To solve the problem of only surface carbonation and realize high-efficiency carbonation of recycled coarse aggregate,the method of carbonated recycled coarse aggregate with nano materials pre-soaking was first put fo...To solve the problem of only surface carbonation and realize high-efficiency carbonation of recycled coarse aggregate,the method of carbonated recycled coarse aggregate with nano materials pre-soaking was first put forward.The carbonation effect of modified recycled coarse aggregate with three different carbonation methods was evaluated,and water absorption,apparent density and crush index of modified recycled coarse aggregate were measured.Combined with XRD,SEM,and MIP microscopic analysis,the high-efficiency carbonation strengthening mechanism of modified recycled coarse aggregate was revealed.The experimental results show that,compared with the non-carbonated recycled coarse aggregate,the physical and microscopic properties of carbonated recycled coarse aggregate are improved.The method of carbonation with nano-SiO_(2) pre-soaking can realize the high-efficiency carbonation of recycled coarse aggregate,for modified recycled coarse aggregate with the method,water absorption is reduced by 23.03%,porosity is reduced by 44.06%,and the average pore diameter is 21.82 nm.The high-efficiency carbonation strengthening mechanism show that the pre-socked nano-SiO_(2) is bound to the hydration product Ca(OH)_(2) of the old mortar with nano-scale C-S-H,which can improve the CO_(2) absorption rate,accelerate the carbonation reaction,generate more stable CaCO_(3) and nano-scale silica gel,and bond to the dense three-dimensional network structure to realize the bidirectional enhancement of nano-materials and pressurized carbonation.It is concluded that the method of carbonation with nano-SiO_(2) pre-soaking is a novel high-efficiency carbonation modification of recycled coarse aggregate.展开更多
Low critical temperature limits the application of CO_2 trans-critical power cycle.The binary mixture of R290/CO_2has higher critical temperature.Using mixture fluid may solve the problem that subcritical CO_2 is hard...Low critical temperature limits the application of CO_2 trans-critical power cycle.The binary mixture of R290/CO_2has higher critical temperature.Using mixture fluid may solve the problem that subcritical CO_2 is hardly condensed by conventional cooling water.In this article,theoretical analysis is executed to study the performance of the zeotropic mixture for trans-critical power cycle using low-grade liquid heat source with temperature of200℃.The results indicated that the problem that CO_2 can't be condensed in power cycle by conventional cooling water can be solved by mixing R290 to CO_2.Variation trend of outlet temperature of thermal oil in supercritical heater with heating pressure is determined by the composition of the mixture fluid.Gliding temperature causes the maximum outlet temperature of cooling water with the increase of mass fraction of R290.There are the maximum values for cycle thermal efficiency and net power output with the increase of supercritical heating pressure.展开更多
Dining lampblack as a source of atmospheric pollution,urban residents had to spend a lot of economic costs all year round to solve its impact.However,traditional treatment methods often carry the risk of secondary pol...Dining lampblack as a source of atmospheric pollution,urban residents had to spend a lot of economic costs all year round to solve its impact.However,traditional treatment methods often carry the risk of secondary pollution.The use of phase change absorption solvent(PCAS)controlled by CO_(2)can effectively absorb the oily components in dining lampblack,and smoothly avoid the generation of secondary pollutants and squandering of resources.The reversibility of PCASs under CO_(2)control was explained by pH changes and macroscopic visualizations.The absorption effects of favorable absorbents and PCASs on dining lampblack were compared and analyzed.The fatty acid(FA)in the oil absorption mixture was desorbed by interacting with D230.The results of GC/MS analysis on the oil components separated by desorption showed that the desorption of PCASs was effective for these refractory oil components.FAs can be enriched and applied to the subsequent dining lampblack treatment link to realize the waste recycling.In addition,the absorption and desorption of oily components by PCASs were combined with the CO_(2)-controlled phase transformation of PCASs itself to achieve the absorption circulation of treating dining lampblack by using PCASs.展开更多
This paper investigates the effect of recycled polyester fiber, produced from polyethylene （PET） bottles, in combination with nano-SiO2 as a new stabilizer to improve the mechanical properties of soils. We intend to...This paper investigates the effect of recycled polyester fiber, produced from polyethylene （PET） bottles, in combination with nano-SiO2 as a new stabilizer to improve the mechanical properties of soils. We intend to study the effect of adding nano-SiO2 and recycled polyester fiber on soil engineering properties, especially the shear strength and unconfined compressive strength （UCS）, using clayey soil with low liquid limit. Three different combinations of fiber-soil ratios ranging between 0.1% and 0.5% as well as three different combinations of nano-soil ratios ranging between 0.5% and 1% are used. The shear strength and UCS of treated specimens are obtained from direct shear test and unconfined compression test, respectively. Results of this study show that the addition of recycled polyester fiber and nano-SiO2 increases the strength of soil specimens. Both the shear strength and UCS are improved by increasing the contents of recycled polyester fiber and nano-SiO2 in the soil mixture. The increase in the nano-SiO2 content leads to a reduction in failure strain, but the increase in the content of recycled polyester fiber leads to an increase in failure strain. The increase in the contents of recycled polyester fiber and nano-SiO2 leads to an increase in elastic modulus of soils. Based on the test results, the addition of recycled polyester fiber improves the mechanical properties of soils stabilized with nano-SiO2 as well as the recycled polyester fiber has a positive effect on soil behaviors.展开更多
The aim of this study was to fabricate multi-layered recycled α-Fe<sub>2</sub>O<sub>3</sub>/OPEFB fiber/PCL composites for microwave absorbing applications in the 1 - 4 GHz frequency range. Th...The aim of this study was to fabricate multi-layered recycled α-Fe<sub>2</sub>O<sub>3</sub>/OPEFB fiber/PCL composites for microwave absorbing applications in the 1 - 4 GHz frequency range. The multi-layered composites were 6 mm thick and each consisted of a 2 mm thick layer of recycled α-Fe<sub>2</sub>O<sub>3</sub>/PCL composites at various loadings (5 wt% - 25 wt%) of 16.2 nm recycled α-Fe<sub>2</sub>O<sub>3</sub> nanofiller, placed between two layers of 2 mm thick OPEFB fiber/PCL composites blended at a fixed ratio of 7:3. The real (ε') and imaginary (ε") components of the relative complex permittivity were measured using the open-ended coaxial probe technique and the values obtained were applied as inputs for the Finite Element Method to calculate the reflection coefficient magnitudes from which the reflection loss (RL) properties were determined. Both ε' and ε" increased linearly with recycled α-Fe<sub>2</sub>O<sub>3</sub> nanofiller content and the values of ε' varied between 3.0 and 3.9 while the ε" values ranged between 0.26 and 0.64 within 1 - 4 GHz. The RL (dB) showed the most prominent values within the 1.38 - 1.46 GHz band with a minimum of -38 dB attained by the 25 wt% composite. Another batch of minimum values occurred in the 2.39 - 3.49 GHz range with the lowest of -25 dB at 2.8 GHz. The recycled α-Fe<sub>2</sub>O<sub>3</sub>/OPEFB fiber/PCL multi-layered composites are promising materials that can be engineered for solving noise problems in the 1 - 4 GHz range.展开更多
基金Funded by Joint Funds of the National Natural Science Foundation of China(No.U1904188)the Jiangxi Provincial Department of Education Science and Technology Project(Nos.GJJ171079,GJJ181023,and GJJ181022)。
文摘To solve the problem of only surface carbonation and realize high-efficiency carbonation of recycled coarse aggregate,the method of carbonated recycled coarse aggregate with nano materials pre-soaking was first put forward.The carbonation effect of modified recycled coarse aggregate with three different carbonation methods was evaluated,and water absorption,apparent density and crush index of modified recycled coarse aggregate were measured.Combined with XRD,SEM,and MIP microscopic analysis,the high-efficiency carbonation strengthening mechanism of modified recycled coarse aggregate was revealed.The experimental results show that,compared with the non-carbonated recycled coarse aggregate,the physical and microscopic properties of carbonated recycled coarse aggregate are improved.The method of carbonation with nano-SiO_(2) pre-soaking can realize the high-efficiency carbonation of recycled coarse aggregate,for modified recycled coarse aggregate with the method,water absorption is reduced by 23.03%,porosity is reduced by 44.06%,and the average pore diameter is 21.82 nm.The high-efficiency carbonation strengthening mechanism show that the pre-socked nano-SiO_(2) is bound to the hydration product Ca(OH)_(2) of the old mortar with nano-scale C-S-H,which can improve the CO_(2) absorption rate,accelerate the carbonation reaction,generate more stable CaCO_(3) and nano-scale silica gel,and bond to the dense three-dimensional network structure to realize the bidirectional enhancement of nano-materials and pressurized carbonation.It is concluded that the method of carbonation with nano-SiO_(2) pre-soaking is a novel high-efficiency carbonation modification of recycled coarse aggregate.
基金Project 51306198 supported by the National Natural Science Foundation of China
文摘Low critical temperature limits the application of CO_2 trans-critical power cycle.The binary mixture of R290/CO_2has higher critical temperature.Using mixture fluid may solve the problem that subcritical CO_2 is hardly condensed by conventional cooling water.In this article,theoretical analysis is executed to study the performance of the zeotropic mixture for trans-critical power cycle using low-grade liquid heat source with temperature of200℃.The results indicated that the problem that CO_2 can't be condensed in power cycle by conventional cooling water can be solved by mixing R290 to CO_2.Variation trend of outlet temperature of thermal oil in supercritical heater with heating pressure is determined by the composition of the mixture fluid.Gliding temperature causes the maximum outlet temperature of cooling water with the increase of mass fraction of R290.There are the maximum values for cycle thermal efficiency and net power output with the increase of supercritical heating pressure.
基金supported by the Chengdu Science and Technology Project of the Chengdu Bureau of Science and Technology(2021-YF05-00194-SN)the Foundation of Department of Science and Technology of Sichuan Province(2022NSFSC0203)。
文摘Dining lampblack as a source of atmospheric pollution,urban residents had to spend a lot of economic costs all year round to solve its impact.However,traditional treatment methods often carry the risk of secondary pollution.The use of phase change absorption solvent(PCAS)controlled by CO_(2)can effectively absorb the oily components in dining lampblack,and smoothly avoid the generation of secondary pollutants and squandering of resources.The reversibility of PCASs under CO_(2)control was explained by pH changes and macroscopic visualizations.The absorption effects of favorable absorbents and PCASs on dining lampblack were compared and analyzed.The fatty acid(FA)in the oil absorption mixture was desorbed by interacting with D230.The results of GC/MS analysis on the oil components separated by desorption showed that the desorption of PCASs was effective for these refractory oil components.FAs can be enriched and applied to the subsequent dining lampblack treatment link to realize the waste recycling.In addition,the absorption and desorption of oily components by PCASs were combined with the CO_(2)-controlled phase transformation of PCASs itself to achieve the absorption circulation of treating dining lampblack by using PCASs.
文摘This paper investigates the effect of recycled polyester fiber, produced from polyethylene （PET） bottles, in combination with nano-SiO2 as a new stabilizer to improve the mechanical properties of soils. We intend to study the effect of adding nano-SiO2 and recycled polyester fiber on soil engineering properties, especially the shear strength and unconfined compressive strength （UCS）, using clayey soil with low liquid limit. Three different combinations of fiber-soil ratios ranging between 0.1% and 0.5% as well as three different combinations of nano-soil ratios ranging between 0.5% and 1% are used. The shear strength and UCS of treated specimens are obtained from direct shear test and unconfined compression test, respectively. Results of this study show that the addition of recycled polyester fiber and nano-SiO2 increases the strength of soil specimens. Both the shear strength and UCS are improved by increasing the contents of recycled polyester fiber and nano-SiO2 in the soil mixture. The increase in the nano-SiO2 content leads to a reduction in failure strain, but the increase in the content of recycled polyester fiber leads to an increase in failure strain. The increase in the contents of recycled polyester fiber and nano-SiO2 leads to an increase in elastic modulus of soils. Based on the test results, the addition of recycled polyester fiber improves the mechanical properties of soils stabilized with nano-SiO2 as well as the recycled polyester fiber has a positive effect on soil behaviors.
文摘The aim of this study was to fabricate multi-layered recycled α-Fe<sub>2</sub>O<sub>3</sub>/OPEFB fiber/PCL composites for microwave absorbing applications in the 1 - 4 GHz frequency range. The multi-layered composites were 6 mm thick and each consisted of a 2 mm thick layer of recycled α-Fe<sub>2</sub>O<sub>3</sub>/PCL composites at various loadings (5 wt% - 25 wt%) of 16.2 nm recycled α-Fe<sub>2</sub>O<sub>3</sub> nanofiller, placed between two layers of 2 mm thick OPEFB fiber/PCL composites blended at a fixed ratio of 7:3. The real (ε') and imaginary (ε") components of the relative complex permittivity were measured using the open-ended coaxial probe technique and the values obtained were applied as inputs for the Finite Element Method to calculate the reflection coefficient magnitudes from which the reflection loss (RL) properties were determined. Both ε' and ε" increased linearly with recycled α-Fe<sub>2</sub>O<sub>3</sub> nanofiller content and the values of ε' varied between 3.0 and 3.9 while the ε" values ranged between 0.26 and 0.64 within 1 - 4 GHz. The RL (dB) showed the most prominent values within the 1.38 - 1.46 GHz band with a minimum of -38 dB attained by the 25 wt% composite. Another batch of minimum values occurred in the 2.39 - 3.49 GHz range with the lowest of -25 dB at 2.8 GHz. The recycled α-Fe<sub>2</sub>O<sub>3</sub>/OPEFB fiber/PCL multi-layered composites are promising materials that can be engineered for solving noise problems in the 1 - 4 GHz range.
