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Articles 1 - 30 of 856
Full-Text Articles in Engineering
Heat Treatment Post-Processing For The Improved Mechanical Properties Of Scalmalloy® Processed Via Directed Energy Deposition, Rachel Boillat-Newport, Sriram Praneeth Isanaka, Frank Liou
Heat Treatment Post-Processing For The Improved Mechanical Properties Of Scalmalloy® Processed Via Directed Energy Deposition, Rachel Boillat-Newport, Sriram Praneeth Isanaka, Frank Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
As high-strength aluminum alloys present several processability issues with additive manufacturing (AM), Scalmalloy®, an Al-Mg-Sc-Zr-based alloy, has been developed. This alloy is age-hardenable, allowing it to precipitate out a strengthening precipitate phase, Al3(Sc,Zr). The manufacturer recommends a single-stage aging treatment at 325 °C for 4 h; however, the majority of the literature studies utilize a powder bed processing known as selective laser melting (SLM) over powder-fed processing directed energy deposition (DED). This study addresses the lack of information on heat treatments for DED fabrication by exploring the application of artificial aging temperatures of 300–400 °C for 2, 4, and 6 …
Modeling Powder Spreadability In Powder-Based Processes Using The Discrete Element Method, Austin T. Sutton, M. Hossein Sehhat, Ming C. Leu, Joseph W. Newkirk
Modeling Powder Spreadability In Powder-Based Processes Using The Discrete Element Method, Austin T. Sutton, M. Hossein Sehhat, Ming C. Leu, Joseph W. Newkirk
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Powder-bed fusion (PBF) processes refer to a subset of Additive Manufacturing (AM) techniques where powder is spread on the build-plate before melting (by a laser or electron beam). While PBF processes are attractive due to their ability for realizing complex structures that are either difficult or impossible to create through conventional means, the parts fabricated with these techniques can exhibit defects such as pores, inclusions, and excessive surface roughness. To minimize these defects, much research has been dedicated towards process maturation by optimizing laser or electron beam parameters. However, these developmental efforts typically do not address the recoating process where …
A Study Of Directionality Effects In Three-Beam Coaxial Titanium Wire-Based Laser Metal Deposition, Remy Mathenia, Braden Mclain, Todd Sparks, Frank Liou
A Study Of Directionality Effects In Three-Beam Coaxial Titanium Wire-Based Laser Metal Deposition, Remy Mathenia, Braden Mclain, Todd Sparks, Frank Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Coaxial wire-based laser metal deposition is a versatile and efficient additive process that can achieve a high deposition rate in the manufacturing of complex structures. In this paper, a three-beam coaxial wire system is studied, with particular attention given to the effects of the deposition direction and laser beam orientation on the resulting bead geometry symmetry. With the three-beam laser delivery, the laser spot pattern is not always symmetric with respect to the deposition direction. Single titanium beads are deposited in different directions and at varying deposition rates, and the bead profile is quantitatively scored for multiple symmetry measures. Through …
Analytical And Fem Models For Thermal Analysis And Residual Stresses Using Wire Arc-Based Welding And Additive Manufacturing Of Sus304, Muhammad Arif Mahmood, Usman Tariq, Mihai Oane, Frank Liou
Analytical And Fem Models For Thermal Analysis And Residual Stresses Using Wire Arc-Based Welding And Additive Manufacturing Of Sus304, Muhammad Arif Mahmood, Usman Tariq, Mihai Oane, Frank Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Austenitic stainless steel, also known as SUS304, has a wide industrial application. The resultant residual stresses and deformation due to arc welding play a critical role in an in-service SUS04 part failure. Various experimental studies have been presented to predict residual stresses and part deformation. However, these techniques are expensive and time-consuming owing to the trial-and-error approach, limiting their application to industrial applications. Based on the emergent need, this study introduces two simulation models based on analytical and FEM techniques for thermal distribution and residual stress estimation. The experimentally calibrated models results have been implemented for SUS304 multi-pass arc welding. …
Infrared Phase-Change Chiral Metasurfaces With Tunable Circular Dichroism, Haotian Tang, Liliana Stan, David A. Czaplewski, Xiaodong Yang, Jie Gao
Infrared Phase-Change Chiral Metasurfaces With Tunable Circular Dichroism, Haotian Tang, Liliana Stan, David A. Czaplewski, Xiaodong Yang, Jie Gao
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Integrating Phase-Change Materials in Meta surfaces Has Emerged as a Powerful Strategy to Realize Optical Devices with Tunable Electromagnetic Responses. Here, Phase-Change Chiral Meta surfaces based on GST-225 Material with the Designed Trapezoid-Shaped Resonators Are Demonstrated to Achieve Tunable Circular Dichroism (CD) Responses in the Infrared Regime. the Asymmetric Trapezoid-Shaped Resonators Are Designed to Support Two Chiral Plasmonic Resonances with OppositeCDresponses for Realizing SwitchableCDbetween Negative and Positive Values using the GST Phase Change from Amorphous to Crystalline. the Electromagnetic Field Distributions of the Chiral Plasmonic Resonant Modes Are Analyzed to Understand the Chiroptical Responses of the Meta surface. Furthermore, the …
Transfer-Learning-Enhanced Regression Generative Adversarial Networks For Optimal Evtol Takeoff Trajectory Prediction, Shuan Tai Yeh, Xiaosong Du
Transfer-Learning-Enhanced Regression Generative Adversarial Networks For Optimal Evtol Takeoff Trajectory Prediction, Shuan Tai Yeh, Xiaosong Du
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Electric vertical takeoff and landing (eVTOL) aircraft represent a crucial aviation technology to transform future transportation systems. The unique characteristics of eVTOL aircraft include reduced noise, low pollutant emission, efficient operating cost, and flexible maneuverability, which in the meantime pose critical challenges to advanced power retention techniques. Thus, optimal takeoff trajectory design is essential due to immense power demands during eVTOL takeoffs. Conventional design optimizations, however, adopt high-fidelity simulation models in an iterative manner resulting in a computationally intensive mechanism. In this work, we implement a surrogate-enabled inverse mapping optimization architecture, i.e., directly predicting optimal designs from design requirements (including …
Effects Of Process-Induced Defects On The Corrosion Of Additively Manufactured Stainless Steel 304l, Leila Saberi, Frank W. Liou, Mehdi Amiri
Effects Of Process-Induced Defects On The Corrosion Of Additively Manufactured Stainless Steel 304l, Leila Saberi, Frank W. Liou, Mehdi Amiri
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This Study Investigates the Impact of Process-Induced Defects Such as Gas Pores, Lack of Fusions, and Surface Roughness on Corrosion Behavior of Stainless Steel 304L (SS304L) Fabricated by Laser Powder Bed Fusion Additive Manufacturing. Specimens Are Printed with Optimized Process Parameters but Selected from Different Locations on the Build Plate. Parallel and Perpendicular Surfaces to the Build Direction Are Investigated and Compared with Corrosion Properties of Wrought SS304L in 5 Wt% NaCl. the Results Reveal Significant Difference in Corrosion Behavior among Specimens Due to Variations in their Defect Features. Pitting Potential, Pit Initiation, and Growth Rates Are Found to Be …
Effect Of Pre-Heating On Residual Stresses And Deformation In Laser-Based Directed Energy Deposition Repair: A Comparative Analysis, Usman Tariq, Sung Heng Wu, Muhammad Arif Mahmood, Michael M. Woodworth, Frank W. Liou
Effect Of Pre-Heating On Residual Stresses And Deformation In Laser-Based Directed Energy Deposition Repair: A Comparative Analysis, Usman Tariq, Sung Heng Wu, Muhammad Arif Mahmood, Michael M. Woodworth, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Laser-Directed Energy Deposition (DED), a Metal Additive Manufacturing Method, is Renowned for its Role in Repairing Parts, Particularly When Replacement Costs Are Prohibitive. Ensuring that Repaired Parts Avoid Residual Stresses and Deformation is Crucial for Maintaining Functional Integrity. This Study Conducts Experimental and Numerical Analyses on Trapezoidal Shape Repairs, Validating Both the Thermal and Mechanical Models with Experimental Results. Additionally, the Study Presents a Methodology for Creating a Toolpath Applicable to Both the DED Process and Abaqus CAE Software. the Findings Indicate that Employing a Pre-Heating Strategy Can Reduce Residual Stresses by over 70% Compared to No Pre-Heating. However, Pre-Heating …
Uncertainty Quantification Of Thermal Capacitance Calorimeter For High-Enthalpy Flows, Logan Banker, Davide Vigano
Uncertainty Quantification Of Thermal Capacitance Calorimeter For High-Enthalpy Flows, Logan Banker, Davide Vigano
Undergraduate Research Conference at Missouri S&T
Thermal capacitance calorimeters are the standard instrument used to measure cold wall heat fluxes in high-enthalpy flows that simulates hypersonic flight conditions. These instruments play a fundamental role in the development and testing of Thermal Protection Systems for space re-entry conditions. However, despite their rugged and simple design, they are affected by large uncertainty errors. These have been estimated in literature at 15%. Despite their importance, and large errors, no proper uncertainty analysis has been performed. Uncertainty analysis is difficult due to the complex physics of the environment these calorimeters have to operate into.
Supersonic Wind Tunnel Modeling, Noah Cain, Davide Vigano
Supersonic Wind Tunnel Modeling, Noah Cain, Davide Vigano
Undergraduate Research Conference at Missouri S&T
Supersonic wind tunnels are essential for high-speed aerodynamics research, allowing studies ranging from fundamental flow physics to the advancement of supersonic transport. This work presents a physics-based model developed for the Missouri S& T supersonic wind tunnel, a blow-down facility employing a converging-diverging nozzle to achieve high-speed flow. The model accounts for real gas effects, including Joule-Thomson phenomena, as well as predictions of pressure losses and heat transfer. Implemented in Matlab, the model's accuracy was validated through comparison with experimental measurements, demonstrating excellent agreement. This research contributes to the reliable prediction of supersonic wind tunnel performance, thus advancing the understanding …
Using Efficient Global Optimization With Cfd For Aerodynamic Optimization, Aaron Spillars, Nathan Roberts, Xiaoping Du
Using Efficient Global Optimization With Cfd For Aerodynamic Optimization, Aaron Spillars, Nathan Roberts, Xiaoping Du
Undergraduate Research Conference at Missouri S&T
Machine learning and optimization are the stepping blocks in broad engineering areas, such as computational fluid dynamics (CFO) and CFO-based design optimization. Using the CFO-based optimization framework, MACH-Aero, we were able to use the SLSQP optimizer and compared the results with a reference case completed by the SNOPT optimizer. Results verified that our SLSQP optimizer was working properly. The solver created showed that our objective function had a difference in magnitude of 0.000019 allowing us to conclude that our solver was working as intended. However, there were several failed attempts before reaching a successful run that gave us a satisfactory …
Organic Contaminant Effects On The Mac Of Water, Jordan Hartfield
Organic Contaminant Effects On The Mac Of Water, Jordan Hartfield
Undergraduate Research Conference at Missouri S&T
The evaporation or condensation rate of a liquid surface is directly proportional to the mass accommodation coefficient (MAC). Since the MAC is difficult, if not impossible, to experimentally measure, molecular dynamics (MD) simulations have been employed to study it. Experimental studies have shown that airborne hydrocarbon contaminants from a variety of sources can adsorb on liquid surfaces and significantly alter the surface properties. We have therefore studied the effects of organic surface contaminants, which are immiscible with water, on the MAC using equilibrium and nonequilibrium MD simulations. Our equilibrium MD simulation results show that the MAC decreases linearly with increases …
Development Of A Force Perturbation Handle For Physical Interaction Research In Humans, Henry Tien, Riley Still, Yun Seong Song
Development Of A Force Perturbation Handle For Physical Interaction Research In Humans, Henry Tien, Riley Still, Yun Seong Song
Undergraduate Research Conference at Missouri S&T
The vision of developing more advanced robots that physically interact with people begins with the study of how people interact with each other. Even the simplest interactions between humans, such as shaking hands, provides tremendous challenges for current robots and minimal research has been conducted on the inner workings of these interactions. Understanding the process and mechanics behind effective and intuitive physical human-human interaction (pHHI) will yield meaningful insight into designing robots capable of assisting the elderly, operating side by side with workers, or even dancing with people. To study this process, a custom Force Perturbation Handle (FPH) was developed, …
New Testing Capabilities Of The Missouri University Of Science And Technology Supersonic Wind Tunnel, Joshua Gary, Davide Vigano
New Testing Capabilities Of The Missouri University Of Science And Technology Supersonic Wind Tunnel, Joshua Gary, Davide Vigano
Undergraduate Research Conference at Missouri S&T
The development of non-intrusive, laser-based diagnostic techniques has significantly enhanced supersonic experimental aerodynamics, enabling the measurement of many parameters in complex flow fields. Among these techniques, Tomographic Particle Image Velocimetry, capable of measuring 3 components of velocity in 3-dimensional volumes, is now available at the Aerodynamics Research Laboratory of the Missouri University of Science and Technology. To integrate this new system into the university's supersonic wind tunnel, a redesigned nozzle, test section, and diffuser have been implemented. The upgraded modular test section features 4 large ports which can be configured with windows for optical diagnostics or lead plates for model …
Density Fluctuations Measurements In Supersonic Flows, Allie Dingfield, Davide Vigano
Density Fluctuations Measurements In Supersonic Flows, Allie Dingfield, Davide Vigano
Undergraduate Research Conference at Missouri S&T
Turbulence in compressible flows plays a major role in a variety of aerospace applications. However, due to fluctuating thermodynamic quantities, compressible turbulence is challenging to analyze. Of these quantities, density fluctuations are of high importance due to their role in describing turbulence. A method to obtain quantitative measurements of density fluctuations has been developed using the optical technique of shadowgraph imaging. Shadowgraph imaging has frequently been used to obtain qualitative information about density gradients in fluids. However, quantitative application of these methods is much less common. The quantitative shadowgraph method presented here relates the light intensity variations in an image …
Fea Analysis On S& T Student Designed Satellite, Joseph Nguyen
Fea Analysis On S& T Student Designed Satellite, Joseph Nguyen
Undergraduate Research Conference at Missouri S&T
The Missouri Rolla and Missouri Rolla Second Satellite (MR & MRS) is a paired satellite developed by the Missouri S& T Satellite Reseach Team (M-SAT) designed to test new technologies in support of missions involving proximity operations. The M-SAT team won first place in the Nanosatellite Competition hosted by Air Force Research Laboratory in 2015 and obtained funding to proceed with design development. The MR & MRS satellite today will undergo extensive revisions to meet new design requirements and changing technological advancements. The alterations planned for MR & MRS will not only change the structure but directly affect the thermal …
Convolutional Spiking Neural Networks For Intent Detection Based On Anticipatory Brain Potentials Using Electroencephalogram, Nathan Lutes, V. Sriram Siddhardh Nadendla, K. Krishnamurthy
Convolutional Spiking Neural Networks For Intent Detection Based On Anticipatory Brain Potentials Using Electroencephalogram, Nathan Lutes, V. Sriram Siddhardh Nadendla, K. Krishnamurthy
Computer Science Faculty Research & Creative Works
Spiking neural networks (SNNs) are receiving increased attention because they mimic synaptic connections in biological systems and produce spike trains, which can be approximated by binary values for computational efficiency. Recently, the addition of convolutional layers to combine the feature extraction power of convolutional networks with the computational efficiency of SNNs has been introduced. This paper studies the feasibility of using a convolutional spiking neural network (CSNN) to detect anticipatory slow cortical potentials (SCPs) related to braking intention in human participants using an electroencephalogram (EEG). Data was collected during an experiment wherein participants operated a remote-controlled vehicle on a testbed …
Experimental, Computational, And Machine Learning Methods For Prediction Of Residual Stresses In Laser Additive Manufacturing: A Critical Review, Sung Heng Wu, Usman Tariq, Ranjit Joy, Todd Sparks, Aaron Flood, Frank W. Liou
Experimental, Computational, And Machine Learning Methods For Prediction Of Residual Stresses In Laser Additive Manufacturing: A Critical Review, Sung Heng Wu, Usman Tariq, Ranjit Joy, Todd Sparks, Aaron Flood, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In recent decades, laser additive manufacturing has seen rapid development and has been applied to various fields, including the aerospace, automotive, and biomedical industries. However, the residual stresses that form during the manufacturing process can lead to defects in the printed parts, such as distortion and cracking. Therefore, accurately predicting residual stresses is crucial for preventing part failure and ensuring product quality. This critical review covers the fundamental aspects and formation mechanisms of residual stresses. It also extensively discusses the prediction of residual stresses utilizing experimental, computational, and machine learning methods. Finally, the review addresses the challenges and future directions …
Insight Into Uniform Filming Of Lif-Rich Interphase Via Synergistic Adsorption For High-Performance Lithium Metal Anode, Yufang He, Li Wang, Aiping Wang, Bo Zhang, Hiep Pham, Jonghyun Park, Xiangming He
Insight Into Uniform Filming Of Lif-Rich Interphase Via Synergistic Adsorption For High-Performance Lithium Metal Anode, Yufang He, Li Wang, Aiping Wang, Bo Zhang, Hiep Pham, Jonghyun Park, Xiangming He
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Multi-scale simulation is an important basis for constructing digital batteries to improve battery design and application. Lif-rich solid electrolyte interphase (sei) is experimentally proven to be crucial for the electrochemical performance of lithium metal batteries. However, the lif-rich sei is sensitive to various electrolyte formulas and the fundamental mechanism is still unclear. Herein, the structure and formation mechanism of lif-rich sei in different electrolyte formulas have been reviewed. On this basis, it further discussed the possible filming mechanism of lif-rich sei determined by the initial adsorption of the electrolyte-derived species on the lithium metal anode (lma). It proposed that individual …
Jet-Driven Mixing Regimes Identified In The Unsteady Isothermal Filling Of Rectangular Municipal Water Storage Tanks, Pramod Narayan Bangalore, K. (Kelly) O. Homan
Jet-Driven Mixing Regimes Identified In The Unsteady Isothermal Filling Of Rectangular Municipal Water Storage Tanks, Pramod Narayan Bangalore, K. (Kelly) O. Homan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Poor mixing of old and new water in municipal water storage vessels is a well-documented basis for potentially harmful water quality degradation in drinking water distribution systems. This numerical study investigates the effects of inflow and operational variables on mixing in the jet-driven filling process, with a particular focus on the transition from inadequate to sufficient mixing levels. An isothermal unsteady reynolds-averaged-navier-stokes volume-of-fluid (RANS-VOF) simulation is used to model the variable-volume filling process, accounting for the moving free surface following a draw-down in the stored water volume. A low diffusivity tracer is used to mark the old-water volume, and a …
Heat Treatments For Minimization Of Residual Stresses And Maximization Of Tensile Strengths Of Scalmalloy® Processed Via Directed Energy Deposition, Rachel Boillat-Newport, Sriram Praneeth Isanaka, Jonathan Kelley, Frank Liou
Heat Treatments For Minimization Of Residual Stresses And Maximization Of Tensile Strengths Of Scalmalloy® Processed Via Directed Energy Deposition, Rachel Boillat-Newport, Sriram Praneeth Isanaka, Jonathan Kelley, Frank Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Scalmalloy® is an Al-Mg-Sc-Zr-Based Alloy Specifically Developed for Additive Manufacturing (AM). This Alloy is Designed for Use with a Direct Aging Treatment, as Recommended by the Manufacturer, Rather Than with a Multistep Treatment, as Often Seen in Conventional Manufacturing. Most Work with Scalmalloy® is Conducted using Powder Bed Rather Than Powder-Fed Processes. This Investigation Seeks to Fill This Knowledge Gap and Expand Beyond Single-Step Aging to Promote an overall Balanced AM-Fabricated Component. for This Study, Directed Energy Deposition (DED)-Fabricated Scalmalloy® Components Were Subjected to Low-Temperature Treatments to Minimize Residual Stresses Inherent in the Material Due to the Layer-By-Layer Build Process. …
Optimal Abort Guidance And Experimental Verification Based On Feature Learning, Vinay Kenny, Sixiong You, Chaoying Pei, Godfrey Hendrix, Roha Gul, Ran Dai, Jeremy Rea
Optimal Abort Guidance And Experimental Verification Based On Feature Learning, Vinay Kenny, Sixiong You, Chaoying Pei, Godfrey Hendrix, Roha Gul, Ran Dai, Jeremy Rea
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The abort mission refers to the mission where the landing vehicle needs to terminate the landing mission when an anomaly happens and be safely guided to the desired orbit. This paper focuses on solving the time-optimal abort guidance (TOAG) problem in real-time via the feature-based learning method. First, according to the optimal control theory, the features are identified to represent the optimal solutions of TOAG using a few parameters. After that, a sufficiently large data set of time-optimal abort trajectories is generated offline by solving the TOAG problems with different initial conditions. Then, the features are extracted for all generated …
Mission-Driven Inverse Design Of Blended Wing Body Aircraft With Machine Learning, Rohan S. Sharma, Serhat Hosder
Mission-Driven Inverse Design Of Blended Wing Body Aircraft With Machine Learning, Rohan S. Sharma, Serhat Hosder
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The intent of this work was to investigate the feasibility of developing machine learning models for calculating values of airplane configuration design variables when provided time-series, mission-informed performance data. Shallow artificial neural networks were developed, trained, and tested using data pertaining to the blended wing body (BWB) class of aerospace vehicles. Configuration design parameters were varied using a Latin-hypercube sampling scheme. These data were used by a parametric-based BWB configuration generator to create unique BWBs. Performance for each configuration was obtained via a performance estimation tool. Training and testing of neural networks were conducted using a K-fold cross-validation scheme. A …
Effects Of Laser Defocusing On Bead Geometry In Coaxial Titanium Wire-Based Laser Metal Deposition, Remy Mathenia, Aaron Flood, Braden Mclain, Todd Sparks, Frank W. Liou
Effects Of Laser Defocusing On Bead Geometry In Coaxial Titanium Wire-Based Laser Metal Deposition, Remy Mathenia, Aaron Flood, Braden Mclain, Todd Sparks, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Coaxial wire-based laser metal deposition is a versatile and efficient additive process that can achieve a high deposition rate in the manufacturing of complex structures. In this paper, a three-beam coaxial wire system is studied, with particular attention to the effects of deposition height and laser defocusing on the resulting bead geometry. As the deposition standoff distance changes, so does the workpiece illumination proportion, which describes the ratio of energy going directly into the feedstock wire and into the substrate. Single titanium beads are deposited at varying defocus levels and deposition rates and the bead aspect ratio is measured and …
Upconversion Photoluminescence Of Monolayer Wse2 With Biaxial Strain Tuning, Shrawan Roy, Jie Gao, Xiaodong Yang
Upconversion Photoluminescence Of Monolayer Wse2 With Biaxial Strain Tuning, Shrawan Roy, Jie Gao, Xiaodong Yang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Mechanical strain can be used to tune the optical properties of monolayer transition metal dichalcogenides (1L-TMDs). Here, up conversion photoluminescence (UPL) from 1L-WSe2 flakes is tuned with biaxial strain induced by cruciform bending and indentation method. It is found that the peak position of UPL is redshifted by around 24 nm as the applied biaxial strain increases from 0% to 0.51%. At the same time, the UPL intensity increases exponentially for the up-conversion energy difference that lies within a broad range between −157 meV to −37 meV. The observed linear and sublinear power dependence of UPL emission in 1L-WSe …
Effects Of Organic Surface Contamination On The Mass Accommodation Coefficient Of Water: A Molecular Dynamics Study, Jordan Hartfield, Eric Bird, Zhi Liang
Effects Of Organic Surface Contamination On The Mass Accommodation Coefficient Of Water: A Molecular Dynamics Study, Jordan Hartfield, Eric Bird, Zhi Liang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The mass accommodation coefficient (MAC), a parameter that quantifies the possibility of a phase change to occur at a liquid-vapor interface, can strongly affect the evaporation and condensation rates at a liquid surface. Due to the various challenges in experimental determination of the MAC, molecular dynamics (MD) simulations have been widely used to study the MAC on liquid surfaces with no impurities or contaminations. However, experimental studies show that airborne hydrocarbons from various sources can adsorb on liquid surfaces and alter the liquid surface properties. In this work, therefore, we study the effects of organic surface contamination, which is immiscible …
Oxidation Of Additively Manufactured Zrb2–Sic In Air And In Co2 At 700–1000 °C, Marharyta Lakusta, Nicholas M. Timme, Abid H. Rafi, Jeremy Lee Watts, M. (Ming) C. (Chuan) Leu, Gregory E. Hilmas, William G. Fahrenholtz, David W. Lipke
Oxidation Of Additively Manufactured Zrb2–Sic In Air And In Co2 At 700–1000 °C, Marharyta Lakusta, Nicholas M. Timme, Abid H. Rafi, Jeremy Lee Watts, M. (Ming) C. (Chuan) Leu, Gregory E. Hilmas, William G. Fahrenholtz, David W. Lipke
Materials Science and Engineering Faculty Research & Creative Works
Oxidation behavior of additively manufactured zrb2–sic in air and in co2 is reported in the temperature range of 700–1000 °c. Observed scale morphologies in air and in co2 were similar, featuring an outer borosilicate layer and an inner porous zirconia layer containing partially oxidized silicon carbide particles and remnant borosilicate products. Oxide scale thicknesses and parabolic scaling constants in air were approximately twice those observed in co2 across all studied temperatures. Activation energies for oxidation of 140 ± 20 kj/mol in air and 110 ± 20 kj/mol in co2 were determined, indicating similar diffusion processes that appear to be rate-limiting. …
Sensor Tasking Strategies For Space-Based Observers In The Cislunar Environment, Smriti Nandan Paul, Roshan Thomas Eapen, Puneet Singla
Sensor Tasking Strategies For Space-Based Observers In The Cislunar Environment, Smriti Nandan Paul, Roshan Thomas Eapen, Puneet Singla
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The cislunar space environment has witnessed an increase in activities, and future projections indicate significant growth in object population. Consequently, it becomes crucial to monitor these objects for space domain awareness (SDA) purposes. As the number of objects surpasses the available observers, meticulous sensor tasking becomes essential. This paper focuses on designing and exploring strategies for observing and keeping custody of known objects in cislunar space. Optical space-based telescopes, combined with lunar ground-based telescope, are employed for sensor tasking of cislunar objects residing in valuable orbits. The proposed research aims to address the following key points: (1) examination of the …
New Testing Capabilities Of The Missouri University Of Science And Technology Supersonic Wind Tunnel, Joshua Gary, Davide Viganò
New Testing Capabilities Of The Missouri University Of Science And Technology Supersonic Wind Tunnel, Joshua Gary, Davide Viganò
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The development of non-intrusive, laser-based diagnostic techniques has significantly enhanced supersonic experimental aerodynamics, enabling the measurement of many parameters in complex flow fields. Among these techniques, Tomographic Particle Image Velocimetry, capable of measuring 3 components of velocity in 3-dimensional volumes, is now available at the Aerodynamics Research Laboratory of the Missouri University of Science and Technology. To integrate this new system into the university's supersonic wind tunnel, a redesigned nozzle, test section, and diffuser have been implemented. The upgraded modular test section features 4 large ports which can be configured with windows for optical diagnostics or lead plates for model …
A Review Of Dielectric Barrier Discharge Cold Atmospheric Plasma For Surface Sterilization And Decontamination, Kolawole Adesina, Ta Chun Lin, Yue-Wern Huang, Marek Locmelis, Daoru Frank Han
A Review Of Dielectric Barrier Discharge Cold Atmospheric Plasma For Surface Sterilization And Decontamination, Kolawole Adesina, Ta Chun Lin, Yue-Wern Huang, Marek Locmelis, Daoru Frank Han
Biological Sciences Faculty Research & Creative Works
Numerous investigations have shown that non-equilibrium discharges at atmospheric pressure, also known as "cold atmospheric plasma" (CAP) are efficient to remove biological contaminants from surfaces of a variety of materials. Recently, CAP has quickly advanced as a technique for microbial cleaning, wound healing, and cancer therapy due to the chemical and biologically active radicals it produces, known collectively as reactive oxygen and nitrogen species (RONS). This article reviews studies pertaining to one of the atmospheric plasma sources known as Dielectric Barrier Discharge (DBD) which has been widely used to treat materials with microbes for sterilization, disinfection, and decontamination purposes. To …