Physics Department News
J2138+26 is a new WZ Sge-type dwarf nova, discovered by Dae-Am Yi et al. on May 7, 2010 (CBET 2273). The object is suggested to be similar to GW Lib, another WZ Sge star outbursting in 2007, in terms of a low inclination angle and apparent brightness. J2138+26 is a binary star system with a variable light output caused by precession of the accretion disk around the white dwarf in the cataclysmic variable system. J2138 enters certain periods of outburst when it is significantly brighter, and its regular light variations (from precession), called superhumps, have a changing period. Additional photometric observation of this system provides information about the changing amplitude and period of its superhumps and outbursts, which in turn helps to determine the system's history and physical activity, as well as providing insight into cataclysmic variable systems and their behavior in general. The research in July 2010, done by the named authors and using a 0.6-m telescope from the Sternberg Astronomical Institute's branch of the Crimean Observatory in Crimea, was focused on such photometric observation. Data and analysis of the superhump periods will be presented. The analysis of data taken by Dr. Voloshina and ourselves will be presented with a focus on the changing amplitude and period of J2138, and the physical significance of these results discussed.
The Small Telescope Extrasolar Transit Searches (STExTS) project is a small aperture,
wide-angle search for planetary transits and variable stars. Observations of the open
cluster Dolidze-Dzimseleshvili 9 were made with an f/2.8 152 mm astrograph for 37
nights in 2011. Lightcurves were obtained for approximately 1900 stars that were extracted
and catalogued from the images. We report on preliminary results and characteristics
of new binary stars discovered.
Presented at the Joint Spring 2012 Meeting of the Texas Sections of the APS and AAPT
and Zone 13 of the SPS
Blaise DuFrain, Richard Olenick, Arthur Sweeney, Andrew Bechter, Eric Bechter
The STExTs project searched for transit candidates in the open cluster Dolidze-Dzimselshvili 9 in Hercules for 37 nights using a f/2.8 152 mm astrograph. Approximately 11,000 images were obtained, processed, and analyzed for signatures of transits. We will present preliminary candidates and orbital periods.
Gerard Nickel
(University of Dallas)
In digital astronomical image processing, distortion limits the quality of photometric data. Often, this precludes accurate and precise analysis of stars or planetary features imaged close to one another. This is a problem in particular for period analysis of binary stars and searching for planetary transits, due to the merging of nearby stars into the area of interest. I proposed a method which utilizes a pair of filters and pixel math to increase resolution, thereby improving astronomical image features and enabling more precise analysis thereof. Comparison of processed and unprocessed data was done by comparing signal to noise ratio and brightness profiles of each. All calculations were performed and results analyzed using Astronomical Image Processing for Windows (AIP4WIN) by Richard Berry. In many cases, previously unusable star profiles were resolved sufficiently to take photometric data from them, while those with low signal to noise ratios improved by a factor of two to three. These results suggest that the proposed method could be used to enable photometric analysis of previously un-usable data.
Physics Graduates 2011
Nine physics majors graduate in 2011.
From left to right the graduates are Luke Kersting, Kyle Meziere, Anthony Sigillito,
Christen Racciato, Andrew Miller, Paul Stauduhar, Natalie Weisse, Zofia Kaminski,
and Mary Catalano. Congratulations to all!
Physics Majors in Rome Visit Castel Gandolfo
Sophomore physics major Jeff Schniederjan reports that , "We got to see one of the two telescopes on Castel Gandolfo. We also got to see the offices where anyone who works in the Vatican Observatory spends most of their time. Our tour was courtesy of Fr. Brown. Besides working in the Observatory he is also the librarian there. So he showed us some more familiar modern day textbooks and some really old ones too. The first book is Copernicus' De Revolutionibus Orbium Coelestium 2nd edition from about 1550. Then Galileo's book that got him in trouble with the church. Also equally as notable is Newtons Principia Mathematica printed in 1713. We all had a great time getting to tour the castle and visiting with Fr. Brown."
Outstanding Presentation Award
Senior physics major Anthony Sigillito was awarded the Outstanding Student Presentation Award at the Texas Section of the American Physical Society Fall-2010 meeting in San Antonio, TX. His oral presentation "The Design and Fabrication of Bismuth Hall Effect Biosensors" stood out among the 100+ presentations of students who participated in the competition. Anthony received a $200 prize for his accomplishment. (Award announced 1/3/2011.)
Meziere Family Gift to the Physics Department
Nine UD senior (100% of the senior class!) and one UD junior physics majors gave
a talk over their summer research at the Texas Section of the American Physical Society
Fall 2010 meeting at the University of Texas, San Antonio. Seven of the students,
Zofia Kaminski, Kyle Meziere, Mary Catalano, Paul Stauduhar, Natalie Weisse, Jared
Rovny and Luke Kersting are show below along with UD Peter McDonough ('09). Students
who gave talks, but are not shown are Andrew Miller, Anthony Sigillito and Christen
Racciato.
Abstracts and Talk Titles
The Design and Fabrication of Bismuth Hall Effect Biosensors
A. Sigillito*, M. Rudolph+, V. Soghomonian+, J. J. Heremans+
*Department of Physics, University of Dallas, Irving, TX 75062
+Department of Physics, Virginia Tech, Blacksburg, VA 24061
Abstract
Because of their high sensitivity, accuracy, and low cost, the use of Hall biosensors promises to be an effective diagnostic technique that may aid in the early diagnosis of diseases. In this research, Hall sensors were fabricated from thermally evaporated bismuth thin films. The bismuth films were deposited under high vacuum onto heated Si/SiO2 substrates using a two layer deposition technique. The films varied in thickness from 60 nm to 75 nm and were etched into Hall bar geometries using photolithography and wet chemical etching. Magnetoresistance and Hall measurements were taken from 4 K to 300 K. The data indicate that the sensors may be characterized by a two conduction band model with high mobility, low density holes and low mobility, high density electrons. Results deducted from these measurements regarding charge carrier mobilities and densities will be presented. Additionally, the sensors were exposed to magnetite nanoparticles and characterized using atomic force microscopy; these results will also be reported.
This research was funded by the National Science Foundation (NSF Grant DMR-0851662).
Particle Tracking of Fluorescent Microspheres
Z. Kaminski*, J. Mueller+, and S. Berk+
*Department of Physics, University of Dallas, Irving, TX 75062
+Department of Biophysics, University of Minnesota, Minneapolis, MN, 55455
Abstract
In this research, the diffusion coefficients of the fluorescent microspheres and the relation of those coefficients to particle radius were investigated. An additional focus was to see how well the measured radius of the microspheres compared to the radius as reported by the manufacturer and to measure the distribution of radii in a sample. This study further developed the critical process of ensuring particle movement within the sample volume and made preliminary sample measurements. The methods developed for tracking microspheres will later be used to determine the radii of virus like particles (VLPs), which are a non-infectious model system of the HIV virus. Results from our measurements will be reported.
This research was funded in part by the National Science Foundation through their REU program.
The Segmented Universe: Identifying Cosmic Voids with a Multi-scale Geometric Flow
Andrew Miller*, Ali Snedden+, and Lara Arielle Phillips+
*Department of Physics, University of Dallas, Irving, TX 75062
+Department of Physics, University of Notre Dame, Notre Dame, IN 46556
Abstract
The complex, filamentary nature of large-scale dark matter and density structure in the universe has been detected by redshift surveys and modeled by large N-body simulations of cosmic evolution. We present a multi-scale geometric flow algorithm as a quantitative method for the analysis of such structure. The algorithm, adapted from medical imaging identification of brain vasculature, segments a volumetric density field according measures of local structure derived from local curvature, identifying vessel-like, sheet-like, and clump-like formations. We apply this structure segmentation to a cold dark matter (CDM) density field prepared from the Virgo Consortium's 2005 Millennium Simulation (MS) output, focusing on identification of regions of cosmic void to determine the robustness of this segmentation method through a systematic comparison of its results with those of previously published void-finding algorithms. The initial results of our application of this segmentation algorithm and the data pipeline used will be presented.
IDENTIFYING INERTIAL MODES IN A HIDE-TTechnology ManagementAN FLOW
Mary T. Catalano, University of Dallas, Robert L. Blum, Daniel P. Lathrop, Don Martin, Daniel S. Zimmerman, University of Maryland
Abstract
Inertial modes are internal wave patterns present within a bounded, rotating fluid being restored by the Coriolis force. Hide and Titmam [1] found that a cylindrical container filled with homogeneous liquid and having a thin disk mounted coaxially inside of it will display non-axisymmetric fluid flow when the differential rotation between the cylinder and the disk exceeds a critical threshold. Their essential geometry and setup were replicated and the fluid flow produced was analyzed to ascertain its relationship, if any, to the inertial modes of the cylinder. Previously, the inertial modes for this geometry had been expressed in analytical form by Zhang, et al. [2] Seeking to correlate observed fluid flows with inertial modes contributes to a broader understanding of rotational fluid behavior.
[1] "Detached Shear Layers in a Rotating Fluid". Journal of Fluid Mechanics 29, pp39-60 (1967).
[2] On Inertial Waves in a Rotating Fluid Sphere. Journal of Fluid Mechanics 437, pp103-119
(2000).
Expression of Trans-Membrane Proteins in vitro Using a Cell Free System
Natalie Weisse*, Vincent Noireaux+, Jerome Chalmeau+
*Department of Physics, University of Dallas, Irving, TX 75062
+Department of Biophysics, University of Minnesota, Minneapolis, MN 55455
Abstract
Trans-membrane proteins represent a significant portion of the proteins expressed by cells. The expression of proteins in vitro, however, remains a challenge. Numerous expression approaches have been developed with cell free expression (CFE) being one of the most promising. CFE is based on a transcription-translation system that has been extracted from E. coli bacteria. Adding the desired DNA allows expression of a selected protein, and in the presence of phospholipids the expression of trans-membrane proteins becomes possible. In order to express trans-membrane proteins in a closed native environment, the cell free system (CFS) is encapsulated with a phospholipid bilayer, creating an artificial cell. To verify protein expression, AquaporinZ (AqpZ), a well-known trans-membrane protein tagged with a green fluorescent protein (eGFP), was used so the expressed proteins could be seen under a fluorescent microscope. These artificial cells will serve as an experimental platform for testing the viability of the expressed trans-membrane proteins. If the cells can be fused to the surface of the slide using the well known streptavidin-biotin bond without bursting, the environment surrounding the synthetic cells can be changed to test the endurance of the synthetic cells and the function of the AquaporinZ proteins.
(1)Department of Physics, University of Dallas, Irving TX 75019, USA
(2)Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506, USA
(3)Department of Physics, United States Naval Academy, Annapolis MD 21402, USA
Neutron elastic and inelastic scattering angular distributions from NatFe and 23Na at incident neutron energies of 3.57 and 3.81 MeV have been measured at the University of Kentucky 7 MV Van de Graaff laboratory using neutron time-of-flight techniques. The neutron beam was produced using the 3H(p,n)3He reaction. The scattered neutrons were detected at angles between 20 and 150 degrees in 10 degree intervals with a deuterated benzene detector located approximately 3 m from the scattering samples. Neutron scattering differential cross sections were deduced. These cross sections and their uncertainties are important for understanding neutron-induced reactions in fission reactors and are important for fission reactor criticality calculations.Kyle Meziere, Su Uma Type Dwarf Nova J1625
Observation and Analysis of J1625 +1203
Lyle Mezier, Richard Olenick, and Jared Rovny, University of Dallas, Irina Voloshina
and Vladimir Metlov, Sternberg Astronomical Institute
Abstract
We observed and classied the object, J1625 +1203, in July 2010, which was discovered by the Catalina Real Time Sky Survey. Observations of this cataclysmic variable star were made over a two week period using the 60 cm telescope at the Sternberg Institute Crimean Observatory in Nauchny, Ukraine. A total of eight nights of professional grade data was collected, which was then processed and analyzed. The light curves obtained are characteristic of a Su UMa type dwarf novae undergoing a super hump outbursts. The super hump and orbital periods were calculated from the data and they further support the classifcation of J1625 as an SU UMa type dwarf nova. Data and characteristics of this object will be presented.
Christen Racciato, Crystallization of Germanium for Use in Solar Cells
CHRISTEN RACCIATO2, University of Dallas, PHIL AHRENKIEL3, South Dakota School of
Mines and Technology |
Solar cells with a Germanium substrate can reach 40% eciency on earth with the aid
of solar concentrators; however, Ge is expensive, meaning that these high-eciency
cells are feasible only for extreme applications such as outer-orbit missions. The
purpose of this research is to determine if annealing Ge thin lms may be a possible,
low-cost alternative to slicing large, thick wafers of Ge for solar cells. Samples
of Ge were deposited on transmission electron microscope (TEM) grids through vacuum
evaporation, annealed at various temperatures and lengths of time in a tube furnace,
and then analyzed through the TEM to test the annealed thin films. This tests the
ease of crystallization in Ge, and if the size of the grains is reasonable. It was
found that the Ge crystallized at relatively cost-eective temperatures, specically
temperatures over 400 C with moderate grain sizes reaching 7m. Experiments to evaluate
whether grains of the size obtained can support a photovoltaic layer will be conducted
in later research. This research was funded by the National Science Foundation (Grant#:
0852057)2Department of Physics
3Department of Nanoscience and Nanoengineering
Jared Rovny, Further Measurements of the New Dwarf Nova J2138+26
Paul Stauduhar, SCALE 6.1 Validation Testing: Unit Cell Data and Material Input
Update for Summer 2010
Physics Majors Complete Research Projects During the Summer of 2010
Jared Rovny and Kyle Meziere at the Crimean Observatory
100% of our senior physics majors completed research projects during the summer of 2010. REU Students - Mary Catalano (Sen) is at the University of Maryland; Zophia Kaminski (Sen) and Natalie Weisse (Sen) are at the University of Minnesota; Andrew Miller (Sen) is at Notre Dame; Laura Downes (Sop) is at Boston college; Anthony Sigillito (Sen) is at Virginia Tech; and Christen Racciato (Sen) is at the South Dakota School of Mines; Paul Stauduhar (Sen) is a DOE summer student at Oak Ridge National Lab; Kyle Meziere (Sen) and Jared Rovny (Jun) are working with Dr. Olenick in the Crimea completing astronomical observations(shown above) funded by the Cown Physics Endowment; and Luke Kersting (Sen) and Collin Lueck ('10) completed neutron scattering research at the University of Kentucky with Dr. Hicks funded by DOE and the Cowan Physics Endowment.
Update for Spring 2010:
The primary goal of the ATRAP project at CERN is the formation of antihydrogen atoms; as part of this process, positrons are cooled, controlled and focused by passage through a series of electromagnets, and introduced into a nested Penning-Ioffe trap, where some of them combine with antiprotons to form atoms of antihydrogen. Positron cooling is controlled by LabVIEW, a graphical programming application that allows interface with multiple sensors and power supplies that control and monitor the electromagnets. A major project undertaken at ATRAP this summer was the transfer of voltage control for ten of the electromagnets to individual biasDACs (digital-to-analog boards), ensuring that the accumulation process continues independently of LabVIEW and its possible timing delays. An overview of the LabVIEW-based communication protocol for biasDACs and the process of biasDAC programming, which is expected to increase positron-antiproton interactions at ATRAP, will be presented. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.TSS.J4.10.
The Design and Fabrication of Bismuth Hall Effect Biosensors Capable of Detecting Superparamagnetic Nanoparticles, Anthony Sigillito (University of Dallas), Martin Rudolph, J. J. Heremans, Vicki Soghomonian, and Ray Khallaher (Virginia Tech University). Because of their high sensitivity, accuracy, and low cost, the use of Hall biosensors promises to be an effective diagnostic technique that may aid in the early diagnosis of disease. Hall biosensors put out a voltage proportional to the strength of the magnetic field created by a magnetically labeled biomolecule attached to the surface of the sensor. These sensors were fabricated using bismuth thin films because bismuth has a low toxicity, low cost, and large Hall coefficient, making it an ideal material for medical applications. Hall bars were characterized by taking magnetoresistance measurements and were found to have good qualities for detecting the superparamagnetic nanoparticles that can be attached to biomolecules. One sensor was exposed to nanoparticles as a test of its efficacy with positive results. This research suggests that bismuth Hall biosensors are a promising alternative to traditional diagnostic techniques. To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.TSS.F2.3.
Update for Summer 2009:
Physics Majors Complete REU Programs During the Summer of 2009
Several physics majors and concentrators are completing research projects in REU programs around the world during the summer of 2009. Monica Lacy is at CERN as a participant in the University of Michigan's REU program; Collin Lueck is at the University of Oklahoma; Sarah Brungardt is at Penn State; and Peter McDonough is completing industrial research in San Antonio. We look forward to the return of these students to campus in August!
Texas Regional Collaborative Workshop Held on the UD Campus
More than 30 high school science teachers and science coordinators met on the University of Dallas campus July 6-10 to complete a workshop on electricity, magnetism and modern physics. Dr. Karen Jo Matsler led the week long workshop.
In May 2009 a group of 12 UD students will travel to Gunnison Colorado to use the 30-in telescope at the Gunnison Valley Observatory along with a dual channel photometer constructed at UD to search for extrasolar planets using the transit methods. This research project is supported by the Sigma Pi Sigma Research Award of the American Institute of Physics, donors, and the University of Dallas.
Two 2008 UD Graduates Receive Prestigious Fellowships
In May 2008, members of UD's Society of Physics Students (SPS) visited the cyclotron at Texas A&M University. This was an accelerated tour that SPS President Will Spearman organized!
Member of UD's Society of Physics Students chapter took a field trip to NASA in Houston in November 2006. Spearheaded by chapter President Danny Malutich, the group met with astronaut Sunyi Williams who took the group to various facilities.
As it begins a new fiscal year, the University of Dallas is pleased to announce organizational changes designed to strengthen relationships with the broad range of university stakeholders, and the addition of a new leadership position for the 52-year-old Rome Program.
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