Literature Review: Biomimetic And Conventional Aircraft Wing Tips,
2017
International Islamic University - Malaysia
Literature Review: Biomimetic And Conventional Aircraft Wing Tips, Naseeb Ahmed Siddiqui, Waqar Asrar, Erwin Sulaeman
International Journal of Aviation, Aeronautics, and Aerospace
This paper is an attempt to summarize the effect of wing tip devices employed by birds, as well as aeronautical engineers in the past to improve the performance characteristics of aircraft. The focus is on reduction of the induced drag or drag due to lift also known as inviscid drag. This paper will provide an insight on both biomimetic and conventional wing tip approaches to reduce the induced drag. Prior analysis and experiments on the aerodynamics of airplane performance due to both these separate studies have been discussed. The needs of the industry and their past inventions have been described …
Fermi-Lat Daily Monitoring Observations Of The Microquasar Cygnus X-1,
2017
Georgia College and State University
Fermi-Lat Daily Monitoring Observations Of The Microquasar Cygnus X-1, Austin P. Waldron, Stephen R. Hood, Arash Bodaghee
Georgia College Student Research Events
Detection of gamma-ray emission from microquasars is important for understanding particle acceleration in the jet, and for constraining leptonic/hadronic emission models. We present a continuation of a 1-d likelihood analysis on gamma-ray observations by Fermi-LAT (0.1-10 GeV) of the accreting black hole candidate Cygnus X-1. Combining this gamma-ray data with available X-ray monitoring data from Swift and MAXI allowed us to reveal over a dozen days (in 2008-2016) during which Cyg X-1 displayed low-significance (3-4 sigma) excesses, many of which were contemporaneous with apparent transitions in the X-rays.
Lorentz-Symmetry Test At Planck-Scale Suppression With Nucleons In A Spin-Polarized 133 Cs Cold Atom Clock,
2017
PSL Research University
Lorentz-Symmetry Test At Planck-Scale Suppression With Nucleons In A Spin-Polarized 133 Cs Cold Atom Clock, H. Pihan-Le Bars, C. Guerlin, R.-D. Lasseri, J.-P. Ebran, Q. G. Bailey, S. Bize, E. Khan, P. Wolf
Publications
The authors introduce an improved model that links the frequency of the 133 Cs hyperfine Zeeman transitions.
The Ages Of The Thin Disk, Thick Disk, And The Halo From Nearby White Dwarfs,
2017
University of Oklahoma
The Ages Of The Thin Disk, Thick Disk, And The Halo From Nearby White Dwarfs, Mukremin Kilic, Ted Von Hippel, Jeffrey A. Munn, Hugh C. Harris, James W. Liebert, Et Al.
Publications
We present a detailed analysis of the white dwarf luminosity functions derived from the local 40 pc sample and the deep proper motion catalog of Munn et al. (2014, 2017). Many of the previous studies ignored the contribution of thick disk white dwarfs to the Galactic disk luminosity function, which results in an erronous age measurement. We demonstrate that the ratio of thick/thin disk white dwarfs is roughly 20% in the local sample. Simultaneously fitting for both disk components, we derive ages of 6.8-7.0 Gyr for the thin disk and 8.7 ± 0.1 Gyr for the thick disk from the …
Sensitivity To A Frequency-Dependent Circular Polarization In An Isotropic Stochastic Gravitational Wave Background,
2017
Swarthmore College
Sensitivity To A Frequency-Dependent Circular Polarization In An Isotropic Stochastic Gravitational Wave Background, Tristan L. Smith, Robert Caldwell
Dartmouth Scholarship
We calculate the sensitivity to a circular polarization of an isotropic stochastic gravitational wave background (ISGWB) as a function of frequency for ground- and space-based interferometers and observations of the cosmic microwave background. The origin of a circularly polarized ISGWB may be due to exotic primordial physics (i.e., parity violation in the early universe) and may be strongly frequency dependent. We present calculations within a coherent framework which clarifies the basic requirements for sensitivity to circular polarization, in distinction from previous work which focused on each of these techniques separately. We find that the addition of an interferometer with the …
The Extinction Properties Of And Distance To The Highly Reddened Type Ia Supernova Sn 2012cu,
2017
University of San Francisco
The Extinction Properties Of And Distance To The Highly Reddened Type Ia Supernova Sn 2012cu, Xiaosheng Huang, Z. Raha, G. Aldering, P. Antilogus, S. Bailey, C. Baltay, K. Barbary, D. Baugh, K. Boone, S. Bongard, C. Buton, J. Chen, N. Chotard, Y. Copin, P. Fagrelius, H. K. Fakhouri, U. Feindt, D. Fouchez, E. Gangler, B. Hayden, W. Hillebrandt, A. G. Kim, M. Kowalski, P. F. Leget, S. Lombardo, J. Nordin, R. Pain, E. Pecontal, R. Pereira, S. Perlmutter, D. Rabinowitz, M. Rigault, D. Rubin, K. Runge, C. Saunders, G. Smadja, C. Sofiatti, A. Stocker, N. Suzuki, S. Taubenberger, C. Tao, R. C. Thomas
Physics and Astronomy
Correcting Type Ia Supernova brightnesses for extinction by dust has proven to be a vexing problem. Here we study the dust foreground to the highly reddened SN 2012cu, which is projected onto a dust lane in the galaxy NGC 4772. The analysis is based on multi-epoch, spectrophotometric observations spanning from 3300–9200 Å, obtained by the Nearby Supernova Factory. Phase-matched comparison of the spectroscopically twinned SN 2012cu and SN 2011fe across 10 epochs results in the best-fit color excess of (, RMS) = (1.00, 0.03) and total-to-selective extinction ratio of (R V , RMS) = (2.95, 0.08) toward SN 2012cu …
Testing Atomic Collision Theory With The Two-Photon Continuum Of Astrophysical Nebulae,
2017
University of Kentucky
Testing Atomic Collision Theory With The Two-Photon Continuum Of Astrophysical Nebulae, Francisco Guzmán, N. R. Badnell, Marios Chatzikos, P. A. M. Van Hoof, R. J. R. Williams, Gary J. Ferland
Physics and Astronomy Faculty Publications
Accurate rates for energy-degenerate l-changing collisions are needed to determine cosmological abundances and recombination. There are now several competing theories for the treatment of this process, and it is not possible to test these experimentally. We show that the H i two-photon continuum produced by astrophysical nebulae is strongly affected by l-changing collisions. We perform an analysis of the different underlying atomic processes and simulate the recombination and two-photon spectrum of a nebula containing H and He. We provide an extended set of effective recombination coefficients and updated l-changing 2s − 2p transition rates using …
Edgar Allan Poe’S Cosmology And Natural Theology: A Constructive Postmodern Appreciation,
2017
Southern Methodist University
Edgar Allan Poe’S Cosmology And Natural Theology: A Constructive Postmodern Appreciation, Theodore Walker
Perkins Faculty Research and Special Events
Contrary to some literary classifications, Edgar Allan Poe’s book-length prose poem Eureka is not intended to be fiction. In Eureka Poe was seriously attempting to advance ‘truth’ about the universe. Poe was doing natural science and poetry in the tradition of Samuel Taylor Coleridge and other natural philosophers. Poe’s prose poem is natural scientific astronomy and cosmology, plus natural theology, not science fiction.
Hubble Parameter Measurement Constraints On The Redshift Of The Deceleration-Acceleration Transition, Dynamical Dark Energy, And Space Curvature,
2017
Embry-Riddle Aeronautical University
Hubble Parameter Measurement Constraints On The Redshift Of The Deceleration-Acceleration Transition, Dynamical Dark Energy, And Space Curvature, Muhammad O. Farooq, Foram R. Madiyar, Sara Crandall, Bharat Ratra
Publications
We compile an updated list of 38 measurements of the Hubble parameter H(z) between redshifts 0.07 ≤ z ≤ 2.36 and use them to place constraints on model parameters of constant and time-varying dark energy cosmological models, both spatially flat and curved. We use five models to measure the redshift of the cosmological deceleration-acceleration transition, zda, from these H(z) data. Within the error bars, the measured zda are insensitive to the model used, depending only on the value assumed for the Hubble constant H0. The weighted mean of our measurements is zda = 0.72 ± 0.05 (0.84 ± 0.03) for …
Perihelion Precession In The General Theory Of Relativity,
2017
Department of Physics, Utah State University
Perihelion Precession In The General Theory Of Relativity, Charles G. Torre
Tutorials on... in 1 hour or less
This is a relatively quick and informal sketch of a demonstration that general relativistic corrections to the bound Kepler orbits introduce a perihelion precession. Any decent textbook on the general theory of relativity will derive this result. My analysis aligns with that found in the good old text "Introduction to General Relativity", by Adler, Bazin and Schiffer.
Short-Period Mesospheric Gravity Waves And Their Sources At The South Pole,
2017
Merrimack College
Short-Period Mesospheric Gravity Waves And Their Sources At The South Pole, Dhvanit Mehta, Andrew J. Gerrard, Yusuke Ebihara, Allan T. Weatherwax, Louis J. Lanzerotti
Physics Faculty Publications
The sourcing locations and mechanisms for short-period, upward-propagating gravity waves at high polar latitudes remain largely unknown. Using all-sky imager data from the Amundsen–Scott South Pole Station, we determine the spatial and temporal characteristics of 94 observed small-scale waves in 3 austral winter months in 2003 and 2004. These data, together with background atmospheres from synoptic and/or climatological empirical models, are used to model gravity wave propagation from the polar mesosphere to each wave's source using a ray-tracing model. Our results provide a compelling case that a significant proportion of the observed waves are launched in several discrete layers in …
Conference Review ‘’The Astronomy In Skyscapes - Archaeoastronomy Beyond Alignments’’. Full Day Session At The National Astronomy Meeting, University Of Nottingham (United Kingdom), 27th June–1st July, 2016,
2017
Technological University Dublin
Conference Review ‘’The Astronomy In Skyscapes - Archaeoastronomy Beyond Alignments’’. Full Day Session At The National Astronomy Meeting, University Of Nottingham (United Kingdom), 27th June–1st July, 2016, Frank Prendergast
Articles
The National Astronomy Meeting (NAM) of the Royal Astronomical Society (RAS) was held at the University of Nottingham Jubilee Campus on 27th June–1st July, 2016. This event is the primary annual scientific conference for astronomers and space scientists drawn mainly from the UK and Ireland. It is sponsored and coordinated by RAS. NAM 2016 had eight plenary talks spanning topics from planets to cosmology. Additionally, there were 60 parallel sessions broadly split into five themes, one of which was archaeoastronomy. This was the third successive NAM conference to feature a parallel session on archaeoastronomy, and was organised and chaired by …
An Outline Of Cellular Automaton Universe Via Cosmological Kdv Equation,
2017
University of New Mexico
An Outline Of Cellular Automaton Universe Via Cosmological Kdv Equation, Florentin Smarandache, Victor Christianto, Yunita Umniyati
Branch Mathematics and Statistics Faculty and Staff Publications
It has been known for long time that the cosmic sound wave was there since the early epoch of the Universe. Signatures of its existence are abound. However, such a sound wave model of cosmology is rarely developed fully into a complete framework. This paper can be considered as our second attempt towards such a complete description of the Universe based on soliton wave solution of cosmological KdV equation. Then we advance further this KdV equation by virtue of Cellular Automaton method to solve the PDEs. We submit wholeheartedly Robert Kuruczs hypothesis that Big Bang should be replaced with a …
The Basic Physics Of The Binary Black Hole Merger Gw150914,
2017
California Institute of Technology
The Basic Physics Of The Binary Black Hole Merger Gw150914, B. P. Abbott, K. Gill, B. Hughey, J. Pratt, M. J. Szczepańczyk, M. Zanolin, Et Al.
Publications
The first direct gravitational-wave detection was made by the Advanced Laser Interferometer Gravitational Wave Observatory on September 14, 2015. The GW150914 signal was strong enough to be apparent, without using any waveform model, in the filtered detector strain data. Here, features of the signal visible in the data are analyzed using concepts from Newtonian physics and general relativity, accessible to anyone with a general physics background. The simple analysis presented here is consistent with the fully general-relativistic analyses published elsewhere, in showing that the signal was produced by the inspiral and subsequent merger of two black holes. The black holes …
Gravity Wave And Turbulence Transport In The Mesopause Region,
2017
Embry-Riddle Aeronautical University
Gravity Wave And Turbulence Transport In The Mesopause Region, Yafang Guo
Doctoral Dissertations and Master's Theses
Vertical transport due to dissipating gravity waves and turbulence in the mesopause region (85-100 km) are analyzed with observational data obtained from a narrow-band sodium wind/temperature lidar located at Andes Lidar Observatory (ALO), Cerro Pach´on (30.25 S, 70.73 W), Chile. The Na lidar at ALO has been in regular operation since 2010. The upgrade of the lidar system in May 2014 resulted in great improvements of the signal levels, which enabled data acquisition of high temporal and vertical resolutions reaching 6 s and 25 m. Traditional data processing utilizes signals at lower resolutions, typically at 60 s and 500 m, …
Series Solutions Of Polarized Gowdy Universes,
2017
Virginia Commonwealth University
Series Solutions Of Polarized Gowdy Universes, Doniray Brusaferro
Theses and Dissertations
Einstein's field equations are a system of ten partial differential equations. For a special class of spacetimes known as Gowdy spacetimes, the number of equations is reduced due to additional structure of two dimensional isometry groups with mutually orthogonal Killing vectors. In this thesis, we focus on a particular model of Gowdy spacetimes known as the polarized T3 model, and provide an explicit solution to Einstein's equations.
Using Hubble Parameter Measurements To Find Constraints On Dark Energy Based On Different Cosmological Models,
2017
Embry-Riddle Aeronautical University
Using Hubble Parameter Measurements To Find Constraints On Dark Energy Based On Different Cosmological Models, William Wilson, Muhammad O. Farooq
Student Works
In this paper, Hubble parameter versus redshift data, collected from multiple resources, is used to place constraints on the parameters of two current Cosmological dark energy models. The first dark energy model considered is the Standard Model of cosmology, also known as ΛCDM with spatial curvature, which is primarily based on Einstein’s General Theory of Relativity with a spatially homogeneous time-independent cosmological constant, Λ. The second is the XCDM model which parameterize dark energy as a fluid whose density can vary with time. The H(z) data collected through different experimental sources was used to put constraints on the parameters of …
The Rate Of Binary Black Hole Mergers Inferred From Advanced Ligo Observations Surrounding Gw150914,
2016
California Institute of Technology
The Rate Of Binary Black Hole Mergers Inferred From Advanced Ligo Observations Surrounding Gw150914, B. P. Abbott, K. Gill, B. Hughey, M. J. Szczepańczyk, M. Zanolin, Et Al.
Publications
A transient gravitational-wave signal, GW150914, was identified in the twin Advanced LIGO detectors on 2015 September 2015 at 09:50:45 UTC. To assess the implications of this discovery, the detectors remained in operation with unchanged configurations over a period of 39 days around the time of the signal. At the detection statistic threshold corresponding to that observed for GW150914, our search of the 16 days of simultaneous two-detector observational data is estimated to have a false-alarm rate (FAR) of
Elasticity Of Cylindrical Black Holes,
2016
California Polytechnic State University, San Luis Obispo
Elasticity Of Cylindrical Black Holes, Conrad Pearson
Physics
Black holes are regions of strong gravity, and are often regarded as behaving like drops of fluid. When this line of thought is applied to cylindrical black holes (black cylinders), a mapping can be made between known instabilities for black cylinders and ordinary fluid cylinders. However, this known correlation is increasingly less accurate for lower spatial dimensions, and I seek to correct this discrepancy in this thesis. By considering soft solids instead of pure fluids, elastic energy can be included, which brings us closer to a direct comparison. In improving this mapping, it becomes possible to better understand the behavior …
Supplement: The Rate Of Binary Black Hole Mergers Inferred From Advanced Ligo Observations Surrounding Gw150914,
2016
California Institute of Technology
Supplement: The Rate Of Binary Black Hole Mergers Inferred From Advanced Ligo Observations Surrounding Gw150914, B. P. Abbott, K. Gill, B. Hughey, M. J. Szczepańczyk, M. Zanolin, Et Al.
Publications
This article provides supplemental information for a Letter reporting the rate of (BBH) coalescences inferred from 16 days of coincident Advanced LIGO observations surrounding the transient (GW) signal GW150914. In that work we reported various rate estimates whose 90% confidence intervals fell in the range 2–600 Gpc−3 yr−1. Here we give details on our method and computations, including information about our search pipelines, a derivation of our likelihood function for the analysis, a description of the astrophysical search trigger distribution expected from merging BBHs, details on our computational methods, a description of the effects and our model for calibration uncertainty, …
