The 15th 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.

 

 

Student Author(s): 

Anderson, Bryan D.

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

James P. Hibbard/Structural Geology

Title of Presentation:

When Did the Atlantic Ocean Begin to Form?

 

 

The Holly Springs quarry exposes a shear zone marked by mylonitized volcanic - volcaniclastic rock of the Carolina terrane.  The shear zone is parallel to, and lies immediately within, the footwall of Jonesboro fault, the eastern boundary of the Triassic Deep River Basin.  The basin and the fault are known to be  manifestations of continental extension during the break up of Pangaea and formation of the modern Atlantic Ocean.  The close spatial relationship between the Jonesboro fault and the mylonite suggests that the mylonite could represent a deeper level, ductile segment of the Jonesboro fault, and thus, is related to the birth of the Atlantic Ocean. 

            The age of the mylonite has been previously determined as late Permian (255 +/- 2 m.y.).  The oldest strata deposited within the Deep River Basin are Carnian (227-221 m.y.).  If the mylonite represents a deeper segment of the Jonesboro fault, then the birth of the Atlantic Ocean would be 30 m.y. older than presently thought.  Alternatively, the mylonite may represent the final stages of the amalgamation of Pangaea (Alleghanian orogeny), known to occur at around 265 m.y.a. The kinematics of the final stages of the Alleghanian orogeny involve dextral strike-slip motion while kinematics of the Atlantic rifting event reflects a large component of normal dip-slip motion. By studying the kinematics of the mylonite and comparing them with regional geological data, the viability of theses hypotheses can be tested.

            Data collected from the quarry indicate that the mylonitic foliation records subhorizontal, dextral slip.  Northeast-trending Triassic faults do not typically show this sense of motion, but the mylonite is kinematically compatible with known Alleghanian faults in the region;  thus we suggest that the shear zone is related to the amalgamation of Pangaea rather than the birth of the Atlantic Ocean. 

 

 

 

 

Student Author(s): 

Baker, Adam K.

Rose, Joseph C.

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

Gary M. Lackmann/Marine, Earth and Atmospheric Sciences

Title of Presentation:

A Web-based Meteorological Teaching Tool:  Correlating Atmospheric Stability to Cloud Formation

 

 

Research in atmospheric stability conditions associated with various cloud types was undertaken in order to develop a visual and intuitive foundation for meteorological education.  The goal was to develop a website for use by undergraduate students, while also extending to pre-college students.  In order for users to gain an idea of how atmospheric instability affects cloud formation and what types of clouds are associated with each kind of instability, the website contains rendered cloud animations displayed in conjunction with observed temperature (stability) profiles.  In order to acquire representations of cloud formations, we (i) used a personal digital camcorder, (ii) utilized available digital camcorders from the D.H. Hill Library’s Digital Media Lab, (iii) worked with other students who had original footage, and (iv) worked with WRAL-TV to obtain webcam footage from atop their radio tower.  Videos were rendered to display footage in time-lapse format, and thus, in a format more suitable for observation and comprehension of cloud processes.  We plotted temperature and stability conditions using skew-T diagrams based on rawinsonde (weather balloon) data for the particular times and locations corresponding to where the cloud footage was taken, and displayed them alongside the time-lapse files on the website.  Descriptions were added to each appropriate cloud type or event.  The website will provide users with an easy way to conceptualize and visualize the concept of atmospheric instability, convective processes, and how both correlate with certain cloud formations. 

 

 

 

Student Author(s): 

Best, Kelly

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

Julia A. Clarke/Marine, Earth and Atmospheric Sciences

Title of Presentation:

A New Eocene Species of Coraciiformes from the Green River Formation

 

 

            Many of the fossil birds of the early Eocene (approximately 50 ma) Green River Formation of Wyoming have yet to be studied in detail, however they comprise an important assemblage. The avifauna, from deposits in an ancient and extensive North American lake system, represents one of the best of the period following the K-T boundary, where non-avian dinosaurs became extinct.

            Study of an extraordinarily preserved articulated avian skeleton lends support to a more complex historical geographic distribution for the group Coraciiformes. Living coraciiforms, or rollers, are medium-sized birds with colorful plumage and characteristic acrobatic flight, and are exclusively of the Old World. Excluding one fossil genus of the family Primobucconidae, the fossil parts of Coraciiformes are also only known from the Old World. Our fossil specimen collected in North America affirms pan-Atlantic distributions of this group in the Eocene. It also further challenges the hypothesis that coraciiforms originated in the Old World. 

            To evaluate our specimen’s relationships, we compared three fossil families (Primobucconidae, Eocoraciidae, Geranopteridae) and two extant families (Coraciidae, Brachypteraciidae) of Coraciiformes. A previously published cladistic character matrix comprising 36 characters was used to compare skeletal elements of our specimen to a total of 12 avain higher taxa. These data were used in a phylogenetic analysis to determine the new species’ relationships.

            Our specimen is supported as part of Coraciiformes by a skeletal feature, the presence of an elongate postorbital bar. It is excluded as part of derived Primobucconidae due to obvious size differences and differing skull morphology. It is diagnosable as a new species by skeletal element ratios that differ from other coraciiform taxa. 

 

 

 

Student Author(s): 

Conway, Robert E.

Hamilton, Daniel

Department(s):

Statistics

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

William F. Hunt, Jr./Statistics

Title of Presentation:

How Do Ambient Mercury Monitoring Sites Compare in Charlotte-Is there a Regional Pattern?

 

Mercury is a toxic pollutant that can cause adverse health effects in humans.  It is released into the atmosphere in several ways, most of which are involved in industrial processes. The mercury data set provided by North Carolina Department of Environment and Natural Resources (NCDENR) for Mecklenburg County North Carolina is expansive and complex and was collected using the Tekran Continuous Mercury Analyzer at four sites during 2002 and 2003.  The elemental (Hg0), total gaseous mercury (TGM) was collected in fifteen minute increments and the reactive gas (RGM) was collected over two hour increments.  The objective of this analysis is to use criteria provided by NCDENR for the species of ambient mercury collected to answer a number of questions: (1) determine seasonal, weekly, diurnal, and temporal patterns if they exist; (2) determine if there is site to site variability; (3) determine any interrelationship between the species of mercury and meteorological variables; and (4) identify possible point sources or source areas of high levels of mercury by conducting an in-depth examination of the wind data and trajectories. We will conclude this project with a statistical protocol to present to NCDENR for future analyses and presentations of these types of data.

 

 

 

 

Student Author(s): 

de Deugd, Casey M.

Department(s):

Physics

Research Mentor(s): 

Laura Clarke/Physics

Title of Presentation:

Heterogeneous Monolayers of Silane Based Molecules

 

 

Self-assembled monolayers have been studied in a variety of disciplines because they are well-defined, stable molecular systems. The development and characterization of amine-terminated mixed monolayers of silane-based molecules is presented. In developing a procedure for depositing an amine-terminated molecule 3-aminopropyltrimethoxysilane (3APS) in combination with its non-amine terminated counterpart Pentyltrichlorosilane (PTS), I was also able to observe some hints of amine self-catalysis and the catalytic effects it has on the non-amine molecule. Subsequently, I implemented a two phase "back-filling" procedure that enables me to create an organized surface of 3APS and PTS. The purpose of changing the homogeneity of the surface chemistry was to utilize the amine terminated groups as attachment sites for fluorescent probes without creating an overly dense environment. By establishing a mixed monolayer of molecules, some with amine terminated functional groups and some without, I was be able to isolate the fluorescent groups so that they were not interacting with each other and instead to probe their interactions with the environment. Characterization methods of these molecular systems include contact angle, ellipsometry, and UV-vis spectroscopy.

 

 

 

 

Student Author(s): 

Diaz, Michael L.

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s): 

Sethu Raman/Marine, Earth, and Atmospheric Sciences

Ryan Boyles/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

A Statistical Quality Control Scheme

for the NC Environment and Climate Observing Network

 

 

Accurate meteorological data are required for weather forecasts and management of utility loads, water resources, and other environmental applications. Inaccurate data within a station’s climate record will make it nearly impossible to create an accurate climatology for a specific station. A system which would eliminate past corrupted data and issue future alerts when a sensor may be reporting incorrect data will help ensure a more accurate dataset for the North Carolina Environment and Climate Observing Network (ECONet).

            A data quality control system is tested which uses statistics calculated from a station’s own past record to construct a tolerance range within which the overwhelming majority of observations will fall. By flagging the few data points which fall outside of this range, this technique will help identify suspicious data and allow someone to subjectively determine if the flagged data is reasonable.

            The results of this study demonstrate that the median for a specific parameter plus or minus a multiplier of the standard deviation will yield a tolerance range which can accomplish this task with a minimal number of false warnings (less than five per year). However, each parameter requires a different multiplication factor. Parameters which remain relatively consistent will need a smaller tolerance range than ones which have large hour to hour variations. For example, soil temperature may need a multiplier of only 2.7 whereas wind speed may need one as high as 4.4.

            When this quality control scheme is fully implemented, it will ensure a more accurate climatic dataset for the NC ECONet stations.

 

 

 

Student Author(s): 

Evans, Courtney F.

Department(s):

Physics

Research Mentor(s): 

Laura I. Clarke/Physics

Title of Presentation:

Growth of Carboxylic Acid Monolayers

 

 

In our laboratory, monolayer film growth is utilized to create molecules with an axis perpendicular to the surface so we can study how things rotate around the axis.  Spontaneous self-assembled monolayers can be formed on a variety of substrates with diverse molecules.  Past experiments in our laboratory have utilized silane chemistry and a silica substrate.  Monolayers were formed, however, less than optimal results were observed.  In principle, each silane molecule has three OH feet spanning 20 A2.  Since the hydroxyl density on silica is only 1 OH per 20A2, only one foot on average was able to attach to the substrate.  Presumably, other feet bind with neighboring molecules.  Other factors, such as dependence of film growth on the concentration of H2O in the solution, also provided challenges such as sub monolayer growth or vertical polymerization.  Because of these impeding factors with silane chemistry and the lack of a vertical axis, other monolayers were researched.  It was decided that attaching carboxylic acid to a fused silica surface through chemisorption might yield monolayers with better ordering; however, the strength of the mechanism of the surface attachment is unknown.  I experimented with growing stearic acid monolayers on glass and aluminum by toluene, hexadecane, and acetonitrile solution depositions.  I also grew monolayers of acetic acid and stearic acid on aluminum and glass by vapor depositions.  If strong attachments of these monolayers are proven, this will provide a good base for eventually attaching our rotors, and also further researching the possibilities of monolayer uses within oxidation and corrosion protection.

 

 

 

 

Student Author(s): 

Grabowski, Kathryn E.

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s): 

Anita McCullouch/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

Distribution of Phytoplankton Populations of the Galapagos Islands

 

 

Phytoplankton populations play a very important role as the basis of food chains for the rest of the species inhabiting the oceans.  This study examines the phytoplankton species and their varied populations associated with the major currents that are present around the Galapagos Islands.  Phytoplankton samples were taken during several seasons from the different major current systems surrounding the Galapagos.  Samples were then analyzed to determine phytoplankton species and populations based on current types.  The samples have shown a correlation between unique phytoplankton species specific currents that were influenced by temperature and nutrient supply.  Also, the populations of phytoplankton are influenced by the major current types.  These correlations will help in analyzing how phytoplankton populations will change due to issues such as global warming and El Nino.  Changes in phytoplankton populations could affect the higher trophic level organisms like zooplankton leading to drastic effects for countries whose economy is dependent on the fishing industry. 

 

 

 

Student Author(s): 

Hare, Brian C.

Department(s):

Statistics

Research Mentor(s): 

William F. Hunt, Jr./Statistics

Title of Presentation:

Alternative Emission Standards - Making Better Use of Continuous Data

 

 

Why do we need emission standards?  We need them to prevent industries from producing excessive amounts of harmful chemicals. There is little disagreement that this need exists, but the methods used to implement such a standard are subject to debate. If the emissions from a source are tested monthly and one observation exceeds a certain limit, it may be reasonable to believe that source is polluting more than it is supposed to. However, if data is taken hourly, there will likely be a few hours that exceed the limit due to variation alone. These do not necessarily show that the source is in violation, and should not result in fines or punishments for the industry. I investigated various ways to utilize continuous data with the understanding that it is insignificant if a few hours in a year plot too high. I worked with data of nitric oxide from different sources with different intervals between measurements that was provided by my client, Gary McCutchen, from RTP Environmental, Inc. The data from each source visibly changed through time, showing increases and decreases as the company changed its production and processes. Given these changes over time, a method to identify whether the source has too much pollution must be able to represent the current emissions of the source with little consideration for outliers and how the data used to be. I explored different methods with the various datasets, and found the most success with moving averages. If used, the averaging time should be long enough to reduce chance variation, but short enough to avoid mixing with old data. A moving average of about six to eight observations usually takes care of both problems.

 

 

 

 

Student Author(s): 

Holland, Emily L.

Department(s):

Statistics

Research Mentor(s): 

William F. Hunt, Jr./Statistics

Title of Presentation:

Using Statistical Methods to Examine Changes in the Toxic Release Inventory

 

 

The USEPA releases Toxic Release Inventory (TRI) data for public access.  Since the USEPA began collecting data (which includes air, water, and ground emissions from industrial facilities with more than ten employees) in 1988, it appears that the total toxic release has decreased.  However, there are many factors to consider when determining the significance of this decrease.  For example, the removal and addition of chemicals required to report to TRI, must be taken into consideration.  Further, by examining industry type and state/territory, different trends and outliers are easily observed.  By using classical statistics methods, obvious patterns and outliers in the TRI data can be found in different states and industries.  Simple regression was used to predict industry trends, and unusual years and observations were identified. The states and industries with abnormalities were analyzed to determine if these changes were substantial, a transcription error, a change in the listed TRI chemicals, or something else.  Adding dummy variables to the regression analysis of industry trends to take into account these changes in the TRI data were used in order to improve the regression.  A focused analysis was conducted for specific industries in specific states to pinpoint where certain industries were making significant decreases in the release of toxins.  The petroleum industry was examined in large oil producing and refining states such as Texas, Louisiana, and New Jersey while mining industries were examined in Alaska, Nevada, and Utah, the top three released mining emissions states.

 

 

 

 

Student Author(s): 

Hornsby, Fawn

Jackson, Wilma

Larsen, Caroline

O’Donnell, Roberta

Department(s):

Statistics

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

William F. Hunt, Jr./Statistics

Title of Presentation:

How Do Ambient Air Pollution Mercury Levels Compare Between Elizabeth and New Brunswick, NJ?

 

 

Mercury is a toxic pollutant that can cause adverse health effects in humans through bioaccumulation in fish.  It is released into the atmosphere in several ways, most of which involve industrial processes.  From the atmosphere, mercury enters the water via wet and dry deposition where it bio-accumulates in fish.  Because of this concern, mercury air monitoring sites were established in Elizabeth and New Brunswick, NJ.   The Tekran Continuous Mercury Analyzer was used to measure elemental, particulate and reactive gas mercury over a two-year period.  Initially, we focused on three months of this data; June, July, and August 2005 at the Elizabeth site.  The data were examined to find the seasonal, weekly and diurnal patterns and the statistical distributions of each form of mercury. The instrument collects data every other hour and has a random start time after midnight.  It collects 12 five minute consecutive measurements for elemental mercury and hourly measurements for particulate and reactive gas mercury.  The NJDEP’s data quality standards were applied.  Only days with 50% data completeness were used. The data were divided up into three-hour time blocks; the midpoint of the hourly data was used to assign the hourly measurements to the eight three hour time blocks.  Diurnal patterns were found for each form and each form appears to be log-normally distributed.  By looking at both sets of data over the entire two year period, seasonal patterns seem to be similar at both sites.  The correlations between the sites are also examined to determine possible regional and local patterns.  Additionally, we have utilized associated meteorological data to identify possible sources of the mercury through the examination of wind data and trajectories in addition to examining the highest concentrations of mercury data compared with wind speed and direction.

 

 

 

 

Student Author(s): 

Inge, D. Brandon

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

Gary M. Lackmann/Marine, Earth and Atmospheric Sciences

Title of Presentation:

A Summation and Analysis of Tropical Cyclone Gaston of 2004

 

 

This paper contains a detailed summation of the post-landfall life and weather associated with the tropical cyclone Gaston of late August 2004.  Gaston’s spawned tornadoes in southeastern Virginia and its contribution to extremely high rainfall totals in Richmond, VA, are the primary foci of this paper.

            To date, specific atmospheric and geographic influences that caused record-level rainfall and subsequent flooding are not well understood.  Possible influences of diabatic processes, cold frontal presence, Chesapeake Bay location and moisture influx, along with storm-relative helicity values, which aided in the anticipation of hurricane-spawned tornadoes, were analyzed.  The analyses of these variables provide insight into the role that each played.  It does not, however, lead to a determination of direct causal effect, but rather to the hypothesis that moisture influxes from the Chesapeake Bay, along with solar radiational heating, were likely factors contributing to the heavy localized Richmond-area precipitation.

 

 

 

Student Author(s): 

Kolluru, Subha R.

Department(s):

Statistics

Research Mentor(s): 

Marcia L. Gumpertz/Statistics

Title of Presentation:

Use of a Balanced Incomplete Block Design to Ensure Confidentiality and Estimate Incidence of Cheating in Statistics Classes at NCSU

 

 

Concerns have arisen among professors and instructors at North Carolina State University regarding possible cheating taking place in Statistics courses.  The incidence of cheating could be estimated by taking a survey including specific questions about cheating.  Although this method provides exact responses, it involves asking sensitive questions that respondents may feel uncomfortable answering honestly.  Other methods might reduce respondents’ anxiety and obtain more truthful answers.  In this study we compare a method based on the Balanced Incomplete Block Design (BIBD) to the direct question approach.  This study answers three specific questions about cheating.  Combining these with other innocuous questions may decrease tension of the respondents and therefore eliminate some response bias.  In addition, respondents only report the total number of questions which are true, so that specific answers to individual questions are kept confidential.  Statistical methods can then be implemented to recover information about the sensitive questions.  In particular, the Balanced Incomplete Block Design (BIBD) provides structure for combining sensitive with innocuous questions in a way that is efficient for recovering information.  This poster will estimate the prevalence of cheating and observe any differences in the estimates between the two methods.

 

 

 

 

Student Author(s): 

Larsen, Caroline

Savage, Crosby

Silverman, Morgan

Hill, Christopher

Department(s):

Physics

Research Mentor(s): 

Thomas P. Pearl/Physics

Title of Presentation:

The Comparison of Gravity Waves in the Atmosphere of Mars using Different Froude Numbers in 2D Simulations with a GFDM

 

Chiral molecules (molecules with non-superimposable mirror images) are important for many biological and chemical processes.  These molecules can impart chirality on achiral surfaces.  The formation of these chiral domains has been proposed as a key feature in the effectiveness of enantioselective heterogeneous catalysts (only allows certain types of reactions).  We present research on the behavior of tartaric acid on a Ag(111) surface using low energy electron

diffraction (LEED) and low temperature scanning tunneling microscopy

(STM) to observe whether this molecule imprints its stereochemistry.

Tartaric acid (C4H6O6) contains two chiral centers on the two middle carbon

atoms in the four carbon chain.  The Ag(111) surface is an achiral surface which exhibits an electronic surface state where it is possible to image electron waves scattering off defects in the crystal.

            Our research shows that (R,R) tartaric acid forms an ordered, commensurate structure on Ag(111).  At 77 K, scanning tunneling microscopy (STM) data shows that the tartaric acid likes to bond to the silver near step edges, where the silver surface steps down one atomic layer or more.   In the near future, we plan to also investigate how the surface state of silver affects where the tartaric acid decides to bond to the surface.  We would also like to dose the other chiral pair of tartaric acid (S,S) onto Ag(111) to see if there is any difference in the way the molecule will adsorb.

 

 

 

 

Student Author(s): 

Lakhani, Amit M.

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

Yuh-Lang Lin/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

Adsorption of Tartaric Acid on Ag(111)

 

 

Gravity waves are atmospheric wave motions where buoyancy force acts as the restoring force. On Mars, topographic forcings, such as mountains, valleys, and craters, produce higher amplitude gravity waves than the waves observed over mountains on Earth due to higher mountains and deeper valleys on the Mars surface. The NCSU-GFDM (Geophysical Fluid Dynamics Model; Lin and Wang 1996 JAS) was used to simulate wave activity in the Mars atmosphere. In the simulations, Froude numbers of 1.2, 0.9, 0.6, and 0.3 were used to simulate flow over a single bell-shaped mountain of 2.5 km. Based on Lin and Wang’s (1996) experiments on the Earth atmosphere, we hypothesize that these Froude numbers will generate four different flow regimes. Note that the Froude number is defined as U/Nh, where U is the basic wind speed, N the Brunt-Vaisala frequency, and h the mountain height. The Froude numbers of 1.2, 0.9, 0.6, and 0.3 in our experiments will be varied by varying the U wind speed to be 21 m/s, 15.75 m/s, 10.5 m/s, and 5.25 m/s, respectively. Output from the four model runs is still being analyzed but the lower Froude-number flows are expected to show more blocking with the presence of severe downslope winds and hydraulic jumps, while the higher Froude-number flows are expected to show more upward propagating gravity waves. Model output is examined using plots of horizontal velocity (m/s), vertical velocity (m/s), potential temperature (K), and perturbation pressure (Pa). Of particular importance are the plots of potential temperature and vertical velocity, which exemplify the magnitude and upward propagating characteristics of the observed waves. The four comparisons of the varying Froude numbers will further enable the study and classification of the atmospheric dynamics of the Mars atmosphere.

 

 

 

 

Student Author(s): 

McGuire, John A.

Pearson, Ray D.

Department(s):

Physical And Mathematical Sciences

Research Mentor(s): 

Cynthia Cudaback/Oceanography

Title of Presentation:

Ocean Literacy of Undergraduate Students Entering an Introductory Course in Oceanography

 

 

Professors have wondered what interests students in oceanography, what they know of the impact humans have on it, and their knowledge of different aspects of oceanography. We investigated these is by analyzing surveys in which students answered thirteen questions, ranging from short answer to paragraph responses, about their knowledge of oceanography and rationale for taking an introductory course in oceanography. Each question was scored in regard to accuracy of the answer and, if applicable, the reasoning given in the answer, on a score of 0 to 2 developed by Dr. Cudaback. We have found that many students enroll in this course to learn more about the oceanic biology, the mechanics of the ocean itself (such as tides, currents), and learning more of the link between terrestrial and marine life. It is hoped that it will be shown that students improved their ocean literacy when they take the exit surveys upon completion of the course.

 

 

 

 

Student Author(s): 

Orelien, Katina G.

Raisanen, Kristin M.

Department(s):

Statistics

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

William F. Hunt, Jr./Statistics

Title of Presentation:

Do You Know the Quality of the Air You Are Breathing?

 

 

Do you know the quality of the air you are breathing? This research project deals with the AirNow and Air Quality System (AQS) databases, both of which contain air quality data.  The AirNow database contains air quality data that is used for daily air quality index forecasts. The AQS database contains air quality data that has been verified and corrected by the federal government and is the method used to compare with the National Ambient Air Quality Standards for fine particulate matter.  Discrepancies were found in the concentrations reported to AirNow and AQS. On some occasions the AirNow database reported 2-3 AQI levels above or below what was reported to the AQS database.  The various locations and seasons of where and when these discrepancies in the AirNow occurred were identified.  These findings suggest a difference in the way the AirNow values and AQS values in the various states are being reported to the EPA.  Statistical analyses  will be done to find the best method of sending a warning to the individual states that are not providing the EPA with correct air quality index values within the AirNow database.  The purpose of this project is to provide the public with reliable air quality information so that they can make the appropriate decisions regarding their daily activity and health.  Since there is no alarm to signal the states that are not getting the AirNow values correct before they send these values to the EPA, we are developing an early warning system.  Unless the air quality values are properly corrected, many U.S residents can be misinformed about the quality of the air they are breathing and this could adversely affect their health.

 

 

 

 

Student Author(s): 

Peak, Kelly L.

Department(s):

Marine, Earth and Atmospheric Sciences

Research Mentor(s): 

Edward Stoddard/Marine, Earth and Atmospheric Sciences

Title of Presentation:

Is There a Correlation Between Bedrock Geology and Radon in Indoor Air or Groundwater in Wake County, NC?

 

 

Wake County Environmental Services is conducting a three-phase study in association with the North Carolina Radiation Protection Section to investigate the relationship between bedrock geology and radon in indoor air and groundwater.  The County was divided into ten strata according to bedrock geology, emphasizing granitic plutons and other rock types believed to contribute to high radon levels.  Using a stratified sampling design, homes were selected randomly within each stratum, ensuring inclusion of all ten strata.  Data were collected using a radon indoor air test kit and groundwater samples from homes with private domestic wells.  Of the 800 homes targeted in the two completed phases, data have been collected from over 300 homes.  Preliminary statistical analyses have been completed.  While there are many high readings of radon in air (over 4.0 pCi/L by EPA guidelines) and radon in water (over 10,000 pCi/L), the averages in each stratum and overall in the county are not high.  Highest maximum radon values are observed in the Rolesville batholith stratum and adjacent strata on the east and west, in the Falls leucogneiss, and in the Crabtree terrane.  Despite broad conclusions that may be made from the preliminary results, the overall complexity of the geology and the role of other factors require more sophisticated statistical modeling.  This modeling, along with the third phase of data collection will provide valuable information and guide future policies for Wake County. 

 

 

 

Student Author(s): 

Phillips, Katherine C.

Department(s):

Physics

Research Mentor(s): 

Karen Daniels/Physics

Title of Presentation:

Size Segregation of Granular Materials Under Shear

 

 

When granular materials of different sizes are sheared, the particles segregate by size because the smaller particles can fall through the spaces created as the larger particles move sideways.  Quantitative predictions for the rates and patterns of particle segregation are largely unknown but are important to many industrial and natural processes.  For instance, rock avalanches are composed of varying-size particles.  As the avalanche runs downhill, particles move with a velocity parallel to the surface, but they can also move perpendicular to the surface due to the segregating effect of shear. 

            We conduct experiments on continuously sheared mixtures of different size particles and observe their motion near a vertical boundary separating the two sizes. We find that larger size ratios mix and segregate faster than small size ratios. A mathematical model of shear segregation predicts that a lens-shaped mixing region will form during this process, and we seek to create conditions that allow for this mixing pattern to be observed.

 

 

 

 

Student Author(s): 

Pimputkar, Kaustubh R.

Bharath, Satyaveda C.

Department(s):

Physics

Research Mentor(s): 

Thomas P. Pearl/Physics

Title of Presentation:

Preparation and Characterization of Atomically Flat Lithium Niobate Surfaces

 

 

Low-energy electron diffraction (LEED) and atomic force microscopy (AFM) were used to characterize the surface of lithium niobate (LN), a polarizable ceramic material, for use in molecule deposition studies. First, the LN is cleaned in an ultrasonic bath using acetone then methanol.  To further remove impurities, the sample is placed in an ambient surface (1273 K).  This step generates an atomically flat surface as verified by AFM and LEED, which is receptive to the deposition of molecules.  However, due to the high surface polarization (i.e. affinity for attracting charged particles) a passivation layer of chloro-trimethyl silane (TMSCl) can be deposited.  This deposition is done on the LN surface, upon removing the LN sample from the ambient surface, using a vapor technique.  By applying a passivation layer, the deterioration of the LN surface is decelerated without changing the surface chemistry. Potentially, when we obtain an in-depth understanding of the surface chemistry and the surface characteristics, we will be able to better manipulate and image molecules (specifically liquid crystals) deposited on the surface.

 

 

 

 

Student Author(s): 

Reising, Sarah E.

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s): 

Edward F. Stoddard/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

A Petrographic and Geochemical Study of a Quartz-Normative Diabase Dike in the Eastern Piedmont

 

 

The Piedmont is riddled with Early Mesozoic dikes formed during the break-up of the supercontinent of Pangaea.  While the most typical diabase is olivine-normative, this study focuses on the petrology, origin, and crystallization history of an unusually wide, quartz-normative diabase that has been mapped from Johnston Co., NC into VA.  Studying the dike will contribute to ongoing research concerning North Carolina's geologic history.  The diabase primarily consists of interlocking crystals of plagioclase feldspar, augite, and pigeonite, with minor amounts of Fe-Ti oxide minerals, and intergrown quartz and K-feldspar.  Samples taken across the width of the dike show changes in modal mineralogy and texture, including an increase in grain size, from the dike's margins toward the center.  These characteristics imply slower crystallization at the center of the dike and possible rafting of early-formed phenocrysts of Ca-rich plagioclase.  To determine the origin of the magma that formed the dike, the concentrations of rare-earth and other trace elements  in the diabase are normalized to presumed primordial values to create geochemical discrimination ("spider") diagrams.  Spider diagram patterns may be compared to those of igneous rocks from known tectonic provinces such as basalts formed in ocean islands, mid-ocean ridges, and continental flood basalt plateaus.  In addition to whole-rock chemical composition, the compositions of individual minerals in the diabase are needed in order to model the crystallization of the magma.  Mineral analyses done by electron microprobe have revealed the coexistence of three distinct varieties of pyroxene, allowing determination of the conditions of crystallization.  Additional analytical work is in progress, and should reveal more about the origin and evolution of the magma, and perhaps its implications for the rifting of Pangaea and the birth of the Atlantic Ocean basin.

 

 

 

 

Student Author(s): 

Ribeill, Guilhem J.

Department(s):

Physics

Research Mentor(s): 

Keith Weninger/Physics

Title of Presentation:

Fibrinogen Adsorption on Nanocrystalline Diamond and PEG Surfaces

 

 

Biological compatability of materials is critically dependent on their resistance to adsorption by immune system proteins. The most important of these is Fibrinogen, which is responsible for the activation of the body's clotting mechanism. Fluoresence microscopy was used to determine the amount of adsorption by dye-labled fibrinogen on PEG and nanocrystalline CVD diamond. Various concentrations were applied to the surfaces, and after a wash, the total bulk fluorescence was measured through both normal and total internal reflection microscopy. PEG is already used to prevent adsorption, and nanocrystalline diamond is a surface that shows great promise in the creation of biologically inert materials.

 

 

 

 

Student Author(s): 

Roberts, Wesley A.

Department(s):

Aerospace Engineering

Research Mentor(s): 

Laura Clarke/Physics

Title of Presentation:

Conduction of Electrospun Fibers Containing Carbon Nanotubes Through Insulating Polymer

 

 

Polymer-carbon nanotube nanocomposites show great technological promise due to their enhanced conductivity and strength.  Whereas mechanical properties are often the primary focus for forming nanocomposites, a byproduct of nanotube doping is increased conductivity due to the highly conductive carbon.  We study conductance in electrospun fibers of insulating polymer doped with carbon nanotubes.  Furthermore by examining conductivity, correlations between microscopic and macroscopic properties can be determined and mechanical strength can be predicted by measuring the conductivity of the nanotube doped polymer instead of using invasive or destructive properties testing.

 

 

 

 

Student Author(s): 

Robles, Francisco

Department(s):

Physics

Research Mentor(s): 

John M. Blondin/Physics

Kazimierz Borkowski/Physics

Title of Presentation:

Producing the 'Jets' of the Cassiopeia A SNR with a Spherical Supernova

 

 

The one–million Chandra X-Ray Observer image of the supernova remnant of Cassiopeia A shows a clear jet-like structure extending beyond the main shell of the blast-wave in the upper left and a possible counter jet in the opposite direction. Here we show that the morphology of Cas A is consistent with a spherically-symmetric explosion evolving into a slightly axisymmetric circumstellar medium as well as a mildly asymmetric explosion enveloping into a spherical CSM. Following up on the original models of Blondin, Lundqvistand, Chavalier (1996), we use a 2D and 3D hydro-dynamical simulations to show that young, ejecta-driven SNRs with relatively mild axisymmetry(density contrast between pole and equator of order a few in either the ejectaor CSM) can produce the extended features similar to the observe “jets” in Cas A. We use these models to show that shocked ejecta can be reaccelerated in the vicinity of the “jets” to produce local velocities that exceed R/t, i.e., gas that appears to be un decelerated was in fact slowed down by the reverse shock and then reaccelerated. This has the added result that material originating deep in the SN ejecta can end up at very large distances along the “jets” as compared to the locations in the remnant.

 

 

 

Student Author(s): 

Rogers, Charles R.

Department(s):

Mathematics

Research Mentor(s): 

Moody T. Chu/Mathematics

Title of Presentation:

Quadratic Inverse Eigenvalue Problems

 

 

The Quadratic Eigenvalue Problem (QEP) has received a great deal of attention because its formation has frequently arisen in several different disciplines, including applied and fluid mechanics, electrical oscillation, seismic tomography, damage detection, and finite-element model updating in aerospace and automobile industries.  The scope of activities and range of application strongly signifies the importance of the Quadratic Inverse Eigenvalue Problem (QIEP).  The concern in the direct QEP is expressing dynamical behavior in terms of physical parameters versus the QIEP’s concern of expressing physical parameters in terms of dynamical its observed or expected behavior.  These physical parameters include, but are not limited to mass, resistance, spring constants, capacitance, damping, inductance, length, and elasticity.  In particular, the QIEP aims to find three symmetric matrices, known as the mass, the damping and the stiffness matrices, correspondingly such that they satisfy the deliberate data and are contiguous to the specified analytical matrices.  With the aid of mathematical computer software, focus was placed on the QEP by exploring its dynamic behavior when the physical parameters are manually controlled.  Consequently, appealing results were obtained graphically that gave direction for the present QIEP focused research. A broad-spectrum code is currently being developed that will allow users to acquire affirmative answers on whether their specifically configured systems can be built and, if yes, how the parameters should be valued.  As progression for developing a successful code for the QIEP slowly progresses, it has been found that the inverse problem is just as significant as the direct problem in application, yet more intricate.  Ultimately, a code will be developed that permits civilization to cost-effectively build and test computer and VLSI chips.

 

 

 

 

Student Author(s): 

Rose, Aaron

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s): 

Ping-Tung Shaw/Marine, Earth, and Atmospheric Sciences

Title of Presentation:

Internal Wave Generation over the Continental Margin in the South China Sea

 

 

Satellite imagery of the South China Sea displays internal wave trains that form as a result of tidal forcing over bottom topography. Internal wave generation by semi-diurnal tides across a continental slope with varying depths of the thermocline is studied here. Internal waves were generated using a nonhydrostatic primitive equation model written in MATLAB. Tidal currents crossing the shelf break in each tidal cycle produce depressions in the density surface. These depressions then intensify into tidal bores in the density surfaces which produce internal wave trains propagating away from the shelf break. The structure, speed, intensity, and number of wave crests formed depend on the depth of the thermocline. For the case of a deep thermocline, an elevation wave was formed every tidal cycle, propagating towards the coast quickly and resulting in a larger amplitude wave train. In the case of a shallow thermocline, a depression wave was generated in each tidal cycle, propagating towards the coast at a slower speed. In the latter case, an internal wave train was not generated at the end of the first tidal cycle.

 

 

 

Student Author(s): 

Savage, L. Crosby, III

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s): 

Yuh-Lang Lin/Atmospheric Science

Title of Presentation:

Idealized Simulations of Low Froude Number Flow Over Martian Mountains

 

 

This study examines the effect of varying Froude numbers on flow around idealized Martian mountains. A similar study has been done using an Earth numerical model, where lee side vortices as well as gravity waves were shown to develop in low Froude flow. To simulate the Martian atmosphere the NCSU-GFDM numerical model was adapted using NASA observed constants and variables. Four separate cases were run with varying Froude numbers of 1.2, .9, .6, and .3. In each of these cases both the Brunt-Vaisala frequency and height of the mountain were held constant as the speed of the basic flow was changed. Results of the simulations were similar to those found on Earth with higher Froude flow creating less blocking and upward propagating gravity waves and lower Froude flow creating lee vortices.

 

 

 

 

Student Author(s): 

Scott, Mary C.

Department(s):

Physics

Research Mentor(s): 

Jason Bochinski/Physics

Title of Presentation:

Characterizing the Rotational Motion of Coumarin using Polarized Fluorescence Measurements

 

 

Understanding molecular motion is an important area of nanoscale science.  One type of motion that molecules can undergo is rotational motion. Coumarin is predicted to undergo hindered rotational motion when attached to a monolayer silane film.  Since coumarin is a fluorophore, its movement can be detected via temperature-dependent polarized spectroscopy.  When such a molecule absorbs pure linearly-polarized light, if it can rotate before relaxing from its excited state, it will emit light with a different polarization orientation. Measurement and comparison of these different polarization components is the key behind the technique of fluorescence anisotropy.  Using such fluorescence anisotropy measurements, I have been able to observe evidence of hindered rotational motion of coumarin in monolayer films, as well as characterize the motion of coumarin within other samples.  These measurements help in describing the motion of coumarin and are important in understanding radiative and non-radiative energy processes of molecular rotors.

 

 

 

 

Student Author(s): 

Shaw, Samantha L.

Department(s):

Physics

Research Mentor(s): 

John M. Blondin/Physics

Title of Presentation:

Linear Growth of Non-Axisymmetric SASI Modes in Core Collapse Supernovae

 

 

Two-dimensional axisymmetric simulations have shown that the post-bounce accretion shock in core collapse supernovae is subject to the Spherical Accretion Shock Instability, or SASI, and that the SASI includes linearly growing axisymmetric modes.  Recent three-dimensional simulations of core-collapse supernovae have revealed the existence of non-axisymmetric modes of the SASI.  Here we investigate the growth of these modes using two-dimensional simulations of  the accretion flow in the equatorial plane of a core-collapse supernova.  By perturbing a steady-state model we are able to excite both one and two-armed spiral modes that grow exponentially with time, demonstrating that these are linearly unstable modes.  By tracking the distribution of angular momentum, we demonstrate that these modes are able to efficiently separate the angular momentum of the accretion flow (which maintains a net angular momentum of zero), leading to a gradual spin up of the underlying accreting proto-neutron star.

 

 

 

Student Author(s): 

Speller, Danielle H.

Department(s):

Physics

Research Mentor(s): 

Hans D. Hallen/Optics

Title of Presentation:

Manipulation of a Cell Nucleus with a Novel Nanoprobe Device

 

 

The ability to control the nucleus of a cell has the potential to broaden techniques in medical and scientific research, by allowing experimenters to develop new ways to explore the inner mechanisms of the basic structures of life.  New methods for cellular study enabled by a fiber optic-based nanoprobe device contain the potential for the development of new scientific and medical apparatus, in addition to an increase in knowledge of cell behavior in response to stimuli.  Single mode optical fibers sharpened via chemical etching were coated with a metal.  The metal was oxidized and a hydrophobic self-assembled monolayer (SAM) applied.  The nucleus of a stamen hair cell of Setcreasea Purpurea (Purple Heart Plant) is attracted to this hydrophobic probe and attaches itself to it.  A variable voltage applied to the metal coating of the probe can be used to disengage the nucleus from the tiphen within range of other cellular material. We were able to insert the nucleus from one cell into another.  These results suggest that the nucleus is hydrophobic.  We consider several models for the observations. 

 

 

 

Student Author(s): 

Timpy, Evan L.

Department(s):

Marine, Earth, and Atmospheric Sciences

Research Mentor(s): 

William J. Showers/Marine, Earth and Atmospheric Sciences

Title of Presentation:

Identifying Nitrate Sources in a Forested Stream Using Stable Isotope Analysis

 

 

The natural abundance of nitrogen and oxygen isotopes in nitrate where used to identify the source of nitrate to surface waters of a forested stream.  Large volumes of stream waters were obtained across a storm event, with samples taken at base, rising, peak and falling discharge.  The samples were filtered and analyzed with an ion chromatograph.  The samples were found to be low in nitrate (non-detectable to 1 uM) and qualitatively high in dissolved organic carbon (DOC).  The samples were passed through cation exchange resins to remove DOC, then anion exchange resins to absorb nitrate.   The nitrates were eluted with 3M HCl, reacted with silver oxide and freeze dried prior to analysis with a continuous flow mass spectrometer.  The isotopic results for the nitrate analyzed are expected to be within the range of atmospheric deposition and microbial nitrification found in comparable forested catchments.  Our results may predict the flux of atmospherically derived nitrogen in N-limited stream ecosystems for future studies.

 

 

 

 

Student Author(s): 

Tweedy, Eamonn

Joyner, Sarah Lynn

Vogl, Chris

Dixon, Anthony R.

Benim, Robert

Department(s):

Mathematics

Research Mentor(s): 

Mette S. Olufsen/Mathematics

Hien Tran/Mathematics

Title of Presentation:

Heart Rate Regulation During the Postural Change from Sitting to Standing

 

 

During postural change from sitting to standing, blood pools in the lower extremities of the body. This effect leads to a decrease in blood pressure in the upper body and the brain and an increase in blood pressure in the legs. In subjects who suffer from orthostatic intolerance, postural change may cause dizziness, light-headedness, or even fainting. The exact function of the cardiovascular and respiratory regulatory mechanisms is not well understood, and this work aims to develop a mathematical model that can help describe these regulatory mechanisms in more detail. As part of a larger model developed to understand these regulation mechanisms, this submodel explains heart rate changes observed during postural change from sitting to standing. In this model, blood pressure is used as an input to determine nervous system responses and corresponding chemical changes, which directly affect heart rate. Key elements of the heart rate model include a time-delay between sympathetic and parasympathetic nervous responses and an impulse function that accounts for the subject’s physical muscular preparation for standing. Model parameters were optimized to create a curve that best fit the heart rate data gathered from a young subject, and model analysis has been performed to validate this model against groups of healthy young, healthy elderly, and hypertensive elderly subjects. Parameter sensitivity analysis will allow the various components of the model to be evaluated further. Parameter analysis will help to characterize these groups of patients and will provide information that may aid in diagnosis and treatment planning. This is a key application that is particularly valuable to the medical community.

 

 

 

 

Student Author(s): 

Williard, Mary

Wessels, Laura

Department(s):

Keith Weninger/Physics

Research Mentor(s): 

M.-H. Whangbo/Chemistry

Title of Presentation:

Membrane Fusion and Sindbis Virus Infection

 

 

 

Sindbis is an enveloped virus that is a model system for mosquito-borne viruses causing human disease, including yellow fever, dengue fever, and West Nile virus.  A better understanding of Sindbis' infection mechanism may lead to improved treatment and prevention of these devastating diseases.  To replicate, all viruses must deliver their genetic material into the interior of cells in order to use a cell's machinery and energy.  When entering a cell, the genome of enveloped viruses must traverse two lipid bilayers:  the viral membrane and the targeted cell's membrane.  Membrane fusion is a fundamental biological process that many enveloped viruses use to release their genetic material into cells.  Although membrane fusion is widely believed to be essential for infection by all enveloped viruses, for most viruses, the evidence for membrane fusion during cell entry remains indirect at best.   We have labeled influenza and Sindbis viruses with fluorescent probes in order to examine the role of membrane fusion in cell entry.  We confirm that both viruses rapidly fuse to artificial protein free membranes in response to acidic conditions.  We further find that decreased pH rapidly triggers fusion of influenza to live cell membranes, whereas Sindbis shows no evidence of low-pH triggered membrane fusion with cells. 

 

 

 

 

Student Author(s): 

Wilson-Short, Gareth B.

Department(s):

Chemistry

Research Mentor(s): 

M.-H. Whangbo/Chemistry

Title of Presentation:

Spin Dimer Analysis of the Ordered Magnetic Structures of the Double Perovskites A2RMoO6 and A2RRuO6 (A = alkaline earth, R = rare earth)

 

 

The double perovskites A2RMO6 (A = alkaline earth, R = rare earth, M = Ru, Mo) consist of corner-sharing RO6 and MO6 octahedra to form the NaCl-type structure, and their charge balance is given by (A2+)2(R3+)(M5+)(O2) 6. These solid state compounds exhibit a wide range of temperatures, TN, at which their spins undergo a three-dimensional antiferromagnetic ordering. In this ordered magnetic structure, planes containing ferromagnetically ordered R3+ and M5+ ions order antiferromagnetically (i.e., the Type I antiferromagnetic structure in an FCC lattice). To help understand these observations, we estimated the relative strengths of the spin exchange interactions between the M5+ ions (M = Mo, Ru) in A2RRuO6 and A2RMoO6 by performing spin dimer analysis based on extended Hückel tight-binding electronic structure calculations. Results of our study and their implications are discussed.

 

 

 

 

  • Biological Sciences abstracts

Applied Sciences (Crop, Poultry, Animal, and Horticultural Sciences)

 

 

 

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