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Former Members of Team Weimer


Chad Smith
Graduate Student
“Hydrogen generation via hydrolysis of zinc in a high pressure fluidized bed”
The goal of my research is the investigation of a viable means to split water and recover hydrogen as a renewable fuel source. In the realm of thermo-chemical water splitting technology, an attractive approach is the two-step Zn/ZnO redox cycle:
ZnO → Zn + ½ O2 ( high-temperature solar decomposition) (1)
Zn + H2O →ZnO +H2 (low temperature water splitting) (2)
My work focuses on the low temperature water splitting portion of this cycle where hydrogen is generated. My investigation includes: determining fluidization behavior of zinc nanopowders; designing and implementing a fluidized bed reactor of zinc nanopowder to carryout the water splitting reaction at high pressures; modeling the reactor to determine the kinetic properties and transport contributions of the reaction.


Casey Carney - More Casey Info
Ph.D.
Student and Post-doctoral Associate


Gevorg Sargysan
Undergraduate Researcher


Amanda Scott
Undergraduate Researcher/REU Student


Andrea Frances
Undergraduate Researcher/REU Student


Lauren Brickner
Undergraduate
Researcher


Henry Diaz
Undergraduate
Researcher

Luis
Hakim (a.k.a. "Mad-Mex")
Ph.D.
Student
"Surface modification of nanoparticles via
Atomic Layer Deposition"
My
main project goal is the application of ultrathin films on the surface of nanoparticles via
Atomic Layer Deposition using a fluidized
bed reactor. This technique
allows for modifying the surface of ultrafine particles while maintaining their
bulk properties. Applications of
this development range from microelectronics and high-performance materials to targeted-drug delivery and advanced cosmetic
products.
This
is a very novel development since conformal, non-granular, pinhole-free coatings
had never been applied to bulk quantities of nanoparticles before. I am also
interested in studying the new physical and chemical properties provided by the
thin films as well as the effect of such films on interparticle
forces.
Luis
is now a Process Development Engineer at Novellus
Systems


Sophia
Haussener
Visiting
M.S. Student
Simulation, efficiency calculation and optimization of a
solar reactor, which is used for the endothermic, high temperature step of the
zinc/zinc-oxide redox cycle to produce hydrogen.


Dave
Hutson
Undergraduate
Assistant


James
Wollmershauser
Professional
Research Assistant
"Silica-coated
Boron Nitride Particles for Microelectronics Packaging"
Selectively coating only the edges (not the basal planes) of BN
particles is desirable for increased wettability and interfacial adhesion of the
BN edges within a polymer matrix while maintaining a high thermal conductivity
via direct BN basal plane stacking. This project provides for the development of
improved boron nitride (BN) filler materials for electronic thermal management
applications. Novel Atomic Layer Deposition (ALD) nanocoating is used to
selectively functionalize edges only and edges/basal planes to improve wetting
of BN platelets with resin encapsulants. The improved wetting allows for
significantly reduced viscosity (~ 5 times less) of BN/resin mixtures during
processing and improved interfacial adhesion in the cured composite. These
improvements are realized by placing an ultra-thin (nm thick), conformal,
pin-hole free, chemically bonded SiO2 nanofilm on individual BN particles.
James
is now a Ph.D. student in Materials Science at University
of Virginia


Candace
Vaughn
Undergraduate
Researcher
"Production
of oxidation-resistant fine metal powders"
My project
focuses on the use of a Thermal Gravimetric Analyzer to
determine the feasibility of production of fine metallic powders via the
reduction of their oxides. By measuring the dynamic mass loss of the oxide
sample during reaction (time, temperature), it is possible to calculate
the activation energy and other kinetic rate parameters for the reduction
reaction. The synthesized powders are then characterized by X-ray diffraction,
oxygen content, microscopy, and surface area.
Some of
the critical parameters that define optimum reduction process are the gas environment,
the ultimate reaction temperature, and the ramp temperature program.
Ultimately, the fine metals will be passivated by coating the particles
with a ceramic layer using Atomic Layer Deposition. This process creates
a very conformal film on the surface of the
particle that acts as a barrier for diffusion of oxygen, thus, increasing
the oxidation-resistance of the powder.


Guodong Zhan
Sr.
Research Associate
"Atomic Layer Deposition Nanomaterials Synthesis,
Characterization, and Applications
"
My research interest is focusing on the design, synthesis, characterization,
and properties of ultrathin films and nanostructures via the atomic layer
deposition (ALD) technique. I am currently working on a number of projects and topics including ALD of
ultrathin, conformal nanocoating on particles such as ALD on fine copper
particles for quantum tunneling applications, ALD of inorganic films on polymers
such as ALD on carbon nanotubes, fabrication and properties of
nanolaminate composite materials and bulk nanocomposites from ALD coated
powders, thin film growth, and various technological applications such as application of Particle-ALDTM
and Polymer-ALDTM to phosphor particle functionalization and the
fabrication of luminescent devices.

Margarite
Parker
Undergraduate
Researcher
"Second
Step of metal oxide cycle for solar thermal water splitting"
For
my project, I am working as assistant to Hans Funke in reacting zinc with water
to produce hydrogen, the second step of a two part reaction. For information on
the first step, please see Chris Perkins’ description. I chose this project
because I am interested in alternative-energy sources, one of which is the
“hydrogen economy”. Thus, much more research needs to be done in order to
produce hydrogen from non-polluting means. In
the labs, I am working on setting up all the equipment to run the reaction (mass
flow controllers, mass spectrometer, temperature controller, e.g.). We are
reacting zinc powder, with nitrogen as the inert gas, with water vapor to
produce hydrogen. We are taking the partial pressure of hydrogen to determine
the actual amount produced, compared to what would be produced in an ideal
reaction, and ascertain the temperature and flow rates that would produce the
best results. Thus, we are not collecting any hydrogen at this moment, just
testing the parameters that influence the effectiveness of the reaction.

Heather
Dunsheath
Undergraduate
Researcher
"Production
of Nanosized Metal Particles"
The
interest in ultrafine metal nanoparticles has been increasing in the past few
decades. However, due to their high surface area, nanosized metal particles
rapidly oxidize when exposed to air. Metal nanoparticles can be produced from
the decomposition of their oxalates. However, optimization of the particle size
of the oxalate particles is required before the decomposition step. A
novel method to reduce the particle size of the oxalate particles was developed.
Sub-micron particles were obtained after only a few hours of processing.
Further reduction of particle size was observed during the decomposition of the
metal oxalates.


Jennifer
Walsh
Ph.D.
Student
"Thermophoretic
Deposition of Aerosol Particles in Laminar Flow Tube with Mixed Convection "
Thermophoresis is the term describing the fact that small
particles suspended in a gas will acquire a velocity in the direction of
decreasing temperature. This phenomenon
is important in a variety of applications such as the production of ceramic
powders in high temperature aerosol flow reactors, and production of optical
fiber performs. The gas
molecules coming from the hot side of the particles have a greater velocity than
those coming from the cold side. The
faster moving molecules collide with the particles more forcefully. This difference in momentum leads to the particle developing a velocity
in the direction of the cooler temperature.


Dr.
Chris Gump (a.k.a. "The Reverend")
Post-doctoral
Associate
"Development
of Rapid Reaction Technology"
My research involves the understanding and
development of an aerosol flow transport tube reactor for various advanced materials. The reactor is
capable of operating at up to 2673 K (graphite reacton tube) and allows for the
rapid heating (~ 1 million degrees/sec) of
reactant particles to form fine powdered products. We have successfully
synthesized carbide (B4C, TiC, Mo2C), nitride (AlN), and intermetallic (NiAl,
Ni3Al) materials as well as composites of those materials. The product
powders are typically submicron in size since the short residence time at
temperature limits grain growth. For most of these
materials, the very properties that make them desirable (high hardness, high
strength), make the synthesis of powdered forms by other techniques very difficult.
Chris
is now a Senior Design Engineer at ALD
Nanosolutions

Joe
Spencer (a.k.a. "Boy Genius")
M.S.
Student
"Atomic
Layer Deposition on polymeric materials"
My project is focusing
on depositing thin film layers of alumina on polyethylene particles using ALD.
These materials can later be used in improved barrier films and property
enhanced plastics.
Joe
is now a Lead Process Engineer at ALD
Nanosolutions

Michelle
Casper (a.k.a. "Chelle")
Undergraduate
Researcher
"Fluidization
behavior and nanocoating of ultrafine particles"
The
focus of my research project is the study of the fluidization behavior of
nanosized particles at low pressures. Determining parameters such as the
superficial gas velocity and bed voidage at minimum fluidization give us insight
on the special flow characteristics of nanoparticles in a fluidized bed. The
ultimate goal is to coat nanoparticles using Atomic Layer Deposition at low
pressures. The study of the effect of ceramic films on the fluidization
characteristics is also relevant.


Les
Morgret
Undergraduate
Researcher
"Atomic
Layer Deposition on fine copper particles for quantum tunneling applications"
My
research currently involves the Atomic Layer Deposition (ALD) of alumina onto
Cu particles. The fluidization behavior of
the Cu powders is investigated and the powders are then coated by ALD.
The resulting coated particles have an ultrathin conformal and chemically
bonded layer of an insulating material (i.e. alumina) on the electrically
conductive Cu particles. The nanocoated Cu powders will be electrically
pulse tested to determine if a non-linear quantum tunneling response can be
obtained. This type of response provides for an ability to reduce high
voltage (electrical surges) threats to electrical equipment very effectively.
Les is now a Ph.D. graduate student in
chemical engineering at Northwestern University


Brian
Stephens-Hotopp
Undergraduate
Researcher


Dr.
Karen Buechler (a.k.a. "Lab Lt.")
Post-doctoral
Associate
Karen
is now president and CTO of ALD NanoSolutions

Jaimee
Dahl
Ph.D.
Student
"Rapid
solar-thermal decarbonization of methane"
The objective of my thesis is to
thermally dissociate methane to carbon black and hydrogen using a solar-thermal
aerosol flow reactor. The most successful reactor design to date includes three
vertical tubes. The outer tube is quartz, which serves as a window through which
concentrated sunlight passes. The middle tube is a solid graphite tube that
absorbs the solar radiation and heats the reactant gas stream. The innermost
tube is a porous graphite tube through which argon is fed in order to create a
“gas blanket” to protect the inner tube wall from deposition of the carbon
black particles. The methane stream is fed into the center of the porous tube.
Using concentrated sunlight from a 10 kW solar furnace, the reactor wall can
achieve temperatures as high as 2100 K. At that temperature and a residence time
on the order of 10 ms, 90% conversion of methane to hydrogen can be achieved.
This is the first solar-thermal aerosol flow reactor designed to dissociate
methane at high temperatures and low residence times.
Jaimee Dahl is
now employed with BP in Anchorage, Alaska carrying out R&D in a Gas to
Liquids Development Plant


Julie
Portman (a.k.a. "Queen Amidala")
Undergraduate
Researcher
"Study
of fluidization and agglomeration behavior of nanosized particles for ALD
processing"
Atomic
Layer Deposition (ALD) allows modifying the surface of particles while keeping
their bulk properties. Recent interest has been shown in applying thin films on
nano-sized particles via ALD thru a fluidized bed processing. At
very small scales (submicron) interparticle forces become very important and
fluidization may become difficult. One of my project goals is to develop an
understanding of all the interparticle forces involved in fluidization of
nanoparticles.
The
use of multiple fluidization aids allows for reducing the natural agglomerating
behavior of ultra fine particles. Therefore conformal, non-granular, pinhole-free coatings
can be applied on primary nano-sized particles.


Jeff R. Wank
Ph.D.
Student
"Coating
Particles with Alumina Nanolayers Utilizing Atomic Layer Deposition in a
Fluidized Bed Reactor"
Jeff now works for Intel in Portland, Oregon as a Senior Process
Engineer. He is involved with process development (epitaxial thin film growth) for Intel's next generation processors.

Michelle
Zeles (a.k.a. "Cutie Pie")
Undergraduate
Researcher
Conducted research on intermetallics, ceramics
and cermets using the TGA and DTA. The focus of the research was to create
submicron particles using the TARPS method. The materials created were TiC,
NiAl and NiAl-TiC (patent-pending)


Houston
Frost (a.k.a. "Joe Cool")
Undergraduate
Researcher
"Direct
electrochemical conversion on a carbon fuel cell"
My research is on a direct carbon converision fuel cell. The direct
electrochemical conversion of carbon black to electrical energy can be accomplished using a fuel cell design. The use of a Direct Carbon Fuel
Cell (DCFC) is attractive because of its near 100% thermodynamic efficiency.
This provides a substantial improvement over the production of electrical
energy via burning carbon to provide turbine driving steam. This device is of interest
because it could work in conjunction with the solar-thermal transport reactor under development in Dr. Alan Weimer’s research group. The transport
reactor thermally dissociates methane, producing hydrogen gas and nano sized
carbon black powder. This fine carbon black powder has been found to be
highly reactive in a molten carbonate salt fuel cell, and my research
investigates the reactivity in a direct oxidation type fuel cell. The fuel
cell was found to produce an open circuit voltage of 0.8 V at 800 oC, and a
closed circuit current of 1-2 mA/cm2.
Houston is now a Ph.D. graduate student in
chemical engineering at Northwestern University
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