Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Mechanical Engineering (51)
- Manufacturing (30)
- Civil and Environmental Engineering (26)
- Electrical and Computer Engineering (22)
- Aerospace Engineering (21)
-
- Structural Materials (19)
- Chemical Engineering (17)
- Physical Sciences and Mathematics (11)
- Biology (10)
- Life Sciences (10)
- Chemistry (9)
- Space Habitation and Life Support (9)
- Space Vehicles (9)
- Structures and Materials (9)
- Curriculum and Instruction (8)
- Education (8)
- Educational Administration and Supervision (8)
- Educational Assessment, Evaluation, and Research (8)
- Educational Leadership (8)
- Educational Methods (8)
- Metallurgy (8)
- Semiconductor and Optical Materials (7)
- Biochemical and Biomolecular Engineering (5)
- Architectural Engineering (4)
- Architecture (4)
- Engineering Mechanics (4)
- Engineering Science and Materials (4)
- Keyword
-
- Mechanical properties (11)
- Hardness (9)
- Bioactive glass (8)
- Sintering (8)
- Spark plasma sintering (8)
-
- Microstructure (7)
- Rheology (7)
- Superconductivity (7)
- Additive manufacturing (6)
- Borides (6)
- Compressive strength (6)
- Electrical conductivity (6)
- ZrB 2 (6)
- Ultra-High Temperature Ceramics (5)
- Ultra-high temperature ceramics (5)
- 3D printers (4)
- Additive Manufacturing (4)
- Capacitors (4)
- Carbides (4)
- Ceramic (4)
- Critical current (4)
- Densification (4)
- Glass (4)
- Kinetics (4)
- Laser heating (4)
- Mechanical Properties (4)
- Selective laser sintering (4)
- Spark Plasma Sintering (4)
- Strength (4)
- Thermal Conductivity (4)
- Publication Year
- Publication
-
- Materials Science and Engineering Faculty Research & Creative Works (326)
- Masters Theses (118)
- Bachelors Theses (62)
- Doctoral Dissertations (61)
- Mechanical and Aerospace Engineering Faculty Research & Creative Works (24)
-
- Electrical and Computer Engineering Faculty Research & Creative Works (16)
- Biological Sciences Faculty Research & Creative Works (5)
- Opportunities for Undergraduate Research Experience Program (OURE) (5)
- Miners Solving for Tomorrow Research Conference (4)
- PSMRC Faculty Research (4)
- Mathematics and Statistics Faculty Research & Creative Works (3)
- Civil, Architectural and Environmental Engineering Faculty Research & Creative Works (2)
- Nuclear Engineering and Radiation Science Faculty Research & Creative Works (2)
- Professional Degree Theses (2)
- Chemical and Biochemical Engineering Faculty Research & Creative Works (1)
- NASA-Missouri Space Grant Consortium (1)
- Undergraduate Research Conference at Missouri S&T (1)
- Publication Type
Articles 61 - 90 of 637
Full-Text Articles in Ceramic Materials
The Effect Of Mold Flux Wetting Conditions With Varying Crucible Materials On Crystallization, Muhammad Anwarul Nazim, Arezoo Emdadi, Todd Sander, Ronald O'Malley
The Effect Of Mold Flux Wetting Conditions With Varying Crucible Materials On Crystallization, Muhammad Anwarul Nazim, Arezoo Emdadi, Todd Sander, Ronald O'Malley
Materials Science and Engineering Faculty Research & Creative Works
Understanding mold flux crystallization is essential for assessing heat transfer during steel casting. The complexity of the mold gap presents challenges in identifying the optimal testing method and nucleation type. This study investigates how variations in wetting properties influence nucleation dynamics, in particular the wetting behaviors of mold flux in platinum and graphite crucibles and how they affect crystallization temperatures and solidification mechanisms. Advanced analytical techniques, including confocal laser scanning microscopy (CLSM), and differential scanning calorimetry (DSC) were employed to analyze nucleation under different conditions, with calibration using synthetic slag, Li2SO4, and thermodynamic equilibrium simulations. The findings highlight the crucial …
Viscoelastic Protective Armor Liners And Protective Armor, Fatih Dogan, Cody Thomas, Catherine Johnson
Viscoelastic Protective Armor Liners And Protective Armor, Fatih Dogan, Cody Thomas, Catherine Johnson
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Rheology And Early-Age Structure Development In Binary And Ternary Blends Modified With Novel Graphene Types, Sahil Surehali, Collin Gustafson, Sayee Srikarah Volaity, Ranjith Divigalpitiya, Aditya Kumar, Narayanan Neithalath
Rheology And Early-Age Structure Development In Binary And Ternary Blends Modified With Novel Graphene Types, Sahil Surehali, Collin Gustafson, Sayee Srikarah Volaity, Ranjith Divigalpitiya, Aditya Kumar, Narayanan Neithalath
Materials Science and Engineering Faculty Research & Creative Works
Interest in the use of graphene to enhance the properties of cementitious materials is growing, but major impediments in implementation are the cost of graphene and changes in binder rheology attributable to these nanomaterials. This study explores the influence of novel, cost-effective, environment-friendly, and mass-producible graphene on the rheology and early-age structure development of cementitious binders. Two novel graphene types—fractal graphene (FG) and reactive graphene (RG)—are used in plain cement mixtures as well as those containing 30 % (by mass) of fly ash and/or limestone powder, at low dosages of ≤0.02 % by mass of binder. The early- and later-age …
Thermally Stimulated Stiffening And Fly Ash's Alkaline Activation By Ca(Oh)2 Addition Facilitates 3d-Printing, Xiaodi Dai, Sharu Bhagavathi Kandy, Narayanan Neithalath, Aditya Kumar, Mathieu Bauchy, Edward Garboczi, Torben Gaedt, Samanvaya Srivastava, Gaurav Sant
Thermally Stimulated Stiffening And Fly Ash's Alkaline Activation By Ca(Oh)2 Addition Facilitates 3d-Printing, Xiaodi Dai, Sharu Bhagavathi Kandy, Narayanan Neithalath, Aditya Kumar, Mathieu Bauchy, Edward Garboczi, Torben Gaedt, Samanvaya Srivastava, Gaurav Sant
Materials Science and Engineering Faculty Research & Creative Works
3D-printing could offer substantial benefits to the construction industry including the fabrication of customized/bespoke components, eliminating formwork, and reducing material waste. Despite these advantages, control of the pumpability, extrudability, and buildability of 3D-printed concrete (3DPC) remains challenging. This study demonstrates how the use of fly ash (FA) enables enhanced thermal stiffening, and rapid alkali-activation in the presence of portlandite (Ca(OH)2, CH). In general, blends of CH and FA exhibit less structural build-up at low temperatures, but upon reaching a trigger temperature of 75 °C, these blends achieve rapid stiffening, at rates of ∼800 Pa/s. The rapid stiffening arises from the …
Elevated Temperature Performance: Arc-Jet Testing Of Carbon Fiber Reinforced Zrb2 Bars Up To 2200 °C For Strength Retention Assessment, D. Sciti, A. Vinci, L. Zoli, P. Galizia, M. Mor, W. Fahrenholtz, S. Mungiguerra, R. Savino, A. M. Caporale, A. Airoldi
Elevated Temperature Performance: Arc-Jet Testing Of Carbon Fiber Reinforced Zrb2 Bars Up To 2200 °C For Strength Retention Assessment, D. Sciti, A. Vinci, L. Zoli, P. Galizia, M. Mor, W. Fahrenholtz, S. Mungiguerra, R. Savino, A. M. Caporale, A. Airoldi
Materials Science and Engineering Faculty Research & Creative Works
For the first time, ultra-high temperature ceramic matrix composite bars were tested inside an arc-jet facility to investigate the impact of oxidation damage on strength retention. The composite bars, which were based on a ZrB2 / SiC matrix reinforced with 45 vol% carbon fibers, were produced by slurry impregnation and sintering. The first batch was tested under 3-point (pt) bending, and two additional batches were exposed to plasma of dissociated air up to a temperature of 2200 °C for 2 min or 2.2 min and then subjected to 3-pt bending. More than 75% of the initial strength was retained even …
Effects Of Gypsum And Limestone On Early-Age Hydration And Strength Optimization In Belite Calcium Sulfoaluminate Cement, Sai Akshay Ponduru, Bryan K. Aylas-Paredes, Taihao Han, Advaith Neithalath, Narayanan Neithalath, Gaurav Sant, Aditya Kumar
Effects Of Gypsum And Limestone On Early-Age Hydration And Strength Optimization In Belite Calcium Sulfoaluminate Cement, Sai Akshay Ponduru, Bryan K. Aylas-Paredes, Taihao Han, Advaith Neithalath, Narayanan Neithalath, Gaurav Sant, Aditya Kumar
Materials Science and Engineering Faculty Research & Creative Works
Belite calcium sulfoaluminate cement (CSAB), an alternative to Portland cement, exhibits excellent strength at both early and later ages. However, due to its high belite content, the carbon reduction from this type of cement is not sufficient when compared to other alternative cements. To further enhance CSAB's sustainability, this study investigates the performance of CSAB when partially replaced by low-carbon mineral additives (i.e., limestone and gypsum). The primary objective is to identify the optimal mixture design by incorporating gypsum and limestone to formulate a sustainable binder that maintains high compressive strength. The CSAB is replaced (with both additives) by up …
Spark Plasma Sintering Of (Zr,Nb)C Ceramics, Jacob Stacy, Greg Hilmas, Jeremy Watts, Brian Taylor, Jhonathan Rosales
Spark Plasma Sintering Of (Zr,Nb)C Ceramics, Jacob Stacy, Greg Hilmas, Jeremy Watts, Brian Taylor, Jhonathan Rosales
Materials Science and Engineering Faculty Research & Creative Works
A range of (Zr,Nb)C ceramics containing 20–50 vol% NbC were spark plasma sintered at 2000°C. The ceramics had relative densities greater than 97 %, and all compositions formed a complete solid solution. The average grain size was ∼7.1 µm over all compositions. Elastic moduli values ranged from 436 to 445 GPa, and the fracture toughness ranged from 0.8 to 2.8 MPa·m1/2 over the compositional range, both increasing with increasing NbC content. The hardnesses of the (Zr,Nb)C ceramics ranged from 19.1 to 20.2 GPa at a load of 9.81 N. The flexural strength increased from 352 to 395 MPa as the …
Distributed Sapphire Fiber Bragg Grating-Based Thermal Profiling Of Submerged Entry Nozzles, Farhan Mumtaz, Hanok W. Tekle, Bohong Zhang, Xiaodong Li, Sunday Abraham, Bryant Mathis, Jeffrey D. Smith, Ronald J. O'Malley, Jie Huang
Distributed Sapphire Fiber Bragg Grating-Based Thermal Profiling Of Submerged Entry Nozzles, Farhan Mumtaz, Hanok W. Tekle, Bohong Zhang, Xiaodong Li, Sunday Abraham, Bryant Mathis, Jeffrey D. Smith, Ronald J. O'Malley, Jie Huang
Electrical and Computer Engineering Faculty Research & Creative Works
This article focuses on the application of sapphire fiber Bragg gratings (FBGs) for instrumentation in submerged entry nozzles (SENs) within the steelmaking industry. The SEN is pivotal for transferring molten steel from a tundish to a mold, while preventing the infiltration of oxygen and nitrogen from the surrounding environment. Maintaining optimal flow conditions in the mold is crucial for ensuring casting process stability and maintaining high-quality steel. Sapphire FBG sensors have been instrumented in SENs to enable distributed thermal mapping for monitoring the health of the SEN. The optical sensor comprises three cascaded sapphire FBGs inscribed using femtosecond (FS) laser …
Flexural Strength Of (Hf,Nb,Ta,Ti,Zr)B2–(Hf,Nb,Ta,Ti,Zr)C High-Entropy Dual-Phase Ceramics, Rubia Hassan, William G. Fahrenholtz, Gregory E. Hilmas, Jeremy Watts
Flexural Strength Of (Hf,Nb,Ta,Ti,Zr)B2–(Hf,Nb,Ta,Ti,Zr)C High-Entropy Dual-Phase Ceramics, Rubia Hassan, William G. Fahrenholtz, Gregory E. Hilmas, Jeremy Watts
Materials Science and Engineering Faculty Research & Creative Works
The room and elevated temperature flexural strengths were measured for (Hf,Nb,Ta,Ti,Zr)B2–(Hf,Nb,Ta,Ti,Zr)C high-entropy dual-phase ceramics. The fracture of ceramics originated from two distinct flaw populations that were either surface defects introduced during specimen preparation or volume defects introduced during processing. The average strength at room temperature was 638 ± 94 MPa with individual bars strengths as high as ∼800 MPa. At 1800°C, average strength increased to 786 ± 265 MPa with individual bar strengths as high as ∼1050 MPa. Above 1800°C, creep dominated resulting in deformation of the bars without fracture. The fracture mode changed from completely trans granular at room …
Dual-Bed Radioiodine Capture From Complex Gas Streams With Zeolites: Regeneration And Reuse Of Primary Sorbent Beds For Sustainable Waste Management, Krista Carlson, Brian J. Riley, Joshua Turner, David C. Cantu, Dev Chidambaram, Charmayne Lonergan, Jeffrey D. Rimer
Dual-Bed Radioiodine Capture From Complex Gas Streams With Zeolites: Regeneration And Reuse Of Primary Sorbent Beds For Sustainable Waste Management, Krista Carlson, Brian J. Riley, Joshua Turner, David C. Cantu, Dev Chidambaram, Charmayne Lonergan, Jeffrey D. Rimer
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Degradation Of Radioactive Waste Encapsulation Of Bao−Feox−P2o5 Glass Evaluated From Electrical Conductivity, Kazuki Mitsui, Nobuyasu Nishioka, Hiromichi Takebe, Richard K. Brow, Akira Saitoh
Degradation Of Radioactive Waste Encapsulation Of Bao−Feox−P2o5 Glass Evaluated From Electrical Conductivity, Kazuki Mitsui, Nobuyasu Nishioka, Hiromichi Takebe, Richard K. Brow, Akira Saitoh
Materials Science and Engineering Faculty Research & Creative Works
We report on the electrical conductivity of barium iron phosphate glass, a candidate for radioactive waste encapsulating glass. The glass composition has been optimized for slow dissolution in hot water because the precipitation of a stable hydration layer of FeO(OH) on the glass surface enhances the water durability of the glass. The mechanism of electrical conductivity of the glass is assumed to be an electron hopping between the electronic energy levels of Fe (II) and Fe (III) ions, obeying the electron carrier generation of Fe (II) → Fe (III) + e−. The electrical conductivity of the base glass was ∼3.2 …
Ground Testing Of A Magnetic-Electrostatic Separation System For Lunar Regolith Beneficiation, Peter Bachle, Charles Wood, Jeffrey Smith, Fateme Rezaei, David Bayless, William Schonberg, Daoru Han
Ground Testing Of A Magnetic-Electrostatic Separation System For Lunar Regolith Beneficiation, Peter Bachle, Charles Wood, Jeffrey Smith, Fateme Rezaei, David Bayless, William Schonberg, Daoru Han
Materials Science and Engineering Faculty Research & Creative Works
The separation of lunar regolith by mineral composition and size category is useful forin-situ resource utilization (ISRU). The research presented herein discusses the designing and development of equipment that has the potential to separate lunar regolith into aluminum, iron-titanium, and magnesium-iron ores. Along with the metal ore separation, this equipment shows the potential to separate regolith by size categories. The combined effect of these separation methods generates output that is valuable to subsequent use in metal and oxygen extraction, additive manufacturing, and regolith sintering processes. The designed equipment uses a dual-strength magnet system with N42 and N52 neodymium magnets for …
Evaluation Of Processing Conditions For The Reduction Of Electrochemical Salt Waste Using Phosphate-Based Dechlorination, Harmony Werth, Jade Beland, Paige Murray, Dave Liang, Laurel Sharpless, Jonathan Evarts, Charmayne Lonergan, Brian J. Riley, Michael Simpson, Krista Carlson
Evaluation Of Processing Conditions For The Reduction Of Electrochemical Salt Waste Using Phosphate-Based Dechlorination, Harmony Werth, Jade Beland, Paige Murray, Dave Liang, Laurel Sharpless, Jonathan Evarts, Charmayne Lonergan, Brian J. Riley, Michael Simpson, Krista Carlson
Materials Science and Engineering Faculty Research & Creative Works
Electrochemical processing of used nuclear fuel in molten chloride salts generates complex radioactive salt waste. Dechlorination of waste salt using phosphate compounds at elevated temperatures (∼600 °C) reduces the volume of material for disposal while evolving gaseous chlorine compounds that could be used to transform metallic uranium into UCl3. In this study, the effects of processing temperature, environment (air or argon), and H3PO4 precursor-to-chlorine ratio on the dechlorination efficacy of a simple alkali salt mixture (SSM) and a salt waste simulant (ERV3) were evaluated. For both salts, the highest chlorine release was concurrent with the water boiling. For the SSM, …
Zrc Particle Size Effect On The Mechanical Properties Of Spark Plasma Sintered 60–40 Vol% Zrc–Mo Cermets, Nathaniel Blatt, Jeremy Watts, Brian Taylor, Jhonathan Rosales, Gregory Hilmas
Zrc Particle Size Effect On The Mechanical Properties Of Spark Plasma Sintered 60–40 Vol% Zrc–Mo Cermets, Nathaniel Blatt, Jeremy Watts, Brian Taylor, Jhonathan Rosales, Gregory Hilmas
Materials Science and Engineering Faculty Research & Creative Works
Cermet's of 60 vol% ZrC and 40 vol% Mo with different starting ZrC particle sizes were spark plasma sintered to full density at 1950 °C. Elastic moduli, Vickers hardness and fracture toughness were measured at room temperature and flexural strength was measured up to 1600 °C. Young's modulus was 365 ± 5 GPa, shear modulus was 149 ± 2 GPa, Poisson's ratio was 0.22 ± 0.01, and no significant difference was observed for the moduli with respect to the starting ZrC particle size. Room temperature flexural strength was affected by the ZrC particle size, measured as ∼524 and ∼598 MPa …
Ultrafast Belite (Β-C2s) Production Using Biofuel-Based Combustion Synthesis, Shubham Agrawal, Sayee Srikarah Volaity, Oluwadamilare Charles Adesina, Bryan K. Aylas-Paredes, Taihao Han, Srinivas Kilambi, Aditya Kumar, Narayanan Neithalath
Ultrafast Belite (Β-C2s) Production Using Biofuel-Based Combustion Synthesis, Shubham Agrawal, Sayee Srikarah Volaity, Oluwadamilare Charles Adesina, Bryan K. Aylas-Paredes, Taihao Han, Srinivas Kilambi, Aditya Kumar, Narayanan Neithalath
Materials Science and Engineering Faculty Research & Creative Works
This study presents a novel low-temperature, combustion synthesis (CS) approach for the rapid production of belite-rich cements. CS leverages the exothermic heat released from the combustion of biofuels such as lignin and/or biomass, intermixed with pelletized limestone and quartz. At an imposed furnace temperature of ∼700°C (as opposed to 1200°C–1300°C required in a conventional kiln), the source materials are rapidly transformed to belite, resulting in energy, emissions, and economic benefits. This work explores the influence of various process parameters, viz., fuel types and contents, airflow rate, porosity, holding temperature, and holding time on the efficiency of CS-based belite synthesis. Through …
Advancing Temperature Monitoring Of The Bottom Anode In A Direct Current Electric Arc Furnace Operations With Distributed Optical Fiber Sensors., Ogbole Collins Inalegwu, Rony Kumer Saha, Yeshwanth Reddy Mekala, Farhan Mumtaz, Nicholas Dionise, Zane Voss, Jeffrey D. Smith, Ronald J. O'Malley, Rex E. Gerald, Jie Huang
Advancing Temperature Monitoring Of The Bottom Anode In A Direct Current Electric Arc Furnace Operations With Distributed Optical Fiber Sensors., Ogbole Collins Inalegwu, Rony Kumer Saha, Yeshwanth Reddy Mekala, Farhan Mumtaz, Nicholas Dionise, Zane Voss, Jeffrey D. Smith, Ronald J. O'Malley, Rex E. Gerald, Jie Huang
Electrical and Computer Engineering Faculty Research & Creative Works
The bottom anode in the Direct Current Electric Arc Furnace (DC EAF) is critical for completing the electrical circuit necessary for sustaining the arc within the furnace. For pin-type bottom anodes, monitoring of the temperature of select pins instrumented with thermocouples is performed to track bottom wear in the EAF and inform the operator when the furnace should be removed from service. This work presents the results from a plant trial using distributed temperature monitoring of bottom anode pins in a 165-ton DC EAF over a two-month service period utilizing two optical fiber sensing techniques: fiber Bragg grating (FBG) and …
Discrimination Of Temperature And Strain By Characterizing Two Femtosecond Laser-Written Coincident Sapphire Fiber Bragg Gratings For Harsh Environment Applications, Farhan Mumtaz, Bohong Zhang, Koustav Dey, Jeffrey D. Smith, Ronald J. O'Malley, Jie Huang
Discrimination Of Temperature And Strain By Characterizing Two Femtosecond Laser-Written Coincident Sapphire Fiber Bragg Gratings For Harsh Environment Applications, Farhan Mumtaz, Bohong Zhang, Koustav Dey, Jeffrey D. Smith, Ronald J. O'Malley, Jie Huang
Electrical and Computer Engineering Faculty Research & Creative Works
In this study, two co-incident sapphire fiber Bragg gratings (SFBGs) were successfully inscribed utilizing a femtosecond (fs) laser to achieve a high fringe contrast interferogram. These two SFBGs employ a unique configuration, one parallel to the center axis, called p-SFBG, and the other forming an angle from the center-axis, called a-SFBG, allowing for simultaneous strain and temperature measurements with low crosstalk. As a proof of concept, p-SFBG and a-SFBG using line-by-line method are characterized, which are shorter in length (i.e., 1.5 mm), producing reflectivity of ~3dB. This effort demonstrates the use of two coincident SFBGs forming an angle of 2.29° …
The Structure, Properties And Dissolution Behaviors Of Phosphate Glasses, Han Zhang
The Structure, Properties And Dissolution Behaviors Of Phosphate Glasses, Han Zhang
Doctoral Dissertations
The poor chemical durability remains a critical challenge for the application of phosphate glasses. This study investigates the compositional influences on the structure, properties and chemical durability of Li2O-ZnO-P2O5 glasses. Their structural characteristics were analyzed utilizing high-performance liquid chromatography, Raman spectroscopy, and X-ray photoelectron spectroscopy. The incorporation of (Li2O+ZnO) in LZeq glasses depolymerizes the phosphate network. In LZ40P and LZ45P glasses, Li+ initially replaces Zn2+ associated with non-bridging oxygens (NBOs) in Q2 tetrahedra. Once the substitution in Q2 is complete, further Li⁺ incorporation leads to the replacement of Zn2+ in Q1 …
Investigating The Effects Of Fly Ash On The Properties Of Silica-Deficient High Alumina Materials, Sai Akshay Ponduru
Investigating The Effects Of Fly Ash On The Properties Of Silica-Deficient High Alumina Materials, Sai Akshay Ponduru
Doctoral Dissertations
This research is made up of five studies mainly focused on attaining sustainability in high alumina cements like calcium aluminate cement (CAC) and calcium sulfoaluminate belite cements (CSAB) by partially replacing them with additives and supplementary cementitious materials (SCMs) like fly ash (FA). The first study focused on understanding the reaction kinetics of CAC and FA binders at different replacement levels (i.e. between 10%-to-50% by mass) and their effect on mechanical properties. It was also shown that the reactive nature of FAs can be determined by calculating a single parameter called number of constraints (nc) derived from topological constraint theory. …
High-Frequency Gold Price Forecasting: Optimizing Multi-Layer Perceptron With Genetic Algorithm, Vrtagic Sabahudin, Fatih Dogan
High-Frequency Gold Price Forecasting: Optimizing Multi-Layer Perceptron With Genetic Algorithm, Vrtagic Sabahudin, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
Accurately forecasting gold price actions is critical in financial markets due to gold's role as a safe-haven asset. This paper addresses the challenge of forecasting gold prices by applying a Genetic Algorithm (GA) with a Multi-Layer Perceptron (MLP) model. The research exploits historical financial data from various instruments, including gold futures, Bitcoin, and key currency pairs, to improve prediction accuracy. By optimizing the MLP's hyper parameters through GA, the model efficiently captures complex relationships in high-frequency data, achieving a remarkable R² score of 0.9993. This level of precision demonstrates the model's potential for providing actionable insights for traders and investors. …
Estimating The Possible Qpos Of M87* From The Parameters Of A Hairy Kerr Black Hole, Orhan Donmez, Fatih Dogan
Estimating The Possible Qpos Of M87* From The Parameters Of A Hairy Kerr Black Hole, Orhan Donmez, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
In this paper, we study the dynamics of the shock cone formed around a hairy Kerr black hole due to Bondi– Hoyle–Lyttleton (BHL) accretion and investigate the quasi-periodic oscillations (QPO) behaviors resulting from the black hole-cone interaction, aiming to predict the QPO frequencies that may occur around the M87∗ black hole. To achieve this, we use the hairy Kerr black hole parameters consistent with the observed shadow parameters of M87∗ as initial conditions in numerical simulations, revealing the structure of the resulting shock cone and QPOs in a strong gravitational field. Numerical calculations show that the deviation of …
Hafnium Oxide Coating To Improve The Oxidation Behavior Of Zirconium Diboride, Jan E. Förster, William G. Fahrenholtz, Gregory E. Hilmas, Ravisankar Naraparaju
Hafnium Oxide Coating To Improve The Oxidation Behavior Of Zirconium Diboride, Jan E. Förster, William G. Fahrenholtz, Gregory E. Hilmas, Ravisankar Naraparaju
Materials Science and Engineering Faculty Research & Creative Works
Hafnium dioxide (HfO2) coatings were successfully deposited on zirconium diboride (ZrB2) using reactive magnetron sputtering. After the oxidation at 1500°C or 1600°C, the mutual dissolution of HfO2 and thermally grown ZrO2 was observed which has resulted in the formation of a mixed oxide zone. As the enrichment of the mixed oxide zone by ZrO2 progresses, monoclinic/tetragonal phase transition temperature of ∼1790°C for nominally pure HfO2 moves towards ∼1500 °C. Finally, the inevitable phase transition from monoclinic to tetragonal structure results in the development of cracks, pores, and gaps within the mixed oxide …
Machine Learned Interatomic Potentials For Ternary Carbides Trained On The Aflow Database, Josiah Roberts, Biswas Rijal, Simon Divilov, Jon Paul Maria, William G. Fahrenholtz, Douglas E. Wolfe, Donald W. Brenner, Stefano Curtarolo, Eva Zurek
Machine Learned Interatomic Potentials For Ternary Carbides Trained On The Aflow Database, Josiah Roberts, Biswas Rijal, Simon Divilov, Jon Paul Maria, William G. Fahrenholtz, Douglas E. Wolfe, Donald W. Brenner, Stefano Curtarolo, Eva Zurek
Materials Science and Engineering Faculty Research & Creative Works
Large-density functional theory (DFT) databases are a treasure trove of energies, forces, and stresses that can be used to train machine-learned interatomic potentials for atomistic modeling. Herein, we employ structural relaxations from the AFLOW database to train moment tensor potentials (MTPs) for four carbide systems: CHfTa, CHfZr, CMoW, and CTaTi. The resulting MTPs are used to relax ~6300 random symmetric structures and are subsequently improved via active learning to generate robust potentials (RP) that can relax a wide variety of structures, and accurate potentials (AP) designed for the relaxation of low-energy systems. This protocol is shown to yield convex hulls …
Synthesis And Properties Of (Hf,Mo,Ti,W,Zr)B2–(Hf,Mo,Ti,W,Zr)C Dual Phase Ceramics, S. Filipović, S. M. Smith, G. Hilmas, W. Fahrenholtz, N. Obradović, S. Curtarolo
Synthesis And Properties Of (Hf,Mo,Ti,W,Zr)B2–(Hf,Mo,Ti,W,Zr)C Dual Phase Ceramics, S. Filipović, S. M. Smith, G. Hilmas, W. Fahrenholtz, N. Obradović, S. Curtarolo
Materials Science and Engineering Faculty Research & Creative Works
Dense, dual phase (Hf,Mo,Ti,W,Zr)B2–(Hf,Mo,Ti,W,Zr)C ceramics were synthesized with varying contents of Mo and W. The final (Hf0.317Mo0.025Ti0.317W0.025Zr0.317)C–(Hf0.317Mo0.025Ti0.317W0.025Zr0.317)B2 was a nominally pure, dual phase ceramic, while compositions with higher amounts of Mo and W contained multiple phases. The final microstructures had submicron grains due to pinning effects. Vickers hardness values were up to 48.6 ± 2.2 GPa for an applied load of 0.49 N for the ceramic with optimized composition and densification. The solubility limits for Mo and …
Impact Of Tib2 Source On The Microstructure And Properties Of Tib2–Sic–B4c Ceramics, Steven M. Smith, Suzana Filipovic, William G. Fahrenholtz, Gregory E. Hilmas, Carlo Baldisserri, Laura Silvestroni
Impact Of Tib2 Source On The Microstructure And Properties Of Tib2–Sic–B4c Ceramics, Steven M. Smith, Suzana Filipovic, William G. Fahrenholtz, Gregory E. Hilmas, Carlo Baldisserri, Laura Silvestroni
Materials Science and Engineering Faculty Research & Creative Works
To date, the thermal and electrical properties of three-phase ceramics containing a boride phase, silicon carbide, and boron carbide have not been studied in detail. Further, the effect of the source of the boride powder has also not been investigated. This study produced three-phase ceramics containing titanium diboride, silicon carbide, and boron carbide using three different TiB2 sources: commercial powder, TiB2 synthesized by boro/carbothermal reduction, or (Ti,Cr)B2 synthesized by boro/carbothermal reduction to address the effect of the TiB2 source. Ceramics containing synthesized TiB2 or (Ti,Cr)B2 reached >99% relative density, while the ceramic produced from …
Kinetic Modeling Of Dust Grain Dynamics In Electrostatic Sieving, Aaron Berkhoff, Easton Ingram, Fateme Rezaei, Jeffrey Smith, David Bayless, William Schonberg, Daoru Han
Kinetic Modeling Of Dust Grain Dynamics In Electrostatic Sieving, Aaron Berkhoff, Easton Ingram, Fateme Rezaei, Jeffrey Smith, David Bayless, William Schonberg, Daoru Han
Chemical and Biochemical Engineering Faculty Research & Creative Works
A new kinetic particle modeling framework was developed to investigate electrostatic transport of lunar regolith dust particles with applications to the concept of electrostatic sieving. the new approach is based on kinetic particle dynamics and includes major modules of sampling the particle size distribution, solving electric fields, and tracking motion of charged dust grains. a case study for a concept of electrostatic sieving was chosen to validate the new model. the simulation achieved similar performance of particle size classification as reported in the literature. the new model is computationally efficient (takes a few minutes on a PC-type laptop computer) so …
Response Of ¹¹B Enriched Zrb2 Ultra-High Temperature Ceramic To Neutron Irradiation At Elevated Temperatures, Yan Ru Lin, Takaaki Koyanagi, David J. Sprouster, Christian M. Petrie, William Fahrenholtz, Greg Hilmas, Yutai Katoh
Response Of ¹¹B Enriched Zrb2 Ultra-High Temperature Ceramic To Neutron Irradiation At Elevated Temperatures, Yan Ru Lin, Takaaki Koyanagi, David J. Sprouster, Christian M. Petrie, William Fahrenholtz, Greg Hilmas, Yutai Katoh
Materials Science and Engineering Faculty Research & Creative Works
ZrB2, an ultra-high temperature ceramic (UHTC) is being considered for use in fusion reactor first-wall structures, yet its response to irradiation remains poorly understood. This study employed scanning/transmission electron microscopy (S/TEM), synchrotron X-ray diffraction (XRD), finite element calculations, and thermal property measurements to thoroughly investigate the neutron-irradiation effects on 11B-enriched ZrB2. Neutron irradiations were conducted at 220 °C and 620 °C, with a neutron fluence of 2.2 x 1025 neutron/m2 (energy > 0.1 MeV), resulting in 3.9 dpa and 4200 appm He. The study revealed the unusual prevalence of prism loops and a > c anisotropic lattice …
Hardness Of Single Phase High Entropy Carbide Ceramics With Different Compositions, Paul M. Brune, Gregory E. Hilmas, William G. Fahrenholtz, Jeremy Lee Watts, Caillin J. Ryan, Chris M. Desalle, Douglas E. Wolfe, Stefano Curtarolo
Hardness Of Single Phase High Entropy Carbide Ceramics With Different Compositions, Paul M. Brune, Gregory E. Hilmas, William G. Fahrenholtz, Jeremy Lee Watts, Caillin J. Ryan, Chris M. Desalle, Douglas E. Wolfe, Stefano Curtarolo
Materials Science and Engineering Faculty Research & Creative Works
Five High Entropy Carbide Ceramics, (Hf0.2,Nb0.2,Ta0.2,Ti0.2,Zr0.2)C, (Cr0.2,Hf0.2,Ta0.2,Ti0.2,Zr0.2)C, (Hf0.2,Mo0.2,Ta0.2,Ti0.2,Zr0.2)C, (Hf0.2,Ta0.2,Ti0.2,W0.2,Zr0.2)C, and (Hf0.2,Mo0.2,Ti0.2,W0.2,Zr0.2)C, Were Synthesized by Carbothermal Reduction of Oxides and Direct Current Sintering. the Five High Entropy Carbide Ceramics Were Determined to Be Nominally Phase-Pure with Relative Densities of More Than 98.9% and Mean Grain Sizes of Less Than 5 Μm. Average Vickers Hardness Values Ranged from 19.2 ± 0.4 GPa for (Hf0.2,Nb0.2,Ta0.2,Ti0.2,Zr0.2)C at a Load of 2 Kgf to 43.5 ± 0.4 GPa for (Hf0.2,Mo0.2,Ti0.2,W0.2,Zr0.2)C at a Load of 0.05 Kgf. Hardness Generally Increased with Increasing the Valence Electron Concentration and Strain as Measured by the Williamson-Hall Analysis. However, Neither …
Effect Of The Filler Morphology On The Crystallization Behavior And Dielectric Properties Of The Polyvinylidene Fluoride-Based Composite, Suzana Filipović, Nina Obradović, Cole Corlett, William G. Fahrenholtz, Martin Rosenschon, Ekkehard Füglein, Radovan Dojčilović, Dragana Tošić, Jovana Petrović, Antonije Đorđević, Branislav Vlahović, Vladimir B. Pavlović
Effect Of The Filler Morphology On The Crystallization Behavior And Dielectric Properties Of The Polyvinylidene Fluoride-Based Composite, Suzana Filipović, Nina Obradović, Cole Corlett, William G. Fahrenholtz, Martin Rosenschon, Ekkehard Füglein, Radovan Dojčilović, Dragana Tošić, Jovana Petrović, Antonije Đorđević, Branislav Vlahović, Vladimir B. Pavlović
Materials Science and Engineering Faculty Research & Creative Works
Ceramic/polymer composites can be chemically stable, mechanically strong, and flexible, which make them candidates for electric devices, such as pressure or temperature sensors, energy storage or harvesting devices, actuators, and so forth. Depending on the application, various electrical properties are of importance. Polymers usually have low dielectric permittivity, but increased dielectric permittivity can be achieved by the addition of the ceramic fillers with high dielectric constant. With the aim to enhance dielectric properties of the composite without loss of flexibility, 5 wt.% of BaTiO3-Fe2O3 powder was added into a polyvinylidene fluoride matrix. The powder was …
Dielectric Properties Of Polycrystalline And Single-Crystal Magnesium Oxide At High Temperatures, Alan Devoe, Hung Trinh, Fatih Dogan
Dielectric Properties Of Polycrystalline And Single-Crystal Magnesium Oxide At High Temperatures, Alan Devoe, Hung Trinh, Fatih Dogan
Materials Science and Engineering Faculty Research & Creative Works
The electrical properties of high-purity magnesium oxide (MgO) samples sintered between 1500 and 1650°C were investigated up to 800°C. Dielectric constant, loss tangent and electrical conductivity were measured between 25 and 800°C. Optimum electrical properties were obtained for the sample sintered at 1600°C. The impurities in polycrystalline and single crystal MgO were discussed to understand their effect on electrical properties and the role of grain boundaries. Higher dielectric losses of polycrystalline samples as compared to the single crystal MgO were attributed to the presence of grain boundaries. MgO could be a useful dielectric material for capacitor applications up to 600°C.