(last updated on May 8, 2008)
Nicholas Barbuto with prof. Kenneth Singer -Photoluminescence in Doped 1-D Photonic Crystals
Interference effects inside a photonic crystals provide mechanisms for the precise control of light both within and outside of the photonic crystal. In particular the emission direction, spectrum, intensity, and dynamics can be affected by the band structure. We will study these photoluminescence properties in one-dimensional polymeric photonic crystals containing photoluminescent organic dopants, which are fabricated either by a co-extrusion/multiplication process or by stacking of individual layers. We will also be investigating applications of such structures in surface emitting distributed feedback lasers and as color and emission control elements for efficient solid state lighting.Ryan Berkheimer with Prof. Kathleen Kash -Sonoluminescence
Sonoluminescence is the process of changing a mechanical pressure into electromagnetic radiation and heat. Applying an external harmonic oscillating sound field at a certain resonant frequency to a gas bubble in a liquid chamber will force the gas bubble to oscillate its volume, shrinking and expanding with the sound field. Upon contraction, electromagnetic radiation is produced. This phenomenon is what is known as Sonoluminescence. For an air bubble in water, the radiation has been shown to achieve optical to UV wavelengths, with gas temperatures theorized at over 1000K. This project will attempt to observe and measure Sonoluminescence using air bubbles in a water solution for a control. This will involve design of a high Q bubble chamber (minimum power dissipation to energy input). Once this control is established, the gas and solution makeup will be altered to search for limits to the intensity and energy spectrum of the emitted radiation. If time permits a theoretical and possibly experimental examination will be made of the RPI acetone-uranium experiment.
Kyle Box with Prof. Harsh Mathur Title -A Quantum Algorithm for Testing for Mersenne Primes
In this project we will be looking for a quantum algorithm to solve a specific number theory problem - testing for Mersenne primes. Prime numbers play an important role in modern life, mostly in various data encryption schemes, and Mersenne primes are particularly interesting. There is currently only one quantum algorithm known to be better than its classical counterpart for an important problem. Shor's algorithm is a quantum algorithm for factoring an integer in O((log N)^3) time, while no classical algorithms can run in time that is polynomial in log N. We will attempt to find an algorithm to test if a number is a Mersenne prime which will run faster than classical algorithms.
Yvette Cendes with Prof. Corbin Covault -Test and Feasibility of a Cherenkov Detector for the Auger North Project
Cherenkov radiation can be used to reconstruct the energy of high-energy cosmic rays entering the Earth's atmosphere. A durable, low-cost Cherenkov detector will be tested with actual cosmic ray events and compared to cosmic ray shower simulations to test Cherenkov detector effectiveness. The viability of the detector as a component of the proposed Auger North project, which would enhance the performance relative to the currently proposed florescence detectors, will also be considered.David Crowley with Prof. Jie Shan -Thin Films for THz Generation
THz generation is a well known nonlinear effect that has been used in many spectroscopic methods. Most well known is time domain spectroscopy (THz TDS) which has the additional benefit of not only providing information on the amplitude changes, but also the phase change in the THz radiation as a result of traveling through a medium. THz radiation has been generated with the use of photoconductive antennas, black body sources, and optical rectification; to name a few. Optical rectification often uses crystals such as ZnTe in accord with a pulsed femtosecond laser to create the nonlinear effects which produce THz radiation. Thin films have also shown some success in showing this effect. Polymers however do not naturally align themselves in such a way that the molecules have a high order of and need to be polled or aligned with electric fields and then held in place to show a larger effect. Films necessary for THz generation will be created and then tested alongside the ZnTe crystals in order to understand their comparative efficiency in THz generation.
Michael Davidson with Prof. Harsh Mathur - Auger Processes in Semiconductor Quantum Dots
The nanostructure of quantum dots has been researched extensively in recent years, with emphasis on applications in lasers and photovoltaic cells. The unique properties derive from the tunable bandgap of the quantum confined semiconductor and the electron-hole interactions as they differ from bulk semiconductor. The dominant mechanism by which optically excited nanoparticles are believed to lose energy are Auger processes in which electrons and holes recombine without emission of radiation. We will focus on developing a theoretical framework for understanding Auger processes in nanoparticles using second-quantized methods and a mixture of analytical and computational techniques, while attempting to make contact with experiments being performed in our department.
Alison Deitz with Profs. Lawrence Krauss & Glenn Starkman -Transmission of Scientific Concepts Through Journalistic Writing
In science, new theories and discoveries are communicated to other scientists through journals and other technical publications where the equations and experimental specifics make up the majority of the information. A layperson interested in these scientific happenings is often at a loss to determine their practical significance, which makes the sciences seem like an elite club for those who can understand the technical jargon. This project will develop a science journalist, who will write about topics related to physics and particularly the physics department at Case Western Reserve University. These pieces will hone important journalistic skills including background research into various physics (and other science) fields, translating science-speak, interviewing and reporting techniques, and writing for different audiences. Armed with these skills, the science journalist can make seemingly difficult fields like physics more accessible to the general public.
Andrew Fu with Professor David Matthiesen (Department of Materials Science and Engineering) - Offshore Wind Energy Feasibility Center
The Board of County Commissioners of Cuyahoga County in partnership with Case Western Reserve University has selected a project manager for a 1-year feasibility study to determine the practicability of constructing a research center to harness wind power. This center will be drawing information from ten monopoles set out 3 miles off the coast of Lake Erie, just offshore of downtown Cleveland by the water intake crib. It is anticipated that we will be dealing with three main revenue streams: 1) Sale of electrical energy, 2) Sale of green credits and, 3) income from product testing. In addition, costs includes: operation and maintenance, power conversion and compatibility, production, research and development, and various other expenses to be determined. Our goal is to develop a pricing model that will successfully predict those future streams of revenues and expenses for the operation of this research center. If our financial models can show positive future, this will become the first offshore freshwater wind research center ever constructed.
Jonathan Glicoes with Profs. Gavin A. Buxton & Philip L. Taylor -Polymer Solar Cells from Diblock Copolymers: A Computational Investigation of Self-assembled Architectures
Current silicon based solar cell technologies have proven to be inordinately expensive to manufacture relative to the power that they are capable of generating, however the demand for clean energy production remains high. In contrast, polymer solar cells may be produced cheaply, albeit at a significantly reduced photovoltaic efficiency. Comparatively modest gains in efficiency may push polymer solar cells into the realm of economic feasibility and potentially even supersede silicon based solutions. The aim of this research is to investigate the structure-property relations in diblock copolymer solar cells. This will be accomplished by computationally obtaining the morphology of semiconductor diblock copolymer thin films. Generated morphologies will then be utilized as input into a separate Monte Carlo model of the photovoltaic properties of the solar cell to determine the resultant photovoltaic efficiency. This research will serve as the foundation for future investigations that will seek to optimize photovoltaic generation with the terminal aim of predicting solar cell architectures which may significantly improve photovoltaic production in polymer based solar cells as a guide for future experimental inquiry.
Miriam Israelowitz with Prof. David L. Wilson (Dept. of Biomedical Engineering) -Cryo-Imaging of Stem Cells
Little is known about the pathway of genetically modified stem cells that are injected into mice for such research as cancer and gene therapy. However, tagging the cells through fluorescence labeling could allow observation of the stem cell pathways and development. The method of Cryo-Imaging was developed for the purpose of providing ultra-high resolution RGB and fluorescent imaging. Using Cryo-Imaging, the specimen chosen for examination is frozen, serially sectioned, and imaged using a mouse-sized cryomicrotome, a microscope, a low light camera, and three-axis robotic positioning system. This project would focus on construction 3-D images of fluorescent tagged cancer specimen using automation, visualization, and analysis software, and improving the fluorescence light capturing method of the camera system.
Jeremy Mock with Prof. Thomas Shutt -Removing Krypton Impurities from Xenon with Chromatographic Adsorption
The Large Underground Xenon (LUX) detector uses high-purity xenon to search for WIMP dark matter particles which are theorized to interact rarely. Thus the xenon must be free of as much background radiation as possible, and krypton is a radioactive impurity found in commercial xenon. To remove the krypton, a chromatographic adsorption method is used in which xenon contaminated with krypton is carried through a charcoal column. Because the two gases have different molecular weights, the krypton drifts through the column at a faster rate and can be removed from the xenon. The theory of chromatographic adsorption predicts that a vacuum stage technique could be used to improve the rate of separation by a factor of 10. The current system purifies xenon from krypton at a rate of about 2 kg/day, and that could be increased to 20 kg/day. I will study the response of the system as a function of pressure to achieve this desired increase so the system can be realistically used to purify xenon for the LUX experiment.
Zachary Newman with Professor Kathleen Kash -Plasma-Assisted Liquid Phase Epitaxial Growth of III-Nitrides
The wide bandgap group III-nitrides including GaN, AlN, and InN are important for visible/UV optoelectronics as well as high power devices. In this project we will attempt to grow low defect single crystal films of III-nitrides on sapphire substrates. Currently III-nitrides are grown by chemical vapor epitaxy or at high pressures. These methods make growing large, high quality crystals somewhat difficult. We will synthesize films by plasma-assisted liquid phase epitaxy (PLPE), which is a low pressure synthesis technique involving microwave activated nitrogen. Parameters such as growth temperature, plasma composition and power will be varied to investigate optimal growth conditions and processes. Crystalline quality will be characterized by scanning electron microscopy and X-ray diffraction.
Daniel Riley with Prof. John Ruhl - Construction of a Cryogenic Rotational Mechanism for the SPIDER Half Wave Plate
The purpose of the project will be to design and construct a mechanism for rotating a large sapphire half wave plate in a cryogenic environment using a stepper motor to provide discrete rotations. The intent is that the design will be implemented in the SPIDER project for surveying the CMB. The project will begin by building a model of the system for lab testing. I will have to investigate if it is capable of achieving all our design parameters in a cryogenic environment. The system will need to be able to provide enough torque to rotate the load as well as provide enough speed to rotate the half wave plate in a timely manner. I will then have to investigate properties of the mechanism such as its robustness, and heat production. Finally, depending on the progress made in the testing of the mechanism, I will be examining optical properties of the sapphire half wave plate itself using a Fourier Transform Spectrometer.John Roush with Prof. Charles Rosenblatt - Growth Rates in the Linear Domain of the Rayleigh-Taylor Instability
The Rayleigh-Taylor Instability refers to the acceleration of a dense fluid through a less-dense fluid, often by the force of gravity. In such a case, it is difficult to mechanically establish the initial density gradient without introducing any mechanical perturbations. It is possible, however, using a strongly paramagnetic dense fluid in the presence of a magnetic field gradient. It is the goal of this project to show that this method produces results in agreement with previous work and accepted theory. This will be accomplished by studying the initial behavior of the fluid interface just after the magnetic field gradient is removed, specifically the exponential growth rate of the individual perturbation modes. In the early stages of the instability these growth rates are well-modeled by linear stability theory and can be directly compared to numerical calculations.
Patrick Shively with Prof. Jie Shan -Investigation of Charge Transport in Organic Photoconductors
Understanding electronic charge transport in organic materials is of both fundamental and technological importance. Phthalocyanine (Pc) derivatives belonging to a family of discotic liquid crystals will be investigated as a model system. These disk-like molecules can self-assemble into columns to create quasi-one-dimensional channels for efficient charge transport. The columns can also be aligned using an electric field creating an anisotropy of carrier mobility in the system. Time-resolved spectroscopy will be used to examine the properties of photoexcited carriers in Pc including response to an external electric field, anisotropy, and coupling to vibrations of the molecules.
William Simmons with Prof. John Ruhl - Superconducting Magnetic Bearing
The goal of this project is to design, build and test a superconducting magnetic bearing. The design may be used in a balloon borne polarimetry experiment, where it will be used to rotate a half wave plate. A superconducting bearing is optimal for this, compared to mechanical or electromagnetic bearings; superconducting bearings have notably lower heat generation, minimal frictional losses, and superior stability.
Karen Vaughn with Prof. Mehran Mehregany (Dept. of EECS) -MEMS Resonators for High-Temperature Applications
Microelectromechanical systems (MEMS) resonators are used in a variety of devices to act as a frequency reference, and, in some applications, frequency stability is required for temperatures well above 300°C. It is hypothesized that silicon carbide (SiC) resonators would perform better under such conditions than would polysilicon resonators. To test this, a few different MEMS resonator geometries will be designed and fabricated using both polysilicon and silicon carbide. Various physical properties of these resonators will then be characterized, with emphasis on their frequency stability as a function of temperature. The polysilicon and SiC versions of each resonator geometry will then be compared to determine the possible advantages of SiC in high-temperature applications.
Erik Walker with Prof. Charles Rosenblatt -Control of an Oil Drop Formation in a Liquid Crystal Matrix
When an oil and liquid crystal mixture is cooled quickly from high temperatures, phase separation may occur. Oil droplets appear and may form a pearl-like chain along the director. I am trying to control the direction of the oil drop formation. By heating the oil and liquid crystal mixture to the isotropic phase and cooling it slowly to the nematic phase, we can observe the phase separation of the oil and subsequent chain formation.
