Olga Porkuian - Academia.edu (original) (raw)

Papers by Olga Porkuian

Research paper thumbnail of Twice displaced, but unconquered: The experience of reviving a Ukrainian university during the war

Problems and Perspectives in Management

A new wave of relocation of universities from the war zone has resulted from the negative consequ... more A new wave of relocation of universities from the war zone has resulted from the negative consequences of the hostilities and the temporary occupation of the territories of Ukraine by the russian federation. The challenges of today have a multidirectional impact, especially on universities that have been displaced twice. The relocation of each university is a unique experience, and academic management is the object of modern scientific research. Therefore, the paper aims to highlight the experience of gaining resilience and developing the sustainability of Volodymyr Dahl East Ukrainian National University (hereinafter V. Dahl EUNU) during the evacuation in 2014 from the city of Luhansk to the town of Severodonetsk, and in 2022 along the entire movement path to the city of Kyiv. It is determined that the main resources are human and social capital, which allow not only counteractong the challenges of martial law, but also ensuring the restoration of the system and its further develop...

Research paper thumbnail of Comparison of Studies of Dangerous Cargo Flow Distribution Between Rail and Road Transport

TRANSBALTICA XI: Transportation Science and Technology, 2020

The article compares the results of different studies of dangerous cargo flow distribution betwee... more The article compares the results of different studies of dangerous cargo flow distribution between rail and road transport. The dependency has been examined by example of actual data that assesses the percentage ratio variation of transported dangerous cargo by rail and road transport when the total quantity of cargo changes by one percent. The results of this study have been compared to the results of expert survey on the issues of competitiveness of dangerous cargo transportation between rail and road transport.

Research paper thumbnail of Study of Field Testing on Car Body Vibrations of Moving Passenger Car with Wheel Flat

TRANSBALTICA XI: Transportation Science and Technology, 2020

The article analyze the methodology of experimental investigations of railway vehicles under real... more The article analyze the methodology of experimental investigations of railway vehicles under real operating conditions. The aim of the research is to determine the vertical and lateral accelerations of the carbody of passenger car with a wheel flat by running along the same track at different speeds. Statistical analysis of the obtained data was performed. Experimental results were evaluated using shock acceleration ratio and Sperling ride index was calculated. General conclusions are given.

Research paper thumbnail of Research of the automatic control system of belt conveyor on the technical basis of the industrial controller Schneider Electric

S u m m a r y . The results of the studies of complex system of automatic control of processes of... more S u m m a r y . The results of the studies of complex system of automatic control of processes of the transportation and the crushing of the ore been presented. The principles of control been based on the measurement of temperature field on the zone of the friction. The efficiency of the approach confirmed by the results of theoretical and experimental research of the control system based on industrial controllers Schneider Electric. K e y w o r d s . Industrial controllers, belt tension control, mathematical models of distributed parameters.

Research paper thumbnail of Some algorithms of computer algebra

The article describes one of the methods for computing determinants without using fractions propo... more The article describes one of the methods for computing determinants without using fractions proposed by Bareiss. This problem has a clear algorithmic character in nature and refers to the field of computer algebra. The implementation of this algorithm is proposed in the known Maxima system of symbolic computations. In addition, this method makes it possible to get enough convenient formula for the calculation of the matrix of unitriangular transformation of a quadratic form to a canonical one.

Research paper thumbnail of The determination of the characteristics of iron ore slurry under the conditions of ultrasonic control

Research paper thumbnail of Neural network simulation in running of acetic acid synthesis unit while start-up

Research paper thumbnail of Control of the process of vacuum gasoil catalytic cracking in terms of aerosol nanocatalysis technology

The article considers control of the process of catalytic cracking of vacuum gasoil. Authors sugg... more The article considers control of the process of catalytic cracking of vacuum gasoil. Authors suggest a block diagram of automatic control system of catalytic cracking reactor by aerosol nanocatalysis to stabilize oscillation frequency and temperature in the reactor.

Research paper thumbnail of Mathematical Models of Additional Measurement Errors of Control Means

Metrology and instruments, 2019

Studies have shown that under industrial conditions there is rarely a correction of the current m... more Studies have shown that under industrial conditions there is rarely a correction of the current measurement result when the influencing parameter deviates from the normalized value. The existing method of determining the additional measurement error is that in order to obtain the real value of the measurement result, the correction is calculated, which leads to the current value of indexes of control means. The correction value is determined by dividing the degree of the influencing parameter deviation by the normalized value of the additional error. This method of determining the correction is not accurate enough, since it does not take into account the nonlinear dependence of the additional measurement error on the change in the influencing parameter, as well as on the current value of the output signal of control means. To determine the real value of the measured parameter and the additional error, the method of integral-type functional is proposed. The essence of the method is i...

Research paper thumbnail of Principles and stages of creation of automatic control systems with a model of complex technological processes

Eastern-European Journal of Enterprise Technologies

The object of this study is an effective approach to designing automatic control systems with a m... more The object of this study is an effective approach to designing automatic control systems with a model of complex technological processes, which include interrelated and complementary stages from the formulation of the task to the implementation of the control system at the facility. It includes a set of measures, starting with the analysis of the process in its hardware design with the construction of an information and logical scheme to the development of all types of security and commissioning. The main problem in the implementation of a control system with a technological process model is the limited ranges of adequacy of mathematical models. Therefore, when changing the load on the unit, changing external and internal perturbations, it is necessary to constantly ensure the necessary level of adequacy of the models. It is proposed to use a combined model as a mathematical model of the control object, combining the advantages of analytical and experimental-statistical models. This...

Research paper thumbnail of The Study of the Dispersion and Phase Velocity of Love Waves

2022 IEEE 41st International Conference on Electronics and Nanotechnology (ELNANO)

Research paper thumbnail of Research of Features of Oxide Coatings Deposition by D–gun Spraying

Lecture notes in mechanical engineering, Jun 18, 2022

Research paper thumbnail of Influence of the Magnetic Field on Love Waves Propagation in the Solid Medium

2020 IEEE 40th International Conference on Electronics and Nanotechnology (ELNANO), 2020

Effects of the magnetic field cause additional transverse and longitudinal oscillations that are ... more Effects of the magnetic field cause additional transverse and longitudinal oscillations that are not inherent in the ordinary Love wave. The aim of this research is generalization of the approach to the influence of the two-component magnetic field on the surface waves in the conducting solid semi-space in case of the Love waves in the semi-space and the solid conducting layer on it. Analytical argumentation of the mechanism of transforming the Love waves in the conducting layer of the semi-space influenced by the magnetic field was proposed allowing to develop the method of determining density of the iron ore slurry and magnetic iron content in it. Practical significance implies the research results applied to designing means of ultrasonic control over density of the iron ore slurry and its magnetic iron content.

Research paper thumbnail of Design Calculation of Automatic Rotary Motion Electrohydraulic Drive for Technological Equipment

Lecture Notes in Mechanical Engineering, 2021

Research paper thumbnail of Application of Magnetic and Ultrasonic Methods for Determining Parameters of Ferromagnetic Components in Iron Ore Slurry Flows

Acta Mechanica et Automatica, 2021

The article considers the method for controlling the ferromagnetic component content in slurry fl... more The article considers the method for controlling the ferromagnetic component content in slurry flow by ultrasonic and magnetic measurements. One of the basic factors determining the efficiency of magnetic separators at iron ore concentration plants is the quality of distribution of the ground ore into the product containing the ferromagnetic component and the waste rock. Due to the fact that in most cases, magnetic separators extract minerals with strongly magnetic properties, it is essential to find the magnetic component content in the input ore and products of its distribution in order to improve control over the technological process. Currently, low accuracy and reliability make existing means of operative control over the ferromagnetic component content in the slurry flow inefficient. Density of slurry is one of the primary disturbing factors affecting the accuracy of measurements, and this fact determines the necessity of measuring this parameter while controlling the ferromag...

Research paper thumbnail of Design Calculation of Electrohydraulic Servo Drive for Technological Equipment

Advances in Design, Simulation and Manufacturing III, 2020

The engineering method for design calculation of electrohydraulic servo drive with throttle regul... more The engineering method for design calculation of electrohydraulic servo drive with throttle regulation is proposed. The method is adapted on drives of technological equipment, in particular, equipment for mechanical processing of materials. The engineering method allows determining the main parameters and choosing elements and devices of the drive, to predict its static and dynamic characteristics. As the input data are considered: maximum loading; maximum tracking speed without load; maximum tracking error (or allowable tracking error at maximum speed); piston stroke; reduced mass of moving parts. The method includes the following main stages: construction of the drive settlement scheme, choice of the working fluid and the nominal working pressure; calculation of the constructive parameters and choice of the hydraulic cylinder; choice of the electrohydraulic amplifier; definition of the feedback parameters, determining the drive quality factor and calculation the transfer coefficient of the electronic block; evaluation of the drive static characteristics, calculation of the speed and load characteristics; construction of the drive linear model, stability assessment; research of the drive dynamic characteristics and the control quality, drive correction. The example of the design calculation of the electrohydraulic servo drive for technological equipment is presented. For calculations used the MATLAB application package.

Research paper thumbnail of The Influence of the Characteristics Variations of the Concentrating Plant Control Object on the Identification Results Using the Hammerstein Model

Sustainable Development of Mountain Territories, 2021

As a result of the identification based on the Hammerstein model of objects of the first stage of... more As a result of the identification based on the Hammerstein model of objects of the first stage of iron ore magnetic separation, the adequacy of the model is obtained. All results of the testing of the developed identification algorithms show that the subsystem of identification of the automated process control systems of processing plants based on the Hammerstein hybrid model allows to carry out satisfactory identification of objects and, as a consequence, to improve the quality of technological processes. The study of the influence of the coefficient of various typical links on the results of identification using orthogonal parallel and parallel-recursive Hammerstein models showed that these models allow considering the differences in the properties of identifiable objects adequately.

Research paper thumbnail of Measurement of the ferromagnetic component content in the ore suspension solid phase

Ultrasonics, 2020

A method for determining the ferromagnetic component content in the ore suspension solid phase ha... more A method for determining the ferromagnetic component content in the ore suspension solid phase has been developed. The proposed method allows determining the volume fractions of the solid phase and the magnetic component in the pulp from the results of Love waves intensity measurements and the pulp magnetic permeability. It is not necessary to know the wave intensity at the output of the ultrasound source. The results of the attenuation coefficient calculation depending on the volume fraction of the solid phase in the pulp are presented. According to the chemical analysis, the comparative results of measurements ferromagnetic component content in the pulp are given.

Research paper thumbnail of Studying additional measurement errors from control tools using an integral functional method

Eastern-European Journal of Enterprise Technologies, 2019

Research paper thumbnail of Predictive Control of the Iron Ore Beneficiation Process Based on the Hammerstein Hybrid Model

Acta Mechanica et Automatica, 2019

Non-linear, dynamic, non-stationary properties characterize objects of the iron ore beneficiation... more Non-linear, dynamic, non-stationary properties characterize objects of the iron ore beneficiation line. Therefore, for their approximation, it is advisable to use models of the Hammerstein class. As a result of comparing the three models of Hammerstein: simple, parallel and recursive-parallel, it was shown that the best result for identifying the considered processes of magnetic beneficiation of iron ore by the minimum error criterion was obtained using the Hammerstein recursive-parallel model. Hence, it is recommended for the identification of beneficiation production objects.

Research paper thumbnail of Twice displaced, but unconquered: The experience of reviving a Ukrainian university during the war

Problems and Perspectives in Management

A new wave of relocation of universities from the war zone has resulted from the negative consequ... more A new wave of relocation of universities from the war zone has resulted from the negative consequences of the hostilities and the temporary occupation of the territories of Ukraine by the russian federation. The challenges of today have a multidirectional impact, especially on universities that have been displaced twice. The relocation of each university is a unique experience, and academic management is the object of modern scientific research. Therefore, the paper aims to highlight the experience of gaining resilience and developing the sustainability of Volodymyr Dahl East Ukrainian National University (hereinafter V. Dahl EUNU) during the evacuation in 2014 from the city of Luhansk to the town of Severodonetsk, and in 2022 along the entire movement path to the city of Kyiv. It is determined that the main resources are human and social capital, which allow not only counteractong the challenges of martial law, but also ensuring the restoration of the system and its further develop...

Research paper thumbnail of Comparison of Studies of Dangerous Cargo Flow Distribution Between Rail and Road Transport

TRANSBALTICA XI: Transportation Science and Technology, 2020

The article compares the results of different studies of dangerous cargo flow distribution betwee... more The article compares the results of different studies of dangerous cargo flow distribution between rail and road transport. The dependency has been examined by example of actual data that assesses the percentage ratio variation of transported dangerous cargo by rail and road transport when the total quantity of cargo changes by one percent. The results of this study have been compared to the results of expert survey on the issues of competitiveness of dangerous cargo transportation between rail and road transport.

Research paper thumbnail of Study of Field Testing on Car Body Vibrations of Moving Passenger Car with Wheel Flat

TRANSBALTICA XI: Transportation Science and Technology, 2020

The article analyze the methodology of experimental investigations of railway vehicles under real... more The article analyze the methodology of experimental investigations of railway vehicles under real operating conditions. The aim of the research is to determine the vertical and lateral accelerations of the carbody of passenger car with a wheel flat by running along the same track at different speeds. Statistical analysis of the obtained data was performed. Experimental results were evaluated using shock acceleration ratio and Sperling ride index was calculated. General conclusions are given.

Research paper thumbnail of Research of the automatic control system of belt conveyor on the technical basis of the industrial controller Schneider Electric

S u m m a r y . The results of the studies of complex system of automatic control of processes of... more S u m m a r y . The results of the studies of complex system of automatic control of processes of the transportation and the crushing of the ore been presented. The principles of control been based on the measurement of temperature field on the zone of the friction. The efficiency of the approach confirmed by the results of theoretical and experimental research of the control system based on industrial controllers Schneider Electric. K e y w o r d s . Industrial controllers, belt tension control, mathematical models of distributed parameters.

Research paper thumbnail of Some algorithms of computer algebra

The article describes one of the methods for computing determinants without using fractions propo... more The article describes one of the methods for computing determinants without using fractions proposed by Bareiss. This problem has a clear algorithmic character in nature and refers to the field of computer algebra. The implementation of this algorithm is proposed in the known Maxima system of symbolic computations. In addition, this method makes it possible to get enough convenient formula for the calculation of the matrix of unitriangular transformation of a quadratic form to a canonical one.

Research paper thumbnail of The determination of the characteristics of iron ore slurry under the conditions of ultrasonic control

Research paper thumbnail of Neural network simulation in running of acetic acid synthesis unit while start-up

Research paper thumbnail of Control of the process of vacuum gasoil catalytic cracking in terms of aerosol nanocatalysis technology

The article considers control of the process of catalytic cracking of vacuum gasoil. Authors sugg... more The article considers control of the process of catalytic cracking of vacuum gasoil. Authors suggest a block diagram of automatic control system of catalytic cracking reactor by aerosol nanocatalysis to stabilize oscillation frequency and temperature in the reactor.

Research paper thumbnail of Mathematical Models of Additional Measurement Errors of Control Means

Metrology and instruments, 2019

Studies have shown that under industrial conditions there is rarely a correction of the current m... more Studies have shown that under industrial conditions there is rarely a correction of the current measurement result when the influencing parameter deviates from the normalized value. The existing method of determining the additional measurement error is that in order to obtain the real value of the measurement result, the correction is calculated, which leads to the current value of indexes of control means. The correction value is determined by dividing the degree of the influencing parameter deviation by the normalized value of the additional error. This method of determining the correction is not accurate enough, since it does not take into account the nonlinear dependence of the additional measurement error on the change in the influencing parameter, as well as on the current value of the output signal of control means. To determine the real value of the measured parameter and the additional error, the method of integral-type functional is proposed. The essence of the method is i...

Research paper thumbnail of Principles and stages of creation of automatic control systems with a model of complex technological processes

Eastern-European Journal of Enterprise Technologies

The object of this study is an effective approach to designing automatic control systems with a m... more The object of this study is an effective approach to designing automatic control systems with a model of complex technological processes, which include interrelated and complementary stages from the formulation of the task to the implementation of the control system at the facility. It includes a set of measures, starting with the analysis of the process in its hardware design with the construction of an information and logical scheme to the development of all types of security and commissioning. The main problem in the implementation of a control system with a technological process model is the limited ranges of adequacy of mathematical models. Therefore, when changing the load on the unit, changing external and internal perturbations, it is necessary to constantly ensure the necessary level of adequacy of the models. It is proposed to use a combined model as a mathematical model of the control object, combining the advantages of analytical and experimental-statistical models. This...

Research paper thumbnail of The Study of the Dispersion and Phase Velocity of Love Waves

2022 IEEE 41st International Conference on Electronics and Nanotechnology (ELNANO)

Research paper thumbnail of Research of Features of Oxide Coatings Deposition by D–gun Spraying

Lecture notes in mechanical engineering, Jun 18, 2022

Research paper thumbnail of Influence of the Magnetic Field on Love Waves Propagation in the Solid Medium

2020 IEEE 40th International Conference on Electronics and Nanotechnology (ELNANO), 2020

Effects of the magnetic field cause additional transverse and longitudinal oscillations that are ... more Effects of the magnetic field cause additional transverse and longitudinal oscillations that are not inherent in the ordinary Love wave. The aim of this research is generalization of the approach to the influence of the two-component magnetic field on the surface waves in the conducting solid semi-space in case of the Love waves in the semi-space and the solid conducting layer on it. Analytical argumentation of the mechanism of transforming the Love waves in the conducting layer of the semi-space influenced by the magnetic field was proposed allowing to develop the method of determining density of the iron ore slurry and magnetic iron content in it. Practical significance implies the research results applied to designing means of ultrasonic control over density of the iron ore slurry and its magnetic iron content.

Research paper thumbnail of Design Calculation of Automatic Rotary Motion Electrohydraulic Drive for Technological Equipment

Lecture Notes in Mechanical Engineering, 2021

Research paper thumbnail of Application of Magnetic and Ultrasonic Methods for Determining Parameters of Ferromagnetic Components in Iron Ore Slurry Flows

Acta Mechanica et Automatica, 2021

The article considers the method for controlling the ferromagnetic component content in slurry fl... more The article considers the method for controlling the ferromagnetic component content in slurry flow by ultrasonic and magnetic measurements. One of the basic factors determining the efficiency of magnetic separators at iron ore concentration plants is the quality of distribution of the ground ore into the product containing the ferromagnetic component and the waste rock. Due to the fact that in most cases, magnetic separators extract minerals with strongly magnetic properties, it is essential to find the magnetic component content in the input ore and products of its distribution in order to improve control over the technological process. Currently, low accuracy and reliability make existing means of operative control over the ferromagnetic component content in the slurry flow inefficient. Density of slurry is one of the primary disturbing factors affecting the accuracy of measurements, and this fact determines the necessity of measuring this parameter while controlling the ferromag...

Research paper thumbnail of Design Calculation of Electrohydraulic Servo Drive for Technological Equipment

Advances in Design, Simulation and Manufacturing III, 2020

The engineering method for design calculation of electrohydraulic servo drive with throttle regul... more The engineering method for design calculation of electrohydraulic servo drive with throttle regulation is proposed. The method is adapted on drives of technological equipment, in particular, equipment for mechanical processing of materials. The engineering method allows determining the main parameters and choosing elements and devices of the drive, to predict its static and dynamic characteristics. As the input data are considered: maximum loading; maximum tracking speed without load; maximum tracking error (or allowable tracking error at maximum speed); piston stroke; reduced mass of moving parts. The method includes the following main stages: construction of the drive settlement scheme, choice of the working fluid and the nominal working pressure; calculation of the constructive parameters and choice of the hydraulic cylinder; choice of the electrohydraulic amplifier; definition of the feedback parameters, determining the drive quality factor and calculation the transfer coefficient of the electronic block; evaluation of the drive static characteristics, calculation of the speed and load characteristics; construction of the drive linear model, stability assessment; research of the drive dynamic characteristics and the control quality, drive correction. The example of the design calculation of the electrohydraulic servo drive for technological equipment is presented. For calculations used the MATLAB application package.

Research paper thumbnail of The Influence of the Characteristics Variations of the Concentrating Plant Control Object on the Identification Results Using the Hammerstein Model

Sustainable Development of Mountain Territories, 2021

As a result of the identification based on the Hammerstein model of objects of the first stage of... more As a result of the identification based on the Hammerstein model of objects of the first stage of iron ore magnetic separation, the adequacy of the model is obtained. All results of the testing of the developed identification algorithms show that the subsystem of identification of the automated process control systems of processing plants based on the Hammerstein hybrid model allows to carry out satisfactory identification of objects and, as a consequence, to improve the quality of technological processes. The study of the influence of the coefficient of various typical links on the results of identification using orthogonal parallel and parallel-recursive Hammerstein models showed that these models allow considering the differences in the properties of identifiable objects adequately.

Research paper thumbnail of Measurement of the ferromagnetic component content in the ore suspension solid phase

Ultrasonics, 2020

A method for determining the ferromagnetic component content in the ore suspension solid phase ha... more A method for determining the ferromagnetic component content in the ore suspension solid phase has been developed. The proposed method allows determining the volume fractions of the solid phase and the magnetic component in the pulp from the results of Love waves intensity measurements and the pulp magnetic permeability. It is not necessary to know the wave intensity at the output of the ultrasound source. The results of the attenuation coefficient calculation depending on the volume fraction of the solid phase in the pulp are presented. According to the chemical analysis, the comparative results of measurements ferromagnetic component content in the pulp are given.

Research paper thumbnail of Studying additional measurement errors from control tools using an integral functional method

Eastern-European Journal of Enterprise Technologies, 2019

Research paper thumbnail of Predictive Control of the Iron Ore Beneficiation Process Based on the Hammerstein Hybrid Model

Acta Mechanica et Automatica, 2019

Non-linear, dynamic, non-stationary properties characterize objects of the iron ore beneficiation... more Non-linear, dynamic, non-stationary properties characterize objects of the iron ore beneficiation line. Therefore, for their approximation, it is advisable to use models of the Hammerstein class. As a result of comparing the three models of Hammerstein: simple, parallel and recursive-parallel, it was shown that the best result for identifying the considered processes of magnetic beneficiation of iron ore by the minimum error criterion was obtained using the Hammerstein recursive-parallel model. Hence, it is recommended for the identification of beneficiation production objects.