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We study the process of wear of the fifth wheel of an articulated road train in order to determine its residual life. For this unit, we obtain the energy criterion of wear with an aim to determine the parameters affecting its service life.

The paper presents an approximate algorithm for modeling a stationary discrete random process with marginal and bivariate distributions of its consecutive components in the form of a mixture of two Gaussian distributions. The algorithm is based on a combination of the conditional distribution method and the rejection method. An example of application of the proposed algorithm for simulating time series of daily maximum air temperatures is given.

A new iterative method for modeling of non-Gaussian random vectors with given marginal distributions and a covariance matrix is proposed in this paper. The algorithm is compared with another iterative algorithm for modeling of non-Gaussian vectors, based on reordering of a sample of independent random variables with given marginal distributions. Our numerical studies show that both algorithms are equivalent in terms of the accuracy of reproduction of a given covariance matrix, but the offered algorithm turns out to be more efficient in terms of memory usage and, in many cases, is faster than the other one.

Aspects of implementing the homophasic free-radical synthesis in DMSO of a fiber-forming tercopolymer (FTP) based on acrylonitrile, methacrylate, and 2-acrylamide-2-methylpropanesulfonic acid with a given intrinsic viscosity are considered. The macrokinetic process parameters, yield, and intrinsic viscosity of the FTP as a function of the initiator content in the reaction solution are established. General and distinguishing features of the FTP syntheses in DMSO and DMF are discussed.

Two devices intended for copper cylindrical liner gasdynamic acceleration to velocities of 5–7 km/s using the chemicals explosion energy have been investigated. It has been demonstrated that the acceleration of quasi-isentropically and isentropically loaded liners under the conditions of high-level dynamics, symmetry of deposition, and suppression of shock-induced dusting is feasible.

When studying the process of shock-induced ejecta, in particular when particle jets move in a gas or are caused by several shock waves, it is necessary to obtain experimental data on the time history of density in these jets starting from the moment of shock-wave arrival at the free surface of the sample. In this work, such measurements were performed using flash radiography with synchrotron radiation. In the experiments, one or two successive shock waves with a pressure of GPa arrived at the free surface of tin samples with a roughness Rz of 5, 20, and 60. Shock unloading occurred in vacuum or gas (air, helium, nitrogen) at initial pressures of atm. The paper presents the experimental setups and experimental data on the density dynamics in ejecta formed after the arrival of one and two successive shock waves at the free surface of samples in vacuum and gas media.

In the development of special explosion-proof chambers that must meet strict requirements for strength reliability, an important issue is the choice of the material of the load-bearing shell subjected to pulsed (dynamic and shock-wave) loads. As a rule, these structures are made from industrial low-alloy steel pipes of various standard sizes. This always raises the question of choosing the steel grade, especially at the stage of design-basis justification of their explosion resistance, since the dynamic strength characteristics of the pipe material are generally unknown. This paper is the first to present the results of analysis of the static, dynamic, and shock-wave compressive and tensile strengths of 17G1S, 09G2S, 10G2FBYu, and K60 strength class pipe steels. In addition, comparative data are given on the explosion resistance of pipes of 09G2S and 10G2FBYu steels at a strain rate of   s .

The quasi-isentropic compressibility of a strongly nonideal helium plasma in the pressure range 250–600 GPa is experimentally studied in devices with cylindrical geometry. The temperature at the front of a cylindrical shock wave in helium ( T ≈ 10 000 K) and the flight speed of the inner cascade ( W ≈ 3.5 km/s), in the cavity of which the maximum compressed plasma density is achieved, are measured. Data on the compression of a nonideal helium plasma to a density ρ ≈ 3 g/cm 3 at an approximately constant final temperature of 21000 K are obtained. The trajectories of the metallic shells compressing the plasma are detected using high-power pulsed X-ray sources with a boundary electron energy of up to 60 MeV. The helium plasma density is determined using the radii of the shells measured at the time of their “stop.” The compressed plasma pressure is obtained using gasdynamic calculations. Comparative theoretical calculations of the quasi-isentropic compression parameters have been carried out using the following two theoretical models: the traditional chemical plasma model (SAHA code) and an ab initio quantum molecular dynamics (QMD) approach. No anomaly of the experimental data in the pressure range of the plasma phase transition theoretically assumed in helium is detected.

Random field simulation methods that can be used to simulate the stochastic structure of three-dimensional clouds are discussed. Examples of homogeneous random field realizations that reproduce one-dimensional distributions and correlation functions of experimental fields of stratus optical thicknesses are presented.

This work was performed to study the behavior of 45Ti–45Ni–10Nb and 43Ti–46Ni–8Nb–3Zr (at %) shape-memory alloys (SMAs) under the effect of severe dynamic deformation to use the obtained results to develop technologies based on SMAs. Cast alloys were used for the tests. The elemental and phase compositions of the alloys in the initial state, as well as the phase composition, kinetics, and temperatures of phase transformations after heat treatment (annealing in a vacuum at 850°C for 4 h, furnace cooling) have been determined. The mechanical and thermomechanical characteristics of these alloys before and after shock-wave loading have been determined.