Use of probability indices for assessment of gas turbine power station reliability under commercial operation conditions

Some assessments of probability indices of operational reliability of a two-unit gas turbine power station equipped with the NK-37ST engine are presented. Also considered is the reliability of separate units operation and their joint work taking into account the Markovian process. The probability single and composite indices are calculated depending on the operating and recovery time of units.     

Characterizing bedrock lithologies using Small Crater Rims and Ejecta Probing (SCREP)

This paper describes the rationale, methodology, and importance of focusing on the rim and proximal ejecta of small (<5 km in diameter), immature impact craters to explore an underlying crustal lithology. Small Crater Rim and Ejecta Probing (SCREP) describes a methodology and application program that extracts bedrock spectral and compositional information from a remote sensing image. Extracted data can yield the pristine lithologies of a planetary crust that would otherwise be obscured by the products of space weathering processes. SCREP was developed with lunar data, specifically Clementine multispectral image mosaics, therefore the technique is discussed in this context. However, its application to other airless solar system bodies is apparent. Knowledge of the pristine bedrock compositions of a planetary crust provides insight into geological surface processes, which can be used to refine models of planetary interiors and their evolution.     

Physics of Solar Prominences: I—Spectral Diagnostics and Non-LTE Modelling

This review paper outlines background information and covers recent advances made via the analysis of spectra and images of prominence plasma and the increased sophistication of non-LTE (i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the prominence plasma in both its cool core and the hotter prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the prominence plasma and to the determination of prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex non-LTE models become necessary. We thus present the basics of non-LTE radiative transfer theory and the associated multi-level radiative transfer problems. The main results of one- and two-dimensional models of the prominences and their fine-structures are presented. We then discuss the energy balance in various prominence models. Finally, we outline the outstanding observational and theoretical questions, and the directions for future progress in our understanding of solar prominences.     

Flight efficiency of a pulsejet

Problems of the pulsejet flight efficiency dependence on the system parameter periodicity type are considered.     

Exact analytical solutions of a nonlinear nonstationary inverse problem of heat conduction for a body with low heat conduction coefficient

The analytical solution of a nonlinear nonstationary inverse problem of heat conduction for a bodies with low heat conduction coefficients of one-dimensional geometry is presented. The solutions obtained make it possible to restore the boundary conditions rather exactly using the results of heat flux measurements.     

Variation of aircraft GTE turbine disks cyclic life depending on operational factors

Influence of the free air temperature during aircraft takeoff and engine operating time upon the cyclic life of an aircraft GTE turbine disk made from the heat-resistance deformable nickel-base alloy is analyzed and the variation of engine operating parameters in the process of service is taken into account.     

Analysis and parametric synthesis of the air ion counter measurement channel with impulse signal pickup from the aspiration chamber

The measurement channel of the air ion counter with impulse signal pickup from the aspiration chamber is considered. Peculiarities of its functional parts operation are analyzed and restrictions imposed on their parameters are stated. A technique is proposed and a set of equations that allows determining design parameters of the functional counter parts is presented.     

Fatigue life of a plate with an arbitrary-shaped concentrator under low-cycle plane loading

A technique and an algorithm for calculating fatigue life of a plate with a concentrator under complex loading in the low-cycle fatigue region are presented and the life of the plate with different shape concentrators is considered. The local stress strain state is investigated in the framework of plane loading using the finite element method with the aid of the MSC NASTRAN software and the life is evaluated with the use of an integral criterion of the concentrator contour loaded-up condition.     

Choice of optimal parameters of a gasodynamic temperature stratification process in the supersonic gas flow

The results of design analysis of the different factor influence on the gasodynamic temperature flow stratification efficiency in the Leont’ev tube are presented. It is justified that the temperature stratification efficiency can be increased at the expense of using longitudinal ribs on the heat exchange surface in the subsonic flow path, and the parameters determining the process can be optimized.     

Scaling Effects in the Impact Resistance of Flat and Cylindrical Samples from Composite Materials

The scaling factors in the problems of assessing the resistance to high-speed impact of plates and shells are analytically determined. Numerical experimentation shows the possibility of applying certain scaling factors in assessing the impact resistance of laminated plates and shells from materials with orthotropic properties.