One fundamental difficulty in understanding the physics of the off-road traction and in predicting vehicle performance is the variability of the terrain profile and soil parameters. These operating conditions are uniquely defined at a given spatial location and a given time. It is not practically feasible, however, to measure them at a sufficiently large number of points to be able to accurately represent the terrain in models. This renders traditional analysis tools insufficient when dealing with rough deformable terrain. We employ stochastic analysis to capture the uncertain nature of this running support and the corresponding vehicle response. From a finite number of observations the terrain profile and soil properties can be modeled as random processes, with the actual operating conditions viewed as a particular realization of these processes. Soil parameters vary substantially from one type of soil to another. Moreover, for the same soil type, the parameters change with environmental conditions difficult to predict, for example the moisture content. Such uncertain soil parameters are modeled in this study as uniform or normal distributed random variables.
{"title":"Stochastic Modeling of Terrain Profiles and Soil Parameters","authors":"C. Sandu, Adrian Sandu, Lin Li","doi":"10.4271/2005-01-3559","DOIUrl":"https://doi.org/10.4271/2005-01-3559","url":null,"abstract":"One fundamental difficulty in understanding the physics of the off-road traction and in predicting vehicle performance is the variability of the terrain profile and soil parameters. These operating conditions are uniquely defined at a given spatial location and a given time. It is not practically feasible, however, to measure them at a sufficiently large number of points to be able to accurately represent the terrain in models. This renders traditional analysis tools insufficient when dealing with rough deformable terrain. We employ stochastic analysis to capture the uncertain nature of this running support and the corresponding vehicle response. From a finite number of observations the terrain profile and soil properties can be modeled as random processes, with the actual operating conditions viewed as a particular realization of these processes. Soil parameters vary substantially from one type of soil to another. Moreover, for the same soil type, the parameters change with environmental conditions difficult to predict, for example the moisture content. Such uncertain soil parameters are modeled in this study as uniform or normal distributed random variables.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"1 1","pages":"211-220"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87737801","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}
Brad Grinstead, A. Koschan, D. Page, A. Gribok, M. Abidi
Three-dimensional models of real world terrain have application in a variety of tasks, but digitizing a large environment poses constraints on the design of a 3D scanning system. We have developed a Mobile Scanning System that works within these constraints to quickly digitize large-scale real world environments. We utilize a mobile platform to move our sensors past the scene to be digitized – fusing the data from cm-level accuracy laser range scanners, positioning and orientation instruments, and high-resolution video cameras – to provide the mobility and speed required to quickly and accurately model the target scene.
{"title":"Vehicle-borne Scanning for Detailed 3D Terrain Model Generation","authors":"Brad Grinstead, A. Koschan, D. Page, A. Gribok, M. Abidi","doi":"10.4271/2005-01-3557","DOIUrl":"https://doi.org/10.4271/2005-01-3557","url":null,"abstract":"Three-dimensional models of real world terrain have application in a variety of tasks, but digitizing a large environment poses constraints on the design of a 3D scanning system. We have developed a Mobile Scanning System that works within these constraints to quickly digitize large-scale real world environments. We utilize a mobile platform to move our sensors past the scene to be digitized – fusing the data from cm-level accuracy laser range scanners, positioning and orientation instruments, and high-resolution video cameras – to provide the mobility and speed required to quickly and accurately model the target scene.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"25 1","pages":"196-204"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81718908","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}
This paper describes the implementation effort behind adding a pair of suspension links between the axle and frame of a light truck with a Hotchkiss-type suspension. These links, referred to as anti-windup bars (or traction bars), were introduced into an existing system to improve NVH performance; however, doing so required modifications to maintain other vehicle attributes, including vehicle safety and durability life. The authors address the management of these attributes and related design decisions for the components involved, focusing on the conflicting requirements involved. Physical vehicle testing, using design revisions recommended by Finite Element (FE) simulations, was performed to confirm component performance and related system behavior. Test results suggested improvements to the FE models that were required to more closely approximate the vehicle's behavior. Several of these FE model improvements and component design iterations were implemented simultaneously, resulting in effective anti-windup bar and frame structure design revisions. These design revisions improved the system's ability to manage the energy inputs to the system during vehicle durability and crash testing.
{"title":"Managing System Effects of Traction Bars Implemented on a Hotchkiss Suspension","authors":"Ian Zook, D. Kirby, Nagaraj Siddegowda","doi":"10.4271/2005-01-3624","DOIUrl":"https://doi.org/10.4271/2005-01-3624","url":null,"abstract":"This paper describes the implementation effort behind adding a pair of suspension links between the axle and frame of a light truck with a Hotchkiss-type suspension. These links, referred to as anti-windup bars (or traction bars), were introduced into an existing system to improve NVH performance; however, doing so required modifications to maintain other vehicle attributes, including vehicle safety and durability life. The authors address the management of these attributes and related design decisions for the components involved, focusing on the conflicting requirements involved. Physical vehicle testing, using design revisions recommended by Finite Element (FE) simulations, was performed to confirm component performance and related system behavior. Test results suggested improvements to the FE models that were required to more closely approximate the vehicle's behavior. Several of these FE model improvements and component design iterations were implemented simultaneously, resulting in effective anti-windup bar and frame structure design revisions. These design revisions improved the system's ability to manage the energy inputs to the system during vehicle durability and crash testing.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"11 1","pages":"278-284"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82603132","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}
Using a simulation model, this study intends to provide a preliminary evaluation of whether semiactive dampers are beneficial to improving ride and handling in class 8 trucks. One of the great challenges in designing a truck suspension system is maintaining a good balance between vehicle ride and handling. The suspension components are often designed with great care for handling, while maintaining good comfort. For Class 8 trucks, the vehicle comfort is also greatly affected by the cab and seat suspensions. Dampers for passive suspensions are tuned "optimally," using various metrics that the ride engineer may consider, for the condition in which the truck operates most frequently. In recent years, the popularity of semiactive dampers in passenger vehicles has prompted the possibility of considering them for class 8 trucks. In this study, the vehicle safety versus ride comfort trade-off is studied for a certain class of suspensions with semiactive fuzzy control. The proposed semiactive fuzzy control is based on the control policies that are commonly known as skyhook and groundhook. After describing the mathematical details of the proposed semiactive fuzzy control, it is applied to a roll-plane model of a heavy truck in order to compare its performance with conventional passive suspensions. The results of this study show that although semiactive suspensions with fuzzy logic control can improve vehicle roll, they could result in larger peak accelerations and a harsher ride.
{"title":"Semiactive Fuzzy Logic Control for Heavy Truck Primary Suspensions: Is it Effective?","authors":"M. Ahmadian","doi":"10.4271/2005-01-3542","DOIUrl":"https://doi.org/10.4271/2005-01-3542","url":null,"abstract":"Using a simulation model, this study intends to provide a preliminary evaluation of whether semiactive dampers are beneficial to improving ride and handling in class 8 trucks. One of the great challenges in designing a truck suspension system is maintaining a good balance between vehicle ride and handling. The suspension components are often designed with great care for handling, while maintaining good comfort. For Class 8 trucks, the vehicle comfort is also greatly affected by the cab and seat suspensions. Dampers for passive suspensions are tuned \"optimally,\" using various metrics that the ride engineer may consider, for the condition in which the truck operates most frequently. In recent years, the popularity of semiactive dampers in passenger vehicles has prompted the possibility of considering them for class 8 trucks. In this study, the vehicle safety versus ride comfort trade-off is studied for a certain class of suspensions with semiactive fuzzy control. The proposed semiactive fuzzy control is based on the control policies that are commonly known as skyhook and groundhook. After describing the mathematical details of the proposed semiactive fuzzy control, it is applied to a roll-plane model of a heavy truck in order to compare its performance with conventional passive suspensions. The results of this study show that although semiactive suspensions with fuzzy logic control can improve vehicle roll, they could result in larger peak accelerations and a harsher ride.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"11 1","pages":"157-165"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75540270","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}
J. G. Howe, Dongchan Lee, J. Chrstos, O. Balling, T. Myers, R. Allen, D. Gorsich, Alexander A. Reid
The U.S. Army uses the root mean square and power spectral density of elevation to characterize road/terrain (off-road) roughness for durability. This paper describes research aimed toward improving these metrics. The focus is on taking previously developed metrics and applying them to mathematically generated terrains to determine how each metric discerns the relative roughness of the terrains from a vehicle durability perspective. Multiple terrains for each roughness level were evaluated to determine the variability for each terrain rating metric. One method currently under consideration is running a relatively simple, yet vehicle class specific, model over a given terrain and using predicted vehicle response(s) to classify or characterize the terrain.
{"title":"Further Analysis of Potential Road/Terrain Characterization Rating Metrics","authors":"J. G. Howe, Dongchan Lee, J. Chrstos, O. Balling, T. Myers, R. Allen, D. Gorsich, Alexander A. Reid","doi":"10.4271/2005-01-3562","DOIUrl":"https://doi.org/10.4271/2005-01-3562","url":null,"abstract":"The U.S. Army uses the root mean square and power spectral density of elevation to characterize road/terrain (off-road) roughness for durability. This paper describes research aimed toward improving these metrics. The focus is on taking previously developed metrics and applying them to mathematically generated terrains to determine how each metric discerns the relative roughness of the terrains from a vehicle durability perspective. Multiple terrains for each roughness level were evaluated to determine the variability for each terrain rating metric. One method currently under consideration is running a relatively simple, yet vehicle class specific, model over a given terrain and using predicted vehicle response(s) to classify or characterize the terrain.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"11 1","pages":"228-241"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83436721","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}
Ilhan Bayraktar, D. Landman, W. Cary, R. Wood, J. Flamm, C. Hunter
Aerodynamic drag, lift, and side forces have a profound influence on fuel efficiency, vehicle speed, stability, acceleration and performance. All of these areas benefit from drag reduction and changing the lift force in favor of the operating conditions. The present study simulates the external flow field around a heavy truck with three prototype add-on drag reduction devices using a computational method. The model and the method are selected to be three dimensional and time-dependent. The Reynolds-averaged Navier Stokes equations are solved using a finite volume method. The Renormalization Group (RNG)ek- model was elected for closure of the turbulent quantities. The run cases were chosen so that the influence of each drag reduction device could be established using a regression model from a Design of Experiments (DOEX) derived test matrix.
{"title":"An assessment of drag reduction devices for heavy trucks using design of experiments and computational fluid dynamics","authors":"Ilhan Bayraktar, D. Landman, W. Cary, R. Wood, J. Flamm, C. Hunter","doi":"10.4271/2005-01-3526","DOIUrl":"https://doi.org/10.4271/2005-01-3526","url":null,"abstract":"Aerodynamic drag, lift, and side forces have a profound influence on fuel efficiency, vehicle speed, stability, acceleration and performance. All of these areas benefit from drag reduction and changing the lift force in favor of the operating conditions. The present study simulates the external flow field around a heavy truck with three prototype add-on drag reduction devices using a computational method. The model and the method are selected to be three dimensional and time-dependent. The Reynolds-averaged Navier Stokes equations are solved using a finite volume method. The Renormalization Group (RNG)ek- model was elected for closure of the turbulent quantities. The run cases were chosen so that the influence of each drag reduction device could be established using a regression model from a Design of Experiments (DOEX) derived test matrix.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"102 1","pages":"135-146"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73456901","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}
Hong Lin, Mick Deis, Thomas A. Woodard, D. Combs, Robert R. Binoniemi
A nano-composite high strength (NCHS) steel was tested and evaluated in this work. Monotonic tension, strain controlled fatigue and fracture toughness tests were conducted at ambient temperature. Chemical composition, microstructure and fractography analysis were also performed. The NCHS steel showed excellent combination of high strength, high ductility and high fracture toughness with relatively low alloy content, compared with a S7 tool steel. Fatigue performance of the NCHS steel was also better than that of S7 tool steel. With the exceptional combination of high strength and high fracture toughness, the nano-composite high strength steel may have potential applications in gears, shafts, tools and dies where high fatigue performance, shock load resistance, wear and corrosion resistance is required.
{"title":"Cyclic Deformation, Fatigue and Fracture Toughness of a Nano-Composite High Strength Steel","authors":"Hong Lin, Mick Deis, Thomas A. Woodard, D. Combs, Robert R. Binoniemi","doi":"10.4271/2005-01-3629","DOIUrl":"https://doi.org/10.4271/2005-01-3629","url":null,"abstract":"A nano-composite high strength (NCHS) steel was tested and evaluated in this work. Monotonic tension, strain controlled fatigue and fracture toughness tests were conducted at ambient temperature. Chemical composition, microstructure and fractography analysis were also performed. The NCHS steel showed excellent combination of high strength, high ductility and high fracture toughness with relatively low alloy content, compared with a S7 tool steel. Fatigue performance of the NCHS steel was also better than that of S7 tool steel. With the exceptional combination of high strength and high fracture toughness, the nano-composite high strength steel may have potential applications in gears, shafts, tools and dies where high fatigue performance, shock load resistance, wear and corrosion resistance is required.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"34 1","pages":"285-297"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81234923","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}
In this paper finite element model of porous materials is used to improve the acoustical behavior of vehicle sound absorbers. The equation of wave propagation in the porous materials with rigid frame is presented after explaining the physical properties of these materials. The finite element formulation of governing equation and boundary conditions is obtained based on Galerkin method. Simulation results are compared with the corresponding results of the other validated papers and also verified by analytical results. Finally, effects of physical and geometrical parameters on the acoustical behavior of absorbers are studied. In addition, the influence of an air gap on the back of the material and also multilayer absorbers are investigated. It is shown that the acoustical behavior of these materials, particularly in the low frequency range, can be improved.
{"title":"Optimization of Acoustical Behavior of Sound Absorptions Based on Finite Element Modeling","authors":"A. Ohadi, M. Moghaddami","doi":"10.4271/2005-01-3580","DOIUrl":"https://doi.org/10.4271/2005-01-3580","url":null,"abstract":"In this paper finite element model of porous materials is used to improve the acoustical behavior of vehicle sound absorbers. The equation of wave propagation in the porous materials with rigid frame is presented after explaining the physical properties of these materials. The finite element formulation of governing equation and boundary conditions is obtained based on Galerkin method. Simulation results are compared with the corresponding results of the other validated papers and also verified by analytical results. Finally, effects of physical and geometrical parameters on the acoustical behavior of absorbers are studied. In addition, the influence of an air gap on the back of the material and also multilayer absorbers are investigated. It is shown that the acoustical behavior of these materials, particularly in the low frequency range, can be improved.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"23 1","pages":"246-254"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80916694","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}
Dual clutch based transmissions (DCT) have been developed for passenger vehicles in Europe. Compared to a single clutch based transmission (SCT), DCT eliminates torque interrupts during gear-shifting so that the vehicles can run as smooth as one using an automatic transmission (AT). Traditionally AT needs to use torque converters to transmit engine torque to drivelines. However, a torque converter is complicated and expensive, and offers lower driveline efficiency than SCT and DCT. DCT technology is a cost-effective avenue to achieve smooth shifting while taking advantage of the some beneficial features of both AT and SCT. This paper presents the results of an analysis of the application of DCT on medium duty (MD) trucks. First, we set up a 6-speed DCT with two groups of three gear ratios in correspondence to two ceramic dry clutches. Clutch dampers are included in the DCT model. For simplicity but without loss of generality, the synchronizers are not included for this study. Then, based on this DCT model, a complete powertrain for a MD truck is modeled from engine to wheels. The grade, rolling resistance and air resistances are considered in the model as well. A speed based shifting strategy is adopted for this simulation study. Finally, we run the DCT based model to show both transmission and vehicle dynamics. For comparison purposes, an SCT based vehicle model is built too with the same 6-speed ratios for DCT. The simulation results show that DCT can make smoother shifting than SCT and avoid engine flaring. Tentative conclusions will be presented in the final section.
{"title":"Simulation Study of Dual Clutch Transmission for Medium Duty Truck Applications","authors":"Xubin Song, Jason Liu, Daniel G. Smedley","doi":"10.4271/2005-01-3590","DOIUrl":"https://doi.org/10.4271/2005-01-3590","url":null,"abstract":"Dual clutch based transmissions (DCT) have been developed for passenger vehicles in Europe. Compared to a single clutch based transmission (SCT), DCT eliminates torque interrupts during gear-shifting so that the vehicles can run as smooth as one using an automatic transmission (AT). Traditionally AT needs to use torque converters to transmit engine torque to drivelines. However, a torque converter is complicated and expensive, and offers lower driveline efficiency than SCT and DCT. DCT technology is a cost-effective avenue to achieve smooth shifting while taking advantage of the some beneficial features of both AT and SCT. This paper presents the results of an analysis of the application of DCT on medium duty (MD) trucks. First, we set up a 6-speed DCT with two groups of three gear ratios in correspondence to two ceramic dry clutches. Clutch dampers are included in the DCT model. For simplicity but without loss of generality, the synchronizers are not included for this study. Then, based on this DCT model, a complete powertrain for a MD truck is modeled from engine to wheels. The grade, rolling resistance and air resistances are considered in the model as well. A speed based shifting strategy is adopted for this simulation study. Finally, we run the DCT based model to show both transmission and vehicle dynamics. For comparison purposes, an SCT based vehicle model is built too with the same 6-speed ratios for DCT. The simulation results show that DCT can make smoother shifting than SCT and avoid engine flaring. Tentative conclusions will be presented in the final section.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"177 1","pages":"264-270"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74077783","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}
A. Cetin, Banu Sinanoglu, Serdar Gungor, A. Kanbolat, M. Adli
In this study, a compliant control strategy is developed, which makes the application of position based control strategies practicable for electric power assisted steering systems. In order to do this, an additional virtual degree of freedom is added to the system, which is stimulated by the torque exerted on the steering wheel by the driver and the pinion position. The electro-actuator modeled on the second pinion of the steering gear is then commanded to position the pinion to the virtual system position using a traditional position control strategy. Thus, a compliance behavior is established that can be varied depending on the vehicle states and environmental conditions to improve the vehicle dynamics and safety of the passenger.
{"title":"Compliant Control of Electric Power Assisted Steering Systems","authors":"A. Cetin, Banu Sinanoglu, Serdar Gungor, A. Kanbolat, M. Adli","doi":"10.4271/2005-01-3535","DOIUrl":"https://doi.org/10.4271/2005-01-3535","url":null,"abstract":"In this study, a compliant control strategy is developed, which makes the application of position based control strategies practicable for electric power assisted steering systems. In order to do this, an additional virtual degree of freedom is added to the system, which is stimulated by the torque exerted on the steering wheel by the driver and the pinion position. The electro-actuator modeled on the second pinion of the steering gear is then commanded to position the pinion to the virtual system position using a traditional position control strategy. Thus, a compliance behavior is established that can be varied depending on the vehicle states and environmental conditions to improve the vehicle dynamics and safety of the passenger.","PeriodicalId":21404,"journal":{"name":"SAE transactions","volume":"48 1","pages":"147-156"},"PeriodicalIF":0.0,"publicationDate":"2005-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74741145","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}
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