For phosphorus （P） recovery from wastewater, the effect of humic substances （HS） on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with syn...For phosphorus （P） recovery from wastewater, the effect of humic substances （HS） on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate （as P） and 20 mg/L HS （as dissolved organic carbon, DOC） at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium （Ca） and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction （XRD） and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0, the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite （HAP） by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate.展开更多
A set of fountain solution system is designed, which can automatically adjust the concentration, pH value, temperature of the fountain solution in the printing process to ensure that the fountain solution system mixes...A set of fountain solution system is designed, which can automatically adjust the concentration, pH value, temperature of the fountain solution in the printing process to ensure that the fountain solution system mixes stable and qualified fountain solution and maintains a good balance of ink and water, thus improving the quality of printed products. The structure of the new fountain solution system mainly comprises a water inlet and medicine inlet system, a water tank circulation system, a water bucket and collection tank system, a refrigeration circulation system, a temperature control system and an automatic pH value detection and adjustment system of the fountain solution. The working flow and electrical control principle of the fountain solution system are described in detail. This paper focuses on the automatic detection and adjustment system of pH value of fountain solution, including the analysis of the control principle and process of the adjustment system, and the design and research of the pH master control system circuit and pH electrode signal measurement circuit.展开更多
To obtain the design parameters of the structure made by ecological high ductility cementitious composites(Eco-HDCC),the effects of curing age on the compressive and tensile stress-strain relationships were studied.Th...To obtain the design parameters of the structure made by ecological high ductility cementitious composites(Eco-HDCC),the effects of curing age on the compressive and tensile stress-strain relationships were studied.The reaction degree of fly ash,non-evaporable water content and the pH value in pore solution were calculated to reveal the mechanical property.The results indicate that as the curing age increases,the peak compressive strength,peak compressive strain and ultimate tensile strength of Eco-HDCC increase.However,the ultimate compressive strain and ultimate tensile strain of Eco-HDCC decrease with the increase in curing age.Besides,as the curing age increases,the reaction degree of fly ash and non-evaporable water content in Eco-HDCC increase,while the pH value in the pore solution of Eco-HDCC decreases.Finally,the simplified compressive and tensile stress-strain constitutive relationship models of Eco-HDCC with a curing age of 28 d were suggested for the structure design safety.展开更多
基金The German Research Foundation (DFG-Graduiertenkolleg 366) Grant Program for the High-Level Returned Scholars fromAbroad, Ministry of Personnel of China (No. 2004-2005)
文摘For phosphorus （P） recovery from wastewater, the effect of humic substances （HS） on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate （as P） and 20 mg/L HS （as dissolved organic carbon, DOC） at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium （Ca） and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction （XRD） and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0, the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite （HAP） by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate.
文摘A set of fountain solution system is designed, which can automatically adjust the concentration, pH value, temperature of the fountain solution in the printing process to ensure that the fountain solution system mixes stable and qualified fountain solution and maintains a good balance of ink and water, thus improving the quality of printed products. The structure of the new fountain solution system mainly comprises a water inlet and medicine inlet system, a water tank circulation system, a water bucket and collection tank system, a refrigeration circulation system, a temperature control system and an automatic pH value detection and adjustment system of the fountain solution. The working flow and electrical control principle of the fountain solution system are described in detail. This paper focuses on the automatic detection and adjustment system of pH value of fountain solution, including the analysis of the control principle and process of the adjustment system, and the design and research of the pH master control system circuit and pH electrode signal measurement circuit.
基金The National Natural Science Foundations of China(No.51778133)the Transportation Science&Technology Project of Fujian Province(No.2017Y057)+1 种基金the China Railway Project(No.2017G007-C)Foundation of the China Scholarship Council(No.201906090163).
文摘To obtain the design parameters of the structure made by ecological high ductility cementitious composites(Eco-HDCC),the effects of curing age on the compressive and tensile stress-strain relationships were studied.The reaction degree of fly ash,non-evaporable water content and the pH value in pore solution were calculated to reveal the mechanical property.The results indicate that as the curing age increases,the peak compressive strength,peak compressive strain and ultimate tensile strength of Eco-HDCC increase.However,the ultimate compressive strain and ultimate tensile strain of Eco-HDCC decrease with the increase in curing age.Besides,as the curing age increases,the reaction degree of fly ash and non-evaporable water content in Eco-HDCC increase,while the pH value in the pore solution of Eco-HDCC decreases.Finally,the simplified compressive and tensile stress-strain constitutive relationship models of Eco-HDCC with a curing age of 28 d were suggested for the structure design safety.
