Haoxi Ben
Chemistry and Biochemistry
PSE Grad Student as of Jan 2009
Expected completion: Dec 2013
Graduate Research Assistant
haoxi.ben@ipst.gatech.edu

Resume

Haoxi Ben is a PhD student in the School of Chemistry and Biochemistry at Georgia Tech. His research focuses on converting biomass into biofuel by pyrolysis. Specifically, Haoxi's thesis research is pyrolysis of lignin. Lignin is the second most abundant biomass component and the only renewable aromatic resource in nature. Pyrolysis of lignin is a promising approach to upgrade this biopolymer. Haoxi has done some work about pyrolysis of softwood kraft lignin at different temperature, pyrolysis of lignin with additives and pyrolysis of different lignin. He will try to find some new additives to increase the yield and upgrade the properties of pyrolysis oil.

Emmanuel Doro
Mechanical Engineering
PSE Grad Student as of Aug 2007
Expected completion: May 2012
Graduate Research Assistant
edoro@gatech.edu

Resume

This study is designed to investigate in detail the flow physics and transport phenomena of falling liquid films using numerical simulation and experimental analysis. For both Newtonian (water) and non-Newtonian (black liquor) liquids, the study would analyse falling film flow phenomena such as: formation and evolution of capillary separation eddies (CSE), enhanced convective heat transfer in liquid film due to CSE, air entrainment due to interfacial wave interaction, and liquid film free surface wave breaking. In addition, the heat and mass transport associated with falling film free surface evaporation is investigated in detail. For falling films characterised by liquids with dissolved salts e.g. black liquor, the study also investigates how evaporation or salts enrichment  induce crystallization within the bulk flow.

Jessica Ewbank
Chemical and Biomolecular
     Engineering
PSE Grad Student as of Oct 2010
Expected completion: Sep 2014
Graduate Research Assistant
jle3@gatech.edu

Resume

My research focuses on tar reforming of biomass derived syngas. Syngas derived from biomass offers the chance to produce renewable, carbon neutral fuels. Tars are currently defined as condensable aromatics and are found in a much higher concentration in biogas than syngas derived from coal. Tar reforming is the bottleneck in utilization of biomass derived syngas. Tars can clog process lines, foul equipment, and hinder further processing of syngas. My work focuses on rational design of catalysts used for this application in order to successfully correlate catalytic activity with tar reforming capabilities. Tar reforming is being investigated under closely modeled syngas compositions and long on-stream studies are a major focus.

Timi Fadiran
Chemical and Biomolecular
     Engineering
PSE Grad Student as of Oct 2010
Expected completion: Sep 2014
Graduate Research Assistant
ofadiran3@gatech.edu

Resume

Directed assembly of cellulose and chitin nanofibers.

Hamilton Giles
Civil & Environmental Engineering
PSE Grad (minor) Student as of
     Aug 2007
Expected completion: Aug 2013
Graduate Research Assistant
hgiles3@gatech.edu

Resume

Sterols are naturally occurring compounds, based on the steroid four-ring structure, which contains a single hydroxyl group at the 3β position and a side chain at C17.  Sterols provide stiffness to the cell membrane of eukaryotes, while cholesterol serves as the precursor for sex steroid synthesis in animals. Phytosterols are released from wood fibers during the pulping process. Whole pulp-and-paper mill effluents, and sterols specifically, have been found to cause endocrine disruption in both aquatic and terrestrial organisms. Sterols have been shown to be degradable under aerobic and denitrifying conditions, but little is known about their degradation under anaerobic conditions. Pulp-and-paper wastewater contains significant concentrations of sulfate, and sulfate reduction has been observed in the sediment of the aerated stabilization basins (ASBs) commonly used by the pulp-and-paper industry. The phase distribution as well as the effect of alternating oxic/anoxic/anaerobic conditions on the fate of phytosterols in the ASBs and natural systems receiving treated pulp-and-paper effluents have not been evaluated sufficiently. The objectives of this research are to (1) investigate the phase distribution of phytosterols under conditions (i.e., pH, temperature, ionic strength) present in ASBs, (2) assess the biotransformation and degradation potential of sterols under variable redox conditions (i.e., aerobic to fully anaerobic), and (3) assess the effectiveness of different treatment conditions to remove the endocrine disrupting potential of pulp mill wastewater. The target sterols for this study are beta-sitosterol, stigmasterol, campesterol, and cholesterol. Sterol concentrations will be determined using liquid-liquid extraction of whole and filtered samples followed by GC-MS/FID. Systemic, controlled experiments utilizing mixed aerobic and anaerobic cultures developed from ASB mixed liquor and sediment, respectively, will be used in this study to assess the phase distribution as well as the biodegradation potential of the target sterols under conditions encountered in ASBs. The results of this research will aid in the design and operation of effective treatment systems for the removal of phytosterols and to predict their fate and effect upon release of treated pulp-and-paper effluent into natural receiving waters.

Lee Goetz
Chemistry & Biochemistry
PSE Grad Student as of Aug 2007
Expected completion: May 2012
Graduate Teaching Assistant
gtg071t@mail.gatech.edu

Resume

Lee Goetz is comparing the water absorption and retention and surface morphology of microwave and thermally initiated crosslinking of fully bleached kraft pulped hardwood and softwood pulp fibers with poly(methyl vinyl ether co maleic acid) – polyethylene glycol.  In addition, she is investigating in-situ crosslinking of cellulose nanowhiskers with the poly(methyl vinyl ether co maleic acid) – polyethylene glycol with the goal of improving cellulose whisker distribution through the matrix.

Lindsey Goodman
Materials Science & Engineering
PSE Grad Student as of Aug 2007
Graduate Research Assistant
lindsey.goodman@gatech.edu

Resume

Lindsey Goodman is a PhD student in the School of Materials Science and Engineering at Georgia Tech. Her research focuses on corrosion and environmentally assisted cracking of pipeline steel. Specifically, Lindsey's thesis research is geared toward studying the mechanism of stress corrosion cracking of pipeline steel in fuel grade ethanol environments. This topic is very pertinent in the alternative fuel industry, as there is a need for an efficient method of transporting these ethanol fuels throughout the country.  Stress corrosion cracking of carbon steels has become an expensive and difficult problem in the ethanol production plants, and if the phenomenological cause of this corrosion process is determined, cracking can be mitigated or prevented in oil and gas pipelines, making ethanol transportation safer and more efficient, via pipeline.

Stephani Gulbrandsen
Materials Science & Engineering
PSE Grad Student as of Aug 2007
Expected completion: Aug 2013
Graduate Research Assistant
stephani@gatech.edu

Resume

Stress corrosion cracking (SCC) of commonly used 316L stainless steel is known to occur in high temperature ethanolic environments. The purpose of this research is to understand how water content, temperature, chloride content, and solution pH affect the SCC of the material. Slow strain rate tests will be done to assess SCC susceptibility and electrochemical measurements will be taken to characterize the system. This research will help with understanding the mechanism of SCC in high temperature ethanolic solutions for 316L stainless steel.

Zack Heidemann
Mechanical Engineering
PSE Grad Student as of Jan 2008
Expected completion: Dec 2012
Graduate Research Assistant
zack.heidemann@gatech.edu

Somatic embryogenesis (SE) is widely considered to be the only feasible system to meet future needs for large scale production of elite plants for agricultural and forestry practices (Von Arnold and Clapham 2007). Somatic embryogenesis is the process by which somatic cells in the plant are removed and are coaxed into forming an embrogenic callus. From which the cells can be matured and regenerated into full plants (Von Arnold and Clapham 2007).  Efforts are underway to improve the laboratory protocols for proliferation and maturation of somatic embryos. Important contributions can be made by applying engineering solutions to facilitate growth and development of somatic embryos, and establish a platform for automation of the SE process.

For proper development into a plant, the somatic embryos require nutrients and growth regulators that are supplied by the culture medium.  The most efficient method for delivering these chemicals is via liquid suspension culture verses culture on gelled medium.   However, plant somatic embryos in vitro are adversely affected by the mechanical stress from the liquid suspension culture.  The rotating and deforming liquids destroy the polarity of multiplying somatic embryos that is required for successful embryo maturation (Sun et al. 2010).  Efficient scale-up of processes producing mature embryos in liquid culture bioreactors is thus not possible.

Aaron Howell
Mechanical Engineering
PSE Grad Student as of Sep 2011
Graduate Research Assistant
ahowell7@gatech.edu

Resume

Black liquor is a valuable source of energy in the paper mill. But, as it leaves the pulper, black liquor is not fit to be burned because its contains far too much water. The current solution is to condense the black liquor in a falling film or rising film evaporator. In either of these arrangements scale deposits on the heat transfer surfaces. The fouling of the surfaces reduces the effectiveness of the heat transfer requiring additional energy, and effort must be periodically taken to clean the evaporator surfaces.

This project seeks to determine a method for evaporating the black liquor as a suspended liquid, by applying hot air or superheated steam directly on the liquor. The elimination of the heat transfer surface removes the potential for scale formation and will allow the evaporator to operate in more consistent manner.

Fan Hu
Chemistry and Biochemistry
PSE Grad Student as of Jul 2008
Expected completion: Aug 2013
Graduate Research Assistant
fhu6@gatech.edu

It is generally accepted that incorporation of polysaccharide destruction products into lignin forms a lignin-like material termed pseudo-lignin during dilute acid pretreatment (DAP). My research has demonstrated that pseudo-lignin can be generated from cellulose and/or hemicellulose without significant contribution from lignin during DAP. My thesis contributes to said acquisition of knowledge by providing characterization of extracted pseudo-lignin from pretreated holocellulose and cellulose; proposing possible mechanisms of pseudo-lignin generation; and providing the reaction conditions (temperature, acid concentration and the presence of oxygen) associated with the mechanisms in order to diminish the amount of pseudo-lignin generation. More importantly, the formation of pseudo-lignin spherical droplets on the surface of pretreated carbohydrate reveals the possibility that those droplets may occlude pore structure and block enzyme accessibility or even bind to enzymes. Therefore, the study of pseudo-lignin-enzyme interaction will be significant for enzymatic deconstruction of cellulose and the determination of pretreatment conditions.

Alexander Jordan
Chemical and Biomolecular
     Engineering
PSE Student as of Aug 2010
Expected completion: Aug 2012
Graduate Research Assistant
atjordan@gatech.edu

Resume

A technology that can effectively separate ink from recycle mill effluent will significantly reduce the amount of water used in the recycling process of paper.  The ability of using only electrical energy is also a distinct advantage over other separation techniques as energy can be derived from many sources.  Submicron hydrophilic pigmented inkjet particles are very difficult to remove from the recycled fibers by using the traditional flotation deinking process.   If conditions are correct the particle sizes of the conglomerated organic compounds (ink) can be well above the micron scale and can be filtered out with ease.

Salil Joshi
Materials Science & Engineering
PSE Student as of Jan 2008
Graduate Research Assistant
salil.joshi.@gatech.edu

Resume

Indium Tin Oxide is widely used as a transparent conductor for optoelectronic applications. However, current deposition methods are unsuitable for fabricating inexpensive devices based on flexible and low-k substrates such as paper, PET, and cellulose based substrates. Using inks made from colloidal Indium Tin Oxide (ITO) is a potential route to fabricating transparent and conductive coatings on such substrates, by methods such as inkjet printing, microcontact fabrication, spin coating, etc. We have synthesized non-agglomerated ITO nanoparticles with a narrow size distribution. Although these can be fabricated into coatings, the challenges to be overcome when using this method is to be able to remove passivating organic coatings on the as-prepared ITO nanoparticles and to be able to densify the films at temperatures low enough to be used on non-heat resistant substrates. We have demonstrated that using appropriate plasma treatments can help achieve significant conductivity in spin-coated ITO films with only moderate heating. It is hoped that with further optimization of the processing and deposition techniques, it would be possible to fabricate transparent circuits with very minimal heating, and as a result facilitate the fabrication of ITO-conducting films, and other device circuits on paper and other heat sensitive and inexpensive substrates.

Yuzhi Kang
Chemical and Biomolecular
     Engineering
PSE Grad Student as of Aug 2009
Expected completion: Aug 2013
Graduate Research Assistant
ykang41@gatech.edu

Resume

Yuzhi Kang's area of research includes expression, characterization and protein engineering of cellulose binding domain and its biological functionality study for biofuel application. Her research would also include characterization of pretreated biomass.

Matyas Kosa      
Chemistry and Biochemistry
PSE Grad Student as of Aug 2007
Graduate Research Assistant
matyas.kosa@gatech.edu

The main focus of my work is lignin to lipid bioconversion by Rhodococci Gram-positive soil bacteria. Lignin sources include organosolv lignin from biomass pretreatment, Kraft-lignin from chemical pulping and LignoBoost lignin that is precipitated from black liquor by CO₂. Rhodococci have previously been reported to utilize lignin monomers as sole carbon sources, and later they were shown to be oleaginous, however, the two capabilities were never exploited simultaneously. Accordingly, I’m working on the adaptation and cultivation of selected strains on lignin, and optimization of fermentation conditions to maximize lipid production. These lipids are extracted and transesterified to fatty acid methyl esters for biodiesel –‘drop-in’ biofuel- utilizations.

Mikhail Levit
Chemistry and Biochemistry
PSE Grad Student as of Aug 2009
Expected completion: May 2014
Graduate Research Assistant
mikhail.levit@gatech.edu

Mikhail’s research focuses on kraft pulping of hardwoods with agricultural residue which leads to improvement of physical properties of bleached and unbleached pulps and paper. Studies employ different substitution levels of wood chips with Ag-resource and the investigation is directed at tracing the fate of hemicelluloses and cellulose during the process. Advanced characterization of lignin and testing of various properties of pulps and handsheets are performed.

Lester Li
Chemical and Biomolecular
     Engineering
PSE Grad Student as of Aug 2009
Expected completion: Aug 2013
Graduate Research Assistant
lesterl@gatech.edu

Resume

The understanding of the physical and chemical interactions between a surface and fluid have yielded the production of superhydrophobic and superoleophobic substrates. The goal of this proposal is to investigate and advance the control of fluid/surface interactions on plasma modified paper surfaces through the control of physical and chemical surface properties. This goal will be achieved through: fabrication and testing of substrates designed for microfluidic devices, and design and investigation of both physically and chemically-induced oleophobic surfaces on paper.

Stephanie Lin
Materials Science & Engineering
PSE Grad Student as of Jan 2011
Expected completion: Dec 2013
Graduate Research Assistant
stephanie.lin@gatech.edu

Resume

This research seeks to process and characterize cellulose-based nanocomposites to further explore the structure-property design space available in these materials. Specifically, the research will be structured to test the effect of high aspect ratio cellulose nanocrystals on the crystallization kinetics of the semicrystalline biopolymer matrix polyhydroxybutyrate (PHB), thus increasing the mechanical modulus and toughness concomitantly. If successful, this research will lead to the development of new materials with reduced environmental impact and unique combinations of properties that are unavailable in other materials. Additionally, the specific materials proposed will provide opportunities to increase the application range of PHB polymers and more fully describe the impact of the nanofiber aspect ratio on crystallization and mechanical properties. This fundamental understanding will provide insight into other types of polymer nanocomposites and provide guidelines for nanofiber composite design.

Jacob Lucrezi
Chemistry and Biochemistry
PSE Grad Student as of Jan 2010
Graduate Research Assistant
jlucrezi3@gatech.edu

Jacob Lucrezi is a PhD candidate in the School of Chemistry and Biochemistry at Georgia Tech. His research covers a range of topics from the effect of signaling molecules and redox potential on Loblolly Pine (LP) somatic embryo germination, drug delivery of a novel anti-inflammatory and investigation of inflammatory macrophage pathways. Loblolly Pine is the major source of timber in the US and is a valuable resource. Clonal propagation by somatic embryogenesis of LP embryos would allow a rapid reforestation of genetically superior high-value trees. Currently,  LP somatic embryos do not fully mature and fail to germinate. Zygotic LP embryos contain a seed storage organ, the female gametophyte (FG), which is not present in somatic embryos. A water extract of mid-stage FG stimulated LP somatic embryos to germinate fueling the hypothesis that the FG contains an active agent which promotes embryo germination. Through use of bioassays and many analytical methods the active agent in the FG is being identified. Similarly, the effect of redox potential on somatic embryo germination is also being investigated.

Tao Ma
Chemistry and Biochemistry
PSE Grad Student as of Jan 2012
Graduate Research Assistant
tao.ma@ipst.gatech.edu

Nazmul Huda Al Mamun
Mechanical Engineering
PSE Grad Student as of Aug 2006
Expected completion: May 2012
Graduate Research Assistant
nalmamun3@gatech.edu

Production of clonal propagules from selected superior genotypes has been playing a vital role in large scale production of high value plants for forestry, agricultural applications, biofuel production, ornamental purposes, or molecular pharming within the pharmaceutical sector. Among different techniques, somatic embryogenesis has shown potential in clonal propagation of many ornamental, medicinal, and agricultural plant species because of its advantages in terms of formation of matured embryos, embryo preservation, automation of the process, etc. However the implementation of somatic embryogenesis for large scale clonal propagation of plants and agricultural goods is affected by the non-synchronous development of somatic embryos. It can be assumed that the cells in a cluster of somatic embryos receive different levels of nutrients due to their location within the cluster, there by causes the asynchronous embryo development. Hence the focus of this research is to gain insight into the role of mechanical stress in synchronized development of somatic embryos in liquid culture medium. Our efforts are directed towards developing a technology based on mechanical stress delivered by fluid dynamics to disintegrate the clusters. This will help to provide a more predictable dispersion in favor of synchronization of embryo development.

Kendra Maxwell
Chemical & Biomolecular
     Engineering
PSE Grad Student as of Oct 2007
Expected completion: May 2012
Graduate Assistant
kmaxwell@gatech.edu

Resume

The breakdown of starch to sugars with amylase is the first step in the production of corn-based ethanol. We have found that the process is accelerated in the presence of cationic polymers. Kendra is studying the mechanism of the process with a view to reducing the cost of the enzyme.

Sarah McNew
Chemical & Biomolecular
     Engineering
PSE Grad Student as of May 2010
Expected completion: May 2014
Graduate Assistant
semcnew@gmail.com

Resume

My research focuses on understanding chemical engineering principles and reaction mechanisms to design catalysts upgrade pyrolyis oils by hydrodeoxygenation. These oils can be produced from any kind of organic feedstock including waste stream from the forest products and agricultural industry. However, many compounds in these mixtures are not stable enough to be transported and the resulting mixture contains chemicals that will impede direct use of the mixture as a fuel.  I am working on synthesizing sulfur-free heterogeneous catalysts to increase the stability and improve the quality of the bio-crude oil. The synthesis method and composition of the catalysts will be optimized based on characterization with a variety of physico-chemical techniques. Promising catalysts are tested on model compounds and the products are analyzed as the operating conditions of the reaction vary. These catalytic reactions are performed in a continuously operated fixed bed reactor.

Joseph Meyer
Materials Science & Engineering
PSE Grad Student as of Nov 2010
Expected completion: Nov 2012
Graduate Research Assistant
jmeyer32@gatech.edu

Molten salts act as solvents to the oxides that protect metals from corroding. With any solvent, there is a solubility limit that prevents further dissolution.
Solubilities will vary between oxides and it is possible to find an ideal oxide which would minimize the fluxing effects of the molten salt. Salts, like water, are combinations of acids and bases and the activities of the conjugate acids and bases can vary similarly to pH and pOH. By varying the pNa₂O of the salt, the solubility of the salt varies as well and the corrosivity of the salt can be controlled.

The project is useful because it could allow for an increase in the boiler temperature of the Kraft recovery boiler and thereby increase its efficiency. Biomass boilers like the Kraft recovery boiler are carbon neutral and will be more often used instead of fossil fuels. However, biomass boilers are less efficient than coal boilers since they are run at less than 500°C compared to nearly 600°C in their coal fired counterparts. This is all due to corrosion because the ash that accumulates on the superheater walls begins to melt and 500°C and drastically increases the corrosion rate. By reducing the solubility limit of the oxide in the molten salt, the corrosion rate can be decreased and the efficiency or lifetime of the boiler can be increased.

Sandeep Mora
Chemical & Biomolecular
     Engineering
PSE Grad Student as of Aug 2009
Expected completion: Aug 2013
Graduate Research Assistant
sxm3645@gatech.edu

Resume

It was recently shown by John Reye that cationic polymers can significantly accelerate both cellulose mediated hydrolysis of bleached paper fiber and the amylase catalyzed hydrolysis of cornstarch. Further studies will conducted to explore the effect of polymers on corn starch and cellulose hydrolysis. Different kinds of cationic polymers will be used in the current project and their mechanisms will be studied.

Wei Mu
Chemical & Biomolecular
     Engineering
PSE Grad Student as of Aug 2009
Expected completion: Aug 2013
Graduate Research Assistant
muw0@gatech.edu

Resume

My research focuses on understanding chemical engineering principles and reaction mechanisms to design catalysts to conversion any kind of organic feedstock into biofuel. Due to the complex composition of the biomass, the mechanism of the reaction is hard to describe. The catalyst will be optimized according to the reaction result. These catalytic reactions are performed in a autoclave batch reactor.

Gautami Newalkar
Chemical & Biomolecular
     Engineering
PhD Student as of Jan 2011
Expected completion: Dec 2013
Graduate Research Assistant
gnewalkar3@gatech.edu

Resume

The goal of my study is to investigate the gasification behavior of three different biomass candidates: loblolly pine, switchgrass, and corn stover. These three biomass species differ in their composition, particularly in the alkali content which plays a catalytic role in the gasification of char. The aim is to optimize gasifier design and conditions for syngas production from these feedstocks while minimizing tar and hydrocarbon contaminants in raw product gas. It is anticipated that the results from this work would provide a set of guidelines for other biomass candidates as well. The proposed work will provide a new option to produce value-added products from by-products in the paper and forest products industry, including branches, bark and forest residue.

Parisa Pooyan
Mechanical Engineering
PSE Grad Student as of Jan 2009
Expected completion: Dec 2012
Graduate Research Assistant
parisa.pooyan@gatech.edu

Resume

Designing a cellulose-based nanocomposite reinforced by crystalline nanowhiskers which create a three-dimensional percolating network and impart an excellent mechanical/ thermal stability to the entire structure at only 0.2 wt%. We believe this could not only expand the biomedical applications of cellulose but also could be a potential scaffold material in cardiovascular tissue engineering.

Michael Roy
Chemical and Biomolecular
     Engineering
PSE Grad Student as of Oct 2010
Expected completion: Sep 2014
Graduate Research Assistant
mikeroy@gatech.edu

Resume

My research will focus on the conversion of biomass, specifically lignin, into biofuels.

Amit Saxena
Chemistry & Biochemistry
PSE Grad Student as of Jan 2004
Graduate Teaching Assistant
gtg520t@mail.gatech.edu

Amit Saxena's project involves incorporation of nanocellulose whiskers in xylan to improve strength and barrier propoerties of composite films.

Sudhir Sharma
Chemical and Biomolecular
     Engineering
PSE Grad Student as of Jan 2012
Graduate Research Assistant
ssharma61@gatech.edu

Resume

My research is focused on the development of new green and biodegradable barrier materials based mainly on nanocellulosic fibers. These materials will be used as packaging for foodstuffs, pharmaceuticals, medical items and even dry good such as paper as well. The barriers will protect against water, oil and grease, oxygen and aroma. In some cases the barriers will also have excellent gas resistance.

Qining Sun
Chemistry and Biochemistry
PSE Grad Student as of Jan 2011
Expected completion: Dec 2014
qsun32@gatech.edu

Qining Sun's research project is about the analysis of chemical structures of celluloses and hemicelluloses, and focuses on the isolation and novel nanocomposite film prepared from Glucomannan.

Hongzhi Wang
Chemical and Biomolecular
     Engineering
PSE Grad Student as of Aug 2009
Expected completion: Aug 2013
Graduate Research Assistant
hwang97@gatech.edu

Resume

In a two-pronged approach, we investigate the fundamentals of emulsification with colloidal particles and apply the obtained insights to the design of emulsion-templated microcapsules with customizable properties for antimicrobial modification of paper and packaging materials. The fundamental part of the project focuses on understanding the prerequisites for decorating and stabilizing emulsion droplets with charged colloidal particles. Such particle-covered droplets are used, in the applied part of the project, as precursors for a new type of microcapsules suitable for efficient encapsulation of antimicrobial substances. The investigated capsules are designed to withstand the pressure, shear and thermal stresses encountered in papermaking and printing processes, while offering the benefit of sustained release or triggered release of their antimicrobial cargo in response to external stimuli such as pH, temperature, or, possibly, microbial attack. Specifically, the suitability of such microcapsules for the post-production functionalization of packaging surfaces by flexographic printing shall be explored.

Yushu Wang
Materials Science & Engineering
PSE Grad Student as of Oct 2011
Graduate Research Assistant
yswang@gatech.edu

Resume

Closed or partially closed chemical process system helps reduce fresh water usage as well as process water discharge in the pulp and paper industry. However, water properties change due to the recycling of process water, which promotes corrosion of existing equipment. Higher temperature, change in pH along with higher levels of residual chemicals, additives, and suspended solids all aggravates the corrosion. Different kinds of corrosion happen at the same time, such as pitting, stress corrosion, microbial corrosion, erosion-corrosion, etc. The purpose of this research is to understand the corrosion behavior of 304L, 316L and duplex stainless steels in white water system. The understanding of fundamental mechanisms of corrosion and stress corrosion cracking in white water system will lead to possible process optimization or facility improvement such as corrosion inhibitor or change of metal used in equipments.

Tyrone Wells
Chemistry & Biochemistry
PSE Grad Student as of Jan 2010
Expected completion: Dec 2013
Graduate Research Assistant
twells7@gatech.edu

Tyrone Wells is a PhD student and PSE fellow in the School of Chemistry and Biochemistry at Georgia Tech.  Due to their corrosive nature, pyrolysis oils provide complex containment difficulties to industry.  His work analyzes and optimizes the treatment of corrosive pyrolysis oils via microbial upgrading.  His goal is to generate less-corrosive, high-quality lipids using oleaginous microbes on pyrolyzed lignin.

Jie Wu
Polymer, Textile & Fiber Engineering
Materials Science & Engineering
PSE (minor) Grad Student as of
     Aug 2009
Expected completion: Aug 2013
Graduate Research Assistant
jwu71@gatech.edu

Paper and paperboard require significant whiteness and brightness so that printed images and text can achieve maximum optical contrast with faithful color reproduction. Traditional approaches to attain that goal have included lignin extraction, addition of mineral fillers and bleaching treatments that involve energy-intensive processes that produce additional waste streams and add additional mineral mass in the final product. A recent discovery indicates that a three-dimensional random network structure makes the white beetle have high whiteness and brightness. The project goal is to develop assembly methods for reproducing this white beetle scale structure synthetically and extend this approach to coat paper and paperboard products.

Brian Min Yun
Biomedical Engineering
PSE (minor) Grad Student as of Aug 2005
Expected completion: May 2012
Graduate Assistant
Min@gatech.edu

Resume

Prosthetic heart valves have been used for over 50 years to replace diseased native valves. The most widely implanted design is the bileaflet mechanical heart valve (BMHV) due to superior flow hemodynamics and blood damage performance. However, BMHVs still lead to severe complications such as hemolysis, platelet aggregation, and thromboembolic events. These problems have been linked to non-physiological shear stresses on blood elements. In order to reduce the severity of the complications and improve valve design, the blood damage that occurs in BMHV flows must be well understood. Computational fluid dynamics solvers can be used to model blood damage in pulsatile flows through BMHVs and ultimately improve valve design.

The numerical simulations of this study employ a fluid-solid coupling method that combines the lattice-Boltzmann Method (LBM) with the novel external boundary force (EBF) method. The LBM solution for fluid flow converges to the solution of the Navier-Stokes equations. In addition to being accurate, the LBM employs spatially local calculations due to roots in kinetic theory, making it optimal for parallel computing. The motion and orientation of suspended solid particles are captured solving the Newtonian dynamics equations. Fluid-solid coupling is computed using the EBF method by enforcing no-slip conditions on all solid surfaces. A linear shear stress-exposure time damage accumulation model can be used to quantify platelet damage.

Xiaodan Zhang
Polymer, Textile & Fiber Engineering
Materials Science & Engineering
PSE (minor) Grad Student as of
     Jan 2011
Expected completion: Dec 2013
Graduate Research Assistant
zxd200563008@gatech.edu

Resume

Nano thin films are made by layer-by-layer assembly of cellulose-based materials. Cellulose whiskers are prepared from wood pulp by hydrolysis and then modified with positive charge or negative charge. By dipping a substrate alternatively into positively charged and negatively charged cellulose materials, thin films are thus made through static electronic force.