This paper presents a brief introduction about the preliminary consulting and tender agent of Canton Tower,the basic situation of the whole-process supervision on the construction site,and a general summary of the Can...This paper presents a brief introduction about the preliminary consulting and tender agent of Canton Tower,the basic situation of the whole-process supervision on the construction site,and a general summary of the Canton Tower project management.What's more,the author suggests that some guidelines be formed for supervision enterprises involved in large-scale project management.展开更多
Ammonia(NH_(3))is a key precursor of fine particulate matter(PM_(2.5))in the air;however,its emission sources at different heights remain poorly understood in the Pearl River Delta(PRD)region of China.In this study,we...Ammonia(NH_(3))is a key precursor of fine particulate matter(PM_(2.5))in the air;however,its emission sources at different heights remain poorly understood in the Pearl River Delta(PRD)region of China.In this study,we simultaneously collected PM_(2.5)samples at three atmospheric heights(ground,118 m,and 488 m)based on the atmospheric observatories of Canton Tower,the tallest structure in the PRD region.Our results showed that the average NH_(4)+concentrations were 2.7±1.4,3.0±1.8,and 2.6±1.7μg/m3 at the ground site,118 m,and 488 m during the sampling campaign,with no significant difference(p>0.05)among the three heights.However,the stable nitrogen isotope composition values in NH_(4)+(δ15N-NH_(4)+)displayed a significant correlation with height(p<0.05).We further calculated the initialδ15N-NH_(3)values and performed source apportionments using the Bayesian Isotope Mixture Model.The results indicated that the mean contributions of agriculture,waste,vehicle,biomass burning,NH_(3)slip,and coal combustion were 9.9%±4.4%,8.3%±5.5%,29%±8.0%,16%±2.2%,25%±6.0%,and 12%±3.4%,respectively,at the ground site during the sampling campaign.By contrast,the contributions of sources at 488 m remained relatively stable due to the limited influence of local activities.Overall,our study highlights the dominant role of combustion sources in NH_(3)emissions in the PRD region,with their contribution being highly dependent on atmospheric height.展开更多
This paper presents an effective approach for updating finite element dynamic model from incomplete modal data identified from ambient vibration measurements.The proposed method is based on the relationship between th...This paper presents an effective approach for updating finite element dynamic model from incomplete modal data identified from ambient vibration measurements.The proposed method is based on the relationship between the perturbation of structural parameters such as stiffness and mass changes and the modal data measurements of the tested structure such as measured mode shape readings.Structural updating parameters including both stiffness and mass parameters are employed to represent the differences in structural parameters between the finite element model and the associated tested structure.These updating parameters are then evaluated by an iterative solution procedure,giving optimised solutions in the least squares sense without requiring an optimisation technique.In order to reduce the influence of modal measurement uncertainty,the truncated singular value decomposition regularization method incorporating the quasi-optimality criterion is employed to produce reliable solutions for the structural updating parameters.Finally,the numerical investigations of a space frame structure and the practical applications to the Canton Tower benchmark problem demonstrate that the proposed method can correctly update the given finite element model using the incomplete modal data identified from the recorded ambient vibration measurements.展开更多
文摘This paper presents a brief introduction about the preliminary consulting and tender agent of Canton Tower,the basic situation of the whole-process supervision on the construction site,and a general summary of the Canton Tower project management.What's more,the author suggests that some guidelines be formed for supervision enterprises involved in large-scale project management.
基金supported by the National Natural Science Foundation of China(No.42230602)the National Key Research and Development Program of China(No.2022YFC3700602)the Guang Dong Basic and Applied Basic Research Foundation(China)(No.2024B1515040026).
文摘Ammonia(NH_(3))is a key precursor of fine particulate matter(PM_(2.5))in the air;however,its emission sources at different heights remain poorly understood in the Pearl River Delta(PRD)region of China.In this study,we simultaneously collected PM_(2.5)samples at three atmospheric heights(ground,118 m,and 488 m)based on the atmospheric observatories of Canton Tower,the tallest structure in the PRD region.Our results showed that the average NH_(4)+concentrations were 2.7±1.4,3.0±1.8,and 2.6±1.7μg/m3 at the ground site,118 m,and 488 m during the sampling campaign,with no significant difference(p>0.05)among the three heights.However,the stable nitrogen isotope composition values in NH_(4)+(δ15N-NH_(4)+)displayed a significant correlation with height(p<0.05).We further calculated the initialδ15N-NH_(3)values and performed source apportionments using the Bayesian Isotope Mixture Model.The results indicated that the mean contributions of agriculture,waste,vehicle,biomass burning,NH_(3)slip,and coal combustion were 9.9%±4.4%,8.3%±5.5%,29%±8.0%,16%±2.2%,25%±6.0%,and 12%±3.4%,respectively,at the ground site during the sampling campaign.By contrast,the contributions of sources at 488 m remained relatively stable due to the limited influence of local activities.Overall,our study highlights the dominant role of combustion sources in NH_(3)emissions in the PRD region,with their contribution being highly dependent on atmospheric height.
文摘This paper presents an effective approach for updating finite element dynamic model from incomplete modal data identified from ambient vibration measurements.The proposed method is based on the relationship between the perturbation of structural parameters such as stiffness and mass changes and the modal data measurements of the tested structure such as measured mode shape readings.Structural updating parameters including both stiffness and mass parameters are employed to represent the differences in structural parameters between the finite element model and the associated tested structure.These updating parameters are then evaluated by an iterative solution procedure,giving optimised solutions in the least squares sense without requiring an optimisation technique.In order to reduce the influence of modal measurement uncertainty,the truncated singular value decomposition regularization method incorporating the quasi-optimality criterion is employed to produce reliable solutions for the structural updating parameters.Finally,the numerical investigations of a space frame structure and the practical applications to the Canton Tower benchmark problem demonstrate that the proposed method can correctly update the given finite element model using the incomplete modal data identified from the recorded ambient vibration measurements.
