(last updated on May 10, 2007)
Matthew Bird with Charles Rosenblatt - Long Term Behavior of Rayleigh-Taylor Instabilities in Immiscible Fluids with Precise Control of Initial Conditions
A magnetic field is used to pull a less dense paramagnetic fluid below a fluid of higher density. A Rayleigh-Taylor instability occurs when the magnetic field is turned off and the denser fluid falls to the bottom. The goal of this project is to study the long-term behavior of the instability in order to compare the results with theory. Since most computational work has been done with high Atwood numbers, the experiment will ideally be performed with fluids of dramatically different densities.
Tom Boatwright with Ken Singer
Linear and Nonlinear Optical Properties of Multilayer Polymer Films - Photonic Crystals in a Polymer Laser
Recent technological developments have facilitated the creation of nanometer-scale multilayered polymer films via extrusion of polymer sheets. While groups have demonstrated that multilayered films possess properties of 1-dimensional photonic crystals, little work has been done with films produced through these new methods. Linear and nonlinear optical properties of such multilayered films created with these novel procedures will be investigated. In addition, the creation of 2-dimensional photonic crystals by writing a holographic grating in photosensitive polymers will be investigated.
Frank Calma with John Ruhl (project started January 2006)
Magnetic Bearing for Cosmic Microwave Polarimetry
Balloon borne polarimetry experiments such as the BOOMERANG experiment require adjustable polarimetry apparatus with low frictional loss or heat discharge. One such design is to use a bearing containing a half wave-plate polarimeter. Unfortunately, typical mechanical and electromagnetic designs have prohibitive heat costs and characteristic oscillations that are extremely difficult to dampen or remove.
One possible solution to this issue is the use of high temperature superconductors. The use of high temperature superconductors can be self damping, and heat and frictional loss is then only a result of eddy currents.
The purpose of this project will be to design, build and test a 6” superconducting magnetic bearing. The bearing will be designed to rotate a 10 kilogram mass at a 20 Hz. operating frequency, with the intent to achieve a coefficient of friction m <10 6 , and adequate damping and stiffness to oppose vibration.
Melissa DeLucchi with Corbin Covault
Feasibility Simulations of and Improvements Upon the X-Ray Occulting Steerable Satellite
The X-rays emitted by high energy astrophysical systems can be used to create images of these sources, which help us to better understand the structure of our universe. Unfortunately, current X-Ray detection methods achieve relatively low angular resolution, as this aspect is often compromised in favor of collecting more photons. The best angular resolution is on the order of 500 milli-arcseconds, worse by a factor of 100 than the fundamental constraint from diffraction, 3 milli-arcseconds. The purpose of the X-Ray Occulting Steerable Satellite (XOSS) project is to explore a method that could greatly increase the resolution of images taken of astronomical objects, utilizing existing X-ray detection technologies. The method employed by XOSS involves passing a coded mask between the X-ray source and the detector. The mask consists of a sheet of lead with a pattern of apertures that would allow photons to only pass through certain areas of the mask during a certain time period. Using coded aperture imaging allows for a more accurate image of the sky as the mask passes the detector. From this information, we can acquire a more accurate calculation of intensity and position of such sources, to the end of improved X-ray imaging.
Kevin Engel with Peter Kernan
Wheeler/Feynman Absorber Theory and the Radiation Arrow of Time
The laws of physics are symmetric with respect to time, yet everyday life reveals striking asymmetries. A glass, once shattered will not spontaneously reform, and waves will always move outward from a source, never inward. What causes these asymmetries and others, collectively known as the arrow of time? This project will explore the various arrows of time (eg. thermodynamic, radiation, quantum) and investigate the links between them.
Andrew Fu (with?)
Jennifer Gilbert with Robert Brown
Conceptual Integration Theory
Conceptual Integration Theory, otherwise known as blending, is a relatively new theory of learning having to do with “the unification of unremarkable concepts [creating] a full and perfect meaning” (Dancygier, 1). In essence, it is a holistic approach to gaining knowledge, learning everything “in totality,” so to speak.
Referring to “The Way We Think: Conceptual Blending and the Mind's Hidden Complexities,” a book Prof. Robert Brown suggested, I will gain a more complete knowledge of the subject. I will also refer to the work of Thomas Bing, a recent graduate of Case who also did work on conceptual blending.
The ultimate goal is to find new and innovative ways to teach Introductory Physics at the collegiate level. The method of introducing these new teaching methods may be in the form of Physics text, tutorials, demonstrations, or the structure of the class.
Michael Gisondo with Corbin Covault
Cherenkov Detector - Cherenkov Detectror for High Energy Cosmic Ray Observation
Cherenkov radiation can be used to reconstruct energy and direction of high energy cosmic rays entering Earth's atmosphere. A low cost, low maintenance, durable Cherenkov detector will be designed, constructed, and tested with actual cosmic ray events for consideration by the Auger North project team as an alternative to some of the costly fluorescence detectors currently employed by the Auger South project and proposed for the Auger North project. In addition, cosmic ray shower simulations will be carried out to test the effectiveness of adding various array geometries of multiple Cherenkov detectors to the current station setup proposed by the Auger North team.
Jonathan Glicoes with John Ruhl
Halfwave Plate Rotator and Characterization
ABSTRACT?
Alexander Grutter with Kathy Kash
Growth of ZnSiN2
Zinc Silicon Nitride (ZnSiN2 ) is an extremely wide band-gap semiconductor which has never been grown before. With this senior project I will attempt to grow ZnSiN2 by first designing and building a crystal growth system, and then by finding a “recipe” for crystal growth. Since silicon has a melting point (1414 °C) far higher than that of zinc (907), the silicon will be alloyed with gold (which is inactive in this reaction) to drastically reduce its melting point from 1414 °C to 363 °C. This lower melting temperature should make it easier for zinc in the vapor phase to condense into the alloy. Introduction of ammonia (NH 3 ) will provide nitrogen to the molten silicon and zinc, completing the reaction.
Alex Harvey with Harsh Mathur
Quantum Dots in a Strong Magnetic Field - Charging Energy of a Quantum Dot in the Thomas-Fermi Approximation
Quantum dots are nanometer scale semiconductor structures. Their small
size leads to unique behavior different from that of macroscopic
semiconductors. Our objective is to generalize the Thomas-Fermi method of
atomic physics to understand the electronic structure of quantum dots in a
strong magnetic field and to analyze the quantum dynamics of electrons.
Although the method was originally devised to study the static ground
state density of atoms at zero magnetic field, it has been generalized
to study the dynamics and high magnetic field behavior of atoms. We will
make the extension to quantum dots using both analytic and numerical
methods.
Jennifer Kalb with Robert Harvey (School of Medicine, Dept. of Physiology and Biophysics)
Function of Beta_1 and Beta_2 Adrenergic Receptors in Cardiac Myocytes
The goal of this project is to determine whether beta_2 adrenergic receptor stimulation results in compartmentalized production of cAMP in intact cardiac ventricular myocytes. This goal will be accomplished by measuring the changes in cAMP activity in intact, isolated rat ventricular myocytes using PKA- and Epac-based FRET (Fluorescence Resonance Energy Transfer) biosensors. These will be introduced into the rat cardiac myocytes using adenovirus-based expression systems. FRET will be measured using images obtained from an inverted microscope (Olympus IX70) with camera (Hamamatsu Orca ER). The images will be acquired and analyzed with Simple PCI software. The drugs used will be Isoproterenol, a nonselective beta receptor activator, ICI-118,551, a selective beta_1 antagonist, and CGP 20712A, a selective beta_2 antagonist. Another component of this project is computational; after preliminary experiments have been run to obtain necessary parameters, a simulation will be run (in C++ or Java) and compared with experimental results. This project is motivated by the desire to obtain a clearer view of the selective, possibly differently compartmentalized, responses of beta_1 and beta_2 receptors, though they both utilize a common cAMP-dependent pathway, as well as the functioning of the FRET-based biosensors.
Louis Kosnosky with Jie Shan
Multilayered Polymeric Materials for Terahertz Applications
Advances in technology have spurred an increased interest in the terahertz (THz) region of the electromagnetic spectrum, with applications in wireless communication, spectroscopy, imaging, and high-speed device characterization. Manipulating THz radiation has been investigated with semiconductor or other crystalline components. A limited number of studies with polymeric materials shows their viability as an alternative to the commonly-used inorganic materials (semiconductors et cetera). Polymers offer advantages in their low cost and ease of fabrication. Their main drawback in application is their low and small range of refractive index (RI), or equivalently, dielectric permittivity. In almost all component designs, a large difference in RI between layers is required for adequate performance. Nanostructured dopants offer a potential solution to this problem. Materials with high RIs can be added to the polymers (in low volume fractions) to increase their dielectric permittivity. Multilayered polymeric optical components for the THz region such as reflectors/filters and phase retarders will be designed and characterized. Designs will incorporate films, gratings, and nanostructured additives.
Jennifer Kotzin with Gary Chottiner
Modeling Shimmy on Bicycles
In bicycling and motorcycling, there are times in which the headtube and steerer begin to oscillate, often strongly enough to throw the rider or force a crash. Those who have experienced it have nicknamed this effect the ‘Death Wobble'. This project will be done in two parts. The first is to take existing simple mathematical models of bicycle stability and expand upon them to include a more comprehensive set of factors. Possible causes of the shimmy that are currently described in the literature include total mass and total speed as well as the weight distribution. This project will initially focus on weight distribution and the structure of the bicycle frame itself. The mathematical model and simulations will be refined by testing their predictions on a bicycle, taking suitable safety precautions.
Benjamin Kreis with Dan Akerib and Richard Schnee
The Cryogenic Dark Matter Search (CDMS) experiment is designed to detect Weakly Interacting Massive Particles (WIMPs), a leading dark matter candidate. Neutrons that collide with the nuclei of the CDMS detectors can mimic WIMP signals by producing similar ionization and phonon energy, and therefore, to optimize the experiment's sensitivity, the neutron background must be minimized. This is done by placing the detectors deep underground and implementing both active and passive shielding. The number of background neutrons is estimated and then used to determine the expected number of neutron-caused WIMP-like signals present in a given data set. Currently, with five kilograms of detector mass, CDMS can achieve zero neutron background for an exposure of two years at the Soudan Underground Laboratory. As the exposure of the experiment increases, neutrons will become a significant background for the experiment, ultimately limiting CDMS's sensitivity.
At Case, we are studying a potential improvement to the CDMS shield that would have the ability to detect the presence of unwanted neutrons. With this improvement, the detectors and modified shielding would be surrounded by a photomultiplier-tube-monitored tank of gadolinium-loaded liquid scintillator that would allow CDMS to veto WIMP-like signals caused by neutrons. In this approach, the neutron background is measured, rather than estimated, thereby lowering the expected number of unvetoed WIMP-like signals and ultimately increasing the experiment's sensitivity. Such a measurement would also provide an important cross-check of the Monte Carlo background estimations used by underground experiments worldwide.
This project will consist of simulating and characterizing the performance of the proposed shield and veto system, both as a shield and as a neutron multiplicity detector, when exposed to CDMS's neutron background.
Amy Orsborn with Robert F. Kirsch (Biomedical Engineering)
Simulation of an Above Elbow Myoelectric Prosthetic Arm - Simulation of an Above-Elbow Myoelectric Prosthetic Arm for Development of an Implanted Myoelectic Control System
Current myoelectric prosthetic arms utilize surface electrodes to obtain input control signals. Surface electrodes, however, limit the available muscles, restricting the prosthetic's ability to recreate natural motion. Implantable electrodes are one proposed method of overcoming these limitations of surface electrodes. To investigate the feasibility of implanted electrodes for myoelectric arm control, simulations of both the prosthetic and residual arm are necessary. In this project, a model the mechanical properties (mass distribution, joints, and motor properties) of a commercial above-elbow myoelectric prosthetic will be developed. Simulations with this model will be used to generate myoelectrically-controlled movements of the prosthesis that will be combined (via a separate project) with measurements of the residual limb movements to generate the overall motion of the real and prosthetic arm system. This simulator can then be used to evaluate different myoelectric control schemes in human subjects (able-bodied and amputees) without implementation of a physical prosthesis. This approach could also be used as a training regimen for amputees prior to receiving their prosthesis.
Kristin Poinar with Richard Schnee
Characterizing Electron Background with the CDMS Beta Cage - A Predecessor to a Screener of Ultra-Low-Level Radiation: the Prototype Beta Cage
The beta cage is a proposed multi-wire proportional chamber that will be the most sensitive device available to screen low-energy (200 keV or less) betas emitted at very low rates (down to $10^{-5}$ counts/keV/$cm^{2}$/day). Shielding and radiopure components will allow this sensitivity to be achieved in the full-size beta cage, which will be used to assess beta-emitting impurities on the surface of detectors for use in the Cryogenic Dark Matter Search. These impurities currently limit the experiment's sensitivity to the dark matter candidate WIMPs.
The project consists of the construction and commissioning of a smaller, prototype chamber. The prototype beta cage will enclose a 40x40x20 cm drift region and two horizontal multi-wire proportional counters, all contained within a vessel of argon gas. Samples will be placed beneath the bottom grid; emitted betas will ionize the gas atoms and produce a shower of secondary electrons, which the high-voltage anode wires of each grid will multiply and collect. Their readouts will allow discrimination of events from background and determination of the energy of each beta event. The use of the prototype chamber will assess the accuracy of isotope identification by reconstructing the beta energy spectrum.
Samuel Rivier with Harsh Mathur
Cosmic Strings and Magnetic Field
Cosmic strings are linear structures that are hypothesized to have formed in the early universe and to have had considerable influence on the evolution of the universe. Cosmic strings interact with astrophysical objects via their graviational field and electromagnetic interactions. Relatively little is known about the effect of magnetic fields on cosmic strings. In this project we intend to theoretically model the magnetic properties of specific classes of cosmic strings.
Thomas Sanders with Chris Zorman (Electrical Engineering)
Design of a Novel Microfabricated Antenna for Use in Lossy Media
Microelectromechanical systems (MEMS) technology has advanced to the point where wireless systems that incorporate microfabricated, thin film antennas are beginning to emerge, especially for harsh environment applications were wired systems are not practical options. But for such systems to be deployable, the micro-antenna must be packaged in such a way as to protect the metal conductor without affecting antenna performance. This research project will explore the use of silicon carbide as a thin film packaging technology for microfabricated antennas. Silicon carbide films of varying characteristics will be deposited onto microfabricated antennas and evaluated for their durability in harsh chemical environments. The antennas will be tested using standard characterization techniques before and after coating to determine the effect of the coating on antenna performance.
Nathan Shaman with Tom Shutt (project started in summer 2006 and finishing in fall 2006 )
Building a Radon Counter to Characterize Radon in the Case XENON Detector
We attempt to design and build a radon counter to characterize 222 Rn levels in the XENON detector. For XENON to operate effectively, extremely low background radiation levels are required. When natural 238 U decays, it eventually becomes 222 Rn. It happens that 222 Rn is a very radioactive isotope. 222 Rn eventually decays to 214 Pb, which ß-decays to 214 Bi. This creates a significant detection problem as the electrons created from the ß-Decay have the potential to have energies and detection characterisitics causing them to appear much like the events related to a WIMP interaction. As such, it is necessary to measure the 222 Rn background contained within the XENON detector chamber. By bringing to vacuum the chamber of the XENON detector, and allowing 222 Rn to diffuse into the chamber over time, the 222 Rn can be extracted and the amount present can be measured using a radon counter.
The radon counter for this purpose is based on the decay chain of 222 Rn, which will lead to positive daughter ions of 218 Po in 90% of a-decays. In addition, 218 Po a-decays into a positive ion of 214 Pb. The 218 Po ions are attracted to the surface of a PIN , so when their subsequent positive a-decays occur, these particles are attracted to the PIN diode and measured using the semiconductor properties of the diode. These events are used to construct the 222 Rn decay rate in the XENON vacuum.
Benjamin Shank with Arnold Dahm
He3 Diffusion As a Probe of Delocalized Vacancies in HCP He4
Vacancies travel through He4 crystals by quantum tunneling. NMR will be used to measure the rate of vacancy assisted diffusion of isotropic He3 impurities through the HCP lattice of He4. The rate of this motion has been tested before, but experimental results vary. He3 atoms are used as probes because they are relatively light and electrically neutral; they do not create large distortions of the lattice. Diffusion is measured in the direction normal to planar magnetic field gradients induced in the sample. Measurements will be taken in three orthogonal directions to test for anisotropic diffusion. In particular, diffusion rates may differ along the c-axis and on the basal plane. After the orientation of the c-axis is determined, diffusion along the c-axis and in two orthogonal directions on the basal plane will be measured to test this hypothesis.
Audrey Todhunter with Tanmay Vachaspati
Evolution of Cosmic Islands
We study the evolution of a ball of radiation and/or dust (``island'') in a universe driven by a cosmological constant.
Matthew Whilden with David Farrell
Optimization of a High Tc Susceptometer - Imaging Using High Tc Magnetic Susceptometry
In-vivo magnetic susceptometers using liquid helium cooled low-temperature superconducting materials have been used clinically for over twenty-five years for measuring the amount of iron in the human liver. Despite their accuracy and established medical utility, their cost (>$10 6 ) has limited their adoption to just four centers worldwide. However, recent materials advances in high temperature superconductivity have led to the creation of a susceptometer for measuring liver iron that uses these materials and so requires only liquid nitrogen for its operation. Because of its much lower cost, simplicity, and increased accuracy, this advance has greatly increased the number of potential clinical applications for in-vivo susceptometry. Furthermore, modeling the response of such instrumentation using numerical techniques has recently been found to be very useful for design purposes. In this project, we will use computer simulations to optimize the performance of the next generation of superconducting susceptometers. Specifically, we will characterize the response of six different designs and choose the most promising of these. The chosen design will then be optimized so that it can be built for general clinical use by our industrial partner (Tristan Inc).
Edgar Wilson with Corbin Covault
Timing Measurement and Angular Reconstruction for the Pierre Auger Observatory /A Measurement of the Timing Offset for the Pierre Auger Observatory
One of the great current mysteries of our universe is the origin of ultra-high energy cosmic rays. One experiment that sets out to study this mystery is the Pierre Auger Observatory based in Argentina . The experiment detects cosmic showers with energies greater than 10 19 eV using a grid of 1600 water Cherenkov surface detectors spanning over 3000 square kilometers along with four atmospheric fluorescence detectors. The Auger experiment aims to track the shower backward in time through angular reconstruction in hopes of discovering an origin. Since the ultra-high energy particles of the shower travel at very nearly the speed of light, timing measurements are critical in this reconstruction and are sensitive to nanosecond offsets. This project will focus on the timing issues involved in the Auger experiment. Specifically, we will set out to accurately calibrate the timing offset between the surface detector array and each fluorescence detector. An accurate determination of the timing offset is critical for minimizing systematics in arrival direction reconstruction using events that are detected simultaneously by both surface and fluorescence detectors. To make the measurement, we will be using a pair of custom-built GPS timing instruments. The instruments will be constructed and calibrated in the lab and then will be transported to Malargue , Argentina to make measurements at the site.
Sebastian Wyman with Lawrence Krauss
Gravitational Waves From the Early Universe
The student will initially master enough of general relativity and cosmology to understand the basic features of gravitational waves in an expanding universe. Then we will examine signatures of a stochastic background of gravitational waves from a variety of possible sources. Depending upon the intricacy of the calculations, both numerical and analytical, which will be performed by the student along with a postdoc and graduate student, one of several different detection schemes will be examined, either polarization of the cosmic microwave background in response to gravitational waves from global phase transitions, or the sensitivity to a stochastic background of gravitational waves of timing measurements of white dwarf pulsations. As the former project will occupy the bulk of the work for a graduate PhD thesis, clearly the component of the project that would be worked on by the student would only be a small part of the project. The latter project should be completely doable by the student, if we deem to move in that direction.