Plasmaspheric electron content derived from GPS TEC and FORMOSAT-3/COSMIC measurements: Solar minimum condition

The plasmaspheric electron content (PEC) was estimated by comparison of GPS TEC observations and FORMOSAT-3/COSMIC radio occultation measurements at the extended solar minimum of cycle 23/24. Results are retrieved for different seasons (equinoxes and solstices) of the year 2009. COSMIC-derived electron density profiles were integrated up to the height of 700 km in order to retrieve estimates of ionospheric electron content (IEC). Global maps of monthly median values of COSMIC IEC were constructed by use of spherical harmonics expansion. The comparison between two independent measurements was performed by analysis of the global distribution of electron content estimates, as well as by selection specific points corresponded to mid-latitudes of Northern America, Europe, Asia and the Southern Hemisphere. The analysis found that both kinds of observations show rather similar diurnal behavior during all seasons, certainly with GPS TEC estimates larger than corresponded COSMIC IEC values. It was shown that during daytime both GPS TEC and COSMIC IEC values were generally lower at winter than in summer solstice practically over all specific points. The estimates of PEC (h > 700 km) were obtained as a difference between GPS TEC and COSMIC IEC values. Results of comparative study revealed that for mid-latitudinal points PEC estimates varied weakly with the time of a day and reached the value of several TECU for the condition of solar minimum. Percentage contribution of PEC to GPS TEC indicated the clear dependence from the time with maximal values (more than 50–60%) during night-time and lesser values (25–45%) during day-time.     

Concepts of Gas Turbine Engine Improvement Through the Use of Choked-Flow Turbines

The new conceptual design of simple gas turbine engines for different purposes is presented. A choked-flow low-pressure turbine is used that allows reducing the number of stages and gas temperature in the relative motion ahead of blades. Application of such turbines with uncooled blades to reduce the cost of power-limited engines is considered.     

Synthesis of electrode system and simulation of ion-marking sensor for aerodynamic angle and airspeed measurement

A functional scheme, primary informative signals, a method of electrode system structural parameters synthesis and evaluation of a systematic error of the ion-marking sensor for aerodynamic angle and airspeed measurement are the focus of this paper.     

Computer-aided tests in the quality control system of aircraft engines

The quality control system for an aircraft engine that is continuously developed in the life cycle stages is considered. Main quality indicators and their control methodology are analyzed. The computer-aided tests are substantiated as part of the quality control system and their generalized technological process structure and its construction methodology are proposed.     

A study of Z-crimp structural parameters impact on strength under transverse compression and longitudinal shear

Results of exerimental studies for composite Z-crimp core geometry impact on strength under transverse compression and longitudinal shear are presented. Recommendations are given concerning selection of core structural parameters to increase its strength for the specified types of loading at the same volumetric density. Mechanical properties of panels with different composite cores are compared.     

Lunar Exploration Neutron Detector for the NASA Lunar Reconnaissance Orbiter

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.     

An approximated method of calculating the cellular insert influence in the carrying capacity of the direct-flow labyrinth seal

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.     

Numerical modeling of large elastoplastic strains in terms of principal stretches. I. Kinematics of elastoplastic strains

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.     

On calculation of ideal thrust augmenter

In this paper, a simple technique for calculating the ideal ejector thrust augmenter of a jet engine is presented. It is based on the well-known method for averaging the parameters of a nonuniform gas flow with the entropy of the initial flow being unchanged. Making use of the technique presented, we compare the calculated data on the pressure ratio in the gas being ejected as well as the thrust boost coefficient with those obtained by the other authors. Also shown is the existence of the thrust boost maximum in the ideal and real thrust augmenters when the value of the ejection coefficient is approximately equal to 100.     

Numerical modeling of RadioAstron SRT temperature deformations

The results of modeling the thermal deformations of a space radio telescope’s reflecting surface are presented in the paper. Calculations were performed for the versions of the most unfavorable telescope illumination by the Sun.