The 18th Annual
NC State University
Undergraduate Research Symposium
Physical & Mathematical Sciences
Abstracts
Abstracts
are listed in alphabetical order by the last name of the corresponding author.
- Biological Sciences abstracts
Applied Sciences
(Crop, Poultry, Animal, and Horticultural Sciences)
Ecology,
Environmental, Conservation, Botanical
Molecular,
Biochemical, Genetics, Cell Biology
Zoology,
Physiology, Behavior, Neurobiology
- Design abstracts
- Engineering and
Technology abstracts
- Humanities, Social
Sciences, Psychology abstracts
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Adamek, Evan R. |
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Department(s):
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Physics |
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Research |
Hans D.
Hallen/Physics |
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Title of
Presentation: |
Nanoscale-defined,
In-plane Oriented Molecular Deposition |
The goal of this
project is to determine the efficacy of the use of an NSOM device with a
split-tip probe in the creation of circuits based upon molecules that oriented
in the plane of the surface and defined to nanoscale dimensions. To accomplish this, a sample consisting of a
thin film of Poly p-Xylene Tetrahydrothiophenium Chloride (PPTC) will be
created using spin coating techniques with a thickness of 10 to 20 nm. Then, the near field scanning optical
microscope (NSOM) will be used to orient and deposit the molecules from the
solution. This will allow for electrical
measurements to be made to ascertain the properties of the molecular device, particularly the resolution
of the electrical pathways. In this
presentation, I will describe the method of preparation for the samples that
will be used in the NSOM. The important
variables to consider are the dilution of the PPTC, which determines the
thickness of the film upon spinning, and the lifetime of the sample as well as
what measures must be taken to extend this lifetime.
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Burger, Erika E. |
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Department(s):
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Statistics |
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Research |
William F.
Hunt, Jr./Statistics |
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Title of
Presentation: |
Analysis of
Water Quality Tests |
Water quality is
currently analyzed through a serious of benthic tests. These tests report a stream’s specific
conductance, bio-classification as well as the total and relative numbers of
EPT species living in and around that sample area; a biotic index that is based
on the total and relative number of EPT species and individuals is also
recorded. EPT species is an acronym for
three pollution sensitive families of insects that live in the benthic zone. We are testing to see whether or not toxicity
tests done on the water and sediment of a stream can produce equally valid
results compared to benthic tests.
Toxicity tests are used to determine the toxicity of discharges to
sensitive aquatic species. With our
database, we have divided the data into two sections: analyses with a numerical
result, or analyses with a qualitative result.
We have also mapped the locations for these tests and divided them into
two regions of North Carolina: Mountains and Piedmont. Through statistical
regression and histogram analysis we were able to label each test as “good,”
“okay,” “bad,” “undecided,” or “non-significant.” We based these conclusions on whether the
toxicity test results (numerical) corresponded to the correct benthic results
for that location. If the toxicity test showed a bad result, we looked at the
benthic tests to see if the water had high specific conductance, low number of
EPT species as well as low EPT relative abundance. Our conclusions show varying degrees of usefulness
for different toxicity tests. A few
limiting factors, such as small samples, impeded further in-depth analysis, but
overall some toxicity tests show great promise as true, reliable indicators of
water quality.
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Cessna, Jennifer L. |
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Department(s):
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Marine, Earth,
and Atmospheric Sciences |
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Research |
Karl W.
Wegmann/Marine, Earth, and Atmospheric Sciences |
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Title of
Presentation: |
Analysis of
Summit Plateaus in Western Mongolia: Uplifted and Preserved Paleoerosion Surfaces
or the Intersection of Topography with the Glacial Buzzsaw? |
Many
tectonically active mountain ranges in western Mongolia have high elevation,
low-relief summit plateaus (LRSP). These surfaces have classically and recently
been interpreted as fragments of a preserved low-elevation erosion surface
dating to the Mesozoic that has been elevated by more recent mountain uplift
(Jolivet et al., 2007). The goal of this research is to test the hypothesis
that these surfaces represent an ancient erosion surface. Alternatively, these
flat surfaces may represent the intersection of growing mountain topography
with the latitudinally-controlled average Quaternary glacial equilibrium line
altitude (ELA), also known as the glacial-periglacial buzzsaw. A SRTM 90 m
digital elevation model (DEM) was used to extract topographic metrics, such as
relief, slope, and surface area along latitude and longitude transects. A total
of 25 individual ranges were clipped from the DEM between 43.5° N to 51° N latitude and
88.5° E to 103.5° E longitude. From these, low-relief
summit surfaces were defined by extracting contiguous areas with slopes ≤
7°
occurring
above the mean elevation of an individual range. The mean Quaternary ELA
decreases from 3350 m at 45° N to 2250 m at 51.5° N. Across the
same north to south transect the lower periglacial limit elevation (PLE)
decreases from circa 2900 m to <1000 m. We find a slight northward decrease
in the mean plateau elevation with latitude (r2=0.18) concomitant with slight
south-to-north increases in maximum summit elevations (r2= 0.10) Ranges with a
maximum elevation below the PLE do not have LRSP. Ranges with a maximum
elevation between the PLE and ELA contain larger LRSP areas; however the summit
surface size decreases for ranges above the ELA. Ranges significantly above the
Quaternary ELA experience effective glacial erosion and subsequent reduction in
LRSP areas. Preliminary results may reflect the interplay of climate and
topography rather than preservation and uplift of a >100 Ma erosion
surface.
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Cumbie, Rebecca V. |
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Department(s):
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Marine, Earth,
and Atmospheric Sciences |
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Research |
Gary M.
Lackmann/Marine, Earth, and Atmospheric Sciences |
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Title of
Presentation: |
A Case Study
on Tropical Cyclone Intensification |
It is not fully
understood how the environmental variables that interact with a tropical
cyclone (TC) affect its intensification.
A case study was performed analyzing Hurricane (H) Humberto and Tropical
Storm (TS) Grace, two TCs that occurred in similar environmental conditions.
The purpose of the study was to determine the environmental factors most
important in TC intensification by determining the cause of the storms'
intensity difference. Emphasis was
placed on the environmental variables sea surface temperature (SST), ocean heat
content (OHC), and wind shear in the study.
Results indicate that wind shear was responsible for the difference in
intensity. SSTs for TS Grace were on
average 1oC greater than they were for H Humberto, but SSTs for both
storms were several degrees above the 26.5o threshold necessary for
TC development and intensification.
Before genesis, TS Grace traveled over waters with significantly more
OHC than H Humberto traveled over. From
genesis to landfall, OHC was greater for TS Grace than for H Humberto by an
average of 10 KJ/cm2. Shear under 20
knots is considered favorable for intensification. Wind shear directly over both storms ranged
from approximately 5 to 14 knots. Shear
in excess of 20 knots was present to the immediate east and west of TS Grace
while shear near H Humberto remained under 20 knots. Wind shear was the only environmental variable
found in the study to favor intensification of H Humberto over TS Grace. It was
enough to outweigh favorable SSTs and OHC and limit TS Grace's intensification.
Placing a large emphasis on the role of wind shear when predicting future TC
intensification may significantly improve intensity forecasts and help
hurricane-prone areas better prepare.
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Gardner, Laura K. |
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Department(s):
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Chemistry |
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Research |
Reza
Ghiladi/Chemistry |
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Title of
Presentation: |
Catalase and
Peroxidase Studies of the KatG Mutants H270C and H270Y |
Treatment of
tuberculosis (TB), an infection caused by the pathogen Mycobacterium tuberculosis (Mtb),
is done with various antibiotics, the most common being isoniazid (INH). INH is
a pro-drug which is activated within Mtb
by the hemoprotein KatG. Isoniazid resistant strains of Mtb have become more widespread in recent years, and though the
cause of antibiotic resistance is not completely clear, it is thought to be
related to the mechanism of activation of INH. Isoniazid undergoes a series of
significant intermediates before it can form an adduct with NADH, termed the
INH-NADH adduct, which is believed to be the in vivo “activated” mycobactericidal agent. How the bifunctional
KatG, possessing both catalase and peroxidase activities, is involved in this
reaction pathway is unclear. Thus, to further understand how this enzyme is
related to drug activation and possibly drug resistance, comparative studies of
both wild type KatG and mutated KatGs have been performed. In particular,
spectroscopic studies of the KatG mutants H270Y and H270C have been undertaken
to determine how mutations located close to the iron active site affect the
catalase and peroxidase activities of the enzyme. UV-Visible spectroscopy
revealed that the mutation at this location does change the position of the
Soret peak of the protein as well as its kinetic activity. Further study of the
affect of mutations in this enzyme will help to elucidate the steps INH
undergoes to form the INH-NADH adduct and possibly indicators of INH
resistance.
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Gore, Kristen L. Bader, Nicole J. Gaddis, Marshall G. |
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Department(s):
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Statistics |
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Research |
William F.
Hunt, Jr./Statistics |
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Title of
Presentation: |
Meteorologically-Adjusted
Particulate Matter Trend Analysis |
Fine particulate
matter (PM2.5) is a complex mixture of tiny solid and particles suspended in
the air that have an effective aerodynamic diameter of 2.5 micrometers or
less. These particles can impose a variety
of harmful health effects due to their ability to enter the respiratory and
cardiovascular systems. A national
ambient air monitoring program was initiated in 1999 to monitor PM2.5. In 2001, the EPA implemented the Nitrogen
Oxides State Implementation Call (NOx-SIP Call) in an effort to mitigate ozone
formation. However, the ability to
measure the true effectiveness of emission control legislation is complicated
by the impact of meteorological factors on ambient air quality. By creating an autoregressive linear model
which accounted for meteorological variables, it was determined that the
NOx-SIP Call was successful in reducing ozone in North Carolina, Maryland, and
New Jersey [“Meteorologically Adjusted Ozone Trend Analysis.” Antczek, Brown, Gore,
et al. (NCSU) 2007]. Did the NOx-SIP
Call reduce North Carolina’s PM-fine concentrations, as well? The purpose of this project was to evaluate
the effectiveness of the NOx-SIP Call in curbing PM concentrations. Exploratory statistical methods were applied
to continuous hourly PM2.5 and meteorological data, which were collected at the
Raleigh Spring Forest Road site from November 1998 to January 2007. No
significant change was found in PM2.5 levels after meteorological factors were
removed using an autoregressive statistical method, despite the reduction in
utility-related NOx emissions.
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Greene, Jodie |
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Department(s):
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Chemistry |
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Research |
Chris
Gorman/Chemistry |
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Title of
Presentation: |
Synthesis of G2
Dendrimer |
Iron sulfur proteins are vital to maintaining homeostasis in the human
body, transportation of electrons in various electron transport chains,
regulation of gene expression, and facilitation of substrate binding and enzyme
activity. The redox potential of the iron sulfur proteins are very dependent on
the protein environment around the cluster.
Understanding the structural features of these proteins will provide a
better understanding how environment controls the redox potential of the iron
sulfur cluster. Using dendrimers, we can
isolate the iron sulfur cluster, which allows us to eliminate the effect of the
solvent environment on the redox potential of the iron-sulfur cluster. The half
hydrophobic, half hydrophilic nature of these particular dendrimers is
envisioned to encapsulate the cluster by exhibiting lipid-like properties and
wrapping around the iron sulfur cluster.
The hydrophilic end will allow the iron sulfur cluster to facilitate
electron transport and dissolve in polar solvents. Thus, it is hypothesized that this structure
will have the dual role of core protection and water solubility. Dendrimers are being prepared in different
generations (the number of layers of hyperbranching). The second generation dendrimer has been explored
to see if the branching of the dendrimer will protect the iron sulfur cluster
and still allow electron transport to and from the cluster core. The dendrimer is synthesized through a series
of multistep organic reactions, and then the electronic properties of the
dendrimer are invested through electrochemistry.
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Guignard, Lewis B. |
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Department(s):
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Physics |
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Research |
Harald
Ade/Physics |
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Title of
Presentation: |
Layered
Organic Photovoltaics |
Organic polymers and their applications to electronics is an
exponentially growing field, showing the promise of cheaper, lighter and more
flexible hardware. The particular focus in this research is with solar cells,
and the fabrication techniques of polymer layers. The chemicals used to produce
an electrical difference are P3HT and PCBM, which can respectively yield a
positive and negative charge. These two don't give up electrons as easily as a
silicone substrate however; the electrons and 'holes' don't differentiate from
photoexcitons with out a favorable potential energy difference. The threshhold
between P3HT and PCBM will provide this energy difference, allowing the
electron to escape and current to be created.
Problems arise when adding these layers of substrate to each other. To
reach the required thickness, they are spun-cast in a solvent solution. The
solvent of any new layer will dissolve a 'set' layer below it. In at least
three publications, successful methods have been described where the researchers
have used certain temporary buffers and certain solvents to produce the
requisite layers of polymer in the laboratory.
My research focused mainly on trying to replicate these methods here at
NC State. Although successful in laying layers of the same material on top of
each other, I found that different materials layered with this technique proves
much less effective and reliable. This presentation will outline the general
usefulness, operations of, and techniques for synthesizing organic solar cells,
as well as my specific results in attempting bilayer spin-coating with
different buffers.
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Hampson, Max M. |
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Department(s):
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Physics |
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Research |
Hans D.
Hallen/Physics C. Russell
Philbrick/Physics; MEAS |
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Title of
Presentation: |
Measuring Aerosol Optical Thickness via Diode Laser
Extinction |
Detecting the presence of small particulate matter is vital to
quantifying their effect on health and ecosystems. In this research, an attempt
is made to design and construct a cost effective method of detecting local
aerosol scatterers. The main contribution to Aerosol Optical Thickness (AOT) is
from scattering by particles whose size is close to the wavelength of incident
light. Diode lasers transmitting at three wavelengths are selected: 407.5, 532, and 655 nanometers. These lasers
are made collinear via a system of dichromatic mirrors. The beam is then
expanded in a beam expander and transmitted onto a distant photodiode detector.
By measuring the intensity at each wavelength before and after transmission,
the extinction can be quantified and a AOT determined
as function of Rayleigh optical thickness and air mass.
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Hewitt, Andrew |
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Department(s):
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Physics |
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Research |
Daniel
Dougherty//Physics |
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Title of
Presentation: |
Electronic Spectroscopy of Organic Semiconductors
in Planar Magnetic Junctions |
The developmental field of spintronics envisions the generation,
transport, and detection of spin polarized electrical currents for low power,
high speed device applications. Maintaining spin polarization allows the
intrinsic spin of electrical carriers to be used as the physically relevant
device parameter rather than their charge as in traditional devices. This
innovation could result in higher performance devices and also novel device
applications (e.g. quantum computing) but first new materials must be developed
and characterized for the purpose of coherent spin transport. Organic
semiconductors are promising candidate materials for spintronic applications.
In order to characterize these materials in solid state environments, we have
designed and commissioned an apparatus to measure electronic spectra of organic
semiconductors sandwiched inside ultrathin metal-insulator-metal tunnel
junctions.
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James, Jennifer J. Clark, Camille A. Rice, William J. |
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Department(s):
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Statistics |
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Research |
William F. Hunt, Jr./Statistics |
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Title of
Presentation: |
Crustal
Matter: Exploring the Differences between Ambient Air Samples and Emissions
Inventory |
Fine particulate matter (PM2.5) is a complex mixture of tiny particles
in the air. PM2.5 consists of particles
that measure 2.5 micrometers in diameter or less, and is composed of sulfates,
metals, crustal matter, and other elements.
Crustal matter is simply fugitive dust or soil originating from the
earth’s surface. This project is
concerned with the ratio of crustal matter to PM2.5. Actual ambient air samples
from 2002 suggest the ratio of crustal to PM2.5 is 5% to 10% where as the 2002
emission inventory estimate of the ratio is 27.5%. This study is being conducted to better
understand this disagreement. Current
findings have found a large source of the discrepancy as a simple
miscommunication. The PM2.5 measured by
ambient monitors is total PM2.5, which includes both primary and secondary
PM2.5, whereas the emission inventory reports only primary PM2.5. However, after computing the ratio of crustal
matter to primary PM2.5 for the ambient data, a discrepancy, although smaller,
still exists. This work will result in
recommendations that will encourage a closer agreement between ambient samples
and the emission inventory, which may improve the air quality management process.
It is critical to explore this incongruity so the US EPA, along with other
environmental agencies, will take necessary action to use the most accurate and
useful ratio for their specific purposes.
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Kan, I Wei (Grace) |
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Department(s):
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Chemistry |
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Research |
Reza Ghiladi/Chemistry |
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Title of
Presentation: |
Correlation of
KatG Mutants to Isoniazid Resistance in Tuberculosis (TB) |
Tuberculosis (TB) is one of the leading causes of death due to a single
disease, claiming about two million people annually, primarily in developing
countries. Efforts to control TB infection have been hampered by the rise of
multiple-drug resistant strains, which include resistance to isoniazid (INH),
the most widely prescribed antibiotic used to treat TB. 50% of multiple drug
resistant tuberculosis are found in China and India. While it is now generally
accepted that INH is a pro-drug which is activated by the catalase-peroxidase
KatG, the specifics of this activation process have to-date proven to be
elusive, and further study is necessary for rational drug design of antibiotics
to combat TB. KatG, a catalase-peroxidase, is the protein found in Mycobacterium tuberculosis that
activates INH, and it has been shown that point mutations in KatG lead to
INH-resistant strains of TB. Most
INH-resistant strains lack the KatG gene or have mutations, deletions, or
insertions. This results in a conformational change in the protein, preventing
the perfect “lock and key” fit most enzymes have with their substrates. I have
designed four KatG mutants, L148A, L587M, D735N, and N138H, which have been
recombinantly expressed in E. coli,
purified to homogeneity. Peroxidase activity in terms of reactivity and
concentration for L587M was measured and compared to wild-type strains’
characterisitics. The next steps are to characterize the all mutants for
catalase and peroxidase activities along with their INH-NADH adduct forming
ability with peroxide.
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Kenny, Samuel G. |
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Department(s):
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Physics |
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Research |
John Blondin/Physics |
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Title of
Presentation: |
The
Characterization of a Physical Model of Accretion: SS CYG |
For over thirty years, observational studies of SS Cygni, in the
constellation Cygnus, have shown a pronounced periodic variability in the
apparent luminosity and relative position of the star. Observations of its
spectrum have revealed it to be an abundant source of UV rays with occasional
outbursts of X-rays. These two observations are indicative of the existence of
a cataclysmic variable. In this system in particular, the donor secondary, a K
type star of ~0.6 solar masses, transfers mass to a white dwarf primary of ~0.4
solar masses by means of an accretion disk. For years, these objects have been
studied according to a mathematically rigorous, “semianalytical” approach. This
method assumes that the disk is in relative equilibrium and often ignores some other
aspects of the system. In recent years with the advent of supercomputers, many
have begun testing theories of accretion disks using hydrodynamics simulations.
However, most have neglected the accretion stream since it was not
computationally feasible with the available resources at the time. Now these
resources are available. We present a hydrodynamic model of the SS Cygni binary
stellar system using an isothermic equation of state developed by Dr. John
Blondin. We characterize the system both qualitatively and quantitatively.
First, we observe the flow out of the L1 region to confirm Lubow & Shu’s
semianalytical result (1975). Next, we observe how material flows through the
system to understand how angular momentum is transported through it. Finally we
quantify the aspect ratio of the accretion stream to observe how it changes
with distance from the donor star. We use a visualization software package
called EnSight for qualitative analysis and data gathering. We have developed
multiple codes to analyze and reduce the gathered data.
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Leone, Jason T. Gore, Kristen Pearce, Jamie |
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Department(s):
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Statistics |
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Research |
William F. Hunt, Jr./Statistics |
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Title of
Presentation: |
Forecasting
Wildfires and Examining the Extent of Global Climate Change |
Extending into late November 2008, fires continued to burn in California
causing the evacuation of homes and the destruction of property. The western region of the continental United
States continues to see devastating fires.
The United States Environmental Protection Agency (USEPA) is interested
in this increase in wildfires, the possible causes, and the emissions released
from these fires. One important factor
to consider in conjunction with an increase in wildfires is an increase in
temperature. The Northern Hemisphere has
shown an increase in temperature anomalies steadily over the last thirty to
forty years. Similarly, over the last
forty years there has been a positive trend in national temperature as well as
western and northwestern regional temperatures.
At the same time, there have been increases in the acres burned
nationally and in the acres burned per fire on annual average. When compared over the 24 year period
1983-2007, we have observed an increase from approximately two million acres
burned per year (or 30 to 40 acres per fire) in 1983 to eight million acres
burned per year (or over 100 acres per fire) in 2007. During this period, there has been increase
of about 2 to 2.5 degrees Fahrenheit.
Because not all regions in the United States have the same climatic
problems and geological make-up, it is important to analyze trends in States to
develop more precise models using temperature, relative humidity, lightening
strikes, etc.. It is our goal to develop
a model to forecast wild fires for the Western United Sates and predict a
potential impact from future global climate change. Hopefully, the USEPA will be able utilize our
results to improve future State Implementation Planning for fine particulate
matter and increase our understanding of possible impacts of global climate
change.
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Lichtenberger, Adele M. |
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Department(s):
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Physics |
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Research |
Karen Daniels/Physics |
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Title of
Presentation: |
Surfactant
Spreading on Thin Liquid Films |
When a surfactant is placed on a thin liquid film, it will spread
radially outward and reduce the surface tension of the underlying film, causing
the film to thin behind the surfactant front.
While the resulting surface tension gradients can cause fingering of the
spreading front, the circumstances under which it happens are poorly
understood. Therefore, we have conducted
experiments to understand the controls on this behavior. We study surfactant spreading on a thin film
of glycerin (~1mm thick) on an aluminum plate.
A drop of fluorescently-tagged surfactant is placed inside a ring in the
center of the plate, and then the ring is slowly lifted to allow both fluids to
spread outward. We induce fluorescence
of the surfactant with a UV light, and a laser line gives the height profile of
the film; a camera mounted above the plate allows us to track both
simultaneously. Two surfactants,
phospholipids of different lengths, have been used, with similar results. We observe that a uniform spreading front is
stable, and that induced fingers are not sustained.
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Long, Brandon J. |
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Department(s):
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Physical and Mathematical Sciences |
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Research |
Hans D. Hallen/Physics |
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Title of
Presentation: |
UV Resonance Nano-Raman
Spectroscopy |
Raman Spectroscopy is an invaluable tool for identifying and
characterizing materials, but often suffers from both weak signal and the need
for better resolution. Nano-Raman measurement using a Near-field Scanning
Optical Microscope (NSOM) can greatly improve the resolution independent of the
wavelength. The traditional nano-Raman signal is very small, because of the
small volume (number of molecules) sampled, making imaging impractical.
However, UV resonance Raman can solve the signal problem. We have therefore begun construction of an
all-reflective nano-Raman system, that will
incorporate tunable deep UV excitation for resonance Raman capability. We have
constructed much of the NSOM instrument, created most of the necessary electronics,
and used micro-Raman to test the spectrometer and determine what features can
be seen in nano-Raman scans.
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Orbon, Benjamin N. |
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Department(s):
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Chemistry |
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Research |
Lin He/Analytical Chemistry |
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Title of
Presentation: |
AGET ATRP
Polymerization in Microfluidic Device for Biosensing |
A handheld, easy-to-use, genetic DNA testing device may serve doctors to
quickly and efficiently test patients for genetic diseases such as Alzheimer’s
and even provide a new, non-invasive method to find the gender of an unborn
baby. This technology may seem complicated, and distant; But a system built on
the concept of amplification-by-polymerization may help to create such a device
in the near future. Atom transfer radical polymerization (ATRP) has become a
common controlled-living radical polymerization used in polymer science due to
its controlled chain growth rate and efficiency. Our past research has shown
that this industry-based polymerization method can be used for DNA biosensing
to sense genetic mutations. In this study, activators generated by electron
transfer (AGET) ATRP has been carried out in a microfluidic device, which
provides the first step to creating such a DNA sensing device and paves the way
for the fabrication of future home-care DNA biosensor kits. The microfluidic
channels were fabricated on a silicon surface. The results suggest channel
fabrication to be most reliable using Norland Optical Adhesive (NOA 81), rather
than a common polydimethylsiloxane (PDMS) method. Application of
(3-aminopropyl) trimethoxysilane (APS) prior to initiation were conducted by
submersion or reflux. Submersion in a 1% solution of APS in Methanol provides
the most effective method. Polymer growth can be increased or decreased by
altering initiation reaction time, or by altering polymerization time.
Together, the data produced provide understanding in the behavior of AGET ATRP
in microfluidic channels and can give models to apply to DNA-based reactions.
The conclusions forward our understanding of these reactions and make handheld
DNA biosensors a step closer to reality.
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Somers, Steven G. Myers, Ashley N. Burger, Erika E. |
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Department(s):
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Statistics |
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Research |
William F. Hunt Jr./Statistics |
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Title of
Presentation: |
Can Blood Lead
Levels in Children Be Reduced? |
Lead exposure, whether acute or chronic, is a serious public concern due
to the associated health hazards.
Chronic lead poisoning is more common among children under the age of
six and can have severe adverse effects on their cognitive development and
behavior. Even low levels of lead
intake, previously thought to be harmless, have been shown to cause damaging
effects after prolonged exposure. Our
objective is to investigate Elevated Blood Lead Level (EBLL) rates per 1000
children. We have compared the 2003
California EBLL data to another EBLL data set they submitted in 2006 and found
the 2003 data to be incorrect. We have
contacted other state officials to validate the integrity of all the data and
have also contacted states that didn’t submit data to the CDC in hopes of
gaining access to their data. We are
hoping to predict EBLLs as a function of environmental factors and believe
different regions of the country will have different significant factors. We
have also produced a map that depicts the concentration of EBLL rates which
highlights the rustbelt as the main area of concern for our nation. Using exploratory statistical methods, we
hope to better inform the US EPA of areas with high EBLL. Our final objectives are to provide a more
accurate data base than the one currently available for the CDC, provide
recommendations for the US EPA and at home prevention, and attempt to determine
the next major contributor to the current high EBLL in children. Exploratory statistical methods will be used
to determine the accuracy of the data submitted to CDC, provide a better
estimate of the extent of the problem, and possibly highlight environmental
factors causing the problem in each different region of the continental United
States.
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Woody, Susan M. |
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Department(s):
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Chemistry |
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Research |
Lin He/Chemistry |
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Title of Presentation: |
Genetic
Detection of Human Sex Chromosomes Using PCR and RAFT Polymerization Reaction |
Current methods of detecting small portions of DNA such as the
Polymerase Chain Reaction, or PCR, coupled with gel electrophoresis, often
require sophisticated equipment and visual aids for detection. However, a new
method of DNA identification known as amplification-by-polymerization using the
Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization reaction
has been shown to be able to quickly identify small segments of DNA with high
sensitivity and without the requirement of a visual aid. The ultimate goal of
my research project was to take this idea even further, and use RAFT
polymerization for visible detection of the sex chromosomes (X and Y) in human
genomic DNA such that it was possible to distinguish between male and female
genders in genetic screening. This type of identification could be used for
early-stage non-invasive pre-natal gender determination because it only
requires a small amount of blood sample from the mother and thus would limit
disturbance to the fetus. In the first
line of my experiments, unknown samples of isolated genetic material were
amplified by PCR to provide orthogonal gender determination of unknown patient
samples. Critical experimental variables during PCR were optimized, including
the selection of the polymerase, the DNA ladder, and the staining dye for gel
analysis. Among 27 unknown samples tested, 7 samples were positively identified
as male, 12 as female, and 8 yielded inconclusive results due to a lack of
starting template. In parallel, the second line of experiments was conducted to
examine the gender identification of the same samples via the RAFT
polymerization. Concept-proof experiments to identify complementary short
oligonucleotides were demonstrated. Continuous work on optimization of genome
DNA hybridization is underway before PCR-free RAFT screening of gender-specific
sequences can be successfully carried out.
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Last modified January 2009 by Sharon E. Hunt, WordHunting