The technologies for producing ultrafine copper powders are examined. The influence of various parameters on the processes of electrocrystallization of particles is studied. Various mechanisms for producing particles in the presence of water-soluble polymers are presented. The ultrafine copper powders obtained using different electrolysis modes. A review of advanced electrochemical methods for producing ultrafine copper powders with the addition of various stabilizers particle growth, further ways of developing the technology of these technologies are highlighted.
Keywords: ultrafine copper powders, electrocrystallization, production methods, particle stabilization, water-soluble polymers, double electric layer, vibrocathode
A method for the intellectualization of measurement procedures has been developed. It is based on the step-by-step optimization procedure, which provides a reduction of the stochastic estimation problem to a number of deterministic problems. The task of the first stage of optimization is the synthesis of an adaptive mathematical model of the measuring process based on the combined principle of maximum, which, unlike the known methods, will ensure the constructiveness of its use in the next stages of optimization. The task of the subsequent stages of optimization is to solve the estimation problem based on the regularization method A.N. Tikhonov. Equations of an iterative measurement procedure are obtained that differ from the state transition vector functions known in structure. It belongs to the category of intelligent measuring procedures, since it makes a targeted choice of the closest to the true value of the assessment of the measured parameter in the conditions of structural uncertainty of the model of the studied object and parametric uncertainty of the observation model.
Keywords: two-stage synthesis, intellectualization, the combined principle of maximum, regularization
The paper describes the implementation of a fiber-optic single-channel vibration sensor built on the basis of two fiber Bragg gratings, a broadband source, a photodetector and a sound card of a computer used as an ADC
Keywords: vibration, fiber optic sensor, fiber Bragg grating, Fourier transform
The complexity and high cost of multiplexing optical fiber sensors is still the main limitation for the widespread introduction of sensory systems, both distributed and quasi-distributed, and point-like. The article proposes a new multiplexing method that takes advantage of both broadband and two-frequency radio-photon multiplexing systems. The simplest broadband radiator is taken from the first, but a complicated and expensive system of spectrometry is not used to determine the central wavelength of fiber Bragg gratings. From the second, a recording system is used at the beat frequency between two components, but an expensive system for generating two- and polyharmonic probing systems is not used. The multiplexing parameter is determined by the frequency of separation between the transparency windows of a fiber Bragg grating, for example, with two phase π-shifts, which differs by a certain value for each of the sensors. The mechanism of modeling of gratings of the specified type is given, in principle the possibility of multiplexing of various number of sensors is shown. When using sensor networks built on the basis of passive optical, the number of multiplexed sensors can reach 256, with all sensors having the same Bragg wave of the wave, and can be combined into tree, bus and other topologies.
Keywords: fiber Bragg grating, phase inhomogeneity, fiber optic sensor, multiplexing, transparency window, frequency difference between transparency windows, beat frequency
The article presents the results of an experimental research on the effect of the pulsating mode a capacitive heat exchanger with an active pipe part on the convective processes heated fluid. Described dignity capacitive heat exchangers. The research was conducted using a thermal imaging surveys. Compares two modes: stationary and pulsating. The method of experimental data processing, based on the analysis of fluid layers. A regression analysis allows to determine the dependence of the relative distribution of the temperature difference between the layers of fluid in the studied mode. The obtained regression equations were presented in the form of an exponential function and harmonic. The effect of pulsing regime on the process of convection in the upper quarter of the heating zone in a capacitive heat exchanger. The study showed the advantage of the capacitive heat exchanger with an active pipe part is often compared with the classical heat exchanger in part the speed of convective processes in the fluid to be heated.
Keywords: capacitive heat exchanger with an active pipe part, pulse heating system, convective process