Chemical Engineering Commons^™

Towards Rare-Earth-Free Permanent Magnets: Exchange Bias In Binary Mn-Based Alloys, Joshua Marion

Chemical Engineering Master's Theses

Quantum–mechanical exchange interactions between phases in ferromagnetic/antiferromagnetic (FM/AF) magnetic nanocomposite systems can result in useful effects such as exchange bias (H_ex) and remanence enhancement. These effects are more pronounced in nanostructured systems than in their coarse–grained counterparts due to improved interphase contact and can be developed to create good permanent magnetic behavior, but are currently poorly understood in bulk three–dimensional systems. To achieve this goal, factors such as the magnetic and structural phase identity, chemistry, size, shape, and character are investigated. To this end, synthesis, characterization and analysis of the magnetic and structural properties ...

Married Coal Gasification And Biomass Pyrolysis, Michael Balch

Honors Theses

This project is a proposal to marry a coal gasification process to a biomass pyrolysis. Coal is pyrolized to produce syngas and a large amount of heat. The syngas is treated and fed to a Fischer-Tropsch process. The excess heat produces steam that is used to pyrolize biomass. The biomass produces char, gas, and vapor. The char and gas are recovered, and the vapor is condensed to produce bio-oil.

The proposed plant has a capacity of 1100 tons of biomass (550 dry tons) per day. I assumed an operating factor of 0.9 The plant could be operational within five ...

Comparison Of Biomass To Bio-Oils Reactor Systems: Direct Conversion Vs. Companion Coal Gasification, Alexandra Eicher

Honors Theses

It is well known that the United States’ dependence on crude-oil negatively affects its economy, safety, and environment. To alleviate these negative consequences, a more economical and environmentally-friendly source of fuel, such as biomass, should be explored. The conversion of biomass to bio-oils involves the pyrolysis of biomass at about 500°C, thus requiring a great deal of heat. This heat source could be the excess waste heat from a coal gasifier.

As such, this report specifies the design of an industrial plant that produces bio-oils from biomass by using the waste heat from a coal gasifier. It is designed ...

Characterization Of Influenza Hemagglutinin Mutants For The Elucidation Of Key Residues’ Effect On Activation, Morgan Baltz

University of Tennessee Honors Thesis Projects

No abstract provided.

Advances In The Synthesis Of Zno Nanomaterials For Varistor Devices, Suresh Pillai, John M. Kelly, Raghavendra Ramesh, Declan Mccormack

Articles

ZnO based varistors are widely used for overvoltage protection in many electrical and electronic circuits, at voltages ranging from a few to over a million volts. By careful control of the microstructure, through nanostructuring by chemical routes, it should be possible to produce varistors with high breakdown voltage (Vc), as this is proportional to the number of active grain boundaries in the sintered body. This property is particularly important for the production of the small-sized varistors needed for modern electronic instruments such as tablet computers and mobile phones. The current review will outline the recent advances in the chemical processing ...

Economic Report On Vanadium Redox Flow Battery With Optimization Of Flow Rate, Kevin Spellman, Kendrick Stiles, Ian Little

University of Tennessee Honors Thesis Projects

No abstract provided.

Particle Fluidization In Upward And Inverse Liquid-Solid Circulating Fluidized Bed, Long Sang

University of Western Ontario - Electronic Thesis and Dissertation Repository

The fluidization of particles in upwards and inverse Liquid-Solid Circulating Fluidized Bed is carried out to investigate the hydrodynamic characteristics when using “heavy” and “light” particles, whose densities are higher and lower than that of the surrounding liquid respectively. Generally, the solids are fluidized upwards in the former case, whereas, the downwards fluidization is preferred in the latter scenario.

In the Liquid-Solid Circulating Fluidized Bed (LSCFB) riser, where the upwards fluidization takes place, the effects of particle properties on solids holdup are investigated experimentally based on three parameters: superficial liquid velocity, normalized superficial liquid velocity and excess superficial liquid velocity ...

A Novel Mixed Metallic Oxygen Carrier For Chemical Looping Combustion: Preparation, Characterization And Kinetic Modeling, Mohammad Rezwanul Quddus

University of Western Ontario - Electronic Thesis and Dissertation Repository

In last decades, significant concerns have been raised regarding the global warming effect. To date, about one-third of the total anthropogenic CO₂ emission results from power generation using fossil based fuel and CO₂ is the main contributor to global warming. Therefore, technologies for efficient capture of CO₂ are becoming of great value. In this respect, Chemical-Looping Combustion (CLC) has received significant attention as a promising technology facilitating concurrent CO₂ capture and power generation. This non-conventional technique employs a solid carrier, known as oxygen carrier, to supply oxygen and facilitates combustion process in absence of N_{2 ...}

Inventory Pinch Algorithms For Gasoline Blend Planning, Pedro A. Castillo Castillo

Open Access Dissertations and Theses

Current gasoline blend planning practice is to optimize blend plans via discrete-time multi-period NLP or MINLP models and schedule blends via interactive simulation. Solutions of multi-period models using discrete-time representation typically have different blend recipes for each time period. In this work, the concept of an inventory pinch point is introduced and used it to construct a new decomposition of the multi-period MINLP problems: at the top level nonlinear blending problems for periods delimited by the inventory pinch points are solved to optimize multi-grade blend recipes; at the lower level a fine grid multi-period MILP model that uses optimal recipes ...

Conference Program, Cedric Briens, Jesús Arauzo, Dietrich Meier

Bioenergy III: Present and New Perspectives on Biorefineries

No abstract provided.

Sol-Gel Derived Biodegradable And Bioactive Organic-Inorganic Hybrid Biomaterials For Bone Tissue Engineering, Bedilu A. Allo

University of Western Ontario - Electronic Thesis and Dissertation Repository

Treatments of bone injuries and defects have been largely centered on replacing the lost bone with tissues of allogeneic or xenogeneic sources as well as synthetic bone substitutes, which in all lead to limited degree of structural and functional recovery. As a result, tissue engineering has emerged as a viable technology to regenerate the structures and therefore recover the functions of bone tissue rather than replacement alone. Hence, the current strategies of bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix (ECM) as templates onto which cells attach, multiply, migrate and function.

In this ...

Predicting Enzyme Targets For Optimization Of Metabolic Networks Under Uncertainty, David Christopher Flowers

Masters Theses

Recently, ensemble modeling was applied to metabolic networks for the sake of predicting the effects of genetic manipulations on the observed phenotype of the system. The ensemble of models is generated from experimental wild-type flux data and screened using phenotypic data from gene overexpression and knockout experiments, leaving predictive models. The need for data from multiple genetic perturbation experiments is an inherent limitation to this approach. In this investigation, ensemble modeling is used alongside elementary mode analysis to attempt to predict those enzymatic perturbations that are most likely to result in an increase in a target yield and a target ...

Lignin Yield Maximization Of Lignocellulosic Biomass By Taguchi Robust Product Design Using Organosolv Fractionation, Anton Friedrich Astner

Masters Theses

Lignin, a byproduct of the organosolv pretreatment process using lignocellulosic biomass from switchgrass (Panicum virgatum) and tulip poplar (Liriodendron tulipifera) is currently being explored for its potential use in the production of value-added chemicals and biobased polymers. Pretreatment is one of the most expensive processing steps in cellulosic biomass conversion. Optimization of the process is one of the major goals of the biomass-toethanol conversion process. Taguchi Robust Product Design (TRPD) provides an effective engineering experimental design method for optimizing a system and designing products that are robust to process variations. Given the results of several preliminary studies of the organosolv ...

An Experimental Study On Thermal Stability Of Biodiesel Fuel, Yiying Zhu

Biomedical and Chemical Engineering – Theses

Biodiesel fuel, as renewable energy, has been used in conventional diesel engines in pure form or as biodiesel/diesel blends for many years. However, thermal stability of biodiesel and biodiesel/diesel blends has been minimally explored. Aimed to shorten this gap, thermal stability of biodiesel is investigated at high temperatures.

In this study, batch thermal stressing experiments of biodiesel fuel were performed in stainless steel coils at specific temperature and residence time range from 250 to 425 °C and 3 to 63 minutes, respectively.

Evidence of different pathways of biodiesel fuel degradation is demonstrated chromatographically. It was found that biodiesel ...

Particle-Collector Interactions In Nanoscale Heterogeneous Systems, Marina Bendersky

Open Access Dissertations

Particle-surface interactions govern a myriad of interface phenomena, that span from technological applications to naturally occurring biological processes.

In the present work, particle-collector DLVO interactions are computed with the grid-surface integration (GSI) technique, previously applied to the computation of particle colloidal interactions with anionic surfaces patterned with O(10 nm) cationic patches. The applicability of the GSI technique is extended to account for interactions with collectors covered with topographical and chemical nanoscale heterogeneity. Surface roughness is shown to have a significant role in the decrease of the energy barriers, in accordance with experimental deposition rates that are higher than those ...

Helical Ordering In Chiral Block Copolymers, Wei Zhao

Open Access Dissertations

The phase behavior of chiral block copolymers (BCPs*), namely, BCPs with at least one of the constituent block is formed by chiral monomers, is studied both experimentally and theoretically. Specifically, the formation of a unique morphology with helical sense, the H* phase, where the chiral block forms nanohelices hexagonally embedded in the matrix of achiral block, is investigated. Such unique morphology was first observed in the cast film of polystyrene-b-poly(L-lactide) (PS-b-PLLA) from a neutral solvent dichloromethane at room temperature with all the nanohelices being left-handed, which would switch to right-handed if the PLLA block changes ...

Novel Microwave Assisted Synthesis Of Zns Nanomaterials, Suresh Pillai, Michael Seery, Damian W. Synnott, John Colreavy, Stephen Hinder

Articles

A novel ambient pressure microwave-assisted technique is developed in which silver and indium modified ZnS is synthesised. The as prepared ZnS is characterised by X-ray diffraction, UV-Vis spectroscopy, X-ray photoelectron spectroscopy and luminescence spectroscopy. This procedure produced crystalline materials with particle sizes below 10 nm. The synthesis technique leads to defects in the crystal which induce mid energy levels in the band gap and lead to indoor light photocatalytic activity. Increasing the amount of silver causes a phase transition from cubic blende to hexagonal phase ZnS. In a comparative study, when the ZnS cubic blende is heated in a conventional ...

Synthesis Of Pdms-Metal Oxide Hybrid Nanocomposites Using An In Situ Sol-Gel Route, Qiaoyu Lu

Theses and Dissertations

Organic-inorganic hybrid nanocomposites are widely studied and applied in broad areas because of their ability to combine the flexibility, low density of the organic materials with the hardness, strength, thermal stability, good optical and electronic properties of the inorganic materials. Polydimethylsiloxane (PDMS) due to its excellent elasticity, transparency, and biocompatibility has been extensively employed as the organic host matrix for nanocomposites. For the inorganic component, titanium dioxide and barium titanate are broadly explored as they possess outstanding physical, optical and electronic properties.

In our experiment, PDMS-TiO₂ and PDMS-BaTiO₃ hybrid nanocomposites were fabricated based on in-situ sol-gel technique. By ...

Life Cycle Assessment Of Biofuels Produced By The New Integrated Hydropyrolysis-Hydroconversion (Ih2) Process, Edwin Maleche

Theses and Dissertations

Biofuels are alternative fuels that have the promise of reducing reliance on imported fossil fuels and decreasing emission of greenhouse gases from energy consumption. This thesis analyses the environmental impacts focusing on the greenhouse gas (GHG) emissions associated with the production and delivery of biofuel using the new Integrated Hydropyrolysis and Hydroconversion (IH²) process. The IH² process is an innovative process for the conversion of woody biomass into hydrocarbon liquid transportation fuels in the range of gasoline and diesel.

A cradle-to-grave life cycle assessment (LCA) was used to calculate the greenhouse gas emissions associated with diverse feedstocks production ...

Electrospun Chitosan Nanofibers For Virus Removal, Bingyu Bai

Theses and Dissertations

Electrospinning uses electrostatic forces to create nanofibers that are far smaller than conventional fiber spinning process. Nanofibers made with chitosan were created and techniques to control fibers diameter and were well developed. However, the adsorption of porcine parvovirus (PPV) was low. PPV is a small, nonenveloped virus that is difficult to remove due to its size, 18-26 nm in diameter, and its chemical stability. To improve virus adsorption, we functionalized the nanofibers with a quaternized amine, forming N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC). This was blended with additives to increase the ability to form HTCC nanofibers. The additives changed the ...