Vol 51 Iss. 3

The limits of the applicability of the concept of viscosity. In molecular physics, it is shown that the phenomena of diffusion, thermal conductivity, and internal friction in gases are based on a single mechanism – the transfer of mass, energy, and momentum from one gas layer to another by chaotically moving molecules. This commonality of the mechanism is manifested in the presence of a connection and mutual proportionality of the coefficients of diffusion, thermal conductivity and internal friction – viscosity. ...

The developed theory of mineral liberation makes it possible to calculate all the main parameters of the beneficiation process to obtain products of a given quality, provided the technological methods fully achieve the effect of a given comminution depth. In fact, the qualitative and quantitative indicators of existing coal beneficiation processes differ significantly from the theoretical ones. This is explained by the insufficiently clear separation of particles with similar specific gravity and the impossibility of reliable beneficiation of fine coal size classes. Therefore, it is important to choose the correct cut density, at which the beneficiation will be optimal. Most coals, in particular, those of the Donetsk basin, are usually beneficiated at a specific gravity of 1.5; however, in some concentrates the ash and sulfur content remains high. ...

In recent years, a new field of knowledge has developed — geoacoustics, which combines a complex of acoustic methods intended to solve mining and geophysical problems. Depending on the specific tasks, the frequency range used covers the range from fractions of a hertz to megahertz. Modern geoacoustics is developing in several directions: sound ranging, acoustic logging, modelling of seismic processes, and ultrasonic methods for studying the stress state of rocks. ...

In resonant measurements on longitudinal vibrations, the modulus of longitudinal elasticity E (Young's modulus) is determined, and on torsional vibrations – the shear modulus G. For a rock sample in the form of a rod with free ends …

In recent years, dichroic polaroids have been widely used to produce polarized light. Their advantages are comparative cheapness, small thickness, and large linear and angular aperture. The main disadvantages are the following: transmission is selective across the spectrum, as a result of which the spectral distribution of energy in the light beam under study is significantly distorted. ...

The problem of studying physical phenomena during an explosion is currently very topical. Some processes during an explosion have durations so short that only electronic equipment can record them. The presence of a pronounced piezoelectric effect in some crystals, as well as in all ferroelectrics, makes it possible to develop low-inertia methods for measuring pressures, including shock wave pressure. Piezoelectric sensors have been used to study shock waves both in our country and abroad. ...

In the conditions of mining enterprises, the communication channel is usually the weakest link in the information transmission system. Frequent violations of mining, geological and climatic conditions lead to its damage and, consequently, loss of information. Therefore, when measuring in hard to reach places and dangerous conditions, it is necessary to use communication channels that would be minimally affected by changes in external factors (for example, rails, pipes, grounding busbars, trolley wires or specially laid steel cables). ю..

The methods and technical means of mineral exploration are very diverse. One of them is the method of recording radiance (brightness) contrasts of the Earth's surface in the infrared region of the spectrum, which, in combination with others (photographic, magnetometric, etc.), can provide useful information. The article discusses the physical conditions for the existence of radiance contrasts caused by inhomogeneities in the structure of the Earth's layers, as well as some issues concerning the possibility of recording and calculating them. ...

The most well‑known focusing system for a beam of paramagnetic atoms is a six‑pole magnet. However, the design and technology of its manufacture are relatively complex. In this article, a comparatively simple magnetic focusing system is proposed...

Atomic and molecular beams are widely used in a number of quantum electronics and radio spectroscopy devices. The use of intensity modulators in these devices would simplify the task of beam detection, since amplification of weak alternating signals is technically simpler than of direct ones...

The causes of optical coloration of ferroelectric barium titanate single crystals vary. For example, impurity coloration appears during crystal growth; dichroic coloration results from the absorption of polarized light passing through the crystal. Specific coloration of single crystals also arises from the interference of ordinary and extraordinary rays propagating in the crystal, as well as from the dispersion and diffraction of light. ...

The issue of measuring the refractive indices of nickel carbonyl has been addressed in only two papers. However, the purity of the samples used for measurements is not indicated in them; measurements were carried out for a small number of spectral lines and in a limited temperature range. ...

The cross section of the nickel carbonyl oxidation reaction was measured by studying the kinetics of the reaction. The amount of reacted substances was determined by the appearance of oxidation products in the reaction chamber by the optical method. As is known, the oxidation products of nickel carbonyl ...

When obtaining powdered nickel by the carbonyl method, at the intermediate stage it is necessary to monitor the degree of purification of nickel carbonyl from iron carbonyl. Currently, the content of iron carbonyl is determined by chemical analysis lasting 6‑8 hours. A faster method for monitoring the content of iron carbonyl in the product is proposed – an optical one, which can be made the basis of an automatic analyser...

Interest in studying the polarization of spectral lines by electron impact has increased significantly recently. This is especially true for measurements near the excitation threshold. ...

In recent years, various properties of low‑temperature gas‑discharge plasma have been increasingly used in gas‑discharge devices, quantum amplifiers and oscillators, various light sources, plasma generators, etc. …

Many phenomena in solids are associated with vibrations of their crystal lattice. The nature of Raman scattering and infrared absorption is almost entirely determined by the phonon spectrum of the crystal. Therefore, to study these phenomena, it is necessary to know the lattice vibration frequencies (phonons). ...

If light from a continuous spectrum source is passed through an interferometer, and the resulting horizontal interference fringes are projected onto a vertically arranged slit of a spectrograph, then each interference fringe will be spread into a spectrum ...

In recent years, new photographic emulsions and other photosensitive materials for holography have been developed with resolutions ranging from hundreds to several thousand lines per millimetre. New methods and appropriate instruments have been required for the resolvometric testing of such emulsions, since projection resolvometers are unsuitable for testing at spatial frequencies above 600‑1000 lines per millimetre...

The electrophysical properties of materials are influenced by many factors: moisture content, temperature, grain-size and chemical compositions, etc. Therefore, the total differential, for example, of the volumetric resistance of saltpeter can be represented as an equation. Similar equations can be written for capacitance and dielectric loss factor.. ...

It is known that dissolved salts change the vapor pressure saturating the space above the liquid. There is no data in the literature on changes in mercury vapor density over amalgams. However, this phenomenon is of interest, since amalgams may form on the electrodes of a number of gas-discharge devices, affecting the density of mercury vapor, upon which the operation of the device depends. ...

As is known, alkali metal vapors ionize on the clean surface of a foreign metal if the work function of the latter is greater than the ionization energy of the alkali atom. This phenomenon is explained by the attainment of thermodynamic equilibrium in the metal surface – atom system during collisions...