The functional piezoelectric ceramic smart aggregate(SA) sensors and actuators,based on piezoelectric ceramic materials such as lead zirconium titanate(PZT),were embedded into the reinforced concrete beams with three-...The functional piezoelectric ceramic smart aggregate(SA) sensors and actuators,based on piezoelectric ceramic materials such as lead zirconium titanate(PZT),were embedded into the reinforced concrete beams with three-point bending under static loading for purposes of damage detection.The SA actuators generated the desired sine sweep excitation signals online and the SA sensors received and detected real-time signals before and after damage.The wavelet analysis and statistical characteristics about damage signals were used as a signal processing and analysis tool to extract the optimal damage information and establish a statistical damage detection algorithm.The damage index-based wavelet analysis and damage probability-based probability and statistics were proposed by PZT wavebased theory and active health monitoring technology.The results showed that the existence of cracks inside largely attenuated the amplitude of active monitoring signal after the damage of beam and the attenuation was related to the severity degree of damage.The innovative statistical algorithm of damage pattern detection based PZT-SA can effectively determine damage probability and damage degree,and provide a prediction for the critical damage location of reinforced concrete structures.The developed method can be utilized for the structural health comprehensive monitoring and damage detection on line of various large-scale concrete structures.展开更多
Structural health monitoring of RC structures under seismic loads has recently attracted much attention in the earthquake engineering research community. In this study, a piezoceramic-based device called ＂smart aggre...Structural health monitoring of RC structures under seismic loads has recently attracted much attention in the earthquake engineering research community. In this study, a piezoceramic-based device called ＂smart aggregate＂ was used for the health monitoring of RC frame structures under earthquake excitations. Three RC moment frames instrumented with smart aggregates were tested using a shaketable with different ground excitation intensities. Distributed piezoceramic- based smart aggregates were embedded in the RC structures and used to monitor their health condition during the tests. The sensitivity and effectiveness of the proposed piezoceramic-based approach were investigated and evaluated by analyzing the measured responses. The displacement ductility demand of the structural members was calculated and compared with the damage index determined from the health monitoring system. The comparison shows that the damage index is compatible with the calculated ductility demand.展开更多
By using redispersible polymer powder（RPP） and carbon fiber（CF） to adjust the flexibility and electrical properties of the smart aggregate, a new kind of smart aggregate with Z type structure was proposed. The stu...By using redispersible polymer powder（RPP） and carbon fiber（CF） to adjust the flexibility and electrical properties of the smart aggregate, a new kind of smart aggregate with Z type structure was proposed. The study shows that Z type aggregate is more sensitive to the feedback of external force than the prism aggregate in the same loading environment, and it indicates that Z type aggregate is more suitable for the research and application of concrete health monitoring. Although the incorporation of RPP would cause the compressive strength of the aggregates and the elastic modulus of hardened cement mortar to reduce slightly within the dosage of RPP by 2.25% because of the polymer film formed in the internal system, this would improve the deformability of the aggregates. In the early loading stage（in the first 60 seconds）, the intelligent concrete specimens implanted with Z type smart aggregate do not show higher sensitivity as expected, although the resistance change rate changes a little bit more, the overall of it is still in balance. Adding RPP could improve the flexibility of smart aggregates exactly, and it plays an active role in prolonging the life of the smart aggregates. By implanting Z type aggregates the damage and failure of the concrete structure could be predicted accurately in this study. The results of this paper will help to promote further research and application of intelligent concrete.展开更多
The most familiar civil engineering structure is reinforced concrete (RC) structure. Performance of structure undergoes changes during their service life with time. Thus, it is of great concern to monitor the health o...The most familiar civil engineering structure is reinforced concrete (RC) structure. Performance of structure undergoes changes during their service life with time. Thus, it is of great concern to monitor the health of RC structure. Structural health monitoring (SHM) is the art of detecting the changes in structure that influences its performance. Various techniques to monitor the health of structure are broadly studied worldwide. PZT based smart aggregate can play an effective role as an advanced tool in the development of structural health monitoring. This research work contributes for proposing a more generous Non-Destructive Evaluation (NDE) technique for structural health monitoring by using smart materials. If performance of a structure deviates from the design parameters with time, appropriate and effective maintenance is required. Considering the relevant need of RC structures, a more sensitive and cost-effective approach by using Electro-Mechanical Impedance (EMI) technique has been proposed for implementation in real-life situations. In general, surface bonded PZT transducer is used for SHM. Since PZT transducers are of very small dimension and brittle in nature, for consistent characteristics, they should be protected from severe environmental condition and other external interruptions. For this reason, PZT transducer is embedded in structure at the time of construction and manufacturing of the embedded transducer is simple. The proposed EMI technique assesses the health of RC structures more rationally by embedding PZT transducer in the structure, whose health is to be monitored over the user specified preset frequency range. The conductance and susceptance signatures are acquired by using LCR meter. At any future point of time, when it is desired to assess the health of structure, the conductance and susceptance signatures are acquired and further utilized for damage detection and quantification. The Root Mean Square Deviation (RMSD) is used to specify damage severity.展开更多
Cement and resin were designed as mixed cementitious materials to study the smart aggregate(SA)of smart concrete.Carbon fiber(CF)and surfactant were taken into consideration to adjust the mechanical and electrical pro...Cement and resin were designed as mixed cementitious materials to study the smart aggregate(SA)of smart concrete.Carbon fiber(CF)and surfactant were taken into consideration to adjust the mechanical and electrical properties of smart aggregate(SA)in this issue.The experimental results indicate that the flexibility and mechanical properties of SA can be improved by using such mixed cementitious materials.It is shows that,although the compressive strength and flexural strength can be enhanced effectively by using resin and CF,the electrical conductivity decreases significantly,which is because the water molecules are difficult to penetrate through the mixture materials so the hydration reaction of cement can not fully carry out.However,the electrical conductivity can be improved by adding the surfactant,and the strength and mechanical electrical properties can be adjusted effectively by the surfactant.展开更多
Electromechanical impedance (EMI) based lead zirconate titanate (PZT) is an effective sensor to ensure the safety of structure. In civil engineering community, Reinforced Concrete (RC) structure is one of the most fam...Electromechanical impedance (EMI) based lead zirconate titanate (PZT) is an effective sensor to ensure the safety of structure. In civil engineering community, Reinforced Concrete (RC) structure is one of the most familiar engineering structures. Hence, it is very important to monitor the health of structure. In this paper, a new approach of structural health monitoring using embedded PZT in host structure is proposed. There are several issues while embedding PZT inside RC structure which are examined during study. This paper presents two experimental studies on lab sized concrete beams. First implementation was carried out with different methods of embedment of PZT and its sensitivity study when the host structure was subjected to damage. The second implementation was verified in terms of conductance sensitivity of embedded Smart Aggregate (SMAG) in varying orientation i.e. horizontal (0?) and vertical (90?) after embedding in RC beam. The electrical conductance and susceptance signatures of different embedded PZT transducers were measured and damage index was calculated by using Root Mean Square Deviation Method.展开更多
Liquid migrating into existing concrete cracks is a serious problem for the reliability of concrete structures and can sometimes induce full concrete structural failures.In this paper,the authors present recent resear...Liquid migrating into existing concrete cracks is a serious problem for the reliability of concrete structures and can sometimes induce full concrete structural failures.In this paper,the authors present recent research on water presence detection in concrete cracks using piezoceramic-based smart aggregate(SA)transducers.The active sensing approach,in which one piezoceramic transducer is used to generate stress waves and others are used to detect the stress wave responses,is adopted in this research.Cracks formed in concrete structures act as stress reliefs,which attenuate the energy of the signals received by the SAs.In case of a crack being filled with liquid,which changes the wave impedance,the piezoceramic transducers will report higher received energy levels.A wavelet packet-based approach is developed to provide calculated energy values of the received signal.These different values can help detect the liquid presence in a concrete crack.A concrete beam specimen with three embedded SAs was fabricated and tested.Experimental results verified that the SA-based active sensing approach can detect a concrete crack and further detect the liquid presence in the concrete crack.展开更多
Cement mortar with carbon fiber(CFc)and resin-cement mortar with carbon fiber(CFrc)were used as inner and outer cores of smart aggregate with Z shape,respectively,which was used as the basic perception units to prepar...Cement mortar with carbon fiber(CFc)and resin-cement mortar with carbon fiber(CFrc)were used as inner and outer cores of smart aggregate with Z shape,respectively,which was used as the basic perception units to prepare smart concrete aggregate with a mosaic structure(SAMS).The hydroxpropyl methylcellulose(HPMC)was taken into consideration to improve the properties of mortar;by using HPMC,the structure of SAMS was optimized and its mechanical and electrical properties were evaluated.The experimental results show that the toughness of mortar could be improved by the complex that formed by epoxy resin,and the effect of HPMC on the flexibility of CFc was greater than that on the flexibility of CFrc;the feasible designing indicates that the CFc-Z core and CFrc-Z core could be used as inner and outer cores of SAMS.When the proposed dosages of HPMC in inner and outer cores are 0.35wt%and 0.2wt%,respectively,it could give an effective prediction for the damage of concrete during the loading process.展开更多
PD-1/PD-L1 inhibitors have emerged as standard treatments for advanced solid tumors;however,challenges such as a low overall response rate and systemic side effects impede their implementation.Hypoxia drives the remod...PD-1/PD-L1 inhibitors have emerged as standard treatments for advanced solid tumors;however,challenges such as a low overall response rate and systemic side effects impede their implementation.Hypoxia drives the remodeling of the tumor microenvironment,which is a leading reason for the failure of immunotherapies.Despite some reported strategies to alleviate hypoxia,their individual limitations constrain further improvements.Herein,a novel two-pronged strategy is pre-sented to efficiently address hypoxia by simultaneously adopting atovaquone(ATO,inhibiting oxygen consumption)and oxyhemoglobin(HbO2,directly supplement-ing oxygen)within a multifunctional aggregate termed NPs-aPD-1/HbO2/ATO.In addition to eliminating hypoxia with these two components,this smart aggre-gate also includes albumin and an ROS-responsive cross-linker as a controlled release scaffold,along with PD-1 antibody(aPD-1)for immunotherapy.Intriguingly,NPs-aPD-1/HbO2/ATO demonstrates exceptional tumor targeting in vivo,exhibit-ing≈4.2 fold higher accumulation in tumors than in the liver.Consequently,this aggregate not only effectively mitigates hypoxia and significantly assists aPD-1 immunotherapy but also simultaneously resolves the targeting and systemic toxicity issues associated with individual administration of each component.This study pro-poses substantial implications for drug-targeted delivery,addressing tumor hypoxia and advancing immunotherapy,providing valuable insights for advancing cancer treatment strategies.展开更多
基金Supported by Science and Technology Project of Ministry of Housing and Urban-Rural Development(No.2011k211)"11th Five-Year" Science and Technology Research Project of Education Department,Jilin Province(No.200925)Liaoning Structure Engineering Key Laboratory 2009 Open Fund(JG2009 2007-08)
文摘The functional piezoelectric ceramic smart aggregate(SA) sensors and actuators,based on piezoelectric ceramic materials such as lead zirconium titanate(PZT),were embedded into the reinforced concrete beams with three-point bending under static loading for purposes of damage detection.The SA actuators generated the desired sine sweep excitation signals online and the SA sensors received and detected real-time signals before and after damage.The wavelet analysis and statistical characteristics about damage signals were used as a signal processing and analysis tool to extract the optimal damage information and establish a statistical damage detection algorithm.The damage index-based wavelet analysis and damage probability-based probability and statistics were proposed by PZT wavebased theory and active health monitoring technology.The results showed that the existence of cracks inside largely attenuated the amplitude of active monitoring signal after the damage of beam and the attenuation was related to the severity degree of damage.The innovative statistical algorithm of damage pattern detection based PZT-SA can effectively determine damage probability and damage degree,and provide a prediction for the critical damage location of reinforced concrete structures.The developed method can be utilized for the structural health comprehensive monitoring and damage detection on line of various large-scale concrete structures.
基金NSC under Grant No.98-2221-E-027-057-MY2the Center for Research on Earthquake Engineering(NCREE)
文摘Structural health monitoring of RC structures under seismic loads has recently attracted much attention in the earthquake engineering research community. In this study, a piezoceramic-based device called ＂smart aggregate＂ was used for the health monitoring of RC frame structures under earthquake excitations. Three RC moment frames instrumented with smart aggregates were tested using a shaketable with different ground excitation intensities. Distributed piezoceramic- based smart aggregates were embedded in the RC structures and used to monitor their health condition during the tests. The sensitivity and effectiveness of the proposed piezoceramic-based approach were investigated and evaluated by analyzing the measured responses. The displacement ductility demand of the structural members was calculated and compared with the damage index determined from the health monitoring system. The comparison shows that the damage index is compatible with the calculated ductility demand.
基金Funded by the Natural Science Foundation of Fujian Province(No.2016J01241)the National Natural Science Foundation of China(No.51608212)the Science&Technology Pillar Program of Fujian Provincial Education Department(No.JA14024)
文摘By using redispersible polymer powder（RPP） and carbon fiber（CF） to adjust the flexibility and electrical properties of the smart aggregate, a new kind of smart aggregate with Z type structure was proposed. The study shows that Z type aggregate is more sensitive to the feedback of external force than the prism aggregate in the same loading environment, and it indicates that Z type aggregate is more suitable for the research and application of concrete health monitoring. Although the incorporation of RPP would cause the compressive strength of the aggregates and the elastic modulus of hardened cement mortar to reduce slightly within the dosage of RPP by 2.25% because of the polymer film formed in the internal system, this would improve the deformability of the aggregates. In the early loading stage（in the first 60 seconds）, the intelligent concrete specimens implanted with Z type smart aggregate do not show higher sensitivity as expected, although the resistance change rate changes a little bit more, the overall of it is still in balance. Adding RPP could improve the flexibility of smart aggregates exactly, and it plays an active role in prolonging the life of the smart aggregates. By implanting Z type aggregates the damage and failure of the concrete structure could be predicted accurately in this study. The results of this paper will help to promote further research and application of intelligent concrete.
文摘The most familiar civil engineering structure is reinforced concrete (RC) structure. Performance of structure undergoes changes during their service life with time. Thus, it is of great concern to monitor the health of RC structure. Structural health monitoring (SHM) is the art of detecting the changes in structure that influences its performance. Various techniques to monitor the health of structure are broadly studied worldwide. PZT based smart aggregate can play an effective role as an advanced tool in the development of structural health monitoring. This research work contributes for proposing a more generous Non-Destructive Evaluation (NDE) technique for structural health monitoring by using smart materials. If performance of a structure deviates from the design parameters with time, appropriate and effective maintenance is required. Considering the relevant need of RC structures, a more sensitive and cost-effective approach by using Electro-Mechanical Impedance (EMI) technique has been proposed for implementation in real-life situations. In general, surface bonded PZT transducer is used for SHM. Since PZT transducers are of very small dimension and brittle in nature, for consistent characteristics, they should be protected from severe environmental condition and other external interruptions. For this reason, PZT transducer is embedded in structure at the time of construction and manufacturing of the embedded transducer is simple. The proposed EMI technique assesses the health of RC structures more rationally by embedding PZT transducer in the structure, whose health is to be monitored over the user specified preset frequency range. The conductance and susceptance signatures are acquired by using LCR meter. At any future point of time, when it is desired to assess the health of structure, the conductance and susceptance signatures are acquired and further utilized for damage detection and quantification. The Root Mean Square Deviation (RMSD) is used to specify damage severity.
基金Funded by the Natural Science Foundation of Fujian Province(No.2016J01241)the National Natural Science Foundation of China(No.52178484)the Education Department of Fujian Province(No.JA14024)。
文摘Cement and resin were designed as mixed cementitious materials to study the smart aggregate(SA)of smart concrete.Carbon fiber(CF)and surfactant were taken into consideration to adjust the mechanical and electrical properties of smart aggregate(SA)in this issue.The experimental results indicate that the flexibility and mechanical properties of SA can be improved by using such mixed cementitious materials.It is shows that,although the compressive strength and flexural strength can be enhanced effectively by using resin and CF,the electrical conductivity decreases significantly,which is because the water molecules are difficult to penetrate through the mixture materials so the hydration reaction of cement can not fully carry out.However,the electrical conductivity can be improved by adding the surfactant,and the strength and mechanical electrical properties can be adjusted effectively by the surfactant.
文摘Electromechanical impedance (EMI) based lead zirconate titanate (PZT) is an effective sensor to ensure the safety of structure. In civil engineering community, Reinforced Concrete (RC) structure is one of the most familiar engineering structures. Hence, it is very important to monitor the health of structure. In this paper, a new approach of structural health monitoring using embedded PZT in host structure is proposed. There are several issues while embedding PZT inside RC structure which are examined during study. This paper presents two experimental studies on lab sized concrete beams. First implementation was carried out with different methods of embedment of PZT and its sensitivity study when the host structure was subjected to damage. The second implementation was verified in terms of conductance sensitivity of embedded Smart Aggregate (SMAG) in varying orientation i.e. horizontal (0?) and vertical (90?) after embedding in RC beam. The electrical conductance and susceptance signatures of different embedded PZT transducers were measured and damage index was calculated by using Root Mean Square Deviation Method.
基金partially supported by the Science Fund for Creative Research Groups under Grant No.[51121005]a research project under Grant No.[51278084]from the National Science Foundation of China.
文摘Liquid migrating into existing concrete cracks is a serious problem for the reliability of concrete structures and can sometimes induce full concrete structural failures.In this paper,the authors present recent research on water presence detection in concrete cracks using piezoceramic-based smart aggregate(SA)transducers.The active sensing approach,in which one piezoceramic transducer is used to generate stress waves and others are used to detect the stress wave responses,is adopted in this research.Cracks formed in concrete structures act as stress reliefs,which attenuate the energy of the signals received by the SAs.In case of a crack being filled with liquid,which changes the wave impedance,the piezoceramic transducers will report higher received energy levels.A wavelet packet-based approach is developed to provide calculated energy values of the received signal.These different values can help detect the liquid presence in a concrete crack.A concrete beam specimen with three embedded SAs was fabricated and tested.Experimental results verified that the SA-based active sensing approach can detect a concrete crack and further detect the liquid presence in the concrete crack.
基金Funded by the Natural Science Foundation of Fujian Province(No.2016J01241)the National Natural Science Foundation of China(No.51608212)。
文摘Cement mortar with carbon fiber(CFc)and resin-cement mortar with carbon fiber(CFrc)were used as inner and outer cores of smart aggregate with Z shape,respectively,which was used as the basic perception units to prepare smart concrete aggregate with a mosaic structure(SAMS).The hydroxpropyl methylcellulose(HPMC)was taken into consideration to improve the properties of mortar;by using HPMC,the structure of SAMS was optimized and its mechanical and electrical properties were evaluated.The experimental results show that the toughness of mortar could be improved by the complex that formed by epoxy resin,and the effect of HPMC on the flexibility of CFc was greater than that on the flexibility of CFrc;the feasible designing indicates that the CFc-Z core and CFrc-Z core could be used as inner and outer cores of SAMS.When the proposed dosages of HPMC in inner and outer cores are 0.35wt%and 0.2wt%,respectively,it could give an effective prediction for the damage of concrete during the loading process.
基金supported by the National Natural Science Foundation of China(Nos.82073058,32371449)Basic Research Projects of the Natural Science Foundation of Shaanxi Province(key program)(2021JZ-37)+2 种基金Youth Cultivation Project of the First Affiliated Hospital of Xi’an Jiaotong University(No.2019QN-02)Nanjing Tianqing Research Fund Project(No.HX202324)the Clinical Research Award of the First Affiliated Hospital of Xi’an Jiaotong University,China(No.XJTU1AF-CRF-2022-009).
文摘PD-1/PD-L1 inhibitors have emerged as standard treatments for advanced solid tumors;however,challenges such as a low overall response rate and systemic side effects impede their implementation.Hypoxia drives the remodeling of the tumor microenvironment,which is a leading reason for the failure of immunotherapies.Despite some reported strategies to alleviate hypoxia,their individual limitations constrain further improvements.Herein,a novel two-pronged strategy is pre-sented to efficiently address hypoxia by simultaneously adopting atovaquone(ATO,inhibiting oxygen consumption)and oxyhemoglobin(HbO2,directly supplement-ing oxygen)within a multifunctional aggregate termed NPs-aPD-1/HbO2/ATO.In addition to eliminating hypoxia with these two components,this smart aggre-gate also includes albumin and an ROS-responsive cross-linker as a controlled release scaffold,along with PD-1 antibody(aPD-1)for immunotherapy.Intriguingly,NPs-aPD-1/HbO2/ATO demonstrates exceptional tumor targeting in vivo,exhibit-ing≈4.2 fold higher accumulation in tumors than in the liver.Consequently,this aggregate not only effectively mitigates hypoxia and significantly assists aPD-1 immunotherapy but also simultaneously resolves the targeting and systemic toxicity issues associated with individual administration of each component.This study pro-poses substantial implications for drug-targeted delivery,addressing tumor hypoxia and advancing immunotherapy,providing valuable insights for advancing cancer treatment strategies.
