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101.
Bozdağ Ebru Ruan Youyi Metthez Nathan Khan Amir Leng Kuangdai van Driel Martin Wieczorek Mark Rivoldini Attilio Larmat Carène S. Giardini Domenico Tromp Jeroen Lognonné Philippe Banerdt Bruce W. 《Space Science Reviews》2017,211(1-4):571-594
Space Science Reviews - We present global and regional synthetic seismograms computed for 1D and 3D Mars models based on the spectral-element method. For global simulations, we implemented a... 相似文献
102.
Recent experience with different methods of drag prediction 总被引:5,自引:0,他引:5
During the recent past the process of engineering design has changed entirely because of rapid developments in computational simulations. In aerodynamic design, computational fluid dynamics (CFD) methods are slowly superseding empirical methods and design engineers are spending more and more time applying CFD tools to analyze and predict the aerodynamic characteristics of vehicles. The purpose of this paper is to review recent experiences in CFD-based drag prediction with an emphasis on flow solutions governed by the Euler and Reynolds-averaged Navier–Stokes equations. For these types of flow solutions, various drag analysis methodologies are outlined and applied to determine the drag of components of as well as whole-body airplanes, helicopters, and ground-based vehicles at subsonic and transonic flow conditions. The review demonstrates that although significant progress has been made, CFD-based drag prediction still faces a number of hurdles that must be dealt with before it will become more widely accepted. 相似文献
103.
K. Molders M. Quinet J. Decat B. Secco E. Dulière S. Pieters T. van der Kooij S. Lutts D. Van Der Straeten 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
As part of the ESA-funded MELiSSA program, Ghent University and the Université catholique de Louvain investigated the suitability, growth and development of four potato cultivars in hydroponic culture under controlled conditions with the aim to incorporate such cultivation system in an Environmental Control and Life Support System (ECLSS). Potato plants can fulfill three major functions in an ECLSS in space missions: (a) fixation of CO2 and production of O2, (b) production of tubers for human nutrition and (c) production of clean water after condensation of the water vapor released from the plants by transpiration. Four cultivars (Annabelle, Bintje, Desiree and Innovator) were selected and grown hydroponically in nutrient film technique (NFT) gullies in a growth chamber under controlled conditions. The plant growth parameters, tuber harvest parameters and results of tuber nutritional analysis of the four cultivars were compared. The four potato cultivars grew well and all produced tubers. The growth period lasted 127 days for all cultivars except for Desiree which needed 145 days. Annabelle (1.45 kg/m2) and Bintje (1.355 kg/m2) were the best performing of the four cultivars. They also produced two times more tubers than Desiree and Innovator. Innovator produced the biggest tubers (20.95 g/tuber) and Desiree the smallest (7.67 g/tuber). The size of Annabelle and Bintje potatoes were intermediate. Bintje plants produced the highest total biomass in term of DW. The highest non-edible biomass was produced by Desiree, which showed both the highest shoot and root DW. The manual length and width measurements were also used to predict the total tuber mass. The energy values of the tubers remained in the range of the 2010 USDA and Souci-Fachmann-Kraut food composition databases. The amount of Ca determined was slightly reduced compared to the USDA value, but close to the Souci-Fachmann-Kraut value. The concentration of Cu, Zn and P were high compared to both databases. 相似文献
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B Schmeider P Démoulin G Aulanier J.M Malherbe L van Driel-Gesztelyi C.H Mandrini T Roudier N Nitta L.K Harra-Murnion 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1997,19(12):1871-1874
We present evidences that emergence of new flux in the lower atmosphere leads to magnetic reconnection of field lines. In a first phase the phenomenon is observed in the chromosphere by the formation of dark filaments (arch filament system) which are overlaid by bright loops visible in soft X-rays. Different types of event appear according to the magnetic field configuration and the amount of energy involved. 3-D modelling of the photospheric magnetic field provides a new tool for understanding reconnection in real configurations. The observed chromospheric and coronal loops are good diagnostics for the modelling. We document our statement by examples obtained during coordinated campaigns with the H Multichannel Subtractive Double Pass spectrographs-MSDP (Pic du Midi and Tenerife) and the Yohkoh instruments. 相似文献
106.
This paper considers a spinning rigid body and a particle with internal motion under axial thrust. This model is helpful for gaining insights into the nutation anomalies that occurred near the end of orbit injections performed by STAR-48 rocket motors. The stability of this system is investigated by means of linearized equations about a uniform spin reference state. In this model, a double root does not necessarily imply instability. The resulting stability condition defines a manifold in the parameter space. A detailed study of this manifold and the parameter space shows that the envelope of the constant solutions is in fact the stability boundary. Only part of the manifold defines a physical system and the range of frequency values that make the system unstable is restricted. Also it turns out that an increase of the spring stiffness, which restrains the internal motion, does not necessarily increase the stability margin. The application of the model is demonstrated using the orbit injection data of ESA's Ulysses satellite in 1990. 相似文献
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Changed political objectives, straitened economic circumstances and an altered balance of capability and expertise in space endeavours have together produced more discussion of the need for international cooperation than ever before, but the meaning of the term has subtly shifted. Insisting on US ‘leadership’ is self-defeating; what is instead firmly desired by the USA's potential partners is a balanced relationship in which each nation makes an identifiable contribution and takes the lead in at least one of a package of projects. If this is going to happen, there must be an international forum or framework in which projects can be discussed and agreed. This in turn requires initiative at governmental level. 相似文献