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
In July 2017 marks the 10th anniversary of the publication of the first issue of the scientific journal "Inženernyj vestnik Dona (Rus)". I would like to wish all the authors, members of editorial Board and editorial staff new exciting discoveries and publications, creative achievements for the benefit of the development of Russian science and industry!
Keywords: anniversary, achievement, congratulation
This paper presents an analysis of the development process of the electronic scientific journal "Inženernyj vestnik Dona (Rus)". Conceptually, the journal reflects a new culture of scientific publications based on global and mini Internet platforms. It is shown that the basic advantage of an electronic journal is achieved through the implementation of an open access initiative. From the date of publication, the material is available for the widest possible range of readers. This imposes additional reputational risks on authors and on the journal as a whole, motivates mutual responsibility. Conceptually, the journal "Inženernyj vestnik Dona (Rus)" focuses on the traditional branches of engineering knowledge. The journal supports publications in the light of convergence of engineering methods and professional and scientific competencies of specialists in various fields of science. The journal represents a kind of interdisciplinary scientific engineering forum. The journal implements the initially adopted principle of "development based on science."
Keywords: electronic scientific journal, Internet platform, interdisciplinarity, open access, concept, results
The article examines not only the issues of ensuring mutual understanding and interaction of subjects of innovative engineering, but also the need for creative development of their consciousness. Attention is paid to the increasingly popular in the invention, in the technological business and innovative engineering of critical thinking and the possibilities of its constructive use. In the final article, the authors derive an algorithm for searching for creative solutions.
Keywords: dogmatism, criticism, creativity, constructivism, search for creative solutions
Diffraction characteristics of the gratings are calculated by two methods - method of approximate boundary conditions and a strict method based on the numerical and analytical solution of the two-dimensional integro-differential equation. Results of the graphene diffraction gratings calculations are presented.
Keywords: graphene, graphene gratings, volume integral equations, plasmons, coefficient of reflection
An analysis of the mechanisms limiting the growth of the output characteristics of ion recombination He-Ca lasers with an increase in the active medium volume and frequency of pulse repetition is carried out. It was established that by a growing laser tube diameter and a growing frequency of pulse repetition the average power of He-Ca lasers saturates and then decreases due to the formation of radial non-uniformity of the active medium as a result of its overheating on the axis and of the radial cataphoresis, as well as because of the raise of the electron temperature level in early afterglow, conditioned by the grow of gas temperature. It is pointed out that as possible ways of increasing the output characteristics can be used the blackening of the laser tube surface, the use of an independent input of calcium vapours, the use of a forced cooling, while the application of a tube with rectangular cross-section will allow to maximally increasing the energy characteristics. Based on numerical computations it is shown that the attainable maximum of running power of He-Ca lasers amounts to: ~ 4.4 W/m for self-heating active elements from BeO-ceramics and ~ 5.2 W/m – on blackening their surface; ~ 5.3 W/m for an independent calcium vapours input and ~ 6.2 W/m – for its combination with blackening; ~ 9.5 W/m for an intensive forced cooling of active elements with cylindrical geometry; ~ 16 W/m – with active elements of rectangular cross-section at a ratio of wall sizes 1:3.
Keywords: metal vapor laser, the ion recombination He-Ca laser, pulse-periodic discharge, gas-discharge plasma, self-heating regime, mathematical modeling
One of the most important advantages of the ion lasers based on the ion transitions of metal vapors and noble gases, is the high quality of radiation (high monochromaticity and coherence). However oscillation on each of active media takes place on restricted number of laser transitions. The purpose of this work is receiving a laser radiation at the same time on several quantum transitions in the wide range of wavelengths when using mix of several active mediums. That increases a set of the laser lines radiated by one laser. The characteristics of ion laser transitions (gain, power, noise level) are substantially improved if a hollow cathode transverse-type discharge is used for pumping of the laser transition, and such method of a pumping was used in this work. It was experimentally found the discharge conditions providing various ratio of laser output power on various laser lines for laser on mixture of helium with cadmium and mercury vapors in which the population inversion and laser oscillation are carried out on mercury ion transition with the wavelengths of 615nm (red), and on cadmium ion transitions with the wavelength of 533,7&537,8nm (green) and 441,6nm (blue), and also for laser on mixture of helium with mercury vapors and krypton which lasing on 431,8nm and 469,4nm blue-green krypton ion lines and 615nm red and 794,5 nm IR mercury ion lines. The studied lasers can be useful at information processing, in a metrology, etc.
Keywords: ion metal vapor laser, hollow cathode discharge, the combined active media
The method of control parameters of electro-acoustic transducers of the piezoelectric type, composed of an acoustic antenna arrays by electrical measurements is described. A convenient practical implementation of this method by determining the integral of active component of conductivity (area under curve) is proposed .
Keywords: acoustic antenna array, electro-acoustic transducer, piezoelectric element, control of parameters
Theoretical studies of the temperature distribution during laser heating of the TiO2 precursor film on the FTO/glass substrate have been carried out. The simulation was performed on the basis of a numerical solution of the heat equation in the Matlab program to determine the energy density of the laser radiation necessary for crystallization of TiO2. It was shown that on the surface of the TiO2 precursor the temperature reaches a maximum value at a time point of 133 ns with the Gaussian temporal form of the laser pulse. The optimum energy density for crystallization of the TiO2 precursor film with the nanosecond pulse duration is 1.3-1.6 J/cm2, when the film thickness temperature corresponds to 400-500 °C. The obtained results of the simulation are consistent with experimental studies.
Keywords: numerical simulation, laser heating, temperature distribution, TiO2 film, solar cell
The use of low-temperature plasma in industry and the social sphere is given serious attention in Russia and abroad. Plasma technologies are environmentally friendly and allow solving the problems of resource saving and energy saving. The article is devoted to the search for directions for using low-temperature plasma and the creation of appropriate technologies and equipment in industry and the social sphere. Based on the analysis of scientific, technical and patent information, the opinion was expressed that the potential of low-temperature plasmas in forestry and in the timber industry is underestimated
Keywords: Low-temperature plasma, industrial and social applications, forest seeds, pre-sowing treatment
Numerical solution to the problem of heat transfer in boundary layers transparent Strip on the walls, exposed on the opposite side of the radiant-convective heating. Study of influence of mode parameters on heat transfer process of tasks carried out in the case of the gradient flow and included the most typical variants of transportation processes. The purpose of the real work is studying of processes of transfer at non-linear boundary conditions, obtaining approximate and analytical decisions non-linear warm and a mass transfer, establishment of communication between regime parameters and physical interpretation of results of a research. Also some conjugate problems of heat exchange in the presence of radiation are studied. The analysis received decisions is carried out. The executed research allowed to establish that existence of a transversal overflow of heat in a wall and also the radiation of a surface have significant effect on the nature of distribution of the surface temperatures.
Keywords: boundary layer, convection, radiation, gradient flow, conjugate heat transfer
Hot stamping of porous preforms is considered. Structural steels obtained with the technology of hot stamping of porous blanks are much inferior in terms of machinability by cutting similar cast and hot-rolled steels to the chemical composition. The reasons for the poor machinability of cutting structural steel powders are given.
Keywords: powder metallurgy, hot forging of porous preforms, machinability by cutting
High-density powder steel obtained with the technology of hot stamping of porous blanks is much inferior in terms of machinability by cutting similar cast and hot-rolled steels to the chemical composition. The paper considers the ways of possible improvement of machinability of structural powder steels.
Keywords: Powder metallurgy, hot forging of porous preforms, machinability by cutting
In operation the optico-acoustical effect which leads to excitation of acoustic waves in case of absorption of a variable luminous flux is considered. The model of calculation of the acoustic field generated by a laser study in liquid in case of hit on cylindrical objects in liquid is offered. The special nanomaterials added to liquid can serve as cylindrical objects. It is set that the optoacoustic effects watched in the liquid environments are beyond the fundamental developed models for the ideal environments and require more detailed reviewing and specification.
Keywords: optoacoustics, optoacoustic waves, bioliquid, virtual device, cylindrical, spherical absorbers, nanofibres
The use of chalcogenide glass as immersion environments on the partitioning in the production of cut diamonds. The work can be useful for specialists in the diamond businesses.
Keywords: optics, optics of anisotropic media, immersion medium, not faceted diamonds, recognized by optical defects in diamond, chalcogenide glass, the spectral characteristics of chalcogenide glass, the visualization system
Improving the performance of tools by improving their structural condition by method of boriding and heat treatment will ensure the rational use of expensive high alloy materials for the manufacture of cutting tools with working part having a high mechanical and operational properties, which, of course, is an urgent task for the modern machine-building production.
Keywords: cutting tools, chemical-heat treatment, method of boriding
The technique of calculation of high-altitude temperature profile of electrons in the region E of the ionosphere of the Earth consided. Presented examples of the calculation of the profile of the electron temperature at altitudes of 100 - 170 km, depending on solar Zenith angle given. Discusses the problems of the heat balance of the ionospheric electrons of Earth.
Keywords: ionosphere electron temperature, concentration, heat balance, the heating rate, solar radiation, collisions of electrons, high-altitude temperature profile, probe measurements
In the paper, we give a brief overview of the main developments made personally and under the direct supervision of the professor, academician RANS andIAELPS P. Kudryavtsev. These developments are devoted to the use of sol-gel processes in various branches of science and technology. Using this process, new composite heat-resistant materials, highly disperse materials and thin filmswere created. These developments have made it possible to create new efficient catalysts and highly selective inorganic ion-exchange materials. Based on inorganic ion-exchange materials, a technology was developed to extract lithium from natural brines, which are poor in lithium content. On the basis of sol-gel technology, new composite matrix-isolated flocculants-coagulants were created. These reagents are designed for the treatment of natural and wastewater in order to remove impurities of oil products and heavy metals.
Keywords: Nanomaterials, Sol-Gel Technology, Nanostructured Materials, Composite Materials, Highly Dispersed Materials, Thin Films, Catalysts, Highly Selective Inorganic Ion Exchangers, Extraction of Lithium, Composite Flocculants-Coagulants
Gas-powder dynamics within the off-axis nozzle of the Precitec YC52 laser cladding head (Germany) has been studied using the original Tepler shadow setup, the high-speed tracing system and the laser Doppler anemometer. The length of the laminar part of the gas-powder flow has been optimized for variety of the transport and shielding gas flow, as well as the diameter of the orifice of cyclone. Powder jet at the nozzle’s outlet follows the carrier gas flow structure. In case of 4 mm nozzle’s diameter, the powder stream separates into two stable vortex structures near the surface of the substrate, causing significant losses of powder particles (about 2/3 of the total powder mass) within the melting zone, which finally reduces the efficiency of the deposition process and the powder utilization. Practical recommendations on the application of the optical diagnostic to optimize gas-powder jets for laser cladding are provided.
Keywords: laser powder cladding, shadow method, off-axis nozzle, tracing, laser Doppler anemometry, gas-powder flow optimization
An algorithm for numerical simulation of optical structure disturbance of biomedical objects is described. The key features of the presented algorithm are: posterization of CT or MRI scans, subsequent encoding and manual identification of each biological tissue, assigning it tabular optical properties. The described algorithm can be used in diffuse optical tomography (DOT) for numerical simulation of optical properties of biomedical objects of their constituent with variable spatial resolution. Numerical simulation showed that the presented algorithm allows us to describe the optical structure of biological tissue with data validity >90%.
Keywords: optical properties of biological tissues, time-resolved diffuse optical tomography, forward problem, turbid media, posterization
Laser tracking locators have certain drawbacks, among which there is a strong influence of the atmosphere on their energy and precision parameters, the process of aiming a narrow beam at the object, etc. High requirements for locators (the error of measuring the range to a few centimeters) lead to the need to take into account the state of the atmosphere on the route for application Corrections in the measurements. In particular, the phenomenon of refraction leads to a significant distortion of the signal. To reduce the error of distance measurements it is advisable to use methods to compensate for the effect of refraction or to take it into account and use the correction coefficients. The article shows that the effective solution to this problem in the absence of the possibility of obtaining operational and accurate information about meteorological parameters is the use of parallel laser probing of the atmosphere. More promising in this case is the use of laser methods for controlling atmospheric parameters, which we described and experimentally investigated at the Chauda, Feodosiya, and the Republic of Crimea provinces. The obtained atmospheric data were used to create a mobile laser-television locator for external-trajectory measurements of the descent of the aeroelastic systems "Kafa" and were installed both on the ground and on an air balloon. The trajectories of the descent of balloons and cargo parachute systems were studied.
Keywords: Laser tracking locator, ranging channel, atmospheric effect, refraction, model compensation method, laser probing