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Advancing Occupational Health In Mining: Investigating Low-Cost Sensors Suitability For Improved Coal Dust Exposure Monitoring, Mirza Muhammad Zaid, Nana Amoah, Ashish Kakoria, Yang Wang, Guang Xu Feb 2024

Advancing Occupational Health In Mining: Investigating Low-Cost Sensors Suitability For Improved Coal Dust Exposure Monitoring, Mirza Muhammad Zaid, Nana Amoah, Ashish Kakoria, Yang Wang, Guang Xu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Exposure to coal dust in underground coal mines poses significant health risks to workers, including the development of diseases such as coal workers' pneumoconiosis and silicosis. Current available methods for monitoring coal dust exposure are expensive and time-consuming, necessitating the exploration of alternative approaches. Low-cost light scattering particulate matter sensors offer a promising solution, and its development in recent years has demonstrated some success in air quality monitoring However, its application in sensing coal particles is limited partially due to that the operating condition in a mine is different than the atmosphere. Thus, the objective of this paper is to …


In Vitro Assessment Of Protamine Toxicity With Neural Cells, Its Therapeutic Potential To Counter Chondroitin Sulfate Mediated Neuron Inhibition, And Its Effects On Reactive Astrocytes, Derek W. Nelson, Jessica L. Funnell, Conrad H. Cheung, Geraldine B. Quinones, Christina S. Mendoza, Marvin Bentley, Ryan J. Gilbert Feb 2024

In Vitro Assessment Of Protamine Toxicity With Neural Cells, Its Therapeutic Potential To Counter Chondroitin Sulfate Mediated Neuron Inhibition, And Its Effects On Reactive Astrocytes, Derek W. Nelson, Jessica L. Funnell, Conrad H. Cheung, Geraldine B. Quinones, Christina S. Mendoza, Marvin Bentley, Ryan J. Gilbert

Chemical and Biochemical Engineering Faculty Research & Creative Works

Multiple therapies have been studied to ameliorate the neuroinhibitory cues present after traumatic injury to the central nervous system. Two previous in vitro studies have demonstrated the efficacy of the Food and Drug Administration-approved cardiovascular therapeutic, protamine (PRM), to overcome neuroinhibitory cues presented by chondroitin sulfates; however, the effect of a wide range of PRM concentrations on neuronal and glial cells has not been evaluated. In this study, we investigate the therapeutic efficacy of PRM with primary cortical neurons, hippocampal neurons, mixed glial cultures, and astrocytes. The threshold for PRM toxicity is shown to be at or above 10 µg …


Dielectric Properties Of Polycrystalline And Single Crystal (100) Strontium Titanate From 4 To 295 K, Hung Trinh, Alan Devoe, Fatih Dogan Jan 2024

Dielectric Properties Of Polycrystalline And Single Crystal (100) Strontium Titanate From 4 To 295 K, Hung Trinh, Alan Devoe, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

The dielectric properties of single crystal and polycrystalline SrTiO3 (ST) were investigated from 295 to 4 K. Relative permittivity (εr) and loss tangent (tan(δ)) were measured systematically as a function of direct current (DC) voltage (0 V/cm to 800 V/cm), frequency (100 Hz to 1 MHz), and temperature (295 K to 4 K) for type (100) single crystal SrTiO3 (SC-ST) and for polycrystalline SrTiO3 (PC-ST). Calculated equivalent series resistance (ESR) data are also reported. Overall, the permittivity of ST showed a dependence on temperature, DC voltage, and frequency. Dependences on voltage and frequency were only observed at …


Modeling Of Single-Lap Joints With Auxetic Adhesive Utilizing Homogeneous And Heterogeneous Bondline Microstructures, Chatarina P. Puspaningtyas, Annisa Jusuf, Bambang K. Hadi, Arief Yudhanto Jan 2024

Modeling Of Single-Lap Joints With Auxetic Adhesive Utilizing Homogeneous And Heterogeneous Bondline Microstructures, Chatarina P. Puspaningtyas, Annisa Jusuf, Bambang K. Hadi, Arief Yudhanto

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Producing lightweight structures can be effectively achieved using adhesive bonding that incorporates a high-performance adhesive, eliminating the mechanical joints (rivet, bolts). Here, the proof-of-concept of tailoring the high-performance adhesive using microstructures exhibiting a negative Poisson's ratio (auxetic) is investigated using two single lap joint (SLJ) models developed in ABAQUS/Standard. The SLJ models consist of two rigid adherends that are bonded using either homogeneous or heterogeneous adhesive that produces auxetic response. In homogeneous adhesive, a negative value of Poisson's ratio is defined in the adhesive part of the models. In heterogeneous adhesive, the negative Poisson's ratio is obtained by explicitly building …


Upconversion Photoluminescence Of Monolayer Wse2 With Biaxial Strain Tuning, Shrawan Roy, Jie Gao, Xiaodong Yang Jan 2024

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 …


Miniaturized Fluorescence Ph Sensor With Assembly Free Ball Lens On A Tapered Multimode Optical Fiber, Bohong Zhang, Farhan Mumtaz, Muhammad Roman, Dinesh Reddy Alla, Rex E. Gerald, Jie Huang Jan 2024

Miniaturized Fluorescence Ph Sensor With Assembly Free Ball Lens On A Tapered Multimode Optical Fiber, Bohong Zhang, Farhan Mumtaz, Muhammad Roman, Dinesh Reddy Alla, Rex E. Gerald, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

In biochemistry, the absence of a compact, assembly-free pH sensor with high sensitivity and signal-to-noise ratio has been a persistent hurdle in achieving accurate pH measurements in real time, particularly in complex liquid environments. This manuscript introduces what we believe to be a novel solution in the form of a miniaturized pH sensor utilizing an assembly-free ball lens on a tapered multimode optical fiber (TMMF), offering the potential to revolutionize pH sensing in biochemical applications. A multimode optical fiber (MMF) was subjected to tapering processes, leading to the creation of an ultra-thin needle-like structure with a cross-sectional diameter of about …


Use Of Hybrid Fibers And Shrinkage Mitigating Materials In Scc For Repair Applications, Kamran Aghaee, Kamal H. Khayat Jan 2024

Use Of Hybrid Fibers And Shrinkage Mitigating Materials In Scc For Repair Applications, Kamran Aghaee, Kamal H. Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Self-consolidating concrete (SCC) is used to repair structural elements with congested reinforcement or restricted access to placement and consolidation. In addition to adequate flowability, passing ability, filling capacity, and stability, adequate bonding to the substrate and reinforcing bars, low shrinkage and cracking resistance are required for successful repair. This study employs various shrinkage mitigating materials, including expansive agent (EA), coupled use of EA with shrinkage reducing admixture (SRA), and EA with pre-saturated lightweight sand (LWS) to fulfill these requirements. The effect of these materials on the performance of SCC made with a hybrid synthetic (PP) fiber and a hybrid steel-synthetic …


Quaternary Rare-Earth Oxyselenides Re4ga2se7o2 (Re = Pr, Nd) With Trigonal Bipyramidal Gase5 Units: Evaluation Of Optical, Thermoelectric, And Electrocatalytic Properties, Vidyanshu Mishra, Ibrahim Munkaila Abdullahi, Dundappa Mumbaraddi, Mohammed Jomaa, Louis Guérin, Manashi Nath, Arthur Mar Jan 2024

Quaternary Rare-Earth Oxyselenides Re4ga2se7o2 (Re = Pr, Nd) With Trigonal Bipyramidal Gase5 Units: Evaluation Of Optical, Thermoelectric, And Electrocatalytic Properties, Vidyanshu Mishra, Ibrahim Munkaila Abdullahi, Dundappa Mumbaraddi, Mohammed Jomaa, Louis Guérin, Manashi Nath, Arthur Mar

Chemistry Faculty Research & Creative Works

Phase-pure samples and single crystals of the rare-earth oxyselenides RE4Ga2Se7O2 (RE = Pr, Nd) were prepared by reactions at 950 °C. They adopt a new structure type (orthorhombic, space group Pnma, a = 11.721(2)-11.683(2) Å, b = 3.9882(7)-3.9667(7) Å, c = 29.644(5)-29.581(5) Å, Z = 4) consisting of RESe6 trigonal prisms, GaSe4 tetrahedra, and GaSe5 trigonal bipyramids linked to form corrugated layers between which strips of edge-sharing RE4O tetrahedra are inserted. The bonding character is mostly ionic within RE-O and RE-Se blocks but mostly covalent with Ga-Se blocks, …


Reactive Capture And Conversion Of Co2 Into Hydrogen Over Bifunctional Structured Ce1-Xcoxnio3/Ca Perovskite-Type Oxide Monoliths, Khaled Baamran, Shane Lawson, Ali A. Rownaghi, Fateme Rezaei Jan 2024

Reactive Capture And Conversion Of Co2 Into Hydrogen Over Bifunctional Structured Ce1-Xcoxnio3/Ca Perovskite-Type Oxide Monoliths, Khaled Baamran, Shane Lawson, Ali A. Rownaghi, Fateme Rezaei

Chemical and Biochemical Engineering Faculty Research & Creative Works

Carbon capture, utilization, and storage (CCUS) technologies are pivotal for transitioning to a net-zero economy by 2050. In particular, conversion of captured CO2 to marketable chemicals and fuels appears to be a sustainable approach to not only curb greenhouse emissions but also transform wastes like CO2 into useful products through storage of renewable energy in chemical bonds. Bifunctional materials (BFMs) composed of adsorbents and catalysts have shown promise in reactive capture and conversion of CO2 at high temperatures. In this study, we extend the application of 3D printing technology to formulate a novel set of BFMs composed …


Dielectric Permittivity Of Pzt 95/5 Ferroelectric Ceramics And 0.27pin-Pmn-0.26pt Single Crystals Under Pulsed High Electric Fields, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Christopher S. Lynch Jan 2024

Dielectric Permittivity Of Pzt 95/5 Ferroelectric Ceramics And 0.27pin-Pmn-0.26pt Single Crystals Under Pulsed High Electric Fields, Sergey I. Shkuratov, Jason Baird, Vladimir G. Antipov, Christopher S. Lynch

Mining Engineering Faculty Research & Creative Works

The dependence of the dielectric permittivity of ferroelectric materials on electric field magnitude impacts the performance of ferroelectric devices. In a ferroelectric generator, a shock wave travels through the ferroelectric element and depolarizes it, and surface charges are released from the element electrodes, resulting in the generation of a megawatt power level for several microseconds. The dielectric properties of the compressed and uncompressed zones of the ferroelectric element affect the generated voltage and energy. The results of previous studies indicate that the low-field dielectric permittivity of poled Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 (PZT 95/5) ferroelectrics in the uncompressed zone differs significantly from the high-field …


Effects Of Organic Surface Contamination On The Mass Accommodation Coefficient Of Water: A Molecular Dynamics Study, Jordan Hartfield, Eric Bird, Zhi Liang Jan 2024

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 …


Retraction Notice To “High Density Conductive Lifepo4 Cathode With Enhanced High-Rate And High Temperature Performance” [Mater. Chem. Phys. 232 (2019) 367–373, (S0254058419304110), (10.1016/J.Matchemphys.2019.05.014)], David Seung-Hyun Lee, Won Bin Im, Xinhua Liang Jan 2024

Retraction Notice To “High Density Conductive Lifepo4 Cathode With Enhanced High-Rate And High Temperature Performance” [Mater. Chem. Phys. 232 (2019) 367–373, (S0254058419304110), (10.1016/J.Matchemphys.2019.05.014)], David Seung-Hyun Lee, Won Bin Im, Xinhua Liang

Chemical and Biochemical Engineering Faculty Research & Creative Works

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. The Editor-in-Chief found that the corresponding author of this article submitted the manuscript to the journal without the consent of the two individuals named as "co-authors", using invented email addresses to impersonate them. In addition, based on the raw materials presented to the journal by the second co-author and the Editor-in-Chief's own investigation, the Editor-in-Chief believes that some results in the paper are fabricated. Based on these two findings, the Editor-in-Chief has decided to retract the …


Unsupervised Blstm-Based Electricity Theft Detection With Training Data Contaminated, Qiushi Liang, Shengjie Zhao, Jiangfan Zhang, Hao Deng Jan 2024

Unsupervised Blstm-Based Electricity Theft Detection With Training Data Contaminated, Qiushi Liang, Shengjie Zhao, Jiangfan Zhang, Hao Deng

Electrical and Computer Engineering Faculty Research & Creative Works

Electricity theft can cause economic damage and even increase the risk of outage. Recently, many methods have implemented electricity theft detection on smart meter data. However, how to conduct detection on the dataset without any label still remains challenging. In this article, we propose a novel unsupervised two-stage approach under the assumption that the training set is contaminated by attacks. Specifically, the method consists of two stages: (1) a Gaussian mixture model is employed to cluster consumption patterns with respect to different habits of electricity usage, and with the goal of improving the accuracy of the model in the posterior …


Rotational Spectrum And Ring Structures Of Silacyclohex-2-Ene And 1,1-Difluorosilacyclohex-2-Ene, Nicole T. Moon, Amanda J. Duerden, Thomas M.C. Mcfadden, Nathan A. Seifert, Gamil A. Guirgis, Garry S. Grubbs Jan 2024

Rotational Spectrum And Ring Structures Of Silacyclohex-2-Ene And 1,1-Difluorosilacyclohex-2-Ene, Nicole T. Moon, Amanda J. Duerden, Thomas M.C. Mcfadden, Nathan A. Seifert, Gamil A. Guirgis, Garry S. Grubbs

Chemistry Faculty Research & Creative Works

Silacyclohex-2-ene and 1,1-difluorosilacyclohex-2-ene have been synthesized, and the chirped-pulse, Fourier-transform microwave spectra of each have been observed and analyzed from 4.9 to 23.1 GHz. Quantum chemical calculations have been performed at the B3LYP-D3BJ/Def2TZVP level of theory and predict μa to be the largest dipole moment component with a significantly larger value in this component for 1,1-difluorosilacyclohex-2-ene. In accordance with this prediction, the spectra were predominantly a-type with the observation of a few b- and c-type transitions. The signal-to-noise ratio was adequate in both spectra to observe 29Si, 30Si, and all singly substituted 13C isotopologues in natural …


One-Pot Assembly Of Drug-Eluting Silk Coatings With Applications For Nerve Regeneration, Tanner D. Fink, Jessica L. Funnell, Ryan J. Gilbert, R. Helen Zha Jan 2024

One-Pot Assembly Of Drug-Eluting Silk Coatings With Applications For Nerve Regeneration, Tanner D. Fink, Jessica L. Funnell, Ryan J. Gilbert, R. Helen Zha

Chemical and Biochemical Engineering Faculty Research & Creative Works

Clinical use of polymeric scaffolds for tissue engineering often suffers from their inability to promote strong cellular interactions. Functionalization with biomolecules may improve outcomes; however, current functionalization approaches using covalent chemistry or physical adsorption can lead to loss of biomolecule bioactivity. Here, we demonstrate a novel bottom-up approach for enhancing the bioactivity of poly (l-lactic acid) electro spun scaffolds though interfacial coassembly of protein payloads with silk fibroin into nano thin coatings. In our approach, protein payloads are first added into an aqueous solution with Bombyx mori-derived silk fibroin. Phosphate anions are then added to trigger coassembly of the payload …


Hanford Low-Activity Waste Vitrification: A Review, José Marcial, Brian J. Riley, Albert A. Kruger, Charmayne E. Lonergan, John D. Vienna Jan 2024

Hanford Low-Activity Waste Vitrification: A Review, José Marcial, Brian J. Riley, Albert A. Kruger, Charmayne E. Lonergan, John D. Vienna

Materials Science and Engineering Faculty Research & Creative Works

This Paper Summarizes the Vast Body of Literature (Over 200 Documents) Related to Vitrification of the Low-Activity Waste (LAW) Fraction of the Hanford Tank Wastes. Details Are Provided on the Origins of the Hanford Tank Wastes that Resulted from Nuclear Operations Conducted between 1944 and 1989 to Support Nuclear Weapons Production. Waste Treatment Processes Are Described, Including the Baseline Process to Separate the Tank Waste into LAW and High-Level Waste Fractions, and the LAW Vitrification Facility Being Started at Hanford. Significant Focus is Placed on the Glass Composition Development and the Property-Composition Relationships for Hanford LAW Glasses. Glass Disposal Plans …


Splitfed-Based Patient Severity Prediction And Utility Maximization In Industrial Healthcare 4.0, Himanshu Singh, Biken Moirangthem, Ajay Pratap, Shilpi Kumari, Abhishek Kumar, Sajal K. Das Jan 2024

Splitfed-Based Patient Severity Prediction And Utility Maximization In Industrial Healthcare 4.0, Himanshu Singh, Biken Moirangthem, Ajay Pratap, Shilpi Kumari, Abhishek Kumar, Sajal K. Das

Computer Science Faculty Research & Creative Works

The healthcare industry has transitioned from traditional healthcare 1.0 to AI-powered healthcare 4.0. However, overall cost for patient treatment remains high and challenging to manage due to the absence of a centralized cost evaluation mechanism before hospital visits. Therefore, in this paper, we devise a cloud-based mechanism to calculate hospitals' star rating based on questionnaire with the application of Z-score and K∗clustering algorithm. To evaluate disease severity at cloud, splitfed technique is utilized in coordination with Wireless Body Area Network (WBAN). Finally, the cloud calculates provisional treatment costs and finds a preferable hospital with a low payable treatment cost and …


Lipschitz Stability For Impulsive Riemann–Liouville Fractional Differential Equations, Martin Bohner, Snezhana Hristova Jan 2024

Lipschitz Stability For Impulsive Riemann–Liouville Fractional Differential Equations, Martin Bohner, Snezhana Hristova

Mathematics and Statistics Faculty Research & Creative Works

Initial and impulsive conditions for initial value problems of systems of nonlinear impulsive Riemann–Liouville fractional differential equations are introduced. The case when the lower limit of the fractional derivative is changed at each time point of the impulses is studied. In the case studied, the solution has a singularity at the initial time and at any point of the impulses. This leads to the need to appropriately generalize the classical concept of Lipschitz stability. Two derivative types of Lyapunov functions are utilized in order to deduce sufficient conditions for the new stability concept. Three examples are provided for illustration purpose …


Existence Of Solutions By Coincidence Degree Theory For Hadamard Fractional Differential Equations At Resonance, Martin Bohner, Alexander Domoshnitsky, Seshadev Padhi, Satyam Narayan Srivastava Jan 2024

Existence Of Solutions By Coincidence Degree Theory For Hadamard Fractional Differential Equations At Resonance, Martin Bohner, Alexander Domoshnitsky, Seshadev Padhi, Satyam Narayan Srivastava

Mathematics and Statistics Faculty Research & Creative Works

Using the Coincidence Degree Theory of Mawhin and Constructing Appropriate Operators, We Investigate the Existence of Solutions to Hadamard Fractional Differential Equations (FRDEs) at Resonance


On A Fully Coupled Nonlocal Multipoint Boundary Value Problem For A Dual Hybrid System Of Nonlinear Q -Fractional Differential Equations, Ahmed Alsaedi, Martin Bohner, Bashir Ahmad, Boshra Alharbi Jan 2024

On A Fully Coupled Nonlocal Multipoint Boundary Value Problem For A Dual Hybrid System Of Nonlinear Q -Fractional Differential Equations, Ahmed Alsaedi, Martin Bohner, Bashir Ahmad, Boshra Alharbi

Mathematics and Statistics Faculty Research & Creative Works

A new class of nonlocal multipoint boundary value problems involving a dual hybrid system of nonlinear Riemann-Liouville-type q-fractional differential equations is studied in this paper. Existence and uniqueness results for the given problem are derived by applying the Leray-Schauder nonlinear alternative and the Banach contraction mapping principle. Examples are presented for illustrating the obtained results. The work established in this paper is a useful contribution to the existing literature on q-fractional differential equations. Some interesting special cases are also discussed.


Inspire Newsletter Spring 2024, Missouri University Of Science And Technology Inspire - University Transportation Center Jan 2024

Inspire Newsletter Spring 2024, Missouri University Of Science And Technology Inspire - University Transportation Center

INSPIRE Newsletters

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Accurate And Time Efficient Signal Integrity And Power Integrity Modeling Of High-Speed Digital Systems, Chaofeng Li Jan 2024

Accurate And Time Efficient Signal Integrity And Power Integrity Modeling Of High-Speed Digital Systems, Chaofeng Li

Doctoral Dissertations

"Signal integrity (SI) and power integrity (PI) play an important role in the modern high-speed digital system design, which are closely related to the printed circuit board (PCB) dielectric material property, the PCB interconnect performance, and the power delivery network (PDN) on PCB. Generally, the full-wave simulation is used to accurately analyze and evaluate the designed PCB. But full-wave simulation is not a good option for the complex PCB structure with high aspect ratio, for example, PCB vias, and PDN, which will require significant computing time and storage resources. Equivalent circuit models have been developed to efficiently predict the electrical …


In Situ Infrared Thermographic Inspection In Additive Manufacturing, Tao Liu Jan 2024

In Situ Infrared Thermographic Inspection In Additive Manufacturing, Tao Liu

Doctoral Dissertations

"Laser Powder Bed Fusion (LPBF) is a key technique in metal additive manufacturing and has undergone extensive research over the past few decades. It enables the fabrication of complex geometries directly from digital design models. The solidification process in LPBF is heavily influenced by the characteristics of the powder layer, including its thickness and thermal transport properties. Additionally, the performance of the printed part is impacted by the temperature history during solidification and the final residual stress field. While these topics have been the focus of many studies, almost all research has concentrated on ex-situ measurement and testing. These ex-situ …


Pseudo-Three-Dimensional Back-Analysis Of Rainfall-Induced Landslides In Utuado, Puerto Rico, Mirna Kassem, Weibing Gong, Dimitrios Zekkos, Marin Clark, Stephen Hughes Jan 2024

Pseudo-Three-Dimensional Back-Analysis Of Rainfall-Induced Landslides In Utuado, Puerto Rico, Mirna Kassem, Weibing Gong, Dimitrios Zekkos, Marin Clark, Stephen Hughes

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Regional slope stability analyses can provide a system-level assessment of landslide susceptibility. This study aims to develop a regional back-analysis model for rainfall-induced landslides to compute ground shear strength that can be used for landslide prediction. Most commonly, mechanistic-based models for regional slope stability consist of simplified one-dimensional (1D) analyses compared to more realistic three-dimensional (3D) procedures. A pseudo-3D methodology is applied on 788 landslides over two 2.5 km2 areas in the plutonic rocks of the Utuado Batholith. First, an infinite slope stability triggering model is applied on a 1 m-resolution digital elevation model (DEM) to identify the triggering grid …


High-Temperature Oxidation Behavior Of High Entropy Carbide (Tanbtiv)C In Atmospheres With Different Oxygen Contents, Ruoyu Chen, Hongbin An, Jie Zhan, Saisai Li, Aiqin Mao, Haiming Wen Jan 2024

High-Temperature Oxidation Behavior Of High Entropy Carbide (Tanbtiv)C In Atmospheres With Different Oxygen Contents, Ruoyu Chen, Hongbin An, Jie Zhan, Saisai Li, Aiqin Mao, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

A high entropy carbide (TaNbTiV)C was fabricated via spark plasma sintering of high entropy powders that were prepared using a molten salt method. The as-fabricated high entropy carbide was then investigated for its high-temperature oxidation behavior at 850 °C, under atmospheres with three different oxygen contents (20 vol%, 40 vol%, and 60 vol%). After the high-temperature oxidation process, the main phases observed in all the specimens were incompletely oxidized phase (NbxTi1-x)CyO2-y and oxides (Nb0.5Ta0.5)2O5, TiO2, and Nb2O5. Importantly, the …


Synergistic Hardening In A Dual Phase High-Entropy (Hf,Nb,Ta,Ti,Zr)C–(Hf,Nb,Ta,Ti,Zr)B2 Ultra-High Temperature Ceramic, Rubia Hassan, William G. Fahrenholtz, Gregory E. Hilmas, Stefano Curtarolo Jan 2024

Synergistic Hardening In A Dual Phase High-Entropy (Hf,Nb,Ta,Ti,Zr)C–(Hf,Nb,Ta,Ti,Zr)B2 Ultra-High Temperature Ceramic, Rubia Hassan, William G. Fahrenholtz, Gregory E. Hilmas, Stefano Curtarolo

Materials Science and Engineering Faculty Research & Creative Works

A dual phase high-entropy (Hf,Nb,Ta,Ti,Zr)C–(Hf,Nb,Ta,Ti,Zr)B2 ultra-high temperature ceramic was synthesized using a single step boro-carbothermal reduction route. The synthesized powder was densified by spark plasma sintering at 2000°C, resulting in complete solid solution formation and a relative density of ≈99%. The dual phase ceramic was 43 vol% high-entropy carbide and 57 vol% high-entropy boride. The grain sizes were 0.85 ± 0.34 µm for the carbide and 0.87 ± 0.33 µm for the boride with minimal residual oxide (0.2 vol%) detected in the microstructure. The resulting composition had a higher microhardness than the individual boride and carbide ceramics across the range …


Cf/Sic Ceramic Matrix Composites With Extraordinary Thermomechanical Properties Up To 2000 °C, Min Sung Park, Jian Gu, Heesoo Lee, Sea Hoon Lee, Lun Feng, William Fahrenholtz Jan 2024

Cf/Sic Ceramic Matrix Composites With Extraordinary Thermomechanical Properties Up To 2000 °C, Min Sung Park, Jian Gu, Heesoo Lee, Sea Hoon Lee, Lun Feng, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

The thermomechanical properties of carbon fiber reinforced silicon carbide ceramic matrix composites (Cf/SiC CMCs) were studied up to 2000 °C using high temperature in situ flexural testing in argon. The CMC specimens were fabricated using an ultrahigh concentration (66 vol%) aqueous slurry containing nano-sized silicon carbide powder. The SiC powder compacts were obtained by drying the slurry and were densified using the precursor impregnation and pyrolysis (PIP) method with field assisted sintering technology/spark plasma sintering (FAST/SPS). The high relative density of the SiC green body (77.6%) enabled densification within 2.5 days using four PIP cycles. In contrast, conventional PIP processes …


Phosphate-Based Dechlorination Of Electrorefiner Salt Waste Using A Phosphoric Acid Precursor, Paige Murray, Harmony Werth, Sean Sullivan, Brian J. Riley, Michael Simpson, Charmayne E. Lonergan, Krista Carlson Jan 2024

Phosphate-Based Dechlorination Of Electrorefiner Salt Waste Using A Phosphoric Acid Precursor, Paige Murray, Harmony Werth, Sean Sullivan, Brian J. Riley, Michael Simpson, Charmayne E. Lonergan, Krista Carlson

Materials Science and Engineering Faculty Research & Creative Works

Electrochemical processing of spent nuclear fuel in molten chloride salts results in radioactive salt waste. Chlorine removal from the salt has been identified as an effective and efficient first step in the management of high-level waste. In this work, a simple salt was dechlorinated with a phosphoric acid phosphate precursor, resulting in a glassy dechlorinated product. The dechlorination efficacy was evaluated in air and argon environments. This work serves as an initial step to advance the technological readiness level of h3po4-based dechlorination step toward implementation of iron phosphate waste forms to immobilize electrochemical fuel reprocessing salt waste streams.


Thermal And Electrical Properties Of Single-Phase High Entropy Carbide Ceramics, Paul M. Brune, Gregory E. Hilmas, William G. Fahrenholtz, Jeremy Lee Watts, Stefano Curtarolo Jan 2024

Thermal And Electrical Properties Of Single-Phase High Entropy Carbide Ceramics, Paul M. Brune, Gregory E. Hilmas, William G. Fahrenholtz, Jeremy Lee Watts, Stefano Curtarolo

Materials Science and Engineering Faculty Research & Creative Works

Thermal and Electrical Properties Were Investigated for Five Nominally Phase-Pure High Entropy Carbide Ceramics. the Compositions (Hf0.2Nb0.2Ta0.2Ti0.2Zr0.2)C, (Cr0.2Hf0.2Ta0.2Ti0.2Zr0.2)C, (Hf0.2Mo0.2Ta0.2Ti0.2Zr0.2)C, (Hf0.2Ta0.2Ti0.2W0.2Zr0.2)C, and (Hf0.2Mo0.2Ti0.2W0.2Zr0.2)C Were Synthesized by Carbothermal Reduction of Oxides. the Thermal Diffusivity and Heat Capacity Were Measured from Room Temperature to 1800°C. the Room Temperature Thermal Conductivity Ranged from 5.1 W/mK for (Hf0.2Mo0.2Ti0.2W0.2Zr0.2)C to 9.0 W/mK for (Cr0.2Hf0.2Ta0.2Ti0.2Zr0.2)C. the Thermal Conductivity Increased over the Temperature Range with Maximum Conductivities of 19.6 W/mK Measured for (Hf0.2Mo0.2Ta0.2Ti0.2Zr0.2)C to 29.7 W/mK for (Cr0.2Hf0.2Ta0.2Ti0.2Zr0.2)C at 1800°C. the Electron Contribution to Thermal Conductivity Calculated from Measured Electrical Resistivity Varied from 41% to 52% of the …


Pressureless Sintering And Properties Of Additively Manufactured Zrb2–Sic, Marharyta Lakusta, Nicholas M. Timme, Jeremy L. Watts, William G. Fahrenholtz, Gregory E. Hilmas, David W. Lipke Jan 2024

Pressureless Sintering And Properties Of Additively Manufactured Zrb2–Sic, Marharyta Lakusta, Nicholas M. Timme, Jeremy L. Watts, William G. Fahrenholtz, Gregory E. Hilmas, David W. Lipke

Materials Science and Engineering Faculty Research & Creative Works

Densification behavior, grain growth kinetics, mechanical and thermal properties of pressurelessly sintered zirconium diboride–silicon carbide (ZrB2–SiC) fabricated by extrusion of high solids loading pastes have been studied. The effects of sintering temperature (1600–2300°C), heating rate during constant heating rate sintering (10–50°C/min), and time during isothermal sintering (3–24 h) on density and grain size were examined. The apparent activation energy for densification was determined to be 940 ± 90 kJ/mol, suggesting lattice diffusion as the dominant sintering mechanism. Grain growth of both ZrB2 and SiC followed a normal grain growth power law with grain growth exponent n = 2 indicating diffusion-controlled …