Chemical Engineering Commons^™

Impact Of Calendering And Silver Addition To Carbon Nanotube-Based Electrodes Used In Printed Multi-Layer Capacitors, Ramea Awni Al-Mubarak

Masters Theses

As the demand for global energy increases, the need for development of alternative clean and sustainable energy technology increases. Creating advanced energy devices with a large storage capacity plays a significant role in this development. This research focused on investigating the performance of capacitor devices used as energy storage cells by optimizing and determining the impact of silver percentage and structure (nano-wires or silver flake) added to CNT ink on the conductivity of printed layers, and studying the influence of calendering the multi-layer capacitor electrodes. Multi-layer capacitors were fabricated by screen printing three alternative layers of conductive and dielectric inks …

Low Melting Glass Frit As An Adhesion And Resistivity Promotor To Silver Nanoparticle Ink Photonically Sintered On Indium Tin Oxide Coated Glass, Jason J. Kleiner

Masters Theses

The objective of this study was the fabrication of a printed circuit resulting from the photonic drying/sintering of conductive circuits, printed using silver nano ink layered on a film of low melting glass frit onto indium tin oxide (ITO) coated glass substrate through the flexographic printing method. The fabrication process flow included material preparation, printing, and photonic drying/sintering in that order.

Investigation of the breakthrough photonic drying/sintering method was studied by varying sintering parameters, specifically the amount of heat energy applied to each specimen, and the speed at which it was applied. Additionally, the adhesion promoting properties of a never …

Bioactive Glass Reinforced Elastomer Composites For Skeletal Regeneration: A Review, Ehsan Zeimaran, Sara Pourshahrestani, Ivan Djordjevic, Belinda Pingguan-Murphy, Nahrizul Adib Kadri, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

Biodegradable elastomers have clinical applicability due to their biocompatibility, tunable degradation and elasticity. The addition of bioactive glasses to these elastomers can impart mechanical properties sufficient for hard tissue replacement. Hence, a composite with a biodegradable polymer matrix and a bio glass filler can offer a method of augmenting existing tissue. This article reviews the applications of such composites for skeletal augmentation.

Hydrocarbon-Based Fuel Cell Membranes: Sulfonated Crosslinked Poly(1,3-Cyclohexadiene) Membranes For High Temperature Polymer Electrolyte Fuel Cells, Suxiang Deng, Mohammad K. Hassan, Kenneth A. Mauritz, Jimmy W. Mays

Faculty Publications

High temperature fuel cell membranes based on poly(1,3-cyclohexadiene) were prepared by a Polymerization-Crosslinking-Sulfonation (PCS) approach, and a broad range of membrane compositions were achieved using various sulfonating reagents and reaction conditions. Membranes were characterized for their proton conductivity and thermal degradation behavior. Some of the membranes showed up to a 68% increase in proton conductivity as compared to Nafion under the same conditions (100% relative humidity and 120 °C). Thermogravimetric analysis revealed that these membranes are thermally stable up to 200 °C. High proton conductivity and thermal stability, combined with much lower cost as compared to Nafion®, make these materials …

Electrode Side Reactions, Capacity Loss And Mechanical Degradation In Lithium-Ion Batteries, Jiagang Xu, Rutooj D. Deshpande, Jie Pan, Yang-Tse Cheng, Vincent S. Battaglia

Chemical and Materials Engineering Faculty Publications

For advancing lithium-ion battery (LIB) technologies, a detailed understanding of battery degradation mechanisms is important. In this article, experimental observations are provided to elucidate the relation between side reactions, mechanical degradation, and capacity loss in LIBs. Graphite/Li(Ni_1/3Mn_1/3Co_1/3)O₂ cells of two very different initial anode/cathode capacity ratios (R, both R > 1) are assembled to investigate the electrochemical behavior. The initial charge capacity of the cathode is observed to be affected by the anode loading, indicating that the electrolyte reactions on the anode affect the electrolyte reactions on the cathode. Additionally, the rate of “marching” …

Economic And Sustainability Aspects Of Chemical Process Industries By Thermodynamics Analysis, Mahdi H. Alhajji

Department of Chemical and Biomolecular Engineering: Dissertations, Theses, and Student Research

Economics and sustainability improvements of some chemical processes are assessed after the retrofits suggested by thermodynamic analysis and energy analyzer. The main objective is to explore the scope of reducing the energy consumption and CO₂ emissions for a more sustainable operation in chemical process industries. Thermodynamic analysis is carried out by applying the thermal analysis capability of ‘Column Targeting Tool’ to address the ‘energy intensity,’ and/or the ‘Energy Analyzer’ to design and improve the performance of the heat exchanger network system for process heat integration. CTT is based on the ‘Practical Near-Minimum Thermodynamic Condition’ representing a close to practical …

A Quantitative Perspective On Surface Marker Selection For The Isolation Of Functional Tumor Cells, Calvin F. Cahall, Jacob L. Lilly, Edward A. Hirschowitz, Brad J. Berron

Chemical and Materials Engineering Faculty Publications

Much effort has gone into developing fluid biopsies of patient peripheral blood for the monitoring of metastatic cancers. One common approach is to isolate and analyze tumor cells in the peripheral blood. Widespread clinical implementation of this approach has been hindered by the current choice of targeting epithelial markers known to be highly variable in primary tumor sites. Here, we review current antigen-based tumor cell isolation strategies and offer biological context for commonly studied cancer surface markers. Expression levels of the most common markers are quantitated for three breast cancer and two non-small cell lung cancer (NSCLC) lineage models. These …

A Mathematical Model Of A Control Systems Hypothesis Of N-Methyl-D-Aspartate-Receptor-Mediated Ethanol Dependence And Withdrawal Dynamics, Carlos Gutierrez

Theses and Dissertations

The biochemical effects of ethanol on the human brain are manifested through many neurological pathways. Chronic exposure to the depressant has been shown to result in physical dependence. Subsequent cessation results in withdrawal symptoms such as seizures and both short- and long-term changes in neurological activity. One of the primary conduits implicated in the pathways of ethanol dependence and withdrawal is the detection of glutamate via N-methyl-D-aspartate (NMDA) receptors (NMDARs). Ethanol molecules inhibit these receptors, and consequent NMDA-induced glutamatergic changes can result in dependence on ethanol in order to sustain normal brain function. This study considers the relocation control of …

Matrix Compliance And The Regulation Of Cytokinesis, Savitha Sambandamoorthy, Shomita Mathew-Steiner, Scott Varney, Jonathan M. Zuidema, Ryan J. Gilbert, Livingston De Van Water, Susan E. Laflamme

Chemical and Biochemical Engineering Faculty Research & Creative Works

Integrin-mediated cell adhesion to the ECM regulates many physiological processes in part by controlling cell proliferation. It is well established that many normal cells require integrin-mediated adhesion to enter S phase of the cell cycle. Recent evidence indicates that integrins also regulate cytokinesis. Mechanical properties of the ECM can dictate entry into S phase; however, it is not known whether they also can affect the successful completion of cell division. To address this issue, we modulated substrate compliance using fibronectin-coated acrylamide-based hydrogels. Soft and hard substrates were generated with approximate elastic moduli of 1600 and 34,000 Pascals (Pa) respectively. Our …

The Role Of Environmental Dynamics In The Emergence Of Autocatalytic Networks, Joe Fusion

Dissertations and Theses

For life to arise from non-life, a metabolism must emerge and maintain itself, distinct from its environment. One line of research seeking to understand this emergence has focused on models of autocatalytic reaction networks (ARNs) and the conditions that allow them to approximate metabolic behavior. These models have identified reaction parameters from which a proto-metabolism might emerge given an adequate matter-energy flow through the system. This dissertation extends that research by answering the question: can dynamically structured interactions with the environment promote the emergence of ARNs? This question was inspired by theories that place the origin of life in contexts …

Optimum 3d Matrix Stiffness For Maintenance Of Cancer Stem Cells Is Dependent On Tissue Origin Of Cancer Cells, Esmaiel Jabbari, Samaneh K. Sarvestani, Leily Daneshian, Seyedsina Moeinzadeh

Faculty Publications

Introduction

The growth and expression of cancer stem cells (CSCs) depend on many factors in the tumor microenvironment. The objective of this work was to investigate the effect of cancer cells’ tissue origin on the optimum matrix stiffness for CSC growth and marker expression in a model polyethylene glycol diacrylate (PEGDA) hydrogel without the interference of other factors in the microenvironment.

Methods

Human MCF7 and MDA-MB-231 breast carcinoma, HCT116 colorectal and AGS gastric carcinoma, and U2OS osteosarcoma cells were used. The cells were encapsulated in PEGDA gels with compressive moduli in the 2-70 kPa range and optimized cell seeding density …

Secondary Organic Aerosol Formation From The Β-Pinene+No3 System: Effect Of Humidity And Peroxy Radical Fate, C. M. Boyd, J. Sanchez, L. Xu, Alexis J. Eugene, T. Nah, W. Y. Tuet, Marcelo I. Guzman, N. L. Ng

Chemistry Faculty Publications

The formation of secondary organic aerosol (SOA) from the oxidation of β-pinene via nitrate radicals is investigated in the Georgia Tech Environmental Chamber (GTEC) facility. Aerosol yields are determined for experiments performed under both dry (relative humidity (RH) < 2 %) and humid (RH = 50 % and RH = 70 %) conditions. To probe the effects of peroxy radical (RO₂) fate on aerosol formation, "RO₂ + NO₃ dominant" and "RO₂ + HO₂ dominant" experiments are performed. Gas-phase organic nitrate species (with molecular weights of 215, 229, 231, and 245 amu, which likely correspond to molecular formulas of C₁₀H₁₇NO₄, C₁₀H₁₅NO₅, C₁₀H₁₇NO …

Platinum-Bismuth Bimetallic Catalysts: Synthesis, Characterization And Applications, Jose A. Saucedo Jr, Yang Xiao, Arvind Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Bimetallic catalysts have been explored and shown to exhibit unique characteristics which are not present in monometallic catalysts. Platinum is well known as an effective catalyst for oxidation and reduction reactions, and it can be made more effective when bismuth is introduced as a promotor. Thus, the effectiveness of the Pt-Bi catalyst was demonstrated in prior work. What is not clear, however, is the mechanism behind the catalyst function; why addition of bismuth to platinum decreases deactivation and increases selectivity, and how effective would the Pt-Bi catalyst be in deoxygenation reactions? In this work, the effectiveness of different variations of …

Gold Nanoparticle Enhancements In Electroporation Mediated Dna And Rna Therapeutics, Shuyan Huang

Doctoral Dissertations

Nonviral gene delivery methods have been explored as the replacement of viral systems for their low toxicity and immunogenicity. However, they have yet to reach levels competitive to their viral counterparts. Electroporation figured prominently as an effective nonviral gene delivery approach for its balance on the transfection efficiency and cell viability, no restrictions of probe or cell type, and operation simplicity. The commercial electroporation systems have been widely adopted in the past two decades but still carry drawbacks associated with the high applied electric voltage, unsatisfied delivery efficiency, and/or low cell viability. What we did was to improve electroporation performance …

Swelling-Etching Characterization Of Copper (I) Oxide - Pdms For The Development Of Micro/Nano - Particles Composite Mems Corrosion Sensor, Abdoul Kader Maiga

Graduate Theses and Dissertations

The primary objective for this thesis is to contribute to the understanding of the oxide removal process for a corrosion sensing device. The goal for designing such a device is for monitoring corrosion on metallic structures. The sensing material (6.35mm x 1mm discs) of the device is composed of copper (I) oxide particles mixed in some polydimethylsiloxane (PDMS). The PDMS, “housing,” is meant for controlling the oxidation rate through the sensing material. A solvent was used to facilitate the etchant diffusion through the PDMS matrix. Toluene and acetic acid were the ideal solvent and etchant, respectively, for carrying out the …

Diamond Mems Biosensors: Development And Applications, Wenli Zhang

Doctoral Dissertations

This research focuses on the development a dielectrophoresis-enhanced microfluidic impedance biosensor (DEP-e-MIB) to enable fast response, real-time, label-free, and highly sensitive sensor for bacterial detection in clinical sample. The proposed design consists of application of dielectrophoresis (DEP) across a microfluidic channel to one of the impedance spectroscopy electrodes in order to improve the existent bacterial detection limits with impedance spectroscopy. In order to realize such a design, choice of electrode material with a wide electrochemical potential window for water is very important. Conventional electrode material, such as gold, are typically insulated for the application of DEP, and they fail when …

Model Of A Tubular Perfusion Bioreactor Using Computational Fluid Dynamics., Matthew James Robeson 1991-

Electronic Theses and Dissertations

Through recent years, many novel bioreactor designs for tissue engineering have emerged. The Tubular Perfusion System (TPS) is one such bioreactor for bone and cartilage tissue engineering. The TPS is a perfusion type bioreactor, in which media flows through a bed of scaffold beads. The advantage of this system over similar designs is that it requires no special fabrication techniques and operates at low pressure. Experimental trials have shown increased osteoblastic differentiation and mineralization of bone tissue grown using the TPS versus static culture. The effectiveness of the TPS in promoting osteoblastic differentiation is believed to be due to enhanced …

Hydrothermal Catalytic Liquefaction And Deoxygenation Of Biomass For Renewable Fuel Production, Sergiy Popov

Civil & Environmental Engineering Theses & Dissertations

In recent years, sub- and supercritical water technologies received an increasing attention because of the numerous advantages they offer for biomass converting into biofuels. Water at elevated temperatures and pressures provides an ideal medium for chemical transformations. It serves as a reactant, reaction medium, and catalyst that helps biomass compounds undergo hydrolysis, depolymerization, dehydration, decarboxylation, and condensation/repolymerization reactions. Biomass is the fourth largest source of energy in the world after coal, oil, and natural gas that has the potential to provide the large scale substitution of hydrocarbon-based liquid transportation fuels and minimize the environmental issues. Biomass typically contains 40-60% oxygen. …

Peptoid-Based Klvff Mimics: A Unique Approach To Alzheimer's Disease, James Phillip Turner

Graduate Theses and Dissertations

Alzheimer’s disease (AD) is the leading form of dementia worldwide. AD patients experience a slow, gradual cognitive decline that includes loss of memory and behavioral stability as the disease progresses. Surprisingly, AD is the sixth leading cause of death in the United States and has had a profound impact on the U.S. economy. Though there are medications to help improve the quality of life of diagnosed patients for a period of time, there is still no cure for AD. AD is characterized by the build-up of amyloid plaques that develop from the aggregation of the amyloid beta protein (Aβ) in …

Investigating The Impact Of Cryogenic Carbon Capture On Power Plant Performance, Seyed M. Safdarnejad, L. Kennington, Larry Lin Baxter, John Hedengren

Faculty Publications

Cryogenic Carbon Capture (CCC) is a CO2 mitigation process that can be integrated into existing baseline and load following fossil-fueled power plants. This process consumes less energy than conventional chemical absorption and includes energy storage capability. The CCC process has a fast response time to load changes to allow higher utilization of intermittent renewable power sources to be used at a grid-scale level in the power sector. The impact of the CCC process on the performance and operating profit of a single fossil-fueled power generation unit is studied in this paper. The proposed system (power production from wind, coal, and …

Using Peptoids To Build Robust, Efficient Microarray Systems, Dhaval Sunil Shah

Graduate Theses and Dissertations

Recent studies have shown microarrays to be indispensable for various biological applications, allowing for high-throughput processing and screening of biological samples such as RNA, DNA, proteins and peptides using a small sample volume (< 1 µL). Peptoids (poly-N-substituted glycine oligomers) can be used as a substitute for antibodies as capture molecules, as well as coatings for slides in antibody microarrays. The ease of synthesis of peptoids, high customizability with desired bioactivity, and speed of synthesis allows us to build a diagnostic system with a large dynamic range that can detect biomolecules from a minimal sample size. In this study, peptoid-based antibody mimics are designed to have both structural and functional features similar to those of antibodies, including a stable constant region (scaffolding) and a variable region for protein recognition. Peptoids previously screened via combinatorial library synthesis to be specific to bind Mdm-2 (mouse double minute 2 homolog) and GST (gluthathione S-transferase), have been synthesized. The protein recognition peptoids have been conjugated to PEG (polyethylene glycol) molecules with modified end groups; an amine group on one end that allows for immobilization and orientation on the slide, and an azide group on the other end that will allow for attachment to the peptoid through “click chemistry”. The number of capture molecules printed on the slides can be increased by making the available surface area of the slide larger via coating with microspheres. We have determined that partially water soluble peptoids that are also helical, can self-assemble into microspheres. Sequences have been developed that can consistently produce uniform microsphere coatings on slides that increase the overall surface area. A high surface area corresponds to a higher number of binding sites, and therefore a more sensitive system. The work done has shown that slides may be successfully coated in order to potentially improve the detection system.

A Computational Study Of The Potential For Lng Tanker Polystyrene Foam Insulation Failure Under Fire Exposure, Jeffrey David Martinez

Graduate Theses and Dissertations

Liquefied natural gas is shipped across the oceans in large marine carriers. The carriers house the LNG using several different insulation systems. One of these systems involves large aluminum spheres insulated with polystyrene foam. Polystyrene foam is very susceptible to heat degradation. This raised issues as to the extent of possible insulation failure caused by a large ship fire. Experiments were done investigating the nature of polystyrene’s thermal degradation, notably by Brauman, Chen, and Matzinger and Butler. A large scale investigation was also performed by Sandia National Laboratory. However, computational modeling of the degradation was lacking. This work set out …

Plant-Level Dynamic Optimization Of Cryogenic Carbon Capture With Conventional And Renewable Power Sources, Seyed M. Safdarnejad, John Hedengren, Larry Lin Baxter

Faculty Publications

Increasing competitiveness of renewable power sources due to tightening restrictions on CO₂ emission from fossil fuel combustion is expected to cause a shift in power generation systems of the future. This investigation considers the impact of the Cryogenic Carbon Capture™ (CCC) process on transitional power generation. The CCC process consumes less energy than chemical and physical absorption processes and has an energy storage capability that shifts the parasitic loss of the CCC process away from peak hours. The CCC process responds rapidly to the variation of electricity demand and has a time constant that is consistent with the intermittent …

Electromagnetic Induction By Ferrofluid In An Oscillating Heating Pipe, John Gabriel Monroe, Erick S. Vasquez, Zachary S. Aspin, Keisha B. Walters, Matthew J. Berg, Scott M. Thompson

Chemical and Materials Engineering Faculty Publications

No abstract provided.

Synthesis Of Graphene Wrapped Li-Rich Layered Metal Oxide And Its Electrochemical Performance, Meng-Yan Hou, Ke Wang, Xiao-Li Dong, Yong-Yao Xia

Journal of Electrochemistry

In present work, lithium-rich layered transition metal oxide (LLO) was synthesized by a co-precipitation method in combination with a solid-state reaction. The graphene wrapped Li-rich layered oxide composite (LLO/Gra) was obtained by sintering the LLO/GO composite at 300 ^oC for 30 min in an air. The morphologies and the electrochemical performances were characterized by means of SEM, TEM, XRD, XPS, EIS and charge/discharge tests. The results indicated that the LLOe particles were uniformly wrapped with graphene. The resulting material exhibited better rate capability than that of pristine LLO since the wrapped graphene demonstrated the enhanced electronic conductivity. Accordingly, the …

Enhancing Stability Of Pem Fuel Cell Catalysts Via Support Changing, Xiao-Hong Xie, Zi-Dong Wei

Journal of Electrochemistry

The Pt/C catalyst with highly dispersed Pt nanoparticles supported on carbon has been widely used as the state-of the-art catalyst in proton exchange membrane fuel cells (PEMFCs), while the durability of Pt/C is one of the major barriers for large-scale applications of PEMFCs. Thus, enhancing the stability of Pt/C has been a hot issue in this field. In this review, we summarize the recent progress in enhancing the catalyst stability in the view of support material. The future prospects of the PEMFCs catalyst should focus on adopting more stable supports or strengthening the interactions between Pt and supports.

Pt/C Modified Proton Exchange Membrane For Improved Fuel Cell Performance, Zhi Cui, Chao Wang, Shui-Yun Shen, Feng-Jing Jiang, Jun-Liang Zhang

Journal of Electrochemistry

The property of proton exchange membrane greatly affects the performance of proton exchange membrane fuel cells (PEMFC). During the operation of a PEMFC, the water produced at the cathode, the water vapor from the humidified feed gas and the water migrated by electro-dragging will reach a balance in the membrane and determine the resistance of PEMFC, and thus affect the performance of PEMFC. Normally, the PEMFC performance strongly depends on the relative humidity of the feed gas, and the performance decreases at lower humidity as a result of lower proton conductivity of the membrane. In this paper, we proposed to …

Sacrificial Amphiphiles: Eco-Friendly Chemical Herders As Oil Spill Mitigation Chemicals, Deeksha Gupta, Bivas Sarker, Keith Thadikaran, Vijay John, Charles Maldarelli, George John

Publications and Research

Crude oil spills are a major threat to marine biota and the environment. When light crude oil spills on water, it forms a thin layer that is difficult to clean by any methods of oil spill response. Under these circumstances, a special type of amphiphile termed as “chemical herder” is sprayed onto the water surrounding the spilled oil. The amphiphile forms a monomolecular layer on the water surface, reducing the air–sea surface tension and causing the oil slick to retract into a thick mass that can be burnt in situ. The current best-known chemical herders are chemically stable and nonbiodegradable, …

The Electroreduction Of Carbon Dioxide On Porous Copper Nanoparticles, Monica Alisa Padilla

Chemical and Biological Engineering ETDs

Copper nanoparticles of porous, controlled structure were synthesized using the sacrificial support method (SSM). The precursor weight percent (wt%) of copper (Cu) and fumed silica (EH-5) was varied to determine the optimum ratio for this material. The precursors were reduced at i) 350°C in a 7% H2 atmosphere and ii) at 250°C in a 100% H2 atmosphere. The specific surface areas of the nanoparticles was measured by Brunauer-Emmett-Teller N2 absorption. The morphologies and widths of the nanoparticles were confirmed by imaging the nanoparticles by scanning electron microscopy (SEM). The bulk composition of the nanoparticles was determined by X-ray diffraction (XRD). …

Analysis Of Particle Transport And Deposition Of Micron-Sized Particles In A 90° Bend Using A Two-Fluid Eulerian–Eulerian Approach, Erick S. Vasquez, Keisha B. Walters, D. Keith Walters

Chemical and Materials Engineering Faculty Publications

Two-phase flows involving dispersed particle and droplet phases are common in a variety of natural and industrial processes, such as aerosols, blood flow, emulsions, and gas-catalyst systems. For sufficiently dilute particle/aerosol phases, a simplified one-way coupling is often assumed, in which the continuous primary phase is unaffected by the presence of the dispersed secondary phase and standard CFD methods can be applied. To predict the transport and deposition of the particle phase, typically a Lagrangian particle-tracking or Eulerian one-fluid/two-phase drift-flux approach is used. Here, a full two-fluid Eulerian modeling approach is presented for coarse particles (>1 μm), in which …