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

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

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

Now elements of natural structures of the world surrounding us form a basis for loan by their architects and designers in their professional activity. It is caused not only by esthetic appeal of natural objects, but also big functionality of their form providing high degree of durability, reliability, adaptation to the changing external conditions, comforts of their use as inhabited and production rooms. In this work the analysis of the VAT of an oviform envelope under the influence of sole weight and intrinsic pressure is provided.

Keywords: intense strained state, finite element method, oviform envelope, sole weight, intrinsic pressure, analysis, efforts, deformation

Technical and economic indicators of different options of structural solutions of overlappings are compared. According to the results of the calculations, the most economic profitable option is determined.

Keywords: floor, reinforced concrete, ribbed, monolithic, precast, hollow, profiled, flooring, steel concrete, consumption, reinforcement, concrete, labor input

The questions of mathematical interpretation of results of trajectory measurements are discussed in terms of increasing the accuracy of identification of bearings of unmanned aerial vehicles during their movement in a "swarm" - a group. Variants of identification of horizontal and spatial bearings are offered. For each of the variants, criteria are proposed for identifying the belonging of the measured values ​​to the same object in the group and the conditions for achieving them. The situation of false positives is shown. It is determined that additional identification measures are needed to eliminate false bearing triads and uncovered ambiguities, including the use of combinatorial exhaustive search algorithms. For their study, it is necessary to develop an experimental statistical model with an algorithmic description of cause-effect relationships, which is a further development of this work.

Keywords: " unmanned aerial vehicle, group of objects, bearing identification, horizontal bearing, spatial bearing, identification criteria, false notch"

The article considers a method for optimizing circular ducts for ventilation and air conditioning systems. Universal dependencies are given to determine the diameters of the cross-sections of the air ducts and the air velocities in them that are technically and economically optimal. It is shown that the optimum air velocity in the section of the ventilation network does not depend on the site location relative to the fan of the system. Specific examples of determining the optimum diameters of air ducts and air velocities in them with the use of the dependences obtained are given in the technical and economic sense.

Keywords: Аir duct, aerodynamic calculation, ventilation system, air conditioning system, techno-economic optimization, optimal diameter, optimal air speed, energy saving, energy efficiency, aerodynamic efficiency

The problems of studying the mathematical interpretation of the results of trajectory measurements in terms of increasing the accuracy of identification of bearings of unmanned aerial vehicles during their movement in the group "swarm" and "system" are discussed. The variants of identification of horizontal (IHP) and spatial bearings (PPI) are proposed both separately and in a complementary application. Identification of bearings of similar objects in the swarm type group is expedient to be carried out according to the IGP-IPP algorithm. However, it is only partly operational at distances of 3 km or more. As the main algorithm for identifying bearings of similar objects in the "Story" group, it is advisable to use IPP. Although these algorithms achieve high identification efficiency under favorable conditions, with tougher conditions, they drop rather sharply. Therefore, to maintain a high level of probability of "pure" identification, it is advisable to use additional measures to combat false triads. For the removal of problems, it is necessary to develop and apply combinatorial algorithms for exhaustive search, which is the direction for the development of further research.

Keywords: unmanned aerial vehicle, group of objects, bearing identification, horizontal bearing, spatial bearing, identification criteria, false notch

The history of development of small hotels in different time periods is considered in the article: ancient Greece, the Middle Ages, pre-revolutionary Russia of the 17th-19th centuries. Two main historical forms of small hotels in Russia in the 18-19 centuries are compared: an inn and a tavern. The main approaches to studying the typology of small hotels in the Soviet Union are covered. Considered the changes that have occurred in the architecture of small hotels in recent decades. There are several important modern architectural models of small hotels (small hotel and complex of restaurant and hotel), as a return to the historical forms of small hotels (inn and tavern).

Keywords: Small hotels, architecture, inn, tavern, architectural model, architectural design, architectural typology, design principles, optimal capacity, functional areas, complex of restaurant and hotel

At present, more and more attention is being paid to the radiation safety of the population, in connection with this new devices are being modernized and modernized, to improve the state of protection of present and future generations of people from the harmful effects of ionizing radiation for their health. The article considers the key aspects in working with such equipment and suggests measures to reduce the risk of working with it, primarily for personnel, especially in emergency situations.

Keywords: Radiation, source, hot cell, radiation, safety, emergency situation, limitations, degree of radiation

The article is devoted of freight traffic in the regional companies is considered by the example of Ugtehmontazh. Deficiencies have been identified and a set of measures has been proposed that allows to optimize the process of freight traffic. Including the model of the process of cargo transportation by the example of Ugtehmontazh is developed. The introduction of the electronic system of applications allows you to reduce costs, increase the carrying capacity.

Keywords: freight transport, rolling stock, carrying capacity, logistics management, operations management process, transportation process model, lot size, loaded return, idling, transport process

This article describes the definition of the approximating function of deflections of building structures using the method of least squares.

Keywords: the approximation function, the least squares method, the deflections of structures, prediction of deformations, the deformation of the structures

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

Are represented the results of studies on the development of teploognezashchitnykh composition cement solution mixtures on the distended vermiculite and the pumice with the application of a multifunctional additive D -5. Are proposed the compositions of teploognezashchitnykh composition mortars, which make it possible to substantially improve the physicomechanical properties of solution mixtures and solution. The introduction of multifunctional additive D -5 to solution mixtures makes it possible to improve the properties of composition solution mixtures and to improve the characteristics of solution. The replacement of the fine dispersed fraction of the distended vermiculite d0,63 mm does not produce by pumice by the volume in the solution mixtures a noticeable increase in solution density, in this case their strength characteristics grow. The developed composition solution mixtures correspond to requirements ALL-UNION STATE STAN. 28013–98 and have low prime cost due to the use of the pumice

Keywords: portland cement, the distended vermiculite, pumice, additive D -5, teploognezashchitnyy composition solution, transverse strength and compression, the mobility of mixture, exfoliation property, the density

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