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Lagrangian Displacement Field Estimators In Cosmology, Atsuhisa Ota, Hee Jong Seo, Shun Saito, Florian Beutler Jun 2023

Lagrangian Displacement Field Estimators In Cosmology, Atsuhisa Ota, Hee Jong Seo, Shun Saito, Florian Beutler

Physics Faculty Research & Creative Works

The late-time nonlinear Lagrangian displacement field is highly correlated with the initial field, so reconstructing it could enable us to extract primordial cosmological information. Our previous work [A. Ota et al., Phys. Rev. D 104, 123508 (2021)PRVDAQ2470-001010.1103/PhysRevD.104.123508] carefully studied the displacement field reconstructed from the late-time density field using the iterative method proposed by Schmittfull et al. [Phys. Rev. D 96, 023505 (2017)PRVDAQ2470-001010.1103/PhysRevD.96.023505] and found that it does not fully converge to the true, underlying displacement field (e.g., ∼8% offset at k∼0.2 h Mpc-1 at z=0.6). We also constructed the Lagrangian perturbation theory model for the reconstructed field, but the …

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Anderson Localization Of Electromagnetic Waves In Three Dimensions, Alexey Yamilov, Sergey E. Skipetrov, Tyler W. Hughes, Momchil Minkov, Zongfu Yu, Hui Cao Jun 2023

Anderson Localization Of Electromagnetic Waves In Three Dimensions, Alexey Yamilov, Sergey E. Skipetrov, Tyler W. Hughes, Momchil Minkov, Zongfu Yu, Hui Cao

Physics Faculty Research & Creative Works

Anderson localization is a halt of diffusive wave propagation in disordered systems. Despite extensive studies over the past 40 years, Anderson localization of light in three dimensions has remained elusive, leading to the question of its very existence. Recent advances have enabled finite-difference time-domain calculations to be sped up by orders of magnitude, allowing us to conduct brute-force numerical simulations of light transport in fully disordered three-dimensional systems with unprecedented dimension and refractive index difference. We show numerically three-dimensional localization of vector electromagnetic waves in random aggregates of overlapping metallic spheres, in sharp contrast to the absence of localization for …

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Influence Of Support Attachment Pattern On The Out-Of-Plane Buckling Capacity Of Steel Deck, Divyansh R. Kapoor, Brian Bogh, Kara D. Peterman Jun 2023

Influence Of Support Attachment Pattern On The Out-Of-Plane Buckling Capacity Of Steel Deck, Divyansh R. Kapoor, Brian Bogh, Kara D. Peterman

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

Diaphragms (Figure 1) serve as a critical component of a building's lateral force resisting system (LFRS), transferring lateral loads from the façade of the structure to the designated vertical lateral force resisting system. Design guidance for profiled steel diaphragm panels can be found in AISI S310 - 20 (AISI 2020) and SDI DDM04 (Luttrell 2015) and are controlled by connection limit states or buckling limit states. Deck connectivity with the underlying frame can either be fully attached (For example 36/7), i.e. connected through the bottom of each flute, or partially attached (for example 36/5 or 36/4) where not all the …

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A Hybrid Admm For Six-Degree-Of-Freedom Entry Trajectory Optimization Based On Dual Quaternions, Chaoying Pei, Changhuang Wan, Ran Dai, Jeremy R. Rea Jun 2023

A Hybrid Admm For Six-Degree-Of-Freedom Entry Trajectory Optimization Based On Dual Quaternions, Chaoying Pei, Changhuang Wan, Ran Dai, Jeremy R. Rea

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This article investigates the six-degree-of-freedom (6-DoF) entry trajectory optimization problem in a Human-Mars entry, powered descent, and landing mission. During the entry phase, aerodynamic forces are employed to decelerate the vehicle. Instead of being treated as a point mass, both translational and rotational motions of the entry vehicle are considered. Specifically, the 6-DoF rigid body motion of the entry vehicle is modeled using the unit dual quaternion representations to avoid highly nonlinear terms in the flight dynamics expression originally based on the flight-path coordinates. Then, the entry trajectory optimization problem is to minimize the terminal speed subject to dynamical, operational, …

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Time-Domain Shielding Effectiveness Analysis Based On Dgtd Method Accelerated By Local Time-Stepping And Parallel Techniques, Zheng Lang Jia, Huan Huan Zhang, Da Zhi Ding, Lei Zhao, Qiang Ren, Li (Lijun) Jun Jiang Jun 2023

Time-Domain Shielding Effectiveness Analysis Based On Dgtd Method Accelerated By Local Time-Stepping And Parallel Techniques, Zheng Lang Jia, Huan Huan Zhang, Da Zhi Ding, Lei Zhao, Qiang Ren, Li (Lijun) Jun Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

The discontinuous Galerkin time-domain (DGTD) method accelerated by local time-stepping (LTS) and parallel techniques is employed to analyze the time-domain shielding effectiveness (TDSE) of metallic enclosures. The detailed formulations and implementation procedures of the DGTD method and LTS and parallel techniques are introduced. Numerical results validate the correctness of the proposed method. Moreover, the influence of various design parameters of the metallic enclosure, including aperture dimensions, wall thickness, spacing of aperture arrays, etc., on the TDSE are analyzed by the proposed method. Some rules are given for the design of the enclosure with rectangular apertures from the perspective of TDSE. …

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Field Implementation And Performance Of Fiber-Reinforced Low-Shrinkage Concrete For Bridge Deck Construction, Ahmed Abdelrazik, Kamal Khayat Jun 2023

Field Implementation And Performance Of Fiber-Reinforced Low-Shrinkage Concrete For Bridge Deck Construction, Ahmed Abdelrazik, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Paper Reports on the Field Implementation of Fiber-Reinforced Concrete (FRC) Used for Redecking the Two-Span overpass Bridge in Missouri. the Spans Measured 38.4 and 35.05 M in Length. Modeling of the Structural Behavior of the Bridge Replacement Deck Indicated Significantly High Tensile Stresses at Midspan (Up to 45 MPa) Due to the Continuity of the Deck over the Four Precast Main Girders. Redecking of the Bridge and Casting of the Central Diaphragm Were Carried Out Continuously and Necessitated 40 Concrete Truck Deliveries of 252 M3 of FRC. Six Sensor Towers Were Installed in the Bridge Deck to Monitor Variations …

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Generative And Pseudo-Relevant Feedback For Sparse, Dense And Learned Sparse Retrieval, Iain Mackie, Shubham Chatterjee, Jeffrey Dalton May 2023

Generative And Pseudo-Relevant Feedback For Sparse, Dense And Learned Sparse Retrieval, Iain Mackie, Shubham Chatterjee, Jeffrey Dalton

Computer Science Faculty Research & Creative Works

Pseudo-relevance feedback (PRF) is a classical approach to address lexical mismatch by enriching the query using first-pass retrieval. Moreover, recent work on generative-relevance feedback (GRF) shows that query expansion models using text generated from large language models can improve sparse retrieval without depending on first-pass retrieval effectiveness. This work extends GRF to dense and learned sparse retrieval paradigms with experiments over six standard document ranking benchmarks. We find that GRF improves over comparable PRF techniques by around 10% on both precision and recall-oriented measures. Nonetheless, query analysis shows that GRF and PRF have contrasting benefits, with GRF providing external context …

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Fedar+: A Federated Learning Approach To Appliance Recognition With Mislabeled Data In Residential Environments, Ashish Gupta, Hari Prabhat Gupta, Sajal K. Das May 2023

Fedar+: A Federated Learning Approach To Appliance Recognition With Mislabeled Data In Residential Environments, Ashish Gupta, Hari Prabhat Gupta, Sajal K. Das

Computer Science Faculty Research & Creative Works

With the enhancement of people's living standards and the rapid evolution of cyber-physical systems, residential environments are becoming smart and well-connected, causing a significant raise in overall energy consumption. As household appliances are major energy consumers, their accurate recognition becomes crucial to avoid unattended usage and minimize peak-time load on the smart grids, thereby conserving energy and making smart environments more sustainable. Traditionally, an appliance recognition model is trained at a central server (service provider) by collecting electricity consumption data via smart plugs from the clients (consumers), causing a privacy breach. Besides that, the data are susceptible to noisy labels …

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Fedar+: A Federated Learning Approach To Appliance Recognition With Mislabeled Data In Residential Environments, Ashish Gupta, Hari Prabhat Gupta, Sajal K. Das May 2023

Fedar+: A Federated Learning Approach To Appliance Recognition With Mislabeled Data In Residential Environments, Ashish Gupta, Hari Prabhat Gupta, Sajal K. Das

Computer Science Faculty Research & Creative Works

With the enhancement of people's living standards and the rapid evolution of cyber-physical systems, residential environments are becoming smart and well-connected, causing a significant raise in overall energy consumption. as household appliances are major energy consumers, their accurate recognition becomes crucial to avoid unattended usage and minimize peak-time load on the smart grids, thereby conserving energy and making smart environments more sustainable. Traditionally, an appliance recognition model is trained at a central server (service provider) by collecting electricity consumption data via smart plugs from the clients (consumers), causing a privacy breach. Besides that, the data are susceptible to noisy labels …

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Fully Decoupled Energy-Stable Numerical Schemes For Two-Phase Coupled Porous Media And Free Flow With Different Densities And Viscosities, Yali Gao, Xiaoming He, Tao Lin, Yanping Lin May 2023

Fully Decoupled Energy-Stable Numerical Schemes For Two-Phase Coupled Porous Media And Free Flow With Different Densities And Viscosities, Yali Gao, Xiaoming He, Tao Lin, Yanping Lin

Mathematics and Statistics Faculty Research & Creative Works

In this article, we consider a phase field model with different densities and viscosities for the coupled two-phase porous media flow and two-phase free flow, as well as the corresponding numerical simulation. This model consists of three parts: a Cahn-Hilliard-Darcy system with different densities/viscosities describing the porous media flow in matrix, a Cahn-illiard-Navier-Stokes system with different densities/viscosities describing the free fluid in conduit, and seven interface conditions coupling the flows in the matrix and the conduit. Based on the separate Cahn-Hilliard equations in the porous media region and the free flow region, a weak formulation is proposed to incorporate the …

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Predicting The Friction Coefficient Of High-Friction Surface Treatment Application Aggregates Using The Aggregates' Characteristics, Ahmed S. El-Ashwah, Korrenn Broaddus, Magdy Abdelrahman May 2023

Predicting The Friction Coefficient Of High-Friction Surface Treatment Application Aggregates Using The Aggregates' Characteristics, Ahmed S. El-Ashwah, Korrenn Broaddus, Magdy Abdelrahman

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Providing Sufficient Pavement Surface Friction (I.e., Skid Resistance) between Vehicle Tires and Pavement Surface throughout the Pavement Service Life is Considered to Be One of the Main Objectives of Highway Design. Moreover, Vehicle Safety, the Amount of Consumed Fuel, and the Wearing Rate of Vehicle Tires Generally Are Influenced by Pavement Surface Friction. in This Study, a Comprehensive Experimental Testing Program Was Conducted on Different Aggregate Sources, Including Calcined Bauxite and Five Alternative Local Sources, to Assess their Friction Characteristics. the Testing Program Included a British Pendulum Tester (BPT) and a Dynamic Friction Tester (DFT), Which Were Used to Evaluate …

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A Machine Learning Specklegram Wavemeter (Maswave) Based On A Short Section Of Multimode Fiber As The Dispersive Element, Ogbole C. Inalegwu, Rex E. Gerald, Jie Huang May 2023

A Machine Learning Specklegram Wavemeter (Maswave) Based On A Short Section Of Multimode Fiber As The Dispersive Element, Ogbole C. Inalegwu, Rex E. Gerald, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Wavemeters are very important for precise and accurate measurements of both pulses and continuous-wave optical sources. Conventional wavemeters employ gratings, prisms, and other wavelength-sensitive devices in their design. Here, we report a simple and low-cost wavemeter based on a section of multimode fiber (MMF). The concept is to correlate the multimodal interference pattern (i.e., speckle patterns or specklegrams) at the end face of an MMF with the wavelength of the input light source. Through a series of experiments, specklegrams from the end face of an MMF as captured by a CCD camera (acting as a low-cost interrogation unit) were analyzed …

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Repeated Low-Level Blast Exposure Alters Urinary And Serum Metabolites, Austin Sigler, Jiandong Wu, Annalise Pfaff, Olajide Adetunji, Paul Ki-Souk Nam, Donald James, Casey Burton, Honglan Shi May 2023

Repeated Low-Level Blast Exposure Alters Urinary And Serum Metabolites, Austin Sigler, Jiandong Wu, Annalise Pfaff, Olajide Adetunji, Paul Ki-Souk Nam, Donald James, Casey Burton, Honglan Shi

Chemistry Faculty Research & Creative Works

Repeated exposure to low-level blast overpressures can produce biological changes and clinical sequelae that resemble mild traumatic brain injury (TBI). While recent efforts have revealed several protein biomarkers for axonal injury during repetitive blast exposure, this study aims to explore potential small molecule biomarkers of brain injury during repeated blast exposure. This study evaluated a panel of ten small molecule metabolites involved in neurotransmission, oxidative stress, and energy metabolism in the urine and serum of military personnel (n = 27) conducting breacher training with repeated exposure to low-level blasts. The metabolites were analyzed using HPLC—tandem mass spectrometry, and the Wilcoxon …

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Collisional Excitation Of C2h- By H2: New Interaction Potential And Scattering Calculations, Fabien Dumouchel, Ernesto Quintas-Sánchez, Christian Balança, Richard Dawes, François Lique, Nicole Feautrier Apr 2023

Collisional Excitation Of C2h- By H2: New Interaction Potential And Scattering Calculations, Fabien Dumouchel, Ernesto Quintas-Sánchez, Christian Balança, Richard Dawes, François Lique, Nicole Feautrier

Chemistry Faculty Research & Creative Works

Interstellar Anions Play an Important Role in Astrochemistry as Being Tracers of the Physical and Chemical Conditions in Cold Molecular Clouds and Circumstellar Gas. the Local Thermodynamic Equilibrium is Generally Not Fulfilled in Media Where Anions Are Detected and Radiative and Collisional Data Are Required to Model the Observed Lines. the C2H- Anion Has Not Yet Been Detected in the Interstellar Medium; However, Collisional Data Could Be Used for Non-LTE Models that Would Help in Identifying the Most Intense Lines. for This Purpose, We Have Computed the First 4D Potential Energy Surface (PES) of the C2H--H2 Complex using an Explicitly …

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A Unified Two Independent Stress Variable Approach To Moisture-Change-Induced Unsaturated Soil Volume Change, Sandra Houston, Xiong Zhang Apr 2023

A Unified Two Independent Stress Variable Approach To Moisture-Change-Induced Unsaturated Soil Volume Change, Sandra Houston, Xiong Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In 1968, Matyas and Radhakrishna introduced the concept of the state surface, demonstrating that unsaturated soil volume change is dependent on two independent stress state variables, net total stress and suction. For decades the basic theory of unsaturated soils has been known, and a holistic view of the elastoplastic response of unsaturated soils, based on a modified state surface approach (MSSA), makes it clear that a method accounting for independent roles of net total stress and suction is required to quantify volume change of unsaturated soils. Still, reliance on pre-unsaturated-soil-mechanics-era methods persists, particularly within the geotechnical practice community. Unsaturated soil …

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Calibration Of Bbm Parameters Using The Modified State Surface Approach, Xiong Zhang, Beshoy Riad, Eduardo E. Alonso Apr 2023

Calibration Of Bbm Parameters Using The Modified State Surface Approach, Xiong Zhang, Beshoy Riad, Eduardo E. Alonso

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Barcelona Basic Model (BBM) developed by Alonso et al. [1] is the first and the mostwidely used elasto-plastic model for unsaturated soils. The BBM successfully explained many key features of unsaturated soils and received extensive acceptance. However, there is lack of a well-establishedmethod for selecting parameter values for the BBM from laboratory tests, although a variety of methods have been recently developed for calibrating model parameters for the BBM. Concerns still exist on the correctness and robustness of such parameter value selection procedures. The above statements were evidenced by a recent benchmark exercise on selection of parameter values for …

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Safety Performance Of Different Game-Theoretical Models In An Unsupervised Intersection Crossing Scenario, Brady Bateman Apr 2023

Safety Performance Of Different Game-Theoretical Models In An Unsupervised Intersection Crossing Scenario, Brady Bateman

NASA-Missouri Space Grant Consortium

There are several methods for an autonomous vehicle (AV) to determine its behavior. One area of interest is in using game-theoretical models to determine an AV’s behavior. If AV designers know the relationship between the action taken by players and their corresponding reward functions, then the behaviors of all players can be predicted. This allows for the simulation of player vehicles at an unsupervised intersection. An unsupervised intersection is one where there are no stop signs or traffic lights to help the players make decisions. The motivation of this project is to study the safety and efficiency of three different …

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Novel Topological Semimetals: Growth & Characterizing Sm3hfbi5, Patrick Lambdin Apr 2023

Novel Topological Semimetals: Growth & Characterizing Sm3hfbi5, Patrick Lambdin

NASA-Missouri Space Grant Consortium

After dozens of reactions, the Missouri State University Crystal Growth Lab created a likely-topological material, Sm3HfBi5, through flux crystal growth methods. First created experimentally in 2015, Weyl materials are desirable and have garnered much interest due to the materials’ ability to conduct electricity exclusively on their surfaces. This paper discusses methods of selecting and mixing materials to be sealed inside an evacuated or argon-backfilled glass tube which itself is placed inside a furnace kept at high temperatures, as part of a flux growth method, as well as discussing results and difficulties encountered while growing the crystals.

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Computations Of Flow Past A Three-Element 30p30n Airfoil Using Wray-Agarwal One Equation Turbulence Model, Karsten Hendrickson Apr 2023

Computations Of Flow Past A Three-Element 30p30n Airfoil Using Wray-Agarwal One Equation Turbulence Model, Karsten Hendrickson

NASA-Missouri Space Grant Consortium

The predictions of flow phenomenon that occur in high lift systems have proven to be challenging using the Reynolds-Averaged Navier-Stokes (RANS) equations with turbulence models. The complex interactions that occur among different elements of the wing can be difficult for turbulence models to accurately predict. Results from the recently developed Wray-Agarwal (WA) one-equation turbulence model, the frequently used Spalart-Allmaras (SA) and shear stress transport (SST) k-ω turbulence models are compared to experimental results to evaluate each model’s relative accuracy. The quadratic constitutive relation (QCR) is also used to produce results with the SA and WA models. It is shown that …

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Masses And Radii Of Subdwarf B Stars - Sed Fitting Method, Noah Singer Apr 2023

Masses And Radii Of Subdwarf B Stars - Sed Fitting Method, Noah Singer

NASA-Missouri Space Grant Consortium

The goal of this project is to determine masses and radii of hot subdwarf B stars in hopes of connecting these fundamental intrinsic properties to the evolutionary history of such stars. Subdwarf B stars burn helium in their core, serving as interesting physical laboratories, and the abundance of public data, including GAIA parallaxes and archival photometry, can be used to determine stellar characteristics. In this study, observed photometry is compared to synthetic photometry, calculated from a similar-stellaratmosphere model spectrum. This match determines the effective stellar temperature and radius. With an estimate of surface gravity, mass can be determined. Such determinations …

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Multi-Disciplinary Analysis Surrogate Based On Twin-Generator Generative Adversarial Networks For Electric Drone, Samuel Sisk Apr 2023

Multi-Disciplinary Analysis Surrogate Based On Twin-Generator Generative Adversarial Networks For Electric Drone, Samuel Sisk

NASA-Missouri Space Grant Consortium

Multi-Disciplinary Analysis and Optimization (MDAO) plays an important role in the future of aviation, especially relating to Urban Air Mobility (UAM). MDAO for UAM effectively quantifies and maximizes system performance and safety while minimizing cost or consumption. Electric drone takeoff trajectory design aims to minimize energy consumption while fulfilling acceleration and other constraints to keep passengers comfortable. Conventional simulation-based MDAO is computationally expensive due to repeatedly evaluating physics-based models while naïvely constructing machine learning predictive models, also known as surrogate models, do not scale well with large-scale problems due to the “curse of dimensionality”. A twin-generator generative adversarial networks (Twin-GAN) …

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Computational Analysis Of The Hifire-1 Hypersonic Test Model In Ansys Fluent, Aidan Robert Murphy Apr 2023

Computational Analysis Of The Hifire-1 Hypersonic Test Model In Ansys Fluent, Aidan Robert Murphy

NASA-Missouri Space Grant Consortium

The Hypersonic International Flight Research Experimentation (HIFiRE) program explores and advances hypersonic aerospace systems by developing a multitude of test flight geometries and conducting experimental test flights to obtain data for use in validation of computational models and results. This study focuses on computational validation of heat flux, and calculation of static pressure profiles, skin friction coefficient profiles, and flow contours. The flow field studied is for Mach number 7.18 and an angle of attack (α) of 2°. The flow field include many compressible flow features such as an expansion wave at the intersection of the cone and flat cylindrical …

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Compact Steam Generator Numerical Analysis And Mechanics Design, Parker Rockholm, Congshan Mao Apr 2023

Compact Steam Generator Numerical Analysis And Mechanics Design, Parker Rockholm, Congshan Mao

NASA-Missouri Space Grant Consortium

A heat exchanger is a device that is used to transfer heat between two fluids that are at different temperatures and are separated by a solid wall. This system is used in many engineering applications such as air conditions, power production, waste heat recovery and chemical processing. Heat exchangers are commonly classified by their flow arrangement and type of construction. A special and important class of heat exchanger is termed compact heat exchangers, but ‘compact’ does not refer to its size. These heat exchangers are used to achieve higher performance by using very large surface densities (heat transfer surface area …

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Application Of Wray-Agarwal Turbulence Model To Axisymmetric Subsonic And Transonic Flows, Mike Kiely Apr 2023

Application Of Wray-Agarwal Turbulence Model To Axisymmetric Subsonic And Transonic Flows, Mike Kiely

NASA-Missouri Space Grant Consortium

This paper describes the problem setup, implementation, and numerical results obtained with the commercial CFD software ANSYS Fluent to test the accuracy of the one equation Wray-Agarwal (WA) turbulence model in comparison to the commonly used one-equation Spalart-Allmaras (SA) turbulence model by computing two axisymmetric benchmark problems, namely the subsonic flow past an axisymmetric after-body and the transonic flow past Sandia axisymmetric bump. The axisymmetric after-body case features low speed flow in near separation conditions where it was found that the Wray- Agarwal model and the Spalart-Allmaras model produced nearly identical results. The Sandia transonic axisymmetric bump case features a …

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The Impact Of Hyper-Gravity On C. Elegans Populations In A Laboratory Ecosystem, Greta Adams Apr 2023

The Impact Of Hyper-Gravity On C. Elegans Populations In A Laboratory Ecosystem, Greta Adams

NASA-Missouri Space Grant Consortium

Despite the large amount of effort going into biological hypo gravity studies, there is little of the opposite. In past studies hyper-gravity has been shown to have a huge impact on both the cellular and organismal level of functionality. In this study hyper-gravity was simulated with centrifugation and inflicted on populations of the model organism Caenorhabditis elegans. The generations that follow were monitored for growth in comparison with populations with the same genetics. Centrifugation of the parental generation varied with intensity. Other factors, including lineage and developmental stage at treatment, were tested. There was no significant divergence in population growth …

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Novel Semiconducting Materials Synthesis And Metallic Flux Crystal Growth, August Schwoebel Apr 2023

Novel Semiconducting Materials Synthesis And Metallic Flux Crystal Growth, August Schwoebel

NASA-Missouri Space Grant Consortium

This investigation is focused on attempts to synthesize novel polyatomic or doped semiconducting materials by employment of p-block metal flux crystal growth. First discovered in 1874, semiconductors remain at the forefront of materials and condensed matter research for their unique magnetic properties and expanding technological applications. Utilizing the metal flux crystal growth technique on approximately 38 devised samples, most reactions yielded previously discovered binary or ternary intermetallic compounds, but further analysis would be required to confirm this conclusion. This paper discusses methods for devising sample mixtures to be placed under vacuum and heated to high temperatures for crystal growth, as …

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Development Of Deep Learning Potentials For Ultra-High Temperature High-Entropy Driven Diborides, Gregory Vatrano Apr 2023

Development Of Deep Learning Potentials For Ultra-High Temperature High-Entropy Driven Diborides, Gregory Vatrano

NASA-Missouri Space Grant Consortium

In this study, we developed deep learning potentials for ultra-high temperature high entropy driven diborides of MB2 where M is the transition metal made of Ti, Zr, Hf, Nb, Ta. The materials are being considered as the heat shield for hypersonic vehicles due to their high thermal conductivity and thermal stability. We used quantum mechanical data as our input for training and validation. Specifically, we use the energy, force and stress data from molecular dynamics simulations at elevated temperatures using quantum mechanics calculations. We used the DeePMD neural network code and varied the hyper-parameters such as cut-off radius, batch size, …

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Supersonic Wind Tunnel Improvement For Advanced Laser-Based Non-Intrusive Diagnostics, Joshua Gary Apr 2023

Supersonic Wind Tunnel Improvement For Advanced Laser-Based Non-Intrusive Diagnostics, Joshua Gary

NASA-Missouri Space Grant Consortium

This work presents an approach to the design, and theoretical application, of a new test section for the Missouri S&T Supersonic Wind Tunnel to be used with advanced laserbased non-intrusive diagnostics. Supersonic wind tunnel test sections present multiple challenges. They need to ensure proper flow by avoiding jet-flow interactions and ensuring started conditions; they need to withstand large pressure loads in the case of tunnel unstart; they need to provide easy optical access for advanced diagnostics; they need to be modular and adaptable for different experiments. This work presents detailed analytical and numerical analyses of the mechanical loads. Based on …

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In Situ Confocal Raman Microscopy Of Redox Polymer Films On Bulk Electrode Supports, Jiahe Xu, Miharu Koh, Shelley D. Minteer, Carol Korzeniewski Apr 2023

In Situ Confocal Raman Microscopy Of Redox Polymer Films On Bulk Electrode Supports, Jiahe Xu, Miharu Koh, Shelley D. Minteer, Carol Korzeniewski

Chemistry Faculty Research & Creative Works

A Spectro electrochemical cell is described that enables confocal Raman microscopy studies of electrode-supported films. the confocal probe volume (∼1 μm3) was treated as a fixed-volume reservoir for the observation of potential-induced changes in chemical composition at microscopic locations within an ∼20 μm thickness layer of a redox polymer cast onto a 3 mm diameter carbon disk electrode. using a Raman system with high collection efficiency and wavelength reproducibility, spectral subtraction achieved excellent rejection of background interferences, opening opportunities for measuring within micrometer-scale thickness redox films on widely available, low-cost, and conventional carbon disk electrodes. the cell performance and spectral …

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New Guidelines For Presenting Electrochemical Data In All Acs Journals, Shelley Minteer, Jingguang Chen, Song Lin, Cathleen Crudden, Stefanie Dehnen, Prashant V. Kamat, Marisa Kozlowski, Géraldine Masson, Scott J. Miller Apr 2023

New Guidelines For Presenting Electrochemical Data In All Acs Journals, Shelley Minteer, Jingguang Chen, Song Lin, Cathleen Crudden, Stefanie Dehnen, Prashant V. Kamat, Marisa Kozlowski, Géraldine Masson, Scott J. Miller

Chemistry Faculty Research & Creative Works

No abstract provided.

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