EuroBrake 2021 Technical Programme最新文献

{"title":"Structured Light 3D Sensor for Fast and High Precision Surface Dynamics Measurements","authors":"G. Ostermeyer, chen fang, Guido Lehne-Wandrey, Malte Sandgaard, A. Vogel, Jacek Kijanski, Thomas Hillner, Fabian Repetz","doi":"10.46720/2224108eb2021-stp-006","DOIUrl":"https://doi.org/10.46720/2224108eb2021-stp-006","url":null,"abstract":"Friction tests under controlled conditions are crucial for the understanding of the boundary layer dynamics in technical brake systems. The dynamics of the friction interface characterize the braking performance. In order to evaluate and monitor the dynamics of the friction interface, detailed insights into the friction behavior is obtained by high precision tribotesters under laboratory conditions. Especially in the low sliding speed range, specialized machines such as the Variable Velocity Tribotester (VVT) make it possible to mimic real world phenomena under controlled conditions, e.g. creep groan or COF in low temperatures. This paper presents the wenglor sensoric 3D sensor ShapeDrive MLAS201 for measuring the pad surface between friction applications at VVT. With this device, quasi in-situ measurements with high speed and precision of the pad’s surface are attained. The 3D sensor consists of a light engine which projects several patterns onto the pad surface and a high resolution camera which can record these patterns again. The topography and intensity information of the pad surface would be stored in a point cloud file with high precision of 12 megapixels. Such information can be used to analyze the surface properties such as roughness and height. With further algorithms it is also possible to observe the change of the entire topography and in further way to determine the wear volume and analyze the contact situations.","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"178 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124405831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance of Non-segmented and Segmented Railway Brake Discs - Temperatures, Wear and Fatigue Investigated by Field Experiments and Simulations","authors":"Mandeep Singh Walia, Bjarke Raaby, Gaël Le Gigan, T. Vernersson, R. Lundén","doi":"10.46720/3701665eb2021-stp-016","DOIUrl":"https://doi.org/10.46720/3701665eb2021-stp-016","url":null,"abstract":"The maintenance procedure for railway brake discs is highly complicated, time-consuming and costly. Firstly, the entire wheelset is separated from the wagon and then the bearings and the wheels are separated from the axle followed by the brake discs. For this reason, brake discs are preferably changed at the same time as the wheels. This procedure involves a risk of damaging the wheels and the axle during removal and reinstallation. The axle might develop scuffs or scratches, leading to replacement of the entire axle. Such incidents cause increased life cycle costs of these wagons. A segmented brake disc can provide improved maintainability, since they can be exchanged with the wheelset still under the wagon. Thus, there is no need for dismounting the wheels from the axle. Only the external friction ring is replaced, effectively reusing the brake disc hub mounted on the axle. Another important factor for the life cycle costs of these wagons is the wear of brake discs and brake pads. Highly wear resistant brake discs and brake pads will be favourable.Studies already exists where brake disc temperatures and wear are studied via laboratory experiments and simulations. However, studies are rare that compare different types of brake discs and pads by field experiments and simulations. In the present study, the performance of two different types of brake discs and brake pads used on Swedish postal wagons is investigated through a combination of field experiments and numerical simulations. Thus, one traditional solid grey cast iron brake disc with organic composite brake pads and one segmented NiCrMo alloyed cast iron brake disc with sintered brake pads are compared. The focus is on disc and pad temperatures and wear at revenue traffic and on calculated thermomechanical fatigue performance of the two brake disc types. Field tests were carried out for a postal wagon equipped with two different friction pairs. One consists of an enhanced grey cast iron material “segmented” brake disc (friction rings built from five identical sectors) with sintered friction material. The other consists of a standard grey cast iron “reference” disc with organic composite friction material as originally used on this wagon. During revenue service with speeds up to 160 km/h, temperatures for brake discs and brake pads were recorded along with train braking data in the form of train speed, friction forces and pneumatic brake pressures. A compact thermocamera setup was used to record temperature distributions over disc friction surfaces. Wear of discs and pads were measured intermittently by use of a laser scanning device and precision scales, respectively. Simulation models for predicting brake disc and pad temperatures are established. Heat partitioning factors pertaining to the disc and pad interface and convection cooling models are calibrated using data acquired for the two studied friction pairs. Finally, the thermomechanical behaviour and the fatigue of the two brake disc","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130767936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lab-Scale Anodization of Prototype Brake Calipers","authors":"Federico Bertasi, Marco Bandiera, A. Mancini, Ariana Pavesi, A. Bonfanti, M. Bestetti","doi":"10.46720/3846714eb2021-stp-012","DOIUrl":"https://doi.org/10.46720/3846714eb2021-stp-012","url":null,"abstract":"Anodization plays a pivotal role in improving the corrosion resistance of Aluminum-Silicon alloys (AlSix) used in the production of brake calipers.[1] However, the presence of eutectic Silicon particles within the Al matrix can reduce the oxide layer growing rate, leading to inhomogeneous and porous coatings. Following this, tailored current/potential anodization waveforms have been developed, in order to overcome the presence of Silicon, thus obtaining anodic layers with enhanced morphological and corrosion-resistance features.[2][3] In this scenario, a fervent lab-scale R&D activity has been carried out regarding the optimization of pulsed anodization in terms of current density and frequency of the used square wave, obtaining: 1) coated AlSix specimens (30cm2) showing a superior corrosion resistance; and 2) a set of refined anodization parameters to be used to treat AlSix –based materials.[4] Unfortunately, anodization of a prototype caliper, using the obtained optimized waveforms, is not straightforward and appears particularly more challenging with respect to the lab-scale treatment of small specimens. Indeed, the presence of: a) non-uniform Silicon distribution (machined vs. non-machined regions); and b) shielded areas and/or sharp edges; can strongly influence the oxide growth, leading to inhomogeneous coatings and a morphology-dependent corrosion resistance. As a further step toward the implementation of the optimized parameters in an anodization pilot plant, an electrochemical bath is designed, aiming at: 1) anodize a single brake caliper; and 2) scale up the anodization parameters from specimens to caliper treatment. The manuscript will discuss the so-obtained anodized caliper in terms of oxide layer: a) morphology; b) wettability; and c) corrosion resistance. The effect of optimized vs. non-optimized parameters will be discussed as well. Results allow to outline the path for an advanced anodization process, that will briefly lead to obtain AlSix brake calipers with an extended corrosion resistance. References: [1] Bandiera, M., Bonfanti, A., Mauri, A., Mancini, A., Bestetti, M., Bertasi, F., “Corrosion Phenomena in Braking Systems”, CORROSION/20, Manuscript no. C2020-14550, 2020. [2] Bandiera, M., Bonfanti, A., Bestetti, M., Bertasi, F., “Anodization: Recent Advancements on Corrosion Protection of Brake Calipers”, SAE Technical Paper, Manuscript no. 2020-01-1626, 2020. [3] Fratila-Apachitei, L. E., J. Duszczyk, and L. Katgerman. \"AlSi (Cu) anodic oxide layers formed in H2SO4 at low temperature using different current waveforms\", Surface and Coatings Technology, 165.3, pp. 232-240, 2003. [4] Bandiera, M., Mancini, A., Pavesi, A., Bonfanti, A., Bestetti, M., Bertasi, F., “Optimized Pulsed Anodization for Corrosion Protection of Aluminum Silicon Alloys”, CORROSION/21, Manuscript no. C2021-16431, 2021. (under review).","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122499030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Disc Brake Pad Interface Pressure Distributions Using FBG Sensors","authors":"Zicheng Wang, Steve James, M. Tirovic","doi":"10.46720/4746216eb2021-stp-021","DOIUrl":"https://doi.org/10.46720/4746216eb2021-stp-021","url":null,"abstract":"Research Background and Objectives: Validation of modelling results and experimental investigations of processes taking place at disc brake friction surfaces is very difficult due to the high interface pressures and temperatures, complex component interactions, rotating motion and wear, as well as limited space. The installed sensors may also alter component characteristics and interface properties by adding mass or disrupting friction surface. Although some modern optical techniques can provide insights into dynamic component behaviour, typically only visible surfaces can be observed. Following these challenges, the authors have used Fibre Bragg Grating sensors (FBGs) in order to experimentally determine interface pressure distributions at brake pad/disc interface, pad strains and deflections and research subsequent influence on brake performance and NVH (noise, vibration and harshness) characteristics, in particular squeal and judder. The ultimate aim is to improve brake designs in terms of higher and more stable friction characteristics. Methodology: The disc brake analysed uses a four-pot fixed (opposed pistons) caliper which has been modified to allow for independent hydraulic inputs in the leading and trailing pairs of hydraulic chambers. The authors have designed and manufactured a suitable experimental system, with two-channel control hydraulic system, allowing for an independent variation of the hydraulic pressure, hence the position of the centre of pressure at pad/disc interfaces can be easily altered. Fibre Bragg Grating sensors (FBGs) were installed on both sides of brake pads (friction and backplate surfaces) in order to measure friction material and backplate strain levels, and to compare them with Finite Element (FE), Tekscan and Digital Image Correlation (DIC) results. In such a manner, a much more detailed information has been obtained about the interface pressure distributions as well as pad and calliper strains. Results: The experimental steps have been divided into 3 steps: static analysis, quasi-dynamic analysis (torque application with no disc rotation) and fully dynamic analysis. By gradually increasing the complexity of loading, theoretical and experimental approaches can be suitably compared, and most effective solutions established. Based on these 3 steps, the processes taking place at disc/pad friction surfaces have been much better understood. Furthermore, several design parameters have been varied in order to investigate their influence on brake friction performance and NVH characteristics. Limitations: So far the tests were limited to the static and quasi-dynamic (applied torque with no disc rotation) conditions, with further work concentrating on fully dynamic braking conditions, to account for disc rotation and thermal effects. Conclusion: The FBG sensors demonstrated suitability for such an application, giving an instant information about the pad strains, interface pressure distributions and the position of the c","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133881821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a Small-scale Test Bench for Investigating the Tribology and Emission Behaviour of Novel Brake Friction Couples","authors":"F. Limmer, D. Barton, C. Gilkeson, P. Brooks, S. Kosarieh","doi":"10.46720/6023901eb2021-stp-002","DOIUrl":"https://doi.org/10.46720/6023901eb2021-stp-002","url":null,"abstract":"The brake industry is currently on the search for lighter, corrosion-resistant and more eco-friendly brake systems. Apart from health and environmental issues, the main drivers for this development are the changing load profiles arising from the megatrends of electrification and autonomous driving. As the brake disc and brake pad together represent a tribological system, both components must be adjusted in order to achieve optimal functionality. Testing of brake friction couples, however, is usually a very costly, energy and time-consuming process, that only allows for a very limited range of material concepts to be considered. This is where testing friction materials on a small-scale level has great advantages because much time and money can potentially be saved in sample generation, testing and post-test analysis compared with full-scale testing. A novel small-scale test bench has been developed at the University of Leeds which aims to screen friction materials under realistic braking conditions. The foundation of the setup is the Bruker UMT TriboLab tribometer operating in a modified pin-on-disc type configuration. Popular full-scale cycles such as the WLTP based real-world driving cycle have been implemented to replicate current everyday driving scenarios as well as custom cycles that aim to simulate possible future load profiles. A full enclosure around the friction couple has been designed using CFD to allow for controlled airflow and subsequent wear debris capture and analysis. The wear particles generated during braking operation are sampled under isokinetic conditions using the well-known Dekati ELPI+ instrument. The paper will report on the scaling approach used to design the test bench and the conversion of the WLTP based real-world driving cycle to a non-inertial system. Details of the CFD analysis as well as preliminary test results will also be presented.","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125207206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introduction to Shift2Rail","authors":"C. Borghini","doi":"10.46720/7334620eb2021-mfm-005","DOIUrl":"https://doi.org/10.46720/7334620eb2021-mfm-005","url":null,"abstract":"Mr. Carlo Borghini, Executive Director of the European Shift2Rail Joint Undertaking, introduces the Shift2Rail R&I Programme, with particular focus on the evolution of automation in the European railway systems in order to maximize the performance of the current infrastructure in terms of capacity, lifecycle cost reductions and punctuality. In this respect, railway automation and digitalization rely on the performance and contributions of critical subsystems, where the braking systems has a major role. The R&I work started with a bottom up technological approach in S2R has evolved during the years with the introduction of a system integrated approach, to ensure that all critical elements deliver together a functional performance that will contribute to deliver sustainable mobility, with rail playing a major role.","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"264 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122932435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crack Detection in Friction Material of Brake Pads","authors":"J. J. Bustos, A. van den Bossche","doi":"10.46720/3753068eb2021-stp-014","DOIUrl":"https://doi.org/10.46720/3753068eb2021-stp-014","url":null,"abstract":"Vehicles today may bear little resemblance to their predecessors but one element remains largely unchanged: the disk brake is still the most commonly used braking system for automotive vehicles. Brake pad production is big business and competition has driven the development of new types of friction materials – materials whose properties need careful characterization and this is where impulse excitation comes in. Analysis of the resonant frequencies following impulse excitation is a well-established quality assurance tool for brake pads. It even has its own standard: SAE J2598. The push to develop more environmentally and biologically friendly brake-pad materials has led to the introduction of new friction materials. Some of these materials may however be more prone to cracking either in the production process or during use, thus a simple method is needed to identify cracks in brake pads.","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129069496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Modelling of Composite Brake Pad Operational Deflection Shapes","authors":"M. Ravanbod","doi":"10.46720/7143269eb2021-stp-008","DOIUrl":"https://doi.org/10.46720/7143269eb2021-stp-008","url":null,"abstract":"This project outlines the effect of changing Young’s modulus, Poisson’s ratios and shear modulus on the pad natural frequencies. It aims to improve the understanding of the influence of friction material properties on the pad natural frequencies, to observe how the natural frequencies can change, with the changes in the properties of the composite brake pad friction material. In addition, two different brake pad models (Pad-A and Pad-B) were designed, using CATIA V5 software to study whether different pad aspect ratios can affect the influence of friction material properties on the natural frequencies. This study utilizes the free-free analysis on the brake pads, to investigate the natural frequencies, and the mode shapes of the first four modes, using ABAQUS software. Also, an experimental test (Tap testing) on Pad-A was carried out to verify the accuracy of the numerical analysis. The research has demonstrated that the maximum variation between the numerical and the experimental results is 5.1%, which is acceptable. Thus, the numerical analysis provided reasonable results.Furthermore, the factorial analysis was applied on the obtained natural frequencies for each pad, to find out the material properties that have the main effect on the natural frequencies, and the relationship between each property and the natural frequency, using MINITAB software. The results indicated that increasing Young’s modulus in the horizontal plane can increase the values of natural frequencies, while a decrease in Young’s modulus in the vertical plane, Poisson’s ratios, and shear modulus in all planes can increase the values of the natural frequencies. Therefore, the research deduced that Young’s modulus, and Poisson’s ratios in the horizontal plane must be taken into account, when choosing a suitable orthotropic friction material for brake pads. This relationship between the friction material properties and the natural frequency is independent of pad aspect ratios, and can be concluded for all types of pads. The natural frequency plays a significant role in triggering brake squeal. Brake squeal can occur if the pad natural frequency is coupled with the disc frequency. Therefore, determining how altering friction material properties affects the pad natural frequency, can help to propose an appropriate friction material for the pad, in order to have the pad natural frequency, which is not close to the disc frequency in the frequency range, where the brake noise occurs.","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128407069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adhesion-related Wear Dust Transport","authors":"G. Ostermeyer, Cheng Fang, Felix Rickhoff","doi":"10.46720/6577111eb2021-stp-007","DOIUrl":"https://doi.org/10.46720/6577111eb2021-stp-007","url":null,"abstract":"The frictional behavior of a tribological contact is the result of complex interactions between two bodies. In the case of tribological high-load contacts, such as those found in brakes, wear and the associated wear particles play a particularly important role. In the last two decades, a number of papers have been written on this subject, which explain the highly complex dynamics of the friction coefficient, among other things, with the self-organization structures of the wear material in the tribocontact. Here, particle concentrations, so-called patches, form, which act like additional contact areas in the boundary layer. Since they change dynamically, the friction performance shows similar dynamic structures. But the ejection of wear particles is also the current focus of research. The emissions also exhibit dynamic signatures. This work wants to present the further developed measurement technique as well as first approaches to describe the wear particle transport in the boundary layer by experiment and simulation","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122112787","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Particle Simulation and Metrological Validation of Brake Emission Dynamics on a Pin-on-Disc Tribotester","authors":"S. Brandt, Malte Sandgaard, G. Ostermeyer, S. Gramstat, F. Stebner, Conrad Weigmann, A. Kwade, C. Schilde","doi":"10.46720/7443155eb2021-stp-013","DOIUrl":"https://doi.org/10.46720/7443155eb2021-stp-013","url":null,"abstract":"The increasing degree of electrification as well as the optimization of particle based exhaust emissions, which is already being driven forward due to legislation, will direct the focus of fine dust considerations in automotive technology to non-exhaust emissions. In contrast to exhaust emissions, there are currently only a few vehicle-related limit values or uniform standards in measurement technology and the measurement procedure. The area of non-exhaust emissions includes tire abrasion, the turbulence of organic and inorganic road particles, and brake wear. Since, in addition to the material component, the particle size also has a significant influence on the health hazard of the material, particulate emissions from brakes are often directly related to health effects. In comparison to previous measurements, which have mostly been carried out in enclosed and clinical environments, the dynamics of the fine dust emitted from the brake will be investigated using a fully automated tribometer and used as a possibility to validate a DEM simulation. Besides the pure measurement of the emitted particle size distributions during the brake application, conclusions on the agglomeration behaviour of the emission particles in the environment shall be drawn. The aim is to predict the environmental impact and the potential danger of the particles to humans due to the particle size released into the environment. The pin-disc contact between brake pad and brake disc serves as the emission source. A coupled CFD-DEM simulation environment was set up to simulate particle dynamics. Based on a rotating brake disc model, the flow-relevant components of the test bench environment were implemented into the simulation setup. The area around the actual brake contact as well as the environment at the tribometer should be considered. For the metrological validation of the simulation, a swarm of calibrated low-cost sensors as well as a scattered light based particle size measuring device will be set up around the tribometer","PeriodicalId":315146,"journal":{"name":"EuroBrake 2021 Technical Programme","volume":"226 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123719396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}