Materials Science and Engineering Commons^™

Investigating Near-Field Radiative Heat Transfer With Titanium Carbide Mxenes And Slanted Columnar Thin Films, Sean Luke Murray

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This work investigates the mechanisms to manipulate and control the magnitudes of Near-Field Radiative Heat Transfer (NFRHT) using two-dimensional materials and nanostructured surfaces. NFRHT occurs when the geometrical features of the radiating objects or the separation distance between interacting bodies are comparable to or lower than the characteristic thermal radiation wavelength. NFRHT magnitudes surpass the blackbody limit by several orders of magnitude due to phenomena such as photon tunneling and new modes of energy transfer, like surface polaritons. Therefore, it is crucial to understand how material properties and surface nanostructures affect NFRHT.

The first part of this work examines the …

Computational Alchemy: Pioneering Spintronic, Thermoelectric, And Optoelectronic Materials Design Through First-Principles Calculations And Machine Learning, Eesha Sanjay Andharia

Graduate Theses and Dissertations

Intelligent materials discovery and design plays a pivotal role in advancement of spintronics, optoelectronics and thermoelectric devices and technology. In this study, we investigate three types of materials using first principles calculations. First, the structural, electronic, and magnetic properties of CrTiCoZ (Z = Al, Si) equiatomic quaternary Heusler alloys were investigated. CrTiCoAl compound was found to exhibit a half metallic ferromagnetic structure and Curie temperature above room temperature, which makes it an ideal candidate for magnetic tunnel junction, the basic building block of Spintronic devices. Second, we use Green’s function to obtain the finite temperature phonons by including quartic anharmonicity …

Fabrication And Characterization Of Lignin–Pva Hydrogels With Tunable Network Structures, Keturah Bethel

All Dissertations

The ability to directly tune the crosslinked network structure of hydrogels is crucial for their functional applications in various fields, such as water filtration, protein separation, and tissue engineering. By controlling the crosslink density of the hydrogel, one can directly alter the mesh size – i.e., the end-to-end distance between crosslink junctions – and, subsequently, directly alter the hydrogel performance. This work discusses the fabrication and characterization of soft composites containing the biopolymer, lignin, are discussed. Precisely, physically-crosslinked composite lignin–Poly(vinyl alcohol) (PVA) hydrogels were fabricated via the freeze-thaw (F/T) pathway, whereby solutions containing specified amounts of PVA and lignin were …

Modeling Study Of Si3N4 Waveguides On A Sapphire Platform For Photonic Integration Applications, Diandian Zhang, Shui-Qing Yu, Gregory J. Salamo, Richard A. Soref, Wei Du

Electrical Engineering and Computer Science Faculty Publications and Presentations

Sapphire has various applications in photonics due to its broadband transparency, high-contrast index, and chemical and physical stability. Photonics integration on the sapphire platform has been proposed, along with potentially high-performance lasers made of group III–V materials. In parallel with developing active devices for photonics integration applications, in this work, silicon nitride optical waveguides on a sapphire substrate were analyzed using the commercial software Comsol Multiphysics in a spectral window of 800~2400 nm, covering the operating wavelengths of III–V lasers, which could be monolithically or hybridly integrated on the same substrate. A high confinement factor of ~90% near the single-mode …

Enhancing Thermal Stability Of Perovskite Solar Cells Through Thermal Transition And Thin Film Crystallization Engineering Of Polymeric Hole Transport Layers, Sanggyun Kim, Sina Sabury, Carlo A. R. Perini, Tareq Hossain, Augustine O. Yusuf, Xiangyu Xiao, Ruipeng Li, Kenneth R. Graham, John R. Reynolds, Juan-Pablo Correa-Baena

Chemical and Materials Engineering Faculty Publications

Organic hole transport layers (HTLs) have been known to be susceptible to thermal stress, leading to poor long- term stability in perovskite solar cells (PSCs). We synthesized three 2,5-dialkoxy-substituted, 1,4-bis(2-thienyl)phenylene (TPT)-based conjugated polymers (CPs) linked with thiophene-based (thiophene (T) and thienothiophene (TT)) comonomers and evaluated them as HTLs in n-i-p PSCs. TPT-T (MB/C6), which has branched 2- methylbutyl and linear hexyl (MB/C6) side chains, emerged as a promising HTL candidate, enabling power conversion efficiencies (PCEs) greater than 15%. In addition, PSCs with this HTL showed an improvement in long-term stability at elevated temperatures of 65 °C when compared to those …

Synthesis Of Selenium Nanostructures: Rods, Wires, And Fibers By Pulsed Laser Ablation In Liquids, Atikur Rahman

Theses and Dissertations

Selenium is a semiconductor that has a bulk energy bandgap of 1.74 eV, is mainly used in sensors, rectifiers, and advanced photovoltaic solar cells. Selenium is very important for the energy applications and was declared as Energy Critical Element (ECE) by the American Physical Society (APS) and the Materials Research Society (MRS). The goal of this dissertation was to control the growth of selenium when being irradiated by a pulsed laser within a liquid environment. The method called “Pulsed Laser Ablation in Liquids” is a green synthesis technique that allows for ligand-free nanoparticles to be created. Laser repetition rates were …

Laser Surface Processing For Enhanced Adhesion Between Diamond Coatings And Metallic Substrates, Zhipeng Wu

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Application of diamond coatings on metallic substrates endows them with superior properties including mechanical robustness and corrosion resistance, rendering them highly adaptable for diverse industrial and technological applications. However, significant disparities in coefficients of thermal expansion (CTEs) result in pronounced residual stress near interfaces, causing delamination of the diamond coatings. Moreover, weak chemical bonding poses a concern for certain metallic substrates. Laser surface processing techniques show promise in enhancing adhesion by altering stress distribution and improving mechanical bonding. Therefore, the research efforts described in this dissertation mainly focus on femtosecond (fs) laser texturing for enhanced adhesion of diamond coatings on …

Molecular Beam Epitaxy Of Gesn On Iii-V Substrates For Photonic Applications, Calbi Gunder

Graduate Theses and Dissertations

This dissertation explores the advancement of germanium-tin (GeSn) as a tuneable narrow bandgap material, crucial for the development of high-efficiency photodetectors and laser devices in near- and mid-infrared technologies. We investigate the synthesis challenges, particularly the lattice mismatch between GeSn alloys and substrates, which significantly affects their crystalline and optical qualities. Through molecular beam epitaxy, we examine the growth of Ge and GeSn on GaAs (001) substrates, employing Ge/GaAs and Ge/AlAs buffer layers to investigate these challenges. Our findings, characterized by X-ray diffraction, atomic force microscopy, reflection high-energy electron diffraction, and photoluminescence, demonstrate the production of high-quality Ge layers, achieving …

Resolving The Size And Charge Of Small Particles: A Predictive Model Of Nanopore Mechanics, Samuel Bearden, Tigran M. Abramyan, Dmitry Gil, Jessica Johnson, Anton Murashko, Sergei Makaev, David Mai, Alexander Baranchikov, Vladimir Ivanov, Vladimir Reukov, Guigen Zhang

Chemical and Materials Engineering Faculty Publications

The movement of small particles and molecules through nanopore membranes is widespread and has far-reaching implications. Consequently, the development of mathematical models is essential for understanding these processes on a micro level, leading to deeper insights. In this endeavor, we suggested a model based on a set of empirical equations to predict the transport of substances through a solid-state nanopore and the associated signals generated during their translocation. This model establishes analytical relationships between the ionic current and electrical double-layer potential observed during analyte translocation and their size, charge, and mobility in an electrolyte solution. This framework allows for rapid …

Performance And Enhanced Efficiency Induced By Cold Plasma On Sapo-34 Membranes For Co2 And Ch4 Mixtures, Fnu Gorky, Vashanti Storr, Grace Jones, Apolo Nambo, Jacek B. Jasinski, Maria L. Carreon

Chemical Engineering Faculty Publications and Presentations

In this study, we investigate the influence of cold-plasma-induced enhanced performance and efficiency of SAPO-34 membranes in the separation of CO₂ and CH₄ mixtures. Placing the herein presented research in a broader context, we aim to address the question of whether cold plasma can significantly impact the membrane performance. We subjected SAPO-34 membranes to plasma mild disturbances and analyzed their performance in separating CO₂ and CH₄. Our findings reveal a notable enhancement in membrane efficiency and sustained performance when exposed to cold plasma. The pulsed plasma separation displayed improved structural integrity, and the experimental results …

Understanding And Tuning Magnetism In Van Der Waals-Type Metal Thiophosphates, Rabindra Basnet, Jin Hu

Physics Faculty Publications and Presentations

Over the past two decades, significant progress in two-dimensional (2D) materials has invigorated research in condensed matter and material physics in low dimensions. While traditionally studied in three-dimensional systems, magnetism has now been extended to the 2D realm. Recent breakthroughs in 2D magnetism have attracted substantial interest from the scientific community, owing to the stable magnetic order achievable in atomically thin layers of the van der Waals (vdW)-type layered magnetic materials. These advances offer an exciting platform for investigating related phenomena in low dimensions and hold promise for spintronic applications. Consequently, vdW magnetic materials with tunable magnetism have attracted significant …

In Situ Shear Exfoliation Of Layered Materials And Fabrication Of Multifunctional Composites, Md Abdur Rahman Bin Abdus Salam

Theses and Dissertations

To harness the extraordinary properties of 2D nanomaterials across a range of applications, including but not limited to device fabrication (such as sensors and transistors), energy storage and conversion systems (like batteries and solar cells), as well as biomedical applications (such as drug delivery and tissue engineering), it is imperative to achieve proper synthesis to single-layer form from bulk material, ensuring defect-free synthesis. Recognizing the criticality of defect-free synthesis and high yield for nanocomposite production, our focus centered on developing a facile, contamination-free, single-step, in situ shear exfoliation process for bulk materials (such as graphene, hBN, coal) within elastomers, which …

Attachment Of 2d Nanomaterials Onto 1d Nanofibers For Separation And Sensing Applications, Elmmer A. Vera Alvarado

Theses and Dissertations

Advancing materials for water desalination and sensing is essential for tackling global issues related to clean water and efficient energy systems. This thesis explores the application of 2D nanomaterials, specifically graphene, integrated onto 1D poly(vinylidene fluoride) (PVDF) nanofibers to enhance their effectiveness in these areas. Utilizing innovative techniques such as Forcespinning® and plasma treatment, PVDF nanofibers were strengthened with graphene and conductive polymers like poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT: PSS). The research involved thorough assessments using direct contact membrane distillation (DCMD) systems, oil-water separation tests, and various mechanical and electromechanical evaluations. Heat-pressed membranes consistently delivered a flux of 0.33 kg/m²/hr and …

Understanding The Microstructure And Tribological Performance Of Cocrfeni-Based High Entropy Alloys, Ali Azarmi

All Theses

Due to their higher wear resistance compared to conventional alloys, high entropy alloys (HEAs) are now being considered as candidates for parts undergoing sliding contact during their lifetimes. While the engineering field has built some knowledge related to the performance of selected high entropy alloys, such as the CoCrFeNi alloy, more research is needed to determine if (how) expansions from four to five principal alloying elements alter the performance compared to the initial alloy. In this study, we started this research effort by investigating the relative performance of CoCrFeNiMn and CoCrFeNiTi with respect to CoCrFeNi. The two primary alloying elements …

Local Charge Distortion Due To Cr In Ni-Based Concentrated Alloys, Jacob Fischer

All Theses

Due to the presence of multiple elements consisting of a range of atomic radii, local lattice distortion (LLD) is commonly observed in concentrated (and high entropy) alloys. However, since these elements also have diverse electronegativities, recent works show that atoms can have a range of atomic charges. In this work, using density functional theory (DFT), we investigate electronic charge distribution in face centered cubic (FCC) Ni-based alloys and find significant charge-density distortion in HEAs. Specifically, Cr atoms have large charge density distortion that results in a wide range of bond lengths, atomic charges, and electronic density of states in Cr-containing …

Predicting The Ductility Of Tungsten Based Bcc Refractory High Entropy Alloys: A Computational Science Driven Study, Akshay Korpe

All Theses

Bcc refractory high entropy alloys (HEAs) are a relatively new category of metallic alloys that promise excellent irradiation resistance and strength retention at high temperatures but exhibit brittle behavior at room temperatures limiting their formability. Understanding the deformation mechanisms and predicting their ductility at room temperature is a topic of interest in contemporary research.

In this work, multiple independent ductility criteria for quantifying the ductility of these HEAs were studied, calculated and compared using Density Functional Theory (DFT) calculations and continuum mechanics frameworks. These ductility parameters were calculated for various W-Ta-Cr-V alloys and the trends were analyzed for each criteria …

Proportioning And Performance Of Ultra-High Performance Concrete (Uhpc) For High Friction Surface Treatment (Hfst) On Pavement And Bridge Decks, Adam R. Biehl

All Theses

High Friction Surface Treatment (HFST) is a roadway remediation technique used to improve pavement’s coefficient of friction, to enhance roadway safety. The application of HFSTs has repeatedly demonstrated the ability to significantly reduce crashes in both wet and dry conditions. Typically, epoxy-resins and calcined bauxite aggregate are used in HFST treatment. However, the high material costs and scarcity of calcined bauxite render this form of HFST an expensive and limited option for roadway rehabilitation. Therefore, the identification of alternative binders and HFST aggregates is needed for broad scale implementation. One potential alternative binder is Ultra-High-Performance Concrete (UHPC), a specialty cementitious …

Development Of Recyclable Materials For Industry Using Non-Petroleum Feedstocks, Terra M. Miller-Cassman

Boise State University Theses and Dissertations

Plastics have been an essential material for over 80 years, yet we have been unable to manage the accumulation of plastic waste. The available solutions for recycling or replacing plastics are complex and costly, and thus have not kept pace with the increasing quantity of plastic waste. This dissertation describes a comprehensive, materials design approach to solving the current and future challenges of plastic waste. Recycled and recyclable materials are developed using commercial feedstocks to reduce barriers for industry adoption. In one approach, unsorted municipal solid waste is compressed at a low temperature and pressure to form rigid composite boards …

Development And Processing Of Shape Memory Polymer Composites (Smpcs) For Application In Structural Robotics And Robotic Sensors., Kavish Sudan

Electronic Theses and Dissertations

Shape Memory Polymers (SMPs) have attracted significant attention since their introduction in the 1980s due to their remarkable ability to regain their original shape from a temporarily deformed state when exposed to an external stimulus, typically heat. This shape memory effect, driven by thermal transitions such as the glass transition temperature (T_g) or melting temperature (T_m), has made SMPs highly attractive for applications in soft robotics, aerospace, and biomedical devices. However, SMPs face challenges such as limited mechanical strength, thermal stability, and electrical conductivity, which hinder their broader adoption in advanced applications. To address these challenges, …

Synergistic Strategies In Hybrid Mxed Matrix 3d Printing Of Thermoplastics & Thermosets: Design, Manufacturing, And Materials Development., Saleh Akram Khanjar

Electronic Theses and Dissertations

Composite manufacturing and mixed matrix structures have been produced using traditional manufacturing processes for various industrial applications due to their high mechanical properties to material weight and cost ratio. However implementation of composite and mixed matrix manufacturing with advanced manufacturing such as additive manufacturing is limited due to the hardware limitations of current 3d printing technologies and materials available for 3D printing applications. This work has developed and investigated a new hybrid 3D printing manufacturing process utilizing a variety of material systems (thermoplastic – thermoset, thermoplastic – thermoplastic, thermoset – thermoset, thermoplastic – thermoplastic – thermoset). This study developed thermoplastic …

Fracture Behavior Of Advanced Technology Fuels For Light Water Reactors, Adrianna Elizabeth Lupercio

Boise State University Theses and Dissertations

The urgent call to decarbonize our energy infrastructure, while simultaneously meeting growing energy demands, highlights the need for reliable and clean energy sources. Nuclear energy provides reliable, high-capacity baseload electricity while emitting zero greenhouse gases during operation. To adequately meet the energy needs of society and maintain economic viability, it is crucial to enhance the efficiency of nuclear power plant (NPP) operations. Upgrades to NPP operations require near-term Advanced technology Fuel (ATF), such as doped UO₂, to increase the flexibility of plant operation without impacting safety margins.

Small additions of metal oxide dopants are reported to increase grain …

Physics-Informed Machine Learning Methods For Inverse Design Of Multi-Phase Materials With Targeted Mechanical Properties, Yunpeng Wu

All Dissertations

Advances in machine learning algorithms and applications have significantly enhanced engineering inverse design capabilities. This work focuses on the machine learning-based inverse design of material microstructures with targeted linear and nonlinear mechanical properties. It involves developing and applying predictive and generative physics-informed neural networks for both 2D and 3D multiphase materials.

The first investigation aims to develop a machine learning method for the inverse design of 2D multiphase materials, particularly porous materials. We first develop machine learning methods to understand the implicit relationship between a material's microstructure and its mechanical behavior. Specifically, we use ResNet-based models to predict the elastic …

On The Structure, Energy, And Segregation Behavior Of Grain Boundaries In Metallic Systems, Yasir Mahmood

All Dissertations

Nearly all structural metallic systems are multi-component polycrystalline aggregates; their microstructures are composed of crystalline grains that are internally joined at grain boundaries (GBs). This thesis focuses on GB structure, energy, and chemistry, as these greatly influence many material properties and processes, including boundary dynamics during processing treatments or under operating conditions.

Using atomistic simulations, we examine the impact of metastable GB structures on solute segregation. A wide range of GB geometries and metastable structures are used in our study. The Al-Mg alloy is used because it is of interest for light weighting. The atomistic simulation results are used to …

Exploring The Synthesis Of Biobased And Chemically Recyclable Polysulfone Using Imine Chemistry, Vitasta Jain

All Dissertations

Plastic waste poses a major problem because of the chemical stability of these materials, leading to their accumulation in the environment and the leaching of toxic chemicals during their slow decomposition. Additionally, the use of depleting petroleum reserves for synthesis has made for an unsustainable production and risks due to use of chemicals hazardous to the environment and the individuals exposed to it.

To address these concerns, researchers have explored biobased feedstock and incorporating chemical recycling capabilities for a closed loop, sustainable process. One promising feedstock is lignin with its abundant functional groups that can be modified and utilized to …

Development Of Iii-V And Iv Epitaxy On Sapphire Technology, Emmanuel Wangila

Graduate Theses and Dissertations

This research presents comprehensive insights into the epitaxial growth of germanium (Ge) on c-plane sapphire substrates using molecular beam epitaxy (MBE). The direct growth of Ge on sapphire typically yields three-dimensional (3D) Ge islands with diverse growth directions, multiple primary domains, and twinned crystals. However, incorporating a thin AlAs nucleation layer proves instrumental in enhancing surface and material quality. With a 10 nm AlAs layer, the achieved surface exhibits improved characteristics, including a smoother surface, single epitaxial orientation, sharper rocking curve, and a single domain. This study surpasses previous works by achieving a single primary domain and reducing twinning. Furthermore, …

High-Quality Single-Step Growth Of Gaas On C-Plane Sapphire By Molecular Beam, Emmanuel Wangila, Calbi Gunder, Mohammad Zamani-Alavijeh, Fernando Maia De Oliveira, Serhii Kryvyi, Aida Sheibani, Yuriy I. Mazur, Shui-Qing Yu, Gregory J. Salamo

Physics Faculty Publications and Presentations

We report on the growth of high-quality GaAs semiconductor materials on an AlAs/sapphire substrate by molecular beam epitaxy. The growth of GaAs on sapphire centers on a new single-step growth technique that produces higher-quality material than a previously reported multi-step growth method. Omega-2theta scans confirmed the GaAs (111) orientation. Samples grown at 700 °C displayed the highest crystal quality with minimal defects and strain, evidenced by narrow FWHM values of the rocking curve. By varying the As/Ga flux ratio and the growth temperature, we significantly improved the quality of the GaAs layer on sapphire, as compared to that obtained in …

Synthesis Of Silica-Encapsulated Myristic Acid Phase-Change-Assisted Nanocapsules For Thermal Management Applications, Muhammad Ghufran, David Huitink

Mechanical Engineering Faculty Publications and Presentations

Myristic acid-based silica (MA/SiO₂) nano-encapsulated phase change materials (NePCMs) were synthesized by the sol–gel process. Five different samples of the MA/SiO₂ nanocapsules were prepared by varying the mass of the myristic acid. The nanocapsules were characterized by Fourier transform infrared spectrophotometer (FTIR), X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX), and dynamic light scattering (DLS). These characterization techniques confirmed the successful encapsulation of the myristic acid inside the silica shell. The maximum latent heat was found to be 114.46 J/g for the sample which was prepared with 25 g myristic …

Smart Automatic Modal Hammer Predictor–Corrector Approach For Accurate Excitation Of Dynamical Systems, Mohammad Nasr

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This research introduces an innovative solution that revolutionizes the study of linear and nonlinear dynamical systems—a smart automatic modal hammer. With its affordability and intelligent capabilities, this automatic modal hammer becomes an invaluable tool for research and industry, enabling repeatable strikes with precise force control. This system's significance becomes particularly evident when studying nonlinear systems, which heavily rely on the excitation level for their dynamics. By offering a cost-effective design this proposed system proves to be robust in accelerating research on nonlinear dynamics, providing researchers with an efficient and accessible means to delve deeper into these complex systems. The proposed …

Ultrasonic Nondestructive Quantification Of Case Depth In Railroad Bearing Components, Trevor K. Adelung

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

While in service, railroad bearings must withstand large loads to ensure smooth operation. These large loads can lead to failure due to rolling contact fatigue (RCF), for which small cracks initiate just beneath the surface of the components. As a preventative measure, bearings are manufactured with a hardened surface layer called the effective case depth (ECD). Current methods in industry use destructive hardness testing to quantify the ECD. While accurate, this method is costly and time consuming. Ultrasonic nondestructive testing would provide a more efficient and cost-effective method to determine ECD. In this thesis, diffuse ultrasonic shear backscatter was used …

Studies Of Exotic Electronic, Optical, And Electrochemical Properties In Nanoparticle Assembly And Graphene, Jay Min Lim

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

It is well known that exotic properties and phenomena emerge as structural dimensions shrink to nanoscales. We self-assembled one-dimensional chains of gold nanoparticles in solution and quantified the growth process by monitoring the redshift of localized surface plasmon resonance (LSPR). Curiously, the redshift stopped while the chains continued to rearrange as manifested by gradual reduction in the LSPR peak. Using electromagnetic simulations, we quantitatively explained the phenomena as a rapid “addition-polymerization” followed by a sharp transition to “condensation-process.” Next, recognizing the significant electric field enhancement in the interparticle gap, a photoluminescent-active Eu³⁺ ion was used to probe Surface-Enhanced Photoluminescence …