This paper proposes a novel hybrid method to simulate the dry granular flow of materials over a wide range of inertial numbers that simultaneously covers the quasi-static and dense granular flow regimes. To overcome t...This paper proposes a novel hybrid method to simulate the dry granular flow of materials over a wide range of inertial numbers that simultaneously covers the quasi-static and dense granular flow regimes. To overcome the lack of incremental objectivity whenever large deformations occur in solid-like regimes and to remove computational singularities in fluid-like regimes close to rest, the elastic–perfectly plastic theory based on the Drucker–Prager yield criterion is combined with the theory of dense granular flows. By implementing some new modifications at the boundaries and removing all ghost particles, smoothed particle hydrodynamics （SPH） is used as the framework for the method. A number of benchmark problems have been solved to show the capabilities of the new modified SPH method. Precise prediction of both location and pressure makes the modifications comparable with the previous works on SPH. Finally, the method is used to solve the classic 2D dry granular cliff collapse problem and to model dry granular material flow inside a rotary drum. The outcomes of the numerical simulation show good agreement with tabletop experiments and published results.展开更多
目的探讨支气管肺发育不良(Bronchopulmonary dysplasia,BPD)儿童支气管肺泡灌洗液(Bronchoalveolar lavage fluid,BALF)中Ⅱ型肺泡细胞表面抗原(Kerbs von Lungren 6 antigen,KL-6)、粒细胞集落刺激因子(Granulocyte-colony stimulatin...目的探讨支气管肺发育不良(Bronchopulmonary dysplasia,BPD)儿童支气管肺泡灌洗液(Bronchoalveolar lavage fluid,BALF)中Ⅱ型肺泡细胞表面抗原(Kerbs von Lungren 6 antigen,KL-6)、粒细胞集落刺激因子(Granulocyte-colony stimulating factor,G-CSF)及胰岛素样生长因子(Insulin-like growth factor-1,IGF-1)表达意义,为临床诊疗提供参考。方法选取2020年2月-2023年10月河北梅奥心血管病医院收治的192例BPD患儿,根据吸入氧浓度(Inhalation of oxygen concentration,FiO_(2))分为轻度BPD组(n=103,未用氧)、中度BPD组(n=60,21%<FiO_(2)<30%),重度BPD组(n=29,FiO_(2)≥30%或机械通气)。比较不同吸氧程度BPD患儿出生后不同时间BALF中KL-6、G-CSF、IGF-1表达水平及FeNO、潮气呼吸肺功能。分析BALF中KL-6、G-CSF、IGF-1与吸氧程度、呼出气一氧化氮(Fractional exhaled nitric oxide,FeNO)及潮气呼吸肺功能[达峰容积比(Volume to peak expiratory flow as a proportion of exhaled volume,VPEF/VE)、达峰时间比(Time to peak tidal expiratory flow as a proportion of expiratory time,TPTEF/TE)]的相关性。结果轻度BPD组KL-6表达水平低于中度BPD组、重度BPD组,且中度BPD组低于重度BPD组(P<0.05);轻度BPD组G-CSF表达水平低于中度BPD组、重度BPD组,且中度BPD组低于重度BPD组(P<0.05);轻度BPD组IGF-1表达水平高于中度BPD组、重度BPD组,且中度BPD组高于重度BPD组(P<0.05);轻度BPD组FeNO小于中度BPD组、重度BPD组,VPEF/VE、TPTEF/TE大于中度BPD组、重度BPD组,且中度BPD组FeNO小于重度BPD组,VPEF/VE、TPTEF/TE大于重度BPD组(P<0.05);BPD患儿出生后1 d、7 d、14 d、28 d BALF中KL-6、G-CSF与吸氧程度呈正相关,IGF-1与吸氧程度呈负相关(P<0.05);BPD患儿出生后1 d BALF中KL-6、G-CSF与矫正胎龄40周时FeNO呈正相关,与矫正胎龄40周时VPEF/VE、TPTEF/TE呈负相关(P<0.05);BPD患儿出生后1 d BALF中IGF-1与矫正胎龄40周时FeNO呈负相关,与矫正胎龄40周时VPEF/VE、TPTEF/TE呈正相关(P<0.05)。结论BPD患儿BALF中KL-6、G-CSF、IGF-1与吸氧程度有关,且与远期FeNO及潮气呼吸肺功能有关,对临床干预有一定指导价值。展开更多
文摘This paper proposes a novel hybrid method to simulate the dry granular flow of materials over a wide range of inertial numbers that simultaneously covers the quasi-static and dense granular flow regimes. To overcome the lack of incremental objectivity whenever large deformations occur in solid-like regimes and to remove computational singularities in fluid-like regimes close to rest, the elastic–perfectly plastic theory based on the Drucker–Prager yield criterion is combined with the theory of dense granular flows. By implementing some new modifications at the boundaries and removing all ghost particles, smoothed particle hydrodynamics （SPH） is used as the framework for the method. A number of benchmark problems have been solved to show the capabilities of the new modified SPH method. Precise prediction of both location and pressure makes the modifications comparable with the previous works on SPH. Finally, the method is used to solve the classic 2D dry granular cliff collapse problem and to model dry granular material flow inside a rotary drum. The outcomes of the numerical simulation show good agreement with tabletop experiments and published results.
文摘目的探讨支气管肺发育不良(Bronchopulmonary dysplasia,BPD)儿童支气管肺泡灌洗液(Bronchoalveolar lavage fluid,BALF)中Ⅱ型肺泡细胞表面抗原(Kerbs von Lungren 6 antigen,KL-6)、粒细胞集落刺激因子(Granulocyte-colony stimulating factor,G-CSF)及胰岛素样生长因子(Insulin-like growth factor-1,IGF-1)表达意义,为临床诊疗提供参考。方法选取2020年2月-2023年10月河北梅奥心血管病医院收治的192例BPD患儿,根据吸入氧浓度(Inhalation of oxygen concentration,FiO_(2))分为轻度BPD组(n=103,未用氧)、中度BPD组(n=60,21%<FiO_(2)<30%),重度BPD组(n=29,FiO_(2)≥30%或机械通气)。比较不同吸氧程度BPD患儿出生后不同时间BALF中KL-6、G-CSF、IGF-1表达水平及FeNO、潮气呼吸肺功能。分析BALF中KL-6、G-CSF、IGF-1与吸氧程度、呼出气一氧化氮(Fractional exhaled nitric oxide,FeNO)及潮气呼吸肺功能[达峰容积比(Volume to peak expiratory flow as a proportion of exhaled volume,VPEF/VE)、达峰时间比(Time to peak tidal expiratory flow as a proportion of expiratory time,TPTEF/TE)]的相关性。结果轻度BPD组KL-6表达水平低于中度BPD组、重度BPD组,且中度BPD组低于重度BPD组(P<0.05);轻度BPD组G-CSF表达水平低于中度BPD组、重度BPD组,且中度BPD组低于重度BPD组(P<0.05);轻度BPD组IGF-1表达水平高于中度BPD组、重度BPD组,且中度BPD组高于重度BPD组(P<0.05);轻度BPD组FeNO小于中度BPD组、重度BPD组,VPEF/VE、TPTEF/TE大于中度BPD组、重度BPD组,且中度BPD组FeNO小于重度BPD组,VPEF/VE、TPTEF/TE大于重度BPD组(P<0.05);BPD患儿出生后1 d、7 d、14 d、28 d BALF中KL-6、G-CSF与吸氧程度呈正相关,IGF-1与吸氧程度呈负相关(P<0.05);BPD患儿出生后1 d BALF中KL-6、G-CSF与矫正胎龄40周时FeNO呈正相关,与矫正胎龄40周时VPEF/VE、TPTEF/TE呈负相关(P<0.05);BPD患儿出生后1 d BALF中IGF-1与矫正胎龄40周时FeNO呈负相关,与矫正胎龄40周时VPEF/VE、TPTEF/TE呈正相关(P<0.05)。结论BPD患儿BALF中KL-6、G-CSF、IGF-1与吸氧程度有关,且与远期FeNO及潮气呼吸肺功能有关,对临床干预有一定指导价值。
