http://www.ncsu.edu/uap/images/ncsu_nameplate.gif

http://www.ncsu.edu/uap/images/duap_logo.gif

 

The 17th 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

 

 

 

 

 

 

Student Author(s): 

Allen, Cyril A.

Department(s):

Physics

Research Mentor(s): 

John M. Blondin/Physics

Title of Presentation:

Supernova Shear and Magnetic Field Amplification

A core collapse supernova marks the death of a star over 8 times the size of the sun. Sometimes in the aftermath of these explosions a spinning, magnetized, neutron star can be left behind, also known as a pulsar. It has recently been discovered that pulsar spins can arise through a spiral spherical accretion shock instability (SASI) of a supernova. This non-axisymmetric instability produces a strong shear flow inside the supernova shock wave, which may lead to amplification of the star's magnetic field.  The hydrodynamic simulations developed by NCSU Undergraduate student Samantha Shaw in her study of this instability (2007 Astrophysical Journal, Volume 656, p. 366) have been modified to include a tracer of the magnetic field by adding the magnetic induction equation to the code. Diagnostics were added to the code to measure the overall field strength and shear flow generated by the SASI. This has allowed a glimpse into the amplification of the progenitor field and the effects of field geometry, stellar rotation, and other parameters that might affect the evolution.  

 

 

 

Student Author(s): 

Beek, Torrey

Department(s):

Physics

Research Mentor(s): 

John M. Blondin/Physics

Title of Presentation:

Hot Molecular Gas Bubbles in NGC 1068

Our goal is to produce a three-dimensional simulation of a molecular gas complex being ablated outwards by strong winds from a quasar.  The gas complex is modeled as a hemisphere of dense material at the apex of the cloud followed by a long, cylindrical section of the complex.  This gas complex encounters a Bow shockwave from a quasar (propagating from the accretion disk of a black hole located at the center of the quasar) that converts the ram pressure of the wind into thermal pressure behind the shock.  The simulation was created using the program VH-1 to model the effects of the shockwave on the cloud and, in particular, the ablation of the heavier, more dense material within the gas complex.  From our models, we will show that the molecular gas speeds away from the nucleus of the cloud roughly proportional to the distance from the nucleus.  The challenge is to create a high resolution, three dimensional model that includes a correct model of the thermal pressure.  Our strategy will be to fix the initial conditions of the gas complex to correctly model the thermal pressure.  Once the model is complete, Dr. Gerald Cecil of the University of North Carolina-Chapel Hill will observe and interpret our model of the acceleration of the denser materials ablated from the cloud surface.   

 

 

 

Student Author(s): 

Bowen, Patrick T.

Department(s):

Physics

Research Mentor(s): 

Chueng R. Ji/Physics

Title of Presentation:

Modeling Neutrino Oscillations with Classical Mechanical Systems

 

One of the most popular inquiries in particle physics today is the flavor mixing problem.  According to the Standard Model, every flavor of neutrino has a unique lepton number, which refers to a corresponding flavor. However, neutrinos have been observed to change flavors, and this has piqued much interest in particle physics. In this paper, we propose that the flavor oscillation frequencies can be very closely modeled by a classical system of coupled pendulums.  We will solve for the eigenfrequencies of a system of three pendulums set up in a plane and coupled with two springs.  This eigenfrequency will then be compared with the known frequencies of the masses corresponding to each flavor. 

 

 

 

Student Author(s): 

Brown, Tim D.

Zheng, Jie

Gore, Kristen L.

Antczak, George

Wootten, Adrienne M.

Department(s):

Statistics

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

William F. Hunt, Jr./Statistics

George Bridgers/NC Department of the Environment and Natural Resources--Division of Air Quality

Ryan Boyles/North Carolina State Climate Office

Title of Presentation:

Did the Addition of Supplementary Control Systems at Utilities Result in Lower Nitrogen Oxides Emissions and Reductions in Ground Level Ozone in North Carolina?

 

 

Nitrogen Oxides (NOx) are important pollutants that result from the emissions of combustion processes, especially from transportation sources and utilities. NOx, and volatile organic compounds (VOC’s) are precursors of tropospheric ozone. The reaction of these precursors in the presence of solar radiation form ozone, but the formation of this secondary pollutant is also dependent on varying meteorological conditions such as wind speed and temperature. Therefore to determine the impact of emissions reductions it becomes necessary to remove the effect of varying meteorology from the ambient data. This paper focuses on the analysis of nitrogen oxide emissions in North Carolina and Tennessee to determine the impact of reductions at utilities. Ambient ozone data from four Clean Air Status and Trends Network (CASTNET) sites in North Carolina are also analyzed to determine the impact of the NOx emissions reductions by utilities. We also developed the model to find the trend in ozone levels in North Carolina after the effects of meteorology have been removed.

 

 

 

 

 

Student Author(s): 

Carpenter, Elisabeth

Moore, Spencer

Department(s):

Physics

Research Mentor(s): 

Albert Young/Physics

Title of Presentation:

Construction of a Rubidium Magneto-optical Trap to Study Surface Physics

 

We cool and trap Rubidium (Rb) atoms using a Magneto-optical trap (MOT) for use in original research in surface physics. Three orthogonal pairs of counterpropagating laser beams cool the atoms, which are ultimately trapped in a state referred to as “optical molasses” at temperatures of a few microKelvin or below. We discuss the construction and operation of the trap and present preliminary results. We also discuss the trap’s ultimate role in surface physics research.   

 

 

 

Student Author(s): 

Davis, Bryce F.

Department(s):

Physics

Research Mentor(s): 

Thomas P. Pearl/Physics

Title of Presentation:

Self-Assembly of (R,R)-, (S,S)- and Racemic Tartaric Acid

Films on Ag(111)

 

 

The forces that determine the structure of a thin film grown on a surface can be divided into two groups: those between the adsorbate and the substrate and those between the functional groups of the adsorbates.  In the case that the interaction between an adsorbate and a substrate is weak (i.e., when the adsorbate is only physisorbed), the interactions between the functional groups of the adsorbates govern organization.  A situation where this is the case, the adsorption of tartaric acid (C4H6O6) on Ag(111), has been studied with low temperature scanning tunneling microscopy.  Images of both enantiomers as well as the racemic mixture of them and the serial deposition of the pure enantiomers will be presented.  The data shows that the intermolecular forces amongst the adsorbates, namely hydrogen bonding, determine the organization of the film, with little influence from the Ag(111) surface.  This is most clearly illustrated in the fact that the film formed is chiral, a property from the tartaric acid, a chiral molecule with two stereocenters, not from the achiral Ag(111) surface.  Furthermore, the method by which the film of the combined enantiomers is grown has an influence on the structure; that is, whether the pure enantiomers are deposited one after another in series or they are deposited simultaneously via a racemic (50:50) mixture of the two enantiomers.   

 

 

 

Student Author(s): 

Disseler, Steven M.

Department(s):

Physics

Research Mentor(s): 

Paul Huffman/Physics

Title of Presentation:

Materials Development for PULSTAR Ultracold Neutron Source

The construction of a new Ultracold Neutron (UCN) source at the NC State PULSTAR reactor facility requires the implementation of several novel material systems to allow operation of the source in the extreme radiation environment of the reactor. Three important components tested during the course of this project are low thermal conductivity supports, a zircaloy thermal break, and thin-walled laser welded aluminum. The thermal conductivity of the supports, constructed from titanium by the Industrial and Systems Engineering department at NC State, is measured at several temperatures in an effort to determine the dimensions that provide sufficient strength while minimizing the heat load to the source. These thermal conductivity values are compared to theoretical values calculated using the SolidWorks platform. The zircaloy thermal break is constructed by explosion welding aluminum to a zirconium alloy and before being machined into a tube approximately 20 cm inner diameter. This tube is tested for its thermal conductivity, as well as the ability of the zircaloy-aluminum weld to remain leak-tight at cryogenic temperatures and high thermal gradients. Laser welding is used to join thin-walled aluminum parts that are not suitable for electron-beam welding. Several parameters, including laser power, filler wire use, and weld geometry are examined by standard metallographic techniques.  I will summarize the results of these studies and provide a brief description of the source itself.

 

 

Student Author(s): 

Gore, Kristen L.

Antczak, George

Brown, Tim D.

Wootten, Adrienne M.

Zheng, Jie

Department(s):

Statistics

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

William F. Hunt, Jr./Statistics

George Bridgers/NC Department of the Environment and Natural Resources--Division of Air Quality

Ryan Boyles/North Carolina State Climate Office

Title of Presentation:

Can Meteorologically Adjusted Ozone Air Quality Trends Identify the Impact of the Nitrogen Oxides Utility reductions? How Are Biogenic Effects Accounted for?

 

Inhalation of ground-level or tropospheric ozone can trigger a variety of health ailments, including chest pain, coughing, throat irritation, and congestion. Additionally, tropospheric ozone creates an increased risk of bronchitis, emphysema, and asthma. The ability to determine the impact of ozone precursor emission controls on ground-level ozone trends is complicated by the presence of meteorological and biogenic factors, which can enhance or hinder ozone formation. How does one know if emission controls are effective? The major precursors to ground-level ozone formation are volatile organic compounds (VOCs) and nitrogen oxides (NOx). The EPA Nitrogen Oxides State Implementation Plan Call (NOx SIP Call) was implemented in 2001 in an effort to mitigate the formation of ground-level ozone. Did it reduce ground level ozone? The purpose of this project was to build a regressive time series model that removes the effects of meteorology, autocorrelation, and seasonal trends. Additionally, we have implemented exploratory methods to gain insight into the biogenic effect and the sources of high ozone levels. Our dataset included ozone and meteorological data from the North Carolina Department of the Environment and Natural Resources, Maryland Departments of the Environment and the New Jersey Department of Environmental Protection, as well as the North Carolina State Climate Office. This data spans April through October of 1997 through 2006 for Maryland and Washington, D.C.; 1997 and 2005 for New Jersey; and January 1997 through October 2006 for North Carolina. As the result of our analysis, a series of models were combined with a filtered time series model, autoregressive, and back trajectory modeling to estimate the reduction in ground-level ozone over this ten-year period. These results suggest an improving trend in ozone concentrations over this time period in New Jersey, Maryland, and North Carolina.

 

 

 

Student Author(s): 

Greve, Benjamin K.

Department(s):

Chemistry

Research Mentor(s): 

Paul Maggard/Chemistry

Title of Presentation:

Surface Studies of Layered Perovskites for Designing a More Efficient Photocatalyst for the Production of Hydrogen from Solar Energy

 

In an attempt to design a more efficient photocatalyst for the reduction of water into hydrogen utilizing solar energy, the perovskite silver niobate (AgNbO3) was synthesized in varying amounts (1:1, 2:1, 3:1 molar ratio) of molten Na2SO4 flux.  This synthesis route was chosen because it was hypothesized that the preparation of silver niobate particles within a molten salt can change the surface features rendering the material active for hydrogen production.  Successful synthesis was confirmed by X-ray diffraction, and then the photocatalytic properties were explored.  The silver niobate particles prepared using this new synthesis route were found to be photocatalytically active in the presence of visible light, as hydrogen production was confirmed using gas chromatography.  The properties of this perovskite were then studied in an attempt to discover what features are responsible for photocatalysis.  The surface nano-/micro-level structure was characterized using scanning electron microscopy, and the electronic structure of the surface was probed using X-ray photoelectron spectroscopy.   

 

 

 

Student Author(s): 

Gromet, Donovan J.

Boboth, Zachary F.

Zimmer, Alisha J.

Scott, Mark S.

Hilarides, Eloise T.

Massey, Craig R.

Department(s):

Mathematics

Research Mentor(s): 

Kristin Duncan/Mathematics and Statistics, San Diego State University

Title of Presentation:

Weighting for Coverage Bias in Internet Surveys

Over the past decade, Internet surveys have become a popular method for collecting data about the general population.  In 2005, the Harris Poll published findings which claimed that 74% of the United States Population had access to the Internet somewhere.  While this number has steadily risen over recent years, bias still may be introduced if the population without Internet access is different from the Internet population in regards to the variables of interest.  In this research we studied whether Internet users that only have access to the Internet outside their home can be useful in reducing bias by assuming that they are more similar to those without Internet access than the Internet population as a whole.  This paper outlines several weighting adjustment schemes aimed at reducing coverage bias.  Data for this study was taken from the Computer and Internet Use Supplement of October 2003 administered by the Current Population Survey.  We evaluate the schemes based on overall accuracy by considering the reduction in bias for ten variables of interest and the variability of estimates from the schemes.  We find that several of our proposed schemes are successful in improving accuracy. 

 

 

 

Student Author(s): 

Hall, Kristen L.

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

Lonnie L. Leithold/Marine, Earth and Atmospheric Sciences

Title of Presentation:

Quantifying Changes in Clay Mineralogy on the Waipaoa Shelf, New Zealand Using FTIR (Fourier Transform Infrared Spectroscopy)

 

 

The purpose of this research project was to analyze cores samples from the continental shelf offshore from the Waipaoa River watershed in New Zealand to potentially record the effects of deforestation on land. The removal of forest cover has led to an increase in gully erosion and shallow land sliding in the watershed, with gully erosion currently being a dominant source of sediment to the river. The mixture of clay minerals in the sediments offshore may have changed as a result. Gullies erode into bedrock that is relatively rich in chlorite, whereas soils are built on volcanic ash that is chlorite-poor. This experiment compared percentages of minerals, especially chlorite in the core samples to determine changes in erosion processes acting on the Waipaoa watershed. Clay mineral standards mixed with potassium bromide (KBr) were analyzed on the Fourier Infrared Spectrometer separately and in mixtures, and then samples from the continental shelf were analyzed in the same manner. The spectrographs indicated distinct wavelengths by which the different minerals could be identified, and these were used to interpret results from core samples analyzed in the same manner. The results are consistent with known changes in erosion in the region over the past 4000 years, including higher erosion rates after humans deforested the area about 150 years ago.

 

 

 

Student Author(s): 

Hewitt, Andrew S.

Scott, Mary

Department(s):

Physics

Research Mentor(s): 

Laura I. Clarke/Physics

Title of Presentation:

Vapor Depositions of Organosilane Monolayers

Organosilane monolayers are widely used as surface modifiers, in order to change, for instance, the wetting properties of an oxide surface. Our lab studies molecular motion within self-assembled monolayers, including organosilanes.  The goal of my project was to find the optimal growing procedure for vapor deposition of dimethylalkyl silane monolayers onto fused silica (glass) substrates.  Important factors were reproducibility, the ability to obtain a tightly packed monolayer, and determining the pattern of molecules at low coverage (island formation or a uniform, dilute coverage).  For this poster, I'll focus on a test molecule, which consists of a silicon atom attached to four things: an 11 carbon-long alkyl chain with a polar top, two methyl groups, and one reactive chlorine. In the surface reaction, the Si-Cl bond reacts with the surface Si-OH to form a Si-O-Si link to the surface.  This orients the long C-11 chain roughly perpendicular to the surface. The molecules were vapor deposited at varying temperatures. Thickness and surface quality were measured using ellipsometry and contact angle measurements, and compared to expected values.  I will also present preliminary AFM (atomic force microscopy) results and results on dynamics within these films, from my collaborators.  I'll discuss our challenges in obtaining a monolayer of maximum density, and our approaches to understand this issue. I'll also discuss results on depositing molecules with a short alkyl chain (less than 11). I acknowledge funding from the Undergraduate Research Award and from the NSF NIRT project, Polar Molecules.  


 

 

Student Author(s): 

Hoffman, Torissa J.

Department(s):

Physical and Mathematical Sciences

Research Mentor(s): 

Jason Bochinski/Physics

Laura Clarke/Physics

Title of Presentation:

Morphology of Polycyclic Aromatic Hydrocarbons on Dust-like Surfaces

 

This research applies basic surface science to aerosol atmospheric chemistry in order to address the lifecycle of environmental contaminants associated with the burning of fossil fuels. Polycyclic aromatic hydrocarbons (PAHs) are cyclic organic molecules that are formed as a result of incomplete combustion of fossil fuels.  PAHs are environmental contaminants and have been known to be or, to decay to, carcinogenic or mutagenic products. We have the goal of studying how PAHs condense onto dust-like surfaces - in particular, whether they form a uniform coating or "bead up" on the surface of the dust, like water on a windshield. The manner in which the PAH arranges itself on the dust or soot may have a strong effect on the following: 1)its reactivity with ozone or uv-light, which can determine how long the PAH remains active in the environment; 2) the surface properties of the dust particles, which play a role in weather patterns and the formation of clouds; and 3) the health consequences of breathing PAH-contaminated dust. This work is inspired by a recent publication which showed non-uniform coating of another environmental contaminant (oleic acid) onto dust-like surfaces.  Many PAHs, such as fluoranthene and anthracene, have fluorescent properties. Furthermore, the emission properties of these compounds change dramatically when two molecules are close enough to interact. We have characterized the absorption and emission properties of fluoranthene and anthracene at different concentrations in solution, and for dilute and concentrated spin-coated samples on quartz (a model for dust). Next, we will vapor deposit the molecules onto surfaces, which will be a much closer approximation to the properties of the PAH-coated particles in the environment and allow us to determine if the molecules island or spread out uniformly.    

 

 

Student Author(s): 

Hornsby, Fawn

Department(s):

Statistics

Research Mentor(s): 

William Frederick Hunt Jr./Statistics 

Title of Presentation:

Impact of Wetlands on Water Quality

Headwater wetlands play a critical role both in terms of water quality, hydrology and habitat in North Carolina watersheds. This project aims to better understand the role these headwater systems have on improving water quality. Our data was collected by the NCDENR Water Division and consists of numerous variables measured at an upstream, a downstream, and, sometimes, a further downstream site. Some of the variables measured include differing forms of nitrogen, in addition to phosphorous, lead, copper, calcium, fecal coliform, and dissolved oxygen. Water quality parameters were sampled on a quarterly basis during six time periods: in April 2005, July 2005, October 2005, January 2006, April 2006 and July 2006 for each site. These time periods captured the dry season, wet season, and the transition period in between. Both parametric and nonparametric statistical tests were employed on paired observations of the data to see if there was a wetland impact on the water quality. Significant improvements were seen for dissolved oxygen in both the Piedmont and Coastal Plain, as well as for copper and lead in the Piedmont.    

 

 

 

Student Author(s): 

Howell, Julia K.

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

DelWayne R. Bohnenstiehl/Marine, Earth and Atmospheric Sciences

Title of Presentation:

Lava Dome Formation along a Superfast Overlapping Spreading Center, 28-32S on the East Pacific Rise

Deep-towed DSL-120 bathymetric data reveal the pattern of axial lava dome formation along a superfast spreading portion of the southern East Pacific Rise (EPR). The data span the overlapping limbs of the giant (~120 km offset) propagator system near 30S latitude. Domes are identified using a closed-contour algorithm, with auto- detections manually edited to account for the bathymetric gaps associated with the sonar system's nadir region and topographic shadowing. Along non-overlapping portions of the rift system with a full spreading rate of ~150 mm/yr, lava domes are rare and exhibit low relief relative to those imaged in equivalent datasets along the 17-19S latitude portions of the EPR [White et al., 2000 JGR]. As the axial depth increases and spreading rate decreases along the overlapping portion of the rift, the density of lava domes increases abruptly. Near-bottom photographic data show that pillow lava morphologies are restricted to these overlapping sections of the ridge crest. An increase in the abundance of lava domes near 2nd-order offsets also is observed. These observations are consistent with the eruption of lower effusion rate lavas near segment ends, where magma bodies become discontinuous and ephemeral.

 

 

 

Student Author(s): 

Igel, Matthew R.  

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

Nicholas Meskhidze/Marine, Earth and Atmospheric Sciences

Title of Presentation:

Effects of Aerosol on Shallow Marine Clouds in Bay of Bengal

With seasonal dust storms, considerable amounts of secondary organic aerosols (SOA) of biogenic origin and sharply rising anthropogenic emissions, the Indo-Gangetic Plain (IGP) is characterized by large concentration of chemically complex aerosols that may serve as cloud condensation nuclei (CCN). The IGP encompasses most of northern and eastern India, the populous parts of Pakistan, and virtually all of Bangladesh. Though many studies have focused on aerosols emanating from this region, few have examined the direct and indirect climatic effects of these aerosols, particularly once the aerosol laden air masses leave the Indian subcontinent and enter the Bay of Bengal (BoB). The BoB appears to be the ultimate destination of a considerable number of particles that can significantly modify properties of shallow marine clouds in this region. MODerate resolution Imaging Spectroradiometers (MODIS) aboard the Terra and Aqua platforms have been used in this study to quantify the effects of aerosols emanating from the IGP on shallow marine clouds in BoB. Particular attention has been given to pre- and post-monsoon seasons, when clouds should be more susceptible to increased CCN concentration. Results of our study show a consistent, sizable increase in MODIS retrieved aerosol optical depth (AOD) over the BoB that is in good agreement with the increase observed by the AERONET (AErosol RObotic NETwork) station at Kanpur over which, upwind aerosols must travel en route to the BoB. The effects of increased aerosol concentration on cloud effective radii and cloud optical thickness in the BoB are discussed. Potential long-term climatic effects for the case of continued/ increased pollutant emissions are also proposed.

 

 

 

Student Author(s): 

Jackson, Wilma C.

Department(s):

Statistics

Research Mentor(s): 

William F. Hunt, Jr./Statistics

Title of Presentation:

Improving Public Health Advisories for Forecasting Fine Particulate Matter for the Air Quality Index

 

 

Fine particulate matter is a significant pollutant that endangers human health. Small particles, 2.5 micrometers in diameter or less, penetrate further into the lungs of humans than larger particulates leading to increased cases of respiratory diseases and eventual death. Both annual mean and 24 hour National Ambient Air Quality Standards have been set for fine particulate matter (PM2.5). PM2.5 is one of five pollutants reported in the USEPA’s Air Quality Index. It is critically important that the current PM2.5 value be accurately forecasted so it can be reported to the public with an appropriate health advisory. My objective is to develop reliable forecasting regression models to serve as tools for predicting PM2.5. The regression models will take into account various meteorological parameters such as temperature, wind speed, wind direction, and yesterdays PM2.5 measurements. My client, the Maryland Department of Environment, provided all meteorological and fine particulate matter data. Analyses of selected particulate matter monitoring stations and meteorological sites in the state of Maryland have lead to discoveries of certain PM2.5 patterns. Trends show PM2.5 variations between winter and summer seasons as well as weekday and weekend periods. Various patterns, interaction terms, nonlinear curvature, and other possible confounders will be taken into account. The focus of this effort is to develop a model which predicts the midnight to midnight PM2.5 value by 10:00 a.m. in the morning. The prediction is made 14 hours before the midnight to midnight measurement is available. This approach is significantly more accurate than the prediction prepared the day before. It is necessary for this model to make use of the newest conditions in order to give the public the most reliable and current prediction possible.

 

 

 

 

Student Author(s): 

Jones, Stacy A.

Klein, Lauren A.

Rice, William “Jeff”

Department(s):

Statistics

Applied Mathematics

Political Science

Research Mentor(s): 

William F. Hunt Jr/Statistics

Tom Pace/USEPA

Josh Drukenbrod/USEPA

Title of Presentation:

Examining Crustal Matter: Resolving the Particulate Matter

Emission Inventory/Air Quality Discrepancy

 

 

The crustal matter found in fine particulate matter comes from the earth’s crust, fugitive dust, which consists of unpaved roads, agricultural tilling, construction, etc.  Crustal matter is affected by environmental factors such as season, wind speed, and day of the week, etc.  In 2001, the National Emissions Inventory estimated that the National total percentage of crustal matter to fine particulate matter (PM2.5) was estimated at 31.4%. The ratio of crustal matter in ambient air ranges from 5-10%.  This project focuses on the discrepancy in ambient air vs. emission inventory in the ratio of crustal matter to total fine particulate matter (PM2.5).  The ambient air measurements are taken from ambient air quality monitoring sites, located in both urban areas and in national parks and wilderness areas. We will discuss the model we developed to determine which variables affect this ratio.   The emissions inventory data is based upon engineering estimates from all types of sources such as fuel combustion, industrial processes, transportation and crustal material.  These emission inventories are the principal input into air quality models which are used to assess the air quality conditions across the United States.  Therefore, in order for the models to provide the most accurate predictions of future fine particulate matter levels, it is critically important that the emissions inventory data are consistent with the fractions of crustal material that are observed in measured data.  Analyzes will be done to better understand the impact of crustal matter on fine particulate matter air quality to ultimately gain information that will improve air quality in the United States.  Initial exploratory data analyzes will be run on a large data set to determine what environmental factors influence the ratio of the crustal matter to total fine particulate matter and course particulate matter.  

 

 

 

Student Author(s): 

Neely, Ryan R. III

Department(s):

Physics

Research Mentor(s): 

Hans Hallen/Physics

Title of Presentation:

Deep Ultraviolet Pre-resonance Raman Scatter of Ice and Its Implications for Climate Research

 

 

The Raman scattering of ice has been investigated near the deep ultraviolet electronic absorption. An optical parametric oscillator (OPO) was pumped by the third harmonic of a Nd:YAG laser, and the output frequency doubled to generate a tunable excitation beam in the 215-600 nm range. The light was scattered off a sample of ice at 0°C using the right angle geometry and coupled into a Spex Triplemate 1877 spectrometer.  As the excitation beam approached the absorption band of water, significant enhancement in the Raman signal was observed.  After normalizing for the non-resonant dipole absorption/radiation effects (frequency^4) and input laser power, the integrated intensities of the Raman spectra for excitation energies ranging from 2.9eV to 5.6eV were compared. The A term of the Raman scattering tensor, which describes the pre-resonant enhancement of the spectra, models the observed intensities as a function of incident beam energy. These findings suggest that application of pre-resonant or resonant Raman LIDAR could vastly improve spatial and temporal resolution of water vapor measurements in clouds. Such data could be used as a key element in the measurement of energy flow at the cloud-air interface. This energy problem is one of the major uncertainties in current global climate models.  


 

 

 

Student Author(s): 

Onori, John E.

Department(s):

Textile Engineering, Chemistry and Science

Research Mentor(s): 

Richard Kotek/Polymer and Color Chemistry

Title of Presentation:

Characterization of Cellulose in ED/KSCN

 

Cellulose is a natural polymer that is found in trees and plants. The problem with cellulose is that it does not dissolve in common solvents for example water and acetone. cupriethylenediamine is the only solvent used commercially for viscosity measurements of cellulose. The objective of this experiment is to dissolve cellulose in ethylenediamine and potassium thiocyanate salt system and take viscosity measurements of high molecular weight cellulose. Cellulose is dissolved in a 200 ml glass reactor equipped with a glass stirring rod which is hook up to a mechanical stirrer. Cold water and a condenser is used to prevent ethylenediamine from evaporating, constant nitrogen is used to prevent cellulose from degrading, and a heating coil held at a constant 60 degrees Celsius is used to aid in the dissolution process. 35/65 mixture of ED/KSCN is used as the solvent for dissolution. 1/8% of Tycell dissolves in ED/KSCN salt system in about 4 hours. Tycell is diluted to 1/2, 1/3, and 1/4 of the concentration before the measurements are taken. A 200 size Ubbelohde viscometer, constant temperature bath (held at 25oC) and a stop watch is used to determine the flow times of each solution. Intrinsic viscosity is calculated using a series of equations that included relative, specific, reduced, and inherent viscosities. Intrinsic viscosity was found by plotting reduced and inherent viscosity vs. cellulose concentration and extrapolating reduced and inherent viscosity back to the zero concentration. These two viscosities should meet at the same point. Intrinsic viscosity of Tycell was determined, both inherent and reduced viscosity agreed with each other.  

 

 

Student Author(s): 

Pagano, Lara E.

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s): 

Sandra E. Yuter/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

3D Forecast Model Predictability of Freezing Levels in

Portland, Oregon

 

 

The purpose of this research is to examine the accuracy of freezing level forecasts within several winter storms in the Portland, Oregon region. Over ten storms were examined for the 2005-2006 winter season with several different storm structures.  The regions around Portland have two mountain ranges, the Coastal mountains to the west and the Cascades to its east which modify storm structures as they move inland from the Pacific Ocean. The prediction of freezing (0 deg C) level is important since it determines the form of precipitation.  The freezing level can be observed, but 3D forecast models struggle to predict this feature over mountainous terrain.  This project used a vertically pointing MicroRain Radar (MRR) located in Portland to observe the freezing level heights within storms as they passed overhead.  A 3D regional mesoscale model was analyzed to determine the forecast freezing level for the same storms that were observed.  In comparing the observed and modeled freezing level heights, the degree of inconsistency between the observed and estimated data will indicate the storm characteristics that the 3D model couldn't clearly resolve. For example, during post warm frontal passages over the Portland region the freezing level heights are inconsistent between the observed and model forecasts.  After a warm front exits the area, the model tends to over predict the freezing level height by an average of 0.4 m. The variation between heights may be due to a bias produced by the model.  Determining the model’s strengths and weaknesses in the Portland area will provide information on which conditions the model has difficulty accurately representing within a storm. Results from this research will aid in diagnosing regional computer models used by forecasters.    

 

 

 

 

Student Author(s): 

Pope, Thomas C.

Department(s):

Physics

Research Mentor(s): 

John M. Blondin/Physics

Title of Presentation:

Bondi-Hoyle-Lyttleton Accretion

 

Bondi-Hoyle-Lyttleton accretion was first described in 1944 as an attempt to answer questions regarding the rate at which a point mass moving through a uniform gas cloud will gain material. Fryxell and Taam developed simulations in 2D to represent and study Bondi-Hoyle-Lyttleton accretion. Their study focused more specifically on the scenario of a gas cloud flowing past a black hole. Their simulation shows the gas forming a bow shock trailing the accretor which “flip-flops” from side to side. I wanted to know if this was due to the variable density of the gas and also if, by using a smaller accretor, the same results would be produced. With greater computing power available to me than was to Fryxell and Taam, I wanted to run their simulations at a very high resolution to find more accurate results. My first goal was to set up the same simulation they did, with all of the same parameters. The flip-flop appeared and graphs of the angular momentum were similar. I ran the simulation with a much smaller accreting object which would more closely simulate a black hole. Next I need to run the program again, this time with a uniform gas cloud to see the effects. I also want to use the new Yin-yang grid developed at NC State to try to see if the same results will appear in 3D.  

 

 

 

Student Author(s): 

Somers, Steven G.

Campbell, Amanda N.

Department(s):

Statistics

Research Mentor(s): 

William F. Hunt Jr./Statistics

Barry D. Nussbaum/Chief Statistician, USEPA

Title of Presentation:

Can Blood Lead Levels in Children be Reduced?

 

Lead exposure can be classified as either acute or chronic, with chronic being more common among children.  Exposure in children can have adverse affects on cognitive development.  Even very low levels of lead intake, previously thought to be harmless, have recently 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 was incorrect.  We performed regression analysis on the NC, NJ, and 2006 CA data sets and are attempting to predict EBLL as a function of environmental factors.  Through these possible regression trends, we hope to better inform the USEPA of areas with high EBLL so they will more knowledgeable as to which areas should be focused on for further research.  We have also produced a map that depicts the concentration of EBLL rates that highlights the rustbelt as the main area of concern for our nation, which disproves previous notions that the problem was mainly located in the southern states.  We will investigate other states such as AZ, CO, OH, IL, IN, PA and NY to determine the quality of the data.  Our final objective is to provide a more accurate data base than the one currently available for the CDC.  This research may be able to determine a major contributor to the current high EBLL in children.  Producing a more accurate model will help the government determine optimum control strategies to reduce blood lead levels 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.

 

 

Student Author(s): 

Stark, David A.

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s): 

Sandra E. Yuter/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

Characteristics of Mixed Precipitation Storms

 

Mixed precipitation storm events that include transitions among snow, sleet, freezing rain, and rain are examined using vertically-pointing METEKMicroRainRadar (MRR) data from two sites in the eastern United States. One site is located in the southern Appalachian Mountains at Poga Mountain, NC and another is located at Stony Brook, NY. The MRR measures the vertical profile of reflectivity and Doppler velocity at high time and spatial resolution. These characteristics make it ideal to observe short-term trends in the freezing level height which aids in determining whether the precipitation is liquid or frozen. Transitions among precipitation types are difficult to observe with scanning weather radar since shallow, near surface, cold and warm air layers often occur below the lowest level scanned. Accurately forecasting the timing of the onset of snow and changes in precipitation type is important for transportation agencies and decisions on school and business closures.  The main goal of this research is to characterize the structure of mixed precipitation events at Poga Mountain and Stony Brook to improve short-term forecasts. There were 18 mixed precipitation events at Poga Mountain during the 2006-2007and 2007-2008 winter seasons (November–April), and 11 mixed precipitation events during the 2007-2008 winter season. Transitions at Poga Mountain were mainly related to cold frontal passage with rain transitioning to snow. At Stony Brook, transitions were associated with warm frontal passage with snow transitioning to a mixture of sleet, freezing rain, and rain. The events at Poga Mountain had shallower snow layer heights, generally less than 2.5 km, compared to Stony Brook which had snow layer heights greater than 4.5 km. The more continuous and taller storm structures at Stony Brook made the trends in the freezing level height more visible than at Poga Mountain.

 

 

 

Student Author(s): 

Thomas, Diana E.

Department(s):

Meteorology

Research Mentor(s): 

Anantha Aiyyer/Meteorology

Title of Presentation:

Impact of Pacific Tropical Cyclones on Atmospheric

Predictability Over North America

 

This study examines tropical cyclones (TCs) in the Pacific Ocean and how they interact with the large scale atmospheric flow in the sub-tropics and mid-latitudes. In general, this interaction leads to flow perturbations that amplify and impact the predictability of weather over the United States. Since TC activity in the Pacific extends well into Northern Hemisphere winter, significant forecast errors during the cool season can be associated with incorrect representation of the TC induced interactions in numerical models. The primary objectives of this study are to (i) examine the anomalous upper-level flow perturbations induced by TC-environment interaction; and (ii) quantify the uncertainty in model predicted downstream flow pattern. The primary data for the study are the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data (henceforth referred to as observations) and output from a set of multi-ensemble numerical simulations (referred to as NCEP reforecasts). Additionally, TC tracks are obtained from the Joint Typhoon Warning Center.  Analysis of observations during times when a TC was present in the basin indicates that the TC outflow interacts with the upper-level mid-latitude jet stream. As a result, significant perturbations develop over North Pacific and subsequently propagate downstream over North America. These anomalous flow patterns can be understood in terms of Rossby wavepackets within the North Pacific waveguide. In addition to examining specific cases, storm-centered composites are created to elucidate common features of the flow evolution. In ongoing analysis, forecast errors over 12h to 360 h period are examined and metrics of predictability are being computed. Ensemble means and individual ensemble members from the reforecast data are being examined, the results of which will be presented at the symposium.

 

 

 

Student Author(s): 

Tyner, Bryce P.

Department(s):

Meteorology

Research Mentor(s): 

Gary Lackmann/Meteorology

Title of Presentation:

An Analysis into the Effectiveness of the NAM-211 Model for Forecasting Lake Effect Snow

 

 

An analysis into the validity for the North American Mesoscale (NAM) model, on an 80-km projection (hereafter NAM-211) for prediction of snowfall is important to operational forecasters. This project utilizes a case study of the January 29-30, 2007 lake effect snow event over Lake Erie to analyze the NAM-211’s ability to handle lake effect snow. The study compares NAM-211 forecast from 12z 28 January 2007 with the North American Regional Reanalysis (NARR) data provided by the National Centers for Environmental Prediction (NCEP). The project compares various variables important to lake effect snow forecasting including wind shear, upstream moisture transport, vertical temperature and moisture profiles, vertical air motion, and quantitative precipitation forecasts. Results of the study indicate that in spite of coarse grid spacing, the NAM-211 model overall accurately predicted important large-scale processes such as moisture transport, and synoptic-scale weather features influencing the event, and the relative wind shear. However, possibly due to poor grid spacing, inability to handle topographic effects, and the convective precipitation scheme, the model was more limited in predicting the small-scale processes important in pinning down exact precipitation amounts. Overall, the model forecast provided useful synoptic-scale guidance to meteorologists predicting this event.

 

 

Student Author(s): 

Watkins, Leslie G.

Department(s):

Physics

Research Mentor(s): 

Albert R. Young/Physics

Title of Presentation:

A Fast Data Acquisition System for Nuclear Physics

Data acquisition modules (DAQs) allow the capture and transfer of large volumes of information from analog signals produced by an experiment to digital data that can be stored and analyzed. We will test and develop a high rate, flash analog-to-digital converter (fADC) from CAEN Technologies, Inc, with the intention of more accurately measuring and recording the beta decay of Ne-19. This fADC will allow us to record the entire signal waveform produced by detector electronics, rather than a single data point, and fiber optic coupling will permit transfer of data to a PC at rates of 80 megabytes per second. Our ultimate goal is to develop a practical, working acquisition system with two fADCs, to test new versions of the firmware code, and to refine software required to process and store the waveform data. 

 

 

[ 2008 Undergraduate Research Symposium Main Page ]
 

 

Last modified April 2008 by Sharon E. Hunt, WordHunting