Degradation Of Radioactive Waste Encapsulation Of Bao−Feox−P2o5 Glass Evaluated From Electrical Conductivity,
2025
Missouri University of Science and Technology
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 …
Understanding Heterogeneous Nucleation In Iron Alloys From First Principles: A Review And Discussion,
2025
Missouri University of Science and Technology
Understanding Heterogeneous Nucleation In Iron Alloys From First Principles: A Review And Discussion, Semen Naumovich Lekakh
Materials Science and Engineering Faculty Research & Creative Works
Heterogeneous nucleation during solidification plays a key role in structure formation of different types of iron-based alloys, including steels and cast irons. A review summarizes the novel theoretical methods which were used to understand the nature of heterogeneous nucleation in iron-based alloys. An ab initio simulation of atomic adsorption was used to predict the activity of heterogeneous nuclei, and the thermodynamic methods were applied to design conditions for desired precipitate formation in the iron melts. A high-resolution TEM study of individual nucleus and statistics of nuclei family, obtained from an automated SEM/EDX analysis, illustrates a possibility to design processes of …
Designing Robust Quasi-2d Perovskites Thin Films For Stable Light-Emitting Applications,
2025
Missouri University of Science and Technology
Designing Robust Quasi-2d Perovskites Thin Films For Stable Light-Emitting Applications, Sharmistha Khan, Reshna Shrestha, Mengru Jin, Doyun Kim, Guan Lin Chen, Ruipeng Li, Yijia Gu, Qing Tu, Namyoung Ahn, Wanyi Nie
Materials Science and Engineering Faculty Research & Creative Works
Quasi-2D perovskite made with organic spacers co-crystallized with inorganic cesium lead bromide inorganics is demonstrated for near unity photoluminescence quantum yield at room temperature. However, light emitting diodes made with quasi-2D perovskites rapidly degrade which remains a major bottleneck in this field. In this work, It is shown that the bright emission originates from finely tuned multi-component 2D nano-crystalline phases that are thermodynamically unstable. The bright emission is extremely sensitive to external stimuli and the emission quickly dims away upon heating. After a detailed analysis of their optical and morphological properties, the degradation is attributed to 2D phase redistribution associated …
Ground Testing Of A Magnetic-Electrostatic Separation System For Lunar Regolith Beneficiation,
2025
Missouri University of Science and Technology
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 …
The Effect Of Carbon Equivalent And Nodularity On Multi-Axial Casting Wall Movement During Spheroidal Graphite Iron Solidification And Cooling,
2025
Missouri University of Science and Technology
The Effect Of Carbon Equivalent And Nodularity On Multi-Axial Casting Wall Movement During Spheroidal Graphite Iron Solidification And Cooling, Noah J. Brack, Mingzhi Xu, Jingjing Qing, Simon Lekakh
Materials Science and Engineering Faculty Research & Creative Works
Spheroidal graphite iron, also known as ductile iron, is an iron–carbon casting alloy used in industry for its good castability, balanced mechanical properties, and low cost. Ductile iron consists of round graphite nodules in an iron matrix. During solidification and cooling, ductile iron castings experience dynamic volume changes due to the precipitation of graphite nodules and formation of austenite. These dynamic volume changes can distort external casting surfaces, causing swell and shrinkage porosity. A novel apparatus was custom-built to capture the casting wall movement in real time along three axes. This study found that casting expansion increased with carbon equivalent …
Controlling Nitrogen Pickup During Induction Melting Of Ultrahigh-Strength Cr-Ni-Mo-V Steels,
2025
Missouri University of Science and Technology
Controlling Nitrogen Pickup During Induction Melting Of Ultrahigh-Strength Cr-Ni-Mo-V Steels, Kingsley T. Amatanweze, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field
Materials Science and Engineering Faculty Research & Creative Works
Nitrogen pickup during air induction melting can result in porosity and a loss of fracture toughness in ultrahigh-strength quenched and tempered steel castings. Nitrogen atoms are easily adsorbed into liquid steel upon exposure to the air, and argon shrouding alone has limited effectiveness. Previous studies have shown that proper charge sequencing and maintaining a high amount of dissolved oxygen in the melt prior to tapping and deoxidation can limit nitrogen pickup in the melt. In the current study, the effect of melt practice and charging procedure on nitrogen pickup was studied as a function of hold time in a series …
A Novel Technique For Improved Measurement Of Graphite And Inclusions In Ductile Iron Contaminated By Boron,
2025
Missouri University of Science and Technology
A Novel Technique For Improved Measurement Of Graphite And Inclusions In Ductile Iron Contaminated By Boron, Chase Schroeder, Colleen Lehrer, Simon Lekakh, Laura Bartlett
Materials Science and Engineering Faculty Research & Creative Works
The highly heterogeneous microstructure of ductile iron in casting includes graphite particles, non-metallic inclusions, microporosity, and other features, such as carbides distributed in the ferrite–pearlite matrix. Determination and comprehensive quantification of microstructural features are practically important however challenging. An advanced methodology based on an automated SEM/EDX analysis was developed and compared to the standard optical imaging method. In addition to backscattered electron contrast, sensitive to atomic number, a novel methodology added EDX data to identify and classify the multiple structural features at micron resolution thresholding. To quantify the shape of individual phases, the eight chord raster algorithms was used and …
Zrc Particle Size Effect On The Mechanical Properties Of Spark Plasma Sintered 60–40 Vol% Zrc–Mo Cermets,
2025
Missouri University of Science and Technology
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 …
Effect Of Gating Design On Filling And Inclusion Control In An Al-Killed Cr-Mo-Ni Steel,
2025
Missouri University of Science and Technology
Effect Of Gating Design On Filling And Inclusion Control In An Al-Killed Cr-Mo-Ni Steel, Kingsley T. Amatanweze, Koushik Balasubramanian, Soumava Chakraborty, Viraj A. Athavale, Mario F. Buchely, Laura N. Bartlett, Ronald J. O'Malley, Daniel M. Field, Krista R. Limmer, Katherine M. Sebeck
Materials Science and Engineering Faculty Research & Creative Works
The effect of gating system design on the inclusion population and size distribution in an aluminum-killed low-alloy advanced high strength steel casting was studied. A mold with four different gating systems: pressurized and non-pressurized with side risers, naturally pressurized with a side riser, and naturally pressurized with a top riser, was designed using computational fluid dynamics and solidification software. The design allowed inclusion populations in castings produced with each gating system to be compared during the same pouring event. Samples taken from different positions just below the top surface of each casting were analyzed using an SEM/EDS system with automated …
Parametric Analysis Of Water Jet Descaling Efficiency Of Reheated Continuously Cast Thin Slab,
2025
Missouri University of Science and Technology
Parametric Analysis Of Water Jet Descaling Efficiency Of Reheated Continuously Cast Thin Slab, Tochukwu P. Ojiako, Mario F. Buchely, Simon Lekakh, Ronald J. O'Malley, Richard Osei, Taha Tayebali
Materials Science and Engineering Faculty Research & Creative Works
Efficient oxide scale removal is critical for maintaining surface quality and process efficiency in steel manufacturing. This study optimizes water jet descaling by evaluating the performance of flat and rotary jet nozzles under varying process parameters. Using a combined approach of experimental analysis and computational fluid dynamics, it investigates the influence of pressure (138–275 bar), lead angle (0°, 15°, 25°), working distance (50–100 mm), and spray angle (15°–25°) on descaling efficiency. Findings indicate that flat jet nozzles achieve superior performance at short working distances due to concentrated impact forces, while rotary jet nozzles sustain efficiency over extended distances through dynamic …
High-Temperature Performance Of Alloyed Cast Irons And Cr/Ni Austenitic Steels—An Overview And Discussion,
2025
Missouri University of Science and Technology
High-Temperature Performance Of Alloyed Cast Irons And Cr/Ni Austenitic Steels—An Overview And Discussion, Simon N. Lekakh, Mei Li, Larry Godlewski
Materials Science and Engineering Faculty Research & Creative Works
Fe-based cast alloys, including cast irons and steels, have been used in service at a wide range of mechanical and thermal load in oxidizing environment. Special alloying practices can be used to improve high temperature performance of Fe-based cast alloys in an oxidizing atmosphere. At elevated temperatures, alloying elements can produce a protective interface layer which prevents oxidant penetration into the metal matrix. However, a combination of thermo-mechanical loads along with surface oxidation can decrease the materials integrity by destroying the stable protected interface limiting the range of working parameters and lifetime performance of the material. This overview aims to …
Flexural Strength Of (Hf,Nb,Ta,Ti,Zr)B2–(Hf,Nb,Ta,Ti,Zr)C High-Entropy Dual-Phase Ceramics,
2025
Missouri University of Science and Technology
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 …
Mechanical And Thermal Characterization Of Additively Manufactured Carbon/Nylon 12 And Carbon/Peek Composites,
2025
Missouri University of Science and Technology
Mechanical And Thermal Characterization Of Additively Manufactured Carbon/Nylon 12 And Carbon/Peek Composites, Matik Heskin, Bradley Deuser, Thomas P. Schuman, K. Chandrashekhara, John Bayldon, Jeff Degrange, Steven Patterson, Neiko Levenhagen
Chemistry Faculty Research & Creative Works
This study explores additive manufacturing of carbon fiber-reinforced thermoplastic composites using the Composite-Based Additive Manufacturing (CBAM) process. Carbon/Nylon 12 and Carbon/PEEK composites were fabricated and evaluated through mechanical (compression, tensile, flexural, and impact) and thermal (DSC and TGA) tests. Carbon/PEEK exhibited superior mechanical performance, with 97.5% higher tensile strength, 79.8% higher elastic modulus, and 59.6% higher flexural strength compared to Carbon/Nylon 12. Thermal testing showed that Carbon/PEEK had higher thermal stability, beginning degradation at 350 °C versus 298 °C for Carbon/Nylon. These results indicate that CBAM-fabricated Carbon/PEEK composites are suitable for applications requiring high strength and temperature resistance.
Molecular Dynamics Simulations Of Key Parameters On Thermal Properties Of Carbon Nanotube Modified Epoxy Composites,
2025
South Dakota State University
Molecular Dynamics Simulations Of Key Parameters On Thermal Properties Of Carbon Nanotube Modified Epoxy Composites, Lida Najmi
Electronic Theses and Dissertations
The application of carbon nanotube (CNT)-reinforced epoxy matrix composites (CRECs) has attracted extensive attention in various industrial sectors due to the significant improvement of material properties imparted by CNTs. The thermal behavior of these nanocomposites is governed by complex heat transfer mechanisms operating at different scales, resulting in a complex relationship between the effective thermal response and the microstructural characteristics of the composite. In this study, molecular dynamics (MD) simulations were used to investigate the thermal conductivity of CRECs, focusing on the effects of key parameters such as the length and volume fraction of CNTs, the degree of cross-linking within …
A Comprehensive Review Of Piezoelectric Pvdf Polymer Fabrications And Characteristics,
2025
Old Dominion University
A Comprehensive Review Of Piezoelectric Pvdf Polymer Fabrications And Characteristics, Nadia Ahbab, Sidra Naz, Tian-Bing Xu, Shihai Zhang
Mechanical & Aerospace Engineering Faculty Publications
Polyvinylidene fluoride (PVDF) polymer films, renowned for their exceptional piezoelectric, pyroelectric, and ferroelectric properties, offer a versatile platform for the development of cutting-edge micro-scale functional devices, enabling innovative applications ranging from energy harvesting and sensing to medical diagnostics and actuation. This paper presents an in-depth review of the material properties, fabrication methodologies, and characterization of PVDF films. Initially, a comprehensive description of the physical, mechanical, chemical, thermal, electrical, and electromechanical properties is provided. The unique combination of piezoelectric, pyroelectric, and ferroelectric properties, coupled with its excellent chemical resistance and mechanical strength, makes PVDF a highly valuable material for a wide …
Design Of Aluminum-Copper Alloy With Scandium In Solution,
2025
Michigan Technological University
Design Of Aluminum-Copper Alloy With Scandium In Solution, Austin M. Depottey
Dissertations, Master's Theses and Master's Reports
The 2xxx series of precipitation-strengthened aluminum-copper alloys are commonly used in high-temperature applications (up to 300°C) where lightweight metals are required. Scandium additions to aluminum-copper alloys have gained recent academic interest due to improved high-temperature mechanical properties, by forming coarsening- resistant Al3Sc dispersoids and stabilization of θ′ precipitates. However, gaps in knowledge about the effects of scandium present a challenge to successful commercialization of aluminum-copper-scandium alloys. This work seeks to explore these knowledge gaps and ultimately design and test a commercially feasible aluminum- copper alloy with scandium. To better understand the processing conditions required to avoid the detrimental W-phase (Al8Cu4Sc), …
Machine Learning Design And Experimental Production Of Recycled Aluminum Alloys With Magnesium And Iron,
2025
Michigan Technological University
Machine Learning Design And Experimental Production Of Recycled Aluminum Alloys With Magnesium And Iron, Skylar Patten
Dissertations, Master's Theses and Master's Reports
Recycling aluminum saves up to 95% of the energy required for primary production but introduces impurities such as iron that limit alloy performance. The Al-Mg-Fe system, though commercially used, remains underexplored. This work applies machine learning with Multi-Objective Bayesian Optimization (MOBO) using Thermo-Calc simulations to design Al-Mg-Fe-Si-Cu-Zn alloys with improved castability and reduced porosity. The optimization targeted freezing range, shrinkage, drag coefficient, and microstructural parameters, identifying compositions with high Mg, Si, and Cu and low Zn as optimal. Predicted alloys were experimentally cast and characterized, with yield strengths exceeding 95 MPa and elongation comparable to commercial 319 aluminum in the …
Electrochemical And Nanomaterial Based Strategies For Nonenzymatic Glucose Detection: A Review,
2025
Old Dominion University
Electrochemical And Nanomaterial Based Strategies For Nonenzymatic Glucose Detection: A Review, Reagan Aviha, Gymama Slaughter
Center for Bioelectronics Publications
Electrochemical glucose sensing technologies have undergone significant evolution, with continual advancements aimed at improving sensitivity, selectivity, and user convenience. This review systematically explores the development of emerging nonenzymatic glucose sensor designs. Nonenzymatic sensors are critically evaluated for their ability to overcome enzymatic limitations, leveraging novel materials and catalytic mechanisms. Additionally, the emergence of smartphone-integrated glucose monitoring systems is highlighted as the fifth generation, representing a paradigm shift toward personalized, real-time healthcare management. Emphasis is placed on the strategies employed to reduce the working electrode potential and enhance analytical performance. Key analytical metrics and real-sample applicability are evaluated, and persistent challenges …
Nanomaterial-Enabled Enhancements In Thylakoid-Based Biofuel Cells,
2025
Old Dominion University
Nanomaterial-Enabled Enhancements In Thylakoid-Based Biofuel Cells, Amit Sarode, Gymama Slaughter
Center for Bioelectronics Publications
Thylakoid-based photosynthetic biofuel cells (TBFCs) harness the inherent light-driven electron transfer pathways of photosynthesis to enable sustainable solar-to-electrical energy conversion. While TBFCs offer a unique route toward biohybrid energy systems, their practical deployment is hindered by sluggish electron transfer kinetics, unstable redox mediators, and inefficient interfacing between biological and electrode components. This review critically examines recent advances in TBFCs, with a focus on three key surface engineering strategies: (i) incorporation of nanostructured materials to enhance electrode conductivity and surface area; (ii) application of redox mediators to facilitate charge transfer between photosynthetic proteins and electrodes; and (iii) functional exploitation of individual …
Thermo-Rheological And Tribological Properties Of Low- And High-Oleic Vegetable Oils As Sustainable Bio-Based Lubricants,
2025
Missouri University of Science and Technology
Thermo-Rheological And Tribological Properties Of Low- And High-Oleic Vegetable Oils As Sustainable Bio-Based Lubricants, Abiodun Saka, Tobechukwu K. Abor, Anthony C. Okafor, Monday U. Okoronkwo
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Vegetable oil-based lubricants have attracted increased research attention in recent decades as sustainable alternatives to conventional petroleum-based lubricants in metal machining. However, more studies are required to fully elucidate the thermo-rheological and tribological properties. This study presents an investigation of the thermo-rheological and tribological properties of different vegetable oils, including low- and high-oleic soybean oil, high-oleic sunflower, safflower, and canola oils. The lubricity, and evolution of viscosity and thermodynamic properties as a function of temperature were investigated to obtain important parameters including the viscosity index, flow behavior index, flow activation energy, specific heat capacity, thermal conductivity, coefficient of friction, contact …
