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Sample records for astronomical beam combiner

  1. UV Written Integrated Optical Beam Combiner for Near Infrared Astronomical Interferometry

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Olivero, Massimo; Jocou, Laurent;

    2006-01-01

    A near infrared integrated optical beam combiner for astronomical interferometry is demonstrated for the first time by direct UV writing. High fringe contrast >95%, low total loss (0.7 dB), low crosstalk and broadband performance is demonstrated.......A near infrared integrated optical beam combiner for astronomical interferometry is demonstrated for the first time by direct UV writing. High fringe contrast >95%, low total loss (0.7 dB), low crosstalk and broadband performance is demonstrated....

  2. Combined ultraviolet studies of astronomical source

    Science.gov (United States)

    Dupress, A. K.; Baliunas, S. L.; Blair, W. P.; Hartmann, L. W.; Huchra, J. P.; Raymond, J. C.; Smith, G. H.; Soderblom, D. R.

    1985-01-01

    As part of its Ultraviolet Studies of Astronomical Sources the Smithsonian Astrophysical Observatory for the period 1 Feb. 1985 to 31 July 1985 observed the following: the Cygnus Loop; oxygen-rich supernova remnants in 1E0102-72; the Large Magellanic Cloud supernova remnants; P Cygni profiles in dwarf novae; soft X-ray photoionization of interstellar gas; spectral variations in AM Her stars; the mass of Feige 24; atmospheric inhomogeneities in Lambda Andromedae and FF Aquarii; photometric and spectroscopic observation of Capella; Alpha Orionis; metal deficient giant stars; M 67 giants; high-velocity winds from giant stars; accretion disk parameters in cataclysmic variables; chromospheric emission of late-type dwarfs in visual binaries; chromospheres and transient regions of stars in the Ursa Major group; and low-metallicity blue galaxies.

  3. Coherent laser beam combining

    CERN Document Server

    Brignon, Arnaud

    2013-01-01

    Recently, the improvement of diode pumping in solid state lasers and the development of double clad fiber lasers have allowed to maintain excellent laser beam quality with single mode fibers. However, the fiber output power if often limited below a power damage threshold. Coherent laser beam combining (CLBC) brings a solution to these limitations by identifying the most efficient architectures and allowing for excellent spectral and spatial quality. This knowledge will become critical for the design of the next generation high-power lasers and is of major interest to many industrial, environme

  4. Nonlinear combining of laser beams.

    Science.gov (United States)

    Lushnikov, Pavel M; Vladimirova, Natalia

    2014-06-15

    We propose to combine multiple laser beams into a single diffraction-limited beam by beam self-focusing (collapse) in a Kerr medium. Beams with total power above critical are first combined in the near field and then propagated in the optical fiber/waveguide with Kerr nonlinearity. Random fluctuations during propagation eventually trigger a strong self-focusing event and produce a diffraction-limited beam carrying the critical power. PMID:24978503

  5. Nonlinear combining of laser beams

    OpenAIRE

    Lushnikov, Pavel M.; Vladimirova, Natalia

    2014-01-01

    We propose to combine multiple laser beams into a single diffraction-limited beam by the beam self-focusing (collapse) in the Kerr medium. The beams with the total power above critical are first combined in the near field and then propagated in the optical fiber/waveguide with the Kerr nonlinearity. Random fluctuations during propagation eventually trigger strong self-focusing event and produce diffraction-limited beam carrying the critical power.

  6. Superluminal Spot Pair Events in Astronomical Settings: Sweeping Beams

    CERN Document Server

    Nemiroff, Robert J

    2014-01-01

    Sweeping beams of light can cast spots moving with superluminal speeds across scattering surfaces. Such faster-than-light speeds are well-known phenomena that do not violate special relativity. It is shown here that under certain circumstances, superluminal spot pair creation and annihilation events can occur that provide unique information to observers. These spot pair events are {\\it not} particle pair events -- they are the sudden creation or annihilation of a pair of relatively illuminated spots on a scattering surface. Real spot pair illumination events occur unambiguously on the scattering surface when spot speeds diverge, while virtual spot pair events are observer dependent and perceived only when real spot radial speeds cross the speed of light. Specifically, a virtual spot pair creation event will be observed when a real spot's speed toward the observer drops below $c$, while a virtual spot pair annihilation event will be observed when a real spot's radial speed away from the observer rises above $c...

  7. Laser driver beam combination for fast ignition

    International Nuclear Information System (INIS)

    Based on the estimated parameters of fast ignition,the requirements for laser-beam power intensity and energy are used to analyze the possibility of realizing fast ignition by coherent combination and non-coherent combination. The practical distorted wavefront is considered to analyze the far-field focal spot. Non-coherent combination needs more beams for energy requirement and to limit angle drifting in ±2 μrad through improving laser driver's stability. Coherent combination is beneficial for achieving smaller focal spot and higher power intensity, simultaneously reducing the requirement of energy, but single beam wavefront correction can not improve the power intensity in this method, which leads to combined wavefront correction of the total clear aperture with complex monitoring and control methods. Based on the requirement of parameters and wavefront correction capability, non-coherent beam combination is easier to achieve for fast ignition, however, coherent beam combination has the potential for extensive application. (authors)

  8. Integrated optic beam combiners in lithium niobate for stellar interferometer

    Science.gov (United States)

    Li, Guangyu; Eckhause, Tobias; Winick, Kim A.; Monnier, John D.; Berger, Jean-Philippe

    2006-06-01

    Integrated optics can provide compact and robust solutions for ground and space-based interferometry by integrating optical devices with different functionalities, such as spatial filters, combiners/nullers, and phase modulators, on a single chip. Lithium niobate (LiNbO 3) has two distinct advantages over silica-based technologies, including good transparency further into the near-infrared (covering J, H, K, and L bands) and the ability to support electrically-controlled phase modulation through the linear electro-optic (EO) effect. The design, fabrication and preliminary tests of integrated optic components on LiNbO 3 substrates for astronomical beam combiners operating in the H and L bands is reported. The components include single-mode waveguides of sufficient length for spatial filtering, symmetric junctions for wavelength insensitive power splitters/combiners, and electro-optic waveguide modulators for path-length control.

  9. Beam Combination for Sparse Aperture Telescopes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for funding to continue development of an alternative beam combiner for Stellar Imager (SI), a 30-aperture, interferometric telescope chosen as one...

  10. Results from ATLAS Calorimeter Combined Test Beam

    CERN Document Server

    Tarrade, F

    2007-01-01

    Beam tests of combinations of ATLAS calorimeters have been performed both for the barrel and end cap parts. During a combined test beam in summer 2004 a slice of the ATLAS barrel detector - including all detector sub systems from the inner tracker, the calorimetry to the muon system - was exposed to particle beams (electrons, pions, photons, muons) with different energies (1GeV to 350GeV). The aim was to study the combined performance of the different detector sub systems in ATLAS-like conditions. We will present the electronics calibration scheme of the electromagnetic calorimeter and its implementation. The following studies on the combined testbeam data have been performed and will be presented: performance of the electromagnetic calorimetry down to very low energies (> GeV), photon reconstruction including converted photons and position measurements using the very precise ATLAS tracker and the electromagnetic calorimeter. These measurements have been compared to Monte Carlo simulations showing the good de...

  11. Beam combination schemes and technologies for the Planet Formation Imager (PFI)

    CERN Document Server

    Minardi, Stefano; Berger, Jean-Philippe; Labadie, Lucas; Thomson, Robert R; Haniff, Chris; Ireland, Michael

    2016-01-01

    The Planet Formation Imager (PFI) initiative aims at developing the next generation large scale facility for imaging astronomical optical interferometry operating in the mid-infrared. Here we report on the progress of the Planet Formation Imager Technical Working Group on the beam-combination instruments. We will discuss various available options for the science and fringe-tracker beam combination instruments, ranging from direct imaging, to non-redundant fiber arrays, to integrated optics solutions. Besides considering basic characteristics of the schemes, we will investigate the maturity of the available technological platforms at near- and mid-infrared wavelengths.

  12. Coherent beam combining of high powerfiber lasers: Progress and prospect

    Institute of Scientific and Technical Information of China (English)

    LIU; ZeJin; ZHOU; Pu; XU; XiaoJun; WANG; XiaoLin; MA; YanXing

    2013-01-01

    The recent research progress of coherent beam combining of high power fiber lasers is reviewed. Key technologies like coherently combinable fiber laser, phase control of multiple beams and beam tilling are specially analyzed. Prospects for single coherently combinable high power fiber amplifier, beam tilling and target-in-the-loop control for propagation in real atmosphere are presented.

  13. Asymmetric Beam Combination for Optical Interferometry

    CERN Document Server

    Monnier, J D

    2001-01-01

    Optical interferometers increasingly use single-mode fibers as spatial filters to convert varying wavefront distortion into intensity fluctuations which can be monitored for accurate calibration of fringe amplitudes. Here I propose using an asymmetric coupler to allow the photometric intensities of each telescope beam to be measured at the same time as the fringe visibility, but without the need for dedicated photometric outputs, which reduce the light throughput in the interferometric channels. In the read-noise limited case often encountered in the infrared, I show that a 53% improvement in signal-to-noise ratio for the visibility amplitude measurement is achievable, when compared to a balanced coupler setup with 50% photometric taps (e.g., the FLUOR experiment). In the Poisson-noise limit appropriate for visible light, the improvement is reduced to only ~8%. This scheme also reduces the cost and complexity of the beam combination since fewer components and detectors are required, and can be extended to mor...

  14. Cascaded injection resonator for coherent beam combining of laser arrays

    Science.gov (United States)

    Kireev, Vassili [Sunnyvale, CA; Liu, Yun; Protopopescu, Vladimir [Knoxville, TN; Braiman, Yehuda [Oak Ridge, TN

    2008-10-21

    The invention provides a cascaded injection resonator for coherent beam combining of laser arrays. The resonator comprises a plurality of laser emitters arranged along at least one plane and a beam sampler for reflecting at least a portion of each laser beam that impinges on the beam sampler, the portion of each laser beam from one of the laser emitters being reflected back to another one of the laser emitters to cause a beam to be generated from the other one of the laser emitters to the beam reflector. The beam sampler also transmits a portion of each laser beam to produce a laser output beam such that a plurality of laser output beams of the same frequency are produced. An injection laser beam is directed to a first laser emitter to begin a process of generating and reflecting a laser beam from one laser emitter to another laser emitter in the plurality. A method of practicing the invention is also disclosed.

  15. The 2004 ATLAS Combined Test Beam

    CERN Multimedia

    The ATLAS CTB Team, .

    2004-01-01

    In the year 2004, ATLAS has been involved in a huge combined test beam (CTB) effort in H8. A complete slice of the barrel detector and of the Muon End-cap has been tested, with the following clear goals: pre-commission the final elements and study the detector performance in a realistic combined data taking. Thanks to this experience, a lot of expertise in the operations has been acquired and much data (~ 4.6 TB of data, ~ 90 million events on castor) has been collected and is already under analysis. The CTB has been characterized by different phases with an incremental presence of sub-detectors modules and associated DAQ infrastructure, as well as incremental improvement of analysis tools for prompt data certification. The physics goals of the CTB have been defined in consultation with the physics coordinator, all the sub-detector representatives and the combined performance group representative. With all these indications, a detailed run plan day-by-day schedule was defined before the CTB start and was foll...

  16. Pixel-Tilecal-MDT Combined Test Beam

    CERN Multimedia

    B. Di Girolamo

    A test with many expectations When an additional week of running (from September 11th to 18th) was allocated for the test-beam, it was decided to give priority to a combined run with the participation of the Pixel, Tilecal and MDT sub-detectors. The integration of these three sub-detectors was possible as they all use the baseline (DAQ-1/EF based) DAQ for test beams (as reported in a previous e-news). The tests and the addition of a common trigger and busy were organized in a short timescale by experts from the three sub-detectors and DAQ/EF. The expectations were many; both looking for problems and finding solutions. The setup The setup, shown in the figure, consisted of the Pixel telescope normally used during the sub-detector tests, two Tilecal barrel modules, two Tilecal extended barrel modules, and six MDT barrel chambers. This fully occupied a length of some 30 meters in the H8 line of the SPS North Area. Each sub-detector used their own specialized front-end electronics. The data collected by modu...

  17. Spectral beam combining of multi-single emitters

    Science.gov (United States)

    Wang, Baohua; Guo, Weirong; Guo, Zhijie; Xu, Dan; Zhu, Jing; Zhang, Qiang; Yang, Thomas; Chen, Xiaohua

    2016-03-01

    Spectral beam combination expands the output power while keeps the beam quality of the combined beam almost the same as that of a single emitter. Spectral beam combination has been successfully achieved for high power fiber lasers, diode laser arrays and diode laser stacks. We have recently achieved the spectral beam combination of multiple single emitter diode lasers. Spatial beam combination and beam transformation are employed before beams from 25 single emitter diode lasers can be spectrally combined. An average output power about 220W, a spectral bandwidth less than 9 nm (95% energy), a beam quality similar to that of a single emitter and electro-optical conversion efficiency over 46% are achieved. In this paper, Rigorous Coupled Wave analysis is used to numerically evaluate the influence of emitter width, emitter pitch and focal length of transform lens on diffraction efficiency of the grating and spectral bandwidth. To assess the chance of catastrophic optical mirror damage (COMD), the optical power in the internal cavity of a free running emitter and the optical power in the grating external cavity of a wavelength locked emitter are theoretically analyzed. Advantages and disadvantages of spectral beam combination are concluded.

  18. Test Beam Coordination: 2003 ATLAS Combined Test Beam

    CERN Multimedia

    Di Girolamo, B.

    The 2003 Test Beam Period The 2003 Test Beam period has been very fruitful for ATLAS. In spite of several days lost because of the accelerator problems, ATLAS has been able to achieve many results: FCAL has completed the calibration program in H6 Tilecal has completed the calibration program in H8 Pixel has performed extensive studies with normal and high intensity beams (up to 1.4*108 hadrons/spill) SCT has completed a variety of studies with quite a high number of modules operated concurrently TRT has performed several studies at high, low and very low energy (first use of the new H8 beam in the range 1 to 9 GeV) Muons (MDT,RPC and TGC) have been operating a large setup for about 5 months. The almost final MDT ROD (MROD) has been integrated in the readout and the final trigger electronics for TGC and RPC has been tested and certified with normal beam and during dedicated 40 MHz beam periods. The TDAQ has exploited a new generation prototype successfully and the new Event Filter infrastructure f...

  19. Binary coherent beam combining with semiconductor TA at 705

    OpenAIRE

    Icaza Astiz, Yannik Alan de

    2009-01-01

    Projecte realitzat en col.laboració amb L'IFCO We present a coherent-beam-combining (CBC) experiment using a 795 nm diode laser as a technique to achieve more power by combining two beams. Two Gaussian beams are made to interfere while controlling polarization, amplitude and their relative phase, in a modified Mach-Zehnder interferometer coupled with a polarization interferometer. The output power is locked using a split detector, thus stabilizing its performance and the fin...

  20. New beam shaping: Matched filtering combined with GPC

    DEFF Research Database (Denmark)

    Glückstad, Jesper

    2010-01-01

    We adapt concepts frolll matched filtering 10 propose a method for generating rcconligurablc multiple beams. Combined with the Generalized Phase Contrast (GPC) technique, the proposed method coined mGPC can yield dynamically rcconfigurablc optical beam 31rdYS wilh high light efficiency for optica...... manipulation, high-speed sorting and other parallel spatial light applications r1].......We adapt concepts frolll matched filtering 10 propose a method for generating rcconligurablc multiple beams. Combined with the Generalized Phase Contrast (GPC) technique, the proposed method coined mGPC can yield dynamically rcconfigurablc optical beam 31rdYS wilh high light efficiency for optical...

  1. Coherent beam combiner for a high power laser

    Science.gov (United States)

    Dane, C. Brent; Hackel, Lloyd A.

    2002-01-01

    A phase conjugate laser mirror employing Brillouin-enhanced four wave mixing allows multiple independent laser apertures to be phase locked producing an array of diffraction-limited beams with no piston phase errors. The beam combiner has application in laser and optical systems requiring high average power, high pulse energy, and low beam divergence. A broad range of applications exist in laser systems for industrial processing, especially in the field of metal surface treatment and laser shot peening.

  2. Polarization/Spatial Combining of Laser-Diode Pump Beams

    Science.gov (United States)

    Gelsinger, Paul; Liu, Duncan

    2008-01-01

    A breadboard version of an optical beam combiner is depicted which make it possible to use the outputs of any or all of four multimode laser diodes to pump a non-planar ring oscillator (NPRO) laser. The output of each laser diode has a single-mode profile in the meridional plane containing an axis denoted the 'fast' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis and a narrower multimode profile in the orthogonal meridional plane, which contains an axis denoted the 'slow' axis. One of the purposes served by the beam-combining optics is to reduce the fast-axis numerical aperture (NA) of the laser-diode output to match the NA of the optical fiber. Along the slow axis, the unmodified laser-diode NA is already well matched to the fiber optic NA, so no further slow-axis beam shaping is needed. In this beam combiner, the laser-diode outputs are collimated by aspherical lenses, then half-wave plates and polarizing beam splitters are used to combine the four collimated beams into two beams. Spatial combination of the two beams and coupling into the optical fiber is effected by use of anamorphic prisms, mirrors, and a focusing lens. The anamorphic prisms are critical elements in the NA-matching scheme, in that they reduce the fast-axis beam width to 1/6 of its original values. Inasmuch as no slow-axis beam shaping is needed, the collimating and focusing lenses are matched for 1:1 iumaging. Because these lenses are well corrected for infinite conjugates the combiner offers diffraction-limited performance along both the fast and slow axes.

  3. Optimization of combined electron and photon beams for breast cancer

    International Nuclear Information System (INIS)

    Recently, intensity-modulated radiation therapy and modulated electron radiotherapy have gathered a growing interest for the treatment of breast and head and neck tumours. In this work, we carried out a study to combine electron and photon beams to achieve differential dose distributions for multiple target volumes simultaneously. A Monte Carlo based treatment planning system was investigated, which consists of a set of software tools to perform accurate dose calculation, treatment optimization, leaf sequencing and plan analysis. We compared breast treatment plans generated using this home-grown optimization and dose calculation software for different treatment techniques. Five different planning techniques have been developed for this study based on a standard photon beam whole breast treatment and an electron beam tumour bed cone down. Technique 1 includes two 6 MV tangential wedged photon beams followed by an anterior boost electron field. Technique 2 includes two 6 MV tangential intensity-modulated photon beams and the same boost electron field. Technique 3 optimizes two intensity-modulated photon beams based on a boost electron field. Technique 4 optimizes two intensity-modulated photon beams and the weight of the boost electron field. Technique 5 combines two intensity-modulated photon beams with an intensity-modulated electron field. Our results show that technique 2 can reduce hot spots both in the breast and the tumour bed compared to technique 1 (dose inhomogeneity is reduced from 34% to 28% for the target). Techniques 3, 4 and 5 can deliver a more homogeneous dose distribution to the target (with dose inhomogeneities for the target of 22%, 20% and 9%, respectively). In many cases techniques 3, 4 and 5 can reduce the dose to the lung and heart. It is concluded that combined photon and electron beam therapy may be advantageous for treating breast cancer compared to conventional treatment techniques using tangential wedged photon beams followed by a boost

  4. GRAVITY: a four-telescope beam combiner instrument for the VLTI

    CERN Document Server

    Gillessen, S; Perrin, G; Brandner, W; Straubmeier, C; Perraut, K; Amorim, A; Schöller, M; Araujo-Hauck, C; Bartko, H; Baumeister, H; Berger, J -P; Carvas, P; Cassaing, F; Chapron, F; Choquet, E; Clenet, Y; Collin, C; Eckart, A; Fedou, P; Fischer, S; Gendron, E; Genzel, R; Gitton, P; Gonte, F; Gräter, A; Haguenauer, P; Haug, M; Haubois, X; Henning, T; Hippler, S; Hofmann, R; Jocou, L; Kellner, S; Kervella, P; Klein, R; Kudryavtseva, N; Lacour, S; Lapeyrere, V; Laun, W; Lena, P; Lenzen, R; Lima, J; Moch, D; Moratschke, D; Moulin, T; Naranjo, V; Neumann, U; Nolot, A; Paumard, T; Pfuhl, O; Rabien, S; Ramos, J; Rees, J M; Rohloff, R -R; Rouan, D; Rousset, G; Sevin, A; Thiel, M; Wagner, K; Wiest, M; Yazici, S; Ziegler, D

    2010-01-01

    GRAVITY is an adaptive optics assisted Beam Combiner for the second generation VLTI instrumentation. The instrument will provide high-precision narrow-angle astrometry and phase-referenced interferometric imaging in the astronomical K-band for faint objects. We describe the wide range of science that will be tackled with this instrument, highlighting the unique capabilities of the VLTI in combination with GRAVITY. The most prominent goal is to observe highly relativistic motions of matter close to the event horizon of Sgr A*, the massive black hole at center of the Milky Way. We present the preliminary design that fulfils the requirements that follow from the key science drivers: It includes an integrated optics, 4-telescope, dual feed beam combiner operated in a cryogenic vessel; near-infrared wavefrontsensing adaptive optics; fringe-tracking on secondary sources within the field of view of the VLTI and a novel metrology concept. Simulations show that 10 {\\mu}as astrometry within few minutes is feasible for ...

  5. Mid-IR laser source using hollow waveguide beam combining

    Science.gov (United States)

    Elder, Ian F.; Thorne, Daniel H.; Lamb, Robert A.; Jenkins, R. M.

    2016-03-01

    Hollow waveguide technology is a route to efficient beam combining of multiple laser sources in a compact footprint. It is a technology appropriate for combining free-space or fibre-coupled beams generated by semiconductor, fibre or solidstate laser sources. This paper will present results of a breadboard mid-IR system comprising four laser sources combined using a hollow waveguide optical circuit. In this approach the individual dichroic beam combiner components are held in precision alignment slots in the hollow waveguide circuit and the different input wavelengths are guided between the components to a common output port. The hollow waveguide circuit is formed in the surface of a Macor (machinable glass-ceramic) substrate using precision CNC machining techniques. The hollow waveguides have fundamentally different propagation characteristics to solid core waveguides leading to transmission characteristics close to those of the atmosphere while still providing useful light guidance properties. The transmission efficiency and power handling of the hollow waveguide circuit can be designed to be very high across a broad waveband range. Three of the sources are quantum cascade lasers (QCLs), a semiconductor laser technology providing direct generation of midwave IR output. The combined beams provide 4.2 W of near diffraction-limited output co-boresighted to better than 20 µrad. High coupling efficiency into the waveguides is demonstrated, with negligible waveguide transmission losses. The overall transmission of the hollow waveguide beam combining optical circuit, weighted by the laser power at each wavelength, is 93%. This loss is dominated by the performance of the dichroic optics used to combine the beams.

  6. All-fiber 7x1 signal combiner for incoherent laser beam combining

    DEFF Research Database (Denmark)

    Noordegraaf, Danny; Maack, Martin D.; Skovgaard, Peter M. W.;

    2011-01-01

    We demonstrate an all-fiber 7x1 signal combiner for incoherent laser beam combining. This is a potential key component for reaching several kW of stabile laser output power. The combiner couples the output from 7 single-mode (SM) fiber lasers into a single multi-mode (MM) fiber. The input signal...

  7. Integrated optics for astronomical interferometry; 2, First laboratory white-light interferograms

    CERN Document Server

    Berger, J P; Kern, P; Malbet, M; Schanen-Duport, J P; Reynaud, P; Haguenauer, P; Benech, P

    1999-01-01

    We report first white-light interferograms obtained with an integrated optics beam combiner on a glass plate. These results demonstrate the feasability of single-mode interferometric beam combination with integrated optics technology presented and discussed in paper I. The demonstration is achieved in laboratory with off-the-shelves components coming from micro-sensor applications, not optimized for astronomical use. These two-telescope beam combiners made by ion exchange technique on glass substrate provide laboratory white-light interferograms simultaneously with photometric calibration. A dedicated interferometric workbench using optical fibers is set up to characterize these devices. Despite the rather low match of the component parameters to astronomical constraints, we obtain stable contrasts higher than 93% with a 1.54-\\micron laser source and up to 78% with a white-light source in the astronomical H band. Global throughput of 27% for a potassium ion exchange beam combiner and of 43% for a silver one a...

  8. Concept of the ESO-VLT Project-Beam Combination

    Science.gov (United States)

    Merkle, F.

    The optical configuration of the VLT is based on a linear array of 4 independently mounted 8 m telescopes. They can be operated either independently or in various combination schemes. In the latter case the light collected with the unit telescopes is fed via beam combination optics to the combined focus. The coherent combination path opens long baseline interferometry with a resolution span of approx. 0.5 marcsec in the blue to approx. 30 marcsec at 20 μm wavelength in the case of a 150 m baseline.

  9. Astronomical Cybersketching

    CERN Document Server

    Grego, Peter

    2009-01-01

    Outlines the techniques involved in making observational sketches and more detailed 'scientific' drawings of a wide variety of astronomical subjects using modern digital equipment; primarily PDAs and tablet PCs. This book also discusses about choosing hardware and software

  10. Combined electron beam and UV lithography in SU-8

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Thamdrup, Lasse Højlund; Mironov, Andrej; Kristensen, Anders

    2007-01-01

    We present combined electron beam and UV lithography (CEUL) in SU-8 as a fast and flexible lithographic technique for prototyping of functional polymer devices and pattern transfer applications. CEUL is a lithographic technique suitable for defining both micrometer and nanometer scale features in a...

  11. New Combined Electron-Beam Methods of Wastewater Purification

    International Nuclear Information System (INIS)

    The paper is a brief review of the results obtained with the participation of the authors from the study on combined electron-beam methods for purification of some wastewaters. The data on purification of wastewaters containing dyes or hydrogen peroxide and municipal wastewater in the aerosol flow are considered

  12. Laser beam combiner for Thomson scattering core LIDAR

    Energy Technology Data Exchange (ETDEWEB)

    Balboa, I.; Naylor, G.; Sirinelli, A.; Parsons, P.; Fessey, J.; Townsend, M.; Beurskens, M.; Conway, N.; Kempenaars, M.; Kirk, A. [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Huang, B. [Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Walsh, M. [Diagnostics Division, Department of CHD, ITER Organization, CS 90 046, Bulding 155/55, Route de Vinon, 13607 Saint-Paul-Lez-Durance Cedex (France); Flanagan, J.

    2010-10-15

    The light detection and ranging Thomson scattering (TS) diagnostic is advantageous since it only requires a single view port into the tokamak. This technique requires a short pulse laser at high energy, usually showing a limited repetition rate. Having multiple lasers will increase the repetition rate. This paper presents a scanning mirror as a laser beam combiner. Measurements of the position accuracy and jitter show that the pointing stability of the laser beam is within {+-}25 {mu}rad for over tens of seconds. A control feedback loop is implemented to demonstrate the long term stability. Such a system could be applied for ITER and JET.

  13. Astronomical Observatory

    Directory of Open Access Journals (Sweden)

    Mansi Khanna

    2014-03-01

    Full Text Available This photograph was taken at Jantar Mantar, one of India’s most famous astronomical observatories, located in Central Delhi. It was built in 1724 by Maharaja Jai Singh II of Jaipur, who then went on to build other observatories in Jaipur, Varanasi, and Mathura. It was used to make astronomical tables and predict movements of the planets and the sun. Its name is derived from yantra meaning instruments and mantar meaning formula.Due to the construction of several high rise buildings around the monument, it is no longer used for astronomical purposes. It however continues to be one of the biggest tourist attractions of the capital city. 

  14. Azimuthal multiple-beam interference effects with combinations of vortex beams.

    Science.gov (United States)

    Moreno, Ignacio; Davis, Jeffrey A; Womble-Dahl, Taylor; Cottrell, Don M

    2015-05-15

    We create a series of vortex beams consisting of positive and negative topological charges and develop a geometry where they interfere creating azimuthal multiple-beam interference effects. Usually the combination of two beams with opposite charges creates an azimuthal two-beam interference effect where the intensity varies sinusoidally with azimuthal angle. We combine several of these beams to create patterns where the interference becomes more sharply defined in the azimuthal direction and where destructive interference eliminates some of the intensity peaks. The process is complicated by the fact that the radii of the different vortex beams depend on the topological charge and the focal length of the Fourier lens. We generate a series of patterns where the different charges are focused with different focal lengths such that their radii agree. However to encode these, we encode patterns from the lower charges that have been Fresnel diffracted to the plane of the highest charge. These complicated patterns are encoded onto a liquid crystal display (LCD). Experimental results agree well with theory. PMID:26393734

  15. High power incoherent beam combining of fiber lasers based on a 7 × 1 all-fiber signal combiner

    Science.gov (United States)

    Zhou, Xuanfeng; Chen, Zilun; Wang, Zefeng; Hou, Jing; Xu, Xiaojun

    2016-05-01

    We report an experiment of incoherent beam combining based on a 7×1 all-fiber signal combiner with output power up to 6.08 kW. Properties of transmission efficiency and beam quality are analyzed by beam propagation method. Based on the calculative results, a 7×1 all-fiber signal combiner is fabricated. The handle power capacity is tested with average transmission efficiency of 98.9% and beam quality of M2≈10.

  16. Astronomical Ecosystems

    Science.gov (United States)

    Neuenschwander, D. E.; Finkenbinder, L. R.

    2004-05-01

    Just as quetzals and jaguars require specific ecological habitats to survive, so too must planets occupy a tightly constrained astronomical habitat to support life as we know it. With this theme in mind we relate the transferable features of our elementary astronomy course, "The Astronomical Basis of Life on Earth." Over the last five years, in a team-taught course that features a spring break field trip to Costa Rica, we have introduced astronomy through "astronomical ecosystems," emphasizing astronomical constraints on the prospects for life on Earth. Life requires energy, chemical elements, and long timescales, and we emphasize how cosmological, astrophysical, and geological realities, through stabilities and catastrophes, create and eliminate niches for biological life. The linkage between astronomy and biology gets immediate and personal: for example, studies in solar energy production are followed by hikes in the forest to examine the light-gathering strategies of photosynthetic organisms; a lesson on tides is conducted while standing up to our necks in one on a Pacific beach. Further linkages between astronomy and the human timescale concerns of biological diversity, cultural diversity, and environmental sustainability are natural and direct. Our experience of teaching "astronomy as habitat" strongly influences our "Astronomy 101" course in Oklahoma as well. This "inverted astrobiology" seems to transform our student's outlook, from the universe being something "out there" into something "we're in!" We thank the SNU Science Alumni support group "The Catalysts," and the SNU Quetzal Education and Research Center, San Gerardo de Dota, Costa Rica, for their support.

  17. Trigger and DAQ in the Combined Test Beam

    CERN Multimedia

    Dobson, M; Padilla, C

    2004-01-01

    Introduction During the Combined Test Beam the latest prototype of the ATLAS Trigger and DAQ system is being used to support the data taking of all the detectors. Further development of the TDAQ subsystems benefits from the direct experience given by the integration in the beam test. Support of detectors for the Combined Test Beam All ATLAS detectors need their own detector-specific DAQ development. The readout electronics is controlled by a Readout Driver (ROD), custom-built for each detector. The ROD receives data for events that are accepted by the first level trigger. The detector-specific part of the DAQ system needs to control the ROD and to respond to commands of the central DAQ (e.g. to "Start" a run). The ROD module then sends event data to a Readout System (ROS), a PC with special receiver modules/buffers. At this point the data enters the realm of the ATLAS DAQ and High Level Trigger system, constructed from Linux PCs connected with gigabit Ethernet networks. Most ATLAS detectors, representing s...

  18. Astronomical optics

    CERN Document Server

    Schroeder, Daniel J

    1988-01-01

    Written by a recognized expert in the field, this clearly presented, well-illustrated book provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic instruments used by astronomers of today.Key Features* Written by a recognized expert in the field* Provides both advanced level students and professionals with an authoritative, thorough presentation of the characteristics, including advantages and limitations, of telescopes and spectrographic i

  19. Simulation of phase noise for coherent beam combination

    Science.gov (United States)

    Hu, Qi-qi; Huang, Zhi-meng; Tang, Xuan; Luo, Yong-quan; Zhang, Da-yong

    2015-02-01

    Active coherent beam combination has been a hot area of research for several years. Particular algorithm module is used to stabilize the phase difference between beamlets, and make them coherent. The phase noise increases with the raising power of laser output. Under low power condition, we simulate the phase noise of high power laser amplifier by the Arbitrary Function Generators (AFGs), and send them to the phase modulators to destabilize the phase, to test the performance of the phase lock algorithm. The experimental results show the feasibility.

  20. Mutually incoherent beam combining through optical parametric amplification

    International Nuclear Information System (INIS)

    This work deals with a technique of combination of coherent beams: Optical Parametric Amplification (OPA) with Multiple Pumps. This technique is used to instantly transfer the energy of several pumps on one beam, without energy storage and thus avoiding thermal effects in the amplifying media. It can be useful to combine energy of numerous fiber lasers and to amplify with a high repetition rate very high energy lasers or broadband pulses. With a numerical and experimental study using BBO and LBO as nonlinear crystal, we determine how to dispose the pumps around the signal and the corresponding angular tolerances of such set up. Then we focus our attention on recombining mechanisms between a pump and a non-corresponding idler. We demonstrate experimentally that these cascading effects may decrease the spatial and spectral quality of the amplified signal, and that these phenomena can be avoided with a minimum angle between the different pumps. A novel modelling of multi-pumps OPA links these cascading effects to the gratings generated by the interaction between the pumps. The last part presents a 5 pump OPA experiment. We achieve a pump-to-signal efficiency of 27% and so that a signal more powerful than each pump is obtained. (author)

  1. Combined performance studies for electrons at the 2004 ATLAS combined test-beam

    International Nuclear Information System (INIS)

    In 2004 at the ATLAS (A Toroidal LHC ApparatuS) combined test beam, one slice of the ATLAS barrel detector (including an Inner Detector set-up and the Liquid Argon calorimeter) was exposed to particles from the H8 SPS beam line at CERN. It was the first occasion to test the combined electron performance of ATLAS. This paper presents results obtained for the momentum measurement p with the Inner Detector and for the performance of the electron measurement with the LAr calorimeter (energy E linearity and resolution) in the presence of a magnetic field in the Inner Detector for momenta ranging from 20 GeV/c to 100 GeV/c. Furthermore the particle identification capabilities of the Transition Radiation Tracker, Bremsstrahlungs-recovery algorithms relying on the LAr calorimeter and results obtained for the E/p ratio and a way how to extract scale parameters will be discussed.

  2. Numerical analysis of the beam quality and spectrum of wavelength-beam-combined laser diode arrays

    Science.gov (United States)

    Tang, Xuan; Wang, Xiao-Jun; Ke, Wei-Wei

    2015-02-01

    In this paper, a numerical model is presented to simulation the performance of the wavelength-beam-combined laser diode arrays (LDA) system. The eigen mode expansion method is used to describe the two-dimensional optical amplification and the strength of field feedback of external cavity. To describe the mode competition in laser diodes, the gain saturation effect is considered. The two-dimension distributions of the carrier concentration, recombination rates, and optical gain are calculated for solving the laser dynamic equation. The Fresnel integration, grating equation and mode overlap integration are used to obtain the feedback coefficient of extent cavity diffraction. Quantum noise is considered to evaluate the spectral linewidth of semiconductor laser. Based on the numerical model, the impact of the mutual optical feedback on the beam quality and spectrum of the LDA is present and analysis.

  3. A survey of beam-combining technologies for laser space power transmission

    Science.gov (United States)

    Kwon, J. H.; Williams, M. D.; Lee, J. H.

    1988-01-01

    The combination of laser beams holds much promise for obtaining powerful beams. Methods are surveyed for beam combination (coherent and incoherent) and two of them are identified as the most effective means for achieving high power transmission in space. The two methods as applied to laser diode arrays are analyzed, and potentially productive work areas for the advancement of technology are delineated.

  4. Off-Axis Astigmatic Gaussian Beam Combination Beyond the Paraxial Approximation

    Institute of Scientific and Technical Information of China (English)

    GAO Zeng-Hui; L(U) Bai-Da

    2007-01-01

    Taking the off-axis astigmatic Gaussian beam combination as an example, the beam-combination concept is extended to the nonparaxial regime. The closed-form propagation expressions for coherent and incoherent combinations of nonparaxial off-axis astigmatic Gaussian beams with rectangular geometry are derived and illustrated with numerical examples. It is shown that the intensity distributions of the resulting beam depend on the combination scheme and beam parameters in general, and in the paraxial approximation (i.e., for the small f-parameter)our results reduce to the paraxial ones.

  5. Synergistic effects obtained by combined electron beam and microwave irradiation

    International Nuclear Information System (INIS)

    A new method based on microwave energy addition to accelerated electron beam energy for material processing was developed. The main idea of this work was to combine the advantages of both electron beam (EB) irradiation and microwave (MW) irradiation, i.e. EB high irradiation efficiency and MW high selectivity and volumetric heating, for material processing. The first expected and obtained result was the decrease of the required EB absorbed dose. Thus, the ionizing radiation costs could be reduced and the application of low intensity EB accelerators will become very economically attractive in the material-processing field. Another expected and obtained result was the improvement of material properties. A special designed facility consisting of an EB accelerator of 5.5 MeV and a MW source of 2.45 GHz and 1.6 kW that performs combined EB and MW irradiation is presented. There are three fields of interest under our investigation for application of combined EB and MW irradiation: environmental waste treatment (sewage sludge, flue gases), sterilization (food residuals, hospital wastes) and food quality and safety. Both, EB (ionizing radiation) and MW (non-ionizing) material processing are based on the radiation ability to alter physical and chemical properties of materials. Irradiation with electron beams was put forth as a very effective method for material processing because can produce ions, electrons, and free radicals at any temperature in the solid, liquid and gas. EB processes are very effective for material processing but the required absorbed dose is still high for pollutants removal, sterilization, vulcanization, etc. MW processing of materials is a relatively new technology that provides new approaches to improve the physical properties of materials and to produce new materials and microstructures that cannot be achieved by other methods. MW processes are less effective for material processing than EB processes but the cost of microwave systems is considerably

  6. 'OHANA-Iki: a test-bed for the 'OHANA beam combiner and delay line at CFHT

    Science.gov (United States)

    Baril, Marc; Lai, Olivier; Zahariade, George; Bouchacourt, Flora; Perrin, Guy; Fedou, Pierre; Woillez, Julien

    2010-07-01

    The possibility of interferometrically coupling large telescopes using single-mode (SM) fibers is a very attractive one, especially at topographically complex and culturally sensitive astronomical observing sites such as the Mauna-Kea summit in Hawaii. The 'OHANA project (Optical Hawaiian Array for Nanoradian Astronomy) aims to link up seven of the large telescopes on Mauna-Kea. The concept of using SM fiber links for interferometry has been demonstrated using the two W. M. Keck telescopes. A beam-combiner and optical delay line has been installed at the Canada France Hawaii Telescope (CFHT) to link up Gemini North and CFHT. In order to test the CFHT beam-combiner without making use of CFHT and Gemini observing time, the idea of using two small, 20 cm aperture telescopes to inject starlight into the 'Ohana interferometer fibers was devised. This project, dubbed 'OHANA-Iki, is also exploring the concept of a "soft" optical interferometer, specifically one in which the telescopes are easily movable and would not require the heavy, fixed infrastructure found in conventional freespace interferometers such as the VLTI.

  7. Combined external beam and intraluminal radiotherapy for irresectable Klatskin tumors

    Energy Technology Data Exchange (ETDEWEB)

    Schleicher, U.M. [Klinik fuer Strahlentherapie, Technische Hochschule Aachen (Germany); Staatz, G. [Klinik fuer Radiologische Diagnostik, Technische Hochschule Aachen (Germany); Alzen, G. [Klinik fuer Radiologische Diagnostik, Technische Hochschule Aachen (Germany); Abt. Kinderradiologie, Giessen Univ. (Germany); Andreopoulos, D. [Klinik fuer Strahlentherapie, Technische Hochschule Aachen (Germany); BOC Oncology Centre, Nikosia (Cyprus)

    2002-12-01

    Background: In most cases of proximal cholangiocarcinoma, curative surgery is not possible. Radiotherapy can be used for palliative treatment. We report our experience with combined external beam and intraluminal radiotherapy of advanced Klatskin's tumors. Patients and Methods: 30 patients were treated for extrahepatic proximal bile duct cancer. Our schedule consisted for external beam radiotherapy (median dose 30 Gy) and a high-dose-rate brachytherapy boost (median dose 40 Gy) delivered in four or five fractions, which could be applied completely in twelve of our patients. 15 patients in the brachytherapy and nine patients in the non-brachytherapy group received additional low-dose chemotherapy with 5-fluorouracil. Results: The brachytherapy boost dose improved the effect of external beam radiotherapy by increasing survival from a median of 3.9 months in the non-brachytherapy group to 9.1 months in the brachytherapy group. The effect was obvious in patients receiving a brachytherapy dose above 30 Gy, and in those without jaundice at the beginning of radiotherapy (p<0.05). Conclusions: The poor prognosis in patients with advanced Klatskin's tumors may be improved by combination therapy, with the role of brachytherapy and chemotherapy still to be defined. Our results suggest that patients without jaundice should be offered brachytherapy, and that a full dose of more than 30 Gy should be applied. (orig.) [German] Hintergrund: Bei den meisten Patienten mit proximalen Cholangiokarzinomen ist eine kurative Operation nicht mehr moeglich. Im Rahmen der Palliativbehandlung kann die Strahlentherapie eingesetzt werden. Wir berichten ueber unsere Erfahrungen mit der Kombination aus perkutaner und intraluminaler Strahlentherapie fortgeschrittener Klatskin-Tumoren. Patienten und Methode: 30 Patienten wurden wegen extrahepatischer proximaler Gallengangskarzinome behandelt. Unser Therapieschema umfasste eine perkutane Strahlentherapie (mediane Dosis: 30 Gy) sowie einen

  8. Investigation of fish otoliths by combined ion beam analysis

    International Nuclear Information System (INIS)

    Complete text of publication follows. This work was implemented within the framework of the Hungarian Ion beam Physics Platform (http://hipp.atomki.hu/). Otoliths are small structures, 'the ear stones' of a fish, and are used to detect acceleration and orientation. They are composed of a combination of protein matrix and calcium carbonate (CaCO3) forming aragonite micro crystals. They have an annually deposited layered conformation with a microstructure corresponding to the seasonal and daily increments. Trace elements, such as Sr, Zn, Fe etc., are also incorporated into the otolith from the environment and the nutrition. The elemental distribution of the otolith of fresh water fish burbot (Lota lota L.) collected in Hungary was measured with Elastic Recoil Detection Analysis (ERDA), Rutherford backscattering spectrometry (RBS) and Particle Induced X-ray Emission (PIXE) at the Nuclear Microprobe Facility of HAS ATOMKI. The spatial 3D structure of the otolith could be observed with a sub-micrometer resolution. It is confirmed that the aragonite micro-crystals are covered by an organic layer and there are some protein rich regions in the otolith, too. By applying the RBSMAST code developed for RBS on macroscopic structure, it was proven that the orientation of the needle shaped aragonite crystals is considerably different at adjacent locations in the otolith. The organic and inorganic component of the otolith could be set apart in the depth selective hydrogen and calcium maps derived by micro- ERDA and micro-RBS. Similar structural analysis could be done near the surface by combining the C, O and Ca elemental maps determined by micro-PIXE measurements. It was observed that the trace metal Zn is bound to the protein component. Acknowledgements This work was partially supported by the Hungarian OTKA Grant No. T046238 and the EU cofunded Economic Competitiveness Operative Programme (GVOP-3.2.1.-2004-04-0402/3.0)

  9. Combined analyses of ion beam synthesized layers in porous silicon

    International Nuclear Information System (INIS)

    High dose ion implantation was used to form polycrystalline silicide films on porous silicon with different native concentrations of light impurities (C and O). Porous silicon layers several μm thick were implanted with 170 KeV Cr+ ions to fluences of 3x10'17 ions/cm2 both at room temperature and 450 oC. Similar samples were implanted with 100 keV Co+ ions to fluences of 2x1017 ions/cm2 at room temperature and 350 oC and 450 oC. The formed silicide compounds were studied by Rutherford backscattering spectrometry, elastic recoil detection, glancing incidence X-ray diffraction, and four point-probe sheet resistance measurements. Selected Co implanted samples were analysed by cross-section transmission electron microscopy. Results show that the light impurities were partially expelled from the forming silicide layer. Combining cross-section transmission electron microscopy with ion beam methods it was possible to show that, in the implanted region, the porous structure collapses and densities during implantation, but the underlying porous silicon remains intact. The layer structure as well as the quality and type of the formed silicide, were found to depend on the original impurity level, implantation temperature, and annealing. (author)

  10. Influence of turbulent atmosphere on the far-field coherent combined beam quality

    Institute of Scientific and Technical Information of China (English)

    Pu Zhou; Zejin Liu; Xiaojun Xu; Xiaolin Wang; Xiao Li; Zilun Chen

    2008-01-01

    Propagation of coherent combined laser beams in turbulent atmosphere is numerically studied based on the extended Huygens-Fresnel principle. By choosing beam propagation factor (BPF) and beam quality factor (BQ) to characterize the far-field irradiance distribution properties, the influence of turbulence on far-field coherent combined beam quality is studied in detail. The investigation reveals that with the coherence length decreasing, the irradiance distribution pattern evolves from typical non-Gaussian shape with multiple side-lobes into Gaussian shape which is seen in the incoherent combining case. In weak turbulent atmosphere, the far-field beam quality suffers less when the 1aser array gets more compact and operates at a longer wavelength. In strong turbulent atmosphere, the far-field beam quality degrades into the incoherent combining case without any relationship with the fill factor and laser wavelength.

  11. Free-Space Nonlinear Beam Combining Towards Filamentation

    CERN Document Server

    Rostami, Shermineh; Kepler, Daniel; Baudelet, Matthieu; Litchinitser, Natalia M; Richardson, Martin

    2016-01-01

    Multi-filamentation opens new degrees of freedom for manipulating electromagnetic waves in air. However, without control, multiple filament interactions, including attraction, repulsion or fusion often result in formation of complex disordered filament distributions. Moreover, high power beams conventionally used in multi-filament formation experiments often cause significant surface damage. The growing number of applications for laser filaments requires fine control of their formation and propagation. We demonstrate, experimentally and theoretically, that the attraction and fusion of ultrashort beams with initial powers below the critical value enable the eventual formation of a filament downstream. Filament formation is delayed to a predetermined distance in space, avoiding optical damage to external beam optics while still enabling robust filaments with controllable properties as if formed from a single high power beam. This paradigm introduces new opportunities for filament engineering eliminating the nee...

  12. Electron-beam-sustained discharge revisited - light emission from combined electron beam and microwave excited argon at atmospheric pressure

    CERN Document Server

    Dandl, T; Neumeier, A; Wieser, J; Ulrich, A

    2015-01-01

    A novel kind of electron beam sustained discharge is presented in which a 12keV electron beam is combined with a 2.45GHz microwave power to excite argon gas at atmospheric pressure in a continuous mode of operation. Optical emission spectroscopy is performed over a wide wavelength range from the vacuum ultraviolet (VUV) to the near infrared (NIR). Several effects which modify the emission spectra compared to sole electron beam excitation are observed and interpreted by the changing plasma parameters such as electron density, electron temperature and gas temperature.

  13. Combining Generalized Phase Contrast with matched filtering into a versatile beam shaping approach

    DEFF Research Database (Denmark)

    Glückstad, Jesper; Palima, Darwin

    2010-01-01

    We adapt concepts from matched filtering to propose a method for generating reconfigurable multiple beams. Combined with the Generalized Phase Contrast (GPC) technique, the proposed method coined mGPC can yield dynamically reconfigurable optical beam arrays with high light efficiency for optical ...... manipulation, high-speed sorting and other parallel spatial light applications [1].......We adapt concepts from matched filtering to propose a method for generating reconfigurable multiple beams. Combined with the Generalized Phase Contrast (GPC) technique, the proposed method coined mGPC can yield dynamically reconfigurable optical beam arrays with high light efficiency for optical...

  14. Combining generalized phase contrast with matched filtering into a versatile beam shaping system

    DEFF Research Database (Denmark)

    Glückstad, Jesper

    2009-01-01

    We adapt concepts from matched filtering to propose a method for generating reconfigurable multiple beams. Combined with the Generalized Phase Contrast (GPC) technique, the proposed method coined mGPC can yield dynamically reconfigurable optical beam arrays with high light efficiency for optical ...... manipulation, high-speed sorting and other parallel spatial light applications.......We adapt concepts from matched filtering to propose a method for generating reconfigurable multiple beams. Combined with the Generalized Phase Contrast (GPC) technique, the proposed method coined mGPC can yield dynamically reconfigurable optical beam arrays with high light efficiency for optical...

  15. Analytical treatment of the nonlinear electron cloud effect and the combined effects with beam-beam and space charge nonlinear forces in storage rings

    Institute of Scientific and Technical Information of China (English)

    GAO Jie

    2009-01-01

    In this paper we treat first some nonlinear beam dynamics problems in storage rings, such as beam dynamic apertures due to magnetic multipoles, wiggles, beam-beam effects, nonlinear space charge effect, and then nonlinear electron cloud effect combined with beam-beam and space charge effects, analytically. This analytical treatment is applied to BEPC Ⅱ. The corresponding analytical expressions developed in this paper are useful both in understanding the physics behind these problems and also in making practical quick hand estimations.

  16. Biographical encyclopedia of astronomers

    CERN Document Server

    Trimble, Virginia; Williams, Thomas; Bracher, Katherine; Jarrell, Richard; Marché, Jordan; Palmeri, JoAnn; Green, Daniel

    2014-01-01

    The Biographical Encyclopedia of Astronomers is a unique and valuable resource for historians and astronomers alike. It includes approx. 1850 biographical sketches on astronomers from antiquity to modern times. It is the collective work of 430 authors edited by an editorial board of 8 historians and astronomers. This reference provides biographical information on astronomers and cosmologists by utilizing contemporary historical scholarship. The fully corrected and updated second edition adds approximately 300 biographical sketches. Based on ongoing research and feedback from the community, the new entries will fill gaps and provide expansions. In addition, greater emphasis on Russo phone astronomers and radio astronomers is given. Individual entries vary from 100 to 1500 words, including the likes of the super luminaries such as Newton and Einstein, as well as lesser-known astronomers like Galileo's acolyte, Mario Guiducci.

  17. Super-intense femtosecond multichannel laser system with coherent beam combining

    Science.gov (United States)

    Bagayev, S. N.; Trunov, V. I.; Pestryakov, E. V.; Frolov, S. A.; Leshchenko, V. E.; Kokh, A. E.; Vasiliev, V. A.

    2014-07-01

    The conceptual design of ultra-high intensity multichannel laser system with coherent beam combining is presented. Design of 1 PW and 10 PW laser channels with pulse repetition rate of 10 Hz based on optical parametric amplification in LBO crystals is considered. Requirements of the most critical pulse parameters for high efficiency coherent beam combining and their dependence on the number of channels is analyzed. Experimentally coherent beam combining of parametrically amplified compressed femtosecond pulses is demonstrated for the first time. Original two-loop relative timing jitter active stabilization scheme is proposed and experimentally investigated. 97% coherent beam combining efficiency is achieved with 110 as relative timing jitter.

  18. Narrow linewidth operation of a spectral beam combined diode laser bar.

    Science.gov (United States)

    Zhu, Zhanda; Jiang, Menghua; Cheng, Siqi; Hui, Yongling; Lei, Hong; Li, Qiang

    2016-04-20

    Our experiment is expected to provide an approach for realizing ultranarrow linewidth for a spectral beam combined diode laser bar. The beams of a diode laser bar are combined in a fast axis after a beam transformation system. With the help of relay optics and a transform lens with a long focal length of 1.5 m, the whole wavelength of a spectral combined laser bar can be narrowed down to 0.48 nm from more than 10 nm. We have achieved 56.7 W cw from a 19-element single bar with an M2 of 1.4  (in horizontal direction)×11.6  (in vertical direction). These parameters are good evidence that all the beams from the diode laser bar are combined together to increase the brightness. PMID:27140101

  19. High-power beam combining: a step to a future laser weapon system

    Science.gov (United States)

    Protz, Rudolf; Zoz, Jürgen; Geidek, Franz; Dietrich, Stephan; Fall, Michael

    2012-11-01

    Due to the enormous progress in the field of high-power fiber lasers during the last years commercial industrial fiber lasers are now available, which deliver a near-diffraction limited beam with power levels up to10kW. For the realization of a future laser weapon system, which can be used for Counter-RAM or similar air defence applications, a laser source with a beam power at the level of 100kW or more is required. At MBDA Germany the concept for a high-energy laser weapon system is investigated, which is based on such existing industrial laser sources as mentioned before. A number of individual high-power fiber laser beams are combined together, using one common beam director telescope. By this "geometric" beam coupling scheme, sufficient laser beam power for an operational laser weapon system can be achieved. The individual beams from the different lasers are steered by servo-loops, using fast tip-tilt mirrors. This principle enables the concentration of the total laser beam power at the common focal point on a distant target, also allowing fine tracking of target movements and first order compensation of turbulence effects on laser beam propagation. The proposed beam combination concept was demonstrated using several experimental set-ups. Different experiments were performed, to investigate laser beam target interaction and target fine tracking also at large distances. Content and results of these investigations are reported. An example for the lay-out of an Air Defence High Energy Laser Weapon (ADHELW ) is given. It can be concluded, that geometric high-power beam combining is an important step for the realization of a laser weapon system in the near future.

  20. Combined in-beam gamma-ray and conversion electron spectroscopy with radioactive ion beams

    Directory of Open Access Journals (Sweden)

    Konki J.

    2013-12-01

    Full Text Available In-beam gamma-ray and electron spectroscopy have been widely used as tools to study the broad variety of phenomena in nuclear structure. The SPEDE spectrometer is a new device to be used in conjunction with the MINIBALL germanium detector array to enable the detection of internal conversion electrons in coincidence with gamma rays from de-exciting nuclei in radioactive ion beam experiments at the upcoming HIE-ISOLDE facility at CERN, Switzerland. Geant4 simulations were carried out in order to optimise the design and segmentation of the silicon detector to achieve good energy resolution and performance.

  1. Coherent beam combination of Yb:YAG single-crystal rod amplifiers.

    Science.gov (United States)

    Kienel, Marco; Müller, Michael; Demmler, Stefan; Rothhardt, Jan; Klenke, Arno; Eidam, Tino; Limpert, Jens; Tünnermann, Andreas

    2014-06-01

    Coherent combination of ultrashort laser pulses emitted from spatially separated amplifiers is a promising power-scaling technique for ultrafast laser systems. It has been successfully applied to fiber amplifiers, since guidance of the signal provides the advantage of an excellent beam quality and straightforward superposition of beams as compared to bulk-type amplifier implementations. Herein we demonstrate, for the first time to our knowledge, a two-channel combining scheme employing Yb:YAG single-crystal rod amplifiers as an energy booster in a fiber chirped-pulse amplification system. In this proof-of-principle experiment, combined and compressed pulses with a duration of 695 fs and an energy of 3 mJ (3.7 GW of peak power) are obtained. The combining efficiency is as high as 94% and the beam quality of the combined output is characterized by a measured M2-value of 1.2. PMID:24876032

  2. Wavelength beam combining of a 980-nm tapered diode laser bar in an external cavity

    Science.gov (United States)

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Thestrup, Birgitte

    2010-04-01

    High power diode lasers are used in a large number of applications. A limiting factor for more widespread use of broad area lasers is the poor beam quality. Gain guided tapered diode lasers are ideal candidates for industrial applications that demands watt level output power with good beam quality. By adapting a bar geometry, the output power could be scaled even up to several tens of watts. Unfortunately, the high divergence which is a characteristic feature of the bar geometry could lead to a degradation of the overall beam quality of the laser bar. However, spectral beam combining is an effective solution for preserving the beam quality of the bar in the range of that of a single emitter and at the same time, enabling the power scaling. We report spectral beam combining applied to a 12 emitter tapered laser bar at 980 nm. The external cavity has been designed for a wavelength separation of 4.0 nm between the emitters. An output power of 9 W has been achieved at an operating current of 30 A. The combined beam had an M2 value (1/e2) of 5.3 along the slow axis which is comparable to that of a single tapered emitter on the laser bar. The overall beam combining efficiency was measured to be 63%. The output spectrum of the individual emitters was narrowed considerably. In the free running mode, the individual emitters displayed a broad spectrum of the order of 0.5-1.0 nm while the spectral width has been reduced to 30-100 pm in the spectral beam combining mode.

  3. Beam combined laser fusion driver using stimulated Brillouin scattering phase conjugation mirrors

    International Nuclear Information System (INIS)

    The beam combination method using stimulated Brillouin scattering phase conjugate mirrors (SBS-PCMs) is a promising technique for realizing the laser fusion driver with an ultrahigh energy/power laser system operating with a high repetition rate over 10 Hz. For realizing the beam combined laser system, it is necessary to lock/control the phases of SBS beams. In our previous papers, the new phase control technique using the self-generated density modulation was proposed, and its principle has been demonstrated experimentally. However, all the previous works were done without amplifiers. In this work, it has been demonstrated that the phase is stabilized with λ /51 fluctuation by standard deviation during 5,000 laser shots (500 sec.) in the two-beam combination system with amplifiers with 200 mJ total output energy and 10 Hz repletion rate. (author)

  4. Combining gigawatt level X-band high power microwave beams with an overmoded circular waveguide diplexer

    International Nuclear Information System (INIS)

    The high power microwave (HPM) beam combining results at X-band with an overmoded waveguide diplexer are presented. As the key device for the beam combining experiments, the diplexer is designed, fabricated, and tested. Then the beam combining experiments under short and long pulses are performed at HPM source, respectively. The experiment results reveal that short and long pulse HPM beams have been successfully operated without microwave breakdown at 3-GW with pulse duration of 25 ns and 1.3-GW with pulse duration of 96 ns. According to the experiments, conservative breakdown thresholds for the diplexer are concluded to be 800 kV/cm and 550 kV/cm, respectively, under the short and long pulse HPM conditions

  5. Ultrarelativistic laser systems based on coherent beam combining

    Science.gov (United States)

    Bagayev, S. N.; Trunov, V. I.; Pestryakov, E. V.; Frolov, S. A.; Leschenko, V. E.; Kirpichnikov, A. V.; Kokh, A. E.; Petrov, V. V.; Vasiliev, V. A.

    2012-07-01

    Conceptual design for femtosecond laser system of exawatt class, based on multi-channel amplifier and coherent field combining of petawatt amplifier channels with phase-frequency controlled radiation by optical clock are discussed. The scheme of start petawatt level few-cycle laser system with stable phase-frequency parameters determinated by the accuracy of the optical standard based on parametric amplification in big-size LBO crystals pumped by picosecond pulses is analyzed.

  6. The integrated optics beam combiner assembly of the GRAVITY/VLTI instrument

    Science.gov (United States)

    Jocou, L.; Perraut, K.; Nolot, A.; Moulin, T.; Magnard, Y.; Labeye, P.; Lapras, V.; Eisenhauer, F.; Perrin, G.; Amorim, A.; Brandner, W.; Straubmeier, C.

    2012-07-01

    Gravity aims at enhancing infrared imaging at VLTI to significantly improve our understanding of the physical processes related to gravitation and accretion within compact objects. With its fiber-fed integrated optics, infrared wavefront sensors, fringe tracker, beam stabilization and a novel metrology concept, GRAVITY will push the sensitivity and accuracy of astrometry and interferometric imaging far beyond what is offered today. Four telescopes will be combined in dual feed in the K band providing precision astrometry of order 10 micro-arcseconds, and imaging with 4- milliarcsecond resolution. The fringe tracker and the scientific instrument host an identical integrated optics beam combiner made by silica-on-silicon etching technology that is put inside a cryogenic vessel and cooled down to 200K to reduce thermal background and increase sensitivity. This paper gives the design of the integrated beam combiner and of its fibered array that allows feeding the combiner with stellar light. Lab measurement of spectral throughput and interferometric performance for beam combiners made by Flame Hydrolysis Deposition and by Plasma-Enhanced Chemical Vapor Deposition (PECVD) are given. The procedure to glue together the beam combiner and its fibered array is described as well as the tests to validate the performance and the ageing effects at low temperature. Finally the thermal analysis and the eigen-frequency study of the whole device are presented.

  7. VISION: Next Generation Beam Combiner for the Navy Precision Optical Interferometer

    Science.gov (United States)

    Garcia, Eugenio; van Belle, G.; Muterspaugh, M. W.; Swihart, S.

    2014-01-01

    The Visible Imaging System for Interferometric Observations at NPOI (VISION) is a versatile beam combiner for the Navy Precision Optical Interferometer (NPOI). VISION is a fiber-optics based beam combiner that can coherently combine light from up to 6 telescopes simultaneously using an image-plane combination scheme. VISION was inspired by the Michigan Infrared Combiner (MIRC) for the CHARA array - but VISION operates at optical wavelengths. With planned resolutions of VISION will be used to reconstruct multi-pixel time-varying images of evolved (luminosity class I-III) stars - in other words, movies of stellar surface variations. VISION’s visible light beam combination will be able to uniquely characterize surface features of stars less accessible at infrared wavelengths by interferometers such as CHARA. The “classic” beam combiner for NPOI employs a pupil-plane image combination which has visibility amplitude and closure phase precisions of 5-20% and 1-10 degrees respectively.VISION features a photometric camera for calibrations, spatial filtering from single mode fibers, and negligible read noise with a modern Andor Ixon CCD. These features will enable a factor of 10 improvement in visibility amplitude and closure phase precisions.

  8. Wavelength beam combining of a 980-nm tapered diode laser bar in an external cavity

    DEFF Research Database (Denmark)

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Thestrup Nielsen, Birgitte

    2010-01-01

    4.0 nm between the emitters. An output power of 9 W has been achieved at an operating current of 30 A. The combined beam had an M2 value (1/e2) of 5.3 along the slow axis which is comparable to that of a single tapered emitter on the laser bar. The overall beam combining efficiency was measured to......High power diode lasers are used in a large number of applications. A limiting factor for more widespread use of broad area lasers is the poor beam quality. Gain guided tapered diode lasers are ideal candidates for industrial applications that demands watt level output power with good beam quality...

  9. 16 W output power by high-efficient spectral beam combining of DBR-tapered diode lasers

    OpenAIRE

    Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin; Hasler, Karl-Heinz; Sumpf, Bernd; Erbert, Götz; Andersen, Peter E.; Petersen, Paul Michael

    2011-01-01

    Up to 16 W output power has been obtained using spectral beam combining of two 1063 nm DBR-tapered diode lasers. Using a reflecting volume Bragg grating, a combining efficiency as high as 93.7% is achieved, resulting in a single beam with high spatial coherence. The result represents the highest output power achieved by spectral beam combining of two single element tapered diode lasers. Since spectral beam combining does not affect beam propagation parameters, M2-values of 1.8 (fast axis) and...

  10. Versatile AFM setup combined with micro-focused X-ray beam

    CERN Document Server

    Slobodskyy, T; Tholapi, R; Liefeith, L; Fester, M; Sprung, M; Hansen, W

    2015-01-01

    Micro-focused X-ray beams produced by third generation synchrotron sources offer new perspective of studying strains and processes at nanoscale. Atomic force microscope setup combined with a micro-focused synchrotron beam allows precise positioning and nanomanipulation of nanostructures under illumination. In this paper, we report on integration of a portable commercial atomic force microscope setup into a hard X-ray synchrotron beamline. Details of design, sample alignment procedure and performance of the setup are presented.

  11. Polarization beam combination technique for gain saturation effect compensation in high-energy systems

    Science.gov (United States)

    Chen, Junchi; Peng, Yujie; Su, Hongpeng; Leng, Yuxin

    2016-06-01

    To compensate for the gain saturation effect in the high-energy laser amplifier, a modified polarization beam combination (PBC) method is introduced to reshape temporal waveform of the injected laser pulse to obtain a controlled high-energy laser pulse shape after amplification. One linearly polarized beam is divided into two orthogonal polarized beams, which spatially recombine together collinearly after propagating different optical paths with relative time delay in PBC structure. The obtained beam with polarization direction being rotated by the following half wave plate is divided and combined again to reform a new beam in another modified polarization beam structure. The reformed beam is injected into three cascaded laser amplifiers. The amplified pulse shape can be controlled by the incident pulse shape and amplifier gain, which is agreeable to the simulation by the Frank-Nodvik equations. Based on the simple method, the various temporal waveform of output pulse with tunable 7 to 20 ns pulse duration can be obtained without interferometric fringes.

  12. Euler: Genius Blind Astronomer Mathematician

    OpenAIRE

    Musielak, Dora

    2014-01-01

    Leonhard Euler, the most prolific mathematician in history, contributed to advance a wide spectrum of topics in celestial mechanics. At the Saint Petersburg Observatory, Euler observed sunspots and tracked the movements of the Moon. Combining astronomical observations with his own mathematical genius, he determined the orbits of planets and comets. Euler laid the foundations of the methods of planetary perturbations and solved many of the Newtonian mechanics problems of the eighteenth century...

  13. Auto Adjusting Astronomical Telescope

    OpenAIRE

    Rohit R. Ghalsasi; Prof. N. D. Dhoot

    2014-01-01

    Astronomical telescope is powerful and basic tool for star or celestial observation. Here we proposed integrated system using Raspberry Pi for auto adjusting astronomical telescope. This integrated circuit helps to control stellar monitoring, stellar targeting, and tracking functions of telescope. Astro compass gives the direction of the celestial objects.

  14. Auto Adjusting Astronomical Telescope

    Directory of Open Access Journals (Sweden)

    Rohit R. Ghalsasi

    2014-04-01

    Full Text Available Astronomical telescope is powerful and basic tool for star or celestial observation. Here we proposed integrated system using Raspberry Pi for auto adjusting astronomical telescope. This integrated circuit helps to control stellar monitoring, stellar targeting, and tracking functions of telescope. Astro compass gives the direction of the celestial objects.

  15. The polarization-based collimated beam combiner and the proposed NOVA fringe tracker (NFT) for the VLTI

    NARCIS (Netherlands)

    Meisner, J.A.; Jaffe, W.J.; Le Poole, R.S.; Pereira, S.F.; Quirrenbach, A.; Raban, D.; Vosteen, A.

    2010-01-01

    The Polarization-Based Collimated Beam Combiner efficiently produces pairwise interference between beams from multiple telescopes. An important feature is achieving ”Photometric Symmetry” whereby interference measurements have no first-order sensitivity to wavefront perturbations (or photometric var

  16. The polarization-based collimated beam combiner and the proposed NOVA fringe tracker (NFT) for the VLTI

    NARCIS (Netherlands)

    Meisner, J.A.; Jaffe, W.J.; Poole, R.S. le; Pereira, S.F.; Quirrenbach, A.; Raban, D.; Vosteen, L.L.A.

    2010-01-01

    The Polarization-Based Collimated Beam Combiner efficiently produces pairwise interference between beams from multiple telescopes. An important feature is achieving "Photometric Symmetry" whereby interference measurements have no first-order sensitivity to wavefront perturbations (or photometric var

  17. The technique of high power laser beam combination using liquid crystal spatial light modulator

    Science.gov (United States)

    Duan, Ying-ying; Wang, Xiang-ru; Huang, Zi-qiang

    2013-09-01

    Based on the phase modulation characteristics of optically addressed liquid crystal spatial light modulator (OA-LC-SLM) which is realized by controlling the power of addressing light, a physical model of coherent beam combination fiber laser using a bunch of fibers and a device of OA-LC-SLM is established on the theory of diffraction optics and liquid crystal birefringence effect. On the basis of this model, the properties of given scheme of coherent beam combination fiber laser are investigated including main lobe distribution and ability of phase modulation. Meanwhile, the plot functions of phase modulation versus the optical power of addressing light are obtained on different given driving voltage conditions and fiber alignment parameters such as core diameter and filling factor. After the numerical simulation, it shows that, this coherent beam combination fiber laser using OA-LC-SLM demonstrates an ability of coherent beam combination on the far field. With the increase of core diameter, the combination efficiency is improved better, and the divergence angle decreases narrower.

  18. Stable deep nulling in polychromatic unpolarized light with multiaxial beam combination.

    Science.gov (United States)

    Buisset, Christophe; Rejeaunier, Xavier; Rabbia, Yves; Barillot, Marc

    2007-11-10

    In the context of the space-based nulling mission ESA-Darwin, Thales Alenia Space has developed a nulling breadboard for the European Space Agency (ESA): the multiaperture imaging interferometer (MAII) to demonstrate deep and stable nulling and to investigate various subsystems of the ESA-Darwin interferometer. Recently, we have extended our investigations to the multiaxial beam combination. This combination scheme presents many advantages: simplicity, compactness, and a high coupling efficiency for a three-beam combination. The near-infrared (lambda approximately 1.55 microm) MAII breadboard has been upgraded to the multiaxial beam combination. Polarization and stability issues have been thoroughly investigated. We report on the recent results we have obtained with the multiaxial configuration of MAII in unpolarized light with a relative spectral bandwidth of 5%: nulling ratios of mean value N=1.7 x 10(-5), stable over 1 h with a standard deviation sigma( N )=5.7 x 10(-7). These results indicate that the multiaxial beam combination has the potential to meet Darwin requirements. PMID:17994130

  19. Coherent beam combination technique using SBS-PCM for high repetition rate lasers

    International Nuclear Information System (INIS)

    A plasma generation by laser-matter interaction is a powerful tool in the field of plasma research and applications. Recently, laser-induced plasma has been given a great attention, from material science to plasma deposition. However, current laser technologies have difficulty on increasing the laser power because of the thermal problems of the laser medium. The beam combination laser can overcome the thermal problems as it coherently combines multiple existing lasers without additional need for thermal management. H. J. Kong et al. developed the beam combination laser using the phase controlled stimulated Brillouin scattering phase conjugate mirrors (SBS-PCMs) has been developed. The key factor for achievement of the coherent combination is to overcome the randomness of the SBS phase. To lock/control the phases of the SBS waves, H. J. Kong et al. proposed and have developed a new phase control technique, so called “the self phase control technique.” The phase of each sub-beam can be controlled independently with the simplest arrangement. Thus, energy scaling is easily achieved by just increasing the number of the combined beams. The effective of this technique has been demonstrated experimentally over a decade. In this work, the phase control of a tiled four-beam combination laser is successfully performed with amplification. The relative phase fluctuations are measured from the interference pattern that is generated from the combined output beam and the reference beam. Without amplification, the combined output energy is 9.9 ± 0.5 mJ when the input energy is 32.2 ± 0.3 mJ. In this case, the standard deviations of the phase differences are measured to be λ/116, λ/38.9, λ/31.5, and λ/39.5, during 2,500 shots (250 s). When the amplifiers are operating, the combined output energy is 169 ± 6 mJ corresponding to the total gain of 5.3. In this case, the standard deviations of the phase differences are measured to be λ/68.8, λ/26.5, λ/28.0, and λ/26

  20. Strengthening of RC Beams Using Externally Bonded Reinforcement Combined with Near-Surface Mounted Technique

    Directory of Open Access Journals (Sweden)

    Kh Mahfuz ud Darain

    2016-07-01

    Full Text Available This study investigates the flexural behaviour of reinforced concrete (RC beams strengthened through the combined externally bonded and near-surface mounted (CEBNSM technique. The externally bonded reinforcement (EBR and near-surface mounted (NSM techniques are popular strengthening solutions, although these methods often demonstrate premature debonding failure. The proposed CEBNSM technique increases the bond area of the concrete–carbon fibre reinforced polymer (CFRP interface, which can delay the debonding failure. This technique is appropriate when any structure has a narrow cross-sectional width or is in need of additional flexural capacity that an individual technique or material cannot attain. An experimental test matrix was designed with one control and five strengthened RC beams to verify the performance of the proposed technique. The strengthening materials were CFRP bar as NSM reinforcement combined with CFRP fabric as EBR material. The test variables were the diameter of the NSM bars (8 and 10 mm, the thickness of the CFRP fabrics (one and two layers and the U-wrap anchorage. The strengthened beams showed enhancement of ultimate load capacity, stiffness, cracking behaviour, and strain compatibility. The ultimate capacity of the CEBNSM-strengthened beams increased from 71% to 105% compared to that of the control beam. A simulation method based on the moment-rotation approach was also presented to predict the behaviour of CEBNSM-strengthened RC beams.

  1. 16 W output power by high-efficient spectral beam combining of DBR-tapered diode lasers

    DEFF Research Database (Denmark)

    Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin;

    2011-01-01

    output power achieved by spectral beam combining of two single element tapered diode lasers. Since spectral beam combining does not affect beam propagation parameters, M2-values of 1.8 (fast axis) and 3.3 (slow axis) match the M2- values of the laser with lowest spatial coherence. The principle of......Up to 16 W output power has been obtained using spectral beam combining of two 1063 nm DBR-tapered diode lasers. Using a reflecting volume Bragg grating, a combining efficiency as high as 93.7% is achieved, resulting in a single beam with high spatial coherence. The result represents the highest...... spectral beam combining used in our experiments can be expanded to combine more than two tapered diode lasers and hence it is expected that the output power may be increased even further in the future....

  2. NUMERICAL PREDICTION OF COMPOSITE BEAM SUBJECTED TO COMBINED NEGATIVE BENDING AND AXIAL TENSION

    Directory of Open Access Journals (Sweden)

    MAHESAN BAVAN

    2013-08-01

    Full Text Available The present study has investigated the finite element method (FEM techniques of composite beam subjected to combined axial tension and negative bending. The negative bending regions of composite beams are influenced by worsen failures due to various levels of axial tensile loads on steel section especially in the regions near internal supports. Three dimensional solid FEM model was developed to accurately predict the unfavourable phenomenon of cracking of concrete and compression of steel in the negative bending regions of composite beam due to axial tensile loads. The prediction of quasi-static solution was extensively analysed with various deformation speeds and energy stabilities. The FEM model was then validated with existing experimental data. Reasonable agreements were observed between the results of FEM model and experimental analysis in the combination of vertical-axial forces and failure modes on ultimate limit state behaviour. The local failure modes known as shear studs failure, excess yielding on steel beam and crushing on concrete were completely verified by extensive similarity between the numerical and experimental results. Finally, a proper way of modelling techniques for large FEM models by considering uncertainties of material behaviour due to biaxial loadings and complex contact interactions is discussed. Further, the model is suggested for the limit state prediction of composite beam with calibrating necessary degree of the combined axial loads.

  3. Patterning of titanium oxide nanostructures by electron-beam lithography combined with plasma etching

    International Nuclear Information System (INIS)

    Patterning of metal oxide nanostructures with precisely controlled geometries and spacings can play an important role in the improvement of sensors for gas detection. Titanium oxide thin films were deposited on oxidized silicon substrates by reactive magnetron sputtering at room temperature. Patterning of TiO2 nanostructures was conducted by electron beam lithography combined with plasma etching. It was found that for 120 nm-thick TiO2 nanostructure formation, HSQ e-beam resists and Cr films prove to be suitable mask materials. Experimental results showed that the size of TiO2 nanostructures depends mainly on the e-beam lithography process and they can be controlled by the design geometry and the exposure dose. TiO2 nanostructures with a minimal diameter of 70 nm and spacing of 200 nm were successfully fabricated by ICP etching in CF4/Ar plasma through negative e-beam resist HSQ. (paper)

  4. Combined electron-beam and biological treatment of dyeing complex wastewater. Pilot plant experiments

    International Nuclear Information System (INIS)

    Pilot plant (output 1000 m3 day-1) with ELV electron accelerator (energy 1 MeV, beam power 40 kW) is in operation from October 1998. Combined electron-beam and biological treatment was used for purification of dyeing complex wastewater under continuous flow conditions. The main results of pilot-scale experiments consisted in the fact that decrease in total content of pollutants after biological treatment was substantially influenced by preliminary electron-beam treatment (mainly, because of radiolytic conversions of terephthalic acid being a main pollutant of the wastewater). Equal purification degree corresponded to 17 h of bio-treatment without preliminary irradiation and about 8 h of bio-treatment with preliminary electron-beam treatment at absorbed dose 1-2 kGy

  5. Patterning of titanium oxide nanostructures by electron-beam lithography combined with plasma etching

    Science.gov (United States)

    Hotovy, I.; Kostic, I.; Nemec, P.; Predanocy, M.; Rehacek, V.

    2015-07-01

    Patterning of metal oxide nanostructures with precisely controlled geometries and spacings can play an important role in the improvement of sensors for gas detection. Titanium oxide thin films were deposited on oxidized silicon substrates by reactive magnetron sputtering at room temperature. Patterning of TiO2 nanostructures was conducted by electron beam lithography combined with plasma etching. It was found that for 120 nm-thick TiO2 nanostructure formation, HSQ e-beam resists and Cr films prove to be suitable mask materials. Experimental results showed that the size of TiO2 nanostructures depends mainly on the e-beam lithography process and they can be controlled by the design geometry and the exposure dose. TiO2 nanostructures with a minimal diameter of 70 nm and spacing of 200 nm were successfully fabricated by ICP etching in CF4/Ar plasma through negative e-beam resist HSQ.

  6. An Integrated Optics beam combiner for the second generation VLTI instruments

    CERN Document Server

    Benisty, M; Jocou, L; Labeye, P; Malbet, F; Perraut, K; Kern, P

    2009-01-01

    The very recent years have seen a promising start in scientific publications making use of images produced by near-infrared long-baseline interferometry. The technique has reached, at last, a technical maturity level that opens new avenues for numerous astrophysical topics requiring milli-arcsecond model-independent imaging. The Very Large Telescope Interferometer (VLTI) is on the path to be equipped with instruments capable to combine between four to six telescopes. In the framework of the VLTI second generation instruments Gravity and VSI, we propose a new beam combining concept using Integrated Optics (IO) technologies with a novel ABCD-like fringe encoding scheme. Our goal is to demonstrate that IO-based combination brings considerable advantages in terms of instrumental design and performance. We therefore aim at giving a full characterization of an IO beam combiner to establish its performances and check its compliance with the specifications of an imaging instrument. Laboratory measurements were made i...

  7. Astronomical Video Suites

    Science.gov (United States)

    Francisco Salgado, Jose

    2010-01-01

    Astronomer and visual artist Jose Francisco Salgado has directed two astronomical video suites to accompany live performances of classical music works. The suites feature awe-inspiring images, historical illustrations, and visualizations produced by NASA, ESA, and the Adler Planetarium. By the end of 2009, his video suites Gustav Holst's The Planets and Astronomical Pictures at an Exhibition will have been presented more than 40 times in over 10 countries. Lately Salgado, an avid photographer, has been experimenting with high dynamic range imaging, time-lapse, infrared, and fisheye photography, as well as with stereoscopic photography and video to enhance his multimedia works.

  8. Channel Spectral Separation Narrowing for Spectral Beam Combining by Apodisation of the Reflecting Volume Bragg Grating

    OpenAIRE

    Shen Benjian; Tan Jichun; Guangwei Zheng; Yanlan He

    2011-01-01

    The sidelobe in diffraction efficiency of reflecting volume Bragg grating (RVBG) limits the wavelength channel spectral separation, which determines the combining power output in spectral beam combining (SBC) systems. A novel SBC system based on the apodised RVBG has been proposed to suppress the sidelobe. Several apodised RVBGs have been compared and the optimal apodised RVBG is obtained by using the chain-matrix approach. Numerical results show that the sidelobe could be suppressed excellen...

  9. Spatial Phase and Amplitude Structuring of Beams Using a Combination of Multiple Orthogonal Spatial Functions with Complex Coefficients

    CERN Document Server

    Xie, Guodong; Li, Long; Ren, Yongxiong; Zhao, Zhe; Yan, Yan; Ahmed, Nisar; Wang, Zhe; Willner, Asher J; Bao, Changjing; Cao, Yinwen; Ziyadi, Morteza; Almaiman, Ahmed; Ashrafi, Solyman; Tur, Moshe; Willner, Alan E

    2016-01-01

    Analogous to time signals that can be composed of multiple frequency functions, we use uniquely structured orthogonal spatial modes to create different beam shapes. We tailor the spatial structure by judiciously choosing a weighted combination of multiple modal states within an orthogonal basis set, and we can tunably create beam phase and intensity "shapes" that are not otherwise readily achievable. As an example shape, we use a series of orbital-angular-momentum (OAM) functions with adjustable complex weights to create a reconfigurable spatial region of higher localized power as compared to traditional beam combining. We simulate a structured beam created by coherently combining several orthogonal OAM beams with different complex weights, and we achieve a >10X localized power density enhancement with 19 beams. Additionally, we can create unique shapes by passing a single beam through a specially designed phase and intensity mask that contains the combination of multiple OAM functions each with complex weigh...

  10. Treatment of liquid separated from sludge by the method using electron beam and ozone in combination

    International Nuclear Information System (INIS)

    Since the liquid separated from sludge in the dehydration or concentration process of sewer sludge contains considerable amount of organic compositions that are hard to be decomposed by microorganisms, it has become difficult to be treated by conventional activated sludge process. In the case of discharging the separated liquid into closed water areas, the higher quality treatment is required. The method of using electron beam irradiation and ozone oxidation in combination for cleaning the liquid separated from sludge was examined, therefore, the results are reported. The water quality of the sample from the sludge treatment plant in A City is shown. The method of bio-pretreatment, the treatment method by using electron beam and ozone in combination, and the method of analyzing the water quality are described. The effect of the treatment by activated sludge process, as the effect of the treatment by the combined use of electron beam and ozone, the change of COD and TOC, the change of chromaticity, the change of gel chromatogram, and the reaction mechanism are reported. In this paper, only the basic concept on the model plant for applying the method of the combined use of electron beam and ozone to the treatment of the liquid separated from sludge is discussed. (K.I.)

  11. Direct UV-Written Integrated Optical Beam Combiner for Stellar Interferometry

    DEFF Research Database (Denmark)

    Olivero, Massimo; Svalgaard, Mikael; Jocou, L.;

    2007-01-01

    In this paper, we report the fabrication of an optical-beam combiner for stellar interferometry by means of direct ultraviolet (UV) writing. The component is shown to have good performance (fringe contrast > 95%, total loss similar to 0.7, -40-dB crosstalk, broadband operation covering at least the...

  12. Spatial Combining of Laser-Diode Beams for Pumping an NPRO

    Science.gov (United States)

    Gelsinger, Paul; Liu, Duncan; Mulder, Jerry; Aguayo, Francisco

    2008-01-01

    A free-space optical beam combiner now undergoing development makes it possible to use the outputs of multiple multimode laser diodes to pump a neodymium-doped yttrium aluminum garnet (Nd:YAG) non-planar ring oscillator (NPRO) laser while ensuring that the laser operates at only a single desired frequency. Heretofore, a Nd:YAG NPRO like the present one has been pumped by a single multimode laser-diode beam delivered via an optical fiber. It would be desirable to use multiple pump laser diodes to increase reliability beyond that obtainable from a single pump laser diode. However, as explained in this article, simplistically coupling multiple multimode laser-diode beams through a fiber-optic combiner would entail a significant reduction in coupling efficiency, and lasing would occur at one or more other frequencies in addition to the single desired frequency. To minimize coupling loss, one must ensure that the NA (approximately equal to 0.3) of the combined laser-diode beams is less than the NA of the fiber. The A(Omega) of the laser-diode beam in the slow-axis plane is 1/1.3 as large as that of the fiber. This A(Omega) is small enough to enable efficient coupling of light into the optical fiber, but too large for combining of beams in the slow-axis plane. Therefore, a pair of cylindrical lenses is used to cancel the slow-axis plane magnification introduced by the on-cylindrical lenses used to effect magnification in the fast-axis plane.

  13. Finite element modeling of reinforced concrete beams with a hybrid combination of steel and aramid reinforcement

    International Nuclear Information System (INIS)

    Highlights: • Modeling of concrete beams reinforced steel and FRP bars. • Developed finite element models achieved good results. • The models are validated via comparison with experimental results. • Parametric studies are performed. - Abstract: Corrosion of steel bars has an adverse effect on the life-span of reinforced concrete (RC) members and is usually associated with crack development in RC beams. Fiber reinforced polymer (FRP) bars have been recently used to reinforce concrete members in flexure due to their high tensile strength and superior corrosion resistance properties. However, FRP materials are brittle in nature, thus RC beams reinforced with such materials would exhibit a less ductile behavior when compared to similar members reinforced with conventional steel reinforcement. Recently, researchers investigated the performance of concrete beams reinforced with a hybrid combination of steel and Aramid Fiber Reinforced Polymer (AFRP) reinforcement to maintain a reasonable level of ductility in such members. The function of the AFRP bars is to increase the load-carrying capacity, while the function of the steel bars is to ensure ductility of the flexural member upon yielding in tension. This paper presents a three-dimensional (3D) finite element (FE) model that predicted the load versus mid-span deflection response of tested RC beams conducted by other researchers with a hybrid combination of steel and AFRP bars. The developed FE models account for the constituent material nonlinearities and bond–slip behavior between the reinforcing bars and adjacent concrete surfaces. It was concluded that the developed models can accurately capture the behavior and predicts the load-carrying capacity of such RC members. In addition, a parametric study is conducted using the validated models to investigate the effect of AFRP bar size, FRP material type, bond–slip action, and concrete compressive strength on the performance of concrete beams when reinforced

  14. Beam Test of a Prototype Detector Array for the PoGO Astronomical Hard X-Ray/Soft Gamma-Ray Polarimeter

    CERN Document Server

    Mizuno, T; Ng, J S T; Tajima, H; Mitchell, J W; Streitmatter, R E; Fernholz, R C; Groth, E; Fukazawa, Y

    2005-01-01

    Polarization measurements in the X-ray and gamma-ray energy range can provide crucial information on massive compact objects such as black holes and neutron stars. The Polarized Gamma-ray Observer (PoGO) is a new balloon-borne instrument designed to measure polarization from astrophysical objects in the 30-100 keV range, under development by an international collaboration with members from United States, Japan, Sweden and France. To examine PoGO's capability, a beam test of a simplified prototype detector array was conducted at the Argonne National Laboratory Advanced Photon Source. The detector array consisted of seven plastic scintillators, and was irradiated by polarized photon beams at 60, 73, and 83 keV. The data showed a clear polarization signal, with a measured modulation factor of $0.42 \\pm 0.01$. This was successfully reproduced at the 10% level by the computer simulation package Geant4 after modifications to its implementation of polarized Compton/Rayleigh scattering. Details of the beam test and t...

  15. Application of electron-beam irradiation combined with antioxidants for fermented sausage and its quality characteristic

    Science.gov (United States)

    Lim, D. G.; Seol, K. H.; Jeon, H. J.; Jo, C.; Lee, M.

    2008-06-01

    The effects of various doses of electron-beam irradiation on the changes in microbiological attributes of fermented sausage and the combined effect of electron-beam irradiation and various antioxidants on the oxidative stability and sensory properties during cold storage were investigated. Results indicated that 2 kGy of irradiation was the most effective in manufacturing a fermented sausage, and the addition of rosemary extracts was effective in controlling the production of off-flavor and development of lipid oxidation during cold storage.

  16. Application of electron-beam irradiation combined with antioxidants for fermented sausage and its quality characteristic

    Energy Technology Data Exchange (ETDEWEB)

    Lim, D.G.; Seol, K.H.; Jeon, H.J. [Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, San 56-1, Sillim-dong Gwanak-gu, Seoul 151-921 (Korea, Republic of); Jo, C. [Department of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lee, M. [Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, San 56-1, Sillim-dong Gwanak-gu, Seoul 151-921 (Korea, Republic of)], E-mail: moohalee@snu.ac.kr

    2008-06-15

    The effects of various doses of electron-beam irradiation on the changes in microbiological attributes of fermented sausage and the combined effect of electron-beam irradiation and various antioxidants on the oxidative stability and sensory properties during cold storage were investigated. Results indicated that 2 kGy of irradiation was the most effective in manufacturing a fermented sausage, and the addition of rosemary extracts was effective in controlling the production of off-flavor and development of lipid oxidation during cold storage.

  17. Application of electron-beam irradiation combined with antioxidants for fermented sausage and its quality characteristic

    International Nuclear Information System (INIS)

    The effects of various doses of electron-beam irradiation on the changes in microbiological attributes of fermented sausage and the combined effect of electron-beam irradiation and various antioxidants on the oxidative stability and sensory properties during cold storage were investigated. Results indicated that 2 kGy of irradiation was the most effective in manufacturing a fermented sausage, and the addition of rosemary extracts was effective in controlling the production of off-flavor and development of lipid oxidation during cold storage

  18. Electron-beam envelopes and matching for a combined wiggler and alternating-gradient quadrupole channel

    International Nuclear Information System (INIS)

    This work studies the electron-beam envelopes and matching for a combined wiggler and alternating-gradient quadrupole field for a free-electron laser (FEL) that will be operated in the VUV or XUV wavelength region. The quadrupole field is assumed to vary continuously along the symmetry axis. The linearized equations of electron motion are solved analytically by using the two-scale perturbation method for a plane polarized wiggler. The electron-beam envelopes and the envelope equations, as well as the matching conditions in phase space, are obtained from the electron trajectories. A comparison with the numerical solution is presented

  19. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    International Nuclear Information System (INIS)

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20GeV and 180GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by between 11% and 25% compared to the resolution at the electromagnetic scale.

  20. A Layer Correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    CERN Document Server

    Abat, E; Addy, T N; Adragna, P; Aharrouche, M; Ahmad, A; Akesson, T P A; Aleksa, M; Alexa, C; Anderson, K; Andreazza, A; Anghinolfi, F; Antonaki, A; Arabidze, G; Arik, E; Atkinson, T; Baines, J; Baker, O K; Banfi, D; Baron, S; Barr, A J; Beccherle, R; Beck, H P; Belhorma, B; Bell, P J; Benchekroun, D; Benjamin, D P; Benslama, K; Bergeaas Kuutmann, E; Bernabeu, J; Bertelsen, H; Binet, S; Biscarat, C; Boldea, V; Bondarenko, V G; Boonekamp, M; Bosman, M; Bourdarios, C; Broklova, Z; Burckhart Chromek, D; Bychkov, V; Callahan, J; Calvet, D; Canneri, M; Capeans Garrido, M; Caprini, M; Cardiel Sas, L; Carli, T; Carminati, L; Carvalho, J; Cascella, M; Castillo, M V; Catinaccio, A; Cauz, D; Cavalli, D; Cavalli Sforza, M; Cavasinni, V; Cetin, S A; Chen, H; Cherkaoui, R; Chevalier, L; Chevallier, F; Chouridou, S; Ciobotaru, M; Citterio, M; Clark, A; Cleland, B; Cobal, M; Cogneras, E; Conde Muino, P; Consonni, M; Constantinescu, S; Cornelissen, T; Correard, S; Corso Radu, A; Costa, G; Costa, M J; Costanzo, D; Cuneo, S; Cwetanski, P; Da Silva, D; Dam, M; Dameri, M; Danielsson, H O; Dannheim, D; Darbo, G; Davidek, T; De, K; Defay, P O; Dekhissi, B; Del Peso, J; Del Prete, T; Delmastro, M; Derue, F; Di Ciaccio, L; Di Girolamo, B; Dita, S; Dittus, F; Djama, F; Djobava, T; Dobos, D; Dobson, M; Dolgoshein, B A; Dotti, A; Drake, G; Drasal, Z; Dressnandt, N; Driouchi, C; Drohan, J; Ebenstein, W L; Eerola, P; Efthymiopoulos, I; Egorov, K; Eifert, T F; Einsweiler, K; El Kacimi, M; Elsing, M; Emelyanov, D; Escobar, C; Etienvre, A I; Fabich, A; Facius, K; Fakhr-Edine, A I; Fanti, M; Farbin, A; Farthouat, P; Fassouliotis, D; Fayard, L; Febbraro, R; Fedin, O L; Fenyuk, A; Fergusson, D; Ferrari, P; Ferrari, R; Ferreira, B C; Ferrer, A; Ferrere, D; Filippini, G; Flick, T; Fournier, D; Francavilla, P; Francis, D; Froeschl, R; Froidevaux, D; Fullana, E; Gadomski, S; Gagliardi, G; Gagnon, P; Gallas, M; Gallop, B J; Gameiro, S; Gan, K K; Garcia, R; Garcia, C; Gavrilenko, I L; Gemme, C; Gerlach, P; Ghodbane, N; Giakoumopoulou, V; Giangiobbe, V; Giokaris, N; Glonti, G; Göttfert, T.; Golling, T; Gollub, N; Gomes, A; Gomez, M D; Gonzalez-Sevilla, S; Goodrick, M J; Gorfine, G; Gorini, B; Goujdami, D; Grahn, K J; Grenier, P; Grigalashvili, N; Grishkevich, Y; Grosse-Knetter, J; Gruwe, M; Guicheney, C; Gupta, A; Haeberli, C; Härtel, R.; Hajduk, Z; Hakobyan, H; Hance, M; Hansen, J D; Hansen, P H; Hara, K; Harvey, A., Jr; Hawkings, R J; Heinemann, F E W; Henriques Correia, A; Henss, T; Hervas, L; Higon, E; Hill, J C; Hoffman, J; Hostachy, J Y; Hruska, I; Hubaut, F; Huegging, F; Hulsbergen, W; Hurwitz, M; Iconomidou-Fayard, L; Jansen, E; Jen-La Plante, I; Johansson, P D C; Jon-And, K; Joos, M; Jorgensen, S; Joseph, J; Kaczmarska, A; Kado, M; Karyukhin, A; Kataoka, M; Kayumov, F; Kazarov, A; Keener, P T; Kekelidze, G D; Kerschen, N; Kersten, S; Khomich, A; Khoriauli, G; Khramov, E; Khristachev, A; Khubua, J; Kittelmann, T H; Klingenberg, R; Klinkby, E B; Kodys, P; Koffas, T; Kolos, S; Konovalov, S P; Konstantinidis, N; Kopikov, S; Korolkov, I; Kostyukhin, V; Kovalenko, S; Kowalski, T Z; Krüger, K.; Kramarenko, V; Kudin, L G; Kulchitsky, Y; Lacasta, C; Lafaye, R; Laforge, B; Lampl, W; Lanni, F; Laplace, S; Lari, T; Le Bihan, A C; Lechowski, M; Ledroit-Guillon, F; Lehmann, G; Leitner, R; Lelas, D; Lester, C G; Liang, Z; Lichard, P; Liebig, W; Lipniacka, A; Lokajicek, M; Louchard, L; Lourerio, K F; Lucotte, A; Luehring, F; Lund-Jensen, B; Lundberg, B; Ma, H; Mackeprang, R; Maio, A; Maleev, V P; Malek, F; Mandelli, L; Maneira, J; Mangin-Brinet, M; Manousakis, A; Mapelli, L; Marques, C; Marti i Garcia, S; Martin, F; Mathes, M; Mazzanti, M; McFarlane, K W; McPherson, R; Mchedlidze, G; Mehlhase, S; Meirosu, C; Meng, Z; Meroni, C; Mialkovski, V; Mikulec, B; Milstead, D; Minashvili, I; Mindur, B; Mitsou, V A; Moed, S; Monnier, E; Moorhead, G; Morettini, P; Morozov, S V; Mosidze, M; Mouraviev, S V; Moyse, E W J; Munar, A; Myagkov, A; Nadtochi, A V; Nakamura, K; Nechaeva, P; Negri, A; Nemecek, S; Nessi, M; Nesterov, S Y; Newcomer, F M; Nikitine, I; Nikolaev, K; Nikolic-Audit, I; Ogren, H; Oh, S H; Oleshko, S B; Olszowska, J; Onofre, A; Padilla Aranda, C; Paganis, S; Pallin, D; Pantea, D; Paolone, V; Parodi, F; Parsons, J; Parzhitskiy, S; Pasqualucci, E; Passmored, S M; Pater, J; Patrichev, S; Peez, M; Perez Reale, V; Perini, L; Peshekhonov, V D; Petersen, J; Petersen, T C; Petti, R; Phillips, P W; Pina, J; Pinto, B; Podlyski, F; Poggioli, L; Poppleton, A; Poveda, J; Pralavorio, P; Pribyl, L; Price, M J; Prieur, D; Puigdengoles, C; Puzo, P; Røhne, O.; Ragusa, F; Rajagopalan, S; Reeves, K; Reisinger, I; Rembser, C; Bruckman de Renstrom, P A; Reznicek, P; Ridel, M; Risso, P; Riu, I; Robinson, D; Roda, C; Roe, S; Rohne, O; Romaniouk, A; Rousseau, D; Rozanov, A; Ruiz, A; Rusakovich, N; Rust, D; Ryabov, Y F; Ryjov, V; Salto, O; Salvachua, B; Salzburger, A; Sandaker, H; Santamarina Rios, C; Santi, L; Santoni, C; Saraiva, J G; Sarri, F; Sauvage, G; Says, L P; Schaefer, M; Schegelsky, V A; Schiavi, C; Schieck, J; Schlager, G; Schlereth, J; Schmitt, C; Schultes, J; Schwemling, P; Schwindling, J; Seixas, J M; Seliverstov, D M; Serin, L; Sfyrla, A; Shalanda, N; Shaw, C; Shin, T; Shmeleva, A; Silva, J; Simion, S; Simonyan, M; Sloper, J E; Smirnov, S.Yu; Smirnova, L; Solans, C; Solodkov, A; Solovianov, O; Soloviev, I; Sosnovtsev, V V; Spano, F; Speckmayer, P; Stancu, S; Stanek, R; Starchenko, E; Straessner, A; Suchkov, S I; Suk, M; Szczygiel, R; Tarrade, F; Tartarelli, F; Tas, P; Tayalati, Y; Tegenfeldt, F; Teuscher, R; Thioye, M; Tikhomirov, V O; Timmermans, C J W P; Tisserant, S; Toczek, B; Tremblet, L; Troncon, C; Tsiareshka, P; Tyndel, M; Karagoez Unel, M; Unal, G; Unel, G; Usai, G; Van Berg, R; Valero, A; Valkar, S; Valls, J A; Vandelli, W; Vannucci, F; Vartapetian, A; Vassilakopoulos, V I; Vasilyeva, L; Vazeille, F; Vernocchi, F; Vetter-Cole, Y; Vichou, I; Vinogradov, V; Virzi, J; Vivarelli, I; de Vivie, J B; Volpi, M; Vu Anh, T; Wang, C; Warren, M; Weber, J; Weber, M; Weidberg, A R; Weingarten, J; Wells, P S; Werner, P; Wheeler, S; Wiessmann, M; Wilkens, H; Williams, H H; Wingerter-Seez, I; Yasu, Y; Zaitsev, A; Zenin, A; Zenis, T; Zenonos, Z; Zhang, H; Zhelezko, A; Zhou, N

    2011-01-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of the calorimeter layer energy deposits, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Geant4 Monte Carlo events and used to reconstruct the energy of pions impinging on the calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. For pion beams with energies between 20 and 180 GeV, the particle energy is reconstructed within 3% and the energy resolution is improved by 11% to 25% compared to the response at the electromagnetic scale.

  1. Observatory Sponsoring Astronomical Image Contest

    Science.gov (United States)

    2005-05-01

    and to provide a showcase for a broad range of astronomical research and celestial objects," Adams added. In addition, NRAO is developing enhanced data visualization techniques and data-processing recipes to assist radio astronomers in making quality images and in combining radio data with data collected at other wavelengths, such as visible-light or infrared, to make composite images. "We encourage all our telescope users to take advantage of these techniques to showcase their research," said Juan Uson, a member of the NRAO scientific staff and the observatory's EPO scientist. "All these efforts should demonstrate the vital and exciting roles that radio telescopes, radio observers, and the NRAO play in modern astronomy," Lo said. "While we want to encourage images that capture the imagination, we also want to emphasize that extra effort invested in enhanced imagery also will certainly pay off scientifically, by revealing subtleties and details that may have great significance for our understanding of astronomical objects," he added. Details of the NRAO Image Contest, which will become an annual event, are on the observatory's Web site. The observatory will announce winners on October 15. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

  2. Comparison of coherent and incoherent laser beam combination for tactical engagements

    Science.gov (United States)

    Van Zandt, Noah R.; Cusumano, Salvatore J.; Bartell, Richard J.; Basu, Santasri; McCrae, Jack E.; Fiorino, Steven T.

    2012-10-01

    The performance of a multibeam laser system is evaluated for coherent and incoherent beam combination under tactical scenarios. For direct comparison, identical aperture geometries are used for both, coherent or incoherent, combination methods. The analysis assumes a multilaser source coupled with a conventional 0.32 m diameter, on-axis, beam director. Parametric analysis includes variations over residual errors, beam quality, atmospheric effects, and scenario geometry. Analytical solutions from previous results are used to evaluate performance for the vacuum case, providing an upper bound on performance and a backdrop for organizing the multitude of effects as they are analyzed. Wave optics simulations are used for total system performance. Each laser in the array has a wavelength of 1.07 μm, 10 kW (25 kW) output power, and Gaussian exitance profile. Both tracking and full-aperture adaptive optics are modeled. Three tactical engagement geometries, air to surface, surface to air, and surface to surface, are evaluated for slant ranges from 2.5 to 10 km. Two near-median atmospheric profiles were selected based upon worldwide climatological data. The performance metric used is beam propagation efficiency for circular target diameters of 5 and 10 cm.

  3. Brassboard Astrometric Beam Combiner (ABC) Development for the Space Interferometry Mission (SIM)

    Science.gov (United States)

    Jeganathan, Muthu; Kuan, Gary; Rud, Mike; Lin, Sean; Sutherland, Kristen; Moore, James; An, Xin

    2008-01-01

    The Astrometric Beam Combiner (ABC) is a critical element of the Space Interferometry Mission (SIM) that performs three key functions: coherently combine starlight from two siderostats; individually detect starlight for angle tracking; and disperse and detect the interferometric fringes. In addition, the ABC contains: a stimulus, cornercubes and shutters for in-orbit calibration; several tip/tilt mirror mechanisms for in-orbit alignment; and internal metrology beam launcher for pathlength monitoring. The detailed design of the brassboard ABC (which has the form, fit and function of the flight unit) is complete, procurement of long-lead items is underway, and assembly and testing is expected to be completed in Spring 2009. In this paper, we present the key requirements for the ABC, details of the completed optical and mechanical design as well as plans for assembly and alignment.

  4. Array size scaling of passive coherent beam combination in fiber laser array

    Institute of Scientific and Technical Information of China (English)

    Yuhao Xue; Bing He; Jun Zhou; Jinchong Xue; Zhen Li; Houkang Liu; Qihong Lou

    2012-01-01

    Array size scaling of passive coherent beam combination is explored theoretically.The Strehl ratio variation with wavelength is simulated in 4-,9-,16-,and 25-channel fiber arrays.The average Strehl ratio and phase error are calculated.The Strehl ratio is found to be near 100% for arrays with less than 5 fibers,but decreases significantly for larger arrays.These results are in good agreement with the recent experimental results.

  5. Combined Compression and Shear Structural Evaluation of Stiffened Panels Fabricated Using Electron Beam Freeform Fabrication

    OpenAIRE

    Nelson, Erik Walter

    2008-01-01

    Unitized aircraft structures have the potential to be more efficient than current aircraft structures. The Electron Beam Freeform Fabrication (EBF3) process can be used to manufacture unitized aircraft structures. The structural efficiency of blade stiffened panels made with EBF3 was compared to panels made by integrally machining from thick plate. The panels were tested under two load cases in a combined compression-shear load test fixture. One load case tested the panels' responses to a...

  6. Combining tissue-phantom ratios to provide a beam-quality specifier for flattening filter free photon beams.

    OpenAIRE

    Dalaryd, Mårten; Knöös, Tommy; Ceberg, Crister

    2014-01-01

    There are currently several commercially available radiotherapy treatment units without a flattening filter in the beam line. Unflattened photon beams have an energy and lateral fluence distribution that is different from conventional beams and, thus, their attenuation properties differ. As a consequence, for flattening filter free (FFF) beams, the relationship between the beam-quality specifier TPR20,10 and the Spencer-Attix restricted water-to-air mass collision stopping-power ratios, L̄/ρa...

  7. Astrobiology: An Astronomer's Perspective

    OpenAIRE

    Bergin, Edwin A.

    2013-01-01

    In this review we explore aspects of the field of astrobiology from an astronomical viewpoint. We therefore focus on the origin of life in the context of planetary formation, with additional emphasis on tracing the most abundant volatile elements, C, H, O, and N that are used by life on Earth. We first explore the history of life on our planet and outline the current state of our knowledge regarding the delivery of the C, H, O, N elements to the Earth. We then discuss how astronomers track th...

  8. Zelenchukskaya Radio Astronomical Observatory

    Science.gov (United States)

    Smolentsev, Sergey; Dyakov, Andrei

    2013-01-01

    This report summarizes information about Zelenchukskaya Radio Astronomical Observatory activities in 2012. Last year a number of changes took place in the observatory to improve some technical characteristics and to upgrade some units to the required status. The report provides an overview of current geodetic VLBI activities and gives an outlook for the future.

  9. Svetloe Radio Astronomical Observatory

    Science.gov (United States)

    Smolentsev, Sergey; Rahimov, Ismail

    2013-01-01

    This report summarizes information about the Svetloe Radio Astronomical Observatory activities in 2012. Last year, a number of changes took place in the observatory to improve some technical characteristics and to upgrade some units to their required status. The report provides an overview of current geodetic VLBI activities and gives an outlook for the future.

  10. Poznan acute Astronomical Observatory

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    This Poznan acute Astronomical Observatory is a unit of the Adam Mickiewicz University, located in Poznan acute, Poland. From its foundation in 1919, it has specialized in astrometry and celestial mechanics (reference frames, dynamics of satellites and small solar system bodies). Recently, research activities have also included planetary and stellar astrophysics (asteroid photometry, catalysmic b...

  11. Coherent Tiled 4 Beam Combination by Phase Controlled Stimulated Brillouin Scattering Phase Conjugation Mirrors toward the Practical Laser Fusion Driver

    International Nuclear Information System (INIS)

    Full text: The coherent beam combination using the phase controlled stimulated Brillouin scattering phase conjugate mirrors (SBS-PCMs) is one of the promising techniques for the practical laser fusion drivers. Its ability has been demonstrated experimentally through this work. The phase fluctuations of the titled beams are less than 1/25 wavelength even when the amplifiers are inserted and operated in the beam combining system, which means that this new technique can be applied to combine the currently available lasers such as 100 J/ns/10 Hz for a real laser driver module whose output energy is greater than 5 kJ/ns/10 Hz. (author)

  12. Analysis of the effects of mismatched errors on coherent beam combining based on a self-imaging waveguide

    Science.gov (United States)

    Tao, R.; Wang, X.; Zhou, Pu; Si, Lei

    2016-01-01

    A theoretical model of coherent beam combining (CBC) based on a self-imaging waveguide (SIW) is built and the effects of mismatched errors on SIW-based CBC are simulated and analysed numerically. With the combination of the theoretical model and the finite difference beam propagation method, two main categories of errors, assembly and nonassembly errors, are numerically studied to investigate their effect on the beam quality by using the M2 factor. The optimisation of the SIW and error control principle of the system is briefly discussed. The generalised methodology offers a good reference for investigating waveguide-based high-power coherent combining of fibre lasers in a comprehensive way.

  13. Propagation properties of off-axis Hermite-cosh-Gaussian beam combinations through a first-order optical system

    Institute of Scientific and Technical Information of China (English)

    Tang Qian-Jin; Chen Da-Ming; Yu Yong-Ai; Hu Qi-Quan

    2006-01-01

    Based on the Collins integral formula, the analytic expressions of propagation of the coherent and the incoherent off-axis Hermite-cosh-Gaussian (HChG) beam combinations with rectangular symmetry passing through a paraxial first-order optical system are derived, and corresponding numerical examples are given and analysed. The resulting beam quality is discussed in terms of power in the bucket (PIB). The study suggests that the resulting beam cannot keep the initial intensity shape during the propagation and the beam quality for coherent mode is not always better than that for incoherent mode. Reviewing the numerical simulations of Gaussian, Hermite-Gaussian (HG) and cosh-Gaussian (ChG) beam combinations indicates that the Hermite polynomial exerts a chief influence on the irradiance profile of composite beam and far field power concentration.

  14. Damage evaluation of reinforced concrete frame based on a combined fiber beam model

    Science.gov (United States)

    Shang, Bing; Liu, ZhanLi; Zhuang, Zhuo

    2014-04-01

    In order to analyze and simulate the impact collapse or seismic response of the reinforced concrete (RC) structures, a combined fiber beam model is proposed by dividing the cross section of RC beam into concrete fiber and steel fiber. The stress-strain relationship of concrete fiber is based on a model proposed by concrete codes for concrete structures. The stress-strain behavior of steel fiber is based on a model suggested by others. These constitutive models are implemented into a general finite element program ABAQUS through the user defined subroutines to provide effective computational tools for the inelastic analysis of RC frame structures. The fiber model proposed in this paper is validated by comparing with experiment data of the RC column under cyclical lateral loading. The damage evolution of a three-dimension frame subjected to impact loading is also investigated.

  15. The Improved Power of the Central Lobe in the Beam Combination and High Power Output

    International Nuclear Information System (INIS)

    In order to increase the power fraction of the central lobe in the coherent beam combination of lasers in an array, the effects of the distance factor of near-field distribution on far-field interference patterns are calculated and demonstrated experimentally. An improved beam array of interwoven distribution is demonstrated to enable the power in the central lobe to reach 41%. An optimized mirror array is carefully designed to obtain a high duty ratio, which is up to 53.3% at a high power level. By using these optimized methods and designs, the passive phase locking of eight Yb-doped fiber amplifiers with ring cavities are obtained, and a pleasing interference pattern with 87% visibility is observed. The maximum coherent output power of the system is up to 1066 W. (fundamental areas of phenomenology(including applications))

  16. Durability of Steel Fibres Reinforcement Concrete Beams in Chloride Environment Combined with Inhibitor

    Directory of Open Access Journals (Sweden)

    AbdelMonem Masmoudi

    2016-01-01

    Full Text Available This paper presented the effect of the combination of an inhibitor and steel fibre reinforced concrete (SFRC for concrete structures in chloride environments. Twelve beams were cast and tested to study their flexural behavior. The morphology of steel surfaces using the inhibitor after observing the scanning electron microscope showed a low layer of corrosion products. The steel surface immersed in the inhibitor free solution was seen to have been subject to chloride ions attacks as shown in this study. The interest to the field of the present study is the relatively higher durability of the performance when using the inhibitor. Crack width and crack spacing for beams under the same load showed that the use of SFRC with the inhibitor for concrete structures in chloride environments must have transferred tension across cracks that led to reducing crack spacing without any chloride ions attack.

  17. Electron beam combined with hydrothermal treatment for enhancing the enzymatic convertibility of sugarcane bagasse

    International Nuclear Information System (INIS)

    The use of microbial cellulolytic enzymes is the most efficient process to liberate glucose from cellulose in biomass without the formation of fermentation inhibitors. A combination of pretreatment technologies is an alternative way to increase the access of enzymes to cellulose, and consequently, the conversion yield. In this way, the present study reports on the enzymatic hydrolysis of SCB submitted to three kinds of pretreatment: electron beam processing (EBP), and EBP followed by hydrothermal (TH) and diluted acid (AH) treatment. SCB samples were irradiated using a radiation dynamics electron beam accelerator, and then submitted to thermal and acid (0.1% sulfuric acid) hydrolysis for 40 and 60 min at 180 °C. These samples were submitted to enzymatic hydrolysis (EH) using commercial preparations, including Celluclast 1.5 L and beta-glycosidase. The addition of diluted acid improved TH treatment allowing for a shorter application time. EBP with 50 kGy increased the enzymatic hydrolysis yield of cellulose by 20% after TH and 30% after AH. - Highlights: ► We study the enzymatic hydrolysis of cellulose and hemicellulose in sugarcane bagasse. ► We study the combination of three pretreatments: electron beam processing, EBP followed by hydrothermal and by diluted acid treatment. ► The electron beam processing increased the enzymatic hydrolysis from 8% to 15% with 20 kGy. ► The enzymes used were commercial preparations, as Celluclast 1.5 L and β-glycosidase. ► The EBP with 50 kGy increased on 20% the yield of EH of cellulose after TH and 30% after AH.

  18. Scalable Machine Learning for Massive Astronomical Datasets

    Science.gov (United States)

    Ball, Nicholas M.; Gray, A.

    2014-04-01

    We present the ability to perform data mining and machine learning operations on a catalog of half a billion astronomical objects. This is the result of the combination of robust, highly accurate machine learning algorithms with linear scalability that renders the applications of these algorithms to massive astronomical data tractable. We demonstrate the core algorithms kernel density estimation, K-means clustering, linear regression, nearest neighbors, random forest and gradient-boosted decision tree, singular value decomposition, support vector machine, and two-point correlation function. Each of these is relevant for astronomical applications such as finding novel astrophysical objects, characterizing artifacts in data, object classification (including for rare objects), object distances, finding the important features describing objects, density estimation of distributions, probabilistic quantities, and exploring the unknown structure of new data. The software, Skytree Server, runs on any UNIX-based machine, a virtual machine, or cloud-based and distributed systems including Hadoop. We have integrated it on the cloud computing system of the Canadian Astronomical Data Centre, the Canadian Advanced Network for Astronomical Research (CANFAR), creating the world's first cloud computing data mining system for astronomy. We demonstrate results showing the scaling of each of our major algorithms on large astronomical datasets, including the full 470,992,970 objects of the 2 Micron All-Sky Survey (2MASS) Point Source Catalog. We demonstrate the ability to find outliers in the full 2MASS dataset utilizing multiple methods, e.g., nearest neighbors. This is likely of particular interest to the radio astronomy community given, for example, that survey projects contain groups dedicated to this topic. 2MASS is used as a proof-of-concept dataset due to its convenience and availability. These results are of interest to any astronomical project with large and/or complex

  19. GRAVITY: the VLTI 4-beam combiner for narrow-angle astrometry and interferometric imaging

    CERN Document Server

    Blind, N; Gillessen, S; Kok, Y; Lippa, M; Perrin, G; Dembet, R; Fedou, P; Lacour, S; Perraut, K; Jocou, L; Burtscher, L; Hans, O; Haug, M; Haussmann, F; Huber, S; Janssen, A; Kellner, S; Ott, T; Pfuhl, O; Sturm, E; Weber, J; Wieprecht, E; Amorim, A; Brandner, W; Straubmeier, C

    2015-01-01

    GRAVITY is the second generation Very Large Telescope Interferometer instrument for precision narrow-angle astrometry and interferometric imaging in the Near Infra-Red (NIR). It shall provide precision astrometry of order 10 microarcseconds, and imaging capability at a few milliarcsecond resolution, and hence will revolutionise dynamical measurements of celestial objects. GRAVITY is currently in the last stages of its integration and tests in Garching at MPE, and will be delivered to the VLT Interferometer (VLTI) in 2015. We present here the instrument, with a particular focus on the components making use of fibres: integrated optics beam combiners, polarisation rotators, fibre differential delay lines, and the metrology.

  20. A method of beam combination of high-power incoherent fiber laser

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Diffraction efficiency of grating plays an important role in output power of incoherent fiber laser beam combination.Through theoretic analysis and numerical simulations it has been proved that the diffraction efficiency would increase with the decrease of grating frequency and wavelength bandwidth. On the condition that the width of a fiber array is fixed at W=10 cm, an optimum grating frequency were numerically simulated as f=230 mm-1. Also an unequal interval method was proposed to improve the system efficiency of diffraction into 0.4293, which is higher than 0.3824 under the equal interval condition.

  1. JouFLU: an upgraded FLUOR beam combiner at the CHARA Array

    Science.gov (United States)

    Lhomé, E.; Scott, N.; ten Brummelaar, T.; Mollier, B.; Reess, J. M.; Chapron, F.; Buey, T.; Sevin, A.; Sturmann, J.; Sturmann, L.; Coudé du Foresto, V.

    2012-07-01

    FLUOR, which has been operational on CHARA since 2002, is an infrared fiber beam combiner. The telescope array will soon be fitted with an adaptive optics system, which will enhance the interferometer performance. In this framework, FLUOR has been entirely redeveloped and will be able to measure visibilities with higher accuracy and better sensitivity. The technical upgrades consist of improving some existing systems and developing new features. The bench, which is now remotely operable, primarily offers spectral dispersion (long fringes scanning), a more sensitive camera and a Fourier Transform Spectrometer mode. This paper presents the detailed opto-mechanical design of JouFLU (FLUOR rejuvenation), and the current instrument status.

  2. Astronomers as Software Developers

    Science.gov (United States)

    Pildis, Rachel A.

    2016-01-01

    Astronomers know that their research requires writing, adapting, and documenting computer software. Furthermore, they often have to learn new computer languages and figure out how existing programs work without much documentation or guidance and with extreme time pressure. These are all skills that can lead to a software development job, but recruiters and employers probably won't know that. I will discuss all the highly useful experience that astronomers may not know that they already have, and how to explain that knowledge to others when looking for non-academic software positions. I will also talk about some of the pitfalls I have run into while interviewing for jobs and working as a developer, and encourage you to embrace the curiosity employers might have about your non-standard background.

  3. Nanoengineered Astronomical Optics

    CERN Document Server

    Borra, E F; Bergamasco, R; Laird, P; Gingras, J; Dallaire, M; Silva, L D; Yockell-Lelievre, H

    2003-01-01

    We describe a technology for the fabrication of inexpensive and versatile mirrors through the use of a new type of nanoengineered optical material composed by the spreading of a self-assembling reflective colloidal film spread at the surface of a liquid. These new reflecting liquids offer interesting possibilities for astronomical instrumentation. For example, they can replace mercury in conventional rotating liquid mirrors. The main advantages offered include extremely low cost and, by coating a viscous liquid, the possibility of tilting the mirror by a few tens of degrees. We also have coated ferromagnetic liquids with these reflecting films. The resulting surfaces can be shaped by the application of a magnetic field, yielding reflecting surfaces that can have complicated shapes that can rapidly shift with time. These inexpensive and versatile optical elements could have numerous scientific and technological applications. Among possible astronomical applications, they could be used to make large inexpensive...

  4. VEGAS: VErsatile GBT Astronomical Spectrometer

    Science.gov (United States)

    Bussa, Srikanth; VEGAS Development Team

    2012-01-01

    The National Science Foundation Advanced Technologies and Instrumentation (NSF-ATI) program is funding a new spectrometer backend for the Green Bank Telescope (GBT). This spectrometer is being built by the CICADA collaboration - collaboration between the National Radio Astronomy Observatory (NRAO) and the Center for Astronomy Signal Processing and Electronics Research (CASPER) at the University of California Berkeley.The backend is named as VErsatile GBT Astronomical Spectrometer (VEGAS) and will replace the capabilities of the existing spectrometers. This backend supports data processing from focal plane array systems. The spectrometer will be capable of processing up to 1.25 GHz bandwidth from 8 dual polarized beams or a bandwidth up to 10 GHz from a dual polarized beam.The spectrometer will be using 8-bit analog to digital converters (ADC), which gives a better dynamic range than existing GBT spectrometers. There will be 8 tunable digital sub-bands within the 1.25 GHz bandwidth, which will enhance the capability of simultaneous observation of multiple spectral transitions. The maximum spectral dump rate to disk will be about 0.5 msec. The vastly enhanced backend capabilities will support several science projects with the GBT. The projects include mapping temperature and density structure of molecular clouds; searches for organic molecules in the interstellar medium; determination of the fundamental constants of our evolving Universe; red-shifted spectral features from galaxies across cosmic time and survey for pulsars in the extreme gravitational environment of the Galactic Center.

  5. Study of a reinforced concrete beam strengthened using a combination of SMA wire and CFRP plate

    Science.gov (United States)

    Liu, Zhi-qiang; Li, Hui

    2006-03-01

    Traditional methods used for strengthening of reinforced concrete (RC) structures, such as bonding of steel plates, suffer from inherent disadvantages. In recent years, strengthening of RC structures using carbon fiber reinforced polymer (CFRP) plates has attracted considerable attentions around the world. Most existing research on CFRP plate bonding for flexural strengthening of RC beams has been carried out for the strength enhancement. However, little research is focused on effect of residual deformations on the strengthening. The residual deformations have an important effect on the strengthening by CFRP plates. There exists a very significant challenge how the residual deformations are reduced. Shape memory alloy (SMA) has showed outstanding functional properties as an actuator. It is a possibility that SMA can be used to reduce the residual deformation and make cracks of concrete close by imposing the recovery forces on the concrete in the tensile zone. It is only an emergency damage repair since the SMA wires need to be heated continuously. So, an innovative method of a RC beam strengthened by CFRP plates in combination with SMA wires was first investigated experimentally in this paper. In addition, the nonlinear finite element software of ABAQUS was employed to further simulate the behavior of RC beams strengthened through the new strengthening method. It can be found that this is an excellent and effective strengthening method.

  6. Removal of diclofenac from surface water by electron beam irradiation combined with a biological aerated filter

    Science.gov (United States)

    He, Shijun; Wang, Jianlong; Ye, Longfei; Zhang, Youxue; Yu, Jiang

    2014-12-01

    The degradation of DCF was investigated in aqueous solution by using electron beam (EB) technology. When the initial concentration was between 10 and 40 mg/L, almost 100% of the DCF was degraded at a dose of 0.5 kGy. However, only about 6.5% of DCF was mineralized even at 2 kGy according to total organic carbon (TOC) measurements. A combined process of EB and biological aerated filter (BAF) was therefore developed to enhance the treatment of DCF contaminated surface water. The effluent quality of combined process was substantially improved by EB pretreatment due to the degradation of DCF and related intermediates. Both irradiation and biological treatment reduced the toxicity of the treated water. The experimental results showed that EB is effective for removing DCF from artificial aqueous solution and real surface water.

  7. Bi-spectral beam extraction in combination with a focusing feeder

    CERN Document Server

    Zendler, C; Nekrassov, D; Cussen, L D; Strobl, M

    2013-01-01

    Bi-spectral beam extraction combines neutrons from two different kind of moderators into one beamline, expanding the spectral range and thereby the utilization of an instrument. This idea can be realized by a mirror that reflects long wavelength neutrons from an off-axis colder moderator into a neutron guide aligned with another moderator emitting neutrons with shorter wavelengths which will be transmitted through the mirror. The mirror used in such systems is typically several meters long, which is a severe disadvantage because it reduces the possible length of a focusing device in design concepts requiring a narrow beam at a short distance from the source, as used in many instruments under development for the planned European Spallation Source (ESS). We propose a shortened extraction system consisting of several mirrors, and show that such an extraction system is better suited for combination with a feeder in an eye of the needle design, illustrated here in the context of a possible ESS imaging beamline.

  8. Bi-spectral beam extraction in combination with a focusing feeder

    Energy Technology Data Exchange (ETDEWEB)

    Zendler, C., E-mail: carolin.zendler@helmholtz-berlin.de [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); ESS Design Update Programme (Germany); Lieutenant, K.; Nekrassov, D.; Cussen, L.D. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); ESS Design Update Programme (Germany); Strobl, M. [European Spallation Source ESS AB, Box 176, 22100 Lund (Sweden)

    2013-03-11

    Bi-spectral beam extraction combines neutrons from two different kinds of moderators into one beamline, expanding the spectral range and thereby the utilization of an instrument. This idea can be realized by a mirror that reflects long wavelength neutrons from an off-axis colder moderator into a neutron guide aligned with another moderator emitting neutrons with shorter wavelengths which will be transmitted through the mirror. The mirror used in such systems is typically several meters long, which is a severe disadvantage because it reduces the possible length of a focusing device in design concepts requiring a narrow beam at a short distance from the source, as used in many instruments under development for the planned European Spallation Source (ESS). We propose a shortened extraction system consisting of several mirrors and show that such an extraction system is better suited for combination with a feeder in an eye of the needle design, illustrated here in the context of a possible ESS imaging beamline.

  9. Combining tissue-phantom ratios to provide a beam-quality specifier for flattening filter free photon beams

    International Nuclear Information System (INIS)

    Purpose: There are currently several commercially available radiotherapy treatment units without a flattening filter in the beam line. Unflattened photon beams have an energy and lateral fluence distribution that is different from conventional beams and, thus, their attenuation properties differ. As a consequence, for flattening filter free (FFF) beams, the relationship between the beam-quality specifier TPR20,10 and the Spencer–Attix restricted water-to-air mass collision stopping-power ratios, (L-/ρ)airwater, may have to be refined in order to be used with equivalent accuracy as for beams with a flattening filter. The purpose of this work was twofold. First, to study the relationship between TPR20,10 and (L-/ρ)airwater for FFF beams, where the flattening filter has been replaced by a metal plate as in most clinical FFF beams. Second, to investigate the potential of increasing the accuracy in determining (L-/ρ)airwater by adding another beam-quality metric, TPR10,5. The relationship between (L-/ρ)airwater and %dd(10)x for beams with and without a flattening filter was also included in this study. Methods: A total of 24 realistic photon beams (10 with and 14 without a flattening filter) from three different treatment units have been used to calculate (L-/ρ)airwater, TPR20,10, and TPR10,5 using the EGSnrc Monte Carlo package. The relationship between (L-/ρ)airwater and the dual beam-quality specifier TPR20,10 and TPR10,5 was described by a simple bilinear equation. The relationship between the photon beam-quality specifier %dd(10)x used in the AAPM’s TG-51 dosimetry protocol and (L-/ρ)airwater was also investigated for the beams used in this study, by calculating the photon component of the percentage depth dose at 10 cm depth with SSD 100 cm. Results: The calculated (L-/ρ)airwater for beams without a flattening filter was 0.3% lower, on average, than for beams with a flattening filter and comparable TPR20,10. Using the relationship in IAEA, TRS-398

  10. Combined microwave and electron beam exposure facilities for medical studies and applications.

    Science.gov (United States)

    Martin, Diana; Cinca, Sabin; Margaritescu, Irina; Neagu, Monica; Iacob, Nicusor; Ighigeanu, Daniel; Matei, Constantin; Craciun, Gabriela; Manaila, Elena; Chirita, Doru Aurel; Moisescu, Mihaela

    2009-01-01

    The paper presents two radiation exposure facilities (REFs) which permit separate and simultaneous irradiation with microwaves (MW) of 2.45 GHz and electron beams (EB) of 6.23 MeV for malignant melanoma (MM) cell investigations, in vitro (MW+EB-REF-vitro) and in vivo (MW+EB-REF-vivo). The REFs are specifically designed for the following medical studies: 1) The effects of separate and combined (successive and simultaneous) MW and EB irradiation on the B16F10 mouse--MM cell cultures without/with drugs incubation, 2) The effects of separate and combined MW and EB irradiation on human blood components irradiated in samples of integral blood from healthy donors and from donors with MM; 3) The effects of separate and combined MW and EB whole body irradiation on the C57 BL/6 mice bearing MM without/with drugs administration. Several representative results obtained by experiments with REFs in vitro and in vivo are discussed. The most important conclusion of the experimental results is that low dose-total body MW+EB irradiation combined with drugs administration could present a valuable potential for an advanced study in malignant melanoma therapy. PMID:21384705

  11. Clinical evaluation of external beam radiotherapy combined with arterial infusion chemotherapy for advanced oral tongue cancer

    International Nuclear Information System (INIS)

    Clinical results of external beam radiotherapy combined with arterial infusion chemotherapy for advanced oral tongue cancer were analyzed. Forty patients with oral tongue squamous cell carcinoma underwent these combined therapy in the period between 1985 and 1996. Subject include 17 males and 23 females. Ages ranged from 27 to 84; median age was 64.2. The size of primary lesion was classified as follows: T1: 2 cases, T2: 16 cases, T3: 21 cases, T4: 1 case. Sixteen patients were treated as radical therapy, 24 as preoperative therapy. Anti-cancer drugs used for arterial infusion were 5-FU (31 patients) or CBDCA (9 patients). For 16 radical cases, ten (62.5%) were CR (tumor disappeared). In 4 cases (25.0%), tumor volume was decreased above 50%, but in 2 (12.5%) any local effect could not be confirmed. For 24 pre-operative cases, Complete Response (CR) was observed only in 12.5% (3 patients). Partial Response (PR) was observed in 15 patients (62.5%), no change (NC) in 6 (25.0%). In 6 from 15 PR cases disappearance of viable atypical cells could be confirmed from histological examinations of resected tongue. In results local control rate (CR rate) for 24 pre-operative cases was 37.5% (9/24). Severe complications, for examples ulcerations of the tongue or exposure of the mandible could not be found in any cases. CR was observed in 19 patients (47.5%) out of 40, and severe late complications were noted in no patients. External beam radiotherapy combined with arterial infusion chemotherapy was effective for locally advanced cancer of anterior two-thirds of the tongue. (author)

  12. The Biographical Encyclopedia of Astronomers

    CERN Document Server

    Hockey, Thomas; Williams, Thomas R; Bracher, Katherine; Jarrell, Richard A; Marché, Jordan D; Ragep, F. Jamil; Palmeri, JoAnn; Bolt, Marvin

    2007-01-01

    The Biographical Encyclopedia of Astronomers is a unique and valuable resource for historians and astronomers alike. The two volumes include approximately 1550 biographical sketches on astronomers from antiquity to modern times. It is the collective work of about 400 authors edited by an editorial board of 9 historians and astronomers, and provides additional details on the nature of an entry and some summary statistics on the content of entries. This new reference provides biographical information on astronomers and cosmologists by utilizing contemporary historical scholarship. Individual entries vary from 100 to 1500 words, including the likes of the superluminaries such as Newton and Einstein, as well as lesser-known astronomers like Galileo's acolyte, Mario Guiducci. A comprehensive contributor index helps researchers to identify the authors of important scientific topics and treatises.

  13. Remediation of textiles wastewater using coagulant and electron beam irradiation, as separate and combination of treatments

    International Nuclear Information System (INIS)

    Chemical treatment is one of the method that often been used to treat textiles wastewater. However this method created sludge as a secondary waste. In these study textiles wastewater was treated with three different methods; chemical treatment, electron beam treatment and combination of both treatments. The objective is to investigate the effectiveness of each treatment. Coagulant of Al2(SO4)3(8%) and PAC(16-18%) react effectively with textiles wastewater at pH 6 while optimum dosage required was 0.1ml/15 ml of sample and 0.5ml/15 ml sample respectively. BOD decreases at each treatment and significant value was shown in combination irradiation and chemical treatment. BOD reduce about 32% by irradiation,53-56% by coagulant and 62-77% in combination treatment. COD also decreases at each treatment method except when PAC was used to treat irradiated sample at irradiation parameter of 1MeV, 5mA, 50kGy and 2 MeV,1mA,10 kGy, where the COD increases. (Author)

  14. TESTBEAM COORDINATION: 2nd ATLAS H8 Combined Test Beam Workshop

    CERN Multimedia

    Di Girolamo, B

    The second ATLAS H8 Combined Test Beam Workshop took place at CERN on 24th and 25th November. After a first workshop in July to warm up the atmosphere, a lot of work has been done in the meantime and there was a clear need to get together again before the end of 2003. The morning of the first day has been devoted to an assessment of the status of the various elements needed for next year’s test beam in H8. Each sub-detector has been presenting the status of preparation, as well as the work in progress and still to be done. The picture has been completed with the first plans for the DAQ from the point of view of the sub-detectors requirements, and a status of the LVL1 elements. Finally, the status and the timescale for availability of the LVL2 and EF infrastructure have been presented. The final draft layout of the sub-detectors has been discussed (figures 1 and 2). A more detailed description of the layout is in preparation to include more information on dead material and on the ancillary detectors (scint...

  15. Application of electron beam irradiation combined to conventional treatment to treat industrial effluents

    Science.gov (United States)

    Duarte, C. L.; Sampa, M. H. O.; Rela, P. R.; Oikawa, H.; Cherbakian, E. H.; Sena, H. C.; Abe, H.; Sciani, V.

    2000-03-01

    A preliminary study to combine electron beam irradiation process with biological treatment was carried out. Experiments were conducted using samples from a governmental wastewater treatment plant (WTP) that receives about 20% of industrial wastewater, with the objective of destroying the refractory organic pollutants and to obtain a better performance of this plant. Samples from five different steps of WTP were collected and irradiated in the electron beam accelerator in a batch system with 5.0, 10.0 and 20.0 kGy doses. The main results showed a removal of 99% of all organic compound analysed in the industrial receiver unit (IRU) effluent and in the coarse bar screen (CBS) effluent with a 20 kGy dose, and for the medium bar screen (MBS) and primary sedimentation (PS) effluent a 10 kGy dose was sufficient. In the case of final effluent (FE), a dose of 5 kGy removed the remaining organic compounds and dyes present after biological treatment.

  16. Electron beam combined with hydrothermal treatment for enhancing the enzymatic convertibility of sugarcane bagasse

    Science.gov (United States)

    Duarte, C. L.; Ribeiro, M. A.; Oikawa, H.; Mori, M. N.; Napolitano, C. M.; Galvão, C. A.

    2012-08-01

    The use of microbial cellulolytic enzymes is the most efficient process to liberate glucose from cellulose in biomass without the formation of fermentation inhibitors. A combination of pretreatment technologies is an alternative way to increase the access of enzymes to cellulose, and consequently, the conversion yield. In this way, the present study reports on the enzymatic hydrolysis of SCB submitted to three kinds of pretreatment: electron beam processing (EBP), and EBP followed by hydrothermal (TH) and diluted acid (AH) treatment. SCB samples were irradiated using a radiation dynamics electron beam accelerator, and then submitted to thermal and acid (0.1% sulfuric acid) hydrolysis for 40 and 60 min at 180 °C. These samples were submitted to enzymatic hydrolysis (EH) using commercial preparations, including Celluclast 1.5 L and beta-glycosidase. The addition of diluted acid improved TH treatment allowing for a shorter application time. EBP with 50 kGy increased the enzymatic hydrolysis yield of cellulose by 20% after TH and 30% after AH.

  17. Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Labuda, Aleksander; Proksch, Roger [Asylum Research an Oxford Instruments Company, Santa Barbara, California 93117 (United States)

    2015-06-22

    An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community.

  18. 3D imaging using combined neutron-photon fan-beam tomography: A Monte Carlo study.

    Science.gov (United States)

    Hartman, J; Yazdanpanah, A Pour; Barzilov, A; Regentova, E

    2016-05-01

    The application of combined neutron-photon tomography for 3D imaging is examined using MCNP5 simulations for objects of simple shapes and different materials. Two-dimensional transmission projections were simulated for fan-beam scans using 2.5MeV deuterium-deuterium and 14MeV deuterium-tritium neutron sources, and high-energy X-ray sources, such as 1MeV, 6MeV and 9MeV. Photons enable assessment of electron density and related mass density, neutrons aid in estimating the product of density and material-specific microscopic cross section- the ratio between the two provides the composition, while CT allows shape evaluation. Using a developed imaging technique, objects and their material compositions have been visualized. PMID:26953978

  19. Quantitative measurements of electromechanical response with a combined optical beam and interferometric atomic force microscope

    International Nuclear Information System (INIS)

    An ongoing challenge in atomic force microscope (AFM) experiments is the quantitative measurement of cantilever motion. The vast majority of AFMs use the optical beam deflection (OBD) method to infer the deflection of the cantilever. The OBD method is easy to implement, has impressive noise performance, and tends to be mechanically robust. However, it represents an indirect measurement of the cantilever displacement, since it is fundamentally an angular rather than a displacement measurement. Here, we demonstrate a metrological AFM that combines an OBD sensor with a laser Doppler vibrometer (LDV) to enable accurate measurements of the cantilever velocity and displacement. The OBD/LDV AFM allows a host of quantitative measurements to be performed, including in-situ measurements of cantilever oscillation modes in piezoresponse force microscopy. As an example application, we demonstrate how this instrument can be used for accurate quantification of piezoelectric sensitivity—a longstanding goal in the electromechanical community

  20. JouFLU: upgrades to the fiber linked unit for optical recombination (FLUOR) interferometric beam combiner.

    Science.gov (United States)

    Scott, N. J.; Lhomé, E.; ten Brummelaar, T. A.; Coudé du Foresto, V.; Millan-Gabet, R.; Sturmann, J.; Sturmann, L.

    2014-07-01

    The Fiber Linked Unit for Optical Recombination (FLUOR) is a precision interferometric beam combiner operating at the CHARA Array on Mt. Wilson, CA. It has recently been upgraded as part of a mission known as "Jouvence of FLUOR" or JouFLU. As part of this program JouFLU has new mechanic stages and optical payloads, new alignment systems, and new command/control software. Furthermore, new capabilities have been implemented such as a Fourier Transform Spectrograph (FTS) mode and spectral dispersion mode. These upgrades provide new capabilities to JouFLU as well as improving statistical precision and increasing observing efficiency. With these new systems, measurements of interferometric visibility to the level of 0.1% precision are expected on targets as faint as 6th magnitude in the K band. Here we detail the upgrades of JouFLU and report on its current status.

  1. Jouvence of Fluor: Upgrades of a Fiber Beam Combiner at the CHARA Array

    Science.gov (United States)

    Scott, N. J.; Millan-Gabet, R.; Lhomé, E.; Ten Brummelaar, T. A.; Coudé Du Foresto, V.; Sturmann, J.; Sturmann, L.

    The FLUOR (Fiber Linked Unit for Optical Recombination) interferometric beam combiner located at the CHARA Array on Mt. Wilson, California has recently undergone a program of major upgrades known as Jouvence of FLUOR (JouFLU). These upgrades seek to improve the precision, use, and observing efficiency of FLUOR as well as introduce new modes of operation. A Fourier Transform Spectrograph (FTS) mode and a spectral dispersion mode have been added to improve calibration and data collection. New mechanized stages and new cameras have been added to FLUOR for alignment and pupil plane imaging. Entirely new control/command software has been written for FLUOR which brings it into compliance with CHARA software standards. This allows for continued software upgrades and full remote operation capability. The new JouFLU instrument is now operating on sky and is expected to achieve accurate interferometric visibility amplitude measurements with 0.1 to 0.3% precision.

  2. Research On Degradation Of Silk Fibroin By Combination Of Electron Beam Irradiation And Hydrothermal Processing

    International Nuclear Information System (INIS)

    Silk fibers and silk proteins have been demonstrated to be useful to apply in the textile industry, biomedical, cosmetics, pharmaceuticals. In this study, the effects of electron beam (EB) irradiation combined with hydrothermal processing to the solubility of silk fibroin and generation of soluble silk protein were investigated. The solubility of unirradiated and irradiated fibroin were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The protein content increased from 0.4617 to 0.6530 mg/mg when irradiation doses increased from 0 to 200 kGy, respectively. The molecular weight of protein was determined by SDS-PAGE method. The characteristics of silk protein were confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). (author)

  3. Collaborative Astronomical Image Mosaics

    CERN Document Server

    Katz, Daniel S; Mann, Robert G

    2010-01-01

    This chapter describes how astronomical imaging survey data have become a vital part of modern astronomy, how these data are archived and then served to the astronomical community through on-line data access portals. The Virtual Observatory, now under development, aims to make all these data accessible through a uniform set of interfaces. This chapter also describes the scientific need for one common image processing task, that of composing individual images into large scale mosaics and introduces Montage as a tool for this task. Montage, as distributed, can be used in four ways: as a single thread/process on a single CPU, in parallel using MPI to distribute similar tasks across a parallel computer, in parallel using grid tools (Pegasus/DAGMan) to distributed tasks across a grid, or in parallel using a script-driven approach (Swift). An on-request web based Montage service is available for users who do not need to build a local version. We also introduce some work on a new scripted version of Montage, which o...

  4. Grigor Narekatsi's astronomical insights

    Science.gov (United States)

    Poghosyan, Samvel

    2015-07-01

    What stand out in the solid system of Gr. Narekatsi's naturalistic views are his astronomical insights on the material nature of light, its high speed and the Sun being composed of "material air". Especially surprising and fascinating are his views on stars and their clusters. What astronomers, including great Armenian academician V. Ambartsumian (scattering of stellar associations), would understand and prove with much difficulty thousand years later, Narekatsi predicted in the 10th century: "Stars appear and disappear untimely", "You who gather and scatter the speechless constellations, like a flock of sheep". Gr. Narekatsti's reformative views were manifested in all the spheres of the 10th century social life; he is a reformer of church life, great language constructor, innovator in literature and music, freethinker in philosophy and science. His ideology is the reflection of the 10th century Armenian Renaissance. During the 9th-10th centuries, great masses of Armenians, forced to migrate to the Balkans, took with them and spread reformative ideas. The forefather of the western science, which originated in the period of Reformation, is considered to be the great philosopher Nicholas of Cusa. The study of Gr. Narekatsti's logic and naturalistic views enables us to claim that Gr. Narekatsti is the great grandfather of European science.

  5. Really Bad Astronomers

    Science.gov (United States)

    Hockey, Thomas A.

    2009-01-01

    What happens when even Percival Lowell stops believing in your Mars observations? History can be troubling. This I learned while editing the Biographical Encyclopedia of Astronomers (Springer, 2007). There have been astronomers who do not fit our commonly held, and clung to, conceptual model: a sociological system that sifts out generally like-minded and sensible colleagues. I refer to those individuals who (for at least a time) successfully entered the mainstream profession, but now disturb our worldview that says prosperity as a scientist usually is achieved by a rational being holding certain common values. My List of Shame includes examples from each of the last four centuries. Not "crack pot” cosmologists, these were hard-working observers for whom the end justified the means. And they all got away with it. Each person I discuss was vetted by the professional establishment of the day. Yet you will learn how to be fired from a major observatory, banned from prominent journals. But only after damage to the science is done. Be afraid.

  6. Combining tissue-phantom ratios to provide a beam-quality specifier for flattening filter free photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Dalaryd, Mårten, E-mail: Marten.Dalaryd@med.lu.se; Knöös, Tommy [Department of Clinical Sciences, Medical Radiation Physics, Lund University, P.O. Box 117, Lund SE-221 00, Sweden and Radiation Physics, Skåne University Hospital, Lund SE-221 85 (Sweden); Ceberg, Crister [Department of Clinical Sciences, Medical Radiation Physics, Lund University, P.O. Box 117, Lund SE-221 00 (Sweden)

    2014-11-01

    Purpose: There are currently several commercially available radiotherapy treatment units without a flattening filter in the beam line. Unflattened photon beams have an energy and lateral fluence distribution that is different from conventional beams and, thus, their attenuation properties differ. As a consequence, for flattening filter free (FFF) beams, the relationship between the beam-quality specifier TPR{sub 20,10} and the Spencer–Attix restricted water-to-air mass collision stopping-power ratios, (L{sup -}/ρ){sub air}{sup water}, may have to be refined in order to be used with equivalent accuracy as for beams with a flattening filter. The purpose of this work was twofold. First, to study the relationship between TPR{sub 20,10} and (L{sup -}/ρ){sub air}{sup water} for FFF beams, where the flattening filter has been replaced by a metal plate as in most clinical FFF beams. Second, to investigate the potential of increasing the accuracy in determining (L{sup -}/ρ){sub air}{sup water} by adding another beam-quality metric, TPR{sub 10,5}. The relationship between (L{sup -}/ρ){sub air}{sup water} and %dd(10){sub x} for beams with and without a flattening filter was also included in this study. Methods: A total of 24 realistic photon beams (10 with and 14 without a flattening filter) from three different treatment units have been used to calculate (L{sup -}/ρ){sub air}{sup water}, TPR{sub 20,10}, and TPR{sub 10,5} using the EGSnrc Monte Carlo package. The relationship between (L{sup -}/ρ){sub air}{sup water} and the dual beam-quality specifier TPR{sub 20,10} and TPR{sub 10,5} was described by a simple bilinear equation. The relationship between the photon beam-quality specifier %dd(10){sub x} used in the AAPM’s TG-51 dosimetry protocol and (L{sup -}/ρ){sub air}{sup water} was also investigated for the beams used in this study, by calculating the photon component of the percentage depth dose at 10 cm depth with SSD 100 cm. Results: The calculated (L{sup -}/

  7. Combining the switched-beam and beam-steering capabilities in a 2-D phased array antenna system

    Science.gov (United States)

    Tsai, Yi-Che; Chen, Yin-Bing; Hwang, Ruey-Bing

    2016-01-01

    This paper presents the development, fabrication, and measurement of a novel beam-forming system consisting of 16 subarray antennas, each containing four aperture-coupled patch antennas, and the application of this system in smart wireless communication systems. The beam patterns of each of the subarray antennas can be switched toward one of nine zones over a half space by adjusting the specific phase delay angles among the four antenna elements. Furthermore, when all subarrays are pointed at the same zone, slightly continuous beam steering in around 1° increments can be achieved by dynamically altering the progressive phase delay angle among the subarrays. Phase angle calibration was implemented by coupling each transmitter output and down converter into the in-phase/quadrature baseband to calculate the correction factor to the weight. In addition, to validate the proposed concepts and the fabricated 2-D phased array antenna system, this study measured the far-field radiation patterns of the aperture-coupled patch array integrated with feeding networks and a phase-calibration system to carefully verify its spatially switched-beam and beam-steering characteristics at a center frequency of 2.4 GHz which can cover the industrial, scientific, and medical band and some long-term evolution applications. In addition, measured results were compared with calculated results, and agreement between them was observed.

  8. Incoherent and coherent beam combination for master oscillator/power amplifier system with stimulated Brillouin scattering mirror

    Institute of Scientific and Technical Information of China (English)

    Fu Shi-You; Tian Zhao-Shuo; Shi Xiao-Li; Sun Zheng-He

    2008-01-01

    In this paper,we studied incoherent and coherent beam combining for the master oscillator/power amplifier (MOPA) system with stimulated Brillouin scattering (SBS) mirror.Optic field intensity distributions in the near and fax field are numerically calculated for the two kinds of system.The results show that good beam quality in the far field could be obtained.It provides a theoretical basis for experimental research in the future.

  9. Care of astronomical telescopes and accessories a manual for the astronomical observer and amateur telescope maker

    CERN Document Server

    Pepin, M Barlow

    2006-01-01

    This is complete guide for anyone who wants to understand more than just the basics of astronomical telescopes and accessories, and how to maintain them in the peak of condition. The latest on safely adjusting, cleaning, and maintaining your equipment is combined with thoroughly updated methods from the old masters.

  10. Compression of interferometric radio-astronomical data

    CERN Document Server

    Offringa, A R

    2016-01-01

    The volume of radio-astronomical data is a considerable burden in the processing and storing of radio observations with high time and frequency resolutions and large bandwidths. Lossy compression of interferometric radio-astronomical data is considered to reduce the volume of visibility data and to speed up processing. A new compression technique named "Dysco" is introduced that consists of two steps: a normalization step, in which grouped visibilities are normalized to have a similar distribution; and a quantization and encoding step, which rounds values to a given quantization scheme using a dithering scheme. Several non-linear quantization schemes are tested and combined with different methods for normalizing the data. Four data sets with observations from the LOFAR and MWA telescopes are processed with different processing strategies and different combinations of normalization and quantization. The effects of compression are measured in image plane. The noise added by the lossy compression technique acts ...

  11. Highly Repetitive Laser Inertial fusion driver with Tiled Coherent Beam Combination Laser using Stimulated Brillouin Scattering Phase Conjugation Mirrors

    International Nuclear Information System (INIS)

    Full text: In these days, the energy problem is serious in the world. It is necessary to develop a new source of the sustainable energy. In these sustainable energy sources, fusion energy is the most promised energy source. Especially, the laser inertial fusion energy is easy to maintain and easy to increase its scale. However, there are 3 hot problems to achieve the laser inertial fusion energy. To achieve the LIFE, it is necessary to develop 2.5 kJ/10 ns at 10 Hz laser. The Second problem is target injection with high repetition rate and high accuracy. We need to inject the fuel target to the centre of a chamber with accuracy to 20 μm after the fusion reaction. The third problem is the target window coating due to debris from the target implosion. The first and the second problems can be resolved simply by coherent beam combination laser using Stimulated Brillouin Scattering Phase Conjugation Mirrors (SBS-PCM). The 4-beam combination system is built to prove its feasibility to laser inertial fusion energy driver. The input energy of the each sub-beam is 1.032 ± 0.027 mJ, and the output energy of sub-beam is 402.3 ± 1.21 mJ. The standard deviations of the phase differences between the reference beam and other beams were measured to be less than λ/13, during 2,500 shots (250 s), and we will get it better than λ/20 soon. The coherent beam combination using SBS-PCM has additional advantages in LIFE reactor system. In the fusion reaction, target injection is one of the serious problems. The repetition rate of the target injection is ∼ 10 Hz, and the target speed is around 400 m/s. We need the accuracy of target position to 20 μm. Because of the turbulent flow after the prior fusion reaction, it is impossible to inject the target with the accuracy to more than 20 μm. This method can give the accuracy to less than 1 μm even when the turbulence exists in the reactor chamber. In this paper, the authors introduce the tiled coherent beam combining laser using SBS

  12. The SIMBAD astronomical database

    CERN Document Server

    Wenger, M; Egret, D; Dubois, P; Bonnarel, F; Borde, S; Genova, F; Jasniewicz, G; Laloe, S; Lesteven, S; Monier, R; Wenger, Marc; Ochsenbein, Francois; Egret, Daniel; Dubois, Pascal; Bonnarel, Francois; Borde, Suzanne; Genova, Francoise; Jasniewicz, Gerard; Laloe, Suzanne; Lesteven, Soizick; Monier, Richard

    2000-01-01

    Simbad is the reference database for identification and bibliography ofastronomical objects. It contains identifications, `basic data', bibliography,and selected observational measurements for several million astronomicalobjects. Simbad is developed and maintained by CDS, Strasbourg. Building thedatabase contents is achieved with the help of several contributing institutes.Scanning the bibliography is the result of the collaboration of CDS withbibliographers in Observatoire de Paris (DASGAL), Institut d'Astrophysique deParis, and Observatoire de Bordeaux. When selecting catalogues and tables forinclusion, priority is given to optimal multi-wavelength coverage of thedatabase, and to support of research developments linked to large projects. Inparallel, the systematic scanning of the bibliography reflects the diversityand general trends of astronomical research. A WWW interface to Simbad is available at: http://simbad.u-strasbg.fr/Simbad

  13. Astronomical tides and earthquakes

    Science.gov (United States)

    Wu, Xiaoping; Mao, Wei; Huang, Yong

    2001-03-01

    A review on the studies of correlation between astronomical tides and earthquakes is given in three categories, including (1) earthquakes and the relative locations of the sun, the moon and the earth, (2) earthquakes and the periods and phases of tides and (3) earthquakes and the tidal stress. The first two categories mainly investigate whether or not there exist any dominant pattern of the relative locations of the sun, the moon and the earth during earthquakes, whether or not the occurrences of earthquakes are clustered in any special phase during a tidal period, whether or not there exists any tidal periodic phenomenon in seismic activities, By empasizing the tidal stress in seismic focus, the third category investigates the relationship between various seismic faults and the triggering effects of tidal stress, which reaches the crux of the issue. Possible reasons to various inconsistent investigation results by using various methods and samples are analyzed and further investigations are proposed.

  14. MRI of the prostate after combined radiotherapy (interstitial with external beam irradiation): histopathological correlation

    International Nuclear Information System (INIS)

    Aim: To identify the MRI changes of the prostate after combined (high-dose rate interstitial with external beam) radiotherapy for, localized prostate cancer and to correlate the findings with histology in order to determine the value of MR imaging in the follow-up of these patients. Material and methods: Twenty-three patients underwent MR imaging at 1.5 T between 6 and 24 months after completion of combined radiotherapy. The prostate was imaged with axial and coronal T2-weighted sequences and axial T1-weighted sequences before and after intravenous administration of Gd-DTPA. Quandrant or sextant biopsy was performed in all cases and three patients with proven persistence of the tumor underwent salvage prostatectomy. The MRI findings were compared with the biopsy results or the large-area sections. Results: On T2-weighted images the fibrotically changed peripheral zone was hypointense while persistent tumor tissue showed hyperintensity. Solid tumors were depicted when they had a diameter of 1 cm or more. Persistent tumors of the diffuse multifocal type escaped detection. Contrast-enhanced T1-weighted imaging yielded no additional information. The accuracy in detecting persistent tumor was 74%. Conclusions: Histopathologic changes seen after combined radiotherapy correlate with the findings on T2-weighted MR images. MR imaging cannot replace follow-up by routine biopsy. Its only role is assessing local operability in cases found to have increasing PSA levels during follow-up. Further studies are needed to determine the role of MR imaging in this patient population. (orig.)

  15. Structure and properties of combined protective coatings with use high-current electron beam irradiation

    International Nuclear Information System (INIS)

    Full text: Improvement of superficial materials and products is the important task. The high-efficiency vacuum - arc sources created recently open more ample opportunities for change of properties of a surface of metal materials. Now there is a number of known technologies on drawing coverings for updating a surface of working parts of metals. Today the protecting coatings, which were deposited on tools applied in electrochemical and chemical devices, acquired a great interest. It is known that some kinds of treatment, such as, for example, ion implantation, ion-assisted deposition of thin films, electron beam irradiation, CVD, PVD, etc. cannot result directly in desired effect. Therefore to resolve some application problems, one has to use combined methods of treatment, which allow one to resolve complicated serious problems of material science and industrial fields, for example, in space, automobile, aviation, ship building, etc. So, the goal of this work was to study the structure, element composition and properties of hybrid coatings on TiNi/Cr/Al2O3 and TiN/Al2O3 base, which were deposited on AISI 321 stainless steel before and after electron beam irradiation. A special attention was paid to studies of diffusion and mass-transfer processes. We applied XRD, RBS, AES, SEM with micro-analysis as well as corrosion in sulfur acid, adhesion and hardness tests. It had been demonstrated that these coatings were able to perform different functions as protecting coatings. Tests of TiN/Al2O3 and TiN/Cr/Al2O3 coatings, which were deposited on AISI 321 steel, after high-current electron beam irradiation demonstrated significant increase in corrosion resistance in H2SO4 solution under 4000C temperature. Hardness and adhesion of these coatings to substrate increased, and significant decrease in friction wear of coating surfaces was found. In such a way, in this report it was demonstrated that hybrid coatings on TiN/Cr/Al2O3 and TiN/Al2O3 base after HCEB irradiation under

  16. The effects of combined electron beam irradiation and microwave heating on microorganisms inactivation

    International Nuclear Information System (INIS)

    The comparative results obtained by applying electron beam irradiation (EBI), microwave heating (MH) and combined EBI and MH (successive or simultaneous) to the reduction of Staphylococcus intermedius and Pseudomaonas aeruginosa cells are presented. Both gamma and electron beam radiation processes are used now commercially for microorganisms sterilization because the ionizing radiations are capable, in adequate doses, to destroy all forms of life. However, high doses are required for the sterilization process. In this respect the possibility of reduction of these doses is a very attractive prospect. A new method, which is still under research and development, is based on the use of microwaves. The microwave sterilization effect is explained by their heating property on polar or polarizable molecules of biological systems. The mild thermal treatment using MWH in addition to EBI could be considered to be sufficient for complete sterilization of a wide variety of materials including foods and medical objects. Our experiments demonstrated that the separate, successive and simultaneous EBI and MH have no the same effect to the microorganisms reduction. The simultaneous EBI and MH cause greater lethal effects than their separate or successive application. Thus, the number of viable colony forming units per ml (CFU/ml) of Staphylococcus intermedius was as follows: 3x1014 CFU/ml for the unirradiated sample; 5.3x109 CFU/ml for electron beam irradiation with 600 Gy; 3.3x109 CFU/ml for 15 s microwave heating up to 45 deg C; 4.1x107 CFU/ml for successive irradiation - first 600 Gy electrons and then 15 s microwave heating up to 45 deg C; 2.45x105 CFU/ml for successive irradiation - first 15 s microwave heating up to 45 deg C and then 600 Gy electrons; 1.8x104 CFU/ml for simultaneous irradiation with 600 Gy electrons and 15 s microwave heating up to 45 deg C. Experiments were carried out using an electron linear accelerator of 6 MeV and 0.18 kW, a 2.45 GHz microwave source of

  17. Visualizing Astronomical Data with Blender

    CERN Document Server

    Kent, Brian R

    2013-01-01

    Astronomical data take on a multitude of forms -- catalogs, data cubes, images, and simulations. The availability of software for rendering high-quality three-dimensional graphics lends itself to the paradigm of exploring the incredible parameter space afforded by the astronomical sciences. The software program Blender gives astronomers a useful tool for displaying data in a manner used by three-dimensional (3D) graphics specialists and animators. The interface to this popular software package is introduced with attention to features of interest in astronomy. An overview of the steps for generating models, textures, animations, camera work, and renders is outlined. An introduction is presented on the methodology for producing animations and graphics with a variety of astronomical data. Examples from sub-fields of astronomy with different kinds of data are shown with resources provided to members of the astronomical community. An example video showcasing the outlined principles and features is provided along w...

  18. Electromagnetic design and development of a combined function horizontal and vertical dipole steerer magnet for medium energy beam transport line

    International Nuclear Information System (INIS)

    Medium Energy Beam Transport (MEBT) line is required to match the optical functions between the RFQ and SRF cavities/DTL cavities.The primary function of the MEBT lines is to keep the emittance growth of the output beam as low as possible in a highly space charge environment at low energies. The transverse focusing of the beam is achieved by strong focusing quadrupoles and the longitudinal dynamics is achieved by the buncher cavities. The Dipole Steerers serve the function of a control element to achieve the desired transverse beam position. To minimize the emittance growth high magnetic field rigidity is required in a highly constrained longitudinal space for these corrector magnets. The design and development of an air-cooled dipole steerer magnet has been done for an integral dipole field of 2.1mT-m in a Good Field Region (GFR) of 23 mm diameter with Integral Field homogeneity better than 0.5%. Electromagnetic field simulations were done using 3D-FEM simulation software OPERA. Error sensitivity studies have been carried out to specify the manufacturing tolerances to estimate and minimize the beam transmission loss due to likely misalignments and rotation of the magnet. A combined function dipole corrector magnet has been designed and fabricated at the Control Instrumentation Division, BARC. This paper discusses measurement results of a combined function dipole steerer for MEBT line for Proton (H+) beam at 2.5 MeV. (author)

  19. IEC 61267: Feasibility of type 1100 aluminium and a copper/aluminium combination for RQA beam qualities.

    Science.gov (United States)

    Leong, David L; Rainford, Louise; Zhao, Wei; Brennan, Patrick C

    2016-01-01

    In the course of performance acceptance testing, benchmarking or quality control of X-ray imaging systems, it is sometimes necessary to harden the X-ray beam spectrum. IEC 61267 specifies materials and methods to accomplish beam hardening and, unfortunately, requires the use of 99.9% pure aluminium (Alloy 1190) for the RQA beam quality, which is expensive and difficult to obtain. Less expensive and more readily available filters, such as Alloy 1100 (99.0% pure) aluminium and copper/aluminium combinations, have been used clinically to produce RQA series without rigorous scientific investigation to support their use. In this paper, simulation and experimental methods are developed to determine the differences in beam quality using Alloy 1190 and Alloy 1100. Additional simulation investigated copper/aluminium combinations to produce RQA5 and outputs from this simulation are verified with laboratory tests using different filter samples. The results of the study demonstrate that although Alloy 1100 produces a harder beam spectrum compared to Alloy 1190, it is a reasonable substitute. A combination filter of 0.5 mm copper and 2 mm aluminium produced a spectrum closer to that of Alloy 1190 than Alloy 1100 with the added benefits of lower exposures and lower batch variability. PMID:26776501

  20. Human perception of indoor environment generated by chilled ceiling combined with mixing ventilation or localised chilled beam under cooling mode

    DEFF Research Database (Denmark)

    Bolashikov, Zhecho Dimitrov; Nygaard, Linette; Uth, Simon C.;

    2014-01-01

    Experiments with 24 subjects were performed to study and compare the human perception of the indoor environment under summer conditions generated by a chilled ceiling combined with overhead mixing ventilation and localised chilled beam. The experiments were performed in an experimental chamber (4...... simulate direct solar load on the floor (270 W). The total heat load in the room was 56 W/m2. The air temperature around the workstation by the window was kept either 26 or 28 oC. The supplied air by the overhead mixing ventilation and the primary supply air of the localised chilled beam was kept at 13 L....../s and 16 0C. The localised chilled beam was installed over the workstation placed by the simulated window. During the experiment the subjects were delegated control over the primary flow rate supplied by the localised chilled beam. The whole exposure lasted 2 hours with 30 min of acclimatisation before...

  1. Ultrashort broadband polarization beam splitter based on a combined hybrid plasmonic waveguide

    Science.gov (United States)

    Chang, Ken-Wei; Huang, Chia-Chien

    2016-01-01

    We propose an ultracompact broadband polarization beam splitter (PBS) based on a combined hybrid plasmonic waveguide (HPW). The proposed PBS separates transverse-electric (TE) and transverse-magnetic (TM) modes using a bent lower HPW with vertical nanoscale gaps and a straight upper HPW with a horizontal nanoscale gap, respectively, without relying on an additional coupling region. This design considerably reduces the length of the PBS to the submicron scale (920 nm, the shortest PBS reported to date) while offering polarization extinction ratios (PERs) of ~19 dB (~18 dB) and insertion losses (ILs) of ~0.6 dB (~0.3 dB) for the TE (TM) mode over an extremely broad band of 400 nm (from λ = 1300 nm to 1700 nm, covering entirely second and third telecom windows). The length of the designed PBS can be reduced further to 620 nm while still offering PERs of 15 dB, realizing a densely photonic integrated circuit. Considering the fabrication tolerance, the designed PBS allows for large geometrical deviations of ±20 nm while restricting PER variations to within 1 dB, except for those in the nanoscale gaps smaller than 10nm. Additionally, we also address the input and ouput coupling efficiencies of the proposed PBS.

  2. Gold nanopillar arrays as biosensors fabricated by electron beam lithography combined with electroplating.

    Science.gov (United States)

    Liu, Jianpeng; Zhang, Sichao; Ma, Yaqi; Shao, Jinhai; Lu, Bingrui; Chen, Yifang

    2015-03-20

    We report our work on the development of subwavelength gold pillar arrays as local surface plasmonic (LSP) resonators for sensor applications. These arrays are fabricated by electron beam lithography combined with electroplating. The conical shape, instead of flat one, on the top of Au pillars, induced by uneven current density in the plating, may affect the LSP resonance (LSPR). This paper aims to carry out a systematic study of LSPR behavior in nanopillar arrays with both flat and conical shapes on the top, trying to prove the feasibility of the developed nanoprocess. Both numerical simulations by the finite-difference time-domain (FDTD) method and experimental characterization on fabricated LSP resonators for reflectance spectra were carried out. Our experiments indicate that the fabricated nanopillar arrays in Au demonstrate the promising capability of refractive index sensing with sensitivity of 270 nm/refractive index unit. FDTD simulation of electric field density in the gap between pillars reveals the correlation between the resonant absorption of the incident light and the standing waves of localized surface plasmon polaritons in the gaps of the pillar array, despite the conical shape of the pillars. Moreover, it was discovered that the resonant absorption becomes stronger when the light incident angle is increased. The proposed nanoprocess for pillar arrays should possess great prospects for manufacturing Au pillars with high aspect ratio for achieving higher sensitivity at an economical cost. PMID:25968546

  3. Research on degradation of silk fibroin by combination of electron beam irradiation and hydrothermal processing

    International Nuclear Information System (INIS)

    Silk fibers and silk proteins have been demonstrated to be useful to apply in the textile industry, biomedical, cosmetics, pharmaceuticals. In this study, the effects of electron beam (EB) irradiation combined with hydrothermal processing to the solubility of silk fibroin and generation of soluble silk protein were investigated. The solubility of unirradiated and irradiated fibroin samples were greater than 80 % when hydrothermal degradation was performed in the sodium hydroxide solution at an appropriate concentration of 0.05 M. However, the solubility of irradiated fibroin was greater than that of unirradiated sample. The soluble silk protein content increased from 0.462 to 0.653 mg protein/mg silk fibroin when irradiation doses increased from 0 to 200 kGy, respectively. The molecular weight of protein was determined by SDS-PAGE method. The characteristics of silk protein were confirmed by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). (author)

  4. Degradation of catechol by ionizing radiation, ozone and the combined process ozone-electron-beam

    International Nuclear Information System (INIS)

    The influence of oxygen on the radiation-induced degradation of catechol (5x10-4 mol dm-3, 55 mg dm-3) in distilled water was studied by gamma-radiolysis in the presence of air (A) and using air saturation (AS) during irradiation. Under AS conditions a complete decomposition of catechol as well as of the trihydroxybenzene products was obtained by a dose of 6 kGy, without air saturation all phenolic compounds were still present at 10 kGy. Using AS, at 12 kGy the total organic carbon (TOC) was reduced by 63%, without air saturation by 17.5%. Detoxification was only obtained in AS solutions. In the presence of the natural matrix of the local tap water no trihydroxybenzene products were formed and for total decomposition of catechol in AS solutions 9 kGy were required. The comparison of the effectiveness of an electron beam (EB), an ozone (O3) and a combined EB/O3 process showed, that by EB/O3 the extent of catechol degradation corresponded to the sum of the decay with EB and with ozone, whereas for the chemical oxygen demand and TOC reduction a synergistic effect was evident

  5. Determining DVH parameters for combined external beam and brachytherapy treatment: 3D biological dose adding for patients with cervical cancer

    NARCIS (Netherlands)

    J.B. van de Kamer; A.A.C. de Leeuw; M.A. Moerland; I.M. Jürgenliemk-Schulz

    2010-01-01

    Purpose: To compare two methods of DVH parameter determination for combined external beam and brachytherapy treatment of cervical cancer. Materials and methods: Clinical treatment plans from five patients were used in this study. We simulated two applications given with PDR (32 x 60 cGy per applicat

  6. Note: Determination of torsional spring constant of atomic force microscopy cantilevers: Combining normal spring constant and classical beam theory

    DEFF Research Database (Denmark)

    Álvarez-Asencio, R.; Thormann, Esben; Rutland, M.W.

    2013-01-01

    A technique has been developed for the calculation of torsional spring constants for AFM cantilevers based on the combination of the normal spring constant and plate/beam theory. It is easy to apply and allow the determination of torsional constants for stiff cantilevers where the thermal power...

  7. Renewal Strings for Cleaning Astronomical Databases

    CERN Document Server

    Storkey, Amos J; Williams, Christopher K I; Mann, Robert G

    2014-01-01

    Large astronomical databases obtained from sky surveys such as the SuperCOSMOS Sky Surveys (SSS) invariably suffer from a small number of spurious records coming from artefactual effects of the telescope, satellites and junk objects in orbit around earth and physical defects on the photographic plate or CCD. Though relatively small in number these spurious records present a significant problem in many situations where they can become a large proportion of the records potentially of interest to a given astronomer. In this paper we focus on the four most common causes of unwanted records in the SSS: satellite or aeroplane tracks, scratches fibres and other linear phenomena introduced to the plate, circular halos around bright stars due to internal reflections within the telescope and diffraction spikes near to bright stars. Accurate and robust techniques are needed for locating and flagging such spurious objects. We have developed renewal strings, a probabilistic technique combining the Hough transform, renewal...

  8. The CERES Astronomical Database

    CERN Document Server

    Xanthopoulos, E; Snellen, I; Dennett-Thorpe, J; Mack, K H

    1999-01-01

    The CERES Astronomical Archive was created initially in order to make the large amount of data that were collected from the two surveys, the Jodrell-VLA Astrometric Survey (JVAS) and the Cosmic Lens All-Sky Survey (CLASS), easily accessible to the partner members of the Consortium for European Research on Extragalactic Surveys (CERES) through the web. Here we describe the web based archive of the 15,000 flat spectrum radio sources. There is a wealth of information that one can access including downloading the raw and processed data for each of the sources. We also describe the search engines that were developed so that a) one can search through the archive for an object or a sample of objects by setting specific criteria and b) select new samples. Since new data are continually gathered on the same sources from follow up programs, an automatic update engine was created so that the new information and data can be added easily in the archive.

  9. Closing remarks: astronomical

    International Nuclear Information System (INIS)

    During the discussions we have covered many facets of the basic interactions between solar activity and the Earth's climate. Solar activity is not the only astronomical or astrophysical phenomenon to influence physical conditions in the biosphere. Over timescales an order of magnitude less, the location of the Solar System in the Galaxy may have influenced life on Earth. The Sun is a complex generator of radiation, particles and magnetic fields sent far into space. Even if the total radiation emitted is constant, the amount of radiation received by the Earth changes with time: this change is complex and involved with a redistribution of energy emitted at different solar latitudes than to a real change in solar luminosity. These changes in the Earth's illumination may be a function of the wavelength, and have various effects in different layers of the Earth's atmosphere. The Sun also emits particles of all energies. Some of them find their way through the magnetopause, giving rise to auroras, to magnetic storms, to ionospheric disturbances and the like. The possible climatological effects are yet obscure. To understand the solar terrestrial relations better, regular, routine observations from ground-based stations and from space of solar phenomena must be continued. The sensitivity of human life to small changes in climatic conditions is very large. A good knowledge of solar-physics is therefore important and relevant. (author)

  10. XEphem: Interactive Astronomical Ephemeris

    Science.gov (United States)

    Downey, Elwood Charles

    2011-12-01

    XEphem is a scientific-grade interactive astronomical ephemeris package for UNIX-like systems. Written in C, X11 and Motif, it is easily ported to systems. Among other things, XEphem: computes heliocentric, geocentric and topocentric information for all objects; has built-in support for all planets; the moons of Mars, Jupiter, Saturn, Uranus and Earth; central meridian longitude of Mars and Jupiter; Saturn's rings; and Jupiter's Great Red Spot; allows user-defined objects including stars, deepsky objects, asteroids, comets and Earth satellites; provides special efficient handling of large catalogs including Tycho, Hipparcos, GSC; displays data in configurable tabular formats in conjunction with several interactive graphical views; displays a night-at-a-glance 24 hour graphic showing when any selected objects are up; displays 3-D stereo Solar System views that are particularly well suited for visualizing comet trajectories; quickly finds all close pairs of objects in the sky; and sorts and prints all catalogs with very flexible criteria for creating custom observing lists. Its capabilities are listed more fully in the user manual introduction.

  11. Using commercial amateur astronomical spectrographs

    CERN Document Server

    Hopkins, Jeffrey L

    2014-01-01

    Amateur astronomers interested in learning more about astronomical spectroscopy now have the guide they need. It provides detailed information about how to get started inexpensively with low-resolution spectroscopy, and then how to move on to more advanced  high-resolution spectroscopy. Uniquely, the instructions concentrate very much on the practical aspects of using commercially-available spectroscopes, rather than simply explaining how spectroscopes work. The book includes a clear explanation of the laboratory theory behind astronomical spectrographs, and goes on to extensively cover the practical application of astronomical spectroscopy in detail. Four popular and reasonably-priced commercially available diffraction grating spectrographs are used as examples. The first is a low-resolution transmission diffraction grating, the Star Analyser spectrograph. The second is an inexpensive fiber optic coupled bench spectrograph that can be used to learn more about spectroscopy. The third is a newcomer, the ALPY ...

  12. Islamic Astronomical Instruments and Observatories

    Science.gov (United States)

    Heidarzadeh, Tofigh

    This chapter is a brief survey of astronomical instruments being used and developed in Islamic territories from the eighth to the fifteenth centuries as well as a concise account of major observatories and observational programs in this period.

  13. Experimental Investigation on Reinforced Ultra-High-Performance Fiber-Reinforced Concrete Composite Beams Subjected to Combined Bending and Shear

    OpenAIRE

    Noshiravani, Talayeh; Bruehwiler, Eugen

    2013-01-01

    An experimental study on a series of composite beams combining a 250 mm (9.84 in.) deep reinforced concrete (RC) element and a 50 mm (1.97 in.) thick reinforced ultra-high-performance fiber-reinforced concrete (R-UHPFRC) element is presented. The specimens are tested in a cantilever-beam setup with the R-UHPFRC element acting as an additional tensile reinforcement. The test parameters include the span length and the ratio and type of the steel reinforcing bars, including stirrups. Most of the...

  14. Shear Lag in a Plywood Sheet-stringer Combination Used for the Chord Member of a Box Beam

    Science.gov (United States)

    Borsari, Palamede; Yu, Ai-Ting

    1948-01-01

    Theoretical and experimental investigations were made of the distribution of strains in a plywood sheet-stringer combination used as the chord member of a box beam acted upon by bending loads. The theoretical solution was obtained with the help of the principle of minimum potential energy and certain simplifying assumptions. Strain measurements were made on a build-up box beam by means of electrical-resistance strain gages connected with strain indicators. A very satisfactory agreement between the theoretical and experimental strains was obtained.

  15. Analytical theory of flexural behavior of concrete beam reinforced with textile-combined steel

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Textile-reinforced concrete (TRC) is a new high performance cementitious composite material,which not only has superior corrosion resistance but also can effectively limit the development of concrete cracks and make the crack width and spacing of concrete become smaller.However,due to the brittle feature of fiber materials,the TRC structural member has no distinct failure symptom when it arrives at its ultimate load.At the same time,ordinary reinforced concrete (RC) elements have large dead weight and can not efficiently restrict the expansion of the main crack of structures because of the restriction of their special cover thickness.In order to overcome the disadvantages of both the TRC and the RC,a new architecture reinforced with textile-combined steel is proposed in this study,making full use of the advantages of the above two structures.The cover concrete at the tension zone of an RC element is partially replaced with TRC and thus the steel reinforcements replaced with textiles are subtracted.Compared with the old one,the new structure has less dead weight and has the merits of service safety and good durability.The flexural development process of the proper beam with this new structure is investigated in this paper and based on the plane section assumption,analytical equations are derived by using nonlinear analysis theory,including the load-carrying capacity at different stages and moment-curvature relationship and mid-span deflection during the entire loading process.Comparison between the calculated and the experimental results reveals satisfactory agreement and thus verifies the feasibility of the equations.

  16. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research.

    Science.gov (United States)

    Lampert, M; Anda, G; Czopf, A; Erdei, G; Guszejnov, D; Kovácsik, Á; Pokol, G I; Réfy, D; Nam, Y U; Zoletnik, S

    2015-07-01

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera's measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties. PMID:26233377

  17. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research

    International Nuclear Information System (INIS)

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties

  18. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, M. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); BME NTI, Budapest (Hungary); Anda, G.; Réfy, D.; Zoletnik, S. [Wigner RCP, Euratom Association-HAS, Budapest (Hungary); Czopf, A.; Erdei, G. [Department of Atomic Physics, BME IOP, Budapest (Hungary); Guszejnov, D.; Kovácsik, Á.; Pokol, G. I. [BME NTI, Budapest (Hungary); Nam, Y. U. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-07-15

    A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera’s measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties.

  19. Fabrication of particle-free thin films by laser ablation combined with an electron beam

    International Nuclear Information System (INIS)

    Particle-free silicon and nickel thin films were successfully fabricated by laser-ablating a melted section of their target surface, which gives a high evaporation pressure at the melting point. The influence of direct evaporation from a melted target was reduced negligibly by melting the target only locally with a focused electron beam (e-beam) and increasing the laser frequency. The silicon films fabricated by the present method, pulse laser deposition of a partially molten target, were able to firmly adhere to the substrates and withstood steel needle scratching, unlike e-beam-evaporated films

  20. Astronomy Legacy Project - Pisgah Astronomical Research Institute

    Science.gov (United States)

    Barker, Thurburn; Castelaz, Michael W.; Rottler, Lee; Cline, J. Donald

    2016-01-01

    Pisgah Astronomical Research Institute (PARI) is a not-for-profit public foundation in North Carolina dedicated to providing hands-on educational and research opportunities for a broad cross-section of users in science, technology, engineering and math (STEM) disciplines. In November 2007 a Workshop on a National Plan for Preserving Astronomical Photographic Data (2009ASPC,410,33O, Osborn, W. & Robbins, L) was held at PARI. The result was the establishment of the Astronomical Photographic Data Archive (APDA) at PARI. In late 2013 PARI began ALP (Astronomy Legacy Project). ALP's purpose is to digitize an extensive set of twentieth century photographic astronomical data housed in APDA. Because of the wide range of types of plates, plate dimensions and emulsions found among the 40+ collections, plate digitization will require a versatile set of scanners and digitizing instruments. Internet crowdfunding was used to assist in the purchase of additional digitization equipment that were described at AstroPlate2014 Plate Preservation Workshop (www.astroplate.cz) held in Prague, CZ, March, 2014. Equipment purchased included an Epson Expression 11000XL scanner and two Nikon D800E cameras. These digital instruments will compliment a STScI GAMMA scanner now located in APDA. GAMMA will be adapted to use an electroluminescence light source and a digital camera with a telecentric lens to achieve high-speed high-resolution scanning. The 1μm precision XY stage of GAMMA will allow very precise positioning of the plate stage. Multiple overlapping CCD images of small sections of each plate, tiles, will be combined using a photo-mosaic process similar to one used in Harvard's DASCH project. Implementation of a software pipeline for the creation of a SQL database containing plate images and metadata will be based upon APPLAUSE as described by Tuvikene at AstroPlate2014 (www.astroplate.cz/programs/).

  1. Photon reconstruction in the ATLAS Inner Detector and Liquid Argon Barrel Calorimeter at the 2004 Combined Test Beam

    International Nuclear Information System (INIS)

    The reconstruction of photons in the ATLAS detector is studied with data taken during the 2004 Combined Test Beam, where a full slice of the ATLAS detector was exposed to beams of particles of known energy at the CERN SPS. The results presented show significant differences in the longitudinal development of the electromagnetic shower between converted and unconverted photons as well as in the total measured energy. The potential to use the reconstructed converted photons as a means to precisely map the material of the tracker in front of the electromagnetic calorimeter is also considered. All results obtained are compared with a detailed Monte-Carlo simulation of the test-beam setup which is based on the same simulation and reconstruction tools as those used for the ATLAS detector itself.

  2. Photon reconstruction in the ATLAS Inner Detector and Liquid Argon Barrel Calorimeter at the 2004 Combined Test Beam

    CERN Document Server

    Abat, E; Addy, T N; Adragna, P; Aharrouche, M; Ahmad, A; Akesson, T.P A; Aleksa, M; Alexa, C; Anderson, K; Andreazza, A; Anghinolfi, F; Antonaki, A; Arabidze, G; Arik, E; Atkinson, T; Baines, J; Baker, O K; Banfi, D; Baron, S; Barr, A J; Beccherle, R; Beck, H P; Belhorma, B; Bell, P J; Benchekroun, D; Benjamin, D P; Benslama, K; Bergeaas Kuutmann, E; Bernabeu, J; Bertelsen, H; Binet, S; Biscarat, C; Boldea, V; Bondarenko, V G; Boonekamp, M; Bosman, M; Bourdarios, C; Broklova, Z; Burckhart-Chromek, D; Bychkov, V; Callahan, J; Calvet, D; Canneri, M; Capeans Garrido, M; Caprini, M; Cardiel Sas, L; Carli, T; Carminati, L; Carvalho, J; Cascella, M; Castillo, M V; Catinaccio, A; Cauz, D; Cavalli, D; Cavalli-Sforza, M; Cavasinni, V; Cetin, S A; Chen, H; Cherkaoui, R; Chevalier, L; Chevallier, F; Chouridou, S; Ciobotaru, M; Citterio, M; Clark, A; Cleland, B; Cobal, M; Cogneras, E; Conde Muino, P; Consonni, M; Constantinescu, S; Cornelissen, T; Correard, S; Corso-Radu, A; Costa, G; Costa, M J; Costanzo, D; Cuneo, S; Cwetanski, P; Da Silva, D; Dam, M; Dameri, M; Danielsson, H O; Dannheim, D; Darbo, G; Davidek, T; De, K; Defay, P O; Dekhissi, B; Del Peso, J; Del Prete, T; Delmastro, M; Derue, F; Di Ciaccio, L; Di Girolamo, B; Dita, S; Dittus, F; Djama, F; Djobava, T; Dobos, D; Dobson, M; Dolgoshein, B A; Dotti, A; Drake, G; Drasal, Z; Dressnandt, N; Driouchi, C; Drohan, J; Ebenstein, W L; Eerola, P; Efthymiopoulos, I; Egorov, K; Eifert, T F; Einsweiler, K; El Kacimi, M; Elsing, M; Emelyanov, D; Escobar, C; Etienvre, A I; Fabich, A; Facius, K; Idrissi Fakhr-Eddine, A; Fanti, M; Farbin, A; Farthouat, P; Fassouliotis, D; Fayard, L; Febbraro, R; Fedin, O L; Fenyuk, A; Fergusson, D; Ferrari, P; Ferrari, R; Ferreira, B C; Ferrer, A; Ferrere, D; Filippini, G; Flick, T; Fournier, D; Francavilla, P; Francis, D; Froeschl, R; Froidevaux, D; Fullana, E; Gadomski, S; Gagliardi, G; Gagnon, P; Gallas, M; Gallop, B J; Gameiro, S; Gan, K K; Garcia, R; Garcia, C; Gavrilenko, I L; Gemme, C; Gerlach, P; Ghodbane, N; Giakoumopoulou, V; Giangiobbe, V; Giokaris, N; Glonti, G; Gottfert, T.; Golling, T; Gollub, N; Gomes, A; Gomez, M D; Gonzalez-Sevilla, S; Goodrick, M J; Gorfine, G; Gorini, B; Goujdami, D; Grahn, K J; Grenier, P; Grigalashvili, N; Grishkevich, Y; Grosse-Knetter, J; Gruwe, M; Guicheney, C; Gupta, A; Haeberli, C; Hartel, R.; Hajduk, Z; Hakobyan, H; Hance, M; Hansen, J D; Hansen, P H; Hara, K; Harvey, A., Jr; Hawkings, R J; Heinemann, F.E W; Henriques Correia, A; Henss, T; Hervas, L; Higon, E; Hill, J C; Hoffman, J; Hostachy, J Y; Hruska, I; Hubaut, F; Huegging, F; Hulsbergen, W; Hurwitz, M; Iconomidou-Fayard, L; Jansen, E; Jen-La Plante, I; Johansson, P.D C; Jon-And, K; Joos, M; Jorgensen, S; Joseph, J; Kaczmarska, A; Kado, M; Karyukhin, A; Kataoka, M; Kayumov, F; Kazarov, A; Keener, P T; Kekelidze, G D; Kerschen, N; Kersten, S; Khomich, A; Khoriauli, G; Khramov, E; Khristachev, A; Khubua, J; Kittelmann, T H; Klingenberg, R; Klinkby, E B; Kodys, P; Koffas, T; Kolos, S; Konovalov, S P; Konstantinidis, N; Kopikov, S; Korolkov, I; Kostyukhin, V; Kovalenko, S; Kowalski, T Z; Kruger, K.; Kramarenko, V; Kudin, L G; Kulchitsky, Y; Lacasta, C; Lafaye, R; Laforge, B; Lampl, W; Lanni, F; Laplace, S; Lari, T; Le Bihan, A C; Lechowski, M; Ledroit-Guillon, F; Lehmann, G; Leitner, R; Lelas, D; Lester, C G; Liang, Z; Lichard, P; Liebig, W; Lipniacka, A; Lokajicek, M; Louchard, L; Loureiro, K F; Lucotte, A; Luehring, F; Lund-Jensen, B; Lundberg, B; Ma, H; Mackeprang, R; Maio, A; Maleev, V P; Malek, F; Mandelli, L; Maneira, J; Mangin-Brinet, M; Manousakis, A; Mapelli, L; Marques, C; Marti i Garcia, S; Martin, F; Mathes, M; Mazzanti, M; McFarlane, K W; McPherson, R; Mchedlidze, G; Mehlhase, S; Meirosu, C; Meng, Z; Meroni, C; Mialkovski, V; Mikulec, B; Milstead, D; Minashvili, I; Mindur, B; Mitsou, V A; Moed, S; Monnier, E; Moorhead, G; Morettini, P; Morozov, S V; Mosidze, M; Mouraviev, S V; Moyse, E.W J; Munar, A; Myagkov, A; Nadtochi, A V; Nakamura, K; Nechaeva, P; Negri, A; Nemecek, S; Nessi, M; Nesterov, S Y; Newcomer, F M; Nikitine, I; Nikolaev, K; Nikolic-Audit, I; Ogren, H; Oh, S H; Oleshko, S B; Olszowska, J; Onofre, A; Padilla Aranda, C; Paganis, S; Pallin, D; Pantea, D; Paolone, V; Parodi, F; Parsons, J; Parzhitski, S; Pasqualucci, E; Passmore, S M; Pater, J; Patrichev, S; Peez, M; Perez Reale, V; Perini, L; Peshekhonov, V D; Petersen, J; Petersen, T C; Petti, R; Phillips, P W; Pilcher, J; Pina, J; Pinto, B; Podlyski, F; Poggioli, L; Poppleton, A; Poveda, J; Pralavorio, P; Pribyl, L; Price, M J; Prieur, D; Puigdengoles, C; Puzo, P; Ragusa, F; Rajagopalan, S; Reeves, K; Reisinger, I; Rembser, C; Bruckman de Renstrom, P.A.; Reznicek, P; Ridel, M; Risso, P; Riu, I; Robinson, D; Roda, C; Roe, S; Rohne, O.; Romaniouk, A; Rousseau, D; Rozanov, A; Ruiz, A; Rusakovich, N; Rust, D; Ryabov, Y F; Ryjov, V; Salto, O; Salvachua, B; Salzburger, A; Sandaker, H; Santamarina Rios, C.Santamarina; Santi, L; Santoni, C; Saraiva, J G; Sarri, F; Sauvage, G; Says, L P; Schaefer, M; Schegelsky, V A; Schiavi, C; Schieck, J; Schlager, G; Schlereth, J; Schmitt, C; Schultes, J; Schwemling, P; Schwindling, J; Seixas, J M; Seliverstov, D M; Serin, L; Sfyrla, A; Shalanda, N; Shaw, C; Shin, T; Shmeleva, A; Silva, J; Simion, S; Simonyan, M; Sloper, J E; Smirnov, S.Yu; Smirnova, L; Solans, C; Solodkov, A; Solovianov, O; Soloviev, I; Sosnovtsev, V V; Spano, F; Speckmayer, P; Stancu, S; Stanek, R; Starchenko, E; Straessner, A; Suchkov, S I; Suk, M; Szczygiel, R; Tarrade, F; Tartarelli, F; Tas, P; Tayalati, Y; Tegenfeldt, F; Teuscher, R; Thioye, M; Tikhomirov, V O; Timmermans, C.J.W P; Tisserant, S; Toczek, B; Tremblet, L; Troncon, C; Tsiareshka, P; Tyndel, M; Karagoz Unel, M.; Unal, G; Unel, G; Usai, G; Van Berg, R; Valero, A; Valkar, S; Valls, J A; Vandelli, W; Vannucci, F; Vartapetian, A; Vassilakopoulos, V I; Vasilyeva, L; Vazeille, F; Vernocchi, F; Vetter-Cole, Y; Vichou, I; Vinogradov, V; Virzi, J; Vivarelli, I; de Vivie, J B; Volpi, M; Vu Anh, T; Wang, C; Warren, M; Weber, J; Weber, M; Weidberg, A R; Weingarten, J; Wells, P S; Werner, P; Wheeler, S; Wiesmann, M; Wilkens, H; Williams, H H; Wingerter-Seez, I; Yasu, Y; Zaitsev, A; Zenin, A; Zenis, T; Zenonos, Z; Zhang, H; Zhelezko, A; Zhou, N

    2011-01-01

    The reconstruction of photons in the ATLAS detector is studied with data taken during the 2004 Combined Test Beam, where a full slice of the ATLAS detector was exposed to beams of particles of known energy at the CERN SPS. The results presented show significant differences in the longitudinal development of the electromagnetic shower between converted and unconverted photons as well as in the total measured energy. The potential to use the reconstructed converted photons as a means to precisely map the material of the tracker in front of the electromagnetic calorimeter is also considered. All results obtained are compared with a detailed Monte-Carlo simulation of the test-beam setup which is based on the same simulation and reconstruction tools as those used for the ATLAS detector itself.

  3. The New Amateur Astronomer

    Science.gov (United States)

    Mobberley, Martin

    Amateur astronomy has changed beyond recognition in less than two decades. The reason is, of course, technology. Affordable high-quality telescopes, computer-controlled 'go to' mountings, autoguiders, CCD cameras, video, and (as always) computers and the Internet, are just a few of the advances that have revolutionized astronomy for the twenty-first century. Martin Mobberley first looks at the basics before going into an in-depth study of what’s available commercially. He then moves on to the revolutionary possibilities that are open to amateurs, from imaging, through spectroscopy and photometry, to patrolling for near-earth objects - the search for comets and asteroids that may come close to, or even hit, the earth. The New Amateur Astronomer is a road map of the new astronomy, equally suitable for newcomers who want an introduction, or old hands who need to keep abreast of innovations. From the reviews: "This is one of several dozen books in Patrick Moore's "Practical Astronomy" series. Amid this large family, Mobberley finds his niche: the beginning high-tech amateur. The book's first half discusses equipment: computer-driven telescopes, CCD cameras, imaging processing software, etc. This market is changing every bit as rapidly as the computer world, so these details will be current for only a year or two. The rest of the book offers an overview of scientific projects that serious amateurs are carrying out these days. Throughout, basic formulas and technical terms are provided as needed, without formal derivations. An appendix with useful references and Web sites is also included. Readers will need more than this book if they are considering a plunge into high-tech amateur astronomy, but it certainly will whet their appetites. Mobberley's most valuable advice will save the book's owner many times its cover price: buy a quality telescope from a reputable dealer and install it in a simple shelter so it can be used with as little set-up time as possible. A poor

  4. Enthusiastic Little Astronomers

    Science.gov (United States)

    Novak, Ines

    2016-04-01

    Younger primary school students often show great interest in the vast Universe hiding behind the starry night's sky, but don't have a way of learning about it and exploring it in regular classes. Some of them would search children's books, Internet or encyclopedias for information or facts they are interested in, but there are those whose hunger for knowledge would go unfulfilled. Such students were the real initiators of our extracurricular activity called Little Astronomers. With great enthusiasm they would name everything that interests them about the Universe that we live in and I would provide the information in a fun and interactive yet acceptable way for their level of understanding. In our class we learn about Earth and its place in the Solar System, we learn about the planets and other objects of our Solar System and about the Sun itself. We also explore the night sky using programs such as Stellarium, learning to recognize constellations and name them. Most of our activities are done using a PowerPoint presentation, YouTube videos, and Internet simulations followed by some practical work the students do themselves. Because of the lack of available materials and funds, most of materials are hand made by the teacher leading the class. We also use the school's galileoscope as often as possible. Every year the students are given the opportunity to go to an observatory in a town 90 km away so that they could gaze at the sky through the real telescope for the first time. Our goal is to start stepping into the world of astronomy by exploring the secrets of the Universe and understanding the process of rotation and revolution of our planet and its effects on our everyday lives and also to become more aware of our own role in our part of the Universe. The hunger for knowledge and enthusiasm these students have is contagious. They are becoming more aware of their surroundings and also understanding their place in the Universe that helps them remain humble and helps

  5. Choosing and using astronomical eyepieces

    CERN Document Server

    Paolini, William

    2013-01-01

    This valuable reference fills a number of needs in the field of astronomical eyepieces, including that of a buyer's guide, observer's field guide and technical desk reference. It documents the past market for eyepieces and its evolution right up to the present day. In addition to appealing to practical astronomers - and potentially saving them money - it is useful both as a historical reference and as a detailed review of the current market place for this bustling astronomical consumer product. What distinguishes this book from other publications on astronomy is the involvement of observers from all aspects of the astronomical community, and also the major manufacturers of equipment. It not only catalogs the technical aspects of the many modern eyepieces but also documents amateur observer reactions and impressions of their utility over the years, using many different eyepieces. Eyepieces are the most talked-about accessories and collectible items available to the amateur astronomer. No other item of equi...

  6. In Brief: Astronomer honored with a mineral

    Science.gov (United States)

    Showstack, Randy

    2008-06-01

    ``I have always been very intrigued by minerals, so it is great to be one,'' commented NASA Stardust mission principal investigator and University of Washington astronomer Donald Brownlee, AGU member, after learning the International Mineralogical Association had named a new mineral in his honor. Brownleeite, a combination of manganese and silicon, is the first mineral discovered in a particle from a comet. The mineral was found inside a particle collected by a high-altitude NASA aircraft from a dust stream that entered Earth's atmosphere in 2003. A team led by NASA scientist Keiko Nakamura-Messenger found the particle and had requested that it be named for Brownlee.

  7. Combined treatment of localized prostata cancer with HDR-Iridium 192 remote brachytherapy and external beam irradiation

    International Nuclear Information System (INIS)

    Background: The localized prostate cancer can be treated curatively by radiation therapy. The combined treatment of external beam irradiation and HDR-Iridium 192 remote brachytherapy allows higher radiation doses within the tumor without increasing radiation sequelae. Patients and Methods: Patients of our clinic have been treated with this combined procedure since 1991. Between 1991 and 1994 15 patients received 2x9 Gy of high-dose-rate brachytherapy, followed by 36 Gy external beam irradiation (group A). Because of the frequent local failures in group A, the reference dose of external beam irradiation was increased to 50.4 Gy after brachytherapy between 1994 and 1996. Results: Seven of 15 patients (47%) in group A developed a local recurrence after a median of 17 (13 to 30) months. In group B (20 patients) local failure occurred in 3 patients (15%) after 11, 16 and 32 months. Conclusion: The combined radiation therapy of localized prostate cancer cannot substitute radical prostatectomy completely, but it is a promising alternative in the curative treatment in selected patients. (orig.)

  8. Treatment of keloid in upper limb by combined surgical excision and immediate postoperative electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Kenichi; Yoshida, Jun; Heshiki, Takaya; Ishikura, Naotaka; Kawakami, Shigehiko [Kanazawa Medical Univ., Uchinada, Ishikawa (Japan)

    2002-02-01

    A scar in the upper extremities sometimes leads to onset of keloid, whose treatment is difficult and many treatment methods have been tried. Recently our hospital has performed electron beam radiation for treatment of keloid. In this report, we describe our examination on patients with keloid in the upper extremities who visited our hospital and underwent electron beam irradiation in these past 7 years. The patients were 9 males and 15 females, age between 9 and 84 (average age 26.6 years). Treatments included the following: Total ablation of keloid plus electron beam radiation, electron beam radiation alone, localized administration of triamcinolone. Treatment evaluation and presence or absence of pigmentation was examined. Electron beam radiation was performed with a total of 25 Gy for consecutive 5 days by 5 Gy electron beam since 1 week after keloid ablation with sufficient informed consent. Onset site of 24 patients with keloid in the upper extremities was the shoulder in 12 patients, the upper arm in 11, and the elbow in one patient. Development cause was BCG inoculation in 8 patients, wound associated with surgery in 6, unknown cause in 6, and others in 4 patients. The number of patients who were followed-up after treatment was 16 for each examination respectively, and mean followed-up period was 2 years and 10 months. Postoperative evaluation for ablation plus electron beam was good in 1 patient and fair in 6, that for electron beam radiation alone was good in 1, fair in 2, and unknown in 2, and that for triamcinolone was fair in 2, poor in 4, and unknown in 1 patient. Postoperative pigmentation was observed in all the patients immediately after radiation, and at the time of final follow-up, in 6 (33%) out of 9 patients confirmed. Ablation plus electron beam irradiation for keloid in the upper extremities was effective. However, this treatment cannot avoid a possibility of cancerogenesis. Thus, sufficient explanation and consent may be essential after full

  9. VISION: A Six-Telescope Fiber-Fed Visible Light Beam Combiner for the Navy Precision Optical Interferometer

    CERN Document Server

    Garcia, Eugenio V; van Belle, Gerard; Monnier, John D; Stassun, Keivan G; Ghasempour, Askari; Clark, James H; Zavala, R T; Benson, James A; Hutter, Donald J; Schmitt, Henrique R; Baines, Ellyn K; Jorgensen, Anders M; Strosahl, Susan G; Sanborn, Jason; Zawicki, Stephen J; Sakosky, Michael F; Swihart, Samuel

    2016-01-01

    Visible-light long baseline interferometry holds the promise of advancing a number of important applications in fundamental astronomy, including the direct measurement of the angular diameters and oblateness of stars, and the direct measurement of the orbits of binary and multiple star systems. To advance, the field of visible-light interferometry requires development of instruments capable of combining light from 15 baselines (6 telescopes) simultaneously. The Visible Imaging System for Interferometric Observations at NPOI (VISION) is a new visible light beam combiner for the Navy Precision Optical Interferometer (NPOI) that uses single-mode fibers to coherently combine light from up to six telescopes simultaneously with an image-plane combination scheme. It features a photometric camera for calibrations and spatial filtering from single-mode fibers with two Andor Ixon electron multiplying CCDs. This paper presents the VISION system, results of laboratory tests, and results of commissioning on-sky observatio...

  10. Astronomical Image and Data Analysis

    CERN Document Server

    Starck, J.-L

    2006-01-01

    With information and scale as central themes, this comprehensive survey explains how to handle real problems in astronomical data analysis using a modern arsenal of powerful techniques. It treats those innovative methods of image, signal, and data processing that are proving to be both effective and widely relevant. The authors are leaders in this rapidly developing field and draw upon decades of experience. They have been playing leading roles in international projects such as the Virtual Observatory and the Grid. The book addresses not only students and professional astronomers and astrophysicists, but also serious amateur astronomers and specialists in earth observation, medical imaging, and data mining. The coverage includes chapters or appendices on: detection and filtering; image compression; multichannel, multiscale, and catalog data analytical methods; wavelets transforms, Picard iteration, and software tools. This second edition of Starck and Murtagh's highly appreciated reference again deals with to...

  11. 古建筑木结构叠合梁与组合梁弯曲受力研究%Bending analysis on composite beam and combination beam of Chinese ancient wooden buildings

    Institute of Scientific and Technical Information of China (English)

    周乾; 闫维明

    2012-01-01

    采用力学分析方法,研究了古建筑木结构叠合梁与组合梁弯曲受力问题。以工程中常见的矩形木梁为例,讨论了如下3个问题:1)单梁开裂形成叠合梁后的弯曲受力性能;2)叠合梁与组合梁弯曲受力性能的区别;3)古建筑叠合梁"工字形"抗弯截面的合理性。结果表明:1)单梁开裂后形成叠合梁,将导致截面弯应力峰值大幅度增加;2)单梁加固采用组合梁做法比叠合梁做法更能节约材料且效果更好,且采用钢材加固木梁比木材加固木梁所需截面尺寸小;3)古建筑叠合梁"工字形"截面与相应等高度矩形截面相比,受弯承载力变化不大,具有合理性。%By mechanical analysis methods,internal forces of composite beam and combination beam of Chinese ancient wooden buildings under bending loads were studied.A typical rectangular beam was taken as an example to discuss the following problems: 1) variation of bending stress distribution of the beam after it cracked completely to form a composite beam;2) when the beam was considered to be strengthened by composite beam or combination beam,the difference of bending performance between them;3) rationality of "I-section" type of composite beam or combination beam of Chinese ancient buildings.Results show that:1) after a single beam cracks completely to form a composite beam,its peak bending stress value increases greatly,which may make itself destroyed;2) when a single beam is strengthened by an additional beam,the combination beam is better than the composite beam,and steel is better than wood so far as strengthening material is concerned;3) bending capability of "I-section" type of composite beam or combination beam of Chinese ancient buildings changes little compared to that of rectangular section type,which reflects its rationality.

  12. Combined total body X-ray irradiation and total skin electron beam radiotherapy with an improved technique for mycosis fungoides

    International Nuclear Information System (INIS)

    Twelve consecutive patients with advanced stage mycosis fungoides (MF) were treated with combined total body X ray irradiation (TBI) and total skin electron beam radiotherapy (EBRT). Six had generalized plaque disease and dermatopathic nodes, three had tumor stage disease and node biopsy positive for mycosis fungoides, and three had erythroderma/Sezary syndrome. The treatment regimen consisted of split course total body X ray irradiation, given in twice weekly 15 cGy fractions to 75 cGy, then total skin electron beam radiation therapy given in once weekly 400 cGy fractions to a total dose of 2400 cGy. Underdosed areas and areas of greatest initial involvement were boosted 400 cGy twice weekly for an additional 1200 cGy. This was followed by a second course of total body X ray irradiation, to a total dose of 150 cGy. The total skin electron beam radiotherapy technique is a modification of an established six position EBRT technique for mycosis fungoides. Measurements to characterize the beam with and without a lexan scattering plate, demonstrated that the combination of no-plate beams produced better dose uniformity with a much higher dose rate. This improved technique is particularly advantageous for elderly and/or frail patients. Nine (75%) of the 12 patients achieved complete response (CR). The other three had significant improvement with greater than 80% clearing of their disease and resolution of symptoms. All six patients with generalized plaque disease achieved complete response and remained free of disease from 2 to 16 months. Two of three node positive patients also achieved complete response; one, with massive biopsy-documented mycosis fungoides nodal disease and deep open tumors, remained relapse-free over 2 years. Only one of the three patients with erythroderma/Sezary syndrome achieved a complete response, which was short lived

  13. Choosing and using astronomical filters

    CERN Document Server

    Griffiths, Martin

    2014-01-01

    As a casual read through any of the major amateur astronomical magazines will demonstrate, there are filters available for all aspects of optical astronomy. This book provides a ready resource on the use of the following filters, among others, for observational astronomy or for imaging: Light pollution filters Planetary filters Solar filters Neutral density filters for Moon observation Deep-sky filters, for such objects as galaxies, nebulae and more Deep-sky objects can be imaged in much greater detail than was possible many years ago. Amateur astronomers can take

  14. Two-color above threshold ionization of atoms and ions in XUV Bessel beams and combined with intense laser light

    CERN Document Server

    Seipt, D; Surzhykov, A; Fritzsche, S

    2016-01-01

    The two-color above-threshold ionization (ATI) of atoms and ions is investigated for a vortex Bessel beam in the presence of a strong near-infrared (NIR) light field. While the photoionization is caused by the photons from the weak but extreme ultra-violet (XUV) vortex Bessel beam, the energy and angular distribution of the photoelectrons and their sideband structure are affected by the plane-wave NIR field. We here explore the energy spectra and angular emission of the photoelectrons in such two-color fields as a function of the size and location of the target (atoms) with regard to the beam axis. In addition, analogue to the circular dichroism in typical two-color ATI experiments with circularly polarized light, we define and discuss seven different dichroism signals for such vortex Bessel beams that arise from the various combinations of the orbital and spin angular momenta of the two light fields. For localized targets, it is found that these dichroism signals strongly depend on the size and position of t...

  15. Study on reinforced concrete beams strengthened using shape memory alloy wires in combination with carbon-fiber-reinforced polymer plates

    Science.gov (United States)

    Li, Hui; Liu, Zhi-qiang; Ou, Jin-ping

    2007-12-01

    It has been proven that carbon-fiber-reinforced polymer (CFRP) sheets or plates are capable of improving the strength of reinforced concrete (RC) structures. However, residual deformation of RC structures in service reduces the effect of CFRP strengthening. SMA can be applied to potentially decrease residual deformation and even close concrete cracks because of its recovery forces imposed on the concrete when heated. Therefore, a method of a RC structure strengthened by CFRP plates in combination with SMA wires is proposed in this paper. The strengthening effect of this method is investigated through experiments and numerical study based on the nonlinear finite element software ABAQUS in simple RC beams. Parametric analysis and assessment of damage by defining a damage index are carried out. The results indicate that recovery forces of SMA wires can decrease deflections and even close cracks in the concrete. The recovery rate of deflection of the beam increases with increasing the ratio of SMA wires. The specimen strengthened with CFRP plates has a relatively large stiffness and smaller damage index value when the residual deformation of the beam is first reduced by activation of the SMA wires. The effectiveness of this strengthening method for RC beams is verified by experimental and numerical results.

  16. Astronomical Limiting Magnitude at Langkawi Observatory

    Science.gov (United States)

    Zainuddin, Mohd. Zambri; Loon, Chin Wei; Harun, Saedah

    2010-07-01

    Astronomical limiting magnitude is an indicator for astronomer to conduct astronomical measurement at a particular site. It gives an idea to astronomer of that site what magnitude of celestial object can be measured. Langkawi National Observatory (LNO) is situated at Bukit Malut with latitude 6°18' 25'' North and longitude 99°46' 52'' East in Langkawi Island. Sky brightness measurement has been performed at this site using the standard astronomical technique. The value of the limiting magnitude measured is V = 18.6+/-1.0 magnitude. This will indicate that astronomical measurement at Langkawi observatory can only be done for celestial objects having magnitude less than V = 18.6 magnitudes.

  17. Relativistic astronomical time scales, relativistic scaling of astronomical constants, and the system of astronomical units

    CERN Document Server

    Klioner, S A

    2005-01-01

    The paper is devoted to a detailed explanation of relativistic scaling of astronomical quantities induced by times scales \\TDB and \\TT. It is argued that scaled time scales, scaled spatial coordinates and scaled masses should be considered as distinct quantities which themselves can be expressed in any units (rather then numerical values expressed in some non-SI units ("TDB units" and "TT units") as can be sometimes found in the literature). The system of astronomical units in the relativistic framework is discussed. The whole freedom in the definitions of the systems of astronomical units for TCB and TDB is demonstrated. A number of possible ways to freeze the freedom are shown and discussed. It is argued that in the near future one should probably think about converting AU into a defined quantity (by fixing its value in SI meters).

  18. An Astronomical Data Analyzing Monitor

    Science.gov (United States)

    Teuber, D.

    ThP need for exchange of programmes and data between astronomical facilities is generally recognized, but practicable concepts concerning its realization are rare. Standardization of data formats through FITS is widely accepted; for (interactive) programs, however, identical hardware configurations seem to be the favoured solution. As an alternative, a software approach to the problem is presented.

  19. Narrow polymer fibers obtained as a combination of photopolymerization and non-diffracting beams

    Czech Academy of Sciences Publication Activity Database

    Ježek, Jan; Čižmár, Tomáš; Zemánek, Pavel

    Bellingham: SPIE, 2006, 63262H:1-8. ISBN 0-8194-6405-8. ISSN 0277-786X. [Optical Trapping and Optical Micromanipulation III. San Diego (US), 13.08.2006-17.08.2006] R&D Projects: GA AV ČR KJB2065404; GA MŠk(CZ) LC06007 Institutional research plan: CEZ:AV0Z20650511 Keywords : fiber design * Bessel beams * photopolymerization Subject RIV: BH - Optics, Masers, Lasers

  20. A layer correlation technique for pion energy calibration at the 2004 ATLAS Combined Beam Test

    OpenAIRE

    Abat, E.; Abdallah, J. M.; Addy, T. N.; Adragna, P.; Aharrouche, M.; Ahmad, A; Akesson, T. P. A.; Aleksa, M.; Alexa, C; Anderson, K.; Andreazza, A.; Anghinolfi, F.; Antonaki, A.; Arabidze, G.; Arik, E.

    2016-01-01

    A new method for calibrating the hadron response of a segmented calorimeter is developed and successfully applied to beam test data. It is based on a principal component analysis of energy deposits in the calorimeter layers, exploiting longitudinal shower development information to improve the measured energy resolution. Corrections for invisible hadronic energy and energy lost in dead material in front of and between the calorimeters of the ATLAS experiment were calculated with simulated Gea...

  1. Combined modulated electron and photon beams planned by a Monte-Carlo-based optimization procedure for accelerated partial breast irradiation

    Science.gov (United States)

    Atriana Palma, Bianey; Ureba Sánchez, Ana; Salguero, Francisco Javier; Arráns, Rafael; Míguez Sánchez, Carlos; Walls Zurita, Amadeo; Romero Hermida, María Isabel; Leal, Antonio

    2012-03-01

    The purpose of this study was to present a Monte-Carlo (MC)-based optimization procedure to improve conventional treatment plans for accelerated partial breast irradiation (APBI) using modulated electron beams alone or combined with modulated photon beams, to be delivered by a single collimation device, i.e. a photon multi-leaf collimator (xMLC) already installed in a standard hospital. Five left-sided breast cases were retrospectively planned using modulated photon and/or electron beams with an in-house treatment planning system (TPS), called CARMEN, and based on MC simulations. For comparison, the same cases were also planned by a PINNACLE TPS using conventional inverse intensity modulated radiation therapy (IMRT). Normal tissue complication probability for pericarditis, pneumonitis and breast fibrosis was calculated. CARMEN plans showed similar acceptable planning target volume (PTV) coverage as conventional IMRT plans with 90% of PTV volume covered by the prescribed dose (Dp). Heart and ipsilateral lung receiving 5% Dp and 15% Dp, respectively, was 3.2-3.6 times lower for CARMEN plans. Ipsilateral breast receiving 50% Dp and 100% Dp was an average of 1.4-1.7 times lower for CARMEN plans. Skin and whole body low-dose volume was also reduced. Modulated photon and/or electron beams planned by the CARMEN TPS improve APBI treatments by increasing normal tissue sparing maintaining the same PTV coverage achieved by other techniques. The use of the xMLC, already installed in the linac, to collimate photon and electron beams favors the clinical implementation of APBI with the highest efficiency.

  2. X-ray interferometry with transmissive beam combiners for ultra-high angular resolution astronomy

    CERN Document Server

    Skinner, G K; 10.1007/s10686-009-9175-4

    2009-01-01

    Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event horizon of a super-massive black hole at the center of an active galaxy, can be achieved if beams from parts of the incoming wavefront separated by 100s of meters can be stably and accurately brought together at small angles. One way of achieving this is by using grazing incidence mirrors. We here investigate an alternative approach in which the beams are recombined by optical elements working in transmission. It is shown that the use of diffractive elements is a particularly attractive option. We report experimental results from a simple 2-beam interferometer using a low-cost commercially available profiled film as the diffractive elements. A rotationally symmetric filled (or mostly filled) aperture variant of such an interferometer, equivalent to an X-ray axicon, is shown to...

  3. X-ray Interferometry with Transmissive Beam Combiners for Ultra-High Angular Resolution Astronomy

    Science.gov (United States)

    Skinner, G. K.; Krismanic, John F.

    2009-01-01

    Abstract Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event horizon of a super-massive black hole at the center of an active galaxy, can be achieved if beams from parts of the incoming wavefront separated by 100s of meters can be stably and accurately brought together at small angles. One way of achieving this is by using grazing incidence mirrors. We here investigate an alternative approach in which the beams are recombined by optical elements working in transmission. It is shown that the use of diffractive elements is a particularly attractive option. We report experimental results from a simple 2-beam interferometer using a low-cost commercially available profiled film as the diffractive elements. A rotationally symmetric filled (or mostly filled) aperture variant of such an interferometer, equivalent to an X-ray axicon, is shown to offer a much wider bandpass than either a Phase Fresnel Lens (PFL) or a PFL with a refractive lens in an achromatic pair. Simulations of an example system are presented.

  4. The astronomical tables of Giovanni Bianchini

    CERN Document Server

    Chabas, Jose

    2009-01-01

    This book describes and analyses, for the first time, the astronomical tables of Giovanni Bianchini of Ferrara (d. after 1469), explains their context, inserts them into an astronomical tradition that began in Toledo, and addresses their diffusion.

  5. Engaging Students through Astronomically Inspired Music

    Science.gov (United States)

    Whitehouse, M.

    2011-09-01

    This paper describes a lesson outline in which astronomically inspired musical compositions are used to teach astronomical concepts via an introductory activity, close listening, and critical/creative reflection.

  6. Interactive Visualization and Simulation of Astronomical Nebulae

    CERN Document Server

    Wenger, Stephan; Steffen, Wolfgang; Koning, Nico; Weiskopf, Daniel; Magnor, Marcus

    2012-01-01

    Interactive visualization and simulation of astrophysical phenomena help astronomers and enable digital planetariums and television documentaries to take their spectators on a journey into deep space to explore the astronomical wonders of our universe in 3D.

  7. Leveraging data lineage to infer logical relationships between astronomical catalogs

    NARCIS (Netherlands)

    Buddelmeijer, Hugo; Valentijn, Edwin A.

    2013-01-01

    A novel method to infer logical relationships between sets is presented. These sets can be any collection of elements, for example astronomical catalogs of celestial objects. The method does not require the contents of the sets to be known explicitly. It combines incomplete knowledge about the relat

  8. The SAGE spectrometer: A tool for combined in-beam γ-ray and conversion electron spectroscopy

    International Nuclear Information System (INIS)

    The SAGE spectrometer allows simultaneous in-beam γ-ray and internal conversion electron measurements, by combining a germanium detector array with a highly segmented silicon detector and an electron transport system. SAGE is coupled with the ritu gas-filled recoil separator and the great focal-plane spectrometer for recoil-decay tagging studies. Digital electronics are used both for the γ ray and the electron parts of the spectrometer. SAGE was commissioned in the Accelerator Laboratory of the University of Jyvaeskylae in the beginning of 2010.

  9. Astronomical calibration of the Maastrichtian (Late Cretaceous)

    DEFF Research Database (Denmark)

    Husson, Dorothée; Galbrun, Bruno; Laskar, Jacques;

    2011-01-01

    Recent improvements to astronomical modeling of the Solar System have contributed to important refinements of the Cenozoic time scale through astronomical calibration of sedimentary series. We extend this astronomical calibration into the Cretaceous, on the base of the 405 ka orbital eccentricity...

  10. High Charge PHIN Photo Injector at CERN with Fast Phase switching within the Bunch Train for Beam Combination

    CERN Document Server

    Csatari Divall, M; Bolzon, B; Bravin, E; Chevallay, E; Dabrowski, A; Doebert, S; Drozdy, A; Fedosseev, V; Hessler, C; Lefevre, T; Livesley, S; Losito, R; Olvegaard, M; Petrarca, M; Rabiller, A N; Egger, D; Mete, O

    2011-01-01

    The high charge PHIN photo-injector was developed within the framework of the European CARE program to provide an alternative to the drive beam thermionic gun in the CTF3 (CLIC Test Facility) at CERN. In PHIN 1908 electron bunches are delivered with bunch spacing of 1.5 GHz and 2.33 nC charge per bunch. Furthermore the drive beam generated by CTF3 requires several fast 180 deg phase-shifts with respect to the 1.5 GHz bunch repetition frequency in order to allow the beam combination scheme developed at CTF3. A total of 8 subtrains, each 140 ns long and shifted in phase with respect to each other, have to be produced with very high phase and amplitude stability. A novel fiber modulator based phase-switching technique developed on the laser system provides this phase-shift between two consecutive pulses much faster and cleaner than the base line scheme, where a thermionic electron gun and sub-harmonic bunching are used. The paper describes the fiber-based switching system and the measurements verifying the schem...

  11. Combined effects of microwaves, electron beams and polyfunctional monomers on rubber vulcanization.

    Science.gov (United States)

    Manaila, Elena; Martin, Diana; Stelescu, Daniela Zuga; Craciun, Gabriela; Ighigeanu, Daniel; Matei, Constantin

    2009-01-01

    This paper presents comparative results obtained by conventional vulcanization with benzoyl peroxide (CV-BP), separate electron beam vulcanization (EB-V) and simultaneous electron beam and microwave vulcanization (EB+MW-V) applied to two kind of rubber samples: EVA (ethylene vinyl acetate) rubber-sample (EVA-sample) and EPDM (ethylene-propylene terpolymer) rubber-sample (EPDM-sample). The EVA-samples contain 61.54% EVA Elvax 260, 30.77% carbon black, 1.85% TAC (triallylcyanurate) polyfunctional monomer and 5.84% filler (zinc oxide, stearic acid, polyethylene glycol and antioxidant). The EPDM-samples contain 61.54% EPDM Nordel 4760, 30.77% carbon black, 1.85% TMPT (trimethylopropane trimethacrylate) polyfunctional monomer and 5.84% filler (zinc oxide, stearic acid, polyethylene glycol and antioxidant). The rubber samples designed for different vulcanization methods were obtained from raw rubber mixtures, as compressed sheets of 2 mm in the polyethylene foils to minimize oxidation. For EB and EB + MW treatments the sheets were cut in rectangular shape 0.15 x 0.15 m2. The physical properties of samples obtained by CV-BP EV-Vand EB + MW-V methods were evaluated by measuring the tearing strength, residual elongation, elongation at break, tensile strength, 300% modulus, 100% modulus, elasticity and hardness. The obtained results demonstrate an improvement of rubber several properties obtained by EB and EB + MW processing as compared to classical procedure using benzoyl peroxide. PMID:21384707

  12. Investigation of the combined effect of neutron irradiation and electron beam exposure on pure tungsten

    Science.gov (United States)

    Van Renterghem, W.; Uytdenhouwen, I.

    2016-08-01

    Pure tungsten samples were neutron irradiated in the BR2 reactor of SCK·CEN to fluences of 1.47 × 1020 n/cm2 and 4.74 × 1020 n/cm2 at 300 °C under Helium atmosphere and exposed to the electron beam of the Judith 1 installation The effect of these treatments on the defect structure was studied with transmission electron microscopy. In the irradiated samples the defect structure in the bulk is compared to the structure at the surface. The neutron irradiation created a large amount of a/2‹111› type dislocation loops forming dislocation rafts. The loop density increased from 8.5 × 1021/m³ to 9 × 1022/m³ with increasing dose, while the loop size decreased from 5.2 nm to 3.5 nm. The electron beam exposure induced significant annealing of the defects and almost all of the dislocation loops were removed. The number of line dislocations in that area increased as a result of the thermal stresses from the thermal shock.

  13. A combined crossed molecular beams and theoretical study of the reaction CN + C2H4

    International Nuclear Information System (INIS)

    Highlights: • The CN + C2H4 reaction was investigated in crossed beam experiments. • Electronic structure calculations of the potential energy surface were performed. • RRKM estimates qualitatively reproduce the experimental C2H3NC yield. - Abstract: The CN + C2H4 reaction has been investigated experimentally, in crossed molecular beam (CMB) experiments at the collision energy of 33.4 kJ/mol, and theoretically, by electronic structure calculations of the relevant potential energy surface and Rice–Ramsperger–Kassel–Marcus (RRKM) estimates of the product branching ratio. Differently from previous CMB experiments at lower collision energies, but similarly to a high energy study, we have some indication that a second reaction channel is open at this collision energy, the characteristics of which are consistent with the channel leading to CH2CHNC + H. The RRKM estimates using M06L electronic structure calculations qualitatively support the experimental observation of C2H3NC formation at this and at the higher collision energy of 42.7 kJ/mol of previous experiments

  14. Two-beam-combined 7.4J, 50 Hz Q-switch pulsed YAG laser system based on SBS phase conjugation mirror for plasma diagnostics

    International Nuclear Information System (INIS)

    The phase conjugation of the optically nonlinear stimulated Brillouin scattering (SBS) process using heavy-fluorocarbon materials effectively compensated thermal degradation at two amplifier lines, resulting in an output energy of 7.4J at 50 Hz. When combining two beams, the beat wave generation caused by the temporal coherence between the two beams can be prevented because the two beams leave at intervals longer than the coherence length of the pulse. The use of different Brillouin frequencies of reflection from different SBS substances can also be effective in preventing the interference effect caused by the spatial coherence between the two beams. (author)

  15. A high-speed, high-efficiency phase controller for coherent beam combining based on SPGD algorithm

    International Nuclear Information System (INIS)

    A phase controller for coherent beam combining (CBC) of fibre lasers has been designed and manufactured based on a stochastic parallel gradient descent (SPGD) algorithm and a field programmable gate array (FPGA). The theoretical analysis shows that the iteration rate is higher than 1.9 MHz, and the average compensation bandwidth of CBC for 5 or 20 channels is 50 kHz or 12.5 kHz, respectively. The tests show that the phase controller ensures reliable phase locking of lasers: When the phases of five lasers are locked by the improved control strategy with a variable gain, the energy encircled in the target is increased by 23 times than that in the single output, the phase control accuracy is better than λ/20, and the combining efficiency is 92%. (control of laser radiation parameters)

  16. Geopulsation, Volcanism and Astronomical Periods

    Institute of Scientific and Technical Information of China (English)

    Yang Xuexiang; Chen Dianyou; Yang Xiaoying; Yang Shuchen

    2000-01-01

    Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth's inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core - mantle boundary (CMB) to crust. When the earth' s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.

  17. Atmospheric Scintillation in Astronomical Photometry

    CERN Document Server

    Osborn, J; Dhillon, V S; Wilson, R W

    2015-01-01

    Scintillation noise due to the Earth's turbulent atmosphere can be a dominant noise source in high-precision astronomical photometry when observing bright targets from the ground. Here we describe the phenomenon of scintillation from its physical origins to its effect on photometry. We show that Young's (1967) scintillation-noise approximation used by many astronomers tends to underestimate the median scintillation noise at several major observatories around the world. We show that using median atmospheric optical turbulence profiles, which are now available for most sites, provides a better estimate of the expected scintillation noise and that real-time turbulence profiles can be used to precisely characterise the scintillation noise component of contemporaneous photometric measurements. This will enable a better understanding and calibration of photometric noise sources and the effectiveness of scintillation correction techniques. We also provide new equations for calculating scintillation noise, including ...

  18. Astronomical optics and elasticity theory

    CERN Document Server

    Lemaitre, Gerard Rene

    2008-01-01

    Astronomical Optics and Elasticity Theory provides a very thorough and comprehensive account of what is known in this field. After an extensive introduction to optics and elasticity, the book discusses variable curvature and multimode deformable mirrors, as well as, in depth, active optics, its theory and applications. Further, optical design utilizing the Schmidt concept and various types of Schmidt correctors, as well as the elasticity theory of thin plates and shells are elaborated upon. Several active optics methods are developed for obtaining aberration corrected diffraction gratings. Further, a weakly conical shell theory of elasticity is elaborated for the aspherization of grazing incidence telescope mirrors. The very didactic and fairly easy-to-read presentation of the topic will enable PhD students and young researchers to actively participate in challenging astronomical optics and instrumentation projects.

  19. National Astronomical Observatory of Japan

    CERN Document Server

    Haubold, Hans J; UN/ESA/NASA Workshop on the International Heliophysical Year 2007 and Basic Space Science, hosted by the National Astronomical Observatory of Japan

    2010-01-01

    This book represents Volume II of the Proceedings of the UN/ESA/NASA Workshop on the International Heliophysical Year 2007 and Basic Space Science, hosted by the National Astronomical Observatory of Japan, Tokyo, 18 - 22 June, 2007. It covers two programme topics explored in this and past workshops of this nature: (i) non-extensive statistical mechanics as applicable to astrophysics, addressing q-distribution, fractional reaction and diffusion, and the reaction coefficient, as well as the Mittag-Leffler function and (ii) the TRIPOD concept, developed for astronomical telescope facilities. The companion publication, Volume I of the proceedings of this workshop, is a special issue in the journal Earth, Moon, and Planets, Volume 104, Numbers 1-4, April 2009.

  20. Focus on astronomical predictable events

    DEFF Research Database (Denmark)

    Jacobsen, Aase Roland

    2006-01-01

    At the Steno Museum Planetarium we have for many occasions used a countdown clock to get focus om astronomical events. A countdown clock can provide actuality to predictable events, for example The Venus Transit, Opportunity landing on Mars and The Solar Eclipse. The movement of the clock attracs...... the public and makes a point of interest in a small exhibit area. A countdown clock can be simple, but it is possible to expand the concept to an eye-catching part of a museum.......At the Steno Museum Planetarium we have for many occasions used a countdown clock to get focus om astronomical events. A countdown clock can provide actuality to predictable events, for example The Venus Transit, Opportunity landing on Mars and The Solar Eclipse. The movement of the clock attracs...

  1. Astronomical Signatures of Dark Matter

    OpenAIRE

    Paul Gorenstein; Wallace Tucker

    2014-01-01

    Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitti...

  2. Sparse Representation of Astronomical Images

    OpenAIRE

    Rebollo-Neira, Laura; Bowley, James

    2012-01-01

    Sparse representation of astronomical images is discussed. It is shown that a significant gain in sparsity is achieved when particular mixed dictionaries are used for approximating these types of images with greedy selection strategies. Experiments are conducted to confirm: i)Effectiveness at producing sparse representations. ii)Competitiveness, with respect to the time required to process large images.The latter is a consequence of the suitability of the proposed dictionaries for approximati...

  3. Positioning accuracy of cone-beam computed tomography in combination with a HexaPOD robot treatment table

    International Nuclear Information System (INIS)

    Purpose: To scrutinize the positioning accuracy and reproducibility of a commercial hexapod robot treatment table (HRTT) in combination with a commercial cone-beam computed tomography system for image-guided radiotherapy (IGRT). Methods and Materials: The mechanical stability of the X-ray volume imaging (XVI) system was tested in terms of reproducibility and with a focus on the moveable parts, i.e., the influence of kV panel and the source arm on the reproducibility and accuracy of both bone and gray value registration using a head-and-neck phantom. In consecutive measurements the accuracy of the HRTT for translational, rotational, and a combination of translational and rotational corrections was investigated. The operational range of the HRTT was also determined and analyzed. Results: The system performance of the XVI system alone was very stable with mean translational and rotational errors of below 0.2 mm and below 0.2o, respectively. The mean positioning accuracy of the HRTT in combination with the XVI system summarized over all measurements was below 0.3 mm and below 0.3o for translational and rotational corrections, respectively. The gray value match was more accurate than the bone match. Conclusion: The XVI image acquisition and registration procedure were highly reproducible. Both translational and rotational positioning errors can be corrected very precisely with the HRTT. The HRTT is therefore well suited to complement cone-beam computed tomography to take full advantage of position correction in six degrees of freedom for IGRT. The combination of XVI and the HRTT has the potential to improve the accuracy of high-precision treatments

  4. Respiratory gated beam delivery cannot facilitate margin reduction, unless combined with respiratory correlated image guidance

    International Nuclear Information System (INIS)

    Purpose/objective: In radiotherapy of targets moving with respiration, beam gating is offered as a means of reducing the target motion. The purpose of this study is to evaluate the safe magnitude of margin reduction for respiratory gated beam delivery. Materials/methods: The study is based on data for 17 lung cancer patients in separate protocols at Rigshospitalet and Stanford Cancer Center. Respiratory curves for external optical markers and implanted fiducials were collected using equipment based on the RPM system (Varian Medical Systems). A total of 861 respiratory curves represented external measurements over 30 fraction treatment courses for 10 patients, and synchronous external/internal measurements in single sessions for seven patients. Variations in respiratory amplitude (simulated coaching) and external/internal phase shifts were simulated by perturbation with realistic values. Variations were described by medians and standard deviations (SDs) of position distributions of the markers. Gating windows (35% duty cycle) were retrospectively applied to the respiratory data for each session, mimicking the use of commercially available gating systems. Medians and SDs of gated data were compared to those of ungated data, to assess potential margin reductions. Results: External respiratory data collected over entire treatment courses showed SDs from 1.6 to 8.1 mm, the major part arising from baseline variations. The gated data had SDs from 1.5 to 7.7 mm, with a mean reduction of 0.3 mm (6%). Gated distributions were more skewed than ungated, and in a few cases a marginal miss of gated respiration would be found even if no margin reduction was applied. Regularization of breathing amplitude to simulate coaching did not alter these results significantly. Simulation of varying phase shifts between internal and external respiratory signals showed that the SDs of gated distributions were the same as for the ungated or smaller, but the median values were markedly shifted

  5. Armenian Astronomical Society Annual Activities in 2014

    Science.gov (United States)

    Mickaelian, A. M.

    2015-07-01

    A report is given on the achievements of the Armenian astronomy during the last year and on the present activities of the Armenian Astronomical Society (ArAS). ArAS membership, ArAS electronic newsletters (ArASNews), ArAS webpage, annual meetings, Annual Prize for Young Astronomers (Yervant Terzian Prize) and other awards, international relations, presence in international organizations, summer schools, astronomical Olympiads and other events, matters related to astronomical education, astronomical heritage, astronomy outreach and ArAS further projects are discussed. The present meeting, BAO Science Camp, ArAS School lectures are among 2014 events as well.

  6. Influence of external beam technique and brachytherapy quality assurance on the side effects in the combined external beam- and brachytherapy treatment of local advanced prostate cancer

    International Nuclear Information System (INIS)

    Transrectal ultrasound(TRUS) guided HDR implantation of the prostate has been established at the Kiel University by Bertermann and Brix in 1986 and there are to date 179 (T1b-T3 No Mo) patients treated in a combined modality. The dose for the implant was 2x 15 Gy on the capsule of the prostate in 14-20 days. For local and regional lymph nodes 20 Gy external beam therapy (AP-PA pelvic portals), 20 Gy with an individual transmission block (100% for subclinical disease, 70% and 50% according to the implant dosimetry for the prostate) and 10 Gy small volume irradiation for the prostate was applied, conventional fractioned. Total dose after the therapy 70 Gy for the prostate and 50 Gy for the subclinical disease in 6-7 weeks. As a quality control method we use since 1991 in vivo dosimetry on the medial rectum wall as well as in the prostatic part of the urethra. Regular follow-up 3-118 months after therapy (median 55) with PSA, digital rectal examination, control TRUS with volumetry (after one year with biopsy) and bone scan. There were no major early side effects within the first three months. Proctitis till 1991 with a duration up to 12 months 49%, prolonging more than one year in 23 %, (total proctitis 72.6%). Dysuria in up to 12 months 30 %, long lasting 30% (total number of dysuria 60 %). Erectile dysfunction in 56 %. Because of the number of the side effects 1991 we changed the external beam technique: instead of the biaxial arch therapy the AP-PA portals, and reduced irradiated volume (from 6480 cm3 to 5040 cm3). We introduced instead of the small volume arch therapy for 10 Gy external boost the box-technique with shielding the back part of the rectum and the upper part of the bladder resulting additional volume reduction. Through the 15 Gy HDR brachytherapy dose on the prostate capsule there are up to 8 Gy on the medial rectal wall, measured by in vivo dosimetry. This dose could not be responsible for the high number of side effects (see gynecological experience

  7. Structure and properties of the combined coatings deposited by the beams and plasma technologies

    International Nuclear Information System (INIS)

    Full text: The purpose of the given work is realization of complex researches of morphological features of a surface of powder coverings, definition of dependence of phase structure and mechanical characteristics (microhardness, wear resistance) from density of capacity of thermal influence on a surface of coverings of nickel alloys. In the given work it is submitted results of researches of three series of samples: a series No 1 - a covering in an initial condition, a series No 2 - pulsed-plasma melting a powder covering with partial melting surfaces of a substrate (depth melting made about 4 ·10-5 m), a series No 3 - full melting coverings an electron beam with melting substrates thickness from 1,5 up to 2·10-4 m. In work experimental results of research of structure, morphology and phase structure of plasma-detonation coverings from a powder on basis Ni, melted off by the concentrated streams of energy (a high-speed pulsed-plasma jet, an electron beam) are submitted. Element compositions of the surfaces were studied using electronic microscope REMMA-102. The phase structure of a surface was determined by means of x-ray diffraction (DRON-2). The microhardness was measured using PMT-3 with a diamond Vickers pyramid over the surface and the transversal and angular cross-sections. It is established, that duplex updating of a surface of plasma-detonation coverings on the basis of nickel is accompanied by the number of phase transformations in an initial material of a powder (formation of inter-metalloid compounds Cr2Ni2, CrB), and also enrichment of structure of a covering by an initial element of a matrix of a substrate (a-Fe) and its formation inter-metalloid connections with molybdenum (Fe7 Mo6, Fe3Mo and, probably, FeMo). Influence of phase structure on microhardness and wear resistance of the generated coatings is revealed. It is established, that electron melting surfaces it is accompanied by triple increase of microhardness of a superficial layer and twenty

  8. Combination of peptide receptor radionuclide therapy with fractionated external beam radiotherapy for treatment of advanced symptomatic meningioma

    International Nuclear Information System (INIS)

    External beam radiotherapy (EBRT) is the treatment of choice for irresectable meningioma. Due to the strong expression of somatostatin receptors, peptide receptor radionuclide therapy (PRRT) has been used in advanced cases. We assessed the feasibility and tolerability of a combination of both treatment modalities in advanced symptomatic meningioma. 10 patients with irresectable meningioma were treated with PRRT (177Lu-DOTA0,Tyr3 octreotate or - DOTA0,Tyr3 octreotide) followed by external beam radiotherapy (EBRT). EBRT performed after PRRT was continued over 5–6 weeks in IMRT technique (median dose: 53.0 Gy). All patients were assessed morphologically and by positron emission tomography (PET) before therapy and were restaged after 3–6 months. Side effects were evaluated according to CTCAE 4.0. Median tumor dose achieved by PRRT was 7.2 Gy. During PRRT and EBRT, no side effects > CTCAE grade 2 were noted. All patients reported stabilization or improvement of tumor-associated symptoms, no morphologic tumor progression was observed in MR-imaging (median follow-up: 13.4 months). The median pre-therapeutic SUVmax in the meningiomas was 14.2 (range: 4.3–68.7). All patients with a second PET after combined PRRT + EBRT showed an increase in SUVmax (median: 37%; range: 15%–46%) to a median value of 23.7 (range: 8.0–119.0; 7 patients) while PET-estimated volume generally decreased to 81 ± 21% of the initial volume. The combination of PRRT and EBRT is feasible and well tolerated. This approach represents an attractive strategy for the treatment of recurring or progressive symptomatic meningioma, which should be further evaluated

  9. Combining high power diode lasers using fiber bundles for beam delivery in optoacoustic endoscopy applications

    Science.gov (United States)

    Gawali, Sandeep Babu; Leggio, Luca; Sánchez, Miguel; Rodríguez, Sergio; Dadrasnia, Ehsan; Gallego, Daniel C.; Lamela, Horacio

    2016-05-01

    Optoacoustic (OA) effect refers to the generation of the acoustic waves due to absorption of light energy in a biological tissue. The incident laser pulse is absorbed by the tissue, resulting in the generation of ultrasound that is typically detected by a piezoelectric detector. Compared to other techniques, the advantage of OA imaging (OAI) technique consists in combining the high resolution of ultrasound technique with the high contrast of optical imaging. Generally, Nd:YAG and OPO systems are used for the generation of OA waves but their use in clinical environment is limited for many aspects. On the other hand, high-power diode lasers (HPDLs) emerge as potential alternative. However, the power of HPDLs is still relatively low compared to solid-state lasers. We show a side-by-side combination of several HPDLs in an optical fiber bundle to increase the amount of power for OA applications. Initially, we combine the output optical power of several HPDLs at 905 nm using two 7 to 1 round optical fiber bundles featuring a 675 μm and 1.2 mm bundle aperture. In a second step, we couple the output light of these fiber bundles to a 600 μm core diameter endoscopic fiber, reporting the corresponding coupling efficiencies. The fiber bundles with reasonable small diameter are likely to be used for providing sufficient light energy to potential OA endoscopy (OAE) applications.

  10. Astronomical Receiver Modelling Using Scattering Matrices

    CERN Document Server

    King, O G; Copley, C; Davis, R J; Leahy, J P; Leech, J; Muchovej, S J C; Pearson, T J; Taylor, Angela C

    2014-01-01

    Proper modelling of astronomical receivers is vital: it describes the systematic errors in the raw data, guides the receiver design process, and assists data calibration. In this paper we describe a method of analytically modelling the full signal and noise behaviour of arbitrarily complex radio receivers. We use electrical scattering matrices to describe the signal behaviour of individual components in the receiver, and noise correlation matrices to describe their noise behaviour. These are combined to produce the full receiver model. We apply this approach to a specified receiver architecture: a hybrid of a continous comparison radiometer and correlation polarimeter designed for the C-Band All-Sky Survey. We produce analytic descriptions of the receiver Mueller matrix and noise temperature, and discuss how imperfections in crucial components affect the raw data. Many of the conclusions drawn are generally applicable to correlation polarimeters and continuous comparison radiometers.

  11. On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

    Energy Technology Data Exchange (ETDEWEB)

    Borodi, Gheorghe

    2008-12-09

    The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22- pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4. Reactions of CO{sub 2}{sup +} with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H{sub 2} densities over the full temperature range of the apparatus (10 K-300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH{sup +}, CH{sub 2}{sup +}, and CH{sub 4}{sup +} have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. (orig.)

  12. On the combination of a low energy hydrogen atom beam with a cold multipole ion trap

    International Nuclear Information System (INIS)

    The first part of the activities of this thesis was to develop a sophisticated ion storage apparatus dedicated to study chemical processes with atomic hydrogen. The integration of a differentially pumped radical beam source into an existing temperature variable 22- pole trapping machine has required major modifications. Since astrophysical questions have been in the center of our interest, the introduction first gives a short overview of astrophysics and -chemistry. The basics of ion trapping in temperature variable rf traps is well-documented in the literature; therefore, the description of the basic instrument (Chapter 2) is kept rather short. Much effort has been put into the development of an intense and stable source for hydrogen atoms the kinetic energy of which can be changed. Chapter 3 describes this module in detail with emphasis on the integration of magnetic hexapoles for guiding the atoms and special treatments of the surfaces for reducing H-H recombination. Due to the unique sensitivity of the rf ion trapping technique, this instrument allows one to study a variety of reactions of astrochemical and fundamental interest. The results of this work are summarized in Chapter 4. Reactions of CO2+ with hydrogen atoms and molecules have been established as calibration standard for in situ determination of H and H2 densities over the full temperature range of the apparatus (10 K-300 K). For the first time, reactions of H- and D-atoms with the ionic hydrocarbons CH+, CH2+, and CH4+ have been studied at temperatures of interstellar space. A very interesting, not yet fully understood collision system is the interaction of protonated methane with H. The outlook presents some ideas, how to improve the new instrument and a few reaction systems are mentioned which may be studied next. (orig.)

  13. Combined external-beam PIXE and {mu}-Raman characterisation of garnets used in Merovingian jewellery

    Energy Technology Data Exchange (ETDEWEB)

    Calligaro, T. E-mail: thomas.calligaro@culture.gouv.fr; Colinart, S.; Poirot, J.-P.; Sudres, C

    2002-04-01

    Red garnets were the dominant gemstones used for jewels in Europe during the Early Middle Ages. We have studied over 350 garnets set on 12 jewels unearthed in the royal necropolis of the Saint-Denis Basilica, close to Paris. This famous collection of 'cloisonne' style artefacts dates from the Merovingian period (late fifth century AD to early seventh century AD). The archaeological issue addressed is the identification of the geographical origin of these garnets, in view to establish the gem trading routes during the Dark Ages. External beam PIXE was used to determine the major constituents (Mg, Al, Si, Ca, Mn, Fe), specifying the garnet type (composition in various mineralogical end-members, e.g. almandine, pyrope, spessartite, ...), and the trace element content (Cr, Y). Three sorts of garnets were identified. Ten jewels are adorned with almandine garnets (Fe-rich). One jewel has intermediate almandine-pyrope garnets ('rhodolite'). The last and most recent jewel is inlaid with pyrope (Mg-rich) garnets. Trace element content and slight differences in major composition allowed to distinguish five different sources: two sources for pyrope garnets (with and without chromium), and two sources for almandine garnets (distinctive calcium, magnesium and yttrium contents). A preliminary comparison with literature data suggested that almandine garnets may have been mined from India while the 'rhodolite' garnets may have been imported from Sri Lanka. The sources of pyrope garnets could be the Bohemian deposits (Czech republic). In addition, {mu}-Raman spectrometry was used to identify most of the mineral inclusions (apatite, zircon, ilmenite, monazite, calcite, quartz) present in almandine garnets. Even if two specific types of inclusions were not identified, due to the lack of corresponding reference spectra in our database, the Raman spectra collected provided an interesting inclusion fingerprint.

  14. Combined external-beam PIXE and μ-Raman characterisation of garnets used in Merovingian jewellery

    International Nuclear Information System (INIS)

    Red garnets were the dominant gemstones used for jewels in Europe during the Early Middle Ages. We have studied over 350 garnets set on 12 jewels unearthed in the royal necropolis of the Saint-Denis Basilica, close to Paris. This famous collection of 'cloisonne' style artefacts dates from the Merovingian period (late fifth century AD to early seventh century AD). The archaeological issue addressed is the identification of the geographical origin of these garnets, in view to establish the gem trading routes during the Dark Ages. External beam PIXE was used to determine the major constituents (Mg, Al, Si, Ca, Mn, Fe), specifying the garnet type (composition in various mineralogical end-members, e.g. almandine, pyrope, spessartite, ...), and the trace element content (Cr, Y). Three sorts of garnets were identified. Ten jewels are adorned with almandine garnets (Fe-rich). One jewel has intermediate almandine-pyrope garnets ('rhodolite'). The last and most recent jewel is inlaid with pyrope (Mg-rich) garnets. Trace element content and slight differences in major composition allowed to distinguish five different sources: two sources for pyrope garnets (with and without chromium), and two sources for almandine garnets (distinctive calcium, magnesium and yttrium contents). A preliminary comparison with literature data suggested that almandine garnets may have been mined from India while the 'rhodolite' garnets may have been imported from Sri Lanka. The sources of pyrope garnets could be the Bohemian deposits (Czech republic). In addition, μ-Raman spectrometry was used to identify most of the mineral inclusions (apatite, zircon, ilmenite, monazite, calcite, quartz) present in almandine garnets. Even if two specific types of inclusions were not identified, due to the lack of corresponding reference spectra in our database, the Raman spectra collected provided an interesting inclusion fingerprint

  15. Combined external-beam PIXE and /μ-Raman characterisation of garnets used in Merovingian jewellery

    Science.gov (United States)

    Calligaro, T.; Colinart, S.; Poirot, J.-P.; Sudres, C.

    2002-04-01

    Red garnets were the dominant gemstones used for jewels in Europe during the Early Middle Ages. We have studied over 350 garnets set on 12 jewels unearthed in the royal necropolis of the Saint-Denis Basilica, close to Paris. This famous collection of "cloisonné" style artefacts dates from the Merovingian period (late fifth century AD to early seventh century AD). The archaeological issue addressed is the identification of the geographical origin of these garnets, in view to establish the gem trading routes during the Dark Ages. External beam PIXE was used to determine the major constituents (Mg, Al, Si, Ca, Mn, Fe), specifying the garnet type (composition in various mineralogical end-members, e.g. almandine, pyrope, spessartite, …), and the trace element content (Cr, Y). Three sorts of garnets were identified. Ten jewels are adorned with almandine garnets (Fe-rich). One jewel has intermediate almandine-pyrope garnets ("rhodolite"). The last and most recent jewel is inlaid with pyrope (Mg-rich) garnets. Trace element content and slight differences in major composition allowed to distinguish five different sources: two sources for pyrope garnets (with and without chromium), and two sources for almandine garnets (distinctive calcium, magnesium and yttrium contents). A preliminary comparison with literature data suggested that almandine garnets may have been mined from India while the "rhodolite" garnets may have been imported from Sri Lanka. The sources of pyrope garnets could be the Bohemian deposits (Czech republic). In addition, μ-Raman spectrometry was used to identify most of the mineral inclusions (apatite, zircon, ilmenite, monazite, calcite, quartz) present in almandine garnets. Even if two specific types of inclusions were not identified, due to the lack of corresponding reference spectra in our database, the Raman spectra collected provided an interesting inclusion fingerprint.

  16. Astronomical measurement a concise guide

    CERN Document Server

    Lawrence, Andy

    2014-01-01

    This book on astronomical measurement takes a fresh approach to teaching the subject. After discussing some general principles, it follows the chain of measurement through atmosphere, imaging, detection, spectroscopy, timing, and hypothesis testing. The various wavelength regimes are covered in each section, emphasising what is the same, and what is different. The author concentrates on the physics of detection and the principles of measurement, aiming to make this logically coherent. The book is based on a short self contained lecture course for advanced undergraduate students developed and taught by the author over several years.

  17. Combining different modes of high-power ion beam application for creation of metallic and diamond-like coatings

    International Nuclear Information System (INIS)

    Some results of the experiments on thin film deposition using pulsed high-power ion beam (HPIB) are reported. Ti, Nb, Pt, and C films were produced from ablation plasma generated under the action of pulsed HPIB on a surface of ablated materials. We are developing the combined technology that deals with cleaning a substrate surface by HPIB, thin film deposition by HPIB, and the radiation-induced mass transfer of elements of both film and substrate to increase the adhesion. The deposition of the diamond-like titanium carbide has been realized on the basis of the scheme including Ti film deposition. C film deposition, and the ion beam mixing to form TiC carbide. The main parameters of the Ti-substrate transition layers have been determined for different regimes of their creation by Rutherford backscattering (RBS). Ti, Nb, and Pt coatings were deposited on silicon cantilevers used in high-resolution scanning probe microscopes. The analysis of the composition of TiC coatings at a substrate was performed using the Auger electron spectroscopy (AES) method

  18. A combined SNMS and EFTEM/EELS study on focused ion beam prepared vanadium nitride thin films

    Science.gov (United States)

    Kothleitner, Gerald; Rogers, M.; Berendes, A.; Bock, W.; Kolbesen, B. O.

    2005-09-01

    We investigated the diffusion profiles and core-loss fine-structures (ELNES) of thin vanadium nitride films by electron energy-loss spectroscopy (EELS) and energy filtering transmission electron microscopy (EFTEM). The nitride layers have been produced by rapid thermal processing in a NH 3 or N 2 atmosphere and have then been cross-sectioned with a focused ion beam instrument (FIB) under mild milling conditions to maintain crystallography. For the high-resolution electron energy-loss spectroscopy studies (HREELS), a recently developed TEM gun monochromator, implemented into a 200 kV field emission gun column was used in combination with a new post-column spectrometer. It was found that, dependent on substrate and atmosphere, layers with different vanadium and nitrogen content were formed, showing distinct differences in their ELNES. With an energy resolution at the 0.2 eV level and a TEM beam spot size of approximately 2 nm these layers could be unambiguously identified when compared to theoretical ELNES simulations from the literature.

  19. Depth profiling using total reflection X-ray fluorescence spectrometry alone and in combination with ion beam sputtering

    Science.gov (United States)

    Schwenke, H.; Knoth, J.; Günther, R.; Wiener, G.; Bormann, R.

    1997-07-01

    The capability of total reflection X-ray fluorescence spectrometry (TXRF) for depth profiling is examined by means of selected examples including organometallic layers, an implantation profile of arsenic in silicon and a layered nickel/cobalt structure. For structures without density differences that are deeper than 20 nm or so, and also for buried layers and for the examination of sharp interfaces, which require the highest resolution, two different combinations of ion beam sputtering with TXRF have been employed. A microsectioning technique was investigated in which samples were etched to a bevel shape and subsequently scanned by TXRF. A depth resolution of 2.5 nm was obtained. Alternatively, the so called "transfer technique" was investigated. This involves surface atoms being sputtered by an ion beam and immediately deposited on a silicon wafer rotated behind a slit which is moved in step with the sputter progress. Subsequently, the wafer is scanned by TXRF. Using this technique, the width of a coherent Ti/Al interface within a layered structure was measured to be 1.4 nm. The depth resolutions of the "microsectioning" and the "transfer" techniques are compared with data from RBS, XPS, SIMS and SNMS.

  20. Time-variant flexural reliability of RC beams with externally bonded CFRP under combined fatigue-corrosion actions

    International Nuclear Information System (INIS)

    Time-variant reliability analysis of RC highway bridges strengthened with carbon fibre reinforced polymer CFRP laminates under four possible competing damage modes (concrete crushing, steel rupture after yielding, CFRP rupture and FRP plate debonding) and three degradation factors is analyzed in terms of reliability index β using FORM. The first degradation factor is chloride-attack corrosion which induces reduction in steel area and concrete cover cracking at characteristic key times (corrosion initiation, severe surface cover cracking). The second degradation factor considered is fatigue which leads to damage in concrete and steel rebar. Interaction between corrosion and fatigue crack growth in steel reinforcing bars is implemented. The third degradation phenomenon is the CFRP properties deterioration due to aging. Considering these three degradation factors, the time-dependent flexural reliability profile of a typical simple 15 m-span intermediate girder of a RC highway bridge is constructed under various traffic volumes and under different corrosion environments. The bridge design options follow AASHTO-LRFD specifications. Results of the study have shown that the reliability is very sensitive to factors governing the corrosion. Concrete damage due to fatigue slightly affects reliability profile of non-strengthened section, while service life after strengthening is strongly related to fatigue damage in concrete. - Highlights: • We propose a method to follow the time-variant reliability of strengthened RC beams. • We consider multiple competing failure modes of CFRP strengthened RC beams. • We consider combined degradation mechanisms (corrosion, fatigue, ageing of CFRP)

  1. A study on port plug distortion caused by narrow gap combined GTAW and SMAW and Electron Beam Welding

    International Nuclear Information System (INIS)

    A study of port plug distortion resulting from narrow gap combined GTAW and SMAW and Electron Beam Welding was carried out. Thermomechanical finite element analysis of port plug becomes virtually impossible because of the requirement of huge number of nodes and elements. Hence an analysis method based on the concept of inherent strain was used in this work. The computational time required was about 40-50 min only in a Core (TM) 2 Duo, 2.66 GHz computer with 2 GB RAM, which otherwise was not possible with other conventional computation techniques. As was expected the overall distortion due to EB welding was found to be less compared to that of narrow gap GTAW and SMAW.

  2. Application of the combined electrochemical quartz crystal microbalance and probe beam deflection technique in deep eutectic solvents

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The EQCM/PBD method has for the first time been applied to metal deposition/dissolution processes in deep eutectic solvents • The PBD responds to solution phase chemistry, while the E and QCM probes respond to interfacial processes only • The combination of electrochemical (E), gravimetric (QCM) and optical (PBD) responses provides diagnostic capability • EQCM/PBD data reveal the influence of Ag/Cl− complex speciation in the high chloride concentration ionic liquid • The PBD response reveals the intrusion of solubility limitations into Sn anodic stripping - Abstract: The electrochemical quartz crystal microbalance (EQCM) and probe beam deflection (PBD) have been widely used to study interfacial processes in molecular solvent-based electrolytes. However, there has been limited use of the EQCM and none of PBD in room temperature ionic liquids, including deep eutectic solvents (DES). Here we explore the use of the combined EQCM/PBD technique to the study of Ag and Sn electrodeposition from a DES comprising a 1:2 mixture of choline chloride and ethylene glycol. While overcoming the effect of viscous loss in the acoustic wave (EQCM) part of the experiment is understood, the optical (PBD) technique fails to provide a meaningful response in slow scan rate voltammetric experiments; this contrasts sharply with the straightforward behaviour seen in aqueous media. Solution transport considerations reveal this to be a consequence of long surface-to-beam transit times in the viscous DES. The problem can be overcome by operating at scan rates 1-2 orders of magnitude slower, permitting application of this powerful technique to novel media of technological interest. The PBD responses reveal unanticipated chemical effects: multiple complexes in the Ag system and solubility limitations in the Sn system, neither of which is evident from the electrochemical or QCM responses

  3. Explanatory supplement to the astronomical almanac

    CERN Document Server

    Urban, Sean E

    2013-01-01

    The Explanatory Supplement to the Astronomical Almanac offers explanatory material, supplemental information and detailed descriptions of the computational models and algorithms used to produce The Astronomical Almanac, which is an annual publication prepared jointly by the US Naval Observatory and Her Majesty's Nautical Almanac Office in the UK. Like The Astronomical Almanac, The Explanatory Supplement provides detailed coverage of modern positional astronomy. Chapters are devoted to the celestial and terrestrial reference frames, orbital ephemerides, precession, nutation, Earth rotation, and coordinate transformations. These topics have undergone substantial revisions since the last edition was published. Astronomical positions are intertwined with timescales and relativity in The Astronomical Almanac, so related chapters are provided in The Explanatory Supplement. The Astronomical Almanac also includes information on lunar and solar eclipses, physical ephemerides of solar system bodies, and calendars, so T...

  4. A Visible, Spatially-Modulated Imaging Fourier Transform Spectrometer (SMIFTS) for Astronomical Applications

    Science.gov (United States)

    Rafert, J. B.; Holbert, E. T.; Rusk, E. T.; Durham, S. E.; Caudill, E.; Keating, D.; Newby, H.

    1992-12-01

    We have constructed several visible, Spatially-Modulated Imaging Fourier Transform Spectrometers (SMIFTS) for spatially resolved spectral imaging in the visible wavelength region based on work by several authors including Yoshihara and Kitade (1967), Okamoto et al. (1984), Barnes (1985) and Smith and Schempp (1991). Our spectrometers require no moving parts, are compact and enjoy a number of advantages over the other spectral data collection technologies. The unique combination of characteristics define an important niche for astronomical, remote sensing, and reconnaissance spectral data acquisition. Our SMIFTS simultaneously acquires hundreds or thousands of spectral bands for hundreds or thousands of spectral channesl. This type of sensor has been called a "hyperspectral" sensor to emphasize the major quantitative difference between this type of sensor and multispectral imagers which collect only a few spectral bands. The SMIFTS consists of input optics (a telescope), a field limiting aperture, a beamsplitter which divides the input beam into two paths, two mirrors which redirect the split beams through the same path, a collimating lens which forms the interferogram of the input aperture on the detector plane, and a cylindrical imaging lens. Thus on the detector array one axis contains spatial information and the other axis contains the spectral information for each point of the spatial axis. The result of this arrangement is that each row of the detector array contains the interferogram of the corresponding point on the aperture or slit. This slit can be fixed upon the target, or the slit can be scanned across the target to build up a second axis of spatial information resulting in a data set with four dimensions: two spatial, one spectral, and one temporal. We present sample data for both astronomical and remote sensing applications taken with the Malabar SMIFTS. Barnes, T.H. "Photodiode Array Fourier Transform Spectrometer with Improved Dynamic Range", Appl

  5. The League of Astronomers: Outreach

    Science.gov (United States)

    Paat, Anthony; Brandel, A.; Schmitz, D.; Sharma, R.; Thomas, N. H.; Trujillo, J.; Laws, C. S.; Astronomers, League of

    2014-01-01

    The University of Washington League of Astronomers (LOA) is an organization comprised of University of Washington (UW) undergraduate students. Our main goal is to share our interest in astronomy with the UW community and with the general public. The LOA hosts star parties on the UW campus and collaborates with the Seattle Astronomical Society (SAS) on larger Seattle-area star parties. At the star parties, we strive to teach our local community about what they can view in our night sky. LOA members share knowledge of how to locate constellations and use a star wheel. The relationship the LOA has with members of SAS increases both the number of events and people we are able to reach. Since the cloudy skies of the Northwest prevent winter star parties, we therefore focus our outreach on the UW Mobile Planetarium, an inflatable dome system utilizing Microsoft’s WorldWide Telescope (WWT) software. The mobile planetarium brings astronomy into the classrooms of schools unable to travel to the UW on-campus planetarium. Members of the LOA volunteer their time towards this project and we make up the majority of the Mobile Planetarium volunteers. Our outreach efforts allow us to connect with the community and enhance our own knowledge of astronomy.

  6. Astronomical Signatures of Dark Matter

    Directory of Open Access Journals (Sweden)

    Paul Gorenstein

    2014-01-01

    Full Text Available Several independent astronomical observations in different wavelength bands reveal the existence of much larger quantities of matter than what we would deduce from assuming a solar mass to light ratio. They are very high velocities of individual galaxies within clusters of galaxies, higher than expected rotation rates of stars in the outer regions of galaxies, 21 cm line studies indicative of increasing mass to light ratios with radius in the halos of spiral galaxies, hot gaseous X-ray emitting halos around many elliptical galaxies, and clusters of galaxies requiring a much larger component of unseen mass for the hot gas to be bound. The level of gravitational attraction needed for the spatial distribution of galaxies to evolve from the small perturbations implied by the very slightly anisotropic cosmic microwave background radiation to its current web-like configuration requires much more mass than is observed across the entire electromagnetic spectrum. Distorted shapes of galaxies and other features created by gravitational lensing in the images of many astronomical objects require an amount of dark matter consistent with other estimates. The unambiguous detection of dark matter and more recently evidence for dark energy has positioned astronomy at the frontier of fundamental physics as it was in the 17th century.

  7. Processing Color in Astronomical Imagery

    CERN Document Server

    Arcand, Kimberly K; Rector, Travis; Levay, Zoltan G; DePasquale, Joseph; Smarr, Olivia

    2013-01-01

    Every year, hundreds of images from telescopes on the ground and in space are released to the public, making their way into popular culture through everything from computer screens to postage stamps. These images span the entire electromagnetic spectrum from radio waves to infrared light to X-rays and gamma rays, a majority of which is undetectable to the human eye without technology. Once these data are collected, one or more specialists must process the data to create an image. Therefore, the creation of astronomical imagery involves a series of choices. How do these choices affect the comprehension of the science behind the images? What is the best way to represent data to a non-expert? Should these choices be based on aesthetics, scientific veracity, or is it possible to satisfy both? This paper reviews just one choice out of the many made by astronomical image processors: color. The choice of color is one of the most fundamental when creating an image taken with modern telescopes. We briefly explore the ...

  8. LGBT Workplace Issues for Astronomers

    Science.gov (United States)

    Kay, Laura E.; Danner, R.; Sellgren, K.; Dixon, V.; GLBTQastro

    2011-01-01

    Federal Equal Employment Opportunity laws and regulations do not provide protection from discrimination on the basis of sexual orientation or gender identity or gender expression. Sexual minority astronomers (including lesbian, gay, bisexual and transgender people; LGBT) can face additional challenges at school and work. Studies show that LGBT students on many campuses report experiences of harassment. Cities, counties, and states may or may not have statutes to protect against such discrimination. There is wide variation in how states and insurance plans handle legal and medical issues for transgender people. Federal law does not acknowledge same-sex partners, including those legally married in the U.S. or in other countries. Immigration rules in the U.S. (and many other, but not all) countries do not recognize same-sex partners for visas, employment, etc. State `defense of marriage act' laws have been used to remove existing domestic partner benefits at some institutions, or benefits can disappear with a change in governor. LGBT astronomers who change schools, institutions, or countries during their career may experience significant differences in their legal, medical, and marital status.

  9. The feasibility and safety of high-intensity focused ultrasound combined with low-dose external beam radiotherapy as supplemental therapy for advanced prostate cancer following hormonal therapy

    OpenAIRE

    Wu, Rui-Yi; Wang, Guo-Min; Xu, Lei; ZHANG, BO-HENG; Xu, Ye-Qing; Zeng, Zhao-Chong; Chen, Bing

    2011-01-01

    The aim of this study was to investigate the feasibility and safety of high-intensity focused ultrasound (HIFU) combined with (+) low-dose external beam radiotherapy (LRT) as supplemental therapy for advanced prostate cancer (PCa) following hormonal therapy (HT). Our definition of HIFU+LRT refers to treating primary tumour lesions with HIFU in place of reduced field boost irradiation to the prostate, while retaining four-field box irradiation to the pelvis in conventional-dose external beam r...

  10. Vision: A Six-telescope Fiber-fed Visible Light Beam Combiner for the Navy Precision Optical Interferometer

    Science.gov (United States)

    Garcia, Eugenio V.; Muterspaugh, Matthew W.; van Belle, Gerard; Monnier, John D.; Stassun, Keivan G.; Ghasempour, Askari; Clark, James H.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Schmitt, Henrique R.; Baines, Ellyn K.; Jorgensen, Anders M.; Strosahl, Susan G.; Sanborn, Jason; Zawicki, Stephen J.; Sakosky, Michael F.; Swihart, Samuel

    2016-05-01

    Visible-light long baseline interferometry holds the promise of advancing a number of important applications in fundamental astronomy, including the direct measurement of the angular diameters and oblateness of stars, and the direct measurement of the orbits of binary and multiple star systems. To advance, the field of visible-light interferometry requires development of instruments capable of combining light from 15 baselines (6 telescopes) simultaneously. The Visible Imaging System for Interferometric Observations at NPOI (VISION) is a new visible light beam combiner for the Navy Precision Optical Interferometer (NPOI) that uses single-mode fibers to coherently combine light from up to six telescopes simultaneously with an image-plane combination scheme. It features a photometric camera for calibrations and spatial filtering from single-mode fibers with two Andor Ixon electron multiplying CCDs. This paper presents the VISION system, results of laboratory tests, and results of commissioning on-sky observations. A new set of corrections have been determined for the power spectrum and bispectrum by taking into account non-Gaussian statistics and read noise present in electron-multipying CCDs to enable measurement of visibilities and closure phases in the VISION post-processing pipeline. The post-processing pipeline has been verified via new on-sky observations of the O-type supergiant binary ζ Orionis A, obtaining a flux ratio of 2.18+/- 0.13 with a position angle of 223.°9 ± 1.°0 and separation 40.6+/- 1.8 mas over 570–750 nm, in good agreement with expectations from the previously published orbit.

  11. Vision: A Six-telescope Fiber-fed Visible Light Beam Combiner for the Navy Precision Optical Interferometer

    Science.gov (United States)

    Garcia, Eugenio V.; Muterspaugh, Matthew W.; van Belle, Gerard; Monnier, John D.; Stassun, Keivan G.; Ghasempour, Askari; Clark, James H.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Schmitt, Henrique R.; Baines, Ellyn K.; Jorgensen, Anders M.; Strosahl, Susan G.; Sanborn, Jason; Zawicki, Stephen J.; Sakosky, Michael F.; Swihart, Samuel

    2016-05-01

    Visible-light long baseline interferometry holds the promise of advancing a number of important applications in fundamental astronomy, including the direct measurement of the angular diameters and oblateness of stars, and the direct measurement of the orbits of binary and multiple star systems. To advance, the field of visible-light interferometry requires development of instruments capable of combining light from 15 baselines (6 telescopes) simultaneously. The Visible Imaging System for Interferometric Observations at NPOI (VISION) is a new visible light beam combiner for the Navy Precision Optical Interferometer (NPOI) that uses single-mode fibers to coherently combine light from up to six telescopes simultaneously with an image-plane combination scheme. It features a photometric camera for calibrations and spatial filtering from single-mode fibers with two Andor Ixon electron multiplying CCDs. This paper presents the VISION system, results of laboratory tests, and results of commissioning on-sky observations. A new set of corrections have been determined for the power spectrum and bispectrum by taking into account non-Gaussian statistics and read noise present in electron-multipying CCDs to enable measurement of visibilities and closure phases in the VISION post-processing pipeline. The post-processing pipeline has been verified via new on-sky observations of the O-type supergiant binary ζ Orionis A, obtaining a flux ratio of 2.18+/- 0.13 with a position angle of 223.°9 ± 1.°0 and separation 40.6+/- 1.8 mas over 570-750 nm, in good agreement with expectations from the previously published orbit.

  12. Astronomical Symbolism in Australian Aboriginal Rock Art

    CERN Document Server

    Norris, Ray P

    2010-01-01

    Traditional Aboriginal Australian cultures include a significant astronomical component, perpetuated through oral tradition and ceremony. This knowledge has practical navigational and calendrical functions, and sometimes extends to a deep understanding of the motion of objects in the sky. Here we explore whether this astronomical tradition is reflected in the rock art of Aboriginal Australians. We find several plausible examples of depictions of astronomical figures and symbols, and also evidence that astronomical observations were used to set out stone arrangements. However, we recognise that the case is not yet strong enough to make an unequivocal statement, and describe our plans for further research.

  13. Astronomical Symbolism in Australian Aboriginal Rock Art

    Science.gov (United States)

    Norris, Ray P.; Hamacher, Duane W.

    2011-05-01

    Traditional Aboriginal Australian cultures include a significant astronomical component, perpetuated through oral tradition and ceremony. This knowledge has practical navigational and calendrical functions, and sometimes extends to a deep understanding of the motion of objects in the sky. Here we explore whether this astronomical tradition is reflected in the rock art of Aboriginal Australians. We find several plausible examples of depictions of astronomical figures and symbols, and also evidence that astronomical observations were used to set out stone arrangements. However, we recognise that the case is not yet strong enough to make an unequivocal statement, and describe our plans for further research.

  14. Effects of electron beam irradiation combined with hot water immersion treatment for shelf life extension of bananas

    International Nuclear Information System (INIS)

    A study of the effects of minimal processing treatments, both individually or in combinations, was carried out in order to extend the shelf life and to improve the quality of bananas. Pre climacteric bananas at light full three-quarter grade, were either treated with hot water immersion for 1-30 min at 45-55 degree C, or irradiated with electron beams (2.0 MeV, Van de Graaff accelerator), to a dose of 0.1-1.5 kGy. All fruit was stored at 21 ± 1 degree C and relative humidity of 85-95 %. There was no significant delay in ripening of fruit treated with hot water immersion at the above temperatures. Some damage to fruit particularly peel scalding at ends occurred at the higher temperatures (>50 degree C). The 50 degree C, 5 minutes immersion was selected for further study. Irradiation to 0.1-0.3 kGy delayed the ripening (up to 3 days) without affecting fruit quality. Doses greater than 0.4 kGy resulted in extensive discoloration and fruit splitting. No significant differences could be detected organoleptically between bananas irradiated at 0.15 kGy and the control. Results of the physico-chemical attributes of the bananas were reported for fruits at colour stage 5 and after 10 and 15 days of storage. The combination treatment of hot water immersion and irradiation at the above settings further extended the shelf life of the banana fruits

  15. Osteogenesis effect of guided bone regeneration combined with alveolar cleft grafting: assessment by cone beam computed tomography.

    Science.gov (United States)

    Xiao, W-L; Zhang, D-Z; Chen, X-J; Yuan, C; Xue, L-F

    2016-06-01

    Cone beam computed tomography (CBCT) allows for a significantly lower radiation dose than conventional computed tomography (CT) scans and provides accurate images of the alveolar cleft area. The osteogenic effect of guided bone regeneration (GBR) vs. conventional alveolar bone grafting alone for alveolar cleft defects was evaluated in this study. Sixty alveolar cleft patients were divided randomly into two groups. One group underwent GBR using acellular dermal matrix film combined with alveolar bone grafting using iliac crest bone grafts (GBR group), while the other group underwent alveolar bone grafting only (non-GBR group). CBCT images were obtained at 1 week and at 3 months following the procedure. Using Simplant 11.04 software, the bone resorption rate was calculated and compared between the two groups. The bone resorption rate from 1 week to 3 months following bone grafting without the GBR technique was 36.50±5.04%, whereas the bone resorption rate using the GBR technique was 31.69±5.50% (P=0.017). The application of autogenous iliac bone combined with the GBR technique for alveolar bone grafting of alveolar cleft patients can reduce bone resorption and result in better osteogenesis. PMID:26876144

  16. BOOK REVIEW: The Wandering Astronomer

    Science.gov (United States)

    Swinbank, Elizabeth

    2000-09-01

    Fans of Patrick Moore will like this book. I enjoyed it more than I expected, having anticipated a collection of personal anecdotes of the type favoured by certain tedious after-dinner speakers. Some of the 41 short items it contains do tend towards that category, but there are also some nuggets which might enliven your physics teaching. For example, did you know that, in a murder trial in 1787, the defendant's belief that the Sun was inhabited was cited as evidence of his insanity? This was despite his views being shared by many astronomers of the day including William Herschel. Or that Clyde Tombaugh had a cat called Pluto after the planet he discovered, which was itself named by an eleven-year-old girl? Another gem concerns a brief flurry, in the early 1990s, over a suspected planet orbiting a pulsar; variations in the arrival time of its radio pulses indicated the presence of an orbiting body. These shifts were later found to arise from an error in a computer program that corrected for the Earth's motion. The programmer had assumed a circular orbit for the Earth whereas it is actually elliptical. The book is clearly intended for amateur astronomers and followers of Patrick Moore's TV programmes. There is plenty of astronomy, with an emphasis on the solar system, but very little astrophysics. The author's metricophobia means that quantities are given in imperial units throughout, with metric equivalents added in brackets (by an editor, I suspect) which can get irritating, particularly as powers-of-ten notation is avoided. It is quite a novelty to see the temperature for hydrogen fusion quoted as 18 000 000 °F (10 000 000 °C). By way of contrast, astronomical terms are used freely - ecliptic, first-magnitude star, and so on. Such terms are defined in a glossary at the end, but attention is not drawn to this and I only stumbled across it by chance. Patrick Moore obviously knows his public, and this book will serve them well. For physics teachers and students

  17. IAU Public Astronomical Organisations Network

    Science.gov (United States)

    Canas, Lina; Cheung, Sze Leung

    2015-08-01

    The Office for Astronomy Outreach has devoted intensive means to create and support a global network of public astronomical organisations around the world. Focused on bringing established and newly formed amateur astronomy organizations together, providing communications channels and platforms for disseminating news to the global community and the sharing of best practices and resources among these associations around the world. In establishing the importance that these organizations have for the dissemination of activities globally and acting as key participants in IAU various campaigns social media has played a key role in keeping this network engaged and connected. Here we discuss the implementation process of maintaining this extensive network, the processing and gathering of information and the interactions between local active members at a national and international level.

  18. Detecting bimodality in astronomical datasets

    Science.gov (United States)

    Ashman, Keith A.; Bird, Christina M.; Zepf, Stephen E.

    1994-01-01

    We discuss statistical techniques for detecting and quantifying bimodality in astronomical datasets. We concentrate on the KMM algorithm, which estimates the statistical significance of bimodality in such datasets and objectively partitions data into subpopulations. By simulating bimodal distributions with a range of properties we investigate the sensitivity of KMM to datasets with varying characteristics. Our results facilitate the planning of optimal observing strategies for systems where bimodality is suspected. Mixture-modeling algorithms similar to the KMM algorithm have been used in previous studies to partition the stellar population of the Milky Way into subsystems. We illustrate the broad applicability of KMM by analyzing published data on globular cluster metallicity distributions, velocity distributions of galaxies in clusters, and burst durations of gamma-ray sources. FORTRAN code for the KMM algorithm and directions for its use are available from the authors upon request.

  19. Christopher Clavius astronomer and mathematician

    CERN Document Server

    Sigismondi, Costantino

    2012-01-01

    The Jesuit scientist Christopher Clavius (1538-1612) has been the most influential teacher of the renaissance. His contributions to algebra, geometry, astronomy and cartography are enormous. He paved the way, with his texts and his teaching for 40 years in the the Collegio Romano, to the development of these sciences and their fruitful spread all around the World, along the commercial paths of Portugal, which become also the missionary paths for the Jesuits. The books of Clavius were translated into Chinese, by one of his students Matteo Ricci "Li Madou" (1562-1610), and his influence for the development of science in China was crucial. The Jesuits become skilled astronomers, cartographers and mathematicians thanks to the example and the impulse given by Clavius. This success was possible also thanks to the contribution of Clavius in the definition of the Ratio Studiorum, the program of studies, in the Jesuit colleges, so influential for the whole history of modern Europe and all western World.

  20. Ancient Astronomical Monuments of Athens

    Science.gov (United States)

    Theodossiou, E.; Manimanis, V. N.

    2010-07-01

    In this work, four ancient monuments of astronomical significance found in Athens and still kept in the same city in good condition are presented. The first one is the conical sundial on the southern slope of the Acropolis. The second one is the Tower of the Winds and its vertical sundials in the Roman Forum of Athens, a small octagonal marble tower with sundials on all 8 of its sides, plus a water-clock inside the tower. The third monument-instrument is the ancient clepsydra of Athens, one of the findings from the Ancient Agora of Athens, a unique water-clock dated from 400 B.C. Finally, the fourth one is the carved ancient Athenian calendar over the main entrance of the small Byzantine temple of the 8th Century, St. Eleftherios, located to the south of the temple of the Annunciation of Virgin Mary, the modern Cathedral of the city of Athens.

  1. Detecting bimodality in astronomical datasets

    CERN Document Server

    Ashman, K M; Zepf, S E; Keith M Ashman; Christina M Bird; Steven E Zepf

    1994-01-01

    We discuss statistical techniques for detecting and quantifying bimodality in astronomical datasets. We concentrate on the KMM algorithm, which estimates the statistical significance of bimodality in such datasets and objectively partitions data into sub-populations. By simulating bimodal distributions with a range of properties we investigate the sensitivity of KMM to datasets with varying characteristics. Our results facilitate the planning of optimal observing strategies for systems where bimodality is suspected. Mixture-modeling algorithms similar to the KMM algorithm have been used in previous studies to partition the stellar population of the Milky Way into subsystems. We illustrate the broad applicability of KMM by analysing published data on globular cluster metallicity distributions, velocity distributions of galaxies in clusters, and burst durations of gamma-ray sources. PostScript versions of the tables and figures, as well as FORTRAN code for KMM and instructions for its use, are available by anon...

  2. Astronomical arguments in Newton's Chronology

    CERN Document Server

    Naze, Yael

    2012-01-01

    In his Chronology, Newton uses astronomical "evidence" to support its extreme rejuvenation of ancient times. These elements, having a scientific varnish, provide some credibility to the work. They have been fiercely debated for a century, with a gradual undermining of Newton's assumptions. However, this has not dented the prestige of the English scientist. ----- Dans sa Chronologie, Newton utilise des "preuves" astronomiques pour appuyer son rajeunissement extreme des epoques anciennes. Ces elements, au vernis scientifique, donnent une credibilite certaine a l'ensemble. Ils ont donc ete aprement discutes, les debats sapant petit a petit les hypotheses du savant anglais pour finalement porter un coup mortel a l'ensemble. Cela n'a toutefois pas entame le prestige du savant anglais.

  3. The prophylactic effect of neck irradiation combined with intra-oral electron beam irradiation for early tongue cancer

    International Nuclear Information System (INIS)

    Between 1967 and 1988, 102 patients with Stage T1-2N0 squamous cell carcinoma of the tongue were treated with uneven fractional irradiation therapy (intra-oral electron beam irradiation with and without prophylactic ipsilateral upper neck irradiation at the Dept. of Radiology, Nihon University School of Medicine. Of 102 primary lesions, 89 cases were controlled with this therapy. In this study, these 89 cases were investigated in order to analyze the prophylactic effect of upper neck irradiation. Of the 89 patients, 42 received only intra-oral electron beam irradiation, while the remaining 47 received a combination of intra-oral electron beam irradiation and prophylactic irradiation to the ipsilateral upper neck. Twenty three of the 89 (25.8%) developed metastasis to the neck after the radiotherapy. A breakdown of these 23 cases reveals that 3/21 (14.3%) received 40-50 Gy to the neck, 9/26 (34.6%) received 20-40 Gy to the neck, and 11/42 (26.2%) received no irradiation to the neck (p<0.05 between first and second groups, and between first and third groups). The neck metastasis was classified into one of three categories based on the region in which it first appeared (ipsilateral upper neck, ipsilateral lower neck or contralateral neck). The first metastasis was seen in the ipsilateral upper neck, in the ipsilateral lower neck and in the contralateral neck in 17, 4 and 2 patients, respectively. In 1/19 who had received 40-50 Gy, in 5/21 who had received 20-40 Gy and in 11/42 who had not received neck irradiation the first metastasis appeared in the ipsilateral upper neck. The five year survival rate was 94%, 75% and 85% in the patients receiving 40-50 Gy, 20-40 Gy and no neck irradiation, respectively. These results suggest that prophylactic irradiation of 40-50 Gy to the ipsilateral upper neck might decrease the incidence of neck metastasis and slightly prolong survival time. (author)

  4. Astronomical Data in Undergraduate courses

    Science.gov (United States)

    Clarkson, William I.; Swift, Carrie; Hughes, Kelli; Burke, Christopher J. F.; Burgess, Colin C.; Elrod, Aunna V.; Howard, Brittany; Stahl, Lucas; Matzke, David; Bord, Donald J.

    2016-06-01

    We present status and plans for our ongoing efforts to develop data analysis and problem-solving skills through Undergraduate Astronomy instruction. While our initiatives were developed with UM-Dearborn’s student body primarily in mind, they should be applicable for a wide range of institution and of student demographics. We focus here on two strands of our effort.Firstly, students in our Introductory Astronomy (ASTR 130) general-education course now perform several “Data Investigations”, in which they interrogate the Hubble Legacy Archive to illustrate important course concepts. This was motivated in part by the realization that typical public data archives now include tools to interrogate the observations that are sufficiently accessible that introductory astronomy students can use them to perform real science, albeit mostly at a descriptive level. We are continuing to refine these investigations, and, most importantly, to critically assess their effectiveness in terms of the student learning outcomes we wish to achieve. This work is supported by grant HST-EO-13758, provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.Secondly, at the advanced-undergraduate level, students taking courses in our Astronomy minor are encouraged to gain early experience in techniques of astronomical observation and analysis that are used by professionals. We present two example projects from the Fall 2015 iteration of our upper-division course ASTR330 (The Cosmic Distance Ladder), one involving Solar System measurements, the second producing calibrated aperture photometry. For both projects students conducted, analysed, and interpreted observations using our 0.4m campus telescope, and used many of the same analysis tools as professional astronomers. This work is supported partly from a Research Initiation and Seed grant from the

  5. COMMISSION 5: Documentation and Astronomical Data

    Science.gov (United States)

    Genova, Françoise; Norris, Raymond P.; Bessel, M. S.; Dluzhnevskaia, O.; Jenkner, H.; Malkov, O.; Murtagh, F.; Nakajima, K.; Ochsenbein, F.; Pence, W.; Schmitz, M.; Wielen, R.; Zhao, Y. H.

    2007-03-01

    The triennial report of Commission V Documentation and Astronomical Data/Documentation et Données Astronomiques covers 2002-2005 activities, and in particular the activities of the five Working Groups: Working Group Astronomical Data; Working Group Designations; Working Group Libraries; Working Group FITS; Working Group Virtual Observatories; and of Task Force for the Preservation and Digitization of Photographic Plates.

  6. Novel Algorithms for Astronomical Plate Analyses

    Indian Academy of Sciences (India)

    Rene Hudec; Lukas Hudec

    2011-03-01

    Powerful computers and dedicated software allow effective data mining and scientific analyses in astronomical plate archives. We give and discuss examples of newly developed algorithms for astronomical plate analyses, e.g., searches for optical transients, as well as for major spectral and brightness changes.

  7. Conceptual Astronomy Knowledge among Amateur Astronomers

    Science.gov (United States)

    Berendsen, Margaret L.

    2005-01-01

    Amateur astronomers regularly serve as informal astronomy educators for their communities. This research inquires into the level of knowledge of basic astronomy concepts among amateur astronomers and examines factors related to amateur astronomy that affect that knowledge. Using the concept questions from the Astronomy Diagnostic Test Version 2,…

  8. Current trends in laser fusion driver and beam combination laser systems using stimulated Brillouin scattering phase conjugate mirrors for a fusion driver

    International Nuclear Information System (INIS)

    Laser facilities in the world have been developing flash-lamp-pumped ultrahigh-energy solid-state lasers for fusion research and high-repetition diode-pumped solid-state lasers to act as commercial fusion drivers. A commercial laser fusion driver requires a high-energy beam with a total energy of several megajoules per pulse in several nanoseconds with a ∼10-Hz repetition rate. However, current laser technologies have limitations in raising the beam energy when operating with a high repetition rate, which is necessary for a commercial fusion driver to function properly. The beam combination laser system, which that uses stimulated Brillouin scattering phase conjugate mirrors, is a promising candidate for a fusion driver because it can obtain both a high energy and a high repetition rate with separate amplifications. For the realization of the beam combination laser system, a self-phase control technique was proposed for the coherent beam combined output, and its principle was demonstrated experimentally.

  9. A SURVEY OF ASTRONOMICAL RESEARCH: A BASELINE FOR ASTRONOMICAL DEVELOPMENT

    International Nuclear Information System (INIS)

    Measuring scientific development is a difficult task. Different metrics have been put forward to evaluate scientific development; in this paper we explore a metric that uses the number of peer-reviewed, and when available non-peer-reviewed, research articles as an indicator of development in the field of astronomy. We analyzed the available publication record, using the Smithsonian Astrophysical Observatory/NASA Astrophysics Database System, by country affiliation in the time span between 1950 and 2011 for countries with a gross national income of less than 14,365 USD in 2010. This represents 149 countries. We propose that this metric identifies countries in ''astronomical development'' with a culture of research publishing. We also propose that for a country to develop in astronomy, it should invest in outside expert visits, send its staff abroad to study, and establish a culture of scientific publishing. Furthermore, we propose that this paper may be used as a baseline to measure the success of major international projects, such as the International Year of Astronomy 2009

  10. Astronomers Gain Clues About Fundamental Physics

    Science.gov (United States)

    2005-12-01

    An international team of astronomers has looked at something very big -- a distant galaxy -- to study the behavior of things very small -- atoms and molecules -- to gain vital clues about the fundamental nature of our entire Universe. The team used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to test whether the laws of nature have changed over vast spans of cosmic time. The Green Bank Telescope The Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF (Click on image for GBT gallery) "The fundamental constants of physics are expected to remain fixed across space and time; that's why they're called constants! Now, however, new theoretical models for the basic structure of matter indicate that they may change. We're testing these predictions." said Nissim Kanekar, an astronomer at the National Radio Astronomy Observatory (NRAO), in Socorro, New Mexico. So far, the scientists' measurements show no change in the constants. "We've put the most stringent limits yet on some changes in these constants, but that's not the end of the story," said Christopher Carilli, another NRAO astronomer. "This is the exciting frontier where astronomy meets particle physics," Carilli explained. The research can help answer fundamental questions about whether the basic components of matter are tiny particles or tiny vibrating strings, how many dimensions the Universe has, and the nature of "dark energy." The astronomers were looking for changes in two quantities: the ratio of the masses of the electron and the proton, and a number physicists call the fine structure constant, a combination of the electron charge, the speed of light and the Planck constant. These values, considered fundamental physical constants, once were "taken as time independent, with values given once and forever" said German particle physicist Christof Wetterich. However, Wetterich explained, "the viewpoint of modern particle theory has changed in recent years," with ideas such as

  11. Combined brachytherapy and external beam radiotherapy without adjuvant androgen deprivation therapy for high-risk prostate cancer

    International Nuclear Information System (INIS)

    To report the outcomes of patients treated with combined iodine-125 (I-125) brachytherapy and external beam radiotherapy (EBRT) for high-risk prostate cancer. Between 2003 and 2009, I-125 permanent prostate brachytherapy plus EBRT was performed for 206 patients with high-risk prostate cancer. High-risk patients had prostate-specific antigen ≥ 20 ng/mL, and/or Gleason score ≥ 8, and/or Stage ≥ T3. One hundred and one patients (49.0%) received neoadjuvant androgen deprivation therapy (ADT) but none were given adjuvant ADT. Biochemical failure-free survival (BFFS) was determined using the Phoenix definition. The 5-year actuarial BFFS rate was 84.8%. The 5-year cause-specific survival and overall survival rates were 98.7% and 97.6%, respectively. There were 8 deaths (3.9%), of which 2 were due to prostate cancer. On multivariate analysis, positive biopsy core rates and the number of high-risk factors were independent predictors of BFFS. The 5-year BFFS rates for patients in the positive biopsy core rate <50% and ≥50% groups were 89.3% and 78.2%, respectively (p = 0.03). The 5-year BFFS rate for patients with the any single high-risk factor was 86.1%, compared with 73.6% for those with any 2 or all 3 high-risk factors (p = 0.03). Neoadjuvant ADT did not impact the 5-year BFFS. At a median follow-up of 60 months, high-risk prostate cancer patients undergoing combined I-125 brachytherapy and EBRT without adjuvant ADT have a high probability of achieving 5-year BFFS

  12. Application of Electron-Beam Irradiation Combined with Aging for Improvement of Microbiological and Physicochemical Quality of Beef Loin

    Science.gov (United States)

    Yim, Dong-Gyun; Jo, Cheorun

    2016-01-01

    The combined effects of irradiation and aging temperature on the microbial and chemical quality of beef loin were investigated. The samples were vacuum-packaged, irradiated at 0 or 2 kGy using electron-beam (EB), and stored for 10 d at different aging temperatures (2, 14, or 25℃). The microbial growth, shear values, meat color, and nucleotide-related flavor compounds of the samples were analyzed. The irradiation effect on inactivation of foodborne pathogens was also investigated. The population of Listeria monocytogenes and Escherhia coli O157:H7 inoculated in beef samples decreased in proportion to the irradiation dose. Irradiation reduced the total aerobic bacteria (TAB) over the storage, but higher aging temperature increased the TBA. Thus TAB increased sharply in non-irradiated and high temperature-aged (14, 25℃) beef samples after 5 d. With increasing aging temperature and aging time, shear force values decreased. Lipid oxidation could be reduced by short aging time at low aging temperature. The color a* values of the irradiated beef were lower than those of the non-irradiated throughout the aging period. As aging period and temperature increased, IMP decreased and hypoxanthine increased. Considering microbial and physicochemical properties, irradiation can be used for raw beef to be aged at relatively high temperature to shorten aging time and cost. PMID:27194930

  13. Combined reactor neutron beam and {sup 60}Co γ-ray radiation effects on CMOS APS image sensors

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zujun, E-mail: wangzujun@nint.ac.cn; Chen, Wei; Sheng, Jiangkun; Liu, Yan; Xiao, Zhigang; Huang, Shaoyan; Liu, Minbo [State Key Laboratory of Intense Pulsed Radiation Simulation and Effect, Northwest Institute of Nuclear Technology, P.O.Box 69-10, Xi’an, Shaanxi 710024 China (China)

    2015-02-15

    The combined reactor neutron beam and {sup 60}Co γ-ray radiation effects on complementary metal-oxide semiconductor (CMOS) active pixel sensors (APS) have been discussed and some new experimental phenomena are presented. The samples are manufactured in the standard 0.35-μm CMOS technology. Two samples were first exposed to {sup 60}Co γ-rays up to the total ionizing dose (TID) level of 200 krad(Si) at the dose rates of 50.0 and 0.2 rad(Si)/s, and then exposed to neutron fluence up to 1 × 10{sup 11} n/cm{sup 2} (1-MeV equivalent neutron fluence). One sample was first exposed to neutron fluence up to 1 × 10{sup 11} n/cm{sup 2} (1-MeV equivalent neutron fluence), and then exposed to {sup 60}Co γ-rays up to the TID level of 200 krad(Si) at the dose rate of 0.2 rad(Si)/s. The mean dark signal (K{sub D}), the dark signal non-uniformity (DSNU), and the noise (V{sub N}) versus the total dose and neutron fluence has been investigated. The degradation mechanisms of CMOS APS image sensors have been analyzed, especially for the interaction induced by neutron displacement damage and TID damage.

  14. Combined reactor neutron beam and 60Co γ-ray radiation effects on CMOS APS image sensors

    Directory of Open Access Journals (Sweden)

    Zujun Wang

    2015-02-01

    Full Text Available The combined reactor neutron beam and 60Co γ-ray radiation effects on complementary metal-oxide semiconductor (CMOS active pixel sensors (APS have been discussed and some new experimental phenomena are presented. The samples are manufactured in the standard 0.35-μm CMOS technology. Two samples were first exposed to 60Co γ-rays up to the total ionizing dose (TID level of 200 krad(Si at the dose rates of 50.0 and 0.2 rad(Si/s, and then exposed to neutron fluence up to 1 × 1011 n/cm2 (1-MeV equivalent neutron fluence. One sample was first exposed to neutron fluence up to 1 × 1011 n/cm2 (1-MeV equivalent neutron fluence, and then exposed to 60Co γ-rays up to the TID level of 200 krad(Si at the dose rate of 0.2 rad(Si/s. The mean dark signal (KD, the dark signal non-uniformity (DSNU, and the noise (VN versus the total dose and neutron fluence has been investigated. The degradation mechanisms of CMOS APS image sensors have been analyzed, especially for the interaction induced by neutron displacement damage and TID damage.

  15. Combined reactor neutron beam and 60Co γ-ray radiation effects on CMOS APS image sensors

    International Nuclear Information System (INIS)

    The combined reactor neutron beam and 60Co γ-ray radiation effects on complementary metal-oxide semiconductor (CMOS) active pixel sensors (APS) have been discussed and some new experimental phenomena are presented. The samples are manufactured in the standard 0.35-μm CMOS technology. Two samples were first exposed to 60Co γ-rays up to the total ionizing dose (TID) level of 200 krad(Si) at the dose rates of 50.0 and 0.2 rad(Si)/s, and then exposed to neutron fluence up to 1 × 1011 n/cm2 (1-MeV equivalent neutron fluence). One sample was first exposed to neutron fluence up to 1 × 1011 n/cm2 (1-MeV equivalent neutron fluence), and then exposed to 60Co γ-rays up to the TID level of 200 krad(Si) at the dose rate of 0.2 rad(Si)/s. The mean dark signal (KD), the dark signal non-uniformity (DSNU), and the noise (VN) versus the total dose and neutron fluence has been investigated. The degradation mechanisms of CMOS APS image sensors have been analyzed, especially for the interaction induced by neutron displacement damage and TID damage

  16. The Optical/Infrared Astronomical Quality of High Atacama Sites. I. Preliminary Results of Optical Seeing

    OpenAIRE

    Giovanelli, Riccardo; Darling, Jeremy; Sarazin, Marc; Yu, Jennifer; Harvey, Paul; Henderson, Charles; Hoffman, William; Keller, Luke; Barry, Don; Cordes, James; Eikenberry, Stephen; Gull, George; Harrington, Joseph; Smith, J D; Stacey, Gordon

    2001-01-01

    The region surrounding the Llano de Chajnantor, a high altitude plateau in the Atacama Desert in northern Chile, has caught the attention of the astronomical community for its potential as an observatory site. Combining high elevation and extremely low atmospheric water content, the Llano has been chosen as the future site of the Atacama Large Millimeter Array. We have initiated a campaign to investigate the astronomical potential of the region in the optical/infrared. Here, we report on an a...

  17. Young Galaxy's Magnetism Surprises Astronomers

    Science.gov (United States)

    2008-10-01

    Astronomers have made the first direct measurement of the magnetic field in a young, distant galaxy, and the result is a big surprise. Looking at a faraway protogalaxy seen as it was 6.5 billion years ago, the scientists measured a magnetic field at least 10 times stronger than that of our own Milky Way. They had expected just the opposite. The GBT Robert C. Byrd Green Bank Telescope CREDIT: NRAO/AUI/NSF The scientists made the discovery using the National Science Foundation's ultra-sensitive Robert C. Byrd Green Bank Telescope (GBT) in West Virginia. "This new measurement indicates that magnetic fields may play a more important role in the formation and evolution of galaxies than we have realized," said Arthur Wolfe, of the University of California-San Diego (UCSD). At its great distance, the protogalaxy is seen as it was when the Universe was about half its current age. According to the leading theory, cosmic magnetic fields are generated by the dynamos of rotating galaxies -- a process that would produce stronger fields with the passage of time. In this scenario, the magnetic fields should be weaker in the earlier Universe, not stronger. The new, direct magnetic-field measurement comes on the heels of a July report by Swiss and American astronomers who made indirect measurements that also implied strong magnetic fields in the early Universe. "Our results present a challenge to the dynamo model, but they do not rule it out," Wolfe said. There are other possible explanations for the strong magnetic field seen in the one protogalaxy Wolfe's team studied. "We may be seeing the field close to the central region of a massive galaxy, and we know such fields are stronger toward the centers of nearby galaxies. Also, the field we see may have been amplified by a shock wave caused by the collision of two galaxies," he said. The protogalaxy studied with the GBT, called DLA-3C286, consists of gas with little or no star formation occurring in it. The astronomers suspect that

  18. Effects of a 2-step culture with cytokine combinations on megakaryocytopoiesis and thrombopoiesis from carbon-ion beam-irradiated human hematopoietic stem/progenitor cells

    International Nuclear Information System (INIS)

    To evaluate whether the continuous treatment of two cytokine combinations is effective in megakaryocytopoiesis and thrombopoiesis in hematopoietic stem/progenitor cells exposed to heavy ion beams, the effects of a 2-step culture by a combination of recombinant human interleukin-3 (IL-3)+stem cell factor (SCF)+thrombopoietin (TPO), which just slightly protected against carbon-ion beam-induced damages, and a combination of IL-3+TPO, which selectively stimulated the differentiation of the hematopoietic stem/progenitor cells to megakaryocytes and platelets, were examined. CD34+-hematopoietic stem/progenitor cells isolated from the human placental and umbilical cord blood were exposed to carbon-ion beams (linear energy transfer (LET)=50 keV/μm) at 2 Gy. These cells were cultured under three cytokine conditions. The number of megakaryocytes, platelets and hematopoietic progenitors were assessed using a flow cytometer and a clonogenic assay at 14 and 21 days after irradiation, respectively. However, the efficacy of each 2-step culture was equal or lower than that of using the IL-3+SCF+TPO combination alone and the 2-step culture could not induce megakaryocytes and platelets from hematopoietic stem/progenitor cells exposed to high LET-radiation such as carbon-ion beams. Therefore, additional cytokines and/or hematopoietic promoting compounds might be required to overcome damage to hematopoietic cells by high LET radiation. (author)

  19. Comparison of treatment using teletherapy (external beam radiation) alone versus teletherapy combined with brachytherapy for advanced squamous cell carcinoma of the esophagus

    Energy Technology Data Exchange (ETDEWEB)

    Samea, Renato; Lourenco, Laercio Gomes, E-mail: renatosamea@globo.com [Department of Surgical Oncology of Dr. Arnaldo Vieira de Carvalho Hospital, Sao Paulo, SP (Brazil)

    2011-10-15

    Background - Squamous cell carcinoma of the esophagus is still a difficult tumor to treat with very poor prognosis. Aim - To compare the response to teletherapy treatment (external beam radiotherapy) alone versus teletherapy combined with brachytherapy for patients with advanced squamous cell carcinoma of the esophagus. Methods - Were studied 49 patients with advanced squamous cell carcinoma of the esophagus on clinical stage III (TNM-1999). They were separated into two groups. The first, underwent radiation therapy alone with linear accelerator of particles, average dose of 6000 cGy and the second to external beam radiation therapy at a dose of 5040 cGy combined with brachytherapy with Iridium 192 at a dose of 1500 cGy. Brachytherapy started one to two weeks after the end of teletherapy, and it was divided into three weekly applications of 500 cGy. Age, gender, race, habits (smoking and drinking), body mass index (BMI), complications with treatment benefits (pain relief and food satisfaction) and survival were analyzed. Results - The quality of life (food satisfaction, and pain palliation of dysphagia) were better in the group treated with external beam radiation therapy combined with brachytherapy. Survival was higher in the brachytherapy combined with external beam radiation therapy alone. Conclusion - Although the cure rate of squamous cell cancer of the esophagus is almost nil when treated with irradiation alone, this therapy is a form of palliative treatment for most patients in whom surgical contraindication exists. (author)

  20. Leveraging Data Lineage to Infer Logical Relationships between Astronomical Catalogs

    CERN Document Server

    Buddelmeijer, Hugo

    2012-01-01

    A novel method to infer logical relationships between sets is presented. These sets can be any collection of elements, for example astronomical catalogs of celestial objects. The method does not require the contents of the sets to be known explicitly. It combines incomplete knowledge about the relationships between sets to infer a priori unknown relationships. Relationships between sets are represented by sets of Boolean hypercubes. This leads to deductive reasoning by application of logical operators to these sets of hypercubes. A pseudocode for an efficient implementation is described. The method is used in the Astro-WISE information system to infer relationships between catalogs of astronomical objects. These catalogs can be very large and, more importantly, their contents do not have to be available at all times. Science products are stored in Astro-WISE with references to other science products from which they are derived, or their dependencies. This creates full data lineage that links every science pro...

  1. Astronomical surveys and big data

    Science.gov (United States)

    Mickaelian, Areg M.

    Recent all-sky and large-area astronomical surveys and their catalogued data over the whole range of electromagnetic spectrum, from γ -rays to radio waves, are reviewed, including such as Fermi-GLAST and INTEGRAL in γ -ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and POSS II-based catalogues (APM, MAPS, USNO, GSC) in the optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio range, and many others, as well as the most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS), and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). An overall understanding of the coverage along the whole wavelength range and comparisons between various surveys are given: galaxy redshift surveys, QSO/AGN, radio, Galactic structure, and Dark Energy surveys. Astronomy has entered the Big Data era, with Astrophysical Virtual Observatories and Computational Astrophysics playing an important role in using and analyzing big data for new discoveries.

  2. Astronomical Knowledge in Holy Books

    Science.gov (United States)

    Farmanyan, Sona V.; Mickaelian, Areg M.

    2015-08-01

    We investigate religious myths related to astronomy from different cultures in an attempt to identify common subjects and characteristics. The paper focuses on astronomy in religion. The initial review covers records from Holy books about sky related superstitious beliefs and cosmological understanding. The purpose of this study is to introduce sky related religious and national traditions (particularly based on different calendars; Solar or Lunar). We carried out a comparative study of astronomical issues contained in a number of Holy books: Ancient Egyptian Religion (Pyramid Texts), Zoroastrianism (Avesta), Hinduism (Vedas), Buddhism (Tipitaka), Confucianism (Five Classics), Sikhism (Guru Granth Sahib), Christianity (Bible), Islam (Quran), Druidism (Mabinogion) and Maya Religion (Popol Vuh). These books include various information on the creation of the Universe, Sun and Moon, the age of the Universe, Cosmic sizes, understanding about the planets, stars, Milky Way and description of the Heavens in different religions. We come to the conclusion that the perception of celestial objects varies from culture to culture, and from religion to religion and preastronomical views had a significant impact on humankind, particularly on religious diversities. We prove that Astronomy is the basis of cultures, and that national identity and mythology and religion were formed due to the special understanding of celestial objects.

  3. A Future Astronomical Software Environment

    Science.gov (United States)

    Grosböl, P.; Tody, D.; Paioro, L.; Granet, Y.; Garilli, B.; Surace, C.; Opticon Fase Network

    2012-09-01

    Analyzing data sets in astronomy has become more and more complex and has driven the development of specific tools, functions and tasks. In order to integrate these tools in a global environment and thereby preserving them, the OPTICON Network 9.2 in coordination with US-VAO has outlined requirements, defined an architectural concept and developed a prototype of a Future Astronomical Software Environment (FASE). Important features are support for user scripting (e.g. Python), access to legacy applications (e.g. IRAF, MIDAS), integration with the Virtual Observatory (VO) for access to remote data and computation, and scalability supporting desktops to distributed cluster systems. A first prototype has been implemented and demonstrates the feasibility by offering access to numerous applications (e.g. ds9, ESO CPL pipelines, MIDAS, topcat) from a Python or Unix shell using VO-SAMP as a software bus. A simple packaging system is also provided to allow easy definition and sharing of applications at a Web portal.

  4. Astronomical Surveys and Big Data

    CERN Document Server

    Mickaelian, A M

    2015-01-01

    Recent all-sky and large-area astronomical surveys and their catalogued data over the whole range of electromagnetic spectrum are reviewed, from Gamma-ray to radio, such as Fermi-GLAST and INTEGRAL in Gamma-ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and II based catalogues (APM, MAPS, USNO, GSC) in optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio and many others, as well as most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS) and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). An overall understanding of the coverage along the whole wavelength range and comparisons between various surveys are given: galaxy redshift surveys, QSO/AGN, radio, Galactic structure, and Dark Energy surveys. Astronomy has entered the Big Data era. Astrophysical Virtual Observatories and Computational Astrophysics play a...

  5. Theoretical explanation of the polarization-converting system achieved by beam shaping and combination technique and its performance under high power conditions

    Science.gov (United States)

    Wang, Peng; Li, Xiao; Shang, YaPing; Xu, XiaoJun

    2015-10-01

    The fiber laser has very obvious advantages and broad applications in remote welding, 3D cutting and national defense compared with the traditional solid laser. But influenced by heat effect of gain medium, nonlinear effect, stress birefringence effect and other negative factors, it's very difficult to get high power linearly polarized laser just using a single laser. For these limitations a polarization-converting system is designed using beam shaping and combination technique which is able to transform naturally polarized laser to linearly polarized laser at real time to resolve difficulties of generating high-power linearly polarized laser from fiber lasers in this paper. The principle of the Gaussian beam changing into the hollow beam passing through two axicons and the combination of the Gaussian beam and the hollow beam is discussed. In the experimental verification the energy conversion efficiency reached 93.1% with a remarkable enhancement of the extinction ratio from 3% to 98% benefited from the high conversion efficiency of axicons and the system worked fine under high power conditions. The system also kept excellent far field divergence. The experiment phenomenon also agreed with the simulation quite well. The experiment proves that this polarization-converting system will not affect laser structure which controls easily and needs no feedback and controlling system with stable and reliable properties at the same time. It can absolutely be applied to the polarization-conversion of high power laser.

  6. Franklin Edward Kameny (1925-2011, Astronomer)

    Science.gov (United States)

    Wright, Jason

    2012-01-01

    Dr. Frank Kameny is best known today as one of the most important members of the gay rights movement in the United States, but he was also a PhD astronomer. In fact, it was his firing from his civil service position as astronomer for the US Army Map Service on the grounds of homosexuality that sparked his lifelong career of activism. Here, I explore some aspects of his short but interesting astronomical career and the role of the AAS in his life.

  7. SU-E-J-181: Effect of Prostate Motion On Combined Brachytherapy and External Beam Dose Based On Daily Motion of the Prostate

    Energy Technology Data Exchange (ETDEWEB)

    Narayana, V; McLaughlin, P [Providence Cancer Center, Southfield, MI (United States); University of Michigan, Ann Arbor, MI (United States); Ealbaj, J [University of Michigan, Ann Arbor, MI (United States)

    2015-06-15

    Purpose: In this study, the adequacy of target expansions on the combined external beam and implant dose was examined based on the measured daily motion of the prostate. Methods: Thirty patients received an I–125 prostate implant prescribed to dose of 90Gy. This was followed by external beam to deliver a dose of 90Gyeq (external beam equivalent) to the prostate over 25 to 30 fractions. An ideal IMRT plan was developed by optimizing the external beam dose based on the delivered implant dose. The implant dose was converted to an equivalent external beam dose using the linear quadratic model. Patients were set up on the treatment table by daily orthogonal imaging and aligning the marker seeds in the prostate. Orthogonal images were obtained at the end of treatment to assess prostate intrafraction motion. Based on the observed motion of the markers between the initial and final images, 5 individual plans showing the actual dose delivered to the patient were calculated. A final true dose distribution was established based on summing the implant dose and the 5 external beam plans. Dose to the prostate, seminal vesicles, lymphnodes and normal tissues, rectal wall, urethra and lower sphincter were calculated and compared to ideal. On 18 patients who were sexually active, dose to the corpus cavernosum and internal pudendal artery was also calculated. Results: The average prostate motion in 3 orthogonal directions was less than 1 mm with a standard deviation of less than +2 mm. Dose and volume parameters showed that there was no decrease in dose to the targets and a marginal decrease in dose to in normal tissues. Conclusion: Dose delivered by seed implant moves with the prostate, decreasing the impact of intrafractions dose movement on actual dose delivered. Combined brachytherapy and external beam dose delivered to the prostate was not sensitive to prostate motion.

  8. Multidimensional characterisation of biomechanical structures by combining Atomic Force Microscopy and Focused Ion Beam: A study of the rat whisker.

    Science.gov (United States)

    Adineh, Vahid Reza; Liu, Boyin; Rajan, Ramesh; Yan, Wenyi; Fu, Jing

    2015-07-01

    Understanding the heterogeneity of biological structures, particularly at the micro/nano scale can offer insights valuable for multidisciplinary research in tissue engineering and biomimicry designs. Here we propose to combine nanocharacterisation tools, particularly Focused Ion Beam (FIB) and Atomic Force Microscopy (AFM) for three dimensional mapping of mechanical modulus and chemical signatures. The prototype platform is applied to image and investigate the fundamental mechanics of the rat face whiskers, a high-acuity sensor used to gain detailed information about the world. Grazing angle FIB milling was first applied to expose the interior cross section of the rat whisker sample, followed by a "lift-out" method to retrieve and position the target sample for further analyses. AFM force spectroscopy measurements revealed a non-uniform pattern of elastic modulus across the cross section, with a range from 0.8GPa to 13.5GPa. The highest elastic modulus was found at the outer cuticle region of the whisker, and values gradually decreased towards the interior cortex and medulla regions. Elemental mapping with EDS confirmed that the interior of the rat whisker is dominated by C, O, N, S, Cl and K, with a significant change of elemental distribution close to the exterior cuticle region. Based on these data, a novel comprehensive three dimensional (3D) elastic modulus model was constructed, and stress distributions under realistic conditions were investigated with Finite Element Analysis (FEA). The simulations could well account for the passive whisker deflections, with calculated resonant frequency as well as force-deflection for the whiskers being in good agreement with reported experimental data. Limitations and further applications are discussed for the proposed FIB/AFM approach, which holds good promise as a unique platform to gain insights on various heterogeneous biomaterials and biomechanical systems. PMID:25839121

  9. Astronomers no longer in the dark

    CERN Multimedia

    MacMillan, L

    2002-01-01

    In a significant breakthrough, British and US astronomers have begun to pin down the most elusive material in the universe. They have made a map of dark matter - the heavy, invisible stuff that gives the galaxies their shape (1 page).

  10. Astronomers find distant planet like Jupiter

    CERN Multimedia

    2003-01-01

    Astronomers searching for planetary systems like our solar system have found a planet similar to Jupiter orbiting a nearby star similar to our Sun, about 90 light-years from Earth, according to researchers (1/2 page).

  11. Longwave Imaging for Astronomical Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a compact portable longwave camera for astronomical applications. In Phase 1, we successfully developed the eye of the camera, i.e. the focal...

  12. Astronomical data bases and retrieval systems

    Science.gov (United States)

    Mead, J. M.; Nagy, T. A.; Warren, W. H., Jr.

    1981-01-01

    The status of the development of machine-readable stellar and extragalactic data bases is summarized, including several examples of astronomical applications using these data sets. The creation of a computerized bibliographical data base for cometary research is described.

  13. Longwave Imaging for Astronomical Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a compact portable longwave camera for astronomical applications. In Phase 1, we will develop and deliver the focal plane array (FPA) - a...

  14. Astronomers Unveiling Life's Cosmic Origins

    Science.gov (United States)

    2009-02-01

    Processes that laid the foundation for life on Earth -- star and planet formation and the production of complex organic molecules in interstellar space -- are yielding their secrets to astronomers armed with powerful new research tools, and even better tools soon will be available. Astronomers described three important developments at a symposium on the "Cosmic Cradle of Life" at the annual meeting of the American Association for the Advancement of Science in Chicago, IL. Chemistry Cycle The Cosmic Chemistry Cycle CREDIT: Bill Saxton, NRAO/AUI/NSF Full Size Image Files Chemical Cycle Graphic (above image, JPEG, 129K) Graphic With Text Blocks (JPEG, 165K) High-Res TIFF (44.2M) High-Res TIFF With Text Blocks (44.2M) In one development, a team of astrochemists released a major new resource for seeking complex interstellar molecules that are the precursors to life. The chemical data released by Anthony Remijan of the National Radio Astronomy Observatory (NRAO) and his university colleagues is part of the Prebiotic Interstellar Molecule Survey, or PRIMOS, a project studying a star-forming region near the center of our Milky Way Galaxy. PRIMOS is an effort of the National Science Foundation's Center for Chemistry of the Universe, started at the University of Virginia (UVa) in October 2008, and led by UVa Professor Brooks H. Pate. The data, produced by the NSF's Robert C. Byrd Green Bank Telescope (GBT) in West Virginia, came from more than 45 individual observations totalling more than nine GigaBytes of data and over 1.4 million individual frequency channels. Scientists can search the GBT data for specific radio frequencies, called spectral lines -- telltale "fingerprints" -- naturally emitted by molecules in interstellar space. "We've identified more than 720 spectral lines in this collection, and about 240 of those are from unknown molecules," Remijan said. He added, "We're making available to all scientists the best collection of data below 50 GHz ever produced for

  15. Publication and citation statistics for UK astronomers

    CERN Document Server

    Blustin, A J

    2007-01-01

    This article presents a survey of publication and citation statistics for 835 UK professional astronomers: the majority of academics and contract researchers within the UK astronomical community. I provide histograms of these bibliometrics for the whole sample as well as of the median values for the individual departments. I discuss the distribution of top bibliometric performers in the sample, and make some remarks on the usage of bibliometrics in a real-world assessment exercise.

  16. Bayesian mixture models for Poisson astronomical images

    OpenAIRE

    Guglielmetti, Fabrizia; Fischer, Rainer; Dose, Volker

    2012-01-01

    Astronomical images in the Poisson regime are typically characterized by a spatially varying cosmic background, large variety of source morphologies and intensities, data incompleteness, steep gradients in the data, and few photon counts per pixel. The Background-Source separation technique is developed with the aim to detect faint and extended sources in astronomical images characterized by Poisson statistics. The technique employs Bayesian mixture models to reliably detect the background as...

  17. Astronomical Plate Archives and Binary Blazars Studies

    Indian Academy of Sciences (India)

    Rene Hudec

    2011-03-01

    There are about 3 million astronomical photographic plates around the globe, representing an important data source for various aspects of astrophysics. The main advantage is the large time coverage of 100 years or even more. Recent digitization efforts, together with the development of dedicated software, enables for the first time, effective data mining and data analyses by powerful computers with these archives. Examples of blazars proposed and/or investigated on the astronomical plates are presented and discussed.

  18. Combined electron-beam and coagulation purification of molasses distillery slops. Features of the method, technical and economic evaluation of large-scale facility

    International Nuclear Information System (INIS)

    The paper summarizes the results obtained from the study on combined electron-beam and coagulation method for purification of molasses distillery slops from distillery produced ethyl alcohol by fermentation of grain, potato, beet and some other plant materials. The method consists in preliminary mixing of industrial wastewater with municipal wastewater, electron-beam treatment of the mixture and subsequent coagulation. Technical and economic evaluation of large-scale facility (output of 7000 m3 day-1) with two powerful cascade electron accelerators (total maximum beam power of 400 kW) for treatment of the wastewater by the above method was carried out. It was calculated that the cost of purification of the wastes is equal to 0.25 US$ m-3 that is noticeably less than in the case of the existing method

  19. Validation of the Local Hadronic Calibration Scheme of ATLAS with Combined Beam Test Data in the End-Cap and Forward Regions of ATLAS

    CERN Document Server

    Kiryunin, A; The ATLAS collaboration

    2011-01-01

    The three Atlas calorimeter systems in the region of the forward crack at |eta| = 3.2 in the nominal Atlas setup have been exposed to combined beam tests with single electrons and pions. Detailed shower shape studies of electrons and pions with comparisons to various Geant4 based simulations utilizing different physics lists are presented. The Local Hadron Calibration developed for the energy reconstruction and the calibration of jets and missing transverse energy in ATLAS, has been validated using data obtained during these beam tests. The analysis has been carried out by using special sets of calibration weights and corrections obtained with the Geant4 simulation of a detailed beam test set-up. The validation itself has been performed by careful studying specific calorimeter performance parameters such as e.g. energy response, energy resolution, shower shapes, cluster energy density as well as different physics lists of the Geant4 simulation.

  20. Beam instability induced by rf deflectors in the combiner ring of the CLIC test facility and mitigation by damped deflecting structures

    CERN Document Server

    Alesini, D; Biscari, C; Ghigo, A; Corsini, R

    2011-01-01

    In the CTF3 (CLIC test facility 3) run of November 2007, a vertical beam instability has been found in the combiner ring during operation. After a careful analysis, the source of the instability has been identified in the vertical deflecting modes trapped in the rf deflectors and excited by the beam passage. A dedicated tracking code that includes the induced transverse wakefield and the multibunch multipassage effects has been written and the results of the beam dynamics analysis are presented in the paper. The mechanism of the instability was similar to the beam breakup in a linear accelerator or in an energy recovery linac. The results of the code allowed identifying the main key parameters driving such instability and allowed finding the main knobs to mitigate it. To completely suppress such beam instability, two new rf deflectors have been designed, constructed, and installed in the ring. In the new structures the frequency separation between the vertical and horizontal deflecting modes has been increase...

  1. Combined infrared multiphoton dissociation and electron-capture dissociation using co-linear and overlapping beams in Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Mihalca, Romulus; van der Burgt, Yuri E M; McDonnell, Liam A; Duursma, Marc; Cerjak, Iliya; Heck, Albert J R; Heeren, Ron M A

    2006-01-01

    A novel set-up for Fourier transform ion cyclotron resonance mass spectrometry (FTICR) is reported for simultaneous infrared multiphoton dissociation (IRMPD) and electron-capture dissociation (ECD). An unmodified electron gun ensures complete, on-axis overlap between the electron and the photon beams. The instrumentation, design and implementation of this novel approach are described. In this configuration the IR beam is directed into the ICR cell using a pneumatically actuated mirror inserted into the ion-optical path. Concept validation was made using different combinations of IRMPD and ECD irradiation events on two standard peptides. The ability to perform efficient IRMPD, ECD and especially simultaneous IRMPD and ECD using lower irradiation times is demonstrated. The increase in primary sequence coverage, with the combined IRMPD and ECD set-up, also increases the confidence in peptide and protein assignments. PMID:16705647

  2. Construction of a 100 m3/h demonstration plant in Bad Fischau-Brunn for groundwater remediation by a combined ozone/electron beam irradiation treatment process

    International Nuclear Information System (INIS)

    Groundwater contaminated with about 60 μg/L perchloroethylene (PCE) is purified by a combined ozone/electron beam irradiation process for subsequent use as drinking water. The design of the first commercial plant for such a groundwater remediation having a capacity of 108 m3/h is described. The mechanism of the combined ozone/electron beam process for PCE decomposition is discussed with respect to other ozone based advanced oxidation processes like ozone/U.V. and ozone/hydrogen peroxide. The formation of trace amounts of trichloroacetic acid as the only organic by-product in all these processes has been interpreted as an indication that PCE decomposition proceeds via the same mechanism in all cases. (author)

  3. Astronomers Get New Tools for Gravitational-Wave Detection

    Science.gov (United States)

    2010-01-01

    exclaimed. "Fermi showed us where to look." "This is a huge help in our effort to use millisecond pulsars to detect gravitational waves," Ransom said. The more such pulsars scientists can find and observe over time, the more likely they are to detect gravitational waves, he explained. He said that astronomers now have barely enough millisecond pulsars to make a convincing gravitational-wave detection. "With Fermi guiding the way, though, we can change that picture quickly," Ray said. "We've just started to follow up on the objects located by Fermi, and have many more to go, with a great success rate so far," he added. Ransom, along with his colleague Mallory Roberts of Eureka Scientific, used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to find eight of the 17 new pulsars. The scientists announced their discoveries at the American Astronomical Society's meeting in Washington, DC. Pulsars are neutron stars -- the dense cores left after a massive star has exploded as a supernova. About as large as a medium-sized city, these neutron stars have strong magnetic fields that channel lighthouse-like beams of radio waves that sweep through space as the star rotates. When such a beam strikes the Earth, radio telescopes can detect the strong radio waves. As they age, pulsars slow their rotation rates. However, if the pulsar is part of a binary-star system and can draw in material from its companion, its rotation can be sped up. When the neutron star has been sped up to rotate hundreds of times a second, it is called a millisecond pulsar. In addition to helping scientists detect gravitational waves, study of millisecond pulars also can yield important new information about other effects of General Relativity and about fundamental particle physics. "This new ability to find many more millisecond pulsars really is a treasure chest that can yield many valuable gems of scientific discovery," Ransom said.

  4. F.W. Longbottom: astronomical photographer and founder of the Chester Astronomical Society

    CERN Document Server

    Shears, Jeremy

    2012-01-01

    Frederick William Longbottom FRAS (1850-1933) was an original member of the British Astronomical Association and served as Director of its Photographic Section between 1906 and 1926. A hop merchant by trade, he spent much of his life in Chester where he was instrumental in founding the City's first astronomical society in 1892.

  5. SweepSAR: Beam-forming on Receive Using a Reflector-Phased Array Feed Combination for Spaceborne SAR

    Science.gov (United States)

    Freeman, A.; Krieger, G.; Rosen, P.; Younis, M.; Johnson, W. T. K.; Huber, S.; Jordan, R.; Moreira, A.

    2012-01-01

    In this paper, an alternative approach is described that is suited for longer wavelength SARs in particular, employing a large, deployable reflector antenna and a much simpler phased array feed. To illuminate a wide swath, a substantial fraction of the phased array feed is excited on transmit to sub-illuminate the reflector. Shorter transmit pulses are required than for conventional SAR. On receive, a much smaller portion of the phased array feed is used to collect the return echo, so that a greater portion of the reflector antenna area is used. The locus of the portion of the phased array used on receive is adjusted using an analog beam steering network, to 'sweep' the receive beam(s) across the illuminated swath, tracking the return echo. This is similar in some respects to the whiskbroom approach to optical sensors, hence the name: SweepSAR.SweepSAR has advantages over conventional SAR in that it requires less transmit power, and if the receive beam is narrow enough, it is relatively immune to range ambiguities. Compared to direct radiating arrays with digital beam- forming, it is much simpler to implement, uses currently available technologies, is better suited for longer wavelength systems, and does not require extremely high data rates or onboard processing.

  6. Large astronomical catalog management for telescope operations

    Science.gov (United States)

    Baruffolo, Andrea; Benacchio, Leopoldo

    1998-07-01

    Large astronomical catalogues containing from a million up to hundreds of millions records are currently available, even larger catalogues will be released in the near future. They will have an important operational role since they will be used throughout the observing cycle of next generation large telescopes, for proposal and observation preparation, telescope scheduling, selection of guide stars, etc. These large databases pose new problems for fast and general access. Solutions based on custom software or on customized versions of specific catalogues have been proposed, but the problem will benefit from a more general database approach. While traditional database technologies have proven to be inadequate for this task, new technologies are emerging, in particular that of Object Relational DBMSs, that seem to be suitable to solve the problem. In this paper we describe our experiences in experimenting with ORDBMSs for the management of large astronomical catalogues. We worked especially on the database query language and access methods. In the first field to extend the database query language capabilities with astronomical functionalities and to support typical astronomical queries.In the second, to speed up the execution of queries containing astronomical predicates.

  7. How Astronomers View Education and Public Outreach

    CERN Document Server

    Dang, Lisa

    2015-01-01

    Over the past few years, there have been a few studies on the development of an interest in science and scientists' views on public outreach. Yet, to date, there has been no global study regarding astronomers' views on these matters. Through the completion of our survey by 155 professional astronomers online and in person during the 28th International Astronomical Union General Assembly in 2012, we explored their development of and an interest for astronomy and their views on time constraints and budget restriction regarding public outreach activities. We find that astronomers develop an interest in astronomy between the ages of 4-6 but that the decision to undertake a career in astronomy often comes during late adolescence. We also discuss the claim that education and public outreach is regarded an optional task rather than a scientist's duty. Our study revealed that many astronomers think there should be a larger percentage of their research that should be invested into outreach activities, calling for a ch...

  8. Astronomical Data Integration Beyond the Virtual Observatory

    Science.gov (United States)

    Lemson, G.; Laurino, O.

    2015-09-01

    "Data integration" generally refers to the process of combining data from different source data bases into a unified view. Much work has been devoted in this area by the International Virtual Observatory Alliance (IVOA), allowing users to discover and access databases through standard protocols. However, different archives present their data through their own schemas and users must still select, filter, and combine data for each archive individually. An important reason for this is that the creation of common data models that satisfy all sub-disciplines is fraught with difficulties. Furthermore it requires a substantial amount of work for data providers to present their data according to some standard representation. We will argue that existing standards allow us to build a data integration framework that works around these problems. The particular framework requires the implementation of the IVOA Table Access Protocol (TAP) only. It uses the newly developed VO data modelling language (VO-DML) specification, which allows one to define extensible object-oriented data models using a subset of UML concepts through a simple XML serialization language. A rich mapping language allows one to describe how instances of VO-DML data models are represented by the TAP service, bridging the possible mismatch between a local archive's schema and some agreed-upon representation of the astronomical domain. In this so called local-as-view approach to data integration, “mediators" use the mapping prescriptions to translate queries phrased in terms of the common schema to the underlying TAP service. This mapping language has a graphical representation, which we expose through a web based graphical “drag-and-drop-and-connect" interface. This service allows any user to map the holdings of any TAP service to the data model(s) of choice. The mappings are defined and stored outside of the data sources themselves, which allows the interface to be used in a kind of crowd-sourcing effort

  9. Astronomers celebrate a year of new Hubble results

    Science.gov (United States)

    1995-02-01

    "We are beginning to understand that because of these observations we are going to have to change the way we look at the Universe," said ESA's Dr Duccio Macchetto, Associate Director for Science Programs at the Space Telescope Science Institute (STScI), Baltimore, Maryland, USA. The European Space Agency plays a major role in the Hubble Space Telescope programme. The Agency provided one of the telescope's four major instruments, called the Faint Object Camera, and two sets of electricity-generating solar arrays. In addition, 15 ESA scientific and technical staff work at the STScI. In return for this contribution, European astronomers are entitled to 15 percent of the telescope's observing time, although currently they account for 20 percent of all observations. "This is a testimony to the quality of the European science community", said Dr Roger Bonnet, Director of Science at ESA. "We are only guaranteed 15 percent of the telescope's use, but consistently receive much more than that." Astronomers from universities, observatories and research institutes across Europe lead more than 60 investigations planned for the telescope's fifth observing cycle, which begins this summer. Many more Europeans contribute to teams led by other astronomers. Looking back to the very start of time European astronomer Dr Peter Jakobsen used ESA's Faint Object Camera to confirm that helium was present in the early Universe. Astronomers had long predicted that 90 percent of the newly born Universe consisted of hydrogen, with helium making up the remainder. Before the refurbished Hubble came along, it was easy to detect the hydrogen, but the primordial helium remained elusive. The ultraviolet capabilities of the telescope, combined with the improvement in spatial resolution following the repair, made it possible for Dr Jakobsen to obtain an image of a quasar close to the edge of the known Universe. A spectral analysis of this picture revealed the quasar's light, which took 13 billion years

  10. Career situation of female astronomers in Germany

    CERN Document Server

    Fohlmeister, J; 10.1002/asna.201211656

    2012-01-01

    We survey the job situation of women in astronomy in Germany and of German women abroad and review indicators for their career development. Our sample includes women astronomers from all academic levels from doctoral students to professors, as well as female astronomers who have left the field. We find that networking and human support are among the most important factors for success. Experience shows that students should carefully choose their supervisor and collect practical knowledge abroad. We reflect the private situation of female German astronomers and find that prejudices are abundant, and are perceived as discriminating.We identify reasons why women are more likely than men to quit astronomy after they obtain their PhD degree. We give recommendations to young students on what to pay attention to in order to be on the successful path in astronomy.

  11. Decoding the mechanisms of Antikythera astronomical device

    CERN Document Server

    Lin, Jian-Liang

    2016-01-01

    This book presents a systematic design methodology for decoding the interior structure of the Antikythera mechanism, an astronomical device from ancient Greece. The historical background, surviving evidence and reconstructions of the mechanism are introduced, and the historical development of astronomical achievements and various astronomical instruments are investigated. Pursuing an approach based on the conceptual design of modern mechanisms and bearing in mind the standards of science and technology at the time, all feasible designs of the six lost/incomplete/unclear subsystems are synthesized as illustrated examples, and 48 feasible designs of the complete interior structure are presented. This approach provides not only a logical tool for applying modern mechanical engineering knowledge to the reconstruction of the Antikythera mechanism, but also an innovative research direction for identifying the original structures of the mechanism in the future. In short, the book offers valuable new insights for all...

  12. Astronomers Without Borders: A Global Astronomy Community

    Science.gov (United States)

    Simmons, M.

    2011-10-01

    Astronomers Without Borders (AWB) brings together astronomy enthusiasts of all types - amateur astronomers, educators, professionals and "armchair" astronomers for a variety of online and physicalworld programs. The AWB web site provides social networking and a base for online programs that engage people worldwide in astronomy activities that transcend geopolitical and cultural borders. There is universal interest in astronomy, which has been present in all cultures throughout recorded history. Astronomy is also among the most accessible of sciences with the natural laboratory of the sky being available to people worldwide. There are few other interests for which people widely separated geographically can engage in activities involving the same objects. AWB builds on those advantages to bring people together. AWB also provides a platform where projects can reach a global audience. AWB also provides unique opportunities for multidisciplinary collaboration in EPO programs. Several programs including The World at Night, Global Astronomy Month and others will be described along with lessons learned.

  13. Thirteenth Joint European and National Astronomical Meeting

    CERN Document Server

    Iniesta, J C

    2006-01-01

    The book gathers the invited talks to the XIII JENAM conference, organized this time by the European Astronomical Society (EAS) and the Spanish Astronomical Society (SEA), and hosted by the Instituto de Astrofísica de Andalucía (CSIC). All branches of astrophysics are encompassed from the largest scales and cosmology to the solar system and the Sun, through the galaxies and the stars, including a section on astronomical instrumentation. Very relevant experts from all over the world speak in a single book about the most recent, exciting results from their fields in a way which is useful for both researchers in these fields and colleagues working in other disciplines. The book is accompanied by a CD-ROM including the remaining contributions of the meeting in PDF format, hence opening a wide panorama of what is going on in astrophysics nowadays.

  14. Making Access to Astronomical Software More Efficient

    CERN Document Server

    Grosbol, P

    2010-01-01

    Access to astronomical data through archives and VO is essential but does not solve all problems. Availability of appropriate software for analyzing the data is often equally important for the efficiency with which a researcher can publish results. A number of legacy systems (e.g. IRAF, MIDAS, Starlink, AIPS, Gipsy), as well as others now coming online are available but have very different user interfaces and may no longer be fully supported. Users may need multiple systems or stand-alone packages to complete the full analysis which introduces significant overhead. The OPTICON Network on `Future Astronomical Software Environments' and the USVAO have discussed these issues and have outlined a general architectural concept that solves many of the current problems in accessing software packages. It foresees a layered structure with clear separation of astronomical code and IT infrastructure. By relying on modern IT concepts for messaging and distributed execution, it provides full scalability from desktops to cl...

  15. ORCID Uptake in the Astronomical Community

    Science.gov (United States)

    Holmquist, Jane

    2015-08-01

    The IAU General Assembly provides librarians with a unique opportunity to interact with astronomers from all over the world. From the perspective of an ORCID Ambassador, the Focus Group Meeting on "Scholarly Publication in Astronomy" also provides an opportunity to demonstrate the cooperation and collaboration needed by individual astronomers, societies, librarians, publishers and bibliographic database providers to achieve universal adoption of ORCID, a standard unique identifier for authors, just as the DOI (digital object identifier) has been adopted for each journal article published.I propose to 1) present at the Focus Group Meeting an update on the uptake of ORCID by members of the astronomical community and 2) set up a small station (TBA) near the IAU registration area where librarians can show researchers how to register for an ORCID in 30 seconds.

  16. Hartung's Astronomical Objects for Southern Telescopes

    Science.gov (United States)

    Malin, David; Frew, David J.

    1995-10-01

    Many of the most spectacular astronomical objects are found in the southern skies. With this up-to-date, superbly illustrated handbook, both the amateur with binoculars and the expert with a telescope can make discoveries about new and interesting objects. Professor E. J. Hartung first produced his comprehensive and highly respected guide in 1968. Now the book has been greatly expanded and thoroughly revised, enhancing its character as an indispensable information source. With over 150 illustrations, new material is included on constellations and celestial coordinate systems as well as more modern descriptions of stars, nebulae and galaxies. The authors have included a new "southern Messier" list of objects. The authors' passion for their subject make this a unique and inspirational book. Many of the beautiful photographs were taken by David Malin, the world's leading astronomical photographer. The result will fascinate active and armchair astronomers alike.

  17. Astronomers Discover Most Massive Neutron Star Yet Known

    Science.gov (United States)

    2010-10-01

    Astronomers using the National Science Foundation's Green Bank Telescope (GBT) have discovered the most massive neutron star yet found, a discovery with strong and wide-ranging impacts across several fields of physics and astrophysics. "This neutron star is twice as massive as our Sun. This is surprising, and that much mass means that several theoretical models for the internal composition of neutron stars now are ruled out," said Paul Demorest, of the National Radio Astronomy Observatory (NRAO). "This mass measurement also has implications for our understanding of all matter at extremely high densities and many details of nuclear physics," he added. Neutron stars are the superdense "corpses" of massive stars that have exploded as supernovae. With all their mass packed into a sphere the size of a small city, their protons and electrons are crushed together into neutrons. A neutron star can be several times more dense than an atomic nucleus, and a thimbleful of neutron-star material would weigh more than 500 million tons. This tremendous density makes neutron stars an ideal natural "laboratory" for studying the most dense and exotic states of matter known to physics. The scientists used an effect of Albert Einstein's theory of General Relativity to measure the mass of the neutron star and its orbiting companion, a white dwarf star. The neutron star is a pulsar, emitting lighthouse-like beams of radio waves that sweep through space as it rotates. This pulsar, called PSR J1614-2230, spins 317 times per second, and the companion completes an orbit in just under nine days. The pair, some 3,000 light-years distant, are in an orbit seen almost exactly edge-on from Earth. That orientation was the key to making the mass measurement. As the orbit carries the white dwarf directly in front of the pulsar, the radio waves from the pulsar that reach Earth must travel very close to the white dwarf. This close passage causes them to be delayed in their arrival by the distortion of

  18. Effects of combined electron-beam irradiation and sous-vide treatments on microbiological and other qualities of chicken breast meat

    International Nuclear Information System (INIS)

    The microbiological safety, refrigeration shelf-life, and nutritional quality of chicken breast meat were investigated following combined electron-beam irradiation and cooking under vacuum (sous-vide). Chicken breast meat inoculated with 106 CFU/g of Listeria monocytogenes was irradiated with an electron beam at doses up to 3.1 kGy under vacuum in barrier bags, cooked in a boiling water bath for 3 min 45 s (previously determined to achieve an internal temperature of 71.1oC), and stored at 8oC for up to 5 weeks. Listeria was undetectable in samples treated with combined sous-vide and irradiation at 3.1 kGy, but the organism survived the sous-vide treatment without irradiation and multiplied during storage. A similar study, conducted with uninoculated chicken breast meat, revealed that the product which received both irradiation (3 kGy) and sous-vide treatment had a shelf-life of at least 8 weeks at 8oC, whereas the unirradiated samples treated sous-vide spoiled in 16 days. Listeria was undetectable in combination treated samples, but some of the unirradiated sous-vide samples tested after long storage showed high levels of Listeria. Some loss of thiamine occurred with the combined treatments. (author)

  19. A Novel Semantic Software for Astronomical Concepts

    CERN Document Server

    Heydari-Malayeri, M; Petit, F Le

    2012-01-01

    We have created a new semantic tool called AstroConcepts, providing definitions of astronomical concepts present on Web pages. This tool is a Google Chrome plug-in that interrogates the Etymological Dictionary of Astronomy and Astrophysics, developed at Paris Observatory. Thanks to this tool, if one selects an astronomical concept on a web page, a pop-up window will display the definition of the available English or French terms. Another expected use of this facility could be its implementation in Virtual Observatory services.

  20. APLpy: Astronomical Plotting Library in Python

    Science.gov (United States)

    Robitaille, Thomas; Bressert, Eli

    2012-08-01

    APLpy (the Astronomical Plotting Library in Python) is a Python module for producing publication-quality plots of astronomical imaging data in FITS format. The module uses Matplotlib, a powerful and interactive plotting package. It is capable of creating output files in several graphical formats, including EPS, PDF, PS, PNG, and SVG. Plots can be made interactively or by using scripts, and can generate co-aligned FITS cubes to make three-color RGB images. It also offers different overlay capabilities, including contour sets, markers with customizable symbols, and coordinate grids, and a range of other useful features.

  1. Computation of beam quality parameters for Mo/Mo, Mo/Rh, Rh/Rh, and W/Al target/filter combinations in mammography

    International Nuclear Information System (INIS)

    A computer program was implemented to predict mammography x-ray beam parameters in the range 20-40 kV for Mo/Mo, Mo/Rh, Rh/Rh, and W/Al target/filter combinations. The computation method used to simulate mammography x-ray spectra is based on the Boone et al. model. The beam quality parameters such as the half-value layer (HVL), the homogeneity coefficient (HC), and the average photon energy were computed by simulating the interaction of the spectrum photons with matter. The checking of this computation was done using a comparison of the results with published data and measured values obtained at the Netherlands Metrology Institute Van Swinden Laboratorium, National Institute of Standards and Technology, and International Atomic Energy Agency. The predicted values with a mean deviation of 3.3% of HVL, 3.7% of HC, and 1.5% of average photon energy show acceptable agreement with published data and measurements for all target/filter combinations in the 23-40 kV range. The accuracy of this computation can be considered clinically acceptable and can allow an appreciable estimation for the beam quality parameters

  2. A Test Facility For Astronomical X-Ray Optics

    DEFF Research Database (Denmark)

    Lewis, R. A.; Bordas, J.; Christensen, Finn Erland

    1989-01-01

    to approximate that encountered under working conditions, however the testing of these optical elements is notoriously difficult with conventional x-ray generators. Synchrotron Radiation (SR) sources are sufficiently brilliant to produce a nearly perfect parallel beam over a large area whilst still retaining......Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earths atmosphere. These devices require a large collection aperture and the imaging of an x-ray source which is essentially placed at infinity. The ideal testing system for these optical elements has...... a flux considerably higher than that available from conventional x-ray generators. A facility designed for the testing of x-ray optics, particularly in connection with x-ray telescopes is described below. It is proposed that this facility will be accommodated at the Synchrotron Radiation Source...

  3. Test facility for astronomical x-ray optics

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Lewis, Robert A.; Bordas, J.

    1990-01-01

    to approximate that encountered under working conditions; however, the testing of these optical elements is notoriously difficult with conventional x-ray generators. Synchrotron radiation (SR) sources are sufficiently brilliant to produce a nearly perfect parallel beam over a large area while still retaining......Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earth's atmosphere. These devices require a large collection aperture and the imaging of an x-ray source that is essentially placed at infinity. The ideal testing system for these optical elements has...... a flux considerably higher than that available from conventional x-ray generators. A facility designed for the testing of x-ray optics, particularly in connection with x-ray telescopes, is described. It is proposed that this facility will be accommodated at the Synchrotron Radiation Source...

  4. A Test Facility For Astronomical X-Ray Optics

    DEFF Research Database (Denmark)

    Lewis, R. A.; Bordas, J.; Christensen, Finn Erland

    1989-01-01

    approximate that encountered under working conditions, however the testing of these optical elements is notoriously difficult with conventional x-ray generators. Synchrotron Radiation (SR) sources are sufficiently brilliant to produce a nearly perfect parallel beam over a large area whilst still retaining a......Grazing incidence x-ray optics for x-ray astronomical applications are used outside the earths atmosphere. These devices require a large collection aperture and the imaging of an x-ray source which is essentially placed at infinity. The ideal testing system for these optical elements has to...... flux considerably higher than that available from conventional x-ray generators. A facility designed for the testing of x-ray optics, particularly in connection with x-ray telescopes is described below. It is proposed that this facility will be accommodated at the Synchrotron Radiation Source at the...

  5. Motion of dislocations in NaCl crystals at the combined action of mechanical and electromagnetic pulses generated by electron beam

    International Nuclear Information System (INIS)

    The effect of combined action of mechanical electromagnetic pulses, generated by electron beam, on the motion of the edge dislocations in the NaCl crystals is studied. The methodology of experiments is described in detail. Dependences of the dislocations average run length in the NaCl crystals on the magnetic field induction and electron beam current in absence of mechanical impact and by summarized action of the mechanical and electromagnetic fields are presented. The dependence of the run-length on the pressure mechanical pulses is obtained by deduction from the summarized run lengths of those runs, which were conditioned by the electromagnetic field. Good agreement of the experimental and calculational data indicates the additivity of mechanical and electromagnetic effects. The calculated coefficient of the dynamic breaking of the edge dislocations equals ∼ 2x10-4

  6. Multi-institutional phase II trial of intermediate risk prostate cancer treated with combination of external beam radiotherapy and high dose rate iridium brachytherapy

    International Nuclear Information System (INIS)

    A total of 84 intermediate risk prostate cancer (T2b or T2c, or 10< prostate specific antigen (PSA) ≤20 ng/ml, or Gleason score =7) patients were enrolled from five institutions. External beam radiotherapy were 3 Gy x 13 fraction =39 Gy and high dose rate iridium brachytherapy were 9 Gy x 2=18 Gy in one or two days. Primary endpoint of this study is the incidence of grade 3 late toxicity (NCI-CTC Ver.3) and secondary endpoint are acute toxicity and PSA relapse free rate. No grade 3 toxicity was observed and only one patient among 84 patients is noted PSA failure. Combined treatment of external beam radiotherapy and high dose rate iridium brachytherapy against intermediate risk of prostate cancer is safe and effective treatment. (author)

  7. Astronomers Detect Powerful Bursting Radio Source Discovery Points to New Class of Astronomical Objects

    Science.gov (United States)

    2005-03-01

    Astronomers at Sweet Briar College and the Naval Research Laboratory (NRL) have detected a powerful new bursting radio source whose unique properties suggest the discovery of a new class of astronomical objects. The researchers have monitored the center of the Milky Way Galaxy for several years and reveal their findings in the March 3, 2005 edition of the journal, “Nature”. This radio image of the central region of the Milky Way Galaxy holds a new radio source, GCRT J1745-3009. The arrow points to an expanding ring of debris expelled by a supernova. CREDIT: N.E. Kassim et al., Naval Research Laboratory, NRAO/AUI/NSF Principal investigator, Dr. Scott Hyman, professor of physics at Sweet Briar College, said the discovery came after analyzing some additional observations from 2002 provided by researchers at Northwestern University. “"We hit the jackpot!” Hyman said referring to the observations. “An image of the Galactic center, made by collecting radio waves of about 1-meter in wavelength, revealed multiple bursts from the source during a seven-hour period from Sept. 30 to Oct. 1, 2002 — five bursts in fact, and repeating at remarkably constant intervals.” Hyman, four Sweet Briar students, and his NRL collaborators, Drs. Namir Kassim and Joseph Lazio, happened upon transient emission from two radio sources while studying the Galactic center in 1998. This prompted the team to propose an ongoing monitoring program using the National Science Foundation’s Very Large Array (VLA) radio telescope in New Mexico. The National Radio Astronomy Observatory, which operates the VLA, approved the program. The data collected, laid the groundwork for the detection of the new radio source. “Amazingly, even though the sky is known to be full of transient objects emitting at X- and gamma-ray wavelengths,” NRL astronomer Dr. Joseph Lazio pointed out, “very little has been done to look for radio bursts, which are often easier for astronomical objects to produce

  8. Astroquery: querying astronomical web forms and databases

    OpenAIRE

    Sipocz, Brigitta

    2016-01-01

    Astroquery is an Astropy affiliated package for a set of tools for querying astronomical web forms and databases. In this lightning talk I give an overview of the available services and the usage of the package including a live demo of a typical use case.

  9. Astroquery: querying astronomical web forms and databases

    Science.gov (United States)

    Sipocz, Brigitta

    2016-03-01

    Astroquery is an Astropy affiliated package for a set of tools for querying astronomical web forms and databases. In this lightning talk I give an overview of the available services and the usage of the package including a live demo of a typical use case.

  10. An Astronomical Observatory in the Classroom

    Science.gov (United States)

    Lara, L.; Gallego, T.; de La Torre, A.

    We describe a project developed at the University of Granada in collaboration with the Instituto de Astrofísica de Andalucía aimed at using a remote telescope for live astronomical observations from the classroom. Available instrumentation, software and activities are presented.

  11. astLib: Tools for research astronomers

    Science.gov (United States)

    Hilton, Matt; Boada, Steven

    2016-07-01

    astLib is a set of Python modules for performing astronomical plots, some statistics, common calculations, coordinate conversions, and manipulating FITS images with World Coordinate System (WCS) information through PyWCSTools, a simple wrapping of WCSTools (ascl:1109.015).

  12. Astronomía en la cultura

    Science.gov (United States)

    López, A.; Giménez Benitez, S.; Fernández, L.

    La Astronomía en la Cultura es el estudio interdisciplinario a nivel global de la astronomía prehistórica, antigua y tradicional, en el marco de su contexto cultural. Esta disciplina abarca cualquier tipo de estudios o líneas de investigación en que se relacione a la astronomía con las ciencias humanas o sociales. En ella se incluyen tanto fuentes escritas, relatos orales como fuentes arqueológicas, abarcando entre otros, los siguientes temas: calendarios, observación práctica, cultos y mitos, representación simbólica de eventos, conceptos y objetos astronómicos, orientación astronómica de tumbas, templos, santuarios y centros urbanos, cosmología tradicional y la aplicación ceremonial de tradiciones astronómicas, la propia historia de la astronomía y la etnoastronomía (Krupp, 1989) (Iwaniszewski, 1994). En nuestro trabajo abordamos la historia y situación actual de esta disciplina, sus métodos y sus relaciones con otras áreas de investigación.

  13. The Virtual Astronomical Observatory Users Forum

    Science.gov (United States)

    Muench, August A.; Emery Bunn, S.; Astronomical Observatory, Virtual

    2013-01-01

    We present the online forum astrobabel.com, which has the goal of being a gathering place for the collective community intelligence about astronomical computing. The audience for this forum is anyone engaged in the analysis of astronomical or planetary data, whether that data be observational or theoretical. It is a free, community driven site where discussions are formulated primarily around the "question and answer" format. Current topics on the forum range from “Is there a photometry package in Python?” to “Where are the support forums for astronomy software packages?” and “Why is my SDSS SkyQuery query missing galaxies?” The poster will detail the full scope of discussions in the forum, and provide some basic guidelines for ensuring high quality forum posts. We will highlight the ways astronomers can discover and participate in discussions. Further, we view this as an excellent opportunity to gather feedback and feature requests from AAS221 attendees. Acknowledgement: The Virtual Astronomical Observatory (VAO) is managed by the VAO, LLC, a non-profit company established as a partnership of the Associated Universities, Inc. and the Association of Universities for Research in Astronomy, Inc. The VAO is sponsored by the National Science Foundation and the National Aeronautics and Space Administration.

  14. A novel respiratory motion compensation strategy combining gated beam delivery and mean target position concept - A compromise between small safety margins and long duty cycles

    International Nuclear Information System (INIS)

    Purpose: To evaluate a novel respiratory motion compensation strategy combining gated beam delivery with the mean target position (MTP) concept for pulmonary stereotactic body radiotherapy (SBRT). Materials and methods: Four motion compensation strategies were compared for 10 targets with motion amplitudes between 6 mm and 31 mm: the internal target volume concept (planITV); the MTP concept where safety margins were adapted based on 4D dose accumulation (planMTP); gated beam delivery without margins for motion compensation (plangated); a novel approach combining gating and the MTP concept (plangated and MTP). Results: For 5/10 targets with an average motion amplitude of 9 mm, the differences in the mean lung dose (MLD) between plangated and planMTP were gated and MTP. Despite significantly shorter duty cycles, plangated reduced the MLD by gated and MTP. The MLD was increased by 18% in planMTP compared to that of plangated and MTP. Conclusions: For pulmonary targets with motion amplitudes >10-15 mm, the combination of gating and the MTP concept allowed small safety margins with simultaneous long duty cycles.

  15. Beam-Beam Effects

    OpenAIRE

    Herr, W; Pieloni, T.

    2016-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities.

  16. Beam-Beam Effects

    CERN Document Server

    Herr, W

    2014-01-01

    One of the most severe limitations in high-intensity particle colliders is the beam-beam interaction, i.e. the perturbation of the beams as they cross the opposing beams. This introduction to beam-beam effects concentrates on a description of the phenomena that are present in modern colliding beam facilities.

  17. Sociological Profile of Astronomers in Spain

    Science.gov (United States)

    Iglesias de Ussel, Julio; Trinidad, Antonio; Ruiz, Diego; Battaner, Eduardo; Delgado, Antonio J.; Rodriguez-Espinosa, José M.; Salvador-Solé, Eduard; Torrelles, José M.

    In this paper the main findings are presented of a recent study made by a team of sociologists from the University of Granada on the professional astronomers currently working in Spain. Despite the peculiarities of this group - its youth, twentyfold increase in size over the last 20 years, and extremely high rate of specialization abroad - in comparison with other Spanish professionals, this is the first time that the sociological characteristics of the group have been studied discretely. The most significant results of the study are presented in the following sections. Section 1 gives a brief historical background of the development of Astronomy in Spain. Section 2 analyzes the socio-demographic profile of Spanish Astronomy professionals (sex, age, marital status, etc.). Sections 3-5 are devoted to the college education and study programs followed by Spanish astronomers, focusing on the features and evaluations of the training received, and pre- and postdoctoral study trips made to research centers abroad. The results for the latter clearly show the importance that Spanish astronomers place on having experience abroad. Special attention is paid to scientific papers published as a result of joint research projects carried out with colleagues from centers abroad as a result of these study trips. Section 6 describes the situation of Astronomy professionals within the Spanish job market, the different positions available and the time taken to find a job after graduation. Section 7 examines Astronomy as a discipline in Spain, including the astronomers' own opinions of the social status of the discipline within Spanish society. Particular attention is paid to how Spanish astronomers view the status of Astronomy in Spain in comparison with that of other European countries.

  18. Determining large deflections in rectangular combined loaded cantilever beams made of non-linear Ludwick type material by means of different arc length assumptions

    Indian Academy of Sciences (India)

    Ibrahim Eren

    2008-02-01

    In this study, large deflection of cantilever beams of Ludwick type material subjected to a combined loading consisting of a uniformly distributed load and one vertical concentrated load at the free end was investigated. In calculations, both material and geometrical non-linearity have been considered. Horizontal and vertical deflections magnitudes were calculated throughout Euler–Bernoulli curvature-moment relationship assuming different arc lengths. Vertical deflections were calculated by using Runge–Kutta method. More simple and easily understandable results have been obtained compared to the previous studies about the issue and compatible values have been obtained for most of the compared values.

  19. Relativistic scaling of astronomical quantities and the system of astronomical units

    OpenAIRE

    Klioner, Sergei A.

    2005-01-01

    For relativistic modelling of high-accuracy astronomical data several time scales are used: barycentric and geocentric coordinate times, TCB and TCG, as well as two additional time scales, TDB and TT, that are defined as linear functions of TCB and TCG, respectively. The paper is devoted to a concise but still detailed explanation of the reasons and the implications of the relativistic scalings of astronomical quantities induced by the time scales TDB and TT. We consequently distinguish betwe...

  20. Astronomical Orientation of Pyramid Tombs in North China

    Science.gov (United States)

    Rusell Tiede, Vance

    2010-01-01

    Two ancient Chinese texts, the Chou Bei Suan Ching and Chou Li (Western Han Dynasty, ca. 100 BC), record that the Imperial Astronomer (Feng Hsian Shin) made solar observations to determine the solstices and equinoxes, and for determining the cardinal directions with a circle and gnomon. By combining the techniques of astro-archaeology (G. S. Hawkins, 1968) with both overhead imagery and ground survey, the present study seeks to link historical Chinese descriptions of astronomical phenomena with contemporary architectural orientation. In the process, several unexpected astronomical orientation patterns emerged which apparently do not appear in the surviving historical record. For example, at the imperial Western Han capital of Ch'ang-an (N 34° latitude), the diagonals of cardinally oriented square pyramid mounds (ling) align to zenith (+34° declination) and nadir (-34° declination) star rise and set points on the skyline. This is in accord with the Chou (Zhou) Dynasty's name of Chung-Kuo, meaning Central Country or Middle Kingdom. That is, the imperial capital is centered both politico-geographically with respect to its vassal states of the Eastern Yi, Southern Man, Western Rong, and Northern Di, as well as astro-geomantically regarding the color-coded Five Sacred Directions East-South-West-North-Zenith/Nadir in the Cosmos. Our ground survey also confirmed pyramid orientation to the lunar standstills (+28°, +18° and +5° declination) that we reported from overhead imagery in 1980 (155th AAS Meeting, HAD 18.CE.12, Lunar and Solar Alignments of Ancient Chinese Pyramids). Grateful acknowledgment is given to the Chinese Academy of Sciences for the invitation to conduct an astro-archaeological survey of the Wei-ho valley, Shensi (Shaanxi) Province.

  1. A modelled comparison of prostate cancer control rates after high-dose-rate brachytherapy (3145 multicentre patients) combined with, or in contrast to, external-beam radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: To analyse biochemical relapse-free-survival results for prostate cancer patients receiving combined external beam and high-dose-rate brachytherapy, in comparison with expected results using projections based on dose/fractionation/response parameter values deduced from a previous external-beam-alone 5969-patient multicentre dataset. Material and methods: Results on a total of 3145 prostate cancer patients receiving brachytherapy (BT) as part or all of their treatment were collected from 10 institutions, and subjected to linear-quadratic (LQ) modelling of dose response and fractionation parameters. Results: Treatments with BT components of less than 25 Gy, 3–4 BT fractions, doses per BT fraction up to 6 Gy, and treatment times of 3–7 weeks, all gave outcomes expected from LQ projections of the external-beam-alone data (α/β = 1.42 Gy). However, BT doses higher than 30 Gy, 1–2 fractions, 9 fractions (BT alone), doses per fraction of 9–15 Gy, and treatment in only 1 week (one example), gave local control levels lower than the expected levels by up to ∼35%. Conclusions: There are various potential causes of the lower-than-projected control levels for some schedules of brachytherapy: it seems plausible that cold spots in the brachytherapy dose distribution may be contributory, and the applicability of the LQ model at high doses per fraction remains somewhat uncertain. The results of further trials may help elucidate the true benefit of hypofractionated high-dose-rate brachytherapy

  2. A combined crossed molecular beams and theoretical study of the reaction CN + C{sub 2}H{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Balucani, Nadia, E-mail: nadia.balucani@unipg.it [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia (Italy); Leonori, Francesca; Petrucci, Raffaele [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia (Italy); Wang, Xingan [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia (Italy); Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); Casavecchia, Piergiorgio [Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Perugia (Italy); Skouteris, Dimitrios [Scuola Normale Superiore, Pisa (Italy); Albernaz, Alessandra F. [Instituto de Física, Universidade de Brasília, Brasília (Brazil); Gargano, Ricardo [Instituto de Física, Universidade de Brasília, Brasília (Brazil); Departments of Chemistry and Physics, University of Florida, Quantum Theory Project, Gainesville, FL 32611 (United States)

    2015-03-01

    Highlights: • The CN + C{sub 2}H{sub 4} reaction was investigated in crossed beam experiments. • Electronic structure calculations of the potential energy surface were performed. • RRKM estimates qualitatively reproduce the experimental C{sub 2}H{sub 3}NC yield. - Abstract: The CN + C{sub 2}H{sub 4} reaction has been investigated experimentally, in crossed molecular beam (CMB) experiments at the collision energy of 33.4 kJ/mol, and theoretically, by electronic structure calculations of the relevant potential energy surface and Rice–Ramsperger–Kassel–Marcus (RRKM) estimates of the product branching ratio. Differently from previous CMB experiments at lower collision energies, but similarly to a high energy study, we have some indication that a second reaction channel is open at this collision energy, the characteristics of which are consistent with the channel leading to CH{sub 2}CHNC + H. The RRKM estimates using M06L electronic structure calculations qualitatively support the experimental observation of C{sub 2}H{sub 3}NC formation at this and at the higher collision energy of 42.7 kJ/mol of previous experiments.

  3. Public Perception of Astronomers: Revered, Reviled and Ridiculed

    OpenAIRE

    West, Michael J.

    2009-01-01

    Society's view of astronomers has changed over time and from culture to culture. This review discusses some of the many ways that astronomers have been perceived by their societies and suggests ways that astronomers can influence public perception of ourselves and our profession in the future.

  4. Finding Hidden Treasures: Investigations in US Astronomical Plate Archives

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Hudec, L.

    2013-01-01

    Roč. 53, č. 1 (2013), s. 23-26. ISSN 1210-2709 R&D Projects: GA ČR GA205/08/1207 Institutional support: RVO:67985815 Keywords : astronomical data archives * astronomical photography * astronomical photographic archives Subject RIV: BH - Optics, Masers, Lasers

  5. The Relationships of the Maxillary Sinus With the Superior Alveolar Nerves and Vessels as Demonstrated by Cone-Beam CT Combined With μ-CT and Histological Analyses.

    Science.gov (United States)

    Kasahara, Norio; Morita, Wataru; Tanaka, Ray; Hayashi, Takafumi; Kenmotsu, Shinichi; Ohshima, Hayato

    2016-05-01

    There are no available detailed data on the three-dimensional courses of the human superior alveolar nerves and vessels. This study aimed to clarify the relationships of the maxillary sinus with the superior alveolar nerves and vessels using cone-beam computed tomography (CT) combined with μ-CT and histological analyses. Digital imaging and communication in medicine data obtained from the scanned heads/maxillae of cadavers used for undergraduate/postgraduate dissection practice and skulls using cone-beam CT were reconstructed into three-dimensional (3D) images using software. The 3D images were compared with μ-CT images and histological sections. Cone-beam CT clarified the relationships of the maxillary sinus with the superior alveolar canals/grooves. The main anterior superior alveolar canal/groove ran anteriorly through the upper part of the sinus and terminated at the bottom of the nasal cavity near the piriform aperture. The main middle alveolar canal ran downward from the upper part of the sinus to ultimately join the anterior one. The main posterior alveolar canal ran through the lateral lower part of the sinus and communicated with the anterior one. Histological analyses demonstrated the existence of nerves and vessels in these canals/grooves, and the quantities of these structures varied across each canal/groove. Furthermore, the superior dental nerve plexus exhibited a network that was located horizontally to the occlusal plane, although these nerve plexuses appeared to be the vertical network that is described in most textbooks. In conclusion, cone-beam CT is suggested to be a useful method for clarifying the superior alveolar canals/grooves including the nerves and vessels. Anat Rec, 299:669-678, 2016. © 2016 Wiley Periodicals, Inc. PMID:26874792

  6. Improving 4D plan quality for PBS-based liver tumour treatments by combining online image guided beam gating with rescanning

    Science.gov (United States)

    Zhang, Ye; Knopf, Antje-Christin; Weber, Damien Charles; Lomax, Antony John

    2015-10-01

    Pencil beam scanned (PBS) proton therapy has many advantages over conventional radiotherapy, but its effectiveness for treating mobile tumours remains questionable. Gating dose delivery to the breathing pattern is a well-developed method in conventional radiotherapy for mitigating tumour-motion, but its clinical efficiency for PBS proton therapy is not yet well documented. In this study, the dosimetric benefits and the treatment efficiency of beam gating for PBS proton therapy has been comprehensively evaluated. A series of dedicated 4D dose calculations (4DDC) have been performed on 9 different 4DCT(MRI) liver data sets, which give realistic 4DCT extracting motion information from 4DMRI. The value of 4DCT(MRI) is its capability of providing not only patient geometries and deformable breathing characteristics, but also includes variations in the breathing patterns between breathing cycles. In order to monitor target motion and derive a gating signal, we simulate time-resolved beams’ eye view (BEV) x-ray images as an online motion surrogate. 4DDCs have been performed using three amplitude-based gating window sizes (10/5/3 mm) with motion surrogates derived from either pre-implanted fiducial markers or the diaphragm. In addition, gating has also been simulated in combination with up to 19 times rescanning using either volumetric or layered approaches. The quality of the resulting 4DDC plans has been quantified in terms of the plan homogeneity index (HI), total treatment time and duty cycle. Results show that neither beam gating nor rescanning alone can fully retrieve the plan homogeneity of the static reference plan. Especially for variable breathing patterns, reductions of the effective duty cycle to as low as 10% have been observed with the smallest gating rescanning window (3 mm), implying that gating on its own for such cases would result in much longer treatment times. In addition, when rescanning is applied on its own, large differences between volumetric

  7. Improving 4D plan quality for PBS-based liver tumour treatments by combining online image guided beam gating with rescanning

    International Nuclear Information System (INIS)

    Pencil beam scanned (PBS) proton therapy has many advantages over conventional radiotherapy, but its effectiveness for treating mobile tumours remains questionable. Gating dose delivery to the breathing pattern is a well-developed method in conventional radiotherapy for mitigating tumour-motion, but its clinical efficiency for PBS proton therapy is not yet well documented. In this study, the dosimetric benefits and the treatment efficiency of beam gating for PBS proton therapy has been comprehensively evaluated. A series of dedicated 4D dose calculations (4DDC) have been performed on 9 different 4DCT(MRI) liver data sets, which give realistic 4DCT extracting motion information from 4DMRI. The value of 4DCT(MRI) is its capability of providing not only patient geometries and deformable breathing characteristics, but also includes variations in the breathing patterns between breathing cycles. In order to monitor target motion and derive a gating signal, we simulate time-resolved beams’ eye view (BEV) x-ray images as an online motion surrogate. 4DDCs have been performed using three amplitude-based gating window sizes (10/5/3 mm) with motion surrogates derived from either pre-implanted fiducial markers or the diaphragm. In addition, gating has also been simulated in combination with up to 19 times rescanning using either volumetric or layered approaches. The quality of the resulting 4DDC plans has been quantified in terms of the plan homogeneity index (HI), total treatment time and duty cycle. Results show that neither beam gating nor rescanning alone can fully retrieve the plan homogeneity of the static reference plan. Especially for variable breathing patterns, reductions of the effective duty cycle to as low as 10% have been observed with the smallest gating rescanning window (3 mm), implying that gating on its own for such cases would result in much longer treatment times. In addition, when rescanning is applied on its own, large differences between volumetric

  8. Using Astronomical Photographs to Investigate Misconceptions about Galaxies and Spectra: Question Development for Clicker Use

    CERN Document Server

    Lee, Hyunju

    2015-01-01

    Many topics in introductory astronomy at the college or high-school level rely implicitly on using astronomical photographs and visual data in class. However, students bring many preconceptions to their understanding of these materials that ultimately lead to misconceptions, and research about students' interpretation of astronomical images has been scarcely conducted. In this study we probed college students' understanding of astronomical photographs and visual data about galaxies and spectra, and developed a set of concept questions based on their common misconceptions. The study was conducted mainly in three successive surveys: 1) open-ended questions looking for students' ideas and common misconceptions, 2) combined multiple-choice and open-ended questions seeking to explore student reasoning and to improve concept questions for clickers, and 3) a finalized version of the concept questions used to investigate the strength of each misconception among the students in introductory astronomy courses. This stu...

  9. Anomalous Post-Newtonian terms and the secular increase of the Astronomical Unit

    CERN Document Server

    Acedo, L

    2014-01-01

    In the last decade a major debate has emerged on the astrophysics community concerning the anomalous behaviour of the astronomical unit, the fundamental scale of distances in the Solar system. Several independent studies have combined radar ranging and optical data from the last four decades to come to the conclusion that the astronomical unit is increasing by several meters per century. It is abundantly clear that General Relativity cannot account for this new effect, although an still undefined angular momentum transfer mechanism could provide the simpler and more conventional explanation. Here we investigate several anomalous post-newtonian terms containing only the product of the mass and angular momentum of the Sun as well as its Schwarzschild radius in order to determine if they could explain the secular increase of the astronomical unit and the recently reported increase of Lunar eccentricity. If these anomalies are confirmed, searching for a modification of General Relativity predicting these terms co...

  10. Leveraging data lineage to infer logical relationships between astronomical catalogs

    Science.gov (United States)

    Buddelmeijer, Hugo; Valentijn, Edwin A.

    2013-01-01

    A novel method to infer logical relationships between sets is presented. These sets can be any collection of elements, for example astronomical catalogs of celestial objects. The method does not require the contents of the sets to be known explicitly. It combines incomplete knowledge about the relationships between sets to infer a priori unknown relationships. Relationships between sets are represented by sets of Boolean hypercubes. This leads to deductive reasoning by application of logical operators to these sets of hypercubes. A pseudo code for an efficient implementation is described. The method is used in the Astro-WISE information system to infer relationships between catalogs of astronomical objects. These catalogs can be very large and, more importantly, their contents do not have to be available at all times. Science products are stored in Astro-WISE with references to other science products from which they are derived, or their dependencies. This creates a full data lineage that links every science product all the way back to the raw data. Catalogs are created in a way that maximizes knowledge about their relationship with their dependencies. The presented algorithm is used to determine which objects a catalog represents by leveraging this information.

  11. Combined photon-electron beams in the treatment of the supraclavicular lymph nodes in breast cancer: A novel technique that achieves adequate coverage while reducing lung dose

    Energy Technology Data Exchange (ETDEWEB)

    Salem, Ahmed, E-mail: ahmed.salem@doctors.org.uk [Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Mohamad, Issa; Dayyat, Abdulmajeed [Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Kanaa’n, Haitham [Section of Medical Physics, Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Sarhan, Nasim [Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Roujob, Ibrahim [Section of Medical Physics, Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Salem, Abdel-Fattah [Department of Obstetrics and Gynecology, Hashemite University, Zarqa (Jordan); Afifi, Shatha [Section of Medical Physics, Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan); Jaradat, Imad; Mubiden, Rasmi; Almousa, Abdelateif [Department of Radiation Oncology, King Hussein Cancer Center, Amman (Jordan)

    2015-10-01

    Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-electron, photon-only, and electron-only supraclavicular beams. A dose of 50 Gy over 25 fractions was prescribed. Chest wall irradiation parameters were fixed for all plans. The goal of this planning effort was to cover 95% of the supraclavicular clinical target volume (CTV) with 95% of the prescribed dose and to minimize the volume receiving ≥ 105% of the dose. Comparative end points were supraclavicular CTV coverage (volume covered by the 95% isodose line), hotspot volume, maximum radiation dose, contralateral breast dose, mean total lung dose, total lung volume percentage receiving at least 20 Gy (V{sub 20} {sub Gy}), heart volume percentage receiving at least 25 Gy (V{sub 25} {sub Gy}). Electron and photon energies ranged from 8 to 18 MeV and 4 to 6 MV, respectively. The ratio of photon-to-electron fractions in combined beams ranged from 5:20 to 15:10. Supraclavicular nodal coverage was highest in photon-only (mean = 96.2 ± 3.5%) followed closely by combined photon-electron (mean = 94.2 ± 2.5%) and lowest in electron-only plans (mean = 81.7 ± 14.8%, p < 0.001). The volume of tissue receiving ≥ 105% of the prescription dose was higher in the electron-only (mean = 69.7 ± 56.1 cm{sup 3}) as opposed to combined photon-electron (mean = 50.8 ± 40.9 cm{sup 3}) and photon-only beams (mean = 32.2 ± 28.1 cm{sup 3}, p = 0.114). Heart V{sub 25} {sub Gy} was not statistically different among the plans (p = 0.999). Total lung V{sub 20} {sub Gy} was lowest in electron-only (mean = 10.9 ± 2.3%) followed by combined photon-electron (mean = 13.8 ± 2.3%) and highest in photon

  12. Combined photon-electron beams in the treatment of the supraclavicular lymph nodes in breast cancer: A novel technique that achieves adequate coverage while reducing lung dose

    International Nuclear Information System (INIS)

    Radiation pneumonitis is a well-documented side effect of radiation therapy for breast cancer. The purpose of this study was to compare combined photon-electron, photon-only, and electron-only plans in the radiation treatment of the supraclavicular lymph nodes. In total, 13 patients requiring chest wall and supraclavicular nodal irradiation were planned retrospectively using combined photon-electron, photon-only, and electron-only supraclavicular beams. A dose of 50 Gy over 25 fractions was prescribed. Chest wall irradiation parameters were fixed for all plans. The goal of this planning effort was to cover 95% of the supraclavicular clinical target volume (CTV) with 95% of the prescribed dose and to minimize the volume receiving ≥ 105% of the dose. Comparative end points were supraclavicular CTV coverage (volume covered by the 95% isodose line), hotspot volume, maximum radiation dose, contralateral breast dose, mean total lung dose, total lung volume percentage receiving at least 20 Gy (V20 Gy), heart volume percentage receiving at least 25 Gy (V25 Gy). Electron and photon energies ranged from 8 to 18 MeV and 4 to 6 MV, respectively. The ratio of photon-to-electron fractions in combined beams ranged from 5:20 to 15:10. Supraclavicular nodal coverage was highest in photon-only (mean = 96.2 ± 3.5%) followed closely by combined photon-electron (mean = 94.2 ± 2.5%) and lowest in electron-only plans (mean = 81.7 ± 14.8%, p < 0.001). The volume of tissue receiving ≥ 105% of the prescription dose was higher in the electron-only (mean = 69.7 ± 56.1 cm3) as opposed to combined photon-electron (mean = 50.8 ± 40.9 cm3) and photon-only beams (mean = 32.2 ± 28.1 cm3, p = 0.114). Heart V25 Gy was not statistically different among the plans (p = 0.999). Total lung V20 Gy was lowest in electron-only (mean = 10.9 ± 2.3%) followed by combined photon-electron (mean = 13.8 ± 2.3%) and highest in photon-only plans (mean = 16.2 ± 3%, p < 0.001). As expected, photon

  13. Training the Next Generation of Astronomers

    CERN Document Server

    Williams, Peter K G; Maness, Holly; Modjaz, Maryam; Shapiro, Kristen L; Silverman, Jeffrey M; Strubbe, Linda; Adams, Betsey; Alatalo, Katherine; Chiu, Kuenley; Claire, Mark; Cobb, Bethany; Cruz, Kelle; Desroches, Louis-Benoit; Enoch, Melissa; Hull, Chat; Jang-Condell, Hannah; Law, Casey; McConnell, Nicholas; Meijerink, Rowin; Offner, Stella; Parejko, John K; Pober, Jonathan; Pontoppidan, Klaus; Poznanski, Dovi; Seth, Anil; Stahler, Steven; Walkowicz, Lucianne; West, Andrew A; Wetzel, Andrew; Whysong, David

    2009-01-01

    While both society and astronomy have evolved greatly over the past fifty years, the academic institutions and incentives that shape our field have remained largely stagnant. As a result, the astronomical community is faced with several major challenges, including: (1) the training that we provide does not align with the skills that future astronomers will need, (2) the postdoctoral phase is becoming increasingly demanding and demoralizing, and (3) our jobs are increasingly unfriendly to families with children. Solving these problems will require conscious engineering of our profession. Fortunately, this Decadal Review offers the opportunity to revise outmoded practices to be more effective and equitable. The highest priority of the Subcommittee on the State of the Profession should be to recommend specific, funded activities that will ensure the field meets the challenges we describe.

  14. Physicists, Mathematicians and Astronomers- communists (Part 2)

    Science.gov (United States)

    Gaina, Alex

    The second part is continuig the edition of communists (physicists, mathematicians, astronomers), which were not included in the reference books by Yu.A. Hramov, A. N. Bogoliubov, I.G. Kolchinskii et al.. The author is discussing here also the relation between business and Communist party, especially in the Post Soviet Russia. A discussion of the biographies of Soviet scientists included in the Britannica is given, as well as a list of Russian scientists included in the Oxford Dictionary of Physics is given. Another part of the paper is pointing out the defficiencies of the last edition of the Great Russian Encyclopedic Dictionary (Drofa Eds, Moscow, 2009) in what concerns physicists, mathematicians and astronomers. A great number of Nobel Prize Winners was ommited in the edition of 2009.

  15. International Astronomical Union Sympoisum No.50

    CERN Document Server

    Westerlund, B

    1973-01-01

    Dr J. Landi Dessy, Director of the Astronomical Observatory, Cordoba, Argentina, invited the International Astronomical Union to hold a Symposium in Cordoba in connection with the celebration of the Centennial of the Cordoba Observatory; the date of foundation is October 24, 1871. He proposed that the Symposium should deal with Spectral Classification and Multicolour Photometry as seven years had elapsed since the Symposium No. 24 in Saltsj6baden, and much development had occurred in the field. The invitation and the proposal were accepted by the IAU, and the Symposium was held in Villa Carlos Paz, near Cordoba, between October 18 and October 24, 1971. It was attended by about 50 scientists representing Argentina, Canada, Chile, Den­ mark, France, Germany, Italy, Mexico, Sweden, Switzerland, U.K., U.S.A., Vatican City State and Venezuela. The Symposium was divided into four sessions: 1. Classification of slit spectra, 2. Classification of objective-prism spectra, 3. Photometric classification, 4. Catalogues ...

  16. Astronomía Mocoví

    Science.gov (United States)

    López, A.; Giménez Benitez, S.; Fernández, L.

    El presente trabajo, es una revisión crítica de la astronomía en la cultura Mocoví, aportando a lo realizado previamente por Lehmann Nistche (Lehmann Nistche, 1924 y 1927) el resultado de nuestro trabajo de campo. Un mayor conocimiento de las cosmovisiones de las etnias de esta área es fundamental para una mejor comprensión de la dispersión de las ideas cosmológicas entre los pueblos aborígenes americanos, dada la importancia del corredor chaqueño como conexión entre las altas culturas andinas, la mesopotamia y la región pampeana (Susnik, 1972). Para ello se realiza una comparación con otras cosmovisiones del área americana. Nuestro aporte se enmarca dentro de las actuales líneas de trabajo mundialmente en desarrollo en Astronomía en la Cultura.

  17. The data analysis facilities that astronomers want

    International Nuclear Information System (INIS)

    This paper discusses the need and importance of data analysis facilities and what astronomers ideally want. A brief survey is presented of what is available now and some of the main deficiencies and problems with today's systems are discussed. The main sources of astronomical data are presented incuding: optical photographic, optical TV/CCD, VLA, optical spectros, imaging x-ray satellite, and satellite planetary camera. Landmark discoveries are listed in a table, some of which include: our galaxy as an island, distance to stars, H-R diagram (stellar structure), size of our galaxy, and missing mass in clusters. The main problems at present are discussed including lack of coordinated effort and central planning, differences in hardware, and measuring performance

  18. Recruitment and Retention of LGBTIQ Astronomers

    Science.gov (United States)

    Dixon, William Van Dyke

    2012-01-01

    While lesbian, gay, bisexual, transgender, intersex, or questioning (LGBTIQ) astronomers face many of the same workplace challenges as women and racial/ethnic minorities, from implicit bias to overt discrimination, other challenges are unique to this group. An obvious example is the absence at many institutions of health insurance and other benefits for the same-sex domestic partners of their employees. More subtle is the psychological toll paid by LGBTIQ astronomers who remain "in the closet," self-censoring every statement about their personal lives. Paradoxically, the culture of the physical sciences, in which sexuality, gender identity, and gender expression are considered irrelevant, can discourage their discussion, further isolating LGBTIQ researchers. Addressing these challenges is not just a matter of fairness; it is an essential tool in the recruitment and retention of the brightest researchers and in assuring their productivity. We will discuss these issues and what individuals and departments can to make their institutions more welcoming to their LGBTIQ colleagues.

  19. Bayesian mixture models for Poisson astronomical images

    CERN Document Server

    Guglielmetti, Fabrizia; Dose, Volker

    2012-01-01

    Astronomical images in the Poisson regime are typically characterized by a spatially varying cosmic background, large variety of source morphologies and intensities, data incompleteness, steep gradients in the data, and few photon counts per pixel. The Background-Source separation technique is developed with the aim to detect faint and extended sources in astronomical images characterized by Poisson statistics. The technique employs Bayesian mixture models to reliably detect the background as well as the sources with their respective uncertainties. Background estimation and source detection is achieved in a single algorithm. A large variety of source morphologies is revealed. The technique is applied in the X-ray part of the electromagnetic spectrum on ROSAT and Chandra data sets and it is under a feasibility study for the forthcoming eROSITA mission.

  20. Statistical methods for astronomical data analysis

    CERN Document Server

    Chattopadhyay, Asis Kumar

    2014-01-01

    This book introduces “Astrostatistics” as a subject in its own right with rewarding examples, including work by the authors with galaxy and Gamma Ray Burst data to engage the reader. This includes a comprehensive blending of Astrophysics and Statistics. The first chapter’s coverage of preliminary concepts and terminologies for astronomical phenomenon will appeal to both Statistics and Astrophysics readers as helpful context. Statistics concepts covered in the book provide a methodological framework. A unique feature is the inclusion of different possible sources of astronomical data, as well as software packages for converting the raw data into appropriate forms for data analysis. Readers can then use the appropriate statistical packages for their particular data analysis needs. The ideas of statistical inference discussed in the book help readers determine how to apply statistical tests. The authors cover different applications of statistical techniques already developed or specifically introduced for ...

  1. Identifying seasonal stars in Kaurna astronomical traditions

    CERN Document Server

    Hamacher, Duane W

    2015-01-01

    Early ethnographers and missionaries recorded Aboriginal languages and oral traditions across Australia. Their general lack of astronomical training resulted in misidentifications, transcription errors, and omissions in these records. Additionally, many of these early records are fragmented. In western Victoria and southeast South Australia, many astronomical traditions were recorded, but curiously, some of the brightest stars in the sky were omitted. Scholars claimed these stars did not feature in Aboriginal traditions. This under-representation continues to be repeated in the literature, but current research shows that some of these stars may in fact feature in Aboriginal traditions and could be seasonal calendar markers. This paper uses established techniques in cultural astronomy to identify seasonal stars in the traditions of the Kaurna Aboriginal people of the Adelaide Plains, South Australia.

  2. Local sparse representation for astronomical image denoising

    Institute of Scientific and Technical Information of China (English)

    杨阿锋; 鲁敏; 滕书华; 孙即祥

    2013-01-01

    Motivated by local coordinate coding(LCC) theory in nonlinear manifold learning, a new image representation model called local sparse representation(LSR) for astronomical image denoising was proposed. Borrowing ideas from surrogate function and applying the iterative shrinkage-thresholding algorithm(ISTA), an iterative shrinkage operator for LSR was derived. Meanwhile, a fast approximated LSR method by first performing a K-nearest-neighbor search and then solving a l1optimization problem was presented under the guarantee of denoising performance. In addition, the LSR model and adaptive dictionary learning were incorporated into a unified optimization framework, which explicitly established the inner connection of them. Such processing allows us to simultaneously update sparse coding vectors and the dictionary by alternating optimization method. The experimental results show that the proposed method is superior to the traditional denoising method and reaches state-of-the-art performance on astronomical image.

  3. Detecting Diffuse Sources in Astronomical Images

    CERN Document Server

    Butler-Yeoman, T; Hollitt, C P; Hogg, D W; Johnston-Hollitt, M

    2016-01-01

    We present an algorithm capable of detecting diffuse, dim sources of any size in an astronomical image. These sources often defeat traditional methods for source finding, which expand regions around points of high intensity. Extended sources often have no bright points and are only detectable when viewed as a whole, so a more sophisticated approach is required. Our algorithm operates at all scales simultaneously by considering a tree of nested candidate bounding boxes, and inverts a hierarchical Bayesian generative model to obtain the probability of sources existing at given locations and sizes. This model naturally accommodates the detection of nested sources, and no prior knowledge of the distribution of a source, or even the background, is required. The algorithm scales nearly linear with the number of pixels making it feasible to run on large images, and requires minimal parameter tweaking to be effective. We demonstrate the algorithm on several types of astronomical and artificial images.

  4. Atomic and Molecular Aspects of Astronomical Spectra

    CERN Document Server

    Sochi, Taha

    2012-01-01

    In the first section we present the atomic part where a C2+ atomic target was prepared and used to generate theoretical data to investigate recombination lines arising from electron-ion collisions in thin plasma. R-matrix method was used to describe the C2+ plus electron system. Theoretical data concerning bound and autoionizing states were generated in the intermediate-coupling approximation. The data were used to generate dielectronic recombination data for C+ which include transition lines, oscillator strengths, radiative transition probabilities, emissivities and dielectronic recombination coefficients. The data were cast in a line list containing 6187 optically-allowed transitions which include many C II lines observed in astronomical spectra. This line list was used to analyze the spectra from a number of astronomical objects, mainly planetary nebulae, and identify their electron temperature. The electron temperature investigation was also extended to include free electron energy analysis to investigate...

  5. Astronomical Image Denoising Using Dictionary Learning

    CERN Document Server

    Beckouche, Simon; Fadili, Jalal

    2013-01-01

    Astronomical images suffer a constant presence of multiple defects that are consequences of the intrinsic properties of the acquisition equipments, and atmospheric conditions. One of the most frequent defects in astronomical imaging is the presence of additive noise which makes a denoising step mandatory before processing data. During the last decade, a particular modeling scheme, based on sparse representations, has drawn the attention of an ever growing community of researchers. Sparse representations offer a promising framework to many image and signal processing tasks, especially denoising and restoration applications. At first, the harmonics, wavelets, and similar bases and overcomplete representations have been considered as candidate domains to seek the sparsest representation. A new generation of algorithms, based on data-driven dictionaries, evolved rapidly and compete now with the off-the-shelf fixed dictionaries. While designing a dictionary beforehand leans on a guess of the most appropriate repre...

  6. Bad pixel modified interpolation for astronomical images

    CERN Document Server

    Popowicz, A; Filus, Z

    2013-01-01

    We present a new method of interpolation for the pixel brightness estimation in astronomical images. Our new method is simple and easily implementable. We show the comparison of this method with the widely used linear interpolation and other interpolation algorithms using one thousand astronomical images obtained from the Sloan Digital Sky Survey. The comparison shows that our method improves bad pixels brightness estimation with four times lower mean error than the presently most popular linear interpolation and has a better performance than any other examined method. The presented idea is flexible and can be also applied to presently used and future interpolation methods. The proposed method is especially useful for large sky surveys image reduction but can be also applied to single image correction.

  7. Identifying seasonal stars in Kaurna astronomical traditions

    Science.gov (United States)

    Hamacher, Duane W.

    2015-03-01

    Early ethnographers and missionaries recorded Aboriginal languages and oral traditions across Australia. Their general lack of astronomical training resulted in misidentifications, transcription errors and omissions in these records. In western Victoria and southeast South Australia many astronomical traditions were recorded but, cur- iously, some of the brightest stars in the sky were omitted. Scholars claimed these stars did not feature in Aboriginal traditions. This continues to be repeated in the literature, but current research shows that these stars may in fact feature in Aboriginal traditions and could be seasonal calendar markers. This paper uses established techniques to identify seasonal stars in the traditions of the Kaurna Aboriginal people of the Adelaide Plains, South Australia.

  8. Query driven visualization of astronomical catalogs

    Science.gov (United States)

    Buddelmeijer, Hugo; Valentijn, Edwin A.

    2013-01-01

    Interactive visualization of astronomical catalogs requires novel techniques due to the huge volumes and complex structure of the data produced by existing and upcoming astronomical surveys. The creation as well as the disclosure of the catalogs can be handled by data pulling mechanisms (Buddelmeijer et al. 2011). These prevent unnecessary processing and facilitate data sharing by having users request the desired end products. In this work we present query driven visualization as a logical continuation of data pulling. Scientists can request catalogs in a declarative way and set process parameters directly from within the visualization. This results in profound interoperation between software with a high level of abstraction. New messages for the Simple Application Messaging Protocol are proposed to achieve this abstraction. Support for these messages are implemented in the Astro-WISE information system and in a set of demonstrational applications.

  9. Query Driven Visualization of Astronomical Catalogs

    CERN Document Server

    Buddelmeijer, Hugo

    2011-01-01

    Interactive visualization of astronomical catalogs requires novel techniques due to the huge volumes and complex structure of the data produced by existing and upcoming astronomical surveys. The creation as well as the disclosure of the catalogs can be handled by data pulling mechanisms. These prevent unnecessary processing and facilitate data sharing by having users request the desired end products. In this work we present query driven visualization as a logical continuation of data pulling. Scientists can request catalogs in a declarative way and set process parameters directly from within the visualization. This results in profound interoperation between software with a high level of abstraction. New messages for the Simple Application Messaging Protocol are proposed to achieve this abstraction. Support for these messages are implemented in the Astro-WISE information system and in a set of demonstrational applications.

  10. Revista Mexicana de Astronomía y Astrofísica, a real option for astronomical publication

    Science.gov (United States)

    Torres-Peimbert, S.; Allen, C.

    2011-10-01

    We present statistical data about the Revista Mexicana de Astronomía y Astrofísica. We consider that this journal is well positioned in the international astronomical literature. Similarly we present information about the Serie de Conferencias, which also has a wide level of acceptance by the astronomical community.

  11. Astronomical orientations in sanctuaries of Daunia

    CERN Document Server

    Antonello, E; Sisto, A M Tunzi; LoZupone, M

    2013-01-01

    Prehistoric sanctuaries of Daunia date back several thousand years. During the Neolithic and Bronze Age the farmers in that region dug hypogea and holes whose characteristics suggest a ritual use. In the present note we summarize the results of the astronomical analysis of the orientation of the row holes in three different sites, and we point out the possible use of the setting of the stars of Centaurus. An interesting archaeological confirmation of an archaeoastronomical prediction is also reported.

  12. Analyses of GRBs on astronomical emulsions

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Hudcová, Věra; Krolupper, F.; Kroll, P.

    Melville : American Institute of Physics, 2003 - (Ricker, G.; Vanderpeck, R.), s. 523-525 - (AIP Conference proceedings.. 662). [Gamma-ray burst and afterglow astronomy 2001. Woods Hole, Massachusetts (US), 05.11.2001-09.11.2001] R&D Projects: GA ČR GA205/99/0145; GA MŠk ME 002 Institutional research plan: CEZ:AV0Z1003909 Keywords : astronomical plates * gamma ray Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  13. Encyclopedias of Astronomical Biographies - Status and Prospects --

    Science.gov (United States)

    Dick, W. R.

    Simple requests for biographies of famous astronomers can easily be satisfied. Short accounts of their lives are to be found in many books and encyclopedias. However, most of these sources are very incomplete, i. e.\\ do not provide information on less famous persons, and are not up to scientific standards. The most comprehensive sources of scientific biographies, Poggendorffs Biographisch-Literarisches Handwoerterbuch and Dictionary of Scientific Biography, are also not complete, partly not up-to-date and for most users not easily accessible. The most recent and most comprehensive dictionary of astronomical biography, containing 500 short entries, was written in Russian. Although a lot of information on biographies is available in publications, these are spread over thousands of volumes. There is no bibliography of these papers and books. During the last three years, short biographies of astronomers were also published in the World Wide Web. Some of these are on a very high scientific level. The author's collection of links to such WWW pages (http://www.astro.uni-bonn.de/~pbrosche/hist\\_astr/ ha\\_pers.html}) contains currently several thousand entries for more than 1200 persons related to the history of astronomy. This electronic ``encyclopedia'' in distributed form is now the most comprehensive and concentrated source for astronomical biographies. However, there are several problems arising from the electronic form of publication and from the uncoordinated and not always qualified efforts of the authors. The paper will discuss proposals, plans and first results of filling the gaps and increasing the quality, as well as some principal problems of writing short biographies and making them available to the public.

  14. Cave of the Astronomers at Xochicalco

    Science.gov (United States)

    Lebeuf, Arnold

    The chimney built in the roof of the artificial large cave at Xochicalco, known as "Cave of the astronomers", has been interpreted as a solar zenithal observation tube. Nevertheless, different elements and especially the latitude of the site itself led the author to present a lunar hypothesis. Precise measurements of the impact of light inside the cave show the degree of precision that can be obtained in this camera obscura.

  15. Making Access to Astronomical Software More Efficient

    OpenAIRE

    Grosbol, P.; Tody, D.

    2010-01-01

    Access to astronomical data through archives and VO is essential but does not solve all problems. Availability of appropriate software for analyzing the data is often equally important for the efficiency with which a researcher can publish results. A number of legacy systems (e.g. IRAF, MIDAS, Starlink, AIPS, Gipsy), as well as others now coming online are available but have very different user interfaces and may no longer be fully supported. Users may need multiple systems or stand-alone pac...

  16. Planar Integrated Optics and astronomical interferometry

    OpenAIRE

    Kern, Pierre; Berger, Jean-Philippe; Haguenauer, Pierre; Malbet, Fabien; Perraut, Karine

    2001-01-01

    16 pages Integrated optics (IO) is an optical technology that allows to reproduce optical circuits on a planar substrate. Since 1996, we have investigated the potentiality of IO in the framework of astronomical single mode interferometry. We review in this paper the principles of IO, the requirements for interferometry and the corresponding solutions offered by IO, the results of component characterization and the possible fields of application.

  17. An Astronomer's View of Climate Change

    CERN Document Server

    Morton, Donald C

    2014-01-01

    This paper describes some of the astronomical effects that could be important for understanding the ice ages, historic climate changes and the recent temperature increase. These include changes in the sun's luminosity, periodic changes in the earth's orbital parameters, the sun's orbit around our galaxy, the variability of solar activity and the anticorrelation of cosmic ray flux with that activity. Finally recent trends in solar activity and global temperatures are compared with the predictions of climate models.

  18. Software design for panoramic astronomical pipeline processing

    OpenAIRE

    Shamir, Lior; Nemiroff, Robert J.; Torrey, David O.; Pereira, Wellesley E.

    2005-01-01

    We describe the software requirement and design specifications for all-sky panoramic astronomical pipelines. The described software aims to meet the specific needs of super-wide angle optics, and includes cosmic-ray hit rejection, image compression, star recognition, sky opacity analysis, transient detection and a web server allowing access to real-time and archived data. The presented software is being regularly used for the pipeline processing of 11 all-sky cameras located in some of the wo...

  19. Preserving and Archiving Astronomical Photographic Plates

    Science.gov (United States)

    Castelaz, M. W.; Cline, J. D.

    2005-05-01

    Astronomical objects change with time. New observations complement past observations recorded on photographic plates. Analyses of changes provide essential routes to information about an object's formation, constitution and evolution. Preserving a century of photographic plate observations is thus of paramount importance. Plate collections are presently widely dispersed; plates may be stored in poor conditions, and are effectively inaccessible to both researchers and historians. We describe a planned project at Pisgah Astronomical Research Institute to preserve the collections of astronomical plates in the United States by gathering them into a single storage location. Collections will be sorted, cleaned, and cataloged on-line so as to provide access to researchers. Full scientific and historic use of the material then requires the observations themselves to be accessible digitally. The project's goal will be the availability of these data as a unique, fully-maintained scientific and educational resource. The new archive will support trans-disciplinary research such as the chemistry of the Earth's atmosphere, library information science, trends in local weather patterns, and impacts of urbanization on telescope use, while the hand-written observatory logs will be a valuable resource for science historians and biographers.

  20. David Gill - Magnificent and Desirable Astronomer

    CERN Document Server

    Reid, John S

    2016-01-01

    This paper was given to mark the centenary of the death of David Gill, the foremost British astronomer in the last quarter of the 19th century and into the 20th century. Gill abandoned a successful career as a clock and watchmaker. His speciality was in astrometry, an area of astronomy of both practical and scientific importance that tended to be eclipsed in the 20th century by the rise of astrophysics. As Her Majesty's Astronomer at the Cape of Good Hope for 27 years, David Gill was admired for his prolific contribution to highly accurate and trustworthy results. David Gill's collaboration was desired by leading astronomers of the day and he was the only southern hemisphere representative on the hugely important Conference Internationale des Etoiles Fondamentales of 1896. He created with Jacobus Kapetyn the first extensive star catalogue derived from photographic plates (the CPD), including over 450,000 stars. He was an initiator of the biggest multi-national and multi-observatory project of the century, tak...

  1. Astrobiology: An astronomer's perspective

    International Nuclear Information System (INIS)

    In this review we explore aspects of the field of astrobiology from an astronomical viewpoint. We therefore focus on the origin of life in the context of planetary formation, with additional emphasis on tracing the most abundant volatile elements, C, H, O, and N that are used by life on Earth. We first explore the history of life on our planet and outline the current state of our knowledge regarding the delivery of the C, H, O, N elements to the Earth. We then discuss how astronomers track the gaseous and solid molecular carriers of these volatiles throughout the process of star and planet formation. It is now clear that the early stages of star formation fosters the creation of water and simple organic molecules with enrichments of heavy isotopes. These molecules are found as ice coatings on the solid materials that represent microscopic beginnings of terrestrial worlds. Based on the meteoritic and cometary record, the process of planet formation, and the local environment, lead to additional increases in organic complexity. The astronomical connections towards this stage are only now being directly made. Although the exact details are uncertain, it is likely that the birth process of star and planets likely leads to terrestrial worlds being born with abundant water and organics on the surface

  2. AAS Publishing News: Astronomical Software Citation Workshop

    Science.gov (United States)

    Kohler, Susanna

    2015-07-01

    Do you write code for your research? Use astronomical software? Do you wish there were a better way of citing, sharing, archiving, or discovering software for astronomy research? You're not alone! In April 2015, AAS's publishing team joined other leaders in the astronomical software community in a meeting funded by the Sloan Foundation, with the purpose of discussing these issues and potential solutions. In attendance were representatives from academic astronomy, publishing, libraries, for-profit software sharing platforms, telescope facilities, and grantmaking institutions. The goal of the group was to establish “protocols, policies, and platforms for astronomical software citation, sharing, and archiving,” in the hopes of encouraging a set of normalized standards across the field. The AAS is now collaborating with leaders at GitHub to write grant proposals for a project to develop strategies for software discoverability and citation, in astronomy and beyond. If this topic interests you, you can find more details in this document released by the group after the meeting: http://astronomy-software-index.github.io/2015-workshop/ The group hopes to move this project forward with input and support from the broader community. Please share the above document, discuss it on social media using the hashtag #astroware (so that your conversations can be found!), or send private comments to julie.steffen@aas.org.

  3. GalileoMobile: Astronomical activities in schools

    Science.gov (United States)

    Dasi Espuig, Maria; Vasquez, Mayte; Kobel, Philippe

    GalileoMobile is an itinerant science education initiative run on a voluntary basis by an international team of astronomers, educators, and science communicators. Our team's main goal is to make astronomy accessible to schools and communities around the globe that have little or no access to outreach actions. We do this by performing teacher workshops, activities with students, and donating educational material. Since the creation of GalileoMobile in 2008, we have travelled to Chile, Bolivia, Peru, India, and Uganda, and worked with 56 schools in total. Our activities are centred on the GalileoMobile Handbook of Activities that comprises around 20 astronomical activities which we adapted from many different sources, and translated into 4 languages. The experience we gained in Chile, Bolivia, Peru, India, and Uganda taught us that (1) bringing experts from other countries was very stimulating for children as they are naturally curious about other cultures and encourages a collaboration beyond borders; (2) high-school students who were already interested in science were always very eager to interact with real astronomers doing research to ask for career advice; (3) inquiry-based methods are important to make the learning process more effective and we have therefore, re-adapted the activities in our Handbook according to these; (4) local teachers and university students involved in our activities have the potential to carry out follow-up activities, and examples are those from Uganda and India.

  4. Astrobiology: An astronomer's perspective

    Energy Technology Data Exchange (ETDEWEB)

    Bergin, Edwin A. [University of Michigan, Department of Astronomy, 500 Church Street, Ann Arbor, MI 48109 (United States)

    2014-12-08

    In this review we explore aspects of the field of astrobiology from an astronomical viewpoint. We therefore focus on the origin of life in the context of planetary formation, with additional emphasis on tracing the most abundant volatile elements, C, H, O, and N that are used by life on Earth. We first explore the history of life on our planet and outline the current state of our knowledge regarding the delivery of the C, H, O, N elements to the Earth. We then discuss how astronomers track the gaseous and solid molecular carriers of these volatiles throughout the process of star and planet formation. It is now clear that the early stages of star formation fosters the creation of water and simple organic molecules with enrichments of heavy isotopes. These molecules are found as ice coatings on the solid materials that represent microscopic beginnings of terrestrial worlds. Based on the meteoritic and cometary record, the process of planet formation, and the local environment, lead to additional increases in organic complexity. The astronomical connections towards this stage are only now being directly made. Although the exact details are uncertain, it is likely that the birth process of star and planets likely leads to terrestrial worlds being born with abundant water and organics on the surface.

  5. GASP-Galway astronomical Stokes polarimeter

    Directory of Open Access Journals (Sweden)

    Shearer A.

    2010-06-01

    Full Text Available The Galway Astronomical Stokes Polarimeter (GASP is an ultra-high-speed, full Stokes, astronomical imaging polarimeter based upon a Division of Amplitude Polarimeter. It has been developed to resolve extremely rapid stochastic (~ms variations in objects such as optical pulsars, magnetars and magnetic cataclysmic variables. The polarimeter has no moving parts or modulated components so the complete Stokes vector can be measured from just one exposure - making it unique to astronomy. The time required for the determination of the full Stokes vector is limited only by detector efficiency and photon fluxes. The polarimeter utilizes a modified Fresnel rhomb that acts as a highly achromatic quarter wave plate and a beamsplitter (referred to as an RBS. We present a description of how the DOAP works, some of the optical design for the polarimeter. Calibration is an important and difficult issue with all polarimeters, but particularly in astronomical polarimeters. We give a description of calibration techniques appropriate to this type of polarimeter.

  6. AWOB: A Collaborative Workbench for Astronomers

    Science.gov (United States)

    Kim, J. W.; Lemson, G.; Bulatovic, N.; Makarenko, V.; Vogler, A.; Voges, W.; Yao, Y.; Kiefl, R.; Koychev, S.

    2015-09-01

    We present the Astronomers Workbench (AWOB1), a web-based collaboration and publication platform for a scientific project of any size, developed in collaboration between the Max-Planck institutes of Astrophysics (MPA) and Extra-terrestrial Physics (MPE) and the Max-Planck Digital Library (MPDL). AWOB facilitates the collaboration between geographically distributed astronomers working on a common project throughout its whole scientific life cycle. AWOB does so by making it very easy for scientists to set up and manage a collaborative workspace for individual projects, where data can be uploaded and shared. It supports inviting project collaborators, provides wikis, automated mailing lists, calendars and event notification and has a built in chat facility. It allows the definition and tracking of tasks within projects and supports easy creation of e-publications for the dissemination of data and images and other resources that cannot be added to submitted papers. AWOB extends the project concept to larger scale consortia, within which it is possible to manage working groups and sub-projects. The existing AWOB instance has so far been limited to Max-Planck members and their collaborators, but will be opened to the whole astronomical community. AWOB is an open-source project and its source code is available upon request. We intend to extend AWOB's functionality also to other disciplines, and would greatly appreciate contributions from the community.

  7. Combined steady state and high cycle transient heat load simulation with the electron beam facility JUDITH 2

    International Nuclear Information System (INIS)

    The increasing world energy needs lead to strong efforts in today's energy R and D trying to open up new energy resources. One possible option to access energy in large scale power plants is to use the process of nuclear fusion to generate heat and, from that, electricity with conventional steam turbine technology. However, the realisation is technologically and scientifically very challenging. The heat fluxes that load the inner walls of a fusion device, especially the most severely loaded part, the divertor, are one of the issues currently being under investigation. A distinction is made between steady state heat loads (SSHLs) that are continuously active during operation and transient heat loads (THLs) that are superimposed short-time events. The potentially most harmful THLs during normal operation are type I Edge Localised Modes (ELMs). They are estimated to have a power density of 1 - 10 GWm-2 for 0.2 - 0.5 ms duration in the upcoming next step fusion experiment ITER. Because of high pulse repetition frequency more than 106 ELM events are expected during the foreseen lifetime of divertor components. However, only data regarding behaviour of materials for a low number of pulses (typically 100 - 1000) exists. This work describes the development of a procedure to simulate THLs at high repetition frequency using an electron beam facility and the tests done on tungsten and carbon-based (carbon fibre composite, CFC) plasma facing materials. The developed procedure uses a pulse frequency of 25 Hz, hence actively cooled components are necessary and were designed. A novel electron beam guidance procedure, called circular loading method, was a result of the developmental process. It was used for all later tests because it provides a stabilisation of the applied power density against test parameter fluctuations (e.g. vacuum quality). The electron beam guidance is flexible enough to provide a SSHL pattern during the interpulse time (between two successive THLs

  8. In situ investigation of the surface silvering of late Roman coins by combined use of high energy broad-beam and low energy micro-beam X-ray fluorescence techniques

    International Nuclear Information System (INIS)

    The compositional analysis of archeological metals performed with the X-ray Fluorescence technique (XRF) provides information on the ancient technology. One of the most interesting case-study concerns the techniques used by Romans for silvering the surface of coins. Different metallurgical processes have been suggested in previous studies. Recently the investigation has been addressed to the mercury-silvering and to its possible use in the mass-production of coins minted during the late period (after 294 AD). In the present paper the non-destructive investigation of the silvering process used for manufacturing the Roman nummi – the important typology of coin introduced by Diocletian in his monetary reform – is approached by the combined use of the standard X-Ray Fluorescence (XRF) and the low energy micro-X-Ray Fluorescence (LE-μXRF) portable methods. The research was focused on the systematic determination of the mercury presence in a large number of samples and on its correlation with silver in the surface of the coins. 1041 Roman nummi belonging to the Misurata Treasure were analyzed in situ, at the Leptis Magna Museum (Al Khums, Libya). The treasure, composed of about 108 thousand silvered coins, gives the unique opportunity to study the Roman coinage in a wide interval of time (about 40 years in the period 294–333 AD) and in almost all the imperial mints operating in the Roman world. - Highlights: ► Custom-building of a high energy broad-beam and a low energy micro-beam XRF ► In situ analysis of the silvering methods in late Roman nummi with plated surfaces ► The broad-beam XRF was applied for the detection of mercury traces in the coin alloy. ► The low energy micro-XRF was used to scan the surface patina of the coins. ► The correlation between mercury and silver at the coin surface was evidenced.

  9. Enhanced Management of Personal Astronomical Data with FITSManager

    CERN Document Server

    Cui, Chenzhou; Zhao, Yongheng; Kembhavi, Ajit; He, Boliang; Cao, Zihuang; Li, Jian; Nandrekar, Deoyani

    2011-01-01

    Although the roles of data centers and computing centers are becoming more and more important, and on-line research is becoming the mainstream for astronomy, individual research based on locally hosted data is still very common. With the increase of personal storage capacity, it is easy to find hundreds to thousands of FITS files in the personal computer of an astrophysicist. Because Flexible Image Transport System (FITS) is a professional data format initiated by astronomers and used mainly in the small community, data management toolkits for FITS files are very few. Astronomers need a powerful tool to help them manage their local astronomical data. Although Virtual Observatory (VO) is a network oriented astronomical research environment, its applications and related technologies provide useful solutions to enhance the management and utilization of astronomical data hosted in an astronomer's personal computer. FITSManager is such a tool to provide astronomers an efficient management and utilization of their ...

  10. Amateur astronomers in support of observing campaigns

    Science.gov (United States)

    Yanamandra-Fisher, P.

    2014-07-01

    The Pro-Am Collaborative Astronomy (PACA) project evolved from the observational campaign of C/2012 S1 or C/ISON. The success of the paradigm shift in scientific research is now implemented in other comet observing campaigns. While PACA identifies a consistent collaborative approach to pro-am collaborations, given the volume of data generated for each campaign, new ways of rapid data analysis, mining access, and storage are needed. Several interesting results emerged from the synergistic inclusion of both social media and amateur astronomers: - the establishment of a network of astronomers and related professionals that can be galvanized into action on short notice to support observing campaigns; - assist in various science investigations pertinent to the campaign; - provide an alert-sounding mechanism should the need arise; - immediate outreach and dissemination of results via our media/blogger members; - provide a forum for discussions between the imagers and modelers to help strategize the observing campaign for maximum benefit. In 2014, two new comet observing campaigns involving pro-am collaborations have been identified: (1) C/2013 A1 (C/Siding Spring) and (2) 67P/Churyumov-Gerasimenko (CG). The evolving need for individual customized observing campaigns has been incorporated into the evolution of PACA (Pro-Am Collaborative Astronomy) portal that currently is focused on comets: from supporting observing campaigns for current comets, legacy data, historical comets; interconnected with social media and a set of shareable documents addressing observational strategies; consistent standards for data; data access, use, and storage, to align with the needs of professional observers. The integration of science, observations by professional and amateur astronomers, and various social media provides a dynamic and evolving collaborative partnership between professional and amateur astronomers. The recent observation of comet 67P, at a magnitude of 21.2, from Siding

  11. Combined elemental analysis of ancient glass beads by means of ion beam, portable XRF, and EPMA techniques.

    Science.gov (United States)

    Sokaras, D; Karydas, A G; Oikonomou, A; Zacharias, N; Beltsios, K; Kantarelou, V

    2009-12-01

    Ion beam analysis (IBA)- and X-ray fluorescence (XRF)-based techniques have been well adopted in cultural-heritage-related analytical studies covering a wide range of diagnostic role, i.e., from screening purposes up to full quantitative characterization. In this work, a systematic research was carried out towards the identification and evaluation of the advantages and the limitations of laboratory-based (IBA, electron probe microanalyzer) and portable (milli-XRF and micro-XRF) techniques. The study focused on the analysis of an Archaic glass bead collection recently excavated from the city of Thebes (mainland, Greece), in order to suggest an optimized and synergistic analytical methodology for similar studies and to assess the reliability of the quantification procedure of analyses conducted in particular by portable XRF spectrometers. All the employed analytical techniques and methodologies proved efficient to provide in a consistent way characterization of the glass bead composition, with analytical range and sensitivity depending on the particular technique. The obtained compositional data suggest a solid basis for the understanding of the main technological features related to the raw major and minor materials utilized for the manufacture of the Thebian ancient glass bead collection. PMID:19821114

  12. Combined effect of pulse electron beam treatment and thin hydroxyapatite film on mechanical features of biodegradable AZ31 magnesium alloy

    Science.gov (United States)

    Surmeneva, M. A.; Tyurin, A. I.; Teresov, A. D.; Koval, N. N.; Pirozhkova, T. S.; Shuvarin, I. A.; Surmenev, R. A.

    2015-11-01

    The morphology, elemental, phase composition, nanohardness, and Young's modulus of the hydroxyapatite (HA) coating deposited via radio frequency (RF) magnetron sputtering onto the AZ31 surface were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and nanoindentationtechniques. The calcium phosphate (Ca/P) molar ratio of the HA coating deposited via RF-magnetron sputtering onto AZ31 substrates according to EDX was 1.57+0.03. The SEM experiments revealed significant differences in the morphology of the HA film deposited on untreated and treated with the pulsed electron beam (PEB) AZ31 substrate. Nanoindentation studies demonstrated significant differences in the mechanical responses of the HA film deposited on the initial and PEB-modified AZ31 substrates. The nanoindentation hardness and the Young's modulus of the HA film on the magnesium alloy modified using the PEB treatment were higher than that of the HA layer on the untreated substrate. Moreover, the HA film fabricated onto the PEB-treated surface was more resistant to plastic deformation than the same film on the untreated AZ31 surface.

  13. Detection and Removal of Artifacts in Astronomical Images

    CERN Document Server

    Desai, Shantanu; Bertin, Emmanuel; Kummel, Martin; Wetzstein, Michael

    2016-01-01

    Astronomical images from optical photometric surveys are typically contaminated with transient artifacts such as cosmic rays, satellite trails and scattered light. We have developed and tested an algorithm that removes these artifacts using a deep, artifact free, static sky coadd image built up through the median combination of point spread function (PSF) homogenized, overlapping single epoch images. Transient artifacts are detected and masked in each single epoch image through comparison with an artifact free, PSF-matched simulated image that is constructed using the PSF-corrected, model fitting catalog from the artifact free coadd image together with the position variable PSF model of the single epoch image. This approach works well not only for cleaning single epoch images with worse seeing than the PSF homogenized coadd, but also the traditionally much more challenging problem of cleaning single epoch images with better seeing. In addition to masking transient artifacts, we have developed an interpolation...

  14. An Efficient Method for Rare Spectra Retrieval in Astronomical Databases

    CERN Document Server

    Du, Changde; Yang, Haifeng; Hou, Wen; Guo, Yanxin

    2016-01-01

    One of important aims of astronomical data mining is to systematically search for specific rare objects in a massive spectral dataset, given a small fraction of identified samples with the same type. Most existing methods are mainly based on binary classification, which usually suffer from uncompleteness when the known samples are too few. While, rank-based methods would provide good solutions for such case. After investigating several algorithms, a method combining bipartite ranking model with bootstrap aggregating techniques was developed in this paper. The method was applied in searching for carbon stars in the spectral data of Sloan Digital Sky Survey (SDSS) DR10, and compared with several other popular methods used in data mining. Experimental results validate that the proposed method is not only the most effective but also less time consuming among these competitors automatically searching for rare spectra in a large but unlabelled dataset.128

  15. An Efficient Method for Rare Spectra Retrieval in Astronomical Databases

    Science.gov (United States)

    Du, Changde; Luo, Ali; Yang, Haifeng; Hou, Wen; Guo, Yanxin

    2016-03-01

    One of the most important aims of astronomical data mining is to systematically search for specific rare objects in a massive spectral data set, given a small fraction of identified samples with the same type. Most existing methods are mainly based on binary classification, which usually suffers from incompleteness when there are too few known samples. Rank-based methods could provide good solutions for such cases. After investigating several algorithms, a method combining a bipartite ranking model with bootstrap aggregating techniques was developed in this paper. The method was applied while searching for carbon stars in the spectral data of Sloan Digital Sky Survey Data Release 10 and compared with several other popular methods used for data mining. Experimental results validate that the proposed method is not only the most effective but also the least time-consuming technique among its competitors when searching for rare spectra in a large but unlabeled data set.

  16. Despite Appearances, Cosmic Explosions Have Common Origin, Astronomers Discover

    Science.gov (United States)

    2003-11-01

    A Fourth of July fireworks display features bright explosions that light the sky with different colors, yet all have the same cause. They just put their explosive energy into different colors of light. Similarly, astronomers have discovered, a variety of bright cosmic explosions all have the same origin and the same amount of total energy. This is the conclusion of an international team of astronomers that used the National Science Foundation's Very Large Array (VLA) radio telescope to study the closest known gamma-ray burst earlier this year. Artist's conception of burst Artist's Conception of Twin Jets in Energetic Cosmic Explosion CREDIT: Dana Berry, SkyWorks Digital (Click on Image for Larger Version) "For some reason we don't yet understand, these explosions put greatly varying percentages of their explosive energy into the gamma-ray portion of their output," said Dale Frail, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. That means, he said, that both strong and weak gamma-ray bursts, along with X-ray flashes, which emit almost no gamma rays, are just different forms of the same cosmic beast. The research team reported their results in the November 13 issue of the scientific journal Nature. The scientists trained the VLA on a gamma-ray burst discovered using NASA's HETE-2 satellite last March 29. This burst, dubbed GRB 030329, was the closest such burst yet seen, about 2.6 billion light-years from Earth. Because of this relative proximity, the burst was bright, with visible light from its explosion reaching a level that could be seen in amateur telescopes. As the burst faded, astronomers noted an underlying distinctive signature of a supernova explosion, confirming that the event was associated with the death of a massive star. Since 1999, astronomers have known that the strong outbursts of gamma rays, X-rays, visible light and radio waves from these bursts form beams, like those from a flashlight, rather than spreading in all directions

  17. MOPEX: a software package for astronomical image processing and visualization

    Science.gov (United States)

    Makovoz, David; Roby, Trey; Khan, Iffat; Booth, Hartley

    2006-06-01

    We present MOPEX - a software package for astronomical image processing and display. The package is a combination of command-line driven image processing software written in C/C++ with a Java-based GUI. The main image processing capabilities include creating mosaic images, image registration, background matching, point source extraction, as well as a number of minor image processing tasks. The combination of the image processing and display capabilities allows for much more intuitive and efficient way of performing image processing. The GUI allows for the control over the image processing and display to be closely intertwined. Parameter setting, validation, and specific processing options are entered by the user through a set of intuitive dialog boxes. Visualization feeds back into further processing by providing a prompt feedback of the processing results. The GUI also allows for further analysis by accessing and displaying data from existing image and catalog servers using a virtual observatory approach. Even though originally designed for the Spitzer Space Telescope mission, a lot of functionalities are of general usefulness and can be used for working with existing astronomical data and for new missions. The software used in the package has undergone intensive testing and benefited greatly from effective software reuse. The visualization part has been used for observation planning for both the Spitzer and Herschel Space Telescopes as part the tool Spot. The visualization capabilities of Spot have been enhanced and integrated with the image processing functionality of the command-line driven MOPEX. The image processing software is used in the Spitzer automated pipeline processing, which has been in operation for nearly 3 years. The image processing capabilities have also been tested in off-line processing by numerous astronomers at various institutions around the world. The package is multi-platform and includes automatic update capabilities. The software

  18. Combination of External Beam Radiotherapy (EBRT) With Intratumoral Injection of Dendritic Cells as Neo-Adjuvant Treatment of High-Risk Soft Tissue Sarcoma Patients

    Energy Technology Data Exchange (ETDEWEB)

    Finkelstein, Steven E., E-mail: steven.finkelstein@moffitt.org [H. Lee Moffitt Cancer Center, Tampa, FL (United States); Iclozan, Cristina; Bui, Marilyn M.; Cotter, Matthew J.; Ramakrishnan, Rupal; Ahmed, Jamil; Noyes, David R.; Cheong, David; Gonzalez, Ricardo J.; Heysek, Randy V.; Berman, Claudia; Lenox, Brianna C.; Janssen, William; Zager, Jonathan S.; Sondak, Vernon K.; Letson, G. Douglas; Antonia, Scott J. [H. Lee Moffitt Cancer Center, Tampa, FL (United States); Gabrilovich, Dmitry I., E-mail: dmitry.gabrilovich@moffitt.org [H. Lee Moffitt Cancer Center, Tampa, FL (United States)

    2012-02-01

    Purpose: The goal of this study was to determine the effect of combination of intratumoral administration of dendritic cells (DC) and fractionated external beam radiation (EBRT) on tumor-specific immune responses in patients with soft-tissue sarcoma (STS). Methods and Material: Seventeen patients with large (>5 cm) high-grade STS were enrolled in the study. They were treated in the neoadjuvant setting with 5,040 cGy of EBRT, split into 28 fractions and delivered 5 days per week, combined with intratumoral injection of 10{sup 7} DCs followed by complete resection. DCs were injected on the second, third, and fourth Friday of the treatment cycle. Clinical evaluation and immunological assessments were performed. Results: The treatment was well tolerated. No patient had tumor-specific immune responses before combined EBRT/DC therapy; 9 patients (52.9%) developed tumor-specific immune responses, which lasted from 11 to 42 weeks. Twelve of 17 patients (70.6%) were progression free after 1 year. Treatment caused a dramatic accumulation of T cells in the tumor. The presence of CD4{sup +} T cells in the tumor positively correlated with tumor-specific immune responses that developed following combined therapy. Accumulation of myeloid-derived suppressor cells but not regulatory T cells negatively correlated with the development of tumor-specific immune responses. Experiments with {sup 111}In labeled DCs demonstrated that these antigen presenting cells need at least 48 h to start migrating from tumor site. Conclusions: Combination of intratumoral DC administration with EBRT was safe and resulted in induction of antitumor immune responses. This suggests that this therapy is promising and needs further testing in clinical trials design to assess clinical efficacy.

  19. Combination of External Beam Radiotherapy (EBRT) With Intratumoral Injection of Dendritic Cells as Neo-Adjuvant Treatment of High-Risk Soft Tissue Sarcoma Patients

    International Nuclear Information System (INIS)

    Purpose: The goal of this study was to determine the effect of combination of intratumoral administration of dendritic cells (DC) and fractionated external beam radiation (EBRT) on tumor-specific immune responses in patients with soft-tissue sarcoma (STS). Methods and Material: Seventeen patients with large (>5 cm) high-grade STS were enrolled in the study. They were treated in the neoadjuvant setting with 5,040 cGy of EBRT, split into 28 fractions and delivered 5 days per week, combined with intratumoral injection of 107 DCs followed by complete resection. DCs were injected on the second, third, and fourth Friday of the treatment cycle. Clinical evaluation and immunological assessments were performed. Results: The treatment was well tolerated. No patient had tumor-specific immune responses before combined EBRT/DC therapy; 9 patients (52.9%) developed tumor-specific immune responses, which lasted from 11 to 42 weeks. Twelve of 17 patients (70.6%) were progression free after 1 year. Treatment caused a dramatic accumulation of T cells in the tumor. The presence of CD4+ T cells in the tumor positively correlated with tumor-specific immune responses that developed following combined therapy. Accumulation of myeloid-derived suppressor cells but not regulatory T cells negatively correlated with the development of tumor-specific immune responses. Experiments with 111In labeled DCs demonstrated that these antigen presenting cells need at least 48 h to start migrating from tumor site. Conclusions: Combination of intratumoral DC administration with EBRT was safe and resulted in induction of antitumor immune responses. This suggests that this therapy is promising and needs further testing in clinical trials design to assess clinical efficacy.

  20. Effects of combined treatments of electron-beam irradiation and addition of leek (Allium tuberosum) extract on reduction of pathogens in pork jerky.

    Science.gov (United States)

    Kang, Mingu; Kim, Hyun-Joo; Jayasena, Dinesh D; Bae, Young Sik; Yong, Hae In; Lee, Mooha; Jo, Cheorun

    2012-12-01

    This study investigated the combined effect of electron-beam irradiation and addition of leek (Allium tuberosum R.) extract on pork jerky inoculated with selected foodborne pathogens. Prepared pork jerky samples (control and samples with 1.0% leek extract) were inoculated with pathogens and subsequently irradiated at 0, 0.5, 1, 2, 3, and 4 kGy doses. In comparison with the control, samples with 1.0% leek extract showed significant reduction in the numbers of Escherichia coli, Listeria monocytogenes, and Salmonella Typhimurium. No viable counts were detected for Salmonella Typhimurium in both control and leek-extract samples, and for E. coli and L. monocytogenes in the leek-extract sample exposed to 3 kGy irradiation dose. The D(10) values for E. coli, L. monocytogenes, and Salmonella Typhimurium observed in the irradiated samples with leek extract were 0.39, 0.34, and 0.32 kGy, while the D(10) values in those without leek extract were 0.65, 0.65, and 0.39 kGy, respectively. Therefore, our results clearly showed that irradiation combined with leek extract was effective in reducing pathogens, suggesting that a low dose of irradiation combined with the addition of a natural antimicrobial agent can enhance the microbial safety and shelf-life of pork jerky. PMID:23199493

  1. Auger electron nanoscale mapping and x-ray photoelectron spectroscopy combined with gas cluster ion beam sputtering to study an organic bulk heterojunction

    International Nuclear Information System (INIS)

    The lateral and vertical distributions of organic p/n bulk heterojunctions for an organic solar cell device are, respectively, investigated using nanometer-scale Auger electron mapping and using X-ray photoelectron spectroscopy (XPS) with Ar gas cluster ion beam (GCIB) sputtering. The concentration of sulfur, present only in the p-type material, is traced to verify the distribution of p-type (donor) and n-type (acceptor) materials in the blended structure. In the vertical direction, a considerable change in atomic sulfur concentration is observed using XPS depth profiling with Ar GCIB sputtering. In addition, Auger electron mapping of sulfur reveals the lateral 2-dimensional distribution of p- and n-type materials. The combination of Auger electron mapping with Ar GCIB sputtering should thereby allow the construction of 3-dimensional distributions of p- and n-type materials in organic photovoltaic cells

  2. Qualitative and Quantitative Characterization of Porosity in a Low Porous and Low Permeable Organic Rich Shale by Combining Broad Ion Beam and Scanning Electron Microscopy (BIB-SEM)

    International Nuclear Information System (INIS)

    This contribution focuses on the characterization of porosity in low porous shale using a broad ion beam (BIB) polishing technique combined with a conventional scanning electron microscopy (SEM). Porosity was traced in certain representative elementary areas (REA) and pores detected are segmented from mosaics of secondary electron (SE) images. Traced pores could be classified into two major pore-size classes. Relative large pores (> 0.5 μm2) were found in the organic matter and matrix. They contribute strongly to the overall porosity con-tent of the shale. Nevertheless the far majority of the pores traced have equivalent radius less than 400 nm. Including the latter pore class, the imaged porosity from both samples gives similar results in the order of < 1 %. (authors)

  3. Young Astronomers' Observe with ESO Telescopes

    Science.gov (United States)

    1995-11-01

    Today, forty 16-18 year old students and their teachers are concluding a one-week, educational `working visit' to the ESO Headquarters in Garching (See ESO Press Release 14/95 of 8 November 1995). They are the winners of the Europe-wide contest `Europe Towards the Stars', organised by ESO with the support of the European Union, under the auspices of the Third European Week for Scientific and Technological Culture. From November 14-20, they have worked with professional ESO astronomers in order to get insight into the methods and principles of modern astronomy and astrophysics, as carried out at one of the world's foremost international centres. This included very successful remote observations with the ESO 3.5-m New Technology Telescope (NTT) and the 1.4-m Coude Auxiliary Telescope (CAT) via a satellite link between the ESO Headquarters and the La Silla observatory in Chile, 12,000 kilometres away. After a general introduction to modern astronomy on the first day of the visit, the participants divided into six teams, according to their interests. Some chose to observe distant galaxies, others prefered to have a closer look on binary stars, and one team decided to investigate a star which is thought to be surrounded by a proto-planetary system. Each team was supported by an experienced ESO astronomer. Then followed the observations at the remote consoles during three nights, the first at the NTT and the following at the CAT. Each team had access to the telescope during half a night. Although the work schedule - exactly as in `real' science - was quite hard, especially during the following data reduction and interpretative phase, all teams managed extremely well and in high spirits. The young astronomers' observations were favoured by excellent atmospheric conditions. At the NTT, the seeing was better than 0.5 arcsecond during several hours, an exceptional value that allows very good images to be obtained. All observations represent solid and interesting science, and

  4. Community College Class Devoted to Astronomical Research

    Science.gov (United States)

    Genet, R. M.; Genet, C. L.

    2002-05-01

    A class at a small community college, Central Arizona College, was dedicated to astronomical research. Although hands-on research is usually reserved for professionals or graduate students, and occasionally individual undergraduate seniors, we decided to introduce community college students to science by devoting an entire class to research. Nine students were formed into three closely cooperating teams. The class as a whole decided that all three teams would observe Cepheid stars photometrically using a robotic telescope at the Fairborn Observatory. Speaker-phone conference calls were made to Kenneth E. Kissell for help on Cepheid selection, Michael A. Seeds for instructions on the use of the Phoenix-10 robotic telescope, and Douglas S. Hall for assitance in selecting appropriate comparison and check stars. The students obtained critical references on past observations from Konkoly Observatory via airmail. They spent several long night sessions at our apartment compiling the data, making phase calculations, and creating graphs. Finally, the students wrote up their results for publication in a forthcoming special issue of the international journal on stellar photometry, the IAPPP Communication. We concluded that conducting team research is an excellent way to introduce community college students to science, that a class devoted to cooperation as opposed to competition was refreshing, and that group student conference calls with working astronomers were inspiring. A semester, however, is a rather short time to initiate and complete research projects. The students were Sally Baldwin, Cory Bushnell, Bryan Dehart, Pamela Frantz, Carl Fugate, Mike Grill, Jessica Harger, Klay Lapa, and Diane Wiseman. We are pleased to acknowledge the assistance provided by the astronomers mentioned above, James Stuckey (Campus Dean), and our Union Institute and University doctoral committee members Florence Pittman Matusky, Donald S. Hayes, and Karen S. Grove.

  5. Commission 5: Documentation and Astronomical Data

    Science.gov (United States)

    Ohishi, Masatoshi; Hanisch, Robert J.; Norris, Ray P.; Andernach, Heinz; Bishop, Marsha; Griffin, Elizabeth; Kembhavi, Ajit; Murphy, Tara; Pasian, Fabio

    2012-04-01

    IAU Commission 5 (http://www.nao.ac.jp/IAU/Com5/) deals with data management issues, and its working groups and task group deal specifically with information handling, with data centers and networks, with technical aspects of collection, archiving, storage and dissemination of data, with designations and classification of astronomical objects, with library services, editorial policies, computer communications, ad hoc methodologies, and with various standards, reference frames, etc. FITS (Flexible Image Transport System), the major data exchange format in astronomy, has been standardized, maintained and updated by the FITS working group under Commission 5.

  6. UNI Astronomical Observatory - OAUNI: First light

    CERN Document Server

    Pereyra, Antonio; Meza, Erick; Cori, William; Ricra, José; Zevallos, Maria Isela

    2015-01-01

    We show the actual status of the project to implement the Astronomical Observatory of the National University of Engineering (OAUNI), including its first light. The OAUNI was installed with success at the site of the Huancayo Observatory on the peruvian central Andes. At this time, we are finishing the commissioning phase which includes the testing of all the instruments: optical tube, robotic mount, CCD camera, filter wheel, remote access system, etc. The first light gathered from a stellar field was very promissory. The next step will be to start the scientific programs and to bring support to the undergraduate courses in observational astronomy at the Faculty of Sciences of UNI.

  7. Astronomical Plate Archives and Binary Blazars Studies

    Czech Academy of Sciences Publication Activity Database

    Hudec, René

    2011-01-01

    Roč. 32, 1-2 (2011), s. 91-95. ISSN 0250-6335. [Conference on Multiwavelength Variability of Blazars. Guangzhou, 22,09,2010-24,09,2010] R&D Projects: GA ČR GA205/08/1207 Grant ostatní: GA ČR(CZ) GA102/09/0997; MŠMT(CZ) ME09027 Institutional research plan: CEZ:AV0Z10030501 Keywords : astronomical plates * plate archives archives * binary blazars Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.400, year: 2011

  8. American Astronomical Society Honors NRAO Scientist

    Science.gov (United States)

    2005-01-01

    The American Astronomical Society (AAS) has awarded its prestigious George Van Biesbroeck Prize to Dr. Eric Greisen of the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico. The society cited Greisen's quarter-century as "principal architect and tireless custodian" of the Astronomical Image Processing System (AIPS), a massive software package used by astronomers around the world, as "an invaluable service to astronomy." Dr. Eric Greisen Dr. Eric Greisen CREDIT: NRAO/AUI/NSF (Click on image for larger version) The Van Biesbroeck Prize "honors a living individual for long-term extraordinary or unselfish service to astronomy, often beyond the requirements of his or her paid position." The AAS, with about 7,000 members, is the major organization of professional astronomers in North America. " The Very Large Array (VLA) is the most productive ground-based telescope in the history of astronomy, and most of the more than 10,000 observing projects on the VLA have depended upon the AIPS software to produce their scientific results," said Dr. James Ulvestad, NRAO's Director of New Mexico Operations. "This same software package also has been the principal tool for scientists using the Very Long Baseline Array and numerous other radio telescopes around the world," Ulvestad added. Greisen, who received a Ph.D in astronomy from the California Institute of Technology, joined the NRAO in 1972. He moved from the observatory's headquarters in Charlottesville, Virginia, to its Array Operations Center in Socorro in 2000. Greisen, who learned of the award in a telephone call from the AAS President, Dr. Robert Kirschner of Harvard University, said, "I'm pleased for the recognition of AIPS and also for the recognition of the contributions of radio astronomy to astronomy as a whole." He added that "it wasn't just me who did AIPS. There were many others." The AIPS software package grew out of the need for an efficient tool for producing images with the VLA, which was being

  9. Division XII: Commission 6: Astronomical Telegrams

    Science.gov (United States)

    Samus, N. N.; Yamaoka, H.; Gilmore, A. C.; Aksnes, K.; Green, D. W. E.; Marsden, B. G.; Nakano, S.; Lara, Martin; Pitjeva, Elena V.; Sphar, T.; Ticha, J.; Williams, G.

    2015-08-01

    IAU Commission 6 ``Astronomical Telegrams'' had a single business meeting during the Beijing General Assembly of the IAU. It took place on Friday, August 24, 2012. The meeting was attended by five C6 members (N. N. Samus; D. W. E. Green; S. Nakano; J. Ticha; and H. Yamaoka). Also present was Prof. F. Genova as a representative of the IAU Division B. She told the audience about the current restructuring of IAU Commissions and Divisions and consequences for the future of C6.

  10. The astronomical revolution Copernicus, Kepler, Borelli

    CERN Document Server

    Koyre, Alexandre

    2013-01-01

    Originally published in English in 1973. This volume traces the development of the revolution which so drastically altered man's view of the universe in the sixteenth and seventeenth centuries. The ""astronomical revolution"" was accomplished in three stages, each linked with the work of one man. With Copernicus, the sun became the centre of the universe. With Kepler, celestial dynamics replaced the kinematics of circles and spheres used by Copernicus. With Borelli the unification of celestial and terrestrial physics was completed by abandonment of the circle in favour the straight line to inf

  11. Contamination control of the Infrared Astronomical Satellite

    Science.gov (United States)

    Andreozzi, L. C.; Irace, W. R.; Maag, C. R.

    1980-01-01

    The Infrared Astronomical Satellite, to be launched in August 1981, will perform an all-sky survey in the 8-120 micron wavelength region. High sensitivity to thermal radiation and the low operating temperature of optics and thermal control surfaces make the IRAS telescope extremely vulnerable to contamination. Four special topics of importance are discussed in this paper: (1) deposition of atmospheric gases; (2) sighting of particles released from the satellite; (3) functions of a deployable aperture cover; and (4) degradation of a radiatively cooled sunshade from spacecraft outgassing. These topics demonstrate how mission strategy, ground cleaning and handling, and hardware design are used to avoid contamination which would degrade telescope performance.

  12. Penn State astronomical image processing system

    International Nuclear Information System (INIS)

    The needs of modern astronomy for image processing set demanding standards in simultaneously requiring fast computation speed, high-quality graphic display, large data storage, and interactive response. An innovative image processing system was designed, integrated, and used; it is based on a supermicro architecture which is tailored specifically for astronomy, which provides a highly cost-effective alternative to the traditional minicomputer installation. The paper describes the design rationale, equipment selection, and software developed to allow other astronomers with similar needs to benefit from the present experience. 9 references

  13. Sodium fluoride toxicity and its combined effect with 12C-ion beam radiation on A549 lung cancer cell line

    International Nuclear Information System (INIS)

    Sodium fluoride (NaF) is an anti-glycolytic agent (inhibits enolase) thus blocking formation of pyruvate. Not much has been documented about its radio-sensitization properties. We are trying to explore its synergism with high LET radiation to kill the cancer cells. We have determined the IC50 of NaF in A549 cell line to be 13.7 mM. A minimum dose of 1mM NaF was selected on the basis of proliferation, morphological, cell cycle studies, to be used in combination with a 12C-ion beam dose of 1 Gy. NaF is administered for 24 h prior to irradiation and then assayed for sensitivity after 24 h of post irradiation incubation. Cell growth decreased in the combination treatment in comparison to radiation alone. Cell cycle analysis reveals G2-block upon 1 Gy irradiation in addition to the DNA fragmentation in the combination treatment. Metabolic activity as measured by MTT assay increased gradually along with ROS as evident in DCFDA assay. An important observation is the significant reduction in mitochondrial membrane potential in the combination treatment compared to radiation treatment alone as observed in total fluorescence of Rhodamine 123. We, hereby, aim to minimize the radiation dose by synergizing with optimum dose of NaF which would contribute to more efficient and economical heavy ion therapy protocols. We have been able to note sensitization in A549. The mitochondrial sensitivity obtained is significant and therefore other cellular event that may lead to cell death at the given dose, therefore signifying the use of high-LET radiation, needs further exploration and is therefore under investigation. (author)

  14. Combined modality therapy for localized prostate carcinoma using Iridium-192 brachytherapy and external beam radiotherapy: results, morbidity, and the lack of value of surgical lymph node staging

    International Nuclear Information System (INIS)

    Purpose/Objective: (1) To quantitate the morbidity and 5 and 10 year bNED survival of Ir-192 temporary implant combined with external beam radiotherapy in the treatment of clinically localized Prostate Carcinoma. (2) To determine the need for nodal staging prior to implant. Materials and Methods: 335 consecutively treated patients seen between 8/17/84 and 8/13/93 were analyzed. All patents had retropertoneal nodal dissection and were implanted with Ir-192 using the Syed-Neblett template. Thirteen percent who completed treatment per protocol were found to have microscopically involved nodes on permanent section. 277 patients had completed the entire treatment protocol and had at least 2 years follow-up with DRE and serial serum PSAs. All patients were evaluated for morbidity using the standard RTOG morbidity scales. The bNED survival was determined using Kaplan-Meier methods with a non-rising PSA value of < 1.0 used as an indicator of disease control. All patients received 30 Gy in 50 hrs. to the implant volume, followed in two weeks by 34.2 Gy external beam (19 fx/ 25 days). The median follow up for the group is 55 months. Results: Morbidity: 69.2% of the patients experienced no reportable morbidity. Urinary morbidity was usually transient and mild (Grade 1 or 2 in 9.7%). 4.9 % experienced grade 3 urinary complaints (6.6% stress incontinence) and the incidence of grade 4 urinary complaints was 0.6%. Urinary complications were 2.5 times more common in patients who had previously undergone a TURP. Rectal complications were mild or moderate in 10.5% and usually consisted of asymptomatic rectal bleeding (6.9%). Severe rectal ulcer requiring temporary colostomy occurred in 1.4% and always healed after colostomy. Other morbidity consisted of mild, self-limited edema (2.1%). One patient had persistent edema post treatment, and there was one death from a CVA perioperatively (0.3%). 75% of patients who were potent prior to treatment maintained useful sexual function post

  15. Relativistic scaling of astronomical quantities and the system of astronomical units

    Science.gov (United States)

    Klioner, S. A.

    2008-02-01

    Context: For relativistic modeling of high-accuracy astronomical data, several time scales are used: barycentric and geocentric coordinate times (TCB and TCG) and two additional time scales (TDB and TT), which are defined as linear functions of TCB and TCG, respectively. Aims: The paper is devoted to a concise, but still detailed, explanation of the reasons and the implications of the relativistic scalings of astronomical quantities induced by the time scales TDB and TT. Methods: We consequently distinguish between quantities and their numerical values expressed in some units. Results: It is argued that the scaled time scales, the scaled spatial coordinates, and the scaled masses should be considered as distinct quantities that can be expressed themselves in any units and not as numerical values of the same quantities expressed in some different, non-SI units (“TDB units” and “TT units”). Along the same lines, the system of astronomical units is discussed in the relativistic framework. The whole freedom in the definitions of the systems of astronomical units for TCB and TDB is demonstrated. A number of possible ways to freeze the freedom are shown and discussed. It is argued that in the future one should think about converting AU into a defined quantity by fixing its value in SI meters.

  16. In situ investigation of the surface silvering of late Roman coins by combined use of high energy broad-beam and low energy micro-beam X-ray fluorescence techniques

    Energy Technology Data Exchange (ETDEWEB)

    Romano, F.P., E-mail: romanop@lns.infn.it [IBAM, CNR, Via Biblioteca 4, 95124 Catania (Italy); LNS, INFN, Via S. Sofia 62, 95123 Catania (Italy); Garraffo, S. [ITABC, CNR, Via Salaria km 29.300, 00016 Monterotondo, Roma (Italy); Pappalardo, L. [IBAM, CNR, Via Biblioteca 4, 95124 Catania (Italy); LNS, INFN, Via S. Sofia 62, 95123 Catania (Italy); Rizzo, F. [LNS, INFN, Via S. Sofia 62, 95123 Catania (Italy); Dipartimento di Fisica e Astronomia, Universita di Catania, Via S. Sofia 64, 95123 Catania (Italy)

    2012-07-15

    The compositional analysis of archeological metals performed with the X-ray Fluorescence technique (XRF) provides information on the ancient technology. One of the most interesting case-study concerns the techniques used by Romans for silvering the surface of coins. Different metallurgical processes have been suggested in previous studies. Recently the investigation has been addressed to the mercury-silvering and to its possible use in the mass-production of coins minted during the late period (after 294 AD). In the present paper the non-destructive investigation of the silvering process used for manufacturing the Roman nummi - the important typology of coin introduced by Diocletian in his monetary reform - is approached by the combined use of the standard X-Ray Fluorescence (XRF) and the low energy micro-X-Ray Fluorescence (LE-{mu}XRF) portable methods. The research was focused on the systematic determination of the mercury presence in a large number of samples and on its correlation with silver in the surface of the coins. 1041 Roman nummi belonging to the Misurata Treasure were analyzed in situ, at the Leptis Magna Museum (Al Khums, Libya). The treasure, composed of about 108 thousand silvered coins, gives the unique opportunity to study the Roman coinage in a wide interval of time (about 40 years in the period 294-333 AD) and in almost all the imperial mints operating in the Roman world. - Highlights: Black-Right-Pointing-Pointer Custom-building of a high energy broad-beam and a low energy micro-beam XRF Black-Right-Pointing-Pointer In situ analysis of the silvering methods in late Roman nummi with plated surfaces Black-Right-Pointing-Pointer The broad-beam XRF was applied for the detection of mercury traces in the coin alloy. Black-Right-Pointing-Pointer The low energy micro-XRF was used to scan the surface patina of the coins. Black-Right-Pointing-Pointer The correlation between mercury and silver at the coin surface was evidenced.

  17. Digitization of Archives of Astronomical Plates

    Science.gov (United States)

    Omizzolo, Alessandro; Cesare, Barbieri; Blanco, Carlo; Bucciarelli, Beatrice; di Paola, Andrea; Nesci, Roberto

    The photographic plate archives of telescopes around the world contain a veritable treasury of astronomical data. Unfortunately the emulsion is a volatile support and full exploitation of the scientific content is more and more difficult. A large-scale two-year project to digitize the archive of plates of the Italian Astronomical Observatories and of the Specola Vaticana has been started in 2002 with funds from the Ministry of the University and Research following a pilot program funded by the University of Padova in 2001. Identical systems composed by a high quality commercial scanner plus dedicated personal computers and acquisition software (developed initially at DLR Berlin) have been installed in all participating Institutes. Three main goals make up the total project: to provide high quality photometric sequences with the Campo Imperatore telescopes to be used on the scanned plates to perform astrometric measures taking advantage of the large span of time covered by the plates and to distribute the digitized information to all interested researchers via the international Web. This paper presents some of the activities carried out and results obtained so far

  18. Powerful Radio Burst Indicates New Astronomical Phenomenon

    Science.gov (United States)

    2007-09-01

    Astronomers studying archival data from an Australian radio telescope have discovered a powerful, short-lived burst of radio waves that they say indicates an entirely new type of astronomical phenomenon. Region of Strong Radio Burst Visible-light (negative greyscale) and radio (contours) image of Small Magellanic Cloud and area where burst originated. CREDIT: Lorimer et al., NRAO/AUI/NSF Click on image for high-resolution file ( 114 KB) "This burst appears to have originated from the distant Universe and may have been produced by an exotic event such as the collision of two neutron stars or the death throes of an evaporating black hole," said Duncan Lorimer, Assistant Professor of Physics at West Virginia University (WVU) and the National Radio Astronomy Observatory (NRAO). The research team led by Lorimer consists of Matthew Bailes of Swinburne University in Australia, Maura McLaughlin of WVU and NRAO, David Narkevic of WVU, and Fronefield Crawford of Franklin and Marshall College in Lancaster, Pennsylvania. The astronomers announced their findings in the September 27 issue of the online journal Science Express. The startling discovery came as WVU undergraduate student David Narkevic re-analyzed data from observations of the Small Magellanic Cloud made by the 210-foot Parkes radio telescope in Australia. The data came from a survey of the Magellanic Clouds that included 480 hours of observations. "This survey had sought to discover new pulsars, and the data already had been searched for the type of pulsating signals they produce," Lorimer said. "We re-examined the data, looking for bursts that, unlike the usual ones from pulsars, are not periodic," he added. The survey had covered the Magellanic Clouds, a pair of small galaxies in orbit around our own Milky Way Galaxy. Some 200,000 light-years from Earth, the Magellanic Clouds are prominent features in the Southern sky. Ironically, the new discovery is not part of these galaxies, but rather is much more distant

  19. Astronomical Surveys, Catalogs, Databases, and Archives

    Science.gov (United States)

    Mickaelian, A. M.

    2016-06-01

    All-sky and large-area astronomical surveys and their cataloged data over the whole range of electromagnetic spectrum are reviewed, from γ-ray to radio, such as Fermi-GLAST and INTEGRAL in γ-ray, ROSAT, XMM and Chandra in X-ray, GALEX in UV, SDSS and several POSS I and II based catalogues (APM, MAPS, USNO, GSC) in optical range, 2MASS in NIR, WISE and AKARI IRC in MIR, IRAS and AKARI FIS in FIR, NVSS and FIRST in radio and many others, as well as most important surveys giving optical images (DSS I and II, SDSS, etc.), proper motions (Tycho, USNO, Gaia), variability (GCVS, NSVS, ASAS, Catalina, Pan-STARRS) and spectroscopic data (FBS, SBS, Case, HQS, HES, SDSS, CALIFA, GAMA). Most important astronomical databases and archives are reviewed as well, including Wide-Field Plate DataBase (WFPDB), ESO, HEASARC, IRSA and MAST archives, CDS SIMBAD, VizieR and Aladin, NED and HyperLEDA extragalactic databases, ADS and astro-ph services. They are powerful sources for many-sided efficient research using Virtual Observatory tools. Using and analysis of Big Data accumulated in astronomy lead to many new discoveries.

  20. Automated object detection for astronomical images

    Science.gov (United States)

    Orellana, Sonny; Zhao, Lei; Boussalis, Helen; Liu, Charles; Rad, Khosrow; Dong, Jane

    2005-10-01

    Sponsored by the National Aeronautical Space Association (NASA), the Synergetic Education and Research in Enabling NASA-centered Academic Development of Engineers and Space Scientists (SERENADES) Laboratory was established at California State University, Los Angeles (CSULA). An important on-going research activity in this lab is to develop an easy-to-use image analysis software with the capability of automated object detection to facilitate astronomical research. This paper presented a fast object detection algorithm based on the characteristics of astronomical images. This algorithm consists of three steps. First, the foreground and background are separated using histogram-based approach. Second, connectivity analysis is conducted to extract individual object. The final step is post processing which refines the detection results. To improve the detection accuracy when some objects are blocked by clouds, top-hat transform is employed to split the sky into cloudy region and non-cloudy region. A multi-level thresholding algorithm is developed to select the optimal threshold for different regions. Experimental results show that our proposed approach can successfully detect the blocked objects by clouds.

  1. Astronomers Make First Images With Space Radio Telescope

    Science.gov (United States)

    1997-07-01

    Marking an important new milestone in radio astronomy history, scientists at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, have made the first images using a radio telescope antenna in space. The images, more than a million times more detailed than those produced by the human eye, used the new Japanese HALCA satellite, working in conjunction with the National Science Foundation's (NSF) Very Long Baseline Array (VLBA) and Very Large Array (VLA) ground-based radio telescopes. The landmark images are the result of a long-term NRAO effort supported by the National Aeronautics and Space Administration (NASA). "This success means that our ability to make detailed radio images of objects in the universe is no longer limited by the size of the Earth," said NRAO Director Paul Vanden Bout. "Astronomy's vision has just become much sharper." HALCA, launched on Feb. 11 by Japan's Institute of Space and Astronautical Science (ISAS), is the first satellite designed for radio astronomy imaging. It is part of an international collaboration led by ISAS and backed by NRAO; Japan's National Astronomical Observatory; NASA's Jet Propulsion Laboratory (JPL); the Canadian Space Agency; the Australia Telescope National Facility; the European VLBI Network and the Joint Institute for Very Long Baseline Interferometry in Europe. On May 22, HALCA observed a distant active galaxy called PKS 1519-273, while the VLBA and VLA also observed it. Data from the satellite was received by a tracking station at the NRAO facility in Green Bank, West Virginia. Tape-recorded data from the satellite and from the radio telescopes on the ground were sent to NRAO's Array Operations Center (AOC) in Socorro, NM. In Socorro, astronomers and computer scientists used a special-purpose computer to digitally combine the signals from the satellite and the ground telescopes to make them all work together as a single, giant radio telescope. This dedicated machine, the VLBA Correlator, built as

  2. Optical and structural properties of microcrystalline GaN on an amorphous substrate prepared by a combination of molecular beam epitaxy and metal–organic chemical vapor deposition

    Science.gov (United States)

    Min, Jung-Wook; Hwang, Hyeong-Yong; Kang, Eun-Kyu; Park, Kwangwook; Kim, Ci-Hyun; Lee, Dong-Seon; Jho, Young-Dahl; Bae, Si-Young; Lee, Yong-Tak

    2016-05-01

    Microscale platelet-shaped GaN grains were grown on amorphous substrates by a combined epitaxial growth method of molecular beam epitaxy (MBE) and metal–organic chemical vapor deposition (MOCVD). First, MBE GaN was grown on an amorphous substrate as a pre-orienting layer and its structural properties were investigated. Second, MOCVD grown GaN samples using the different growth techniques of planar and selective area growth (SAG) were comparatively investigated by transmission electron microscopy (TEM), cathodoluminescence (CL), and photoluminescence (PL). In MOCVD planar GaN, strong bound exciton peaks dominated despite the high density of the threading dislocations (TDs). In MOCVD SAG GaN, on the other hand, TDs were clearly reduced with bending, but basal stacking fault (BSF) PL peaks were observed at 3.42 eV. The combined epitaxial method not only provides a deep understanding of the growth behavior but also suggests an alternative approach for the growth of GaN on amorphous substances.

  3. The distribution of InCl sub x compounds in model polymeric LEDs A combined low and high-energy ion beam analysis study

    CERN Document Server

    Reijme, M A; Simons, D P L; Schok, M; Ijzendoorn, L J V; Brongersma, H H; De Voigt, M J A

    2002-01-01

    A combination of low- and high-energy ion beam analysis techniques was used to determine the distribution of indium chloride compounds in model polymeric light-emitting diodes (p-LEDs). Parts of polymeric LEDs (polydialkoxyphenylenevinylene (OC sub 1 C sub 1 sub 0 -PPV) on indium-tin-oxide (ITO) substrates) were exposed to a HCl/Ar flow to simulate the processes occurring during conversion of precursor PPVs and acid treatment of polymers. Samples with variable exposure times as well as pristine samples were studied with Rutherford backscattering spectrometry (RBS), low energy ion scattering (LEIS), X-ray photoelectron spectroscopy (XPS) and particle induced X-ray emission (PIXE). The RBS measurements show that after HCl exposure indium is distributed throughout the OC sub 1 C sub 1 sub 0 -PPV layer. LEIS and XPS measurements indicate that the indium and chlorine are present at the outermost surface of the OC sub 1 C sub 1 sub 0 -PPV layer. PIXE measurements in combination with the RBS data demonstrate that th...

  4. Optical and Structural Properties of Microcrystalline GaN on an Amorphous Substrate Prepared by a Combination of Molecular Beam Epitaxy and Metal-Organic Chemical Vapor Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Min, Jung-Wook; Hwang, Hyeong-Yong; Kang, Eun-Kyu; Park, Kwangwook; Kim, Ci-Hyun; Lee, Dong-Seon; Jho, Young-Dahl; Bae, Si-Young; Lee, Yong-Tak

    2016-05-01

    Microscale platelet-shaped GaN grains were grown on amorphous substrates by a combined epitaxial growth method of molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). First, MBE GaN was grown on an amorphous substrate as a pre-orienting layer and its structural properties were investigated. Second, MOCVD grown GaN samples using the different growth techniques of planar and selective area growth (SAG) were comparatively investigated by transmission electron microscopy (TEM), cathodoluminescence (CL), and photoluminescence (PL). In MOCVD planar GaN, strong bound exciton peaks dominated despite the high density of the threading dislocations (TDs). In MOCVD SAG GaN, on the other hand, TDs were clearly reduced with bending, but basal stacking fault (BSF) PL peaks were observed at 3.42 eV. The combined epitaxial method not only provides a deep understanding of the growth behavior but also suggests an alternative approach for the growth of GaN on amorphous substances.

  5. Increased radiographic contrast and dynamic range by combining a rapid multiple scanning beam device with a wide latitude receptor and digital enhancement

    International Nuclear Information System (INIS)

    The Rotating Aperture Wheel (RAW) rapid multiple scanning beam device is demonstrating marked contrast improvement in initial clinical trials. Although the RAW device is well suited to the short exposure time requirements of chest radiography, such clinical application has not as yet been attempted because the RAW's efficient scatter reduction only accentuates the inherent dynamic range problem. If a large dynamic range receptor, such as very wide latitude film or a storage phosphor, were used in combination with the RAW and the resulting images were digitally contrast enhanced, a higher signal to noise ratio could be realized across the full range of required exposure in lung, subdiaphragmatic, and mediastinal fields. The authors recently began such a study using a system combining the RAW, wide latitute film, and film digitization with scanning microdensitometer facilities for evaluating images of a chest phantom. Computer enhanced RAW images compared to those obtained using a conventional 12:1 grid show: a) no loss in feature identification in the lung field, b) better visualization of low contrast nodules as well as rib detail in the subdiaphragmatic region, and c) generally better contrast in the mediastinal region. The results clearly encourage further quantitative studies of phantoms as well as preparation for clinical application using larger image matrices

  6. ttH, H → WW(*) analysis at Atlas, LHC and Very Low Energy electron studies of 2004 combined test beam

    International Nuclear Information System (INIS)

    The Large Hadron Collider(LHC) at CERN is a proton-proton collider with a designed center of mass energy of 14 TeV. ATLAS is a general purpose particle detector located at one of the colliding point of the LHC. Using ATLAS Computing System Commissioning (CSC) Monte Carlo full simulation data of the tt-bar H, H → WW* channel, this thesis studies the feasibility of measuring top-quark Yukawa Coupling up to 30 fb-1 integrated luminosity, within the intermediate Higgs mass range from 120 to 200 GeV. For the first time, trigger, pileup effects as well as all possible systematic uncertainties are extensively studied. For a Higgs mass of 160 GeV, with the detailed systematics uncertainties studied, the signal significance is shown to exceed 2σ by combining 2 leptons and 3 leptons final states together. The combined branching ratio of σtt-barH*BRH→WW(*) can reach an accuracy of 47%, and gives important information on the top quark Yukawa Coupling. This is the first study of the tt-bar H, H → WW* channel based on full simulation data, including a complete and detailed study of the systematic uncertainties. The most difficult part of the tt-bar H, H → WW* analysis is to extract signal from an abundant background since the total cross section of signal is only 0.1% of the main background. Moreover, signals have a complex final state of at least 4 jets, 2 leptons, 2 neutrinos, making the Higgs mass reconstruction very difficult. Lepton isolation is one of the most powerful method to suppress reducible backgrounds. This thesis develops a special Cone Isolation procedure, which suppress by a factor 5 the main tt-bar background. Lepton energy scale uncertainty is one of the important systematics for the tt-bar H, H → WW* analysis. A good linearity of Very Low Energy (VLE) electrons can improve the performance of estimating electron energy scale. The second part of this thesis presents a study of the linearity of VLE electron from 2004 ATLAS Combined Test Beam (CTB

  7. Grid-Enabled Interactive Data Language for Astronomical Data Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Grid technologies provide a valuable solution for data intensive scientific applications but are not readily available for astronomical data and Interactive Data...

  8. The application of artificial intelligence to astronomical scheduling problems

    Science.gov (United States)

    Johnston, Mark D.

    1992-01-01

    Efficient utilization of expensive space- and ground-based observatories is an important goal for the astronomical community; the cost of modern observing facilities is enormous, and the available observing time is much less than the demand from astronomers around the world. The complexity and variety of scheduling constraints and goals has led several groups to investigate how artificial intelligence (AI) techniques might help solve these kinds of problems. The earliest and most successful of these projects was started at Space Telescope Science Institute in 1987 and has led to the development of the Spike scheduling system to support the scheduling of Hubble Space Telescope (HST). The aim of Spike at STScI is to allocate observations to timescales of days to a week observing all scheduling constraints and maximizing preferences that help ensure that observations are made at optimal times. Spike has been in use operationally for HST since shortly after the observatory was launched in Apr. 1990. Although developed specifically for HST scheduling, Spike was carefully designed to provide a general framework for similar (activity-based) scheduling problems. In particular, the tasks to be scheduled are defined in the system in general terms, and no assumptions about the scheduling timescale are built in. The mechanisms for describing, combining, and propagating temporal and other constraints and preferences are quite general. The success of this approach has been demonstrated by the application of Spike to the scheduling of other satellite observatories: changes to the system are required only in the specific constraints that apply, and not in the framework itself. In particular, the Spike framework is sufficiently flexible to handle both long-term and short-term scheduling, on timescales of years down to minutes or less. This talk will discuss recent progress made in scheduling search techniques, the lessons learned from early HST operations, the application of Spike

  9. Lossless Astronomical Image Compression and the Effects of Random Noise

    Science.gov (United States)

    Pence, William

    2009-01-01

    In this paper we compare a variety of modern image compression methods on a large sample of astronomical images. We begin by demonstrating from first principles how the amount of noise in the image pixel values sets a theoretical upper limit on the lossless compression ratio of the image. We derive simple procedures for measuring the amount of noise in an image and for quantitatively predicting how much compression will be possible. We then compare the traditional technique of using the GZIP utility to externally compress the image, with a newer technique of dividing the image into tiles, and then compressing and storing each tile in a FITS binary table structure. This tiled-image compression technique offers a choice of other compression algorithms besides GZIP, some of which are much better suited to compressing astronomical images. Our tests on a large sample of images show that the Rice algorithm provides the best combination of speed and compression efficiency. In particular, Rice typically produces 1.5 times greater compression and provides much faster compression speed than GZIP. Floating point images generally contain too much noise to be effectively compressed with any lossless algorithm. We have developed a compression technique which discards some of the useless noise bits by quantizing the pixel values as scaled integers. The integer images can then be compressed by a factor of 4 or more. Our image compression and uncompression utilities (called fpack and funpack) that were used in this study are publicly available from the HEASARC web site.Users may run these stand-alone programs to compress and uncompress their own images.

  10. The feasibility and safety of high-intensity focused ultrasound combined with low-dose external beam radiotherapy as supplemental therapy for advanced prostate cancer following hormonal therapy

    Institute of Scientific and Technical Information of China (English)

    Rui-Yi Wu; Guo-Min Wang; Lei Xu; Bo-Heng Zhang; Ye-Qing Xu; Zhao-Chong Zeng; Bing Chen

    2011-01-01

    The aim of this study was to investigate the feasibility and safety of high-intensity focused ultrasound (HIFU) combined with (+) low-dose external beam radiotherapy (LRT) as supplemental therapy for advanced prostate cancer (PCa) following hormonal therapy (HT). Our definition of HIFU+LRT refers to treating primary tumour lesions with HIFU in place of reduced field boost irradiation to the prostate, while retaining four-field box irradiation to the pelvis in conventional-dose external beam radiotherapy (CRT). We performed a prospective, controlled and non-randomized study on 120 patients with advanced PCa after HT who received HIFU, CRT, HIFU+LRT and HT alone, respectively. CT/MR imaging showed the primary tumours and pelvic lymph node metastases visibly shrank or even disappeared after HIFU+LRT treatment. There were significant differences among four groups with regard to overall survival (OS) and disease-specific survival (DSS) curves (P=0.018 and 0.015). Further comparison between each pair of groups suggested that the long-term DSS of the HIFU+LRT group was higher than those of the other three groups, but there was no significant difference between the HIFU+LRT group and the CRT group. Multivariable Cox's proportional hazard model showed that both HIFU+LRT and CRT were independently associated with DSS (P=0.001 and 0.035) and had protective effects with regard to the risk of death. Compared with CRT, HIFU+LRT significantly decreased incidences of radiation-related late gastrointestinal (GI) and genitourinary (GU) toxicity grade ≥II. In conclusion, long-term survival of patients with advanced PCa benefited from strengthening local control of primary tumour and regional lymph node metastases after HT. As an alternative to CRT, HIFU+LRT showed good efficacy and better safety.

  11. Combined infrared multiphoton dissociation and electron capture dissociation with a hollow electron beam in Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Tsybin, Youri O; Witt, Matthias; Baykut, Gökhan; Kjeldsen, Frank; Håkansson, Per

    2003-01-01

    An electron injection system based on an indirectly heated ring-shaped dispenser cathode has been developed and installed in a 7 Tesla Fourier transform ion cyclotron resonance (FTICR) mass spectrometer. This new hardware design allows high-rate electron capture dissociation (ECD) to be carried out by a hollow electron beam coaxial with the ion cyclotron resonance (ICR) trap. Infrared multiphoton dissociation (IRMPD) can also be performed with an on-axis IR-laser beam passing through a hole at the centre of the dispenser cathode. Electron and photon irradiation times of the order of 100 ms are required for efficient ECD and IRMPD, respectively. As ECD and IRMPD generate fragments of different types (mostly c, z and b, y, respectively), complementary structural information that improves the characterization of peptides and proteins by FTICR mass spectrometry can be obtained. The developed technique enables the consecutive or simultaneous use of the ECD and IRMPD methods within a single FTICR experimental sequence and on the same ensemble of trapped ions in multistage tandem (MS/MS/MS or MS(n)) mass spectrometry. Flexible changing between ECD and IRMPD should present advantages for the analysis of protein digests separated by liquid chromatography prior to FTICRMS. Furthermore, ion activation by either electron or laser irradiation prior to, as well as after, dissociation by IRMPD or ECD increases the efficiency of ion fragmentation, including the w-type fragment ion formation, and improves sequencing of peptides with multiple disulfide bridges. The developed instrumental configuration is essential for combined ECD and IRMPD on FTICR mass spectrometers with limited access into the ICR trap. PMID:12872281

  12. The Planetarium and the Astronomer (An Overview)

    Science.gov (United States)

    Petersen, Carolyn Collins

    1995-05-01

    The science of astronomy is one of the most accessible of the so-called "hard" sciences. Most people are familiar with some sky phenomena, and do not feel threatened at the prospect of learning more about the stars and planets. In the media, some of the best-known scientists are astronomers, and programs about astronomy tend to gather appreciatively large audiences. Planetarium facilities are a very special form of science media, with the fortunate task of presenting astronomy to the public. Like science writers, planetarium professionals take complex science information and make it accessible to the public with a variety of audio-visual techniques. Because many planetarium professionals have science backgrounds as well as educational training, they have an advantage over traditional media practitioners, who -- except for a few notable exceptions -- do not always have the luxury of a science background when it comes to writing about science. The unique background of the planetarian, however, builds a logical and natural link between astronomers and the public. This paper summarizes the wide variety of ways in which planetaria disseminate astronomy information -- ranging from live public lectures, to "astronomy updates", to hands-on activities for school children, and professionally-produced multi-media programs created especially for the needs of the domed theater. It ends with a few broad suggestions about possible roles for astronomers in any or all of these activities. Carolyn Collins Petersen has been a writer and producer of planetarium programs since 1980. Her programs have appeared in more than 500 facilities around the world. Her print work has appeared in the Denver Post, Sky and Telescope, Astronomy Magazine, and the Griffith Observer. She is the lead author of the upcoming book "Hubble Vision: Science With the Hubble Space Telescope" (due out from Cambridge University Press in Fall, 1995). Petersen has won several awards for her work. She is also a

  13. Beam-beam effects

    Energy Technology Data Exchange (ETDEWEB)

    Zholents, A.

    1994-12-01

    The term beam-beam effects is usually used to designate different phenomena associated with interactions of counter-rotating beams in storage rings. Typically, the authors speak about beam-beam effects when such interactions lead to an increase of the beam core size or to a reduction of the beam lifetime or to a growth of particle`s population in the beam halo and a correspondent increase of the background. Although observations of beam-beam effects are very similar in most storage rings, it is very likely that every particular case is largely unique and machine-dependent. This constitutes one of the problems in studying the beam-beam effects, because the experimental results are often obtained without characterizing a machine at the time of the experiment. Such machine parameters as a dynamic aperture, tune dependencies on amplitude of particle oscillations and energy, betatron phase advance between the interaction points and some others are not well known, thus making later analysis uncertain. The authors begin their discussion with demonstrations that beam-beam effects are closely related to non linear resonances. Then, they will show that a non linearity of the space charge field is responsible for the excitation of these resonances. After that, they will consider how beam-beam effects could be intensified by machine imperfections. Then, they will discuss a leading mechanism for the formation of the beam halo and will describe a new technique for beam tails and lifetime simulations. They will finish with a brief discussion of the coherent beam-beam effects.

  14. Combined dose and geometry correction (DMG) for low energy multi electron beam lithography (5kV): application to the 16nm node

    Science.gov (United States)

    Martin, Luc; Manakli, Serdar; Bayle, Sebastien; Belledent, Jérôme; Soulan, Sebastien; Wiedemann, Pablo; Farah, Abdi; Schiavone, Patrick

    2012-03-01

    Lithography faces today many challenges to meet the ITRS road-map. 193nm is still today the only existing industrial option to address high volume production for the 22nm node. Nevertheless to achieve such a resolution, double exposure is mandatory for critical level patterning. EUV lithography is still challenged by the availability of high power source and mask defectivity and suffers from a high cost of ownership perspective. Its introduction is now not foreseen before 2015. Parallel to these mask-based technologies, maskless lithography regularly makes significant progress in terms of potential and maturity. The massively parallel e-beam solution appears as a real candidate for high volume manufacturing. Several industrial projects are under development, one in the US, with the KLA REBL project and two in Europe driven by IMS Nanofabrication (Austria; MAPPER (The Netherlands). Among the developments to be performed to secure the takeoff of the multi-beam technology, the availability of a rapid and robust data treatment solution will be one of the major challenges. Within this data preparation flow, advanced proximity effect corrections must be implemented to address the 16nm node and below. This paper will detail this process and compare correction strategies in terms of robustness and accuracy. It will be based on results obtained using a MAPPER tool within the IMAGINE program driven by CEA-LETI, in Grenoble, France. All proximity effects corrections and the dithering step were performed using the software platform Inscale® from Aselta Nanographics. One important advantage of Inscale® is the ability to combine both model based dose and geometry adjustment to accurately pattern critical features. The paper will focus on the advantage of combining those two corrections at the 16nm node instead of using only geometry corrections. Thanks to the simulation capability of Inscale®, pattern fidelity and correction robustness will be evaluated and compared between

  15. Using the Galileoscope in astronomical observations

    CERN Document Server

    Oliveira, V A

    2015-01-01

    This project aims to attract school students and teachers from the state education system from Ca\\c{c}apava do Sul - RS to Sciences and specially to Astronomy. We made astronomical observations using a Galileoscope choosing the Moon as a primary target. We also observed others objects that present high brightness in the night sky. The selection of targets, and their identification during the observations were carried out by a free software of planetary simulation, Stellarium. The results were in qualitative form and they show the great interest demonstrated by those participating in the project. Furthermore, this project helped to improve the understanding of the physical proprieties of the night sky objects (e.g. color). Finally, the project has showed that using a simple equipment and of relatively low cost it is possible to bring more people, specially the young students, to the Science World and to Astronomy.

  16. AstroVis: Visualizing astronomical data cubes

    Science.gov (United States)

    Finniss, Stephen; Tyler, Robin; Questiaux, Jacques

    2016-08-01

    AstroVis enables rapid visualization of large data files on platforms supporting the OpenGL rendering library. Radio astronomical observations are typically three dimensional and stored as data cubes. AstroVis implements a scalable approach to accessing these files using three components: a File Access Component (FAC) that reduces the impact of reading time, which speeds up access to the data; the Image Processing Component (IPC), which breaks up the data cube into smaller pieces that can be processed locally and gives a representation of the whole file; and Data Visualization, which implements an approach of Overview + Detail to reduces the dimensions of the data being worked with and the amount of memory required to store it. The result is a 3D display paired with a 2D detail display that contains a small subsection of the original file in full resolution without reducing the data in any way.

  17. Die Gerling Sternwarte (Gerling Astronomical Observatory)

    CERN Document Server

    Schrimpf, Andreas

    2015-01-01

    Christian Ludwig Gerling's 1817 appointment as Professor for Mathematics, Physics and Astronomy resulted in the foundation of the Mathematical and Physical Institute of the Philipps University. In 1838, Gerling moved onto new premises in the main building of the former D\\"ornberger Hof in Renthof Street where the Philipps University's astronomical observatory was installed in the upper part of the old tower in 1841. The most important device at that time was a transit instrument which served to measure the transit times of stars in the meridian. Precise alignment required the use of a meridian stone, an artificial point of reference exactly north of and at about four kilometers' distance from the observatory. The scientists observed planets and their moons, the asteroids that were only discovered at the beginning of the 19th century, and some fainter stars in order to improve stellar charts. The Gerling Observatory is the first place in Hesse, where positions of asteroids were read.

  18. Are Supernovae Recorded in Indigenous Astronomical Traditions?

    CERN Document Server

    Hamacher, Duane W

    2014-01-01

    Novae and supernovae are rare astronomical events that would have had an influence on the sky-watching peoples who witnessed them. Although several bright novae/supernovae have been visible during recorded human history, there are many proposed but no confirmed accounts of supernovae in oral traditions or material culture. Criteria are established for confirming novae/supernovae in oral and material culture, and claims from around the world are discussed to determine if they meet these criteria. Australian Aboriginal traditions are explored for possible descriptions of novae/supernovae. Although representations of supernovae may exist in Indigenous traditions, and an account of a nova in Aboriginal traditions has been confirmed, there are currently no confirmed accounts of supernovae in Indigenous oral or material traditions.

  19. A possible Harappan Astronomical Observatory at Dholavira

    CERN Document Server

    Vahia, Mayank N

    2013-01-01

    Astronomy arises very early in a civilization and evolves as the civilization advances. It is therefore reasonable to assume that a vibrant knowledge of astronomy would have been a feature of a civilization the size of the Harappan Civilization. We suggest that structures dedicated to astronomy existed in every major Harappan city. One such city was Dholavira, an important trading port that was located on an island in what is now the Rann of Kutch during the peak of the Harappan Civilization. We have analyzed an unusual structure at Dholavira that includes two circular rooms. Upon assuming strategically-placed holes in their ceilings we examine the internal movement of sunlight within these rooms and suggest that the larger structure of which they formed a part could have functioned as an astronomical observatory.

  20. Learning Vector Quantization for Classifying Astronomical Objects

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The sizes of astronomical surveys in different wavebands are increas-ing rapidly. Therefore, automatic classification of objects is becoming ever moreimportant. We explore the performance of learning vector quantization (LVQ) inclassifying multi-wavelength data. Our analysis concentrates on separating activesources from non-active ones. Different classes of X-ray emitters populate distinctregions of a multidimensional parameter space. In order to explore the distributionof various objects in a multidimensional parameter space, we positionally cross-correlate the data of quasars, BL Lacs, active galaxies, stars and normal galaxiesin the optical, X-ray and infrared bands. We then apply LVQ to classify them withthe obtained data. Our results show that LVQ is an effective method for separatingAGNs from stars and normal galaxies with multi-wavelength data.

  1. INTEGRAL PROGRAMME OF BASIC ASTRONOMIC LITERACY DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    H. Tignanelli

    2009-01-01

    Full Text Available We discuss the development and optimization of an ongoing educational project involving the whole population of the province of San Luis, Argentina. The core of the project includes activities and resources that capture formal curricular aspects directed towards all levels of teaching. The educational activities r elated to this projecthave been bene ted by the acquisition of two planetariums made in Argentina, a MEADE 1600 telescope to be operated by remote control from any school-room in San Luis, and a naked-eye observatory with more than 30 pre-telescopic instruments, and other didactic tools specially designed for the teaching of Astronomy. Furthermore, an Internet site to upload all the astronomical activities suggested that has been developed along with a number of didactic and general-interest publications.

  2. Simon Newcomb: America's Unofficial Astronomer Royal

    Science.gov (United States)

    Graham, John

    2007-10-01

    Bill Carter and Merri Sue Carter Mantazas; xiii + 213 pp.; ISBN 1-59113-803-5 2006; $26.95 This book introduced me to a commanding figure in American science from the late nineteenth century: Simon Newcomb. Newcomb has been called the nineteenth-century equivalent of Carl Sagan and Albert Einstein. He rose from humble beginnings to be the preeminent American astronomer of his generation. He made basic, far-reaching, and enduring contributions to positional astronomy and planetary dynamics. On the more practical side, he determined a remarkably accurate value for the velocity of light, one within 0.01% of the value accepted today. His work provided an experimental grounding for the special and general theories of relativity to be formulated by Einstein in the coming twentieth century.

  3. Astronomical research at the Hopkins PHOENIX Observatory

    Science.gov (United States)

    Hopkins, J. L.

    1985-09-01

    After trying astrophotography and radio astronomy it was decided that the best way to do meaningful astronomical research at a small private observatory was by doing photoelectric photometry. Having the observatory located in the back yard of a private residence affors the luxury of observing any time the sky conditions permit. Also modest equipment is all that is needed to do accurate UBV photometry of stars 8th magnitude and brighter. Since beginning in 1980 the Hopkins Phoenix Observatory has published papers on several RS CVn star systems, 31 Cygni, 22 Vul, 18 Tau Per, and has followed the 1982-1984 eclipse of Epsilon Aurigae from its start to the present with over 1000 UBV measurements. In addition the Hopkins Phoenix Observatory has developed several pieces of photometry equipment including the HPO PEPH-101 photometer head and photon counting electronics.

  4. Are supernovae recorded in indigenous astronomical traditions?

    Science.gov (United States)

    Hamacher, Duane W.

    2014-07-01

    Novae and supernovae are rare astronomical events that would have had an influence on the skywatching peoples who witnessed them. Although several bright novae/supernovae have been visible during recorded human history, there are many proposed but no confirmed accounts of supernovae in indigenous oral traditions or material culture. Criteria are established for confirming novae/supernovae in oral traditions and material culture, and claims from around the world are discussed to determine if they meet these criteria. Aboriginal Australian traditions are explored for possible descriptions of novae/supernovae. Although representations of supernovae may exist in Aboriginal traditions, there are currently no confirmed accounts of supernovae in Indigenous Australian oral or material traditions.

  5. Bonaparte and the astronomers of Brera Observatory

    CERN Document Server

    Antonello, E

    2014-01-01

    In Northern Italy, between 1796 and 1814, Napoleon Bonaparte formed a Republic, and then a Kingdom, controlled by France. Milan was the capital of the State, and the Brera Palace was the main cultural centre, as regards both the arts and the sciences. Bonaparte probably intended to strengthen this characteristic of Brera, aiming at increasing its Italian and European relevance. We will discuss in detail in which way he interacted with the astronomers of Brera Observatory, and in particular with Barnaba Oriani, that was considered the local main representative of the 'republique des lettres', that is, the world of literature, arts and sciences. We propose a possible reconstruction of the effects of those complicated historical events on the Italian astronomy and on its relations with the European one.

  6. Multinational History of Strasbourg Astronomical Observatory

    CERN Document Server

    Heck, André

    2005-01-01

    Strasbourg Astronomical Observatory is quite an interesting place for historians: several changes of nationality between France and Germany, high-profile scientists having been based there, big projects born or installed in its walls, and so on. Most of the documents circulating on the history of the Observatory and on related matters have however been so far poorly referenced, if at all. This made necessary the compilation of a volume such as this one, offering fully-documented historical facts and references on the first decades of the Observatory history, authored by both French and German specialists. The experts contributing to this book have done their best to write in a way understandable to readers not necessarily hyperspecialized in astronomy nor in the details of European history. After an introductory chapter by the Editor, contributions by Wolfschmidt and by Duerbeck respectively deal extensively with the German periods and review people and instrumentation, while another paper by Duerbeck is more...

  7. Young astronomer in Denmark 1946 to 1958

    CERN Document Server

    Høg, Erik

    2015-01-01

    This is a personal account of how I became an astronomer. Fascinated by the stars and planets in the dark sky over Lolland, an island 100 km south of Copenhagen, the interest in astronomy was growing. Encouraged by my teachers, I polished mirrors and built telescopes with generous help from the local blacksmith and I observed light curves of variable stars. Studies at the Copenhagen University from 1950 gradually led me deeper into astronomy, especially astrometry (the astronomy of positions), guided by professor Bengt Str\\"omgren and my mentor dr. phil. Peter Naur. I was lucky to take part in the buildup of the new observatory at Brorfelde during the first difficult years and the ideas I gathered there have contributed to the two astrometry satellites Hipparcos and Gaia launched by the European Space Agency (ESA) in respectively 1989 and 2013.

  8. Integral Programme of Basic Astronomic Literacy Development

    Science.gov (United States)

    Tignanelli, H.

    2009-05-01

    We discuss the development and optimization of an ongoing educational project involving the whole population of the province of San Luis, Argentina. The core of the project includes activities and resources that capture formal curricular aspects directed towards all levels of teaching. The educational activities related to this project have been benefited by the acquisition of two planetariums made in Argentina, a MEADE 16'' telescope to be operated by remote control from any school-room in San Luis, and a naked-eye observatory with more than 30 pre-telescopic instruments, and other didactic tools specially designed for the teaching of Astronomy. Furthermore, an Internet site to upload all the astronomical activities suggested that has been developed along with a number of didactic and general-interest publications.

  9. World's fastest and most sensitive astronomical camera

    Science.gov (United States)

    2009-06-01

    The next generation of instruments for ground-based telescopes took a leap forward with the development of a new ultra-fast camera that can take 1500 finely exposed images per second even when observing extremely faint objects. The first 240x240 pixel images with the world's fastest high precision faint light camera were obtained through a collaborative effort between ESO and three French laboratories from the French Centre National de la Recherche Scientifique/Institut National des Sciences de l'Univers (CNRS/INSU). Cameras such as this are key components of the next generation of adaptive optics instruments of Europe's ground-based astronomy flagship facility, the ESO Very Large Telescope (VLT). ESO PR Photo 22a/09 The CCD220 detector ESO PR Photo 22b/09 The OCam camera ESO PR Video 22a/09 OCam images "The performance of this breakthrough camera is without an equivalent anywhere in the world. The camera will enable great leaps forward in many areas of the study of the Universe," says Norbert Hubin, head of the Adaptive Optics department at ESO. OCam will be part of the second-generation VLT instrument SPHERE. To be installed in 2011, SPHERE will take images of giant exoplanets orbiting nearby stars. A fast camera such as this is needed as an essential component for the modern adaptive optics instruments used on the largest ground-based telescopes. Telescopes on the ground suffer from the blurring effect induced by atmospheric turbulence. This turbulence causes the stars to twinkle in a way that delights poets, but frustrates astronomers, since it blurs the finest details of the images. Adaptive optics techniques overcome this major drawback, so that ground-based telescopes can produce images that are as sharp as if taken from space. Adaptive optics is based on real-time corrections computed from images obtained by a special camera working at very high speeds. Nowadays, this means many hundreds of times each second. The new generation instruments require these

  10. Geographic Information Processings for Astronomical Site Survey

    Science.gov (United States)

    Wu, N.; Liu, Y.; Zhao, M. Y.

    2015-01-01

    The geographic information is of great importance for the site survey of ground-based telescopes. Especially, an effective utilization of the geographic information system (GIS) has been one of the most significant methods for the remote analysis of modern site survey. The astronomical site survey should give consideration to the following geographical conditions: a large relative fall, convenient traffic conditions, and far away from populated areas. Taking into account of the convenience of construction and maintenance of the observatories as well as the living conditions of the scientists-in-residence, the optimum candidate locations may meet the conditions to be at a altitude between 3000 m and 5000 m and within one-hour drive from villages/towns. In this paper, as an example, we take the regions of the Great Baicao mountain ridge at Dayao county in Yunnan province to research the role of the GIS for site survey task. The results indicate that the GIS can provide accurate and intuitive data for us to understand the three dimensional landforms, rivers, roads, villages, and the distributions of the electric power as well as to forecast the tendency of the population and city development around. According to the analysis based on the GIS, we find that the top of the Great Baicao mountain ridge is flat and droughty. There are few inhabitants to distribute around the place while the traffic conditions are convenient. Moreover, it is a natural conservation area protected by the local government, and no industry with pollution sources exists in this region. Its top is 1500 m higher than the nearby village 10 km away, and 1800 m higher than the town center 50 km away. The Great Baicao mountain ridge is definitely an isolated peak in the area of the Yi nationality of Yunnan. Therefore, the GIS data analysis is a very useful for the remote investigation stage for site survey, and the GIS is the indispensable source for modern astronomical site survey.

  11. The Virtual Astronomical Observatory: Re-engineering Access to Astronomical Data

    CERN Document Server

    Hanisch, R J; Lazio, T J W; Bunn, S Emery; Evans, J; McGlynn, T A; Plante, R

    2015-01-01

    The U.S. Virtual Astronomical Observatory was a software infrastructure and development project designed both to begin the establishment of an operational Virtual Observatory (VO) and to provide the U.S. coordination with the international VO effort. The concept of the VO is to provide the means by which an astronomer is able to discover, access, and process data seamlessly, regardless of its physical location. This paper describes the origins of the VAO, including the predecessor efforts within the U.S. National Virtual Observatory, and summarizes its main accomplishments. These accomplishments include the development of both scripting toolkits that allow scientists to incorporate VO data directly into their reduction and analysis environments and high-level science applications for data discovery, integration, analysis, and catalog cross-comparison. Working with the international community, and based on the experience from the software development, the VAO was a major contributor to international standards ...

  12. Using Modern Technologies to Capture and Share Indigenous Astronomical Knowledge

    OpenAIRE

    Nakata, N. M.; Hamacher, D. W.; Warren, J.; Byrne, A; Pagnucco, M.; Harley, R.; Venugopal, S.; Thorpe, K.; Neville, R.; Bolt, R.

    2014-01-01

    Indigenous Knowledge is important for Indigenous communities across the globe and for the advancement of our general scientific knowledge. In particular, Indigenous astronomical knowledge integrates many aspects of Indigenous Knowledge, including seasonal calendars, navigation, food economics, law, ceremony, and social structure. We aim to develop innovative ways of capturing, managing, and disseminating Indigenous astronomical knowledge for Indigenous communities and the general public for t...

  13. Astronomical Books and Charts in the Book of Bibliographie Coreenne

    Science.gov (United States)

    Lee, Ki-Won; Yang, Hong-Jin; Park, Myeong-Gu

    2008-06-01

    We investigate astronomical materials listed in the book of Bibliographie Coréenne written by Maurice Courant. He classified ancient Korean books into nine Divisions (?) and thirty six Classes (?), and published them as three volumes (ranging from 1894 to 1896) and one supplement (in 1901). In total, 3,821 books including astronomical ones are listed together with information on physical size, possessional place, bibliographical note, and so forth. Although this book is an essential one in the field of Korea bibliography and contains many astronomical materials such as Cheon-Mun-Ryu-Cho ????, Si-Heon-Seo ??????, and Cheon-Sang-Yeol-Cha-Bun-Ya-Ji-Do ????????, it has not been well known to the public nor to astronomical society. Of 3,821 catalogues, we found that about 50 Items (?) are related to astronomy or astrology, and verified that most ! of them are located in the Kyujanggak Royal Library ???. We also found an unknown astronomical chart, Hon-Cheon-Chong-Seong-Yeol-Cha-Bun-Ya-Ji-Do ??????????. Because those astronomical materials are not well known to international astronomical community and there have been few studies on the materials in Korea, we here introduce and review them, particularly with the astronomical viewpoint.

  14. Software Package for Preparing and Processing of an Astronomical Observation

    Science.gov (United States)

    Vaduvescu, Ovidiu; Birlan, Mirel

    This paper presents an astronomical software package which draws celestial charts. It was conceived taking into account the technical possibilities available for the Romanian astronomers and the actual trend of the observational astronomy. The software package, now to its third version, comes to decrease the time to prepare an observation and to perform accurate charts for searching and identification.

  15. The lamps of Atlantis: an astronomical detective story

    Science.gov (United States)

    Roy, Archie E.

    1986-11-01

    The origin of the stellar constellations familiar to western astronomers from ancient times is discussed using astronomical, literary, and archaeological evidence. The precession of the equinoxes, the zone of avoidance and the orientation of the constellations, and early Greek and Minoan astronomy are considered.

  16. The Double Didactic Astronomical Quadrant for the XIII International Astronomical Olympiad

    OpenAIRE

    Maris, Michele; Corte, Claudio; Boehm, Conrad; Iafrate, Giulia; Ramella, Massimo

    2010-01-01

    Here we present the development of a simplified version of double astronomical quadrant, designed for educational aims and realized on the occasion of the observational round of the XIII International Astronomy Olympiad, held in Trieste (Italy) October 13-21, 2008. (Italia: In questo contributo illustriamo il progetto di una versione semplificata di doppio quadrante astronomico, progettato per fini didattici e realizzato in occasione dello svolgimento della gara osservativa delle XIII Olimpia...

  17. The Victorian Amateur Astronomer: Independent Astronomical Research in Britain 1820-1920

    Science.gov (United States)

    Chapman, Allan

    1999-01-01

    This is the first book to look in detail at amateur astronomy in Victorian Britain. It deals with the technical issues that were active in Victorian astronomy, and reviews the problems of finance, patronage and the dissemination of scientific ideas. It also examines the relationship between the amateur and professional in Britain. It contains a wealth of previously unpublished biographical and anecdotal material, and an extended bibliography with notes incorporating much new scholarship. In The Victorian Amateur Astronomer, Allan Chapman shows that while on the continent astronomical research was lavishly supported by the state, in Britain such research was paid for out of the pockets of highly educated, wealthy gentlemen the so-called Grand Amateurs . It was these powerful individuals who commissioned the telescopes, built the observatories, ran the learned societies, and often stole discoveries from their state-employed colleagues abroad. In addition to the Grand Amateurs , Victorian Britain also contained many self-taught amateurs. Although they belonged to no learned societies, these people provide a barometer of the popularity of astronomy in that age. In the late 19th century, the comfortable middle classes clergymen, lawyers, physicians and retired military officers took to astronomy as a serious hobby. They formed societies which focused on observation, lectures and discussions, and it was through this medium that women first came to play a significant role in British astronomy. Readership: Undergraduate and postgraduate students studying the history of science or humanities, professional historians of science, engineering and technology, particularly those with an interest in astronomy, the development of astronomical ideas, scientific instrument makers, and amateur astronomers.

  18. Linking Young Astronomers in Southeast Asia: The SEAYAC Story

    Science.gov (United States)

    Dionisio Sese, Rogel Mari

    2015-08-01

    The importance of involving young astronomers in developing astronomy cannot be overemphasized. This is very much true in areas where astronomy is still an emerging and minor field, such as in the Southeast Asian (SEA) region. However, recent years have seen a sudden spark of interest in developing professional astronomy within SEA, primarily for young astronomers and students. This was especially highlighted during the 2009 International Year of Astronomy. In this presentation, we introduce the Southeast Asian Young Astronomers Collaboration (SEAYAC), a recently formed organization that aims to provide a venue for professional and personal interaction for young astronomers in the SEA region. Here we present the background and rationale behind the formation of SEAYAC, its current status as well as planned future activities aimed at developing collaborations between young astronomers in the SEA region. We will also discuss the problems and challenges being faced by SEAYAC as well as its future plan of actions.

  19. Combined Fluoroscopy- and CT-Guided Transthoracic Needle Biopsy Using a C-Arm Cone-Beam CT System: Comparison with Fluoroscopy-Guided Biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, Joo Yeon; Kim, Yoo Kyung; Shim, Sung Shine; Lim, Soo Mee [School of Medicine, Ewha Womans University, Seoul (Korea, Republic of)

    2011-02-15

    The aim of this study was to evaluate the usefulness of combined fluoroscopy- and CT-guided transthoracic needle biopsy (FC-TNB) using a cone beam CT system in comparison to fluoroscopy-guided TNB (F-TNB). We retrospectively evaluated 74 FC-TNB cases (group A) and 97 F-TNB cases (group B) to compare their respective diagnostic accuracies according to the size and depth of the lesion, as well as complications, procedure time, and radiation dose. The sensitivity for malignancy and diagnostic accuracy for small (< 30 mm in size) and deep ({>=} 50 mm in depth) lesions were higher in group A (91% and 94%, 92% and 94%) than in group B (73% and 81%, 84% and 88%), however not statistically significant (p > 0.05). Concerning lesions {>=} 30 mm in size and < 50 mm in depth, both groups displayed similar results (group A, 91% and 92%, 80% and 87%: group B, 90% and 92%, 86% and 90%). Pneumothorax occurred 26% of the time in group A and 14% for group B. The mean procedure time and patient skin dose were significantly higher in group A (13.6 {+-} 4.0 minutes, 157.1 {+-} 76.5 mGy) than in group B (9.0 {+-} 3.5 minutes, 21.9 {+-} 15.2 mGy) (p < 0.05). Combined fluoroscopy- and CT-guided TNB allows the biopsy of small (< 30 mm) and deep lesions ({>=} 50 mm) with high diagnostic accuracy and short procedure times, whereas F-TNB is still a useful method for large and superficial lesions with a low radiation dose

  20. C-arm cone-beam CT combined with a new electromagnetic navigation system for guidance of percutaneous needle biopsies. Initial clinical experience

    Energy Technology Data Exchange (ETDEWEB)

    Kickuth, R.; Reichling, C.; Bley, T.; Hahn, D.; Ritter, C. [University Hospital of Wuerzburg (Germany). Inst. of Diagnostic and Interventional Radiology

    2015-07-15

    To evaluate the feasibility and efficacy of C-arm fluoroscopic cone-beam computed tomography (CACT) in combination with a new electromagnetic tracking (EMT) system for needle guidance during percutaneous biopsies. 53 patients were referred for biopsy of thoracic (n = 19) and abdominal (n = 34) lesions. CT-like images of the anatomical region of interest (ROI) were generated using a flat panel-based angiographic system. These images were transmitted to an EMT system. A coaxial puncture needle with a sensor in its tip was connected with the navigation system and tracked into an electromagnetic field created via a field generator. Data generated within this field were merged with the CACT images. On a monitor both the anatomical ROI and needle tip position were displayed to enable precise needle insertion into the target. Through the coaxial needle, biopsy specimens for the histologic evaluation were extracted. Number of representative biopsy samples, number of core biopsies/patient, total procedure time, dose-area product, fluoroscopic time, and complications were recorded. 53 CACT/EMT-guided biopsy procedures were performed, 48 of which (91 %) yielded representative tissue samples. Four core biopsies were obtained from each patient. 40 (75 %) lesions were malignant and 13 (25 %) lesions were benign. The total procedure time was 9 ± 5 min (range, 3 - 23 min), fluoroscopic time was 0.8 ± 0.4 min (range, 0.4 - 2 min). The mean dose-area product (cGy cm{sup 2}) was 7373 (range, 895 - 26 904). The rate of complications (1 pneumothorax, 2 hemoptyses) was 6 %. CACT combined with EMT appears to be a feasible and effective technique for the guidance of percutaneous biopsies with a low rate of therapeutically relevant complications.

  1. Combination External Beam Radiation and Brachytherapy Boost With Androgen Suppression for Treatment of Intermediate-Risk Prostate Cancer: An Initial Report of CALGB 99809

    International Nuclear Information System (INIS)

    Purpose: Transperineal prostate brachytherapy (TPPB) can be used with external beam radiation therapy (EBRT) to provide a high-dose conformal boost to the prostate. The results of a multicenter Phase II trial assessing safety of combination of EBRT and TPPB boost with androgen suppression (AST) in treatment of intermediate-risk prostate cancer are present here. Materials and Methods: Patients had intermediate-risk prostate cancer. Six months of AST was administered. EBRT to the prostate and seminal vesicles was administered to 45Gy followed by TPPB using either 125I or 103Pd to deliver an additional 100Gy or 90Gy. Toxicity was graded using the National Cancer Institute CTC version 2 and the Radiation Therapy Oncology Group late radiation morbidity scoring systems. Results: Sixty-three patients were enrolled. Median follow-up was 38 months. Side effects of AST including sexual dysfunction and vasomotor symptoms were commonly observed. Apart from erectile dysfunction, short-term Grade 2 and 3 toxicity was noted in 21% and 7%, primarily genitourinary related. Long-term Grade 2 and 3 toxicities were noted in 13% and 3%. Two patients had Grade 3 dysuria that resolved with longer follow-up. The most common Grade 2 long-term toxicity was urinary frequency (5%). No biochemical or clinical evidence of progression was noted for the entire cohort. Conclusions: In a cooperative group setting, combination EBRT and TPPB boost with 6 months of AST was generally well tolerated with expected genitourinary and gastrointestinal toxicities. Further follow-up will be required to fully assess long-term toxicity and cancer control

  2. C-arm cone-beam CT combined with a new electromagnetic navigation system for guidance of percutaneous needle biopsies. Initial clinical experience

    International Nuclear Information System (INIS)

    To evaluate the feasibility and efficacy of C-arm fluoroscopic cone-beam computed tomography (CACT) in combination with a new electromagnetic tracking (EMT) system for needle guidance during percutaneous biopsies. 53 patients were referred for biopsy of thoracic (n = 19) and abdominal (n = 34) lesions. CT-like images of the anatomical region of interest (ROI) were generated using a flat panel-based angiographic system. These images were transmitted to an EMT system. A coaxial puncture needle with a sensor in its tip was connected with the navigation system and tracked into an electromagnetic field created via a field generator. Data generated within this field were merged with the CACT images. On a monitor both the anatomical ROI and needle tip position were displayed to enable precise needle insertion into the target. Through the coaxial needle, biopsy specimens for the histologic evaluation were extracted. Number of representative biopsy samples, number of core biopsies/patient, total procedure time, dose-area product, fluoroscopic time, and complications were recorded. 53 CACT/EMT-guided biopsy procedures were performed, 48 of which (91 %) yielded representative tissue samples. Four core biopsies were obtained from each patient. 40 (75 %) lesions were malignant and 13 (25 %) lesions were benign. The total procedure time was 9 ± 5 min (range, 3 - 23 min), fluoroscopic time was 0.8 ± 0.4 min (range, 0.4 - 2 min). The mean dose-area product (cGy cm2) was 7373 (range, 895 - 26 904). The rate of complications (1 pneumothorax, 2 hemoptyses) was 6 %. CACT combined with EMT appears to be a feasible and effective technique for the guidance of percutaneous biopsies with a low rate of therapeutically relevant complications.

  3. Planet Formation in Action? - Astronomers may have found the first object clearing its path in the natal disc surrounding a young star

    Science.gov (United States)

    2011-02-01

    gap in the dust disc around T Cha was a smoking gun, and we asked ourselves: could we be witnessing a companion digging a gap inside its protoplanetary disc?" However, finding a faint companion so close to a bright star is a huge challenge and the team had to use the VLT instrument NACO in a novel and powerful way, called sparse aperture masking, to reach their goal [4]. After careful analysis they found the clear signature of an object located within the gap in the dust disc, about one billion kilometres from the star - slightly further out than Jupiter is within our Solar System and close to the outer edge of the gap. This is the first detection of an object much smaller than a star within a gap in the planet-forming dust disc around a young star. The evidence suggests that the companion object cannot be a normal star [5] but it could be either a brown dwarf [6] surrounded by dust or, most excitingly, a recently formed planet. Huélamo concludes: "This is a remarkable joint study that combines two different state-of-the-art instruments at ESO's Paranal Observatory. Future observations will allow us to find out more about the companion and the disc, and also understand what fuels the inner dusty disc." Notes [1] The transitional discs can be spotted because they give off less radiation at mid-infrared wavelengths. The clearing of the dust close to the star and the creation of gaps and holes can explain this missing radiation. Recently formed planets may have created these gaps, although there are also other possibilities. [2] T Cha is a T Tauri star, a very young star that is still contracting towards the main sequence. [3] The astronomers used the AMBER instrument (Astronomical Multi-BEam combineR) and the VLTI to combine the light from all four of the 8.2-metre VLT Unit Telescopes and create a "virtual telescope" 130 metres across. [4] NACO (or NAOS-CONICA in full) is an adaptive optics instrument attached to ESO's Very Large Telescope. Thanks to adaptive optics

  4. Synergistic effect of combination of Irganox 1010 and zinc stearate on thermal stabilization of electron beam irradiated HDPE/EVA both in hot water and oven

    International Nuclear Information System (INIS)

    Thermo-oxidative stability of HDPE/EVA blends can be considerably increased by combination of a high-molecular weight phenolic antioxidant and zinc stearate. In this work, the post-irradiation thermal stability of HDPE/EVA blends has been studied. High-density polyethylene and its blends with ethylene-vinylacetate copolymer in both pure form and mixed with Irganox 1010 and zinc stearate were exposed to electron beam radiation at doses between 80 and 150 kGy, at room temperature, in air. In order to evaluate the thermal stability of the samples, post-irradiation heat treatments were done in both hot water bath at 95 deg. C and in an oven at 140 deg. C. The mechanical properties and changes in the chemical structure were determined during thermal aging in hot water and oven. The gel content was enhanced by increasing EVA concentration in all applied doses. The stabilized blends have lower gel content than the unstabilized samples. From the results of heat aging treatments it was observed that the thermal stability of the unstabilized blend samples was lower than HDPE. Thermal stability of the samples has been improved by incorporation of Irganox 1010 and zinc stearate. Formation of hydroxyl group was insignificant for stabilized samples during heat aging in both conditions. Also, the changes in the value of oxidation induction time (OIT) for the stabilized samples were negligible after prolonged immersion in hot water

  5. Database-Driven Analyses of Astronomical Spectra

    Science.gov (United States)

    Cami, Jan

    2012-03-01

    Spectroscopy is one of the most powerful tools to study the physical properties and chemical composition of very diverse astrophysical environments. In principle, each nuclide has a unique set of spectral features; thus, establishing the presence of a specific material at astronomical distances requires no more than finding a laboratory spectrum of the right material that perfectly matches the astronomical observations. Once the presence of a substance is established, a careful analysis of the observational characteristics (wavelengths or frequencies, intensities, and line profiles) allows one to determine many physical parameters of the environment in which the substance resides, such as temperature, density, velocity, and so on. Because of this great diagnostic potential, ground-based and space-borne astronomical observatories often include instruments to carry out spectroscopic analyses of various celestial objects and events. Of particular interest is molecular spectroscopy at infrared wavelengths. From the spectroscopic point of view, molecules differ from atoms in their ability to vibrate and rotate, and quantum physics inevitably causes those motions to be quantized. The energies required to excite vibrations or rotations are such that vibrational transitions generally occur at infrared wavelengths, whereas pure rotational transitions typically occur at sub-mm wavelengths. Molecular vibration and rotation are coupled though, and thus at infrared wavelengths, one commonly observes a multitude of ro-vibrational transitions (see Figure 13.1). At lower spectral resolution, all transitions blend into one broad ro-vibrational molecular band. The isotope. Molecular spectroscopy thus allows us to see a difference of one neutron in an atomic nucleus that is located at astronomical distances! Since the detection of the first interstellar molecules (the CH [21] and CN [14] radicals), more than 150 species have been detected in space, ranging in size from diatomic

  6. IYL Blog: Astronomers travel in time and space with light

    Science.gov (United States)

    Mather, John C.

    2015-01-01

    also using light to find out whether we are alone in the universe. The Kepler observatory showed that thousands of stars blink a little when their orbiting planets pass between us and them, and other observatories use light to measure the wobble of stars as their planets pull on them. Eventually, we will find out whether planets like Earth have atmospheres like Earth's too - with water, carbon dioxide, oxygen, methane, and other gases that would be evidence of photosynthetic life. I think in a few decades we will have evidence that some planets do have life, and it will be done using light for remote chemical analysis. Also, astronomers at the SETI project are using light (long wavelength light we can pick up with radio telescopes) to look for signals from intelligent civilizations. That's a harder project because we don't know what to look for. But if we wanted to send signals all the way across the Milky Way, we could do it with laser beams, and if somebody over there knew what to look for, he or she could decode the message. On with the search! Dr. John C. Mather is a Senior Astrophysicist and is the Senior Project Scientist for the James Webb Space Telescope at NASA's Goddard Space Flight Center in Greenbelt, MD. His research centers on infrared astronomy and cosmology. With the Cosmic Background Explorer (COBE) team, he showed that the cosmic microwave background radiation has a blackbody spectrum within 50 parts per million, confirming the expanding universe model (aka the Big Bang Theory) to extraordinary accuracy, and initiating the study of cosmology as a precision science. The COBE team also made the first map of the hot and cold spots in the background radiation. The COBE maps have been confirmed and improved by two succeeding space missions, the Wilkinson Microwave Anisotropy Probe (WMAP, built by GSFC with Princeton University), and the Planck mission built by ESA. Based on these maps, astronomers have now developed a "standard model" of cosmology and have

  7. High-School Student Discovers Strange Astronomical Object

    Science.gov (United States)

    2009-09-01

    of energy," he exclaimed. Rotating radio transients are thought to be similar to pulsars, superdense neutron stars that are the corpses of massive stars that exploded as supernovae. Pulsars are known for their lighthouse-like beams of radio waves that sweep through space as the neutron star rotates, creating a pulse as the beam sweeps by a radio telescope. While pulsars emit these radio waves continuously, rotating radio transients emit only sporadically, one burst at a time, with as much as several hours between bursts. Because of this, they are difficult to discover and observe, with the first one only discovered in 2006. "These objects are very interesting, both by themselves and for what they tell us about neutron stars and supernovae," McLaughlin said. "We don't know what makes them different from pulsars -- why they turn on and off. If we answer that question, it's likely to tell us something new about the environments of pulsars and how their radio waves are generated," she added. "They also tell us there are more neutron stars than we knew about before, and that means there are more supernova explosions. In fact, we now almost have more neutron stars than can be accounted for by the supernovae we can detect," McLaughlin explained. The PSC, led by NRAO Education Officer Sue Ann Heatherly and Project Director Rachel Rosen, includes training for teachers and student leaders, and provides parcels of data from the GBT to student teams. The project involves teachers and students in helping astronomers analyze data from 1500 hours of observing with the GBT. The 120 terabytes of data were produced by 70,000 individual pointings of the giant, 17-million-pound telescope. Some 300 hours of the observing data were reserved for analysis by student teams. The student teams use analysis software to reveal evidence of pulsars. Each portion of the data is analyzed by multiple teams. In addition to learning to use the analysis software, the student teams also must learn to

  8. NRAO Astronomer Wins Prestigious Guggenheim Fellowship

    Science.gov (United States)

    2010-04-01

    Dr. Dale Frail, an astronomer at the National Radio Astronomy Observatory (NRAO) in Socorro, New Mexico, has been awarded a prestigious Guggenheim Fellowship, according to the John Simon Guggenheim Memorial Foundation. The Guggenheim Foundation describes its fellowships as "mid-career" awards "intended for men and women who have already demonstrated exceptional capacity for productive scholarship or exceptional creative ability in the arts." Frail, 48, has worked at the NRAO for more than 20 years, first as a postdoctoral fellow, and then as a staff scientist. He received his bachelor's degree in physics from Acadia University in Nova Scotia, and his Ph.D in astronomy from the University of Toronto. Frail is best known for his landmark contributions to the understanding of gamma ray bursts, making critical measurements that provided key insights into the mechanisms of these superenergetic and once-mysterious explosions. He also has made important contributions to the understanding of other astronomical phenomena, including pulsars and their neighborhoods, supernova remnants, and magnetars. In 1992, he was the co-discoverer, with Alex Wolszczan, of the first planets outside our own solar system. "We congratulate Dale on this well-deserved honor that recognizes not only his past achievements but also his potential for exciting scientific work in the future," said Dr. Fred K.Y. Lo, NRAO Director. "We're very proud to see one of our scientists receive such a great honor," Lo added. Frail is one of 180 recipients of this year's Guggenheim Fellowships, chosen from some 3,000 applicants. The fellowships were established in 1925 and past recipients include photographer Ansel Adams, author Saul Bellow, former Secretary of State Henry Kissinger, and chemist Linus Pauling. 102 Guggenheim Fellows have subsequently won Nobel Prizes, and others have received Pulitzer Prizes and other honors. As a Guggenheim Fellow, Frail intends to intensify his research in the areas of pulsars

  9. Radio Astronomers Set New Standard for Accurate Cosmic Distance Measurement

    Science.gov (United States)

    1999-06-01

    A team of radio astronomers has used the National Science Foundation's Very Long Baseline Array (VLBA) to make the most accurate measurement ever made of the distance to a faraway galaxy. Their direct measurement calls into question the precision of distance determinations made by other techniques, including those announced last week by a team using the Hubble Space Telescope. The radio astronomers measured a distance of 23.5 million light-years to a galaxy called NGC 4258 in Ursa Major. "Ours is a direct measurement, using geometry, and is independent of all other methods of determining cosmic distances," said Jim Herrnstein, of the National Radio Astronomy Observatory (NRAO) in Socorro, NM. The team says their measurement is accurate to within less than a million light-years, or four percent. The galaxy is also known as Messier 106 and is visible with amateur telescopes. Herrnstein, along with James Moran and Lincoln Greenhill of the Harvard- Smithsonian Center for Astrophysics; Phillip Diamond, of the Merlin radio telescope facility at Jodrell Bank and the University of Manchester in England; Makato Inoue and Naomasa Nakai of Japan's Nobeyama Radio Observatory; Mikato Miyoshi of Japan's National Astronomical Observatory; Christian Henkel of Germany's Max Planck Institute for Radio Astronomy; and Adam Riess of the University of California at Berkeley, announced their findings at the American Astronomical Society's meeting in Chicago. "This is an incredible achievement to measure the distance to another galaxy with this precision," said Miller Goss, NRAO's Director of VLA/VLBA Operations. "This is the first time such a great distance has been measured this accurately. It took painstaking work on the part of the observing team, and it took a radio telescope the size of the Earth -- the VLBA -- to make it possible," Goss said. "Astronomers have sought to determine the Hubble Constant, the rate of expansion of the universe, for decades. This will in turn lead to an

  10. The Moon in Close-up A Next Generation Astronomer's Guide

    CERN Document Server

    Wilkinson, John

    2010-01-01

    Information collected by recent space probes sent to explore the Moon by the USA, the European Space Agency, Japan, China and India has changed our knowledge and understanding of the Moon, particularly its geology, since the Apollo missions. This book presents those findings in a way that will be welcomed by amateur astronomers, students, educators and anyone interested in the Moon. Enhanced by many colour photos, it combines newly acquired scientific understanding with detailed descriptions and labelled photographic maps of the lunar surface. Guided by observation methods explained in the book and 17 Study Areas presented and carefully explained in the last chapter, amateur astronomers can observe these features from Earth using telescopes and binoculars. Readers who consult the photographic maps will gain a better understanding about the Moon’s topography and geology. The book is rounded out by a helpful glossary.

  11. Book Review: Scientific Writing for Young Astronomers

    Science.gov (United States)

    Uyttenhove, Jos

    2011-12-01

    EDP Sciences, Les Ulis, France. Part 1 : 162 pp. € 35 ISBN 978-2-7598-0506-8 Part 2 : 298 pp. € 60 ISBN 978-2-7598-0639-3 The journal Astronomy & Astrophysics (A&A) and EDP Sciences decided in 2007 to organize a School on the various aspects of scientific writing and publishing. In 2008 and 2009 Scientific Writing for Young Astronomers (SWYA) Schools were held in Blankenberge (B) under the direction of Christiaan Sterken (FWO-VUB). These two books (EAS publication series, Vol. 49 and 50) reflect the outcome of these Schools. Part 1 contains a set of contributions that discuss various aspects of scientific publication; it includes A&A Editors' view of the peer review and publishing process. A very interesting short paper by S.R. Pottasch (Kapteyn Astronomical Institute, Groningen, and one of the two first Editors-in Chief of A&A) deals with the history of the creation of the journal Astronomy & Astrophysics. Two papers by J. Adams et al. (Observatoire de Paris) discuss language editing, including a detailed guide for any non-native user of the English language. In 2002 the Board of Directors decided that all articles in A&A must be written in clear and correct English. Part 2 consists of three very extensive and elaborated papers by Christiaan Sterken, supplying guidelines to PhD students and postdoctoral fellows to help them compose scientific papers for different forums (journals, proceedings, thesis, etc.). This part is of interest not only for young astronomers but it is very useful for scholars of all ages and disciplines. Paper I "The writing process" (60 pp.) copes with the preparation of manuscripts, with communicating with editors and referees and with avoiding common errors. Delicate problems on authorship, refereeing, revising multi-authored papers etc. are treated in 26 FAQ's. Paper II "Communication by graphics" (120 pp.) is entirely dedicated to the important topic of communication with images, graphs, diagrams, tables etc. Design types of graphs

  12. Is astronomical research appropriate for developing countries?

    Science.gov (United States)

    Snowden, Michael S.

    An unproductive 45-cm astronomical telescope, given by JICA (Japan) to Sri Lanka, raises general questions as to the reasons for unproductive pure science in developing countries. Before installation, site, maintenance, and scientific objectives were discussed. The facility was launched with a conference organised by the UN Office for Outer Space Affairs. Unfortunately, no research or significant education has resulted after four years. The annual operating cost is U.S. $5000 per year, including salary for a trainee, maintenance, and a modest promotional programme. Comparison with a similar installation in Auckland suggests lack of funding or technical competence do not explain the failure in Sri Lanka. The facility in New Zealand, on the roof of Auckland University's Physics Department, has a slightly smaller budget but has led to modest but useful research and teaching. Lack of financial backing and expertise are often blamed for weak science in developing countries, but examination shows most of these countries have adequately skilled people, and plenty of resources for religion and military. General lack of motivation for science appears to be the principal reason. This lack of interest and highly inefficient bureaucracies are common to scientifically unproductive countries. They mostly lack the cultural and philosophical base of the European Renaissance that motivate the pursuit of modern science, an activity that violates human preferences. There are excellent facilities (ESO, SAAO, Cerro Tololo, and GONG) in some of these same countries, when administered from the West.

  13. Model based systems engineering for astronomical projects

    Science.gov (United States)

    Karban, R.; Andolfato, L.; Bristow, P.; Chiozzi, G.; Esselborn, M.; Schilling, M.; Schmid, C.; Sommer, H.; Zamparelli, M.

    2014-08-01

    Model Based Systems Engineering (MBSE) is an emerging field of systems engineering for which the System Modeling Language (SysML) is a key enabler for descriptive, prescriptive and predictive models. This paper surveys some of the capabilities, expectations and peculiarities of tools-assisted MBSE experienced in real-life astronomical projects. The examples range in depth and scope across a wide spectrum of applications (for example documentation, requirements, analysis, trade studies) and purposes (addressing a particular development need, or accompanying a project throughout many - if not all - its lifecycle phases, fostering reuse and minimizing ambiguity). From the beginnings of the Active Phasing Experiment, through VLT instrumentation, VLTI infrastructure, Telescope Control System for the E-ELT, until Wavefront Control for the E-ELT, we show how stepwise refinements of tools, processes and methods have provided tangible benefits to customary system engineering activities like requirement flow-down, design trade studies, interfaces definition, and validation, by means of a variety of approaches (like Model Checking, Simulation, Model Transformation) and methodologies (like OOSEM, State Analysis)

  14. The Taiwan Extragalactic Astronomical Data Center

    CERN Document Server

    Foucaud, Sébastien; Tsai, Meng-Feng; Kamennoff, Nicolas

    2012-01-01

    Founded in 2010, the Taiwan Extragalactic Astronomical Data Center (TWEA-DC) has for goal to propose access to large amount of data for the Taiwanese and International community, focusing its efforts on Extragalactic science. In continuation with individual efforts in Taiwan over the past few years, this is the first steppingstone towards the building of a National Virtual Observatory. Taking advantage of our own fast indexing algorithm (BLINK), based on a octahedral meshing of the sky coupled with a very fast kd-tree and a clever parallelization amongst available resources, TWEA-DC will propose from spring 2013 a service of "on-the-fly" matching facility, between on-site and user-based catalogs. We will also offer access to public and private raw and reducible data available to the Taiwanese community. Finally, we are developing high-end on-line analysis tools, such as an automated photometric redshifts and SED fitting code (APz), and an automated groups and clusters finder (APFoF).

  15. The Blue Comet: A Railroad's Astronomical Heritage

    Science.gov (United States)

    Rumstay, Kenneth S.

    2009-01-01

    Between 1929 February 21 and 1941 September 27, the Central New Jersey Railroad operated a luxury passenger train between Jersey City and Atlantic City. Named The Blue Comet, the locomotive, tender, and coaches sported a unique royal blue paint scheme designed to evoke images of celestial bodies speeding through space. Inside each car were etched window panes and lampshades featuring stars and comets. And each coach sported the name of a famous comet on its side; these comets were of course named for their discoverers. Some of the astronomers honored in this unique fashion remain famous to this day, or at least their comets do. The names D'Arrest, Barnard, Encke, Faye, Giacobini, Halley, Olbers, Temple, Tuttle, and Westphal are familiar ones. But Biela, Brorsen, deVico, Spitaler, and Winnecke have now largely faded into obscurity; their stories are recounted here. Although more than sixty years have elapsed since its last run, The Blue Comet, perhaps the most famous passenger train in American history, lives on in the memories of millions of passengers and railfans. This famous train returned to the attention of millions of television viewers on the evening of 2007 June 3, in an episode of the HBO series The Sopranos. This work was supported by a faculty development grant from Valdosta State University.

  16. "Flexible Path” and Future Astronomical Missions

    Science.gov (United States)

    Lester, Daniel F.; Thronson, H.

    2010-01-01

    The Review of U.S. Human Space Flight Plans Committee, led by Norm Augustine, which was chartered by the White House to consider options for human space flight, has focused on a "flexible path” scenario for trips beyond LEO to carry out a range of tasks. This scenario has strong implications for possible servicing and deployment of future astronomical facilities, especially at Lagrange points, as well as visits to small bodies in the inner solar system. While the viability of that option as an priority agency goal will be under study by the Administration, NASA has been already directed by Congress to consider at least such servicing and deployment opportunities that could bear on it. The scientific and mission ramifications of such opportunities will be reviewed, along with the suitability of the conceptual space transportation architecture to carry it out, an architecture that could involves a lunar return program. Well studied astrodynamical considerations make both Earth-Sun L2 and Earth-Moon L1/L2 points of particular interest for such work. The relevance to this flexible path scenario to the NASA Decadal Planning Team (DPT) study will be reviewed. This study, completed in 2000, but largely eclipsed by the emphasis on lunar return, anticipated many of the challenges and opportunities and major technology investments now being considered.

  17. First Visiting Astronomers at VLT KUEYEN

    Science.gov (United States)

    2000-04-01

    A Deep Look into the Universal Hall of Mirrors Starting in the evening of April 1, 2000, Ghislain Golse and Francisco Castander from the Observatoire Midi-Pyrénées (Toulouse, France) [1] were the first "visiting astronomers" at Paranal to carry out science observations with the second 8.2-m VLT Unit Telescope, KUEYEN . Using the FORS2 multi-mode instrument as a spectrograph, they measured the distances to a number of very remote galaxies, located far out in space behind two clusters of galaxies. Such observations may help to determine the values of cosmological parameters that define the geometry and fate of the Universe. After two nights of observations, the astronomers came away from Paranal with a rich harvest of data and a good feeling. "We are delighted that the telescope performed so well. It is really impressive how far out one can reach with the VLT, compared to the `smaller' 4-meter telescopes with which we previously observed. It opens a new window towards the distant, early Universe. Now we are eager to start reducing and analysing these data!" , Francisco Castander said. Measuring the Geometry of the Universe with Multiple Images in Cluster Lenses The present programme is typical of the fundamental cosmological studies that are now being undertaken with the ESO Very Large Telescope (VLT). Clusters of galaxies are very massive objects. Their gravitational fields intensify ("magnify") and distort the images of galaxies behind them. The magnification factor for the faint background galaxy population seen within a few arcminutes of the centre of a massive cluster at intermediate distance (redshift z ~ 0.2 - 0.4, i.e., corresponding to a look-back time of approx. 2 - 4 billion years) is typically larger than 2, and occasionally much larger. The clusters thus function as gravitational lenses . They may be regarded as "natural telescopes" that help us to see fainter objects further out into space than would otherwise be possible with our own telescopes. In a

  18. Neutron beam imaging with micromegas detectors in combination with neutron time-of-flight at the (nTOF) facility at CERN

    International Nuclear Information System (INIS)

    A bulk micromegas detector with the anode segmented in 2 orthogonal directions and equipped with a neutron/charged particle converter is employed at the neutron time-of-flight (nTOF) facility at CERN to determine the incident neutron beam profile and beam interception factor as a function of the neutron energy determined by the time of flight. Discrepancies between experimental results and simulations in the values of the beam interception factor range up to 12 % and are to be ascribed to a defect in the mesh of the bulk. Nevertheless the detector proved to be really useful for checking the alignment of the neutron beam optics of the facility. Measurements with a new pixelized bulk detector for the determination of the beam interception factor are for seen before the end of 2012

  19. A ΔE-E semiconductor detector combined with CsI(Tl) crystal for monitoring the relative electrons flux generated in interaction of accelerated nuclei beam on thin targets

    International Nuclear Information System (INIS)

    Experimental data are presented, obtained with a ΔE-E semiconductor detector combined with a CsI(Tl) inorganic scintillator crystal. The interaction between a beam of accelerated nuclei and thin targets is analyzed. We show that, as a result of this interaction, the secondary particles, including δ-electrons, are generated. In the case of δ-electrons it is possible to study the beam characteristics and the nature of interaction processes, which is of great interest in high-energy interaction

  20. Staring/focusing lobster-eye hard x-ray imaging for non-astronomical objects

    Science.gov (United States)

    Gertsenshteyn, Michael; Jannson, Tomasz; Savant, Gajendra

    2005-08-01

    A new approach to hard X-ray imaging is proposed, based on staring optics consisting of a lobster-eye lens. This new Staring Imaging Lobster-Eye X-Ray approach is especially suited to X-ray lobster-eye imaging of non-astronomical objects at finite distances, because the staring optics replacing the standard scanning optics, result in an extremely efficient power budget, making possible not only the use of low-efficiency Compton backscattering but also operation with low-flux X-ray beams, increasing operator safety. The lobster-eye optics, consisting of square-cross-section microchannels, transmit an X-ray beam by total external reflection. This mode of operation has already been verified for viewing astronomical objects. Its major challenge is minimizing image defocusing by apodization. For this purpose, a new lens imaging equation is derived, and a new local optical axis concept is defined. Applications include medical imaging, cargo inspection, non-destructive testing, industrial and security safeguards, and surveillance.

  1. Patient-specific scatter correction in clinical cone beam computed tomography imaging made possible by the combination of Monte Carlo simulations and a ray tracing algorithm

    International Nuclear Information System (INIS)

    Purpose: Cone beam computed tomography (CBCT) image quality is limited by scattered photons. Monte Carlo (MC) simulations provide the ability of predicting the patient-specific scatter contamination in clinical CBCT imaging. Lengthy simulations prevent MC-based scatter correction from being fully implemented in a clinical setting. This study investigates the combination of using fast MC simulations to predict scatter distributions with a ray tracing algorithm to allow calibration between simulated and clinical CBCT images. Material and methods: An EGSnrc-based user code (egscbct), was used to perform MC simulations of an Elekta XVI CBCT imaging system. A 60keV x-ray source was used, and air kerma scored at the detector plane. Several variance reduction techniques (VRTs) were used to increase the scatter calculation efficiency. Three patient phantoms based on CT scans were simulated, namely a brain, a thorax and a pelvis scan. A ray tracing algorithm was used to calculate the detector signal due to primary photons. A total of 288 projections were simulated, one for each thread on the computer cluster used for the investigation. Results: Scatter distributions for the brain, thorax and pelvis scan were simulated within 2 % statistical uncertainty in two hours per scan. Within the same time, the ray tracing algorithm provided the primary signal for each of the projections. Thus, all the data needed for MC-based scatter correction in clinical CBCT imaging was obtained within two hours per patient, using a full simulation of the clinical CBCT geometry. Conclusions: This study shows that use of MC-based scatter corrections in CBCT imaging has a great potential to improve CBCT image quality. By use of powerful VRTs to predict scatter distributions and a ray tracing algorithm to calculate the primary signal, it is possible to obtain the necessary data for patient specific MC scatter correction within two hours per patient

  2. Combined Photoacoustic Ultrasound and Beam Deflection Signal Monitoring of Gold Nanoparticle Agglomerate Concentrations in Tissue Phantoms Using a Pulsed Nd:YAG Laser

    Science.gov (United States)

    Khosroshahi, Mohammad E.; Mandelis, Andreas

    2015-06-01

    The purpose of this paper is to show and discuss the effects of the gold nanoparticle (Au-NPs) concentration inside a tissue phantom using a combined system of photoacoustics (PA) and optical beam deflection and their applications particularly to photoacoustic imaging. It was found that the PA signal from aggregated Au nanoparticles is significantly enhanced. The stock concentration of 100 nm Au-NPs was particles/mL from which three samples with 30 %, 70 %, and 90 % concentration were prepared using polyvinyl chloride-plastisol. Each sample was then irradiated across a line scan using a 10 ns pulsed Q-switched Nd:YAG laser at a 1 Hz repetition rate and so that no physical ablation was observed. The corresponding photoacoustic pressure was found to approximately cover a range between 10 kPa and 51 kPa. This corresponds to approximately 130 pJ to 315 pJ of acoustic energy radiated by Au-NPs into the tissue. The maximal efficacy of the transformation of optical energy into thermal energy was . Time-resolved photoacoustic deflection was also used to monitor the laser-interaction process. The results clearly indicated that (i) the photoacoustic signal amplitude varies in a given sample as a result of the non-uniform concentration distribution of embedded Au-NPs; (ii) an increase of the concentration increased the signal amplitude linearly; and (iii) at higher nanoparticle concentrations, the probe deflection was found to increase due to a steeper thermoelastic gradient as a result of a higher absorption by particle agglomerates and particle size-dependent dispersions.

  3. The Virtual Astronomical Observatory: Re-engineering access to astronomical data

    Science.gov (United States)

    Hanisch, R. J.; Berriman, G. B.; Lazio, T. J. W.; Emery Bunn, S.; Evans, J.; McGlynn, T. A.; Plante, R.

    2015-06-01

    The US Virtual Astronomical Observatory was a software infrastructure and development project designed both to begin the establishment of an operational Virtual Observatory (VO) and to provide the US coordination with the international VO effort. The concept of the VO is to provide the means by which an astronomer is able to discover, access, and process data seamlessly, regardless of its physical location. This paper describes the origins of the VAO, including the predecessor efforts within the US National Virtual Observatory, and summarizes its main accomplishments. These accomplishments include the development of both scripting toolkits that allow scientists to incorporate VO data directly into their reduction and analysis environments and high-level science applications for data discovery, integration, analysis, and catalog cross-comparison. Working with the international community, and based on the experience from the software development, the VAO was a major contributor to international standards within the International Virtual Observatory Alliance. The VAO also demonstrated how an operational virtual observatory could be deployed, providing a robust operational environment in which VO services worldwide were routinely checked for aliveness and compliance with international standards. Finally, the VAO engaged in community outreach, developing a comprehensive web site with on-line tutorials, announcements, links to both US and internationally developed tools and services, and exhibits and hands-on training at annual meetings of the American Astronomical Society and through summer schools and community days. All digital products of the VAO Project, including software, documentation, and tutorials, are stored in a repository for community access. The enduring legacy of the VAO is an increasing expectation that new telescopes and facilities incorporate VO capabilities during the design of their data management systems.

  4. Detection and removal of artifacts in astronomical images

    Science.gov (United States)

    Desai, S.; Mohr, J. J.; Bertin, E.; Kümmel, M.; Wetzstein, M.

    2016-07-01

    Astronomical images from optical photometric surveys are typically contaminated with transient artifacts such as cosmic rays, satellite trails and scattered light. We have developed and tested an algorithm that removes these artifacts using a deep, artifact free, static sky coadd image built up through the median combination of point spread function (PSF) homogenized, overlapping single epoch images. Transient artifacts are detected and masked in each single epoch image through comparison with an artifact free, PSF-matched simulated image that is constructed using the PSF-corrected, model fitting catalog from the artifact free coadd image together with the position variable PSF model of the single epoch image. This approach works well not only for cleaning single epoch images with worse seeing than the PSF homogenized coadd, but also the traditionally much more challenging problem of cleaning single epoch images with better seeing. In addition to masking transient artifacts, we have developed an interpolation approach that uses the local PSF and performs well in removing artifacts whose widths are smaller than the PSF full width at half maximum, including cosmic rays, the peaks of saturated stars and bleed trails. We have tested this algorithm on Dark Energy Survey Science Verification data and present performance metrics. More generally, our algorithm can be applied to any survey which images the same part of the sky multiple times.

  5. POLYCOMP: Efficient and configurable compression of astronomical timelines

    Science.gov (United States)

    Tomasi, M.

    2016-07-01

    This paper describes the implementation of polycomp, a open-sourced, publicly available program for compressing one-dimensional data series in tabular format. The program is particularly suited for compressing smooth, noiseless streams of data like pointing information, as one of the algorithms it implements applies a combination of least squares polynomial fitting and discrete Chebyshev transforms that is able to achieve a compression ratio Cr up to ≈ 40 in the examples discussed in this work. This performance comes at the expense of a loss of information, whose upper bound is configured by the user. I show two areas in which the usage of polycomp is interesting. In the first example, I compress the ephemeris table of an astronomical object (Ganymede), obtaining Cr ≈ 20, with a compression error on the x , y , z coordinates smaller than 1 m. In the second example, I compress the publicly available timelines recorded by the Low Frequency Instrument (LFI), an array of microwave radiometers onboard the ESA Planck spacecraft. The compression reduces the needed storage from ∼ 6.5 TB to ≈ 0.75 TB (Cr ≈ 9), thus making them small enough to be kept in a portable hard drive.

  6. Polycomp: efficient and configurable compression of astronomical timelines

    CERN Document Server

    Tomasi, Maurizio

    2016-01-01

    This paper describes the implementation of polycomp, a open-sourced, publicly available program for compressing one-dimensional data series in tabular format. The program is particularly suited for compressing smooth, noiseless streams of data like pointing information, as one of the algorithms it implements applies a combination of least squares polynomial fitting and discrete Chebyshev transforms that is able to achieve a compression ratio Cr up to ~40 in the examples discussed in this work. This performance comes at the expense of a loss of information, whose upper bound is configured by the user. I show two areas in which the usage of polycomp is interesting. In the first example, I compress the ephemeris table of an astronomical object (Ganymede), obtaining Cr ~ 20, with a compression error on the x, y, z coordinates smaller than 1 m. In the second example, I compress the publicly available timelines recorded by the Low Frequency Instrument (LFI), an array of microwave radiometers onboard the ESA Planck ...

  7. The Double Didactic Astronomical Quadrant for the XIII International Astronomical Olympiad

    CERN Document Server

    Maris, Michele; Boehm, Conrad; Iafrate, Giulia; Ramella, Massimo

    2010-01-01

    Here we present the development of a simplified version of double astronomical quadrant, designed for educational aims and realized on the occasion of the observational round of the XIII International Astronomy Olympiad, held in Trieste (Italy) October 13-21, 2008. (Italia: In questo contributo illustriamo il progetto di una versione semplificata di doppio quadrante astronomico, progettato per fini didattici e realizzato in occasione dello svolgimento della gara osservativa delle XIII Olimpiadi Internazionali di Astronomia (XIII International Astronomy Olympiad, XIII IAO), Trieste (I), 13-21 ottobre 2008))

  8. Using XML and Java for Astronomical Instrument Control

    Science.gov (United States)

    Koons, L.; Ames, T.; Evans, R.; Warsaw, C.; Sall, K.

    1999-12-01

    Traditionally, instrument command and control systems have been highly specialized, consisting mostly of custom code that is difficult to develop, maintain, and extend. Such solutions are initially very costly and are inflexible to subsequent engineering change requests. Instrument description is too tightly coupled with details of implementation. NASA/Goddard Space Flight Center and AppNet, Inc. are developing a very general and highly extensible framework that applies to virtually any kind of instrument that can be controlled by a computer (e.g., telescopes, microscopes and printers). A key aspect of the object-oriented architecture, implemented in Java, involves software that is driven by an instrument description. The Astronomical Instrument Markup Language (AIML) is a domain-specific implementation of the more generalized Instrument Markup Language (IML). The software architecture combines the platform-independent processing capabilities of Java with the vendor-independent data description syntax of Extensible Markup Language (XML), a human-readable and machine-understandable way to describe structured data. IML is used to describe command sets (including parameters, datatypes, and constraints) and their associated formats, telemetry, and communication mechanisms. The software uses this description to present graphical user interfaces to control and monitor the instrument. Recent efforts have extended to command procedures (scripting) and representation of data pipeline inputs, outputs, and connections. Near future efforts are likely to include an XML description of data visualizations, as well as the potential use of XSL (Extensible Stylesheet Language) to permit astronomers to customize the user interface on several levels: per user, instrument, subsystem, or observatory-wide. Our initial prototyping effort was targeted for HAWC (High-resolution Airborne Wideband Camera), a first-light instrument of SOFIA (the Stratospheric Observatory for Infrared Astronomy

  9. Removal of SO2 and NO/sub x/ from flue gas by means of a spray dryer/electron beam combination: a feasibility study

    International Nuclear Information System (INIS)

    This study examines the feasibility of adding an electron beam between the spray dryer and the fabric filter of dry scrubber flue gas desulfurization (FGD) systems. The beam promises effective removal of nitrogen oxides (NO/sub x/) and sulfur dioxide (SO2), even at higher coal-sulfur levels than usually economic for dry scrubbers. The beam excites gas molecules, promoting reactions that convert SO2 and NO/sub x/ to acids that then react with calcium compounds and are removed by the filter. Concerns examined here are feasibility and waste disposal. The cost findings are promising for both manufacture and operation. The system uses commercially available components. The relatively low temperatures and high humidity downstream of the spray dryer favor economic beam operation. The beam removes SO2, so the dryer can be run for economy, not high removal. The beam's incidental heating effect reduces reheat cost. Safe landfilling of the nitrate-rich waste appears practical, with leachate carrying no more nitrate than natural rain and dustfall. We expect natural pozzolanic reactions between alumina-silica compounds in the fly ash and lime compounds from the spray dryer to form an impermeable concrete-like material within 10 days after landfilling. Dry scrubber with electron beam appears competitive with commercial FGD systems, and we recommend a pilot scale operation

  10. Lessons from the masters current concepts in astronomical image processing

    CERN Document Server

    2013-01-01

    There are currently thousands of amateur astronomers around the world engaged in astrophotography at increasingly sophisticated levels. Their ranks far outnumber professional astronomers doing the same and their contributions both technically and artistically are the dominant drivers of progress in the field today. This book is a unique collaboration of individuals, all world-renowned in their particular area, and covers in detail each of the major sub-disciplines of astrophotography. This approach offers the reader the greatest opportunity to learn the most current information and the latest techniques directly from the foremost innovators in the field today.   The book as a whole covers all types of astronomical image processing, including processing of eclipses and solar phenomena, extracting detail from deep-sky, planetary, and widefield images, and offers solutions to some of the most challenging and vexing problems in astronomical image processing. Recognized chapter authors include deep sky experts su...

  11. Relying on electronic journals: Reading patterns of astronomers

    Science.gov (United States)

    Tenopir, Carol; King, Donald W.; Boyce, Peter; Grayson, Matt; Paulson, Keri-Lynn

    2005-06-01

    Surveys of the members of the American Astronomical Society identify how astronomers use journals and what features and formats they prefer. While every work field is distinct, the patterns of use by astronomers may provide a glimpse of what to expect of journal patterns and use by other scientists. Astronomers, like other scientists, continue to invest a large amount of their time in reading articles and place a high level of importance on journal articles. They use a wide variety of formats and means to get access to materials that are essential to their work in teaching, service, and research. They select access means that are convenient - whether those means be print, electronic, or both. The availability of a mature electronic journals system from their primary professional society has surely influenced their early adoption of e-journals.

  12. Astronomical Software Wants To Be Free: A Manifesto

    CERN Document Server

    Weiner, Benjamin J; Coil, Alison L; Cooper, Michael C; Davé, Romeel; Hogg, David W; Holden, Bradford P; Jonsson, Patrik; Kassin, Susan A; Lotz, Jennifer M; Moustakas, John; Newman, Jeffrey A; Prochaska, J X; Teuben, Peter J; Tremonti, Christy A; Willmer, Christopher N A

    2009-01-01

    Astronomical software is now a fact of daily life for all hands-on members of our community. Purpose-built software for data reduction and modeling tasks becomes ever more critical as we handle larger amounts of data and simulations. However, the writing of astronomical software is unglamorous, the rewards are not always clear, and there are structural disincentives to releasing software publicly and to embedding it in the scientific literature, which can lead to significant duplication of effort and an incomplete scientific record. We identify some of these structural disincentives and suggest a variety of approaches to address them, with the goals of raising the quality of astronomical software, improving the lot of scientist-authors, and providing benefits to the entire community, analogous to the benefits provided by open access to large survey and simulation datasets. Our aim is to open a conversation on how to move forward. We advocate that: (1) the astronomical community consider software as an integra...

  13. The Educational Activities of the Astronomical Society of the Pacific.

    Science.gov (United States)

    Fraknoi, Andrew

    1981-01-01

    Describes educational activities of the Astronomical Society of the Pacific including learning packets on various astronomy concepts, Morrison lectures, newspaper columns, teacher workshops, cosponsoring astronomy oriented lectures, and providing speakers for various groups. (DS)

  14. Architecture and performance of astronomical adaptive optics systems

    Science.gov (United States)

    Bloemhof, E.

    2002-01-01

    In recent years the technological advances of adaptive optics have enabled a great deal of innovative science. In this lecture I review the system-level design of modern astronomical AO instruments, and discuss their current capabilities.

  15. PPARC: Grid technology helps astronomers keep pace with the Universe

    CERN Multimedia

    2003-01-01

    "Intelligent Agent" computer programs are roaming the Internet and watching the skies. These programs, using Grid computing technology, will help astronomers detect some of the most dramatic events in the universe, such as massive supernova explosions (1 page).

  16. The Persian-Toledan Astronomical Connection and the European Renaissance

    CERN Document Server

    Heydari-Malayeri, M

    2007-01-01

    This paper aims at presenting a brief overview of astronomical exchanges between the Eastern and Western parts of the Islamic world from the 8th to 14th century. These cultural interactions were in fact vaster involving Persian, Indian, Greek, and Chinese traditions. I will particularly focus on some interesting relations between the Persian astronomical heritage and the Andalusian (Spanish) achievements in that period. After a brief introduction dealing mainly with a couple of terminological remarks, I will present a glimpse of the historical context in which Muslim science developed. In Section 3, the origins of Muslim astronomy will be briefly examined. Section 4 will be concerned with Khwarizmi, the Persian astronomer/mathematician who wrote the first major astronomical work in the Muslim world. His influence on later Andalusian astronomy will be looked into in Section 5. Andalusian astronomy flourished in the 11th century, as will be studied in Section 6. Among its major achievements were the Toledan Tab...

  17. A Multilingual on-line Dictionary of Astronomical Concepts

    CERN Document Server

    Heydari-Malayeri, M

    2009-01-01

    On the occasion of the International Year of Astronomy (IYA2009), we present a new interactive dictionary of astronomy and astrophysics, which contains about 7000 entries. This interdisciplinary and multicultural work is intended for professional and amateur astronomers, university students in astrophysics, as well as terminologists and linguists. A new approach is pursued in the formation of a scientific dictionary, which aims to display additional dimensions of astronomical concepts. Although Virtual Observatories recognize the necessity of efforts to define basic astronomical concepts and establish their reciprocal relations, so far they have mainly been confined to archiving observational data. The present dictionary could be an incipient contribution to cover and inter-relate the whole astronomical lexicon beyond subfields.

  18. Combination of the H1 and ZEUS inclusive cross-section measurements at proton beam energies of 460 GeV and 575 GeV and tests of low Bjorken-x phenomenological models

    International Nuclear Information System (INIS)

    A combination is presented of the inclusive neutral current e±p scattering cross section data collected by the H1 and ZEUS collaborations during the last months of the HERA II operation period with proton beam energies Ep of 460 and 575 GeV. The kinematic range of the cross section data covers low absolute four-momentum transfers squared, 1.5 GeV2 ≤ Q2 ≤ 110 GeV2, small values of Bjorken-x, 2.8.10-5 ≤ x ≤ 1.5.10-2, and high inelasticity y ≤ 0.85. The combination algorithm is based on the method of least squares and takes into account correlations of the systematic uncertainties. The combined data are used in the QCD fits to extract the parton distribution functions. The phenomenological low-x dipole models are tested and parameters of the models are obtained. A good description of the data by the dipole model taking into account the evolution of the gluon distribution is observed. The longitudinal structure function FL is extracted from the combination of the currently used H1 and ZEUS reduced proton beam energy data with previously published H1 nominal proton beam energy data of 920 GeV. A precision of the obtained values of FL is improved at medium Q2 compared to the published results of the H1 collaboration.

  19. Combination of the H1 and ZEUS inclusive cross-section measurements at proton beam energies of 460 GeV and 575 GeV and tests of low Bjorken-x phenomenological models

    Energy Technology Data Exchange (ETDEWEB)

    Belov, Pavel

    2013-06-15

    A combination is presented of the inclusive neutral current e{sup {+-}}p scattering cross section data collected by the H1 and ZEUS collaborations during the last months of the HERA II operation period with proton beam energies E{sub p} of 460 and 575 GeV. The kinematic range of the cross section data covers low absolute four-momentum transfers squared, 1.5 GeV{sup 2} {<=} Q{sup 2} {<=} 110 GeV{sup 2}, small values of Bjorken-x, 2.8.10{sup -5} {<=} x {<=} 1.5.10{sup -2}, and high inelasticity y {<=} 0.85. The combination algorithm is based on the method of least squares and takes into account correlations of the systematic uncertainties. The combined data are used in the QCD fits to extract the parton distribution functions. The phenomenological low-x dipole models are tested and parameters of the models are obtained. A good description of the data by the dipole model taking into account the evolution of the gluon distribution is observed. The longitudinal structure function F{sub L} is extracted from the combination of the currently used H1 and ZEUS reduced proton beam energy data with previously published H1 nominal proton beam energy data of 920 GeV. A precision of the obtained values of F{sub L} is improved at medium Q{sup 2} compared to the published results of the H1 collaboration.

  20. Space charge dominated beams

    International Nuclear Information System (INIS)

    After an introductory section on the relationship between emittance and beam Coulomb energy we discuss the properties of space charge dominated beams in progressive steps: from uniformly charged bunched beams to non-uniformly charged beams to correlation effects between particles (simulation beams or 'crystalline' beams). A practical application can be found in the beam dynamics of a high-current injector. The concept of correlation energy is of practical interest in computer simulation of high-brilliance beams, where one deals with an artificially enhanced two-particle Coulomb energy, if many real particles are combined into one simulation super-particle. This can be a source of non-physical emittance growth. (orig./HSI)