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University of Texas Rio Grande Valley

2020

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Articles 1 - 30 of 89

Full-Text Articles in Engineering

River & Estuary Observation Network: Refinement Of Stage Height Sensor Subsystem For Low Cost And High Reliability, W. D. Kirkey, C. B. Fuller, P. O'Brien, P. J. Kirkey, Ahmed Mahmoud, Andrew Ernest, Javier Guerrero Dec 2020

River & Estuary Observation Network: Refinement Of Stage Height Sensor Subsystem For Low Cost And High Reliability, W. D. Kirkey, C. B. Fuller, P. O'Brien, P. J. Kirkey, Ahmed Mahmoud, Andrew Ernest, Javier Guerrero

Civil Engineering Faculty Publications and Presentations

A system comprised of software and on-site measurements is presented for accurately obtaining water stage data from vented or non-vented submersible pressure sensors installed at autonomous stream gauging stations. The system accounts for pressure sensor offset errors, water density, and local gravitational acceleration to produce a stage height reading which is accurate to either ±0.01 ft (±3 mm) or to the accuracy limit of the sensor, whichever is greater. A 2nd order polynomial expression for determination of water density from temperature and salinity is developed and found to be sufficiently accurate for this purpose. Simulated stage measurements performed in the …


Fabrication Of Forcespinning® Nanofibers Incorporating Nopal Extract, Cristobal Rodriguez, Victoria Padilla, Karen Lozano, J. Andrew Mcdonald, Luis Materon, Alejandra Chapa, Fariha Ahmad, Carlos Trevino De Leon, Robert Gilkerson Dec 2020

Fabrication Of Forcespinning® Nanofibers Incorporating Nopal Extract, Cristobal Rodriguez, Victoria Padilla, Karen Lozano, J. Andrew Mcdonald, Luis Materon, Alejandra Chapa, Fariha Ahmad, Carlos Trevino De Leon, Robert Gilkerson

Biology Faculty Publications and Presentations

In this study, nanofibers composed of Opuntia cochenillifera nopal mucilage (N) extract combined with chitosan (CH) and pullulan (PL) (N/CH/PL) were produced via Forcespinning®. The developed nonwoven composite membranes are comprised of long, continuous, and homogenous fibers with fiber average diameter varying between 251±77 nm and 406±127 nm depending on the concentration of N. After crosslinking, the developed membranes were highly stable in water. The water absorption capacity of the N/CH/PL composite nanofiber membranes was shown to be 65% higher when compared to the CH/PL nanofiber membranes. Nopal dipcoated membranes show inhibition of gram-negative Escherichia coli, indicating antibacterial properties. These …


Microsoft’S Surface Pro 4 Performance Under Denial Of Service Attack, Adrian Guerrero Dec 2020

Microsoft’S Surface Pro 4 Performance Under Denial Of Service Attack, Adrian Guerrero

Theses and Dissertations

Microsoft Surface Pro 4 (SP4) is a new device in the line of hybrid computers today. It aims to work as both as table and laptop computer. There are multiple versions of SP4 that include devices equipped with i3, i5 and i7 core processors.

This makes SP4 a great addition for hospital, clinics or schools for its portability and features. As these locations can be prone to cyber-attacks, we plan to test this computer’s reliability and performance under cybersecurity attacks. The device tested is built with Intel Core i7-6650U 2.21 GHz processor with automatic overclocking capabilities up to 3.4 GHz, …


Optimizing A Railroad Bearing Condition-Monitoring Algorithm For Use With An Onboard Wireless Low-Power Sensor Module, Jonas Regan Leano Cuanang Dec 2020

Optimizing A Railroad Bearing Condition-Monitoring Algorithm For Use With An Onboard Wireless Low-Power Sensor Module, Jonas Regan Leano Cuanang

Theses and Dissertations

An algorithm that utilizes vibration measurements was developed by the UTRGV Center for Railway Safety to monitor the condition of railroad bearings. This algorithm uses the data collected from accelerometers on the bearing adapters to determine if there is a defect, where the defect is within the bearing, and the approximate size of the defect. Laboratory testing was performed on the UTCRS single bearing test rig. A four-second sample window of the recorded vibration data is used by the algorithm to reliably identify the defective component inside the bearing with up to a 100% confidence level. However, considerable computational power …


The Optimization Of Efficiency And Infrastructure For Modern Potable Water Treatment Plants, Brent A. Dekock Dec 2020

The Optimization Of Efficiency And Infrastructure For Modern Potable Water Treatment Plants, Brent A. Dekock

Theses and Dissertations

The USDOE Industrial Assessment Centers (IACs) is a program that is designed to help small and medium-sized manufacturing facilities reduce their overall costs and improve energy efficiency. This includes improving potable water treatment plants which supply water throughout the country. This thesis covers the process of how IAC branches and water treatment facilities generally operate, as well as several assessment recommendations that have been developed by a branch of the IAC for several water treatment plants based in the Rio Grande Valley of Texas. The steps of the assessment and water treatment process are described, and several cost saving measures …


Electromagnetic Interference Shielding Effectiveness Of Interlayered Systems Containing Metal-Oxide, Conducting Polymer And Carbon Nanotube Reinforced Polymeric Composites, Shaik Merkatur Hakim Marjuban Dec 2020

Electromagnetic Interference Shielding Effectiveness Of Interlayered Systems Containing Metal-Oxide, Conducting Polymer And Carbon Nanotube Reinforced Polymeric Composites, Shaik Merkatur Hakim Marjuban

Theses and Dissertations

The Electromagnetic Interference (EMI) Shielding Effectiveness (SE) has become one of the important requirements for the devices associated with telecommunication systems consisting of large frequency bands. The degradation of the quality of transmitting signal influenced by frequencies emitting from external sources can be reduced by covering the circuits of the devices by EMI Shielding materials like polymer composites, metal-based nanofiber mats, the metal of oxide films, etc. The investigation strives for the attenuation of EMI by introducing two composite mats from conducting polymer-based, multiwalled carbon nanotubes (MWCNTs) coated Nylon 6 nanofiber composites. Two other composite mats are also developed by …


Traffic Time Headway Prediction And Analysis: A Deep Learning Approach, Saumik Sakib Bin Masud Dec 2020

Traffic Time Headway Prediction And Analysis: A Deep Learning Approach, Saumik Sakib Bin Masud

Theses and Dissertations

In the modern world of Intelligent Transportation System (ITS), time headway is a key traffic flow parameter affecting ITS operations and planning. Defined as “the time difference between any two successive vehicles when they cross a given point”, time headway is used in various traffic and transportation engineering research domains, such as capacity analysis, safety studies, car-following, and lane-changing behavior modeling, and level of service evaluation describing stochastic features of traffic flow. Advanced travel and headway information can also help road users avoid traffic congestion through dynamic route planning, for instance. Hence, it is crucial to accurately model headway distribution …


Cyber Security Evaluation Of Centos Red Hat Based Operating System Under Cyber Attack With Increasing Magnitude, William E. R. Rivas Dec 2020

Cyber Security Evaluation Of Centos Red Hat Based Operating System Under Cyber Attack With Increasing Magnitude, William E. R. Rivas

Theses and Dissertations

The increasing interest in ‘always-connected’ devices and the Internet of Things has led to electronic devices with Internet connectivity becoming a staple in modern household and workplace. Consequently, this increase has also led to an increase in vulnerable devices, ripe for hijacking by a malicious third party. Distributed Denial of Service (DDoS) attacks have consistently been an issue since the birth of the Internet. With the large number of devices available today, the strength and consistency of these attacks has only grown and will continue to grow. Since, depending on certain variables, these DDoS attacks can effectively render a target …


Water-Soluble Polymers With Ceramic/Metal Nanoparticles For Use As Anode Materials In Lithium-Ion And Sodium-Ion Batteries, Roberto Orrostieta Chavez Dec 2020

Water-Soluble Polymers With Ceramic/Metal Nanoparticles For Use As Anode Materials In Lithium-Ion And Sodium-Ion Batteries, Roberto Orrostieta Chavez

Theses and Dissertations

Aqueous solutions of poly(vinylpyrrolidone) (PVP) with 20, 25, and 28 wt.% concentrations were successfully spun into fibers by centrifugal spinning. The pristine PVP fibers were annealed and carbonized to produce flexible carbon fibers for use as binder-free anodes in lithium-ion and sodium-ion batteries. These flexible carbon fibers were prepared by developing a novel three-step heat treatment to reduce the residual stresses in the pristine PVP precursor fibers and to prevent fiber degradation during carbonization. The average diameters of the pristine, annealed, and carbonized fibers were obtained using scanning electron microscopy (SEM), which showed that the average diameter of the carbon …


A Study On The Triaxial Shear Behavior Of Geosynthetic Reinforced Soil By Discrete Element Method, Md Wasif Zaman Dec 2020

A Study On The Triaxial Shear Behavior Of Geosynthetic Reinforced Soil By Discrete Element Method, Md Wasif Zaman

Theses and Dissertations

A 3D DEM model using Particle Flow Code (PFC3D) software was developed utilizing a bonded-ball flexible membrane approach to study cohesionless soil as a discontinuous discrete material. The 3D model was calibrated and verified with experimental data, and a sensitivity analysis was carried out for the microparameters. Triaxial tests were simulated to observe the stress-strain curves and volumetric changes, as well as the strength parameters of soils consisting of spherical particles with different gradations but the same porosity. One important finding is that the relationships between particle size and deviatoric stress, internal friction angle, and dilatancy angle were found to …


Optimizing Energy Power Consumption Of Freight Railroad Bearings Using Experimental Data, Carlos Eliasar Lopez Iii Dec 2020

Optimizing Energy Power Consumption Of Freight Railroad Bearings Using Experimental Data, Carlos Eliasar Lopez Iii

Theses and Dissertations

Throughout the railway industry, trains use systems that record total energy efficiency of a train but not energy efficiency or consumption by components. Monitoring freight bearing power consumption can support the railroad industry efforts to maintain the railroad economic competitiveness and minimize the environmental impact.

For more than a decade now, the University Transportation Center for Railway Safety (UTCRS) at the University of Texas Rio Grande Valley (UTRGV) has been collecting power consumption data for railroad bearings under various loads, speeds, ambient temperatures, bearing condition, and bearing classes. Specifically, data such as temperatures, voltages, speed, and load were collected to …


Security Evaluation Of Microsoft’S Windows Under Cyber-Flood Attacks, Christina Y. Navarro Dec 2020

Security Evaluation Of Microsoft’S Windows Under Cyber-Flood Attacks, Christina Y. Navarro

Theses and Dissertations

Cyberattacks are quite common occurrences today as such can compromise entire networks producing collective vulnerabilities. As shown herein, manifold experimental findings exhibit ramifications for a cyberattack victim during multiple simulations. All experiments were conducted with Apple’s iMac, the victim system, and different editions of Microsoft Windows 10 and Windows 8.1.

Cyberattacks herein categorize as Distributed Denial of Service (DDoS) attacks including Smurf, Ping Flood, Transmission Control Protocol-Synchronize (TCP-SYN) Flood, and User Datagram Protocol (UDP) Flood attacks. Experimental results from each cyberattack are recordings of computer activities such as memory consumption, disk utilization, and overall processor utilization.

DDoS attack simulations include …


Performance And Efficiency Evaluation Of Stormwater Management Lids Using Pcswmm: Numerical Modeling And Sensitivity Analysis, Abdullah Al Fatta Dec 2020

Performance And Efficiency Evaluation Of Stormwater Management Lids Using Pcswmm: Numerical Modeling And Sensitivity Analysis, Abdullah Al Fatta

Theses and Dissertations

Implementation of Low Impact Development systems (LIDs) can reduce the detrimental effects of urbanization. In this study, performance of both conventional drainage system and bioretention swales LID green infrastructure was assessed. Personal Computer Storm Water Management Model (PCSWMM) was used to investigate the performance by producing runoff hydrographs. Calibration and validation were conducted with independent storm events to minimize the gap between the simulated and observed outflow. Among different sensitive parameters, saturated hydraulic conductivity, suction head, percent initially saturated, Manning’s N for impervious area, were used in calibration. Each storm event resulted coefficient of determination (R2) values of 0.656 or …


Preparation And Characterization Of Dc Magnetron Sputtered Thin Films, Al Amin Dec 2020

Preparation And Characterization Of Dc Magnetron Sputtered Thin Films, Al Amin

Theses and Dissertations

Plasma enhanced DC magnetron sputtering is a well-known technique for thin film deposition. Thin film has wide range of applications in many fields such as electronics, optics, communication, decoration, biosystem and medical. Among them, antibacterial and biocompatible thin film coating has attracted researcher’s attention to prevent the healthcare-associated infections (HAIs) during the surgical operations as well as the implantation of foreign devices inside human body. This research has been divided into two sections. In first section, titanium (Ti) was deposited on glass substrate at DC power of 200 W, argon-nitrogen plasma, and temperature of 25 ˚C. Later this Ti-coated glass …


A Python-Based Brain-Computer Interface Package For Neural Data Analysis, Md Hasan Anowar Dec 2020

A Python-Based Brain-Computer Interface Package For Neural Data Analysis, Md Hasan Anowar

Theses and Dissertations

Anowar, Md Hasan, A Python-based Brain-Computer Interface Package for Neural Data Analysis. Master of Science (MS), December, 2020, 70 pp., 4 tables, 23 figures, 74 references.

Although a growing amount of research has been dedicated to neural engineering, only a handful of software packages are available for brain signal processing. Popular brain-computer interface packages depend on commercial software products such as MATLAB. Moreover, almost every brain-computer interface software is designed for a specific neuro-biological signal; there is no single Python-based package that supports motor imagery, sleep, and stimulated brain signal analysis. The necessity to introduce a brain-computer interface package that …


The Implementation And Comparison Of Fuzzy Logic Control Systems To Modern Control Methods On Low-Cost Hardware, Cristian A. Barron Dec 2020

The Implementation And Comparison Of Fuzzy Logic Control Systems To Modern Control Methods On Low-Cost Hardware, Cristian A. Barron

Theses and Dissertations

Modern control engineering provides many options to automate systems for which a mathematical model is required. Another control does not rely on the mathematical model of the system and is known as fuzzy logic control. In this study, a literature review is conducted on existing control systems strategies such as proportional integral and derivative (PID), linear quadratic regulator (LQR), and fuzzy logic controller (FLC), the complexity of the systems they control, and their strengths and weaknesses. In addition, a series of experiments are conducted, both through simulations in MATLAB Simulink and using their implementation using the actual physical hardware to …


Effect Of Adding Palm Fiber To Thermal Conductivity Of Quick Set Concrete, Monica Garcia Dec 2020

Effect Of Adding Palm Fiber To Thermal Conductivity Of Quick Set Concrete, Monica Garcia

Theses and Dissertations

As climate change becomes a more dire issue and more readily accepted by those in power, the demand for local and systemic solutions grows louder. In urban environments, one issue of concern is the contribution of anthropogenic heat from buildings which contributes to localized warming of the environment. A method that can reduce anthropogenic heat is decreasing the thermal conductivity of building materials. The objective of this study is to examine the possibility of using palm fibers to reduce the thermal conductivity of quick-set concrete samples. The data gathered in this study are used to determine the thermal conductivity value …


The Design, Fabrication, And Testing Of A Cooling Garment, Richard James Garza Dec 2020

The Design, Fabrication, And Testing Of A Cooling Garment, Richard James Garza

Theses and Dissertations

The aim of this research is to design a device or technology capable of cooling the user – such as a college student walking to class, for example – in a manner as convenient as putting on a jacket. The idea is to use the peltier effect – a phenomenon in which two dissimilar semi-conductors heat up and cool down with the application of an electric current – as the source of heat absorption used to cool the user. In this research it will be determined whether or not it is feasible to use such a phenomenon to keep the …


Assessing The Performance Of Reconditioned Railroad Tapered-Roller Bearings Used In Freight Rail Service, Veronica Valeria Hernandez Dec 2020

Assessing The Performance Of Reconditioned Railroad Tapered-Roller Bearings Used In Freight Rail Service, Veronica Valeria Hernandez

Theses and Dissertations

The rail industry currently utilizes two wayside detection systems to monitor the health of freight railcar bearings in service: The Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). Bearings that are removed from service are sent to specialized facilities where they undergo a reconditioning process before the bearings can be returned to rail service. The reconditioning process has been used for decades although there has been no previous study on the effectiveness of the reconditioning process on defective bearings that were removed from service. This persuaded the researchers from the University Transportation Center for Railway Safety (UTRCS) …


Ac Electrokinetic Effect Of V-Electrode Pattern On Microfluids, Mohammad Salman Parvez Dec 2020

Ac Electrokinetic Effect Of V-Electrode Pattern On Microfluids, Mohammad Salman Parvez

Theses and Dissertations

Electrokinetics has been used for guiding, pumping, and manipulating microfluidic particles for many years in the field of Biomedical, Microbiology, Chemistry, Medicine, and other fields of research, which makes it a ubiquitous tool for the multidisciplinary research on microfluidics. Between these two Alternating Current (AC) Electrokinetics have been proven to be more feasible for the researcher than the other one. In this research, we have investigated AC Electrokinetics and s effect on a new electrode configuration called V-electrode pattern. The V-electrode has been inspired and modified from the previous research work on the Orthogonal Electrode Pattern. In this research, this …


Mono And Multi-Objective Optimization And Modeling Of Machining Performance In Face Milling Of Ti6al4v Alloy, Al Mazedur Rahman Dec 2020

Mono And Multi-Objective Optimization And Modeling Of Machining Performance In Face Milling Of Ti6al4v Alloy, Al Mazedur Rahman

Theses and Dissertations

Titanium alloys are extensively used in numerous industries like aerospace, automotive, military, etc., due to their exclusive characteristics. But machining these alloys has always been challenging for manufacturers. This research investigates the effect of radial depth of cut on cutting forces, tool life, surface roughness (Ra), and material removal rate (MRR) during face milling of Ti6Al4V alloy. It also aims to perform mono and multi-objective optimization of response characteristics to determine the optimal input parameters, namely cutting speed, feed rate, and radial depth of cut. Taguchi method and analysis of variance (ANOVA) have been used for mono-objective optimization, whereas Taguchi-based …


Fabrication And Flow Dynamics Analysis Of Micromixer For Lab-On-A-Chip Devices, Md Fazlay Rubby Dec 2020

Fabrication And Flow Dynamics Analysis Of Micromixer For Lab-On-A-Chip Devices, Md Fazlay Rubby

Theses and Dissertations

The miniaturized systems designed for lab-on-a-chip (LOC) technologies are generally implemented with a micro-scale mixer to provide intimate contact between the reagent molecules for interactions and chemical reactions. The exponential increase of research in microfabrication and microfluidic applications highlights the importance of understanding the theory and mechanism that governs mixing at the microscale level. In this study, the fabrication of an active and passive micromixer was discussed. The optimized state of art soft lithography and 3D printing was used as a microfabrication technique. The challenges at different fabrication steps were presented along with the modifications. Microelectrodes were integrated with the …


Improvement Of Light Intensity And Efficiency Of N-Zno/Nio/P-Gan Heterojunction-Based White Light Emitting Diodes Using Micro-/Nanolens Array, Apurba Adhikary, Md Shamim Ahsan, Md Mahbub Hossain, Md Bipul Hossain, S. H. Shah Newaz, Farid Ahmed, Ik-Bu Sohn Nov 2020

Improvement Of Light Intensity And Efficiency Of N-Zno/Nio/P-Gan Heterojunction-Based White Light Emitting Diodes Using Micro-/Nanolens Array, Apurba Adhikary, Md Shamim Ahsan, Md Mahbub Hossain, Md Bipul Hossain, S. H. Shah Newaz, Farid Ahmed, Ik-Bu Sohn

Manufacturing & Industrial Engineering Faculty Publications and Presentations

Our study proposes a technique to enhance light extraction efficiency of light emitting diodes (LEDs) by incorporating various micro-/nanolens arrays (MNLAs) on the substrate layer, which in turn increases the external quantum efficiency (EQE) of the LEDs. To simulate the LEDs, we utilized the finite difference time domain method. To achieve a white LED, we inserted a thin layer of NiO at the interface between the n-type ZnO and the p-type GaN. The basic n-ZnO/NiO/p-GaN heterojunction-based LED exhibited an EQE of 10.99% where the effective refractive index of the LED structure was 1.48. The EQE was further increased by engraving …


Editorial: Carbon- And Inorganic-Based Nanostructures For Energy Applications, Federico Cesano, M. Jasim Uddin, Yuanbing Mao, Muhammad N. Huda Nov 2020

Editorial: Carbon- And Inorganic-Based Nanostructures For Energy Applications, Federico Cesano, M. Jasim Uddin, Yuanbing Mao, Muhammad N. Huda

Chemistry Faculty Publications and Presentations

No abstract provided.


Grow Local Manufacturing Along Us/Mexico Border Region For An Integrated Supply Chain In The Post Covid-19 Era, Jianzhi Li Nov 2020

Grow Local Manufacturing Along Us/Mexico Border Region For An Integrated Supply Chain In The Post Covid-19 Era, Jianzhi Li

Manufacturing & Industrial Engineering Faculty Publications and Presentations

The current coronavirus disease pandemic, plus the strong movement of manufacturing reshoring, provide a unique opportunity for many US regions to grow local manufacturers. This technical note attempts to review the current situation and trend in US manufacturing. We then discuss challenges and necessary steps, such as asset mapping, required to grow local suppliers. Suggestions are then made to support growing local suppliers along the US/Mexico border region.


Investigation Of The Hall-Petch Relationship Using Strain Gradient Plasticity Model For Finite Deformation Framework, Yooseob Song Nov 2020

Investigation Of The Hall-Petch Relationship Using Strain Gradient Plasticity Model For Finite Deformation Framework, Yooseob Song

Civil Engineering Faculty Publications and Presentations

The Hall-Petch relationship in metals is investigated using the strain gradient plasticity theory within the finite deformation framework. For this purpose, the thermodynamically consistent constitutive formulation for the coupled thermomechanical gradient-enhanced plasticity model is developed. The corresponding finite element method is performed to investigate the characteristics of the Hall-Petch relationship in metals. The proposed model is established based on an extra Helmholtz-type partial differential equation, and the nonlocal quantity is calculated in a coupled method based on the equilibrium conditions. An excellent agreement between the simulation results and the test data is resulted in the Hall-Petch graph. Furthermore, it is …


Electromagnetic-Triboelectric-Hybrid Energy Tile For Biomechanical Green Energy Harvesting, Elaijah Islam, Abu Musa Abdullah, Aminur Rashid Chowdhury, Farzana Tasnim, Madelyne Martinez, Carolina Olivares, Karen Lozano, Mohammed Uddin Nov 2020

Electromagnetic-Triboelectric-Hybrid Energy Tile For Biomechanical Green Energy Harvesting, Elaijah Islam, Abu Musa Abdullah, Aminur Rashid Chowdhury, Farzana Tasnim, Madelyne Martinez, Carolina Olivares, Karen Lozano, Mohammed Uddin

Chemistry Faculty Publications and Presentations

Highlights

  • Hybrid nanogenerator based floor-tile was developed to convert the Bio-Mechanical energy of human footsteps to Electrical Energy.

  • Hybridization of Triboelectric Nanogenerator and Electro-Magnetic Generator consisting of Aluminum and Kapton.

  • MoS2 is working as an electron acceptor.

  • The maximum output is 1200V as open-circuit voltage, 5mA as short-circuit current, and 6W as power.

  • Produces 20% more power than a commercially sold energy-harvester floor tile.

Abstract

Since the invention of Piezoelectric Nanogenerator in 2006, nanogenerators has become an attractive technology to the researchers for scavenging mechanical energy from the ambient environment for real life applications. Hybridization of these nanogenerators has been …


Centrifugally Spun Mats Based On Biopolyesters/Hydroxyapatite And Their Potential As Bone Scaffolds, Victoria Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Eduardo Saucedo, Karen Lozano, Vanessa Montaño-Machado,, Diego Mantovani Nov 2020

Centrifugally Spun Mats Based On Biopolyesters/Hydroxyapatite And Their Potential As Bone Scaffolds, Victoria Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Eduardo Saucedo, Karen Lozano, Vanessa Montaño-Machado,, Diego Mantovani

Mechanical Engineering Faculty Publications and Presentations

This work studied the potential of centrifugal spinning for the production of fibrous materials based on poly(D,L-lactic acid) (PDLLA) and poly(3-hydroxybutyrate) (PHB) with hydroxyapatite nanoparticles (n-Hap). The influence of n-Hap concentration (5, 10, and 15 wt.%) and spinneret angular speed on the final fiber morphology were analyzed. Further experimental evaluations were implemented to determine the effect of n-Hap on the thermal and mechanical performance. The optimum parameters that show a balance among high yield production of homogeneous fibers with the smallest fiber average diameter were found to be at 5 wt.% of n-Hap processed at 7000 rpm for PDLLA, and …


Characterization And Performance Of Minimum Quantity Lubricants In Through-Tool Drilling, Amla Patil, Jay Raval, Tim Bangma, Immanuel Edinbarough, Bruce Tai, David Stephenson, Suleiman Obeidat, Wayne Nguyen Hung Oct 2020

Characterization And Performance Of Minimum Quantity Lubricants In Through-Tool Drilling, Amla Patil, Jay Raval, Tim Bangma, Immanuel Edinbarough, Bruce Tai, David Stephenson, Suleiman Obeidat, Wayne Nguyen Hung

Manufacturing & Industrial Engineering Faculty Publications and Presentations

This study characterized airborne microdroplet diameters and size distribution from two commercially available lubricants A and B for internal minimum quantity lubrication (MQL). The effects of air pressure, oil channel size, physical properties of lubricants on the resultant microdroplets and through-tool MQL drilling performance were studied. Airborne microdroplet diameters were highly sensitive to the coolant channel sizes and air pressure. Cluster method was used to divide microdroplets into smaller clusters for comparison. Experimental data show that the average airborne microdroplet of lubricant B was larger than that of lubricant A at different air pressures and channel sizes. The contact angle …


Effect Of Additional Weight On Human Squat Exercise Stability: Ground Reaction Forces And Centers Of Pressure, Jose Galarza, Dumitru Carantu Oct 2020

Effect Of Additional Weight On Human Squat Exercise Stability: Ground Reaction Forces And Centers Of Pressure, Jose Galarza, Dumitru Carantu

Mechanical Engineering Faculty Publications and Presentations

The main focus of this work is to investigate the effect of weight on the stability of human squat exercise. The squat exercise is a common daily activity. Experiments are conducted using one human subject. A VICON motion analysis system integrated with Force Plates is utilized for these experiments. An experimental protocol is developed and followed. This work analyzes the time series of the normal component of the ground reaction forces and each coordinate of the center of pressure. These time series are used to estimate the Lyapunov Exponents using Rosenstein method. MATLAB software package is used for this investigation. …