Bulletin of the American Physical Society
Joint Fall 2010 Meeting of the Texas Sections of the APS, AAPT, Zone 13 of SPS and the National Society of Hispanic Physicists
Volume 55, Number 11
Thursday–Saturday, October 21–23, 2010; San Antonio, Texas
Session FA2: Astrophysics, Astronomy, Space Science II |
Hide Abstracts |
Chair: Soma Mukherjee, University of Texas at Brownsville Room: University Center III Bexar Room, 1st floor |
Friday, October 22, 2010 3:00PM - 3:12PM |
FA2.00001: Laser Stabilization Techniques for Gravitational-wave Detectors Sergio Cantu, Malik Rakhmanov, Volker Quetschke The Laser Interferometer Gravitational-Wave Observatory (LIGO) consists of two 4-km detectors whose mission is to directly observe fluctuations of space-time called gravitational waves. To achieve the necessary sensitivity these detector require precise control of the displacements of many components of the interferometer, and high level of stability of the laser frequency and the purity of laser mode. We present a summary of the experiments with laser stabilization techniques utilized on the LIGO Pre-Modecleaner (PMC) cavity and the Interferometric Displacement Sensor (IDS). The PMC is a triangular ring resonator which suppresses the high order modes in the laser beam, keeping the fundamental mode unaffected, thereby improving the mode content of the laser beam. The IDS based on a simple Michelson interferometer has the sensitivity of 10 fm/rHz which greatly exceeds the sensitivity of the commercial devices (on the order of 10 pm/rHz) which are currently used by LIGO. We measured the performance of both PMC and IDS in table optical interferometer experiments. [Preview Abstract] |
Friday, October 22, 2010 3:12PM - 3:24PM |
FA2.00002: The Formation of Spaces in the Universe and Its Expansion James Wang This article considers multi-layered space. A model for longitudinal space is presented indicating the cause of interaction and relationship among the longitudinal spaces. An interpretation is presented for the real cause of the ``gravitational force'' phenomenon. The universe as stated in physics can be large or small. It is believed that the universe is made up of many multi-layered, independent but interacting spaces and times. Here, we want to emphasize that the interaction we speak of is a one-way interaction from higher spaces to lower spaces. The effect may also be restricted to a limited number of spaces. [Preview Abstract] |
Friday, October 22, 2010 3:24PM - 3:36PM |
FA2.00003: Cluster analysis of simulated gravitational wave triggers using constrained validation clustering Ting Zhang, Lappoon Tang, Soma Mukherjee The data collected in the science run of LIGO calls for a thorough analysis of the glitches seen in the gravitational wave channels, as well as in the auxiliary and environmental channels. Rapid growth in size and number of available databases requires fast and accurate data mining algorithms for timely glitch analysis. The study presents a new technique in cluster analysis that we call constrained validation clustering (CV clustering) for mining patterns in gravitational wave burst triggers. The approach avoids using Gaussianity assumptions on data distribution, and was shown to outperform a state of the art in clustering -- G-means -- when $K$, the number of clusters, is unknown (Tang et. al., 08); experimental results suggested that Guassian mixture assumption can be too strong as a machine learning bias in mining gravitational wave data, evidenced by very severe overfitting of data by G-means. Our current focus is on upgrading CV clustering to utilizing random sampling and stochastic optimization techniques. Preliminary results indicate that such an enhancement can potentially bring about a forty fold increase in computational efficiency while suffering minor degrade in model quality. A current future direction is in further improving quality of models learned by the algorithm for making it an effective approach for real LIGO data analysis. [Preview Abstract] |
Friday, October 22, 2010 3:36PM - 3:48PM |
FA2.00004: Classification of simulated LIGO glitches using Fast Time Series Evaluation Algorithm Papia Rizwan, Soma Mukherjee Longest Common Subsequence (LCSS) has applications in data mining whenever pairwise sequence matching is necessary. However, the process is slow and nonviable when a huge amount of data such as a large set of lengthy time series is involved. Data from the current generation of gravitational wave detectors such as LIGO (Laser Interferometric Gravitational Wave Observatory) contain a large number of spurious signals from instrumental and environmental sources that need to be distinguished from astrophysical gravitational wave signals. LCSS proves to be a useful tool to classify these glitch signals. The main idea of this work is to implement LCSS with Fast Time Series Evaluation (FTSE) algorithm on simulated data to test if the algorithm is more efficient and accurate compared to the general LCSS algorithm. The efficiency of LCSS with FTSE algorithm is compared to that of general LCSS in terms of time complexity. The accuracy is compared in terms of misclassification per number of time series. [Preview Abstract] |
Friday, October 22, 2010 3:48PM - 4:00PM |
FA2.00005: Ewald Sums for One Dimension Bruce Miller, Jean-Louis Rouet We derive analytic solutions for the potential and field in a one-dimensional system of masses or charges with periodic boundary conditions, in other words Ewald sums for one dimension. We also provide a set of tools for exploring the system evolution and show that it's possible to construct an efficient algorithm for carrying out simulations. In the cosmological setting, we compare two approaches for satisfying periodic boundary conditions, one overly specified and the other completely general. We demonstrate that they provide a nearly identical clustering evolution until the number of clusters becomes small, at which time the influence of any size-dependent boundary cannot be ignored. Finally we compare the results with other recent work with the hope of providing clarification over differences these issues have induced. We explain that modern formulations of physics require a well defined potential which is not available if the forces are screened directly. [Preview Abstract] |
Friday, October 22, 2010 4:00PM - 4:12PM |
FA2.00006: Classification of Glitch Waveforms in Gravitational Wave detector characterization Razib Obaid, Soma Mukherjee The Laser Interferometer Gravitational wave Observatory (LIGO) is taking data at its sixth science run (S6). As the sensitivity of the detectors increased, so did the rate of glitch production. Understanding the glitches by studying their parameters has become much more important since production of science data of the highest quality is one of the top priorities. We present here a technique of glitch studies through isolation of waveforms of the glitches and classifying them using multidimensional techniques that would enable us to understand the properties of each glitch and find their linkages with other subsystems in the detector. [Preview Abstract] |
Friday, October 22, 2010 4:12PM - 4:24PM |
FA2.00007: Cosmology in One Dimension: Fractal Geometry, Power Spectra and Correlation Bruce Miller, Jean-Louis Rouet Concentrations of matter, such as galaxies and galactic clusters, originated as very small density fluctuations in the early universe. The existence of galaxy clusters and super-clusters suggests that a natural scale for the matter distribution may not exist. A point of controversy is whether the distribution is fractal and, if so, over what range of scales. Here the development of scaling behavior and multifractal geometry is investigated for a family of one-dimensional models for three different, scale-free, initial conditions. The methodology employed includes: 1) The derivation of explicit solutions for the gravitational potential and field for a one-dimensional system with periodic boundary conditions (Ewald sums for one dimension); 2) The development of a procedure for obtaining scale-free initial conditions for the growing mode in phase space for an arbitrary power-law index; 3) The evaluation of power spectra, correlation functions, and generalized fractal dimensions at different stages of the system evolution. A possible physical mechanism for understanding the self-similar evolution is introduced. It is shown that hierarchical cluster formation depends both on the model and the initial power spectrum. Under special circumstances a simple relation between the power spectrum, correlation function, and correlation dimension in the highly nonlinear regime is confirmed. [Preview Abstract] |
Friday, October 22, 2010 4:24PM - 4:36PM |
FA2.00008: Nanostructured Oxygen Generators for Aerospace Life Supporting System Karen Martirosyan The solid fuel oxygen generators (SFOG) used as backup oxygen delivery systems for International Space Station (ISS). Well established SFOG formulations include sodium/lithium chlorite and metal micro-particles. However, common SFOG are accompanied by formation of high temperature spots, which decrease the efficiency and safety performance. In this report we present multicomponent nanostructured oxygen generators (NOGs) based on NaClO$_{3}$-Sn -Co$_{3}$O$_{4}$ system that allow reduction of the overall reaction temperature and elimination of the hot temperature fluctuations. The nano size reactant increases the surface contact area between the solid reagents and homogeneity of mixture as well as improves the uniformity of reaction thermal front. We describe here a novel one-step (metal nitrate--glycine) solution combustion synthesis of nanostructured highly crystalline cobalt oxide nanoparticles. Furthermore, we determined the influence of the nitrate/glycine ratio on the crystallinity and particle grain size of the Co$_{3}$O$_{4}$. The factors affecting to ignition and performance characteristics of SFOG have shown that many physical and chemical properties of the individual reactants, as well as preparation methods may significant affect on the overall behavior of the oxygen generation rate. The specific application of SFOG requires that the ignition and performance characteristics be tailored to have precise sensitivities and oxygen outputs. [Preview Abstract] |
Friday, October 22, 2010 4:36PM - 4:48PM |
FA2.00009: GM=tc$^3$ Cosmology and the Moon Louise Riofrio Relativity suggests an expanding cosmology of scale R = ct, where t is age of the Universe. Gravitation would then require that c be further related to t by: GM = tc$^3$. Where G and M are mass and gravitational constant, this simple expression predicts data from the microwave background, including 4.507034\% baryonic matter and a stable density $ \Omega = 1 $. The non-linear increase in Type 1a supernova redshifts may be precisely predicted without repulsive energies. (Riofrio, 2004) Prediction of a changing c may be tested with modern lanterns and the distant hilltop of the Moon. Our Lunar Laser Ranging Experiment has measured the Moon's semimajor axis increasing at 3.82 $\pm$ .07 cm/yr, anomalously high. The Mansfield sediment (Bills, Ray 2000) measures lunar recession at 2.9 $\pm$ 0.6 cm/yr. More recent work accurately measures a recession rate of 2.88 $\pm$ 0.05 cm/yr. LLRE differs from independent experiments by $10 \sigma$. If the speed of laser light were decaying, the Moon's apparent distance is predicted to increase by 0.935 cm/yr. An anomaly in the Moon's orbit is precisely accounted for. This interesting result may have importance for cosmology, shedding light on puzzles of ``dark energy.'' In Planck units, this may be summarised as: M = R = t. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2021 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
1 Research Road, Ridge, NY 11961-2701
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700