Perturbative Theoretical Model Of Electronic Transient Circular Dichroism Spectroscopy Of Molecular Aggregates,
2022
California State University, Chico
Perturbative Theoretical Model Of Electronic Transient Circular Dichroism Spectroscopy Of Molecular Aggregates, Paul C. Arpin, Daniel B. Turner
Materials Science and Engineering Faculty Publications and Presentations
A chiral analog of transient absorption spectroscopy, transient circular dichroism (TCD) spectroscopy is an emerging time-resolved method. Both spectroscopic methods can probe the electronic transitions of a sample, and TCD is additionally sensitive to the dynamic aspects of chirality, such as those induced by molecular excitons. Here, we develop a theoretical description of TCD for electronic multi-level models in which the pump pulse is linearly polarized and probe pulse is alternately left- and right-circularly polarized. We derive effective response functions analogous to those often used to describe other four-wave mixing methods and then simulate and analyze TCD spectra for three …
Local Structure In High-Entropy Transition Metal Diborides,
2022
Missouri University of Science and Technology
Local Structure In High-Entropy Transition Metal Diborides, Mattia Gaboardi, Frederic Monteverde, Federico Saraga, Giuliana Aquilanti, Lun Feng, William Fahrenholtz, Gregory Hilmas
Materials Science and Engineering Faculty Research & Creative Works
Studies on high-entropy materials often speculate about the effects of lattice distortion and disorder on characteristics such as hardness, thermal expansion, and electronic properties. Notwithstanding the ongoing race to discover new compositions, investigations of the local structure at the atomic level remain sparse at best. Additionally, assessments of the homogeneity of the distribution of metals within the lattice sites are often restricted to techniques such as energy dispersive spectroscopy which might lead to an inaccurate picture of the bulk material. Herein, we report an extensive and systematic study of a class of emerging high-entropy ceramics that uses a combination of …
Tunable Electronic Structure Via Dna-Templated Heteroaggregates Of Two Distinct Cyanine Dyes,
2022
Boise State University
Tunable Electronic Structure Via Dna-Templated Heteroaggregates Of Two Distinct Cyanine Dyes, Jonathan S. Huff, Matthew S. Barclay, Azhad U. Chowdhury, Lance K. Patten, Simon K. Roy, Aaron Sup, Austin Biaggne, Lan Li, Jeunghoon Lee, Paul H. Davis, Bernard Yurke, William B. Knowlton, Daniel B. Turner, Ryan D. Pensack
Materials Science and Engineering Faculty Publications and Presentations
Molecular excitons are useful for applications in light harvesting, organic optoelectronics, and nanoscale computing. Electronic energy transfer (EET) is a process central to the function of devices based on molecular excitons. Achieving EET with a high quantum efficiency is a common obstacle to excitonic devices, often owing to the lack of donor and acceptor molecules that exhibit favorable spectral overlap. EET quantum efficiencies may be substantially improved through the use of heteroaggregates─aggregates of chemically distinct dyes─rather than individual dyes as energy relay units. However, controlling the assembly of heteroaggregates remains a significant challenge. Here, we use DNA Holliday junctions to …
Carbonate-Superstructured Solid Fuel Cells With Hydrocarbon Fuels,
2022
Michigan Technological University
Carbonate-Superstructured Solid Fuel Cells With Hydrocarbon Fuels, Hanrui Su, Wei Zhang, Yun Hang Hu
Michigan Tech Publications
A basic requirement for solid oxide fuel cells (SOFCs) is the sintering of electrolyte into a dense impermeable membrane to prevent the mixing of fuel and oxygen for a sufficiently high open-circuit voltage (OCV). However, herein, we demonstrate a different type of fuel cell, a carbonate-superstructured solid fuel cell (CSSFC), in which in situ generation of superstructured carbonate in the porous samarium-doped ceria layer creates a unique electrolyte with ultrahigh ionic conductivity of 0.17 S.cm21 at 550 °C. The CSSFC achieves unprecedented high OCVs (1.051 V at 500 °C and 1.041 V at 550 °C) with methane fuel. Furthermore, the …
Impulse, Fall 2022,
2022
South Dakota State University
Impulse, Fall 2022, University Marketing And Communications, Jerome J. Lohr College Of Engineering
Impulse (Jerome J. Lohr College of Engineering Publication)
2 | Sanjeev Kumar Takes Helm as College’s 12th Dean
5 | College Develops Partnerships in India, Turkey
6 | Faculty News
8 | Aerofly — Profs, Alum Partner To Build Unique Drone
10 | Researchers Find Way to Extend Produce Shelf Life
12 | SDSU Claims National Title in Quarter-Scale Tractors
14 | Nation’s Top ASCE Chapter Housed at SDSU
16 | National Geo-Video Title Won By State Students
18 | Summer Brings Engineering Camps to Campus
20 | Haleigh Timmer — Money on the Court, In Classroom
22 | Daniel Burkhalter — Day in the Life of Student-Athlete …
Stochastic Model For High Temperature Oxidation Of Cr–Ni Austenitic Steels Assisted By Spallation,
2022
Missouri University of Science and Technology
Stochastic Model For High Temperature Oxidation Of Cr–Ni Austenitic Steels Assisted By Spallation, Simon N. Lekakh, Oleg Neroslavsky, Mei Li, Larry Godlevski
Materials Science and Engineering Faculty Research & Creative Works
Cr–Ni austenitic steels offer significant high temperature corrosion protection by forming a surface oxide layer. However, above critical service conditions (temperature, atmosphere, thermal cycling), oxidized surface can experience intensive degradation because of scale spallation, which could be detrimental to the in-service life. To predict the effect of scale spallation on oxidation kinetics, a simulation was implemented using a stochastic model. The model considers topological parameters and intensity of spallation which can occur, while delivering a true oxidation constant. The experimental procedure identified the amount of formed spalled scale and topology of spallation based on the use of element mapping of …
Effect Of Cu Additions On Scale Structure And Descaling Efficiency Of Low C Steel Reheated In A Combustion Gas Atmosphere,
2022
Missouri University of Science and Technology
Effect Of Cu Additions On Scale Structure And Descaling Efficiency Of Low C Steel Reheated In A Combustion Gas Atmosphere, Richard Osei, Simon Lekakh, Ronald J. O'Malley
Materials Science and Engineering Faculty Research & Creative Works
Modern EAF steelmaking employs scrap as its primary source of raw material. Different sources of scrap have varying levels of residuals, which can negatively influence product properties, performance, and surface quality. The presence of some residuals, such as Cu and Ni in controlled quantities, can also positively impact steel performance for some applications. It is also well known that interactions between residuals and alloying elements in steel can modify the structure of scale formed during slab reheating prior to hot rolling. These changes in the scale structure can influence scale removability. In this study, the effect of varying Cu concentrations …
Fusion Welding Of Refractory Metals And Zrb2-Sic-Zrc Ceramics,
2022
Missouri University of Science and Technology
Fusion Welding Of Refractory Metals And Zrb2-Sic-Zrc Ceramics, Jecee D. Jarman, William Fahrenholtz, Greg Hilmas, Jeremy Lee Watts, Tieshu Huang
Materials Science and Engineering Faculty Research & Creative Works
Molybdenum and a molybdenum alloy were fusion welded to ZrB2-based ceramics to determine if the electrical and thermal properties of the metals and ceramics affected their weldability. Commercial ceramic powders were hot pressed, machined into coupons, and preheated to 1600 °C before joining the ceramics to commercial metals using plasma arc welding. Weldability varied as indicated by the range of porosity observed within the fusion zones. Measured thermal and electrical properties appeared to have little to no effect on the weldability of metal-ceramic welds despite the large range of values measured across each property. Differences in melting temperatures between metal …
Oxygen Vacancies In Lib3O5 Crystals And Their Role In Nonlinear Absorption,
2022
Air Force Institute of Technology
Oxygen Vacancies In Lib3O5 Crystals And Their Role In Nonlinear Absorption, Brian C. Holloway, Christopher A. Lenyk, Timothy D. Gustafson, Nancy C. Giles
Faculty Publications
LiB3O5 (LBO) crystals are used to generate the second, third, and fourth harmonics of near-infrared solid-state lasers. At high power levels, the material’s performance is adversely affected by nonlinear absorption. We show that as-grown crystals contain oxygen and lithium vacancies. Transient absorption bands are formed when these intrinsic defects serve as traps for “free” electrons and holes created by x rays or by three- and four-photon absorption processes. Trapped electrons introduce a band near 300 nm and trapped holes produce bands in the 500-600 nm region. Electron paramagnetic resonance (EPR) is used to identify and characterize the …
Zinc–Acetate–Amine Complexes As Precursors To Zno And The Effect Of The Amine On Nanoparticle Morphology, Size, And Photocatalytic Activity,
2022
Boise State University
Zinc–Acetate–Amine Complexes As Precursors To Zno And The Effect Of The Amine On Nanoparticle Morphology, Size, And Photocatalytic Activity, Josh Eixenberger, David Estrada
Materials Science and Engineering Faculty Publications and Presentations
Zinc oxide is an environmentally friendly and readily synthesized semiconductor with many industrial applications. ZnO powders were prepared by alkali precipitation using different [Zn(acetate)2(amine)x] compounds to alter the particle size and aspect ratio. Slow precipitations from 95 °C solutions produced micron-scale particles with morphologies of hexagonal plates, rods, and needles, depending on the precursor used. Powders prepared at 65 °C with rapid precipitation yielded particles with minimal morphology differences, but particle size was dependent on the precursor used. The smallest particles were produced using precursors that yielded crystals with low aspect ratios during high-temperature synthesis. Particles …
Additive Manufacturing Of Complexly Shaped Sic With High Density Via Extrusion-Based Technique – Effects Of Slurry Thixotropic Behavior And 3d Printing Parameters,
2022
Missouri University of Science and Technology
Additive Manufacturing Of Complexly Shaped Sic With High Density Via Extrusion-Based Technique – Effects Of Slurry Thixotropic Behavior And 3d Printing Parameters, Ruoyu Chen, Adam Bratten, Joshua Rittenhouse, Tian Huang, Wenbao Jia, Ming-Chuan Leu, Haiming Wen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Additive manufacturing of dense SiC parts was achieved via an extrusion-based process followed by electrical-field assisted pressure-less sintering. The aim of this research was to study the effect of the rheological behavior of SiC slurry on the printing process and quality, as well as the influence of 3D printing parameters on the dimensions of the extruded filament, which are directly related to the printing precision and quality. Different solid contents and dispersant- Darvan 821A concentrations were studied to optimize the viscosity, thixotropy and sedimentation rate of the slurry. The optimal slurry was composed of 77.5 wt% SiC, Y2O3 and Al2O3 …
Investigation Of Adhesion, Deformation Mechanics, And Electrical Properties Of Ag/Sio2/Pdms Tri-Layers For Stretchable Electronic Applications,
2022
Rowan University
Investigation Of Adhesion, Deformation Mechanics, And Electrical Properties Of Ag/Sio2/Pdms Tri-Layers For Stretchable Electronic Applications, Rhandy Joe Paladines
Theses and Dissertations
The motivation behind this research is to improve the interfacial layer bonding of metallic thin films to PDMS substrates with the aid of a buffer layer. The physical vapor deposition (PVD) technique of sputtering was used to deposit bilayer thin films of silver (Ag) and silicon dioxide (SiO2) on PDMS. Two chamber pressures were used in this work, 5 and 20 mTorr, to investigate the role of this parameter in determining the interfacial adhesion and the role in determining the resistance sensitivity. Studies of the surface energy and increased bonding strength for metallization are carried out. Surface characterization using atomic …
Towards Environmentally Sustainable, High-Performance, Lightweight Composites For Automotive Applications,
2022
Rowan University
Towards Environmentally Sustainable, High-Performance, Lightweight Composites For Automotive Applications, Jasmin Zamudio Vasquez
Theses and Dissertations
The increasing public demand in the world automotive industry to improve the environmental sustainability of their manufactured vehicles without sacrificing drivers' comfort and safety and the high cost of lightweight materials have driven researchers to reconsider materials used in the automotive application. Thus, this work aims toward the production of environmentally sustainable, high-performance, lightweight composites, utilizing recycled carbon fibers (RCFs) and pyrolyzed tire particles (PTPs) reclaimed from pyro-gasification of CFRP wastes and end-of-life tires (ELTs), respectively, as reinforcements for cardanol-based epoxy resins. The fabricated composites exhibited rubbery-like behavior at 25 °C. Spectroscopic, rheological, physical, thermal, thermomechanical, and mechanical characterizations were …
Development Of High-Performance Fiber Cement: A Case Study In The Integration Of Circular Economy In Product Design,
2022
Kasetsart University
Development Of High-Performance Fiber Cement: A Case Study In The Integration Of Circular Economy In Product Design, Parinya Chakartnarodom, Sarunya Wanpen, Wichit Prakaypan, Edward A. Laitila, Nuntaporn Kongkajun
Michigan Tech Publications
A new fiber cement (FC) is designed with the integration of circular economy (CE) concepts, in particular a product that is recyclable yet maintains performance. The FC samples were prepared from the mixtures of ordinary Portland cement (OPC), sand, and cellulose fibers, and required an inclusion compound (IC) and water. From the heat of hydration tests, the most effective IC, IC1, was prepared from lithium silicate, sodium thiocyanate, alkylbenzene sulfonate, and hydrochloric acid. The FC samples were recycled by crushing and grinding, then used as sand replacement in varying amounts to produce new FC samples. The results from the mechanical …
Bio-Based Food Packaging Material For Intelligent Food Packaging Applications For Chicken Fillets,
2022
Technological University Dublin
Bio-Based Food Packaging Material For Intelligent Food Packaging Applications For Chicken Fillets, Kalpani Y. Perera, Amit K. Jaiswal, Swarma Jaiswal, Shubham Sharma
Articles
Bionanocomposite packaging is made up of bio- based materials that have high performance activity and are ecologically sustainable alternatives to packaging made of synthetic polymers. Intelligent packaging retains track of the state of the food and the environment in which it is stored, and communicates relevant changes to the consumer through visualization or other methods. The aim of this study was to develop a bionanocomposite intelligent packaging material by utilising sodium alginate, gelatin, nanoclay and curcumin. Sodium alginate, gelatin film incorporated with Curcumin (Cur), and Nanoclay (NC) in various concentrations (0% W/V, 0.5% W/V, 1% W/V and 1. 5% W/V) …
Thermal Post-Processing Of 3d Printed Polypropylene Parts For Vacuum Systems,
2022
Michigan Technological University
Thermal Post-Processing Of 3d Printed Polypropylene Parts For Vacuum Systems, Pierce Mayville, Aliaksei L. Petsiuk, Joshua M. Pearce
Michigan Tech Publications
Access to vacuum systems is limited because of economic costs. A rapidly growing approach to reduce the costs of scientific equipment is to combine open-source hardware methods with digital distributed manufacturing with 3D printers. Although high-end 3D printers can manufacture vacuum components, again, the cost of access to tooling is economically prohibitive. Low-cost material extrusion 3D printing with plastic overcomes the cost issue, but two problems arise when attempting to use plastic in or as part of vacuum systems: the outgassing of polymers and their sealing. To overcome these challenges, this study explores the potential of using post-processing heat treatments …
Developing Positive Thermal Coefficient (Ptc) Heaters For Solar Electric Cooking,
2022
California Polytechnic State University, San Luis Obispo
Developing Positive Thermal Coefficient (Ptc) Heaters For Solar Electric Cooking, Katarina Ivana Brekalo, Andrew Shepherd
Physics
Positive Thermal Coefficients, PTCs, are materials that abruptly change in resistance in response to changes in temperature. The purpose of this experiment is to explore the viability of using the switching type ceramic PTC thermistor as a replacement for current resistive heaters. These types of PTCs have a nonlinear change in resistance with increases in temperature. This device will be used as a temperature-controlling heating element intended to power an Insulated Solar Electric Cooker (ISEC). The ISEC is designed to cook meals throughout the day for impacted communities as an alternative cooking method that doesn’t require biofuel as an energy …
Influence Of Defects On In-Plane Dynamic Properties Of Hexagonal Ligament Chiral Structures,
2022
Old Dominion University
Influence Of Defects On In-Plane Dynamic Properties Of Hexagonal Ligament Chiral Structures, Ning An, Xunwen Su, Dongmei Zhu, Mileta M. Tomovic
Engineering Technology Faculty Publications
Although the six-ligament chiral structure has many unique properties, due to its special structure, the stress concentration is prone to defects. In addition, additive manufacturing is also prone to defects. This paper studies the effect of defects, which is helpful for the better application of the six-ligament chiral structure. Several new six-ligament chiral structures with random and concentrated defects were designed to explore the effects of the defects on the in-plane dynamic properties. The structures were studied with the finite element ANSYS/LSDYNA numerical simulation and experimental methods. According to the defect-free six-ligament chiral structures exhibiting different deformation modes at different …
Processing And Mechanical Properties Of Hot-Pressed Zirconium Diboride – Zirconium Carbide Ceramics,
2022
Missouri University of Science and Technology
Processing And Mechanical Properties Of Hot-Pressed Zirconium Diboride – Zirconium Carbide Ceramics, Eric W. Neuman, William Fahrenholtz, Gregory E. Hilmas
Materials Science and Engineering Faculty Research & Creative Works
ZrB2 was mixed with 0.5 wt% carbon and up to 10 vol% ZrC and densified by hot-pressing at 2000 °C. All compositions were > 99.8% dense following hot-pressing. The dense ceramics contained 1–1.5 vol% less ZrC than the nominal ZrC addition and had between 0.5 and 1 vol% residual carbon. Grain sizes for the ZrB2 phase decreased from 10.1 µm for 2.5 vol% ZrC to 4.2 µm for 10 vol% ZrC, while the ZrC cluster size increased from 1.3 µm to 2.2 µm over the same composition range. Elastic modulus was ~505 GPa and toughness was ~2.6 MPa·m½ for all compositions. …
Mechanical Activation And Cation Site Disorder In Mgal2o4,
2022
Missouri University of Science and Technology
Mechanical Activation And Cation Site Disorder In Mgal2o4, Cole A. Corlett, Matthias D. Frontzek, Nina Obradovic, Jeremy Lee Watts, William Fahrenholtz
Materials Science and Engineering Faculty Research & Creative Works
The synthesis and crystallographic site occupancy were investigated for MgAl2O4 with and without mechanical activation of the precursor powders. Heating to 1200 °C or higher resulted in the formation of a single spinel phase regardless of whether the powders were mechanically activated or not. Neutron diffraction analysis was used to determine cation site occupancy and revealed that mechanical activation resulted in a lower degree of cation site inversion compared to the nonactivated materials, which indicated that the powders were closer to thermodynamic equilibrium. This is the first study to characterize the effects of mechanical activation on crystallographic site occupancy in …
