The present paper is devoted to the issue of what effect the axial load (compressive or tensile) has on the eigenfrequencies of a heterogeneous pinned-pinned beam with an intermediate roller support (called a PrsP beam). This problem is a three point boundary value problem (eigenvalue problem) associated with homogeneous boundary conditions. If the Green functions of the three point boundary value problem (BVP) are known the eigenvalue problem that provide the eigenfrequencies for the beam loaded axially can be transformed into an eigenvalue problem governed by a homogeneous Fredholm integral equation. The later eigenvalue problems can be reduced to an algebraic eigenvalue problem which then can be solved numerically by using an effective solution algorithm which is based on the boundary element method.
{"title":"Vibration of an axially loaded heterogeneous pinned-pinned beam with an intermediate roller support","authors":"L. Kiss, G. Szeidl, Messaudi Abderrazek","doi":"10.32973/jcam.2021.007","DOIUrl":"https://doi.org/10.32973/jcam.2021.007","url":null,"abstract":"The present paper is devoted to the issue of what effect the axial load (compressive or tensile) has on the eigenfrequencies of a heterogeneous pinned-pinned beam with an intermediate roller support (called a PrsP beam). This problem is a three point boundary value problem (eigenvalue problem) associated with homogeneous boundary conditions. If the Green functions of the three point boundary value problem (BVP) are known the eigenvalue problem that provide the eigenfrequencies for the beam loaded axially can be transformed into an eigenvalue problem governed by a homogeneous Fredholm integral equation. The later eigenvalue problems can be reduced to an algebraic eigenvalue problem which then can be solved numerically by using an effective solution algorithm which is based on the boundary element method.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"36 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80565769","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}
The application of cellular structural materials provide new light-weight capabilities in many engineering fields. But the microstructure significantly influences the strength, the fatigue and fracture behavior as well as the life span of a structure made from cellular materials. The current paper illustrates the general idea how to take into account the cellular microstructure in the stress and strain analysis. The detailed geometry, including all discontinuities in the microstructure is available, for instance from measurements provided by the computed tomography (CT). The proposed simulation methodology is a combination of the finite element method (FEM) and the finite cell method (FCM). The FCM approach is applied in regions where discontinuities occur, avoiding a body-fitted mesh. As basis of the FEM-FCM coupling the commercial FEA package Abaqus is used. The theoretical background and the overall simulation workflow along with specific implementation details are discussed. Finally, academic benchmark problems are used to verify the developed coupling method.
{"title":"Simulation of cellular structures with a coupled FEM-FCM approach based on CT data","authors":"U. Gabbert, M. Würkner","doi":"10.32973/jcam.2021.004","DOIUrl":"https://doi.org/10.32973/jcam.2021.004","url":null,"abstract":"The application of cellular structural materials provide new light-weight capabilities in many engineering fields. But the microstructure significantly influences the strength, the fatigue and fracture behavior as well as the life span of a structure made from cellular materials. The current paper illustrates the general idea how to take into account the cellular microstructure in the stress and strain analysis. The detailed geometry, including all discontinuities in the microstructure is available, for instance from measurements provided by the computed tomography (CT). The proposed simulation methodology is a combination of the finite element method (FEM) and the finite cell method (FCM). The FCM approach is applied in regions where discontinuities occur, avoiding a body-fitted mesh. As basis of the FEM-FCM coupling the commercial FEA package Abaqus is used. The theoretical background and the overall simulation workflow along with specific implementation details are discussed. Finally, academic benchmark problems are used to verify the developed coupling method.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"37 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73587377","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 deals with the determination of the displacements and stresses in a curved cantilever beam. The considered curved beam has circular centerline and the thickness of its cross section depends on the circumferential coordinate. The kinematics of Euler-Bernoulli beam theory are used. The curved elastic beam is fixed at one end and on the other end is subjected to concentrated moment and force; three different loading cases are considered. The paper gives analytical solutions for radial and circumferential displacements and cross-sectional rotation and circumferential stresses. The presented examples can be used as benchmark for the other types of solutions as given in this paper.
{"title":"Deformation of a cantilever curved beam with variable cross section","authors":"István Escedi, A. Baksa","doi":"10.32973/jcam.2021.002","DOIUrl":"https://doi.org/10.32973/jcam.2021.002","url":null,"abstract":"This paper deals with the determination of the displacements and stresses in a curved cantilever beam. The considered curved beam has circular centerline and the thickness of its cross section depends on the circumferential coordinate. The kinematics of Euler-Bernoulli beam theory are used. The curved elastic beam is fixed at one end and on the other end is subjected to concentrated moment and force; three different loading cases are considered. The paper gives analytical solutions for radial and circumferential displacements and cross-sectional rotation and circumferential stresses. The presented examples can be used as benchmark for the other types of solutions as given in this paper.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"1 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82995361","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}
Operator splitting is a powerful method for the numerical investigation of complex time-dependent models, where the stationary (elliptic) part consists of a sum of several structurally simpler sub-operators. As an alternative to the classical splitting methods, a new splitting scheme is proposed here, the Average Method with sequential splitting. In this method, a decomposition of the original problem is sought in terms of commuting matrices. Wedemonstrate that third-order accuracy can be achieved with the Average Method. The computational performance of the method is investigated, yielding run times 1-2 orders of magnitude faster than traditional methods.
{"title":"The average method is much better than average","authors":"Lívia Boda, I. Faragó, T. Kalmár-Nagy","doi":"10.32973/jcam.2021.003","DOIUrl":"https://doi.org/10.32973/jcam.2021.003","url":null,"abstract":"Operator splitting is a powerful method for the numerical investigation of complex time-dependent models, where the stationary (elliptic) part consists of a sum of several structurally simpler sub-operators. As an alternative to the classical splitting methods, a new splitting scheme is proposed here, the Average Method with sequential splitting. In this method, a decomposition of the original problem is sought in terms of commuting matrices. Wedemonstrate that third-order accuracy can be achieved with the Average Method. The computational performance of the method is investigated, yielding run times 1-2 orders of magnitude faster than traditional methods.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"7 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79763904","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}
Numerous studies and textbooks deal with the steady-state thermal conduction of radially nonhomogeneous circular cylinder. In contrast, there are relatively few studies on the thermal conduction problems of conical solid bodies. This study is intended as a modest contribution to the solution of thermal conductance problems of nonhomogeneous conical bodies. A one-dimensional steady-state heat conduction in nonhomogeneous conical body is considered. The thermal conductivity of the hollow conical body in a suitable chosen spherical coordinate system depends on the polar angle but is independent of the radial coordinate and azimuthal angle coordinate. A functionally graded type of material inhomogeneity is considered. All results of the paper are based on Fourier’s theory of heat conduction in solid bodies.
{"title":"A steady-state heat conduction problem of a nonhomogeneous conical body","authors":"I. Ecsedi, A. Baksa","doi":"10.32973/jcam.2021.006","DOIUrl":"https://doi.org/10.32973/jcam.2021.006","url":null,"abstract":"Numerous studies and textbooks deal with the steady-state thermal conduction of radially nonhomogeneous circular cylinder. In contrast, there are relatively few studies on the thermal conduction problems of conical solid bodies. This study is intended as a modest contribution to the solution of thermal conductance problems of nonhomogeneous conical bodies. A one-dimensional steady-state heat conduction in nonhomogeneous conical body is considered. The thermal conductivity of the hollow conical body in a suitable chosen spherical coordinate system depends on the polar angle but is independent of the radial coordinate and azimuthal angle coordinate. A functionally graded type of material inhomogeneity is considered. All results of the paper are based on Fourier’s theory of heat conduction in solid bodies.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"77 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88120937","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, a nonlinear vibrational and rotational analysis of microbeams in nanobiomaterials using Galerkin Decomposition (GDM) and Differential Transform Methods (DTM) is presented. The dependency of cell migration and growth on nanoscaffold porosity and pore size architecture in tissue regeneration is governed by a dynamic model for the nonlinear vibration and rotation of the microbeams of nanobiomaterials and represented by a set of nonlinear partial differential equations. The solutions of the governing model are obtained by applying GDM and DTM and good agreement is achieved with numerical Runge-Kutta method (RK4). From the results, it is observed that an increase in Duffing term resulted in the increase of the frequency of the micro-beam. An increase in the foundation term also resulted in a corresponding increase in the frequency of the system for both free and forced dynamic responses. This study will enhance the application of tissue engineering in the regeneration of damaged human body tissues.
{"title":"Nonlinear vibrational and rotational analysis of microbeams in nanobiomaterials using Galerkin decomposition and differential transform methods","authors":"O. Adeleye, A. Atitebi, A. Yinusa","doi":"10.32973/jcam.2021.001","DOIUrl":"https://doi.org/10.32973/jcam.2021.001","url":null,"abstract":"In this paper, a nonlinear vibrational and rotational analysis of microbeams in nanobiomaterials using Galerkin Decomposition (GDM) and Differential Transform Methods (DTM) is presented. The dependency of cell migration and growth on nanoscaffold porosity and pore size architecture in tissue regeneration is governed by a dynamic model for the nonlinear vibration and rotation of the microbeams of nanobiomaterials and represented by a set of nonlinear partial differential equations. The solutions of the governing model are obtained by applying GDM and DTM and good agreement is achieved with numerical Runge-Kutta method (RK4). From the results, it is observed that an increase in Duffing term resulted in the increase of the frequency of the micro-beam. An increase in the foundation term also resulted in a corresponding increase in the frequency of the system for both free and forced dynamic responses. This study will enhance the application of tissue engineering in the regeneration of damaged human body tissues.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"79 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86203249","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 work presents a comparative study of Unsteady Reynolds–Averaged Navier–Stokes (URANS), Detached Eddy Simulations (DES) and Delayed Detached Eddy Simulations (DDES) turbulence modeling approaches by performing numerical investigation with the ANSYS-FLUENT software package on a full-scale model of the Jetstream 31 aircraft. The lift and drag coefficients obtained from different models are compared with flight test data, wind tunnel data and theoretical estimates. The different turbulence models are also compared with each other on the basis of pressure coefficient distributions and velocity fluctuations along various lines and sections of the aircraft. For the mesh and the conditions presented in this study, the DDES Spalart–Allmaras model gives the best overall results.
{"title":"A comparative study of URANS, DDES and DES simulations of Jetstream 31 aircraft near the compressibility limit","authors":"Hrishabh Chaudhary, Nicolas Ledos, L. Könözsy","doi":"10.32973/jcam.2021.009","DOIUrl":"https://doi.org/10.32973/jcam.2021.009","url":null,"abstract":"This work presents a comparative study of Unsteady Reynolds–Averaged Navier–Stokes (URANS), Detached Eddy Simulations (DES) and Delayed Detached Eddy Simulations (DDES) turbulence modeling approaches by performing numerical investigation with the ANSYS-FLUENT software package on a full-scale model of the Jetstream 31 aircraft. The lift and drag coefficients obtained from different models are compared with flight test data, wind tunnel data and theoretical estimates. The different turbulence models are also compared with each other on the basis of pressure coefficient distributions and velocity fluctuations along various lines and sections of the aircraft. For the mesh and the conditions presented in this study, the DDES Spalart–Allmaras model gives the best overall results.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"93 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83342348","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}
The stochastic turbulence model developed by Professor Czibere provides a means of clarifying the flow conditions in pipes and of describing the heat evolution caused by shear stresses in the fluid. An important part of the theory is a consideration of the heat transfer-diffusion caused by heat generation. Most of the heat is generated around the pipe wall. One part of the heat enters its environment through the wall of the tube (heat transfer), the other part spreads in the form of diffusion in the liquid, increasing its temperature. The heat conduction differential equation related to the model contains the characteristics describing the turbulent flow, which decisively influence the resulting temperature field, appear. A weak solution of the boundary value problem is provided by Bubnov-Galerkin’s variational principle. The axially symmetric domain analyzed is discretized by a geometrically graded mesh of a high degree of p-version finite elements, this method is capable of describing substantial changes in the temperature gradient in the boundary layer. The novelty of this paper is the application of the p-version finite element method to the heat diffusion problem using Czibere’s turbulence model. Since the material properties depend on temperature, the problem is nonlinear, therefore its solution can be obtained by iteration. The temperature states of the pipes are analyzed for a variety of technical parameters, and useful suggestions are proposed for engineering designs.
{"title":"Finding a weak solution of the heat diffusion differential equation for turbulent flow by Galerkin's variation method using p-version finite elements","authors":"I. Páczelt","doi":"10.32973/jcam.2021.008","DOIUrl":"https://doi.org/10.32973/jcam.2021.008","url":null,"abstract":"The stochastic turbulence model developed by Professor Czibere provides a means of clarifying the flow conditions in pipes and of describing the heat evolution caused by shear stresses in the fluid. An important part of the theory is a consideration of the heat transfer-diffusion caused by heat generation. Most of the heat is generated around the pipe wall. One part of the heat enters its environment through the wall of the tube (heat transfer), the other part spreads in the form of diffusion in the liquid, increasing its temperature. The heat conduction differential equation related to the model contains the characteristics describing the turbulent flow, which decisively influence the resulting temperature field, appear. A weak solution of the boundary value problem is provided by Bubnov-Galerkin’s variational principle. The axially symmetric domain analyzed is discretized by a geometrically graded mesh of a high degree of p-version finite elements, this method is capable of describing substantial changes in the temperature gradient in the boundary layer. The novelty of this paper is the application of the p-version finite element method to the heat diffusion problem using Czibere’s turbulence model. Since the material properties depend on temperature, the problem is nonlinear, therefore its solution can be obtained by iteration. The temperature states of the pipes are analyzed for a variety of technical parameters, and useful suggestions are proposed for engineering designs.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"24 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89752929","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}
The Széchenyi Chain Bridge is a 170-year-old historical structure located in the downtown of Budapest. The superstructure of the bridge was reconstructed several times in its history and currently the renewal process of the bridge is under consideration. According to the current plans main girders, chain elements and cross-girders will remain the old structure and the deck system will be replaced by a new orthotropic steel deck. The Budapest University of Technology and Economics, Department of Structural Engineering was involved in the design process and in the assessment of the remaining elements’ condition within the last 5 years. During the project authors were faced with numerous specific important and challenging structural problems, modelling specialties, advanced design methods and research interest. The main part of these unusual characteristics come from the layout of the historical structure, long time traffic and corrosion problems. One of the most important questions during the structural analysis is the condition and rotational capacity of the pins between the chain elements. The chain system is more than 100 years old and the rotational capacity of the pins is questionable due to corrosion and friction. This phenomenon significantly influences the static behaviour of the chain elements and the whole suspending system. The current paper presents the numerical and on-site experimental program on the investigation of the rotational capacity of the pins. A second important question was related to the condition of current deck system. Significant corrosion damage was observed on the steel stringers which might cause damage or local collapse of the bridge deck under public transportation loads. Advanced numerical model using probabilistic analysis (FORM) and measurement based corrosion models are applied to make a risk assessment of the deck system's capability to maintain and keep the current traffic on the bridge before the deck will be replaced. Via this bridge inspection and investigation project the authors would like to demonstrate the application of advanced numerical modelling based design techniques and the industrial application of research models for lifetime assessment and risk analysis of historical structures.
{"title":"Damage assessment of the historical Széchenyi Chain Bridge","authors":"L. Dunai, B. Kövesdi","doi":"10.32973/jcam.2020.007","DOIUrl":"https://doi.org/10.32973/jcam.2020.007","url":null,"abstract":"The Széchenyi Chain Bridge is a 170-year-old historical structure located in the downtown of Budapest. The superstructure of the bridge was reconstructed several times in its history and currently the renewal process of the bridge is under consideration. According to the current plans main girders, chain elements and cross-girders will remain the old structure and the deck system will be replaced by a new orthotropic steel deck. The Budapest University of Technology and Economics, Department of Structural Engineering was involved in the design process and in the assessment of the remaining elements’ condition within the last 5 years. During the project authors were faced with numerous specific important and challenging structural problems, modelling specialties, advanced design methods and research interest. The main part of these unusual characteristics come from the layout of the historical structure, long time traffic and corrosion problems. One of the most important questions during the structural analysis is the condition and rotational capacity of the pins between the chain elements. The chain system is more than 100 years old and the rotational capacity of the pins is questionable due to corrosion and friction. This phenomenon significantly influences the static behaviour of the chain elements and the whole suspending system. The current paper presents the numerical and on-site experimental program on the investigation of the rotational capacity of the pins. A second important question was related to the condition of current deck system. Significant corrosion damage was observed on the steel stringers which might cause damage or local collapse of the bridge deck under public transportation loads. Advanced numerical model using probabilistic analysis (FORM) and measurement based corrosion models are applied to make a risk assessment of the deck system's capability to maintain and keep the current traffic on the bridge before the deck will be replaced. Via this bridge inspection and investigation project the authors would like to demonstrate the application of advanced numerical modelling based design techniques and the industrial application of research models for lifetime assessment and risk analysis of historical structures.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"105 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77805139","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 deals with four different derivations of the governing equations of a solenoid plunger with lumped-parameter. Energy-based modeling is employed with extended Hamilton's principle with independent generalized coordinates and generalized momenta in order to be applicable to composite Lagrange's equations. In the electromechanical models, displacements and charges are regarded to be generalized coordinates, mechanical momenta and flux linkages are the generalized momenta. The derived systems of differential equations are solved numerically with the Runge-Kutta method.
{"title":"Generalized displacements and momenta formulations of an electromechanical plunger","authors":"T. Szabó, L. Rónai","doi":"10.32973/jcam.2020.010","DOIUrl":"https://doi.org/10.32973/jcam.2020.010","url":null,"abstract":"This paper deals with four different derivations of the governing equations of a solenoid plunger with lumped-parameter. Energy-based modeling is employed with extended Hamilton's principle with independent generalized coordinates and generalized momenta in order to be applicable to composite Lagrange's equations. In the electromechanical models, displacements and charges are regarded to be generalized coordinates, mechanical momenta and flux linkages are the generalized momenta. The derived systems of differential equations are solved numerically with the Runge-Kutta method.","PeriodicalId":47168,"journal":{"name":"Journal of Applied and Computational Mechanics","volume":"25 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84005458","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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