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Now showing items 1 - 16 of 52

  • Shot Peening Method for Aerofoil Treatment of Blisk Assemblies

    Wolfgang Hennig   Goetz Feldmann   Thomas Haubold  

    Abstract Advanced compressor designs today often include blade integrated disc (blisk) rotors, with high demands on aerodynamic performance, resistance againsthigh load levels and foreign object damage (FOD).To increasethe highcycle fatigue (HCF) strength, compressive residual stresses are introduced into the surface and subsurface layer of aerofoil, fillet (transient area between aerofoil and disk) and annulus (intermediate area between aerofoils). For generatingcompressive residual stresses several different industrial production processes are used, beside ultrasonic shot peening, laser shock peening, deep rolling and shot peening wet and dry with glass or ceramic media is shot peening with steel media the mostly used technology. However, depending on the size of the componentaccessibility for tools might be limited and the set-up of economical production techniques challenging for blisk shot peening. This paper gives an introduction into blisk shot peening, a sophisticated mechanical surface technology for treating aerofoil surfaces of blisk rotors using special designed calliper nozzles assolution for introducing uniform residual compressive stress states, as well as consistentshot peening coverage levels.
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  • Method and apparatus for surface strengthening of blisk blades

    For surface strengthening of blisk blades, a blade area of the blisk is completely inserted into a water bath (13), and a multitude of high-pressure water jets are injected into the water bath which are directed bilaterally and essentially vertically—and opposite to each other—to both blade sides. Cavitation bubbles imploding near the blade surface that are generated in the water bath on the periphery of the high-pressure water jets to produce micro jets upon imploding, exerting an effect on the blade surface, creating plastically formed depressions without sharp edges. An apparatus for performing the method includes a container (3), a jetting unit (6) having parallel spaced apart water-jet tubes (4) with nozzle openings connected to a high-pressure water conduit (5) to produce the high-pressure water jets.
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  • Study of silicon detectors for high resolution radioxenon measurements

    Wolfgang Hennig   Christopher E. Cox…  

    Measurement of radioactive xenon in the atmosphere is one of several techniques to detect nuclear weapons testing, typically using either scintillator based coincidence beta/gamma detectors or germanium based gamma only detectors. Silicon detectors have a number of potential advantages over these detectors (high resolution, low background, sensitive to photons and electrons) and are explored in this work as a possible alternative. Using energy resolutions from measurements and detection efficiencies from simulations of characteristic electron and photon energies, the minimum detectable concentration for Xe isotopes was estimated for several possible detector geometries. Test coincidence spectra were acquired with a prototype detector.
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  • Method for determining a machining result during surface machining of components

    A method for determining a machining result during surface machining of components, has the following method steps of: providing a component, applying at least one device, which changes under pressure, to the component, machining the surface of the component provided with the at least one device, evaluating the machining operation on the basis of the change in the at least one device as a result of the surface machining of the component. At least one device is in the form of a film which changes at least one property during the surface machining of the component.
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  • Histone modifications in the male germ line ofDrosophilaa

    Wolfgang Hennig   Alexandra Weyrich  

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  • Beam head

    The present embodiments relate to a beam head including a vacuum housing, in which an electron source is arranged. The beam head also includes a beam finger that is connected to the vacuum housing and has an outlet window at a distal end. The beam head includes a transformer housing, in which a transformer connected to the electron source is arranged. The transformer housing is arranged directly on the vacuum housing.
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  • A phoswich well detector for radioxenon monitoring

    Wolfgang Hennig   Hui Tan   Anthony Fallu-Labruyere   William K. Warburton   Justin I. McIntyre   Anshel Gleyzer  

    One of several methods used to detect nuclear weapons testing is the monitoring of radioactive xenon in the atmosphere. For high sensitivity, monitoring stations use a complex system of separate beta and gamma detectors to detect beta–gamma coincidences from characteristic radioxenon isotopes in small amounts of xenon extracted from large volumes of air.We report a simpler approach that uses a single phoswich detector, comprising optically coupled plastic and CsI scintillators to absorb beta particles and gamma rays, respectively, and then detect coincidences by pulse shape analysis of the detector signal. Previous studies with a planar prototype detector have shown that the technique can clearly separate beta only, gamma only and coincidence events, does not degrade the energy resolution, and has an error rate for detecting coincidences of less than 0.1%. In this paper, we will present a new phoswich well detector design, consisting of a 1′′ diameter plastic cell enclosed in a 3′′ CsI crystal. Based on Monte Carlo modeling and experimental results, the design will be characterized in terms of energy resolution and its ability to separate beta and gamma only, and coincidence events.
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  • A phoswich well detector for radioxenon monitoring

    Wolfgang Hennig   Hui Tan   Anthony Fallu-Labruyere   William K. Warburton   Justin I. McIntyre    Anshel Gleyzer  

    One of several methods used to detect nuclear weapons testing is the monitoring of radioactive xenon in the atmosphere. For high sensitivity, monitoring stations use a complex system of separate beta and gamma detectors to detect beta–gamma coincidences from characteristic radioxenon isotopes in small amounts of xenon extracted from large volumes of air.We report a simpler approach that uses a single phoswich detector, comprising optically coupled plastic and CsI scintillators to absorb beta particles and gamma rays, respectively, and then detect coincidences by pulse shape analysis of the detector signal. Previous studies with a planar prototype detector have shown that the technique can clearly separate beta only, gamma only and coincidence events, does not degrade the energy resolution, and has an error rate for detecting coincidences of less than 0.1%. In this paper, we will present a new phoswich well detector design, consisting of a 1′′ diameter plastic cell enclosed in a 3′′ CsI crystal. Based on Monte Carlo modeling and experimental results, the design will be characterized in terms of energy resolution and its ability to separate beta and gamma only, and coincidence events.
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  • Detection of coincident radiations in a single transducer by pulse shape analysis

    Pulse shape analysis determines if two radiations are in coincidence. A transducer is provided that, when it absorbs the first radiation produces an output pulse that is characterized by a shorter time constant and whose area is nominally proportional to the energy of the absorbed first radiation and, when it absorbs the second radiation produces an output pulse that is characterized by a longer time constant and whose area is nominally proportional to the energy of the absorbed second radiation. When radiation is absorbed, the output pulse is detected and two integrals are formed, the first over a time period representative of the first time constant and the second over a time period representative of the second time constant. The values of the two integrals are examined to determine whether the first radiation, the second radiation, or both were absorbed in the transducer, the latter condition defining a coincident event.
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  • Apparatus and method for shot peening of blade mounting areas on a rotor arrangement disc

    An apparatus for shot peening blade mounting areas on a disc of a rotor includes a peening nozzle unit which streams shot peening media along a longitudinal axis. The unit includes a nozzle outlet which extends at least partially in a circumferential direction of the unit, and a deflection arrangement with a deflection area for the media. The deflection area is at least partially cone or half-hyperboloid shaped, such that the media passes the nozzle outlet over an angle range in circumferential direction after being deflected by the deflection arrangement. A method for shot peening the blade mounting areas positions the unit in a slot profile of a blade mounting area, and guides the unit along the contour of the slot profile with the nozzle outlet facing the contour of the slot profile to approximately uniformly peen the contour of the slot profile.
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  • Method for the continuous casting of thin metal strip and continuous casting installation

    A method for the continuous casting of thin metal strip in a continuous casting installation, in which metal is discharged vertically downward from a mold, the metal strip is deflected from the vertical direction to the horizontal direction, and the metal strip is supported and/or conveyed and/or plastically deformed by a number of pairs of drive rolls. At least one pair of drive rolls plastically deforms the metal strip without significantly changing the mean thickness of the metal strip, namely with a change in the mean thickness of the metal strip of less than 5%, such that the deformation in the pairs of drive rolls produces material flow exclusively in the direction transverse to the direction of conveyance of the metal strip.
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  • Chromosomal proteins in the spermatogenesis ofDrosophila

    Wolfgang Hennig  

    Chromatin constitution in the male germ line of Drosophila is discussed with respect to the substitution of somatic histones by protamines or other basic proteins. The specific properties of germ line chromatin include the initiation and completion of the spermatogenic pathway and the reprogramming of the genome for embryonic development. During meiotic prophase cell cycle-regulated H3 histones appear to a large extent to be substituted by the histone H3.3 replacement variant protein, which is generally found associated with transcriptionally active chromatin. Condensation of the chromosomes during meiosis and the subsequent compaction for packaging in the sperm head require suitable proteins, but the cell cycle-regulated histones are not available as their expression is limited to S-phase. It is, therefore, proposed that any basic protein with a limited range of sequence requirements may take over this packaging function. Suitable proteins may have evolved by divergence from histone variants not restricted in their expression to S-phase, similar to the testes-predominant histone H3.3A of Drosophila.
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  • Chromosomal proteins in the spermatogenesis of Drosophila

    Wolfgang Hennig  

    Chromatin constitution in the male germ line of Drosophila is discussed with respect to the substitution of somatic histones by protamines or other basic proteins. The specific properties of germ line chromatin include the initiation and completion of the spermatogenic pathway and the reprogramming of the genome for embryonic development. During meiotic prophase cell cycle-regulated H3 histones appear to a large extent to be substituted by the histone H3.3 replacement variant protein, which is generally found associated with transcriptionally active chromatin. Condensation of the chromosomes during meiosis and the subsequent compaction for packaging in the sperm head require suitable proteins, but the cell cycle-regulated histones are not available as their expression is limited to S-phase. It is, therefore, proposed that any basic protein with a limited range of sequence requirements may take over this packaging function. Suitable proteins may have evolved by divergence from histone variants not restricted in their expression to S-phase, similar to the testes-predominant histone H3.3A of Drosophila.
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  • Sperm nuclear proteins

    Wolfgang Hennig   Juan Ausió  

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  • In memoriam: Wolfgang Beermann

    Wolfgang Hennig  

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  • In memoriam: Wolfgang Beermann

    Wolfgang Hennig  

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