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Articles 211 - 240 of 618
Full-Text Articles in Mechanical Engineering
Centrifugally Spun Mats Based On Biopolyesters/Hydroxyapatite And Their Potential As Bone Scaffolds, Victoria M. Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Eduardo Saucedo, Karen Lozano, Vanessa Montaño-Machado,, Diego Mantovani
Centrifugally Spun Mats Based On Biopolyesters/Hydroxyapatite And Their Potential As Bone Scaffolds, Victoria M. Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Eduardo Saucedo, Karen Lozano, Vanessa Montaño-Machado,, Diego Mantovani
Mechanical Engineering Faculty Publications
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 …
Comparison Of Three Commercial Automatic Boom Height Systems For Agricultural Sprayers, Travis A. Burgers, John D. Gaard, Brian J. Hyronimus
Comparison Of Three Commercial Automatic Boom Height Systems For Agricultural Sprayers, Travis A. Burgers, John D. Gaard, Brian J. Hyronimus
Mechanical Engineering Faculty Publications
Automatic boom height systems reduce the variability of agricultural sprayer boom height. Consistent boom height is important for three key reasons: to reduce uneven spray dispersion if the boom is too low, to reduce spray droplet drift if the boom is too high, and to reduce damage to the boom or crop if the boom is too low. No data is available comparing commercial boom height systems. Three leading North American automatic boom height systems were compared: John Deere BoomTrac Pro (System A), Raven AutoBoom® XRT (System B), and Norac UC5TM Passive Roll (System C) on a John Deere R4045 …
Teaching Engineering Virtually: A Rapid Response To Address The Academic Challenges Generated By Covid-19, Eleazar Marquez, Samuel Garcia
Teaching Engineering Virtually: A Rapid Response To Address The Academic Challenges Generated By Covid-19, Eleazar Marquez, Samuel Garcia
Mechanical Engineering Faculty Publications
In this study, an alternative pedagogical model was established to address the academic challenges posed when undergraduate engineering students in a private university in Texas were mandated to seek off-campus housing due to the outbreak of COVI-19. As a result of the rapid transition to remote instruction, traditional and effective pedagogical methods implemented for in-person instruction had to be modified to overcome challenges such as the lack of academic resources, established campus practices that promote effective learning (e.g., study groups), and time-zone differences. Additionally, the instructional format had to be adjusted to ensure that the academic development of the students …
High Pressure Responsive Luminescence Of Flexible Eu3+ Doped Pvdf Fibrous Mats, Carlos Hernandez, Santosh K. Gupta, Jose P. Zuniga, Jorge Vidal, Rene Galvan, Hector Guzman, Lilian N. Chavez, Karen Lozano, Yuanbing Mao
High Pressure Responsive Luminescence Of Flexible Eu3+ Doped Pvdf Fibrous Mats, Carlos Hernandez, Santosh K. Gupta, Jose P. Zuniga, Jorge Vidal, Rene Galvan, Hector Guzman, Lilian N. Chavez, Karen Lozano, Yuanbing Mao
Mechanical Engineering Faculty Publications
Exploring lanthanide doped materials and their high-pressure optical properties is important from the perspective of designing pressure sensors, piezoelectric materials, scintillators, and optoelectronic devices, just to mention a few. Understanding the high-pressure optical properties of polymeric fibrous mats provides significant advantages in terms of flexibility, tunability, facile processability, and malleability. In this work, we have developed flexible polyvinylidene difluoride (PVDF) fibrous mats doped with an Eu3+ source of Eu(NO3)3·5H2O (EN-PF) or Eu2(SO4)3 (ES-PF) by a Forcespinning® method. Microstructural analysis of these two systems indicates that Eu(NO3)3·5H2O and Eu2(SO4)3 are homogeneously distributed and dispersed into the PVDF matrix. Fiber formation …
In-Situ Calibrated Modeling Of Residual Stresses Induced In Machining Under Various Cooling And Lubricating Environments, Julius M. Schoop
In-Situ Calibrated Modeling Of Residual Stresses Induced In Machining Under Various Cooling And Lubricating Environments, Julius M. Schoop
Mechanical Engineering Faculty Publications
Although many functional characteristics, such as fatigue life and damage resistance depend on residual stresses, there are currently no industrially viable ‘Digital Process Twin’ models (DPTs) capable of efficiently and quickly predicting machining-induced stresses. By leveraging advances in ultra-high-speed in-situ experimental characterization of machining and finishing processes under plane strain (orthogonal/2D) conditions, we have developed a set of physics-based semi-analytical models to predict residual stress evolution in light of the extreme gradients of stress, strain and temperature, which are unique to these thermo-mechanical processes. Initial validation trials of this novel paradigm were carried out in Ti-6Al4V and AISI 4340 alloy …
Tunable Cspb(Br/Cl)3 Perovskite Nanocrystals And Further Advancement In Designing Light Emitting Fiber Membranes, Sk Shamim Hasan Abir, Santosh K. Gupta, A. Ibrahim, Bhupendra B. Srivastava, Karen Lozano
Tunable Cspb(Br/Cl)3 Perovskite Nanocrystals And Further Advancement In Designing Light Emitting Fiber Membranes, Sk Shamim Hasan Abir, Santosh K. Gupta, A. Ibrahim, Bhupendra B. Srivastava, Karen Lozano
Mechanical Engineering Faculty Publications
Cesium lead halide perovskite nanocrystals (NCs) have drawn a great deal of interest in optoelectronic and photonic applications due to their intrinsic and attractive photoluminescence properties. Though, their commercially viability is of concern due to their intrinsic instability. In this study, blue and green luminous PMMA-CsPbX3(X=Cl/Br) fibers were fabricated via forcespinning technique, where the polymer matrix encapsulated the NCs. Blue CsPbX3 NCs (b- CPX NCs) were synthesized at ambient conditions while blue to green CsPbX3 NCs (g-CPX NCs) fine color tuning was obtained after heat treatment at 150°C.Field emission scanning electron microscopy (FESEM) shows fibers with diameters in the single …
Development Of Multifunctional Materials Based On Poly(Ether Ether Ketone) With Improved Biological Performances For Dental Applications, Vanessa Montaño-Machado, Pascale Chevallier, Linda Bonilla-Gameros, Francesco Copes, Chiara Quarta, José De Jesús Kú-Herrera, Florentino Soriano, Victoria Padilla-Gainza, Graciela Morales, Diego Mantovani
Development Of Multifunctional Materials Based On Poly(Ether Ether Ketone) With Improved Biological Performances For Dental Applications, Vanessa Montaño-Machado, Pascale Chevallier, Linda Bonilla-Gameros, Francesco Copes, Chiara Quarta, José De Jesús Kú-Herrera, Florentino Soriano, Victoria Padilla-Gainza, Graciela Morales, Diego Mantovani
Mechanical Engineering Faculty Publications
The main target for the future of materials in dentistry aims to develop dental implants that will have optimal integration with the surrounding tissues, while preventing or avoiding bacterial infections. In this project, poly(ether ether ketone) (PEEK), known for its suitable biocompa-tibility and mechanical properties for dental applications, was loaded with 1, 3, and 5 wt.% ZnO nanoparticles to provide antibacterial properties and improve interaction with cells. Sample cha-racterization by X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) as well as mechanical properties showed the presence of the nanoparticles and their effect in PEEK matrices, preserving their …
Defect Detection In Freight Railcar Tapered-Roller Bearings Using Vibration Techniques, Constantine Tarawneh, Joseph Montalvo, Brent Wilson
Defect Detection In Freight Railcar Tapered-Roller Bearings Using Vibration Techniques, Constantine Tarawneh, Joseph Montalvo, Brent Wilson
Mechanical Engineering Faculty Publications
Currently, there are two types of defect detection systems used to monitor the health of freight railcar bearings in service: wayside hot-box detection systems and trackside acoustic detection systems. These systems have proven to be inefficient in accurately determining bearing health, especially in the early stages of defect development. To that end, a prototype onboard bearing condition monitoring system has been developed and validated through extensive laboratory testing and a designated field test in 2015 at the Transportation Technology Center, Inc. in Pueblo, CO. The devised system can accurately and reliably characterize the health of bearings based on developed vibration …
Centrifugally Spun Tio2/C Composite Fibers Prepared From Tis2/Pan Precursor Fibers As Binder-Free Anodes For Libs, Jorge Lopez, Ramiro Gonzalez, Jonathan Ayala, Jesus Cantu, Alexandria Castillo, Jason Parsons, Timothy P. Lodge, Mataz Alcoutlabi
Centrifugally Spun Tio2/C Composite Fibers Prepared From Tis2/Pan Precursor Fibers As Binder-Free Anodes For Libs, Jorge Lopez, Ramiro Gonzalez, Jonathan Ayala, Jesus Cantu, Alexandria Castillo, Jason Parsons, Timothy P. Lodge, Mataz Alcoutlabi
Mechanical Engineering Faculty Publications
TiO2/carbon composite-fiber anodes for lithium ion batteries were prepared through the centrifugal spinning of TiS2/polyacrylonitrile (PAN) precursor fibers and subsequent thermal treatment. The TiS2/PAN precursor solutions were prepared by mixing TiS2 nanoparticles (a 2-D layered structure) with PAN in N, N-dimethylformamide (DMF). The thermal treatment of the TiS2 in the centrifugally spun PAN fibers resulted in TiO2/carbon composite fibers. The structure of TiO2 nanoparticles embedded in the carbon-fiber matrix synthesized from the TiS2 starting material may accommodate high amounts of Li ions. The TiO2/C structure may lead to increased specific capacity, improved stability, and enhanced electrochemical performance of the TiO2/C …
The Role Of Bed-Penetrating Kelvin–Helmholtz Vortices On Local And Instantaneous Bedload Sediment Transport, Liheng Guan, J. S. Salinas, Nadim Zgheib, S. Balachandar
The Role Of Bed-Penetrating Kelvin–Helmholtz Vortices On Local And Instantaneous Bedload Sediment Transport, Liheng Guan, J. S. Salinas, Nadim Zgheib, S. Balachandar
Mechanical Engineering Faculty Publications
We present results from open-channel, Euler–Lagrange (EL) simulations of turbulent flow over an erodible particle bed at a shear Reynolds number of Reτ=180 . Upon space and time averaging, our simulations correctly reproduce the Wong & Parker (ASCE J. Hydraul. Engng, vol. 132, issue 11, 2006, pp. 1159–1168) bedload transport relation (WP). However, local and instantaneous sediment flux shows orders of magnitude scatter around the WP prediction. Visualization of the vortical structures using swirling strength shows the existence of bed-penetrating Kelvin–Helmholtz (KH) vortex packets, which coupled with particle inertia are primarily responsible for the large scatter. The results also show …
Campus Carbon Footprint Study At A South Texas University, Monica Garcia, Christian Florez, Diego Lopez, Jongmin Kim, Maysam Pournik
Campus Carbon Footprint Study At A South Texas University, Monica Garcia, Christian Florez, Diego Lopez, Jongmin Kim, Maysam Pournik
Mechanical Engineering Faculty Publications
A campus carbon footprint study was conducted at the University of Texas Rio Grande Valley, a Southern Texan university. This initiative was the school’s strategic plan to set a baseline for overall campus resource utilization status as well as to answer global requests to track and reduce campus greenhouse gas emissions and achieve greater sustainability on campus. For fiscal years of 2016 to 2018, an overall increase of campus carbon footprint was about 0.6%. The biggest increase was observed from sources owned or controlled by the school while the emissions associated with power usage decreased. The university’s carbon footprint was …
Numerical Reconstruction Of Spalled Particle Trajectories In An Arc-Jet Environment, Raghava S. C. Davuluri, Sean C. C. Bailey, Kaveh A. Tagavi, Alexandre Martin
Numerical Reconstruction Of Spalled Particle Trajectories In An Arc-Jet Environment, Raghava S. C. Davuluri, Sean C. C. Bailey, Kaveh A. Tagavi, Alexandre Martin
Mechanical Engineering Faculty Publications
To evaluate the effects of spallation on ablative material, it is necessary to evaluate the mass loss. To do so, a Lagrangian particle trajectory code is used to reconstruct trajectories that match the experimental data for all kinematic parameters. The results from spallation experiments conducted at the NASA HYMETS facility over a wedge sample were used. A data-driven adaptive methodology was used to adapts the ejection parameters until the numerical trajectory matches the experimental data. The preliminary reconstruction results show that the size of the particles seemed to be correlated with the location of the ejection event. The size of …
Wetting And Brazing Of Yig Ceramics Using Ag–Cuo–Tio2 Metal Filler, Wanqi Zhao, Shuye Zhang, Jian Yang, Tiesong Lin, Dusan P. Sekulic, Peng He
Wetting And Brazing Of Yig Ceramics Using Ag–Cuo–Tio2 Metal Filler, Wanqi Zhao, Shuye Zhang, Jian Yang, Tiesong Lin, Dusan P. Sekulic, Peng He
Mechanical Engineering Faculty Publications
The wetting and brazing of Y3Fe5O12 (YIG) ceramics with a Ag–8CuO–2TiO2 filler was investigated for the first time. For comparison, the wettability of a Ag–10CuO filler on YIG ceramics was similarly investigated. The Ag–8CuO–2TiO2 filler has an equilibrium contact angle of approximately 31 °C on the YIG substrate at 1000 °C; thus, its wettability is excellent. Moreover, its wettability exceeds that of Ag–10CuO. The microstructure and the interfacial structure between the filler and the substrate were determined using scanning electron microscopy, X-ray diffraction, EPMA and transmission electron microscopy. The liquid Ag–8CuO–2TiO2 filler …
Synthetic Approach Of Ternary Magnesium Niobate (Mg–Nb–O) Compounds, Md. Wasikur Rahman
Synthetic Approach Of Ternary Magnesium Niobate (Mg–Nb–O) Compounds, Md. Wasikur Rahman
Mechanical Engineering Faculty Publications
Magnesium based niobium oxides (Mg–Nb–O) were prepared by solid-state reactions owing to understand the function of transition metal oxides as promoters/catalysts for practical application. Magnesium niobate (Mg3Nb6O11) was synthesized for the first time in nearly pure form reported in this context. MgNb2O6 and Mg4Nb2O9 were prepared in oxidizing conditions; on the contrary, Mg3Nb6O11 preferred reducing environment. Stoichiometric mixtures of the precursor materials MgO, Nb2O5 and/or metallic Nb were annealed for the syntheses which revealed the effect of temperature on phase formation, reaction kinetics and heat of reaction. The products were examined by ex-situ, in-situ X-ray diffraction (XRD) and differential scanning …
Data Generated During The 2018 Lapse-Rate Campaign: An Introduction And Overview, Gijs De Boer, Adam Houston, Jamey D. Jacob, Phillip B. Chilson, Suzanne W. Smith, Brian Argrow, Dale Lawrence, Jack Elston, David Brus, Osku Kemppinen, Petra Klein, Julie K. Lundquist, Sean Waugh, Sean C. C. Bailey, Amy E. Frazier, Michael P. Sama, Christopher Crick, David G. Schmale Iii, James Pinto, Elizabeth A. Pillar-Little, Victoria Natalie, Anders Jensen
Data Generated During The 2018 Lapse-Rate Campaign: An Introduction And Overview, Gijs De Boer, Adam Houston, Jamey D. Jacob, Phillip B. Chilson, Suzanne W. Smith, Brian Argrow, Dale Lawrence, Jack Elston, David Brus, Osku Kemppinen, Petra Klein, Julie K. Lundquist, Sean Waugh, Sean C. C. Bailey, Amy E. Frazier, Michael P. Sama, Christopher Crick, David G. Schmale Iii, James Pinto, Elizabeth A. Pillar-Little, Victoria Natalie, Anders Jensen
Mechanical Engineering Faculty Publications
Unmanned aircraft systems (UASs) offer innovative capabilities for providing new perspectives on the atmosphere, and therefore atmospheric scientists are rapidly expanding their use, particularly for studying the planetary boundary layer. In support of this expansion, from 14 to 20 July 2018 the International Society for Atmospheric Research using Remotely piloted Aircraft (ISARRA) hosted a community flight week, dubbed the Lower Atmospheric Profiling Studies at Elevation – a Remotely-piloted Aircraft Team Experiment (LAPSE-RATE; de Boer et al., 2020a). This field campaign spanned a 1-week deployment to Colorado's San Luis Valley, involving over 100 students, scientists, engineers, pilots, and outreach coordinators. These …
Experimental And Mathematical Tools To Predict Droplet Size And Velocity Distribution For A Two-Fluid Nozzle, Sadegh Poozesh, Nelson K. Akafuah, Heather R. Campbell, Faezeh Bashiri, Kozo Saito
Experimental And Mathematical Tools To Predict Droplet Size And Velocity Distribution For A Two-Fluid Nozzle, Sadegh Poozesh, Nelson K. Akafuah, Heather R. Campbell, Faezeh Bashiri, Kozo Saito
Mechanical Engineering Faculty Publications
Despite progress in laser-based and computational tools, an accessible model that relies on fundamentals and offers a reasonably accurate estimation of droplet size and velocity is lacking, primarily due to entangled complex breakup mechanisms. Therefore, this study aims at using the integral form of the conservation equations to create a system of equations by solving which, the far-field secondary atomization can be analyzed through predicting droplet size and velocity distributions of the involved phases. To validate the model predictions, experiments are conducted at ambient conditions using water, methanol, and acetone as model fluids with varying formulation properties, such as density, …
Subsystem Identification Of Feedback And Feedforward Systems With Time Delay, S. Alireza Seyyed Mousavi, Xingye Zhang, Thomas M. Seigler, Jesse B. Hoagg
Subsystem Identification Of Feedback And Feedforward Systems With Time Delay, S. Alireza Seyyed Mousavi, Xingye Zhang, Thomas M. Seigler, Jesse B. Hoagg
Mechanical Engineering Faculty Publications
We present an algorithm for identifying discrete-time feedback-and-feedforward subsystems with time delay that are interconnected in closed loop with a known subsystem. This frequency-domain algorithm uses only measured input and output data from a closed-loop discrete-time system, which is single input and single output. No internal signals are assumed to be measured. The orders of the unknown feedback and feedforward transfer functions are assumed to be known. We use a two-candidate-pool multi-convex-optimization approach to identify not only the feedback and feedforward transfer functions but also the feedback and feedforward time delay. The algorithm guarantees asymptotic stability of the identified closed-loop …
Laser Powder Bed Fusion Of Nitihf High-Temperature Shape Memory Alloy: Effect Of Process Parameters On The Thermomechanical Behavior, Mohammadreza Nematollahi, Guher P. Toker, Keyvan Safaei, Alejandro Hinojos, S. Ehsan Saghaian, Othmane Benafan, Michael J. Mills, Haluk E. Karaca, Mohammad Elahinia
Laser Powder Bed Fusion Of Nitihf High-Temperature Shape Memory Alloy: Effect Of Process Parameters On The Thermomechanical Behavior, Mohammadreza Nematollahi, Guher P. Toker, Keyvan Safaei, Alejandro Hinojos, S. Ehsan Saghaian, Othmane Benafan, Michael J. Mills, Haluk E. Karaca, Mohammad Elahinia
Mechanical Engineering Faculty Publications
Laser powder bed fusion has been widely investigated for shape memory alloys, primarily NiTi alloys, with the goal of tailoring microstructures and producing complex geometries. However, processing high temperature shape memory alloys (HTSMAs) remains unknown. In our previous study, we showed that it is possible to manufacture NiTiHf HTSMA, as one of the most viable alloys in the aerospace industry, using SLM and investigated the effect of parameters on defect formation. The current study elucidates the effect of process parameters (PPs) on the functionality of this alloy. Shape memory properties and the microstructure of additively manufactured Ni-rich NiTiHf alloys were …
Efficient Trajectory Optimization For Curved Running Using A 3d Musculoskeletal Model With Implicit Dynamics, Marlies Nitschke, Eva Dorschky, Dieter Heinrich, Heiko Schlarb, Bjoern M. Eskofier, Anne D. Koelewijn, Antonie J. Van Den Bogert
Efficient Trajectory Optimization For Curved Running Using A 3d Musculoskeletal Model With Implicit Dynamics, Marlies Nitschke, Eva Dorschky, Dieter Heinrich, Heiko Schlarb, Bjoern M. Eskofier, Anne D. Koelewijn, Antonie J. Van Den Bogert
Mechanical Engineering Faculty Publications
Trajectory optimization with musculoskeletal models can be used to reconstruct measured movements and to predict changes in movements in response to environmental changes. It enables an exhaustive analysis of joint angles, joint moments, ground reaction forces, and muscle forces, among others. However, its application is still limited to simplified problems in two dimensional space or straight motions. The simulation of movements with directional changes, e.g. curved running, requires detailed three dimensional models which lead to a high-dimensional solution space. We
extended a full-body three dimensional musculoskeletal model to be specialized for running with directional changes. Model dynamics were implemented implicitly …
Effect Of Additional Weight On Human Squat Exercise Stability: Ground Reaction Forces And Centers Of Pressure, Jose Galarza, Dumitru Carantu
Effect Of Additional Weight On Human Squat Exercise Stability: Ground Reaction Forces And Centers Of Pressure, Jose Galarza, Dumitru Carantu
Mechanical Engineering Faculty Publications
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. …
Design And Validation Of A Portable Handheld Device To Produce Fine Fibers Using Centrifugal Forces, Gregory Potter, Raul Barbosa, Alexa Villarreal, Alexandra Salinas, Hector Guzman, Heriberto De Leon, Javier A. Ortega, Karen Lozano
Design And Validation Of A Portable Handheld Device To Produce Fine Fibers Using Centrifugal Forces, Gregory Potter, Raul Barbosa, Alexa Villarreal, Alexandra Salinas, Hector Guzman, Heriberto De Leon, Javier A. Ortega, Karen Lozano
Mechanical Engineering Faculty Publications
In the present research project, a novel portable battery-powered handheld device able to produce micron and submicron fibers using centrifugal forces is proposed. The design includes spinnerets with a clamshell configuration with multiple chambers or reservoirs (2, 4, and 8) and different exit orifice diameters (400, 500, 600, and 800 µm). The rotational speed is controlled via an Arduino microcontroller. To validate the design, a series of experiments were conducted and the effect of the orifice diameter, number of chambers, and velocity on the resulting fibers’ diameter and yield was studied. For the experiments, a polymeric solution of Polyvinyl Alcohol …
Elmer Fem-Dakota: A Unified Open-Source Computational Framework For Electromagnetics And Data Analytics, Anjali Sandip
Elmer Fem-Dakota: A Unified Open-Source Computational Framework For Electromagnetics And Data Analytics, Anjali Sandip
Mechanical Engineering Faculty Publications
Open-source electromagnetic design software, Elmer FEM, was interfaced with data analytics toolkit, Dakota. Furthermore, the coupled software was validated against a benchmark test. The interface developed provides a unified open-source computational framework for electromagnetics and data analytics. Its key features include uncertainty quantification, surrogate modelling and parameter studies. This framework enables a richer understanding of model predictions to better design electric machines in a time sensitive manner.
University Of Kentucky Measurements Of Wind, Temperature, Pressure And Humidity In Support Of Lapse-Rate Using Multisite Fixed-Wing And Rotorcraft Unmanned Aerial Systems, Sean C. C. Bailey, Michael P. Sama, Caleb A. Canter, Luis Felipe Pampolini, Zachary S. Lippay, Travis J. Schuyler, Jonathan D. Hamilton, Sean B. Macphee, Isaac S. Rowe, Christopher D. Sanders, Virginia G. Smith, Christina N. Vezzi, Harrison M. Wight, Jesse B. Hoagg, Marcelo I. Guzman, Suzanne Weaver Smith
University Of Kentucky Measurements Of Wind, Temperature, Pressure And Humidity In Support Of Lapse-Rate Using Multisite Fixed-Wing And Rotorcraft Unmanned Aerial Systems, Sean C. C. Bailey, Michael P. Sama, Caleb A. Canter, Luis Felipe Pampolini, Zachary S. Lippay, Travis J. Schuyler, Jonathan D. Hamilton, Sean B. Macphee, Isaac S. Rowe, Christopher D. Sanders, Virginia G. Smith, Christina N. Vezzi, Harrison M. Wight, Jesse B. Hoagg, Marcelo I. Guzman, Suzanne Weaver Smith
Mechanical Engineering Faculty Publications
In July 2018, unmanned aerial systems (UASs) were deployed to measure the properties of the lower atmosphere within the San Luis Valley, an elevated valley in Colorado, USA, as part of the Lower Atmospheric Profiling Studies at Elevation – a Remotely-piloted Aircraft Team Experiment (LAPSE-RATE). Measurement objectives included detailing boundary layer transition, canyon cold-air drainage and convection initiation within the valley. Details of the contribution to LAPSE-RATE made by the University of Kentucky are provided here, which include measurements by seven different fixed-wing and rotorcraft UASs totaling over 178 flights with validated data. The data from these coordinated UAS flights …
Optimizing Power Consumption Of Freight Railroad Bearings Using Laboratory Experimental Data, Carlos E. Lopez Iii, Constantine Tarawneh, Arturo A. Fuentes, Harry Siegal
Optimizing Power Consumption Of Freight Railroad Bearings Using Laboratory Experimental Data, Carlos E. Lopez Iii, Constantine Tarawneh, Arturo A. Fuentes, Harry Siegal
Mechanical Engineering Faculty Publications
Based on projected freight truck fuel efficiency, freight railroad and equipment suppliers need to identify, evaluate and implement technologies and/or operating practices to maintain traditional railroad economic competitiveness. The railway industry uses systems that record the total energy efficiency of a train but not energy efficiency or consumption by components. Lowering the energy consumption of certain train components will result in an increase in its overall energy efficiency, which will yield cost benefits for all the stakeholders. One component of interest is the railroad bearing whose power consumption varies depending on several factors that include railcar load, train speed, condition …
Estimating The Inner Ring Defect Size And Residual Service Life Of Freight Railcar Bearings Using Vibration Signatures, Jennifer Lima, Constantine Tarawneh, Jesse Aguilera, Jonas Cuanang
Estimating The Inner Ring Defect Size And Residual Service Life Of Freight Railcar Bearings Using Vibration Signatures, Jennifer Lima, Constantine Tarawneh, Jesse Aguilera, Jonas Cuanang
Mechanical Engineering Faculty Publications
There are currently two primary wayside detection systems for monitoring the health of freight railcar bearings in the railroad industry: The Trackside Acoustic Detection System (TADS™) and the wayside Hot-Box Detector (HBD). TADS™ uses wayside microphones to detect and alert the train operator of high-risk defects. However, many defective bearings may never be detected by TADS™ since a high-risk defect is a spall which spans about 90% of a bearing’s raceway, and there are less than 30 systems in operation throughout the United States and Canada. HBDs sit on the side of the rail-tracks and use non-contact infrared sensors to …
An Iterative Size Effect Model Of Surface Generation In Finish Machining, Ian S. Brown, Julius M. Schoop
An Iterative Size Effect Model Of Surface Generation In Finish Machining, Ian S. Brown, Julius M. Schoop
Mechanical Engineering Faculty Publications
In this work, a geometric model for surface generation of finish machining was developed in MATLAB, and subsequently verified by experimental surface roughness data gathered from turning tests in Ti-6Al4V. The present model predicts the behavior of surface roughness at multiple length scales, depending on feed, nose radius, tool edge radius, machine tool error, and material-dependent parameters—in particular, the minimum effective rake angle. Experimental tests were conducted on a commercial lathe with slightly modified conventional tooling to provide relevant results. Additionally, the model-predicted roughness was compared against pedigreed surface roughness data from previous efforts that included materials 51CrV4 and AL …
Casimir Effect On Amplitude-Frequency Response Of Parametric Resonance Of Electrostatically Actuated Nems Cantilever Resonators, Dumitru Caruntu, Christian A. Reyes
Casimir Effect On Amplitude-Frequency Response Of Parametric Resonance Of Electrostatically Actuated Nems Cantilever Resonators, Dumitru Caruntu, Christian A. Reyes
Mechanical Engineering Faculty Publications
This paper deals with the effect of Casimir force on the amplitudefrequency response of parametric resonance of electrostatically actuated nanoresonators. The resonator is actuated by using an electrostatic force to include a f irst order fringe correction. Casimir force and viscous damping force are included in the model, as well. Both electrostatic and Casimir forces are nonlinear. The behavior of the resonator is investigated using two methods, the Method of Multiple Scales (MMS) for a Reduced Order Model (ROM) using one mode of vibration, and numerical integration of ROMs using up to five modes of vibration. ROM is based on …
Optimization Of Railroad Bearing Health Monitoring System For Wireless Utilization, Jonas Cuanang, Constantine Tarawneh, Martin Amaro Jr., Jennifer Lima, Heinrich D. Foltz
Optimization Of Railroad Bearing Health Monitoring System For Wireless Utilization, Jonas Cuanang, Constantine Tarawneh, Martin Amaro Jr., Jennifer Lima, Heinrich D. Foltz
Mechanical Engineering Faculty Publications
In the railroad industry, systematic health inspections of freight railcar bearings are required. Bearings are subjected to high loads and run at high speeds, so over time the bearings may develop a defect that can potentially cause a derailment if left in service operation. Current bearing condition monitoring systems include Hot-Box Detectors (HBDs) and Trackside Acoustic Detection Systems (TADS™). The commonly used HBDs use non-contact infrared sensors to detect abnormal temperatures of bearings as they pass over the detector. Bearing temperatures that are about 94°C above ambient conditions will trigger an alarm indicating that the bearing must be removed from …
Processing-Structure-Property Relationships Of Biopolyester/Zinc Oxide Fibrous Scaffolds Engineered By Centrifugal Spinning, Victoria Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Antonio Ledezma-Pérez, Carmen Alvarado-Canché, Cristobal Rodriguez, Robert Gilkerson, Karen Lozano
Processing-Structure-Property Relationships Of Biopolyester/Zinc Oxide Fibrous Scaffolds Engineered By Centrifugal Spinning, Victoria Padilla-Gainza, Heriberto Rodríguez-Tobías, Graciela Morales, Antonio Ledezma-Pérez, Carmen Alvarado-Canché, Cristobal Rodriguez, Robert Gilkerson, Karen Lozano
Mechanical Engineering Faculty Publications
This study addresses the processing of nonwoven fibrous materials obtained by centrifugal spinning method, namely Forcespinning; a high yield and low production cost technique little explored in this field. Poly(D, L-lactic acid) (PDLLA) and poly(3-hydroxybutyrate) (PHB) were used as matrices and reinforced with zinc oxide nanoparticles (n-ZnO). The morphology, mechanical, and thermal performance of the developed composites were analyzed as well as the antibacterial effect of n-ZnO. Fibrous materials with n-ZnO concentrations of 1, 3, and 5 wt. % for PDLLA and 1 and 3 wt. % for PHB were evaluated. The results showed that the incorporation of n-ZnO produces …
Characterization And Modeling Of Surface Roughness And Burr Formation In Slot Milling Of Polycarbonate, David Adeniji, Julius M. Schoop, Shehan Gunawardena, Craig Hanson, Muhammad Jahan
Characterization And Modeling Of Surface Roughness And Burr Formation In Slot Milling Of Polycarbonate, David Adeniji, Julius M. Schoop, Shehan Gunawardena, Craig Hanson, Muhammad Jahan
Mechanical Engineering Faculty Publications
Thermoplastic materials hold great promise for next-generation engineered and sustainable plastics and composites. However, due to their thermoplastic nature and viscoplastic material response, it is difficult to predict the properties of surfaces generated by machining. This is especially problematic in micro-channel machining, where burr formation and excessive surface roughness lead to poor component-surface integrity. This study attempts to model the influence of size effects, which occur due to the finite sharpness of any cutting tool, on surface finish and burr formation during micro-milling of an important thermoplastic material, polycarbonate. Experimental results show that the depth of cut does not affect …