As JET is developing and testing operational scenarios for higher fusion performance,an increase in pulse disruptivity is being observed.On a deeper analysis,we find that several radiative phenomena play an active rol...As JET is developing and testing operational scenarios for higher fusion performance,an increase in pulse disruptivity is being observed.On a deeper analysis,we find that several radiative phenomena play an active role in determining the outcome of the pulse.The analysis is enabled by the use of real-time tomography based on the bolometer diagnostic.Even though plasma tomography is an inverse problem,we use machine learning to train a forward model that provides the radiation profile directly,based on a single matrix multiplication step.This model is used to investigate radiative phenomena including sawtooth crashes,ELMs and MARFE,and their relationship to the radiated power in different regions of interest.In particular,we use realtime tomography to monitor the core region,and to throw an alarm whenever core radiation exceeds a certain threshold.Our results suggest that this measure alone can anticipate a significant fraction of disruptions in the JET baseline scenario.展开更多
Even when damaged by injury or disease bone tissue has the remarkable ability to regenerate.When this process is limited by large size bone defects,tissue engineering is responsible for restoring,maintaining or improv...Even when damaged by injury or disease bone tissue has the remarkable ability to regenerate.When this process is limited by large size bone defects,tissue engineering is responsible for restoring,maintaining or improving tissue function.Scaffolds are support structures,designed to be implanted in the damaged site,supporting mechanical loads and protecting the regenerating bone tissue.In this paper,3D-printed PLA scaffolds with three different porosity values and two different geometries were experimentally and numerically characterized.Micro-CT analysis showed that fused filament fabrication can be used to produce scaffolds with the desired porosity and 100%of interconnected pores.Under monotonical compression,scaffolds apparent compressive modulus increased from 89 to 918 MPa,while yield stress increased from 2.9 to 27.5 MPa as porosity decreased from 70 to 30%.Open porosity decreased up to 8%on aligned scaffolds and 14%on staggered scaffolds,after compression,while scaffold’s surface-to-volume ratio highest reduction(7.48 to 4.55 mm−1)was obtained with aligned low porosity scaffolds.Micro-CT volume reconstruction allowed for scaffold simplified numerical models to be built and analyzed.Excellent agreement was found when predicting scaffold’s apparent compressive modulus.Overall,it can be concluded that 3D printing is a viable scaffold manufacturing technique for trabecular bone replacement.展开更多
基金This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No.633053.The views and opinions expressed herein do not necessarily reflect those of the European Commission.IPFN(Instituto de Plasmas e Fusão Nuclear)received financial support from FCT(Fundação para a Ciência e a Tecnologia)through projects UIDB/50010/2020 and UIDP/50010/2020.The authors are thankful for the granted use of computational resources provided by CCFE/UKAEA at Culham,UK.
文摘As JET is developing and testing operational scenarios for higher fusion performance,an increase in pulse disruptivity is being observed.On a deeper analysis,we find that several radiative phenomena play an active role in determining the outcome of the pulse.The analysis is enabled by the use of real-time tomography based on the bolometer diagnostic.Even though plasma tomography is an inverse problem,we use machine learning to train a forward model that provides the radiation profile directly,based on a single matrix multiplication step.This model is used to investigate radiative phenomena including sawtooth crashes,ELMs and MARFE,and their relationship to the radiated power in different regions of interest.In particular,we use realtime tomography to monitor the core region,and to throw an alarm whenever core radiation exceeds a certain threshold.Our results suggest that this measure alone can anticipate a significant fraction of disruptions in the JET baseline scenario.
基金This work was supported by FCT,through IDMEC under LAETA(project UIDB/50022/2020)CeFEMA(UID/CTM/04540/2019)+1 种基金CERENA(UIDB/04028/2020)IPFN activities also received financial support from FCT through Projects UIDB/50010/2020 and UIDP/50010/2020.
文摘Even when damaged by injury or disease bone tissue has the remarkable ability to regenerate.When this process is limited by large size bone defects,tissue engineering is responsible for restoring,maintaining or improving tissue function.Scaffolds are support structures,designed to be implanted in the damaged site,supporting mechanical loads and protecting the regenerating bone tissue.In this paper,3D-printed PLA scaffolds with three different porosity values and two different geometries were experimentally and numerically characterized.Micro-CT analysis showed that fused filament fabrication can be used to produce scaffolds with the desired porosity and 100%of interconnected pores.Under monotonical compression,scaffolds apparent compressive modulus increased from 89 to 918 MPa,while yield stress increased from 2.9 to 27.5 MPa as porosity decreased from 70 to 30%.Open porosity decreased up to 8%on aligned scaffolds and 14%on staggered scaffolds,after compression,while scaffold’s surface-to-volume ratio highest reduction(7.48 to 4.55 mm−1)was obtained with aligned low porosity scaffolds.Micro-CT volume reconstruction allowed for scaffold simplified numerical models to be built and analyzed.Excellent agreement was found when predicting scaffold’s apparent compressive modulus.Overall,it can be concluded that 3D printing is a viable scaffold manufacturing technique for trabecular bone replacement.
