bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of preparation and properties of TiCN coatings by reactive plasma spraying
Authors: Qi Wenyan , Fu Siwei , Li Tian , Ye Fang , Guan Sensen , Chen Shaoyu
Published: August 2021

The TiCN coatings were successfully prepared by means of reactive plasma with spraying self-made composite powder prepared from 150°C to 350°C in the paper. Sucrose was used as a carbon source, using the means of Precursor body carbon, sucrose and titanium powder mixing at high temperature after the heat treatment furnace for carbonization. Finally, the titanium powder was wrapped by the carbon, so the composite powder was mixed more uniform and could react more fully. TiCN coatings could not be synthesized with the composite powder prepared the temperatures of 150°C and 250°C, because the sucrose was not carbonized totally and could not carbonize to synthesize TiCN with Ti and N2 in the process of spraying. TiCN coatings were prepared by spraying the composite powder under heat treatment at 350°C and which composed of Ti and C at a ratio of 1:3. The phase compositions, the morphologies, the hardness and the microstructures were analyzed. The results showed that TiCN coating was consisted of TiC0.2N0.8 phase and a few of TiN, the hardness of TiCN coating could reach 1000HV, the friction coefficient is about 0.45, the wear resistance of TiCN coating was lower compared with TiC coating because of the looser structure and the lower hardness.
Intelligent instrument fault diagnosis and prediction system based on digital twin technology
Authors: Gao Dawei , Liu Peng , Jiang Shengqian , Gao Xiyu , Wang Kun , Zhao Anran , Xue Yiming
Published: August 2021

In the context of informatization and intelligent manufacturing systems, digital twin technology provides new technical ideas for intelligent decision-making. Aiming at instruments with high cost and low output, this paper develops low-cost high-efficiency fault diagnosis system to realize rapid feedback and fault of fault diagnosis results. The system includes three layers: data layer, control layer and output layer. In the data layer, this uses MEMS sensors and Zigbee wireless transmission network to construct a data link the physical end and the virtual model. In the control layer, this paper stores the collected twin data through cloud technology, extracts and calls relevant data according to the function module and then maps it to the output layer. In the output layer, this paper constructs a characteristics interpretation system, which divides the test set and training set through the dynamic database, to complete the classifier and results output. The results are fed back to the judgment framework and control layer to evaluate the effects of fault diagnosis and prediction, which provides a new method for model optimization.
A framework for planning and scheduling shop floor logistics via cloud-edge collaboration
Authors: Lei Jingyuan , Hui Jizhuang , Ding Kai , Wu Linlin
Published: August 2021

Under the autonomous production mode, the production and operation process of smart shop-floor is operated by manufacturing units themselves. This paper describes a new framework for the order-driven products processing based on cloud-edge collaboration, in which the production-logistics tasks are planned and scheduled by the manufacturing resources at the bottom of smart shop-floor. The key enabled technologies and roadmap are further pointed out. The core idea of autonomous production mode is the autonomous communication and collaboration through an industrial network between all physical resources during production in a shop-floor. It is intended to serve as a reference for the managers while handling the flexible production organization and management based on the dynamic customer requirements.
New statistics for simultaneously machine incipient fault detection and monotonic degradation assessment
Authors: Hou Bingchang , Chen Yikai , Deng Yanqing , Wang Yuting , Wang Dong
Published: August 2021

Machine condition monitoring (MCM) has become an important tool to avoid sudden machine breakdown and gaining more economic profits. Tasks including early fault detection and monotonic degradation assessment are important in MCM. For the incipient fault detection, statistics such as kurtosis, Gini index are widely utilized, but they cannot give an accurately incipient fault detection time, and many fluctuations may exhibit. For the monotonic degradation assessment, root-mean-square are commonly used, however, it is sensitive to energy, and cannot show distinct degradation tendency in an early fault state. Those drawbacks have limited the development of practical MCM algorithms. To address those issues, this paper proposed four parameterized statistics for simultaneously early fault detection and monotonic degradation assessment. The four parameterized statistics can be health indicators and simplify the MCM algorithms, which can be beneficial to the practical MCM applications.
A data-driven approach for capacity estimation of batteries based on voltage dependent health indicators
Authors: Kong Jinzhen , Liu Jie , Chen Yikai , Wang Dong
Published: August 2021

Battery capacity estimation plays an important role in the normal operation of electric vehicles. In this work, we presented a data-driven approach for capacity estimation of batteries based on voltage dependent health indicators. A difference-based model of discharge voltage and capacity was built. Next, two health indicators are constructed from partial voltage curves, and correlations between capacity and health indicators are investigated. Afterward, the capacity estimation approach based on Gaussian process regression model is expounded. To validate the accuracy of the proposed method, a case study is carried out. Results demonstrate that RMSE and RMSPE of capacity estimation are lower than 1% compared with actual capacity.
Research on CLLLC Resonant Bidirectional DC-DC Converter
Authors: Lei Hou , Huizhuo Ma , Xingyu Chen , Kang Zhang
Published: August 2021

Based on the single-phase full-bridge LLC DC-DC converter, the LC series resonant network is introduced in the secondary side of the high frequency transformer to form the bidirectional CLLLC resonant DC-DC converter. Firstly, the bidirectional CLLLC resonant DC-DC converter was used for mathematical modeling. By extending the description function, the large-signal steady-state model of the converter was obtained, and the DC voltage gain when the DC-DC converter was running forward was deduced. The gain characteristics and frequency characteristics of the model are compared with those of the basic wave equivalent model. Secondly, the small-signal perturbation model of CLLLC DC-DC converter is modeled, and the small-signal perturbation is brought into the large-signal steady-state solution to obtain the transfer function when the CLLLC resonant converter is running forward. Finally, a 20kW CLLLC DC-DC converter is designed, and the simulation analysis is carried out to verify the correctness of the proposed scheme.
Study of the Modeling and Control Strategy for Active Power Filter
Authors: Huizhuo Ma , Lei Hou , Xingyu Chen , Kang Zhang , Fan Tang , Helin Lian
Published: August 2021

Improvement of active power filter’s performance through the reasonable control strategy is becoming a hot research for various counties’ scholars. In this paper, active power filter model is regarded as a starting point and the modeling process has been introduced in detail. For the following characteristics, such as harmonic current detection must be real-time and accurate, active power filter’s uncertainty and nonlinear, the harmonic current detection method which is based on instantaneous reactive power is used. In this way, harmonic current, reactive and negative sequence current in grid can be accurately tested out. The active power filter which is developed according to this current real-time detection algorithm can balance asymmetrical three-phase load. The simulation model is built in MATLAB/simulink. The simulation results show that this active power filter can be more rapid, accurate compensate harmonic current than the conventional active power filter.
Three-dimensional Simulation of Forced Convective Flow and Heat Transfer in Air-Cooled Motor Stator
Authors: Ma Fan , Dong Haihong , Liao Yigang , Wang Chao
Published: August 2021

The reliable prediction of cooling medium velocity and stator temperature distribution is very important for a running motor to ensure the temperature rise of stator below the limit. In this paper, taking the stator ventilation duct of an air-cooled motor as the research object, a 3D physical model including the iron core, the windings, the stator ventilation duct and the main insulation was established. In order to fully reveal the characteristics of forced convective flow and heat transfer in air-cooled motor stator, the fluid field and temperature field were calculated by using finite volume method. The radial and axial distribution characteristics of the fluid field were analyzed deeply. It’s shown that the velocity decreases in the axial direction on the half of the axial plane and varies greatly in the radial direction. The temperature distribution in the main insulation layer of the stator was elaborated emphatically. The temperature of the insulation material along the length of the slot and the temperature difference between inner and outer insulation were discussed in detail. Based on the experimental results, the reliability of the calculation method was evaluated and the relative error is within 15%.
An Efficient FHE Radix-2 Addition Algorithm in BGV Scheme
Authors: Hou Zongsheng , Zhang Neng , Liu Leibo
Published: August 2021

Fully homomorphic encryption (FHE) is a novel encryption method that can perform operations on encrypted data. The performance of applications based on FHE is still low due to the high computational complexity of operations on the ciphertext. In this paper, we proposed an efficient FHE radix-2 addition algorithm in BGV scheme, called Optimized Cheon’s SIMD Adder. It is an optimization of Cheon’s SIMD Adder. The proposed adder uses the previously calculated results as much as possible to calculate the new result, so that it can keep the circuit depth as 0(log(μ)) and reduce the number of homomorphic multiplications. We also compared the weighted computational complexity (WCC) between this work and Cheon’s. The WCC of this work is only O (μ), while Cheon’s is 0(μ· log (μ)). At the end of the paper, we implemented the proposed addition, which improves the calculation speedup by 1.3 ~ 1.4 times for 8 ~ 512- bit adders compared with Cheon’s SIMD Adder.
A New Radar-Embedded Communication Waveform with Low Computational Complexity
Authors: Zhang Chengan , Li Baoguo , Du Zhiyi
Published: August 2021

Radar-Embedded Communication (REC) is a covert communication technology that utilizes a radio frequency (RF) tag or transponder to embed the communication signal into the radar backscatter. The RF tag must be triggered by the radar signal and quickly generate the required communication waveforms so as to ensure that these communication symbols can be timely and effectively embedded in the radar backscatter pulse. Such an operation poses a great challenge to the response speed of the tag transponder. The traditional method is based on multiple eigenvalue decompositions to generate quasi-orthogonal communication waveforms, which requires a large amount of calculation. This paper proposes a strategy that requires only one eigenvalue decomposition operation. However, such a strategy makes it possible to generate completely orthogonal communication waveforms, and at the same time, it will contribute to a great reduction in the computational pressure of the RF tag. In addition, by simulation analyses, the communication waveform design strategy proposed in this paper does not take the reliability and the low probability of interception (LPI) of the waveform as the cost. On the contrary, under some conditions, communication reliability and LPI characteristics can be improved.
Improved Chinese Short Text Classification Method Based on ERNIE_BiGRU Model
Authors: Cheng Xue , Zhang Chen , Li Qingxu
Published: August 2021

This paper is aimed at traditional word embedding models and Bidirectional Encoder Representations from Transformers (BERT) that cannot learn text semantic knowledge, as well as convolutional neural network (CNN) and Bidirectional long short-term memory (BiLSTM) unable to distinguish the importance of words, proposing an improved Chinese short text classification method based on ERNIE_BiGRU model. Firstly, learning text knowledge and information through the Enhanced Representation through Knowledge Integration (ERNIE) enhances the model’s semantic representation capabilities. Secondly, considering that CNN can only extract local features of the text while ignoring the semantic relevance between contextual information, and the Bidirectional Gating Recurrent Unit (BiGRU) is simpler, has fewer network parameters and faster calculation speed than the BiLSTM, the combination of CNN and BiGRU enables the model to capture both local phrase-level features and contextual structure information. Finally, according to the importance of features, the attention mechanism is used to assign different weights to improve the classification effect of the model. The experimental results show that the ERNIE_CNN_BiGRU_Attention (ECBA) model used in this paper has achieved good results in the task of Chinese short text classification.
ISDM-Rosleskhoz operation and evolution experience
Authors: Balashov I V , Loupian E A , Bartalev S A , Burtsev M A , Mazurov A A
Published: August 2021

The paper marks the 15-th anniversary of the Wildfires Monitoring Information System of the Federal Forestry Agency (ISDM-Rosleskhoz). Creation and development of the system was partaken by many organizations, including the Aerial Forest Protection Central Base (Avialesookhrana), Space Research Institute of the Russian Academy of Sciences (IKI), Center for Forest Ecology and Productivity of the Russian Academy of Sciences (CEPF RAS), State Research Center “Planeta”, OOO Inkom, Institute of Solar-Terrestrial Physics of the Siberian Branch of the Russian Academy of Sciences (ISTP SB RAS), Saint Petersburg Forestry Research Institute (SPbNIILH). The system provides uniform near real-time information necessary for forest fires and their impact monitoring all over the Russia territory and border areas. The paper highlights main trends and key stages of ISDM-Rosleskhoz development and evolution during the entire operation time span. This constant evolution has made and is keeping the system as the largest fires monitoring industrial system operated by Forest Protection Services both in Russia and in the world. The paper also briefly provides major development directions of the system for the nearest years.
Application of online training in the education of specialists for the production of second generation biofuels
Authors: Fedorova O V , Akim E L , Kuznetsov A G , Pekarets A A
Published: August 2021

In a circular economy, wood is a valuable product, the use of which must be rational. Integrated wood processing includes the use of production waste, for example, when sawing and planning. Raw materials for the production of pellets and fuel briquettes are sawdust, shavings, slabs. The production of second generation fuels is an extension of the life cycle of forestry and woodworking products. The production of pellets made by pressing crushed wood particles has changed the technology of energy use of wood in the ECE region. And, in turn, there was a need for specialists and new jobs.
Possibilities of near real-time forest cover damage estimation based on fires radiative power data
Authors: Lozin D V , Balashov I V , Loupian E A
Published: August 2021

The paper proposes a solution to the problem of operational assessment of forest cover damage based on the fire combustion intensity data. Approaches to the assessment of the considered phenomena are presented. An algorithm for comparing data to study the relationship between them is described. The results of such a comparison are discussed, and on that basis, a method is proposed for the rapid assessment of the degree the forest cover is damaged by fires. The integral estimates of the dead forest areas obtained using the described methodology throughout the country are compared with the corresponding actual values. Summing up the results of the work done, the effectiveness of the developed method is evaluated.
Inter-annual variability of the forest area of different types of surface of the Leningrad region
Authors: Martyn I , Petrov Y , Stepanov S , Abramov V , Sidorenko A
Published: August 2021

In connection with the vast territories of the Russian Federation, accounting for the area of forests and other objects of the forest sector and their changes becomes problematic. At present, this accounting is best carried out thanks to the methods of remote sensing of the Earth. This article presents an example of analyzing the inter-annual variability of forest land areas in the Leningrad Region for the period 2015-2019, according to remote sensing data, using statistics without the use of complex algorithms. All the data obtained are summarized in a table. The analysis of variability of land areas by methods of mathematical statistics is carried out and the year of disappearance of this type in the territory of the region is determined for the most vulnerable types.
Digital twin of wood working enterprise
Authors: Masaev S N , Minkin A N , Yu Troyak E , Khrulkevich A L
Published: August 2021

A review of scientific papers has shown that digital twins are very common for modeling the states of physical objects. It is relevant to consider the creation of a digital twin of an enterprise to obtain various assessments in management, taking into account the human factor. In the research, the impact of the human factor is assessed by the digital twin and staff competencies. The system of goals of staff competencies stands for: cognitive, affective, psychomotor. An enterprise model is created from the description of the set of events taking place on it. Each event is mapped to an element of staff competencies target system. The resulting set of staff competencies is estimated by a universal (integral) indicator. The dynamics of the universal indicator characterizes two modes of operation of the enterprise. The first operating mode is normal. The second mode of operation is based on the implementation of staff competencies. Taking into account the competencies of personnel by Bloom’s taxonomy allows you to determine their interconnection: cognitive, affective, psychomotor. It correlation depends on the work performed by the employee and the influence of the external environment. It depends on the efforts of the employee as a learner.
Digital forest pedagogy in context of distance learning
Authors: Pastukh O A , Zhuk Yu A
Published: August 2021

The article tells of the actual problems of the introduction of digital technologies in the higher education system. The development of digital technologies in all spheres of life is supported at the state level and by the general public. Digitalization is a new social situation.The article describes the current problems of digitalization of education. A wide range of possibilities of digital technologies in the educational process of the St. Petersburg State Forest Technical University named after S. M. Kirov (SPbFTU) is considered.It is concluded that the digitalization of education changes the content of the courses taught, as well as the presentation of information, it is not only presentations or videos, it is already direct connections to information networks, databases, forums.
Forecasting model of forest management fire index at the thematic area of the Trans-Baikal Territory
Authors: Istomin E , Sidorenko A , Petrov Y , Stepanov S , Martyn I
Published: August 2021

The article presents a forest fire forecasting model based on recursive filtering of the fire weather index. The relevance of the study is presented, statistical data are presented, including economic aspects, on the basis of which the scientific task is set. For the approbation, the fundamental issues to be solved have been identified. A geo-information resource is considered that assists in the choice of the study area, while calculating a complex indicator of fire hazard. Data were sampled on the basis of Columbia University’s International Research Institute for Climate Prediction. A recursive filter based on the combination of Kalman and Levinson algorithms is used as the central part of the model. The program model of the filter is presented. Approbation was carried out with a visual result in the form of a predictive assessment graph. General results of work are substantiated.
Hard-to-recover oil reserves as a factor of socio-economic growth of resource regions
Authors: Filimonova IV , Provornaya I V , Komarova A V , Yu Nemov V , Chebotareva A V
Published: August 2021

The article considers the main classification features of the category of hard-to-recover oil reserves. The analysis of changes in the dynamics of production of hard-to-recover oil in Russia is carried out. The relationship between the development parameters of the oil and gas complex and the level of socio-economic development of resource regions using the method of hierarchical cluster analysis is investigated.
Disintegration of a roof coal while developing powerful seams with a controlled coal release
Authors: Klishin V I , Anfyorov B A , Kuznetsova L V , Varfolomeev E L , Borisov I L
Published: August 2021

The technology of thick seam development with roof coal release on the face conveyor which allows increasing the coal flow, reducing the losses and stand-by-time of the stope is worked out by the Institute of Coal of FRC CCC SB RAS. Disintegration of roof coal preparing it for release can be done during gradual advancing of a stope or in advance, applying the method of interval hydraulic fracturing before starting stoping.
The influence of coal and enclosing rock fracturing on the management of the rock massif during the exploitation of thick coal seams by the longwall top coal caving technology
Authors: Klishin S V , Opruk G Yu , Varfolomeev E L , Borisov I L
Published: August 2021

The methods for the disintegration of coal-bearing rock massif have been developed that allow eliminating the areal hanging of roofs in the longwall faces and their dynamic impacts on mechanized complexes, to ensure the safety of reused mine workings in the coal face operation area, and also to create a system of cracks in the coal seam upper side along the entire length of the face and increase the efficiency of preliminary degassing without creating a large number of intermediate mine workings. A technique for the numerical study of reservoir properties of rocks containing a system of cracks is proposed. An algorithm and software for creating two-dimensional stochastic systems of cracks with a given distribution of the coordinates of their centers, lengths, and orientations are developed. Based on the finite element method, the problem of fluid filtration in a fractured massif is numerically investigated. The influence of parameters of crack systems on the filtration properties of the medium is shown.
Developing the methodology on creating unified criterion for diagnosing the mining machinery equipment defects
Authors: Gerike P B , Eshcherkin P V
Published: August 2021

In the framework of the research the consolidation of the results on analyzing vibration parameters, registered during operation of electric shovel energy-mechanical equipment (of EKG and ASH type) was fulfilled. It was done in the respect of solving the problem on improving vibration control methodology and developing unified criterion for diagnosing and forecasting technical condition degradation of open-pit excavator dynamic equipment. Methodology for creating the algorithm for unified diagnostic criteria on the basis of mathematical processing of the existing vibro-diagnostic properties during detecting the defects in rolling bearings and jointing sleeves used in designing electric shovels was worked out. The effectiveness of the introduced approach for selecting diagnostic methodology of obtaining initial data suited for developing unified diagnostic criteria was proved. The results showed the effectiveness of the methodological approach for creating the algorithm of developing unified criterion for detecting technical condition and forecasting the degradation processes of rolling bearings and jointing sleeves used in designing electric shovels.
Substantiating topicality of injectable localizing and deactivation of coal seams prone to endogenous spontaneous combustion
Authors: Mayorov A E , Patrakov Yu F , Semyonova S A , Abramov I L , Nepeina E S
Published: August 2021

The analysis for possible development of endogenous fires in coal seams prone to oxidation and spontaneous combustion is done. The coal free surface area is taken as a forecasting criterion for estimating the state of the zones of broken condition. The effectiveness of applying fracture plugging (cementing) technology for injectable localizing and deactivation of the massif is substantiated. The conception for further studying of the processes for controlling physical and chemical characteristics of a seam considering native properties of coal is formed.
The concept of using computer vision in control of autonomous transport
Authors: Kizilov S A , Nikitenko M S
Published: August 2021

The paper discusses technologies of control over unmanned self-propelling transportation vehicles in enclosed industrial areas based on computer vision with active adjustable mapping of the vehicle motion path. The authors describe substitution of LIDAR sensor for a light net mapped on the road surface.
Gas drainage in coal mines: current condition and prospects
Authors: Nikitenko S M , Glukhikh S A
Published: August 2021

The article reviews scientific and engineering information on history, current condition and prospects of use for various technologies of gas drainage in coal mines, including the use of methanotrophs.
Selection of energy-technological modes of submerged-arc welding with silicomanganese slag for parts of mining equipment
Authors: Kozyrev N A , Usoltsev A A , Kryukov R E , Mikhno A R , Ya V , sellermayer T
Published: August 2021

The paper presents studies of the influence of energy-technological modes of welding on the physical and mechanical properties of welded joints obtained by submerged-arc welding, with the use of slag from silicomanganese production for parts of mining equipment. To study the welding and technological properties, we used a welding flux of 0.45-2.5 mm fraction based on a silicomanganese slag with a chemical composition, wt. %: 0.42 FeO, 16.22 MnO, 29.00 CaO, 41.34 SiO2, 6.53 Al2O3, 1.33 MgO, 0.24 S, 0.022 P, 0.008 ZnO, 0.031 C, 0.31 F, 0.15 TiO2, 0.025 Cr2O3. Automatic welding of 09G2S low-alloy steel under this flux was carried out by Sv-08GA wire. Various welding modes were investigated to ensure the required penetration depth and the absence of external defects (pores, cracks, cavities). Based on the data obtained, the dependences of the influence of the parameters of the welding mode on the mechanical properties of welded samples are plotted. It is shown that changes in the parameters of the current strength, welding speed and voltage can affect the physical and mechanical properties of the weld, as well as the transition of sulfur and hydrogen into the weld.).
Justification of the possibility of application of a neural network for predicting methane release during underground mining of gas-bearing coal seams
Authors: Dvoryanchikov M V , Pavlova L D
Published: August 2021

The mathematical apparatus of neural networks is presented and its application is substantiated for solution of the problem of predicting methane release in underground coal mining. An example of using a neural network for a regression problem in the Matlab software package is given.
Human resources and health and safety management in the production environment of a loading and transport enterprise
Authors: Pristupa Yu D , Shishkina S V , Pavlova L D , Fryanov V N
Published: August 2021

The directions for the improvement of the level of labor protection through personnel management in the process of recruitment, the development of competence and the preservation of the health of workers are substantiated. Using the example of loading and transport enterprise activities, the role of a person as a guarantor of the improvement of a complex organizational and production system safety is determined.
Use of frequency converters in the stator circuit of a doubly-fed induction motor of a hoisting unit
Authors: Yu V , Ostrovlyanchik I , Popolzin Yu , Kubarev V A , Marshev D A
Published: August 2021

One of the currently accepted options for modernizing an induction electric drive is the use of a frequency motor control. In this case, a frequency converter is connected to the motor stator with the ability to control the voltage parameters at its output. Usually, frequency control is applied to induction squirrel-cage motors, including special machines designed for frequency control. In this case, as a rule, the frequency changes “down” from the nominal frequency of the voltage on the stator of the machine, and the speed control range is determined by the minimum frequency of the voltage applied to the stator. At the same time, for motors used in the electric drive of hoisting installations, the speed control range is limited to 2:1 due to the deterioration of the properties of the magnetic system of the machine. Speed regulation below half the rated speed can be carried out using a controlled rotor current converter.
Control system of induction motor drive of a hoisting unit with a controlled current converter in the rotor circuit
Authors: Yu Ostrovlyanchik V , Yu Popolzin I
Published: August 2021

The use of a double-feed machine circuit is a promising way to modernize induction motor drives of mine hoisting installations. The main problem of using doubly-fed electric machine in the electric drives with a large range of speed control is the release implementation and machine operation of after it at low speed. Existing implementations of electric drives based on a doubly-fed machine (DFM) assume the use of additional resistors in the rotor circuit (rotor station) for releasing the brakes, which complicates the control circuit and significantly reduces the reliability of the drive. In this case, the electric drive circuit with additional active resistances in the rotor circuit has optimal starting characteristics, since a change in the active resistance of the rotor does not cause a change in the critical moment, and, therefore, in the overload capacity, which makes it possible to implement the release mode. It is possible to preserve the advantages of regulating the DFM speed by changing the active resistance of the rotor by using an imitation of its change. The article is devoted to the study of the possibility of implementing such mode using a controlled current converter in the rotor circuit.
Detection of centrifugal turbocompressor surge by drive motor current
Authors: Kipervasser M V , Gerasimuk A V
Published: August 2021

The article deals with the case of surging of a turbocompressor unit. Mathematical modeling of the situation under consideration is carried out and its influence on the stator current of the electric motor is estimated. The analysis of the simulation results with the corresponding conclusions is made. A surge detection device is proposed.
Development and substantiation of technological solutions for the transformation of organic matter of fine-dispersed waste coal
Authors: Murko V I , Temlyantsev M V , Litvinov Yu A , Volkov M A , Baranova M P
Published: August 2021

A plant for liquefying organic matter has been create to solve the problems of using low-grade coals and waste coal utilization. The results of the performed studies are presented and the prospects for the solution of existing problem are shown, initial data are obtained for creating a pilot sample of the technological complex.
Corrected mathematical model of transverse oscillations of ropes and shafts of mine hoists
Authors: Borshchinsky M Yu , Kubarev V A , Ignatenko O A
Published: August 2021

The oscillating processes of the rope and the shaft in small movements provoke fretting wear and corrosion at the attachment point. On the basis of the Fourier method, an improved model of oscillating processes has been developed that significantly extends the functionality of the variable separation method. The model adequacy is confirmed.
The assessment of resilience of Russian resource-based regions
Authors: Kagan E S , Goosen E V , Pakhomova E O , Nikitenko S M
Published: August 2021

The article examines contemporary approaches to and the evaluation of “resource dependence” and “resource-based regions”. Resource dependence analysis is based on the data of the Russian Federal State Statistic Service (Rosstat) and customs service statistics from 2005 to 2016. The starting point (2005) was chosen to marking the end of economic restoration after the 1990s steep decline. Moreover, it was in 2005 when the calculation of mining industry share in gross regional product began. 2016 is the last year available. The authors suggest resilience as a new criterion for choosing an optimal development trajectory. For the assessment of the resilience of Russian resource-based regions the authors use the approach of R. Martin, P. Sunley, et al and methods of coefficients calculation for adaptive resilience and resilience adaptability. The concept is regarded as the ability of a region to mitigate external and internal shocks in a short-term perspective, and to choose an optimal development trajectory in a long term one. Results of this study show that 19 out of 85 constituent entities of Russia may be defined as resource-based (resource-dependent). Their resource dependence is different, varying from monoregions to region’s specialization in mining (resource-dependent regions). Analysis of their resource dependence dynamics shows that in most regions resource dependence grows, and their resilience assessment shows that most regions are resilient and tend to retain the selected development trajectory in a long-term perspective.
Industry 4.0. and an upgrade of the business models of large mining companies
Authors: Kagan E S , Goosen E V , Pakhomova E O , Goosen O K
Published: August 2021

With the depletion of easily accessible deposits and the transition of the industry to the Industry 4.0 principles the need for more than just increasing production volumes and applying new technologies including automation and modern digital technologies, but also for solutions to a number of organizational and socio-economic problems faced by this sector. All these problems are in one way or another related to the change in the business model of extractive companies. Under these conditions, studying the features of the business models of the major Russian companies in the extractive sector under the transition to the Industry 4.0 is a relevant research task. The purpose of this article is to characterize the features of business models of large Russian extractive companies operating in the fuel and energy complex and to describe the possible directions of their transformation under the influence of Industry 4.0. Our analysis of the business models of the major Russian mining companies and comparison to their foreign counterparts showed a certain conservatism in Russian companies and the lag in the implementation of digital platforms, despite the interest of companies’ management in using digital technologies. This is largely due to the low willingness of most companies to complicate their business models and to implement digital transformation. Such trends can be explained by the fact that companies tend to choose a vertically integrated model. They are in the early stages of digital transformation and mainly focused on operational aspects. In most Russian mining companies, the level of automation of production and administrative processes is low, and the use of digital technologies is still limited mainly to pilot projects. To achieve a systemic effect from digitalization, it is necessary to combine the efforts of all interested parties – the government, companies, the innovation community, and academic circles.
Short-and long-term factors of Kuzbass resilience (based on expert interviews)
Authors: Matveeva E V , Goosen E V , Nikitenko S M , Kavkaeva O N
Published: August 2021

Resource regions and their resistance to stress require a separate study. The article develops the author’s interpretation of the concept of stress resistance, identifies four main indicators of stress resistance-economic, social, political and psychological. The aim of the article was to identify indicators for assessing the stress resistance of a region, as well as the possibility of using this concept to analyze the current socio-economic and political situation in the context of the global crisis caused by the COVID-19 pandemic using the example of one of the resource regions-Kuzbass. The main research method was the expert interview method, which made it possible to find “common ground” in understanding the sustainability of the development of the region, as well as to see different facets of the manifestation of sustainable and unstable development on the example of Kuzbass, which are based on certain not only subjective, but also objective reasons, as well as to outline further facets of research. When analyzing crisis phenomena mainly in the economic sphere, the model of economic stress resistance by R. Martin, R. Sunley and others is used. The research was based on expert interviews among representatives of the scientific and expert communities of Kuzbass, representing the higher education system, regional media, business community, and non-profit organizations. During the study, 10 experts were interviewed. The study showed that the highest stress resistance is demonstrated by the sphere of medium and large business, there was practically no deterioration of the situation in the media sphere, education, healthcare (to a lesser extent sports and culture) managed to adapt to new conditions, but the “precariousness” and instability of the situation is most traced in the activities of the non-profit sector.
The model of a permanent magnet DC motor in time domain and frequency domain based on Bond Graph modelling and design of position control using PID controller
Authors: Korsoveczki Gy , Husi G
Published: August 2021

During the research work, the modelling of a permanent magnetic DC (PMDC) motor was realised in time domain and frequency domain via 4 different types of model construction. To achieve this, the Bond Graph model of the motor was determined, and based on them the system equations were defined in time domain firstly and then in frequency domain by using the Laplace transform. According to the system equations in time domain, the state-space model of the motor was also realised and implemented. Based on the system equations in frequency domain, the transfer function of the position control loop was realised. As the further part of the research work, PID control-based position control was designed in both time domain and frequency domain. The controller was tuned according to the Ziegler-Nichols method. Finally, the models were compared from the point of view of behaviour during the tuning process. The models were implemented in LabVIEW environment produced by the National Instruments.
Analysis of defects in the braking systems of commercial vehicles
Authors: Popa M F , Capătă D M S , Burnete N
Published: August 2021

The field of commercial vehicles has consolidated an indispensable place in society through aspects such as: the continuous development of delivered performance, increased reliability, raising comfort standards and increasing traffic safety to unprecedented levels. However, increasing performance and improving the braking process are aspects that require increased attention and can be achieved by timely identification of system defects and analysis of determinants. The complexity of current systems, both the complexity of braking systems and the overall complexity of commercial vehicles, sometimes make it difficult to diagnose and repair, but they come with significant advantages. The current study analyses data on the wear of the elements of the braking system at several trucks and identifies the main trends. In addition to data on wear and maintenance, this study also examines errors in electronic control units, looking to identify dangerous situations that can lead to issues such as: reduced braking capacity; premature decommissioning of the elements in the braking system; increasing downtime in the workshop or increasing maintenance costs. The identified solutions are based on the analysis of the frequency of errors and their distribution.
An analysis of European Union’s circular economy indicators with focus on materials: implications for the manufacturing industry
Authors: Păcurariu R L , Lakatos E S , Nan L M , Bacali L , Seitoar D
Published: August 2021

The paper aims to emphasize the contribution that manufacturing industry can have to meet the Circular Economy (CE) scope related to the use of resources. First, we presented the CE concept and the framework in Europe, the monitoring framework and also, we noted some aspects of manufacturing industry related to CE. Then, we performed an analysis of the secondary raw material data, which is one of the representative indicators of CE, in order to see the state of circular economy related to the resources in European Union Member States. The results showed that the resource circularity is lowest in Europe, the states which can be remarked are Germany, Netherlands, and Belgium. Highlighting these aspects, some conclusions were formulated, the most evident is that the manufacturing industry has a very important role on the CE transition, consisting in the resources fact implicated. The manufacturing industry can choose to use secondary raw materials instead of virgin raw materials, can improve resource efficiency through the technologies used in production processes and can address the circularity of a product, being an important CE actor.
Transforming 3D printed CNC prototype into a plotter
Authors: Culda LI , Muncut (Wisznovszky) ES , Erdodi GM
Published: August 2021

We often hear about numerical control or CNC abbreviated. With this type of control, we can automatically control various processing tools such as: drills, lathes, milling cutters, rapid prototyping printers, etc. The instructions they need to receive will be in the form of a Gcode sequential program generated by the CAD / CAM drawing and manufacturing program. In the case of 3D printers, the CAD / CAM information is passed through a slicer specific to that printer, which “cuts” the object into printing slices. CNC systems are used today for virtually any process that has movements and operations, including laser cutting, hole punching, fabric cutting, welding, etc. because most CNC systems built today are 100% electronic. 3D printing of a CNC was a real challenge that aimed to understand the principles of obtaining and operating a CNC. I found that we basically have 3 devices with the same basic principles: CNC milling cutter, 3D printer and plotter. So I created a CNC that I turned into a plotter just to highlight the above.
Financial performance management and economic cycle variations. Evidence for textile industry
Authors: Tudose M B , Avasilcai S
Published: August 2021

The study analyses the dynamics of the financial performance of the companies in the textile industry in Romania and aims to identify its main determinants, corresponding to the different stages of the economic cycles. The selected sample was mixed; therefore, the econometric analysis (based on panel data) was performed on accounting data collected from secondary sources (for 2000-2019). Because some of the companies in the sample showed negative financial results, the financial performance was assessed based on sales’ volume. The regression model used included seven determinants related to the company (internal determinants) and three external variables (GDP growth rate, inflation rate and unemployment rate). The results of the analyses indicated that (for the whole period) 51% of the sales dynamics can be explained due to the variation of the determinants included in the model. The analysis at the level of internal determinants indicated that all seven variables have a significant statistically influence on financial performance. From the perspective of macroeconomic determinants, the study showed that performance is negatively and significantly correlated with the inflation rate and unemployment rate. Applying the regression model to distinct periods (pre-crisis, crisis and post-crisis) provided very useful information from a practical point of view.
Productivity assessment of the Romanian construction industry using Malmquist Productivity Index
Authors: Cristea C , Cristea M , Șerban F M , Făgărășan C , Stoenoiu C E
Published: August 2021

The construction industry is one of the largest economic sectors worldwide. It is essential that the firms operating in the construction industry to evaluate accordingly their productivity change both in economic depression and when there is registered an expansion in the economy. This paper investigates the productivity changes of the Romanian enterprises from construction industry during the period of 2006 through 2019 by using the Malmquist Productivity Index. Four input variables and two output variables have been employed for measuring the change of construction productivity. The findings indicated that Malmquist Productivity Index can be effectively employed for assessing the productivity changes of companies. The results indicated that the majority of the Romanian companies exhibited better performance in terms of technical change while efficiency change regressed. This investigation provides valuable information for decision makers in order to enhance the performance of the Romanian construction industry organizations.
Insular genetic algorithm for operational management
Authors: Vîlcu A , Herghiligiu I , Verzea I , Pîslaru M
Published: August 2021

Problems in the operational management that involve the calculation on graphs are numerous, being encountered in many economic fields: transport problems, problems of resource allocation, logistics problems. Within these problems are found the problems of partitioning graphs with partitions that meet different partitioning criteria. The paper presents a case study for the problem of partitioning graphs - organizing the graph, practical applicability of the problem, partitioning function, method of solving the problem by using three genetic algorithms working individually on islands of problem solutions, changing synchronously with each other solutions, and the application of the algorithm on a numerical example. Finally, the paper proposes conclusions and future directions of development.
A comparative experimental study for dry and wet collisions
Authors: Ciornei F-C , Alaci S , Bulai P , Romanu I-C
Published: August 2021

The collision between polyurethane prismatic foam and a dropping steel ball is investigated experimentally. Because the foam presents large deformations, an analytical model is not available. The impact is studied on a test rig from laboratory, for dry foam and for the mineral oil wetted foam. The post impact velocity is found measuring the flight time and the coefficient of restitution and lost energy are estimated. For the dry impact case the damping effect is smaller than for the case of oil-wetted target.