In-site soil flushing and aeration are the typical synergetic remediation technology for contaminated sites.The surfactant present in flushing solutions is bound to affect the aeration efficiency.The purpose of this s...In-site soil flushing and aeration are the typical synergetic remediation technology for contaminated sites.The surfactant present in flushing solutions is bound to affect the aeration efficiency.The purpose of this study is to evaluate the effect of surfactant frequently used in soil flushing on the oxygen mass transfer in micro-nano-bubble(MNB)aeration system.Firstly,bio-surfactants and chemical surfactants were used to investigate their effects on Sauter mean diameter of bubble(dBS),gas holdup(ε),volumetric mass-transfer coefficient(kLa)and liquid-side mass-transfer coefficient(kL)in the MNB aeration system.Then,based upon the experimental results,the Sardeing's and Frossling's models were modified to describe the effect of surfactant on kL in the MNB aeration.The results showed that,for the twenty aqueous surfactant solutions,with the increase in surfactant concentration,the value of dBS,kLa and kL decreased,while the value ofεand gas-liquid interfacial area(a)increased.These phenomena were mainly attributed to the synergistic effects of immobile bubble surface and the suppression of coalescence in the surfactant solutions.In addition,with the presence of electric charge,MNBs in anionic surfactant solutions were smaller and higher in number than in non-ionic surfactant solutions.Furthermore,the accumulation of surfactant on the gas-liquid interface was more conspicuous for small MNB,so the reduction of kL in anionic surfactant solutions was larger than that in non-ionic surfactant solutions.Besides,the modified Frossling's model predicted the effect of surfactant on kL in MNB aeration system with reasonable accuracy.展开更多
This article comments on the article by Du et al,who conducted a randomized controlled trial aiming at evaluating the effectiveness of a novel spray flushing system in cleaning flexible endoscopes while minimizing dam...This article comments on the article by Du et al,who conducted a randomized controlled trial aiming at evaluating the effectiveness of a novel spray flushing system in cleaning flexible endoscopes while minimizing damage to the working channels.We share our perspective on the importance of improving endoscope reprocessing methods.The findings highlight the spray flushing system's capacity to improve cleaning efficacy while minimizing damage,suggesting that it might be important in enhancing endoscope reprocessing procedures.展开更多
The advancement in endoscopic technology and techniques has increased its use in the diagnosis and treatment of gastrointestinal diseases.Reprocessing of reusable endoscopes remains a challenge.Inadequate reprocessing...The advancement in endoscopic technology and techniques has increased its use in the diagnosis and treatment of gastrointestinal diseases.Reprocessing of reusable endoscopes remains a challenge.Inadequate reprocessing leads to bacterial contamination of the endoscope,a significant cause of endoscope-related infections.To thoroughly address the complexities of cleaning a flexible endo-scope,various cleaning methods have been devised and tested across different studies.This letter evaluates one such method,spray flushing for flexible gastro-scopes,developed and tested in a randomized controlled trial by Du et al.Based on the post-processing test results for this method,Du et al conclude that there is improved cleaning efficacy and reduced damage compared to manual brush cleaning.The validity and reliability of the results could be further enhanced by carefully considering the study design and a few underlying concepts that contribute to the reprocessing quality of different types of endoscopes.展开更多
The Flush Airdata Sensing （FADS） system and its pressure model are presented briefly. The improved algorithm for calculating the impact pressure, static pressure and modifying coefficient are studied. First, the non...The Flush Airdata Sensing （FADS） system and its pressure model are presented briefly. The improved algorithm for calculating the impact pressure, static pressure and modifying coefficient are studied. First, the non-linear equations are simplified using Moore-Penrose inverse. Then the impact pressure and static pressure are computed with the improved iteration and BP neural network. Both the two improved algorithms meet the requirements of the flush airdata sensing system on precision, reliability and speed. BP neural network has great advantages on real-time requirements, for it needs only 5% time to reach the required precision comparing to the original algorithm.展开更多
针对先进高性能飞行器对高精度大气数据的测控需求,研发设计了一套适用于亚声速飞行器的嵌入式大气数据传感(flush air data sensing,FADS)系统。该系统首先基于数值建模技术建立了FADS系统模型的压力数据库,并针对建模数据精度及风洞...针对先进高性能飞行器对高精度大气数据的测控需求,研发设计了一套适用于亚声速飞行器的嵌入式大气数据传感(flush air data sensing,FADS)系统。该系统首先基于数值建模技术建立了FADS系统模型的压力数据库,并针对建模数据精度及风洞试验校准数据分析了Ma=0.2~0.4对应的压力误差限;其次,开发了攻角实时解算算法,并集成到工程原理样机中;最后基于风洞试验和飞行试验对FADS系统的实时解算算法及样机进行了系统评估,并通过事后模型算法对攻角进行重新解算以评估攻角实时解算算法的可靠性。结果表明:(1)与机载惯性导航系统等其他独立测试系统解算的数据相比,飞行试验中FADS系统采用的攻角实时解算方法精度整体较好,攻角误差小于1°,在关键段小于0.5°;基于不同模型建立的FADS系统攻角解算方法得到的攻角数值基本一致,证实了开发的实时解算算法的可靠性。(2)基于风洞试验及飞行试验数据对算法误差限的考核结果显示,飞行试验初始阶段实时解算的攻角值产生波动是压力输入波动误差限较大造成的,高空低速时的压力波动幅值大是实时解算攻角值偏差较大的主要原因;建立的FADS系统的攻角解算方法在算法误差限范围内的压力波动对攻角解算值影响较小,但超过算法误差限的压力波动对攻角解算值影响显著。高空低速飞行器FADS系统对测压传感器精度水平及工程实施水平要求较高,在实际工程应用中应尽量保证测压传感器的精度水平。展开更多
针对亚声速飞行器对高精度飞行参数的测控需求,研发了一套亚声速嵌入式大气数据传感(flush air data sensing,FADS)系统,集成工程样机,并通过风洞试验及飞行试验进行系统考核评估。基于计算流体动力学(computational fluid dynamics,CFD...针对亚声速飞行器对高精度飞行参数的测控需求,研发了一套亚声速嵌入式大气数据传感(flush air data sensing,FADS)系统,集成工程样机,并通过风洞试验及飞行试验进行系统考核评估。基于计算流体动力学(computational fluid dynamics,CFD)方法首先建立FADS系统压力数据库,并通过风洞试验考核了模型算法在低亚声速时的误差限;其次,集成融合实时解算算法的FADS工程原理样机;最后通过飞行试验考核了工程样机的工程适用性。结果表明:(1)与机载的其他独立测试系统相比,FADS攻角实时解算精度高,攻角偏差≤1°,关键段攻角偏差≤0.5°;事后重建的攻角数据与飞行试验FADS系统实时解算数据一致,证实FADS实时攻角解算方法可靠;(2)风洞及飞行试验校核数据表明,FADS实时攻角输出数据在飞行试验初始段的波动是由输入压力波动较大导致,特别是在高空低速段,输入压力波动幅值超过算法的误差限,导致实时攻角解算数值波动较大;(3)CFD仿真结果表明,输入压力波动位于算法误差限内对攻角输出精度影响较小,超过算法误差限的压力幅值波动对实时攻角输出精度影响极大。高空低速飞行器FADS系统对压力传感器等硬件精度及工程实现水平要求较高,应尽量保证工程实施精度。展开更多
现代固定翼飞机受头部火控雷达等设备限制,无法在机头驻点附近开设测压孔,缺乏驻点压力会导致常规嵌入式大气数据传感系统测试精度大大下降。针对典型固定翼飞机常用的菱形前体外形,对无驻点压力FADS(Flush Air Data Sensing)系统解算...现代固定翼飞机受头部火控雷达等设备限制,无法在机头驻点附近开设测压孔,缺乏驻点压力会导致常规嵌入式大气数据传感系统测试精度大大下降。针对典型固定翼飞机常用的菱形前体外形,对无驻点压力FADS(Flush Air Data Sensing)系统解算算法及精度进行研究。通过亚跨声速风洞校准试验,获得了测压孔压力分布特性,基于卡尔曼滤波算法构建了无驻点压力FADS技术。通过引入差压数据改进了算法,改进算法实现了部分解耦,提高了解算精度且迭代次数较少,计算量较小。风洞试验结果表明:无驻点压力解算算法可以在外插车次下较好地解算大气参数,其中迎角测量精度为0.33°,侧滑角测量精度为0.30°,静压测量精度为0.67%,马赫数测量精度为0.011。展开更多
Post-reperfusion syndrome(PRS)in liver transplant recipients remains one of the most dreaded complications in liver transplant surgery.PRS can impact the short-term and long-term patient and graft outcomes.The definit...Post-reperfusion syndrome(PRS)in liver transplant recipients remains one of the most dreaded complications in liver transplant surgery.PRS can impact the short-term and long-term patient and graft outcomes.The definition of PRS has evolved over the years,from changes in arterial blood pressures and heart and/or de-creases in the systemic vascular resistance and cardiac output to including the fibrinolysis and grading the severity of PRS.However,all that did not reflect on the management of PRS or its impact on the outcomes.In recent years,new scientific techniques and new technology have been in the pipeline to better understand,manage and maybe prevent PRS.These new methods and techniques are still in the infancy,and they have to be proven not in prevention and management of PRS but their effects in the patient and graft outcomes.In this article,we will review the long history of PRS,its definition,etiology,mana-gement and most importantly the new advances in science and technology to prevent and properly manage PRS.展开更多
The development and application of large Die⁃Casting Al Alloy(DCAA)parts and Thermo⁃Formed Steel Sheets(TFSS)in Body⁃in⁃White(BIW)have created higher demands for the joining technology of high⁃strength steel/Al dissim...The development and application of large Die⁃Casting Al Alloy(DCAA)parts and Thermo⁃Formed Steel Sheets(TFSS)in Body⁃in⁃White(BIW)have created higher demands for the joining technology of high⁃strength steel/Al dissimilar materials.As an emerging technology,Flush Self⁃Piercing Riveting(FSPR)is still in the experimental phase and undergoing small batch equipment verification.This paper focuses on the joining methods for DCAA and TFSS in BIW,investigating the joining mechanisms,technical features,and forming principles of FSPR for steel/Al dissimilar materials with two⁃layer or three⁃layer plate combinations.Considering the TL4225/C611/CR5 sheet combination as a subject,the forming mechanism of high⁃quality joints was studied,and a physical and mathematical model was established to depict the relationship between the filling amount of the arc⁃gap and die dimensions,as well as the extrusion amount.This model effectively illustrates the relationship between the filling amount of the flowing metal in the arc⁃gap and critical parameters,such as die dimensions and feeding amounts.By simplifying the process of selecting joining parameters,it significantly reduces both the time and experimental workload associated with parameter selection.This provides a technical foundation for the application of DAAA and TFSS parts in BIW,enabling the rapid choice of appropriate joining parameters to meet the requirements for obtaining high⁃quality joints.The model can be effectively utilized to investigate the relationships between key parameters,including arc⁃gap radius,plate thickness,rivet arc radius,nail head radius,groove width,and feeding amount,while keeping other parameters constant.This approach provides a theoretical foundation for the design of Friction Stir Processing(FSP)joints and aids in the selection of optimal parameters.展开更多
基金financially supported by the National Natural Science Foundation of China(41877240)National Key Research and Development Program of China(2018YFC1802300)Scientific Research Foundation of Graduate School of Southeast University(YBPY2154).
文摘In-site soil flushing and aeration are the typical synergetic remediation technology for contaminated sites.The surfactant present in flushing solutions is bound to affect the aeration efficiency.The purpose of this study is to evaluate the effect of surfactant frequently used in soil flushing on the oxygen mass transfer in micro-nano-bubble(MNB)aeration system.Firstly,bio-surfactants and chemical surfactants were used to investigate their effects on Sauter mean diameter of bubble(dBS),gas holdup(ε),volumetric mass-transfer coefficient(kLa)and liquid-side mass-transfer coefficient(kL)in the MNB aeration system.Then,based upon the experimental results,the Sardeing's and Frossling's models were modified to describe the effect of surfactant on kL in the MNB aeration.The results showed that,for the twenty aqueous surfactant solutions,with the increase in surfactant concentration,the value of dBS,kLa and kL decreased,while the value ofεand gas-liquid interfacial area(a)increased.These phenomena were mainly attributed to the synergistic effects of immobile bubble surface and the suppression of coalescence in the surfactant solutions.In addition,with the presence of electric charge,MNBs in anionic surfactant solutions were smaller and higher in number than in non-ionic surfactant solutions.Furthermore,the accumulation of surfactant on the gas-liquid interface was more conspicuous for small MNB,so the reduction of kL in anionic surfactant solutions was larger than that in non-ionic surfactant solutions.Besides,the modified Frossling's model predicted the effect of surfactant on kL in MNB aeration system with reasonable accuracy.
文摘This article comments on the article by Du et al,who conducted a randomized controlled trial aiming at evaluating the effectiveness of a novel spray flushing system in cleaning flexible endoscopes while minimizing damage to the working channels.We share our perspective on the importance of improving endoscope reprocessing methods.The findings highlight the spray flushing system's capacity to improve cleaning efficacy while minimizing damage,suggesting that it might be important in enhancing endoscope reprocessing procedures.
文摘The advancement in endoscopic technology and techniques has increased its use in the diagnosis and treatment of gastrointestinal diseases.Reprocessing of reusable endoscopes remains a challenge.Inadequate reprocessing leads to bacterial contamination of the endoscope,a significant cause of endoscope-related infections.To thoroughly address the complexities of cleaning a flexible endo-scope,various cleaning methods have been devised and tested across different studies.This letter evaluates one such method,spray flushing for flexible gastro-scopes,developed and tested in a randomized controlled trial by Du et al.Based on the post-processing test results for this method,Du et al conclude that there is improved cleaning efficacy and reduced damage compared to manual brush cleaning.The validity and reliability of the results could be further enhanced by carefully considering the study design and a few underlying concepts that contribute to the reprocessing quality of different types of endoscopes.
文摘The Flush Airdata Sensing （FADS） system and its pressure model are presented briefly. The improved algorithm for calculating the impact pressure, static pressure and modifying coefficient are studied. First, the non-linear equations are simplified using Moore-Penrose inverse. Then the impact pressure and static pressure are computed with the improved iteration and BP neural network. Both the two improved algorithms meet the requirements of the flush airdata sensing system on precision, reliability and speed. BP neural network has great advantages on real-time requirements, for it needs only 5% time to reach the required precision comparing to the original algorithm.
文摘针对先进高性能飞行器对高精度大气数据的测控需求,研发设计了一套适用于亚声速飞行器的嵌入式大气数据传感(flush air data sensing,FADS)系统。该系统首先基于数值建模技术建立了FADS系统模型的压力数据库,并针对建模数据精度及风洞试验校准数据分析了Ma=0.2~0.4对应的压力误差限;其次,开发了攻角实时解算算法,并集成到工程原理样机中;最后基于风洞试验和飞行试验对FADS系统的实时解算算法及样机进行了系统评估,并通过事后模型算法对攻角进行重新解算以评估攻角实时解算算法的可靠性。结果表明:(1)与机载惯性导航系统等其他独立测试系统解算的数据相比,飞行试验中FADS系统采用的攻角实时解算方法精度整体较好,攻角误差小于1°,在关键段小于0.5°;基于不同模型建立的FADS系统攻角解算方法得到的攻角数值基本一致,证实了开发的实时解算算法的可靠性。(2)基于风洞试验及飞行试验数据对算法误差限的考核结果显示,飞行试验初始阶段实时解算的攻角值产生波动是压力输入波动误差限较大造成的,高空低速时的压力波动幅值大是实时解算攻角值偏差较大的主要原因;建立的FADS系统的攻角解算方法在算法误差限范围内的压力波动对攻角解算值影响较小,但超过算法误差限的压力波动对攻角解算值影响显著。高空低速飞行器FADS系统对测压传感器精度水平及工程实施水平要求较高,在实际工程应用中应尽量保证测压传感器的精度水平。
文摘针对亚声速飞行器对高精度飞行参数的测控需求,研发了一套亚声速嵌入式大气数据传感(flush air data sensing,FADS)系统,集成工程样机,并通过风洞试验及飞行试验进行系统考核评估。基于计算流体动力学(computational fluid dynamics,CFD)方法首先建立FADS系统压力数据库,并通过风洞试验考核了模型算法在低亚声速时的误差限;其次,集成融合实时解算算法的FADS工程原理样机;最后通过飞行试验考核了工程样机的工程适用性。结果表明:(1)与机载的其他独立测试系统相比,FADS攻角实时解算精度高,攻角偏差≤1°,关键段攻角偏差≤0.5°;事后重建的攻角数据与飞行试验FADS系统实时解算数据一致,证实FADS实时攻角解算方法可靠;(2)风洞及飞行试验校核数据表明,FADS实时攻角输出数据在飞行试验初始段的波动是由输入压力波动较大导致,特别是在高空低速段,输入压力波动幅值超过算法的误差限,导致实时攻角解算数值波动较大;(3)CFD仿真结果表明,输入压力波动位于算法误差限内对攻角输出精度影响较小,超过算法误差限的压力幅值波动对实时攻角输出精度影响极大。高空低速飞行器FADS系统对压力传感器等硬件精度及工程实现水平要求较高,应尽量保证工程实施精度。
文摘现代固定翼飞机受头部火控雷达等设备限制,无法在机头驻点附近开设测压孔,缺乏驻点压力会导致常规嵌入式大气数据传感系统测试精度大大下降。针对典型固定翼飞机常用的菱形前体外形,对无驻点压力FADS(Flush Air Data Sensing)系统解算算法及精度进行研究。通过亚跨声速风洞校准试验,获得了测压孔压力分布特性,基于卡尔曼滤波算法构建了无驻点压力FADS技术。通过引入差压数据改进了算法,改进算法实现了部分解耦,提高了解算精度且迭代次数较少,计算量较小。风洞试验结果表明:无驻点压力解算算法可以在外插车次下较好地解算大气参数,其中迎角测量精度为0.33°,侧滑角测量精度为0.30°,静压测量精度为0.67%,马赫数测量精度为0.011。
文摘Post-reperfusion syndrome(PRS)in liver transplant recipients remains one of the most dreaded complications in liver transplant surgery.PRS can impact the short-term and long-term patient and graft outcomes.The definition of PRS has evolved over the years,from changes in arterial blood pressures and heart and/or de-creases in the systemic vascular resistance and cardiac output to including the fibrinolysis and grading the severity of PRS.However,all that did not reflect on the management of PRS or its impact on the outcomes.In recent years,new scientific techniques and new technology have been in the pipeline to better understand,manage and maybe prevent PRS.These new methods and techniques are still in the infancy,and they have to be proven not in prevention and management of PRS but their effects in the patient and graft outcomes.In this article,we will review the long history of PRS,its definition,etiology,mana-gement and most importantly the new advances in science and technology to prevent and properly manage PRS.
文摘The development and application of large Die⁃Casting Al Alloy(DCAA)parts and Thermo⁃Formed Steel Sheets(TFSS)in Body⁃in⁃White(BIW)have created higher demands for the joining technology of high⁃strength steel/Al dissimilar materials.As an emerging technology,Flush Self⁃Piercing Riveting(FSPR)is still in the experimental phase and undergoing small batch equipment verification.This paper focuses on the joining methods for DCAA and TFSS in BIW,investigating the joining mechanisms,technical features,and forming principles of FSPR for steel/Al dissimilar materials with two⁃layer or three⁃layer plate combinations.Considering the TL4225/C611/CR5 sheet combination as a subject,the forming mechanism of high⁃quality joints was studied,and a physical and mathematical model was established to depict the relationship between the filling amount of the arc⁃gap and die dimensions,as well as the extrusion amount.This model effectively illustrates the relationship between the filling amount of the flowing metal in the arc⁃gap and critical parameters,such as die dimensions and feeding amounts.By simplifying the process of selecting joining parameters,it significantly reduces both the time and experimental workload associated with parameter selection.This provides a technical foundation for the application of DAAA and TFSS parts in BIW,enabling the rapid choice of appropriate joining parameters to meet the requirements for obtaining high⁃quality joints.The model can be effectively utilized to investigate the relationships between key parameters,including arc⁃gap radius,plate thickness,rivet arc radius,nail head radius,groove width,and feeding amount,while keeping other parameters constant.This approach provides a theoretical foundation for the design of Friction Stir Processing(FSP)joints and aids in the selection of optimal parameters.
