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851.
C. Zeitlin S. Guetersloh L. Heilbronn J. Miller A. Fukumura Y. Iwata T. Murakami L. Sihver 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
A critical need for NASA is the ability to accurately model the transport of heavy ions in the Galactic Cosmic Rays (GCR) through matter, including spacecraft walls, equipment racks, etc. Nuclear interactions are of great importance in the GCR transport problem, as they can cause fragmentation of the incoming ion into lighter ions. Since the radiation dose delivered by a particle is proportional to the square of (charge/velocity), fragmentation reduces the dose delivered by incident ions. The other mechanism by which dose can be reduced is ionization energy loss, which can lead to some particles stopping in the shielding. This is the conventional notion of shielding, but it is not applicable to human spaceflight since the particles in the GCR tend to be too energetic to be stopped in the relatively thin shielding that is possible within payload mass constraints. Our group has measured a large number of fragmentation cross sections, intended to be used as input to, or for validation of, NASA’s radiation transport models. A database containing over 200 charge-changing cross sections and over 2000 fragment production cross sections has been compiled. In this report, we examine in detail the contrast between fragment measurements at large acceptance and small acceptance. We use output from the PHITS Monte Carlo code to test our assumptions using as an example 40Ar data (and simulated data) at a beam energy of 650 MeV/nucleon. We also present preliminary analysis in which isotopic resolution was attained for beryllium fragments produced by beams of 10B and 11B. Future work on the experimental data set will focus on extracting and interpreting production cross sections for light fragments. 相似文献
852.
K. Gustafsson L. Sihver D. Mancusi T. Sato G. Reitz T. Berger 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
The radiation environment in space is very different from the one encountered on Earth. In addition to the sparsely ionizing radiation, there are particles of different Z with energies ranging from keV up to hundreds of GeV which can cause severe damage to both electronics and humans. It is therefore important to understand the interactions of these highly ionizing particles with different materials such as the hull of space vehicles, human organs and electronics. We have used the Particle and Heavy-Ion Transport code System (PHITS), which is a three-dimensional Monte Carlo code able to calculate interactions and transport of particles and heavy ions with energies up to 100 GeV/nucleon in most matter. PHITS is developed and maintained by a collaboration between RIST (Research Organization for Information Science & Technology), JAEA (Japan Atomic Energy Agency), KEK (High Energy Accelerator Research Organization), Japan and Chalmers University of Technology, Sweden. For the purpose of examining the applicability of PHITS to the shielding design we have simulated the ESA facility Matroshka (MTR) designed and lead by the German Aerospace Center (DLR). Preliminary results are presented and discussed in this paper. 相似文献
853.
Evan A. Thomas Mark M. Weislogel David M. Klaus 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
It is well recognized that water handling systems used in a spacecraft are prone to failure caused by biofouling and mineral scaling, which can clog mechanical systems and degrade the performance of capillary-based technologies. Long duration spaceflight applications, such as extended stays at a Lunar Outpost or during a Mars transit mission, will increasingly benefit from hardware that is generally more robust and operationally sustainable over time. 相似文献
854.
I. G. Mitrofanov A. Bartels Y. I. Bobrovnitsky W. Boynton G. Chin H. Enos L. Evans S. Floyd J. Garvin D. V. Golovin A. S. Grebennikov K. Harshman L. L. Kazakov J. Keller A. A. Konovalov A. S. Kozyrev A. R. Krylov M. L. Litvak A. V. Malakhov T. McClanahan G. M. Milikh M. I. Mokrousov S. Ponomareva R. Z. Sagdeev A. B. Sanin V. V. Shevchenko V. N. Shvetsov R. Starr G. N. Timoshenko T. M. Tomilina V. I. Tretyakov J. Trombka V. S. Troshin V. N. Uvarov A. B. Varennikov A. A. Vostrukhin 《Space Science Reviews》2010,150(1-4):183-207
The design of the Lunar Exploration Neutron Detector (LEND) experiment is presented, which was optimized to address several of the primary measurement requirements of NASA’s Lunar Reconnaissance Orbiter (LRO): high spatial resolution hydrogen mapping of the Moon’s upper-most surface, identification of putative deposits of appreciable near-surface water ice in the Moon’s polar cold traps, and characterization of the human-relevant space radiation environment in lunar orbit. A comprehensive program of LEND instrument physical calibrations is discussed and the baseline scenario of LEND observations from the primary LRO lunar orbit is presented. LEND data products will be useful for determining the next stages of the emerging global lunar exploration program, and they will facilitate the study of the physics of hydrogen implantation and diffusion in the regolith, test the presence of water ice deposits in lunar cold polar traps, and investigate the role of neutrons within the radiation environment of the shallow lunar surface. 相似文献
855.
A pulsating flow of the incompressible viscoelastic fluid enclosed in the multilayer viscoelastic tube of a variable circular section is investigated. The problem stated leads to the singular Sturm-Liouville boundary value problem which in its turn is reduced to the equivalent integral equation of the Volterra type that is solved by the successive approximation method. The influence of fluid relaxation and retardation time on the wave system characteristics is revealed. 相似文献
856.
A. P. Paramonov 《Russian Aeronautics (Iz VUZ)》2010,53(2):121-125
Problems of improving the efficiency of design works in the process of space-rocket complex (SRC) updating are considered.
The methodical foundation for the expert system application to form promising technical solutions in studying the flight vehicle
(FV) modification is presented. 相似文献
857.
Basic principles of a mathematical model for disk-wing aircraft balancing and evaluation of power expenditure for flight as
compared with a helicopter are presented. 相似文献
858.
Methodology of constructing a stationary multichannel flow aerometric receiver using the effects of deceleration and throttling
of an incoming airflow and their circular transformation in the yaw plane is considered. The mathematical models and algorithms
for processing primary informative signals entering along the channels of speed, altitude, angles of attack and slip of the
helicopter air data system constructed on the basis of the aerometric receiver being proposed are obtained. 相似文献
859.
E. N. Bogomolov S. M. Piotukh I. A. Simonov V. A. Uglov 《Russian Aeronautics (Iz VUZ)》2010,53(4):416-420
A method for calculating the flowrate of the gas flowing through the cellular insert cells over the labyrinth seal strip is
proposed. The gas density is taken to be average with respect to the decisive section. It is assumed that jets flowing out
of cells disrupt the direct flow of the labyrinth seal. A practical implementation of the method is confirmed by the known
experimental data. 相似文献
860.
A. I. Golovanov 《Russian Aeronautics (Iz VUZ)》2010,53(2):161-166
A technique for numerical finite element analysis of large elastoplastic strains is proposed. A problem is formulated in terms
of principal stretches and their logarithms in the current basis of the left distortion tensor. It is shown that the “classical”
multiplicative decomposition of the total strain gradient into the product of elastic and plastic strain gradients is equivalent
to the presentation of total stretches as a product of elastic and plastic stretches. 相似文献