The x-ray experiment on-board the “astron”

This paper describes the X-ray instrumentation, its capabilities and preliminary results which have been obtained for first two months operation.     

Space radiation quality factor investigations with “NAUSICAA”-device on board the “MIR” space station

The estimation of radiation quality factor in space flights is a serious problem of space dosimetry. The solution of this problem is based on LET-spectra measurements. The “NAUSICAA”-device installed on the “MIR” station has a detector with a large geometric factor, that gives the possibility of measuring LET-spectra with sufficient statistic in relatively short time interval and hence the corresponding Q. LET-spectra are accumulated through 24 hour periods and equivalent dose (H), absorbed dose (D), quality factor and flux (F) are measured every 10 minutes. The obtained data permit the estimate of the diurnal Q and Q in South Atlantic Anomaly. These values vary in the range of 1.4 – 2.2. The analysis of these values including their comparison with the calculated results is given in this paper.     

Mortality and morphological anomalies related to the passage of cosmic heavy ions through the smallest flowering aquatic plant Wolffia arrhiza

Radiobiological effects of single cosmic heavy ions on individual, actively metabolizing test organisms, plants of Wolffia arrhiza, have been explored in an experiment flown aboard the Russian Biosatellite 10. Mortality induced during space flight, population dynamics during subsequent cultivation, and morphological anomalies occurring in the plants of these cultures were investigated. Correlation of these effects with the passage of a heavy ion was achieved by inserting monolayers of plants in a stack of surrounding plastic nuclear track detectors (BIO-STACK). Enhanced initial mortality and delayed decline of induced anomalies have been significantly associated with the passage of single heavy ions, in particular if ions penetrated the budding region of the plants. The prolonged persistence of anomalies in filial generations as an indication of delayed genetic damage has been detected for the first time as the consequence of the hit by a single heavy ion. Regarding radiation protection of space crew during prolonged missions, especially outside the magnetosphere, this appears to be a significant finding.     

Ultrastructural and growth indices of Chlorella culture in multicomponent aquatic systems under space flight conditions.

Submicroscopic organization of Chlorella cells cultivated under space flight conditions in three-component aquatic system has been studied. Comparison of the experimental cells with that of the controls revealed certain rearrangements of cell organelles particularly, a reduction in the amount of reserve polysaccharides in chloroplasts, increase of cell vacuolization and mitochondrion volume, complication configuration of plasmalemma evaginations and invaginations, and also disturbances in the process of cytokinesis. More over an increase in the number of Chlorella cells infected by bacteria was shown in the experimental variant. No considerable differences were established in the growth characteristics of the experimental and control populations. A comparative cytological analysis revealed general regularities of organelles in Chlorella cells cultivated under space flight condition in the uni- and multicomponent systems.     

Marangoni boundary layers

This paper deals with the theory of Marangoni boundary layers developing near the free surface of a nonuniformly heated liquid.

In the Introduction the notion of a thermocapillary effect is considered, and the conditions, under which thermocapillary flow is dominant, are elucidated. The similarity criteria of the problems are revealed, and the effects resulting from melt convection are considered.

In the second section the mathematical aspects of the theory of Marangoni boundary layers are considered. The boundary layer effect on the form of a free surface is investigated, and some examples are presented.

In Section 3 a qualitative flow pattern in a Marangoni boundary layer is analyzed, similarities and differences in the problems of Prandtl and Marangoni boundary layer theory are discussed. The possibility of Marangoni boundary layer degeneration at the outer boundary, as well as the initiation of flow containing a counter-stream zone are emphasized.

The fourth section outlines the calculation scheme on the basis of boundary-layer theory for convective flows with directed crystallization and in the absence of mass forces. Some examples are presented.

In the fifth section some problems of the theory of Marangoni boundary layers that need further investigation are discussed.     

Digital Communication Systems in Impulsive Atmospheric Radio Noise

Analyses are presented of the performance of binary and M-ary coherent and noncoherent communication systems operating in the impulsive atmospheric radio noise environment. The receiver is usually a maximum likelihood detector for white Gaussian interference and therefore has the form of a parallel bank of matched filters followed by decision circuitry. By employing a Poisson or generalized Shot noise model for the impulsive noise with a suitable probability density function (pdf), closed-form expressions and bounds of error probabilities for M-ary noncoherent and coherent amplitude-shift keying (ASK), phase-shift keying (PSK), and frequency-shift keying (FSK) systems are obtained and the results discussed.     

基于状态的维修在飞机外场维修保障中的应用研究

主要介绍了国外状态维修的发展趋势,从状态维修概念、状态维修系统工作流程等方面进行了较为详细的介绍。在剖析试飞阶段飞机外场维修保障的现状及其不足的基础上,运用基于状态的维修分析技术,进行了飞机外场维修方案优化和维修间隔优化方法研究,并给出了应用实例,期望能推动基于状态的维修在飞机外场试飞维修保障中的推广和应用。     

Computational modeling of interference between helicopter main and tail rotors based on nonlinear blade vortex model

The Mi-2 helicopter was taken as an example for modeling the main and tail rotors operation with account for the interference at low speed sliding flight. Aerodynamic characteristics were calculated. The form of nonlinear vortical wake was obtained.     

Development of the design scheme of cooling for a nozzle vane of high pressure turbine of gas turbine engine

The design schemes of cooling for the nozzle blades of high-temperature gas turbines are considered. The results of the thermal and hydraulic tests for the cooling systems of the nozzle vanes are presented. The prospective cooling system of the nozzle vanes of low and high pressure turbines is developed and presented. The test results for the vane with proposed design are presented.