Due to the existence of the attached mortar,the performance of the recycled concrete aggregate(RCA)is inferior to the natural aggregate,which significantly limits its wide application in industry.In this study,five ki...Due to the existence of the attached mortar,the performance of the recycled concrete aggregate(RCA)is inferior to the natural aggregate,which significantly limits its wide application in industry.In this study,five kinds of modified solutions were used to modify the surface of RCA,and the modification effects were compared.The results showed that sodium silicate,nano-silica(NS),Bacillus pasteurii and soybean powder had relatively good modification effects on RCA,which could reduce the crushing value and water absorption,and increase apparent density.The composite solution(15%sodium silicate and 2%NS)and soybean powder solution had better modification effect.The 28 d compressive strength and splitting tensile strength of recycled aggregate concrete(RAC)prepared by RCA modified by soybean powder solution were 4.6%and 5.2%higher than those prepared by RCA modified by composite solution,respectively.This indicates that among the five kinds of modified solutions,soybean powder solution has the best modification effect on RCA,and the optimal soaking time of soybean powder solution is 8 h.At this time,the crushing value,water absorption and apparent density of RCA are 12.8%,5.3%,and 2653 kg/m^(3),respectively.The research results of this study provide a reference for the modification of RCA and its efficient utilization.展开更多
This paper has solved the Chester modified heat conduction equation of the different relaxation time r value under different temperature conditions, different boundary conditions and the different initial conditions b...This paper has solved the Chester modified heat conduction equation of the different relaxation time r value under different temperature conditions, different boundary conditions and the different initial conditions by different means of methods. These solutions can help to obtain temperature field of laser thermal effects.展开更多
The paper presents a flow plasma reactor permitting modification of the properties of water/aqueous solutions by stochastic resonance amplification of vibrations of selected chemical species in water with electromagne...The paper presents a flow plasma reactor permitting modification of the properties of water/aqueous solutions by stochastic resonance amplification of vibrations of selected chemical species in water with electromagnetic noise generated during a plasma discharge. The main parameters characterizing the quality for super-pure water, tap water and water from the intake in Besko (Poland) before and after the process in the plasma reactor were presented for comparison. In addition, the <sup>17</sup>O NMR (the full width at half maximum) and electrospray ionization mass spectrometry (ESI MS) methods were used to determine differences in physicochemical parameters between the untreated and plasma-treated water. It has been established that the water subjected to plasma treatment shows much different gas absorption properties than the untreated water samples, as a function of temperature and pressure, in this paper we report exemplary data for CO<sub>2</sub>, oxygen and acetylene. The improved gas absorption properties of the plasma-treated water make it attractive for the use in industrial processes. It is worth pointing to a great capacity of the new reactor (4000 l/h), and low energy consumption (20 MJ/h) for the treatment of the above mentioned volume flow rate of water.展开更多
基金the financial support of National Key R&D Program of China(No.2019YFC1906200)the National Natural Science Foundation of China(Nos.51879093,51009057 and 52108206)+1 种基金Jiangsu Science and Technology Department of China(No.BE2015706)Science and Technology Project of Nanjing Water Authority(No.201802).
文摘Due to the existence of the attached mortar,the performance of the recycled concrete aggregate(RCA)is inferior to the natural aggregate,which significantly limits its wide application in industry.In this study,five kinds of modified solutions were used to modify the surface of RCA,and the modification effects were compared.The results showed that sodium silicate,nano-silica(NS),Bacillus pasteurii and soybean powder had relatively good modification effects on RCA,which could reduce the crushing value and water absorption,and increase apparent density.The composite solution(15%sodium silicate and 2%NS)and soybean powder solution had better modification effect.The 28 d compressive strength and splitting tensile strength of recycled aggregate concrete(RAC)prepared by RCA modified by soybean powder solution were 4.6%and 5.2%higher than those prepared by RCA modified by composite solution,respectively.This indicates that among the five kinds of modified solutions,soybean powder solution has the best modification effect on RCA,and the optimal soaking time of soybean powder solution is 8 h.At this time,the crushing value,water absorption and apparent density of RCA are 12.8%,5.3%,and 2653 kg/m^(3),respectively.The research results of this study provide a reference for the modification of RCA and its efficient utilization.
基金This work was supported by the National Natural Science Foundation of China(No.60068001)and the Natural Science Foundation of Yunnan Province(No.2000A0021M)and ESF of Yunnan(No.0111054).
文摘This paper has solved the Chester modified heat conduction equation of the different relaxation time r value under different temperature conditions, different boundary conditions and the different initial conditions by different means of methods. These solutions can help to obtain temperature field of laser thermal effects.
文摘The paper presents a flow plasma reactor permitting modification of the properties of water/aqueous solutions by stochastic resonance amplification of vibrations of selected chemical species in water with electromagnetic noise generated during a plasma discharge. The main parameters characterizing the quality for super-pure water, tap water and water from the intake in Besko (Poland) before and after the process in the plasma reactor were presented for comparison. In addition, the <sup>17</sup>O NMR (the full width at half maximum) and electrospray ionization mass spectrometry (ESI MS) methods were used to determine differences in physicochemical parameters between the untreated and plasma-treated water. It has been established that the water subjected to plasma treatment shows much different gas absorption properties than the untreated water samples, as a function of temperature and pressure, in this paper we report exemplary data for CO<sub>2</sub>, oxygen and acetylene. The improved gas absorption properties of the plasma-treated water make it attractive for the use in industrial processes. It is worth pointing to a great capacity of the new reactor (4000 l/h), and low energy consumption (20 MJ/h) for the treatment of the above mentioned volume flow rate of water.
