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CONTENTS Introduction 1. Dose rate of gamma and neutron radiation in the cyclotron facility 2. Ionizing radiation in radiochemical laboratory and personnel doses 3. Radiation sources in PET department and their contribution in personnel radiation exposure 4. Doses of patients under performance of PET/CT study Summary more...

Ultrasonic devices created by the development team are presented, designed to increase the efficiency of various technological processes in laboratory research and the organization of new production. It is shown that the determination of the optimal regimes and conditions of ultrasonic exposure allows the selection of devices based on operating frequencies and intensities of exposure. Providing the necessary conditions for scaling and implementation of optimal regimes and conditions of exposure provides a simple transition from laboratory research to the implementation of processes on an industrial scale when organizing large-scale production. more...

The efficiency of value added chains (product chains) largely depends on the interaction quality between subjects, located both in different links of these chains, and inside these links. The business communication tools and technologies evolution ensures the continuous development of information processes’s organization forms and methods occurring within product chains and the entire subjects interaction system integrated into them. The achieved level of information infrastructure’s development and information and communication technologies makes it possible to improve fundamentally the quality of intersubjective interactions between the participants associations’s integrated through the product chain digital ecosystem formation and the inclusion in it of all interacting subjects. Digital systems as a form of subjects informational coexistence and interaction integrated into the product chains of the agro-food complex require justification of their functionality, formation principles and provisions reflecting the industry specifics of the intersubjective interactions organization. more...

Satellite quantum communication is the technology that allows to deploy large-scale quantum networks with a communication range of thousands kilometres We report the ground receiver for downlink quantum key distribution (QKD) with satellite. An optical part of this system including an active tracking loop is mounted on a 600-mm Ritchey-Chretien telescope and permits to distinguish polarization states to perform QKD between ground and satellite. Moreover, a procedure of calibration the receiver using stars with known brightness is presented. Measurements of the photon count rate of stars in the spectral range of 845 nm - 855 nm are performed and compared with an estimate. more...

Artificial satellites employed as trusted nodes can increase the distance between two parties to establish quantum key distribution (QKD), unlike fiber based communication lines that are limited up to a few hundred kilometers. This report summarises our progress on a ground receiver for satellite QKD and its tracking receiving system (TRS). The authors demonstrate the operation of the TRS in practice and achieve standard tracking error of 1.4/Ltrad observing four satellites over 80% of the time they were available. The optical signal, which was the sunlight reflected of low Earth orbit satellites, was attenuated to a single photon level and was detected effectively using avalanche single photon detectors. The authors have thus proved that the developed system is capable of stable reception of quantum signal from a satellite. © Published under licence by IOP Publishing Ltd. This work is supported by Russian Science Foundation (grant No. 17-71-20146). more...

Under consideration is the optimization problem for the routes of heterogeneous vehicles serving a given set of customers. It is assumed that the customers are represented by points in the plane, whereas the number of each type of vehicles is limited. To solve the problem, we developed a hybrid local search algorithm with coding the solutions as a sequence of customers. To decode the sequence, the corresponding NP-hard problem is solved by the method of Lagrangian relaxation. We propose new procedures for intensification and diversification of the search, as well as a new neighborhood of exponential size. The results of computational experiments are presented for the available test instances with the number of customers up to 255. For 15 instances we obtain new record values of the objective function. more...

The paper presents the development and determination of demands to the experimental setup for research of the effectiveness of ultrasonic intensification of gas component absorption by liquid. The theoretical studies of absorption kinetics carried out for the determination of requirements to the setup. Determinated requirements based on the theoretical results for the geometrical dimensions of technological volume, which will be place for absorption process, the oscillation frequency, power of ultrasonic transducer, the area of the radiating surface, the fluid flow in absorber and pneumatic pressure of absorbed gas. In accordance with the determined requirements, the proposed, developed and realized the setup, which can be applied to determine the modes and conditions of ultrasonic influence for maximum absorption efficiency. more...

Results are given for development of crystalline α-Al2O3 phase, crystal dimensions, degree of corundum phase crystallization microstructure, powder specific surface, and particle size distribution, obtained in the course of combustion of components in dry mixes using aluminum powder and different oxidizing agents. Aluminum powder combustion in the presence of oxidizing agents in the field from potassium nitrate to potassium perchlorate facilitates formation of broader, crystalline, and simultaneously intense diffraction maxima for α-Al2O3 phase. This is reflected in smaller crystal sizes and degree of corundum phase crystallization. Development of powder microstructure is governed by densely sintered particles, consisting of soft and hard agglomerates. It is relatively porous in the course of combustion with participation of strong oxidizing agents. This shows up as a less developed specific powder surface and wider particle size distribution, located in a field of coarse fractions in the range 5 – 54 μm, in contrast to powder prepared using potassium nitrate, whose particle sizes are located in the range 0.5 – 1.2 μm. more...

A procedure is provided for rapid climatic testing of fireproofing materials. According to test results, the best survival rate and climatic stability is demonstrated by fireproofing foaming composition SGK-2. This composition is recommended for use as a fireproofing coating for metalwork of gas pumping equipment for prolonged (up to 20 years) operating life. more...

Phase composition, crystal size development in powder, and microstructure are studied, and data are summarized for specific surface and particle size distribution of corundum powder prepared by self-propagating high-temperature synthesis (SHS) from solutions in relation to the oxidizing agent:fuel molar ratio. A considerable reduction is revealed in intensity of α-Al2O3 phase crystallization with an increase in the amount of fuel to the ratio 1:1:2 and a reduction in crystal size of this phase in powder. A reduction in powder specific surface and formation of powder particles with sizes of 20 – 400 μm with a ratio of 1:1:1.5 is demonstrated. Addition of thiourea with a ratio of 1:1:2 does not facilitate combustion. With a ratio of 1:1:1.5 there is a greater practical yield of corundum powder than with a ratio of 1:1:2. more...

The article considers the problems of the development and the application of the technological volumes used as a part of the ultrasonic technological apparatuses at the intensification of the technological processes in a running mode. Proposed approaches to the design and application of the technological volumes allow developing the ultrasonic apparatuses with necessary parameters of ultrasonic action — power, intensity of radiation, frequency, radiating surface in order to provide specified productivity of the processes. more...

The article is devoted to the creation of ultrasonic equipment for researching of erosion resistance of various materials to cavitation. Results of research of functional properties of created ultrasonic device are provided. more...

The article is devoted to the studies of ultrasonic cavitation action on the process of parts cleaning from burrs in out-of-the-way-places with the application of different media including abrasive suspensions and chemically active media. more...

This paper proposes a new approach to improve the efficiency of coagulation of dispersed particles in liquid. The approach is based on the ultrasonic treatment as a sequence of wave packets (ultrasonic pulses) of finite duration that is less than cycle period. The impact of ultrasonic pulses reduces the maximum cavitation nuclei radius achieved during direct diffusion of dissolved gas into the cavitation bubble interior. This leads to an increase the threshold intensity required for cavitation and hence to increase the maximum allowable ultrasonic energy that permits particles coagulation at stable cavitation absence mode. To determine the optimal ultrasonic pulse exposure modes (intensity and pulse duration) to ensure the most effective coagulation, a model is proposed and developed. The model initially considers the formation of cavitation nuclei to evaluate limit ultrasound exposure intensity realizing cavitation absence mode and then the convergence and coalescence of particles to evaluate their dispersed composition evolution during time. Evaluated exposure modes provide acceleration of coagulation up to 1.5 times during sonication in pulse mode in comparison with continuous exposure. more...

The effect of the hydrothermal method of synthesis of the initial powders using chemical reagents and illite clay as the initial components on the phase composition and structure as well as some properties of mullite-zirconium ceramic was studied. It is shown that mullite and the tetragonal modification of ZrO2 predominate in the sintered ceramic material but closed pores are also present. As the firing temperature increases and especially with the addition of illite clay the degree of sintering and therefore the compression strength increase. The elastic modulus increases with temperature difference increasing to 1000/20°C, just as with the addition of illite clay, to 35 and 95 GPa, respectively, while with 500/20 it increases to 20 and 22 GPa. more...

Results are provided for a study of the development of high-temperature mullite-zirconium ceramic with use of activated ceramic powders prepared by grinding for different times with addition of illite clay, and from pure oxide powders. It is shown that increased activity and amorphicity of ground particles considerably promotes formation of mullite phase at 1200°C, and also transition of the monoclinic modification of ZrO2 to tetragonal, particularly with an increase in firing temperature. It is proposed that as a result of rapid “freezing” the structure retains the high-temperature modification of ZrO2, having a tendency with slow ceramic cooling to transform into the monoclinic modification. more...

We study the general approach to accelerating the convergence of the most widely used solution method of Markov decision processes with the total expected discounted reward. Inspired by the monotone behavior of the contraction mappings in the feasible set of the linear programming problem equivalent to the MDP, we establish a class of operators that can be used in combination with a contraction mapping operator in the standard value iteration algorithm and its variants. We then propose two such operators, which can be easily implemented as part of the value iteration algorithm and its variants. Numerical studies show that the computational savings can be significant especially when the discount factor approaches 1 and the transition probability matrix becomes dense, in which the standard value iteration algorithm and its variants suffer from slow convergence., 32 pages, 2 figures, 2 table more...

The paper concerns numerical algorithms for solving the Beltrami equation $f_{\bar{z}}(z)=\mu(z) f_z(z)$ for a compactly supported $\mu$. First, we study an efficient algorithm that has been proposed in [P. Daripa, J. Comput. Phys., 106 (1993), pp. 355-365] and [P. Daripa and D. Mashat, Numer. Algorithms, 18 (1998), pp. 133-157] and present its rigorous justification. We then propose a different scheme for solving the Beltrami equation which has a comparable speed and accuracy, but has the virtue of easier implementation by avoiding the use of the Hilbert transform. The present paper can also be viewed as a prologue to one important application of the Beltrami equation: it provides a detailed description of the algorithm that has been used in [D. Gaidashev, Nonlinearity, 20 (1998), pp. 713-741] and [D. Gaidashev and M. Yampolsky, Experiment. Math., 16 (2007), pp. 215-226] to address an important issue in complex dynamics—conjectural universality for Siegel disks. more...

The article is devoted to development and design of the carousel-type automated line for ultrasonic welding of the article made of thermoplastic materials. Developed automated line is intended for ultrasonic ring welding of two work pieces of spherical articles from thermoplastic materials. more...

This paper considers a network consisting of~N nodes having~$rN$ servers. At each node a Poisson flow of rate $\lambda(t)$ arrives. If a particle arrives at an empty node, it leaves the system. If there are servers at the node, then a server is chosen equiprobably, takes a particle, and passes it to a random node which is chosen equiprobably. The passing time has exponential distribution with mean one. The number of servers at each of~N nodes is bounded by~m. We investigate the stability of a limit deterministic process obtained as~${N\to\infty}$. Further, we apply our results to the queueing theory with a complicated discipline of the choice of a server. more...

Markov chains are used as a formal mathematical model for sequences of elements of a text. This model is applied for authorship attribution of texts. As elements of a text, we consider sequences of letters or sequences of grammatical classes of words. It turns out that the frequencies of occurrences of letter pairs and pairs of grammatical classes in a Russian text are rather stable characteristics of an author and, apparently, they could be used in disputed authorship attribution. A comparison of results for various modifications of the method using both letters and grammatical classes is given. Experimental research involves 385 texts of 82 writers. In the Appendix, the research of D.V. Khmelev is described, where data compression algorithms are applied to authorship attribution. more...

In the article the results of the researches on efficiency definition of ultrasonic coagulation of ready nanodispersed product are presente. Developed measuring bench allowed to control changes of concentration of nanoparticles due to their agglomeration at the application of high-intensity ultrasonic vibrations. more...

The article is devoted to the development and design of automated conveyor line for ultrasonic welding of the wares made of thermoplastic materials. Produced automated line is intended for ultrasonic welding of circular seam of two workpieces of thermoplastic spherical wares. more...

The article is devoted to development of specified ultrasonic equipment for specifically drilling of fragile and very hard materials.

This paper is devoted to the development of equipment of industrial applications. The model setup that can provide various types of extinguishing foams in industrial scale. The results measure the distribution of vibration amplitude, sound pressure level of the emitting surface of the disk radiator step-variable form. more...

The article is devoted to design of promising means of nanomaterial atomization. The construction of developed ultrasonic atomizers is described and the methods of their application are recommended. more...

The article is devoted to the method of low-temperature drying of materials in the food industry based on application of the compact drier consisting of the ultrasonic vibration system with the aluminum thickness stepped-variable disk radiator. more...

The article demonstrates the results of the experiments aimed at determining the possibility to destruct fine (3 µm and less) industrial mists by acoustic vibrations of ultrasonic frequency. The experiments aimed at destruction of industrial mists were carried out in the aerosol chamber with the volume of 1.25 m3. The piezoelectric vibrating system with disk radiator was applied as a source of ultrasonic vibrations. It was shown that use of ultrasonic influence allows reducing the time of mist destruction up to by 3 times. more...

The article proposes a new method of particle coagulation with the help of ultrasonic vibrating system with the radiator in the form of disk step-variable in thickness. For practical application the design procedure of radiators of step-variable type is described. more...

The radiation heating of copper, silver, molybdenum and quartz substrates covered with oxide films in ambient gas (air, argon) is found to result in the following: (i) a non-monotonic alteration of the transmission coefficient (quartz) during amorphous—crystalline phase transitions; (ii) an absorptivity (A) increase during metal substrate diffusion into the deposited film; (iii) a periodic alteration of A due to oxidation of the substrate under the film. more...

The article is devoted to the development of cheap compact ultrasonic generator oriented for individual use.

The article is devoted to the development of ultrasonic device for destruction of subcutaneous fat as an aid during weight-reducing treatment. Developed equipment meets necessary technical requirements and now is at the stage of clinical trials. more...

In this paper the tendencies, which let to create and apply piezoelectric transducers with enlarged radiation surface in order to increase the efficiency of ultrasonic technological devices, are analyzed. The article demonstrates some practical examples of using of designed systems including the device for wastewater treatment. more...

Results of researches of influence of acoustical contacts between exchangeable operating tool and electro-acoustical transducer on mechanical and electrical characteristics of oscillatory system are presented in this article. Measured amplitude-frequency and phase-frequency dependence of oscillatory system with various types of operating tools are shown. Analyze of measured dependences is made. Searching of criteria of quality of acoustical contact is made. Usage of founded criteria allows preventing a damaging of ultrasonic technological device or its operation in the ineffective mode. more...

This article is devoted to the development and investigation of ultrasonic equipment used for reduction of friction coefficient during the moving of free-flowing and hard filling compounds through tubular members. more...

In article the basic operating modes of ultrasonic electronic generators, algorithms and ways of their realization are described.