejandro Verduzco-Martínez, Víctor Hugo López-Morelos, Heriberto Granados-Becerra, Ariosto Medina-Flores
Analysis Of The Fracture Toughness Of Ercual A2 Cladding On Api X70 Using The Instrumented Charpy Impact Test, Martín Aguirre-Pulido, Francisco Fernando Curiel-López, Jose Jaime Taha-Tijerina, Jorge Alejandro Verduzco-Martínez, Víctor Hugo López-Morelos, Heriberto Granados-Becerra, Ariosto Medina-Flores
Mechanical Engineering Faculty Publications
The degradation of steel used in the oil industry has become a serious problem due to the high costs associated with material loss from corrosion. Applying thin layers of corrosion-resistant material promises to be a viable alternative for extending the service life of pipelines. ERCuAl-A2 electrode claddings were applied to API X70 carbon steel using the MIG brazing process with direct current (DC) and pulsed current (P). The cladding was applied under three conditions: base material (BM) at room temperature, BM preheated to 120 °C, and Ni-buttered BM. Microhardness profiles and Charpy impact tests were performed on the MB and …
Effect Of Heat Treatments On The Corrosion Resistance Of A Trip Steel And Its Evaluation By Non-Destructive Testing, Karla Ivette Vega-Nava, Ariosto Medina-Flores, Marco Antonio Espinosa-Medina, José Sergio Pacheco-Cedeño, Héctor Guillermo Carreón-Garcidueñas, Francisco Fernando Curiel-López, Jose Jaime Taha-Tijerina
Effect Of Heat Treatments On The Corrosion Resistance Of A Trip Steel And Its Evaluation By Non-Destructive Testing, Karla Ivette Vega-Nava, Ariosto Medina-Flores, Marco Antonio Espinosa-Medina, José Sergio Pacheco-Cedeño, Héctor Guillermo Carreón-Garcidueñas, Francisco Fernando Curiel-López, Jose Jaime Taha-Tijerina
Mechanical Engineering Faculty Publications
The development of advanced high-strength steels (AHSS) for the automotive industry requires optimizing the balance between mechanical properties and durability in aggressive environments. This study investigates the effects of two heat treatment routes on the microstructure and corrosion resistance of a transformation-induced plasticity (TRIP) steel (Fe-0.2C-1.75Mn-0.5Si-1Al). Route A includes a full austenitizing step at 1000 °C prior to intercritical annealing, whereas Route B omits this step and begins directly with intercritical annealing at 800 °C. Microstructural characterization (SEM/XRD), electrochemical assays, and eddy current tests were employed. The results revealed that Route A yields a homogeneous microstructure with 12.7% retained austenite, …
Centrifugally Spun Silica Fibers For Lithium-Ion Battery Anodes: Structure And Cycling Stability, Alejandra Guerrero, Valeria Tirado, Jason Parsons, Mataz Alcoutlabi
Centrifugally Spun Silica Fibers For Lithium-Ion Battery Anodes: Structure And Cycling Stability, Alejandra Guerrero, Valeria Tirado, Jason Parsons, Mataz Alcoutlabi
Mechanical Engineering Faculty Publications
Introduction: Silicon dioxide (SiO2) fiber structures have attracted attention as alternative anode materials for lithium-ion batteries because of their ability to improve cycling stability compared to commercial silicon particles.
Materials and methods: SiO2 composite fibers were prepared by centrifugal spinning of polyvinylpyrrolidone (PVP)/SiO2 precursor solutions followed by calcination at 500–700 ◦C for different holding times to produce short-fiber composites and micro-belt SiO2 fiber structures. The morphology and crystal structure of the SiO2 short fibers and micro-belts were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). Electrochemical performance was evaluated using CR2032 half-cells.
Results: The …
A Novel Hexagonal-Zigzag Cellular Infill Structure For Additive Manufacturing, Md. Saidur R Roney, Amm Nazmul Ahsan, Prosenjit Barua
A Novel Hexagonal-Zigzag Cellular Infill Structure For Additive Manufacturing, Md. Saidur R Roney, Amm Nazmul Ahsan, Prosenjit Barua
Manufacturing & Industrial Engineering Faculty Publications
The rigidity of the Additively Manufactured objects can be tailored by manipulating the infill lattice type and density. In this research, an island type novel infill structure termed as Hexagonal-Zigzag pattern is introduced, and its mechanical performance is investigated. In this pattern, the zigzag raster reflects the repeating hexagonal shaped cell constituting the parallel-oriented islands and 90° rotation of the pattern in each layer distributes the island span along both transverse and longitudinal directions of the printing contour. A mathematical model is established to illustrate the effect of the infill parameters on hexagon unit cell size and relative infill density. …
Enhanced Triboelectric Effect Using Functionalized Multiwalled Carbon Nanotube-Coated Fiber Mats For Biomechanical Energy Harvesting, Fernando Viesca, Diego De Leon, Kevin Alejandro, Rigobert Ybarra Jr., Md. Wasikur Rahman, Victoria Padilla, Horacio Vasquez, Karen Lozano, M. Jasim Uddin
Enhanced Triboelectric Effect Using Functionalized Multiwalled Carbon Nanotube-Coated Fiber Mats For Biomechanical Energy Harvesting, Fernando Viesca, Diego De Leon, Kevin Alejandro, Rigobert Ybarra Jr., Md. Wasikur Rahman, Victoria Padilla, Horacio Vasquez, Karen Lozano, M. Jasim Uddin
Mechanical Engineering Faculty Publications
Triboelectric nanogenerators (TENGs) have emerged as a cutting-edge technology for developing self-powered wearable electronic devices. In this study, TENGs were fabricated using two fiber mats: forcespun polytetrafluoroethylene (FS-PTFE) microfibers and electrospun polyvinyl alcohol (ES-PVA) nanofiber (NF) mats. The FS-PTFE mats were coated with functionalized multiwalled carbon nanotubes (MWCNTs). Functionalized MWCNTs were dispersed in water-based solutions containing three different surfactants—sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, and Triton X-100 to enhance fiber interaction. The NF mats were subsequently immersed in aqueous systems. The surfactant facilitated the uniform deposition of COOH-MWCNTs onto the FS-PTFE fibers, serving as a negative layer, while ES-PVA mat …
Data Driven Estimation Of Pore Size Using 1d Light Emissions For Laser Powder Bed Fusion Additive Manufacturing, Jose Galarza, Jorge Barron, Luis Jimenez, Tamer Oraby, Jianzhi Li, Farid Ahmed
Data Driven Estimation Of Pore Size Using 1d Light Emissions For Laser Powder Bed Fusion Additive Manufacturing, Jose Galarza, Jorge Barron, Luis Jimenez, Tamer Oraby, Jianzhi Li, Farid Ahmed
Manufacturing & Industrial Engineering Faculty Publications
The quality assurance of the Laser Powder Bed Fusion Process (LPBF) has been extensively investigated over the last decade for in-situ monitoring of metal additive manufacturing. The process inherently generates voids within the bulk of the part, which can detrimentally affect the quality of the printed part. The characterization of these voids by estimating their size and identifying their geometrical features remains a challenge. This study introduces a Machine Learning (ML) based framework for estimating void sizes of varying geometries using layer-wise one-dimensional (1D) average light intensity signal obtained from the optical tomography system during the 3D printing of metallic …
Decomposition And Spectral Characterization Of Unsteady Loads In Pulse-Jet Propulsion Testing, Cesar Benitez
Decomposition And Spectral Characterization Of Unsteady Loads In Pulse-Jet Propulsion Testing, Cesar Benitez
Theses and Dissertations
Pulsed jet propulsion systems produce inherently unsteady forces whose time-resolved characterization is essential for performance assessment, yet the measured load signal conflates aerodynamic forcing with the dynamic response of the measurement balance itself. This thesis develops a load centered framework for the dynamic characterization of a pulsed jet system, treating the measured load fluctuation as the primary physical observable rather than attempting full true-thrust reconstruction. A single-degree-of-freedom balance model identified through ringdown testing provides the structural reference scale, yielding a natural frequency of 8.5 Hz and damping ratio of 18%. Power spectral density, phase-averaging, and synchronous–residual decomposition is applied uniformly …
Examining The Effects Of Lateral Loading On Railroad Tapered Roller Bearings, Abel David Sanchez Trinidad
Examining The Effects Of Lateral Loading On Railroad Tapered Roller Bearings, Abel David Sanchez Trinidad
Theses and Dissertations
The loading conditions experienced by freight railcar bearings vary as a function of vehicle operating conditions. Under static conditions, bearings are primarily subjected to radial loads transmitted through the wheelset. During operation, however, track irregularities, braking events, railcar load imbalances, and curving introduce complex impact, longitudinal, and lateral forces in addition to the normal radial loading. These lateral forces increase friction within the bearing raceways, which could accelerate wear and potentially lead to premature spall initiation and propagation. While prior research at the University Transportation Center for Railway Safety (UTCRS) has demonstrated that vibration signatures can be used to detect …
Unveiling Value In Plastic Waste: Synthesis Of 1,3-Dioxolan-4-Ones From Polylactic Acid And Polyoxymethylene To Enhance Plastic Biodegradation, Mi-Hyun Lee, Joohyun Park, Hyeongyeong Lee, Woo Yeon Cho, Semin Son, Pyung Cheon Lee, In-Hwan Lee, Hye-Young Jang
Unveiling Value In Plastic Waste: Synthesis Of 1,3-Dioxolan-4-Ones From Polylactic Acid And Polyoxymethylene To Enhance Plastic Biodegradation, Mi-Hyun Lee, Joohyun Park, Hyeongyeong Lee, Woo Yeon Cho, Semin Son, Pyung Cheon Lee, In-Hwan Lee, Hye-Young Jang
Mechanical Engineering Faculty Publications
Catalytic plastic upcycling protocols are essential for resolving the environmental and economic challenges associated with massive plastic production and disposal, as they convert complex waste streams into value-added chemicals. We report an efficient acid-catalyzed upcycling strategy for transforming poly(lactic acid) (PLA) and polyoxymethylene (POM) plastic waste. This innovative process directly yielding dioxolanones (DOXs) can be extended to use POM with various naturally abundant α-hydroxy acids. This work significantly expands the high-value chemical portfolio derivable from common plastic wastes. Incorporation of the synthesized DOXs into the poly(L-lactic acid) (PLLA) backbone results in materials with enhanced thermal stability and superior biodegradability. Critically, …
Investigation Of Process Parameters To Fabricate Tiwmo Refractory Medium Entropy Alloy Via Laser Powder Bed Fusion, Abdullah Al Masum Jabir, Lindsey A. Salazar, Jianzhi Li
Investigation Of Process Parameters To Fabricate Tiwmo Refractory Medium Entropy Alloy Via Laser Powder Bed Fusion, Abdullah Al Masum Jabir, Lindsey A. Salazar, Jianzhi Li
Manufacturing & Industrial Engineering Faculty Publications
This paper presents an experimental study on the fabrication of a TiWMo refractory medium-entropy alloy (RMEA) using laser powder bed fusion (PBF-LB/M, commonly known as selective laser melting) from elemental powders as well as successful alloy formation on titanium substrates. The effects of tungsten particle size and process parameters on successful TiWMo RMEA fabrication have been explored using scanning electron microscopy (SEM), x-ray diffraction, hardness measurement and microstructural analysis. Scanning electron microscope (SEM) analysis revealed that the lowest percentage (0.01%) of unmelted tungsten particles was observed at a laser power of 350 W and scanning speed of 250 mm/s, particularly …
Layer-Wise Printing Parameter Optimization For Laser Powder Bed Fusion, Chaoran Dou, Rongxuan Wang, Raghav Gnanasambandam, Jianzhi Li, Zhenyu James Kong
Layer-Wise Printing Parameter Optimization For Laser Powder Bed Fusion, Chaoran Dou, Rongxuan Wang, Raghav Gnanasambandam, Jianzhi Li, Zhenyu James Kong
Manufacturing & Industrial Engineering Faculty Publications
Additive manufacturing (AM) is a transformative technology that enables the fabrication of complex geometries layer by layer. However, metal parts produced via AM processes such as laser powder bed fusion (LPBF) are prone to various defects, including porosity and deformation. These defects often result from suboptimal printing parameter settings. Traditional approaches typically aim to reduce defects by optimizing a fixed set of parameters for the entire part. However, such methods do not account for layer-wise variations in printing conditions caused by changes in geometry, heat transfer, and re-heating effects. While optimizing parameters for each layer could improve part quality, it …
Reinforcement Learning For Imbalanced Data In Robotic Anomaly Detection Within Autonomous Manufacturing, Salma Messaoudi, Ahmed Bendaouia, El Hassan Abdelwahed, Mohammed Ameksa, Hajar Mousannif, Jianzhi Li
Reinforcement Learning For Imbalanced Data In Robotic Anomaly Detection Within Autonomous Manufacturing, Salma Messaoudi, Ahmed Bendaouia, El Hassan Abdelwahed, Mohammed Ameksa, Hajar Mousannif, Jianzhi Li
Manufacturing & Industrial Engineering Faculty Publications
Ensuring reliable anomaly detection in industrial robots is critical for safe and autonomous manufacturing operations. However, it remains challenging due to temporal dependencies and class imbalance in sensor data. This study presents a reinforcement learning approach using Deep Q-Network (DQN) enhanced with Long Short-Term Memory (LSTM) and Gradient Boosting Machine (GBM) for robust anomaly detection in robotic systems. The proposed framework integrates an LSTM into the DQN policy to capture temporal patterns. It also introduces a novel GBM-based reward mechanism that mitigates class imbalance by applying SMOTE (Synthetic Minority Over-sampling Technique) after removing temporal dependencies. Experimental results demonstrate that this …
Thermal Management And Lubrication Characteristics Of Tungsten Disulfide (Ws2) Vegetable-Based Nanolubricants, Jaime Taha-Tijerina, Dyana De Leon-Elizondo, Jade Mendieta, Leonardo Taha-Soto
Thermal Management And Lubrication Characteristics Of Tungsten Disulfide (Ws2) Vegetable-Based Nanolubricants, Jaime Taha-Tijerina, Dyana De Leon-Elizondo, Jade Mendieta, Leonardo Taha-Soto
Informatics and Engineering Systems Faculty Publications
Recent innovations with the aid of nanotechnology are more frequently seen in the industrial sectors. Lubricants are a high-end commodity resource used in many manufacturing processes; unfortunately, most of these lubricants are petroleum-based, which come with certain drawbacks, such as environmental aspects, handling issues and high costs. With the incorporation of nanostructures within fluids and lubricants, novel material alternatives are replacing conventional lubrication systems, maintaining the required thermophysical and tribological characteristics. This research provides an analysis of vegetable lubricant, castor oil (CO), and the effects of the incorporation of WS2 nanofiller at diverse filler fractions. A TEMPOS thermal analyzer device …
Tribological Properties Of Aisi 420 Esr Stainless Steel Modified By Sequential Boriding And Nitriding, Melvyn Alvarez Vera, Rafael Carrera Espinoza, Valeria López López, Marc Wettlaufer, Stefan Barth, Juan Carlos Díaz Guillén, Héctor Manuel Hernández García, Rita Muñoz Arroyo, Javier A. Ortega, Marco A. Cruz-Gómez
Tribological Properties Of Aisi 420 Esr Stainless Steel Modified By Sequential Boriding And Nitriding, Melvyn Alvarez Vera, Rafael Carrera Espinoza, Valeria López López, Marc Wettlaufer, Stefan Barth, Juan Carlos Díaz Guillén, Héctor Manuel Hernández García, Rita Muñoz Arroyo, Javier A. Ortega, Marco A. Cruz-Gómez
Mechanical Engineering Faculty Publications
This study investigates the effects of surface thermochemical treatments using boriding, nitriding, and boronitriding on the microstructure and mechanical properties of martensitic stainless steel AISI 420 ESR. Powder-pack boriding, gas nitriding, and sequential boronitriding processes were applied to enhance surface hardness, wear resistance, and adhesion. The microstructural and mechanical properties of the surface samples were analyzed using scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, microhardness, and nanoindentation testing. Tribological behavior was analyzed using a pin-on-disk tribometer under dry-sliding wear conditions, with applied normal loads of 5 N and 10 N and a sliding distance of 1000 m. The results showed …
Artificial Intelligence And Additive Manufacturing As A Coupled Design System: Rethinking Inference, Manufacturability, And Design Education, Charul Chadha, Garth Crosby, Sabit Ekin, Mohamed Gharib, Eman Hammad, Congrui Jin, Ali Ahmad Malik, Noemi Mendoza Diaz, Calahan Mollan, Monsuru Ramoni
Artificial Intelligence And Additive Manufacturing As A Coupled Design System: Rethinking Inference, Manufacturability, And Design Education, Charul Chadha, Garth Crosby, Sabit Ekin, Mohamed Gharib, Eman Hammad, Congrui Jin, Ali Ahmad Malik, Noemi Mendoza Diaz, Calahan Mollan, Monsuru Ramoni
Manufacturing & Industrial Engineering Faculty Publications
Artificial intelligence (AI) is becoming deeply integrated into additive manufacturing (AM) workflows, reshaping how designers approach geometry, materials, and process constraints. AI holds significant potential by accelerating design exploration, revealing complex patterns in AM behavior, and supporting earlier assessment of manufacturability. At the same time, it introduces new risks related to model transparency, data quality, physical validity, and the potential for overreliance by students and practitioners. This perspective examines these issues through four guiding questions that address the role of AI in AM-enabled design, the gaps that limit or enable AI contribution, the implications for engineering education, and the responsibilities …
Patient‐Specific Computational Flow Simulation Reveals Adverse Hemodynamic Factors Associated With Occlusion Of Directional Branches After Fenestrated‐Branched Endovascular Aneurysm Repair, Kenneth Tran, Jesse Chait, Emmanuel Tenorio, Weiguang Yang, Alison Marsden, Bernardo Mendes, Jason T. Lee, Gustavo S. Oderich
Patient‐Specific Computational Flow Simulation Reveals Adverse Hemodynamic Factors Associated With Occlusion Of Directional Branches After Fenestrated‐Branched Endovascular Aneurysm Repair, Kenneth Tran, Jesse Chait, Emmanuel Tenorio, Weiguang Yang, Alison Marsden, Bernardo Mendes, Jason T. Lee, Gustavo S. Oderich
Mechanical Engineering Faculty Publications
Background: Fenestrated and branched endovascular aneurysm repair can be complicated by branch vessel occlusion in the absence of structural stenosis. We hypothesized that computational flow simulation could identify adverse hemodynamic features associated with postfenestrated and branched endovascular aneurysm repair branch occlusion.
Methods: Patients undergoing 4-vessel fenestrated and branched endovascular aneurysm repair for Extent II to IV thoracoabdominal aortic aneurysms were retrospectively reviewed. Branches that occluded without identifiable kinking or stenosis on computed tomography were included, along with an equal cohort of anatomy-matched patent controls. Patient-specific pulsatile rigid-wall simulations were performed using SimVascular with individualized geometries and boundary conditions. Abnormal time-averaged …
Reinforced Scan: A Reinforcement Learning Enabled Optimal Laser Scan Path Planning In Laser Powder Bed Fusion Additive Manufacturing, Chaoran Dou, Jihoon Chung, Raghav Gnanasambandam, Yuhao Wu, Jianzhi Li, Zhenyu James Kong
Reinforced Scan: A Reinforcement Learning Enabled Optimal Laser Scan Path Planning In Laser Powder Bed Fusion Additive Manufacturing, Chaoran Dou, Jihoon Chung, Raghav Gnanasambandam, Yuhao Wu, Jianzhi Li, Zhenyu James Kong
Manufacturing & Industrial Engineering Faculty Publications
Additive Manufacturing is an innovative technology that fabricates parts layer by layer. However, in Laser Powder Bed Fusion (LPBF), printed metal parts often exhibit residual stresses, deformations, and other defects due to non-uniform temperature distribution during the printing process. To mitigate these issues, an optimized scan sequence within each layer can improve thermal uniformity. Traditional optimization methods, which rely on domain knowledge and employ trial-and-error or heuristic approaches, often fail to achieve optimal solutions due to the complex nature of the problem. One major challenge in improving scan strategies lies in the vast search space required to optimize the scan …
Spectroscopic Investigations On Polyvinylidene Fluoride Nanofibers, Parinaz Amaniabdolmalaki, Jui Vitthal Kharade, Alexandro Trevino, Lydia Morales, Karen Lozano, Victoria Padilla, Karen S. Martirosyan, Horacio Vasquez, Mircea Chipara
Spectroscopic Investigations On Polyvinylidene Fluoride Nanofibers, Parinaz Amaniabdolmalaki, Jui Vitthal Kharade, Alexandro Trevino, Lydia Morales, Karen Lozano, Victoria Padilla, Karen S. Martirosyan, Horacio Vasquez, Mircea Chipara
Physics & Astronomy Faculty Publications
The production of polyvinylidene fluoride nanofibers by force-spinning from polymer solutions was confirmed by electron microscopy. The structural and phase characteristics of the resulting nanofiber mats were examined using Fourier Transform Infrared Spectroscopy in Attenuated Total Reflectance mode, Raman spectroscopy, and X-ray Diffraction. Results from all these techniques consistently indicated that both the powder and the mats of polyvinylidene fluoride predominantly contain the α phase, with a small admixture of the β phase. Within experimental errors, no other phases were noticed both in the powder and in the as-obtained mats. The ratios of the areas of the Raman lines at …
Capturing Sclera Anisotropy Using Direct Collagen Fiber Models: Linking Microstructure To Macroscopic Mechanical Properties, Fengting Ji, Xuehuan He, Frederick Sebastian, Mohammad R. Islam, Hannah Schilpp, Bingrui Wang, Yi Hua, Rouzbeh Amini, Ian A. Sigal
Capturing Sclera Anisotropy Using Direct Collagen Fiber Models: Linking Microstructure To Macroscopic Mechanical Properties, Fengting Ji, Xuehuan He, Frederick Sebastian, Mohammad R. Islam, Hannah Schilpp, Bingrui Wang, Yi Hua, Rouzbeh Amini, Ian A. Sigal
Mechanical Engineering Faculty Publications
Collagen fibers are essential to the mechanical behavior of soft tissues, including sclera. Conventional models often represent these fibers statistically, potentially missing crucial aspects of their role in tissue behavior. In this study, we expand on a direct fiber modeling approach that we recently presented based on explicitly representing the sclera long, interwoven fiber bundles. Specifically, our goal was to capture specimen-specific 3D fiber architecture and anisotropic mechanics of four ovine sclera samples (superior from Eye-1, temporal and superior from Eye-2, and temporal from Eye-3), each tested under five conditions: equi-biaxial (1:1) and four non-equi-biaxial (1:0.75, 0.75:1, 1:0.5, and 0.5:1). …
Rheology-Guided Spinnability In Emulsion Forcespinning Of Water-In-Oil Nanofibers: Influence Of Surfactants And Internal Phase Concentration, Saptasree Bose, Alexandra Salinas, Evelyn Torres, Jose Ramirez, Elizabeth Gamez, Michelle A. Calabrese, Karen Lozano, Victoria Padilla
Rheology-Guided Spinnability In Emulsion Forcespinning Of Water-In-Oil Nanofibers: Influence Of Surfactants And Internal Phase Concentration, Saptasree Bose, Alexandra Salinas, Evelyn Torres, Jose Ramirez, Elizabeth Gamez, Michelle A. Calabrese, Karen Lozano, Victoria Padilla
Mechanical Engineering Faculty Publications
This study explores the emulsion Forcespinning (FS) approach for fabricating nanofibers with a hydrophilic phase encapsulated within a hydrophobic polymer matrix. Key factors influencing fiber production and morphology, including the concentration of the internal water phase and the presence of ionic and nonionic surfactants, were systematically investigated. Additionally, the centrifugal spinnability of the emulsions was assessed using environmentally controlled dripping-onto-substrate (DoS) rheometry, correlating the observed extensional flow behavior and emulsion extensibility with fiber spinnability. The nanofibers were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. These findings offer critical …
Direct Ink Writing Of Shear Exfoliated Two-Dimensional Nanomaterial- Elastomeric Multifunctional Nanocomposite, Md Abdur Rahman Bin Abdus Salam, Asif Hasan Ridoy, A K M Abirul Haque, Muhammad Shahbaz Rafique, Md Arafat Hossain, Md Shahriar Forhad, Matthew G. Boebinger, Farid Ahmed, Karen Lozano, Ali Ashraf
Direct Ink Writing Of Shear Exfoliated Two-Dimensional Nanomaterial- Elastomeric Multifunctional Nanocomposite, Md Abdur Rahman Bin Abdus Salam, Asif Hasan Ridoy, A K M Abirul Haque, Muhammad Shahbaz Rafique, Md Arafat Hossain, Md Shahriar Forhad, Matthew G. Boebinger, Farid Ahmed, Karen Lozano, Ali Ashraf
Manufacturing & Industrial Engineering Faculty Publications
Direct ink writing (DIW) of polymer nanocomposites with high loadings of two-dimensional (2D) nanofillers (graphene and hexagonal boron nitride (hBN)) is challenging because of potential clogging, use of hazardous solvents, and agglomeration. Here, in this work, a shear exfoliation and sieving method to prepare DIW ink with high loading of nanofillers produced from low-cost bulk layered materials such as graphite and bulk hBN powder for successful DIW printing without the use of any solvents, binders, or plasticizers. The single-step exfoliation technique resulted in a composite with substantial layer reduction along the c-axis, as confirmed by SEM, TEM, XRD, and Raman …
Effect Of Graphene Oxide On The Upconversion Photoluminescence Behavior Of Er/Yb Co-Doped Pvdf-Go Composite Nanofibers, Saptasree Bose, Jack Ryan Summers, Bhupendra B. Srivastava, Karen Lozano, Victoria Padilla-Gainza
Effect Of Graphene Oxide On The Upconversion Photoluminescence Behavior Of Er/Yb Co-Doped Pvdf-Go Composite Nanofibers, Saptasree Bose, Jack Ryan Summers, Bhupendra B. Srivastava, Karen Lozano, Victoria Padilla-Gainza
Mechanical Engineering Faculty Publications
Upconversion photoluminescence (UCPL) materials, particularly rare-earth (RE) doped nanoparticles, have garnered significant attention due to their ability to convert near-infrared (NIR) excitation into visible emission, offering benefits such as high photostability, long lifetimes, low autofluorescence, and deep tissue penetration. Among various platforms, polymer-based one-dimensional (1D) nanofibers with in-situ lanthanide doping remain relatively unexplored, despite their superior mechanical flexibility, processability, and potential for improved luminescence performance. In this study, we report the fabrication and UCPL quenching behavior of Er3+/Yb3+ co-doped polyvinylidene difluoride (PVDF) nanofibers incorporated with graphene oxide (GO), synthesized for the first time using the scalable Forcespinning® technique. PVDF, a …
Boundary-Layer Mechanisms In Flow Over Triangular Porous-Textured Flat Plates: A Computational Fluid Dynamics Study, Luis Angel Alvarez
Boundary-Layer Mechanisms In Flow Over Triangular Porous-Textured Flat Plates: A Computational Fluid Dynamics Study, Luis Angel Alvarez
Theses and Dissertations
Growing demand for energy-efficient vehicles drives research into flow control strategies that mitigate aerodynamic drag. Active devices such as morphing flaps or plasma actuators offer real-time authority but require external power. Passive concepts, including riblets, tubercles, porous coatings, and miniature vortex generators, reshape the boundary layer without additional energy input. We propose an integrated passive solution called Triangular Porous Texturing (TPT). TPT combines the two mechanisms: a periodic array of triangular prisms that generate controlled streamwise vortices, and an embedded porous matrix that locally adjusts pressure gradients near the wall. Acting synergistically, these features attenuate near-wall turbulence, redistribute momentum, and …
Development And Testing Of A Prototype Erbium-Doped Lithium Tantalate Based Sensor For Infrastructure Crack Detection And Measurement, Alejandro Barrera
Development And Testing Of A Prototype Erbium-Doped Lithium Tantalate Based Sensor For Infrastructure Crack Detection And Measurement, Alejandro Barrera
Theses and Dissertations
Ensuring the safety and longevity of infrastructure is crucial to safeguarding communities and preserving economic stability. In this study, the development of a novel sensor for detecting and characterizing cracks in infrastructure, particularly suited for deployment on Unmanned Aerial Vehicles (UAVs), is presented. The device utilizes a laser (operating at 980 nm) for excitation of erbium-doped lithium tantalate nanoparticles that emit 1550 nm wavelength, which stimulates a photodiode for data collection. The data was utilized to collect, process, and reconstruct topological information. The synthesized lithium tantalate nanoparticle samples vary in erbium doping percentages of 0.5%, 3%, and 10%. Experimental evaluation …
Feature Extraction From Railroad Bearing Onboard Vibration Sensors Using Machine Learning Models, Diego Cantu
Feature Extraction From Railroad Bearing Onboard Vibration Sensors Using Machine Learning Models, Diego Cantu
Theses and Dissertations
The University Transportation Center for Railway Safety (UTCRS) has developed an algorithm capable of identifying defective railroad bearings, determining damaged component(s) within, and quantifying severity of the defects. The defect-detection algorithm requires the operating speed as an input, which is not readily available in field operation of onboard sensors. Therefore, onboard sensors deployed in rail revenue service must rely on Global Positioning Systems (GPS) to obtain speed, which can be power-intensive and susceptible to signal interference. This study covers the development of a vibration-based model that extracts operating speed from wireless sensor data to enable fully autonomous onboard diagnostics. Signal …
When Textures Trim Drag: Micro-Structures For Adaptive Drag Reduction And Flow Authority, Miguel Angel Olvera
When Textures Trim Drag: Micro-Structures For Adaptive Drag Reduction And Flow Authority, Miguel Angel Olvera
Theses and Dissertations
Turbulent boundary layers are a major source of drag and performance loss. This thesis investigates Triangular Porous Texturing (TPT), apex-forward microstructures with optional bleed channels, as a passive concept for simultaneously reducing skin friction and strengthening boundary layer momentum near separation. Low-speed wind tunnel tests are conducted over tripped turbulent boundary layers on flat plates with three surfaces: a smooth baseline, a solid-crest TPT array isolating the knife-edge “slip-cut” effect, and a porous-bleed TPT array whose paired micro-channels vent a small fraction of the free stream. Time-resolved PIV provides wall-normal velocity fields; skin friction is inferred from near-wall shear, and …
Wearable Triboelectric Nanogenerators Based Sensors For Human Cardiovascular Monitoring: Progress And Perspectives, Mashrufa Akther, Andrea K. Quezada, Md. Arafat Hossain, Julia I. Salas, Md. Mahmud Alam, Mohammed Jasim Uddin
Wearable Triboelectric Nanogenerators Based Sensors For Human Cardiovascular Monitoring: Progress And Perspectives, Mashrufa Akther, Andrea K. Quezada, Md. Arafat Hossain, Julia I. Salas, Md. Mahmud Alam, Mohammed Jasim Uddin
Mechanical Engineering Faculty Publications
Cardiovascular conditions remain the leading cause of death worldwide, driving a critical need for non-invasive, continuous, and dependable health monitoring results. Triboelectric nanogenerators have emerged as a groundbreaking technology enabling self-powered wearable sensors that convert natural biomechanical energy, such as heartbeat, pulse wave, and body motion, into electrical signals. The paper reviews the recent progress and development in TENG-based wearable sensors for cardiovascular monitoring, with a focus on monitoring particular and clinical healthcare. The working principles, advanced materials, structural designs, and integration with wireless data transmission, machine literacy, and bio-signal processing technologies are explored in this article. Operations, including heart …
Performance Assessment Of Reconditioned Freight Rail Bearings Using Eddy Current Array For Enhanced Nondestructive Inspection, Eduardo Miranda
Performance Assessment Of Reconditioned Freight Rail Bearings Using Eddy Current Array For Enhanced Nondestructive Inspection, Eduardo Miranda
Theses and Dissertations
In North America, freight bearings removed from service must undergo a reconditioning process in accordance with Association of American Railroads recommended guidelines before reuse, with approximately 80% having been reconditioned at least once. This process includes bearing inspection, where repairable defects may be refurbished and returned to service with an extended performance range of 50,000 to 250,000 miles. Motivated by this extensive range in performance, researchers at the University Transportation Center for Railway Safety, in collaboration with MxV Rail, utilized a nondestructive evaluation method to enhance the reconditioning inspection process. An Eddy Current Array (ECA) was applied to bearing cup …
Intelligent Real-Time Flotation Froth Stability Monitoring Using Embedded Computer Vision: Lead (Pb) Processing Case Study, Ahmed Bendaouia, Taha Ismaili, Ismail Najib, Oussama Hasidi, Intissar Benzakour, Jianzhi Li, El Hassan Abdelwahed
Intelligent Real-Time Flotation Froth Stability Monitoring Using Embedded Computer Vision: Lead (Pb) Processing Case Study, Ahmed Bendaouia, Taha Ismaili, Ismail Najib, Oussama Hasidi, Intissar Benzakour, Jianzhi Li, El Hassan Abdelwahed
Manufacturing & Industrial Engineering Faculty Publications
Froth stability in flotation refers to the ability of the froth layer to remain intact and avoid collapsing during the flotation process. A stable froth layer is crucial to maximizing mineral recovery and ensuring the efficient operation of flotation cells. Several factors influence the stability of the froth, including the depth of the froth, the crowding, the size of the bubbles, and the rate of movement of the froth. In this study, our main objective is to analyze and evaluate froth stability in real time, since it plays a critical role in process optimization for flotation-based mineral processing. We propose …