Materials Science and Engineering Commons^™

Activated Carbon Preparation And Modification For Adsorption, Yuhe Cao

Electronic Theses and Dissertations

Butanol is considered a promising, infrastructure-compatible biofuel. Butanol has a higher energy content than ethanol and can be used in conventional gas engines without modifications. Unfortunately, the fermentation pathway for butanol production is restricted by its toxicity to the microbial strains used in the process. Butanol is toxic to the microbes, and this can slow fermentation rates and reduce butanol yields. Gas stripping technology can efficiently remove butanol from the fermentation broth as it is produced, thereby decreasing its inhibitory effects. Traditional butanol separation heavily depends on the energy intensive distillation method. One of the main issues in acetone-butanol-ethanol fermentation …

Processing, Microstructure, And Mechanical Properties Of Zirconium Diboride-Molybdenum Disilicide Ceramics And Dual Composite Architectures, Ryan Joseph Grohsmeyer

Doctoral Dissertations

"This research had two objectives: characterization of processing-microstructure-mechanical property relationships of conventional ZrB₂-MoSi₂ ceramics at room temperature (RT) and 1500⁰C in air, and fabrication of ZrB₂-MoSi₂ dual composite architectures (DCAs) for use near 1500⁰C. Elastic moduli, fracture toughness, and flexure strength were measured at RT and 1500⁰C for 15 ZrB₂-MoSi₂ ceramics hot pressed using fine, medium, or coarse ZrB₂ starting powder with 5-70 vol.% MoSi₂, referred to as FX, MX, and CX respectively where X is the nominal MoSi₂ content. MoSi₂ decomposed during sintering, resulting in …

Understanding The Deformation Mechanisms In Nanostructured Metals By A Novel Discrete Crystal Plasticity Finite Element Model, Rui Yuan

Doctoral Dissertations

"Implementation of nanostructured metals and alloys for use in engineering applications requires a detailed knowledge of the underlying deformation mechanisms in these materials. It is well known that plastic deformation in metals and alloys is mainly mediated by dislocation activities. Nonetheless, TEM observations and atomistic simulations indicate that dislocation-mediated plasticity in nanostructured metals and alloys is significantly different from that in their coarse-grained counterparts. Therefore, this dissertation focuses on the exploration of the deformation mechanisms in nanostructured metals via crystal plasticity finite element modeling and simulation.

A statistical grain boundary dislocation source model accounting for dislocation nucleation and slip events …

Experimental And Computational Investigation Of Multi-Principal Element Alloys, Mohsen Beyramali Kivy

Doctoral Dissertations

"Multi-principal element (MPE) alloys, unlike traditional alloys, consist of five or more principal elements with near equi-atomic compositions creating a large new compositional space for exploring new alloy possibilities. However, designing MPE alloys with the desired phases, microstructures and properties is challenging task, and there is a demand for basic research for a better understanding of structure-processing-property relations in these alloys.

In this Ph.D. research, different computational models and experiments were integrated to study phase formations, and mechanical properties of different MPE alloys. Density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations were used to determine crystal structures, …

Dirac Surface States Of Magnetic Topological Insulators, Seng Huat Lee

Doctoral Dissertations

"Magnetic topological insulator (TI) has been theoretically proposed to be a platform for inducing magnetic monopole and exhibit fascinating quantum phenomena, whereas topological superconductor can host Majorana fermions, particles that are their own antiparticles, which can be manipulated for topological quantum computing. In this dissertation, we experimentally demonstrated that by intercalation of different transition metals in the van der Waals gaps of Bi₂Se₃ TI, magnetism and even superconductivity can be induced. In Fe_xBi₂Se₃, antiferromagnetism is induced with a transition temperature at ~ 100 K. Coexistence of the Dirac surface state with …

Study Of Stability And Thermal Conductivity Of Nanoparticles In Propylene Glycol, Sumit Mahajan

All Graduate Theses, Dissertations, and Other Capstone Projects

This thesis studied the effects of gravity induced settling, thermophoresis and Brownian motion on the thermal conductivity of the Aluminum Oxide (Al2O3) nanofluids. The base fluid was propylene glycol. The effects were studied by making three samples with volumetric percentages of 0.2 %, 2% and 3% Al2O3 in propylene glycol. Sets of 22 experiments were conducted over time to understand the behavior of settling. All samples were manually mixed each time the experiment was conducted. A Thermtest Transient Plane Source TPS 500S was used to measure the thermal conductivity. Volumetric percentages and diameters of nanoparticle were chosen so that the …

Dynamic Analysis For Characterization Of Novel Biomass Based Composities, Aarsh Jigish Shah

Electronic Theses and Dissertations

Resources from forests constitute a significant asset of Mississippi State. Forests cover around 19.7 million acres (65%) of the total land area of Mississippi. Total annual economic impact of Mississippi’s forest products is about $17 billion. Creation of high-value products will lead to a number of economic benefits to the region. This work focuses on the study of bio-composite. Bio-composite materials are a ‘Green’ alternative to conventional materials which are readily recyclable and biodegradable. Taylor made properties are achievable in bio-composites, this being one of the significant advantages. Producing biodegradable products has become a necessity due to petroleum-based products being …

Compact Facility For Testing Steady And Transient Thermal Performance Of Building Walls, Aimee Byrne, Gerard Byrne, Anthony Robinson

Articles

Energy efficiency retrofit of buildings represents a key effort in reducing EU energy demand by 20% by 2020. However, predictions tend to overestimate savings by large percentages. The shortfall in savings can be attributed to incorrect predictive techniques, comfort takeback along with other behavioural and workmanship variables. Common predictive techniques related to heat loss tend to be based on the U-value of the building envelope. This paper presents the design of a more straightforward and compact version of the traditional Hot-Box apparatus (measures U-value) which instead determines the thermal resistance of samples of building envelope. U-value includes the need to …

Engineering Of Organic Nanocrystals By Electrocrystallization, Mohamed Kilani

Wayne State University Theses

This work discusses the experimental and theoretical methods used to control the morphology of nanocrystals. The hypothesis of the thermodynamic/kinetic control of the morphology was verified. We applied the electrocrystallization to make K(def)TCP nanocrystals and we tuned the electrochemical parameters to determine their influence on the nanocrystals morphologies. The characterization was mainly performed with AFM and FE-SEM. We presented in this work the possibility to control the morphology of K(def)TCP using the electrochemical parameters. The obtained shapes ranged from nanorods to rhombohedral shape, which is reported for the first time. The observed growth behavior was modeled and simulated with a …

Application Of Phase Shifting Electronic Speckle Pattern Interferometry In Studies Of Photoinduced Shrinkage Of Photopolymer Layers, Mohesh Moothanchery, Viswanath Bavigadda, Manojit Pramanik, Vincent Toal, Izabela Naydenova

Articles

Photoinduced shrinkage occurring in photopolymer layers during holographic recording was determined by Phase Shifting Electronic Speckle Pattern Interferometry. Phase maps were calculated from the changes in intensity at each pixel due to the phase differences introduced between object and reference beams. Shrinkage was then obtained from the changes in phase as recording proceeded. The technique allows for whole field measurement of the dimensional changes in photopolymers during holographic recording.

Engineering Crystallization Via Phase Field Crystal Model, Deepak Joshi

Wayne State University Theses

Charge transfer complex material demonstrate morphological transitions while electro-crystallized on a substrate electrode under varying solute concentration and applied overpotential. It is hypothesized that variations in these parameters affect the thermodynamics and the kinetics of the electro-crystallization process. Having analysed these results, we resort to applying phase field crystal(PFC) model for our theoretical study. Our initial literature review laid foundation to consider PFC model as a powerful tool to study various aspect of crystallization process. In a PFC model the thermodynamic state of a system under study is defined in terms of Helmholtz free energy functional of density profile F=F[ρ(r)].Our …

Materials For Giant Spin Hall Effect Devices, Avyaya Jayanthinarasimham

Legacy Theses & Dissertations (2009 - 2024)

Studies presented in this thesis are an effort to control the growth of β W and explore

Development Of Multilayer Titanium Nitride-Based Coatings As Corrosion Resistant Films For Stainless Steel Bipolar Plates In Pem Fuel Cells, Nicholas Padula

Legacy Theses & Dissertations (2009 - 2024)

High cost and short lifetime are the two main reasons why the PEM fuel cell has not reached a widespread, disruptive level of commercialization. Conventional graphite bipolar plates are responsible for about 45% of the cost and 85% of the total weight of a single cell. These measures are linked to difficult machining of thick, brittle graphite and processing needed to render graphite non-porous. Stainless steel is suggested as the replacement bipolar plate material due to its favorable mechanical properties, ease of manufacturing and relatively low price, but requires a cost-effective coating as a non-conductive oxide forms on the bare …

Elucidation And Optimization Of Resistive Random Access Memory Switching Behavior For Advanced Computing Applications, Zahiruddin Alamgir

Legacy Theses & Dissertations (2009 - 2024)

RRAM has recently emerged as a strong candidate for non-volatile memory (NVM). Beyond memory applications, RRAM holds promise for use in performing logic functions, mimicking neuromorphic activities, enabling multi-level switching, and as one of the key elements of hardware based encryption or signal processing systems. It has been shown previously that RRAM resistance levels can be changed by adjusting compliance current or voltage level. This characteristic makes RRAM suitable for use in setting the synaptic weight in neuromorphic computing circuits. RRAM is also considered as a key element in hardware encryption systems, to produce unique and reproducible signals. However, a …

Computational Optimization And Characterization Of Molecularly Imprinted Polymers, Jacob Jordan Terracina

Legacy Theses & Dissertations (2009 - 2024)

Molecularly imprinted polymers (MIPs) are a class of materials containing sites capable of selectively binding to the imprinted target molecule. Computational chemistry techniques were used to study the effect of different fabrication parameters (the monomer-to-target ratios, pre-polymerization solvent, temperature, and pH) on the formation of the MIP binding sites. Imprinted binding sites were built in silico for the purposes of better characterizing the receptor – ligand interactions. Chiefly, the sites were characterized with respect to their selectivities and the heterogeneity between sites.

Exploring Magnetic Nanostructures Embedded Within Single-Crystal Silicon For Generation Of Spin-Polarized Carriers, Machara Krishna Girish Malladi

Legacy Theses & Dissertations (2009 - 2024)

Integrating magnetic functionalities with silicon holds the promise of developing, in the most dominant semiconductor, a paradigm-shift information technology based on the manipulation and control of electron spin and charge. Here, we demonstrate an ion implantation approach enabling the synthesis of a ferromagnetic layer within a defect free Si environment by exploiting an additional implant of hydrogen in a region deep below the metal implanted layer. Upon post-implantation annealing, nanocavities created within the H-implanted region act as trapping sites for gettering the implanted metal species, resulting in the formation of metal nanoparticles in a Si region of excellent crystal quality. …

Homo- And Heterometallic Bis(Pentafluorobenzoyl)Methanide Complexes Of Copper(Ii) And Cobalt(Ii), Janell Crowder

Legacy Theses & Dissertations (2009 - 2024)

β-Diketones are well known to form metal complexes with practically every known metal and metalloid. Metal complexes of fluorinated β-diketones generally exhibit increased volatility and thermal stability compared to the non-fluorinated analogues, and thus are used extensively in various chemical vapor deposition (CVD) processes for the deposition of metal, simple or mixed metal oxides, and fluorine-doped metal oxide thin films. Furthermore, the electron-withdrawing nature of the fluorinated ligand enhances the Lewis acidity of a coordinatively unsaturated metal center which facilitates additional coordination reactions. The physical and structural properties of fluorinated β-diketonate complexes are discussed in Chapter 1 …

Effect Of Ion Flux (Dose Rate) In Source-Drain Extension Ion Implantation For 10-Nm Node Finfet And Beyond On 300/450mm Platforms, Ming-Yi Shen

Legacy Theses & Dissertations (2009 - 2024)

The improvement of wafer equipment productivity has been a continuous effort of the semiconductor industry. Higher productivity implies lower product price, which economically drives more demand from the market. This is desired by the semiconductor manufacturing industry. By raising the ion beam current of the ion implanter for 300/450mm platforms, it is possible to increase the throughput of the ion implanter. The resulting dose rate can be comparable to the performance of conventional ion implanters or higher, depending on beam current and beam size. Thus, effects caused by higher dose rate must be investigated further. One of the major applications …

Modeling And Studying The Effect Of Texture And Elastic Anisotropy Of Copper Microstructure In Nanoscale Interconnects On Reliability In Integrated Circuits, Adarsh Basavalingappa

Legacy Theses & Dissertations (2009 - 2024)

Copper interconnects are typically polycrystalline and follow a lognormal grain size distribution. Polycrystalline copper interconnect microstructures with a lognormal grain size distribution were obtained with a Voronoi tessellation approach. The interconnect structures thus obtained were used to study grain growth mechanisms, grain boundary scattering, scattering dependent resistance of interconnects, stress evolution, vacancy migration, reliability life times, impact of orientation dependent anisotropy on various mechanisms, etc. In this work, the microstructures were used to study the impact of microstructure and elastic anisotropy of copper on thermal and electromigration induced failure.

Nonlinear Dielectric Behavior Of Field-Induced Antiferroelectric/Paraelectric-To-Ferroelectric Phase Transition For High Energy Density Capacitor Application, Mingyang Li

Dissertations, Master's Theses and Master's Reports

Electric field-induced antiferroelectric(AFE)/paraelectric(PE)-to-ferroelectric(FE) phase transitions are investigated for the associated nonlinear dielectric behavior, which could offer high dielectric capacity. The phenomenon in monolithic materials has been computed for Kittel antiferroelectric and BaTiO₃ model systems using the Landau-Ginzburg-Devonshire theory. The general switching curves give values of the polarization as a function of external electric field. A similar computation is performed for particle-filled polymer-matrix composites where an internal depolarization field is considered. The polarization-electric field response changes with different depolarization factors, which demonstrate the shape and alignment of the dielectric particles embedded in polymer-matrix are key factors for the composite to …