Engineering Commons^™

Nanomanufacturing Of Biomaterials, Yoni Engel, Jessica D. Schiffman, Julie M. Goddard, Vincent M. Rotello

Jessica D. Schiffman

In this review, we present a few of the many important objectives in the area of biomedical engineering that could open new pathways for nextgeneration biomaterials. We also provide examples of how materials for these goals can be created in an economically viable means through recent advances in high throughput production. These strategies highlight the potential for nanomanufacturing in a variety of areas of importance for human health and safety.

Genome-Based Modeling And Design Of Metabolic Interactions In Microbial Communities, Radhakrishnan Mahadevan, Michael A. Henson

Michael A Henson

Biotechnology research is traditionally focused on individual microbial strains that are perceived to have the necessary metabolic functions, or the capability to have these functions introduced, to achieve a particular task. For many important applications, the development of such omnipotent microbes is an extremely challenging if not impossible task. By contrast, nature employs a radically different strategy based on synergistic combinations of different microbial species that collectively achieve the desired task. These natural communities have evolved to exploit the native metabolic capabilities of each species and are highly adaptive to changes in their environments. However, microbial communities have proven difficult …

Macroscopic Patterning Via Dynamic Self-Assembly And Wrinkling Instability, Hyun Suk Kim

Open Access Dissertations

My PhD work focuses on developing new methods to create the macroscopic patterns in a simple, robust, and versatile way. For macroscopic pattern formation, we first use flow coating as an assembly technique, uniquely balancing two driving forces: (i) evaporative deposition of nonvolatile solutes at a three-phase contact line and (ii) precision movement of a confined meniscus layer. This balance leads to the formation of line-based patterns that range in height and width from nanometers to microns, with lengths greater than centimeters. Moreover, we couple this deposition methodology with functional ligand chemistry on the nanoparticle surface, which allows us to …

Porous Metal Oxide Materials Through Novel Fabrication Procedures, Nicholas Hendricks

Open Access Dissertations

Porous metal oxide materials, particularly those comprised of silica or titania, find use in many applications such as low-k dielectric materials for microelectronics as well as chemical sensors, micro/nanofluidic devices, and catalyst substrates. For this dissertation, the focus will be on the processing of porous metal oxide materials covering two subjects: hierarchical porosity exhibited over two discrete length scales and incorporation of functional nanomaterials. To generate the porous silica materials, the technique of supercritical carbon dioxide infusion (scCO2) processing was heavily relied upon. Briefly, the scCO2 infusion processing utilizes phase selective chemistries within a pre-organized amphiphilic block copolymer template using …

Modeling Material Transformations In Biorefinement, Vishal Agarwal

Open Access Dissertations

Lignocellulosic biomass is a significant pool of energy resource, which can be harnessed to supplement or replace the dwindling fossil fuel reserves. This requires development of economically viable means to efficiently convert biomass to biofuels. A major requirement in biofuel industry is to develop highly active, selective and stable catalysts. Zeolites are an important class of micro-porous crystalline solids, and have proven to be effective and stable acid catalysts for a variety of petrochemical and fine-chemical processes. Nitrided zeolites -- i.e., those with Si-O-Si and Si-OH-Al groups substituted by Si-NH-Si and Si-NH₂-Al -- have shown promise as shape-selective …

Interactions And Morphology Of Triblock Copolymer - Ionic Liquid Mixtures And Applications For Gel Polymer Electrolytes, Daniel F. Miranda

Open Access Dissertations

Room temperature ionic liquids (ILs) are a unique class of solvents which are characterized by non-volatility, non-flammability, electrochemical stability and high ionic conductivity. These properties are highly desirable for ion-conducting electrolytes, and much work has focused on realizing their application in practical devices. In addition, hydrophilic and ionophilic polymers are generally miscible with ILs. The miscibility of ILs with ion-coordinating polymers makes ILs effective plasticizers for gel polymer electrolytes. Due to their unique properties, ILs present a means to realize the next generation of energy storage technology. In this dissertation, the fundamental interactions between poly(ethylene oxide) (PEO) and a variety …

Risk Quantification Of Maple Trees Subjected To Wind Loading, Cihan Ciftci

Open Access Dissertations

Because of property damage and people injuries in, almost, every year in different locations of the earth, unfortunately the topic of understanding trees and their risk assessments under wind forces has not lost its importance since approximately a half of the last century. In contrast to loss its importance, the number of researchers or studies increases with time thanks to inter-disciplinary studies on that topic. In this Thesis, tree dynamics and their risk assessments subjected to wind forces were addressed by two different disciplines (civil engineering and environmental conservation).

To mention includes of this inter-disciplinary study, first, a finite element …

Modeling The Relaxation Dynamics Of Fluids In Nanoporous Materials, John R. Edison

Open Access Dissertations

Mesoporous materials are being widely used in the chemical industry in various environmentally friendly separation processes and as catalysts. Our research can be broadly described as an effort to understand the behavior of fluids confined in such materials. More specifically we try to understand the influence of state variables like temperature and pore variables like size, shape, connectivity and structural heterogeneity on both the dynamic and equilibrium behavior of confined fluids. The dynamic processes associated with the approach to equilibrium are largely unexplored. It is important to look into the dynamic behavior for two reasons. First, confined fluids experience enhanced …

Modeling The Self-Assembly Of Ordered Nanoporous Materials, Lin Jin

Open Access Dissertations

Porous materials have long been a research interest due to their practical importance in traditional chemical industries such as catalysis and separation processes. The successful synthesis of porous materials requires further understanding of the fundamental physics that govern the formation of these materials. In this thesis, we apply molecular modeling methods and develop novel models to study the formation mechanism of ordered porous materials. The improved understanding provides an opportunity to rational control pore size, pore shape, surface reactivity and may lead to new design of tailor-made materials. To attain detailed structural evolution of silicate materials, an atomistic model with …

Chemistry At Silicone - Inorganic Oxide Interfaces, Joseph W. Krumpfer

Open Access Dissertations

This dissertation describes research performed using siloxane polymers. This includes the reactions of siloxane polymers with inorganic oxide surfaces to form covalently attached monolayers, and the electrical properties of crosslinked silicone composite films fabricated by compounding with nickel particles. In addition to these topics, the use of contact line pinning as a practical and controllable method for the deposition of materials on superhydrophobic and chemically patterned surfaces is also described The first chapter provides a general review of siloxane polymer chemistry, focusing in particular on the relationship between molecular structure and physical properties. The use and fabrication of silicone composite …

Catalytic Fast Pyrolysis Of Furan Over Zsm-5 Catalysts: A Model Biomass Conversion Reaction, Yu-Ting Cheng

Open Access Dissertations

Due to its low cost and availability, lignocellulosic biomass is receiving significant attention worldwide as a feedstock for renewable liquid bio-fuels. We have recently shown that zeolites can be added to a pyrolysis reactor to directly make aromatics from solid biomass in one single step in a process called catalytic fast pyrolysis (CFP). The advantage of this approach is that valuable petrochemicals can be made directly from solid biomass in a single catalytic step using zeolite catalysts. However, little is known about the conversion chemistry that occurs within the zeolites during CFP. The objective of this thesis is to identify …

On The Effect Of Elasticity On Drag Reduction Due To Polymer Additives Using A Hybrid D.N.S. And Langevin Dynamics Approach, Arnout Boelens

Open Access Dissertations

In this work the effect of elasticity on turbulent drag reduction due to polymers is investigated using a hybrid Direct Numerical Simulation (D.N.S) and Langevin dynamics approach. Simulations are run at a friction Reynolds number of Re_&tau = 560 for 960.000 dumbbells with Deborah numbers of De = 0, De = 1, and De = 10. The conclusions are that it is possible to simulate a drag reduced flow using hybrid D.N.S. with Langevin dynamics, that polymers, like other occurrences of drag reduction, reduce drag through streak stabilization, and that the essential property of polymers and fibers in having a …

Production Of Green Aromatics And Olefins From Lignocellulosic Biomass By Catalytic Fast Pyrolysis: Chemistry, Catalysis, And Process Development, Jungho Jae

Open Access Dissertations

Diminishing petroleum resources combined with concerns about global warming and dependence on fossil fuels are leading our society to search for renewable sources of energy. In this respect, lignocellulosic biomass has a tremendous potential as a renewable energy source, once we develop the economical processes converting biomass into useful fuels and chemicals.

Catalytic fast pyrolysis (CFP) is a promising technology for production of gasoline range aromatics, including benzene, toluene, and xylenes (BTX), directly from raw solid biomass. In this single step process, solid biomass is fed into a catalytic reactor in which the biomass first thermally decomposes to form pyrolysis …

Systematic Synthesis Of Organic Semiconductors With Variable Band Gaps, Christopher Thomas Scilla

Open Access Dissertations

Polymeric materials are attractive candidates for the fabrication of low cost, large area photovoltaic devices. Controlling the band gap of the electroactive polymer is an essential factor in optimizing the resulting devices. In this dissertation, a methodology for the synthesis of well-defined semiconducting materials with tunable band gaps is described. First, the synthesis, characterization, and computational analysis of a variety of trimers consisting of two 3-hexylthiophene units flanking a central moiety consisting of thiophene, or one of the electron donating monomers isothianaphthene or thieno[3,4,b]thiophene will be described. From this analysis the influences of the electronic and steric structure of the …

Enhanced Mechanical Performance Of Low Dielectric Constant Thin Films Synthesized In Supercritical Co2, And Sans Studies Of Microemulsions Induced Or Destabilized By Compressed Co2, Alvin Horatio Romang

Open Access Dissertations

Block copolymer (BCP) phase segregation and self-assembly into two or more distinct domains are primarily dictated by two parameters: the block volume fraction, f, and the product of the segment-segment interaction parameter and the length of polymer chain, XN. The volume fraction determines a block copolymer's phase segregated morphology, whereas XN dictates its overall segregation strength, or phase stability. In order to achieve smaller domain sizes, the interaction parameter must be increased to compensate for the decrease in chain length. In the melt, PEO-b-PPO-b-PEO (Pluronic) triblock copolymer surfactants do not phase segregate primarily due to their low molecular weights …

Identification And Expression Analysis Of Methyl Jasmonate Responsive Ests In Paclitaxel Producing Taxus Cuspidata Suspension Culture Cells, Sangram K. Lenka, Nadia Boutaoui, Bibin Paulose, Kham Vongpaseuth, Jennifer Normanly, Susan C. Roberts, Elsbeth L. Walker

Susan C Roberts

Background Taxol(R)(paclitaxel) promotes microtubule assembly and stabilization and therefore is a potent chemotherapeutic agent against wide range of cancers. Methyl jasmonate (MJ) elicited Taxus cell cultures provide a sustainable option to meet the growing market demand for paclitaxel. Despite its increasing pharmaceutical importance, the molecular genetics of paclitaxel biosynthesis is not fully elucidated. This study focuses on identification of MJ responsive transcripts in cultured Taxus cells using PCR-based suppression subtractive hybridization (SSH) to identify genes involved in global pathway control. Results Six separate SSH cDNA libraries of paclitaxel-accumulating Taxus cuspidata P991 cell lines were constructed at three different post-elicitation time …

Kinetically Trapping Co-Continuous Morphologies In Polymer Blends And Composites, Le Li

Open Access Dissertations

Co-continuous structures generated from the phase separation of polymer blends present many opportunities for practical application. Due to the large interfacial area in such structures and the incompatibility between the components, such non-equilibrium structures tend to coarsen spontaneously into larger sizes and eventually form dispersed morphologies. Here, we utilize various strategies to kinetically stabilize the co-continuous structures in polymer blend systems at nano- to micro- size scales.

In the partially miscible blend of polystyrene and poly(vinyl methyl ether), we took advantage of the spinodal decomposition (SD) process upon thermal quenching, and arrested the co-continuous micro-structures by the addition of nanoparticles. …

Microtechnologies For Mimicking Tumor-Imposed Transport Limitations And Developing Targeted Cancer Therapies, Bhushan Jayant Toley

Open Access Dissertations

Intravenously delivered cancer drugs face transport limitations at the tumor site and cannot reach all parts of tumors at therapeutically effective concentrations. Transport limitations also prevent oxygen from distributing evenly in tumors resulting in hypoxia, which plays a critical role in cancer progression. In this dissertation, I present the development of micro-devices that mimic transport limitations of drugs and nutrients on three dimensional tumor tissues, enable visualization and quantification of the ensuing gradients, and enable simple analysis and mathematical modeling of obtained data. To measure the independent effects of oxygen gradients on tumor tissues, an oxygen delivery device that used …

Modeling The Free Energy Functional At The Fluid-Solid Transition In Classical Many-Particle Systems, Anurag Verma

Open Access Dissertations

The problem of phase equilibrium in colloidal and classical atomistic systems is of great interest in modern micro/nano fabrication and self-assembly processes. Systems with specific potential interactions are increasingly being developed and knowledge of their phase diagrams would aid in their use in materials applications. The conventional methods of using simulations and experiments to evaluate phase equilibrium are costly, especially for fluid-solid equilibrium. One way to address this problem is to improve the accuracy of theories, such as classical density functional theory (cDFT), that predict thermodynamic properties at the fluid-solid transition with modest computational cost. In such a program the …

A Population Balance Equation Model Of Aggregation Dynamics In Taxus Suspension Cell Cultures, Martin E. Kolewe, Susan C. Roberts, Michael A. Henson

Michael A Henson

The nature of plant cells to grow as multicellular aggregates in suspension culture has profound effects on bioprocess performance. Recent advances in the measurement of plant cell aggregate size allow for routine process monitoring of this property. We have exploited this capability to develop a conceptual model to describe changes in the aggregate size distribution that are observed over the course of a Taxus cell suspension batch culture. We utilized the population balance equation framework to describe plant cell aggregates as a particulate system, accounting for the relevant phenomenological processes underlying aggregation, such as growth and breakage. We compared model …

Catalytic Fast Pyrolysis Of Biomass In A Bubbling Fluidized Bed Reactor With Gallium Promoted Zsm-5 Catalyst, Jian Shi

Masters Theses 1911 - February 2014

The huge energy demand of our society is causing fossil fuel resources to diminish rapidly. Therefore, it is critical to search for alternative energy resources. Biomass is currently both abundant and inexpensive. Biofuels (fuels produced from biomass) have the potential to replace fossil fuels if a cost effective process can be develop to convert biomass into fuels.

Catalytic fast pyrolysis is a technology that can convert biomass into gasoline ranged aromatics in a single step. By heating biomass quickly to an intermediate temperature, biomass will thermally decompose into small molecules which can fit into zeolite catalyst pores. Inside the catalyst …

High Speed Flow Simulation In Fuel Injector Nozzles, Sukanta Rakshit

Masters Theses 1911 - February 2014

Atomization of fuel is essential in controlling combustion inside a direct injection engine. Controlling combustion helps in reducing emissions and boosting efficiency. Cavitation is one of the factors that significantly affect the nature of spray in a combustion chamber. Typical fuel injector nozzles are small and operate at a very high pressure, which limit the study of internal nozzle behavior. The time and length scales further limit the experimental study of a fuel injector nozzle. Simulating cavitation in a fuel injector will help in understanding the phenomenon and will assist in further development.

The construction of any simulation of cavitating …

Catalytic Fast Pyrolysis Of Wood And Alcohol Mixtures In A Fluidized Bed Reactor, George W. Huber, H. Zhang, T. R. Carlson, R. Xiao

George W. Huber

Catalytic fast pyrolysis (CFP) of pine wood, alcohols (methanol, 1-propanol, 1-butanol and 2-butanol) and their mixtures with ZSM-5 catalyst were conducted in a bubbling fluidized bed reactor. The effects of temperature and weight hourly space velocity (WHSV) on the product carbon yields and selectivities of CFP of pure pine wood and methanol were investigated. A maximum carbon yield of petrochemicals (aromatics + C2–C4 olefins + C5 compounds) from pine wood of 23.7% was obtained at a temperature of 600 °C and WHSV of 0.35 h−1. A maximum petrochemical yield from methanol of 80.7% was obtained at a temperature of 400 …

Production Of Renewable Aromatic Compounds By Catalytic Fast Pyrolysis Of Lignocellulosic Biomass With Bifunctional Ga/Zsm-5 Catalysts, George W. Huber, Y. Cheng, J. Jae, J. Shi, W. Fan

George W. Huber

Heiße Sache! Mit dem neuen difunktionellen Katalysator Ga/ZSM-5 entstehen aromatische Verbindungen bei der schnellen katalytischen Pyrolyse von Biomasse selektiver. Der ZSM-5-Katalysator mit Ga-Promotor wandelt Olefine wie Ethen und Propen, die als Intermediate entstehen, effizienter in Arene (insbesondere Benzol) um. Ga/ZSM-5 vermittelt auch Decarbonylierungen und die Aromatisierung von Olefinen.

Kinetics And Reaction Chemistryifor Slow Pyrolysis Of Enzymatic Hydrolysis Lignin And Organosolv Extracted Lignin Derived From Maplewood, George W. Huber, J. Cho, S. Chu, P. J. Dauenhaue

George W. Huber

The kinetics and reaction chemistry for the pyrolysis of Maplewood lignin were investigated using both a pyroprobe reactor and a thermogravimetric analyser mass spectrometry (TGA-MS). Lignin residue after enzymatic hydrolysis and organosolv lignin derived from Maplewood were used to measure the kinetic behaviours of lignin pyrolysis and to analyse pyrolysis product distributions. The enzymatic lignin residue pyrolyzed at lower temperature than that of organosolv lignin. The differential thermogravimetric (DTG) peaks for pyrolysis of the enzymatic residue were more similar to the DTG peaks for pyrolysis of the original Maplewood than DTG of the organosolv lignin. The condensable liquid volatile products …

Kinetics And Reaction Chemistry For Slow Pyrolysis Of Enzymatic Hydrolysis Lignin And Organosolv Extracted Lignin Derived From Maplewood, Paul J. Dauenhauer, J. Cho, S. Chu, G. W. Huber

Paul J. Dauenhauer

The kinetics and reaction chemistry for the pyrolysis of Maplewood lignin were investigated using both a pyroprobe reactor and a thermogravimetric analyser mass spectrometry (TGA-MS). Lignin residue after enzymatic hydrolysis and organosolv lignin derived from Maplewood were used to measure the kinetic behaviours of lignin pyrolysis and to analyse pyrolysis product distributions. The enzymatic lignin residue pyrolyzed at lower temperature than that of organosolv lignin. The differential thermogravimetric (DTG) peaks for pyrolysis of the enzymatic residue were more similar to the DTG peaks for pyrolysis of the original Maplewood than DTG of the organosolv lignin. The condensable liquid volatile products …

Revealing Pyrolysis Chemistry For Biofuels Production: Conversion Of Cellulose To Furans And Small Oxygenates, Paul J. Dauenhauer, M S. Mettler, S. H. Mushrif, A. D. Paulsen, D. G. Vlachos, A. D. Javadekar

Paul J. Dauenhauer

Biomass pyrolysis utilizes high temperatures to produce an economically renewable intermediate (pyrolysis oil) that can be integrated with the existing petroleum infrastructure to produce biofuels. The initial chemical reactions in pyrolysis convert solid biopolymers, such as cellulose (up to 60% of biomass), to a short-lived (less than 0.1 s) liquid phase, which subsequently reacts to produce volatile products. In this work, we develop a novel thin-film pyrolysis technique to overcome typical experimental limitations in biopolymer pyrolysis and identify α-cyclodextrin as an appropriate small-molecule surrogate of cellulose. Ab initio molecular dynamics simulations are performed with this surrogate to reveal the long-debated …

Identification Of Synthetic Host Defense Peptide Mimics That Exert Dual Antimicrobial And Anti-Inflammatory Activities, Nicolás Navasa, Abhigyan Som, Avital Percher, Richard W. Scott, Gregory N. Tew, Juan Anguita

Gregory N. Tew

A group of synthetic antimicrobial oligomers, inspired by naturally occurring antimicrobial peptides, were analyzed for the ability to modulate innate immune responses to Toll-like receptor (TLR) ligands. These synthetic mimics of antimicrobial peptides (SMAMPs) specifically reduced cytokine production in response to Staphylococcus aureus and the S. aureus component lipoteichoic acid (LTA), a TLR2 agonist. Anti-inflammatory SMAMPs prevented the induction of tumor necrosis factor (TNF), interleukin 6 (IL-6), and IL-10 in response to S. aureus or LTA, but no other TLR2 ligands. We show that these SMAMPs bind specifically to LTA in vitro and prevent its interaction with TLR2. Importantly, the …

Anion Mediated Activation Of Guanidine Rich Small Molecules, Abhigyan Som, Yongjiang Xu, Richard W. Scott, Gregory N. Tew

Gregory N. Tew

No abstract provided.