http://hdl.handle.net/1803/687 2013-05-26T04:32:55Z http://hdl.handle.net/1803/5204 Title: High-energy attosecond-width electron diffraction simulations Authors: Kidd, Daniel Abstract: Electron microscopy has been the recent subject of molecular imaging due to the strength of the electrons' interaction with the target molecule making for a detailed pattern at a small scale.[1] To achieve the best 4D image of the target, one needs sufficient spatial and temporal resolution, the prior being an issue of using electrons in the keV regime as to achieve an optimally small deBroglie wavelength, and the latter being improved by the temporal width of the electron wave packet itself.[2] In order to image the motion of the electronic structure of the target molecule, this width must be within the attosecond regime. In this paper, we use the computational method of time-dependent density functional theory (TDDFT) to model our targets of Beryllium and the Nitrogen molecule, N2 , and an incoming electron wave packet with an energy of 1500 eV. 2013-04-22T05:00:00Z http://hdl.handle.net/1803/2945 Title: Data Logistics and the CMS Analysis Model Authors: Managan, Julie E. Abstract: The Compact Muon Solenoid Experiment (CMS) at the Large Hadron Collider (LHC) at CERN has brilliant prospects for uncovering new information about the physical structure of our universe. Soon physicists around the world will participate together in analyzing CMS data in search of new physics phenomena and the Higgs Boson. However, they face a significant problem: with 5 Petabytes of data needing distribution each year, how will physicists get the data they need? How and where will they be able to analyze it? Computing resources and scientists are scattered around the world, while CMS data exists in localized chunks. The CMS computing model only allows analysis of locally stored data, "tethering" analysis to storage. The Vanderbilt CMS team is actively working to solve this problem with the Research and Education Data Depot Network (REDDnet), a program run by Vanderbilt's Advanced Computing Center for Research and Education (ACCRE). I participated in this effort by testing data transfers into REDDnet via the gridFTP server, a File Transfer Protocol which incorporates an LHC Computing Grid security layer. I created a test suite which helped identify and solve a large number of problems with gridFTP. Once optimized, I achieved sustained throughputs of 700-800 Megabits per second (Mbps) over a 1 Gigabit per second (Gbps) connection, with remarkably few failures. GridFTP is the gateway between REDDnet and CMS, and my tests were designed to exercise and harden this important tool. My results support other indications that the REDDnet system will be a successful solution to the limitations of data-tethering in the CMS computing model. Description: Honors in Physics 2009-04-20T05:00:00Z http://hdl.handle.net/1803/737 Title: Progress towards a quantum dot photovoltaic : nanocrystal deposition on structured titanium dioxide nanotubes Authors: Emmett, Kevin Abstract: While this project did not successfully produce a working photovoltaic device, significant progress has been made in the individual components of the system. This thesis describes two of those components: fabrication of an ordered TiO2 thin film as electron conducting layer, and deposition of nanocrystals onto the TiO2surface. The anodized titanium nanotubes are a significant improvement over the earlier template technique. Additionally, electrophoretic deposition presents a novel approach to nanocrystal deposition techniques and is a promising alternative to the current chemical linking procedure. However, significant new approaches to imaging the deposited nanocrystals must be developed to verify surface coverage by these deposition techniques, particularly due to the highly ordered structure of the TiO2 thin films. Future work will be directed at completing the solar cell device by depositing a hole conducting layer on top of the nanotube array. Nanocrystal-sensitized solar cells may soon prove to be viable alternative to silicon photovoltaics.; College of Arts & Science Description: Honors in Physics 2008-04-01T05:00:00Z