Chemical Engineering Commons^™

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 …

Developing Machine Learning And Time-Series Analysis Methods With Applications In Diverse Fields, Muhammed Aljifri

Theses and Dissertations

This dissertation introduces methodologies that combine machine learning models with time-series analysis to tackle data analysis challenges in varied fields. The first study enhances the traditional cumulative sum control charts with machine learning models to leverage their predictive power for better detection of process shifts, applying this advanced control chart to monitor hospital readmission rates. The second project develops multi-layer models for predicting chemical concentrations from ultraviolet-visible spectroscopy data, specifically addressing the challenge of analyzing chemicals with a wide range of concentrations. The third study presents a new method for detecting multiple changepoints in autocorrelated ordinal time series, using the …

Extrusion-Based Additive Manufacturing Of Magnetic Heat Exchange Structures For Caloric Applications, Vaibhav Sharma

Theses and Dissertations

Currently, the commercial building sector accounts for 18% of total U.S. end-use energy consumption, of which almost a third was from on-site combustion of fossil fuels for space and water heating. Magnetic heat pumping (MHP) technology is an energy-efficient, sustainable, environmentally-friendly alternative to conventional vapor-compression cooling technology. Several MHP designs today are predicted to be highly energy efficient, on condition that suitable working materials can be developed. This materials challenge has proven to be daunting due to issues associated with intricate synthesis/post-processing protocols and complications related to shaping the mostly brittle magnetocaloric alloys into thin-walled channeled regenerator structures to facilitate …

Advanced Synthesis And Rational Design Of Support Structures For Nobel Metal Heterogeneous Catalysis: Towards Enhanced Activity And Continuous Processes, Brian R. Clark

Theses and Dissertations

The field of catalysis has a wide-ranging impact. Our group has identified the constant need for improved catalytic activity in high-impact applications such as hydrosilylation and cross-coupling reactions. For these reactions, precious metal catalysts often exhibit markedly better performance than their counterparts, but they can be a significant process cost that decreases overall economic efficiencies. To address this challenge, we explored support structures that can enhance catalytic activity at low metal loadings and improve precious metal recovery through simple filtration. We found that a platinum on graphene nanoplatelet catalyst (PtGNP) synthesized via strong electrostatic adsorption with microwave irradiation (SEA-MW) exhibits …

Synthesis Of Lithium Nickel Cobalt Manganese Oxide (Ncm) Cathodes For Lithium-Ion Batteries, Jethrine H. Mugumya

Theses and Dissertations

There are various ways to produce lithium nickel manganese cobalt oxide (NCM) based cathodes for lithium-ion batteries, among them; co-precipitation synthesis carried out in tank-based reactors followed by lithiation is commonly employed because of its cost-effectiveness and scalability. Although it is the preferred synthesis method, it has several issues and challenges. Discussed in this dissertation are some of these issues as well as potential solutions. Physical and chemical properties of the co-precipitation product such as yield, particle size, morphology, and tap density, depend on various reaction parameters, which include pH, chelating agents, metal salt concentrations, and stirring speed. In the …

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 …

Advancing Polymer Sustainability Through Custom Interpenetrating Polymer Network Synthesis, Processing, And Design, Alexandra Maria Lehman-Chong

Theses and Dissertations

The need for improving polymer sustainability is as ubiquitous as the role of polymers in modern society. Interpenetrating polymer network (IPN) design flexibility offers opportunities for improved polymer sustainability while balancing desired polymer properties for various applications. This work investigates the structure-property-processing relationships of IPNs judiciously designed under the framework of the polymer life cycle. Sustainable polymer design was largely considered at the feedstock and manufacturing stages while considering overall polymer performance. Chemicals from bio-based feedstocks were used to design a full simultaneous polybenzoxazine-epoxy IPN, focusing on the effects of monomer and polymer structure on polymer properties. Processing-property relationships were …

A Systems Approach To Process Design And Sustainability - Synergy Via Pollution Prevention, Control, And Source Reduction, Emmanuel Apau Aboagye

Theses and Dissertations

Historically, process design prioritized efficiency and profitability, often overlooking environmental and societal implications. However, given the global challenges like climate change and resource scarcity, there is a growing emphasis on embedding sustainability into process design. Adopting a systems-oriented approach provides a comprehensive view, spanning from raw material acquisition to end-of-life product management. Such an approach not only identifies potential sustainability challenges but ensures that solutions foster both environmental responsibility and economic viability. In this study, a comprehensive framework for designing industrial systems is introduced, aiming to encompass the entire lifecycle impacts of chemical processes. The research initially delves into two …

Optimal Control Of Ion Exchange Process For Chromate Removal And Protein A Chromatography For Antibody Extraction, Fadi Ghanem

Theses and Dissertations

Ion exchange resins are widely used in the extraction of hazardous chemicals as well as the recovery of precious molecules. Therefore, an early breakthrough from the resin system can lead to toxic compounds affecting the drinking water quality or inefficient use of costly resins. Hence, accurate modeling of the ion exchange process and control strategy can enable decisions that assist in avoiding leakage when facing fluctuations in the inlet contaminant concentrations. In this work, the ion exchange process is modeled via the method of moments where the system uncertainties are captured via stochastic modeling using Ito processes. The flow rate …

Moisture Effects On Visible Near-Infrared And Mid-Infrared Soil Spectra And Strategies To Mitigate The Impact For Predictive Modeling, Francis Hettige Chamika Anuradha Silva

Theses and Dissertations

Instrumental disparities and soil moisture are two of the key limitations in implementing spectroscopic techniques in the field. This study sought to address these challenges through two objectives. The first objective was to assess Visible-near infrared (VisNIR) and mid-infrared (MIR) spectroscopic approaches and explore the feasibility of transferring calibration models between laboratory and portable spectrometers. The second objective addressed the challenge of soil moisture and its impact on spectra. The portable spectrometers demonstrated comparable performance to their laboratory-based counterparts in both regions. Spiking with extra-weight, was the most effective calibration transfer method eliminating disparities between instruments. The samples were rewetted …

Assessing The Thermodynamic Potential Of Deep Eutectic Solvents In The Absorption Of Greenhouse Gases Through Computational Methods, Thomas Michael Quaid

Theses and Dissertations

Greenhouse gas (GHG) capture is a fundamental technology in the fight against climate change. Some species of devastating GHGs like fluorinated compounds are released directly to the air from industrial processes. Some GHGs are co-produced in sustainably derived biofuels which require absorptive upgrading. The development of more efficient, cost effective, and environmentally friendly methods of capturing GHG’s from pollutant sources and industrial streams is of utmost importance in the fight against climate change. Deep eutectic solvents have entered the separations stage as potential disruptors to conventional solvent choices for a variety of applications. Deep eutectic solvents (DES) are compounds of …

Assessing The Thermodynamic Potential Of Deep Eutectic Solvents In The Absorption Of Greenhouse Gases Through Computational Methods., Thomas Michael Quaid

Theses and Dissertations

Greenhouse gas (GHG) capture is a fundamental technology in the fight against climate change. Some species of devastating GHGs like fluorinated compounds are released directly to the air from industrial processes. Some GHGs are co-produced in sustainably derived biofuels which require absorptive upgrading. The development of more efficient, cost effective, and environmentally friendly methods of capturing GHG’s from pollutant sources and industrial streams is of utmost importance in the fight against climate change. Deep eutectic solvents have entered the separations stage as potential disruptors to conventional solvent choices for a variety of applications. Deep eutectic solvents (DES) are compounds of …

Catalytic Hydrogenation Of Dimethyl Oxalate To Ethylene Glycol Using Silver Based Catalysts On Sba-15, Nicolas Edouard Gleason-Boure

Theses and Dissertations

Ethylene glycol (EG) is an important industrial chemical in the manufacturing of certain plastics. There is growing industrial interest in the production of dimethyl oxalate (DMO) from syngas, which can be hydrogenated to produce EG. Many studies have focused on the catalytic reduction of DMO using copper-based catalysts on silica supports, but fewer studies have been done on the effects of silver for this reaction. This work presents an in-depth study of silver catalysts prepared via various methods including incipient wetness impregnation, charge enhanced dry impregnation, and the use of various organic solvents. Reaction studies show that using pure methanol …

Heterogeneous Catalyst Design For Biomass Conversion, Dia Sahsah

Theses and Dissertations

Catalytic upgrading of bio-based feedstocks to commodity chemicals and fuels is pivotal to a more sustainable, renewable, and environmentally benign chemical economy. However, due to the high oxygen content, high water solubility, excessive reactivity, and thermal instability, typical and well-developed catalytic material and reactor processes reliably utilized in conventional petrochemical industry are, in general, not suitable for the processing of biomass feedstocks. Therefore, the development of novel heterogeneous catalysts is necessary in order to design new high-performance catalytic reactor systems. However, rational catalyst design is a multifaceted problem, and a myriad of factors influencing the catalytic performance at the reactor …

Structure Property Performance Of Ti3c2 Mxene/Polyelectrolyte Hybrids For Electronic And Electromagnetic Applications, Farivash Gholamirad

Theses and Dissertations

Hybrid materials based on transition metal carbide MXene (Ti3C2Tx) nanosheets have great potential for electronic, electromagnetic interference (EMI) shielding, and environmental applications due to the unique combination of considerable electrical conductivity of 4000 to 15000 S.cm-1, abundant surface functional groups (OH, O, F, Cl), and suitable mechanical properties. However, the performance of final products depends not only on the properties of constituent components but also on the morphology of the assembly. The strong repulsive electrical double layer forces among MXene nanosheets make control over their assembly morphology and final properties challenging. To address this challenge, this dissertation focuses on applying …

Insights Into Supported Metal Catalyst Sintering And Their Application For Bio-Oil And Crude Oil Upgradation, Md Fakhruddin Patwary

Theses and Dissertations

Typical heterogeneous catalysts consist of transition metal nanoparticles anchored against sintering on an inert, porous, high temperature stable support. The synthesis of supported catalyst involves pretreatment (drying, reduction) of deposited, ionic metal precursor complexes to form metal nanoparticles. In the first part of this work, we aim to understand the influence of pretreatment (reduction temperature, heating rate, moisture content) on final particle size. Supported nanoparticles of Pt and Pd were synthesized by strong electrostatic adsorption (SEA) and dry impregnation (DI). Reduced samples were characterized by in-situ and ex-situ XRD and STEM. The DI-derived samples generally showed an expected increase of …

Polybenzimidazole Membranes For Electrochemical Applications With Harsh Operating Conditions, Kris Likit-Anurak

Theses and Dissertations

Polybenzimidazole (PBI) membranes are high temperature proton exchange membranes (PEMs) which have advantages such as being able to operate in high temperatures, strong acid environments, and have no need for external humidity during operation. PBI membranes have been demonstrated to work effectively in multiple electrochemical devices, including fuel cells, hydrogen separation pumps, redox flow batteries, and a hybrid sulfur electrolyzer. In this work, para-PBI and densified para-PBI membrane have been used to improve electrochemical performance in harsh operating conditions that are both high temperature (≥120 ̊C) and high acid concentration (≥ 5M). First, we demonstrated the use of para-PBI membranes …

Understanding The Corrosion And Discharge Behaviour Of Zinc Anodes In Primary Alkaline Batteries, Brian James Lenhart

Theses and Dissertations

Primary zinc alkaline batteries power a wide array of everyday use electronic devices such as remote controls, calculators, cameras, and flashlights and will own an appreciable share of the battery market for the foreseeable future. Primary alkaline batteries generally utilize carbon, gas diffusion air, or manganese dioxide cathode but always coupled with a slurry zinc anode. There are several issues with this primary alkaline platform, largely emphasized by the performance of the zinc anode, such as a gassing phenomenon which leads to battery rupture and under certain circumstances, low material utilization leading to low energy density. The gassing and material …

Engineering Hybrid Colloidal Systems Formed By Charge-Driven Assembly Between Spherical Soft Nanoparticles And Discotic Nanoplatelets, Gelareh Rezvan

Theses and Dissertations

Soft matter, a fascinating class of materials, holds a paramount significance in the realm of material design and engineering. Within this broad category, colloidal gels with their unique characteristics have drawn tremendous attention in a variety of applications, spanning from biomedical engineering to oil and gas recovery. Meeting the specific requirements and criteria of these diverse fields necessitates the development of colloidal gels with highly tunable properties to optimize their performance for a wide range of applications. Hence, both scientific and industrial advancement call for more control over the gel properties by exploring novel practical parameters. This dissertation describes an …

Elucidating Self-Assembly Of Semiconducting Polymers In The Presence Of A Low Molecular Weight Gelator, Madhubhashini Lakdusinghe

Theses and Dissertations

Semiconducting polymers with a conjugated backbone are important for energy storage, conversion, and biomedical field applications. The self-assembly process of these polymers in solutions depends on the polymer concentration and quality of the solvent. The electrical properties of thin films obtained from the solution phase depend on the self-assembled process. Thin films of conjugated polymer gels with percolating networks of self-assembled structures display improved electrical conductivities. In this dissertation, we studied the impact of the secondary gel matrix formed by a low molecular weight gelator, on the self-assembly of conjugated polymers, the preservation of assembled structures in dried gel films …

Nanoscale Modeling Of Membrane Systems Under Mechanical Deformation In Traumatic Brain Injury Using Molecular Dynamics, Anh Thi Ngoc Vo

Theses and Dissertations

Neuronal membrane disruption and mechanoporation are nanoscale damage mechanisms that critically affect brain cell viability during traumatic brain injury (TBI). These nanoscale cellular impairments are elusive in experiments and necessitate in silico approaches such as molecular dynamics (MD) simulations. Implementing MD, this research aims to investigate the effects of different key factors related to membrane deformation and damage, including force field resolutions, lipid compositions, and loading conditions.

To examine the impact of force field resolution, MD deformation simulations were conducted on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC) lipid bilayer membranes, using all-atom (AA), united-atom (UA), and coarse-grained Martini (CG-M) force fields. The mechanical responses …

The Cosolvent And Association Effect On Polymer Behaviors, Xiangyu Zhang

Theses and Dissertations

The blending or mixing is extensively utilized in diverse processes of polymers to bring about advantageous properties, but the behavior becomes intriguing when associations are involved and multi-solvents are used. Explanations based on chemistry-specific arguments are less than satisfactory in abstracting essential features, and lack the general applicability across various systems. So, this work focuses on capturing the physical force governing the phenomenon of interest by using a generic model. Highly non-trivial behaviors of polymers are often observed in multi-solvent solutions. It is known that polymers swell and dissolve in good solvents, while they tend to collapse and aggregate in …

Designing Bioinspired Materials With Tunable Structures And Properties From Natural And Synthetic Polymers, Anandavalli Varadarajan

Theses and Dissertations

Biological systems are composed of complex materials which are responsible for performing various functions, such as providing structural support, mobility, functional adaptation to the environment, damage repair, and self-healing. These complex materials display excellent mechanical properties and can rapidly adapt to external stimuli. Thus, nature inspires in terms of source materials, functions, and designs to develop new-generation structural and functional materials. Polymers (natural or synthetic) are excellent sources of developing materials to mimic the functions of soft segments in biological systems. This dissertation focuses on synthesizing and characterizing two different materials with tunable structures and properties: complexes from natural polysaccharides …

Tuning The Metal/Acid Functionalities In Hzsm-5 For Efficient Dehydroaromatization, Genwei Chen

Theses and Dissertations

The increasing production of natural gas liquids attracts both academia and industry to develop on-purpose techniques converting those light alkanes to value-added chemicals. Dehydroaromatization is an alternative path for light alkane conversion to produce aromatics but still lacks active and stable catalysts. This work aims at the development of efficient dehydroaromatization catalysts by tuning the metal/acid bifunctionality of the Pt/HZSM-5 catalyst. Additionally, through co-processing light alkane with ammonia during the dehydroaromatization process, this study also proposes a new reaction system that could directly link the C-N bond for nitrile synthesis.

The results suggested that the activity, selectivity, and stability of …

Investigation Of Cyclic Gaseous Solvent Injection For Enhanced Oil Recovery In Unconventional Formations, Samuel Asante Afari

Theses and Dissertations

Unconventional resources have been known to hold vast quantities of hydrocarbons. However, exploiting the oil and gas they hold was previously challenging due to their low permeabilities. Recent advances in horizontal well drilling and hydraulic fracturing have enabled oil and gas production from these reservoirs, leading to significant increases in energy supply to meet the growing energy demand. However, despite the relative technological success, considerable obstacles persist; oil production from unconventional wells often declines by more than 20% of their initial production rate within the first two years, leaving significant volumes of residual oil trapped in the formations. This overarching …

Investigation Of The Performance Of Anti-Corrosive Coating Materials Derived From Bio-Based Feedstocks, Sarah Anne Salazar

Theses and Dissertations

Corrosion is a costly phenomenon that is largely responsible for the deterioration of various infrastructures. While there are many corrosion prevention techniques, polymeric coatings are the most cost-effective and frequently used methods for protection of metal surfaces. The most commonly employed polymeric coatings are non-renewable BPA-based epoxide resins. Common curing agents are also the derivatives of hazardous amines such as ethylene di-amine and methylene dianiline. Therefore, there is a growing demand to develop renewable and less-harmful precursors from biomass to replace rapidly depleting petrochemicals. This thesis focuses on the characterization and optimization of anti-corrosive polymeric coating formulations derived from renewable …

From Waste To Energy: The Electrochemical Reduction Of Co2 Using Recycled Nanostructured Catalysts, Ibrahim Badawy

Theses and Dissertations

The reduction of carbon dioxide (CO₂RR) using electrochemistry is a promising solution for the burgeoning global energy crisis. The overall vision of its implementation relies on renewable energy sources to power the reaction creating carbon neutral products and effectively closing the carbon cycle. Research in this field has come a long way since its inception in the mid-1900s. However, there remain significant hurdles and important considerations to overcome in order to reach full commercialization. Most electrocatalysts tested for CO₂RR have been designed solely for maximum performance while ignoring the environmental consequences if such a material were …