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981.
The fault-tolerant air data/inertial reference unit (ADIRU) described is a key part of a fault-tolerant air data/inertial reference system (ADIRS) designed to be the inertial and air data reference for the ARINC 651 Integrated Modular Avionics (IMA) distributed architecture. The ADIRU has been designed to meet the commercial aviation market demands for low life cycle cost and high integrity fault detection, fault isolation, and redundancy management. The ADIRU's internal redundant resources provide quad channel redundancy that is one level higher than conventional triple redundant systems, allowing it to provide deferred maintenance capability. Robust partitioning, simple serial internal interfaces, and simple voting planes ensure that internal redundant components are properly utilized to provide high integrity system outputs. This relieves systems using it from having to perform their own redundancy management of the air data and inertial outputs from multiple sources required by conventional systems 相似文献
982.
P. Ubertini A. Bazzano L. Boccaccini N.A. Dipper L. Iafrate C. LaPadula M. Mastropietro R. Patriarca V. Polcaro M.L. Urciuoli 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(1):105-108
A new design of position sensitive spectroscopic proportional counter is described, for use in a balloon borne hard x-ray telescope. Initial position and spectral resolution data from a one-dimensional laboratory prototype are reported. With this device, the final telescope will have an angular resolution of better than 10 minutes of arc. 相似文献
983.
R Tixador G Richoilley G Gasset H Planel N Moatti L Lapchine L Enjalbert J Raffin R Bost S N Zaloguev M P Bragina A F Moroz N G Antsiferova F M Kirilova 《Acta Astronautica》1985,12(2):131-134
Cytos 2 experiment, carried out during the French-Soviet manned flight (July 1982), has studied the antibiotics sensitivity of bacteria cultivated in vitro during the orbital flight. The results show an increase of the antibiotics resistance and a larger thickness of the cellular envelope for the inflight cells. The increase of antibiotics resistance can be related to a stimulating effect of space on the cell growth rate or to changes of the cellular envelope structure. 相似文献
984.
T.K. Yeoman H.C. Scoffield D.M. Wright L.J. Baddeley A.N. Vasilyev N.V. Semenova 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
A brief review is provided of recent progress in understanding the ionospheric Alfvén resonator (IAR) at high latitude. Firstly, naturally occurring resonances of the IAR as detected by pulsation magnetometers in the auroral zone at Sodankylä and in the polar cap at Barentsburg are considered. The characteristics of the IAR in the two regions are broadly similar, although the effects of solar illumination are less clear at the higher latitudes. Secondly we review recent attempts to stimulate the IAR through high-power radio frequency experiments both in the auroral zone at Tromsø with the European Incoherent SCATter (EISCAT) heater, and within the polar cap at Longyearbyen with the Space Plasma Exploration by Active Radar (SPEAR) facility. In the auroral zone at, Tromsø the stimulated IAR has been observed by ground-based magnetometers, and through electron acceleration observed on the FAST spacecraft. At SPEAR in the polar cap, the stimulated IAR has been investigated, with ground magnetometers, with the first results indicative of a positive detection. 相似文献
985.
B.F. Gordiets Yu.N. Kulikov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(9):113-117
The plausible mechanisms of cooling of the nightside Venus' thermosphere are analysed with the aid of the model of the atmospheric heat budget that incorporates, in addition to thermal conduction and IR radiation in the 15 μ band of CO2, heating and cooling due to global scale winds, eddy turbulence, and IR radiation in the rotational bands of H2O and CO, as well as the 63 μ line of atomic oxygen. The H2O mixing ratio and parameters of turbulence required for cooling of the thermosphere down to the observed low temperatures are evaluated. 相似文献
986.
S. Azouggagh-McBride L.A. Roe M.A. Franzen J.A. Buffington D.W.G. Sears 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
Laboratory impact tests have been performed on experimental versions of a proposed robotic sample collector for extraterrestrial samples. The collector consists of a retractable aluminum ring containing an impregnable silicone compound that is pressed into the surface of the body to be sampled. As part of a comprehensive program to evaluate this idea, we have performed tests to determine if the samples embedded in the collector medium can survive the impact forces experienced during direct reentry, such as that of the recent Genesis sample return mission. For the present study, samples of sand, rock, glass, and chalk were subjected to decelerations of 1440–2880 g using drop tests. We found that even the most fragile samples, chosen to be representative of a wide range of the types of materials found on the surface of asteroids that have currently been studied, can withstand impacts of the intensity experienced by a sample return capsule during direct reentry. 相似文献
987.
Douglas Lynch A.E. Gerard Genello B. Michael Wicks C. 《Aerospace and Electronic Systems Magazine, IEEE》2007,22(1):8-10
This program will develop an automated and unmanned ultra-wide band (UWB) perimeter surveillance sensor designed to provide detection and tracking of personnel and vehicles at the perimeter of critical areas such as military installations and other such facilities. This effort describes the work being done for the protection of high value assets using a compact system which incorporates two technologies to enhance the probability of detection in stressing environments 相似文献
988.
This article is devoted to the experimental works carried out in the R2Ch blow-down wind tunnel in the framework of the atmospheric re-entry PRE-X demonstrator program and to the fundamental studies performed on a hollow cylinder-flare relative to crucial problem of the transitional shock-wave/boundary-layer interaction.Shock-wave/boundary-layer interactions in hypersonic flows may have major consequences on thermal loads, especially if the shock is strong enough to induce separation. The heat-flux density levels in the interaction region strongly depend on the nature, laminar or turbulent of the boundary-layer. Special attention should be paid to transitional interactions, which are likely to exist at altitude where the Mach number is high and the density low.The wide Reynolds number range achievable in the R2Ch facility and reliable heat-flux measurements by infrared thermography have allowed to investigate the viscous interaction on the deflected flaps of the demonstrator model and to point out the laminar-to-turbulent boundary-layer natural and forced transition, in the light of the in-depth analysis of results obtained from the hollow cylinder-flare study. 相似文献
989.
Some experimental data on the process of impulsive ultrasonic machining are presented. Also given are the data on variations in the impulsive vibration frequency of a workpiece and a tool. 相似文献
990.
T Takakura E Goto M Tanaka 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1996,18(4-5):255-258
An axis clinostat was constructed to create micro and negative gravity also a rotated flat disk was constructed with different rotation rates to give increased gravity, by centrifugal force up to 48 g. Rice seeds were grown on agar in tubes at the constant air temperature of 20 degrees C under an average light condition of 110 micromol/m2/sec(PPF). Humidity was not controlled but was maintained above 90%. Since the tube containers were not large enough for long cultivation, shoot and root growth were observed every 12 hours until the sixth day from seeding. The lengths of shoots and roots for each individual plant were measured on the last day. The stem lengths were increased by microgravity but the root lengths were not. Under the negative gravity, negative orthogeotropism and under microgravity, diageotropism was observed. No significant effect of increased gravity was observed on shoot and root growth. 相似文献