22,286 research outputs found

    Propellant slosh coupling with bending Interim report

    Get PDF
    Vibrational characteristics of large liquid propellant space vehicl

    A New Component in the Radio Continua of PNe

    Get PDF
    A byproduct of experiments designed to map the CMB is the recent detection of a new component of foreground galactic emission. The anomalous foreground at 10–30 GHz, unexplained by traditional emission mechanisms, correlates with 100 mum dust emission, and is thus presumably due to dust.Is the anomalous foreground ubiquitous in the Galaxy? I will present evidence obtained with the CBI and SIMBA+SEST supporting the existence of the new component in the ISM at large, and in specific objects, in the form of a 31 GHz excess over free-free emission in PNe

    The Cluster Distribution as a Test of Dark Matter Models. IV: Topology and Geometry

    Full text link
    We study the geometry and topology of the large-scale structure traced by galaxy clusters in numerical simulations of a box of side 320 h−1h^{-1} Mpc, and compare them with available data on real clusters. The simulations we use are generated by the Zel'dovich approximation, using the same methods as we have used in the first three papers in this series. We consider the following models to see if there are measurable differences in the topology and geometry of the superclustering they produce: (i) the standard CDM model (SCDM); (ii) a CDM model with Ω0=0.2\Omega_0=0.2 (OCDM); (iii) a CDM model with a `tilted' power spectrum having n=0.7n=0.7 (TCDM); (iv) a CDM model with a very low Hubble constant, h=0.3h=0.3 (LOWH); (v) a model with mixed CDM and HDM (CHDM); (vi) a flat low-density CDM model with Ω0=0.2\Omega_0=0.2 and a non-zero cosmological Λ\Lambda term (Λ\LambdaCDM). We analyse these models using a variety of statistical tests based on the analysis of: (i) the Euler-Poincar\'{e} characteristic; (ii) percolation properties; (iii) the Minimal Spanning Tree construction. Taking all these tests together we find that the best fitting model is Λ\LambdaCDM and, indeed, the others do not appear to be consistent with the data. Our results demonstrate that despite their biased and extremely sparse sampling of the cosmological density field, it is possible to use clusters to probe subtle statistical diagnostics of models which go far beyond the low-order correlation functions usually applied to study superclustering.Comment: 17 pages, 7 postscript figures, uses mn.sty, MNRAS in pres

    A multi-wavelength view of galaxy evolution with AKARI

    Full text link
    AKARI's all-sky survey resolves the far-infrared emission in many thousands of nearby galaxies, providing essential local benchmarks against which the evolution of high-redshift populations can be measured. This review presents some recent results in the resolved galaxy populations, covering some well-known nearby targets, as well as samples from major legacy surveys such as the Herschel Reference Survey and the JCMT Nearby Galaxies Survey. This review also discusses the prospects for higher redshifts surveys, including strong gravitational lens clusters and the AKARI NEP field.Comment: Accepted for Publications of the Korean Astronomical Society (September 30, 2012 issue, volume 27, No. 3), Proceedings of the Second AKARI conference, Legacy of AKARI: A Panoramic View of the Dusty Universe. 6 page

    Oblivion: Mitigating Privacy Leaks by Controlling the Discoverability of Online Information

    Get PDF
    Search engines are the prevalently used tools to collect information about individuals on the Internet. Search results typically comprise a variety of sources that contain personal information -- either intentionally released by the person herself, or unintentionally leaked or published by third parties, often with detrimental effects on the individual's privacy. To grant individuals the ability to regain control over their disseminated personal information, the European Court of Justice recently ruled that EU citizens have a right to be forgotten in the sense that indexing systems, must offer them technical means to request removal of links from search results that point to sources violating their data protection rights. As of now, these technical means consist of a web form that requires a user to manually identify all relevant links upfront and to insert them into the web form, followed by a manual evaluation by employees of the indexing system to assess if the request is eligible and lawful. We propose a universal framework Oblivion to support the automation of the right to be forgotten in a scalable, provable and privacy-preserving manner. First, Oblivion enables a user to automatically find and tag her disseminated personal information using natural language processing and image recognition techniques and file a request in a privacy-preserving manner. Second, Oblivion provides indexing systems with an automated and provable eligibility mechanism, asserting that the author of a request is indeed affected by an online resource. The automated ligibility proof ensures censorship-resistance so that only legitimately affected individuals can request the removal of corresponding links from search results. We have conducted comprehensive evaluations, showing that Oblivion is capable of handling 278 removal requests per second, and is hence suitable for large-scale deployment

    Dynamic stability of a flexible booster subjected to a gimbled, periodically-varying end thrust Technical memorandum no. 104

    Get PDF
    Dynamic structural behavior of large rocket booster synthesized by two thin-walled cylinders and subjected to periodically varying end thrus

    Photosynthesis in Aspen Bark During Winter Months

    Get PDF
    • …
    corecore