Two carbonation approaches are considered for studying the effects on the hardening mechanisms of slurries made of 100 wt%electric arc furnace steel slag (EAF) slag or 80 wt%EAF slag incorporating 20 wt% of Portland c...Two carbonation approaches are considered for studying the effects on the hardening mechanisms of slurries made of 100 wt%electric arc furnace steel slag (EAF) slag or 80 wt%EAF slag incorporating 20 wt% of Portland cement,which are applied during the hot-stage pretreatment with simulated gas for raw steel slag or the accelerated carbonation curing of slurry.The mechanical strengths,carbonate products,microstructures and CO_(2) uptakes were quantitatively investigated.Results manifest that accelerated carbonation curing increases the compressive strengths of steel slag slurry,from 17.1 MPa (binder of 80 wt% EAF and 20 wt%cement under standard moisture curing) to 36.0 MPa (binder of 80 wt%EAF and 20 wt%cement under accelerated carbonation curing),with a CO_(2) uptake of 52%.In contrast,hot-stage carbonation applied during the pretreatment of steel slag increases the compressive strengths to 43.7 MPa (binder of 80 wt%carbonated EAF and 20 wt%cement under accelerated carbonation curing),with a CO_(2) uptake of 67%.Hotstage carbonation of steel slag is found for particle agglomeration,minerals remodeling and calcite formed,thus causing an activated steel slag with a dense structure and more active components.Accelerated carbonation curing of steel slag slurry paste results in the newly formed amorphous CaCO_(3),calcite crystalline and silica gels that covered the pores of the matrix,facilitating microstructure densification and strength improvement.Adopting the combinative methods of the hot-stage CO_(2) pretreatment and accelerated carbonation curing creates a promising high-volume steel slag-based binder with high strengths and CO_(2) storage.展开更多
Purpose-This paper aims to analyze the bearing characteristics of the high speed train window glass under aerodynamic load effects.Design/methodology/approach-In order to obtain the dynamic strain response of passenge...Purpose-This paper aims to analyze the bearing characteristics of the high speed train window glass under aerodynamic load effects.Design/methodology/approach-In order to obtain the dynamic strain response of passenger compartment window glass during high-speed train crossing the tunnel,taking the passenger compartment window glass of the CRH3 high speed train onWuhan-Guangzhou High Speed Railway as the research object,this study tests the strain dynamic response and maximum principal stress of the high speed train passing through the tunnel entrance and exit,the tunnel and tunnel groups as well as trains meeting in the tunnel at an average speed of 300 km$h-1.Findings-The results show that while crossing the tunnel,the passenger compartment window glass of high speed train is subjected to the alternating action of positive and negative air pressures,which shows the typical mechanic characteristics of the alternating fatigue stress of positive-negative transient strain.The maximum principal stress of passenger compartment window glass for high speed train caused by tunnel aerodynamic effects does not exceed 5 MPa,and the maximum value occurs at the corresponding time of crossing the tunnel groups.The high speed train window glass bears medium and low strain rates under the action of tunnel aerodynamic effects,while the maximum strain rate occurs at the meeting moment when the window glass meets the train head approaching from the opposite side in the tunnel.The shear modulus of laminated glass PVB film that makes up high speed train window glass is sensitive to the temperature and action time.The dynamically equivalent thickness and stiffness of the laminated glass and the dynamic bearing capacity of the window glass decrease with the increase of the action time under tunnel aerodynamic pressure.Thus,the influence of the loading action time and fatigue under tunnel aerodynamic effects on the glass strength should be considered in the design for the bearing performance of high speed train window glass.Originality/value-The research results provide data support for the analysis of mechanical characteristics,damage mechanism,strength design and structural optimization of high speed train glass.展开更多
Hazardous waste of chemical oxygen demand (COD) test (HWCOD) is one of the most common laboratory wastewaters,containing large amounts of H_(2)SO_(4)and highly toxic Cr^(3+)and Hg^(2+).Current treatment methods suffer...Hazardous waste of chemical oxygen demand (COD) test (HWCOD) is one of the most common laboratory wastewaters,containing large amounts of H_(2)SO_(4)and highly toxic Cr^(3+)and Hg^(2+).Current treatment methods suffered from incomplete removal of Cr^(3+)and high-cost.Herein,a humic acid-coated zirconium oxide-resin nanocomposite (HA-HZO-201) was fabricated for efficient recovery of Cr^(3+)and Hg^(2+)in HWCOD.The synthesized HA-HZO-201 shows excellent tolerance to wide p H range (1–5) and high salinity (3.5 mol/L Na Cl),as well as adsorption capacity for Cr^(3+)(37.5 mg/g) and Hg^(2+)(121.3 mg/g).After treating with HA-HZO-201 by using a fixed-bed adsorption procedure,the final Cr^(3+)and Hg^(2+)concentrations in HWCOD decreased to 0.28 and 0.02 mg/L,respectively.In addition,the HA-HZO-201 can be regenerated by desorption and recovery of Cr^(3+)and Hg^(2+)using HNO_(3)and thiourea as eluents,respectively.After 5 cycles of adsorption/desorption,the removal efficiencies still reach up to86.0%for Cr^(3+)and 89.7%for Hg^(2+),indicating an excellent regeneration of HA-HZO-201.We hope this work open new opportunities for treatment of HWCODwith high-efficiency and low-cost.展开更多
基金Funded by the National Key Research and Development Program of China-Intergovernmental International Cooperation in Scientific and Technological Innovation MOST,China (No.2018YFE0107300)。
文摘Two carbonation approaches are considered for studying the effects on the hardening mechanisms of slurries made of 100 wt%electric arc furnace steel slag (EAF) slag or 80 wt%EAF slag incorporating 20 wt% of Portland cement,which are applied during the hot-stage pretreatment with simulated gas for raw steel slag or the accelerated carbonation curing of slurry.The mechanical strengths,carbonate products,microstructures and CO_(2) uptakes were quantitatively investigated.Results manifest that accelerated carbonation curing increases the compressive strengths of steel slag slurry,from 17.1 MPa (binder of 80 wt% EAF and 20 wt%cement under standard moisture curing) to 36.0 MPa (binder of 80 wt%EAF and 20 wt%cement under accelerated carbonation curing),with a CO_(2) uptake of 52%.In contrast,hot-stage carbonation applied during the pretreatment of steel slag increases the compressive strengths to 43.7 MPa (binder of 80 wt%carbonated EAF and 20 wt%cement under accelerated carbonation curing),with a CO_(2) uptake of 67%.Hotstage carbonation of steel slag is found for particle agglomeration,minerals remodeling and calcite formed,thus causing an activated steel slag with a dense structure and more active components.Accelerated carbonation curing of steel slag slurry paste results in the newly formed amorphous CaCO_(3),calcite crystalline and silica gels that covered the pores of the matrix,facilitating microstructure densification and strength improvement.Adopting the combinative methods of the hot-stage CO_(2) pretreatment and accelerated carbonation curing creates a promising high-volume steel slag-based binder with high strengths and CO_(2) storage.
基金supported by the National Natural Science Foundation of China (Grant Nos.52072356 and 52032011)the 2019 Zaozhuang High-level Talents Project (Grant No.ZZYF-01).
文摘Purpose-This paper aims to analyze the bearing characteristics of the high speed train window glass under aerodynamic load effects.Design/methodology/approach-In order to obtain the dynamic strain response of passenger compartment window glass during high-speed train crossing the tunnel,taking the passenger compartment window glass of the CRH3 high speed train onWuhan-Guangzhou High Speed Railway as the research object,this study tests the strain dynamic response and maximum principal stress of the high speed train passing through the tunnel entrance and exit,the tunnel and tunnel groups as well as trains meeting in the tunnel at an average speed of 300 km$h-1.Findings-The results show that while crossing the tunnel,the passenger compartment window glass of high speed train is subjected to the alternating action of positive and negative air pressures,which shows the typical mechanic characteristics of the alternating fatigue stress of positive-negative transient strain.The maximum principal stress of passenger compartment window glass for high speed train caused by tunnel aerodynamic effects does not exceed 5 MPa,and the maximum value occurs at the corresponding time of crossing the tunnel groups.The high speed train window glass bears medium and low strain rates under the action of tunnel aerodynamic effects,while the maximum strain rate occurs at the meeting moment when the window glass meets the train head approaching from the opposite side in the tunnel.The shear modulus of laminated glass PVB film that makes up high speed train window glass is sensitive to the temperature and action time.The dynamically equivalent thickness and stiffness of the laminated glass and the dynamic bearing capacity of the window glass decrease with the increase of the action time under tunnel aerodynamic pressure.Thus,the influence of the loading action time and fatigue under tunnel aerodynamic effects on the glass strength should be considered in the design for the bearing performance of high speed train window glass.Originality/value-The research results provide data support for the analysis of mechanical characteristics,damage mechanism,strength design and structural optimization of high speed train glass.
基金supported by the National Natural Science Foundation of China(Nos.22106028,22076198)the China Postdoctoral Science Foundation (No.2021M703406)。
文摘Hazardous waste of chemical oxygen demand (COD) test (HWCOD) is one of the most common laboratory wastewaters,containing large amounts of H_(2)SO_(4)and highly toxic Cr^(3+)and Hg^(2+).Current treatment methods suffered from incomplete removal of Cr^(3+)and high-cost.Herein,a humic acid-coated zirconium oxide-resin nanocomposite (HA-HZO-201) was fabricated for efficient recovery of Cr^(3+)and Hg^(2+)in HWCOD.The synthesized HA-HZO-201 shows excellent tolerance to wide p H range (1–5) and high salinity (3.5 mol/L Na Cl),as well as adsorption capacity for Cr^(3+)(37.5 mg/g) and Hg^(2+)(121.3 mg/g).After treating with HA-HZO-201 by using a fixed-bed adsorption procedure,the final Cr^(3+)and Hg^(2+)concentrations in HWCOD decreased to 0.28 and 0.02 mg/L,respectively.In addition,the HA-HZO-201 can be regenerated by desorption and recovery of Cr^(3+)and Hg^(2+)using HNO_(3)and thiourea as eluents,respectively.After 5 cycles of adsorption/desorption,the removal efficiencies still reach up to86.0%for Cr^(3+)and 89.7%for Hg^(2+),indicating an excellent regeneration of HA-HZO-201.We hope this work open new opportunities for treatment of HWCODwith high-efficiency and low-cost.
