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Magnetically stabilized fluidized beds are widely used in various technologies. The study given considers the use of this physical process in the iron ore beneficiation to obtain high-quality magnetite concentrates. For this purpose, a number of devices having different capacities have been developed. A modified Todes formula is proposed to be used to control the process of separating the components of ferromagnetic suspensions in devices of different capacities operating at present, using a mathematical model predicting the porosity and height of the fluidized bed.

Using the algorithm and the results of laboratory studies on grinding of loparite ores from the Lovozero deposit in a ball and rod mill, simulation grinding models were designed based on the transformation of a discrete function of the density distribution of outputs of mineral particle size classes. The model’s adequacy was quantitatively analysed carried out by calculating the determination coefficient without taking into account the constant component of the distribution; for a qualitative assessment of the result the authors used the Cheddock scale. The authors studied the minerals disintegration at ball and rod grinding with the following verification of the proposed algorithm. To identify the distribution of loparite by size classes in the initial ore samples and in the samples obtained in the disintegration taking place at different productivity, the X-ray diffraction analysis and the combined (weight, optical and geometric) methods were used.

Tests of ballistic aircraft on rail tracks in conditions close to real ones are an economically viable alternative to flight tests. Rocket rail tracks exist in the USA, Canada, France, China and a number of other countries. The article con-siders potentially self-oscillating mechanical systems that have a threshold mechanism for the transition from a noise vibrational stable state to a self-oscillatory one, depending on the mode parameters. An algorithm for estimating the damping coefficient of the harmonic components of a particular mode of a complex process is proposed. As an indicator of energy loss of the oscillatory component during resonant interaction, the value of the density of the power spectrum related to the width of the frequency range is taken. Based on the solution of the Fokker-Planck equation for a stochastic process, estimates of the “drift” and “diffusion” coefficients are obtained. A technique for estimating the state of potentially self-oscillatory systems in the form of a set of probabilistic stochastic characteristics is proposed. According to the experimental data of vibration accelerations for the structural elements of the rocket sled with the test object, according to the proposed method, it is possible to make the contribution of the self-oscillations of the elements, if they are pre-sent in a complex vibration process, and also to make estimates of their vibration strength at resonances.

The increase in the speed characteristics of newly developed aircraft models im-poses new requirements on the test bench equipment of rocket-rail tracks, including braking means. In this paper, the method of friction braking in the conditions of a rocket track is considered. A method for calculating the mode of motion of a rocket sled during friction braking and the thermal wear of the friction elements of braking devices occurring at the same time is presented. An example of the calculation of the friction braking of a conditionally specified rocket sled, per-formed according to the presented method, is shown.