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Our study, aimed at assessing the impact exerted by the inclusion to a low-efficiency cyclone of an additional "bypass" pipe connecting the cyclone's inlet branch pipe and the exhaust pipe, has been established the mechanisms to improve the energy efficiency and the process of purifying air from dust. It has been proven that the increase in the degree of purification is explained by a decrease in the radial flow rate under the exhaust pipe of the cyclone. The decrease in hydraulic resistance is due to a decrease in the flow rate along the inlet branch pipe when the air is fed separately to the body through the inlet branch pipe and the "bypass" pipe. Our experimental study has confirmed that when the cyclone design is supplemented with a "bypass" pipe in the most dangerous area of the cyclone in terms of dust release (under the exhaust pipe), the radial rate of the gas flow that negatively affects purification is reduced. This leads to an increase in the overall degree of purification from dust. The result of analytical calculations and computer simulation by the SolidWorks-2009 software were experimentally confirmed when investigating the effectiveness of dust capture from powdered skimmed milk in an industrial cyclone (a 630-mm diameter) with a "bypass" pipe. Such a cyclone is installed in the system of pneumatical transportation at the spray dryer "CT-500" at Ichnya Milk Powder and Butter Plant (Ukraine). Specifically, it has been established that the removal of dust is reduced almost twice, hydraulic resistance ‒ by 15%, and the energy efficiency of the cyclone with a "bypass" pipe increases by 2.43times. Thus, there is a reason to argue about the possibility of significant energy efficiency improvement of the cyclone with a "bypass" pipe. This makes it possible to assess the energy efficiency of the cyclone in the early stages of design

The GMOS (Global Mercury Observation System) project has the overall goal to develop a coordinated observing system to monitor mercury on a global scale. Here we present the long-term (2011–2020) air mercury monitoring data obtained at the Listvyanka station located at a shore of Lake Baikal, Siberia. The long-term monitoring shows obvious seasonal variation of the background mercury concentration in air, which increases in the cold and decreases in the warm season. The short-term anomalies are associated with the wind carrying the air from the industrial areas where several big coal-fired power plants are located. A positive correlation between the mercury, SO2 and NO2 concentrations is observed both in the short-term variations and in the monthly average concentrations. The analysis of forward and backward trajectories obtained with the HYSPLIT model demonstrates revealing of the mercury emissions sources. During the cruise of 2018, the continuous air mercury survey over Lake Baikal covered 1800 km. The average mercury concentration over Baikal is notably less in comparison with the average value obtained at the onshore Listvyanka station during the same days of the cruise. That can lead to the conclusion that Baikal is a significant sink of the atmospheric mercury.

This chapter provides recommendations for the implementation of the virtual labs considered in Chapter 1. This chapter is to be used when encountering difficulties in Chapter 1. The instructions contain the necessary reference material that is needed to complete the tasks. For each lab from the Chapter 1, there are guidelines and recommendations on how to construct the diagrams of component models and to perform the model simulation. In addition, example answers to the tasks set in each lab are provided.

Shungite is a mineraloid consisting of up to 99 % of carbon. The first deposit was found near Shunga village (Karelia, Russia) within the Paleoproterozoic host rocks. Karelian shungites represent the greatest accumulations of carbon with reserves of up to one billion ton. Shungite matter is considered as a specific allotrope of carbon having complex globular supramolecular structure with the globules size of 5-10 nm and including 0.0001 – 0.001 % of natural fullerenes. There are two opposite opinions on the shungite origin: the deep metamorphism of the organic-rich sedimentary rocks and the pyrolysis of the mantle methane jets. In its properties, shungite occupies an intermediate position between anthracite and graphite. Mercury in coals is quite fairly studied: according to hundreds thousand analyses, the average mercury content varies in a range from ppb to few hundred ppm with a world average of 100 ppb. In contrast to coal, so far almost no data on mercury in shungites are available.Zeeman AAS was used for determination of the total mercury concentration in shungites from Karelian shungite deposits. Surprisingly high concentration up to 12,000 ppb with an average of 2200 and median of 1100 ppb was found in all samples. That is much higher than world average value and even three times higher as compared with the mercury concentration in studied coals of the Donetsk basin (450 ppb) located within the mercury belt. The thermoscanning technique revealed a high-temperature form of mercury in shungites releasing at a temperature above 650 OC and comprising 40-45% of the total mercury. That drastically differs from the thermospectra of anthracite with the main portion of mercury being released at a temperature below 480 OC. The loss of mass for anthracite and shungite during heating to 900 OC is practically identical, whereas the loss of mercury from anthracite is much faster. As both substances consist mainly of carbon, the difference in mercury binding energy can be explained by a specific globular structure of the shungite matrix. Additional experiments on the shungite exposure to mercury in the liquid and gaseous phases showed the increased mercury release at a low temperature and no increase in the high temperature species. The occurrence of a significant portion of the uncommon high temperature species suggests that this mercury can be transported with the mantle methane jets and captured inside the stable carbon globules of the shungite.Preliminary assessment of the mercury resources only for three proven deposits (54 million ton of shungite, Filippov, 2002) gives the value of 55 t Hg. Shungite is widely used in ferrous metallurgy, for water purification, in cosmetology, etc. Shungites have to be considered as a potential source of the mercury emissions in metallurgy. Also, shungite mercury behavior in other industrial, ecological, medical, and cosmetology applications should be studied.

This chapter gives a general idea of the fundamental principles that underlie any mathematical model such as conservation laws or variational principles. On these principles, the simplest models are built. These models are used as the basis for building more complex hierarchical models. The application of fundamental principles is illustrated with examples such as a harmonic oscillator. The reader gets acquainted with the hierarchical principle of building models from simple to complex. In more complex models, the external disturbing force, the forces of dry and viscous friction, or the physical nonlinearity are taken into account. Examples of using non-inertial reference systems are also provided.

In this chapter, the reader is invited to study methods for solving more complex problems. These are multi-component and hybrid systems. It is proposed to use two approaches: directly developing computer models on the Modelica language and using component modeling technologies with the application of the standard Modelica libraries. The modeling of mechanical oscillatory systems with several degrees of freedom is considered. The following illustrative examples of such dynamic models are given: the relative motion of two bodies, complex oscillatory mechanical systems of dampers and springs, and coupled and double mathematical pendulums.

This chapter is devoted to building hierarchical component models and creating custom libraries in the Wolfram SystemModeler. The reader gets acquainted with the concepts of blocks and connections. The concepts of oriented and non-oriented connections between blocks are introduced. Mathematically these connections include algebraic and differential equations which describe behavior and interactions of system objects. The following illustrative examples of such models are demonstrated: model of draining of a tank (on the Modelica language); problem of heating a liquid mixture with the help of a PID controller (by using the custom components); inverted pendulum problem.

This chapter describes Wolfram SystemModeler (WSM), an interactive graphical modeling and simulation environment. The WSM is intended for computer simulation of complex multi-domain physical and engineering systems and processes based on the Modelica language. It allows to simulate the developed models and provides a wide range of tools for analyzing the results of the simulation. The reader gets acquainted with the basics of writing program code with the use of the object-oriented language Modelica. In addition, the basics of working in the Model Center to create a component model using the Modelica standard library are demonstrated. The principles of creating custom components as well as the rules for performing a computational experiment in the Simulation Center are described in detail. The chapter contains a large number of simple and useful examples.

The mercury concentration in coal varies in a wide range with the world average (the Clarke value) of 100 ppb. Mercury in coal can be represented by various forms having different matrix binding energy that govern different properties and behavior both in geochemical cycling and in technological processing. The technique of gradual heating (thermoscannig) of samples based on standard available equipment was developed to reveal and study the dynamic behavior of mercury release from coals. Analyses of coals of different types from deposits in Russia, Ukraine, and South Africa revealed the presence of various mercury thermospecies, part of which can be attributed to absorbed elemental mercury and mercury bound to pyrites. Microprobe analysis exhibited points of mercury accumulation up to tenths of percent by weight within coal organic matrix and mineral inclusions. The thermoscanning technique gives additional information about mercury speciation in coal for better understanding of mercury geochemistry in fossil fuels and also for enhancement of the coal pre-treatment technology before combustion or gasification to reduce mercury emission to environment.

The paper describes the modeling, development and testing results of a multi-agent control system for a group of ground-based robots. The developed model of collective behavior was verified in the Matlab system, then transferred to the ROS framework and tested in the virtual Gazebo environment. Such a development path allowed us to obtain a workable code at the computer simulation stage and then use it to ensure the functioning of a group of autonomous ground-based robots in natural conditions. The paper describes all the main stages of the project: development of a mathematical model of the multi-agent control system, implementation in ROS system using Python language and verification by control of real robot group (group of eduMIP robots). Comparison of the results of computer simulation and the physical experiments made it possible to conclude that they are sufficiently consistent, which in turn confirms the correctness of the constructed group control model. Thus, within the framework of the SMTU project, the task of developing models and group control algorithms for a simple multi-agent system has been solved. The purpose of the next stage of work is the adaptation and development of proven models and algorithms for the control system of a group of underwater robots.

Results of the work carried out by Saint-Petersburg State Marine Technical University in the framework of the project, connected with complex researches in maintenance of creation of a multi-agent sensory-communication network based on marine robotic platforms (MRP), are presented. In the context of the mentioned works, creation and testing of communication protocol for µAUVs with hydroacoustic modems is proposed. The article describes steps of protocol creation: from mission planning to modem control and modeling with digital imitation model testing (Solving the task of monitoring the seabed area). Within the framework of the concept of a “budget”, limited serial product, functional systems/modules of µAUV are worked out, taking into account the availability of equipment and components (concerning required technical characteristics and their cost). For the selected external appearance and design dimensions of the device, the simulation of hydrodynamic, signal power and energy characteristics were performed. Within the framework of the project, a software and hardware architecture of the information system of the vehicle was developed, as well as a model of interaction between the µAUV, the wave glider and control center. The work results in proposal and testing of µAUVs communication through the water. Simulation results of implementing mission by a group of developed µAUVs can be modeled by ground robots with some software limitations. Based on the results, ways for further work on the subjects are being determined.

This paper examines the results of work undertaken by Saint-Petersburg State Marine Technical University (SMTU) as part of a project involving research into the creation of a multi-agent sensory network based on marine robotic platforms (MRP). In the context of the works mentioned, creation of a micro autonomous underwater vehicle (µAUV) is considered. High maneuverability, the availability of a modular architecture and functions of the group use are required for the developed µAUV. The article describes steps of the vehicle creation: concept development, modeling, design, construction, simulation of the implementation of various vehicle group mission scenarios (Solving the task of monitoring the seabed area). A standard chassis which allows the assembly of all systems, units and mechanisms of the device in minimum dimensions, has been established. Within the project, a software and hardware architecture of the information system of the vehicle was developed, as well as a model of interaction between the µAUV, the wave glider and control center. The work results in two full-scale experimental samples of µAUV capable of working in a group together with the wave gliders, performing the functions of a repeater signal through the environmental boundary, and simulation results of implementing the mission by a group of developed µAUV.

The concept, general provisions and some results of the research & education initiative of Saint-Petersburg State Marine Technical University (SMTU) «Marine Robotics: Education through Research» (MRER) are considered in the paper. The directions of research conducted at SMTU in the field of marine robotics, as well as up-to-date technologies of training of future engineers specializing in a certain area are represented. Some work results of a student team, developing a small unmanned remotely operated vehicle (ROV) are presented to exemplify the «through project study» approach. One of the innovative solutions validated on this ROV is implementation of hydroacoustic modem based on polyphase filters and employed for positioning and communication with other AUV.

A general spectral boundary value problems framework is utilized to restate Poincare, Hilbert, and Riemann problems for harmonic and analytic functions in an abstract operator-theoretic setting.

We construct the symmetric functional model of an arbitrary closed operator with non-empty resolvent set acting on a separable Hilbert space. The construction is based on the explicit form of the Sz.-Nagy-Foias model of a closed dissipative operator, the Potapov-Ginzburg transform of characteristic functions, and certain resolvent identities. All considerations are carried out under minimal assumptions, and obtained results are directly applicable to problems typically arising in mathematical physics. Explicit formulae for all the objects participating in the model construction are provided.

The paper defines the Weyl–Titchmarsh function for an abstract boundary value problem and shows that it coincides with the transfer function of some explicitly described linear boundary control system. On the ground of obtained results we explore interplay among boundary value problems, operator colligations, and the linear systems theory that suggests an approach to the study of boundary value problems based on the open systems theory founded in works of M. S. Livsic. Examples of boundary value problems for partial differential equations and calculations of their Weyl–Titchmarsh functions are offered as illustration. In particular, we give an independent derivation of the Weyl–Titchmarsh function for the three dimensional Schrodinger operator introduced by W.O. Amrein and D.B. Pearson. Relationships to the Schrodinger operator with singular potential supported by the unit sphere are clarified and other possible applications of the developed approach in mathematical physics are noted.

A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions ((196)Hg, (198)Hg, (202)Hg, (204)Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope (204)Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m(3) for benzene) level, the interference from SO2, NO2, O3, H2S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m(3) at 1 s averaging and 0.1 mg/m(3) at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified.

Zeeman mercury spectrometer RA-915+ is suitable for the direct determination (without the preconcentration step in the absorption trap) of mercury concentrations in various samples, such as air, water, soil, food, coal, oil and so on with background levels detection limits. The mercury concentrations were determined by the same RA-915+ spectrometer using different attachments to convert bound mercury to its atomic form. To determine mercury concentrations in samples with complex matrix without pre-treatment (whole blood, hair, crude oil, vegetation, food), a two-chamber pyrolytic atomiser was developed. Its design allows to separate the processes of evaporation and dissociation of mercury compounds as well as to simplify the matrix components in the gaseous phase in real time. Results of analyses of samples with simple and complex matrices are shown in the paper.

It is the objective of this survey to review research and development results of flapping-wing propulsors and of vehicles equipped with them. Given the complex and multi-disciplinary character of the problem, a wide range of questions is considered in order to provide a general idea of the state-of-the-art. The main attention is directed at the aerohydrodynamics of flapping-wing propulsors. The major relevant mathematical models and the corresponding numerical results are presented together with the experimental data obtained up to the present time. Also, the physical and the design factors are discussed, which affect the aerohydrodynamic characteristics of flapping wings and that therefore have to be accounted for in the modern mathematical models. Experimental data and numerical modeling results are compared to determine domains of validity of the latter for the aerohydrodynamic design of full-scale air and marine vehicles. Also, existing engineering solutions for vehicles with flapping-wing propulsors are presented and prospective directions for future investigations are outlined.

A new rapid technique is presented for determination of the dose of mercury inhaled; it is based on direct measurement of the concentration of mercury in exhaled air by use of a Zeeman mercury spectrometer RA-915+. It has been demonstrated experimentally that the dose received during short-term exposure to mercury vapor is determined more reliably by this method rather than by conventional techniques based on measurement of the mercury content in blood or urine.

This paper offers the functional model of a class of non-selfadjoint extensions of a symmetric operator with equal deficiency indices. The explicit form of dilation of a dissipative extension is offered and the Sz.-Nagy-Foias model as developed by B. Pavlov is constructed. A variant of functional model for a non-selfadjoint non-dissipative extension is formulated. We illustrate the theory by two examples: singular perturbations of the Laplace operator in L 2(ℝ3) by a finite number of point interactions, and the Schrodinger operator on the half-axis (0, ∞) in the Weyl limit circle case at infinity.

Direct on-line measurements of the mercury (Hg) content in natural gases by a newly developed Zeeman atomic absorption spectrometer RA-915+ have revealed a short-term variability of the Hg concentration, which has not earlier been known. The significant variability of the mercury concentration in a hydrocarbon gas was found in all of the gas wells studied. The variation magnitudes range from 10 to 80% of the average mercury content in the gas. The fluctuations have regular components with periods from few minutes to several hours and can be represented as a set of harmonics with different spectral intensity and stability in time. The most stable harmonics are characterised by intermediate frequencies with periods of 0.3-2.5 h. These 'basic' frequencies are characteristic of individual gas wells even within a single productive horizon. The remarkable features of these harmonics are the multiplicity of their periods and good agreement with phases of the Earth's own oscillations. A relatively low-frequency oscillation with a period of 25 h corresponds to a lunar tidal cycle. An oscillatory mechanism of the adsorption-desorption of mercury in a porous gas-bearing medium is assumed to be responsible for these effects.

The main regularities of location of mercury-bearing gas and oil deposits are discussed. The mantle source of mercury in these deposits is debated. Correlative relations of mercury with other elements are described. Some evaluation examples of reserves of mercury in gas and oil deposits with high mercury content are given. Examples of regional and local prognosis of mercury-bearing deposits are shown.