Pub Date : 2023-11-06DOI: 10.24425/BPAS.2018.125925
T. Poggio, Q. Liao
Bull. Pol. Ac.: Tech. 66(6) 2018 Abstract. The landscape of the empirical risk of overparametrized deep convolutional neural networks (DCNNs) is characterized with a mix of theory and experiments. In part A we show the existence of a large number of global minimizers with zero empirical error (modulo inconsistent equations). The argument which relies on the use of Bezout theorem is rigorous when the RELUs are replaced by a polynomial nonlinearity. We show with simulations that the corresponding polynomial network is indistinguishable from the RELU network. According to Bezout theorem, the global minimizers are degenerate unlike the local minima which in general should be non-degenerate. Further we experimentally analyzed and visualized the landscape of empirical risk of DCNNs on CIFAR-10 dataset. Based on above theoretical and experimental observations, we propose a simple model of the landscape of empirical risk. In part B, we characterize the optimization properties of stochastic gradient descent applied to deep networks. The main claim here consists of theoretical and experimental evidence for the following property of SGD: SGD concentrates in probability – like the classical Langevin equation – on large volume, ”flat” minima, selecting with high probability degenerate minimizers which are typically global minimizers.
{"title":"Theory II: Deep learning and optimization","authors":"T. Poggio, Q. Liao","doi":"10.24425/BPAS.2018.125925","DOIUrl":"https://doi.org/10.24425/BPAS.2018.125925","url":null,"abstract":"Bull. Pol. Ac.: Tech. 66(6) 2018 Abstract. The landscape of the empirical risk of overparametrized deep convolutional neural networks (DCNNs) is characterized with a mix of theory and experiments. In part A we show the existence of a large number of global minimizers with zero empirical error (modulo inconsistent equations). The argument which relies on the use of Bezout theorem is rigorous when the RELUs are replaced by a polynomial nonlinearity. We show with simulations that the corresponding polynomial network is indistinguishable from the RELU network. According to Bezout theorem, the global minimizers are degenerate unlike the local minima which in general should be non-degenerate. Further we experimentally analyzed and visualized the landscape of empirical risk of DCNNs on CIFAR-10 dataset. Based on above theoretical and experimental observations, we propose a simple model of the landscape of empirical risk. In part B, we characterize the optimization properties of stochastic gradient descent applied to deep networks. The main claim here consists of theoretical and experimental evidence for the following property of SGD: SGD concentrates in probability – like the classical Langevin equation – on large volume, ”flat” minima, selecting with high probability degenerate minimizers which are typically global minimizers.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"9 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81102459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.24425/BPASTS.2020.134643
M. Jacyna, R. Jachimowski, E. Szczepański, M. Izdebski
The paper presents the issue of container handling processes at a railroad intermodal terminal. The main purpose of this paper is the assessment of the handling equipment utilization and the associated energy consumption. The authors analyze how the road vehicle availability at the moment specified in the containers loading schedule influences the total handling equipment operation time as well as the necessary number of handling equipment. It is assumed that vehicles planned for loading of import containers may be late for loading, which causes some interruptions in the loading schedule. Such interruptions are identified with the necessity to handle the next container for which the road vehicle is already waiting, which influences the handling equipment utilization and, finally, energy consumption. The general mathematical model of the problem developed in the FlexSim simulation software was presented. Based on the simulation research, it pointed out that proper road vehicles loading sequencing can significantly reduce handling equipment operation time, and thus energy consumption, costs, and CO2 emissions. The literature analysis presented in the paper indicates that most of the research in the field of intermodal transport is focused on operations optimization in container ports. There are differences between two types of intermodal terminals in operation procedures and rules. That is why the authors decided to undertake the problem of road vehicle sequencing including their random availability and its influence on handling device operation time, which has not been considered in the literature so far.
{"title":"Road vehicle sequencing problem in a railroad intermodal terminal – simulation research","authors":"M. Jacyna, R. Jachimowski, E. Szczepański, M. Izdebski","doi":"10.24425/BPASTS.2020.134643","DOIUrl":"https://doi.org/10.24425/BPASTS.2020.134643","url":null,"abstract":"The paper presents the issue of container handling processes at a railroad intermodal terminal. The main purpose of this paper is the assessment of the handling equipment utilization and the associated energy consumption. The authors analyze how the road vehicle availability at the moment specified in the containers loading schedule influences the total handling equipment operation time as well as the necessary number of handling equipment. It is assumed that vehicles planned for loading of import containers may be late for loading, which causes some interruptions in the loading schedule. Such interruptions are identified with the necessity to handle the next container for which the road vehicle is already waiting, which influences the handling equipment utilization and, finally, energy consumption. The general mathematical model of the problem developed in the FlexSim simulation software was presented. Based on the simulation research, it pointed out that proper road vehicles loading sequencing can significantly reduce handling equipment operation time, and thus energy consumption, costs, and CO2 emissions. The literature analysis presented in the paper indicates that most of the research in the field of intermodal transport is focused on operations optimization in container ports. There are differences between two types of intermodal terminals in operation procedures and rules. That is why the authors decided to undertake the problem of road vehicle sequencing including their random availability and its influence on handling device operation time, which has not been considered in the literature so far.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"85 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75844581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.24425/BPASTS.2020.134176
W. Jefimowski, A. Nikitenko, Z. Drążek, M. Wieczorek
The paper proposes to apply an algorithm for predicting the minimum level of the state of charge (SoC) of stationary supercapacitor energy storage system operating in a DC traction substation, and for changing it over time. This is done to insure maximum energy recovery for trains while braking. The model of a supercapacitor energy storage system, its algorithms of operation and prediction of the minimum state of charge are described in detail; the main formulae, graphs and results of simulation are also provided. It is proposed to divide the SoC curve into equal periods of time during which the minimum states of charge remain constant. To predict the SoC level for the subsequent period, the learning algorithm based on the neural network could be used. Then, the minimum SoC could be based on two basic types of data: the first one is the time profile of the energy storage load during the previous period with the constant minimum SoC retained, while the second one relies on the trains’ locations and speed values in the previous period. It is proved that the use of variable minimum SoC ensures an increase of the energy volume recovered by approximately 10%. Optimum architecture and activation function of the neural network are also found.
{"title":"Stationary supercapacitor energy storage operation algorithm based on neural network learning system","authors":"W. Jefimowski, A. Nikitenko, Z. Drążek, M. Wieczorek","doi":"10.24425/BPASTS.2020.134176","DOIUrl":"https://doi.org/10.24425/BPASTS.2020.134176","url":null,"abstract":"The paper proposes to apply an algorithm for predicting the minimum level of the state of charge (SoC) of stationary supercapacitor energy storage system operating in a DC traction substation, and for changing it over time. This is done to insure maximum energy recovery for trains while braking. The model of a supercapacitor energy storage system, its algorithms of operation and prediction of the minimum state of charge are described in detail; the main formulae, graphs and results of simulation are also provided. It is proposed to divide the SoC curve into equal periods of time during which the minimum states of charge remain constant. To predict the SoC level for the subsequent period, the learning algorithm based on the neural network could be used. Then, the minimum SoC could be based on two basic types of data: the first one is the time profile of the energy storage load during the previous period with the constant minimum SoC retained, while the second one relies on the trains’ locations and speed values in the previous period. It is proved that the use of variable minimum SoC ensures an increase of the energy volume recovered by approximately 10%. Optimum architecture and activation function of the neural network are also found.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76072366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.24425/BPAS.2019.128607
P. Siemaszko, Z. Meyer
This paper expands the M-K curve theory with examples of the most commonly mentioned pile-soil mechanics behaviours in the literature and their corresponding κ2 variations. A brief introduction shows the history of the Meyer-Kowalow theory and its basic assumptions. This is followed by the relationship between in situ investigation CPT results, with parameters C1, C2, Ct used to approximate the load-settlement curve according to the M-K theory. The Meyer-Kowalow curve satisfies asymptotic behaviour for small loads, where linear theory applies, and for limit loads, when pile displacement is out of control. Essential in the description are constant parameters C, which refer to the aggregated Winklers modulus, Ngr limit loads and k, which is crucial for static load test results. For this reason, the authors sought to calculate the κ value based upon soil mechanics principles. This article shows methods for checking statistical mathematical calculations, published earlier by Meyer using CPT investigations. It presents real case calculations and directions for future planned research.
{"title":"Static load test curve analysis based on soil field investigations","authors":"P. Siemaszko, Z. Meyer","doi":"10.24425/BPAS.2019.128607","DOIUrl":"https://doi.org/10.24425/BPAS.2019.128607","url":null,"abstract":"This paper expands the M-K curve theory with examples of the most commonly mentioned pile-soil mechanics behaviours in the literature and their corresponding κ2 variations. A brief introduction shows the history of the Meyer-Kowalow theory and its basic assumptions. This is followed by the relationship between in situ investigation CPT results, with parameters C1, C2, Ct used to approximate the load-settlement curve according to the M-K theory. The Meyer-Kowalow curve satisfies asymptotic behaviour for small loads, where linear theory applies, and for limit loads, when pile displacement is out of control. Essential in the description are constant parameters C, which refer to the aggregated Winklers modulus, Ngr limit loads and k, which is crucial for static load test results. For this reason, the authors sought to calculate the κ value based upon soil mechanics principles. This article shows methods for checking statistical mathematical calculations, published earlier by Meyer using CPT investigations. It presents real case calculations and directions for future planned research.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"29 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74937686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.24425/BPASTS.2020.131850
H. Zarzycki, W. Dobrosielski, Ł. Apiecionek, T. Vince
The article introduces a new proposal of a defuzzif ication method, which can be implemented in fuzzy controllers. The f irst chapter refers to the origin of fuzzy sets. Next, a modern development based on this theory is presented in the form of ordered fuzzy numbers (OFN). The most important characteristics of ordered fuzzy numbers are also presented. In the following chapter, details about the defuzzif ication process are given as part of the fuzzy controller model. Then a new method of defuzzif ication is presented. The method is named center of circles intersection (CCI). The authors compare this method with a similar geometric solution: triangular expanding (TE) and geometric mean (GM). Also, the results are compared with other methods such as center of gravity (COG), f irst of maxima (FOM) and last of maxima (LOM). The analysis shows that the proposed solution works correctly and provides results for traditional fuzzy numbers as well as directed fuzzy numbers. The last chapter contains a summary, in which more detailed conclusions are provided and further directions of research are indicated.
{"title":"Center of circles intersection, a new defuzzification method for fuzzy numbers","authors":"H. Zarzycki, W. Dobrosielski, Ł. Apiecionek, T. Vince","doi":"10.24425/BPASTS.2020.131850","DOIUrl":"https://doi.org/10.24425/BPASTS.2020.131850","url":null,"abstract":"The article introduces a new proposal of a defuzzif ication method, which can be implemented in fuzzy controllers. The f irst chapter refers to the origin of fuzzy sets. Next, a modern development based on this theory is presented in the form of ordered fuzzy numbers (OFN). The most important characteristics of ordered fuzzy numbers are also presented. In the following chapter, details about the defuzzif ication process are given as part of the fuzzy controller model. Then a new method of defuzzif ication is presented. The method is named center of circles intersection (CCI). The authors compare this method with a similar geometric solution: triangular expanding (TE) and geometric mean (GM). Also, the results are compared with other methods such as center of gravity (COG), f irst of maxima (FOM) and last of maxima (LOM). The analysis shows that the proposed solution works correctly and provides results for traditional fuzzy numbers as well as directed fuzzy numbers. The last chapter contains a summary, in which more detailed conclusions are provided and further directions of research are indicated.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"20 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88314421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.24425/BPASTS.2020.133373
T. Maciołek, M. Lewandowski, A. Szeląg, M. Steczek
Short-term contact losses between a pantograph and a contact wire are not included in the standards nor are they taken into account in evaluating pantograph-contact wire interaction. These contact losses, however, accelerate wear and tear as well as disturb operation of vehicles’ drive systems. The article presents the effects of short-term contact breaks as well as an analysis of impact of contact breakages on a vehicle’s current at 3 kV DC power supply. Results of voltage and current oscillations measured in real conditions when pantograph of a DC driven chopper vehicle was running under isolators were presented. Then a simulation model of a vehicles with ac motors and voltage inverters was derived to undertake simulation experiments verifying operation of such a vehicle in condition similar to those measured in real condition.
{"title":"Influence of contact gaps on the conditions of vehicles supply and wear and tear of catenary wires in a 3 kV DC traction system","authors":"T. Maciołek, M. Lewandowski, A. Szeląg, M. Steczek","doi":"10.24425/BPASTS.2020.133373","DOIUrl":"https://doi.org/10.24425/BPASTS.2020.133373","url":null,"abstract":"Short-term contact losses between a pantograph and a contact wire are not included in the standards nor are they taken into account in evaluating pantograph-contact wire interaction. These contact losses, however, accelerate wear and tear as well as disturb operation of vehicles’ drive systems. The article presents the effects of short-term contact breaks as well as an analysis of impact of contact breakages on a vehicle’s current at 3 kV DC power supply. Results of voltage and current oscillations measured in real conditions when pantograph of a DC driven chopper vehicle was running under isolators were presented. Then a simulation model of a vehicles with ac motors and voltage inverters was derived to undertake simulation experiments verifying operation of such a vehicle in condition similar to those measured in real condition.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"689 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78700776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.24425/BPASTS.2020.134660
M. Skowron, M. Wolkiewicz, G. Tarchała
In this paper deep neural networks are proposed to diagnose inter-turn short-circuits of induction motor stator windings operating under the Direct Field Oriented Control method. A convolutional neural network (CNN), trained with a Stochastic Gradient Descent with Momentum method is used. This kind of deep-trained neural network allows to significantly accelerate the diagnostic process compared to the traditional methods based on the Fast Fourier Transform as well as it does not require stationary operating conditions. To assess the effectiveness of the applied CNN-based detectors, the tests were carried out for variable load conditions and different values of the supply voltage frequency. Experimental results of the proposed induction motor fault detection system are presented and discussed.
{"title":"Stator winding fault diagnosis of induction motor operating under the field-oriented control with convolutional neural networks","authors":"M. Skowron, M. Wolkiewicz, G. Tarchała","doi":"10.24425/BPASTS.2020.134660","DOIUrl":"https://doi.org/10.24425/BPASTS.2020.134660","url":null,"abstract":"In this paper deep neural networks are proposed to diagnose inter-turn short-circuits of induction motor stator windings operating under the Direct Field Oriented Control method. A convolutional neural network (CNN), trained with a Stochastic Gradient Descent with Momentum method is used. This kind of deep-trained neural network allows to significantly accelerate the diagnostic process compared to the traditional methods based on the Fast Fourier Transform as well as it does not require stationary operating conditions. To assess the effectiveness of the applied CNN-based detectors, the tests were carried out for variable load conditions and different values of the supply voltage frequency. Experimental results of the proposed induction motor fault detection system are presented and discussed.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"112 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74672960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.24425/BPASTS.2020.134649
Ł. Niewiara, T. Tarczewski, L. Grzesiak
In this paper an application of extended Kalman filter (EKF) for estimation and attenuation of periodic disturbance in permanent magnet synchronous motor (PMSM) drive is investigated. Most types of disturbances present into PMSM drive were discussed and described. The mathematical model of the plant is presented. Detailed information about the design process of the disturbance estimator was introduced. A state feedback controller (SFC) with feedforward realizes the regulation and disturbance compensation. The theoretical analysis was supported by experimental tests on the laboratory stand. Both timeand frequency-domain analysis of the estimation results and angular velocity were performed. A significant reduction of velocity ripple has been achieved.
{"title":"Application of extended Kalman filter for estimation of periodic disturbance and velocity ripple reduction in PMSM drive","authors":"Ł. Niewiara, T. Tarczewski, L. Grzesiak","doi":"10.24425/BPASTS.2020.134649","DOIUrl":"https://doi.org/10.24425/BPASTS.2020.134649","url":null,"abstract":"In this paper an application of extended Kalman filter (EKF) for estimation and attenuation of periodic disturbance in permanent magnet synchronous motor (PMSM) drive is investigated. Most types of disturbances present into PMSM drive were discussed and described. The mathematical model of the plant is presented. Detailed information about the design process of the disturbance estimator was introduced. A state feedback controller (SFC) with feedforward realizes the regulation and disturbance compensation. The theoretical analysis was supported by experimental tests on the laboratory stand. Both timeand frequency-domain analysis of the estimation results and angular velocity were performed. A significant reduction of velocity ripple has been achieved.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"55 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74893494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.24425/BPASTS.2021.136719
Roman Regulski, D. Czarnecka-Komorowska, C. Jędryczka, D. Sędziak, D. Rybarczyk, K. Netter, Mariusz Stanisław Barański, M. Barczewski
Many researchers in the developed countries have been intensively seeking effective methods of plastic recycling over the past years. Those techniques are necessary to protect our natural environment and save non-renewable resources. This paper presents the concept of an electrostatic separator designed as a test bench dedicated to the separation of mixed plastic waste from the automotive industry. According to the current policy of the European Union on the recycling process of the automotive industry, all these waste materials must be recycled further for re-entering into the life cycle (according to the circular economy). In this paper, the proposed concept and design of the test bench were offered the feasibility to conduct research and technological tests of the electrostatic separation process of mixed plastics. The designed test bench facilitated assessing the impact of positions of high-voltage electrodes, the value and polarity of the high voltage, the variable speed of feeders and drums, and also triboelectrification parameters (like time and intensity) on the process, among others. A specialized computer vision system has been proposed and developed to enable quick and reliable evaluation of the impact of process parameters on the efficiency of electrostatic separation. The preliminary results of the conducted tests indicated that the proposed innovative design of the research stand ensures high research potential, thanks to the high accuracy of mixed plastics in a short time. The results showed the significant impact of the corona electrode position and the value of the applied voltage on the separation process effectiveness. It can be concluded that the results confirmed the ability to determine optimally the values of the studied parameters, in terms of plastic separation effectiveness. This study showed that this concept of an electrostatic separator designed as a test bench dedicated for separation of mixed plastic waste can be widely applied in the recycling plastic industry.
{"title":"Automated test bench for research on electrostatic separation in plastic recycling application","authors":"Roman Regulski, D. Czarnecka-Komorowska, C. Jędryczka, D. Sędziak, D. Rybarczyk, K. Netter, Mariusz Stanisław Barański, M. Barczewski","doi":"10.24425/BPASTS.2021.136719","DOIUrl":"https://doi.org/10.24425/BPASTS.2021.136719","url":null,"abstract":"Many researchers in the developed countries have been intensively seeking effective methods of plastic recycling over the past years. Those techniques are necessary to protect our natural environment and save non-renewable resources. This paper presents the concept of an electrostatic separator designed as a test bench dedicated to the separation of mixed plastic waste from the automotive industry. According to the current policy of the European Union on the recycling process of the automotive industry, all these waste materials must be recycled further for re-entering into the life cycle (according to the circular economy). In this paper, the proposed concept and design of the test bench were offered the feasibility to conduct research and technological tests of the electrostatic separation process of mixed plastics. The designed test bench facilitated assessing the impact of positions of high-voltage electrodes, the value and polarity of the high voltage, the variable speed of feeders and drums, and also triboelectrification parameters (like time and intensity) on the process, among others. A specialized computer vision system has been proposed and developed to enable quick and reliable evaluation of the impact of process parameters on the efficiency of electrostatic separation. The preliminary results of the conducted tests indicated that the proposed innovative design of the research stand ensures high research potential, thanks to the high accuracy of mixed plastics in a short time. The results showed the significant impact of the corona electrode position and the value of the applied voltage on the separation process effectiveness. It can be concluded that the results confirmed the ability to determine optimally the values of the studied parameters, in terms of plastic separation effectiveness. This study showed that this concept of an electrostatic separator designed as a test bench dedicated for separation of mixed plastic waste can be widely applied in the recycling plastic industry.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"11 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79514977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-06DOI: 10.24425/BPASTS.2019.129662
D. Băilă, S. Tonoiu
. The aeronautical industry is a sector constantly looking for new materials and equipment because of its tendency to expand quickly. The Ti6Al4V titanium alloy is used frequently in the aeronautic, aerospace, automobile, chemical and medical industry because it presents high strength combined with low density ( approximately 4.5 g / cm 3 ) , good creep resistance ( up to 550°C ) , excellent corrosion resistance, high flexibility, good fatigue and biocompatibility. As a result of these properties, this titanium alloy is considered an excellent material for manufacturing structural parts in the aircraft industry for modern aeronautic structures, especially for airframes and aero-engines. But its use is also problematic because the Ti6Al4V titanium alloy manifests hydrogen embrittlement, by means of hydrides precipitation in the metal. The Ti6Al4V alloy becomes brittle and fractures because of hydrogen diffusion into metal and because titanium hydrides appear and create pres-sure from within the metal, thus generating corrosion. Because of titanium hydrides, the titanium alloy suffers from reduced ductility, tensile strength and toughness, which can result in fractures of aeronautical parts. This poses a very serious problem for aircrafts. In this paper, rapid hydrogen embrittlement is presented along with XRD, SEM and TEM analysis. Its goal is to detect the presence of titanium hydrides and to spot the initial cracks in the metallic material.
． 航空工业是一个不断寻找新材料和设备的行业，因为它有迅速扩张的趋势。Ti6Al4V钛合金由于具有高强度、低密度(约4.5 g / cm3)、良好的抗蠕变性能(高达550°C)、优异的耐腐蚀性、高柔韧性、良好的抗疲劳性和生物相容性，在航空、航天、汽车、化工和医疗行业中得到了广泛的应用。由于这些特性，这种钛合金被认为是制造现代航空结构的飞机工业结构件的优良材料，特别是用于机身和航空发动机。但它的使用也存在问题，因为Ti6Al4V钛合金通过金属中的氢化物沉淀表现出氢脆。由于氢扩散到金属中，并且钛氢化物出现并从金属内部产生压力，从而产生腐蚀，Ti6Al4V合金变得脆性和断裂。由于氢化钛的存在，钛合金的延展性、抗拉强度和韧性都会降低，这可能导致航空部件断裂。这对飞机来说是一个非常严重的问题。采用XRD、SEM、TEM等分析方法对其进行了快速氢脆表征。它的目标是探测氢化钛的存在，并发现金属材料中最初的裂缝。
{"title":"Hydrides precipitation in Ti6Al4V titanium alloy used for airframe manufacturing","authors":"D. Băilă, S. Tonoiu","doi":"10.24425/BPASTS.2019.129662","DOIUrl":"https://doi.org/10.24425/BPASTS.2019.129662","url":null,"abstract":". The aeronautical industry is a sector constantly looking for new materials and equipment because of its tendency to expand quickly. The Ti6Al4V titanium alloy is used frequently in the aeronautic, aerospace, automobile, chemical and medical industry because it presents high strength combined with low density ( approximately 4.5 g / cm 3 ) , good creep resistance ( up to 550°C ) , excellent corrosion resistance, high flexibility, good fatigue and biocompatibility. As a result of these properties, this titanium alloy is considered an excellent material for manufacturing structural parts in the aircraft industry for modern aeronautic structures, especially for airframes and aero-engines. But its use is also problematic because the Ti6Al4V titanium alloy manifests hydrogen embrittlement, by means of hydrides precipitation in the metal. The Ti6Al4V alloy becomes brittle and fractures because of hydrogen diffusion into metal and because titanium hydrides appear and create pres-sure from within the metal, thus generating corrosion. Because of titanium hydrides, the titanium alloy suffers from reduced ductility, tensile strength and toughness, which can result in fractures of aeronautical parts. This poses a very serious problem for aircrafts. In this paper, rapid hydrogen embrittlement is presented along with XRD, SEM and TEM analysis. Its goal is to detect the presence of titanium hydrides and to spot the initial cracks in the metallic material.","PeriodicalId":55299,"journal":{"name":"Bulletin of the Polish Academy of Sciences-Technical Sciences","volume":"435 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83627415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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