graduate student research details_che
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DEPARTMENT OF CHEMICAL ENGINEERINGGRADUATE RESEARCH
SPRING 2009
Group Graduate Student & e-mail Title of ResearchFor more
details see page
Dr. Mahendra K. Sunkara, [email protected]
Room No.:
308/303c/306/307/201
Suresh Gubbala(Alumni)
“Nanowire Based Materials and Architectures for Electrochromicsand Dye Sensitized Solar Cells.”
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Theodore L. Druffel, [email protected]
“The engineering of optical devices from inorganic-organic nano-composites.”
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Jyothish Tangala, [email protected]
“Transformation studies of one-dimensional nanostructures.”
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Praveen Medhuri, [email protected]
“Hybrid Structure of Metal Oxide Nanowires Covered with Metal Nanoclusters for Stable, High-Capacity Li-ion Anodes.”
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Vivekanand Kumar, [email protected], [email protected]
“Bulk production of metal oxide nanowires (NWs) using a microwave plasma reactor.”
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Santhosh Rupa Dumpala, [email protected]
“Conical carbon nanotubular structures on large area flat substrates”
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Chandra Sekhar Pendyala, [email protected]
“Synthesis of III-V semiconductor nanowires and their band gap engineering towards photo electrochemical water splitting”
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Silpa [email protected]
“Inner surface modification studies in micro-capillary tubes by Micro-Plasma CVD inside the microreactor environment.”
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Boris [email protected]
“Photoelectrochemical Electrolysis Using Iron Oxide (a-Fe2O3) Nanowire Array Electrodes”
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Harry Ben [email protected], [email protected]
“Synthesis of tin and copper oxide nanowires as well as Titanium and Niobium foils”
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Dr. Gerold Willing
Room No.:
302, 204, 206A
Xioanting Hong,[email protected]
"Direct Force Measurement for the Silica Sphere-Plate System in Nanoparticle Suspensions by Colloidal Probe Technique"
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James Lee,[email protected]
“Bio-Imaging and Polymer Composites”
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Adam [email protected]
“RSV's impact on human cells by using an atomic force microscope to measure cell thickness and membrane elasticity over the course of the infection.”
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Kan Liu,[email protected]
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Sudheera [email protected]
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Dr. Berson
Room No.:
214
Samin [email protected]
“Saccharification of concentrated biomass slurries in a resonating acoustic mixer”
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Amlan [email protected]
“Computationally determined unsteady oscillatory fluid shear stress and its effects on endothelial cellular responses:”
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Kara [email protected]
“Studies to determine better corn hybrid to produce ethanol for whisky production process”
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Dr. Moises Carreon
Room No.:
207, 217
Surendar Reddy [email protected]
“Effect of Crystallization Growth Inhibitors in the Synthesis of SAPO-34”
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Chinmay [email protected]
“Nanoporous Gallium Oxides though Evaporation-Induced Self Assembly”
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Amruta [email protected]
“Synthesis and characterization of mesoporous Nanocrystalline titania and its application in the photocatalytic degradation of Methylene Blue and Methyl Orange”
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Dr. Kyung A Kang
312, 303 A,B,C.
Jianting Wang,[email protected]
“Application of nanometal particles in fluorophore mediated biosensing and bioimaging”
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Krishna Kanth [email protected],[email protected]
“Studies to optimize parameters (type of AEM generating probe, conc. of sample, time etc.) for heating nano magnetic particles”
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Others & Non-thesis
Zhuoliang [email protected]
“Studies on desorption of CBH1 from BMCC substrate as a function of enzymatic activity”
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Diana [email protected]
“Inorganic biochemistry --dirhodium anti-cancer complexes”
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Stewart [email protected]
“Studies on shelf life testing, particle size analysis, and product formulation in Food Processing Lab”
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Jackey [email protected]
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Name : Suresh GubbalaGroup & Lab : Dr. Sunkara Group, CVD lab e-mail : Alumni
Research Details:
“Nanowire based materials and Architectures for Electrochromics and Dye Sensitized Solar Cells”
The global energy demand is expected to triple by the end of the century. This demand of energy can be easily met with solar energy as the Sun provides more than 10,000 times this energy. In order to tap this energy, large area solar harvesting is required. For this to befeasible, the solar cells must have high efficiencies and low cost. One of the most promising technologies that can meet these demands is the dye sensitized solar cell. However, the dye sensitized solar cells currently in use are made of networks of nanoparticles, in which theelectron recombination with the electrolyte is high, leading to loss in efficiency and reliability.Nanowire based architectures provide unique advantages over nanoparticle and thin film based technologies due to their potentially better charge transport, recombination and electronic properties. Similar opportunities also exist in other devices such as Electrochromicsmart windows. The major challenges in these devices are the lack of sufficient contrast in the bleached and colored stated and long switching times on large area windows. In this work, nanowire based architectures for electrochromic and dye sensitized solar cells were investigated. In the case of electrochromics, the use of WO3 nanowires resulted in high contrast ratios (of ~0% to 70% transmission) between the colored and bleached states. The bleaching time in these devices was found to be slower than the coloration times. However, these timescales were faster than nanoparticle based devices. Similar results were also obtained with nanowires with mat like configuration. It was concluded that even higherperformance Electrochromic devices can be made by optimizing the nanowire density, diameters and aspect ratios. Nanowire based dye sensitized solar cells were demonstrated with SnO2 nanowires as the model system. Although all the previous work on SnO2nanoparticle based cells showed low open circuit voltages (Voc) of less than 400 mV, the use of SnO2 nanowires significantly improves the Voc of these devices to upto 560 mV. A variety of techniques were used to characterize these devices. Based on these studies, it was seen that nanowire based DSSCs showed faster electron transport, slower electron recombination kinetics, smaller work function and shallow average trap depths, all of which contributes to high Voc of these cells. These characteristics arise due to the high crystallinity of nanowirescompared to nanoparticles, which are highly polycrystalline. Further, the SnO2 nanowires were modified to engineer their band edges by coating them with TiO2 nanoparticles. Dye injected electrons from TiO2 quickly transfer into the SnO2 nanowires which then prevent anyrecombination reaction, thus improving the solar cell efficiency even further. SnO2 nanowires, due to their excellent properties and their ability to support other materials for band edge engineering, thus emerge as an excellent choice of material for dye sensitized solar cells. These nanowires can be incorporated into other DSSC anodes also, to further improve their
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performance. The possibility of the use of vertically oriented nanowires for DSSCs was also explored. He we show some preliminary results on Nb2O5 nanowire based DSSCs and the need to engineer the interface between nanowires and the substrate to improve their efficiency.
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Name : Theodore L. DruffelGroup & Lab : Dr. Sunkara Group, CVD lab e-mail : [email protected]
Research Details : “The engineering of optical devices from inorganic-organic nano composites.”
The assembly of extremely thin films of discrete refractive index and thickness find numerous applications in optical devices such as anti-reflective and mirror coatings. The history of these devices date to the early 20th century and the current state of the art includes vapor phase and sol-gel deposition of metal oxide thin films. The brittle ceramic films often fail in systems undergoing moderate strains. These coatings on plastic substrates are especially troublesome because of the strain mismatch and also due to the high processing temperatures. This dissertation presents a new approach to the deposition of thin film filters using inorganic-organic nanocomposites. The refractive index of the nanocomposite is manipulated by the volume of nanoparticles and these films can carry nearly 73 percent inorganic particles. Assembled nanocomposite thin film filters are shown in applications ranging from the ultra violet through the visible spectrum and into the infrared. These stacks range from assemblies of a few well engineered layers to nearly 40 discrete layers. Analysis of the thin film filters using spectroscopy and electron microscopes confirms that the nanocomposites behave as designed. Functionalization of the nanoparticles produces a homogeneous dispersion of the inorganic crystals within the film enhancing the optical and mechanical robustness. The elasticity of the nanocomposite is demonstrated by applying large strains never before possible for these optical devices.
The distinct refractive index boundary of the inorganic nanoparticles in the organic polymer can result in haze. The nanocomposites do perform as designed when assembled into thin film optical filters since the path lengths are short so scattering is minimized. Bulk materials will have path lengths several orders of magnitude longer and the particle size becomes a barrier to an optical article with low haze. The models suggest that true nanoparticle dispersions should result in low haze; however, these dispersions are difficult to attain. The knowledge gained through the research of thin film nanocomposites can be scaled to thicker sections. . .
Name : Jyothish Thangala
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Group & Lab : Dr. Sunkara Group, CVD lab e-mail : [email protected]
Brief about research :
I am currently working on phase transformation studies of one-dimensional nanostructures with primary interest in synthesizing different nitride compounds from the oxide materials. The goal is to primarily develop process chemistry for easy synthesis of nitrides, sulfides, and metal nanowires from oxide nanowires.
The other area of interest is developing process chemistries for synthesizing bulk quantities of oxides nanowires in the form of powders and also synthesizing nanowire arrays over large areas. The primary interest of bulk powders are in the area of composites and nanowire arrays in different photo electrochemical applications like electro chromic devices and hydrogen generation through water splitting.
Related Publications:
[1] J. Thangala, S. Vaddiraju, R. Bogale, R. Thurman, T. Powers, B. Deb, M. K. Sunkara, “Large-Scale, Hot-Filament-Assisted Synthesis of Tungsten Oxide and Related Transition Metal Oxide Nanowires”, SMALL, 3(5), 890, (2007)
[2] J. Thangala, Z. Q. Chen, A. H. Chin, C. Z. Ning and M. K. Sunkara, “ Phase Transformation Studies of Metal Oxide Nanowires”, Crystal Growth & Design (under review)
[3] S. Gubbala, J. Thangala and M. K. Sunkara, “Nanowire based Electrochromic Devices”, Solar Energy Materials and Solar Cells, 91( 9), 813, (2007)
Technical Skills :
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Name : Praveen MeduriGroup & Lab : Dr. Sunkara groupE-mail : [email protected]
Brief about research :
Nanowire-based systems show promise as Li-ion electrode material due to faster charge
transport, better conducting pathways and good strain relaxation. However, the stability of
nanowire based materials over cycling is either unknown or has been observed to fade
rapidly.
The basic design principle of this system involves that the metal oxide
nanowires are covered with metal nanoclusters with regular spacing
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larger than the diameter of each cluster. The spacing accomodates the volume expansion
during alloying, thereby preventing. agglomeration. The faster electron transport through the
underlying nanowires is expected to allow for efficient lithium alloying and dealloying, while the
exposed metal nanoclusters and metal oxide nanowire surfaces serve as lithium alloying sites.
Tin and tin oxide offer good semiconducting properties combined with high capacity (Sn, 994
mAhg-1 and SnO2, 781 mAhg-1) compared to that of graphite (372 mAhg-1). However, a
number of recent studies have shown significant capacity fading with these types of tin
systems.
Overall, the SnO2 nanowires covered with Sn nanoclusters exhibited a capacity of >800 mAhg-
1 over 100 cycles with a low capacity fading of less than 1% per cycle. Post lithiation analyses
after 100 cycles showed little structural degradation of the hybrid nanowires.
Related Publications :
Praveen Meduri, Chandrashekhar Pendyala, Vivekanand Kumar, Gamini U. Sumanasekera and Mahendra K. Sunkara (2009) Hybrid Tin Oxide Nanowires as Stable and High Capacity Anodes for Li-Ion Batteries.Nano Lett., Article ASAP doi: 10.1021/nl802864a.
Technical Skills :
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Name : Vivekanand KumarGroup & Lab : Chemical Vapor Deposition (CVD) lab, Dr. Sunkara groupE-mail : [email protected],
Brief about Research : Introduction: My research work focuses on the bulk production of metal oxide nanowires (NWs) using a microwave plasma reactor. NWs (typically less than 100 nm in diameter and few µm long ) are new class of nanostructures with applications in a variety of fields such as Li ion battery, dye sensitized solar cells (DSSC), catalysts, composites, gas sensing, electronics, and etc. For these entire applications bulk amount (Kg/day or in grams) of NWs are required and hence a method to produce them. However, current methods haven’t been able to produce NWs in bulk amount because they rely on use of a substrate which can limit the amount of materials produced.
We developed a novel method to produce NWs in gas phase directly, without any substrate. This allows us to produce different metal oxides NWs such as tin oxide, zinc oxide, alumina, titania in bulk amount. The nanowires are produced by pouring the micron sized metal powders of desired material (e.g. tin metal to produce tin oxide NWs) at the top of a microwave plasma reactor. A highly dense microwave plasma discharge, confined by a quartz
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tube, is generated using a microwave power source operating at 1.5kW and 2.45GHz. The gases such as O2, Air and H2 are supplied together at the top of the reactor. Metal powders are poured directly into the plasma cavity zone and then allowed to flow down by gravity with gas flow. As the metal powder falls through the plasma flame region it heats up, melts and reacts with the reactive species present in the plasma and solidifies quickly as it goes past the flame region and is collected in a cup in the form of powder. Kumar et al. poured different metal powder such as Sn, Zn, and Al under almost similar processing conditions to obtain respective metal oxide nanowires. The typical processing condition employed by them involved microwave plasma power of 1.5kW, micron size metal powders, 10 slpm of air, 100 sccm of H2, 500 sccm of O2. The plasma flame can process about 5 g/min of metal powder which translates to a production capacity of 5 kg of metal oxide NWs per day when operated continuously. Experiments performed at higher plasma powers, yielded spherical, unagglomerated metal oxide nanoparticles.
For detailed information, please see our recent publication. Please contact me if you have any questions or any ideas/suggestions.
Related Publication : Kumar, V.; Kim, J. H.; Pendyala, C.; Chernomordik, B.; Sunkara, M. K. “Gas-Phase, Bulk Production of Metal Oxide Nanowires and Nanoparticles Using a Microwave Plasma Jet Reactor”, J. Phys. Chem. C 2008, 112, 17750.
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Name : Santoshrupa DumpalaGroup & Lab : Dr. Sunkara’s research group (CVD Lab), EH 308A e-mail : [email protected]
Brief about Research :
We are working towards the synthesis of conical carbon nanotubular structures on large area flat substrates for studying various scientific and technological aspects. One of the challenges involved in the synthesis is studying the underlining mechanism and to be able to scale up to larger areas.
Technological Aspects: Applications of as synthesized conical carbon nanotubes on large area flat substrates include Field and thermionic emission, Electro-chemical sensing and Drug delivery patches.
Technical expertise : Scanning electron microscopy, Raman spectroscopy, X-ray diffraction spectroscopy, Electrochemistry.
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Name : Chandra Sekhar PendyalaGroup & Lab : Dr. Sunkara’s research group (CVD Lab), EH 308A e-mail : [email protected]
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“Synthesis of III-V semiconductor nanowires and their band gap engineering towards photo electrochemical water splitting”
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Name : Silpa KonaGroup & Lab : Dr. Sunkara’s research group (CVD Lab), EH 308A e-mail : [email protected]
“Inner surface modification studies in micro-capillary tubes by Micro-Plasma CVD inside the microreactor environment.”
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Name : Boris Chernomordik
Group&Lab : Dr. M. K. Sunkara, 308A/303c/306/307/201
E-Mail : [email protected]
Research Brief:
“Photoelectrochemical Electrolysis Using Iron Oxide (a-Fe2O3) Nanowire Array Electrodes”
The vision of this project is essentially the supply-side of the hydrogen economy. The idea is that you can use a photoactive semiconductor to split water. The hydrogen can then be stored and put through a fuel-cell when electricity is needed. Solar cells do not store energy and batteries have life-time and environmental issues. Photoelectrochemical electrolysis (solar hydrogen) is the cleanest method for producing hydrogen.
Fe2O3 is a promising material for water splitting reaction using solar energy due to its stability, optimal band gap of 2 eV, and abundance. We have several Fe2O3 nanowire synthesis methods, including oxidation in an atmospheric microwave plasma and thermal oxidation in a furnace. We are also collaborating with a group in Slovania, who can grow nanowire arrays using RF oxygen pasma. These nanowires are single crystal and have highly ordered oxygen vacancy planes. As one-dimensional nanostructures, these nanowires offer many other benefits to PEC electrolysis, such as high surface area, small minority carrier diffusion distance, a direct and unhindered route for majority carrier diffusion to the back contact, and high crystallinity. Furthermore, due to the ordered-oxygen vacancy planes in these nanowires, the resistivity that has plagued this material may become a non-issue.
Preliminary investigation has demonstrated significant photoactivity and we are developing techniques to improve performance both on pre- and post-synthesis, such as doping/alloying.
Some Related Publications:
1. Bak, T.; Nowotny, J.; Rekas, M.; Sorrell, C. C. Intl. J. of Hydrogen Energy 2002, 27, 991-1022.
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2. Hardee, K. L.; Bard, A. J. J. of the Electrochem. Soc., 1976, 123, 1024-1026.
3, Kennedy, J. H.; Anderman, M. J. of the Electrochem. Soc., 1983, 130, 848-852.
4. Lindgren, T.; Wang, H. L.; Beermann, N.; Vayssieres, L.; Hagfeldt, A.; Lindquist, S. E. Solar Energy Mater. and Solar Cells 2002, 71, 231-243.
5. Ingler, W. B.; Khan, S. U. M. Electrochem. and Solid State Lett., 2006, 9, G144-G146.
6. Cvelbar, U.; Chen, Z.; Sunkara, M. K.; Mozetic, M. Small 2008, In press.
7. Chen, Z.; Cvelbar, U.; Mozetic, M.; He, J.; Sunkara, M. K. Chem. of Mater., 2008, 20, 3224-3228.
8. Kennedy, J. H.; Frese, K. W. J. of the Electrochem. Soc., 1978, 125, 723-726.
Technical Expertise: SEM, Raman, (Photo) Electrochemistry, MW/HF CVD Reactors, XRD, UV-Vis, EDS, Kelvin Probe
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Name: Harry "Ben" RussellGroup & Lab : Dr. Sunkara's CVD Groupe-mail : [email protected], [email protected]
Brief about research: “Synthesis of tin and copper oxide nanowires as well as Titanium and Niobium foils.”
Related Publications : noneTechnical expertise: (eqpt. handled / can handle) HF CVD and Plasma reactors, SEM. .
Dr. Gerold Willing’s Group:
Name: Xioanting HongGroup & Lab : Dr. Willing’s Groupe-mail : [email protected]
Research Details : "Direct Force Measurement for the Silica Sphere-Plate System in Nanoparticle Suspensions by Colloidal Probe Technique"
Colloid stabilization is presently a subject of intense experimental and theoretical interest with many researchers focusing on charge stabilization and steric stabilization mechanisms. In recent years, the novel colloid stabilization mechanism of Nanoparticle Haloing has become a promising research trend. However, researchers have not explored the stabilization mechanism experimentally from the surface interaction perspective. The development of atomic force microscopy (AFM) has made it possible to directly measure the surface interaction forces between two colloidal particles in a solution. Prior to direct force measurements, we developed MATLAB programs for the simulation of the DLVO interaction
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forces theoretically. Additionally we developed a cantilever calibration method by fitting the experimental force curves to the theoretical force curves based on DLVO theory for the silicamicrosphere and silica flat interaction in a dilute KBr and HNO3 solutions in order to measure the interaction forces accurately. Upon finishing a cantilever*s calibration, we began to explore the colloid stabilization mechanism of nano-particle haloing where negligibly chargedsilica microspheres can be stabilized by the addition of highly charged nano-particles under an acidic environment near the iso-electric point of the microsphere. The transition force curves between the silica sphere and the silica flat-plate in different ZrO2 nanoparticle suspensions was firstly investigated and the transition from attractive to repulsive interactions can be untilized to explicitly show the nano-particle haloing stabilization. Subsequently, an effective zeta potential fitting model was proposed to demonstrate the contribution of different forcesincluding the van der Waals force, effective electrostatic force and depletion force to the mechanism. Finally, we expanded the surface force measurements to other nanoparticle suspensions. The size ratio of the nano-particle to the sphere is extensively discussed. Ultimately, the surface forces measured by colloidal probe technique can be used to predict the stabilization properties of the mixtures of nano-particles and microspheres in an effort to directly engineer new complex fluid systems.. .
Name: James Lee
Group & Lab: Dr. Gerold Willing’s Advanced Materials and Nanotechnology Group, 206A
e-mail: [email protected]
Brief Research Description: “Bio-Imaging and Polymer Composites”
Bio-Imaging: Proteins, cells, and other biological specimens are imaged using the AFM. The elasticity and force measurements on these samples are also determined using contact methods.
Polymer Composites: Biocompatible polymers, such as hydrogels, are being developed with metallic nano particles and polymers with specific mechanical characteristics to form a polymer composite with unique functions. The formation of these polymer composites are studied at the nano level for controlled and purposeful construction. The formation of the polymer composites have equal contribution to its characteristic and function as the polymer components.
Related Publications: No publications at this time
Technical Expertise: AFM, Optical Contact Angle Goniometer.
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Name: Adam Pfendt Group & Lab: BioImaging Group Lab 204 (Dr. Willing)email: [email protected] about Research: “RSV's impact on human cells by using an atomic force microscope
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to measure cell thickness and membrane elasticity over the course of the infection.”Publications: pendingTechnical Expertise: AFM. .
Name: Kan LiuGroup & Lab: BioImaging Group Lab 206A (Dr. Willing)email: [email protected]
Brief about Research:
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Name: Sudhira PasupuletiGroup & Lab: BioImaging Group Lab 204 (Dr. Willing)email: [email protected]
Brief about Research:
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Dr. Berson’s Group:
Name : Samin RezaniaGroup & Lab : Dr. Berson’s research group
e-mail : [email protected]
Research Details :
“Saccharification of concentrated biomass slurries in a resonating acoustic mixer” Biomass is converted to ethanol as the result of several processing steps of which enzymatic hydrolysis (saccharification) is a key rate and cost limiting step. It is desirable to begin with a high solids concentration in order to maximize the product concentration in the sugar stream, minimize water and energy use, and minimize reactor volume. However, when processing with concentrated slurries, the high viscosity leads to lower glucose release rates and yields. It is hypothesized that this is due to mass transfer limitations, specifically (1) inefficient contact between the enzyme and substrate, and (2) inefficient movement of product away from the reaction sites. Both of these effects can hinder glucose release from the cellulose.
In the first part of this study, ultrasonic irradiation was employed to reduce the particle size of untreated sawdust slurries to less than 1 *m in an attempt to increase the enzymatic saccharification rate by increasing surface area for contact between the enzyme and
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substrate, and to lower the slurry viscosity. Results showed that ultrasonic irradiation was effective in reducing the particle size of pretreated corn stover an untreated sawdust solids in terms of both particle size distribution and average particle size of the substrate. Surprisingly, the amount and rates of sugar released in this study with ~1 *m particles was comparable to, but no better than that seen for particle sizes in the range of 33 * x * 75 *m. Also surprisingly, the viscosity increased as the average particle sizes in the slurries decreased, which is opposite to the trend seen in a previous study at higher size ranges. This was attributed to the variations in surface characteristics of the particles which were characterized here using X-ray diffraction profiles and SEM pictures.
In the second part, a study was conducted to determine if overcoming mass transfer limitations in pretreated corn stover slurries can increase saccharification rates at high solids concentrations. In order to achieve good dispersion of the liquid enzyme throughout highviscosity biomass slurries, a resonating acoustic mixer was employed for running saccharification tests with initial solids concentrations of 15 to 30%. Results showed that the mixer achieved higher glucose release rates and yields than in shake flasks, especially at higher viscosities. For 15% initial solids, the yield was just 4% higher, but for 30% initial solids the yield was 40% higher.
In the last part, dispersion coefficients in the mixing vessel were determined as a function of viscosity in order to quantify the mass transfer improvements. Since conventional means of measuring dispersion could not be performed with these types of slurries, a computationalfluid dynamics model was developed that simulated motion of the slurries in the resonating acoustic mixer. The model was very well validated by comparing experimentally determined mixing times using an electrolytic tracer with mixing times from the simulations. Simulated mixing times were within 2% of experimental mixing times. Results showed that axialdispersion coefficients were higher than radial ones, with bigger differences at lower viscosities. For a viscosity of 20 cP, the axial coefficient was approximately 6.5 times higher than the radial coefficient, while at a viscosity of 25,000 cP, the axial coefficient was just approximately 3 times higher than the radial coefficient. As the viscosity increased from 20 to 25,000 cP, the axial and radial dispersion coefficients decreased approximately by 89% and 77% respectively. Despite the very high viscosities studied here, dispersion values were still achieved on the order of values in other systems designed for much thinner fluids, which indicates the system was a valid choice for studying mass transfer limitations.
Related Publications :
Technical Expertise :
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Name : Amlan ChakrabortyGroup & Lab : Dr. Berson’s research group, Baxter II - 132 e-mail : [email protected]
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Research Details :
“Computationally determined unsteady oscillatory fluid shear stress and its effects on endothelial cellular responses:”
Introduction:The effects of hemodynamic forces on cellular responses have been studied since last three decades. Wall shear stresses (WSS) are commonly accepted as the primary influence affecting the anchored cells subjected to fluid flow. More importantly shear has some important effects on the development of disease like atherosclerosis which is initiated by a dysfunctional state of the vascular endothelium. Background:It is important to measure the shear accurately in laboratory. Parallel plate flow chamber, cone and plate apparatus and orbital shakers are commonly used equipment. Due to some important limitations of parallel plate flow chamber and cone and plate apparatus, orbital shaker is widely accepted nowadays in cell culture industry. The system involves endothelial cell cultures grown in a petri dish oscillating on a shaker platform. But since generated shear in orbital shaker is not uniform and oscillatory in nature, it is hard to determine the magnitude of shear analytically. Though researchers made attempt to measure the shear analytically, it is not accurate to estimate average oscillatory shear value over entire bottom of the dish.
Brief description about the work:To overcome all of those limitations, Computational Fluid Dynamics (CFD) is nowadays applied to measure wall shear stress (WSS) in orbiting dishes on shaker apparatuses. Though it is required to model the fluid motion properly, due to difficulty of quantifying, the fluid motion inside the dish has not been modeled yet accurately. Therefore the effects of four dimensionless parameters (Stokes Number, Slope Ratio, Froude Number, and Reynolds Number), which govern the fluid motion inside the dish, will be analyzed in the first part of this study. Transition points for above four parameters will be derived and analyzed to study the fluid behavior. Oscillated shear exerted by fluid motion on the cultured cells are then quantified by incorporating CFD at different locations at the bottom of the dish. It has been observed that depending on the locations, oscillating shear values are different. Near the center of the dish, the shear values are minimized whereas near the edge of the dish, shear values are maximized. For instance, at higher orbital speed (210 rpm), the shear zone near the edge is at the range of 0-13 dyne/cm2 whereas the range near the center is about 0-3 dyne/cm2). Effects of the oscillated shear stress on cultured endothelial cells will therefore be investigated. Cell proliferation and morphological changes of shear exposed cells will be compared with normal cells at different specific locations of the dish and exerted shear will be quantified by CFD. It is shown in preliminary results that cells behave in different ways at different locations under varying levels of shear zones. As reported in preliminary results, it is evident that cell proliferation decreases near the periphery of the dish at higher shear exposure whereas it increases notably near the center of the dish at lower shear exposure. But cell morphological shapes will be increased with increase of shear values. Also effect of
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frequency of oscillation and magnitude of applied shear on the cells will be investigated. Since fluidic shear has important impact on the disease like atherosclerosis and the role of Leukotriene B4 and their receptors (BLT1) are implicated in disease like atherosclerosis, the current proposal will determine the effects of shear stress in presence of LTB4
and LPS on HUVEC cells at different locations under varying orbital speeds. Since the effect of shear stress on BLT1 regulation in endothelial cells is completely unknown, the expression patterns of BLT1 in HUVECs under shear stress will be determined. The role of LPS should also be investigated in the expression of BLT1 in cells that are exposed to shear stress.
Technical expertise :CFD software: fluent, gambit.Cell culture technique: flow cytometry, cell culture, apoptosis detection method.. . .
Name : Kara ZoellerGroup & Lab : Dr. Berson (ex-group)e-mail : [email protected]
Brief about research :
“Studies to determine better corn hybrid to produce ethanol for whisky production process”
In the whisky industry there is a balance between the desire to adhere to the traditional production process and the desire for increased profit margins. One solution that follows both stipulations is to increase the alcohol yield of a given batch of whisky. This can be achieved by utilizing high total fermentable (HTF) corn rather than non-HTF corn. HTF corn has a higher concentration of fermentable starches than non-HTF corn, leading to the potential for a greater final ethanol yield. By simply using a higher quality of raw materials, the integrity of the process is maintained while allowing an increase in output.
Ten strains of HTF corn (35D28, 35Y33, 34M94, 32K33, 34P88, 33A84, 34H31, 31G66, 33N56, and 34A15) and four strains of control corn (33N09, 32W86, 33M54, and 34D71) were tested for pH, sugar content by mass (balling), conversion of starch to sugar, conversion of sugar to ethanol, and alcohol content by volume (ABV). Ten trials were performed using HTF corn, yielding 60 fermentations; 18 trials were performed using control corn, yielding 158 fermentations. Due to contamination from an unknown source, only 44 HTF and 41 control fermentations were clean and, therefore, were used to establish the most significant trends.For a 99% confidence level, a clean HTF fermentation yielded 9.69% * 0.14% ABV and a clean control fermentation yielded 9.34% * 0.08% ABV. From these values it was determined that the HTF corn provides a 3.7% increase in alcohol yield over control corn. This clearly indicates that the HTF corn provides a significant advantage over the control corn, especially
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when moved to an industrial scale. When the contaminated fermentations were analyzed it was found that the contaminated HTF fermentations yielded 9.28% * 0.11% ABV and the contaminated control fermentations yielded 9.04% * 0.08% ABV. Therefore, the contaminatedfermentations showed a 2.7% alcohol yield increase for HTF corn over control corn. While this correlation is not as strong due to being compromised by contamination, it is still plainly indicative of the advantage HTF corn has in relation to non-HTF corn.
When the strains are compared on an individual basis, the HTF strain 32K22 appears to be the premium candidate for whisky production at this preliminary stage. It demonstrated the highest levels of conversion of both starch and sugar, at 97.6% and 98.3% respectively, aswell as producing the highest alcohol content of any strain at 10.42% ABV. The 32K22 strain achieved an overall conversion of starch to ethanol of 95.9% which is significantly higher than the average overall conversion for the control corn, 88.5%.
I'm not currently doing any research. I've completed my thesis and the research for that was done at Brown-Forman while on co-op. It dealt with determining which type of corn hybrid produces the most ethanol when used in the whisky production process.
Relate Publications: none
Technical expertise: jacketed cookers, distillation columns, water baths, hammer mill.
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Dr. Carreon’s Group :
Name : Surendar Reddy VennaGroup & Lab : Dr. Carreon’s research group, EH 207 e-mail : [email protected]
Brief about Research :
“Effectof Crystallization Growth Inhibitors in the Synthesis of SAPO-34”
Dr. Carreon's group is working on synthesis of functional materials like zeolites and mesoporous metal oxides for gas separation and catalysis applications.
Introduction: Carbon dioxide is a significant impurity in many natural gas wells. The CO2
must be removed in order to utilize the natural gas; CO2 reduces the energy content of the gas, and it is acidic and corrosive in the presence of water. SAPO-34 is one of the best material to separate CO2 from natural gas. Since the pore size of SAPO-34 is nearly equal to the kinetic diameter of CO2. Also, SAPO-34 has been successfully employed to separate carbon dioxide and hydrogen from different gases. SAPO-34 has been used for the trapping of hydrocarbons, in particular, for cold start emission control in the automobile industry. In petrochemical industry, many treatment methods are involved with catalyst, in particular zeolites. SAPO-34 has been using in petrochemical industry to process different gases
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depending on their molecular size. Properties such as fairly strong Brønsted acidity, adsorption of desired components, and excellent shape selectivity make SAPO-34 an ideal active and selective catalyst in methanol-to-olefin reaction and hydrocarbon transformation. In addition, due to its unique cage size and shape, SAPO-34 has been found to be suitable for selective formation of lower olefins from methanol.
Synthesis: SAPO-34, a particular type of zeolite, is synthesized using different methods like hydrothermal treatment, microwave treatment and dry-gel conversion method with the use of templates like tetraethylammonium hydroxide, dipropylamine, triethylamine, morpholine and piperidine. In each method with different templates, SAPO-34 is formed with different properties. So by carefully selecting the method, synthesis parameters and synthesis gel composition, SAPO-34 with specific properties and for specific application can be synthesized.
Applications: The synthesized SAPO-34 is used to prepare membranes on alumina support. These membranes are used to separate the CO2/CH4 gases, which is the main application in natural gas. But the same membranes also used to separate different gases like hydrogen, nitrogen and other olefins. The SAPO-34 also been used as catalyst for methanol to olefin reactions, chloromethane transformations, conversion of heavier organics to lighter organics.
Related Publications :
Venna, S.R., Carreon, M.A., J. Phys. Chem. B, 2008, 112(51), 16261-16265
Moises A. Carreon, Shiguang Li, John L. Falconer, and Richard D. Noble, J. AM. CHEM. SOC. 2008, 130, 5412–5413
Technical expertise :BET porosimeter, Scanning Electron Microscopy, Gas chromatography
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Name : Chinmay DeshmaneGroup & Lab : Dr. Carreon’s research group, EH 207 e-mail : [email protected]
Research Details :
“Nanoporous Gallium Oxides through Evaporation-Induced Self Assembly”
Mesostructured metal oxides are not only useful as catalysts and separating or adsorbing agents but also as functional host materials with unique optical, electrical magnetic properties, owing to the shape-specific and/or quantum effects of their thin inorganic skeletons. In particular, gallium oxide is a wide-band-gap semiconductor (Eg = 4.9 eV) that exhibits luminescence and conduction properties with potential applications in optoelectronic devices, high temperature stable gas sensors and high-temperature/high-power electronic devices. Also, it has been used as a catalyst for the oxidative dehydrogenation of ethane to ethene and propane to propene. My research involves synthesis of nanoporous Gallium Oxides through Evaporation-induced self assembly.
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Research Publications :
Technical Skills :
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Name : Amruta KattiGroup & Lab : Dr. Moises Carreon’s research group, EH 207 e-mail : [email protected]
Brief about Research :
Currently we are working on the synthesis and characterization of mesoporous Nanocrystalline titania and its application in the photocatalytic degradation of Methylene Blue and Methyl Orange.
Titania so far is the most ideal photocatalyst for the destruction of common organic pollutants such as dyes in the solid, liquid and vapor phases. Mesoporous titania has gained a lot of attention because of its high surface area, uniform mesopore size and shape and a nanocrystalline frame work.
Related Publications :
“Pore architecture affects photocatalytic activity of mesoporous nanocrystalline anatase thin films.” Moises A.Carreon, Sung Yeun Choi, Marc Mamak, Naveen Chopra and Geoffrey A. Ozin. J. Mater. Chem, (2007, 17, 82-89)
Fundamentals of mesostructuring through Evaporation Induced Self- Assembly. D. Grosso et al. Adv. Funct. Mater. (2004, 14)
Technical expertise : SEM, XRD, BET, UV- VIS Spectroscopy, Raman Spectroscopy, FTIR.. .
Dr. Kang’s Group :
Name: Jianting WangGroup@Lab: Dr. Kang’s group, Biosensing/imaging labEmail: [email protected] about research:My research effort has been on application of nanometal particles in fluorophore mediated biosensing and bioimaging. For fluorophore mediated biosensing and bioimaging, artificial alteration of fluorescence (enhancement/quenching) can be highly beneficial for improving sensitivity and contrast. Certain type of nanoparticles, including nanogold particles (NGPs), can increase or decrease the fluorescence of fluorophores by their strong surface plasmon polariton field. We have been utilizing NGPs to enhance the sensitivity of our fluorophore mediated biosensing system. Combining both fluorescence quenching and enhancement
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properties by NGP, we are creating a novel optical contrast agent for molecular imaging. This agent is specially designed to be conditionally emitting fluorescence only at the disease site, with a high specificity and high contrast.
Related publications:
J. Wang, M. Nantz, S. Achilefu, K. A. Kang. FRET-like fluorophore-nanoparticle complex for highly specific cancer localization, Proceeding of the 36th ISOTT annual meeting, Aug. 4-7, Sapporo, Japan, accepted
J. Wang, B. Hong, J. Kai, J. Han, Z. Zou, C. H. Ahn, and K. A. Kang. Mini sensing chip for Point-of-Care AMI diagnosis utilizing MEMS and nano-technology, Proceeding of the 35th ISOTT annual meeting, Aug. 26-29, Uppsala, Sweden
Technical expertise:
(1) Biosensor/ diagnostic device- Fiber-optics- MEMS based, multi-analyte, microfluidic, point-of-care, immuno-sensing device
(2) Plasmonics and biophotonics- Metallic nanoparticle fluorescence enhancer
(3) Nanoparticle/colloid- Synthesis, surface treatment and functionalization of metallic nanoparticles- Synthesis of fluorescent, cancer specific, therapeutics functionalized magnetic
nanoparticles- Particle size analysis / SEM / TEM
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Name : Krishna Kanth SanapalaGroup & Lab : Dr. Kang’s research group, EH 303A/303B/3030C e-mail : [email protected], [email protected]
Brief about Research :
“Studies to optimize parameters (type of AEM generating probe, conc. of sample, time etc.,) for heating nano-magnetic particles”
Dr. Kang's group is working in collaboration with science & medical school researchers to design / develop a nano entity that can be used for both detection and treatment of cancer.
Detection : Recent advances include use of nano-gold particles (for its light scattering properties) to target cancer sites for easy detection. When gold nano particles (GNP) coated with EGFR-antibodies are injected into humans, particles cling to the tumor site and scatters incident light in all directions making the malignant cells distinct from the normal cells. It was also found that by placing a florophore (a florescence causing particle) at a specific distance (optimum) from GNP would enhance the scattering light intensity upto 10 folds. Research work is going on to find optimum distance, different spacers to link GNP to florophore.
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Treatment : It is in practice that we use GNP for detection & magnetic nano particles for treatment of cancer cells. Efforts are on to use Fe3O4 coated GNP (both gold & iron oxide are bio-compatible) so that it can serve for both detection and treatment. I am now working on Alternating Electromagnetic (AEM) field generating unit to optimize the following parameters in heating nano magnetic particles.
(a) Type of probe used (solenoid, pancake & sandwich).
(b) Concentration of sample (Fe3O4 in… water, PBS buffer, blood, chicken breasts etc.)
(c) Time of AEM field exposure on heating and to optimize the conditions.
Later, this study may be extended to Fe3O4 coated NGP.
Related Publications :
Jin, H, Hong, B., Kakar, S.S., and Kang, K.A., “Tumor Specific Nano-entities for Optical Detection and Hyperthermic Treatment of Breast Cancer,” Oxygen Transport to Tissue XXIX; Series: Advances in Experimental Medicine and Biology, Vol. 614 Kang, K.A.; Harrison, D. K.; Bruley, D. F. (Eds.), p. 275-284, 2008 Jin, H. and Kang, K.A., “Application of Novel Metal Nanoparticles as Optical/Thermal Agents in Optical Mammography and Hyperthermic Treatment for Breast Cancer,” Adv Exp Med Biol., 599, Oxygen Transport to Tissue XXVIII (Maguire, D.J., Bruley, D.F., Harrison, D.K., eds.), p.45-52, 2007.
Technical expertise : AEM Unit
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Non Thesis & Others :
Name : Zhuoliang YeGroup & Lab :e-mail : [email protected]
Brief about Research :
“Studies on desorption of CBH1 from BMCC substrate as a function of enzymatic activity”Desorption of CBH 1 from BMCC substrate was studied here as a function of enzymatic activity. CBH1 was first separated from Spezyme CP cellulases by ion exchange chromatography. The CBH1 and BMCC were incubated together for two days. Free enzyme in the solution was monitored during this period. The maximum adsorption capacity of CBH1 was about 4 mol/mg BMCC. At an enzyme loading of 2.1 mol/mg BMCC, almost all CBH1 adsorbed onto the substrate. The CBH1 showed different desorption behavior depending on
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enzymatic activity. Desorption was quantified by measuring CBH1 content in the buffer solution using the Bradford Assay.
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Name: Diana WildingGroup & Lab: none (Non-thesis)E-mail: [email protected]
Research: Currently: Groundwork for Education in Mathematics and Science Fellowship (UofL/NSF)Previously: Inorganic biochemistry --dirhodium anti-cancer complexes
Publication:Mapping of Factor XIII Solvent Accessibility as a Function of Activation State Using Chemical Modification Methods, Brian T. Turner, Jr., T. Michael Sabo, Diana Wilding, and Muriel C.Maurer, Biochemistry, 2004, 43 (30), pp 9755–9765Link: http://pubs.acs.org/doi/abs/10.1021/bi049260%2B
Technical expertise: NMR, IR, UV-Vis, Nanosecond laser, MALDI-TOF MS
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Name: Stewart McCollamGroup/ advisor : Mr. Charles Staff, Director of the Food Processing Programe-mail : [email protected] about Research :My research activities include working at the University of Louisville Food Processing Lab performing various testing for outside companies ranging from shelf life testing, particle size analysis, and product formulation.
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Name: Jackie ParrisGroup & Lab : Non thesis (no advisor)e-mail : [email protected] about research :