bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystallization of metals in the ultrasonic field
Authors: Danilov Pavel , Kudryashova Olga , Khmeleva Marina
Published: December 2018

In the manuscript process of crystallization of metals at ultrasonic influence is considered. The known models of crystallization under the influence of ultrasound are investigated. By means of calculations influence of parameters of ultrasonic influence and characteristics of crystals of metal on the received structure of alloy is established. The corresponding mathematical model of ultrasonic crushing of particles and their agglomerates in metal fusion is offered. It is determined the threshold mode of ultrasonic influence on fusion at which almost monodisperse distribution of particles by the sizes is reached.
The ultrasound effect on the morphological properties of hydroxyapatite
Authors: Chuprunov Konstantin , Kolesnikov Eugenii , Ilinykh Igor , Yudin Andrey , Leybo Denis , Karunakaran Gopalu
Published: December 2018

The present study considers the morphological and dispersity characteristics of hydroxyapatite (HAp) samples synthesised through the ultrasound-assisted hydrothermal method with additional pressure treatment. The samples were analyzed by the X – Ray diffraction, scanning electron microscopy, low-temperature nitrogen adsorption. The ultrasound effect on the HAp morphologiy and dispersity was studied. The pressure assisted ultrasonic treatment made possible obtaining HAp samples with different morphology from rods and flakes to particles with irregular shape close to spherical. Also pressure assisted ultrasonic treatment able to increase the porosity of HAp materials.
Antibacterial activity of zinc oxide nanoparticles obtained by pulsed laser ablation in water and air
Authors: Goncharova Daria , Gavrilenko Ekaterina , Nemoykina Anna , Svetlichnyi Valery
Published: December 2018

The paper studies physicochemical and antibacterial properties of ZnO nanoparticles obtained by pulsed laser ablation in water and air. Their composition and structure were studied by X-ray diffraction, transmission and scanning electron microscopy. Antibacterial activity of the nanoparticles was examined by its affection on Gram-positive Staphylococcus aureus (S.aureus). The dependence of nanoparticles’ physical and chemical antibacterial properties on the conditions of the ablation was shown. The model materials for the antibacterial bandage were made of cotton, filter paper and biodegradable polymer scaffolds (poly-l-lactide acid), and then they were coated with the obtained ZnO nanoparticles. The model bandage materials were examined by the scanning electron microscopy method and their antibacterial activity (ISO 20743:2013) was determined. High activity of all the samples against S.aureus was proved.
Structure and phase composition of material based on vanadium alloy V-4.9Ti-4.8Cr and ferrite steel 17Cr-12Ni-Fe
Authors: Dement Taras , Kurzina Irina , Kalashnikov Mark , Popova Natalia , Karakchieva Natalia
Published: December 2018

Three-layer materials consisting of the V-4.9Ti-4.8Cr/ferrite steel 17Cr-12Ni-Fe /V-4.9Ti-4.8Cr were obtained in the paper. Phase composition and microstructure of the transition zone of the three-layer material of vanadium alloy V-4.9Ti-4.8Cr and ferrite steel 17Cr-12Ni-Fe were considered. The use of the method of direct laser growing allowed obtaining a three-layer material with qualitative interconnection of layers, as well as decreasing a multistage nature of deformation and thermal operations used when obtaining a three-layer material in earlier works. Additional thermal treatment of a three-layer alloy led to growth of matrix grains up to 100 μm of the vanadium alloy. A uniform distribution of main elements V, Ti, Cr was observed in the transition zone both before and after annealing. A zone of interdiffusion of the metals amounted to 250-350 μm.
Influence of scandium fluoride on the structure and phase composition of Al-Si alloy
Authors: Khrustalev Anton , Vorozhtsov Alexander , Kazantseva Lyudmila , Promakhov Vladimir , Kalashnikov Mark , Eskin Dmitriy , Kurzina Irina
Published: December 2018

The composition and the microstructure of А356 alloy, obtained by means of addition of scandium fluoride into the melt, were studied. The influence of the amount of the introduced component on the material structure was researched.
Investigation of structure, mechanical properties and crystallization of aluminum alloys containing aluminum oxide nanoparticles
Authors: Valikhov Vladimir , Kahidze Nikolay , Khrustalyov Anton , Zhukov Ilya , Vorozhtsov Alexander
Published: December 2018

A357 and 6082 aluminum alloys strengthened by aluminum nitride nanoparticles were obtained. The process of crystallization of the A357-0.5 wt% Al2O3and 6082-0.5 wt% Al2O3alloys was studied under conditions of varying the cooling rate. The A357 and 6082 aluminum alloy structure and hardness were analyzed for the Al2O3content from 0 to 1 wt%.
Manufacturing sound-absorbing structures by 3d-printing
Authors: Pisarev Pavel , Anoshkin Alexander , Merzliakova Natalya
Published: December 2018

In this research we developed the methods and technologies for manufacturing sound-absorbing structures (SAS) samples using Dimension SST 1200 and Envisiontec Perfactory XEDE units. While testing the technique, the shortcomings of both units were identified. To eliminate the identified shortcomings, we formulated some recommendations and adjusted the main stages of manufacturing SAS with the application of these methods. Experimental acoustic studies of the produced reference samples of the SAS on an interferometer with normal incidence of waves were carried out. Acoustic tests of samples of SAS manufactured with consideration of the developed technological solutions showed good sustainability of the obtained results, we revealed strong correlation with the samples from polymer composite materials manufactured using standard plant technologies.
Stiffness of 316L stainless steel support structures proposed for the SLM process
Authors: Hajnyš Jiří , Pagáč Marek , Zlámal Tomáš , Petrů Jana , Kousal Lukáš
Published: December 2018

The subject of the article is to compare and evaluate the stiffness of the proposed structures relative to the section of the individual rods. The study is applicable to the additive technology of metal production by the 316L (1.4404) by SLM method. In the SLM process the design supports serves as the transporter of the heat generated in the melting bath to the substrate, the secondary function of the structures is for support the powder layer. The article focuses on the supportive function and weight ratio. A total of 4 structures were designed in iteration with three different rod diameters. During construction, the suitability of structures for the SLM method was determined and then the samples were subjected to a mechanical tensile test and the mechanical properties evaluated. In conclusion the most appropriate structure for the supportive function was identified.
The contribution to the modal analysis of the control system
Authors: Sapietová Alžbeta , Chovanculiak Filip , Dekýš Vladimír , Gajdoš Lukáš
Published: December 2018

This article deals with the analysis of the suitability of using selected solution methodologies while taking into account the different degrees of simplification used. Three ways of determining the first frequency of the mechanism were presented on the lever mechanism of the control circuit. The solution is carried out analytically, then via a calculation model in the program on the dynamics of systems elements MSC ADAMS, and lastly, an experimental measurement was carried out.
Measurement of industrial robot pose repeatability
Authors: Kuric Ivan , Tlach Vladimír , Ságová Zuzana , Císar Miroslav , Gritsuk Igor
Published: December 2018

The article deals with measurement of pose repeatability of industrial robot Fanuc LR Mate 200iC. Laser interferometer Renishaw XL-80 and digital indicator Mitutoyo Absolute Digimatic ID-F are used for the measurement. The measurement methodology is based on so-called ISO cube placed in the most used part of robot workspace. Individual steps of the solution, the analysis of measurement data and results are presented in the article.
Nanocomposite coatings in polymeric matrices and their effect on friction coefficient
Authors: Novotný Jan , Lysoňková Irena , Sapieta Milan
Published: December 2018

This paper deals with possibilities of production of new nanocomposite coatings in polymer matrix on aluminium alloys, namely the formation of a composite coating in a polymer matrix on an aluminium alloy. It is a PMMA coating (polymethylmethacrylate) with the addition of TiO2 particles. Working with these particles requires not only safety but also a suitable preparation process to obtain particles of suitable size, their subsequent homogeneous distribution in the coating (particles of this size are influenced by electro statically attractive forces and have a strong tendency to aggravate).The aim is to determine if the coatings will affect the surface‘s condition and its properties. The focus of the work is on selecting of the appropriate preparation of sample technology, examining the particle distribution in the coating and the effect of the coating on the coefficient of shear friction. Consequently, what can be achieved is the coefficient of shear friction of the surface of the coated part compared to the uncoated surface (at different particle concentrations in the spin) and the distribution of TiO2 particles on the surface of the sample.
Application of artificial intelligence principles in mechanical engineering
Authors: Zajačko Ivan , Gál Tomáš , Ságová Zuzana , Mateichyk Vasyl , Wiecek Dariusz
Published: December 2018

The article deals with methods of Artificial Intelligence and their utilisation in technical diagnostics. Special meaning will be given on methods such as Deep learning. The deep learning method seems to be a very good candidate for defect detection and pattern recognition. The method was applied for technical diagnostic in automotive factory and the problem will be described in the paper.
The evaluation of the surface quality after laser cutting
Authors: Zlámal Tomáš , Malotová Šárka , Petrů Jana , Brytan Zbigniew , Musil Václav
Published: December 2018

The contribution deals with the evaluation of the surface quality after laser cutting and determination of the influence individual input laser parameters at the whole process. There were selected samples for experiment made from S235JR material with the thickness 10 mm and 15 mm. There was set up values of process parameters, such as laser power, focal spot position, cutting speed and shield gas pressure. The final surface quality was measured and evaluated on the basis of the selected surface roughness parameters and material ratio. The surface quality was evaluated from point of view of defects emerging after thermal splitting according to standard ČSN EN ISO 17 658.
Simulation of spark ignition engine performance working on biogas hydrogen mixture
Authors: Kriaučiūnas Donatas , Pukalskas Saugirdas , Rimkus Alfredas
Published: December 2018

Numerical simulations of Nissan Qashqai HR16DE engine with increased compression ratio from 10,7:1 to 13,5:1 was carried out using AVL BOOST software. Modelled engine work cycles while engine works with biogas (BG) and hydrogen (H2) mixtures. For biogas used mixture of 35 % carbon dioxide (CO2) and 65 % methane (CH4). Three mixtures of biogas with added 5 %, 10 % and 15 % H2 was made. The simulation of engine work cycles was performed at fully opened throttle and changing engine crankshaft rotation speeds: ne1 = 1500, ne2 = 3000, ne3 = 4500, ne4 = 6000 rpm. Simulation results demonstrated what adding hydrogen to biogas increase in-cylinder temperature and nitrogen oxides (NOx) concentration because of higher mixtures lower heating values (LHV) and better combustion process. Other emissions of carbon monoxide (CO) and hydrocarbons (HC) decreased while adding hydrogen due to the fact that hydrogen is carbon-free fuel.
Piston kinematics of a combustion engine with unconventional crank mechanism
Authors: Kukuča Pavol , Barta Dalibor , Dižo Ján , Caban Jacek
Published: December 2018

The article deals with a theoretical solution of kinematic variables describing the movement of a combustion engine piston with unconventional mechanism FIK protected by patents No. 283742 and No. 283743 [1]. The course of the path, the velocity, and the acceleration were calculated to assess the dynamic properties of the unconventional mechanism, which transform the piston linear movement to rotational movement by using a swinging board, a baseboard and a crankshaft.
To Calculation of Rectangular Plates on Periodic Oscillations
Authors: Abdikarimov Rustamkhan , Khodzhaev Dadakhan , Vatin Nikolay
Published: December 2018

Geometrically nonlinear mathematical model of the problem of parametric oscillations of a viscoelastic orthotropic plate of variable thickness is developed using the classical Kirchhoff-Love hypothesis. The technique of the nonlinear problem solution by applying the Bubnov-Galerkin method at polynomial approximation of displacements (and deflection) and a numerical method that uses quadrature formula are proposed. The Koltunov-Rzhanitsyn kernel with three different rheological parameters is chosen as a weakly singular kernel. Parametric oscillations of viscoelastic orthotropic plates of variable thickness under the effect of an external load are investigated. The effect on the domain of dynamic instability of geometric nonlinearity, viscoelastic properties of material, as well as other physical-mechanical and geometric parameters and factors are taken into account. The results obtained are in good agreement with the results and data of other authors.
Ground improvement using an expandable polyurethane resin
Authors: Sabri Mohanad , Bugrov Aleksandr , Panov Stanislav , Davidenko Viacheslav
Published: December 2018

The paper describes an experiment conducted to study the effect of injection an expandablepolyurethane resin on the stabilization, settlement reduction and increasing the bearing capacity of the foundation’s soil. The experiment was carried out in sandy soil, and different types of soil investigations were carried out to investigate the effect of the resin on the soil properties beneath a concrete foundation. Results of Plate load test PLT and dynamic cone penetration test DCPT before and after the injection of the expandable resin are demonstrated and discussed in this paper.
Strengthening the historical constructions made of limestone by treating with silicic acid based material
Authors: Sabri Mohanad , Korneeva Elena
Published: December 2018

The paper a comparative study of limestones treated with the composition Oxal NK100 for increasing the durability of the limestones in historical buildings and the other limestones without any additives to investigate the effect of the composition Oxal Nk100 on the durability of the investigated stones. Results of frost resistant test and compressive test of different samples are included and analyzed . Indicators charts and diagrams are given included and explained.
The water absorption of Crimean limestone treated with silicic acid based material
Authors: Korneeva Elena , Sabri Sabri Mohanad Muayad
Published: December 2018

The paper describes strengthening historical buildings made of limestones rocks located in the Republic of Crimea. The stones were treated with the chemical compound Oxal NK100 for filling a porous material reducing water absorption and strengthening the treated stones. The stones with additives was tested and the results were compared to natural limestones (reference samples) which not treated with any chemicals compounds. All samples are extracted in-site from an actual historical construction located in the mentioned Republic. The effect of the chemical composition Oxal NK100 on the water absorption of the investigated stones is illustrated and incorporated. The comparison data of the index graphs before and after the addition of the chemical composition are given and described.
The fire resistant ceiling construction in a hydrocarbon fire
Authors: Gravit Marina , Golub Elena
Published: December 2018

Fire protection of building structures under the hydrocarbon fire is becoming more relevant, especially in the design and construction of oil and gas and chemical complex facilities, including offshore fixed platforms, liquefied natural gas production and storage facilities and other objects of the fuel and energy complex. The development dynamics of such a fire requires a different approach to testing the structures in order to determine the fire resistance limit. The fire resistance tests of a steel horizontal structure with a fire resistance suspended ceiling of PROMATECT-T plates were carried out under the condition of creating a hydrocarbon temperature combustion regime. A detailed description of the tested ceiling design is given. It is shown that at the time of the end of the fire action, the limit state due to the loss of load capacity (R) and loss of integrity (E) was not recorded when the test reached 120 minutes.
Fine-grained concrete with combined reinforcement by different types of fibers
Authors: Klyuev Sergey , Klyuev Alexander , Vatin Nikolai
Published: December 2018

The article deals with the application of combined reinforcement of fi-ne-grained concrete with steel wave and polypropylene fibers. High-density packaging of the mixture components was used to improve the strength and deformation characteristics. In order to reduce the cost of fibre concrete, composite binders were developed. Rational selection of filler and the use of a steel wave fiber gave the opportunity to get the fibre concrete with tensile compressive strength – 84.8 MPa, the tensile strength in bending – 19.8 MPa on technogenic sands of the Kursk Magnetic Anomaly. With combined reinforcement by steel and polypropylene fiber on technogenic sands of the Kursk magnetic anomaly fibre concrete with a tensile compressive strength – 82.8 MPa, in bending – 19.1 MPa was developed. With the same strength charac-teristics the developed mixture of fibre concrete based on combined re-inforcement due to reducing the amount of steel fiber at cost is lower by 25% compared to the composition on steel fiber and the same com-posite binder.
Composite material based on the polyethylene terephthalate polymer and modified fly ash filler
Authors: Zaichenko Nikolai , Nefedov Vladislav
Published: December 2018

The possibility of filling the recycled polyethylene terephthalate (rPET) with fly ash was studied to make a polymer composite material (PCM). It is shown that high adhesion between polymeric matrix and mineral filler is the key parameter to produce high performance PCM. For this purpose the acid-basic interaction as well as the thermodynamic work of adhesion between components of PCM were calculated. The technique of modifying fly ash filler with 5% concentration solution of sulfuric acid to increase acid-basic interaction has been elaborated. The resulting behavioral patterns are listed and compared to those of composites containing untreated fly ash particles.
Research of professional suitability in construction by the noise factor
Authors: Kireeva Lilia , Kaverzneva Tatiana , Tarkhov Dmitriy , Belina Natalia
Published: December 2018

The field of construction is one of the most traumatic areas of human activity. Various methods are used to reduce injuries and increase the safety level at construction sites, which do not allow to reduce the level of injury risk. In other industries characterized by heightened danger, the risk management methodology based on the “human factor” management is gaining popularity. By attracting the most relevant workers, we can compensate for a significant portion of the risks. The authors propose the use this concept in the field of construction. In this paper, a study of professional fitness in construction during work requiring an increased level of attention and reaction under the influence of noise factor was conducted. For this purpose, testing was per-formed to identify the dependencies between the external effects of noise and attention indicators. During the testing the subjects demonstrated various concentration abilities. We concluded that, using this methodology, it is possible to select “successfully fit” personnel to perform specific tasks in construction, in order to increase the level of safety.
Thermal - insulation material for frame panels with an internal non-metallic layer
Authors: Aksenov Boris , Stepanov Oleg , Stefurak Ludmila
Published: December 2018

The foam plastic capable to work in frame panels as a thermal - insulation and facing and decorative material can be only of composite type. We have developed a new type of composite foam plastic, its density increases from center to surfaces. The article presents the composition of new material, the technology of its production, as well as the mathematical model of the mechanism of formation of strong crusts at its surfaces. Microscopic analysis of the composite showed that the density of crust is more than 200kg / m3, the density of the foam plastic in its middle part is 80kg / m3. The limit of strength at punching it by the rod diameter 0.01 m reaches 3.5MPa. The material is used for the manufacture of roofing panels, frame panels with an internal non-metallic layer.
Temperature action in analysis of thermal stressed state of massive concrete and reinforced concrete structures
Authors: Makeeva Aleksandra , Amelina Aleksandra , Semenov Kirill , Barabanshchikov Yuriy
Published: December 2018

The work is dedicated to research of the thermal stresses state of massive concrete and reinforced concrete structures in construction period. The article examines the results of the analysis of the thermal stress state, which occurs in massive concrete ground slab with thickness of 1 m. The study was conducted with using analytical models, which include the factor of diurnal temperature range in comparison with simplified methods. Authors established that solving the problem of thermal stressed state of the massive foundation slabs in the building period without taking into account the influence temperature changing during the month might not cause to significant deviation of the real diagram of the thermal stresses and elongation deformations in the structures body: error is less than 0.5%.
The effect of modification of binders on technological and operational properties of composite construction materials
Authors: Zakrevskaya Lyubov , Handelsman Igor , Provatorova Galina
Published: December 2018

The object of the study includes modified road bitumen and geotextile materials, for the synthesis of which recycled PET and CNT were used. The production of new materials is caused by the need to improve their technical characteristics, which, in the end, should have a positive impact on the properties of composites based on them. The main method of research is an experiment. During the experiment, a grid of compositions of new materials and laboratory technology for their production were developed, their basic properties were studied. According to the results of the study of the basic properties of new materials there is an improvement of their basic properties up to 10% compared to the original ones.
On accuracy estimation of ultrasonic thermometry technique with heated wire method
Authors: Smirnov Evgeny , Yukhnev Andrey , Gataulin Yakov , Sinitsyna Daria , Berkovich Alexander , Tarkhov Dmitriy
Published: December 2018

A test object with a heated wire introduced into a tissue-mimicking material and a method for determining the coefficient of ultrasonic thermal strain are described. The accuracy of the developed ultrasonic thermometry method is estimated using data of thermistor sensor measurements of time-dependent axisymmetric temperature field around the heated wire.
Reduction of power consumption during arc welding operation
Authors: Sakhno Liudmila , Sakhno Olga , Boronin Vitaliy , Kochetkova Elena , Hao Chen
Published: December 2018

The work is devoted to energy saving during arc manual welding operations. Power sources for arc manual welding are rectifiers with slow or steeply falling current-voltage characteristics. The paper considers two ways of energy saving during arc welding operations. The first way is to increase the efficiency of welding by replacing the ballast rheostat with a special electronic device that regulates the welding current instead of the ballast rheostat. The second way is to increase the efficiency of the welding equipment by replacing a traditional one-bridge rectifier with the two-bridge economical rectifier. An approximate calculation of the annual economic effect from the replacement of a ballast rheostat by the electronic regulating device is given on the example of welding operations in a typical assembly shop.
Management of energy efficient measures by buildings’ thermorenovation
Authors: Zemitis Jurgis , Terekh Maxim
Published: December 2018

The system of integral indexes for estimation of economic efficiency of warm isolations of dwelling and civil buildings is resulted in the article. For the management by energysavings measures during realization of investment projects in the conditions of financial limitations effectively to apply economic-mathematical methods. Application of method of the dynamic programming at the choice of effective measures on the heatcover of barriering constructions of buildings allows to get the mixed optimum strategy of the use of the limited investments.
SOFC power plant with circulating fluidized bed gasifier
Authors: Volkova Yulia V , Munts Vladimir , Choynzonov Dmitry B , Plotnikov Nikita S
Published: December 2018

Coal is used all over the world to meet the energy needs of industry and housing and communal services. The main requirements of coal using are environmental safety and efficiency. Increasing these parameters can be realized with the combination of a gasifier and fuel cells. The paper includes a variant of the thermal scheme of the power plant, which uses coal as a fuel, with its further gasification and conversion into electrical energy in a solid oxide fuel cell (SOFC) stacks. The developed scheme differs from traditional circuits by using a gasifier with an inhibited circulating fluidized bed (ICFB). In addition, the anode-off gases are used in the combustion chamber of the gasifier to maintain endothermic gasification reactions. This technologies combination allows increasing the energy system efficiency. The paper also includes the results of tests of an ICFB gasifier and analyze the available electrical power of the SOFC stacks. Analysis dependence EMF from the produced generator gas composition showed no significant effect on the available power of the electrochemical generator. Developed scheme allow excluding from the process the gas cleaning from tar after gasifier, which allowed to increase the efficiency and reduce the metal capacity of the developed equipment.
About influence of non-sinusoidal currents and voltages on the amount of the electric energy
Authors: Vanin Valery , Bulychov Alexandr , Popov Maxim , Vasilyeva Olga , Shakhova Maria
Published: December 2018

The results of measurements of the harmonics components of the current, voltage, power of harmonics at the point of connection of electric receivers with a non-linear voltage-current characteristic are considered. It is shown that the amount of electric energy including the non-sinusoidality of the currents and voltages consumed by the non-linear load is less than the amount of the fundamental frequency energy. The difference between them is the harmonic distortion energy that causes extra losses to the electric networks. The voltage harmonic distortions at the measurement point exceed the normative values for 0.4 kV electric networks.
Assessment of heat pump efficiency for microclimate formation in a greenhouse
Authors: Tretyakova Polina
Published: December 2018

The article provides information about the ring heating system comprising heat pumps. The system is designed as a closed loop, which includes a pump, a thermal energy battery, and a heat pump. The evaporator is connected to the system of water intake from the well and the cooling system of air inside the greenhouse. The resulting thermal energy is consumed for the needs of heating and watering the greenhouse complex. We present a method for determining the dependence of the net present value on the temperatures in supply and return pipelines and temperature of low-potential heat source. The main economic indicators of the implementation of this system on a typical block greenhouse in the city of Tyumen are determined.
Structure of emergency automatics in UPS of Russian Federation
Authors: Koshcheev Lev , Lisitsyn Andrei , Popkov Evgeniy
Published: December 2018

There are emergency automatics systems (EA) widely used in Unified Power System (UPS) of Russian Federation. Main focus of article is centered on design principles of preventive automatics for stability control schemes (PASCS) as this automatics is the most complex type of EA. Features of PASCS are determined by modern state-of-the-art of digital technique and information technology, that decide the innovative developmental character of PASCS. Information about development and implementation of centralized emergency automation systems (CEAS) in power systems of Russian Federation is also given here.
Obtaining the frequency characteristics of a generator, operating in a power system for tuning channels of stabilization of an automatic excitation controller
Authors: Filimonov Nikita , Yurganov Alexey
Published: December 2018

In this work we consider the issues concerning tuning of the channels of stabilization for the automatic excitation controller at a real object using the frequency response. We present a test procedure for the generator operating in the power system. Also, we give some recommendations for selecting the white-noise parameters, by which the frequency response is obtained. The results are considered on the example of four-machine scheme of the power system (the Kundur scheme).
Some problem of centrifugal compressors upgrading
Authors: Sadovskiy Nikolai , Strizhak Leonid , Simonov Anatoliy , Sokolov Mikhail
Published: December 2018

The results of computational investigation of the influence of a gas labyrinth seals, oil end seals with floating rings and oil journal bearings lubricating layer stiffness coefficient on centrifugal compressor rotor critical speed are presented and analysed. The main principles of a method for axial forces acting on centrifugal compressor rotor calculation are listed. The method has been developed at the compressor, vacuum and refrigeration technologies department of SPbSTU. In addition, the estimation of method applicability in engineering calculations is given.
The choice of key geometric parameters in the numerical optimization of centrifugal compressor impellers
Authors: Neverov Vladimir , Kozhukhov Yuri , Kartashov Sergey , Ivanov Vyacheslav
Published: December 2018

The article deals with the choice of key geometric parameters and the range of their variation in solving the optimization problem of centrifugal compressor impellers using computational fluid dynamics. The study was carried out using Numeca Fine / Turbo package. The influence of more than 10 geometric parameters on the efficiency and the head of the impeller was considered. The influence degree evaluation of investigated optimization parameters was provide by changing the parameters value in a preset range and analyzing their impact on the efficiency and head of the impeller. As a result, the main geometric parameters of optimization, which should be considered first, were identified. Other parameters may not be considered within the optimization problem, and can be assigned to the standard values. In addition, recommendations on optimal ranges of parameter values were given.
Vortex methods in CFD problems
Authors: Grigor’ev Boris , Eliseev Artem , Iben Uwe , Lupuleac Sergey
Published: December 2018

Different mesh-using methods are widely applied to solve CFD problems. However, these methods are really hard to implement because of the problems associated with mesh construction, especially in complex-shaped domains. Using the mesh-free methods, e.g. vortex methods, could be the way to avoid these difficulties. This paper is focused on investigation the implementation features of vortex methods. Application of some vortex methods to modelling the incompressible flows around bodies is considered. Sometimes authors of vortex methods do not pay enough attention to details, which could complicate the practical application. These aspects of considered vortex methods are also discussed. In particular, it is shown that separate calculation of vortices with positive and negative circulations (the separate calculation approach) significantly improves the reliability of computations. Mathematical background of this approach is provided. The flow around the stable circular cylinder is considered as the test case. Several flow models are examined.
Information system for seamless positioning inside of objects under construction
Authors: Badenko Vladimir , Fedotov Alexandr , Bolsunovskaya Marina
Published: December 2018

Methods for seamless positioning of objects inside objects under construction to ensure the implementation of the principle “always and everywhere” and achieving centimetre positioning accuracy is proposed. The current state of work on the development of experimental samples of hardware and software complexes for seamless indoor and outdoor positioning of objects is presented. It is proposed to use radio-frequency technologies to solve the problem. The main methodological approaches and their first implementations are presented. The main feature of algorithms proposed is the implementation of a seamless transition when determining the position of the object in indoor and outdoor space with usage of an inertial system and radio-frequency positioning systems (in real time regime and without real time regime).
Developing a procedure for conducting a security audit of a software package for predicting storage system failures
Authors: Bolsunovskaya Marina , Shirokova Svetlana , Loginova Aleksandra , Uspenskij Mikhail
Published: December 2018

The aim of the work is to develop a procedure for conducting an information security audit of the software system for predicting data storage failures in order to identify existing threats to information security, evaluate information security tools, and improve the efficiency of existing information security tools and introduce new ones. It is necessary to monitor the current situation to ensure information security in organizations where data storage systems are used. For this purpose, an audit system has been developed, including both organizational measures and software and hardware parts.
The application of pesticides and mineral fertilizers in agriculture
Authors: Davydov Roman , Sokolov Michael , Hogland William , Glinushkin Alexey , Markaryan Artem
Published: December 2018

Regulation of using pesticides and agrochemicals application in agriculture is one of the important problem now, as also the problem of storage of mineral fertilizers and their improper using, which have negative influence on the chemical and the food security of the country. This paper discusses the features and benefits of monodisperse aerosols of pesticides in plant protection after a long-term research. A new line of development of science, engineering, industrial and innovative technologies - the author’s project “Monodisperse Anthropogenic Aerosols” is proposed. The measures for its implementation are presented.
The enhancement of operating properties of intumescent fire-protective compositions
Authors: Ustinov Andrey , Zybina Olga , Tomakhova Anastasia , Pavlov Sergey
Published: December 2018

The paper overviews the operational properties of charred layers which are forming as a result of thermolytical synthesis of intumescent coatings, and the ways of enhancing those properties using different additives mixed with initial intumescent composition. Methods including differential thermal analysis, thermogravimetric analysis, microscale calorimetry and scanning electron microscopy were used to investigate the modified intumescent compositions and the properties of charred layers formed from them. Results show that additives tend to change the microstructure of char which undergoes some transformations; it is proven by increase in volume and stability. Also it is shown that melamine-aldehyde resin was detected in the microstructure of char, and it is a step forward in forming a holistic conception of intumescents operating.
The development of a new method for making justified decisions by municipal authorities in the management of territories on the basis of the results of the environmental express-control of the state of various media
Authors: Rukin Egor , Moroz Angelina , Smirnov Konstantin , Davydov Vadim , Yushkova Victoria
Published: December 2018

The article considers the problems of assessing the ecological state of the water body and the surrounding area in the municipalities of St. Petersburg. The necessity of using the methods of express-control to determine the state of different media to obtain reliable operational information. A new method of making an informed decision on the territory management based on the results of express-control is proposed. The results of the study of the water body and adjacent areas are presented.
The simulation model for a flood management by flood control facilities
Authors: Davydov Roman , Antonov Valery , Molodtsov Dmitry , Cheremisin Alexey , Korablev Vadim
Published: December 2018

The rapid spread of storm floods over large areas requires flood management throughout the river basin by the creation an innovative system of flood control facilities of various functional purposes distributed in the area. The central part of the system is the hydro system with hydro power plant. In addition, the flood control facilities on the side tributaries with self-regulating reservoir are included in the system. To assess the effect of controlling extreme water discharges by flood control facilities, it is necessary to develop special mathematical models reflecting the specifics of their operation. Unified mathematical models of the operation modes of a hydro complex with hydroelectric power station and flood control facility are created. They are implemented in a computer program that provides the ability to determine the main parameters and operating characteristics of hydro systems when performing multivariate calculations in a wide range of initial data. This makes possible specifying the parameters and operation modes of each hydro system with the current economic and environmental requirements, to assess the energy-economic and environmental consequences in the operation of the system of flood control facilities distributed in the area. The article analyses the results of the extreme water discharge’s regulation by the hydro system on the main river and flood control facilities on the side tributaries, considering environmental requirements.
The simulations of helical blade interaction with ice
Authors: Abramova Ekaterina , Mashorin Georgy , Molev Yuri , Sogin Aleksandr
Published: December 2018

This paper presents the methodology for determination of the parameters of interaction between a rotary-screw vehicle and ice surface. The key parameter is the value of ice cutting force by means of a screw blade. The methodology allowed to obtain results, showing that the value of the cutting force depends on shape of the helical blade. Developed model of the cutting force allowed to conclude that that the width of the cut exerts the greatest influence on the cutting force, but depth and speed of the cutting have the less influence. Analysis of the study results provides the opportunity to find rational geometric parameters of the helical blade. The methodology can be applied for rotary-screw all-terrain vehicles designing.
Study of the performance of adobe brick coated for sustainable construction in the Algerian Sahara
Authors: Kerroum Nadir , Nouibat Brahim , Benyahia Azzedine , Redjem Ali
Published: December 2018

This article describes a study conducted to determine the ideal both traditional and stabilized composition of adobe as a building material, and to further refine an appropriate choice of coating composition for extended durability of these constructions in adobe: choose the suitable coating that fits the most with its substrate. The constructions in Z’gueg El Hadjadj [Laghouat town, Algeria] consist of adobe walls but also plaster that serves as a coating for these brick walls. The degradation phenomena of the building are considered in the adobe-coated couple, and consequently in the suitability of their compositions. The compatibility of plasters with adobes remains a major factor in the restoration and conservation of earthen constructions. This paper examines the results of the experimental characterization of the behavior of coated bricks, which consists of studying in the laboratory the water resistance: the drying-wetting test and the capillary rise test, as well as the complementary accelerated aging test: the abrasion test. These tests will be supplemented by another test, that of the adhesion, to see the compatibility of the coatings with their supports. The results, compared below, led to the conclusion that for capillary absorption and adhesion tests, a homogeneous coating in 3 layers could give more conclusive results. The drying-wetting test is recommended especially for bulk and surface treated samples.
Identification and partial characterization of a novel serpin fromEudiplozoon nipponicum(Monogenea, Polyopisthocotylea)
Authors: Roudnický Pavel , Vorel Jiří , Ilgová Jana , Benovics Michal , Norek Adam , Jedličková Lucie , Mikeš Libor , Potěšil David , Zdráhal Zbyněk , Dvořák Jan , Gelnar Milan , Kašný Martin
Published: December 2018

Background: Serpins are a superfamily of serine peptidase inhibitors that participate in the regulation of many physiological and cell peptidase-mediated processes in all organisms (e.g. in blood clotting, complement activation, fibrinolysis, inflammation, and programmed cell death). It was postulated that in the blood-feeding members of the monogenean family Diplozoidae, serpins could play an important role in the prevention of thrombus formation, activation of complement, inflammation in the host, and/or in the endogenous regulation of protein degradation.

Results:In silicoanalysis showed that the DNA and primary protein structures of serpin fromEudiplozoon nipponicum(EnSerp1) are similar to other members of the serpin superfamily. The inhibitory potential of EnSerp1 on four physiologically-relevant serine peptidases (trypsin, factor Xa, kallikrein, and plasmin) was demonstrated and its presence in the worm’s excretory-secretory products (ESPs) was confirmed.

Conclusion: EnSerp1 influences the activity of peptidases that play a role in blood coagulation, fibrinolysis, and complement activation. This inhibitory potential, together with the serpin’s presence in ESPs, suggests that it is likely involved in host-parasite interactions and could be one of the molecules involved in the control of feeding and prevention of inflammatory responses.
Improvement of Back and Leg Pain after Lumbar Spinal Decompression without Fusion
Authors: Bongartz Nicola , Blume Christian , Clusmann Hans , Müller Christian , Geiger Matthias
Published: December 2018

Background To evaluate whether decompression in lumbar spinal stenosis without fusion leads to sufficient improvement of back pain and leg pain and whether re-decompression alone is sufficient for recurrent lumbar spinal stenosis for patients without signs of instability.

Material and Methods A successive series of 102 patients with lumbar spinal stenosis (with and without previous lumbar surgery) were treated with decompression alone during a 3-year period. Data on pre- and postoperative back pain and leg pain (numerical rating scale [NRS] scale) were retrospectively collected from questionnaires with a return rate of 65% (n = 66). The complete cohort as well as patients with first-time surgery and re-decompression were analyzed separately. Patients were dichotomized to short-term follow-up (< 100 weeks) and long-term follow-up (> 100 weeks) postsurgery.

Results Overall, both back pain (NRS 4.59 postoperative versus 7.89 preoperative; p < 0.0001) and leg pain (NRS 4.09 versus 6.75; p < 0.0001) improved postoperatively. The short-term follow-up subgroup (50%, n = 33) showed a significant reduction in back pain (NRS 4.0 versus 6.88; p < 0.0001) and leg pain (NRS 2.49 versus 6.91: p < 0.0001). Similar results could be observed for the long-term follow-up subgroup (50%, n = 33) with significantly less back pain (NRS 3.94 versus 7.0; p < 0.0001) and leg pain (visual analog scale 3.14 versus 5.39; p < 0.002) postoperatively. Patients with previous decompression surgery benefit significantly regarding back pain (NRS 4.82 versus 7.65; p < 0.0024), especially in the long-term follow-up subgroup (NRS 4.75 versus 7.67; p < 0.0148). There was also a clear trend in favor of leg pain in patients with previous surgery; however, it was not significant.

Conclusions Decompression of lumbar spinal stenosis without fusion led to a significant and similar reduction of back pain and leg pain in a short-term and a long-term follow-up group. Patients without previous surgery benefited significantly better, whereas patients with previous decompression benefited regarding back pain, especially for long-term follow-up with a clear trend in favor of leg pain.
New Insights into Platelet Signalling Pathways by Functional and Proteomic Approaches
Authors: Jurk Kerstin , Walter Ulrich
Published: December 2018

As circulating sentinels of vascular integrity, platelets act as crucial haemostatic cells as well as important inflammatory and immune cells, whereas under pathological conditions platelets drive thrombotic as well as non-thrombotic diseases related to chronic inflammation. In addition, platelets serve as an important cellular model to study the biology and pharmacology of signal transduction pathways. Platelet inhibition and activation responses are mediated by multiple signalling networks, which are tightly regulated by balanced catalysis of protein phosphorylation and dephosphorylation through protein kinases and protein phosphatases, respectively. However, we are only at the beginning of understanding the complexity of interacting signalling pathways and their impact on platelet function. Here, we review current functional and proteomic approaches that lead to novel concepts of understanding the proteome, kinome and phosphatome of human platelets. A more in-depth understanding of both protein kinases and protein phosphatases using human platelets will contribute to evaluate their further diagnostic and therapeutic potential in inflammation- and immune-mediated diseases.
Apixaban for the Treatment of Chronic Disseminated Intravascular Coagulation: A Report of Two Cases
Authors: Janjetovic Snjezana , Holstein Katharina , Dicke Christina , Bokemeyer Carsten , Langer Florian
Published: December 2018

Characteristic features of disseminated intravascular coagulation (DIC) are the opposing risks of bleeding (due to consumptive coagulopathy and hyperfibrinolysis) and organ failure (due to widespread microvascular thromboses). The purpose of anticoagulation in DIC is to attenuate excessive thrombin generation and fibrin deposition. While heparins have been shown to be beneficial in this context, the safety and efficacy of direct oral anticoagulants have not yet been sufficiently addressed. Here, we report two patients in whom chronic DIC was stabilized upon administration of apixaban: an elderly male with aortic dissection presenting with significant mucocutaneous bleeding and a younger female with Klippel–Trénaunay–Weber syndrome presenting with multiple superficial vein thromboses (SVTs). In addition to an improvement in DIC parameters, both patients benefited clinically with resolution of bleeding symptoms and prevention of further SVTs, respectively. Oral apixaban thus showed promising safety and efficacy in the management of DIC caused by vascular abnormalities; still further investigations are needed to support these findings.