Materials Science and Engineering Commons^™

Anisotropic Thermal Expansion In High-Entropy Multicomponent Alb2-Type Diboride Solid Solutions, Frédéric Monteverde, Mattia Gaboardi, Federico Saraga, Lun Feng, William Fahrenholtz, Gregory Hilmas

Materials Science and Engineering Faculty Research & Creative Works

High-entropy (HE) ultra-high temperature ceramics have the chance to pave the way for future applications propelling technology advantages in the fields of energy conversion and extreme environmental shielding. Among others, HE diborides stand out owing to their intrinsic anisotropic layered structure and ability to withstand ultra-high temperatures. Herein, we employed in-situ high-resolution synchrotron diffraction over a plethora of multicomponent compositions, with four to seven transition metals, with the intent of understanding the thermal lattice expansion following different composition or synthesis process. As a result, we were able to control the average thermal expansion (TE) from 1.3 x 10−6 to 6.9 …

Anisotropic Thermal Expansion In High-Entropy Multicomponent Alb2-Type Diboride Solid Solutions, Frédéric Monteverde, Mattia Gaboardi, Federico Saraga, Lun Feng, William Fahrenholtz, Gregory Hilmas

Mathematics and Statistics Faculty Research & Creative Works

High-entropy (HE) ultra-high temperature ceramics have the chance to pave the way for future applications propelling technology advantages in the fields of energy conversion and extreme environmental shielding. Among others, HE diborides stand out owing to their intrinsic anisotropic layered structure and ability to withstand ultra-high temperatures. Herein, we employed in-situ high-resolution synchrotron diffraction over a plethora of multicomponent compositions, with four to seven transition metals, with the intent of understanding the thermal lattice expansion following different composition or synthesis process. As a result, we were able to control the average thermal expansion (TE) from 1.3 x 10−6 to 6.9 …

Particle Migration In Large Cross-Section Ceramic On-Demand Extrusion Components, Austin J. Martin, Wenbin Li, Jeremy Lee Watts, Gregory E. Hilmas, Ming-Chuan Leu, Tieshu Huang

Mathematics and Statistics Faculty Research & Creative Works

Ceramic On-Demand Extrusion (CODE) is a direct ink writing process which allows for the creation of near theoretically dense ceramic components with large cross-sections due to oil-assisted drying. Yttria-stabilized zirconia (YSZ) colloidal pastes (∼d50 ≲ 1 µm) were used in CODE to produce dense (multi-road infill and ≳ 98% relative density), large continuous volume (> 1 cm3), and high fidelity (nozzle diameters ≲ 1 mm) structural ceramic components. However, many of these printed components underwent significant particle migration after forming. The reason for this particle migration defect was investigated using the coffee-ring effect for dilute solutions and rheological methods for …

Experimental And Computational Bearing Strength Of Fiber Metal Laminate With And Without Film Adhesive, Christopher L. Bellanova Jr.

Theses and Dissertations

This research characterized the performance of a fiber metal laminate composed of carbon fiber and stainless steel without film adhesive and compared it to a similar, previously tested, fiber metal laminate including film adhesive. Removal of the adhesive layers reduced the localized thickness, simplified manufacturing, and allowed for a 20% increase in foil thickness. Quasi-static testing was conducted in double shear, single shear protruding, and single shear countersunk configurations. The results were compared to adhesive hybrid and control samples. To study the affects of bolt tension, samples at low torque in double shear were also tested. Progressive failure samples revealed …

Anisotropic Characterization Of Additively Manufactured Ti 6-4 Via Tension, Compression, And Three Point Bend Experimentation, James M. Gunderson

Theses and Dissertations

Titanium's ability to fill existing material gaps because of its higher strength and higher melting temperature compared to other common materials used in aircraft structures requires a need to understand the behavior of the material. Titanium's properties and the development of additive manufacturing also open an opportunity for it to be used in aerospace systems of the future in applications where traditionally manufactured titanium cannot meet the desired system requirements. Compressive, tensile, and three point bend experimental data collected from this research under varying temperatures, print orientations, print layer build heights, and surface finishes were analyzed to determine favorable material …

Development Of Novel Turbomachinery Manufacturing Methods, Timothy P. Winkler

Theses and Dissertations

Compact turbine engines are of increasing interest as a means of propulsion for small, lightweight, low cost, unmanned aerial systems. This study looks to leverage advancements in novel manufacturing technology to produce turbomachinery components while simultaneously reducing costs and manufacturing time. To determine the feasibility of drop-in replacements for stock components this study focused on several research areas. This included materials research on both polymer-reinforced and ceramic materials, specimen tensile testing to determine temperature-dependent material properties, finite element analysis of multiple candidate materials, design and fabrication of a spin test rig, and physical spin testing of manufactured components to predict …

Characterizing Gesn Alloys By Sem/Eds And Photoluminescence Spectroscopy, Christopher M. Sutphin

Theses and Dissertations

Germanium tin (GeSn) alloys are being studied as potential transition metal (Group IV) photoelectric semiconductors or optical detectors. GeSn alloys could be employed as an optically active material within a computer. Compared to current technologies, a direct band gap GeSn alloy can be engineered to operate with higher thermal stability and efficiency. The GeSn alloy studied was composed of Ge and Si substrates with various Sn percentages grown using remote plasma-enhanced chemical vapor deposition (RPECVD). Photoluminescence spectroscopy (PL) techniques were initially used to determine the GeSn properties, including the band gap. The Ge_91.2Sn_8.8 PL spectra suggested the …

Recent Advances In Anode Materials Of Solid Oxide Electrolysis Cells, Geng Zou, Wei-Cheng Feng, Yue-Feng Song, Guo-Xiong Wang

Journal of Electrochemistry

Solid oxide electrolysis cell (SOEC) as an electrochemical energy conversion device has attracted increasing attention due to its large current density, high Faradaic efficiency and energy efficiency. Oxygen evolution reaction at the anode, a four-electron transfer process, is an important half-reaction for SOEC, which contributes to the main polarization resistance and consumes most electric energy during the electrolysis process. Hence, designing anode materials with high activity and stability is crucial for the performance improvement and practical application of SOEC. Recently, some advances have been made in the development of high-performance anode. In the current review, the mechanisms for CO_{2 …}

Advances And Challenges On Cathode Catalysts For Lithium-Oxygen Batteries, Bo Wen, Zhuo Zhu, Fu-Jun Li

Journal of Electrochemistry

Aprotic lithium-oxygen batteries (LOBs) with high theoretical energy density have received considerable attention over the past years. However, the oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) at cathodes suffer from slow kinetics for large overvoltages in LOBs. Significant advances on catalysts have been achieved to accelerate cathode kinetics, but understanding on the formation/decomposition processes of Li₂O₂ is limited. Herein, this review highlights the fundamental understanding of the correlation between catalysts and formation/decomposition of Li₂O₂. Various types of cathode catalysts are discussed to reveal the mechanism of formation/decomposition of Li₂O₂, …

Anodic Electrocatalysis Of Glycerol Oxidation For Hybrid Alkali/Acid Electrolytic Hydrogen Generation, Xin Feng, Bo-Wen Liu, Ke-Xin Guo, Lin-Feng Fan, Gen-Xiang Wang, Su-Qin Ci, Zhen-Hai Wen

Journal of Electrochemistry

Electrolytic hydrogen production is heavily restricted by high-energy consumption majorly due to the relatively high potential of anodic oxygen evolution reaction (OER). Development of OER-alternative reaction at the anode has been recently proposed as a promising pathway to address the associated issues. In this work, we report a hybrid acid/alkali dual-electrolyte electrolyzer by coupling acidic hydrogen evolution reaction (HER) using commercial Pt/C cathode with alkaline Electrocatalytic glycerol oxidation (GOR) which is implemented by developing a nickel foam (NF) supporting Co₃O₄ nanosheets anode that shows low overpotential and high selectivity toward GOR for formate production. The hybrid acid/alkali …

Highly Dispersed Pt Nanoparticles Root In Single-Atom Fe Sites In Ldhs Toward Efficient Methanol Oxidation, Qing-Cheng Meng, Lin-Bo Jin, Meng-Ze Ma, Xue-Qing Gao, Ai-Bing Chen, Dao-Jin Zhou, Xiao-Ming Sun

Journal of Electrochemistry

Active and durable electrocatalysts for methanol oxidation reaction are of critical importance to the commercial viability of direct methanol fuel cell, which has already attracted growing popularities. However, current methanol oxidation electrocatalysts fall far short of expectations and suffer from excessive use of noble metal, mediocre activity, and rapid decay. Here we report the Pt anchored on NiFe-LDHs surface hybrid for stable methanol oxidation in alkaline media. Based on the high intrinsic methanol oxidation activity of Pt nanoparticles, the substrates NiFe-LDHs further enhanced anti-poisoning ability and maintained unaffected stability after 200,000 s cycle test compared to commercial Pt/C catalyst. The …

Preface To Special Issue On Electrocatalysis And Electrosynthesis, Fang-Yi Cheng, Shuang-Yin Wang, Tian-Hua Zhou

Journal of Electrochemistry

No abstract provided.

Hybrid Modeling For Electrochemical Systems, Luis Alejandro Briceno-Mena

LSU Doctoral Dissertations

The discovery of new materials like catalysts, polymeric films, and biomolecules, is driven by industrial needs such as improving reaction or separation selectivity, enhancing therapeutic effects on medical treatments, or reducing costs of replacement. However, deployment of these advances in industrial applications is often hindered by the lack of models needed for design and optimization. Due to the novelty of materials and devices, experimental data and first principles' knowledge are scarce, making it hard to build models either via data-driven or knowledge based approaches. In this context, a way to efficiently combine domain knowledge with data could provide a pathway …

Hemodynamic Investigations In Intracranial Aneurysms: A Commentary, Hang Yi, Mark Johnson, Luke Bramlage, Zifeng Yang, Bryan Ludwig

Mechanical and Materials Engineering Faculty Publications

Intracranial aneurysms (IAs) are abnormal bulges in a blood vessel in the brain that have a potential to rupture and even causing a stroke, which can lead to lasting brain damage, long-term disability, or even loss of life. It has been widely acknowledged that hemodynamic factors, e.g., instantaneous wall shear stress, time-averaged wall shear stress, wall shear stress gradient, gradient oscillatory number, oscillatory shear index, pulsatile blood flow waveform (flow rate magnitude and shape, physical flow period), relative residence time/turnover time, blood pressure, and vortex (i.e., size, location, and numbers), have a close relationship with the pathobiology (i.e., initiation, growth, …

Can Grid-Tied Solar Photovoltaics Lead To Residential Heating Electrification? A Techno-Economic Case Study In The Midwestern U.S., Nelson Sommerfeldt, Joshua M. Pearce

Michigan Tech Publications, Part 1

This study aims to quantify the techno-economic potential of using solar photovoltaics (PV) to support heat pumps (HP) towards the replacement of natural gas heating in a representative North American residence from a house owner's point of view. For this purpose, simulations are performed on: (1) a residential natural gas-based heating system and grid electricity, (2) a residential natural gas-based heating system with PV to serve the electric load, (3) a residential HP system with grid electricity, and (4) a residential HP+PV system. Detailed descriptions are provided along with a comprehensive sensitivity analysis for identifying specific boundary conditions that enable …

Accurate Evaluation Of The Direction-Dependent Mechanical Properties Of Ideal Single Crystals: A Comparative Ab Initio Study, Jaylan Ali Elhalawani

Theses and Dissertations

The mechanical properties of a single crystal or a grain in a polycrystalline material are highly dependent on the direction of the applied load. Key properties of interest are the Young’s modulus and the Poisson ratio in the small strain limit, and the ideal tensile strength in the large strain regime. Prior atomistic computations of these properties interchangeably used two approaches. In one approach the stress-strain response is explicitly calculated via a numerical tensile test experiment. In the second approach the second order single crystal elastic constants are computed via small deformations and then used in analytical equations to derive …

Atomistic Simulation Studies Of Thin Film Growth And Plastic Deformation In Metals And Metal/Ceramic Nanostructures, Reza Namakian

LSU Doctoral Dissertations

Despite the significant improvements in manufacturing and synthesis processes of metals and ceramics in the past decades, there are still areas in which the procedure is still frequently more of an art or skill rather than a science. Therefore, systematic and combined experimental and computational studies are required to facilitate the development of techniques that offer thorough understanding of the events taking place during manufacturing and synthesis processes. With regard to these issues, it is paramount to address microscale characterizations and atomic scale understanding of the events during fabrication processes. One of the focuses of this study is unraveling fundamental …

Impact Of Population Based Indoor Residual Spraying With And Without Mass Drug Administration With Dihydroartemisinin-Piperaquine On Malaria Prevalence In A High Transmission Setting: A Quasi-Experimental Controlled Before-And-After Trial In Northeastern Uganda, Richard C. Elliott

Materials Science and Engineering Faculty Publications and Presentations

Background: Declines in malaria burden in Uganda have slowed. Modelling predicts that indoor residual spraying (IRS) and mass drug administration (MDA), when co-timed, have synergistic impact. This study investigated additional protective impact of population-based MDA on malaria prevalence, if any, when added to IRS, as compared with IRS alone and with standard of care (SOC).

Methods: The 32-month quasi-experimental controlled before-and-after trial enrolled an open cohort of residents (46,765 individuals, 1st enumeration and 52,133, 4th enumeration) of Katakwi District in northeastern Uganda. Consented participants were assigned to three arms based on residential subcounty at study start: MDA+IRS, IRS, SOC. IRS …

Nanoclays‑Containing Bio‑Based Packaging Materials: Properties, Applications, Safety, And Regulatory Issues, Kalpani Y. Perera, Maille Hopkins, Amit K. Jaiswal Dr, Swarna Jaiswal

Articles

Food packaging is an important concept for consumer satisfaction and the increased shelf life of food products. The introduction of novel food packaging materials has become an emerging trend in recent years, which could be mainly due to environmental pollution caused by plastic packaging and to reduce food waste. Recently, numerous studies have been carried out on nanoclays or nanolayered silicate to be used in packaging material development as reinforcing filler composites. Different types of nanoclays have been used as food packaging materials, while montmorillonite (MMT), halloysite, bentonite (BT), Cloisite, and organically modified nanoclays have become of great interest. The …

Laser Powder Bed Fusion Of Molybdenum And Mo-0.1sic Studied By Positron Annihilation Lifetime Spectroscopy And Electron Backscatter Diffraction Method, Nathan E. Ellsworth, Joshua R. Machacek, Ryan A. Kemnitz, Cayla C. Eckley, Brianna M. Sexton, Joel S. Gearhart, Larry W. Burggraf

Faculty Publications

Positron annihilation lifetime spectroscopy (PALS) has been used for the first time to investigate the microstructure of additively manufactured molybdenum. Despite the wide applicability of positron annihilation spectroscopy techniques to the defect analysis of metals, they have only been used sparingly to monitor the microstructural evolution of additively manufactured metals. Molybdenum and molybdenum with a dilute addition (0.1 wt%) of nano-sized silicon carbide, prepared via laser powder bed fusion (LPBF) at four different scan speeds: 100, 200, 400, and 800 mm/s, were studied by PALS and compared with electron backscatter diffraction analysis. The aim of this study was to clarify …