Summer 2000 Symposium Abstracts

High Redshifted Galaxies in the Hubble Deep Field
Carla L. Adams
advisor: Professor Andrew Connolly
The Hubble Deep Field (HDF) is the deepest multicolor image of an area on the sky taken to date. Because the universe is expanding, galaxies are moving away from us, and thus the light we see from them is redshifted. This redshift allows us to see the galaxies when they were very young. We can determine the redshift of the galaxies by resolving the image. One of the best methods for determining redshifts is spectroscopy. However, spectroscopy can only be successfully performed on the brightest objects. Out of the 1686 galaxies in the HDF, about 150 galaxies have a measured spectroscopic redshift. Therefore, another method must be used to determine the redshift. Our method measures the photometric redshift. We used the fluxes from each pixel to determine the redshift of each galaxy in the HDF. Photometric redshifts have been successfully determined before by other research groups, but not on a pixel-by-pixel basis. From this technique, we are able to determine a galaxy's formation as a function of redshift.

Penning Ionzation Studies
Larissa Bifano
advisor: Dr. Peter Siska
Penning Ionization is one of the possible results of a reaction involving a metastable species and another reactant. In this process, the metastable species ionizes the other reactant producing a non excited species, an ion and an electron. The reaction to be studied this summer is excited Helium and Carbon Monoxide. In order to study this system, two aspects of the reaction need to be analyzed through an angular distribution study and an energy analysis. The angular distribution study provides information on the direction of the velocity of the products. Coupling this with the energy distribution, which indicates the energy the products have at specific angles, the direction and magnitude of the velocity vectors are easily computed. Computer programs then create a contour map of the reaction from this data. This contour map provides information on the velocities of the products in the center of mass system. Modeling the reaction using quantum mechanics enables one to evaluate the experimental results and approximate the potential surface of the reaction. This surface can give insight into the bonding occurring during and after the reaction.

Appilcations of Nonlinear Optics in LASER Technology: The Optical Parametric Amplifier
Vasilica Crecea
advisor: Dr. David Snoke
The optical parametric amplifier is a component of a LASER system that can convert the wavelength of the input radiation. (The input comes from a YAG laser, regenerative amplifier, and frequency doubler, so that we get 532 nm radiation that we send into the OPA). Thus, it is possible to make a tunable LASER with a wide range of wavelengths: 400-2600 nm. The OPA is made of optical components, both linear (mirrors, lenses, prisms) and nonlinear (crystals). The most important components of the OPA are the BBO crystals. Their nonlinear properties can provide outputs of different wavelengths, depending on the angle of inclination of the incident beam. Hence we can get a wide range of output wavelengths just by rotating the crystal and controlling the angle.

Investigating the Mechanical Properties of Shape Memory Alloys and their Application to Mechanical Devices
Kaisha L. Fields
advisor: Dr. Oladipo Onipede
Shape Memory Alloys are materials that, when deformed, have the ability to return to their original shape upon heating. Because of this phenomenal ability these materials are widely used in different applications. This research project investigates the mechanical, thermal, and structural properties of such materials. The project will involve experiments and simulation. One experiment will be performed to determine the change in length that a particular type of alloy undergoes as the SMA passes from its martensite phase to its austenite phase when a constant force (weight) is placed on the material. Another experiment will involve testing the resulting forces of a restrained SMA wire after it is heated. The simulation portion of all the experiments will be carried out using ANSYS, a Finite Element Analysis computer program.

Physics Education Research: What we teach and what is learned, a mismatch?
Andrea L. Habakuk
advisor: Dr. Chandralekha Singh
The difference between a student having the ability to make decisions in problem solving in physics and not having the ability to do so is determined by how well the student understands the concepts behind the problem. This research will look at the goals of an introductory physics course. It will then discuss the theory and goals of physics education research. Finally, it will delve into magnetism education research, specifically focusing on the results of a written magnetism conceptual exam to be given to students in both a calculus- and non-calculus-based introductory physics course at the University of Pittsburgh, post instruction.

Modeling and Kinematics of the Foot for Mechanical Analysis of Ankle Replacements
Opal Harrison and Ronald Moore
advisor: Professor Mark Miller
This project focuses on mechanical operation of four major bones of the foot in relation to the ankle. These bones are the navicular, talus, calcaneus, and cuboid. Coordinate systems for these bones must be established individually with respect to the ankle joint. Identification of these systems will aid in demonstrating mechanical operation of these particular bones. The accomplishment of this task will help researchers prepare to mathematically model the situation in the software application Abaqus, in which the domain is discretized. Additionally, the research has applications to improvement of prosthetic surgery. Variations of applied loads and boundary conditions will be established to analyze stress distribution in a prosthetic ankle. In successful surgery, the tibia and fibula are fused. Variations in implant positioning and loading conditions distribution will be analyzed and compared, so that better surgical implant placement can be determined.

Two Dimensional Crystallization in a Vertical Free-Standing Film
An T. Ngo
advisor: Dr. Xiao-Lun Wu
Audio frequencies applied to a vertical free-standing film of colloidal latex particles, surfactant, and water causes migration of grain boundaries to form a large, homogeneous two-dimensional crystal. The particles self-assemble into a polycrystalline structure due to forces generated by film thinning, upon careful withdrawal of the film from a concentrated suspension. Annealing of grain boundaries occurs due to capillary waves generated by vibration of the film. We seek to compare this process with a study of the crystallization of a binary mixture of particle sizes. Favorable packing structures for various mixtures have been determined through preliminary calculations of crystal density. The goal of our experiment is to determine whether binary crystallization resembles granular flow, or if there are other forces present. In this way, we hope to gain further understanding of the kinetics of two-dimensional crystallization.

Bose-Einstein Condensation of Excitons in Copper(I) Oxide
Ernest Opare
advisor: Dr. David Snoke
This project is an attempt to create a Bose-Einstein condensate of excitons in a copper(I) oxide crystal. An integral part of the project is to build a tunable laser called an Optical Parametric Amplifier (OPA) which would be tuned to provide a suitable wavelength for the creation of excitons. The luminescence from the Cu2O would be analyzed for evidence of Bose-Einstein condensation. Creation of Bose-Einstein condensation is of wide theoretical interest as well as providing novel and interesting technical issues.

Developing a Convenient Source of Cerenkov Radiation: Using Computers to Predict Results
Sarah Panitzke
adivsor: Dr. Julia Thompson
Cerenkov radiation occurs when a particle travels faster than the local speed of light in a medium. Cerenkov detectors can be used in many high-energy physics experiments to differentiate between types of particles. To test the detectors, a source of Cerenkov radiation with precise specifications would be very advantageous. In previous summers, REU students began building such a source. Computer simulations are used to help select the most efficient component combination. A very sophisticated simulation program, GEANT (written at CERN Laboratories, Geneva, Switzerland), is being used this summer. GEANT tracks particles, simulating all physical processes that occur. This summer's project will modify an existing interface to GEANT, so that it can be used to select the components of the Cerenkov radiation source.

Investigation of Adsorption/Desorption Kinetics on Carbonaceous Surfaces using Optical Reflectivity and Temperature Programmed Desorption
Justin Russell
advisor: Dr. Eric Borguet
Understanding molecular-interface interactions is key to understanding environmental processes. Carbonaceous soot particle surfaces have been implicated in heterogeneous atmospheric pollution; yet, there is a lack of fundamental understanding of the surface physics and chemistry of carbonaceous surfaces. Our investigations focus on adsorption/desorption processes, as these are frequently the rate-limiting step. Adsorption/desorption is investigated via optical differential reflectance (ODR), which provides a sensitive, non-invasive, in situ, direct probe of surface coverage during adsorption/desorption over a wide pressure range with real time resolution. Temperature Programmed Desorption (TPD) experiments, measuring desorption energies, are used to validate the optical experiments. Adsorption/desorption experiments are performed in an Ultrahigh Vacuum Chamber (UHV). A number of model adsorbents, representative of volatile organic compounds (VOCs) and molecules known to undergo two-dimensional phase transitions, have been investigated on a model carbonaceous surface (graphite) using ODR and TPD. Our experiments reveal the kinetic parameters governing these important adsorption/desorption steps.

Cosmic rays and extended air showers
Grazia V. Schoonover
advisors: Dave Kraus and Dr. Julia Thompson
Experiments have established that cosmic rays consist for the most part of protons (ie, hydrogen nuclei) and some nuclei of all other elements, together with electrons and positrons. The energy of these particles usually ranges from ~106 eV to ~1020 eV. Cosmic rays interact with particles in the highest layers of the atmosphere creating a large number of secondary particles: nuclear fragments and many unstable elementary particles including p+ p- p0 mesons, K-mesons, and others. These are called "air showers," and for large energy particles "extensive air showers." This project involves collaboration between university researchers and high school teachers to build a very large extended air shower array at low cost using the resources already present in the community. Individual particle detectors will be placed on high school buildings and then networked together via ethernet connections; thus there are no costly facilities to build and no special wiring, since schools already have Internet links. In addition to studying cosmic rays, this offers the added benefit of improved science curriculums, with long term involvement of the high school students and teachers in the research.

Reevaluation of the magnetic field in BNL E865
Anne Smith
advisor: Dr. Julia Thompson
Experiment 865 at Brookhaven National Labs was performed from 1995 to 1999. The goal was to set an upper limit on a kaon decay forbidden by the Standard Model of particle physics. Analysis of the data involves the creation of an accurate, smoothed model of the magnetic field from measurements taken at various points in the field or from knowledge of the ferromagnetic materials involved. In this project, several possible models of the field are compared with Hall probe measurements taken in 1999. The comparisons are done on the Physics Analysis Workstation (PAW).

Utilizing Quasar Absorption Lines to Study the Evolution of Neutral Hydrogen in the Universe
Charlotte Sotomayor
adivsor: Dr. Sandhya Rao
Quasars are the most luminous and distant objects in the universe. A quasar spectrum acts as a powerful probe for intervening gaseous material. This is crucial in revealing the nature of galaxies from their formation to their current state. The "damped Lyman alpha" absorption line in quasar spectra contribute 95% of the neutral hydrogen mass observed in the high and low redshift universe. The research being conducted this summer revolves around low-redshift damped Lyman alpha systems. The objective is to find the galaxy responsible for the damped absorption line in the spectrum of quasar Q0827+243. The fifteen year old paradigm that assumed these strong absorption lines are caused by spiral galaxies is being refuted. Low redshift studies are now revealing that they are caused by a mixture of galaxy types including spiral, dwarf, and low surface brightness galaxies.

Beam monitoring in MINOS
Alexander Urban
advisors: Prof. Julia Thompson, Prof. Donna Naples, and Dave Kraus
MINOS is a particle physics project being developed at Fermilab National Labs which will investigate neutrino decay. A beam of protons will be created in the particle accelerator at Fermilab; through interaction of the beam with a nearby beryllium target, a secondary beam of pions and kaons (along with many other particles) will be produced. Near the source of these hadrons the first detector will be located. The University of Pittsburgh's research contributions to the Minos project will be focused on the monitoring and study of the secondary beam and predicting the initial neutrino spectrum. A preliminary proposal was put forth by Dave Kraus of a beam detector with minimum material and able to function in the intense high rate environment of particle decay and interactions. This detector is based on the principle of optical transition radiation. The detector will emit photons as various particles pass through, and analysis of the photon spectrum will yield information about the composition and direction of the hadron beam. My summer contribution will involve study of optical transition radiation, its application in monitoring the secondary beam in MINOS, and calculations of behavior of the radiation emitted through a solid angle.

Computer Simulation of Springback in Metals
Ryan E. West
advisor: Dr. Oladipo Onipide
Springback is the amount of elastic recovery that occurs after plastic deformation of a metal. Using a finite element analysis program, a computer model of a punch in die system is created. Applying various loads to the blank holder and punch can bend the metal blank being tested. After removing the loads from the system the amount of springback can be determined. By varying certain factors, such as the coefficient of friction of the metal, the force applied to the blank holder, and the radius of curvature of the die, one can determine the effect of these factors on the amount of springback that occurs. Computer simulation of springback in metals is an important area of study for the metal forming industry.