BACKGROUND Limb lengthening techniques play an increasingly important role in the pediatric orthopedic field.The principles of the osteogenesis distraction bonded traditionally with external fixators;however,the recen...BACKGROUND Limb lengthening techniques play an increasingly important role in the pediatric orthopedic field.The principles of the osteogenesis distraction bonded traditionally with external fixators;however,the recent deployment of fully implantable systems has been able to overcome severities related to external fixators.The PRECICE®is an implantable limb lengthening intramedullary nail system that is remotely controlled and magnetically driven.AIM To review the current literature available on this matter in order to assess the PRECICE clinical and radiological outcomes and its possible complications in a population of pediatric patients undergoing limb lengthening.METHODS Only five studies met the inclusion criteria and were consequently included in the review for a total of 131 patients and 135 femurs.The clinical and radiological outcomes of interest were:the main lengthening obtained,the distraction rate,the period of time to full weight bearing,the consolidation index,and the Association for the Study and Application of Methods of Ilizarov score.RESULTS In conclusion,data collected from the articles under investigation were comparable with the exception of the consolidation index.Unfortunately,the study population was too small and the patients’follow-up was too short to make definitive conclusions.CONCLUSION This review shows that the PRECICE Nail System is still a therapeutic challenge in limb lengthening for pediatric orthopedic surgeons;however,careful preoperative planning and an accurate surgical technique could allow the correction of more complex deformities with a low rate of complications.展开更多
针对核反应堆多物理场耦合模拟中传统程序效率低、精度不足的问题,研究基于开源耦合库preCICE及其适配器OpenFOAM-adapter,构建通用三维核热耦合程序。中子物理模块采用课题组研发的有限体积法中子输运程序,热工水力模块集成三维固体导...针对核反应堆多物理场耦合模拟中传统程序效率低、精度不足的问题,研究基于开源耦合库preCICE及其适配器OpenFOAM-adapter,构建通用三维核热耦合程序。中子物理模块采用课题组研发的有限体积法中子输运程序,热工水力模块集成三维固体导热(laplacianFoam)与流体对流换热模型(buoyantPimpleFoam),通过对preCICE官方OpenFOAM-adapter进行功能拓展,引入OpenFOAM的单元集合(cellSet)机制及其区域管理工具topoSet以界定耦合域;并在配置文件preciceDict中配置volumeCenters字段激活体积耦合模式,实现了中子学与热工水力学求解器间基于非匹配网格的数据映射。选取压水堆(Pressurized Water Reactor,PWR)单棒基准题开展网格无关性分析,对比最近邻映射、最近投影映射、径向基函数映射等数据传递方法。结果表明:程序可精确输出三维功率分布、中子通量密度场及速度场,冷却剂出口平均温度相对误差小于0.1%,包壳最高温度相对误差0.14%,计算结果与文献计算值符合较好。该程序突破传统定制化开发模式,支持异构网格差异化配置与大规模并行计算,可为反应堆安全分析、优化设计等提供参考工具。展开更多
In this work,the sharp-interface immersed boundary(IB)method proposed by Mittal et al.(J Comput Phys 227(10):4825–4852,2008)is extended to fluid-structure-inter-action(FSI)simulation of parachute inflation by utilizi...In this work,the sharp-interface immersed boundary(IB)method proposed by Mittal et al.(J Comput Phys 227(10):4825–4852,2008)is extended to fluid-structure-inter-action(FSI)simulation of parachute inflation by utilizing several open-source tools.The method employs a Cartesian-grid ghost-cell methodology to accurately repre-sent the immersed boundary,and it is suitable for solving moving-boundary flows with arbitrarily complex geometries.The finite-element code CalculiX is employed to solve the structural dynamics of the parachute system.The IB flow solver is cou-pled with CalculiX in a minimally-invasive manner using the multi-physics coupling library preCICE.The implicit fluid-structure coupling together with the Aitken adaptive under-relaxation scheme is considered to improve the numerical accuracy and stabil-ity.The developed approach is validated by a benchmark FSI case.Numerical experi-ments on the inflation process of several typical parachutes are further conducted.The breathing process,flow structure,canopy displacement and drag coefficient are analyzed to demonstrate the applicability of the present approach for simulating para-chute inflation.展开更多
文摘BACKGROUND Limb lengthening techniques play an increasingly important role in the pediatric orthopedic field.The principles of the osteogenesis distraction bonded traditionally with external fixators;however,the recent deployment of fully implantable systems has been able to overcome severities related to external fixators.The PRECICE®is an implantable limb lengthening intramedullary nail system that is remotely controlled and magnetically driven.AIM To review the current literature available on this matter in order to assess the PRECICE clinical and radiological outcomes and its possible complications in a population of pediatric patients undergoing limb lengthening.METHODS Only five studies met the inclusion criteria and were consequently included in the review for a total of 131 patients and 135 femurs.The clinical and radiological outcomes of interest were:the main lengthening obtained,the distraction rate,the period of time to full weight bearing,the consolidation index,and the Association for the Study and Application of Methods of Ilizarov score.RESULTS In conclusion,data collected from the articles under investigation were comparable with the exception of the consolidation index.Unfortunately,the study population was too small and the patients’follow-up was too short to make definitive conclusions.CONCLUSION This review shows that the PRECICE Nail System is still a therapeutic challenge in limb lengthening for pediatric orthopedic surgeons;however,careful preoperative planning and an accurate surgical technique could allow the correction of more complex deformities with a low rate of complications.
文摘针对核反应堆多物理场耦合模拟中传统程序效率低、精度不足的问题,研究基于开源耦合库preCICE及其适配器OpenFOAM-adapter,构建通用三维核热耦合程序。中子物理模块采用课题组研发的有限体积法中子输运程序,热工水力模块集成三维固体导热(laplacianFoam)与流体对流换热模型(buoyantPimpleFoam),通过对preCICE官方OpenFOAM-adapter进行功能拓展,引入OpenFOAM的单元集合(cellSet)机制及其区域管理工具topoSet以界定耦合域;并在配置文件preciceDict中配置volumeCenters字段激活体积耦合模式,实现了中子学与热工水力学求解器间基于非匹配网格的数据映射。选取压水堆(Pressurized Water Reactor,PWR)单棒基准题开展网格无关性分析,对比最近邻映射、最近投影映射、径向基函数映射等数据传递方法。结果表明:程序可精确输出三维功率分布、中子通量密度场及速度场,冷却剂出口平均温度相对误差小于0.1%,包壳最高温度相对误差0.14%,计算结果与文献计算值符合较好。该程序突破传统定制化开发模式,支持异构网格差异化配置与大规模并行计算,可为反应堆安全分析、优化设计等提供参考工具。
基金This work is supported by the Open Project of Key Laboratory of Aerospace EDLA,CASC(Grant No.EDL19092128)Key Laboratory of Computational Aerodynamics,AVIC Aerodynamics Research Institute(Grant No.YL2022XFX0409).
文摘In this work,the sharp-interface immersed boundary(IB)method proposed by Mittal et al.(J Comput Phys 227(10):4825–4852,2008)is extended to fluid-structure-inter-action(FSI)simulation of parachute inflation by utilizing several open-source tools.The method employs a Cartesian-grid ghost-cell methodology to accurately repre-sent the immersed boundary,and it is suitable for solving moving-boundary flows with arbitrarily complex geometries.The finite-element code CalculiX is employed to solve the structural dynamics of the parachute system.The IB flow solver is cou-pled with CalculiX in a minimally-invasive manner using the multi-physics coupling library preCICE.The implicit fluid-structure coupling together with the Aitken adaptive under-relaxation scheme is considered to improve the numerical accuracy and stabil-ity.The developed approach is validated by a benchmark FSI case.Numerical experi-ments on the inflation process of several typical parachutes are further conducted.The breathing process,flow structure,canopy displacement and drag coefficient are analyzed to demonstrate the applicability of the present approach for simulating para-chute inflation.
