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Articles 781 - 810 of 16783
Full-Text Articles in Entire DC Network
Process Intensification For Rare Earth Elements Adsorption By Resonant Vibratory Mixing (Rvm), Mehran Saddat
Process Intensification For Rare Earth Elements Adsorption By Resonant Vibratory Mixing (Rvm), Mehran Saddat
Graduate Theses & Non-Theses
Rare earth elements (REE) are crucial to the advancement of modern technologies. REE applications include electronics, defense systems, wind turbines, catalysts, magnets, and aircraft. Bastnasite, monazite, and xenotime are the primary resources, while the secondary resources, including coal ash, E-waste, and acid mine drainage, are for REE extraction. The primary processing techniques are chemical leaching, ion exchange, chemical precipitation, pyrometallurgy, solvent exchange, biosorption, and adsorption. Adsorption technique is simple, cost-effective, and environmentally friendly, with higher efficiency but at the cost of a longer mixing time. Therefore, there is a pressing need for an optimized mixing technique to improve the adsorption …
Production Of Rare Earth Elements By Molten-Salt Electrolysis, Mohammed Moro
Production Of Rare Earth Elements By Molten-Salt Electrolysis, Mohammed Moro
Graduate Theses & Non-Theses
Rare earth elements (REEs) are indispensable, high-value resources that play a crucial role in renewable energy, defense systems and advanced technological systems. REEs are commonly extracted from natural ores or recycled materials such as permanent magnets using hydrometallurgical or pyrometallurgical techniques. In hydrometallurgy, the REE source is leached with acid, followed by solvent extraction and precipitation steps to obtain rare earth compounds like oxides and fluorides. Pyrometallurgy involves dissolving rare earth compounds in a molten halide bath, followed by high-temperature electrolysis to convert them into metals, which are then recovered at the cathode. This process typically includes melting, refining, and …
Concerted Rattling-Induced Strong Anharmonicity And Phonon Coherence Lead To Ultralow Glasslike Thermal Conductivity In Tlagte, Shantanu Semwal, Yi Xia, Chris Wolverton, Koushik Pal
Concerted Rattling-Induced Strong Anharmonicity And Phonon Coherence Lead To Ultralow Glasslike Thermal Conductivity In Tlagte, Shantanu Semwal, Yi Xia, Chris Wolverton, Koushik Pal
Mechanical and Materials Engineering Faculty Publications and Presentations
Ordered crystalline compounds exhibiting ultralow and glass-like thermal conductivity are both fundamentally and technologically important, where phonon quasi-particles dominate their heat transport. Understanding the microscopic mechanisms that govern such unusual transport behavior is necessary to unravel the complex interplay of crystal structure, phonons, and collective excitations of these quasi-particles. Here, we use state-of-the-art first-principles calculations based on quantum density functional theory to investigate the origin of experimentally measured unusually low and glassy thermal conductivity in semiconducting TlAgTe that possesses disconnected chains of Tl atoms within its three-dimensional crystalline framework made up of distorted AgTe4 tetrahedra. Utilizing a unifying framework of …
Study Of Isocyanate-Free Vegetable Oil-Based Polyurethane Coating With A Silicon-Based Compound For Coating Properties, Ajay Kumar
Electronic Theses & Dissertations
The development of sustainable and environmentally friendly polyurethane coatings has garnered significant attention in recent years. This research focuses on the development of isocyanate-free coatings derived from carbonated soybean oil (CSBO) using a solvent- and catalyst-free approach. The coatings were synthesized by reacting CSBO with ethylenediamine (EDA) and varying weight percentages of 3-aminopropyltriethoxysilane (APTES), which were added to enhance the coating property, as it contains silicon in it, to evaluate their mechanical and thermal properties. Fourier Transform Infrared Spectroscopy (FTIR) confirmed the successful formation of urethane linkages, with a significant reduction in C=O peak intensity after 10 days of curing, …
In-Situ Investigations Of Calcium-Magnesium-Aluminosilicates (Cmas) Infiltration Effects On Thermal Barrier Coatings Under Extreme Environments Replicating Jet Engines, Zachary Stein
Doctoral Dissertations and Master's Theses
Calcium-magnesium-aluminosilicate (CMAS) particulates, such as sand or volcanic ash, are ingested by gas turbine jet engines during operation. When operating within high abundance regions, these particulates negatively interact and degrade the high temperature thermal barrier coatings (TBC) protecting underlying superalloy turbine blades vital to engine operation. These CMAS particulates melt within the engine and infiltrate into the ceramic coatings. In electron-beam physical vapor deposited (EB-PVD) TBCs, the CMAS within the intercolumnar gaps stiffens the coatings and causes thermomechanical induced high stress concentrations, risking crack formation. While molten, the CMAS thermochemically alters and destabilizes the coating, also risking coating failure. Premature, …
Influence Of Build Plate Location On Tensile Properties And Residual Stresses In Lpbf-Fabricated Stainless Steel 316 Components, Yareli Zelaya Pavón
Influence Of Build Plate Location On Tensile Properties And Residual Stresses In Lpbf-Fabricated Stainless Steel 316 Components, Yareli Zelaya Pavón
Honors Program Theses and Research Projects
Additive manufacturing (AM), particularly Laser Powder Bed Fusion (LPBF), enables rapid production of complex metal components with minimal waste. Stainless Steel 316 (SS316) is widely used in engineering applications due to its corrosion resistance and mechanical reliability. This study investigates the influence of build plate location on tensile properties and residual stresses in LPBF-fabricated SS316. Twelve tensile specimens and nine unsupported bridge structures were fabricated at different build plate positions using a “machine model.” Tensile testing provided stress-strain data to evaluate peak stress, elastic modulus, and strain at break, while bridge curvature measurements quantified residual stress through warping. Results indicate …
Building Enveloperetrofitting Innovation: Recycled Materials Role In Digital Fabrication And 3d Printing, Amr Soliman Elgohary, Haytham M. Elbadrawy, Ahmed Elsamanoudi
Building Enveloperetrofitting Innovation: Recycled Materials Role In Digital Fabrication And 3d Printing, Amr Soliman Elgohary, Haytham M. Elbadrawy, Ahmed Elsamanoudi
HBRC Journal
Traditional construction methods are one of the main causes of resource depletion. This research explores the intersection of digital fabrication methods using recycled materials and eco-friendly construction through retrofitting the building envelope to achieve sustainability. Traditional methods of retrofitting existing building elements consume many resources (materials-energy) and produce a lot of waste. In this context, 3D printing, a modern digital manufacturing method, stands out as a promising alternative, offering innovative ways to reduce material and energy consumption and reduce waste in the building construction process. This technique can be used to produce innovative modules that may improve the environmental performance …
Imaging Of Dynamic Processes In Materials With A Laser-Wakefield Accelerator, J. Kang, R. J. Shalloo, M. J. Higgins, S. J.D. Dann, J. N. Gruse, C. I.D. Underwood, A. F. Antoine, C. Arran, C. D. Baird, M. D. Balcazar, N. Bourgeois, J. A. Cardarelli, K. Krushelnick, S. P.D. Mangles, C. D. Murphy, N. Lu, P. P. Rajeev, M. P. Selwood, D. R. Symes, C. P. Ridgers, A. G.R. Thomas, C. Thornton, Z. Najmudin, P. G. Sanders, P. D. Staublin, A. J. Shahani, M. J.V. Streeter
Imaging Of Dynamic Processes In Materials With A Laser-Wakefield Accelerator, J. Kang, R. J. Shalloo, M. J. Higgins, S. J.D. Dann, J. N. Gruse, C. I.D. Underwood, A. F. Antoine, C. Arran, C. D. Baird, M. D. Balcazar, N. Bourgeois, J. A. Cardarelli, K. Krushelnick, S. P.D. Mangles, C. D. Murphy, N. Lu, P. P. Rajeev, M. P. Selwood, D. R. Symes, C. P. Ridgers, A. G.R. Thomas, C. Thornton, Z. Najmudin, P. G. Sanders, P. D. Staublin, A. J. Shahani, M. J.V. Streeter
Michigan Tech Publications
Betatron x rays generated from laser-wakefield accelerators are a promising source for imaging dynamic processes in materials. Here, we present proof-of-concept imaging of microstructural evolution in a hypermonotectic Al-Bi alloy, which consists of liquid Bi particles in a solid Al matrix. The images capture the elongation and fragmentation of Bi particles upon isothermal annealing. Because of the femtosecond time scale of the betatron source, the images are not subject to motion blur, whereas the accessibility of the source allows for studies of long-term processes such as annealing. The high-resolution data reveal that the evolution of Bi particles is mediated by …
Production Of Recombinant Β-Galactosidase Protein In Bombyx Mori (Bmn1) Baculovirus Insect Cells, Shuhrat Sh. Khasanov, Jumanazar Ch Mengturayev, Jaloliddin M. Abdurakhmanov, Dilmurodjon B. Turdaliyev, Shakhnoz S. Azimova
Production Of Recombinant Β-Galactosidase Protein In Bombyx Mori (Bmn1) Baculovirus Insect Cells, Shuhrat Sh. Khasanov, Jumanazar Ch Mengturayev, Jaloliddin M. Abdurakhmanov, Dilmurodjon B. Turdaliyev, Shakhnoz S. Azimova
CHEMISTRY AND CHEMICAL ENGINEERING
In this study we aimed to obtain a novel recombinant β-galactosidase baculovirus using the Bombyx mori baculovirus – insect cell expression system. A new recombinant plasmid was constructed on the basis of the pBacPAK8 transfer vector and cloned in E. coli cells. Subsequently, a recombinant baculovirus was generated in Bombyx mori cells, and efficient expression of the β-galactosidase gene was observed. The enzymatic activity of the protein was confirmed by the ONPG assay. The results demonstrated that the baculovirus – insect cell system expands the possibilities for producing proteins of industrial significance.
Photocatalytic Activity Of The Mixed Of Ti/Fe/Mo Oxide Composites For Degradation Of Nitrofurazone, Dilshoda R. Tursunova, Zuhra Ch. Kadirova, Shahlo Sh. Daminova, Kadriya Kh. Gabidullina
Photocatalytic Activity Of The Mixed Of Ti/Fe/Mo Oxide Composites For Degradation Of Nitrofurazone, Dilshoda R. Tursunova, Zuhra Ch. Kadirova, Shahlo Sh. Daminova, Kadriya Kh. Gabidullina
CHEMISTRY AND CHEMICAL ENGINEERING
The aim of study is synthesize mixed oxide composites based on titanium dioxide, iron and molybdenum oxides from industrial waste materials and evaluated for their photocatalytic degradation performance of nitrofurazone—a persistent and toxic antibiotic frequently detected in aquatic environments. Various Ti/Mo ratios (T95M5, T87.5M12.5, T75M25, and T50M50) were prepared through thermal treatment at 600 °C and characterized using XRD, UV–Vis and Raman spectroscopy to assess structural and optical properties.XRD and Raman analyses confirmed the presence of anatase-phase TiO₂ and Mo/Fe oxides, with optimal crystallinity and heterojunction formation observed in the T87.5M12.5 composite. UV–Vis spectroscopic studies demonstrated that this composite exhibited …
Gas Chromatographic Analysis Of Fractions Separated By Atmospheric Distillation Of Pyrolysis Distillate, Gulnora K. Komolova, Lola A. Yusupova
Gas Chromatographic Analysis Of Fractions Separated By Atmospheric Distillation Of Pyrolysis Distillate, Gulnora K. Komolova, Lola A. Yusupova
CHEMISTRY AND CHEMICAL ENGINEERING
The primary objective of this study is to optimize the process of isolating the C9 hydrocarbon fraction from pyrolysis distillate and to evaluate the impact of various temperature regimes on the product composition. To achieve this goal, the dry distillation process was conducted at three different temperatures: 152 °C, 159 °C, and 170 °C. Condensate samples obtained from each test were analyzed using gas chromatography (GC). The analysis results revealed that the fraction obtained at 152 °C yielded the most favorable outcome: the C9 fraction yield was 11.11%, which is higher than the values obtained at 159 °C (4.59%) and …
Lightweight Thermal Insulation Brick Based On Jerdanak Clay Shale, Obtained With The Addition Of Sawdust, Mastura Kh. Aripova, Sarvar T. Bozorov
Lightweight Thermal Insulation Brick Based On Jerdanak Clay Shale, Obtained With The Addition Of Sawdust, Mastura Kh. Aripova, Sarvar T. Bozorov
CHEMISTRY AND CHEMICAL ENGINEERING
The aim of this study was to produce lightweight thermal insulation bricks based on Djerdanak clay shale with the addition of wood sawdust. The starting materials were clay shale from the Djerdanak deposit, fireclay made from it, and wood chips—a waste product from the wood processing industry. The optimal brick composition was determined to include 60% clay shale, 40% fireclay made from clay shale, and 14% wood chips (over 100%). The apparent density of the optimal brick composition corresponds to an apparent product density of 1 g/cm³ and a compressive strength of 3.6 N/mm². The microstructure of the material demonstrates …
Waste Utilization Considering Volatiles Circulation Behavior In Cement Kilns, Geun-Seong Lee, Farrukh B. Erkinov, Zebo A. Babakhanova, Mukhammadamin Sh. Jololdinov, Mastura Kh. Aripova
Waste Utilization Considering Volatiles Circulation Behavior In Cement Kilns, Geun-Seong Lee, Farrukh B. Erkinov, Zebo A. Babakhanova, Mukhammadamin Sh. Jololdinov, Mastura Kh. Aripova
CHEMISTRY AND CHEMICAL ENGINEERING
Since the cement kiln process has various advantages for waste incineration, the waste utilization as alternative fuel has been widely applied in the cement process. For waste utilization in kiln process, it is necessary to operate within the range of not-affecting the clinker quality and the operation stability, and not-causing pollution problems, with ensuring the smooth clinker production. In order to quantitatively analyze the volatiles circulation phenomena during waste utilization as alternative fuel in the kiln process, the simplified volatiles circulation model is derived based on material balances of volatiles, from which the permissible waste utilization % as alternative fuel …
Physico-Chemical Study Of Interaction In The “Urea – Glycine – Water” System, Suvonkul E. Nurmonov, Saydullo Kh. Azimov
Physico-Chemical Study Of Interaction In The “Urea – Glycine – Water” System, Suvonkul E. Nurmonov, Saydullo Kh. Azimov
CHEMISTRY AND CHEMICAL ENGINEERING
A comprehensive physicochemical study of the aqueous “urea – glycine” system was conducted to establish the mechanisms of intermolecular interaction and stability parameters for the development of modified liquid nitrogen fertilizers (LNF). Isomolar series, visual-polythermal analysis, X-ray phase analysis (XRD), single-crystal X-ray diffraction (SC-XRD), IR spectroscopy, and thermal analysis (DTA/TGA) methods were applied. It was found that the interaction of components in solution leads to the formation of molecular associates stabilized by hydrogen bonds. The XRD and SC-XRD methods confirmed that no new individual chemical compounds are formed in the solid phase. It was proven that the addition of glycine …
Unlocking The Industrial Potential Of Khojaykon Sylvinite Through Mineralogical And Chemical Investigations, Elyor D. Eminov, Kholtura Ch. Mirzakulov, Gavkhar E. Melikulova, Ruslan Ch. Yorbobaev, Kamola S. Arifdjanova
Unlocking The Industrial Potential Of Khojaykon Sylvinite Through Mineralogical And Chemical Investigations, Elyor D. Eminov, Kholtura Ch. Mirzakulov, Gavkhar E. Melikulova, Ruslan Ch. Yorbobaev, Kamola S. Arifdjanova
CHEMISTRY AND CHEMICAL ENGINEERING
The purpose of this study is to analyze the chemical, mineralogical, and fractional composition of sylvinite from the Khodjaikan deposit in Uzbekistan in order to assess its potential for potassium fertilizer production. Using chemical analysis, XRD, and IR spectroscopy, the ore was found to contain KCl (19.5–30.1%), NaCl (62.08–71.85%), CaCl₂ (1.12–1.32%), and MgCl₂ (0.18–0.32%). The water-insoluble residue, mainly sulfates, carbonates, and silicates, was also identified. These findings are important for improving beneficiation processes and reducing waste. Comparison with the Verkhnekamsk deposit highlights the quality and potential of Khodjaikan sylvinite. The research supports sustainable resource management.
Changes In The Structure And Properties Of Titanium In The Process Of Pressure Treatment, Sardor S. Abriev, Nasiba U. Abduraimova, Zokir R. Akramov, Yulbarskhon N. Mansurov
Changes In The Structure And Properties Of Titanium In The Process Of Pressure Treatment, Sardor S. Abriev, Nasiba U. Abduraimova, Zokir R. Akramov, Yulbarskhon N. Mansurov
CHEMISTRY AND CHEMICAL ENGINEERING
Titanium is classified as a critical metal. It serves as a raw material for a wide range of industries owing to its unique properties – high strength at low density, corrosion resistance, and biocompatibility makes it indispensable. Uzbekistan and China possess primary resources for titanium production. However, the complexity of extraction and particularly processing, combined with high production costs, limits its large-scale use and increases the risk of shortages in industrial manufacturing. In this study, the structural and property evolution of titanium during pressure-based processing was investigated. Technology for producing powder titanium by metal forming methods is proposed. The results …
The Structure And Properties Of Er2o3 And Yb2o3 Based Ceramic Materials, Sintered Under High Pressure, Vladimir S. Urbanovich, Vadim D. Zhivulko, Eygeniy N. Poddenezhny, Ekaterina E. Trusova, Vladimir S. Niss
The Structure And Properties Of Er2o3 And Yb2o3 Based Ceramic Materials, Sintered Under High Pressure, Vladimir S. Urbanovich, Vadim D. Zhivulko, Eygeniy N. Poddenezhny, Ekaterina E. Trusova, Vladimir S. Niss
CHEMISTRY AND CHEMICAL ENGINEERING
The aim of the work was to obtain high-density optically transparent ceramic samples by sintering cubic modification Er2O3 and Yb2O3 oxides micropowders at the pressure of 7 GPa and the heating current power of 0.6–1.0 kW, which was demonstrated. Non-monotonic dependence of the density on the heating current power has been established. The maximum density values of 9.2 g/cm3 (Er2O3) and 9.8 g/cm3 (Yb2O3) were achieved at the power of 0.8 and 0.9 kW, respectively. During sintering, the cubic phase partially transforms into the …
Additive Manufacturing Of Carbons From Commodity Polyolefins, Paul Smith
Additive Manufacturing Of Carbons From Commodity Polyolefins, Paul Smith
Dissertations
Though tremendous progress has been made engineering carbon materials across length-scales from the molecular to the macroscopic, on-demand macro-structural control of carbons is still developing. Many carbon materials like graphene, carbon nanotubes, activated carbons, and carbon fibers have powder or fiber form factors. Recent research has pioneered on-demand carbon production through additive manufacturing (AM) via 1) extrusion and post-processing of highly filled carbon slurries, or 2) printing and pyrolysis of polymeric carbon precursors such as polyimides, acrylated polyethylene glycol, and phenolics. While groundbreaking, most methods face challenges with adoption due to costly/complex materials and manufacturing processes, and large dimensional changes …
Elucidating Differences In Constitutionally Isomeric Diamine- And Bisphenol-Based Polybenzoxazine Networks, Benjamin L. G. Morasch
Elucidating Differences In Constitutionally Isomeric Diamine- And Bisphenol-Based Polybenzoxazine Networks, Benjamin L. G. Morasch
Dissertations
This dissertation aims to expand the fundamental understanding of diamine-based benzoxazine chemistry by examining how synthesis influences the network properties of 4,4’-ddm and phenol-based (P-ddm) benzoxazine, compared to the constitutionally isomeric bisphenol-F and aniline-based (BF-a) benzoxazine. While bisphenol-based benzoxazines such as BF-a have been studied more extensively, diamine-based benzoxazines are still relatively unexplored due to the competition with the formation of 1,3,5-hexahydrotriazine intermediates and the inconsistent thermal and mechanical properties reported in the literature. These inconsistencies stem from factors including synthetic methods, curing conditions, and degradation during polymerization that have been overlooked.
To address these issues, this dissertation is organized …
Upcycling Commodity Polymers To Advanced Materials For Energy And Environmental Sustainability, Anthony Griffin-Espinoza
Upcycling Commodity Polymers To Advanced Materials For Energy And Environmental Sustainability, Anthony Griffin-Espinoza
Dissertations
Synthetic polymers play an essential role in nearly every aspect of our lives. Extending beyond single-use packaging, polymeric material design has progressed to attain tailorable architectures granting exceptional performance across advanced applications, including carbon-fiber reinforced polymer composites for aerospace, conductive materials for soft electronics, and drug carriers for biomedicine. While highly promising, intricately designed polymers needed to achieve excellent performance often have limited processability, complex synthetic methods, and expensive precursors. Furthermore, due to a lack of recyclability, commodity polymer waste streams result in both environmental impacts and a substantial loss of economic value. This dissertation focuses on developing robust strategies …
Understanding Crystallization Behaviors Of Polyethylene-Derived Vitrimers, Sara Valdez
Understanding Crystallization Behaviors Of Polyethylene-Derived Vitrimers, Sara Valdez
Dissertations
Polyolefins (POs), particularly polyethylene (PE) and polypropylene (PP), are among the most widely utilized polymers globally, valued for their low production costs and favorable mechanical properties stemming from their semicrystalline microstructure. However, their extensive use and improper disposal have raised serious environmental and human health concerns. In response, PO-derived covalent adaptable networks (CANs) have emerged, integrating dynamic chemistries to enable recyclability and sustainable end-of-life strategies. While existing literature has largely focused on novel CAN systems, structure–property relationships, and network rearrangement in relation to thermal transitions (e.g., topological freezing temperature), the influence of network formation on crystallinity and crystallization kinetics remains …
Polypropylene/Polyethylene Blends With Asymmetric Viscosity: Fabrication, Characterization, And Recycling Potential, Bernadine Daichendt
Polypropylene/Polyethylene Blends With Asymmetric Viscosity: Fabrication, Characterization, And Recycling Potential, Bernadine Daichendt
All Dissertations
Polyolefin materials, polypropylene (PP) and polyethylene (PE), are widely used in day-to-day life both commercially and industrially, offering versatile applications due to their mechanical and chemical properties. The high consumption rate of these materials makes them important targets for recycling efforts. However, there are multiple contributing factors leading to low recycling of PP and PE, chiefly sorting factors: chemical similarity, changed properties after multiple rounds of processing, and the use of processing aids. It is necessary to point out that, because of multiple melt processing cycles, recycled PP has decreased molecular weight due to chain scission. Conversely, recycled PE molecular …
Micro/Nanomechanical Properties Of Top-Seeded Melt Grown Ybco Single Crystals Determined Using Depth Sensing Indentation, Ugur Kolemen, Cafer Mert Yesilkanat, Fikret Yilmaz, Fatih Dogan, Orhan Uzun
Micro/Nanomechanical Properties Of Top-Seeded Melt Grown Ybco Single Crystals Determined Using Depth Sensing Indentation, Ugur Kolemen, Cafer Mert Yesilkanat, Fikret Yilmaz, Fatih Dogan, Orhan Uzun
Materials Science and Engineering Faculty Research & Creative Works
Mechanical properties of the bulk YBa2Cu3O7-x (YBCO) single crystal superconductor, prepared by using the Top Seeded Melt Growth (TSMG) method, were determined. Property measurements were conducted by the nanoindentation method under various loads and the micro indentation method at different temperatures. Hardness (H) and reduced elastic modulus (Er) values were calculated by using the Oliver–Pharr method. According to hf/h max values found from load- displacement curves, there is a sink in behavior around outer rim of the indents that was confirmed by atomic force microscopy (AFM) analysis. Nanoindentation analyses conducted on upper section, middle section and subsection revealed that all …
Investigating The Performance Of Fibre Reinforced Plastic Repairs To Timber Marine Civil Structures At His Majesty’S Naval Base Devonport, Anna G. Walther
Investigating The Performance Of Fibre Reinforced Plastic Repairs To Timber Marine Civil Structures At His Majesty’S Naval Base Devonport, Anna G. Walther
The Plymouth Student Scientist
This paper explores Fibre Reinforced Plastics (FRPs) as a composite repair method to restore and enhance mechanical properties of timber marine civil structures within the context of His Majesty’s Naval Base (HMNB) Devonport. To support this, timber composite specimens were manufactured and subjected to flexural and compressive strength tests. Comparisons are made to literature sources for initial predictions, in addition to hand calculations and Finite Element Analysis (FEA) models on SolidWorks. Data demonstrates that FRPs can be used as a cost-effective and beneficial method of repairing timber marine structures. Experimental data demonstrates an ability to restore compressive strength parallel to …
Development And Testing Of A Prototype Erbium-Doped Lithium Tantalate Based Sensor For Infrastructure Crack Detection And Measurement, Alejandro Barrera
Development And Testing Of A Prototype Erbium-Doped Lithium Tantalate Based Sensor For Infrastructure Crack Detection And Measurement, Alejandro Barrera
Theses and Dissertations
Ensuring the safety and longevity of infrastructure is crucial to safeguarding communities and preserving economic stability. In this study, the development of a novel sensor for detecting and characterizing cracks in infrastructure, particularly suited for deployment on Unmanned Aerial Vehicles (UAVs), is presented. The device utilizes a laser (operating at 980 nm) for excitation of erbium-doped lithium tantalate nanoparticles that emit 1550 nm wavelength, which stimulates a photodiode for data collection. The data was utilized to collect, process, and reconstruct topological information. The synthesized lithium tantalate nanoparticle samples vary in erbium doping percentages of 0.5%, 3%, and 10%. Experimental evaluation …
Advancements In Visualization, Post-Processing And Ai-Enhanced Modeling Of Multi-Scale Micromechanics For Composite Materials, Joao Guilherme Brites Rei
Advancements In Visualization, Post-Processing And Ai-Enhanced Modeling Of Multi-Scale Micromechanics For Composite Materials, Joao Guilherme Brites Rei
Masters Theses
This study addresses some of the primary deficits of a localization/homogenization workflow for composite materials by focusing on the visualization and enhancement of models based on GMC and HFGMC, with emphasis on their implementation within the NASMAT ecosystem.
This thesis details the development of two dynamic, ParaView-based plugins that convert large hierarchical simulation outputs into interactive insights. While NASMATDiscreteElement systematizes RUC creation with transparent parametrization in a reproducible GUI, NASMATExplorerRUC enables the inspection of deeply nested datasets through accurate cell picking and synchronizes comparisons between parent and child views. Additionally, a shallow U-Net neural network is optimized on HFGMC data …
Synthesis And Characterization Of Chemically Recyclable Polypropylene-Based Covalent Adaptable Networks, Andrii Tiiara
Synthesis And Characterization Of Chemically Recyclable Polypropylene-Based Covalent Adaptable Networks, Andrii Tiiara
All Dissertations
Polyolefins (POs) are inexpensive engineering materials with excellent physical and mechanical properties, accounting for nearly 60% of all thermoplastics. However, large-scale recycling remains limited, with only ~15% undergoing mechanical recovery. This dissertation addresses this challenge by fragmenting and functionalizing polypropylene (PP) chains to generate macromonomers and employing them, along with industrial reactive PP macromonomers, to synthesize, depolymerize, and repolymerize chemically recyclable polypropylene-based polyolefins (CR-POs). These CR-POs incorporate ester linkages that form covalent adaptable networks (CANs), maintaining a gel fraction of ~70% while remaining melt-reprocessable via extrusion and compression molding.
First, the fragmentation of PP is investigated by microwave irradiation. Microwave …
Further Evaluation Of Speed Tables On Roadway Curves: Simulation And Expeditionary Deployments, Nathan Reineke
Further Evaluation Of Speed Tables On Roadway Curves: Simulation And Expeditionary Deployments, Nathan Reineke
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
The road network leading up to a United States military base is known as an Entry Control Facility, or ECF. Entry control facilities are used to shield military installations by monitoring vehicles and refusing access to unauthorized vehicles. Passive control devices, including speed tables, are used to disrupt or delay threat vehicles attempting to navigate ECFs at high speeds. The purpose of this research was to recommend optimized configurations of speed tables in combination with roadway curves which allow safe, efficient traversal for authorized vehicles and disruption or delay for threat vehicles.
First, an analytical model of a Tesla Model …
Integrating Dft And Machine Learning To Predict Structural Properties In High Entropy Alloys, Nathan Linton
Integrating Dft And Machine Learning To Predict Structural Properties In High Entropy Alloys, Nathan Linton
All Dissertations
In the past decade, a paradigm shift in the design of metal alloys has been observed. These new alloys are commonly referred to as high entropy alloys (HEAs), multi-principal element alloys (MPEAs), or complex, concentrated alloys (CCAs). In contrast to conventional alloys, which consist of one main element (for example 80%) with other elements in small amounts, HEAs are made of four or more main elements ranging from 5 to 35% each element. Due to the large presence of multiple elements, HEAs have shown substantial material property improvements over conventional alloys such as steel. For example, they have high ductility …
Processing-Driven Crystallization, Morphology, And Mechanics In Pekk Composites, Nicholas Ryan Enos
Processing-Driven Crystallization, Morphology, And Mechanics In Pekk Composites, Nicholas Ryan Enos
Dissertations
This dissertation aims to understand how thermoplastic composites can be processed at faster manufacturing rates while identifying how processing variables influence crystallization, morphology, and mechanical properties. Throughout this dissertation, the influence of nano-scale additives, carbon fibers, rapid cooling, shear, and molecular weight on polymer physics, crystallization, morphology, and mechanics is investigated.
The inclusion of carbon nanotubes and graphene nanoplatelets accelerated crystallization, increased nucleation density, reduced lamellar thickness, and shifted governing Hoffman-Lauritzen growth regimes in PEKK. Velisaris-Seferis modelling identified a surface-induced nucleation mechanism in PEKK nanocomposites, and fast scanning calorimetry allowed for the study of rapid cooling rates, helping to identify …