Chemical Engineering Commons^™

Electroless Deposition And Galvanic Displacement For The Control Of Supported Nanoparticle Size And Composition, Haiying Zhou

Theses and Dissertations

Catalyst performances can be greatly affected by properties such as particle size, composition, geometry, and cleanliness of the active surface. To achieve optimal catalytic performance, appropriate synthesis methods are required to synthesize the desired structures. Supported metal particle catalysts are usually prepared by impregnation and precipitation methods in industry. Although these two methods are simple, they exhibit poor control over surface morphology, leading to a wide particle size distribution and uncontrolled distribution of different metal components. In this dissertation, three topics on controlling surface morphology are discussed.

For structure sensitive reactions, reactivity and selectivity can be strongly affected by particle …

Rational Catalyst Synthesis For Sustainable Energy Applications, Alaba Upe Ojo

Theses and Dissertations

Energy accounts for two-thirds of the global climate challenges. Effective utilization of green hydrogen or finding cleaner ways to improve energy generation is necessary to combat climate crisis and allow for a more sustainable future. This work evaluates three heterogeneous catalytic processes which contribute to a sustainable future. In chapter 2, we studied the hydrogenation of toluene to methylcyclohexane; a reaction that can potentially serve as a medium for hydrogen storage and help to overcome the safety challenges of transporting gaseous hydrogen. We found that palladium catalysts on certain carbons exhibited significantly enhanced toluene hydrogenation rates compared to activated carbons …

Injectable Hydrogels That Can Measure Radiation At Body Temperature, Daniel Joseph Ball

Theses and Dissertations

Hydrogel-based radiation dosimeters are used to calibrate and validate radiation delivered by linear accelerators used in radiotherapy. Specifically, Fricke hydrogel-based dosimeters containing ferrous ion complexes oxidize upon exposure to radiation, leading to a change in optical density that can be measured via a color change in a photometric reagent. While gelatin-based Fricke hydrogels are routinely used to measure radiation, these hydrogels are unstable at body temperature, and it is currently not possible to noninvasively measure radiation dose inside a patient. This study reports the synthesis and characterization of self-forming hydrogels containing Fricke components that are stable at body temperature. The …

Use Of Pulsed Electric Fields And Hydrogen Peroxide For Pre And Postharvest Strategies To Reduce Microbial Loads On Fresh Produce, Zachary Rosenzweig

Theses and Dissertations

Several issues exist within the agricultural industry surrounding failure to prevent pathogen transfer to plants preharvest and failure to decontaminate foods postharvest. Fresh produce, like leafy greens, pose a large threat to public safety if contaminated because they are minimally processed and often eaten raw. Numerous outbreaks have been linked to fresh produce in recent decades, with irrigation water emerging as a potential source. These outbreaks have severe economic repercussions and can contribute to millions of hospitalizations and deaths each year, worldwide. This thesis focuses on the usage of pulsed electric fields (PEF) and hydrogen peroxide (H2O2) as a means …

Development Of Bio-Based Organogels For The Replacement Of Silicone Elastomers In Cosmetic & Personal Care Applications, Courtney A. Lemasney

Theses and Dissertations

Silicone elastomers (SE) are a major component in many cosmetic and personal care products, providing excellent spreading properties, leaving a dry, silky feel on the skin. Unfortunately, the manufacturing of silicone is a high energy consuming process, and these products are not biodegradable. Capryloyl/glycerin/sebacic acid (CGS) copolymers are an economical, nontoxic platform for synthesizing bio-based materials with tailored properties. These polyester networks are formed through esterification with water as its only side product. By altering feed ratios and reaction conditions, final products can vary from branched fluids to highly crosslinked elastomers. This thesis investigated controlling the crosslink density of the …

Chemistry And Processing Of Carbon/Carbon Composites From Furan-Based Polybenzoxazine Resins, Michael Chauby

Theses and Dissertations

Carbon/carbon (C/C) composites are valuable for applications requiring structural integrity at high temperatures. However, their widespread use is limited by high manufacturing costs. Monofunctional furan-based benzoxazine resins were identified as promising candidates for enhancing fabrication efficiency due to their low viscosity, high char yield, and high carbon density. A benzoxazine monomer synthesized from furfurylamine, formaldehyde, and benzyl alcohol (Bz-FA-H) exhibits a crosslinking reaction between the furan group and the hydroxymethyl para substituent on the phenol, not found with other monomers. An investigation using blends of monomers containing Bz-FA-H at various concentrations showed that increasing crosslink density resulted in increased bulk …

Guiding 3d Chiral Self-Assembly At Nano/Micro Length Scales Via 3d Printing, Mohsen Esmaeili

Theses and Dissertations

This thesis delves into the intricate realm of 3D printing bio-inspired materials with tailored nano/microscale architectures. The first chapter investigates the flow-induced alignment of cellulose nanocrystals (CNC) during 3D printing, employing a microfluidic strategy integrated with polarized optical microscopy (POM). Birefringence measurements under varying conditions reveal the influence of initial CNC suspension structures on flow-induced patterns, particularly in the chiral nematic phase. Hydrodynamic simulations complement experimental findings, elucidating the impact on CNC particle alignment, providing insights for designing 3D printed architectures with internal chirality for advanced applications.

The second chapter explores the 3D printing of complex geometries inspired by Bouligand …

Mathematical Modeling And Reconstruction Of Porous Media To Understand Transport Phenomena For Electrochemical System Applications, Mitchell Sepe

Theses and Dissertations

Alternative power generation has grown significantly in the space of energy production over the last ten years. Development of new technologies to produce energy is vital to the growing need for electricity. Batteries, solar panels, wind turbines, and countless other renewable energy options have been deemed necessary to create an overall greener future. Fuels cells when combined with electrolyzer show a promising system for stationary power generation. Both technologies are comprised of multiple parts in contact that must work together simultaneously to create an ideal environment for catalytic reactions to take place. A crucial component to a properly functioning cell …

A Click Chemistry Amplified Nanopore Assay For High Performance Testing Of Protein Biomarkers In Diseases, Xiaoqin Wang

Theses and Dissertations

Nanopore detection technology enables nanometer-scale single-molecule detection, yielding valuable insights into analyte molecules' properties such as size, shape, charge, and concentration. Due to its label-free nature, high sensitivity, and real-time capabilities, it finds widespread application in genomics, proteomics, drug discovery, and environmental monitoring. Click chemistry, encompassing the attachment of a probe or substrate to a biomolecule, termed bioconjugation, features the copper-catalyzed azide-alkyne cycloaddition as a quintessential reaction, forming a 5-membered heteroatom ring. This study harnesses this reaction to craft single-strand DNA probes for nanopore testing, leveraging copper's catalytic properties for signal amplification. Host-guest reaction, a noncovalent bond between molecules, specifically …

On The Use Of Cfd Modeling And Analytic Methods To Describe Pressure Drop In Highly Dense Structured Adsorbents In Gas Separation Processes And Fundamentals Of Adsorption, Ryan Timothy Sanders

Theses and Dissertations

The scope of this work can be divided into two main thrusts on topics found within adsorption. The first, and primary, topic is the use of CFD and analytical modeling to describe the flow of gas through a parallel, structured adsorbent channel which is described in Chapters 1 and 2. Chapter 1 establishes a non-experimental methodology based on using a 3D Navier-Stokes (NS) computational fluid dynamics (CFD) model in lieu of experiments, for developing 1D axial pressure drop correlations for structured adsorbents with parallel channels. Chapter 2 utilizes the methodology established in Chapter 1 in order to develop a new …

A Study Of Direct Sensitivity Method Solving Optimal Control Problems With Single And Multiple Time Grids With An Application In An Experimental Hybrid System, Hainan Wang

Theses and Dissertations

Computational methods for optimal control are important for dealing with bottlenecks in industries. By implementing optimal operation strategies obtained from the computational methods into dynamic systems, objectives such as saving energy, reducing cost, exploiting potential, and improving efficiency can be achieved. Computational methods for optimal control have been used in a broad range of disciplines, including aeronautics and astronautics, oil and chemical engineering, power systems, clean energy, biomedical engineering, economics, and management. Due to the great application value of optimal control, its computational methods have drawn worldwide attention. Direct methods are most effective in computational methods for optimal control. Direct …

Development Of Dip-Coated Carbon Fibers For Structural Power Composites And Optimization Of Bus Plates For Passively Propagation Resistant Batteries, David Petrushenko

Theses and Dissertations

Increasing demand for lithium-ion batteries in electric vehicles, portable electronics, and electric aircraft is a driving force for the expansion in new battery architectures to achieve higher gravimetric and volumetric efficiencies. In practice, maximizing energy density can be achieved by introducing state-of-the-art materials to increase the capacity of cells or by reducing the system's mass by incorporating lightweight structural materials. An alternative approach is to develop systems capable of performing multiple functions simultaneously that combine mono-functions of the battery and vehicular structure in a multifunctional component capable of storing electrical energy and providing structural support.

The initial focus of this …

The Role Of Furan Moieties On The Thermal Decomposition And Char Formation Of Intrinsically Fire-Resistant Epoxy Thermosets For Composites, Amy E. Honnig Bassett

Theses and Dissertations

Fire-retardant chemicals added to epoxy thermosets used as coatings, adhesives, and fiber-reinforced polymer composites (FRPCs) negatively impact performance and the environment. This dissertation takes a novel approach to mitigate the flammability of these systems by designing intrinsically fire-resistant epoxies via the incorporation of furan moieties. Glycidyl amines based on furfuryl amine and judiciously selected derivatives of furfuryl amine were synthesized to produce furan-based di-epoxies (FDEs) that were cured by anionic polymerization and with amine curing agents. The furan ring was found to impart additional reactivity for cross-linking and to induce char-forming reactions at higher temperatures. More importantly, the placement of …

Machine Learning Approaches To The Exploration Of Ammonia Synthesis Catalysts Utilizing Experimental Data, Rasika Jayarathna

Theses and Dissertations

Traditional heterogeneous catalyst discovery process relies upon human expert-guided experiments based on domain knowledge and human intuition supported by catalyst characterization. However, this process is time and resource-consuming and suffers from human bias. Machine learning (ML) models trained on experimental data have the potential to significantly accelerate this discovery process by guiding experiments to optimize the catalyst performance and increase the understanding of the catalysts. Ammonia synthesis catalysts are a class of catalysts widely investigated in the literature, which has generated decades of experimental data. Moreover, ammonia has been gaining attention since it can be used as a carbon-free next-generation …

Investigation Of Ethane Dehydrogenation And Hydrogenolysis On Pt(111), Pt(211) And Pt(100): Bayesian Quantification And Correction Of Dft-Based Enthalpic And Entropic Uncertainties, Mubarak Bello

Theses and Dissertations

Computational investigations of heterogeneously catalyzed reactions using density functional theory (DFT) are often inaccurate, largely due to uncertainties in the choice of DFT functional (enthalpic uncertainty) and approximations for modeling adsorbate movement along the catalyst surface (entropic uncertainty). This work illustrates that both uncertainties are significant in the investigation of the ethane dehydrogenation (EDH) and hydrogenolysis on Pt catalysts by considering the complete deconstruction of ethane on Pt(111), Pt(211), and Pt(100) using microkinetic modeling (MKM). Hence, this work uses both non-calibrated and Bayesian calibrated MKMs to quantify and correct inaccuracies in macroscopic properties due to both uncertainties. A Bayesian approach …

Exploring Shape Dependency Of Catalysts For Chemical Reactions, Kaveh Shariati

Theses and Dissertations

Recent advancements in the synthesis of nanoparticles, particularly one-dimensional (1D) nanoparticles, have significantly enhanced the catalytic activity of various processes by enabling precise control over their morphologies and exposing unique crystallographic facets. The shape of nanoparticles is closely linked to their chemical, physical, electrical, optical, magnetic, and catalytic properties. This dissertation investigates the impact of 1D nanoparticle catalysts on two distinct and well-known chemical reactions. In the first part of the study, we explore the catalytic activity and selectivity of silver catalysts in the ethylene epoxidation reaction, which are intrinsically linked to their faceting. Silver nanowire catalysts representing Ag(100) and …

Simulation Of A Passive Osmosis-Integrated Electrolyzer For Seawater Electrolysis, Masoomeh Ghasemi

Theses and Dissertations

Efforts to develop direct seawater electrolysis technology have been ongoing due to the need for pure water in electrolysis and the abundance of seawater. However, progress has been hampered by several issues, including competition with the chlorine evolution reaction, higher membrane resistance, corrosion of electrodes, and scaling from multivalent cations [1]. To avoid these issues, our project has proposed a new reactor that integrates passive osmosis (extracting fresh water from seawater) with electrolysis. In this thesis, we will discuss the operation of the osmosis-integrated electrolyzer and show theoretical predictions of the osmotic pressure differential and water flux/velocity profiles under different …

Applications Of Catalytic Ammonia Chemistry: From Low-Pressure Ammonia Synthesis To The Decomposition Of Tritiated Ammonia As A By-Product Of Magnetically Confined Nuclear Fusion, Jennifer Kules Naglic

Theses and Dissertations

Ammonia is the 2nd most produced chemical in the world with vital importance for its use in fertilizer as the global population has grown in accordance with the industrialization of NH3. While 80% of NH3 produced goes to fertilizer, it has gained attention recently as a hydrogen storage and transportation vessel. Industrially, NH3 is produced at high temperatures and pressures which in turn require high electrical input. Turning to a green NH3 cycle with low temperature and pressure membrane reactors for both NH3 synthesis and decomposition would allow for much lower energy input as well as a renewable energy to …

Manufacturing Of Aligned Electrospun Nanofiber Yarns For Their Enhanced Mechanical And Piezoelectric Properties, Adaugo Mary-Frances Enuka

Theses and Dissertations

Electrospinning is a widely used technique for producing nanofibers with diverse applications. This method uses polymer solutions and strong electric fields to generate nano-sized fibers with unique properties. This study presents a novel manufacturing approach that enables the production of electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofiber yarns using an automated parallel track system and an adjustable roll-to-roll collector. This research examines the impact of an automated post-drawing system on the polymer chain orientation, crystallinity, tensile strength, morphology, and piezoelectric properties of PVDF-HFP nanofiber yarn. The results reveal that the post-drawing process significantly improves molecular alignment, increases tensile strength, and enhances the …

Investigating The Feasibility And Mechanisms Of Cold Spray Deposition Of Polymer-Based Powders On Fiber-Reinforced Composite Substrates, Nicholas Beau Mennie

Theses and Dissertations

Fiber-reinforced composites have become important structural components in industries such as aerospace and energy due to their high mechanical strength and relatively light structural weight. However, during operation, these materials can be prone to impact damage and disintegration. Effective protection via metalization and repair of composites would, therefore, reduce the cost and time for replacement parts. Polymer-based cold spray, while a relatively new technique, can be utilized to metalize and possibly repair composite materials subjected to impact-induced damage. In this work, studies involving polymers and composite cold spray were performed to enable the process of safeguarding, enhancing, or repairing various …

Activity Descriptors As Tools For Designing Highly Efficient Electrocatalysts For Water Splitting, Aya Gomaa

Theses and Dissertations

There is an uprising urge to design efficient, active, and durable catalysts to achieve sustainable hydrogen production. The unambiguity of which material should be used pushed the scientific community to devote enormous efforts in exploring different elements with different ratios on trial and error bases. However, the bridge between the theoretical calculation and the experiments introduced a new realm of designing efficient catalysts by introducing the concept of activity descriptors. In the first part of the thesis, the ability to convert waste stainless steel (SS) 316L meshes into highly efficient and durable oxygen evolution reaction (OER) catalysts is demonstrated. The …

Improving Static Cold Storage Life Of The Human Heart Before Transplant, Juan Sebastian Rodriguez Paez

Theses and Dissertations

Organ storage and transportation are critical steps for the success of organ transplantation. Static cold storage (SCS) of hearts for heart transplantation (HTx) remains the standard approach. However, SCS may involve damage to the tissue resulting from extended hypothermic preservation, potentially affecting organ viability. More over, the temperature distribution on and within the heart is unknown during heart transplantation. Therefore, there is an interest to study different stages of the heart transplantation process towards determining the 3D temperature distribution on and within the heart. There could be a possibility of having a hypothermic injury in different parts of the heart …

Synthesis Of Durable Zeolite 13x Insertion Coatings And Scaled-Up Experimental Demonstration For Co2 Capture, Daniel Jamil Hocheimy

Theses and Dissertations

Minimizing the energy requirement for capturing carbon dioxide (CO₂) from post-combustion sources is critical to efficient industrial decarbonization and subsequent mitigation of the effects of climate change. The current portfolio of CO₂ capture technologies includes absorption, membrane separation and packed bed adsorption, which suffer from high energy and temperature requirements, scalability, and location dependency issues. Adsorption-based systems could cater to these concerns; however, their current embodiments primarily use packed adsorbent bed design and electricity-driven vacuum pumps to regenerate them. While simple and easy to fabricate, these designs are not scalable and cannot use heat to regenerate them …

Investigation Of Fault Detection And Redundant Control Strategy For Model Predictive Control Of Distillation Column, Rajalakshmi R

Theses and Dissertations

Model Predictive Controller (MPC) is one of the industrial-ready control systems and an ideal choice for complex, slow-varying, and energy-intense Distillation Columns (DC). However, MPCs are subjected to failures and their performance degrades with faults and disturbances. Hence, there is a need for a redundant control strategy to ensure the continuous operation of MPC-controlled DC, which is investigated in this work.

A pilot-plant binary DC used to separate methanol and water is implemented with a computer-controlled system and is subjected to Pseudorandom Binary Excitation Signals (PRBS). The output response acquired is used to develop a MIMO (Multi-Input Multi- Output) state-space …

Design And Development Of Deep Eutectic Solvent Assisted Pressurized Liquid Extraction Of Nutraceuticals, Harish Babu B

Theses and Dissertations

Over recent decades, the usage of nutraceuticals has been exponentially increasing as alternates to pharmaceutical drugs. However, extraction of these therapeutically significant compounds from their corresponding sources requires the use of volatile organic solvents like hexane, ethanol and chloroform which increases the global warming potential. This problem has been overcome in recent decades by the use of supercritical carbon dioxide (SCO2) as the extraction solvent. Since SCO2 is non-polar in nature, the extraction of polar compounds with better efficiency is questionable.

On the other hand, modernization in solvent engineering has created generations of green solvents like ionic liquids (ILs), deep …

Towards A Fundamental Understanding Of The Polymer Cold Spray Process, Tristan Bacha

Theses and Dissertations

Cold spray technology lends itself as a versatile process to rapidly apply quality polymer coatings to various substrates; barring limited, although clearly demonstrated, success. The limited success of polymer sprays is a result of modern cold spray knowledge originating from studies with metals. Thus, a deeper understanding of how polymers behave in cold spray is needed to make polymer cold spray a commercially viable process. Various tools are used in this dissertation to progress the fundamental understanding of polymer cold spray as it relates to general processing parameters with a focus on characteristics that do not occur in metals. Polymer …

Cancer Treatment By Targeting Hdac4 Translocation Induced By Microsecond Pulsed Electric Field Exposure: Mechanistic Insights Through Kinases And Phosphatases, Zahra Safaei

Theses and Dissertations

Epigenetic modifications, arising from sub-cellular shifts in histone deacetylase (HDAC) activity and localization, present promising strategies for diverse cancer treatments. HDACs, enzymes responsible for post-translational histone modifications, induce these epigenetic changes by removing acetyl groups from ε-N-acetyl-lysine residues on histones, thereby suppressing gene transcription. Within the HDAC group, class IIa HDACs are notable for their responsiveness to extracellular signals, bridging the gap between external stimuli, plasma membrane, and genome through nuclear-cytoplasmic translocation. This localization offers two significant mechanisms for cancer treatment: nuclear accumulation of HDACs represses oncogenic transcription factors, such as myocyte-specific enhancer factor 2C (MEF2C), triggering various cell death …

Development Of A Xenograft For Annular Repair Using Pulsed Electric Field Exposures For Enhanced Decellularization, Prince Mensah Kwaku Atsu

Theses and Dissertations

Severe back injuries and chronic pain necessitate surgical replacement of damaged intervertebral disc (IVD) cartilage in advanced disease stages. Bovine IVD tissue has been exposed to an upper threshold pulsed electric field (PEF) dose, causing cell death without thermal damage to the tissue. Subsequent PEF exposures at lower magnitudes have accelerated the removal of immunogenic biomolecules though electrokinetic extraction using optimized aqueous solutions. This approach yields a natural scaffold, ready for biocompatibility and mechanical strength assessment. The effects of microsecond pulsed electric fields (µsPEF) on primary bovine AF fibroblast-like cells have been characterized in vitro. PEFs of 10 and 100 …

Integrated Computer-Aided Design, Experimentation, And Optimization Approach For Perovskites And Petroleum Packaging Processes, Swapana Subbarao Jerpoth

Theses and Dissertations

According to the World Economic Forum report, the U.S. currently has an energy efficiency of just 30%, thus illustrating the potential scope and need for efficiency enhancement and waste minimization. In the U.S. energy sector, petroleum and solar energy are the two key pillars that have the potential to create research opportunities for transition to a cleaner, greener, and sustainable future. In this research endeavor, the focus is on two pivotal areas: (i) Computer-aided perovskite solar cell synthesis; and (ii) Optimization of flow processes through multiproduct petroleum pipelines. In the area of perovskite synthesis, the emphasis is on the enhancement …

Supported Metal Nanoparticle Synthesis: Precursor Deposition And Agglomeration At Support Surfaces, Edward H. Chandler Jr.

Theses and Dissertations

Catalysis is a critical component of the chemical manufacturing industry. For example, it has been estimated to be essential to more than 90% of the major industrial processes developed during the middle years of the 20^th century.¹ Heterogeneously supported transition metal catalysts in particular have many benefits such as easy separability from the reaction mixture and high thermal stability. One method of synthesizing these is wet impregnation, wherein a metal solution is brought into contact with an oxide- or carbon-based powder. Given optimal environmental conditions, a metal will adhere to the surface through electrostatic means in a process …