522 research outputs found

    Viscoelastic evaluation of biological soft tissue in crush process at subsonic level for anti-bird strike technology of airplane

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    Miniaturization and lightening of airplane are advanced to improve its economic efficiency, and the safety technology of airplane design becomes difficult while the accident of bird-strike is increasing year by year. Then a system of shock impact test by using airsoft rifle is developed to evaluate the design technology of anti-bird strike structure of airplane. The viscoelastic characteristics of specimen is evaluated by analyzing stress response using the modified Hertz contact theory and the wave equation at the moment when simple ball bullet is shot to specimen by the airsoft rifle. In the results of experiment, the obvious relationship is observed subjectively between quasi-static and impact responses of specimen. The evaluated viscoelastic relationship is applied to simulate the impact test by using LSDYNA with fundamental viscoelastic constitutive equation and the material parameters derived from the impact test, and the well similar behavior has been simulated by the constitutive equation. By using the developed technology here, the phantom imitating real bird will be developed as standard specimen for an anti-bird strike test in future

    Measurement of high-energy cosmic-ray electrons with a Polar Patrol Balloon

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    One of the major purpose of recent cosmic-ray studies is to know the origin, acceleration mechanism and propagation properties inside the Galaxy. Along this line many efforts have been spent to observe a precise spectrum of the electron component of cosmic-rays. The main difficulty to study high-energy electrons is the detection of these electrons. The flux is much lower than the abundant proton component, and we need an observation of long duration and a detector with a high rejection power against the background protons. We propose to carry a newly developed scintillating-fiber detector on the Polar Patrol Balloon (PPB) and to expose it for 30 days. The goal of this observation is to determine a definite electron energy-spectrum ranging from 10 GeV to TeV region based on a high statistical accuracy with a long exposure by the PPB. In the result, we can expect to obtain direct evidence for the origin of high-energy electrons and a precise knowledge of their propagation in the Galaxy including solar modulation effects on the electron flux

    MIP calibration and the long-term stability of CALET onboard the International Space Station

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    In August 2015, the CALorimetric Electron Telescope (CALET) docked with the International Space Station (ISS). CALET will measure the cosmic ray electron spectrum over the energy range of 1 GeV to 20 TeV with a very high resolution of 2% above 100 GeV, based on a dedicated instrument incorporating an exceptionally thick 30 radiation-length calorimeter with both total absorption and imaging units (TASC and IMC). Each TASC readout channel must be carefully calibrated to obtain the degree of precision necessary to achieve the high energy resolution. This report describes the specific calibration methods, focusing on the calibration of the energy deposit of each channel to obtain an ADC unit to energy conversion factor using Minimum Ionizing Particles (MIP), known as "the MIP calibration." To fully calibrate each lead tungstate (PWO) log of the TASC, it is first necessary to correct the position dependent effects so as to equalize the response along its length. In addition, because both the PWO light yield and the APD gain will vary with temperature, it is also required to correct for this temperature dependence. Following these corrections for the position and temperature dependence, and also using events extracted using event selection based on likelihood analysis, it was possible to find the energy conversion factor. With the excellent agreement between the conversion factors obtained from proton and helium MIP data, the validity of the absolute calibration of the energy conversion factor was confirmed. In the end, this report describes the analysis of the long term stability of the MIP calibration, from which it was concluded that the time dependence of the MIP peak value was successfully removed

    Polar Patrol Balloon experiment in Antarctica during 2002-2003

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    The first scientific campaign of the Polar Patrol Balloon (PPB) experiment (1st-PPB) was performed at Syowa Station in Antarctica during 1990-1991 and 1992-1993. Based on the fruitful results of the 1st-PPB experiment, the next campaign (2nd-PPB) will be carried out in the austral summer of 2002-2003. This paper summarizes the 2nd-PPB experiment. Four balloons in total will be launched to make astrophysics observations (1 balloon) and upper atmosphere physics observations (3 balloons). The first payload will carry a very sophisticated instrument that will observe primary cosmic-ray electrons in the energy range of 10 GeV - 1 TeV. The payloads of the latter 3 flights are identical to each other. They will be launched in as rapid a succession as weather conditions permit to form a cluster of balloons during their flights. Such a "Balloon Cluster" is suitable for observing the temporal evolution and spatial distribution of various phenomena in the various magnetospheric and ionospheric regions and their boundaries that the balloons will traverse during their circumpolar trajectory. The expected flight duration of each balloon is 20 days. Observation data will be obtained mainly by a satellite communication system with a much higher temporal resolution than that used in the 1st-PPB experiment

    Performance of the Charge Injection Capability of Suzaku XIS

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    A charge injection technique is applied to the X-ray CCD camera, XIS (X-ray Imaging Spectrometer) onboard Suzaku. The charge transfer inefficiency (CTI) in each CCD column (vertical transfer channel) is measured by the injection of charge packets into a transfer channel and subsequent readout. This paper reports the performances of the charge injection capability based on the ground experiments using a radiation damaged device, and in-orbit measurements of the XIS. The ground experiments show that charges are stably injected with the dispersion of 91eV in FWHM in a specific column for the charges equivalent to the X-ray energy of 5.1keV. This dispersion width is significantly smaller than that of the X-ray events of 113eV (FWHM) at approximately the same energy. The amount of charge loss during transfer in a specific column, which is measured with the charge injection capability, is consistent with that measured with the calibration source. These results indicate that the charge injection technique can accurately measure column-dependent charge losses rather than the calibration sources. The column-to-column CTI correction to the calibration source spectra significantly reduces the line widths compared to those with a column-averaged CTI correction (from 193eV to 173eV in FWHM on an average at the time of one year after the launch). In addition, this method significantly reduces the low energy tail in the line profile of the calibration source spectrum.Comment: Paper contains 18 figures and 15 tables. Accepted for publication in PAS
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