Summer 2003 Abstracts for Duquesne Symposium

Chemistry of Excited Neon*^*
Constance Young
advisor: Dr. Peter Siska
Excited atom chemistry is the study of atoms whose valence electron shell has been disturbed to produce an excited configuration and a more reactive atom. The ground state noble gases are not reactive with other atoms and studies of their chemistry have been limited. The noble gases are unique because their valence shells are completely filled. After exciting the noble gases, they become more reactive than any ground state atom. Injecting energy from our electron beam gun in a vacuum chamber excites the atoms. Now we are able to react them with other atoms or molecules and to find the result of their collisions by using sensitive detectors. In my experiment, I will be reacting excited neon (Ne*) with hydrogen (H₂). The reaction may look like this: Ne* + H₂ … Ne + H₂+ + e-. This reaction is called Penning Ionization. The vacuum chamber is equipped to do many things before and after collision that provides accurate data. We will use a quadrupole mass spectrometer to detect, to discuss, and to analyze the dynamics of the H₂+, NeH₂+, and NeH+ products.

A Topic in Low Energy Neutrino Scattering Paper
Nichelle Madison
advisor: Dr. Donna Naples
High energy neutrino scattering (HENS) is relatively well explored as compared to low energy neutrino scattering (LENS). A collaboration is presently proposing the Minerva Experiment to further expand experimental data in the LENS range (energy <10 GeV), via use of the MINOS neutrino beam. Amongst the multitude of topics which the Minerva collaboration presents, this particular project seeks to understand and to proffer the size and containment of a detector necessary for the LENS range. In order to accomplish this goal, it will be beneficial to model the angular distributions for final state particles (muons, pions, and kaons) in the lab frame. Thus the angular distribution of these particles shall be plotted as a function of the fraction of energy for each type of particle. This will be studied for different detector configurations. Given this information along with the theoretical calculations of the expected cross sections, it will be possible to propose a detector appropriate for the Minerva Experiment.
Another component of the research to be done is visiting the far MINOS detector at the Soudan mine in Minnesota. This experience will be beneficial because it will provide insight on the setup and use of detectors in both the MINOS and Minerva experiments. .

Study of the material properties of Ultra High Molecular Weight Polyethylene Paper
Jasper Javon Harris
advisors: Dr.Patrick Smolinski,Dr.Dipo Onipede and Roxana Cisloiu
When looking at total-joint replacement the major concern is the wear being applied. Wear is responsible for a range of negative consequences such as fracturing of the material, ultra high molecular weight polyethylene (UHMWPE), the body reacting to debris due to wear, and possibly replacement. Therefore our objective is to study the properties of ultra high molecular weight polyethylene, the material used in total-joint replacement, in order gain a better understanding of its ability to resist wear. There will be several different approaches taken in order to achieve our objective. One approach is to determine how the direction of wear being applied affects the strength of ultra high molecular weight polyethylene. Hypothetically, when wear is applied in the same direction as the molecular chains our material becomes stronger and wear is retarded. The opposite takes place in the other directions. Another approach is to find out how well does the material resist wear when it is processed through extrusion. The intent of this research is to obtain true stress-strain curves in order to verify our previous hypothesis. In addition, these stress-strain curves are valuable for design because the behavior can be used in finite element computer models to determine stress in implants.

The Large-Scale Clustering of QuasarsPaper
Nick Allen
Andrew Connolly
Quasars are the most luminous sources in the universe, can be seen to great distances, have a compact volume, and are likely powered by accretion onto supermassive black holes. In this study, quasars will be used to study the large-scale distribution of matter in the universe. The data are drawn from the Sloan Digital Sky Survey. Quasars in the survey are identified using spectra. The spectra have been automatically classified using a computer algorithm which fails approximately ten percent of the time, causing contamination in the data. I have inspected thousands of spectra in order to assign proper classification. I will use the clean sample to investigate large-scale quasar clustering. My study will help determine how clustering in general has evolved throughout the history of the universe.

Measuring Perfusion Using MRIPaper
Paula Myers
advisor: Mike Gach
Perfusion Magnetic Resonance Imaging (MRI) measures the rate at which blood is delivered to tissue. The measure of perfusion acts as an indicator of tissue health. Applications of this imaging include diagnosis of chronic disease and the study of microvascular changes associated with functional cerebral activation. An influential advantage of MRI is that it has no ionization radiation as in x-ray techniques. Further development of techniques in MRI enable us with new ways to study the brain in great detail. Arterial spin labeling (ASL) is a noninvasive perfusion MRI technique that uses radio frequency (RF) to invert the arterial spins (magnetization). A control image (spins not inverted) is also obtained. The perfusion is proportional to the difference (control -label) image. Analyzing the perfusion difference requires the evaluation of several terms each representing different factors of (ASL). The linear velocity term will be the main focus of this experimental evaluation. We will simulate blood using a water mixture that has the same properties as blood. The velocity will be analyzed by evaluating the fluid as it flows through a mechanical phantom using MRI.

Physics Simulation Software for the ATLAS DetectorPaper
Zaheer Parpia
advisor: Dr. Vladimir Savinov
The Standard Model of elementary particles attempts to define all fundamental forces and their carrier particles. However, gravitational interaction and mass are not defined in the model.
There are several experiments currently being designed to help us answer some of these questions. The main goal of the LHC ( Large Hadron Collider) is going to be discovering and studying the properties of the so called Higgs boson, an elusive elementary particle responsible for generation of masses of all elementary particles. The Standard Model requires that at least one such important particle must exist. The ATLAS detector is being designed to record data from the collision.
To be able to carry out the simulation at the University of Pittsburgh, various simulation and computational tools need to be first configured. Once ready, physics studies with ATLFAST that include studies of two photon decay of the most likely Higgs candidate or some supersymmetry (SUSY) production process can be carried out.

Controlling Molecular Self-assembly at InterfacesPaper
Jasmine Star Yuko Ma
advisor: Dr. Eric Borguet and Tao Ye
Molecules can self-assemble into sophisticated structures on a surface. Understanding and controlling these molecular arrangements is imperative in developing nanometer scale molecular sensors and computational devices. I have used Scanning Tunneling Microscopy to investigate the structures and dynamic properties of these systems in the hope of learning how to manipulate the variables, such as functional groups, electric fields, adsorbate-substrate interactions, that control the self-assembly. Even the simplest systems, e.g. HOPG (highly oriented pyrolytic graphite) are surprisingly complex. Most published STM images only resolve every second surface atom on HOPG, Our high-resolution images of HOPG show unusual three-fold symmetry and Moir‚ pattern in the arrangement of carbon atoms. These patterns reveal ALL the surface atoms and are probably caused by the electronic perturbation from the underlying graphite layer. The self-assembled structures of liquid crystal 8CB on HOPG and eicosanol on gold are imaged and corresponding molecular patterns are deduced.

Studying Quantum Dots in Lipid BilayersPaper
Sarah Rugheimer
advisor: Dr. Xiao-Lun Wu
Quantum Dots are semiconductor nanocrystals that range in size from 3-9nm. I am studying these dots in soft media such as gels and lipid bilayers. QDs have the potential inside the vesicle membrane to make a voltage sensitive probe. Through gel electrophoresis we will separate dots of different sizes. Decreased fluorescence has been a problem we hope to solve in the formation of the gel with the quantum dots.

Identification of New QSOs to Better Understand Forground Components of the Universe Paper
Lisa Kelly
adivsor: Dr. David A. Turnshek and Michelle Belfort
Quasi-stellar objects (QSOs), are thought to be supermassive black holes surrounded by luminous accretion disks. High redshift QSOs are oftentimes used in studies to determine the foreground components of the Universe. This includes gaseous clouds and other components that would affect the luminosity of something behind them. However, an insufficient number of background QSOs are known. Some of the promising candidates for new QSOs are among two categories: those behind nearby galaxies that have a very large angular size to permit the possibility of several bright background QSOs close to the galaxy's center, and QSOs that lie within an arcmin of each other. New data from Sloan Digital Sky Survey color images suggest that new searches for quasars behind galaxies will be a successful endeavor. This project consists of observing QSO candidates for seven nights using the 2.1 m telescope at the Kitt Peak National Observatory in Arizona.