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Articles 241 - 270 of 657
Full-Text Articles in Mechanical Engineering
Predicting The Remaining Service Life Of Railroad Bearings: Leveraging Machine Learning And Onboard Sensor Data, Leonel Villafranca
Predicting The Remaining Service Life Of Railroad Bearings: Leveraging Machine Learning And Onboard Sensor Data, Leonel Villafranca
Theses and Dissertations
By continuously monitoring train bearing health in terms of temperature and vibration levels of bearings tested in a laboratory setting, statistical regression models have been developed to establish relationships between the sensor-acquired bearing health data with several explanatory factors that potentially influence the bearing deterioration. Despite their merits, statistical models fall short of reliable prediction accuracy levels since they entail restrictive assumptions, such as a priori known functional relationship between the response and input variables. A data-driven machine learning algorithm is presented, which can unravel the nonlinear deterioration model purely based on the bearing health data, even when the structure …
Transient Thermal Analysis Of A Railroad Bearing Adapter For Optimal Placement Of Onboard Sensors, Javier E. Arroyo, Constantine Tarawneh, Arturo Fuentes, Roberto A. Garcia, Jose G. Gallegos
Transient Thermal Analysis Of A Railroad Bearing Adapter For Optimal Placement Of Onboard Sensors, Javier E. Arroyo, Constantine Tarawneh, Arturo Fuentes, Roberto A. Garcia, Jose G. Gallegos
Mechanical Engineering Faculty Publications
Bearing temperature serves as an important metric used in identifying defective bearings in the rail industry. Current defect detection systems, such as the Hot Box Detectors (HBDs), are used to measure the temperature of freight car roller bearings. The HBD is a wayside device that utilizes a non-contact infrared sensor to determine the operating temperature of a railroad bearing as it passes over the HBD. Railroads analyze the data collected by HBDs to detect and flag defective bearings. If the operating temperature of a bearing surpasses a predetermined threshold, an emergency stop is initiated, and the bearing is removed from …
Improved Guidelines Of Indoor Airborne Transmission Taking Into Account Departure From The Well-Mixed Assumption, Jorge S. Salinas, K. A. Krishnaprasad, Nadim Zgheib, S. Balachandar
Improved Guidelines Of Indoor Airborne Transmission Taking Into Account Departure From The Well-Mixed Assumption, Jorge S. Salinas, K. A. Krishnaprasad, Nadim Zgheib, S. Balachandar
Mechanical Engineering Faculty Publications
The well-mixed assumption has been widely used in predicting the spread of infectious diseases in indoor spaces. It is to be expected that a perfect well-mixed state will not be achieved in an indoor space at any reasonable level of ventilation. This work evaluates the well-mixed assumption by comparing the theory with results from large eddy simulations. The robustness of the well-mixed theory is established by comparing at four different levels. The comparison also points out systematic departures in pathogen concentration which can be accurately accounted for with an easily implementable correction factor to quantities such as cumulative exposure time. …
Performance Of A Thermoelectric-Based Energy Harvesting Device On A Realistic Railroad Route, Martin Amaro Jr., Constantine Tarawneh, Heinrich D. Foltz, Ruben Aguilera Toro, Curtis Pena
Performance Of A Thermoelectric-Based Energy Harvesting Device On A Realistic Railroad Route, Martin Amaro Jr., Constantine Tarawneh, Heinrich D. Foltz, Ruben Aguilera Toro, Curtis Pena
Mechanical Engineering Faculty Publications
Researchers at the University Transportation Center for Railway Safety (UTCRS) have developed an onboard wireless monitoring device to gauge the health of freight railcar rolling stock. A wireless system will allow for preemptive maintenance to occur, potentially saving millions of dollars in damages and ensuring the safety of passengers and cargo. A prototype energy harvester has been developed that can extend the battery life of the wireless monitoring device. It uses Thermoelectric Generators (TEGs) mounted on the bearing adapter to convert heat generated from the bearings to electricity. Previous results have shown that, under optimal conditions, TEGs have been able …
Conductive Polymer Pad For Use In Freight Railcar Bearing Adapters, Jesse Aguilera, Constantine Tarawneh, Harry Siegel, Robert Jones, Santana Gutierrez
Conductive Polymer Pad For Use In Freight Railcar Bearing Adapters, Jesse Aguilera, Constantine Tarawneh, Harry Siegel, Robert Jones, Santana Gutierrez
Mechanical Engineering Faculty Publications
Many freight railcars rest on polymer adapter pads made of injection-molded Thermoplastic Polyurethane (TPU) polymers which feature two copper studs to provide electrical conductivity through the pad. This design feature allows signal transmission from the track to the onboard systems, including cargo gates and pneumatic actuators. While in service, the polymer pads experience impact and cyclic loading that produce shear, resulting in the abrasive wear and plastic compression of the copper studs which leads to signal interruptions and loss of function requiring the periodic replacement of these polymer pads. This causes increased downtime due to maintenance and reduced reliability in …
Pilot Field Test Of An Onboard Wireless Condition Monitoring System For Railroad Rolling Stock, Marco A. Barrera, Heinrich D. Foltz, Lee R. Cantu, Brent Wilson, Constantine Tarawneh, Byron Porter
Pilot Field Test Of An Onboard Wireless Condition Monitoring System For Railroad Rolling Stock, Marco A. Barrera, Heinrich D. Foltz, Lee R. Cantu, Brent Wilson, Constantine Tarawneh, Byron Porter
Mechanical Engineering Faculty Publications
The “internet of things” has revolutionized the methods in which many industries have optimized performance and component defect detection by providing real-time feedback through the implementation of data processing and wireless communication. Despite these advancements, the railway industry has lingered stagnant in its approach of adopting these advanced prognostic detection systems, and instead relies on discretely (25–40 miles) placed trackside condition monitoring systems, aka wayside. These wayside systems are primarily used to detect abnormal operating conditions in railcar rolling stock components. However, while they have been used for decades to address imminent threats to derailments and/or safety, they have unfortunately …
Multifunctional Hybrid Mos2-Pegylated/Au Nanostructures With Potential Theranostic Applications In Biomedicine, Thiago R. S. Malagrino, Anna Paula Godoy, Juliano M. Barbosa, Abner G. T. Lima, Nei C. O. Sousa, Jairo J. Pedrotti, Pamela S. Garcia, Roberto M. Paniago, Lídia M. Andrade, Jaime Taha-Tijerina
Multifunctional Hybrid Mos2-Pegylated/Au Nanostructures With Potential Theranostic Applications In Biomedicine, Thiago R. S. Malagrino, Anna Paula Godoy, Juliano M. Barbosa, Abner G. T. Lima, Nei C. O. Sousa, Jairo J. Pedrotti, Pamela S. Garcia, Roberto M. Paniago, Lídia M. Andrade, Jaime Taha-Tijerina
Informatics and Engineering Systems Faculty Publications
In this work, flower-like molybdenum disulfide (MoS2) microspheres were produced with polyethylene glycol (PEG) to form MoS2-PEG. Likewise, gold nanoparticles (AuNPs) were added to form MoS2-PEG/Au to investigate its potential application as a theranostic nanomaterial. These nanomaterials were fully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), photoelectron X-ray spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), cyclic voltammetry and impedance spectroscopy. The produced hierarchical MoS2-PEG/Au microstructures showed an average diameter of 400 nm containing distributed gold nanoparticles, with great cellular viability on tumoral and non-tumoral cells. This aspect makes them with multifunctional characteristics with potential application …
Electrically Conductive Bearing Adapter Polymer Pad For Use In Freight Railcar Service Applications, Jesse M. Aguilera
Electrically Conductive Bearing Adapter Polymer Pad For Use In Freight Railcar Service Applications, Jesse M. Aguilera
Theses and Dissertations
Many freight railcars rest on polymer adapter pads made of injection-molded Thermoplastic Polyurethane (TPU) polymers which feature two copper studs to provide electrical conductivity through the adapter pads, which power onboard systems. In service, pads experience impact and cyclic loading, resulting in wear and plastic compression of the copper studs. This leads to signal interruptions and periodic replacement of the polymer pads, which results in downtime due to maintenance and reduced reliability since pad failure is unpredictable. These limitations in the current design are the impetus to create an electrically conductive polymer adapter pad that does not rely on the …
Railcar Wheel Impact Detection Utilizing Vibration-Based Wireless Onboard Condition Monitoring Modules, Marco A. Barrera
Railcar Wheel Impact Detection Utilizing Vibration-Based Wireless Onboard Condition Monitoring Modules, Marco A. Barrera
Theses and Dissertations
The current limitations in established rail transport condition monitoring methods have motivated the UTCRS railway research team at UTRGV to investigate a novel solution that can address these deficiencies through wired, onboard, and vibration-based analytics. Due to the emergence of the Internet of Things (IoT), the research team has now transitioned into developing wireless modules that take advantage of the rapid data processing and wireless communication features these systems possess. This has enabled UTCRS to partner with Hum Industrial Technology, Inc. to assist them in the development of their “Boomerang” wireless condition monitoring system. Designed to revolutionize the way the …
Evaluation Of Accelerated Testing Methods To Predict The Effects Of Chemical Exposure On Mechanical Properties Of Polyester Composites In Municipal Wastewater Service, Roberto A. Garcia
Evaluation Of Accelerated Testing Methods To Predict The Effects Of Chemical Exposure On Mechanical Properties Of Polyester Composites In Municipal Wastewater Service, Roberto A. Garcia
Theses and Dissertations
Composite Access Products (CAP) is a company that is determined to replace traditional steel manhole covers with fiber reinforced polymer alternatives that have similar performance while also introducing several advantages. CAP can achieve this by manufacturing the polymer manhole covers using high-speed, high pressure compressing molding to produce lightweight, long-lasting, corrosive resistant covers. CAP’s composite covers have been approved for use by TXDOT in roadway zones. Despite this, they must now undergo more testing and verification for use in environments with highly corrosive elements such as sewage environments and waste processing plants. In these situations, the polymer manhole covers will …
Machine Learning Based Aerodynamic Shape Optimization, Noe Martinez Jr.
Machine Learning Based Aerodynamic Shape Optimization, Noe Martinez Jr.
Theses and Dissertations
The coefficient of pressure distribution for various 2D airfoil geometries were found using source – vortex panel methods. The data obtained in these simulations was used in multiple machine learning models which would predict the airfoil geometry from a given coefficient of pressure distribution. The neural networks employed were fully connected feedforward networks with Levenberg – Marquardt backpropagation and one model employed Bayesian Regularization. A novel tool for optimizing airfoil shape for a given coefficient of pressure distribution was created which performed well during testing. These models serve as the first step in minimizing the conflict between aerodynamic and stealth …
Self-Diverting Nanofluid In-Situ Gelled Acid For Matrix Acidizing Applications In Carbonate Formations, Javier Alejandro Perez
Self-Diverting Nanofluid In-Situ Gelled Acid For Matrix Acidizing Applications In Carbonate Formations, Javier Alejandro Perez
Theses and Dissertations
The main purpose of this project is to develop a nanofluid system that would help to divert the injected acid from the main flow regime into a relatively lower permeability zone and being able to dissolve the rock significantly. The system is meant to successfully create acidic gel in-situ after injecting the fluid in solution. It is expected that by altering either pH, temperature or amount of reactants, the viscosity of the fluid can be controlled so that the gel can be broken at a desired time.
An Experimentally Validated Finite Element Model Of Thermal Transient Response Of A Railroad Bearing Adapter, Javier E. Arroyo
An Experimentally Validated Finite Element Model Of Thermal Transient Response Of A Railroad Bearing Adapter, Javier E. Arroyo
Theses and Dissertations
Wayside hot box detectors (HBDs) are devices used to determine the health of railcar components such as bearings, axles, and brakes by monitoring the radiated temperature form these components. HBDs have been instrumental in reducing rail derailments in the decade, but the number of non-verified bearing removals has increased significantly. To combat these limitations, researchers have opted to use wireless onboard sensor devices directly mounted on the bearing adapter. The wireless onboard health monitoring system developed by the University Transportation Center for Railway Safety (UTCRS) utilizes temperature and vibration sensors to detect the condition of rolling stock. However, because the …
Cloth-Water Interaction For Air Humidification In Hdh Desalination, Alejandro Corona Martinez
Cloth-Water Interaction For Air Humidification In Hdh Desalination, Alejandro Corona Martinez
Theses and Dissertations
The humidification-dehumidification (HDH) desalination technology is a promising desalination process that has the potential to provide cost-effective and environmentally friendly saltwater desalination, especially when combined with renewable energy sources. The working principle mimics the natural hydrologic cycle, involving the evaporation of seawater into water vapor (humidification) and condensation into freshwater (dehumidification). HDH desalination can be land-based or ocean-based. Some of the advantages of ocean-based systems include removing pretreatment processes, utilization of ocean energy (i.e. thermal and kinetic), and eliminating brine production. This study focuses on the design and experimental testing of a novel humidifier …
Machine Learning Tools In The Predictive Analysis Of Ercot Load Demand Data, Md Riyad Hossain
Machine Learning Tools In The Predictive Analysis Of Ercot Load Demand Data, Md Riyad Hossain
Theses and Dissertations
The electric load industry has seen a significant transformation over the last few decades, culminating in the establishment and implementation of electricity markets. This transition separates electric generation services into a distinct, more competitive sector of the industry, allowing for the introduction of greater unpredictability into the system. Forecasting power system load has developed into a core research area in power and energy demand engineering in order to maintain a constant balance between electricity supply and demand. The purpose of this thesis dissertation is to reduce power system uncertainty by improving forecasting accuracy through the use of sophisticated machine …
Investigation Of A Simultaneaous Direct And Indirect Contact Dehumidifier Using Parallel Strings For Hdh Desalination, Josue Perez Perez
Investigation Of A Simultaneaous Direct And Indirect Contact Dehumidifier Using Parallel Strings For Hdh Desalination, Josue Perez Perez
Theses and Dissertations
Freshwater is a limited and precious resource. Currently, half a billion people in the world face sever water scarcity all year round. Humidification dehumidification (HDH) systems have received special attention among the variety of small-scale desalination technologies due to its potential to create affordable and sustainable seawater desalination, especially when combined with natural power sources such as waves, wind, and solar rays. Improvements in the development of HDH desalination systems have been achieved in recent years. Nonetheless, the improvements that have received most attention focus on solar heaters and humidifiers. Dehumidification systems have often been adapted from air conditioning condensation …
Monitoring Of Tool Wear And Surface Roughness Using Anfis Method During Cnc Turning Of Cfrp Composite, Md Mofakkirul Islam
Monitoring Of Tool Wear And Surface Roughness Using Anfis Method During Cnc Turning Of Cfrp Composite, Md Mofakkirul Islam
Theses and Dissertations
Carbon fiber-reinforced plastic (CFRP) is gaining wide acceptance in areas including sports, aerospace and automobile industry . Because of its superior mechanical qualities and lower weight than metals, it needs effective and efficient machining methods. In this study, the relationship between the cutting parameters (Speed, Feed, Depth of Cut) and response parameters (Vibration, Surface Finish, Cutting Force and Tool Wear) are investigated for CFRP composite. For machining of CFRP, CNC turning operation with coated carbide tool is used. An ANFIS model with two MISO system has been developed to predict the tool wear and surface finish. Speed, feed, depth of …
Quantum Dynamics Effects On Amplitude-Frequency Response Of Superharmonic Resonance Of Second-Order Of Electrostatically Actuated Nems Circular Plates, Dumitru Caruntu, Julio S. Beatriz
Quantum Dynamics Effects On Amplitude-Frequency Response Of Superharmonic Resonance Of Second-Order Of Electrostatically Actuated Nems Circular Plates, Dumitru Caruntu, Julio S. Beatriz
Mechanical Engineering Faculty Publications
This work deals with the effects of Casimir and/or van der Waals forces (quantum dynamics phenomena) on the amplitude-frequency response of the superharmonic resonance of second-order of axisymmetric vibrations of electrostatically actuated nanoelectromechanical systems (NEMS) clamped circular plates. Electrostatic actuation consists of alternating current (AC) voltage of magnitude to produce hardexcitationsandoffrequencynearonefourththenaturalfrequencyoftheclamped circular plate. The intermolecular forces Casimir and van der Waals, damping force, and electrostatic force are the forces acting on the NEMS plate. Six Reduced Order Models (ROMs) with one and up to 6 modes of vibration are used. The ROM with one mode of vibration is solved using …
On The Thermogravimetric Analysis Of Polymers: Polyethylene Oxide Powder And Nanofibers, Oriretan Omosola, Dorina M. Chipara, Mohammed Jasim Uddin, Karen Lozano, Mataz Alcoutlabi, Victoria Padilla-Gainza, Mircea Chipara
On The Thermogravimetric Analysis Of Polymers: Polyethylene Oxide Powder And Nanofibers, Oriretan Omosola, Dorina M. Chipara, Mohammed Jasim Uddin, Karen Lozano, Mataz Alcoutlabi, Victoria Padilla-Gainza, Mircea Chipara
Mechanical Engineering Faculty Publications
Thermogravimetric analysis of polyethylene oxide (powder and nanofibers obtained by force spinning water or chloroform solutions of polyethylene oxide) was studied using different theoretical models such as Friedman and Flynn-Wall-Ozawa. A semiempirical approach for estimating the “sigmoid activation energy” from the thermal degradation was suggested and confirmed by the experimental data on PEO powder and nanofibers' mats. The equation allowed for calculating a “sigmoid activation energy” from a single thermogram using a single heating rate without requiring any model for the actual complex set of chemical reactions involved in the thermal degradation process. For PEO (powder and nanofibers obtained from …
Carbon Nanotori Reinforced Lubricants In Plastic Deformation Processes, Jaime Taha-Tijerina, Juan Manuel Martinez, Daniel Euresti, Patsy Yessenia Arquieta-Guillen
Carbon Nanotori Reinforced Lubricants In Plastic Deformation Processes, Jaime Taha-Tijerina, Juan Manuel Martinez, Daniel Euresti, Patsy Yessenia Arquieta-Guillen
Manufacturing & Industrial Engineering Faculty Publications
This research presents the effects of carbon nanotori structures (CNst) dispersed as reinforcement for metal-working and metal-forming lubricants. Synthetic (SL) and deep drawing (DD) nanolubricants were prepared following a two-step method at 0.01 wt.%, 0.05 wt.%, and 0.10 wt.% filler fractions. Slight increases in viscosity (oz) increased by 16% and 22% at merely 0.01 wt.% CNst reinforcement and up to 73% and 107% at 0.10 wt.% filler fraction for SL and DD nanolubricants, respectively, compared to conventional materials. Additionally, at 0.10 wt.% wear scar evaluations showed a highest benefit of 16% and 24%, for SL and DD nanolubricants, respectively. This …
Model-Assisted Deep Learning Of Rare Extreme Events From Partial Observations, Anna Asch, Ethan Brady, Hugo Gallardo, John Hood, Bryan Chu, Mohammad Farazmanda
Model-Assisted Deep Learning Of Rare Extreme Events From Partial Observations, Anna Asch, Ethan Brady, Hugo Gallardo, John Hood, Bryan Chu, Mohammad Farazmanda
Mechanical Engineering Faculty Publications
To predict rare extreme events using deep neural networks, one encounters the so-called small data problem because even long-term observations often contain few extreme events. Here, we investigate a model-assisted framework where the training data are obtained from numerical simulations, as opposed to observations, with adequate samples from extreme events. However, to ensure the trained networks are applicable in practice, the training is not performed on the full simulation data; instead, we only use a small subset of observable quantities, which can be measured in practice. We investigate the feasibility of this model-assisted framework on three different dynamical systems (Rössler …
Evaluation Of Microstructural And Mechanical Behavior Of Ahss Cp780 Steel Welded By Gmaw-Pulsed And Gmaw-Pulsed-Brazing Processes, Alan Jadir Romero-Orozco, Jaime Taha-Tijerina, Rene De Luna-Alanis, Victor Hugo Lopez-Morelos, Maria Del Carmen Ramirez, Melchor Salazar-Martinez, Francisco Fernando Curiel-Lopez
Evaluation Of Microstructural And Mechanical Behavior Of Ahss Cp780 Steel Welded By Gmaw-Pulsed And Gmaw-Pulsed-Brazing Processes, Alan Jadir Romero-Orozco, Jaime Taha-Tijerina, Rene De Luna-Alanis, Victor Hugo Lopez-Morelos, Maria Del Carmen Ramirez, Melchor Salazar-Martinez, Francisco Fernando Curiel-Lopez
Manufacturing & Industrial Engineering Faculty Publications
Joints of complex phase 780 (CP-780) advanced high strength steel (AHSS) were carried out by using an ER-CuAl-A2 filler metal for the gas metal arc welding pulsed brazing (GMAW-P- brazing) process and the ER-80S-D2 for the GMAW-P process employing two levels of heat input. The phases in the weld bead and HAZ were analyzed, and the evaporation of zinc by means of scanning electron microscopy (SEM) was also monitored. The mechanical properties of the welded joints were evaluated by tension, microhardness and vertical impact tests. It was found that there was greater surface Zn evaporation in the joints welded with …
Innovations In Engineering Education For Fast-Paced Virtual Summer Courses, Eleazar Marquez, Samuel Garcia
Innovations In Engineering Education For Fast-Paced Virtual Summer Courses, Eleazar Marquez, Samuel Garcia
Mechanical Engineering Faculty Publications
In this study, the recently developed CIRE (Communication, Initiation, Reduction, and Extension) pedagogical model was modified to generate an effective framework for a virtual, fast-paced summer engineering course in a private university in Texas. Transitioning to fully online courses in the wake of COVID-19 required rectifying traditional instructional methods to overcome challenges such as the lack of academic resources and established campus practices, while simultaneously ensuring the academic development of students. Thus, a pedagogical framework known as the CIRE model was recently designed and implemented in a Rigid Body Dynamics course, which according to the study, generated favorable results. To …
State Of Industry 5.0—Analysis And Identification Of Current Research Trends, Aditya Akundi, Daniel Euresti, Sergio Luna, Wilma Ankobiah, Amit Lopes, Immanuel Edinbarough
State Of Industry 5.0—Analysis And Identification Of Current Research Trends, Aditya Akundi, Daniel Euresti, Sergio Luna, Wilma Ankobiah, Amit Lopes, Immanuel Edinbarough
Manufacturing & Industrial Engineering Faculty Publications
The term Industry 4.0, coined to be the fourth industrial revolution, refers to a higher level of automation for operational productivity and efficiency by connecting virtual and physical worlds in an industry. With Industry 4.0 being unable to address and meet increased drive of personalization, the term Industry 5.0 was coined for addressing personalized manufacturing and empowering humans in manufacturing processes. The onset of the term Industry 5.0 is observed to have various views of how it is defined and what constitutes the reconciliation between humans and machines. This serves as the motivation of this paper in identifying and analyzing …
Modification Of Superabsorbent Hydrogels For Industrial Wastewater Treatment, Md. Owaleur Rahman, Md. Abdul Halim, Anjan Deb, Shafi Ahmed, Md. Wasikur Rahman, N. C. Dafader, S. M. Nur Alam, Shahjalal Khandaker, Md. Jahangir Alam
Modification Of Superabsorbent Hydrogels For Industrial Wastewater Treatment, Md. Owaleur Rahman, Md. Abdul Halim, Anjan Deb, Shafi Ahmed, Md. Wasikur Rahman, N. C. Dafader, S. M. Nur Alam, Shahjalal Khandaker, Md. Jahangir Alam
Mechanical Engineering Faculty Publications
A breakthrough in superabsorbent hydrogel (SAH) preparation was studied in the current issue by blending potato starch and acrylic acid for wastewater treatment. Gamma irradiation source (60Co irradiation) was used to irradiate SAH from 1 to 10 kGy dose at room temperature (~27°C). The swelling ratio, water absorption, equilibrium water content, and gel fraction properties of the hydrogel were investigated. The as-prepared hydrogel treated with KOH (THG) showed excellent absorption capacity but less mechanical stability compared to untreated hydrogel (UHG). The gel fraction of treated SAH was slightly lower in methanol, but the utmost in water at 5 kGy infers …
Color Tunable Aerogels/Sponge-Like Structures Developed From Fine Fiber Membranes, Alexa Villarreal, Raul Barbosa, Saptasree Bose, Bhupendra B. Srivastava, Victoria Padilla-Gainza, Karen Lozano
Color Tunable Aerogels/Sponge-Like Structures Developed From Fine Fiber Membranes, Alexa Villarreal, Raul Barbosa, Saptasree Bose, Bhupendra B. Srivastava, Victoria Padilla-Gainza, Karen Lozano
Mechanical Engineering Faculty Publications
The development of macroscopic aerogels from 1D systems, such as nanofibers, has resulted in a novel pathway to obtain porous and lightweight architectures. In this work, bright green, red, and tunable color emitting aerogels were obtained with luminescent nanofibers as the precursor system. A simple, low cost, and environmentally friendly process is followed where luminescent fillers are encapsulated within fibers which were subsequently freeze-dried to form 3D aerogels and sponge-like structures. Moreover, the aerogels/sponge-like structures show higher photoluminescence intensity than the fiber mats due to an increase of porosity which provides higher and direct interaction with the fillers and therefore …
Development Of Zinc Oxide/Hydroxyapatite/Poly(D,L-Lactic Acid) Fibrous Scaffold For Tissue Engineering Applications, Victoria Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Antonio Ledezma-Pérez, Carmen Alvarado-Canché, Raúl Loera-Valencia, Cristóbal Rodríguez, Robert Gilkerson, Carlos Trevino De Leo, Karen Lozano
Development Of Zinc Oxide/Hydroxyapatite/Poly(D,L-Lactic Acid) Fibrous Scaffold For Tissue Engineering Applications, Victoria Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Antonio Ledezma-Pérez, Carmen Alvarado-Canché, Raúl Loera-Valencia, Cristóbal Rodríguez, Robert Gilkerson, Carlos Trevino De Leo, Karen Lozano
Mechanical Engineering Faculty Publications
Scaffolds based on polymeric fibers represent an engaging biomedical device due to their particular morphology and similarity with extracellular matrices. The biggest challenge to use fibrous materials in the biomedical field is related to their favorable platform for the adhesion of pathogenic microorganisms. Therefore, their optimum performance not only depends on their bioactive potential but also on their antimicrobial properties. The aim of this work was the design of antimicrobial (zinc oxide, ZnO) and bioactive (hydroxyapatite, Hap) fibrous materials using poly(D, L-lactic acid) (PDLLA) as the polymer fiber substrate. Fiber based composite scaffolds were developed using the Forcespinning® technique. For …
Molecular Dynamic Simulation Of Diffusion In The Melt Pool In Laser Additive Alloying Process Of Co-Ni-Cr-Mn-Fe High Entropy Alloy, Mathew Farias, Han Hu, Shanshan Zhang, Jianzhi Li, Ben Xu
Molecular Dynamic Simulation Of Diffusion In The Melt Pool In Laser Additive Alloying Process Of Co-Ni-Cr-Mn-Fe High Entropy Alloy, Mathew Farias, Han Hu, Shanshan Zhang, Jianzhi Li, Ben Xu
Manufacturing & Industrial Engineering Faculty Publications
High entropy alloys (HEAs) can be manufactured in many conventional ways, but it becomes difficult of fabricating heterogeneous materials and structures. Selective Laser Melting (SLM) method generally melts pure elemental powders or prefabricated alloy powders without alloying process. In-situ alloying in SLM, which is also called Laser Additive Alloying (LAA), using pure elemental powders becomes a promising method for creating HEA with heterogeneous structures. However, the effect of the diffusion of elements in the molten pool on the formation of HEA remains unclear. In this paper, the well-discussed Cantor HEA was studied in an in-situ alloying situation, where pure elemental …
Matrix Acidizing In Carbonate Formations, Ofelia Gomez Chacon, Maysam Pournik
Matrix Acidizing In Carbonate Formations, Ofelia Gomez Chacon, Maysam Pournik
Mechanical Engineering Faculty Publications
Matrix acidizing in carbonate reservoirs is a process that has been long used to increase productivity in oil and gas producing formations. The main goal is to create wormholes that bypass the damage in the formation. Hydrochloric acid (HCl) is the main acid used for this; however, it has several disadvantages that affect the success of these treatments. Its high reaction rate, inability to divert, and corrosive nature are a few of the reasons why research in this area has focused on finding alternative fluids. This paper discusses studies on successful alternatives to HCl. It has been observed that emulsified …
Spatters And Spills: Spreading Dynamics For Partially Wetting Droplets, Sylvia C. L. Durian, Sam Dillavou, Kwame Markin, Adrian Portales, Bryan O. Torres Maldonado, William T. M. Irvine, Paulo E. Arratia, Douglas J. Durian
Spatters And Spills: Spreading Dynamics For Partially Wetting Droplets, Sylvia C. L. Durian, Sam Dillavou, Kwame Markin, Adrian Portales, Bryan O. Torres Maldonado, William T. M. Irvine, Paulo E. Arratia, Douglas J. Durian
Mechanical Engineering Faculty Publications
We present a solvable model inspired by dimensional analysis for the time-dependent spreading of droplets that partially wet a substrate, where the spreading eventually stops and the contact angle reaches a nonzero equilibrium value. We separately consider small droplets driven by capillarity and large droplets driven by gravity. To explore both regimes, we first measure the equilibrium radius vs a comprehensive range of droplet volumes for four household fluids, and we compare the results with predictions based on minimizing the sum of gravitational and interfacial energies. The agreement is good and gives a reliable measurement of an equilibrium contact angle …