Digital Commons Network^™

Quantitative Characterization Of Complex Systems—An Information Theoretic Approach, Aditya Akundi, Eric Smith

Manufacturing & Industrial Engineering Faculty Publications and Presentations

A significant increase in System-of-Systems (SoS) is currently observed in the social and technical domains. As a result of the increasing number of constituent system components, Systems of Systems are becoming larger and more complex. Recent research efforts have highlighted the importance of identifying innovative statistical and theoretical approaches for analyzing complex systems to better understand how they work. This paper portrays the use of an agnostic twostage examination structure for complex systems aimed towards developing an information theorybased approach to analyze complex technical and socio-technical systems. Towards the goal of characterizing system complexity with information entropy, work was carried …

Developing A Prototype Energy Harvesting Device For Powering Wireless Onboard Condition Monitoring Sensor Modules For Railway Service, Martin Amaro Jr.

Theses and Dissertations

An energy harvesting system is being developed to power a wireless bearing health monitoring device. In contrast to other monitoring systems, this wireless monitoring device is a low-powered onboard solution. Powered by a 3.7-Volt lithium-ion battery, the device can continuously function for several months on a single charge. By implementing an energy harvesting system, the life of the battery can be increased reducing the overall maintenance, electronic waste, and time needed to replace the batteries. The harvesting system uses thermoelectric generators to convert the heat generated in the bearings into electricity. The system is composed of aluminum heat sinks, a …

Synthesis And Characterization Of Copper Oxide Nanofibers, Shishir Barai

Theses and Dissertations

The aim of this study was to develop polymer-derived Copper (II) Oxide (CuO) nanofibers through centrifugal spinning technique and subsequent calcining. To obtain the force spun pre-ceramic copper acetate nanofibers, 15% wt, 25% wt, 35% wt, 50% wt% copper acetate (active material) and poly (vinyl) alcohol ( PVA) solutions was prepared with deionized water (DI) as solvent and spun at 7500 rpm in a FibeRio Cyclone. Thermogravimetric analysis (TGA) was implemented to determine the thermal degradation behavior of the pre-ceramic nanofibers. These nanofibers were then calcined at three different temperatures (500, 600 and 700°C) to produce CuO nanofibers. The microstructure, …

Assessing The Effectiveness And Efficacy Of Wireless Onboard Condition Monitoring Modules In Identifying Defects In Railroad Rolling Stock, Lee R. Cantu

Theses and Dissertations

Many industries have begun shifting into the Internet of Things (IoT) in the 21st century. To help ease this transition for the rail industry, The University Transportation Center for Railway Safety (UTCRS) has partnered with Hum Industrial Technology, Inc. (HUM) to help complete the development of a Wireless Onboard Condition Monitoring system named the ‘Boomerang™’. This product allows customers to schedule proactive maintenance on their railcars to replace defective wheels and/or bearings, saving them time, money and potentially preventing costly catastrophic derailments. The UTCRS research team has established thresholds to determine defective bearings utilizing thermal and mechanical sensors.

The effectiveness …

Lubrication Performance Of Vegetable Oils Modified With Halloysite Clay Nanotubes (Hnt) As Lubricant Additives, Md Abu Sayeed Biswas

Theses and Dissertations

Vegetable oil-based nano-lubricants are a great alternative to petroleum-based lubricants because of their less adverse impact on the environment. This work evaluates the tribological performance of sunflower, corn, and peanut oils modified with halloysite clay nanotubes (Al2Si2O2(OH)2nH2O) as lubricant additives at different concentrations. To analyze the tribological performance of the nano-lubricants, a block-on-ring tribometer was used following the ASTM G-077-17 standard procedure. Characterization of HNT was carried out by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA). The effect of the HNT on the lubrication performance of the newly developed vegetable oil-based nano-lubricants was evaluated, and the …

Synthesize And Characterization Of Aluminum- Tungsten Carbide Nanocomposite, Shuvendu Das

Theses and Dissertations

This research focuses on developing metal matrix composite reinforced by polymer-derived ceramic fibers. The force-spun AMT nanofibers were heat treated into tungsten carbide and then mixed with aluminum powder using cold pressing and sintering to produce the composites. The basic mechanical properties of this composite are investigated by density measurement, hardness and compression testing. SEM, EDS and XRD were used to test the morphology of tungsten carbide fibers. EDS identified a near-perfect W-C ratio in tungsten carbide fibers 1000 °C. Tungsten Carbide fibers were crushed using ball milling technique. Tungsten carbide nanofibers powder had a variety of particle size. Results …

Molecular Dynamics Study Of Atomic Diffusion In Cantor High Entropy Alloy In The Selective Laser Melting Process, Mathew Z. Farias

Theses and Dissertations

High entropy alloys (HEAs) are compositionally complex alloys that are comprised of 5 or more principle elements at near equimolar concentrations. The Selective Laser Melting (SLM) method generally melts pure elemental powders or prefabricated alloy powders, this process allows for the production of heterogeneous structures that would be difficult to create through more conventional means. In-situ alloying in SLM, or Laser Additive Alloying (LAA), using pure elemental powders is a promising means of producing what would otherwise be costly and difficult to fabricate products with less defects using prefabricated powders, therefore this new approach could enable the ability to …

Synthesis And Characterization Of Centrifugally Spun Molybdenum-Based Nanomaterials For Lithium-Ion Batteries, Ramiro Gonzalez Jr.

Theses and Dissertations

The work presented in this thesis focuses on the processing and development of transition metal compound composite fibers as anode materials for rechargeable lithium-ion batteries (LIBs). Among the transition metal compounds, molybdenum compounds have risen as promising candidates of advanced electrode materials, in view of their natural abundance, virtuous mechanical/thermal stability, rich chemistry, high theoretical specific capacity, and multiple oxidation states of Mo. The current work reports synthesize MoO2/C and MoO3/C composite fibers drawn from centrifugal spun ammonium molybdate/PAN precursor fibers, followed by a thermal treatment stabilizing in air and calcination under argon atmosphere. The weight ratios of (MoOx, 2 …

Development Of A Compact Core Flooding Apparatus For Matrix Acidizing Applications, Antonio Hernandez Zuniga

Theses and Dissertations

Matrix Acidizing is defined as a well stimulation technique in which the acid is injected into the formation with the purpose of dissolving the minerals present and thus enhancing the permeability of the formation and facilitating the extraction of oil and/or gas from the formation. The primary goal of acid diversion is the creation of wormholes and ramification paths that allow the fluid to flow from the higher to the lower permeability zones of the limestones, sandstones or carbonate reservoirs. Naturally, as the injected acid will follow vugs, fractures and pores, HCl is used because of its quick reaction and …

Selective Laser Melting Of Titanium Diboride: A Study Of The Energy Density Effects, Lazaro Lopez Mendez

Theses and Dissertations

Natural titanium diboride (TiB2) has been reported the 5th hardest material on earth. Due to its superior properties, such as high density, high elastic modulus, and high compressive strength, TiB2 becomes one of the most suitable ceramic reinforcements for applications with severe friction and heavy loading conditions. This study is intended to produce TiB2 using 3D additive manufacture (AM) technology, and then to understand the tribological property of the AM fabricated TiB2 specimens. In this study, a laser additive alloying (LAA) process was developed based on a Renishaw AM laser system. One mm thick samples were prepared using the LAA …

Development Of Vegetable Oil-Based Nano-Lubricants Using Montmorillonite Clay (Mmt) Nanoparticles As Lubricant Additives, Md Mashfiqur Rahman

Theses and Dissertations

Because of the environmental impact and price volatility, there has been a growing concern on the use of petroleum-based lubricants. This issue has stimulated research into the development of biodegradable lubricants like vegetable oils. In this study, the tribological and rheological behavior of sunflower, peanut, and corn oils modified with Montmorillonite nanoclay (MMT) as lubricant additives were evaluated at various concentrations. A custom-made block on ring tribotester was used to evaluate the wear and friction characteristics of the nano-lubricants, following the ASTM G-077-05 standard. The effects of concentration and shear rate on shear viscosity were studied using a parallel plate …

High Performance Electromagnetic Interference Shielding From Lightweight-Flexible Polymer Composite Fiber Structures, Fariha Rubaiya

Theses and Dissertations

This study focuses on the development and characterization of fiber-based polymer composite structures with the goal of developing high performance, flexible, lightweight, and cost-effective materials for electromagnetic interference shielding and piezoelectricity. Polyvinylidene fluoride (PVDF) was used as the base fiber mat while polyaniline (PANI), polypyrrole (PPY), polyindole (PIN), polydiacetylene (PDA) and Zn2GeO4 (ZGO) were incorporated via solution mixing and in-situ polymerization. The PVDF fine fiber systems were produced using the Forcespinning® method. Morphology, structure, thermal stability, electrical properties, EMI shielding effectiveness and piezoelectric performance of the fiber mats were analyzed. The composite system containing 1.25 wt. % of ZGO-PVDF displayed …

Force And Torque Model Sensitivity And Coarse Graining For Bedload-Dominated Sediment Transport, Liheng Guan, Jorge Salinas, ‪Nadim Zgheib, S. Balachandar

Mechanical Engineering Faculty Publications and Presentations

We present results from Euler–Lagrange simulations of turbulent flow over an erodible monodisperse bed of particles at a shear Reynolds number of R e τ = 180 . The Galileo number G a and the ratio of Shields to the critical Shields number Θ / θ c r were varied in the range 11.4 to 29.8 and 1.32 to 5.98, respectively. Two drag force models were investigated along with the influence of lift, particle rotation, and tangential collision forces for each model. Both models give similar results as far as mean particle flux and Shields stress are concerned, however we …

Drug-Based Therapeutic Strategies For Covid-19-Infected Patients And Their Challenges, Khatereh Zarkesh, Elaheh Entezar-Almahdi, Parisa Ghasemiyeh, Mohsen Akbarian, Marzieh Bahmani, Shahrzad Roudaki, Rahil Fazlinejad, Soliman Mohammadi-Samani, Negar Firouzabadi, Majid Hosseini, Fatemeh Farjadian

Manufacturing & Industrial Engineering Faculty Publications and Presentations

Emerging epidemic-prone diseases have introduced numerous health and economic challenges in recent years. Given current knowledge of COVID-19, herd immunity through vaccines alone is unlikely. In addition, vaccination of the global population is an ongoing challenge. Besides, the questions regarding the prevalence and the timing of immunization are still under investigation. Therefore, medical treatment remains essential in the management of COVID-19. Herein, recent advances from beginning observations of COVID-19 outbreak to an understanding of the essential factors contributing to the spread and transmission of COVID-19 and its treatment are reviewed. Furthermore, an in-depth discussion on the epidemiological aspects, clinical symptoms …

Subharmonic Resonance Of One Fourth Order Of Electrostatically Actuated Mems Circular Plates: Amplitude-Frequency Response, Dumitru Caruntu, Julio Beatriz, Miguel Martinez

Mechanical Engineering Faculty Publications and Presentations

This work deals with the amplitude-frequency response subharmonic resonance of 1/4 order of electrostatically actuated circular plates. The method of multiple scales is used to model the hard excitations and to predict the response. This work predicts that the steady state solutions are zero amplitude solutions, and non-zero amplitude solutions which consist of stable and unstable branches. The effects of parameters such as voltage and damping on the response are predicted. As the voltage increases, the non-zero amplitude solutions are shifted to lower frequencies. As the damping increases, the non-zero steady-state amplitudes are shifted to higher amplitudes, so larger initial …

A Framework Of Dynamic Data Driven Digital Twin For Complex Engineering Products: The Example Of Aircraft Engine Health Management, Zhenhua Wu, Jianzhi Li

Manufacturing & Industrial Engineering Faculty Publications and Presentations

Digital twin is a vital enabling technology for smart manufacturing in the era of Industry 4.0. Digital twin effectively replicates its physical asset enabling easy visualization, smart decision-making and cognitive capability in the system. In this paper, a framework of dynamic data driven digital twin for complex engineering products was proposed. To illustrate the proposed framework, an example of health management on aircraft engines was studied. This framework models the digital twin by extracting information from the various sensors and Industry Internet of Things (IIoT) monitoring the remaining useful life (RUL) of an engine in both cyber and physical domains. …

Forcespun Polyvinylpyrrolidone/Copper And Polyethylene Oxide/Copper Composite Fibers And Their Use As Antibacterial Agents, Md Toukir Hasan, Ramiro Gonzalez, Ari Alexis Munoz, Luis Materon, Jason Parsons, Mataz Alcoutlabi

Mechanical Engineering Faculty Publications and Presentations

Copper nanoparticles (CuNPs) embedded in polyvinylpyrrolidone (PVP) and polyethylene oxide (PEO) fiber-matrices were prepared through centrifugal spinning of PVP/ethanol and PEO/aqueous solutions, respectively. The prime focus of the current study is to investigate the antibacterial activity of composite fibers against Escherichia coli (E. coli) and Bacillus cereus (B. cereus) bacteria. During the fiber formation, the centrifugal spinning parameters such as spinneret rotational speed, spinneret to collector distance, and relative humidity were carefully chosen to obtain long and continuous fibers. The structural and morphological analyses of both composite fibers were investigated using scanning electron microscopy, X-ray diffraction, …

Optimal Tracking In Switched Systems With Free Final Time And Fixed Mode Sequence Using Approximate Dynamic Programming, Tohid Sardarmehni, Xingyong Song

Mechanical Engineering Faculty Publications and Presentations

Optimal tracking in switched systems with fixed mode sequence and free final time is studied in this article. In the optimal control problem formulation, the switching times and the final time are treated as parameters. For solving the optimal control problem, approximate dynamic programming (ADP) is used. The ADP solution uses an inner loop to converge to the optimal policy at each time step. In order to decrease the computational burden of the solution, a new method is introduced, which uses evolving suboptimal policies (not the optimal policies), to learn the optimal solution. The effectiveness of the proposed solutions is …

Centrifugal Spinning And Characterization Of Co3o4 Coated Carbon Fibers, J. Ayala, D. Ramirez, Elizabeth M. Fletes, Helia Magali Morales, Jason Parsons, Mataz Alcoutlabi

Mechanical Engineering Faculty Publications and Presentations

Centrifugally spun polyacrylonitrile (PAN) microfibers surface-coated with Co3O4 nanoparticles (NPs) were prepared as precursors to produce coated Co3O4 carbon-composite fibers. The Co3O4/C composite fibers were obtained through a staged heating process during which the Co3O4PAN precursor fibers were stabilized over four hours at 200 °C, and subsequently the stabilized fibers were carbonized for six hours at 600 °C. The synthesis process presented in this work provides an effective strategy for the fabrication of surface coated-fiber materials, including composite fibers with good structure and morphology. The characterization of the Co3O4/C composite fibers was performed using SEM, EDS, XPS, XRD …

Numerical Study Of Fully Coupled Fluid-Structure Interaction Of Stented Ureter By Varying The Stent Side-Holes, Erick Martinez, Ben Xu, Jianzhi Li, Yingchen Yang

Mechanical Engineering Faculty Publications and Presentations

Ureteral stents are a measure used for many medical issues involving urology, such as kidney stones or kidney transplants. The purpose of applying stents is to help relieve the urine flow while the ureter is either blocked or trying to close itself, which creates blockages. These ureteral stents, while necessary, cause pain and discomfort to patients due to them being a solid that moves around inside the patients’ body. The ureter normally moves urine to the bladder through peristaltic forces. Due to the ureter being a hyperelastic material, these peristaltic forces cause the ureter to deform easily, making it necessary …

Piezoelectric Properties Of Pvdf-Zn2geo4 Fine Fiber Mats, Fariha Rubaiya, Swati Mohan, Bhupendra B. Srivastava, Horacio Vasquez, Karen Lozano

Mechanical Engineering Faculty Publications and Presentations

The current paper presents the development and characterization of polyvinylidene fluoride (PVDF)-Zn₂GeO₄ (ZGO) fine fiber mats. ZGO nanorods (NRs) were synthesized using a hydrothermal method and incorporated in a PVDF solution to produce fine fiber mats. The fiber mats were prepared by varying the concentration of ZGO NRs (1.25–10 wt %) using the Forcespinning^® method. The developed mats showed long, continuous, and homogeneous fibers, with average fiber diameters varying from 0.7 to 1 µm, depending on the ZGO concentration. X-ray diffraction spectra depicted a positive correlation among concentration of ZGO NRs and strengthening of the beta …

Investigation Of Different Hatch Strategies On High Entropy Alloy Fabrication By Selective Laser Melting, Joni Chandra Dhar

Theses and Dissertations

This study investigated the synthesis of CuCrFeNiTiAl high entropy alloy (HEA) from pure elements using selective laser melting (SLM). The objectives are to validate the feasibility of the HEA fabrication from elemental powder materials, and to examine the effect of various hatch strategies and energy densities on the microstructures and other materials properties. 3D samples of CuCrFeNiTiAl alloy were fabricated under different energy densities and with different scan vector lengths. The as-built samples were characterized by X-ray diffraction (XRD), and the microstructures were observed using scanning electron microscopy (SEM). The XRD results showed that face centered cubic, and body centered …

Micro Scalable Graphene Oxide Productions Using Controlled Parameters In Bench Reactor, Carolina S. Andrade, Anna Paula Godoy, Marcos Antônio Gimenes Benega, Ricardo J. E. Andrade, Rafael Cardoso Andrade, Wellington Marcos Silva, Josué Marciano De Oliveira Cremonezzi, Waldemar Augusto De Almeida Macedo, Hélio Ribeiro, Jaime Taha-Tijerina

Manufacturing & Industrial Engineering Faculty Publications and Presentations

The detailed study of graphene oxide (GO) synthesis by changing the graphite/oxidizing reagents mass ratios (mG/mROxi), provided GO nanosheets production with good yield, structural quality, and process savings. Three initial samples containing different amounts of graphite (3.0 g, 4.5 g, and 6.0 g) were produced using a bench reactor under strictly controlled conditions to guarantee the process reproducibility. The produced samples were analyzed by Raman spectroscopy, atomic force microscopy (AFM), x-ray diffraction (XDR), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FTIR) and thermogravimetry (TGA) techniques. The results showed that the major GO product comprised of nanosheets containing between 1–5 layers, …

Effect Of Obesity On Knee Joint During Walking And Squatting, Simon Vasquez Iii

Theses and Dissertations

This paper analyzes the effect of obesity on the knee joints during squats. This was performed on 2 different subjects by having each squat 30 times at their decided comfortable depth to display some fatigue and effects on the knee joints. Using the VICON NEXUS and AMTI force plates equipment at The University of Texas at Rio Grande Valley Biomechanics Lab, the center of pressure, knee flexion angles, velocity, and ground reaction forces were calculated. The subjects performed the exercises with and without additional weight using a body vest and kettlebell. The ground reaction forces showed a significant increase in …

Effect Of Deposition Conditions On Properties Of Molybdenum Back Electrode For Cu(In,Ga)Se2 Solar Cell And Cu(In,Ga)Se2 Performance Analysis Through Numerical Simulation, Meah Imtiaz Zulkarnain

Theses and Dissertations

In the first part of this research, the effect of the deposition conditions on properties of molybdenum thin-film were investigated to achieve desired characteristics for its application as the back electrode of Cu(In,Ga)Se2 solar cell. DC and RF magnetron sputtering modes were employed and two sputtering parameters namely, working pressure and sputtering power, were varied to determine the sputtering mode and the sputtering conditions best suited for Mo thin-films having required properties. Sputtered Mo samples were characterized to determine their structural and mechanical properties such as preferred growth orientation, crystallinity, grain size, dislocation density, adhesion, and micro strain, and electrical …

Using Single-Molecule Dna Flow-Stretching Experiments To See The Effects Of Temperature And Viscosity, Fatema Tuz Zohra

Theses and Dissertations

Deoxyribonucleic acid (DNA) is a highly charged long and semi-flexible polymer of which length is much longer than cell dimensions at least by 1,000-folds. A long linear DNA turns into a crumpled structure to fit into a tiny cell volume by the process known as DNA compaction. In nature, DNA fits into the volume of the cell using DNA compaction by packaging genome material. Various types of protein are involved in DNA compaction. To experiment with various proteins as DNA compaction agents, DNA needs to be stretched out. In our thesis, the effect of temperature and buffer viscosity on DNA …

Effect Of Obesity On Walking To Running And Running To Walking Transitions, Salvador Baruch Alcorta Bautista

Theses and Dissertations

This work investigates human Walking to Running transition (WRT) and Running to Walking transition (RWT). The focus is to be able to identify the correct WRT and RWT phase jumps. This investigation uses experimental data from the VICON Motion Analysis System (MAS) and of the treadmill WRT and RWT trials. The musculoskeletal model consists of pelvis, femur, tibia, and foot. This investigation uses as reference the work reported in the literature by Diedricj and Warren.. For the calculations in this investigation Excel and Matlab are used to filter the data and calculate the relative phase jumps. This work reports the …

Laser-Induced Forward Transfer (Lift) Based Bioprinting Of The Collagen I With Retina Photoreceptor Cells, Md Shakil Arman

Theses and Dissertations

This thesis focuses on the 3D bioprinting of retina cone cells using the laser-induced forward transfer (LIFT) technique. Bioprinting has a great potential to mimic and regenerate the human organoid system, and the LIFT technique has emerged as an efficient method for high resolution micropatterning and microfabrication of biomaterials and cells due to its capability of creating precise, controlled microdroplets. In this research, the parameters for an effective femtosecond laser-based LIFT process for 3D bioprinting of collagen biomaterial were studied. Different concentrations of collagen I solutions were tested to find out the right concentration that can be transferred through the …

Force Spun Pvdf And Tpu Nanofiber Based Triboelectric Nanogenerator For Energy Harvesting And Sensor Application, Sk Shamim Hasan Abir

Theses and Dissertations

Flexible and stretchable triboelectric nanogenerator (TENG) is the next generation potential candidate for wearable and portable electronics. In this study, we have demonstrated all nanofiber based TENG for energy harvesting and biomechanical sensing applications. The TENG was prepared by force spun polyvinylidene fluoride (PVDF) and gold (Au) sputtered thermoplastic polyurethane (TPU) nanofiber (NF) layer. The experimental characterization of the PVDF-TPU/Au NF-TENG revealed that surface modification by dispersed gold in TPU fiber membrane resulted the maximum open circuit voltage (254 V) and short circuit current (86 μA) output at 240 bpm (beats per minute) load frequency which was respectively 112% and …

Effect Of Additional Weight On Stability Of Human Squat Exercise, Jose De Jesus Galarza Lozano

Theses and Dissertations

The main focus of the study is to analyze the stability of the squat exercise. The squat is a common exercise that persons do for exercise. The study analyze the time series of the normal component of the ground reaction forces and each coordinate of the center of pressure. Theses time series are used to estimate the Lyapunov Exponents using Rosenstein method. MATLAB from Mathworks is used to calculate the graphs and program the methods. We compare this result with the literature and previous experiments. This work gives more information relating the safety of the squat exercise when …