Please look over your abstract and presentation date and time. If you find any errors, or find that you cannot present at a given session, please contact Carl J. Wenning, Conference Chairman, immediately. Sorry -- All paper sessions are full. We are no longer accepting paper submissions. Please note that papers beginning with "SRS:" are particpanting in the Student Research Symposium.
SRS: A COSMOLOGICAL POLYTROPIC EQUATION OF STATE APPLIED TO THE FIRST ORDER CLASSICAL SUPERSTRING CORRECTIONS TO THE EINSTEIN FIELD EQUATIONS. Scott Ness, Kelly McGlynn, Chad Middleton, Don Pakey, James Conwell, Keith Andrew, Eastern Illinois University, Charleston, Illinois 61920. We have searched for solutions to the superstring corrected Einstein field equations when applied to the early phase of expansion of the universe in a standard Robertson-Walker cosmology extended to ten dimensions. For a polytropic equation of state we have found some solutions consistent with the current expansion rate and compactification of the other spatial dimensions. Numerically generated solutions will be displayed graphically for some special asymptotic cases.
"TAKE 5" MINI PRESENTATIONS
Neil Schmidgall, Glenbrook South High School, Glenview, IL 60025.
Gary Wolber, Rock Island High School, Rock Island, IL 61201.
Ann M. W. Brandon and Deborah L. Lojkutz, Joliet West High School, Chicago Heights, IL 60411.
RESPONSE OF A UNIFORM MASSY LINEAR SPRING. John J. Spokas, Benedictine University, Lisle, IL 60532. The compression and expansion of a linear spring with non-negligible mass in a uniform gravitational field will be examined both with and without discrete end loadings. Some interesting properties of this system will be noted.
A CRITICAL LOOK AT HUYGEN'S CONSTRUCTION. Jason K. Ellis, K. R. Roos, and J. P. Kenny, Bradley University, Peoria, IL 61625. Huygen's construction is critically examined, drawing attention to key flaws in the traditional interpretation. A new Quantum Cellular Automation (QCA) model is advanced that takes these flaws into account, yielding a new picture of Huygen's construction.
SRS: RADICAL DENSITY MEASUREMENTS IN A DIAMOND GROWTH FLAME. Mark Welter, University of Wisconsin - Whitewater, Whitewater, WI 53190. Diamond films were grown on molybdenum substrates using an oxyacetylene welder's torch. During diamond growth conditions, highly sensitive absorption spectroscopy was used to determine molecular radical densities of CH, C2, CN, and OH in the flame. Radical densities were measured in 1mm increments from the torch tip to the substrate surface, indicating where these radicals are concentrated in the flame.
THE USE OF A PROBESCOPE IN ELECTRO-OPTICS COMMUNICATION, Fred W. Zurheide, Southern Illinois University at Edwardsville, Edwardsville, IL 62026-1654. The presentation will provide information about a relatively new electrical test devise called a ProbeScope. Working alone it displays wave forms on its LCD screen or with your PC computer for an extra-large oscilloscope display. Its use with introductory electro-optics communication equipment will be shown by viewing wave forms and voltages and the storing and printing of them. DC to 5 MHz signals will be used.
SRS: POISSON'S RATIOS IN DIAMOND/ZINCBLENDE CRYSTALS. Garnet Erdakos, Illinois State University, Normal, IL 61790. Poisson's ratios of crystals with the diamond/Zincblende structure are studied using a simple model. Based on the changes in bond-length and bond-angle elastic energy of up to second neighbor atoms when subjected to a tensile stress, two Poisson's rations, and , are calculated. A relation between the two is established and the results are compared with the available experimental data with favorable agreement. This investigation of Poisson's ratios, macroscopic properties of these materials, reveals their behavior at the microscopic level.
CHAOS AND COMPLEXITY: A GENERAL EDUCATION COURSE. Hiroshi Matsuoka and Richard F. Martin, Jr. Physics Department, Illinois State University, Normal, IL 61790-4560. We are currently teaching a new general education course called "Chaos and Complexity." This course has been designed not only to introduce students with diverse background to the ideas and methods of an emerging multidisciplinary science of nonlinear systems, chaos, and complexity but also to provide a foundation for students to understand the scientific advancements of the twenty-first century in a cultural and historical context.
AUTOMATIC RECOGNITION AND CLASSIFICATION OF GALAXIES USING COMPUTER VISION TECHNIQUES, Shaukat Goderya, Bradley University, Peoria, IL 61625. The deep field images from Hubble Space Telescope released in December of 1995 has demonstrated that astronomers now have the technology to build a database of potentially 50 billion galaxies. Morphology of these galaxies would be an enormous task if it was to be done without computer resources. In this work I investigate classification of galaxies by employing computer vision techniques. The basic design philosophy adopted for the classifier is extracting geometrical shape structures like elongation, compactness, bounding rectangle to perimeter ratio and many others and build a constrained system that will contain shape features of representative galaxies. The constrained system is then applied to images containing unknown galaxies and thus obtain their classification. The scheme can be automated completely using the currently available image processing software. Initial test of the scheme are very encouraging and further refinements and modifications are understudy.
ADSORPTION STUDIES ON CATALYTICALLY PRODUCED CARBON NANOTUBES, Erica B. Mackie, K. Lafdi, and A. D. Migone, Southern Illinois University, Carbondale, IL 62901. Methane, argon, and nitrogen volumetric adsorption and desorption isotherms were measured at temperatures above and below the adsorbate triple point, on catalytically produced carbon nanotubes. The tubes were subjected to different activation treatments. The specific area of the nanotubes was determined from the BET equation. The wetting behavior, both above and below was investigated. Solid adsorbate films do not wet the nanotubes, while liquid films wet the tubes. Adsorption-desorption curves were measured, in order to determine the presence or absence of a hysteresis loop in the data, indicative of the presence of a capillary condensate in the tubes. There is no hysteresis in the data measured for non-activated tubes (hence, no capillary condensation occurs in them), while activated tubes have hysteresis loops present.
SRS: MULTILAYER ADSORPTION ISOTHERM STUDY OF CH4 ON BN, Liv M. Arnold, S. M. Desai, and A. D. Migone Southern Illinois University, Carbondale, IL 62901. Volumetric adsorption isotherms were measured at twenty-seven temperatures between 60 and 80 K for films of CH4 on BN. All of the isotherms exhibit at least four distinct steps. The purpose of this study was to investigate whether this system exhibits re-entrant layering. We found no evidence indicative of this behavior over the temperature range studied. We will present data displaying the evolution of the third and fourth steps in the isotherms as a function of temperature. Our results will be compared with the two alternative theoretical explanations which have been proposed for re-entrant layering.
BORON CARBIDE AS A SUBSTRATE FOR PHYSISORPTION, K. Tejasen, P. Shrestha, R. A. Wolfson, and A. D. Migone Southern Illinois University, Carbondale, IL 62901. The suitability of boron carbide powder as a substrate for physisorption was investigated using adsorption isotherm measurements for methane and argon at 77.3 K. The boron carbide powders were also investigated by electron microscopy. Powders from different manufacturers were used in these studies. The boron carbide samples were subjected to different heating treatments prior to the performance of the isotherms. The best results were obtained on The boron carbide heated to 1770 C in a flowing N2 atmosphere; up to six steps can be resolved in the adsorption data for methane on these substrates.
SRS: INVESTIGATION OF RAYLEIGH SCATTERING IN MILK. Craig R. Nelson. Eastern Illinois University, Charleston, Illinois 61920. Using a nitrogen pumped tunable dye laser we investigated Rayleigh scattering in dilute milk. The laser pulse was 10ns long with an energy of approximately 50mJ with a repetition rate of 20Hz. Detection has been accomplished with a fast photodiode. Wavelength has been determined by a 0.5m monochrometer to within 0.5nm. Such parameters as wavelength, angle, and concentration have been varied to determine dependencies of scattering intensity. We will present correlations between the specified parameters and the scattered intensity.
LASER PULSE PROPAGATION THROUGH VAPOR - EXPERIMENT, Tim Boostrom, Dominic Fosco, and Brian Clark, Illinois State University, Normal, IL 61790-4560. We model two laser pulses interacting with each other and molecular potassium vapor as they propagate through the vapor. In our system, a pump laser tuned to the proper wavelength excites the potassium molecules from a low molecular energy state (1) to a higher energy state (2). The significantly weaker probe laser is tuned to the transition wavelength from state (2) to state (3). The probe laser begins to interact with the K2 molecules before the pump laser. The laser pulses are approximately 3 nanoseconds in length and contain random amplitude fluctuations. The results include emissions at the probe laser wavelength that qualitatively agree with experimental data. Further, we predict significant molecular population transfer from state (1) to state (3).
COMPUTATIONAL SIMULATION OF PULSED LASER INTERACTION WITH VAPOR. Dominic Fosco, Tim Boostrom, and Brian Clark, Illinois State University, Normal, IL 61790-4560. We model two laser pulses interacting with each other and molecular potassium vapor as they propagate through the vapor. In our system, a pump laser tuned to the proper wavelength excites the potassium molecules from the lowest molecular energy state (1) to a higher energy state (2). The significantly weaker probe laser is tuned to the transition wavelength from state (2) to state (3). The probe laser begins to interact with the molecules before the pump laser. The laser pulses are approximately 3 nanoseconds in length and contains random intensity fluctuations. The results include emissions at the probe laser wavelength that qualitatively agree with experimental data (See "Pulsed Laser Interactions with Vapor" by Tim Boostrom). Further we predict significant molecular population transfer from state (1) to state (3). (See diagram above.)
SRS: MAGNETIC PHASE DIAGRAMS OF ERBIUM, B. Frazer and Naushad Ali, Southern Illinois University, Carbondale, IL 62901. We have used resistance and magnetization measurements to construct the a and b axes phase diagrams of single crystal erbium. the magnetic phase transitions are identified as slope changes in data at constant field with increasing temperature and a constant temperature with increasing field. At zero fields we observe transitions at about 19 K (Tc), 22 K, 42 K, 48 K, 53 K, and 87 K. The dependence of these transitions as a function of applied magnetic fields allowed us to construct a H-T phase diagram of single crystal erbium along a and b axes. Recently Jehan et al [1994] have constructed the a axis magnetic phase diagram of erbium using neutron diffraction studies. We have utilized their data to provide information concerning the magnetic structure in some of the regions of our phase diagrams.
Jehan, et al, Phys. Rev. B 50, 3085 (1994).
"TAKE 5" MINI PRESENTATIONS
Robert Boeke, William Raney Harper College, Palatine, IL 60067.
Others?
QUICK AND EASY MBL SOUND LABS, Gary Wolber, Rock Island High School, Rock Island IL 61201. While many teachers are familiar with the uses of the motion detector or the force probe, additional probes exist. The microphone and its associated software can provide you and your students with several labs that can be just as enlightening as computer labs in mechanics. Sources for additional labs will be provided
STUDYING THE QUANTIZATION OF LIGHT BY COUNTING PHOTONS IN A TWO SLIT DIFFRACTION PATTERN. Michael Griswold, University of Illinois--Urbana-Champaign, Urbana, Illinois 61801. Since light behaves as a wave we can predict and observe the two slit diffraction pattern, but since light also behaves as a particle we should see the same pattern if we plot the number of photons counted vs. position. To see this we have currently been updating a photon counting experiment for the light lab by improving hardware. This has consisted of updating the computer and using new software to improve data accuracy and reduce the amount of time needed to take data. The goal is to create a system which will allow the computer to collect the data based upon parameters specified by the student and then report this data in a usable form. This will allow for more data to be taken and give more time to the student to analyze the data.
THE EXPERIMENTAL DETERMINATION OF THE ACTIVATION ENERGY FOR A SYSTEM FAR FROM EQUILIBRIUM: THE BOLOUSOV-ZHABOTINSKI REACTION. David Stier, Elizabeth Prince, Keith Andrew, Williamsville High School, Williamsville, IL 62693, Loyola Academy, Libertyville, IL 60048, Eastern Illinois University, Charleston, Illinois 61920. The B-Z reaction is a special case of an autocatalytic reaction that exhibits features of a chaotic chemical system. The reaction displays strong oscillatory behavior over a well defined concentration regime resulting in a system of coupled nonlinear rate equations. The period of oscillation exhibits a sensitive dependence upon initial conditions, a hallmark of chaotic dynamics. We have measured the oscillation period as a function of temperature to determine the activation energy and isolated wave-like disturbances corresponding to reactive wave fronts, in thin 2-d preparations of the reactants.
FINALLY, AN ADVANCED PHYSICS COURSE THAT ILLUSTRATES WHAT PHYSICS IS REALLY ALL ABOUT. John R. Young, Princeton High School, Princeton, IL 61356. An advanced physics course must be one which goes beyond the norm. The learning of additional subject matter, even at a more eloquent level, is often of little significance for most serious science students. These students actually want to explore how the introductory principles, previously learned, really apply to their world. Data accumulation, data analysis, and the understanding of why the established experimental system doesn't always work the way that one has planned, are extremely important toward nourishing a young researchers ability. The actual doing of experimental physics, has become the most important goal of this educational endeavor. This particular course has been a success at accomplishing this goal since 1986.
SRS: RELATIVISTIC MOTION OF A PARTICLE IN THE GRAVITATIONAL FIELD*, Jason C. Csesznegi, Dr. Q. Su and Dr. R. Grobe, Intense Laser Physics Theory Unit, Department of Physics, Illinois State University, Normal, IL 61790-4560. We show analytically as well as numerically that when an object reaches extremely high speeds in the downward direction, the object will start to slow down in the forward direction. This suggests that the object's motion in perpendicular directions is coupled, and that the object experiences a negative acceleration with no force experienced in that direction. This is very unusual. Such a result is useful in analyzing the relativistic motion of an electron under the strong driving force of an external laser field.
* Support: ISU Honors Prog., NSF PHY-9631245, Res. Corp. CC4089 and ISU-URG.
SRS: OPTICAL PROPERTIES OF COHERENTLY EXCITED three level MEDIA*,
Jennifer R. Csesznegi, Dr. Q. Su and Dr. R. Grobe, Intense Laser Physics Theory Unit, Department of Physics, Illinois State University, Normal, IL 61790-4560. The propagation of laser pulses in optical media such as atomic or molecular vapors or optical fibers is investigated. Before any laser pulse enters this medium, the relevant states have been brought into a spatially-dependent superposition. If this medium is subjected to a single pulse the field gives up some of its energy to the medium so that a second laser pulse (called the signal field) can be created. This signal field takes the form of an inverted, mirror-image of the medium's original excitation function. I will demonstrate this effect by using computer programs written to simulate these processes.
* Support: ISU Honors Prog., NSF PHY-9631245, Res. Corp. CC4088 and ISU-URG.
SRS: ESSENTIAL STATE ANALYSIS OF STRONG FIELD PHOTODETACHMENT*,
Kress M. Shores, Dr. Q. Su and Dr. R. Grobe, Intense Laser Physics Theory Unit, Department of Physics, Illinois State University, Normal, IL 61790-4560. A recent theoretical study questioned the stabilization of negative ions in photo-detachment. Such a conclusion was controversial. We carry out the so-called close coupling study. Our aim is to find out whether there is a suppression in the photodetachment signal. We will report first results about the photodetachment, the above threshold electron kinetic energy spectrum, and the electron spatial distribution. With this approach, we investigate the manifestation of stabilization and the robustness of this effect with respect to laser parameters including the intensity, frequency, and pulse duration.
* Support: ISU Honors Prog., NSF PHY-9631245, Res. Corp. CC4089 and ISU-URG.
SRS: REVIVALS OF IONIZATION IN THE SUPER STRONG FIELD REGIME*,
Benjamin P. Irving, Dr. Q. Su and Dr. R. Grobe, Intense Laser Physics Theory Unit, Department of Physics, Illinois State University, Normal, IL 61790-4560. The atomic stabilization has been studied theoretically. We report here the stabilization for a model atom, based on numerical solutions of the time dependent Schrödinger equation in space time with the so-called split operator method. We study the soft-core potential which mimics the long-range Coulomb attraction found in an atom. In particular we focus our attention on the recently discovered periodic modulation of ionization in the stabilization regime. This phenomena has been referred to as the revivals of ionization. We offer an explanation of the ionization revivals based on quantum interference.
* Support: ISU Honors Prog., NSF PHY-9631245, Res. Corp. CC4089 and ISU-URG.
SRS: ELECTRON WAVE PACKET SPREADING IN AN INTENSE RADIATION FIELD*, Brad A. Smetanko, Dr. Q. Su and Dr. R. Grobe, Intense Laser Physics Theory Unit, Department of Physics, Illinois State University, Normal, IL 61790-4560 A full numerical solution to the time-dependent Dirac equation is used to analyze free electrons in high intensity oscillating electric fields. We show that for certain initial conditions the spreading of a free electron in a high-intensity electric field, is inhibited not only in the direction of the oscillatory motion, but also in the plane perpendicular to that motion. Our numerical results, supported by analytical estimates, deviate significantly from the predictions of the Schrödinger equation which ignores relativistic effects.
* Support: ISU Honors Prog., NSF PHY-9631245, Res. Corp. CC4089 and ISU-URG.
COMET HALE-BOPP UPDATE, David R. Renneke, Physics Department, Augustana College, Rock Island, IL 61201, dr@helios.augustana.edu. With its light curve higher than previously predicted, Comet Hale-Bopp is putting on a terrific show this spring. Items to be discussed and illustrated include the comet's size, velocity, period of rotation, period of revolution, trajectory, and several pictures. I will show several CCD images that I have taken using an SBIG ST-6 CCD camera both through a telescope and through a 28-85 mm zoom lens. The latest pictures can be seen at our astronomy Web site: "http://helios.augustana.edu/astronomy".
TRANSIENT WAVE RESPONSE WITH DOUBLE-PULSE TV HOLOGRAPHY: ZAPPING A CYMBAL WITH A LASER NEAR THE ARCTIC CIRCLE. Thomas D. Rossing, Northern Illinois University, DeKalb, IL 60115. Using an electronic system for pulsed TV holography with a double-pulsed ruby laser at the Luleå University of Technology in Sweden, transient wave propagation on cymbal during intervals from 30µs to 480µs was recorded. The first observable bending waves, having wavelengths of about 5 mm, propagate at about 1700 m/s and reach the edge of the cymbal in about 60µs. These are quickly followed by waves of longer wavelength which scatter at the outer edge of the cymbal and also at the central dome and result in standing waves. A phase unwrapping procedure is used to obtain a three-dimensional map of the wave field.
GOOD VIBES: DESIGNING, TUNING, AND PLAYING THE MARIMBA XYLOPHONE , AND VIBRAPHONE. Laura Nickerson, and Thomas D. Rossing, Northern Illinois University, DeKalb, IL 60115. Mallet percussion instruments with tuned bars and resonators, found in most band rooms, are useful in teaching physics as well as in making music. Nearly all xylophone bars are designed so that the second mode of vibration will have a frequency 3 times that of the first, leading to a musical interval of a twelfth (octave plus a fifth). In marimba and vibraphone bars, on the other hand, the second partial is 4 times that of the fundamental, an interval of 2 octaves. Some concert marimbas are designed to have the third tuned partial lying between 9.9 and 10.3 times the fundamental. We will present samples of both the music and the physics of these instruments.
SRS: HIGH SPEED STROBE PHOTOGRAPHY TECHNIQUES. Jason S. Griesbach, University of Wisconsin--Platteville, Platteville, WI 53818. I have investigated and tested triggering techniques for use in the high speed strobe photography. I also researched strobe design and will talk briefly about the design of high speed strobes. High speed events which were photographed without using a strobe will be compared to those taken with a strobe. From these it is evident that strobe photography is a far superior method of high speed photography.
EFFECT OF KINETIC INTERACTION ON SCATTERING CROSS SECTIONS FOR . Ik-Ju Kang and Renhe Yu, Southern Illinois University at Edwardsville, Edwardsville, IL 62026. The effect of kinetic interaction, ,on the proton hydrogen atom scattering for . was numerical evaluated. The ratio of kinetic interaction effect to that of Coulomb interaction is in the order of .10^-2. (Note: Equations have been deleted here that will appear in the printed copy.)
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