Особенности распространения стоячих электромагнитных и электронных волн в металлическом проводнике с электрическим переменным током проводимости

The paper demonstrates the results of approximate calculations on the establishment of basic features of the propagation of standing transversal electromagnetic waves (EMWs) and standing longitudinal de Broglie electronic waves in a homogeneous not massive non-magnetic metallic conductor of finite dimensions (the radius r0 and the length l0 >>r0) with the alternating axial-flow current of conductivity of i0(t) of different peak-temporal parameters. The correlation for the rated estimation of the average velocity of propagation of the standing transversal EMWs and standing longitudinal de Broglie electronic waves in a metal (alloy) of the indicated conductor is presented. It is shown that quantized standing transversal EMWs arising in a metallic conductor of finite dimensions substantially differ from ordinary transversal EMWs, propagated in the conducting environments of unlimited dimensions. An important feature of the standing transversal EMWs in the examined conductor is the fact that their tension of an axial-flow electric-field advances by a phase their tension of an azimuthal magnetic-field on the corner of π/2. It was established that in the standing transversal EMWs of the used conductor the energy of their electric field only passes into the energy of their magnetic field and vice versa. Therefore the standing transversal EMWs do not transfer the flows of the electromagnetic energy on the surface of the studied conductor.

Immersion ultrasonic transducers

The principles of operation and design of immersion ultrasonic transducers developed by the authors for excitation and reception of elastic vibrations in moving filament-like and plane-parallel materials, in particular, polymer fibbers and films, with an adjustable angle of input (reception) of probing signals into moving controlled object – polymer fibbers and films at normal and high temperatures. The technical characteristics of the installation are given in which the converters developed by us are used, namely, sounding base (distance from the emitter to the receivers), the duration of the probing pulses, the frequency of filling and the duration of the probing pulses, the speed of the controlled object, the combined standard measurement uncertainties of the difference Δt of the propagation times of ultrasonic waves from the emitter to the first and second signal receivers, relative combined standard uncertainties of measurements of attenuation coefficient and velocity of propagation of ultrasonic waves.

On the question of mathematical modeling of the plasma deposition process in the restoration of agricultural machinery parts

This article deals with the mathematical description of technological processes of plasma spraying, which has recently been actively used in the repair and restoration of friction parts of agriculture. The influence of elastic wave velocities on the physical-mechanical and thermophysical characteristics of plasma sputtering is studied. In the course of the study, equations were developed that determine the velocity of propagation of elastic waves in a two-component medium under plasma sputtering.

Anti-vibration - stabilizing drill bottomhole assembly for «Perfobore» technical system

The article discusses the method of bottomhole assembly (BHA) for the «Perfobore» technical system, investigated as a complex of elastic-viscous working elements - coupled oscillators located in a dynamically disturbed section of the assembly. The length of the section is determined using the group velocity of propagation of the energy of a packet of quasi-harmonic waves differing from each other in phase and frequency, with prevailing natural frequencies, which are calculated after statistical processing of the obtained dynamograms of phase trajectories. Then, the working elements of the technical system are assembled with selected natural frequencies and taking into account various bending and torsional stiffnesses of the component assemblies (oscillators), and the damping properties of the assemblies are enhanced by the additional placement of hydromechanical axial load regulators with a variable vibration isolation coefficient in the calculated places of the «motion stability nodes».

RESEARCH OF THE RELATIONSHIP OF THE RATE OF ULTRASOUND IN METALS WITH THEIR IMPACT VISCOSITY AND HARDNESS UNDER THE CONDITIONS OF REDUCED TEMPERATURES

The paper presents the results of the study of the relationship between the velocity of propagation of longitudinal waves in a metal with the values ​​of impact toughness and hardness in a wide range of low temperatures. It’s been found that with a decrease of temperature, an increase of hardness, a decrease of impact toughness and an increase of the velocity of propagation of a longitudinal wave in the studied metals are observed, and the velocity of propagation of a longitudinal wave has a close correlation with the characteristics under consideration. An increase of the speed of sound with decreasing temperature, in our opinion, is explained by an increase of the thermal conductivity of metals. Thus, by the values ​​of the speed of sound propagation in metals, it is possible to predict the level of its impact toughness, as well as hardness at low temperatures, and, consequently, the tendency to brittle fracture of structures.

Calculation of Wave Velocities in Segmented Pipelines with Flexible Joints

Engineering methods for finding the average (averaged) velocity of propagation of longitudinal waves in pipelines with flexible joints are presented. By accurate analysis of the problem of oscillations of a one dimensional periodically inhomogeneous structure it is shown that the results of engineering approaches for rod velocity are the first or long-wave asymptotic approximation which valid when the period of external influence (the length of the seismic wave) significantly exceeds the size of the periodicity cell of the pipeline (the length of the pipe with a joint). Thus, it is established that when this condition is met, the problem of pipeline dynamics with joints is reduced to a much simpler problem of vibrations of a homogeneous pipeline, the velocity of wave propagation in which is equal to the found average value. Numerical examples are given that demonstrate a significant (sometimes by an order of magnitude) decreasing of the rod velocity in the presence of flexible joints.

Effects of Two-Temperature, Rotation, Initial Stressed Magnetic Field on Rayleigh Wave in Half-Plane

In the present paper, we consider the governing equation for generalized thermoelastic media under the effect of magnetic fleld, rotation, initial stress, and two-temperature parameter for Rayleigh wave in half-space. The secular equation of Rayleigh wave is also deduced using surface wave solution, which also satisfy the radiation condition for thermally insulated/isothermal surface. The velocity and amplitude attenuation factor of Rayleigh wave is also computed for a particular material. The effect of two-temperature, rotation, and initial stress parameters on velocity of propagation and amplitude attenuation factor is shown graphically.

A Study of Transverse Buckling Effect on the Characteristics of Nuclides Burnup Wave in a Fast Neutron Multiplying Media

A study of transverse buckling effect on the characteristics of nuclides burnup wave in multiplying media (cylindrical geometry) has been carried out. The burnup wave is characterized in terms of velocity of propagation, transient length (TL), and transient time (TT) in establishing the burnup wave and full width at half maximum (FWHM) in the established region of the wave. The uranium–plutonium fuel cycle is considered. The sensitivity of the results is studied for different radial buckling led leakage of neutrons. It is discovered that the velocity of the wave increases with the increase in the radius of the cylinder (i.e., reduction in the transverse buckling and hence increase in radial neutron leakage). FWHM is relatively insensitive to radial neutron leakage. The transient time and transient length are very large for smaller radius; these decrease with the increase in radius. The study provides insight on the build-up of burnup wave in the neutron multiplying media and brings out the importance of transverse buckling led radial neutron leakage on the characteristics of fuel burnup wave in multiplying media.